Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/01/15
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
413 PM MDT SUN AUG 30 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 400 PM MDT SUN AUG 30 2015
AT PRESENT TIME ...STILL BARELY UNDER THE INFLUENCE OF A STRONG/VERY
WARM AND MOSTLY DRY POSITIVE TILT UPPER RIDGE. 700-500 MB RIDGE AXIS
IS NOW SHIFTED EAST OF THE FRONT RANGE AS PER LATEST RAP MODEL WITH
FLOW ALOFT BECOMING WEST-SOUTHWESTERLY. UPSTREAM OVER UTAH/WESTERN
WYOMING...STRONGER SWLY FLOW ALOFT WITH AN 80-90KT JET CORE IS
PROGGED TO SLOWLY TRANSLATE EASTWARD OVER NORTHERN COLORADO NEXT 24
HOURS. MID/HIGH-LEVEL MOISTURE ALIGNED WITH THIS JET WILL SPREAD
OVER NORTH CENTRAL COLORADO TONIGHT AND NORTHEAST COLORADO ON
MONDAY. MODEL CROSS SECTIONS AND SOUNDINGS SHOW CONDENSATION LEVELS
LOWERING OVER THE HIGH COUNTRY AS A BAND OF SHOWERS AND T-STORMS
ALIGNED WITH A WEAK MID-LEVEL PERTABATION PASSES OVER THE AREA THIS
EVENING. AT THE SAME TIME THIS DISTURBANCE LIFTS EAST-NORTHEAST
ACROSS THE REMAINDER OF THE FORECAST AREA...SHOULD SEE A WEAK SFC
COLD FRONT SLIDING SOUTH OUT OF WYOMING. PRESSURE RISES BEHIND
THE FRONT DO NOT APPEAR TO BE ALL THAT STRONG AND WITH THE PRE-
FRONTAL ENVIRONMENT AS DRY AS IT IS...ITS PROBABLY NOT UNTIL NELY
BNDRY LAYER WINDS KICK IN AFTER FRONTAL PASSAGE WHEN PRECIP CHANCES
SHOULD GO UP EAST OF THE MTNS. AT THIS TIME...THE POORLY ORGANIZED
FRONT COULD SLIP INTO THE DENVER AREA BY 15Z TOMORROW MORNING...WITH
A RE-ENFORCING SURGE OF SLIGHTLY COOLER AND WETTER NELY FLOW BY
ABOUT MIDDAY. MOSTLY CLOUDY TO OVERCAST SKIES AND SCATTERED POPS ARE
IN ORDER FOR MONDAY. ONE OTHER ISSUE...THIS FRONTAL SURGE IS LIKELY
TO USHER IN THE NEXT BATCH OF WILDFIRE SMOKE FORM WILDFIRES TO OUR
NORTH AND NORTHWEST. NWS AIR QUALITY FORECAST GUIDANCE NOT
INDICATING MUCH IN THE WAY OF SFC AND COLUMN SMOKE ALONG THE FRONT
RANGE...BUT SHOULD ANY RESTRICTION DUE TO SMOKE ITS MORE LIKELY TO
OCCUR LATE IN THE DAY. TEMPERATURES QUITE MILD TONIGHT...WHEN COOLING
OFF BY SEVERAL DEGREES TOMORROW. EXPECT MAX TEMPS ON MONDAY TO
BE NEAR TO SLIGHTLY ABOVE AVERAGE.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 400 PM MDT SUN AUG 30 2015
CLOUDS AND SHOWERS/STORMS WILL GRADUALLY CLEAR FROM WEST TO EAST
MONDAY NIGHT. ON TUESDAY SLIGHT DRYING AND WARMING WILL LEAD TO
DIURNAL CONVECTION OVER THE MOUNTAINS THAT SHOULD PROGRESS NICELY
EASTWARD INTO THE EVENING. CAPES ARE RATHER LOW UNTIL YOU GET OUT
ON THE PLAINS...COULD BE A LOW THREAT OF SEVERE WIND/HAIL OUT EAST
IN THE EVENING.
DRIER AIR COMES IN WEDNESDAY. A LITTLE WIND IN THE MOUNTAINS
SHOULD PEAK TUESDAY NIGHT...BUT ENOUGH LEFT WEDNESDAY FOR ELEVATED
FIRE DANGER ESPECIALLY IN NORTH AND MIDDLE PARKS. THERE SHOULD BE
A MINIMUM OF CONVECTION ON WEDNESDAY AND ESPECIALLY THURSDAY WITH
THE WARMING ALOFT AND DRYING.
PRETTY GOOD MODEL AGREEMENT ON THE SOUTHWEST FLOW CONTINUING
THROUGH SATURDAY...WITH JUST A LITTLE MOISTURE POSSIBLY CREEPING
IN AT LOW LEVELS ON THE PLAINS AND ALOFT FROM THE SOUTHWEST. STILL
LOOKS RELATIVELY DRY OVERALL.
SOME DISAGREEMENT ON THE STRUCTURE OF THE TROUGH OVER THE
NORTHWEST AND SHORTWAVES MOVING ACROSS THE NORTHERN ROCKIES NEXT
WEEKEND...BUT NOT BAD FOR THAT TIME RANGE. MOST OF THE IMPACT IS
HEADED NORTH OF US...BUT IT SHOULD PUSH A SURGE OF COOLER AND
MOISTER...AND POSSIBLY SMOKIER...AIR SOMETIME THIS WEEKEND. THERE
ARE ALSO HINTS OF SOME SUBTROPICAL MOISTURE COMING UP FROM THE
EASTERN PACIFIC...BUT THIS MAY STAY SOUTH AND EAST OF US. THERE
COULD BE AN UPSWING IN CONVECTION FROM SUNDAY INTO EARLY NEXT WEEK
AS THE MOISTURE INCREASES...BUT WE WILL STILL BE FIGHTING THE
STABILITY FROM THE WARMTH ALOFT. MODELS SEEM TO KEEP MOST OF THE
PRECIPITATION FURTHER SOUTH. FOR NOW THE COOLING AND SLIGHT
INCREASE IN POPS FOR SUNDAY WILL DO...MAYBE MORE AFTER
THAT...MAYBE NOT.
&&
.AVIATION...(FOR THE TAFS THROUGH 00Z MONDAY LATE AFTERNOON)
ISSUED AT 400 PM MDT SUN AUG 30 2015
VISIBILITIES HAVE IMPROVED IN THE DENVER AREA TODAY WITH LIGHT
SWLY TRANSPORT WINDS AND EFFICIENT MIXING OF THE BOUNDARY LAYER
DUE TO STRONG HEATING TODAY. LATER TONIGHT...COULD SEE A GRADUAL
SHIFT TO LIGHT NORTHERLY WINDS WHICH MAY FUNNEL DOWN SOME SMOKE
POISED JUST NORTH OF THE WYOMING LINE. BEFORE THEN SOUTH-SOUTHEAST
WINDS WILL PREVAIL AT SPEEDS GENERALLY UNDER 12KTS. MEANWHILE THIS
EVENING STILL ANTICIPATING A T-STORM OR TWO TO MOVE OFF THE FRONT
RANGE FOOTHILLS. THESE HIGH BASED AND MOSTLY DRY STORM CELLS WILL
HAVE THE POTENTIAL TO PRODUCE GUSTS IN THE 25-30KT RANGE. LATER
TONIGHT...COULD SEE A FEW MORE LIGHT RAIN SHOWERS AND PERHAPS A
T-STORM OR TWO MOVING ACROSS THE AREA IN ADVANCE OF OF A WEAK
UPPER AIR DISTURBANCE AND SURFACE COLD FRONT. LATEST INDICATIONS
POINT TO A WEAK FRONTAL SURGE IN THE METRO AREA AROUND 15Z
TOMORROW MORNING...WITH A SOMEWHAT STRONGER PUSH OF SLIGHTLY
COOLER AND MOIST AIR ON NELY WINDS OF 15 TO 25KTS AROUND 18Z.
AFTER WHICH SHOULD SEE PRECIP CHANCES RISE IN THE METRO AREA WITH
SCATTERED SHOWERS AND ISOLATED T-STORMS. IN ADDITION...THE GUSTY
POST-FRONTAL WINDS COULD USHER IN MORE WILDFIRE SMOKE WHICH COULD
POSSIBLY LOWER VSBYS TO 5-6 MILE RANGE BY LATE AFTERNOON...ASSUMING
IT DOESN/T MIX OUT WITH THE SHOWERY PRECIPITATION.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BAKER
LONG TERM...GIMMESTAD
AVIATION...BAKER
AREA FORECAST DISCUSSION
NWS NEW YORK NY
133 PM EDT SUN AUG 30 2015
.SYNOPSIS...
HIGH PRESSURE REMAINS OFFSHORE AHEAD OF AN APPROACHING TROUGH
WHICH WILL CROSS THE AREA TONIGHT. LOW PRESSURE THEN PASSES TO THE
NORTH ACROSS EASTERN CANADA ON MONDAY...SENDING A WEAK BACK DOOR
COLD FRONT THROUGH THE AREA TUESDAY MORNING. HIGH PRESSURE WILL
REMAIN IN CONTROL FOR THE REMAINDER OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MINOR CHANGES MADE TO FORECAST DATABASE TO BETTER MATCH OBSERVED
TRENDS. TEMPERATURES SLIGHTLY INCREASED ACROSS THE INTERIOR AND
TEMPERATURES ELSEWHERE WERE PRETTY MUCH ON TRACK. DEWPOINTS WERE
INCREASED SLIGHTLY AS WELL ACROSS THE COASTAL SECTIONS. POPS WERE
KEPT AT SLIGHT CHANCE FOR SHOWERS AND THUNDERSTORMS NORTH OF NYC.
MESOSCALE MODELS NOT SHOWING MUCH CONVECTION WITH HRRR MODEL
SHOWING RELATIVELY MORE CONVECTIVE COVERAGE.
THE TREND WILL BE FOR WARMER AND INCREASINGLY MORE HUMID
CONDITIONS HEADING INTO THE NEW WEEK AS A HIGH AMPLITUDE RIDGE
OVER THE WESTERN U.S. MERGES WITH THE SUB TROPICAL RIDGE ALONG
THE EASTERN SEABOARD. IN BETWEEN...A WEAKNESS ACROSS THE MID
SECTION OF THE COUNTRY WILL GRADUALLY FILL...WHILE A NORTHERN
STREAM SHORT WAVE TROF PASSES THROUGH THE AREA TONIGHT. AT THE
SURFACE...THIS WILL BE REFLECTED AS A SFC TROF OR WARM FRONT...
PRECEDED BY WEAK THERMAL FORCING. THIS FORCING COMBINED WITH
MARGINAL INSTABILITY MAY BE ENOUGH FOR AN ISOLATED SHOWER AND/OR
THUNDERSTORM THIS AFT/EVE...MAINLY NORTH AND WEST OF NYC. CLOUDS
WILL ALSO SPREAD IN FROM THE NW TODAY WITH MOSTLY CLOUDY
CONDITIONS BY AFTERNOON INLAND AND PARTY SUNNY AT THE COAST.
HIGHS WILL RANGE FROM THE MID 80S NEAR THE COAST...TO AROUND 90
INLAND.
THERE IS A MODERATE RISK FOR THE DEVELOPMENT OF RIP CURRENTS
TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
AFOREMENTIONED TROF/WARM FRONT MOVES THROUGH TONIGHT WITH GRADUAL
CLEARING FROM NW TO SE BY MORNING. THE UPPER LEVEL RIDGE BEGINS TO
EXPAND EASTWARD ON MON WITH WARMING TEMP PROFILES ALOFT AND A
GUSTY W/SW FLOW IN THE AFT. THIS WILL ALLOW FOR HIGHS A FEW
DEGREES WARMER THAN ON SUN...WITH READINGS TOPPING OUT IN THE
LOWER 90S INLAND.
A WEAK BACK DOOR COLD FRONT THEN PASSES THROUGH MON NIGHT AS LOW
PRESSURE PASSES WELL TO THE NORTH AND EAST ACROSS THE CANADIAN
MARITIMES. NOT MUCH RELIEF THOUGH FOR TUE WITH PERHAPS A DEGREE
OR TWO SHAVED OFF OF MON HIGHS. LOWS WILL RANGE FROM THE LOWER TO
MID 60S INLAND...TO 70 TO 75 NYC METRO. THESE READINGS ARE STILL
WELL ABOVE NORMAL. IT WILL ALSO BE MUGGY WITH DEW POINTS WELL INTO
THE 60S. HEAT INDEX VALUES LOOK TO REMAIN BELOW ADVISORY CRITERIA
AT THIS TIME.
WINDS BRIEFLY GO NW TUE MORNING BEHIND THE COLD FRONT...BUT THEN
RETURN FROM THE S BY AFT AS THE FRONT LIFTS NORTHWARD AND
DISSIPATES NEARBY. SUBSIDENCE ALOFT WILL PUT A CAP ON ANY
CONVECTION DURING THIS TIME PERIOD.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
THE MAIN THEME OF THE LONG TERM PERIOD WILL BE THE CONTINUATION OF
HEAT AND HUMIDITY ACROSS THE REGION.
MODELS ARE IN GOOD AGREEMENT WITH THE H5 PATTERN ACROSS NORTH
AMERICA INTO THE MIDDLE OF THE WEEK AS AN UPPER LEVEL RIDGE
OUT WEST MERGES WITH THE SUB TROPICAL RIDGE OVER THE WESTERN
ATLANTIC. THIS WILL RESULT IN DRY AND UNSEASONABLY WARM WEATHER
THROUGH THU POSSIBLY FRI. THIS WILL DEPEND ON THE TIMING OF THE
NEXT COLD FRONT MOVING ACROSS WHICH IS CURRENTLY UNCERTAIN DUE TO
DIFFERENCES THAT DEVELOP IN THE H5 FLOW DURING THE LATTER PORTION
OF THE WEEK. COULD SEE A FEW SHOWERS OR TSTMS WITH THE FRONTAL
PASSAGE WHICH IS CURRENTLY SLATED FOR FRIDAY...FOLLOWED BY DRY
CONDITIONS AND COOLER BUT STILL ABOVE NORMAL TEMPS FOR THE
WEEKEND.
HIGHS WILL GENERALLY RANGE IN THE UPPER 80S TO LOWER 90S ACROSS THE
AREA THROUGH MUCH OF THE WEEK...THE EXCEPTION FRI/SAT WITH THE
FRONTAL BOUNDARIES IN/THROUGH THE AREA. HEAT INDICES ARE EXPECTED
TO BE CLOSE TO THE AMBIENT AIR TEMP AND ARE NOT CURRENTLY EXPECTED
TO REACH 95 DEGREES IN NYC THROUGH WED.
&&
.AVIATION /17Z SUNDAY THROUGH THURSDAY/...
A WEAK TROUGH OF LOW PRESSURE WILL CROSS THE TRI-STATE THIS
AFTERNOON AND EVENING...THEN STALL OUT SOUTH OF LONG ISLAND INTO
MONDAY.
VFR THROUGH THE TAF PERIOD.
SEABREEZES ON TRACK FOR ALL TERMINALS EXCEPT KSWF/KTEB AND
PROBABLY KEWR. ALREADY THROUGH CT TERMINALS/KISP/KJFK. QUESTION
IS TIMING FOR REMAINDER OF TERMINALS. ISOLATED GUSTS TO AROUND 15
KT POSSIBLE AT NYC METRO TERMINALS THIS AFTERNOON AS WELL.
WINDS BECOME SW AT UNDER 10 KT AT CITY TERMINALS TONIGHT AND
LIGHT AND VARIABLE ELSEWHERE. WSW- WNW WINDS AT AROUND 10 KT
DEVELOP BY LATE MONDAY MORNING- EARLY MONDAY AFTERNOON. WIND
SPEEDS COULD INCREASE TO AROUND 15 KT AT KJFK TOWARDS THE END OF
THE TAF PERIOD.
AN ISOLATED SHOWER OR THUNDERSTORM CANNOT BE RULED OUT THE LOWER
HUDSON VALLEY THIS AFTERNOON/EARLY THIS EVENING. HAVE INCLUDED A
VCSH AT KSWF TO REFLECT.
.OUTLOOK FOR 18Z MONDAY THROUGH FRIDAY...
.MONDAY AFTERNOON...VFR. WSW-W WINDS G15-20KT POSSIBLE.
.MONDAY NIGHT-WEDNESDAY NIGHT...VFR. AFTERNOON SEABREEZES
PROBABLE EACH AFTERNOON.
.THURSDAY...MOST LIKELY VFR. ISOLATED SHOWERS/THUNDERSTORMS
POSSIBLE. AFTERNOON SEABREEZES PROBABLE.
.THURSDAY NIGHT...VFR.
.FRIDAY...MOST LIKELY VFR. E WINDS G15-20KT POSSIBLE. ISOLATED-
SCATTERED SHOWERS/THUNDERSTORMS POSSIBLE.
&&
.MARINE...
FORECAST WINDS AND SEAS CONTINUE TO REMAIN ON TRACK.
A RELATIVELY QUIET PERIOD WITH SUB-SCA CONDITIONS WILL FEATURE
LATE AFT/EARLY EVE ENHANCEMENT OF THE SW FLOW FROM THE NY BIGHT
EAST ALONG THE OCEAN WATERS. THESE WINDS MAY GUSTS TO AROUND 20
KT WITH SEAS AS HIGH AS 4 FT. HIGH PRESSURE WILL THEN BUILD
ACROSS THE WATERS ON TUE WITH TRANQUIL CONDITIONS THROUGH THU.
&&
.HYDROLOGY...
NO SIGNIFICANT RAINFALL IS FORECAST THROUGH THE UPCOMING WEEK.
&&
.TIDES/COASTAL FLOODING...
WITH A RECENT FULL MOON...BRIEF MINOR INUNDATION IS POSSIBLE
DURING THE TIMES OF HIGH TIDE ACROSS THE TYPICALLY VULNERABLE
COASTAL LOCALES INTO THE START OF THE WORK WEEK.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...DW
NEAR TERM...JM/DW
SHORT TERM...DW
LONG TERM...DW/24
AVIATION...MALOIT
MARINE...JM/DW/24
HYDROLOGY...DW
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS KEY WEST FL
944 PM EDT MON AUG 31 2015
.DISCUSSION...
KBYX RADAR SHOWS NO ACTIVE PRECIPITATION ECHOES WITHIN THE KEYS
SERVICE AREA...A MARKED DOWNWARD TREND OVER THE GULF WATERS FROM
EARLIER THIS EVENING. SKIES ARE PARTLY CLOUDY AND WINDS HAVE
SLACKENED SIGNIFICANTLY. TEMPERATURES ALONG THE ISLAND CHAIN ARE IN
THE MID 80S AT THIS HOUR.
THE LATE EVENING LOCAL SOUNDING SHOWS THE LIGHT WINDS EXTENDING TO
ABOUT 4000 FEET...WITH MORE MODERATE WINDS FROM THE SOUTHWEST/SOUTH
EXTENDING TO THE MID LEVELS. THIS PROFILE WILL DEEPEN FROM THE
SOUTHEAST OVER THE NEXT COUPLE OF HOURS. HRRR GRAPHICS SUGGEST A LOW
LEVEL SURGE THROUGH THE EARLY MORNING HOURS...POSSIBLY FOCUSING
SHOWERS AND A FEW THUNDERSTORMS. BUT WITH SLIGHTLY DRIER AIR
ALOFT...A SMALL AREA OF SLIGHTLY DRIER AIR IMMEDIATELY UPSTREAM PER
CIMSS PRECIPITABLE WATER LOOP...AND THE GENERAL LACK OF ACTIVITY
CURRENTLY IN THAT AREA PER KBYX RADAR...DECIDED TO TRIM OUR
PROBABILITY OF MEASURABLE PRECIPITATION THROUGH THE REMAINDER OF THE
FIRST PERIOD. THAT ZONE UPDATE WAS RECENTLY ISSUED.
&&
.MARINE...
WINDS WILL BE TRIMMED BY A FEW KNOTS OVER THE BULK OF THE KEYS MARINE
SERVICE AREA...BUT WILL GIVE A BIT OF CREDIT TO A MINOR SURGE FOR THE
NEXT FEW HOURS ADVERTISED BY THE HRRR. A MORE SIGNIFICANT DOWNWARD
WIND SPEED ADJUSTMENT IS NECESSARY IN THE OFFSHORE GULF WATERS IN THE
IMMEDIATE TERM. AS WITH THE ZONES...THE EXPECTED COVERAGE OF
SHOWERS/TSTMS WILL BE TRIMMED THROUGH THE OVERNIGHT PERIOD...DOWN TO
ISOLATED.
&&
.AVIATION...VFR CONDITIONS WILL PREVAIL AT BOTH THE KEY WEST AND
MARATHON TERMINALS OVERNIGHT. A FEW PASSING SHOWERS ARE POSSIBLE
BRINGING BRIEF MVFR CONDITIONS. HOWEVER...THE CONFIDENCE IS NOT HIGH
ENOUGH TO WARRANT INCLUSION IN THE TERMINAL FORECAST. SURFACE WINDS
WILL BE MAINLY FROM THE SOUTHEAST BETWEEN 5 AND 10 KNOTS...BUT COULD
BE LIGHT AND VARIABLE AT TIMES.
&&
.KEY WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GM...NONE.
&&
$$
PUBLIC/MARINE.........04
AVIATION/NOWCASTS.....DEVANAS
DATA COLLECTION.......BWC
VISIT US ON THE WEB AT WEATHER.GOV/KEY
FOLLOW US ON FACEBOOK AND TWITTER AT...
WWW.FACEBOOK.COM/NWSKEYWEST
WWW.TWITTER.COM/NWSKEYWEST
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
1017 AM EDT SUN AUG 30 2015
.DISCUSSION...
...HEAVY RAIN AND FLOODING THREAT CONTINUES THROUGH MONDAY...
TODAY...TROPICAL AIR MASS IN PLACE WITH GPS PRECIPITABLE WATER
VALUES AT LEAST 2.2 TO 2.3 INCHES. THE 12Z SURFACE ANALYSIS SHOWED
AN INVERTED TROUGH (REMNANTS OF ERIKA) EXTENDING FROM THE LOWER KEYS
TO SOUTH FLORIDA. THIS LOW LEVEL TROUGH LIKELY EXTENDED EVEN FARTHER
NORTHWARD TO NEAR CAPE CANAVERAL SINCE THE BUOYS OFFSHORE WERE
SHOWING BREEZY SOUTHEAST FLOW WHILE OUR NORTHERN LAND AREAS WERE
LIGHT IN THE EARLY MORNING HOURS.
NORTHERN BAHAMA CONVERGENCE LINES AND COASTAL CONVERGENCE HAVE LED
TO A FEW ROUNDS OF SHOWERS/STORMS ALONG THE COAST THIS MORNING.
EXPECT THIS WILL CONTINUE INTO THE AFTERNOON AS SATELLITE WAS
SHOWING A LARGER SCALE OUTFLOW BOUNDARY APPROACHING GRAND BAHAMA
FROM THE SOUTH...WHICH WILL LIKELY GENERATE SOME LARGER CLUSTERS OF
STORMS.
THE INTERIOR HAS BEEN BRUSHED BY A FEW SHOWERS THIS MORNING AND
THERE WERE LIKELY SOME OUTFLOW BOUNDARIES PRESSING INLAND FROM THE
COASTAL CONVECTION. EXPECT WITH THE HIGH MOISTURE IN PLACE AND
MODEST HEATING THROUGH LATE MORNING THERE WILL BE A RATHER LARGE
CLUSTER OF STORMS DEVELOPING. THE HRRR MODEL HAS BEEN SHOWING THIS
BLOWUP LIFTING NORTHWARD UP THE INTERIOR WITH SOME AFFECTING THE
COASTAL COUNTIES TOO.
THIS SETUP ALONG WITH SOME DIVERGENCE ALOFT WILL LEAD TO A HIGH
COVERAGE OF RAINFALL ACROSS THE ENTIRE AREA. LOCATIONS THAT RECEIVE
SEVERAL ROUNDS OF SHOWERS/STORMS COULD HAVE RAINFALL TOTALS 2-3
INCHES...SO FLOOD WATCH IN PLACE LOOKS GOOD.
WE COULD JUST ABOUT RING THE BELL TODAY AND GO WITH 100 PERCENT
POPS. DO NOT PLAN ANY SIGNIFICANT CHANGES TO THE PREVIOUS FORECAST
PACKAGE THOUGH...WHICH SHOWS ANOMALOUSLY HIGH 90 POPS. WITH ALL THE
RAIN AND CLOUDS...TEMPS WILL HAVE TROUBLE REACHING THE UPPER 80S AND
MIGHT HAVE TO TWEAK READINGS DOWN A FEW DEGREES HERE AND THERE.
&&
.AVIATION...NO CHANGES TO PREVIOUS DISCUSSION
HIGH COVERAGE OF SHOWERS AND STORMS EXPECTED ACROSS THE REGION TODAY
WITH A VERY MOIST TROPICAL AIRMASS IN PLACE. GREATEST COVERAGE AND
BEST CHANCE FOR REDUCTIONS TO IFR/MVFR CONDS WILL BE ALONG THE COAST
IN THE MORNING...THEN EXPECT WIDESPREAD SHOWER/SCT STORM COVERAGE
ACROSS THE ENTIRE AREA INTO THE AFT. RAIN CHANCES DECREASE ACROSS
THE INTERIOR PAST MIDNIGHT WITH SHOWERS AND STORMS REMAINING LIKELY
ALONG THE COAST.
&&
.MARINE...
TODAY/TONIGHT...POOR TO HAZARDOUS BOATING CONDITIONS WILL OCCUR AS
REMNANT LOW PRESSURE TROUGH FROM ERIKA...NEAR SOUTH FL...PRODUCES
GUSTY SOUTHEAST WINDS. WIND SPEEDS 15 TO 20 KNOTS WILL BUILD SEAS UP
TO 6-7 FEET OFFSHORE. IN ADDITION WIDESPREAD SHOWERS AND SCATTERED
STORMS WITH GUSTY WINDS WILL CONTINUE TO DEVELOP AND MOVE NORTH TO
NORTHWEST OVER THE WATERS.
THOUGH THE STORMY WEATHER CONDITIONS SHOULD KEEP MOST SMALL CRAFT IN
PORT...THERE IS A SMALL CRAFT ADVISORY IN EFFECT FOR THE TREASURE
COAST WATERS AND OFFSHORE BREVARD COUNTY...WITH EXERCISE CAUTION
STATEMENTS ELSEWHERE.
&&
.HYDROLOGY...NO CHANGE TO THE PREVIOUS DISCUSSION
RAINFALL TOTALS AROUND TO 2 TO 4 INCHES ARE FORECAST ACROSS EAST
CENTRAL FLORIDA THROUGH MONDAY NIGHT WITH LOCALLY HIGHER AMOUNTS UP
TO 5 TO 6 INCHES POSSIBLE. MAIN CONCERNS FOR ANY FLOODING WILL BE
ALONG THE COAST FROM BREVARD SOUTHWARD WHERE ANY PERSISTENT RAIN
BANDS CAN DEVELOP. ALSO...SHINGLE CREEK AT CAMPBELL (SHIF1) IS ONLY
ABOUT 0.2 FEET BELOW ACTION STAGE. ANY ADDITIONAL HEAVY RAINFALL
TOTALS ACROSS THE SHINGLE CREEK BASIN TODAY MAY PRODUCE MINOR
FLOODING AT THIS SITE AND WILL HAVE TO BE MONITORED CLOSELY.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...FLOOD WATCH THROUGH MONDAY EVENING FOR COASTAL VOLUSIA COUNTY-
INDIAN RIVER-INLAND VOLUSIA COUNTY-MARTIN-NORTHERN BREVARD
COUNTY-NORTHERN LAKE COUNTY-OKEECHOBEE-ORANGE-OSCEOLA-
SEMINOLE-SOUTHERN BREVARD COUNTY-SOUTHERN LAKE COUNTY-ST.
LUCIE.
AM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR SEBASTIAN
INLET TO JUPITER INLET 0-20 NM-SEBASTIAN INLET TO JUPITER
INLET 20-60 NM-VOLUSIA-BREVARD COUNTY LINE TO SEBASTIAN
INLET 20-60 NM.
&&
$$
FORECASTS...LASCODY
IMPACT WX....SEDLOCK/VOLKMER
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
744 AM EDT SUN AUG 30 2015
.SYNOPSIS...
A STRONG UPPER LEVEL DISTURBANCE WILL LIFT NORTH THROUGH GEORGIA
AND THE CAROLINAS THROUGH TONIGHT. ON THE PERIPHERY OF ATLANTIC HIGH
PRESSURE...A WEAK TROUGH OF LOW PRESSURE WILL MEANDER OVER THE
SOUTHEAST MOST OF THIS WEEK. LATE THIS WEEK INTO NEXT WEEKEND...LOW
PRESSURE WILL DEVELOP OVER THE ATLANTIC WHILE WEAK INLAND HIGH
PRESSURE EXPANDS SOUTH AND EAST INTO THE REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
THROUGH TONIGHT...AN ANOMALOUS MID AND UPPER LOW OVER THE WESTERN
FLORIDA PANHANDLE AT DAYBREAK WILL LIFT NE AND GRADUALLY OPEN INTO
A WAVE AS IT HEADS TOWARD THE SOUTHERN APPALACHIANS. THIS FEATURE
WILL RESULT IN AN STEADY INFLUX OF DEEP MOISTURE WITH PWATS ABOVE
2 INCHES INTO SOUTHERN SC AND SE GA. IT ALSO ARRIVES WITH DECENT
FORCING FOR ASCENT IN RESPONSE TO A 40-45 JET MAX AT 500 MB AND
STEADY UPPER DIVERGENCE AS IT PASSES OVERHEAD. THIS WILL CAUSE AT
LEAST SCATTERED TO NUMEROUS COVERAGE OF RAINFALL WITH POCKETS OF
DEEP CONVECTION LIKELY ALONG WITH OCCASIONAL DOWNPOURS.
A COMPLEX MESOSCALE WITH UNSEASONABLY STRONG LOW LEVEL MOISTURE
GRADIENTS LAST NIGHT HAS GIVEN WAY TO RAINS MARCHING NORTH WITH SOME
THUNDER ALONG COASTAL AND SOUTHERN ZONES. THERE SHOULD BE A GOOD
POTENTIAL FOR LOCALLY HEAVY RAINFALL TODAY...THE GFS AND RECENTLY
HIGH RESOLUTION OUTPUTS FROM BOTH THE HRRR AND NSSL ARW MODELS
SUGGEST THERE COULD ALSO BE A LULL IN HEAVY RAIN POTENTIAL NORTH
OF THE SAVANNAH RIVER THIS AFTERNOON BETWEEN TSTMS DEVELOPING
AHEAD OF THE EJECTING LOW ACROSS EAST CENTRAL GEORGIA/CSRA AND
COASTAL CONVERGENCE CONTINUING TO THE SOUTH OF THE SAVANNAH
RIVER. MODELS SUGGEST STEEPENING INLAND LAPSE RATES ALONG WITH AT
LEAST 25 KT OF 0-6 KM BULK SHEAR ACROSS OUR INLAND ZONES THIS
AFTERNOON AND EVENING. INLAND AREAS TO WEST OF I-95 COULD SEE A
WINDOW FOR ISOLATED STRONG TO SEVERE TSTMS AS UPPER LEVEL FORCING
INCREASES AHEAD OF VERY WELL DEFINED DRIER SLOT BETWEEN 850 MB AND
500 MB. WOULD NOT BE SURPRISED TO SEE CONVECTION ORGANIZE LATER
TODAY TO THE WEST OF I-95 AND WE WILL HAVE TO MONITOR FOR ISOLATED
SEVERE WEATHER POTENTIAL...ESPECIALLY ALONG TO THE W OF I-95.
TONIGHT...CONTINUED COMPLEXITIES AS THE UPPER LOW EJECTS BY AND
DRYING MID LEVELS EVENTUALLY SHUT DOWN RAINS ALONG AND WEST OF
I-95 BUT ATTENTION TURNS TO HEAVY RAIN POTENTIAL ALONG COASTAL
SOUTH CAROLINA AFTER MIDNIGHT AS STRONG UPPER DIVERGENCE WILL
ENHANCE LIFT WHILE DEEP LAYERED MOISTURE AND SIGNIFICANT LOW LEVEL
MOISTURE CONVERGENCE ENHANCES CONVECTIVE RAINS. WE RAMP POPS UP
TO CATEGORICAL ALONG THE CENTRAL SOUTH CAROLINA COAST LATE.
LOCALLY HEAVY RAINS...PERHAPS ISOLATED EXCESSIVE RAINFALL MAY
OCCUR ALONG CHARLESTON COUNTY IF THE LATEST MODEL GUIDANCE PANS
OUT.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
MONDAY MORNING...THE UPPER TROUGH AND ASSOCIATED FORCING FOR ASCENT
WILL HAVE ADVANCED NORTH/NORTHEAST OF THE REGION. HOWEVER...FOCUSED
LOW/MID LEVEL MOISTURE TRANSPORT AND AN ASSOCIATED PLUME OF PWATS 2
TO 2.25 INCHES WILL CONTINUE TO PUSH ONSHORE ESPECIALLY INTO SOUTH
CAROLINA COUNTIES. GIVEN ABOVE-AVERAGE MODEL AGREEMENT REGARDING
THIS SCENARIO...MONDAY MORNING FEATURES LIKELY/CATEGORICAL POPS
ALONG/EAST OF I-95...HIGHEST INTO SC COUNTIES INCLUDING THE
CHARLESTON TRI-COUNTY REGION. GIVEN ELEVATED PWATS AND HIGH
PRECIPITATION EFFICIENCY...INTRODUCED A MENTION OF HEAVY RAIN INTO
AREAS ALONG/EAST OF I-95. ALSO...AN ELEVATED HIGH TIDE WILL OCCUR
BETWEEN 900 AND 1100 AM...AND IF/WHERE HEAVY RAIN IS FALLING WITHIN
COASTAL COUNTIES LOCALIZED FLOODING WILL BE POSSIBLE. THIS POTENTIAL
INCLUDED DOWNTOWN CHARLESTON.
MONDAY AFTERNOON...POPS BECOME LESS WELL DEFINED DUE TO THE UNKNOWN
IMPACT OF MORNING SHOWERS/THUNDERSTORMS AND DUE TO THE POTENTIAL FOR
SUBTLE DRYING TO OCCUR ACROSS NORTHERN/INLAND COUNTIES. EARLY
AFTERNOON POPS ARE TAPERED FROM LIKELY NEAR THE COAST TO CHANCE
INLAND.
OTHERWISE...DUE TO CLOUDS AND PRECIPITATION...MONDAY HIGH TEMPS IN
THE LOWER/MID 80S SHOULD BE COMMON...SLIGHTLY BELOW NORMAL FOR LATE
AUGUST.
MONDAY NIGHT...A POOL OF DEEP MOISTURE WILL REMAIN FOCUSED NEAR THE
COAST AND OVER COASTAL WATERS. INLAND POPS DECREASE FROM CHANCE TO
SLIGHT CHANCE WITH TIME INLAND...WHILE POPS NEAR THE COAST REMAIN IN
THE 50-60 PERCENT RANGE...HIGHEST OVER CENTRAL/SOUTHERN COASTAL
COUNTIES. LOCALLY EXCESSIVE RAINFALL WILL REMAIN POSSIBLE NEAR THE
COAST.
THE SCENARIO APPEARS SIMILAR TUESDAY THROUGH WEDNESDAY. WHILE
SLIGHTLY DRIER AIR COULD INFILTRATE NORTHERN/INLAND COUNTIES...A
POOL OF ENHANCED MOISTURE WILL REMAIN TRAPPED BENEATH A BUILDING
UPPER RIDGE...ESPECIALLY OVER SOUTHERN COUNTIES AND ACROSS ADJACENT
COASTAL WATERS. POPS ARE DISTRIBUTED ACCORDINGLY...WITH
HIGHEST/LIKELY POPS ACROSS SOUTHERN COUNTIES. HIGH PWATS AND WEAK
STEERING FLOW WILL CONTINUE TO SUPPORT THE POTENTIAL FOR LOCALLY
HEAVY RAINFALL. TEMPS WILL DEPEND ON CLOUD/PRECIPITATION COVERAGE.
HIGHS IN THE MID 80S WILL REMAIN COMMON BOTH DAYS. HOWEVER...
TEMPERATURES COULD REMAIN IN THE LOWER 80S IF/WHERE CLOUDS/SHOWERS
PERSIST...WHILE TEMPERATURES COULD RECOVER INTO THE UPPER 80S WHERE
PRECIPITATION COVERAGE IS REDUCED...ESPECIALLY INLAND.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
UNTIL LATE WEEK...SUFFICIENT MOISTURE WILL PERSIST BENEATH AN UPPER
RIDGE TO SUPPORT AT LEAST SCATTERED SHOWERS/THUNDERSTORMS ESPECIALLY
DURING THE MIDDAY/EVENING HOURS AND ALONG THE COAST/OVER ADJACENT
COASTAL WATERS DURING THE LATE NIGHT/EARLY MORNING HOURS. LATE THIS
WEEK INTO NEXT WEEKEND OFF THE MID ATLANTIC COAST NEAR 37N/70W...AN
AMPLIFYING UPPER TROUGH WILL PROMOTE SURFACE CYCLOGENESIS...AND THIS
SYSTEM WILL EVOLVE INTO DEEP LAYERED/CUT-OFF LOW PRESSURE. THIS
SYSTEM WILL DRIVE THE UPPER RIDGE WELL SOUTH OF THE REGION...BUT THE
IMPACTS ON SENSIBLE WEATHER REMAIN UNCERTAIN. IF THE ATLANTIC TROUGH
PHASES WITH THE UPPER LOW ALONG THE GULF COAST...AN UNSETTLED
PATTERN COULD DEVELOP OVER THE REGION. HOWEVER...IF THE SYSTEMS
REMAIN SEPARATE...SOMEWHAT DRIER AIR COULD SPREAD INTO THE REGION
FROM THE NORTH/NORTHWEST. THUS...POPS REMAIN PRETTY CLOSE TO
NORMAL. TEMPERATURES SHOULD REMAIN CLOSE TO NORMAL THROUGH THE
PERIOD...AND FORECAST TEMPERATURES REMAIN BELOW 90F THROUGH NEXT
WEEKEND. HOWEVER...THE PROBABILITY FOR WARMER TEMPS INTO THE LOWER
90S COULD INCREASE LATE WEEK INTO NEXT WEEKEND ESPECIALLY IF DRIER
AIR CIRCULATES INTO THE REGION.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
THE OVERALL PICTURE REMAINS VERY UNSETTLED THROUGH TONIGHT WITH
THE SYNOPTIC PATTERN FAVORING PERIODIC SHOWERS WITH A CHANCE
OF TSTMS. GUIDANCE HINTS THAT MORE ACTIVE PERIODS OF CONVECTION
THIS AFTERNOON MAY LOWER CIGS AND VSBYS INTO MVFR RANGE WITH
POCKETS OF IFR VSBYS POSSIBLE UNDER THE HEAVIER CONVECTIVE
ELEMENTS WHERE DOWNPOURS ARE OCCURRING.
TONIGHT...RAINS ARE EXPECTED TO DIMINISH OVERNIGHT AT KSAV BUT
INCREASE AT KCHS AFTER 08Z AS DEEP MOISTURE PILES INTO THE
SOUTH CAROLINA COAST...ENHANCED BY GOOD LOW LEVEL SPEED
CONVERGENCE AND A RIBBON OF UPPER LEVEL FORCING FOR ASCENT.
EXTENDED AVIATION OUTLOOK THROUGH THURSDAY...PERIODS OF FLIGHT
RESTRICTIONS APPEAR LIKELY THROUGH EARLY WEEK...ESPECIALLY IN
SHOWERS/THUNDERSTORMS. VFR SHOULD BECOME MORE COMMON MID TO LATE
WEEK.
&&
.MARINE...
ONSHORE FLOW WILL INCREASE ACROSS GEORGIA WATERS LATER TODAY AND
TONIGHT...PERHAPS 15-20 KT WITH SOME HIGHER GUSTS POSSIBLE FROM
GRAYS REEF AND BEYOND. THIS COULD ASSIST SEAS BUILDING TO SMALL
CRAFT ADVISORY LEVELS OVER GEORGIA WATERS FROM 20-60 NM LATER
TONIGHT. WIDESPREAD RAINS AND OCCASIONAL TSTMS OVER THE WATERS
THROUGH TONIGHT WILL LOWER VSBYS BELOW 3 NM AT TIMES AND PRODUCE
LOCALLY GUSTY WINDS...ESPECIALLY TONIGHT. WE HAVE HELD OFF ON
ISSUING AN SCA FOR OUTER WATERS JUST YET UNTIL WE GET A BETTER
HANDLE ON CONVECTION PATTERNS WHICH MAY DISRUPT WINDS BUT
LOCALLY ENHANCE WAVES.
PERSISTENT SE WINDS COULD USHER A 6 FT SWELL INTO GA COASTAL WATERS
BEYOND 20-40 NM MONDAY. THIS SCENARIO REMAINS UNCERTAIN...THUS WILL
NOT YET RAISE A SMALL CRAFT ADVISORY. OTHERWISE...SOUTHEAST WINDS
SHOULD REMAIN CAPPED AT 15-20 KT AND SEAS SHOULD REMAIN 3-5 FT
THROUGH TUESDAY. MID TO LATE WEEK...A WEAKENING ONSHORE PRESSURE
GRADIENT WILL TRANSLATE TO LIGHTER WINDS...FREQUENTLY 10 KT OR
LESS...AND SEAS SHOULD SUBSIDE TO 1-3 FT...HIGHEST BEYOND 20 NM.
MEANWHILE...SHOWERS/THUNDERSTORMS WILL REMAIN COMMON OVER COASTAL
WATERS THROUGH THIS WEEK. STRONGER THUNDERSTORMS COULD PRODUCE GUSTY
WINDS...FREQUENT LIGHTNING AND POOR VISIBILITY IN VERY HEAVY
RAINFALL. MARINERS SHOULD REMAIN ALERT FOR SPECIAL MARINE WARNINGS
AND MARINE WEATHER STATEMENTS.
MARINERS ARE ADVISED THAT SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS WILL OCCUR EACH OF THE NEXT SEVERAL DAYS AND NIGHTS.
SOME OF THESE STORMS WILL PRODUCE FREQUENT LIGHTNING...HEAVY RAINS
REDUCING VISIBILITIES TO NEAR ZERO AT TIMES AND WIND GUSTS UP TO
AT LEAST 30 KT WITH BRIEFLY HIGHER SEAS. REMEMBER TO MONITOR OUR
FORECASTS AND YOUR NOAA WEATHER RADIO.
CONDITIONS WON/T BE MUCH DIFFERENT SUNDAY WITH ONSHORE
WINDS...SMALL SWELLS AND ASTRONOMICAL INFLUENCES FROM THE PERIGEE
AND FULL MOON. THIS WILL RESULT IN AT LEAST A MODERATE RISK OF RIP
CURRENTS AT AREA BEACHES.
WHILE WE START TO LOSE THE ASTRONOMICAL INFLUENCES AS WE GO THROUGH
THE WEEK...THERE IS STILL AN ONSHORE WIND COMPONENT AND POSSIBLE
SMALL SWELLS TO GENERATE A POSSIBLE ELEVATED RISK DURING AT LEAST THE
EARLY PART OF THE WEEK.
RIP CURRENTS...A HIGH RISK OF RIP CURRENTS AT TYBEE ISLAND TODAY
GIVEN SWELL PERIODS WERE NOW OVER 10 SECONDS WITH OTHERWISE
FAVORABLE CONDITIONS INCLUDING PERSISTENCE FROM SATURDAY. SOUTH
CAROLINA COAST WILL HAVE A MODERATE RISK THROUGH THIS EVENING...
OTHERWISE AN ELEVATED RISK FOR RIP CURRENTS COULD PERSIST INTO
EARLY THIS WEEK.
&&
.TIDES/COASTAL FLOODING...
THROUGH TONIGHT...ASTRONOMICAL INFLUENCES DUE TO THE PERIGEAN
SPRING TIDE PLUS ONSHORE WINDS WILL MAINTAIN ELEVATED HIGH TIDE
LEVELS ALONG THE COAST. WHILE WE WILL BE CLOSE TO POSSIBLE
SHALLOW COASTAL FLOODING IN CHARLESTON HARBOR WITH THE MORNING
HIGH TIDE TODAY...A BETTER CHANCE FOR SHALLOW SALT WATER FLOODING
EXISTS WITH THE EVENING HIGH TIDE. COASTAL FLOOD ADVISORIES WILL
LIKELY BE REQUIRED FOR AT LEAST PARTS OF THE SC COAST...AND WE/LL
BE CLOSE TO THE ADVISORY CRITERIA FURTHER SOUTH...INCLUDING THE
SAVANNAH AREA. ALSO OF NOTE...PERIODS OF SHOWERS/THUNDERSTORMS
WITH HEAVY RAIN ARE EXPECTED. IF HEAVY RAIN FALLS IN COASTAL
COMMUNITIES...INCLUDING DOWNTOWN CHARLESTON AND/OR DOWNTOWN
SAVANNAH AROUND THE TIMES OF HIGH TIDE...MORE SIGNIFICANT FLOODING
IS POSSIBLE.
MONDAY AND TUESDAY...LINGERING ASTRONOMICAL INFLUENCES AND
PERSISTENT ONSHORE FLOW COULD PRODUCE A COUPLE OF ADDITIONAL CYCLES
OF SHALLOW SALT WATER FLOODING WITH THE NIGHTTIME HIGH
TIDE...ESPECIALLY ALONG THE SOUTH CAROLINA COAST. ALSO OF CONCERN...
PERIODS OF HEAVY RAIN ARE POSSIBLE ALONG THE COAST EARLY THIS
WEEK...AND LOCALIZED FLOODING IS POSSIBLE ESPECIALLY IF HEAVY RAIN
FALLS AROUND THE TIMES OF HIGH TIDE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...HIGH RISK FOR RIP CURRENTS THROUGH THIS EVENING FOR GAZ117-119-
139-141.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...SPR
LONG TERM...SPR
AVIATION...
MARINE...SPR
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
457 AM EDT SUN AUG 30 2015
.SYNOPSIS...
A STRONG UPPER LEVEL DISTURBANCE WILL LIFT NORTH THROUGH GEORGIA
AND THE CAROLINAS THROUGH TONIGHT. ON THE PERIPHERY OF ATLANTIC HIGH
PRESSURE...A WEAK TROUGH OF LOW PRESSURE WILL MEANDER OVER THE
SOUTHEAST MOST OF THIS WEEK. LATE THIS WEEK INTO NEXT WEEKEND...LOW
PRESSURE WILL DEVELOP OVER THE ATLANTIC WHILE WEAK INLAND HIGH
PRESSURE EXPANDS SOUTH AND EAST INTO THE REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
PRE-DAWN...QUITE A SURGE OF DEEP MOISTURE HAS BEEN ONGOING ACROSS SE
GEORGIA OVERNIGHT AS LOW LEVEL FLOW HAS VEERED TO SE OFF THE GEORGIA
COASTAL ENHANCING STRONG CONVERGENCE ALONG THE SAVANNAH RIVER AND
PUSHING SHOWERS AND TSTMS NORTH INTO SOUTHERN AND COASTAL SOUTH
CAROLINA. A CLUSTER OF INTENSE RAINFALL PASSING THROUGH EASTERN
CHATHAM COUNTY BUT IT SHOULD MOVE ALONG AND PERHAPS WEAKENING
JUST A BIT AS IT SHIFTS INTO JASPER AND BEAUFORT COUNTIES. BY
DAWN...CHANCE POPS REACHING INTO OUR FAR NW ZONES WHILE LIKELY OR
EVEN HIGHER CHANCES SOUTH OF I-16 INTO COASTAL SOUTH CAROLINA.
THROUGH TONIGHT...AN ANOMALOUS MID AND UPPER LOW OVER THE WESTERN
FLORIDA PANHANDLE AT DAYBREAK WILL LIFT NE AND GRADUALLY OPEN
INTO A WAVE AS IT HEADS TOWARD THE SOUTHERN APPALACHIANS. THIS
FEATURE WILL RESULT IN AN STEADY INFLUX OF DEEP MOISTURE WITH
PWATS ABOVE 2 INCHES INTO SOUTHERN SC AND SE GA. IT ALSO ARRIVES
WITH DECENT FORCING FOR ASCENT IN RESPONSE TO A 40-45 JET MAX AT
500 MB AND STEADY UPPER DIVERGENCE AS IT PASSES OVERHEAD. THIS
WILL CAUSE AT LEAST SCATTERED TO NUMEROUS COVERAGE OF RAINFALL
WITH POCKETS OF DEEP CONVECTION LIKELY ALONG WITH OCCASIONAL
DOWNPOURS.
A COMPLEX MESOSCALE WITH UNSEASONABLY STRONG LOW LEVEL MOISTURE
GRADIENTS LAST NIGHT HAS GIVEN WAY TO RAINS MARCHING NORTH WITH SOME
THUNDER ALONG COASTAL AND SOUTHERN ZONES. THERE SHOULD BE A GOOD
POTENTIAL FOR LOCALLY HEAVY RAINFALL TODAY...THE GFS AND RECENTLY
HIGH RESOLUTION OUTPUTS FROM BOTH THE HRRR AND NSSL ARW MODELS
SUGGEST THERE COULD ALSO BE A LULL IN HEAVY RAIN POTENTIAL NORTH
OF THE SAVANNAH RIVER THIS AFTERNOON BETWEEN TSTMS DEVELOPING
AHEAD OF THE EJECTING LOW ACROSS EAST CENTRAL GEORGIA/CSRA AND
COASTAL CONVERGENCE CONTINUING TO THE SOUTH OF THE SAVANNAH
RIVER. MODELS SUGGEST STEEPENING INLAND LAPSE RATES ALONG WITH AT
LEAST 25 KT OF 0-6 KM BULK SHEAR ACROSS OUR INLAND ZONES THIS
AFTERNOON AND EVENING. INLAND AREAS TO WEST OF I-95 COULD SEE A
WINDOW FOR ISOLATED STRONG TO SEVERE TSTMS AS UPPER LEVEL FORCING
INCREASES AHEAD OF VERY WELL DEFINED DRIER SLOT BETWEEN 850 MB AND
500 MB. WOULD NOT BE SURPRISED TO SEE CONVECTION ORGANIZE LATER
TODAY TO THE WEST OF I-95 AND WE WILL HAVE TO MONITOR FOR ISOLATED
SEVERE WEATHER POTENTIAL.
TONIGHT...CONTINUED COMPLEXITIES AS THE UPPER LOW EJECTS BY AND
DRYING MID LEVELS EVENTUALLY SHUT DOWN RAINS ALONG AND WEST OF
I-95 BUT ATTENTION TURNS TO HEAVY RAIN POTENTIAL ALONG COASTAL
SOUTH CAROLINA AFTER MIDNIGHT AS STRONG UPPER DIVERGENCE WILL
ENHANCE LIFT WHILE DEEP LAYERED MOISTURE AND SIGNIFICANT LOW LEVEL
MOISTURE CONVERGENCE ENHANCES CONVECTIVE RAINS. WE RAMP POPS UP
TO CATEGORICAL ALONG THE CENTRAL SOUTH CAROLINA COAST LATE.
LOCALLY HEAVY RAINS...PERHAPS ISOLATED EXCESSIVE RAINFALL MAY
OCCUR ALONG CHARLESTON COUNTY IF THE LATEST MODEL GUIDANCE PANS
OUT.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
MONDAY MORNING...THE UPPER TROUGH AND ASSOCIATED FORCING FOR ASCENT
WILL HAVE ADVANCED NORTH/NORTHEAST OF THE REGION. HOWEVER...FOCUSED
LOW/MID LEVEL MOISTURE TRANSPORT AND AN ASSOCIATED PLUME OF PWATS 2
TO 2.25 INCHES WILL CONTINUE TO PUSH ONSHORE ESPECIALLY INTO SOUTH
CAROLINA COUNTIES. GIVEN ABOVE-AVERAGE MODEL AGREEMENT REGARDING
THIS SCENARIO...MONDAY MORNING FEATURES LIKELY/CATEGORICAL POPS
ALONG/EAST OF I-95...HIGHEST INTO SC COUNTIES INCLUDING THE
CHARLESTON TRI-COUNTY REGION. GIVEN ELEVATED PWATS AND HIGH
PRECIPITATION EFFICIENCY...INTRODUCED A MENTION OF HEAVY RAIN INTO
AREAS ALONG/EAST OF I-95. ALSO...AN ELEVATED HIGH TIDE WILL OCCUR
BETWEEN 900 AND 1100 AM...AND IF/WHERE HEAVY RAIN IS FALLING WITHIN
COASTAL COUNTIES LOCALIZED FLOODING WILL BE POSSIBLE. THIS POTENTIAL
INCLUDED DOWNTOWN CHARLESTON.
MONDAY AFTERNOON...POPS BECOME LESS WELL DEFINED DUE TO THE UNKNOWN
IMPACT OF MORNING SHOWERS/THUNDERSTORMS AND DUE TO THE POTENTIAL FOR
SUBTLE DRYING TO OCCUR ACROSS NORTHERN/INLAND COUNTIES. EARLY
AFTERNOON POPS ARE TAPERED FROM LIKELY NEAR THE COAST TO CHANCE
INLAND.
OTHERWISE...DUE TO CLOUDS AND PRECIPITATION...MONDAY HIGH TEMPS IN
THE LOWER/MID 80S SHOULD BE COMMON...SLIGHTLY BELOW NORMAL FOR LATE
AUGUST.
MONDAY NIGHT...A POOL OF DEEP MOISTURE WILL REMAIN FOCUSED NEAR THE
COAST AND OVER COASTAL WATERS. INLAND POPS DECREASE FROM CHANCE TO
SLIGHT CHANCE WITH TIME INLAND...WHILE POPS NEAR THE COAST REMAIN IN
THE 50-60 PERCENT RANGE...HIGHEST OVER CENTRAL/SOUTHERN COASTAL
COUNTIES. LOCALLY EXCESSIVE RAINFALL WILL REMAIN POSSIBLE NEAR THE
COAST.
THE SCENARIO APPEARS SIMILAR TUESDAY THROUGH WEDNESDAY. WHILE
SLIGHTLY DRIER AIR COULD INFILTRATE NORTHERN/INLAND COUNTIES...A
POOL OF ENHANCED MOISTURE WILL REMAIN TRAPPED BENEATH A BUILDING
UPPER RIDGE...ESPECIALLY OVER SOUTHERN COUNTIES AND ACROSS ADJACENT
COASTAL WATERS. POPS ARE DISTRIBUTED ACCORDINGLY...WITH
HIGHEST/LIKELY POPS ACROSS SOUTHERN COUNTIES. HIGH PWATS AND WEAK
STEERING FLOW WILL CONTINUE TO SUPPORT THE POTENTIAL FOR LOCALLY
HEAVY RAINFALL. TEMPS WILL DEPEND ON CLOUD/PRECIPITATION COVERAGE.
HIGHS IN THE MID 80S WILL REMAIN COMMON BOTH DAYS. HOWEVER...
TEMPERATURES COULD REMAIN IN THE LOWER 80S IF/WHERE CLOUDS/SHOWERS
PERSIST...WHILE TEMPERATURES COULD RECOVER INTO THE UPPER 80S WHERE
PRECIPITATION COVERAGE IS REDUCED...ESPECIALLY INLAND.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
UNTIL LATE WEEK...SUFFICIENT MOISTURE WILL PERSIST BENEATH AN UPPER
RIDGE TO SUPPORT AT LEAST SCATTERED SHOWERS/THUNDERSTORMS ESPECIALLY
DURING THE MIDDAY/EVENING HOURS AND ALONG THE COAST/OVER ADJACENT
COASTAL WATERS DURING THE LATE NIGHT/EARLY MORNING HOURS. LATE THIS
WEEK INTO NEXT WEEKEND OFF THE MID ATLANTIC COAST NEAR 37N/70W...AN
AMPLIFYING UPPER TROUGH WILL PROMOTE SURFACE CYCLOGENESIS...AND THIS
SYSTEM WILL EVOLVE INTO DEEP LAYERED/CUT-OFF LOW PRESSURE. THIS
SYSTEM WILL DRIVE THE UPPER RIDGE WELL SOUTH OF THE REGION...BUT THE
IMPACTS ON SENSIBLE WEATHER REMAIN UNCERTAIN. IF THE ATLANTIC TROUGH
PHASES WITH THE UPPER LOW ALONG THE GULF COAST...AN UNSETTLED
PATTERN COULD DEVELOP OVER THE REGION. HOWEVER...IF THE SYSTEMS
REMAIN SEPARATE...SOMEWHAT DRIER AIR COULD SPREAD INTO THE REGION
FROM THE NORTH/NORTHWEST. THUS...POPS REMAIN PRETTY CLOSE TO
NORMAL. TEMPERATURES SHOULD REMAIN CLOSE TO NORMAL THROUGH THE
PERIOD...AND FORECAST TEMPERATURES REMAIN BELOW 90F THROUGH NEXT
WEEKEND. HOWEVER...THE PROBABILITY FOR WARMER TEMPS INTO THE LOWER
90S COULD INCREASE LATE WEEK INTO NEXT WEEKEND ESPECIALLY IF DRIER
AIR CIRCULATES INTO THE REGION.
&&
.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
THE OVERALL PICTURE IS A SWING TO GRADUALLY DETERIORATING
CONDITIONS WITH ARRIVAL OF SHOWERS AND STORMS BEFORE DAWN AT
BOTH KSAV AND KCHS. SHOWERS AND A FEW STORMS NUMEROUS THROUGH THE
AFTERNOON HOURS AS DEEP MOISTURE AND DYNAMIC LIFTING PROCESSES
RESULTING IN WIDESPREAD COVERAGE. PERIODS OF IFR CONDITIONS ARE
POSSIBLE DURING BOUTS OF HEAVIER RAINS AND/OR TSTMS TODAY...
ESPECIALLY FROM AROUND MIDDAY TO EARLY EVENING.
EXTENDED AVIATION OUTLOOK THROUGH THURSDAY...PERIODS OF FLIGHT
RESTRICTIONS APPEAR LIKELY THROUGH EARLY WEEK...ESPECIALLY IN
SHOWERS/THUNDERSTORMS. VFR SHOULD BECOME MORE COMMON MID TO LATE
WEEK.
&&
.MARINE...
ONSHORE FLOW WILL INCREASE ACROSS GEORGIA WATERS LATER TODAY AND
TONIGHT...PERHAPS 15-20 KT WITH SOME HIGHER GUSTS POSSIBLE FROM
GRAYS REEF AND BEYOND. THIS COULD ASSIST SEAS BUILDING TO SMALL
CRAFT ADVISORY LEVELS OVER GEORGIA WATERS FROM 20-60 NM LATER
TONIGHT. WIDESPREAD RAINS AND OCCASIONAL TSTMS OVER THE WATERS
THROUGH TONIGHT WILL LOWER VSBYS BELOW 3 NM AT TIMES AND PRODUCE
LOCALLY GUSTY WINDS...ESPECIALLY TONIGHT. WE HAVE HELD OFF ON
ISSUING AN SCA FOR OUTER WATERS JUST YET UNTIL WE GET A BETTER
HANDLE ON CONVECTION PATTERNS WHICH MAY DISRUPT WINDS BUT
LOCALLY ENHANCE WAVES.
PERSISTENT SE WINDS COULD USHER A 6 FT SWELL INTO GA COASTAL WATERS
BEYOND 20-40 NM MONDAY. THIS SCENARIO REMAINS UNCERTAIN...THUS WILL
NOT YET RAISE A SMALL CRAFT ADVISORY. OTHERWISE...SOUTHEAST WINDS
SHOULD REMAIN CAPPED AT 15-20 KT AND SEAS SHOULD REMAIN 3-5 FT
THROUGH TUESDAY. MID TO LATE WEEK...A WEAKENING ONSHORE PRESSURE
GRADIENT WILL TRANSLATE TO LIGHTER WINDS...FREQUENTLY 10 KT OR
LESS...AND SEAS SHOULD SUBSIDE TO 1-3 FT...HIGHEST BEYOND 20 NM.
MEANWHILE...SHOWERS/THUNDERSTORMS WILL REMAIN COMMON OVER COASTAL
WATERS THROUGH THIS WEEK. STRONGER THUNDERSTORMS COULD PRODUCE GUSTY
WINDS...FREQUENT LIGHTNING AND POOR VISIBILITY IN VERY HEAVY
RAINFALL. MARINERS SHOULD REMAIN ALERT FOR SPECIAL MARINE WARNINGS
AND MARINE WEATHER STATEMENTS.
MARINERS ARE ADVISED THAT SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS WILL OCCUR EACH OF THE NEXT SEVERAL DAYS AND NIGHTS.
SOME OF THESE STORMS WILL PRODUCE FREQUENT LIGHTNING...HEAVY RAINS
REDUCING VISIBILITIES TO NEAR ZERO AT TIMES AND WIND GUSTS UP TO
AT LEAST 30 KT WITH BRIEFLY HIGHER SEAS. REMEMBER TO MONITOR OUR
FORECASTS AND YOUR NOAA WEATHER RADIO.
CONDITIONS WON/T BE MUCH DIFFERENT SUNDAY WITH ONSHORE
WINDS...SMALL SWELLS AND ASTRONOMICAL INFLUENCES FROM THE PERIGEE
AND FULL MOON. THIS WILL RESULT IN AT LEAST A MODERATE RISK OF RIP
CURRENTS AT AREA BEACHES.
WHILE WE START TO LOSE THE ASTRONOMICAL INFLUENCES AS WE GO THROUGH
THE WEEK...THERE IS STILL AN ONSHORE WIND COMPONENT AND POSSIBLE
SMALL SWELLS TO GENERATE A POSSIBLE ELEVATED RISK DURING AT LEAST THE
EARLY PART OF THE WEEK.
RIP CURRENTS...A MODERATE RISK OF RIP CURRENTS MAY BE UPGRADED TO
HIGH RISK AT TYBEE ISLAND LATER THIS MORNING...OTHERWISE AN
ELEVATED RISK FOR RIP CURRENTS COULD PERSIST INTO EARLY THIS WEEK.
&&
.TIDES/COASTAL FLOODING...
THROUGH TONIGHT...ASTRONOMICAL INFLUENCES DUE TO THE PERIGEAN
SPRING TIDE PLUS ONSHORE WINDS WILL MAINTAIN ELEVATED HIGH TIDE
LEVELS ALONG THE COAST. WHILE WE WILL BE CLOSE TO POSSIBLE
SHALLOW COASTAL FLOODING IN CHARLESTON HARBOR WITH THE MORNING
HIGH TIDE TODAY...A BETTER CHANCE FOR SHALLOW SALT WATER FLOODING
EXISTS WITH THE EVENING HIGH TIDE. COASTAL FLOOD ADVISORIES WILL
LIKELY BE REQUIRED FOR AT LEAST PARTS OF THE SC COAST...AND WE/LL
BE CLOSE TO THE ADVISORY CRITERIA FURTHER SOUTH...INCLUDING THE
SAVANNAH AREA. ALSO OF NOTE...PERIODS OF SHOWERS/THUNDERSTORMS
WITH HEAVY RAIN ARE EXPECTED. IF HEAVY RAIN FALLS IN COASTAL
COMMUNITIES...INCLUDING DOWNTOWN CHARLESTON AND/OR DOWNTOWN
SAVANNAH AROUND THE TIMES OF HIGH TIDE...MORE SIGNIFICANT FLOODING
IS POSSIBLE.
MONDAY AND TUESDAY...LINGERING ASTRONOMICAL INFLUENCES AND
PERSISTENT ONSHORE FLOW COULD PRODUCE A COUPLE OF ADDITIONAL CYCLES
OF SHALLOW SALT WATER FLOODING WITH THE NIGHTTIME HIGH
TIDE...ESPECIALLY ALONG THE SOUTH CAROLINA COAST. ALSO OF CONCERN...
PERIODS OF HEAVY RAIN ARE POSSIBLE ALONG THE COAST EARLY THIS
WEEK...AND LOCALIZED FLOODING IS POSSIBLE ESPECIALLY IF HEAVY RAIN
FALLS AROUND THE TIMES OF HIGH TIDE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...SPR
LONG TERM...SPR
AVIATION...
MARINE...SPR
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
110 AM EDT SUN AUG 30 2015
.PREV DISCUSSION... /ISSUED 901 PM EDT SAT AUG 29 2015/
UPDATE...
UPDATED FORECAST IN GOOD SHAPE. SHRA STILL ACTIVE IN NW
CORNER...MIDDLE GA EAST OF KCSG AND FAR SE. LITTLE IF ANY
CONVECTION SEEN THIS AFTERNOON AND NONE EXPECTED OVERNIGHT.
ANOTHER ROUND OF SHRA LIKELY EARLY SUN MORNING BASED ON HRRR AND
SOME HIRES MODELS. NOT A SLAM DUNK BUT ENOUGH TO KEEP POPS FAIRLY
HIGH FOR THAT TIME OF NIGHT.
SNELSON
PREV DISCUSSION... /ISSUED 333 PM EDT SAT AUG 29 2015/
SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
THE SHORT TERM MODELS ARE IN GOOD AGREEMENT THROUGH THE PERIOD
KEEPING A MOIST AIRMASS IN PLACE. THE UPPER LEVEL LOW OVER THE
NORTHERN GULF WILL CONTINUE TO LIFT ACROSS SOUTH ALABAMA INTO
NORTHWEST GA BY SUNDAY EVENING AND NORTH OF THE FORECAST AREA
SUNDAY NIGHT. WEAK IMPULSES WILL CONTINUE TO LIFT ACROSS THE
FORECAST AREA AHEAD OF THE LOW. HIGH PRESSURE OVER THE CAROLINAS
WILL KEEP EASTERLY FLOW AT THE SURFACE. THIS WILL REINFORCE SOME
LOWER CLOUDS BY MORNING ACROSS THE AREA WITH MID LEVEL CEILINGS
EXPECTED ACROSS THE REGION. ALTHOUGH INSTABILITY WILL BE
MINIMAL...ISOLATED THUNDER WILL BE POSSIBLE AS THE IMPULSES LIFT
NORTH THROUGH TOMORROW. THE AREAS OF SHOWERS WILL CONTINUE
OVERNIGHT...WITH BEST CHANCES OVER WEST GA...BUT DO EXPECT SOME
LULLS. GUIDANCE TEMPERATURES ARE IN LINE AND HAVE TAKEN A BLEND OF
MAV/MET.
ATWELL
LONG TERM /MONDAY THROUGH SATURDAY/...
NO MAJOR CHANGES TO THE ONGOING LONG TERM FORECAST.
THE REMNANTS OF ERIKA STILL EXPECTED TO IMPACT THE CWFA NEXT WEEK.
FOR NOW...THE SYSTEM WILL REMAIN A LOW PRESSURE TROUGH AS IT COMES
ONSHORE ACROSS THE FLORIDA PANHANDLE EARLY NEXT WEEK.
THE PERSISTENT SOUTHERLY FLOW ALOFT WILL BRING ABUNDANT MOISTURE
NORTHWARD FROM THE GULF OF MEXICO FOR MUCH OF NEXT WEEK...SO CHANCE
POPS STILL NEEDED EVERY DAY. IN ADDITION...AN UPPER TROUGH ACROSS
THE EASTERN HALF OF THE COUNTRY WILL HELP KEEP TEMPERATURES MOSTLY
IN THE 80S THROUGH THE PERIOD.
WIND SHEAR IN THE GULF IS A LITTLE WEAKER...SO SOME REGENERATION OF
ERIKA IS POSSIBLE.
NLISTEMAA
&&
.AVIATION...
06Z UPDATE...
MAIN CONCERN IS POTENTIAL FOR ANY IFR/MVFR CEILINGS...PRECIP
TIMING...AND CHANCES FOR AFTERNOON THUNDERSTORMS. LOW CONFIDENCE
FORECAST FOR MOST ELEMENTS AND CONDITIONS WILL JUST HAVE TO BE
CLOSELY MONITORED FOR TRENDS. SURFACE WINDS ESE 10 KTS OR LESS.
//ATL CONFIDENCE...06Z UPDATE...
LOW CONFIDENCE ON PRECIP TIMING...CEILINGS...VSBYS...IMPACTS FROM
ANY AFTERNOON THUNDERSTORMS.
HIGH CONFIDENCE ON WINDS.
BDL
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 81 67 85 69 / 50 20 30 20
ATLANTA 82 69 85 70 / 50 20 20 10
BLAIRSVILLE 76 62 82 63 / 40 20 30 20
CARTERSVILLE 81 66 87 68 / 40 20 20 10
COLUMBUS 87 69 89 72 / 50 20 20 10
GAINESVILLE 78 67 83 69 / 50 20 30 20
MACON 84 69 87 70 / 50 30 30 20
ROME 82 66 87 68 / 40 20 20 10
PEACHTREE CITY 83 68 86 69 / 50 20 20 10
VIDALIA 86 70 85 72 / 50 40 50 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BDL
LONG TERM....DEESE
AVIATION...BDL
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1002 PM CDT MON AUG 31 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 03Z...
* POTENTIAL FOR FOG DEVELOPMENT OVERNIGHT.
BMD
//DISCUSSION...UPDATED 00Z...
LAKE BREEZE MADE SOME PROGRESS INLAND EARLIER THIS AFTERNOON AND
HAS SINCE RETREATED SLIGHTLY AND STALLED...INCLUDING RIGHT OVER
THE EASTERN PORTION OF ORD AIRFIELD...AND PROBABLY ABOUT A QUARTER
TO HALF A MILE EAST OF MDW. THIS HAS RESULTED IN SOUTHWESTERLY
FLOW HOLDING ON AT THE TERMINALS MUCH LONGER THAN EXPECTED AND
WITH LITTLE MOVEMENT OF THE BOUNDARY AND SUNSET SOON...NO LONGER
CONFIDENT IN SEEING A STRONG PUSH WITH A NOTABLE WINDSHIFT TO THE
NORTHEAST. MORE LIKELY WINDS MIGHT BACK SLIGHTLY TO THE SOUTHEAST
OR SOUTH-SOUTHEAST FOR A FEW HOURS THIS EVENING AS THE BOUNDARY
WASHES OUT...THEN WINDS SHOULD GRADUALLY VEER BACK TO THE SOUTH-
SOUTHWEST OVERNIGHT. WHATEVER THE WIND DIRECTION IS...WIND SPEEDS
WILL STAY BELOW 10 KT...AND LIKELY STAY 5-6 KT OR LESS. FOG WILL
ONCE AGAIN BE A CONCERN OVERNIGHT THOUGH SHOULDNT BE NEARLY AS BAD
AS MONDAY MORNING GIVEN THAT WE HAVE HAD A DRY DAY WITH DECENT
MIXING. SOUTHWEST WINDS APPEAR TO BE JUST STRONG ENOUGH TOMORROW
TO HOLD OFF A LAKE BREEZE PUSHING INLAND.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* LOW CONFIDENCE IN VSBY TRENDS OVERNIGHT.
* MEDIUM-HIGH CONFIDENCE IN WINDS.
BMD
//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.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
835 PM CDT MON AUG 31 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 00Z...
* POTENTIAL FOR FOG DEVELOPMENT OVERNIGHT.
BMD
//DISCUSSION...UPDATED 00Z...
LAKE BREEZE MADE SOME PROGRESS INLAND EARLIER THIS AFTERNOON AND
HAS SINCE RETREATED SLIGHTLY AND STALLED...INCLUDING RIGHT OVER
THE EASTERN PORTION OF ORD AIRFIELD...AND PROBABLY ABOUT A QUARTER
TO HALF A MILE EAST OF MDW. THIS HAS RESULTED IN SOUTHWESTERLY
FLOW HOLDING ON AT THE TERMINALS MUCH LONGER THAN EXPECTED AND
WITH LITTLE MOVEMENT OF THE BOUNDARY AND SUNSET SOON...NO LONGER
CONFIDENT IN SEEING A STRONG PUSH WITH A NOTABLE WINDSHIFT TO THE
NORTHEAST. MORE LIKELY WINDS MIGHT BACK SLIGHTLY TO THE SOUTHEAST
OR SOUTH-SOUTHEAST FOR A FEW HOURS THIS EVENING AS THE BOUNDARY
WASHES OUT...THEN WINDS SHOULD GRADUALLY VEER BACK TO THE SOUTH-
SOUTHWEST OVERNIGHT. WHATEVER THE WIND DIRECTION IS...WIND SPEEDS
WILL STAY BELOW 10 KT...AND LIKELY STAY 5-6 KT OR LESS. FOG WILL
ONCE AGAIN BE A CONCERN OVERNIGHT THOUGH SHOULDNT BE NEARLY AS BAD
AS MONDAY MORNING GIVEN THAT WE HAVE HAD A DRY DAY WITH DECENT
MIXING. SOUTHWEST WINDS APPEAR TO BE JUST STRONG ENOUGH TOMORROW
TO HOLD OFF A LAKE BREEZE PUSHING INLAND.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* LOW CONFIDENCE IN VSBY TRENDS OVERNIGHT.
* MEDIUM CONFIDENCE IN WIND DIRECTION THIS EVENING...MEDIUM-HIGH
FOR TOMORROW.
BMD
//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...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1232 PM CDT SUN AUG 30 2015
.UPDATE...
ISSUED AT 1050 AM CDT SUN AUG 30 2015
FOG FINALLY STARTING TO LIFT AND BREAK UP NW OF THE STALLED
FRONTAL BOUNDARY DRAPED ACROSS CENTRAL ILLINOIS THIS MORNING.
SOUTHERLY WINDS SOUTH OF THE BOUNDARY WILL RESULT IN SOME DRIFT
NORTHWARD..WITH PLENTY OF LLVL MOISTURE IN PLACE TO FILL IN THE
SKY WITH A BKN CU FIELD SHORTLY AFTER ANY CLEARING TAKES PLACE
THIS AFTERNOON. SAME CU COULD DEVELOP SOME VERTICAL EXTENT AND
TURN INTO SCT SHOWERS AND THUNDERSTORMS, PARTICULARLY SOUTH AND
EAST OF THE BOUNDARY. NO UPDATES ANTICIPATED AT THIS TIME, JUST
MINOR ADJUSTMENTS TO HOURLY TEMP TRENDS UNDER THE STRATUS/REMAINING
FOG IN THE NW.
&&
.SHORT TERM...(TODAY)
ISSUED AT 324 AM CDT SUN AUG 30 2015
08Z/3AM SURFACE ANALYSIS SHOWS A STATIONARY FRONTAL BOUNDARY
EXTENDING FROM JUST SOUTH OF CHICAGO TO NEAR KIRKSVILLE, MISSOURI.
WHILE CURRENT KILX RADAR IMAGERY INDICATES DRY CONDITIONS ACROSS THE
BOARD...A FEW SHOWERS ARE NOTED FURTHER SOUTHWEST FROM THE OZARKS
INTO THE OHIO RIVER VALLEY. MEANWHILE...LIGHT/VARIABLE WINDS AND
INCREASED LOW-LEVEL MOISTURE NEAR THE BOUNDARY HAVE LED TO THE
DEVELOPMENT OF FOG MAINLY ALONG/NORTHWEST OF A PITTSFIELD TO
BLOOMINGTON-NORMAL LINE. HRRR CONTINUES TO FOCUS MUCH OF THE
WIDESPREAD FOG ACROSS THIS AREA THROUGH MID-MORNING...SO WILL NEED
TO MONITOR VISBY TRENDS FOR A POSSIBLE DENSE FOG ADVISORY. FURTHER
EAST AND SOUTH ACROSS THE REMAINDER OF THE CWA...WILL ONLY MENTION
PATCHY FOG EARLY THIS MORNING. AFTER THE MORNING FOG
DISSIPATES...WIDELY SCATTERED SHOWERS/THUNDER WILL DEVELOP AHEAD OF
THE DECAYING FRONTAL BOUNDARY...PRIMARILY EAST OF THE ILLINOIS
RIVER. AFTERNOON HIGH TEMPERATURES WILL BE SIMILAR TO
YESTERDAY...PERHAPS A DEGREE OR TWO WARMER IN THE MIDDLE 80S.
.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 324 AM CDT SUN AUG 30 2015
THE EXTENDED LOOKS WARM AND DRY AS UPPER-LEVEL RIDGING DOMINATES THE
EASTERN CONUS THROUGH THE END OF THE WEEK. A SLIGHT WEAKNESS IN THE
RIDGE APPEARS TO DEVELOP ACROSS ILLINOIS INTO THE OHIO RIVER
VALLEY...POTENTIALLY TRIGGERING ISOLATED AFTERNOON/EVENING
CONVECTION TUESDAY THROUGH FRIDAY. HOWEVER...MID-LEVEL WARMING
BENEATH THE RIDGE WILL LIKELY LEAD TO CAPPING AND AN OVERALL
SUPPRESSION OF CONVECTION. AS A RESULT...WILL MAINTAIN A DRY
FORECAST WITH HIGH TEMPERATURES CLIMBING INTO THE UPPER 80S AND
LOWER 90S EACH DAY. THE NEXT SIGNIFICANT CHANCE FOR PRECIPITATION
WILL LIKELY HOLD OFF UNTIL EARLY NEXT WEEK WHEN A SHORT-WAVE TROUGH
GRADUALLY FLATTENS THE PREVAILING RIDGE AND PUSHES A COLD FRONT INTO
THE REGION. MODELS ARE NOT IN AGREEMENT CONCERNING TIMING THIS FAR
OUT...BUT TYPICAL TREND IN THIS TYPE OF SCENARIO IS USUALLY SLOWER.
AS A RESULT...WILL MAINTAIN DRY WEATHER THROUGH SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1227 PM CDT SUN AUG 30 2015
PIA IMPROVING SLOWLY AS THE FOG FROM THIS MORNING CONTINUES TO
LIFT OUT AND BURN OFF. BMI FINALLY COMING UP TO MVFR. TEMPOS FOR
MVFR AT LEAST FOR A COUPLE HOURS NW OF THE BOUNDARY, VFR THROUGH
THE EVENING/POST SUNSET. AROUND MIDNIGHT, EXPECT THE REDEVELOPMENT
OF THE FOG. HAVE STARTED THAT TREND WITHOUT DROPPING THE VIS TOO
MUCH. AREAS MAY SEE IFR TOWARDS DAWN. LIGHT AND VARIABLE
WINDS...WITH A SOUTHERLY FETCH MORE LIKELY SOUTH OF THE DECAYING
BOUNDARY.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HJS
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...HJS
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1055 AM CDT SUN AUG 30 2015
.UPDATE...
ISSUED AT 1050 AM CDT SUN AUG 30 2015
FOG FINALLY STARTING TO LIFT AND BREAK UP NW OF THE STALLED
FRONTAL BOUNDARY DRAPED ACROSS CENTRAL ILLINOIS THIS MORNING.
SOUTHERLY WINDS SOUTH OF THE BOUNDARY WILL RESULT IN SOME DRIFT
NORTHWARD..WITH PLENTY OF LLVL MOISTURE IN PLACE TO FILL IN THE
SKY WITH A BKN CU FIELD SHORTLY AFTER ANY CLEARING TAKES PLACE
THIS AFTERNOON. SAME CU COULD DEVELOP SOME VERTICAL EXTENT AND
TURN INTO SCT SHOWERS AND THUNDERSTORMS, PARTICULARLY SOUTH AND
EAST OF THE BOUNDARY. NO UPDATES ANTICIPATED AT THIS TIME, JUST
MINOR ADJUSTMENTS TO HOURLY TEMP TRENDS UNDER THE STRATUS/REMAINING
FOG IN THE NW.
&&
.SHORT TERM...(TODAY)
ISSUED AT 324 AM CDT SUN AUG 30 2015
08Z/3AM SURFACE ANALYSIS SHOWS A STATIONARY FRONTAL BOUNDARY
EXTENDING FROM JUST SOUTH OF CHICAGO TO NEAR KIRKSVILLE, MISSOURI.
WHILE CURRENT KILX RADAR IMAGERY INDICATES DRY CONDITIONS ACROSS THE
BOARD...A FEW SHOWERS ARE NOTED FURTHER SOUTHWEST FROM THE OZARKS
INTO THE OHIO RIVER VALLEY. MEANWHILE...LIGHT/VARIABLE WINDS AND
INCREASED LOW-LEVEL MOISTURE NEAR THE BOUNDARY HAVE LED TO THE
DEVELOPMENT OF FOG MAINLY ALONG/NORTHWEST OF A PITTSFIELD TO
BLOOMINGTON-NORMAL LINE. HRRR CONTINUES TO FOCUS MUCH OF THE
WIDESPREAD FOG ACROSS THIS AREA THROUGH MID-MORNING...SO WILL NEED
TO MONITOR VISBY TRENDS FOR A POSSIBLE DENSE FOG ADVISORY. FURTHER
EAST AND SOUTH ACROSS THE REMAINDER OF THE CWA...WILL ONLY MENTION
PATCHY FOG EARLY THIS MORNING. AFTER THE MORNING FOG
DISSIPATES...WIDELY SCATTERED SHOWERS/THUNDER WILL DEVELOP AHEAD OF
THE DECAYING FRONTAL BOUNDARY...PRIMARILY EAST OF THE ILLINOIS
RIVER. AFTERNOON HIGH TEMPERATURES WILL BE SIMILAR TO
YESTERDAY...PERHAPS A DEGREE OR TWO WARMER IN THE MIDDLE 80S.
.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 324 AM CDT SUN AUG 30 2015
THE EXTENDED LOOKS WARM AND DRY AS UPPER-LEVEL RIDGING DOMINATES THE
EASTERN CONUS THROUGH THE END OF THE WEEK. A SLIGHT WEAKNESS IN THE
RIDGE APPEARS TO DEVELOP ACROSS ILLINOIS INTO THE OHIO RIVER
VALLEY...POTENTIALLY TRIGGERING ISOLATED AFTERNOON/EVENING
CONVECTION TUESDAY THROUGH FRIDAY. HOWEVER...MID-LEVEL WARMING
BENEATH THE RIDGE WILL LIKELY LEAD TO CAPPING AND AN OVERALL
SUPPRESSION OF CONVECTION. AS A RESULT...WILL MAINTAIN A DRY
FORECAST WITH HIGH TEMPERATURES CLIMBING INTO THE UPPER 80S AND
LOWER 90S EACH DAY. THE NEXT SIGNIFICANT CHANCE FOR PRECIPITATION
WILL LIKELY HOLD OFF UNTIL EARLY NEXT WEEK WHEN A SHORT-WAVE TROUGH
GRADUALLY FLATTENS THE PREVAILING RIDGE AND PUSHES A COLD FRONT INTO
THE REGION. MODELS ARE NOT IN AGREEMENT CONCERNING TIMING THIS FAR
OUT...BUT TYPICAL TREND IN THIS TYPE OF SCENARIO IS USUALLY SLOWER.
AS A RESULT...WILL MAINTAIN DRY WEATHER THROUGH SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 650 AM CDT SUN AUG 30 2015
PATCHY DENSE FOG POSSIBLE TO START THE DAY ACROSS THE CENTRAL
ILLINOIS TERMINAL AREA. THE FOG SHOULD BE BURNING OFF OVER THE
NEXT COUPLE OF HOURS, LEAVING VFR CONDITIONS FOR THE BULK OF THE
12Z TAF VALID TIME. HOWEVER, FOG MAY REDEVELOP LATER TONIGHT.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HJS
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...BAK
AREA FORECAST DISCUSSION
NWS LINCOLN IL
653 AM CDT SUN AUG 30 2015
.SHORT TERM...(TODAY)
ISSUED AT 324 AM CDT SUN AUG 30 2015
08Z/3AM SURFACE ANALYSIS SHOWS A STATIONARY FRONTAL BOUNDARY
EXTENDING FROM JUST SOUTH OF CHICAGO TO NEAR KIRKSVILLE, MISSOURI.
WHILE CURRENT KILX RADAR IMAGERY INDICATES DRY CONDITIONS ACROSS THE
BOARD...A FEW SHOWERS ARE NOTED FURTHER SOUTHWEST FROM THE OZARKS
INTO THE OHIO RIVER VALLEY. MEANWHILE...LIGHT/VARIABLE WINDS AND
INCREASED LOW-LEVEL MOISTURE NEAR THE BOUNDARY HAVE LED TO THE
DEVELOPMENT OF FOG MAINLY ALONG/NORTHWEST OF A PITTSFIELD TO
BLOOMINGTON-NORMAL LINE. HRRR CONTINUES TO FOCUS MUCH OF THE
WIDESPREAD FOG ACROSS THIS AREA THROUGH MID-MORNING...SO WILL NEED
TO MONITOR VISBY TRENDS FOR A POSSIBLE DENSE FOG ADVISORY. FURTHER
EAST AND SOUTH ACROSS THE REMAINDER OF THE CWA...WILL ONLY MENTION
PATCHY FOG EARLY THIS MORNING. AFTER THE MORNING FOG
DISSIPATES...WIDELY SCATTERED SHOWERS/THUNDER WILL DEVELOP AHEAD OF
THE DECAYING FRONTAL BOUNDARY...PRIMARILY EAST OF THE ILLINOIS
RIVER. AFTERNOON HIGH TEMPERATURES WILL BE SIMILAR TO
YESTERDAY...PERHAPS A DEGREE OR TWO WARMER IN THE MIDDLE 80S.
.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 324 AM CDT SUN AUG 30 2015
THE EXTENDED LOOKS WARM AND DRY AS UPPER-LEVEL RIDGING DOMINATES THE
EASTERN CONUS THROUGH THE END OF THE WEEK. A SLIGHT WEAKNESS IN THE
RIDGE APPEARS TO DEVELOP ACROSS ILLINOIS INTO THE OHIO RIVER
VALLEY...POTENTIALLY TRIGGERING ISOLATED AFTERNOON/EVENING
CONVECTION TUESDAY THROUGH FRIDAY. HOWEVER...MID-LEVEL WARMING
BENEATH THE RIDGE WILL LIKELY LEAD TO CAPPING AND AN OVERALL
SUPPRESSION OF CONVECTION. AS A RESULT...WILL MAINTAIN A DRY
FORECAST WITH HIGH TEMPERATURES CLIMBING INTO THE UPPER 80S AND
LOWER 90S EACH DAY. THE NEXT SIGNIFICANT CHANCE FOR PRECIPITATION
WILL LIKELY HOLD OFF UNTIL EARLY NEXT WEEK WHEN A SHORT-WAVE TROUGH
GRADUALLY FLATTENS THE PREVAILING RIDGE AND PUSHES A COLD FRONT INTO
THE REGION. MODELS ARE NOT IN AGREEMENT CONCERNING TIMING THIS FAR
OUT...BUT TYPICAL TREND IN THIS TYPE OF SCENARIO IS USUALLY SLOWER.
AS A RESULT...WILL MAINTAIN DRY WEATHER THROUGH SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 650 AM CDT SUN AUG 30 2015
PATCHY DENSE FOG POSSIBLE TO START THE DAY ACROSS THE CENTRAL
ILLINOIS TERMINAL AREA. THE FOG SHOULD BE BURNING OFF OVER THE
NEXT COUPLE OF HOURS, LEAVING VFR CONDITIONS FOR THE BULK OF THE
12Z TAF VALID TIME. HOWEVER, FOG MAY REDEVELOP LATER TONIGHT.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...BAK
AREA FORECAST DISCUSSION
NWS LINCOLN IL
324 AM CDT SUN AUG 30 2015
.SHORT TERM...(TODAY)
ISSUED AT 324 AM CDT SUN AUG 30 2015
08Z/3AM SURFACE ANALYSIS SHOWS A STATIONARY FRONTAL BOUNDARY
EXTENDING FROM JUST SOUTH OF CHICAGO TO NEAR KIRKSVILLE, MISSOURI.
WHILE CURRENT KILX RADAR IMAGERY INDICATES DRY CONDITIONS ACROSS THE
BOARD...A FEW SHOWERS ARE NOTED FURTHER SOUTHWEST FROM THE OZARKS
INTO THE OHIO RIVER VALLEY. MEANWHILE...LIGHT/VARIABLE WINDS AND
INCREASED LOW-LEVEL MOISTURE NEAR THE BOUNDARY HAVE LED TO THE
DEVELOPMENT OF FOG MAINLY ALONG/NORTHWEST OF A PITTSFIELD TO
BLOOMINGTON-NORMAL LINE. HRRR CONTINUES TO FOCUS MUCH OF THE
WIDESPREAD FOG ACROSS THIS AREA THROUGH MID-MORNING...SO WILL NEED
TO MONITOR VISBY TRENDS FOR A POSSIBLE DENSE FOG ADVISORY. FURTHER
EAST AND SOUTH ACROSS THE REMAINDER OF THE CWA...WILL ONLY MENTION
PATCHY FOG EARLY THIS MORNING. AFTER THE MORNING FOG
DISSIPATES...WIDELY SCATTERED SHOWERS/THUNDER WILL DEVELOP AHEAD OF
THE DECAYING FRONTAL BOUNDARY...PRIMARILY EAST OF THE ILLINOIS
RIVER. AFTERNOON HIGH TEMPERATURES WILL BE SIMILAR TO
YESTERDAY...PERHAPS A DEGREE OR TWO WARMER IN THE MIDDLE 80S.
&&
.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 324 AM CDT SUN AUG 30 2015
THE EXTENDED LOOKS WARM AND DRY AS UPPER-LEVEL RIDGING DOMINATES THE
EASTERN CONUS THROUGH THE END OF THE WEEK. A SLIGHT WEAKNESS IN THE
RIDGE APPEARS TO DEVELOP ACROSS ILLINOIS INTO THE OHIO RIVER
VALLEY...POTENTIALLY TRIGGERING ISOLATED AFTERNOON/EVENING
CONVECTION TUESDAY THROUGH FRIDAY. HOWEVER...MID-LEVEL WARMING
BENEATH THE RIDGE WILL LIKELY LEAD TO CAPPING AND AN OVERALL
SUPPRESSION OF CONVECTION. AS A RESULT...WILL MAINTAIN A DRY
FORECAST WITH HIGH TEMPERATURES CLIMBING INTO THE UPPER 80S AND
LOWER 90S EACH DAY. THE NEXT SIGNIFICANT CHANCE FOR PRECIPITATION
WILL LIKELY HOLD OFF UNTIL EARLY NEXT WEEK WHEN A SHORT-WAVE TROUGH
GRADUALLY FLATTENS THE PREVAILING RIDGE AND PUSHES A COLD FRONT INTO
THE REGION. MODELS ARE NOT IN AGREEMENT CONCERNING TIMING THIS FAR
OUT...BUT TYPICAL TREND IN THIS TYPE OF SCENARIO IS USUALLY SLOWER.
AS A RESULT...WILL MAINTAIN DRY WEATHER THROUGH SUNDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1154 PM CDT SAT AUG 29 2015
FOG FORMATION AND LOW CLOUDS ARE THE PRIMARY CONCERNS OVER THE
FIRST 6-9 HOURS OF THE TAF PERIOD. THE WEAKENING COLD FRONT HAS
BASICALLY STALLED OUT FROM NE TO SW ROUGHLY ALONG I-55 AS A
STATIONARY FRONT. AS A RESULT OF THE WEAK PRESSURE GRADIENT IN THE
VICINITY OF THE FRONT, THE WINDS WILL REMAIN LIGHT AND VARIABLE
OVERNIGHT. THAT WILL LEAD TO THE POTENTIAL FOR AREAS OF DENSE FOG
TO FORM, ESPECIALLY N-NW OF THE FRONT AROUND PIA AND BMI. FOG FOR
THE OTHER TERMINAL SITES COULD REMAIN MVFR, BUT HRRR AND RAP
OUTPUT CONTINUE TO SHOW AREAS OF DENSE FOG FARTHER SOUTH FROM SPI
TO CMI, SO WILL MONITOR DENSE FOG CLOSELY FOR POSSIBLE SIGNIFICANT
VIS REDUCTION FOR THE OTHER TERMINALS.
TOMORROW MORNING WINDS ARE FORECAST TO RETURN TO THE SOUTH-
SOUTHWEST AND REMAINING LESS THAN 10 KT THROUGH THE DAY.
CLOUDS WILL POSSIBLE DIP TO LIFR AT PIA AND BMI (OR ANY SITE THAT
EXPERIENCES DENSE FOG), WITH MVFR CLOUDS AT THE OTHER TAF SITES
FOR A FEW HOURS AFTER SUNRISE. BY MID MORNING, LOW CLOUDS SHOULD
LIFT TO VFR LEVELS AS DIURNAL MIXING INCREASES AND RAISES THE LCL.
CLOUDS ARE FORECAST TO PERSIST UNTIL LATER AFTERNOON, AS A LOBE OF
THE UPPER TROUGH RETROGRADES INTO IL FROM THE E-SE. SHOWER CHANCES
WILL INCREASE EAST OF CMI AND DEC, BUT WE KEPT THE TAF DRY FOR
NOW.
SKIES SHOULD BEGIN TO CLEAR OUT BY SUNDAY EVENING, WITH LIGHT
SOUTH WINDS THROUGH 31/06Z.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...SHIMON
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1154 PM CDT SAT AUG 29 2015
.UPDATE...
ISSUED AT 900 PM CDT SAT AUG 29 2015
A LINGERING BAND OF SHOWERS WILL CONTINUE ACROSS CENTRAL AND
EASTERN ILLINOIS THIS EVENING, THEN BEGIN TO PROGRESS EAST AFTER
MIDNIGHT. THE UPPER LEVEL TROUGH AXIS EXTENDS ACROSS IL FROM NE TO
SW, AND WILL BE THE FOCUS FOR THE CONTINUED CHANCES OF PRECIP
OVERNIGHT. CLOUDS WILL PRIMARILY DOMINATE THE SKIES OVERNIGHT, BUT
PATCHES OF CLEARING ARE SHOWING UP IN EASTERN IOWA AND FAR WESTERN
IL ON THE LATEST SATELLITE IMAGES. ANY CLEARING NW OF THE IL RIVER
WILL LIKELY RESULT IN FOG FORMATION, WITH SOME AREAS SEEING DENSE
FOG. HAVE LEFT A MENTION OF FOG FOR NW OF THE IL RIVER, BUT THERE
IS SOME INDICATIONS IN THE HRRR AND RAP THAT THE FOG COULD AFFECT
SPOTTY AREAS IN THE REMAINDER OF OUR FORECAST AREA. FOR NOW, WILL
NOT INCLUDE FOG EVERYWHERE, BUT WILL WATCH CLOSELY FOR ANY
CLEARING IN THE CLOUDS EAST OF THE IL RIVER, WHICH WOULD INCREASE
FOG POTENTIAL THERE.
LOW TEMPS WILL BE MAINLY HELD IN THE MID 60S DUE TO CLOUD COVER
AND MINIMAL AIRMASS CHANGE OVERNIGHT UNDER LIGHT AND VARIABLE
WINDS. UPDATED THE WEATHER/POP/SKY GRIDS TO MATCH EXPECTED TRENDS.
THE REMAINDER OF THE FORECAST INFO APPEARS ON TRACK.
&&
.SHORT TERM...(TONIGHT)
ISSUED AT 228 PM CDT SAT AUG 29 2015
LATEST SURFACE MAP SHOWING FRONTAL BOUNDARY ARCING FROM THE
NORTHEAST TIP OF ILLINOIS TO EAST CENTRAL IOWA...BEFORE EXTENDING
SOUTHWEST INTO SOUTHEAST KANSAS. PRECIPITATION HAS LARGELY REMAINED
LIGHT AND SCATTERED...AND HAS BEEN MOSTLY EAST OF I-55 THE LAST
SEVERAL HOURS. DECENT SLUG OF DRY AIR ALOFT SEEN ON WATER VAPOR
IMAGERY SOUTH OF A SHORTWAVE...WHICH IS CURRENTLY DROPPING INTO
SOUTHERN IOWA. SHORT-RANGE MODEL GUIDANCE IS HAVING A BIT OF
DIFFICULTY AS TO THE AMOUNT OF REDEVELOPMENT...BUT THE HRRR IS
PERFORMING HALFWAY DECENTLY AND CONTINUES TO SUGGEST MAINLY SCATTERED
SHOWERS. THUNDER HAS BEEN STAYING AWAY FROM OUR AREA SO FAR...AND
WHILE MESOANALYSIS SHOWS RESPECTABLE CAPE VALUES OF 1000-1500 J/KG
THIS AFTERNOON...MID LEVEL LAPSE RATES ARE FAIRLY MODEST. THEREFORE
WILL CONTINUE MENTION WITH ONLY ISOLATED THUNDERSTORMS THROUGH
TONIGHT...WITH THE THREAT DIMINISHING FROM NORTHWEST TO SOUTHEAST.
SOME CONCERNS LATER IN THE NIGHT WITH POTENTIAL FOR SOME FOG...
MAINLY ACROSS THE NORTHWEST CWA. STILL QUITE A BIT OF LOWER
STRATOCUMULUS ACROSS MOST OF IOWA AND WISCONSIN. LATEST RAP MODEL
GUIDANCE SUGGESTS THIS CONTRACTING SOME MORE OVER THE NEXT SEVERAL
HOURS...BEFORE SIGNIFICANTLY EXPANDING AGAIN THIS EVENING WITH HIGH
PRESSURE EXPANDING OVER THE MIDWEST. MUCH OF THE AREA UNDERNEATH
THIS HIGH SAW FROM 1 TO SEVERAL INCHES OF RAIN IN THE LAST COUPLE
DAYS...AND IS MOST FAVORED FOR DENSE FOG POTENTIAL. HOWEVER...THE
RAP SHOWS THE FOG FIELD OOZING SOUTHWARD AFTER MIDNIGHT...PERHAPS AS
FAR AS PEORIA. THAT AREA ALREADY HAD PATCHY FOG IN THE GRIDS...BUT
AM THINKING IT WILL BE A BIT MORE WIDESPREAD AND WILL GO WITH AREAS
OF FOG INSTEAD.
.LONG TERM...(SUNDAY THROUGH SATURDAY)
ISSUED AT 228 PM CDT SAT AUG 29 2015
SHOWERS AND ISOLATED THUNDERSTORMS COULD LINGER IN THE SOUTHEASTERN
PART OF THE CWA SUNDAY MORNING BUT THEN SPREAD BACK WEST
SOME...COVERING THE EASTERN HALF OF THE CWA...MAINLY EAST OF I-55.
THIS SHOULD BE THE END OF THE PCPN AS THE FRONTAL SYSTEM DIMINISHES
OVER THE AREA REMAINDER OF THE WEEKEND. FOG AND LOWER CLOUDS WILL
SEEN THIS MORNING ALONG AND BEHIND THE FRONT...SO THINKING IS THAT
THE FOG WILL CONTINUE INTO THE FIRST FEW HOURS OF SUNDAY MORNING.
HAVE INCLUDED A SLIGHT CHANCE OF SHOWERS FOR SUNDAY NIGHT...AGAIN
MAINLY EAST OF I-55 TIL MIDNIGHT...AND THEN IN THE EXTREME SOUTHEAST
AFTER MIDNIGHT.
BEYOND THIS UPPER LEVEL RIDGING WILL BUILD INTO THE NORTHERN PLAINS
AND NORTHERN MISS VALLEY. ON THE SFC...HIGH PRESSURE RIDGING WILL
BUILD BACK TOWARD THE AREA FROM THE SOUTHEAST. THE COMBINATION OF
THE TWO SHOULD HELP TO KEEP THE AREA DRY THROUGH THE BEGINNING OF
THE WEEK. TEMPS WILL BE IN THE LOWER TO MIDDLE 80S TOMORROW...BUT
THEN WARM INTO THE MIDDLE TO UPPER 80S FOR MONDAY INTO TUESDAY.
THE REMAINDER OF THE WEEK LOOKS TO BE DRY...THOUGH SOME OF THE
MODELS CONTINUE TO BRING SOME SPOTTY POPS IN THE AREA DUE TO
SOUTHERLY FLOW ON THE SFC. FOR NOW...WILL ONLY HAVE SLIGHT CHC POPS
FOR WED ACROSS AREAS ALONG AND NORTH OF I-74 AND EAST OF I-57.
REMAINDER OF THE WEEK WITH BE DRY...EVEN INTO THE BEGINNING OF THE
LABOR DAY WEEKEND. TEMPS WILL REMAIN WELL ABOVE NORMAL IN THE
EXTENDED PERIOD SO HEAT COULD BE AN ISSUE LATER...BUT DEWPOINTS WILL
REMAIN LOW SO HEAT INDEX VALUES ARE NOT EXPECTED TO GET OVER 100
THROUGH THE PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1154 PM CDT SAT AUG 29 2015
FOG FORMATION AND LOW CLOUDS ARE THE PRIMARY CONCERNS OVER THE
FIRST 6-9 HOURS OF THE TAF PERIOD. THE WEAKENING COLD FRONT HAS
BASICALLY STALLED OUT FROM NE TO SW ROUGHLY ALONG I-55 AS A
STATIONARY FRONT. AS A RESULT OF THE WEAK PRESSURE GRADIENT IN THE
VICINITY OF THE FRONT, THE WINDS WILL REMAIN LIGHT AND VARIABLE
OVERNIGHT. THAT WILL LEAD TO THE POTENTIAL FOR AREAS OF DENSE FOG
TO FORM, ESPECIALLY N-NW OF THE FRONT AROUND PIA AND BMI. FOG FOR
THE OTHER TERMINAL SITES COULD REMAIN MVFR, BUT HRRR AND RAP
OUTPUT CONTINUE TO SHOW AREAS OF DENSE FOG FARTHER SOUTH FROM SPI
TO CMI, SO WILL MONITOR DENSE FOG CLOSELY FOR POSSIBLE SIGNIFICANT
VIS REDUCTION FOR THE OTHER TERMINALS.
TOMORROW MORNING WINDS ARE FORECAST TO RETURN TO THE SOUTH-
SOUTHWEST AND REMAINING LESS THAN 10 KT THROUGH THE DAY.
CLOUDS WILL POSSIBLE DIP TO LIFR AT PIA AND BMI (OR ANY SITE THAT
EXPERIENCES DENSE FOG), WITH MVFR CLOUDS AT THE OTHER TAF SITES
FOR A FEW HOURS AFTER SUNRISE. BY MID MORNING, LOW CLOUDS SHOULD
LIFT TO VFR LEVELS AS DIURNAL MIXING INCREASES AND RAISES THE LCL.
CLOUDS ARE FORECAST TO PERSIST UNTIL LATER AFTERNOON, AS A LOBE OF
THE UPPER TROUGH RETROGRADES INTO IL FROM THE E-SE. SHOWER CHANCES
WILL INCREASE EAST OF CMI AND DEC, BUT WE KEPT THE TAF DRY FOR
NOW.
SKIES SHOULD BEGIN TO CLEAR OUT BY SUNDAY EVENING, WITH LIGHT
SOUTH WINDS THROUGH 31/06Z.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SHIMON
SHORT TERM...GEELHART
LONG TERM...AUTEN
AVIATION...SHIMON
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
333 PM CDT SUN AUG 30 2015
.SYNOPSIS...
ISSUED AT 314 PM CDT SUN AUG 30 2015
SURFACE RIDGE AXIS EXTENDS FROM THE GREAT LAKES THROUGH THE CWA
AND INTO THE SOUTH CENTRAL PLAINS AT MID AFTN. THE FAIRLY
WIDESPREAD DENSE FOG BURNED OFF BY MID TO LATE AM LEAVING BEHIND
FAIRLY EXTENSIVE STRATUS WHICH HAS BEEN STEADILY ERODING FROM THE
SOUTH AND EVOLVING INTO SCATTERED STRATOCU DECK. THE INCREASING
PEAKS OF SUNSHINE HAS HELPED TO BUMP TEMPS UP TO NEAR LATE
AUGUST NORMALS WITH MANY AREAS IN THE UPPER 70S TO LOWER 80S.
THE EXCEPTION BEING MAINLY PORTIONS OF NORTHEAST IA WHERE STRATUS
SILL LINGERS AND AIDING IN HOLDING TEMPS DOWN IN THE LOWER 70S
ATTIM... BUT WITH MORE LATE DAY SUNSHINE SHOULD SEE TEMPS IN THESE
AREAS SURGE LATE. PATTERN ALOFT FEATURES AN AMPLIFIED RIDGE /HEAT DOME/
THROUGH THE PLAINS IN ADVANCE OF A PACIFIC NORTHWEST TROUGH. THE NEXT
24 HOURS WILL SEE THIS RIDGE AND WARMER AIR BUILD INTO THE MID-
MISSISSIPPI VLY AS THE PACIFIC NORTHWEST TROUGH SHIFTS ACROSS THE
NORTHERN ROCKIES. THIS WILL RESULT IN CONTINUATION OF DRY CONDITIONS
WITH WARMER TEMPS ON MONDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 314 PM CDT SUN AUG 30 2015
MAIN CHALLENGE REMAINS LOW CLOUDS AND FOG POTENTIAL WITH IMPACT ON
TEMPS.
FOLLOWING TRENDS PER SATL AND OBS FROM LATE AFTN WITH DECREASING STRATUS
NORTHWEST CWA EVOLVING INTO SCATTERED STRATOCUMULUS THEN MOSTLY
CLEAR FOR A TIME THIS EVENING. LATE EVENING AND OVERNIGHT WITH
CONTINUED WEAK WINDS AND ABUNDANT LOW LEVEL MOISTURE EXPECT
REDEVELOPMENT OF FOG DENSE IN SOME AREAS... WITH ALSO SOME STRATUS
POSSIBLE ALTHOUGH UNCERTAIN ON EXTENT OF ANY STRATUS FORMATION WITH
LATEST RAP AND NAM MODELS SHOWING AROUND 15+ KTS OF WIND JUST ABOVE
MOIST LAYER WHICH MAY BE SUFFICIENT MIXING TO OFFSET WIDESPREAD STRATUS
FORMATION AND WITH JUST DIURNAL CUMULUS ACROSS MO DON/T EXPECT ANY
ADVECTION OF LOW DECK. MIN TEMPS WILL BE CHALLENGING AND DEPENDENT ON
FOG AND STRATUS TRENDS. AS WE SAW THIS AM... POTENTIAL FOR AREAS THAT
STAY CLEAR LONGER TO RADIATE DOWN INTO THE 50S WITH NEAR CALM WINDS.
OTHERWISE... WITH TEMPS A BIT WARMER TODAY FOR MANY AND WITH MID AFTN
DEWPTS IN MID/UPPER 60S I HAVE KEPT LOWS MAINLY IN RANGE OF 60-67 DEGS.
ON MONDAY...ANY FOG SHOULD BURN OFF A BIT EARLIER TOMORROW BY MID AM
WITH A BIT STRONGER SOUTHERLY WIND DEVELOPING OF 5-10 KTS. ANY
STRATUS SHOULD LIFT TO FAIR WX CUMULUS DURING AFTERNOON AND GENERALLY
MOSTLY SUNNY SKIES. THIS WILL ALLOW TEMPS TO CLIMB WELL INTO THE 80S
WITH WIDESPREAD MID TO A FEW UPPER 80S. THESE TEMPS COUPLED WITH
DEWPTS WELL IN THE 60S TO NEAR 70 DEGS WILL MAKE FOR VERY WARM FEEL
WITH HEAT INDICES AROUND 90/L90S.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 314 PM CDT SUN AUG 30 2015
OVERVIEW...BUILDING AND PERSISTENT UPPER-LEVEL RIDGE OVER THE
CENTRAL U.S. WILL LEAD TO ABOVE AVERAGE TEMPERATURES AND HUMID
CONDITIONS THROUGH THE EXTENDED PERIOD. OVERALL CHANCES FOR RAIN
ARE VERY LOW.
TUESDAY AND WEDNESDAY...1000-500MB THICKNESS VALUES ARE FORECAST TO
BE NEAR 576-579 DAM WITH 850MB TEMPS IN THE UPPER TEENS/NEAR 20 C.
FORECAST HIGHS ARE IN THE UPPER 80S TO NEAR 90 F...WITH HEAT INDICES
IN THE LOWER TO MIDDLE 90S.
A SHORTWAVE TROUGH FROM REMNANT MONSOONAL CONVECTION MAY TRAVERSE
THE MIDWEST ON WEDNESDAY BUT MODELS TRACK IT NW OF E IOWA/W
ILLINOIS. CONSEQUENTLY KEPT THE FORECAST DRY.
THURSDAY THROUGH SATURDAY...RAW MODELS STILL APPEAR TO HAVE A WARM
BIAS AND ARE PROJECTING LOWER TO MIDDLE 90S. HUMID
CONDITIONS...850MB TEMPS IN THE UPPER TEENS TO POSSIBLY LOWER 20S
CELSIUS...AND A LOWER SEPTEMBER SUN ANGLE BACK A TEMP FORECAST
SLIGHTLY BELOW THE HIGHER RAW MODEL DATA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 116 PM CDT SUN AUG 30 2015
ANTICIPATE STRATUS TO CONTINUE LIFTING TO SCT-BKN STRATOCU DECK WITH
WIDESPREAD MVFR BASES AND CIGS BECOMING VFR BY LATE PM. GIVEN
CONTINUED WEAK LOW LEVEL FLOW AND ABUNDANT MOISTURE EXPECT MORE FOG
TO DEVELOP BY LATE EVENING AND OVERNIGHT WITH POTENTIAL FOR SOME STRATUS
WITH CONDITIONS LOWERING INTO MVFR TO IFR... WITH POCKETS OF LIFR/VLIFR.
ON MONDAY EXPECT SIMILAR TRENDS TO TODAY WITH FOG LIFTING BY AROUND
MID AM WITH ANY STRATUS LIFTING INTO VFR STRATOCU DECK DURING AFTERNOON.
LIGHT AND VARIABLE WINDS WILL TURN SOUTHERLY AT 5-10 KTS ON MONDAY.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...MCCLURE
SHORT TERM...MCCLURE
LONG TERM...UTTECH
AVIATION...MCCLURE
AREA FORECAST DISCUSSION
NWS JACKSON KY
133 AM EDT SUN AUG 30 2015
.UPDATE...
ISSUED AT 133 AM EDT SUN AUG 30 2015
UPDATED THE FORECAST TO INPUT THE LATEST OBSERVATIONS INTO THE
GRIDS FOR TEMPERATURES...DEW POINTS...AND WINDS. OTHERWISE NOT TOO
MANY CONCERNS WITH THIS UPDATE. ALL SHOWERS HAVE ENDED EARLIER AND
HAVE LEFT FOG IN THE FORECAST THROUGH DAWN.
UPDATE ISSUED AT 1036 PM EDT SAT AUG 29 2015
THE FORECAST THROUGH 12Z TOMORROW HAS BEEN UPDATED. REGIONAL RADAR
IMAGERY HAS SHOWN THAT SHOWER AND STORM ACTIVITY ACROSS CENTRAL
AND EASTERN KENTUCKY HAS ENDED OVER THE PAST COUPLE OF HOURS.
RAIN SHOWERS ACROSS TENNESSEE ARE ALSO CONTINUING TO RAPIDLY
DISSIPATE. CONSIDERING THE SUN HAS LONG SINCE STOPPED ADDING
ENERGY TO THE ATMOSPHERE...AND WITH NO NEW ACTIVITY FORMING
ANYWHERE IN OR NEAR OUR AREA...AND WITH ADDED SUPPORT FROM THE
LATEST MODEL DATA OF DRY WEATHER OVERNIGHT...THE DECISION WAS MADE
TO REMOVE PRECIPITATION FROM THE FORECAST THROUGH 12Z SUNDAY.
ISOLATED SHOWERS AND STORMS SHOULD START TO FIRE AGAIN TOMORROW
MORNING ONCE THE SUN HAS BEEN UP FOR AWHILE AND THE ATMOSPHERE
BECOMES REENERGIZED. THE HAZARDOUS WEATHER OUTLOOK HAS ALSO BEEN
UPDATED TO REFLECT NO HAZARDOUS WEATHER ACROSS THE AREA TONIGHT.
SOME VALLEY IS STILL EXPECTED TO FORM...BUT SHOULD NOT CAUSE ANY
ISSUES. THE NEW FORECAST AND HWO HAVE BOTH ALREADY BEEN ISSUED.
UPDATE ISSUED AT 732 PM EDT SAT AUG 29 2015
THE FORECAST IS ON TRACK SO FAR THIS EVENING. A FEW STRAY RAIN
SHOWERS AREA AFFECTING AREAS ALONG AND NORTH OF I64 AND DOWN IN
WAYNE COUNTY. THIS MATCHES WELL WITH THE SLIGHT CHANCE POPS
CURRENTLY IN THE LATEST HOURLY FORECAST GRIDS FOR BOTH THOSE
AREAS. THESE SHOWERS WILL DIMINISH STEADILY THIS EVENING AS THE
SUN GOES DOWN. THE LATEST HOURLY OBS AND BLENDED MODEL DATA HAVE
BEEN INGESTED INTO THE GRIDS TO ESTABLISH NEW TRENDS. ASIDE FROM
THAT THE FORECAST WAS UNCHANGED. THEREFORE...NO UPDATE IS
PLANNED AT THIS TIME.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 355 PM EDT SAT AUG 29 2015
19Z SFC ANALYSIS SHOWS HIGH PRESSURE EXITING TO THE EAST WHILE A
BROAD AREA OF LOW PRESSURE IS DRIFTING TOWARD THE STATE FROM THE
CENTRAL PLAINS. THE INCREASE IN MOISTURE AND LACK OF A CAP HAVE
ALLOWED A FEW CELLS TO DEVELOP THROUGH WESTERN AND NORTHERN PARTS
OF THE AREA THIS AFTERNOON. SO FAR...THE COVERAGE HAS BEEN FAIRLY
SPARSE AND THAT SHOULD BE THE CASE INTO THE EVENING AS THE
DIURNALLY DRIVEN INSTABILITY WANES. TEMPERATURES ARE IN THE MID
80S AT MOST PLACES WITH DEWPOINTS IN THE MID 60S. UNDER PARTLY
SUNNY SKIES WINDS ARE FROM THE SOUTH TO SOUTHWEST AT AROUND 10
KTS.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM
PORTION OF THE FORECAST. THEY ALL DEPICT A BROAD AND RATHER WEAK
TROUGH OVER THE OHIO AND TENNESSEE VALLEYS WITH SLOW MOVING
BATCHES OF ENERGY CAUGHT OVER THE REGION...STUCK BETWEEN
MARGINALLY HIGHER HEIGHTS TO THE WEST AND SOUTHEAST. GIVEN THE
BROAD AGREEMENT WITH THE MODELS HAVE FAVORED THE HIGHER RESOLUTION
GUIDANCE FROM THE HRRR AND NAM12 FOR WEATHER DETAILS.
SENSIBLE WEATHER WILL FEATURE THE ISOLATED TO SCATTERED SHOWERS
AND THUNDERSTORMS DIMINISHING TOWARD AND AFTER SUNSET WITH PARTLY
CLOUDY SKIES ANTICIPATED THROUGH THE NIGHT. PATCHY VALLEY FOG WILL
AGAIN FORM TOWARDS DAWN WITH A SMALL RIDGE TO VALLEY TEMPERATURE
SPLIT LIKELY SETTING UP. SUNDAY WILL SEE A BETTER CHANCE FOR
CONVECTION THROUGHOUT THE CWA WITH MORE CLOUDS HELPING TO KEEP
TEMPERATURES ABOUT A CATEGORY COOLER...BUT WITH CONDITIONS EQUAL
OR EVEN MORE HUMID THAN TODAY. AGAIN PATCHY FOG AND A MINOR RIDGE
TO VALLEY TEMP SPLIT CAN BE EXPECTED LATER SUNDAY NIGHT INTO
MONDAY MORNING.
STARTED WITH THE SHORTBLEND FOR TEMPERATURES...DEWPOINTS...AND
WINDS THROUGH THE EVENING BEFORE GOING WITH THE SUPERBLEND FOR
THE REST OF THE PERIOD. DID ADJUST THE MIN TEMPERATURES EACH NIGHT
FOR TERRAIN DIFFERENCES. AS FOR POPS...ENDED UP CLOSER TO THE
DRIER MAV NUMBERS THROUGHOUT THE SHORT TERM PERIOD.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 330 PM EDT SAT AUG 29 2015
UPPER LEVEL RIDGING WILL REMAIN IN PLACE ACROSS MUCH OF THE EASTERN
CONUS THROUGHOUT THE EXTENDED. MEANWHILE...BOTH THE REMNANTS OF TS
ERIKA AND A WEAK UPPER LEVEL LOW OVER THE MISSISSIPPI RIVER VALLEY
WILL BE THE FEATURES THAT WILL PREVENT US FROM HAVING A COMPLETELY
DRY AND CLEAR WEEK AHEAD. THE UPPER LEVEL RIDGE WILL BE THE MAIN
PLAYER...KEEPING STABLE AIR ACROSS THE REGION DURING THE OVERNIGHT
HOURS AS THE TEMPERATURES COOL. HOWEVER...DURING THE
DAY...INCREASING TEMPERATURES AND THE ABOVE MENTIONED UPPER LEVEL
TRIGGERS WILL RESULT IN SOME ISL TO SCT SHOWERS AND THUNDERSTORMS
ACROSS THE REGION. OUR BEST CHANCES FOR SEEING PRECIP WILL BE DURING
THE DAY MONDAY AS THE LOW THAT WAS TS ERIKA MOVES FAR ENOUGH WEST TO
IMPACT FAR SE KY. IT WILL QUICKLY TRANSITION TO THE NE
HOWEVER...WITH AN APPROACHING SHORTWAVE AND THE DIMINISHING UPPER
LEVEL LOW OVER THE MISSISSIPPI VALLEY SHIFTING EASTWARD ACROSS KY
BY MID WEEK.
MOST OF THE WINDS THROUGH THIS PERIOD WILL BE FROM THE EAST AT THE
SURFACE...AND FROM THE WSW IN THE MID AND UPPER LEVELS. IN OTHER
WORDS...IT IS NOT VERY FAVORABLE FOR SUSTAINABLE THUNDERSTORM
DEVELOPMENT. NOT GOING TO RULE OUT SOME RUMBLES OF THUNDER...SO DID
KEEP MENTION OF TSRA IN FORECAST...BUT DON/T EXPECT STORMS TO BECOME
VERY TALL OR BE FAST MOVERS. NOT TO MENTION LATEST GFS FORECAST
SOUNDINGS DON/T SHOW LI/S BELOW -5C AND CAPE ABOVE 1500 J/KG /WITH
THE EXCEPTION OF MONDAY/...SO NOTHING TOO CONCERNABLE EXPECTED
THROUGH THE WEEK AT THIS POINT.
THE OVERALL RIDGE PATTERN AND LACK OF WIDESPREAD CLOUD COVER WILL
ALLOW TEMPERATURES TO SLOWLY INCREASE EACH DAY THROUGHOUT THE WEEK.
WHILE HIGH TEMPERATURES ON MONDAY WILL STILL BE CONTAINED IN THE LOW
TO MID 80S...WE COULD SEE UPPER 80S BY TUESDAY...AND POSSIBLY EVEN A
90 DEGREE SPOT OR TWO TO ROUND OUT THE WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 133 AM EDT SUN AUG 30 2015
THE MAIN CONCERN AT THE TAF SITES THROUGH DAWN WILL BE THE
DEVELOPMENT OF FOG. THOUGH...WITH SOME CLOUD COVER LINGERING OVER
EAST KENTUCKY...FORECASTING THE ONSET WILL BE QUITE DIFFICULT.
HAVE USED A TEMPO GROUP AT EACH SITE BESIDES JKL AS FOG SHOULD
REMAIN IN THE VALLEYS. ALSO...DESPITE SOME SLIGHTLY HIGHER DEW
POINTS...FOG SHOULD BE MVFR TO IFR AT WORST. WITH GENERALLY LIGHT
WINDS INTO THE DAY WITH SOME INCREASE IN SOUTHWEST FLOW WILL BE
THE NORM. EXPECTING SHOWERS AND THUNDERSTORMS TO DEVELOP BY 18Z
AND PERSIST INTO THE EVENING. COVERAGE CONTINUES TO BE A BIT IN
QUESTION SO WILL GO WITH VCTS AT THE SITES.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SHALLENBERGER
SHORT TERM...GREIF
LONG TERM...JMW
AVIATION...SHALLENBERGER
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1247 PM CDT SUN AUG 30 2015
.AVIATION...MDT CU EVIDENT AS LOW LEVEL MOISTURE BEGINS TO INTRUDE
ON WEAK SOUTHERLY FLOW. NOT EXPECTING MVFR CIG AT LFT TO PERSIST.
THIS FLOW WILL BRING TYPICAL LATE SUMMER PATCHY FOG TO THE PRONE
AIRPORTS LATE TNITE...MVFR/TEMPO IFR LCH AND ARA. AN UPPER TROF
SETTING UP OVER EAST TEXAS IS EXPECTED TO ENHANCE SUFFICIENT
INSTABILITY TO DELIVER SOME SCATTERED TSTMS TO THE BPT TERMINAL
AROUND THIS TIME ON MONDAY...VCTS.
SWEENEY
&&
.PREV DISCUSSION... /ISSUED 1106 AM CDT SUN AUG 30 2015/
DISCUSSION...
ISOLATED SHOWERS AND A THUNDERSTORM OR TWO HAVE DEVELOPED OVER THE
EASTERN COASTAL WATERS ALONG A NE TO SW ORIENTED CONVERGENT
BOUNDARY. RUC APPEARS TO HAVE THE BEST HANDLE ON THIS
ACTIVITY...AND INSISTS THAT IT WILL DIMINISH BY THE AFTERNOON. NOT
QUITE SOLD ON THAT SCENARIO...SO ADDED SMALL POPS FOR THIS AREA
INTO COASTAL SOUTH CENTRAL LA FOR THE REST OF THE DAY. IN ADDITION
TO A DENSER CU FIELD...SEEING SOME HIGH CLOUDS STREAKING EAST
INTO THE REGION AHEAD OF AN UPPER TROF DIGGING INTO EAST TX.
ATMOSPHERE AS DEPICTED ON 12Z KLCH RAOB CONTINUES TO HAVE A
PRONOUNCED DRY LAYER FROM ROUGHLY 5-16K FT...WHICH SHOULD LIMIT
CONVECTION TO PERHAPS A ROGUE SHOWER OR TWO ALONG THE AFTERNOON
SEA BREEZE.
13
PREV DISCUSSION... /ISSUED 614 AM CDT SUN AUG 30 2015/
AVIATION...
A BIT OF BR THRU SUNRISE OTHERWISE VFR FLIGHT RULES EXPECTED
THROUGH THE DAY... AS WINDS SWING AROUND TO THE SE.
PREV DISCUSSION... /ISSUED 304 AM CDT SUN AUG 30 2015/
DISCUSSION...
WX MAP SHOWS WEAK SFC HIGH ACROSS THE CAROLINAS WITH WEAK RIDGING
SW ACROSS OUR REGION THIS MORNING...WITH WEAK SE FLOW ACROSS THE
COASTAL WATERS INTO SE TX. RETREATING NE OF THE REGION...ALLOWING
FOR A RETURN FLOW ACROSS THE NW GULF INTO SE TX. TEMPS A LITTLE
WARMER THIS MORNING...MAINLY IN THE UPPER 60S TO LOWER 70S. PARTLY
CLOUDY CONDITIONS EXPECTED TODAY WITH HIGHS IN THE LOWER/MID
90S...AND MINIMAL CHANCES OF RAIN...LESS THAN 10%
THE WX PATTERN OVER THE REGION WILL BE DOMINATED BY UPPER LOWS
OVER THE NORTHERN GULF THIS WEEK. THE CURRENT UPPER LOW OFF THE
FL PANHANDLE WILL CONTINUE TO LIFT NE TODAY...WITH ANOTHER SHARP
SHORTWAVE TROF EXPECTED TO CUT OFF OVER TX TODAY AND MON AND ONLY
DRIFT EAST THIS WEEK...BASICALLY PARKING OVER SE TX/LA THRU THE
END OF NEXT WEEK. THIS WILL GRADUALLY LEAD TO INCREASING POPS
ACROSS THE REGION STARTING MON WITH A SLIGHT CHANCE...WITH BETTER
CHANCES BEGINNING TUE-SAT. AT THIS TIME...DOESN`T LOOK LIKE A
COMPLETE WASHOUT ANY GIVEN DAY...BUT WILL LIKELY BE ~30-40% EACH
DAY...MAINLY DURING THE LATE MORNING AND AFTERNOON HOURS. TEMPS
WILL CONTINUE MID 70S FOR LOWS...AND LOWER/MID 90S FOR
HIGHS...TYPICAL FOR LATE SUMMER.
DML
MARINE...
A LIGHT EAST TO SOUTHEAST FLOW WILL PREVAIL OVER THE GULF WATERS THROUGH
THE UPCOMING WEEK AS THE REGION REMAINS ON THE SOUTHWEST FLANK OF
HIGH PRESSURE CENTERED OVER THE MID ATLANTIC STATES. THE CHANCE OF
SHOWERS AND THUNDERSTORMS WILL GRADUALLY INCREASE THIS WEEK AS AN
UPPER LEVEL TROUGH OF LOW PRESSURE DIGS INTO EAST TEXAS AND MOVES
SLOWLY EAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 94 70 93 72 / 10 10 20 10
LCH 90 73 90 75 / 10 10 20 20
LFT 91 72 91 73 / 10 10 20 10
BPT 90 74 90 75 / 10 20 20 20
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...NONE.
&&
$$
AVIATION...11
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1106 AM CDT SUN AUG 30 2015
.DISCUSSION...
ISOLATED SHOWERS AND A THUNDERSTORM OR TWO HAVE DEVELOPED OVER THE
EASTERN COASTAL WATERS ALONG A NE TO SW ORIENTED CONVERGENT
BOUNDARY. RUC APPEARS TO HAVE THE BEST HANDLE ON THIS
ACTIVITY...AND INSISTS THAT IT WILL DIMINISH BY THE AFTERNOON. NOT
QUITE SOLD ON THAT SCENARIO...SO ADDED SMALL POPS FOR THIS AREA
INTO COASTAL SOUTH CENTRAL LA FOR THE REST OF THE DAY. IN ADDITION
TO A DENSER CU FIELD...SEEING SOME HIGH CLOUDS STREAKING EAST
INTO THE REGION AHEAD OF AN UPPER TROF DIGGING INTO EAST TX.
ATMOSPHERE AS DEPICTED ON 12Z KLCH RAOB CONTINUES TO HAVE A
PRONOUNCED DRY LAYER FROM ROUGHLY 5-16K FT...WHICH SHOULD LIMIT
CONVECTION TO PERHAPS A ROGUE SHOWER OR TWO ALONG THE AFTERNOON
SEA BREEZE.
13
&&
.PREV DISCUSSION... /ISSUED 614 AM CDT SUN AUG 30 2015/
AVIATION...
A BIT OF BR THRU SUNRISE OTHERWISE VFR FLIGHT RULES EXPECTED
THROUGH THE DAY... AS WINDS SWING AROUND TO THE SE.
PREV DISCUSSION... /ISSUED 304 AM CDT SUN AUG 30 2015/
DISCUSSION...
WX MAP SHOWS WEAK SFC HIGH ACROSS THE CAROLINAS WITH WEAK RIDGING
SW ACROSS OUR REGION THIS MORNING...WITH WEAK SE FLOW ACROSS THE
COASTAL WATERS INTO SE TX. RETREATING NE OF THE REGION...ALLOWING
FOR A RETURN FLOW ACROSS THE NW GULF INTO SE TX. TEMPS A LITTLE
WARMER THIS MORNING...MAINLY IN THE UPPER 60S TO LOWER 70S. PARTLY
CLOUDY CONDITIONS EXPECTED TODAY WITH HIGHS IN THE LOWER/MID
90S...AND MINIMAL CHANCES OF RAIN...LESS THAN 10%
THE WX PATTERN OVER THE REGION WILL BE DOMINATED BY UPPER LOWS
OVER THE NORTHERN GULF THIS WEEK. THE CURRENT UPPER LOW OFF THE
FL PANHANDLE WILL CONTINUE TO LIFT NE TODAY...WITH ANOTHER SHARP
SHORTWAVE TROF EXPECTED TO CUT OFF OVER TX TODAY AND MON AND ONLY
DRIFT EAST THIS WEEK...BASICALLY PARKING OVER SE TX/LA THRU THE
END OF NEXT WEEK. THIS WILL GRADUALLY LEAD TO INCREASING POPS
ACROSS THE REGION STARTING MON WITH A SLIGHT CHANCE...WITH BETTER
CHANCES BEGINNING TUE-SAT. AT THIS TIME...DOESN`T LOOK LIKE A
COMPLETE WASHOUT ANY GIVEN DAY...BUT WILL LIKELY BE ~30-40% EACH
DAY...MAINLY DURING THE LATE MORNING AND AFTERNOON HOURS. TEMPS
WILL CONTINUE MID 70S FOR LOWS...AND LOWER/MID 90S FOR
HIGHS...TYPICAL FOR LATE SUMMER.
DML
MARINE...
A LIGHT EAST TO SOUTHEAST FLOW WILL PREVAIL OVER THE GULF WATERS THROUGH
THE UPCOMING WEEK AS THE REGION REMAINS ON THE SOUTHWEST FLANK OF
HIGH PRESSURE CENTERED OVER THE MID ATLANTIC STATES. THE CHANCE OF
SHOWERS AND THUNDERSTORMS WILL GRADUALLY INCREASE THIS WEEK AS AN
UPPER LEVEL TROUGH OF LOW PRESSURE DIGS INTO EAST TEXAS AND MOVES
SLOWLY EAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 94 70 93 72 / 10 10 20 10
LCH 90 73 90 75 / 10 10 20 20
LFT 91 72 91 73 / 10 10 20 10
BPT 90 74 90 75 / 10 20 20 20
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CARIBOU ME
620 AM EDT SUN AUG 30 2015
.SYNOPSIS...
A WEAK COLD FRONTAL BOUNDARY FROM QUEBEC WILL CROSS THE REGION
TODAY. ANOTHER COLD FRONT IS EXPECTED TO MOVE ACROSS THE REGION BY
MONDAY AFTERNOON...FOLLOWED BY DRIER AND COOLER AIR WITH CANADIAN
HIGH PRESSURE MONDAY NIGHT AND TUESDAY. WEST SOUTHWEST WINDS ON
WEDNESDAY AS THE HIGH MOVES EAST OF THE REGION WILL BRING MUCH
WARMER CONDITIONS ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
615 AM UPDATE...THE BULK OF THE SHOWER ACTIVITY HAS EXITED INTO
NEW BRUNSWICK THIS MORNING. MEANWHILE, A WEAK FRONTAL BOUNDARY
REMAINS DRAPED JUST TO OUR NORTH. THIS BOUNDARY WILL SLIDE SOUTH
THROUGH THE DAY TODAY. THE LATEST HRRR CONTINUES TO TRY TO SHOW
ADDITIONAL PRECIPITATION DEVELOPING LATER THIS MORNING INTO THE
EARLY AFTERNOON ALONG THIS BOUNDARY, BUT STILL BELIEVE THE MODEL
IS OVERDONE. HOWEVER, HAVE KEPT ISOLATED SHOWERS IN FOR NORTHERN
AND EASTERN MAINE THROUGH THE MORNING HOURS TO ACCOUNT FOR THE
SLIGHT CHANCE OF A SPRINKLE OR TWO. OVERALL CHANGES TO THE
FORECAST WERE MINOR WITH THIS UPDATE.
PREVIOUS DISCUSSION...UPPER SHORTWAVE IS RAPIDLY SLIDING ACROSS
SOUTHERN QUEBEC EARLY THIS MORNING. ISOLATED TO SCATTERED SHOWERS
ASSOCIATED WITH THIS FEATURE ARE CURRENTLY PUSHING ACROSS NORTHERN
AND CENTRAL PORTIONS OF OUR FORECAST AREA. THIS PRECIPITATION IS
ALSO MOVING FAIRLY QUICKLY; THE BULK OF THE ACTIVITY IS SLATED TO
MOVE INTO NEW BRUNSWICK BY MID MORNING. THIS IS SUPPORTED BY THE
LATEST HRRR GUIDANCE, WHICH HAS ALL BUT ONE OR TWO SHOWERS EXITING
OUR AREA AROUND 14Z/10 AM. IT IS NOTED THAT THE HRRR ALSO TRIES TO
PRODUCE SOME POP-UP SHOWERS ACROSS THE NORTH THIS AFTERNOON, BUT
WITH DRIER AIR WORKING IN BEHIND THE UPPER WAVE, CURRENT THINKING
IS THAT ALL WE`LL SEE IS SOME CUMULUS CLOUDS WITH PERHAPS SOME
VIRGA. BRIEF RIDGING BUILDS IN FOR LATER THIS AFTERNOON INTO
TONIGHT. HOWEVER, ANOTHER STRONGER UPPER TROUGH AND SURFACE COLD
FRONT WILL APPROACH LATE TONIGHT, WITH SHOWERS MOVING INTO
NORTHERN AREAS AFTER MIDNIGHT. HIGHS TODAY WILL BE IN THE MID 70S
TO AROUND 80 WHILE OVERNIGHT LOWS WILL BE IN THE UPPER 50S TO
LOWER 60S.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
THE L/WV PATTERN OVR NA INTO THE LATE WEEK WILL FEATURE A
BUILDING MDTLY HI AMPLITUDE RIDGE OVR THE ERN GREAT LKS AS AN
UPPER TROF BUILDS SWRD OVR THE W COAST. THIS PLACES NRN/ERN ME IN
THE NE QUADRANT OF THIS RIDGE... MEANING THAT ALTHOUGH TEMPS WILL
LIKELY AVG ABV NORMAL FOR THIS PD...THE REGION WILL BE SUBJECT TO
COLD FRONTAL PASSAGES AS S/WVS CRESTING THE RIDGE IN CNTRL CAN N
OF THE GREAT LKS DROP ESEWRD INTO CAN MARITIMES.
THE FIRST OF THESE S/WVS WILL BE CROSSING JUST N OF THE FA ON MON
BRINGING CLDNSS AND SHWRS TO MSLY NRN PTNS OF THE FA LATE MON MON
THRU MIDDAY AND PERHAPS INTO CNTRL PTNS OF THE FA ERLY TO MID
AFTN. ATTM...WARM MID LVL TEMPS WILL LIKELY KEEP SHWRS FROM
DEVELOPING INTO TSTMS OVR ME...BUT AN ISOLD TSTM CANNOT BE
COMPLETELY RULED OUT TUE AFTN ALG THE NE ME/NW NB BORDER BEFORE
THE S/WV MOVES E OF THE FA LATE MON AFTN. RNFL AMOUNTS ARE LIKELY
TO BE GREATEST IN THE ST JOHN VLY WHERE UP TO A TENTH OF AN INCH
IS POSSIBLE...WITH LESSER OR NO RN AS ONE TRAVERSES FURTHER S.
BEHIND THE FRONT...COOLER AND MUCH DRIER AIR FROM N CNTRL CAN WILL
ADVECT SWRD INTO THE FA MON NGT INTO TUE...WITH DWPTS DROPPING
INTO THE 40S ACROSS NRN AND CNTRL PTNS OF THE FA BY TUE MORN.
TEMPS WILL INITIALLY BE SLOW TO RISE MON MORN WITH MDT LLVL COLD
ADVCN...THEN MAKE MAKE A LITTLE FASTER RECOVERY TO NEAR SEASONAL
NORMS TUE AFTN AS THE LLVL TEMP ADVCN BECOMES MORE NEUTRAL ALL
UNDER SUNNY SKIES. A DRY WARM FRONT WILL CROSS THE REGION BY WED
MORN AS THE SFC HI MOVES S OF THE FA TUE NGT. WINDS...WHICH WILL
BEGIN NEAR CALM TUE EVE WILL SHIFT TO THE LGT SW LATE TUE NGT AS
SKIES BECOME PTLY CLDY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
WITH THE UPPER RIDGE FLEXING SW TO NE OVR THE FA...TEMPS WILL
RAPIDLY RISE ON WED INTO THE 80S OVR THE REGION WITH A WSW WIND
AND PTLY TO MSLY SUNNY SKIES AS HUMIDITY RISES WITH INCREASING SFC
DWPTS REACHING BACK INTO THE LOWER TO MID 60S. A VERY WEAK S/WV
AND ASSOCIATED WEAK COLD FRONT COULD RESULT IN ISOLD TO SCT
MID/LATE AFTN AND ERLY EVE TSTMS...MSLY ACROSS THE N. WHATS LEFT
OF THIS BOUNDARY WILL LIKELY SLIDE S AND W OF THE FA BY
THU...PERHAPS BEING A FOCUS OF SCT AFTN SHWRS/TSTMS ALG THE SW
FLANK OF OUR FA ACROSS WRN AND CNTRL ME. HI TEMPS OVR E CNTRL AND
INTERIOR DOWNEAST AREAS WILL CONT VERY WARM SIMILAR TO WED...BUT
ACROSS THE N SHOULD BE A LITTLE COOLER (UPPER 70S TO LOWER 80S)
AND DRIER AS SFC DWPTS FALL BACK INTO THE 50S BEHIND THE WEAK
COLD FRONT.
AFTWRDS FOR FRI AND SAT...LONGER RANGE MODELS DISAGREE CONCERNING
WHETHER THE FA WILL BE IN SHALLOW COOLER AIR FROM NE CANADA OR
MUCH WARMER AND MORE HUMID AIR FROM THE UPPER MIDWEST. GIVEN
THAT EVEN MINOR DIFFERENCES IN TMG OF WEAK S/WVS WILL BE PIVOTAL
IN DETERMINING THE TMG OF FRONTS ACROSS THE FA...WE KEPT CLOSE TO
THE SUPERBLEND AVG OF LONGER RANGE MODELS FOR HI TEMPS ON FRI AND
SAT WHICH STILL GIVES THE REGION ABV NORMAL TEMPS...BUT WITH LOW
CERTAINTY ON EITHER DAY. FOR NOW...WE KEPT FCST RN POPS EACH DAY.
&&
.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: MAINLY VFR CONDITIONS ARE EXPECTED TODAY AND TONIGHT.
ONLY EXCEPTION WILL BE BRIEF MVFR CEILINGS WILL BE POSSIBLE AT THE
NORTHERN TERMINALS EARLY THIS MORNING AS SHOWERS MOVE THROUGH.
SHORT TERM: MAINLY VFR...XCPT PERHAPS A BRIEF PD OR TWO OF MVFR
CLGS/VSBYS OVR NRN TAF SITES WITH HEAVIER SHWRS ON MON AND AGAIN
WED AFTN/ERLY EVE.
&&
.MARINE...
NEAR TERM: NO HEADLINES WILL BE NEEDED OVER THE WATERS TODAY OR
TONIGHT AS HIGH PRESSURE REMAINS POSITIONED ACROSS THE REGION.
SHORT TERM: NO HDLNS AND LGT SEAS XPCTD...REACHING 2 TO 3 FT OVR
OUR OUTER MZS AND 1 TO 2 FT ALG THE NEAR SHORE WATERS. ABOUT 90
AND 70 PERCENT RESPECTIVELY OF WW3 WV GUIDANCE WAS USED TO PRODUCE
FCST WV HTS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HASTINGS
SHORT TERM...VJN
LONG TERM...VJN
AVIATION...HASTINGS/VJN
MARINE...HASTINGS/VJN
AREA FORECAST DISCUSSION
NWS CARIBOU ME
355 AM EDT SUN AUG 30 2015
.SYNOPSIS...
A WEAK COLD FRONTAL BOUNDARY FROM QUEBEC WILL CROSS THE REGION
TODAY. ANOTHER COLD FRONT IS EXPECTED TO MOVE ACROSS THE REGION BY
MONDAY AFTERNOON...FOLLOWED BY DRIER AND COOLER AIR WITH CANADIAN
HIGH PRESSURE MONDAY NIGHT AND TUESDAY. RETURN WEST... SOUTHWEST
WINDS ON WEDNESDAY AS THE HIGH MOVES EAST OF THE REGION WILL BRING
MUCH WARMER CONDITIONS ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPPER SHORTWAVE IS RAPIDLY SLIDING ACROSS SOUTHERN QUEBEC EARLY
THIS MORNING. ISOLATED TO SCATTERED SHOWERS ASSOCIATED WITH THIS
FEATURE ARE CURRENTLY PUSHING ACROSS NORTHERN AND CENTRAL PORTIONS
OF OUR FORECAST AREA. THIS PRECIPITATION IS ALSO MOVING FAIRLY
QUICKLY; THE BULK OF THE ACTIVITY IS SLATED TO MOVE INTO NEW
BRUNSWICK BY MID MORNING. THIS IS SUPPORTED BY THE LATEST HRRR
GUIDANCE, WHICH HAS ALL BUT ONE OR TWO SHOWERS EXITING OUR AREA
AROUND 14Z/10 AM. IT IS NOTED THAT THE HRRR ALSO TRIES TO PRODUCE
SOME POP-UP SHOWERS ACROSS THE NORTH THIS AFTERNOON, BUT WITH
DRIER AIR WORKING IN BEHIND THE UPPER WAVE, CURRENT THINKING IS
THAT ALL WE`LL SEE IS SOME CUMULUS CLOUDS WITH PERHAPS SOME VIRGA.
BRIEF RIDGING BUILDS IN FOR LATER THIS AFTERNOON INTO TONIGHT.
HOWEVER, ANOTHER STRONGER UPPER TROUGH AND SURFACE COLD FRONT WILL
APPROACH LATE TONIGHT, WITH SHOWERS MOVING INTO NORTHERN AREAS
AFTER MIDNIGHT. HIGHS TODAY WILL BE IN THE MID 70S TO AROUND 80
WHILE OVERNIGHT LOWS WILL BE IN THE UPPER 50S TO LOWER 60S.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
THE L/WV PATTERN OVR NA INTO THE LATE WEEK WILL FEATURE A
BUILDING MDTLY HI AMPLITUDE RIDGE OVR THE ERN GREAT LKS AS AN
UPPER TROF BUILDS SWRD OVR THE W COAST. THIS PLACES NRN/ERN ME IN
THE NE QUADRANT OF THIS RIDGE... MEANING THAT ALTHOUGH TEMPS WILL
LIKELY AVG ABV NORMAL FOR THIS PD...THE REGION WILL BE SUBJECT TO
COLD FRONTAL PASSAGES AS S/WVS CRESTING THE RIDGE IN CNTRL CAN N
OF THE GREAT LKS DROP ESEWRD INTO CAN MARITIMES.
THE FIRST OF THESE S/WVS WILL BE CROSSING JUST N OF THE FA ON MON
BRINGING CLDNSS AND SHWRS TO MSLY NRN PTNS OF THE FA LATE MON MON
THRU MIDDAY AND PERHAPS INTO CNTRL PTNS OF THE FA ERLY TO MID
AFTN. ATTM...WARM MID LVL TEMPS WILL LIKELY KEEP SHWRS FROM
DEVELOPING INTO TSTMS OVR ME...BUT AN ISOLD TSTM CANNOT BE
COMPLETELY RULED OUT TUE AFTN ALG THE NE ME/NW NB BORDER BEFORE
THE S/WV MOVES E OF THE FA LATE MON AFTN. RNFL AMOUNTS ARE LIKELY
TO BE GREATEST IN THE ST JOHN VLY WHERE UP TO A TENTH OF AN INCH
IS POSSIBLE...WITH LESSER OR NO RN AS ONE TRAVERSES FURTHER S.
BEHIND THE FRONT...COOLER AND MUCH DRIER AIR FROM N CNTRL CAN WILL
ADVECT SWRD INTO THE FA MON NGT INTO TUE...WITH DWPTS DROPPING
INTO THE 40S ACROSS NRN AND CNTRL PTNS OF THE FA BY TUE MORN.
TEMPS WILL INITIALLY BE SLOW TO RISE MON MORN WITH MDT LLVL COLD
ADVCN...THEN MAKE MAKE A LITTLE FASTER RECOVERY TO NEAR SEASONAL
NORMS TUE AFTN AS THE LLVL TEMP ADVCN BECOMES MORE NEUTRAL ALL
UNDER SUNNY SKIES. A DRY WARM FRONT WILL CROSS THE REGION BY WED
MORN AS THE SFC HI MOVES S OF THE FA TUE NGT. WINDS...WHICH WILL
BEGIN NEAR CALM TUE EVE WILL SHIFT TO THE LGT SW LATE TUE NGT AS
SKIES BECOME PTLY CLDY.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
WITH THE UPPER RIDGE FLEXING SW TO NE OVR THE FA...TEMPS WILL
RAPIDLY RISE ON WED INTO THE 80S OVR THE REGION WITH A WSW WIND
AND PTLY TO MSLY SUNNY SKIES AS HUMIDITY RISES WITH INCREASING SFC
DWPTS REACHING BACK INTO THE LOWER TO MID 60S. A VERY WEAK S/WV
AND ASSOCIATED WEAK COLD FRONT COULD RESULT IN ISOLD TO SCT
MID/LATE AFTN AND ERLY EVE TSTMS...MSLY ACROSS THE N. WHATS LEFT
OF THIS BOUNDARY WILL LIKELY SLIDE S AND W OF THE FA BY
THU...PERHAPS BEING A FOCUS OF SCT AFTN SHWRS/TSTMS ALG THE SW
FLANK OF OUR FA ACROSS WRN AND CNTRL ME. HI TEMPS OVR E CNTRL AND
INTERIOR DOWNEAST AREAS WILL CONT VERY WARM SIMILAR TO WED...BUT
ACROSS THE N SHOULD BE A LITTLE COOLER (UPPER 70S TO LOWER 80S)
AND DRIER AS SFC DWPTS FALL BACK INTO THE 50S BEHIND THE WEAK
COLD FRONT.
AFTWRDS FOR FRI AND SAT...LONGER RANGE MODELS DISAGREE CONCERNING
WHETHER THE FA WILL BE IN SHALLOW COOLER AIR FROM NE CANADA OR
MUCH WARMER AND MORE HUMID AIR FROM THE UPPER MIDWEST. GIVEN
THAT EVEN MINOR DIFFERENCES IN TMG OF WEAK S/WVS WILL BE PIVOTAL
IN DETERMINING THE TMG OF FRONTS ACROSS THE FA...WE KEPT CLOSE TO
THE SUPERBLEND AVG OF LONGER RANGE MODELS FOR HI TEMPS ON FRI AND
SAT WHICH STILL GIVES THE REGION ABV NORMAL TEMPS...BUT WITH LOW
CERTAINTY ON EITHER DAY. FOR NOW...WE KEPT FCST RN POPS EACH DAY.
&&
.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: MAINLY VFR CONDITIONS ARE EXPECTED TODAY AND TONIGHT.
ONLY EXCEPTION WILL BE BRIEF MVFR CEILINGS WILL BE POSSIBLE AT THE
NORTHERN TERMINALS EARLY THIS MORNING AS SHOWERS MOVE THROUGH.
SHORT TERM: MAINLY VFR...XCPT PERHAPS A BRIEF PD OR TWO OF MVFR
CLGS/VSBYS OVR NRN TAF SITES WITH HEAVIER SHWRS ON MON AND AGAIN
WED AFTN/ERLY EVE.
&&
.MARINE...
NEAR TERM: NO HEADLINES WILL BE NEEDED OVER THE WATERS TODAY OR
TONIGHT AS HIGH PRESSURE REMAINS POSITIONED ACROSS THE REGION.
SHORT TERM: NO HDLNS AND LGT SEAS XPCTD...REACHING 2 TO 3 FT OVR
OUR OUTER MZS AND 1 TO 2 FT ALG THE NEAR SHORE WATERS. ABOUT 90
AND 70 PERCENT RESPECTIVELY OF WW3 WV GUIDANCE WAS USED TO PRODUCE
FCST WV HTS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HASTINGS
SHORT TERM...VJN
LONG TERM...VJN
AVIATION...HASTINGS/VJN
MARINE...HASTINGS/VJN
AREA FORECAST DISCUSSION
NWS CARIBOU ME
349 AM EDT SUN AUG 30 2015
.SYNOPSIS...
A WEAK COLD FRONTAL BOUNDARY FROM QUEBEC WILL CROSS THE REGION
TODAY. ANOTHER COLD FRONT IS EXPECTED TO MOVE ACROSS THE REGION
BY MONDAY AFTERNOON...FOLLOWED BY DRIER AND COOLER AIR WITH
CANADIAN HIGH PRESSURE MONDAY NIGHT AND TUESDAY. RETURN WEST...
SOUTHWEST WINDS ON WEDNESDAY AS THE HIGH MOVES EAST OF THE REGION
WILL BRING MUCH WARMER CONDITIONS ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPPER SHORTWAVE IS RAPIDLY SLIDING ACROSS SOUTHERN QUEBEC EARLY
THIS MORNING. ISOLATED TO SCATTERED SHOWERS ASSOCIATED WITH THIS
FEATURE ARE CURRENTLY PUSHING ACROSS NORTHERN AND CENTRAL PORTIONS
OF OUR FORECAST AREA. THIS PRECIPITATION IS ALSO MOVING FAIRLY
QUICKLY; THE BULK OF THE ACTIVITY IS SLATED TO MOVE INTO NEW
BRUNSWICK BY MID MORNING. THIS IS SUPPORTED BY THE LATEST HRRR
GUIDANCE, WHICH HAS ALL BUT ONE OR TWO SHOWERS EXITING OUR AREA
AROUND 14Z/10 AM. IT IS NOTED THAT THE HRRR ALSO TRIES TO PRODUCE
SOME POP-UP SHOWERS ACROSS THE NORTH THIS AFTERNOON, BUT WITH
DRIER AIR WORKING IN BEHIND THE UPPER WAVE, CURRENT THINKING IS
THAT ALL WE`LL SEE IS SOME CUMULUS CLOUDS WITH PERHAPS SOME VIRGA.
BRIEF RIDGING BUILDS IN FOR LATER THIS AFTERNOON INTO TONIGHT.
HOWEVER, ANOTHER STRONGER UPPER TROUGH AND SURFACE COLD FRONT WILL
APPROACH LATE TONIGHT, WITH SHOWERS MOVING INTO NORTHERN AREAS
AFTER MIDNIGHT. HIGHS TODAY WILL BE IN THE MID 70S TO AROUND 80
WHILE OVERNIGHT LOWS WILL BE IN THE UPPER 50S TO LOWER 60S.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
THE L/WV PATTERN OVR NA WILL FEATURE A BUILDING MDTLY HI AMPLITUDE
RIDGE OVR THE ERN GREAT LKS AS AN UPPER TROF BUILDS SWRD OVR THE W
COAST. THIS PLACES NRN/ERN ME IN THE NE QUADRANT OF THIS RIDGE...
MEANING THAT ALTHOUGH TEMPS WILL LIKELY AVG ABV NORMAL FOR THIS
PD...THE REGION WILL BE SUBJECT TO COLD FRONTAL PASSAGES AS S/WVS
CRESTING THE RIDGE IN CNTRL CAN N OF THE GREAT LKS DROP ESEWRD
INTO CAN MARITIMES.
THE FIRST OF THESE S/WVS WILL BE CROSSING JUST N OF THE FA ON MON
BRINGING CLDNSS AND SHWRS TO MSLY NRN PTNS OF THE FA LATE MON MON
THRU MIDDAY AND PERHAPS INTO CNTRL PTNS OF THE FA ERLY TO MID
AFTN. ATTM...WARM MID LVL TEMPS WILL LIKELY KEEP SHWRS FROM
DEVELOPING INTO TSTMS OVR ME...BUT AN ISOLD TSTM CANNOT BE
COMPLETELY RULED OUT TUE AFTN ALG THE NE ME/NW NB BORDER BEFORE
THE S/WV MOVES E OF THE FA LATE MON AFTN. RNFL AMOUNTS ARE LIKELY
TO BE GREATEST IN THE ST JOHN VLY WHERE UP TO A TENTH OF AN INCH
IS POSSIBLE...WITH LESSER OR NO RN AS ONE TRAVERSES FURTHER S.
BEHIND THE FRONT...COOLER AND MUCH DRIER AIR FROM N CNTRL CAN WILL
ADVECT SWRD INTO THE FA MON NGT INTO TUE...WITH DWPTS DROPPING
INTO THE 40S ACROSS NRN AND CNTRL PTNS OF THE FA BY TUE MORN.
TEMPS WILL INITIALLY BE SLOW TO RISE MON MORN WITH MDT LLVL COLD
ADVCN...THEN MAKE MAKE A LITTLE FASTER RECOVERY TO NEAR SEASONAL
NORMS TUE AFTN AS THE LLVL TEMP ADVCN BECOMES MORE NEUTRAL ALL
UNDER SUNNY SKIES. A DRY WARM FRONT WILL CROSS THE REGION BY WED
MORN AS THE SFC HI MOVES S OF THE FA TUE NGT. WINDS...WHICH WILL
BEGIN NEAR CALM TUE EVE WILL SHIFT TO THE LGT SW LATE TUE NGT AS
SKIES BECOME PTLY CLDY.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
WITH THE UPPER RIDGE FLEXING SW TO NE OVR THE FA...TEMPS WILL
RAPIDLY RISE ON WED INTO THE 80S OVR THE REGION WITH A WSW WIND
AND PTLY TO MSLY SUNNY SKIES AS HUMIDITY RISES WITH INCREASING SFC
DWPTS REACHING BACK INTO THE LOWER TO MID 60S. A VERY WEAK S/WV
AND ASSOCIATED WEAK COLD FRONT COULD RESULT IN ISOLD TO SCT
MID/LATE AFTN AND ERLY EVE TSTMS...MSLY ACROSS THE N. WHATS LEFT
OF THIS BOUNDARY WILL LIKELY SLIDE S AND W OF THE FA BY
THU...PERHAPS BEING A FOCUS OF SCT AFTN SHWRS/TSTMS ALG THE SW
FLANK OF OUR FA ACROSS WRN AND CNTRL ME. HI TEMPS OVR E CNTRL AND
INTERIOR DOWNEAST AREAS WILL CONT VERY WARM SIMILAR TO WED...BUT
ACROSS THE N SHOULD BE A LITTLE COOLER (UPPER 70S TO LOWER 80S)
AND DRIER AS SFC DWPTS FALL BACK INTO THE 50S BEHIND THE WEAK
COLD FRONT.
AFTWRDS FOR FRI AND SAT...LONGER RANGE MODELS DISAGREE CONCERNING
WHETHER THE FA WILL BE IN SHALLOW COOLER AIR FROM NE CANADA OR
MUCH WARMER AND MORE HUMID AIR FROM THE UPPER MIDWEST. GIVEN
THAT EVEN MINOR DIFFERENCES IN TMG OF WEAK S/WVS WILL BE PIVOTAL
IN DETERMINING THE TMG OF FRONTS ACROSS THE FA...WE KEPT CLOSE TO
THE SUPERBLEND AVG OF LONGER RANGE MODELS FOR HI TEMPS ON FRI AND
SAT WHICH STILL GIVES THE REGION ABV NORMAL TEMPS...BUT WITH LOW
CERTAINTY ON EITHER DAY. FOR NOW...WE KEPT FCST RN POPS EACH DAY.
&&
.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: MAINLY VFR CONDITIONS ARE EXPECTED TODAY AND TONIGHT.
ONLY EXCEPTION WILL BE BRIEF MVFR CEILINGS WILL BE POSSIBLE AT THE
NORTHERN TERMINALS EARLY THIS MORNING AS SHOWERS MOVE THROUGH.
SHORT TERM: MAINLY VFR...XCPT PERHAPS A BRIEF PD OR TWO OF MVFR
CLGS/VSBYS OVR NRN TAF SITES WITH HEAVIER SHWRS ON MON AND AGAIN
WED AFTN/ERLY EVE.
&&
.MARINE...
NEAR TERM: NO HEADLINES WILL BE NEEDED OVER THE WATERS TODAY OR
TONIGHT AS HIGH PRESSURE REMAINS POSITIONED ACROSS THE REGION.
SHORT TERM: NO HDLNS AND LGT SEAS XPCTD...REACHING 2 TO 3 FT OVR
OUR OUTER MZS AND 1 TO 2 FT ALG THE NEAR SHORE WATERS. ABOUT 90
AND 70 PERCENT RESPECTIVELY OF WW3 WV GUIDANCE WAS USED TO PRODUCE
FCST WV HTS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HASTINGS
SHORT TERM...VJN
LONG TERM...VJN
AVIATION...HASTINGS/VJN
MARINE...HASTINGS/VJN
AREA FORECAST DISCUSSION
NWS CARIBOU ME
348 AM EDT SUN AUG 30 2015
.SYNOPSIS...
A WEAK COLD FRONTAL BOUNDARY FROM QUEBEC WILL CROSS THE REGION
TODAY. ANOTHER COLD FRONT IS EXPECTED TO MOVE ACROSS THE REGION
BY MONDAY AFTERNOON...FOLLOWED BY DRIER AND COOLER AIR WITH
CANADIAN HIGH PRESSURE MONDAY NIGHT AND TUESDAY. RETURN WEST...
SOUTHWEST WINDS ON WEDNESDAY AS THE HIGH MOVES EAST OF THE REGION
WILL BRING MUCH WARMER CONDITIONS ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPPER SHORTWAVE IS RAPIDLY SLIDING ACROSS SOUTHERN QUEBEC EARLY
THIS MORNING. ISOLATED TO SCATTERED SHOWERS ASSOCIATED WITH THIS
FEATURE ARE CURRENTLY PUSHING ACROSS NORTHERN AND CENTRAL PORTIONS
OF OUR FORECAST AREA. THIS PRECIPITATION IS ALSO MOVING FAIRLY
QUICKLY; THE BULK OF THE ACTIVITY IS SLATED TO MOVE INTO NEW
BRUNSWICK BY MID MORNING. THIS IS SUPPORTED BY THE LATEST HRRR
GUIDANCE, WHICH HAS ALL BUT ONE OR TWO SHOWERS EXITING OUR AREA
AROUND 14Z/10 AM. IT IS NOTED THAT THE HRRR ALSO TRIES TO PRODUCE
SOME POP-UP SHOWERS ACROSS THE NORTH THIS AFTERNOON, BUT WITH
DRIER AIR WORKING IN BEHIND THE UPPER WAVE, CURRENT THINKING IS
THAT ALL WE`LL SEE IS SOME CUMULUS CLOUDS WITH PERHAPS SOME VIRGA.
BRIEF RIDGING BUILDS IN FOR LATER THIS AFTERNOON INTO TONIGHT.
HOWEVER, ANOTHER STRONGER UPPER TROUGH AND SURFACE COLD FRONT WILL
APPROACH LATE TONIGHT, WITH SHOWERS MOVING INTO NORTHERN AREAS
AFTER MIDNIGHT. HIGHS TODAY WILL BE IN THE MID 70S TO AROUND 80
WHILE OVERNIGHT LOWS WILL BE IN THE UPPER 50S TO LOWER 60S.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
THE L/WV PATTERN OVR NA WILL FEATURE A BUILDING MDTLY HI AMPLITUDE
RIDGE OVR THE ERN GREAT LKS AS AN UPPER TROF BUILDS SWRD OVR THE W
COAST. THIS PLACES NRN/ERN ME IN THE NE QUADRANT OF THIS RIDGE...
MEANING THAT ALTHOUGH TEMPS WILL LIKELY AVG ABV NORMAL FOR THIS
PD...THE REGION WILL BE SUBJECT TO COLD FRONTAL PASSAGES AS S/WVS
CRESTING THE RIDGE IN CNTRL CAN N OF THE GREAT LKS DROP ESEWRD
INTO CAN MARITIMES.
THE FIRST OF THESE S/WVS WILL BE CROSSING JUST N OF THE FA ON MON
BRINGING CLDNSS AND SHWRS TO MSLY NRN PTNS OF THE FA LATE MON MON
THRU MIDDAY AND PERHAPS INTO CNTRL PTNS OF THE FA ERLY TO MID
AFTN. ATTM...WARM MID LVL TEMPS WILL LIKELY KEEP SHWRS FROM
DEVELOPING INTO TSTMS OVR ME...BUT AN ISOLD TSTM CANNOT BE
COMPLETELY RULED OUT TUE AFTN ALG THE NE ME/NW NB BORDER BEFORE
THE S/WV MOVES E OF THE FA LATE MON AFTN. RNFL AMOUNTS ARE LIKELY
TO BE GREATEST IN THE ST JOHN VLY WHERE UP TO A TENTH OF AN INCH
IS POSSIBLE...WITH LESSER OR NO RN AS ONE TRAVERSES FURTHER S.
BEHIND THE FRONT...COOLER AND MUCH DRIER AIR FROM N CNTRL CAN WILL
ADVECT SWRD INTO THE FA MON NGT INTO TUE...WITH DWPTS DROPPING
INTO THE 40S ACROSS NRN AND CNTRL PTNS OF THE FA BY TUE MORN.
TEMPS WILL INITIALLY BE SLOW TO RISE MON MORN WITH MDT LLVL COLD
ADVCN...THEN MAKE MAKE A LITTLE FASTER RECOVERY TO NEAR SEASONAL
NORMS TUE AFTN AS THE LLVL TEMP ADVCN BECOMES MORE NEUTRAL ALL
UNDER SUNNY SKIES. A WARM DRY FRONT WILL CROSS THE REGION BY WED
MORN AS THE SFC HI MOVES S OF THE FA TUE NGT. WINDS...WHICH WILL
BEGIN NEAR CALM TUE EVE WILL SHIFT TO THE LGT SW LATE TUE NGT AS
SKIES BECOME PTLY CLDY.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
WITH THE UPPER RIDGE FLEXING SW TO NE OVR THE FA...TEMPS WILL
RAPIDLY RISE ON WED INTO THE 80S OVR THE REGION WITH A WSW WIND
AND PTLY TO MSLY SUNNY SKIES AS HUMIDITY RISES WITH INCREASING SFC
DWPTS REACHING BACK INTO THE LOWER TO MID 60S. A VERY WEAK S/WV
AND ASSOCIATED WEAK COLD FRONT COULD RESULT IN ISOLD TO SCT
MID/LATE AFTN AND ERLY EVE TSTMS...MSLY ACROSS THE N. WHATS LEFT
OF THIS BOUNDARY WILL LIKELY SLIDE S AND W OF THE FA BY
THU...PERHAPS BEING A FOCUS OF SCT AFTN SHWRS/TSTMS ALG THE SW
FLANK OF OUR FA ACROSS WRN AND CNTRL ME. HI TEMPS OVR E CNTRL AND
INTERIOR DOWNEAST AREAS WILL CONT VERY WARM SIMILAR TO WED...BUT
ACROSS THE N SHOULD BE A LITTLE COOLER (UPPER 70S TO LOWER 80S)
AND DRIER AS SFC DWPTS FALL BACK INTO THE 50S BEHIND THE WEAK
COLD FRONT.
AFTWRDS FOR FRI AND SAT...LONGER RANGE MODELS DISAGREE CONCERNING
WHETHER THE FA WILL BE IN SHALLOW COOLER AIR FROM NE CANADA OR
MUCH WARMER AND MORE HUMID AIR FROM THE UPPER MIDWEST. GIVEN
THAT EVEN MINOR DIFFERENCES IN TMG OF WEAK S/WVS WILL BE PIVOTAL
IN DETERMINING THE TMG OF FRONTS ACROSS THE FA...WE KEPT CLOSE TO
THE SUPERBLEND AVG OF LONGER RANGE MODELS FOR HI TEMPS ON FRI AND
SAT WHICH STILL GIVES THE REGION ABV NORMAL TEMPS...BUT WITH LOW
CERTAINTY ON EITHER DAY. FOR NOW...WE KEPT FCST RN POPS EACH DAY.
&&
.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: MAINLY VFR CONDITIONS ARE EXPECTED TODAY AND TONIGHT.
ONLY EXCEPTION WILL BE BRIEF MVFR CEILINGS WILL BE POSSIBLE AT THE
NORTHERN TERMINALS EARLY THIS MORNING AS SHOWERS MOVE THROUGH.
SHORT TERM: MAINLY VFR...XCPT PERHAPS A BRIEF PD OR TWO OF MVFR
CLGS/VSBYS OVR NRN TAF SITES WITH HEAVIER SHWRS ON MON AND AGAIN
WED AFTN/ERLY EVE.
&&
.MARINE...
NEAR TERM: NO HEADLINES WILL BE NEEDED OVER THE WATERS TODAY OR
TONIGHT AS HIGH PRESSURE REMAINS POSITIONED ACROSS THE REGION.
SHORT TERM: NO HDLNS AND LGT SEAS XPCTD...REACHING 2 TO 3 FT OVR
OUR OUTER MZS AND 1 TO 2 FT ALG THE NEAR SHORE WATERS. ABOUT 90
AND 70 PERCENT RESPECTIVELY OF WW3 WV GUIDANCE WAS USED TO PRODUCE
FCST WV HTS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HASTINGS
SHORT TERM...VJN
LONG TERM...VJN
AVIATION...HASTINGS/VJN
MARINE...HASTINGS/VJN
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1244 AM EDT SUN AUG 30 2015
.SYNOPSIS...
A WEAK COLD FRONT FROM QUEBEC WILL CROSS THE REGION SUNDAY
AFTERNOON. ANOTHER COLD FRONT IS EXPECTED TO MOVE ACROSS THE STATE
LATER MONDAY AFTERNOON AND MONDAY NIGHT.
&&
.NEAR TERM /THROUGH TODAY/...
1240 AM UPDATE...ONLY REAL CHANGE WAS TO ADJUST POPS ACCORDING TO
CURRENT RADAR AND HI-RES MODEL TRENDS. BOTH THE HRRR AND THE RAP
BRING PRECIP THROUGH FASTER THAN PREVIOUSLY FORECASTED, AND THE
LATEST RADAR SUPPORTS THIS IDEA. ALSO BROUGHT ISOLATED POPS A BIT
FURTHER SOUTH INTO PORTION OF THE CENTRAL HIGHLANDS THROUGH
DAYBREAK AS THERE ARE SOME DECENT RADAR RETURNS APPROACHING
SOUTHERN PISCATAQUIS COUNTY AT THIS HOUR. MUCH OF THIS IS LIKELY
NOT HITTING THE GROUND, BUT CAN`T RULE OUT A BRIEF SHOWER.
OTHERWISE THE FORECAST IS IN GOOD SHAPE AND NO OTHER CHANGES WERE
NEEDED.
PREVIOUS DISCUSSION...A FEW SHOWERS ARE EXPECTED ACROSS THE
NORTHERN AND WESTERN AREAS LATER TONIGHT INTO EARLY SUNDAY.
CLOUDS WILL CONTINUE TO THICKEN TONIGHT IN ADVANCE OF A COLD FRONT
APCHG FROM QUEBEC. DEWPOINTS IN THE LOW 60S WERE SITTING BACK IN
QUEBEC AHEAD OF THE FRONT. THIS AIRMASS WILL MOVE INTO THE REGION
OVERNIGHT. SOUNDING DATA SHOWED PROFILE MOISTENING UP THROUGH
700MBS ACROSS NORTHERN AND WESTERN AREAS. PWATS CLIMB TO AROUND
1.40 INCHES. INSTABILITY LOOKS TO BE WEAK AND LIMITED TO THE
MAINE-QUEBEC BORDER. BEST CAPES APPEARS TO BE ELEVATED AND LESS
THAN 200 JOULES. THEREFORE, DID NOT INCLUDE ANY MENTION OF THUNDER
BASED ON THIS THINKING. STAYED W/30-40% POPS IN THE AFOREMENTIONED
AREAS THROUGH SUNDAY MORNING. FURTHER S INTO CENTRAL AND DOWNEAST
AREAS JUST SOME CLOUDS AND PERHAPS A SPRINKLE IN THE CENTRAL
HIGHLANDS. DECIDED TO LEAVE OUT ANY MENTION OF SHOWERS IN THESE
AREAS AS CLOUD BASE WILL BE 10K FT AND HIGHER. STAYED W/THE MIDNIGHT
CREW`S THINKING OF OVERNIGHT LOW IN THE MID/UPPER 50S FOR THE NORTH
AND WEST W/UPPER 50S AND LOWER 60S CENTRAL AND DOWNEAST.
USED A CONSENSUS BLEND OF THE NAM12 AND GFS FOR SUNDAY FOR SOME
SHOWERS IN THE MORNING ACROSS THE NORTHERN AREAS AS THE FRONT
SLIDES ACROSS THE REGION. SOUNDINGS DO SUPPORT SOME CAPE OF
300-500 JOULES BUT MOISTURE IS LIMITED BELOW 700MBS AND MID LEVEL
LAPSE RATES ARE MEAGER AT BEST(6.0C/KM). ATTM, DECISION WAS TO
LEAVE OUT THE MENTION OF TSTMS. NOT A WASHOUT BY ANY STRETCH AS
SUNSHINE WILL RETURN AND W/A WEST WIND, AFTERNOON TEMPS SHOULD
CLIMB INTO THE UPPER 70S TO LOWER 80S. QPF THROUGH SUNDAY
EXPECTED TO BE LESS THAN 0.10 INCHES. PARTIAL CLEARING SUNDAY
NIGHT W/THE POTENTIAL FOR FOG. ADDED PATCHY FOG ESPECIALLY
NORTHERN 1/2 OF THE CWA W/A SSW WIND.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
THE MODELS ARE IN GOOD AGREEMENT THROUGH THE PERIOD. A SFC LOW
WITH A CO-LOCATED UPPER LOW PRESSURE TROUGH WILL BE MOVING TO THE
EAST OF THE AREA AT THE START OF THE PERIOD. HIGHER PRESSURE WILL
BUILD ACROSS THE REGION THROUGH THE DAY MON. THE HIGH WILL CREST
OVER THE AREA AT THE END OF THE PERIOD.
LOADED A BLEND OF THE NAM/GFS/GEM/ECMWF FOR T/DP/WND/POP. LOADED
HPC GUIDANCE FOR QPF FIRST 3 PERIOD...A BLEND OF GFS/ECMWF LAST 3
PERIOD. ADD 15 PERCENT TO WNDS FOR GUSTS OVER LAND 25 PERCENT OVER
THE COASTAL WATERS.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
THE EXTENDED MODELS ARE IN GOOD AGREEMENT. A HIGH PRESSURE RIDGE
WILL BE CRESTED OVER THE AREA AT THE START OF THE PERIOD. A UPPER
LEVEL TROUGH WILL MOVE THROUGH THE AREA NORTH TO SOUTH THROUGH THE
DAY WEDNESDAY. BRINGING A CHANCE FOR A FEW SHOWER ACROSS THE
REGION. BY EARLY THURS MRNG THE TROUGH WILL BE OFF THE COAST.
HIGH PRESSURE WILL ONCE AGAIN BUILD ACROSS THE AREA. SAT MRNG
ANOTHER TROUGH WILL MOVE INTO NRN ME FROM THE NE. BY THE END OF
THE PERIOD THE GFS HAS THE TROUGH MOVING BACK NE ACROSS ERN
MAINE... THE ECMWF MOVES IT INTO SW MAINE.
DUE TO UNCERTAINTY IN THE EXTENDED PERIOD USED A BLEND OF THE
MODELS. LOADED NAWAVE 4 FOR SEAS IN THE COASTAL WATERS. ADDED 15
PERCENT TO WINDS FOR GUSTS OVER LAND...25 PERCENT OVER THE COASTAL
WATERS.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: 10PM UPDATE: 00Z TAFS REMAIN ON TRACK WITH VFR
CONDITIONS UNDER MOSTLY MID AND HIGH CLOUDS AS OF 02Z. NO CHANGE
TO REASONING SHOWING LOWERING CATEGORIES AS THE WEAK FRONT PUSHES
THRU OVERNIGHT INTO TOMORROW AM.
ORIGINAL DISCUSSION:
VFR THIS EVENING ACROSS THE NORTHERN TAF SITES DROPPING
TO MVFR LATER TONIGHT AND POSSIBLE IFR NORTH OF KHUL. S OF KHUL,
VFR THROUGH SUNDAY NIGHT. VFR CONDITIONS RETURN FOR NORTHERN AREAS
BY MIDDAY SUNDAY INTO SUNDAY NIGHT. IFR CONDITIONS POSSIBLE LATER
SUNDAY NIGHT W/FOG AND STRATUS AS SSW FLOW SETS UP.
SHORT TERM: A FEW LINGERING CLOUDS ACROSS NRN MAINE AT THE START OF THE
PERIOD OTHERWISE VFR THROUGH WED MRNG ALL SITES...MVFR WED MRNG
ACROSS FVE AND CAR...WED AFTERNOON PQI AND HUL...AND BGR AND BHB
WED EVNG...AS A TROUGH MOVES THROUGH...OTHERWISE VFR.
&&
.MARINE...
NEAR TERM: NO HEADLINES. A S SWELL IN PLACE ATTM W/10-11 SECOND
PERIOD. WAVE HEIGHTS WILL BUILD A BIT W/SW WIND PICKING UP TO 15
KTS EARLY SUNDAY ESPECIALLY OVER THE OUTER WATERS TO 3 FT. OVER
THE INTRA-COASTAL ZONES, 1-2 FT HOLDING W/10 KT WINDS.
SHORT TERM: WINDS AND SEAS BELOW SCA CRITERIA THROUGH THE PERIOD.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HASTINGS/HEWITT
SHORT TERM...NORTON
LONG TERM...NORTON
AVIATION...HASTINGS/HEWITT/NORTON
MARINE...HASTINGS/HEWITT/NORTON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
720 PM EDT MON AUG 31 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 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 720 PM EDT MON AUG 31 2015
EXPECT VFR CONDITIONS TO PREVAIL AT THE SITES THROUGH MUCH OF THE
REST OF THE PERIOD. A WEAK TROUGH WILL NEAR THE WESTERN SITES LATE
TONIGHT AND COULD PRODUCE SOME SPRINKLES...WITH KSAW ONCE AGAIN
SEEING THE POTENTIAL FOR PATCHY GROUND FOG.
&&
.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...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
635 PM EDT SUN AUG 30 2015
.AVIATION...
SCATTERED SHOWERS, ISOLATED THUNDERSTORMS, AND WHAT REMAINS OF
DIURNAL CU WILL DIMINISH OVER THE NEXT COUPLE OF HOURS AS THE
BOUNDARY LAYER STABILIZES. DESPITE A HEALTHY COVERAGE OF MOSTLY
TRANSPARENT CIRRUS, RADIATING CONDITIONS SHOULD BE SUFFICIENTLY
FAVORABLE FOR IFR/LIFR TO DEVELOP LATE TONIGHT AS HIGH PRESSURE
SETTLES OVER THE AREA.
//DTW THRESHOLD PROBABILITIES...
* LOW FOR VSBY AOB 1/2 MILE 09-12Z.
&&
.PREV DISCUSSION...ISSUED 353 PM EDT SUN AUG 30 2015
SHORT TERM... AFTERNOON AND TONIGHT
MID AFTERNOON MESOANALYSIS INDICATES LOWEST 100 MB MLCAPE IN THE
1000-1500 J/KG RANGE FROM THE OHIO BORDER TO ABOUT THE I-96/696
CORRIDOR. THE RADAR TREND HAS BEEN RELATIVELY SOFT GIVEN THE
INSTABILITY SUGGESTING EITHER DAYTIME HEATING NEEDS A LITTLE MORE
TIME OR THAT MID LEVEL SUBSIDENCE IS SUFFICIENT TO CAP DEEP
CONVECTION. MOST RECENT RAP MODEL SOUNDINGS SUPPORT THE LATTER WITH
THE DEPICTION OF SURFACE BASED PARCELS JUST BARELY CLEARING THE
DEEPENING 700-500 MB WARM/STABLE LAYER. AT THE SAME TIME...THE
NEWEST MESOSCALE MODELS ALLOWING EXPLICIT CONVECTION PRODUCE
SCATTERED COVERAGE OF SHOWERS WITH AN ISOLATED THUNDERSTORM DURING
PEAK HEATING FROM LATE AFTERNOON THROUGH EARLY EVENING. THE MOST
PRUDENT APPROACH IS TO ALLOW FOR AN ISOLATED THUNDERSTORM
CONSIDERING A WIND HAZARD IS IN PLAY CONDITIONAL ON STORM
DEVELOPMENT. WV SATELLITE IMAGERY CONTINUES TO SUPPORT MODEL
SOUNDINGS THAT SHOW VERY DRY AIR CENTERED AROUND 500 MB. THE DRY AIR
IS SYMPTOMATIC OF THE LARGER SCALE SUBSIDENCE OCCURRING THROUGH THE
MID LEVELS THAT IS INHIBITING CONVECTION IN THE FIRST PLACE...BUT
WHICH ALSO COULD PROVIDE STRONG NEGATIVE BUOYANCY POTENTIAL SHOULD
INSTABILITY BECOME ADEQUATE FOR DEEP CONVECTION.
POINTS NORTH OF THE I-69 CORRIDOR WILL BE DRY BUT CLOUDY DURING THE
LATE AFTERNOON AND EVENING...AND ANY SHOWERS/STORMS THAT ARE ABLE TO
FORM SOUTH OF THAT LINE WILL QUICKLY DISSIPATE WITH THE LOSS OF
SURFACE HEATING BY MID EVENING. THAT WILL LEAVE A CLEARING TREND TO
OCCUR THROUGH THE OVERNIGHT AS SURFACE HIGH PRESSURE BECOMES RE-
ESTABLISHED OVER LOWER MICHIGAN. THE NORTHERN FRINGES OF THE SURFACE
HIGH REMAINS SET TO ESTABLISH AREAS OF FOG IN SE MICHIGAN TOWARD
SUNRISE AS MIN TEMPS SETTLE IN THE LOWER TO MID 60S. PROJECTED MIN
TEMPS ARE ABOUT A CATEGORY BELOW SURFACE DEWPOINT OBSERVED DURING
THE AFTERNOON TODAY WITH JUST A FEW DEGREES OF DRY ADVECTION
EXPECTED TONIGHT. THIS ADDS SOME CONFIDENCE TO FOG COVERAGE IN OUR
AREA COMBINED WITH THE WIDESPREAD OBSERVATIONAL EVIDENCE OVER
WISCONSIN/IOWA/ILLINOIS FROM THIS MORNING.
LONG TERM...MONDAY THROUGH SATURDAY
THE ANTICIPATED WAVELENGTH BROADENING OF UPPER LEVEL RIDGE IS
FORECASTED TO ACCELERATE MONDAY WITH A CENTROID OF THE UPPER LEVEL
GEOPOTENTIAL HEIGHT MAX BREAKING OFF OF THE RIDGE PEAK AND ROLLING
EASTWARD INTO MUCH OF EASTERN CANADA. MODELS FORECAST A WEAKNESS
DEVELOPING WITHIN THE RIDGE FOR THE BEGINNING OF THE WEEK
PERIOD....BUT ALL INDICATIONS ARE THE SLIGHTLY COOLER MIDLEVEL
TEMPERATURES WILL REMAIN CONFINED TO THE OHIO RIVER VALLEY. A VERY
WEAK BAROCLINIC ZONE...WITH NO JET SUPPORT ALOFT...WILL MATERIALIZE
TO SOUTH OF THE OHIO/MICHIGAN BORDER. IT IS ALONG THIS FEATURE AND
TO THE SOUTH WHERE A BETTER CHANCE EXISTS FOR A POP-UP SHOWER OR
THUNDERSTORM. FOR SOUTHEASTERN MICHIGAN THE FORECAST WILL REMAIN
DRY. WITH THE RIDGE EXPANDING EAST...THE HEAT AND UNCOMFORTABLE
CONDITIONS WILL GET STARTED WITH TEMPERATURES AND DEWPOINTS
COMBINING TO PUSH HEAT INDICES INTO THE MID TO UPPER 80S FOR MONDAY.
THE WEAK TEMPERATURE DISCONTINUITY OR FRONTAL ZONE IS THEN
FORECASTED TO LIFT SLIGHTLY NORTHWARD TUESDAY. THIS WILL OCCUR HAS
LOOSELY DEFINED AND WEAK SHORTWAVE ENERGY CONSOLIDATES INTO SOME
ORGANIZATION OVER GREATER PORTIONS OF OHIO AND INDIANA. A PLAN
VIEW OF MIDLEVEL OR 700 MB TEMPERATURES SHOWS THIS WITH SOME SUB
7C 700 MB TEMPERATURES LIFTING ACROSS THE STATELINE INTO FAR
SOUTHEASTERN MICHIGAN. IT IS A STEEP LAPSE RATE POCKET FROM
800-700MB THAT MAY THEN ALLOW FOR SOME CONVECTIVE SHOWER/TSTORM
DEVELOPMENT TUESDAY AFTERNOON AS THE BOUNDARY LIFTS NORTHWARD.
WILL REFRAIN FROM ADDING A PRECIPITATION MENTION THIS FORECAST
ISSUANCE AS POTENTIAL STILL APPEARS TO BE LESS THAN 20 PERCENT.
WORKING OFF WARMER MINS...TEMPERATURES ARE EXPECTED TO MODERATE A
FEW MORE DEGREES WITH HIGHS EASILY REACHING THE MIDDLE TO UPPER
80S TUESDAY AFTERNOON. HEAT INDICES ARE FORECASTED TO ECLIPSE THE
90 DEGREE MARK.
EXTENDED...BY THE MIDDLE OF NEXT WEEK...SOUTHEAST MICHIGAN WILL BE
FIRMLY UNDER THE UPPER LEVEL RIDGING AND SOUTHERLY FLOW. THIS WILL
BRING A CONTINUATION OF ABOVE NORMAL TEMPERATURES ALONG WITH DRY
CONDITIONS WHICH WILL PERSIST THROUGH THE REMAINDER OF THE WEEK AND
INTO THE WEEKEND.
MARINE...
VERY QUIET MARINE WEATHER WILL PERSIST ON THE GREAT LAKES THROUGH
MUCH OF THE UPCOMING WEEK. A STRONG RIDGE OF UPPER LEVEL HIGH
PRESSURE WILL MAINTAIN LIGHT FLOW AND A GENERAL SOUTHWEST WIND
DIRECTION.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....JVC
SHORT TERM...BT
LONG TERM....CB/SS
MARINE.......CB
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
353 PM EDT SUN AUG 30 2015
.SHORT TERM... AFTERNOON AND TONIGHT
MID AFTERNOON MESOANALYSIS INDICATES LOWEST 100 MB MLCAPE IN THE
1000-1500 J/KG RANGE FROM THE OHIO BORDER TO ABOUT THE I-96/696
CORRIDOR. THE RADAR TREND HAS BEEN RELATIVELY SOFT GIVEN THE
INSTABILITY SUGGESTING EITHER DAYTIME HEATING NEEDS A LITTLE MORE
TIME OR THAT MID LEVEL SUBSIDENCE IS SUFFICIENT TO CAP DEEP
CONVECTION. MOST RECENT RAP MODEL SOUNDINGS SUPPORT THE LATTER WITH
THE DEPICTION OF SURFACE BASED PARCELS JUST BARELY CLEARING THE
DEEPENING 700-500 MB WARM/STABLE LAYER. AT THE SAME TIME...THE
NEWEST MESOSCALE MODELS ALLOWING EXPLICIT CONVECTION PRODUCE
SCATTERED COVERAGE OF SHOWERS WITH AN ISOLATED THUNDERSTORM DURING
PEAK HEATING FROM LATE AFTERNOON THROUGH EARLY EVENING. THE MOST
PRUDENT APPROACH IS TO ALLOW FOR AN ISOLATED THUNDERSTORM
CONSIDERING A WIND HAZARD IS IN PLAY CONDITIONAL ON STORM
DEVELOPMENT. WV SATELLITE IMAGERY CONTINUES TO SUPPORT MODEL
SOUNDINGS THAT SHOW VERY DRY AIR CENTERED AROUND 500 MB. THE DRY AIR
IS SYMPTOMATIC OF THE LARGER SCALE SUBSIDENCE OCCURRING THROUGH THE
MID LEVELS THAT IS INHIBITING CONVECTION IN THE FIRST PLACE...BUT
WHICH ALSO COULD PROVIDE STRONG NEGATIVE BUOYANCY POTENTIAL SHOULD
INSTABILITY BECOME ADEQUATE FOR DEEP CONVECTION.
POINTS NORTH OF THE I-69 CORRIDOR WILL BE DRY BUT CLOUDY DURING THE
LATE AFTERNOON AND EVENING...AND ANY SHOWERS/STORMS THAT ARE ABLE TO
FORM SOUTH OF THAT LINE WILL QUICKLY DISSIPATE WITH THE LOSS OF
SURFACE HEATING BY MID EVENING. THAT WILL LEAVE A CLEARING TREND TO
OCCUR THROUGH THE OVERNIGHT AS SURFACE HIGH PRESSURE BECOMES RE-
ESTABLISHED OVER LOWER MICHIGAN. THE NORTHERN FRINGES OF THE SURFACE
HIGH REMAINS SET TO ESTABLISH AREAS OF FOG IN SE MICHIGAN TOWARD
SUNRISE AS MIN TEMPS SETTLE IN THE LOWER TO MID 60S. PROJECTED MIN
TEMPS ARE ABOUT A CATEGORY BELOW SURFACE DEWPOINT OBSERVED DURING
THE AFTERNOON TODAY WITH JUST A FEW DEGREES OF DRY ADVECTION
EXPECTED TONIGHT. THIS ADDS SOME CONFIDENCE TO FOG COVERAGE IN OUR
AREA COMBINED WITH THE WIDESPREAD OBSERVATIONAL EVIDENCE OVER
WISCONSIN/IOWA/ILLINOIS FROM THIS MORNING.
&&
.LONG TERM...MONDAY THROUGH SATURDAY
THE ANTICIPATED WAVELENGTH BROADENING OF UPPER LEVEL RIDGE IS
FORECASTED TO ACCELERATE MONDAY WITH A CENTROID OF THE UPPER LEVEL
GEOPOTENTIAL HEIGHT MAX BREAKING OFF OF THE RIDGE PEAK AND ROLLING
EASTWARD INTO MUCH OF EASTERN CANADA. MODELS FORECAST A WEAKNESS
DEVELOPING WITHIN THE RIDGE FOR THE BEGINNING OF THE WEEK
PERIOD....BUT ALL INDICATIONS ARE THE SLIGHTLY COOLER MIDLEVEL
TEMPERATURES WILL REMAIN CONFINED TO THE OHIO RIVER VALLEY. A VERY
WEAK BAROCLINIC ZONE...WITH NO JET SUPPORT ALOFT...WILL MATERIALIZE
TO SOUTH OF THE OHIO/MICHIGAN BORDER. IT IS ALONG THIS FEATURE AND
TO THE SOUTH WHERE A BETTER CHANCE EXISTS FOR A POP-UP SHOWER OR
THUNDERSTORM. FOR SOUTHEASTERN MICHIGAN THE FORECAST WILL REMAIN
DRY. WITH THE RIDGE EXPANDING EAST...THE HEAT AND UNCOMFORTABLE
CONDITIONS WILL GET STARTED WITH TEMPERATURES AND DEWPOINTS
COMBINING TO PUSH HEAT INDICES INTO THE MID TO UPPER 80S FOR MONDAY.
THE WEAK TEMPERATURE DISCONTINUITY OR FRONTAL ZONE IS THEN
FORECASTED TO LIFT SLIGHTLY NORTHWARD TUESDAY. THIS WILL OCCUR HAS
LOOSELY DEFINED AND WEAK SHORTWAVE ENERGY CONSOLIDATES INTO SOME
ORGANIZATION OVER GREATER PORTIONS OF OHIO AND INDIANA. A PLAN
VIEW OF MIDLEVEL OR 700 MB TEMPERATURES SHOWS THIS WITH SOME SUB
7C 700 MB TEMPERATURES LIFTING ACROSS THE STATELINE INTO FAR
SOUTHEASTERN MICHIGAN. IT IS A STEEP LAPSE RATE POCKET FROM
800-700MB THAT MAY THEN ALLOW FOR SOME CONVECTIVE SHOWER/TSTORM
DEVELOPMENT TUESDAY AFTERNOON AS THE BOUNDARY LIFTS NORTHWARD.
WILL REFRAIN FROM ADDING A PRECIPITATION MENTION THIS FORECAST
ISSUANCE AS POTENTIAL STILL APPEARS TO BE LESS THAN 20 PERCENT.
WORKING OFF WARMER MINS...TEMPERATURES ARE EXPECTED TO MODERATE A
FEW MORE DEGREES WITH HIGHS EASILY REACHING THE MIDDLE TO UPPER
80S TUESDAY AFTERNOON. HEAT INDICES ARE FORECASTED TO ECLIPSE THE
90 DEGREE MARK.
.EXTENDED...BY THE MIDDLE OF NEXT WEEK...SOUTHEAST MICHIGAN WILL BE
FIRMLY UNDER THE UPPER LEVEL RIDGING AND SOUTHERLY FLOW. THIS WILL
BRING A CONTINUATION OF ABOVE NORMAL TEMPERATURES ALONG WITH DRY
CONDITIONS WHICH WILL PERSIST THROUGH THE REMAINDER OF THE WEEK AND
INTO THE WEEKEND.
&&
.MARINE...
VERY QUIET MARINE WEATHER WILL PERSIST ON THE GREAT LAKES THROUGH
MUCH OF THE UPCOMING WEEK. A STRONG RIDGE OF UPPER LEVEL HIGH
PRESSURE WILL MAINTAIN LIGHT FLOW AND A GENERAL SOUTHWEST WIND
DIRECTION.
&&
.AVIATION...ISSUED 117 PM EDT SUN AUG 30 2015
STUBBORN MVFR CEILING...MOSTLY FROM PTK NORTHWARD...IS ASSOCIATED
WITH A FILLING WARM FRONT/TROUGH THAT IS MOVING SLOWLY EASTWARD
DURING THE AFTERNOON. THE DEPARTURE OF THE FRONTAL REMNANTS WILL
ALLOW LOW END VFR CEILING TO DEVELOP AT ALL LOCATIONS AS SURFACE
HEATING HELPS LIFT THE CLOUD BASE. THAT WILL LEAVE COVERAGE OF
SHOWERS OR ISOLATED THUNDERSTORMS TO BE MONITORED THROUGH MID
EVENING. EXPECTATION REMAINS THAT COVERAGE WILL BE TOO LOW TO
PINPOINT AT A TERMINAL LOCATION DEFERRING TO LATER UPDATES AS RADAR
TRENDS BECOME MORE CLEAR. DIMINISHING CLOUDS DURING THE EVENING WILL
LIKELY LEAD TO FOG AGAIN LATE TONIGHT. THERE WAS QUITE A BIT OF
IFR/LIFR COVERAGE OVER WISCONSIN/IOWA/ILLINOIS TO GUIDE POTENTIAL AS
THE NORTHERN FRINGES OF HIGH PRESSURE SETTLES OVER SE MICHIGAN
THROUGH MONDAY MORNING.
FOR DTW... LINGERING WARMTH AND HUMIDITY WILL PROMOTE LIFTING AND
PERSISTENCE OF CEILING AROUND 4500 FT THROUGH THE AFTERNOON FOLLOWED
BY A GRADUAL CLEARING TREND DURING THE EVENING. CLEAR SKY AND LIGHT
WIND WILL MAKE IFR FOG LIKELY AROUND SUNRISE MONDAY.
//DTW THRESHOLD PROBABILITIES...
* HIGH FOR CEILING 5000 FT OR LESS DURING THE AFTERNOON.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
SHORT TERM...BT
LONG TERM....CB/SS
MARINE.......CB
AVIATION.....BT
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
117 PM EDT SUN AUG 30 2015
.AVIATION...
STUBBORN MVFR CEILING...MOSTLY FROM PTK NORTHWARD...IS ASSOCIATED
WITH A FILLING WARM FRONT/TROUGH THAT IS MOVING SLOWLY EASTWARD
DURING THE AFTERNOON. THE DEPARTURE OF THE FRONTAL REMNANTS WILL
ALLOW LOW END VFR CEILING TO DEVELOP AT ALL LOCATIONS AS SURFACE
HEATING HELPS LIFT THE CLOUD BASE. THAT WILL LEAVE COVERAGE OF
SHOWERS OR ISOLATED THUNDERSTORMS TO BE MONITORED THROUGH MID
EVENING. EXPECTATION REMAINS THAT COVERAGE WILL BE TOO LOW TO
PINPOINT AT A TERMINAL LOCATION DEFERRING TO LATER UPDATES AS RADAR
TRENDS BECOME MORE CLEAR. DIMINISHING CLOUDS DURING THE EVENING WILL
LIKELY LEAD TO FOG AGAIN LATE TONIGHT. THERE WAS QUITE A BIT OF
IFR/LIFR COVERAGE OVER WISCONSIN/IOWA/ILLINOIS TO GUIDE POTENTIAL AS
THE NORTHERN FRINGES OF HIGH PRESSURE SETTLES OVER SE MICHIGAN
THROUGH MONDAY MORNING.
FOR DTW... LINGERING WARMTH AND HUMIDITY WILL PROMOTE LIFTING AND
PERSISTENCE OF CEILING AROUND 4500 FT THROUGH THE AFTERNOON FOLLOWED
BY A GRADUAL CLEARING TREND DURING THE EVENING. CLEAR SKY AND LIGHT
WIND WILL MAKE IFR FOG LIKELY AROUND SUNRISE MONDAY.
//DTW THRESHOLD PROBABILITIES...
* HIGH FOR CEILING 5000 FT OR LESS DURING THE AFTERNOON.
&&
.PREV DISCUSSION...ISSUED 1123 AM EDT SUN AUG 30 2015
UPDATE...
HELD THE LINE FROM THE MORNING FORECAST PACKAGE ON THUNDERSTORM
POTENTIAL FOR THIS AFTERNOON. THE SUBDUED/ISOLATED MENTION REMAINS
ON TARGET MAINLY AS DAYTIME HEATING ACTS ON LINGERING LOW LEVEL
MOISTURE. THE 12Z DTX SOUNDING INDICATES THE BEGINNING OF CAP
DEVELOPMENT UNDER INFLUENCE OF SUBSIDENCE TRAILING THE UPPER LEVEL
TROUGH AXIS AS IT EXITS LOWER MICHIGAN. THE RACE IS ALSO ON
BETWEEN SURFACE HEATING AND NEGATIVE THETA-E ADVECTION AROUND 850
MB. THIS PROCESS WILL GRADUALLY REDUCE THE DEPTH OF MOISTURE
INDICATED IN THE SOUNDING. MAINTENANCE OF ISOLATED THUNDERSTORM
COVERAGE ALONG AND SOUTH OF INTERSTATE 69 IS THEN A NOD TO CONTINUED
DEPICTION OF DEVELOPMENT IN EVEN THE MOST RECENT MESOSCALE MODEL
RUNS. THE LATEST RAP SUGGESTS SURFACE BASED CAPE RISING TO ABOUT
1200 J/KG AS LONG AS DEWPOINT CAN HOLD IN THE MID 60S. CONVECTION
MAY END UP BEING MORE OF A MODERATE DEPTH SHOWER RATHER THAN A
THUNDERSTORM ASSUMING MID LEVEL SUBSIDENCE CONTINUES TO EVOLVE. IF
CONVECTION CAN BREACH THE WARM LAYER AND REACH -20C/THUNDER THEN
SOME POTENTIAL FOR PRECIP LOADED WIND GUSTS WILL EXIST DUE TO
ENTRAINMENT OF MID TO UPPER LEVEL DRY AIR INDICATED IN THE
SOUNDING AND WV IMAGERY. OTHERWISE...JUST A LOCALLY HEAVY DOWNPOUR
EXPECTED THROUGH THE PEAK HEATING CYCLE INTO EARLY EVENING.
PREV DISCUSSION...ISSUED 302 AM EDT SUN AUG 30 2015
SHORT TERM... TODAY AND TONIGHT
MOIST AIRMASS IN PLACE OVER SOUTHEAST MICHIGAN EARLY THIS
MORNING...AS 00Z DTX SOUNDING REVEALED A 700 MB DEW PT OF 4
C...850 MB DEW PT OF 12 C...ALONG WITH A PW VALUE OF 1.6 INCHES.
SHEARED OUT SHORTWAVE/PV WILL SLOWLY BE EXITING THE CENTRAL GREAT
LAKES...BUT LAST VESTIGE OF 850-700 MB THETA-E AXIS STILL PROVE
SUFFICIENT FOR ISOLATED-SCATTERED LIGHT SHOWERS THIS MORNING BEFORE
DRIER AIR ATTEMPTS TO SLOWLY FILTER INTO SOUTHERN LOWER MICHIGAN
THROUGH THE DAY...BUT UNCERTAIN WE WILL BE ABLE TO SCOUR OUT THE LOW
LEVEL MOISTURE...AS 00Z NAM MAINTAINS HIGHER RH VALUES IN THE 925-
850 MB LAYER. WITH 500 MB TEMPS FALLING UP TO 2 C DEGREES...SURFACE
BASED INSTABILITY/CAPE IS PROGGED TO RISE TO AROUND 750 J/G...PER
00Z GFS...BUT 1000-2000 J/KG PER 00Z NAM...AS SURFACE DEW PTS REMAIN
SOLIDLY IN THE 60S. HOWEVER...700 MB TEMPS WILL BE RISING TO AROUND
9 C NORTH OF I-69...WHICH SHOULD ULTIMATELY PROVIDE A SUFFICIENT
CAP. SOUTH OF I-69 IS WHERE COOLER MID LEVELS PERSIST LONGER AND
WHERE A SLIGHT/LOW CHANCE OF SHOWERS/THUNDERSTORMS WILL BE CARRIED
FOR THE AFTERNOON HOURS. MINIMAL CONCERNS FOR SEVERE WEATHER WITH
WEAK WIND FIELDS...IF IN FACT A CELL IS EVEN ABLE TO GO UP.
BASED ON PESKY CLOUDS EXPECTED TODAY...WILL HOLD MAXES AROUND 80
DEGREES...BUT POTENTIAL FOR WARMER TEMPS IS THERE WITH 850 MB TEMPS
OF 16 C. LOW LEVEL MOISTURE/ELEVATED DEW PTS HOLDING IN THE LOWER
60S TONIGHT SHOULD SET THE STAGE FOR SOME FOG AS SKIES BECOME MAINLY
CLEAR WITH LIGHT/CALM WINDS IN PLACE.
LONG TERM...MONDAY THROUGH SATURDAY
SOUTHERN PLAINS UPPER RIDGE WILL UNDERGO STEADY DOWNSTREAM
AMPLIFICATION OVER THE NEXT 48 HOURS...IN RESPONSE TO SUBSTANTIAL
HEIGHT FALLS WORKING INTO THE WESTERN CONUS. THIS PROCESS WILL
EFFECTIVELY CENTER AN UPPER LEVEL ANTICYCLONE OVER SE MICHIGAN BY
MONDAY. A HIGH DEGREE OF STABILITY UNDER THE ATTENDANT MINIMUM IN
THETA-E AND AN ELEVATED MID LEVEL TEMPERATURE PROFILE WILL YIELD
PLENTY OF SUNSHINE...AND NO REAL OPPORTUNITY FOR CONVECTIVE
DEVELOPMENT. THE INCREASE IN THICKNESSES AND GENERALLY LIGHT
SOUTHWEST FLOW WILL PROVIDE A NOTED UPTICK IN TEMPERATURES RELATIVE
TO TODAY...WITH DAYTIME READINGS REACHING THE MID 80S.
UPPER RIDGING TO REMAIN THE PRIMARY GOVERNING FEATURE THROUGH THE
REMAINDER OF THE UPCOMING WORK WEEK. THIS WILL TRANSLATE INTO A
RELATIVELY BENIGN STRETCH OF WEATHER CONDITIONS...WITH ABOVE NORMAL
WARMTH AND LIMITED /IF ANY/ POTENTIAL FOR CONVECTION. THE RIDGE
AXIS MAY LOSE SOME DEFINITION BY MIDWEEK AS A WEAK HEIGHT FALL
CENTER DRIFTS THROUGH THE OHIO VALLEY...WITH A CORRESPONDING GRADUAL
INCREASE IN THETA-E DURING THIS TIME. PLAUSIBLE SCENARIO THAT WEAK
CVA WORKING THROUGH ALONG THE NORTH END OF THIS FEATURE PROVIDES A
LOCALIZED/BRIEF WINDOW FOR ASCENT...MEDIUM RANGE GUIDANCE STILL
CENTERING ON WEDNESDAY. LOW END POTENTIAL AT THIS STAGE GIVEN AN
OTHERWISE LACKLUSTER LOOKING FORCING/WIND FIELD.
MARINE...
BENIGN MARINE WEATHER WILL CONTINUE ACROSS THE GREAT LAKES REGION
THROUGH MUCH OF THE UPCOMING WEEK. A STRONG RIDGE OF UPPER LEVEL
HIGH PRESSURE WILL MAINTAIN LIGHT FLOW AND A GENERAL SOUTHWEST WIND
DIRECTION.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....BT
UPDATE.......BT
SHORT TERM...SF
LONG TERM....MR
MARINE.......MR
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1123 AM EDT SUN AUG 30 2015
.UPDATE...
HELD THE LINE FROM THE MORNING FORECAST PACKAGE ON THUNDERSTORM
POTENTIAL FOR THIS AFTERNOON. THE SUBDUED/ISOLATED MENTION REMAINS
ON TARGET MAINLY AS DAYTIME HEATING ACTS ON LINGERING LOW LEVEL
MOISTURE. THE 12Z DTX SOUNDING INDICATES THE BEGINNING OF CAP
DEVELOPMENT UNDER INFLUENCE OF SUBSIDENCE TRAILING THE UPPER LEVEL
TROUGH AXIS AS IT EXITS LOWER MICHIGAN. THE RACE IS ALSO ON
BETWEEN SURFACE HEATING AND NEGATIVE THETA-E ADVECTION AROUND 850
MB. THIS PROCESS WILL GRADUALLY REDUCE THE DEPTH OF MOISTURE
INDICATED IN THE SOUNDING. MAINTENANCE OF ISOLATED THUNDERSTORM
COVERAGE ALONG AND SOUTH OF INTERSTATE 69 IS THEN A NOD TO CONTINUED
DEPICTION OF DEVELOPMENT IN EVEN THE MOST RECENT MESOSCALE MODEL
RUNS. THE LATEST RAP SUGGESTS SURFACE BASED CAPE RISING TO ABOUT
1200 J/KG AS LONG AS DEWPOINT CAN HOLD IN THE MID 60S. CONVECTION
MAY END UP BEING MORE OF A MODERATE DEPTH SHOWER RATHER THAN A
THUNDERSTORM ASSUMING MID LEVEL SUBSIDENCE CONTINUES TO EVOLVE. IF
CONVECTION CAN BREACH THE WARM LAYER AND REACH -20C/THUNDER THEN
SOME POTENTIAL FOR PRECIP LOADED WIND GUSTS WILL EXIST DUE TO
ENTRAINMENT OF MID TO UPPER LEVEL DRY AIR INDICATED IN THE
SOUNDING AND WV IMAGERY. OTHERWISE...JUST A LOCALLY HEAVY DOWNPOUR
EXPECTED THROUGH THE PEAK HEATING CYCLE INTO EARLY EVENING.
&&
.AVIATION...ISSUED 545 AM EDT SUN AUG 30 2015
LINGERING LOW LEVEL MOISTURE WITH DRY AIR IN THE MID LEVELS
ATTEMPTING TO MOVE INTO SOUTHEAST MICHIGAN TODAY. ISOLATED-SCATTERED
LIGHT SHOWERS STILL AROUND...WITH A REMOTE CHANCE OF A THUNDERSTORM.
FORECAST CEILINGS WILL HINGE ON THE EXTENT OF LOWER CLOUDS AND FOG
DEVELOPING NEAR SUNRISE. WHATEVER IFR FOG AND STRATUS AROUND WILL
GRADUALLY LIFT INTO LOW VFR DECK BY EARLY AFTERNOON...AND LIKELY
LINGERING MOST OF THE DAY. CLEARING SKIES DURING THE EVENING HOURS
EXPECTED TO YIELD FOG AGAIN LATE TONIGHT...BUT SHOULD BE
SHALLOWER...AND HAVE GONE WITH 3SM FOR NOW.
FOR DTW...SHOULD HAVE MVFR FOG TO START THE DAY...BUT HAVE BACKED
OFF ON THE IFR CEILING. CEILINGS AROUND OR JUST BELOW 5000 FEET
EXPECTED THROUGH THE DAY...BUT CLEARING DURING EARLY EVENING HOURS.
//DTW THRESHOLD PROBABILITIES...
* HIGH FOR CIG AOB 5KFT TODAY.
&&
.PREV DISCUSSION...ISSUED 302 AM EDT SUN AUG 30 2015
SHORT TERM... TODAY AND TONIGHT
MOIST AIRMASS IN PLACE OVER SOUTHEAST MICHIGAN EARLY THIS
MORNING...AS 00Z DTX SOUNDING REVEALED A 700 MB DEW PT OF 4
C...850 MB DEW PT OF 12 C...ALONG WITH A PW VALUE OF 1.6 INCHES.
SHEARED OUT SHORTWAVE/PV WILL SLOWLY BE EXITING THE CENTRAL GREAT
LAKES...BUT LAST VESTIGE OF 850-700 MB THETA-E AXIS STILL PROVE
SUFFICIENT FOR ISOLATED-SCATTERED LIGHT SHOWERS THIS MORNING BEFORE
DRIER AIR ATTEMPTS TO SLOWLY FILTER INTO SOUTHERN LOWER MICHIGAN
THROUGH THE DAY...BUT UNCERTAIN WE WILL BE ABLE TO SCOUR OUT THE LOW
LEVEL MOISTURE...AS 00Z NAM MAINTAINS HIGHER RH VALUES IN THE 925-
850 MB LAYER. WITH 500 MB TEMPS FALLING UP TO 2 C DEGREES...SURFACE
BASED INSTABILITY/CAPE IS PROGGED TO RISE TO AROUND 750 J/G...PER
00Z GFS...BUT 1000-2000 J/KG PER 00Z NAM...AS SURFACE DEW PTS REMAIN
SOLIDLY IN THE 60S. HOWEVER...700 MB TEMPS WILL BE RISING TO AROUND
9 C NORTH OF I-69...WHICH SHOULD ULTIMATELY PROVIDE A SUFFICIENT
CAP. SOUTH OF I-69 IS WHERE COOLER MID LEVELS PERSIST LONGER AND
WHERE A SLIGHT/LOW CHANCE OF SHOWERS/THUNDERSTORMS WILL BE CARRIED
FOR THE AFTERNOON HOURS. MINIMAL CONCERNS FOR SEVERE WEATHER WITH
WEAK WIND FIELDS...IF IN FACT A CELL IS EVEN ABLE TO GO UP.
BASED ON PESKY CLOUDS EXPECTED TODAY...WILL HOLD MAXES AROUND 80
DEGREES...BUT POTENTIAL FOR WARMER TEMPS IS THERE WITH 850 MB TEMPS
OF 16 C. LOW LEVEL MOISTURE/ELEVATED DEW PTS HOLDING IN THE LOWER
60S TONIGHT SHOULD SET THE STAGE FOR SOME FOG AS SKIES BECOME MAINLY
CLEAR WITH LIGHT/CALM WINDS IN PLACE.
LONG TERM...MONDAY THROUGH SATURDAY
SOUTHERN PLAINS UPPER RIDGE WILL UNDERGO STEADY DOWNSTREAM
AMPLIFICATION OVER THE NEXT 48 HOURS...IN RESPONSE TO SUBSTANTIAL
HEIGHT FALLS WORKING INTO THE WESTERN CONUS. THIS PROCESS WILL
EFFECTIVELY CENTER AN UPPER LEVEL ANTICYCLONE OVER SE MICHIGAN BY
MONDAY. A HIGH DEGREE OF STABILITY UNDER THE ATTENDANT MINIMUM IN
THETA-E AND AN ELEVATED MID LEVEL TEMPERATURE PROFILE WILL YIELD
PLENTY OF SUNSHINE...AND NO REAL OPPORTUNITY FOR CONVECTIVE
DEVELOPMENT. THE INCREASE IN THICKNESSES AND GENERALLY LIGHT
SOUTHWEST FLOW WILL PROVIDE A NOTED UPTICK IN TEMPERATURES RELATIVE
TO TODAY...WITH DAYTIME READINGS REACHING THE MID 80S.
UPPER RIDGING TO REMAIN THE PRIMARY GOVERNING FEATURE THROUGH THE
REMAINDER OF THE UPCOMING WORK WEEK. THIS WILL TRANSLATE INTO A
RELATIVELY BENIGN STRETCH OF WEATHER CONDITIONS...WITH ABOVE NORMAL
WARMTH AND LIMITED /IF ANY/ POTENTIAL FOR CONVECTION. THE RIDGE
AXIS MAY LOSE SOME DEFINITION BY MIDWEEK AS A WEAK HEIGHT FALL
CENTER DRIFTS THROUGH THE OHIO VALLEY...WITH A CORRESPONDING GRADUAL
INCREASE IN THETA-E DURING THIS TIME. PLAUSIBLE SCENARIO THAT WEAK
CVA WORKING THROUGH ALONG THE NORTH END OF THIS FEATURE PROVIDES A
LOCALIZED/BRIEF WINDOW FOR ASCENT...MEDIUM RANGE GUIDANCE STILL
CENTERING ON WEDNESDAY. LOW END POTENTIAL AT THIS STAGE GIVEN AN
OTHERWISE LACKLUSTER LOOKING FORCING/WIND FIELD.
MARINE...
BENIGN MARINE WEATHER WILL CONTINUE ACROSS THE GREAT LAKES REGION
THROUGH MUCH OF THE UPCOMING WEEK. A STRONG RIDGE OF UPPER LEVEL
HIGH PRESSURE WILL MAINTAIN LIGHT FLOW AND A GENERAL SOUTHWEST WIND
DIRECTION.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
UPDATE.......BT
AVIATION.....SF
SHORT TERM...SF
LONG TERM....MR
MARINE.......MR
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
404 PM CDT SUN AUG 30 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 400 PM CDT SUN AUG 30 2015
WATER VAPOR IMAGERY ALONG WITH RAP H5 HEIGHT ANALYSIS SHOWS UPPER
RIDGING BUILDING IN THIS AFTERNOON. A TROUGH EJECTING ACROSS THE
NRN ROCKIES HAS ALLOWED A BROAD AREA OF SFC LOW PRESSURE TO FORM
ACROSS ERN MT/NRN NODAK/SRN CANADA. IT IS THIS LOW THAT HAS
RESULTED IN AN INCREASING PRESSURE GRADIENT AND THE STRONGER SOUTH
WINDS WE HAVE SEEN TODAY.
IT IS THESE SOUTH WINDS THAT MAKE THE FORECAST FOR TONIGHT TRICKY.
NAM BUFR SOUNDINGS MONDAY MORNING LOOK LIKE CARBON COPIES OF THE MPX
SOUNDING THIS MORNING...WHICH OF COURSE WAS ASSOCIATED WITH ANOTHER
ROUND OF LOW STRATUS. STRATUS IS STILL HANGING TOUGH IN IOWA AND
WITH THE PATTERN TO OUR SOUTHEAST NOT MUCH DIFFERENT FROM WHAT WE
HAVE SEEN THE PAST COUPLE OF NIGHTS...EXPECT STRATUS TO EXPAND AGAIN
TONIGHT...THE QUESTION IS JUST HOW FAR NW DOES IT COME. ONE BIG
DIFFERENCE BETWEEN TODAY AND THE PAST COUPLE OF DAYS IS WE HAVE
STRONGER WINDS AND BETTER BOUNDARY LAYER MIXING TODAY. THE GRADIENT
AND ASSOCIATED WINDS WILL REMAIN IN PLACE THROUGH THE NIGHT...ADDING
A LAYER OF UNCERTAINTY TO THE SKY FORECAST. FOR NOW...DID A SOFT
PLAY FOR THE STRATUS...WITH 40/50% COVERAGE FROM SOUTH CENTRAL MN
INTO EAST CENTRAL MN AND WRN WI LATE TONIGHT/EARLY MONDAY MORNING
AND WILL LET FUTURE SHIFTS UP SKY COVER IF NEED BE WHEN THERE IS A
BETTER HANDLE ON WHERE IT IS GOING.
FOR MONDAY...THE PREVIOUSLY MENTIONED LOW WELL SEND A FRONT ACROSS
THE DAKOTAS...APPROACHING WEST CENTRAL MN BY THE AFTERNOON.
HOWEVER...WE ARE NOT ANTICIPATING ANY ACTIVITY ALONG THE FRONT THIS
FAR SOUTH...SO WE REMOVED WHAT SMALL POPS WERE MENTION MONDAY
AFTERNOON IN OUR NW. BESIDE NONE OF THE HI-RES...DETERMINISTIC...OR
ENSEMBLE MODELS SHOWING ANY PRECIP IN OUR AREA...FORECAST SOUNDINGS
AT AXN AND SURROUNDING SITES SHOW A STRONG WARM NOSE BETWEEN H8 AND
H7 THAT LOOKS TO KEEP A LID ON DEEP MOIST CONVECTION THIS FAR SOUTH.
IN ADDITION...THE WAVE AND ASSOCIATED HEIGHT FALLS DRIVING THIS
FRONT ARE GOING FROM MT TO HUDSON BAY...STAYING WELL NW OF THE
MPX AREA...SO FEEL CONFIDENT IN THE DRY FORECAST FOR MONDAY.
BESIDE DRY...ALL OF THE MODELS SHOW 925-850 TEMPS IN WRN MN DROPPING
A COUPLE OF DEGS C MONDAY AFTERNOON COMPARED TO WHAT WE ARE SEEING
TODAY...SO EXPECT HIGHS TO BE NO WARMER THAN WHAT WE ARE SEEING
TODAY AND LIKELY A COUPLE OF DEGREES COOLER IN WRN MN.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 400 PM CDT SUN AUG 30 2015
NO BIG CHANGES TO THE LONG TERM FORECAST AS THE PATTERN STILL
FAVORS RIDGING IN THE CENTRAL CONUS AND ABOVE NORMAL TEMPERATURES
LASTING INTO LABOR DAY WEEKEND.
THE LONGWAVE RIDGE AXIS WILL CONTINUE TO SHIFT EAST ON
TUESDAY...BUT THE BIGGEST RESERVOIR OF WARMTH WILL LINGER FROM THE
FOUR CORNERS UP THROUGH THE NORTHERN PLAINS. THE NAEFS
STANDARDIZED 850MB TEMPERATURE ANOMALIES ARE COMMONLY BETWEEN TWO
AND THREE SIGMA OVER THE NEXT WEEK IN THESE AREAS. AS THE 500MB
RIDGE AXIS SLIDES EAST ON TUESDAY THE LONGWAVE PATTERN LOSES SOME
OF ITS AMPLITUDE AND THE 850MB TEMPERATURE ADVECTION DECREASES
BEFORE REACHING THE FORECAST AREA. AS A RESULT...THE FORECAST AREA
WILL MAINTAIN MID 80S FOR HIGHS AS WE HEAD TOWARD MID WEEK...BUT
THE TEMPERATES WILL NOT APPROACH THE MID /AND EVEN UPPER/ 90S
THAT ARE CURRENTLY BEING OBSERVED IN THE DAKOTAS THIS AFTERNOON.
WESTERN MN IS ALREADY SEEING DEWPOINTS IN THE UPPER 60S AND
EASTERN MN AND WESTERN WI WILL SOON FOLLOW...THESE DEWPOINTS WILL
LINGER THROUGH THE WEEK AND THE DEWPOINT WILL MOST LIKELY HIT 70
DEGREES IN MANY LOCATIONS THIS WEEK. IN THE WED-THU TIME
FRAME...MUCH OF THE 12Z GUIDANCE HINTS AT THE CHANCE FOR RAIN WITH
MOISTURE TRANSPORT EMBEDDED IN THE LOW LEVEL SOUTHWEST FLOW. THE
FORCING ISNT EXTREMELY...BUT THERE IS ELEVATED INSTABILITY AND
THE CAP ISNT OVERLY STRONG EITHER WITH THE 12-14C AIR AT 700MB
REMAINING WEST OF THE AREA IN THE DAKOTAS. THEREFORE...WE
MAINTAINED THE SMALL POPS IN THE FORECAST...BUT ADMITTEDLY THERE
IS LOW CONFIDENCE ON TIMING/AMOUNTS AND EVEN IF THERE WILL BE MUCH
CONVECTIVE INITIATION LOCALLY.
THE PERSISTENT TROUGH OVER THE GULF OF ALASKA AND PACIFIC
NORTHWEST FINALLY LOOKS TO MAKE SOME EASTERN PROGRESS AS WE HEAD
TOWARD THE BACK HALF OF LABOR DAY WEEKEND. THE OPERATIONAL
GUIDANCE AND ENSEMBLE OUTPUT HAS SLIGHTLY SLOWED THE ARRIVAL OF
THE COLD FRONT...BUT AT THE VERY LEAST WE CAN SAY NEXT WEEKEND
LOOKS MORE UNSETTLED WITH A PATTERN SHIFT LOCALLY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1251 PM CDT SUN AUG 30 2015
STRONGER WINDS AND ASSOCIATED MECHANICAL MIXING HELPED CLEAN
STRATUS OUT MUCH FASTER THIS MORNING THAN WHAT WE SAW YESTERDAY.
REALLY...THE ONLY QUESTION THIS TAF PERIOD IS WHERE DOES THE
STRATUS RETURN TONIGHT. FORECAST SOUNDINGS FROM THE NAM LOOK LIKE
CARBON COPIES OF THIS MORNINGS SOUNDING HERE AT MPX...SO STRATUS
IS LOOKING LIKE A REAL POSSIBILITY FOR A THIRD NIGHT IN A ROW. ONE
BIG DIFFERENCE THOUGH BETWEEN TODAY AND YESTERDAY AS WE HAVE
STRONGER WINDS TODAY...WHICH MEANS BETTER BOUNDARY LAYER MIXING.
THIS IS WHAT ADDS UNCERTAINTY TO THE STRATUS FORECAST FOR
TONIGHT...IS THIS MIXING ENOUGH TO KEEP THE STRATUS FARTHER EAST
TONIGHT. FOR NOW...PLAYED UP THE STRATUS THREAT AT WIS TERMINALS
WHERE WINDS ARE WEAKEST TODAY...BUT IT IS CERTAINLY POSSIBLE TO
SEE STRATUS AS FAR WEST AS MSP/STC AGAIN TONIGHT.
KMSP...WILL BE VFR WITH SOUTH WINDS THE REST OF THE DAY. CURRENT
THINKING IS BETTER MIXING TODAY WILL MAKE IT MORE DIFFICULT TO GET
THE STRATUS GOING TONIGHT...BUT IF YOU WERE TO GO STRAIGHT OFF THE
NAM BUFR SOUNDING...MSP WILL SEE A REPEAT PERFORMANCE ON THE
STRATUS FOR A THIRD NIGHT IN A ROW. DECIDED TO GO THE SCT008 ROUTE
FOR NOW UNTIL THERE IS MORE CONFIDENCE ON WHERE STRATUS WILL END
UP TONIGHT.
/OUTLOOK FOR KMSP/
TUE-THU...VFR WINDS S 5-15 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...CLF
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS DULUTH MN
300 AM CDT SUN AUG 30 2015
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 257 AM CDT SUN AUG 30 2015
ONE THE SHORT TERM CONCERNS WILL BE THE AMOUNT OF SMOKE OVER THE
REGION TODAY AND MONDAY AND HOW THAT IMPACTS TEMPERATURES. A WEAK
COLD FRONT WILL ALSO MOVE INTO WESTERN MINNESOTA MONDAY AFTERNOON
BRINGING A THREAT FOR SHOWERS/STORMS TO OUR WESTERN ZONES.
AN UPPER RIDGE WILL MOVE OVER THE NORTHLAND TODAY AND PASS TO THE
EAST TONIGHT INTO MONDAY MORNING. STRATUS AND FOG WERE EXPANDING
THIS MORNING AND THE RAP/HRRR BOTH SHOW THIS TREND CONTINUING
OVERNIGHT...THEN THINNING BY 18Z. A LOOK AT YESTERDAYS VISIBLE
SATELLITE SHOWED PLENTY OF SMOKE OVER THE NORTHERN/CENTRAL PLAINS
INTO PORTIONS OF MINNESOTA. WE ARE CONCERNED THAT WE WILL SEE ENOUGH
SMOKE TO LIMIT SUNSHINE TODAY. WE TRIMMED HIGHS A BIT TODAY THINKING
THE SMOKE WILL BE PRESENT AND WE ALSO BEEFED UP CLOUD COVER SINCE
SMOKE WILL GIVE THE APPEARANCE OF HIGH CLOUDS. IF THE SMOKE IS
THINNER THAN EXPECTED...HIGHS WILL HAVE TO BE BUMPED BACK UP. WE
HAVE HIGHS TODAY FROM THE UPPER SEVENTIES TO MIDDLE EIGHTIES.
WE EXPECT CLOUDS TO INCREASE MONDAY AHEAD OF THE COLD FRONT...AND
SOME SMOKE WILL ONCE AGAIN BE PRESENT. WE HAVE HIGHS FROM 80 TO 85
FOR MOST AREAS. THERE WILL ALSO BE A SLIGHT CHANCE FOR SOME
AFTERNOON SHOWERS/STORMS OVER WESTERN AREAS OF THE NORTHLAND.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 257 AM CDT SUN AUG 30 2015
WARM AND HUMID THROUGH THE FIRST WEEK OF SEPTEMBER WITH CHANCES FOR
AN ISOLATED STORM MOST DAYS. LITTLE CHANGE TO THE PREVIOUS FORECAST
WITH ABOVE NORMAL CONFIDENCE IN THE OVERALL PATTERN. STORM CHANCES
EACH DAY ARE FAIRLY LOW...WITH THE BEST CHANCE FOR WIDESPREAD
SHOWERS AND STORMS LATE IN THE WEEK INTO THE WEEKEND AS A COLD FRONT
MOVES THROUGH FROM WEST TO EAST.
ON THE SYNOPTIC SCALE A LONGWAVE TROUGH WILL DEEPEN IN THE WEST
WHILE A WEAK RIDGE DEVELOPS OVER THE EAST...RESULTING IN
SOUTHWESTERLY FLOW ALOFT FOR THE UPPER MIDWEST. THIS WILL PLACE THE
REGION WITHIN THE STORM TRACK FOR A FEW WEAK MID-LEVEL IMPULSES
THROUGH THE WEEK. AT THE SURFACE A WARM FRONT WILL LIFT NORTH ACROSS
THE REGION ON WEDNESDAY INTO WEDNESDAY NIGHT...AND FOLLOWING THIS
STORM COVERAGE WILL LIKELY BE LIMITED THURS/FRI AFTERNOON UNTIL
FRIDAY NIGHT AND THROUGH THE WEEKEND AS A COLD FRONT MOVES THROUGH
FROM WEST TO EAST. AHEAD OF THE FRONT WINDS WILL BE BREEZY OUT OF
THE SOUTH...WITH A VERY HUMID WARM SECTOR IN PLACE AS DEW POINTS
RISE TO NEAR 70. STORMS THIS WEEKEND COULD HAVE THE POTENTIAL TO BE
STRONG TO SEVERE DUE TO FAIRLY STEEP MID-LEVEL LAPSE RATES WHICH
WILL AIDE IN INSTABILITY AND STRONGER MID/UPPER LEVEL WINDS LEADING
TO BETTER DEEP LAYER SHEAR. NOT CONFIDENT ENOUGH TO MENTION THIS IN
THE HWO JUST YET...BUT SHOULD THE RIGHT FACTORS ALIGN THIS IS A
POSSIBILITY.
HIGHS THROUGH THE WEEK AND INTO THE WEEKEND IN THE LOW TO MID
80S...EXCEPT FOR 70S BY LAKE SUPERIOR. LOWS IN THE MID 50S TO LOW
60S ON NIGHTS WHEN SKIES CLEAR...OTHERWISE IN THE MID TO UPPER 60S
DUE TO CLOUD COVER. WINDS PREDOMINATELY OUT OF THE SOUTH...BECOMING
GUSTY ON THURSDAY FRIDAY AND EVEN SATURDAY AHEAD OF THE COLD
FRONT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1232 AM CDT SUN AUG 30 2015
MOISTURE WILL RACE NORTH TO NORTHEAST ACROSS THE NORTHLAND
OVERNIGHT...AS A SOUTHERLY LLJ DEVELOPS ACROSS THE CENTRAL PORTION
OF THE COUNTRY. THE HRRR AND RAP CONTINUE TO INDICATE THAT LOW
CLOUDS AND FOG WILL HIT THE SOUTHEAST HALF OF THE FORECAST AREA THE
HARDEST...WITH IFR/LIFR CONDITIONS DEVELOPING OVERNIGHT. THERE IS A
BIT LOWER CONFIDENCE FOR KHIB AND KINL.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 81 64 84 64 / 0 10 10 30
INL 85 64 84 55 / 0 10 20 20
BRD 83 65 85 60 / 0 10 10 20
HYR 80 62 83 65 / 0 0 0 20
ASX 84 63 86 65 / 0 0 0 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...NONE.
&&
$$
SHORT TERM...MELDE
LONG TERM...JJM
AVIATION...DAP
AREA FORECAST DISCUSSION
NWS DULUTH MN
1233 AM CDT SUN AUG 30 2015
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 309 PM CDT SAT AUG 29 2015
HAVING A HARD TIME GETTING RID OF THE CLOUDS ACROSS THE FORECAST
AREA TODAY. LOOKS LIKE A UPPER LEVEL VORTICITY CENTER HAS BEEN
ROTATING THROUGH THE UPPER RIDGE..KEEPING CLOUDS OVER THE
NORTHLAND. BY SUNDAY MORNING WE SHOULD BE GRADUALLY CLEARING THE
CLOUDS AS THE UPPER RIDGING TAKES OVER. THERE WILL LIKELY B
MORNING CLOUDS...SIMILAR TO TODAY...BUT MIXING AND SUBSIDENCE SHOULD
HELP CLEAR OUT THE CLOUDS. VERY STRONG WARM AIR ADVECTION WILL
KEEP TEMPERATURES WARM OVERNIGHT...THEN VERY WARM TO HOT TOMORROW.
AND THE RETURN FLOW WILL ALSO BRING IN MORE HUMID AIR WITH
DEW POINTS IN THE MID TO UPPER 60S.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 309 PM CDT SAT AUG 29 2015
THE RIDGE PULLS OFF TO THE EAST AS SKIES WILL BE PARTLY CLOUDY
ACROSS THE REGION. A SURFACE TROUGH WILL DEVELOP UNDER A LONGWAVE
TROUGH SUNDAY NIGHT AND MOVE SLOWLY THROUGH NORTHERN/CENTRAL PLAINS
AND GREAT LAKES REGION ON MONDAY AND TUESDAY MORNING. ALSO...A
SOUTHERLY FLOW AHEAD OF THE TROUGH WILL PUSH WARMER AND MORE HUMID
AIR INTO THE FORECAST REGION. THERE WILL BE A BREAK IN THE PRECIP
CHANCES TUESDAY NIGHT AND WEDNESDAY MORNING AS A WEAK AREA OF HIGH
PRESSURE MOVES THROUGH THE REGION. A WARM FRONT WILL MOVE NORTH
INTO THE FORECAST AREA LATER WEDNESDAY KEEPING THE WARM AND HUMID
CONDITIONS ACROSS THE AREA. WEAK SHORTWAVES WILL PASS THROUGH THE
REGION WEDNESDAY NIGHT THROUGH FRIDAY MORNING KEEPING THE CHANCE OF
SCATTERED THUNDERSTORMS. A COLD FRONT WILL MOVE THROUGH THE
FORECAST AREA FRIDAY AFTERNOON THROUGH SATURDAY BRINGING WIDESPREAD
CONVECTION VERSUS SCATTERED EARLIER IN THE WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1232 AM CDT SUN AUG 30 2015
MOISTURE WILL RACE NORTH TO NORTHEAST ACROSS THE NORTHLAND
OVERNIGHT...AS A SOUTHERLY LLJ DEVELOPS ACROSS THE CENTRAL PORTION
OF THE COUNTRY. THE HRRR AND RAP CONTINUE TO INDICATE THAT LOW
CLOUDS AND FOG WILL HIT THE SOUTHEAST HALF OF THE FORECAST AREA THE
HARDEST...WITH IFR/LIFR CONDITIONS DEVELOPING OVERNIGHT. THERE IS A
BIT LOWER CONFIDENCE FOR KHIB AND KINL.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 63 84 64 82 / 0 0 30 20
INL 63 84 60 82 / 10 20 30 10
BRD 65 85 64 85 / 10 10 30 20
HYR 62 84 65 83 / 0 0 10 20
ASX 62 84 65 84 / 0 0 10 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...NONE.
&&
$$
SHORT TERM...CLC
LONG TERM...MRS
AVIATION...DAP
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
932 AM CDT SUN AUG 30 2015
.UPDATE...CURRENT FORECAST IS ON TRACK AND NO CHANGES ARE ANTICIPATED
AT THE MOMENT. UPPER LEVEL LOW OVER SOUTH AL BEGINNING TO LIFT OUT TO
THE NE...BUT STILL APPEARS CLOSE ENOUGH TO PROMOTE CONVECTIVE
DEVELOPMENT IN THE EAST THIS AFTERNOON WHERE MUCH DEEPER MOISTURE
REMAINS IN PLACE. THE HRRR AGREES WITH THIS SCENARIO AT IT DEVELOPS A
GOOD PEPPERING OF SHOWERS AND A FEW THUNDERSTORMS IN THAT PORTION OF
THE FORECAST AREA THIS AFTERNOON./26/
&&
.AVIATION...THE BRIEF MVFR CIGS THAT DEVELOPED OVER EAST MISSISSIPPI
THIS MORNING HAVE LIFTED AND VFR CONDS WERE BEING OBSERVED AT ALL
TAF SITES AT 14Z. VFR CONDS ARE EXPECTED TO PREVAIL THROUGH THIS
EVENING AREAWIDE. A POSSIBLE EXCEPTION WL BE MEI-GTR THIS AFTN/EVNG
DUE TO ISOLD TO SCT TSRA DEVELOPMENT. A BRIEF PERIOD 10Z-12Z MON OF
MVFR VSBYS WL BE PSBL ESPECIALLY IN THE EAST. /22/
&&
.PREV DISCUSSION... /ISSUED 412 AM CDT SUN AUG 30 2015/
DISCUSSION...
TODAY THROUGH MONDAY NIGHT...
WATER VAPOR IMAGERY REVEALS A WELL-DEFINED UPPER LOW MOVING SLOWLY
ACROSS THE CENTRAL GULF COAST THIS MORNING. CYCLONIC FLOW IS HELPING
TO TRANSPORT SUBSTANTIAL DEEP LAYER MOISTURE (PRECIPITABLE WATER >
1.5 INCHES) AROUND THE NORTHERN SIDE OF THE LOW AND THIS IS HELPING
TO INCREASE CONVECTIVE RAINFALL POTENTIAL OVER NORTHEAST
MISSISSIPPI...ESPECIALLY FOR LATER IN THE AFTERNOON DURING PEAK
HEATING. INSTABILITY IS POOR AND THUNDERSTORMS THAT DEVELOP ARE NOT
EXPECTED TO BE OVERLY INTENSE...BUT SLOW STORM MOTION COULD YIELD
LOCALLY HEAVY RAINFALL. FOR MOST OF THE AREA...DRY WEATHER WILL
CONTINUE.
MODELS FORECAST THE LOW TO MOVE NORTHEAST AND LIFT OUT AS AN
UPSTREAM WAVE DIGS SOUTHWARD ACROSS THE OZARK REGION. SUBSIDENCE IN
BETWEEN THESE FEATURES SHOULD MAKE FOR DRIER WEATHER MONDAY.
OTHERWISE...THE END OF AUGUST WILL BRING TYPICAL LATE SUMMER HEAT
AND HUMIDITY WITH AFTERNOON HEAT INDICES REACHING THE MID 90S. /EC/
TUESDAY THROUGH NEXT SUNDAY...
GLOBAL MODELS AND ENSEMBLES CONTINUE TO SHOW A PATTERN CHANGE OVER
THE CONUS FOR THE PERIOD WITH AN UPPER LEVEL TROUGH OVER WESTERN
CONUS AND STRONG SUBTROPICAL UPPER RIDGING OVER THE EASTERN CONUS.
OVER THE REGION A WEAK CUT OFF UPPER LOW WILL MEANDER ACROSS THE
REGION UNDER THE MEAN UPPER RIDGE. MEAN MOISTURE ACCORDING TO THE GFS
WILL GRADUALLY BUILD ACROSS THE REGION AS PWATS PUSH TO UP TO 2 PLUS
INCH RANGE BY FRIDAY...EXTENDING FOR THE REST OF THE PERIOD. THIS
WILL BRING LOW END CHANCES OF CONVECTION FOR THE WORK WEEK AS
MIDLEVEL CAPPING WILL INHIBIT DEVELOPMENT WITHOUT ANY FOCUSED LIFT.
AS WE PUSH INTO FRIDAY THROUGH THE WEEKEND CHANCES OF CONVECTION
SLOWLY INCREASE WE DEVELOP DEEPER MOISTURE ACCORDING TO THE GFS OVER
THE REGION. GFS MODEL CROSS SECTIONS SHOWS BETTER VERTICAL LIFT
DURING THE TIME. THE EURO MODEL WAS NOT AS DEEP WITH THE MOISTURE
OVER THE WEEKEND. IT SHOWED SOME MID TO UPPER LEVEL DRYING. SO OPTED
TO KEEP LOWER END POPS FOR THE WEEKEND. A NORTHERN STREAM SHORT WAVE
WILL HELP TO FLATTERN MEAN SUBTROPICAL RIDGE OVER MOST OF THE CONUS
BY THE END OF THE PERIOD.
DAILY HIGHS WILL AVERAGE IN THE 91-95 RANGE WITH LOWS IN THE LOWER
70S AS MORE HUMID CONDITIONS WILL COME BACK TO THE REGION. WITH THIS
IN MIND MADE SMALL ADJUSTMENTS TO CURRENT FORECAST BASED ON NEW
MODEL GUIDANCE./17/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 92 68 92 69 / 12 7 7 4
MERIDIAN 88 65 91 67 / 29 7 5 5
VICKSBURG 94 66 94 67 / 4 7 6 5
HATTIESBURG 93 68 94 70 / 9 6 6 3
NATCHEZ 90 68 90 69 / 4 7 10 5
GREENVILLE 93 69 93 70 / 8 9 5 5
GREENWOOD 92 67 92 68 / 20 8 5 6
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
26/22/EC/17
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
920 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 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 537 PM CDT MON AUG 31 2015
UPPER LEVEL LOW/SHEAR AXIS WILL REMAIN IN THE REGION FOR ANOTHER
24 HOURS. IT SEEMS THE BEST AREA FOR SHOWER/THUNDERSTORM
DEVELPMENT WILL BE ALONG MOISTURE CONVERGENCE REGIONS THAT FORM ON
THE WEST SIDE OF THE UPPER LOW WHICH WILL BE OVER INDIANA BY 12Z
TUESDAY. THIS SHOULD KEEP THE DEVELOPEMENT EAST OF THE TERMINALS
OVERNIGHT. GUIDANCE KEEPS A 5-6 KNOT WIND OVERNIGHT AND THIS MAY
KEEP ANY FOG AT UIN AND COU FROM BEING VERY THICK. SUS AND CPS MAY
CALM OUT, SO WILL HIT FOG THERE A BIT HARDER.
SPECIFICS FOR KSTL: DEPENDING ON HOW THE RADAR LOOKS, MAY KEEP A
VCTY IN FOR AN HOUR OR MAY GO DRY. OTHERWISE PERSISTANCE RULES THE
FORECAST EXCEPT FOR A SLIGHTLY STRONGER SOUTHERLY WIND OVERNIGHT.
HIGH PRESSURE TO THE SOUTHEAST WILL CONTROL THE WEATHER, GENERALLY
DRY AND VFR.
JPK
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BILLINGS MT
311 PM MDT SUN AUG 30 2015
.SHORT TERM...VALID FOR MON AND TUE...
A SEASONABLY STRONG COLD FRONT WILL CROSS THE REGION TONIGHT AND
LEAD INTO A PERIOD OF QUIET WEATHER MONDAY AND TUESDAY.
TONIGHT...THE 12 UTC MODELS AND MORE CONTEMPORARY HRRR MODEL RUNS
ARE IN GENERAL AGREEMENT IN SHOWING THE COLD FRONT MOVING THROUGH
THE LIVINGSTON AREA BETWEEN 6 PM AND 9 PM MDT...BILLINGS BETWEEN 7
PM AND 11 MDT...SHERIDAN BETWEEN 11 PM AND 3 AM MDT...AND MILES
CITY AND BAKER AFTER MIDNIGHT. WE EXPECT A SHIFT TO WEST-NORTHWEST
WINDS BEHIND THE FRONT WITH GUSTS TO 45 MPH BASED ON THE DEGREE OF
LOW- AND MID-LEVEL COLD AIR ADVECTION AND THERMAL GRADIENT IN THE
FRONTAL ZONE. THAT/S SUPPORTED BY MOS STATISTICAL OUTPUT /THE MAV
AND MET/ AS WELL. FORECAST SOUNDINGS DO SUGGEST THE BOUNDARY LAYER
MAY BE A BIT TOO DECOUPLED FOR FULL MOMENTUM TRANSFER OF THE 40 KT
WINDS THAT ARE SIMULATED WITHIN 3000 FT AGL OF THE GROUND...BUT WE
BELIEVE THE COLD AIR ADVECTION WILL OVERCOME THAT TENDENCY. A RED
FLAG WARNING CONTINUES THROUGH THE EVENING TO CONVEY THE RISK THIS
COLD FRONTAL PASSAGE WILL PRESENT FOLLOWING LATE-AFTERNOON MIX-OUT
OF GUSTY SOUTHWEST WINDS AND DRYING IN SOUTH CENTRAL MT.
WHERE PRECIPITATION IS CONCERNED...ISOLATED SHOWERS AND STORMS ARE
POSSIBLE WITH THE SHORTWAVE TROUGH PASSAGE DRIVING THE COLD FRONT
EASTWARD...MAINLY THIS EVENING. STRONG MID-LEVEL WINDS SUGGEST A
STRONG STORM IS POSSIBLE...BUT WE FEEL THAT RISK WILL GENERALLY BE
MITIGATED BY A LACK OF STRONGER INSTABILITY.
MONDAY...THE POST-FRONTAL AIR MASS WILL BE COOLER...DRIER...AND
STABLE. HIGHS WILL BE NEAR 80 F WITH AFTERNOON HUMIDITIES AROUND
20 PERCENT PER THE 12 UTC MULTI-MODEL CONSENSUS WE USED TO DERIVE
THE OFFICIAL FORECAST...BUT WIND/S WILL NOT BE ANYTHING TO WRITE
HOME ABOUT.
TUESDAY...DEEPER MIXING TO 700 MB OR MORE AND WARMING TEMPERATURES
ALOFT WITH SOUTHWEST FLOW WILL PROMOTE A WARM-UP INTO THE UPPER
80S AND LOWER 90S F. ATMOSPHERIC MOISTURE CONTENT WON/T CHANGE
TOO MUCH AND THE RESULT WILL BE EVEN LOWER HUMIDITIES WELL DOWN
INTO THE TEENS...THOUGH WINDS AREN/T EXPECTED TO BE STRONG ENOUGH
FOR ANY RED-FLAG-TYPE CONDITIONS. SCHULTZ
.LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN...
UPPER TROUGH OVER THE PACIFIC NORTHWEST WILL MOVE INLAND ON
WEDNESDAY AND THIS SETS UP DEEP SOUTHWEST FLOW OVER SOUTHERN
MONTANA AND NORTHERN WYOMING. HIGHS WILL APPROACH 90 DEGREES ON
WEDNESDAY AHEAD OF COLD FRONT. THIS FRONT WILL MOVE THROUGH
WEDNESDAY NIGHT AND BRING COOLER WEATHER FOR THE END OF THE WEEK.
IN FACT...THIS WILL MARK A DRAMATIC PATTERN CHANGE AS THE WESTERN
TROUGH SWINGS OVER THE NORTHERN ROCKIES THIS WEEKEND. THIS WILL
END THE WARM AND DRY REGIME AND PROVIDE COOLER TEMPERATURES AND A
CHANCE OF PRECIPITATION. SOME OF THE MOUNTAIN TOPS COULD EVEN SEE
A LITTLE SNOW SATURDAY AND SUNDAY...ALTHOUGH THE STRONGER FORCING
AND MOST LIKELY PRECIPITATION PLACEMENT...WOULD BE OVER NORTHERN
MONTANA. TWH
&&
.AVIATION...
STRONG SOUTHWEST WINDS WILL CONTINUE AT KLVM THIS AFTERNOON WITH
SOME GUSTS TO 35KTS. WIDELY SCATTERED SHOWERS AND THUNDERSTORMS
WILL DEVELOP THROUGH THIS EVENING AS A COLD FRONT APPROACHES. SOME
OF THE STORMS NORTHWEST OF BILLINGS COULD BE STRONG WITH WIND
GUSTS TO 45KTS. A COLD FRONT WILL MOVE THROUGH CENTRAL LOCATIONS
FROM KBIL TO KLVM FROM 01-03Z...KSHR 02-04Z AND KMLS AND KBHK
04-06Z. NORTHWEST WINDS WILL GUST TO 35KTS BEHIND THE FRONT. TWH
&&
.PRELIMINARY POINT TEMP/POPS...
MON TUE WED THU FRI SAT SUN
-----------------------------------------------------------
BIL 054/082 054/089 059/090 055/075 048/069 047/070 045/071
20/U 00/U 01/U 11/B 23/T 33/T 22/T
LVM 045/080 046/086 051/085 048/072 041/067 038/069 039/073
20/K 00/K 01/B 23/T 44/T 44/T 32/T
HDN 054/083 053/092 057/094 056/080 048/075 048/072 046/073
20/U 00/U 11/U 11/B 22/T 22/T 22/T
MLS 057/082 055/092 059/097 059/081 051/077 049/073 047/072
30/U 00/U 00/U 11/B 22/T 22/T 22/T
4BQ 056/080 055/092 059/096 058/082 053/079 051/071 049/070
30/U 00/U 00/U 01/U 12/T 22/T 22/T
BHK 055/079 054/091 057/095 058/081 051/080 049/073 046/070
30/U 00/U 10/U 11/U 12/T 22/T 22/T
SHR 050/083 049/091 054/092 053/082 046/076 044/070 042/071
20/U 00/U 10/U 01/B 12/T 22/T 22/T
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...RED FLAG WARNING IN EFFECT UNTIL MIDNIGHT MDT TONIGHT FOR
ZONES 28-29-34-35-39>42-56-63>68.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
954 AM PDT SUN AUG 30 2015
.SYNOPSIS...A BROAD LOW PRESSURE TROUGH MOVING INTO THE GREAT BASIN
AND MOJAVE DESERT REGION WILL BRING DRY SOUTHWEST FLOW WITH COOLER
AND BREEZY CONDITIONS THROUGH THE COMING WEEK AND INTO THE LABOR DAY
WEEKEND. SLIGHT CHANCES FOR THUNDERSTORMS WILL REMAIN IN EASTERN
MOHAVE COUNTY WITH ACTIVITY DECREASING THROUGH TUESDAY.
&&
.UPDATE...A BAND OF MID AND HIGH CLOUDS EXTENDING FROM SOUTHERN
CALIFORNIA ACROSS SOUTHERN NEVADA INTO UTAH WAS SHOWING SIGNS OF
DECREASING AND LIFTING TO THE NORTHEAST. THE LATEST HIGH LEVEL RH
FORECASTS INDICATE THIS TREND WHICH ALLOW MORE SUNSHINE DURING THE
AFTERNOON. THE 12Z LAS VEGAS SOUNDING REVEALED 2-3 DEGREES C OF
COOLING BETWEEN THE SURFACE AND 700 MB AND HIGH TEMPS THIS AFTERNOON
WILL REFLECT THE BEGINNING OF THIS COOLING TREND. OVERALL...THE
FORECAST TRENDS LOOK OKAY AND NO IMMEDIATE CHANGES NEEDED. -ADAIR-
&&
.PREV DISCUSSION...
200 AM PDT SUN AUG 30 2015
.SHORT TERM...TONIGHT THROUGH TUESDAY.
A SOUTHWESTERLY FLOW HAS TAKEN HOLD OF THE REGION IN RESPONSE TO
TROUGHING ACROSS THE PACIFIC NORTHWEST AND HIGH PRESSURE SHUNTED
SOUTHWARD INTO NORTHERN MEXICO. THIS HAS RESULTED IN THE MOIST
MONSOONAL FLOW BEING SUBDUED AND PUSHED MORE INTO ARIZONA LEAVING
MOST OF OUR FORECAST AREA HIGH AND DRY FOR THE FORESEEABLE FUTURE.
ONLY CAVEAT TO THAT WILL BE ACROSS EASTERN MOHAVE COUNTY THE NEXT
COUPLE AFTERNOONS WHERE SOME MARGINAL INSTABILITY WILL REMAIN IN
PLACE TO SUPPORT ISOLATED TO SCATTERED THUNDERSTORMS MAINLY THE
HIGHER TERRAIN. EARLY MORNING RUNS OF THE HRRR SUPPORT THIS AGAIN
FOR THIS AFTERNOON...PARTICULARLY NORTH OF THE I-40 CORRIDOR IN
EASTERN MOHAVE COUNTY...AND HAVE MAINTAINED POPS FOR THOSE AREAS
THIS AFTERNOON.
ELSEWHERE...SOME PERIODS OF HIGH CLOUDS CAN BE EXPECTED BUT NOTHING
OVERLY SUBSTANTIAL. HIGH TEMPERATURES WILL CREEP DOWNWARD THROUGH
TUESDAY BUT SHOULD REMAIN SLIGHTLY ABOVE NORMAL THROUGH
MONDAY...BEFORE RETURNING TO NEAR NORMAL ON TUESDAY.
.LONG TERM...WEDNESDAY THROUGH SUNDAY.
NUMEROUS SHORTWAVES WILL MOVE THROUGH A LONGWAVE TROUGH WHICH WILL
REMAIN OVER THE PAC NW/NRN ROCKIES DURING MUCH OF THE PERIOD. THIS
WILL KEEP THE SOUTHERN GREAT BASIN/MOJAVE DESERT UNDER A SOUTHWEST
FLOW. LOOK FOR BREEZY TO LOCALLY WINDY AFTERNOON/EVENING HOURS WITH
SLIGHTLY BELOW NORMAL TEMPERATURES.
SOMETHING TO MONITOR WILL BE THE POTENTIAL DEVELOPMENT OF A TROPICAL
SYSTEM IN THE EASTERN PACIFIC. BOTH THE GFS/ECMWF DEVELOP A SYSTEM
WELL SOUTHWEST OF CABO SAN LUCAS WEDNESDAY. THE FEATURE MOVES NORTH
BUT LOOKS TO GET SHEARED APART WEST OF THE BAJA PENINSULA FRIDAY
WITH REMNANT MID LEVEL ENERGY GETTING CAUGHT IN THE SOUTHWEST FLOW
AND MOVING OVER ARIZONA SATURDAY. THE ASSOCIATED MOISTURE BEARS
WATCHING AS SOME OF IT MAY GET PULLED NORTHWARD UP THE COLORADO
RIVER AND INTO WESTERN ARIZONA SATURDAY NIGHT OR SUNDAY.
&&
.AVIATION...FOR MCCARRAN...FAIR WEATHER EXPECTED TODAY WITH PERIODS
OF PASSING HIGH CLOUDS. SOUTHWESTERLY WINDS EXPECTED MOST OF THE DAY
WITH SPEEDS OF 12-20 KTS WITH GUSTS TO 25 KTS. WHILE
UNLIKELY...THERE IS A SMALL POSSIBILITY OF A PERIOD OF SOUTHEAST
WINDS BETWEEN 15Z-18Z. WIND GUSTS WILL DECREASE AFTER SUNSET.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...FAIR WEATHER EXPECTED WITH ONLY SLIGHT CHANCES FOR
THUNDERSTORMS IN FAR EASTERN MOHAVE COUNTY. ELSEWHERE..JUST PASSING
HIGH CLOUDS EXPECTED WITH AREAS OF SMOKE IN THE OWENS VALLEY AND
NEAR KBIH. BREEZY SOUTHWEST WINDS OF 15-20KT WITH GUSTS TO 30KTS
EXPECTED IN THE AFTERNOON.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTER ACTIVATION WILL NOT BE
NECESSARY. HOWEVER...SPOTTERS ARE ENCOURAGED TO REPORT ANY
SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
SHORT TERM/AVIATION...OUTLER
LONG TERM...PIERCE
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
200 AM PDT SUN AUG 30 2015
.SYNOPSIS...A BROAD LOW PRESSURE TROUGH MOVING INTO THE GREAT BASIN
AND MOJAVE DESERT REGION WILL BRING DRY SOUTHWEST FLOW WITH COOLER
AND BREEZY CONDITIONS THROUGH THE COMING WEEK AND INTO THE LABOR DAY
WEEKEND. SLIGHT CHANCES FOR THUNDERSTORMS WILL REMAIN IN EASTERN
MOHAVE COUNTY WITH ACTIVITY DECREASING THROUGH TUESDAY.
&&
.SHORT TERM...TONIGHT THROUGH TUESDAY.
A SOUTHWESTERLY FLOW HAS TAKEN HOLD OF THE REGION IN RESPONSE TO
TROUGHING ACROSS THE PACIFIC NORTHWEST AND HIGH PRESSURE SHUNTED
SOUTHWARD INTO NORTHERN MEXICO. THIS HAS RESULTED IN THE MOIST
MONSOONAL FLOW BEING SUBDUED AND PUSHED MORE INTO ARIZONA LEAVING
MOST OF OUR FORECAST AREA HIGH AND DRY FOR THE FORESEEABLE FUTURE.
ONLY CAVEAT TO THAT WILL BE ACROSS EASTERN MOHAVE COUNTY THE NEXT
COUPLE AFTERNOONS WHERE SOME MARGINAL INSTABILITY WILL REMAIN IN
PLACE TO SUPPORT ISOLATED TO SCATTERED THUNDERSTORMS MAINLY THE
HIGHER TERRAIN. EARLY MORNING RUNS OF THE HRRR SUPPORT THIS AGAIN
FOR THIS AFTERNOON...PARTICULARLY NORTH OF THE I-40 CORRIDOR IN
EASTERN MOHAVE COUNTY...AND HAVE MAINTAINED POPS FOR THOSE AREAS
THIS AFTERNOON.
ELSEWHERE...SOME PERIODS OF HIGH CLOUDS CAN BE EXPECTED BUT NOTHING
OVERLY SUBSTANCIAL. HIGH TEMPERATURES WILL CREEP DOWNWARD THROUGH
TUESDAY BUT SHOULD REMAIN SLIGHTLY ABOVE NORMAL THROUGH
MONDAY...BEFORE RETURNING TO NEAR NORMAL ON TUESDAY.
.LONG TERM...WEDNESDAY THROUGH SUNDAY.
NUMEROUS SHORTWAVES WILL MOVE THROUGH A LONGWAVE TROUGH WHICH WILL
REMAIN OVER THE PAC NW/NRN ROCKIES DURING MUCH OF THE PERIOD. THIS
WILL KEEP THE SOUTHERN GREAT BASIN/MOJAVE DESERT UNDER A SOUTHWEST
FLOW. LOOK FOR BREEZY TO LOCALLY WINDY AFTERNOON/EVENING HOURS WITH
SLIGHTLY BELOW NORMAL TEMPERATURES.
SOMETHING TO MONITOR WILL BE THE POTENTIAL DEVELOPMENT OF A TROPICAL
SYSTEM IN THE EASTERN PACIFIC. BOTH THE GFS/ECMWF DEVELOP A SYSTEM
WELL SOUTHWEST OF CABO SAN LUCAS WEDNESDAY. THE FEATURE MOVES NORTH
BUT LOOKS TO GET SHEARED APART WEST OF THE BAJA PENINSULA FRIDAY
WITH REMNANT MID LEVEL ENERGY GETTING CAUGHT IN THE SOUTHWEST FLOW
AND MOVING OVER ARIZONA SATURDAY. THE ASSOCIATED MOISTURE BEARS
WATCHING AS SOME OF IT MAY GET PULLED NORTHWARD UP THE COLORADO
RIVER AND INTO WESTERN ARIZONA SATURDAY NIGHT OR SUNDAY.
&&
.AVIATION...FOR MCCARRAN...FAIR WEATHER EXPECTED TODAY WITH PERIODS
OF PASSING HIGH CLOUDS. SOUTHWESTERLY WINDS EXPECTED MOST OF THE DAY
WITH SPEEDS OF 12-20 KTS WITH GUSTS TO 25 KTS. WHILE
UNLIKELY...THERE IS A SMALL POSSIBILITY OF A PERIOD OF SOUTHEAST
WINDS BETWEEN 15Z-18Z. WIND GUSTS WILL DECREASE AFTER SUNSET.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...FAIR WEATHER EXPECTED WITH ONLY SLIGHT CHANCES FOR
THUNDERSTORMS IN FAR EASTERN MOHAVE COUNTY. ELSEWHERE..JUST PASSING
HIGH CLOUDS EXPECTED WITH AREAS OF SMOKE IN THE OWENS VALLEY AND
NEAR KBIH. BREEZY SOUTHWEST WINDS OF 15-20KT WITH GUSTS TO 30KTS
EXPECTED IN THE AFTERNOON.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTER ACTIVATION WILL NOT BE
NECESSARY. HOWEVER...SPOTTERS ARE ENCOURAGED TO REPORT ANY
SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
SHORT TERM/AVIATION...OUTLER
LONG TERM...PIERCE
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1046 PM EDT MON AUG 31 2015
.SYNOPSIS...
LOW PRESSURE ALONG THE NORTH CAROLINA COAST SHOULD MOVE NORTHEAST
AND AWAY FROM THE AREA TONIGHT. A LINGERING TROUGH WILL REMAIN
ACROSS THE EASTERN CAROLINAS TUESDAY. HIGH PRESSURE WILL BUILD
INTO THE AREA FROM THE NORTH FRIDAY NIGHT AND THROUGH THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
AS OF 1030 PM MONDAY...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 TUESDAY 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 /00Z TUESDAY THROUGH SATURDAY/...
AS OF 00Z...A MIXTURE OF VFR/MVFR/IFR ON TAP TONIGHT THROUGH THE
EARLY MORNING HOURS ON TUESDAY 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.
SHOWERS CONTINUE TO MOVE THROUGH PORTIONS OF THE FORECAST AREA THIS
EVENING...CURRENTLY AFFECTING KILM...AS SEEN BY LATEST RADAR
IMAGERY. EXPECT THIS ACTIVITY TO TAPER OFF OVER THE NEXT COUPLE OF
HOURS AND FOR SKIES TO GRADUALLY CLEAR...AS ALREADY SEEN INLAND ON
SATELLITE IMAGERY. OTHER THAN INTERMITTENTLY LINGERING FEW/SCT MID
CLOUDS INTO THE OVERNIGHT HOURS...MAINLY CLEAR SKIES AND LIGHT WINDS
WILL NOT LAST LONG AS SOME GUIDANCE SUGGESTS MOISTURE RETURN
OVERNIGHT. AS A RESULT...ANTICIPATE STRATUS AND FOG DEVELOPMENT
OVERNIGHT 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.
EXTENDED OUTLOOK...PREDOMINATELY VFR WITH BRIEF MORNING FOG AND
ISOLATED/SCATTERED AFTERNOON CONVECTION.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 PM MONDAY...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...
NEAR TERM...TRA
SHORT TERM...RJD
LONG TERM...MBB
AVIATION...SRP
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1020 PM EDT MON AUG 31 2015
.SYNOPSIS...AN UPPER LEVEL LOW WILL MOVE NORTHEASTWARD AWAY FROM THE
AREA THROUGH THE REST OF TODAY. OTHERWISE... A WEAK SURFACE TROUGH
WILL HOLD OVER EASTERN NORTH CAROLINA... WHILE HIGH PRESSURE
CENTERED OVER KENTUCKY EXTENDS OVER WESTERN NORTH CAROLINA.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM MONDAY...
THE SHIELD OF TROPICAL RAIN HAS SHIFTED EAST OF THE FORECAST AREA...
WHILE THE MID LEVEL LOW HAS MOVED WELL TO OUR NE. WHILE A FEW
SHALLOW SHOWERS REMAIN POSSIBLE... THE THREAT OF ADDITIONAL
SIGNIFICANT RAINFALL WILL HOLD JUST TO OUR EAST FOR THE REMAINDER OF
THE DAY. LATEST SURFACE ANALYSIS SHOWS LOW PRESSURE JUST OFF THE CHS
COAST... AND THIS WILL TRACK TO THE NNE ALONG THE SURFACE TROUGH
OVER ERN NC... ACCOMPANIED BY A MID LEVEL WAVE NOTED ON WATER VAPOR
IMAGERY JUST UPSHEAR. EXTRAPOLATION SUGGESTS THAT THE RAIN SHIELD IS
LIKELY TO HOLD JUST TO OUR EAST OR PERHAPS BRUSH ALONG THE FAR ERN
COASTAL PLAIN AS THE LOW TRACKS OVER ERN NC... A SCENARIO NEARLY IN
LINE WITH THE LATEST HRRR RUNS. WILL RETAIN A LOW CHANCE POP OVER
THE CENTRAL/ERN FORECAST AREA INTO EARLY EVENING... THEN EXPECT DRY
WEATHER OVERNIGHT AS THE DRIER AIR NOTED ON WATER VAPOR IMAGERY TO
OUR SW CONTINUES TO OVERSPREAD ALL OF CENTRAL NC. IT`S A DIFFERENT
STORY NEAR THE GROUND HOWEVER... AS HIGHER DEWPOINTS AND LOW LEVEL
MOISTURE HOLDING OVER THE ERN HALF OF NC ALONG WITH A WET GROUND AND
LIGHT OR CALM SURFACE WINDS LEAD TO FAVORABLE CONDITIONS FOR
FOG/STRATUS DEVELOPMENT... PARTICULARLY FROM THE TRIANGLE AND FAY TO
THE EAST/NORTHEAST. EXPECT ABOVE-NORMAL LOWS FROM 67-72. -GIH
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 300 PM MONDAY...
A WEAK SURFACE PATTERN FEATURING A BROAD TROUGH OVER ERN NC AND KY-
CENTERED RIDGE EXTENDING INTO WRN NC WILL REMAIN IN PLACE... WHILE
ALOFT... HEIGHTS RISE OVER NC IN THE WAKE OF THE EXITING WAVE... AND
AHEAD OF THE LOW NOW OVER CENTRAL INDIANA. FORECAST SOUNDINGS DEPICT
FAIRLY DRY AND STABLE AIR THROUGH THE MID AND UPPER LEVELS...
ALTHOUGH A MODERATE AMOUNT OF LINGERING LOW LEVEL MOISTURE
ESPECIALLY IN THE EAST SHOULD RESULT IN SCATTERED TO BROKEN STRATOCU
PARTICULARLY FROM LATE MORNING THROUGH EARLY EVENING. ONCE THE
MORNING FOG LIFTS AND MIXES OVER THE NRN AND ERN CWA... EXPECT
GENERALLY PARTLY CLOUDY SKIES. WILL KEEP A SLIGHT CHANCE OF AN
AFTERNOON SHOWER OR STORM IN THE FAR ERN CWA... WHERE LOW LEVEL
MOISTURE WILL BE BETTER AND WHERE MUCAPE IS FORECAST TO APPROACH OR
EXCEED 1000 J/KG... BUT THE LACK OF A FOCUS FOR ASCENT AND LIMITED
MOISTURE ALOFT SHOULD KEEP COVERAGE LOW. HIGHS 88-92 WITH
THICKNESSES A BIT ABOVE NORMAL. FAIR TO PARTLY CLOUDY TUE NIGHT WITH
LOWS 69-72. -GIH
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
AS OF 300 PM MONDAY...
A FAIRLY LOW CONFIDENCE FORECAST FOR THE EXTENT OF THE LONG TERM AS
THERE IS VERY LITTLE FORCING IN THE UPPER LEVELS WITH NO REAL
DISCERNIBLE JETS OR STRONG SHORTWAVES IN THE VICINITY OF CENTRAL NC.
THEREFORE MUCH OF THE LONG TERM FORECAST WILL BE BUILT AROUND LOWER
LEVEL FEATURES.
WEDNESDAY SHOULD BE FAIRLY UNEVENTFUL WITH VERY WEAK HIGH PRESSURE
OVER THE WESTERN ATLANTIC AND A SURFACE LOW MOVING THROUGH EASTERN
CANADA. THE SURFACE FRONT ASSOCIATED WITH THIS FEATURE WILL BE VERY
WEAK WITH NOT MUCH OF AN AIRMASS CHANCE BUT MAYBE JUST ENOUGH
FORCING FOR A SLIGHT UPTICK IN CONVECTION ON THURSDAY
AFTERNOON/EVENING WITH SHOWERS LINGERING INTO THE EARLY MORNING
HOURS ON FRIDAY.
DURING THE DAY ON FRIDAY HIGH PRESSURE WILL BEGIN TO STRENGTHEN OVER
NEW ENGLAND AND RETROGRADE SOUTHWESTWARD INTO THE MID ATLANTIC
STATES. THIS WILL HELP PUSH A BACK DOOR COLD FRONT THROUGH THE AREA
LATER ON FRIDAY AND GIVING US A COOLER AIRMASS FOR THE WEEKEND AND
INTO MONDAY.
TEMPERATURES WILL MAINLY RUN IN THE UPPER 80S/LOW 90S EARLY IN THE
PERIOD AND THEN DROP INTO THE LOW TO MID 80S FOR THE WEEKEND AND
INTO EARLY NEXT WEEK. LOWS GENERALLY IN THE MID TO UPPER 60S. PRECIP
CHANCES WILL MAINLY BE SLIGHT CHANCE THROUGH THE WORK WEEK WITH
CHANCE POPS FOR THE WEEKEND. -RE
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 900 PM MONDAY...
24-HR TAF PERIOD:
INT/GSO: VFR CONDITIONS WILL PREVAIL THE MAJORITY OF THE NIGHT AT
THE INT/GSO TERMINALS...ASIDE FROM A POTENTIAL FOR A SHORT PERIOD OF
IFR CEILINGS DURING THE PRE-DAWN HOURS (09-13Z). OTHERWISE...VFR
CONDITIONS AND LIGHT/VARIABLE WINDS WILL PREVAIL.
RDU/FAY/RWI: DETERIORATING CONDITIONS ARE EXPECTED OVERNIGHT AT
EASTERN TERMINALS WHERE SKIES HAVE CLEARED IN THE PRESENCE OF CALM
WINDS...MOIST AIRMASS...AND MOIST GROUND CONDITIONS FROM RECENT
RAINFALL. EXPECT LIFR CONDITIONS ATTENDANT EITHER LOW CEILINGS OR
LOW VISBYS IN DENSE DOG...PARTICULARLY AFTER MIDNIGHT...WITH THE
WORST CONDITIONS IN THE 08-13Z TIME FRAME. CONDITIONS WILL IMPROVE
BETWEEN 12-15Z...WITH VFR CONDITIONS PERSISTING THE REMAINDER OF THE
TAF PERIOD ASIDE FROM A SMALL POTENTIAL FOR AN ISOLD SHOWER AT THE
FAY/RWI TERMINALS DURING THE MID/LATE AFTERNOON. NOTE: THE RDU
TERMINAL APPEARS TO BE IN THE MOST FAVORABLE LOCATION FOR DENSE FOG
TO DEVELOP AND PERSIST FOR SEVERAL HOURS LATE TONIGHT AND EARLY TUE
MORNING. -VINCENT
LOOKING BEYOND 00Z WED: VFR CONDITIONS ARE EXPECTED TUE AFTERNOON
INTO TUE NIGHT...BUT MVFR TO IFR FOG IS POSSIBLE LATE TUE NIGHT INTO
WED MORNING. VFR CONDITIONS SHOULD THEN PREVAIL THROUGH SAT.
SCATTERED SUB-VFR SHOWERS/STORMS ARE POSSIBLE EACH AFTERNOON/EVENING
WED THROUGH SAT...ALTHOUGH FORECAST CONFIDENCE IS QUITE LOW WITH
DETAILS OF POSSIBLE TIMING OR COVERAGE. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...KS
NEAR TERM...HARTFIELD
SHORT TERM...HARTFIELD
LONG TERM...ELLIS
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS NORMAN OK
1045 PM CDT MON AUG 31 2015
.AVIATION...
6Z TAFS...A FEW HIGH CLOUDS FROM CONVECTION OVER THE HIGH
PLAINS...MAY SPREAD OVER WESTERN OKLAHOMA TONIGHT. OTHERWISE...
VFR CONDITIONS AND A SOUTH WIND CAN BE EXPECTED.
&&
.PREV DISCUSSION... /ISSUED 656 PM CDT MON AUG 31 2015/
AVIATION...
VFR CONDITIONS AND A SOUTH WIND WILL PREVAIL THROUGH 00Z
WEDNESDAY.
PREV DISCUSSION... /ISSUED 326 PM CDT MON AUG 31 2015/
DISCUSSION...
A WEAK UPPER LOW CONTINUES TO SPIN ACROSS SOUTHEAST OKLAHOMA.
ALTHOUGH LATEST RAP & HRRR RUNS KEEP IT INACTIVE THERE, WATER
VAPOR IMAGERY CONTINUES TO SHOW A SLIGHT MIDLEVEL CIRCULATION,
ENOUGH TO MAINTAIN LOW TSRA POPS THERE UNTIL THIS EVENING.
OTHERWISE, AN UPPER RIDGE IS EXPECTED TO BUILD THROUGH MUCH OF THE
WEEK, KEEPING US DRY AND MAINTAINING SEASONABLY NORMAL
TEMPERATURES. HOWEVER, THE ECMWF SOLUTION SUGGEST A SHORT WAVE
DISTURBANCE DIGGING ACROSS FAR NORTHWEST OKLAHOMA FOR THURSDAY
NIGHT. FOR NOW, WILL BE KEEPING ANY POPS OUT OF THERE, MAINLY DUE
TO UNCERTAINTY OF MOISTURE AVAILABILITY.
A MUCH DEEPER TROUGH WILL BE DIGGING ACROSS THE NORTHERN U.S.
DURING THE WEEKEND, WHICH WILL BE PUSHING A COLD FRONT INTO OUR
AREA BEGINNING FOR MONDAY. AT THIS POINT, BOTH LONG RANGE MODELS
HINT A PACIFIC BASED MIDLEVEL MOISTURE PLUME, ORIGINATING FROM THE
GULF OF CALIFORNIA, EXTENDING INTO NORTHWEST OKLAHOMA BEGINNING
SUNDAY. WITH THE COLD FRONT APPROACHING NEAR THE TIME PERIOD, IT
WOULD CERTAINLY NOT RULE OUT LOW TSRA POPS IN OUR NORTHWEST FOR
THE SUNDAY THROUGH MONDAY TIME FRAME.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 71 92 70 92 / 0 0 0 0
HOBART OK 70 95 71 95 / 0 0 0 0
WICHITA FALLS TX 72 95 71 95 / 0 0 0 0
GAGE OK 69 94 70 94 / 0 0 10 0
PONCA CITY OK 71 93 70 92 / 0 0 0 0
DURANT OK 71 94 71 94 / 10 10 10 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORMAN OK
656 PM CDT MON AUG 31 2015
.AVIATION...
VFR CONDITIONS AND A SOUTH WIND WILL PREVAIL THROUGH 00Z
WEDNESDAY.
&&
.PREV DISCUSSION... /ISSUED 326 PM CDT MON AUG 31 2015/
DISCUSSION...
A WEAK UPPER LOW CONTINUES TO SPIN ACROSS SOUTHEAST OKLAHOMA.
ALTHOUGH LATEST RAP & HRRR RUNS KEEP IT INACTIVE THERE, WATER
VAPOR IMAGERY CONTINUES TO SHOW A SLIGHT MIDLEVEL CIRCULATION,
ENOUGH TO MAINTAIN LOW TSRA POPS THERE UNTIL THIS EVENING.
OTHERWISE, AN UPPER RIDGE IS EXPECTED TO BUILD THROUGH MUCH OF THE
WEEK, KEEPING US DRY AND MAINTAINING SEASONABLY NORMAL
TEMPERATURES. HOWEVER, THE ECMWF SOLUTION SUGGEST A SHORT WAVE
DISTURBANCE DIGGING ACROSS FAR NORTHWEST OKLAHOMA FOR THURSDAY
NIGHT. FOR NOW, WILL BE KEEPING ANY POPS OUT OF THERE, MAINLY DUE
TO UNCERTAINTY OF MOISTURE AVAILABILITY.
A MUCH DEEPER TROUGH WILL BE DIGGING ACROSS THE NORTHERN U.S.
DURING THE WEEKEND, WHICH WILL BE PUSHING A COLD FRONT INTO OUR
AREA BEGINNING FOR MONDAY. AT THIS POINT, BOTH LONG RANGE MODELS
HINT A PACIFIC BASED MIDLEVEL MOISTURE PLUME, ORIGINATING FROM THE
GULF OF CALIFORNIA, EXTENDING INTO NORTHWEST OKLAHOMA BEGINNING
SUNDAY. WITH THE COLD FRONT APPROACHING NEAR THE TIME PERIOD, IT
WOULD CERTAINLY NOT RULE OUT LOW TSRA POPS IN OUR NORTHWEST FOR
THE SUNDAY THROUGH MONDAY TIME FRAME.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 71 92 70 92 / 0 0 0 0
HOBART OK 70 95 71 95 / 0 0 0 0
WICHITA FALLS TX 72 95 71 95 / 0 0 0 0
GAGE OK 69 94 70 94 / 0 0 10 0
PONCA CITY OK 71 93 70 92 / 0 0 0 0
DURANT OK 71 94 71 94 / 10 10 10 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORMAN OK
220 PM CDT SUN AUG 30 2015
.DISCUSSION...
MAINLY DRY WEATHER AND NEAR OR SLIGHTLY ABOVE AVERAGE TEMPERATURES
ARE EXPECTED DURING THE NEXT SEVEN DAYS.
THROUGH 10 PM THIS EVENING...A FEW THUNDERSTORMS MAY FORM NEAR A
WEAK SURFACE FRONT OVER SOUTHERN OKLAHOMA...NEAR WAURIKA TO
COALGATE. CAPPING IS RATHER STRONG...HOWEVER A MID LEVEL
WEAKNESS CENTERED OVER EASTERN OKLAHOMA MAY BE ENOUGH FOR TO
ALLOW FOR ISOLATED DEVELOPMENT. THUS...WENT WITH A 20 PERCENT
CHANCE IN THESE LOCATIONS. IF STORMS FORM...THEY WOULD BE SLOW
MOVERS...PRODUCE LOCALIZED DOWNPOURS...AND GUSTY WINDS PERHAPS UP
TO 50 TO 60 MPH. ANY CONVECTION WOULD DIMINISH WITH THE LOSS OF
DAYTIME HEATING.
AFTER 10 PM THIS EVENING INTO MONDAY MORNING...PATCHY FOG MAY FORM
AGAIN ACROSS MAINLY NORTHERN OKLAHOMA. LATEST HRRR RUNS HAVE BEEN
CONSISTENT WITH DEPICTING LOW CLOUDS AND FOG OVER NEAR ALVA...
ENID...AND CHEROKEE. THIS SEEMS REASONABLE AS HIGHER SURFACE
DEWPOINTS ARE FORECAST TO MOVE INTO THESE LOCATIONS LATE TONIGHT.
THUS...ADDED MENTION OF PATCHY FOG. DOUBT FOG WILL BE TOO DENSE
OR WIDESPREAD SINCE NO RAIN WILL OCCUR IN THESE LOCATIONS TODAY.
MONDAY WILL BE MOSTLY SUNNY AND HOTTER WITH INCREASING SOUTH
SURFACE WINDS. CANNOT COMPLETELY RULE OUT A STRAY AFTERNOON OR
EVENING STORM IN SOUTHEAST OF A WAURIKA TO ADA LINE WHERE MID
LEVEL TEMPERATURES WILL BE A BIT COOLER AND CAPPING IS A BIT
WEAKER...BUT WILL NOT MENTION DUE TO LOW CONFIDENCE OF OCCURRENCE.
MONDAY NIGHT THROUGH NEXT SUNDAY...SEASONABLY HOT AND MAINLY DRY
WEATHER WILL CONTINUE WITH A WEAK MID/UPPER RIDGE OVERHEAD. LOW
STORM CHANCES MAY RETURN TO MAINLY NORTHWESTERN OKLAHOMA BY THE
WEEKEND...BUT CONFIDENCE IS LOW.
MBS
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 66 93 70 92 / 0 0 0 0
HOBART OK 65 97 71 96 / 0 0 0 0
WICHITA FALLS TX 69 97 72 97 / 0 0 0 0
GAGE OK 62 96 69 95 / 0 0 0 0
PONCA CITY OK 66 93 70 93 / 0 0 0 0
DURANT OK 71 95 71 94 / 20 10 0 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
26/17
AREA FORECAST DISCUSSION
NWS NORMAN OK
1226 PM CDT SUN AUG 30 2015
.DISCUSSION...
AVIATION DISCUSSION FOR THE 18Z TAFS IS BELOW.
&&
.AVIATION...
VFR CONDITIONS ARE GENERALLY EXPECTED. SURFACE WINDS SHOULD STAY
BELOW 10 KT AT ALL LOCATIONS THROUGH 14Z MONDAY BEFORE INCREASING.
PATCHES OF MVFR OR LOWER CONDITIONS WITH BR MAY OCCUR 07-15Z
MAINLY OVER NORTHERN OKLAHOMA...BUT DID NOT MENTION IN TAFS DUE
LOW CONFIDENCE OF OCCURRENCE.
MBS
&&
.PREV DISCUSSION... /ISSUED 1113 AM CDT SUN AUG 30 2015/
DISCUSSION...
THE UPDATE THIS MORNING IS MAINLY TO REMOVE MENTION OF FOG AND
MORNING THUNDER. FOG HAS CLEARED ALL OF THE OBSERVATION SITES. IF
THERE IS SOME LINGERING FOG OVER ALFALFA/GRANT COUNTIES... DO NOT
EXPECT IT TO REMAIN LONG AND CONDITIONS WILL CONTINUE TO IMPROVE.
TO THE SOUTH... ONE ISOLATED SHOWER IS DRIFTING ACROSS BRYAN
COUNTY... BUT OTHERWISE HAVE SEEN NO SIGNIFICANT DEVELOPMENT. WILL
KEEP THE MENTION OF ISOLATED SHOWER FOR THE MORNING HOURS BUT
REDUCE POPS TO LESS THAN 20. STILL SOME MIXED SIGNALS FOR
REDEVELOPMENT THIS AFTERNOON IN THE SOUTHEAST AND WILL LEAVE THE
LOW AFTERNOON POPS IN THE SOUTHEAST.
PREV DISCUSSION... /ISSUED 646 AM CDT SUN AUG 30 2015/
DISCUSSION...
30/12Z TAF ISSUANCE.
AVIATION...
LIFR CONDITIONS IN FOG/STRATUS ARE EXPECTED ACROSS NORTHERN
OKLAHOMA TERMINALS THROUGH 15Z. WILL ALSO MENTION MVFR FOG OVER
CENTRAL OKLAHOMA TERMINALS OF KOKC/KOUN FIRST FEW HOURS OF
FORECAST. OTHERWISE VFR FORECAST WITH LIGHT NORTHERLY WINDS
BECOMING LIGHT SOUTHERLY LATE IN THE AFTERNOON AND TONIGHT.
PREV DISCUSSION... /ISSUED 406 AM CDT SUN AUG 30 2015/
DISCUSSION...
MAIN ADJUSTMENT TO GOING FORECAST PACKAGE WAS TO ADD FOG FOR THIS
MORNING ACROSS AREAS NORTH OF I-40. THE MOST WIDESPREAD AND
POSSIBLY DENSE FOG WILL BE OVER FAR NORTH/NORTHWEST OKLAHOMA
NEAREST LOW LEVEL RIDGE AXIS. CONFIDENT THAT THERE WILL BE FOG BUT
JUST NOT SURE HOW WIDESPREAD ANY DENSE FOG WILL BE. THE MOST
AGGRESSIVE MODELS...WRF AND HRRR KEEP A MAJORITY OF DENSE FOG UP
IN KANSAS THROUGH 9 AM. DENSE FOG ADVISORY NOT ANTICIPATED AT THIS
POINT BUT WE WILL WATCH TRENDS AND ISSUE AS NEEDED. POPS WERE ALSO
CONTINUED THROUGH TODAY ACROSS SOUTHEAST CWA NEAR MID-LEVEL SHEAR
AXIS AND EFFECTIVE SYNOPTIC BOUNDARY.
TODAYS TEMPS WERE COOLED A BIT FROM PREVIOUS FORECAST AS WELL.
INITIALIZATIONS CAME IN A FEW DEGREES COOLER MAINLY OVER NORTHERN
AND WESTERN OKLAHOMA...AND WITH PLUME OF HIGH LEVEL SMOKE THIS
SOUNDS REASONABLE. GFS AND ECM HAVE TRENDED WEAKER WITH THE UPPER
LEVEL RIDGE AND HAVE GENERALLY UNDERFORECAST STRENGTH/PERSISTENCE
OF LONGWAVE TROUGH AXIS JUST TO OUR EAST. THIS WILL YIELD SLIGHTLY
COOLER TEMPS THROUGH THE WEEK MOST AREAS AND ALTHOUGH POPS ARE TOO
LOW TO MENTION...CANNOT RULE OUT AN ISOLATED SHOWER OR WEAK STORM
ESPECIALLY FAR NORTHWEST OKLAHOMA CLOSER TO POSSIBLE HIGH PLAINS
REMNANTS AND FAR SOUTHEAST OKLAHOMA CLOSER TO UPPER TROUGH.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 68 93 70 92 / 0 0 0 0
HOBART OK 67 97 71 95 / 0 0 0 0
WICHITA FALLS TX 71 97 72 96 / 0 0 0 0
GAGE OK 63 96 69 94 / 0 0 0 0
PONCA CITY OK 67 93 70 93 / 0 0 0 0
DURANT OK 71 95 71 94 / 10 10 0 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
26/17/17
AREA FORECAST DISCUSSION
NWS NORMAN OK
1113 AM CDT SUN AUG 30 2015
.DISCUSSION...
THE UPDATE THIS MORNING IS MAINLY TO REMOVE MENTION OF FOG AND
MORNING THUNDER. FOG HAS CLEARED ALL OF THE OBSERVATION SITES. IF
THERE IS SOME LINGERING FOG OVER ALFALFA/GRANT COUNTIES... DO NOT
EXPECT IT TO REMAIN LONG AND CONDITIONS WILL CONTINUE TO IMPROVE.
TO THE SOUTH... ONE ISOLATED SHOWER IS DRIFTING ACROSS BRYAN
COUNTY... BUT OTHERWISE HAVE SEEN NO SIGNIFICANT DEVELOPMENT. WILL
KEEP THE MENTION OF ISOLATED SHOWER FOR THE MORNING HOURS BUT
REDUCE POPS TO LESS THAN 20. STILL SOME MIXED SIGNALS FOR
REDEVELOPMENT THIS AFTERNOON IN THE SOUTHEAST AND WILL LEAVE THE
LOW AFTERNOON POPS IN THE SOUTHEAST.
&&
.PREV DISCUSSION... /ISSUED 646 AM CDT SUN AUG 30 2015/
DISCUSSION...
30/12Z TAF ISSUANCE.
AVIATION...
LIFR CONDITIONS IN FOG/STRATUS ARE EXPECTED ACROSS NORTHERN
OKLAHOMA TERMINALS THROUGH 15Z. WILL ALSO MENTION MVFR FOG OVER
CENTRAL OKLAHOMA TERMINALS OF KOKC/KOUN FIRST FEW HOURS OF
FORECAST. OTHERWISE VFR FORECAST WITH LIGHT NORTHERLY WINDS
BECOMING LIGHT SOUTHERLY LATE IN THE AFTERNOON AND TONIGHT.
PREV DISCUSSION... /ISSUED 406 AM CDT SUN AUG 30 2015/
DISCUSSION...
MAIN ADJUSTMENT TO GOING FORECAST PACKAGE WAS TO ADD FOG FOR THIS
MORNING ACROSS AREAS NORTH OF I-40. THE MOST WIDESPREAD AND
POSSIBLY DENSE FOG WILL BE OVER FAR NORTH/NORTHWEST OKLAHOMA
NEAREST LOW LEVEL RIDGE AXIS. CONFIDENT THAT THERE WILL BE FOG BUT
JUST NOT SURE HOW WIDESPREAD ANY DENSE FOG WILL BE. THE MOST
AGGRESSIVE MODELS...WRF AND HRRR KEEP A MAJORITY OF DENSE FOG UP
IN KANSAS THROUGH 9 AM. DENSE FOG ADVISORY NOT ANTICIPATED AT THIS
POINT BUT WE WILL WATCH TRENDS AND ISSUE AS NEEDED. POPS WERE ALSO
CONTINUED THROUGH TODAY ACROSS SOUTHEAST CWA NEAR MID-LEVEL SHEAR
AXIS AND EFFECTIVE SYNOPTIC BOUNDARY.
TODAYS TEMPS WERE COOLED A BIT FROM PREVIOUS FORECAST AS WELL.
INITIALIZATIONS CAME IN A FEW DEGREES COOLER MAINLY OVER NORTHERN
AND WESTERN OKLAHOMA...AND WITH PLUME OF HIGH LEVEL SMOKE THIS
SOUNDS REASONABLE. GFS AND ECM HAVE TRENDED WEAKER WITH THE UPPER
LEVEL RIDGE AND HAVE GENERALLY UNDERFORECAST STRENGTH/PERSISTENCE
OF LONGWAVE TROUGH AXIS JUST TO OUR EAST. THIS WILL YIELD SLIGHTLY
COOLER TEMPS THROUGH THE WEEK MOST AREAS AND ALTHOUGH POPS ARE TOO
LOW TO MENTION...CANNOT RULE OUT AN ISOLATED SHOWER OR WEAK STORM
ESPECIALLY FAR NORTHWEST OKLAHOMA CLOSER TO POSSIBLE HIGH PLAINS
REMNANTS AND FAR SOUTHEAST OKLAHOMA CLOSER TO UPPER TROUGH.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 89 68 93 70 / 10 0 0 0
HOBART OK 92 67 97 71 / 0 0 0 0
WICHITA FALLS TX 96 71 97 72 / 10 0 0 0
GAGE OK 91 63 96 69 / 0 0 0 0
PONCA CITY OK 88 67 93 70 / 0 0 0 0
DURANT OK 94 71 95 71 / 10 10 10 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
99/99
AREA FORECAST DISCUSSION...UPDATED
NWS NORMAN OK
646 AM CDT SUN AUG 30 2015
.DISCUSSION...
30/12Z TAF ISSUANCE.
&&
.AVIATION...
LIFR CONDITIONS IN FOG/STRATUS ARE EXPECTED ACROSS NORTHERN
OKLAHOMA TERMINALS THROUGH 15Z. WILL ALSO MENTION MVFR FOG OVER
CENTRAL OKLAHOMA TERMINALS OF KOKC/KOUN FIRST FEW HOURS OF
FORECAST. OTHERWISE VFR FORECAST WITH LIGHT NORTHERLY WINDS
BECOMING LIGHT SOUTHERLY LATE IN THE AFTERNOON AND TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 406 AM CDT SUN AUG 30 2015/
DISCUSSION...
MAIN ADJUSTMENT TO GOING FORECAST PACKAGE WAS TO ADD FOG FOR THIS
MORNING ACROSS AREAS NORTH OF I-40. THE MOST WIDESPREAD AND
POSSIBLY DENSE FOG WILL BE OVER FAR NORTH/NORTHWEST OKLAHOMA
NEAREST LOW LEVEL RIDGE AXIS. CONFIDENT THAT THERE WILL BE FOG BUT
JUST NOT SURE HOW WIDESPREAD ANY DENSE FOG WILL BE. THE MOST
AGGRESSIVE MODELS...WRF AND HRRR KEEP A MAJORITY OF DENSE FOG UP
IN KANSAS THROUGH 9 AM. DENSE FOG ADVISORY NOT ANTICIPATED AT THIS
POINT BUT WE WILL WATCH TRENDS AND ISSUE AS NEEDED. POPS WERE ALSO
CONTINUED THROUGH TODAY ACROSS SOUTHEAST CWA NEAR MID-LEVEL SHEAR
AXIS AND EFFECTIVE SYNOPTIC BOUNDARY.
TODAYS TEMPS WERE COOLED A BIT FROM PREVIOUS FORECAST AS WELL.
INITIALIZATIONS CAME IN A FEW DEGREES COOLER MAINLY OVER NORTHERN
AND WESTERN OKLAHOMA...AND WITH PLUME OF HIGH LEVEL SMOKE THIS
SOUNDS REASONABLE. GFS AND ECM HAVE TRENDED WEAKER WITH THE UPPER
LEVEL RIDGE AND HAVE GENERALLY UNDERFORECAST STRENGTH/PERSISTENCE
OF LONGWAVE TROUGH AXIS JUST TO OUR EAST. THIS WILL YIELD SLIGHTLY
COOLER TEMPS THROUGH THE WEEK MOST AREAS AND ALTHOUGH POPS ARE TOO
LOW TO MENTION...CANNOT RULE OUT AN ISOLATED SHOWER OR WEAK STORM
ESPECIALLY FAR NORTHWEST OKLAHOMA CLOSER TO POSSIBLE HIGH PLAINS
REMNANTS AND FAR SOUTHEAST OKLAHOMA CLOSER TO UPPER TROUGH.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 89 68 93 70 / 10 0 0 0
HOBART OK 92 67 97 71 / 10 0 0 0
WICHITA FALLS TX 96 71 97 72 / 10 0 0 0
GAGE OK 91 63 96 69 / 10 0 0 0
PONCA CITY OK 88 67 93 70 / 10 0 0 0
DURANT OK 94 71 95 71 / 20 10 10 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
23/11/11
AREA FORECAST DISCUSSION
NWS NORMAN OK
406 AM CDT SUN AUG 30 2015
.DISCUSSION...
MAIN ADJUSTMENT TO GOING FORECAST PACKAGE WAS TO ADD FOG FOR THIS
MORNING ACROSS AREAS NORTH OF I-40. THE MOST WIDESPREAD AND
POSSIBLY DENSE FOG WILL BE OVER FAR NORTH/NORTHWEST OKLAHOMA
NEAREST LOW LEVEL RIDGE AXIS. CONFIDENT THAT THERE WILL BE FOG BUT
JUST NOT SURE HOW WIDESPREAD ANY DENSE FOG WILL BE. THE MOST
AGGRESSIVE MODELS...WRF AND HRRR KEEP A MAJORITY OF DENSE FOG UP
IN KANSAS THROUGH 9 AM. DENSE FOG ADVISORY NOT ANTICIPATED AT THIS
POINT BUT WE WILL WATCH TRENDS AND ISSUE AS NEEDED. POPS WERE ALSO
CONTINUED THROUGH TODAY ACROSS SOUTHEAST CWA NEAR MID-LEVEL SHEAR
AXIS AND EFFECTIVE SYNOPTIC BOUNDARY.
TODAYS TEMPS WERE COOLED A BIT FROM PREVIOUS FORECAST AS WELL.
INITIALIZATIONS CAME IN A FEW DEGREES COOLER MAINLY OVER NORTHERN
AND WESTERN OKLAHOMA...AND WITH PLUME OF HIGH LEVEL SMOKE THIS
SOUNDS REASONABLE. GFS AND ECM HAVE TRENDED WEAKER WITH THE UPPER
LEVEL RIDGE AND HAVE GENERALLY UNDERFORECAST STRENGTH/PERSISTENCE
OF LONGWAVE TROUGH AXIS JUST TO OUR EAST. THIS WILL YIELD SLIGHTLY
COOLER TEMPS THROUGH THE WEEK MOST AREAS AND ALTHOUGH POPS ARE TOO
LOW TO MENTION...CANNOT RULE OUT AN ISOLATED SHOWER OR WEAK STORM
ESPECIALLY FAR NORTHWEST OKLAHOMA CLOSER TO POSSIBLE HIGH PLAINS
REMNANTS AND FAR SOUTHEAST OKLAHOMA CLOSER TO UPPER TROUGH.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 89 68 93 70 / 0 0 0 0
HOBART OK 92 67 97 71 / 0 0 0 0
WICHITA FALLS TX 96 71 97 72 / 10 0 0 0
GAGE OK 91 63 96 69 / 0 0 0 0
PONCA CITY OK 88 67 93 70 / 0 0 0 0
DURANT OK 94 71 95 71 / 20 10 10 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
23/11
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
411 AM EDT SUN AUG 30 2015
.SYNOPSIS...
INCREASING MOISTURE WILL BE CHANNELED NORTHEAST FROM THE OHIO
VALLEY TODAY...AND INTERACT WITH A STATIONARY FRONTAL BOUNDARY TO
PRODUCE SCATTERED SHOWERS AND A FEW THUNDERSTORMS ACROSS MAINLY
THE NORTHWESTERN HALF OF THE STATE. HIGH PRESSURE OFF THE MID
ATLANTIC COAST WILL BE MORE INFLUENTIAL ON KEEPING FAIR AND DRY
WEATHER INTACT ACROSS THE SOUTHEASTERN HALF OF PENNSYLVANIA.
VERY WARM AND INCREASINGLY HUMID WEATHER WILL CONTINUE INTO THE
MIDDLE OF THE UPCOMING WEEK.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
STABLE STRATIFICATION UNDER CLEAR TO PTLY CLOUDY SKIES WILL
CONTINUE ACROSS MUCH OF CENTRAL AND SOUTHERN PENN THROUGH THE MID
MORNING HOURS. OVER NWRN PENN.
SFC BASED CAPE WILL SLOWLY INCREASE TO BETWEEN 300-500 J/KG
ACROSS THE NW MTNS THIS MORNING WITH THE ADVECTION OF 1.5 INCH
PWAT AIR FROM THE OHIO VALLEY. THE PRESENCE OF A QUASI-STNRY
FRONTAL BOUNDARY AND THE INCREASING MOISTURE FROM THE OHIO
VALLEY...WILL LEAD TO NEWRD EXPANSION OF SHOWERS AND A FEW
ISOLATED TSRA EARLY TODAY.
PATCHY LIGHT RIVER VALLEY FOG EXPECTED ELSEWHERE AS SFC DEWPOINTS
SLOWLY RISE.
MIN TEMPS SHOULD RANGE FROM THE MID TO UPPER 50S OVER THE NORTH...
TO THE LOWER 60S IN THE SOUTHEAST.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH 6 PM MONDAY/...
SOME EARLY MORNING FOG IN THE VALLEYS - WHICH SHOULD BE OF LESSER
COVERAGE THAN SAT MORNING. THEN...THE TEMPS RISE EVEN
BETTER...ADDING ANOTHER 3-4F ONTO SAT/S MAXES.
RIDGE AT THE SFC AND ALOFT IS STARTING TO GET PRESSED A LITTLE TO
THE EAST BY AN ADVANCING UPPER TROUGH AND SLIGHT FEED OF GULF
MOISTURE. THUS...SUPPORT IN THE FORM OF INSTABILITY AND MOISTURE
WILL BE AVAILABLE TODAY.
PLAN TO INCREASE POPS INTO THE LIKELY CATEGORY ACROSS THE NW MTNS
DURING THE MID TO LATE MORNING HOURS. THERE WILL BE A TRANSITION
TO VIRTUALLY NO CHC OF RAIN OVER THE SE COUNTIES OF OUR CWA.
CONVECTIVE ALLOWING HRRR MODEL SUGGEST EVEN CATEGORICAL ARE
WARRANTED ACROSS PARTS OF THE NW AND NCENT MTNS /AND EVEN FOR A
MORE BRIEF TIME PERIOD OF A FEW HOURS OVER THE LAUREL HIGHLANDS
CENTERED ON DAYBREAK/. THIS SECOND...AND MORE SIGNIFICANT CLUSTER
OF CONVECTION WILL IMPACT THE NW MTNS OF PENN BETWEEN 10-14Z.SOME
LOCATIONS WILL SEE BETWEEN 0.25 AND 0.50 INCH OF RAIN...WHERE TWO
OR MORE MDT-HVY SHOWERS OCCUR.
AFTER THE INITIAL...RATHER COMPACT SHORTWAVE ALOFT LIFTS INTO
SOUTHCENTRAL NEW YORK LATER THIS MORNING...THE ATMOS WILL RECHARGE
TO OVER 1000 J/KG CAPE IN SOME AREAS...AND BE CAPABLE OF FIRING
OFF SCTD SHRA/TSRA ACROSS THE CENTRAL MTNS...AND ALLEGHENIES THIS
AFTERNOON.
HIGHS THIS AFTERNOON WILL VARY FROM THE U70S ACROSS THE NRN AND
WRN MTNS...TO THE UPPER 80S ACROSS THE LOWER SUSQ VALLEY AND
SURROUNDING AREAS.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
ANOMALOUS UPPER LEVEL RIDGE WILL DOMINATE THE OHIO VALLEY AND
EASTERN UNITED STATES MUCH OF THE UPCOMING WEEK...WITH 850HPA
TEMPS RUNNING 16-18C WHICH WILL TRANSLATE TO WELL ABOVE-NORMAL
SFC TEMPS. THIS WARMTH AND INCREASING HUMIDITY SHOULD ALLOW FOR
AT LEAST A SLIGHT CHC FOR DIURNAL CONVECTION EACH DAY...BUT THE
PROBABILITY OF WIDESPREAD RAINFALL IS LOW.
THERE ARE A COUPLE OF INTERESTING FEATURES THAT BEAR WATCHING FOR
LATE IN THE LONG TERM PERIOD. THE FIRST IS THE REMNANTS OF
ERIKA...WHICH ARE FCST TO BE IN THE VICINITY OF THE FL/GA COAST BY
THE MIDDLE OF NEXT WEEK. AS THIS MOISTURE DIFFUSES OVER THE
SOUTHEAST U.S....SOME OF IT WILL GRADUALLY CRAWL INTO THE MID
ATLANTIC REGION. THE OTHER INTERESTING FEATURE IS A BACKDOOR COLD
FRONT THAT SOME MODELS BRING INTO THE MID-ATLANTIC STATES NEXT
THURS/FRI. THESE FEATURES COMBINED WITH THE WARM AND INCREASINGLY
HUMID AIR THAT WILL ALREADY BE IN PLACE WILL KEEP MENTION OF AT
LEAST A SLIGHT CHC FOR DIURNAL CONVECTION EACH DAY. THE LATTER
FEATURE COULD HAVE AN IMPACT ON TEMPS LATE NEXT WEEK...TAPERING
BACK TEMPS A BIT.
&&
.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
CONVECTION OUT AHEAD OF AN APPROACHING TROUGH IS CURRENTLY
STREAMING THROUGH NORTHWEST PA...AND SHOULD ALLOW FOR SOME LIGHT
SHOWERS BRINGING POSSIBLE MVFR CIGS/VSBYS TO BFD. OTHERWISE PATCHY
AREAS OF FOG MAINLY MVFR WITH SOME ISOLATED AREAS OF IFR. THOUGH
GENERALLY LIGHT WINDS...ANY REGION THAT DECOUPLES SHOULD SEE
INCREASE FOG FORMATION. IFR CONDITIONS HAVE THE HIGHEST CHANCE AT
UNV...AOO AND BFD.
CONSIDERING THE SHORT RANGE MODELS...EXPECT A HIGH CHANCE FOR
SHOWERS ACROSS NORTHERN PENNSYLVANIA THIS MORNING. BY 16Z SHOWERS
MOVE INTO SOUTHWEST MOUNTAINS. USED MAINLY VCSH/VCTS TO HANDLE
SHOWERS AS THE PROBABILITIES ARE GENERALLY 20 TO 40 PERCENT.
HIGHEST PROBABILITIES OF SHOWERS/THUNDER IN NORTHWEST.
OUTLOOK...
MON...STILL SOME SHRA/TSRA POSS.
TUE-THU...NO SIG WX EXPECTED AREAS MVFR OVERNIGHT PATCHY FOG.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...DANGELO/LAMBERT
LONG TERM...RXR
AVIATION...GRUMM/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
153 AM EDT SUN AUG 30 2015
.SYNOPSIS...
INCREASING MOISTURE WILL BE CHANNELED NORTHEAST FROM THE OHIO
VALLEY TODAY...AND INTERACT WITH A STATIONARY FRONTAL BOUNDARY TO
PRODUCE SCATTERED SHOWERS AND A FEW THUNDERSTORMS ACROSS MAINLY
THE NORTHWESTERN HALF OF THE STATE. HIGH PRESSURE OFF THE MID
ATLANTIC COAST WILL BE MORE INFLUENTIAL ON KEEPING FAIR AND DRY
WEATHER INTACT ACROSS THE SOUTHEASTERN HALF OF PENNSYLVANIA.
VERY WARM AND INCREASINGLY HUMID WEATHER WILL CONTINUE INTO THE
MIDDLE OF THE UPCOMING WEEK.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
STABLE STRATIFICATION UNDER CLEAR TO PTLY CLOUDY SKIES WILL
CONTINUE ACROSS MUCH OF CENTRAL AND SOUTHERN PENN THROUGH THE MID
MORNING HOURS. OVER NWRN PENN.
SFC BASED CAPE WILL SLOWLY INCREASE TO BETWEEN 300-500 J/KG
ACROSS THE NW MTNS THIS MORNING WITH THE ADVECTION OF 1.5 INCH
PWAT AIR FROM THE OHIO VALLEY. THE PRESENCE OF A QUASI-STNRY
FRONTAL BOUNDARY AND THE INCREASING MOISTURE FROM THE OHIO
VALLEY...WILL LEAD TO NEWRD EXPANSION OF SHOWERS AND A FEW
ISOLATED TSRA EARLY TODAY.
PATCHY LIGHT RIVER VALLEY FOG EXPECTED ELSEWHERE AS SFC DEWPOINTS
SLOWLY RISE.
MIN TEMPS SHOULD RANGE FROM THE MID TO UPPER 50S OVER THE NORTH...
TO THE LOWER 60S IN THE SOUTHEAST.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH 6 PM MONDAY/...
SOME EARLY MORNING FOG IN THE VALLEYS - WHICH SHOULD BE OF LESSER
COVERAGE THAN SAT MORNING. THEN...THE TEMPS RISE EVEN
BETTER...ADDING ANOTHER 3-4F ONTO SAT/S MAXES.
RIDGE AT THE SFC AND ALOFT IS STARTING TO GET PRESSED A LITTLE TO
THE EAST BY AN ADVANCING UPPER TROUGH AND SLIGHT FEED OF GULF
MOISTURE. THUS...SUPPORT IN THE FORM OF INSTABILITY AND MOISTURE
WILL BE AVAILABLE TODAY.
PLAN TO INCREASE POPS INTO THE LIKELY CATEGORY ACROSS THE NW MTNS
DURING THE MID TO LATE MORNING HOURS. THERE WILL BE A TRANSITION
TO VIRTUALLY NO CHC OF RAIN OVER THE SE COUNTIES OF OUR CWA.
CONVECTIVE ALLOWING HRRR MODEL SUGGEST EVEN CATEGORICAL ARE
WARRANTED ACROSS PARTS OF THE NW AND NCENT MTNS /AND EVEN FOR A
MORE BRIEF TIME PERIOD OF A FEW HOURS OVER THE LAUREL HIGHLANDS
CENTERED ON DAYBREAK/. THIS SECOND...AND MORE SIGNIFICANT CLUSTER
OF CONVECTION WILL IMPACT THE NW MTNS OF PENN BETWEEN 10-14Z.SOME
LOCATIONS WILL SEE BETWEEN 0.25 AND 0.50 INCH OF RAIN...WHERE TWO
OR MORE MDT-HVY SHOWERS OCCUR.
AFTER THE INITIAL...RATHER COMPACT SHORTWAVE ALOFT LIFTS INTO
SOUTHCENTRAL NEW YORK LATER THIS MORNING...THE ATMOS WILL RECHARGE
TO OVER 1000 J/KG CAPE IN SOME AREAS...AND BE CAPABLE OF FIRING
OFF SCTD SHRA/TSRA ACROSS THE CENTRAL MTNS...AND ALLEGHENIES THIS
AFTERNOON.
HIGHS THIS AFTERNOON WILL VARY FROM THE U70S ACROSS THE NRN AND
WRN MTNS...TO THE UPPER 80S ACROSS THE LOWER SUSQ VALLEY AND
SURROUNDING AREAS.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
ANOMALOUS UPPER LEVEL RIDGE WILL DOMINATE THE OHIO VALLEY AND
EASTERN UNITED STATES MUCH OF THE UPCOMING WEEK...WITH 850HPA
TEMPS RUNNING 16-18C WHICH WILL TRANSLATE TO WELL ABOVE-NORMAL
SFC TEMPS. THIS WARMTH AND INCREASING HUMIDITY SHOULD ALLOW FOR
AT LEAST A SLIGHT CHC FOR DIURNAL CONVECTION EACH DAY...BUT THE
PROBABILITY OF WIDESPREAD RAINFALL IS LOW.
THERE ARE A COUPLE OF INTERESTING FEATURES THAT BEAR WATCHING FOR
LATE IN THE LONG TERM PERIOD. THE FIRST IS THE REMNANTS OF
ERIKA...WHICH ARE FCST TO BE IN THE VICINITY OF THE FL/GA COAST BY
THE MIDDLE OF NEXT WEEK. AS THIS MOISTURE DIFFUSES OVER THE
SOUTHEAST U.S....SOME OF IT WILL GRADUALLY CRAWL INTO THE MID
ATLANTIC REGION. THE OTHER INTERESTING FEATURE IS A BACKDOOR COLD
FRONT THAT SOME MODELS BRING INTO THE MID-ATLANTIC STATES NEXT
THURS/FRI. THESE FEATURES COMBINED WITH THE WARM AND INCREASINGLY
HUMID AIR THAT WILL ALREADY BE IN PLACE WILL KEEP MENTION OF AT
LEAST A SLIGHT CHC FOR DIURNAL CONVECTION EACH DAY. THE LATTER
FEATURE COULD HAVE AN IMPACT ON TEMPS LATE NEXT WEEK...TAPERING
BACK TEMPS A BIT.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
SOME WEAK SHOWERS WILL MOVE ACROSS NORTHWESTERN PA BETWEEN 03 AND
06Z. VCTS IN KBFD. OTHERWISE PATCHY AREAS OF FOG MAINLY MVFR SOME
ISOLATED ARE IFR. MODELS SHOWS COULD BE SOME ISOLATED SHOWERS
BEFORE SUNRISE IN FAR WEST.
MOST MODELS SHOW HIGHEST CHANCE OF SHOWER ACROSS NORTHERN
PENNSYLVANIA SUNDAY IN THE MORNING. BY 16Z SHOWERS MOVE INTO
SOUTHWEST MOUNTAINS. USED MAINLY VCSH/VCTS TO HANDLE SHOWERS AS
THE PROBABILITIES ARE GENERALLY 20 TO 40 PERCENT. HIGHEST
PROBABILITIES OF SHOWERS/THUNDER IN NORTHWEST. KBFD WILL LIKELY
SEE A SHOWER SUNDAY.
OUTLOOK...
MON...STILL SOME SHRA/TSRA POSS.
TUE-THU...NO SIG WX EXPECTED AREAS MVFR OVERNIGHT PATCHY FOG.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT
LONG TERM...RXR
AVIATION...GRUMM
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
954 PM CDT MON AUG 31 2015
.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
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.
&&
$$
Johnson
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
642 PM CDT MON AUG 31 2015
.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
608 PM CDT MON AUG 31 2015
.AVIATION...
/12Z 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 0 0
San Angelo 69 95 70 95 / 5 5 5 5
Junction 67 93 69 91 / 10 5 5 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
21
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
135 PM EDT SUN AUG 30 2015
.SYNOPSIS...
A SERIES OF WEAK UPPER LEVEL DISTURBANCES WILL LIFT NORTH ALONG
THE APPALACHIAN CHAIN THIS AFTERNOON INTO EARLY MONDAY...BRINGING
A GREATER CHANCE FOR SHOWERS TO THE REGION. UPPER LEVEL HIGH
PRESSURE WILL THEN STRENGTHEN AND KEEP US IN A RATHER STAGNANT
PATTERN...MAINTAINING A CHANCE FOR AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS THROUGH THE MIDDLE OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM EDT SUNDAY...
RADAR HAS SHOWN A SLOW INCREASE IN LIGHT REFLECTIVITY OVER THE
PAST COUPLE HOURS. THE VAST MAJORITY OF THE MOISTURE IS NOT
REACHING THE SURFACE...HOWEVER KEEPING CHANCE POPS IN EARLY THIS
AFTERNOON FOR THE OCCASIONAL SPRINKLE OR BRIEF LIGHT SHOWER ACROSS
THE MOUNTAINS. HRRR AND RAP CONTINUE TO SHOW SPOTTY PRECIPITATION
LATER THIS AFTERNOON MAINLY ACROSS THE MOUNTAINS...HOWEVER
CONTINUING WITH THE TREND OF JUST CHANCE POPS. BUMPED UP HIGH
TEMPS A BIT OUT EAST WHERE THEY HAVE HAD SOME DECENT CLEARING AND
MORE SUNSHINE.
AS OF 915 AM EDT SUNDAY...
ONLY MINOR ADJUSTMENTS TO THE NEAR TERM FORECAST. AN AREA OF
SPRINKLES/LIGHT RAIN MOVED ACROSS NW NC WITH LIGHT DRIZZLE
REPORTED AT TNB AND UKF AROUND 13Z. UPPER AIR SOUNDING AT 12Z
SHOWS THE COLUMN BEGINNING TO MOISTEN UP...HOWEVER THE LOW LEVELS
ARE STILL FAIRLY DRY SO ANY PRECIPITATION OUT OF THIS MORNINGS MID
DECK WILL BE CONFINED TO JUST A FEW SPRINKLES. ALL OTHER FORECAST
DETAILS REMAIN ON TRACK.
AS OF 715 AM EDT SUNDAY...
RADAR INDICATING LIGHT RETURNS ACROSS NORTH CAROLINA APPROACHING
OUR AREA THIS MORNING. VERY LITTLE OF THIS IS REACHING THE
GROUND...HOWEVER RAISED RAIN CHANCES SLIGHTLY DURING THE MORNING
TO ACCOUNT FOR ANY INCREASES IN THE COVERAGE OF SHOWER ACTIVITY.
OTHERWISE...THE EARLY MORNING FORECAST REMAINS ON TRACK.
AS OF 345 AM EDT SUNDAY...
STARTING THE MORNING OFF WITH A BROAD BUT WEAK UPPER LEVEL TROUGH
SITUATED FROM THE GREAT LAKES SOUTHWARD ALONG THE MISSISSIPPI RIVER
VALLEY...WHILE SUBTROPICAL RIDGING REMAINS PARKED OFF THE ATLANTIC
COAST OF THE SOUTHEAST STATES. THIS PATTERN IS MAKING FOR
SOUTHWESTERLY WINDFLOW ALOFT FOR THE MID ATLANTIC...WHICH WILL CARRY
A SERIES OF WEAK DISTURBANCE NORTHWARD ALONG THE APPALACHIAN CHAIN.
FOR TODAY...EXPECT THE MID AND HIGH CLOUDS CURRENTLY IN PLACE TO
LINGER THROUGH THE DAY...ALTHOUGH BRIEF BREAKS WILL OCCUR AT TIMES.
SOUTH SOUTHEASTERLY WINDS NEAR THE SURFACE WILL CONTINUE TO DRAW
MOISTURE INTO THE MOUNTAINS...AND EXPECT WE WILL SEE SHOWERS DEVELOP
DURING EARLY AFTERNOON ALONG THE RIDGES. THE MID AND HIGH CLOUDS
WILL KEEP INSTABILITY QUITE LIMITED...SO DO NOT REALLY MORE THAN
VERY ISOLATED AND BRIEF THUNDERSTORMS TO DEVELOP. AFTERNOON
TEMPERATURES WILL RANGE FROM THE MID 70S TO AROUND 80 ACROSS THE
MOUNTAINS...AND REACH INTO THE LOW/MID 80S ACROSS THE PIEDMONT.
SLIGHTLY BETTER CHANCES FOR SHOWER ACTIVITY ARE EXPECTED HEADING
INTO LATE SUNDAY EVENING AS A STRONGER UPPER LEVEL DISTURBANCE
APPROACHES FROM THE SOUTH. EVEN THEN...WEATHER FORECAST MODELS ARE
CALLING FOR THE BRUNT OF RAINFALL TO MISS OUR AREA TO THE
SOUTHEAST...AND BELIEVE THE PASSAGE OF THIS SYSTEM WILL AMOUNT TO
SPOTTY SHOWERS FOR THE MOUNTAINS...AND PERHAPS THE PIEDMONT SOUTH OF
HIGHWAY 460. SUNDAY NIGHT LOWS WILL RANGE FROM THE UPPER 50S AND LOW
60S WEST...TO THE MID 60S EAST.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
AS OF 400 AM EDT SUNDAY...
A WEAK UPPER LOW AND ASSOCIATED TROPICAL MOISTURE ASSOCIATED WITH
FORMER TROPICAL SYSTEMS DANNY AND ERIKA...WILL BE LIFTING NORTHEAST
ACROSS THE REGION MONDAY ON THE WESTERN PERIPHERY OF A BUILDING
SUBTROPICAL RIDGE ACROSS THE WESTERN ATLANTIC. MODEST LOW-LEVEL
MOISTURE INCREASE IS INDICATED WITH PRECIPITABLE WATER VALUES
CREEPING INTO THE 1.5/1.6 RANGE ACROSS MUCH OF THE CWA. AT THE SAME
TIME...HOWEVER...THE UPPER TROUGH IS WEAKENING AND SHEARING OUT. ON
THE OTHER END OF THE CWA A DIFFUSE AND STALLING FRONT BOUNDARY WILL
BE LOCATED JUST TO OUR NORTH WITH THE ASSOCIATED UPPER AIR SUPPORT
HAVING LIFTED WELL NORTHEAST OF THIS REGION. DESPITE THESE WEAK
SYSTEMS...THE UNDERLYING THEME WILL BE A BROAD SUBTROPICAL RIDGE
BUILDING ACROSS MUCH OF THE EASTERN 2/3RDS OF THE U.S.
SUFFICIENT MOISTURE...INSTABILITY...AND DYNAMICS...GIVEN THE
FRONT TO THE NORTH AND UPPER TROUGH LIFTING ACROSS THE REGION...
SHOULD BE PRESENT MONDAY TO SUPPORT ISOLATED TO SCATTERED DIURNAL
CONVECTION...WITH A FEW SPRINKLES OR LIGHT SHOWERS EVEN POSSIBLE
DURING THE MORNING...TYPICAL FOR A POCKET OF REMNANT TROPICAL
MOISTURE DRIFTING ACROSS THE REGION. AM NOT CONCERNED ABOUT A HEAVY
RAIN THREAT GIVEN THE LACK OF ANY FOCUSING MECHANISM AND NOTING THAT
THE PLUME OF DEEP TROPICAL MOISTURE REMAINS GENERALLY OFF THE EAST
COAST. MODEL QPF IS VERY LACKLUSTER...GENERALLY 1/4 INCH AMOUNTS AT
BEST. THIS AGREES WELL WITH WPC.
FOR TUE-WED...THE MAIN STORY WILL BE THE BUILDING UPPER RIDGE. ANY
VESTIGE OF THE TROPICAL SYSTEMS...FRONTAL BOUNDARY...AND UPPER
TROUGH IS COMPLETELY GONE IN THIS TIME FRAME WITH 588DM OR GREATER
HEIGHTS ENCOMPASSING MOST OF THE U.S. SOUTH OF THE CANADIAN
BORDER...WEST TO THE ROCKIES. A VERY WEAK UPPER LOW TROUGH
WILL LINGER ACROSS THE WESTERN TN VALLEY INTO THE SOUTHERN
PLAINS. LINGERING TRAPPED TROPICAL MOISTURE AND DIFFERENTIAL HEATING
ACROSS THE MOUNTAINS WILL LIKELY BE SUFFICIENT EACH AFTERNOON TO
TRIGGER ISOLATED CONVECTION...BUT LITTLE TO SUPPORT MORE THAN 30
POPS AT THIS TIME. BY WED AFTERNOON...THE GFS AND ECMWF BOTH DEPICT
A POTENTIAL BACKDOOR FRONT SLIPPING INTO THE REGION FROM THE
NORTHEAST...WITH A SLIGHT INCREASE IN CONVECTION POSSIBLE ACROSS THE
NORTHERN AREAS AS A RESULT.
TEMPERATURES WILL BE ON THE INCREASE THROUGH THE PERIOD AS 850MB
TEMPS RISE FROM THE CURRENT LEVELS AROUND +14C TO +16C TOWARD +20C
DURING THE PERIOD. THIS WILL SUPPORT HIGHER MAX TEMPS...WITH SOME
AREAS ACROSS THE PIEDMONT APPROACHING 90 DEGREES...WITH 75 TO 80
MOUNTAINS AND 80S ELSEWHERE. MIN TEMPS WILL ALSO BE ON THE INCREASE
WITH HIGHER DEWPOINTS/RH/PWATS IN PLACE THROUGH THE PERIOD. OVERALL
MIN TEMPS WILL AVERAGE 10 DEGREES ABOVE NORMAL THROUGH THE PERIOD
WITH MAX TEMPS ABOUT 5 DEGREES ABOVE AVERAGE.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 415 AM EDT SUNDAY...
THE EXTENDED PERIODS CONTINUE TO BE LARGELY DOMINATED BY A BROAD
LATE SUMMER UPPER RIDGE ACROSS THE EASTERN HALF OF THE U.S.
INCREASING TROUGHING ALONG THE WEST COAST WILL ALLOW THE UPPER RIDGE
TO PUSH FURTHER EAST...QUICKLY ERASING ANY MIDWEEK EFFECTS OF A
BACKDOOR FRONT AND WEAK SHORTWAVE TRAVERSING THE NORTHEASTERN
PERIPHERY OF THE UPPER RIDGE. TROPICAL MOISTURE WILL LINGER ACROSS
THE REGION WITH NO CHANGE IN AIR MASS EXPECTED. ON THE OTHER
HAND...THERE IS SIMPLY NO SYNOPTIC/DYNAMIC TRIGGERING MECHANISM.
THIS LEAVES CONVECTION TO BE DRIVEN ENTIRELY BY DIFFERENTIAL DIURNAL
HEATING THROUGH THE END OF THE WORK WEEK.
TEMPERATURES ARE EXPECTED TO CONTINUE ABOVE NORMAL THROUGH THE
PERIOD WITH HIGHS 75 TO 80 MOUNTAINS AND 80S ELSEWHERE...NEAR 90
ACROSS THE PIEDMONT. MIN TEMPS WILL BE MORE SIGNIFICANTLY ABOVE
NORMAL WITH MAINLY 60S TO NEAR 70 PIEDMONT. THESE READINGS ARE 5 TO
10 DEGREES ABOVE NORMAL.
LOOKING AHEAD...SOME MODELS ARE ADVERTISING PERHAPS THE FIRST FALL
COLD FRONT INTO THE FOLLOWING WEEK...BUT ENTIRELY TOO FAR OUT TO
PUT ANY CREDIBILITY IN AT THIS POINT.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 130 PM EDT SUNDAY...
WILL GO WITH A LIGHT WIND VFR FORECAST THROUGH THE PERIOD AT ALL
SITES...BUT WITH SOME CAVEATS. DIURNAL SHOWERS ARE DEVELOPING
AHEAD OF INCREASING MOISTURE AND A SHORT WAVE APPROACHING FROM THE
SOUTH. LOW LEVEL DRY AIR IS SLOW TO SATURATE DESPITE GOOD
TRANSPORT OF TROPICAL MOISTURE ALOFT FROM THE GULF OF MEXICO. THE
RESULT IS ABUNDANT MID/UPPER CLOUDS... SPOTTY SHOWERS/SPRINKLES...
AND NO SUB VFR CIGS. BELIEVE THIS WILL CONTINUE TO BE THE CASE
INTO EARLY THIS EVENING AS DIURNAL ACTIVITY STARTS TO WANE WITH
THE LOSS OF HEATING SO WILL GO WITH VFR CONDITIONS AND VCSH
THROUGH THE FIRST PART OF THE TAFS.
HOWEVER...THE APPROACHING WAVE LOOKS TO BRING ANOTHER CHANCE OF SHOWERS
IN FOR THE OVERNIGHT. MODELS ARE QUITE DIFFERENT IN HANDLING PRECIPITATION
POTENTIAL AND ADVECTION OF LOW LEVEL MOISTURE SO DO NOT HAVE A LOT OF
CONFIDENCE IN SPECIFIC LOCATION/TIMING OF ANY SHOWERS AND LOWER CIGS.
THUS...WILL INDICATE A GRADUAL THICKENING/LOWERING OF VFR CLOUDS AND
LEAVE OUT MENTION OF PRECIPITATION FOR NOW. WILL USE VCSH ONLY AT KDAN
SINCE THEY WILL BE CLOSEST TO ADVANCING MOISTURE AND INTRODUCE SOME
LOWER VFR CIGS FOR KBLF/KBCB/KDAN LATE TONIGHT. BELIEVE THICKENING/LOWERING
CLOUDS WILL PREVENT FOG FORMATION SO WILL HEDGE AGAINST MOST GUIDANCE
AND NOT INCLUDE ANY FOG AT KBCB OR KLWB. THERE WILL BE MORE DIURNAL
SHOWERS AND POSSIBLY SUB VFR CIGS ON MONDAY BUT MOST LIKELY BEYOND
THIS TAF PERIOD.
EXTENDED AVIATION DISCUSSION... THE FORECAST AREA WILL REMAIN IN A
WEAKLY FORCED SYNOPTIC ENVIRONMENT THROUGH MIDWEEK...WITH CHANCES FOR
DIURNAL CONVECTION MAINLY FROM THE BLUE RIDGE WEST...AND SOME MVFR/IFR
FOG/STRATUS DEVELOPMENT AT NIGHT...ESPECIALLY AT KBCB AND KLWB.
&&
.EQUIPMENT...
AS OF 700 AM EDT SUNDAY...
THE DEW POINT READING AT KJFZ...RICHLANDS VA AWOS...IS INCORRECT.
AT THIS TIME WE DO NOT KNOW WHEN THIS SENSOR WILL BE REPAIRED.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...NF
NEAR TERM...CF/NF
SHORT TERM...RAB
LONG TERM...AMS/RAB
AVIATION...MBS/NF
EQUIPMENT...JR
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1243 PM EDT SUN AUG 30 2015
.SYNOPSIS...
A SERIES OF WEAK UPPER LEVEL DISTURBANCES WILL LIFT NORTH ALONG
THE APPALACHIAN CHAIN THIS AFTERNOON INTO EARLY MONDAY...BRINGING
A GREATER CHANCE FOR SHOWERS TO THE REGION. UPPER LEVEL HIGH
PRESSURE WILL THEN STRENGTHEN AND KEEP US IN A RATHER STAGNANT
PATTERN...MAINTAINING A CHANCE FOR AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS THROUGH THE MIDDLE OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM EDT SUNDAY...
RADAR HAS SHOWN A SLOW INCREASE IN LIGHT REFLECTIVITY OVER THE
PAST COUPLE HOURS. THE VAST MAJORITY OF THE MOISTURE IS NOT
REACHING THE SURFACE...HOWEVER KEEPING CHANCE POPS IN EARLY THIS
AFTERNOON FOR THE OCCASIONAL SPRINKLE OR BRIEF LIGHT SHOWER ACROSS
THE MOUNTAINS. HRRR AND RAP CONTINUE TO SHOW SPOTTY PRECIPITATION
LATER THIS AFTERNOON MAINLY ACROSS THE MOUNTAINS...HOWEVER
CONTINUING WITH THE TREND OF JUST CHANCE POPS. BUMPED UP HIGH
TEMPS A BIT OUT EAST WHERE THEY HAVE HAD SOME DECENT CLEARING AND
MORE SUNSHINE.
AS OF 915 AM EDT SUNDAY...
ONLY MINOR ADJUSTMENTS TO THE NEAR TERM FORECAST. AN AREA OF
SPRINKLES/LIGHT RAIN MOVED ACROSS NW NC WITH LIGHT DRIZZLE
REPORTED AT TNB AND UKF AROUND 13Z. UPPER AIR SOUNDING AT 12Z
SHOWS THE COLUMN BEGINNING TO MOISTEN UP...HOWEVER THE LOW LEVELS
ARE STILL FAIRLY DRY SO ANY PRECIPITATION OUT OF THIS MORNINGS MID
DECK WILL BE CONFINED TO JUST A FEW SPRINKLES. ALL OTHER FORECAST
DETAILS REMAIN ON TRACK.
AS OF 715 AM EDT SUNDAY...
RADAR INDICATING LIGHT RETURNS ACROSS NORTH CAROLINA APPROACHING
OUR AREA THIS MORNING. VERY LITTLE OF THIS IS REACHING THE
GROUND...HOWEVER RAISED RAIN CHANCES SLIGHTLY DURING THE MORNING
TO ACCOUNT FOR ANY INCREASES IN THE COVERAGE OF SHOWER ACTIVITY.
OTHERWISE...THE EARLY MORNING FORECAST REMAINS ON TRACK.
AS OF 345 AM EDT SUNDAY...
STARTING THE MORNING OFF WITH A BROAD BUT WEAK UPPER LEVEL TROUGH
SITUATED FROM THE GREAT LAKES SOUTHWARD ALONG THE MISSISSIPPI RIVER
VALLEY...WHILE SUBTROPICAL RIDGING REMAINS PARKED OFF THE ATLANTIC
COAST OF THE SOUTHEAST STATES. THIS PATTERN IS MAKING FOR
SOUTHWESTERLY WINDFLOW ALOFT FOR THE MID ATLANTIC...WHICH WILL CARRY
A SERIES OF WEAK DISTURBANCE NORTHWARD ALONG THE APPALACHIAN CHAIN.
FOR TODAY...EXPECT THE MID AND HIGH CLOUDS CURRENTLY IN PLACE TO
LINGER THROUGH THE DAY...ALTHOUGH BRIEF BREAKS WILL OCCUR AT TIMES.
SOUTH SOUTHEASTERLY WINDS NEAR THE SURFACE WILL CONTINUE TO DRAW
MOISTURE INTO THE MOUNTAINS...AND EXPECT WE WILL SEE SHOWERS DEVELOP
DURING EARLY AFTERNOON ALONG THE RIDGES. THE MID AND HIGH CLOUDS
WILL KEEP INSTABILITY QUITE LIMITED...SO DO NOT REALLY MORE THAN
VERY ISOLATED AND BRIEF THUNDERSTORMS TO DEVELOP. AFTERNOON
TEMPERATURES WILL RANGE FROM THE MID 70S TO AROUND 80 ACROSS THE
MOUNTAINS...AND REACH INTO THE LOW/MID 80S ACROSS THE PIEDMONT.
SLIGHTLY BETTER CHANCES FOR SHOWER ACTIVITY ARE EXPECTED HEADING
INTO LATE SUNDAY EVENING AS A STRONGER UPPER LEVEL DISTURBANCE
APPROACHES FROM THE SOUTH. EVEN THEN...WEATHER FORECAST MODELS ARE
CALLING FOR THE BRUNT OF RAINFALL TO MISS OUR AREA TO THE
SOUTHEAST...AND BELIEVE THE PASSAGE OF THIS SYSTEM WILL AMOUNT TO
SPOTTY SHOWERS FOR THE MOUNTAINS...AND PERHAPS THE PIEDMONT SOUTH OF
HIGHWAY 460. SUNDAY NIGHT LOWS WILL RANGE FROM THE UPPER 50S AND LOW
60S WEST...TO THE MID 60S EAST.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
AS OF 400 AM EDT SUNDAY...
A WEAK UPPER LOW AND ASSOCIATED TROPICAL MOISTURE ASSOCIATED WITH
FORMER TROPICAL SYSTEMS DANNY AND ERIKA...WILL BE LIFTING NORTHEAST
ACROSS THE REGION MONDAY ON THE WESTERN PERIPHERY OF A BUILDING
SUBTROPICAL RIDGE ACROSS THE WESTERN ATLANTIC. MODEST LOW-LEVEL
MOISTURE INCREASE IS INDICATED WITH PRECIPITABLE WATER VALUES
CREEPING INTO THE 1.5/1.6 RANGE ACROSS MUCH OF THE CWA. AT THE SAME
TIME...HOWEVER...THE UPPER TROUGH IS WEAKENING AND SHEARING OUT. ON
THE OTHER END OF THE CWA A DIFFUSE AND STALLING FRONT BOUNDARY WILL
BE LOCATED JUST TO OUR NORTH WITH THE ASSOCIATED UPPER AIR SUPPORT
HAVING LIFTED WELL NORTHEAST OF THIS REGION. DESPITE THESE WEAK
SYSTEMS...THE UNDERLYING THEME WILL BE A BROAD SUBTROPICAL RIDGE
BUILDING ACROSS MUCH OF THE EASTERN 2/3RDS OF THE U.S.
SUFFICIENT MOISTURE...INSTABILITY...AND DYNAMICS...GIVEN THE
FRONT TO THE NORTH AND UPPER TROUGH LIFTING ACROSS THE REGION...
SHOULD BE PRESENT MONDAY TO SUPPORT ISOLATED TO SCATTERED DIURNAL
CONVECTION...WITH A FEW SPRINKLES OR LIGHT SHOWERS EVEN POSSIBLE
DURING THE MORNING...TYPICAL FOR A POCKET OF REMNANT TROPICAL
MOISTURE DRIFTING ACROSS THE REGION. AM NOT CONCERNED ABOUT A HEAVY
RAIN THREAT GIVEN THE LACK OF ANY FOCUSING MECHANISM AND NOTING THAT
THE PLUME OF DEEP TROPICAL MOISTURE REMAINS GENERALLY OFF THE EAST
COAST. MODEL QPF IS VERY LACKLUSTER...GENERALLY 1/4 INCH AMOUNTS AT
BEST. THIS AGREES WELL WITH WPC.
FOR TUE-WED...THE MAIN STORY WILL BE THE BUILDING UPPER RIDGE. ANY
VESTIGE OF THE TROPICAL SYSTEMS...FRONTAL BOUNDARY...AND UPPER
TROUGH IS COMPLETELY GONE IN THIS TIME FRAME WITH 588DM OR GREATER
HEIGHTS ENCOMPASSING MOST OF THE U.S. SOUTH OF THE CANADIAN
BORDER...WEST TO THE ROCKIES. A VERY WEAK UPPER LOW TROUGH
WILL LINGER ACROSS THE WESTERN TN VALLEY INTO THE SOUTHERN
PLAINS. LINGERING TRAPPED TROPICAL MOISTURE AND DIFFERENTIAL HEATING
ACROSS THE MOUNTAINS WILL LIKELY BE SUFFICIENT EACH AFTERNOON TO
TRIGGER ISOLATED CONVECTION...BUT LITTLE TO SUPPORT MORE THAN 30
POPS AT THIS TIME. BY WED AFTERNOON...THE GFS AND ECMWF BOTH DEPICT
A POTENTIAL BACKDOOR FRONT SLIPPING INTO THE REGION FROM THE
NORTHEAST...WITH A SLIGHT INCREASE IN CONVECTION POSSIBLE ACROSS THE
NORTHERN AREAS AS A RESULT.
TEMPERATURES WILL BE ON THE INCREASE THROUGH THE PERIOD AS 850MB
TEMPS RISE FROM THE CURRENT LEVELS AROUND +14C TO +16C TOWARD +20C
DURING THE PERIOD. THIS WILL SUPPORT HIGHER MAX TEMPS...WITH SOME
AREAS ACROSS THE PIEDMONT APPROACHING 90 DEGREES...WITH 75 TO 80
MOUNTAINS AND 80S ELSEWHERE. MIN TEMPS WILL ALSO BE ON THE INCREASE
WITH HIGHER DEWPOINTS/RH/PWATS IN PLACE THROUGH THE PERIOD. OVERALL
MIN TEMPS WILL AVERAGE 10 DEGREES ABOVE NORMAL THROUGH THE PERIOD
WITH MAX TEMPS ABOUT 5 DEGREES ABOVE AVERAGE.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 415 AM EDT SUNDAY...
THE EXTENDED PERIODS CONTINUE TO BE LARGELY DOMINATED BY A BROAD
LATE SUMMER UPPER RIDGE ACROSS THE EASTERN HALF OF THE U.S.
INCREASING TROUGHING ALONG THE WEST COAST WILL ALLOW THE UPPER RIDGE
TO PUSH FURTHER EAST...QUICKLY ERASING ANY MIDWEEK EFFECTS OF A
BACKDOOR FRONT AND WEAK SHORTWAVE TRAVERSING THE NORTHEASTERN
PERIPHERY OF THE UPPER RIDGE. TROPICAL MOISTURE WILL LINGER ACROSS
THE REGION WITH NO CHANGE IN AIR MASS EXPECTED. ON THE OTHER
HAND...THERE IS SIMPLY NO SYNOPTIC/DYNAMIC TRIGGERING MECHANISM.
THIS LEAVES CONVECTION TO BE DRIVEN ENTIRELY BY DIFFERENTIAL DIURNAL
HEATING THROUGH THE END OF THE WORK WEEK.
TEMPERATURES ARE EXPECTED TO CONTINUE ABOVE NORMAL THROUGH THE
PERIOD WITH HIGHS 75 TO 80 MOUNTAINS AND 80S ELSEWHERE...NEAR 90
ACROSS THE PIEDMONT. MIN TEMPS WILL BE MORE SIGNIFICANTLY ABOVE
NORMAL WITH MAINLY 60S TO NEAR 70 PIEDMONT. THESE READINGS ARE 5 TO
10 DEGREES ABOVE NORMAL.
LOOKING AHEAD...SOME MODELS ARE ADVERTISING PERHAPS THE FIRST FALL
COLD FRONT INTO THE FOLLOWING WEEK...BUT ENTIRELY TOO FAR OUT TO
PUT ANY CREDIBILITY IN AT THIS POINT.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 745 AM EDT SUNDAY...
CLOUD COVER CONTINUES TO THICKEN AND GRADUALLY LOWER THIS MORNING
AS WEAK UPPER LEVEL DISTURBANCES APPROACH FROM THE SOUTH. CEILINGS
ARE VFR...RANGING IN HEIGHT FROM 8KFT TO 15KFT MOST LOCATIONS.
STILL A LITTLE PATCHY FOG REPORTED IN A FEW SPOTS...HOWEVER
EXPECT VISIBILITIES TO IMPROVE AFTER 14Z WITH DAYTIME HEATING.
FOR TODAY...EXPECT A GRADUAL INCREASE IN SHOWER ACTIVITY AS WEAK
DISTURBANCES PASS ACROSS THE AREA. WEATHER MODEL FORECAST
SOUNDINGS CONTINUE TO INDICATE THAT THE LOW LEVELS OF THE
ATMOSPHERE WILL REMAIN DRY...SUCH THAT CEILING BASES WILL FALL
INTO THE 4KFT TO 8KFT RANGE DURING LATE AFTERNOON...BUT WILL
REMAIN MOSTLY VFR. ANY REDUCTIONS IN VISIBILITIES WILL BE LIMITED
TO THOSE IN RAINFALL...WHICH SHOULD BE BRIEF DUE TO THE RATHER
SPOTTY NATURE OF THE SHOWER ACTIVITY. INSTABILITY APPEARS TO BE
VERY LIMITED...SO ANY THUNDERSTORMS WHICH DEVELOP SHOULD BE
ISOLATED AND SHORT LIVED.
A STRONGER UPPER LEVEL DISTURBANCE WILL APPROACH THE AREA LATE
SUNDAY EVENING...HOWEVER WEATHER MODELS APPEAR TO BE IN GOOD
AGREEMENT THAT THE MOST SIGNIFICANT RAINFALL WILL MISS THE AREA TO
THE SOUTHEAST. AS SUCH...EXPECT CONTINUED SPOTTY RAINFALL
OVERNIGHT...WITH MAINLY VFR CEILINGS. CLOUD COVER IS EXPECTED TO
KEEP REDEVELOPMENT OF FOG MINIMAL.
EXTENDED AVIATION DISCUSSION...
THE FORECAST AREA WILL THEN REMAIN IN A WEAKLY FORCED SYNOPTIC
ENVIRONMENT THROUGH MIDWEEK...WITH CHANCES FOR DIURNAL CONVECTION
MAINLY FROM THE BLUE RIDGE WEST...AND SOME MVFR/IFR FOG/STRATUS
DEVELOPMENT AT NIGHT...ESPECIALLY AT KBCB AND KLWB.
&&
.EQUIPMENT...
AS OF 700 AM EDT SUNDAY...
THE DEW POINT READING AT KJFZ...RICHLANDS VA AWOS...IS INCORRECT.
AT THIS TIME WE DO NOT KNOW WHEN THIS SENSOR WILL BE REPAIRED.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...NF
NEAR TERM...CF/NF
SHORT TERM...RAB
LONG TERM...AMS/RAB
AVIATION...NF/WP
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1031 AM CDT SUN AUG 30 2015
.UPDATE...WHILE VSBYS HAVE SHOWN IMPROVEMENT ALLOWING FOR DENSE
FOG ADVISORY TO EXPIRE...STRATUS DECK LINGERS ESP ACRS SE WI. RAP
SOUNDINGS APPEAR TO BE DRYING THINGS OUT TOO QUICKLY SO HAVE
BOOSTED SKY GRIDS AND TWEAKED TEMPS DOWN TO ACCOUNT FOR THESE
TRENDS. DUE TO INCREASING SSW WINDS OFF THE DECK TONIGHT DENSE
FOG MAY NOT BE AS MUCH OF AN ISSUE...BUT OVERALL PERSISTING LIGHT
WIND REGIME...LITTLE SURFACE LOW AND STILL PLENTY OF MOISTURE WILL
LEAD TO MORE FOG.
PC
&&
.AVIATION/18Z TAFS/...VSBL SATELLITE ANIMATION SHOWS PERSISTENT
STRATUS DECK NOT SHOWING MUCH SIGNS OF EROSION ACROSS SE WI AND
PORTIONS OF SC WI. LINGERING LIFR CIGS SHOULD LIFT SOME WITH TIME.
OVERALL EXPECTING A TREND TOWARDS MVFR CIGS WITH IFR CIGS HANGING
ON A BIT LONGER IN THE ERN CWA. RAP SOUNDINGS LOOK TOO AGGRESSIVE
IN CLEARING THINGS OUT SO STAYING MORE PESSIMISTIC ON OVERALL
CLOUD COVERAGE. MORE FOG/STRATUS EXPECTED TONIGHT WITH LIGHT WIND
REGIME AND LOW LEVEL MOISTURE. HOWEVER SLIGHTLY STRONGER WINDS OFF
THE DECK MAY LIMIT THE COVERAGE OF DENSE FOG.
PC
&&
.MARINE...A DENSE FOG ADVISORY IS IN EFFECT UNTIL 3 PM AS A RELATIVELY
WARM AND HUMID AIRMASS IS OVER THE COOLER WATERS OF LAKE MICHIGAN.
SOME FOG MAY CONTINUE TO PERSIST LATE THIS AFTERNOON AND TONIGHT.
THE DENSE FOG ADVISORY MAY NEED TO BE EXTENDED IF THERE IS ENOUGH
DENSE FOG PRESENT.
GEHRING
&&
.PREV DISCUSSION... /ISSUED 336 AM CDT SUN AUG 30 2015/
TODAY AND TONIGHT...FORECAST CONFIDENCE MEDIUM.
FORCING WITH MID LEVEL TROUGH AND CONVERGENCE ALONG INVERTED SURFACE
TROUGH FINALLY MOVED FAR ENOUGH TO THE SOUTHEAST LATE SATURDAY
EVENING TO TAKE ANY DRIZZLE/VERY LIGHT RAIN OUT OF SOUTHERN
WISCONSIN. MAINLY 3-5 MILE FOG HAS FORMED WITH LIGHT WINDS AND
ABUNDANT LOW-LEVEL MOISTURE AS SURFACE HIGH PRESSURE HAS BECOME
CENTERED OVER STATE.
HAVE ISSUED A DENSE FOG ADVISORY UNTIL 14Z FOR THE NORTHERN-MOST
COUNTIES WHERE 1/4 MILE VSBYS HAVE BECOME WIDESPREAD AFTER LOWER
CLOUD COVER THAT STILL LINGERS OVER THE REST OF THE AREA CLEARED
OUT. SOME LOCALLY DENSE FOG HAS FORMED...MAINLY IN THE LAKESHORE
COUNTIES AND THE WISCONSIN RIVER VALLEY. WILL CONTINUE TO MONITOR
THE REST OF THE FORECAST AREA FOR FURTHER DEVELOPMENT...THOUGH THE
CLOUD DECK IS PREVENTING ADDITIONAL COOLING THAT WOULD PRODUCE
ADDITIONAL WIDESPREAD DENSE FOG. WILL CONTINUE TO HANDLE THESE OTHER
LOCATIONS WITH SPS ISSUANCES FOR NOW AND WATCH FOR NEED FOR AN
EXPANSION OF THE NORTHERN ADVISORY.
IN SPITE OF DECENT 850 AND 925 MB TEMPERATURE ADVECTION AS MID-UPPER
LEVEL RIDGING BUILD IN...WARMING WILL BE LIMITED TODAY AS FORECAST
SOUNDINGS AND LOW-LEVEL RH FORECASTS INDICATE LOW CLOUDS WILL BE
SLOW TO BREAK UP AFTER FOG LIFTS. HAVE BACKED OFF HIGH TEMPERATURES
A FEW DEGREES...BUT DO EXPECT SOME SUNSHINE THIS AFTERNOON
HIGH SLIDES OFF TO THE SOUTHEAST BY THIS EVENING...WITH RESULTING
SOUTHWEST FLOW PROVIDING SOME MIXING...THOUGH DECOUPLING WITH
SHALLOW INVERSION WILL PROBABLY ALLOW FOR SOME AREAS OF FOG AGAIN
TONIGHT...THOUGH EXPECT ENOUGH TURBULENT MIXING TO PREVENT
WIDESPREAD DENSE FOG.
MONDAY THROUGH SATURDAY...FORECAST CONFIDENCE...MEDIUM
SURFACE HIGH PRESSURE AND UPPER RIDGING IS EXPECTED TO GENERALLY
REMAIN PARKED OVER THE GREAT LAKES THROUGH THIS UPCOMING WEEK.
THIS SETUP SHOULD PUT SOUTHERN WISCONSIN IN A PERSISTENT MILD AND
MOIST SOUTHERLY FLOW. MODELS ARE SHOWING A WEAK WAVE OR TWO COULD
BRING A FEW STORMS AT SOME POINT DURING THE WEEK...SO HAVE SOME
LOW POPS IN THERE. NOT A LOT OF CONFIDENCE IN POPS DURING ANY ONE
PERIOD. SHOULD BE DRY FOR MUCH OF THE TIME.
MAIN STORY THIS WEEK WILL BE TEMPS WARMING TO ABOVE NORMAL
VALUES. HAVE BUMPED TEMPS UP ABOVE CONSENSUS OF MODELS AS 925 MB
TEMPS AROUND 25C SUGGEST HIGHS IN AT LEAST THE UPPER 80S TO AROUND
90 MOST DAYS. IT WILL PROBABLY BE A BIT COOLER NEAR LAKE MICHIGAN
AT TIMES WHEN SOUTH TO SOUTHWEST WINDS ARE NOT STRONG ENOUGH TO
KEEP THE LAKE BREEZE OFFSHORE.
AVIATION/12Z TAFS/...WILL SEE MVFR/IFR FOG AND CIGS CONTINUE INTO
THE MID TO LATE MORNING HOURS WITH AND ABUNDANT LOW LEVEL MOISTURE
AND HIGH PRESSURE CENTERED OVER STATE BRINGING WEAK FLOW. WEAK WAA
AND SOME MIXING WILL BRING VSBYS UP AND EVENTUALLY SCATTER OUT THE
CLOUDS THIS AFTERNOON. WILL SEE THE POTENTIAL FOR MVFR FOG...WITH
SOME IFR VSBYS TONIGHT...THOUGH 10 KNOT PLUS WINDS JUST OFF THE
SURFACE SHOULD PROVIDE ENOUGH MIXING TO PREVENT WIDESPREAD LOW
VSBYS.
MARINE...LIGHT WINDS WITH HIGH PRESSURE CENTERED OVER REGION AND A
MOIST AIRMASS REMAINING IN PLACE WILL KEEP A DENSE FOG ADVISORY
UNTIL 10 AM TODAY.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...DENSE FOG ADVISORY UNTIL 3 PM CDT THIS AFTERNOON FOR LMZ643>646.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...REM
MONDAY THROUGH SATURDAY...DDV
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
341 AM CDT SUN AUG 30 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 341 AM CDT SUN AUG 30 2015
MOST IMMEDIATE CONCERN IS PATCHY DENSE FOG EARLY THIS MORNING.
BECAUSE NOT ALL LOW CLOUD FROM YESTERDAY DISSIPATED AND THE FACT
THAT 0.5 KM SOUTHWEST WINDS ARE INCREASING FROM NOW UNTIL
SUNRISE...WIDESPREAD DENSE FOG IS IN QUESTION. THERE HAVE BEEN
SOME SITES ACROSS THE REGION THAT HAVE REPORTED ONE-HALF MILE OR
LESS IN FOG...BUT NOT CONSISTENTLY AS VISIBILITY GOES UP AND DOWN
OVER RELATIVELY SHORT PERIODS. FOR NOW...WILL COVER FOG THREAT
WITH A SPS...BUT MONITOR CAREFULLY FOR MORE WIDESPREAD PERSISTENT
LOW VISIBILITY THAT COULD NECESSITATE AN ADVISORY.
WHETHER STRATUS OF FOG...MOST AREAS SHOULD WAKE UP TO GRAY/FOGGY
SKIES. HOWEVER...LOW-LEVEL MOISTURE SHOULD BEGIN TO MIX OUT AFTER
SUNRISE AS BOUNDARY LAYER DEEPENS TO BETWEEN 1500 AND 2000 FT BY
MIDDAY. SHOULD FINALLY BEGIN TO SEE A FAIR AMOUNT OF SUN BY EARLY
TO MID AFTERNOON. WITH A SLOW START TO WARMING FOR THE DAY...
DROPPED TEMPERATURES A FEW DEGREES WITH HIGHS NOW EXPECTED IN THE
MID TO UPPER 70S. FOR AREAS THAT SEE A BIT MORE SUN...HIGHS MAY
WARM INTO THE LOWER 80S.
EXPECT MOSTLY CLEAR SKIES TONIGHT WITH LIGHT SOUTHERLY WINDS. WILL
KEEP PATCHY VALLEY/BOG FOG MENTION...BUT ITS OCCURRENCE IS A BIT
LESS CERTAIN. MODEL SOUNDINGS SHOWING NEAR SURFACE SATURATION...
BUT ALSO 15 TO 20 KTS IMMEDIATELY ABOVE THE NOCTURNAL INVERSION.
THIS SET-UP MAY BE MORE FAVORABLE FOR LOW STRATUS THAN FOG...BUT
SOMETHING TO WATCH. LOWS TONIGHT WILL DROP INTO THE 60S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 341 AM CDT SUN AUG 30 2015
MONDAY THROUGH WEDNESDAY...500 HPA RIDGE MOVES INTO THE EASTERN
CONUS...ALTHOUGH PERHAPS A BIT FLATTER THAN PREVIOUSLY FORECAST
GIVEN WEAK SHORT-WAVES MOVING THROUGH SOUTHWEST FLOW ALOFT. MAIN
IMPACT WILL BE WARMING TEMPERATURES WITH DAILY HIGHS IN THE 80S...
ALTHOUGH SOME VALLEY LOCATIONS COULD APPROACH 90 DEGREES GIVEN
FAVORABLE SOUTH-SOUTHWEST SURFACE WIND. RIDGE AXIS RETROGRADES
BACK ACROSS THE SOUTHERN PLAINS FOR LATE IN THE WEEK...RESULTING
IN THUR/FRI/SAT POSSIBLY BEING THE WARMEST DAYS OF THE WEEK WITH
MANY LOCATIONS INTO THE UPPER 80S...PERHAPS 90 DEGREES.
WILL KEEP PERIODIC 20-30 POPS THROUGH THE WEEK...ALTHOUGH THINK
DRY CONDITIONS WILL BE THE RULE SINCE AXIS OF MAXIMUM MID-LEVEL
MOISTURE TRANSPORT REMAINS MAINLY WEST OF THE FORECAST AREA AND
DEEP LAYER SHEAR IS WEAK. BEST CHANCE FOR MORE WIDESPREAD SHOWERS
AND THUNDERSTORMS HOLDS OFF UNTIL LATE SATURDAY INTO SUNDAY AS
EASTERN PACIFIC TROUGH/COLD FRONT FINALLY PUSH FAR ENOUGH EAST TO
IMPACT THE UPPER MS RIVER VALLEY. WILL INTRODUCE HIGH END CHANCE
POPS FOR THIS PERIOD. WITH CLOUDS/POSSIBLE RAIN AND APPROACHING
COLD FRONT...COULD SEE TEMPERATURES BEGIN TO RETREAT AS EARLY AS
NEXT SUNDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1130 PM CDT SAT AUG 29 2015
VERY CHALLENGING FORECAST.
FOG...STRATUS...OR BOTH REMAINS THE QUESTION AND LATEST MODELS RUNS
AND TRENDS AREN/T GIVING MUCH CONFIDENCE ONE WAY OR THE OTHER. THAT
SAID - THE IMPACTS ON AVIATION COULD BE THE SAME AS FLIGHT
CATEGORIES FROM FOG OR LOW STRATUS COULD BE THE SAME.
LOW STRATUS HAS BEEN RELUCTANT TO EXIT THE AREA AT LATE
EVENING...SLOWING DOWN/STOPPING. THERE ARE EVEN SOME HINTS OF
NORTHWARD DEVELOPMENT OVER NORTHERN IA. RAP MODEL SUGGEST THIS WILL
OCCUR IN EARNEST...WITH LOW CIGS SPREADING OVER SOUTHERN MN
OVERNIGHT. KLSE WOULD HOLD STEADY OR DROP A BIT IN HEIGHTS...BUT
LIKELY STAY IFR.
IF THE STRATUS DOES NOT ADVANCE INTO KRST...FOG IS THE LIKELY
OUTCOME...AND SUB 1SM IS A POSSIBILITY. SOME LOCATIONS ACROSS
SOUTHERN MN/NORTHERN IA ALREADY HAVE VSBY RESTRICTIONS. IF THE
STRATUS HOLDS AT KLSE...THE IMPACT ON VSBYS WILL NOT BE AS EXTREME AS
FIRST FORECAST.
CONFIDENCE IS HIGH IN CIGS AND/OR FOG IMPACTS AT KRST/KLSE OVERNIGHT
THROUGH MOST OF SUN MORNING. WHICH ONE IS MORE DOMINANT IS WHERE THE
CONFIDENCE IS SHAKY. GOING TO STAY THE COURSE AS A RESULT...HOLDING
WITH THE PREVIOUS FORECAST FOR THE MOST PART. EXPECT UPDATES
OVERNIGHT AS CONFIDENCE INCREASES IN THE MORE LIKELY OUTCOME.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...ROGERS
LONG TERM...ROGERS
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1130 PM CDT SAT AUG 29 2015
.SHORT TERM...(TONIGHT THRU SUNDAY NIGHT)
ISSUED AT 237 PM CDT SAT AUG 29 2015
MAIN FCST CONCERNS THIS PERIOD...LATE NIGHT/EARLY MORNING
RADIATIONAL FOG POTENTIAL...TEMPERATURES.
18Z DATA ANALYSIS HAD LOW PRESSURE OVER SOUTHEAST IA/NORTHWEST IL
AND OVER CENTRAL SASKAT. WEAK HIGH PRESSURE EXTENDED FROM EASTERN
NEB TO NORTHERN WI/LOWER MI BETWEEN THEM. WV IMAGERY SHOWED
SHORTWAVE ENERGY AND A SECONDARY TROUGH AXIS DROPPING ACROSS IA AND
SOUTHEAST WI...WITH SUBSIDENCE/RISING HGTS SPREADING ACROSS MN/WI
BEHIND IT. SUBSIDENCE WAS STRENGTHENING AN INVERSION NEAR 925MB...
HELPING TO TRAP LOWER LEVEL MOISTURE/CLOUDS ACROSS MUCH OF THE
SOUTHEAST HALF OF THE UPPER MIDWEST. CLOUDS SLOWLY ERODING ACROSS
SOUTHERN MN/CENTRAL WI WITH DIURNAL WARMING/MIXING AND SOME WEAK SFC-
925MB ANTICYCLONIC FLOW. STUBBORN CLOUDS HOLDING TEMPS DOWN WITH
WARMEST TEMPS ACROSS THE REGION ONCE AGAIN OVER THE NORTHWEST HALF
OF MN WITH SOME SUNSHINE.
NO BIG PROBLEMS NOTED WITH 29.12Z MODEL INITIALIZATIONS. SOLUTIONS
TRENDING TOWARD A TIGHTER CONSENSUS AS HGTS RISE/RIDGING ALOFT
BUILDS INTO THE UPPER MIDWEST TONIGHT/SUN...THEN AS HGTS FALL A BIT
AHEAD OF A STRONGER SHORTWAVE TROUGH MOVING INTO WESTERN ND BY 12Z
MON. TREND IS TOWARD A COMPROMISE OF THE EARLY RUNS WITH THE RIDGING
OVER THE REGION AND TOWARD STRONGER OF EARLIER RUNS ON THE SHORTWAVE
INTO WESTERN ND LATE SUN NIGHT. WITH THE TIGHTER CONSENSUS...SHORT
TERM FCST CONFIDENCE IS GENERALLY GOOD THIS CYCLE.
FOR THE SHORT TERM...LOWER CLOUDS/MOISTURE TRAPPED IN WEAK FLOW
UNDER A MDT/STRONG INVERSION NEAR 925MB PROVING PROBLEMATIC.
STRENGTHENING THE INVERSION ABOVE 925MB MAKING THE LOW CLOUD
LAYER MORE RESISTANT TO MIXING/EROSION. DIURNAL WARMING/MIXING
WAS WORKING ON IT THIS AFTERNOON...THOUGH MUCH SLOWER THAN EARLIER
EXPECTED. CLOUD COVER HAS BEEN INCREASED OVER MUCH OF THE FCST
AREA THRU THE EVENING...ESPECIALLY OVER THE SOUTHEAST HALF.
REMAINED OPTIMISTIC WITH A DECREASE OF CLOUDS THRU THE LATE
EVENING...EVEN AS WINDS BECOMING QUITE LIGHT /LESS THAN 5 TO
10KTS/ THRU 700MB BY/AFTER MIDNIGHT. CLOUDS AND HOW LONG THEY STAY
TONIGHT WILL HAVE IMPACTS ON THE RADIATIONAL FOG DEVELOPMENT.
STRONG SIGNAL AMONG ALL MODELS FOR WIDESPREAD FOG LATE TONIGHT
INTO SUN MORNING. EARLIER CLEARING WOULD ALLOW FOR MORE
WIDESPREAD FOG...WITH GREATER POTENTIAL/COVERAGE OF DENSE FOG
BETWEEN 09-14Z SUN. SLOWER CLEARING/LINGERING LOW CLOUDS TONIGHT
WOULD KEEP THE FOG MORE PATCHY WITH THE FOG /SOME DENSE/ MAINLY IN
THE RIVER VALLEYS. WILL LEAVE THE FOG GRIDS TONIGHT AS IS WITH
AREAS/WIDESPREAD IN THE VALLEYS/MORE FOG PRONE AREAS AND PATCHY
ELSEWHERE. HOWEVER DID EXPAND AT LEAST SOME PATCHY FOG MENTION IN
TIME FROM 05Z-15Z. DUE TO THE STRENGTH OF THE INVERSION AND
SATURATION BELOW IT...WILL HAVE TO WATCH FOR SOME OF THE FOG
PERSISTING PAST 15Z. GIVEN UNCERTAINTIES WITH LOW CLOUDS LATE
THIS AFTERNOON/EVENING...WILL NOT ISSUE A DENSE FOG ADVISORY AT
THIS TIME BUT ONE MAY YET BE NEEDED CENTERED AROUND 12Z SUN.
SFC-850MB RIDGE AXIS MOVES A BIT SOUTH OF THE AREA FOR SUN
AFTERNOON/NIGHT...WITH SFC-850MB WINDS MORE SOUTHWEST IN THE
5-15KT RANGE FOR MORE LOWER LEVEL MIXING. PLENTY OF DRY AIR ABOVE
THE INVERSION WITH DIURNAL WARMING/MIXING LOOKING GIVE US A SUNNY
SUNDAY AFTERNOON. MODEL SOUNDINGS INDICATING 15-20KTS ABOVE THE
NOCTURNAL INVERSION SUN NIGHT...WITH ANY RADIATIONAL VALLEY FOG
LOOKING MUCH LESS WIDESPREAD. GIVEN THE MOIST BOUNDARY LAYER FROM
RECENT RAINS...DID ADD A PATCHY FOG MENTION TO THE VALLEYS AND
MORE FOG PRONE AREAS BETWEEN 09-14Z MON. 925MB TEMPS IN THE 21C-
24C RANGE SUN AFTERNOON. WITH SOME SUNSHINE AND THE MIXING...HIGHS
SUNDAY TRENDING NEAR TO A BIT ABOVE NORMAL. USED A BLEND OF THE
GUIDANCE LOWS/HIGHS FOR TONIGHT THRU SUN NIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 237 PM CDT SAT AUG 29 2015
FOR MONDAY THRU TUESDAY NIGHT...
MAIN FCST CONCERNS THIS PERIOD...ABOVE NORMAL TEMPERATURES...SMALL
SHRA/TSRA CHANCE TUE NIGHT.
29.12Z MODELS IN GOOD AGREEMENT AT THE ND SHORTWAVE LIFTS INTO
NORTHWEST ONT MON...PUSHING THE MID LEVEL RIDGE AXIS INTO MI/EASTERN
ONT. DECENT AGREEMENT THEN FOR BROAD SOUTHWEST FLOW ALOFT OVER THE
NORTH CENTRAL CONUS MON NIGHT INTO TUE NIGHT. IMPROVING CONSENSUS
FOR A SHORTWAVE TO RIPPLE NORTHEAST OUT OF THE SOUTHERN PORTION OF
THE WESTERN CONUS TROUGHING AND TOWARD/INTO THE UPPER MIDWEST TUE
NIGHT. TREND WITH THE APPROACHING SHORTWAVE TUE NIGHT IS TOWARD
STRONGER OF THE EARLIER RUNS.
PERSISTENT WESTERN TROUGHING KEEPS LEE TROUGHING OVER THE PLAINS
THRU THIS PERIOD...WITH THE REGION IN THE BROAD SOUTHWEST LOW LEVEL
FLOW AHEAD OF IT. LOWER LEVELS CONTINUE TO WARM THIS PERIOD AND WITH
A CONNECTION TO THE GULF MEX MOISTURE CONTINUES TO INCREASE AS WELL.
THIS PERIOD TO FEEL RATHER SUMMERY AS HIGHS REACH INTO THE MID 80S
TO AROUND 90 AND DEW POINTS RISE INTO THE MID/UPPER 60S. THIS
AIRMASS WILL BECOME UNSTABLE...ESPECIALLY DURING THE AFTERNOONS WITH
AS MUCH AS 1500-2500 J/KG MUCAPE. LITTLE IN THE WAY OF TRIGGERS FOR
CONVECTION SEEN OVER/CLOSE TO THE AREA MON THRU TUE AS THE ND
SHORTWAVE AND ITS ATTENDANT LOWER LEVEL TROUGH SHEAR NORTHEAST INTO
CAN. POTENTIAL FOR AS MUCH AS 100-150 J/KG CIN OVER THE AREA BOTH
MON/TUE AFTERNOONS AS WELL. WILL LEAVE MON-TUE DRY. APPROACHING
SHORTWAVE TUE NIGHT SPREADS SOME INCREASE OF LOWER LEVEL MOISTURE
TRANSPORT INTO THE AREA AND SOME REDUCTION OF THE CAPPING WITH DUE
TO WEAK 700-500MB COOLING. SMALL SHRA/TSRA CHANCE ACROSS MAINLY THE
NORTHWEST HALF OF THE FCST AREA TUE NIGHT OKAY FOR NOW. 925MB TEMPS
MON/TUE PROGGED IN THE 24C-27C RANGE...SUPPORTING HIGHS IN THE MID
80S TO NEAR 90...10F-15F ABOVE NORMAL. TRENDED TOWARD WARMER OF
GUIDANCE HIGHS MON/TUE WHILE FAVORING A BLEND OF THE GUIDANCE LOWS
MON/TUE NIGHTS.
FOR WEDNESDAY THRU SATURDAY...DAYS 4 TO 7...
MAIN FCST CONCERNS THIS PERIOD...SMALL SHRA/TSRA ALMOST ANY
PERIOD...ABOVE NORMAL TEMPERATURES.
29.00Z/2.12Z MEDIUM RANGE MODELS SHOW A GOOD CONSENSUS FOR RATHER
STRONG EASTERN NOAM RIDGING/WESTERN NOAM TROUGHING WED. IMPROVING
AGREEMENT FOR THE TUE NIGHT SHORTWAVE ENERGY TO MOVE ACROSS THE
UPPER MIDWEST WED. DECENT AGREEMENT FOR THE NOAM FLOW TO AMPLIFY
THU/FRI AS THE WEST COAST TROUGH DEEPENS AND RIDGING STRENGTHENS
OVER THE MID/UPPER MS VALLEY. TREND THU/FRI FAVORS STRONGER OF
EARLIER RUNS WITH THE WESTERN NOAM TROUGHING AND THE LESS ROBUST
WITH THE MID CONUS RIDGING. DECENT AGREEMENT FOR THE PATTERN TO
THEN SLOWLY PROGRESS SAT WITH THE WESTERN TROUGH MOVING INLAND AND
THE UPPER RIDGE AXIS SHIFTING EAST OF THE REGION. DAY 4-7
CONFIDENCE REMAINS GOOD FOR ABOVE NORMAL TEMPERATURES BUT AVERAGE
FOR THE SHRA/TSRA CHANCES.
UNDER THE RIDGING ALOFT...A WARM/MOIST LOWER LEVEL AIRMASS /PW
VALUES AND 850MB TEMPS OF 1 TO 2 STD DEVIATIONS ABOVE NORMAL/ IS
OVER THE REGION DURING THE DAY 4-7 PERIOD. SOME 1K-2K J/KG MUCAPE
PROGGED OVER THE AREA IN THIS AIRMASS DURING THE AFTERNOONS.
QUESTIONS MOST DAYS WILL BE TIMING OF THE SHORTWAVES THRU THE FLOW
AND HOW MUCH CAPPING/CIN OVER THE AREA. WITH THE SIGNAL FOR A
TRACKABLE SHORTWAVE TO MOVE ACROSS THE AREA WED...SMALL SHRA/TSRA
CHANCES THIS DAY REASONABLE FOR NOW. AREA REMAINS NEAR THE WEST/
NORTH PERIMETER OF THE MID LEVEL RIDGE THU THRU SAT...WITH MORE WEAK
AND POORLY TIMED SHORTWAVES LOOKING TO RIPPLE UP AND OVER THE WEST
SIDE OF THE RIDGING. CAPPING FURTHER UNDER THE RIDGE AXIS MAY KEEP
THE AREA PROTECTED FROM SHRA/TSRA CHANCES THU/FRI. WITH THE RIDGE
AXIS SHIFTING EAST A BIT FOR SAT...CAPPING MAY BE LESS WITH
POTENTIAL FOR A WEAK SHORTWAVE OR 2 TO SPREAD A SHRA/TSRA CHANCE
INTO THE AREA. GIVEN LESSER CONFIDENCE IN THE SMALLER SHORTWAVES AND
MESO-SCALE DETAILS IN THE WED-SAT PERIOD...WITH STAY WITH THE
MODEL/ENSEMBLE CONSENSUS SHRA/TSRA CHANCES FOR DAYS 4-7. LOWER LEVEL
TEMPERATURE PROFILES CONTINUE TO SUPPORT TEMPS AROUND 10F TO 15F
ABOVE NORMAL NEXT WEEK. MODEL/ENSEMBLE CONSENSUS HIGHS/LOWS FOR WED-
SAT GENERALLY LOOK GOOD BUT DID RAISE HIGHS IN THE MS/WI RIVER
VALLEYS A COUPLE DEGREES ABOVE THE CONSENSUS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1130 PM CDT SAT AUG 29 2015
VERY CHALLENGING FORECAST.
FOG...STRATUS...OR BOTH REMAINS THE QUESTION AND LATEST MODELS RUNS
AND TRENDS AREN/T GIVING MUCH CONFIDENCE ONE WAY OR THE OTHER. THAT
SAID - THE IMPACTS ON AVIATION COULD BE THE SAME AS FLIGHT
CATEGORIES FROM FOG OR LOW STRATUS COULD BE THE SAME.
LOW STRATUS HAS BEEN RELUCTANT TO EXIT THE AREA AT LATE
EVENING...SLOWING DOWN/STOPPING. THERE ARE EVEN SOME HINTS OF
NORTHWARD DEVELOPMENT OVER NORTHERN IA. RAP MODEL SUGGEST THIS WILL
OCCUR IN EARNEST...WITH LOW CIGS SPREADING OVER SOUTHERN MN
OVERNIGHT. KLSE WOULD HOLD STEADY OR DROP A BIT IN HEIGHTS...BUT
LIKELY STAY IFR.
IF THE STRATUS DOES NOT ADVANCE INTO KRST...FOG IS THE LIKELY
OUTCOME...AND SUB 1SM IS A POSSIBILITY. SOME LOCATIONS ACROSS
SOUTHERN MN/NORTHERN IA ALREADY HAVE VSBY RESTRICTIONS. IF THE
STRATUS HOLDS AT KLSE...THE IMPACT ON VSBYS WILL NOT BE AS EXTREME AS
FIRST FORECAST.
CONFIDENCE IS HIGH IN CIGS AND/OR FOG IMPACTS AT KRST/KLSE OVERNIGHT
THROUGH MOST OF SUN MORNING. WHICH ONE IS MORE DOMINANT IS WHERE THE
CONFIDENCE IS SHAKY. GOING TO STAY THE COURSE AS A RESULT...HOLDING
WITH THE PREVIOUS FORECAST FOR THE MOST PART. EXPECT UPDATES
OVERNIGHT AS CONFIDENCE INCREASES IN THE MORE LIKELY OUTCOME.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RRS
LONG TERM....RRS
AVIATION.....RIECK
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.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
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.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
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.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
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.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
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 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
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...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
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
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 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 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
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
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 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 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 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
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 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 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 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 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 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 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 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 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 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.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...INIGUEZ/MP
AVIATION...MP
FIRE WEATHER...MP
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 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 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 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 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...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
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 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 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 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