Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/03/15
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
931 AM MST TUE SEP 1 2015
.SYNOPSIS...
LOW END CHANCES FOR SHOWERS AND THUNDERSTORMS CONTINUE TODAY FROM
PHOENIX EAST...THEN INCREASE FURTHER FOR WEDNESDAY AND THURSDAY AS
LOW PRESSURE OFF THE CALIFORNIA MOVES INTO THE REGION. A RETURN OF
DRIER AIR INTO THE REGION WILL REDUCE CHANCES FOR SHOWERS AND
THUNDERSTORMS FROM FRIDAY ONWARD INTO THE UPCOMING WEEKEND.
&&
.DISCUSSION...
A RELATIVELY COOL AND MOIST MORNING ACROSS THE FORECAST AREA. AT 16Z
TEMPERATURES WERE QUICKLY WARMING ACROSS SE CA AND SW AZ BUT SLOWER
OVER THE PHOENIX AREA DUE TO LAST NIGHT/S STORMS. DEW POINTS WERE INT
HE MID 60S TO MID 70S. YUMA WAS REPORTING GUSTY SOUTHERLY WINDS WITH
DEW POINTS THERE AND AT EL CENTRO WELL OVER 70. KYUX VWP DEPICTING
SSE WINDS UP TO 5KFT OF 10-20 KT AND A 01.15Z RAOB THERE HAD A BL
MIXING RATIO OF ABOUT 17 G/KG. CLEARLY A SOLID SURGE UNDERWAY. DOES
NOT APPEAR THAT THERE IS ANY SHORT TERM GUIDANCE THAT IS STRONGLY
LATCHING ON TO THIS...THE HRRR IS INITIALIZING WELL BUT I/M CONCERNED
IT MIXES THE MOISTURE OUT MUCH TOO QUICKLY.
SO WHAT DOES THIS MEAN. DID MAKE SOME ADJUSTMENT ON
TEMPERATURES...GENERALLY DOWN A LITTLE BIT. LOOKING AT THE LATEST
HRRR-X RUNS AND NCAR ENS DATA...AND THE 01.12Z NAM...DON/T THINK OUR
STORM CHANCES ARE REALLY GONE FOR TODAY. WITH GOOD MOISTURE IN
PLACE...EVEN WITH SLIGHTLY REDUCED HEATING...SHOULD YIELD MLCAPE
VALUES IN EXCESS OF 500 J/KG THIS AFTERNOON AND EVENING. THERE ARE NO
CLEAR TRIGGERING/LIFTING MECHANISMS ATTM OUTSIDE OF DIURNAL
HEATING...SO TWO-OUT-OF-THREE INGREDIENTS IS ENOUGH TO WARRANT AT
LEAST A MENTION OF SHOWERS/STORMS IN THE FORECAST.
.PREVIOUS DISCUSSION...
WEDNESDAY AND THURSDAY...
THESE TWO DAYS /ESPECIALLY THURSDAY/ ARE EXPECTED TO BE MORE ACTIVE
WEATHERWISE ACROSS SOUTH-CENTRAL AZ...AS MID-LEVEL MOISTURE FROM THE
REMAINS OF TROPICAL CYCLONE 14E ARE SWEPT NORTHWARD INTO THE REGION
BY THE UPPER LOW TO OUR WEST. ALTHOUGH THE CENTER OF THIS TROPICAL
SYSTEM IS NOT EXPECTED TO GET EVEN REMOTELY CLOSE TO OUR REGION (THE
NHC HAS IT DISSIPATING OFF THE SOUTHERN BAJA COAST BY SAT
NIGHT)...THERE IS GOOD MODEL CONSENSUS ON THE TRACK OF THIS TROPICAL
SYSTEM /WITH A TIGHT GROUPING OF THE GFS ENSEMBLE MEMBERS/...WITH
THE GFS PULLING A SIGNIFICANT MOISTURE PLUME NORTHWARD INTO OUR
REGION...WITH PWATS EXCEEDING 1.80 INCH OVER SOUTH-CENTRAL ARIZONA BY
THURSDAY AFTERNOON. THE COMBINATION OF THIS MOISTURE ALONG WITH GOOD
VERTICAL WIND SHEAR /50KTS AT 300MB/...WITH LIKELY RESULT IN A
INCREASE IN CONVECTIVE ACTIVITY ON WEDNESDAY...AND WIDESPREAD
ACTIVITY ON THURSDAY. STORMS THAT DEVELOP WILL ONCE AGAIN BE CAPABLE
OF PRODUCING VERY STRONG WINDS AND LOCALLY HEAVY RAINS (ESPECIALLY ON
THURSDAY). THE COMBINATION OF INCREASED CLOUDINESS/RAINFALL AND
SOMEWHAT COOLER AIR ALOFT IS EXPECTED TO BRING HIGH TEMPS DOWN...WITH
MANY LOWER DESERT LOCATIONS ACROSS SOUTH-CENTRAL ARIZONA LIKELY
SEEING HIGHS ONLY IN THE 90S ON THURSDAY.
FRIDAY THROUGH TUESDAY...
ALTHOUGH THERE WILL BE REDUCTION IN AVAILABLE MOISTURE OVER THE
REGION AS SOUTHWESTERLY FLOW ALOFT SWEEPS THE MOISTURE FROM THE
REMAINS OF TROPICAL CYCLONE 14E OFF TO THE NORTH AND EAST...MORE
SOUTHERLY FLOW BELOW 700MB IS EXPECTED TO CONTINUE TO IMPORT AT LEAST
SOME MOISTURE INTO SOUTH-CENTRAL AZ...WITH PWATS REMAINING IN THE
1.00-1.50 INCH RANGE) DURING THE ENTIRE PERIOD. THIS LEFT-OVER
MOISTURE...COMBINED WITH FAIR-TO-GOOD VERTICAL WIND SHEAR IS EXPECTED
TO ALLOW AT LEAST SOME SHOWER/THUNDERSTORM ACTIVITY TO DEVELOP EACH
DAY. ON THE OTHER HAND...MUCH DRIER AIR OVER SE CA/SW AZ IS EXPECTED
TO KEEP THOSE REGIONS PRETTY MUCH THUNDERSTORM-FREE DURING THIS
PERIOD.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
GIVEN THE WIDESPREAD CONVECTION MONDAY EVENING...THE ATMOSPHERE IS
LIKELY TOO CONTAMINATED TO SUPPORT ADDITIONAL STORMS TODAY. COULD SEE
SOME DISTANT STORMS WELL EAST AND SOUTH OF PHOENIX BUT AT THIS POINT
NEARLY ALL NUMERICAL GUIDANCE SUGGESTS THE PHOENIX AREA TERMINALS
WILL BE IN THE CLEAR THIS AFTERNOON. GOING WITH THE IDEA OF SOME
AFTERNOON CU ALONG WITH TYPICAL DIURNAL WINDS,
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
FEW/SCT HIGH CLOUDS SHOULD BE THE RULE ACROSS SOUTHWEST AZ/SOUTHEAST
CA THIS AFTERNOON. NO WEATHER-RELATED AVIATION IMPACTS EXPECTED.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
MOISTURE WILL INCREASE ACROSS THE AREA BY THE MIDDLE OF THE WEEK
RESULTING IN ELEVATED STORM CHANCES FROM PHOENIX EASTWARD ON
THURSDAY. MOISTURE VALUES WILL WANE A BIT INTO THE WEEKEND ALTHOUGH
DAILY STORM CHANCES WILL REMAIN PRESENT THROUGH EARLY NEXT WEEK. MINIMUM
RH VALUES WILL FALL BELOW 15 PERCENT THURSDAY ACROSS SOUTHEAST
CALIFORNIA WITH VALUES ABOVE 15 PERCENT EXPECTED EAST OF THE LOWER
COLORADO RIVER. FOR FRIDAY INTO THE WEEKEND...LATEST GUIDANCE MORE
INSISTENT UPON A RETURN TO DEEPER MOISTURE...HIGHER HUMIDITY AND
BETTER RAIN CHANCES...PARTICULARLY ACROSS SOUTH CENTRAL ARIZONA.
&&
.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT CONDITIONS ACCORDING TO STANDARD
OPERATING PROCEDURES.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
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DISCUSSION...INIGUEZ/MP
AVIATION...MP
FIRE WEATHER...MP
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
1025 PM MST MON AUG 31 2015
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS WILL TREND DOWN FROM WEST TO EAST THE REST
OF THE NIGHT. LINGERING STORM CHANCES WILL CONTINUE EAST OF THE LOWER
COLORADO RIVER VALLEY TUESDAY THROUGH THURSDAY. MOISTURE IS EXPECTED
TO INCREASE LATE IN THE WEEK WITH WITH STORM CHANCES OVER A BROADER
AREA FRIDAY THROUGH THE WEEKEND. A GRADUAL COOLING TREND IS ALSO
ANTICIPATED THIS WEEK THROUGH THURSDAY.
&&
.DISCUSSION...
ISOLATED WEAK STORMS LATE THIS AFTERNOON NEAR AND SOUTH OF THE
ESTRELLAS QUICKLY BLEW UP INTO MUCH MORE OVER METRO PHOENIX. THE
INITIAL STRONG STORM PRODUCED A DOWNBURST OVER THE ESTRELLAS. THEN AN
EVEN STRONGER SUBSEQUENT STORM FROM THAT OUTFLOW BLEW UP NEAR THE
STATE FAIRGROUNDS. THOSE COMBINED OUTFLOWS IN ADDITION TO OUTFLOWS FROM
PINAL COUNTY...INITIALLY SOUTH OF FLORENCE...AS WELL AS GILA COUNTY
HAVE HELPED TO CREATE WIDESPREAD SHOWERS AND THUNDERSTORMS ACROSS
NORTHEAST MARICOPA COUNTY AND PINAL COUNTY. WITH A WESTERLY COMPONENT
TO THE STEERING FLOW...STORMS ARE GENERALLY MOVING TO THE EAST BUT
BOUNDARY INTERACTIONS ARE AIDING ISOLATED REDEVELOPMENT IN AREAS
THAT ALREADY HAD STORM ACTIVITY. DESPITE AN ENVIRONMENT THAT HAD
MODEST PRECIPITABLE WATER AND SURFACE DEW POINTS...STORMS HAVE BEEN
ABLE TO PRODUCE FLASH FLOODING. AS OF THIS WRITING...THE ACTIVITY HAS
ENDED FOR MUCH OF THE METRO AREA WITH NORTHERN AND EASTERN PERIPHERY
STILL LINGERING BUT MORE ACTION OVER NORTHERN PINAL COUNTY. THIS WILL
LARGELY SETTLE DOWN BY MIDNIGHT. IT REMAINS TO BE SEEN HOW THE MCS
OVER SONORA INFLUENCES THINGS LATE TONIGHT. HRRR HAS BEEN INDICATING
LATE NIGHT DEVELOPMENT ASSOCIATED WITH THAT SYSTEM BUT IT HAS NOT
HANDLED TONIGHT/S ACTIVITY VERY WELL. STEERING FLOW SHOULD KEEP
DEBRIS CLOUDS FROM BEING TOO THICK BUT SURFACE DEW POINTS LOOK LIKE
THEY SHOULD INCREASE TUESDAY...ESPECIALLY OVER SOUTHWEST ARIZONA.
TONIGHT/S ACTIVITY SHOULD LEAVE BEHIND FAIRLY STABLE CONDITIONS FOR
TUESDAY. BUT WITH MOISTURE AVAILABLE AND PERHAPS ACTIVITY OVER
SOUTHWEST ARIZONA...SOUTH-CENTRAL ARIZONA MAY HAVE ANOTHER
OPPORTUNITY FOR STORMS TUESDAY. LOTS MORE FOR THE NIGHT SHIFT TO
EVALUATE.
&&
.PREVIOUS DISCUSSION ISSUED 233 PM...
LATEST STREAMLINE ANALYSIS SHOWS THAT THE RIDGE HAS DRIFTED SLIGHTLY
TO THE EAST...BUT OVERALL VERY LITTLE HAS CHANGED SYNOPTICALLY OVER
THE PAST FEW DAYS. INTERESTING TO NOTE THAT THE NCAR ENSEMBLE PICKED
UP ON THE MORNING ACTIVITY ACROSS GILA COUNTY AND CONSEQUENTLY MORE
WEIGHT WAS ASSIGNED TO THIS GUIDANCE THROUGH THE EVENING.
OTHER CONVECTIVE ALLOWING GUIDANCE CONTINUES TO SUGGEST THAT
ISOLATED/SCATTERED THUNDERSTORMS WILL AGAIN DEVELOP ACROSS THE
PHOENIX AREA AND POINTS EASTWARD THIS EVENING...AIDED BY SUFFICIENT
LOW-LEVEL MOISTURE...BOUNDARY PROPAGATION FROM THE SOUTH AND
RELATIVELY COOL TEMPERATURES ALOFT ASSOCIATED WITH A TROUGH TO THE
WEST. LATEST ACARS SOUNDINGS SHOW THAT STEERING FLOW HAS VEERED
SLIGHTLY TO THE SOUTHWEST...WHICH AT LEAST CONCEPTUALLY SHOULD FOCUS
ACTIVITY SOMEWHAT FURTHER EAST THAN IN PREVIOUS NIGHTS. A WARM LAYER
NEAR 700 MB IS ALSO EVIDENT...WHICH IS LIKELY RESULTING IN
CONSIDERABLE CONVECTIVE INHIBITION AND MOSTLY CLEAR SKIES ACROSS THE
PHOENIX AREA.
U OF A WRFS HAVE PERFORMED WELL THE PAST FEW EVENINGS AND AGAIN
INDICATE THAT SCATTERED ACTIVITY IS POSSIBLE ACROSS THE PHOENIX AREA.
FORECAST POPS WERE INCREASED TO 20-30 PERCENT ACROSS PORTIONS OF
SOUTH-CENTRAL AZ FOR TONIGHT. MOST AREAS WILL NOT SEE MEASURABLE
RAINFALL...THOUGH LIGHTNING...GUSTY WINDS AND AREAS OF BLOWING DUST
ARE MORE PROBABLE.
FORECAST CONFIDENCE TUESDAY THROUGH THURSDAY IS LOW. DETERMINISTIC
GUIDANCE TAKEN AT FACE VALUE WOULD SUGGEST A DOWNWARD TREND IN STORMS
THROUGH MID WEEK...HOWEVER PROBABILISTIC TOOLS SUGGEST THE BL WILL
REMAIN MOIST WITH MODEST INSTABILITY ACROSS THE REGION. OF COURSE THE
MISSING INGREDIENT IS A TRIGGER TO KICK OFF STORMS IN THE FIRST PLACE
AND NONE OF THE DETERMINISTIC GUIDANCE INDICATE MUCH IN THE WAY OF
INVERTED TROUGHS OR LARGER SCALE FEATURES. WILL HANG ONTO SOMEWHAT
ELEVATED POPS /HIGHER THAN CLIMO/ THROUGH MID WEEK ON THE PREMISE
THAT STORMS WILL BE TRIGGERED BY COLLIDING OUTFLOWS.
FORECAST CONFIDENCE ISN`T MUCH HIGHER LATER IN THE FORECAST PERIOD.
IT WOULD APPEAR THAT MOISTURE WILL BE DRAWN INTO THE REGION FROM THE
TROPICS LATE IN THE WEEK /FRIDAY-SATURDAY/ ALTHOUGH EXACTLY WHERE
THIS AXIS OF DEEPEST MOISTURE RESIDES IS STILL UP FOR DEBATE.
00Z DETERMINISTIC GFS AND ECMWF SUGGEST ANOMALOUSLY HIGH PWATS AND
MIXING RATIOS WILL OVERSPREAD MUCH OF THE DESERT SOUTHWEST WHEREAS
GEFS AND NAEFS KEEP THIS MOISTURE SOUTH OF THE INTERNATIONAL BORDER
AND SHIFT IT TOWARD THE AZ/NM BORDER. GIVEN THE MAGNITUDE OF THE
700-300MB FLOW DURING THIS TIME PERIOD /AROUND 30-40KTS/...I`M
SKEPTICAL THE MOISTURE WILL REMAIN CONFINED TO THE BORDER AND POINTS
SOUTH. DEWPOINTS HAVE BEEN BUMPED UP LATE IN THE WEEK AND POPS HAVE
ALSO BEEN ELEVATED A BIT OVER INHERITED VALUES /MORE IN LINE WITH
CLIMO/. COULD END UP SEEING ELEVATED RAIN CHANCES LATE IN THE WEEK
INTO THE WEEKEND...BUT COULD JUST AS EASILY SEE INCREASE CLOUD COVER
AND DRY CONDITIONS DEPENDING ON WHERE THE MOISTURE AXIS POSITIONS
ITSELF. THUS CONFIDENCE IN PRECIP CHANCES IS LOW. FAIRLY HIGH
CONFIDENCE IN LOWER TEMPERATURES LATE IN THE WEEK WITH SOME OF THE
RAW UN-CORRECTED GUIDANCE POINTING TO HIGHS IN THE UPPER 90S. LOWERED
TEMPERATURES A FEW DEGREES FROM FRIDAY ONWARD ACCORDINGLY.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
MAIN BAND OF STORMS AS OF 05Z IS SHIFTING EASTWARD OUT OF THE METRO
PHOENIX AREA BUT ISOLATED REDEVELOPMENT CONTINUES. ANTICIPATE MOST OF
THE ACTIVITY OVER THE LOWER DESERTS WILL DISSIPATE BY 07Z-08Z.
EAST AND SOUTHEAST SURFACE WINDS SHOULD PREDOMINATE REST OF NIGHT AND
WELL INTO THE DAY TUESDAY.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
ANTICIPATE CLEAR SKIES EXCEPT FOR SOME VERY MINOR CIRRUS. TYPICAL
WARM SEASON WIND PATTERNS WILL PREVAIL...THOUGH THE FAVORED DAYTIME
SOUTH AND SOUTHEAST WINDS MAY BE A BIT STRONGER THAN USUAL TUESDAY.
ALSO ANTICIPATE SOME ISOLATED STORMS OVER SOUTHWEST ARIZONA TUESDAY
AFTERNOON.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
A LOW PRESSURE SYSTEM ACROSS THE PACIFIC NORTHWEST WILL DISPLACE THE
MONSOON HIGH SLIGHTLY TO THE SOUTH AND EAST THROUGH THE WEEK. THE
TREND WILL BE TOWARDS COOLER CONDITIONS ACROSS THE DESERT SOUTHWEST
WITH HIGH TEMPERATURES NEAR OR SLIGHTLY BELOW SEASONAL NORMALS EACH
DAY. HOWEVER SUFFICIENT MOISTURE WILL LINGER ACROSS EASTERN ARIZONA
TO KEEP AT LEAST A SLIGHT CHANCE FOR THUNDERSTORMS FROM PHOENIX EAST
WEDNESDAY INTO THURSDAY. MINIMUM RH VALUES WILL FALL BELOW 15
PERCENT WEDNESDAY AND THURSDAY ACROSS SOUTHEAST CALIFORNIA WITH
VALUES ABOVE 15 PERCENT EXPECTED EAST OF THE LOWER COLORADO RIVER.
FOR FRIDAY INTO THE WEEKEND...LATEST GUIDANCE MORE INSISTENT UPON A
RETURN TO DEEPER MOISTURE...HIGHER HUMIDITY AND BETTER RAIN
CHANCES...PARTICULARLY ACROSS SOUTH CENTRAL ARIZONA.
&&
.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT CONDITIONS ACCORDING TO STANDARD
OPERATING PROCEDURES.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
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DISCUSSION...AJ
PREVIOUS DISCUSSION...HIRSCH/LEINS
AVIATION...AJ
FIRE WEATHER...CB/HIRSCH
AREA FORECAST DISCUSSION
NWS TUCSON AZ
940 PM MST MON AUG 31 2015
.SYNOPSIS...SCATTERED THUNDERSTORMS WILL OCCUR AGAIN TUESDAY
AFTERNOON AND EVENING. A WEAK DRYING TREND AND WEAK FLOW WILL TEND
TO LIMIT MOST THUNDERSTORM ACTIVITY TO AREAS EAST OF TUCSON THE
SECOND HALF OF THE WEEK. INCREASING MOISTURE FROM THE SOUTH WILL
BRING A BETTER CHANCE OF SHOWERS AND THUNDERSTORMS THIS WEEKEND.
&&
.DISCUSSION...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WERE
OCCURRING GENERALLY NORTHEAST OF THE INTERSTATE-10 CORRIDOR AT THIS
TIME. BASED ON RADAR TRENDS AND SEVERAL HRRR SOLUTIONS...SCATTERED
SHOWERS AND THUNDERSTORMS WILL CONTINUE DURING THE NEXT SEVERAL
HOURS MAINLY FROM TUCSON METRO AREA NORTH-TO-NORTHEAST ACROSS
SOUTHEAST PINAL COUNTY...GRAHAM COUNTY AND NRN GREENLEE COUNTY. THE
MAIN CONCERN WILL BE THE POTENTIAL FOR LOCALLY HEAVY RAINFALL AND
BRIEF STRONG AND GUSTY WINDS. HAVE MAINTAINED ISOLATED SHOWERS/TSTMS
SOUTH-TO-SOUTHEAST OF TUCSON THE REST OF TONIGHT. HOWEVER...THE BULK
OF THE HEAVIER RAINFALL AMOUNTS WILL ALMOST CERTAINLY OCCUR WITH THE
SHOWERS/TSTMS ACROSS NERN SECTIONS. SEVERAL HRRR SOLUTIONS SUGGEST
THE BULK OF ANY SHOWERS/TSTMS WILL END AROUND SUNRISE TUE. ADEQUATE
MOISTURE WILL JUSTIFY A SLIGHT CHANCE OF SHOWERS/TSTMS TO OCCUR
MAINLY FROM TUCSON EWD/SWD LATE TUE MORNING.
PLEASE REFER TO THE ADDITIONAL SECTIONS FOR FURTHER DETAIL.
&&
.AVIATION...VALID THRU 02/06Z.
SCATTERED TO PERHAPS NUMEROUS -TSRA/-SHRA MAINLY FROM KTUS VICINITY
NEWD TO THE WHITE MOUNTAINS NE OF KSAD THE REST OF TONIGHT. THESE
-TSRA/-SHRA SHOULD REMAIN NORTH OF THE KOLS/KDUG TERMINALS. THE BULK
OF THIS ACTIVITY IS EXPECTED TO END AROUND DAYBREAK TUESDAY. EXPECT
SCATTERED -TSRA/-SHRA MAINLY FROM KTUS VICINITY EWD TO THE NEW
MEXICO BORDER TUESDAY AFTERNOON AND EVENING. BRIEF MVFR CONDITIONS
AND GUSTY WINDS TO 45 KTS MAY OCCUR WITH WITH THE STRONGER
THUNDERSTORMS. OTHERWISE...CLOUD DECKS WILL GENERALLY RANGE FROM 8-
12K FT AGL AND SURFACE WIND WILL GE MOSTLY LESS THAN 10 KTS.
AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...SCATTERED AFTERNOON AND EVENING THUNDERSTORMS WILL
CONTINUE THROUGH THURSDAY WITH A BIT OF AN EASTWARD SHIFT IN THE
ACTIVITY EACH DAY. WITH SOUTHWEST FLOW ALOFT...STORMS WILL
GENERALLY MOVE TOWARD THE NORTHEAST OUTSIDE THE INFLUENCE OF
OUTFLOWS. FOR THE MOST PART STORMS WILL BE DECENT RAINERS WITH WIND
GUSTS IN THE 25-40 MPH RANGE...WHILE A COUPLE EACH DAY WILL BE
STRONGER. THROUGH MUCH OF THE COMING WEEK WINDS WILL BE LIGHT WITH A
WEST TO SOUTHWEST 10-15 MPH BREEZE EACH AFTERNOON. FROM FRIDAY
ONWARD THERE IS THE POTENTIAL FOR THE SOUTHWEST FLOW ALOFT TO
CAPTURE REMNANT TROPICAL SYSTEMS AND DIRECT THAT MOISTURE UP ACROSS
OUR AREA FOR PERIODS OF ENHANCEMENT TO THE PRECIPITATION POTENTIAL.
&&
.PREV DISCUSSION /230 PM MST/...THEREAFTER...THE GFS AND ECMWF
DIFFER ON HOW MUCH DRYING TAKES PLACES AS A LOW PRESSURE TROUGH
DEEPENS ALONG THE WEST COAST...AND THE SOUTHWESTERLY FLOW ALOFT
INCREASES ACROSS THE AREA. FOR NOW...WILL CONTINUE TO ADVERTISE A
DECREASE AND EASTERLY SHIFT IN RAIN CHANCES FOR TOMORROW INTO AT
LEAST FRIDAY. FORECAST BECOMES MORE UNCERTAIN THIS WEEKEND AS THE
GFS AND ECMWF SHOWED WIDELY DIFFERENT SOLUTIONS IN THE STRENGTH AND
TRACK OF A SYSTEM MOVING INTO THE PACIFIC NORTHWEST. FOR NOW...WILL
LEAN MORE TOWARD THE GFS SOLUTION WHICH SUGGESTED THAT THERE MIGHT
BE SOME TROPICAL INFLUENCE FROM THE EASTERN PACIFIC AS A POSSIBLE
SYSTEM HELPS PUSH DEEPER MOISTURE BACK INTO THE AREA BY THE WEEKEND.
OTHERWISE...HIGH TEMPERATURES WILL BE NEAR SEASONABLE READINGS THIS
WEEK.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS PUEBLO CO
711 PM MDT WED SEP 2 2015
.UPDATE...
ISSUED AT 707 PM MDT WED SEP 2 2015
UPDATED MAINLY POPS IN THE GRIDS/ZONES TO REFLECT LATEST
RADAR TRENDS AND HI RES GUIDANCE. LOTS OF UPSTREAM CONVECTION
STILL MOVING NWD THROUGH NRN NM...AND SOME OF THIS SHOULD MOVE
INTO SC AND SE CO THIS EVENING.BEST COVERAGE WILL BE OVER THE ERN
MTS AND SURROUNDING AREAS OVER THE NEXT FEW HOURS. WITHOUT
ANY STRONG FORCING...SHOULD SEE CONVECTION DIMINISH LATER THIS
EVE BUT CANNOT RULE OUT SOME ISOLD ACTIVITY OVER THE LOWER
ELEVATIONS. LATE TONIGHT...WILL START TO SEE THE INFLUENCE OF
A SURGE OF MONSOONAL MOISTURE INTO SW CO...SO HAVE BOOSTED POPS
SLIGHTLY EARLY THU FOR THE CONTDVD. ROSE
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 307 PM MDT WED SEP 2 2015
CONVECTION SLOWLY BEGINNING TO INCREASE ACROSS THE AREA THIS
AFTERNOON...WITH STORMS MOST NUMEROUS OVER THE SOUTHWEST MOUNTAINS
AND ALONG THE NM BORDER WHERE MOISTURE AND INSTABILITY IS GREATEST.
FOR THE REST OF THE AFTERNOON INTO THE EVENING...EXPECT CONVECTION
TO EXPAND SOMEWHAT OVER THE MOUNTAINS AND INTERIOR VALLEYS AS WEAK
UPPER WAVE AND INCREASING MID LEVEL MOISTURE MOVE INTO CO FROM NWRN
NM. HRRR SUGGESTS SOME WEAKENING STORMS TO PERHAPS REACH THE I-25
CORRIDOR AROUND KPUB AND KCOS THIS EVENING...THOUGH RATHER LOW CAPE
(200-400 J/KG) ACROSS THESE AREAS SUGGESTS STORMS WILL STAY ISOLATED
AND WEAK. A FEW STORMS WILL ALSO BE POSSIBLE ALONG THE NORTH SLOPE
OF THE RATON MESA EASTWARD ACROSS LAS ANIMAS COUNTY...WHILE
REMAINDER OF THE PLAINS SHOULD BE TOO STABLE TO SUPPORT ANY EVENING
CONVECTION. OVERNIGHT...STORMS WILL END OVER THE EASTERN HALF OF THE
AREA...WHILE A FEW -SHRA/WEAK -TSRA HANG ON ALONG THE CONTINENTAL
DIVIDE WHERE MOISTURE CONTINUES TO ADVECT NORTHWARD FROM AZ/NM.
ON THU...EXPECT FAIRLY WIDESPREAD CONVECTION OVER THE MOUNTAINS FROM
THE SANGRES WESTWARD AS DEEP MOIST AIR MASS WILL BE OVER THE
AREA...WHILE EASTERN MOUNTAIN SLOPES/I25 CORRIDOR/SOUTHEAST PLAINS
SEE MUCH LESS ACTIVITY UNDER RATHER UNFAVORABLE W-SW WINDS AT THE
SURFACE AND ALOFT. GIVEN RATHER HEALTHY PRECIPITABLE WATER
VALUES...STORMS OVER THE HIGHER TERRAIN WILL HAVE THE POTENTIAL FOR
FAIRLY HEAVY RAINFALL RATES...THOUGH RELATIVELY STRONG STEERING
CURRENTS SHOULD KEEP ACTIVITY MOVING AND REDUCE THE FLOOD HAZARD
SOMEWHAT. MAX TEMPS OVER THE MOUNTAINS AND VALLEYS SHOULD COOL A FEW
DEGF FROM WED MAXES...WHILE I-25 CORRIDOR AND EASTERN PLAINS SEE
LITTLE CHANGE WITH RATHER HOT TEMPS PERSISTING.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 307 PM MDT WED SEP 2 2015
THURSDAY NIGHT THROUGH SATURDAY...FAIRLY GOOD MODEL AGREEMENT
BETWEEN THE GFS AND EC INTO THE WEEKEND...AS COLORADO REMAINS IN THE
MIDDLE OF A RIDGE OF HIGH PRESSURE TO THE EAST.,..AND A
STRENGTHENING LOW PRESSURE SYSTEM OVER THE PAC NW. THIS WILL PRODUCE
BRISK SW FLOW ALOFT ACROSS THE 4 CORNERS AND COLORADO...DRAWING A
HEALTHY AMOUNT OF MONSOON MOISTURE INTO THE FORECAST AREA. THIS WILL
ALSO ENCOURAGE DIURNAL CONVECTION EACH AFTN AND EVENING...WITH
ISOLATED TO SCATTERED POPS OVER THE MTS AND ISOLATED ELSEWHERE. LOOK
FOR MILD NIGHTS...AND MAX TEMPS EACH AFTN IN THE 70S TO NEAR 80 FOR
THE HIGH VALLEYS...AND AROUND 90 F FOR THE E PLAINS.
SUNDAY AND MONDAY...MODELS START TO DISAGREE BEGINNING ON SUN. THE
UPPER LOW OVER THE PAC NW WILL ROTATE ACROSS THE NORTHERN ROCKIES ON
SAT...MT ON SUN AND BACK NORTH INTO CANADA FOR MON. THE FLOW ALOFT
WILL TRANSITION TO A MORE WESTERLY DIRECTION...TEMPORARILY CUTTING
OFF THE MONSOON TAP FROM THE SW. MODELS SOMEWHAT AGREE ON THIS...BUT
THE GFS STARTS TO SNEAK MOISTURE BACK UP INTO THE STATE MON AFTN AND
EVE. FEEL THIS IS REASONABLE SINCE THERE WILL STILL BE PLENTY OF
DAYTIME HEATING...SO KEPT ISOLATED POPS OVER THE MTS...MAINLY ALONG
THE CONTDVD...MON AFTN AND EVE.
TUESDAY AND WEDNESDAY...THE EC LEANS TOWARDS KEEPING THE ENTIRE AREA
DRY THROUGH WED...WHILE THE GFS HAS MORE OF A SW FLOW ALOFT WHICH
ATTEMPTS TO DRAW SOME OF THE MONSOON MOISTURE BACK INTO THE STATE.
DECIDED TO SIDE WITH THE GFS...BUT KEPT POPS LIGHT THROUGH WED WHILE
COOLING MAX TEMPS BOTH DAYS BY ABOUT 5 DEGREES. MOORE
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 307 PM MDT WED SEP 2 2015
TSRA WILL REMAIN CONFINED MAINLY TO THE MOUNTAINS/INTERIOR VALLEYS
INTO THIS EVENING...AND WILL CARRY A VCTS MENTION ONLY AT KALS FOR
LATE AFTERNOON INTO THE EVENING. COULD SEE SOME VERY WEAK CONVECTION
DRIFT OFF THE MOUNTAINS TOWARD KCOS AND KPUB 23Z-03Z...BUT DOUBTFUL
THEY WILL LAST LONG ENOUGH TO REACH EITHER TERMINAL AND WON`T
INCLUDE A MENTION IN THE TAFS AT THIS POINT. OVERNIGHT...SOME WEAK
CONVECTION WILL LINGER ALONG THE CONTINENTAL DIVIDE INTO THU
MORNING...WITH POSSIBLY SOME MVFR CIGS/VIS OVER THE HIGHER PEAKS AND
PASSES. ON THU...CONVECTION WILL BECOME FAIRLY WIDESPREAD BY
AFTERNOON OVER THE MOUNTAINS...ESPECIALLY ALONG THE CONTINENTAL
DIVIDE WHERE AREAS OF IFR CONDITIONS WILL BE LIKELY THROUGH THE DAY.
FOR THE TAF SITES...BEST CHANCE OF TSRA THU WILL BE AT KALS...LESSER
CHANCES AT KPUB AND KCOS.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...ROSE
SHORT TERM...PETERSEN
LONG TERM...MOORE
AVIATION...PETERSEN
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1156 AM MDT TUE SEP 1 2015
.UPDATE...
ISSUED AT 1150 AM MDT TUE SEP 1 2015
DRIER AIRMASS TODAY BUT STILL SOME MOISTURE AROUND. BAND OF DEEPER
MOISTURE AND WEAK LIFT HAS SHIFTED TO THE SOUTHEAST FRINGE OF OUR
AREA...THERE SHOULD BE SOME WEAK FORCING IN THIS AREA WHICH WILL
HELP CENTRAL MOUNTAIN/PALMER DIVIDE CONVECTION THIS AFTERNOON.
ACROSS NORTHEASTERN COLORADO IT SHOULD BE PRETTY WELL CAPPED.
THERE IS ALSO A LITTLE JET STREAK PRODUCING CONVECTION IN CENTRAL
UTAH AT THIS HOUR...THIS WILL PROBABLY MOVE ACROSS THE NORTHERN
MOUNTAINS IN THE LATE AFTERNOON/EARLY EVENING. MADE SOME MINOR
ADJUSTMENTS TO POPS AND CLOUDS TO REFLECT EXPECTED TIMING OF THESE
FEATURES.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 438 AM MDT TUE SEP 1 2015
WEAK WEST-SOUTHWESTERLY FLOW ALOFT IS GOING TO CONTINUE ACROSS
COLORADO TODAY WITH ADDITIONAL SUB-TROPICAL MOISTURE. ANOTHER
ROUND OF SHOWERS IS GOING TO BE POSSIBLE...ESPECIALLY OVER THE
MOUNTAINS. WINDS ALOFT WILL BE WEAK...WHICH COULD RESULT IN SLOW
STORM MOTIONS AND LOCALLY HEAVY RAINFALL. THE RAP AND NAM MODELS
KEEP MOST OF THE QPF OVER THE MOUNTAINS...ALTHOUGH THE NAM
PRODUCES SOME RAIN OUT ACROSS THE PALMER DIVIDE.
FORECAST WILL HAVE THE HIGHEST CHANCES OF PRECIPITATION OVER THE
MOUNTAINS...AND ISOLATED COVERAGE ACROSS THE PLAINS. TEMPERATURES
WILL BE SLIGHTLY WARMER THAN NORMAL. TURNING THE CALENDAR TO
SEPTEMBER HAS NOT QUITE BROUGHT AN END TO SUMMER YET.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 438 AM MDT TUE SEP 1 2015
THE FLOW ALOFT WILL CONTINUE SWLY BOTH WED AND THU AS AN UPPER LEVEL
TROUGH RESIDES OVER THE PACIFIC NW. BOTH THE ECMWF AND GFS SHOW
SOME SUBTROPICAL MOISTURE EMBEDDED IN THE FLOW WHICH WILL BE OVER
THE AREA BOTH DAYS. PRECIPITABLE WATER VALUES WILL BE IN THE 0.5-0.6
INCH RANGE OVER THE MTNS WITH VALUES FM 0.8-1.0 INCHES OVER THE
PLAINS. OVERALL WILL KEEP IN A SLIGHT CHC OF STORMS BOTH DAYS ACROSS
THE AREA. AS FOR HIGHS READINGS WILL REMAIN ABV NORMAL BOTH DAYS
WITH LOW TO MID 90S OVER NERN CO.
BY FRI LITTLE CHANGE IS EXPECTED AS AN UPPER LEVEL TROUGH REMAINS
OVER THE PACIFIC NW WITH SWLY FLOW ALOFT REMAINING OVER THE AREA
WITH SOME SUBTROPICAL MOISTURE STILL EMBEDDED IN THE FLOW.
PRECIPITABLE WATER VALUES INCREASE SLIGHTLY WITH 0.6-0.7 INCHES IN
THE MTNS WITH VALUES AOA AN INCH ACROSS THE PLAINS. THUS THERE MAY
BE SOME INCREASE IN COVERAGE FOR FRI AFTN INTO FRI EVENING. AS FOR
TEMPS READINGS WILL REMAIN ABV NORMAL OVER NERN CO WITH HIGHS IN THE
UPPER 80S TO LOWER 90S.
ON SAT THE UPPER LEVEL TROUGH WILL BEGIN TO SHIFT SLOWLY EASTWARD
WITH SWLY FLOW STILL OVER THE AREA. BOTH THE ECMWF AND GFS SHOW
SOME MID LVL DRYING BY AFTN ESPECIALLY IN THE MTNS AS PRECIPITABLE
WATER VALUES DROP BELOW 0.50 INCHES SO TSTM ACTIVITY SHOULD BE
LESS OVER THE HIGHER TERRAIN. OVER NERN CO PRECIPITABLE WATER
VALUES ARE STILL FCST TO BE AOA AN INCH. MEANWHILE THERE APPEARS
TO BE A WK BNDRY THAT WILL BE OVER NERN CO IN THE AFTN WHICH MAY
ACT AS A FOCUS FOR TSTM DEVELOPMENT. AS FOR HIGHS 850-700 MB TEMPS
DROP A FEW DEGREES SO WILL KEEP READINGS IN THE 80S OVER NERN CO.
BY SUN THE THE UPPER LEVEL TROUGH WILL MOVE INTO THE NRN ROCKIES
WITH WSW FLOW ALOFT OVER THE AREA. BOTH THE ECMWF AND GFS HAVE A
RATHER DRY AIRMASS OVER THE AREA WITH A SUBSTANTIAL DECREASE IN
PRECIPITABLE WATER VALUES. IF THIS IS THE CASE THEN ANY TSTM
ACTIVITY WILL BE PRETTY ISOLD AND CONFINED TO THE PLAINS. AS FOR
HIGHS READINGS WILL REMAIN ABV NORMAL WITH MID 80S TO LOWER 90S
ACROSS NERN CO.
ON MON THE FLOW ALOFT WILL REMAIN WSW AS A COOL FRONT IS SUPPOSED TO
MOVE ACROSS NERN CO...HOWEVER THE STRENGTH OF THIS FNT IS WEAKER
THAN WHAT THE MODELS SHOWED YESTERDAY. OVERALL THERE WILL BE
LIMITED MOISTURE SO WILL ONLY MENTION LOW POPS. HIGHS WILL DROP
BACK INTO THE UPPER 70S TO LOWER 80S OVER THE PLAINS.
&&
.AVIATION...(FOR THE TAFS THROUGH 18Z WEDNESDAY MORNING)
ISSUED AT 1150 AM MDT TUE SEP 1 2015
VFR THROUGH TONIGHT. ISOLATED THUNDERSTORMS EXPECTED IN THE LATE
AFTERNOON/EARLY EVENING...MOST LIKELY SOUTH OF DENVER. STILL A
GOOD CHANCE OF A SHORT PERIOD OF GUSTY WINDS TO 30 KNOTS...BUT
ONLY LOW PROBABILITIES OF ANY OTHER IMPACTS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GIMMESTAD
SHORT TERM...DANKERS
LONG TERM...RPK
AVIATION...GIMMESTAD
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
438 AM MDT TUE SEP 1 2015
.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 438 AM MDT TUE SEP 1 2015
WEAK WEST-SOUTHWESTERLY FLOW ALOFT IS GOING TO CONTINUE ACROSS
COLORADO TODAY WITH ADDITIONAL SUB-TROPICAL MOISTURE. ANOTHER
ROUND OF SHOWERS IS GOING TO BE POSSIBLE...ESPECIALLY OVER THE
MOUNTAINS. WINDS ALOFT WILL BE WEAK...WHICH COULD RESULT IN SLOW
STORM MOTIONS AND LOCALLY HEAVY RAINFALL. THE RAP AND NAM MODELS
KEEP MOST OF THE QPF OVER THE MOUNTAINS...ALTHOUGH THE NAM
PRODUCES SOME RAIN OUT ACROSS THE PALMER DIVIDE.
FORECAST WILL HAVE THE HIGHEST CHANCES OF PRECIPITATION OVER THE
MOUNTAINS...AND ISOLATED COVERAGE ACROSS THE PLAINS. TEMPERATURES
WILL BE SLIGHTLY WARMER THAN NORMAL. TURNING THE CALENDAR TO
SEPTEMBER HAS NOT QUITE BROUGHT AN END TO SUMMER YET.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 438 AM MDT TUE SEP 1 2015
THE FLOW ALOFT WILL CONTINUE SWLY BOTH WED AND THU AS AN UPPER LEVEL
TROUGH RESIDES OVER THE PACIFIC NW. BOTH THE ECMWF AND GFS SHOW
SOME SUBTROPICAL MOISTURE EMBEDDED IN THE FLOW WHICH WILL BE OVER
THE AREA BOTH DAYS. PRECIPITABLE WATER VALUES WILL BE IN THE 0.5-0.6
INCH RANGE OVER THE MTNS WITH VALUES FM 0.8-1.0 INCHES OVER THE
PLAINS. OVERALL WILL KEEP IN A SLIGHT CHC OF STORMS BOTH DAYS ACROSS
THE AREA. AS FOR HIGHS READINGS WILL REMAIN ABV NORMAL BOTH DAYS
WITH LOW TO MID 90S OVER NERN CO.
BY FRI LITTLE CHANGE IS EXPECTED AS AN UPPER LEVEL TROUGH REMAINS
OVER THE PACIFIC NW WITH SWLY FLOW ALOFT REMAINING OVER THE AREA
WITH SOME SUBTROPICAL MOISTURE STILL EMBEDDED IN THE FLOW.
PRECIPITABLE WATER VALUES INCREASE SLIGHTLY WITH 0.6-0.7 INCHES IN
THE MTNS WITH VALUES AOA AN INCH ACROSS THE PLAINS. THUS THERE MAY
BE SOME INCREASE IN COVERAGE FOR FRI AFTN INTO FRI EVENING. AS FOR
TEMPS READINGS WILL REMAIN ABV NORMAL OVER NERN CO WITH HIGHS IN THE
UPPER 80S TO LOWER 90S.
ON SAT THE UPPER LEVEL TROUGH WILL BEGIN TO SHIFT SLOWLY EASTWARD
WITH SWLY FLOW STILL OVER THE AREA. BOTH THE ECMWF AND GFS SHOW
SOME MID LVL DRYING BY AFTN ESPECIALLY IN THE MTNS AS PRECIPITABLE
WATER VALUES DROP BELOW 0.50 INCHES SO TSTM ACTIVITY SHOULD BE
LESS OVER THE HIGHER TERRAIN. OVER NERN CO PRECIPITABLE WATER
VALUES ARE STILL FCST TO BE AOA AN INCH. MEANWHILE THERE APPEARS
TO BE A WK BNDRY THAT WILL BE OVER NERN CO IN THE AFTN WHICH MAY
ACT AS A FOCUS FOR TSTM DEVELOPMENT. AS FOR HIGHS 850-700 MB TEMPS
DROP A FEW DEGREES SO WILL KEEP READINGS IN THE 80S OVER NERN CO.
BY SUN THE THE UPPER LEVEL TROUGH WILL MOVE INTO THE NRN ROCKIES
WITH WSW FLOW ALOFT OVER THE AREA. BOTH THE ECMWF AND GFS HAVE A
RATHER DRY AIRMASS OVER THE AREA WITH A SUBSTANTIAL DECREASE IN
PRECIPITABLE WATER VALUES. IF THIS IS THE CASE THEN ANY TSTM
ACTIVITY WILL BE PRETTY ISOLD AND CONFINED TO THE PLAINS. AS FOR
HIGHS READINGS WILL REMAIN ABV NORMAL WITH MID 80S TO LOWER 90S
ACROSS NERN CO.
ON MON THE FLOW ALOFT WILL REMAIN WSW AS A COOL FRONT IS SUPPOSED TO
MOVE ACROSS NERN CO...HOWEVER THE STRENGTH OF THIS FNT IS WEAKER
THAN WHAT THE MODELS SHOWED YESTERDAY. OVERALL THERE WILL BE
LIMITED MOISTURE SO WILL ONLY MENTION LOW POPS. HIGHS WILL DROP
BACK INTO THE UPPER 70S TO LOWER 80S OVER THE PLAINS.
&&
.AVIATION...(FOR THE TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 438 AM MDT TUE SEP 1 2015
NO AVIATION IMPACTS THROUGH THIS MORNING AND EARLY AFTERNOON AS
LIGHT SOUTHERLY WINDS PREVAIL. A WEAKLY ORGANIZED BAND OF SHOWERS
OR THUNDERSTORMS MAY DEVELOP THIS AFTERNOON AND MOVE ACROSS THE
DENVER AREA AIRPORTS. THE ABSENCE OF WINDS ALOFT SHOULD LEAD TO
RELATIVELY SLOW-MOVING STORMS WHICH COULD PRODUCE SOME MODERATE
RAINFALL...BUT NOT TOO MUCH IN THE WAY OF GUSTY WINDS.
THUNDERSTORM ACTIVITY IN THE DENVER AREA SHOULD OVER BY 7 OR 8 PM
MDT.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...DANKERS
LONG TERM...RPK
AVIATION...DANKERS
AREA FORECAST DISCUSSION
NWS MIAMI FL
754 PM EDT WED SEP 2 2015
.UPDATE...
SHOWERS AND THUNDERSTORMS CONTINUE TO WEAKEN ACROSS SOUTH FLORIDA
THIS EVENING...GIVING WAY TO PARTLY TO MOSTLY CLOUDY SKIES. MADE
ONLY MINOR ADJUSTMENTS TO THE ONGOING FORECAST TO ACCOUNT FOR THE
LATEST TRENDS.
&&
.PREV DISCUSSION... /ISSUED 353 PM EDT WED SEP 2 2015/
DISCUSSION...
ISOLATED TO SCATTERED THUNDERSTORMS CONTINUE ACROSS MAINLY THE
EAST COAST METRO AREAS WITH A RATHER WEAK EAST COAST SEA BREEZE.
OVER THE NEXT FEW HOURS...ADDITIONAL CONVECTION IS EXPECTED TO
DEVELOP MAINLY WEST OF THE EAST COAST METRO AREAS DUE TO
SUBSEQUENT OUTFLOW BOUNDARY INTERACTIONS. LATEST HRRR AGREES BY
PUSHING MOST OF THE LATER CONVECTION ACROSS THE NORTHWEST INTERIOR
THROUGH THE LATE AFTERNOON AND EARLY EVENING HOURS. MAIN THREATS
WITH THESE STORMS WILL BE FREQUENT LIGHTNING AND BRIEF HEAVY
DOWNPOURS.
UPPER RIDGING IS STILL EXPECTED TO BE THE MAIN WEATHER FEATURE
ACROSS SOUTH FLORIDA THROUGH THE REMAINDER OF THE WEEK AND INTO
THE FIRST PART OF THE WEEKEND. THIS WILL KEEP SURFACE WINDS AND
STEERING FLOW GENERALLY LIGHT WITH AFTERNOON AND EARLY EVENING
CONVECTION REMAINING MAINLY ACROSS THE INTERIOR.
BY LATE IN THE WEEKEND THROUGH THE EARLY PART OF NEXT WEEK...UPPER
RIDGING IS EXPECTED TO BREAK DOWN AS A BROAD H5 TROUGH DIGS
SOUTHWARD THROUGH THE FLORIDA PENINSULA AND INTO THE EASTERN GULF
OF MEXICO. THIS WILL USHER IN A MORE SOUTHWESTERLY MID LEVEL FLOW.
MODELS ALSO HINT AT SLIGHTLY DRIER AIR PUSHING INTO THE AREA
DURING THIS TIME FRAME WHICH WILL DO LITTLE MORE THAN DECREASE
POPS SLIGHTLY FOR THE EARLY TO MID WEEK TIME FRAME NEXT WEEK.
AVIATION...
CONVECTION IS EXPECTED TO STAY AWAY FROM THE EAST COAST SITES
THROUGH THE REMAINDER OF THE AFTERNOON. LATEST HRRR KEEPS
ADDITIONAL OUTFLOW BOUNDARY DRIVEN CONVECTION ACROSS THE INTERIOR
INTO THE EARLY EVENING HOURS...SOME POSSIBLY AFFECTING KAPF.
OTHERWISE...LIGHT SOUTH TO SOUTHEASTERLY FLOW TO PREVAIL.
MARINE...
RATHER TRANQUIL MARINE CONDITIONS ARE EXPECTED THROUGH THE NEXT
COUPLE OF DAYS WITH LIGHT EAST TO SOUTHEAST WIND OF LESS THAN 10 KNOTS
AND SEAS OF 2 FEET OR LESS ACROSS ALL WATERS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 77 92 77 92 / 10 30 30 50
FORT LAUDERDALE 79 91 78 92 / 10 30 30 60
MIAMI 78 92 78 93 / 10 30 30 60
NAPLES 78 90 78 90 / 10 30 10 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
UPDATE...10/CD
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
345 PM EDT TUE SEP 1 2015
.Near Term [Through Tonight]...
An elongated area of low pressure with a large area of convection is
evident on satellite and radar imagery this afternoon about 100
miles south of Tallahassee. Fortunately, this system is expected to
move inland late tonight into Wednesday morning before it has a
chance to develop further. Rain will be most likely across the
southeast big bend and just offshore through the remainder of this
afternoon and into the overnight hours. Overnight lows are expected
to be in the low to mid 70s across the area.
.Short Term [Wednesday Through Thursday Night]...
Above-average rain chances will persist through Wednesday, at least
across the FL Big Bend, south-central GA, and north FL, as the
remnants of Erika translate slowly northward. PoPs will range from
20% around Dothan and Panama City, where the airmass remains
considerably drier, to 70% around Valdosta, Madison, and Perry.
Scattered mainly afternoon and evening thunderstorms are expected
Thursday region-wide. Our PoP is 40% for much of the area, which is
only slightly above climo. This number may trend up a bit in
subsequent forecasts as there may be some additional Q-G forcing mid-
upper layer trough approaches from the west. Temperatures will be
seasonably warm this period, with highs in the lower 90s and lows in
the 70s.
.Long Term [Friday Through Tuesday]...
The 12z GFS and ECMWF are in better agreement than 24 hours ago, as
they forecast a broad area of lower 500 mb heights over our region
for much of this period. PoPs will be slightly above-average (40-
50%) through the weekend, then tail off a bit next week as slightly
drier air in the boundary layer advects into the region on the
western flank of a weak low pressure system off the Southeast coast.
Temperatures will remain near average, with lows in the 70s and
highs near 90.
&&
.Aviation...
[Through 18Z Wednesday] Scattered convection is expected to be
near VLD through the early evening hours, and a period of MVFR to
IFR conditions is possible there late tonight. Otherwise, mainly
VFR conditions are expected to prevail.
&&
.Marine...
We were fortunate enough to get a 1630 UTC ASCAT pass over our
marine area to augment our sparse observation network. The data
showed that the remnants of Erika, though weak in terms of pressure,
had a closed circulation with wind speeds at advisory levels across
portions of the northeast Gulf of Mexico. The 15 UTC HRRR appeared
to have the best handle on this system (based on its
initialization), so we weighted it more in our forecast for
overnight. Convection aside, we expect "exercise caution" winds in
Apalachee Bay tonight, then winds weakening Wednesday morning as the
center of the low moves inland. Afterwards, winds and seas will be
quite low.
&&
.Fire Weather...
Relative humidity values will remain in the upper 40s or higher
through Thursday. In addition, winds are forecast to remain less
than 10MPH and thus hazardous fire weather conditions are not
expected through Thursday.
&&
.Hydrology...
The heaviest and most organized rain is expected across portions of
the FL Big Bend from this evening through Wednesday. Rain amounts
will be around an inch east and south of Tallahassee, and less than
a quarter of an inch elsewhere. Isolated rain amounts up to 4 inches
are possible, which could cause localized flooding if it occurs in
the wrong place (i.e. urban areas, small streams, etc.). Our rivers
were all below their local action stages, and the latest hydrologic
ensembles forecast this to continue for the next several days.
&&
.Preliminary Point Temps/PoPs...
Tallahassee 74 91 74 93 75 / 50 60 30 40 30
Panama City 76 88 77 88 76 / 10 30 10 40 30
Dothan 73 93 73 92 73 / 0 20 10 40 30
Albany 74 92 74 93 74 / 10 40 10 40 20
Valdosta 73 90 73 92 74 / 40 70 30 40 30
Cross City 75 90 74 91 75 / 60 50 30 40 30
Apalachicola 75 89 77 90 77 / 40 40 20 40 30
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...HIGH RIP CURRENT RISK until Midnight EDT tonight FOR Coastal
Franklin.
GA...NONE.
AL...NONE.
GM...NONE.
&&
$$
NEAR TERM...DVD
SHORT TERM...FOURNIER
LONG TERM...FOURNIER
AVIATION...DVD
MARINE...FOURNIER
FIRE WEATHER...FIEUX
HYDROLOGY...FOURNIER
AREA FORECAST DISCUSSION
NWS LINCOLN IL
223 PM CDT TUE SEP 1 2015
.SHORT TERM...(TONIGHT)
ISSUED AT 223 PM CDT TUE SEP 1 2015
LAST OF THE MORNING THUNDERSTORMS EAST OF I-57 HAS FINALLY FADED
AWAY. LATEST WATER VAPOR IMAGERY SHOWS THE UPPER LOW NEAR
INDIANAPOLIS HAS MOVED ONLY SLIGHTLY NORTHEAST...SO SOME DEEPER
MOISTURE REMAINS IN PLACE ACROSS THE EASTERN CWA. NICE AREA OF
SUBSIDENCE SHOWN ON VISIBLE IMAGERY EXPANDING ACROSS NORTHEAST
ILLINOIS AND NORTHWEST INDIANA...ASSOCIATED WITH THE OUTFLOW FROM
THE MORNING CONVECTION...WITH SOME DIURNAL CUMULUS DEVELOPING TO THE
WEST. RADAR SHOWED A COUPLE CELLS TRYING TO FIRE ALONG THE
BOUNDARY... BUT THESE FADED OFF QUICKLY.
CURRENTLY THINK THAT ANY RESIDUAL SHOWERS THAT DO FORM WILL FADE
WITH SUNSET...SO WILL MAINTAIN THE DRY FORECAST FOR TONIGHT. HAVE
ALSO KEPT MENTION OF PATCHY FOG ALONG AND EAST OF I-57...AS THERE IS
NOW QUITE A BIT OF MOISTURE FROM THE EARLIER HEAVY RAINS AND A WEAK
WIND FLOW AT THE SURFACE. WINDS JUST OFF THE DECK PROGGED TO 15-20
KNOT RANGE...SO ANY FOG SHOULD BE RATHER SHALLOW. TEMPERATURES
EXPECTED TO BE FAIRLY UNIFORM OVERNIGHT...MAINLY 67-70 DEGREES OVER
THE FORECAST AREA.
&&
.LONG TERM...(WEDNESDAY THROUGH TUESDAY)
ISSUED AT 223 PM CDT TUE SEP 1 2015
HIGH PRESSURE RIDGE WILL BUILD INTO THE PLAINS TOMORROW AND CONTINUE
THE HOT AND HUMID CONDITIONS THROUGH THE WEEK AND INTO THE WEEKEND.
WITH ALL MODELS FORECAST 850 TEMPS AROUND +18 TO +20C...AM EXPECTING
HIGHS TO BE AROUND 90S INTO THE LOWER 90S THROUGH THE REST OF THE
WEEK AND THROUGH THE WEEKEND...AND LIKELY INTO MONDAY...LABOR DAY.
CONDITIONS THROUGH THE PERIOD SHOULD BE DRY UNTIL LATE IN THE
WEEKEND AND EARLY NEXT WEEK. HOWEVER...THERE IS ONE PERIOD WHERE A
SHORT WAVE TROUGH IS FORECAST TO COME OVER THE TOP OF THE RIDGE WED
AND WED NIGHT THROUGH THE GREAT LAKES REGION INTO INDIANA. THIS
COULD BRING SOME QPF TO THE NORTHEASTERN PARTS OF THE STATE...WHICH
COULD EFFECT NORTHEASTERN AND EASTERN PARTS OF THE CWA. NAM
CONTINUES TO HAVE PCPN IN THE AREA BUT VARIES WITH THE
AMOUNTS...WHILE GFS BRINGS SOME IN BUT ALSO SEEMS TO OVERDO THE
AMOUNT OF QPF. 12Z ECMWF SEEMS MOST CONSISTENT WITH KEEPING PCPN TO
THE NORTH. FOR NOW WILL KEEP PCPN OUT OF THE CWA WED NIGHT AND THU
AND LET OVERNIGHT SHIFT TAKE A LOOK AFTER ANOTHER MODEL RUN.
THE NEXT CHANCE OF PCPN WILL THEN BE LATE IN THE WEEKEND AND THE
BEGINNING OF NEXT WEEK AND A STRONGER MID LEVEL LOW PRESSURE SYSTEM
FLATTENS THE RIDGE OUT AND TRYS TO DRAG A COLD FRONT INTO THE AREA.
MODELS DIFFER ON THE SFC SOLUTION THROUGH THE PERIOD BUT GFS AND
ECMWF DOES APPEAR TO BE IN BETTER AGREEMENT WITH SOME QPF MOVING
INTO THE AREA MONDAY. HOWEVER...THEY DO NOT AGREE WITH AMOUNTS AS
THE GFS WEAKENS THE SYSTEM AS IT MOVES INTO THE AREA. GIVEN THAT THE
PCPN WILL BE MOVING INTO A STRONG RIDGE...AM INCLINED TO LIMIT QPF
AND HAVE GONE WITH SLIGHT CHANCE FOR MON THROUGH MONDAY NIGHT. THIS
BOUNDARY DOES LOOK TO SAG SOUTH ENOUGH THAT MONDAY NIGHT AND TUE IT
LOOKS TO DEVELOP MORE PCPN THAT MOVES INTO THE AREA FOR TUESDAY.
TEMPS WILL FINALLY COOL AS WELL WITH MOST OF THE CWA BEING NORTH OF
THE BOUNDARY AND EFFECTED BY CLOUDS AND PCPN. HIGHS TUESDAY LOOK TO
HAVE COOLED DOWN INTO THE LOWER TO MIDDLE 80S...WITH UPPER 80S CLOSE
TO THE FRONT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1223 PM CDT TUE SEP 1 2015
LITTLE CHANGE NEEDED FROM PREVIOUS TAF SET. CONVECTION THAT
AFFECTED KCMI EARLIER HAS LARGELY FADED...BUT WILL MAINTAIN SOME
VCTS MENTION FOR A FEW MORE HOURS THERE AS THERE IS STILL SOME
ACTIVITY NEARBY. WELL DEFINED OUTFLOW BOUNDARY FROM THE EARLIER
STORMS IS EXTENDING NORTHWEST AND RECENTLY PASSED THROUGH
KBMI. HRRR MODEL HAS RECENTLY BEEN HINTING AT THIS AS A FOCUS FOR
ADDITIONAL CONVECTION OVER THE NEXT COUPLE HOURS...SO WILL MONITOR
THIS CLOSELY ALTHOUGH CONFIDENCE IS LOW ENOUGH TO PRECLUDE ANY
MENTION AT THIS TIME.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GEELHART
LONG TERM...AUTEN
AVIATION...GEELHART
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1223 PM CDT TUE SEP 1 2015
.UPDATE...
ISSUED AT 955 AM CDT TUE SEP 1 2015
WELL-DEFINED UPPER LOW...SEEN SPINNING NEAR INDIANAPOLIS THIS
MORNING...HAS PRODUCED THE THUNDERSTORMS THAT HAVE BEEN OCCURRING
BETWEEN I-57 AND THE INDIANA BORDER OVER THE LAST FEW HOURS.
SOUTHERN END OF THIS AREA SOUTH OF I-70 IS FINALLY FADING AFTER
PRODUCING AN ESTIMATED 4-7 INCHES OF RAIN...WHILE THE NORTHERN
FLANK ACROSS VERMILION COUNTY HAS SHOWN SOME UPTICK RECENTLY.
LATEST HRRR SHOWS A GENERAL DECREASING TREND OVER THE NEXT COUPLE
HOURS. HOWEVER...WITH THE LOW ONLY SLOWLY DRIFTING EAST TODAY...
SOME ADDITIONAL BUT MORE ISOLATED DEVELOPMENT IS POSSIBLE INTO THE
AFTERNOON.
ACROSS THE REMAINDER OF CENTRAL ILLINOIS...THE EXISTING FORECAST
WAS LARGELY ON TRACK. TEMPERATURES EXPECTED TO REACH INTO THE
LOWER 90S OVER THE WESTERN CWA...BUT WILL BE A BIT TRICKY IN THE
EAST DEPENDING ON HOW LONG THE CLOUD COVER LINGERS FROM THE
STORMS.
&&
.SHORT TERM...(TODAY)
ISSUED AT 315 AM CDT TUE SEP 1 2015
LATEST UPPER AIR ANALYSIS CONTINUES TO SHOW A LARGE RIDGE OF HIGH
PRESSURE EXTENDING FROM THE SOUTHERN PLAINS TO THE EASTERN GREAT
LAKES...HOWEVER A WEAKNESS IN THE RIDGE IS NOTED FROM INDIANA
SOUTHWESTWARD TO THE OZARKS. 07Z/2AM WATER VAPOR IMAGERY SHOWS A
VIGOROUS WAVE OVER NORTH-CENTRAL INDIANA...WHICH WILL LIKELY TRIGGER
SCATTERED SHOWERS AND THUNDERSTORMS ACROSS EAST-CENTRAL ILLINOIS
TODAY. MODELS DISAGREE ABOUT THE AREAL COVERAGE OF PRECIP...WITH
THE NAM KEEPING MOST OF IT ACROSS INDIANA. MEANWHILE...HIGHER-RES
MODELS SUCH AS THE RAPID REFRESH AND HRRR ARE QUITE AGGRESSIVE IN
DEVELOPING CONVECTION ACROSS THE E/SE KILX CWA OVER THE NEXT COUPLE
OF HOURS THEN LINGERING IT THROUGH EARLY AFTERNOON. GIVEN CURRENT
RADAR/SATELLITE TRENDS...THINK THIS MAY BE A BIT OVERDONE...HOWEVER
PRONOUNCED FEATURE ON WATER VAPOR IMAGERY DEFINITELY SUPPORTS POPS.
HAVE THEREFORE INCLUDED 20-30 POPS EAST OF I-55 TODAY AS THE WAVE
INTERACTS WITH A VERY WARM/HUMID AIRMASS. AFTERNOON HIGH
TEMPERATURES WILL BE COOLEST ACROSS THE EAST WHERE CLOUDS AND
SCATTERED THUNDERSTORMS WILL KEEP READINGS IN THE MIDDLE 80S.
FURTHER WEST ACROSS THE REMAINDER OF THE AREA...HIGHS WILL REACH THE
UPPER 80S TO AROUND 90 DEGREES.
.LONG TERM...(TONIGHT THROUGH MONDAY)
ISSUED AT 315 AM CDT TUE SEP 1 2015
INDIANA SHORT-WAVE WILL LIFT TO THE NORTHEAST ON WEDNESDAY...TAKING
ANY UPPER SUPPORT FOR CONVECTION INTO THE GREAT LAKES. AS A
RESULT...AM EXPECTING A HOT AND DRY DAY ACROSS THE BOARD WITH HIGH
TEMPERATURES CLIMBING INTO THE LOWER 90S. NEXT POTENTIAL FLY-IN-THE-
OINTMENT WILL BE A SECOND SHORT-WAVE TROUGH CURRENTLY EVIDENT ON
WATER VAPOR IMAGERY OVER WYOMING/COLORADO. THIS FEATURE WILL TRACK
INTO THE UPPER MIDWEST ON WEDNESDAY...THEN DROP E/SE INTO THE
EASTERN GREAT LAKES BY THURSDAY. 00Z SEP 1 NAM TAKES THE WAVE MUCH
FURTHER SOUTH AND GENERATES CONVECTION ACROSS NORTH-CENTRAL ILLINOIS
ON THURSDAY...HOWEVER THE NAM IS THE ODD MODEL OUT AS BOTH THE GFS
AND ECMWF KEEP IT FURTHER NORTH. WILL KEEP AN EYE ON THE TRACK OF
THE WAVE OVER THE NEXT 24-36 HOURS...BUT WILL FOLLOW THE GFS/ECMWF
CONSENSUS AND KEEP THURSDAY DRY FOR NOW.
THE PREVAILING UPPER RIDGE WILL CONTINUE TO BE THE DOMINANT WEATHER
FEATURE THROUGH THE WEEKEND...ENSURING A CONTINUATION OF VERY WARM
CONDITIONS WITH HIGHS IN THE LOWER 90S FRIDAY THROUGH SUNDAY. MAIN
QUESTION FOR EARLY NEXT WEEK WILL BE HOW QUICKLY THE RIDGE WILL
BREAK DOWN AS AN UPPER LOW APPROACHES FROM THE WEST. AS
EXPECTED...MODEL TRENDS HAVE BEEN SLOWER WITH THIS PROCESS...WITH
EVEN THE FASTER GFS SLOWING ITS SOLUTION TO LOOK MORE LIKE THE
ECMWF/GEM. THERE ARE EVEN SOME INDICATIONS THAT THE WESTERN UPPER
LOW WILL LIFT INTO SOUTHERN CANADA WHILE ITS ASSOCIATED COLD FRONT
DISSIPATES BEFORE PASSING THROUGH CENTRAL ILLINOIS. GFS CONTINUES
TO BE MORE AGGRESSIVE WITH FROPA LATE MONDAY INTO TUESDAY...HOWEVER
ECMWF SUGGESTS FRONT MAY ESSENTIALLY WASH OUT OVER CENTRAL ILLINOIS
TUESDAY. GIVEN BETTER MODEL CONSENSUS ON TIMING...HAVE REMOVED POPS
FROM SUNDAY AND SUNDAY NIGHT AND HAVE FOCUSED HIGHEST RAIN CHANCES
LATE MONDAY INTO TUESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1223 PM CDT TUE SEP 1 2015
LITTLE CHANGE NEEDED FROM PREVIOUS TAF SET. CONVECTION THAT
AFFECTED KCMI EARLIER HAS LARGELY FADED...BUT WILL MAINTAIN SOME
VCTS MENTION FOR A FEW MORE HOURS THERE AS THERE IS STILL SOME
ACTIVITY NEARBY. WELL DEFINED OUTFLOW BOUNDARY FROM THE EARLIER
STORMS IS EXTENDING NORTHWEST AND RECENTLY PASSED THROUGH
KBMI. HRRR MODEL HAS RECENTLY BEEN HINTING AT THIS AS A FOCUS FOR
ADDITIONAL CONVECTION OVER THE NEXT COUPLE HOURS...SO WILL MONITOR
THIS CLOSELY ALTHOUGH CONFIDENCE IS LOW ENOUGH TO PRECLUDE ANY
MENTION AT THIS TIME.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEELHART
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...GEELHART
AREA FORECAST DISCUSSION
NWS LINCOLN IL
956 AM CDT TUE SEP 1 2015
.UPDATE...
ISSUED AT 955 AM CDT TUE SEP 1 2015
WELL-DEFINED UPPER LOW...SEEN SPINNING NEAR INDIANAPOLIS THIS
MORNING...HAS PRODUCED THE THUNDERSTORMS THAT HAVE BEEN OCCURRING
BETWEEN I-57 AND THE INDIANA BORDER OVER THE LAST FEW HOURS.
SOUTHERN END OF THIS AREA SOUTH OF I-70 IS FINALLY FADING AFTER
PRODUCING AN ESTIMATED 4-7 INCHES OF RAIN...WHILE THE NORTHERN
FLANK ACROSS VERMILION COUNTY HAS SHOWN SOME UPTICK RECENTLY.
LATEST HRRR SHOWS A GENERAL DECREASING TREND OVER THE NEXT COUPLE
HOURS. HOWEVER...WITH THE LOW ONLY SLOWLY DRIFTING EAST TODAY...
SOME ADDITIONAL BUT MORE ISOLATED DEVELOPMENT IS POSSIBLE INTO THE
AFTERNOON.
ACROSS THE REMAINDER OF CENTRAL ILLINOIS...THE EXISTING FORECAST
WAS LARGELY ON TRACK. TEMPERATURES EXPECTED TO REACH INTO THE
LOWER 90S OVER THE WESTERN CWA...BUT WILL BE A BIT TRICKY IN THE
EAST DEPENDING ON HOW LONG THE CLOUD COVER LINGERS FROM THE
STORMS.
&&
.SHORT TERM...(TODAY)
ISSUED AT 315 AM CDT TUE SEP 1 2015
LATEST UPPER AIR ANALYSIS CONTINUES TO SHOW A LARGE RIDGE OF HIGH
PRESSURE EXTENDING FROM THE SOUTHERN PLAINS TO THE EASTERN GREAT
LAKES...HOWEVER A WEAKNESS IN THE RIDGE IS NOTED FROM INDIANA
SOUTHWESTWARD TO THE OZARKS. 07Z/2AM WATER VAPOR IMAGERY SHOWS A
VIGOROUS WAVE OVER NORTH-CENTRAL INDIANA...WHICH WILL LIKELY TRIGGER
SCATTERED SHOWERS AND THUNDERSTORMS ACROSS EAST-CENTRAL ILLINOIS
TODAY. MODELS DISAGREE ABOUT THE AREAL COVERAGE OF PRECIP...WITH
THE NAM KEEPING MOST OF IT ACROSS INDIANA. MEANWHILE...HIGHER-RES
MODELS SUCH AS THE RAPID REFRESH AND HRRR ARE QUITE AGGRESSIVE IN
DEVELOPING CONVECTION ACROSS THE E/SE KILX CWA OVER THE NEXT COUPLE
OF HOURS THEN LINGERING IT THROUGH EARLY AFTERNOON. GIVEN CURRENT
RADAR/SATELLITE TRENDS...THINK THIS MAY BE A BIT OVERDONE...HOWEVER
PRONOUNCED FEATURE ON WATER VAPOR IMAGERY DEFINITELY SUPPORTS POPS.
HAVE THEREFORE INCLUDED 20-30 POPS EAST OF I-55 TODAY AS THE WAVE
INTERACTS WITH A VERY WARM/HUMID AIRMASS. AFTERNOON HIGH
TEMPERATURES WILL BE COOLEST ACROSS THE EAST WHERE CLOUDS AND
SCATTERED THUNDERSTORMS WILL KEEP READINGS IN THE MIDDLE 80S.
FURTHER WEST ACROSS THE REMAINDER OF THE AREA...HIGHS WILL REACH THE
UPPER 80S TO AROUND 90 DEGREES.
.LONG TERM...(TONIGHT THROUGH MONDAY)
ISSUED AT 315 AM CDT TUE SEP 1 2015
INDIANA SHORT-WAVE WILL LIFT TO THE NORTHEAST ON WEDNESDAY...TAKING
ANY UPPER SUPPORT FOR CONVECTION INTO THE GREAT LAKES. AS A
RESULT...AM EXPECTING A HOT AND DRY DAY ACROSS THE BOARD WITH HIGH
TEMPERATURES CLIMBING INTO THE LOWER 90S. NEXT POTENTIAL FLY-IN-THE-
OINTMENT WILL BE A SECOND SHORT-WAVE TROUGH CURRENTLY EVIDENT ON
WATER VAPOR IMAGERY OVER WYOMING/COLORADO. THIS FEATURE WILL TRACK
INTO THE UPPER MIDWEST ON WEDNESDAY...THEN DROP E/SE INTO THE
EASTERN GREAT LAKES BY THURSDAY. 00Z SEP 1 NAM TAKES THE WAVE MUCH
FURTHER SOUTH AND GENERATES CONVECTION ACROSS NORTH-CENTRAL ILLINOIS
ON THURSDAY...HOWEVER THE NAM IS THE ODD MODEL OUT AS BOTH THE GFS
AND ECMWF KEEP IT FURTHER NORTH. WILL KEEP AN EYE ON THE TRACK OF
THE WAVE OVER THE NEXT 24-36 HOURS...BUT WILL FOLLOW THE GFS/ECMWF
CONSENSUS AND KEEP THURSDAY DRY FOR NOW.
THE PREVAILING UPPER RIDGE WILL CONTINUE TO BE THE DOMINANT WEATHER
FEATURE THROUGH THE WEEKEND...ENSURING A CONTINUATION OF VERY WARM
CONDITIONS WITH HIGHS IN THE LOWER 90S FRIDAY THROUGH SUNDAY. MAIN
QUESTION FOR EARLY NEXT WEEK WILL BE HOW QUICKLY THE RIDGE WILL
BREAK DOWN AS AN UPPER LOW APPROACHES FROM THE WEST. AS
EXPECTED...MODEL TRENDS HAVE BEEN SLOWER WITH THIS PROCESS...WITH
EVEN THE FASTER GFS SLOWING ITS SOLUTION TO LOOK MORE LIKE THE
ECMWF/GEM. THERE ARE EVEN SOME INDICATIONS THAT THE WESTERN UPPER
LOW WILL LIFT INTO SOUTHERN CANADA WHILE ITS ASSOCIATED COLD FRONT
DISSIPATES BEFORE PASSING THROUGH CENTRAL ILLINOIS. GFS CONTINUES
TO BE MORE AGGRESSIVE WITH FROPA LATE MONDAY INTO TUESDAY...HOWEVER
ECMWF SUGGESTS FRONT MAY ESSENTIALLY WASH OUT OVER CENTRAL ILLINOIS
TUESDAY. GIVEN BETTER MODEL CONSENSUS ON TIMING...HAVE REMOVED POPS
FROM SUNDAY AND SUNDAY NIGHT AND HAVE FOCUSED HIGHEST RAIN CHANCES
LATE MONDAY INTO TUESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 652 AM CDT TUE SEP 1 2015
ASIDE FROM SOME EARLY MORNING FOG, AND LATE NIGHT FOG ONCE AGAIN
WEDNESDAY MORNING, PREDOMINANTLY VFR CONDITIONS ARE EXPECTED
ACROSS THE CENTRAL ILLINOIS TERMINALS THROUGH THE 12Z TAF VALID
TIME. CIGS ARE MOST LIKELY TODAY AT KCMI AND POSSIBLY KDEC/KBMI
WITH AN UPPER LEVEL DISTURBANCE IN THE VICINITY. THIS DISTURBANCE
WILL ALSO PRODUCE A FEW THUNDERSTORMS AT KCMI FOR THE NEXT FEW
HOURS AND POSSIBLY INTO THE AFTERNOON.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEELHART
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...BAK
AREA FORECAST DISCUSSION
NWS LINCOLN IL
657 AM CDT TUE SEP 1 2015
.SHORT TERM...(TODAY)
ISSUED AT 315 AM CDT TUE SEP 1 2015
LATEST UPPER AIR ANALYSIS CONTINUES TO SHOW A LARGE RIDGE OF HIGH
PRESSURE EXTENDING FROM THE SOUTHERN PLAINS TO THE EASTERN GREAT
LAKES...HOWEVER A WEAKNESS IN THE RIDGE IS NOTED FROM INDIANA
SOUTHWESTWARD TO THE OZARKS. 07Z/2AM WATER VAPOR IMAGERY SHOWS A
VIGOROUS WAVE OVER NORTH-CENTRAL INDIANA...WHICH WILL LIKELY TRIGGER
SCATTERED SHOWERS AND THUNDERSTORMS ACROSS EAST-CENTRAL ILLINOIS
TODAY. MODELS DISAGREE ABOUT THE AREAL COVERAGE OF PRECIP...WITH
THE NAM KEEPING MOST OF IT ACROSS INDIANA. MEANWHILE...HIGHER-RES
MODELS SUCH AS THE RAPID REFRESH AND HRRR ARE QUITE AGGRESSIVE IN
DEVELOPING CONVECTION ACROSS THE E/SE KILX CWA OVER THE NEXT COUPLE
OF HOURS THEN LINGERING IT THROUGH EARLY AFTERNOON. GIVEN CURRENT
RADAR/SATELLITE TRENDS...THINK THIS MAY BE A BIT OVERDONE...HOWEVER
PRONOUNCED FEATURE ON WATER VAPOR IMAGERY DEFINITELY SUPPORTS POPS.
HAVE THEREFORE INCLUDED 20-30 POPS EAST OF I-55 TODAY AS THE WAVE
INTERACTS WITH A VERY WARM/HUMID AIRMASS. AFTERNOON HIGH
TEMPERATURES WILL BE COOLEST ACROSS THE EAST WHERE CLOUDS AND
SCATTERED THUNDERSTORMS WILL KEEP READINGS IN THE MIDDLE 80S.
FURTHER WEST ACROSS THE REMAINDER OF THE AREA...HIGHS WILL REACH THE
UPPER 80S TO AROUND 90 DEGREES.
.LONG TERM...(TONIGHT THROUGH MONDAY)
ISSUED AT 315 AM CDT TUE SEP 1 2015
INDIANA SHORT-WAVE WILL LIFT TO THE NORTHEAST ON WEDNESDAY...TAKING
ANY UPPER SUPPORT FOR CONVECTION INTO THE GREAT LAKES. AS A
RESULT...AM EXPECTING A HOT AND DRY DAY ACROSS THE BOARD WITH HIGH
TEMPERATURES CLIMBING INTO THE LOWER 90S. NEXT POTENTIAL FLY-IN-THE-
OINTMENT WILL BE A SECOND SHORT-WAVE TROUGH CURRENTLY EVIDENT ON
WATER VAPOR IMAGERY OVER WYOMING/COLORADO. THIS FEATURE WILL TRACK
INTO THE UPPER MIDWEST ON WEDNESDAY...THEN DROP E/SE INTO THE
EASTERN GREAT LAKES BY THURSDAY. 00Z SEP 1 NAM TAKES THE WAVE MUCH
FURTHER SOUTH AND GENERATES CONVECTION ACROSS NORTH-CENTRAL ILLINOIS
ON THURSDAY...HOWEVER THE NAM IS THE ODD MODEL OUT AS BOTH THE GFS
AND ECMWF KEEP IT FURTHER NORTH. WILL KEEP AN EYE ON THE TRACK OF
THE WAVE OVER THE NEXT 24-36 HOURS...BUT WILL FOLLOW THE GFS/ECMWF
CONSENSUS AND KEEP THURSDAY DRY FOR NOW.
THE PREVAILING UPPER RIDGE WILL CONTINUE TO BE THE DOMINANT WEATHER
FEATURE THROUGH THE WEEKEND...ENSURING A CONTINUATION OF VERY WARM
CONDITIONS WITH HIGHS IN THE LOWER 90S FRIDAY THROUGH SUNDAY. MAIN
QUESTION FOR EARLY NEXT WEEK WILL BE HOW QUICKLY THE RIDGE WILL
BREAK DOWN AS AN UPPER LOW APPROACHES FROM THE WEST. AS
EXPECTED...MODEL TRENDS HAVE BEEN SLOWER WITH THIS PROCESS...WITH
EVEN THE FASTER GFS SLOWING ITS SOLUTION TO LOOK MORE LIKE THE
ECMWF/GEM. THERE ARE EVEN SOME INDICATIONS THAT THE WESTERN UPPER
LOW WILL LIFT INTO SOUTHERN CANADA WHILE ITS ASSOCIATED COLD FRONT
DISSIPATES BEFORE PASSING THROUGH CENTRAL ILLINOIS. GFS CONTINUES
TO BE MORE AGGRESSIVE WITH FROPA LATE MONDAY INTO TUESDAY...HOWEVER
ECMWF SUGGESTS FRONT MAY ESSENTIALLY WASH OUT OVER CENTRAL ILLINOIS
TUESDAY. GIVEN BETTER MODEL CONSENSUS ON TIMING...HAVE REMOVED POPS
FROM SUNDAY AND SUNDAY NIGHT AND HAVE FOCUSED HIGHEST RAIN CHANCES
LATE MONDAY INTO TUESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 652 AM CDT TUE SEP 1 2015
ASIDE FROM SOME EARLY MORNING FOG, AND LATE NIGHT FOG ONCE AGAIN
WEDNESDAY MORNING, PREDOMINANTLY VFR CONDTIONS ARE EXPECTED ACROSS
THE CENTRAL ILLINOIS TERMINALS THROUGH THE 12Z TAF VALID TIME.
CIGS ARE MOST LIKELY TODAY AT KCMI AND POSSIBLY KDEC/KBMI WITH AN
UPPER LEVEL DISTURBANCE IN THE VICINITY. THIS DISTURBANCE WILL
ALSO PRODUCE A FEW THUNDERSTORMS AT KCMI FOR THE NEXT FEW HOURS
AND POSSIBLY INTO THE AFTERNOON.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...BAK
AREA FORECAST DISCUSSION
NWS LINCOLN IL
315 AM CDT TUE SEP 1 2015
.SHORT TERM...(TODAY)
ISSUED AT 315 AM CDT TUE SEP 1 2015
LATEST UPPER AIR ANALYSIS CONTINUES TO SHOW A LARGE RIDGE OF HIGH
PRESSURE EXTENDING FROM THE SOUTHERN PLAINS TO THE EASTERN GREAT
LAKES...HOWEVER A WEAKNESS IN THE RIDGE IS NOTED FROM INDIANA
SOUTHWESTWARD TO THE OZARKS. 07Z/2AM WATER VAPOR IMAGERY SHOWS A
VIGOROUS WAVE OVER NORTH-CENTRAL INDIANA...WHICH WILL LIKELY TRIGGER
SCATTERED SHOWERS AND THUNDERSTORMS ACROSS EAST-CENTRAL ILLINOIS
TODAY. MODELS DISAGREE ABOUT THE AREAL COVERAGE OF PRECIP...WITH
THE NAM KEEPING MOST OF IT ACROSS INDIANA. MEANWHILE...HIGHER-RES
MODELS SUCH AS THE RAPID REFRESH AND HRRR ARE QUITE AGGRESSIVE IN
DEVELOPING CONVECTION ACROSS THE E/SE KILX CWA OVER THE NEXT COUPLE
OF HOURS THEN LINGERING IT THROUGH EARLY AFTERNOON. GIVEN CURRENT
RADAR/SATELLITE TRENDS...THINK THIS MAY BE A BIT OVERDONE...HOWEVER
PRONOUNCED FEATURE ON WATER VAPOR IMAGERY DEFINITELY SUPPORTS POPS.
HAVE THEREFORE INCLUDED 20-30 POPS EAST OF I-55 TODAY AS THE WAVE
INTERACTS WITH A VERY WARM/HUMID AIRMASS. AFTERNOON HIGH
TEMPERATURES WILL BE COOLEST ACROSS THE EAST WHERE CLOUDS AND
SCATTERED THUNDERSTORMS WILL KEEP READINGS IN THE MIDDLE 80S.
FURTHER WEST ACROSS THE REMAINDER OF THE AREA...HIGHS WILL REACH THE
UPPER 80S TO AROUND 90 DEGREES.
&&
.LONG TERM...(TONIGHT THROUGH MONDAY)
ISSUED AT 315 AM CDT TUE SEP 1 2015
INDIANA SHORT-WAVE WILL LIFT TO THE NORTHEAST ON WEDNESDAY...TAKING
ANY UPPER SUPPORT FOR CONVECTION INTO THE GREAT LAKES. AS A
RESULT...AM EXPECTING A HOT AND DRY DAY ACROSS THE BOARD WITH HIGH
TEMPERATURES CLIMBING INTO THE LOWER 90S. NEXT POTENTIAL FLY-IN-THE-
OINTMENT WILL BE A SECOND SHORT-WAVE TROUGH CURRENTLY EVIDENT ON
WATER VAPOR IMAGERY OVER WYOMING/COLORADO. THIS FEATURE WILL TRACK
INTO THE UPPER MIDWEST ON WEDNESDAY...THEN DROP E/SE INTO THE
EASTERN GREAT LAKES BY THURSDAY. 00Z SEP 1 NAM TAKES THE WAVE MUCH
FURTHER SOUTH AND GENERATES CONVECTION ACROSS NORTH-CENTRAL ILLINOIS
ON THURSDAY...HOWEVER THE NAM IS THE ODD MODEL OUT AS BOTH THE GFS
AND ECMWF KEEP IT FURTHER NORTH. WILL KEEP AN EYE ON THE TRACK OF
THE WAVE OVER THE NEXT 24-36 HOURS...BUT WILL FOLLOW THE GFS/ECMWF
CONSENSUS AND KEEP THURSDAY DRY FOR NOW.
THE PREVAILING UPPER RIDGE WILL CONTINUE TO BE THE DOMINANT WEATHER
FEATURE THROUGH THE WEEKEND...ENSURING A CONTINUATION OF VERY WARM
CONDITIONS WITH HIGHS IN THE LOWER 90S FRIDAY THROUGH SUNDAY. MAIN
QUESTION FOR EARLY NEXT WEEK WILL BE HOW QUICKLY THE RIDGE WILL
BREAK DOWN AS AN UPPER LOW APPROACHES FROM THE WEST. AS
EXPECTED...MODEL TRENDS HAVE BEEN SLOWER WITH THIS PROCESS...WITH
EVEN THE FASTER GFS SLOWING ITS SOLUTION TO LOOK MORE LIKE THE
ECMWF/GEM. THERE ARE EVEN SOME INDICATIONS THAT THE WESTERN UPPER
LOW WILL LIFT INTO SOUTHERN CANADA WHILE ITS ASSOCIATED COLD FRONT
DISSIPATES BEFORE PASSING THROUGH CENTRAL ILLINOIS. GFS CONTINUES
TO BE MORE AGGRESSIVE WITH FROPA LATE MONDAY INTO TUESDAY...HOWEVER
ECMWF SUGGESTS FRONT MAY ESSENTIALLY WASH OUT OVER CENTRAL ILLINOIS
TUESDAY. GIVEN BETTER MODEL CONSENSUS ON TIMING...HAVE REMOVED POPS
FROM SUNDAY AND SUNDAY NIGHT AND HAVE FOCUSED HIGHEST RAIN CHANCES
LATE MONDAY INTO TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1153 PM CDT MON AUG 31 2015
CLOUD COVER HAS NEARLY COMPLETELY DISSIPATED TOWARD 05Z, WITH NO
APPRECIABLE FOG OF NOTE IN ANY LOCAL OBSERVATIONS, OTHER THAN CMI
SHOWING 7SM AND DANVILLE 5SM BR. DEWPOINT DEPRESSIONS ARE RANGING
FROM 8 DEG AT SPI TO 2 AT BMI, WITH DNV AT 1. AREAS OF MVFR FOG
STILL APPEAR POSSIBLE, BUT HRRR HAS REDUCED THE AREAL COVERAGE OF
IFR FOG TO JUST PATCHY AREAS IN EAST CENTRAL IL. HAVE ALTERED THE
TEMPO GROUPS LATER TONIGHT TO BUMP UP VIS FROM 1 TO THE 3SM-4SM
RANGE. FORECAST SOUNDINGS ARE NOT SUPPORTIVE OF SIGNIFICANT FOG
LATER TONIGHT. THERE IS MORE SUPPORT FOR AREAS OF LOW CLOUDS TO
BUBBLE UP AND DRIFT AROUND UNDER WEAK STEERING WINDS.
AN UPPER LOW SPINNING OVER INDIANA WILL ONCE BE A FOCUS FOR SPOTTY
SHOWERS AND ISOLATED THUNDERSTORMS TOMORROW, MAINLY SOUTHEAST OF
CMI TO DEC. THE POTENTIAL FOR PRECIP AT OUR EASTERN TERMINALS IS
LOW ENOUGH TO NOT INCLUDE ANY VCTS WITH THIS TAF ISSUANCE. WILL
INCREASE VFR CLOUD COVER TO BKN040 AT CMI AND DEC.
WINDS WILL CONTINUE OUT OF THE SOUTH THE REST OF THE NIGHT, WITH
SPEEDS IN THE 5-7KT RANGE. AS WEAK HIGH PRESSURE SLIDES FARTHER
EAST OF IL TOMORROW, WINDS WILL BECOME MORE SOUTHWEST AT 10KT OR
LESS.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...SHIMON
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
219 AM CDT TUE SEP 1 2015
.UPDATE...
835 PM CDT
MADE A FEW TWEAKS TO GOING FORECAST TONIGHT AND TOMORROW.
EXPANSIVE MID AND UPPER RIDGING OVER THE EASTERN 2/3 OF THE CONUS
CAN CLEARLY BE SEEN ON EVENING W/V IMAGERY. THE SWIRL OVER CENTRAL
INDIANA IS AN UPPER LOW/VORTICITY CENTER TRAPPED IN THE WEAK FLOW
UNDER THE RIDGE. AT THE SURFACE...EXPANSIVE HIGH PRESSURE RIDGING
COVERS THE EASTERN HALF OF THE CONUS. LIGHT TO CALM WINDS AND
MOIST BOUNDARY LAYER WITH DIMINISHING T/TD SPREADS AS TEMPS SLOWLY
COOL COULD AGAIN SET THE STAGE FOR SOME PATCHY FOG. A FEW
LOCATIONS HAVE DROPPED TO 5 MILE VISIBILITY IN LIGHT FOG/HAZE. MOS
AND HI-RES GUIDANCE MUCH LESS BULLISH THAN PAST FEW NIGHTS WITH
FOG...SO CONFIDENCE IS LOWER IN THERE BEING ANY DENSE FOG BUT
CANNOT RULE IT OUT TOWARD DAYBREAK.
HAVE REMOVED SLIGHT POPS FROM FAR SOUTHEAST CWA/EAST CENTRAL IL
AND BENTON COUNTY INDIANA PRIOR TO DAYBREAK. RAP IS BULLISH IS
GENERATING CONVECTION FROM MEANDERING UPPER LOW...BUT SUSPECT 700
MB CAPPING WILL HOLD. SEVERAL MODELS INDICATE ISOLATED TO
SCATTERED CONVECTION ON WESTERN PERIPHERY OF UPPER LOW ON TUESDAY
WHERE THERE WILL BE LESS CAPPING. HAVE KEPT POPS IN 20 PERCENT
RANGE...BUT INDICATED ISOLATED TSRA WORDING EAST OF A FAIRBURY TO
MI CITY LINE DURING THE AFTERNOON. OTHER FOCUS WAS ON TEMPS AND
POTENTIAL FOR LAKE COOLING ALONG IL SHORE. ITS UNCERTAIN WHETHER
WILDFIRE SMOKE THAT RESULTED IN ANOTHER SPECTACULAR SUNSET WILL
KEEP TEMPS DOWN SOME TOMORROW...BUT CONSIDERING MANY LOCATIONS
STILL HIT UPPER 80S TODAY...THINKING THAT 24-26 CELSIUS 925 MB
TEMPS SHOULD YIELD UPPER 80S TO LOW 90S INLAND. SIGNIFICANT
THERMAL GRADIENT BETWEEN LAND AND NEARSHORE AND WEAK ENOUGH FLOW
ALOFT THROUGH EARLY-MID AFTERNOON SHOULD ENABLE SOUTH-SOUTHWEST
WINDS TO TURN SOUTHEAST ALONG IL SHORE/CHICAGO AND NORTH...AND
LIMIT HIGHS ALONG IMMEDIATE SHORE TO LOWER-MID 80S. THIS SCENARIO
WAS DEPICTED NICELY BY 18Z RUN OF OUR LOCAL 8KM WRF-ARW.
RC
&&
.SHORT TERM...
232 PM CDT
TONIGHT AND TUESDAY...PERSISTENT SURFACE RIDGING ACROSS THE
EASTERN CONUS GENERALLY IS MATCHED BY THE UPPER LEVEL PATTERN
EXCEPT FOR A WEAK CUTOFF SHORTWAVE CIRCULATION ALONG A TROUGH
RUNNING FROM THE OHIO VALLEY INTO THE WESTERN GULF. THIS UPPER
CIRCULATION IS QUITE EVIDENT IN THE WATER VAPOR SATELLITE CHANNEL
BUT IN TERMS OF CONVECTION IT HAS NOT BEEN VERY ACTIVE SO FAR
TODAY ASIDE FROM A BRIEF THUNDERSTORM CLUSTER ACROSS CENTRAL IL.
YESTERDAY SAW MORE WIDESPREAD ACTIVITY STRETCHING FROM OHIO INTO
CENTRAL TEXAS.
MODELS HAVE BEEN DRIFTING THIS TROUGH SLOWLY WESTWARD WHICH MATCHES
THE SATELLITE TRENDS AND LIGHTNING ACTIVITY. EARLY TOMORROW THIS
TROUGH LIKELY REACHES ITS WESTERNMOST POSITION BEFORE BEING PICKED
UP BY THE NORTHERN STREAM FLOW AND SLOWLY CARRIED OFF TO THE EAST.
THE QUESTION IS WHAT EFFECT IT WILL HAVE ON TSRA CHANCES LOCALLY
THROUGH THE NEXT 24 HOURS. ACTIVITY TODAY SEEMS TO BE MOST FAVORED
NEAR THE CENTER OF THE TROUGH ALONG THE LOW LEVEL INSTABILITY AXIS
AND WHERE UPPER LEVEL SUBSIDENCE AND THE RELATED CAPPING ARE
WEAKEST. FORECAST SOUNDINGS AND MIDLEVEL TEMPERATURES SUGGEST THE
CUTOFF LINE FOR THE BEST TSRA CHANCES TOMORROW MAY LIE NEAR OR OVER
THE LOCAL FORECAST AREA...WITH OUR SOUTHEASTERN COUNTIES ALONG THE
IL/IN LINE BEING MOST FAVORED. SOUNDINGS TOWARD THE CHICAGO METRO
AREA AND FARTHER NORTHWEST TOWARD RFD MAINTAIN SLIGHTLY STRONGER
SUBSIDENCE AND CAPPING ALOFT. FOR NOW WILL CARRY A SLIGHT CHANCE OF
TSRA FOR THE SOUTHEAST PORTION OF THE FORECAST AREA...MAINLY FOR THE
PEAK HEATING PERIOD TOMORROW AFTERNOON.
WITH ALL THIS RIDGING AND MOIST RETURN FLOW OUT OF THE
GULF...TEMPERATURES ARE LIKELY TO APPROACH AND IN A FEW LOCATIONS
EXCEED THE 90 DEGREE MARK TOMORROW. LOW LEVEL MIXING MAY LIMIT THE
HEAT INDEX VALUES TO THE MID 90S TOMORROW AFTERNOON...BUT REGARDLESS
IT WILL STILL BE A WARM AND HUMID FIRST DAY OF METEOROLOGICAL FALL
ABOUT 10 DEGREES ABOVE NORMAL HIGHS BUT STILL 10 DEGREES BELOW THE
RECORD HIGHS.
LENNING
&&
.LONG TERM...
232 PM CDT
TUESDAY NIGHT THROUGH FRIDAY...
GUIDANCE CONTINUES THE THEME OF UNSEASONABLE WARMTH FOR THE
REGION...AND MOST OF THE AREAS EAST OF THE ROCKIES. 500MB RIDGE
WILL BE STEADILY BUILDING OVERHEAD TUE NGT INTO WED. SOME OF THE
OPERATIONAL SOLUTIONS INDICATE THE LINGERING WEAK MID-LVL WAVE
PROGRESSING EAST THROUGH THE OHIO VALLEY THAT COULD GENERATE AN
ISOLATED SHOWER/THUNDERSTORM TUE NGT/WED...HOWEVER THE FORCING
LOOKS TO REMAIN VERY WEAK. SO HAVE MAINTAINED A DRY FORECAST WITH
HEIGHTS RISING OVERHEAD. THIS SHOULD AID IN KEEPING A LID ON
CONVECTIVE ACTIVITY FOR THE CWFA. THERMAL RIDGE WILL REMAIN OVER
THE FORECAST AREA WED/THUR...WITH HIGHS ABOVE CLIMO AT LEAST IN
THE UPR 80S TO PERHAPS ARND 90. LLVL MOISTURE WILL ALSO BE
PRESENT...WITH DEW POINTS IN THE MID/UPR 60S. THIS WILL CREATE
HUMID CONDITIONS WITH HEAT INDEX VALUES IN THE LOW/MID 90S.
OVERNIGHT LOWS WILL EQUALLY REMAIN MILD...WITH LOWS GENERALLY IN THE
MID/UPR 60S. DEPENDING ON OVERNIGHT CLOUD COVER...A FEW LOCATIONS
MAY REMAIN ARND 70. HAVE NOT INCLUDED A MENTION OF FOG IN THE
EXTENDED PERIODS...HOWEVER WITH THE LACK OF A STRONG GRADIENT AND
LIGHT WINDS OVERNIGHT PATCHY FOG OR HAZE MAY OCCUR.
LATER IN THE WEEK HEIGHTS SHOULD REMAIN OVER THE REGION KEEPING A
LOW CHANCE FOR ANY CONVECTION...AND LIKELY ONLY BEING DIURNALLY
DRIVEN. AFTERNOON LAKE BREEZES WILL BE POSSIBLE AS WELL...WHICH
COULD ALLOW SOME WEAK MESOSCALE FORCING TO HELP TOUCH OFF AN
ISOLATED AFTERNOON STORM OR TWO IN THE EXTENDED PERIODS.
SATURDAY THROUGH MONDAY... HEADING INTO THE HOLIDAY WEEKEND
ENSEMBLES CONTINUE THE THEME OF MID-LVL RIDGING OVER THE EASTERN
CONUS STRETCHING INTO EASTERN CANADA...WITH A TROUGH OVER THE
SOUTHWEST CONUS. SPREAD AMONGST ENSEMBLE MEMBERS IS MINIMAL...WHICH
WILL HELP WITH THE CONFIDENCE OF A CONTINUED UNSEASONABLY WARM
PERIOD INTO THE WEEKEND AND PERHAPS EARLY NEXT WEEK. THUS HAVE
HELD ONTO TEMPS IN THE MID/UPR 80S. THERE CONTINUES TO BE PERIODIC
CHANCES FOR SHOWERS AND THUNDERSTORMS.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* FOG DEVELOPMENT THIS MORNING.
RODRIGUEZ
//DISCUSSION...UPDATED 06Z...
OUTSIDE OF A FEW PASSING CLOUDS AROUND 4KFT...MOSTLY CLEAR SKIES
ARE IN PLACE THIS MORNING. MONITORING FOG POTENTIAL FOR THIS
MORNING WITH INCREASING COVERAGE BECOMING MORE PROBABLE OVER THE
NEXT FEW HOURS. DONT THINK VIS WILL FALL ANYWHERE NEAR THE
IFR/LIFR VIS FROM MONDAY MORNING...RATHER THINK VIS WILL LIKELY
STAY IN THE 2-5SM RANGE. AFTER FOG DISSIPATES LATER THIS
MORNING...VFR CONDITIONS WITH SOUTHWEST WINDS WILL BE IN PLACE
FOR THE REST OF THE DAY. WILL CONTINUE TO MONITOR POSSIBLE
ISOLATED SHOWER/THUNDERSTORM DEVELOPMENT LATER THIS AFTERNOON
ACROSS THE AREA. AT THIS TIME...THINK ANY DEVELOPMENT WILL STAY TO
THE SOUTH AND SOUTHEAST OF ALL THE TERMINALS. HOWEVER...SOME
GUIDANCE IS TRYING TO INCH THIS CLOSER TO THE TERMINALS. HAVE LEFT
OUT ANY MENTION OF PRECIP AT THIS TIME.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE WITH FOG/VIS TRENDS.
* HIGH CONFIDENCE WITH WIND SPEED/DIRECTION.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...VFR. WEST WINDS.
THURSDAY...SLT CHC TSRA. PRIMARILY VFR. SOUTHWEST WINDS BCMG
SOUTHEAST.
FRIDAY...SLT CHC TSRA. PRIMARILY VFR. SOUTH TO SOUTHEAST WINDS.
SATURDAY...VFR. SOUTH TO SOUTHEAST WINDS.
SUNDAY...SLT CHC TSRA. PRIMARILY VFR. SOUTH WINDS.
BMD
&&
.MARINE...
218 AM CDT
HIGH PRESSURE WILL CONTINUE TO BE A DOMINATE FEATURE ACROSS THE
EASTERN THIRD OF THE COUNTRY THIS WEEK...WHILE THE BULK OF ANY
SYSTEMS CONTINUE TO STAY AWAY FROM THE REGION. SOUTHERLY FLOW WILL
CONTINUE TODAY INTO TONIGHT...WITH WINDS TURNING MORE NORTHERLY AS
A WEAK BOUNDARY PUSHES ACROSS THE NORTHERN PORTION OF THE LAKE
LATE TONIGHT INTO WEDNESDAY. DESPITE THIS TURNING WIND
FIELD...SPEEDS LOOK TO REMAIN ON THE LIGHTER SIDE. WINDS WILL
RETURN TO MORE OF A SOUTHERLY DIRECTION BY THE END OF THE WORK
WEEK. FOG IS ONCE AGAIN PRESENT OVER THE OPEN WATERS EARLY THIS
MORNING AND AFFECTING PRIMARILY THE ILLINOIS NEARSHORE
WATERS...WITH DENSE FOG LIKELY. DENSE FOG ADVISORY WILL REMAIN
THROUGH THE MORNING...BUT WILL NEED TO MONITOR POSSIBLE EXTENSION
AND EXPANSION INTO THE REMAINING AREAS OF THE NEARSHORE WATERS.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...DENSE FOG ADVISORY...LMZ740-LMZ741-LMZ777-LMZ779 UNTIL 10 AM
TUESDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1247 AM CDT TUE SEP 1 2015
.UPDATE...
835 PM CDT
MADE A FEW TWEAKS TO GOING FORECAST TONIGHT AND TOMORROW.
EXPANSIVE MID AND UPPER RIDGING OVER THE EASTERN 2/3 OF THE CONUS
CAN CLEARLY BE SEEN ON EVENING W/V IMAGERY. THE SWIRL OVER CENTRAL
INDIANA IS AN UPPER LOW/VORTICITY CENTER TRAPPED IN THE WEAK FLOW
UNDER THE RIDGE. AT THE SURFACE...EXPANSIVE HIGH PRESSURE RIDGING
COVERS THE EASTERN HALF OF THE CONUS. LIGHT TO CALM WINDS AND
MOIST BOUNDARY LAYER WITH DIMINISHING T/TD SPREADS AS TEMPS SLOWLY
COOL COULD AGAIN SET THE STAGE FOR SOME PATCHY FOG. A FEW
LOCATIONS HAVE DROPPED TO 5 MILE VISIBILITY IN LIGHT FOG/HAZE. MOS
AND HI-RES GUIDANCE MUCH LESS BULLISH THAN PAST FEW NIGHTS WITH
FOG...SO CONFIDENCE IS LOWER IN THERE BEING ANY DENSE FOG BUT
CANNOT RULE IT OUT TOWARD DAYBREAK.
HAVE REMOVED SLIGHT POPS FROM FAR SOUTHEAST CWA/EAST CENTRAL IL
AND BENTON COUNTY INDIANA PRIOR TO DAYBREAK. RAP IS BULLISH IS
GENERATING CONVECTION FROM MEANDERING UPPER LOW...BUT SUSPECT 700
MB CAPPING WILL HOLD. SEVERAL MODELS INDICATE ISOLATED TO
SCATTERED CONVECTION ON WESTERN PERIPHERY OF UPPER LOW ON TUESDAY
WHERE THERE WILL BE LESS CAPPING. HAVE KEPT POPS IN 20 PERCENT
RANGE...BUT INDICATED ISOLATED TSRA WORDING EAST OF A FAIRBURY TO
MI CITY LINE DURING THE AFTERNOON. OTHER FOCUS WAS ON TEMPS AND
POTENTIAL FOR LAKE COOLING ALONG IL SHORE. ITS UNCERTAIN WHETHER
WILDFIRE SMOKE THAT RESULTED IN ANOTHER SPECTACULAR SUNSET WILL
KEEP TEMPS DOWN SOME TOMORROW...BUT CONSIDERING MANY LOCATIONS
STILL HIT UPPER 80S TODAY...THINKING THAT 24-26 CELSIUS 925 MB
TEMPS SHOULD YIELD UPPER 80S TO LOW 90S INLAND. SIGNIFICANT
THERMAL GRADIENT BETWEEN LAND AND NEARSHORE AND WEAK ENOUGH FLOW
ALOFT THROUGH EARLY-MID AFTERNOON SHOULD ENABLE SOUTH-SOUTHWEST
WINDS TO TURN SOUTHEAST ALONG IL SHORE/CHICAGO AND NORTH...AND
LIMIT HIGHS ALONG IMMEDIATE SHORE TO LOWER-MID 80S. THIS SCENARIO
WAS DEPICTED NICELY BY 18Z RUN OF OUR LOCAL 8KM WRF-ARW.
RC
&&
.SHORT TERM...
232 PM CDT
TONIGHT AND TUESDAY...PERSISTENT SURFACE RIDGING ACROSS THE
EASTERN CONUS GENERALLY IS MATCHED BY THE UPPER LEVEL PATTERN
EXCEPT FOR A WEAK CUTOFF SHORTWAVE CIRCULATION ALONG A TROUGH
RUNNING FROM THE OHIO VALLEY INTO THE WESTERN GULF. THIS UPPER
CIRCULATION IS QUITE EVIDENT IN THE WATER VAPOR SATELLITE CHANNEL
BUT IN TERMS OF CONVECTION IT HAS NOT BEEN VERY ACTIVE SO FAR
TODAY ASIDE FROM A BRIEF THUNDERSTORM CLUSTER ACROSS CENTRAL IL.
YESTERDAY SAW MORE WIDESPREAD ACTIVITY STRETCHING FROM OHIO INTO
CENTRAL TEXAS.
MODELS HAVE BEEN DRIFTING THIS TROUGH SLOWLY WESTWARD WHICH MATCHES
THE SATELLITE TRENDS AND LIGHTNING ACTIVITY. EARLY TOMORROW THIS
TROUGH LIKELY REACHES ITS WESTERNMOST POSITION BEFORE BEING PICKED
UP BY THE NORTHERN STREAM FLOW AND SLOWLY CARRIED OFF TO THE EAST.
THE QUESTION IS WHAT EFFECT IT WILL HAVE ON TSRA CHANCES LOCALLY
THROUGH THE NEXT 24 HOURS. ACTIVITY TODAY SEEMS TO BE MOST FAVORED
NEAR THE CENTER OF THE TROUGH ALONG THE LOW LEVEL INSTABILITY AXIS
AND WHERE UPPER LEVEL SUBSIDENCE AND THE RELATED CAPPING ARE
WEAKEST. FORECAST SOUNDINGS AND MIDLEVEL TEMPERATURES SUGGEST THE
CUTOFF LINE FOR THE BEST TSRA CHANCES TOMORROW MAY LIE NEAR OR OVER
THE LOCAL FORECAST AREA...WITH OUR SOUTHEASTERN COUNTIES ALONG THE
IL/IN LINE BEING MOST FAVORED. SOUNDINGS TOWARD THE CHICAGO METRO
AREA AND FARTHER NORTHWEST TOWARD RFD MAINTAIN SLIGHTLY STRONGER
SUBSIDENCE AND CAPPING ALOFT. FOR NOW WILL CARRY A SLIGHT CHANCE OF
TSRA FOR THE SOUTHEAST PORTION OF THE FORECAST AREA...MAINLY FOR THE
PEAK HEATING PERIOD TOMORROW AFTERNOON.
WITH ALL THIS RIDGING AND MOIST RETURN FLOW OUT OF THE
GULF...TEMPERATURES ARE LIKELY TO APPROACH AND IN A FEW LOCATIONS
EXCEED THE 90 DEGREE MARK TOMORROW. LOW LEVEL MIXING MAY LIMIT THE
HEAT INDEX VALUES TO THE MID 90S TOMORROW AFTERNOON...BUT REGARDLESS
IT WILL STILL BE A WARM AND HUMID FIRST DAY OF METEOROLOGICAL FALL
ABOUT 10 DEGREES ABOVE NORMAL HIGHS BUT STILL 10 DEGREES BELOW THE
RECORD HIGHS.
LENNING
&&
.LONG TERM...
232 PM CDT
TUESDAY NIGHT THROUGH FRIDAY...
GUIDANCE CONTINUES THE THEME OF UNSEASONABLE WARMTH FOR THE
REGION...AND MOST OF THE AREAS EAST OF THE ROCKIES. 500MB RIDGE
WILL BE STEADILY BUILDING OVERHEAD TUE NGT INTO WED. SOME OF THE
OPERATIONAL SOLUTIONS INDICATE THE LINGERING WEAK MID-LVL WAVE
PROGRESSING EAST THROUGH THE OHIO VALLEY THAT COULD GENERATE AN
ISOLATED SHOWER/THUNDERSTORM TUE NGT/WED...HOWEVER THE FORCING
LOOKS TO REMAIN VERY WEAK. SO HAVE MAINTAINED A DRY FORECAST WITH
HEIGHTS RISING OVERHEAD. THIS SHOULD AID IN KEEPING A LID ON
CONVECTIVE ACTIVITY FOR THE CWFA. THERMAL RIDGE WILL REMAIN OVER
THE FORECAST AREA WED/THUR...WITH HIGHS ABOVE CLIMO AT LEAST IN
THE UPR 80S TO PERHAPS ARND 90. LLVL MOISTURE WILL ALSO BE
PRESENT...WITH DEW POINTS IN THE MID/UPR 60S. THIS WILL CREATE
HUMID CONDITIONS WITH HEAT INDEX VALUES IN THE LOW/MID 90S.
OVERNIGHT LOWS WILL EQUALLY REMAIN MILD...WITH LOWS GENERALLY IN THE
MID/UPR 60S. DEPENDING ON OVERNIGHT CLOUD COVER...A FEW LOCATIONS
MAY REMAIN ARND 70. HAVE NOT INCLUDED A MENTION OF FOG IN THE
EXTENDED PERIODS...HOWEVER WITH THE LACK OF A STRONG GRADIENT AND
LIGHT WINDS OVERNIGHT PATCHY FOG OR HAZE MAY OCCUR.
LATER IN THE WEEK HEIGHTS SHOULD REMAIN OVER THE REGION KEEPING A
LOW CHANCE FOR ANY CONVECTION...AND LIKELY ONLY BEING DIURNALLY
DRIVEN. AFTERNOON LAKE BREEZES WILL BE POSSIBLE AS WELL...WHICH
COULD ALLOW SOME WEAK MESOSCALE FORCING TO HELP TOUCH OFF AN
ISOLATED AFTERNOON STORM OR TWO IN THE EXTENDED PERIODS.
SATURDAY THROUGH MONDAY... HEADING INTO THE HOLIDAY WEEKEND
ENSEMBLES CONTINUE THE THEME OF MID-LVL RIDGING OVER THE EASTERN
CONUS STRETCHING INTO EASTERN CANADA...WITH A TROUGH OVER THE
SOUTHWEST CONUS. SPREAD AMONGST ENSEMBLE MEMBERS IS MINIMAL...WHICH
WILL HELP WITH THE CONFIDENCE OF A CONTINUED UNSEASONABLY WARM
PERIOD INTO THE WEEKEND AND PERHAPS EARLY NEXT WEEK. THUS HAVE
HELD ONTO TEMPS IN THE MID/UPR 80S. THERE CONTINUES TO BE PERIODIC
CHANCES FOR SHOWERS AND THUNDERSTORMS.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* FOG DEVELOPMENT THIS MORNING.
RODRIGUEZ
//DISCUSSION...UPDATED 06Z...
OUTSIDE OF A FEW PASSING CLOUDS AROUND 4KFT...MOSTLY CLEAR SKIES
ARE IN PLACE THIS MORNING. MONITORING FOG POTENTIAL FOR THIS
MORNING WITH INCREASING COVERAGE BECOMING MORE PROBABLE OVER THE
NEXT FEW HOURS. DONT THINK VIS WILL FALL ANYWHERE NEAR THE
IFR/LIFR VIS FROM MONDAY MORNING...RATHER THINK VIS WILL LIKELY
STAY IN THE 2-5SM RANGE. AFTER FOG DISSIPATES LATER THIS
MORNING...VFR CONDITIONS WITH SOUTHWEST WINDS WILL BE IN PLACE
FOR THE REST OF THE DAY. WILL CONTINUE TO MONITOR POSSIBLE
ISOLATED SHOWER/THUNDERSTORM DEVELOPMENT LATER THIS AFTERNOON
ACROSS THE AREA. AT THIS TIME...THINK ANY DEVELOPMENT WILL STAY TO
THE SOUTH AND SOUTHEAST OF ALL THE TERMINALS. HOWEVER...SOME
GUIDANCE IS TRYING TO INCH THIS CLOSER TO THE TERMINALS. HAVE LEFT
OUT ANY MENTION OF PRECIP AT THIS TIME.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE WITH FOG/VIS TRENDS.
* HIGH CONFIDENCE WITH WIND SPEED/DIRECTION.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...VFR. WEST WINDS.
THURSDAY...SLT CHC TSRA. PRIMARILY VFR. SOUTHWEST WINDS BCMG
SOUTHEAST.
FRIDAY...SLT CHC TSRA. PRIMARILY VFR. SOUTH TO SOUTHEAST WINDS.
SATURDAY...VFR. SOUTH TO SOUTHEAST WINDS.
SUNDAY...SLT CHC TSRA. PRIMARILY VFR. SOUTH WINDS.
BMD
&&
.MARINE...
232 PM CDT
WEAK LOW PRESSURE OVER MANITOBA WILL MOVE NORTHEAST
TOWARDS HUDSON BAY AND STRENGTHEN TUESDAY. THIS WILL INCREASE THE
GRADIENT FOR THE NORTHERN PORTIONS OF LAKE MICHIGAN LATE TONIGHT
INTO TUESDAY. OTHERWISE THE SOUTHERN HALF OF THE LAKE WILL CONTINUE
IN A SOUTHWEST TO SOUTH FLOW. THEN LARGE RIDGE OF HIGH PRESSURE WILL
REMAIN NEARLY STATIONARY THROUGH THE REMAINDER OF THE WEEK...WITH
GENERALLY SOUTHERLY WINDS.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...DENSE FOG ADVISORY...LMZ740-LMZ741-LMZ777-LMZ779 UNTIL 10 AM
TUESDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS LINCOLN IL
1153 PM CDT MON AUG 31 2015
.UPDATE...
ISSUED AT 900 PM CDT MON AUG 31 2015
SHOWERS HAVE ENDED THIS EVENING, WITH LINGERING PATCHES OF CLOUDS.
FORECAST SOUNDINGS ARE POINTING TOWARD A RESIDUAL LAYER OF
MOISTURE OVERNIGHT COULD LEAD TO SCATTERED CLOUDS FROM TIME TO
TIME, BUT NOTHING SIGNIFICANT. OF MORE CONCERN WILL BE THE
POTENTIAL FOR LOCALIZED DENSE FOG OVERNIGHT. DEWPOINTS REMAIN
QUITE HIGH, IN THE UPPER 60S TO LOW 70S. WITH MOSTLY CLEAR SKIES
AND LIGHT SOUTH WINDS OVER NIGHT, RADIATIONAL COOLING WILL HELP
DEWPOINT SPREADS DECREASE TO 0-2 DEGREES AFTER MIDNIGHT. WE
CONTINUED WITH FOG IN THE GRIDS FOR LATER TONIGHT INTO TOMORROW
MORNING. OVERALL, THE CURRENT FORECAST HAS THE EXPECTED TRENDS
COVERED WELL. NO FORMAL UPDATE WILL BE NEEDED THIS EVE.
&&
.SHORT TERM...(TONIGHT)
ISSUED AT 249 PM CDT MON AUG 31 2015
WEAK REMNANTS OF A BOUNDARY DRAPED OVER THE SOUTH AND A SMALL SFC
LOW OVER INDIANA ARE DOMINATING THE WEATHER THIS AFTERNOON FOR
CENTRAL ILLINOIS. YESTERDAY THE 70 DEGREE DEWPOINTS WERE CONFINED
TO RIGHT ALONG THE SFC BOUNDARY. TODAY, THEY ARE A LITTLE MORE
WIDESPREAD, EVEN THIS LATE IN THE DAY AS MIXING OUT HAS BEEN LIMITED
IN THE ALMOST STAGNANT AIRMASS. SOME OBS IN THE SOUTHEAST ARE
ACTUALLY DROPPING INTO THE UPPER 60S AFTER SOME WEAK CONVECTIVE
STORMS THIS MORNING. HOWEVER, QUITE LIKELY GOING TO SEE THOSE
DEWPOINTS REBOUND QUICKLY DUE TO A LOT OF QPF/MOISTURE IN THE SOIL.
WITH LIGHT SOUTHERLY WINDS AND VERY LITTLE IN THE WAY OF CLOUD COVER
EXPECTED TONIGHT, FOG IS ONCE AGAIN THE BIGGEST CONCERN. WITH SOME
MIXING STILL TO COME, HAVE LEFT THE FORECAST AS PATCHY FOR THE
ENTIRE CWA TONIGHT.
.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 249 PM CDT MON AUG 31 2015
MAIN WEATHER STORY THROUGH THE EXTENDED REMAINS THE VERY WARM AND
HUMID CONDITIONS THAT ARE EXPECTED TO PERSIST THROUGH THE WEEK AND
INTO THE WEEKEND. HIGH TEMPERATURES ON TUESDAY WILL REACH THE UPPER
80S TO AROUND 90 DEGREES...THEN READINGS WILL CLIMB INTO THE LOWER
90S FOR THE REMAINDER OF THE PERIOD. DRY WEATHER WILL GENERALLY BE
THE RULE...HOWEVER ISOLATED CONVECTION CANNOT BE RULED
OUT...ESPECIALLY TUESDAY AFTERNOON AS A WEAKNESS IN THE MEAN 500MB
RIDGE AXIS REMAINS IN THE VICINITY. MODELS CONTINUE TO SHOW SOME
CONVECTION ACROSS THE EASTERN PARTS OF THE CWA AS THIS FEATURE
GRADUALLY SHIFTS INTO THE GREAT LAKES BY WEDNESDAY.
THE NEXT SIGNIFICANT CHANCE FOR RAIN WILL NOT ARRIVE UNTIL EARLY
NEXT WEEK...WHEN A STRONG SHORT-WAVE FLATTENS THE UPPER RIDGE AND
PUSHES A COLD FRONT INTO THE REGION. MODELS ARE IN DISAGREEMENT
CONCERNING THE FRONT...WITH THE GFS NOW TRENDING SLOWER WITH THE
COLD FRONT PASSING THROUGH CENTRAL ILLINOIS LATE MONDAY NIGHT INTO
TUESDAY...WHILE THE ECMWF/GEM DOES NOT BRING THE COLD THROUGH THE
CWA AT ALL AND KEEPS THE RIDGE STRONG OVER THE AREA. GIVEN
PERSISTENT AND HIGHLY AMPLIFIED RIDGE POSITIONED ACROSS THE
MIDWEST...THINK A SLOWER BREAK DOWN TO THE PATTERN IS STILL BEST
SOLUTION. HAVE THEREFORE TRENDED SLOWER. AS A RESULT...AM
EXPECTING DRY CONDITIONS THROUGH SUNDAY NIGHT...WITH RAIN CHANCES
ARRIVING IN THE NORTHWEST MONDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1153 PM CDT MON AUG 31 2015
CLOUD COVER HAS NEARLY COMPLETELY DISSIPATED TOWARD 05Z, WITH NO
APPRECIABLE FOG OF NOTE IN ANY LOCAL OBSERVATIONS, OTHER THAN CMI
SHOWING 7SM AND DANVILLE 5SM BR. DEWPOINT DEPRESSIONS ARE RANGING
FROM 8 DEG AT SPI TO 2 AT BMI, WITH DNV AT 1. AREAS OF MVFR FOG
STILL APPEAR POSSIBLE, BUT HRRR HAS REDUCED THE AREAL COVERAGE OF
IFR FOG TO JUST PATCHY AREAS IN EAST CENTRAL IL. HAVE ALTERED THE
TEMPO GROUPS LATER TONIGHT TO BUMP UP VIS FROM 1 TO THE 3SM-4SM
RANGE. FORECAST SOUNDINGS ARE NOT SUPPORTIVE OF SIGNIFICANT FOG
LATER TONIGHT. THERE IS MORE SUPPORT FOR AREAS OF LOW CLOUDS TO
BUBBLE UP AND DRIFT AROUND UNDER WEAK STEERING WINDS.
AN UPPER LOW SPINNING OVER INDIANA WILL ONCE BE A FOCUS FOR SPOTTY
SHOWERS AND ISOLATED THUNDERSTORMS TOMORROW, MAINLY SOUTHEAST OF
CMI TO DEC. THE POTENTIAL FOR PRECIP AT OUR EASTERN TERMINALS IS
LOW ENOUGH TO NOT INCLUDE ANY VCTS WITH THIS TAF ISSUANCE. WILL
INCREASE VFR CLOUD COVER TO BKN040 AT CMI AND DEC.
WINDS WILL CONTINUE OUT OF THE SOUTH THE REST OF THE NIGHT, WITH
SPEEDS IN THE 5-7KT RANGE. AS WEAK HIGH PRESSURE SLIDES FARTHER
EAST OF IL TOMORROW, WINDS WILL BECOME MORE SOUTHWEST AT 10KT OR
LESS.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SHIMON
SHORT TERM...HJS
LONG TERM...AUTEN
AVIATION...SHIMON
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
732 PM EDT WED SEP 2 2015
.SYNOPSIS...
ISSUED AT 140 PM EDT WED SEP 2 2015
ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED THIS EVENING. THERE
ARE ALSO SMALL CHANCES FOR STORMS DURING THE LATE AFTERNOONS AND
THE EARLY EVENINGS THE NEXT FEW DAYS AS WEAK UPPER LEVEL SYSTEMS
COMBINE WITH DAYTIME HEATING. OTHERWISE...VERY WARM AND HUMID
CONDITIONS WILL PERSIST THROUGH THE REST OF THE WEEK. HIGHS WILL
BE IN THE MID TO UPPER 80S. LOWS WILL BE IN THE MID TO UPPER 60S.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 413 PM EDT WED SEP 2 2015
A WEAK UPPER LEVEL SYSTEM MOVED THROUGH EARLIER THIS MORNING AND
DEPOSITED SOME OUTFLOW BOUNDARIES FROM EARLIER CONVECTION.
AFTERNOON HEATING HAD ALLOWED CAPES TO RISE TO BETWEEN 3000 AND
3500 J/KG ACCORDING TO STORM PREDICTION MESOSCALE ANALYSIS OF CAPE
VALUES. MID LEVEL LAPSE RATES BETWEEN 5.0 AND 5.5 C/KM WERE VERY
STABLE...AND LOW LEVEL WIND SHEAR WAS VERY LIMITED. EXPECT STORMS
LATE TODAY AND EARLY TONIGHT TO BE OF THE PULSE TYPE AND HIGHLY
DIURNAL WITH THIS ENVIRONMENT. WIND GUSTS AROUND 45 MPH OVER
NORTHWEST OHIO WERE REPORTED FROM EARLIER CONVECTION. GIVEN THE
LATEST SPC DOWNDRAFT CAPE VALUES BETWEEN 1100 AND 1400 J/KG...WIND
GUSTS TO 50 MPH ARE POSSIBLE THROUGH EARLY TONIGHT. OTHERWISE...
STORMS SHOULD DISSIPATE TONIGHT...AND THEN REDEVELOP THURSDAY AS
AN UPPER LEVEL SYSTEM MOVES INTO THE AREA. THE BEST CHANCE FOR
RAIN WILL BE LATE IN THE AFTERNOON WITH DAYTIME HEATING.
TEMPERATURES WILL RISE INTO THE 80S AGAIN THURSDAY.
&&
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 413 PM EDT WED SEP 2 2015
NO MAJOR SHIFTS IN THE WEATHER PATTERN INTO THE WEEKEND AS STRONG
HIGH PRESSURE WILL CONTROL THE REGION. AFTERNOON HIGHS WELL INTO
THE 80S COMBINED WITH DEWPOINTS IN THE MIDDLE 60S TO NEAR 70 WILL
SET THE STAGE FOR UNSTABLE CONDITIONS WITH LITTLE IN THE WAY TO
PREVENT CONVECTION FROM FIRING FRIDAY INTO SATURDAY. ALTHOUGH
THERE WON`T BE ANY CLEAR FORCING MECHANISM...THE RISK WILL
NONETHELESS BE THERE FOR HIT AND MISS SHOWERS OR STORMS. WILL
MAINTAIN THE AFTERNOON/EVE MENTION FOR THIS PERIOD.
MODELS ARE TRENDING TOWARDS A SLOWER ARRIVAL TO THE COOLER AND LESS
HUMID AIR INTO THE REGION AS THE FIRST WAVE SET TO APPROACH MONDAY
ESSENTIALLY HITS A BRICK WALL AND MOVES NORTHWEST OF THE REGION.
SHOWERS AND STORMS WILL LIKELY ACCOMPANY THIS FEATURE BUT HOW FAR
INTO THE AREA THEY WILL MAKE IT SEEMS MORE IN QUESTION. FOR
CONTINUITY SAKE WILL KEEP CHC POPS GOING WITH TRENDS POTENTIALLY
DICTATING LOWERING/REMOVAL IN LATER FORECASTS. MORE STOUT SYSTEM SET
TO MOVE IN BY WEDNESDAY WITH A DEEPER TROUGH AND BETTER CHANCE TO AT
LEAST DAMPEN THE RIDGE AND BRING SOMEWHAT BETTER CHANCES FOR SHOWERS
AND STORMS. WILL GO WITH CHC POPS FOR NOW. AS NOTED...COOLER WEATHER
WILL HOLD OFF TILL AT THE END OF THE PERIOD WITH CONTINUATION OF
ABOVE NORMAL TEMPS AND MUGGY CONDITIONS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 730 PM EDT WED SEP 2 2015
UPR LEVEL RIDGE REMAINS OVER THE AREA THIS EVE PROVIDING VFR
CONDITIONS. DIURNAL HEATING HAS RESULTED IN ISOLATED SHRA/TS OVER
NW AND NORTH CENTRAL INDIANA AND SWRN MICHIGAN EARLY THIS EVE.
DOUBT THESE WILL IMPACT KSBN BUT LATEST HRRR SUGGESTS SOME
POTENTIAL FOR FURTHER CONVECTION ALONG OUTFLOW BOUNDARIES OVER THE
NEXT FEW HOURS SO ADDED A VCTS AT KSBN THROUGH THIS EVE.
OTHERWISE VFR CONDITIONS SHOULD PREVAIL OVERNIGHT WITH JUST SOME
MVFR VSYBS IN BR DUE TO RADIATIONAL COOLING OF MOIST BOUNDARY
LAYER TOWARD DAYBREAK. GENERALLY VFR CONDITIONS EXPECTED THU...
HOWEVER A WK SHRTWV DROPPING SE ACROSS THE AREA SHOULD CAUSE SCT
AFTN TSRA WHICH COULD IMPACT THE TERMINALS.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...SKIPPER
SHORT TERM...SKIPPER
LONG TERM...FISHER
AVIATION...JT
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
236 PM EDT TUE SEP 1 2015
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 400 AM EDT TUE SEP 1 2015
A BROAD UPPER RIDGE OVER THE CENTRAL AND EASTERN U.S. WILL STRENGTHEN
NEXT SEVERAL DAYS AND THEN FLATTEN OUT SOME EARLY NEXT WEEK. EVEN
THOUGH HIGH PRESSURE SURFACE AND ALOFT COVERS MUCH OF THE REGION AN
UPPER DISTURBANCE OVER NORTH CENTRAL INDIANA MAY PRODUCE A CHANCE OF
THUNDERSTORMS LATER TODAY AND ACROSS FAR NORTHEAST SECTIONS TONIGHT AND
WEDNESDAY. ANOTHER UPPER LEVEL DISTURBANCE MAY PRODUCE A FEW THUNDERSTORMS
NORTH AND CENTRAL SECTIONS THURSDAY AND MOST AREAS NEXT MONDAY.
OTHERWISE...IT WILL BE MOSTLY DRY WITH ABOVE NORMAL TEMPERATURES THROUGH THE
UPCOMING WEEK.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 931 AM EDT TUE SEP 1 2015
1330Z UPDATE...LATEST UPDATE OF THE HRRR SHOWS THE SHOWERS AND
THUNDERSTORMS CURRENTLY OVER EASTERN ILLINOIS SLOWLY MOVING
EASTWARD AND INTO THE WESTERN COUNTIES OF CENTRAL INDIANA OVER THE
NEXT FEW HOURS. HAVE SOME DOUBTS AS TO WHETHER THAT MUCH
PRECIPITATION COVERAGE WILL MOVE THIS FAST INTO THE AREA SINCE THE
UPPER LOW WILL REMAIN FAIRLY STATIONARY THROUGH AT LEAST 00Z.
NEVERTHELESS...UPDATED POPS MAINLY ACROSS THE WEST TO INCREASE
POPS SLIGHTLY BASED ON THE LATEST RADAR TRENDS AND THE HRRR
ANALYSIS. MADE A FEW OTHER MINOR TWEAK TO OTHER WEATHER ELEMENTS
FOR THE REST OF TODAY BASED ON THE LATEST TRENDS. MORE HUMID
CONDITIONS WITH HIGHS IN THE MID TO UPPER 80S WILL PREVAIL ACROSS
THE FORECAST AREA FOR THIS AFTERNOON. PREVIOUS DISCUSSION FOLLOWS.
WATER VAPOR SATELLITE INDICATED A SMALL CLOSED UPPER LOW WAS
LOCATED BETWEEN INDIANAPOLIS AND LAFAYETTE. MOST MODELS INDICATE
MORE CONVECTION DEVELOPING LATER TODAY...HOWEVER THE RAPID REFRESH
INDICATES CONVECTION RAPIDLY DEVELOPING OVER WESTERN SECTIONS OF
CENTRAL INDIANA IN THE NEXT FEW HOURS. I HAVE NOT SEEN ANY
EVIDENCE OF THIS HAPPENING SO FAR AND WILL KEEP EVERYTHING DRY
THROUGH 12Z.
HOWEVER THE COMBINATION OF THE THIS CLOSED UPPER LOW AND DAY TIME HEATING WILL
CAUSE SCATTERED THUNDERSTORMS LATER TODAY. AS A RESULT WILL GO WITH CHANCE POPS
MOST AREAS TODAY AND SLIGHT CHANCE POPS ACROSS OUR SOUTHWEST.
WITH MORE CLOUDS LATER TODAY...TEMPERATURES SHOULD BE A DEGREE OR TWO COOLER THAN
WHAT THEY WERE YESTERDAY. WENT WITH HIGHS IN THE MIDDLE 80S OVER NORTHERN SECTIONS
AND THE UPPER 80S ACROSS OUR SOUTH.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
ISSUED AT 400 AM EDT TUE SEP 1 2015
MODELS DRIFT THIS UPPER DISTURBANCE EAST INTO OHIO TONIGHT AND
WEDNESDAY. THE NAM INDICATES QUITE A BIT OF CONVECTION ACROSS OUR NORTH
WHILE THE GFS SHOWS LITTLE. WITH LOSS OF DAYTIME HEATING...I DO NOT
EXPECT MUCH CONVECTION. BUT WILL MENTION SLIGHT CHANCE POPS ACROSS
OUR NORTH AND EAST CENTRAL SECTIONS TONIGHT.
MODELS INDICATE SOME CONVECTION MAINLY OHIO WEDNESDAY AND WILL CONTINUE
SLIGHT CHANCE POPS FAR NORTHEAST. OTHERWISE...THE BROAD UPPER RIDGE
SHOULD KEEP IT QUITE WARM AND DRY OVER THE REST OF THE REGION WEDNESDAY
AND WEDNESDAY NIGHT.
ANOTHER WEAK DISTURBANCE MAY PRODUCE A FEW THUNDERSTORMS OVER NORTHERN
INDIANA THURSDAY AFTERNOON. THE MAIN ISSUE WITH THIS FORECAST IS THAT
MODELS INDICATE SOME CONVECTION OVER THE NEXT SEVERAL DAYS. BUT IN MANY
CASES THEY SEEM TO BE OVER DOING THIS WITH THE BROAD UPPER RIDGE ACROSS
THE EASTERN U.S.
TEMPERATURES WILL REMAIN ABOVE NORMAL THROUGH THE SHORT TERM WITH HIGHS
IN THE MIDDLE TO UPPER 80S OVER MOST SECTIONS AND AROUND 90 IN THE SOUTHWEST.
LOWS WILL BE IN THE UPPER 60S TO AROUND 70. IN MOST CASES WENT CLOSE
TO A MOS BLEND ON TEMPERATURES.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
ISSUED AT 235 PM EDT TUE SEP 1 2015
UPPER RIDGING WILL BUILD OVER THE AREA THROUGH THE WEEKEND. BY
MONDAY THE UPPER RIDGE BEGINS TO FLATTEN AND THIS SHOULD ALLOW A
FRONT TO APPROACH THE AREA BETWEEN MONDAY AND TUESDAY. THIS WILL
BRING CHANCES FOR THUNDERSTORMS WITH IT. AT THIS POINT WITH THE
UPPER RIDGE STILL AROUND BUT JUST A LITTLE FLATTER WILL KEEP POPS IN
THE SLIGHT TO LOW CHANCE CATEGORIES. FOR TEMPERATURES SHOULD SEE
CONTINUED ABOVE NORMAL VALUES IN THE UPPER 80S TO LOWER 90S UNTIL
AFTER THE FRONTAL PASSAGE.
&&
.AVIATION /DISCUSSION FOR 011800Z TAF ISSUANCE/...
ISSUED AT 106 PM EDT TUE SEP 1 2015
WIDELY SCATTERED THUNDERSTORMS ARE STARTING TO DWINDLE TO THE WEST
OF THE SITES AND STARTING TO PICK UP TO THE EAST. DON/T EXPECT ANY
OF THESE TO HAPPEN DIRECTLY OVER A SITE AT THIS POINT SO WILL LEAVE
OUT OF THE TAFS. AT KIND THOUGH WILL INCLUDE A VCTS WITH THUNDER
OCCURRING JUST TO THE NORTH AND WILL CARRY THIS FOR AN HOUR OR
TWO. VFR CU EXPECTED AT THE SITES THROUGH THE REST OF THE
AFTERNOON. DURING THE OVERNIGHT THE UPPER WAVE FORCING THE
CONVECTION WILL MOVE OUT AND ALLOW FOR MORE HIGH PRESSURE TO BUILD
IN WITH NEAR CALM WINDS AND PATCHY FOG. FOR NOW WILL GO WITH MVFR
FOG BASED ON LACK OF GROUND MOISTURE AT THE TAF SITES AND SOME
MIXING LEFT AS THE WAVE MOVES OUT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMF/JH
NEAR TERM...SMF/JH
SHORT TERM...JH
LONG TERM....CP
AVIATION...CP
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
107 PM EDT TUE SEP 1 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 400 AM EDT TUE SEP 1 2015
A BROAD UPPER RIDGE OVER THE CENTRAL AND EASTERN U.S. WILL STRENGTHEN
NEXT SEVERAL DAYS AND THEN FLATTEN OUT SOME EARLY NEXT WEEK. EVEN
THOUGH HIGH PRESSURE SURFACE AND ALOFT COVERS MUCH OF THE REGION AN
UPPER DISTURBANCE OVER NORTH CENTRAL INDIANA MAY PRODUCE A CHANCE OF
THUNDERSTORMS LATER TODAY AND ACROSS FAR NORTHEAST SECTIONS TONIGHT AND
WEDNESDAY. ANOTHER UPPER LEVEL DISTURBANCE MAY PRODUCE A FEW THUNDERSTORMS
NORTH AND CENTRAL SECTIONS THURSDAY AND MOST AREAS NEXT MONDAY.
OTHERWISE...IT WILL BE MOSTLY DRY WITH ABOVE NORMAL TEMPERATURES THROUGH THE
UPCOMING WEEK.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 931 AM EDT TUE SEP 1 2015
1330Z UPDATE...LATEST UPDATE OF THE HRRR SHOWS THE SHOWERS AND
THUNDERSTORMS CURRENTLY OVER EASTERN ILLINOIS SLOWLY MOVING
EASTWARD AND INTO THE WESTERN COUNTIES OF CENTRAL INDIANA OVER THE
NEXT FEW HOURS. HAVE SOME DOUBTS AS TO WHETHER THAT MUCH
PRECIPITATION COVERAGE WILL MOVE THIS FAST INTO THE AREA SINCE THE
UPPER LOW WILL REMAIN FAIRLY STATIONARY THROUGH AT LEAST 00Z.
NEVERTHELESS...UPDATED POPS MAINLY ACROSS THE WEST TO INCREASE
POPS SLIGHTLY BASED ON THE LATEST RADAR TRENDS AND THE HRRR
ANALYSIS. MADE A FEW OTHER MINOR TWEAK TO OTHER WEATHER ELEMENTS
FOR THE REST OF TODAY BASED ON THE LATEST TRENDS. MORE HUMID
CONDITIONS WITH HIGHS IN THE MID TO UPPER 80S WILL PREVAIL ACROSS
THE FORECAST AREA FOR THIS AFTERNOON. PREVIOUS DISCUSSION FOLLOWS.
WATER VAPOR SATELLITE INDICATED A SMALL CLOSED UPPER LOW WAS
LOCATED BETWEEN INDIANAPOLIS AND LAFAYETTE. MOST MODELS INDICATE
MORE CONVECTION DEVELOPING LATER TODAY...HOWEVER THE RAPID REFRESH
INDICATES CONVECTION RAPIDLY DEVELOPING OVER WESTERN SECTIONS OF
CENTRAL INDIANA IN THE NEXT FEW HOURS. I HAVE NOT SEEN ANY
EVIDENCE OF THIS HAPPENING SO FAR AND WILL KEEP EVERYTHING DRY
THROUGH 12Z.
HOWEVER THE COMBINATION OF THE THIS CLOSED UPPER LOW AND DAY TIME HEATING WILL
CAUSE SCATTERED THUNDERSTORMS LATER TODAY. AS A RESULT WILL GO WITH CHANCE POPS
MOST AREAS TODAY AND SLIGHT CHANCE POPS ACROSS OUR SOUTHWEST.
WITH MORE CLOUDS LATER TODAY...TEMPERATURES SHOULD BE A DEGREE OR TWO COOLER THAN
WHAT THEY WERE YESTERDAY. WENT WITH HIGHS IN THE MIDDLE 80S OVER NORTHERN SECTIONS
AND THE UPPER 80S ACROSS OUR SOUTH.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
ISSUED AT 400 AM EDT TUE SEP 1 2015
MODELS DRIFT THIS UPPER DISTURBANCE EAST INTO OHIO TONIGHT AND
WEDNESDAY. THE NAM INDICATES QUITE A BIT OF CONVECTION ACROSS OUR NORTH
WHILE THE GFS SHOWS LITTLE. WITH LOSS OF DAYTIME HEATING...I DO NOT
EXPECT MUCH CONVECTION. BUT WILL MENTION SLIGHT CHANCE POPS ACROSS
OUR NORTH AND EAST CENTRAL SECTIONS TONIGHT.
MODELS INDICATE SOME CONVECTION MAINLY OHIO WEDNESDAY AND WILL CONTINUE
SLIGHT CHANCE POPS FAR NORTHEAST. OTHERWISE...THE BROAD UPPER RIDGE
SHOULD KEEP IT QUITE WARM AND DRY OVER THE REST OF THE REGION WEDNESDAY
AND WEDNESDAY NIGHT.
ANOTHER WEAK DISTURBANCE MAY PRODUCE A FEW THUNDERSTORMS OVER NORTHERN
INDIANA THURSDAY AFTERNOON. THE MAIN ISSUE WITH THIS FORECAST IS THAT
MODELS INDICATE SOME CONVECTION OVER THE NEXT SEVERAL DAYS. BUT IN MANY
CASES THEY SEEM TO BE OVER DOING THIS WITH THE BROAD UPPER RIDGE ACROSS
THE EASTERN U.S.
TEMPERATURES WILL REMAIN ABOVE NORMAL THROUGH THE SHORT TERM WITH HIGHS
IN THE MIDDLE TO UPPER 80S OVER MOST SECTIONS AND AROUND 90 IN THE SOUTHWEST.
LOWS WILL BE IN THE UPPER 60S TO AROUND 70. IN MOST CASES WENT CLOSE
TO A MOS BLEND ON TEMPERATURES.
&&
.LONG TERM /FRIDAY THROUGH NEXT MONDAY/...
ISSUED AT 400 AM EDT TUE SEP 1 2015
ENSEMBLES IN GOOD AGREEMENT IN KEEPING A LARGE UPPER RIDGE ACROSS THE
EASTERN PARTS OF THE COUNTRY THROUGH THE END OF THE WEEK. HOWEVER...THE
ENSEMBLES ALSO SUGGEST A WEAKNESS IN THE UPPER RIDGE MAY EXTEND FROM THE
OHIO VALLEY INTO THE SOUTHEAST PARTS OF THE COUNTRY DURING THAT TIME.
THIS MAY RESULT IN SOME POTENTIAL FOR MAINLY AFTERNOON AND EARLY EVENING
CONVECTION FROM FRIDAY THROUGH SUNDAY. OTHER THAT THE WEAKNESS ALOFT...THERE
IS NOT A STRONG SIGNAL FOR PRECIPITATION WITH HIGH PRESSURE GENERALLY IN
CONTROL. FOR THESE REASONS...WILL KEEP THE FRIDAY THROUGH SUNDAY PERIOD DRY.
BY EARLY NEXT WEEK...THE ENSEMBLES SUGGEST A DECENT SHORT WAVE TROUGH MAY
MOVE ACROSS THE NORTHERN PLAINS AND GREAT LAKES...WHICH MAY EVENTUALLY FLATTEN
THE RIDGE. AN ASSOCIATED FRONTAL SYSTEM MAY APPROACH THE LOCAL AREA BY THAT TIME.
WILL GO WITH CHANCE POPS FOR NEXT MONDAY.
TEMPERATURES SHOULD BE ABOVE NORMAL GIVEN THE PRESENCE OF THE UPPER RIDGE.
&&
.AVIATION /DISCUSSION FOR 011800Z TAF ISSUANCE/...
ISSUED AT 106 PM EDT TUE SEP 1 2015
WIDELY SCATTERED THUNDERSTORMS ARE STARTING TO DWINDLE TO THE WEST
OF THE SITES AND STARTING TO PICK UP TO THE EAST. DON/T EXPECT ANY
OF THESE TO HAPPEN DIRECTLY OVER A SITE AT THIS POINT SO WILL LEAVE
OUT OF THE TAFS. AT KIND THOUGH WILL INCLUDE A VCTS WITH THUNDER
OCCURRING JUST TO THE NORTH AND WILL CARRY THIS FOR AN HOUR OR
TWO. VFR CU EXPECTED AT THE SITES THROUGH THE REST OF THE
AFTERNOON. DURING THE OVERNIGHT THE UPPER WAVE FORCING THE
CONVECTION WILL MOVE OUT AND ALLOW FOR MORE HIGH PRESSURE TO BUILD
IN WITH NEAR CALM WINDS AND PATCHY FOG. FOR NOW WILL GO WITH MVFR
FOG BASED ON LACK OF GROUND MOISTURE AT THE TAF SITES AND SOME
MIXING LEFT AS THE WAVE MOVES OUT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMF/JH
NEAR TERM...SMF/JH
SHORT TERM...JH
LONG TERM...JAS
AVIATION...CP
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1025 AM EDT TUE SEP 1 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 400 AM EDT TUE SEP 1 2015
A BROAD UPPER RIDGE OVER THE CENTRAL AND EASTERN U.S. WILL STRENGTHEN
NEXT SEVERAL DAYS AND THEN FLATTEN OUT SOME EARLY NEXT WEEK. EVEN
THOUGH HIGH PRESSURE SURFACE AND ALOFT COVERS MUCH OF THE REGION AN
UPPER DISTURBANCE OVER NORTH CENTRAL INDIANA MAY PRODUCE A CHANCE OF
THUNDERSTORMS LATER TODAY AND ACROSS FAR NORTHEAST SECTIONS TONIGHT AND
WEDNESDAY. ANOTHER UPPER LEVEL DISTURBANCE MAY PRODUCE A FEW THUNDERSTORMS
NORTH AND CENTRAL SECTIONS THURSDAY AND MOST AREAS NEXT MONDAY.
OTHERWISE...IT WILL BE MOSTLY DRY WITH ABOVE NORMAL TEMPERATURES THROUGH THE
UPCOMING WEEK.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 931 AM EDT TUE SEP 1 2015
1330Z UPDATE...LATEST UPDATE OF THE HRRR SHOWS THE SHOWERS AND
THUNDERSTORMS CURRENTLY OVER EASTERN ILLINOIS SLOWLY MOVING
EASTWARD AND INTO THE WESTERN COUNTIES OF CENTRAL INDIANA OVER THE
NEXT FEW HOURS. HAVE SOME DOUBTS AS TO WHETHER THAT MUCH
PRECIPITATION COVERAGE WILL MOVE THIS FAST INTO THE AREA SINCE THE
UPPER LOW WILL REMAIN FAIRLY STATIONARY THROUGH AT LEAST 00Z.
NEVERTHELESS...UPDATED POPS MAINLY ACROSS THE WEST TO INCREASE
POPS SLIGHTLY BASED ON THE LATEST RADAR TRENDS AND THE HRRR
ANALYSIS. MADE A FEW OTHER MINOR TWEAK TO OTHER WEATHER ELEMENTS
FOR THE REST OF TODAY BASED ON THE LATEST TRENDS. MORE HUMID
CONDITIONS WITH HIGHS IN THE MID TO UPPER 80S WILL PREVAIL ACROSS
THE FORECAST AREA FOR THIS AFTERNOON. PREVIOUS DISCUSSION FOLLOWS.
WATER VAPOR SATELLITE INDICATED A SMALL CLOSED UPPER LOW WAS
LOCATED BETWEEN INDIANAPOLIS AND LAFAYETTE. MOST MODELS INDICATE
MORE CONVECTION DEVELOPING LATER TODAY...HOWEVER THE RAPID REFRESH
INDICATES CONVECTION RAPIDLY DEVELOPING OVER WESTERN SECTIONS OF
CENTRAL INDIANA IN THE NEXT FEW HOURS. I HAVE NOT SEEN ANY
EVIDENCE OF THIS HAPPENING SO FAR AND WILL KEEP EVERYTHING DRY
THROUGH 12Z.
HOWEVER THE COMBINATION OF THE THIS CLOSED UPPER LOW AND DAY TIME HEATING WILL
CAUSE SCATTERED THUNDERSTORMS LATER TODAY. AS A RESULT WILL GO WITH CHANCE POPS
MOST AREAS TODAY AND SLIGHT CHANCE POPS ACROSS OUR SOUTHWEST.
WITH MORE CLOUDS LATER TODAY...TEMPERATURES SHOULD BE A DEGREE OR TWO COOLER THAN
WHAT THEY WERE YESTERDAY. WENT WITH HIGHS IN THE MIDDLE 80S OVER NORTHERN SECTIONS
AND THE UPPER 80S ACROSS OUR SOUTH.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
ISSUED AT 400 AM EDT TUE SEP 1 2015
MODELS DRIFT THIS UPPER DISTURBANCE EAST INTO OHIO TONIGHT AND
WEDNESDAY. THE NAM INDICATES QUITE A BIT OF CONVECTION ACROSS OUR NORTH
WHILE THE GFS SHOWS LITTLE. WITH LOSS OF DAYTIME HEATING...I DO NOT
EXPECT MUCH CONVECTION. BUT WILL MENTION SLIGHT CHANCE POPS ACROSS
OUR NORTH AND EAST CENTRAL SECTIONS TONIGHT.
MODELS INDICATE SOME CONVECTION MAINLY OHIO WEDNESDAY AND WILL CONTINUE
SLIGHT CHANCE POPS FAR NORTHEAST. OTHERWISE...THE BROAD UPPER RIDGE
SHOULD KEEP IT QUITE WARM AND DRY OVER THE REST OF THE REGION WEDNESDAY
AND WEDNESDAY NIGHT.
ANOTHER WEAK DISTURBANCE MAY PRODUCE A FEW THUNDERSTORMS OVER NORTHERN
INDIANA THURSDAY AFTERNOON. THE MAIN ISSUE WITH THIS FORECAST IS THAT
MODELS INDICATE SOME CONVECTION OVER THE NEXT SEVERAL DAYS. BUT IN MANY
CASES THEY SEEM TO BE OVER DOING THIS WITH THE BROAD UPPER RIDGE ACROSS
THE EASTERN U.S.
TEMPERATURES WILL REMAIN ABOVE NORMAL THROUGH THE SHORT TERM WITH HIGHS
IN THE MIDDLE TO UPPER 80S OVER MOST SECTIONS AND AROUND 90 IN THE SOUTHWEST.
LOWS WILL BE IN THE UPPER 60S TO AROUND 70. IN MOST CASES WENT CLOSE
TO A MOS BLEND ON TEMPERATURES.
&&
.LONG TERM /FRIDAY THROUGH NEXT MONDAY/...
ISSUED AT 400 AM EDT TUE SEP 1 2015
ENSEMBLES IN GOOD AGREEMENT IN KEEPING A LARGE UPPER RIDGE ACROSS THE
EASTERN PARTS OF THE COUNTRY THROUGH THE END OF THE WEEK. HOWEVER...THE
ENSEMBLES ALSO SUGGEST A WEAKNESS IN THE UPPER RIDGE MAY EXTEND FROM THE
OHIO VALLEY INTO THE SOUTHEAST PARTS OF THE COUNTRY DURING THAT TIME.
THIS MAY RESULT IN SOME POTENTIAL FOR MAINLY AFTERNOON AND EARLY EVENING
CONVECTION FROM FRIDAY THROUGH SUNDAY. OTHER THAT THE WEAKNESS ALOFT...THERE
IS NOT A STRONG SIGNAL FOR PRECIPITATION WITH HIGH PRESSURE GENERALLY IN
CONTROL. FOR THESE REASONS...WILL KEEP THE FRIDAY THROUGH SUNDAY PERIOD DRY.
BY EARLY NEXT WEEK...THE ENSEMBLES SUGGEST A DECENT SHORT WAVE TROUGH MAY
MOVE ACROSS THE NORTHERN PLAINS AND GREAT LAKES...WHICH MAY EVENTUALLY FLATTEN
THE RIDGE. AN ASSOCIATED FRONTAL SYSTEM MAY APPROACH THE LOCAL AREA BY THAT TIME.
WILL GO WITH CHANCE POPS FOR NEXT MONDAY.
TEMPERATURES SHOULD BE ABOVE NORMAL GIVEN THE PRESENCE OF THE UPPER RIDGE.
&&
.AVIATION /DISCUSSION FOR THE 011500Z TAFS/...
ISSUED AT 1025 AM EDT TUE SEP 1 2015
SCATTERED CONVECTION OVER EASTERN ILLINOIS IS CREEPING INTO WESTERN
INDIANA. HOWEVER WITH THESE CELLS SHOWING ONLY VERY SLOW MOTION IF
ANY DO NOT EXPECT THEM TO OCCUR OVER THE SITES. HOWEVER KLAF AND
KHUF COULD SEE THUNDERSTORMS IN THE VICINITY BUT NOT OVERHEAD OVER
THE NEXT COUPLE OF HOURS. CB BASES THIS MORNING AROUND 050.
ADDITIONAL ISOLATED TO WIDELY SCATTERED CONVECTION MAY DEVELOP THIS
AFTERNOON AFTER 011800Z. CONFIDENCE IS LOW REGARDING THE COVERAGE/LOCATION
OF ANY CONVECTION LATER TODAY...SO WILL LEAVE THIS OUT OF THE FORECAST
FOR NOW. LOCALIZED IFR VISIBILITY RESTRICTIONS POSSIBLE IN HEAVIER
CONVECTIVE CELLS. CB BASES THIS AFTERNOON AROUND 030.
WINDS SHOULD BE FROM 220-240 DEGREES AT 7-10 KTS THROUGH THE DAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMF/JH
NEAR TERM...SMF/JH
SHORT TERM...JH
LONG TERM...JAS
AVIATION...JAS/CP
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
954 AM EDT TUE SEP 1 2015
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 400 AM EDT TUE SEP 1 2015
A BROAD UPPER RIDGE OVER THE CENTRAL AND EASTERN U.S. WILL STRENGTHEN
NEXT SEVERAL DAYS AND THEN FLATTEN OUT SOME EARLY NEXT WEEK. EVEN
THOUGH HIGH PRESSURE SURFACE AND ALOFT COVERS MUCH OF THE REGION AN
UPPER DISTURBANCE OVER NORTH CENTRAL INDIANA MAY PRODUCE A CHANCE OF
THUNDERSTORMS LATER TODAY AND ACROSS FAR NORTHEAST SECTIONS TONIGHT AND
WEDNESDAY. ANOTHER UPPER LEVEL DISTURBANCE MAY PRODUCE A FEW THUNDERSTORMS
NORTH AND CENTRAL SECTIONS THURSDAY AND MOST AREAS NEXT MONDAY.
OTHERWISE...IT WILL BE MOSTLY DRY WITH ABOVE NORMAL TEMPERATURES THROUGH THE
UPCOMING WEEK.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 931 AM EDT TUE SEP 1 2015
1330Z UPDATE...LATEST UPDATE OF THE HRRR SHOWS THE SHOWERS AND
THUNDERSTORMS CURRENTLY OVER EASTERN ILLINOIS SLOWLY MOVING
EASTWARD AND INTO THE WESTERN COUNTIES OF CENTRAL INDIANA OVER THE
NEXT FEW HOURS. HAVE SOME DOUBTS AS TO WHETHER THAT MUCH
PRECIPITATION COVERAGE WILL MOVE THIS FAST INTO THE AREA SINCE THE
UPPER LOW WILL REMAIN FAIRLY STATIONARY THROUGH AT LEAST 00Z.
NEVERTHELESS...UPDATED POPS MAINLY ACROSS THE WEST TO INCREASE
POPS SLIGHTLY BASED ON THE LATEST RADAR TRENDS AND THE HRRR
ANALYSIS. MADE A FEW OTHER MINOR TWEAK TO OTHER WEATHER ELEMENTS
FOR THE REST OF TODAY BASED ON THE LATEST TRENDS. MORE HUMID
CONDITIONS WITH HIGHS IN THE MID TO UPPER 80S WILL PREVAIL ACROSS
THE FORECAST AREA FOR THIS AFTERNOON. PREVIOUS DISCUSSION FOLLOWS.
WATER VAPOR SATELLITE INDICATED A SMALL CLOSED UPPER LOW WAS
LOCATED BETWEEN INDIANAPOLIS AND LAFAYETTE. MOST MODELS INDICATE
MORE CONVECTION DEVELOPING LATER TODAY...HOWEVER THE RAPID REFRESH
INDICATES CONVECTION RAPIDLY DEVELOPING OVER WESTERN SECTIONS OF
CENTRAL INDIANA IN THE NEXT FEW HOURS. I HAVE NOT SEEN ANY
EVIDENCE OF THIS HAPPENING SO FAR AND WILL KEEP EVERYTHING DRY
THROUGH 12Z.
HOWEVER THE COMBINATION OF THE THIS CLOSED UPPER LOW AND DAY TIME HEATING WILL
CAUSE SCATTERED THUNDERSTORMS LATER TODAY. AS A RESULT WILL GO WITH CHANCE POPS
MOST AREAS TODAY AND SLIGHT CHANCE POPS ACROSS OUR SOUTHWEST.
WITH MORE CLOUDS LATER TODAY...TEMPERATURES SHOULD BE A DEGREE OR TWO COOLER THAN
WHAT THEY WERE YESTERDAY. WENT WITH HIGHS IN THE MIDDLE 80S OVER NORTHERN SECTIONS
AND THE UPPER 80S ACROSS OUR SOUTH.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
ISSUED AT 400 AM EDT TUE SEP 1 2015
MODELS DRIFT THIS UPPER DISTURBANCE EAST INTO OHIO TONIGHT AND
WEDNESDAY. THE NAM INDICATES QUITE A BIT OF CONVECTION ACROSS OUR NORTH
WHILE THE GFS SHOWS LITTLE. WITH LOSS OF DAYTIME HEATING...I DO NOT
EXPECT MUCH CONVECTION. BUT WILL MENTION SLIGHT CHANCE POPS ACROSS
OUR NORTH AND EAST CENTRAL SECTIONS TONIGHT.
MODELS INDICATE SOME CONVECTION MAINLY OHIO WEDNESDAY AND WILL CONTINUE
SLIGHT CHANCE POPS FAR NORTHEAST. OTHERWISE...THE BROAD UPPER RIDGE
SHOULD KEEP IT QUITE WARM AND DRY OVER THE REST OF THE REGION WEDNEDAY
AND WEDNESDAY NIGHT.
ANOTHER WEAK DISTURBANCE MAY PRODUCE A FEW THUNDERSTORMS OVER NORTHERN
INDIANA THURSDAY AFTERNOON. THE MAIN ISSUE WITH THIS FORECAST IS THAT
MODELS INDICATE SOME CONVECTION OVER THE NEXT SEVERAL DAYS. BUT IN MANY
CASES THEY SEEM TO BE OVER DOING THIS WITH THE BROAD UPPER RIDGE ACROSS
THE EASTERN U.S.
TEMPERATURES WILL REMAIN ABOVE NORMAL THROUGH THE SHORT TERM WITH HIGHS
IN THE MIDDLE TO UPPER 80S OVER MOST SECTIONS AND AROUND 90 IN THE SOUTHWEST.
LOWS WILL BE IN THE UPPER 60S TO AROUND 70. IN MOST CASES WENT CLOSE
TO A MOS BLEND ON TEMPERATURES.
&&
.LONG TERM /FRIDAY THROUGH NEXT MONDAY/...
ISSUED AT 400 AM EDT TUE SEP 1 2015
ENSEMBLES IN GOOD AGREEMENT IN KEEPING A LARGE UPPER RIDGE ACROSS THE
EASTERN PARTS OF THE COUNTRY THROUGH THE END OF THE WEEK. HOWEVER...THE
ENSEMBLES ALSO SUGGEST A WEAKNESS IN THE UPPER RIDGE MAY EXTEND FROM THE
OHIO VALLEY INTO THE SOUTHEAST PARTS OF THE COUNTRY DURING THAT TIME.
THIS MAY RESULT IN SOME POTENTIAL FOR MAINLY AFTERNOON AND EARLY EVENING
CONVECTION FROM FRIDAY THROUGH SUNDAY. OTHER THAT THE WEAKNESS ALOFT...THERE
IS NOT A STRONG SIGNAL FOR PRECIPITATION WITH HIGH PRESSURE GENERALLY IN
CONTROL. FOR THESE REASONS...WILL KEEP THE FRIDAY THROUGH SUNDAY PERIOD DRY.
BY EARLY NEXT WEEK...THE ENSEMBLES SUGGEST A DECENT SHORT WAVE TROUGH MAY
MOVE ACROSS THE NORTHERN PLAINS AND GREAT LAKES...WHICH MAY EVENTUALLY FLATTEN
THE RIDGE. AN ASSOCIATED FRONTAL SYSTEM MAY APPROACH THE LOCAL AREA BY THAT TIME.
WILL GO WITH CHANCE POPS FOR NEXT MONDAY.
TEMPERATURES SHOULD BE ABOVE NORMAL GIVEN THE PRESENCE OF THE UPPER RIDGE.
&&
.AVIATION /DISCUSSION FOR THE 011200Z TAFS/...
ISSUED AT 632 AM EDT TUE SEP 1 2015
SCATTERED CONVECTION HAS BEEN DEVELOPING OVER THE PAST COUPLE OF HOURS
OVER EASTERN ILLINOIS...ASSOCIATED WITH A COLD POOL ALOFT. THESE CELLS
APPEAR TO BE DRIFTING OFF TO THE SOUTHEAST. SHORT TERM MODEL GUIDANCE
SUGGESTS THERE MAY BE ADDITIONAL DEVELOPMENT LATER THIS MORNING OVER
WEST CENTRAL INDIANA. MAY HAVE TO CARRY AT LEAST A CB SIGNIFICANT CLOUD
GROUP IN THE KHUF VICINITY THROUGH THE LATE MORNING HOURS IF CONVECTION
CONTINUES TO INCREASE IN COVERAGE. CB BASES THIS MORNING AROUND 050.
ADDITIONAL ISOLATED TO WIDELY SCATTERED CONVECTION MAY DEVELOP THIS
AFTERNOON AFTER 011800Z. CONFIDENCE IS LOW REGARDING THE COVERAGE/LOCATION
OF ANY CONVECTION LATER TODAY...SO WILL LEAVE THIS OUT OF THE FORECAST
FOR NOW. LOCALIZED IFR VISIBILITY RESTRICTIONS POSSIBLE IN HEAVIER
CONVECTIVE CELLS. CB BASES THIS AFTERNOON AROUND 030.
OTHERWISE...FOG HAS BEEN HELD IN CHECK SO FAR DUE TO THE DEVELOPING MID
LEVEL CLOUD. MAY STILL SEE A PERIOD AROUND SUNRISE OF IFR VISIBILITY
RESTRICITIONS AT THE TERMINALS...BUT THIS THREAT SEEMS TO BE DIMINISHING.
LIGHT SURFACE WINDS EARLY THIS MORNING EXPECTED TO BECOME 220-240 DEGREES
AT 7-10 KTS BY MIDDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMF/JH
NEAR TERM...SMF/JH
SHORT TERM...JH
LONG TERM...JAS
AVIATION...JAS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
621 PM CDT WED SEP 2 2015
...Update to aviation forecast discussion...
.SHORT TERM...(THIS EVENING THROUGH Thursday)
ISSUED AT 307 PM CDT WED SEP 2 2015
19z sfc map shows low pressure across the northern plains with a
trough extending south into western KS with most of eastern Kansas
now mixed out into the warm sector as remnants of elevated
convection wane. Water vapor loop shows a wave across Nebraska
moving E along the northern periphery of the upper ridge axis.
For tonight, the wave will track into northern MO overnight and may
help to enhance the LLJ which will contribute to modest WAA around
850mb. There is some additional WAA fcst to occur around the 700mb
level as well. Interesting that both the RAP and HRRR and GFS are
showing some small areas of QPF across central KS overnight despite
the 850mb thetae ridge remaining north of the CWA overnight. This
appears to be due to modest lift and saturation around 700-650mb
where even the NAM soundings show saturation after 6z. Fcst
soundings suggest modest elevated CAPE of 100j/kg or less. Other
convective models do not show this weak lift resulting in saturation
or convection so for now will keep the pops below 15 and keep the
fcst dry but something to watch for overnight.
We should see another day much like today on Thursday with 1000-
850mb thickness and temps nearly identical to today so will go with
persistence for temps. Pressure gradient is also similar so look for
another breezy day as well.
.LONG TERM...(Thursday NIGHT THROUGH Wednesday)
ISSUED AT 307 PM CDT WED SEP 2 2015
Thursday night through Saturday...Deep, moist southerly low-level
flow will continue through the period. With stronger south-
southwest flow aloft off to our west and northwest, no
recognizable dynamic feature is depicted in the short range
guidance to focus showers and thunderstorms in eastern KS. Only
possibility would be the remnants of some High Plains convective
cluster that might migrate into north central KS/south central/NE
before dissipating. Would expect any system like that to die out
before affecting our northwestern forecast area.
Saturday night through Wednesday...Strong upper trough over the
Rockies on Saturday evening will move northeast into southern
Manitoba and become an occluded system by Monday morning. While
strong dynamics are well to the north, southern extent of system
is a cold front that moves into central/eastern KS and then
becomes nearly stationary. This will be the focus for thunderstorm
chances late in the weekend into early next week. Medium range
models have some differences in the location of this boundary
already by Monday, but all depict it in the area with periodic
chances of thunderstorms into Tuesday night/Wednesday morning.
Then another strong trough moves across the central U.S. with the
result that the front pushes south of the area by late Wednesday.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z Thursday EVENING)
ISSUED AT 620 PM CDT WED SEP 2 2015
For the 00z TAFs, VFR conditions are expected through the period.
There is a slight chance for a few scattered showers and isolated
thunderstorms early Thursday morning, however confidence is not high
enough to mention in the TAFs at this time. Otherwise, southerly
winds will become more gusty Thursday afternoon.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Omitt
LONG TERM...GDP
AVIATION...Hennecke
AREA FORECAST DISCUSSION
NWS TOPEKA KS
349 PM CDT TUE SEP 1 2015
.SHORT TERM...(THIS EVENING THROUGH Wednesday)
ISSUED AT 339 PM CDT TUE SEP 1 2015
The upper levels show a broad upper ridge over the eastern CONUS
with a longwave trough just making its way into the Pacific
Northwest. Currently, most Radar sites across the Central Plains
remain quiet with only some rainshowers over southeastern South
Dakota. Cloud tops have progressively cooled throughout the day
indicating that storms have been dissipating. This area of showers
appears to be in advance of a mid to upper level low amplitude
shortwave that is showing signs of weakening with decreasing
vorticity as it lifts further to the northeast from the lee trough
region of the Rockies.
Daytime mixing has allowed for some gusty winds at the surface today
as we are still under plenty of sunshine over northeastern KS. This
is expected to continue until tonight as winds calm as we begin to
lose insolation and the source of heating at the surface. Still
expecting that the previously mentioned shortwave will have at least
minor impacts tonight over northcentral and northeastern KS tonight
into the early morning hours Wednesday. Most short-term high
resolution guidance, such as the HRRR and RAP, suggest that weak
insentropic lift at around 310K level and a little extra
enhancement from the LLJ around 850mb will help create some small
areas of precip. With at least some midlevel instability due to
the remnants of the shortwave, there could be some elevated
thunderstorms. It is possible with drier low-levels per NAM and
RAP soundings that there could be some areas of stronger winds
with the more enhanced areas of thunderstorms and precip.
Expecting that tomorrow will be similar to today. As the clouds
from over night clear, expect mixing to occur once again with
highs climbing into the low 90s. Depending on how many clouds
remain, temps may need to be revised up a bit. As for lows
tonight, do expect temps to reach lower 70s which is up a bit due
to the expected cloud cover overnight.
.LONG TERM...(Wednesday NIGHT THROUGH Tuesday)
ISSUED AT 339 PM CDT TUE SEP 1 2015
Wednesday night through Friday afternoon...More of the same sensible
weather with highs in the 90s and lows in the 70s. Plume of
moisture continues to move into the four corners and southern and
Central Rockies as the western trof absorbs tropical energy from
near Baja. Weak wave may generate some isolated overnight showers
or a storm northwest late Wednesday night into early Thursday
morning, otherwise the ridge noses northward and keeps most of the
area dry and warm for the mid term period.
Friday night through Tuesday...Friday night and Saturday look to
be dry, before chances for precipitation start to increase Sunday
through Tuesday. An upper level system moving over the NW CONUS
Saturday will progress east along with an associated cold front.
With southerly winds advecting ample moisture into the region and
an advancing cold front, expect showers and storms to develop in
NE Kansas mainly early Monday morning through Tuesday. Models also
seem to be in better agreement with this timing. Cooler
temperatures are expected as that front passes, with lows in the
mid 60s Monday night and highs topping out in the low 80s on
Tuesday.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z Wednesday AFTERNOON)
ISSUED AT 1220 PM CDT TUE SEP 1 2015
VFR conditions should continue over the next 24hrs. Gusty winds at
times this afternoon should calm near 00z time frame. Overnight,
there are some very small chances of showers and thunderstorms but
these should remain off to the North and West of the terminals.
LLWS may be a concern near 12z time mainly near KMHK, but didn`t
include in this TAF issuance due to low confidence in actually
meeting threshold values.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Drake
LONG TERM...67/Heller
AVIATION...Drake
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1230 PM CDT TUE SEP 1 2015
...Update to aviation forecast discussion...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 322 AM CDT TUE SEP 1 2015
A broad upper ridge extended from the southwest US, east-northeast
across the southern plans into the southern Great Lakes States. An
upper level trough was amplifying across the Pacific Northwest. IR
satellite imagery showed a band of mid-level moisture extending from
western Mexico, north-northeast across the NM into the central high
plains then northeast into the upper midwest along the western
periphery of the upper level ridge axis.
Early this morning a weak upper trough was lifting northeast across
northwest KS. The weak ascent combined with weak isentropic lift was
causing some elevated showers and thunderstorms from northwest KS
northward into western NE. The HRRR tries to move some elevated
showers towards north central KS this morning. However, as the
boundary layer mixes the isentropic lift should weaken enough that
these showers should dissipate.
The ARW run of the WRF model shows the weak H5 trough across
northwest KS slowly tracking east-northeast across north central KS
and central NE this afternoon. The ARW does show a few elevated
showers or storms developing across Republic and Cloud counties
after 21Z. I kept a 14 pop in for the far northwest counties in case
the ARW solution were to verify. Most of the area will see mostly
sunny skies though the mid-level moisture plume may shift east into
the western counties of the CWA which would increase the high and
mid level cloud cover this afternoon. Highs across north central KS
may only reach near 90 degrees with lower to mid 90s across the
remainder of the CWA.
Tonight, The NAM and GFS show a second minor H5 trough lifting
northeast across northwest KS into central NE, around periphery of
the broad upper ridge axis. Both models show some isentropic lift
developing after 3Z across the northern counties of the CWA and
combined with weak ascent ahead of the H5 trough there could be a few
elevated showers or thunderstorms. Forecast soundings show bases may
be around 10,000 feet with some weak upglide at the 310 theta
surface. An increasing LLJ may also help to provide some ascent for
parcels to reach their LFC during the late evening and early morning
hours of Wednesday across the western and northern counties of the
CWA.
Both the ARW and NMM WRF model solutions show no QPF developing
Tonight with the better ascent and isentropic lift shifting
northward across central NE. Due to the model solution discrepancies
I will only go with slight chance pops tonight for the western and
northern counties of the CWA. The best chances for elevated showers
and storms will be along the NE border. overnight lows will be
around 70.
.LONG TERM...(Wednesday THROUGH Monday)
ISSUED AT 322 AM CDT TUE SEP 1 2015
On Wednesday morning there will still be a slight chance of a
lingering shower or storm in north central KS as the mid-level
shortwave continues to track eastward over southern NE and northern
KS. Isentropic lift appears to be rather weak during this period,
but there may be additional lift from a weakening low-level jet that
veers over that area in the morning hours. Soundings show dry air in
the lower levels, which could enhance the downward momentum transfer
of the the low-level jet to the surface through evaporation. These
wind gusts would be sub-severe since the jet speeds are less than 40
mph. The remainder of the day should be dry with general subsidence
behind the departing shortwave. The surface pressure gradient is
forecast to increase across eastern KS through out the day so expect
wind speeds around 15 to 25 mph with gusts up to 30 mph. On Thursday
morning models are depicting a similar scenario for north central KS
although it is hard to discern any obvious shortwave in the models,
and the isentropic lift appears weak again. The pressure gradient
remains strong across the region so expect similar windy conditions
during the day Thursday. The pattern is not forecast to change much
with southwest flow aloft locked in place until next weekend. Later
this week a strong mid/upper level system will track over the
Pacific NW and eventually the northern Rockies. Long term models
lift the remaining energy from this wave over the northern plains
sometime early next week given some timing differences. This should
send a cold front towards the area bringing the better chances for
showers and storms. The GFS is the fastest and further east with the
track of the wave therefore advancing the front quicker. There could
be a brief slight cool down behind the front before the mid/upper
ridge builds back over the plains.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z Wednesday AFTERNOON)
ISSUED AT 1220 PM CDT TUE SEP 1 2015
VFR conditions should continue over the next 24hrs. Gusty winds at
times this afternoon should calm near 00z time frame. Overnight,
there are some very small chances of showers and thunderstorms but
these should remain off to the North and West of the terminals.
LLWS may be a concern near 12z time mainly near KMHK, but didn`t
include in this TAF issuance due to low confidence in actually
meeting threshold values.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Gargan
LONG TERM...Sanders
AVIATION...Drake
AREA FORECAST DISCUSSION
NWS TOPEKA KS
639 AM CDT TUE SEP 1 2015
...Update to aviation forecast discussion...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 322 AM CDT TUE SEP 1 2015
A broad upper ridge extended from the southwest US, east-northeast
across the southern plans into the southern Great Lakes States. An
upper level trough was amplifying across the Pacific Northwest. IR
satellite imagery showed a band of mid-level moisture extending from
western Mexico, north-northeast across the NM into the central high
plains then northeast into the upper midwest along the western
periphery of the upper level ridge axis.
Early this morning a weak upper trough was lifting northeast across
northwest KS. The weak ascent combined with weak isentropic lift was
causing some elevated showers and thunderstorms from northwest KS
northward into western NE. The HRRR tries to move some elevated
showers towards north central KS this morning. However, as the
boundary layer mixes the isentropic lift should weaken enough that
these showers should dissipate.
The ARW run of the WRF model shows the weak H5 trough across
northwest KS slowly tracking east-northeast across north central KS
and central NE this afternoon. The ARW does show a few elevated
showers or storms developing across Republic and Cloud counties
after 21Z. I kept a 14 pop in for the far northwest counties in case
the ARW solution were to verify. Most of the area will see mostly
sunny skies though the mid-level moisture plume may shift east into
the western counties of the CWA which would increase the high and
mid level cloud cover this afternoon. Highs across north central KS
may only reach near 90 degrees with lower to mid 90s across the
remainder of the CWA.
Tonight, The NAM and GFS show a second minor H5 trough lifting
northeast across northwest KS into central NE, around periphery of
the broad upper ridge axis. Both models show some isentropic lift
developing after 3Z across the northern counties of the CWA and
combined with weak ascent ahead of the H5 trough there could be a few
elevated showers or thunderstorms. Forecast soundings show bases may
be around 10,000 feet with some weak upglide at the 310 theta
surface. An increasing LLJ may also help to provide some ascent for
parcels to reach their LFC during the late evening and early morning
hours of Wednesday across the western and northern counties of the
CWA.
Both the ARW and NMM WRF model solutions show no QPF developing
Tonight with the better ascent and isentropic lift shifting
northward across central NE. Due to the model solution discrepancies
I will only go with slight chance pops tonight for the western and
northern counties of the CWA. The best chances for elevated showers
and storms will be along the NE border. overnight lows will be
around 70.
.LONG TERM...(Wednesday THROUGH Monday)
ISSUED AT 322 AM CDT TUE SEP 1 2015
On Wednesday morning there will still be a slight chance of a
lingering shower or storm in north central KS as the mid-level
shortwave continues to track eastward over southern NE and northern
KS. Isentropic lift appears to be rather weak during this period,
but there may be additional lift from a weakening low-level jet that
veers over that area in the morning hours. Soundings show dry air in
the lower levels, which could enhance the downward momentum transfer
of the the low-level jet to the surface through evaporation. These
wind gusts would be sub-severe since the jet speeds are less than 40
mph. The remainder of the day should be dry with general subsidence
behind the departing shortwave. The surface pressure gradient is
forecast to increase across eastern KS through out the day so expect
wind speeds around 15 to 25 mph with gusts up to 30 mph. On Thursday
morning models are depicting a similar scenario for north central KS
although it is hard to discern any obvious shortwave in the models,
and the isentropic lift appears weak again. The pressure gradient
remains strong across the region so expect similar windy conditions
during the day Thursday. The pattern is not forecast to change much
with southwest flow aloft locked in place until next weekend. Later
this week a strong mid/upper level system will track over the
Pacific NW and eventually the northern Rockies. Long term models
lift the remaining energy from this wave over the northern plains
sometime early next week given some timing differences. This should
send a cold front towards the area bringing the better chances for
showers and storms. The GFS is the fastest and further east with the
track of the wave therefore advancing the front quicker. There could
be a brief slight cool down behind the front before the mid/upper
ridge builds back over the plains.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z Wednesday MORNING)
ISSUED AT 636 AM CDT TUE SEP 1 2015
Expect VFR conditions at the terminals for the next 24 hours.
Low-level wind shear may reach LLWS criteria for a few hours at
KTOP and KMHK, given a 925MB LLJ of 35 to 40 KTS and light winds
at the surface. Once the sunrises deeper mixing should increase
surface winds from the south-southwest.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Gargan
LONG TERM...Sanders
AVIATION...Gargan
AREA FORECAST DISCUSSION
NWS TOPEKA KS
325 AM CDT TUE SEP 1 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 322 AM CDT TUE SEP 1 2015
A broad upper ridge extended from the southwest US, east-northeast
across the southern plans into the southern Great Lakes States. An
upper level trough was amplifying across the Pacific Northwest. IR
satellite imagery showed a band of mid-level moisture extending from
western Mexico, north-northeast across the NM into the central high
plains then northeast into the upper midwest along the western
periphery of the upper level ridge axis.
Early this morning a weak upper trough was lifting northeast across
northwest KS. The weak ascent combined with weak isentropic lift was
causing some elevated showers and thunderstorms from northwest KS
northward into western NE. The HRRR tries to move some elevated
showers towards north central KS this morning. However, as the
boundary layer mixes the isentropic lift should weaken enough that
these showers should dissipate.
The ARW run of the WRF model shows the weak H5 trough across
northwest KS slowly tracking east-northeast across north central KS
and central NE this afternoon. The ARW does show a few elevated
showers or storms developing across Republic and Cloud counties
after 21Z. I kept a 14 pop in for the far northwest counties in case
the ARW solution were to verify. Most of the area will see mostly
sunny skies though the mid-level moisture plume may shift east into
the western counties of the CWA which would increase the high and
mid level cloud cover this afternoon. Highs across north central KS
may only reach near 90 degrees with lower to mid 90s across the
remainder of the CWA.
Tonight, The NAM and GFS show a second minor H5 trough lifting
northeast across northwest KS into central NE, around periphery of
the broad upper ridge axis. Both models show some isentropic lift
developing after 3Z across the northern counties of the CWA and
combined with weak ascent ahead of the H5 trough there could be a few
elevated showers or thunderstorms. Forecast soundings show bases may
be around 10,000 feet with some weak upglide at the 310 theta
surface. An increasing LLJ may also help to provide some ascent for
parcels to reach their LFC during the late evening and early morning
hours of Wednesday across the western and northern counties of the
CWA.
Both the ARW and NMM WRF model solutions show no QPF developing
Tonight with the better ascent and isentropic lift shifting
northward across central NE. Due to the model solution discrepancies
I will only go with slight chance pops tonight for the western and
northern counties of the CWA. The best chances for elevated showers
and storms will be along the NE border. overnight lows will be
around 70.
.LONG TERM...(Wednesday THROUGH Monday)
ISSUED AT 322 AM CDT TUE SEP 1 2015
On Wednesday morning there will still be a slight chance of a
lingering shower or storm in north central KS as the mid-level
shortwave continues to track eastward over southern NE and northern
KS. Isentropic lift appears to be rather weak during this period,
but there may be additional lift from a weakening low-level jet that
veers over that area in the morning hours. Soundings show dry air in
the lower levels, which could enhance the downward momentum transfer
of the the low-level jet to the surface through evaporation. These
wind gusts would be sub-severe since the jet speeds are less than 40
mph. The remainder of the day should be dry with general subsidence
behind the departing shortwave. The surface pressure gradient is
forecast to increase across eastern KS through out the day so expect
wind speeds around 15 to 25 mph with gusts up to 30 mph. On Thursday
morning models are depicting a similar scenario for north central KS
although it is hard to discern any obvious shortwave in the models,
and the isentropic lift appears weak again. The pressure gradient
remains strong across the region so expect similar windy conditions
during the day Thursday. The pattern is not forecast to change much
with southwest flow aloft locked in place until next weekend. Later
this week a strong mid/upper level system will track over the
Pacific NW and eventually the northern Rockies. Long term models
lift the remaining energy from this wave over the northern plains
sometime early next week given some timing differences. This should
send a cold front towards the area bringing the better chances for
showers and storms. The GFS is the fastest and further east with the
track of the wave therefore advancing the front quicker. There could
be a brief slight cool down behind the front before the mid/upper
ridge builds back over the plains.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z Tuesday NIGHT)
ISSUED AT 1148 PM CDT MON AUG 31 2015
VFR conditions are expected through the period. Lower boundary
layer will remain mixed through sunrise so not expecting any
mist to form. Surface winds should average around 8kts through 14Z
with a gradual increase above the surface so not including any
LLWS at this time as low level jet will be stronger west of the
terminals. Winds increase to around 12kts by 16Z with gusts to
22kts, then decrease to around 8 kts after 00Z.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Gargan
LONG TERM...Sanders
AVIATION...53
AREA FORECAST DISCUSSION
NWS PADUCAH KY
611 PM CDT WED SEP 2 2015
.SHORT TERM...(This evening through Friday Night)
Issued at 218 PM CDT WED SEP 2 2015
Upper level disturbance in the lower Mississippi River Valley was
causing some isolated showers to our southwest this
afternoon...with a few cells getting fairly close to our SEMO
counties. The RUC and HRRR models seem to be overdone by showing
some activity developing over us this afternoon. Cu field looks
fairly shallow right now, but will continue to monitor for any
isolated development. The aforementioned upper level feature will
shift east tonight.
The 12Z model consensus continues to advertise high pressure at the
surface and aloft that will keep the area mainly dry through
Friday. The only exception to this may be on Thursday night into
Friday when some energy may drop south on the east side of the
upper high. Not every model is advertising any QPF and there
really isn`t too much moisture to work with other than a shallow
layer between 850-700mb. But an isolated or widely scattered storm
is possible. Too low of a probability to mention in the forecast
but would not be surprised to see a few cells out there.
Temperatures will remain above normal. Looks like low level temps
rise a degree or so for tomorrow and given the abundant
sunshine...believe we could be a tad warmer on Thursday. Some of the
guidance supports this notion as well. We could see temperatures
drop a degree or so in the eastern sections on Friday though as the
upper ridge breaks down a bit there. However, it will still be
fairly warm. Lower 90s for highs and upper 60s to around 70 degrees
for lows looks to be the norm for the next few days along with light
and variable winds.
.LONG TERM...(Saturday through Wednesday)
Issued at 218 PM CDT WED SEP 2 2015
Average confidence in the short term period due to model
differences, especially toward the end of the period. Very few
changes to the long term with not much to discuss.
At the beginning of the long term period, weak high pressure at the
surface and aloft will be the predominant features affecting our
CWA`s weather, therefore dry conditions are forecast for the first
couple of days.
Beyond that and through most of the long term period, the
development of weaknesses or slight shifting of the axis of the
aforementioned high pressure will make it possible for isolated to
scattered convection to pop up given the moisture and instability
already in place.
With the approach and passage of a cold front, precipitation chances
slowly increase and eventually overspread the entire CWA by the end
of the period.
Above normal temperatures at the beginning of the period will slowly
cool back to near normal readings by the end of the period.
&&
.AVIATION...
Issued at 610 PM CDT WED SEP 2 2015
With the exception of visibilities in the 06z-13z Thursday time
frame, VFR conditions will dominate the WFO PAH TAF locations
through 00z Friday. Diurnally induced local lift will provide the
scattered cloud cover between 4kft-7kft AGL across the TAF sites
during the day.
Given the sharp surface boundary gradient, dew and shallow fog
will again be possible tonight, mainly after 06z Thursday.
Addressed isolated LVIFR to LIFr visibilities beyond main MVFR
visibilities with a mention of MIFG overnight.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS PADUCAH KY
637 AM CDT TUE SEP 1 2015
.UPDATE...
Issued at 637 AM CDT TUE SEP 1 2015
The AVIATION section has been updated for the 12Z TAF issuance.
&&
.SHORT TERM...(Today through Thursday)
Issued at 321 AM CDT TUE SEP 1 2015
Beginning to see some mid-level clouds developing over the
northern half of the region, and the upper low shows up real nice
on water vapor imagery over east, central Indiana. Some patchy fog
has been reported at a few locations, but it has not been terribly
persistent. Will keep a mention of patchy fog over much of the
area for an hour or so after daybreak.
The HRRR indicates that there may be some shower and storm
activity with this cloud development over southern Illinois by
daybreak, but it quickly kills it off by late morning. The NMM and
ARW WRF runs develop some convection closer to the upper low
before daybreak and then build it south down the Wabash Valley and
then southwest through southern Illinois through the morning. This
seems most plausible, so used it as a guide for PoP placement
through the day.
Coverage is not expected to be too great, and it may not happen
at all, so kept pops at slight chances only. If the WRF runs are
right, there won`t be much left after 18Z, but will keep the
slight chances over southern Illinois and much of southeast
Missouri through the afternoon just to be safe. The remainder of
the short term portion of the forecast is dry, with high pressure
at the surface and aloft through the period.
Looking at temperatures, the GFS and ECMWF-based MOS guidance
seems too hot for highs today through Thursday, as they have been
for most of this Summer. The previous forecast had this well in
hand, so did not make much change at all. There will be a slight
warming trend through Thursday, but with the surface high centered
right over the area, a major warming trend is not likely.
.LONG TERM...(Thursday Night through Monday)
Issued at 321 AM CDT TUE SEP 1 2015
Hot and dry conditions are expected during the long-term period
beneath a large upper-level high. Very little difference in temps or
humidity is expected from day to day. Highs will generally be in the
lower half of the 90s...tho some of the more recent MOS suggests we
may test the mid 90s Friday and Saturday.
Given the easterly low level flow, dew points are not forecast to be
as high as previous heat waves this summer. Forecast dew points
through the long term will be from 65 to 70, which is rather low
compared to the 75 to 80 degree dew points earlier this summer. The
ground has become significantly drier since the July flooding
events, which supports a forecast of lower humidity levels. On the
other hand, lower humidity also supports higher temps during the
day.
Will need to keep an eye the the possibility of an easterly wave
moving west into the se U.S. toward the end of the long term. At
minimum, this wave could help to bring down temps a notch or two,
and could also bring a few showers to portions of the region, esp
wrn KY.
&&
.AVIATION...
Issued at 637 AM CDT TUE SEP 1 2015
With scattered mid clouds and an occasional breeze, fog
development was limited to MVFR levels only this morning. Will
leave a mention in for an hour at KCGI and KPAH. Isolated
thunderstorms may develop southward into the region this morning,
but it will most likely impact southern Illinois this morning
before dissipating this afternoon. Will not mention in any of the
TAFs at this time, but will monitor radar trends closely. Went on
the optimistic side with fog forecast for late tonight. Only
mention was MVFR at KCGI.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...DRS
SHORT TERM...DRS
LONG TERM...GM
AVIATION...DRS
AREA FORECAST DISCUSSION
NWS PADUCAH KY
321 AM CDT TUE SEP 1 2015
.SHORT TERM...(Today through Thursday)
Issued at 321 AM CDT TUE SEP 1 2015
Beginning to see some mid-level clouds developing over the
northern half of the region, and the upper low shows up real nice
on water vapor imagery over east, central Indiana. Some patchy fog
has been reported at a few locations, but it has not been terribly
persistent. Will keep a mention of patchy fog over much of the
area for an hour or so after daybreak.
The HRRR indicates that there may be some shower and storm
activity with this cloud development over southern Illinois by
daybreak, but it quickly kills it off by late morning. The NMM and
ARW WRF runs develop some convection closer to the upper low
before daybreak and then build it south down the Wabash Valley and
then southwest through southern Illinois through the morning. This
seems most plausible, so used it as a guide for PoP placement
through the day.
Coverage is not expected to be too great, and it may not happen
at all, so kept pops at slight chances only. If the WRF runs are
right, there won`t be much left after 18Z, but will keep the
slight chances over southern Illinois and much of southeast
Missouri through the afternoon just to be safe. The remainder of
the short term portion of the forecast is dry, with high pressure
at the surface and aloft through the period.
Looking at temperatures, the GFS and ECMWF-based MOS guidance
seems too hot for highs today through Thursday, as they have been
for most of this Summer. The previous forecast had this well in
hand, so did not make much change at all. There will be a slight
warming trend through Thursday, but with the surface high centered
right over the area, a major warming trend is not likely.
.LONG TERM...(Thursday Night through Monday)
Issued at 321 AM CDT TUE SEP 1 2015
Hot and dry conditions are expected during the long-term period
beneath a large upper-level high. Very little difference in temps or
humidity is expected from day to day. Highs will generally be in the
lower half of the 90s...tho some of the more recent MOS suggests we
may test the mid 90s Friday and Saturday.
Given the easterly low level flow, dew points are not forecast to be
as high as previous heat waves this summer. Forecast dew points
through the long term will be from 65 to 70, which is rather low
compared to the 75 to 80 degree dew points earlier this summer. The
ground has become significantly drier since the July flooding
events, which supports a forecast of lower humidity levels. On the
other hand, lower humidity also supports higher temps during the
day.
Will need to keep an eye the the possibility of an easterly wave
moving west into the se U.S. toward the end of the long term. At
minimum, this wave could help to bring down temps a notch or two,
and could also bring a few showers to portions of the region, esp
wrn KY.
&&
.AVIATION...
Issued at 1146 PM CDT MON AUG 31 2015
MVFR fog is expected at all sites after 08z, and brief IFR is
possible mainly at KCGI/KPAH. After 13z, conditions will be VFR
with SCT040 cumulus after 15z. Calm to light south winds overnight
will become south/southwest near 5kts after 13z.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
SHORT TERM...DRS
LONG TERM...GM
AVIATION...RST
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
837 PM EDT WED SEP 2 2015
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 328 PM EDT WED SEP 2 2015
A WEAK COLD FRONT WILL MOVE SOUTH ACROSS LOWER MICHIGAN DURING THE
NEXT 36 HOURS AND CHANCE FOR SHOWERS AND THUNDERSTORMS WILL INCREASE
ACCORDINGLY. TEMPERATURES WILL BE A COUPLE OF DEGREES COOLER
THURSDAY AND FRIDAY DUE TO MORE CLOUDS AND SHOWERS. TEMPERATURES
WILL CLIMB BACK TO THE UPPER 80S BY THE END OF THE WEEKEND HOWEVER.
&&
.UPDATE...
ISSUED AT 836 PM EDT WED SEP 2 2015
AS SUGGESTED BY THE SHORT TERM DISCUSSION THE SHORT WAVE OVER
WISCONSIN WILL BRING ADDITIONAL CONVECTION TO OUR CWA EARLY
THURSDAY MORNING. THERE IS CONSIDERABLE MID LEVEL INSTABILITY TO
WORK WITH TONIGHT SO EVEN THOUGH CONVECTION WILL NOT BE SURFACE
BASED. THE 20 TO 25 KNOT LOW LEVEL JET ON THE SOUTH SIDE OF THE
UPPER LEVEL CIRCULATION REACHES OUR NORTHWEST COAST (MASON/OCEANA
COUNTIES AFTER MIDNIGHT) THEN SLOWLY SLIDES SOUTH WITH THE UPPER
WAVE...NOT MAKING A LOT OF PROGRESS INLAND. I AM THINKING WE WILL
SEE CONVECTION MOVE ONSHORE AFTER MIDNIGHT OVER OUR NORTHERN CWA
THAT WILL SLOWLY SLIDE SOUTH (DEVELOP SOUTH) THROUGH THE EARLY
MORNING HOURS. I DO NOT EXPECT SEVERE STORMS DUE TO THE LACK OF
SIGNIFICANT DEEP LAYER SHEAR BUT WE COULD SEE BRIEF HEAVY
RAINFALL.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 328 PM EDT WED SEP 2 2015
FORECAST CONCERNS DEAL WITH CONVECTIVE POTENTIAL DURING THE PERIOD.
THE SHORT WAVE THAT WAS GENERATING CONVECTION YESTERDAY OVER
NORTHEAST NEBRASKA AND THE EASTERN DAKOTAS HAS MIGRATED TO NORTHEAST
WISCONSIN WHERE IT IS GENERATING SHOWERS/STORMS...SOME OF WHICH HAVE
BEEN SEVERE. THIS WAVE IS PROGD TO MOVE OVER NORTHERN LOWER LATER
TONIGHT AND THURSDAY. CURRENTLY WE`RE SITTING ON 4000 J/KG SBCAPE
BUT NOT MUCH SHEAR. SCATTERED STORMS HAVE DEVELOPED OVER THE FAR
NORTHEAST CWA EARLY THIS AFTERNOON BUT HAVE BEEN WELL BELOW SEVERE
LEVELS. THE STRONGER STORMS OVER WISCONSIN HAVE BEEN IN A MORE
FAVORABLE SHEAR ENVIRONMENT WITH 40KTS NOTED ACROSS NRN WISCONSIN.
SHEAR VALUES ARE PROGD TO REMAIN 15KTS OR LESS THURSDAY ACROSS THE
CWA...SO ANY STORMS THAT DEVELOP LIKELY WON/T BE SEVERE. GIVEN THE
INCREASE IN CLOUD COVER EXPECTED...INSTABILITY WILL PROBABLY BE LESS
THAN TODAY TOO. THAT SAID...MORE FORCING IN THE WAY OF THE WEAK COLD
FRONT AND THE UPPER WAVE SHOULD LEAD TO MORE PCPN COVERAGE. WE/VE
INCREASED POPS TO LIKELY DURING THE AFTERNOON. ANOTHER THING TO
WATCH FOR WILL BE TO SEE IF ANY STORMS DEVELOP ON THE CONVERGENCE OF
THE EASTWARD MOVING LAKE BREEZE AS IT INTERACTS WITH THE NE WINDS
BEHIND THE FRONT. THIS COLD FRONT ISN/T THAT STRONG SO CONVERGENCE
MAY NOT BE SIGNIFICANT.
THE UPPER WAVE WILL BE SLOW TO DEPART SO CHANCES FOR SHOWERS AND
STORMS WILL LINGER INTO FRIDAY...ALTHOUGH CHANCES WILL BE LOWER THAN
ON THURSDAY.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 328 PM EDT WED SEP 2 2015
THE OVERALL SYNOPTIC PATTERN CHANGES LITTLE ON SATURDAY AND SUNDAY
WITH VERY WARM AND HUMID CONDITIONS CONTINUING UNDER THE UPPER
RIDGE. ISOLATED SHOWERS AND STORMS STILL CANT BE RULED OUT
ESPECIALLY DURING PEAK HEATING DUE TO THE COMBINATION OF INSTABILITY
AND POTENTIAL FOR MESOSCALE LOW LEVEL CONVERGENCE ZONES.
THE RIDGE BEGINS TO GRADUALLY BREAK DOWN EARLY NEXT WEEK AND A SFC
COLD FRONT IS PROGGED TO COME THROUGH MONDAY AND MONDAY NIGHT.
HOWEVER THIS FRONT LOOKS WEAK WITH THE GOOD UPPER SUPPORT STILL WELL
OFF TO OUR NORTHWEST. GIVEN CONTINUED WEAK DEEP LAYER SHEAR BELIEVE
THAT THE SVR WEATHER THREAT ON LABOR DAY IS VERY LOW. THE FRONT
SHOULD PROVIDE LESS HUMID CONDITIONS BEHIND IT HOWEVER FOR TUESDAY
AS IT HANGS UP JUST SOUTH AND EAST OF THE STATE.
PERHAPS A BETTER RISK OF ORGANIZED STRONG TO SEVERE STORMS WILL COME
NEXT WEDNESDAY WHEN DEEP LAYER SHEAR RAMPS UP AND MODELS SHOW THE
FRONT LIFTING BACK TO THE NORTH... WITH SOME SUGGESTION OF A WAVE
DEVELOPING/DEEPENING AS IT MOVES NORTHEAST FROM IOWA.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 758 PM EDT WED SEP 2 2015
IT SHOULD BE QUIET AT ALL OF THE TAF SITES EARLY THIS EVENING BUT
EXPECT THUNDERSTORMS IN THE WESTERN TAFS BETWEEN 06Z AND 12Z (OR
SO). AN UPPER LEVEL SHORTWAVE OVER WISCONSIN LATE THIS AFTERNOON
WILL CROSS LAKE MICHIGAN TONIGHT AND LIKELY SET OF A PERIOD OF
SHOWERS AND THUNDERSTORMS (SHOWN BY NSSL WAF...HRRR CR... RAP13...
NAM12) MOVE ACROSS THE WESTERN TAF SITES IN THE 06Z TO 12Z TIME
FRAME. ALL OF THE MODELS SHOW THE STORMS WEAKENING EAST OF US-131
IN THE 12Z TO 15Z TIME FRAME. LAST NIGHT THE STORMS DID NOT WEAKEN
AS THEY MOVED TOWARD LAN DUE TO A WEAK LOW LEVEL JET THAT KEPT
THEM TOGETHER. TONIGHT THE LOW LEVEL JET AGAIN COMES INTO THE
PICTURE. THIS TIME IT IS AROUND THE SYSTEM IN WISCONSIN AND IT
STRENGTHENS OVERNIGHT AS IS TYPICAL(SHOWN BY NAM AND RAP MODEL).
THE JET CORE MOVING SOUTH ALONG THE WEST SHORE OF LAKE MICHIGAN
BETWEEN 09Z AND 16Z. THIS SUPPORTS THE IDEA OF THE CONVECTION NOT
GETTING INLAND TO FAR. SO... THAT IS HOW I PLAYED THE TAFS. I
HAVE...LIKE THE PREVIOUS FORECASTER... HAVE SHOWERS WITH TEMPO
THUNDERSTORMS AT MKG...GRR...AZO...BTL. AS FOR THURSDAY... MORE
AFTERNOON CONVECTION.
&&
.MARINE...
ISSUED AT 328 PM EDT WED SEP 2 2015
OUTSIDE OF A FEW THUNDERSTORMS...MARINE CONDITIONS SHOULD BE QUIET
OVER THE NEXT 24 HRS. A LIGHT OFFSHORE WIND IS LIKELY TO DEVELOP
LATER THURSDAY AS A WEAK COLD FRONT DROPS SOUTH.
&&
.HYDROLOGY...
ISSUED AT 1147 AM EDT WED SEP 2 2015
CONFIDENCE IS INCREASING THAT OUR AREA WILL SEE AT LEAST SCATTERED
THUNDERSTORMS THURSDAY... OR PERHAPS A MORE EXPANSIVE CLUSTER. A
SLOW MOVING THUNDERSTORM OVER THE CITY OF MASON PRODUCED RAINFALL
RATES OF OVER 1 INCH PER HALF HOUR WEDNESDAY MORNING. WHILE BRIEF
HEAVY RAINFALL IS NOT MUCH OF A CONCERN IN MOST LOCATIONS... SOME
STORMS MAY PERSIST LOCALLY AND PRODUCE MORE SIGNIFICANT RAINFALL
TOTALS. THIS MAY CAUSE SOME FLOODING ISSUES IN URBAN AND POOR
DRAINAGE AREAS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...04
SHORT TERM...04
LONG TERM...MEADE
AVIATION...WDM
HYDROLOGY...CAS
MARINE...04
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
757 PM EDT WED SEP 2 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 328 PM EDT WED SEP 2 2015
A WEAK COLD FRONT WILL MOVE SOUTH ACROSS LOWER MICHIGAN DURING THE
NEXT 36 HOURS AND CHANCE FOR SHOWERS AND THUNDERSTORMS WILL INCREASE
ACCORDINGLY. TEMPERATURES WILL BE A COUPLE OF DEGREES COOLER
THURSDAY AND FRIDAY DUE TO MORE CLOUDS AND SHOWERS. TEMPERATURES
WILL CLIMB BACK TO THE UPPER 80S BY THE END OF THE WEEKEND HOWEVER.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 328 PM EDT WED SEP 2 2015
FORECAST CONCERNS DEAL WITH CONVECTIVE POTENTIAL DURING THE PERIOD.
THE SHORT WAVE THAT WAS GENERATING CONVECTION YESTERDAY OVER
NORTHEAST NEBRASKA AND THE EASTERN DAKOTAS HAS MIGRATED TO NORTHEAST
WISCONSIN WHERE IT IS GENERATING SHOWERS/STORMS...SOME OF WHICH HAVE
BEEN SEVERE. THIS WAVE IS PROGD TO MOVE OVER NORTHERN LOWER LATER
TONIGHT AND THURSDAY. CURRENTLY WE`RE SITTING ON 4000 J/KG SBCAPE
BUT NOT MUCH SHEAR. SCATTERED STORMS HAVE DEVELOPED OVER THE FAR
NORTHEAST CWA EARLY THIS AFTERNOON BUT HAVE BEEN WELL BELOW SEVERE
LEVELS. THE STRONGER STORMS OVER WISCONSIN HAVE BEEN IN A MORE
FAVORABLE SHEAR ENVIRONMENT WITH 40KTS NOTED ACROSS NRN WISCONSIN.
SHEAR VALUES ARE PROGD TO REMAIN 15KTS OR LESS THURSDAY ACROSS THE
CWA...SO ANY STORMS THAT DEVELOP LIKELY WON/T BE SEVERE. GIVEN THE
INCREASE IN CLOUD COVER EXPECTED...INSTABILITY WILL PROBABLY BE LESS
THAN TODAY TOO. THAT SAID...MORE FORCING IN THE WAY OF THE WEAK COLD
FRONT AND THE UPPER WAVE SHOULD LEAD TO MORE PCPN COVERAGE. WE/VE
INCREASED POPS TO LIKELY DURING THE AFTERNOON. ANOTHER THING TO
WATCH FOR WILL BE TO SEE IF ANY STORMS DEVELOP ON THE CONVERGENCE OF
THE EASTWARD MOVING LAKE BREEZE AS IT INTERACTS WITH THE NE WINDS
BEHIND THE FRONT. THIS COLD FRONT ISN/T THAT STRONG SO CONVERGENCE
MAY NOT BE SIGNIFICANT.
THE UPPER WAVE WILL BE SLOW TO DEPART SO CHANCES FOR SHOWERS AND
STORMS WILL LINGER INTO FRIDAY...ALTHOUGH CHANCES WILL BE LOWER THAN
ON THURSDAY.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 328 PM EDT WED SEP 2 2015
THE OVERALL SYNOPTIC PATTERN CHANGES LITTLE ON SATURDAY AND SUNDAY
WITH VERY WARM AND HUMID CONDITIONS CONTINUING UNDER THE UPPER
RIDGE. ISOLATED SHOWERS AND STORMS STILL CANT BE RULED OUT
ESPECIALLY DURING PEAK HEATING DUE TO THE COMBINATION OF INSTABILITY
AND POTENTIAL FOR MESOSCALE LOW LEVEL CONVERGENCE ZONES.
THE RIDGE BEGINS TO GRADUALLY BREAK DOWN EARLY NEXT WEEK AND A SFC
COLD FRONT IS PROGGED TO COME THROUGH MONDAY AND MONDAY NIGHT.
HOWEVER THIS FRONT LOOKS WEAK WITH THE GOOD UPPER SUPPORT STILL WELL
OFF TO OUR NORTHWEST. GIVEN CONTINUED WEAK DEEP LAYER SHEAR BELIEVE
THAT THE SVR WEATHER THREAT ON LABOR DAY IS VERY LOW. THE FRONT
SHOULD PROVIDE LESS HUMID CONDITIONS BEHIND IT HOWEVER FOR TUESDAY
AS IT HANGS UP JUST SOUTH AND EAST OF THE STATE.
PERHAPS A BETTER RISK OF ORGANIZED STRONG TO SEVERE STORMS WILL COME
NEXT WEDNESDAY WHEN DEEP LAYER SHEAR RAMPS UP AND MODELS SHOW THE
FRONT LIFTING BACK TO THE NORTH... WITH SOME SUGGESTION OF A WAVE
DEVELOPING/DEEPENING AS IT MOVES NORTHEAST FROM IOWA.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 758 PM EDT WED SEP 2 2015
IT SHOULD BE QUIET AT ALL OF THE TAF SITES EARLY THIS EVENING BUT
EXPECT THUNDERSTORMS IN THE WESTERN TAFS BETWEEN 06Z AND 12Z (OR
SO). AN UPPER LEVEL SHORTWAVE OVER WISCONSIN LATE THIS AFTERNOON
WILL CROSS LAKE MICHIGAN TONIGHT AND LIKELY SET OF A PERIOD OF
SHOWERS AND THUNDERSTORMS (SHOWN BY NSSL WAF...HRRR CR... RAP13...
NAM12) MOVE ACROSS THE WESTERN TAF SITES IN THE 06Z TO 12Z TIME
FRAME. ALL OF THE MODELS SHOW THE STORMS WEAKENING EAST OF US-131
IN THE 12Z TO 15Z TIME FRAME. LAST NIGHT THE STORMS DID NOT WEAKEN
AS THEY MOVED TOWARD LAN DUE TO A WEAK LOW LEVEL JET THAT KEPT
THEM TOGETHER. TONIGHT THE LOW LEVEL JET AGAIN COMES INTO THE
PICTURE. THIS TIME IT IS AROUND THE SYSTEM IN WISCONSIN AND IT
STRENGTHENS OVERNIGHT AS IS TYPICAL(SHOWN BY NAM AND RAP MODEL).
THE JET CORE MOVING SOUTH ALONG THE WEST SHORE OF LAKE MICHIGAN
BETWEEN 09Z AND 16Z. THIS SUPPORTS THE IDEA OF THE CONVECTION NOT
GETTING INLAND TO FAR. SO... THAT IS HOW I PLAYED THE TAFS. I
HAVE...LIKE THE PREVIOUS FORECASTER... HAVE SHOWERS WITH TEMPO
THUNDERSTORMS AT MKG...GRR...AZO...BTL. AS FOR THURSDAY... MORE
AFTERNOON CONVECTION.
&&
.MARINE...
ISSUED AT 328 PM EDT WED SEP 2 2015
OUTSIDE OF A FEW THUNDERSTORMS...MARINE CONDITIONS SHOULD BE QUIET
OVER THE NEXT 24 HRS. A LIGHT OFFSHORE WIND IS LIKELY TO DEVELOP
LATER THURSDAY AS A WEAK COLD FRONT DROPS SOUTH.
&&
.HYDROLOGY...
ISSUED AT 1147 AM EDT WED SEP 2 2015
CONFIDENCE IS INCREASING THAT OUR AREA WILL SEE AT LEAST SCATTERED
THUNDERSTORMS THURSDAY... OR PERHAPS A MORE EXPANSIVE CLUSTER. A
SLOW MOVING THUNDERSTORM OVER THE CITY OF MASON PRODUCED RAINFALL
RATES OF OVER 1 INCH PER HALF HOUR WEDNESDAY MORNING. WHILE BRIEF
HEAVY RAINFALL IS NOT MUCH OF A CONCERN IN MOST LOCATIONS... SOME
STORMS MAY PERSIST LOCALLY AND PRODUCE MORE SIGNIFICANT RAINFALL
TOTALS. THIS MAY CAUSE SOME FLOODING ISSUES IN URBAN AND POOR
DRAINAGE AREAS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...04
SHORT TERM...04
LONG TERM...MEADE
AVIATION...WDM
HYDROLOGY...CAS
MARINE...04
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
439 PM EDT TUE SEP 1 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 438 PM EDT TUE SEP 1 2015
WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW WSW FLOW INTO THE UPPER
GREAT LAKES. SOME DISTURBANCES ARE NOTED IN THE FLOW...ONE IS IN NE
MN AND THE OTHERS ARE IN SE SD/NE NEBRASKA. DESPITE PRESENCE OF
SHORTWAVE NEARBY AND MLCAPES OF 1500-2500J/KG...NO SHRA OR TSTMS
HAVE DEVELOPED YET THIS AFTN. PER VIS SATELLITE IMAGERY...THERE IS
AN AREA OF WHAT LOOKS LIKE ENHANCED CU DEVELOPMENT FROM MENOMINEE
COUNTY TO ERN MARQUETTE COUNTY AND THEN E TO NRN LUCE COUNTY IN
VCNTY OF LAKE BREEZE OFF LAKE MICHIGAN. TO THE W...SCT
-SHRA/SPRINKLES THAT WERE NEAR/JUST OFFSHORE OF WRN UPPER MI THIS
MORNING HAVE MADE LITTLE EASTWARD PROGRESS AND ARE DIMINISHING IN
COVERAGE. IT`S BEEN ANOTHER UNCOMFORTABLY HOT/HUMID DAY. DWPTS RANGE
FROM THE MID 60S TO LWR 70S WITH TEMPS GENERALLY BTWN 80F AND 90F.
COOLEST CONDITIONS (UPPER 60S/LWR 70S) ARE AT LAKESIDE LOCATIONS
ALONG LAKE MICHIGAN E OF KESC.
WITH THE LACK OF CONVECTION SO FAR THIS AFTN...POTENTIAL FOR
SHRA/TSTM DEVELOPMENT DOESN`T LOOK PROMISING. IF SHRA/TSTMS DO
FORM...IT LOOKS LIKE THE BEST POTENTIAL WILL BE IN THE VCNTY OF THE
LAKE MICHIGAN LAKE BREEZE WHERE CU LOOKS BETTER DEVELOPED ATTM.
RECENT HRRR RUNS POINT TOWARD THAT POSSIBILITY. NOTHING MUCH HIGHER
THAN SCHC POPS WILL UTILIZED INTO THE EARLY EVENING HRS. UPSTREAM
SHORTWAVES OVER SD/NEBRASKA WILL DRIFT NE DURING THE NIGHT...AND
PROBABLY SHOULDN`T POSE A RISK FOR PCPN OVERNIGHT. SOME OF THE DRIER
AIR IN NRN MN WHERE DWPTS HAVE DROPPED OFF AS LOW AS THE UPPER 40S
WILL TRY TO MAKE SOME INROADS INTO UPPER MI DURING THE NIGHT...BUT
GIVEN WEAK LOW-LEVEL WIND FIELDS AND AREAS OF FOG OVER LAKE
SUPERIOR...LITTLE OR NONE OF THIS DRIER AIR SHOULD BE REALIZED HERE.
END RESULT...SHOULD BE ANOTHER NIGHT WITH FOG AND STRATUS
DEVELOPMENT IN MANY AREAS.
IT APPEARS THAT WITH UPSTREAM SHORTWAVES MOVING INTO WI/UPPER MI
WED...THERE SHOULD BE A BETTER POTENTIAL OF SHRA/TSTM DEVELOPMENT.
AS OPPOSED TO THE PCPN POTENTIAL TODAY...MODEL CONSENSUS IS MUCH
BETTER FOR SOME PCPN TO OCCUR ON WED...MAINLY OVER THE INTERIOR W
HALF WHERE INSTABILITY WILL BE GREATER. FOR NOW...OPTED TO RAISE
POPS INTO THE LOW/MID RANGE CHC CATEGORY TOWARD THE WI BORDER. IT
WILL BE A LITTLE COOLER WED...ESPECIALLY NEAR LAKE SUPERIOR WHERE
LAKE BREEZE WILL BE MORE ACTIVE THAN TODAY. DWPTS MIGHT BE A LITTLE
LOWER...BUT CONDITIONS WILL STILL BE UNCOMFORTABLY HUMID.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 351 PM EDT TUE SEP 1 2015
AT 00Z THURSDAY A SHORTWAVE WILL BE SET UP ACROSS UPPER MI AND
WI...RIDING THE N EDGE OF THE LARGER 500MB RIDGE SET UP ACROSS MUCH
OF THE CENTRAL U.S.
AS A RESULT...WILL START OFF WITH SLIGHT CHANCE POPS SLOWLY EXITING
SE WEDNESDAY NIGHT...WITH MAINLY DRY WEATHER THEN FIGURED THURSDAY
THROUGH AT LEAST FRIDAY AS THE 500MB RIDGE BUILDS BACK ACROSS THE
UPPER GREAT LAKES. 80S STILL LOOK ON TRACK FOR TEMPS THROUGH
SATURDAY...IF NOT SUNDAY TOO. THERE WILL BE SLIGHT DIFFERENCES EACH
DAY...BUT MAINLY A BETTER PUSH OF AIR OFF LAKE MI WHERE THEY WILL BE
HELD IN THE 70S.
A LOW EJECTING OUT OF THE PACIFIC NW WILL SWING TO THE S CENTRAL
CANADA AND THE DAKOTAS BY 12Z MONDAY...WITH A BREAKDOWN OF THE UPPER
LEVEL RIDGE OVER THE UPPER GREAT LAKES. BEST CHANCE OF RAIN LOOKS TO
BE LATER SUNDAY NIGHT INTO MONDAY. THE LATEST ECMWF SHOWS ONLY
LIMITED PRECIP REMAINING AS THE SYSTEM MOVES E DURING THE DAY
MONDAY. LOOK FOR TEMPERATURES TO FALL BACK TO NEAR NORMAL FOR HIGHS
MONDAY...AND THEN QUITE A CHANGE FOR TUESDAY WITH HIGHS CURRENTLY
ONLY FCST TO BE IN THE MID TO UPPER 60S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 147 PM EDT TUE SEP 1 2015
VFR CONDITIONS WILL PREVAIL INTO THE EVENING HRS AT KIWD/KCMX/KSAW.
A WEAK SURFACE TROUGH MOVING INTO THE AREA COULD SPARK ISOLD SHRA OR
TSTMS THIS AFTN...BUT POTENTIAL OF ANY OF THE TERMINALS BEING
AFFECTED IS TOO LOW TO INCLUDE MENTION IN FCST. IF SHRA DO
DEVELOP...THEY WILL PROBABLY BE MORE LIKELY TO OCCUR IN THE VCNTY OF
KSAW. FOG AND STRATUS WILL LIKELY BE AN ISSUE AGAIN TONIGHT WITH IFR
CONDITIONS POSSIBLE. IMPROVEMENT TO VFR WILL OCCUR AROUND MID
MORNING ON WED.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 438 PM EDT TUE SEP 1 2015
SUMMER PATTERN WILL DOMINATE THE UPPER GREAT LAKES THRU THE WEEK
WITH WINDS ON LAKE SUPERIOR UNDER 20KT. FOR MUCH OF THE TIME...
WINDS WILL BE UNDER 15KT. AT SOME POINT OVER THE WEEKEND...LIKELY
LATE IN THE WEEKEND...PRES GRADIENT WILL TIGHTEN AHEAD OF AN
APPROACHING COLD FRONT. THIS WILL LEAD TO AN UPTICK IN WINDS WITH A
BETTER POTENTIAL FOR GUSTS TO REACH THE 20-30KT RANGE. FINALLY...FOG
MAY BE AN ISSUE OVER AT LEAST PORTIONS OF THE LAKE FOR THE NEXT
SEVERAL DAYS UNDER WARM/HUMID AIR MASS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
DENSE FOG ADVISORY UNTIL 8 AM EDT WEDNESDAY FOR LMZ248-250.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KF
AVIATION...ROLFSON
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
351 PM EDT TUE SEP 1 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 414 AM EDT TUE SEP 1 2015
MUCH OF THE FOCUS ON THE SHORT TERM WILL BE WITH THE WEAK SURFACE
TROUGH DECAYING AS IT MOVES EAST ACROSS THE AREA TODAY AND TONIGHT
AND THE POTENTIAL FOR A FEW SHOWERS/THUNDERSTORMS ALONG IT. WATER
VAPOR IMAGERY AND RAP ANALYSIS SHOW THE UPPER RIDGE AXIS IS SHIFTING
EAST ACROSS LAKE HURON EARLY THIS MORNING...WHICH IS ALLOWING A
PLUME OF MOISTURE STRETCHING FROM NORTHWEST MEXICO TO JAMES BAY TO
SLOWLY MOVE EAST TOWARDS THE AREA. DID SEE A FEW SHOWERS ALONG THE
SURFACE TROUGH AND MOISTURE PLUME EARLIER IN THE NIGHT IN NORTHERN
MINNESOTA BUT THEY HAVE SINCE DISSIPATED. OUT AHEAD OF THE
TROUGH...THE COMBINATION OF VERY RADIATIONAL COOLING AND
SOUTHWESTERLY WINDS PULLING MOIST AIR ACROSS LAKE MICHIGAN HAS
PRODUCED FOG ONCE AGAIN OVER EASTERN UPPER MICHIGAN. THE LOWEST
VISIBILITIES HAVE BEEN RIGHT ALONG THE LAKE MICHIGAN
SHORELINE...WITH VISIBILITIES AT 1/4MI AT TIMES. DID ISSUE A MARINE
DENSE FOG ADVISORY EARLIER IN THE NIGHT BASED OFF THE SATELLITE
COVERAGE OF THE FOG ON LAKE MICHIGAN AND THE VISIBILITY RAPIDLY
FALLING ONCE IT REACHED KISQ. THE REST OF THE AREA HAS SEEN MOSTLY
CLEAR SKIES AND AREAS WHERE THE WINDS HAVE DECOUPLED HAVE SEEN
PATCHY GROUND FOG. EXPECT THAT TO CONTINUE INTO THE FIRST PART OF
THE MORNING HOURS BEFORE LIFTING TO A BRIEF STRATUS DECK AND THEN
DISSIPATING. ON FINAL ITEM TO NOTE FOR THIS MORNING IS THE SCATTERED
BORDERLINE MVFR/VFR CLOUDS IN WESTERN WISCONSIN. THESE HAVE BEEN
SHIFTING TO THE NORTH THIS MORNING AND WILL AID SOME DIURNAL CLOUDS
OVER PORTIONS OF THE AREA TODAY.
PRECIPITATION POTENTIAL IS A LITTLE MORE UP IN THE AIR FOR TODAY AND
LARGELY TIED TO SEVERAL FEATURES COMING TOGETHER IN A NARROW
CORRIDOR THIS AFTERNOON. FIRST...THE MOISTURE PLUME TO THE WEST OF
THE AREA ON WATER VAPOR WILL SHIFT TO THE EAST AND ACROSS THE
WEST/CENTRAL CWA THIS AFTERNOON. WHILE IT LOOKS FAIRLY IMPRESSIVE ON
WV IMAGERY...IT APPEARS THAT THE MODELS ARE DOING FAIRLY WELL ON THE
VERY THIN POCKETS OF MOISTURE WITHIN THAT AREA. SECOND...SOME OF THE
MODELS HAVE HINTS OF A WEAK SHORTWAVE IN EASTERN SOUTH DAKOTA THAT
WILL LIFT TO THE NORTHEAST AND ONLY BRUSH THE WEST/CENTRAL U.P. THIS
AFTERNOON. WHILE MOST OF IT WILL STAY NORTHWEST OF THE LAND
CWA...THERE ARE SOME HINTS AT A SOUTHERN APPENDAGE TO THE SHORTWAVE
THAT MAY WORK WITH THE SURFACE TROUGH AND POCKETS OF MOISTURE AROUND
850MB TO DEVELOP SOME SHOWERS/THUNDERSTORMS THIS AFTERNOON. COARSE
MODELS ARE SHOWING LIMITED DEVELOPMENT...WHILE THE HIGHER RESOLUTION
MODELS (INCLUDING 14KM ECMWF) ARE SHOWING SOME ISOLATED SHOWER
DEVELOPMENT BETWEEN 19-22Z OVER WEST-CENTRAL UPPER MICHIGAN
(GENERALLY FROM KIWD THROUGH BARAGA COUNTY AND INTO NORTHERN
MARQUETTE COUNTY). NCAR WRF ENSEMBLES FOCUS ON THAT AREA TOO FOR
INITIAL DEVELOPMENT BUT THEN EXPAND IT EAST-SOUTHEAST INTO THE
CENTRAL U.P. THIS EVENING (MARQUETTE/ALGER/DELTA AND NRN MENOMINEE).
HAVE KEPT THE POPS CONFINED TO THE AREA IMMEDIATELY AHEAD OF THE
WEAK TROUGH AND OVER THE LAND AREAS OF WEST/CENTRAL UPPER MICHIGAN.
WILL CONTINUE TO SHOW SLIGHT CHANCES BASED OFF THE UNCERTAINTY OF
THE SHORTWAVE BEING CLOSE/STRONG ENOUGH TO HELP THE SHOWERS AND ALSO
THE MARGINAL MOISTURE...ALTHOUGH DID INCLUDE A FEW CHANCES FOR THE
SOUTHERN HOUGHTON AND BARAGA COUNTY AREA DUE TO THE CONSISTENCY IN
THE MODELS ON SOMETHING OCCURRING IN THAT AREA. IN ADDITION...THERE
ARE INDICATIONS OF A VERY NARROW CORRIDOR OF STRONGER 0-6KM BULK
SHEAR (30-35KTS) OVER NORTH CENTRAL UPPER MICHIGAN ALTHOUGH MOST
AREAS WILL BE IN THE 20-25KT RANGE. COMBINING THAT WITH MLCAPE
VALUES OF 1-2K J/KG THIS AFTERNOON...THERE IS THE POTENTIAL FOR A
STRONGER STORM IF ALL OF THE PIECES COME TOGETHER.
THE TROUGH WILL CONTINUE SOUTHEAST AND WEAKEN THROUGH THE NIGHT
TONIGHT...LEADING TO A SUBTLE WIND SHIFT TO THE WEST-NORTHWEST.
SHOWERS SHOULD DISSIPATE THROUGH THE EVENING HOURS OVER THE
NORTHEASTERN PART OF THE CWA AND LEAD TO A PARTLY CLOUDY TO MOSTLY
CLEAR NIGHT. WILL HAVE TO WATCH FOR FOG DEVELOPMENT AGAIN
TONIGHT...ALTHOUGH THE MODELS ARE SHOWING SLIGHTLY DRIER LOW LEVEL
AIR. HAVE INCLUDED PATCHY TO AREAS OF FOG FOR NOW AND A LOT WILL
DEPEND ON THE DRYING BEHIND THE WEAK TROUGH.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 351 PM EDT TUE SEP 1 2015
AT 00Z THURSDAY A SHORTWAVE WILL BE SET UP ACROSS UPPER MI AND
WI...RIDING THE N EDGE OF THE LARGER 500MB RIDGE SET UP ACROSS MUCH
OF THE CENTRAL U.S.
AS A RESULT...WILL START OFF WITH SLIGHT CHANCE POPS SLOWLY EXITING
SE WEDNESDAY NIGHT...WITH MAINLY DRY WEATHER THEN FIGURED THURSDAY
THROUGH AT LEAST FRIDAY AS THE 500MB RIDGE BUILDS BACK ACROSS THE
UPPER GREAT LAKES. 80S STILL LOOK ON TRACK FOR TEMPS THROUGH
SATURDAY...IF NOT SUNDAY TOO. THERE WILL BE SLIGHT DIFFERENCES EACH
DAY...BUT MAINLY A BETTER PUSH OF AIR OFF LAKE MI WHERE THEY WILL BE
HELD IN THE 70S.
A LOW EJECTING OUT OF THE PACIFIC NW WILL SWING TO THE S CENTRAL
CANADA AND THE DAKOTAS BY 12Z MONDAY...WITH A BREAKDOWN OF THE UPPER
LEVEL RIDGE OVER THE UPPER GREAT LAKES. BEST CHANCE OF RAIN LOOKS TO
BE LATER SUNDAY NIGHT INTO MONDAY. THE LATEST ECMWF SHOWS ONLY
LIMITED PRECIP REMAINING AS THE SYSTEM MOVES E DURING THE DAY
MONDAY. LOOK FOR TEMPERATURES TO FALL BACK TO NEAR NORMAL FOR HIGHS
MONDAY...AND THEN QUITE A CHANGE FOR TUESDAY WITH HIGHS CURRENTLY
ONLY FCST TO BE IN THE MID TO UPPER 60S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 147 PM EDT TUE SEP 1 2015
VFR CONDITIONS WILL PREVAIL INTO THE EVENING HRS AT KIWD/KCMX/KSAW.
A WEAK SURFACE TROUGH MOVING INTO THE AREA COULD SPARK ISOLD SHRA OR
TSTMS THIS AFTN...BUT POTENTIAL OF ANY OF THE TERMINALS BEING
AFFECTED IS TOO LOW TO INCLUDE MENTION IN FCST. IF SHRA DO
DEVELOP...THEY WILL PROBABLY BE MORE LIKELY TO OCCUR IN THE VCNTY OF
KSAW. FOG AND STRATUS WILL LIKELY BE AN ISSUE AGAIN TONIGHT WITH IFR
CONDITIONS POSSIBLE. IMPROVEMENT TO VFR WILL OCCUR AROUND MID
MORNING ON WED.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 414 AM EDT TUE SEP 1 2015
SOUTHWESTERLY WINDS WILL WEAKEN THROUGH THE DAY TODAY AS A WEAK
SURFACE TROUGH SLOWLY DROPS SOUTHEAST ACROSS LAKE SUPERIOR TODAY
AND TONIGHT. THIS WILL LEAD TO WINDS FALLING BELOW 15KTS THIS
AFTERNOON AND REMAIN THAT WAY INTO THURSDAY AS A HIGH PRESSURE
RIDGE NOSES BACK NORTHWEST INTO THE UPPER GREAT LAKES REGION.
SOUTHERLY FLOW WILL STRENGTHEN FRIDAY INTO THE WEEKEND AHEAD OF A
BROAD LOW PRESSURE TROUGH STRETCHING FROM CENTRAL CANADA TO THE
CENTRAL PLAINS THAT WILL MOVE EAST INTO THE UPPER MISSISSIPPI
VALLEY. FINALLY...EXPECT PATCHY TO AREAS OF FOG TO OCCUR OVER LAKE
SUPERIOR INTO THURSDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
DENSE FOG ADVISORY UNTIL 8 AM EDT WEDNESDAY FOR LMZ248-250.
&&
$$
SHORT TERM...SRF
LONG TERM...KF
AVIATION...ROLFSON
MARINE...SRF
AREA FORECAST DISCUSSION
NWS GAYLORD MI
330 PM EDT TUE SEP 1 2015
.NEAR TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 331 PM EDT TUE SEP 1 2015
WARM AND VERY HUMID OUT THERE THIS AFTERNOON. DEW POINTS SPIKED
INTO THE LOWER 70S IN MOST LOCALES AT MIDDAY...BUT HAVE MIXING OUT
A TOUCH HERE AT MID-AFTERNOON. TEMPS ARE IN THE 80S...SOME 70S IN
MACKINAC AND SE CHIPPEWA COS. CU FIELD IS UNIMPRESSIVE ACROSS
NORTHERN LOWER/EASTERN UPPER MI. MORE VIGOROUS CU IS SEEN IN
EASTERN WI AND THE WEST HALF OF UPPER MI...WHERE DEW POINTS ARE IN
THE LOW AND EVEN MID 70S IN SPOTS. HOWEVER...SHRA/TSRA ARE NOT YET
EVIDENT...OUTSIDE OF SOME WEAKENING SHRA NEAR THE KEWEENAW. THESE
ARE ASSOCIATED WITH A WEAKENING COLD FRONT/WIND SHIFT BOUNDARY
CROSSING WESTERN/CENTRAL SUPERIOR.
THERE IS SOME POTENTIAL FOR SHRA/TSRA TO INCREASE IN THE VICINITY
OF S CENTRAL SUPERIOR BY EARLY EVENING...AS THE INCOMING BOUNDARY
INTERCEPTS THE INSTABILITY PLUME (MLCAPES TO 2K J/KG) POKING INTO
CENTRAL UPPER MI. HI-RES SHORT TERM MODELS ARE OF MIXED OPINIONS
AS TO WHETHER/HOW THIS WILL PLAY OUT. NAM/NSSL-WRF FAVOR BRINGING
CONVECTION INTO EASTERN UPPER MI THIS EVENING. BUT MOST OF THESE
ARE ALREADY BUBBLING OF DEEP CONVECTION NOW...WHICH IS NOT
HAPPENING. SPC HRRR OFFERS PERHAPS THE MOST REALISTIC SOLUTION...
GENERATING CONVECTION NORTH OF MQT AS THE UNSTABLE PLUME LIFTS
OVER THE SUPERIOR COLD DOME...THEN LARGELY KEEPING IT OVER THE BIG
LAKE AS IT MOVES EAST. WAS GIVING SERIOUS THOUGHT EARLIER TO
BOOSTING POPS...BUT LOOKING AT CURRENT CONDITIONS AND MODEL PROGS
HAVE DECIDED THAT CAN/T FAVOR ANYTHING MORE THAN A 20 POP. WILL
MAINTAIN THAT SLIGHT CHANCE IN WESTERN/CENTRAL CHIP/MACK COUNTIES
THRU THIS EVENING.
OTHERWISE...ANOTHER NIGHT WITH AREAS OF FOG. PERHAPS NOT QUITE AS
MUCH AS THIS MORNING (WHICH WAS LESS THAN THE MORNING
BEFORE)...THANKS TO STRONG MIXING AND RESULTING DECREASE IN DEW
POINTS THIS AFTERNOON. STILL AN UNSEASONABLY WARM/STICKY
NIGHT...WITH MINS IN THE MID 60S TO AROUND 70F.
&&
.SHORT TERM...(WEDNESDAY THROUGH FRIDAY)
ISSUED AT 331 PM EDT TUE SEP 1 2015
WEDNESDAY THROUGH FRIDAY....THE LARGE AREA OF HIGH PRESSURE WHICH
HAS BEEN IN PLACE ACROSS THE ERN ONE THIRD OF THE COUNTRY...WILL
REMAIN ANCHORED OVER THE MID ATLANTIC INTO THE UPCOMING WEEKEND. AT
UPPER LVLS...A STRONG 500MB RIDGE ANCHORED OVER THE GULF STATES AND
OHIO VALLEY...WILL CONTINUE TO NUDGE INTO THE GREAT LAKES THROUGH
THE FORECAST PERIOD. MID LVL TEMPS ASSOCIATED WITH THIS UPPER LVL
PATTERN WILL BE WELL ABOVE NORMAL ACRS THE GREAT LAKES INTO THE
UPCOMING WEEKEND...REMAINING AROUND 16C/17C. THIS OVERALL SFC AND
UPPER LVL PATTERN WILL CONTINUE SUMMER LIKE WEATHER...WITH WELL
ABOVE NORMAL TEMPS ACRS NRN MI THROUGH THE END OF THE WORK WEEK.
WILL CONTINUE AT LEAST A PARTLY SUNNY TREND ACROSS THE REGION AS
MODEL SOUNDINGS AND MSTR PROGS SHOW LIMITED MSTR THROUGH THE
COLUMN...WITH 850/500MB RH AROUND 40/60 PCT THROUGH THE FCST PERIOD.
HOWEVER ENOUGH LOW LVL MSTR WILL BE PRESENT TO CONTINUE MUGGY CONDS
ACRS NRN MI...WITH SFC DEW PTS IN THE MID AND UPPER 60S WHILE MID
LVL DEW PTS REMAIN 12C OR GREATER. WILL CONTINUE WITH MAINLY DRY
CONDITIONS ACROSS NRN MI THOUGH A CHANCE OF PCPN EXIST WEDNESDAY
AFTERNOON AND THURSDAY...THE RESULT OF A WEAK RIPPLE IN THE UPPER
FLOW. 850/500MB QVECTORS SHOW SIGNIFICANT ENOUGH CONVERGENCE WITH
APPROACHING 500MB TROUGH WEDNESDAY AND THURSDAY TO GENERATE PCPN
ACRS NRN MI. MODEL SOUNDINGS SHOWING ENOUGH LOW AND MID LVL MSTR
(SFC DW PTS IN THE UPPER 60S) AND INSTABILITY (LI ARND -4C, MU CAPE
BETWEEN 2000 AND 3000 J/KG, 850/500MB LAPSE RATES INCREASING TO 7
C/KM) TO MENTION THUNDERSTORMS WEDNESDAY NIGHT AND THURSDAY IN THE
FORECAST.
&&
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 331 PM EDT TUE SEP 1 2015
HEAT WILL CONTINUE TO BE THE MAIN STORY GOING INTO LABOR DAY...WITH
WELL ABOVE NORMAL TEMPERATURES ACROSS THE FORECAST AREA. A COLD
FRONT ARRIVING EARLY IN THE WEEK WILL FLATTEN OUT THE H5 RIDGING AND
RETURN TEMPERATURES CLOSER TO...THOUGH STILL SLIGHTLY ABOVE...NORMAL
BY THE END OF THE EXTENDED PERIOD. THERE WILL BE A SMALL CHANCE FOR
SOME SCATTERED THUNDERSTORMS THROUGH THE WEEKEND...BUT AS MENTIONED
BY THE PREVIOUS SHIFT...SUBSIDENCE UNDER THE HIGH PRESSURE COULD
HOLD THOSE OFF. THE BETTER CHANCE FOR SHOWERS WILL BE ASSOCIATED
WITH THE EARLY WEEK COLD FRONT...WHICH IS STILL ALL OVER THE PLACE
AS FAR AS TIMING AND PLACEMENT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 142 PM EDT TUE SEP 1 2015
IFR FOG RETURNS LATE TONIGHT.
HIGH PRESSURE IN THE SE US CONTINUES TO PUSH WARM/MUGGY/HAZY AIR
INTO NORTHERN MI ON SW WINDS. VISIBILITIES WILL DECREASE SHORTLY
AFTER SUNSET. MVFR AND EVENTUALLY IFR VSBYS WILL DEVELOP...WITH
PLN THE MOST LIKELY SITE TO GO LIFR. CONDITIONS WILL GRADUALLY
IMPROVE BY MID/LATE MORNING.
MAINLY SW WINDS THIS AFTERNOON...AND AGAIN BY MIDDAY WEDNESDAY.
LIGHT WINDS TONIGHT.
&&
.MARINE...
ISSUED AT 331 PM EDT TUE SEP 1 2015
SW WINDS WILL CONTINUE...AROUND HIGH PRESSURE TO OUR SE. WINDS
WILL BE ENOUGH TO KEEP THE NORTH END OF LAKE MI A LITTLE
BUMPY...IN THE 2-4 FT RANGE...BUT SHORT OF ADVISORY CRITERIA.
AREAS OF MARINE FOG/STRATUS WILL ALSO CONTINUE...THANKS TO THE
HUMID AIR IN PLACE.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
NEAR TERM...JAZ
SHORT TERM...SWR
LONG TERM...ALM
AVIATION...JAZ
MARINE...JAZ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
147 PM EDT TUE SEP 1 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 414 AM EDT TUE SEP 1 2015
MUCH OF THE FOCUS ON THE SHORT TERM WILL BE WITH THE WEAK SURFACE
TROUGH DECAYING AS IT MOVES EAST ACROSS THE AREA TODAY AND TONIGHT
AND THE POTENTIAL FOR A FEW SHOWERS/THUNDERSTORMS ALONG IT. WATER
VAPOR IMAGERY AND RAP ANALYSIS SHOW THE UPPER RIDGE AXIS IS SHIFTING
EAST ACROSS LAKE HURON EARLY THIS MORNING...WHICH IS ALLOWING A
PLUME OF MOISTURE STRETCHING FROM NORTHWEST MEXICO TO JAMES BAY TO
SLOWLY MOVE EAST TOWARDS THE AREA. DID SEE A FEW SHOWERS ALONG THE
SURFACE TROUGH AND MOISTURE PLUME EARLIER IN THE NIGHT IN NORTHERN
MINNESOTA BUT THEY HAVE SINCE DISSIPATED. OUT AHEAD OF THE
TROUGH...THE COMBINATION OF VERY RADIATIONAL COOLING AND
SOUTHWESTERLY WINDS PULLING MOIST AIR ACROSS LAKE MICHIGAN HAS
PRODUCED FOG ONCE AGAIN OVER EASTERN UPPER MICHIGAN. THE LOWEST
VISIBILITIES HAVE BEEN RIGHT ALONG THE LAKE MICHIGAN
SHORELINE...WITH VISIBILITIES AT 1/4MI AT TIMES. DID ISSUE A MARINE
DENSE FOG ADVISORY EARLIER IN THE NIGHT BASED OFF THE SATELLITE
COVERAGE OF THE FOG ON LAKE MICHIGAN AND THE VISIBILITY RAPIDLY
FALLING ONCE IT REACHED KISQ. THE REST OF THE AREA HAS SEEN MOSTLY
CLEAR SKIES AND AREAS WHERE THE WINDS HAVE DECOUPLED HAVE SEEN
PATCHY GROUND FOG. EXPECT THAT TO CONTINUE INTO THE FIRST PART OF
THE MORNING HOURS BEFORE LIFTING TO A BRIEF STRATUS DECK AND THEN
DISSIPATING. ON FINAL ITEM TO NOTE FOR THIS MORNING IS THE SCATTERED
BORDERLINE MVFR/VFR CLOUDS IN WESTERN WISCONSIN. THESE HAVE BEEN
SHIFTING TO THE NORTH THIS MORNING AND WILL AID SOME DIURNAL CLOUDS
OVER PORTIONS OF THE AREA TODAY.
PRECIPITATION POTENTIAL IS A LITTLE MORE UP IN THE AIR FOR TODAY AND
LARGELY TIED TO SEVERAL FEATURES COMING TOGETHER IN A NARROW
CORRIDOR THIS AFTERNOON. FIRST...THE MOISTURE PLUME TO THE WEST OF
THE AREA ON WATER VAPOR WILL SHIFT TO THE EAST AND ACROSS THE
WEST/CENTRAL CWA THIS AFTERNOON. WHILE IT LOOKS FAIRLY IMPRESSIVE ON
WV IMAGERY...IT APPEARS THAT THE MODELS ARE DOING FAIRLY WELL ON THE
VERY THIN POCKETS OF MOISTURE WITHIN THAT AREA. SECOND...SOME OF THE
MODELS HAVE HINTS OF A WEAK SHORTWAVE IN EASTERN SOUTH DAKOTA THAT
WILL LIFT TO THE NORTHEAST AND ONLY BRUSH THE WEST/CENTRAL U.P. THIS
AFTERNOON. WHILE MOST OF IT WILL STAY NORTHWEST OF THE LAND
CWA...THERE ARE SOME HINTS AT A SOUTHERN APPENDAGE TO THE SHORTWAVE
THAT MAY WORK WITH THE SURFACE TROUGH AND POCKETS OF MOISTURE AROUND
850MB TO DEVELOP SOME SHOWERS/THUNDERSTORMS THIS AFTERNOON. COARSE
MODELS ARE SHOWING LIMITED DEVELOPMENT...WHILE THE HIGHER RESOLUTION
MODELS (INCLUDING 14KM ECMWF) ARE SHOWING SOME ISOLATED SHOWER
DEVELOPMENT BETWEEN 19-22Z OVER WEST-CENTRAL UPPER MICHIGAN
(GENERALLY FROM KIWD THROUGH BARAGA COUNTY AND INTO NORTHERN
MARQUETTE COUNTY). NCAR WRF ENSEMBLES FOCUS ON THAT AREA TOO FOR
INITIAL DEVELOPMENT BUT THEN EXPAND IT EAST-SOUTHEAST INTO THE
CENTRAL U.P. THIS EVENING (MARQUETTE/ALGER/DELTA AND NRN MENOMINEE).
HAVE KEPT THE POPS CONFINED TO THE AREA IMMEDIATELY AHEAD OF THE
WEAK TROUGH AND OVER THE LAND AREAS OF WEST/CENTRAL UPPER MICHIGAN.
WILL CONTINUE TO SHOW SLIGHT CHANCES BASED OFF THE UNCERTAINTY OF
THE SHORTWAVE BEING CLOSE/STRONG ENOUGH TO HELP THE SHOWERS AND ALSO
THE MARGINAL MOISTURE...ALTHOUGH DID INCLUDE A FEW CHANCES FOR THE
SOUTHERN HOUGHTON AND BARAGA COUNTY AREA DUE TO THE CONSISTENCY IN
THE MODELS ON SOMETHING OCCURRING IN THAT AREA. IN ADDITION...THERE
ARE INDICATIONS OF A VERY NARROW CORRIDOR OF STRONGER 0-6KM BULK
SHEAR (30-35KTS) OVER NORTH CENTRAL UPPER MICHIGAN ALTHOUGH MOST
AREAS WILL BE IN THE 20-25KT RANGE. COMBINING THAT WITH MLCAPE
VALUES OF 1-2K J/KG THIS AFTERNOON...THERE IS THE POTENTIAL FOR A
STRONGER STORM IF ALL OF THE PIECES COME TOGETHER.
THE TROUGH WILL CONTINUE SOUTHEAST AND WEAKEN THROUGH THE NIGHT
TONIGHT...LEADING TO A SUBTLE WIND SHIFT TO THE WEST-NORTHWEST.
SHOWERS SHOULD DISSIPATE THROUGH THE EVENING HOURS OVER THE
NORTHEASTERN PART OF THE CWA AND LEAD TO A PARTLY CLOUDY TO MOSTLY
CLEAR NIGHT. WILL HAVE TO WATCH FOR FOG DEVELOPMENT AGAIN
TONIGHT...ALTHOUGH THE MODELS ARE SHOWING SLIGHTLY DRIER LOW LEVEL
AIR. HAVE INCLUDED PATCHY TO AREAS OF FOG FOR NOW AND A LOT WILL
DEPEND ON THE DRYING BEHIND THE WEAK TROUGH.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 519 AM EDT TUE SEP 1 2015
UPPER LEVEL RIDGE TO START ON WEDNESDAY FM SOUTHWEST CONUS TO THE
NORTHEAST CONUS ALLOWS FOR POSSIBLE AFTN/EVENING SHRA/TSRA WED AND
THU. EXPECT THE RIDGE TO BUILD BACK FM SOUTHERN PLAINS TO THE UPPER
GREAT LAKES/NORTHERN ONTARIO BY LATE THIS WEEK IN RESPONSE TO STRONG
UPPER TROUGH DIGGING FM WESTERN CANADA DOWN THE WESTERN CONUS COAST.
TROUGH WILL CONTINUE DIGGING SOUTH...POSSIBLY AS FAR AS CALIFORNIA
BY THIS WEEKEND WHILE RIDGE EXPANDS OVER REST OF GREAT LAKES AND
NORTHEAST CONUS. AT THE SFC...SLOW MOVING COLD FRONT WILL BE STUCK
OVER THE PLAINS IN BETWEEN THE UPPER TROUGH AND UPPER RIDGE. SINCE
UPPER PATTERN CHANGES LITTLE THIS WEEKEND AND FRONT WILL BE PARALLEL
TO FLOW ALOFT...FRONT WILL STRUGGLE EASTWARD SATURDAY INTO SUNDAY.
SHORTWAVE CURRENTLY OVER CO/NEB/KS INTERSECTION IS FORECAST TO LIFT
NORTHEAST TO UPPER MISSISSIPPI RIVER VALLEY BY 12Z WED AND THEN TO
MOVE OVER WI/UPR MICHIGAN WED AFTN INTO WED NIGHT. MLCAPES FOCUSED
MORE FM DAKOTAS/NORTHERN MN ESE ACROSS WI AND LOWER MICHIGAN. MEAN
LAYER WINDS WNW-W...SO PREFER THE ECMWF/NAM/GEM-REGIONAL SHOWING
MAJORITY OF QPF OVER NORTHERN WI WITH THE SHRA/TSRA. ALSO NORTHERLY
GRADIENT/LAKE BREEZE ENHANCED WINDS OFF LK SUPERIOR WILL STABILIZE
LOW-LEVELS CLOSER TO LK SUPERIOR AND OVER EASTERN CWA. CHANCE POPS
HIGHEST TOWARD WI BORDER. FOR TEMPS...STUCK TOWARD PREVIOUS FORECAST
WITH MID 80S INLAND WEST HALF. COOLER MID-UPR 70S NEAR LK SUPERIOR
WITH ONSHORE WINDS. IF THOSE ONSHORE WINDS START UP QUICKER...COULD
SEE READINGS ENDING UP COOLER THAN FORECAST CURRENTLY SHOWS. KEPT
LINGERING POPS MAINLY SCNTRL ON WED NIGHT AS THE SHORTWAVE DRIFTS
ACROSS AND SINCE SCNTRL WILL BE ON NORTHERN EDGE OF H85 CONVERGENCE
ZONE AND IN A POTENTIAL MID-LEVEL FGEN AREA WITH THE SHORTWAVE.
SUBSIDENCE INCREASES IN WAKE OF SHORTWAVE LATER THURSDAY INTO
FRIDAY...SO FOR MOST PART THINK IT WILL BE MAINLY DRY COUPLE DAYS.
WINDS TURN BACK TO SSE-S WHICH RESULTS IN BETTER CHANCE OF WARMING
FOR ALL AREAS AWAY FM LK MICHIGAN. H85 TEMPS BUMP UP A COUPLE
DEGREES AS WELL BY SO AFTER LOW-MID 80S ON THU...SHOULD SEE AT LEAST
UPR 80S FOR WEST CWA ON FRIDAY AFTN. LOW-MID 80S ELSEWHERE...EXPECT
UPR 70S NEAR LK MICHIGAN. NO CHANGE AT ALL THE HUMID CONDITIONS THAT
REALLY START UP TODAY...WITH DWPNTS SOLIDLY IN THE 60S. THOUGH NOT
IN THE FORECAST THE ENTIRE TIME...CANNOT RULE OUT FOG JUST ABOUT
ANYTIME WEDNESDAY THROUGH FRIDAY ESPECIALLY NEAR THE GREAT LAKES
SHORES WHERE THERE IS SOME ONSHORE WIND COMPONENT. HAVE SEEN THIS
LAST FEW DAYS AND NO REASON TO BELIEVE IT WILL NOT CONTINUE IN AT
LEAST SOME SHAPE OR FORM.
INTO THIS WEEKEND. EVENTUALLY...STRONGER SHORTWAVE TROUGH FORECAST
TO MOVE INTO WESTERN CANADA WILL ACT AS KICKER TO THE TROUGH OVER
THE NORTHWEST CONUS AND PUSH THE COLD FRONT TO THE EAST WHILE
DEVELOPING A SFC LOW ON ITS NORTHERN EDGE AT THE FOREFRONT OF THE
INITIAL UPPER LEVEL TROUGH. ENTIRE SYSTEM MOVES ACROSS UPPER GREAT
LAKES SUNDAY INTO MONDAY. ECMWF IN 3 OF ITS RUNS OVER LAST FEW DAYS
HAS HINTED THAT SHRA/TSRA MAY BREAK OUT WELL AHEAD OF MAIN FRONT
DOWNSTREAM OF SURGE OF 2000 J/KG MUCAPE FM NORTHERN PLAINS TO
NORTHWEST ONTARIO EITHER SATURDAY OR SUNDAY. 850-300MB THICKNESS
LINES WOULD SUPPORT THAT POTENTIAL SHOWING NW-SE FLOW SATURDAY AND W-
E FLOW ON SUNDAY. LATEST ECMWF NOW BUILDS UPPER RIDGE MORE AND HAS
H85 THETA-E RIDGE AS FAR NORTH AS SOUTHERN MANITOBA AND NORTHWEST
ONTARIO FRIDAY NIGHT INTO SATURDAY. IF THIS OCCURRS IT WOULD LIKELY
STAY DRY OVER UPR MICHIGAN FRIDAY NIGHT INTO SATURDAY AS SHORTWAVES
AND ASSOCIATED SHRA/TSRA WOULD STAY WELL TO THE NORTHWEST OF UPR
MICHIGAN/LK SUPERIOR. THEN...ONCE THE SHORTWAVE TROUGH OVER THE
NORTHWEST CONUS MOVES EASTWARD...THERE WOULD BE INCREASING CHANCES
OF SHRA/TSRA AS THE WEEKEND CONCLUDES AND ON INTO LABOR DAY. KEPT
POPS AT SLIGHT CHANCE OVER SOUTH AND EAST FRIDAY NIGHT INTO SATURDAY
NIGHT WITH CHANCE POPS OVER FAR NW CWA. BY SUNDAY...BROUGHT CHANCE
POPS OVER MORE OF THE NORTH CWA BUT STILL KEPT POPS SLIGHT CHANCE AT
BEST OVER SCNTRL FARTHER AWAY FM THE THETA-E RIDGE AND MORE INTO THE
LARGER SCALE RIDGE.
GFS BLOWS COLD FRONT THROUGH QUICKLY SUNDAY NIGHT INTO MONDAY WHILE
ECMWF IS SLOWER MAINLY DUE TO SHOWING MORE OF A CUTOFF UPPER LOW
OVER THE WESTERN CONUS SATURDAY NIGHT INTO SUNDAY. WILL CONTINUE TO
USE CONSENSUS POPS FOR FORECAST WHICH ARE HIGHEST FOR SUN NIGHT INTO
LABOR DAY. STILL LOOKS COOLER FOR SUNDAY AND LABOR DAY...AT LEAST
COMPARED TO WARMTH THIS WEEK. BASED ON TRENDS FM LATEST MODELS...
CONFIDENCE IS LESSENING IN A SIGNIFICANT COOL DOWN NEXT WEEK. STAY
TUNED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 147 PM EDT TUE SEP 1 2015
VFR CONDITIONS WILL PREVAIL INTO THE EVENING HRS AT KIWD/KCMX/KSAW.
A WEAK SURFACE TROUGH MOVING INTO THE AREA COULD SPARK ISOLD SHRA OR
TSTMS THIS AFTN...BUT POTENTIAL OF ANY OF THE TERMINALS BEING
AFFECTED IS TOO LOW TO INCLUDE MENTION IN FCST. IF SHRA DO
DEVELOP...THEY WILL PROBABLY BE MORE LIKELY TO OCCUR IN THE VCNTY OF
KSAW. FOG AND STRATUS WILL LIKELY BE AN ISSUE AGAIN TONIGHT WITH IFR
CONDITIONS POSSIBLE. IMPROVEMENT TO VFR WILL OCCUR AROUND MID
MORNING ON WED.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 414 AM EDT TUE SEP 1 2015
SOUTHWESTERLY WINDS WILL WEAKEN THROUGH THE DAY TODAY AS A WEAK
SURFACE TROUGH SLOWLY DROPS SOUTHEAST ACROSS LAKE SUPERIOR TODAY
AND TONIGHT. THIS WILL LEAD TO WINDS FALLING BELOW 15KTS THIS
AFTERNOON AND REMAIN THAT WAY INTO THURSDAY AS A HIGH PRESSURE
RIDGE NOSES BACK NORTHWEST INTO THE UPPER GREAT LAKES REGION.
SOUTHERLY FLOW WILL STRENGTHEN FRIDAY INTO THE WEEKEND AHEAD OF A
BROAD LOW PRESSURE TROUGH STRETCHING FROM CENTRAL CANADA TO THE
CENTRAL PLAINS THAT WILL MOVE EAST INTO THE UPPER MISSISSIPPI
VALLEY. FINALLY...EXPECT PATCHY TO AREAS OF FOG TO OCCUR OVER LAKE
SUPERIOR INTO THURSDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
DENSE FOG ADVISORY UNTIL 8 AM EDT WEDNESDAY FOR LMZ248-250.
&&
$$
SHORT TERM...SRF
LONG TERM...JLA
AVIATION...ROLFSON
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
739 AM EDT TUE SEP 1 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 414 AM EDT TUE SEP 1 2015
MUCH OF THE FOCUS ON THE SHORT TERM WILL BE WITH THE WEAK SURFACE
TROUGH DECAYING AS IT MOVES EAST ACROSS THE AREA TODAY AND TONIGHT
AND THE POTENTIAL FOR A FEW SHOWERS/THUNDERSTORMS ALONG IT. WATER
VAPOR IMAGERY AND RAP ANALYSIS SHOW THE UPPER RIDGE AXIS IS SHIFTING
EAST ACROSS LAKE HURON EARLY THIS MORNING...WHICH IS ALLOWING A
PLUME OF MOISTURE STRETCHING FROM NORTHWEST MEXICO TO JAMES BAY TO
SLOWLY MOVE EAST TOWARDS THE AREA. DID SEE A FEW SHOWERS ALONG THE
SURFACE TROUGH AND MOISTURE PLUME EARLIER IN THE NIGHT IN NORTHERN
MINNESOTA BUT THEY HAVE SINCE DISSIPATED. OUT AHEAD OF THE
TROUGH...THE COMBINATION OF VERY RADIATIONAL COOLING AND
SOUTHWESTERLY WINDS PULLING MOIST AIR ACROSS LAKE MICHIGAN HAS
PRODUCED FOG ONCE AGAIN OVER EASTERN UPPER MICHIGAN. THE LOWEST
VISIBILITIES HAVE BEEN RIGHT ALONG THE LAKE MICHIGAN
SHORELINE...WITH VISIBILITIES AT 1/4MI AT TIMES. DID ISSUE A MARINE
DENSE FOG ADVISORY EARLIER IN THE NIGHT BASED OFF THE SATELLITE
COVERAGE OF THE FOG ON LAKE MICHIGAN AND THE VISIBILITY RAPIDLY
FALLING ONCE IT REACHED KISQ. THE REST OF THE AREA HAS SEEN MOSTLY
CLEAR SKIES AND AREAS WHERE THE WINDS HAVE DECOUPLED HAVE SEEN
PATCHY GROUND FOG. EXPECT THAT TO CONTINUE INTO THE FIRST PART OF
THE MORNING HOURS BEFORE LIFTING TO A BRIEF STRATUS DECK AND THEN
DISSIPATING. ON FINAL ITEM TO NOTE FOR THIS MORNING IS THE SCATTERED
BORDERLINE MVFR/VFR CLOUDS IN WESTERN WISCONSIN. THESE HAVE BEEN
SHIFTING TO THE NORTH THIS MORNING AND WILL AID SOME DIURNAL CLOUDS
OVER PORTIONS OF THE AREA TODAY.
PRECIPITATION POTENTIAL IS A LITTLE MORE UP IN THE AIR FOR TODAY AND
LARGELY TIED TO SEVERAL FEATURES COMING TOGETHER IN A NARROW
CORRIDOR THIS AFTERNOON. FIRST...THE MOISTURE PLUME TO THE WEST OF
THE AREA ON WATER VAPOR WILL SHIFT TO THE EAST AND ACROSS THE
WEST/CENTRAL CWA THIS AFTERNOON. WHILE IT LOOKS FAIRLY IMPRESSIVE ON
WV IMAGERY...IT APPEARS THAT THE MODELS ARE DOING FAIRLY WELL ON THE
VERY THIN POCKETS OF MOISTURE WITHIN THAT AREA. SECOND...SOME OF THE
MODELS HAVE HINTS OF A WEAK SHORTWAVE IN EASTERN SOUTH DAKOTA THAT
WILL LIFT TO THE NORTHEAST AND ONLY BRUSH THE WEST/CENTRAL U.P. THIS
AFTERNOON. WHILE MOST OF IT WILL STAY NORTHWEST OF THE LAND
CWA...THERE ARE SOME HINTS AT A SOUTHERN APPENDAGE TO THE SHORTWAVE
THAT MAY WORK WITH THE SURFACE TROUGH AND POCKETS OF MOISTURE AROUND
850MB TO DEVELOP SOME SHOWERS/THUNDERSTORMS THIS AFTERNOON. COARSE
MODELS ARE SHOWING LIMITED DEVELOPMENT...WHILE THE HIGHER RESOLUTION
MODELS (INCLUDING 14KM ECMWF) ARE SHOWING SOME ISOLATED SHOWER
DEVELOPMENT BETWEEN 19-22Z OVER WEST-CENTRAL UPPER MICHIGAN
(GENERALLY FROM KIWD THROUGH BARAGA COUNTY AND INTO NORTHERN
MARQUETTE COUNTY). NCAR WRF ENSEMBLES FOCUS ON THAT AREA TOO FOR
INITIAL DEVELOPMENT BUT THEN EXPAND IT EAST-SOUTHEAST INTO THE
CENTRAL U.P. THIS EVENING (MARQUETTE/ALGER/DELTA AND NRN MENOMINEE).
HAVE KEPT THE POPS CONFINED TO THE AREA IMMEDIATELY AHEAD OF THE
WEAK TROUGH AND OVER THE LAND AREAS OF WEST/CENTRAL UPPER MICHIGAN.
WILL CONTINUE TO SHOW SLIGHT CHANCES BASED OFF THE UNCERTAINTY OF
THE SHORTWAVE BEING CLOSE/STRONG ENOUGH TO HELP THE SHOWERS AND ALSO
THE MARGINAL MOISTURE...ALTHOUGH DID INCLUDE A FEW CHANCES FOR THE
SOUTHERN HOUGHTON AND BARAGA COUNTY AREA DUE TO THE CONSISTENCY IN
THE MODELS ON SOMETHING OCCURRING IN THAT AREA. IN ADDITION...THERE
ARE INDICATIONS OF A VERY NARROW CORRIDOR OF STRONGER 0-6KM BULK
SHEAR (30-35KTS) OVER NORTH CENTRAL UPPER MICHIGAN ALTHOUGH MOST
AREAS WILL BE IN THE 20-25KT RANGE. COMBINING THAT WITH MLCAPE
VALUES OF 1-2K J/KG THIS AFTERNOON...THERE IS THE POTENTIAL FOR A
STRONGER STORM IF ALL OF THE PIECES COME TOGETHER.
THE TROUGH WILL CONTINUE SOUTHEAST AND WEAKEN THROUGH THE NIGHT
TONIGHT...LEADING TO A SUBTLE WIND SHIFT TO THE WEST-NORTHWEST.
SHOWERS SHOULD DISSIPATE THROUGH THE EVENING HOURS OVER THE
NORTHEASTERN PART OF THE CWA AND LEAD TO A PARTLY CLOUDY TO MOSTLY
CLEAR NIGHT. WILL HAVE TO WATCH FOR FOG DEVELOPMENT AGAIN
TONIGHT...ALTHOUGH THE MODELS ARE SHOWING SLIGHTLY DRIER LOW LEVEL
AIR. HAVE INCLUDED PATCHY TO AREAS OF FOG FOR NOW AND A LOT WILL
DEPEND ON THE DRYING BEHIND THE WEAK TROUGH.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 519 AM EDT TUE SEP 1 2015
UPPER LEVEL RIDGE TO START ON WEDNESDAY FM SOUTHWEST CONUS TO THE
NORTHEAST CONUS ALLOWS FOR POSSIBLE AFTN/EVENING SHRA/TSRA WED AND
THU. EXPECT THE RIDGE TO BUILD BACK FM SOUTHERN PLAINS TO THE UPPER
GREAT LAKES/NORTHERN ONTARIO BY LATE THIS WEEK IN RESPONSE TO STRONG
UPPER TROUGH DIGGING FM WESTERN CANADA DOWN THE WESTERN CONUS COAST.
TROUGH WILL CONTINUE DIGGING SOUTH...POSSIBLY AS FAR AS CALIFORNIA
BY THIS WEEKEND WHILE RIDGE EXPANDS OVER REST OF GREAT LAKES AND
NORTHEAST CONUS. AT THE SFC...SLOW MOVING COLD FRONT WILL BE STUCK
OVER THE PLAINS IN BETWEEN THE UPPER TROUGH AND UPPER RIDGE. SINCE
UPPER PATTERN CHANGES LITTLE THIS WEEKEND AND FRONT WILL BE PARALLEL
TO FLOW ALOFT...FRONT WILL STRUGGLE EASTWARD SATURDAY INTO SUNDAY.
SHORTWAVE CURRENTLY OVER CO/NEB/KS INTERSECTION IS FORECAST TO LIFT
NORTHEAST TO UPPER MISSISSIPPI RIVER VALLEY BY 12Z WED AND THEN TO
MOVE OVER WI/UPR MICHIGAN WED AFTN INTO WED NIGHT. MLCAPES FOCUSED
MORE FM DAKOTAS/NORTHERN MN ESE ACROSS WI AND LOWER MICHIGAN. MEAN
LAYER WINDS WNW-W...SO PREFER THE ECMWF/NAM/GEM-REGIONAL SHOWING
MAJORITY OF QPF OVER NORTHERN WI WITH THE SHRA/TSRA. ALSO NORTHERLY
GRADIENT/LAKE BREEZE ENHANCED WINDS OFF LK SUPERIOR WILL STABILIZE
LOW-LEVELS CLOSER TO LK SUPERIOR AND OVER EASTERN CWA. CHANCE POPS
HIGHEST TOWARD WI BORDER. FOR TEMPS...STUCK TOWARD PREVIOUS FORECAST
WITH MID 80S INLAND WEST HALF. COOLER MID-UPR 70S NEAR LK SUPERIOR
WITH ONSHORE WINDS. IF THOSE ONSHORE WINDS START UP QUICKER...COULD
SEE READINGS ENDING UP COOLER THAN FORECAST CURRENTLY SHOWS. KEPT
LINGERING POPS MAINLY SCNTRL ON WED NIGHT AS THE SHORTWAVE DRIFTS
ACROSS AND SINCE SCNTRL WILL BE ON NORTHERN EDGE OF H85 CONVERGENCE
ZONE AND IN A POTENTIAL MID-LEVEL FGEN AREA WITH THE SHORTWAVE.
SUBSIDENCE INCREASES IN WAKE OF SHORTWAVE LATER THURSDAY INTO
FRIDAY...SO FOR MOST PART THINK IT WILL BE MAINLY DRY COUPLE DAYS.
WINDS TURN BACK TO SSE-S WHICH RESULTS IN BETTER CHANCE OF WARMING
FOR ALL AREAS AWAY FM LK MICHIGAN. H85 TEMPS BUMP UP A COUPLE
DEGREES AS WELL BY SO AFTER LOW-MID 80S ON THU...SHOULD SEE AT LEAST
UPR 80S FOR WEST CWA ON FRIDAY AFTN. LOW-MID 80S ELSEWHERE...EXPECT
UPR 70S NEAR LK MICHIGAN. NO CHANGE AT ALL THE HUMID CONDITIONS THAT
REALLY START UP TODAY...WITH DWPNTS SOLIDLY IN THE 60S. THOUGH NOT
IN THE FORECAST THE ENTIRE TIME...CANNOT RULE OUT FOG JUST ABOUT
ANYTIME WEDNESDAY THROUGH FRIDAY ESPECIALLY NEAR THE GREAT LAKES
SHORES WHERE THERE IS SOME ONSHORE WIND COMPONENT. HAVE SEEN THIS
LAST FEW DAYS AND NO REASON TO BELIEVE IT WILL NOT CONTINUE IN AT
LEAST SOME SHAPE OR FORM.
INTO THIS WEEKEND. EVENTUALLY...STRONGER SHORTWAVE TROUGH FORECAST
TO MOVE INTO WESTERN CANADA WILL ACT AS KICKER TO THE TROUGH OVER
THE NORTHWEST CONUS AND PUSH THE COLD FRONT TO THE EAST WHILE
DEVELOPING A SFC LOW ON ITS NORTHERN EDGE AT THE FOREFRONT OF THE
INITIAL UPPER LEVEL TROUGH. ENTIRE SYSTEM MOVES ACROSS UPPER GREAT
LAKES SUNDAY INTO MONDAY. ECMWF IN 3 OF ITS RUNS OVER LAST FEW DAYS
HAS HINTED THAT SHRA/TSRA MAY BREAK OUT WELL AHEAD OF MAIN FRONT
DOWNSTREAM OF SURGE OF 2000 J/KG MUCAPE FM NORTHERN PLAINS TO
NORTHWEST ONTARIO EITHER SATURDAY OR SUNDAY. 850-300MB THICKNESS
LINES WOULD SUPPORT THAT POTENTIAL SHOWING NW-SE FLOW SATURDAY AND W-
E FLOW ON SUNDAY. LATEST ECMWF NOW BUILDS UPPER RIDGE MORE AND HAS
H85 THETA-E RIDGE AS FAR NORTH AS SOUTHERN MANITOBA AND NORTHWEST
ONTARIO FRIDAY NIGHT INTO SATURDAY. IF THIS OCCURRS IT WOULD LIKELY
STAY DRY OVER UPR MICHIGAN FRIDAY NIGHT INTO SATURDAY AS SHORTWAVES
AND ASSOCIATED SHRA/TSRA WOULD STAY WELL TO THE NORTHWEST OF UPR
MICHIGAN/LK SUPERIOR. THEN...ONCE THE SHORTWAVE TROUGH OVER THE
NORTHWEST CONUS MOVES EASTWARD...THERE WOULD BE INCREASING CHANCES
OF SHRA/TSRA AS THE WEEKEND CONCLUDES AND ON INTO LABOR DAY. KEPT
POPS AT SLIGHT CHANCE OVER SOUTH AND EAST FRIDAY NIGHT INTO SATURDAY
NIGHT WITH CHANCE POPS OVER FAR NW CWA. BY SUNDAY...BROUGHT CHANCE
POPS OVER MORE OF THE NORTH CWA BUT STILL KEPT POPS SLIGHT CHANCE AT
BEST OVER SCNTRL FARTHER AWAY FM THE THETA-E RIDGE AND MORE INTO THE
LARGER SCALE RIDGE.
GFS BLOWS COLD FRONT THROUGH QUICKLY SUNDAY NIGHT INTO MONDAY WHILE
ECMWF IS SLOWER MAINLY DUE TO SHOWING MORE OF A CUTOFF UPPER LOW
OVER THE WESTERN CONUS SATURDAY NIGHT INTO SUNDAY. WILL CONTINUE TO
USE CONSENSUS POPS FOR FORECAST WHICH ARE HIGHEST FOR SUN NIGHT INTO
LABOR DAY. STILL LOOKS COOLER FOR SUNDAY AND LABOR DAY...AT LEAST
COMPARED TO WARMTH THIS WEEK. BASED ON TRENDS FM LATEST MODELS...
CONFIDENCE IS LESSENING IN A SIGNIFICANT COOL DOWN NEXT WEEK. STAY
TUNED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 739 AM EDT TUE SEP 1 2015
FOG WILL BE THE PRIMARY CONCERN FOR THE TAF PERIOD...BOTH AT THE
BEGINNING OF THE PERIOD AND OVERNIGHT TONIGHT. HAVE STARTED BOTH
KCMX/KSAW OUT AT VLIFR AND EXPECT TO QUICKLY DIMINISH OVER THE NEXT
COUPLE OF HOURS. THEN A WEAK SURFACE TROUGH WILL MOVES ACROSS THE
AREA THROUGH THE DAY TODAY AND COULD LEAD TO A FEW SHOWERS. HAVE
JUST ADDRESSED THE SHOWERS WITH VCSH AT KIWD/KCMX FOR THIS MORNING
BASED OFF THE RETURNS SEEN ON KDLH RADAR. AS DAYTIME HEATING IS
MAXIMIZED...COULD SEE ADDITIONAL SHOWERS AND MAYBE A FEW
THUNDERSTORMS DEVELOP BUT MOST WILL BE BETWEEN THE THREE TAF SITES.
IF THEY AFFECTED A SITE...THINK KIWD OR KSAW WOULD BE THE MOST
LIKELY. FINALLY...ALTHOUGH THERE WILL BE SOME DRYING OF THE LOWER
LEVELS...THINK GROUND FOG WILL DEVELOP AGAIN TONIGHT AND HAVE PUT
IN VISIBILITIES FALLING TO MVFR VALUES FOR NOW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 414 AM EDT TUE SEP 1 2015
SOUTHWESTERLY WINDS WILL WEAKEN THROUGH THE DAY TODAY AS A WEAK
SURFACE TROUGH SLOWLY DROPS SOUTHEAST ACROSS LAKE SUPERIOR TODAY
AND TONIGHT. THIS WILL LEAD TO WINDS FALLING BELOW 15KTS THIS
AFTERNOON AND REMAIN THAT WAY INTO THURSDAY AS A HIGH PRESSURE
RIDGE NOSES BACK NORTHWEST INTO THE UPPER GREAT LAKES REGION.
SOUTHERLY FLOW WILL STRENGTHEN FRIDAY INTO THE WEEKEND AHEAD OF A
BROAD LOW PRESSURE TROUGH STRETCHING FROM CENTRAL CANADA TO THE
CENTRAL PLAINS THAT WILL MOVE EAST INTO THE UPPER MISSISSIPPI
VALLEY. FINALLY...EXPECT PATCHY TO AREAS OF FOG TO OCCUR OVER LAKE
SUPERIOR INTO THURSDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
DENSE FOG ADVISORY UNTIL NOON EDT TODAY FOR LMZ248-250.
&&
$$
SHORT TERM...SRF
LONG TERM...JLA
AVIATION...SRF
MARINE...SRF
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
519 AM EDT TUE SEP 1 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 414 AM EDT TUE SEP 1 2015
MUCH OF THE FOCUS ON THE SHORT TERM WILL BE WITH THE WEAK SURFACE
TROUGH DECAYING AS IT MOVES EAST ACROSS THE AREA TODAY AND TONIGHT
AND THE POTENTIAL FOR A FEW SHOWERS/THUNDERSTORMS ALONG IT. WATER
VAPOR IMAGERY AND RAP ANALYSIS SHOW THE UPPER RIDGE AXIS IS SHIFTING
EAST ACROSS LAKE HURON EARLY THIS MORNING...WHICH IS ALLOWING A
PLUME OF MOISTURE STRETCHING FROM NORTHWEST MEXICO TO JAMES BAY TO
SLOWLY MOVE EAST TOWARDS THE AREA. DID SEE A FEW SHOWERS ALONG THE
SURFACE TROUGH AND MOISTURE PLUME EARLIER IN THE NIGHT IN NORTHERN
MINNESOTA BUT THEY HAVE SINCE DISSIPATED. OUT AHEAD OF THE
TROUGH...THE COMBINATION OF VERY RADIATIONAL COOLING AND
SOUTHWESTERLY WINDS PULLING MOIST AIR ACROSS LAKE MICHIGAN HAS
PRODUCED FOG ONCE AGAIN OVER EASTERN UPPER MICHIGAN. THE LOWEST
VISIBILITIES HAVE BEEN RIGHT ALONG THE LAKE MICHIGAN
SHORELINE...WITH VISIBILITIES AT 1/4MI AT TIMES. DID ISSUE A MARINE
DENSE FOG ADVISORY EARLIER IN THE NIGHT BASED OFF THE SATELLITE
COVERAGE OF THE FOG ON LAKE MICHIGAN AND THE VISIBILITY RAPIDLY
FALLING ONCE IT REACHED KISQ. THE REST OF THE AREA HAS SEEN MOSTLY
CLEAR SKIES AND AREAS WHERE THE WINDS HAVE DECOUPLED HAVE SEEN
PATCHY GROUND FOG. EXPECT THAT TO CONTINUE INTO THE FIRST PART OF
THE MORNING HOURS BEFORE LIFTING TO A BRIEF STRATUS DECK AND THEN
DISSIPATING. ON FINAL ITEM TO NOTE FOR THIS MORNING IS THE SCATTERED
BORDERLINE MVFR/VFR CLOUDS IN WESTERN WISCONSIN. THESE HAVE BEEN
SHIFTING TO THE NORTH THIS MORNING AND WILL AID SOME DIURNAL CLOUDS
OVER PORTIONS OF THE AREA TODAY.
PRECIPITATION POTENTIAL IS A LITTLE MORE UP IN THE AIR FOR TODAY AND
LARGELY TIED TO SEVERAL FEATURES COMING TOGETHER IN A NARROW
CORRIDOR THIS AFTERNOON. FIRST...THE MOISTURE PLUME TO THE WEST OF
THE AREA ON WATER VAPOR WILL SHIFT TO THE EAST AND ACROSS THE
WEST/CENTRAL CWA THIS AFTERNOON. WHILE IT LOOKS FAIRLY IMPRESSIVE ON
WV IMAGERY...IT APPEARS THAT THE MODELS ARE DOING FAIRLY WELL ON THE
VERY THIN POCKETS OF MOISTURE WITHIN THAT AREA. SECOND...SOME OF THE
MODELS HAVE HINTS OF A WEAK SHORTWAVE IN EASTERN SOUTH DAKOTA THAT
WILL LIFT TO THE NORTHEAST AND ONLY BRUSH THE WEST/CENTRAL U.P. THIS
AFTERNOON. WHILE MOST OF IT WILL STAY NORTHWEST OF THE LAND
CWA...THERE ARE SOME HINTS AT A SOUTHERN APPENDAGE TO THE SHORTWAVE
THAT MAY WORK WITH THE SURFACE TROUGH AND POCKETS OF MOISTURE AROUND
850MB TO DEVELOP SOME SHOWERS/THUNDERSTORMS THIS AFTERNOON. COARSE
MODELS ARE SHOWING LIMITED DEVELOPMENT...WHILE THE HIGHER RESOLUTION
MODELS (INCLUDING 14KM ECMWF) ARE SHOWING SOME ISOLATED SHOWER
DEVELOPMENT BETWEEN 19-22Z OVER WEST-CENTRAL UPPER MICHIGAN
(GENERALLY FROM KIWD THROUGH BARAGA COUNTY AND INTO NORTHERN
MARQUETTE COUNTY). NCAR WRF ENSEMBLES FOCUS ON THAT AREA TOO FOR
INITIAL DEVELOPMENT BUT THEN EXPAND IT EAST-SOUTHEAST INTO THE
CENTRAL U.P. THIS EVENING (MARQUETTE/ALGER/DELTA AND NRN MENOMINEE).
HAVE KEPT THE POPS CONFINED TO THE AREA IMMEDIATELY AHEAD OF THE
WEAK TROUGH AND OVER THE LAND AREAS OF WEST/CENTRAL UPPER MICHIGAN.
WILL CONTINUE TO SHOW SLIGHT CHANCES BASED OFF THE UNCERTAINTY OF
THE SHORTWAVE BEING CLOSE/STRONG ENOUGH TO HELP THE SHOWERS AND ALSO
THE MARGINAL MOISTURE...ALTHOUGH DID INCLUDE A FEW CHANCES FOR THE
SOUTHERN HOUGHTON AND BARAGA COUNTY AREA DUE TO THE CONSISTENCY IN
THE MODELS ON SOMETHING OCCURRING IN THAT AREA. IN ADDITION...THERE
ARE INDICATIONS OF A VERY NARROW CORRIDOR OF STRONGER 0-6KM BULK
SHEAR (30-35KTS) OVER NORTH CENTRAL UPPER MICHIGAN ALTHOUGH MOST
AREAS WILL BE IN THE 20-25KT RANGE. COMBINING THAT WITH MLCAPE
VALUES OF 1-2K J/KG THIS AFTERNOON...THERE IS THE POTENTIAL FOR A
STRONGER STORM IF ALL OF THE PIECES COME TOGETHER.
THE TROUGH WILL CONTINUE SOUTHEAST AND WEAKEN THROUGH THE NIGHT
TONIGHT...LEADING TO A SUBTLE WIND SHIFT TO THE WEST-NORTHWEST.
SHOWERS SHOULD DISSIPATE THROUGH THE EVENING HOURS OVER THE
NORTHEASTERN PART OF THE CWA AND LEAD TO A PARTLY CLOUDY TO MOSTLY
CLEAR NIGHT. WILL HAVE TO WATCH FOR FOG DEVELOPMENT AGAIN
TONIGHT...ALTHOUGH THE MODELS ARE SHOWING SLIGHTLY DRIER LOW LEVEL
AIR. HAVE INCLUDED PATCHY TO AREAS OF FOG FOR NOW AND A LOT WILL
DEPEND ON THE DRYING BEHIND THE WEAK TROUGH.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 519 AM EDT TUE SEP 1 2015
UPPER LEVEL RIDGE TO START ON WEDNESDAY FM SOUTHWEST CONUS TO THE
NORTHEAST CONUS ALLOWS FOR POSSIBLE AFTN/EVENING SHRA/TSRA WED AND
THU. EXPECT THE RIDGE TO BUILD BACK FM SOUTHERN PLAINS TO THE UPPER
GREAT LAKES/NORTHERN ONTARIO BY LATE THIS WEEK IN RESPONSE TO STRONG
UPPER TROUGH DIGGING FM WESTERN CANADA DOWN THE WESTERN CONUS COAST.
TROUGH WILL CONTINUE DIGGING SOUTH...POSSIBLY AS FAR AS CALIFORNIA
BY THIS WEEKEND WHILE RIDGE EXPANDS OVER REST OF GREAT LAKES AND
NORTHEAST CONUS. AT THE SFC...SLOW MOVING COLD FRONT WILL BE STUCK
OVER THE PLAINS IN BETWEEN THE UPPER TROUGH AND UPPER RIDGE. SINCE
UPPER PATTERN CHANGES LITTLE THIS WEEKEND AND FRONT WILL BE PARALLEL
TO FLOW ALOFT...FRONT WILL STRUGGLE EASTWARD SATURDAY INTO SUNDAY.
SHORTWAVE CURRENTLY OVER CO/NEB/KS INTERSECTION IS FORECAST TO LIFT
NORTHEAST TO UPPER MISSISSIPPI RIVER VALLEY BY 12Z WED AND THEN TO
MOVE OVER WI/UPR MICHIGAN WED AFTN INTO WED NIGHT. MLCAPES FOCUSED
MORE FM DAKOTAS/NORTHERN MN ESE ACROSS WI AND LOWER MICHIGAN. MEAN
LAYER WINDS WNW-W...SO PREFER THE ECMWF/NAM/GEM-REGIONAL SHOWING
MAJORITY OF QPF OVER NORTHERN WI WITH THE SHRA/TSRA. ALSO NORTHERLY
GRADIENT/LAKE BREEZE ENHANCED WINDS OFF LK SUPERIOR WILL STABILIZE
LOW-LEVELS CLOSER TO LK SUPERIOR AND OVER EASTERN CWA. CHANCE POPS
HIGHEST TOWARD WI BORDER. FOR TEMPS...STUCK TOWARD PREVIOUS FORECAST
WITH MID 80S INLAND WEST HALF. COOLER MID-UPR 70S NEAR LK SUPERIOR
WITH ONSHORE WINDS. IF THOSE ONSHORE WINDS START UP QUICKER...COULD
SEE READINGS ENDING UP COOLER THAN FORECAST CURRENTLY SHOWS. KEPT
LINGERING POPS MAINLY SCNTRL ON WED NIGHT AS THE SHORTWAVE DRIFTS
ACROSS AND SINCE SCNTRL WILL BE ON NORTHERN EDGE OF H85 CONVERGENCE
ZONE AND IN A POTENTIAL MID-LEVEL FGEN AREA WITH THE SHORTWAVE.
SUBSIDENCE INCREASES IN WAKE OF SHORTWAVE LATER THURSDAY INTO
FRIDAY...SO FOR MOST PART THINK IT WILL BE MAINLY DRY COUPLE DAYS.
WINDS TURN BACK TO SSE-S WHICH RESULTS IN BETTER CHANCE OF WARMING
FOR ALL AREAS AWAY FM LK MICHIGAN. H85 TEMPS BUMP UP A COUPLE
DEGREES AS WELL BY SO AFTER LOW-MID 80S ON THU...SHOULD SEE AT LEAST
UPR 80S FOR WEST CWA ON FRIDAY AFTN. LOW-MID 80S ELSEWHERE...EXPECT
UPR 70S NEAR LK MICHIGAN. NO CHANGE AT ALL THE HUMID CONDITIONS THAT
REALLY START UP TODAY...WITH DWPNTS SOLIDLY IN THE 60S. THOUGH NOT
IN THE FORECAST THE ENTIRE TIME...CANNOT RULE OUT FOG JUST ABOUT
ANYTIME WEDNESDAY THROUGH FRIDAY ESPECIALLY NEAR THE GREAT LAKES
SHORES WHERE THERE IS SOME ONSHORE WIND COMPONENT. HAVE SEEN THIS
LAST FEW DAYS AND NO REASON TO BELIEVE IT WILL NOT CONTINUE IN AT
LEAST SOME SHAPE OR FORM.
INTO THIS WEEKEND. EVENTUALLY...STRONGER SHORTWAVE TROUGH FORECAST
TO MOVE INTO WESTERN CANADA WILL ACT AS KICKER TO THE TROUGH OVER
THE NORTHWEST CONUS AND PUSH THE COLD FRONT TO THE EAST WHILE
DEVELOPING A SFC LOW ON ITS NORTHERN EDGE AT THE FOREFRONT OF THE
INITIAL UPPER LEVEL TROUGH. ENTIRE SYSTEM MOVES ACROSS UPPER GREAT
LAKES SUNDAY INTO MONDAY. ECMWF IN 3 OF ITS RUNS OVER LAST FEW DAYS
HAS HINTED THAT SHRA/TSRA MAY BREAK OUT WELL AHEAD OF MAIN FRONT
DOWNSTREAM OF SURGE OF 2000 J/KG MUCAPE FM NORTHERN PLAINS TO
NORTHWEST ONTARIO EITHER SATURDAY OR SUNDAY. 850-300MB THICKNESS
LINES WOULD SUPPORT THAT POTENTIAL SHOWING NW-SE FLOW SATURDAY AND W-
E FLOW ON SUNDAY. LATEST ECMWF NOW BUILDS UPPER RIDGE MORE AND HAS
H85 THETA-E RIDGE AS FAR NORTH AS SOUTHERN MANITOBA AND NORTHWEST
ONTARIO FRIDAY NIGHT INTO SATURDAY. IF THIS OCCURRS IT WOULD LIKELY
STAY DRY OVER UPR MICHIGAN FRIDAY NIGHT INTO SATURDAY AS SHORTWAVES
AND ASSOCIATED SHRA/TSRA WOULD STAY WELL TO THE NORTHWEST OF UPR
MICHIGAN/LK SUPERIOR. THEN...ONCE THE SHORTWAVE TROUGH OVER THE
NORTHWEST CONUS MOVES EASTWARD...THERE WOULD BE INCREASING CHANCES
OF SHRA/TSRA AS THE WEEKEND CONCLUDES AND ON INTO LABOR DAY. KEPT
POPS AT SLIGHT CHANCE OVER SOUTH AND EAST FRIDAY NIGHT INTO SATURDAY
NIGHT WITH CHANCE POPS OVER FAR NW CWA. BY SUNDAY...BROUGHT CHANCE
POPS OVER MORE OF THE NORTH CWA BUT STILL KEPT POPS SLIGHT CHANCE AT
BEST OVER SCNTRL FARTHER AWAY FM THE THETA-E RIDGE AND MORE INTO THE
LARGER SCALE RIDGE.
GFS BLOWS COLD FRONT THROUGH QUICKLY SUNDAY NIGHT INTO MONDAY WHILE
ECMWF IS SLOWER MAINLY DUE TO SHOWING MORE OF A CUTOFF UPPER LOW
OVER THE WESTERN CONUS SATURDAY NIGHT INTO SUNDAY. WILL CONTINUE TO
USE CONSENSUS POPS FOR FORECAST WHICH ARE HIGHEST FOR SUN NIGHT INTO
LABOR DAY. STILL LOOKS COOLER FOR SUNDAY AND LABOR DAY...AT LEAST
COMPARED TO WARMTH THIS WEEK. BASED ON TRENDS FM LATEST MODELS...
CONFIDENCE IS LESSENING IN A SIGNIFICANT COOL DOWN NEXT WEEK. STAY
TUNED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 121 AM EDT TUE SEP 1 2015
EXPECT VFR CONDITIONS TO PREVAIL AT THE SITES THROUGH MUCH OF THE
REST OF THE PERIOD. KSAW AND CMX WILL SEE THE POTENTIAL FOR PATCHY
GROUND FOG LATE TONIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 414 AM EDT TUE SEP 1 2015
SOUTHWESTERLY WINDS WILL WEAKEN THROUGH THE DAY TODAY AS A WEAK
SURFACE TROUGH SLOWLY DROPS SOUTHEAST ACROSS LAKE SUPERIOR TODAY
AND TONIGHT. THIS WILL LEAD TO WINDS FALLING BELOW 15KTS THIS
AFTERNOON AND REMAIN THAT WAY INTO THURSDAY AS A HIGH PRESSURE
RIDGE NOSES BACK NORTHWEST INTO THE UPPER GREAT LAKES REGION.
SOUTHERLY FLOW WILL STRENGTHEN FRIDAY INTO THE WEEKEND AHEAD OF A
BROAD LOW PRESSURE TROUGH STRETCHING FROM CENTRAL CANADA TO THE
CENTRAL PLAINS THAT WILL MOVE EAST INTO THE UPPER MISSISSIPPI
VALLEY. FINALLY...EXPECT PATCHY TO AREAS OF FOG TO OCCUR OVER LAKE
SUPERIOR INTO THURSDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
DENSE FOG ADVISORY UNTIL NOON EDT TODAY FOR LMZ248-250.
&&
$$
SHORT TERM...SRF
LONG TERM...JLA
AVIATION...07
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
457 AM EDT TUE SEP 1 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 414 AM EDT TUE SEP 1 2015
MUCH OF THE FOCUS ON THE SHORT TERM WILL BE WITH THE WEAK SURFACE
TROUGH DECAYING AS IT MOVES EAST ACROSS THE AREA TODAY AND TONIGHT
AND THE POTENTIAL FOR A FEW SHOWERS/THUNDERSTORMS ALONG IT. WATER
VAPOR IMAGERY AND RAP ANALYSIS SHOW THE UPPER RIDGE AXIS IS SHIFTING
EAST ACROSS LAKE HURON EARLY THIS MORNING...WHICH IS ALLOWING A
PLUME OF MOISTURE STRETCHING FROM NORTHWEST MEXICO TO JAMES BAY TO
SLOWLY MOVE EAST TOWARDS THE AREA. DID SEE A FEW SHOWERS ALONG THE
SURFACE TROUGH AND MOISTURE PLUME EARLIER IN THE NIGHT IN NORTHERN
MINNESOTA BUT THEY HAVE SINCE DISSIPATED. OUT AHEAD OF THE
TROUGH...THE COMBINATION OF VERY RADIATIONAL COOLING AND
SOUTHWESTERLY WINDS PULLING MOIST AIR ACROSS LAKE MICHIGAN HAS
PRODUCED FOG ONCE AGAIN OVER EASTERN UPPER MICHIGAN. THE LOWEST
VISIBILITIES HAVE BEEN RIGHT ALONG THE LAKE MICHIGAN
SHORELINE...WITH VISIBILITIES AT 1/4MI AT TIMES. DID ISSUE A MARINE
DENSE FOG ADVISORY EARLIER IN THE NIGHT BASED OFF THE SATELLITE
COVERAGE OF THE FOG ON LAKE MICHIGAN AND THE VISIBILITY RAPIDLY
FALLING ONCE IT REACHED KISQ. THE REST OF THE AREA HAS SEEN MOSTLY
CLEAR SKIES AND AREAS WHERE THE WINDS HAVE DECOUPLED HAVE SEEN
PATCHY GROUND FOG. EXPECT THAT TO CONTINUE INTO THE FIRST PART OF
THE MORNING HOURS BEFORE LIFTING TO A BRIEF STRATUS DECK AND THEN
DISSIPATING. ON FINAL ITEM TO NOTE FOR THIS MORNING IS THE SCATTERED
BORDERLINE MVFR/VFR CLOUDS IN WESTERN WISCONSIN. THESE HAVE BEEN
SHIFTING TO THE NORTH THIS MORNING AND WILL AID SOME DIURNAL CLOUDS
OVER PORTIONS OF THE AREA TODAY.
PRECIPITATION POTENTIAL IS A LITTLE MORE UP IN THE AIR FOR TODAY AND
LARGELY TIED TO SEVERAL FEATURES COMING TOGETHER IN A NARROW
CORRIDOR THIS AFTERNOON. FIRST...THE MOISTURE PLUME TO THE WEST OF
THE AREA ON WATER VAPOR WILL SHIFT TO THE EAST AND ACROSS THE
WEST/CENTRAL CWA THIS AFTERNOON. WHILE IT LOOKS FAIRLY IMPRESSIVE ON
WV IMAGERY...IT APPEARS THAT THE MODELS ARE DOING FAIRLY WELL ON THE
VERY THIN POCKETS OF MOISTURE WITHIN THAT AREA. SECOND...SOME OF THE
MODELS HAVE HINTS OF A WEAK SHORTWAVE IN EASTERN SOUTH DAKOTA THAT
WILL LIFT TO THE NORTHEAST AND ONLY BRUSH THE WEST/CENTRAL U.P. THIS
AFTERNOON. WHILE MOST OF IT WILL STAY NORTHWEST OF THE LAND
CWA...THERE ARE SOME HINTS AT A SOUTHERN APPENDAGE TO THE SHORTWAVE
THAT MAY WORK WITH THE SURFACE TROUGH AND POCKETS OF MOISTURE AROUND
850MB TO DEVELOP SOME SHOWERS/THUNDERSTORMS THIS AFTERNOON. COARSE
MODELS ARE SHOWING LIMITED DEVELOPMENT...WHILE THE HIGHER RESOLUTION
MODELS (INCLUDING 14KM ECMWF) ARE SHOWING SOME ISOLATED SHOWER
DEVELOPMENT BETWEEN 19-22Z OVER WEST-CENTRAL UPPER MICHIGAN
(GENERALLY FROM KIWD THROUGH BARAGA COUNTY AND INTO NORTHERN
MARQUETTE COUNTY). NCAR WRF ENSEMBLES FOCUS ON THAT AREA TOO FOR
INITIAL DEVELOPMENT BUT THEN EXPAND IT EAST-SOUTHEAST INTO THE
CENTRAL U.P. THIS EVENING (MARQUETTE/ALGER/DELTA AND NRN MENOMINEE).
HAVE KEPT THE POPS CONFINED TO THE AREA IMMEDIATELY AHEAD OF THE
WEAK TROUGH AND OVER THE LAND AREAS OF WEST/CENTRAL UPPER MICHIGAN.
WILL CONTINUE TO SHOW SLIGHT CHANCES BASED OFF THE UNCERTAINTY OF
THE SHORTWAVE BEING CLOSE/STRONG ENOUGH TO HELP THE SHOWERS AND ALSO
THE MARGINAL MOISTURE...ALTHOUGH DID INCLUDE A FEW CHANCES FOR THE
SOUTHERN HOUGHTON AND BARAGA COUNTY AREA DUE TO THE CONSISTENCY IN
THE MODELS ON SOMETHING OCCURRING IN THAT AREA. IN ADDITION...THERE
ARE INDICATIONS OF A VERY NARROW CORRIDOR OF STRONGER 0-6KM BULK
SHEAR (30-35KTS) OVER NORTH CENTRAL UPPER MICHIGAN ALTHOUGH MOST
AREAS WILL BE IN THE 20-25KT RANGE. COMBINING THAT WITH MLCAPE
VALUES OF 1-2K J/KG THIS AFTERNOON...THERE IS THE POTENTIAL FOR A
STRONGER STORM IF ALL OF THE PIECES COME TOGETHER.
THE TROUGH WILL CONTINUE SOUTHEAST AND WEAKEN THROUGH THE NIGHT
TONIGHT...LEADING TO A SUBTLE WIND SHIFT TO THE WEST-NORTHWEST.
SHOWERS SHOULD DISSIPATE THROUGH THE EVENING HOURS OVER THE
NORTHEASTERN PART OF THE CWA AND LEAD TO A PARTLY CLOUDY TO MOSTLY
CLEAR NIGHT. WILL HAVE TO WATCH FOR FOG DEVELOPMENT AGAIN
TONIGHT...ALTHOUGH THE MODELS ARE SHOWING SLIGHTLY DRIER LOW LEVEL
AIR. HAVE INCLUDED PATCHY TO AREAS OF FOG FOR NOW AND A LOT WILL
DEPEND ON THE DRYING BEHIND THE WEAK TROUGH.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 456 AM EDT TUE SEP 1 2015
UPPER LEVEL RIDGE TO START ON WEDNESDAY FM SOUTHWEST CONUS TO THE
NORTHEAST CONUS ALLOWS FOR POSSIBLE AFTN/EVENING SHRA/TSRA WED AND
THU. EXPECT THE RIDGE TO BUILD BACK FM SOUTHERN PLAINS TO THE UPPER
GREAT LAKES/NORTHERN ONTARIO BY LATE THIS WEEK IN RESPONSE TO STRONG
UPPER TROUGH DIGGING FM WESTERN CANADA DOWN THE WESTERN CONUS COAST.
TROUGH WILL CONTINUE DIGGING SOUTH...POSSIBLY AS FAR AS CALIFORNIA
BY THIS WEEKEND WHILE RIDGE EXPANDS OVER REST OF GREAT LAKES AND
NORTHEAST CONUS. AT THE SFC...SLOW MOVING COLD FRONT WILL BE STUCK
OVER THE PLAINS IN BETWEEN THE UPPER TROUGH AND UPPER RIDGE. SINCE
UPPER PATTERN CHANGES LITTLE THIS WEEKEND AND FRONT WILL BE PARALLEL
TO FLOW ALOFT...FRONT WILL STRUGGLE EASTWARD SATURDAY INTO SUNDAY.
SHORTWAVE CURRENTLY OVER CO/NEB/KS INTERSECTION IS FORECAST TO LIFT
NORTHEAST TO UPPER MISSISSIPPI RIVER VALLEY BY 12Z WED AND THEN TO
MOVE OVER WI/UPR MICHIGAN WED AFTN INTO WED NIGHT. MLCAPES FOCUSED
MORE FM DAKOTAS/NORTHERN MN ESE ACROSS WI AND LOWER MICHIGAN. MEAN
LAYER WINDS WNW-W...SO PREFER THE ECMWF/NAM/GEM-REGIONAL SHOWING
MAJORITY OF QPF OVER NORTHERN WI WITH THE SHRA/TSRA. ALSO NORTHERLY
GRADIENT/LAKE BREEZE ENHANCED WINDS OFF LK SUPERIOR WILL STABILIZE
LOW-LEVELS CLOSER TO LK SUPERIOR AND OVER EASTERN CWA. CHANCE POPS
HIGHEST TOWARD WI BORDER. FOR TEMPS...STUCK TOWARD PREVIOUS FORECAST
WITH MID 80S INLAND WEST HALF. COOLER MID-UPR 70S NEAR LK SUPERIOR
WITH ONSHORE WINDS. IF THOSE ONSHORE WINDS START UP QUICKER...COULD
SEE READINGS ENDING UP COOLER THAN FORECAST CURRENTLY SHOWS. KEPT
LINGERING POPS MAINLY SCNTRL AS THE SHORTWAVE DRIFTS ACROSS AND
SINCE SCNTRL WILL BE ON NORTHERN EDGE OF H85 CONVERGENCE ZONE AND
IN A POTENTIAL MID-LEVEL FGEN AREA WITH THE SHORTWAVE.
SUBSIDENCE INCREASES IN WAKE OF SHORTWAVE FOR FRIDAY...SO THINK IT
WILL BE MAINLY A DRY DAY. WINDS TURN BACK TO SSE-S WHICH RESULTS IN
BETTER CHANCE OF WARMING FOR ALL AREAS AWAY FM LK MICHIGAN. H85
TEMPS BUMP UP A COUPLE DEGREES AS WELL SO SHOULD SEE AT LEAST UPR
80S FOR WEST CWA ON FRIDAY AFTN. LOW-MID 80S ELSEWHERE...EXPECT UPR
70S NEAR LK MICHIGAN. NO CHANGE AT ALL THE HUMID CONDITIONS THAT
REALLY START UP TODAY...WITH DWPNTS SOLIDLY IN THE 60S. THOUGH NOT
IN THE FORECAST THE ENTIRE TIME...CANNOT RULE OUT FOG JUST ABOUT
ANYTIME WEDNESDAY THROUGH FRIDAY ESPECIALLY NEAR THE GREAT LAKES
SHORES WHERE THERE IS SOME ONSHORE WIND COMPONENT. HAVE SEEN THIS
LAST FEW DAYS AND NO REASON TO BELIEVE IT WILL NOT CONTINUE IN AT
LEAST SOME SHAPE OR FORM.
INTO THIS WEEKEND. EVENTUALLY...STRONGER SHORTWAVE TROUGH FORECAST
TO MOVE INTO WESTERN CANADA WILL ACT AS KICKER TO THE TROUGH OVER
THE NORTHWEST CONUS AND PUSH THE COLD FRONT TO THE EAST WHILE
DEVELOPING A SFC LOW ON ITS NORTHERN EDGE AT THE FOREFRONT OF THE
INITIAL UPPER LEVEL TROUGH. ENTIRE SYSTEM MOVES ACROSS UPPER GREAT
LAKES SUNDAY INTO MONDAY. ECMWF IN 3 OF ITS RUNS OVER LAST FEW DAYS
HAS HINTED THAT SHRA/TSRA MAY BREAK OUT WELL AHEAD OF MAIN FRONT
DOWNSTREAM OF SURGE OF 2000 J/KG MUCAPE FM NORTHERN PLAINS TO
NORTHWEST ONTARIO EITHER SATURDAY OR SUNDAY. 850-300MB THICKNESS
LINES WOULD SUPPORT THAT POTENTIAL SHOWING NW-SE FLOW SATURDAY AND W-
E FLOW ON SUNDAY. LATEST ECMWF NOW BUILDS UPPER RIDGE MORE AND HAS
H85 THETA-E RIDGE AS FAR NORTH AS SOUTHERN MANITOBA AND NORTHWEST
ONTARIO FRIDAY NIGHT INTO SATURDAY. IF THIS OCCURRS IT WOULD LIKELY
STAY DRY OVER UPR MICHIGAN FRIDAY NIGHT INTO SATURDAY AS SHORTWAVES
AND ASSOCIATED SHRA/TSRA WOULD STAY WELL TO THE NORTHWEST OF UPR
MICHIGAN/LK SUPERIOR. THEN...ONCE THE SHORTWAVE TROUGH OVER THE
NORTHWEST CONUS MOVES EASTWARD...THERE WOULD BE INCREASING CHANCES
OF SHRA/TSRA AS THE WEEKEND CONCLUDES AND ON INTO LABOR DAY. KEPT
POPS AT SLIGHT CHANCE OVER SOUTH AND EAST FRIDAY NIGHT INTO SATURDAY
NIGHT WITH CHANCE POPS OVER FAR NW CWA. BY SUNDAY...BROUGHT CHANCE
POPS OVER MORE OF THE NORTH CWA BUT STILL KEPT POPS SLIGHT CHANCE AT
BEST OVER SCNTRL FARTHER AWAY FM THE THETA-E RIDGE AND MORE INTO THE
LARGER SCALE RIDGE.
GFS BLOWS COLD FRONT THROUGH QUICKLY SUNDAY NIGHT INTO MONDAY WHILE
ECMWF IS SLOWER MAINLY DUE TO SHOWING MORE OF A CUTOFF UPPER LOW
OVER THE WESTERN CONUS SATURDAY NIGHT INTO SUNDAY. WILL CONTINUE TO
USE CONSENSUS POPS FOR FORECAST WHICH ARE HIGHEST FOR SUN NIGHT INTO
LABOR DAY. STILL LOOKS COOLER FOR SUNDAY AND LABOR DAY...AT LEAST
COMPARED TO WARMTH THIS WEEK. BASED ON TRENDS FM LATEST MODELS...
CONFIDENCE IS LESSENING IN A SIGNIFICANT COOL DOWN NEXT WEEK. STAY
TUNED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 121 AM EDT TUE SEP 1 2015
EXPECT VFR CONDITIONS TO PREVAIL AT THE SITES THROUGH MUCH OF THE
REST OF THE PERIOD. KSAW AND CMX WILL SEE THE POTENTIAL FOR PATCHY
GROUND FOG LATE TONIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 414 AM EDT TUE SEP 1 2015
SOUTHWESTERLY WINDS WILL WEAKEN THROUGH THE DAY TODAY AS A WEAK
SURFACE TROUGH SLOWLY DROPS SOUTHEAST ACROSS LAKE SUPERIOR TODAY
AND TONIGHT. THIS WILL LEAD TO WINDS FALLING BELOW 15KTS THIS
AFTERNOON AND REMAIN THAT WAY INTO THURSDAY AS A HIGH PRESSURE
RIDGE NOSES BACK NORTHWEST INTO THE UPPER GREAT LAKES REGION.
SOUTHERLY FLOW WILL STRENGTHEN FRIDAY INTO THE WEEKEND AHEAD OF A
BROAD LOW PRESSURE TROUGH STRETCHING FROM CENTRAL CANADA TO THE
CENTRAL PLAINS THAT WILL MOVE EAST INTO THE UPPER MISSISSIPPI
VALLEY. FINALLY...EXPECT PATCHY TO AREAS OF FOG TO OCCUR OVER LAKE
SUPERIOR INTO THURSDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
DENSE FOG ADVISORY UNTIL NOON EDT TODAY FOR LMZ248-250.
&&
$$
SHORT TERM...SRF
LONG TERM...JLA
AVIATION...07
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
415 AM EDT TUE SEP 1 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 414 AM EDT TUE SEP 1 2015
MUCH OF THE FOCUS ON THE SHORT TERM WILL BE WITH THE WEAK SURFACE
TROUGH DECAYING AS IT MOVES EAST ACROSS THE AREA TODAY AND TONIGHT
AND THE POTENTIAL FOR A FEW SHOWERS/THUNDERSTORMS ALONG IT. WATER
VAPOR IMAGERY AND RAP ANALYSIS SHOW THE UPPER RIDGE AXIS IS SHIFTING
EAST ACROSS LAKE HURON EARLY THIS MORNING...WHICH IS ALLOWING A
PLUME OF MOISTURE STRETCHING FROM NORTHWEST MEXICO TO JAMES BAY TO
SLOWLY MOVE EAST TOWARDS THE AREA. DID SEE A FEW SHOWERS ALONG THE
SURFACE TROUGH AND MOISTURE PLUME EARLIER IN THE NIGHT IN NORTHERN
MINNESOTA BUT THEY HAVE SINCE DISSIPATED. OUT AHEAD OF THE
TROUGH...THE COMBINATION OF VERY RADIATIONAL COOLING AND
SOUTHWESTERLY WINDS PULLING MOIST AIR ACROSS LAKE MICHIGAN HAS
PRODUCED FOG ONCE AGAIN OVER EASTERN UPPER MICHIGAN. THE LOWEST
VISIBILITIES HAVE BEEN RIGHT ALONG THE LAKE MICHIGAN
SHORELINE...WITH VISIBILITIES AT 1/4MI AT TIMES. DID ISSUE A MARINE
DENSE FOG ADVISORY EARLIER IN THE NIGHT BASED OFF THE SATELLITE
COVERAGE OF THE FOG ON LAKE MICHIGAN AND THE VISIBILITY RAPIDLY
FALLING ONCE IT REACHED KISQ. THE REST OF THE AREA HAS SEEN MOSTLY
CLEAR SKIES AND AREAS WHERE THE WINDS HAVE DECOUPLED HAVE SEEN
PATCHY GROUND FOG. EXPECT THAT TO CONTINUE INTO THE FIRST PART OF
THE MORNING HOURS BEFORE LIFTING TO A BRIEF STRATUS DECK AND THEN
DISSIPATING. ON FINAL ITEM TO NOTE FOR THIS MORNING IS THE SCATTERED
BORDERLINE MVFR/VFR CLOUDS IN WESTERN WISCONSIN. THESE HAVE BEEN
SHIFTING TO THE NORTH THIS MORNING AND WILL AID SOME DIURNAL CLOUDS
OVER PORTIONS OF THE AREA TODAY.
PRECIPITATION POTENTIAL IS A LITTLE MORE UP IN THE AIR FOR TODAY AND
LARGELY TIED TO SEVERAL FEATURES COMING TOGETHER IN A NARROW
CORRIDOR THIS AFTERNOON. FIRST...THE MOISTURE PLUME TO THE WEST OF
THE AREA ON WATER VAPOR WILL SHIFT TO THE EAST AND ACROSS THE
WEST/CENTRAL CWA THIS AFTERNOON. WHILE IT LOOKS FAIRLY IMPRESSIVE ON
WV IMAGERY...IT APPEARS THAT THE MODELS ARE DOING FAIRLY WELL ON THE
VERY THIN POCKETS OF MOISTURE WITHIN THAT AREA. SECOND...SOME OF THE
MODELS HAVE HINTS OF A WEAK SHORTWAVE IN EASTERN SOUTH DAKOTA THAT
WILL LIFT TO THE NORTHEAST AND ONLY BRUSH THE WEST/CENTRAL U.P. THIS
AFTERNOON. WHILE MOST OF IT WILL STAY NORTHWEST OF THE LAND
CWA...THERE ARE SOME HINTS AT A SOUTHERN APPENDAGE TO THE SHORTWAVE
THAT MAY WORK WITH THE SURFACE TROUGH AND POCKETS OF MOISTURE AROUND
850MB TO DEVELOP SOME SHOWERS/THUNDERSTORMS THIS AFTERNOON. COARSE
MODELS ARE SHOWING LIMITED DEVELOPMENT...WHILE THE HIGHER RESOLUTION
MODELS (INCLUDING 14KM ECMWF) ARE SHOWING SOME ISOLATED SHOWER
DEVELOPMENT BETWEEN 19-22Z OVER WEST-CENTRAL UPPER MICHIGAN
(GENERALLY FROM KIWD THROUGH BARAGA COUNTY AND INTO NORTHERN
MARQUETTE COUNTY). NCAR WRF ENSEMBLES FOCUS ON THAT AREA TOO FOR
INITIAL DEVELOPMENT BUT THEN EXPAND IT EAST-SOUTHEAST INTO THE
CENTRAL U.P. THIS EVENING (MARQUETTE/ALGER/DELTA AND NRN MENOMINEE).
HAVE KEPT THE POPS CONFINED TO THE AREA IMMEDIATELY AHEAD OF THE
WEAK TROUGH AND OVER THE LAND AREAS OF WEST/CENTRAL UPPER MICHIGAN.
WILL CONTINUE TO SHOW SLIGHT CHANCES BASED OFF THE UNCERTAINTY OF
THE SHORTWAVE BEING CLOSE/STRONG ENOUGH TO HELP THE SHOWERS AND ALSO
THE MARGINAL MOISTURE...ALTHOUGH DID INCLUDE A FEW CHANCES FOR THE
SOUTHERN HOUGHTON AND BARAGA COUNTY AREA DUE TO THE CONSISTENCY IN
THE MODELS ON SOMETHING OCCURRING IN THAT AREA. IN ADDITION...THERE
ARE INDICATIONS OF A VERY NARROW CORRIDOR OF STRONGER 0-6KM BULK
SHEAR (30-35KTS) OVER NORTH CENTRAL UPPER MICHIGAN ALTHOUGH MOST
AREAS WILL BE IN THE 20-25KT RANGE. COMBINING THAT WITH MLCAPE
VALUES OF 1-2K J/KG THIS AFTERNOON...THERE IS THE POTENTIAL FOR A
STRONGER STORM IF ALL OF THE PIECES COME TOGETHER.
THE TROUGH WILL CONTINUE SOUTHEAST AND WEAKEN THROUGH THE NIGHT
TONIGHT...LEADING TO A SUBTLE WIND SHIFT TO THE WEST-NORTHWEST.
SHOWERS SHOULD DISSIPATE THROUGH THE EVENING HOURS OVER THE
NORTHEASTERN PART OF THE CWA AND LEAD TO A PARTLY CLOUDY TO MOSTLY
CLEAR NIGHT. WILL HAVE TO WATCH FOR FOG DEVELOPMENT AGAIN
TONIGHT...ALTHOUGH THE MODELS ARE SHOWING SLIGHTLY DRIER LOW LEVEL
AIR. HAVE INCLUDED PATCHY TO AREAS OF FOG FOR NOW AND A LOT WILL
DEPEND ON THE DRYING BEHIND THE WEAK TROUGH.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 426 PM EDT MON AUG 31 2015
MORE 80S ARE ON THE WAY THROUGH AT LEAST SATURDAY. THE 500MB RIDGE
SET UP FROM W TX-LOWER MI...EXTENDING UP THROUGH HUDSON BAY WILL
FLATTEN OUT ONLY SLIGHTLY...BEFORE REBOUNDING OVER THE UPPER GREAT
LAKES WEDNESDAY NIGHT THROUGH AT LEAST SATURDAY.
WE WILL HAVE A LONG STRETCH OF TEMPERATURES AT OR ABOVE
80F...PROBABLY 8 DAYS IN TOTAL. IT WILL LIKELY END UP THE LONGEST
STRETCH IN 2 YEARS...AND TIED FOR THE LONGEST STRETCH IN 9 YEARS.
THE LAST TIME WE HAD MORE THAN 7 DAYS IN A ROW WAS IN 2006.
ALTHOUGH A NEARING SFC TROUGH TUESDAY NIGHT WILL KEEP LOW POPS OVER
MAINLY E LAKE SUPERIOR...IT WILL WILL HAVE TO OVERCOME PLENTY OF DRY
AIR. PW VALUES DO INCREASE TO 1.7 TO NEAR 2IN E.
ANY WIDESPREAD PRECIP WILL LIKELY HOLD OFF UNTIL SUNDAY OR EVEN
SUNDAY NIGHT UNTIL MONDAY. THE GFS IS A BIT SLOWER THAN THEN ECMWF.
THE APEX OF THE 500MB RIDGE WILL SHIFT W ACROSS THE LOWER GREAT
LAKES AND NEW ENGLAND STATES FOR THE LATTER HALF OF THE
WEEKEND...WITH SW FLOW MOVING INTO OUR AREA. TIMING OF THE NEXT
500MB LOW OR SIGNIFICANT WAVE EJECTING OUT OF THE W TROUGH IS STILL
UNCERTAIN. HOWEVER...INITIAL LOOKS SHOW THAT NEXT TUESDAY OR
WEDNESDAY COULD GIVE US A BETTER CHANCE OF SOME COOLER
AIR...ALTHOUGH IT MAY BE SHORT LIVED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 121 AM EDT TUE SEP 1 2015
EXPECT VFR CONDITIONS TO PREVAIL AT THE SITES THROUGH MUCH OF THE
REST OF THE PERIOD. KSAW AND CMX WILL SEE THE POTENTIAL FOR PATCHY
GROUND FOG LATE TONIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 414 AM EDT TUE SEP 1 2015
SOUTHWESTERLY WINDS WILL WEAKEN THROUGH THE DAY TODAY AS A WEAK
SURFACE TROUGH SLOWLY DROPS SOUTHEAST ACROSS LAKE SUPERIOR TODAY
AND TONIGHT. THIS WILL LEAD TO WINDS FALLING BELOW 15KTS THIS
AFTERNOON AND REMAIN THAT WAY INTO THURSDAY AS A HIGH PRESSURE
RIDGE NOSES BACK NORTHWEST INTO THE UPPER GREAT LAKES REGION.
SOUTHERLY FLOW WILL STRENGTHEN FRIDAY INTO THE WEEKEND AHEAD OF A
BROAD LOW PRESSURE TROUGH STRETCHING FROM CENTRAL CANADA TO THE
CENTRAL PLAINS THAT WILL MOVE EAST INTO THE UPPER MISSISSIPPI
VALLEY. FINALLY...EXPECT PATCHY TO AREAS OF FOG TO OCCUR OVER LAKE
SUPERIOR INTO THURSDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
DENSE FOG ADVISORY UNTIL NOON EDT TODAY FOR LMZ248-250.
&&
$$
SHORT TERM...SRF
LONG TERM...KF
AVIATION...07
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
122 AM EDT TUE SEP 1 2015
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 418 PM EDT MON AUG 31 2015
WV IMAGERY AND RAP ANALYSIS INDICATED A PROMINENT MID/UPEPR LEVEL
RIDGE FROM NM INTO THE GREAT LAKES RESULSTING IN SW FLOW FROM THE
CNTRL ROCKIES INTO THE UPPER MS VALLEY. A WELL-DEFINED SHORTWAVE
TROUGH OVER SRN MANITOBA WAS LIFTING TO THE NE. AT THE SFC...SSW
FLOW PREAVILED ACROSS THE UPPER MS VALLEY AND WRN ALKES BETWEEN HIGH
PRES OVER THE CNTRL LAKES AND A COLD FRONT EXTENDING FROM THE SE
CORNER OF MANITOBA INTO ERN SD. MOST OF THE FOG FROM EARLIER TODAY
HAS BURNED OFF EXCEPT OVER THE FAR SE ALONG LAKE MI NEAR KISQ.
OTHERWISE...MOSTLY SUNNY SKIES PREVAILED WITH TEMPS AWAY FROM LAKE
MI INTO THE MID TO UPPER 80S.
TONIGHT...SEVERAL MODELS SUGGEST SOME SHRA/TSRA MAY DEVELOP FROM MN
INTO NW WI OR WRN LAKE SUPEROR AS AN AXIS OF HIGHER MOISTURE AND THE
TAIL OF THE MANITOBA SHRTWV SLIDES TO THE EAST. HOWEVER...THE AMOUNT
OF CAPPING AND ONLY WEAK MID LEVEL QVECTOR CONV...EXPECT ANY
COVERAGE TO BE MINIMAL AND REMAIN TO THE WEST OF THE CWA. ALTHOUGH
BNDRY LAYER WINDS WILL BE HIGHER THAN LAST NIGHT...EXPECT PATCHY/AREAS
TO REDEVELOP OVER MAINLY THE SE HALF.
TUE...PCPN CHANCES WILL INCREASE AS THE MOISTURE AXIS AND WEAK
TROUGH SAG INTO UPPER MICHIGAN. ALTHOUGH SOME PCPN MAY BE POSSIBLE
IN THE MORNING...EXPECT BETTER SHRA/TSRA CHANCES BY AFTERNOON WITH
INCREASED DAYTIME HEATING AND SUPPORT FROM DEVELOPING LAKE BREEZE
BOUNDARIES. TSRA WILL BE POSSIBLE WITH MLCAPE VALUES INTO THE 1K-2K
J/KG RANGE. HOWEVER WITH 0-6KM SHEAR VALUES ONLY AROUND 25-30 KNOTS
AND WITH WBZ HEGHTS NEAR 13K FT...SEVERE TS CHANCES WILL BE MINIMAL.
THE MAIN HAZARDS WILL BE BRIEF HEAVY RAIN AND GUSTY WINDS. EVEN WITH
INCREASED CLOUD COVER...TEMPS SHOULD AGAIN CLIMB INTO THE MID TO
UPPER 80S.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 426 PM EDT MON AUG 31 2015
MORE 80S ARE ON THE WAY THROUGH AT LEAST SATURDAY. THE 500MB RIDGE
SET UP FROM W TX-LOWER MI...EXTENDING UP THROUGH HUDSON BAY WILL
FLATTEN OUT ONLY SLIGHTLY...BEFORE REBOUNDING OVER THE UPPER GREAT
LAKES WEDNESDAY NIGHT THROUGH AT LEAST SATURDAY.
WE WILL HAVE A LONG STRETCH OF TEMPERATURES AT OR ABOVE
80F...PROBABLY 8 DAYS IN TOTAL. IT WILL LIKELY END UP THE LONGEST
STRETCH IN 2 YEARS...AND TIED FOR THE LONGEST STRETCH IN 9 YEARS.
THE LAST TIME WE HAD MORE THAN 7 DAYS IN A ROW WAS IN 2006.
ALTHOUGH A NEARING SFC TROUGH TUESDAY NIGHT WILL KEEP LOW POPS OVER
MAINLY E LAKE SUPERIOR...IT WILL WILL HAVE TO OVERCOME PLENTY OF DRY
AIR. PW VALUES DO INCREASE TO 1.7 TO NEAR 2IN E.
ANY WIDESPREAD PRECIP WILL LIKELY HOLD OFF UNTIL SUNDAY OR EVEN
SUNDAY NIGHT UNTIL MONDAY. THE GFS IS A BIT SLOWER THAN THEN ECMWF.
THE APEX OF THE 500MB RIDGE WILL SHIFT W ACROSS THE LOWER GREAT
LAKES AND NEW ENGLAND STATES FOR THE LATTER HALF OF THE
WEEKEND...WITH SW FLOW MOVING INTO OUR AREA. TIMING OF THE NEXT
500MB LOW OR SIGNIFICANT WAVE EJECTING OUT OF THE W TROUGH IS STILL
UNCERTAIN. HOWEVER...INITIAL LOOKS SHOW THAT NEXT TUESDAY OR
WEDNESDAY COULD GIVE US A BETTER CHANCE OF SOME COOLER
AIR...ALTHOUGH IT MAY BE SHORT LIVED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 121 AM EDT TUE SEP 1 2015
EXPECT VFR CONDITIONS TO PREVAIL AT THE SITES THROUGH MUCH OF THE
REST OF THE PERIOD. KSAW AND CMX WILL SEE THE POTENTIAL FOR PATCHY
GROUND FOG LATE TONIGHT.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 418 PM EDT MON AUG 31 2015
EXPECT SOUTH-SOUTHWESTERLY WINDS TO CONTINUE OVER LAKE SUPERIOR
THROUGH MUCH OF THE WEEK...AS THE AREA IS ON THE NORTHWESTERN EDGE
OF A HIGH PRESSURE RIDGE CENTERED OVER THE CENTRAL APPALACHIANS.
THERE WILL BE A BRIEF INCREASE IN THE SOUTHWESTERLY WINDS
TONIGHT...UP TO 20KTS...AS A LOW PRESSURE SYSTEM MOVES THROUGH NW
ONTARIO TO SOUTHERN HUDSON BAY BY TUE MORNING. AT THIS TIME...THE
MARINE LAYER SHOULD KEEP THE WINDS IN CHECK...BUT COULD SEE HIGHER
GUSTS TO 25 OR EVEN 30KTS AT A FEW OF THE HIGHER PLATFORMS TOWARDS
ISLE ROYALE. OTHERWISE...EXPECT WINDS TO BE BELOW 20KTS FOR THE REST
OF THE PERIOD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
DENSE FOG ADVISORY UNTIL NOON EDT TODAY FOR LMZ248-250.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
ISSUED BY NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
1231 PM CDT TUE SEP 1 2015
.SHORT TERM: (THROUGH LATE THIS AFTERNOON)
ISSUED AT 330 AM CDT TUE SEP 1 2015
PRIMARY CONCERN FOR TODAY IS THUNDERSTORM CHANCES THROUGHOUT THE
DAY. SHORT RANGE GUIDANCE CONTINUES TO WANT TO BREAK OUT ISOLATED
TO WIDELY SCATTERED CONVECTION THIS MORNING ALONG A LINE FROM NEAR
WEST PLAINS MISSOURI TO SALEM ILLINOIS. THIS IS IN THE VICINITY OF
A MID-UPPER LEVEL VORTICITY CHAIN STRETCHING UP FROM EAST TEXAS
THROUGH ARKANSAS AND SOUTHEAST MISSOURI INTO INDIANA. RAP SHOWS
SOME WEAK LOW LEVEL WARM ADVECTION AND MOISTURE CONVERGENCE UNDER
THE VORT CHAIN THROUGH MID MORNING AND LATEST IR SAT-PICS SHOW WHAT
LOOKS LIKE ALTO-CUMULUS BREAKING OUT IN THE VICINITY OF THE
AFOREMENTIONED LINE. INDEED...SURFACE OBS SHOW DEVELOPING CEILINGS
BETWEEN 8000-10,000 FT AND AN ISOLATED CELL HAS RECENTLY POPPED UP
ON RADAR IN CENTRAL ILLINOIS. SHOULD SEE THIS ACTIVITY CONTINUE TO
PERCOLATE THROUGH MID MORNING BEFORE WANING. THINK THERE WILL BE
SOME REDEVELOPMENT THIS AFTERNOON IN THE VICINITY OF THAT VORT CHAIN
WHERE THE MID LEVEL CAPPING AND UPPER LEVEL SUBSIDENCE WILL BE
WEAKEST. COVERAGE WILL LIKELY BE WIDELY SCATTERED AT BEST. WITH
RELATIVELY STAGNANT PATTERN IN PLACE, EXPECT HIGHS TO BE SIMILAR TO
YESTERDAY`S...PERHAPS A DEGREE OR TWO WARMER.
CARNEY
.LONG TERM: (TONIGHT THROUGH MONDAY)
ISSUED AT 355 AM CDT TUE SEP 1 2015
EXPECT ANY THUNDERSTORMS THAT DEVELOP THIS AFTERNOON TO QUICKLY
DISSIPATE EARLY THIS EVENING AS WE LOSE DAYTIME HEATING. WHILE THE
SHEAR AXIS/VORTICITY CHAIN IN THE MID AND UPPER LEVELS WILL STILL BE
IN THE VICINITY OF THE AREA TONIGHT AND WEDNESDAY, IT LOOKS LIKE IT
WILL BE WEAKENING WITH TIME AS WELL AS DIPPING FURTHER SOUTH ACROSS
FAR SOUTHEAST MISSOURI, NORTHEAST ARKANSAS, TENNESSEE, AND KENTUCKY.
I CAN`T TOTALLY RULE OUT AN ISOLATED SHOWER OR THUNDERSTORM
TONIGHT INTO WEDNESAY, BUT THINK PRECIP CHANCES ARE LOW ENOUGH IN
OUR CWFA TO KEEP POPS BELOW MENTIONABLE LEVELS AT THIS TIME.
THE REST OF THE FORECAST AT LEAST THROUGH THE WEEKEND LOOKS PRETTY
UNEVENTFUL. LATE SUMMER-LIKE PATTERN WITH STRONG RIDGING THROUGH
THE DEPTH OF THE TROPOSPHERE SHOULD KEEP THE AREA HOT AND DRY
THROUGH THE WEEKEND. HIGHS LOOK TO BE IN THE LOW TO MID 90S WITH
LOWS GENERALLY IN THE LOW TO MID 70S. DEWPOINT TEMPERATURES SHOULD
STAY IN THE UPPER 60S TO LOW 70S ACROSS THE AREA THOUGH THE PERIOD.
WHILE THIS WILL FEEL WARM AND HUMID, CURRENT THINKING IS THAT HEAT
HEADLINES WILL NOT BE NEEDED. A PATTERN SHIFT WITH SOME COOLER
TEMPERATURES MAY BE IN THE FORECAST NEXT WEEK, BUT GFS AND ECMWF
AREN`T EXACTLY IN GOOD AGREEMENT ON THIS. REGARDLESS...THE SHIFT
(IF IT OCCURS) WILL LIKELY BE TOWARD THE MIDDLE OF THE WEEK; SO HAVE
KEPT WARM TEMPERATURES GOING THROUGH MONDAY.
CARNEY
&&
.AVIATION: (FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1226 PM CDT TUE SEP 1 2015
VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH THE FORECAST PERIOD
ACROSS THE MAJORITY OF THE REGION. SCATTERED CUMULUS WITH BASES
AROUND 5 KFT WILL CONTINUE TO DEVELOP THROUGHOUT THE SOUTHERN HALF
OF THE FORECAST AREA...AND COULD EVEN SEE A FEW POP UP SHOWERS OR
ISOLATED THUNDERSTORMS THIS AFTERNOON MAINLY SOUTH OF THE TERMINALS.
CLOUD COVER AND ANY POTENTIAL FOR PRECIPITATION WILL DISSIPATE AROUND
01Z-02Z...LEAVING BEHIND CLEAR SKIES AND LIGHT SOUTHERLY WINDS.
SPECIFICS FOR KSTL: VFR CONDITIONS EXPECTED. A FEW ISOLATED SHOWERS
OR THUNDERSTORMS COULD DEVELOP SOUTH OF KSTL AND WILL MONITOR CLOSELY
IN CASE THESE ENCROACH ON THE VICINITY OF THE TERMINAL...BUT FOR NOW
THE PROBABILITY IS TOO LOW FOR MENTION IN THE TAF. WINDS WILL VARY
BETWEEN 210 AND 230 DEGREES AT SPEEDS AROUND 7 TO 8 KTS THROUGH EARLY
EVENING...THEN WILL BACK TO THE SOUTH AND DECREASE TO SPEEDS AROUND 5
KTS.
LAFLIN
&&
.PRELIMINARY POINT TEMPS/POPS:
SAINT LOUIS 93 78 92 78 / 10 10 5 5
QUINCY 93 69 91 70 / 5 5 5 5
COLUMBIA 93 69 92 70 / 10 10 5 5
JEFFERSON CITY 93 69 92 70 / 10 10 5 5
SALEM 90 70 90 70 / 20 10 10 5
FARMINGTON 90 68 91 69 / 20 20 5 5
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
642 AM CDT TUE SEP 1 2015
.SHORT TERM: (THROUGH LATE THIS AFTERNOON)
ISSUED AT 330 AM CDT TUE SEP 1 2015
PRIMARY CONCERN FOR TODAY IS THUNDERSTORM CHANCES THROUGHOUT THE
DAY. SHORT RANGE GUIDANCE CONTINUES TO WANT TO BREAK OUT ISOLATED
TO WIDELY SCATTERED CONVECTION THIS MORNING ALONG A LINE FROM NEAR
WEST PLAINS MISSOURI TO SALEM ILLINOIS. THIS IS IN THE VICINITY OF
A MID-UPPER LEVEL VORTICITY CHAIN STRETCHING UP FROM EAST TEXAS
THROUGH ARKANSAS AND SOUTHEAST MISSOURI INTO INDIANA. RAP SHOWS
SOME WEAK LOW LEVEL WARM ADVECTION AND MOISTURE CONVERGENCE UNDER
THE VORT CHAIN THROUGH MID MORNING AND LATEST IR SAT-PICS SHOW WHAT
LOOKS LIKE ALTO-CUMULUS BREAKING OUT IN THE VICINITY OF THE
AFOREMENTIONED LINE. INDEED...SURFACE OBS SHOW DEVELOPING CEILINGS
BETWEEN 8000-10,000 FT AND AN ISOLATED CELL HAS RECENTLY POPPED UP
ON RADAR IN CENTRAL ILLINOIS. SHOULD SEE THIS ACTIVITY CONTINUE TO
PERCOLATE THROUGH MID MORNING BEFORE WANING. THINK THERE WILL BE
SOME REDEVELOPMENT THIS AFTERNOON IN THE VICINITY OF THAT VORT CHAIN
WHERE THE MID LEVEL CAPPING AND UPPER LEVEL SUBSIDENCE WILL BE
WEAKEST. COVERAGE WILL LIKELY BE WIDELY SCATTERED AT BEST. WITH
RELATIVELY STAGNANT PATTERN IN PLACE, EXPECT HIGHS TO BE SIMILAR TO
YESTERDAY`S...PERHAPS A DEGREE OR TWO WARMER.
CARNEY
.LONG TERM: (TONIGHT THROUGH MONDAY)
ISSUED AT 355 AM CDT TUE SEP 1 2015
EXPECT ANY THUNDERSTORMS THAT DEVELOP THIS AFTERNOON TO QUICKLY
DISSIPATE EARLY THIS EVENING AS WE LOSE DAYTIME HEATING. WHILE THE
SHEAR AXIS/VORTICITY CHAIN IN THE MID AND UPPER LEVELS WILL STILL BE
IN THE VICINITY OF THE AREA TONIGHT AND WEDNESDAY, IT LOOKS LIKE IT
WILL BE WEAKENING WITH TIME AS WELL AS DIPPING FURTHER SOUTH ACROSS
FAR SOUTHEAST MISSOURI, NORTHEAST ARKANSAS, TENNESSEE, AND KENTUCKY.
I CAN`T TOTALLY RULE OUT AN ISOLATED SHOWER OR THUNDERSTORM
TONIGHT INTO WEDNESAY, BUT THINK PRECIP CHANCES ARE LOW ENOUGH IN
OUR CWFA TO KEEP POPS BELOW MENTIONABLE LEVELS AT THIS TIME.
THE REST OF THE FORECAST AT LEAST THROUGH THE WEEKEND LOOKS PRETTY
UNEVENTFUL. LATE SUMMER-LIKE PATTERN WITH STRONG RIDGING THROUGH
THE DEPTH OF THE TROPOSPHERE SHOULD KEEP THE AREA HOT AND DRY
THROUGH THE WEEKEND. HIGHS LOOK TO BE IN THE LOW TO MID 90S WITH
LOWS GENERALLY IN THE LOW TO MID 70S. DEWPOINT TEMPERATURES SHOULD
STAY IN THE UPPER 60S TO LOW 70S ACROSS THE AREA THOUGH THE PERIOD.
WHILE THIS WILL FEEL WARM AND HUMID, CURRENT THINKING IS THAT HEAT
HEADLINES WILL NOT BE NEEDED. A PATTERN SHIFT WITH SOME COOLER
TEMPERATURES MAY BE IN THE FORECAST NEXT WEEK, BUT GFS AND ECMWF
AREN`T EXACTLY IN GOOD AGREEMENT ON THIS. REGARDLESS...THE SHIFT
(IF IT OCCURS) WILL LIKELY BE TOWARD THE MIDDLE OF THE WEEK; SO HAVE
KEPT WARM TEMPERATURES GOING THROUGH MONDAY.
CARNEY
&&
.AVIATION: (FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 628 AM CDT TUE SEP 1 2015
SO FAR THIS MORNING...VISIBILITIY RESTRICTIONS IN FOG HAS BEEN
FAIRLY LIMITED. HAVE MAINTAINED A MENTION OF BRIEF MVFR VSBYS
FOR THE NEXT HOUR OR SO AT KCOU, KUIN, AND KSUS WHERE OBSERVED
VSBYS AND CLOSE T/TD SPREADS STILL SUGGEST SOME FOG POTENTIAL.
OTHERWISE...WITH LITTLE CHANGE IN AMS AVIATION WEATHER TRENDS
FOR THIS VALID PERIOD SHOULD MIMIC THOSE OF THE PAST 24
HOURS...NAMELY A FEW MID DECK CLOUDS THIS MORNING GIVING WAY TO A
SCATTERED CU FIELD (WITH BASES AOA 4KFT) BY MIDDAY...WITH THESE
CLOUDS DISSIPATING DURING THE EARLY EVENING. MUCH LIKE YESTERDAY
WE WILL BE MONITORING CONVECTIVE TRENDS FOR POSSIBLE INCLUSION IN
TAFS IN NOWCAST UPDATES...HOWEVER BELIEVE THREAT OF CONVECTION AT
ANY ONE LOCATION WILL BE EVEN LESS THAN YESTERDAY, AS SHEAR AXIS
IS A BIT FURTHER S AND E. GIVEN LIMITED FOG THIS MORNING...HAVE
HELD OFF INCLUDING ANY VISIBILITY RESTRICTIONS TONIGHT.
SPECIFICS FOR KSTL: VFR CONDITIONS EXPECTED. A FEW MID CLOUDS
THIS MORNING...THEN SCATTERED CU WITH BASES AOA 4KFT DEVELOPING
DURING THE HEAT OF THE DAY, WITH THESE DIURNALLY DRIVEN CLOUDS
THEN DISSIPATING EARLY THIS EVENING. NO TS MENTIONED IN
FORECAST...AS THE VERY MINIMAL THREAT OF CONVECTION FOR THIS
AFTERNOON WILL BE A BIT FURTHER S AND E THAN YESTERDAY.
TRUETT
&&
.PRELIMINARY POINT TEMPS/POPS:
SAINT LOUIS 91 78 92 78 / 10 10 5 5
QUINCY 90 70 91 70 / 5 5 5 5
COLUMBIA 90 69 91 69 / 10 10 5 5
JEFFERSON CITY 91 69 92 70 / 10 10 5 5
SALEM 89 71 90 70 / 20 10 10 5
FARMINGTON 88 68 91 69 / 20 20 10 5
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
355 AM CDT TUE SEP 1 2015
.SHORT TERM: (THROUGH LATE THIS AFTERNOON)
ISSUED AT 330 AM CDT TUE SEP 1 2015
PRIMARY CONCERN FOR TODAY IS THUNDERSTORM CHANCES THROUGHOUT THE
DAY. SHORT RANGE GUIDANCE CONTINUES TO WANT TO BREAK OUT ISOLATED
TO WIDELY SCATTERED CONVECTION THIS MORNING ALONG A LINE FROM NEAR
WEST PLAINS MISSOURI TO SALEM ILLINOIS. THIS IS IN THE VICINITY OF
A MID-UPPER LEVEL VORTICITY CHAIN STRETCHING UP FROM EAST TEXAS
THROUGH ARKANSAS AND SOUTHEAST MISSOURI INTO INDIANA. RAP SHOWS
SOME WEAK LOW LEVEL WARM ADVECTION AND MOISTURE CONVERGENCE UNDER
THE VORT CHAIN THROUGH MID MORNING AND LATEST IR SAT-PICS SHOW WHAT
LOOKS LIKE ALTO-CUMULUS BREAKING OUT IN THE VICINITY OF THE
AFOREMENTIONED LINE. INDEED...SURFACE OBS SHOW DEVELOPING CEILINGS
BETWEEN 8000-10,000 FT AND AN ISOLATED CELL HAS RECENTLY POPPED UP
ON RADAR IN CENTRAL ILLINOIS. SHOULD SEE THIS ACTIVITY CONTINUE TO
PERCOLATE THROUGH MID MORNING BEFORE WANING. THINK THERE WILL BE
SOME REDEVELOPMENT THIS AFTERNOON IN THE VICINITY OF THAT VORT CHAIN
WHERE THE MID LEVEL CAPPING AND UPPER LEVEL SUBSIDENCE WILL BE
WEAKEST. COVERAGE WILL LIKELY BE WIDELY SCATTERED AT BEST. WITH
RELATIVELY STAGNANT PATTERN IN PLACE, EXPECT HIGHS TO BE SIMILAR TO
YESTERDAY`S...PERHAPS A DEGREE OR TWO WARMER.
CARNEY
.LONG TERM: (TONIGHT THROUGH MONDAY)
ISSUED AT 355 AM CDT TUE SEP 1 2015
EXPECT ANY THUNDERSTORMS THAT DEVELOP THIS AFTERNOON TO QUICKLY
DISSIPATE EARLY THIS EVENING AS WE LOSE DAYTIME HEATING. WHILE THE
SHEAR AXIS/VORTICITY CHAIN IN THE MID AND UPPER LEVELS WILL STILL BE
IN THE VICINITY OF THE AREA TONIGHT AND WEDNESDAY, IT LOOKS LIKE IT
WILL BE WEAKENING WITH TIME AS WELL AS DIPPING FURTHER SOUTH ACROSS
FAR SOUTHEAST MISSOURI, NORTHEAST ARKANSAS, TENNESSEE, AND KENTUCKY.
I CAN`T TOTALLY RULE OUT AN ISOLATED SHOWER OR THUNDERSTORM
TONIGHT INTO WEDNESAY, BUT THINK PRECIP CHANCES ARE LOW ENOUGH IN
OUR CWFA TO KEEP POPS BELOW MENTIONABLE LEVELS AT THIS TIME.
THE REST OF THE FORECAST AT LEAST THROUGH THE WEEKEND LOOKS PRETTY
UNEVENTFUL. LATE SUMMER-LIKE PATTERN WITH STRONG RIDGING THROUGH
THE DEPTH OF THE TROPOSPHERE SHOULD KEEP THE AREA HOT AND DRY
THROUGH THE WEEKEND. HIGHS LOOK TO BE IN THE LOW TO MID 90S WITH
LOWS GENERALLY IN THE LOW TO MID 70S. DEWPOINT TEMPERATURES SHOULD
STAY IN THE UPPER 60S TO LOW 70S ACROSS THE AREA THOUGH THE PERIOD.
WHILE THIS WILL FEEL WARM AND HUMID, CURRENT THINKING IS THAT HEAT
HEADLINES WILL NOT BE NEEDED. A PATTERN SHIFT WITH SOME COOLER
TEMPERATURES MAY BE IN THE FORECAST NEXT WEEK, BUT GFS AND ECMWF
AREN`T EXACTLY IN GOOD AGREEMENT ON THIS. REGARDLESS...THE SHIFT
(IF IT OCCURS) WILL LIKELY BE TOWARD THE MIDDLE OF THE WEEK; SO HAVE
KEPT WARM TEMPERATURES GOING THROUGH MONDAY.
CARNEY
&&
.AVIATION: (FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1105 PM CDT MON AUG 31 2015
WEAK UPPER LOW/SHEAR AXIS WILL BECOME CENTERED OVER INDIANA BY
MIDDAY TUESDAY. SUSPECT THAT WILL KEEP MOST OF THE TSRA DEELOPMENT
EAST OF THE TERMINALS. WHILE A ISOLATED STORM POSSIBLE, NO REASON
TO PUT IT IN THE FORECAST. PATCHY FOG OVERNIGHT, BASICALLY A
PERSISTENCE FORECAST.
SPECIFICS FOR KSTL: VFR DRY FORECAST CONTINUES. HIGH PRESSURE
BEGINS BUILDING THUS THE THE ISOLATED AFTERNOON THUNDERSTORMS WILL
BECOME EVEN MORE ISOLATED. WOULD NOT BE SURPRISED TO SEE SOME
MORNING FOG/HAZE START APPEARING THE NEXT COUPLE OF DAYS.
JPK
&&
.PRELIMINARY POINT TEMPS/POPS:
SAINT LOUIS 91 78 92 78 / 10 10 5 5
QUINCY 90 70 91 70 / 5 5 5 5
COLUMBIA 90 69 91 69 / 10 10 5 5
JEFFERSON CITY 91 69 92 70 / 10 10 5 5
SALEM 89 71 90 70 / 20 10 10 5
FARMINGTON 88 68 91 69 / 20 20 10 5
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
331 AM CDT TUE SEP 1 2015
.SHORT TERM: (THROUGH LATE THIS AFTERNOON)
ISSUED AT 330 AM CDT TUE SEP 1 2015
PRIMARY CONCERN FOR TODAY IS THUNDERSTORM CHANCES THROUGHOUT THE
DAY. SHORT RANGE GUIDANCE CONTINUES TO WANT TO BREAK OUT ISOLATED
TO WIDELY SCATTERED CONVECTION THIS MORNING ALONG A LINE FROM NEAR
WEST PLAINS MISSOURI TO SALEM ILLINOIS. THIS IS IN THE VICINITY OF
A MID-UPPER LEVEL VORTICITY CHAIN STRETCHING UP FROM EAST TEXAS
THROUGH ARKANSAS AND SOUTHEAST MISSOURI INTO INDIANA. RAP SHOWS
SOME WEAK LOW LEVEL WARM ADVECTION AND MOISTURE CONVERGENCE UNDER
THE VORT CHAIN THROUGH MID MORNING AND LATEST IR SAT-PICS SHOW WHAT
LOOKS LIKE ALTO-CUMULUS BREAKING OUT IN THE VICINITY OF THE
AFOREMENTIONED LINE. INDEED...SURFACE OBS SHOW DEVELOPING CEILINGS
BETWEEN 8000-10,000 FT AND AN ISOLATED CELL HAS RECENTLY POPPED UP
ON RADAR IN CENTRAL ILLINOIS. SHOULD SEE THIS ACTIVITY CONTINUE TO
PERCOLATE THROUGH MID MORNING BEFORE WANING. THINK THERE WILL BE
SOME REDEVELOPMENT THIS AFTERNOON IN THE VICINITY OF THAT VORT CHAIN
WHERE THE MID LEVEL CAPPING AND UPPER LEVEL SUBSIDENCE WILL BE
WEAKEST. COVERAGE WILL LIKELY BE WIDELY SCATTERED AT BEST. WITH
RELATIVELY STAGNANT PATTERN IN PLACE, EXPECT HIGHS TO BE SIMILAR TO
YESTERDAY`S...PERHAPS A DEGREE OR TWO WARMER.
CARNEY
.LONG TERM: (TUESDAY THROUGH NEXT MONDAY)
ISSUED AT 304 PM CDT MON AUG 31 2015
(TUESDAY THROUGH THURSDAY)
PLAN TO GO WITH A DRY FORECAST FROM TUESDAY AFTERNOON THROUGH
THURSDAY AS FORCING FOR THUNDERSTORMS LOOKS WEAK AS UPPER LOW MOVES
EAST AND UPPER RIDGE AXIS BUILDS OVER THE AREA WHICH SHOULD SUPPRESS
THUNDERSTORM DEVELOPMENT. DON`T EXPECT MUCH CHANCE IN THE WARM AND
HUMID CONDITIONS. BASED HIGHS ON MIXING DOWN 850MB TEMPERATURES
WHICH ARE CLOSE TO +20C.
(FRIDAY THROUGH MONDAY)
FORECAST STILL LOOKS ON TRACK FOR MAINLY DRY WEATHER EARLY ON FOR
THE HOLIDAY WEEKEND AS THE UPPER LEVEL RIDGE AXIS MOVES OVER THE
AREA WHICH WILL SUPPRESS THUNDERSTORMS ACTIVITY ON FRIDAY AND
SATURDAY. THIS RIDGE AXIS WILL BEGIN TO BREAK DOWN BY SUNDAY...SO
WILL KEEP THE SLIGHT CHANCE OF THUNDERSTORMS OVER NORTHEAST MISSOURI
ON SUNDAY. WILL GO WITH A WIDER CHANCE OF THUNDERSTORMS ON LABOR
DAY AS BOTH THE GFS AND ECMWF SHOW THE RIDGE AXIS MOVING SOUTH OF
THE AREA AT THE SAME TIME A COLD FRONT ENTERS THE AREA FROM THE
NORTH. STILL WENT ABOVE NORMAL THROUGH THE HOLIDAY WEEKEND AS WE
WILL STAY IN THE SAME WARM AND HUMID AIRMASS UNTIL THE COLD FRONT
MOVES THROUGH.
BRITT
&&
.AVIATION: (FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1105 PM CDT MON AUG 31 2015
WEAK UPPER LOW/SHEAR AXIS WILL BECOME CENTERED OVER INDIANA BY
MIDDAY TUESDAY. SUSPECT THAT WILL KEEP MOST OF THE TSRA DEELOPMENT
EAST OF THE TERMINALS. WHILE A ISOLATED STORM POSSIBLE, NO REASON
TO PUT IT IN THE FORECAST. PATCHY FOG OVERNIGHT, BASICALLY A
PERSISTENCE FORECAST.
SPECIFICS FOR KSTL: VFR DRY FORECAST CONTINUES. HIGH PRESSURE
BEGINS BUILDING THUS THE THE ISOLATED AFTERNOON THUNDERSTORMS WILL
BECOME EVEN MORE ISOLATED. WOULD NOT BE SURPRISED TO SEE SOME
MORNING FOG/HAZE START APPEARING THE NEXT COUPLE OF DAYS.
JPK
&&
.PRELIMINARY POINT TEMPS/POPS:
SAINT LOUIS 91 78 92 78 / 10 10 5 5
QUINCY 90 70 91 70 / 5 5 5 5
COLUMBIA 90 69 91 69 / 10 10 5 5
JEFFERSON CITY 91 69 92 70 / 10 10 5 5
SALEM 89 71 90 70 / 20 10 10 5
FARMINGTON 88 68 91 69 / 20 20 10 5
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1117 PM CDT MON AUG 31 2015
.UPDATE:
ISSUED AT 858 PM CDT MON AUG 31 2015
THE ISOLATED SHOWERS/STORMS ACROSS PARTS OF SOUTHEAST AND EAST
CENTRAL MO AND SOUTHWEST IL HAVE DISSIPATED THIS EVENING DUE TO THE
LOSS OF DAYTIME HEATING WITH MUCH OF THE CONVECTIVE CLOUD DEBRIS
ALSO DISSIPATING AS WELL. MAY HAVE SOME NOCTURNAL DEVELOPMENT OF
CONVECTION LATE TONIGHT/EARLY TUESDAY MORNING ACROSS PARTS OF
SOUTHWEST IL...OVER THE EASTERN PORTION OF THE FORECAST AREA JUST
WEST OF AN UPPER LEVEL LOW. THE LATEST HRRR MODEL RUN DOES
GENERATE CONVECTION IN THIS AREA...ALTHOUGH THE LATEST NAM MODEL
RUN DOES NOT HAVE ANY QPF IN THIS AREA LATE TONIGHT AS THE
PREVIOUS RUN OF THIS MODEL DID. WILL JUST KEEP THE SLIGHT CHANCE
POPS OVER THE EASTERN PORTION OF THE FORECAST AREA BEGINNING AT
11Z TUESDAY. A MILD MUGGY NIGHT CAN BE EXPECTED WITH SOUTH-
SOUTHEASTERLY SURFACE WINDS AND HIGH SURFACE DEW POINTS. THERE MAY
BE SOME PATCHY LIGHT FOG/HAZE. THE LOWS TONIGHT SHOULD BE SIMILAR
TO THE PREVIOUS NIGHT AND ABOUT 5 TO 10 DEGREES ABOVE NORMAL FOR
EARLY SEPTEMBER.
GKS
&&
.SHORT TERM: (THROUGH LATE TONIGHT)
ISSUED AT 304 PM CDT MON AUG 31 2015
THUNDERSTORMS THAT PRODUCED HEAVY RAINFALL OVER THE EASTERN CWA THIS
MORNING DISSIPATED WITH THE LOSS OF THE WEAK LOW LEVEL MOISTURE
CONVERGENCE ON THE WEST SIDE OF THE UPPER LEVEL LOW CURRENT CENTERED
OVER INDIANA. MORE RECENTLY...ATMOSPHERE HAS BECOME VERY UNSTABLE
WITH MLCAPES OF 2000-3000 J/KG WITH LITTLE CIN. SHEAR AXIS HAS
MOVED DOWN INTO SOUTHERN MISSOURI...SO THINK BEST CHANCE FOR
THUNDERSTORMS WILL BE OVER THE EASTERN OZARKS...PARTICULARLY SINCE
THAT IS TRADITIONALLY WHERE OROGRAPHIC LIFT HAS HELPED GENERATE LATE
AFTERNOON/EARLY EVENING THUNDERSTORMS IN THE PAST. WOULD EXPECT ANY
CONVECTION TO DIMINISH WITH LOSS OF DAYTIME HEATING.
ADDITIONAL THUNDERSTORMS WILL BE POSSIBLE ONCE AGAIN LATE TONIGHT
OVER THE EASTERN CWA AS BOTH THE NAM AND GFS ARE POINTING TOWARD TO
SOME WEAK 925-850MB MOISTURE CONVERGENCE DEVELOPING ONCE AGAIN ON
THE WEST SIDE OF THE UPPER LEVEL LOW. WILL GO WITH A SLIGHT CHANCE
OF THUNDERSTORMS LATE TONIGHT THROUGH TOMORROW MORNING.
BRITT
.LONG TERM: (TUESDAY THROUGH NEXT MONDAY)
ISSUED AT 304 PM CDT MON AUG 31 2015
(TUESDAY THROUGH THURSDAY)
PLAN TO GO WITH A DRY FORECAST FROM TUESDAY AFTERNOON THROUGH
THURSDAY AS FORCING FOR THUNDERSTORMS LOOKS WEAK AS UPPER LOW MOVES
EAST AND UPPER RIDGE AXIS BUILDS OVER THE AREA WHICH SHOULD SUPPRESS
THUNDERSTORM DEVELOPMENT. DON`T EXPECT MUCH CHANCE IN THE WARM AND
HUMID CONDITIONS. BASED HIGHS ON MIXING DOWN 850MB TEMPERATURES
WHICH ARE CLOSE TO +20C.
(FRIDAY THROUGH MONDAY)
FORECAST STILL LOOKS ON TRACK FOR MAINLY DRY WEATHER EARLY ON FOR
THE HOLIDAY WEEKEND AS THE UPPER LEVEL RIDGE AXIS MOVES OVER THE
AREA WHICH WILL SUPPRESS THUNDERSTORMS ACTIVITY ON FRIDAY AND
SATURDAY. THIS RIDGE AXIS WILL BEGIN TO BREAK DOWN BY SUNDAY...SO
WILL KEEP THE SLIGHT CHANCE OF THUNDERSTORMS OVER NORTHEAST MISSOURI
ON SUNDAY. WILL GO WITH A WIDER CHANCE OF THUNDERSTORMS ON LABOR
DAY AS BOTH THE GFS AND ECMWF SHOW THE RIDGE AXIS MOVING SOUTH OF
THE AREA AT THE SAME TIME A COLD FRONT ENTERS THE AREA FROM THE
NORTH. STILL WENT ABOVE NORMAL THROUGH THE HOLIDAY WEEKEND AS WE
WILL STAY IN THE SAME WARM AND HUMID AIRMASS UNTIL THE COLD FRONT
MOVES THROUGH.
BRITT
&&
.AVIATION: (FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1105 PM CDT MON AUG 31 2015
WEAK UPPER LOW/SHEAR AXIS WILL BECOME CENTERED OVER INDIANA BY
MIDDAY TUESDAY. SUSPECT THAT WILL KEEP MOST OF THE TSRA DEELOPMENT
EAST OF THE TERMINALS. WHILE A ISOLATED STORM POSSIBLE, NO REASON
TO PUT IT IN THE FORECAST. PATCHY FOG OVERNIGHT, BASICALLY A
PERSISTENCE FORECAST.
SPECIFICS FOR KSTL: VFR DRY FORECAST CONTINUES. HIGH PRESSURE
BEGINS BUILDING THUS THE THE ISOLATED AFTERNOON THUNDERSTORMS WILL
BECOME EVEN MORE ISOLATED. WOULD NOT BE SURPRISED TO SEE SOME
MORNING FOG/HAZE START APPEARING THE NEXT COUPLE OF DAYS.
JPK
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
606 PM CDT WED SEP 2 2015
.SYNOPSIS...
ISSUED AT 322 PM CDT WED SEP 2 2015
H5 ANALYSIS THIS MORNING HAD LOW PRESSURE OVER WEST
CENTRAL PORTIONS OF BRITISH COLUMBIA WITH A TROUGH EXTENDING TO THE
SOUTHWEST INTO THE NERN PACIFIC. SOUTH OF THE LOW 50 TO 60 METER HT
FALLS WERE NOTED OVER OREGON AND WASHINGTION STATE WITH A 50 KT JET
STREAK COLLOCATED WITH THE HT FALLS. EAST OF THE LOW...BROAD WEST
SOUTHWESTERLY FLOW EXTENDED ACROSS THE NRN TIER OF STATES AND SRN
CANADA. SOUTH OF THE LOW AND JET STREAK...TWO SHORTWAVES WERE
NOTED...ONE NEAR LAS VEGAS AND A SECOND OFF THE COAST OF SRN
CALIFORNIA. AT THE SURFACE...A TROUGH OF LOW PRESSURE EXTENDED FROM
NORTH CENTRAL NEBRASKA INTO SWRN KS THIS AFTERNOON. WINDS BEHIND
THIS FEATURE WERE FROM THE WEST AT UNDER 10 MPH...WHILE EAST OF THIS
FEATURE...WINDS WERE FROM THE SOUTH AT AROUND 10 MPH. TEMPERATURES
AS OF 3 PM CDT RANGED FROM 95 AT ONEILL...TO 100 AT VALENTINE.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 322 PM CDT WED SEP 2 2015
WEAK UPPER HEIGHT RISES ONGOING ACROSS THE AREA AS CENTRAL PLAINS
RIDGE BUILDS IN RESPONSE TO DEEPENING TROUGH ACROSS THE PAC NW.
THE SFC REFLECTION TO THIS IS A WEAK SFC TROUGH ACROSS THE MIDDLE
OF THE WESTERN HALF OF NEB...THOUGH WINDS ARE LIGHT MOST
LOCATIONS. MOST NOTABLE DIFFERENCE ACROSS THE ARE ARE DEW POINT
TEMPS WHICH HAVE DROPPED INTO THE UPPER 40S FROM VTN TO OGA...WITH
MID 60S HANGING ON FROM BBW TO ONL AT THIS HOUR. LOW LEVEL
MOISTURE NOT MIXING OUT AS FAR EAST AS THE NAM SUGGESTED...AND FAR
FROM WHAT THE GFS HAD WHICH IS A KNOWN ISSUE WITH THE GFS. DRY
LINE WILL RETREAT WWD AFTER SUNSET UNDER MAINLY CLEAR SKIES.
OPERATIONAL HRRR AND RAP DEVELOPING A SMALL AREA OF CONVECTIVE
PRECIP LATE THIS AFTERNOON AS WEAK FORCING ALOFT OVERLAYS THE DRY
LINE BOUNDARY. SHORT TERM FCST SOUNDINGS FROM THE HRRR AND RAP
SHOW PRONOUNCED INVERTED V PROFILE WITH VERY LITTLE CAPE ABOVE THE
LFC. HAVE NOT INCLUDED MENTION OF PRECIP NOR QPF THIS EVENING WITH
THE IDEA THAT DRY AIR ENTRAINMENT WILL INHIBIT THE POTENTIAL FOR
DEEP...MOIST CONVECTION SUFFICIENT FOR PRECIP.
AS FLOW BECOMES MORE MERIDIONAL WITH THE DEEPENING UPPER TROUGH IN
THE NW...NEXT PV ANOMALY AND ASSOCIATED PUSH OF MID AND UPPER LEVEL
MOISTURE WILL ROTATE NWD OUT OF THE SWRN UNITED STATES. THIS SHOULD
ALLOW FOR MORE SHOWER AND THUNDERSTORM DEVELOPMENT OVER THE HIGHER
TERRAIN FURTHER WEST WHICH WILL MOVE INTO THE WESTERN PORTIONS OF
THE AREA BY LATE AFTERNOON THURSDAY. SOME LARGE SCALE HEIGHT FALLS
ASSOCIATED WITH THIS FEATURE WILL ALLOW FOR SLIGHT COOLING OF THE
UPPER LEVELS AND WHEN PAIRED WITH SOMEWHAT DEEPER MOISTURE WITH
SERLY SFC WINDS...WILL BE SUFFICIENT FOR POSITIVE CAPE ABOVE THE
LOWER LFC BY LATE IN THE DAY. WEAK SHEAR REMAINS HOWEVER SO ALTHOUGH
BETTER CHANCES EXIST FOR THUNDERSTORMS...LARGE SCALE ORGANIZATION
DOES NOT LOOK FAVORABLE THROUGH 00Z FRI. THE ADDED MID AND UPPER
LEVEL MOISTURE AND ASSOCIATED CLOUDS WITH CONVECTION IN SWRLY
FLOW...WHICH HAS ORIGINS IN THE TROPICS ACCORDING TO ANALYSIS OF
320K MIXING RATIO...WILL ALLOW SLIGHTLY COOLER MAX TEMPS FOR
THURSDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 322 PM CDT WED SEP 2 2015
THURSDAY NIGHT THROUGH SATURDAY NIGHT...IN THE MID RANGE...THE MAIN
FORECASTING CHALLENGES ARE PRECIPITATION CHANCES THURSDAY NIGHT...AND
AGAIN ON FRIDAY NIGHT INTO SATURDAY. FOR THURSDAY
NIGHT...THUNDERSTORMS WILL BE ONGOING ACROSS SWRN NEBR AND NERN
COLORADO AT THE BEGINNING OF THE PERIOD. THIS ACTIVITY WILL MOVE
NORTHEAST INTO THE NIGHTTIME HOURS THANKS TO DECENT MID LEVEL
WAA...WHICH TRACKS FROM SOUTHWESTERN INTO NORTH CENTRAL NEBRASKA. IN
ADDITION...THE NOSE OF A H85 JET STREAK WILL TRACK FROM SOUTH
CENTRAL INTO EASTERN NEBRASKA OVERNIGHT...ADDING ADDTL SUPPORT FOR
PRECIPITATION. AS FOR CHANCES...DECIDED TO KEEP THESE ON THE LOWER
SIDE OF THE ENVELOP AS TIME SECTIONS ARE INDICATIVE OF A DECENT DRY
LAYER BELOW 10000 FT AGL WHICH WILL LIMIT COVERAGE AS WELL AS QPF/S.
ON FRIDAY...STORMS WILL LINGER INTO THE MORNING HOURS ACROSS NERN
PORTIONS OF THE FORECAST AREA. BY AFTERNOON...TRANQUIL WEATHER CONDS
ARE EXPECTED AS THE FORECAST AREA IS IN BETWEEN SYSTEMS. SLIGHTLY
DRIER AIR WILL PUSH INTO THE NORTHWESTERN CWA FRIDAY WITH A DRYLINE
EXTENDING FROM NORTH CENTRAL INTO SWRN NEBRASKA. UPPER LEVEL FORCING
WILL HOLD OFF UNTIL FRIDAY AFTERNOON...SO MOST LOCATIONS WILL SEE A
DRY FCST ON FRIDAY. PCPN CHANCES WILL BEGIN TO INCREASE FRIDAY
EVENING AS A STRONG UPPER LEVEL DISTURBANCE LIFTS ACROSS EASTERN
COLORADO...APPG WESTERN NEBRASKA FRIDAY EVENING. THE BEFORE
MENTIONED DRYLINE WILL RETREAT WEST DURING THE EVENING HRS. HOW FAR
WEST THIS RETREATS AND THE AMOUNT OF DEEP LAYER MOISTURE AVAILABLE
FRIDAY NIGHT IS SOMEWHAT IN DOUBT ATTM. THE GFS IS MUCH DRIER IN THE
WEST COMPARED TO THE NAM SOLN. IN FACT...LAYER PW/S ARE RUNNING
AROUND A HALF AN INCH DRIER IN THE GFS COMPARED TO THE NAM SOLN. NO
SURPRISE...THE GFS IS DRY WITH ITS QPF FIELD FRIDAY NIGHT AND THE
NAM DEVELOPS CONVECTION INVOF THE DRYLINE. INHERITED FCST HAD A
MENTION OF PCPN FRIDAY NIGHT...AND WITH THE GFS BEING TOO DRY IN ITS
LOWER LEVELS UPON INITIALIZATION THIS MORNING...LEANED TOWARD THE
WETTER NAM SOLN WHICH SEEMED TO DO BETTER WITH THE MOISTURE FIELD.
THAT BEING SAID...PRECIPITATION CHANCES IN THE 20 TO 30 PERCENT
RANGE SEEM PLAUSIBLE FOR NOW. THE THREAT FOR PCPN WILL LINGER INTO
SATURDAY IN THE NORTH DURING THE MORNING HOURS...THEN WITH POSSIBLE
DEVELOPMENT OVER EASTERN AND CENTRAL NEBRASKA SATURDAY AFTERNOON. AS
FOR DEVELOPMENT SATURDAY AFTERNOON...ONCE AGAIN...THE GFS SEEMS TOO
DRY WITH ITS MOISTURE FIELD AND CONTINUE TO LEAN TOWARD THE WETTER
NAM SOLN WHICH INITIATES A LINE OF CONVECTION ACROSS THE CENTRAL AND
EASTERN CWA SAT AFTN. DEEP LAYER WIND SHEAR FINALLY REACHES 30 TO 40
KTS SAT AFTN...SO WOULDN/T BE SURPRISED IF A STRONG TO SEVERE STORM
DEVELOPS SAT AFTN/EVE.
SUNDAY THROUGH WEDNESDAY...IN THE EXTENDED...A STRONG UPPER LEVEL
LOW WILL TRACK ACROSS THE NORTHERN ROCKIES INTO SOUTH CENTRAL CANADA
SUNDAY INTO MONDAY. ON SUNDAY...A PREFRONTAL TROUGH WILL PUSH
THROUGH MOST OF THE FORECAST AREA...FORCING LOW LEVEL MOISTURE INTO
CENTRAL AND EASTERN NEBRASKA. FOR THE BULK OF THE FORECAST
AREA...SUNDAY AND SUNDAY NIGHT WILL BE DRY...HOWEVER...LOCATIONS IN
THE FAR NORTHEASTERN CWA WILL SEE A SLIGHT CHANCE FOR RAIN SUNDAY
AFTERNOON/NIGHT. ON SUNDAY NIGHT...A STRONG COLD FRONT WILL PASS
THROUGH THE FORECAST AREA...AND FOR THE MOST PART...WILL BE A DRY
FROPA WITH THE EXCEPTION OF THE FAR EASTERN CWA WHERE SOME LIMITED
MOISTURE WILL REMAIN IN PLACE. THE FRONT WILL THEN STALL ACROSS FAR
SRN NEBRASKA MONDAY...THEN LIFT NORTH MONDAY NIGHT INTO TUESDAY AS A
SECOND UPPER LEVEL WAVE DEVELOPS OVER THE NRN ROCKIES. WITH THE
FRONTAL BOUNDARY DRAPED ACROSS THE FORECAST AREA TUESDAY INTO
WEDNESDAY...WENT AHEAD AND LEFT IN A MENTION OF PCPN. TEMPERATURES
BEHIND THE FRONT MONDAY...TUESDAY AND WEDNESDAY WILL GENERALLY BE IN
THE 70S TO LOWER 80S WHICH IS RIGHT AT SEASONAL FOR EARLY
SEPTEMBER.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 603 PM CDT WED SEP 2 2015
WIND TONIGHT AND THURSDAY MORNING WILL BE 140-180 AT 3-8KT IN
CENTRAL AND WESTERN NEBRASKA BUT...BY MID AFTERNOON...THE WIND
WILL BE 160-190 AT 10-14KT. CEILING AND VISIBILITY WILL BE
UNLIMITED TONIGHT THROUGH THURSDAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CLB
SHORT TERM...JWS
LONG TERM...CLB
AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1236 PM CDT TUE SEP 1 2015
.SYNOPSIS...
ISSUED AT 352 AM CDT TUE SEP 1 2015
AT 08Z...WEAK SURFACE LOW PRESSURE WAS CENTERED NEAR MCK. A SMALL
AREA OF SHOWERS EXTENDED ACROSS PORTIONS OF SWRN NEBR AS NARROW BAND
OF THUNDERSTORMS EXTENDED SOUTH INTO EXTREME NW KS. TEMPERATURES
RANGED FROM THE UPPER 60S TO LOWER 70S ACROSS EASTERN PORTIONS OF
NCTRL NEBR TO THE LOWER 60S ERN PNHDL. SKIES WERE MOSTLY CLOUDY
ACROSS MOST OF WESTERN AND NCTRL NEBR.
&&
.UPDATE...
ISSUED AT 1235 PM CDT TUE SEP 1 2015
HAVE UPDATED THE FORECAST TO REFLECT SHOWERS AND ISOLATED
THUNDERSTORMS EXITING PARTS OF NC NEB OVER THE NEXT FEW HOURS AS
WELL AS ADDING THE POTENTIAL FOR ISOLATED THUNDERSTORMS NEAR THE
SFC TROUGH AXIS IN THE ERN PANHANDLE LATE AFTERNOON AND EARLY
EVENING...HOWEVER CONFIDENCE IN THAT IS NOT HIGH. RAP CROSS
SECTIONS SUGGEST A WEAK CIRCULATION ASSOCIATED WITH THE TROUGH AND
WEAK CAPE ABOVE ACCORDING TO BUFR SOUNDINGS. WATER VAPOR IMAGERY
INDICATES A DECENT PV ANOMALY AND ASSOCIATED LIGHTNING MOVING
NEWD FROM ERN UTAH INTO NWRN COLORADO. THEREFORE SOME POTENTIAL
FOR DEVELOPMENT DESPITE VERY DRY LOW LAYERS AND WEAK SHEAR NEAR
THE SFC TROUGH. OTHERWISE REMAINDER OF FCST LEFT AS IS FOR NOW.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM CDT TUE SEP 1 2015
THE NAM AND HRRR IN GOOD AGREEMENT WITH A DISTURBANCE CURRENTLY ON
EXTREME SWRN NEBR. THIS APPEARS TO HAVE AN MCV EXITING DUNDY COUNTY.
THIS DISTURBANCE WILL LIFT NORTHEAST TO AREAS EAST OF ANW THROUGH BBW
BY 18Z. THIS WILL BE SUPPORTIVE OF SLIGHT CHC POPS FOR -TSRA TODAY.
THE ATMOSPHERE WILL BE FAIRLY SATURATED FROM H7 TO H3...AND MUCH
DRIER H7 TO THE SURFACE. THEREFORE THE SHOWERS WILL HAVE A DIFFICULT
TIME REACHING THE SURFACE IN SOME AREAS AND COVERAGE WILL BE
LIMITED. MOSTLY CLOUDY SKIES IN THE WEST EARLY THIS MORNING TO
BECOME MOSTLY SUNNY BY MID MORNING WHILE THE EAST IS FORECAST TO BE
PARTLY TO MOSTLY CLOUDY THROUGH AT LEAST MIDDAY...THEN CLEARING BY
LATE AFTERNOON. THE WEAK FRONTAL BOUNDARY THIS MORNING WILL WASH
OUT BY AFTERNOON WITH A LIGHT SOUTH WIND IN THE AFTN. H85 TEMPS
NEAR 29C ERN PNHDLE SUPPORTIVE OF LOWER 90S ACROSS THE WEST. AREAS
EAST OF ANW THROUGH BBW TO REACH THE UPPER 80S.
FOR TONIGHT...KEPT A SLIGHT CHC FOR -TSRA ACROSS THE EAST THIS
EVENING...ALTHOUGH THE NAM AND GFS HAVE TRENDED FAVORED AREAS OF ANY
SHOWERS TO THE EAST OF THE FA. THE RAP13 AND HRRR STILL INDICATE
LATE AFTN REDEVELOPMENT IN THE EAST WHICH MAY LINGER THIS EVENING.
SKIES TO BECOME MOSTLY CLEAR ALL AREAS OVERNIGHT. LOWS TONIGHT FROM
NEAR 60 WESTERN SANDHILLS TO AROUND 65 EAST.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 352 AM CDT TUE SEP 1 2015
A LONG WAVE UPPER LEVEL TROUGH WILL DIG SOUTH FROM THE GULF OF
ALASKA INTO THE PACIFIC NORTHWEST THROUGH THE END OF THE WORKWEEK.
DURING THE LABOR DAY WEEKEND...A CUT OFF UPPER LEVEL LOW PRESSURE
SYSTEM WILL DEVELOP WITHIN LONG WAVE TROUGH ACROSS THE ACROSS THE
PACIFIC NORTHWEST. THIS UPPER LOW WILL THEN MOVE SLOWLY EAST
NORTHEAST TOWARD SOUTHERN CANADA AND THE NORTHERN PLAINS EARLY NEXT
WEEK. AHEAD OF THIS FEATURE...UPPER LEVEL RIDGING WILL EXPAND
NORTHWARD INTO OUR REGION FROM THE SOUTHERN PLAINS THROUGH THE END
OF THE WORKWEEK...WITH VERY WARM TO HOT HIGH TEMPERATURES IN THE 90S
TO PERSIST THROUGH AT LEAST FRIDAY. LITTLE CHANCE FOR RAIN IS
EXPECTED THROUGH THURSDAY WITH VERY WARM MID LEVEL TEMPERATURES
/CAPPING INVERSION/ TO OVERSPREAD THE REGION.
RAIN CHANCES WILL BEGIN TO INCREASE A BIT BY FRIDAY AND CONTINUE
THROUGH LABOR DAY WEEKEND...AS BETTER MID AND UPPER LEVEL FORCING
OVERSPREADS THE AREA IN ASSOCIATION WITH THE UPPER LEVEL LOW ACROSS
THE PACIFIC NORTHWEST. OVERALL THE FORCING LOOKS TO REMAIN FAIRLY
WEAK...AND WILL KEEP RAIN CHANCES IN THE 20 TO 30 PERCENT RANGE
THROUGH THE WEEKEND. MODELS TONIGHT ARE IN SOMEWHAT BETTER AGREEMENT
REGARDING THE COLD FRONT THAT WILL BE INCHING TOWARD THE REGION THIS
WEEKEND. THE GFS IS SLOWING THE FRONT DOWN AND NOW BRINGS THE FRONT
INTO NORTHERN NEBRASKA SUNDAY AFTERNOON...A FULL DAY LATER THAN IT
WAS INDICATING YESTERDAY. THE ECMWF IS STILL THE SLOWER
SOLUTION...AND IS STICKING TO A MONDAY MORNING FRONTAL PASSAGE. THE
TREND IS FOR A SLOWER ARRIVAL OF THE COLD FRONT...AND WILL WARM HIGH
TEMPERATURES A FEW DEGREES FOR SATURDAY TO NEAR 90...AND FOR SUNDAY
WILL WARM HIGHS SEVERAL DEGREES INTO THE MID 80S.
A FAIRLY TIGHT PRESSURE GRADIENT WILL DEVELOP FRIDAY INTO SATURDAY
AS PRESSURE LOWERS ALONG THE FRONT RANGE OF THE ROCKIES. THIS WILL
RESULT IN GUSTY SOUTH WINDS BOTH FRIDAY AND SATURDAY. WOULD NOT BE
SURPRISED TO SEE 30 MPH GUSTS BOTH DAYS...ESPECIALLY FOR AREAS EAST
OF A LINE FROM VALENTINE TO NORTH PLATTE. SUNDAY HAS THE POTENTIAL
TO HAVE BREEZY SOUTH WINDS ALSO...AS THE FRONT WILL LIKELY STILL BE
OFF TO THE NORTHWEST OF THE AREA. BY LABOR DAY WINDS SHOULD SHIFT TO
THE NORTH-NORTHWEST AS THE FRONT CROSSES THE AREA...WITH HIGH
TEMPERATURES SETTLING BACK INTO THE UPPER 70S AND LOWER 80S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1235 PM CDT TUE SEP 1 2015
VFR CONDITIONS THROUGH THE PERIOD. SHOWERS EXITING EAST OF THE
KVTN TAF AREA CURRENTLY...AND HAVE LEFT IN SCT MID LEVEL CLOUDS
THAT MAY BE ASSOCIATED WITH ISOLD TSRA THAT ARE POSSIBLE LATE
AFTERNOON AND EVENING. OTHERWISE A QUIET PATTERN THROUGH MID DAY
TMRW.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JWS
SYNOPSIS...ROBERG
SHORT TERM...ROBERG
LONG TERM...TAYLOR
AVIATION...JWS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
651 AM CDT TUE SEP 1 2015
.SYNOPSIS...
ISSUED AT 352 AM CDT TUE SEP 1 2015
AT 08Z...WEAK SURFACE LOW PRESSURE WAS CENTERED NEAR MCK. A SMALL
AREA OF SHOWERS EXTENDED ACROSS PORTIONS OF SWRN NEBR AS NARROW BAND
OF THUNDERSTORMS EXTENDED SOUTH INTO EXTREME NW KS. TEMPERATURES
RANGED FROM THE UPPER 60S TO LOWER 70S ACROSS EASTERN PORTIONS OF
NCTRL NEBR TO THE LOWER 60S ERN PNHDL. SKIES WERE MOSTLY CLOUDY
ACROSS MOST OF WESTERN AND NCTRL NEBR.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM CDT TUE SEP 1 2015
THE NAM AND HRRR IN GOOD AGREEMENT WITH A DISTURBANCE CURRENTLY ON
EXTREME SWRN NEBR. THIS APPEARS TO HAVE AN MCV EXITING DUNDY COUNTY.
THIS DISTURBANCE WILL LIFT NORTHEAST TO AREAS EAST OF ANW THROUGH BBW
BY 18Z. THIS WILL BE SUPPORTIVE OF SLIGHT CHC POPS FOR -TSRA TODAY.
THE ATMOSPHERE WILL BE FAIRLY SATURATED FROM H7 TO H3...AND MUCH
DRIER H7 TO THE SURFACE. THEREFORE THE SHOWERS WILL HAVE A DIFFICULT
TIME REACHING THE SURFACE IN SOME AREAS AND COVERAGE WILL BE
LIMITED. MOSTLY CLOUDY SKIES IN THE WEST EARLY THIS MORNING TO
BECOME MOSTLY SUNNY BY MID MORNING WHILE THE EAST IS FORECAST TO BE
PARTLY TO MOSTLY CLOUDY THROUGH AT LEAST MIDDAY...THEN CLEARING BY
LATE AFTERNOON. THE WEAK FRONTAL BOUNDARY THIS MORNING WILL WASH
OUT BY AFTERNOON WITH A LIGHT SOUTH WIND IN THE AFTN. H85 TEMPS
NEAR 29C ERN PNHDLE SUPPORTIVE OF LOWER 90S ACROSS THE WEST. AREAS
EAST OF ANW THROUGH BBW TO REACH THE UPPER 80S.
FOR TONIGHT...KEPT A SLIGHT CHC FOR -TSRA ACROSS THE EAST THIS
EVENING...ALTHOUGH THE NAM AND GFS HAVE TRENDED FAVORED AREAS OF ANY
SHOWERS TO THE EAST OF THE FA. THE RAP13 AND HRRR STILL INDICATE
LATE AFTN REDEVELOPMENT IN THE EAST WHICH MAY LINGER THIS EVENING.
SKIES TO BECOME MOSTLY CLEAR ALL AREAS OVERNIGHT. LOWS TONIGHT FROM
NEAR 60 WESTERN SANDHILLS TO AROUND 65 EAST.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 352 AM CDT TUE SEP 1 2015
A LONG WAVE UPPER LEVEL TROUGH WILL DIG SOUTH FROM THE GULF OF
ALASKA INTO THE PACIFIC NORTHWEST THROUGH THE END OF THE WORKWEEK.
DURING THE LABOR DAY WEEKEND...A CUT OFF UPPER LEVEL LOW PRESSURE
SYSTEM WILL DEVELOP WITHIN LONG WAVE TROUGH ACROSS THE ACROSS THE
PACIFIC NORTHWEST. THIS UPPER LOW WILL THEN MOVE SLOWLY EAST
NORTHEAST TOWARD SOUTHERN CANADA AND THE NORTHERN PLAINS EARLY NEXT
WEEK. AHEAD OF THIS FEATURE...UPPER LEVEL RIDGING WILL EXPAND
NORTHWARD INTO OUR REGION FROM THE SOUTHERN PLAINS THROUGH THE END
OF THE WORKWEEK...WITH VERY WARM TO HOT HIGH TEMPERATURES IN THE 90S
TO PERSIST THROUGH AT LEAST FRIDAY. LITTLE CHANCE FOR RAIN IS
EXPECTED THROUGH THURSDAY WITH VERY WARM MID LEVEL TEMPERATURES
/CAPPING INVERSION/ TO OVERSPREAD THE REGION.
RAIN CHANCES WILL BEGIN TO INCREASE A BIT BY FRIDAY AND CONTINUE
THROUGH LABOR DAY WEEKEND...AS BETTER MID AND UPPER LEVEL FORCING
OVERSPREADS THE AREA IN ASSOCIATION WITH THE UPPER LEVEL LOW ACROSS
THE PACIFIC NORTHWEST. OVERALL THE FORCING LOOKS TO REMAIN FAIRLY
WEAK...AND WILL KEEP RAIN CHANCES IN THE 20 TO 30 PERCENT RANGE
THROUGH THE WEEKEND. MODELS TONIGHT ARE IN SOMEWHAT BETTER AGREEMENT
REGARDING THE COLD FRONT THAT WILL BE INCHING TOWARD THE REGION THIS
WEEKEND. THE GFS IS SLOWING THE FRONT DOWN AND NOW BRINGS THE FRONT
INTO NORTHERN NEBRASKA SUNDAY AFTERNOON...A FULL DAY LATER THAN IT
WAS INDICATING YESTERDAY. THE ECMWF IS STILL THE SLOWER
SOLUTION...AND IS STICKING TO A MONDAY MORNING FRONTAL PASSAGE. THE
TREND IS FOR A SLOWER ARRIVAL OF THE COLD FRONT...AND WILL WARM HIGH
TEMPERATURES A FEW DEGREES FOR SATURDAY TO NEAR 90...AND FOR SUNDAY
WILL WARM HIGHS SEVERAL DEGREES INTO THE MID 80S.
A FAIRLY TIGHT PRESSURE GRADIENT WILL DEVELOP FRIDAY INTO SATURDAY
AS PRESSURE LOWERS ALONG THE FRONT RANGE OF THE ROCKIES. THIS WILL
RESULT IN GUSTY SOUTH WINDS BOTH FRIDAY AND SATURDAY. WOULD NOT BE
SURPRISED TO SEE 30 MPH GUSTS BOTH DAYS...ESPECIALLY FOR AREAS EAST
OF A LINE FROM VALENTINE TO NORTH PLATTE. SUNDAY HAS THE POTENTIAL
TO HAVE BREEZY SOUTH WINDS ALSO...AS THE FRONT WILL LIKELY STILL BE
OFF TO THE NORTHWEST OF THE AREA. BY LABOR DAY WINDS SHOULD SHIFT TO
THE NORTH-NORTHWEST AS THE FRONT CROSSES THE AREA...WITH HIGH
TEMPERATURES SETTLING BACK INTO THE UPPER 70S AND LOWER 80S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 650 AM CDT TUE SEP 1 2015
RAIN SHOWERS HAVE JUST EXITED THE KLBF TERMINAL AND ARE EXPECTED
TO REMAIN SOUTHEAST OF THE KVTN TERMINAL THIS MORNING. SKIES
SCT080 BKN120 TO BECOME SCT200 BY 18Z. LIGHT AND VARIABLE WINDS
THIS MORNING TO BECOME 15010KT THIS AFTERNOON.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ROBERG
SHORT TERM...ROBERG
LONG TERM...TAYLOR
AVIATION...ROBERG
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
353 AM CDT TUE SEP 1 2015
.SYNOPSIS...
ISSUED AT 352 AM CDT TUE SEP 1 2015
AT 08Z...WEAK SURFACE LOW PRESSURE WAS CENTERED NEAR MCK. A SMALL
AREA OF SHOWERS EXTENDED ACROSS PORTIONS OF SWRN NEBR AS NARROW BAND
OF THUNDERSTORMS EXTENDED SOUTH INTO EXTREME NW KS. TEMPERATURES
RANGED FROM THE UPPER 60S TO LOWER 70S ACROSS EASTERN PORTIONS OF
NCTRL NEBR TO THE LOWER 60S ERN PNHDL. SKIES WERE MOSTLY CLOUDY
ACROSS MOST OF WESTERN AND NCTRL NEBR.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM CDT TUE SEP 1 2015
THE NAM AND HRRR IN GOOD AGREEMENT WITH A DISTURBANCE CURRENTLY ON
EXTREME SWRN NEBR. THIS APPEARS TO HAVE AN MCV EXITING DUNDY COUNTY.
THIS DISTURBANCE WILL LIFT NORTHEAST TO AREAS EAST OF ANW THROUGH BBW
BY 18Z. THIS WILL BE SUPPORTIVE OF SLIGHT CHC POPS FOR -TSRA TODAY.
THE ATMOSPHERE WILL BE FAIRLY SATURATED FROM H7 TO H3...AND MUCH
DRIER H7 TO THE SURFACE. THEREFORE THE SHOWERS WILL HAVE A DIFFICULT
TIME REACHING THE SURFACE IN SOME AREAS AND COVERAGE WILL BE
LIMITED. MOSTLY CLOUDY SKIES IN THE WEST EARLY THIS MORNING TO
BECOME MOSTLY SUNNY BY MID MORNING WHILE THE EAST IS FORECAST TO BE
PARTLY TO MOSTLY CLOUDY THROUGH AT LEAST MIDDAY...THEN CLEARING BY
LATE AFTERNOON. THE WEAK FRONTAL BOUNDARY THIS MORNING WILL WASH
OUT BY AFTERNOON WITH A LIGHT SOUTH WIND IN THE AFTN. H85 TEMPS
NEAR 29C ERN PNHDLE SUPPORTIVE OF LOWER 90S ACROSS THE WEST. AREAS
EAST OF ANW THROUGH BBW TO REACH THE UPPER 80S.
FOR TONIGHT...KEPT A SLIGHT CHC FOR -TSRA ACROSS THE EAST THIS
EVENING...ALTHOUGH THE NAM AND GFS HAVE TRENDED FAVORED AREAS OF ANY
SHOWERS TO THE EAST OF THE FA. THE RAP13 AND HRRR STILL INDICATE
LATE AFTN REDEVELOPMENT IN THE EAST WHICH MAY LINGER THIS EVENING.
SKIES TO BECOME MOSTLY CLEAR ALL AREAS OVERNIGHT. LOWS TONIGHT FROM
NEAR 60 WESTERN SANDHILLS TO AROUND 65 EAST.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 352 AM CDT TUE SEP 1 2015
A LONG WAVE UPPER LEVEL TROUGH WILL DIG SOUTH FROM THE GULF OF
ALASKA INTO THE PACIFIC NORTHWEST THROUGH THE END OF THE WORKWEEK.
DURING THE LABOR DAY WEEKEND...A CUT OFF UPPER LEVEL LOW PRESSURE
SYSTEM WILL DEVELOP WITHIN LONG WAVE TROUGH ACROSS THE ACROSS THE
PACIFIC NORTHWEST. THIS UPPER LOW WILL THEN MOVE SLOWLY EAST
NORTHEAST TOWARD SOUTHERN CANADA AND THE NORTHERN PLAINS EARLY NEXT
WEEK. AHEAD OF THIS FEATURE...UPPER LEVEL RIDGING WILL EXPAND
NORTHWARD INTO OUR REGION FROM THE SOUTHERN PLAINS THROUGH THE END
OF THE WORKWEEK...WITH VERY WARM TO HOT HIGH TEMPERATURES IN THE 90S
TO PERSIST THROUGH AT LEAST FRIDAY. LITTLE CHANCE FOR RAIN IS
EXPECTED THROUGH THURSDAY WITH VERY WARM MID LEVEL TEMPERATURES
/CAPPING INVERSION/ TO OVERSPREAD THE REGION.
RAIN CHANCES WILL BEGIN TO INCREASE A BIT BY FRIDAY AND CONTINUE
THROUGH LABOR DAY WEEKEND...AS BETTER MID AND UPPER LEVEL FORCING
OVERSPREADS THE AREA IN ASSOCIATION WITH THE UPPER LEVEL LOW ACROSS
THE PACIFIC NORTHWEST. OVERALL THE FORCING LOOKS TO REMAIN FAIRLY
WEAK...AND WILL KEEP RAIN CHANCES IN THE 20 TO 30 PERCENT RANGE
THROUGH THE WEEKEND. MODELS TONIGHT ARE IN SOMEWHAT BETTER AGREEMENT
REGARDING THE COLD FRONT THAT WILL BE INCHING TOWARD THE REGION THIS
WEEKEND. THE GFS IS SLOWING THE FRONT DOWN AND NOW BRINGS THE FRONT
INTO NORTHERN NEBRASKA SUNDAY AFTERNOON...A FULL DAY LATER THAN IT
WAS INDICATING YESTERDAY. THE ECMWF IS STILL THE SLOWER
SOLUTION...AND IS STICKING TO A MONDAY MORNING FRONTAL PASSAGE. THE
TREND IS FOR A SLOWER ARRIVAL OF THE COLD FRONT...AND WILL WARM HIGH
TEMPERATURES A FEW DEGREES FOR SATURDAY TO NEAR 90...AND FOR SUNDAY
WILL WARM HIGHS SEVERAL DEGREES INTO THE MID 80S.
A FAIRLY TIGHT PRESSURE GRADIENT WILL DEVELOP FRIDAY INTO SATURDAY
AS PRESSURE LOWERS ALONG THE FRONT RANGE OF THE ROCKIES. THIS WILL
RESULT IN GUSTY SOUTH WINDS BOTH FRIDAY AND SATURDAY. WOULD NOT BE
SURPRISED TO SEE 30 MPH GUSTS BOTH DAYS...ESPECIALLY FOR AREAS EAST
OF A LINE FROM VALENTINE TO NORTH PLATTE. SUNDAY HAS THE POTENTIAL
TO HAVE BREEZY SOUTH WINDS ALSO...AS THE FRONT WILL LIKELY STILL BE
OFF TO THE NORTHWEST OF THE AREA. BY LABOR DAY WINDS SHOULD SHIFT TO
THE NORTH-NORTHWEST AS THE FRONT CROSSES THE AREA...WITH HIGH
TEMPERATURES SETTLING BACK INTO THE UPPER 70S AND LOWER 80S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1134 PM CDT MON AUG 31 2015
A LINE OF THUNDERSTORMS ARE MAKING THEIR WAY THROUGH SOUTHWEST
NEBRASKA AND SHOULD REACH LBF AFTER 08Z AND VTN AFTER 10Z. THERE
IS SOME DOUBT THAT THEY WILL MAKE IT TO VTN SO WE ARE INCLUDING
ONLY VCTS 12-14Z THERE. FOR LBF...OUR CONFIDENCE IS HIGHER THAT
THEY WILL GET THERE NEAR 08Z AND WE HAVE INCLUDED A TEMPORARY
CONDITION OF 3SM TSRA 10-12Z. THE STORMS ARE EXPECTED TO REACH
ANW...ONL AND BBW BETWEEN 14Z AND 16Z. HEAVY RAIN IS EXPECTED WITH
THE STORMS BUT HAIL...IF ANY WILL BE SMALL.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ROBERG
SHORT TERM...ROBERG
LONG TERM...TAYLOR
AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
758 AM PDT TUE SEP 1 2015
.SYNOPSIS...A TROUGH OF LOW PRESSURE IN THE NORTHWESTERN PART OF THE
COUNTRY WILL BRING A DRY SOUTHWESTERLY FLOW TO THE AREA THROUGH THE
WEEK. TEMPERATURES WILL BE NEAR NORMAL THROUGH MIDWEEK BEFORE
FALLING BELOW NORMAL FOR THE LATTER HALF OF THE WORKWEEK AS THE
TROUGH DEEPENS. PERIODS OF HIGH CLOUDS CAN BE EXPECTED AT TIMES BUT
OTHERWISE DRY CONDITIONS ARE EXPECTED.
&&
.UPDATE...FAIRLY QUIET WEATHER TODAY WITH BREEZY CONDITIONS BEING
THE PRIMARY SENSIBLE WEATHER. UPDATED THE WIND GRIDS TO ACCOUNT FOR
THE LATEST TRENDS AND GUIDANCE WHICH RESULTS IN BUMPING UP SPEEDS
EARLIER ACROSS THE AREA TODAY. WILL ALSO BE MONITORING
SHOWER/THUNDERSTORM POTENTIAL OVER NORTHEAST MOHAVE COUNTY.
&&
.AVIATION...FOR MCCARRAN...CHALLENGING WIND FORECAST FOR MCCARRAN
TODAY. SOUTHEAST WINDS HAVE INCREASED EARLIER THAN PREVIOUSLY
EXPECTED. THE HRRR SEEMS TO BE MOST IN LINE WITH THE CURRENT
CONDITIONS...WHICH KEEPS SPEEDS UP AT 10-15 KTS WITH GUSTS 15-25 KTS
THROUGH THIS EVENING. MULTIPLE CHANGES FROM SOUTHEAST TO SOUTHWEST
WINDS WILL BE POSSIBLE TODAY. OTHERWISE...JUST SOME PASSING HIGH
CLOUDS EXPECTED WITH DISTANT THUNDERSTORMS AGAIN POSSIBLE IN THE
PEACH SPRINGS CORRIDOR.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...GENERALLY SOUTHERLY WINDS EXPECTED WITH SPEEDS IN THE
10-15KT RANGE DURING THE AFTERNOONS WITH GUSTS TO 25KTS. AREAS OF
SMOKE LIKELY AGAIN IN THE OWENS VALLEY AND NEAR BISHOP. ISOLATED
THUNDERSTORMS ALSO POSSIBLE ACROSS NORTHWEST ARIZONA NEAR MT
TRUMBULL IN MOHAVE COUNTY.
&&
.PREV DISCUSSION...
220 AM PDT TUE SEP 1 2015
.SHORT TERM...THROUGH THURSDAY.
SEPTEMBER HAS ARRIVED WHICH USUALLY MARKS THE BEGINNING OF A TREND
TOWARDS COOLER WEATHER AND A SLOW DOWNTURN OF THE MONSOON. SO FAR
LOOKS LIKE THINGS ARE ON TRACK AS A STRONG PACIFIC TROUGH WILL BE
INFLUENCING OUR WEATHER THIS WEEK BRINGING A TREND TOWARDS COOLER
TEMPERATURES WHILE SHUNTING MOST OF THE MONSOON FLOW TO OUR EAST.
TEMPERATURES TODAY WILL REMAIN SLIGHTLY ABOVE NORMAL WITH INCREASING
SCATTERED HIGH CLOUDS AT TIMES IN RESPONSE TO A DISTURBANCE OFF THE
PACIFIC COAST. MONSOON MOISTURE WAS CONFINED TO FAR EASTERN MOHAVE
COUNTY MONDAY AND MOISTURE WILL BE EVEN MORE SCARCE TODAY. I`VE
RETAINED SLIGHT CHANCES FOR THUNDERSTORMS FOR THE HIGHER TERRAIN OF
EXTREME EASTERN MOHAVE COUNTY BUT COVERAGE WILL BE QUITE SPARSE.
ON WEDNESDAY...AFOREMENTIONED PACIFIC TROUGH WILL BEGIN TO CARVE
ITSELF OUT ACROSS THE PACIFIC NORTHWEST STATES WHICH WILL INDUCE A
STRENGTHENING PRESSURE GRADIENT ACROSS THE GREAT BASIN. THIS MEANS
WIND WILL BECOME STRONGER AND GUSTIER WEDNESDAY. WINDS WILL BE
STRONGEST ACROSS THE SOUTHERN GREAT BASIN AND INYO COUNTY MOUNTAINS
WHERE WIND GUSTS MAY APPROACH 40 MPH IN ISOLATED POCKETS. SIMILAR
CONDITIONS ARE EXPECTED THURSDAY. AS THE TROUGH INTENSIFIES TO OUR
NORTH...HEIGHTS WILL GRADUALLY FALL RESULTING IN COOLER TEMPERATURES
THURSDAY ONWARD...ANYWHERE BETWEEN 4 AND 8 DEGREES BELOW NORMAL.
.LONG TERM...THURSDAY THROUGH SUNDAY.
THE PERIOD STARTS OUT WITH A CLOSED LOW OVER WESTERN WASHINGTON WITH
AN ASSOCIATED TROUGH EXTENDING ALL THE WAY DOWN THE WEST COAST. THE
CLOSED LOW WILL TRACK SLOWLY EAST ACROSS THE PACIFIC NORTHWEST INTO
THE NORTHERN ROCKIES THROUGH SUNDAY WITH A TROUGH REMAINING ROUGHLY
ALONG THE WEST COAST. THIS WILL RESULT IN A PERSISTENT SOUTHWEST
FLOW OVER OUR FORECAST AREA WHICH LOOKS TO BE MAINLY DRY AND STABLE
WITH AFTERNOON SOUTH/SOUTHWEST BREEZES. WE WILL STILL HAVE TO KEEP
AN EYE ON MOISTURE FROM A CURRENTLY UN-NAMED TROPICAL SYSTEM WHICH
IS FORECAST TO GET PULLED UP INTO ARIZONA. THIS MOISTURE COULD CLIP
EASTERN MOHAVE COUNTY FRIDAY BUT I STILL KEPT NO MENTION OF
THUNDERSTORMS FOR NOW. THE MODELS HAVE BEEN CONSISTENTLY BRINGING
THE BULK OF THAT MOISTURE INTO CENTRAL/EASTERN ARIZONA AND NEW
MEXICO. THE MODELS REALLY DIVERGE BY MONDAY. THE ECMWF HAS BASICALLY
A DRY WEST/SOUTHWEST FLOW OVER OUR AREA WHILE THE GFS HAS MORE OF A
MONSOON LIKE PATTERN WITH HIGH PRESSURE EAST AND A CLOSED LOW OFF
THE CALIFORNIA COAST. THIS GFS SOLUTION WOULD BRING MOISTURE UP INTO
THE AREA RESULTING IN THUNDERSTORM CHANCES FOR AT LEAST MOHAVE
COUNTY BY MONDAY AFTERNOON. I CHOSE TO MAKE NO CHANGES AND KEPT A
DRY FORECAST GOING AS UNCERTAINTY IS HIGH DUE TO SIGNIFICANT MODEL
DIFFERENCES. TEMPERATURES THROUGH THE LONG TERM ARE EXPECTED TO BE
JUST A LITTLE BELOW NORMAL.
&&
.FIRE WEATHER...DRY FUELS AND LOW MINIMUM RELATIVE HUMIDITY VALUES
ACROSS NYE AND ESMERALDA COUNTIES COLLOCATED WITH AFTERNOON WINDS OF
20-25 MPH WITH GUSTS OF 35 TO 40 MPH MAKE FIRE WEATHER A CONCERN
BOTH WEDNESDAY AND THURSDAY. BORDERLINE RED FLAG CONDITIONS MAY
BLEED WESTWARD INTO PARTS OF INYO COUNTY AS WELL. A FIRE WEATHER
WATCH HAS BEEN POSTED FOR NYE AND ESMERALDA COUNTIES FOR WEDNESDAY
AND THURSDAY WHERE THE HIGHEST CONFIDENCE EXISTS ON RED FLAG
CONDITIONS MATERIALIZING.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTER ACTIVATION WILL NOT BE
NECESSARY. HOWEVER...SPOTTERS ARE ENCOURAGED TO REPORT ANY
SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
UPDATE/AVIATION...WOLCOTT
SHORT TERM...OUTLER
LONG TERM....HARRISON
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1044 PM EDT WED SEP 2 2015
.SYNOPSIS...
A WEAK TROUGH WILL CROSS THE REGION TONIGHT AND THURSDAY PRODUCING A
FEW ISOLATED SHOWERS AND THUNDERSTORMS...BUT THE VAST MAJORITY OF
THE AREA WILL REMAIN DRY. HIGH PRESSURE RETURNS FOR FRIDAY WITH A
RETURN TO SUNSHINE AND VERY WARM TEMPERATURES WHICH WILL LAST
THROUGH THE ENTIRE LABOR DAY WEEKEND.
&&
.NEAR TERM /THROUGH THURSDAY/...
THROUGH LATE THIS EVENING...RADAR SHOWS JUST A FEW ISOLATED
SHOWERS IN OUR CWA...WITH THE VAST MAJORITY OF THE AREA DRY. THIS
TREND SHOULD CONTINUE THROUGH MOST OF THE NIGHT WITH ISOLATED
CONVECTION WHICH WILL LEAVE THE VAST MAJORITY OF THE REGION DRY.
A WEAK LOW LEVEL TROUGH WILL DROP SOUTH OUT OF ONTARIO LATE
TONIGHT. AS THIS FEATURE CROSSES THE WARM WATERS OF LAKE
ONTARIO...THE ADDED BOOST OF LAKE MOISTURE AND INSTABILITY MAY BE
ENOUGH TO PRODUCE A FEW WIDELY SCATTERED SHOWERS OR THUNDERSTORMS
ALONG THE SOUTH SHORE OF LAKE ONTARIO LATE TONIGHT AND THURSDAY
MORNING. THE 12Z GUIDANCE HAS BACKED OFF FROM THIS SOLUTION
SOMEWHAT BUT SEVERAL RUNS OF THE HRRR STILL DEVELOPS SOME SHOWERS.
PAST EXPERIENCE HAS SHOWN THAT EVEN WEAK BOUNDARIES CAN PRODUCE
SCATTERED CONVECTION OVER THE WARM LAKES DURING THE OVERNIGHT AND
MORNING HOURS.
OTHERWISE EXPECT MORE FOG TO DEVELOP TONIGHT AND THURSDAY MORNING
WITH THE ABUNDANT LOW LEVEL MOISTURE AND LONGER SEPTEMBER NIGHTS.
MOST OF THE FOG WILL BE ON THE LIGHT SIDE...BUT MORE DENSE FOG WILL
FORM ONCE AGAIN IN THE SOUTHERN TIER RIVER VALLEYS. MAY ALSO SEE
ADVECTION FOG DEVELOP OVER AND NORTHEAST OF LAKES ERIE AND
ONTARIO...POSSIBLY AFFECTING THE BUFFALO AREA AND JEFFERSON COUNTY
SHORELINE. TEMPERATURES WILL REMAIN WARM WITH LOWS IN THE UPPER 60S
ON THE LAKE PLAINS AND LOWER 60S IN THE COOLEST SOUTHERN TIER
VALLEYS AND TUG HILL REGION.
BY THURSDAY AFTERNOON THE WEAK TROUGH WILL BE PUSHING SOUTH INTO THE
SOUTHERN TIER AND NORTHERN PA. MODERATE AFTERNOON INSTABILITY
COMBINED WITH WEAK CONVERGENCE ALONG THE TROUGH AND UPSLOPE FLOW MAY
PRODUCE A FEW WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE
HIGHER TERRAIN SOUTH OF THE NYS THRUWAY. GIVEN WARM MID LEVEL TEMPS
AND WEAK FORCING COVERAGE OF THIS ACTIVITY SHOULD REMAIN SPARSE. THE
LAKE PLAINS FROM THE LAKE ERIE SHORE TO THE NIAGARA FRONTIER AND
ROCHESTER SHOULD SEE INCREASING AMOUNTS OF SUNSHINE DURING THE
AFTERNOON AS NORTHWEST FLOW SPREADS STABLE LAKE SHADOWS INLAND.
IT WILL BE ANOTHER WARM DAY WITH HIGHS IN THE MID 80S ACROSS LOWER
ELEVATIONS AND LOWER 80S ON THE HILLS. THE DEVELOPING NORTHWEST FLOW
WILL KEEP THE LAKESHORES A LITTLE COOLER. DEWPOINTS WILL REMAIN IN
THE 65-70 DEGREE RANGE MAKING FOR ANOTHER HUMID DAY.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
FORECAST LOOKS GOOD IN THIS PERIOD PER LATEST GUIDANCE. PREVIOUS
DISCUSSION...
WARM AND DRY LATE SUMMER WEATHER WILL CONTINUE. A WEAK UPPER LOW
STALLED UNDERNEATH A LONGWAVE RIDGE IS FORECAST TO STALL ACROSS
MICHIGAN WHILE RIDGING STRENGTHENS ACROSS NEW ENGLAND. MEANWHILE...A
SURFACE HIGH WILL DROP SOUTHWARD FROM CANADA AND ADVECT SLIGHTLY
COOLER AND DRIER AIR INTO THE REGION. TEMPERATURES WILL REMAIN ABOVE
NORMAL WITH HIGHS AVERAGING IN THE LOWER 80S ON FRIDAY.
DEW POINTS WILL ALSO DROP INTO THE LOWER 60S TO UPPER 50S WHICH WILL
MAKE IT FEEL LESS HUMID. THIS WILL RESULT IN COOLER OVERNIGHT LOWS
WHICH SHOULD DROP TO NEAR THESE DEW POINT VALUES ON THURSDAY AND
FRIDAY NIGHTS. FOG SHOULD FORM EACH NIGHT...BUT THE DRIER AIR MASS
SHOULD RESULT IN LESS WIDESPREAD FOG IN THE MORE TYPICAL VALLEY
LOCATIONS AND MAYBE ALONG THE LAKE PLAINS SOUTH OF LAKE ONTARIO.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
THE HOLIDAY WEEKEND WILL BE WARM AND SUNNY AS THE AXIS OF THE UPPER
LEVEL RIDGE SHIFTS ACROSS THE GREAT LAKES WITH STRONG SURFACE HIGH
PRESSURE DOMINATING AT THE SURFACE. HIGHS WILL RUN IN THE MID 80S
SATURDAY AND SUNDAY WITH THE WARMEST TEMPERATURES OF THE PERIOD
FALLING ON MONDAY AS THE CENTER OF THE HIGH SHIFTS TO THE MID-
ATLANTIC STATES AND SOUTHWESTERLY FLOW RETURNS TO THE LOWER GREAT
LAKES...IN TURN ADVECTING WARMER AIR OUT OF THE OHIO VALLEY AND
GENERATING DOWNSLOPING THAT WILL PUSH TEMPERATURES ON LABOR DAY INTO
THE MID TO UPPER 80S ACROSS THE GENESEE VALLEY AND NORTH OF THE
FINGER LAKES WITH MID 80S ELSEWHERE. LOWS THROUGH THE PERIOD WILL
CONTINUE TO RUN IN THE 60S.
12Z GFS/ECMWF/GGEM GUIDANCE ARE IN EXCELLENT AGREEMENT THROUGH
MONDAY AND ALTHOUGH THIS AGREEMENT BREAKS DOWN A BIT TOWARD MID-WEEK
THE INDIVIDUAL SOLUTIONS ARE STILL FAIRLY CLOSE. CONSENSUS HAS A
WEAK COLD FRONT APPROACHING MONDAY NIGHT WITH THIS LIKELY TO DROP
ACROSS OR INTO OUR REGION ON TUESDAY BEFORE STALLING OUT TUESDAY
NIGHT. THEN A SHORTWAVE WILL LIFT THIS BOUNDARY BACK TOWARD THE
REGION WITH AN INCREASING CHANCE FOR THUNDERSTORMS ON WEDNESDAY.
DESPITE THE COLD FRONT...TEMPERATURES SHOULD REMAIN ABOVE NORMAL
THROUGH MID-WEEK.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
FOR THE 03Z TAF CYCLE...FOG HAS BEEN SLOWER TO DEVELOP THAN LAST
NIGHT...WITH THE 00Z BUFFALO SOUNDING SHOWING A GENERALLY DRIER
AIR MASS. MOSTLY CLEAR SKIES SHOULD ALLOW FOG TO DEVELOP...WITH
THE MOST WIDESPREAD FOG ACROSS THE SOUTHERN TIER MOST LIKELY TO
IMPACT JHW. FOG/STRATUS SHOULD ALSO FORM AS A TROUGH DROPS ACROSS
THE REGION WITH IFR CONDITIONS ALSO LIKELY LATE TONIGHT AT
ART...WITH A LESSER CHANCE FOR LOW VSBY AT BUF/IAG/ROC.
ON THURSDAY SCATTERED SHOWERS AND THUNDERSTORMS WILL
DEVELOP...WITH MOST OF THESE LIKELY TO MISS TAF LOCATIONS. ANY
IMPACT WOULD BE BRIEF. CONDITIONS MAY START OFF IFR OR LOWER IN
SOME SPOTS...BUT THESE SHOULD IMPROVE AS LOW MOISTURE EVENTUALLY
MIXES OUT.
OUTLOOK...
FRIDAY THROUGH MONDAY...VFR. LOCALIZED IFR IN OVERNIGHT/EARLY
MORNING FOG.
&&
.MARINE...
A WEAK TROUGH WILL CROSS THE LOWER LAKES ON THURSDAY. IN THE WAKE OF
THIS TROUGH NORTHEAST WINDS WILL INCREASE TO AROUND 15 KNOTS
THURSDAY NIGHT AND FRIDAY ON BOTH LAKES. THIS WILL PRODUCE SOME
CHOPPY WAVE ACTION...BUT CONDITIONS ARE EXPECTED TO REMAIN BELOW
SMALL CRAFT ADVISORY CRITERIA.
HIGH PRESSURE WILL THEN BUILD ALONG THE EAST COAST OVER THE LABOR
DAY HOLIDAY WEEKEND AND PROVIDE LIGHT WINDS AND FLAT WAVE ACTION
SATURDAY THROUGH MONDAY.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...HITCHCOCK
NEAR TERM...APFFEL/HITCHCOCK
SHORT TERM...APFFEL/FRANKLIN
LONG TERM...APFFEL
AVIATION...APFFEL
MARINE...APFFEL/HITCHCOCK
AREA FORECAST DISCUSSION
NWS BUFFALO NY
928 PM EDT WED SEP 2 2015
.SYNOPSIS...
A WEAK TROUGH WILL CROSS THE REGION TONIGHT AND THURSDAY PRODUCING A
FEW ISOLATED SHOWERS AND THUNDERSTORMS...BUT THE VAST MAJORITY OF
THE AREA WILL REMAIN DRY. HIGH PRESSURE RETURNS FOR FRIDAY WITH A
RETURN TO SUNSHINE AND VERY WARM TEMPERATURES WHICH WILL LAST
THROUGH THE ENTIRE LABOR DAY WEEKEND.
&&
.NEAR TERM /THROUGH THURSDAY/...
THROUGH EARLY EVENING...RADAR SHOWS SCATTERED SHOWERS AND
THUNDERSTORMS NORTH OF LAKE ONTARIO...BUT NONE REMAINING IN OUR
CWA. THIS WILL LEAVE MAINLY DRY CONDITIONS THROUGH THE REMAINDER
OF THE EVENING AND MOST OF THE NIGHT. LATE TONIGHT A WEAK LOW
LEVEL TROUGH WILL DROP SOUTH OUT OF ONTARIO. AS THIS FEATURE
CROSSES THE WARM WATERS OF LAKE ONTARIO...THE ADDED BOOST OF LAKE
MOISTURE AND INSTABILITY MAY BE ENOUGH TO PRODUCE A FEW WIDELY
SCATTERED SHOWERS OR THUNDERSTORMS ALONG THE SOUTH SHORE OF LAKE
ONTARIO LATE TONIGHT AND THURSDAY MORNING. THE 12Z GUIDANCE HAS
BACKED OFF FROM THIS SOLUTION SOMEWHAT BUT THE HRRR DOES HAVE IT.
PAST EXPERIENCE HAS SHOWN THAT EVEN WEAK BOUNDARIES CAN PRODUCE
SCATTERED CONVECTION OVER THE WARM LAKES DURING THE OVERNIGHT AND
MORNING HOURS.
OTHERWISE EXPECT MORE FOG TO DEVELOP TONIGHT AND THURSDAY MORNING
WITH THE ABUNDANT LOW LEVEL MOISTURE AND LONGER SEPTEMBER NIGHTS.
MOST OF THE FOG WILL BE ON THE LIGHT SIDE...BUT MORE DENSE FOG WILL
FORM ONCE AGAIN IN THE SOUTHERN TIER RIVER VALLEYS. MAY ALSO SEE
ADVECTION FOG DEVELOP OVER AND NORTHEAST OF LAKES ERIE AND
ONTARIO...POSSIBLY AFFECTING THE BUFFALO AREA AND JEFFERSON COUNTY
SHORELINE. TEMPERATURES WILL REMAIN WARM WITH LOWS IN THE UPPER 60S
ON THE LAKE PLAINS AND LOWER 60S IN THE COOLEST SOUTHERN TIER
VALLEYS AND TUG HILL REGION.
BY THURSDAY AFTERNOON THE WEAK TROUGH WILL BE PUSHING SOUTH INTO THE
SOUTHERN TIER AND NORTHERN PA. MODERATE AFTERNOON INSTABILITY
COMBINED WITH WEAK CONVERGENCE ALONG THE TROUGH AND UPSLOPE FLOW MAY
PRODUCE A FEW WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE
HIGHER TERRAIN SOUTH OF THE NYS THRUWAY. GIVEN WARM MID LEVEL TEMPS
AND WEAK FORCING COVERAGE OF THIS ACTIVITY SHOULD REMAIN SPARSE. THE
LAKE PLAINS FROM THE LAKE ERIE SHORE TO THE NIAGARA FRONTIER AND
ROCHESTER SHOULD SEE INCREASING AMOUNTS OF SUNSHINE DURING THE
AFTERNOON AS NORTHWEST FLOW SPREADS STABLE LAKE SHADOWS INLAND.
IT WILL BE ANOTHER WARM DAY WITH HIGHS IN THE MID 80S ACROSS LOWER
ELEVATIONS AND LOWER 80S ON THE HILLS. THE DEVELOPING NORTHWEST FLOW
WILL KEEP THE LAKESHORES A LITTLE COOLER. DEWPOINTS WILL REMAIN IN
THE 65-70 DEGREE RANGE MAKING FOR ANOTHER HUMID DAY.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
FORECAST LOOKS GOOD IN THIS PERIOD PER LATEST GUIDANCE. PREVIOUS
DISCUSSION...
WARM AND DRY LATE SUMMER WEATHER WILL CONTINUE. A WEAK UPPER LOW
STALLED UNDERNEATH A LONGWAVE RIDGE IS FORECAST TO STALL ACROSS
MICHIGAN WHILE RIDGING STRENGTHENS ACROSS NEW ENGLAND. MEANWHILE...A
SURFACE HIGH WILL DROP SOUTHWARD FROM CANADA AND ADVECT SLIGHTLY
COOLER AND DRIER AIR INTO THE REGION. TEMPERATURES WILL REMAIN ABOVE
NORMAL WITH HIGHS AVERAGING IN THE LOWER 80S ON FRIDAY.
DEW POINTS WILL ALSO DROP INTO THE LOWER 60S TO UPPER 50S WHICH WILL
MAKE IT FEEL LESS HUMID. THIS WILL RESULT IN COOLER OVERNIGHT LOWS
WHICH SHOULD DROP TO NEAR THESE DEW POINT VALUES ON THURSDAY AND
FRIDAY NIGHTS. FOG SHOULD FORM EACH NIGHT...BUT THE DRIER AIR MASS
SHOULD RESULT IN LESS WIDESPREAD FOG IN THE MORE TYPICAL VALLEY
LOCATIONS AND MAYBE ALONG THE LAKE PLAINS SOUTH OF LAKE ONTARIO.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
THE HOLIDAY WEEKEND WILL BE WARM AND SUNNY AS THE AXIS OF THE UPPER
LEVEL RIDGE SHIFTS ACROSS THE GREAT LAKES WITH STRONG SURFACE HIGH
PRESSURE DOMINATING AT THE SURFACE. HIGHS WILL RUN IN THE MID 80S
SATURDAY AND SUNDAY WITH THE WARMEST TEMPERATURES OF THE PERIOD
FALLING ON MONDAY AS THE CENTER OF THE HIGH SHIFTS TO THE MID-
ATLANTIC STATES AND SOUTHWESTERLY FLOW RETURNS TO THE LOWER GREAT
LAKES...IN TURN ADVECTING WARMER AIR OUT OF THE OHIO VALLEY AND
GENERATING DOWNSLOPING THAT WILL PUSH TEMPERATURES ON LABOR DAY INTO
THE MID TO UPPER 80S ACROSS THE GENESEE VALLEY AND NORTH OF THE
FINGER LAKES WITH MID 80S ELSEWHERE. LOWS THROUGH THE PERIOD WILL
CONTINUE TO RUN IN THE 60S.
12Z GFS/ECMWF/GGEM GUIDANCE ARE IN EXCELLENT AGREEMENT THROUGH
MONDAY AND ALTHOUGH THIS AGREEMENT BREAKS DOWN A BIT TOWARD MID-WEEK
THE INDIVIDUAL SOLUTIONS ARE STILL FAIRLY CLOSE. CONSENSUS HAS A
WEAK COLD FRONT APPROACHING MONDAY NIGHT WITH THIS LIKELY TO DROP
ACROSS OR INTO OUR REGION ON TUESDAY BEFORE STALLING OUT TUESDAY
NIGHT. THEN A SHORTWAVE WILL LIFT THIS BOUNDARY BACK TOWARD THE
REGION WITH AN INCREASING CHANCE FOR THUNDERSTORMS ON WEDNESDAY.
DESPITE THE COLD FRONT...TEMPERATURES SHOULD REMAIN ABOVE NORMAL
THROUGH MID-WEEK.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
FOR THE 00Z TAF CYCLE...DIURNALLY DRIVEN CUMULUS HAVE SCATTERED
OUT LEAVING VFR CONDITIONS IN MOST LOCATIONS. SOME FOG AND LOW
STRATUS MAY FORM AGAIN THIS EVENING OVER LAKE ERIE AND ONTARIO...
BUT WITH LIGHT FLOW THIS SHOULD PRIMARILY REMAIN OVER AND ALONG
THE LAKESHORES WITH LITTLE IMPACT ON THE TERMINALS. BY LATE
EVENING PATCHY FOG/BR WILL BEGIN TO FORM ACROSS LAND AREAS WITH
MVFR/IFR VSBY DEVELOPING. FOG WILL BECOME MOST WIDESPREAD ACROSS
THE SOUTHERN TIER RIVER VALLEYS OVERNIGHT WITH LIFR VSBY.
VSBY/CIGS ARE ALSO LIKELY TO DROP TO IFR AT ART WITH A WEAK
SURFACE TROUGH WHICH WILL MOVE THROUGH LATE TONIGHT AND THURSDAY
MORNING.
ON THURSDAY AN ISOLATED SHOWER OR THUNDERSTORM MAY DEVELOP ALONG THE
SOUTH SHORE OF LAKE ONTARIO DURING THE MORNING HOURS AS A WEAK
TROUGH COMBINES WITH LAKE MOISTURE. THE FOG/BR WILL CONTINUE TO
PRODUCE AREAS OF MVFR/IFR VSBY THROUGH MID TO LATE MORNING BEFORE
MIXING OUT. BY AFTERNOON ANY ISOLATED SHOWERS OR THUNDERSTORMS WILL
FOCUS ACROSS THE HIGHER TERRAIN TO THE SOUTH OF THE THRUWAY...BUT
AGAIN COVERAGE IS EXPECTED TO REMAIN SPARSE.
OUTLOOK...
FRIDAY THROUGH MONDAY...VFR. LOCALIZED IFR IN OVERNIGHT/EARLY
MORNING FOG.
&&
.MARINE...
A WEAK TROUGH WILL CROSS THE LOWER LAKES ON THURSDAY. IN THE WAKE OF
THIS TROUGH NORTHEAST WINDS WILL INCREASE TO AROUND 15 KNOTS
THURSDAY NIGHT AND FRIDAY ON BOTH LAKES. THIS WILL PRODUCE SOME
CHOPPY WAVE ACTION...BUT CONDITIONS ARE EXPECTED TO REMAIN BELOW
SMALL CRAFT ADVISORY CRITERIA.
HIGH PRESSURE WILL THEN BUILD ALONG THE EAST COAST OVER THE LABOR
DAY HOLIDAY WEEKEND AND PROVIDE LIGHT WINDS AND FLAT WAVE ACTION
SATURDAY THROUGH MONDAY.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...HITCHCOCK
NEAR TERM...APFFEL/HITCHCOCK
SHORT TERM...APFFEL/FRANKLIN
LONG TERM...APFFEL
AVIATION...APFFEL/HITCHCOCK
MARINE...APFFEL/HITCHCOCK
AREA FORECAST DISCUSSION
NWS BUFFALO NY
226 AM EDT TUE SEP 1 2015
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN IN PLACE ACROSS THE REGION THROUGH THE
COMING WEEK. A SERIES OF WEAK UPPER LEVEL DISTURBANCES WILL BRING A
SLIGHT CHANCE OF AFTERNOON SHOWERS AND THUNDERSTORMS WEDNESDAY
THROUGH FRIDAY...BUT OTHERWISE IT WILL BE MAINLY DRY WITH SUMMERLIKE
WARMTH THROUGH THE COMING WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
MID-LEVEL RIDGE AXIS OVER THE EASTERN GREAT LAKES EARLY THIS MORNING
WORKING TOGETHER WITH SURFACE HIGH PRESSURE TO TRAP LOW LEVEL
MOISTURE NEAR THE SURFACE. KBUF VAD WIND PROFILES SHOW LIGHT
SOUTHWEST TO WEST FLOW NEAR THE SURFACE TOPPED BY STRONGER NORTHERLY
FLOW ALOFT.
HIGH DEWPOINTS CONTRIBUTING TO AREAS OF FOG SHOWING UP AT 2AM ACROSS
NEARLY THE ENTIRE AREA. WHILE DENSE FOG HAS NOT SHOWN UP JUST
YET...NEAR TERM GUIDANCE SUGGESTS IT WILL DEVELOP THROUGH THE
MORNING. THE MOST PROBABLE AREAS WILL BE ACROSS THE SOUTHERN TIER
RIVER VALLEYS AND EAST/NORTHEAST OF THE LAKES. 11-3.9 MICROWAVE
SATELLITE IMAGERY SHOWING SOME DENSE FOG/LOW CLOUDS MAY ALREADY BE
DEVELOPING JUST SOUTH OF KBUF FROM LAKE ERIE EAST TO SOUTH OF KROC
AS FLOW OFF LAKE ERIE CONTINUES TO SATURATE THE SURFACE LAYER
BENEATH THE INVERSION. HRRR GUIDANCE SHOWING MORE WIDESPREAD DENSE
FOG AND LOW STRATUS DEVELOPING FROM BUFFALO NORTH TO NIAGARA FALLS
UP TIL SUNRISE WHICH MAY REQUIRE A DENSE FOG ADVISORY IF THE
SCENARIO WORKS OUT. A SIMILAR SCENARIO MAY ALSO OCCUR ACROSS
OSWEGO/JEFFERSON COUNTIES NEAR LAKE ONTARIO.
TEMPERATURES WILL CONTINUE TO REMAIN VERY MILD THIS MORNING
REFLECTING THE HUMID AIRMASS IN PLACE ACROSS THE REGION WITH LOWS
ONLY SLIPPING IN THE LOW TO MID 60S OR MEETING DEWPOINTS.
AFTER LOW CLOUDS AND FOG BURN OFF SHORTLY AFTER DAYBREAK...SUNSHINE
AND 850MB TEMPS ABOUT +20C WILL RESULT IN MAX TEMPERATURES IN THE
80S TO AROUND 90F.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
FORECAST IN GOOD SHAPE THIS EVENING WITH JUST A FEW MINOR COSMETIC
CHANGES TO THE FORECAST GRIDS THROUGH THE SHORT TERM PERIOD. MAIN
STORY WILL CONTINUE TO BE WELL ABOVE NORMAL TEMPERATURES THIS WEEK.
UPPER LEVEL RIDGING WORKING ACROSS THE UPPER GREAT LAKES TODAY INTO
WEDNESDAY. MEANWHILE SURFACE HIGH PRESSURE CENTERED OVER THE CENTRAL
APPALACHIANS WILL CONTINUE TO ADVECT WARM AND HUMID AIR FROM THE
DEEP SOUTH NORTH INTO THE GREAT LAKES. 850 MB TEMPERATURES ARE
FORECAST TO RISE TO AROUND +20C WHICH FOR THIS TIME OF YEAR IS 1 TO
2 STANDARD DEVIATIONS ABOVE NORMAL.
THIS WILL ALL TRANSLATE INTO A CONTINUATION OF MAINLY DRY...WARM AND
HUMID WEATHER THROUGH THE MIDWEEK PERIOD. SURFACE HIGHS WILL RISE
INTO THE MID TO UPPER 80S WITH 90 POSSIBLE IN THE GENESEE VALLEY
WITH OVERNIGHT LOWS NOT PROVIDING MUCH RELIEF ONLY SLIPPING BACK
INTO THE 60S.
12Z MODELS SHOW A SUBTLE 500MB SHORTWAVE TROUGH WHICH MAY WORK
AROUND THE PERIPHERY OF THE RIDGE LATER WEDNESDAY OR WEDNESDAY
NIGHT. THIS MAY BE ENOUGH TO TRIGGER SOME ISOLATED STORMS INN OUR
WARM AND HUMID AIRMASS. ANY STORM THAT DEVELOPS WOULD LIKELY BE
ELEVATED AS FORECAST SOUNDINGS SHOW AND ELEVATED MIXED LAYER ABOVE A
700MB INVERSION. HAVE COVERED THIS WITH SLIGHT CHANCE POPS OVER THE
ENTIRE FORECAST AREA AS LAKE INFLUENCES WOULD NOT BE A FACTOR IN
ELEVATED CONVECTION.
LATEST MODELS ALSO CONTINUE TO SHOW A WEAK BACKDOOR COLD FRONT
CROSSING SOUTH ACROSS LAKE ONTARIO THURSDAY AS A SURFACE HIGH
PRESSES SOUTH ACROSS QUEBEC. ISOLATED CONVECTION CANNOT BE
COMPLETELY RULED OUT WITH MODEST INSTABILITY DEVELOPING INLAND FROM
THE LAKES.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
12Z MEDIUM RANGE GUIDANCE CONTINUES TO SUGGEST THAT THE AXIS OF THE
STRONG UPPER LEVEL RIDGE WILL BUILD DIRECTLY ACROSS THE LOWER GREAT
LAKES AND NEW YORK STATE. WITH OUR AIRMASS THUS LIKELY TO BE
STRONGLY CAPPED...WILL CONTINUE TO ADVERTISE MAINLY DRY WEATHER
THROUGH THE PERIOD WITH ONLY ISOLATED CONVECTION POSSIBLE DURING THE
AFTERNOON HEATING CYCLE.
OTHERWISE...THE DOMINANT RIDGING WILL LEAD TO MIDSUMMER-LIKE
WARMTH AND HUMIDITY CONTINUING ACROSS OUR REGION...WITH DAYTIME
HIGHS AGAIN AVERAGING IN THE MID 80S...AND NIGHTTIME LOWS MAINLY
RANGING IN THE LOWER TO MID 60S.
&&
.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
HIGH PRESSURE REMAINS FIRMLY IN CONTROL ACROSS THE LOWER GREAT LAKES
TRAPPING MOISTURE NEAR THE SURFACE. AREAS OF MVFR/IFR FOG ARE
DEVELOPING ACROSS THE REGION AT 6Z. NEAR TERM GUIDANCE INCLUDING THE
HRRR SUGGEST LIFR OR LOWER VIS AND CIGS WILL DEVELOP TOWARD 10Z AT
ALL SITES AS LIGHT FLOW OFF THE GREAT LAKES INCREASES LOW LEVEL
MOISTURE. KROC MAY NOT GO AS LOW AS LIFR BUT IFR LIKELY.
ANY FOG AND LOW CLOUDS WILL DISSIPATE BY 14-16Z THIS MORNING LEAVING
SUNNY VFR SKIES GOING INTO THE AFTERNOON.
.
OUTLOOK...
TUESDAY NIGHT AND WEDNESDAY...VFR. LOCALIZED IFR IN PATCHY LATE
NIGHT/EARLY MORNING VALLEY FOG IN THE SOUTHERN TIER.
THURSDAY AND FRIDAY...MAINLY VFR WITH A SLIGHT CHANCE OF
AFTERNOON SHOWERS AND THUNDERSTORMS.
SATURDAY...VFR.
&&
.MARINE...
HIGH PRESSURE WILL REMAIN IN PLACE ACROSS THE REGION THROUGHOUT THE
UPCOMING WEEK. HIGH DEWPOINT AIR OVER THE REGION WILL KEEP AREAS OF
FOG IN PLACE AT LEAST EACH MORNING. PREVAILING SW FLOW WILL ENHANCE
LAKE BREEZES IN THE AFTERNOONS...PRODUCING A LIGHT CHOP ON THE
EASTERN ENDS OF THE LAKES...HOWEVER WINDS/WAVES WILL REMAIN 12
KNOTS/2FT OR LESS THROUGH THE PERIOD.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...FRANKLIN
NEAR TERM...SMITH
SHORT TERM...HITCHCOCK/TMA
LONG TERM...TMA
AVIATION...SMITH
MARINE...FRANKLIN/SMITH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
144 AM EDT TUE SEP 1 2015
.SYNOPSIS...
LOW PRESSURE ALONG THE NORTH CAROLINA COAST SHOULD MOVE NORTHEAST
AND AWAY FROM THE AREA OVERNIGHT. A LINGERING TROUGH WILL REMAIN
ACROSS THE EASTERN CAROLINAS ON TUESDAY. HIGH PRESSURE WILL BUILD
INTO THE AREA FROM THE NORTH FRIDAY NIGHT AND THROUGH THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 130 AM TUESDAY...NO CHANGES TO THE FORECAST WITH THE LATEST
UPDATE. PREVIOUS DISCUSSION FOLLOWS:
INLAND SHOWERS HAVE DISSIPATED BUT ISOLATED ACTIVITY CONTINUES
OFFSHORE...MOVING EASTWARD. BASED ON SURFACE WIND DIRECTIONS AT
BUOYS AND MESONET SITES THE LOW APPEARS TO HAVE MOVED TO A
POSITION 10-15 MILES EAST OF TOPSAIL ISLAND. THE LATEST RUC MODEL
ISN`T BAD AND WAS BLENDED INTO OUR WIND GRIDDED DATASET FOR THE
REMAINDER OF THE NIGHT.
LOW CLOUDS HAVE DEVELOPED A FEW HOURS MORE QUICKLY THAN
ANTICIPATED. CLOUDINESS CURRENTLY EXTENDING FROM ELIZABETHTOWN
TO WHITEVILLE SHOULD GRADUALLY EXPAND AFTER MIDNIGHT TO COVER
MOST OF SE NORTH CAROLINA AND SOME PARTS OF NE SOUTH CAROLINA AS
WELL. DISCUSSION FROM 730 PM FOLLOWS...
THE DEEP TROPICAL MOISTURE CHANNEL IS FINALLY BEGINNING TO SHIFT
OFFSHORE. WATER VAPOR IMAGERY SHOWS THE LEADING/EASTERN EDGE OF
THE DRY AIR NOW ON THE NORTH CAROLINA COAST. LOCALLY HEAVY RAIN
CONTINUES TO FALL HOWEVER AS SURFACE LOW PRESSURE AND ITS
ASSOCIATED MAXIMUM IN LOW-LEVEL CONVERGENCE IS CENTERED JUST EAST
OF CAPE FEAR. THE 12/18Z MODELS WERE QUITE POOR WITH THE ACCURACY
OF THE POSITION OF THIS LOW. OF ALL THE MODELS AVAILABLE TO US
ONLY THE 12Z WRF-NMM AND 12Z WRF-ARW SHOWED THE LOW IN THE PROPER
POSITION AT 21Z. THESE TWO MODELS ARE THE BASIS FOR THE UPDATED
FORECAST THIS EVENING.
THE LOW SHOULD MOVE NORTHEASTWARD THIS EVENING AND AWAY FROM
SOUTHEASTERN NORTH CAROLINA. RAINFALL SHOULD SLOWLY TAPER OFF OVER
THE NEXT 2-3 HOURS...LINGERING FOR COASTAL PENDER COUNTY AND THE
ADJACENT OCEAN WATERS THE LONGEST. AN ADDITIONAL ONE-HALF INCH TO
ONE INCH OF RAIN COULD POTENTIALLY FALL FROM WRIGHTSVILLE BEACH
TO TOPSAIL ISLAND OVER THE NEXT FEW HOURS.
ONCE THE PRECIP CLEARS THE COAST...CLEAR SKIES ADVANCING IN FROM
THE WEST SHOULD OVERSPREAD MOST OF THE AREA. HOWEVER...MODELS ARE
INDICATING WRAP-AROUND MOISTURE WILL RE-ENTER THE PICTURE FROM THE
NORTH...SPREADING A DECK OF LOW STRATUS INTO AT LEAST
SOUTHEASTERN NORTH CAROLINA AFTER MIDNIGHT. WHERE THESE LOW CLOUDS
DO NOT REACH...BETTER RADIATIONAL COOLING CONDITIONS WILL
INTERSECT WITH LINGERING SURFACE MOISTURE AND WE CAN EXPECT AREAS
OF FOG TO DEVELOP. MOS GUIDANCE IS INDICATING THIS FOG COULD
BECOME LOCALLY DENSE...PARTICULARLY ACROSS SOUTH CAROLINA`S PEE
DEE REGION.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY NIGHT/...
AS OF 300 PM MONDAY...PROGRESSIVE PATTERN THROUGH THE PERIOD. A
TROUGH OF LOW PRESSURE WILL BE ALIGNED RIGHT ALONG THE COAST TUE.
A MID-LEVEL VORTICITY MAXIMA ASSOCIATED WITH FORMER TROPICAL
STORM ERIKA WILL BE MOVING UP THE SOUTHEAST COAST. THIS FEATURE
WILL BE APPROACHING THE FORECAST AREA TUE NIGHT AND IS EXPECTED TO
MOVE OFF THE CAROLINA COAST DURING THE DAY WED. A RIDGE BUILDING
ACROSS THE MIDDLE OF THE COUNTRY NEAR THE END OF THE PERIOD WILL
ALLOW A NW FLOW TO DEVELOP ACROSS THE CAROLINAS. A WEAK SHORTWAVE
EMBEDDED IN THE FLOW IS FORECAST TO APPROACH LATE WED NIGHT.
THERE WILL BE A GOOD AMOUNT OF DRY AIR MOVING ACROSS THE AREA AND
THIS IN AND OF ITSELF WILL BE GOOD REASON TO KEEP THE POPS IN
SLIGHT CHANCE/CHANCE CATEGORY. WILL SHOW HIGHEST POPS ALONG THE
COAST AHEAD OF AFOREMENTIONED MID-LEVEL VORTICITY...LATE TUE
NIGHT AND WED MORNING. HOWEVER...IT MAY END UP THAT MOST OF THE
PRECIPITATION AND CERTAINLY THE HEAVIEST OF THE SHOWER AND
THUNDERSTORM ACTIVITY...WILL BE OFFSHORE. WILL ALSO TRY TO
CAPTURE THE SLIGHT UPTICK IN THE POTENTIAL FOR CONVECTION WED
NIGHT WITH THE MID-LEVEL SHORTWAVE.
TEMPERATURES WILL RETURN TO SLIGHTLY ABOVE SEASONABLE LEVELS FOR
EARLY SEPTEMBER.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 300 PM MONDAY...THURSDAY SHOULD BE THE FIRST FULL DAY WHERE THE
AREA IS NO LONGER DEALING WITH ANY REMNANTS OF ERIKA. PW DROPS TO
ABOUT 1.6 INCHES ACROSS MUCH OF THE AREA BUT THERE WILL BE A MID
LEVEL DISTURBANCE MOVING THROUGH IN NORTHWEST FLOW. GFS NOW SHOWS A
VERY WEAK ATTENDANT SURFACE FEATURE AND SO FEEL THAT THE LOW END
SCATTERED (30 POPS) THAT WE HAVE IN THE FORECAST IS JUST FINE. QPF
PROSPECTS WILL BE LOW DUE TO THE LOWER AVAILABLE MOISTURE AND WEAK
FORCING. ANOTHER MID LEVEL FEATURE CROSSES ON FRIDAY BUT IN MORE OF
WESTERLY RATHER THAN NORTHWESTERLY SOURCE WHICH MAY FAVOR BETTER
RAIN CHANCES DUE TO DEEPER MOISTURE AT LEAST ACCORDING TO ECMWF. GFS
HAS MORE OF A REPEAT OF THURSDAY. LARGE UPPER RIDGE BUILDS OVER THE
EASTERN U.S. AND MID-ATLANTIC OVER THE WEEKEND WITH ITS CENTER
WELL TO OUR NORTH. THE SAME WILL HOLD TRUE AT THE SURFACE. THIS
WILL BRING A DEEP EASTERLY FLOW TO THE AREA THAT OFTEN LEADS TO
TROPICAL BLUE SKIES LADEN WITH TOWERING CU AND ALSO A FEW STRAY
SHOWERS MAINLY ALONG THE COAST.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 06Z...A MIXTURE OF VFR/MVFR/IFR ON TAP OVERNIGHT WELL INTO THE
EARLY MORNING HOURS AS AREAS OF FOG AND LOW CIGS DEVELOP. CONDITIONS
IMPROVE TO VFR LATE TUESDAY MORNING AND CONTINUE THROUGH THE END OF
THE VALID TAF PERIOD.
SOME OBSERVATIONS ARE BEGINNING TO SHOW FEW/SCT LOW CIGS MOVING
ACROSS PORTIONS OF THE AREA...BUT OVERALL SKIES ARE CLEAR AND WINDS
ARE LIGHT. GUIDANCE CONTINUES TO INDICATE INCREASING MOISTURE
OVERNIGHT AND AS A RESULT ANTICIPATE STRATUS AND FOG DEVELOPMENT TO
CREATE MVFR/IFR CONDITIONS. CONFIDENCE REMAINS LOW REGARDING WHICH
FEATURE WILL PREVAIL...THUS HAVE KEPT A MIXTURE IN GOING FORECAST
ATTM. ON TUESDAY...CONDITIONS WILL IMPROVE TO VFR WITH LIGHT WINDS
BECOMING SOUTHEAST AOB 10 KTS IN THE AFTERNOON. CANNOT ENTIRELY RULE
OUT AN ISOLATED SHRA/TSRA IN THE AFTERNOON HOURS. TOWARDS THE
EVENING HOURS...EXPECT VFR TO PREVAIL WITH WINDS BECOMING LIGHT.
EXTENDED OUTLOOK...PREDOMINATELY VFR WITH BRIEF MORNING FOG AND
ISOLATED/SCATTERED AFTERNOON CONVECTION.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 130 AM TUESDAY...NO CHANGES TO THE FORECAST WITH THE LATEST
UPDATE. PREVIOUS DISCUSSION FOLLOWS:
OBSERVATIONS SUGGEST THE LOW IS CURRENTLY LOCATED 10-15 MILES
EAST OF TOPSAIL ISLAND AND MOVING NORTHEASTWARD. ISOLATED SHOWERS
CONTINUE ACROSS THE NC COASTAL WATERS BUT SHOULD END OVER THE NEXT
FEW HOURS. A BELT OF STRONGER SOUTH-SOUTHWEST WINDS OFFSHORE AHEAD
OF THE LOW HAS BUILT SEA HEIGHTS AT THE FRYING PAN SHOALS BUOY TO
5 FEET...WITH BUOYS CLOSE TO THE COAST STILL REPORTING 3-4 FEET.
DISCUSSION FROM 730 PM FOLLOWS...
USING RADAR IMAGERY AND SURFACE OBSERVATIONS LOW PRESSURE IS
CENTERED JUST EAST OF CAPE FEAR AT 7 PM. OF ALL THE MODELS
AVAILABLE TO US THE TWO THAT SEEM TO HAVE THE BEST HANDLE ON THE
CURRENT POSITION AND MOVEMENT OF THIS FEATURE ARE THE 12Z WRF-NMM
AND 12Z WRF-ARW. THESE MODELS ARE THE BASIS FOR THIS EVENING
UPDATE. OFFSHORE WINDS SHOULD GRADUALLY DIMINISH THROUGH THE NIGHT
SOUTH OF CAPE FEAR...BUT NORTH OF CAPE FEAR WE`VE GOT A FEW MORE
HOURS OF INTERESTING WEATHER AS SWIRLING WINDS UP TO 20 KNOTS AND
WIDESPREAD SHOWERS WITH HEAVY RAINFALL WILL CONTINUE. SEAS HAVE
BUILT TO A SOLID 4 FEET NEAR AND NORTH OF CAPE FEAR AND THERE
SHOULD BE SOME 5-FOOTERS DEVELOPING SHORTLY ACCORDING TO OUR LOCAL
WAVE MODEL USING UPDATED WIND FORECASTS. AN EXERCISE CAUTION
HEADLINE HAS BEEN HOISTED NORTH OF CAPE FEAR. AFTER MIDNIGHT SEAS
SHOULD SUBSIDE THROUGHOUT THE REGION TO 2-3 FEET.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 PM MONDAY...A SLACK PRESSURE GRADIENT IS EXPECTED TO BE
IN PLACE THROUGH THE PERIOD AND THIS SHOULD KEEP WIND SPEEDS TO
10 KT OR LESS. SW TO S WINDS DURING THE AFTERNOON AND EVE BOTH
DAYS SHOULD BECOME MORE OFFSHORE OVERNIGHT AND DURING THE MORNING
DUE TO A LAND BREEZE MOVING OFFSHORE. SEAS WILL BE MAINLY 2
FT...BUT UP TO 3 FT TUE. A WEAK 8 TO 10 SECOND SE SWELL WILL
PERSIST.
LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 300 PM MONDAY...WIND SPEEDS WILL BE CAPPED AT JUST 10 KNOTS
THROUGH MOST OF IF NOT THE ENTIRE PERIOD. IT MAY STRUGGLE THURSDAY
AND FRIDAY TO FIND AN ESTABLISHED DIRECTION HOWEVER THOUGH NORTH AND
EAST COMPONENTS WILL TEND TO BE FAVORED. THIS WILL BE FORTIFIED
FRIDAY NIGHT INTO SATURDAY AS A STRONGER HIGH GETS ESTABLISHED
ACROSS NORTHEASTERN U.S. BETWEEN THE LENGTHENING SPATIAL AND
TEMPORAL FETCH ON SATURDAY THE WAVE FORECAST MAY RISE FROM 2 TO 2-3
FT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...RJD
NEAR TERM...REK/TRA
SHORT TERM...RJD
LONG TERM...MBB
AVIATION...SGL
MARINE...REK/RJD/TRA/MBB
AREA FORECAST DISCUSSION
NWS BISMARCK ND
948 PM CDT WED SEP 2 2015
.UPDATE...
ISSUED AT 943 PM CDT WED SEP 2 2015
NO CHANGES TO THE GOING FORECAST.
UPDATE ISSUED AT 754 PM CDT WED SEP 2 2015
MONTANA SHOWERS DISSIPATED AS THEY NEARED THE NORTH DAKOTA BORDER.
UPDATED TO DRY OUT THE FORECAST.
UPDATE ISSUED AT 441 PM CDT WED SEP 2 2015
WILL NEED TO DO A FORECAST UPDATE TO ACCOUNT FOR SHOWERS MOVING
FROM THE MILES CITY TO GLENDIVE AREA OF MONTANA TOWARD THE NORTH
DAKOTA BORDER. THE HRRR IS HANDLING THE PRECIPITATION THE BEST AS
COMPARED TO OTHER HI RES SHORT TERM MODELS. THE HRRR HAS THE
SHOWERS DEPICTED...AND BRINGS THEM INTO NORTH DAKOTA...EVEN INTO
THE CENTRAL PART OF THE STATE LATER.
KMLS ASOS HAD A WIND GUST OF 52 KNOTS...60 MPH...HOWEVER...THE
STATION REPORTED NO THUNDER AND THE LIGHTNING NETWORK SHOWED NO
LIGHTNING. SO...IT WAS A SHOWER THAT MIXED DOWN HIGHER WIND AND
LIKELY EVAPORATION ADDED TO THE DOWNWARD TRANSPORT. DOWNDRAFT CAPE
IS ANALYZED 1700-1800 UNITS ACROSS WESTERN NORTH DAKOTA.
WILL ADD POPS TO THE WEST AND MAY NEED TO BRING THEM INTO THE
CENTRAL PART OF THE STATE ON A LATER UPDATE. WILL THE ACTIVITY
HOLD TOGETHER AS DEPICTED BY THE HRRR...IS THE QUESTION.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 330 PM CDT WED SEP 2 2015
MAIN CONCERNS THIS PERIOD WILL BE SOME PATCHY FOG TONIGHT...
AND TEMPERATURES AND SOME SLIGHT CHANCES FOR THUNDERSTORMS ALONG
A SLOWLY MOVING FRONTAL BOUNDARY ACROSS THE NORTHWEST ON THURSDAY.
TONIGHT...THE H500 FLOW REMAINS ORIENTED SOUTHWEST TO NORTHEAST.
EXPECT THE COLD FRONTAL BOUNDARY WHICH IS ALIGNED WITH THE FLOW
ALOFT TO ONLY MOVE SLOWLY EAST TONIGHT AND THURSDAY. THIS WILL
GIVE THE REGION ANOTHER OPPORTUNITY FOR VERY WARM TEMPERATURES
THURSDAY ALONG AND AHEAD OF THE FRONT. HIGHS CENTRAL SECTIONS WILL
BE CLOSE TO 100. RELATIVELY COOLER AIR...ALTHOUGH STILL IN THE
MID 80S...WILL MOVE INTO THE NORTHWEST. LOW LEVEL MOISTURE
POOLING ALONG THE JAMES RIVER VALLEY TONIGHT WILL FAVOR MUGGY
CONDITIONS AND SOME PATCHY FOG TONIGHT WITH DEWPOINTS AROUND 70.
ON THURSDAY THE HEAT INDEX VALUES WILL RISE TO NEAR 100 ACROSS THE
JAMES RIVER VALLEY BY AFTERNOON.
THE NAM/GFS BOTH DEVELOP SOME WEAK CONVECTION ALONG THE FRONTAL
BOUNDARY THURSDAY. THE WRF MODEL DOES TOO BUT IN THE AFTERNOON.
WILL ADD ISOLATED THUNDERSTORMS FAR WEST INTO THE NORTH CENTRAL
THURSDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 330 PM CDT WED SEP 2 2015
A SIGNIFICANT PATTERN CHANGE WILL IMPACT THE NORTHERN PLAINS FOR
THE UPCOMING HOLIDAY WEEKEND...WITH COOLER AND WETTER CONDITIONS.
STRONG UPPER LEVEL LOW DROPPING INTO THE PACIFIC NORTHWEST TODAY
WILL BECOME AN OPEN WAVE AND DEEPEN OVER THE WEST COAST THROUGH
SATURDAY. BY THURSDAY NIGHT EMBEDDED S/WV IMPULSES WILL BEGIN TO
APPROACH THE REGION...AND WHEN COUPLED WITH A SLOW MOVING SFC
BOUNDARY WILL RESULT IN CHANCES FOR SHOWERS/THUNDERSTORMS WEST TO
EAST DURING THE NIGHT. A PARTICULARLY STRONG EMBEDDED WAVE WILL
LIFT NORTHEAST ACROSS THE DAKOTAS LATE THURSDAY NIGHT/FRIDAY
MORNING AND MAY BRING MODERATE TO HEAVY RAIN TO PORTIONS OF NORTH
CENTRAL AND EASTERN NORTH DAKOTA DURING THAT TIMEFRAME.
FRIDAY-SATURDAY THE WEST COAST UPPER TROUGH BEGINS TO MOVE FARTHER
INLAND AND WILL DIRECT A SERIES OF SHORTWAVE ENERGY IMPULSES ACROSS
THE NORTHERN PLAINS. THE EXPECTED INCREASE IN CLOUD COVER AND CAA
IN THE WAKE OF THE SFC FRONT WILL RESULT IN MUCH COOLER
TEMPERATURES...WITH HIGHS DROPPING INTO THE 70S MOST AREAS BY
SATURDAY. SATURDAY NIGHT INTO SUNDAY THE BASE OF THE UPPER TROUGH
LIFTS NORTHEASTWARD ACROSS THE ROCKIES AND INTO THE NORTHERN
PLAINS...REACHING FAR SOUTH CENTRAL CANADA SUNDAY NIGHT. THIS
TIME PERIOD (FRIDAY-SUNDAY) WILL SEE VERY GOOD CHANCES FOR SHOWERS
AND THUNDERSTORMS. HEAVIEST PRECIPITATION FORECAST ACROSS THE
NORTH. TOTAL RAINFALL THURSDAY NIGHT THROUGH SUNDAY IS FORECAST TO
RANGE FROM AROUND HALF AN INCH SOUTHWEST...TO NEAR 2 INCHES NORTH.
HEAVIER AMOUNTS VERY POSSIBLE WITH THUNDERSTORMS. INSTABILITY NOT
OVERLY IMPRESSIVE SO WHILE A FEW STRONGER STORMS MAY FORM...THE
OVERALL SEVERE THREAT WILL BE MINIMAL.
MUCH COOLER IN THE WAKE OF THE STORM SYSTEM MONDAY...WITH FORECAST
HIGHS MID 60S TO LOW 70S. A QUASI-ACTIVE UPPER LEVEL ZONAL FLOW
SETS UP EARLY TO MID NEXT. THIS IS A DEVIATION FROM PREVIOUS
MODELS SO UNCERTAINTY RATHER HIGH AT THIS POINT. STILL LOOKS LIKE
A SLOW MODERATION IN TEMPERATURES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 945 PM CDT WED SEP 2 2015
LOW PRESSURE IN EASTERN MONTANA WILL CONTINUE TO BRING SOUTHERLY
SURFACE FLOW INTO THE REGION. PATCHY FOG IS POSSIBLE TOWARD
DAYBREAK THURSDAY ESPECIALLY IN RIVER VALLEYS OVER THE CENTRAL AND
EAST. VSBYS IN TAFS FOR KBIS AND KJMS WERE POSTED WITH 5SM FROM
11Z/12Z TO 15Z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JPM
SHORT TERM...WAA
LONG TERM...NH
AVIATION...JPM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
755 PM CDT WED SEP 2 2015
.UPDATE...
ISSUED AT 754 PM CDT WED SEP 2 2015
MONTANA SHOWERS DISSIPATED AS THEY NEARED THE NORTH DAKOTA BORDER.
UPDATED TO DRY OUT THE FORECAST.
UPDATE ISSUED AT 441 PM CDT WED SEP 2 2015
WILL NEED TO DO A FORECAST UPDATE TO ACCOUNT FOR SHOWERS MOVING
FROM THE MILES CITY TO GLENDIVE AREA OF MONTANA TOWARD THE NORTH
DAKOTA BORDER. THE HRRR IS HANDLING THE PRECIPITATION THE BEST AS
COMPARED TO OTHER HI RES SHORT TERM MODELS. THE HRRR HAS THE
SHOWERS DEPICTED...AND BRINGS THEM INTO NORTH DAKOTA...EVEN INTO
THE CENTRAL PART OF THE STATE LATER.
KMLS ASOS HAD A WIND GUST OF 52 KNOTS...60 MPH...HOWEVER...THE
STATION REPORTED NO THUNDER AND THE LIGHTNING NETWORK SHOWED NO
LIGHTNING. SO...IT WAS A SHOWER THAT MIXED DOWN HIGHER WIND AND
LIKELY EVAPORATION ADDED TO THE DOWNWARD TRANSPORT. DOWNDRAFT CAPE
IS ANALYZED 1700-1800 UNITS ACROSS WESTERN NORTH DAKOTA.
WILL ADD POPS TO THE WEST AND MAY NEED TO BRING THEM INTO THE
CENTRAL PART OF THE STATE ON A LATER UPDATE. WILL THE ACTIVITY
HOLD TOGETHER AS DEPICTED BY THE HRRR...IS THE QUESTION.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 330 PM CDT WED SEP 2 2015
MAIN CONCERNS THIS PERIOD WILL BE SOME PATCHY FOG TONIGHT...
AND TEMPERATURES AND SOME SLIGHT CHANCES FOR THUNDERSTORMS ALONG
A SLOWLY MOVING FRONTAL BOUNDARY ACROSS THE NORTHWEST ON THURSDAY.
TONIGHT...THE H500 FLOW REMAINS ORIENTED SOUTHWEST TO NORTHEAST.
EXPECT THE COLD FRONTAL BOUNDARY WHICH IS ALIGNED WITH THE FLOW
ALOFT TO ONLY MOVE SLOWLY EAST TONIGHT AND THURSDAY. THIS WILL
GIVE THE REGION ANOTHER OPPORTUNITY FOR VERY WARM TEMPERATURES
THURSDAY ALONG AND AHEAD OF THE FRONT. HIGHS CENTRAL SECTIONS WILL
BE CLOSE TO 100. RELATIVELY COOLER AIR...ALTHOUGH STILL IN THE
MID 80S...WILL MOVE INTO THE NORTHWEST. LOW LEVEL MOISTURE
POOLING ALONG THE JAMES RIVER VALLEY TONIGHT WILL FAVOR MUGGY
CONDITIONS AND SOME PATCHY FOG TONIGHT WITH DEWPOINTS AROUND 70.
ON THURSDAY THE HEAT INDEX VALUES WILL RISE TO NEAR 100 ACROSS THE
JAMES RIVER VALLEY BY AFTERNOON.
THE NAM/GFS BOTH DEVELOP SOME WEAK CONVECTION ALONG THE FRONTAL
BOUNDARY THURSDAY. THE WRF MODEL DOES TOO BUT IN THE AFTERNOON.
WILL ADD ISOLATED THUNDERSTORMS FAR WEST INTO THE NORTH CENTRAL
THURSDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 330 PM CDT WED SEP 2 2015
A SIGNIFICANT PATTERN CHANGE WILL IMPACT THE NORTHERN PLAINS FOR
THE UPCOMING HOLIDAY WEEKEND...WITH COOLER AND WETTER CONDITIONS.
STRONG UPPER LEVEL LOW DROPPING INTO THE PACIFIC NORTHWEST TODAY
WILL BECOME AN OPEN WAVE AND DEEPEN OVER THE WEST COAST THROUGH
SATURDAY. BY THURSDAY NIGHT EMBEDDED S/WV IMPULSES WILL BEGIN TO
APPROACH THE REGION...AND WHEN COUPLED WITH A SLOW MOVING SFC
BOUNDARY WILL RESULT IN CHANCES FOR SHOWERS/THUNDERSTORMS WEST TO
EAST DURING THE NIGHT. A PARTICULARLY STRONG EMBEDDED WAVE WILL
LIFT NORTHEAST ACROSS THE DAKOTAS LATE THURSDAY NIGHT/FRIDAY
MORNING AND MAY BRING MODERATE TO HEAVY RAIN TO PORTIONS OF NORTH
CENTRAL AND EASTERN NORTH DAKOTA DURING THAT TIMEFRAME.
FRIDAY-SATURDAY THE WEST COAST UPPER TROUGH BEGINS TO MOVE FARTHER
INLAND AND WILL DIRECT A SERIES OF SHORTWAVE ENERGY IMPULSES ACROSS
THE NORTHERN PLAINS. THE EXPECTED INCREASE IN CLOUD COVER AND CAA
IN THE WAKE OF THE SFC FRONT WILL RESULT IN MUCH COOLER
TEMPERATURES...WITH HIGHS DROPPING INTO THE 70S MOST AREAS BY
SATURDAY. SATURDAY NIGHT INTO SUNDAY THE BASE OF THE UPPER TROUGH
LIFTS NORTHEASTWARD ACROSS THE ROCKIES AND INTO THE NORTHERN
PLAINS...REACHING FAR SOUTH CENTRAL CANADA SUNDAY NIGHT. THIS
TIME PERIOD (FRIDAY-SUNDAY) WILL SEE VERY GOOD CHANCES FOR SHOWERS
AND THUNDERSTORMS. HEAVIEST PRECIPITATION FORECAST ACROSS THE
NORTH. TOTAL RAINFALL THURSDAY NIGHT THROUGH SUNDAY IS FORECAST TO
RANGE FROM AROUND HALF AN INCH SOUTHWEST...TO NEAR 2 INCHES NORTH.
HEAVIER AMOUNTS VERY POSSIBLE WITH THUNDERSTORMS. INSTABILITY NOT
OVERLY IMPRESSIVE SO WHILE A FEW STRONGER STORMS MAY FORM...THE
OVERALL SEVERE THREAT WILL BE MINIMAL.
MUCH COOLER IN THE WAKE OF THE STORM SYSTEM MONDAY...WITH FORECAST
HIGHS MID 60S TO LOW 70S. A QUASI-ACTIVE UPPER LEVEL ZONAL FLOW
SETS UP EARLY TO MID NEXT. THIS IS A DEVIATION FROM PREVIOUS
MODELS SO UNCERTAINTY RATHER HIGH AT THIS POINT. STILL LOOKS LIKE
A SLOW MODERATION IN TEMPERATURES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 330 PM CDT WED SEP 2 2015
AT 3 PM CDT...LOW PRESSURE ACROSS MONTANA WAS BRINGING SOUTHERLY
FLOW INTO THE REGION. VFR CONDITIONS ARE EXPECTED THROUGH THE TAF
PERIOD. SOME PATCHY FOG IS POSSIBLE IN THE JAMES RIVER VALLEY
THURSDAY MORNING. AT THIS TIME KEPT VSBYS AT 5 MILES OR GREATER
KBIS-KJMS AFTER 12Z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JPM
SHORT TERM...WAA
LONG TERM...NH
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
600 PM CDT TUE SEP 1 2015
.UPDATE...
ISSUED AT 554 PM CDT TUE SEP 1 2015
DID ADD A MENTION OF FOG TO MUCH OF CENTRAL NORTH DAKOTA TONIGHT
AS 60S F DEWPOINTS CONTINUE TO ADVECT NORTH EARLY THIS
EVENING...WITH LIGHT WINDS AND CLEAR SKIES THROUGH THE OVERNIGHT.
THE 21 UTC HRRR AND 18 UTC NAM NEST SUPPORT THIS POTENTIAL VIA
THEIR REDUCED VISIBILITY FORECASTS ACROSS CENTRAL NORTH DAKOTA
LATE TONIGHT INTO EARLY WEDNESDAY MORNING.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 310 PM CDT TUE SEP 1 2015
THIS AFTERNOON...A WEAK SURFACE LOW PRESSURE TROUGH AND
ASSOCIATED WARM FRONT OVER CENTRAL SOUTH DAKOTA WAS A REFLECTION
OF A WEAKENING SHORT WAVE TROUGH ALOFT. THIS FEATURE IS FORECAST
TO MEANDER NORTHEAST WHILE DIMINISHING WITH TIME. SOUTHERLY LOW
LEVEL FLOW OVER THE WARM FRONT WILL TRANSFER MOISTURE NORTH INTO
THE JAMES RIVER VALLEY WHERE SEVERAL HIGH RESOLUTION MODELS AS
WELL AS THE GFS/NAM FORECAST SOME CONVECTION OVERNIGHT. WILL NEED
SOME TIME TO DEVELOP THIS SCENARIO SO DELAYED THE ONSET OF
CONVECTION UNTIL MIDNIGHT. OTHERWISE THIS FORCING WILL END/SHIFT
TO THE EAST ON WEDNESDAY. SKIES WILL BE MOSTLY SUNNY WEDNESDAY.
WITH A BROAD THERMAL RIDGE OVER EASTERN MONTANA AND NORTH DAKOTA
HIGHS WILL WARM WELL INTO THE 90S. HUMIDITY WILL BE LOW WITH
AFTERNOON VALUES REACHING 15 PERCENT WEST. THE MAJOR MISSING
COMPONENT WAS WINDS FOR FIRE WEATHER CONCERNS. WINDS WILL REMAIN
BELOW 15 MPH FOR THE MOST PART WEDNESDAY AFTERNOON.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 310 PM CDT TUE SEP 1 2015
CONTINUED VERY WARM WEDNESDAY INTO THURSDAY...FOLLOWED BY A
SIGNIFICANT PATTERN CHANGE FOR THE UPCOMING HOLIDAY WEEKEND.
STRONG UPPER LEVEL LOW DROPPING INTO THE PACIFIC NORTHWEST
WEDNESDAY WILL BECOME AN OPEN WAVE AND DEEPEN OVER THE WEST COAST
THROUGH SATURDAY. DURING THIS TIME NORTH DAKOTA WILL REMAIN ON THE
WESTERN EDGE OF THE UPSTREAM RIDGE AXIS...KEEPING VERY WARM AND
DRY AIR OVER THE STATE. HIGHS THURSDAY WILL ONCE AGAIN REACH INTO
THE 90S MANY LOCATIONS...WITH 80S NORTHWEST IN THE WAKE OF A SLOW
MOVING FRONTAL BOUNDARY. BY THURSDAY NIGHT EMBEDDED S/WV IMPULSES
WILL APPROACH THE REGION...AND WHEN COUPLED WITH THE BOUNDARY WILL
RESULT IN CHANCES FOR SHOWERS/THUNDERSTORMS WEST TO EAST DURING
THE NIGHT.
FRIDAY-SATURDAY THE WEST COAST UPPER TROUGH BEGINS TO MOVE FARTHER
INLAND AND WILL DIRECT A SERIES OF SHORTWAVE ENERGY IMPULSES ACROSS
THE NORTHERN PLAINS. THE EXPECTED INCREASE IN CLOUD COVER AND CAA
IN THE WAKE OF THE SFC FRONT WILL RESULT IN MUCH COOLER
TEMPERATURES...WITH HIGHS DROPPING INTO THE MID 60S NORTHWEST TO
LOW 80S OVER THE SOUTHERN JAMES RIVER VALLEY BY SATURDAY. SATURDAY
NIGHT INTO SUNDAY THE BASE OF THE TROUGH LIFTS NORTHEASTWARD INTO
THE NORTHERN PLAINS...REACHING SOUTHERN CANADA BY SUNDAY NIGHT.
THIS TIME PERIOD (FRIDAY-SUNDAY) WILL SEE VERY GOOD CHANCES FOR
SHOWERS AND THUNDERSTORMS.
A MORE ZONAL FLOW SETS UP EARLY NEXT WEEK AND SHOULD RESULT IN
MAINLY DRY CONDITIONS AND SOME TEMPERATURE RECOVERY AS WE PROGRESS
INTO THE MIDDLE PORTIONS OF THE WORK WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 554 PM CDT TUE SEP 1 2015
FOG MAY BE POSSIBLE AT KJMS/KBIS LATE TONIGHT INTO EARLY WEDNESDAY
MORNING WITH IFR VISIBILITY POSSIBLE. OTHERWISE...VFR CONDITIONS
FORECAST FOR THE 00 UTC TAF CYCLE.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...WAA
LONG TERM...NH
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
334 PM CDT TUE SEP 1 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 325 PM CDT TUE SEP 1 2015
500 MB SHORT WAVE NOTED IN SOUTHEASTERN SOUTH DAKOTA MOVING
NORTHEAST. A BAND OF SHOWERS ARE WITH THIS SYSTEM. FOR TONIGHT
QUESTION IS PRECIP CHANCES OVERNIGHT INTO WED MORNING MAINLY FOR
NE ND INTO NW MN. FOR THE PAST COUPLE OF DAYS MODELS HAVE
INDICATED THREAT FOR SOME CONVECTION TO DEVELOP NR 06Z IN THE MID
RRV AND THE MOVE NORTHEAST THROUGH LAKE OF THE WOODS REGION BY
12Z. 12Z MODELS TODAY SHOW TO SOME DEGREE THE SAME THING...BUT
MORE GFS IN THIS CASE AS MOST SHORT RANGE MODELS SUCH AS THE HRRR
AND RAP DONT SHOW (AT LEAST WITH MIDDAY AND EARLY AFTN RUNS).
THERE IS AN IMPRESSIVE LOW-850 MB MOISTURE RETURN THIS EVENING-
OVERNIGHT. SEEING 70 DEW PTS ALONG THE SD/ND BORDER INTO THE
ALEXANDRIA AREA WHILE MOST OF OUR FCST AREA HAS DEW PTS IN THE
50S. SO WILL SEE A MOISTURE SURGE TONIGHT AND INSTABILITY INCREASE
IN THE 850 MB LAYER 06Z-12Z PERIOD WHEN A FEW HUNDRED 850 MB CAPE
AVAILABLE. PROBLEM IS LOW LEVEL JET IS VERY WEAK 20 KTS MAYBE. BUT
WILL SIDE WITH CONSITENCY AND KEEP LOW POPS IN BUT HAVE THEM
06Z-12Z....EXTENDING THEM A FEW HOURS PAST 12Z IN LAKE OF THE
WOODS. WEDNESDAY WILL BE MUCH MORE HUMID AND WARM.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 325 PM CDT TUE SEP 1 2015
HOT AND HUMID ON THURSDAY WITH MID 80S EAST TO LOW 90S WEST. WILL
MAINTAIN A LOW THREAT FOR PRECIP LATE THURSDAY NIGHT IN ERN
ND...THEN KEEP CHC POPS ON FRIDAY. UNCERTAIN HOW EVENT WILL PLAY
OUT BUT WILL HAVE SEVERAL SHORT WAVES AND SFC LOWS MOVE NORTHEAST
ALONG A FRONTAL BOUNDARY WHICH WILL BE OVER OR NEAR OUR AREA. EACH
ONE GIVING GOOD CHANCES FOR SHOWERS AND THUNDERSTORMS STARTING
LATE FRIDAY. DAY TO DAY TIMING OF COURSE IS DIFFICULT AT THIS
STAGE.
SATURDAY TO TUESDAY...MODELS IN GOOD AGREEMENT WITH THE GENERAL
500MB SOUTHWEST FLOW ALOFT AND EVOLUTION WITH A CLOSED STRONG SHORT
WAVE MOVING OVER THE NORTHERN PLAINS EARLY NEXT WEEK. AS A RESULT AN
ACTIVE WEATHER PATTERN WITH SEVERAL ROUNDS OF CONVECTIVE ACTIVITY
CAN BE EXPECTED FOR THE REGION OVER THE HOLIDAY WEEKEND.
UNCERTAINTIES EXIST WITH THE TIMING AND PLACEMENT OF THE LEAD WAVE
AND THE STRONGER SHORT WAVE ON MONDAY. CURRENTLY A LEAD WAVE IS
EXPECTED TO BRING A ROUND OF THUNDERSTORMS FRIDAY NIGHT WITH ANOTHER
ROUND SATURDAY NIGHT BEFORE THE THE LIGHTER WRAP AROUND PCPN ON
SUNDAY AFTN AND EARLY MONDAY. GIVEN THE AMPLE MOISTURE IN
PLACE...PWATS APPROACHING 2 INCHES...HEAVY RAIN WILL BE POSSIBLE
WITH ANY STORM. TEMPERATURES WILL BE WARMEST ON SATURDAY WITH LOW
80S IN THE SE HALF OF THE FA AND 70S IN THE NW...HIGHLY INFLUENCED
BY EXPECTED CLOUD COVER. A COOLER...CLOSER TO AVERAGE TEMP REGIME IS
EXPECTED WITH 70S SUNDAY TO TUE BEHIND DEPARTING SHORT WAVE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1249 PM CDT TUE SEP 1 2015
VFR WITH LIGHT SOUTH TO SOUTHWEST WINDS TODAY. TONIGHT
THERE REMAINS A SLIGHT CHC OF A SHOWER OR THUNDERSTORM DEVELOPING
OVERNIGHTACROSS THE NORTHERN HALF OF THE AREA...THOUGH CONFIDENCE IS
LOW AND WILL LEAVE OUT OF THE TAFS FOR NOW.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...RIDDLE
LONG TERM...JK/RIDDLE
AVIATION...JK
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1112 AM EDT TUE SEP 1 2015
.SYNOPSIS...
HOT AND HUMID WEATHER WILL CONTINUE THE RECENT SUMMER ENCORE IN
CENTRAL PENNSYLVANIA...AS THE CALENDER FLIPS TO SEPTEMBER 2015.
THE PRECIPITATION PATTERN SHOULD BE A MAINLY DRY ONE WITH VERY
ISOLATED SHOWERS AND THUNDERSTORMS POSSIBLE THROUGH THE END OF
THE WEEK.
&&
.NEAR TERM /UNTIL 9 PM THIS EVENING/...
FOG/STRATUS ALMOST GONE EXCEPT FOR THE PATCH OVER TIOGA CO. THIS
TOO SHALL PASS. THE CU HAVE ALREADY POPPED UP IN THE LAURELS AND
MID SUSQ/POCONOS. HOWEVER...THE DEEP MIXING TO HAPPEN THIS AFTN
MAY WIPE SOME OF THOSE AWAY DESPITE THE CURRENTLY HIGH SFC
DEWPOINTS. DEWPOINTS MAY DROP BACK INTO THE L60S AND PERHAPS U50S
IN THE HIGHEST ELEVS THIS AFTN. CHC FOR PCPN IS STILL MIGHTY LOW
GIVEN DRY ATMOSPHERE AND WEAK SUBSIDENCE. ONLY THE LAURELS OR NERN
MTNS MAY HAVE A SHOT AT A SPRINKLE.
&&
.SHORT TERM /9 PM THIS EVENING THROUGH THURSDAY NIGHT/...
SOUTH OF THE LOWER LAKES...A SLOW MOVING CLOSED LOW/UPPER LEVEL
WAVE CURRENTLY INVOF IL/IN WILL PUSH SLOWLY EWD ON DAY 1 ALONG OR
JUST NORTH OF THE OH RIVER...REACHING WV BY 12Z WED. THE MODELS
INCLUDING THE HRRR SEEM TO LIKE THE IDEA OF DEVELOPING VERY ISOLD
TO WDLY SCT CONVECTION AHEAD OF THIS FEATURE FROM THE OH VLY TO
THE SPINE OF THE APPALACHIANS ALONG INSTABILITY AXIS. THEREFORE
CUT BACK ON EXTENT OF SCHC POPS OVER SCENTRAL AREAS AND CONFINED
MENTION TO THE SRN/SWRN LAURELS AS PER A CONSENSUS OF THE HI RES
DATA AND GLOBAL GUIDANCE. DESPITE THE CALENDAR SAYING ITS SEPT
1ST...THE MAIN SENSIBLE WEATHER STORY WILL BE THE CONTINUED MID
SUMMER-LIKE HEAT/HUMIDITY WITH DAYTIME HIGHS PUSHING 90F IN THE
MID-LWR SUSQ VLY. PATCHY RADIATIONAL FOG IS ALSO LKLY TO FORM
AGAIN LATER TONIGHT INTO WEDNESDAY MORNING.
THE HIGHEST AREAL AVG POPS /40-50 PCT/ OVER THE NEXT 72 HRS WERE
PAINTED IN FOR DAY 2/WED ACROSS THE SOUTH CENTRAL MTNS...AS THE
AFOREMENTIONED UPPER LEVEL WAVE WEAKENS AND SLIDES ESEWD ACROSS
THE CENTRAL APPALACHIANS. EXPECT ANOTHER VERY WARM AND HUMID DAY
WITH AFTN HIGHS SIMILAR TO TODAY. KEPT SCHC POPS IN FOR DAY 3/THU
ALTHOUGH CONFIDENCE IS LOW GIVEN INCRG MODEL SPREAD AND WEAK/SUBTLE
SHORTWAVE ENERGY UPSTREAM. THE 00Z GFS IS CLEARLY MORE AGGRESSIVE
IN GENERATING CONVECTION ALONG A BACKDOOR FRONT SLIPPING SWD FROM
NYS LATER THURSDAY INTO FRIDAY. OVERALL THE SHORT TERM PERIOD
SHOULD END UP BEING MAINLY DRY AND RELATIVELY HOT FOR THIS TIME OF
YEAR.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AN ANOMALOUS UPPER LEVEL RIDGE IS FORECAST TO DOMINATE THE LARGE
SCALE PATTERN OVER THE NORTHEASTERN CONUS INTO EARLY NEXT
WEEK...WITH HIGH PRESSURE TAKING CONTROL AT THE SFC. THIS PATTERN
SHOULD SUPPORT ABOVE-NORMAL TEMPERATURES AND VERY LIMITED TO
NO RAINFALL ACROSS CENTRAL PA THROUGH THE LABOR DAY WEEKEND.
THE GFS REMAINS MORE BULLISH VS. THE ECMWF WITH CONVECTION ON
FRIDAY. HIGH PRESSURE INITIALLY CENTERED OVER QUEBEC WILL DROP SWD
OVER THE WEEKEND AND BRING SLIGHTLY COOLER AND DRIER/LESS HUMID AIR
INTO THE REGION. NO RISK OF RAIN AGAIN UNTIL PROBABLY NEXT
TUESDAY AS A COLD FRONT APPROACHES FROM THE GREAT LAKES/OH VLY.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
CLEARING SKIES HAVE ALLOWED FOR THE REGIONS WHERE WINDS HAVE
CALMED TO GO MVFR TO IFR. BFD AND IPT WILL CONTINUE TO HAVE LIFR
AND LOWER CONDITIONS THROUGH THE FIRST HALF OF THE MORNING. THE
PATCHY TO DENSE VALLEY FOG WILL SLOWLY DISSIPATE BY 15Z ONCE THE
WEST TO NORTHWEST WINDS MIX DOWN TO THE SFC.. OTHERWISE...HIGH
PRESSURE OFF THE EAST COAST WILL ENSURE WIDESPREAD VFR CONDS AND
LIGHT WINDS ON TUESDAY. ANOTHER ROUND OF VALLEY FOG IS POSSIBLE
TONIGHT.
OUTLOOK...
WED-SAT...PATCHY AM FOG POSS...MAINLY KIPT/KBFD. ISOLD PM TSRA
IMPACTS POSSIBLE...MAINLY W.
&&
.CLIMATE...
PRELIMINARY DATA INDICATES HARRISBURG AND WILLIAMSPORT RECORDED
NEAR-NORMAL TEMPERATURES AND PRECIPITATION FOR THE MONTH OF
AUGUST. MORE DETAILS CAN BE FOUND IN THE MONTHLY CLIMATE
SUMMARIES WHICH WILL BE ISSUED LATER THIS MORNING.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...DANGELO/STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...STEINBUGL
AVIATION...DANGELO/CERU
CLIMATE...
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
807 AM EDT TUE SEP 1 2015
.SYNOPSIS...
HOT AND HUMID WEATHER WILL CONTINUE THE RECENT SUMMER ENCORE IN
CENTRAL PENNSYLVANIA...AS THE CALENDER FLIPS TO SEPTEMBER 2015.
THE PRECIPITATION PATTERN SHOULD BE A MAINLY DRY ONE WITH VERY
ISOLATED SHOWERS AND THUNDERSTORMS POSSIBLE THROUGH THE END OF
THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
8AM UP...
STRATUS OVER THE NORTH BUT THIS SHOULD ERODE OUTSIDE-IN OVER THE
NEXT FEW HOURS. EXPECT SOME SCT CU TO DEVELOP AS THIS PATCH GOES
AWAY - ESP OVER THE NRN MTNS AND LAURELS. DEEP MIXING MAY KEEP THE
COVERAGE SPARSE TO NIL ELSEWHERE. STILL A TINY CHC FOR A SHOWER
IN THE SW...BUT NOT ENOUGH OF ONE TO MENTION AT THIS POINT.
PREV...
LATEST IR STLT LOOP SHOWS THE GREATEST COVERAGE OF RADIATIONAL FOG
OVER THE NORTH CENTRAL ZONES WITH LOCAL VISBYS BELOW 1SM. LOOK FOR
THE FOG TO EXPAND SWD THRU SUNRISE. FOG AND REDUCED VISBYS WILL
CONTINUE TO IMPACT THE AREA THROUGH DAYBREAK BEFORE DISSIPATING BY
MID MORNING. MAY NEED TO ISSUE SPS TO HIGHLIGHT IMPACT ON THE
MORNING COMMUTE TO WORK AND SCHOOL.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
SOUTH OF THE LOWER LAKES...A SLOW MOVING CLOSED LOW/UPPER LEVEL
WAVE CURRENTLY INVOF IL/IN WILL PUSH SLOWLY EWD ON DAY 1 ALONG OR
JUST NORTH OF THE OH RIVER...REACHING WV BY 12Z WED. THE MODELS
INCLUDING THE HRRR SEEM TO LIKE THE IDEA OF DEVELOPING VERY ISOLD
TO WDLY SCT CONVECTION AHEAD OF THIS FEATURE FROM THE OH VLY TO
THE SPINE OF THE APPALACHIANS ALONG INSTABILITY AXIS. THEREFORE
CUT BACK ON EXTENT OF SCHC POPS OVER SCENTRAL AREAS AND CONFINED
MENTION TO THE SRN/SWRN LAURELS AS PER A CONSENSUS OF THE HI RES
DATA AND GLOBAL GUIDANCE. DESPITE THE CALENDAR SAYING ITS SEPT
1ST...THE MAIN SENSIBLE WEATHER STORY WILL BE THE CONTINUED MID
SUMMER-LIKE HEAT/HUMIDITY WITH DAYTIME HIGHS PUSHING 90F IN THE
MID-LWR SUSQ VLY. PATCHY RADIATIONAL FOG IS ALSO LKLY TO FORM
AGAIN LATER TONIGHT INTO WEDNESDAY MORNING.
THE HIGHEST AREAL AVG POPS /40-50 PCT/ OVER THE NEXT 72 HRS WERE
PAINTED IN FOR DAY 2/WED ACROSS THE SOUTH CENTRAL MTNS...AS THE
AFOREMENTIONED UPPER LEVEL WAVE WEAKENS AND SLIDES ESEWD ACROSS
THE CENTRAL APPALACHIANS. EXPECT ANOTHER VERY WARM AND HUMID DAY
WITH AFTN HIGHS SIMILAR TO TODAY. KEPT SCHC POPS IN FOR DAY 3/THU
ALTHOUGH CONFIDENCE IS LOW GIVEN INCRG MODEL SPREAD AND WEAK/SUBTLE
SHORTWAVE ENERGY UPSTREAM. THE 00Z GFS IS CLEARLY MORE AGGRESSIVE
IN GENERATING CONVECTION ALONG A BACKDOOR FRONT SLIPPING SWD FROM
NYS LATER THURSDAY INTO FRIDAY. OVERALL THE SHORT TERM PERIOD
SHOULD END UP BEING MAINLY DRY AND RELATIVELY HOT FOR THIS TIME OF
YEAR.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AN ANOMALOUS UPPER LEVEL RIDGE IS FORECAST TO DOMINATE THE LARGE
SCALE PATTERN OVER THE NORTHEASTERN CONUS INTO EARLY NEXT
WEEK...WITH HIGH PRESSURE TAKING CONTROL AT THE SFC. THIS PATTERN
SHOULD SUPPORT ABOVE-NORMAL TEMPERATURES AND VERY LIMITED TO
NO RAINFALL ACROSS CENTRAL PA THROUGH THE LABOR DAY WEEKEND.
THE GFS REMAINS MORE BULLISH VS. THE ECMWF WITH CONVECTION ON
FRIDAY. HIGH PRESSURE INITIALLY CENTERED OVER QUEBEC WILL DROP SWD
OVER THE WEEKEND AND BRING SLIGHTLY COOLER AND DRIER/LESS HUMID AIR
INTO THE REGION. NO RISK OF RAIN AGAIN UNTIL PROBABLY NEXT
TUESDAY AS A COLD FRONT APPROACHES FROM THE GREAT LAKES/OH VLY.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
CLEARING SKIES HAVE ALLOWED FOR THE REGIONS WHERE WINDS HAVE
CALMED TO GO MVFR TO IFR. BFD AND IPT WILL CONTINUE TO HAVE LIFR
AND LOWER CONDITIONS THROUGH THE FIRST HALF OF THE MORNING. THE
PATCHY TO DENSE VALLEY FOG WILL SLOWLY DISSIPATE BY 15Z ONCE THE
WEST TO NORTHWEST WINDS MIX DOWN TO THE SFC.. OTHERWISE...HIGH
PRESSURE OFF THE EAST COAST WILL ENSURE WIDESPREAD VFR CONDS AND
LIGHT WINDS ON TUESDAY. ANOTHER ROUND OF VALLEY FOG IS POSSIBLE
TONIGHT.
OUTLOOK...
WED-SAT...PATCHY AM FOG POSS...MAINLY KIPT/KBFD. ISOLD PM TSRA
IMPACTS POSSIBLE...MAINLY W.
&&
.CLIMATE...
PRELIMINARY DATA INDICATES HARRISBURG AND WILLIAMSPORT RECORDED
NEAR-NORMAL TEMPERATURES AND PRECIPITATION FOR THE MONTH OF
AUGUST. MORE DETAILS CAN BE FOUND IN THE MONTHLY CLIMATE
SUMMARIES WHICH WILL BE ISSUED LATER THIS MORNING.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...DANGELO/STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...STEINBUGL
AVIATION...FITZGERALD/CERU
CLIMATE...
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
757 AM EDT TUE SEP 1 2015
.SYNOPSIS...
HOT AND HUMID WEATHER WILL CONTINUE THE RECENT SUMMER ENCORE IN
CENTRAL PENNSYLVANIA...AS THE CALENDER FLIPS TO SEPTEMBER 2015.
THE PRECIPITATION PATTERN SHOULD BE A MAINLY DRY ONE WITH VERY
ISOLATED SHOWERS AND THUNDERSTORMS POSSIBLE THROUGH THE END OF
THE WEEK.
&&
.NEAR TERM /UNTIL 10 AM THIS MORNING/...
LATEST IR STLT LOOP SHOWS THE GREATEST COVERAGE OF RADIATIONAL FOG
OVER THE NORTH CENTRAL ZONES WITH LOCAL VISBYS BELOW 1SM. LOOK FOR
THE FOG TO EXPAND SWD THRU SUNRISE. FOG AND REDUCED VISBYS WILL
CONTINUE TO IMPACT THE AREA THROUGH DAYBREAK BEFORE DISSIPATING BY
MID MORNING. MAY NEED TO ISSUE SPS TO HIGHLIGHT IMPACT ON THE
MORNING COMMUTE TO WORK AND SCHOOL.
&&
.SHORT TERM /10 AM THIS MORNING THROUGH THURSDAY NIGHT/...
SOUTH OF THE LOWER LAKES...A SLOW MOVING CLOSED LOW/UPPER LEVEL
WAVE CURRENTLY INVOF IL/IN WILL PUSH SLOWLY EWD ON DAY 1 ALONG OR
JUST NORTH OF THE OH RIVER...REACHING WV BY 12Z WED. THE MODELS
INCLUDING THE HRRR SEEM TO LIKE THE IDEA OF DEVELOPING VERY ISOLD
TO WDLY SCT CONVECTION AHEAD OF THIS FEATURE FROM THE OH VLY TO
THE SPINE OF THE APPALACHIANS ALONG INSTABILITY AXIS. THEREFORE
CUT BACK ON EXTENT OF SCHC POPS OVER SCENTRAL AREAS AND CONFINED
MENTION TO THE SRN/SWRN LAURELS AS PER A CONSENSUS OF THE HI RES
DATA AND GLOBAL GUIDANCE. DESPITE THE CALENDAR SAYING ITS SEPT
1ST...THE MAIN SENSIBLE WEATHER STORY WILL BE THE CONTINUED MID
SUMMER-LIKE HEAT/HUMIDITY WITH DAYTIME HIGHS PUSHING 90F IN THE
MID-LWR SUSQ VLY. PATCHY RADIATIONAL FOG IS ALSO LKLY TO FORM
AGAIN LATER TONIGHT INTO WEDNESDAY MORNING.
THE HIGHEST AREAL AVG POPS /40-50 PCT/ OVER THE NEXT 72 HRS WERE
PAINTED IN FOR DAY 2/WED ACROSS THE SOUTH CENTRAL MTNS...AS THE
AFOREMENTIONED UPPER LEVEL WAVE WEAKENS AND SLIDES ESEWD ACROSS
THE CENTRAL APPALACHIANS. EXPECT ANOTHER VERY WARM AND HUMID DAY
WITH AFTN HIGHS SIMILAR TO TODAY. KEPT SCHC POPS IN FOR DAY 3/THU
ALTHOUGH CONFIDENCE IS LOW GIVEN INCRG MODEL SPREAD AND WEAK/SUBTLE
SHORTWAVE ENERGY UPSTREAM. THE 00Z GFS IS CLEARLY MORE AGGRESSIVE
IN GENERATING CONVECTION ALONG A BACKDOOR FRONT SLIPPING SWD FROM
NYS LATER THURSDAY INTO FRIDAY. OVERALL THE SHORT TERM PERIOD
SHOULD END UP BEING MAINLY DRY AND RELATIVELY HOT FOR THIS TIME OF
YEAR.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AN ANOMALOUS UPPER LEVEL RIDGE IS FORECAST TO DOMINATE THE LARGE
SCALE PATTERN OVER THE NORTHEASTERN CONUS INTO EARLY NEXT
WEEK...WITH HIGH PRESSURE TAKING CONTROL AT THE SFC. THIS PATTERN
SHOULD SUPPORT ABOVE-NORMAL TEMPERATURES AND VERY LIMITED TO
NO RAINFALL ACROSS CENTRAL PA THROUGH THE LABOR DAY WEEKEND.
THE GFS REMAINS MORE BULLISH VS. THE ECMWF WITH CONVECTION ON
FRIDAY. HIGH PRESSURE INITIALLY CENTERED OVER QUEBEC WILL DROP SWD
OVER THE WEEKEND AND BRING SLIGHTLY COOLER AND DRIER/LESS HUMID AIR
INTO THE REGION. NO RISK OF RAIN AGAIN UNTIL PROBABLY NEXT
TUESDAY AS A COLD FRONT APPROACHES FROM THE GREAT LAKES/OH VLY.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
CLEARING SKIES HAVE ALLOWED FOR THE REGIONS WHERE WINDS HAVE
CALMED TO GO MVFR TO IFR. BFD AND IPT WILL CONTINUE TO HAVE LIFR
AND LOWER CONDITIONS THROUGH THE FIRST HALF OF THE MORNING. THE
PATCHY TO DENSE VALLEY FOG WILL SLOWLY DISSIPATE BY 15Z ONCE THE
WEST TO NORTHWEST WINDS MIX DOWN TO THE SFC.. OTHERWISE...HIGH
PRESSURE OFF THE EAST COAST WILL ENSURE WIDESPREAD VFR CONDS AND
LIGHT WINDS ON TUESDAY. ANOTHER ROUND OF VALLEY FOG IS POSSIBLE
TONIGHT.
OUTLOOK...
WED-SAT...PATCHY AM FOG POSS...MAINLY KIPT/KBFD. ISOLD PM TSRA
IMPACTS POSSIBLE...MAINLY W.
&&
.CLIMATE...
PRELIMINARY DATA INDICATES HARRISBURG AND WILLIAMSPORT RECORDED
NEAR-NORMAL TEMPERATURES AND PRECIPITATION FOR THE MONTH OF
AUGUST. MORE DETAILS CAN BE FOUND IN THE MONTHLY CLIMATE
SUMMARIES WHICH WILL BE ISSUED LATER THIS MORNING.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...STEINBUGL
AVIATION...FITZGERALD/CERU
CLIMATE...
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
440 AM EDT TUE SEP 1 2015
.SYNOPSIS...
HOT AND HUMID WEATHER WILL CONTINUE THE RECENT SUMMER ENCORE IN
CENTRAL PENNSYLVANIA...AS THE CALENDER FLIPS TO SEPTEMBER 2015.
THE PRECIPITATION PATTERN SHOULD BE A MAINLY DRY ONE WITH VERY
ISOLATED SHOWERS AND THUNDERSTORMS POSSIBLE THROUGH THE END OF
THE WEEK.
&&
.NEAR TERM /UNTIL 10 AM THIS MORNING/...
LATEST IR STLT LOOP SHOWS THE GREATEST COVERAGE OF RADIATIONAL FOG
OVER THE NORTH CENTRAL ZONES WITH LOCAL VISBYS BELOW 1SM. LOOK FOR
THE FOG TO EXPAND SWD THRU SUNRISE. FOG AND REDUCED VISBYS WILL
CONTINUE TO IMPACT THE AREA THROUGH DAYBREAK BEFORE DISSIPATING BY
MID MORNING. MAY NEED TO ISSUE SPS TO HIGHLIGHT IMPACT ON THE
MORNING COMMUTE TO WORK AND SCHOOL.
&&
.SHORT TERM /10 AM THIS MORNING THROUGH THURSDAY NIGHT/...
SOUTH OF THE LOWER LAKES...A SLOW MOVING CLOSED LOW/UPPER LEVEL
WAVE CURRENTLY INVOF IL/IN WILL PUSH SLOWLY EWD ON DAY 1 ALONG OR
JUST NORTH OF THE OH RIVER...REACHING WV BY 12Z WED. THE MODELS
INCLUDING THE HRRR SEEM TO LIKE THE IDEA OF DEVELOPING VERY ISOLD
TO WDLY SCT CONVECTION AHEAD OF THIS FEATURE FROM THE OH VLY TO
THE SPINE OF THE APPALACHIANS ALONG INSTABILITY AXIS. THEREFORE
CUT BACK ON EXTENT OF SCHC POPS OVER SCENTRAL AREAS AND CONFINED
MENTION TO THE SRN/SWRN LAURELS AS PER A CONSENSUS OF THE HI RES
DATA AND GLOBAL GUIDANCE. DESPITE THE CALENDAR SAYING ITS SEPT
1ST...THE MAIN SENSIBLE WEATHER STORY WILL BE THE CONTINUED MID
SUMMER-LIKE HEAT/HUMIDITY WITH DAYTIME HIGHS PUSHING 90F IN THE
MID-LWR SUSQ VLY. PATCHY RADIATIONAL FOG IS ALSO LKLY TO FORM
AGAIN LATER TONIGHT INTO WEDNESDAY MORNING.
THE HIGHEST AREAL AVG POPS /40-50 PCT/ OVER THE NEXT 72 HRS WERE
PAINTED IN FOR DAY 2/WED ACROSS THE SOUTH CENTRAL MTNS...AS THE
AFOREMENTIONED UPPER LEVEL WAVE WEAKENS AND SLIDES ESEWD ACROSS
THE CENTRAL APPALACHIANS. EXPECT ANOTHER VERY WARM AND HUMID DAY
WITH AFTN HIGHS SIMILAR TO TODAY. KEPT SCHC POPS IN FOR DAY 3/THU
ALTHOUGH CONFIDENCE IS LOW GIVEN INCRG MODEL SPREAD AND WEAK/SUBTLE
SHORTWAVE ENERGY UPSTREAM. THE 00Z GFS IS CLEARLY MORE AGGRESSIVE
IN GENERATING CONVECTION ALONG A BACKDOOR FRONT SLIPPING SWD FROM
NYS LATER THURSDAY INTO FRIDAY. OVERALL THE SHORT TERM PERIOD
SHOULD END UP BEING MAINLY DRY AND RELATIVELY HOT FOR THIS TIME OF
YEAR.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AN ANOMALOUS UPPER LEVEL RIDGE IS FORECAST TO DOMINATE THE LARGE
SCALE PATTERN OVER THE NORTHEASTERN CONUS INTO EARLY NEXT
WEEK...WITH HIGH PRESSURE TAKING CONTROL AT THE SFC. THIS PATTERN
SHOULD SUPPORT ABOVE-NORMAL TEMPERATURES AND VERY LIMITED TO
NO RAINFALL ACROSS CENTRAL PA THROUGH THE LABOR DAY WEEKEND.
THE GFS REMAINS MORE BULLISH VS. THE ECMWF WITH CONVECTION ON
FRIDAY. HIGH PRESSURE INITIALLY CENTERED OVER QUEBEC WILL DROP SWD
OVER THE WEEKEND AND BRING SLIGHTLY COOLER AND DRIER/LESS HUMID AIR
INTO THE REGION. NO RISK OF RAIN AGAIN UNTIL PROBABLY NEXT
TUESDAY AS A COLD FRONT APPROACHES FROM THE GREAT LAKES/OH VLY.
&&
.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
CLEARING SKIES HAVE ALLOWED FOR THE REGIONS WHERE WINDS HAVE
CALMED TO GO MVFR TO IFR. BFD AND IPT WILL SEE THE MOST INTENSE
RESTRICTIONS WHERE BOTH LOCATIONS HAVE OR CURRENTLY ARE SEEING
IFR AND LOWER. IPT WILL SEE CONDITIONS VARY FOR THE NEXT FEW
HOURS BEFORE THE PATCHY FOG BECOMES DENSE ENOUGH TO PERSIST.
UNV...AOO...LNS AND MDT SHOULD SEE MVFR CIGS AND VSBYS. IF ANY OF
THESE LOCATIONS DECOUPLE WITH CALM WINDS FOR 2 OR MORE HOURS
EXPECT IFR CIGS AND VSBYS TO DEVELOP. THIS IS A MAIN CONCERN
BETWEEN 09Z TO 13Z. ANY AM FOG SHOULD BURN OFF BY BTWN 12Z-14Z.
OTHERWISE...HIGH PRESSURE OFF THE EAST COAST WILL ENSURE
WIDESPREAD VFR CONDS AND LIGHT WINDS ON TUESDAY. THERE IS JUST A
SLIGHT CHC OF A PM SHRA/TSRA IN VICINITY OF KJST.
OUTLOOK...
WED-SAT...PATCHY AM FOG POSS...MAINLY KIPT/KBFD. ISOLD PM TSRA
IMPACTS POSSIBLE...MAINLY W.
&&
.CLIMATE...
PRELIMINARY DATA INDICATES HARRISBURG AND WILLIAMSPORT RECORDED
NEAR-NORMAL TEMPERATUERS AND PRECIPITATION FOR THE MONTH OF
AUGUST. MORE DETAILS CAN BE FOUND IN THE MONTHLY CLIMATE
SUMMARIES WHICH WILL BE ISSUED LATER THIS MORNING.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...STEINBUGL
AVIATION...FITZGERALD/CERU
CLIMATE...STEINBUGL
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1244 PM CDT TUE SEP 1 2015
.AVIATION...
/18Z TAFS/
A CLUSTER OF MODERATE TO HEAVY SHOWERS IS TO THE EAST OF KAUS AND
EXPECTED TO REMAIN TO THE EAST. HOWEVER...ISOLATED SHOWERS ARE
EXPECTED TO OCCUR AT AND NEAR KAUS THROUGH 20Z. NO SEEING
LIGHTNING WITH THESE STORMS AND OPTED OF KEEPING OUT TS FOR NOW.
WILL KEEP CLOSELY MONITORING RADAR TRENDS FOR ANY AMENDMENTS.
OTHERWISE...VFR CONDITIONS ARE EXPECTED ACROSS KSAT...KSSF AND
KDRT THROUGH LATE TONIGHT. CIGS WILL LOWER TO MVFR CONDITIONS
OVERNIGHT FROM AROUND 09Z TO 15Z WED WITH THE EXCEPTION OF VFR AT
KDRT. MORE SHOWER ACTIVITY IS FORECAST FOR WEDNESDAY...BUT MAINLY
ACROSS THE COASTAL PLAINS AND AWAY FROM THE AREA SITES. SOUTHERLY
WINDS WILL PREVAIL THROUGH THE PERIOD AND AVERAGING FROM 6 TO 12
KNOTS DURING THE DAYTIME AND LIGHT TO CALM OVERNIGHT.
&&
.PREV DISCUSSION... /ISSUED 857 AM CDT TUE SEP 1 2015/
UPDATE...
TROPICAL MOISTURE IS SPREADING INLAND AND SHOWERS HAVE MOVED A BIT
FARTHER TO THE NORTHWEST SOONER THAN PREVIOUSLY ANTICIPATED. HAVE
UPDATED TO REFLECT THIS CHANGE. COVERAGE SHOULD REMAIN ISOLATED
THROUGH THE REST OF THE MORNING. ALSO UPDATED HOURLY GRIDS TO
ACCOUNT FOR OBSERVATIONAL TRENDS.
PREV DISCUSSION... /ISSUED 703 AM CDT TUE SEP 1 2015/
AVIATION.../12Z TAFS/
SAT/SSF CIGS HAVE LOWERED TO IFR WHILE AUS HAS REMAINED LOW MVFR.
THE I-35 SITES SHOULD GRADUALLY RECOVER TO BKNO20 BY 15Z AND
IMPROVE TO VFR BY 16Z. MOIST E-SE FLOW UP THE RIO GRANDE WILL
LIKELY BRING IN BORDERLINE LOW MVFR CONDITIONS TO DRT BETWEEN
12-15Z...BUT CONFIDENCE IS LOW SO HAVE GONE SCT010 THERE FOR NOW.
BIGGEST FORECAST ISSUE IS WHETHER OR NOT THE I-35 TAF SITES WILL
HAVE SHRA/TSRA THIS AFTERNOON. HI-RES MODELS ARE FINALLY BEGINNING
TO INITIALIZE THE STORM COMPLEX MOVING NE ALONG THE GULF COAST.
6Z TX TECH WRF APPEARED TO HAVE THE BEST HANDLE ON THIS
SYSTEM...SO LEANED TOWARDS THAT IN ADDING IN VCSH FOR SAT/SSF/AUS
FROM 19-01Z. HOWEVER...RAP SUGGESTS VCSH IS POSSIBLE AS EARLY AS
15Z WHILE THE HRRR HAS VERY LITTLE COVERAGE. CONSIDERING THE
COMPLEX IN THE GULF WILL LIKELY PRECLUDE THE DEVELOPMENT OF AN
ORGANIZED SEA BREEZE TODAY TO PROVIDE A FOCUS FOR
CONVECTION...CONFIDENCE FOR THIS FORECAST IS RELATIVELY LOW.
PREV DISCUSSION... /ISSUED 401 AM CDT TUE SEP 1 2015/
SHORT TERM (TODAY THROUGH WEDNESDAY)...
THE LATEST WATER VAPOR SATELLITE LOOP SHOWS AN UPPER TROUGH OVER
CENTRAL AND EASTERN TEXAS. RADAR DATA ALONG WITH THE LIGHTNING
DETECTION NETWORK SHOW CONVECTION CONTINUES EARLY THIS MORNING
ALONG THE TEXAS COAST. THE UPPER AIR PATTERN WILL CHANGE LITTLE
THROUGH WEDNESDAY. THIS WILL RESULT IN RAIN CHANCES FAVORED FOR
AREAS GENERALLY ALONG AND EAST OF A BURNET TO HONDO LINE. MOISTURE
LEVELS WILL BE HIGHEST NEAR THE TEXAS COAST AND WITH THE SEA
BREEZE PROVIDING SOME EXTRA LIFT...THE BEST CHANCES FOR RAIN WILL
BE CONFINED TO THE COASTAL PLAINS. FARTHER WEST...MOISTURE LEVELS
DECREASE. HOWEVER...GIVEN MID-LEVEL SHORTWAVE TROUGHS EMBEDDED IN
THE UPPER TROUGH WE STILL EXPECT SOME ISOLATED CONVECTION DURING
THE AFTERNOON AND EVENING HOURS. NO SIGNIFICANT CHANGES IN
TEMPERATURES ARE EXPECTED WITH HIGHS IN THE 90S AND LOWS IN THE
UPPER 60S AND 70S.
LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY)...
THE UPPER AIR PATTERN SLOWLY BEGINS TO CHANGE MID-WEEK AS UPPER
LEVEL RIDGING BUILDS IN FROM THE WEST...FORCING THE ABOVE
MENTIONED UPPER TROUGH EASTWARD. THE UPPER RIDGE REMAINS DOMINANT
THROUGH THE REMAINDER OF THE WEEK ACROSS SOUTH CENTRAL TEXAS. THIS
WILL KEEP RAIN CHANCES FAVORED EAST OF I-35 FOR THE REMAINDER OF
THIS WEEK. THE BEST CHANCE FOR RAIN WILL BE NEAR THE COASTAL
PLAINS WHERE SLIGHTLY DEEPER MOISTURE WILL INTERACT WITH DAYTIME
HEATING AND THE SEA BREEZE RESULTING IN ISOLATED TO SCATTERED
CONVECTION. TEMPERATURES THROUGH THE REMAINDER OF THE WEEK REMAIN
NEAR SEASONAL NORMALS.
EARLY NEXT WEEK...THE OPERATIONAL GFS SHOWS AN UPPER TROUGH
DEVELOPING OVER THE NORTHERN GULF OF MEXICO. THE ECMWF OPERATIONAL
AND ENSEMBLE SOLUTIONS ALSO SHOW THIS TROUGH...BUT KEEP IT FARTHER
EAST ACROSS THE SOUTHEASTERN U.S. CAN/T SEE ANY SIGNIFICANT REASON
TO DEVIATE FROM THE CURRENT FORECAST...WHICH CALLS FOR SEASONAL
TEMPERATURES ALONG WITH A LOW CHANCE FOR CONVECTION NEAR THE
COASTAL PLAINS.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 73 94 73 94 74 / 20 20 - 10 10
AUSTIN BERGSTROM INTL AIRPORT 71 93 70 93 71 / 20 20 - 10 10
NEW BRAUNFELS MUNI AIRPORT 73 94 73 94 74 / 20 20 10 10 10
BURNET MUNI AIRPORT 72 92 71 93 72 / 10 10 0 10 -
DEL RIO INTL AIRPORT 75 97 75 96 76 / 0 - 0 0 -
GEORGETOWN MUNI AIRPORT 72 93 72 93 73 / 20 20 0 10 10
HONDO MUNI AIRPORT 71 95 71 95 71 / 20 10 10 10 10
SAN MARCOS MUNI AIRPORT 72 93 72 93 73 / 20 20 10 10 10
LA GRANGE - FAYETTE REGIONAL 73 93 71 93 73 / 40 30 10 30 10
SAN ANTONIO INTL AIRPORT 75 95 75 94 76 / 20 20 10 10 10
STINSON MUNI AIRPORT 74 95 73 95 75 / 20 20 10 10 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...17
SYNOPTIC/GRIDS...05
PUBLIC SERVICE/DATA COLLECTION...33
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
857 AM CDT TUE SEP 1 2015
.UPDATE...
TROPICAL MOISTURE IS SPREADING INLAND AND SHOWERS HAVE MOVED A BIT
FARTHER TO THE NORTHWEST SOONER THAN PREVIOUSLY ANTICIPATED. HAVE
UPDATED TO REFLECT THIS CHANGE. COVERAGE SHOULD REMAIN ISOLATED
THROUGH THE REST OF THE MORNING. ALSO UPDATED HOURLY GRIDS TO
ACCOUNT FOR OBSERVATIONAL TRENDS.
&&
.PREV DISCUSSION... /ISSUED 703 AM CDT TUE SEP 1 2015/
AVIATION.../12Z TAFS/
SAT/SSF CIGS HAVE LOWERED TO IFR WHILE AUS HAS REMAINED LOW MVFR.
THE I-35 SITES SHOULD GRADUALLY RECOVER TO BKNO20 BY 15Z AND
IMPROVE TO VFR BY 16Z. MOIST E-SE FLOW UP THE RIO GRANDE WILL
LIKELY BRING IN BORDERLINE LOW MVFR CONDITIONS TO DRT BETWEEN
12-15Z...BUT CONFIDENCE IS LOW SO HAVE GONE SCT010 THERE FOR NOW.
BIGGEST FORECAST ISSUE IS WHETHER OR NOT THE I-35 TAF SITES WILL
HAVE SHRA/TSRA THIS AFTERNOON. HI-RES MODELS ARE FINALLY BEGINNING
TO INITIALIZE THE STORM COMPLEX MOVING NE ALONG THE GULF COAST.
6Z TX TECH WRF APPEARED TO HAVE THE BEST HANDLE ON THIS
SYSTEM...SO LEANED TOWARDS THAT IN ADDING IN VCSH FOR SAT/SSF/AUS
FROM 19-01Z. HOWEVER...RAP SUGGESTS VCSH IS POSSIBLE AS EARLY AS
15Z WHILE THE HRRR HAS VERY LITTLE COVERAGE. CONSIDERING THE
COMPLEX IN THE GULF WILL LIKELY PRECLUDE THE DEVELOPMENT OF AN
ORGANIZED SEA BREEZE TODAY TO PROVIDE A FOCUS FOR
CONVECTION...CONFIDENCE FOR THIS FORECAST IS RELATIVELY LOW.
PREV DISCUSSION... /ISSUED 401 AM CDT TUE SEP 1 2015/
SHORT TERM (TODAY THROUGH WEDNESDAY)...
THE LATEST WATER VAPOR SATELLITE LOOP SHOWS AN UPPER TROUGH OVER
CENTRAL AND EASTERN TEXAS. RADAR DATA ALONG WITH THE LIGHTNING
DETECTION NETWORK SHOW CONVECTION CONTINUES EARLY THIS MORNING
ALONG THE TEXAS COAST. THE UPPER AIR PATTERN WILL CHANGE LITTLE
THROUGH WEDNESDAY. THIS WILL RESULT IN RAIN CHANCES FAVORED FOR
AREAS GENERALLY ALONG AND EAST OF A BURNET TO HONDO LINE. MOISTURE
LEVELS WILL BE HIGHEST NEAR THE TEXAS COAST AND WITH THE SEA
BREEZE PROVIDING SOME EXTRA LIFT...THE BEST CHANCES FOR RAIN WILL
BE CONFINED TO THE COASTAL PLAINS. FARTHER WEST...MOISTURE LEVELS
DECREASE. HOWEVER...GIVEN MID-LEVEL SHORTWAVE TROUGHS EMBEDDED IN
THE UPPER TROUGH WE STILL EXPECT SOME ISOLATED CONVECTION DURING
THE AFTERNOON AND EVENING HOURS. NO SIGNIFICANT CHANGES IN
TEMPERATURES ARE EXPECTED WITH HIGHS IN THE 90S AND LOWS IN THE
UPPER 60S AND 70S.
LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY)...
THE UPPER AIR PATTERN SLOWLY BEGINS TO CHANGE MID-WEEK AS UPPER
LEVEL RIDGING BUILDS IN FROM THE WEST...FORCING THE ABOVE
MENTIONED UPPER TROUGH EASTWARD. THE UPPER RIDGE REMAINS DOMINANT
THROUGH THE REMAINDER OF THE WEEK ACROSS SOUTH CENTRAL TEXAS. THIS
WILL KEEP RAIN CHANCES FAVORED EAST OF I-35 FOR THE REMAINDER OF
THIS WEEK. THE BEST CHANCE FOR RAIN WILL BE NEAR THE COASTAL
PLAINS WHERE SLIGHTLY DEEPER MOISTURE WILL INTERACT WITH DAYTIME
HEATING AND THE SEA BREEZE RESULTING IN ISOLATED TO SCATTERED
CONVECTION. TEMPERATURES THROUGH THE REMAINDER OF THE WEEK REMAIN
NEAR SEASONAL NORMALS.
EARLY NEXT WEEK...THE OPERATIONAL GFS SHOWS AN UPPER TROUGH
DEVELOPING OVER THE NORTHERN GULF OF MEXICO. THE ECMWF OPERATIONAL
AND ENSEMBLE SOLUTIONS ALSO SHOW THIS TROUGH...BUT KEEP IT FARTHER
EAST ACROSS THE SOUTHEASTERN U.S. CAN/T SEE ANY SIGNIFICANT REASON
TO DEVIATE FROM THE CURRENT FORECAST...WHICH CALLS FOR SEASONAL
TEMPERATURES ALONG WITH A LOW CHANCE FOR CONVECTION NEAR THE
COASTAL PLAINS.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 95 73 94 73 94 / 20 20 20 - 10
AUSTIN BERGSTROM INTL AIRPORT 93 71 93 70 93 / 20 20 20 - 10
NEW BRAUNFELS MUNI AIRPORT 95 73 94 73 94 / 20 20 20 10 10
BURNET MUNI AIRPORT 93 72 92 71 93 / 10 10 10 0 10
DEL RIO INTL AIRPORT 97 75 97 75 96 / - 0 - 0 0
GEORGETOWN MUNI AIRPORT 93 72 93 72 93 / 20 20 20 0 10
HONDO MUNI AIRPORT 95 71 95 71 95 / 20 20 10 10 10
SAN MARCOS MUNI AIRPORT 93 72 93 72 93 / 20 20 20 10 10
LA GRANGE - FAYETTE REGIONAL 93 73 93 71 93 / 40 40 30 10 30
SAN ANTONIO INTL AIRPORT 93 75 95 75 94 / 20 20 20 10 10
STINSON MUNI AIRPORT 94 74 95 73 95 / 20 20 20 10 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...17
SYNOPTIC/GRIDS...05
PUBLIC SERVICE/DATA COLLECTION...33
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
703 AM CDT TUE SEP 1 2015
.AVIATION.../12Z TAFS/
SAT/SSF CIGS HAVE LOWERED TO IFR WHILE AUS HAS REMAINED LOW MVFR.
THE I-35 SITES SHOULD GRADUALLY RECOVER TO BKNO20 BY 15Z AND
IMPROVE TO VFR BY 16Z. MOIST E-SE FLOW UP THE RIO GRANDE WILL
LIKELY BRING IN BORDERLINE LOW MVFR CONDITIONS TO DRT BETWEEN
12-15Z...BUT CONFIDENCE IS LOW SO HAVE GONE SCT010 THERE FOR NOW.
BIGGEST FORECAST ISSUE IS WHETHER OR NOT THE I-35 TAF SITES WILL
HAVE SHRA/TSRA THIS AFTERNOON. HI-RES MODELS ARE FINALLY BEGINNING
TO INITIALIZE THE STORM COMPLEX MOVING NE ALONG THE GULF COAST.
6Z TX TCH WRF APPEARED TO HAVE THE BEST HANDLE ON THIS SYSTEM...SO
LEANED TOWARDS THAT IN ADDING IN VCSH FOR SAT/SSF/AUS FROM
19-01Z. HOWEVER...RAP SUGGESTS VCSH IS POSSIBLE AS EARLY AS 15Z
WHILE THE HRRR HAS VERY LITTLE COVERAGE. CONSIDERIG THE COMPLEX IN
THE GULF WILL LIKELY PRECLUDE THE DEVELOPMENT OF AN ORGANIZED SEA
BREEZE TODAY TO PROVIDE A FOCUS FOR CONVECTION...CONFIDENCE FOR
THIS FORECAST IS RELATIVELY LOW.
&&
.PREV DISCUSSION... /ISSUED 401 AM CDT TUE SEP 1 2015/
SHORT TERM (TODAY THROUGH WEDNESDAY)...
THE LATEST WATER VAPOR SATELLITE LOOP SHOWS AN UPPER TROUGH OVER
CENTRAL AND EASTERN TEXAS. RADAR DATA ALONG WITH THE LIGHTNING
DETECTION NETWORK SHOW CONVECTION CONTINUES EARLY THIS MORNING
ALONG THE TEXAS COAST. THE UPPER AIR PATTERN WILL CHANGE LITTLE
THROUGH WEDNESDAY. THIS WILL RESULT IN RAIN CHANCES FAVORED FOR
AREAS GENERALLY ALONG AND EAST OF A BURNET TO HONDO LINE. MOISTURE
LEVELS WILL BE HIGHEST NEAR THE TEXAS COAST AND WITH THE SEA
BREEZE PROVIDING SOME EXTRA LIFT...THE BEST CHANCES FOR RAIN WILL
BE CONFINED TO THE COASTAL PLAINS. FARTHER WEST...MOISTURE LEVELS
DECREASE. HOWEVER...GIVEN MID-LEVEL SHORTWAVE TROUGHS EMBEDDED IN
THE UPPER TROUGH WE STILL EXPECT SOME ISOLATED CONVECTION DURING
THE AFTERNOON AND EVENING HOURS. NO SIGNIFICANT CHANGES IN
TEMPERATURES ARE EXPECTED WITH HIGHS IN THE 90S AND LOWS IN THE
UPPER 60S AND 70S.
LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY)...
THE UPPER AIR PATTERN SLOWLY BEGINS TO CHANGE MID-WEEK AS UPPER
LEVEL RIDGING BUILDS IN FROM THE WEST...FORCING THE ABOVE
MENTIONED UPPER TROUGH EASTWARD. THE UPPER RIDGE REMAINS DOMINANT
THROUGH THE REMAINDER OF THE WEEK ACROSS SOUTH CENTRAL TEXAS. THIS
WILL KEEP RAIN CHANCES FAVORED EAST OF I-35 FOR THE REMAINDER OF
THIS WEEK. THE BEST CHANCE FOR RAIN WILL BE NEAR THE COASTAL
PLAINS WHERE SLIGHTLY DEEPER MOISTURE WILL INTERACT WITH DAYTIME
HEATING AND THE SEA BREEZE RESULTING IN ISOLATED TO SCATTERED
CONVECTION. TEMPERATURES THROUGH THE REMAINDER OF THE WEEK REMAIN
NEAR SEASONAL NORMALS.
EARLY NEXT WEEK...THE OPERATIONAL GFS SHOWS AN UPPER TROUGH
DEVELOPING OVER THE NORTHERN GULF OF MEXICO. THE ECMWF OPERATIONAL
AND ENSEMBLE SOLUTIONS ALSO SHOW THIS TROUGH...BUT KEEP IT FARTHER
EAST ACROSS THE SOUTHEASTERN U.S. CAN/T SEE ANY SIGNIFICANT REASON
TO DEVIATE FROM THE CURRENT FORECAST...WHICH CALLS FOR SEASONAL
TEMPERATURES ALONG WITH A LOW CHANCE FOR CONVECTION NEAR THE
COASTAL PLAINS.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 95 73 94 73 94 / 20 20 20 - 10
AUSTIN BERGSTROM INTL AIRPORT 93 71 93 70 93 / 20 20 20 - 10
NEW BRAUNFELS MUNI AIRPORT 95 73 94 73 94 / 20 20 20 10 10
BURNET MUNI AIRPORT 93 72 92 71 93 / 10 10 10 0 10
DEL RIO INTL AIRPORT 97 75 97 75 96 / - 0 - 0 0
GEORGETOWN MUNI AIRPORT 93 72 93 72 93 / 20 20 20 0 10
HONDO MUNI AIRPORT 95 71 95 71 95 / 20 20 10 10 10
SAN MARCOS MUNI AIRPORT 93 72 93 72 93 / 20 20 20 10 10
LA GRANGE - FAYETTE REGIONAL 93 73 93 71 93 / 40 40 30 10 30
SAN ANTONIO INTL AIRPORT 93 75 95 75 94 / 20 20 20 10 10
STINSON MUNI AIRPORT 94 74 95 73 95 / 20 20 20 10 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...LH
SYNOPTIC/GRIDS...24
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
102 AM CDT TUE SEP 1 2015
.AVIATION.../06Z TAFS/
CIGS HAVE ALREADY LOWERED TO MVFR AT SAT/SSF...AND EXPECT THE SAME
TO OCCUR AT AUS AND DRT BETWEEN 9-10Z. CIGS SHOULD RECOVER TO VFR
BY 16Z AT ALL SITES...BUT CONFIDENCE IS LOW DUE TO CONVECTION THAT
IS DEVELOPING ALONG THE GULF COAST NEAR CRP. NONE OF THE HI-RES
MODELS ACCURATELY DEPICTED THIS EARLY ONSET OF TSRA...WITH ONLY
THE RAP SHOWING SOME SEMBLANCE OF IT. FURTHER...IT APPEARS THE
MIDLEVEL LOW IS A BIT FURTHER WEST THAN MOST GLOBAL MODELS ARE
PREDICTING. THUS...THERE MAY BE A CHANCE OF SHRA AT SAT/SSF JUST
AFTER SUNRISE...BUT CONFIDENCE IS TOO LOW TO INCLUDE AT THIS TIME.
THE EVOLUTION OF TSRA OVERNIGHT MAY HAVE SOME EFFECT ON THE
STRENGTH OF ANY SEA BREEZE AND ASSOCIATED CONVECTION THAT DEVELOPS
TOMORROW. ASSUMING THAT ONGOING TSRA DO NOT EXPAND AND DISRUPT THE
DEVELOPMENT OF A SEA BREEZE TOMORROW...EXPECT IT TO PASS THROUGH
SAT/SSF AROUND 20Z AND AUS AROUND 21Z WITH ISOLATED 20-25 KT WIND
GUSTS FOR A FEW HOURS. SHRA AND TSRA COVERAGE SHOULD REMAIN BELOW
20-30 PERCENT...PARTICULARLY AT AUS...SO ONLY INCLUDED VCSH FOR
SAT/SSF AT THIS TIME. WILL REEVALUATE THIS FOR THE 12Z TAF PACKAGE
AFTER SEEING HOW CONVECTION TONIGHT ALONG THE GULF COAST EVOLVES.
&&
.PREV DISCUSSION... /ISSUED 817 PM CDT MON AUG 31 2015/
UPDATE...
CONVECTION HAS DISSIPATED WITH THE LOSS OF DAYTIME HEATING AND
UPDATED THE FORECAST TO TAKE THE MENTION OF RAIN OUT FOR MOST OF
THE CWA...EXCLUDING THE COASTAL PLAINS WHERE SOME ADDITIONAL
ACTIVITY MAY BE POSSIBLE OVERNIGHT EAST OF THE UPPER LOW. UPDATED
PRODUCTS HAVE BEEN SENT.
PREV DISCUSSION... /ISSUED 646 PM CDT MON AUG 31 2015/
AVIATION...
ISOLD SHRA/TSRA CURRENTLY CROSSING I-35 CORRIDOR WILL DISSIPATE BY
01/01Z. EARLIER TSRA AT KSSF AND SHRA AT KAUS HAVE DISSIPATED AND
IMPACTS ARE NO LONGER EXPECTED FOR TONIGHT. ISOLD/SCT SHRA/TSRA
WILL DEVELOP OVER THE COASTAL PLAINS BY MORNING...SPREAD TO THE
WEST ON TUESDAY TO THE I-35 CORRIDOR...AND THEN DISSIPATE WHILE
MOVING INTO THE EASTERN HILL COUNTRY EARLY TUESDAY EVENING. FOR
NOW...MENTIONED VCSH AT KAUS/KSAT/KSSF MID AFTERNOON INTO EARLY
EVENING AND WILL MONITOR RADAR AND MODEL TRENDS FOR UPDATES TO
PRECIP MENTIONS.
VFR SKIES PREVAIL THIS EVENING. STRATUS WITH MVFR CIGS WILL
DEVELOP OVERNIGHT ALONG THE ESCARPMENT AND SPREAD TO NEAR THE RIO
GRANDE BY MORNING. HAVE ONLY SCT020 AT KDRT AS CIGS SHOULD STAY
JUST EAST OF THE SITE. CLOUDS WILL LIFT TO VFR SKIES BY MIDDAY.
EXCEPT LCL MVFR CIGS/VSBYS POSSIBLE IN SHRA/TSRA.
S TO SE WINDS 10 TO 15 KTS THIS EVENING IN THE WAKE OF THE
SEABREEZE...DECREASE TO 7 KTS OR LESS OVERNIGHT. WINDS INCREASE
TO 7 TO 10 KTS TUESDAY MORNING AND THEN BACK WITH PASSAGE OF THE
SEABREEZE WHILE INCREASING TO 10 TO 18 KTS. WIND GUSTS UP TO 35
KTS ARE POSSIBLE IN/NEAR SHRA/TSRA AND WIND GUSTS UP TO 25 KTS ARE
POSSIBLE FOR AN HOUR OR TWO AFTER THE PASSAGE OF THE SEABREEZE.
PREV DISCUSSION... /ISSUED 308 PM CDT MON AUG 31 2015/
SHORT TERM (TONIGHT THROUGH TUESDAY NIGHT)...
NO SIGNIFICANT HIGHLIGHTS THIS PERIOD AS NEAR AVERAGE TEMPERATURES
PERSIST WITH ONLY 20-30% RAIN CHANCES FOR THE COASTAL PLAINS. HEAT
INDEX VALUES WILL MAX OUT IN THE UPPER 90S WITH A FEW SPORADIC 100F
READINGS.
A FEW ISOLATED SHOWERS ARE ONGOING ALONG AN OUTFLOW BOUNDARY MOVING
NORTHWEST ACROSS GONZALES...FAYETTE AND PUSH INTO BASTROP/CALDWELL
AND GUADALUPE OVER THE NEXT HOUR. THESE SHOWERS SHOULD DISSIPATE
OVER THE NEXT FEW HOURS AND NOT LIKELY MAKE IT INTO THE METROPLEXES.
A QUIET OVERNIGHT IS EXPECTED THROUGH 4AM FOR ALL OF THE REGION BUT
A NEW MOISTURE SURGE LOOKS TO MAKE ITS WAY NORTH ALONG THE COAST
WITH SOME SHOWER ACTIVITY INFILTRATING THE COASTAL PLAINS POSSIBLY
BY 6AM. THIS ACTIVITY WILL SPREAD NORTH THROUGH THE MORNING AND
AFTERNOON HOURS PER HI-RES AND GLOBAL MODELS. THIS ACTIVITY SHOULD
SLOWLY DISSIPATE THROUGH THE EVENING HOURS AS THE FAR EAST LOCATIONS
MAY HAVE SHOWERS LINGER THROUGH THE EARLY MORNING HOURS WEDNESDAY.
HOWEVER...THE PROBABILITY OF SHOWERS OVERNIGHT INTO WEDNESDAY WILL
BE 20% AT BEST.
LONG TERM (WEDNESDAY THROUGH MONDAY)...
NO SIGNIFICANT HIGHLIGHTS DURING THE LONG TERM PERIOD AS WELL WITH
RAIN CHANCES DECREASING THROUGH THE END OF THE WEEK AND OVER THE
WEEKEND. IT APPEARS 20-30% RAIN/TSTORM CHANCES WILL BE THE BEST WE
CAN MUSTER THROUGH THIS PERIOD.
BY MID TO LATE WEEK...GLOBAL MODELS DIVERGE IN THE MID AND UPPER
LEVELS WITH THE EVOLUTION OF THE CURRENT CLOSED LOW OVER US. BOTH
MODELS INITIALLY TAKE THE SYSTEM FARTHER EAST OVER THE LOWER
MISSISSIPPI VALLEY WITH THE EC KEEPING IT THERE WHILE THE GFS
RETROGRADES IT BACK TOWARDS US BY FRIDAY. LOOKING AT THE ENSEMBLE
PERTURBATIONS...MORE SUPPORT SEEMS TO BE NOTED FOR THE RETROGRADING
SOLUTION OF AT LEAST A INVERTED TROUGH TO SHIFT BACK TOWARDS THE
TEXAS COAST. FOLLOWING THIS SOLUTION HOWEVER STILL SEEMS TO BE 20-
30% POP WORTH GIVEN THE 700-300MB DIVERGENCE AREA SOUTH TOWARDS
BROWNSVILLE. OVERALL SIGNALS WILL NEED TO BE MONITORED FOR THIS
EVOLUTION AND IF THIS DIVERGENCE AREA SHIFTS NORTH. BY LATE WEEKEND
TO EARLY NEXT WEEK...BETTER RIDGING ACROSS NORTH TEXAS SHOULD
FURTHER THE DRY AND WARM TREND WITH NO LARGE AREAS OF SIGNIFICANT
RAINFALL.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 93 74 94 74 94 / 20 20 20 - 10
AUSTIN BERGSTROM INTL AIRPORT 92 71 93 71 92 / 20 20 20 - 10
NEW BRAUNFELS MUNI AIRPORT 93 73 94 73 94 / 20 20 20 - 10
BURNET MUNI AIRPORT 92 72 92 72 92 / 10 10 10 - 10
DEL RIO INTL AIRPORT 96 75 96 76 96 / 10 10 - - -
GEORGETOWN MUNI AIRPORT 92 73 92 73 92 / 20 20 20 - 10
HONDO MUNI AIRPORT 94 72 94 72 94 / 10 10 10 - 10
SAN MARCOS MUNI AIRPORT 92 72 92 73 92 / 20 20 20 - 10
LA GRANGE - FAYETTE REGIONAL 92 73 93 73 92 / 40 40 30 10 20
SAN ANTONIO INTL AIRPORT 93 75 94 75 93 / 20 20 20 - 10
STINSON MUNI AIRPORT 94 74 94 74 95 / 20 20 20 - 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...LH
SYNOPTIC/GRIDS...24
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1156 PM CDT MON AUG 31 2015
.DISCUSSION...
06Z TAF DISCUSSION IN AVIATION SECTION
&&
.AVIATION...
OVERALL TRENDS IN TAFS REMAIN THE SAME WITH CONVECTION DEVELOPING
IN THE MORNING AND SPREADING INLAND. EXPECT SOME SCT TSRA IN THE
AREA TOMORROW SO WILL KEEP VCTS FOR NOW UNTIL SHORT RANGE MODELS
GET A BETTER HANDLE ON EVOLUTION. DO THINK CONVECTION SHOULD END
IN THE EARLY EVENING HOURS AS BOUNDARY LAYER BECOMES STABLIZED BY
CONVECTION. DO NOT SEE WIDESPREAD CIGS EXCEPT FOR MAYBE SOME BREIF
MVFR CIGS WITH TSRA AND LIMITED VSBY WITH HEAVY RAINFALL.
39
&&
.PREV DISCUSSION... /ISSUED /
DISCUSSION...
THE BROAD UPPER LOW WAS LOCATED WEST OF THE FORECAST AREA AT MID
EVENING. THE NAM12 AND HIGH RESOLUTION MODELS HAVE A LULL IN THE
RAIN ACTIVITY THROUGH THE REMAINDER OF THIS EVENING...BUT THEN
REDEVELOP SHOWERS AND THUNDERSTORMS OVERNIGHT TONIGHT AS A
SHORTWAVE TROUGH MOVES UP THE COAST ON THE EAST SIDE OF THE UPPER
LOW. THE CURRENT RAIN CHANCES WERE ON TRACK. DID TWEAK THE
TEMPERATURES A BIT FOR TONIGHT AND TUESDAY MORNING.
40
PREV DISCUSSION... /ISSUED /
DISCUSSION...
00Z TAF DISCUSSION IN AVIATION SECTION.
AVIATION...
TSRA ACTIVITY HAS COME TO AN END THIS EVENING WITH STILL QUITE A
BIT OF ACTIVITY IN THE NW GULF. THIS SHOULD NOT BE AN IMPACT TO
ANY OF THE TERMINALS. EXPECT VFR CIGS TONIGHT WITH MAYBE SOME
PATCHY FOG AT KCXO.
HI RES SHORT TERM MODELS SHOW SHRA/TSRA DEVELOPING 10-14Z OFF THE
COAST AND PUSHING INLAND. THINK THE HRRR MAY BE A BIT FAST LIKE IT
WAS YESTERDAY FOR TODAY`S CONVECTION. WILL KEEP ONSET ALONG THE
COAST AROUND 10-11Z FOR KGLS/KLBX BUT START ACTIVITY CLOSER TO 14Z
FOR KHOU/KSGR. THINK CONVECTION WILL DEVELOP MORE AS UPPER LOW
MOVES OVER THE REGION LATE MORNING. WILL CARRY VCTS FOR TAFS
MAINLY LATE MORNING THROUGH THE AFTERNOON FOR MAINLY SCATTERED
ACTIVITY. CONVECTION SHOULD COME TO AN END IN THE 22-00Z TIME
FRAME FOR THE END OF THE TAF PERIOD.
39
PREV DISCUSSION... /ISSUED /
DISCUSSION...
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS DEVELOPED ACROSS SOUTHEAST
TEXAS TODAY IN ASSOCIATION WITH THE NEARLY STATIONARY MID/UPPER LEVEL
LOW CENTERED OFF TO OUR WEST AND SOUTHWEST WITH THE BEST COVERAGE IN
AND AROUND THE MATAGORDA BAY AREA. THESE STORMS PRODUCED SOME LOCALLY
HEAVY RAINFALL (RADAR ESTIMATED GENERALLY 1 TO 2 INCH TOTALS WITH SOME
HIGHER AMOUNTS APPROACHING 3 INCHES) FROM IN AND AROUND MATAGORDA BAY
TO THE FREEPORT AREA TO NEAR BRENHAM. MODELS SHOW MORE STORMS DEVELOPING
TONIGHT AND ON INTO TUESDAY MORNING IN ASSOCIATION WITH THE LOW...AND
HAVE MENTIONED LOCALLY HEAVY RAINFALL POSSIBLE FOR LOCATIONS NEAR THE
COAST AND OFFSHORE BEFORE SUNRISE THEN FURTHER INLAND DURING THE MORNING
AND AFTERNOON HOURS. IT IS POSSIBLE THAT THE STRONGEST STORMS AND GREATEST
COVERAGE COULD REMAIN NEAR THE COAST AND OFFSHORE. WITH THE STRONGER
STORMS...EXPECT TO SEE RAINFALL TOTALS OF 2 TO 4 INCHES OR HIGHER. GENERALLY
HIGH END CHANCE POPS NEED TO BE CARRIED IN THE FORECAST ON INTO WEDNESDAY
AS THE LOW SLOWLY EDGES EASTWARD. IF THE LOW MOVES FURTHER OFF TO THE
EAST DURING THE SECOND HALF OF THE WEEK AS SOME MODELS CONTINUE TO
SUGGEST...MUCH OF OUR AREA (ESPECIALLY WELL INLAND UP NORTH) WILL DRY
OUT AND WARM UP. IF THE LOW CONTINUES TO LINGER NEAR US AS OTHER MODELS
CONTINUE TO SUGGEST...WE`LL END UP REMAINING ON THE RAINY SIDE WITH
SLIGHTLY COOLER TEMPERATURES. THIS FORECAST WILL CARRY GRADUALLY LOWERING
RAIN CHANCES AND WARMING TEMPERATURES AS WE HEAD TOWARD THE HOLIDAY
WEEKEND. 42
MARINE...
SCATTERED TO NUMEROUS THUNDERSTORMS CONTINUE ACROSS THE COASTAL
WATERS THIS AFTERNOON. STRONGEST OBSERVED WIND GUSTS FROM BUOYS AND
PLATFORMS THIS AFTERNOON HAVE BEEN IN THE 25 TO 30 KNOT RANGE... BUT
CANNOT RULE OUT SOME STRONGER GUSTS HEADING INTO THE EARLY EVENING
HOURS. A BRIEF LULL IN THIS ACTIVITY IS EXPECTED FOR THE REMAINDER
OF THE EVENING AND INTO THE OVERNIGHT HOURS BEFORE A DISTURBANCE
OVER SOUTH TEXAS TRACKS OVER SOUTHEAST TEXAS LATE TONIGHT AND
TUESDAY. AS THIS HAPPENS... HIGH RESOLUTION GUIDANCE SHOWS ANOTHER
ROUND OF SHOWERS AND THUNDERSTORMS SPREADING NORTHEASTWARD FROM THE
MIDDLE TEXAS COAST TOWARDS THE UPPER TEXAS COAST TUESDAY MORNING.
HEAVY RAINFALL MAY LIMIT VISIBILITIES OVER THE MARINE AREAS TO LESS
THAN 1 NAUTICAL MILE AT TIMES. ADDITIONALLY... TROPICAL FUNNEL
CLOUDS MAY BE OBSERVED ALONG THE COAST WITH A WATERSPOUT OR TWO ALSO
POSSIBLE WITH THIS ACTIVITY THROUGH THE REMAINDER OF TODAY AND AGAIN
TUESDAY GIVEN THE INCREDIBLY BUOYANT AIRMASS IN PLACE. LOCALLY
HIGHER WINDS AND WAVES MAY ALSO BE PRESENT IN STRONGER THUNDERSTORMS.
OTHERWISE... LIGHT ONSHORE WINDS AND SEAS LESS THAN 3 FEET ARE
EXPECTED TO PREVAIL OUTSIDE OF THUNDERSTORM ACTIVITY. ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS WILL REMAIN POSSIBLE FROM
WEDNESDAY THROUGH THE REMAINDER OF THE WEEK AS THE UPPER
DISTURBANCE MEANDERS AROUND THE NORTHWEST GULF OF MEXICO.
HUFFMAN
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 72 91 72 93 72 / 20 30 20 20 20
HOUSTON (IAH) 74 88 72 90 72 / 40 60 50 50 30
GALVESTON (GLS) 79 87 78 87 78 / 60 60 50 50 40
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...40
AVIATION/MARINE...39
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1120 PM CDT MON AUG 31 2015
.AVIATION...
/06Z TAFS/
Expect VFR conditions across West Central Texas during the next
24 hours. The winds will be generally south to southeast with
gusts to around 15 knots Tuesday afternoon.
&&
.PREV DISCUSSION... /ISSUED 700 PM CDT MON AUG 31 2015/
UPDATE...
Isolated thunderstorms failed to materialize this afternoon and
with temperatures already on the decline, the likelihood of later
convection continues to decrease. A well-defined surface boundary
along the I-35 corridor is moving to the west, but will not move
into the area until after the boundary layer has stabilized. Thus,
PoPs were removed from the forecast for this evening. Expect dry
weather and seasonal temperatures overnight, with Tuesday morning
lows in the mid 60s to near 70 degrees.
PREV DISCUSSION... /ISSUED 608 PM CDT MON AUG 31 2015/
AVIATION...
/00Z TAFS/
Expect VFR conditions across West Central Texas during the next
24 hours. The winds will be generally south to southeast with
gusts to around 15 knots Tuesday afternoon.
PREV DISCUSSION... /ISSUED 338 PM CDT MON AUG 31 2015/
SHORT TERM...
(Tonight and Tuesday)
The afternoon cumulus field development is well underway. The TTU
WRF and HRRR models continue to suggest isolated convection will
develop across the southeast third of the forecast area, or
roughly south and east of a Sonora to Eden to Brownwood line
during the next few hours, with any convection dissipating after
sunset. Temperatures dropped to near 60 degrees last night in low-
lying areas under clear skies and light winds. Given the dry soil
conditions in place with similar conditions expected tonight, we
went a couple degrees under guidance to account for this. Sunny
skies and afternoon cumulus are expected for Tuesday, with high
temperatures similar to today, generally in the lower to mid 90s.
LONG TERM...
(Wednesday through Tuesday)
Weak upper level ridge in place across the area will gradually
strengthen across West Central Texas through the period. Low level
thickness and temperature fields are not forecasted by the
models to climb nearly as high as when the last upper level ridge
was in place, but still should be strong enough to keep
temperatures at or a few degrees above normal for the entire
extended. Ridge really nor forecasted to budge much through the
entire first 10 days of September, so it looks like a quiet
extended forecast will continue.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 69 94 71 94 / 0 5 5 0
San Angelo 69 95 70 95 / 0 5 5 5
Junction 67 93 69 91 / 10 5 5 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
21
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1248 PM CDT TUE SEP 1 2015
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 316 AM CDT TUE SEP 1 2015
WATER VAPOR SATELLITE IMAGERY AND RAP ANALYSIS EARLY THIS MORNING
SHOWING A LARGE/DEEP CLOSED LOW ALONG THE COAST OF BRITISH COLUMBIA
WITH DOWNSTREAM RIDGE IN PLACE ACROSS THE EASTERN CONUS/UPPER
MISSISSIPPI RIVER VALLEY REGION. FAIRLY MUGGY AIRMASS IN PLACE
ACROSS THE AREA WITH TEMPERATURES AS OF 3 AM IN THE MIDDLE 60S TO
LOWER 70S WITH DEW POINTS IN THE MIDDLE/UPPER 60S. ALSO SOME AREAS
OF FOG IN HUMID SOUTHERLY FLOW ACROSS PORTIONS OF NORTHEAST
IA/SOUTHEAST MN.
FOR TODAY...LOOK FOR ANY FOG/STRATUS TO BURN OFF BY MID-MORNING.
MEANWHILE...EMBEDDED WEAK MID-LEVEL TROUGH IN GENERAL SOUTHWEST FLOW
ALOFT HEADING NORTHEAST ACROSS NORTHERN WI INTO CANADA EARLY THIS
MORNING AND SHOULD KEEP ANY SHOWER CHANCES NORTH OF OUR FORECAST
AREA. INTERIM RIDGE BUILDS IN THE REST OF TODAY WITH FAIRLY STRONG
800-750MB SUBSIDENCE INVERSION/CAP IN PLACE. WILL SEE SOME CUMULUS
DEVELOPMENT BELOW THE INVERSION...BUT SHOULD REMAIN DRY.
OTHERWISE...MAIN STORY WILL BE HEAT AS HIGHS TOP OFF WELL INTO THE
80S WITH A FEW SPOTS NEARING 90 ACROSS FAR SOUTHWEST WI. COMBINE
THESE TEMPERATURES WITH DEW POINTS IN THE UPPER 60S/LOWER 70S AND
HEAT INDICES IN THE 90S ALONG AND SOUTH OF I-94 WILL BE SEEN.
FOR TONIGHT...MODELS DEPICTING A MID-LEVEL TROUGH EJECTING OUT OF
THE CENTRAL PLAINS TOWARD THE UPPER MISSISSIPPI RIVER REGION. NAM
SHOWING A DECENT SURGE OF 950-700MB MOISTURE TRANSPORT AHEAD OF THE
WAVE. AS A RESULT...WILL BRING A SLIGHT CHANCE OF
SHOWERS/THUNDERSTORMS INTO THE AREA AFTER MIDNIGHT. OTHERWISE...
ANOTHER MUGGY NIGHT IN STORE WITH LOWS ONLY DROPPING INTO THE MIDDLE
60S TO THE LOWER 70S.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 316 AM CDT TUE SEP 1 2015
MODELS SHOW THAT MID-LEVEL TROUGH MENTIONED ABOVE MOVING ACROSS THE
AREA WEDNESDAY/WEDNESDAY NIGHT. COOLER AIR ALOFT/STEEPER MID-LEVEL
LAPSE RATES WILL SERVE AS TRIGGER FOR SCATTERED
SHOWERS/THUNDERSTORMS. NAM DEPICTING 0-3KM MUCAPE IN THE 4-5KJ/KG BY
AFTERNOON BUT MAY BE A BIT OVERDONE GIVEN ITS HIGHER DEWPOINT BIAS.
BULK SHEAR ONLY 15-20KT. SO...LOOKING FOR MAINLY PULSE TYPE
THUNDERSTORMS. CANNOT RULE OUT SOME SUB-SEVERE HAIL AND WIND WITH
THE STRONGER STORMS DURING THE LATE AFTERNOON. MEANWHILE...VERY
WARM/MUGGY CONDITIONS CONTINUE WITH HIGHS WELL INTO THE 80S/FEW
LOWER 90S WITH HEAT INDICES IN THE UPPER 80S TO MIDDLE 90S.
STILL A CHANCE OF A FEW LINGERING SHOWER/STORMS THURSDAY MAINLY EAST
OF THE MISSISSIPPI RIVER AS THE WAVE DEPARTS OFF TO THE EAST. LOOK
FOR HIGHS WELL INTO THE 80S AGAIN WITH HEAT INDICES AGAIN IN THE
UPPER 80S TO THE MIDDLE 90S.
THURSDAY NIGHT THROUGH SATURDAY NIGHT LOOKS LIKE A DRY PERIOD AS
LATEST GFS/NAM SHOWING MID/UPPER RIDGE AMPLIFICATION ACROSS THE
REGION. IT WILL REMAIN VERY WARM AND MUGGY THROUGH THIS PERIOD WITH
HIGHS FRIDAY AND SATURDAY STAYING WELL INTO THE 80S/NEAR 90.
OVERNIGHT LOWS LOOK TO REMAIN IN THE MIDDLE 60/NEAR 70 RANGE.
SHOWER/THUNDERSTORM CHANCES INCREASE SUNDAY AFTERNOON INTO LABOR DAY
AS BOTH THE ECMWF/GFS BREAK DOWN THE RIDGE WITH APPROACHING NORTHERN
PLAINS TROUGH/COLD FRONT. CONFIDENCE INCREASING ENOUGH TO GO WITH
LIKELY POPS SUNDAY NIGHT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1248 PM CDT TUE SEP 1 2015
A SHORTWAVE TROUGH WILL APPROACH THE REGION FROM NEBRASKA/SOUTH
DAKOTA TONIGHT BRINGING INCREASING HIGH AND MID LEVEL CLOUDS TO
THE TAF SITES ALONG WITH THE POSSIBILITY OF SOME SHOWERS AND
THUNDERSTORMS LATE TONIGHT INTO WEDNESDAY MORNING. AHEAD OF THE
TROUGH WINDS WILL INCREASE INTO THE 25 TO 30 KT RANGE FROM 500
THROUGH AROUND 2 FT. THINKING SURFACE WINDS WILL STAY UP JUST
ENOUGH TO PREVENT LLWS BUT WILL HAVE TO KEEP A CLOSE EYE ON
SURFACE WINDS TONIGHT. WITH THESE WINDS INCREASING WE SHOULD SEE
ENOUGH MIXING TO PREVENT FOG BUT CANNOT RULE OUT SOME MVFR
VISIBILITIES IN HAZE WITH SOME SMOKE ACROSS THE REGION COMBINED
WITH A MOIST AIRMASS. HAVE KEPT THUNDERSTORMS OUT OF THE TAFS AT
THIS TIME WITH LOW CONFIDENCE THAT THEY WILL IMPACT THE TAF SITES.
MAY HAVE TO INCLUDE THEM IN THE KRST TAF IF MESOSCALE MODEL TRENDS
CONTINUE THIS AFTERNOON.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
635 AM CDT TUE SEP 1 2015
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 316 AM CDT TUE SEP 1 2015
WATER VAPOR SATELLITE IMAGERY AND RAP ANALYSIS EARLY THIS MORNING
SHOWING A LARGE/DEEP CLOSED LOW ALONG THE COAST OF BRITISH COLUMBIA
WITH DOWNSTREAM RIDGE IN PLACE ACROSS THE EASTERN CONUS/UPPER
MISSISSIPPI RIVER VALLEY REGION. FAIRLY MUGGY AIRMASS IN PLACE
ACROSS THE AREA WITH TEMPERATURES AS OF 3 AM IN THE MIDDLE 60S TO
LOWER 70S WITH DEW POINTS IN THE MIDDLE/UPPER 60S. ALSO SOME AREAS
OF FOG IN HUMID SOUTHERLY FLOW ACROSS PORTIONS OF NORTHEAST
IA/SOUTHEAST MN.
FOR TODAY...LOOK FOR ANY FOG/STRATUS TO BURN OFF BY MID-MORNING.
MEANWHILE...EMBEDDED WEAK MID-LEVEL TROUGH IN GENERAL SOUTHWEST FLOW
ALOFT HEADING NORTHEAST ACROSS NORTHERN WI INTO CANADA EARLY THIS
MORNING AND SHOULD KEEP ANY SHOWER CHANCES NORTH OF OUR FORECAST
AREA. INTERIM RIDGE BUILDS IN THE REST OF TODAY WITH FAIRLY STRONG
800-750MB SUBSIDENCE INVERSION/CAP IN PLACE. WILL SEE SOME CUMULUS
DEVELOPMENT BELOW THE INVERSION...BUT SHOULD REMAIN DRY.
OTHERWISE...MAIN STORY WILL BE HEAT AS HIGHS TOP OFF WELL INTO THE
80S WITH A FEW SPOTS NEARING 90 ACROSS FAR SOUTHWEST WI. COMBINE
THESE TEMPERATURES WITH DEW POINTS IN THE UPPER 60S/LOWER 70S AND
HEAT INDICES IN THE 90S ALONG AND SOUTH OF I-94 WILL BE SEEN.
FOR TONIGHT...MODELS DEPICTING A MID-LEVEL TROUGH EJECTING OUT OF
THE CENTRAL PLAINS TOWARD THE UPPER MISSISSIPPI RIVER REGION. NAM
SHOWING A DECENT SURGE OF 950-700MB MOISTURE TRANSPORT AHEAD OF THE
WAVE. AS A RESULT...WILL BRING A SLIGHT CHANCE OF
SHOWERS/THUNDERSTORMS INTO THE AREA AFTER MIDNIGHT. OTHERWISE...
ANOTHER MUGGY NIGHT IN STORE WITH LOWS ONLY DROPPING INTO THE MIDDLE
60S TO THE LOWER 70S.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 316 AM CDT TUE SEP 1 2015
MODELS SHOW THAT MID-LEVEL TROUGH MENTIONED ABOVE MOVING ACROSS THE
AREA WEDNESDAY/WEDNESDAY NIGHT. COOLER AIR ALOFT/STEEPER MID-LEVEL
LAPSE RATES WILL SERVE AS TRIGGER FOR SCATTERED
SHOWERS/THUNDERSTORMS. NAM DEPICTING 0-3KM MUCAPE IN THE 4-5KJ/KG BY
AFTERNOON BUT MAY BE A BIT OVERDONE GIVEN ITS HIGHER DEWPOINT BIAS.
BULK SHEAR ONLY 15-20KT. SO...LOOKING FOR MAINLY PULSE TYPE
THUNDERSTORMS. CANNOT RULE OUT SOME SUB-SEVERE HAIL AND WIND WITH
THE STRONGER STORMS DURING THE LATE AFTERNOON. MEANWHILE...VERY
WARM/MUGGY CONDITIONS CONTINUE WITH HIGHS WELL INTO THE 80S/FEW
LOWER 90S WITH HEAT INDICES IN THE UPPER 80S TO MIDDLE 90S.
STILL A CHANCE OF A FEW LINGERING SHOWER/STORMS THURSDAY MAINLY EAST
OF THE MISSISSIPPI RIVER AS THE WAVE DEPARTS OFF TO THE EAST. LOOK
FOR HIGHS WELL INTO THE 80S AGAIN WITH HEAT INDICES AGAIN IN THE
UPPER 80S TO THE MIDDLE 90S.
THURSDAY NIGHT THROUGH SATURDAY NIGHT LOOKS LIKE A DRY PERIOD AS
LATEST GFS/NAM SHOWING MID/UPPER RIDGE AMPLIFICATION ACROSS THE
REGION. IT WILL REMAIN VERY WARM AND MUGGY THROUGH THIS PERIOD WITH
HIGHS FRIDAY AND SATURDAY STAYING WELL INTO THE 80S/NEAR 90.
OVERNIGHT LOWS LOOK TO REMAIN IN THE MIDDLE 60/NEAR 70 RANGE.
SHOWER/THUNDERSTORM CHANCES INCREASE SUNDAY AFTERNOON INTO LABOR DAY
AS BOTH THE ECMWF/GFS BREAK DOWN THE RIDGE WITH APPROACHING NORTHERN
PLAINS TROUGH/COLD FRONT. CONFIDENCE INCREASING ENOUGH TO GO WITH
LIKELY POPS SUNDAY NIGHT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 635 AM CDT TUE SEP 1 2015
LIFR/IFR FOG AT KRST WILL LIFT AND DISSIPATE BY 01.14Z...ALTHOUGH
MVFR VISIBILITY IN MIST LIKELY TO CONTINUE FOR MUCH OF THE MORNING.
DO EXPECT A RETURN TO VFR CONDITIONS BY 01.16Z. MVFR MIST AT KLSE
ALSO EXPECTED TO DISSIPATE BY 01.14Z WITH A QUICKER RETURN TO VFR
CONDITIONS. FOR BOTH SITES...EXPECT SOME AFTERNOON CUMULUS WITH
SOME ADDITIONAL HIGHER LEVEL CLOUDS. LIGHT SOUTHERLY WINDS WILL BE
THE RULE THROUGH THE PERIOD.
FOR TONIGHT...THINK THERE WILL BE ENOUGH MID-HIGH LEVEL CLOUD
COVER COMBINED WITH 15 TO 20 KTS ABOVE THE NOCTURNAL INVERSION TO
LIMIT FOG FORMATION AT BOTH KLSE/KRST. HOWEVER...PERSISTENT HIGH
SURFACE DEW POINTS LIKELY TO RESULT IN AT LEAST A RETURN TO MVFR
MIST AFTER 02.05Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...ROGERS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
316 AM CDT TUE SEP 1 2015
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 316 AM CDT TUE SEP 1 2015
WATER VAPOR SATELLITE IMAGERY AND RAP ANALYSIS EARLY THIS MORNING
SHOWING A LARGE/DEEP CLOSED LOW ALONG THE COAST OF BRITISH COLUMBIA
WITH DOWNSTREAM RIDGE IN PLACE ACROSS THE EASTERN CONUS/UPPER
MISSISSIPPI RIVER VALLEY REGION. FAIRLY MUGGY AIRMASS IN PLACE
ACROSS THE AREA WITH TEMPERATURES AS OF 3 AM IN THE MIDDLE 60S TO
LOWER 70S WITH DEW POINTS IN THE MIDDLE/UPPER 60S. ALSO SOME AREAS
OF FOG IN HUMID SOUTHERLY FLOW ACROSS PORTIONS OF NORTHEAST
IA/SOUTHEAST MN.
FOR TODAY...LOOK FOR ANY FOG/STRATUS TO BURN OFF BY MID-MORNING.
MEANWHILE...EMBEDDED WEAK MID-LEVEL TROUGH IN GENERAL SOUTHWEST FLOW
ALOFT HEADING NORTHEAST ACROSS NORTHERN WI INTO CANADA EARLY THIS
MORNING AND SHOULD KEEP ANY SHOWER CHANCES NORTH OF OUR FORECAST
AREA. INTERIM RIDGE BUILDS IN THE REST OF TODAY WITH FAIRLY STRONG
800-750MB SUBSIDENCE INVERSION/CAP IN PLACE. WILL SEE SOME CUMULUS
DEVELOPMENT BELOW THE INVERSION...BUT SHOULD REMAIN DRY.
OTHERWISE...MAIN STORY WILL BE HEAT AS HIGHS TOP OFF WELL INTO THE
80S WITH A FEW SPOTS NEARING 90 ACROSS FAR SOUTHWEST WI. COMBINE
THESE TEMPERATURES WITH DEW POINTS IN THE UPPER 60S/LOWER 70S AND
HEAT INDICES IN THE 90S ALONG AND SOUTH OF I-94 WILL BE SEEN.
FOR TONIGHT...MODELS DEPICTING A MID-LEVEL TROUGH EJECTING OUT OF
THE CENTRAL PLAINS TOWARD THE UPPER MISSISSIPPI RIVER REGION. NAM
SHOWING A DECENT SURGE OF 950-700MB MOISTURE TRANSPORT AHEAD OF THE
WAVE. AS A RESULT...WILL BRING A SLIGHT CHANCE OF
SHOWERS/THUNDERSTORMS INTO THE AREA AFTER MIDNIGHT. OTHERWISE...
ANOTHER MUGGY NIGHT IN STORE WITH LOWS ONLY DROPPING INTO THE MIDDLE
60S TO THE LOWER 70S.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 316 AM CDT TUE SEP 1 2015
MODELS SHOW THAT MID-LEVEL TROUGH MENTIONED ABOVE MOVING ACROSS THE
AREA WEDNESDAY/WEDNESDAY NIGHT. COOLER AIR ALOFT/STEEPER MID-LEVEL
LAPSE RATES WILL SERVE AS TRIGGER FOR SCATTERED
SHOWERS/THUNDERSTORMS. NAM DEPICTING 0-3KM MUCAPE IN THE 4-5KJ/KG BY
AFTERNOON BUT MAY BE A BIT OVERDONE GIVEN ITS HIGHER DEWPOINT BIAS.
BULK SHEAR ONLY 15-20KT. SO...LOOKING FOR MAINLY PULSE TYPE
THUNDERSTORMS. CANNOT RULE OUT SOME SUB-SEVERE HAIL AND WIND WITH
THE STRONGER STORMS DURING THE LATE AFTERNOON. MEANWHILE...VERY
WARM/MUGGY CONDITIONS CONTINUE WITH HIGHS WELL INTO THE 80S/FEW
LOWER 90S WITH HEAT INDICES IN THE UPPER 80S TO MIDDLE 90S.
STILL A CHANCE OF A FEW LINGERING SHOWER/STORMS THURSDAY MAINLY EAST
OF THE MISSISSIPPI RIVER AS THE WAVE DEPARTS OFF TO THE EAST. LOOK
FOR HIGHS WELL INTO THE 80S AGAIN WITH HEAT INDICES AGAIN IN THE
UPPER 80S TO THE MIDDLE 90S.
THURSDAY NIGHT THROUGH SATURDAY NIGHT LOOKS LIKE A DRY PERIOD AS
LATEST GFS/NAM SHOWING MID/UPPER RIDGE AMPLIFICATION ACROSS THE
REGION. IT WILL REMAIN VERY WARM AND MUGGY THROUGH THIS PERIOD WITH
HIGHS FRIDAY AND SATURDAY STAYING WELL INTO THE 80S/NEAR 90.
OVERNIGHT LOWS LOOK TO REMAIN IN THE MIDDLE 60/NEAR 70 RANGE.
SHOWER/THUNDERSTORM CHANCES INCREASE SUNDAY AFTERNOON INTO LABOR DAY
AS BOTH THE ECMWF/GFS BREAK DOWN THE RIDGE WITH APPROACHING NORTHERN
PLAINS TROUGH/COLD FRONT. CONFIDENCE INCREASING ENOUGH TO GO WITH
LIKELY POPS SUNDAY NIGHT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1148 PM CDT MON AUG 31 2015
CONFIDENCE IS LOW ON HOW THE NEXT SEVERAL HOURS WILL EVOLVE.
OBSERVATIONS SHOW A FAIRLY WIDESPREAD MVFR FOG HAS SETUP OVER THE
REGION IN SOUTHERLY FLOW...WITH ISOLATED IFR FOG. THERE IS SOME
MOISTURE EXTENDING FROM ABOUT KEAU TO KALO AND WEST THAT IS
FORMING A SCT050 DECK AROUND THE AREA AS WELL.
OVER THE NEXT HOURS THE MODEL GUIDANCE WOULD SUGGEST THAT
CLOUDS/FOG WILL FORM GENERALLY IN THE MOIST AXIS. THUS HAVE
BROUGHT CONDITIONS INTO IFR AT KRST MORE IN THE MOIST PLUME...AND
MVFR AT KLSE.
WITH SOME DRYING WORKING IN FROM THE SOUTHWEST...CONDITIONS SHOULD
IMPROVE RAPIDLY DURING THE EARLY MORNING HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION
NWS TUCSON AZ
950 PM MST WED SEP 2 2015
.SYNOPSIS...THERE IS A GOOD CHANCE OF SHOWERS AND THUNDERSTORMS
THURSDAY AFTERNOON AND EVENING. ISOLATED TO SCATTERED THUNDERSTORMS
WILL THEN PREVAIL FRIDAY INTO EARLY NEXT WEEK. THE BULK OF THIS
ACTIVITY WILL OCCUR FROM TUCSON EAST AND SOUTH WITH LESSER CHANCES
WEST OF TUCSON. EXPECT REDUCED THUNDERSTORM CHANCES BY THE MIDDLE OF
NEXT WEEK.
&&
.DISCUSSION...IR SATELLITE IMAGERY AND SURFACE OBSERVATIONS DEPICTED
PARTLY CLOUDY TO CLOUDY SKIES FROM TUCSON EWD TO THE NEW MEXICO
BORDER AT THIS TIME. MEANWHILE...CLEAR SKIES PREVAILED ACROSS WRN
PIMA COUNTY. THIS FORECAST AREA WAS VOID OF PRECIP ECHOES VALID
0445Z AS PER KEMX WSR-88D. HOWEVER...A THUNDERSTORM COMPLEX
WAS MOVING NEWD ACROSS NERN SONORA MEXICO...AND CLOUD TOPS WERE
COOLING ACROSS FAR SERN SECTIONS AHEAD OF THIS RELATIVELY SMALL MCS.
BASED ON SATELLITE/RADAR TRENS AS WELL AS THE 03/00Z NAM12 AND
SEVERAL HRRR SOLUTIONS...HAVE MAINTAINED A SLIGHT CHANCE OF SHOWERS/
TSTMS ACROSS MUCH OF SE ARIZONA THE REST OF TONIGHT. PRECIP-FREE
CONDITIONS WILL CONTINUE ACROSS WRN PIMA COUNTY.
HOWEVER...HAVE NOTED SOME DIFFERENCES BETWEEN THE HRRR SOLUTIONS AND
THE NAM12 REGARDING PRECIP POTENTIAL INTO EARLY THUR MORNING. THE
HRRR HAS BEEN CONSISTENT WITH DEVELOPING MOSTLY LIGHT RAIN AMOUNTS
ACROSS COCHISE COUNTY LATER TONIGHT...ESSENTIALLY AROUND 10Z...THEN
EXPANDING THE COVERAGE OF SHOWERS/TSTMS NWWD INTO ERN PIMA/SE PINAL
COUNTIES AROUND DAYBREAK THUR.
MEANWHILE...THE NAM12 DEPICTED MEASURABLE RAINFALL TO OCCUR LATER
TONIGHT MAINLY CONFINED TO PORTIONS OF GRAHAM COUNTY AND NERN PIMA
COUNTY. THEREAFTER...THE NAM12 DEPICTED FAIRLY EXTENSIVE COVERAGE OF
LIGHT TO MODERATE RAIN AMOUNTS TO OCCUR ACROSS MUCH OF THE AREA BY
LATE THUR MORNING...THEN HEAVIER AMOUNTS TO OCCUR ESPECIALLY SE OF
TUCSON THUR AFTERNOON.
AT ANY RATE...THE OFFICIAL FORECAST CONTINUES WITH AT LEAST A SLIGHT
CHANCE OF SHOWERS/TSTMS ACROSS MUCH OF THE AREA THUR MORNING...THEN
AT LEAST CHANCE-CATEGORY POPS ACROSS MUCH OF THIS FORECAST AREA THUR
AFTERNOON/EVENING. HIGH TEMPS THUR ARE FORECAST TO AVERAGE ABOUT
5 DEGS F COOLER VERSUS TEMPS ACHIEVED THIS AFTERNOON.
PLEASE REFER TO THE ADDITIONAL SECTIONS FOR FURTHER DETAIL.
&&
.AVIATION...VALID THRU 04/06Z.
ISOLATED -TSRA/-SHRA WILL OCCUR INTO THURSDAY MORNING...WITH THE
BULK OF THIS ACTIVITY SE OF KTUS AND ESPECIALLY IN THE VICINITY OF
THE KDUG TERMINAL. SCATTERED TO NUMEROUS -TSRA/-SHRA WILL THEN OCCUR
ACROSS MUCH OF THE AREA THURSDAY AFTERNOON AND EVENING. MVFR
CONDITIONS AND WIND GUSTS OF 35-45 KTS WILL OCCUR WITH THE STRONGER
TSRA. OTHERWISE...EXPECT LAYERED CLOUDS MOSTLY BETWEEN 8-15K FT AGL
AND SURFACE WIND GENERALLY LESS THAN 10 KTS INTO THURSDAY EVENING.
AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...A GOOD CHANCE OF THUNDERSTORMS WILL PREVAIL
THURSDAY AND THURSDAY EVENING...PARTICULARLY FROM TUCSON EAST AND
SOUTH TO THE NEW MEXICO/INTERNATIONAL BORDERS. ISOLATED TO
SCATTERED THUNDERSTORMS WILL THEN OCCUR FRIDAY INTO EARLY NEXT
WEEK. THE LEAST ACTIVITY WILL OCCUR ACROSS FIRE ZONE 150 WEST
TO NORTHWEST OF TUCSON. BRIEF STRONG...GUSTY AND ERRATIC WINDS WILL
ACCOMPANY THE STRONGER THUNDERSTORMS. A GRADUAL DRYING TREND WILL
LEAD TO LESS THUNDERSTORM ACTIVITY BY NEXT WEDNESDAY. OTHERWISE...
EXPECT TERRAIN DRIVEN WINDS MOSTLY LESS THAN 15 MPH INTO NEXT WEEK.
&&
.PREV DISCUSSION /135 PM MST/...THURSDAY THERE IS ANOTHER IMPULSE ON
ITS WAY TO AFFECT THE AREA ALTHOUGH MODELS INDICATE THAT IT MAY BE A
FEW HOURS LATER THAN TODAYS PUTTING THE FOCUS LATER IN THE DAY AND
OVERNIGHT THURSDAY. AGAIN THE POTENTIAL FOR LOCAL FLOODING AND WET
MICROBURST ACTIVITY. SHOULD BE ENOUGH FLOW ALOFT TO RESET THE
ATMOSPHERE SO WILL MAINTAIN THE RELATIVELY HIGH POPS.
BEYOND THAT WE STILL MAINTAIN A SOUTH TO SW FLOW ACROSS THE AREA
WITH MOISTURE STREAMING NORTH SATURDAY AND SUNDAY ALTHOUGH THE
MOISTURE ISN/T QUITE AS HIGH. COULD/SHOULD ALSO HAVE SOME
DISTURBANCES IN THAT FLOW TO HELP CONVECTION AT TIMES ALTHOUGH TOO
EARLY TO TRY TO CAPTURE AND TIME THOSE. THROUGH OUT THE THURSDAY
THROUGH SUNDAY TIME FRAME...DUE TO CLOUDS...PRECIPITATION AND LOWER
THICKNESS VALUES HIGH TEMPERATURES WILL BE SEVERAL DEGREES BELOW
NORMAL.
THEN BOTH THE GFS (WHICH PICKED THIS WHOLE SCENARIO UP WELL THUS
FAR) AND THE ECMWF INDICATED A MORE SIGNIFICANT DISTURBANCE WILL
ROTATE UP THROUGH HERE WITH A FAIR AMOUNT OF MOISTURE. THE DETAILS
DIFFER...HOWEVER WITH BOTH SHOWING A SIMILAR IDEA THIS FAR OUT IT
NEEDS TO BE NOTED. IF IT WERE TO COME TO PASS IT SHOULD PROVIDE FOR
ANOTHER VERY ACTIVE DAY OF CONVECTION. THEN BEYOND THAT THE TREND
IS TO A MORE WESTERLY FLOW WHICH WOULD SLOWLY DRY OUT THE AIR MASS
WITH TEMPERATURES CLIMBING BACK UP TO NORMAL LEVELS.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1100 PM MDT WED SEP 2 2015
.UPDATE...
ISSUED AT 707 PM MDT WED SEP 2 2015
UPDATED MAINLY POPS IN THE GRIDS/ZONES TO REFLECT LATEST
RADAR TRENDS AND HI RES GUIDANCE. LOTS OF UPSTREAM CONVECTION
STILL MOVING NORTHWARD THROUGH NRN NM...AND SOME OF THIS SHOULD
MOVE INTO SC AND SE CO THIS EVENING.BEST COVERAGE WILL BE OVER THE
ERN MTS AND SURROUNDING AREAS OVER THE NEXT FEW HOURS. WITHOUT ANY
STRONG FORCING...SHOULD SEE CONVECTION DIMINISH LATER THIS EVE BUT
CANNOT RULE OUT SOME ISOLD ACTIVITY OVER THE LOWER ELEVATIONS.
LATE TONIGHT...WILL START TO SEE THE INFLUENCE OF A SURGE OF
MONSOONAL MOISTURE INTO SW CO...SO HAVE BOOSTED POPS SLIGHTLY
EARLY THU FOR THE CONTDVD. ROSE
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 307 PM MDT WED SEP 2 2015
CONVECTION SLOWLY BEGINNING TO INCREASE ACROSS THE AREA THIS
AFTERNOON...WITH STORMS MOST NUMEROUS OVER THE SOUTHWEST MOUNTAINS
AND ALONG THE NM BORDER WHERE MOISTURE AND INSTABILITY IS GREATEST.
FOR THE REST OF THE AFTERNOON INTO THE EVENING...EXPECT CONVECTION
TO EXPAND SOMEWHAT OVER THE MOUNTAINS AND INTERIOR VALLEYS AS WEAK
UPPER WAVE AND INCREASING MID LEVEL MOISTURE MOVE INTO CO FROM
NORTHWESTERN NM. HRRR SUGGESTS SOME WEAKENING STORMS TO PERHAPS
REACH THE I-25 CORRIDOR AROUND KPUB AND KCOS THIS EVENING...THOUGH
RATHER LOW CAPE (200-400 J/KG) ACROSS THESE AREAS SUGGESTS STORMS
WILL STAY ISOLATED AND WEAK. A FEW STORMS WILL ALSO BE POSSIBLE
ALONG THE NORTH SLOPE OF THE RATON MESA EASTWARD ACROSS LAS ANIMAS
COUNTY...WHILE REMAINDER OF THE PLAINS SHOULD BE TOO STABLE TO
SUPPORT ANY EVENING CONVECTION. OVERNIGHT...STORMS WILL END OVER
THE EASTERN HALF OF THE AREA...WHILE A FEW -SHRA/WEAK -TSRA HANG
ON ALONG THE CONTINENTAL DIVIDE WHERE MOISTURE CONTINUES TO ADVECT
NORTHWARD FROM AZ/NM.
ON THU...EXPECT FAIRLY WIDESPREAD CONVECTION OVER THE MOUNTAINS FROM
THE SANGRES WESTWARD AS DEEP MOIST AIR MASS WILL BE OVER THE
AREA...WHILE EASTERN MOUNTAIN SLOPES/I25 CORRIDOR/SOUTHEAST PLAINS
SEE MUCH LESS ACTIVITY UNDER RATHER UNFAVORABLE W-SW WINDS AT THE
SURFACE AND ALOFT. GIVEN RATHER HEALTHY PRECIPITABLE WATER
VALUES...STORMS OVER THE HIGHER TERRAIN WILL HAVE THE POTENTIAL FOR
FAIRLY HEAVY RAINFALL RATES...THOUGH RELATIVELY STRONG STEERING
CURRENTS SHOULD KEEP ACTIVITY MOVING AND REDUCE THE FLOOD HAZARD
SOMEWHAT. MAX TEMPS OVER THE MOUNTAINS AND VALLEYS SHOULD COOL A FEW
DEGREES FROM WED MAXES...WHILE I-25 CORRIDOR AND EASTERN PLAINS
SEE LITTLE CHANGE WITH RATHER HOT TEMPS PERSISTING.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 307 PM MDT WED SEP 2 2015
THURSDAY NIGHT THROUGH SATURDAY...FAIRLY GOOD MODEL AGREEMENT
BETWEEN THE GFS AND EC INTO THE WEEKEND...AS COLORADO REMAINS IN THE
MIDDLE OF A RIDGE OF HIGH PRESSURE TO THE EAST.,..AND A
STRENGTHENING LOW PRESSURE SYSTEM OVER THE PAC NW. THIS WILL PRODUCE
BRISK SW FLOW ALOFT ACROSS THE 4 CORNERS AND COLORADO...DRAWING A
HEALTHY AMOUNT OF MONSOON MOISTURE INTO THE FORECAST AREA. THIS WILL
ALSO ENCOURAGE DIURNAL CONVECTION EACH AFTERNOON AND
EVENING...WITH ISOLATED TO SCATTERED POPS OVER THE MTS AND
ISOLATED ELSEWHERE. LOOK FOR MILD NIGHTS...AND MAX TEMPS EACH
AFTERNOON IN THE 70S TO NEAR 80 FOR THE HIGH VALLEYS...AND AROUND
90 F FOR THE E PLAINS.
SUNDAY AND MONDAY...MODELS START TO DISAGREE BEGINNING ON SUN. THE
UPPER LOW OVER THE PAC NW WILL ROTATE ACROSS THE NORTHERN ROCKIES ON
SAT...MT ON SUN AND BACK NORTH INTO CANADA FOR MON. THE FLOW ALOFT
WILL TRANSITION TO A MORE WESTERLY DIRECTION...TEMPORARILY CUTTING
OFF THE MONSOON TAP FROM THE SW. MODELS SOMEWHAT AGREE ON THIS...BUT
THE GFS STARTS TO SNEAK MOISTURE BACK UP INTO THE STATE MON
AFTERNOON AND EVE. FEEL THIS IS REASONABLE SINCE THERE WILL STILL
BE PLENTY OF DAYTIME HEATING...SO KEPT ISOLATED POPS OVER THE
MTS...MAINLY ALONG THE CONTDVD...MON AFTERNOON AND EVE.
TUESDAY AND WEDNESDAY...THE EC LEANS TOWARDS KEEPING THE ENTIRE AREA
DRY THROUGH WED...WHILE THE GFS HAS MORE OF A SW FLOW ALOFT WHICH
ATTEMPTS TO DRAW SOME OF THE MONSOON MOISTURE BACK INTO THE STATE.
DECIDED TO SIDE WITH THE GFS...BUT KEPT POPS LIGHT THROUGH WED WHILE
COOLING MAX TEMPS BOTH DAYS BY ABOUT 5 DEGREES. MOORE
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1045 PM MDT WED SEP 2 2015
MONSOON PATTERN WILL CONTINUE NEXT 24 HOURS. SHOULD SEE INCREASE
IN THUNDERSTORM COVERAGE AND STRENGTH OVER THE MOUNTAINS TOMORROW
ALTHOUGH LITTLE CHANGE IS EXPECTED ACROSS THE PLAINS. GENERALLY
VFR ACROSS FLIGHT AREA BUT MVFR/IFR/LIFR FLIGHT CONDITIONS WILL
BE POSSIBLE IN AREAS OF PRECIPITATION...ESPECIALLY OVER THE
MOUNTAINS...AND ESPECIALLY 18Z-00Z. HEAVY RAIN...FLASH
FLOODING...GUSTY WINDS AND LIGHTNING ARE MAIN STORM
THREATS...ESPECIALLY OVER THE MOUNTAINS.
BEST CHANCE OF THUNDERSTORMS TOMORROW WILL BE AT KALS. FOR
NOW...WILL CARRY VCTS AT KALS 17Z-04Z THURSDAY. SECOND BEST CHANCE
OF A TERMINAL STORM IS AT KCOS. WILL CARRY VCTS THERE 18Z-04Z
THURSDAY. FOR KPUB...CURRENTLY LOOKS LIKE THUNDERSTORMS WILL
REMAIN TOO FAR WEST TO INCLUDE IN TERMINAL FORECAST SO NO MENTION
THERE AT THIS TIME. ALL 3 TAFS WILL BE SUBJECT TO AMENDMENTS TOMORROW
AFTERNOON PENDING CONVECTIVE EVOLUTION.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...ROSE
SHORT TERM...PETERSEN
LONG TERM...MOORE
AVIATION...LW
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1138 PM CDT WED SEP 2 2015
...Update to aviation forecast discussion...
.SHORT TERM...(THIS EVENING THROUGH Thursday)
ISSUED AT 307 PM CDT WED SEP 2 2015
19z sfc map shows low pressure across the northern plains with a
trough extending south into western KS with most of eastern Kansas
now mixed out into the warm sector as remnants of elevated
convection wane. Water vapor loop shows a wave across Nebraska
moving E along the northern periphery of the upper ridge axis.
For tonight, the wave will track into northern MO overnight and may
help to enhance the LLJ which will contribute to modest WAA around
850mb. There is some additional WAA fcst to occur around the 700mb
level as well. Interesting that both the RAP and HRRR and GFS are
showing some small areas of QPF across central KS overnight despite
the 850mb thetae ridge remaining north of the CWA overnight. This
appears to be due to modest lift and saturation around 700-650mb
where even the NAM soundings show saturation after 6z. Fcst
soundings suggest modest elevated CAPE of 100j/kg or less. Other
convective models do not show this weak lift resulting in saturation
or convection so for now will keep the pops below 15 and keep the
fcst dry but something to watch for overnight.
We should see another day much like today on Thursday with 1000-
850mb thickness and temps nearly identical to today so will go with
persistence for temps. Pressure gradient is also similar so look for
another breezy day as well.
.LONG TERM...(Thursday NIGHT THROUGH Wednesday)
ISSUED AT 307 PM CDT WED SEP 2 2015
Thursday night through Saturday...Deep, moist southerly low-level
flow will continue through the period. With stronger south-
southwest flow aloft off to our west and northwest, no
recognizable dynamic feature is depicted in the short range
guidance to focus showers and thunderstorms in eastern KS. Only
possibility would be the remnants of some High Plains convective
cluster that might migrate into north central KS/south central/NE
before dissipating. Would expect any system like that to die out
before affecting our northwestern forecast area.
Saturday night through Wednesday...Strong upper trough over the
Rockies on Saturday evening will move northeast into southern
Manitoba and become an occluded system by Monday morning. While
strong dynamics are well to the north, southern extent of system
is a cold front that moves into central/eastern KS and then
becomes nearly stationary. This will be the focus for thunderstorm
chances late in the weekend into early next week. Medium range
models have some differences in the location of this boundary
already by Monday, but all depict it in the area with periodic
chances of thunderstorms into Tuesday night/Wednesday morning.
Then another strong trough moves across the central U.S. with the
result that the front pushes south of the area by late Wednesday.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z Thursday NIGHT)
ISSUED AT 1138 PM CDT WED SEP 2 2015
For the 06z TAFs, VFR conditions are expected through the period.
There is a slight chance for a few isolated showers to develop early
Thursday morning, however confidence is not high enough on the
probability of these showers developing (let alone where they would
develop) to include in the TAFs at this time, but will continue to
monitor this potential. Otherwise, southerly winds will become
more gusty Thursday afternoon.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Omitt
LONG TERM...GDP
AVIATION...Hennecke
AREA FORECAST DISCUSSION
NWS PADUCAH KY
327 AM CDT THU SEP 3 2015
.SHORT TERM...(Today through Saturday)
Issued at 327 AM CDT THU SEP 3 2015
The 00Z models try to pinch the upper ridge from the east Friday
into Saturday, which leads to a little bit more pronounced surface
ridging by Saturday. The models are spitting out QPF just
northeast of our region, especially Friday night, but MOS PoPs are
mostly single digits. Won`t be surprised if we end up with some
PoPs Friday night or Saturday, but for now will just mention it
here and keep the forecast dry, and in line with neighboring
offices.
A literal handful of showers and one brief thunderstorm developed
across the forecast area yesterday afternoon. They were short-
lived, and with one exception, did not produce lightning. The 00Z
ARW and NMM WRF runs both generate some isolated convection across
the region this afternoon, and the latest HRRR shows some isolated
weak showers. With that support, will play the persistence card and
add isolated showers and storms to all but the far northwest and
western fringes of the area this afternoon. Will wait and see
what happens this afternoon before considering it for Friday
afternoon.
Temperatures climbed toward the warmer MAV/EC guidance yesterday
afternoon, so will continue to go that way with high temperatures
today and Friday. The 00Z MAV has 97 for Paducah Friday, but that
seems a bit spurious compared to surrounding MOS sites. Saturday
is a bit less clear cut, with the upper ridge weakening and
indications of a minor surge of surface high pressure over the
Evansville Tri State.
Stayed on the warm side of guidance Saturday over the Tri State,
but that does result in a couple of degrees of cooling from
Friday`s levels. Outside of the Tri State, Saturday could be just
as warm as Friday. The humidity is nothing like we had mid-summer,
but it could be just enough to allow heat indices to approach 100
in a few locations each afternoon.
Low temperatures tonight will be similar to this morning`s lows,
which are a bit lower than the consensus of guidance in most
locations. Lows Friday night may be closer to the consensus with
more wind expected.
.LONG TERM...(Saturday Night through Wednesday)
Issued at 327 AM CDT THU SEP 3 2015
The deterministic runs of the med range models have been somewhat
unstable of late, and the latest GFS 500 mb height spaghetti pattern
shows significantly increased chaos by Tue (Day 6), though the
latest GFS/ECMWF ensemble means appear quite similar overall. This
will affect confidence in the latter period forecast, regarding
impulses of energy in the nrn stream which may or may not produce a
secondary sfc front in our region.
Early in the extended period, the PAH forecast area will be affected
by an amplified srn stream pattern, with ridging aloft west of the
MS River and troffing over the Atlantic seaboard. Meanwhile, by Mon,
a cold front is progged to impinge on the ridge over our region.
There might be enough lift to produce a few showers and tstms in the
nwrn half of our region Mon afternoon, perhaps progressing a bit
farther sewd Mon night. The latest ECMWF appears to break down the
ridge more than the GFS by Tue, and is therefore more generous with
its QPF into Wed. For now, we downplayed PoPs a bit for Mon/Mon
night because of the lingering mid/upper ridge, then went generally
with the model initialization blend after that, which provided no
more than 40% PoPs for any 12 hour period. At this time, it appears
that model consensus and HPC point toward a bona fide sfc fropa at
the very end of the present Day 7 (Wed).
Expect above average temps through the extended period, slowly
decreasing by Day 7 to near seasonable levels.
&&
.AVIATION...
Issued at 1152 PM CDT WED SEP 2 2015
Little change from 00z Thursday TAF issuance. Main adjustment was
to reflect recent climatological visibility trends at KCGI, KEVV,
and KOWB. The lower visibility fog should be partial in coverage
and consist primarily of ground fog near each TAF site.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
SHORT TERM...DRS
LONG TERM...DB
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1152 PM CDT WED SEP 2 2015
.SHORT TERM...(This evening through Friday Night)
Issued at 218 PM CDT WED SEP 2 2015
Upper level disturbance in the lower Mississippi River Valley was
causing some isolated showers to our southwest this
afternoon...with a few cells getting fairly close to our SEMO
counties. The RUC and HRRR models seem to be overdone by showing
some activity developing over us this afternoon. Cu field looks
fairly shallow right now, but will continue to monitor for any
isolated development. The aforementioned upper level feature will
shift east tonight.
The 12Z model consensus continues to advertise high pressure at the
surface and aloft that will keep the area mainly dry through
Friday. The only exception to this may be on Thursday night into
Friday when some energy may drop south on the east side of the
upper high. Not every model is advertising any QPF and there
really isn`t too much moisture to work with other than a shallow
layer between 850-700mb. But an isolated or widely scattered storm
is possible. Too low of a probability to mention in the forecast
but would not be surprised to see a few cells out there.
Temperatures will remain above normal. Looks like low level temps
rise a degree or so for tomorrow and given the abundant
sunshine...believe we could be a tad warmer on Thursday. Some of the
guidance supports this notion as well. We could see temperatures
drop a degree or so in the eastern sections on Friday though as the
upper ridge breaks down a bit there. However, it will still be
fairly warm. Lower 90s for highs and upper 60s to around 70 degrees
for lows looks to be the norm for the next few days along with light
and variable winds.
.LONG TERM...(Saturday through Wednesday)
Issued at 218 PM CDT WED SEP 2 2015
Average confidence in the short term period due to model
differences, especially toward the end of the period. Very few
changes to the long term with not much to discuss.
At the beginning of the long term period, weak high pressure at the
surface and aloft will be the predominant features affecting our
CWA`s weather, therefore dry conditions are forecast for the first
couple of days.
Beyond that and through most of the long term period, the
development of weaknesses or slight shifting of the axis of the
aforementioned high pressure will make it possible for isolated to
scattered convection to pop up given the moisture and instability
already in place.
With the approach and passage of a cold front, precipitation chances
slowly increase and eventually overspread the entire CWA by the end
of the period.
Above normal temperatures at the beginning of the period will slowly
cool back to near normal readings by the end of the period.
&&
.AVIATION...
Issued at 1152 PM CDT WED SEP 2 2015
Little change from 00z Thursday TAF issuance. Main adjustment was
to reflect recent climatological visibility trends at KCGI, KEVV,
and KOWB. The lower visibility fog should be partial in coverage
and consist primarily of ground fog near each TAF site.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
454 AM EDT THU SEP 3 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 412 AM EDT THU SEP 3 2015
THE RAIN OVER THE SOUTHERN AND EASTERN PART OF THE FORECAST AREA
FINALLY SEEMS TO BE MOVING OUT OF THE AREA AS THE UPPER SHORT WAVE
MOVES EAST. THE BIG PROBLEM THIS MORNING IS ACTUALLY DENSE FOG
ACROSS THE WESTERN PART OF THE FORECAST AREA WHERE IT HAS CLEARED
OUT WITH SUFFICIENT LOW LEVEL MOISTURE FROM RAINFALL OVER THE PAST
24 HR. MOST OF THE WESTERN TIER OF COUNTIES HAVE VSBYS LESS THAN ONE
QUARTER OF A MILE AND AS SUCH HAVE OPTED TO GO WITH A DENSE FOG
ADVISORY FOR THIS AREA UNTIL 14Z.
OTHERWISE...AS THE UPPER SHORT WAVE SLOWLY MOVES EAST THIS
MORNING...EXPECT ANY REMAINING SHOWERS TO MOVE OUT OF THE AREA AS
WELL. THE RAP SUGGESTS THAT CYCLONIC FLOW WILL PERSIST THROUGH THE
DAY ACROSS THE EAST. THIS COMBINED WITH LAKE BREEZE CONVERGENCE
ACROSS THE EAST IMPLIES AT LEAST A SLIGHT CHANCE OF SHOWERS THIS
AFTERNOON ACROSS THE FAR EAST. NOT TOO EXCITED ABOUT THUNDERSTORM
CHANCES AS LOCAL RESEARCH SUGGESTS VERY MIMINAL THUNDERSTORM
DEVELOPMENT WITH NORTHERLY MID LEVEL FLOW. ACROSS THE REMAINDER OF
THE AREA...MINIMAL MLCAPE VALUES OF LESS THAN 300 J/KG PER THE
RAP...DRY AIR ASSOCIATED WITH THE HIGH PRES AND BUILDING HEIGHTS
SHOULD PRECLUDE ANY SHOWER/THUNDERSTORM DEVELOPMENT. DESPITE THE
NORTH-NORTHEAST FLOW...IT WILL STILL REMAIN MILD AND RATHER STICKY
WITH HIGHS IN THE UPPER 70S/LOWER 80S...STILL ABOVE NORMAL FOR EARLY
SEPTEMBER.
WITH HIGH PRESSURE IN CONTROL...IT SHOULD BE A QUIET NIGHT TONIGHT.
CANNOT RULE OUT MORE FOG DEVELOPMENT ACROSS THE INTERIOR WITH LIGHT
WINDS AND CLEAR SKIES. TEMPS SHOULD DROP INTO THE UPPER 50S/LOWER
60S.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 452 AM EDT THU SEP 3 2015
PRIME CONCERNS IN LONG TERM INCLUDE EXTENT/STRENGTH OF SHRA/TSRA
THIS WEEKEND INTO LABOR DAY AND MAX TEMPS. FOG WILL ALSO BE ISSUE
AT TIMES WITH HUMID AIRMASS PERSISTING UNTIL COLD FRONT ARRIVES BY
LABOR DAY.
UPPER RIDGE BUILDS BACK OVER UPPER GREAT LAKES ON FRIDAY. REMNANT OF
SHORTWAVE THAT IS MOVING THROUGH ATTM MEANDERS OVER LOWER MICHIGAN
AND MAY DRIFT TOWARD EAST CWA BY EVENING. GFS/NAM SOUNDINGS SEEM TOO
DRY FOR SHRA/TSRA WITH GENERAL EAST SFC WINDS COMING OUT OF HIGH
OVER QUEBEC. SLIGHTLY DRIER TOO WITH UPR 50S TO LOW 60S DWPNTS
INSTEAD OF UPR 60S-NEAR 70. COULD BE FOG AROUND TO START DAY BUT
THAT SHOULD GIVE WAY TO MOSTLY SUNNY SKIES BY LATE MORNING. TEMPS
HELD DOWN BY OVERALL FLOW OFF THE GREAT LAKES AND COOLER TEMPS
ALOFT. EXPECT MID 80S INTERIOR WEST AND UPR 70S NEAR 80 OVER REST OF
CWA.
EDGE OF UPPER RIDGE DRAWS CLOSE ENOUGH FRIDAY NIGHT INTO SATURDAY TO
BRING SHRA/TSRA POSSIBILITY BACK TO THE AREA...ADVECTING IN FM
NORTHERN PLAINS WITH SW MEAN LAYER H85-H3 WINDS. EDGE OF MUCAPE OVER
1000J/KG AS CLOSE AS NORTHERN MN AND NORTHERN WI. ECMWF AND GFS ALSO
BOTH SHOWING SHORTWAVE CURRENTLY OVER FOUR CORNERS TRACKING OVER
NORTHERN MN AND LK SUPERIOR BY 12Z SATURDAY. INCREASING H85 JET
RAMPS UP MOISTURE ADVECTION OVER MN SO HAVE PUT CHANCE POPS OVER
WESTERN LK SUPERIOR ON FRIDAY NIGHT AND SPREAD THEM INTO FAR WEST
CWA ON SATURDAY AS THERE MAY BE GREATER CHANCE OF SHRA/TSRA IN VCNTY
OF THE SHORTWAVE AND GIVEN THE HIGHER MUCAPES. MLCAPES ALSO PUSH UP
TOWARD 1000J/KG DURING AFTN SO THERE MAY BE ADDITIONAL SHRA/TSRA TRY
TO FORM DUE TO DAYTIME HEATING AND POSSIBLY AFFECTS FM THE
SHORTWAVE. PROBABLY WILL BE SOME FOG AROUND TO START DAY AGAIN. SE
WINDS ADDING MOISTURE OFF LK MICHIGAN AND RADIATIONAL COOLING FRIDAY
NIGHT SHOULD LEAD TO BEST BET FOR FOG OVER INTERIOR CNTRL AND NEAR
LK MICHIGAN. ONCE FOG EVADES...PARTLY SUNNY SKIES WILL ALLOW TEMPS
TO WARM QUITE A BIT OVER FRIDAY. H85 TEMPS PUSHING 19-20C BY AFTN
AND MORE OF A SOUTH WIND COMPARED TO FRIDAY POINT TO MID-UPR 80S FOR
MOST WITH A FEW 90 DEGREE READINGS POSSIBLE INTERIOR WEST AND NEAR
LK SUPERIOR WITH DOWNSLOPING WINDS.
STRONGER SHORTWAVE LIFTS OVER UPPER MISSISSIPPI RIVER VALLEY SAT
NIGHT IN SW FLOW ALOFT. AT SFC...LOW PRESSURE SYSTEM WILL BE
DEVELOPING OVER HIGH PLAINS WHILE TROUGHING EXTENDS ACROSS NORTHERN
PLAINS AND TO NORTHWEST ONTARIO. SOUTH WINDS AHEAD OF TROUGH SHOULD
LEAD TO WARM/MUGGY NIGHT OVER UPR MICHIGAN. MUCAPES REMAIN HIGH AT
1000-2000J/KG FM NORTHERN PLAINS ACROSS UPPER GREAT LAKES. IF
SHORTWAVE TRACKS CLOSE ENOUGH...COULD SEE SHRA/TSRA PUSH OVER WEST
HALF OF CWA AT LEAST WITH H85-H3 WINDS FM THE WSW. UNLIKE FRIDAY
NIGHT WITH SIMILAR SETUP...SHEAR IS FORECAST TO BE MUCH STRONGER AS
1-6KM SHEAR VALUES ARE 30-40 KTS. LOW-LEVEL JET AT H85 OVER 40 KTS
IS AIMED TOWARD UPPER MISSISSIPPI RIVER VALLEY AND AT LEAST WESTERN
FRINGE OF UPPER GREAT LAKES. NOT SURE IF GREATER MLCAPES WELL TO SW
OF HERE WILL KEEP MAIN SHRA/TSRA THERE SINCE THE SHORTWAVE IS MUCH
FARTHER NORTH. CARRIED CHANCE POPS OVER WEST CWA...SLIGHT CHANCES
FARTHER EAST. GIVEN THE SHEAR AND INSTABILITY...THERE IS AT LEAST A
REMOTE CHANCE OF STRONG TO SEVERE STORMS AS SHOWN BY LATEST DAY3
OUTLOOK FM SPC.
STRONG SHORTWAVE SLIDES FM ROCKIES TO THE NORTHERN PLAINS SUNDAY
INTO SUNDAY NIGHT. ASSOCIATED SFC LOW BOTTOMS OUT AT 990-1000MB OVER
SOUTHERN MANITOBA BY MONDAY MORNING. MOISTURE ADVECTION AND
CONTINUAL FEED OF STRONG INSTABILITY SHOULD SUPPORT MULTIPLE CLUSTERS
OF SHRA/TSRA WITHIN H85 JET AXIS AND JUST AHEAD OF SFC FRONT. NEVER
SURE HOW FAR SHRA/TSRA WILL BREAK OUT AHEAD OF MAIN FRONT AS WITHOUT
STRONG FORCING FM A YET TO BE DETERMINED SHORTWAVE THERE CAN ALWAYS
BE CAPPING CONCERNS. WILL CONTINUE TO HIGHLIGHT WEST CWA FOR BETTER
CHANCES AT THIS POINT WITH WSW MEAN LAYER WINDS. ANOTHER WARM AND
HUMID DAY AHEAD OF THE FRONT. H85 RIDGE AHEAD OF THE FRONT POINTS TO
READINGS SIMILAR TO SAT AS LONG AS CLOUDS/SHRA/TSRA DONT DISRUPT
THINGS TOO MUCH. PUT THE WARMEST TEMPS ON SUNDAY OVER CNTRL CWA
CLOSER TO LK SUPERIOR WITH DOWNSLOPING SOUTH WINDS. BEST CHANCE FOR
READINGS TO HIT 90 DEGREES WOULD BE BARAGA/BIG
BAY/MARQUETTE/HARVEY/MUNISING.
ALL THIS SHRA/TSRA ACTIVITY SHOULD EASE EAST ACROSS REST OF CWA AS
THE MAIN SFC-H85 FRONTS AND ASSOCIATED THETA-E RIDGE AND RIBBON OF
PWATS OVER 1.75 INCHES CROSS SUNDAY NIGHT INTO MONDAY. MLCAPES OVER
1000J/KG INITIALLY BUT THESE TAIL OFF WITH NIGHTTIME COOLING.
MUCAPES WELL OVER 1000J/KG MAY ALLOW STORMS TO TRY TO BECOME
ELEVATED AFTER BECOMING SFC BASED...BUT THAT IS ALWAYS A TRICKY
TRANSITION. STRONG H85 JET AND MOISTURE TRANSPORT INTO THE AREA
OF HIGHER MUCAPES WILL AID THIS TRANSITION THOUGH. CONSENSUS HIGH
CHANCE TO LOW-END LIKELY POPS SEEMED FINE FOR SUNDAY NIGHT. BETTER
POPS ON LABOR DAY END UP BEING OVER EAST HALF WITH GREATER MOISTURE
ADVECTION AHEAD OF THE EXITING SFC-H85 FRONT. H85 TEMPS DO NOT CRASH
DOWN AS IT LOOKED LIKE A FEW DAYS AGO...SO UPR 70S TO LOW OR
POSSIBLY MID 80S WILL WORK FOR TEMPS ON MONDAY. WARMEST READINGS
CNTRL CWA IRON MTN TO MARQUETTE AND MUNISING. THROUGH THE COOLING IS
NOT AS SIGNIFICANT...THE DRYING IS WITH DWPNTS FALLING OFF INTO THE
50S ON MONDAY AFTN OVER THE WEST AND DOWN TO AROUND 50 BY LATE
MONDAY NIGHT. COULD EVEN SEE 40S DWPNTS ON TUESDAY AS COOLING
BECOMES MORE PRONOUNCED. EXPECT HIGHS UPR 60S TO LOW 70S ON TUE AND
THEN MAINLY IN THE 60S FOR WED. GUSTY WINDS AS THE COOLING OCCURS
ESPECIALLY NEAR LK SUPERIOR. NEXT CHANCE OF RAIN PRETTY WELL AGREED
UPON BY GFS AND ECMWF FOR TUE NIGHT INTO WED MORNING.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 324 AM EDT THU SEP 3 2015
LIFR/VLIFR CONDITIONS IN FOG ARE EXPECTED AT KIWD/KCMX/KSAW
OVERNIGHT DUE TO WET GROUND FROM RECENT RAIN...LIGHT WINDS AND
CLOUDS THINNING OUT. FOG/STRATUS WILL CLEAR OUT WITHIN A FEW HRS
AFTER SUNRISE...LEADING TO VFR CONDITIONS THRU THE AFTN AT ALL
TERMINALS. MAY HAVE A RETURN OF SOME FOG TONIGHT...PROBABLY JUST
BEYOND THIS FCST PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 412 AM EDT THU SEP 3 2015
DENSE FOG HAS DEVELOPED ACROSS THE WESTERN HALF OF THE
LAKE...ESPECIALLY OVER AREAS THAT SAW RAIN YESTERDAY. AS SUCH...HAVE
ISSUED A DENSE FOG ADVY FOR THE ENTIRE WEST HALF OF THE LAKE THROUGH
EARLY THIS AFTERNOON. OTHERWISE...NORTHEAST WINDS OF 10-15KT WILL
CONTINUE TODAY WITH 1-3 FT WAVES ACROSS THE WEST. THE NEXT CHANCE
FOR WINDS GREATER THAN 20KT WILL BE SUNDAY INTO MONDAY AS THE NEXT
SYSTEM APPROACHES FROM THE WEST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
DENSE FOG ADVISORY UNTIL 10 AM EDT /9 AM CDT/ THIS MORNING FOR
MIZ001>003-009-084.
LAKE SUPERIOR...
DENSE FOG ADVISORY UNTIL 2 PM EDT /1 PM CDT/ THIS AFTERNOON FOR
LSZ162-240>248-263>265.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...MRD
LONG TERM...JLA
AVIATION...ROLFSON
MARINE...MRD
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
413 AM EDT THU SEP 3 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 412 AM EDT THU SEP 3 2015
THE RAIN OVER THE SOUTHERN AND EASTERN PART OF THE FORECAST AREA
FINALLY SEEMS TO BE MOVING OUT OF THE AREA AS THE UPPER SHORT WAVE
MOVES EAST. THE BIG PROBLEM THIS MORNING IS ACTUALLY DENSE FOG
ACROSS THE WESTERN PART OF THE FORECAST AREA WHERE IT HAS CLEARED
OUT WITH SUFFICIENT LOW LEVEL MOISTURE FROM RAINFALL OVER THE PAST
24 HR. MOST OF THE WESTERN TIER OF COUNTIES HAVE VSBYS LESS THAN ONE
QUARTER OF A MILE AND AS SUCH HAVE OPTED TO GO WITH A DENSE FOG
ADVISORY FOR THIS AREA UNTIL 14Z.
OTHERWISE...AS THE UPPER SHORT WAVE SLOWLY MOVES EAST THIS
MORNING...EXPECT ANY REMAINING SHOWERS TO MOVE OUT OF THE AREA AS
WELL. THE RAP SUGGESTS THAT CYCLONIC FLOW WILL PERSIST THROUGH THE
DAY ACROSS THE EAST. THIS COMBINED WITH LAKE BREEZE CONVERGENCE
ACROSS THE EAST IMPLIES AT LEAST A SLIGHT CHANCE OF SHOWERS THIS
AFTERNOON ACROSS THE FAR EAST. NOT TOO EXCITED ABOUT THUNDERSTORM
CHANCES AS LOCAL RESEARCH SUGGESTS VERY MIMINAL THUNDERSTORM
DEVELOPMENT WITH NORTHERLY MID LEVEL FLOW. ACROSS THE REMAINDER OF
THE AREA...MINIMAL MLCAPE VALUES OF LESS THAN 300 J/KG PER THE
RAP...DRY AIR ASSOCIATED WITH THE HIGH PRES AND BUILDING HEIGHTS
SHOULD PRECLUDE ANY SHOWER/THUNDERSTORM DEVELOPMENT. DESPITE THE
NORTH-NORTHEAST FLOW...IT WILL STILL REMAIN MILD AND RATHER STICKY
WITH HIGHS IN THE UPPER 70S/LOWER 80S...STILL ABOVE NORMAL FOR EARLY
SEPTEMBER.
WITH HIGH PRESSURE IN CONTROL...IT SHOULD BE A QUIET NIGHT TONIGHT.
CANNOT RULE OUT MORE FOG DEVELOPMENT ACROSS THE INTERIOR WITH LIGHT
WINDS AND CLEAR SKIES. TEMPS SHOULD DROP INTO THE UPPER 50S/LOWER
60S.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 318 PM EDT WED SEP 2 2015
SPENT MOST TIME HELPING WITH SHORT TERM WARNING OPERATIONS...SO
RELIED HEAVILY ON PREVIOUS FORECAST AND CONSENSUS FOR THE LONG TERM
FORECAST.
OVERALL...EXPECT A SOME LOW END SHOWER AND THUNDERSTORM CHANCES IN
THE REGION FRI AND SAT AS THE UPPER RIDGE SITS OVER THE AREA WITH
SHORTWAVES PUSHING THROUGH THE RIDGE. A LOW PRESSURE SYSTEM WILL
MOVE FROM THE INTER-MOUNTAIN WEST LATE SAT TO HUDSON BAY BY
TUE...BRINGING INCREASED SHOWER AND THUNDERSTORM CHANCES SUN THROUGH
MON AS A COLD FRONT MOVES ACROSS. THE PROLONGED HEAT WILL GIVE WAY
TO COOLER TEMPS EARLY NEXT WEEK WHEN HIGH TEMPS WILL DROP DOWN
CLOSER TO NORMAL IN THE 60S AND 70S. ANOTHER SYSTEM MAY MOVE THROUGH
NEXT WED...POSSIBLY BRINGING PRECIP TO MUCH OF THE AREA...BUT
PREDICTABILITY IS LOW WITH THIS SYSTEM.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 324 AM EDT THU SEP 3 2015
LIFR/VLIFR CONDITIONS IN FOG ARE EXPECTED AT KIWD/KCMX/KSAW
OVERNIGHT DUE TO WET GROUND FROM RECENT RAIN...LIGHT WINDS AND
CLOUDS THINNING OUT. FOG/STRATUS WILL CLEAR OUT WITHIN A FEW HRS
AFTER SUNRISE...LEADING TO VFR CONDITIONS THRU THE AFTN AT ALL
TERMINALS. MAY HAVE A RETURN OF SOME FOG TONIGHT...PROBABLY JUST
BEYOND THIS FCST PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 412 AM EDT THU SEP 3 2015
DENSE FOG HAS DEVELOPED ACROSS THE WESTERN HALF OF THE
LAKE...ESPECIALLY OVER AREAS THAT SAW RAIN YESTERDAY. AS SUCH...HAVE
ISSUED A DENSE FOG ADVY FOR THE ENTIRE WEST HALF OF THE LAKE THROUGH
EARLY THIS AFTERNOON. OTHERWISE...NORTHEAST WINDS OF 10-15KT WILL
CONTINUE TODAY WITH 1-3 FT WAVES ACROSS THE WEST. THE NEXT CHANCE
FOR WINDS GREATER THAN 20KT WILL BE SUNDAY INTO MONDAY AS THE NEXT
SYSTEM APPROACHES FROM THE WEST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
DENSE FOG ADVISORY UNTIL 10 AM EDT /9 AM CDT/ THIS MORNING FOR
MIZ001>003-009-084.
LAKE SUPERIOR...
DENSE FOG ADVISORY UNTIL 2 PM EDT /1 PM CDT/ THIS AFTERNOON FOR
LSZ162-240>248-263>265.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...MRD
LONG TERM...TITUS
AVIATION...ROLFSON
MARINE...MRD
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1151 PM CDT WED SEP 2 2015
.SYNOPSIS...
ISSUED AT 322 PM CDT WED SEP 2 2015
H5 ANALYSIS THIS MORNING HAD LOW PRESSURE OVER WEST
CENTRAL PORTIONS OF BRITISH COLUMBIA WITH A TROUGH EXTENDING TO THE
SOUTHWEST INTO THE NERN PACIFIC. SOUTH OF THE LOW 50 TO 60 METER HT
FALLS WERE NOTED OVER OREGON AND WASHINGTION STATE WITH A 50 KT JET
STREAK COLLOCATED WITH THE HT FALLS. EAST OF THE LOW...BROAD WEST
SOUTHWESTERLY FLOW EXTENDED ACROSS THE NRN TIER OF STATES AND SRN
CANADA. SOUTH OF THE LOW AND JET STREAK...TWO SHORTWAVES WERE
NOTED...ONE NEAR LAS VEGAS AND A SECOND OFF THE COAST OF SRN
CALIFORNIA. AT THE SURFACE...A TROUGH OF LOW PRESSURE EXTENDED FROM
NORTH CENTRAL NEBRASKA INTO SWRN KS THIS AFTERNOON. WINDS BEHIND
THIS FEATURE WERE FROM THE WEST AT UNDER 10 MPH...WHILE EAST OF THIS
FEATURE...WINDS WERE FROM THE SOUTH AT AROUND 10 MPH. TEMPERATURES
AS OF 3 PM CDT RANGED FROM 95 AT ONEILL...TO 100 AT VALENTINE.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 322 PM CDT WED SEP 2 2015
WEAK UPPER HEIGHT RISES ONGOING ACROSS THE AREA AS CENTRAL PLAINS
RIDGE BUILDS IN RESPONSE TO DEEPENING TROUGH ACROSS THE PAC NW.
THE SFC REFLECTION TO THIS IS A WEAK SFC TROUGH ACROSS THE MIDDLE
OF THE WESTERN HALF OF NEB...THOUGH WINDS ARE LIGHT MOST
LOCATIONS. MOST NOTABLE DIFFERENCE ACROSS THE ARE ARE DEW POINT
TEMPS WHICH HAVE DROPPED INTO THE UPPER 40S FROM VTN TO OGA...WITH
MID 60S HANGING ON FROM BBW TO ONL AT THIS HOUR. LOW LEVEL
MOISTURE NOT MIXING OUT AS FAR EAST AS THE NAM SUGGESTED...AND FAR
FROM WHAT THE GFS HAD WHICH IS A KNOWN ISSUE WITH THE GFS. DRY
LINE WILL RETREAT WWD AFTER SUNSET UNDER MAINLY CLEAR SKIES.
OPERATIONAL HRRR AND RAP DEVELOPING A SMALL AREA OF CONVECTIVE
PRECIP LATE THIS AFTERNOON AS WEAK FORCING ALOFT OVERLAYS THE DRY
LINE BOUNDARY. SHORT TERM FCST SOUNDINGS FROM THE HRRR AND RAP
SHOW PRONOUNCED INVERTED V PROFILE WITH VERY LITTLE CAPE ABOVE THE
LFC. HAVE NOT INCLUDED MENTION OF PRECIP NOR QPF THIS EVENING WITH
THE IDEA THAT DRY AIR ENTRAINMENT WILL INHIBIT THE POTENTIAL FOR
DEEP...MOIST CONVECTION SUFFICIENT FOR PRECIP.
AS FLOW BECOMES MORE MERIDIONAL WITH THE DEEPENING UPPER TROUGH IN
THE NW...NEXT PV ANOMALY AND ASSOCIATED PUSH OF MID AND UPPER LEVEL
MOISTURE WILL ROTATE NWD OUT OF THE SWRN UNITED STATES. THIS SHOULD
ALLOW FOR MORE SHOWER AND THUNDERSTORM DEVELOPMENT OVER THE HIGHER
TERRAIN FURTHER WEST WHICH WILL MOVE INTO THE WESTERN PORTIONS OF
THE AREA BY LATE AFTERNOON THURSDAY. SOME LARGE SCALE HEIGHT FALLS
ASSOCIATED WITH THIS FEATURE WILL ALLOW FOR SLIGHT COOLING OF THE
UPPER LEVELS AND WHEN PAIRED WITH SOMEWHAT DEEPER MOISTURE WITH
SERLY SFC WINDS...WILL BE SUFFICIENT FOR POSITIVE CAPE ABOVE THE
LOWER LFC BY LATE IN THE DAY. WEAK SHEAR REMAINS HOWEVER SO ALTHOUGH
BETTER CHANCES EXIST FOR THUNDERSTORMS...LARGE SCALE ORGANIZATION
DOES NOT LOOK FAVORABLE THROUGH 00Z FRI. THE ADDED MID AND UPPER
LEVEL MOISTURE AND ASSOCIATED CLOUDS WITH CONVECTION IN SWRLY
FLOW...WHICH HAS ORIGINS IN THE TROPICS ACCORDING TO ANALYSIS OF
320K MIXING RATIO...WILL ALLOW SLIGHTLY COOLER MAX TEMPS FOR
THURSDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 322 PM CDT WED SEP 2 2015
THURSDAY NIGHT THROUGH SATURDAY NIGHT...IN THE MID RANGE...THE MAIN
FORECASTING CHALLENGES ARE PRECIPITATION CHANCES THURSDAY NIGHT...AND
AGAIN ON FRIDAY NIGHT INTO SATURDAY. FOR THURSDAY
NIGHT...THUNDERSTORMS WILL BE ONGOING ACROSS SWRN NEBR AND NERN
COLORADO AT THE BEGINNING OF THE PERIOD. THIS ACTIVITY WILL MOVE
NORTHEAST INTO THE NIGHTTIME HOURS THANKS TO DECENT MID LEVEL
WAA...WHICH TRACKS FROM SOUTHWESTERN INTO NORTH CENTRAL NEBRASKA. IN
ADDITION...THE NOSE OF A H85 JET STREAK WILL TRACK FROM SOUTH
CENTRAL INTO EASTERN NEBRASKA OVERNIGHT...ADDING ADDTL SUPPORT FOR
PRECIPITATION. AS FOR CHANCES...DECIDED TO KEEP THESE ON THE LOWER
SIDE OF THE ENVELOP AS TIME SECTIONS ARE INDICATIVE OF A DECENT DRY
LAYER BELOW 10000 FT AGL WHICH WILL LIMIT COVERAGE AS WELL AS QPF/S.
ON FRIDAY...STORMS WILL LINGER INTO THE MORNING HOURS ACROSS NERN
PORTIONS OF THE FORECAST AREA. BY AFTERNOON...TRANQUIL WEATHER CONDS
ARE EXPECTED AS THE FORECAST AREA IS IN BETWEEN SYSTEMS. SLIGHTLY
DRIER AIR WILL PUSH INTO THE NORTHWESTERN CWA FRIDAY WITH A DRYLINE
EXTENDING FROM NORTH CENTRAL INTO SWRN NEBRASKA. UPPER LEVEL FORCING
WILL HOLD OFF UNTIL FRIDAY AFTERNOON...SO MOST LOCATIONS WILL SEE A
DRY FCST ON FRIDAY. PCPN CHANCES WILL BEGIN TO INCREASE FRIDAY
EVENING AS A STRONG UPPER LEVEL DISTURBANCE LIFTS ACROSS EASTERN
COLORADO...APPG WESTERN NEBRASKA FRIDAY EVENING. THE BEFORE
MENTIONED DRYLINE WILL RETREAT WEST DURING THE EVENING HRS. HOW FAR
WEST THIS RETREATS AND THE AMOUNT OF DEEP LAYER MOISTURE AVAILABLE
FRIDAY NIGHT IS SOMEWHAT IN DOUBT ATTM. THE GFS IS MUCH DRIER IN THE
WEST COMPARED TO THE NAM SOLN. IN FACT...LAYER PW/S ARE RUNNING
AROUND A HALF AN INCH DRIER IN THE GFS COMPARED TO THE NAM SOLN. NO
SURPRISE...THE GFS IS DRY WITH ITS QPF FIELD FRIDAY NIGHT AND THE
NAM DEVELOPS CONVECTION INVOF THE DRYLINE. INHERITED FCST HAD A
MENTION OF PCPN FRIDAY NIGHT...AND WITH THE GFS BEING TOO DRY IN ITS
LOWER LEVELS UPON INITIALIZATION THIS MORNING...LEANED TOWARD THE
WETTER NAM SOLN WHICH SEEMED TO DO BETTER WITH THE MOISTURE FIELD.
THAT BEING SAID...PRECIPITATION CHANCES IN THE 20 TO 30 PERCENT
RANGE SEEM PLAUSIBLE FOR NOW. THE THREAT FOR PCPN WILL LINGER INTO
SATURDAY IN THE NORTH DURING THE MORNING HOURS...THEN WITH POSSIBLE
DEVELOPMENT OVER EASTERN AND CENTRAL NEBRASKA SATURDAY AFTERNOON. AS
FOR DEVELOPMENT SATURDAY AFTERNOON...ONCE AGAIN...THE GFS SEEMS TOO
DRY WITH ITS MOISTURE FIELD AND CONTINUE TO LEAN TOWARD THE WETTER
NAM SOLN WHICH INITIATES A LINE OF CONVECTION ACROSS THE CENTRAL AND
EASTERN CWA SAT AFTN. DEEP LAYER WIND SHEAR FINALLY REACHES 30 TO 40
KTS SAT AFTN...SO WOULDN/T BE SURPRISED IF A STRONG TO SEVERE STORM
DEVELOPS SAT AFTN/EVE.
SUNDAY THROUGH WEDNESDAY...IN THE EXTENDED...A STRONG UPPER LEVEL
LOW WILL TRACK ACROSS THE NORTHERN ROCKIES INTO SOUTH CENTRAL CANADA
SUNDAY INTO MONDAY. ON SUNDAY...A PREFRONTAL TROUGH WILL PUSH
THROUGH MOST OF THE FORECAST AREA...FORCING LOW LEVEL MOISTURE INTO
CENTRAL AND EASTERN NEBRASKA. FOR THE BULK OF THE FORECAST
AREA...SUNDAY AND SUNDAY NIGHT WILL BE DRY...HOWEVER...LOCATIONS IN
THE FAR NORTHEASTERN CWA WILL SEE A SLIGHT CHANCE FOR RAIN SUNDAY
AFTERNOON/NIGHT. ON SUNDAY NIGHT...A STRONG COLD FRONT WILL PASS
THROUGH THE FORECAST AREA...AND FOR THE MOST PART...WILL BE A DRY
FROPA WITH THE EXCEPTION OF THE FAR EASTERN CWA WHERE SOME LIMITED
MOISTURE WILL REMAIN IN PLACE. THE FRONT WILL THEN STALL ACROSS FAR
SRN NEBRASKA MONDAY...THEN LIFT NORTH MONDAY NIGHT INTO TUESDAY AS A
SECOND UPPER LEVEL WAVE DEVELOPS OVER THE NRN ROCKIES. WITH THE
FRONTAL BOUNDARY DRAPED ACROSS THE FORECAST AREA TUESDAY INTO
WEDNESDAY...WENT AHEAD AND LEFT IN A MENTION OF PCPN. TEMPERATURES
BEHIND THE FRONT MONDAY...TUESDAY AND WEDNESDAY WILL GENERALLY BE IN
THE 70S TO LOWER 80S WHICH IS RIGHT AT SEASONAL FOR EARLY
SEPTEMBER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1147 PM CDT WED SEP 2 2015
UNLIMITED CEILING AND VISIBILITY ARE FORECAST TONIGHT...THURSDAY
AND THURSDAY AFTERNOON. SOUTHEAST WIND 5 TO 10 MPH TONIGHT WILL
INCREASE TO 12-14KT AND BECOME MORE SOUTH EARLY THURSDAY
AFTERNOON.
THE EVENING MODEL RUNS ARE SHOWING THUNDERSTORMS THURSDAY EVENING
AS A WEAK FRONT MAKES ITS WAY INTO WESTERN NEBRASKA. WEST OF VTN...
LBF...TIF AND CROSSING INTO CENTRAL NEBRASKA AFTER 06Z.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CLB
SHORT TERM...JWS
LONG TERM...CLB
AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1106 PM CDT WED SEP 2 2015
.SYNOPSIS...
ISSUED AT 322 PM CDT WED SEP 2 2015
H5 ANALYSIS THIS MORNING HAD LOW PRESSURE OVER WEST
CENTRAL PORTIONS OF BRITISH COLUMBIA WITH A TROUGH EXTENDING TO THE
SOUTHWEST INTO THE NERN PACIFIC. SOUTH OF THE LOW 50 TO 60 METER HT
FALLS WERE NOTED OVER OREGON AND WASHINGTION STATE WITH A 50 KT JET
STREAK COLLOCATED WITH THE HT FALLS. EAST OF THE LOW...BROAD WEST
SOUTHWESTERLY FLOW EXTENDED ACROSS THE NRN TIER OF STATES AND SRN
CANADA. SOUTH OF THE LOW AND JET STREAK...TWO SHORTWAVES WERE
NOTED...ONE NEAR LAS VEGAS AND A SECOND OFF THE COAST OF SRN
CALIFORNIA. AT THE SURFACE...A TROUGH OF LOW PRESSURE EXTENDED FROM
NORTH CENTRAL NEBRASKA INTO SWRN KS THIS AFTERNOON. WINDS BEHIND
THIS FEATURE WERE FROM THE WEST AT UNDER 10 MPH...WHILE EAST OF THIS
FEATURE...WINDS WERE FROM THE SOUTH AT AROUND 10 MPH. TEMPERATURES
AS OF 3 PM CDT RANGED FROM 95 AT ONEILL...TO 100 AT VALENTINE.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 322 PM CDT WED SEP 2 2015
WEAK UPPER HEIGHT RISES ONGOING ACROSS THE AREA AS CENTRAL PLAINS
RIDGE BUILDS IN RESPONSE TO DEEPENING TROUGH ACROSS THE PAC NW.
THE SFC REFLECTION TO THIS IS A WEAK SFC TROUGH ACROSS THE MIDDLE
OF THE WESTERN HALF OF NEB...THOUGH WINDS ARE LIGHT MOST
LOCATIONS. MOST NOTABLE DIFFERENCE ACROSS THE ARE ARE DEW POINT
TEMPS WHICH HAVE DROPPED INTO THE UPPER 40S FROM VTN TO OGA...WITH
MID 60S HANGING ON FROM BBW TO ONL AT THIS HOUR. LOW LEVEL
MOISTURE NOT MIXING OUT AS FAR EAST AS THE NAM SUGGESTED...AND FAR
FROM WHAT THE GFS HAD WHICH IS A KNOWN ISSUE WITH THE GFS. DRY
LINE WILL RETREAT WWD AFTER SUNSET UNDER MAINLY CLEAR SKIES.
OPERATIONAL HRRR AND RAP DEVELOPING A SMALL AREA OF CONVECTIVE
PRECIP LATE THIS AFTERNOON AS WEAK FORCING ALOFT OVERLAYS THE DRY
LINE BOUNDARY. SHORT TERM FCST SOUNDINGS FROM THE HRRR AND RAP
SHOW PRONOUNCED INVERTED V PROFILE WITH VERY LITTLE CAPE ABOVE THE
LFC. HAVE NOT INCLUDED MENTION OF PRECIP NOR QPF THIS EVENING WITH
THE IDEA THAT DRY AIR ENTRAINMENT WILL INHIBIT THE POTENTIAL FOR
DEEP...MOIST CONVECTION SUFFICIENT FOR PRECIP.
AS FLOW BECOMES MORE MERIDIONAL WITH THE DEEPENING UPPER TROUGH IN
THE NW...NEXT PV ANOMALY AND ASSOCIATED PUSH OF MID AND UPPER LEVEL
MOISTURE WILL ROTATE NWD OUT OF THE SWRN UNITED STATES. THIS SHOULD
ALLOW FOR MORE SHOWER AND THUNDERSTORM DEVELOPMENT OVER THE HIGHER
TERRAIN FURTHER WEST WHICH WILL MOVE INTO THE WESTERN PORTIONS OF
THE AREA BY LATE AFTERNOON THURSDAY. SOME LARGE SCALE HEIGHT FALLS
ASSOCIATED WITH THIS FEATURE WILL ALLOW FOR SLIGHT COOLING OF THE
UPPER LEVELS AND WHEN PAIRED WITH SOMEWHAT DEEPER MOISTURE WITH
SERLY SFC WINDS...WILL BE SUFFICIENT FOR POSITIVE CAPE ABOVE THE
LOWER LFC BY LATE IN THE DAY. WEAK SHEAR REMAINS HOWEVER SO ALTHOUGH
BETTER CHANCES EXIST FOR THUNDERSTORMS...LARGE SCALE ORGANIZATION
DOES NOT LOOK FAVORABLE THROUGH 00Z FRI. THE ADDED MID AND UPPER
LEVEL MOISTURE AND ASSOCIATED CLOUDS WITH CONVECTION IN SWRLY
FLOW...WHICH HAS ORIGINS IN THE TROPICS ACCORDING TO ANALYSIS OF
320K MIXING RATIO...WILL ALLOW SLIGHTLY COOLER MAX TEMPS FOR
THURSDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 322 PM CDT WED SEP 2 2015
THURSDAY NIGHT THROUGH SATURDAY NIGHT...IN THE MID RANGE...THE MAIN
FORECASTING CHALLENGES ARE PRECIPITATION CHANCES THURSDAY NIGHT...AND
AGAIN ON FRIDAY NIGHT INTO SATURDAY. FOR THURSDAY
NIGHT...THUNDERSTORMS WILL BE ONGOING ACROSS SWRN NEBR AND NERN
COLORADO AT THE BEGINNING OF THE PERIOD. THIS ACTIVITY WILL MOVE
NORTHEAST INTO THE NIGHTTIME HOURS THANKS TO DECENT MID LEVEL
WAA...WHICH TRACKS FROM SOUTHWESTERN INTO NORTH CENTRAL NEBRASKA. IN
ADDITION...THE NOSE OF A H85 JET STREAK WILL TRACK FROM SOUTH
CENTRAL INTO EASTERN NEBRASKA OVERNIGHT...ADDING ADDTL SUPPORT FOR
PRECIPITATION. AS FOR CHANCES...DECIDED TO KEEP THESE ON THE LOWER
SIDE OF THE ENVELOP AS TIME SECTIONS ARE INDICATIVE OF A DECENT DRY
LAYER BELOW 10000 FT AGL WHICH WILL LIMIT COVERAGE AS WELL AS QPF/S.
ON FRIDAY...STORMS WILL LINGER INTO THE MORNING HOURS ACROSS NERN
PORTIONS OF THE FORECAST AREA. BY AFTERNOON...TRANQUIL WEATHER CONDS
ARE EXPECTED AS THE FORECAST AREA IS IN BETWEEN SYSTEMS. SLIGHTLY
DRIER AIR WILL PUSH INTO THE NORTHWESTERN CWA FRIDAY WITH A DRYLINE
EXTENDING FROM NORTH CENTRAL INTO SWRN NEBRASKA. UPPER LEVEL FORCING
WILL HOLD OFF UNTIL FRIDAY AFTERNOON...SO MOST LOCATIONS WILL SEE A
DRY FCST ON FRIDAY. PCPN CHANCES WILL BEGIN TO INCREASE FRIDAY
EVENING AS A STRONG UPPER LEVEL DISTURBANCE LIFTS ACROSS EASTERN
COLORADO...APPG WESTERN NEBRASKA FRIDAY EVENING. THE BEFORE
MENTIONED DRYLINE WILL RETREAT WEST DURING THE EVENING HRS. HOW FAR
WEST THIS RETREATS AND THE AMOUNT OF DEEP LAYER MOISTURE AVAILABLE
FRIDAY NIGHT IS SOMEWHAT IN DOUBT ATTM. THE GFS IS MUCH DRIER IN THE
WEST COMPARED TO THE NAM SOLN. IN FACT...LAYER PW/S ARE RUNNING
AROUND A HALF AN INCH DRIER IN THE GFS COMPARED TO THE NAM SOLN. NO
SURPRISE...THE GFS IS DRY WITH ITS QPF FIELD FRIDAY NIGHT AND THE
NAM DEVELOPS CONVECTION INVOF THE DRYLINE. INHERITED FCST HAD A
MENTION OF PCPN FRIDAY NIGHT...AND WITH THE GFS BEING TOO DRY IN ITS
LOWER LEVELS UPON INITIALIZATION THIS MORNING...LEANED TOWARD THE
WETTER NAM SOLN WHICH SEEMED TO DO BETTER WITH THE MOISTURE FIELD.
THAT BEING SAID...PRECIPITATION CHANCES IN THE 20 TO 30 PERCENT
RANGE SEEM PLAUSIBLE FOR NOW. THE THREAT FOR PCPN WILL LINGER INTO
SATURDAY IN THE NORTH DURING THE MORNING HOURS...THEN WITH POSSIBLE
DEVELOPMENT OVER EASTERN AND CENTRAL NEBRASKA SATURDAY AFTERNOON. AS
FOR DEVELOPMENT SATURDAY AFTERNOON...ONCE AGAIN...THE GFS SEEMS TOO
DRY WITH ITS MOISTURE FIELD AND CONTINUE TO LEAN TOWARD THE WETTER
NAM SOLN WHICH INITIATES A LINE OF CONVECTION ACROSS THE CENTRAL AND
EASTERN CWA SAT AFTN. DEEP LAYER WIND SHEAR FINALLY REACHES 30 TO 40
KTS SAT AFTN...SO WOULDN/T BE SURPRISED IF A STRONG TO SEVERE STORM
DEVELOPS SAT AFTN/EVE.
SUNDAY THROUGH WEDNESDAY...IN THE EXTENDED...A STRONG UPPER LEVEL
LOW WILL TRACK ACROSS THE NORTHERN ROCKIES INTO SOUTH CENTRAL CANADA
SUNDAY INTO MONDAY. ON SUNDAY...A PREFRONTAL TROUGH WILL PUSH
THROUGH MOST OF THE FORECAST AREA...FORCING LOW LEVEL MOISTURE INTO
CENTRAL AND EASTERN NEBRASKA. FOR THE BULK OF THE FORECAST
AREA...SUNDAY AND SUNDAY NIGHT WILL BE DRY...HOWEVER...LOCATIONS IN
THE FAR NORTHEASTERN CWA WILL SEE A SLIGHT CHANCE FOR RAIN SUNDAY
AFTERNOON/NIGHT. ON SUNDAY NIGHT...A STRONG COLD FRONT WILL PASS
THROUGH THE FORECAST AREA...AND FOR THE MOST PART...WILL BE A DRY
FROPA WITH THE EXCEPTION OF THE FAR EASTERN CWA WHERE SOME LIMITED
MOISTURE WILL REMAIN IN PLACE. THE FRONT WILL THEN STALL ACROSS FAR
SRN NEBRASKA MONDAY...THEN LIFT NORTH MONDAY NIGHT INTO TUESDAY AS A
SECOND UPPER LEVEL WAVE DEVELOPS OVER THE NRN ROCKIES. WITH THE
FRONTAL BOUNDARY DRAPED ACROSS THE FORECAST AREA TUESDAY INTO
WEDNESDAY...WENT AHEAD AND LEFT IN A MENTION OF PCPN. TEMPERATURES
BEHIND THE FRONT MONDAY...TUESDAY AND WEDNESDAY WILL GENERALLY BE IN
THE 70S TO LOWER 80S WHICH IS RIGHT AT SEASONAL FOR EARLY
SEPTEMBER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1104 PM CDT WED SEP 2 2015
UNLIMITED CEILING AND VISIBILITY ARE FORECAST TONIGHT...THURSDAY
AND THURSDAY EVENING. SOUTHEAST WIND 5 TO 10 MPH TONIGHT WILL
INCREASE TO 12-14KT AND BECOME MORE SOUTH EARLY THURSDAY
AFTERNOON.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CLB
SHORT TERM...JWS
LONG TERM...CLB
AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
326 AM EDT THU SEP 3 2015
.SYNOPSIS...
ABOVE NORMAL TEMPERATURES ARE EXPECTED TODAY THROUGH FRIDAY. A WEAK
TROUGH WILL LINGER IN THE AREA THROUGH EARLY FRIDAY. A RIDGE OF HIGH
PRESSURE WILL BUILD IN FROM THE NORTH BEHIND A COLD FRONT THIS
WEEKEND...BRINGING UNSETTLED WEATHER AND COOLER TEMPERATURES THROUGH
THE FIRST PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 330 AM THURSDAY...GUST FRONT FROM CONVECTION UP NORTH
MOVING THROUGH OUR NORTH CAROLINA COUNTIES AT THIS TIME. WINDS ARE
NOT STRONG...BUT AT 5 TO 10 KTS ARE CREATING A NOTICEABLE WIND
SHIFT. ASSOCIATED CONVECTION STILL TO OUR NORTH BUT MAY SCRAPE
PENDER COUNTY BEFORE MOVING OFFSHORE.
WEAK PRESSURE PATTERN AND ABOVE-NORMAL TEMPERATURES CONTINUE FOR
ANOTHER DAY. PIEDMONT-STYLE THERMAL TROUGH TO OUR WEST STRENGTHENS
TODAY AND ALSO EXPECT THE DIURNALLY DRIVEN SEA BREEZE CIRCULATION TO
SET UP THIS AFTERNOON. A MODERATELY UNSTABLE COLUMN WILL DEVELOP
THIS AFTERNOON AND WITH PLENTIFUL AVAILABLE MOISTURE...WITH P/W
VALUES CLOSING IN ON 2 INCHES...STILL EXPECTING SCATTERED CONVECTION
TO DEVELOP. INITIAL FOCUS OF CONVECTION...FOR LACK OF AN OTHER
STRONG TRIGGERS...WILL BE ALONG THE SEA BREEZE FRONT THIS AFTERNOON.
DIURNALLY DRIVEN CONVECTION WILL FADE WITH THE SUNSET.
ABOVE NORMAL TEMPERATURES WILL CONTINUE AND WITH DEWPOINTS RANGING
FROM THE UPPER 60S TO MID 70S EXPECT APPARENT TEMPERATURES TO PEAK
AT AROUND 100 DEGREES THIS AFTERNOON. OVERNIGHT MINIMUMS PROJECTED
IN THE LOWER TO MID 70S.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 230 AM THURSDAY...H5 RIDGE AXIS IS SHOWN TO EXTEND FROM THE
SOUTHERN PLAINS AND LOWER MS VALLEY INTO THE MID WEST AND GREAT
LAKES REGION EARLY FRIDAY WITH A WEAK TROUGH ORIENTED NEARLY EAST-
WEST FROM THE MID-ATLANTIC REGION TOWARD THE OHIO VALLEY. THE H5
TROUGH WILL DRIFT SOUTH ACROSS THE SOUTHEASTERN STATES WITH SOME
DURING SATURDAY AS HIGH PRESSURE ALOFT EVOLVES ACROSS NEW ENGLAND.
AT THE SURFACE...A RIDGE WILL BUILD SOUTH ACROSS THE FORECAST AREA
FRIDAY NIGHT INTO SATURDAY BRINGING AN END TO THE ATYPICALLY WARM
TEMPERATURES. THE PRECIPITABLE WATER DOES NOT STAND OUT AS IT IS
EXPECTED TO AVERAGE A LITTLE OVER AN INCH AND A HALF EACH DAY. AN
INCREASE IN LOW-LEVEL CONVERGENCE ON SATURDAY IN NORTHEASTERLY FLOW
TRANSLATES TO SLIGHTLY HIGHER POPS COMPARED TO FRIDAY IN AN
ENVIRONMENT THAT IS UNSETTLED...BUT DEVOID OF A SIGNIFICANT LIFTING
MECHANISM.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 230 AM THURSDAY...WEAK/BROAD AREA OF LOW PRESSURE NOTED IN
500MB PROGS WILL LINGER OVER THE SOUTHEAST UNITED STATES SUNDAY
RESULTING IN A CONTINUATION OF UNSETTLED WEATHER THROUGH TUESDAY AS
IT GRADUALLY WEAKENS OVER THE REGION. THE SURFACE RIDGE WEAKENS
ACROSS THE CAROLINAS AS WELL DURING THE PERIOD WITH LOWER PRESSURE
LINGERING OFF THE COAST. ALTHOUGH THE PRECIPITABLE WATER IS EXPECTED
TO INCREASE TO JUST UNDER TWO INCHES BY MONDAY THE HIGHEST
PRECIPITABLE WATER WILL CONTINUE TO BE SUPPRESSED OFFSHORE TO THE
SOUTHEAST AND SOUTH OF THE AREA. EXPECTING SCATTERED SHOWERS AND A
FEW TSTMS EACH DAY WITH THE BEST CHANCES MONDAY COINCIDENT WITH THE
HIGHEST PRECIPITABLE WATER. MAX TEMPERATURES EACH DAY WILL RANGE
WITHIN A COUPLE DEGREES OF CLIMATOLOGY WHILE THE MINS REMAIN A
COUPLE CATEGORIES ABOVE NORMAL.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
AS OF 06Z...THE HRRR MODEL HAS BEEN FAIRLY CONSISTENT IN BRINGING
SOME CONVECTION FROM THE NORTHWEST...ASSOCIATED WITH A MODERATE
VORT MAX DROPPING IN FROM VIRGINIA. THE CONVECTION WILL LIKELY
DISSIPATE BY 10-11Z AS IT MOVES OFF THE COAST OF SOUTHEAST NORTH
CAROLINA. THIS IS MAINLY LEANING ON THE NAM MODEL AS THE GFS
SHIFTS THE PRECIP OFFSHORE BEFORE IT GETS HERE. TOOK OUT THE TEMPO
LOWER FOG AT LBT AS THERE WILL LIKELY BE TOO MANY CLOUDS TO
RADIATE EFFECTIVELY. THURSDAY...ANOTHER HOT DAY WITH WEST
NORTHWEST FLOW. SOME SCATTERED CONVECTION MAY DEVELOP AROUND MAX
HEATING...ESPECIALLY ALONG THE RESULTANT.
EXTENDED OUTLOOK...PREDOMINATELY VFR WITH BRIEF MORNING FOG AND
ISOLATED/SCATTERED AFTERNOON SHOWERS AND THUNDERSTORMS.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 330 AM THURSDAY...A WEAK PRESSURE PATTERN OVER THE WESTERN
ATLANTIC WILL MAINTAIN A WESTERLY FLOW OF 10 KTS OVER THE COASTAL
WATERS EARLY TODAY...INCREASING TO 10 TO 15 KTS WITH HIGHER GUSTS
NEAR SHORE THIS AFTERNOON. WINDS WILL DECREASE BACK TO AROUND 10
KTS OR LESS OVERNIGHT WHILE BECOMING MORE SOUTHWESTERLY. SEAS WILL
STAY IN THE 2 FT RANGE THROUGH THE PERIOD.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 230 AM THURSDAY...LIGHT/VARIABLE WINDS EXPECTED WITH A WEAK
PRESSURE GRADIENT ACROSS THE WATERS FRIDAY THROUGH FRIDAY EVENING.
AS RIDGE OF HIGH PRESSURE BUILDS SOUTH INTO THE CAROLINAS EARLY
SATURDAY MORNING THE WIND WILL VEER TO THE NORTHEAST AND INCREASE TO
10 TO 15 KNOTS...POSSIBLY CLOSER TO 15 KNOTS ACROSS THE CAPE FEAR
WATERS FOR A BIT SATURDAY AFTERNOON/EVENING. SEAS WILL INCREASE TO
AROUND 3 FT OR A LITTLE HIGHER AS THE NORTHEAST WINDS INCREASE.
LONG TERM /SUNDAY THROUGH MONDAY/...
AS OF 230 AM THURSDAY...NORTHEAST WINDS WILL BEGIN TO WEAKEN DURING
SUNDAY AS THE RIDGE WEAKENS. COULD SEE ANOTHER PERIOD OF
LIGHT/VARIABLE WINDS DURING MONDAY WITH A WEAK PRESSURE GRADIENT
RETURNING TO THE AREA. SEAS AROUND 3 FT SUNDAY WILL SUBSIDE TO 2-3
FT DURING MONDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SRP
NEAR TERM...REK
SHORT TERM...SRP
LONG TERM...JDW/SRP
AVIATION...DL
MARINE...REK/SRP
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
230 AM EDT THU SEP 3 2015
.SYNOPSIS...
ABOVE NORMAL TEMPERATURES ARE EXPECTED TODAY THROUGH FRIDAY. A WEAK
TROUGH WILL LINGER IN THE AREA THROUGH EARLY FRIDAY. A RIDGE OF HIGH
PRESSURE WILL BUILD IN FROM THE NORTH BEHIND A COLD FRONT THIS
WEEKEND...BRINGING UNSETTLED WEATHER AND COOLER TEMPERATURES THROUGH
THE FIRST PART OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 130 AM THURSDAY...RADAR LOOPS AND OBS SHOW IMPRESSIVE GUST
FRONT DROPPING SOUTH INTO THE FORECAST AREA FROM STORM ACTIVITY TO
THE NORTH. EXPECT NO BIG IMPACTS...JUST A WIND SHIFT TO THE NORTH.
STILL POSSIBLE THAT WE COULD SEE SOME OF THIS CONVECTION TO THE
NORTH DROP INTO OUR NORTHERN TIER OF COUNTIES. PREVIOUS
DISCUSSIONS FOLLOW:
STORMS IN NORTHEASTERN NORTH CAROLINA HAS DEVELOPED A MASSED
OUTFLOW BOUNDARY PUSHING SOUTH THROUGH RALEIGH AND GREENVILLE AT
THIS TIME. A SECOND CLUSTER OF STORMS FROM ASHEBORO TO LEXINGTON
IS MOVING SOUTHEASTWARD. THIS OUTFLOW BOUNDARY IS SURPRISINGLY
DEEP...THE RALEIGH RADAR SHOWS THE BOUNDARY EXTENDING UP TO AROUND
7000 FEET NEAR GREENVILLE WHICH IS DEEP ENOUGH TO LIFT PARCELS AT
THE LFC. ODDS ARE STILL ABOUT 1-IN-4 TO 1-IN-5 CONVECTION WILL
SURVIVE ALL THE WAY DOWN TO LUMBERTON...ELIZABETHTOWN AND BURGAW.
A SMALL (20%) POP IS BEING MAINTAINED HERE AFTER MIDNIGHT.
OTHERWISE MOSTLY CLEAR SKIES WILL CONTINUE OVERNIGHT WITH LOWS
70-75. DISCUSSION FROM 730 PM FOLLOWS...
CLOSELY WATCHING SCATTERED CONVECTIVE SHOWERS AND STORMS ACROSS
THE NORTHWESTERN HALF OF NC SINKING SOUTHEASTWARD. WHILE THE 500
MB COLD POOL CENTERED OVER VIRGINIA SHOULD NOT DIVE THIS FAR
SOUTH...A SURPRISING NUMBER OF MODELS STILL SHOW SHOWERS MAKING IT
INTO SE NORTH CAROLINA STARTING AROUND 3-4 AM. FORECAST SOUNDINGS
SHOW THIS WOULD NOT BE SURFACE- BASED CONVECTION BUT INSTEAD
ROOTED IN A LAYER AROUND 7000 FEET UP. LAPSE RATES BETWEEN 800-400
MB ARE STEEP ENOUGH THAT SHOULD ANYTHING SURVIVE THAT LATE IT
COULD STILL HAVE THUNDER. TO BLEND WITH NWS RAH AND MHX I HAVE
ADDED A 20 POP LATE TONIGHT FROM LUMBERTON TO ELIZABETHTOWN TO
BURGAW...OTHERWISE VERY FEW CHANGES WERE NEEDED TO THE FORECAST
WITH THIS EARLY EVENING UPDATE.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 230 AM THURSDAY...H5 RIDGE AXIS IS SHOWN TO EXTEND FROM THE
SOUTHERN PLAINS AND LOWER MS VALLEY INTO THE MID WEST AND GREAT
LAKES REGION EARLY FRIDAY WITH A WEAK TROUGH ORIENTED NEARLY EAST-
WEST FROM THE MID-ATLANTIC REGION TOWARD THE OHIO VALLEY. THE H5
TROUGH WILL DRIFT SOUTH ACROSS THE SOUTHEASTERN STATES WITH SOME
DURING SATURDAY AS HIGH PRESSURE ALOFT EVOLVES ACROSS NEW ENGLAND.
AT THE SURFACE...A RIDGE WILL BUILD SOUTH ACROSS THE FORECAST AREA
FRIDAY NIGHT INTO SATURDAY BRINGING AN END TO THE ATYPICALLY WARM
TEMPERATURES. THE PRECIPITABLE WATER DOES NOT STAND OUT AS IT IS
EXPECTED TO AVERAGE A LITTLE OVER AN INCH AND A HALF EACH DAY. AN
INCREASE IN LOW-LEVEL CONVERGENCE ON SATURDAY IN NORTHEASTERLY FLOW
TRANSLATES TO SLIGHTLY HIGHER POPS COMPARED TO FRIDAY IN AN
ENVIRONMENT THAT IS UNSETTLED...BUT DEVOID OF A SIGNIFICANT LIFTING
MECHANISM.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 230 AM THURSDAY...WEAK/BROAD AREA OF LOW PRESSURE NOTED IN
500MB PROGS WILL LINGER OVER THE SOUTHEAST UNITED STATES SUNDAY
RESULTING IN A CONTINUATION OF UNSETTLED WEATHER THROUGH TUESDAY AS
IT GRADUALLY WEAKENS OVER THE REGION. THE SURFACE RIDGE WEAKENS
ACROSS THE CAROLINAS AS WELL DURING THE PERIOD WITH LOWER PRESSURE
LINGERING OFF THE COAST. ALTHOUGH THE PRECIPITABLE WATER IS EXPECTED
TO INCREASE TO JUST UNDER TWO INCHES BY MONDAY THE HIGHEST
PRECIPITABLE WATER WILL CONTINUE TO BE SUPPRESSED OFFSHORE TO THE
SOUTHEAST AND SOUTH OF THE AREA. EXPECTING SCATTERED SHOWERS AND A
FEW TSTMS EACH DAY WITH THE BEST CHANCES MONDAY COINCIDENT WITH THE
HIGHEST PRECIPITABLE WATER. MAX TEMPERATURES EACH DAY WILL RANGE
WITHIN A COUPLE DEGREES OF CLIMATOLOGY WHILE THE MINS REMAIN A
COUPLE CATEGORIES ABOVE NORMAL.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 06Z...THE HRRR MODEL HAS BEEN FAIRLY CONSISTENT IN BRINGING
SOME CONVECTION FROM THE NORTHWEST...ASSOCIATED WITH A MODERATE
VORT MAX DROPPING IN FROM VIRGINIA. THE CONVECTION WILL LIKELY
DISSIPATE BY 10-11Z AS IT MOVES OFF THE COAST OF SOUTHEAST NORTH
CAROLINA. THIS IS MAINLY LEANING ON THE NAM MODEL AS THE GFS
SHIFTS THE PRECIP OFFSHORE BEFORE IT GETS HERE. TOOK OUT THE TEMPO
LOWER FOG AT LBT AS THERE WILL LIKELY BE TOO MANY CLOUDS TO
RADIATE EFFECTIVELY. THURSDAY...ANOTHER HOT DAY WITH WEST
NORTHWEST FLOW. SOME SCATTERED CONVECTION MAY DEVELOP AROUND MAX
HEATING...ESPECIALLY ALONG THE RESULTANT.
EXTENDED OUTLOOK...PREDOMINATELY VFR WITH BRIEF MORNING FOG AND
ISOLATED/SCATTERED AFTERNOON SHOWERS AND THUNDERSTORMS.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 130 AM THURSDAY...ABSOLUTELY NO CHANGES WERE NEEDED TO THE
FORECAST WITH THIS LATEST EVENING UPDATE. DISCUSSION FROM 300 PM
FOLLOWS...
A TROUGH WILL BE STRUNG OUT FROM WEST TO EAST SOUTH OF OUR LOCAL
WATERS BUT WEAK HIGH PRESSURE WILL HOLD LOCALLY THROUGH TODAY.
BASICALLY FLOW WILL BE DOMINATED BY THE SEA BREEZE THIS AFTERNOON
WITH ON SHORE GUSTIER WINDS...BASICALLY SE-S. WITH WINDS GENERALLY
10 KT OR LESS...SEAS WILL REMAIN 2 FT OR LESS.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 230 AM THURSDAY...LIGHT/VARIABLE WINDS EXPECTED WITH A WEAK
PRESSURE GRADIENT ACROSS THE WATERS FRIDAY THROUGH FRIDAY EVENING.
AS RIDGE OF HIGH PRESSURE BUILDS SOUTH INTO THE CAROLINAS EARLY
SATURDAY MORNING THE WIND WILL VEER TO THE NORTHEAST AND INCREASE TO
10 TO 15 KNOTS...POSSIBLY CLOSER TO 15 KNOTS ACROSS THE CAPE FEAR
WATERS FOR A BIT SATURDAY AFTERNOON/EVENING. SEAS WILL INCREASE TO
AROUND 3 FT OR A LITTLE HIGHER AS THE NORTHEAST WINDS INCREASE.
LONG TERM /SUNDAY THROUGH MONDAY/...
AS OF 230 AM THURSDAY...NORTHEAST WINDS WILL BEGIN TO WEAKEN DURING
SUNDAY AS THE RIDGE WEAKENS. COULD SEE ANOTHER PERIOD OF
LIGHT/VARIABLE WINDS DURING MONDAY WITH A WEAK PRESSURE GRADIENT
RETURNING TO THE AREA. SEAS AROUND 3 FT SUNDAY WILL SUBSIDE TO 2-3
FT DURING MONDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...REK
SHORT TERM...SRP
LONG TERM...SRP
AVIATION...DL/REK
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
143 AM EDT THU SEP 3 2015
.SYNOPSIS...
ABOVE NORMAL TEMPERATURES ARE EXPECTED THROUGH FRIDAY. A WEAK
TROUGH WILL LINGER IN THE AREA THROUGH EARLY FRIDAY. A RIDGE OF
HIGH PRESSURE WILL BUILD IN FROM THE NORTH BEHIND A COLD FRONT BY
THIS WEEKEND...BRINGING UNSETTLED WEATHER AND COOLER TEMPERATURES
THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 130 AM THURSDAY...RADAR LOOPS AND OBS SHOW IMPRESSIVE GUST
FRONT DROPPING SOUTH INTO THE FORECAST AREA FROM STORM ACTIVITY TO
THE NORTH. EXPECT NO BIG IMPACTS...JUST A WIND SHIFT TO THE NORTH.
STILL POSSIBLE THAT WE COULD SEE SOME OF THIS CONVECTION TO THE
NORTH DROP INTO OUR NORTHERN TIER OF COUNTIES. PREVIOUS
DISCUSSIONS FOLLOW:
STORMS IN NORTHEASTERN NORTH CAROLINA HAS DEVELOPED A MASSED
OUTFLOW BOUNDARY PUSHING SOUTH THROUGH RALEIGH AND GREENVILLE AT
THIS TIME. A SECOND CLUSTER OF STORMS FROM ASHEBORO TO LEXINGTON
IS MOVING SOUTHEASTWARD. THIS OUTFLOW BOUNDARY IS SURPRISINGLY
DEEP...THE RALEIGH RADAR SHOWS THE BOUNDARY EXTENDING UP TO AROUND
7000 FEET NEAR GREENVILLE WHICH IS DEEP ENOUGH TO LIFT PARCELS AT
THE LFC. ODDS ARE STILL ABOUT 1-IN-4 TO 1-IN-5 CONVECTION WILL
SURVIVE ALL THE WAY DOWN TO LUMBERTON...ELIZABETHTOWN AND BURGAW.
A SMALL (20%) POP IS BEING MAINTAINED HERE AFTER MIDNIGHT.
OTHERWISE MOSTLY CLEAR SKIES WILL CONTINUE OVERNIGHT WITH LOWS
70-75. DISCUSSION FROM 730 PM FOLLOWS...
CLOSELY WATCHING SCATTERED CONVECTIVE SHOWERS AND STORMS ACROSS
THE NORTHWESTERN HALF OF NC SINKING SOUTHEASTWARD. WHILE THE 500
MB COLD POOL CENTERED OVER VIRGINIA SHOULD NOT DIVE THIS FAR
SOUTH...A SURPRISING NUMBER OF MODELS STILL SHOW SHOWERS MAKING IT
INTO SE NORTH CAROLINA STARTING AROUND 3-4 AM. FORECAST SOUNDINGS
SHOW THIS WOULD NOT BE SURFACE- BASED CONVECTION BUT INSTEAD
ROOTED IN A LAYER AROUND 7000 FEET UP. LAPSE RATES BETWEEN 800-400
MB ARE STEEP ENOUGH THAT SHOULD ANYTHING SURVIVE THAT LATE IT
COULD STILL HAVE THUNDER. TO BLEND WITH NWS RAH AND MHX I HAVE
ADDED A 20 POP LATE TONIGHT FROM LUMBERTON TO ELIZABETHTOWN TO
BURGAW...OTHERWISE VERY FEW CHANGES WERE NEEDED TO THE FORECAST
WITH THIS EARLY EVENING UPDATE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/...
AS OF 300 PM WEDNESDAY...UPPER RIDGE BUILDS STRONGLY ACROSS MIDDLE
AMERICA AND THIS WILL RESULT IN A TROUGH DIGGING DOWN THE EAST
COAST THU INTO FRI. DEVELOPING NW FLOW ALOFT WILL ALLOW WEAK MID-
LEVEL DISTURBANCES...EMBEDDED IN FLOW...TO IMPACT THE EASTERN
CAROLINAS. THE STRONGEST OF THESE FEATURES DURING THIS TIME FRAME
WILL REACH THE AREA LATER THU AFTERNOON AND THU NIGHT. AT THE
SURFACE...HIGH PRESSURE WILL ASSERT A STRONG ENOUGH PUSH TO BRING
A BACKDOOR COLD FRONT ACROSS THE AREA FRIDAY NIGHT. THE PIEDMONT
TROUGH AND SEABREEZE BOUNDARIES WILL STRENGTHEN THU AFTERNOON AND
THESE MESOSCALE BOUNDARIES SHOULD PROVIDE SOME MODEST LIFT...THUS
ALLOWING SOME CONVECTION TO DEVELOP AS STRONG HEATING INCREASES
THE INSTABILITY.
THE HIGHEST PRECIPITABLE WATER VALUES AND THE GREATEST MOISTURE
DEPTH ARE STILL EXPECTED THU/THU NIGHT...ALTHOUGH NOT THAT
IMPRESSIVE EVEN FOR EARLY SEPTEMBER. AT THIS TIME...WILL KEEP
POPS IN THE SLIGHT CHANCE/CHANCE CATEGORY. HOWEVER...HIGHER POPS
MAY BE WARRANTED AS WE PROGRESS THROUGH LATE WEEK AND ARE BETTER
ABLE TO NAIL DOWN THE TIMING OF THE VARIOUS FEATURES PREVIOUSLY
DISCUSSED.
THE WARMEST DAY WILL BE THU WHEN HIGHS ARE EXPECTED MAINLY IN THE
MID 90S WITH LOWER 90S VERY NEAR THE COAST AND UPPER 80S AT THE
BEACHES. HIGHS ON FRI WILL BE MAINLY IN THE LOWER 90S...STILL ABOVE
NORMAL...UPPER 80S AT THE BEACHES. LOWS WILL BE IN THE LOWER 70S THU
NIGHT AND UPPER 60S TO LOWER 70S FRI NIGHT.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 300 PM WEDNESDAY...COMPLEX MID-LEVEL PATTERN WILL LEAD TO A
CHALLENGING FORECAST WITH LIKELY AN EXTENDED PERIOD OF UNSETTLED
WEATHER ACROSS THE SOUTHEAST. GFS AND ECMWF ARE IN PRETTY GOOD
AGREEMENT THROUGH THE EXTENDED WHICH CREATES HIGHER CONFIDENCE THIS
PERIOD...AND IT APPEARS MUCH OF THE EXTENDED WILL BE UNSETTLED WITH
BELOW NORMAL HIGHS AND SEASONABLE LOWS.
LARGE UPPER RIDGE WILL BUILD ACROSS THE NORTHEAST FROM THE GULF
COAST...DRIVING A SURFACE RIDGE DOWN THE EASTERN SEABOARD. AS THIS
OCCURS...A BACK DOOR TYPE FRONT WILL STALL SOUTH OF THE AREA...AS A
WEAKNESS IN THE PRESSURE FIELD STRENGTHENS AND EXPANDS FROM THE
NE...SOUTH OF THE RIDGE. THIS UPPER TROUGH WILL SHARPEN AND CUT OFF
ACROSS THE SOUTHEAST...AND THEN SIT BASICALLY IN PLACE THROUGH
TUESDAY AS IT IS BLOCKED BY RIDGING ON ALL SIDES. BENEATH THIS
TROUGH...THE REMNANTS OF ERIKA WILL MEANDER NEAR THE SOUTHEAST COAST
MAINTAINING CLOUDS...SHOWERS...AND COOL TEMPERATURES...ESPECIALLY
ALONG THE COAST. STILL SOME UNCERTAINTY INTO HOW MUCH QPF IS
EXPECTED SINCE FORCING IS WEAK...BUT TROPICAL MOISTURE IN THE
VICINITY OF ERIKAS REMNANTS WILL CREATE THE POTENTIAL FOR
SHOWERS...SOME OF WHICH MAY BE HEAVY AT TIMES...ESPECIALLY SUNDAY
THROUGH TUESDAY. WPC QPF SHOWS 1-2 INCHES THROUGH THE
PERIOD...HEAVIEST ALONG THE COAST. GUIDANCE SUGGESTS ERIKAS REMNANTS
WILL FINALLY DISSIPATE ENTIRELY BY WEDNESDAY AND LIFT TO THE NORTH
AS THE BLOCKING RIDGE WEAKENS...THIS WILL LEAD TO IMPROVING AND MORE
SEASONABLE WEATHER AT THE END OF THE EXTENDED.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 06Z...THE HRRR MODEL HAS BEEN FAIRLY CONSISTENT IN BRINGING
SOME CONVECTION FROM THE NORTHWEST...ASSOCIATED WITH A MODERATE
VORT MAX DROPPING IN FROM VIRGINIA. THE CONVECTION WILL LIKELY
DISSIPATE BY 10-11Z AS IT MOVES OFF THE COAST OF SOUTHEAST NORTH
CAROLINA. THIS IS MAINLY LEANING ON THE NAM MODEL AS THE GFS
SHIFTS THE PRECIP OFFSHORE BEFORE IT GETS HERE. TOOK OUT THE TEMPO
LOWER FOG AT LBT AS THERE WILL LIKELY BE TOO MANY CLOUDS TO
RADIATE EFFECTIVELY. THURSDAY...ANOTHER HOT DAY WITH WEST
NORTHWEST FLOW. SOME SCATTERED CONVECTION MAY DEVELOP AROUND MAX
HEATING...ESPECIALLY ALONG THE RESULTANT.
EXTENDED OUTLOOK...PREDOMINATELY VFR WITH BRIEF MORNING FOG AND
ISOLATED/SCATTERED AFTERNOON SHOWERS AND THUNDERSTORMS.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 130 AM THURSDAY...ABSOLUTELY NO CHANGES WERE NEEDED TO THE
FORECAST WITH THIS LATEST EVENING UPDATE. DISCUSSION FROM 300 PM
FOLLOWS...
A TROUGH WILL BE STRUNG OUT FROM WEST TO EAST SOUTH OF OUR LOCAL
WATERS BUT WEAK HIGH PRESSURE WILL HOLD LOCALLY THROUGH TODAY.
BASICALLY FLOW WILL BE DOMINATED BY THE SEA BREEZE THIS AFTERNOON
WITH ON SHORE GUSTIER WINDS...BASICALLY SE-S. WITH WINDS GENERALLY
10 KT OR LESS...SEAS WILL REMAIN 2 FT OR LESS.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 PM WEDNESDAY...THE SLACK PRESSURE GRADIENT...WHICH HAS
BEEN IN PLACE FOR SEVERAL DAYS...WILL FINALLY BEGIN TO TIGHTEN...
AND WITH THAT WE WILL SEE WIND SPEEDS INCREASING. THE HIGHEST
WINDS THIS PERIOD ARE EXPECTED IN THE WAKE OF A BACKDOOR COLD
FRONT FRI NIGHT. WIND SPEEDS FRI NIGHT ARE EXPECTED TO BE UP TO 15
TO 20 KT AS A NE SURGE EXPANDS SOUTHWARD ACROSS THE WATERS AS HIGH
PRESSURE BUILDS FROM THE N.
A LAND BREEZE WILL ALLOW FOR A LIGHT OFFSHORE WIND THU MORNING. THE
SEABREEZE AND PIEDMONT TROUGH WILL INCREASE SW WINDS TO AROUND 10 KT
THU AFTERNOON AND EVE. SEAS WILL BE 2 FT OR LESS WITH 3 FT SEAS
EXPANDING SOUTHWARD ACROSS THE WATERS FRI NIGHT.
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 300 PM WEDNESDAY...HIGH PRESSURE WILL RIDGE DOWN THE COAST
STRONGLY SAT/SUN BEFORE SLOWLY WEAKENING EARLY NEXT WEEK. AS THIS
HIGH BUILDS SW FROM NEW ENGLAND...IT WILL BE ACCOMPANIED BY A NE
SURGE...DRIVING WINDS UP TO AROUND 15 KT SATURDAY AND SUNDAY.
WINDS WILL VEER SLOWLY ON MONDAY TO BECOME MORE EASTERLY AS THE
RIDGE WEAKENS...WITH SPEEDS DROPPING TO AROUND 10 KT AT THE END OF
THE PERIOD. THE SEA SPECTRUM WILL BE SIGNIFICANTLY DOMINATED BY A
NE WIND WAVE THROUGH THE PERIOD...WHICH WILL MASK A LOW-AMPLITUDE
SE SWELL. WAVE HEIGHTS WILL BE 2-3 FT EARLY SATURDAY...RISING TO
3-4 FT LATE SATURDAY AND SUNDAY AS THE NE FETCH PERSISTS. WAVE
HEIGHTS WILL THEN EASE A BIT MONDAY ON THE SLACKENING WINDS.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...RJD
NEAR TERM...REK/TRA/RGZ
SHORT TERM...RJD
LONG TERM...JDW
AVIATION...DL
MARINE...REK/RJD/TRA/JDW/RGZ/SRP
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1242 AM CDT THU SEP 3 2015
.UPDATE...
ISSUED AT 1242 AM CDT THU SEP 3 2015
MAIN CONCERN THIS UPDATE IS FOG POSSIBILITY...ESPECIALLY ACROSS
CENTRAL NORTH DAKOTA. DEWPOINT TEMPERATURES IN THE 60S TO LOWER 70S
WITH HUMID SOUTHEAST FLOW. RELATIVE HUMIDITY VALUES ALREADY REACHING
100 PERCENT SOME LOCALES. WENT WITH PATCHY FOG CENTRAL. ONLY
LIMITING FACTOR FOR MORE WIDESPREAD FOG WOULD BE THE SOUTHEAST WINDS
OF 5 TO 10 MPH THAT MAY BE ENOUGH TO KEEP SUFFICIENT MIXING TO LIMIT
WIDESPREAD NATURE OF FOG. OTHERWISE ADJUSTED CURRENT HOURLY
TEMPERATURE TRENDS. CURRENT FORECAST ON TRACK.
UPDATE ISSUED AT 943 PM CDT WED SEP 2 2015
NO CHANGES TO THE GOING FORECAST.
UPDATE ISSUED AT 754 PM CDT WED SEP 2 2015
MONTANA SHOWERS DISSIPATED AS THEY NEARED THE NORTH DAKOTA BORDER.
UPDATED TO DRY OUT THE FORECAST.
UPDATE ISSUED AT 441 PM CDT WED SEP 2 2015
WILL NEED TO DO A FORECAST UPDATE TO ACCOUNT FOR SHOWERS MOVING
FROM THE MILES CITY TO GLENDIVE AREA OF MONTANA TOWARD THE NORTH
DAKOTA BORDER. THE HRRR IS HANDLING THE PRECIPITATION THE BEST AS
COMPARED TO OTHER HI RES SHORT TERM MODELS. THE HRRR HAS THE
SHOWERS DEPICTED...AND BRINGS THEM INTO NORTH DAKOTA...EVEN INTO
THE CENTRAL PART OF THE STATE LATER.
KMLS ASOS HAD A WIND GUST OF 52 KNOTS...60 MPH...HOWEVER...THE
STATION REPORTED NO THUNDER AND THE LIGHTNING NETWORK SHOWED NO
LIGHTNING. SO...IT WAS A SHOWER THAT MIXED DOWN HIGHER WIND AND
LIKELY EVAPORATION ADDED TO THE DOWNWARD TRANSPORT. DOWNDRAFT CAPE
IS ANALYZED 1700-1800 UNITS ACROSS WESTERN NORTH DAKOTA.
WILL ADD POPS TO THE WEST AND MAY NEED TO BRING THEM INTO THE
CENTRAL PART OF THE STATE ON A LATER UPDATE. WILL THE ACTIVITY
HOLD TOGETHER AS DEPICTED BY THE HRRR...IS THE QUESTION.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 330 PM CDT WED SEP 2 2015
MAIN CONCERNS THIS PERIOD WILL BE SOME PATCHY FOG TONIGHT...
AND TEMPERATURES AND SOME SLIGHT CHANCES FOR THUNDERSTORMS ALONG
A SLOWLY MOVING FRONTAL BOUNDARY ACROSS THE NORTHWEST ON THURSDAY.
TONIGHT...THE H500 FLOW REMAINS ORIENTED SOUTHWEST TO NORTHEAST.
EXPECT THE COLD FRONTAL BOUNDARY WHICH IS ALIGNED WITH THE FLOW
ALOFT TO ONLY MOVE SLOWLY EAST TONIGHT AND THURSDAY. THIS WILL
GIVE THE REGION ANOTHER OPPORTUNITY FOR VERY WARM TEMPERATURES
THURSDAY ALONG AND AHEAD OF THE FRONT. HIGHS CENTRAL SECTIONS WILL
BE CLOSE TO 100. RELATIVELY COOLER AIR...ALTHOUGH STILL IN THE
MID 80S...WILL MOVE INTO THE NORTHWEST. LOW LEVEL MOISTURE
POOLING ALONG THE JAMES RIVER VALLEY TONIGHT WILL FAVOR MUGGY
CONDITIONS AND SOME PATCHY FOG TONIGHT WITH DEWPOINTS AROUND 70.
ON THURSDAY THE HEAT INDEX VALUES WILL RISE TO NEAR 100 ACROSS THE
JAMES RIVER VALLEY BY AFTERNOON.
THE NAM/GFS BOTH DEVELOP SOME WEAK CONVECTION ALONG THE FRONTAL
BOUNDARY THURSDAY. THE WRF MODEL DOES TOO BUT IN THE AFTERNOON.
WILL ADD ISOLATED THUNDERSTORMS FAR WEST INTO THE NORTH CENTRAL
THURSDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 330 PM CDT WED SEP 2 2015
A SIGNIFICANT PATTERN CHANGE WILL IMPACT THE NORTHERN PLAINS FOR
THE UPCOMING HOLIDAY WEEKEND...WITH COOLER AND WETTER CONDITIONS.
STRONG UPPER LEVEL LOW DROPPING INTO THE PACIFIC NORTHWEST TODAY
WILL BECOME AN OPEN WAVE AND DEEPEN OVER THE WEST COAST THROUGH
SATURDAY. BY THURSDAY NIGHT EMBEDDED S/WV IMPULSES WILL BEGIN TO
APPROACH THE REGION...AND WHEN COUPLED WITH A SLOW MOVING SFC
BOUNDARY WILL RESULT IN CHANCES FOR SHOWERS/THUNDERSTORMS WEST TO
EAST DURING THE NIGHT. A PARTICULARLY STRONG EMBEDDED WAVE WILL
LIFT NORTHEAST ACROSS THE DAKOTAS LATE THURSDAY NIGHT/FRIDAY
MORNING AND MAY BRING MODERATE TO HEAVY RAIN TO PORTIONS OF NORTH
CENTRAL AND EASTERN NORTH DAKOTA DURING THAT TIMEFRAME.
FRIDAY-SATURDAY THE WEST COAST UPPER TROUGH BEGINS TO MOVE FARTHER
INLAND AND WILL DIRECT A SERIES OF SHORTWAVE ENERGY IMPULSES ACROSS
THE NORTHERN PLAINS. THE EXPECTED INCREASE IN CLOUD COVER AND CAA
IN THE WAKE OF THE SFC FRONT WILL RESULT IN MUCH COOLER
TEMPERATURES...WITH HIGHS DROPPING INTO THE 70S MOST AREAS BY
SATURDAY. SATURDAY NIGHT INTO SUNDAY THE BASE OF THE UPPER TROUGH
LIFTS NORTHEASTWARD ACROSS THE ROCKIES AND INTO THE NORTHERN
PLAINS...REACHING FAR SOUTH CENTRAL CANADA SUNDAY NIGHT. THIS
TIME PERIOD (FRIDAY-SUNDAY) WILL SEE VERY GOOD CHANCES FOR SHOWERS
AND THUNDERSTORMS. HEAVIEST PRECIPITATION FORECAST ACROSS THE
NORTH. TOTAL RAINFALL THURSDAY NIGHT THROUGH SUNDAY IS FORECAST TO
RANGE FROM AROUND HALF AN INCH SOUTHWEST...TO NEAR 2 INCHES NORTH.
HEAVIER AMOUNTS VERY POSSIBLE WITH THUNDERSTORMS. INSTABILITY NOT
OVERLY IMPRESSIVE SO WHILE A FEW STRONGER STORMS MAY FORM...THE
OVERALL SEVERE THREAT WILL BE MINIMAL.
MUCH COOLER IN THE WAKE OF THE STORM SYSTEM MONDAY...WITH FORECAST
HIGHS MID 60S TO LOW 70S. A QUASI-ACTIVE UPPER LEVEL ZONAL FLOW
SETS UP EARLY TO MID NEXT. THIS IS A DEVIATION FROM PREVIOUS
MODELS SO UNCERTAINTY RATHER HIGH AT THIS POINT. STILL LOOKS LIKE
A SLOW MODERATION IN TEMPERATURES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1242 AM CDT THU SEP 3 2015
LOW PRESSURE IN EASTERN MONTANA IS FORECAST TO MOVE EASTWARD TO THE
ND/MT BORDER BY DAYBREAK...AND INTO CENTRAL NORTH DAKOTA BY AROUND
00Z. SOUTHEAST WINDS EARLY THIS MORNING WILL CONTINUE TO BRING HUMID
AIR INTO THE REGION...WITH PATCHY FOG POSSIBLE TOWARD DAYBREAK.
ADDED TEMPO 3SM BR BETWEEN 10Z-14Z FOR NOW AT KMOT/KBIS/KJMS.
OTHERWISE VFR CONDITIONS AFTER 14Z EXPECTED. ISOLATED THUNDERSTORMS
POSSIBLE THIS AFTERNOON NORTHWESTERN ND BUT CHANCES TOO SMALL TO
MENTION IN TAFS. SCATTERED TSTMS POSSIBLE AFT 00Z AT
KISN/KDIK/KMOT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JV
SHORT TERM...WAA
LONG TERM...NH
AVIATION...JV
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
419 AM CDT THU SEP 3 2015
.SHORT TERM /TODAY THROUGH FRIDAY/...THE LATEST WV IMAGERY SHOWS A
CIRCULATION JUST TO THE EAST OF BRO THIS MORNING. THIS VERIFIES THE
MODEL FORECAST OF THIS FEATURE`S SOUTHWARD MOVEMENT FROM YESTERDAY.
DRIER AIR IS TO THE WEST OF THE CIRCULATION...PRETTY MUCH COVERING
THE CWA. RADAR SHOWS ISOLATED CONVECTION OVER THE GULF TO THE EAST
THROUGH SOUTH OF BRO HOWEVER.
THE MARINE CONVECTION SHOULD NOT POSE MUCH OF A PROBLEM FOR THE CWA.
ON THE OTHER HAND...FORECAST PWAT WILL REMAIN NEAR TWO INCHES TODAY
AND FRIDAY...WITH THE HRRR SHOWING THE DEVELOPMENT OF A SEA BREEZE
FROM LATE MORNING TO MID AFTERNOON. MOSTLY CLEAR SKIES THIS MORNING
WILL GIVE EARLY ON DAYTIME HEATING A CHANCE TO CONTRIBUTE TO THE
ACTION...WITH OUTFLOW BOUNDARIES FROM COLLAPSING CELLS INTERSECTING
WITH EACH OTHER AND WITH THE SEA BREEZE. EFFICIENT TROPICAL...SUMMER
TIME RAIN MAKING CELLS MAY RESULT IN BRIEFLY HEAVIER DOWNPOURS...
WITH NUISANCE FLOODING POSSIBLE IN SOME AREAS.
THE UPPER CIRCULATION MAY BE ABLE TO REMAIN IDENTIFIABLE FOR ANOTHER
24 HRS AS IT DRIFTS FARTHER SOUTH AND WEST...BUT IT WILL EVENTUALLY
BE OVERSHADOWED BY RIDGING BUILDING OVER TEXAS. HOWEVER...THIS WILL
NOT TOTALLY SUPPRESS ANOTHER DAY OF UNORGANIZED CONVECTION AROUND
THE AREA FRIDAY...SOME OF WHICH WILL FEED OFF THE SEA BREEZE.
HAD NO REAL ISSUES CONTINUING WITH A MODEL CONSENSUS TO BUILD THE
SHORT TERM FORECAST. HIGH TEMPERATURES OUT WEST ARE DRIFTING UP A
BIT...TOPPING OUT NEAR THE CENTURY MARK FRIDAY AFTERNOON. POPS ARE
STILL PAINTED SLIGHTLY HIGHER OVER THE GULF THAN OVER LAND AREAS.
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...500 MB RIDGING WILL
REBUILD OVER TX AND NORTHERN MEXICO THIS WEEKEND INTO NEXT WEEK.
THIS WILL ALLOW A DRIER AND MORE SUBSIDENT ATMS TO BUILD OVER THE
AREA. THE BETTER MOISTURE VALUES WILL REMAIN CONFINED MAINLY TO
THE OFFSHORE WATERS AND NEAR THE COASTLINE AS A 500 MB CLOSED LOW
DEVELOPS OVER THE EASTERN AND CENTRAL GULF OF MEX. OVERALL THIS
TREND WILL TEND TO LIMIT THE CONV POTENTIAL THROUGHOUT THE
EXTENDED RANGE PERIOD. HOWEVER ISOLD MAINLY SEA BREEZE/DIURNALLY
DRIVEN CONV WILL REMAIN A THREAT THROUGH NEXT WED DUE TO THE
BETTER TROPICAL MOISTURE VALUES REMAINING POSITIONED JUST
OFFSHORE.
1000-500 MB THICKNESS VALUES WILL START TO INCREASE STEADLY
THROUGH DAY 7 ALLOWING THE HIGH TEMPS TO WARM SOMEWHAT. HOWEVER
RECENT RAINFALL OVER THE REGION WILL TEND TO LIMIT THE WARMUP DUE
TO THE HIGHER SOIL MOISTURE VALUES.
THE ECMWF AND GFS MEX MOS GUIDANCE ARE IN PRETTY GOOD AGREEMENT
FOR BOTH POPS AND TEMPS THROUGH DAY 7. 500 MB HEIGHTS FIELDS
COMPARISONS BETWEEN THE GFS AND THE ECMWF THROUGH NEXT FRIDAY
INDICATE PRETTY GOOD AGREEMENT IN THE PLACEMENT OF THE 500 MB
RIDGE AXIS OVER TX AND MEXICO AND THE BROAD TROFFING OVER THE GULF
OF MEX. RUN TO RUN CONSISTENCY WITH THE GFS MEX MOS TEMPS AND POPS
ARE PRETTY STABLE. SO OVERALL CONFIDENCE IN THE LONGER RANGE MODEL
GUIDANCE IS ABOVE AVERAGE AT THIS TIME. WILL GO WITH A GENERAL
50/50 MODEL BLEND FOR BOTH TEMPS AND POPS IN THE LONGER TERM
PERIOD.
&&
.MARINE...TODAY THROUGH FRIDAY...LITTLE CHANGE IN THE SHORT TERM AS
HIGH PRESSURE REMAINS IN PLACE OVER THE NORTHWEST GULF...WITH
SLIGHTLY LOWER PRESSURE TO THE SOUTH AND INLAND. THE RESULT WILL
BE LIGHT TO MODERATE SOUTH SOUTHEAST WINDS AND LOW TO MODERATE
SEAS. THERE WILL BE LITTLE RELIEF FROM ISOLATED TO SCATTERED
SHOWERS AND TSTMS IN THE SHORT TERM HOWEVER...WITH A MID LEVEL LOW
APPROXIMATELY OVERHEAD.
FRIDAY NIGHT THROUGH SUNDAY...BROAD SURFACE RIDGING OVER THE GULF
OF MEX AND THE TX COASTLINE WILL MAINTAIN LIGHT TO MODERATE S-SE
SURFACE WINDS FOR BOTH THE BAY AND GULF WATERS. THE GULF SWELLS
WILL REMAIN FAIRLY LOW DUE TO THE WEAKER SURFACE FLOW. NO SCA
CONDITIONS EXPECTED THROUGH SUNDAY. THE LATEST TROPICAL WEATHER
OUTLOOK FROM NHC DISCUSSES TS FRED IN THE ATLANTIC AND A TROPICAL
WAVE MOVING OFF OF THE WEST COAST OF AFRICA. THE GULF OF MEX
AND THE CARIB SEA REMAIN CLEAR OF TROPICAL ACTIVITY AT THIS TIME.
&&
.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL 90 79 91 80 / 30 20 20 20
BROWNSVILLE 90 78 91 77 / 40 20 20 10
HARLINGEN 92 77 94 77 / 40 20 20 10
MCALLEN 94 79 96 80 / 30 10 20 10
RIO GRANDE CITY 97 77 98 77 / 20 20 10 10
SOUTH PADRE ISLAND 86 80 86 81 / 30 30 30 20
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
SHORT TERM...55
LONG TERM...60
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1153 PM CDT WED SEP 2 2015
.DISCUSSION...
06Z TAF DISCUSSION IN AVIATION SECTION.
&&
.AVIATION...
WINDS HAVE DECOUPLED AND HAVE ALLOWED T/TD SPREADS TO NARROW AT
THE SURFACE. WITH A SCT/BKN HIGH CLOUDS SOME MVFR CIGS HAVE
DEVELOPED IN A FEW SPOTS INCLUDING KIAH/KHOU. THINK LOW STRATOCU
WILL LIKELY BE SCT/BKN THROUGH THE MORNING BUT WILL CARRY MVFR
CIGS IN THE TAFS. ALSO ADDED MENTION OF IFR CIGS FOR KCLL AND
MENTIONED MORE PESSIMISTIC CONDITIONS AT KCLL/KUTS/KCXO MAINLY FOR
FOG BUT COULD SEE AN IFR CIG AS WELL.
SHORT RANGE HRRR STILL SHOWING CONVECTION COMING INLAND AROUND
10-12Z PERHAPS SOONER. ANY SHRA SHOULD WEAKEN LATE MORNING ALONG
THE COAST BUT THEN POSSILBY REDEVELOP WITH DAY TIME HEATING
FARTHER INLAND. NOT SEEING AS MUCH DEEP MOISTURE IN MODEL GUIDANCE
AND UPPER LOW MAY BE WEAKENING...SO THINK ACTIVITY WILL BE MORE
ISO IN NATURE. SHOWER ACTIVITY SHOULD END IN THE EVENING WITH LOSS
OF DAY TIME HEATING AGAIN.
39
&&
.PREV DISCUSSION... /ISSUED /
DISCUSSION...
SHOWERS ENDED WITH SUNSET ACROSS THE CWA AND WILL LEAVE A FEW
HOURS OF TRANQUIL WEATHER. EXPECT TO SEE AN INCREASE DURING THE
EARLY MORNING HOURS ONCE AGAIN OVER THE WARM WATER AND NEAR THE
COAST...SPREADING OVER MORE OF THE COASTAL REGIONS THROUGH
SUNRISE. OTHERWISE...NO CHANGES NEEDED OVERNIGHT.
PREV DISCUSSION... /ISSUED /
DISCUSSION...
00Z TAF DISCUSSION IN AVIATION SECTION.
AVIATION...
WATER VAPOR IMAGERY SHOWS UPPER LOW OFF THE LOWER TX COAST WITH A
SHEAR AXIS EXTENDING ACROSS THE AREA FROM THE LOW. SHOWER ACTIVITY
SHOULD BE COMING TO AN END THE NEXT COUPLE OF HOURS BUT UNTIL THEN
WILL HAVE MINOR IMPACTS AT KIAH. EXPECT VFR CIGS FOR MOST AREAS.
KCLL/KUTS/KCXO MAY SEE SOME REDUCED VSBY AND LOW CIGS FOR THE
MORNING HOURS. NAM/GFS/LAMP GUIDANCE ALL GO WITH IFR/LIFR
CATEGORIES FOR THE MORNING. DO NOT THINK IT WILL BE THAT
PESSIMISTIC SO WILL MENTION MVFR CIGS IN A TEMPO GROUP FOR NOW.
EXPECT MORE OF THE SAME WITH SHOWERS DEVELOPING EARLY MORNING
ALONG THE COAST. SHRA MAY DEVELOP INLAND LIKE TODAY WITH MAYBE AN
ISO TSRA BUT LOW CONFIDENCE AT THIS POINT.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 73 92 75 94 76 / 20 20 10 20 10
HOUSTON (IAH) 73 91 75 93 76 / 30 30 20 30 10
GALVESTON (GLS) 77 88 79 90 79 / 50 50 30 40 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...48
AVIATION/MARINE...39
AREA FORECAST DISCUSSION...UPDATED
NWS CHEYENNE WY
334 AM MDT THU SEP 3 2015
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 300 AM MDT THU SEP 3 2015
PRETTY QUIET WEATHER EARLY THIS MORNING ACROSS THE FORECAST AREA.
CURRENT WATER VAPOR LOOP SHOWS A RIDGE AXIS BUILDING OVER THE
GREAT PLAINS AS A BROAD UPPER LEVEL TROUGH SETTLES OVER THE
PACIFIC NORTHWEST...BRINGING MUCH NEEDED RAINFALL TO WASHINGTON
AND OREGON. THIS SYSTEM WILL EVENTUALLY IMPACT WYOMING THIS
WEEKEND. BEFORE THIS...CURRENT WATER VAPOR ALSO SHOWS A WELL
DEFINED SHORTWAVE DISTURBANCE ALOFT NEAR THE FOUR CORNERS REGION
WITH MID TO HIGH CLOUDS MOVING NORTHWARD WELL AHEAD OF IT. THIS
FEATURE WILL BE THE MAIN FORECAST CONCERN TODAY. A FEW MODELS
SHOW THIS FEATURE MOVING OVER SOUTHEAST WYOMING THIS AFTERNOON
PRODUCING SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS.
THUNDERSTORMS MAY PRODUCE SOME HEAVY RAINFALL AS SHORT RANGE
MODELS SUCH AS THE HRRR INDICATE REDEVELOPMENT AND TRAINING OVER
THE SAME AREA INTO LATE THIS EVENING. THIS IS DUE TO A POTENT
UPPER LEVEL JET AND GOOD 300MB DIFLUENCE ALOFT. HOWEVER...NOT ALL
MODELS AGREE ON THE TIMING OF THIS FEATURE...WITH THE ECMWF AND
GEM 3 TO 6 HOURS BEHIND THE GFS. DUE TO PEAK HEATING AND AVAILABLE
INSTABILITY...THIS TIMING DIFFERENCE IS SIGNIFICANT. THE NEW 06Z
NAM IS IN GOOD AGREEMENT WITH THE GFS AND HRRR...SO CONFIDENCE IS
INCREASING THAT SEVERAL BANDS OF SHOWERS AND TSTORMS WILL DEVELOP
OVER THE ROCKY MOUNTAINS AND QUICKLY LIFT NORTHEAST ACROSS THE I25
AND I80 CORRIDORS BY THIS AFTERNOON. INCREASED POP ACROSS MOST OF
THE AREA WITH THE EXCEPTION OF CARBON COUNTY. INCREASED POP
BETWEEN 30 TO 60 PERCENT FURTHER SOUTH AND WEST...SINCE THERE IS
STILL LOW CONFIDENCE IN SHOWER/TSTORM COVERAGE NORTH OF THE PLATTE
RIVER VALLEY DUE TO TIMING DIFFERENCES.
FRIDAY WILL BE PRETTY SIMILAR TO THURSDAY WITH HIGH TEMPERATURES
IN THE 80S TO MID 90S AND ANOTHER GOOD CHANCE OF AFTERNOON SHOWERS
AND TSTORMS. IN FACT...CONDITIONS APPEAR MORE FAVORABLE IN THE
EVENING AS THE NAM...GFS...AND ECMWF SHOW QUITE A BIT OF UPPER
LEVEL DIFLUENCE DUE TO JET DYNAMICS ALOFT. THIS DYNAMIC LIFT PEAKS
BETWEEN 00Z TO 06Z FRIDAY EVENING BEFORE LIFTING NORTHEAST.
INCREASED POP UP TO 45 PERCENT ACROSS THE HIGH PLAINS FRIDAY
EVENING.
THE UPPER LEVEL TROUGH OVER THE PACIFIC NORTHWEST WILL MOVE
TOWARDS THE FORECAST AREA ON SATURDAY. IT WILL BE SLIGHTLY COOLER
WITH HIGHS IN THE UPPER 80S TO UPPER 80S...BUT THE PRIMARY COLD
FRONT WILL NOT ENTER SOUTHEAST WYOMING UNTIL LATE SATURDAY NIGHT.
THIS MAIN STORM SYSTEM IS EXPECTED TO MOVE NORTHEAST AND REMAIN
NORTH OF THE FORECAST AREA. KEPT POP BETWEEN 10 TO 20 PERCENT
WITH THE HIGHEST CHANCE ACROSS THE MOUNTAINS...DUE TO SOME DRIER
AIR ALOFT AND A STABLE LAYER AROUND 500MB WHICH WILL INHIBIT
WIDESPREAD CONVECTION.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 230 AM MDT THU SEP 3 2015
THE UPPER LEVEL TROUGH WILL SWING NORTHEASTWARD ACROSS NORTHERN WY
ON SAT NIGHT AND SUN MORNING WITH AN ASSOCIATED FROPA. WINDS WILL
REALLY INCREASE BEHIND THE FRONT ON SUN MORNING AS THE MODELS SHOW
700MB WINDS OF 35-40 KTS OVER SOUTHEAST WY. THE GRADIENT DOES BEGIN
TO RELAX BY THE AFTN SO WINDS WILL COME DOWN SOME. WITH A VERY DRY
AIRMASS IN PLACE ON SUN AND MIN RH VALUES FALLING TO AROUND 15
PERCENT...THERE WILL LIKELY BE SOME FIRE WEATHER CONCERNS DESPITE
THE COOLER TEMPS. DRY WESTERLY MIDLVL FLOW WILL REMAIN IN PLACE
THROUGH EARLY NEXT WEEK WITH PW VALUES OF ONLY 0.25-0.5 INCHES AND
NO HINT OF ANY MONSOONAL MOISTURE INTRUSION. TEMPS WILL BE AROUND
NORMAL FOR EARLY SEP WITH COOLER NIGHTS THAN WE HAVE SEEN RECENTLY.
THE MODEL DIFFERENCES BETWEEN THE GFS AND ECMWF REALLY BEGIN TO SHOW
UP BY TUES AS THE GFS SHOWS A STRONGER SHORTWAVE MOVING ACROSS WY.
REGARDLESS OF THE SOLN...A DRY FCST WILL PREVAIL WITH LIMITED
MOISTURE AND DYNAMICS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1157 PM MDT WED SEP 2 2015
VFR CONDITIONS THROUGH THE TAF PERIOD. WINDS WILL REMAIN LIGHT
THROUGH THURSDAY MORNING. ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS WILL DEVELOP AFTER 20Z THURS ACROSS MUCH OF THE
REGION. GUSTY AND ERRATIC WINDS ALONG WITH BRIEF HEAVY RAIN WILL
BE POSSIBLE WITH THE STORMS.
&&
.FIRE WEATHER...
ISSUED AT 230 AM MDT THU SEP 3 2015
IT WILL BE PRETTY DRY INITIALLY THIS AFTERNOON OVER EAST CENTRAL
WYOMING BEFORE SOME SUBTROPICAL MOISTURE MOVES INTO THE
AREA...AHEAD OF AN UPPER LEVEL DISTURBANCE. ALTHOUGH FIRE WEATHER
CONCERNS ARE LOW TODAY...WILL HAVE TO MONITOR WIND SPEEDS ACROSS
ZONE 301 AND 302. FOR NOW...WINDS ARE EXPECTED TO BE BELOW 20 MPH
AT THIS TIME. MINIMAL FIRE WEATHER CONCERNS ARE ANTICIPATED FRIDAY
AND SATURDAY AS THUNDERSTORM COVERAGE WILL INCREASE AND RELATIVE
HUMIDITIES WILL TREND HIGHER...MINIMUM DAYTIME RELATIVE HUMIDITIES
WILL BE BETWEEN 20 TO 30 PERCENT BY SATURDAY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...TJT
LONG TERM...ZF
AVIATION...ZF
FIRE WEATHER...TJT
AREA FORECAST DISCUSSION
NWS ALBANY NY
654 AM EDT THU SEP 3 2015
.SYNOPSIS...
A WEAK COLD FRONT WILL TRACK ACROSS THE REGION TODAY. THIS WILL BE
THE MAIN FOCUS MECHANISM FOR ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS TODAY...WITH THE BEST PROBABILITIES ACROSS THE
TERRAIN. THEREAFTER...HIGH PRESSURE BUILDS ACROSS THE REGION FOR
THE HOLIDAY WEEKEND WITH MAINLY DRY CONDITIONS AND ABOVE
SEASONABLE TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 645 AM EDT...SATELLITE IMAGERY CONTINUES TO SHOW SCT-BKN
CI/CS WITH SOME PATCHY FOG PER METARS AND EARLY MORNING SUNRISE
WEB CAMS. 06Z GUIDANCE REMAINS SOMEWHAT CONSISTENT WITH THE
PASSAGE OF THE FRONTAL BOUNDARY/S/ YET COVERAGE REMAINS IN
QUESTION. HRRR REMAINS LESS THAN IDEAL YET THE MAV MOS POPS CAME
IN HIGHER. FOR NOW...NO CHANGES TO THE CURRENT FORECAST WITH THE
HIGHER VALUES ACROSS THE TERRAIN. OTHERWISE...MINOR TWEAKS PER
OBSERVATIONS AND SATELLITE ANALYSIS.
PREV DISC...PER THE SURFACE ANALYSIS A WEAK PRE FRONTAL TROUGH
AXIS WAS DRAPED ALONG THE ST LAWRENCE RIVER VALLEY WITH A SLIGHTLY
STRONGER FRONT /COLD FRONT/ ADVANCING SOUTHWARD ACROSS LOWER
ONTARIO/QUEBEC. TRENDS IN THE IR SATELLITE IMAGERY CONTINUE ALONG
THE PREVIOUS ESTF WITH WARMING CLOUD TOPS WHICH COINCIDES WITH THE
WEAKENING SHOWER TREND ACROSS THE NORTHERN DACKS AND CHAMPLAIN
VALLEY. OTHERWISE...A THIN SCT-BKN CI/CS CANOPY WAS ACROSS MOST OF
THE REGION AND WHERE ENOUGH BREAKS HAVE OCCURRED THIS HAS ALLOWED
FOR FOG FORMATION TO COMMENCE PER A FEW METARS AND REGIONAL WEB
CAMS. AS SUNRISE APPROACHES...EXPECT THE FOG TO LIFT AND DISSIPATE
AS THE CANOPY OF HIGH CLOUDS CONTINUES TO THICKEN. LATER THIS
MORNING AND INTO THE AFTERNOON...THE COMBINATION OF RELATIVELY
HIGH LOW LEVEL MOISTURE AND THE APPROACH OF THE WEAK COLD FRONT
WILL ALLOW FOR LOW LEVEL CONVERGENCE TO INCREASE AND FOR SOME
CONVECTION TO DEVELOP. LATEST NCEP MODEL SUITE OFFER QUITE A
DIFFERENT APPROACH TO THE AMOUNT OF INSTABILITY ACROSS THE REGION
WITH THE NAM REMAINING THE HIGHEST WITH SBCAPES CLIMBING IN EXCESS
OF 2K J/KG. THE GFS IS ABOUT HALF AS MUCH WHICH IS IN CLOSER
AGREEMENT WITH THE HOURLY MESOSCALE UPDATES FROM THE RAP13/HRRR.
THIS IS LIKELY THE CULPRIT OF THE FORECAST SFC DEWPOINTS AS
UPSTREAM VALUES WERE CURRENTLY IN THE MID 60S AS OPPOSED TO THE
NAM WITH VALUES CLOSE TO 70F. AS FOR LAPSE RATES...MODEST VALUES
SEEN IN THE BUFR PROFILES WITH AN AVERAGE 6.5-7.0 C/KM WITHIN THE
H850-500 LAYER. YET THE WIND SHEAR IS LESS THAN IDEAL FOR
ORGANIZED CONVECTION WITH VALUES 20KTS OR LESS. PER SPC
COORDINATION...GENERAL THUNDERSTORM THREAT AND PER THOSE
SOUNDINGS...COULD NOT RULE OUT 1-2 EVENTS ACROSS THE REGION AS THE
COMBINATION OF INVERTED-V TYPE SOUNDINGS AND PRECIP LOADING
CONVECTION COULD RESULT IN AN ISOLATED DOWNBURST.
TEMPERATURES REMAIN ABOVE NORMAL ONCE AGAIN BUT SLIGHTLY COOLER
THAN WEDNESDAYS HIGHS DUE TO THE AFOREMENTIONED CLOUD COVERAGE
AND THE CHANCE FOR PRECIP WITH MAINLY MID 80S FOR VALLEY LOCATIONS
AND 70S FOR THE TERRAIN.
TONIGHT RESIDUAL CONVECTION SHOULD DISSIPATE AS SURFACE
ANTICYCLONE BUILDS IN FROM NORTHEAST CANADA. TRENDS IN THE MODEL
SUITE SUGGEST LOW LEVEL MOISTURE FROM THE ENE TRAJECTORIES ALONG
WITH UPSLOPE CONDITIONS INTO THE GREENS...BERKS AND NW CT AND SLOW
MOVEMENT OF THE FRONTAL MOVEMENT SOUTH OF I90 COULD KEEP CLOUDS A
BIT LONGER AND PERHAPS AN ISOLATED SHOWER. MOS VALUES OVERNIGHT
ARE VERY CLOSE AND A BLENDED APPROACH WAS UTILIZED. FOG POTENTIAL
IS NOT THAT CLEAR AT THIS TIME AS WE WATCH THE POTENTIAL FOR
STRATUS DEVELOPMENT.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
FRIDAY...STILL SOME QUESTION JUST HOW MUCH LOW LEVEL STRATUS WILL
BE ACROSS THE REGION AS THE GFS IS MORE AGGRESSIVE THAN THE NAM.
HOWEVER...THEY BOTH AGREE THE WEAKENING FRONTAL BOUNDARY MAY GET
HUNG UP ALONG THE I84 CORRIDOR WHERE WE WILL KEEP THE SLIGHT
CHANCE POPS AT THIS TIME ALONG WITH ADDITIONAL CLOUD COVERAGE.
OTHERWISE...BREAKS IN THE CLOUD COVERAGE AND AS H925-850 COOL OFF
FROM THE ENE INTO THE LOWER TEENS...THIS SHOULD YIELD EVEN COOLER
AFTERNOON HIGHS WITH NEAR 80F FOR VALLEY LOCATIONS WITH MAINLY 70S
FOR THE ENTIRE CWFA.
FRI NIGHT...A PLEASANT EVENING IS EXPECTED WITH GRADUAL CLEARING
TO MOSTLY CLEAR SKIES AND CALM WINDS...AS THE SFC HIGH MOVES OVER
NY AND NEW ENGLAND. IDEAL RADIATIONAL COOLING CONDITIONS WILL
OCCUR...AND LOWS WILL BE MAINLY IN THE LOWER TO M50S WITH A FEW
U40S IN THE SRN DACKS. SOME PATCHY OR AREAS OF RADIATIONAL FOG MAY
FORM...AND MAY NEED TO BE ADDED TO THE FCST LATER IN TIME FOR MORE
WIDESPREAD FOG.
SATURDAY...A GOOD DEAL OF SUNSHINE AS TEMPS WILL BE SLIGHTLY
WARMER THAN FRIDAY WITH A MID AND UPPER LEVEL RIDGE BUILDING IN
OVER THE NORTHEAST. A CLOSED ANTICYCLONE MAY SET UP OVER NY AND
NEW ENGLAND LATE IN THE DAY. H925-850 TEMPS REBOUND BACK INTO THE
MID TEENS CELSIUS ALONG WITH INCREASING SUBSIDENCE WITH THE MID
AND UPPER RIDGE...AND THE SFC ANTICYCLONE FOR 80S IN THE VALLEYS
AND 70S FOR THE TERRAIN.
SATURDAY NIGHT...BIG BUBBLE...LITTLE TROUBLE AS THE COMBINATION OF
CLEAR SKIES...CALM WINDS AND LONGER NOCTURNAL PERIOD SHOULD ALLOW
FOR RADIATIONAL FOG TO FORM ONCE AGAIN AND COULD BE EVEN MORE
WIDESPREAD. THIS WILL CONTINUE TO BE MONITORED AND EVALUATED IN
LATER FORECASTS. LOWS MAINLY INTO THE 50S FOR THE REGION.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
THE LONG TERM PORTION OF THE FORECAST WILL FEATURE ABOVE NORMAL
TEMPERATURES AND BELOW NORMAL PRECIPITATION...CONTINUING THE TREND
FROM THE SHORT TERM.
A RIDGE OF HIGH PRESSURE AT ALL LEVELS OF THE ATMOSPHERE WILL
PROVIDE THE DRY AND VERY WARM CONDITIONS THROUGH AT LEAST LABOR DAY.
500 MB HEIGHTS AND 850 MB TEMPERATURES ARE FORECAST TO BE +1 TO +2
STDEV ACCORDING TO THE GEFS WHICH WILL RESULT IN MID LEVEL CAPPING
SUPPRESSING CONVECTION WITH PLENTY OF SUNSHINE. NORMAL HIGH
TEMPERATURES FOR ALBANY BY EARLY NEXT WEEK WILL BE THE MID
70S...HOWEVER WE WILL EXPERIENCE TEMPERATURES IN THE MID TO UPPER
80S...WITH SOME TEMPS POSSIBLY APPROACHING 90 IN PORTIONS OF THE MID
HUDSON VALLEY BY MONDAY. OVERNIGHT LOW TEMPERATURES SHOULD FALL INTO
THE 50S TO LOWER 60S FOR MON AM...THEN MAINLY LOWER/MID 60S FOR MON
NT/TUE AM ALTHOUGH SOME 50S COULD STILL OCCUR IN PORTIONS OF THE
ADIRONDACKS AND EASTERN CATSKILLS...AS WELL AS PORTIONS OF THE
SOUTHERN GREENS AND IN THE BERKSHIRES. HUMIDITY LEVELS SHOULD REMAIN
SOMEWHAT COMFORTABLE THROUGH MONDAY.
THE NEXT CHANCE OF ANY PRECIPITATION ARRIVES ON TUESDAY AS A
WEAKENING FRONTAL BOUNDARY APPROACHES FROM THE NORTH AND WEST.
LATEST MODELS SUGGEST THAT THIS FRONT WEAKENS QUITE A BIT BEFORE
REACHING OUR REGION...AS THE BEST UPPER LEVEL SUPPORT SHEARS WELL N
AND W OF THE REGION. THIS ENERGY SHOULD FLATTEN OUT THE UPPER LEVEL
RIDGE A BIT. WILL ONLY INCLUDE SOME SLIGHT CHANCE TO LOW CHC POPS
FOR THE ADIRONDACKS FOR LATE TUE...AND SLIGHT CHC TUE NT INTO WED
FOR MAINLY THE NORTHERN HALF OF THE REGION. TUESDAY MAX TEMPS SHOULD
STILL REACH THE MID/UPPER 80S FOR MOST AREAS...EXCEPT FOR LOWER 80S
ACROSS HIGHER ELEVATIONS. ONLY SLIGHTLY COOLER CONDITIONS WILL OCCUR
BEHIND THE FRONT...LEAVING WELL ABOVE NORMAL READINGS TO PERSIST.
OVERNIGHT MINS FOR TUE NT/WED AM SHOULD FALL INTO THE LOWER/MID
60S...EXCEPT FOR 50S ACROSS SOME HIGHER ELEVATIONS.
THERE ARE SOME INDICATIONS THAT A STRONGER COLD FRONT MAY APPROACH
THE REGION LATE NEXT WEEK...BUT THIS REMAINS UNCERTAIN. FOR NOW...
ABOVE NORMAL TEMPERATURES CAN BE EXPECTED TO CONTINUE THROUGH THE
NEXT 7-10 DAYS.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
A WEAK COLD FRONT WILL SETTLE SOUTHWARD ACROSS THE TAF SITES THIS
AFTERNOON/EARLY EVENING. ISOLATED SHOWERS/THUNDERSTORMS WILL BE
POSSIBLE WITH OR JUST AHEAD OF THIS FRONT.
AREAS OF LOW CLOUDS/FOG SHOULD DISSIPATE AT KGFL AND KPSF BETWEEN
12Z-14Z/THU. THEREAFTER...VFR CONDITIONS ARE EXPECTED...OUTSIDE
OF ISOLATED SHOWERS/THUNDERSTORMS WHICH SHOULD DEVELOP BETWEEN
18Z- 22Z/THU. MOST OF THE CONVECTION IS EXPECTED TO REMAIN WEST
AND EAST OF THE TAF SITES...BUT CAN NOT RULE OUT A COUPLE
IMPACTING THE TAF SITES LATER THIS AFTERNOON. BRIEF PERIODS OF
MVFR/IFR VSBYS COULD OCCUR WITHIN THE CORES OF ANY
SHOWERS/THUNDERSTORMS.
CONVECTION SHOULD DECREASE AFTER 00Z/FRI...WITH MAINLY VFR
CONDITIONS CONTINUING THROUGH 06Z/FRI.
SOME LOW CLOUDS MAY DEVELOP AND/OR SPREAD WESTWARD BETWEEN 09Z-
12Z/FRI...ESP AT KPSF AND KPOU. GENERALLY MVFR CIGS WILL BE
POSSIBLE...ALTHOUGH KPSF COULD APPROACH IFR CIGS.
LIGHT/VARIABLE WINDS SHOULD PERSIST THROUGH 13Z/THU...THEN TREND
INTO THE NORTH TO NORTHWEST AT 5-10 KT THIS AFTERNOON. WINDS WILL
THEN SHIFT INTO THE N TO NE BETWEEN 01Z-04Z/FRI IN THE WAKE OF THE
COLD FRONT...AT 5-10 KT...ALTHOUGH COULD BRIEFLY GUST INTO THE
10-20 KT RANGE...ESP AT KGFL DUE TO CHANNELING DOWN THE UPPER
HUDSON/CHAMPLAIN VALLEY AND LAKE GEORGE.
OUTLOOK...
THU NT-LABOR DAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
OUR RECENT DRY WEATHER...AND MORE EXPECTED IN THE
FORECAST...CONTINUES TO BE MONITORED. HOWEVER...LOW LEVEL MOISTURE
REMAINS ELEVATED AND WITH THE APPROACH OF A WEAK COLD FRONT COULD
TOUCH OFF ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS LATER
THIS MORNING INTO THE AFTERNOON HOURS. MOST OF THIS ACTIVITY
SHOULD DISSIPATE FOR THE REGION TONIGHT BUT A SHOWER OR TWO MAY
LINGER SOUTH OF I90 INTO FRIDAY.
THE RH VALUES WILL FALL TO 45-60 PERCENT THIS AFTERNOON. AN
EXCELLENT RECOVERY IS LIKELY FRIDAY MORNING WITH MAXIMUM RH VALUES
ONCE AGAIN OF 90 TO 100 PERCENT.
THE WINDS WILL BE LIGHT AND VARIABLE IN DIRECTION THIS MORNING.
THE WINDS WILL THEN SHIFT TO THE NORTHWEST TO NORTH AT 5-15 MPH
THIS AFTERNOON...AND THEN WILL BECOME NORTH TO NORTHEAST AT 5 TO
10 MPH BY THIS EVENING.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED THE NEXT 5 DAYS ENDING LABOR DAY.
ISOLATED TO SCATTERED SHOWERS AND OR THUNDERSTORMS WILL BE
POSSIBLE TODAY...AS A BACKDOOR COLD FRONT MOVES SOUTHWARD ACROSS
THE REGION....OTHERWISE IT WILL BE DRY THROUGH THE PERIOD.
RAINFALL AMOUNTS MAY RANGE FROM A TENTH TO QUARTER INCH WITH
LOCALLY HIGHER AMOUNTS FROM ANY THUNDERSTORMS.
ABOVE NORMAL TEMPERATURES WILL CONTINUE THROUGH THE
HOLIDAY WEEKEND...AS HIGH PRESSURE DOMINATES. RIVER FLOWS WILL
REMAIN BELOW NORMAL FOR EARLY SEPTEMBER.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR
WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...BGM
NEAR TERM...BGM
SHORT TERM...BGM/WASULA
LONG TERM...KL/JPV
AVIATION...KL
FIRE WEATHER...BGM/WASULA
HYDROLOGY...BGM/WASULA
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
913 AM EDT THU SEP 3 2015
.UPDATE...SFC DATA SHOWS WEAK LOW PRES NEAR THE SE GA COAST WITH
TROUGHING EXTENDING SW INTO THE FL BIG BEND AND INTO THE NE GULF
OF MEXICO. UPPER LEVEL FORCING NOTED NEAR THE GA COAST WITH VORT
MAX IN NW TO W FLOW...WITH WEAK MID LEVEL RIDGE OVER SW GA IN THE
WAKE OF THIS FEATURE. ANOTHER SHORTWAVE IN WATER VAPOR AND RUC
ANALYSIS THAT IS PRETTY WELL DEFINED WAS OVER ERN/SERN AL MOVING
EWD THAT WILL LIKELY AFFECT OUR WX LATER TODAY.
CURRENTLY AREAS OF LOW CLOUDS ARE IN SE GA WITH SOME PATCHY FOG
THIS IS BEGINNING TO LIFT. CONVECTION ASSOCD WITH REMNANT LOW ARE
OFF THE SE GA COAST AND WILL CONTINUE TO PUSH OUT TO SEA FURTHER.
PRIOR FCST OF ISOLD TO SCT SHOWERS AND ISOLD STORMS LOOKS GOOD
THOUGH WILL TWEAK THEM UP SLIGHTLY TO BASED ON HRRR MODEL RUNS
AND 12Z SOUNDING SHOWING PWAT 2.15 INCHES AND LI OF -7. THINK MOST
IF NOT ALL RAIN CHANCES WILL BE IN THE AFTN HOURS WITH SUBSIDENCE
ON THE BACK SIDE OF LOW/VORT MAX OFFSHORE TO LIMIT CONVECTIVE
POTENTIAL UNTIL DAYTIME HEATING LEADS TO INSTABILITY. SHORTWAVE
COMING INTO OUR LATE TODAY AND TONIGHT MAY INCREASE OUR RAIN
CHANCES AROUND THE 4 PM TO 10 PM TIME FRAME AND WILL BE MONITORED
DURING THE DAY.
&&
.AVIATION...LIFR TO IFR CIGS THIS MORNING ARE MAINLY LIMITED AT
THIS TIME TO JAX...SSI AND CRG WITH MVFR CIGS BY 15Z/16Z. REST OF
TAFS VFR AT THIS TIME. A FEW SHOWERS AND STORMS MAY IMPACT
TERMINALS THIS AFTN BUT LOW PROBABILITIES SUGGEST KEEPING VCTS AT
THIS TIME. OVERALL LOWER CHANCES OF SHOWERS AND STORMS THAN PRIOR
DAYS.
&&
.MARINE...
WEST TO NORTHWEST FLOW NEAR 10 TO OCNL 15 KT THIS MORNING WILL
DECREASE THIS AFTN. SEAS 2-3 FT. SCATTERED SHOWERS AND STORMS
POSSIBLE THIS AFTN ACROSS THE REGIONAL ATLANTIC WATERS. MINOR
TWEAKS IN THE UPDATED CWF.
RIP CURRENTS: LOW SEAS AND WEAK WINDS WILL ALLOW FOR RISK
THROUGH EARLY FRIDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 91 73 94 73 / 30 20 30 20
SSI 86 76 89 76 / 30 20 30 30
JAX 89 75 92 73 / 30 20 40 30
SGJ 91 75 89 75 / 30 20 40 30
GNV 92 73 92 72 / 30 30 50 40
OCF 92 74 91 73 / 40 30 50 40
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...NONE.
&&
$$
SHASHY/WALSH
AREA FORECAST DISCUSSION
NWS PADUCAH KY
641 AM CDT THU SEP 3 2015
.UPDATE...
Issued at 641 AM CDT THU SEP 3 2015
The AVIATION section has been updated for the 12Z TAF issuance.
&&
.SHORT TERM...(Today through Saturday)
Issued at 327 AM CDT THU SEP 3 2015
The 00Z models try to pinch the upper ridge from the east Friday
into Saturday, which leads to a little bit more pronounced surface
ridging by Saturday. The models are spitting out QPF just
northeast of our region, especially Friday night, but MOS PoPs are
mostly single digits. Won`t be surprised if we end up with some
PoPs Friday night or Saturday, but for now will just mention it
here and keep the forecast dry, and in line with neighboring
offices.
A literal handful of showers and one brief thunderstorm developed
across the forecast area yesterday afternoon. They were short-
lived, and with one exception, did not produce lightning. The 00Z
ARW and NMM WRF runs both generate some isolated convection across
the region this afternoon, and the latest HRRR shows some isolated
weak showers. With that support, will play the persistence card and
add isolated showers and storms to all but the far northwest and
western fringes of the area this afternoon. Will wait and see
what happens this afternoon before considering it for Friday
afternoon.
Temperatures climbed toward the warmer MAV/EC guidance yesterday
afternoon, so will continue to go that way with high temperatures
today and Friday. The 00Z MAV has 97 for Paducah Friday, but that
seems a bit spurious compared to surrounding MOS sites. Saturday
is a bit less clear cut, with the upper ridge weakening and
indications of a minor surge of surface high pressure over the
Evansville Tri State.
Stayed on the warm side of guidance Saturday over the Tri State,
but that does result in a couple of degrees of cooling from
Friday`s levels. Outside of the Tri State, Saturday could be just
as warm as Friday. The humidity is nothing like we had mid-summer,
but it could be just enough to allow heat indices to approach 100
in a few locations each afternoon.
Low temperatures tonight will be similar to this morning`s lows,
which are a bit lower than the consensus of guidance in most
locations. Lows Friday night may be closer to the consensus with
more wind expected.
.LONG TERM...(Saturday Night through Wednesday)
Issued at 327 AM CDT THU SEP 3 2015
The deterministic runs of the med range models have been somewhat
unstable of late, and the latest GFS 500 mb height spaghetti pattern
shows significantly increased chaos by Tue (Day 6), though the
latest GFS/ECMWF ensemble means appear quite similar overall. This
will affect confidence in the latter period forecast, regarding
impulses of energy in the nrn stream which may or may not produce a
secondary sfc front in our region.
Early in the extended period, the PAH forecast area will be affected
by an amplified srn stream pattern, with ridging aloft west of the
MS River and troffing over the Atlantic seaboard. Meanwhile, by Mon,
a cold front is progged to impinge on the ridge over our region.
There might be enough lift to produce a few showers and tstms in the
nwrn half of our region Mon afternoon, perhaps progressing a bit
farther sewd Mon night. The latest ECMWF appears to break down the
ridge more than the GFS by Tue, and is therefore more generous with
its QPF into Wed. For now, we downplayed PoPs a bit for Mon/Mon
night because of the lingering mid/upper ridge, then went generally
with the model initialization blend after that, which provided no
more than 40% PoPs for any 12 hour period. At this time, it appears
that model consensus and HPC point toward a bona fide sfc fropa at
the very end of the present Day 7 (Wed).
Expect above average temps through the extended period, slowly
decreasing by Day 7 to near seasonable levels.
&&
.AVIATION...
Issued at 641 AM CDT THU SEP 3 2015
A few isolated showers or thunderstorms will be possible again across
the region this afternoon, but the coverage is expected to be too
sparse to mention in any of the TAFs. Otherwise, the only concern
to aviaton is more fog potential at all terminals late tonight.
Guidance is too pessimistic at KCGI, and figure that persistence
should be pretty close. Used it as a guide in mentioning
prevailing MVFR fog at all sites in the last few hours of the
forecast.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...DRS
SHORT TERM...DRS
LONG TERM...DB
AVIATION...DRS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
740 AM EDT THU SEP 3 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 412 AM EDT THU SEP 3 2015
THE RAIN OVER THE SOUTHERN AND EASTERN PART OF THE FORECAST AREA
FINALLY SEEMS TO BE MOVING OUT OF THE AREA AS THE UPPER SHORT WAVE
MOVES EAST. THE BIG PROBLEM THIS MORNING IS ACTUALLY DENSE FOG
ACROSS THE WESTERN PART OF THE FORECAST AREA WHERE IT HAS CLEARED
OUT WITH SUFFICIENT LOW LEVEL MOISTURE FROM RAINFALL OVER THE PAST
24 HR. MOST OF THE WESTERN TIER OF COUNTIES HAVE VSBYS LESS THAN ONE
QUARTER OF A MILE AND AS SUCH HAVE OPTED TO GO WITH A DENSE FOG
ADVISORY FOR THIS AREA UNTIL 14Z.
OTHERWISE...AS THE UPPER SHORT WAVE SLOWLY MOVES EAST THIS
MORNING...EXPECT ANY REMAINING SHOWERS TO MOVE OUT OF THE AREA AS
WELL. THE RAP SUGGESTS THAT CYCLONIC FLOW WILL PERSIST THROUGH THE
DAY ACROSS THE EAST. THIS COMBINED WITH LAKE BREEZE CONVERGENCE
ACROSS THE EAST IMPLIES AT LEAST A SLIGHT CHANCE OF SHOWERS THIS
AFTERNOON ACROSS THE FAR EAST. NOT TOO EXCITED ABOUT THUNDERSTORM
CHANCES AS LOCAL RESEARCH SUGGESTS VERY MIMINAL THUNDERSTORM
DEVELOPMENT WITH NORTHERLY MID LEVEL FLOW. ACROSS THE REMAINDER OF
THE AREA...MINIMAL MLCAPE VALUES OF LESS THAN 300 J/KG PER THE
RAP...DRY AIR ASSOCIATED WITH THE HIGH PRES AND BUILDING HEIGHTS
SHOULD PRECLUDE ANY SHOWER/THUNDERSTORM DEVELOPMENT. DESPITE THE
NORTH-NORTHEAST FLOW...IT WILL STILL REMAIN MILD AND RATHER STICKY
WITH HIGHS IN THE UPPER 70S/LOWER 80S...STILL ABOVE NORMAL FOR EARLY
SEPTEMBER.
WITH HIGH PRESSURE IN CONTROL...IT SHOULD BE A QUIET NIGHT TONIGHT.
CANNOT RULE OUT MORE FOG DEVELOPMENT ACROSS THE INTERIOR WITH LIGHT
WINDS AND CLEAR SKIES. TEMPS SHOULD DROP INTO THE UPPER 50S/LOWER
60S.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 452 AM EDT THU SEP 3 2015
PRIME CONCERNS IN LONG TERM INCLUDE EXTENT/STRENGTH OF SHRA/TSRA
THIS WEEKEND INTO LABOR DAY AND MAX TEMPS. FOG WILL ALSO BE ISSUE
AT TIMES WITH HUMID AIRMASS PERSISTING UNTIL COLD FRONT ARRIVES BY
LABOR DAY.
UPPER RIDGE BUILDS BACK OVER UPPER GREAT LAKES ON FRIDAY. REMNANT OF
SHORTWAVE THAT IS MOVING THROUGH ATTM MEANDERS OVER LOWER MICHIGAN
AND MAY DRIFT TOWARD EAST CWA BY EVENING. GFS/NAM SOUNDINGS SEEM TOO
DRY FOR SHRA/TSRA WITH GENERAL EAST SFC WINDS COMING OUT OF HIGH
OVER QUEBEC. SLIGHTLY DRIER TOO WITH UPR 50S TO LOW 60S DWPNTS
INSTEAD OF UPR 60S-NEAR 70. COULD BE FOG AROUND TO START DAY BUT
THAT SHOULD GIVE WAY TO MOSTLY SUNNY SKIES BY LATE MORNING. TEMPS
HELD DOWN BY OVERALL FLOW OFF THE GREAT LAKES AND COOLER TEMPS
ALOFT. EXPECT MID 80S INTERIOR WEST AND UPR 70S NEAR 80 OVER REST OF
CWA.
EDGE OF UPPER RIDGE DRAWS CLOSE ENOUGH FRIDAY NIGHT INTO SATURDAY TO
BRING SHRA/TSRA POSSIBILITY BACK TO THE AREA...ADVECTING IN FM
NORTHERN PLAINS WITH SW MEAN LAYER H85-H3 WINDS. EDGE OF MUCAPE OVER
1000J/KG AS CLOSE AS NORTHERN MN AND NORTHERN WI. ECMWF AND GFS ALSO
BOTH SHOWING SHORTWAVE CURRENTLY OVER FOUR CORNERS TRACKING OVER
NORTHERN MN AND LK SUPERIOR BY 12Z SATURDAY. INCREASING H85 JET
RAMPS UP MOISTURE ADVECTION OVER MN SO HAVE PUT CHANCE POPS OVER
WESTERN LK SUPERIOR ON FRIDAY NIGHT AND SPREAD THEM INTO FAR WEST
CWA ON SATURDAY AS THERE MAY BE GREATER CHANCE OF SHRA/TSRA IN VCNTY
OF THE SHORTWAVE AND GIVEN THE HIGHER MUCAPES. MLCAPES ALSO PUSH UP
TOWARD 1000J/KG DURING AFTN SO THERE MAY BE ADDITIONAL SHRA/TSRA TRY
TO FORM DUE TO DAYTIME HEATING AND POSSIBLY AFFECTS FM THE
SHORTWAVE. PROBABLY WILL BE SOME FOG AROUND TO START DAY AGAIN. SE
WINDS ADDING MOISTURE OFF LK MICHIGAN AND RADIATIONAL COOLING FRIDAY
NIGHT SHOULD LEAD TO BEST BET FOR FOG OVER INTERIOR CNTRL AND NEAR
LK MICHIGAN. ONCE FOG EVADES...PARTLY SUNNY SKIES WILL ALLOW TEMPS
TO WARM QUITE A BIT OVER FRIDAY. H85 TEMPS PUSHING 19-20C BY AFTN
AND MORE OF A SOUTH WIND COMPARED TO FRIDAY POINT TO MID-UPR 80S FOR
MOST WITH A FEW 90 DEGREE READINGS POSSIBLE INTERIOR WEST AND NEAR
LK SUPERIOR WITH DOWNSLOPING WINDS.
STRONGER SHORTWAVE LIFTS OVER UPPER MISSISSIPPI RIVER VALLEY SAT
NIGHT IN SW FLOW ALOFT. AT SFC...LOW PRESSURE SYSTEM WILL BE
DEVELOPING OVER HIGH PLAINS WHILE TROUGHING EXTENDS ACROSS NORTHERN
PLAINS AND TO NORTHWEST ONTARIO. SOUTH WINDS AHEAD OF TROUGH SHOULD
LEAD TO WARM/MUGGY NIGHT OVER UPR MICHIGAN. MUCAPES REMAIN HIGH AT
1000-2000J/KG FM NORTHERN PLAINS ACROSS UPPER GREAT LAKES. IF
SHORTWAVE TRACKS CLOSE ENOUGH...COULD SEE SHRA/TSRA PUSH OVER WEST
HALF OF CWA AT LEAST WITH H85-H3 WINDS FM THE WSW. UNLIKE FRIDAY
NIGHT WITH SIMILAR SETUP...SHEAR IS FORECAST TO BE MUCH STRONGER AS
1-6KM SHEAR VALUES ARE 30-40 KTS. LOW-LEVEL JET AT H85 OVER 40 KTS
IS AIMED TOWARD UPPER MISSISSIPPI RIVER VALLEY AND AT LEAST WESTERN
FRINGE OF UPPER GREAT LAKES. NOT SURE IF GREATER MLCAPES WELL TO SW
OF HERE WILL KEEP MAIN SHRA/TSRA THERE SINCE THE SHORTWAVE IS MUCH
FARTHER NORTH. CARRIED CHANCE POPS OVER WEST CWA...SLIGHT CHANCES
FARTHER EAST. GIVEN THE SHEAR AND INSTABILITY...THERE IS AT LEAST A
REMOTE CHANCE OF STRONG TO SEVERE STORMS AS SHOWN BY LATEST DAY3
OUTLOOK FM SPC.
STRONG SHORTWAVE SLIDES FM ROCKIES TO THE NORTHERN PLAINS SUNDAY
INTO SUNDAY NIGHT. ASSOCIATED SFC LOW BOTTOMS OUT AT 990-1000MB OVER
SOUTHERN MANITOBA BY MONDAY MORNING. MOISTURE ADVECTION AND
CONTINUAL FEED OF STRONG INSTABILITY SHOULD SUPPORT MULTIPLE CLUSTERS
OF SHRA/TSRA WITHIN H85 JET AXIS AND JUST AHEAD OF SFC FRONT. NEVER
SURE HOW FAR SHRA/TSRA WILL BREAK OUT AHEAD OF MAIN FRONT AS WITHOUT
STRONG FORCING FM A YET TO BE DETERMINED SHORTWAVE THERE CAN ALWAYS
BE CAPPING CONCERNS. WILL CONTINUE TO HIGHLIGHT WEST CWA FOR BETTER
CHANCES AT THIS POINT WITH WSW MEAN LAYER WINDS. ANOTHER WARM AND
HUMID DAY AHEAD OF THE FRONT. H85 RIDGE AHEAD OF THE FRONT POINTS TO
READINGS SIMILAR TO SAT AS LONG AS CLOUDS/SHRA/TSRA DONT DISRUPT
THINGS TOO MUCH. PUT THE WARMEST TEMPS ON SUNDAY OVER CNTRL CWA
CLOSER TO LK SUPERIOR WITH DOWNSLOPING SOUTH WINDS. BEST CHANCE FOR
READINGS TO HIT 90 DEGREES WOULD BE BARAGA/BIG
BAY/MARQUETTE/HARVEY/MUNISING.
ALL THIS SHRA/TSRA ACTIVITY SHOULD EASE EAST ACROSS REST OF CWA AS
THE MAIN SFC-H85 FRONTS AND ASSOCIATED THETA-E RIDGE AND RIBBON OF
PWATS OVER 1.75 INCHES CROSS SUNDAY NIGHT INTO MONDAY. MLCAPES OVER
1000J/KG INITIALLY BUT THESE TAIL OFF WITH NIGHTTIME COOLING.
MUCAPES WELL OVER 1000J/KG MAY ALLOW STORMS TO TRY TO BECOME
ELEVATED AFTER BECOMING SFC BASED...BUT THAT IS ALWAYS A TRICKY
TRANSITION. STRONG H85 JET AND MOISTURE TRANSPORT INTO THE AREA
OF HIGHER MUCAPES WILL AID THIS TRANSITION THOUGH. CONSENSUS HIGH
CHANCE TO LOW-END LIKELY POPS SEEMED FINE FOR SUNDAY NIGHT. BETTER
POPS ON LABOR DAY END UP BEING OVER EAST HALF WITH GREATER MOISTURE
ADVECTION AHEAD OF THE EXITING SFC-H85 FRONT. H85 TEMPS DO NOT CRASH
DOWN AS IT LOOKED LIKE A FEW DAYS AGO...SO UPR 70S TO LOW OR
POSSIBLY MID 80S WILL WORK FOR TEMPS ON MONDAY. WARMEST READINGS
CNTRL CWA IRON MTN TO MARQUETTE AND MUNISING. THROUGH THE COOLING IS
NOT AS SIGNIFICANT...THE DRYING IS WITH DWPNTS FALLING OFF INTO THE
50S ON MONDAY AFTN OVER THE WEST AND DOWN TO AROUND 50 BY LATE
MONDAY NIGHT. COULD EVEN SEE 40S DWPNTS ON TUESDAY AS COOLING
BECOMES MORE PRONOUNCED. EXPECT HIGHS UPR 60S TO LOW 70S ON TUE AND
THEN MAINLY IN THE 60S FOR WED. GUSTY WINDS AS THE COOLING OCCURS
ESPECIALLY NEAR LK SUPERIOR. NEXT CHANCE OF RAIN PRETTY WELL AGREED
UPON BY GFS AND ECMWF FOR TUE NIGHT INTO WED MORNING.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 740 AM EDT THU SEP 3 2015
LIFR/VLIFR CONDITIONS WILL PERSIST AT IWD AND CMX FOR THE NEXT HOUR
OR TWO BEFORE CLEARING. CONDITIONS AT SAW HAVE JUST LOWERED TO
IFR...BUT THE EXPECTATION IS THAT THEY WILL ALSO SEE MVFR THEN VFR
SOON AFTER SUNRISE. OTHERWISE...AFTER THE MORNING FOG AND LOW
STRATUS...EXPECT VFR CONDITIONS THROUGH THIS EVENING. CLEAR SKIES
AND LIGHT WINDS WILL LIKELY CAUSE IFR CONDITIONS ONCE AGAIN LATER
TONIGHT INTO FRIDAY MORNING AT ALL SITES.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 412 AM EDT THU SEP 3 2015
DENSE FOG HAS DEVELOPED ACROSS THE WESTERN HALF OF THE
LAKE...ESPECIALLY OVER AREAS THAT SAW RAIN YESTERDAY. AS SUCH...HAVE
ISSUED A DENSE FOG ADVY FOR THE ENTIRE WEST HALF OF THE LAKE THROUGH
EARLY THIS AFTERNOON. OTHERWISE...NORTHEAST WINDS OF 10-15KT WILL
CONTINUE TODAY WITH 1-3 FT WAVES ACROSS THE WEST. THE NEXT CHANCE
FOR WINDS GREATER THAN 20KT WILL BE SUNDAY INTO MONDAY AS THE NEXT
SYSTEM APPROACHES FROM THE WEST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
DENSE FOG ADVISORY UNTIL 10 AM EDT /9 AM CDT/ THIS MORNING FOR
MIZ001>003-009-084.
LAKE SUPERIOR...
DENSE FOG ADVISORY UNTIL 2 PM EDT /1 PM CDT/ THIS AFTERNOON FOR
LSZ162-240>248-263>265.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...MRD
LONG TERM...JLA
AVIATION...MRD
MARINE...MRD
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
608 AM EDT THU SEP 3 2015
.SYNOPSIS...
ABOVE NORMAL TEMPERATURES ARE EXPECTED TODAY THROUGH FRIDAY. A WEAK
TROUGH WILL LINGER IN THE AREA THROUGH EARLY FRIDAY. A RIDGE OF HIGH
PRESSURE WILL BUILD IN FROM THE NORTH BEHIND A COLD FRONT THIS
WEEKEND...BRINGING UNSETTLED WEATHER AND COOLER TEMPERATURES THROUGH
THE FIRST PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 615 AM THURSDAY...LAST OF THE CONVECTION IS NOW MOVING
OFFSHORE NORTHERN PENDER COUNTY. THAT SHOULD END THE THUNDERSTORM
THREAT...REMOTE THOUGH IT MAY HAVE BEEN...UNTIL THIS AFTERNOON.
PREVIOUS DISCUSSION FOLLOWS:
GUST FRONT FROM CONVECTION UP NORTH MOVING THROUGH OUR NORTH
CAROLINA COUNTIES AT THIS TIME. WINDS ARE NOT STRONG...BUT AT 5 TO
10 KTS ARE CREATING A NOTICEABLE WIND SHIFT. ASSOCIATED CONVECTION
STILL TO OUR NORTH BUT MAY SCRAPE PENDER COUNTY BEFORE MOVING
OFFSHORE.
WEAK PRESSURE PATTERN AND ABOVE-NORMAL TEMPERATURES CONTINUE FOR
ANOTHER DAY. PIEDMONT-STYLE THERMAL TROUGH TO OUR WEST STRENGTHENS
TODAY AND ALSO EXPECT THE DIURNALLY DRIVEN SEA BREEZE CIRCULATION TO
SET UP THIS AFTERNOON. A MODERATELY UNSTABLE COLUMN WILL DEVELOP
THIS AFTERNOON AND WITH PLENTIFUL AVAILABLE MOISTURE...WITH P/W
VALUES CLOSING IN ON 2 INCHES...STILL EXPECTING SCATTERED CONVECTION
TO DEVELOP. INITIAL FOCUS OF CONVECTION...FOR LACK OF AN OTHER
STRONG TRIGGERS...WILL BE ALONG THE SEA BREEZE FRONT THIS AFTERNOON.
DIURNALLY DRIVEN CONVECTION WILL FADE WITH THE SUNSET.
ABOVE NORMAL TEMPERATURES WILL CONTINUE AND WITH DEWPOINTS RANGING
FROM THE UPPER 60S TO MID 70S EXPECT APPARENT TEMPERATURES TO PEAK
AT AROUND 100 DEGREES THIS AFTERNOON. OVERNIGHT MINIMUMS PROJECTED
IN THE LOWER TO MID 70S.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 230 AM THURSDAY...H5 RIDGE AXIS IS SHOWN TO EXTEND FROM THE
SOUTHERN PLAINS AND LOWER MS VALLEY INTO THE MID WEST AND GREAT
LAKES REGION EARLY FRIDAY WITH A WEAK TROUGH ORIENTED NEARLY EAST-
WEST FROM THE MID-ATLANTIC REGION TOWARD THE OHIO VALLEY. THE H5
TROUGH WILL DRIFT SOUTH ACROSS THE SOUTHEASTERN STATES WITH SOME
DURING SATURDAY AS HIGH PRESSURE ALOFT EVOLVES ACROSS NEW ENGLAND.
AT THE SURFACE...A RIDGE WILL BUILD SOUTH ACROSS THE FORECAST AREA
FRIDAY NIGHT INTO SATURDAY BRINGING AN END TO THE ATYPICALLY WARM
TEMPERATURES. THE PRECIPITABLE WATER DOES NOT STAND OUT AS IT IS
EXPECTED TO AVERAGE A LITTLE OVER AN INCH AND A HALF EACH DAY. AN
INCREASE IN LOW-LEVEL CONVERGENCE ON SATURDAY IN NORTHEASTERLY FLOW
TRANSLATES TO SLIGHTLY HIGHER POPS COMPARED TO FRIDAY IN AN
ENVIRONMENT THAT IS UNSETTLED...BUT DEVOID OF A SIGNIFICANT LIFTING
MECHANISM.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 230 AM THURSDAY...WEAK/BROAD AREA OF LOW PRESSURE NOTED IN
500MB PROGS WILL LINGER OVER THE SOUTHEAST UNITED STATES SUNDAY
RESULTING IN A CONTINUATION OF UNSETTLED WEATHER THROUGH TUESDAY AS
IT GRADUALLY WEAKENS OVER THE REGION. THE SURFACE RIDGE WEAKENS
ACROSS THE CAROLINAS AS WELL DURING THE PERIOD WITH LOWER PRESSURE
LINGERING OFF THE COAST. ALTHOUGH THE PRECIPITABLE WATER IS EXPECTED
TO INCREASE TO JUST UNDER TWO INCHES BY MONDAY THE HIGHEST
PRECIPITABLE WATER WILL CONTINUE TO BE SUPPRESSED OFFSHORE TO THE
SOUTHEAST AND SOUTH OF THE AREA. EXPECTING SCATTERED SHOWERS AND A
FEW TSTMS EACH DAY WITH THE BEST CHANCES MONDAY COINCIDENT WITH THE
HIGHEST PRECIPITABLE WATER. MAX TEMPERATURES EACH DAY WILL RANGE
WITHIN A COUPLE DEGREES OF CLIMATOLOGY WHILE THE MINS REMAIN A
COUPLE CATEGORIES ABOVE NORMAL.
&&
.AVIATION /10Z THURSDAY THROUGH MONDAY/...
AS OF 06Z...THE HRRR MODEL HAS BEEN FAIRLY CONSISTENT IN BRINGING
SOME CONVECTION FROM THE NORTHWEST...ASSOCIATED WITH A MODERATE
VORT MAX DROPPING IN FROM VIRGINIA. THE CONVECTION WILL LIKELY
DISSIPATE BY 10-11Z AS IT MOVES OFF THE COAST OF SOUTHEAST NORTH
CAROLINA. THIS IS MAINLY LEANING ON THE NAM MODEL AS THE GFS
SHIFTS THE PRECIP OFFSHORE BEFORE IT GETS HERE. TOOK OUT THE TEMPO
LOWER FOG AT LBT AS THERE WILL LIKELY BE TOO MANY CLOUDS TO
RADIATE EFFECTIVELY. THURSDAY...ANOTHER HOT DAY WITH WEST
NORTHWEST FLOW. SOME SCATTERED CONVECTION MAY DEVELOP AROUND MAX
HEATING...ESPECIALLY ALONG THE RESULTANT.
EXTENDED OUTLOOK...PREDOMINATELY VFR WITH BRIEF MORNING FOG AND
ISOLATED/SCATTERED AFTERNOON SHOWERS AND THUNDERSTORMS.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 615 AM THURSDAY...NO CHANGES TO THE FORECAST WITH THE LATEST
UPDATE. PREVIOUS DISCUSSION FOLLOWS:
A WEAK PRESSURE PATTERN OVER THE WESTERN ATLANTIC WILL MAINTAIN A
WESTERLY FLOW OF 10 KTS OVER THE COASTAL WATERS EARLY
TODAY...INCREASING TO 10 TO 15 KTS WITH HIGHER GUSTS NEAR SHORE
THIS AFTERNOON. WINDS WILL DECREASE BACK TO AROUND 10 KTS OR LESS
OVERNIGHT WHILE BECOMING MORE SOUTHWESTERLY. SEAS WILL STAY IN THE
2 FT RANGE THROUGH THE PERIOD.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 230 AM THURSDAY...LIGHT/VARIABLE WINDS EXPECTED WITH A WEAK
PRESSURE GRADIENT ACROSS THE WATERS FRIDAY THROUGH FRIDAY EVENING.
AS RIDGE OF HIGH PRESSURE BUILDS SOUTH INTO THE CAROLINAS EARLY
SATURDAY MORNING THE WIND WILL VEER TO THE NORTHEAST AND INCREASE TO
10 TO 15 KNOTS...POSSIBLY CLOSER TO 15 KNOTS ACROSS THE CAPE FEAR
WATERS FOR A BIT SATURDAY AFTERNOON/EVENING. SEAS WILL INCREASE TO
AROUND 3 FT OR A LITTLE HIGHER AS THE NORTHEAST WINDS INCREASE.
LONG TERM /SUNDAY THROUGH MONDAY/...
AS OF 230 AM THURSDAY...NORTHEAST WINDS WILL BEGIN TO WEAKEN DURING
SUNDAY AS THE RIDGE WEAKENS. COULD SEE ANOTHER PERIOD OF
LIGHT/VARIABLE WINDS DURING MONDAY WITH A WEAK PRESSURE GRADIENT
RETURNING TO THE AREA. SEAS AROUND 3 FT SUNDAY WILL SUBSIDE TO 2-3
FT DURING MONDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SRP
NEAR TERM...REK
SHORT TERM...SRP
LONG TERM...JDW/SRP
AVIATION...DL
MARINE...REK/SRP
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
939 AM CDT THU SEP 3 2015
.UPDATE...
ISSUED AT 939 AM CDT THU SEP 3 2015
LOW CLOUDS WEST OF THE RED RIVER ARE BEING STUBBORN AND HANGING
AROUND A BIT LONGER THIS MORNING...ALTHOUGH MOST OF THE FOG HAS
DISSIPATED. THINK THAT THE CLOUDS WILL LINGER FOR A FEW MORE HOURS
BEFORE DISSIPATING COMPLETELY THIS AFTERNOON. STILL THINK THAT THE
NORTH DAKOTA SIDE WILL GET INTO THE LOW 90S...BUT WILL MONITOR IN
CASE THE CLOUDS HANG AROUND A BIT LONGER AND KEEP US A FEW DEGREES
COOLER THAN EXPECTED.
UPDATE ISSUED AT 630 AM CDT THU SEP 3 2015
NO CHANGES NEEDED THIS MORNING. PLENTY OF LOW CLOUDS AND PATCHY
FOG WILL CONTINUE THROUGH ABOUT 14Z OR 15Z BEFORE BURNING OFF.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 330 AM CDT THU SEP 3 2015
THE MAIN CHALLENGE WILL BE CONVECTIVE CHANCES AND TEMPS. MODELS
CONTINUE IN GOOD AGREEMENT OVERALL...WITH THE ECMWF AND NAM VERY
SIMILAR AND PREFERRED.
FOR TODAY...IT WILL BE HOT WITH HEAT INDICES AROUND 100 THIS
AFTERNOON. THERE WILL BE MORNING FOG AND LOW CLOUDS THAT WE WILL
MENTION THROUGH 14Z OR SO.
ON FRIDAY...CONVECTIVE CHANCES WILL INCREASE FROM WEST TO EAST
THROUGH THE DAY. EXPECT A SHORTWAVE TO MOVE INTO THE REGION BY
FRIDAY AFTERNOON/EVENING. THERE WILL BE AMPLE MOISTURE WITH PWATS
AROUND 2 INCHES FRIDAY EVENING...AND MLCAPE AROUND 2000 J/KG. THE
STRONGER DEEP LAYERED SHEAR REMAINS TO THE WEST...BUT GIVEN FAIRLY
STRONG INSTABILITY/MOISTURE...SOME SEVERE STORMS POSSIBLE FRIDAY
AFTERNOON AND OVERNIGHT NEAR THE SFC BOUNDARY.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 330 AM CDT THU SEP 3 2015
FOR FRIDAY NIGHT THROUGH SAT NIGHT...SHOWERS AND STORMS MAY
BECOME LIKELY AS LLJ INCREASES DURING THE EVENING. A SFC BOUNDARY
WILL REMAIN NEARLY STATIONARY AND WILL LIKELY FOCUS SEVERAL ROUNDS
OF STORMS THROUGH SATURDAY NIGHT. GIVEN THE INSTABILITY AND
MOISTURE PROFILE...EVEN WITH WEAKER SHEAR A FEW SEVERE STORMS WILL
BE POSSIBLE. HEAVY RAIN COULD ALSO BECOME A THREAT NEAR AREA THAT
GET REPEATED THUNDERSTORMS GIVEN VERY HIGH PWATS NEAR 2 INCHES.
SUNDAY-WEDNESDAY...THE UPPER LOW FINALLY WILL EJECT INTO THE HIGH
PLAINS ON SUNDAY WITH A COLD FRONT PUSHING THROUGH THE REGION.
DEPENDING ON THE TIMING OF THE FRONTAL PASSAGE AND DEGREE OF
DESTABILIZATION AHEAD OF THE FRONT...SOME STRONG STORMS ARE POSSIBLE
SOMEWHERE OVER THE REGION AS THE WARM MOIST AIR MASS REMAINS IN
PLACE PRECEDING THE BOUNDARY AND DEEP LAYER WIND FIELDS STRENGTHEN.
MONDAY WILL BE MAINLY DRY...BREEZY AND COOLER AS THE SFC LOW LIFTS
INTO SOUTHERN CANADA. TEMPS WILL REMAIN ON THE COOL SIDE THROUGH MID
WEEK WITH MANY AREAS REMAINING IN THE 60S FOR HIGHS. CURRENTLY HAVE
A MAINLY DRY FORECAST TUE-WED...ALTHOUGH MODEL VARIABILITY BECOMES
MUCH GREATER DURING THIS TIME...LEADING TO LOW FORECAST
CONFIDENCE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 630 AM CDT THU SEP 3 2015
IFR/LIFR CIGS AND VSBYS CONTINUE WITH LOW CLOUDS AND PATCHY FOG.
THE HRRR SLOWLY ERODES THESE CLOUDS AND FOG AROUND 15Z...AND HAVE
GONE VFR THEREAFTER. SOME AREAS COULD HOLD ON A BIT LONGER...WITH
SOUTHERLY WINDS GUSTING OVER 20KT POSSIBLE THIS AFTERNOON.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...DK
LONG TERM...DK/MAKOWSKI
AVIATION...DK
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
630 AM CDT THU SEP 3 2015
.UPDATE...
ISSUED AT 630 AM CDT THU SEP 3 2015
NO CHANGES NEEDED THIS MORNING. PLENTY OF LOW CLOUDS AND PATCHY
FOG WILL CONTINUE THROUGH ABOUT 14Z OR 15Z BEFORE BURNING OFF.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 330 AM CDT THU SEP 3 2015
THE MAIN CHALLENGE WILL BE CONVECTIVE CHANCES AND TEMPS. MODELS
CONTINUE IN GOOD AGREEMENT OVERALL...WITH THE ECMWF AND NAM VERY
SIMILAR AND PREFERRED.
FOR TODAY...IT WILL BE HOT WITH HEAT INDICES AROUND 100 THIS
AFTERNOON. THERE WILL BE MORNING FOG AND LOW CLOUDS THAT WE WILL
MENTION THROUGH 14Z OR SO.
ON FRIDAY...CONVECTIVE CHANCES WILL INCREASE FROM WEST TO EAST
THROUGH THE DAY. EXPECT A SHORTWAVE TO MOVE INTO THE REGION BY
FRIDAY AFTERNOON/EVENING. THERE WILL BE AMPLE MOISTURE WITH PWATS
AROUND 2 INCHES FRIDAY EVENING...AND MLCAPE AROUND 2000 J/KG. THE
STRONGER DEEP LAYERED SHEAR REMAINS TO THE WEST...BUT GIVEN FAIRLY
STRONG INSTABILITY/MOISTURE...SOME SEVERE STORMS POSSIBLE FRIDAY
AFTERNOON AND OVERNIGHT NEAR THE SFC BOUNDARY.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 330 AM CDT THU SEP 3 2015
FOR FRIDAY NIGHT THROUGH SAT NIGHT...SHOWERS AND STORMS MAY
BECOME LIKELY AS LLJ INCREASES DURING THE EVENING. A SFC BOUNDARY
WILL REMAIN NEARLY STATIONARY AND WILL LIKELY FOCUS SEVERAL ROUNDS
OF STORMS THROUGH SATURDAY NIGHT. GIVEN THE INSTABILITY AND
MOISTURE PROFILE...EVEN WITH WEAKER SHEAR A FEW SEVERE STORMS WILL
BE POSSIBLE. HEAVY RAIN COULD ALSO BECOME A THREAT NEAR AREA THAT
GET REPEATED THUNDERSTORMS GIVEN VERY HIGH PWATS NEAR 2 INCHES.
SUNDAY-WEDNESDAY...THE UPPER LOW FINALLY WILL EJECT INTO THE HIGH
PLAINS ON SUNDAY WITH A COLD FRONT PUSHING THROUGH THE REGION.
DEPENDING ON THE TIMING OF THE FRONTAL PASSAGE AND DEGREE OF
DESTABILIZATION AHEAD OF THE FRONT...SOME STRONG STORMS ARE POSSIBLE
SOMEWHERE OVER THE REGION AS THE WARM MOIST AIR MASS REMAINS IN
PLACE PRECEDING THE BOUNDARY AND DEEP LAYER WIND FIELDS STRENGTHEN.
MONDAY WILL BE MAINLY DRY...BREEZY AND COOLER AS THE SFC LOW LIFTS
INTO SOUTHERN CANADA. TEMPS WILL REMAIN ON THE COOL SIDE THROUGH MID
WEEK WITH MANY AREAS REMAINING IN THE 60S FOR HIGHS. CURRENTLY HAVE
A MAINLY DRY FORECAST TUE-WED...ALTHOUGH MODEL VARIABILITY BECOMES
MUCH GREATER DURING THIS TIME...LEADING TO LOW FORECAST
CONFIDENCE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 630 AM CDT THU SEP 3 2015
IFR/LIFR CIGS AND VSBYS CONTINUE WITH LOW CLOUDS AND PATCHY FOG.
THE HRRR SLOWLY ERODES THESE CLOUDS AND FOG AROUND 15Z...AND HAVE
GONE VFR THEREAFTER. SOME AREAS COULD HOLD ON A BIT LONGER...WITH
SOUTHERLY WINDS GUSTING OVER 20KT POSSIBLE THIS AFTERNOON.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...DK
SHORT TERM...DK
LONG TERM...DK/MAKOWSKI
AVIATION...DK
AREA FORECAST DISCUSSION
NWS MEDFORD OR
859 AM PDT THU SEP 3 2015
.DISCUSSION...THE LATEST VISIBLE IMAGE SHOWS A BAND OF CLOUDS
MOVING SOUTHWEST TO NORTHEAST IN SOUTHEAST KLAMATH, LAKE EASTERN
SISKIYOU AND MOST OF MODOC COUNTY. A FEW RAWS SITES IN THESE
LOCATIONS PICKED UP LIGHT RAINFALL WITH ANYWHERE BETWEEN 0.01 AND
0.10 OF AN INCH BETWEEN LAST NIGHT AND THIS MORNING. THE RADAR
IMAGE IS NOT SHOWING ANYTHING BECAUSE THE RAIN IS OCCURRING AT
LOWER LEVELS WHICH IS NOT BEING PICKED UP. MEANWHILE A ISOLATED
SHOWERS IN ASSOCIATION WITH A WEAK SHORTWAVE TROUGH WITHIN THE
MUCH LARGER UPPER LOW IS MOVING INLAND JUST NORTH OF OUR FORECAST
AREA. THESE ISOLATED SHOWERS SHOULD REMAIN TO OUR NORTH TODAY.
THE UPPER LOW WILL MOVE SOUTH TONIGHT AND MORE SHORTWAVE ENERGY
WILL ROTATE AROUND THE UPPER LOW WITH THE FIRST IN A SERIES
EXPECTED TO SWING INTO NORTHWEST CAL EARLY FRIDAY MORNING. COLD
AIR ALOFT WITH 500MB TEMPERATURES NEAR -23C WILL OVER THE MARINE
WATERS LATE TONIGHT SO COULD NOT RULE OUT AN ISOLATED THUNDERSTORM
OR TWO.
FRIDAY WILL BE THE MOST ACTIVE DAY IN THE PERIOD AS THE UPPER LOW
AND COLD AIR ALOFT MOVES OVERHEAD WITH SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS. IT`S POSSIBLE WE COULD HAVE MORE
THUNDERSTORM ACTIVITY FRIDAY AFTERNOON EAST OF THE CASCADES. IT`S
ALSO POSSIBLE SOME THUNDERSTORMS COULD PRODUCE GUSTY WINDS AND
SMALL HAIL. -PETRUCELLI
&&
.AVIATION...FOR THE 03/12Z TAF CYCLE...CONDITIONS WILL BE VFR
THROUGH THIS EVENING THEN ONSHORE FLOW WILL BRING MAINLY VFR CIGS
BUT LOCAL MVFR CIGS WITH MOUNTAIN OBSCURATION INTO SOUTHWEST OREGON
LATE TONIGHT INTO FRIDAY MORNING. /DW
&&
.MARINE...UPDATED 500 AM PDT THURSDAY 3 SEPTEMBER 2015...SMALL CRAFT
ADVISORY LEVEL NORTH WINDS AT THE LOW END OF CRITERIA WILL DEVELOP
SOUTH OF GOLD BEACH BEYOND 5 NM FROM SHORE LATE THIS MORNING. THESE
WINDS WILL REACH A PEAK IN THE EARLY EVENING THEN DIMINISH OVERNIGHT
BEFORE RETURNING TO ABOUT THE SAME STRENGTH FOR LATE FRIDAY MORNING
THROUGH FRIDAY EVENING. AFTER ANOTHER DECREASE IN WINDS LATE FRIDAY
NIGHT, WINDS WILL BECOME STRONGER DURING THE WEEKEND. WINDS WILL
STILL BE MODERATE SATURDAY BUT GALES ARE POSSIBLE IN THE SOUTHERN
OUTER WATERS WITH SMALL CRAFT WINDS ELSEWHERE SUNDAY INTO MONDAY.
WINDS ARE EXPECTED TO RETURN TO MODERATE STRENGTH BEYOND
MONDAY. /DW
&&
.PREV DISCUSSION... /ISSUED 351 AM PDT THU SEP 3 2015/
DISCUSSION...A COLD FRONT THAT MOVED THROUGH LATE WEDNESDAY HAS
LEFT MOST OF THE AREA 5 TO 10 DEGREES COOLER VERSUS THIS TIME VERSUS
YESTERDAY. EVENING SHIFT PUT UP A FROST ADVISORY FOR SOME OF THE
EAST SIDE. THE DAY SHIFT TODAY WILL NEED TO CONSIDER THE SAME FOR
TONIGHT AND FRIDAY NIGHT AS THE CENTER OF AN UNUSUALLY COLD UPPER
LOW DIVES IN OVERHEAD. THIS LOW WILL BRING THE COOLEST AIR OF THE
SEASON WITH A COLD CORE OF -25C AT 500 MILLIBARS. AS THE TROUGH
SWINGS EASTWARD AND SKIES CLEAR SATURDAY NIGHT INTO SUNDAY...
THERE WILL BE A THREAT FOR FREEZING MORNING TEMPERATURES ACROSS
MUCH OF THE LOWLANDS EAST OF THE CASCADES. A SPECIAL WEATHER
STATEMENT WILL COVER THIS UPCOMING POTENTIAL FOR FROST AND FREEZE
FOR AGRICULTURAL INTERESTS.
RAIN WITH THIS SYSTEM TODAY SHOULD REMAIN FAIRLY SLIM. THE 88D IS
CURRENTLY SHOWING SOME WEAK ECHOES STREAMING SOUTHWEST TO
NORTHEAST BETWEEN KLAMATH FALLS AND LAKEVIEW IN REGION OF COLDER
CLOUD TOPS BETWEEN -10 TO -15C IN THICKER CLOUD. PER THE RUC AND
HRRR FORECASTS, WE DID BUMP UP PROBABILITIES A BIT FOR A HUNDREDTH
OR TWO OUR THERE AROUND SOUTHERN LAKE COUNTY WITH SHORT WAVE
ENERGY OVERRIDING THE SLOWLY PROGRESSING FRONTAL ZONE. THIS SHOULD
TAPER OFF THIS EVENING WITH A FAIRLY UNEVENTFUL NIGHT IN STORE.
ACTIVITY WILL INCREASE FRIDAY WITH THE APPROACH OF THE DEEP UPPER
LOW FROM THE NORTH. FAIRLY STRONG SHORT WAVE ENERGY IS FORECAST TO
DIG THROUGH THE BASE OF THE TROUGH OVER SOUTHERN OREGON AND NORTHERN
CALIFORNIA FRIDAY AFTERNOON AND EVENING. WITH THE COLD AIR ALOFT,
NUMEROUS SHOWERS AND A SLIGHT CHANCE FOR THUNDERSTORMS WITH SOME
LOCALIZED MODERATE RAINS ARE IN STORE. THE BEST SHOT AT GOOD RAIN
WILL BE EAST OF THE CASCADES. DUE TO BUILDING CONFIDENCE BASED ON
SUPPORT FROM RECENT MODEL RUNS, HAVE ALSO BUMPED UP POPS A BIT
MORE IN THIS TIME FRAME.
SHOWERS WILL BE LINGERING INTO SATURDAY MORNING MAINLY FROM THE
CASCADES EAST. SNOW LEVELS EARLY SATURDAY SHOULD BOTTOM OUT BETWEEN
6000 AND 6500 FEET OVER THE CASCADES, AND MORE LIKE 7KFT IN
NORTHERN CALIFORNIA. SO, A LITTLE DUSTING ON THE HIGHER TERRAIN
LOOKS LIKELY. SOME UNCERTAINTY EXISTS FOR AREAS IN LAKE COUNTY
WHERE THE MORE SIGNIFICANT PRECIP WILL FALL. THE WARNERS INCLUDING
HART MTN AREA ABOVE 6500 FEET SHOULD BE AWARE OF THE POTENTIAL FOR
A LITTLE MORE SNOW THERE.
AS THE SYSTEM CLEARS OUT SATURDAY AFTERNOON AND NIGHT, THIS WILL
LEAVE SUNDAY MORNING WITH A FAIR POTENTIAL TO FREEZE IN MANY AREAS
OF WHAT LOOKS LIKE MAINLY LAKE AND MODOC COUNTIES. A WARMING TREND
LOOKS LIKELY THEREAFTER THROUGH LATE WEEK. STAVISH
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR
PZZ356-376.
SMALL CRAFT ADVISORY FROM 11 AM TO 11 PM PDT FRIDAY FOR PZZ376.
$$
AREA FORECAST DISCUSSION
NWS MEDFORD OR
351 AM PDT THU SEP 3 2015
.DISCUSSION...A COLD FRONT THAT MOVED THROUGH LATE WEDNESDAY HAS
LEFT MOST OF THE AREA 5 TO 10 DEGREES COOLER VERSUS THIS TIME VERSUS
YESTERDAY. EVENING SHIFT PUT UP A FROST ADVISORY FOR SOME OF THE
EAST SIDE. THE DAY SHIFT TODAY WILL NEED TO CONSIDER THE SAME FOR
TONIGHT AND FRIDAY NIGHT AS THE CENTER OF AN UNUSUALLY COLD UPPER
LOW DIVES IN OVERHEAD. THIS LOW WILL BRING THE COOLEST AIR OF THE
SEASON WITH A COLD CORE OF -25C AT 500 MILLIBARS. AS THE TROUGH
SWINGS EASTWARD AND SKIES CLEAR SATURDAY NIGHT INTO SUNDAY...
THERE WILL BE A THREAT FOR FREEZING MORNING TEMPERATURES ACROSS
MUCH OF THE LOWLANDS EAST OF THE CASCADES. A SPECIAL WEATHER
STATEMENT WILL COVER THIS UPCOMING POTENTIAL FOR FROST AND FREEZE
FOR AGRICULTURAL INTERESTS.
RAIN WITH THIS SYSTEM TODAY SHOULD REMAIN FAIRLY SLIM. THE 88D IS
CURRENTLY SHOWING SOME WEAK ECHOES STREAMING SOUTHWEST TO
NORTHEAST BETWEEN KLAMATH FALLS AND LAKEVIEW IN REGION OF COLDER
CLOUD TOPS BETWEEN -10 TO -15C IN THICKER CLOUD. PER THE RUC AND
HRRR FORECASTS, WE DID BUMP UP PROBABILITIES A BIT FOR A HUNDREDTH
OR TWO OUR THERE AROUND SOUTHERN LAKE COUNTY WITH SHORT WAVE
ENERGY OVERRIDING THE SLOWLY PROGRESSING FRONTAL ZONE. THIS SHOULD
TAPER OFF THIS EVENING WITH A FAIRLY UNEVENTFUL NIGHT IN STORE.
ACTIVITY WILL INCREASE FRIDAY WITH THE APPROACH OF THE DEEP UPPER
LOW FROM THE NORTH. FAIRLY STRONG SHORT WAVE ENERGY IS FORECAST TO
DIG THROUGH THE BASE OF THE TROUGH OVER SOUTHERN OREGON AND NORTHERN
CALIFORNIA FRIDAY AFTERNOON AND EVENING. WITH THE COLD AIR ALOFT,
NUMEROUS SHOWERS AND A SLIGHT CHANCE FOR THUNDERSTORMS WITH SOME
LOCALIZED MODERATE RAINS ARE IN STORE. THE BEST SHOT AT GOOD RAIN
WILL BE EAST OF THE CASCADES. DUE TO BUILDING CONFIDENCE BASED ON
SUPPORT FROM RECENT MODEL RUNS, HAVE ALSO BUMPED UP POPS A BIT
MORE IN THIS TIME FRAME.
SHOWERS WILL BE LINGERING INTO SATURDAY MORNING MAINLY FROM THE
CASCADES EAST. SNOW LEVELS EARLY SATURDAY SHOULD BOTTOM OUT BETWEEN
6000 AND 6500 FEET OVER THE CASCADES, AND MORE LIKE 7KFT IN
NORTHERN CALIFORNIA. SO, A LITTLE DUSTING ON THE HIGHER TERRAIN
LOOKS LIKELY. SOME UNCERTAINTY EXISTS FOR AREAS IN LAKE COUNTY
WHERE THE MORE SIGNIFICANT PRECIP WILL FALL. THE WARNERS INCLUDING
HART MTN AREA ABOVE 6500 FEET SHOULD BE AWARE OF THE POTENTIAL FOR
A LITTLE MORE SNOW THERE.
AS THE SYSTEM CLEARS OUT SATURDAY AFTERNOON AND NIGHT, THIS WILL
LEAVE SUNDAY MORNING WITH A FAIR POTENTIAL TO FREEZE IN MANY AREAS
OF WHAT LOOKS LIKE MAINLY LAKE AND MODOC COUNTIES. A WARMING TREND
LOOKS LIKELY THEREAFTER THROUGH LATE WEEK. STAVISH
&&
.AVIATION...FOR THE 03/06Z TAF CYCLE...ALONG THE COAST EXPECT
MAINLY VFR CONDITIONS WITH ISOLATED MVFR/ CIGS THROUGH EARLY THIS
MORNING...BECOMING VFR BY 18Z. INLAND, FOR AREAS WEST OF THE
CASCADES, CONDITIONS WILL BE MAINLY VFR BUT ONSHORE FLOW WILL
MAINTAIN SOME MID CLOUDS ALONG AND JUST WEST OF THE CASCADES LATE
TONIGHT AND EARLY THIS MORNING. THIS WILL BRING AREAS OF MOUNTAIN
OBSCURATION NEAR THE CASCADES. ALSO AREAS OF MVFR CIGS ARE
EXPECTED TO DEVELOP IN THE UMPQUA BASIN LATE TONIGHT INTO EARLY
THIS MORNING...WITH CLEARING AROUND 17Z. EAST OF THE CASCADES,
EXPECT SOME LIGHT SHOWERS AND AREAS OF MOUNTAIN OBSCURATIONS
THROUGH THE MORNING AS A FRONT SHIFTS EASTWARD OVER THE
AREA...WITH VFR IN THE AFTERNOON AND EVENING. /CC
&&
.MARINE...UPDATED 1030 PM PDT WEDNESDAY 2 SEPTEMBER 2015...A TROUGH
OF LOW PRESSURE WILL MOVE THROUGH THE WATERS TONIGHT THROUGH FRIDAY
WITH PERIODS OF SHOWERS POSSIBLE. IN ADDITION, THIS SYSTEM WILL
BRING A SLIGHT CHANCE OF THUNDERSTORMS OVER THE WATERS FRIDAY
MORNING. WINDS WILL INCREASE TONIGHT THROUGH THURSDAY...WITH SEAS
BECOMING A MIX OF SWELL AND SHORT PERIOD WIND WAVE BY THURSDAY
EVENING. SOME SMALLER LONGER PERIOD SWELLS WILL BE MIXED IN. THE
COASTAL WATERS WILL BE DOMINATED BY MODERATE TO STRONG NORTH WINDS
THURSDAY THROUGH THE WEEKEND...WITH SMALL CRAFT ADVISORY CONDITIONS
SOUTH OF CAPE BLANCO. THERE IS ENOUGH SUPPORT FROM MODELS TO BRING
SMALL CRAFT ADVISORY CONDITIONS INTO THE INNER WATERS SOUTH OF GOLD
BEACH THURSDAY AFTERNOON AND EVENING. MODERATE NORTH WINDS CONTINUE
FRIDAY INTO SATURDAY. THEN WINDS ARE FORECAST TO STRENGTHEN SUNDAY
INTO MONDAY WITH GALES POSSIBLE IN THE SOUTHERN OUTER WATERS. STRONG
NORTHERLY WINDS ARE LIKELY TO PERSIST THROUGH EARLY NEXT WEEK.
SK/CC
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...FROST ADVISORY UNTIL 8 AM PDT THIS MORNING FOR ORZ029>031.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING
TO 11 AM PDT FRIDAY FOR PZZ376.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 11 PM THIS EVENING
TO 11 AM PDT FRIDAY FOR PZZ376.
SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 11 PM PDT THIS
EVENING FOR PZZ356.
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1009 AM CDT THU SEP 3 2015
.DISCUSSION...
SKIES ARE MOSTLY SUNNY ACROSS THE FORECAST AREA THIS MORNING WITH
TEMPERATURES MAINLY IN THE LOW TO MID 80S. LATEST HRRR MODEL STILL
SHOWS SOME THUNDERSTORM DEVELOPMENT IS POSSIBLE THIS AFTERNOON
OVER EASTERN SECTIONS OF THE FORECAST AREA. WILL UPDATE FORECAST
TO REMOVE MORNING WORDING WITH NO BIG CHANGES NEEDED.
ARS
&&
.PREV DISCUSSION... /ISSUED 618 AM CDT THU SEP 3 2015/
DISCUSSION...
AN UPPER LEVEL SHEAR AXIS THAT HAS PERSISTED ACROSS THE MID SOUTH
OVER THE PAST FEW DAYS HAS SHIFTED EAST THIS MORNING AND NOW
RESIDES ACROSS THE EASTERN HALF OF THE FORECAST AREA. DAYTIME
HEATING AND WEAK LIFT ASSOCIATED WITH THIS UPPER TROUGH WILL LEAD
TO MORE ISOLATED SHOWERS AND THUNDERSTORMS THIS AFTERNOON ACROSS
WEST TENNESSEE...NEAR THE TENNESSEE RIVER...AND NORTHEAST
MISSISSIPPI. ELSEWHERE...UPPER LEVEL RIDGING WILL BUILD FROM THE
WEST WITH DRIER MID LEVEL AIR AND SUBSIDENCE WHICH SHOULD
SUPPRESS MOST CONVECTION. HOT AND HUMID CONDITIONS WILL CONTINUE
WITH MOST LOCATIONS REACHING INTO THE LOWER TO MIDDLE 90S THIS
AFTERNOON WITH DEWPOINTS NEAR 70 DEGREES. HEAT INDEX VALUES WILL
RISE INTO THE LOWER 100S IN MANY AREAS MAKING CONDITIONS FEEL
UNCOMFORTABLY HOT FOR THIS TIME OF YEAR.
UPPER LEVEL RIDGING SHOULD BUILD EAST OVER THE ENTIRE MID SOUTH
FOR FRIDAY AND CONTINUE TO CONTROL THE WEATHER CONDITIONS THROUGH
THE WEEKEND INTO EARLY NEXT WEEK. PRIMARILY DRY WEATHER ALONG WITH
A CONTINUATION OF HOT AND HUMID CONDITIONS SHOULD CONTINUE
THROUGH NEXT MONDAY. HIGH TEMPERATURES SHOULD REMAIN IN THE LOWER
TO MIDDLE 90S WITH LOWS IN THE UPPER 60S TO MIDDLE 70S. HEAT INDEX
VALUES SHOULD CONTINUE TO EXCEED 100 DEGREES EACH AFTERNOON IN
MANY LOCATIONS.
THE UPPER RIDGE SHOULD BREAK DOWN BY NEXT TUESDAY ALLOWING A SERIES
OF UPPER LEVEL SHORTWAVE DISTURBANCES TO PASS ACROSS THE REGION
THROUGH THE MIDDLE OF NEXT WEEK. A COLD FRONT SHOULD ALSO MOVE
SOUTH AND STALL ACROSS THE REGION BY THE END OF THE EXTENDED
FORECAST PERIOD. THERE REMAINS PLENTY OF MODEL DIFFERENCES THROUGH
THIS TIME PERIOD...SO TOOK A MODEL BLEND AND INCREASED CHANCES FOR
SHOWERS AND THUNDERSTORMS. TEMPERATURES SHOULD DROP BACK TO NEAR
NORMAL VALUES BUT WITH CONTINUED HUMID CONDITIONS.
JLH
&&
.AVIATION...
12Z TAF SET
VFR WEATHER WILL PREVAIL THIS PERIOD WITH PATCHY FOG REDEVELOPING
AT MKL AND TUP LATE. AN ISOLATED SHOWER NEAR TUP IS ALSO POSSIBLE
THROUGHOUT THE AFTERNOON. CALM OR LIGHT WINDS THROUGH THE PERIOD.
JAB
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1002 AM CDT THU SEP 3 2015
.UPDATE...NO SIGNIFICANT UPDATES THIS MORNING WITH TODAYS FORECAST
ON TRACK WEATHER AND TEMPERATURE WISE. ONE SMALL ADJUSTMENT MADE
WAS SLIGHTLY REDUCING THE 30% POP IN LAVACA AND FAYETTE COUNTIES
TO 20% AND SHIFTING THE 30% AREA INTO KARNES COUNTY THROUGH 1PM.
THIS SHIFTING WAS DUE TO ONGOING RADAR TRENDS. HOURLY DEWPOINTS
WERE ALSO INCREASED ACROSS EASTERN LOCATIONS TO BETTER MATCH
OBSERVATIONS. UPDATES ARE OUT AND MORE DETAILS CAN BE FOUND BELOW
IN THE UPDATED DISCUSSION.
&&
.DISCUSSION... SOME SHOWERS ARE ONGOING ALONG THE COAST AND EXTEND
INLAND INTO DEWITT AND KARNES COUNTY THIS MORNING. ADDITIONAL
ISOLATED TO SCATTERED SHOWERS WILL BE LIKELY THROUGH THE AFTERNOON
PRIMARILY EAST OF THE I-35/37 CORRIDOR WHERE THE SEA-BREEZE
ACTIVITY WILL BE MORE PRONOUNCED. WATER VAPOR AND MID TO UPPER
LEVEL RAP ANALYSIS DEPICTS A CLOSED CUT-OFF LOW OVER THE GULF OF
MEXICO SE OF THE TEXAS COAST. THIS FEATURE MAY BE JUST DISTANT
ENOUGH NOT TO HAVE TO MUCH BEARING ON OUR WEATHER TODAY OTHER THAN
DEEPER LEVEL STEERING FLOW FROM THE EAST. THIS FLOW MAY HELP SOME
SEA-BREEZE ACTIVITY PUSH FROM THE EAST TO WEST TOWARDS THE 35
CORRIDOR THIS AFTERNOON AND EARLY EVENING. HOWEVER...OVERALL
CHANCES REMAIN LOW WITH 20-30%. LOW 800-500MB LAPSE RATES AND A
WARM NOSE NEAR 500MB WILL HAMPER DEEPER DEVELOPMENT OF THE
CONVECTION AND THUNDERSTORMS MAY BE HARD TO COME BY IN THIS
ENVIRONMENT. AN UPDATE DURING THE AFTN MAY REMOVE THE CURRENT
THUNDER WORDING AND BE REPLACED WITH GENERAL SHOWERS INSTEAD.
&&
.PREV DISCUSSION... /ISSUED 650 AM CDT THU SEP 3 2015/
AVIATION...
STRATUS CLOUDS CONTINUE TO DEVELOP THIS MORNING...WITH MVFR CIGS
ALREADY IN PLACE ACROSS MOST AREAS. STILL THINK THERE IS SOME
OPPORTUNITY FOR IFR CIGS FOR THE NEXT FEW HOURS AND WILL MENTION
TEMPO GROUPS ALONG THE I-35 CORRIDOR THROUGH 15Z. IMPROVING
CONDITIONS ARE IN STORE AFTER 16Z-17Z WITH VFR CONDITIONS
RETURNING TO ALL TERMINALS. ISOLATED CONVECTION IS STILL POSSIBLE
TODAY...BUT GIVEN LACK OF COVERAGE...WILL NOT MENTION IN THE
FORECAST AT THIS TIME. LOW CLOUDS WILL DEVELOP AFTER LATE TONIGHT
INTO FRIDAY MORNING...WITH MVFR CIGS EXPECTED AFTER 04/08Z. WINDS
WILL GENERALLY REMAIN FROM THE EAST AND SOUTHEAST AT OR BELOW
10KTS THROUGH THE PERIOD.
PREV DISCUSSION... /ISSUED 419 AM CDT THU SEP 3 2015/
SHORT TERM (TODAY THROUGH FRIDAY)...
WV IMAGERY AND UPPER AIR ANALYSES SHOW THAT THE WEAK SHEAR AXIS
AND ASSOCIATED TROUGH THAT STRETCHES FROM THE LOWER MISSISSIPPI
RIVER VALLEY TO THE SE TX AND LA GULF COAST CONTINUES TO WEAKEN.
ISOLATED SHOWERS AND THUNDERSTORMS ARE FORMING OVER THE GULF AND
MOVING ONSHORE...BUT THE COVERAGE IS LOWER THAN THE LAST FEW
NIGHTS. MOST OF THESE SHOWERS WILL DISSIPATE...BUT A ROGUE
SHOWER OR TWO MAY MOVE INTO OUR SE COUNTIES TOWARDS DAYBREAK. LOW
STRATUS HAS BEEN SLOWER TO DEVELOP TONIGHT THAN THE PREVIOUS FEW
EVENINGS...BUT STILL EXPECT THEM TO MOVE IN WITHIN THE NEXT FEW
HOURS AND PERSIST FOR A FEW HOURS AFTER SUNRISE TODAY AND FRIDAY.
MODELS ARE CONSISTENT IN BUILDING AND INTENSIFYING THE UPPER
LEVEL RIDGE OVER THE SOUTHERN PLAINS TODAY AND FRIDAY AS AN
INVERTED TROUGH BREAKS OFF FROM THE PROGRESSIVE TROUGH AND
RETROGRADES UNDER THE RIDGE AS IT WEAKENS. THIS WILL HELP CAUSE A
0.2-0.3 INCH SURGE IN PWAT VALUES AND SLIGHTLY DEEPER CONVERGENCE
WITH THE SEA BREEZE THAN OCCURRED ON WEDNESDAY...ALLOWING FOR
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS IN THE COASTAL
PLAINS THAT WILL DISSIPATE AS THEY MOVE INTO THE I-35 CORRIDOR.
MODELS HAVE GENERALLY BACKED OFF FROM SHOWERS MOVING INTO THE HILL
COUNTRY EXCEPT FOR THE ECMWF AND A FEW HI-RES MODELS FOR FRIDAY.
LONG TERM (FRIDAY NIGHT THROUGH WEDNESDAY)...
THE UPPER LEVEL RIDGE WILL CONTINUE TO INTENSIFY THROUGH THE
WEEKEND AS THE RETROGRADING SHEAR AXIS DISSIPATES. THIS WILL LEAD
TO HOT AND GENERALLY DRY DAYS ASIDE FROM ISOLATED AFTERNOON
SHOWERS AND THUNDERSTORMS IN THE COASTAL PLAINS ON SATURDAY. HEAT
INDEX VALUES WILL RISE INTO THE 100-105 RANGE EVERYWHERE EXCEPT
THE COUNTRY FOR ALL OF LABOR DAY WEEKEND...WITH HIGH TEMPS IN THE
MID-TO-UPPER 90S EXCEPT FOR A FEW SPOTS IN THE RIO GRANDE PLAINS
THAT REACH THE CENTURY MARK. THE RIDGE GRADUALLY BEGINS TO WEAKEN
AND SLIDE TO THE WEST BY WEDNESDAY...WHICH MAY ALLOW A WEAK FRONT
TO MOVE INTO THE REGION LATE THURSDAY INTO FRIDAY JUST PAST THE
FORECAST PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 93 73 95 75 97 / 20 20 20 10 10
AUSTIN BERGSTROM INTL AIRPORT 92 72 94 73 96 / 20 20 20 10 10
NEW BRAUNFELS MUNI AIRPORT 93 73 96 74 97 / 20 20 20 10 10
BURNET MUNI AIRPORT 92 73 94 73 95 / 10 10 10 10 10
DEL RIO INTL AIRPORT 97 75 97 76 98 / 10 10 10 10 10
GEORGETOWN MUNI AIRPORT 92 73 94 75 95 / 10 10 10 10 10
HONDO MUNI AIRPORT 95 73 96 74 97 / 10 10 10 10 10
SAN MARCOS MUNI AIRPORT 92 73 94 75 96 / 20 20 20 10 10
LA GRANGE - FAYETTE REGIONAL 92 73 94 75 95 / 30 30 20 10 20
SAN ANTONIO INTL AIRPORT 94 74 95 76 96 / 20 20 10 10 10
STINSON MUNI AIRPORT 95 74 96 76 97 / 20 20 10 10 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...05
SYNOPTIC/GRIDS...ALLEN
PUBLIC SERVICE/DATA COLLECTION...30
AREA FORECAST DISCUSSION...CORRECTED SHORT TERM
NWS CHEYENNE WY
535 AM MDT THU SEP 3 2015
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 300 AM MDT THU SEP 3 2015
PRETTY QUIET WEATHER EARLY THIS MORNING ACROSS THE FORECAST AREA.
CURRENT WATER VAPOR LOOP SHOWS A RIDGE AXIS BUILDING OVER THE
GREAT PLAINS AS A BROAD UPPER LEVEL TROUGH SETTLES OVER THE
PACIFIC NORTHWEST...BRINGING MUCH NEEDED RAINFALL TO WASHINGTON
AND OREGON. THIS SYSTEM WILL EVENTUALLY IMPACT WYOMING THIS
WEEKEND. BEFORE THIS...CURRENT WATER VAPOR ALSO SHOWS A WELL
DEFINED SHORTWAVE DISTURBANCE ALOFT NEAR THE FOUR CORNERS REGION
WITH MID TO HIGH CLOUDS MOVING NORTHWARD WELL AHEAD OF IT. THIS
FEATURE WILL BE THE MAIN FORECAST CONCERN TODAY. A FEW MODELS
SHOW THIS FEATURE MOVING OVER SOUTHEAST WYOMING THIS AFTERNOON
PRODUCING SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS.
THUNDERSTORMS MAY PRODUCE SOME HEAVY RAINFALL AS SHORT RANGE
MODELS SUCH AS THE HRRR INDICATE REDEVELOPMENT AND TRAINING OVER
THE SAME AREA INTO LATE THIS EVENING. THIS IS DUE TO A POTENT
UPPER LEVEL JET AND GOOD 300MB DIFLUENCE ALOFT. HOWEVER...NOT ALL
MODELS AGREE ON THE TIMING OF THIS FEATURE...WITH THE ECMWF AND
GEM 3 TO 6 HOURS BEHIND THE GFS. DUE TO PEAK HEATING AND AVAILABLE
INSTABILITY...THIS TIMING DIFFERENCE IS SIGNIFICANT. THE NEW 06Z
NAM IS IN GOOD AGREEMENT WITH THE GFS AND HRRR...SO CONFIDENCE IS
INCREASING THAT SEVERAL BANDS OF SHOWERS AND TSTORMS WILL DEVELOP
OVER THE ROCKY MOUNTAINS AND QUICKLY LIFT NORTHEAST ACROSS THE I25
AND I80 CORRIDORS BY THIS AFTERNOON. INCREASED POP ACROSS MOST OF
THE AREA WITH THE EXCEPTION OF CARBON COUNTY. INCREASED POP
BETWEEN 30 TO 60 PERCENT FURTHER SOUTH AND WEST...SINCE THERE IS
STILL LOW CONFIDENCE IN SHOWER/TSTORM COVERAGE NORTH OF THE PLATTE
RIVER VALLEY DUE TO TIMING DIFFERENCES.
FRIDAY WILL BE PRETTY SIMILAR TO THURSDAY WITH HIGH TEMPERATURES
IN THE 80S TO MID 90S AND ANOTHER GOOD CHANCE OF AFTERNOON SHOWERS
AND TSTORMS. IN FACT...CONDITIONS APPEAR MORE FAVORABLE IN THE
EVENING AS THE NAM...GFS...AND ECMWF SHOW QUITE A BIT OF UPPER
LEVEL DIFLUENCE DUE TO JET DYNAMICS ALOFT. THIS DYNAMIC LIFT PEAKS
BETWEEN 00Z TO 06Z FRIDAY EVENING BEFORE LIFTING NORTHEAST.
INCREASED POP UP TO 45 PERCENT ACROSS THE HIGH PLAINS FRIDAY
EVENING.
THE UPPER LEVEL TROUGH OVER THE PACIFIC NORTHWEST WILL MOVE
TOWARDS THE FORECAST AREA ON SATURDAY. IT WILL BE SLIGHTLY COOLER
WITH HIGHS IN THE UPPER 70S TO UPPER 80S...BUT THE PRIMARY COLD
FRONT WILL NOT ENTER SOUTHEAST WYOMING UNTIL LATE SATURDAY NIGHT.
THIS MAIN STORM SYSTEM IS EXPECTED TO MOVE NORTHEAST AND REMAIN
NORTH OF THE FORECAST AREA. KEPT POP BETWEEN 10 TO 20 PERCENT WITH
THE HIGHEST CHANCE ACROSS THE MOUNTAINS...DUE TO SOME DRIER AIR
ALOFT AND A STABLE LAYER AROUND 500MB WHICH WILL INHIBIT WIDESPREAD
CONVECTION.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 230 AM MDT THU SEP 3 2015
THE UPPER LEVEL TROUGH WILL SWING NORTHEASTWARD ACROSS NORTHERN WY
ON SAT NIGHT AND SUN MORNING WITH AN ASSOCIATED FROPA. WINDS WILL
REALLY INCREASE BEHIND THE FRONT ON SUN MORNING AS THE MODELS SHOW
700MB WINDS OF 35-40 KTS OVER SOUTHEAST WY. THE GRADIENT DOES BEGIN
TO RELAX BY THE AFTN SO WINDS WILL COME DOWN SOME. WITH A VERY DRY
AIR MASS IN PLACE ON SUN AND MIN RH VALUES FALLING TO AROUND 15
PERCENT...THERE WILL LIKELY BE SOME FIRE WEATHER CONCERNS DESPITE
THE COOLER TEMPS. DRY WESTERLY MID LEVEL FLOW WILL REMAIN IN PLACE
THROUGH EARLY NEXT WEEK WITH PW VALUES OF ONLY 0.25-0.5 INCHES AND
NO HINT OF ANY MONSOONAL MOISTURE INTRUSION. TEMPS WILL BE AROUND
NORMAL FOR EARLY SEP WITH COOLER NIGHTS THAN WE HAVE SEEN RECENTLY.
THE MODEL DIFFERENCES BETWEEN THE GFS AND ECMWF REALLY BEGIN TO SHOW
UP BY TUESDAY AS THE GFS SHOWS A STRONGER SHORTWAVE MOVING ACROSS WY.
REGARDLESS OF THE SOLUTION...A DRY FCST WILL PREVAIL WITH LIMITED
MOISTURE AND DYNAMICS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 532 AM MDT THU SEP 3 2015
VFR CONDITIONS THROUGH THE TAF PERIOD. WINDS WILL MOSTLY REMAIN
BELOW 15 KTS...EXCEPT AT RWL WHERE GUSTS TO 20 KTS WILL BE
POSSIBLE DURING THE AFTERNOON. ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS WILL DEVELOP AFTER 20Z ACROSS SOUTHEAST WY AND THEN
MOVE EASTWARD INTO THE NEBRASKA PANHANDLE THROUGH THE EVENING.
GUSTY AND ERRATIC WINDS ALONG WITH BRIEF HEAVY RAIN WILL BE
POSSIBLE WITH THE STORMS.
&&
.FIRE WEATHER...
ISSUED AT 230 AM MDT THU SEP 3 2015
IT WILL BE PRETTY DRY INITIALLY THIS AFTERNOON OVER EAST CENTRAL
WYOMING BEFORE SOME SUBTROPICAL MOISTURE MOVES INTO THE
AREA...AHEAD OF AN UPPER LEVEL DISTURBANCE. ALTHOUGH FIRE WEATHER
CONCERNS ARE LOW TODAY...WILL HAVE TO MONITOR WIND SPEEDS ACROSS
ZONE 301 AND 302. FOR NOW...WINDS ARE EXPECTED TO BE BELOW 20 MPH
AT THIS TIME. MINIMAL FIRE WEATHER CONCERNS ARE ANTICIPATED FRIDAY
AND SATURDAY AS THUNDERSTORM COVERAGE WILL INCREASE AND RELATIVE
HUMIDITIES WILL TREND HIGHER...MINIMUM DAYTIME RELATIVE HUMIDITIES
WILL BE BETWEEN 20 TO 30 PERCENT BY SATURDAY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...TJT
LONG TERM...ZF
AVIATION...ZF
FIRE WEATHER...TJT
AREA FORECAST DISCUSSION
NWS FLAGSTAFF AZ
352 PM MST THU SEP 3 2015
.SYNOPSIS...SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE OVER
THE NEXT SEVERAL DAYS...WITH THE BEST CHANCES OF STORMS OVER THE
EASTERN HALF OF THE STATE. DRIER CONDITIONS MAY RETURN TO NORTHERN
ARIZONA EARLY NEXT WEEK.
&&
.DISCUSSION...SO FAR TODAY, SHOWER AND THUNDERSTORM ACTIVITY HAS
GENERALLY BEEN CONFINED TO PORTIONS OF NORTHERN GILA, AND
SOUTHERN NAVAJO AND APACHE COUNTIES. THE PRIMARY HAZARD FROM THESE
STORMS HAS BEEN LOCALIZED FLOODING FROM HEAVY RAINFALL.
FOR THE REST OF TODAY AND TONIGHT...SHOWER AND THUNDERSTORM
ACTIVITY IS EXPECTED TO CONTINUE PRIMARILY ALONG AND TO THE NORTH
OF THE EASTERN MOGOLLON RIM AND WHITE MOUNTAINS THIS AFTERNOON.
HI-RES MODEL GUIDANCE STILL INDICATES THAT OUTFLOWS FROM
CONVECTIVE ACTIVITY OVER SOUTHERN ARIZONA MAY TRIGGER NEW SHOWERS
AND THUNDERSTORMS ALONG AND SOUTH OF THE MOGOLLON RIM FROM
FLAGSTAFF EASTWARD - ALTHOUGH THE HRRR HAS BACKED OFF ON THIS
PREDICTION OVER THE LAST COUPLE OF RUNS.
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS IS EXPECTED ON FRIDAY,
WITH THE GREATEST ACTIVITY ROUGHLY EAST OF LINE FROM
PRESCOTT-FLAGSTAFF-PAGE. LOCALIZED FLOODING FROM HEAVY RAINFALL
WILL CONTINUE TO BE THE PRIMARY HAZARD, BUT INCREASING DEEP LAYER
SHEAR MEANS LARGE HAIL CANNOT BE RULED OUT.
SATURDAY ONWARD...AS WE ENTER THE WEEKEND...FLOW WILL TURN WEST-
SOUTHWESTERLY AS LOW PRESSURE SHIFTS ACROSS THE GREAT BASIN. THIS
SHOULD LEAD TO A DOWNTURN IN ACTIVITY FROM LATE SATURDAY INTO
EARLY NEXT WEEK. ECMWF KEEPS MOISTURE MUCH MORE LIMITED THROUGH
THE EXTENDED FORECAST WHILE THE GFS IS MORE FAVORABLE TO RETURNING
STORM CHANCES NEXT WEEK. WILL CONTINUE TO OBSERVE MODEL FORECAST
TRENDS OVER THE COMING DAYS.
&&
.AVIATION...FOR THE 00Z PACKAGE...SCATTERED STORMS WILL CONTINUE
THIS EVENING ACROSS NAVAJO, APACHE, AND GILA COUNTIES. ANOTHER ROUND
OF SCATTERED SHRA/TSRA WILL DEVELOP AFT 18Z FRIDAY PRIMARILY ALONG
AND EAST OF A PRESCOTT-FLAGSTAFF-PAGE LINE. ISOLATED STORMS
POSSIBLE ELSEWHERE. LOCALIZED IFR CONDITIONS POSSIBLE IN MOD/HVY
RAIN ALONG WITH GUSTY STORM OUTFLOWS TO 30 KTS. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...RR
AVIATION...CLM
FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT
WEATHER.GOV/FLAGSTAFF
AREA FORECAST DISCUSSION
NWS NEW YORK NY
331 PM EDT THU SEP 3 2015
.SYNOPSIS...
A COLD FRONT PASSES THROUGH TONIGHT FROM THE NORTH. HIGH PRESSURE
BUILDS DOWN FROM SOUTHEASTERN CANADA ON FRIDAY AND REMAINS IN
CONTROL THROUGH THE MIDDLE OF NEXT WEEK...WITH A COLD FRONT
POSSIBLY APPROACHING LATE IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS OF 19Z...CONVECTION IS WELL NORTH AND WEST OVER THE MOUNTAINS.
PER LATEST HRRR AND RAP RUNS ALONG WITH NARRE-TL DISSIPATION OF
CONVECTION IS FORECAST WITH LOSS OF DAYTIME HEATING. ONLY AREA
THAT COULD GET A STORM THOUGH 8 PM IS ORANGE COUNTY WHERE MUCAPE`S
ARE NEAR 1500 J/KG.
HAVE LIMITED POPS TO ISOLATED OVERNIGHT BASED ON NWP, LIMITED
DYNAMICS (WEAK PVA) AND MODEST AT BEST INSTABILITY.
LOWS ARE A MOS BLEND IN THE MID 60S TO LOWER 70S IN THE NY METRO.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
BIG CHANGE IN THE WEATHER FOR FRI AS NE WIND USHERS IN COOLER AND
DRIER AIR. ALSO EXTENSIVE COULD COVER IS FORECAST. TEMPS COULD
ACTUALLY NOT BREAK 80 IN CENTRAL PARK FOR THE FIRST TIME IN NEARLY
2 MONTHS. HAVE GONE WITH COOLER GFS MOS BASED ON EXPECTATIONS OF
EXTENSIVE CLOUD COVER. MAX TEMPS ARE NEAR 80.
CLEARING FOR FRIDAY NIGHT WITH THE NE FLOW PERSISTING.
RIP CURRENT POTENTIAL INCREASE THROUGH THE DAY AS SEAS BUILD AND
LONG SHORE CURRENT INCREASES ALONG THE SOUTH SHORE OF LONG ISLAND.
HIGH RISK LIKELY PERSISTS INTO SATURDAY.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
GRADUALLY INCREASING DROUGHT AND FIRE WEATHER CONCERNS THROUGH THE
PERIOD.
MODELS IN GOOD AGREEMENT WITH UPPER RIDGING OVER THE REGION THIS
WEEKEND...GRADUALLY FLATTENING THROUGH MIDWEEK. THERE IS ALSO
OVERALL DEPICTION OF A BROAD AND WEAK UPPER LOW OVER THE SE
US...PART OF WHICH MAY SHEAR NE DURING THE WEEK. PREDICTABILITY ON
THE EVOLUTION OF THIS FEATURE IS LOW. OTHERWISE...DECENT AGREEMENT
ON THE APPROACH OF A NORTHERN STREAM SHORTWAVE LATE IN THE
WEEK...BUT STRENGTH AND TIMING IS AGAIN IN QUESTION.
CANADIAN HIGH PRESSURE BUILDS SOUTH OVER AND EAST OF THE REGION
SATURDAY. THIS WILL MAINTAIN A COOL AND DRY CANADIAN MARITIME
AIRMASS OVER THE REGION. ALONG THE COAST...POTENTIAL EXISTS FOR A
HIGH RIP CURRENT RISK SAT DUE TO 5 FT EASTERLY SWELLS/WAVES. HIGHS
SHOULD RUN NEAR SEASONABLE...UPPER 70S/LOWER 80S.
DRY AND VERY WARM TO HOT CONDITIONS ARE EXPECTED EARLY TO MID NEXT
WEEK AS HIGH PRESSURE SINKS SE OF THE REGION AND EVENTUALLY MERGES
WITH BERMUDA HIGH. A STEADY MODERATION IN HEAT AND HUMIDITY IS
LIKELY SUN THROUGH WED...WITH HIGHS INCREASING TO 5 TO 10 DEGREES
ABOVE SEASONABLE THROUGH THE EARLY WEEK PERIOD. GENERALLY UPPER 80S
TO LOWER 90S...WITH HEAT INDICES AT THIS POINT LOOKING JUST NEAR OR
SLIGHTLY HIGHER THAN TEMPS.
THE CAVEAT IN THE FORECAST FOR NEXT WEEK IS THAT WITH THE WEAK UPPER
LOW EXTENDING INTO THE WESTERN ATLANTIC...THERE IS POTENTIAL FOR
SOME TYPE OF SUBTROPICAL TROUGH LIFTING INTO THE MID ATLANTIC REGION
EARLY/MID WEEK. THIS WOULD POSE POTENTIAL FOR INCREASED CLOUD COVER
AND PERHAPS EVEN SOME SHOWERS DURING THE EARLY TO MID WEEK.
POTENTIAL IN THIS OCCURRENCE IS LOW AT THIS POINT.
OTHERWISE...POTENTIAL EXISTS FOR RIDGING TO FLATTEN ENOUGH BY
THURSDAY FOR APPROACH OF A WEAK SHORTWAVE AND ASSOCIATED COLD FRONT
BRINGING A CHANCE FOR SHOWERS AND THUNDERSTORMS. THIS WOULD ALSO
ALLOW FOR A COOLER AIRMASS TO INFILTRATE THE AREA.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
A COLD FRONT MOVE ACROSS THE AREA TONIGHT. HIGH PRESSURE STARTS
TO BUILD INTO THE REGION ON FRIDAY
VFR THROUGH MIDNIGHT. ISOLATED SHOWERS OR THUNDERSTORMS OVERNIGHT.
CONFIDENCE IN OCCURRENCE IS TOO LOW FOR INCLUSION IN TAFS.
MVFR CIGS ARE LIKELY EARLY FRIDAY MORNING WITH CIGS FALLING TO
2-3KFT. THERE MAY BE A FEW ISOLATED LOCATIONS WHICH FALL BELOW
2KFT. A GRADUAL IMPROVEMENT IN CIGS IS THEN LIKELY DURING THE
AFTERNOON.
SEA BREEZES ALONG THE COAST THIS AFTERNOON. WINDS BECOME LIGHT
AND VARIABLE THIS EVENING...BUT BECOME NE BEHIND THE FRONT. WINDS
INCREASE FRIDAY MORNING TO 10-15 KT...WITH GUSTS TO 20 KT.
...NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: AN OCCASIONAL GUST INTO THE TEENS POSSIBLE
LATE THIS AFTERNOON.
KLGA FCSTER COMMENTS: LOW TO MODERATE CONFIDENCE IN OCCURRENCE AND
TIMING OF SEABREEZE.
KEWR FCSTER COMMENTS: LOW TO MODERATE CONFIDENCE IN OCCURRENCE AND
TIMING OF SEABREEZE.
KTEB FCSTER COMMENTS: LOW CONFIDENCE OF SEABREEZE OCCURRING THIS
AFTERNOON.
KHPN FCSTER COMMENTS: LOW CONFIDENCE OF SEABREEZE OCCURRING THIS
AFTERNOON.
KISP FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.
.OUTLOOK FOR 18Z FRIDAY THROUGH TUESDAY...
.FRIDAY AFTERNOON...MVFR CIGS GIVING WAY TO VFR CIGS LATE.
NE-E WINDS G15-20KT POSSIBLE.
.FRIDAY NIGHT...VFR. E-NE WINDS G15-20KT POSSIBLE.
.SATURDAY-TUESDAY...VFR.
&&
.MARINE...
TRANQUIL CONDITIONS THIS EVENING WITH A SOUTHERLY SEA BREEZE.
A COLD FRONT PASSES THROUGH OVERNIGHT BRING IN A NE FLOW THAT
INCREASES THROUGH THE DAY ON FRIDAY. SCA IS ISSUES FOR THE OCEAN
STARTING AT 10 AM...THOUGH THE SCA CONDITION WILL SPREAD FROM EAST
TO WEST BETWEEN LATE MORNING AND EARLY AFTERNOON. POTENTIAL FOR
SMALL CRAFT ADVISORY LEVEL CONDITIONS TO CONTINUE ON THE OCEAN
INTO SATURDAY MORNING...THEN GRADUALLY SUBSIDING BELOW SCA LEVELS
BY SAT NIGHT AS HIGH PRESSURE BUILDS OVERHEAD.
THEREAFTER...SUB SCA CONDS EXPECTED THROUGH EARLY NEXT WEEK IN A WEAK
PRESSURE GRADIENT AS HIGH PRESSURE SINKS SE OF THE REGION.
&&
.FIRE WEATHER...
SEE SPECIAL ISSUANCE OF FIRE WEATHER PLANNING FORECAST RELATED TO
GUSTY WINDS TOMORROW.
FNUS51 KOKX / NYCFWFOKX
&&
.HYDROLOGY...
NO WIDESPREAD SIGNIFICANT RAINFALL IS FORECAST THROUGH THE MIDDLE
OF NEXT WEEK.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM FRIDAY TO 6 AM EDT SATURDAY
FOR ANZ350-353-355.
&&
$$
SYNOPSIS...TONGUE/NV
NEAR TERM...TONGUE
SHORT TERM...TONGUE
LONG TERM...NV
AVIATION...BC
MARINE...TONGUE/NV
FIRE WEATHER...
HYDROLOGY...TONGUE
AREA FORECAST DISCUSSION
NWS ALBANY NY
203 PM EDT THU SEP 3 2015
.SYNOPSIS...
A WEAK COLD FRONT WILL MOVE ACROSS THE REGION THIS
AFTERNOON INTO TONIGHT. THIS WILL BE THE MAIN FOCUS MECHANISM FOR
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS...WITH THE BEST
PROBABILITIES ACROSS THE HIGHER TERRAIN. THEREAFTER...HIGH PRESSURE
BUILDS ACROSS THE REGION FOR THE HOLIDAY WEEKEND WITH MAINLY DRY
CONDITIONS AND ABOVE NORMAL TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 135 PM EDT...THE COLD FRONT CONTINUES TO MOVE SOUTHWARD
ACROSS THE ADIRONDACKS. THE 0-6 KM BULK WIND SHEAR CONTINUES TO
VERY WEAK WITH LESS THAN 20KTS OVER THE NRN TIER OF THE FCST AREA.
THE ISOLD CELLS THAT FORMED ALONG THE RIM OF THE FOOTHILLS OF THE
ADIRONDACKS HAVE EXHIBITED PULSE TYPE CHARACTERISTICS...AS THEY
TAP INTO MODERATE INSTABILITY IN THE 1000-2000 J/KG RANGE BASED ON
THE LATEST SPC MESO-ANALYSIS PAGE. THE STEEPER MID LEVEL LAPSE
RATES ARE WEST OF THE ALY FCST AREA TOO. THE BEST CLOUD TO GROUND
LTG IS WITH THE CELL OVER SRN LEWIS/NRN ONEIDA COUNTIES...WEST OF
THE FCST AREA. EXPECTING MAINLY ISOLD TO PERHAPS SCT SHOWERS AND
THUNDERSTORMS WITH A LOCALLY HEAVY BURST OF RAIN. CAN NOT RULE OUT
A ROGUE SEVERE DUE TO PCPN LOADING INTO THE CELLS...AND CAPE
VALUES OF 1000 J/KG ESPECIALLY NORTH AND WEST OF ALY. PWATS HAVE
RISEN INTO THE 1-1.5" RANGE...SO SOME LOCALLY HEAVY RAINFALL IS
POSSIBLE. IT IS INTERESTING THAT THE LATEST HRRR HAS THE
CONVECTION WEAKEN AS IS MOVES SOUTH OF THE CAPITAL REGION/MOHAWK
VALLEY...AND KEEPS IT ISOLD.
TEMPERATURES WERE ADJUSTED A FEW DEGREES UP INTO THE U80S FROM
THE CAPITAL DISTRICT SOUTH AND EAST DUE TO MORE HEATING...WITH
U80S TO NEAR 90F IN SOME OF THE VALLEYS AREAS...WITH LOWER TO M80S
OVER THE MTNS. FURTHER NORTH EXPECT M70S TO M80S.
TONIGHT RESIDUAL CONVECTION SHOULD DISSIPATE AS SURFACE
ANTICYCLONE BUILDS IN FROM NORTHEAST CANADA. TRENDS IN THE MODEL
SUITE SUGGEST LOW LEVEL MOISTURE FROM THE ENE TRAJECTORIES ALONG
WITH UPSLOPE CONDITIONS INTO THE GREENS...BERKS AND NW CT AND SLOW
MOVEMENT OF THE FRONTAL MOVEMENT SOUTH OF I90 COULD KEEP CLOUDS A
BIT LONGER AND PERHAPS AN ISOLATED SHOWER UNTIL SHORTLY AFTER
MIDNIGHT. MOS VALUES OVERNIGHT ARE VERY CLOSE AND A BLENDED
APPROACH WAS UTILIZED. FOG POTENTIAL IS NOT THAT CLEAR AT THIS
TIME AS WE WATCH THE POTENTIAL FOR STRATUS DEVELOPMENT.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
FRIDAY...STILL SOME QUESTION JUST HOW MUCH LOW LEVEL STRATUS WILL
BE ACROSS THE REGION AS THE GFS IS MORE AGGRESSIVE THAN THE NAM.
HOWEVER...THEY BOTH AGREE THE WEAKENING FRONTAL BOUNDARY MAY GET
HUNG UP ALONG THE I84 CORRIDOR WHERE WE WILL KEEP THE SLIGHT
CHANCE POPS AT THIS TIME ALONG WITH ADDITIONAL CLOUD COVERAGE.
OTHERWISE...BREAKS IN THE CLOUD COVERAGE AND AS H925-850 COOL OFF
FROM THE ENE INTO THE LOWER TEENS...THIS SHOULD YIELD EVEN COOLER
AFTERNOON HIGHS WITH NEAR 80F FOR VALLEY LOCATIONS WITH MAINLY 70S
FOR THE ENTIRE CWFA.
FRI NIGHT...A PLEASANT EVENING IS EXPECTED WITH GRADUAL CLEARING
TO MOSTLY CLEAR SKIES AND CALM WINDS...AS THE SFC HIGH MOVES OVER
NY AND NEW ENGLAND. IDEAL RADIATIONAL COOLING CONDITIONS WILL
OCCUR...AND LOWS WILL BE MAINLY IN THE LOWER TO M50S WITH A FEW
U40S IN THE SRN DACKS. SOME PATCHY OR AREAS OF RADIATIONAL FOG MAY
FORM...AND MAY NEED TO BE ADDED TO THE FCST LATER IN TIME FOR MORE
WIDESPREAD FOG.
SATURDAY...A GOOD DEAL OF SUNSHINE AS TEMPS WILL BE SLIGHTLY
WARMER THAN FRIDAY WITH A MID AND UPPER LEVEL RIDGE BUILDING IN
OVER THE NORTHEAST. A CLOSED ANTICYCLONE MAY SET UP OVER NY AND
NEW ENGLAND LATE IN THE DAY. H925-850 TEMPS REBOUND BACK INTO THE
MID TEENS CELSIUS ALONG WITH INCREASING SUBSIDENCE WITH THE MID
AND UPPER RIDGE...AND THE SFC ANTICYCLONE FOR 80S IN THE VALLEYS
AND 70S FOR THE TERRAIN.
SATURDAY NIGHT...BIG BUBBLE...LITTLE TROUBLE AS THE COMBINATION OF
CLEAR SKIES...CALM WINDS AND LONGER NOCTURNAL PERIOD SHOULD ALLOW
FOR RADIATIONAL FOG TO FORM ONCE AGAIN AND COULD BE EVEN MORE
WIDESPREAD. THIS WILL CONTINUE TO BE MONITORED AND EVALUATED IN
LATER FORECASTS. LOWS MAINLY INTO THE 50S FOR THE REGION.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
THE LONG TERM PORTION OF THE FORECAST WILL FEATURE ABOVE NORMAL
TEMPERATURES AND BELOW NORMAL PRECIPITATION...CONTINUING THE TREND
FROM THE SHORT TERM.
A RIDGE OF HIGH PRESSURE AT ALL LEVELS OF THE ATMOSPHERE WILL
PROVIDE THE DRY AND VERY WARM CONDITIONS THROUGH AT LEAST LABOR DAY.
500 MB HEIGHTS AND 850 MB TEMPERATURES ARE FORECAST TO BE +1 TO +2
STDEV ACCORDING TO THE GEFS WHICH WILL RESULT IN MID LEVEL CAPPING
SUPPRESSING CONVECTION WITH PLENTY OF SUNSHINE. NORMAL HIGH
TEMPERATURES FOR ALBANY BY EARLY NEXT WEEK WILL BE THE MID
70S...HOWEVER WE WILL EXPERIENCE TEMPERATURES IN THE MID TO UPPER
80S...WITH SOME TEMPS POSSIBLY APPROACHING 90 IN PORTIONS OF THE MID
HUDSON VALLEY BY MONDAY. OVERNIGHT LOW TEMPERATURES SHOULD FALL INTO
THE 50S TO LOWER 60S FOR MON AM...THEN MAINLY LOWER/MID 60S FOR MON
NT/TUE AM ALTHOUGH SOME 50S COULD STILL OCCUR IN PORTIONS OF THE
ADIRONDACKS AND EASTERN CATSKILLS...AS WELL AS PORTIONS OF THE
SOUTHERN GREENS AND IN THE BERKSHIRES. HUMIDITY LEVELS SHOULD REMAIN
SOMEWHAT COMFORTABLE THROUGH MONDAY.
THE NEXT CHANCE OF ANY PRECIPITATION ARRIVES ON TUESDAY AS A
WEAKENING FRONTAL BOUNDARY APPROACHES FROM THE NORTH AND WEST.
LATEST MODELS SUGGEST THAT THIS FRONT WEAKENS QUITE A BIT BEFORE
REACHING OUR REGION...AS THE BEST UPPER LEVEL SUPPORT SHEARS WELL N
AND W OF THE REGION. THIS ENERGY SHOULD FLATTEN OUT THE UPPER LEVEL
RIDGE A BIT. WILL ONLY INCLUDE SOME SLIGHT CHANCE TO LOW CHC POPS
FOR THE ADIRONDACKS FOR LATE TUE...AND SLIGHT CHC TUE NT INTO WED
FOR MAINLY THE NORTHERN HALF OF THE REGION. TUESDAY MAX TEMPS SHOULD
STILL REACH THE MID/UPPER 80S FOR MOST AREAS...EXCEPT FOR LOWER 80S
ACROSS HIGHER ELEVATIONS. ONLY SLIGHTLY COOLER CONDITIONS WILL OCCUR
BEHIND THE FRONT...LEAVING WELL ABOVE NORMAL READINGS TO PERSIST.
OVERNIGHT MINS FOR TUE NT/WED AM SHOULD FALL INTO THE LOWER/MID
60S...EXCEPT FOR 50S ACROSS SOME HIGHER ELEVATIONS.
THERE ARE SOME INDICATIONS THAT A STRONGER COLD FRONT MAY APPROACH
THE REGION LATE NEXT WEEK...BUT THIS REMAINS UNCERTAIN. FOR NOW...
ABOVE NORMAL TEMPERATURES CAN BE EXPECTED TO CONTINUE THROUGH THE
NEXT 7-10 DAYS.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
A WEAK COLD FRONT WILL SETTLE SOUTHWARD ACROSS THE TAF SITES THIS
AFTERNOON/EARLY EVENING. ISOLATED SHOWERS/THUNDERSTORMS WILL BE
POSSIBLE WITH OR JUST AHEAD OF THIS FRONT.
OUTSIDE OF ISOLATED SHOWERS/THUNDERSTORMS...VFR CONDITIONS ARE
EXPECTED AT THE KGFL/KPSF/KPOU/KALB TAF SITES THROUGH MUCH OF
TONIGHT. THE ISOLATED/SCATTERED NATURE OF THE CONVECTION THIS
AFTN/EVE MEANS IT IS DIFFICULT TO TIME WHEN ANY SHWR/TSTMS WILL
AFFECT A TAF SITE...SO HAVE ONLY INCLUDED VCSH IN THE TAF
FORECASTS.
LATER TONIGHT AND EARLY FRIDAY MORNING...MVFR/IFR FOG/STRATUS
POSSIBLE AT KGFL/KPSF...BUT NOT AS LIKELY AS THE PAST FEW NIGHTS
SINCE THE REGION WILL BE IN A DRIER AIRMASS AND THERE COULD BE A
LIGHT NORTHEASTERLY FLOW THROUGH THE NIGHT. NO FOG FORECAST FOR
KALB/KPOU. AFTER 14Z FRIDAY...ALL TAF WILL BE VFR ONCE AGAIN.
NORTHERLY WINDS AT 4 TO 8 KTS THIS AFTERNOON...WILL SHIFT TO
NORTHEASTERLY TONIGHT. THE WINDS COULD BECOME LIGHT AND VARIABLE
OR CALM LATE TONIGHT. NORTHEAST TO EAST WINDS ON FRIDAY AT 5 TO 10
KTS.
OUTLOOK...
FRI AFTN-LABOR DAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
OUR RECENT DRY WEATHER...AND MORE EXPECTED IN THE FORECAST...
CONTINUES TO BE MONITORED. HOWEVER...LOW LEVEL MOISTURE REMAINS
ELEVATED AND WITH THE APPROACH OF A WEAK COLD FRONT COULD TOUCH
OFF ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS LATER THIS
MORNING INTO THE AFTERNOON HOURS. MOST OF THIS ACTIVITY SHOULD
DISSIPATE FOR THE REGION TONIGHT BUT A SHOWER OR TWO MAY LINGER
SOUTH OF I90 INTO FRIDAY.
THE RH VALUES WILL FALL TO 45-60 PERCENT THIS AFTERNOON. AN
EXCELLENT RECOVERY IS LIKELY FRIDAY MORNING WITH MAXIMUM RH VALUES
ONCE AGAIN OF 90 TO 100 PERCENT.
THE WINDS WILL BE LIGHT AND VARIABLE IN DIRECTION THIS MORNING.
THE WINDS WILL THEN SHIFT TO THE NORTHWEST TO NORTH AT 5-15 MPH
THIS AFTERNOON...AND THEN WILL BECOME NORTH TO NORTHEAST AT 5 TO
10 MPH BY THIS EVENING.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED THE NEXT 5 DAYS ENDING LABOR DAY.
ISOLATED TO SCATTERED SHOWERS AND OR THUNDERSTORMS WILL BE
POSSIBLE TODAY...AS A BACKDOOR COLD FRONT MOVES SOUTHWARD ACROSS
THE REGION....OTHERWISE IT WILL BE DRY THROUGH THE PERIOD.
RAINFALL AMOUNTS MAY RANGE FROM A TENTH TO QUARTER INCH WITH
LOCALLY HIGHER AMOUNTS FROM ANY THUNDERSTORMS.
ABOVE NORMAL TEMPERATURES WILL CONTINUE THROUGH THE
HOLIDAY WEEKEND...AS HIGH PRESSURE DOMINATES. RIVER FLOWS WILL
REMAIN BELOW NORMAL FOR EARLY SEPTEMBER.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR
WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...BGM/WASULA
NEAR TERM...GJM/BGM/WASULA
SHORT TERM...BGM/WASULA
LONG TERM...KL/JPV
AVIATION...GJM
FIRE WEATHER...BGM/WASULA
HYDROLOGY...BGM/WASULA
AREA FORECAST DISCUSSION
NWS ALBANY NY
135 PM EDT THU SEP 3 2015
.SYNOPSIS...
A WEAK COLD FRONT WILL MOVE ACROSS THE REGION THIS
AFTERNOON INTO TONIGHT. THIS WILL BE THE MAIN FOCUS MECHANISM FOR
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS...WITH THE BEST
PROBABILITIES ACROSS THE HIGHER TERRAIN. THEREAFTER...HIGH PRESSURE
BUILDS ACROSS THE REGION FOR THE HOLIDAY WEEKEND WITH MAINLY DRY
CONDITIONS AND ABOVE NORMAL TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 135 PM EDT...THE COLD FRONT CONTINUES TO MOVE SOUTHWARD
ACROSS THE ADIRONDACKS. THE 0-6 KM BULK WIND SHEAR CONTINUES TO
VERY WEAK WITH LESS THAN 20KTS OVER THE NRN TIER OF THE FCST AREA.
THE ISOLD CELLS THAT FORMED ALONG THE RIM OF THE FOOTHILLS OF THE
ADIRONDACKS HAVE EXHIBITED PULSE TYPE CHARACTERISTICS...AS THEY
TAP INTO MODERATE INSTABILITY IN THE 1000-2000 J/KG RANGE BASED ON
THE LATEST SPC MESO-ANALYSIS PAGE. THE STEEPER MID LEVEL LAPSE
RATES ARE WEST OF THE ALY FCST AREA TOO. THE BEST CLOUD TO GROUND
LTG IS WITH THE CELL OVER SRN LEWIS/NRN ONEIDA COUNTIES...WEST OF
THE FCST AREA. EXPECTING MAINLY ISOLD TO PERHAPS SCT SHOWERS AND
THUNDERSTORMS WITH A LOCALLY HEAVY BURST OF RAIN. CAN NOT RULE OUT
A ROGUE SEVERE DUE TO PCPN LOADING INTO THE CELLS...AND CAPE
VALUES OF 1000 J/KG ESPECIALLY NORTH AND WEST OF ALY. PWATS HAVE
RISEN INTO THE 1-1.5" RANGE...SO SOME LOCALLY HEAVY RAINFALL IS
POSSIBLE. IT IS INTERESTING THAT THE LATEST HRRR HAS THE
CONVECTION WEAKEN AS IS MOVES SOUTH OF THE CAPITAL REGION/MOHAWK
VALLEY...AND KEEPS IT ISOLD.
TEMPERATURES WERE ADJUSTED A FEW DEGREES UP INTO THE U80S FROM
THE CAPITAL DISTRICT SOUTH AND EAST DUE TO MORE HEATING...WITH
U80S TO NEAR 90F IN SOME OF THE VALLEYS AREAS...WITH LOWER TO M80S
OVER THE MTNS. FURTHER NORTH EXPECT M70S TO M80S.
TONIGHT RESIDUAL CONVECTION SHOULD DISSIPATE AS SURFACE
ANTICYCLONE BUILDS IN FROM NORTHEAST CANADA. TRENDS IN THE MODEL
SUITE SUGGEST LOW LEVEL MOISTURE FROM THE ENE TRAJECTORIES ALONG
WITH UPSLOPE CONDITIONS INTO THE GREENS...BERKS AND NW CT AND SLOW
MOVEMENT OF THE FRONTAL MOVEMENT SOUTH OF I90 COULD KEEP CLOUDS A
BIT LONGER AND PERHAPS AN ISOLATED SHOWER UNTIL SHORTLY AFTER
MIDNIGHT. MOS VALUES OVERNIGHT ARE VERY CLOSE AND A BLENDED
APPROACH WAS UTILIZED. FOG POTENTIAL IS NOT THAT CLEAR AT THIS
TIME AS WE WATCH THE POTENTIAL FOR STRATUS DEVELOPMENT.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
FRIDAY...STILL SOME QUESTION JUST HOW MUCH LOW LEVEL STRATUS WILL
BE ACROSS THE REGION AS THE GFS IS MORE AGGRESSIVE THAN THE NAM.
HOWEVER...THEY BOTH AGREE THE WEAKENING FRONTAL BOUNDARY MAY GET
HUNG UP ALONG THE I84 CORRIDOR WHERE WE WILL KEEP THE SLIGHT
CHANCE POPS AT THIS TIME ALONG WITH ADDITIONAL CLOUD COVERAGE.
OTHERWISE...BREAKS IN THE CLOUD COVERAGE AND AS H925-850 COOL OFF
FROM THE ENE INTO THE LOWER TEENS...THIS SHOULD YIELD EVEN COOLER
AFTERNOON HIGHS WITH NEAR 80F FOR VALLEY LOCATIONS WITH MAINLY 70S
FOR THE ENTIRE CWFA.
FRI NIGHT...A PLEASANT EVENING IS EXPECTED WITH GRADUAL CLEARING
TO MOSTLY CLEAR SKIES AND CALM WINDS...AS THE SFC HIGH MOVES OVER
NY AND NEW ENGLAND. IDEAL RADIATIONAL COOLING CONDITIONS WILL
OCCUR...AND LOWS WILL BE MAINLY IN THE LOWER TO M50S WITH A FEW
U40S IN THE SRN DACKS. SOME PATCHY OR AREAS OF RADIATIONAL FOG MAY
FORM...AND MAY NEED TO BE ADDED TO THE FCST LATER IN TIME FOR MORE
WIDESPREAD FOG.
SATURDAY...A GOOD DEAL OF SUNSHINE AS TEMPS WILL BE SLIGHTLY
WARMER THAN FRIDAY WITH A MID AND UPPER LEVEL RIDGE BUILDING IN
OVER THE NORTHEAST. A CLOSED ANTICYCLONE MAY SET UP OVER NY AND
NEW ENGLAND LATE IN THE DAY. H925-850 TEMPS REBOUND BACK INTO THE
MID TEENS CELSIUS ALONG WITH INCREASING SUBSIDENCE WITH THE MID
AND UPPER RIDGE...AND THE SFC ANTICYCLONE FOR 80S IN THE VALLEYS
AND 70S FOR THE TERRAIN.
SATURDAY NIGHT...BIG BUBBLE...LITTLE TROUBLE AS THE COMBINATION OF
CLEAR SKIES...CALM WINDS AND LONGER NOCTURNAL PERIOD SHOULD ALLOW
FOR RADIATIONAL FOG TO FORM ONCE AGAIN AND COULD BE EVEN MORE
WIDESPREAD. THIS WILL CONTINUE TO BE MONITORED AND EVALUATED IN
LATER FORECASTS. LOWS MAINLY INTO THE 50S FOR THE REGION.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
THE LONG TERM PORTION OF THE FORECAST WILL FEATURE ABOVE NORMAL
TEMPERATURES AND BELOW NORMAL PRECIPITATION...CONTINUING THE TREND
FROM THE SHORT TERM.
A RIDGE OF HIGH PRESSURE AT ALL LEVELS OF THE ATMOSPHERE WILL
PROVIDE THE DRY AND VERY WARM CONDITIONS THROUGH AT LEAST LABOR DAY.
500 MB HEIGHTS AND 850 MB TEMPERATURES ARE FORECAST TO BE +1 TO +2
STDEV ACCORDING TO THE GEFS WHICH WILL RESULT IN MID LEVEL CAPPING
SUPPRESSING CONVECTION WITH PLENTY OF SUNSHINE. NORMAL HIGH
TEMPERATURES FOR ALBANY BY EARLY NEXT WEEK WILL BE THE MID
70S...HOWEVER WE WILL EXPERIENCE TEMPERATURES IN THE MID TO UPPER
80S...WITH SOME TEMPS POSSIBLY APPROACHING 90 IN PORTIONS OF THE MID
HUDSON VALLEY BY MONDAY. OVERNIGHT LOW TEMPERATURES SHOULD FALL INTO
THE 50S TO LOWER 60S FOR MON AM...THEN MAINLY LOWER/MID 60S FOR MON
NT/TUE AM ALTHOUGH SOME 50S COULD STILL OCCUR IN PORTIONS OF THE
ADIRONDACKS AND EASTERN CATSKILLS...AS WELL AS PORTIONS OF THE
SOUTHERN GREENS AND IN THE BERKSHIRES. HUMIDITY LEVELS SHOULD REMAIN
SOMEWHAT COMFORTABLE THROUGH MONDAY.
THE NEXT CHANCE OF ANY PRECIPITATION ARRIVES ON TUESDAY AS A
WEAKENING FRONTAL BOUNDARY APPROACHES FROM THE NORTH AND WEST.
LATEST MODELS SUGGEST THAT THIS FRONT WEAKENS QUITE A BIT BEFORE
REACHING OUR REGION...AS THE BEST UPPER LEVEL SUPPORT SHEARS WELL N
AND W OF THE REGION. THIS ENERGY SHOULD FLATTEN OUT THE UPPER LEVEL
RIDGE A BIT. WILL ONLY INCLUDE SOME SLIGHT CHANCE TO LOW CHC POPS
FOR THE ADIRONDACKS FOR LATE TUE...AND SLIGHT CHC TUE NT INTO WED
FOR MAINLY THE NORTHERN HALF OF THE REGION. TUESDAY MAX TEMPS SHOULD
STILL REACH THE MID/UPPER 80S FOR MOST AREAS...EXCEPT FOR LOWER 80S
ACROSS HIGHER ELEVATIONS. ONLY SLIGHTLY COOLER CONDITIONS WILL OCCUR
BEHIND THE FRONT...LEAVING WELL ABOVE NORMAL READINGS TO PERSIST.
OVERNIGHT MINS FOR TUE NT/WED AM SHOULD FALL INTO THE LOWER/MID
60S...EXCEPT FOR 50S ACROSS SOME HIGHER ELEVATIONS.
THERE ARE SOME INDICATIONS THAT A STRONGER COLD FRONT MAY APPROACH
THE REGION LATE NEXT WEEK...BUT THIS REMAINS UNCERTAIN. FOR NOW...
ABOVE NORMAL TEMPERATURES CAN BE EXPECTED TO CONTINUE THROUGH THE
NEXT 7-10 DAYS.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
A WEAK COLD FRONT WILL SETTLE SOUTHWARD ACROSS THE TAF SITES THIS
AFTERNOON/EARLY EVENING. ISOLATED SHOWERS/THUNDERSTORMS WILL BE
POSSIBLE WITH OR JUST AHEAD OF THIS FRONT.
AREAS OF LOW CLOUDS/FOG SHOULD DISSIPATE AT KGFL AND KPSF BETWEEN
12Z-14Z/THU. THEREAFTER...VFR CONDITIONS ARE EXPECTED...OUTSIDE
OF ISOLATED SHOWERS/THUNDERSTORMS WHICH SHOULD DEVELOP BETWEEN
18Z- 22Z/THU. MOST OF THE CONVECTION IS EXPECTED TO REMAIN WEST
AND EAST OF THE TAF SITES...BUT CAN NOT RULE OUT A COUPLE
IMPACTING THE TAF SITES LATER THIS AFTERNOON. BRIEF PERIODS OF
MVFR/IFR VSBYS COULD OCCUR WITHIN THE CORES OF ANY
SHOWERS/THUNDERSTORMS.
CONVECTION SHOULD DECREASE AFTER 00Z/FRI...WITH MAINLY VFR
CONDITIONS CONTINUING THROUGH 06Z/FRI.
SOME LOW CLOUDS MAY DEVELOP AND/OR SPREAD WESTWARD BETWEEN 09Z-
12Z/FRI...ESP AT KPSF AND KPOU. GENERALLY MVFR CIGS WILL BE
POSSIBLE...ALTHOUGH KPSF COULD APPROACH IFR CIGS.
LIGHT/VARIABLE WINDS SHOULD PERSIST THROUGH 13Z/THU...THEN TREND
INTO THE NORTH TO NORTHWEST AT 5-10 KT THIS AFTERNOON. WINDS WILL
THEN SHIFT INTO THE N TO NE BETWEEN 01Z-04Z/FRI IN THE WAKE OF THE
COLD FRONT...AT 5-10 KT...ALTHOUGH COULD BRIEFLY GUST INTO THE
10-20 KT RANGE...ESP AT KGFL DUE TO CHANNELING DOWN THE UPPER
HUDSON/CHAMPLAIN VALLEY AND LAKE GEORGE.
OUTLOOK...
THU NT-LABOR DAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
OUR RECENT DRY WEATHER...AND MORE EXPECTED IN THE
FORECAST...CONTINUES TO BE MONITORED. HOWEVER...LOW LEVEL MOISTURE
REMAINS ELEVATED AND WITH THE APPROACH OF A WEAK COLD FRONT COULD
TOUCH OFF ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS LATER
THIS MORNING INTO THE AFTERNOON HOURS. MOST OF THIS ACTIVITY
SHOULD DISSIPATE FOR THE REGION TONIGHT BUT A SHOWER OR TWO MAY
LINGER SOUTH OF I90 INTO FRIDAY.
THE RH VALUES WILL FALL TO 45-60 PERCENT THIS AFTERNOON. AN
EXCELLENT RECOVERY IS LIKELY FRIDAY MORNING WITH MAXIMUM RH VALUES
ONCE AGAIN OF 90 TO 100 PERCENT.
THE WINDS WILL BE LIGHT AND VARIABLE IN DIRECTION THIS MORNING.
THE WINDS WILL THEN SHIFT TO THE NORTHWEST TO NORTH AT 5-15 MPH
THIS AFTERNOON...AND THEN WILL BECOME NORTH TO NORTHEAST AT 5 TO
10 MPH BY THIS EVENING.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED THE NEXT 5 DAYS ENDING LABOR DAY.
ISOLATED TO SCATTERED SHOWERS AND OR THUNDERSTORMS WILL BE
POSSIBLE TODAY...AS A BACKDOOR COLD FRONT MOVES SOUTHWARD ACROSS
THE REGION....OTHERWISE IT WILL BE DRY THROUGH THE PERIOD.
RAINFALL AMOUNTS MAY RANGE FROM A TENTH TO QUARTER INCH WITH
LOCALLY HIGHER AMOUNTS FROM ANY THUNDERSTORMS.
ABOVE NORMAL TEMPERATURES WILL CONTINUE THROUGH THE
HOLIDAY WEEKEND...AS HIGH PRESSURE DOMINATES. RIVER FLOWS WILL
REMAIN BELOW NORMAL FOR EARLY SEPTEMBER.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR
WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...BGM/WASULA
NEAR TERM...GJM/BGM/WASULA
SHORT TERM...BGM/WASULA
LONG TERM...KL/JPV
AVIATION...KL
FIRE WEATHER...BGM/WASULA
HYDROLOGY...BGM/WASULA
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1225 PM CDT THU SEP 3 2015
.UPDATE...1153 AM CDT
MINOR REFINEMENTS TO THE TIMING OF POPS TODAY. THIS AFTERNOON...CU
STARTING TO BLOSSOM ACROSS THE REGION WITH THE BEST DEVELOPMENT
SO FAR ACROSS FAR NORTHEAST IL INCLUDING LAKE COUNTY AND NORTHERN
COOK COUNTY. CANNOT RULE AN ISOLATED STORM DEVELOPING OVER THESE
AREAS EARLY THIS AFTERNOON WITH RAP SOUNDINGS SHOWING THE
BOUNDARY LAYER UNCAPPED...HOWEVER FORCING IS FAIRLY NON-EXISTENT
WITH WEAK MID LEVEL HEIGHT RISES IN PLACE WHICH SHOULD KEEP
CONVECTION IN CHECK MOST OF THE AFTERNOON. THIS WILL CHANGE
STARTING EARLY THIS EVENING AS A LAKE BREEZE POSSIBLY ENHANCED BY
OUTFLOW FROM CONVECTION OVER THE LAKE DROPS INTO NORTHERN
ILLINOIS. THIS IS EXPECTED TO SERVE THE FOCUS FOR ISOLATED TO
SCATTERED THUNDERSTORMS. LATEST RUNS OF THE HRRR AND RAP SHOW THIS
OCCURRING STARTING AROUND 22-00Z WITH THE NAM RUNNING SLIGHTLY
SLOWER. BUMPED BACK THE TIMING OF THE HIGHEST POPS TO BETTER MATCH
THESE THOUGHTS.
DEUBELBEISS
&&
.SHORT TERM...
310 AM CDT
THROUGH FRIDAY...
PRIMARY CONCERN IN SHORT TERM IS CONVECTIVE CHANCES TODAY AND
SECONDARILY TEMPS. MCV OVER NORTHERN LAKE MICHIGAN WILL CONTINUE TO
PUSH VERY SLOWLY EAST INTO NORTHERN LOWER MICHIGAN TODAY. TRAILING
WEST-EAST LINE OF STORMS ACROSS EAST CENTRAL WISCONSIN HAS BEEN
SAGGING VERY SLOWLY SOUTHWARD AND AT ITS CURRENT PACE LOOKS TO MAKE
IT INTO THE HEART OF OUR CWA BY EARLY AFTERNOON. GIVEN RELATIVELY
WEAK CAPPING AND UNSEASONABLY WARM/HUMID AIR MASS QUITE PLAUSIBLE
THAT ISOLD TO POSSIBLY SCTD THUNDERSTORMS COULD DEVELOP ALONG THIS
BOUNDARY THIS AFTERNOON OR PERHAPS ALONG LAKE BREEZE LATE THIS
AFTERNOON AND EVENING. CONVECTIVE ALLOWING MODELS HAVE BEEN HAVING
ABSOLUTE FITS HANDLING THIS WEAKLY FORCED CONVECTION THE PAST COUPLE
DAYS WHICH LENDS ITSELF TO LOWER THAN AVERAGE CONFIDENCE IN HOW
THINGS EVOLVE TODAY. WITH SHORTWAVE MOVING EAST TONIGHT AND SOME
NOCTURNAL STABILIZATION WOULD ANTICIPATE ANY CONVECTION THAT DOES
DEVELOP TO DISSIPATE THIS EVENING.
ASSUMING CONVECTION AND CLOUD COVER ARE NOT OVERLY EXTENSIVE THROUGH
MID-AFTERNOON...WHICH WOULD APPEAR TO BE A GOOD ASSUMPTION AT THIS
POINT...THEN HIGHS TODAY WOULD LIKELY BE IN THE BALL PARK OF WHERE
THEY WERE YESTERDAY AROUND 90 DEGREES. IF CONVECTIVE OUTFLOW
ENHANCES A LAKE BREEZE THEN IT COULD TURN COOLER NEAR THE LAKE THIS
AFTERNOON...BUT THIS DOESNT APPEAR TO BE MOST LIKELY SCENARIO AT
THIS TIME SO DIDNT REFLECT THAT IN WIND/TEMP GRIDS.
WEAKNESS BETWEEN MAIN UPPER RIDGE AND WEAK RIDGE OVER QUEBEC SHOULD
RESULT IN WEAK CAPPING AT BEST FRIDAY AND A CONTINUED SLIGHT CHANCE
OF AT LEAST ISOLATED STORMS IN THE AFTERNOON AND EVENING. LAKE
BREEZE LOOKS MORE LIKELY TO KEEP LAKESHORE AREAS COOLER FRIDAY BUT
INLAND TEMPS SHOULD AGAIN WARM INTO THE UPPER 80S TO NEAR 90.
IZZI
&&
.LONG TERM...
310 AM CDT
FRIDAY NIGHT THROUGH WEDNESDAY...
UPPER RIDGE LOOKS TO FLEX A BIT MORE NORTHEAST INTO THE REGION OVER
THE WEEKEND AND WHILE ISOLATED STORMS CANNOT TOTALLY BE RULED
OUT...CHANCES LOOK SLIME WITH SATURDAY AND SUNDAY GENERALLY LOOKING
MAINLY RAIN FREE AT THIS POINT. TEMPERATURES LOOKS TO REMAIN VERY
WARM TO BORDERLINE HOT AND CONTINUED HUMID. HIGHS SHOULD EASILY
CLIMB INTO THE UPPER 80S WITH LOW 90S CERTAINLY POSSIBLE. LAKE
BREEZE IS POSSIBLE SATURDAY BUT LOOKS LESS LIKELY AT THIS POINT ON
SUNDAY.
COLD FRONT SHOULD BEGIN TO APPROACH FROM THE NORTHWEST SUNDAY NIGHT
OR MONDAY. IN GENERAL...MEDIUM RANGE GUIDANCE HAS SPED UP THE FRONT
SOME COMPARED TO RUNS 24 HOURS AGO. NOT CONVINCED IT WILL BE THIS
QUICK AND WORRIED THAT BLENDED MODEL HIGHS IN THE MID 80S MONDAY MAY
END UP BEING A BIT TOO COOL...BUT GIVEN RECENT MODEL TRENDS DIDNT
MAKE ANY CHANGES AT THIS POINT. IT DOES APPEAR AS THOUGH WE COULD
GET A BREAK FROM THE LATE RESURGENCE OF SUMMER BY THE MIDDLE OF NEXT
WEEK WITH HIGHS RETURNING INTO THE 70S AGAIN.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* TSRA/SHRA POSSIBLE WITH INCREASING CHANCES LATER THIS AFTERNOON
AND EVENING...WITH ISOLATED ACTIVITY LINGERING OVERNIGHT.
* ABRUPT WIND SHIFT TO AN NNE DIRECTION LATE THIS AFTERNOON OR EARLY
EVENING WITH WINDS ABOVE 10 KT POSSIBLE FOR A BRIEF TIME.
* MVFR CIGS THIS EVENING.
KMD
//DISCUSSION...UPDATED 18Z...
DESTABILIZATION CONTINUES ACROSS THE AREA THIS AFTERNOON WITH A BIT
MORE WIDESPREAD CUMULUS DEVELOPMENT ONGOING. SW WINDS ARE STRONG
ENOUGH TO KEEP A LAKE BREEZE AT BAY FOR THIS AFTERNOON...BUT
ATTENTION SHIFTS TO SOUTHWARD MOVING FRONTAL BOUNDARY MAKING DECENT
HEADWAY DOWN THE WESTERN SHORE OF LAKE MICHIGAN. WINDS SHIFT TO AN
NNE DIRECTION BEHIND THIS BOUNDARY...AND TO THIS POINT WINDS HAVE
LARGELY HELD UNDER 10 KT. THIS SHOULD LARGELY BE THE TREND AS THE
BOUNDARY MOVES SOUTH LATER THIS AFTERNOON AND EVENING...THOUGH A
BRIEF PERIOD OF WINDS IN EXCESS OF 10 KT ARE POSSIBLE.
OTHER CONCERN IS WITH CONVECTION ALONG THE LAKE BREEZE/FRONT AS LOW
PRESSURE IN NORTHWEST WISCONSIN MOVES SOUTH. SOME GUIDANCE IS TRYING
TO BREAK OUT SHOWERS THIS AFTERNOON...WHICH IS CERTAINLY POSSIBLE
GIVEN THE UNSTABLE ENVIRONMENT...BUT WITH THE FRONT/UPPER LOW NOT
ARRIVING UNTIL LATER THIS AFTERNOON AND EVENING...THIS STILL APPEARS
TO BE THE BEST FOCUS FOR THUNDERSTORMS. TIMING CONFIDENCE IS ONLY
MEDIUM AT THIS POINT...AND COVERAGE CONCERNS PRECLUDES MORE THAN A
VCTS MENTION AS WELL. MVFR CLOUDS WILL ACCOMPANY THE WIND
SHIFT...WITH AT LEAST A PERIOD OF BROKEN CIGS THROUGH THE
EVENING....POSSIBLY LONGER.
THE BOUNDARY WILL LINGER OVER THE AREA IN THE OVERNIGHT HOURS...AND
ENERGY ON THE BACK SIDE OF THE UPPER LOW CENTER IN MICHIGAN WHICH
WILL STALL OUT WILL MEAN ISOLATED DEVELOPMENT MAY CONTINUE
OVERNIGHT. CONFIDENCE IN COVERAGE IS LOW...THUS THE DRY TAF
FORECAST FOR OVERNIGHT.
KMD
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* LOW-MEDIUM WITH TSRA/SHRA CHANCES/COVERAGE THROUGH THIS EVENING.
MEDIUM ON TIMING.
* MEDIUM-HIGH WITH WIND SPEED/DIRECTION...MEDIUM ON TIMING OF WIND
SHIFT AND IF IT WILL STAY UNDER 10 KT WHEN IT OCCURS.
* HIGH ON MVFR CLOUDS FORMING THIS EVENING...LOW ON HOW LONG THEY
LAST.
KMD
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR.
SATURDAY...SLIGHT CHANCE OF TSRA.
SUNDAY...CHANCE OF TSRA LATE.
MONDAY...CHANCE OF TSRA.
TUESDAY...SLIGHT CHANCE OF TSRA.
WEDNESDAY...CHANCE OF TSRA.
RODRIGUEZ
&&
.MARINE...
428 AM CDT
AS A BOUNDARY REMAINS SITUATED ACROSS THE NORTHERN PORTIONS OF
THE LAKE THIS MORNING...A VARYING WIND FIELD IS OCCURRING ACROSS
THE LAKE. OVER THE NORTH...EAST NORTHEAST WINDS ARE OCCURRING AND
ACROSS THE SOUTH...SOUTHWEST WINDS ARE BEING OBSERVED. THIS WILL
LIKELY PERSIST FOR MOST OF TODAY...BUT WITH THE SOUTHWEST WINDS
ACROSS THE SOUTHERN PART OF LAKE TURNING MORE SOUTHEAST THIS
AFTERNOON. INCREASED WINDS OVER THE NORTH HALF TO 10 TO 20 KT FOR
THIS MORNING BUT HAVE THEM DIMINISHING IN THE AFTERNOON.
HOWEVER...DO THINK ITS POSSIBLE THAT 10 TO 20 KT WINDS COULD STILL
BE POSSIBLE IN THE AFTERNOON. WAVES SHOULD STAY CONFINED TO 1 TO 3
FEET TODAY AND TONIGHT BUT WITH THUNDERSTORMS PUSHING OVER THE
LAKE EARLY THIS MORNING...ASSOCIATED HIGHER WINDS COULD HELP TO
BRIEFLY BUILD THESE WAVES.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1157 AM CDT THU SEP 3 2015
.UPDATE...
1153 AM CDT
MINOR REFINEMENTS TO THE TIMING OF POPS TODAY. THIS AFTERNOON...CU
STARTING TO BLOSSOM ACROSS THE REGION WITH THE BEST DEVELOPMENT
SO FAR ACROSS FAR NORTHEAST IL INCLUDING LAKE COUNTY AND NORTHERN
COOK COUNTY. CANNOT RULE AN ISOLATED STORM DEVELOPING OVER THESE
AREAS EARLY THIS AFTERNOON WITH RAP SOUNDINGS SHOWING THE
BOUNDARY LAYER UNCAPPED...HOWEVER FORCING IS FAIRLY NON-EXISTANT
WITH WEAK MID LEVEL HEIGHT RISES IN PLACE WHICH SHOULD KEEP
CONVECTION IN CHECK MOST OF THE AFTERNOON. THIS WILL CHANGE
STARTING EARLY THIS EVENING AS A LAKE BREEZE POSSIBLY ENHANCED BY
OUTFLOW FROM CONVECTION OVER THE LAKE DROPS INTO NORTHERN
ILLINOIS. THIS IS EXPECTED TO SERVE THE FOCUS FOR ISOLATED TO
SCATTERED THUNDERSTORMS. LATEST RUNS OF THE HRRR AND RAP SHOW THIS
OCCURRING STARTING AROUND 22-00Z WITH THE NAM RUNNING SLIGHTLY
SLOWER. BUMPED BACK THE TIMING OF THE HIGHEST POPS TO BETTER MATCH
THESE THOUGHTS.
DEUBELBEISS
&&
.SHORT TERM...
310 AM CDT
THROUGH FRIDAY...
PRIMARY CONCERN IN SHORT TERM IS CONVECTIVE CHANCES TODAY AND
SECONDARILY TEMPS. MCV OVER NORTHERN LAKE MICHIGAN WILL CONTINUE TO
PUSH VERY SLOWLY EAST INTO NORTHERN LOWER MICHIGAN TODAY. TRAILING
WEST-EAST LINE OF STORMS ACROSS EAST CENTRAL WISCONSIN HAS BEEN
SAGGING VERY SLOWLY SOUTHWARD AND AT ITS CURRENT PACE LOOKS TO MAKE
IT INTO THE HEART OF OUR CWA BY EARLY AFTERNOON. GIVEN RELATIVELY
WEAK CAPPING AND UNSEASONABLY WARM/HUMID AIR MASS QUITE PLAUSIBLE
THAT ISOLD TO POSSIBLY SCTD THUNDERSTORMS COULD DEVELOP ALONG THIS
BOUNDARY THIS AFTERNOON OR PERHAPS ALONG LAKE BREEZE LATE THIS
AFTERNOON AND EVENING. CONVECTIVE ALLOWING MODELS HAVE BEEN HAVING
ABSOLUTE FITS HANDLING THIS WEAKLY FORCED CONVECTION THE PAST COUPLE
DAYS WHICH LENDS ITSELF TO LOWER THAN AVERAGE CONFIDENCE IN HOW
THINGS EVOLVE TODAY. WITH SHORTWAVE MOVING EAST TONIGHT AND SOME
NOCTURNAL STABILIZATION WOULD ANTICIPATE ANY CONVECTION THAT DOES
DEVELOP TO DISSIPATE THIS EVENING.
ASSUMING CONVECTION AND CLOUD COVER ARE NOT OVERLY EXTENSIVE THROUGH
MID-AFTERNOON...WHICH WOULD APPEAR TO BE A GOOD ASSUMPTION AT THIS
POINT...THEN HIGHS TODAY WOULD LIKELY BE IN THE BALL PARK OF WHERE
THEY WERE YESTERDAY AROUND 90 DEGREES. IF CONVECTIVE OUTFLOW
ENHANCES A LAKE BREEZE THEN IT COULD TURN COOLER NEAR THE LAKE THIS
AFTERNOON...BUT THIS DOESNT APPEAR TO BE MOST LIKELY SCENARIO AT
THIS TIME SO DIDNT REFLECT THAT IN WIND/TEMP GRIDS.
WEAKNESS BETWEEN MAIN UPPER RIDGE AND WEAK RIDGE OVER QUEBEC SHOULD
RESULT IN WEAK CAPPING AT BEST FRIDAY AND A CONTINUED SLIGHT CHANCE
OF AT LEAST ISOLATED STORMS IN THE AFTERNOON AND EVENING. LAKE
BREEZE LOOKS MORE LIKELY TO KEEP LAKESHORE AREAS COOLER FRIDAY BUT
INLAND TEMPS SHOULD AGAIN WARM INTO THE UPPER 80S TO NEAR 90.
IZZI
&&
.LONG TERM...
310 AM CDT
FRIDAY NIGHT THROUGH WEDNESDAY...
UPPER RIDGE LOOKS TO FLEX A BIT MORE NORTHEAST INTO THE REGION OVER
THE WEEKEND AND WHILE ISOLATED STORMS CANNOT TOTALLY BE RULED
OUT...CHANCES LOOK SLIME WITH SATURDAY AND SUNDAY GENERALLY LOOKING
MAINLY RAIN FREE AT THIS POINT. TEMPERATURES LOOKS TO REMAIN VERY
WARM TO BORDERLINE HOT AND CONTINUED HUMID. HIGHS SHOULD EASILY
CLIMB INTO THE UPPER 80S WITH LOW 90S CERTAINLY POSSIBLE. LAKE
BREEZE IS POSSIBLE SATURDAY BUT LOOKS LESS LIKELY AT THIS POINT ON
SUNDAY.
COLD FRONT SHOULD BEGIN TO APPROACH FROM THE NORTHWEST SUNDAY NIGHT
OR MONDAY. IN GENERAL...MEDIUM RANGE GUIDANCE HAS SPED UP THE FRONT
SOME COMPARED TO RUNS 24 HOURS AGO. NOT CONVINCED IT WILL BE THIS
QUICK AND WORRIED THAT BLENDED MODEL HIGHS IN THE MID 80S MONDAY MAY
END UP BEING A BIT TOO COOL...BUT GIVEN RECENT MODEL TRENDS DIDNT
MAKE ANY CHANGES AT THIS POINT. IT DOES APPEAR AS THOUGH WE COULD
GET A BREAK FROM THE LATE RESURGENCE OF SUMMER BY THE MIDDLE OF NEXT
WEEK WITH HIGHS RETURNING INTO THE 70S AGAIN.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* TSRA/SHRA POSSIBLE LATE THIS AFTERNOON AND EVENING.
* ABRUPT WIND SHIFT TO AN ENE DIRECTION LATE THIS AFTERNOON OR
EARLY EVENING WITH WINDS ABOVE 10 KT POSSIBLE.
* MVFR CIGS THIS EVENING
RODRIGUEZ
//DISCUSSION...UPDATED 12Z...
VFR CONDITIONS AND LIGHT SOUTHERLY WINDS IN PLACE THIS
MORNING...WHILE ANY PRECIP ACROSS THE REGION IS CURRENTLY TO THE
NORTH OF ALL THE TERMINALS. THIS WILL LIKELY CONTINUE...WITH ANY
FURTHER DEVELOPMENT THIS MORNING STAYING TO THE NORTH/NORTHEAST.
INCREASING SOUTHWEST WINDS THROUGH MIDDAY/EARLY AFTERNOON WILL
LIKELY OBSERVE A WIND SHIFT TO THE EAST...OWING TO BOUNDARY/LAKE
BREEZE. LOWER CONFIDENCE WITH EXACT TIMING AS WELL AS SPEED BEHIND
THE FRONT. AT THIS TIME...THINK SPEEDS WILL STAY BELOW 10 KT.
HOWEVER...SOME GUIDANCE IS HINTING AT POSSIBLE SUSTAINED SPEEDS
ABOVE 10 KT THROUGH THIS EVENING. THIS BOUNDARY COULD ALSO SERVE
AS A FOCUS FOR PRECIP DEVELOPMENT THIS AFTERNOON INTO THE EVENING.
WITH AT LEAST SCATTERED DEVELOPMENT POSSIBLE...HAVE MAINTAINED A
VCSH IN THE TAFS. WILL NEED TO MONITOR SPEEDS BEHIND WIND SHIFT AS
WELL AS PRECIP CHANCES/COVERAGE LATER THIS AFTERNOON.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* LOW-MEDIUM WITH TSRA/SHRA CHANCES/COVERAGE THIS
AFTERNOON/EVENING. MEDIUM ON TIMING IF IT OCCURS.
* MEDIUM HIGH WITH WIND SPEED/DIRECTION...MEDIUM ON TIMING OF
WIND SHIFT AND IF IT WILL STAY UNDER 10 KT WHEN IT OCCURS.
* MEDIUM ON MVFR CLOUDS FORMING THIS EVENING...LOW ON HOW LONG
THEY LAST.
KMD
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR.
SATURDAY...SLIGHT CHANCE OF TSRA.
SUNDAY...CHANCE OF TSRA LATE.
MONDAY...CHANCE OF TSRA.
TUESDAY...SLIGHT CHANCE OF TSRA.
WEDNESDAY...CHANCE OF TSRA.
RODRIGUEZ
&&
.MARINE...
428 AM CDT
AS A BOUNDARY REMAINS SITUATED ACROSS THE NORTHERN PORTIONS OF
THE LAKE THIS MORNING...A VARYING WIND FIELD IS OCCURRING ACROSS
THE LAKE. OVER THE NORTH...EAST NORTHEAST WINDS ARE OCCURRING AND
ACROSS THE SOUTH...SOUTHWEST WINDS ARE BEING OBSERVED. THIS WILL
LIKELY PERSIST FOR MOST OF TODAY...BUT WITH THE SOUTHWEST WINDS
ACROSS THE SOUTHERN PART OF LAKE TURNING MORE SOUTHEAST THIS
AFTERNOON. INCREASED WINDS OVER THE NORTH HALF TO 10 TO 20 KT FOR
THIS MORNING BUT HAVE THEM DIMINISHING IN THE AFTERNOON.
HOWEVER...DO THINK ITS POSSIBLE THAT 10 TO 20 KT WINDS COULD STILL
BE POSSIBLE IN THE AFTERNOON. WAVES SHOULD STAY CONFINED TO 1 TO 3
FEET TODAY AND TONIGHT BUT WITH THUNDERSTORMS PUSHING OVER THE
LAKE EARLY THIS MORNING...ASSOCIATED HIGHER WINDS COULD HELP TO
BRIEFLY BUILD THESE WAVES.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS DES MOINES IA
332 PM CDT THU SEP 3 2015
.SHORT TERM /TONIGHT/...
ISSUED AT 332 PM CDT THU SEP 3 2015
MAIN FORECAST CONCERN WAS FOCUSED ON TEMPERATURES AND FOG
POTENTIAL OVER NORTHERN IOWA. OVERNIGHT LOWS LOOK TO FINALLY REACH
THE CROSSOVER TEMP BY B/T 07-09Z OVER THE NORTH AND LIKELY SEE FOG
DEVELOP DURING THAT TIME FRAME. NAM/SREF SUGGEST FOG DEVELOPING FROM
MCW TO EST AND POSSIBLY AS FAR SOUTH AS HIGHWAY 20. THE CAVEAT IS A
WEAK SHORTWAVE OVER NEBRASKA/SOUTH DAKOTA MAY BRING IN SOME HIGHER
CLOUDS TOWARDS FRIDAY MORNING...SO ONLY MENTIONED PATCHY FOG ATTM.
THE LATEST HRRR (03.18Z) AND EVEN THE GFS HAVE A HINT OF CONVECTION
DEVELOPING OVER THE NORTHWEST TOWARDS FRIDAY MORNING IN RESPONSE TO
THE LLJ DEVELOPING AND ASSOCIATED WITH AFOREMENTIONED WEAK
SHORTWAVE. THINKING THE NAM/ECMWF HAS A BETTER HANDLE ON TIMING AND
LOCATION AND LEFT FORECAST DRY.
.LONG TERM /FRIDAY THROUGH THURSDAY/...
ISSUED AT 332 PM CDT THU SEP 3 2015
PATTERN REMAINS SIMILAR THROUGH THE BEGINNING OF THE MID/LONG RANGE
WITH UPPER RIDGING IN PLACE ALOFT WITH A TROUGH DIGGING INTO THE
WESTERN US. A FEW WEAK IMPULSES WILL MOVE JUST TO THE WEST OF THE
CWA WHICH COULD LEAD TO SOME INCREASED CLOUDINESS...BUT OVERALL
CHANCE OF PRECIPITATION IS SMALL SO HAVE A DRY FORECAST INTO
SATURDAY. UPPER LEVEL RIDGE TO FLATTEN SOME OVER THE WEEKEND AS THE
WESTERN US TROUGH LIFTS NORTHEASTWARD INTO SOUTHERN CANADIAN PRAIRIE
PROVINCES BY LATE SUNDAY. SOUTHERLY FLOW WILL INCREASE AHEAD OF THIS
SYSTEM SATURDAY NIGHT INTO SUNDAY...WITH MOISTURE ADVECTION AND
MOISTURE TRANSPORT BECOMING ORIENTED INTO WESTERN IOWA. MAY SEE SOME
STORMS BUBBLE UP ACROSS THE WESTERN/NORTHWESTERN CWA...BUT OVERALL
WIDESPREAD PRECIPITATION CHANCES NOT EXPECTED UNTIL THE PASSAGE OF
THE COLD FRONT ASSOCIATED WITH THE CANADIAN SYSTEM SUNDAY NIGHT.
THIS FRONT WILL ELIMINATE THE CURRENT HOT AND MUGGY CONDITIONS...AS
H85 TEMPS DROP INTO THE TEENS BEHIND THE FRONT. LONG RANGE IN MODELS
IN SOME DISAGREEMENT INTO NEXT WEEK WITH HOW FAST TO PUSH THE FRONT
SOUTH...WITH THE EC HANGING THE FRONT UP ACROSS SOUTHERN IOWA WITH
CHANCES FOR STORMS CONTINUING INTO MONDAY/MONDAY NIGHT. GFS TRIES TO
PUSH IT INTO MISSOURI...WHICH WOULD KEEP IOWA DRIER MONDAY. FULL
LONGWAVE WESTERN US TROUGH TO SHOVE EAST TUESDAY WITH THE FRONT
LIFTING BACK NORTHWARD AS A WARM FRONT LATE MONDAY NIGHT/EARLY
TUESDAY BEFORE A STRONGER COLD FRONT PUSHES THROUGH LATE TUESDAY
INTO TUESDAY NIGHT. H85 TEMPS TO DROP ANOTHER CATEGORY INTO THE LOW
TEENS BEHIND THIS FRONT WITH HIGH PRESSURE EXPECTED TO BUILD IN FOR
THE REST OF THE WEEK. THIS SHOULD LEAD TO MAINLY DRY CONDITIONS FOR
MUCH OF WEDNESDAY INTO THE END OF THE WEEK. MODELS DO HINT AT A WEAK
TROUGH CLIPPING NORTHERN IOWA THURSDAY WHICH COULD BRING SOME
SPRINKLES TO MAINLY NORTHEASTERN IOWA. HAVE A SMALL AREA OF SLIGHT
CHANCE POP FOR THIS FEATURE. OTHERWISE RELEGATED POPS MAINLY TO THE
TIME PERIODS WITH THE FRONTAL PASSAGES WITH TEMPS EXPECTED TO FALL
MORE TOWARD OR SLIGHTLY BELOW THE SEASONAL AVERAGES.
&&
.AVIATION...03/18Z
ISSUED AT 1229 PM CDT THU SEP 3 2015
WITH THE UPPER LEVEL RIDGE FIRMLY PLANTED ABOVE...ANYTHING OF
CONSEQUENCE WILL STAY TO THE WEST AND NORTHWEST OF THE TAF SITES.
MODEL SOUNDINGS HINT AT SOME LOCALIZED FOG TOMORROW MORNING...BUT
WITH HRRR DEPICTING OTHERWISE AND LITTLE CHANGE OVERNIGHT
OTHERWISE...HAVE KEPT FOG MENTIONS OUT FOR THIS ITERATION.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...BEERENDS
AVIATION...CURTIS
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1236 PM CDT THU SEP 3 2015
...18Z AVIATION UPDATE...
.SHORT TERM /TODAY/...
ISSUED AT 335 AM CDT THU SEP 3 2015
PRECIPITATION CHANCES TODAY WILL BE MAIN FORECAST CONCERN. HAVE SEEN
DEVELOPMENT OF ONGOING LIGHT AND SCATTERED SHOWERS ACROSS SW
PORTIONS OF STATE...GENERALLY ALONG THE NOSE OF LLJ...AND EXPECT
THIS PRECIPITATION TO CONTINUE INTO THE EARLY MORNING
HOURS...DISSIPATING QUICKLY AFTER 12Z AS FORCING DIMINISHES. HAVE
TRENDED TOWARDS HIGH RES SOLUTIONS...THOUGH MAY BE TOO AGGRESSIVE
WITH EXTENT OF NORTHERN EDGE OF PRECIPITATION AND PERSISTENCE.
CHANCES FOR PRECIPITATION WILL THEN SHIFT TO THE NORTHEASTERN
PORTIONS OF THE CWA LATE IN THE PERIOD. MODELS INDICATE DECENT
INSTABILITY ACROSS THE AREA...THOUGH SOUNDINGS SHOWING A WEAK CAP
WHICH SHOULD BE SUFFICIENT TO KEEP PRECIPITATION CHANCES OUT OF CWA.
HAVE THEREFORE KEPT FORECAST DRY...WITH BEST FORCING FURTHER EAST OF
THE AREA. HOWEVER...DO NOT HAVE HIGH CONFIDENCE AND MAY SEE
THUNDERSTORMS DEVELOP IN THE AFTERNOON IN THIS AREA.
HAVE KEPT TEMPERATURES NEAR GOING...TOWARDS THE HIGHER GUIDANCE.
WITH GOOD SOUTHERLY SURFACE FLOW AND WARMER TEMPERATURES ALOFT
SHOULD SEE TEMPERATURES WARM TODAY. HUMID CONDITIONS WILL PERSIST
WITH HEAT INDEX VALUES GENERALLY 95-100 DEGREES IN THE AFTERNOON.
.LONG TERM /TONIGHT THROUGH WEDNESDAY/...
ISSUED AT 335 AM CDT THU SEP 3 2015
A FEW MORE DAYS OF SUMMER WHILE THE UPPER RIDGE REMAINS OVER THE
STATE. HIGH TEMPERATURES IN THE MID 80S TO LOWER 90S ARE EXPECTED TO
LAST THROUGH SUNDAY HOWEVER CHANGE IS ON THE WAY. SEVERAL FEATURES
TO MONITOR THROUGH THE PERIOD. THE FIRST WILL BE THE INCREASING
MONSOONAL FLOW AS AN UPPER LOW DIGS INTO THE PACIFIC NORTHWEST
FRIDAY INTO SATURDAY. THIS FLOW ENHANCE THE MOISTURE TRANSPORT INTO
THE REGION AND ALSO WILL INGEST TROPICAL VORTICITY FRAGMENTS FROM
THE SYSTEM CURRENTLY TROPICAL STORM KEVIN. THIS WILL BRING
INCREASING CHANCES FOR THUNDERSTORMS SATURDAY NIGHT INTO SUNDAY
AND WILL BE FOLLOWED BY ADDITIONAL CHANCES SUNDAY NIGHT AS A COLD
FRONT PASSES THROUGH THE STATE.
THIS WILL BE THE BEGINNING OF AN EVOLUTION TO A MORE FALL LIKE
PATTERN THAT OCCUR THROUGH THE PERIOD AS THE UPPER RIDGE IS
SUPPRESSES TO SOUTH AND EAST WHILE THE PACIFIC UPPER LOW LIFTS INTO
SOUTH CENTRAL CANADA AND WILL HELP DRIVE THE BOUNDARY INTO THE
STATE. THIS WILL PLACE THE MIDWEST IN A MORE PROGRESSIVE ZONAL FLOW
NEXT WEEK. THE BOUNDARY SUNDAY NIGHT WILL NOT BE ABLE TO DROP TOO
FAR SOUTH DUE TO THE ZONAL FLOW AND WILL LIFT BACK NORTH AS A WARM
FRONT TUESDAY. A STRONGER BOUNDARY WILL PUSH THROUGH TUESDAY NIGHT
INTO WEDNESDAY. EVEN COOLER AIR IS LIKELY TO ARRIVE JUST BEYOND THE
EXTENDED AND LIKELY SIGNALS THE END TO THE HOT AND HUMID WEATHER FOR
THE YEAR BEYOND THIS WEEKEND. WITH SUCH AN ACTIVE PATTERN AND STRONG
SYSTEMS...CAN NOT DISCOUNT A FEW SEVERE STORMS NEXT WEEK.
&&
.AVIATION...03/18Z
ISSUED AT 1229 PM CDT THU SEP 3 2015
WITH THE UPPER LEVEL RIDGE FIRMLY PLANTED ABOVE...ANYTHING OF
CONSEQUENCE WILL STAY TO THE WEST AND NORTHWEST OF THE TAF SITES.
MODEL SOUNDINGS HINT AT SOME LOCALIZED FOG TOMORROW MORNING...BUT
WITH HRRR DEPICTING OTHERWISE AND LITTLE CHANGE OVERNIGHT
OTHERWISE...HAVE KEPT FOG MENTIONS OUT FOR THIS ITERATION.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...AWB
LONG TERM...DONAVON
AVIATION...CURTIS
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
214 PM EDT THU SEP 3 2015
.UPDATE...
ISSUED AT 214 PM EDT THU SEP 3 2015
ISOLATED SHOWERS AND THUNDERSTORMS HAVE MANAGED TO DOT THE AREA
EVEN FURTHER SOUTHWEST. HAVE INCLUDED MOST OF THE AREA WITH AT
LEAST ISOLATED POPS FOR THE REST OF THE AFTERNOON BASED ON THE
RADAR TRENDS. FRESHENED UP THE HOURLY TEMPERATURES AND DEW POINTS
AS WELL TO JIVE BETTER WITH THE LATEST TRENDS IN OBSERVATIONS.
UPDATE ISSUED AT 1214 PM EDT THU SEP 3 2015
A FEW SHORT-LIVED SHOWERS MANAGED TO DEVELOP ACROSS PORTIONS OF
EASTERN PIKE COUNTY EARLIER...HOWEVER THESE HAVE SINCE DISSIPATED.
THE CU FIELD HAS BEEN MORE PREVALENT IN THE EAST SO FAR AND THE
LATEST HRRR MODEL OUTPUT CONTINUES TO SUGGEST THE BETTER POTENTIAL
FOR ANY ISOLATED ACTIVITY FOR THOSE LOCATIONS. DID GO AHEAD AND
ADD THUNDER FOR TODAY GIVEN THE MODERATELY STEEP LOW LEVEL LAPSE
RATES TO DEVELOP DURING PEAK HEATING. HIGHS TODAY LOOK ON
TARGET...WITH MOST LOCATIONS REACHING AROUND THE 90 DEGREE MARK.
UPDATE ISSUED AT 736 AM EDT THU SEP 3 2015
NO UPDATE THIS MORNING AS FORECAST IS ON TRACK. LOTS OF VALLEY FOG
OUT THERE SHOULD AND IT SHOULD BE BURNING OFF OVER THE NEXT FEW
HOURS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 257 AM EDT THU SEP 3 2015
NO PATTERN CHANGE EXPECTED THROUGH FRIDAY. THIS WILL MEAN A
CONTINUATION OF UNSEASONABLY WARM AND HUMID CONDITIONS THROUGH THE
END OF THE WEEK. A WEAK UPPER LEVEL TROUGH WILL CONTINUE TO
PRODUCE A MEAGER CHANCE OF A FEW AFTERNOON SHOWERS OR STORMS TODAY
AND AGAIN FRIDAY. HOWEVER...AS FAR AS TODAY GOES...HI RES MODELS
ARE INDICATING THAT WE MAY BE IN A HOLE WITH REGARDS TO CONVECTION
TODAY...KEEPING EVERYTHING FARTHER EAST. THERE DOES APPEAR TO BE A
WAVE IN THE FLOW TO OUR NORTHEAST...BUT REALLY SHOULD CLIP OUR
AREA. THUS...WILL DOWNPLAY PRECIPITATION CHANCES TODAY...JUST
GOING WITH A SLIGHT CHANCE OF A SHOWER IN THE FAR EAST/SOUTHEAST.
BETTER CHANCES FOR SHOWERS AND STORMS WILL COME IN ON FRIDAY
ACROSS SOUTHEAST KENTUCKY...BUT CHANCES WILL PROBABLY BE HIGHLY
DEPENDENT ON LOCAL BOUNDARIES AND PREVIOUS CONVECTION. THUS...WILL
GO WITH A GENERAL SLIGHT CHANCE OF THUNDER FOR FRIDAY AFTERNOON
ACROSS THE SOUTHEAST PORTION OF THE AREA. WILL KEEP HIGHS FAIRLY
CLOSE TO WHAT WE HAVE SEEN LATELY IN THE UPPER 80S TODAY AND
FRIDAY WITH LOWS IN THE 60S TONIGHT.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 346 AM EDT THU SEP 3 2015
THE UPPER LEVEL PATTERN THROUGH THE EXTENDED WILL CONTINUE TO
FEATURE AN UPPER LEVEL RIDGE OVER THE EASTERN CONUS. BY MONDAY
THOUGH...THE PATTERN BEGINS TO SHIFT AS THE RIDGE SHIFTS EAST AND
A STRONG TROUGH MOVES ACROSS THE UPPER PLAINS. THIS WILL BRING A
SIGNIFICANT SHIFT IN THE PATTERN. MODELS HAVE BEEN HINTING AT THIS
CHANGE FOR THE PAST FEW RUNS.
CLOSER TO THE SURFACE...UNDERNEATH THE RIDGE...THE AREA HAS BEEN
UNDER WARM AND UNSTABLE CONDITIONS EACH AFTERNOON WITH WEAK UPPER
LEVEL SUPPORT CAUSING SOME AFTERNOON CONVECTION EACH DAY. WARM AND
MOIST MAINLY WEAK SOUTHERLY FLOW CONTINUES THROUGH MONDAY WITH
MORNING FOG GIVING WAY TO SLIGHT TO LOW CHANCE POPS EACH
AFTERNOON. THIS DIURNAL TREND CONTINUES TILL MONDAY NIGHT INTO
TUESDAY WHEN THE MENTIONED UPPER TROUGH DRAGS A COLD FRONT THROUGH
THE AREA WITH A MORE PRONOUNCED SURFACE GRADIENT AND FORCING FOR
CONVECTION AND A BETTER CHANCE OF PRECIP NOT SEEN IN DAYS. AT
THIS TIME...MODELS ARE SLOWLY TRENDING WEAKER WITH THIS FRONT SO
HAVE GONE SLIGHTLY UNDER THE ALL MODEL BLEND SOLUTION BUT THIS
FEATURE STILL IS THE LARGEST CHANGE IN THE PATTERN YET. WENT WITH
LOW CHANCE POPS INTO WEDNESDAY AS THIS FEATURE MOVES THROUGH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 214 PM EDT THU SEP 3 2015
MAINLY VFR CONDITIONS WILL HOLD THROUGH 06Z...WITH THE EXCEPTION
OF WHERE ISOLATED CONVECTION CAN TRACK...WHICH WOULD LIKELY YIELD
SOME TEMPORARY MVFR OR WORSE CONDITIONS. GIVEN THE LIMITED AREAL
COVERAGE...HAVE ONLY INCLUDED VCSH OR VCTS EAST OF I-75.
CONVECTION WILL DIE OFF TOWARDS THIS EVENING...WITH FOG BECOMING
THE MAIN CONCERN ONCE AGAIN. HAVE MIRRORED VISIBILITIES AND
CEILINGS THAT WERE SEEN THIS MORNING AT THE TAF SITES...WITH THE
MAJORITY OF LOCATIONS LIKELY GOING DOWN HARD FOR A TIME BETWEEN 08
AND 12Z ONCE AGAIN. FOG WILL BURN OFF BETWEEN 12 AND 13Z...WITH A
REPEAT OF ISOLATED CONVECTION THREATENING BY FRIDAY AFTERNOON.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEOGERIAN
SHORT TERM...KAS
LONG TERM...SHALLENBERGER
AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1221 PM CDT THU SEP 3 2015
.UPDATE...
Issued at 1220 PM CDT THU SEP 3 2015
The AVIATION section has been updated for the 18Z TAF issuance.
&&
.SHORT TERM...(Today through Saturday)
Issued at 327 AM CDT THU SEP 3 2015
The 00Z models try to pinch the upper ridge from the east Friday
into Saturday, which leads to a little bit more pronounced surface
ridging by Saturday. The models are spitting out QPF just
northeast of our region, especially Friday night, but MOS PoPs are
mostly single digits. Won`t be surprised if we end up with some
PoPs Friday night or Saturday, but for now will just mention it
here and keep the forecast dry, and in line with neighboring
offices.
A literal handful of showers and one brief thunderstorm developed
across the forecast area yesterday afternoon. They were short-
lived, and with one exception, did not produce lightning. The 00Z
ARW and NMM WRF runs both generate some isolated convection across
the region this afternoon, and the latest HRRR shows some isolated
weak showers. With that support, will play the persistence card and
add isolated showers and storms to all but the far northwest and
western fringes of the area this afternoon. Will wait and see
what happens this afternoon before considering it for Friday
afternoon.
Temperatures climbed toward the warmer MAV/EC guidance yesterday
afternoon, so will continue to go that way with high temperatures
today and Friday. The 00Z MAV has 97 for Paducah Friday, but that
seems a bit spurious compared to surrounding MOS sites. Saturday
is a bit less clear cut, with the upper ridge weakening and
indications of a minor surge of surface high pressure over the
Evansville Tri State.
Stayed on the warm side of guidance Saturday over the Tri State,
but that does result in a couple of degrees of cooling from
Friday`s levels. Outside of the Tri State, Saturday could be just
as warm as Friday. The humidity is nothing like we had mid-summer,
but it could be just enough to allow heat indices to approach 100
in a few locations each afternoon.
Low temperatures tonight will be similar to this morning`s lows,
which are a bit lower than the consensus of guidance in most
locations. Lows Friday night may be closer to the consensus with
more wind expected.
.LONG TERM...(Saturday Night through Wednesday)
Issued at 327 AM CDT THU SEP 3 2015
The deterministic runs of the med range models have been somewhat
unstable of late, and the latest GFS 500 mb height spaghetti pattern
shows significantly increased chaos by Tue (Day 6), though the
latest GFS/ECMWF ensemble means appear quite similar overall. This
will affect confidence in the latter period forecast, regarding
impulses of energy in the nrn stream which may or may not produce a
secondary sfc front in our region.
Early in the extended period, the PAH forecast area will be affected
by an amplified srn stream pattern, with ridging aloft west of the
MS River and troffing over the Atlantic seaboard. Meanwhile, by Mon,
a cold front is progged to impinge on the ridge over our region.
There might be enough lift to produce a few showers and tstms in the
nwrn half of our region Mon afternoon, perhaps progressing a bit
farther sewd Mon night. The latest ECMWF appears to break down the
ridge more than the GFS by Tue, and is therefore more generous with
its QPF into Wed. For now, we downplayed PoPs a bit for Mon/Mon
night because of the lingering mid/upper ridge, then went generally
with the model initialization blend after that, which provided no
more than 40% PoPs for any 12 hour period. At this time, it appears
that model consensus and HPC point toward a bona fide sfc fropa at
the very end of the present Day 7 (Wed).
Expect above average temps through the extended period, slowly
decreasing by Day 7 to near seasonable levels.
&&
.AVIATION...
Issued at 1221 PM CDT THU SEP 3 2015
A few isolated showers or thunderstorms will be possible again across
the region this afternoon, but the coverage is expected to be too
sparse to mention in any of the TAFs. Otherwise, the only concern
to aviaton is MVFR fog potential at all terminals late tonight.
Like the last few nights, the fog, if it develops, will burn off
by around 14Z. Cu should then start developing soon after with
only isolated chances for convection.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS JACKSON KY
1214 PM EDT THU SEP 3 2015
.UPDATE...
ISSUED AT 1214 PM EDT THU SEP 3 2015
A FEW SHORT-LIVED SHOWERS MANAGED TO DEVELOP ACROSS PORTIONS OF
EASTERN PIKE COUNTY EARLIER...HOWEVER THESE HAVE SINCE DISSIPATED.
THE CU FIELD HAS BEEN MORE PREVALENT IN THE EAST SO FAR AND THE
LATEST HRRR MODEL OUTPUT CONTINUES TO SUGGEST THE BETTER POTENTIAL
FOR ANY ISOLATED ACTIVITY FOR THOSE LOCATIONS. DID GO AHEAD AND
ADD THUNDER FOR TODAY GIVEN THE MODERATELY STEEP LOW LEVEL LAPSE
RATES TO DEVELOP DURING PEAK HEATING. HIGHS TODAY LOOK ON
TARGET...WITH MOST LOCATIONS REACHING AROUND THE 90 DEGREE MARK.
UPDATE ISSUED AT 736 AM EDT THU SEP 3 2015
NO UPDATE THIS MORNING AS FORECAST IS ON TRACK. LOTS OF VALLEY FOG
OUT THERE SHOULD AND IT SHOULD BE BURNING OFF OVER THE NEXT FEW
HOURS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 257 AM EDT THU SEP 3 2015
NO PATTERN CHANGE EXPECTED THROUGH FRIDAY. THIS WILL MEAN A
CONTINUATION OF UNSEASONABLY WARM AND HUMID CONDITIONS THROUGH THE
END OF THE WEEK. A WEAK UPPER LEVEL TROUGH WILL CONTINUE TO
PRODUCE A MEAGER CHANCE OF A FEW AFTERNOON SHOWERS OR STORMS TODAY
AND AGAIN FRIDAY. HOWEVER...AS FAR AS TODAY GOES...HI RES MODELS
ARE INDICATING THAT WE MAY BE IN A HOLE WITH REGARDS TO CONVECTION
TODAY...KEEPING EVERYTHING FARTHER EAST. THERE DOES APPEAR TO BE A
WAVE IN THE FLOW TO OUR NORTHEAST...BUT REALLY SHOULD CLIP OUR
AREA. THUS...WILL DOWNPLAY PRECIPITATION CHANCES TODAY...JUST
GOING WITH A SLIGHT CHANCE OF A SHOWER IN THE FAR EAST/SOUTHEAST.
BETTER CHANCES FOR SHOWERS AND STORMS WILL COME IN ON FRIDAY
ACROSS SOUTHEAST KENTUCKY...BUT CHANCES WILL PROBABLY BE HIGHLY
DEPENDENT ON LOCAL BOUNDARIES AND PREVIOUS CONVECTION. THUS...WILL
GO WITH A GENERAL SLIGHT CHANCE OF THUNDER FOR FRIDAY AFTERNOON
ACROSS THE SOUTHEAST PORTION OF THE AREA. WILL KEEP HIGHS FAIRLY
CLOSE TO WHAT WE HAVE SEEN LATELY IN THE UPPER 80S TODAY AND
FRIDAY WITH LOWS IN THE 60S TONIGHT.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 346 AM EDT THU SEP 3 2015
THE UPPER LEVEL PATTERN THROUGH THE EXTENDED WILL CONTINUE TO
FEATURE AN UPPER LEVEL RIDGE OVER THE EASTERN CONUS. BY MONDAY
THOUGH...THE PATTERN BEGINS TO SHIFT AS THE RIDGE SHIFTS EAST AND
A STRONG TROUGH MOVES ACROSS THE UPPER PLAINS. THIS WILL BRING A
SIGNIFICANT SHIFT IN THE PATTERN. MODELS HAVE BEEN HINTING AT THIS
CHANGE FOR THE PAST FEW RUNS.
CLOSER TO THE SURFACE...UNDERNEATH THE RIDGE...THE AREA HAS BEEN
UNDER WARM AND UNSTABLE CONDITIONS EACH AFTERNOON WITH WEAK UPPER
LEVEL SUPPORT CAUSING SOME AFTERNOON CONVECTION EACH DAY. WARM AND
MOIST MAINLY WEAK SOUTHERLY FLOW CONTINUES THROUGH MONDAY WITH
MORNING FOG GIVING WAY TO SLIGHT TO LOW CHANCE POPS EACH
AFTERNOON. THIS DIURNAL TREND CONTINUES TILL MONDAY NIGHT INTO
TUESDAY WHEN THE MENTIONED UPPER TROUGH DRAGS A COLD FRONT THROUGH
THE AREA WITH A MORE PRONOUNCED SURFACE GRADIENT AND FORCING FOR
CONVECTION AND A BETTER CHANCE OF PRECIP NOT SEEN IN DAYS. AT
THIS TIME...MODELS ARE SLOWLY TRENDING WEAKER WITH THIS FRONT SO
HAVE GONE SLIGHTLY UNDER THE ALL MODEL BLEND SOLUTION BUT THIS
FEATURE STILL IS THE LARGEST CHANGE IN THE PATTERN YET. WENT WITH
LOW CHANCE POPS INTO WEDNESDAY AS THIS FEATURE MOVES THROUGH.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 736 AM EDT THU SEP 3 2015
ANOTHER TYPICAL EASTERN KENTUCKY MORNING WITH MORE VALLEY FOG.
THIS FOG WILL BURN OFF OVER THE NEXT HOUR TO TWO HOURS. THIS WILL
BRING A RETURN TO VFR CONDITIONS BY MID MORNING. SOME SCATTERED
CU WILL DEVELOP TOMORROW AFTERNOON...BUT CONDITIONS SHOULD STAY
VFR THROUGH THE EVENING. ANOTHER ROUND OF VALLEY FOG IS EXPECTED
LATE TONIGHT AND WILL BRING VISIBILITIES AND CEILINGS DOWN AT THE
TAF SITES ONCE MORE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEOGERIAN
SHORT TERM...KAS
LONG TERM...SHALLENBERGER
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
357 PM EDT THU SEP 3 2015
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 356 PM EDT THU SEP 3 2015
WV IMAGERY AND RAP ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH ALONG
THE WEST COAST AND A DOWNSTREAM RIDGE FROM TEH SRN PLAINS INTO THE
UPPER MS VALLEY. A SHORTWAVE TROUGH OVER LOWER MI...ON THE FORWARD
FLANK OF THE RIDGE...WAS VERY SLOWLY EDING TO THE SE. AT THE SFC...A
RIDGE EXTENDED FROM QUEBEC AND NRN ONTARIO INTO LAKE SUPERIOR
RESULTING IN LIGHT E TO NE FLOW THROUGH UPPER MI. VIS LOOP SHOWED
MOSTLY SUNNY SKIES ACROSS THE NORTH WITH SCT-BKN CU INLAND CNTRL.
TONIGHT...WITH THE LOSS OF DAYTIME HEATING...THE CU WILL FADE
LEAVING MOSTLY CLEAR SKIES. HOWEVER...SOME MID CLOUS AROUND THD
PERSISTENT LOW MAY MOVE BACK INTO THE SE. GIVEN DEWPOINTS IN LOWER
60S...RADIATIONAL COOLING SHOULD DROP MINS TO AROUND 60...COOLEST
OVER THE INLAND WEST HALF. SO...EXPECT AREAS OF FOG ARE LIKELY TO
DEVELOP...ESPECIALLY CNTRL.
FRI...ALTHOUGH THE LOWER MI MID LEVEL LOW SHOULD STILL
LINGER...UPPER MI WILL REMAIN UNDER THE INFLUENCE OF THE SFC RIDGE
WITH MOSTLY SUNNY SKIES AFTER THE MORNING FOG OR LOW CLOUDS BURN
OFF. WITH 850 MB TEMPS AROUND 15C...TEMPS SHOULD CLIMB TO AROUND
80...WITH LOWER READINGS ALONG THE GREAT LAKES.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 317 PM EDT THU SEP 3 2015
MAINLY FOCUSED ON SHOWER AND THUNDERSTORM COVERAGE/INTENSITY SAT
NIGHT INTO MONDAY AND ON CONTINUED HOT/HUMID CONDITIONS SAT AND SUN.
FRI NIGHT LOOKS DRY FOR MOST PART...BUT THERE IS A SLIGHT CHANCE OF
SHOWERS AND THUNDERSTORMS OVER THE W A SHORTWAVE ENERGY MOVES W OF
THE CWA IN THE SW FLOW ALOFT. A SIMILAR SETUP ON SAT...BUT GREATER
CHANCES OF PRECIP OVER THE W. COULD SEE SOME STRONG TO POSSIBLY
SEVERE STORMS...IF CONVECTION DOES DEVELOP...DUE TO 1000-2000 J/KG
OF MUCAPE. 0-6KM SHEAR WILL BE ON THE WEAK SIDE SAT AT ONLY AROUND
20KTS...WHICH LIMITS ORGANIZED SEVERE POTENTIAL.
THE 12Z/03 GFS IS AN OUTLIER FOR SAT NIGHT IN SHOWING PRECIP OVER
THE CENTRAL CWA. THINK THAT MOST OF THE AREA WILL STAY DRY SAT
NIGHT...WITH THE W POSSIBLY SEEING SOME CONVECTION. PRECIP LOOKS TO
STAY OVER THE W HALF ON SUN AS A STRONGER SHORTWAVE MOVES TO THE W.
WIND SHEAR WILL BE GREATER SUN...WITH 0-6KM BULK VALUES AROUND
30KTS...BUT MUCAPES WILL ONLY BE 1000-1500J/KG. TEMPS WILL BE
WARMEST ON SUN AS 850MB TEMPS WILL BE 20-22C...PROMOTING WARMEST
TEMPS AROUND 90 IN DOWNSLOPING AREAS OF NCENTRAL UPPER MI NEAR LAKE
SUPERIOR.
THE COLD FRONT FROM A LOW PRESSURE SYSTEM MOVING ACROSS SRN CANADA
WILL PASS THROUGH THE AREA SUN NIGHT INTO MON MORNING...WHICH WILL
MEAN LIMITED INSTABILITY AND MINIMAL SEVERE POTENTIAL. COVERAGE OF
CONVECTION LOOKS GOOD...WITH MOST LOCATIONS SEEING SOME PRECIP.
MON WILL SEE CLEARING SKIES AND PRECIP EXITING E. THE AIRMASS WILL
BECOME COOLER AND DRIER...BUT 850MB TEMPS ONLY DROP INTO THE MID
TEENS C BY LATE MON. THIS SHOULD RESULT IN HIGHS FROM THE MID 70S TO
LOW 80S.
LOTS OF UNCERTAINTY MID TO LATE NEXT WEEK AS DETAILS OF A TROUGH
DROPPING INTO THE REGION ARE HARD TO PIN DOWN. DOES LOOK COOLER WITH
AT LEAST A SLIGHT CHANCE OF PRECIP.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 137 PM EDT THU SEP 3 2015
EXPECT VFR CONDITIONS THROUGH THIS EVENING. CLEAR SKIES AND LIGHT
WINDS WILL LIKELY CAUSE IFR CONDITIONS ONCE AGAIN LATER TONIGHT INTO
FRIDAY MORNING...MAINLY AT KIWD/KSAW WHILE MVFR VSBY IS EXPECTED AT
KCMX.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 356 PM EDT THU SEP 3 2015
AREAS OF FOG PERSISTED ACROSS THE WESTERN THIRD OF THE LAKE AND IS
EXPECTED TO LINGER INTO FRI WITH NE FLOW CONTINUING.
OTHERWISE...NORTHEAST WINDS OF 10-15KT WILL CONTINUE TODAY WITH 1-3
FT WAVES ACROSS THE WEST. THE NEXT CHANCE FOR WINDS GREATER THAN
20KT WILL BE SUNDAY INTO MONDAY AS THE NEXT SYSTEM APPROACHES FROM
THE WEST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
317 PM EDT THU SEP 3 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 412 AM EDT THU SEP 3 2015
THE RAIN OVER THE SOUTHERN AND EASTERN PART OF THE FORECAST AREA
FINALLY SEEMS TO BE MOVING OUT OF THE AREA AS THE UPPER SHORT WAVE
MOVES EAST. THE BIG PROBLEM THIS MORNING IS ACTUALLY DENSE FOG
ACROSS THE WESTERN PART OF THE FORECAST AREA WHERE IT HAS CLEARED
OUT WITH SUFFICIENT LOW LEVEL MOISTURE FROM RAINFALL OVER THE PAST
24 HR. MOST OF THE WESTERN TIER OF COUNTIES HAVE VSBYS LESS THAN ONE
QUARTER OF A MILE AND AS SUCH HAVE OPTED TO GO WITH A DENSE FOG
ADVISORY FOR THIS AREA UNTIL 14Z.
OTHERWISE...AS THE UPPER SHORT WAVE SLOWLY MOVES EAST THIS
MORNING...EXPECT ANY REMAINING SHOWERS TO MOVE OUT OF THE AREA AS
WELL. THE RAP SUGGESTS THAT CYCLONIC FLOW WILL PERSIST THROUGH THE
DAY ACROSS THE EAST. THIS COMBINED WITH LAKE BREEZE CONVERGENCE
ACROSS THE EAST IMPLIES AT LEAST A SLIGHT CHANCE OF SHOWERS THIS
AFTERNOON ACROSS THE FAR EAST. NOT TOO EXCITED ABOUT THUNDERSTORM
CHANCES AS LOCAL RESEARCH SUGGESTS VERY MIMINAL THUNDERSTORM
DEVELOPMENT WITH NORTHERLY MID LEVEL FLOW. ACROSS THE REMAINDER OF
THE AREA...MINIMAL MLCAPE VALUES OF LESS THAN 300 J/KG PER THE
RAP...DRY AIR ASSOCIATED WITH THE HIGH PRES AND BUILDING HEIGHTS
SHOULD PRECLUDE ANY SHOWER/THUNDERSTORM DEVELOPMENT. DESPITE THE
NORTH-NORTHEAST FLOW...IT WILL STILL REMAIN MILD AND RATHER STICKY
WITH HIGHS IN THE UPPER 70S/LOWER 80S...STILL ABOVE NORMAL FOR EARLY
SEPTEMBER.
WITH HIGH PRESSURE IN CONTROL...IT SHOULD BE A QUIET NIGHT TONIGHT.
CANNOT RULE OUT MORE FOG DEVELOPMENT ACROSS THE INTERIOR WITH LIGHT
WINDS AND CLEAR SKIES. TEMPS SHOULD DROP INTO THE UPPER 50S/LOWER
60S.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 317 PM EDT THU SEP 3 2015
MAINLY FOCUSED ON SHOWER AND THUNDERSTORM COVERAGE/INTENSITY SAT
NIGHT INTO MONDAY AND ON CONTINUED HOT/HUMID CONDITIONS SAT AND SUN.
FRI NIGHT LOOKS DRY FOR MOST PART...BUT THERE IS A SLIGHT CHANCE OF
SHOWERS AND THUNDERSTORMS OVER THE W A SHORTWAVE ENERGY MOVES W OF
THE CWA IN THE SW FLOW ALOFT. A SIMILAR SETUP ON SAT...BUT GREATER
CHANCES OF PRECIP OVER THE W. COULD SEE SOME STRONG TO POSSIBLY
SEVERE STORMS...IF CONVECTION DOES DEVELOP...DUE TO 1000-2000 J/KG
OF MUCAPE. 0-6KM SHEAR WILL BE ON THE WEAK SIDE SAT AT ONLY AROUND
20KTS...WHICH LIMITS ORGANIZED SEVERE POTENTIAL.
THE 12Z/03 GFS IS AN OUTLIER FOR SAT NIGHT IN SHOWING PRECIP OVER
THE CENTRAL CWA. THINK THAT MOST OF THE AREA WILL STAY DRY SAT
NIGHT...WITH THE W POSSIBLY SEEING SOME CONVECTION. PRECIP LOOKS TO
STAY OVER THE W HALF ON SUN AS A STRONGER SHORTWAVE MOVES TO THE W.
WIND SHEAR WILL BE GREATER SUN...WITH 0-6KM BULK VALUES AROUND
30KTS...BUT MUCAPES WILL ONLY BE 1000-1500J/KG. TEMPS WILL BE
WARMEST ON SUN AS 850MB TEMPS WILL BE 20-22C...PROMOTING WARMEST
TEMPS AROUND 90 IN DOWNSLOPING AREAS OF NCENTRAL UPPER MI NEAR LAKE
SUPERIOR.
THE COLD FRONT FROM A LOW PRESSURE SYSTEM MOVING ACROSS SRN CANADA
WILL PASS THROUGH THE AREA SUN NIGHT INTO MON MORNING...WHICH WILL
MEAN LIMITED INSTABILITY AND MINIMAL SEVERE POTENTIAL. COVERAGE OF
CONVECTION LOOKS GOOD...WITH MOST LOCATIONS SEEING SOME PRECIP.
MON WILL SEE CLEARING SKIES AND PRECIP EXITING E. THE AIRMASS WILL
BECOME COOLER AND DRIER...BUT 850MB TEMPS ONLY DROP INTO THE MID
TEENS C BY LATE MON. THIS SHOULD RESULT IN HIGHS FROM THE MID 70S TO
LOW 80S.
LOTS OF UNCERTAINTY MID TO LATE NEXT WEEK AS DETAILS OF A TROUGH
DROPPING INTO THE REGION ARE HARD TO PIN DOWN. DOES LOOK COOLER WITH
AT LEAST A SLIGHT CHANCE OF PRECIP.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 137 PM EDT THU SEP 3 2015
EXPECT VFR CONDITIONS THROUGH THIS EVENING. CLEAR SKIES AND LIGHT
WINDS WILL LIKELY CAUSE IFR CONDITIONS ONCE AGAIN LATER TONIGHT INTO
FRIDAY MORNING...MAINLY AT KIWD/KSAW WHILE MVFR VSBY IS EXPECTED AT
KCMX.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 412 AM EDT THU SEP 3 2015
DENSE FOG HAS DEVELOPED ACROSS THE WESTERN HALF OF THE
LAKE...ESPECIALLY OVER AREAS THAT SAW RAIN YESTERDAY. AS SUCH...HAVE
ISSUED A DENSE FOG ADVY FOR THE ENTIRE WEST HALF OF THE LAKE THROUGH
EARLY THIS AFTERNOON. OTHERWISE...NORTHEAST WINDS OF 10-15KT WILL
CONTINUE TODAY WITH 1-3 FT WAVES ACROSS THE WEST. THE NEXT CHANCE
FOR WINDS GREATER THAN 20KT WILL BE SUNDAY INTO MONDAY AS THE NEXT
SYSTEM APPROACHES FROM THE WEST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...MRD
LONG TERM...TITUS
AVIATION...JLB
MARINE...MRD
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
217 PM EDT THU SEP 3 2015
.AVIATION...
DEEPER MOISTURE AXIS AND THERMAL ADVECTION SUPPORT OCCURRING ON
THE SOUTHEAST FORWARD FLANK OF MCS IS LEADING TO WIDESPREAD RAIN
AND THUNDERSTORM ACTIVITY THIS AFTERNOON. CONFIDENCE IS HIGH IN
CONTINUED ACTIVITY FOR THE NEXT 3-6 HOURS WITH INCREASING
UNCERTAINTY FOR TONIGHT. A STALLING OUT OF PARENT FORCING ALOFT DOES
SUPPORT THE POTENTIAL THAT SHOWER AND THUNDERSTORMS COULD AFFECT
THE AREA THROUGH MUCH OF TONIGHT. HIGH LOW LEVEL MOISTURE CONTENT
AND WET SOIL CONDITIONS SUPPORTS FOG DEVELOPMENT LATE.
POSSIBILITY EXISTS FOR ONE OR MORE TERMINALS TO DROP INTO LIFR
DURING THE EARLY MORNING PERIOD...CONFIDENCE TOO LOW YET TO
INCLUDE BUT WILL HIGHLIGHT WITH IFR VSBY RESTRICTIONS.
FOR DTW...GREATEST POTENTIAL FOR THUNDERSTORMS CENTERED WITHIN THE
18Z-00Z WINDOW...UNCERTAINTY IS HIGH WITH REGARDS TO THUNDERSTORM
POTENTIAL 00-12Z.
//DTW THRESHOLD PROBABILITIES...
* MEDIUM FOR CIG AOB 5KFT THIS AFTERNOON AND EVENING
* HIGH FOR THUNDERSTORMS THIS AFTERNOON AND EVENING
&&
.PREV DISCUSSION...ISSUED 1239 PM EDT THU SEP 3 2015
UPDATE...
DUAL SHORTWAVES OVER THE WESTERN AND CENTRAL GREAT LAKES WILL
REMAIN THE SOLE FORCING MECHANISMS THROUGH THE NEXT 18 HOURS. THE
SMALL MCS IMPACTING LOWER MICHIGAN IS TIED TO THE FIRST LOWER
COLUMN PV ANOMALY...THE SECOND IS THE SHORTWAVE CIRCULATION THAT
IS NOW DROPPING INTO THE BACKSIDE OF THE GEOPOTENTIAL HEIGHT
WEAKNESS OVER FAR NORTHERN WISCONSIN. AT THE BIG PICTURE...LOWER
DELTA X SOLUTIONS/GLOBAL MODELS SUGGEST A PHASING OF THE TWO
SHORTWAVES AND A SUBSEQUENT STALLING OF THE COMBINED PV ANOMALY
LATE THIS AFTERNOON AND TONIGHT.
THE MCS THAT HAS BEEN PUSHING ACROSS THE NORTHERN CWA CONTINUES TO
MAKE SOME PROGRESS EASTWARD. A LINEAR EXTRAPOLATION OF REGIONAL Z
MOSAIC CONTINUES TO SUPPORT SOME SLIGHT SOUTHWARD DRIFT WITH TIME
ON THE TRACK OF THE MCS. THIS SOUTHWARD DRIFT SHOULD AT LEAST BE
PARTIALLY SUPPORTIVE BY ADDITIONAL OUTFLOW DEVELOPMENT ALONG THE
SOUTHERN FLANK. THERE HAS BEEN SOME MODEST...CONTINUED DEVELOPMENT
DURING THE PAST FEW HOURS. NWP GUIDANCE WITH A BULLISH HRRR AND
BOTH NAM/ECMWF SUPPORT BRING ADDITIONAL CONVECTIVE DEVELOPMENT FOR
ALL OF SOUTHEASTERN MICHIGAN DURING THE AFTERNOON HOURS. GIVEN THE
LACK OF AN AGGRESSIVE SOUTHERN PROGRESSION TO THE
STRATUS/CIRRUS/CU DECK EXPECTATIONS ARE FOR THE
INSTABILITY/BUOYANCY GRADIENT TO REMAIN DRAPED THROUGH FAR
SOUTHERN SECTIONS OF THE CWA. THE FORECAST IS SKEWED ON THE
AGGRESSIVE SIDE WITH RESPECT TO RAIN AND THUNDERSTORM ACTIVITY
THIS LATER THIS AFTERNOON AND EVENING. THERE DOES REMAIN A SLIVER
OF DOUBT THAT THUNDERSTORMS WILL FILL IN COMPLETELY ACROSS FAR
SOUTHERN LOWER MICHIGAN AND IMPACT DETROIT METRO DIRECTLY. STORM
BEHAVIOR TODAY IS EXPECTED TO REMAIN MORE OF A PULSE TYPE NATURE
WITH PERHAPS SOME EMBEDDED LINE TYPE FEATURES. THEREFORE...A LOW
END DAMAGING WIND GUST THREAT EXISTS THIS AFTERNOON AND WILL
PERHAPS BE A CIRCUMSTANCE OF CONSTRUCTIVE CELL MERGERS OR
PRECIPITATION LOADING EFFECTS.
A CONCERNING POTENTIAL WILL CONTINUE TO BE A HEAVY RAINFALL
THREAT...ESPECIALLY UNDER THE DIRECTION OF ADVERTISED PHASING AND
STALLING OUT OF PV MAX OVERHEAD. PWATS ARE AT APPROXIMATELY 1.8
INCHES. SOME SAMPLED RAINFALL RATES EARLIER OFF OF RADAR BASED
PRECIPITATION PRODUCT SUGGESTS 1.25 INCHES OF RAINFALL IS
POSSIBLE IN ROUGHLY 40 MINUTES. WILL BE MONITORING ACTIVITY THIS
AFTERNOON FOR ANY TRAINING OR STATIONARY BEHAVIOR OF THUNDERSTORMS.
PREV DISCUSSION...ISSUED 333 AM EDT THU SEP 3 2015
SHORT TERM...TODAY AND TONIGHT
ATTENTION OVER THE NEXT 24 TO 36 HOURS CENTERS ON THE INBOUND SLOWLY
MOVING MID LEVEL WAVE CURRENTLY CENTERED ACROSS THE LAKE MICHIGAN
CORRIDOR. LITTLE VARIATION IN THE UNDERLYING LOW LEVEL
THERMODYNAMIC PROFILE HEADING INTO TODAY...WITH SE MICHIGAN FIRMLY
ENTRENCHED WITHIN A MOISTURE RICH LOW LEVEL ENVIRONMENT /LOWER 70S
DEWPOINTS/. AS NOTED YESTERDAY...THIS WILL AGAIN TRANSLATE INTO
SUBSTANTIAL LOW LEVEL INSTABILITY (2500+ J/KG SBCAPE) WITHIN A VERY
STEEP LAPSE RATE ENVIRONMENT. INCREASING DPVA AND AN ACCOMPANYING POCKET
OF COOLER MID LEVEL TEMPERATURES WILL CONTRIBUTE AN ADDITIONAL
COMPONENT OF DESTABILIZATION AND MORE FOCUSED ASCENT FOR TODAY.
THIS ENVIRONMENT SEEMS CONDUCIVE FOR A MORE SIZABLE EXPANSION IN
CONVECTIVE COVERAGE LOCALLY...AND WORTHY OF A NUDGE UPWARD IN
POPS...PARTICULARLY FOR THE AFTERNOON/EVENING PERIODS. THE HIGH
MOISTURE CONTENT AND CORRESPONDING POTENTIAL FOR SIGNIFICANT
PRECIPITATION LOADING WITHIN THE DEEPEST CONVECTIVE CELLS WILL
AGAIN PRESENT THE POTENTIAL FOR STRONGER WIND GUSTS...WITH AT
LEAST AN OUTSIDE POSSIBILITY THAT AN ISOLATED STORM OR TWO CAN
GENERATE A PEAK GUST NEARING SEVERE LIMITS. SOLID HEAVY RAINFALL
THREAT GIVEN LIKELY LIMITED STORM MOTION WITHIN THIS HIGH CAPE
ENVIRONMENT. HIGHS TODAY A TOUCH LOWER WITH THE ENSUING EXPANSION
IN CONVECTION/CLOUD COVER LIKELY UNDERCUTTING THE HEATING
POTENTIAL SLIGHTLY. READINGS TOPPING OUT IN THE LOWER AND MIDDLE
80S...HEAT INDICES APPROACHING 90.
GRADUAL COOLING VIA DIABATIC PROCESSES AND ANY OUTFLOW WILL FAVOR A
DIMINISHING TREND TO EXISTING CONVECTIVE ACTIVITY BY EARLY TONIGHT.
HOWEVER THE UNDERLYING ENVIRONMENT WILL STILL REMAIN FAVORABLE FOR
ADDITIONAL ISOLATED-SCATTERED DEVELOPMENT THROUGHOUT THE NIGHT.
INCREASING POTENTIAL FOR FOG OVERNIGHT...MOIST NEAR SURFACE
ENVIRONMENT AUGMENTED BY THE RAINFALL AND WEAK GRADIENT. A CORRIDOR
OF DENSE FOG FOR THE EARLY MORNING COMMUTE NOT OUT OF THE QUESTION.
LONG TERM...
MULTIPLE UPPER WAVES UPSTREAM OVER UPPER MISSISSIPPI RIVER VALLEY
THIS MORNING...WHICH WILL CONSOLIDATE OVER THE WESTERN/CENTRAL GREAT
LAKES TONIGHT INTO FRIDAY...BUT THE EXACT POSITION OF THE DEVELOPED
MID LEVEL CIRCULATION/500 MB LOW IS QUESTION...AS 00Z NAM/GFS ARE
INDICATING A FARTHER SOUTH/WEST SOLUTION...NEAR CHICAGO...WHILE
EURO/CANADIAN REMAIN STEADFAST WITH 500 MB LOW FARTHER NORTH/EAST
OVER NORTHERN LOWER MICHIGAN. EITHER WAY...CHANCE POPS STILL SEEM
WARRANTED...EVEN WITH THE STRENGTHENING HIGH PRESSURE OVER EASTERN
CANADA (1025 MB)...AS THE LOW LEVEL SOUTHEAST/EAST FLOW WILL
INCREASE A BIT...BUT THERE ACTUALLY LOOKS TO BE MODEST MOISTURE
ADVECTION FROM WESTERN PA/LAKE ERIE. MLCAPES PROGGED TO INCREASE
INTO THE 500 TO 1500 J/KG RANGE DURING FRIDAY...PER 00Z EURO.
STILL LINGERING UPPER LEVEL TROUGHINESS ON SATURDAY WITH MLCAPES
RISING INTO THE 1000-2000 J/KG RANGE TO SUPPORT LOW CHANCE POPS.
UPPER LEVEL RIDGE BUILDING OUT AHEAD OF STRONG GREAT BASIN 500 MB
LOW ON SATURDAY SHOULD EXERT A BIGGER INFLUENCE FOR THE SECOND HALF
OF THE WEEKEND...ALLOWING FOR TEMPERATURES TO HEAT UP ONCE
AGAIN...WITH 90 DEGREES LIKELY ON SUNDAY...AS SOUTH-SOUTHWEST FLOW
INCREASES OUT AHEAD OF NEXT COLD FRONT...WITH 850 MB TEMPS PROGGED
TO BE IN THE 18-19 C RANGE. UPPER LEVEL RIDGE AXIS ARRIVING SUNDAY
AFTERNOON IS EXPECTED TO PROVIDE ENOUGH MID LEVEL WARMING/SUBSIDENT
BACKDROP TO SQUELCH POTENTIAL CONVECTION. THE SAME CAN NOT BE SAID
FOR EARLY NEXT WEAK AS SOLID HEIGHT FALLS/MOISTURE PLUME/AXIS (PW
VALUES OF 2 INCHES) AND COLD FRONT TRACKS THROUGH THE GREAT LAKES
REGION.
MARINE...
STRENGTHENING HIGH PRESSURE OVER EASTERN CANADA WILL PROMOTE LIGHT
EASTERLY FLOW AS WE HEAD INTO FRIDAY. UPPER LEVEL DISTURBANCE WILL
RESULT IN SCATTERED SHOWERS AND THUNDERSTORMS THROUGH FRIDAY...WITH
A LOW CHANCE ON SATURDAY. WINDS WILL SHIFT TO THE SOUTH OVER THE
WEEKEND...BUT REMAIN LIGHT...AS VERY WARM AIR STREAMS INTO THE
REGION.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....CB
UPDATE.......CB
SHORT TERM...MR
LONG TERM....SF
MARINE.......SF
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
137 PM EDT THU SEP 3 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 412 AM EDT THU SEP 3 2015
THE RAIN OVER THE SOUTHERN AND EASTERN PART OF THE FORECAST AREA
FINALLY SEEMS TO BE MOVING OUT OF THE AREA AS THE UPPER SHORT WAVE
MOVES EAST. THE BIG PROBLEM THIS MORNING IS ACTUALLY DENSE FOG
ACROSS THE WESTERN PART OF THE FORECAST AREA WHERE IT HAS CLEARED
OUT WITH SUFFICIENT LOW LEVEL MOISTURE FROM RAINFALL OVER THE PAST
24 HR. MOST OF THE WESTERN TIER OF COUNTIES HAVE VSBYS LESS THAN ONE
QUARTER OF A MILE AND AS SUCH HAVE OPTED TO GO WITH A DENSE FOG
ADVISORY FOR THIS AREA UNTIL 14Z.
OTHERWISE...AS THE UPPER SHORT WAVE SLOWLY MOVES EAST THIS
MORNING...EXPECT ANY REMAINING SHOWERS TO MOVE OUT OF THE AREA AS
WELL. THE RAP SUGGESTS THAT CYCLONIC FLOW WILL PERSIST THROUGH THE
DAY ACROSS THE EAST. THIS COMBINED WITH LAKE BREEZE CONVERGENCE
ACROSS THE EAST IMPLIES AT LEAST A SLIGHT CHANCE OF SHOWERS THIS
AFTERNOON ACROSS THE FAR EAST. NOT TOO EXCITED ABOUT THUNDERSTORM
CHANCES AS LOCAL RESEARCH SUGGESTS VERY MIMINAL THUNDERSTORM
DEVELOPMENT WITH NORTHERLY MID LEVEL FLOW. ACROSS THE REMAINDER OF
THE AREA...MINIMAL MLCAPE VALUES OF LESS THAN 300 J/KG PER THE
RAP...DRY AIR ASSOCIATED WITH THE HIGH PRES AND BUILDING HEIGHTS
SHOULD PRECLUDE ANY SHOWER/THUNDERSTORM DEVELOPMENT. DESPITE THE
NORTH-NORTHEAST FLOW...IT WILL STILL REMAIN MILD AND RATHER STICKY
WITH HIGHS IN THE UPPER 70S/LOWER 80S...STILL ABOVE NORMAL FOR EARLY
SEPTEMBER.
WITH HIGH PRESSURE IN CONTROL...IT SHOULD BE A QUIET NIGHT TONIGHT.
CANNOT RULE OUT MORE FOG DEVELOPMENT ACROSS THE INTERIOR WITH LIGHT
WINDS AND CLEAR SKIES. TEMPS SHOULD DROP INTO THE UPPER 50S/LOWER
60S.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 452 AM EDT THU SEP 3 2015
PRIME CONCERNS IN LONG TERM INCLUDE EXTENT/STRENGTH OF SHRA/TSRA
THIS WEEKEND INTO LABOR DAY AND MAX TEMPS. FOG WILL ALSO BE ISSUE
AT TIMES WITH HUMID AIRMASS PERSISTING UNTIL COLD FRONT ARRIVES BY
LABOR DAY.
UPPER RIDGE BUILDS BACK OVER UPPER GREAT LAKES ON FRIDAY. REMNANT OF
SHORTWAVE THAT IS MOVING THROUGH ATTM MEANDERS OVER LOWER MICHIGAN
AND MAY DRIFT TOWARD EAST CWA BY EVENING. GFS/NAM SOUNDINGS SEEM TOO
DRY FOR SHRA/TSRA WITH GENERAL EAST SFC WINDS COMING OUT OF HIGH
OVER QUEBEC. SLIGHTLY DRIER TOO WITH UPR 50S TO LOW 60S DWPNTS
INSTEAD OF UPR 60S-NEAR 70. COULD BE FOG AROUND TO START DAY BUT
THAT SHOULD GIVE WAY TO MOSTLY SUNNY SKIES BY LATE MORNING. TEMPS
HELD DOWN BY OVERALL FLOW OFF THE GREAT LAKES AND COOLER TEMPS
ALOFT. EXPECT MID 80S INTERIOR WEST AND UPR 70S NEAR 80 OVER REST OF
CWA.
EDGE OF UPPER RIDGE DRAWS CLOSE ENOUGH FRIDAY NIGHT INTO SATURDAY TO
BRING SHRA/TSRA POSSIBILITY BACK TO THE AREA...ADVECTING IN FM
NORTHERN PLAINS WITH SW MEAN LAYER H85-H3 WINDS. EDGE OF MUCAPE OVER
1000J/KG AS CLOSE AS NORTHERN MN AND NORTHERN WI. ECMWF AND GFS ALSO
BOTH SHOWING SHORTWAVE CURRENTLY OVER FOUR CORNERS TRACKING OVER
NORTHERN MN AND LK SUPERIOR BY 12Z SATURDAY. INCREASING H85 JET
RAMPS UP MOISTURE ADVECTION OVER MN SO HAVE PUT CHANCE POPS OVER
WESTERN LK SUPERIOR ON FRIDAY NIGHT AND SPREAD THEM INTO FAR WEST
CWA ON SATURDAY AS THERE MAY BE GREATER CHANCE OF SHRA/TSRA IN VCNTY
OF THE SHORTWAVE AND GIVEN THE HIGHER MUCAPES. MLCAPES ALSO PUSH UP
TOWARD 1000J/KG DURING AFTN SO THERE MAY BE ADDITIONAL SHRA/TSRA TRY
TO FORM DUE TO DAYTIME HEATING AND POSSIBLY AFFECTS FM THE
SHORTWAVE. PROBABLY WILL BE SOME FOG AROUND TO START DAY AGAIN. SE
WINDS ADDING MOISTURE OFF LK MICHIGAN AND RADIATIONAL COOLING FRIDAY
NIGHT SHOULD LEAD TO BEST BET FOR FOG OVER INTERIOR CNTRL AND NEAR
LK MICHIGAN. ONCE FOG EVADES...PARTLY SUNNY SKIES WILL ALLOW TEMPS
TO WARM QUITE A BIT OVER FRIDAY. H85 TEMPS PUSHING 19-20C BY AFTN
AND MORE OF A SOUTH WIND COMPARED TO FRIDAY POINT TO MID-UPR 80S FOR
MOST WITH A FEW 90 DEGREE READINGS POSSIBLE INTERIOR WEST AND NEAR
LK SUPERIOR WITH DOWNSLOPING WINDS.
STRONGER SHORTWAVE LIFTS OVER UPPER MISSISSIPPI RIVER VALLEY SAT
NIGHT IN SW FLOW ALOFT. AT SFC...LOW PRESSURE SYSTEM WILL BE
DEVELOPING OVER HIGH PLAINS WHILE TROUGHING EXTENDS ACROSS NORTHERN
PLAINS AND TO NORTHWEST ONTARIO. SOUTH WINDS AHEAD OF TROUGH SHOULD
LEAD TO WARM/MUGGY NIGHT OVER UPR MICHIGAN. MUCAPES REMAIN HIGH AT
1000-2000J/KG FM NORTHERN PLAINS ACROSS UPPER GREAT LAKES. IF
SHORTWAVE TRACKS CLOSE ENOUGH...COULD SEE SHRA/TSRA PUSH OVER WEST
HALF OF CWA AT LEAST WITH H85-H3 WINDS FM THE WSW. UNLIKE FRIDAY
NIGHT WITH SIMILAR SETUP...SHEAR IS FORECAST TO BE MUCH STRONGER AS
1-6KM SHEAR VALUES ARE 30-40 KTS. LOW-LEVEL JET AT H85 OVER 40 KTS
IS AIMED TOWARD UPPER MISSISSIPPI RIVER VALLEY AND AT LEAST WESTERN
FRINGE OF UPPER GREAT LAKES. NOT SURE IF GREATER MLCAPES WELL TO SW
OF HERE WILL KEEP MAIN SHRA/TSRA THERE SINCE THE SHORTWAVE IS MUCH
FARTHER NORTH. CARRIED CHANCE POPS OVER WEST CWA...SLIGHT CHANCES
FARTHER EAST. GIVEN THE SHEAR AND INSTABILITY...THERE IS AT LEAST A
REMOTE CHANCE OF STRONG TO SEVERE STORMS AS SHOWN BY LATEST DAY3
OUTLOOK FM SPC.
STRONG SHORTWAVE SLIDES FM ROCKIES TO THE NORTHERN PLAINS SUNDAY
INTO SUNDAY NIGHT. ASSOCIATED SFC LOW BOTTOMS OUT AT 990-1000MB OVER
SOUTHERN MANITOBA BY MONDAY MORNING. MOISTURE ADVECTION AND
CONTINUAL FEED OF STRONG INSTABILITY SHOULD SUPPORT MULTIPLE CLUSTERS
OF SHRA/TSRA WITHIN H85 JET AXIS AND JUST AHEAD OF SFC FRONT. NEVER
SURE HOW FAR SHRA/TSRA WILL BREAK OUT AHEAD OF MAIN FRONT AS WITHOUT
STRONG FORCING FM A YET TO BE DETERMINED SHORTWAVE THERE CAN ALWAYS
BE CAPPING CONCERNS. WILL CONTINUE TO HIGHLIGHT WEST CWA FOR BETTER
CHANCES AT THIS POINT WITH WSW MEAN LAYER WINDS. ANOTHER WARM AND
HUMID DAY AHEAD OF THE FRONT. H85 RIDGE AHEAD OF THE FRONT POINTS TO
READINGS SIMILAR TO SAT AS LONG AS CLOUDS/SHRA/TSRA DONT DISRUPT
THINGS TOO MUCH. PUT THE WARMEST TEMPS ON SUNDAY OVER CNTRL CWA
CLOSER TO LK SUPERIOR WITH DOWNSLOPING SOUTH WINDS. BEST CHANCE FOR
READINGS TO HIT 90 DEGREES WOULD BE BARAGA/BIG
BAY/MARQUETTE/HARVEY/MUNISING.
ALL THIS SHRA/TSRA ACTIVITY SHOULD EASE EAST ACROSS REST OF CWA AS
THE MAIN SFC-H85 FRONTS AND ASSOCIATED THETA-E RIDGE AND RIBBON OF
PWATS OVER 1.75 INCHES CROSS SUNDAY NIGHT INTO MONDAY. MLCAPES OVER
1000J/KG INITIALLY BUT THESE TAIL OFF WITH NIGHTTIME COOLING.
MUCAPES WELL OVER 1000J/KG MAY ALLOW STORMS TO TRY TO BECOME
ELEVATED AFTER BECOMING SFC BASED...BUT THAT IS ALWAYS A TRICKY
TRANSITION. STRONG H85 JET AND MOISTURE TRANSPORT INTO THE AREA
OF HIGHER MUCAPES WILL AID THIS TRANSITION THOUGH. CONSENSUS HIGH
CHANCE TO LOW-END LIKELY POPS SEEMED FINE FOR SUNDAY NIGHT. BETTER
POPS ON LABOR DAY END UP BEING OVER EAST HALF WITH GREATER MOISTURE
ADVECTION AHEAD OF THE EXITING SFC-H85 FRONT. H85 TEMPS DO NOT CRASH
DOWN AS IT LOOKED LIKE A FEW DAYS AGO...SO UPR 70S TO LOW OR
POSSIBLY MID 80S WILL WORK FOR TEMPS ON MONDAY. WARMEST READINGS
CNTRL CWA IRON MTN TO MARQUETTE AND MUNISING. THROUGH THE COOLING IS
NOT AS SIGNIFICANT...THE DRYING IS WITH DWPNTS FALLING OFF INTO THE
50S ON MONDAY AFTN OVER THE WEST AND DOWN TO AROUND 50 BY LATE
MONDAY NIGHT. COULD EVEN SEE 40S DWPNTS ON TUESDAY AS COOLING
BECOMES MORE PRONOUNCED. EXPECT HIGHS UPR 60S TO LOW 70S ON TUE AND
THEN MAINLY IN THE 60S FOR WED. GUSTY WINDS AS THE COOLING OCCURS
ESPECIALLY NEAR LK SUPERIOR. NEXT CHANCE OF RAIN PRETTY WELL AGREED
UPON BY GFS AND ECMWF FOR TUE NIGHT INTO WED MORNING.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 137 PM EDT THU SEP 3 2015
EXPECT VFR CONDITIONS THROUGH THIS EVENING. CLEAR SKIES AND LIGHT
WINDS WILL LIKELY CAUSE IFR CONDITIONS ONCE AGAIN LATER TONIGHT INTO
FRIDAY MORNING...MAINLY AT KIWD/KSAW WHILE MVFR VSBY IS EXPECTED AT
KCMX.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 412 AM EDT THU SEP 3 2015
DENSE FOG HAS DEVELOPED ACROSS THE WESTERN HALF OF THE
LAKE...ESPECIALLY OVER AREAS THAT SAW RAIN YESTERDAY. AS SUCH...HAVE
ISSUED A DENSE FOG ADVY FOR THE ENTIRE WEST HALF OF THE LAKE THROUGH
EARLY THIS AFTERNOON. OTHERWISE...NORTHEAST WINDS OF 10-15KT WILL
CONTINUE TODAY WITH 1-3 FT WAVES ACROSS THE WEST. THE NEXT CHANCE
FOR WINDS GREATER THAN 20KT WILL BE SUNDAY INTO MONDAY AS THE NEXT
SYSTEM APPROACHES FROM THE WEST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
DENSE FOG ADVISORY UNTIL 2 PM EDT /1 PM CDT/ THIS AFTERNOON FOR
LSZ162-240>243-246-247-263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...MRD
LONG TERM...JLA
AVIATION...JLB
MARINE...MRD
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1239 PM EDT THU SEP 3 2015
.UPDATE...
DUAL SHORTWAVES OVER THE WESTERN AND CENTRAL GREAT LAKES WILL
REMAIN THE SOLE FORCING MECHANISMS THROUGH THE NEXT 18 HOURS. THE
SMALL MCS IMPACTING LOWER MICHIGAN IS TIED TO THE FIRST LOWER
COLUMN PV ANOMALY...THE SECOND IS THE SHORTWAVE CIRCULATION THAT
IS NOW DROPPING INTO THE BACKSIDE OF THE GEOPOTENTIAL HEIGHT
WEAKNESS OVER FAR NORTHERN WISCONSIN. AT THE BIG PICTURE...LOWER
DELTA X SOLUTIONS/GLOBAL MODELS SUGGEST A PHASING OF THE TWO
SHORTWAVES AND A SUBSEQUENT STALLING OF THE COMBINED PV ANOMALY
LATE THIS AFTERNOON AND TONIGHT.
THE MCS THAT HAS BEEN PUSHING ACROSS THE NORTHERN CWA CONTINUES TO
MAKE SOME PROGRESS EASTWARD. A LINEAR EXTRAPOLATION OF REGIONAL Z
MOSAIC CONTINUES TO SUPPORT SOME SLIGHT SOUTHWARD DRIFT WITH TIME
ON THE TRACK OF THE MCS. THIS SOUTHWARD DRIFT SHOULD AT LEAST BE
PARTIALLY SUPPORTIVE BY ADDITIONAL OUTFLOW DEVELOPMENT ALONG THE
SOUTHERN FLANK. THERE HAS BEEN SOME MODEST...CONTINUED DEVELOPMENT
DURING THE PAST FEW HOURS. NWP GUIDANCE WITH A BULLISH HRRR AND
BOTH NAM/ECMWF SUPPORT BRING ADDITIONAL CONVECTIVE DEVELOPMENT FOR
ALL OF SOUTHEASTERN MICHIGAN DURING THE AFTERNOON HOURS. GIVEN THE
LACK OF AN AGGRESSIVE SOUTHERN PROGRESSION TO THE
STRATUS/CIRRUS/CU DECK EXPECTATIONS ARE FOR THE
INSTABILITY/BUOYANCY GRADIENT TO REMAIN DRAPED THROUGH FAR
SOUTHERN SECTIONS OF THE CWA. THE FORECAST IS SKEWED ON THE
AGGRESSIVE SIDE WITH RESPECT TO RAIN AND THUNDERSTORM ACTIVITY
THIS LATER THIS AFTERNOON AND EVENING. THERE DOES REMAIN A SLIVER
OF DOUBT THAT THUNDERSTORMS WILL FILL IN COMPLETELY ACROSS FAR
SOUTHERN LOWER MICHIGAN AND IMPACT DETROIT METRO DIRECTLY. STORM
BEHAVIOR TODAY IS EXPECTED TO REMAIN MORE OF A PULSE TYPE NATURE
WITH PERHAPS SOME EMBEDDED LINE TYPE FEATURES. THEREFORE...A LOW
END DAMAGING WIND GUST THREAT EXISTS THIS AFTERNOON AND WILL
PERHAPS BE A CIRCUMSTANCE OF CONSTRUCTIVE CELL MERGERS OR
PRECIPITATION LOADING EFFECTS.
A CONCERNING POTENTIAL WILL CONTINUE TO BE A HEAVY RAINFALL
THREAT...ESPECIALLY UNDER THE DIRECTION OF ADVERTISED PHASING AND
STALLING OUT OF PV MAX OVERHEAD. PWATS ARE AT APPROXIMATELY 1.8
INCHES. SOME SAMPLED RAINFALL RATES EARLIER OFF OF RADAR BASED
PRECIPITATION PRODUCT SUGGESTS 1.25 INCHES OF RAINFALL IS
POSSIBLE IN ROUGHLY 40 MINUTES. WILL BE MONITORING ACTIVITY THIS
AFTERNOON FOR ANY TRAINING OR STATIONARY BEHAVIOR OF THUNDERSTORMS.
&&
.AVIATION...ISSUED 732 AM EDT THU SEP 3 2015
EXTREMELY MOIST AND UNSTABLE ENVIRONMENT TODAY WILL PROVIDE A
FAVORABLE ENVIRONMENT FOR SHOWER AND THUNDERSTORM DEVELOPMENT
AREAWIDE. WHILE THERE REMAINS SOME UNCERTAINTY AS TO POTENTIAL
COVERAGE...CONFIDENCE IS HIGH ENOUGH TO INCLUDE A SPECIFIC MENTION
TO HIGHLIGHT THE MOST LIKELY PERIOD FOR THUNDERSTORMS. OUTSIDE OF
THUNDERSTORMS...EXPANDING COVERAGE OF DIURNAL VFR CU CENTERED ON THE
AFTERNOON/EVENING PERIOD. THE MOIST LOW LEVEL CONDITIONS AND
PROSPECTS FOR WET GROUND WITH RECENT RAINFALL WILL BRING A GREATER
POTENTIAL FOR FOG DEVELOPMENT TONIGHT. POSSIBILITY EXISTS FOR ONE
OR MORE TERMINALS TO DROP INTO LIFR DURING THE EARLY MORNING
PERIOD...CONFIDENCE TOO LOW YET TO INCLUDE BUT WILL HIGHLIGHT WITH
IFR VSBY RESTRICTIONS.
FOR DTW...GREATEST POTENTIAL FOR THUNDERSTORMS CENTERED WITHIN THE
18Z-00Z WINDOW...ALTHOUGH A LOWER PROBABILITY WILL EXIST RIGHT
THROUGH THURSDAY NIGHT.
//DTW THRESHOLD PROBABILITIES...
* LOW FOR CIG AOB 5KFT THIS AFTERNOON AND EVENING
* MEDIUM FOR THUNDERSTORMS THIS AFTERNOON AND EVENING
&&
.PREV DISCUSSION...ISSUED 333 AM EDT THU SEP 3 2015
SHORT TERM...TODAY AND TONIGHT
ATTENTION OVER THE NEXT 24 TO 36 HOURS CENTERS ON THE INBOUND SLOWLY
MOVING MID LEVEL WAVE CURRENTLY CENTERED ACROSS THE LAKE MICHIGAN
CORRIDOR. LITTLE VARIATION IN THE UNDERLYING LOW LEVEL
THERMODYNAMIC PROFILE HEADING INTO TODAY...WITH SE MICHIGAN FIRMLY
ENTRENCHED WITHIN A MOISTURE RICH LOW LEVEL ENVIRONMENT /LOWER 70S
DEWPOINTS/. AS NOTED YESTERDAY...THIS WILL AGAIN TRANSLATE INTO
SUBSTANTIAL LOW LEVEL INSTABILITY (2500+ J/KG SBCAPE) WITHIN A VERY
STEEP LAPSE RATE ENVIRONMENT. INCREASING DPVA AND AN ACCOMPANYING POCKET
OF COOLER MID LEVEL TEMPERATURES WILL CONTRIBUTE AN ADDITIONAL
COMPONENT OF DESTABILIZATION AND MORE FOCUSED ASCENT FOR TODAY.
THIS ENVIRONMENT SEEMS CONDUCIVE FOR A MORE SIZABLE EXPANSION IN
CONVECTIVE COVERAGE LOCALLY...AND WORTHY OF A NUDGE UPWARD IN
POPS...PARTICULARLY FOR THE AFTERNOON/EVENING PERIODS. THE HIGH
MOISTURE CONTENT AND CORRESPONDING POTENTIAL FOR SIGNIFICANT
PRECIPITATION LOADING WITHIN THE DEEPEST CONVECTIVE CELLS WILL
AGAIN PRESENT THE POTENTIAL FOR STRONGER WIND GUSTS...WITH AT
LEAST AN OUTSIDE POSSIBILITY THAT AN ISOLATED STORM OR TWO CAN
GENERATE A PEAK GUST NEARING SEVERE LIMITS. SOLID HEAVY RAINFALL
THREAT GIVEN LIKELY LIMITED STORM MOTION WITHIN THIS HIGH CAPE
ENVIRONMENT. HIGHS TODAY A TOUCH LOWER WITH THE ENSUING EXPANSION
IN CONVECTION/CLOUD COVER LIKELY UNDERCUTTING THE HEATING
POTENTIAL SLIGHTLY. READINGS TOPPING OUT IN THE LOWER AND MIDDLE
80S...HEAT INDICES APPROACHING 90.
GRADUAL COOLING VIA DIABATIC PROCESSES AND ANY OUTFLOW WILL FAVOR A
DIMINISHING TREND TO EXISTING CONVECTIVE ACTIVITY BY EARLY TONIGHT.
HOWEVER THE UNDERLYING ENVIRONMENT WILL STILL REMAIN FAVORABLE FOR
ADDITIONAL ISOLATED-SCATTERED DEVELOPMENT THROUGHOUT THE NIGHT.
INCREASING POTENTIAL FOR FOG OVERNIGHT...MOIST NEAR SURFACE
ENVIRONMENT AUGMENTED BY THE RAINFALL AND WEAK GRADIENT. A CORRIDOR
OF DENSE FOG FOR THE EARLY MORNING COMMUTE NOT OUT OF THE QUESTION.
LONG TERM...
MULTIPLE UPPER WAVES UPSTREAM OVER UPPER MISSISSIPPI RIVER VALLEY
THIS MORNING...WHICH WILL CONSOLIDATE OVER THE WESTERN/CENTRAL GREAT
LAKES TONIGHT INTO FRIDAY...BUT THE EXACT POSITION OF THE DEVELOPED
MID LEVEL CIRCULATION/500 MB LOW IS QUESTION...AS 00Z NAM/GFS ARE
INDICATING A FARTHER SOUTH/WEST SOLUTION...NEAR CHICAGO...WHILE
EURO/CANADIAN REMAIN STEADFAST WITH 500 MB LOW FARTHER NORTH/EAST
OVER NORTHERN LOWER MICHIGAN. EITHER WAY...CHANCE POPS STILL SEEM
WARRANTED...EVEN WITH THE STRENGTHENING HIGH PRESSURE OVER EASTERN
CANADA (1025 MB)...AS THE LOW LEVEL SOUTHEAST/EAST FLOW WILL
INCREASE A BIT...BUT THERE ACTUALLY LOOKS TO BE MODEST MOISTURE
ADVECTION FROM WESTERN PA/LAKE ERIE. MLCAPES PROGGED TO INCREASE
INTO THE 500 TO 1500 J/KG RANGE DURING FRIDAY...PER 00Z EURO.
STILL LINGERING UPPER LEVEL TROUGHINESS ON SATURDAY WITH MLCAPES
RISING INTO THE 1000-2000 J/KG RANGE TO SUPPORT LOW CHANCE POPS.
UPPER LEVEL RIDGE BUILDING OUT AHEAD OF STRONG GREAT BASIN 500 MB
LOW ON SATURDAY SHOULD EXERT A BIGGER INFLUENCE FOR THE SECOND HALF
OF THE WEEKEND...ALLOWING FOR TEMPERATURES TO HEAT UP ONCE
AGAIN...WITH 90 DEGREES LIKELY ON SUNDAY...AS SOUTH-SOUTHWEST FLOW
INCREASES OUT AHEAD OF NEXT COLD FRONT...WITH 850 MB TEMPS PROGGED
TO BE IN THE 18-19 C RANGE. UPPER LEVEL RIDGE AXIS ARRIVING SUNDAY
AFTERNOON IS EXPECTED TO PROVIDE ENOUGH MID LEVEL WARMING/SUBSIDENT
BACKDROP TO SQUELCH POTENTIAL CONVECTION. THE SAME CAN NOT BE SAID
FOR EARLY NEXT WEAK AS SOLID HEIGHT FALLS/MOISTURE PLUME/AXIS (PW
VALUES OF 2 INCHES) AND COLD FRONT TRACKS THROUGH THE GREAT LAKES
REGION.
MARINE...
STRENGTHENING HIGH PRESSURE OVER EASTERN CANADA WILL PROMOTE LIGHT
EASTERLY FLOW AS WE HEAD INTO FRIDAY. UPPER LEVEL DISTURBANCE WILL
RESULT IN SCATTERED SHOWERS AND THUNDERSTORMS THROUGH FRIDAY...WITH
A LOW CHANCE ON SATURDAY. WINDS WILL SHIFT TO THE SOUTH OVER THE
WEEKEND...BUT REMAIN LIGHT...AS VERY WARM AIR STREAMS INTO THE
REGION.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
UPDATE.......CB
AVIATION.....MR
SHORT TERM...MR
LONG TERM....SF
MARINE.......SF
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MEDFORD OR
1145 AM PDT THU SEP 3 2015
.DISCUSSION...THE LATEST VISIBLE IMAGE SHOWS A BAND OF CLOUDS
MOVING SOUTHWEST TO NORTHEAST IN SOUTHEAST KLAMATH, LAKE EASTERN
SISKIYOU AND MOST OF MODOC COUNTY. A FEW RAWS SITES IN THESE
LOCATIONS PICKED UP LIGHT RAINFALL WITH ANYWHERE BETWEEN 0.01 AND
0.10 OF AN INCH BETWEEN LAST NIGHT AND THIS MORNING. THE RADAR
IMAGE IS NOT SHOWING ANYTHING BECAUSE THE RAIN IS OCCURRING AT
LOWER LEVELS WHICH IS NOT BEING PICKED UP. MEANWHILE A ISOLATED
SHOWERS IN ASSOCIATION WITH A WEAK SHORTWAVE TROUGH WITHIN THE
MUCH LARGER UPPER LOW IS MOVING INLAND JUST NORTH OF OUR FORECAST
AREA. THESE ISOLATED SHOWERS SHOULD REMAIN TO OUR NORTH TODAY.
THE UPPER LOW WILL MOVE SOUTH TONIGHT AND MORE SHORTWAVE ENERGY
WILL ROTATE AROUND THE UPPER LOW WITH THE FIRST IN A SERIES
EXPECTED TO SWING INTO NORTHWEST CAL EARLY FRIDAY MORNING. COLD
AIR ALOFT WITH 500MB TEMPERATURES NEAR -23C WILL OVER THE MARINE
WATERS LATE TONIGHT SO COULD NOT RULE OUT AN ISOLATED THUNDERSTORM
OR TWO.
FRIDAY WILL BE THE MOST ACTIVE DAY IN THE PERIOD AS THE UPPER LOW
AND COLD AIR ALOFT MOVES OVERHEAD WITH SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS. IT`S POSSIBLE WE COULD HAVE MORE
THUNDERSTORM ACTIVITY FRIDAY AFTERNOON EAST OF THE CASCADES. IT`S
ALSO POSSIBLE SOME THUNDERSTORMS COULD PRODUCE GUSTY WINDS AND
SMALL HAIL. -PETRUCELLI
&&
.AVIATION...FOR THE 03/18Z TAF CYCLE... VFR CONDITIONS ARE EXPECTED
TO PREVAIL THROUGH TODAY AT VALLEY LOCATIONS. PARTIAL MOUNTAIN
OBSCURATION SHOULD BE EXPECTED ACROSS MOST MOUNTAIN AREAS TODAY,
PRIMARILY EAST OF MOUNT SHASTA AND KLAMATH FALLS AND FROM THE UMPQUA
DIVIDE NORTHWARD. LATE TONIGHT THROUGH FRIDAY MORNING SCATTERED MVFR
CEILINGS ARE POSSIBLE ON THE COAST NORTH OF CAPE BLANCO AND FROM THE
UMPQUA DIVIDE NORTHWARD. CLOUDS WILL INCREASE AFTER SUNRISE FRIDAY
MORNING, ESPECIALLY EAST OF THE COAST RANGE, WITH DETERIORATING
CIG/VIS CONDITIONS IN SHOWERS AND ISOLATED THUNDERSTORMS FRIDAY
AFTERNOON. BTL
&&
.MARINE...UPDATED 830 AM PDT THURSDAY 3 SEPTEMBER 2015...SMALL CRAFT
ADVISORY LEVEL NORTH WINDS AT THE LOW END OF CRITERIA WILL DEVELOP
SOUTH OF GOLD BEACH BEYOND 5 NM FROM SHORE LATE THIS MORNING. THESE
WINDS WILL REACH A PEAK IN THE EARLY EVENING THEN DIMINISH OVERNIGHT
BEFORE RETURNING TO ABOUT THE SAME STRENGTH FOR LATE FRIDAY MORNING
THROUGH FRIDAY EVENING. AFTER ANOTHER DECREASE IN WINDS LATE FRIDAY
NIGHT, WINDS WILL BECOME STRONGER DURING THE WEEKEND. WINDS WILL
STILL BE MODERATE SATURDAY BUT GALES ARE POSSIBLE IN THE SOUTHERN
OUTER WATERS WITH SMALL CRAFT WINDS ELSEWHERE SUNDAY INTO MONDAY.
WINDS ARE EXPECTED TO RETURN TO MODERATE STRENGTH BEYOND MONDAY.
BTL/DW
&&
.PREV DISCUSSION... /ISSUED 351 AM PDT THU SEP 3 2015/
DISCUSSION...A COLD FRONT THAT MOVED THROUGH LATE WEDNESDAY HAS
LEFT MOST OF THE AREA 5 TO 10 DEGREES COOLER VERSUS THIS TIME VERSUS
YESTERDAY. EVENING SHIFT PUT UP A FROST ADVISORY FOR SOME OF THE
EAST SIDE. THE DAY SHIFT TODAY WILL NEED TO CONSIDER THE SAME FOR
TONIGHT AND FRIDAY NIGHT AS THE CENTER OF AN UNUSUALLY COLD UPPER
LOW DIVES IN OVERHEAD. THIS LOW WILL BRING THE COOLEST AIR OF THE
SEASON WITH A COLD CORE OF -25C AT 500 MILLIBARS. AS THE TROUGH
SWINGS EASTWARD AND SKIES CLEAR SATURDAY NIGHT INTO SUNDAY...
THERE WILL BE A THREAT FOR FREEZING MORNING TEMPERATURES ACROSS
MUCH OF THE LOWLANDS EAST OF THE CASCADES. A SPECIAL WEATHER
STATEMENT WILL COVER THIS UPCOMING POTENTIAL FOR FROST AND FREEZE
FOR AGRICULTURAL INTERESTS.
RAIN WITH THIS SYSTEM TODAY SHOULD REMAIN FAIRLY SLIM. THE 88D IS
CURRENTLY SHOWING SOME WEAK ECHOES STREAMING SOUTHWEST TO
NORTHEAST BETWEEN KLAMATH FALLS AND LAKEVIEW IN REGION OF COLDER
CLOUD TOPS BETWEEN -10 TO -15C IN THICKER CLOUD. PER THE RUC AND
HRRR FORECASTS, WE DID BUMP UP PROBABILITIES A BIT FOR A HUNDREDTH
OR TWO OUR THERE AROUND SOUTHERN LAKE COUNTY WITH SHORT WAVE
ENERGY OVERRIDING THE SLOWLY PROGRESSING FRONTAL ZONE. THIS SHOULD
TAPER OFF THIS EVENING WITH A FAIRLY UNEVENTFUL NIGHT IN STORE.
ACTIVITY WILL INCREASE FRIDAY WITH THE APPROACH OF THE DEEP UPPER
LOW FROM THE NORTH. FAIRLY STRONG SHORT WAVE ENERGY IS FORECAST TO
DIG THROUGH THE BASE OF THE TROUGH OVER SOUTHERN OREGON AND NORTHERN
CALIFORNIA FRIDAY AFTERNOON AND EVENING. WITH THE COLD AIR ALOFT,
NUMEROUS SHOWERS AND A SLIGHT CHANCE FOR THUNDERSTORMS WITH SOME
LOCALIZED MODERATE RAINS ARE IN STORE. THE BEST SHOT AT GOOD RAIN
WILL BE EAST OF THE CASCADES. DUE TO BUILDING CONFIDENCE BASED ON
SUPPORT FROM RECENT MODEL RUNS, HAVE ALSO BUMPED UP POPS A BIT
MORE IN THIS TIME FRAME.
SHOWERS WILL BE LINGERING INTO SATURDAY MORNING MAINLY FROM THE
CASCADES EAST. SNOW LEVELS EARLY SATURDAY SHOULD BOTTOM OUT BETWEEN
6000 AND 6500 FEET OVER THE CASCADES, AND MORE LIKE 7KFT IN
NORTHERN CALIFORNIA. SO, A LITTLE DUSTING ON THE HIGHER TERRAIN
LOOKS LIKELY. SOME UNCERTAINTY EXISTS FOR AREAS IN LAKE COUNTY
WHERE THE MORE SIGNIFICANT PRECIP WILL FALL. THE WARNERS INCLUDING
HART MTN AREA ABOVE 6500 FEET SHOULD BE AWARE OF THE POTENTIAL FOR
A LITTLE MORE SNOW THERE.
AS THE SYSTEM CLEARS OUT SATURDAY AFTERNOON AND NIGHT, THIS WILL
LEAVE SUNDAY MORNING WITH A FAIR POTENTIAL TO FREEZE IN MANY AREAS
OF WHAT LOOKS LIKE MAINLY LAKE AND MODOC COUNTIES. A WARMING TREND
LOOKS LIKELY THEREAFTER THROUGH LATE WEEK. STAVISH
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR
PZZ356-376.
SMALL CRAFT ADVISORY FROM 11 AM TO 11 PM PDT FRIDAY FOR PZZ376.
$$
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1229 PM CDT THU SEP 3 2015
.AVIATION...
VFR LEVEL CIGS WILL HANG ON FOR A FEW MORE HOURS IN AUSTIN AND SAN
ANTONIO. WINDS WILL PICK UP TO AROUND 10 KTS FROM THE SOUTHEAST AT
ALL TERMINALS THIS AFTERNOON. DEEP LAYER SOUTHEASTERLY FLOW WILL
CONTINUE THROUGH THE PERIOD AND MVFR CIGS WILL DEVELOP AGAIN
OVERNIGHT AT ALL TERMINALS. IMPROVEMENT TO VFR WILL COME LATE
MORNING FRIDAY.
&&
.PREV DISCUSSION... /ISSUED 1002 AM CDT THU SEP 3 2015/
UPDATE...NO SIGNIFICANT UPDATES THIS MORNING WITH TODAYS FORECAST
ON TRACK WEATHER AND TEMPERATURE WISE. ONE SMALL ADJUSTMENT MADE
WAS SLIGHTLY REDUCING THE 30% POP IN LAVACA AND FAYETTE COUNTIES
TO 20% AND SHIFTING THE 30% AREA INTO KARNES COUNTY THROUGH 1PM.
THIS SHIFTING WAS DUE TO ONGOING RADAR TRENDS. HOURLY DEWPOINTS
WERE ALSO INCREASED ACROSS EASTERN LOCATIONS TO BETTER MATCH
OBSERVATIONS. UPDATES ARE OUT AND MORE DETAILS CAN BE FOUND BELOW
IN THE UPDATED DISCUSSION.
DISCUSSION... SOME SHOWERS ARE ONGOING ALONG THE COAST AND EXTEND
INLAND INTO DEWITT AND KARNES COUNTY THIS MORNING. ADDITIONAL
ISOLATED TO SCATTERED SHOWERS WILL BE LIKELY THROUGH THE AFTERNOON
PRIMARILY EAST OF THE I-35/37 CORRIDOR WHERE THE SEA-BREEZE
ACTIVITY WILL BE MORE PRONOUNCED. WATER VAPOR AND MID TO UPPER
LEVEL RAP ANALYSIS DEPICTS A CLOSED CUT-OFF LOW OVER THE GULF OF
MEXICO SE OF THE TEXAS COAST. THIS FEATURE MAY BE JUST DISTANT
ENOUGH NOT TO HAVE TO MUCH BEARING ON OUR WEATHER TODAY OTHER THAN
DEEPER LEVEL STEERING FLOW FROM THE EAST. THIS FLOW MAY HELP SOME
SEA-BREEZE ACTIVITY PUSH FROM THE EAST TO WEST TOWARDS THE 35
CORRIDOR THIS AFTERNOON AND EARLY EVENING. HOWEVER...OVERALL
CHANCES REMAIN LOW WITH 20-30%. LOW 800-500MB LAPSE RATES AND A
WARM NOSE NEAR 500MB WILL HAMPER DEEPER DEVELOPMENT OF THE
CONVECTION AND THUNDERSTORMS MAY BE HARD TO COME BY IN THIS
ENVIRONMENT. AN UPDATE DURING THE AFTN MAY REMOVE THE CURRENT
THUNDER WORDING AND BE REPLACED WITH GENERAL SHOWERS INSTEAD.
PREV DISCUSSION... /ISSUED 650 AM CDT THU SEP 3 2015/
AVIATION...
STRATUS CLOUDS CONTINUE TO DEVELOP THIS MORNING...WITH MVFR CIGS
ALREADY IN PLACE ACROSS MOST AREAS. STILL THINK THERE IS SOME
OPPORTUNITY FOR IFR CIGS FOR THE NEXT FEW HOURS AND WILL MENTION
TEMPO GROUPS ALONG THE I-35 CORRIDOR THROUGH 15Z. IMPROVING
CONDITIONS ARE IN STORE AFTER 16Z-17Z WITH VFR CONDITIONS
RETURNING TO ALL TERMINALS. ISOLATED CONVECTION IS STILL POSSIBLE
TODAY...BUT GIVEN LACK OF COVERAGE...WILL NOT MENTION IN THE
FORECAST AT THIS TIME. LOW CLOUDS WILL DEVELOP AFTER LATE TONIGHT
INTO FRIDAY MORNING...WITH MVFR CIGS EXPECTED AFTER 04/08Z. WINDS
WILL GENERALLY REMAIN FROM THE EAST AND SOUTHEAST AT OR BELOW
10KTS THROUGH THE PERIOD.
PREV DISCUSSION... /ISSUED 419 AM CDT THU SEP 3 2015/
SHORT TERM (TODAY THROUGH FRIDAY)...
WV IMAGERY AND UPPER AIR ANALYSES SHOW THAT THE WEAK SHEAR AXIS
AND ASSOCIATED TROUGH THAT STRETCHES FROM THE LOWER MISSISSIPPI
RIVER VALLEY TO THE SE TX AND LA GULF COAST CONTINUES TO WEAKEN.
ISOLATED SHOWERS AND THUNDERSTORMS ARE FORMING OVER THE GULF AND
MOVING ONSHORE...BUT THE COVERAGE IS LOWER THAN THE LAST FEW
NIGHTS. MOST OF THESE SHOWERS WILL DISSIPATE...BUT A ROGUE
SHOWER OR TWO MAY MOVE INTO OUR SE COUNTIES TOWARDS DAYBREAK. LOW
STRATUS HAS BEEN SLOWER TO DEVELOP TONIGHT THAN THE PREVIOUS FEW
EVENINGS...BUT STILL EXPECT THEM TO MOVE IN WITHIN THE NEXT FEW
HOURS AND PERSIST FOR A FEW HOURS AFTER SUNRISE TODAY AND FRIDAY.
MODELS ARE CONSISTENT IN BUILDING AND INTENSIFYING THE UPPER
LEVEL RIDGE OVER THE SOUTHERN PLAINS TODAY AND FRIDAY AS AN
INVERTED TROUGH BREAKS OFF FROM THE PROGRESSIVE TROUGH AND
RETROGRADES UNDER THE RIDGE AS IT WEAKENS. THIS WILL HELP CAUSE A
0.2-0.3 INCH SURGE IN PWAT VALUES AND SLIGHTLY DEEPER CONVERGENCE
WITH THE SEA BREEZE THAN OCCURRED ON WEDNESDAY...ALLOWING FOR
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS IN THE COASTAL
PLAINS THAT WILL DISSIPATE AS THEY MOVE INTO THE I-35 CORRIDOR.
MODELS HAVE GENERALLY BACKED OFF FROM SHOWERS MOVING INTO THE HILL
COUNTRY EXCEPT FOR THE ECMWF AND A FEW HI-RES MODELS FOR FRIDAY.
LONG TERM (FRIDAY NIGHT THROUGH WEDNESDAY)...
THE UPPER LEVEL RIDGE WILL CONTINUE TO INTENSIFY THROUGH THE
WEEKEND AS THE RETROGRADING SHEAR AXIS DISSIPATES. THIS WILL LEAD
TO HOT AND GENERALLY DRY DAYS ASIDE FROM ISOLATED AFTERNOON
SHOWERS AND THUNDERSTORMS IN THE COASTAL PLAINS ON SATURDAY. HEAT
INDEX VALUES WILL RISE INTO THE 100-105 RANGE EVERYWHERE EXCEPT
THE COUNTRY FOR ALL OF LABOR DAY WEEKEND...WITH HIGH TEMPS IN THE
MID-TO-UPPER 90S EXCEPT FOR A FEW SPOTS IN THE RIO GRANDE PLAINS
THAT REACH THE CENTURY MARK. THE RIDGE GRADUALLY BEGINS TO WEAKEN
AND SLIDE TO THE WEST BY WEDNESDAY...WHICH MAY ALLOW A WEAK FRONT
TO MOVE INTO THE REGION LATE THURSDAY INTO FRIDAY JUST PAST THE
FORECAST PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 73 95 75 97 76 / 20 20 10 10 -
AUSTIN BERGSTROM INTL AIRPORT 72 94 73 96 73 / 20 20 10 10 -
NEW BRAUNFELS MUNI AIRPORT 73 96 74 97 75 / 20 20 10 10 -
BURNET MUNI AIRPORT 73 94 73 95 74 / 10 10 10 10 -
DEL RIO INTL AIRPORT 75 97 76 98 77 / 10 10 10 10 -
GEORGETOWN MUNI AIRPORT 73 94 75 95 75 / 10 10 10 10 -
HONDO MUNI AIRPORT 73 96 74 97 73 / 10 10 10 10 -
SAN MARCOS MUNI AIRPORT 73 94 75 96 74 / 20 20 10 10 -
LA GRANGE - FAYETTE REGIONAL 73 94 75 95 76 / 30 20 10 20 10
SAN ANTONIO INTL AIRPORT 74 95 76 96 76 / 20 10 10 10 -
STINSON MUNI AIRPORT 74 96 76 97 75 / 20 10 10 10 -
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...05
SYNOPTIC/GRIDS...ALLEN
PUBLIC SERVICE/DATA COLLECTION...30
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1143 AM MDT THU SEP 3 2015
.UPDATE...
ISSUED AT 1006 AM MDT THU SEP 3 2015
SHOWERS ARE SPREADING NORTHWARD OUT OF NORTHEAST COLORADO AT THIS
TIME. SHOWER ACTIVITY WILL SLOWLY CONTINUE NORTHWARD THROUGH THIS
AFTERNOON AND EVENING IN ASSOCIATION WITH A WEAK SHORTWAVE MOVING
THROUGH SOUTHWEST FLOW ALOFT. A FEW EMBEDDED THUNDERSTORMS WILL
ALSO DEVELOP THIS AFTERNOON BUT THERE IS NO THREAT FOR SEVERE
THUNDERSTORMS.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 300 AM MDT THU SEP 3 2015
PRETTY QUIET WEATHER EARLY THIS MORNING ACROSS THE FORECAST AREA.
CURRENT WATER VAPOR LOOP SHOWS A RIDGE AXIS BUILDING OVER THE
GREAT PLAINS AS A BROAD UPPER LEVEL TROUGH SETTLES OVER THE
PACIFIC NORTHWEST...BRINGING MUCH NEEDED RAINFALL TO WASHINGTON
AND OREGON. THIS SYSTEM WILL EVENTUALLY IMPACT WYOMING THIS
WEEKEND. BEFORE THIS...CURRENT WATER VAPOR ALSO SHOWS A WELL
DEFINED SHORTWAVE DISTURBANCE ALOFT NEAR THE FOUR CORNERS REGION
WITH MID TO HIGH CLOUDS MOVING NORTHWARD WELL AHEAD OF IT. THIS
FEATURE WILL BE THE MAIN FORECAST CONCERN TODAY. A FEW MODELS
SHOW THIS FEATURE MOVING OVER SOUTHEAST WYOMING THIS AFTERNOON
PRODUCING SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS.
THUNDERSTORMS MAY PRODUCE SOME HEAVY RAINFALL AS SHORT RANGE
MODELS SUCH AS THE HRRR INDICATE REDEVELOPMENT AND TRAINING OVER
THE SAME AREA INTO LATE THIS EVENING. THIS IS DUE TO A POTENT
UPPER LEVEL JET AND GOOD 300MB DIFFLUENCE ALOFT. HOWEVER...NOT
ALL MODELS AGREE ON THE TIMING OF THIS FEATURE...WITH THE ECMWF
AND GEM 3 TO 6 HOURS BEHIND THE GFS. DUE TO PEAK HEATING AND
AVAILABLE INSTABILITY...THIS TIMING DIFFERENCE IS SIGNIFICANT. THE
NEW 06Z NAM IS IN GOOD AGREEMENT WITH THE GFS AND HRRR...SO
CONFIDENCE IS INCREASING THAT SEVERAL BANDS OF SHOWERS AND TSTORMS
WILL DEVELOP OVER THE ROCKY MOUNTAINS AND QUICKLY LIFT NORTHEAST
ACROSS THE I25 AND I80 CORRIDORS BY THIS AFTERNOON. INCREASED POP
ACROSS MOST OF THE AREA WITH THE EXCEPTION OF CARBON COUNTY.
INCREASED POP BETWEEN 30 TO 60 PERCENT FURTHER SOUTH AND
WEST...SINCE THERE IS STILL LOW CONFIDENCE IN SHOWER/TSTORM
COVERAGE NORTH OF THE PLATTE RIVER VALLEY DUE TO TIMING
DIFFERENCES.
FRIDAY WILL BE PRETTY SIMILAR TO THURSDAY WITH HIGH TEMPERATURES
IN THE 80S TO MID 90S AND ANOTHER GOOD CHANCE OF AFTERNOON SHOWERS
AND TSTORMS. IN FACT...CONDITIONS APPEAR MORE FAVORABLE IN THE
EVENING AS THE NAM...GFS...AND ECMWF SHOW QUITE A BIT OF UPPER
LEVEL DIFFLUENCE DUE TO JET DYNAMICS ALOFT. THIS DYNAMIC LIFT
PEAKS BETWEEN 00Z TO 06Z FRIDAY EVENING BEFORE LIFTING NORTHEAST.
INCREASED POP UP TO 45 PERCENT ACROSS THE HIGH PLAINS FRIDAY
EVENING.
THE UPPER LEVEL TROUGH OVER THE PACIFIC NORTHWEST WILL MOVE
TOWARDS THE FORECAST AREA ON SATURDAY. IT WILL BE SLIGHTLY COOLER
WITH HIGHS IN THE UPPER 70S TO UPPER 80S...BUT THE PRIMARY COLD
FRONT WILL NOT ENTER SOUTHEAST WYOMING UNTIL LATE SATURDAY NIGHT.
THIS MAIN STORM SYSTEM IS EXPECTED TO MOVE NORTHEAST AND REMAIN
NORTH OF THE FORECAST AREA. KEPT POP BETWEEN 10 TO 20 PERCENT WITH
THE HIGHEST CHANCE ACROSS THE MOUNTAINS...DUE TO SOME DRIER AIR
ALOFT AND A STABLE LAYER AROUND 500MB WHICH WILL INHIBIT WIDESPREAD
CONVECTION.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 230 AM MDT THU SEP 3 2015
THE UPPER LEVEL TROUGH WILL SWING NORTHEASTWARD ACROSS NORTHERN WY
ON SAT NIGHT AND SUN MORNING WITH AN ASSOCIATED FROPA. WINDS WILL
REALLY INCREASE BEHIND THE FRONT ON SUN MORNING AS THE MODELS SHOW
700MB WINDS OF 35-40 KTS OVER SOUTHEAST WY. THE GRADIENT DOES BEGIN
TO RELAX BY THE AFTN SO WINDS WILL COME DOWN SOME. WITH A VERY DRY
AIR MASS IN PLACE ON SUN AND MIN RH VALUES FALLING TO AROUND 15
PERCENT...THERE WILL LIKELY BE SOME FIRE WEATHER CONCERNS DESPITE
THE COOLER TEMPS. DRY WESTERLY MID LEVEL FLOW WILL REMAIN IN PLACE
THROUGH EARLY NEXT WEEK WITH PW VALUES OF ONLY 0.25-0.5 INCHES AND
NO HINT OF ANY MONSOONAL MOISTURE INTRUSION. TEMPS WILL BE AROUND
NORMAL FOR EARLY SEP WITH COOLER NIGHTS THAN WE HAVE SEEN RECENTLY.
THE MODEL DIFFERENCES BETWEEN THE GFS AND ECMWF REALLY BEGIN TO SHOW
UP BY TUESDAY AS THE GFS SHOWS A STRONGER SHORTWAVE MOVING ACROSS WY.
REGARDLESS OF THE SOLUTION...A DRY FCST WILL PREVAIL WITH LIMITED
MOISTURE AND DYNAMICS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1138 AM MDT THU SEP 3 2015
VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD. WEST TO
SOUTHWEST SURFACE WINDS WILL BE BREEZY AT TIMES ACROSS SOUTHEAST
WY WITH GUSTS TO 25 KT POSSIBLE THIS AFTERNOON. SCATTERED SHOWERS
AND ISOLATED TSTORMS OVER NE CO WILL SPREAD NORTHEAST INTO
SOUTHEAST WY AND WESTERN NE THROUGH THE EVENING. GUSTY WINDS AND
BRIEF MVFR VISIBILITY IN MODERATE TO HEAVY RAIN WILL BE POSSIBLE.
&&
.FIRE WEATHER...
ISSUED AT 230 AM MDT THU SEP 3 2015
IT WILL BE PRETTY DRY INITIALLY THIS AFTERNOON OVER EAST CENTRAL
WYOMING BEFORE SOME SUBTROPICAL MOISTURE MOVES INTO THE
AREA...AHEAD OF AN UPPER LEVEL DISTURBANCE. ALTHOUGH FIRE WEATHER
CONCERNS ARE LOW TODAY...WILL HAVE TO MONITOR WIND SPEEDS ACROSS
ZONE 301 AND 302. FOR NOW...WINDS ARE EXPECTED TO BE BELOW 20 MPH
AT THIS TIME. MINIMAL FIRE WEATHER CONCERNS ARE ANTICIPATED FRIDAY
AND SATURDAY AS THUNDERSTORM COVERAGE WILL INCREASE AND RELATIVE
HUMIDITIES WILL TREND HIGHER...MINIMUM DAYTIME RELATIVE HUMIDITIES
WILL BE BETWEEN 20 TO 30 PERCENT BY SATURDAY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...SML
SHORT TERM...TJT
LONG TERM...ZF
AVIATION...MAJ
FIRE WEATHER...TJT
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1017 AM MDT THU SEP 3 2015
.UPDATE...
ISSUED AT 1006 AM MDT THU SEP 3 2015
SHOWERS ARE SPREADING NORTHWARD OUT OF NORTHEAST COLORADO AT THIS
TIME. SHOWER ACTIVITY WILL SLOWLY CONTINUE NORTHWARD THROUGH THIS
AFTERNOON AND EVENING IN ASSOCIATION WITH A WEAK SHORTWAVE MOVING
THROUGH SOUTHWEST FLOW ALOFT. A FEW EMBEDDED THUNDERSTORMS WILL
ALSO DEVELOP THIS AFTERNOON BUT THERE IS NO THREAT FOR SEVERE
THUNDERSTORMS.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 300 AM MDT THU SEP 3 2015
PRETTY QUIET WEATHER EARLY THIS MORNING ACROSS THE FORECAST AREA.
CURRENT WATER VAPOR LOOP SHOWS A RIDGE AXIS BUILDING OVER THE
GREAT PLAINS AS A BROAD UPPER LEVEL TROUGH SETTLES OVER THE
PACIFIC NORTHWEST...BRINGING MUCH NEEDED RAINFALL TO WASHINGTON
AND OREGON. THIS SYSTEM WILL EVENTUALLY IMPACT WYOMING THIS
WEEKEND. BEFORE THIS...CURRENT WATER VAPOR ALSO SHOWS A WELL
DEFINED SHORTWAVE DISTURBANCE ALOFT NEAR THE FOUR CORNERS REGION
WITH MID TO HIGH CLOUDS MOVING NORTHWARD WELL AHEAD OF IT. THIS
FEATURE WILL BE THE MAIN FORECAST CONCERN TODAY. A FEW MODELS
SHOW THIS FEATURE MOVING OVER SOUTHEAST WYOMING THIS AFTERNOON
PRODUCING SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS.
THUNDERSTORMS MAY PRODUCE SOME HEAVY RAINFALL AS SHORT RANGE
MODELS SUCH AS THE HRRR INDICATE REDEVELOPMENT AND TRAINING OVER
THE SAME AREA INTO LATE THIS EVENING. THIS IS DUE TO A POTENT
UPPER LEVEL JET AND GOOD 300MB DIFLUENCE ALOFT. HOWEVER...NOT ALL
MODELS AGREE ON THE TIMING OF THIS FEATURE...WITH THE ECMWF AND
GEM 3 TO 6 HOURS BEHIND THE GFS. DUE TO PEAK HEATING AND AVAILABLE
INSTABILITY...THIS TIMING DIFFERENCE IS SIGNIFICANT. THE NEW 06Z
NAM IS IN GOOD AGREEMENT WITH THE GFS AND HRRR...SO CONFIDENCE IS
INCREASING THAT SEVERAL BANDS OF SHOWERS AND TSTORMS WILL DEVELOP
OVER THE ROCKY MOUNTAINS AND QUICKLY LIFT NORTHEAST ACROSS THE I25
AND I80 CORRIDORS BY THIS AFTERNOON. INCREASED POP ACROSS MOST OF
THE AREA WITH THE EXCEPTION OF CARBON COUNTY. INCREASED POP
BETWEEN 30 TO 60 PERCENT FURTHER SOUTH AND WEST...SINCE THERE IS
STILL LOW CONFIDENCE IN SHOWER/TSTORM COVERAGE NORTH OF THE PLATTE
RIVER VALLEY DUE TO TIMING DIFFERENCES.
FRIDAY WILL BE PRETTY SIMILAR TO THURSDAY WITH HIGH TEMPERATURES
IN THE 80S TO MID 90S AND ANOTHER GOOD CHANCE OF AFTERNOON SHOWERS
AND TSTORMS. IN FACT...CONDITIONS APPEAR MORE FAVORABLE IN THE
EVENING AS THE NAM...GFS...AND ECMWF SHOW QUITE A BIT OF UPPER
LEVEL DIFLUENCE DUE TO JET DYNAMICS ALOFT. THIS DYNAMIC LIFT PEAKS
BETWEEN 00Z TO 06Z FRIDAY EVENING BEFORE LIFTING NORTHEAST.
INCREASED POP UP TO 45 PERCENT ACROSS THE HIGH PLAINS FRIDAY
EVENING.
THE UPPER LEVEL TROUGH OVER THE PACIFIC NORTHWEST WILL MOVE
TOWARDS THE FORECAST AREA ON SATURDAY. IT WILL BE SLIGHTLY COOLER
WITH HIGHS IN THE UPPER 70S TO UPPER 80S...BUT THE PRIMARY COLD
FRONT WILL NOT ENTER SOUTHEAST WYOMING UNTIL LATE SATURDAY NIGHT.
THIS MAIN STORM SYSTEM IS EXPECTED TO MOVE NORTHEAST AND REMAIN
NORTH OF THE FORECAST AREA. KEPT POP BETWEEN 10 TO 20 PERCENT WITH
THE HIGHEST CHANCE ACROSS THE MOUNTAINS...DUE TO SOME DRIER AIR
ALOFT AND A STABLE LAYER AROUND 500MB WHICH WILL INHIBIT WIDESPREAD
CONVECTION.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 230 AM MDT THU SEP 3 2015
THE UPPER LEVEL TROUGH WILL SWING NORTHEASTWARD ACROSS NORTHERN WY
ON SAT NIGHT AND SUN MORNING WITH AN ASSOCIATED FROPA. WINDS WILL
REALLY INCREASE BEHIND THE FRONT ON SUN MORNING AS THE MODELS SHOW
700MB WINDS OF 35-40 KTS OVER SOUTHEAST WY. THE GRADIENT DOES BEGIN
TO RELAX BY THE AFTN SO WINDS WILL COME DOWN SOME. WITH A VERY DRY
AIR MASS IN PLACE ON SUN AND MIN RH VALUES FALLING TO AROUND 15
PERCENT...THERE WILL LIKELY BE SOME FIRE WEATHER CONCERNS DESPITE
THE COOLER TEMPS. DRY WESTERLY MID LEVEL FLOW WILL REMAIN IN PLACE
THROUGH EARLY NEXT WEEK WITH PW VALUES OF ONLY 0.25-0.5 INCHES AND
NO HINT OF ANY MONSOONAL MOISTURE INTRUSION. TEMPS WILL BE AROUND
NORMAL FOR EARLY SEP WITH COOLER NIGHTS THAN WE HAVE SEEN RECENTLY.
THE MODEL DIFFERENCES BETWEEN THE GFS AND ECMWF REALLY BEGIN TO SHOW
UP BY TUESDAY AS THE GFS SHOWS A STRONGER SHORTWAVE MOVING ACROSS WY.
REGARDLESS OF THE SOLUTION...A DRY FCST WILL PREVAIL WITH LIMITED
MOISTURE AND DYNAMICS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 532 AM MDT THU SEP 3 2015
VFR CONDITIONS THROUGH THE TAF PERIOD. WINDS WILL MOSTLY REMAIN
BELOW 15 KTS...EXCEPT AT RWL WHERE GUSTS TO 20 KTS WILL BE
POSSIBLE DURING THE AFTERNOON. ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS WILL DEVELOP AFTER 20Z ACROSS SOUTHEAST WY AND THEN
MOVE EASTWARD INTO THE NEBRASKA PANHANDLE THROUGH THE EVENING.
GUSTY AND ERRATIC WINDS ALONG WITH BRIEF HEAVY RAIN WILL BE
POSSIBLE WITH THE STORMS.
&&
.FIRE WEATHER...
ISSUED AT 230 AM MDT THU SEP 3 2015
IT WILL BE PRETTY DRY INITIALLY THIS AFTERNOON OVER EAST CENTRAL
WYOMING BEFORE SOME SUBTROPICAL MOISTURE MOVES INTO THE
AREA...AHEAD OF AN UPPER LEVEL DISTURBANCE. ALTHOUGH FIRE WEATHER
CONCERNS ARE LOW TODAY...WILL HAVE TO MONITOR WIND SPEEDS ACROSS
ZONE 301 AND 302. FOR NOW...WINDS ARE EXPECTED TO BE BELOW 20 MPH
AT THIS TIME. MINIMAL FIRE WEATHER CONCERNS ARE ANTICIPATED FRIDAY
AND SATURDAY AS THUNDERSTORM COVERAGE WILL INCREASE AND RELATIVE
HUMIDITIES WILL TREND HIGHER...MINIMUM DAYTIME RELATIVE HUMIDITIES
WILL BE BETWEEN 20 TO 30 PERCENT BY SATURDAY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...SML
SHORT TERM...TJT
LONG TERM...ZF
AVIATION...ZF
FIRE WEATHER...TJT