Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/07/15
AREA FORECAST DISCUSSION
NWS TUCSON AZ
955 AM MST SAT SEP 5 2015
.SYNOPSIS...EXPECT SCATTERED SHOWERS THROUGH TONIGHT. HOWEVER...ANY
THUNDERSTORMS WILL BE QUITE LIMITED INTO TONIGHT. SCATTERED SHOWERS
AND THUNDERSTORMS WILL THEN OCCUR SUNDAY THROUGH TUESDAY. A SLIGHT
CHANCE OF THUNDERSTORMS WILL PREVAIL WEDNESDAY THROUGH FRIDAY...
ESPECIALLY EAST OF TUCSON. BELOW NORMAL TEMPERATURES WILL OCCUR
TODAY FOLLOWED BY A WARMING TREND STARTING SUNDAY AND
CONTINUING DURING THE UPCOMING WEEK.
&&
.DISCUSSION...SCATTERED TO NUMEROUS SHOWERS PRODUCING MOSTLY LIGHT
RAINFALL WAS OCCURRING ACROSS PORTIONS OF SE ARIZONA AT THIS TIME.
THE BULK OF THESE SHOWERS WAS ACROSS SE PINAL COUNTY...CENTRAL/ERN
PIMA COUNTY SWD INTO SANTA CRUZ COUNTY. MOST RAINFALL AMOUNTS SINCE
7 AM MST HAVE BEEN LESS THAN ONE TENTH OF AN INCH. HOWEVER...A FEW
GAUGES IN THE MOUNTAINS HAVE RECORDED UP TO ONE QUARTER ON AN INCH.
OTHERWISE...IR/VISIBLE SATELLITE IMAGERY DEPICTED CLOUDY SKIES
ACROSS MUCH OF SE ARIZONA. HOWEVER...MOSTLY SUNNY SKIES PREVAILED
ACROSS FAR WRN PIMA COUNTY. AMPLE MOISTURE WAS IN PLACE ACROSS THIS
FORECAST AREA...WITH 05/12Z KTWC SOUNDING TOTAL PRECIP WATER VALUE
OF 1.64 INCHES. THE SOUNDING DEPICTED A MARGINALLY UNSTABLE
ENVIRONMENT...WITH LIFTED INDEX VALUES RANGING FROM MINUS 1 TO MINUS
3 DEPENDING UPON THE LIFTING METHOD. 05/12Z UPPER AIR PLOTS DEPICTED
UPPER TROUGH OVER THE PACIFIC NW WITH HIGH PRESSURE ALOFT CENTERED
OVER WEST CENTRAL TEXAS. LIGHT TO MODERATE SWLY FLOW ALOFT PREVAILED
ACROSS SE ARIZONA.
BASED ON RADAR/SATELLITE TRENDS AND SEVERAL HRRR SOLUTIONS...APPEARS
THAT THE ONGOING AREA OF SHOWERS WILL GRADUALLY SHIFT EASTWARD
DURING THE NEXT SEVERAL HOURS. HAVE NOTED THAT THE 05/12Z UNIV OF AZ
WRF-NAM DEPICTS SOME STRONGER PRECIP ECHOES SUGGESTING THE POTENTIAL
FOR THUNDERSTORMS MAY OCCUR THIS AFTERNOON ACROSS WRN SECTIONS...AND
ACROSS WRN/CENTRAL COCHISE COUNTY. BELIEVE THAT THERE WILL NEED TO
BE AT LEAST SOME CLEARING FOR ANY THUNDERSTORMS TO EVENTUALLY OCCUR.
THERE ARE SOME INDICATIONS AS PER VISIBLE SATELLITE IMAGERY
SUGGESTING BRIEF CLEARING MAY OCCUR DURING THE NEXT 1-2 HOURS SE OF
TUCSON.
AT ANY RATE...WILL MAINTAIN SCATTERED SHOWERS AND A SLIGHT CHANCE OF
THUNDERSTORMS INTO THIS EVENING. WILL LIKELY MAKE SOME MINOR
DOWNWARD ADJUSTMENTS TO HIGH TEMPS FOR TODAY...ESPECIALLY FOR
LOCALES WHERE SHOWERS ARE ONGOING.
PLEASE REFER TO THE ADDITIONAL SECTIONS FOR FURTHER DETAIL.
&&
.AVIATION...VALID THRU 06/18Z.
SCATTERED TO NUMEROUS -SHRA WILL OCCUR INTO THIS EVENING. THERE WILL
ALSO BE A SLIGHT CHANCE OF -TSRA...PARTICULARLY THIS AFTERNOON AND
EVENING. ISOLATED TO SCATTERED -SHRA AND A SLIGHT CHANCE OF -TSRA
WILL THEN OCCUR LATE TONIGHT INTO SUNDAY MORNING. OTHERWISE...
BROKEN TO OVERCAST CLOUDS RANGING FROM 8-12K FT AGL AND SURFACE WIND
MAINLY LESS THAN 10 KTS WILL PREVAIL INTO SUNDAY MORNING. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...SCATTERED SHOWERS AND A SLIGHT CHANCE OF
THUNDERSTORMS WILL OCCUR INTO TONIGHT. SCATTERED SHOWERS AND
THUNDERSTORMS WILL THEN PREVAIL SUNDAY THROUGH TUESDAY. ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS ARE FORECAST TO OCCUR WEDNESDAY
THROUGH FRIDAY. THE BULK OF THESE SHOWERS AND THUNDERSTORMS DURING
THE LATTER PART OF THE WEEK SHOULD BE EAST OF TUCSON.
&&
.PREVIOUS DISCUSSION /325 AM MST/...MOISTURE REMAINING IN PLACE ON
SUNDAY FOR A CHANCE OF SHOWERS AND THUNDERSTORMS WITH HIGHS SLIGHTLY
WARMER THAN TODAY.
MONDAY AND TUESDAY...ANOTHER TROPICAL SYSTEM IS FORECAST TO PASS
WEST OF SRN BAJA. FOR OUT NECK OF THE CACTI...FLOW ALOFT WILL BECOME
MORE WESTERLY...ESPECIALLY ON TUESDAY. STILL ENOUGH MOISTURE AROUND
FOR A SLIGHT CHANCE OF STORMS BOTH DAYS.
WEDNESDAY AND THURSDAY...THE TRACK OF ABOVE MENTIONED TROPICAL
SYSTEM WILL BE THE DRIVING FACTOR FOR THESE TWO DAYS. EC/CANADIAN
HAS TRACK CLOSER/FURTHER N OFF BAJA COAST VERSUS GFS. FOR NOW WILL
MAINTAIN LOW GRADE MONSOON FORECAST.
HIGHS WILL GRADUALLY WARM TO NEAR NORMAL LEVEL BY EARLY NEXT WEEK.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
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FRANCIS
AREA FORECAST DISCUSSION
NWS TUCSON AZ
320 AM MST SAT SEP 5 2015
.SYNOPSIS...A MOIST ATMOSPHERE WILL REMAIN IN PLACE THROUGH THIS
WEEKEND...WITH ISOLATED TO SCATTERED MAINLY AFTERNOON AND EVENING
SHOWERS AND THUNDERSTORMS THROUGH SUNDAY. A GRADUALLY REDUCTION IN
AREAL COVERAGE OF STORMS WILL OCCUR EARLY NEXT WEEK. BELOW NORMAL
DAYTIME TEMPERATURES WILL PREVAIL THROUGH THIS WEEKEND...WITH HIGH
TEMPERATURES RETURNING CLOSE TO SEASONAL NORMALS BY THE MIDDLE OF
NEXT WEEK.
&&
.DISCUSSION...MOSTLY CLOUDY CONDITIONS PREVAILED ACROSS THE AREA
THIS MORNING WITH ISOLATED LIGHT SHOWERS OCCURRING. QPF VALUES
RATHER LIGHT...LESS THAN 0.05". LATEST SATELLITE IMAGERY SHOWED THAT
THE MID LEVEL CIRCULATION FROM WEAKENING TS KEVIN HAS BROKEN AWAY
FROM THE LOW LEVELS AND IS BEING LIFTED NE ACROSS CENTRAL BAJA WITH
EYES ON SE AZ. LATEST RUNS OF THE HRRR AND RUC13 INCREASE AREAL
COVERAGE OF LIGHT SHOWERS LATER THIS MORNING INTO THIS AFTERNOON.
WITH THAT IN MIND MADE SOME SLIGHT ADJUSTMENTS TO THE FORECAST.
EMBEDDED AREAS OF THUNDER WILL ALSO OCCUR LATER TODAY. HIGHS TODAY
WELL BELOW NORMAL.
MOISTURE REMAINING IN PLACE ON SUNDAY FOR A CHANCE OF SHOWERS AND
THUNDERSTORMS WITH HIGHS SLIGHTLY WARMER THAN TODAY.
MONDAY AND TUESDAY...ANOTHER TROPICAL SYSTEM IS FORECAST TO PASS
WEST OF SRN BAJA. FOR OUT NECK OF THE CACTI...FLOW ALOFT WILL
BECOME MORE WESTERLY...ESPECIALLY ON TUESDAY. STILL ENOUGH MOISTURE
AROUND FOR A SLIGHT CHANCE OF STORMS BOTH DAYS.
WEDNESDAY AND THURSDAY...THE TRACK OF ABOVE MENTIONED TROPICAL
SYSTEM WILL BE THE DRIVING FACTOR FOR THESE TWO DAYS. EC/CANADIAN
HAS TRACK CLOSER/FURTHER N OFF BAJA COAST VERSUS GFS. FOR NOW WILL
MAINTAIN LOW GRADE MONSOON FORECAST.
HIGHS WILL GRADUALLY WARM TO NEAR NORMAL LEVEL BY EARLY NEXT WEEK.
&&
.AVIATION...VALID THRU 06/12Z.
BKN CLOUDS AT 9-12 KFT AGL. ISOLD -SHRA THIS AM...MAINLY FROM KTUS S
AND E...WILL BECOME SCTD AREA WIDE AFTER 05/20Z WITH ISOLD EMBDD TS.
BRIEF MVFR CONDITIONS POSSIBLE IN AND AROUND THE STRONGEST STORMS.
OUTSIDE OF THUNDERSTORM WIND GUSTS...SURFACE WINDS WILL GENERALLY BE
LESS THAN 10 KTS AND MAINTAIN A MORE SOUTHERLY COMPONENT THAN USUAL
DURING THE AFTERNOON. AVIATION DISCUSSION NOT UPDATED FOR TAF
AMENDMENTS.
&&
.FIRE WEATHER...SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THROUGH
THIS HOLIDAY WEEKEND INTO EARLY NEXT WEEK. WINDS WILL FAVOR A
SOUTHERLY DIRECTION...BUT WILL BE LIGHT ENOUGH TO SEE STRONG TERRAIN
INFLUENCES.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS TUCSON AZ
919 PM MST FRI SEP 4 2015
.SYNOPSIS...A MOIST ATMOSPHERE WILL REMAIN IN PLACE THROUGH THIS
WEEKEND...WITH ISOLATED TO SCATTERED MAINLY AFTERNOON AND EVENING
SHOWERS AND THUNDERSTORMS THROUGH SUNDAY. A GRADUALLY REDUCTION IN
AREAL COVERAGE OF STORMS WILL OCCUR EARLY NEXT WEEK. BELOW NORMAL
DAYTIME TEMPERATURES WILL PREVAIL THROUGH THIS WEEKEND...WITH HIGH
TEMPERATURES RETURNING CLOSE TO SEASONAL NORMALS BY THE MIDDLE OF
NEXT WEEK.
&&
.DISCUSSION...IT FELT LIKE AN OCTOBER DAY OUT THERE TODAY...WITH
TUCSON RECORDING ITS COOLEST HIGH TEMPERATURE SINCE WAY BACK ON MAY
24TH (83 DEGREES F). CURRENTLY...KEMX RADAR SHOWS JUST LIGHT SHOWERS
CONTINUING MAINLY SOUTH AND EAST OF TUCSON WITH TRENDS TOWARDS
SLOWLY DECREASING COVERAGE. IR SATELLITE LOOPS SHOW MOSTLY CLOUDY TO
CLOUDY SKIES AREA-WIDE...WHICH SHOULD PERSIST THROUGH THE OVERNIGHT
HOURS HELPING TO TEMPER OUR LOWS SOMEWHAT. STILL...ANOTHER COOL
MORNING IS ON TAP TOMORROW WITH BELOW-NORMAL LOWS.
BASED ON SATELLITE AND RADAR TRENDS...AS WELL AS A GLANCE AT THE
RECENT RAP...UNIV OF AZ. WRF-NAM...AND NAM12...DROPPED POPS OUT WEST
BUT WILL KEEP A MENTION OF AT LEAST ISOLATED SHOWERS THROUGH THE
OVERNIGHT PERIOD BASICALLY FROM TUCSON AND POINTS SOUTH AND EAST
WHERE SOME SUBTLE RIPPLES IN THE FLOW MAY OFFER ENOUGH DYNAMIC
SUPPORT TO CONTINUE LIGHT PRECIP THERE INTO THE MORNING HOURS.
TOMORROW MAY ONCE AGAIN BE FAIRLY SUBDUED WEATHER-WISE AS POOR MID-
LEVEL LAPSE RATES AND CLOUD COVER LIMITS OUR OVERALL INSTABILITY.
THAT SAID...THE 05/02Z RAP AND NAM12 INDICATE WE MAY GET SOME
ASSISTANCE FROM WEAK MID-LEVEL FEATURES...AND THE UPPER-LEVEL FLOW
MAY BECOME A TOUCH MORE DIFFLUENT OVERALL.
&&
.AVIATION...VALID THRU 06/06Z.
ISOLATED TO SCATTERED -SHRA WILL PERSIST OVERNIGHT BUT CONTINUE TO
GRADUALLY DECREASE IN COVERAGE SOUTH AND EAST OF KTUS. EXPECT BKN-
OVC CLOUDS AT 9-12 KFT AGL. ISOLATED TO PERHAPS SCATTERED
-SHRA/-TSRA DEVELOPING TOMORROW AFTER ABOUT 05/20Z. BRIEF MVFR
CONDITIONS POSSIBLE IN AND AROUND THE STRONGEST STORMS. OUTSIDE OF
THUNDERSTORM WIND GUSTS...SURFACE WINDS WILL GENERALLY BE LESS THAN
10 KTS AND MAINTAIN A MORE SOUTHERLY COMPONENT THAN USUAL DURING
THE AFTERNOON. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...MOIST CONDITIONS WILL LINGER THROUGH THE NEXT 24
HOURS OVER EASTERN AREAS WITH HIGH TEMPERATURES BELOW NORMAL AND
GOOD RH RECOVERY AREA WIDE. WINDS WILL FAVOR A SOUTHERLY
DIRECTION...BUT WILL BE LIGHT ENOUGH TO SEE STRONG TERRAIN
INFLUENCES. AFTERNOON SHOWERS AND ISOLATED THUNDERSTORMS WILL REMAIN
IN THE FORECAST THROUGH THE HOLIDAY WEEKEND.
&&
.PREV DISCUSSION...A FEW LINGERING LIGHT SHOWERS ARE POSSIBLE
OVERNIGHT. SCATTERED SHOWERS AND THUNDERSTORMS SHOULD FIRE UP AGAIN
ON SATURDAY AFTERNOON AS MOISTURE CONTINUES TO HANG AROUND.
THEREAFTER...THE TROUGH CURRENTLY LOCATED IN THE PAC NW WILL SWING
EWD THRU THE NRN ROCKIES. SWLY FLOW WILL CONTINUE OVER THE AREA
THROUGH SUNDAY...AND IN CONJUNCTION WITH A BREAK BETWEEN TROPICAL
SYSTEMS...WILL USHER IN SOME DRIER AIR. THIS SLIGHT DOWNTURN IN
ACTIVITY WILL BE SHORT LIVED AS THE NEXT TROPICAL SYSTEM BEGINS TO
PUSH MOISTURE NORTHWARD INTO SE AZ EARLY NEXT WEEK. BY MIDWEEK...THE
UPPER LEVEL JET IS FAIRLY ZONAL FOR A SHORT TIME AND LOCATED NEAR
THE CANADIAN BORDER...ALLOWING FOR WESTERLY FLOW ACROSS THE DESERT
SW. THE TIMING AND LOCATION FOR THE BEST PRECIP CHANCES WILL BE
HIGHLY DEPENDENT ON THE TRACK OF THIS NEXT TROPICAL SYSTEM. THAT
SAID...ONLY MINOR CHANGES WERE MADE TO INHERITED POPS THROUGH THE
MIDDLE OF NEXT WEEK.
LATE NEXT WEEK...BOTH THE 04/12Z GFS/ECMWF INDICATED NWLY FLOW
RETURNING TO THE AREA...WITH RIDGING IN THE WEST AND A TROF DIGGING
THROUGH THE GREAT LAKES REGION. THIS SHOULD HELP TO DRY THINGS OUT
WITH THE CAVEAT BEING ANY LINGERING TROPICAL MOISTURE. FOR
NOW...HAVE MAINTAINED JUST SLIGHT CHANCES FOR PRECIP FOR SRN/ERN
ZONES.
TEMPERATURES THIS WEEKEND WILL REMAIN BELOW NORMAL...FOLLOWED BY A
GRADUAL WARMING TREND TO NEAR-NORMAL LEVELS BY THE MIDDLE OF NEXT
WEEK.
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
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DISCUSSION...CARLAW
PREV DISCUSSION...FRENCH/CANTIN
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
238 PM MDT SAT SEP 5 2015
.SHORT TERM...(TONIGHT THROUGH SUNDAY NIGHT)
ISSUED AT 234 PM MDT SAT SEP 5 2015
AVAILABLE MOISTURE REMAINS ABOVE NORMAL AND IS LENDING ITSELF TO
SOME CONVECTION THAT HAS ALREADY FORMED THIS EARLY AFTERNOON.
STORMS ARE MOVING AT A GOOD CLIP SO BIGGEST CONCERN FROM STORMS
WILL BE GUSTY WINDS OF 30 TO 40 MPH WITH SOME HEAVY SHOWERS UNDER
THE STRONGER CELLS. HRRR INITIALIZED VERY WELL...MUCH BETTER THAN
NAM12/GFS...AND IT HIGHLIGHTS CURRENT CONVECTION AND MORE ISOLD
STORMS/SHOWERS AS THE AFTERNOON WEARS ON AS OPPOSED TO MORE
WIDESPREAD PRECIP. WOULDN`T BE SURPRISED TO SEE SOME STRONGER
STORMS ALONG THE PERIPHERY OF THE CLOUD SHIELD DOWN SOUTH DUE TO
DIFFERENTIAL HEATING. EITHER WAY...ONE LAST DAY OF SHOWERS AND
THUNDERSTORMS BEFORE DRYING REALLY KICKS IN. MOST CONVECTION WILL
DIE DOWN SHORTLY AFTER SUNSET THOUGH A FEW ISOLATED SHOWERS/STORMS
POSSIBLE OVERNIGHT.
SUNDAY THE STALLED FRONT STRETCHED ACROSS THE CENTRAL FORECAST
AREA QUICKLY ERODES. ITS DRIER AIR MASS DOES LIMIT AVAILABLE
MOISTURE. BETTER MOISTURE REMAINS OVER THE SOUTHERN AND CENTRAL
ZONES FOR ANOTHER ROUND OF SCATTERED LATE DAY SHOWERS AND STORMS.
TEMPERATURES WILL SHOW LITTLE CHANGE.
SUNDAY NIGHT THE NEXT TROUGH WORKS THROUGH THE NORTHERN ROCKIES
FOR SOME FORCING NEAR THE WYOMING BORDER. SHOWERS MAY PERSIST INTO
MONDAY MORNING OVER NW COLORADO.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 234 PM MDT SAT SEP 5 2015
PROGRESSIVE WESTERLIES ACROSS THE NORTHERN TIER OF STATES PROVIDE
A DRIER W-NW FLOW THROUGH THE NEW WORK WEEK. THIS PROVIDES A DRY
WEEK IN THE MIDST OF WHAT IS NORMALLY OUR WETTEST TIME OF YEAR.
MONDAY THROUGH TUESDAY...OPEN TROUGHS CONTINUE TO SWEEP THROUGH
THE NORTHERN ROCKIES. WEAK FORCING ACROSS THE NORTH IS LIMITED BY
A DRY AIR MASS THERE. ISOLATED TO SCATTERED LATE-DAY STORMS WILL
FAVOR THE CENTRAL-SOUTHERN COLORADO MOUNTAINS. AFTERNOONS WILL BE
BREEZY TO WINDY AT TIMES.
WEDNESDAY THROUGH THURSDAY...DISTURBANCES CONTINUE TO DIVE THROUGH
THE NORTHERN ROCKIES BUT WITH THE SUB-TROPICAL RIDGE AMPLIFYING
ALONG THE WEST COAST SHIFTS THE FLOW TO DRIER NW. STORM COVERAGE
WILL BE ISOLATED AT BEST. AFTERNOON TEMPERATURES CLIMB WELL ABOVE
NORMAL FOR LATE SUMMER.
FRIDAY THROUGH SATURDAY...THE RIDGE AMPLIFIES ALONG THE WEST
COAST. THE EC HAS THE RIDGE INLAND WHILE THE PREFERRED GFS KEEPS
THE RIDGE CENTER OFFSHORE. EITHER SOLUTION SHIELDS THE REGION FROM
HURRICANE IGNACIO AND KEEPS THE DRY PATTERN IN PLACE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 235 PM MDT SAT SEP 5 2015
LATE DAY STORMS ARE FAST MOVING...TO THE NE AT 20-25KTS. FOR MTN
TAF SITES AND KMTJ...CIG/VIS MAY DROP BRIEFLY BELOW ILS BREAK
POINTS. CONVECTION WILL DIE DOWN BY 03Z WITH ONLY ISOLATED
SHOWERS/STORMS CONTINUING OVERNIGHT. AFT 18Z SUNDAY STORMS WILL BE
ISOLATED IN COVERAGE MAINLY SOUTH OF THE I-70 CORRIDOR.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...TGR/JOE
LONG TERM...JOE
AVIATION...JOE
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1114 PM MDT FRI SEP 4 2015
.UPDATE...
ISSUED AT 1059 PM MDT FRI SEP 4 2015
A DISTURBANCE PRODUCING A THICK LINE OF SHOWERS AND THUNDERSTORMS
ALONG THE CO AND UT BORDER WILL MOVE THROUGH SW AND CENTRAL CO
BETWEEN 11 PM AND ABOUT 3 AM. HAVE INCREASED POPS...CLOUDS...AND
QPF TO SHOW THIS LINE PROGRESSING ACROSS THE SOUTHERN TWO THIRDS
OF THE CWA IN THE NEXT SEVERAL HOURS.
&&
.SHORT TERM...(TONIGHT THROUGH SATURDAY NIGHT)
ISSUED AT 344 PM MDT FRI SEP 4 2015
AN UNSETTLED MOIST SW FLOW CONTINUES THROUGH THESE PERIODS.
THIS AFTERNOON-OVERNIGHT...THE MORNING MODEL RUNS CONTINUE TO NOT
RESOLVE ORGANIZED FORCING. JET SUPPORT REMAINS STRETCHED SW-NE
ACROSS THE FORECAST AREA AND PRECIP WATER VALUES ARE NEAR ONE INCH
IN THE LOWER ELEVATIONS. STORM MOTION IS BRISK...TO THE NE AT
25KTS. THE HRRR SEEMS TO BE CAPTURING THE EARLY AFTERNOON SHOWER
COVERAGE WITH THE NAM AND GFS TOO WET FOR THIS EVENING. THE HRRR
SUGGESTS THE EVENING STORMS WILL BE MAINLY NEAR THE CONTINENTAL
DIVIDE AND PERHAPS THE EASTERN UINTAS. THEN ISOLATED TO SCATTERED
SHOWERS LINGER OVER THE SOUTH INTO SATURDAY MORNING.
IF TODAY IS ANY INDICATION OF HOW TOMORROW WILL BE...THEN SOME SHOWERS
AND THUNDERSTORMS ARE EXPECTED BUT NOTHING TOO IMPRESSIVE. MODELS
HAVE BEEN OVERDOING COVERAGE AND INTENSITY LAST FEW DAYS WITH BOTH
NAM AND GFS PAINTING WIDESPREAD PRECIPITATION WHICH JUST HASN`T
BEEN PANNING OUT. EVEN WITH DECENT UPPER LEVEL SUPPORT...THERE`S
NOT BEEN ANY REAL GOOD SURFACE TRIGGER TO GET STRONG CONVECTION
GOING. FOR SATURDAY...GFS SHOWING ANOTHER DAY OF WIDESPREAD PRECIP
WHILE NAM HAS REALLY PULLED BACK. FORECAST FOLLOWS NAM SO DROPPED
POPS GOOD AMT. THAT`S NOT TO SAY WE WON`T SEE ANY PRECIP...WE
WILL...SOME AFTN/EVENING THUNDERSTORMS ARE EXPECTED WITH SOME
HEAVY RAIN UNDER THE STRONGER CELLS. EXPECT COVERAGE WILL BE
SIMILAR TO TODAY. OF COURSE...HAVING SAID THAT CHANCE HAS NOW
INCREASED FOR TOMORROW TO BE VERY ACTIVE DAY. STAY TUNED. AS FAR
AS TEMPS ARE CONCERNED...PLENTY OF CLOUD COVER WILL KEEP TEMPS
NEAR NORMAL TO A FEW DEGREES BELOW.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 344 PM MDT FRI SEP 4 2015
A FEW DAYS OF NICE WEATHER ON TAP AS LOW PRESSURE SHIFTS NORTH AND
THE ASSOD TROUGH FORCES THE MOISTURE STREAM TO OUR EAST. A FEW
GARDEN VARIETY SHOWERS/STORMS MAY POPUP IN THE AFTERNOON/EVENING
MORE SO FOR MONDAY AND TUESDAY BUT THEY WILL BE VERY FEW AND FAR
BETWEEN FAVORING THE HIGHEST TERRAIN. MOST OF THE CWA WILL SEE
PLENTY OF SUN WITH SOME CU BUILDUP IN THE AFTERNOON WITH SCATTERED
SKIES BEING PREDOMINANT.
THE REMAINDER OF THE LONG TERM WILL SEE PIECES OF ENERGY ROTATING
AROUND THE PERIPHERY OF HIGH PRESSURE TO OUR SOUTH KICKING OFF
SOME SHOWERS/STORMS MAINLY OVER THE SAN JUANS. MEAN FLOW REMAINS
FROM THE WEST TO NORTHWEST KEEPING TEMPS SEASONABLE FOR THIS TIME
OF YEAR.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1059 PM MDT FRI SEP 4 2015
A LINE OF SHOWERS AND THUNDERSTORMS WILL MOVE ACROSS THE FORECAST
AREA FROM WEST TO EAST UNTIL ABOUT 09Z. KGJT...KRIL...KEGE...
KMTJ...AND KTEX WILL BE AFFECTED BY STORMS WITH A HIGH PROBABILITY
OF CONDITIONS BELOW ILS CUTOFFS AND WIND GUSTS TO ABOUT 40 MPH.
EACH OF THESE SITES HAS ABOUT A 20 PERCENT CHANCE OF MVFR CIGS AND
VSBYS UNTIL ABOUT 09Z.
FOR THE REST OF THE TIME PERIOD MOIST SOUTHWEST FLOW WILL KEEP
ISOLATED TO SCATTERED SHOWERS POPPING OVER THE EASTERN GREAT BASIN
TO THE ROCKIES OVERNIGHT. IN GENERAL THINGS QUIET DOWN LATE
TONIGHT WITH A RETURN OF THE SHOWER AND THUNDERSTORM ACTIVITY
TOMORROW AFTERNOON.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
UPDATE...CC
SHORT TERM...JOE/TGR
LONG TERM...TGR
AVIATION...CC
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
934 PM EDT SUN SEP 6 2015
.UPDATE (REST OF TONIGHT)...
CONVECTION HAS DIMINISHED OVER THE LAST SEVERAL HOURS. CONDITIONS
WILL BE FAVORABLE FOR SHOWERS AND ISOLATED THUNDERSTORMS TO
DEVELOP OVER NIGHT OVER THE COASTAL WATERS. EASTERLY FLOW WILL
ALLOW SOME OF THOSE STORMS TO IMPACT COASTAL COUNTIES THROUGH THE
MORNING HOURS TOMORROW. BROAD MID- LEVEL LOW PRESSURE SYSTEM NOTED
ON IR IMAGERY AND RAP ANALYSIS WITH WEAK OPEN SURFACE TROUGH OVER
THE GULF SHOULD SUSTAIN MOSTLY CLOUDY CONDITIONS INTO TOMORROW
MORNING.
&&
.AVIATION...
VCSH POSSIBLE IN THE EARLY MORNING HOURS AT ALL COASTAL
TERMINALS. POTENTIAL FOR IFR CEILINGS...BUT FOR THIS PACKAGE HAVE
GONE WITH MVFR FOR MOST SITES. FOG POTENTIAL IS THERE BUT APPEARS
TO BE MAINLY 3-5 SM RANGE GIVEN THE AMOUNT OF MID AND HIGH LEVEL
CLOUDS IN THE AREA.
&&
.MARINE...
A FAIRLY STRONG GRADIENT BETWEEN A SURFACE HIGH PRESSURE SYSTEM
OVER THE CAROLINAS AND A WEAK LOW OVER THE GULF WILL BEGIN TO
RELAX TONIGHT AND WINDS WHICH ARE CURRENTLY AROUND 15 KNOTS FROM
THE NE OVER THE COASTAL GA WATERS WILL BEGIN TO BACK OFF. SEAS
WILL REMAIN 2 TO 4 FEET THROUGH TONIGHT. SHOWERS AND THUNDERSTORMS
WILL DEVELOP THROUGH THE NIGHT AND INCREASE IN COVERAGE HEADING
INTO TOMORROW MORNING.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 70 88 71 90 / 20 60 30 60
SSI 74 85 75 88 / 40 50 20 40
JAX 72 87 73 90 / 30 60 20 60
SGJ 74 86 75 88 / 30 60 20 60
GNV 71 88 71 90 / 30 70 40 70
OCF 71 88 72 90 / 40 70 30 70
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...NONE.
&&
$$
WALSH/NELSON/COMBS
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
353 PM EDT SAT SEP 5 2015
.REST OF THE AFTERNOON...SCT TO NUMEROUS SHOWERS AND STORMS
FORMED QUICKLY TODAY OVER NE FL AND PROPAGATED WWD TO INLAND
AREAS. COVERAGE ENDING UP A BIT HIGHER SO HAVE ADJUSTED POPS TO
60-70 PERCENT OVER INLAND NE FL. MAIN CONCERNS WILL BE GUSTY
WINDS...LIGHTNING AND HEAVY DOWNPOURS. FOR SE GA AND REST OF
COASTAL NE FL ONLY 20-40 PERCENT RAIN CHANCES EXPECTED PER RADAR
TRENDS AND HRRR MODEL RUNS. PREVAILING FLOW ON LATEST ANALYSIS IS
NE TO E WITH THE FOCUS OF CONVERGENCE OVER THE SUWANNEE VALLEY
AREA.
.SHORT TERM /TONIGHT THROUGH TUESDAY/...
TONIGHT...AS MENTIONED...FOCUS OF CONVECTION WILL BE OVER
INTERIOR NERN FL WITH ACTIVITY WINDING DOWN FAIRLY QUICKLY THROUGH
THE EVENING HOURS. WARM OCEAN WATERS AND CONVERGENCE IN N TO NE
10-15KT FLOW SHOULD ALLOW FOR OCNL ISOLD TO SCT SHOWERS AND
PERHAPS A THUNDERSTORM FOR THE ATLC MARINE WATERS. SOME SHOWER
ACTIVITY OFF THE ATLC WATERS WILL BE POSSIBLE FOR THE COASTAL
COUNTIES OVERNIGHT WITH 0-5KFT LEVEL FLOW JUST STRONG ENOUGH AT
10-15 KT. SFC HIGH PRES RIDGE WILL REMAIN ACROSS THE MID ATLC AREA
AT 1024 MB.
SUNDAY...WEAK INVERTED TROUGH BEGINS THE DAY ALONG THE COASTAL
WATERS WITH HIGH PRES RIDGE NOSING DOWN THROUGH NRN GA AND AL.
GFS AND NAM SUGGESTS SOMEWHAT LOWER MOISTURE TO WORK WITH FOR
CONVECTIVE CHANCES. THINK HIGH END SCATTERED RANGE AROUND 40-50
PERCENT IS REASONABLE AT THIS TIME. SHOWERS AND STORMS WILL BEGIN
OVER THE ERN ZONES FIRST HALF OF THE DAY...LIKE TODAY...THEN
PROPAGATE INLAND. WITH A SLIGHTLY STRONGER CAP...INSTABILITY
RELEASED IN THE AFTN COULD RESULT IN ISOLD STRONG STORMS GIVEN A
BIT STEEPER LAPSE RATES WITH THE MID AND UPPER LEVEL LOW MOVING
ACROSS THE REGION. TEMPS EXPECTED FROM MID 80S TO NEAR 90...LOWER
THAN PRIOR DAYS WITH 850 MB TEMPS AT LEAST 1 DEG LOWER. NE-E
WINDS STAY BELOW BREEZY LEVELS.
SUNDAY NIGHT THROUGH TUESDAY...
THIS PERIOD WILL BE MARKED BY A CONTINUATION OF WARM AND HUMID
CONDITIONS WITH SCATTERED TO NUMEROUS SHOWERS AND STORMS EACH DAY.
THE CLOSED UPPER LOW OVER THE REGION WILL CONTINUE TO RETROGRADE
WEST SOUTHWEST SUNDAY NIGHT INTO EARLY NEXT WEEK. UPPER RIDGING TO
OUR SOUTHEAST WILL TAKE BACK OVER BY MID WEEK AS THE UPPER LOW
RETROGRADES ALL THE WAY TO THE WESTERN GULF OF MEXICO. AT THE
SURFACE...AN INVERTED TROUGH NEAR THE COAST WILL REMAIN
INFLUENTIAL EARLY IN THE WEEK. DEEP MOISTURE WILL REMAIN IN PLACE
AND OUR DIURNAL STORM CHANCES WILL REMAIN HIGHER THAN NORMAL FOR
THIS TIME OF YEAR. ONSHORE FLOW WILL INITIALLY FAVOR AN EAST TO
WEST PROGRESSION OF SHOWERS/STORMS WITH ACTIVITY GETTING STARTED
NEAR THE ATLANTIC COAST DURING THE MORNING HOURS. BY
TUESDAY...FLOW WILL BECOME LIGHT ENOUGH TO SUPPORT AN EARLY START
TO BOTH SEABREEZES WITH CONVECTION MOVING IN FROM BOTH COASTS
DURING THE MORNING HOURS.
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
INVERTED TROUGH BREAKS DOWN AND SURFACE RIDGING WILL SHIFT TO OUR
SOUTH AS A FRONT STALLS TO OUR NORTH. THIS WILL SHIFT THE PATTERN
TO A SOUTHWESTERLY FLOW WITH AT LEAST SCATTERED SHOWERS/STORMS
PROGRESSING WEST TO EAST EACH DAY WITH ACTIVITY GETTING OFF TO A
MORNING START ACROSS OUR WESTERN ZONES. BROAD UPPER TROUGHING WILL
BRING A DECREASE IN HEIGHTS BY LATE IN THE WEEK...BUT THE OVERALL
FORECAST DOES NOT CHANGE ALL THAT MUCH...PERHAPS A LITTLE LOWER
ON DAYTIME TEMPS...BUT RAIN CHANCES WILL REMAIN ABOVE NORMAL
LEVELS.
&&
.AVIATION...SHOWERS AND STORMS AFFECTING LOCATIONS AROUND GNV AND
SGJ WITH MOST OTHER ACTIVITY IN THE VICINITY. ANTICIPATE
PREVAILING VFR LATER THIS AFTERNOON AND OVERNIGHT. MVFR VSBY IN
BR POSSIBLE AT GNV AND VQQ AFTER 06Z-13Z. SHOWERS AND A FEW
STORMS POSSIBLE BY MID TO LATE SUN MORNING BUT CHANCES REMAIN LOW
WITH VCSH FOR NOW BY 15Z.
&&
.MARINE...NE TO E FLOW EXPECTED THROUGH SUNDAY AS HIGH PRES
WEDGES SOUTH TO ACROSS THE APPALACHIANS. WINDS AND SEAS STILL
EXPECTED TO REMAIN BELOW HEADLINE CRITERIA. WINDS DECREASE
BEGINNING EARLY NEXT WEEK AS THE WEDGE AND INVERTED TROUGH WEAKEN.
RIP CURRENTS: A LOW RISK CONTINUES TODAY WITH A MODERATE RISK
POSSIBLE FOR SUNDAY AS AN ONSHORE FLOW INCREASES.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 71 89 70 89 / 30 40 10 50
SSI 75 85 74 85 / 20 50 30 40
JAX 73 87 71 88 / 20 40 20 50
SGJ 75 86 74 85 / 20 50 20 50
GNV 70 89 71 88 / 20 40 30 60
OCF 71 89 71 88 / 20 50 30 60
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...NONE.
&&
$$
SHASHY/SHULER/
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
1005 PM EDT SUN SEP 6 2015
.SYNOPSIS...
AS AN INLAND WEDGE OF HIGH PRESSURE WEAKENS EARLY THIS
WEEK...A WEAK COASTAL TROUGH WILL MOVE INLAND AND DISSIPATE.
ATLANTIC HIGH PRESSURE WILL THEN BUILD WEST UNTIL A COLD FRONT
APPROACHES THE AREA NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
SHOWERS/TSTMS ARE SLOWLY EXPANDING ACROSS THE COASTAL WATERS THIS
EVENING IN RESPONSE TO INTENSIFYING SURFACE MOISTURE FLUX
CONVERGENCE /SMC/. AS OF 07/01Z...THE STRONGEST SMC WAS LOCATED
ALONG THE GEORGIA AND NORTHEAST FLORDIA COASTS WHERE MSAS PINGED
VALUES 30-50 G/KG/12HR. HIGH RESOLUTION MODELS ARE SIMILAR IN
SHOWING THE CORRIDOR OF STRONGEST SMC SHIFTING UP THE COAST
OVERNIGHT AS THE OFFSHORE COASTAL TROUGH MOVES SLIGHTLY WEST AND
THE RESULTING PINCHING OF THE PRESSURE GRADIENT MOVES NORTH. THE
STRONGEST SMC...VALUES 75-100 G/KG/12...ARE FORECAST TO BE ALIGNED
ALONG THE LOWER SOUTH CAROLINA COAST BY 2-4 AM WITH HIGHEST
VALUES BECOMING SITUATED OVER THE CHARLESTON TRI-COUNTY AREA.
GIVEN CURRENT RADAR TRENDS...AN INCREASE IN POPS SEEMS IN ORDER
FOR THE OVERNIGHT PERIOD. WILL INCREASE POPS TO 70 PERCENT ACROSS
THE CHARLESTON TRI-COUNTY AREA WITH 50-60 POPS ELSEWHERE ALONG THE
UPPER GEORGIA AND LOWER SOUTH CAROLINA COASTS. IT IS UNCLEAR HOW
FAR INLAND THE RAIN WILL PENETRATE...BUT SOME SLIGHT UPWARD
ADJUSTMENTS SEEM WARRANTED TO THE I-95 CORRIDOR WITH DRY
CONDITIONS GENERALLY HOLDING ROUGHLY WEST OF A WALTERBORO-
SPRINGFIELD-LUDOWICI LINE.
THE BLENDED TOTAL PRECIP WATER PRODUCT SHOWS A RIBBON OF PWATS
EXCEEDING 2 INCHES ALONG THE BEACHES AND EXTENDING OFFSHORE WHICH
IS PROGGED MOVE SLOWLY WEST WITH TIME WITH THE 850-700 HPA SHEAR
AXIS. THE MEAN WIND PATTERN LOOKS STRONG ENOUGH TO PRECLUDE
SIGNIFICANT FLOODING PROBLEMS...BUT HIGH PRECIPITATION RATES
COMBINED WITH HIGH TIDE AROUND 4 AM SUGGESTS THERE IS A RISK FOR
AT LEAST MINOR FLOODING IN THE DOWNTOWN CHARLESTON AREA PRIOR TO
SUNRISE SUNDAY.
EARLIER SHOWER/TSTM ACTIVITY DROPPED TEMPERATURES INTO THE LOWER-
MID 70S AT THE COAST...SO A DOWNWARD ADJUSTMENT WAS NEEDED TO THE
LOW TEMPERATURE FORECAST.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
MONDAY...THE UPPER LOW WILL GRADUALLY RETROGRADE INLAND FROM THE
FORECAST AREA...AND THE INLAND WEDGE OF HIGH PRESSURE WILL
WEAKEN/RETREAT INLAND. AS A RESULT...THE SURFACE TROUGH OF LOW
PRESSURE IS PROGGED TO PUSH ONSHORE...ALTHOUGH THE 06/12 EUROPEAN
SOLUTION DEPICTS A MUCH SLOWER EROSION OF THE WEDGE/INLAND
PROGRESSION OF THE SURFACE TROUGH AS COMPARED WITH THE GFS/NAM.
NEVERTHELESS...THE FOCUS FOR SHOWERS/THUNDERSTORMS ALONG THE
COAST/ACROSS ADJACENT COASTAL WATERS DURING THE MORNING IS EXPECTED
TO SHIFT INLAND DURING THE AFTERNOON...EITHER ALONG THE SURFACE
TROUGH OR ALONG THE SEA BREEZE. CAPPED MAXIMUM POPS AT 50 PERCENT
IN THE MORNING NEAR THE COAST AND IN THE AFTERNOON ALONG/WEST OF
INTERSTATE 95...BUT LOCALLY GREATER POPS COULD EVENTUALLY BE
REQUIRED. PWATS AROUND 2 INCHES COULD SUPPORT LOCALLY HEAVY
RAINFALL. HOWEVER...INSTABILITY REMAINS UNIMPRESSIVE WITH CLOUDS
LIMITING HIGH TEMPS TO THE MIDDLE 80S...PERHAPS EVEN LOWER 80S
IF/WHERE SHOWERS PERSIST...SO THE POTENTIAL FOR ANY SEVERE WEATHER
REMAINS VERY LOW.
MONDAY NIGHT...INLAND SHOWERS/THUNDERSTORMS WILL GRADUALLY DISSIPATE
AS THE ENVIRONMENT COOLS/STABILIZES...AND THE FOCUS FOR OVERNIGHT
SHOWERS/THUNDERSTORMS WILL SHIFT BACK TO COASTAL COUNTIES/ADJACENT
COASTAL WATERS AS WEAK LOW-LEVEL MOISTURE TRANSPORT/MASS
CONVERGENCE DEVELOP. MODEL SIGNALS ARE NOT OVERLY IMPRESSIVE... THUS
OVERNIGHT POPS ARE CAPPED AT 30-40 PERCENT. PWATS REMAIN
ELEVATED...SO LOCALLY HEAVY RAINFALL CANNOT BE RULED OUT NEAR THE
COAST.
TUESDAY THROUGH WEDNESDAY...AT THE SURFACE THE INLAND WEDGE WILL
DISSIPATE AND WILL BE REPLACED BY ATLANTIC HIGH PRESSURE BUILDING
ONSHORE. ALOFT...THE UPPER LOW/TROUGH WILL CONTINUE TO RETROGRADE
WEST AND AWAY FROM THE FORECAST AREA...AND AN UPPER RIDGE WILL
EXPAND OVER THE REGION FROM THE SOUTHEAST. THIS WILL SUPPORT A
WARMING TREND WITH DAYTIME HIGHS IN THE UPPER 80S/LOWER 90S SHOULD
BECOME MORE COMMON AWAY FROM THE COAST...ESPECIALLY WEDNESDAY.
BETWEEN THE INLAND TROUGH AND THE COASTAL RIDGE...INCREASING
SOUTH/SOUTHWEST FLOW WILL INCREASE AND WILL USHER A POOL OF ENHANCED
MOISTURE INTO THE SOUTHEAST AS DEPICTED BY PROGS OF 850-500 MB MEAN
RH/FORECAST PWATS. THUS...AN ACTIVE CONVECTIVE REGIME SHOULD PERSIST
WITH AT LEAST SCATTERED SHOWERS/THUNDERSTORMS...NEAR THE COAST AND
ACROSS ADJACENT COASTAL WATERS BOTH MORNINGS AND EACH AFTERNOON/
EARLY EVENING ESPECIALLY INLAND. CAPPED MAXIMUM/PM POPS AT 40-50
PERCENT...BUT LOCALLY GREATER POPS COULD EVENTUALLY BE REQUIRED.
PWATS AROUND 2 INCHES COULD SUPPORT LOCALLY HEAVY RAINFALL...AND
SOMEWHAT STRONGER INSTABILITY COULD SUPPORT AN ISOLATED PULSE
THUNDERSTORM OR TWO DURING THE AFTERNOON/EARLY EVENING HOURS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE AREA WILL REMAIN BETWEEN HIGH PRESSURE OVER THE WESTERN ATLANTIC
AND A LARGE TROUGH OF LOW PRESSURE SHIFTING OVER THE CENTRAL UNITED
STATES. THE PATTERN WILL RESEMBLE ONE MORE TYPICAL DURING THE
SUMMERTIME...WITH AFTERNOON SHOWERS AND THUNDERSTORMS EACH DAY
THROUGH LATE WEEK. THE PATTERN THEN LOOKS FAIRLY ACTIVE BY THE
WEEKEND AS A COLD FRONT APPROACHES THE WEST/NORTHWEST AND SLOWLY
SHIFTS OVER THE AREA. HEAVY RAIN AND PERHAPS SOME STRONGER STORMS
WILL BE POSSIBLE. HAVE MAINTAINED CHANCES OF SHOWERS AND
THUNDERSTORMS THIS WEEKEND...BUT POPS WILL LIKELY NEED TO BE
ADJUSTED WHEN CONFIDENCE BECOMES HIGHER IN THE TIMING OF FROPA.
OVERALL HIGH TEMPS SHOULD RANGE AROUND 90 THROUGH LATE WEEK...THEN
IN THE UPPER 80S THIS WEEKEND. OVERNIGHT LOWS WILL BE IN THE LOWER
70S AWAY FROM THE COAST.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
KCHS...LOW CIGS AND RAIN IMPACTS ARE THE PRIMARY CONCERN THROUGH
SUNRISE. LATEST RAP DATA SUGGESTS IFR CIG PROBABILITIES ARE
INCREASING..ESPECIALLY 06-09Z BEFORE RAIN MOVES IN FROM OFFSHORE.
WILL SHOW SCT006 BKN010 AFTER 06Z...BUT INCREASE CIGS SLIGHTLY TO
BKN015 WITH A TEMPO GROUP 3SM RA SCT010 BKN025 FROM 09-12Z TO
ACCOUNT FOR RAIN MOVING IN FROM THE COAST. RAIN/LOW CLOUDS MAY
LINGER CLOSER TO 15Z...BUT DATA IS NOT FIRM ON THAT JUST YET.
ADJUSTMENTS WILL MOST LIKELY BE NEEDED AS CONFIDENCE INCREASES.
KSAV...LOW CIGS IS THE PRIMARY CONCERN THROUGH SUNRISE. LATEST RAP
DATA SHOW LOW CLOUDS EXPANDING ALONG THE I-95 CORRIDOR AFTER 06Z
AND LIKELY EXPANDING TO THE KSAV TERMINAL BY 07-09Z. WILL SHOW
PREVAILING IFR CIGS BY 09Z...BUT SOME ADJUSTMENTS TO THIS WILL
LIKELY BE NEEDED AS CEILING TRENDS BECOME ESTABLISHED. CIGS ARE
EXPECTED TO LIFT TO MVFR BY 13Z AND VFR BY 15Z...BUT IFR CIGS
COULD LINGER A BIT LONGER. THERE IS A POSSIBILITY THAT SHOWERS
COULD IMPACT THE TERMINAL AFTER 09Z...BUT HIGH RESOLUTION DATA
SUGGEST THE BULK OF ANY RAINFALL WILL REMAIN NORTHEAST AND EAST OF
THE TERMINAL.
EXTENDED AVIATION OUTLOOK...BRIEF FLIGHT RESTRICTIONS ARE POSSIBLE
DUE TO EARLY MORNING STRATUS/FOG AND WITHIN ANY SHOWERS/THUNDERSTORMS.
HOWEVER...VFR WILL PREVAIL MUCH OF THE TIME.
&&
.MARINE...
TONIGHT...WITH HIGH PRESSURE TO THE NORTH THE PREVAILING LOW
LEVEL FLOW WILL CONTINUE TO BE NORTHEASTERLY THROUGH MUCH OF THE
NIGHT. SPEEDS WILL CONTINUE TO BE AROUND 15 KT...AND PERHAPS INTO
THE 15-20 KT RANGE AT TIMES. THEN LATE TONIGHT...THE GRADIENT WILL
BEGIN TO RELAX AS THE COASTAL TROUGH DRIFTS CLOSER TO SHORE.
SPEEDS WILL DROP OFF MORE INTO THE 10-15 KT RANGE THROUGH SUNRISE.
SEAS WILL BE 2-4 FT THROUGH MUCH OF THE NIGHT AND WILL BEGIN TO
COME DOWN INTO THE 2-3 FT RANGE LATE AS WINDS DIMINISH.
MONDAY THROUGH FRIDAY...EARLY THIS WEEK THE INLAND WEDGE OF HIGH
PRESSURE WILL WEAKEN AND DISSIPATE...THE COASTAL TROUGH WILL PUSH
ONSHORE AND WILL DISSIPATE...AND ATLANTIC HIGH PRESSURE WILL BUILD
WEST OVER THE WATERS. AS THIS TRANSITION OCCURS...NE WINDS 10-15 KT
MONDAY WILL VEER TO THE E/SE AROUND 10 KT MONDAY NIGHT THROUGH
TUESDAY...THEN WINDS WILL VEER TO THE S/SW AT 15 KT OR LESS TUESDAY
NIGHT THROUGH THURSDAY. SEAS OF 1-3 FT WILL PREVAIL...HIGHEST BEYOND
20 NM.
WINDS/SEAS WILL THEN GRADUALLY INCREASE/BUILD LATE WEEK AS THE
GRADIENT BECOMES ENHANCED WITH A TROUGH OF LOW PRESSURE APPROACHING
FROM THE WEST/NORTHWEST. HOWEVER...CONDITIONS ARE EXPECTED TO REMAIN
BELOW SMALL CRAFT ADVISORY LEVELS.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
ST
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
800 PM EDT SUN SEP 6 2015
.SYNOPSIS...
AN UPPER LOW OVER THE FORECAST AREA WILL SHIFT SOUTHWESTWARD
THROUGH MONDAY WITH A COOL AND MOIST FLOW OFF THE ATLANTIC. AN
UPPER RIDGE WILL BUILD OVER THE AREA BY MID WEEK BRINGING WARMING
TEMPERATURES. A COLD FRONT AND UPPER TROUGH WILL BRING UNSETTLED
WEATHER FOR THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
SURFACE ANALYSIS SHOWS AN AREA OF HIGH PRESSURE CENTERED OVER NEW
ENGLAND CONTINUING TO RIDGE DOWN THE EAST COAST INTO THE
CAROLINAS. MEANWHILE AN UPPER AREA OF LOW PRESSURE IS MOVING
WESTWARD THROUGH THE CAROLINAS.
SHOWERS AND A FEW THUNDERSTORMS HAVE BEEN MOVING SOUTHWEST ACROSS
THE REGION FROM THE COAST DURING THE AFTERNOON AND EARLY EVENING
IN WEAKLY TO MODERATELY UNSTABLE AIR MASS. LATEST RADAR TRENDS
SUGGEST SHOWERS DIMINISHING. HRRR MODEL SUPPORTS WEAKENING.
DECREASING POPS DURING THE EVENING ON TRACK.
MODELS ARE INDICATING POSSIBLE REDEVELOPMENT OF SHOWERS TOWARDS
MORNING.
STRATUS DECK LATE TONIGHT WILL LIMIT COOLING. LATEST MOS
CONSENSUS APPEARS ON TRACK FOR OVERNIGHT LOWS.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
AN UPPER LOW OFF OF THE SOUTHEAST COAST WILL DRIFT SOUTHWESTWARD
TO THE GULF COAST ON MONDAY WITH SURFACE HIGH PRESSURE SLOWLY
SINKING FURTHER SOUTH INTO THE FORECAST AREA. COOL TEMPERATURES
ALOFT...DIURNAL HEATING AND DECENT MOISTURE WILL TRIGGER SCATTERED
CONVECTION MAINLY IN THE AFTERNOON AND EARLY EVENING. CHANCE POPS
LOOK GOOD FROM PREVIOUS FORECAST PACKAGE WITH HIGHEST POPS EAST.
NEAR NORMAL TEMPERATURES IN THE 80S FOR HIGHS AND LOWS AROUND 70.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
ECMWF AND GFS MODELS SHOW RIDGING IN THE WESTERN US WITH A TROF IN
THE EAST IN THE EXTENDED PERIOD. SHORTWAVE ENERGY DIVING
SOUTHEAST ACROSS THE MIDWEST INTO THE CAROLINAS BY LATE WEEKEND
WILL INCREASE CONVECTION CHANCES SATURDAY AND SUNDAY. TEMPERATURES
DURING THIS PERIOD WILL BE ABOVE NORMAL WITH HIGHS IN THE LOWER
90S WED-THU...A LITTLE COOLER BY THE WEEKEND.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
THUNDERSTORM ACTIVITY HAS DISSIPATED THIS EVENING WITH A FEW
ISOLATED SHOWERS REMAINING ACROSS MAINLY THE EAST. BRIEF MVFR
RESTRICTIONS AT THE TERMINALS ARE POSSIBLE WITH A PASSING SHOWER BUT
DO NOT APPEAR LIKELY BASED ON CURRENT RADAR TRENDS. LATER
TONIGHT...MVFR TO POSSIBLY IFR CIGS COULD REDEVELOP AS A STRATUS
DECK DEVELOPS ACROSS THE REGION. A 20 TO 25 KNOT LOW LEVEL JET
SHOULD RESULT IN MAINLY STRATUS OVER FOG. MODELS SHOW IMPROVEMENT
AROUND MID-DAY TO EARLY AFTERNOON WHICH ALIGNS WELL WITH THE
PERSISTENCE FORECAST. ANOTHER CHANCE FOR CONVECTION MONDAY AFTERNOON
WITH THE BEST CHANCE SOUTH AND EAST. WINDS WILL GENERALLY BE OUT OF
THE NORTHEAST THROUGH THE PERIOD AT 10 KNOTS OR LESS.
EXTENDED AVIATION OUTLOOK...LATE NIGHT/MORNING FOG/STRATUS
POSSIBLE...WITH A CHANCE OF AFTERNOON SHOWERS AND POSSIBLE
THUNDERSTORMS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
87
AREA FORECAST DISCUSSION...CORRECTED
NWS CHARLESTON SC
737 PM EDT SUN SEP 6 2015
.SYNOPSIS...
AS AN INLAND WEDGE OF HIGH PRESSURE WEAKENS EARLY THIS
WEEK...A WEAK COASTAL TROUGH WILL MOVE INLAND AND DISSIPATE.
ATLANTIC HIGH PRESSURE WILL THEN BUILD WEST UNTIL A COLD FRONT
APPROACHES THE AREA NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
HIGH RESOLUTION MODELS ARE CONVERGING ON A SIMILAR SOLUTION FOR
THE OVERNIGHT PERIOD. THERE ARE SIGNALS THAT SCATTERED TO NUMEROUS
SHOWERS/TSTMS WILL REDEVELOP OVER THE COASTAL WATERS AND THE
ADJACENT BEACHES AFTER MIDNIGHT AS IMPRESSIVE SURFACE MOISTURE
FLUX CONVERGENCE /SMC/ INTENSIFIES IN THE NORTHEAST LOW-LEVEL
FLOW REGIME. THE LATEST RAP SHOWS SMC VALUES INCREASING >50
G/KG/12HR AFTER MIDNIGHT AND INCREASING FURTHER TO 100 G/KG/12HR
ACROSS THE LOWER SOUTH CAROLINA COAST EARLY MONDAY. BOTH THE RAP
AND H3R CORRESPONDINGLY SHOW A LARGE BAND OF MODERATE TO LOCALLY
HEAVY RAIN EXPANDING FROM THE COASTAL WATERS AND INTO THE AREAS
ROUGHLY ALONG AND EAST OF A HILTON HEAD-NORTH CHARLESTON-
MCCLELLANVILLE LINE BETWEEN 3 AM AND SUNRISE. THIS SCENARIO SEEMS
REASONABLE GIVEN THE EXPECTED POSITIONING OF THE COASTAL TROUGH
OFFSHORE. THE BLENDED TOTAL PRECIP WATER PRODUCT SHOWS A RIBBON OF
PWATS EXCEEDING 2 INCHES ALONG THE BEACHES AND EXTENDING OFFSHORE
WHICH IS PROGGED MOVE SLOWLY WEST WITH TIME WITH THE 850-700 HPA
SHEAR AXIS. THE MEAN WIND PATTERN LOOKS STRONG ENOUGH TO PRECLUDE
SIGNIFICANT FLOODING PROBLEMS...BUT HIGH PRECIPITATION RATES
COMBINED WITH HIGH TIDE AROUND 4 AM SUGGESTS THERE IS A RISK FOR AT
LEAST MINOR FLOODING IN THE DOWNTOWN CHARLESTON AREA PRIOR TO
SUNRISE SUNDAY.
FOR THE EARLY EVENING UPDATE...WILL INCREASE POPS ALONG THE LOWER
SOUTH CAROLINA COAST TO 60 PERCENT AND NUDGE QPF UP QUITE A BIT
BASED ON THE LATEST WPC ERP GUIDANCE. HIGHER POPS MAY BE NEEDED IN
SOME AREAS...ESPECIALLY THE CHARLESTON METRO AREA...WITH THE LATE
EVENING UPDATE DEPENDING ON HIGH RESOLUTION MODEL TRENDS.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
MONDAY...THE UPPER LOW WILL GRADUALLY RETROGRADE INLAND FROM THE
FORECAST AREA...AND THE INLAND WEDGE OF HIGH PRESSURE WILL
WEAKEN/RETREAT INLAND. AS A RESULT...THE SURFACE TROUGH OF LOW
PRESSURE IS PROGGED TO PUSH ONSHORE...ALTHOUGH THE 06/12 EUROPEAN
SOLUTION DEPICTS A MUCH SLOWER EROSION OF THE WEDGE/INLAND
PROGRESSION OF THE SURFACE TROUGH AS COMPARED WITH THE GFS/NAM.
NEVERTHELESS...THE FOCUS FOR SHOWERS/THUNDERSTORMS ALONG THE
COAST/ACROSS ADJACENT COASTAL WATERS DURING THE MORNING IS EXPECTED
TO SHIFT INLAND DURING THE AFTERNOON...EITHER ALONG THE SURFACE
TROUGH OR ALONG THE SEA BREEZE. CAPPED MAXIMUM POPS AT 50 PERCENT
IN THE MORNING NEAR THE COAST AND IN THE AFTERNOON ALONG/WEST OF
INTERSTATE 95...BUT LOCALLY GREATER POPS COULD EVENTUALLY BE
REQUIRED. PWATS AROUND 2 INCHES COULD SUPPORT LOCALLY HEAVY
RAINFALL. HOWEVER...INSTABILITY REMAINS UNIMPRESSIVE WITH CLOUDS
LIMITING HIGH TEMPS TO THE MIDDLE 80S...PERHAPS EVEN LOWER 80S
IF/WHERE SHOWERS PERSIST...SO THE POTENTIAL FOR ANY SEVERE WEATHER
REMAINS VERY LOW.
MONDAY NIGHT...INLAND SHOWERS/THUNDERSTORMS WILL GRADUALLY DISSIPATE
AS THE ENVIRONMENT COOLS/STABILIZES...AND THE FOCUS FOR OVERNIGHT
SHOWERS/THUNDERSTORMS WILL SHIFT BACK TO COASTAL COUNTIES/ADJACENT
COASTAL WATERS AS WEAK LOW-LEVEL MOISTURE TRANSPORT/MASS
CONVERGENCE DEVELOP. MODEL SIGNALS ARE NOT OVERLY IMPRESSIVE... THUS
OVERNIGHT POPS ARE CAPPED AT 30-40 PERCENT. PWATS REMAIN
ELEVATED...SO LOCALLY HEAVY RAINFALL CANNOT BE RULED OUT NEAR THE
COAST.
TUESDAY THROUGH WEDNESDAY...AT THE SURFACE THE INLAND WEDGE WILL
DISSIPATE AND WILL BE REPLACED BY ATLANTIC HIGH PRESSURE BUILDING
ONSHORE. ALOFT...THE UPPER LOW/TROUGH WILL CONTINUE TO RETROGRADE
WEST AND AWAY FROM THE FORECAST AREA...AND AN UPPER RIDGE WILL
EXPAND OVER THE REGION FROM THE SOUTHEAST. THIS WILL SUPPORT A
WARMING TREND WITH DAYTIME HIGHS IN THE UPPER 80S/LOWER 90S SHOULD
BECOME MORE COMMON AWAY FROM THE COAST...ESPECIALLY WEDNESDAY.
BETWEEN THE INLAND TROUGH AND THE COASTAL RIDGE...INCREASING
SOUTH/SOUTHWEST FLOW WILL INCREASE AND WILL USHER A POOL OF ENHANCED
MOISTURE INTO THE SOUTHEAST AS DEPICTED BY PROGS OF 850-500 MB MEAN
RH/FORECAST PWATS. THUS...AN ACTIVE CONVECTIVE REGIME SHOULD PERSIST
WITH AT LEAST SCATTERED SHOWERS/THUNDERSTORMS...NEAR THE COAST AND
ACROSS ADJACENT COASTAL WATERS BOTH MORNINGS AND EACH AFTERNOON/
EARLY EVENING ESPECIALLY INLAND. CAPPED MAXIMUM/PM POPS AT 40-50
PERCENT...BUT LOCALLY GREATER POPS COULD EVENTUALLY BE REQUIRED.
PWATS AROUND 2 INCHES COULD SUPPORT LOCALLY HEAVY RAINFALL...AND
SOMEWHAT STRONGER INSTABILITY COULD SUPPORT AN ISOLATED PULSE
THUNDERSTORM OR TWO DURING THE AFTERNOON/EARLY EVENING HOURS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE AREA WILL REMAIN BETWEEN HIGH PRESSURE OVER THE WESTERN ATLANTIC
AND A LARGE TROUGH OF LOW PRESSURE SHIFTING OVER THE CENTRAL UNITED
STATES. THE PATTERN WILL RESEMBLE ONE MORE TYPICAL DURING THE
SUMMERTIME...WITH AFTERNOON SHOWERS AND THUNDERSTORMS EACH DAY
THROUGH LATE WEEK. THE PATTERN THEN LOOKS FAIRLY ACTIVE BY THE
WEEKEND AS A COLD FRONT APPROACHES THE WEST/NORTHWEST AND SLOWLY
SHIFTS OVER THE AREA. HEAVY RAIN AND PERHAPS SOME STRONGER STORMS
WILL BE POSSIBLE. HAVE MAINTAINED CHANCES OF SHOWERS AND
THUNDERSTORMS THIS WEEKEND...BUT POPS WILL LIKELY NEED TO BE
ADJUSTED WHEN CONFIDENCE BECOMES HIGHER IN THE TIMING OF FROPA.
OVERALL HIGH TEMPS SHOULD RANGE AROUND 90 THROUGH LATE WEEK...THEN
IN THE UPPER 80S THIS WEEKEND. OVERNIGHT LOWS WILL BE IN THE LOWER
70S AWAY FROM THE COAST.
&&
.AVIATION /23Z SUNDAY THROUGH FRIDAY/...
KCHS...LOW CIGS AND RAIN IMPACTS ARE THE PRIMARY CONCERN THROUGH
SUNRISE. LATEST RAP DATA SUGGESTS IFR CIG PROBABILITIES ARE
INCREASING..ESPECIALLY 06-09Z BEFORE RAIN MOVES IN FROM OFFSHORE.
WILL SHOW SCT006 BKN010 AFTER 06Z...BUT INCREASE CIGS SLIGHTLY TO
BKN015 WITH A TEMPO GROUP 3SM RA SCT010 BKN025 FROM 09-12Z TO
ACCOUNT FOR RAIN MOVING IN FROM THE COAST. RAIN/LOW CLOUDS MAY
LINGER CLOSER TO 15Z...BUT DATA IS NOT FIRM ON THAT JUST YET.
ADJUSTMENTS WILL MOST LIKELY BE NEEDED AS CONFIDENCE INCREASES.
KSAV...LOW CIGS IS THE PRIMARY CONCERN THROUGH SUNRISE. LATEST RAP
DATA SHOW LOW CLOUDS EXPANDING ALONG THE I-95 CORRIDOR AFTER 06Z
AND LIKELY EXPANDING TO THE KSAV TERMINAL BY 07-09Z. WILL SHOW
PREVAILING IFR CIGS BY 09Z...BUT SOME ADJUSTMENTS TO THIS WILL
LIKELY BE NEEDED AS CEILING TRENDS BECOME ESTABLISHED. CIGS ARE
EXPECTED TO LIFT TO MVFR BY 13Z AND VFR BY 15Z...BUT IFR CIGS
COULD LINGER A BIT LONGER. THERE IS A POSSIBILITY THAT SHOWERS
COULD IMPACT THE TERMINAL AFTER 09Z...BUT HIGH RESOLUTION DATA
SUGGEST THE BULK OF ANY RAINFALL WILL REMAIN NORTHEAST AND EAST OF
THE TERMINAL.
EXTENDED AVIATION OUTLOOK...BRIEF FLIGHT RESTRICTIONS ARE POSSIBLE
DUE TO EARLY MORNING STRATUS/FOG AND WITHIN ANY SHOWERS/THUNDERSTORMS.
HOWEVER...VFR WILL PREVAIL MUCH OF THE TIME.
&&
.MARINE...
TONIGHT...WITH HIGH PRESSURE TO THE NORTH THE PREVAILING LOW
LEVEL FLOW WILL CONTINUE TO BE NORTHEASTERLY THROUGH MUCH OF THE
NIGHT. SPEEDS WILL CONTINUE TO BE AROUND 15 KT...AND PERHAPS INTO
THE 15-20 KT RANGE AT TIMES. THEN LATE TONIGHT...THE GRADIENT WILL
BEGIN TO RELAX AS THE COASTAL TROUGH DRIFTS CLOSER TO SHORE.
SPEEDS WILL DROP OFF MORE INTO THE 10-15 KT RANGE THROUGH SUNRISE.
SEAS WILL BE 2-4 FT THROUGH MUCH OF THE NIGHT AND WILL BEGIN TO
COME DOWN INTO THE 2-3 FT RANGE LATE AS WINDS DIMINISH.
MONDAY THROUGH FRIDAY...EARLY THIS WEEK THE INLAND WEDGE OF HIGH
PRESSURE WILL WEAKEN AND DISSIPATE...THE COASTAL TROUGH WILL PUSH
ONSHORE AND WILL DISSIPATE...AND ATLANTIC HIGH PRESSURE WILL BUILD
WEST OVER THE WATERS. AS THIS TRANSITION OCCURS...NE WINDS 10-15 KT
MONDAY WILL VEER TO THE E/SE AROUND 10 KT MONDAY NIGHT THROUGH
TUESDAY...THEN WINDS WILL VEER TO THE S/SW AT 15 KT OR LESS TUESDAY
NIGHT THROUGH THURSDAY. SEAS OF 1-3 FT WILL PREVAIL...HIGHEST BEYOND
20 NM.
WINDS/SEAS WILL THEN GRADUALLY INCREASE/BUILD LATE WEEK AS THE
GRADIENT BECOMES ENHANCED WITH A TROUGH OF LOW PRESSURE APPROACHING
FROM THE WEST/NORTHWEST. HOWEVER...CONDITIONS ARE EXPECTED TO REMAIN
BELOW SMALL CRAFT ADVISORY LEVELS.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
ST
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
104 AM CDT SAT SEP 5 2015
.SHORT TERM...
235 PM CDT
THROUGH SATURDAY NIGHT...
SHOWERS AND THUNDERSTORMS HAVE BEEN MOST CONCENTRATED...BUT STILL
LARGELY SCATTERED...IN NORTHWEST INDIANA...AND EAST INTO EASTERN
ILLINOIS BUT WELL SOUTH...CLOSER TO A REMNANT FRONTAL BOUNDARY FROM
LAST NIGHT THAT STALLED OUT SOMEWHERE IN THE ROCHELLE TO JOLIET TO
VALPARAISO LINE. MOST OF THIS ACTIVITY HAS CONTINUED EAST. THIS
BOUNDARY STILL REMAINS...BUT WE ALSO NOW HAVE A LAKE BREEZE BOUNDARY
THAT IS NOW MAKING STEADY BUT NOW SLOWING INLAND PROGRESS THIS
AFTERNOON. THIS COMBINED WITH UPPER LEVEL LOW PRESSURE ATOP THE AREA
1500-2500 J/KG OF MIXED LAYER CAPE AWAY FROM THE LAKE IS RESULTING
IN ADDITIONAL ISOLATED DEVELOPMENT THIS AFTERNOON. THE BETTER
INSTABILITY AND CONVERGENCE SLIGHTLY COOLER TEMPS ALOFT STILL RESIDE
FROM THE KANKAKEE RIVER EASTWARD WILL ADDITIONAL DEVELOPMENT WILL
LIKELY CONTINUE. THESE STORMS STILL POSE A HEAVY RAINFALL THREAT IF
THEY CAN CONGEAL AS THEY ARE SLOW MOVING...WITH A LOW CONCERN FOR
GUSTY WINDS IN FORD/IROQUOIS COUNTY ILLINOIS INTO
BENTON/NEWTON/JASPER COUNTIES OF INDIANA...WITH THE HIGHER
CONCERN EAST INTO CENTRAL INDIANA.
LIKE YESTERDAY...THE LOSS OF DAYTIME HEATING...WE SHOULD SEE
ACTIVITY DIMINISH QUICKLY. THE UPPER LOW LINGERS IN THE REGION
OVERNIGHT. ANOTHER WEAK WAVE WILL ATTEMPT TO MOVE INTO THE UPPER
LEVEL RIDGE THAT WILL BUILD IN FROM THE WEST OVERNIGHT. MANY
GUIDANCE MEMBERS SUGGEST THAT THIS COUPLED WITH SOME RAMPING UP OF
ISENTROPIC LIFT AHEAD OF THIS FEATURE MAY TRIGGER SOME ISOLATED
SHOWERS OR THUNDERSTORMS LATE TONIGHT INTO EARLY SATURDAY. HAVE
MOVED TOWARD THE DRIER NAM SOLUTION AT THIS POINT IN TIME WHICH IS
REFLECTED IN THE EXPERIMENTAL HRRR AND HI-RES NMM/ARW AS WE DO NOT
FEELING FORCING IS STRONG ENOUGH TO TAP INTO ANY ELEVATED
INSTABILITY BUT WILL BE A PERIOD TO WATCH.
THE UPPER RIDGE IS OVER WESTERN ILLINOIS...WITH THE UPPER LOW
INCHING EASTWARD. LOW LEVEL SOUTHWESTERLIES SHOULD ALLOW WARMING ALL
THE WAY TO THE LAKEFRONT WITH 90S INLAND AND UPPER 80S AT THE LAKE.
A WEAKENING OF THE PRESSURE GRADIENT NEAR THE LAKE WOULD SUPPORT A
SE WIND SHIFT NEAR THE LAKE LATER IN THE DAY TO SUPPORT SOME
COOLING. HEAT INDICES WILL GET INTO THE MID TO UPPER 90S IN MANY
SPOTS. HAVE HELD ONTO THE SLIGHT CHANCE POPS FOR TOMORROW
AFTERNOON GIVEN THE MOIST/UNSTABLE ENVIRONMENT...BUT AT THIS POINT
MOST AREAS LOOK TO REMAIN DRY AS THE MAIN TRIGGER IS LACKING.
KMD
&&
.LONG TERM...
SUNDAY THROUGH FRIDAY...
300 PM...MULTIPLE FORECAST CONCERNS INCLUDING HIGH TEMPS SUNDAY
AND MONDAY...PRECIP CHANCES/TIMING LATE SUNDAY NIGHT THRU
WEDNESDAY ALONG WITH HEAVY RAIN POTENTIAL MONDAY NIGHT/TUESDAY.
UPPER RIDGE WILL BE RIGHT OVER THE AREA SUNDAY WITH DRY WEATHER AND
MOSTLY SUNNY SKIES. THIS SHOULD ALLOW TEMPS TO EASILY REACH THE
LOWER 90S INCLUDING ALONG MUCH OF THE IL LAKESHORE AS SOUTHWESTERLY
WINDS APPEAR STRONG ENOUGH THRU MID AFTERNOON TO PREVENT A LAKE
BREEZE. AS THE WINDS DIMINISH IN THE LATER AFTERNOON...WINDS WILL
LIKELY TURN SOUTHEASTERLY ALONG THE IL SHORE COOLING TEMPS A BIT.
WITH DEWPOINTS IN THE UPPER 60S/LOWER 70S...AFTERNOON HEAT INDEX
VALUES COULD CLIMB INTO THE UPPER 90S.
A FRONTAL BOUNDARY WILL MOVE SOUTHEAST ACROSS THE MIDWEST AND
WESTERN LAKES REGION SUNDAY NIGHT REACHING THE AREA MONDAY MORNING.
THE SLOWER TIMING FROM 24 HOURS AGO HAS HELD WITH THE MOST RECENT
GUIDANCE WITH MUCH OF THE AREA STAYING DRY UNTIL EARLY MONDAY
MORNING AND THE BEST CHANCES FOR PRECIP ACROSS NORTHWEST IL TOWARD
DAYBREAK. IT STILL APPEARS THAT PRECIP WILL BE DISSIPATING MONDAY
MORNING BUT TO WHAT EXTENT IS UNCERTAIN. HAVE INTRODUCED MORE OF A
GRADIENT WITH POPS DROPPING OFF TO SLIGHT CHANCE ACROSS THE
SOUTHEAST. POSSIBLE ADDITIONAL DEVELOPMENT MAY OCCUR LATER IN THE
AFTERNOON/EARLY EVENING. PRECIP COVERAGE AND ASSOCIATED CLOUD COVER
MAKE FOR A TRICKY TEMP FORECAST. STILL POSSIBLE TEMPS MAY CLIMB TO
NEAR 90 ACROSS THE SOUTHEAST MONDAY AFTERNOON.
THIS FRONTAL BOUNDARY THEN SLOWS AND STALLS ACROSS THE REGION MONDAY
NIGHT INTO TUESDAY AS AN UPPER WAVE LIFTS NORTHEAST ACROSS THE AREA.
WITH MOISTURE POOLING ALONG THIS BOUNDARY...PERIODS OF HEAVY RAIN
WITH THUNDERSTORMS IS LIKELY SOMEWHERE ACROSS THE REGION...A BIT
EARLY FOR SPECIFICS AND LOCATIONS. AS A STRONGER COLD FRONT MOVES
ACROSS THE AREA TUESDAY INTO TUESDAY NIGHT...THIS SHOULD PUSH THE
PRECIP CHANCES SOUTH OF THE AREA BUT STILL SOME UNCERTAINTY AS TO
HOW FAST THIS OCCURS. ANOTHER WAVE MOVES ACROSS THE AREA LATE NEXT
WEEK AS A LARGE UPPER TROUGH IS PROGGED TO MOVE ACROSS THE LAKES
REGION. GFS/ECMWF HAVE BEEN SHOWING THIS FOR SOME TIME...BUT IT
CONTINUES TO BE DELAYED. IF/WHEN THIS FINALLY ARRIVES...MUCH COOLER
TEMPS AND MUCH LOWER HUMIDITY WITH SPREAD ACROSS THE REGION. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* POSSIBLE PATCHY FOG EARLY THIS MORNING...MAY REDUCE VSBYS.
MAINLY WEST OF ORD/MDW.
* ISOLATED STORMS POSSIBLE EARLY THIS AFTERNOON...COVERAGE WILL
REMAIN LOW.
* LIGHT SOUTHWEST TO SOUTH WINDS...MAY ALLOW WINDS TO TURN
SOUTHEAST FROM A LAKE BREEZE CLOSER TO MDW AND POSSIBLY ORD
LATE IN THE AFTN.
BEACHLER
//DISCUSSION...UPDATED 06Z...
UPPER LEVEL SYSTEM CONTINUES TO ROTATE OVER THE GREAT LAKES
REGION...WITH A VERY LIGHT GRADIENT. THIS HAS ALLOWED WARM/HUMID
AIR TO FLOW NORTH. WITH LIGHT WINDS EARLY THIS MORNING AND VERY
MOIST ENVIRONMENT...PATCHY FOG MAY BEGIN TO DEVELOP. VSBYS COULD
BECOME REDUCED TO ARND 3-4SM...AND POSSIBLY FURTHER REDUCTIONS
WELL WEST OF THE METRO AREA.
A WEAK AREA OF FORCING WILL FLOAT OVERHEAD AFTER DAYBREAK AND
COULD TOUCH OFF AN ISOLATED SHOWER/THUNDERSTORM FOR FAR
WEST/NORTHWEST IL THRU MID-MORNING. THEN THIS AREA WILL
WEAKEN...WITH SEVERAL HI-RESOLUTION GUIDANCE INDICATING ADDITIONAL
ISOLATED SHOWERS OR STORMS DEVELOPING AFTER 18Z. SINCE COVERAGE IS
EXPECTED TO BE SO LOW AND EVEN THE CONFIDENCE IS LOW THAT IT WOULD
IMPACT THE AIRFIELDS...HAVE OPTED TO PULL THE PROB30 GROUP AND
LIMIT WITH A VCSH. THIS MAY NEED TO BE REVISED LATER THIS MORNING
AS CONFIDENCE COULD INCREASE WITH RESPECT TO TIMING/COVERAGE.
WINDS WILL GENERALLY REMAIN LIGHT OR LESS THAN 8KT FROM THE
SOUTHWEST...THEN BEGIN TO TURN SOUTHERLY LATER THIS MORNING. THE
GRADIENT SHOULD REMAIN LIGHT ENOUGH TO ALLOW WINDS TO TURN
SOUTHEAST AND COULD BECOME ONSHORE LATE THIS AFTERNOON FOR
MDW/ORD FROM A LAKE BREEZE.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN WIND DIR/SPEED...MEDIUM CONFIDENCE IN LAKE
BREEZE DEVELOPING.
* HIGH CONFIDENCE IN ISOLATED SHOWERS/THUNDERSTORMS
DEVELOPING...BUT VERY LOW CONFIDENCE IN TIMING/COVERAGE.
* MEDIUM CONFIDENCE IN EARLY MORNING VSBY FORECAST.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...VFR LIKELY. SOUTH WINDS.
MONDAY...CHANCE OF TSRA. SOUTHWEST WINDS.
TUESDAY...TSRA LIKELY. SOUTHWEST WINDS.
WEDNESDAY...CHANCE OF TSRA. NORTHEAST WINDS.
THURSDAY...SLIGHT CHANCE OF SHRA. NORTH WINDS.
MTF
&&
.MARINE...
315 PM...THE GRADIENT WILL SLOWLY TIGHTEN ACROSS LAKE MICHIGAN
THIS WEEKEND AS A LARGE TROUGH OF LOW PRESSURE OVER THE PLAINS
MOVES EAST WITH HIGH PRESSURE REMAINING OVER THE EASTERN U.S.
SOUTHERLY WINDS WILL LIKELY INCREASE INTO THE 15-25 KT RANGE ON
SUNDAY ESPECIALLY OVER THE NORTHERN PORTION OF THE LAKE. A COLD
FRONT WILL MOVE ACROSS THE LAKE MONDAY AFTERNOON INTO MONDAY
EVENING BUT THIS FRONT WILL SLOW AND STALL ACROSS THE SOUTHERN
LAKES REGION WITH WINDS TURNING BACK SOUTHERLY AHEAD OF ANOTHER
APPROACHING COLD FRONT THAT ARRIVES THURSDAY OR THURSDAY NIGHT
THOUGH CONFIDENCE REGARDING TIMING REMAINS LOW. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS DES MOINES IA
624 PM CDT SUN SEP 6 2015
.SHORT TERM /TONIGHT/...
ISSUED AT 305 PM CDT SUN SEP 6 2015
STILL SOME UNCERTAINTY ABOUT EVOLUTION OF SYSTEM TONIGHT. VARIOUS
MODEL SOLUTIONS BEGINNING TO EITHER POINT TOWARD SLIGHTLY MORE
PROGRESSIVE EVOLUTION OF CONVECTION OVERNIGHT...OR SLIGHTLY MORE
NORTH PLACEMENT OF MAX.
SO FAR CONVECTIVE TRENDS HAVE BEEN RAMPING UP SLOWLY DUE TO H700
TEMPS SITTING ABOVE 11-12C THIS AFTERNOON. BUT AS FRONT ENTERS
NW/W IA EARLY THIS EVENING AND AREA BECOMES UNCAPPED AND H700
TEMPS COOL A COUPLE OF DEGREES...A RAPID INCREASE IN STORMS SHOULD
OCCUR BETWEEN 4 PM AND 7 PM. DESPITE THE EXPECTED MODEL
UNCERTAINTY...WE ARE IN NEAR RECORD TERRITORY FOR AVAILABLE
ATMOSPHERIC MOISTURE FOR EARLY SEPTEMBER. THIS IS DUE IN PART TO A
PROLONGED FETCH OF GULF MOISTURE WHICH IS FEEDING NORTHEAST INTO
THE CENTRAL PLAINS AND GREAT LAKES. SECONDLY...A TROPICAL
CONNECTION FROM THE SOUTHWEST US THAT RESULTED IN AN OLD TROPICAL
SYSTEM EARLIER IN THE WEEK OFF THE COAST OF BAJA MEXICO BEING
INGESTED IN THE MID TO UPPER LEVEL FLOW. PWAT VALUES WILL BE
APPROACHING 2 TO 2.25 INCHES BETWEEN 00-06Z TONIGHT PLACING OUR
VALUES IN THE 99TH/100TH PERCENTILE AND OVER 3 SDEV ABOVE NORMAL
FOR THIS TIME OF YEAR. WARM CLOUD DEPTHS ARE NEAR 14.5KFT WHICH IS
EXTREMELY DEEP. THERE REMAIN NUMEROUS FACTORS SUPPORTING
EFFICIENT/HIGH RAINFALL RATES THIS EVENING...AND LOOKING
AHEAD...AGAIN MONDAY NIGHT. BACK TO THE MODELS...CONSECUTIVE RUNS
OF THE HRRR ARE SHOWING A MORE PROGRESSIVE EVOLUTION TO TONIGHTS
CONVECTION WITH FORWARD PROPAGATING CORFIDI VECTORS ABOUT 20 KTS.
BUT EVEN THIS IS DECEIVING IF RAINFALL RATES ARE 2-3 INCHES PER
HOUR AT TIMES...AND STILL SUGGESTS A QUICK COUPLE OF INCHES OF
RAIN IN THE MORE VIGOROUS CELLS. WITH ANY LOCALIZED
TRAINING...STILL A POTENTIAL FOR ISOLATED 3 TO 4 INCHES AMOUNTS
OVERNIGHT. THE NAM IS LEANING TOWARD THE MORE PROGRESSIVE HRRR
OVERNIGHT WITH THE GFS RAMPING UP CONVECTION BETWEEN 00-06Z ON THE
NOSE OF THE INCREASING LOW LEVEL JET ALONG THE INVERTED TROUGH
WITHIN THE ZONE OF MAXIMUM SFC CONVERGENCE. THE QPF MAX IS
CENTERED OVER HIGHWAY 30...ROUGHLY BETWEEN US 20/I80 FROM GREENE
TO MARSHALL COUNTIES. WITH THAT ADDED UNCERTAINTY TONIGHT AND THE
POSSIBLE NORTHERLY SHIFT BY 20 MILES OF THE QPF MAX...WILL BE
ADDING ONE ROW OF COUNTIES TO TONIGHTS FFA ALONG US 20. REALIGNING
THE WATCH NOW IS RISKY...DUE TO THE POSSIBILITY OF THE MODELS ARE
NOT PROPERLY ACCOUNTING FOR A STRONGER OUTFLOW BOUNDARY LATER IN
THE EVENING...WHICH WOULD THEN BE FEEDING OFF AN INCREASING LOW
LEVEL JET OVERNIGHT. THERE MAY ACTUALLY BE TWO FAVORED AREAS OF
HEAVY RAINFALL...EARLIER BETWEEN US20/30 AND LATER ALONG AND SOUTH
OF I80. NONE THE LESS...THE RISK FOR FLASH FLOODING AND SUBSEQUENT
ISSUES REMAINS. TIMING OF THE EVENT SUGGESTS THAT STORMS SHOULD BE
IN FULL SWING BETWEEN 02-09Z WITH ACTIVITY REMAINING STRONG BUT
SLOWLY DIMINISHING BETWEEN 09-13Z MONDAY OVER THE SOUTH/SOUTHEAST.
LOWS TONIGHT WILL FALL TO THE LOWER 70S SOUTH TO NEAR 60 OVER THE
FAR NORTHWEST AS THE COOLER AIR BEGINS TO FILTER INTO THE REGION
TONIGHT. TONIGHTS RAINFALL WILL PRIME THE REGION FOR A MORE
SIGNIFICANT RISK OF FLOODING MONDAY NIGHT AND THIS IS COVERED IN
THE EXTENDED DISCUSSION.
.LONG TERM /MONDAY THROUGH SUNDAY/...
ISSUED AT 305 PM CDT SUN SEP 6 2015
A POTENTIALLY SIGNIFICANT HEAVY RAIN AND FLOODING EVENT MAY BE
SHAPING UP EARLY THIS WEEK.
THE COLD FRONT SAGGING DOWN INTO IOWA TONIGHT...AS DISCUSSED IN
THE SHORT TERM SECTION ABOVE...WILL LIKELY STALL ACROSS SOUTHERN
IOWA BY MONDAY MORNING THEN RETREAT BACK NORTHWARD A BIT TOWARD
CENTRAL IOWA DURING THE DAY. DESTABILIZATION WILL BE LIMITED BY
DEBRIS CLOUDS AND A LACK OF LOW LEVEL WARM AIR ADVECTION OVER
MOST OF THE FORECAST AREA...PLUS THERE WILL BE NO LARGE SCALE
FORCING MECHANISM FOR CONVECTION FOR MOST OF THE DAY. NEVERTHELESS
THE AIRMASS WILL BE JUICED ENOUGH WITH THE BOUNDARY WOBBLING
AROUND THAT LOW POPS ARE MAINTAINED ON MONDAY.
BEGINNING LATE MONDAY AFTERNOON AND ESPECIALLY ON MONDAY NIGHT THE
ATMOSPHERE APPEARS TO BE SETTING UP FOR A SIGNIFICANT...POSSIBLY
EXTREME HEAVY RAINFALL EVENT. ALONG AND SOUTH OF THE NEARLY
STATIONARY FRONTAL ZONE PWAT VALUES WILL BE NEAR RECORDS WITH
SUBSTANTIAL MOISTURE TRANSPORT CONTINUING FROM THE GULF ESPECIALLY
AS THE NOCTURNAL LOW LEVEL JET KICKS IN AFTER DARK.
CONCURRENTLY...A SECOND FAIRLY ROBUST MID LEVEL SHORTWAVE WILL
ROUND THE BASE OF BROAD CYCLONIC FLOW ALOFT AND PROVIDE A TRIGGER
FOR WIDESPREAD THUNDERSTORM DEVELOPMENT. WITH WARM CLOUD DEPTHS IN
EXCESS OF 15 KFT IN FORECAST SOUNDINGS AND THE COMBINATION OF
OTHER FACTORS...WE WILL BE PRIMED FOR VERY EFFICIENT RAINFALL
RATES AND POTENTIALLY TRAINING OR SLOW MOVING STORMS NEAR THE
FRONTAL ZONE. THIS COULD LEAD TO WIDESPREAD RAINFALL AMOUNTS IN
THE 2 TO 3 INCH RANGE WITHIN A BROAD SWATH ACROSS THE AREA...AND
LOCALIZED AMOUNTS OF 6 INCHES OR MORE ARE DEFINITELY CONCEIVABLE.
IN TERMS OF THE FLOODING EFFECTS OF SUCH RAINFALL...MUCH WILL
DEPEND ON WHERE IT FALLS AND WHETHER IT OCCURS IN THE SAME AREA AS
THE HEAVIEST RAINFALL TONIGHT...WHICH IS IN TURN DEPENDENT ON THE
DIFFICULT TO PREDICT MOTIONS AND LOCATION OF THE FRONTAL BOUNDARY
BY MONDAY EVENING. IT IS LIKELY...IN ANY EVENT...THAT A SECOND
FLASH FLOOD WATCH WILL BE NEEDED AFTER TONIGHTS RAINFALL PANS
OUT...AND THAT IT MAY NEED TO HAVE EVEN STRONGER WORDING FOR THE
POTENTIAL EFFECTS MONDAY NIGHT INTO TUESDAY MORNING.
SCATTERED THUNDERSTORMS MAY CONTINUE TO FESTER ACROSS OUR SOUTHERN
COUNTIES ON TUESDAY AS THE FRONTAL ZONE LINGERS NEAR THE
IOWA/MISSOURI BORDER...BUT THEN ANOTHER SHORTWAVE TROUGH WILL MOVE
OVERHEAD AROUND TUESDAY EVENING AND FINALLY CLEAR OUT THE WET
AIRMASS TO OUR SOUTH. THIS WILL BRING AN END OF ANY HEAVY RAIN
THREAT FOR THE REMAINDER OF THE SEVEN DAY FORECAST...ALONG WITH
NOTABLY COOLER AND DRIER WEATHER ACROSS IOWA. THERE WILL BE A
CHANCE FOR SCATTERED SHOWERS AND STORMS AROUND THURSDAY AS A
REINFORCING COLD FRONT SURGES ACROSS THE STATE...USHERING IN THE
FIRST TRULY AUTUMNAL WEATHER OF THE SEASON AT THE END OF THIS WEEK
WITH FRIDAY HIGHS IN THE 60S AND FRIDAY NIGHT LOWS IN THE 40S
STATEWIDE.
&&
.AVIATION...07/00Z
ISSUED AT 624 PM CDT SUN SEP 6 2015
LINE OF THUNDERSTORMS STRETCHING FROM KDNS TO KMCW TO CONTINUE TO
MOVES ESE THROUGH THE STATE DURING THE EVENING AND OVERNIGHT
HOURS. LOW CLOUDS AND SOME FOG POSSIBLE ACROSS THE NORTHERN TAFS
BEHIND THE THUNDERSTORMS. MVFR TO POSSIBLY IFR VSBYS POSSIBLE WITH
THE STORMS IN ESPECIALLY OVERNIGHT DUE TO HEAVY RAINFALL. HAIL
ALSO POSSIBLE AND DAMAGING WINDS WITH ANY POTENTIAL SEVERE STORMS.
&&
.HYDROLOGY...
ISSUED AT 305 PM CDT SUN SEP 6 2015
AS REFERENCED IN THE PREVIOUS DISCUSSIONS...TWO HEAVY
RAINFALL EVENTS ARE POSSIBLE TONIGHT THROUGH TUESDAY MORNING WITH
THE FOCUS FROM NORTH CENTRAL TO SOUTHERN IOWA. WIDESPREAD RAINFALL
AMOUNTS OF 2 TO 3 INCHES ARE EXPECTED WITH AMOUNTS EXCEEDING 5
INCHES POSSIBLE DURING THIS PERIOD. MONDAY NIGHTS EVENT IS STILL
EXPECTED TO BE OF GREATER MAGNITUDE...SO SOME REEVALUATION OF THE
WATCH OUTLINE WILL OCCUR BETWEEN THIS EVENING AND TOMORROW
MORNING AFTER TONIGHTS RAINFALL REPORTS ARE GATHERED. IN BOTH
EVENTS...EFFICIENT RAIN PRODUCING STORMS WILL PRODUCE HEAVY
RAINFALL OVER A SHORT PERIOD OF TIME. SIGNIFICANT RUNOFF AND/OR
PONDING OF WATER IS LIKELY IN SOME AREAS LEADING TO A FLASH FLOOD
THREAT. THE EVENT MAY EVOLVE INTO A RIVER FLOODING THREAT THROUGH
MID TO LATE WEEK AS THE RUNOFF REACHES THE LARGER STREAMS. THE
MAGNITUDE OF RIVER FLOODING ON ANY GIVEN MAINSTEM RIVER WILL
DEPEND ON BOTH RAINFALL AMOUNTS AND BASIN COVERAGE IN THE NEXT 48
TO 60 HOURS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH MONDAY MORNING FOR ADAIR-ADAMS-
APPANOOSE-AUDUBON-BLACK HAWK-BOONE-CASS-CLARKE-DALLAS-DAVIS-
DECATUR-GREENE-GRUNDY-GUTHRIE-HAMILTON-HARDIN-JASPER-LUCAS-
MADISON-MAHASKA-MARION-MARSHALL-MONROE-POLK-POWESHIEK-RINGGOLD-
STORY-TAMA-TAYLOR-UNION-WAPELLO-WARREN-WAYNE.
&&
$$
SHORT TERM...REV
LONG TERM...LEE
AVIATION...BEERENDS
HYDROLOGY...REV
AREA FORECAST DISCUSSION
NWS TOPEKA KS
937 PM CDT SUN SEP 6 2015
...Update to near-term forecast...
.UPDATE...
ISSUED AT 933 PM CDT SUN SEP 6 2015
Convective development in the local forecast area continues to
struggle, but a rather strong model signal continues to indicate
that elevated storms (similar to that currently seen in far
southeast Nebraska) will develop into eastern KS as well tonight.
It seems that for this to occur depends on the development of a
cold pool from the ongoing storms. This currently exists near the
Nebraska border, and if it can continue to be reinforced and
pushed south than would expect at least scattered storms to
develop overnight. If this happens, the severe weather threat is
quite low but non-zero for wind/hail. Pockets of heavy rain also
remain possible if these storms develop as there could be
localized training, but dry ground conditions suggest the flash
flood potential is quite low.
&&
.SHORT TERM...(THIS EVENING THROUGH Monday)
ISSUED AT 254 PM CDT SUN SEP 6 2015
Latest surface analysis had the frontal boundary from just east of
Albion Nebraska to near Norton Kansas at 19Z. Surface temperatures
ahead of the front across northeast Kansas have warmed to near the
century mark in north central and northeast Kansas. Latest
mesoanalysis along with latest RAP soundings show steep low level
lapse rates and SBCAPE around 3000 J/kg this afternoon. Hires
short term models have differing scenarios with regards to
convective development, with the operational HRRR and the RAP the
most robust with developing storms where the ARW, NMM and
experimental HRRR showing less coverage across central and north
central Kansas tonight. However most models continue to show a
signal of a MCS developing across far northeast Kansas into
southwest Iowa and northwest Missouri tonight and then moving it
south southeast across eastern Kansas and western Missouri. The
aforementioned frontal boundary will gradually move eastward
tonight into the forecast area. Not sure exactly how far south the
boundary will move tonight before lifting north again on Labor
Day. Water vapor loop this afternoon shows moisture streaming from
the eastern Pacific into the Central Plains. Southwesterly low
level jet will advect high theta-e air into northeast Kansas
overnight and should help to maintain the forward propagating MCS
as well as contribute to high precipitation efficiency. On Labor
day the front is expected to lift northward in response to an
upper level trough moving eastward into the Northern and Central
Plains to near or just north of the Nebraska and Kansas border in
the afternoon. Left over boundaries from morning convection may
focus isolated convection in the afternoon, but feel most areas
will be dry until late afternoon along the Kansas and Nebraska
border near the front. Effective shear tonight and Labor Day will
be around 25 to 30 kts along with ample instability. If storms
develop late this afternoon and early evening they will have the
potential for damaging wind gusts and also again on Labor Day
afternoon. There is also some potential for Hail as storms become
elevated later tonight, but locally heavy rainfall will be the
main concern. Lows tonight remain mild in the low to mid 70s and
highs on Labor Day will be dependent on cloud cover. Feel there
may be enough sunshine to send temps back into the lower 90s for
most areas.
.LONG TERM...(Monday NIGHT THROUGH Sunday)
ISSUED AT 254 PM CDT SUN SEP 6 2015
Monday night through Wednesday...Synoptic scale boundary should
extend from southeast Nebraska through north central KS by early
Monday evening. As boundary sags slowly south over night, expect
clusters of thunderstorms to develop along it and move east, with
the best chance for heavier rainfall north of I70, and especially
near and north of U.S. 36. Have highest POPs and most QPF for that
area. On Tuesday, most short term models bring frontal boundary
nearly through the forecast area, although outflow from
thunderstorm complex makes it somewhat hard to place. Highest POPs
should shift from northeast KS into far eastern, and especially
east central KS during the afternoon. Thunderstorm activity near
the front should shift out of east central KS during the evening.
Would expect late Tuesday night and Wednesday to be dry as a ridge
of surface high pressure builds in.
Wednesday night through Sunday...Eastern KS remains in northwest
flow aloft through Saturday. While gulf airmass should remain to
our south, periodic disturbances in this northwest flow will
result in chances for showers and thunderstorms. Cooler, more
stable airmass over far northeast KS is expected to keep the
best chance for convective activity over north central and parts
of east central KS. Much cooler temperatures than we`ve had
recently are expected for the latter part of the week into the
weekend, with highs in the 70s to lower 80s, depending on how much
sun is seen each afternoon.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z Monday EVENING)
ISSUED AT 620 PM CDT SUN SEP 6 2015
A difficult forecast over the next 12 hours regarding thunderstorm
chances and associated wind shifts at TAF sites. Current thinking
is that TS coverage will not be widespread, but may impact any of
the TAF sites and have highlighted the most likely timing with a
TS group. VFR conditions would be likely through the TAF, even
with thunderstorms, although brief periods of gusty and variable
winds along with briefly reduced vis with heavy rain would be
possible if TS impact the sites.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Barjenbruch
SHORT TERM...53
LONG TERM...GDP
AVIATION...Barjenbruch
AREA FORECAST DISCUSSION
NWS TOPEKA KS
628 PM CDT SUN SEP 6 2015
...Update to near term convective, and aviation forecast
discussions...
.UPDATE...
ISSUED AT 620 PM CDT SUN SEP 6 2015
Convection has developed in north central KS, but struggled a bit
initially. Winds ahead of the incoming cold front have backed out
of the southeast slightly in the past hour or two and seem to be
enhancing convergence along and just ahead of the boundary. This
seems to be giving storms a more consistent lift to the LFC, and
have seen a slight strengthening trend recently in an atmosphere
characterized by around 2000 J/kg of SBCAPE and less than 30 kts
of effective shear. The primary hazard in this environment will be
localized damaging downburst winds as storms intensify and then
collapse into the near 100 degree surface air. This threat should
also be mainly limited to the pre-10 PM time frame...although not
completely ruled out later in the night.
&&
.SHORT TERM...(THIS EVENING THROUGH Monday)
ISSUED AT 254 PM CDT SUN SEP 6 2015
Latest surface analysis had the frontal boundary from just east of
Albion Nebraska to near Norton Kansas at 19Z. Surface temperatures
ahead of the front across northeast Kansas have warmed to near the
century mark in north central and northeast Kansas. Latest
mesoanalysis along with latest RAP soundings show steep low level
lapse rates and SBCAPE around 3000 J/kg this afternoon. Hires
short term models have differing scenarios with regards to
convective development, with the operational HRRR and the RAP the
most robust with developing storms where the ARW, NMM and
experimental HRRR showing less coverage across central and north
central Kansas tonight. However most models continue to show a
signal of a MCS developing across far northeast Kansas into
southwest Iowa and northwest Missouri tonight and then moving it
south southeast across eastern Kansas and western Missouri. The
aforementioned frontal boundary will gradually move eastward
tonight into the forecast area. Not sure exactly how far south the
boundary will move tonight before lifting north again on Labor
Day. Water vapor loop this afternoon shows moisture streaming from
the eastern Pacific into the Central Plains. Southwesterly low
level jet will advect high theta-e air into northeast Kansas
overnight and should help to maintain the forward propagating MCS
as well as contribute to high precipitation efficiency. On Labor
day the front is expected to lift northward in response to an
upper level trough moving eastward into the Northern and Central
Plains to near or just north of the Nebraska and Kansas border in
the afternoon. Left over boundaries from morning convection may
focus isolated convection in the afternoon, but feel most areas
will be dry until late afternoon along the Kansas and Nebraska
border near the front. Effective shear tonight and Labor Day will
be around 25 to 30 kts along with ample instability. If storms
develop late this afternoon and early evening they will have the
potential for damaging wind gusts and also again on Labor Day
afternoon. There is also some potential for Hail as storms become
elevated later tonight, but locally heavy rainfall will be the
main concern. Lows tonight remain mild in the low to mid 70s and
highs on Labor Day will be dependent on cloud cover. Feel there
may be enough sunshine to send temps back into the lower 90s for
most areas.
.LONG TERM...(Monday NIGHT THROUGH Sunday)
ISSUED AT 254 PM CDT SUN SEP 6 2015
Monday night through Wednesday...Synoptic scale boundary should
extend from southeast Nebraska through north central KS by early
Monday evening. As boundary sags slowly south over night, expect
clusters of thunderstorms to develop along it and move east, with
the best chance for heavier rainfall north of I70, and especially
near and north of U.S. 36. Have highest POPs and most QPF for that
area. On Tuesday, most short term models bring frontal boundary
nearly through the forecast area, although outflow from
thunderstorm complex makes it somewhat hard to place. Highest POPs
should shift from northeast KS into far eastern, and especially
east central KS during the afternoon. Thunderstorm activity near
the front should shift out of east central KS during the evening.
Would expect late Tuesday night and Wednesday to be dry as a ridge
of surface high pressure builds in.
Wednesday night through Sunday...Eastern KS remains in northwest
flow aloft through Saturday. While gulf airmass should remain to
our south, periodic disturbances in this northwest flow will
result in chances for showers and thunderstorms. Cooler, more
stable airmass over far northeast KS is expected to keep the
best chance for convective activity over north central and parts
of east central KS. Much cooler temperatures than we`ve had
recently are expected for the latter part of the week into the
weekend, with highs in the 70s to lower 80s, depending on how much
sun is seen each afternoon.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z Monday EVENING)
ISSUED AT 620 PM CDT SUN SEP 6 2015
A difficult forecast over the next 12 hours regarding thunderstorm
chances and associated wind shifts at TAF sites. Current thinking
is that TS coverage will not be widespread, but may impact any of
the TAF sites and have highlighted the most likely timing with a
TS group. VFR conditions would be likely through the TAF, even
with thunderstorms, although brief periods of gusty and variable
winds along with briefly reduced vis with heavy rain would be
possible if TS impact the sites.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Barjenbruch
SHORT TERM...53
LONG TERM...GDP
AVIATION...Barjenbruch
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1222 PM CDT SAT SEP 5 2015
...Update to aviation forecast discussion...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 231 AM CDT SAT SEP 5 2015
Not much change to the overall pattern with southwest flow aloft
over the central and southern plains keeping the lee side trough in
place and a decent pressure gradient across eastern KS. Temperatures
will be a few degrees higher today so expect highs in the low to mid
90s with a few locations possibly reaching the upper 90s in central
KS. Southerly winds will again increase later today around 15 to 25
mph with gusts up to 35 mph. Later this morning a weak shortwave
will track over western NE and support showers and storms possibly
as far east as north central KS. The latest runs of the HRRR are now
hinting at isolated development in that area around sunrise, but
decided not to increase pops given the low uncertainty. The models
are showing mid level moisture spreading northward from the gulf
today coupled with cooler 850 mb temperatures across southeast KS.
This may lead to a weaker cap and an isolated shower or storm could
be possible south of I-35 this afternoon as daytime heating erodes
this cap. There is no obvious mid level support or any other focus
for lift so did not increase pops, but it could not be completely
ruled out. Tonight a cold front will drift eastward through the high
plains while several weak mid-level shortwaves track over the same
area. This should support storm development along the front in NE
during the overnight hours although have kept the northern forecast
area dry through sunrise.
.LONG TERM...(Sunday THROUGH Friday)
ISSUED AT 231 AM CDT SAT SEP 5 2015
Front still advancing across the Northern Plains on Sunday and
just starts to move into the far northwestern CWA by the late
afternoon hours. This leaves much of the area parked under the
thermal ridge for Sunday, with temperatures rising well into the
middle 90s. Heat indicies look to range from near 100 to 102F by
the afternoon hours. Northern counties may get some relief
overnight as front moves southward about halfway across the CWA,
but stalls out without a strong push to get the front south of the
area. As storms move into the area, some of the storms could be
strong with good instability available and dry air in the low
levels, but wind shear is not strong nor are the lapse rates
aloft. Front may actually retreat back toward the north on Monday
as next upper shortwave trot moves into the northern plains,
before getting a push southward in the overnight hours Monday
night into early Tuesday. Have highs Monday near 90 in the south
to middle 80s north and will need to watch progression of the
front for sensible weather effects.
Synoptic pattern over the Central Plains remains zonal in nature,
with surface front near the area for much of the remainder of the
week with shortwave profs passing through the flow overhead.
Temperatures slowly fall Tuesday through Friday with rain chances
for much of the period given close proximity of the front. Upper
trot looks to deepen across the Great Lakes late in the week, and
usher in cooler high pressure behind.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z Sunday AFTERNOON)
ISSUED AT 1222 PM CDT SAT SEP 5 2015
VFR conditions will persist. Minor occasional gusts are likely in
the 16-23Z periods. LLWS may develop after 03Z but at this point
looks too uncertain to include.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Sanders
LONG TERM...67
AVIATION...65
AREA FORECAST DISCUSSION
NWS TOPEKA KS
609 AM CDT SAT SEP 5 2015
...Update to aviation forecast discussion...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 231 AM CDT SAT SEP 5 2015
Not much change to the overall pattern with southwest flow aloft
over the central and southern plains keeping the lee side trough in
place and a decent pressure gradient across eastern KS. Temperatures
will be a few degrees higher today so expect highs in the low to mid
90s with a few locations possibly reaching the upper 90s in central
KS. Southerly winds will again increase later today around 15 to 25
mph with gusts up to 35 mph. Later this morning a weak shortwave
will track over western NE and support showers and storms possibly
as far east as north central KS. The latest runs of the HRRR are now
hinting at isolated development in that area around sunrise, but
decided not to increase pops given the low uncertainty. The models
are showing mid level moisture spreading northward from the gulf
today coupled with cooler 850 mb temperatures across southeast KS.
This may lead to a weaker cap and an isolated shower or storm could
be possible south of I-35 this afternoon as daytime heating erodes
this cap. There is no obvious mid level support or any other focus
for lift so did not increase pops, but it could not be completely
ruled out. Tonight a cold front will drift eastward through the high
plains while several weak mid-level shortwaves track over the same
area. This should support storm development along the front in NE
during the overnight hours although have kept the northern forecast
area dry through sunrise.
.LONG TERM...(Sunday THROUGH Friday)
ISSUED AT 231 AM CDT SAT SEP 5 2015
Front still advancing across the Northern Plains on Sunday and
just starts to move into the far northwestern CWA by the late
afternoon hours. This leaves much of the area parked under the
thermal ridge for Sunday, with temperatures rising well into the
middle 90s. Heat indicies look to range from near 100 to 102F by
the afternoon hours. Northern counties may get some relief
overnight as front moves southward about halfway across the CWA,
but stalls out without a strong push to get the front south of the
area. As storms move into the area, some of the storms could be
strong with good instability available and dry air in the low
levels, but wind shear is not strong nor are the lapse rates
aloft. Front may actually retreat back toward the north on Monday
as next upper shortwave trot moves into the northern plains,
before getting a push southward in the overnight hours Monday
night into early Tuesday. Have highs Monday near 90 in the south
to middle 80s north and will need to watch progression of the
front for sensible weather effects.
Synoptic pattern over the Central Plains remains zonal in nature,
with surface front near the area for much of the remainder of the
week with shortwave profs passing through the flow overhead.
Temperatures slowly fall Tuesday through Friday with rain chances
for much of the period given close proximity of the front. Upper
trot looks to deepen across the Great Lakes late in the week, and
usher in cooler high pressure behind.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z Sunday MORNING)
ISSUED AT 608 AM CDT SAT SEP 5 2015
VFR conditions expected through the taf period.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Sanders
LONG TERM...67
AVIATION...Sanders
AREA FORECAST DISCUSSION
NWS TOPEKA KS
251 AM CDT SAT SEP 5 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 231 AM CDT SAT SEP 5 2015
Not much change to the overall pattern with southwest flow aloft
over the central and southern plains keeping the lee side trough in
place and a decent pressure gradient across eastern KS. Temperatures
will be a few degrees higher today so expect highs in the low to mid
90s with a few locations possibly reaching the upper 90s in central
KS. Southerly winds will again increase later today around 15 to 25
mph with gusts up to 35 mph. Later this morning a weak shortwave
will track over western NE and support showers and storms possibly
as far east as north central KS. The latest runs of the HRRR are now
hinting at isolated development in that area around sunrise, but
decided not to increase pops given the low uncertainty. The models
are showing mid level moisture spreading northward from the gulf
today coupled with cooler 850 mb temperatures across southeast KS.
This may lead to a weaker cap and an isolated shower or storm could
be possible south of I-35 this afternoon as daytime heating erodes
this cap. There is no obvious mid level support or any other focus
for lift so did not increase pops, but it could not be completely
ruled out. Tonight a cold front will drift eastward through the high
plains while several weak mid-level shortwaves track over the same
area. This should support storm development along the front in NE
during the overnight hours although have kept the northern forecast
area dry through sunrise.
.LONG TERM...(Sunday THROUGH Friday)
ISSUED AT 231 AM CDT SAT SEP 5 2015
Front still advancing across the Northern Plains on Sunday and
just starts to move into the far northwestern CWA by the late
afternoon hours. This leaves much of the area parked under the
thermal ridge for Sunday, with temperatures rising well into the
middle 90s. Heat indicies look to range from near 100 to 102F by
the afternoon hours. Northern counties may get some relief
overnight as front moves southward about halfway across the CWA,
but stalls out without a strong push to get the front south of the
area. As storms move into the area, some of the storms could be
strong with good instability available and dry air in the low
levels, but wind shear is not strong nor are the lapse rates
aloft. Front may actually retreat back toward the north on Monday
as next upper shortwave trof moves into the northern plains,
before getting a push southward in the overnight hours Monday
night into early Tuesday. Have highs Monday near 90 in the south
to middle 80s north and will need to watch progression of the
front for sensible weather effects.
Synoptic pattern over the Central Plains remains zonal in nature,
with surface front near the area for much of the remainder of the
week with shortwave trofs passing through the flow overhead.
Temperatures slowly fall Tuesday through Friday with rain chances
for much of the period given close proximity of the front. Upper
trof looks to deepen across the Great Lakes late in the week, and
usher in cooler high pressure behind.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z Saturday NIGHT)
ISSUED AT 1137 PM CDT FRI SEP 4 2015
VFR conditions are expected through the entire TAF period. Winds
will increase with gusts by mid to late morning, losing gusts
again by 23Z.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Sanders
LONG TERM...67
AVIATION...Barjenbruch
AREA FORECAST DISCUSSION
NWS JACKSON KY
1027 PM EDT SUN SEP 6 2015
.UPDATE...
ISSUED AT 1026 PM EDT SUN SEP 6 2015
FORECAST SEEMS TO BE WELL ON TRACK WITH CALM AND CLEAR CONDITIONS
POST SUNSET. MADE SOME MINOR ADJUSTMENTS TO THE NEAR TERM
FORECAST FOR TEMPS...WINDS...AND DEW POINTS TO MAKE SURE THEY ARE
WELL ON TRACK WITH THE CURRENT CONDITIONS. OTHERWISE...EXPECT A
QUIET NIGHT WITH THE EXCEPTION OF FOG DEVELOPMENT AFTER MIDNIGHT.
UPDATED GRIDS WERE SENT TO NDFD AND THE WEB AND A NEW ZONE
FORECAST PACKAGE HAS BEEN SENT OUT.
UPDATE ISSUED AT 550 PM EDT SUN SEP 6 2015
BASED ON THE EXTENT OF THE ISOLATED SHOWERS AND A FEW RUMBLES OF
THUNDER POPPING UP ACROSS THE CWA AND CENTRAL KY...WENT AHEAD AND
EXPANDED THE MENTION OF ISOLATED TSRA FOR THE NEXT COUPLE OF HOURS
ACROSS MUCH OF THE CWA. AT THIS POINT...THERE IS NOTHING VERY
IMPRESSIVE GOING ON...ALL SHOWERS ARE VERY SMALL AND PULSY IN
NATURE. AS WE LOSE SOME OF OUR DAYTIME HEATING IN THE NEXT COUPLE
OF HOURS...EXPECT THE SHOWERS AND ANY THUNDERSTORMS TO QUICKLY
DIMINISH THROUGH THE EVENING. UPDATED THE NEAR TERM GRIDS FOR
TEMPS...DEW POINTS...AND WINDS AS WELL TO BETTER REFLECT THE
CURRENT CONDITIONS AND WHAT IS EXPECTED THROUGH THIS EVENING AS
WELL. ALL GRIDS WERE SENT TO NDFD...HOWEVER...SINCE THE CURRENT
ZONE FORECAST STARTS WITH THE TONIGHT GROUP...DECIDED THERE IS NO
NEED FOR A FULL FORECAST PACKAGE UPDATE AT THIS TIME.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM EDT SUN SEP 6 2015
QUIET WEATHER IS IN STORE FOR THE RESIDENTS OF EASTERN KENTUCKY TO
BEGIN THE LABOR DAY HOLIDAY WORK WEEK. PARTLY CLOUDY SKIES ARE ON
TAP FOR THE REST OF THIS AFTERNOON WITH HOT AND HUMID CONDITIONS
IN PLACE AS WELL. A FEW RAIN SHOWERS POPPED UP EARLIER THIS
AFTERNOON ALONG THE TENNESSEE BORDER...BUT ONCE THOSE
DISSIPATED...NOTHING NEW HAS FORMED TO REPLACE THEM. IN FACT...IT
APPEARS THAT THE ATMOSPHERE...AT LEAST FOR NOW...HAS BECOME CAPPED
ACROSS EASTERN KENTUCKY. CENTRAL KENTUCKY...HOWEVER...HAS SEEN
QUITE A FEW SHOWERS AND STORMS FIRE UP OVER THE PAST HOUR OR SO
UNDER A LESS CAPPED ATMOSPHERE. IN GENERAL...THE FORECAST MODELS
ARE KEEPING EASTERN KENTUCKY FREE OF PRECIPITATION THROUGH TUESDAY
MORNING. THE ONLY MODEL THAT IS SHOWING ANY SORT OF CONVECTION
ACROSS OUR AREA TODAY IS THE HRRR WITH ITS SCATTERED SHOWERS AND
STORMS. THIS MODELS SOLUTION HAS NOT PANNED OUT THUS FAR...SO WILL
KEEP ONLY LOW POPS IN THE FORECAST FOR OUR AREA DOWN ALONG THE
TENNESSEE BORDER SINCE WE HAVE HAD SOME ACTIVITY DOWN THERE
ALREADY TODAY. ASIDE FROM THAT...IT APPEARS THAT THE ONLY OTHER
WEATHER ISSUE OF NOTE WILL BE THE FOG THAT ARE EXPECTING TO FORM
IN OUR VALLEYS AND NEAR BODIES OF WATER LATER TONIGHT.
TEMPERATURES WILL BE QUITE WARM THE REST OF TODAY AND
TOMORROW...WITH HIGHS STILL EXPECTED TO TOP OUT IN THE UPPER 80S
TO AROUND 90 EACH DAY. OVERNIGHT LOWS TONIGHT AND TOMORROW NIGHT WILL
BE TOLERABLE...WITH MIN READINGS IN THE LOW TO MID 60S EXPECTED
ACROSS THE AREA.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 405 PM EDT SUN SEP 6 2015
THE MODELS ARE IN GOOD AGREEMENT THROUGH THE END OF THE WORK
WEEK. THE UPPER LEVEL RIDGE THAT HAS BEEN DOMINATING THE MAJORITY
OF THE MISSISSIPPI VALLEY WILL BREAK DOWN...AS TROUGHING THAT HAD
BEEN RESTRICTED TO THE CONTINENTAL DIVIDE/NORTHERN
PLAINS...FINALLY PUSHES IN ACROSS THE OHIO VALLEY AND GREAT LAKES
REGIONS WEDNESDAY INTO THURSDAY. THE TROUGH LOOKS TO REACH ITS
PEAK AMPLITUDE BY FRIDAY...BEFORE GRADUALLY DAMPENING AND LIFTING
OUT TO THE NORTHEAST BY NEXT WEEKEND. THERE ARE SOME MODEL
DIFFERENCES THAT CREEP UP LATE IN THE PERIOD IN REGARDS TO
EVOLUTION OF THIS PATTERN...SO STUCK PRETTY CLOSE TO THE BLENDED
SOLUTION.
ONE MORE HOT DAY IS EXPECTED ON TUESDAY...WITH PERHAPS A FEW
STORMS DOWN ALONG THE TN/VA BORDER ONCE AGAIN. TEMPERATURES LOOK
TO REACH THE UPPER 80S TO AROUND 90 FOR MOST LOCATIONS. CLOUDS
WILL BE ON THE INCREASE LATE TUESDAY NIGHT INTO WEDNESDAY OUT
AHEAD OF THE APPROACHING TROUGH AND ITS ASSOCIATED SURFACE COLD
FRONT. GOOD CHANCE TO LIKELY POPS WILL BE IN THE OFFING WEDNESDAY
THROUGH THURSDAY...AS SEVERAL EMBEDDED SHORT WAVE TROUGHS AND THE
SLOW-MOVING SURFACE COLD FRONT MOVE THROUGH THE REGION.
BY FRIDAY...THE MAIN TROUGH AXIS AND SECONDARY COLD FRONT WILL
MOVE THROUGH THE AREA...BRINGING ONE MORE SHOT OF SHOWERS AND
THUNDERSTORMS. THE MODELS HAVE TRENDED A BIT MORE PROGRESSIVE IN
GENERAL...HOWEVER GIVEN THE HIGHER AMPLITUDE PATTERN...HAVE HELD
ONTO POPS A BIT LONGER THAN THE BLENDED GUIDANCE. A FEW SHOWERS
MAY LINGER IN THE SOUTHEAST INTO SATURDAY...AS ANOTHER TROUGH
SWINGS THROUGH THE OHIO VALLEY.
FOR TEMPERATURES...ABOVE NORMAL READINGS WILL TRANSITION TO NEAR
TO EVEN BELOW NORMAL THROUGH THE END OF THE PERIOD...AS DEW
POINTS EVENTUALLY RETURN TO THE 50S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 744 PM EDT SUN SEP 6 2015
DIURNAL CU AND ANY ASSOCIATED SHOWERS ARE QUICKLY DIMINISHING THIS
EVENING AS WE LOSE SUNLIGHT. MOSTLY CLEAR CONDITIONS SHOULD TAKE
HOLD FOR THE OVERNIGHT. AS HAS BEEN THE CASE FOR PREVIOUS
NIGHTS...WE WILL LIKELY SEE A GOOD FOG SET UP IN THE VALLEYS AS A
SUBSIDENCE INVERSION SETS IN AND WINDS GO CALM. THERE IS A
POSSIBILITY THAT THE FOG COULD LIFT AND MAKE IT INTO THE TAF
SITES WITH VARYING DEGREES OF VIS RESTRICTIONS DURING THE PRE DAWN
HOURS. GIVEN THAT THE CURRENT CONDITIONS ARE VERY MUCH LIKE THEY
WERE 24 HOURS AGO...BASED MUCH OF THE FOG POTENTIAL OFF OF WHAT
OCCURRED LAST NIGHT. FOG SHOULD BURN OFF AROUND 13Z
TOMORROW...WITH ANOTHER DAY OF FEW TO SCT DIURNAL VFR CLOUDS
EXPECTED. WINDS WILL CONTINUE TO BE LIGHT AND VARIABLE TOMORROW AS
WELL.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JMW
SHORT TERM...AR
LONG TERM...GEOGERIAN
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS JACKSON KY
744 PM EDT SUN SEP 6 2015
.UPDATE...
ISSUED AT 550 PM EDT SUN SEP 6 2015
BASED ON THE EXTENT OF THE ISOLATED SHOWERS AND A FEW RUMBLES OF
THUNDER POPPING UP ACROSS THE CWA AND CENTRAL KY...WENT AHEAD AND
EXPANDED THE MENTION OF ISOLATED TSRA FOR THE NEXT COUPLE OF HOURS
ACROSS MUCH OF THE CWA. AT THIS POINT...THERE IS NOTHING VERY
IMPRESSIVE GOING ON...ALL SHOWERS ARE VERY SMALL AND PULSY IN
NATURE. AS WE LOSE SOME OF OUR DAYTIME HEATING IN THE NEXT COUPLE
OF HOURS...EXPECT THE SHOWERS AND ANY THUNDERSTORMS TO QUICKLY
DIMINISH THROUGH THE EVENING. UPDATED THE NEAR TERM GRIDS FOR
TEMPS...DEW POINTS...AND WINDS AS WELL TO BETTER REFLECT THE
CURRENT CONDITIONS AND WHAT IS EXPECTED THROUGH THIS EVENING AS
WELL. ALL GRIDS WERE SENT TO NDFD...HOWEVER...SINCE THE CURRENT
ZONE FORECAST STARTS WITH THE TONIGHT GROUP...DECIDED THERE IS NO
NEED FOR A FULL FORECAST PACKAGE UPDATE AT THIS TIME.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM EDT SUN SEP 6 2015
QUIET WEATHER IS IN STORE FOR THE RESIDENTS OF EASTERN KENTUCKY TO
BEGIN THE LABOR DAY HOLIDAY WORK WEEK. PARTLY CLOUDY SKIES ARE ON
TAP FOR THE REST OF THIS AFTERNOON WITH HOT AND HUMID CONDITIONS
IN PLACE AS WELL. A FEW RAIN SHOWERS POPPED UP EARLIER THIS
AFTERNOON ALONG THE TENNESSEE BORDER...BUT ONCE THOSE
DISSIPATED...NOTHING NEW HAS FORMED TO REPLACE THEM. IN FACT...IT
APPEARS THAT THE ATMOSPHERE...AT LEAST FOR NOW...HAS BECOME CAPPED
ACROSS EASTERN KENTUCKY. CENTRAL KENTUCKY...HOWEVER...HAS SEEN
QUITE A FEW SHOWERS AND STORMS FIRE UP OVER THE PAST HOUR OR SO
UNDER A LESS CAPPED ATMOSPHERE. IN GENERAL...THE FORECAST MODELS
ARE KEEPING EASTERN KENTUCKY FREE OF PRECIPITATION THROUGH TUESDAY
MORNING. THE ONLY MODEL THAT IS SHOWING ANY SORT OF CONVECTION
ACROSS OUR AREA TODAY IS THE HRRR WITH ITS SCATTERED SHOWERS AND
STORMS. THIS MODELS SOLUTION HAS NOT PANNED OUT THUS FAR...SO WILL
KEEP ONLY LOW POPS IN THE FORECAST FOR OUR AREA DOWN ALONG THE
TENNESSEE BORDER SINCE WE HAVE HAD SOME ACTIVITY DOWN THERE
ALREADY TODAY. ASIDE FROM THAT...IT APPEARS THAT THE ONLY OTHER
WEATHER ISSUE OF NOTE WILL BE THE FOG THAT ARE EXPECTING TO FORM
IN OUR VALLEYS AND NEAR BODIES OF WATER LATER TONIGHT.
TEMPERATURES WILL BE QUITE WARM THE REST OF TODAY AND
TOMORROW...WITH HIGHS STILL EXPECTED TO TOP OUT IN THE UPPER 80S
TO AROUND 90 EACH DAY. OVERNIGHT LOWS TONIGHT AND TOMORROW NIGHT WILL
BE TOLERABLE...WITH MIN READINGS IN THE LOW TO MID 60S EXPECTED
ACROSS THE AREA.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 405 PM EDT SUN SEP 6 2015
THE MODELS ARE IN GOOD AGREEMENT THROUGH THE END OF THE WORK
WEEK. THE UPPER LEVEL RIDGE THAT HAS BEEN DOMINATING THE MAJORITY
OF THE MISSISSIPPI VALLEY WILL BREAK DOWN...AS TROUGHING THAT HAD
BEEN RESTRICTED TO THE CONTINENTAL DIVIDE/NORTHERN
PLAINS...FINALLY PUSHES IN ACROSS THE OHIO VALLEY AND GREAT LAKES
REGIONS WEDNESDAY INTO THURSDAY. THE TROUGH LOOKS TO REACH ITS
PEAK AMPLITUDE BY FRIDAY...BEFORE GRADUALLY DAMPENING AND LIFTING
OUT TO THE NORTHEAST BY NEXT WEEKEND. THERE ARE SOME MODEL
DIFFERENCES THAT CREEP UP LATE IN THE PERIOD IN REGARDS TO
EVOLUTION OF THIS PATTERN...SO STUCK PRETTY CLOSE TO THE BLENDED
SOLUTION.
ONE MORE HOT DAY IS EXPECTED ON TUESDAY...WITH PERHAPS A FEW
STORMS DOWN ALONG THE TN/VA BORDER ONCE AGAIN. TEMPERATURES LOOK
TO REACH THE UPPER 80S TO AROUND 90 FOR MOST LOCATIONS. CLOUDS
WILL BE ON THE INCREASE LATE TUESDAY NIGHT INTO WEDNESDAY OUT
AHEAD OF THE APPROACHING TROUGH AND ITS ASSOCIATED SURFACE COLD
FRONT. GOOD CHANCE TO LIKELY POPS WILL BE IN THE OFFING WEDNESDAY
THROUGH THURSDAY...AS SEVERAL EMBEDDED SHORT WAVE TROUGHS AND THE
SLOW-MOVING SURFACE COLD FRONT MOVE THROUGH THE REGION.
BY FRIDAY...THE MAIN TROUGH AXIS AND SECONDARY COLD FRONT WILL
MOVE THROUGH THE AREA...BRINGING ONE MORE SHOT OF SHOWERS AND
THUNDERSTORMS. THE MODELS HAVE TRENDED A BIT MORE PROGRESSIVE IN
GENERAL...HOWEVER GIVEN THE HIGHER AMPLITUDE PATTERN...HAVE HELD
ONTO POPS A BIT LONGER THAN THE BLENDED GUIDANCE. A FEW SHOWERS
MAY LINGER IN THE SOUTHEAST INTO SATURDAY...AS ANOTHER TROUGH
SWINGS THROUGH THE OHIO VALLEY.
FOR TEMPERATURES...ABOVE NORMAL READINGS WILL TRANSITION TO NEAR
TO EVEN BELOW NORMAL THROUGH THE END OF THE PERIOD...AS DEW
POINTS EVENTUALLY RETURN TO THE 50S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 744 PM EDT SUN SEP 6 2015
DIURNAL CU AND ANY ASSOCIATED SHOWERS ARE QUICKLY DIMINISHING THIS
EVENING AS WE LOSE SUNLIGHT. MOSTLY CLEAR CONDITIONS SHOULD TAKE
HOLD FOR THE OVERNIGHT. AS HAS BEEN THE CASE FOR PREVIOUS
NIGHTS...WE WILL LIKELY SEE A GOOD FOG SET UP IN THE VALLEYS AS A
SUBSIDENCE INVERSION SETS IN AND WINDS GO CALM. THERE IS A
POSSIBILITY THAT THE FOG COULD LIFT AND MAKE IT INTO THE TAF
SITES WITH VARYING DEGREES OF VIS RESTRICTIONS DURING THE PRE DAWN
HOURS. GIVEN THAT THE CURRENT CONDITIONS ARE VERY MUCH LIKE THEY
WERE 24 HOURS AGO...BASED MUCH OF THE FOG POTENTIAL OFF OF WHAT
OCCURRED LAST NIGHT. FOG SHOULD BURN OFF AROUND 13Z
TOMORROW...WITH ANOTHER DAY OF FEW TO SCT DIURNAL VFR CLOUDS
EXPECTED. WINDS WILL CONTINUE TO BE LIGHT AND VARIABLE TOMORROW AS
WELL.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JMW
SHORT TERM...AR
LONG TERM...GEOGERIAN
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
748 AM CDT SAT SEP 5 2015
...SOUNDING DISCUSSION...
AN UNSTABLE AND MOIST ATMOSPHERE WAS SAMPLED BY THE BALLOON THIS
MORNING WITH AN MLCAPE OVER 2000 J/KG AND A PRECIPITABLE WATER
THAT HAS PERSISTED ABOVE 2 INCHES FOR THE THE LAST 2 DAYS. MOST OF
THIS MOISTURE RICH AIR IS FOUND IN THE LOWER HALF OF THE
ATMOSPHERE WHERE WINDS ARE VARIABLE AND GENERALLY UNDER 10 KNOTS.
IN THE UPPER HALF OF THE ATMOSPHERE...THERE IS SOME DRIER AIR WITH
WINDS FROM THE NORTHWEST OR NORTH WITH A LAYER AVERAGE WIND SPEED
OF 25 TO 35 KNOTS. A CONVECTIVE TEMPERATURE OF 89 SHOULD BE
REACHED NEAR MIDDAY AND THE LATEST HRRR TRENDS TOWARD AN INCREASE
IN AREAL COVERAGE OF SHOWERS AND THUNDERSTORMS BETWEEN 17 AND 18Z.
12Z BALLOON INFO: THERE WERE NO ISSUES WITH THE FLIGHT THIS
MORNING THAT LASTED 101 MINUTES AND TRAVELED 28 MILES DOWNRANGE
FROM THE OFFICE. THE BALLOON ASCENDED TO A HEIGHT OF 19.3 MILES
ABOVE THE GROUND BURSTING OVER THE LOWER NINTH WARD.
ANSORGE
&&
.PREV DISCUSSION... /ISSUED 401 AM CDT SAT SEP 5 2015/
SHORT TERM...
ANOTHER DAY OF SUMMER WEATHER ACROSS THE FORECAST AREA...WITH
TEMPERATURES RISING BACK INTO THE LOWER TO MIDDLE 90S AND SOME
SCATTERED DIURNALLY INDUCED CONVECTION FROM LATE MORNING THROUGH
THE AFTERNOON HOURS. IT LOOKS LIKE CONVECTIVE CHANCES WILL BE
HIGHEST ALONG THE IMMEDIATE COAST OF LOUISIANA THIS MORNING...AND
THEN THE RISK OF CONVECTION WILL TRANSITION MORE INLAND AS THE DAY
PROCEEDS. IT LOOKS LIKE SOME HIGHER THETA E VALUES AND INCREASED
MOISTURE POOLING DUE TO A CONVERGENT WIND FIELD WILL BE FOUND
OVER THE FAR WESTERN PART OF THE CWA...CLOSER TO THE ATCHAFALAYA
BASIN...AND WOULD EXPECT TO SEE SOMEWHAT HIGHER CONVECTIVE CHANCES
IN THAT REGION. RAIN CHANCES COULD INCREASE TO AROUND 30-40
PERCENT OVER THE FAR WESTERN PARISHES...WITH 20 TO 30 PERCENT RAIN
CHANCES FOR THE REMAINDER OF THE AREA TODAY. ANY CONVECTION WILL
BE TROPICAL IN NATURE...WITH A QUICK HIT OF HEAVY RAINFALL FOR
SEVERAL MINUTES AND THEN A RETURN TO THE HOT AND STEAMY
CONDITIONS THAT PRECEDED THE SHOWER OR STORM.
A SLOWLY RETROGRADING UPPER LEVEL LOW WILL SHIFT FROM THE
SOUTHEASTERN CONUS INTO THE EASTERN GULF OF MEXICO SUNDAY THROUGH
TUESDAY. INITIALLY...THE REGION WILL REMAIN ON THE DRIER AND MORE
STABLE SIDE OF THE UPPER LEVEL LOW...AND EXPECT TO SEE CONTINUED
SUMMER LIKE WEATHER ACROSS THE AREA WITH SCATTERED AFTERNOON
CONVECTION AND HIGHS RISING INTO THE LOWER TO MIDDLE 90S ACROSS
THE AREA THROUGH MONDAY. HOWEVER...ON TUESDAY...THE UPPER LEVEL
LOW WILL BECOME MORE CENTERED OVER THE FORECAST AREA. WITH THE LOW
DIRECTLY OVER THE AREA...STRONGER FORCING WILL TAKE HOLD
ALOFT...AND A PLUME OF DEEPER TROPICAL MOISTURE WILL STREAM INTO
THE REGION ON THE BACK OF DEEPENING SOUTHEASTERLY FLOW. AS A
RESULT...EXPECT TO SEE HIGHER CHANCES OF RAIN ALONG THE COAST AND
HAVE POPS BOOSTED UP TO 40 PERCENT. CLOUD COVER WILL ALSO BE ON
THE INCREASE...AND EXPECT TO SEE DAYTIME HIGHS FALL BACK INTO THE
UPPER 80S AND LOWER 90S BY TUESDAY.
LONG TERM...
BOTH THE EURO AND GFS INDICATE THAT THE RETROGRADING TROUGH WILL
BEGIN TO WEAKEN ON WEDNESDAY...AS A DEEPENING NORTHERN STREAM
TROUGH BEGINS TO INFLUENCE THE REGION. THERE WILL STILL BE AMPLE
FORCING AND LIFT OVER THE REGION AS THE COMBINATION OF THE
WEAKENING SYSTEM AND INCREASING POSITIVE VORTICITY ADVECTION FROM
THE APPROACHING NORTHERN STREAM TROUGH WORK IN CONJUNCTION. AS A
RESULT...KEEP CHANCE POPS IN PLACE DURING PEAK HEATING HOURS ON
WEDNESDAY.
BY THURSDAY...THE SOUTHERN STREAM TROUGH WILL HAVE BECOME FULLY
INTEGRATED INTO THE MUCH STRONGER NORTHERN STREAM TROUGH AS IT
CONTINUES TO DIG INTO THE LOWER MISSISSIPPI VALLEY. AS THIS TROUGH
DEEPENS...A FAIRLY STRONG COLD FRONT WILL FORM OVER THE SOUTHERN
PLAINS AND BEGIN TO APPROACH THE GULF COAST. HOWEVER...THE
FORECAST AREA SHOULD BE JUST FAR ENOUGH SOUTH TO AVOID IMPACTS
FROM THIS FRONT ON THURSDAY. AS A RESULT...ONLY EXPECT TO SEE THE
SAME PATTERN OF SCATTERED MAINLY AFTERNOON CONVECTION ON THURSDAY.
THE FRONT WILL BEGIN TO INFLUENCE THE REGION MORE DIRECTLY
THURSDAY NIGHT AND ESPECIALLY ON FRIDAY AND SATURDAY AS A SLOW FRONTAL
PASSAGE OCCURS. EXPECT TO SEE SEVERAL WAVES OF SHOWERS AND
THUNDERSTORMS MOVE ACROSS THE AREA AS A SERIES OF WEAK UPPER
LEVEL IMPULSES RIDING ON THE BACK OF A JET STREAK ALOFT SLIDE
ACROSS THE GULF SOUTH. THE SURFACE FRONT WILL SERVE AS A LOW LEVEL
FOCUS FOR CONVECTION TO INITIATE AS THESE IMPULSES ALOFT MOVE
THROUGH. GIVEN THESE CONDITIONS...HAVE HIGH END CHANCE POPS IN
PLACE FOR THE END OF THE WEEK. HIGHS WILL BE MUCH COOLER DUE TO
THE EXPECTED RAINFALL AND CLOUD COVER...WITH TEMPERATURES ONLY
RISING INTO THE MIDDLE TO UPPER 80S.
AVIATION...
NOT AS MUCH TS COVERAGE EXPECTED TODAY. WILL SHOW VCTS FOR BTR AND
HDC SINCE THOSE TWO TERMINALS SHOULD HAVE THE BEST CHANCES OF
RECEIVING ANY ACTIVITY. VFR CONDITIONS WILL BE THE NORM THROUGH THE
TAF PERIOD FOR MOST SITES. WILL SHOW SOME VIS RESTRICTIONS FOR
BTR...HDC AND HUM SINCE THEY MAY GET RAIN TODAY. IF NO RAIN...THEN
VIS WILL ONLY HAVE MINOR MVFR RESTRICTIONS. &&
MARINE...
PRESSURE GRADIENT IS RELAXED ACROSS THE GULF...FAIRLY NORMAL FOR THE
LATE SUMMER DOLDRUMS. DEEP TROPICAL MOISTURE AND AN UPPER TROUGH WILL
REMAIN OVER THE GULF. THIS WEAKNESS WILL KEEP HIGHER CHANCES OF TS
ACTIVITY IN THE COASTAL WATERS THROUGH MUCH OF THE FORECAST. WINDS
AND SEAS WILL BE HIGHER NEAR SCATTERED TS. WIND GUSTS COULD BE AS
HIGH AS 30 KNOTS WITH THE STRONGEST ACTIVITY. OUTSIDE TS
ACTIVITY...CONDITIONS WILL REMAIN RATHER BENIGN WITH A WEAK
PRESSURE GRADIENT. NOCTURNAL ACTIVITY WILL BE THE MOST ABUNDANT
WHILE THERE WILL BE A GENERAL DECREASE IN ACTIVITY DURING THE
LATE MORNING THROUGH LATE AFTERNOON HOURS.
DECISION SUPPORT...
DSS CODE....GREEN.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...NONE.
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED WATCH/WARNING/ADVISORY
ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE RISK SVR AND/OR DIRECT
TROPICAL THREATS; EVENTS OF NATIONAL SIGNIFICANCE
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 96 72 95 70 / 30 30 20 20
BTR 92 73 95 73 / 30 20 20 20
ASD 92 75 92 73 / 30 30 20 20
MSY 91 77 92 76 / 30 20 30 20
GPT 91 76 90 74 / 30 20 30 20
PQL 91 74 91 73 / 30 20 30 20
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
813 PM EDT SUN SEP 6 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 327 PM EDT SUN SEP 6 2015
A SHORTWAVE THAT MOVED THROUGH LAST NIGHT INTO THIS MORNING PRODUCED
HEAVY RAIN OVER WRN LAKE SUPERIOR AND MN...AND EVEN BROUGHT SHOWERS
AND THUNDERSTORMS TO FAR WRN UPPER MI AND ERN LAKE SUPERIOR. OVER
MOST LAND AREAS...AN EML WAS TOO STRONG TO ALLOW CONVECTION TO
CONDITIONS...WITH ONLY A FEW DROPS HAVING FALLEN AT WFO MQT TODAY AS
A ROGUE SHOWER PASSED BY. CLOUD COVER HAS BEEN MORE EXTENSIVE DUE TO
THE MORNING CONVECTION...AS WELL AS CONVECTION UPSTREAM OVER WI THAT
HAS SENT HIGH CLOUDS OVER MUCH OF THE AREA. THIS HAS BROUGHT DOWN
MAX TEMPS A FEW DEGREES FROM WHAT WAS PREVIOUSLY EXPECTED.
STILL...MUGGY CONDITIONS PERSIST AS LOW-MID 80S TEMPS AND LOW 70S
DEW POINTS ARE BEING OBSERVED.
MODELS HAVE NOT PERFORMED WELL ALL DAY...EVEN THE HRRR HAS CONTINUED
TO INITIALIZE WITH HEAVY PRECIP OVER WRN UPPER MI WHERE NON EXISTS.
THIS SEEMS LIKELY DUE TO AN UNDERESTIMATION OF BOTH THE STRENGTH OF
THE EML/CIN AND POOR HANDLING OF MORNING PRECIP/CLOUD COVER. LATEST
RUNS OVER MANY HIGH-RES MODELS ARE NOW DOING A DECENT JOB WITH QPF
OVER THE CWA AT THE PRESENT...BUT ARE VERY POOR IN THEIR HANDLING OF
UPSTREAM CONVECTION OVER NERN MN (ASSOCIATED WITH A COLD FRONT
MOVING SE) AND CONVECTION OVER WRN WI AND SOUTH MN AHEAD OF A
SHORTWAVE AND WEAK SFC LOW NEAR THE MN/SD BORDER. THE HRRR IS
HANDLING UPSTREAM CONVECTION WELL...AND IT ALSO IS SIMILAR TO THE
OTHER MODELS BY TIME THE NEXT ROUND OF CONVECTION MOVES IN MAINLY
AFTER 00Z THIS EVENING. THIS LENDS GREATER CONFIDENCE TO OTHER
MODELS...SO WILL USE THEN SINCE THEY ALSO ARE DOING WELL NOW. MAIN
MODELS USED ARE THE NAM...NAM DNG...REGIONAL GEM...NCEP HIGH-RES WRF
ARW AND NMM. SHOWERS AND THUNDERSTORMS WILL MOVE IN AFTER 00Z THIS
EVENING AS THE SHORTWAVE EJECTS INTO THE AREA AND THE SFC LOW MOVES
THROUGH THE N...DRIVING THE COLD FRONT THROUGH. HEAVY RAIN IS
EXPECTED IN ANY THUNDERSTORMS DUE TO WELL ABOVE NORMAL
MOISTURE/PWATS. OTHER THREATS ARE POSSIBLY LARGE HAIL AND DAMAGING
WINDS...MAINLY OVER THE W. MUCAPES OF 1000-1500J/KG (MAINLY THIS
HIGH OVER THE W) AND 0-6KM BULK SHEAR AROUND 30 ARE MARGINAL
VALUES...SO SOME STRONG TO SEVERE STORMS ARE POSSIBLE OVER THE
W...BUT NOT LIKELY.
STILL SOME UNCERTAINTY MON. MODELS GENERALLY AGREE THAT MOST OF THE
PRECIP WILL BE E OF THE CWA BY 18Z...EXCEPT MAYBE A COUPLE NUISANCE
SHOWERS OVER THE E. HOWEVER...THE NAM AND NCEP HIGH-RES WRF NMM ARE
SHOWING CONVECTION BREAKING OUT IN THE AFTERNOON OVER ERN UPPER MI.
HOWEVER...DID NOT INCORPORATE THAT INTO THE FORECAST AT THIS TIME AS
THOSE MODELS SEEM TO BE OVERDOING SFC TEMPS AND INSTABILITY. SKIES
SHOULD CLEARING FROM THE W...LAGGING THE LONGEST OVER THE E NEAR
LAKE SUPERIOR. HIGHS SHOULD BE IN THE 70S TO AROUND 80...WARMEST FAR
SOUTH CENTRAL.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 449 PM EDT SUN SEP 6 2015
MONDAY NIGHT THROUGH TUESDAY...THE GFS AND ECMWF WERE IN RELATIVELY
GOOD AGREEMENT WITH THE STRENGTH/POSITION OF THE SHORTWAVE MOVING
OUT OF THE PLAINS TOWARD THE GREAT LAKES THAT SUPPORTS DEVELOPMENT
OF A SFC WAVE ALONG THE FRONT. WITH MOST OF THE PCPN TO THE SOUTH OF
THE CWA...CHANCE POPS WERE MAINTAINED FOR THE SE HALF...ESPECIALLY
ALONG LAKE MICHIGAN.
TUE NIGHT INTO WED...HIGH PRES WILL BUILD INTO THE WRN LAKES TUE
NIGHT INTO WED WITH CLEARING SKIES. LOOK FOR TEMPS NEAR SEASONAL
AVERAGES WITH LOWS AROUND 50 TO 55 AND HIGHS AROUND 70.
THU-FRI...THE GFS/GEFS/ECMWF REMAIN IN RELATIVELY GOOD AGREEMENT
WITH THE SHORTWAVE TROUGH DIGGING TOWARD THE UPPER MS VALLEY WED
NIGHT AND THROUGH THE NRN LAKES THU. ELEVATED INSTABILITY MAY BE
MARGINAL FOR TSRA...BUT WITH MODERATE TO STRONG DEEP LAYER QVECTOR
CONV AND FAVORABLE MOISTURE TRANSPORT...AT LEAST ISOLD TS WILL BE
POSSIBLE. THE 12Z ECMWF HAS TRENDED BACK TOWARD A DEEPER TROUGH INTO
THE GREAT LAKES BY FRI WITH DEEP MOISTURE AND NRLY CYCLONIC FLOW
THAT WOULD SUPPORT SHOWERS AND LAKE ENHANCED RAIN INTO UPPER MI.
EVEN THOUGH GFS IS MORE PROGRESSIVE AND NOT AS DEEP WITH THE
TROUGH...850 MB TEMPS TO AROUND 2C (LAKE TEMPS AROUND 15C) MAY STILL
BE COLD ENOUGH TO PRODUCE SOME LAKE EFFECT PCPN. MORE FALL-LIKE
CONDITIONS ARE EXPECTED WITH HIGHS ONLY IN THE UPPER 50S AND LOWER
60S FRI.
SAT-SUN...ALTHOUGH A TRANSITION BACK TOWARD A MORE ZONAL PATTERN IS
EXPECTED WITH MODERATING TEMPS SAT...THERE IS UNCERTAINTY WITH THE
AMOUNT OF HEIGHT FALLS INTO THE NRN CONUS ASSOCIATED WITH A
SHORTWAVE MOVING TOWARD HUDSON BAY OR NW ONTARIO. THE 12Z/6
ECMWF...UNLIKE THE DRY GFS AND 00Z/6 ECMWF DROPS A SHORTWAVE AND
FRONT WITH PCPN INTO THE NRN LAKES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 812 PM EDT SUN SEP 6 2015
APPROACHING COLD FRONT AND AN UNSEASONABLY WARM/HUMID AIR MASS WILL
RESULT IN SHRA/TSRA...SOME WITH VERY HVY RAIN...AFFECTING
KIWD/KCMX/KSAW THIS EVENING. SHRA/TSRA THAT PASS OVER THE TERMINALS
WILL PRODUCE A BRIEF PERIOD OF MVFR OR EVEN IFR CONDITIONS. LATER
TONIGHT...IFR/LIFR CONDITIONS WILL DEVELOP AT ALL TERMINALS. LIFR
MORE LIKELY AT KCMX WITH FAVORABLE UPSLOPING AND ALSO AT KSAW WHERE
COLD FRONT WON`T PASS UNTIL MID MORNING. IMPROVEMENT TO VFR WILL
OCCUR FROM W TO E AT ALL TERMINALS FROM LATE MORNING THRU MID AFTN
ON MON AS DRIER AIR ARRIVES BEHIND COLD FRONT.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 327 PM EDT SUN SEP 6 2015
FOG WILL REMAIN A CONCERN UNTIL THE FRONTAL PASSAGE LATE TONIGHT AS
HIGH DEW POINTS KEEP MOVING ACROSS THE COLDER WATER. SOUTH WINDS
TODAY WILL TURN WESTERLY ON MONDAY THEN DECREASE MON NIGHT INTO TUE.
OVERALL...NEXT WEEK LOOKS FAIRLY QUIET ON THE LAKE WITH NO MAJOR
SYSTEMS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...TITUS
LONG TERM...JLB
AVIATION...ROLFSON
MARINE...TITUS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
158 PM EDT SAT SEP 5 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 308 AM EDT SAT SEP 5 2015
A WARM FRONT WILL LIFT NORTHWARD THROUGH THE REGION TODAY LEADING
TO SOME SHOWERS AND THUNDERSTORMS. HIGH PRESSURE CONTROLS OUR
WEATHER ON SUNDAY WHICH SHOULD END UP A MOSTLY DRY AND VERY WARM
DAY. THE CHANCES FOR SHOWERS AND THUNDERSTORMS WILL INCREASE AS WE
GO THROUGH LABOR DAY AND INTO TUESDAY AS A SLOW MOVING COLD FRONT
NEARS FROM THE WEST. THE TEMPERATURES WILL STILL END UP WELL ABOVE
NORMAL EARLY NEXT WEEK.
&&
.UPDATE...
ISSUED AT 1039 AM EDT SAT SEP 5 2015
WE HAVE UPDATED TO FCST THIS MORNING TO EXTEND THE DENSE FOG
ADVISORY UNTIL NOON UP NORTH. WE HAVE ALSO INCREASED THE
SHOWER/STORM CHCS DOWN SOUTH WITH PLENTY OF COVERAGE ALREADY IN
PLACE DOWN THERE.
THE FOG UP NORTH HAS BEEN SLOW TO DISSIPATE THIS MORNING WITH MANY
LOCATIONS STILL AT 1/4SM OR LESS LEADING UP TO THE INITIAL
EXPIRATION TIME OF 10 AM THIS MORNING. WITH A LACK OF WIND TO MIX
THINGS UP AND PLENTY OF STRATUS IN PLACE...IT WILL TAKE A LITTLE
LONGER THAN PREVIOUSLY EXPECTED TO MIX IT OUT. WE GAVE IT UNTIL
NOON FOR MORE OF A BUFFER. WE WILL CANCEL IT EARLY IF ALL SITES
COME UP SOONER.
PLENTY OF SHOWERS AND STORMS ACROSS THE SOUTH THIS MORNING. THE
PESKY WEAK UPPER LOW THAT HAS BEEN MEANDERING ACROSS THE STATE THE
PAST COUPLE OF DAYS IS OVER LAKE MICHIGAN EARLY THIS MORNING. IT
NOW LOOKS LIKE IT IS MAKING A MOVE TO THE EAST...AND FIRING PLENTY
OF SHOWERS/STORMS AHEAD OF IT WITH THE MOIST AIR MASS IN PLACE.
IT APPEARS THIS WILL CONTINUE EAST THROUGH THE DAY AND PUSH THE
MORE WIDESPREAD COVERAGE EAST BY LATER THIS AFTERNOON. WE CAN NOT
RULE OUT A POP UP SHOWER/STORM WITH THE UPPER LOW STILL NEARBY.
WEAK SHEAR AND LIMITED INSTABILITY WILL KEEP THINGS GENERALLY
TAME. HEAVY DOWNPOURS WOULD BE THE GREATEST THREAT WITH THE SLOW
MOVEMENT.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 308 AM EDT SAT SEP 5 2015
DENSE FOG HAS BEEN INCREASING OVER THE PAST FEW HOURS AND NOW
COVERS MUCH OF THE REGION. HRRR RUC SUGGESTS THE FOG WILL PERSIST
THROUGH DAYBREAK. WILL GO WITH AN ADVISORY AND CARRY IT UNTIL MID
MORNING. WE MAY SEE GRADUAL IMPROVEMENT IN THE VISIBILITIES FROM
SOUTH TO NORTH BEFORE DAYBREAK AS THE ELEVATED WARM FRONT MOVES
IN.
THE ATMOSPHERE WILL BE UNSTABLE THROUGH THE DAY. SOME LIFT ARRIVES
WITH THE ELEVATED WARM FRONT MOVING IN THIS MORNING FROM THE
SOUTH. THEREFORE WILL KEEP THE MENTION OF SHOWERS AND
THUNDERSTORMS IN THE FORECAST. LITTLE OR NO FORCING IS AROUND
TONIGHT INTO SUNDAY. WILL KEEP IT DRY FOR NOW. THE ATMOSPHERE
BECOMES RATHER UNSTABLE ON SUNDAY...SO WILL NEED TO MONITOR THIS
CLOSELY. SUNDAY SHOULD BE ONE OF THE WARMEST DAYS OF THE SEASON AS
THE LOW LEVEL THERMAL RIDGE ADVECTS IN FROM THE SOUTHWEST.
WILL FEATURE AN INCREASING RISK FOR SHOWERS AND THUNDERSTORMS ON
LABOR DAY. MODELS VARY ON THE TIMING OF ANY PRECIPITATION. HOWEVER
GIVEN THE APPROACHING FRONT DURING THE AFTERNOON WILL ENCOUNTER AN
UNSTABLE AIRMASS...IS SEEMS THAT A RISK FOR THUNDERSTORMS WILL
EXIST. WILL HIGHLIGHT THE AFTERNOON FOR POSSIBLE THUNDERSTORMS.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 308 AM EDT SAT SEP 5 2015
MAIN FOCUS IS CURRENTLY ON THE THREAT FOR HEAVY RAINFALL MONDAY
NIGHT THROUGH TUESDAY NIGHT WITH SOME TRAINING THUNDERSTORMS
POSSIBLE IN ASSOCIATION WITH MAINLY UNIDIRECTIONAL WINDS IN THE
PROFILE...A VERY MOIST AIRMASS...AND A WARM FRONT LIFTING THROUGH
DURING THIS PERIOD. MANY AREAS NEAR AND NORTH OF I-96 ARE EXPECTED
TO RECEIVE ONE TO TWO INCHES OF RAIN BY WEDNESDAY MORNING WITH
HIGHER AMOUNTS QUITE POSSIBLE.
I BELIEVE THERE ARE SOME KEY INGREDIENTS COMING IN PLACE FOR LOCALLY
EXCESSIVE RAINFALL ACROSS WEST CENTRAL AND SOUTHWEST LOWER MI. AS
HAS BEEN MENTIONED MANY TIMES...A WEAK COLD FRONT WILL WASH OUT
ACROSS THE CWA MONDAY...WHICH WILL BECOME STATIONARY AND THEN LIFT
NORTH AS A WARM FRONT TUESDAY. JUST HOW FAR NORTH THIS BOUNDARY
LIFTS IS QUESTIONABLE GIVEN NUMEROUS AREAS OF CONVECTION THAT COULD
SUPPRESS THE FRONT SOUTHWARD. CURRENTLY FAVORING THE ECMWF WITH THIS
SYSTEM GIVEN A FEW DIFFERENT GYRATIONS NOTED WITH THE GFS RECENTLY
WITH HOW QUICK THE BOUNDARY WILL MOVE THROUGH.
DEEP LAYER RH (H1000-H500) ON TUESDAY COULD TOP 90% FOR A GOOD
PORTION OF THE CWA...ESPECIALLY FROM GRR TO THE NORTH. ALL OF THE
MODELS ARE ALSO SHOWING SOME H1000-H700 WIND CONVERGENCE. A 20 KT
LLJ AT 00Z TUES STRENGTHENS TO 30-35 KT BY 00Z WED. HIGHER UP...WE
WILL BE SQUARELY IN THE RIGHT ENTRANCE REGION OF A 100 KT JET STREAK
AS H500 POSITIVE VORTICITY ADVECTION MOVES INTO THE CWA DURING THE
MORNING AND AFTERNOON HOURS. NEAR THE SURFACE...THE WARM FRONT WILL
BE DRAPED ACROSS THE CWA NEAR GRR AT 12Z TUESDAY...POSSIBLY LIFTING
NORTH TOWARD ROUTE 10 BY 18Z. DEW POINT READINGS AROUND 70 COUPLED
WITH PW VALUES OF 2.00-2.25" STRONGLY SUGGEST ANY STORMS WOULD BE
CAPABLE OF HEAVY DOWNPOURS. IF THE NWP SOLUTIONS CONTINUE SUPPORTING
THESE DETAILS...COULD FORESEE A FLOOD THREAT FOR AREAS THAT GET THE
MOST PERSISTENT RAINS.
IN TERMS OF ANY SEVERE WEATHER THREAT...IT IS UNCLEAR AT THIS TIME.
ONGOING CONVECTION EARLY TUESDAY COULD HAMPER ANY DESTABILIZATION
DURING THE AFTERNOON. SFC BASED CAPE IS NOT MUCH MORE THAN 1000 J/KG
FOR THE AREA ON TUESDAY...THOUGH BULK SHEAR IS LOOKING MUCH BETTER
OFF THE ECMWF AT AROUND 35-40 KTS. IT IS ALSO SHOWING 100-150 M2/S2
OF 0-1 KM HELICITY COURTESY OF THE WARM FRONT NEARBY. NOT OUT OF THE
QUESTION THERE COULD BE SOME STRONGER STORMS CAPABLE OF GUSTY WINDS
AND SOME HAIL IF WE CAN DESTABILIZE SUFFICIENTLY.
BEYOND THIS PERIOD...LOOKING AT A PATTERN CHANGE FOR THE SECOND HALF
OF THE WEEK AND THE WEEKEND IN PARTICULAR. TROPICAL STORM IGNACIO
WILL GET SWEPT UP IN MID LEVEL FLOW OVER THE GULF OF ALASKA.
FOLLOWING THE ECMWF H500 HEIGHT FIELD...THIS HELPS DIG A TROUGH INTO
THE GREAT LAKES FOR FRIDAY AND SATURDAY...WITH CHILLY TEMPS AND
SCATTERED SHOWERS EXPECTED BY SATURDAY WITH HIGHS STRUGGLING INTO
THE 60S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 157 PM EDT SAT SEP 5 2015
VFR CONDITIONS WILL PREVAIL THROUGH THE AFTERNOON WITH ONLY A FEW
ISOLATED AREAS OF IFR WITH SHOWERS AND THUNDERSTORMS. AREAS OF IFR
IN FOG IS EXPECTED ONCE AGAIN TONIGHT. WINDS WILL BE FROM THE SOUTH
OR SOUTHWEST AOB 10 KNOTS.
&&
.MARINE...
ISSUED AT 308 AM EDT SAT SEP 5 2015
WINDS AND WAVES INCREASE SUNDAY INTO SUNDAY NIGHT AS THE WARM AIR
ADVECTION STRENGTHS AHEAD OF THE APPROACHING COLD FRONT. WILL NEED
TO MONITOR LITTLE AND BIG SABLE POINTS FOR A POSSIBLE SMALL CRAFT
ADVISORY AND ASSOCIATED BEACH HAZARDS. RIGHT NOW I HAVE WAVES
INCREASING TO 2 TO 4 FEET.
&&
.HYDROLOGY...
ISSUED AT 1214 AM EDT SAT SEP 5 2015
LOCALIZED HEAVY RAINFALL HAS FALLEN OVER SOUTHERN PORTIONS OF THE
FORECAST AREA THIS MORNING. RADAR ESTIMATES SHOW MOST OF THE
RAINFALL ALONG AND SOUTH OF I-96 WITH SPOTTY ESTIMATES POSSIBLY
EXCEEDING ONE INCH. THOUGH THIS IS NOT AN IMMEDIATE PLAYER IN ANY
RIVER FLOODING IT COULD PLAY A ROLE IN NEXT WEEKS RAINFALL
POTENTIAL.
A BRIEF DRY PERIOD LATE TONIGHT THROUGH THE EARLY HALF OF MONDAY
WILL HELP IN ALLOWING RUNOFF TO MAKE ITS WAY DOWN STREAMS AND
RIVERS. THIS MAY BE BENEFICIAL IN THE EVENT THAT THE LATE MONDAY
THROUGH WEDNESDAY TIMEFRAME BRINGS HEAVY RAIN. THOUGH QUESTIONS
STILL EXIST IN PLACEMENT...IT IS BECOMING MORE EVIDENT THAT
MOISTURE FLOWS IN THIS DIRECTION AS PWATS APPROACH 2.0 INCHES.
THIS COUPLED WITH THE SLOW MOVEMENT OF THE FRONTAL BOUNDARY MAY
AID IN ROUNDS OF HEAVY RAINFALL ALONG THE BOUNDARY THROUGH
PORTIONS OF THE FORECAST AREA. WHILE EVERYONE HAS THE THE
POTENTIAL TO SEE SOME DECENT RAINFALL...SOME LOCATIONS MAY EASILY
ACCUMULATE AN INCH OR MORE IN OR AROUND THUNDERSTORMS. ANY
PREVIOUS RAINFALL FROM TODAY COULD HAVE DEPOSITED ENOUGH MOISTURE
TO SOUTHERN SECTIONS... ALLOCATING ADDITIONAL RAINFALL MORE SO TO
RUNOFF THAN TO GROUND WATER. SO THE PLACEMENT OF THE HEAVY RAIN
NEXT WEEK IS SOMETHING TO WATCH.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...NJJ
SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...HOVING
AVIATION...OSTUNO
HYDROLOGY...JAM
MARINE...MJS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1214 PM EDT SAT SEP 5 2015
LATEST UPDATE...
HYDRO
.SYNOPSIS...
ISSUED AT 308 AM EDT SAT SEP 5 2015
A WARM FRONT WILL LIFT NORTHWARD THROUGH THE REGION TODAY LEADING
TO SOME SHOWERS AND THUNDERSTORMS. HIGH PRESSURE CONTROLS OUR
WEATHER ON SUNDAY WHICH SHOULD END UP A MOSTLY DRY AND VERY WARM
DAY. THE CHANCES FOR SHOWERS AND THUNDERSTORMS WILL INCREASE AS WE
GO THROUGH LABOR DAY AND INTO TUESDAY AS A SLOW MOVING COLD FRONT
NEARS FROM THE WEST. THE TEMPERATURES WILL STILL END UP WELL ABOVE
NORMAL EARLY NEXT WEEK.
&&
.UPDATE...
ISSUED AT 1039 AM EDT SAT SEP 5 2015
WE HAVE UPDATED TO FCST THIS MORNING TO EXTEND THE DENSE FOG
ADVISORY UNTIL NOON UP NORTH. WE HAVE ALSO INCREASED THE
SHOWER/STORM CHCS DOWN SOUTH WITH PLENTY OF COVERAGE ALREADY IN
PLACE DOWN THERE.
THE FOG UP NORTH HAS BEEN SLOW TO DISSIPATE THIS MORNING WITH MANY
LOCATIONS STILL AT 1/4SM OR LESS LEADING UP TO THE INITIAL
EXPIRATION TIME OF 10 AM THIS MORNING. WITH A LACK OF WIND TO MIX
THINGS UP AND PLENTY OF STRATUS IN PLACE...IT WILL TAKE A LITTLE
LONGER THAN PREVIOUSLY EXPECTED TO MIX IT OUT. WE GAVE IT UNTIL
NOON FOR MORE OF A BUFFER. WE WILL CANCEL IT EARLY IF ALL SITES
COME UP SOONER.
PLENTY OF SHOWERS AND STORMS ACROSS THE SOUTH THIS MORNING. THE
PESKY WEAK UPPER LOW THAT HAS BEEN MEANDERING ACROSS THE STATE THE
PAST COUPLE OF DAYS IS OVER LAKE MICHIGAN EARLY THIS MORNING. IT
NOW LOOKS LIKE IT IS MAKING A MOVE TO THE EAST...AND FIRING PLENTY
OF SHOWERS/STORMS AHEAD OF IT WITH THE MOIST AIR MASS IN PLACE.
IT APPEARS THIS WILL CONTINUE EAST THROUGH THE DAY AND PUSH THE
MORE WIDESPREAD COVERAGE EAST BY LATER THIS AFTERNOON. WE CAN NOT
RULE OUT A POP UP SHOWER/STORM WITH THE UPPER LOW STILL NEARBY.
WEAK SHEAR AND LIMITED INSTABILITY WILL KEEP THINGS GENERALLY
TAME. HEAVY DOWNPOURS WOULD BE THE GREATEST THREAT WITH THE SLOW
MOVEMENT.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 308 AM EDT SAT SEP 5 2015
DENSE FOG HAS BEEN INCREASING OVER THE PAST FEW HOURS AND NOW
COVERS MUCH OF THE REGION. HRRR RUC SUGGESTS THE FOG WILL PERSIST
THROUGH DAYBREAK. WILL GO WITH AN ADVISORY AND CARRY IT UNTIL MID
MORNING. WE MAY SEE GRADUAL IMPROVEMENT IN THE VISIBILITIES FROM
SOUTH TO NORTH BEFORE DAYBREAK AS THE ELEVATED WARM FRONT MOVES
IN.
THE ATMOSPHERE WILL BE UNSTABLE THROUGH THE DAY. SOME LIFT ARRIVES
WITH THE ELEVATED WARM FRONT MOVING IN THIS MORNING FROM THE
SOUTH. THEREFORE WILL KEEP THE MENTION OF SHOWERS AND
THUNDERSTORMS IN THE FORECAST. LITTLE OR NO FORCING IS AROUND
TONIGHT INTO SUNDAY. WILL KEEP IT DRY FOR NOW. THE ATMOSPHERE
BECOMES RATHER UNSTABLE ON SUNDAY...SO WILL NEED TO MONITOR THIS
CLOSELY. SUNDAY SHOULD BE ONE OF THE WARMEST DAYS OF THE SEASON AS
THE LOW LEVEL THERMAL RIDGE ADVECTS IN FROM THE SOUTHWEST.
WILL FEATURE AN INCREASING RISK FOR SHOWERS AND THUNDERSTORMS ON
LABOR DAY. MODELS VARY ON THE TIMING OF ANY PRECIPITATION. HOWEVER
GIVEN THE APPROACHING FRONT DURING THE AFTERNOON WILL ENCOUNTER AN
UNSTABLE AIRMASS...IS SEEMS THAT A RISK FOR THUNDERSTORMS WILL
EXIST. WILL HIGHLIGHT THE AFTERNOON FOR POSSIBLE THUNDERSTORMS.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 308 AM EDT SAT SEP 5 2015
MAIN FOCUS IS CURRENTLY ON THE THREAT FOR HEAVY RAINFALL MONDAY
NIGHT THROUGH TUESDAY NIGHT WITH SOME TRAINING THUNDERSTORMS
POSSIBLE IN ASSOCIATION WITH MAINLY UNIDIRECTIONAL WINDS IN THE
PROFILE...A VERY MOIST AIRMASS...AND A WARM FRONT LIFTING THROUGH
DURING THIS PERIOD. MANY AREAS NEAR AND NORTH OF I-96 ARE EXPECTED
TO RECEIVE ONE TO TWO INCHES OF RAIN BY WEDNESDAY MORNING WITH
HIGHER AMOUNTS QUITE POSSIBLE.
I BELIEVE THERE ARE SOME KEY INGREDIENTS COMING IN PLACE FOR LOCALLY
EXCESSIVE RAINFALL ACROSS WEST CENTRAL AND SOUTHWEST LOWER MI. AS
HAS BEEN MENTIONED MANY TIMES...A WEAK COLD FRONT WILL WASH OUT
ACROSS THE CWA MONDAY...WHICH WILL BECOME STATIONARY AND THEN LIFT
NORTH AS A WARM FRONT TUESDAY. JUST HOW FAR NORTH THIS BOUNDARY
LIFTS IS QUESTIONABLE GIVEN NUMEROUS AREAS OF CONVECTION THAT COULD
SUPPRESS THE FRONT SOUTHWARD. CURRENTLY FAVORING THE ECMWF WITH THIS
SYSTEM GIVEN A FEW DIFFERENT GYRATIONS NOTED WITH THE GFS RECENTLY
WITH HOW QUICK THE BOUNDARY WILL MOVE THROUGH.
DEEP LAYER RH (H1000-H500) ON TUESDAY COULD TOP 90% FOR A GOOD
PORTION OF THE CWA...ESPECIALLY FROM GRR TO THE NORTH. ALL OF THE
MODELS ARE ALSO SHOWING SOME H1000-H700 WIND CONVERGENCE. A 20 KT
LLJ AT 00Z TUES STRENGTHENS TO 30-35 KT BY 00Z WED. HIGHER UP...WE
WILL BE SQUARELY IN THE RIGHT ENTRANCE REGION OF A 100 KT JET STREAK
AS H500 POSITIVE VORTICITY ADVECTION MOVES INTO THE CWA DURING THE
MORNING AND AFTERNOON HOURS. NEAR THE SURFACE...THE WARM FRONT WILL
BE DRAPED ACROSS THE CWA NEAR GRR AT 12Z TUESDAY...POSSIBLY LIFTING
NORTH TOWARD ROUTE 10 BY 18Z. DEW POINT READINGS AROUND 70 COUPLED
WITH PW VALUES OF 2.00-2.25" STRONGLY SUGGEST ANY STORMS WOULD BE
CAPABLE OF HEAVY DOWNPOURS. IF THE NWP SOLUTIONS CONTINUE SUPPORTING
THESE DETAILS...COULD FORESEE A FLOOD THREAT FOR AREAS THAT GET THE
MOST PERSISTENT RAINS.
IN TERMS OF ANY SEVERE WEATHER THREAT...IT IS UNCLEAR AT THIS TIME.
ONGOING CONVECTION EARLY TUESDAY COULD HAMPER ANY DESTABILIZATION
DURING THE AFTERNOON. SFC BASED CAPE IS NOT MUCH MORE THAN 1000 J/KG
FOR THE AREA ON TUESDAY...THOUGH BULK SHEAR IS LOOKING MUCH BETTER
OFF THE ECMWF AT AROUND 35-40 KTS. IT IS ALSO SHOWING 100-150 M2/S2
OF 0-1 KM HELICITY COURTESY OF THE WARM FRONT NEARBY. NOT OUT OF THE
QUESTION THERE COULD BE SOME STRONGER STORMS CAPABLE OF GUSTY WINDS
AND SOME HAIL IF WE CAN DESTABILIZE SUFFICIENTLY.
BEYOND THIS PERIOD...LOOKING AT A PATTERN CHANGE FOR THE SECOND HALF
OF THE WEEK AND THE WEEKEND IN PARTICULAR. TROPICAL STORM IGNACIO
WILL GET SWEPT UP IN MID LEVEL FLOW OVER THE GULF OF ALASKA.
FOLLOWING THE ECMWF H500 HEIGHT FIELD...THIS HELPS DIG A TROUGH INTO
THE GREAT LAKES FOR FRIDAY AND SATURDAY...WITH CHILLY TEMPS AND
SCATTERED SHOWERS EXPECTED BY SATURDAY WITH HIGHS STRUGGLING INTO
THE 60S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 730 AM EDT SAT SEP 5 2015
SCATTERED THUNDERSTORMS THIS MORNING WILL IMPACT SOME OF THE TAF
SITES AS A WARM FRONT PUSHES NORTH. WIDESPREAD DENSE FOG WILL
LIFT SLOWLY NORTH AND DISSIPATE THIS MORNING. GENERALLY VFR
WEATHER THEN SETS UP IN AN UNSTABLE AIRMASS. SO WILL MAINTAIN A
RISK FOR THUNDERSTORMS...AS VCTS. TONIGHT THE RISK FOR
THUNDERSTORMS LOWERS...BUT WE MAY SEE FOG REFORMING ONCE AGAIN.
&&
.MARINE...
ISSUED AT 308 AM EDT SAT SEP 5 2015
WINDS AND WAVES INCREASE SUNDAY INTO SUNDAY NIGHT AS THE WARM AIR
ADVECTION STRENGTHS AHEAD OF THE APPROACHING COLD FRONT. WILL NEED
TO MONITOR LITTLE AND BIG SABLE POINTS FOR A POSSIBLE SMALL CRAFT
ADVISORY AND ASSOCIATED BEACH HAZARDS. RIGHT NOW I HAVE WAVES
INCREASING TO 2 TO 4 FEET.
&&
.HYDROLOGY...
ISSUED AT 1214 AM EDT SAT SEP 5 2015
LOCALIZED HEAVY RAINFALL HAS FALLEN OVER SOUTHERN PORTIONS OF THE
FORECAST AREA THIS MORNING. RADAR ESTIMATES SHOW MOST OF THE
RAINFALL ALONG AND SOUTH OF I-96 WITH SPOTTY ESTIMATES POSSIBLY
EXCEEDING ONE INCH. THOUGH THIS IS NOT AN IMMEDIATE PLAYER IN ANY
RIVER FLOODING IT COULD PLAY A ROLE IN NEXT WEEKS RAINFALL
POTENTIAL.
A BRIEF DRY PERIOD LATE TONIGHT THROUGH THE EARLY HALF OF MONDAY
WILL HELP IN ALLOWING RUNOFF TO MAKE ITS WAY DOWN STREAMS AND
RIVERS. THIS MAY BE BENEFICIAL IN THE EVENT THAT THE LATE MONDAY
THROUGH WEDNESDAY TIMEFRAME BRINGS HEAVY RAIN. THOUGH QUESTIONS
STILL EXIST IN PLACEMENT...IT IS BECOMING MORE EVIDENT THAT
MOISTURE FLOWS IN THIS DIRECTION AS PWATS APPROACH 2.0 INCHES.
THIS COUPLED WITH THE SLOW MOVEMENT OF THE FRONTAL BOUNDARY MAY
AID IN ROUNDS OF HEAVY RAINFALL ALONG THE BOUNDARY THROUGH
PORTIONS OF THE FORECAST AREA. WHILE EVERYONE HAS THE THE
POTENTIAL TO SEE SOME DECENT RAINFALL...SOME LOCATIONS MAY EASILY
ACCUMULATE AN INCH OR MORE IN OR AROUND THUNDERSTORMS. ANY
PREVIOUS RAINFALL FROM TODAY COULD HAVE DEPOSITED ENOUGH MOISTURE
TO SOUTHERN SECTIONS... ALLOCATING ADDITIONAL RAINFALL MORE SO TO
RUNOFF THAN TO GROUND WATER. SO THE PLACEMENT OF THE HEAVY RAIN
NEXT WEEK IS SOMETHING TO WATCH.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...NJJ
SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...HOVING
AVIATION...MJS
HYDROLOGY...JAM
MARINE...MJS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1039 AM EDT SAT SEP 5 2015
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 308 AM EDT SAT SEP 5 2015
A WARM FRONT WILL LIFT NORTHWARD THROUGH THE REGION TODAY LEADING
TO SOME SHOWERS AND THUNDERSTORMS. HIGH PRESSURE CONTROLS OUR
WEATHER ON SUNDAY WHICH SHOULD END UP A MOSTLY DRY AND VERY WARM
DAY. THE CHANCES FOR SHOWERS AND THUNDERSTORMS WILL INCREASE AS WE
GO THROUGH LABOR DAY AND INTO TUESDAY AS A SLOW MOVING COLD FRONT
NEARS FROM THE WEST. THE TEMPERATURES WILL STILL END UP WELL ABOVE
NORMAL EARLY NEXT WEEK.
&&
.UPDATE...
ISSUED AT 1039 AM EDT SAT SEP 5 2015
WE HAVE UPDATED TO FCST THIS MORNING TO EXTEND THE DENSE FOG
ADVISORY UNTIL NOON UP NORTH. WE HAVE ALSO INCREASED THE
SHOWER/STORM CHCS DOWN SOUTH WITH PLENTY OF COVERAGE ALREADY IN
PLACE DOWN THERE.
THE FOG UP NORTH HAS BEEN SLOW TO DISSIPATE THIS MORNING WITH MANY
LOCATIONS STILL AT 1/4SM OR LESS LEADING UP TO THE INITIAL
EXPIRATION TIME OF 10 AM THIS MORNING. WITH A LACK OF WIND TO MIX
THINGS UP AND PLENTY OF STRATUS IN PLACE...IT WILL TAKE A LITTLE
LONGER THAN PREVIOUSLY EXPECTED TO MIX IT OUT. WE GAVE IT UNTIL
NOON FOR MORE OF A BUFFER. WE WILL CANCEL IT EARLY IF ALL SITES
COME UP SOONER.
PLENTY OF SHOWERS AND STORMS ACROSS THE SOUTH THIS MORNING. THE
PESKY WEAK UPPER LOW THAT HAS BEEN MEANDERING ACROSS THE STATE THE
PAST COUPLE OF DAYS IS OVER LAKE MICHIGAN EARLY THIS MORNING. IT
NOW LOOKS LIKE IT IS MAKING A MOVE TO THE EAST...AND FIRING PLENTY
OF SHOWERS/STORMS AHEAD OF IT WITH THE MOIST AIR MASS IN PLACE.
IT APPEARS THIS WILL CONTINUE EAST THROUGH THE DAY AND PUSH THE
MORE WIDESPREAD COVERAGE EAST BY LATER THIS AFTERNOON. WE CAN NOT
RULE OUT A POP UP SHOWER/STORM WITH THE UPPER LOW STILL NEARBY.
WEAK SHEAR AND LIMITED INSTABILITY WILL KEEP THINGS GENERALLY
TAME. HEAVY DOWNPOURS WOULD BE THE GREATEST THREAT WITH THE SLOW
MOVEMENT.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 308 AM EDT SAT SEP 5 2015
DENSE FOG HAS BEEN INCREASING OVER THE PAST FEW HOURS AND NOW
COVERS MUCH OF THE REGION. HRRR RUC SUGGESTS THE FOG WILL PERSIST
THROUGH DAYBREAK. WILL GO WITH AN ADVISORY AND CARRY IT UNTIL MID
MORNING. WE MAY SEE GRADUAL IMPROVEMENT IN THE VISIBILITIES FROM
SOUTH TO NORTH BEFORE DAYBREAK AS THE ELEVATED WARM FRONT MOVES
IN.
THE ATMOSPHERE WILL BE UNSTABLE THROUGH THE DAY. SOME LIFT ARRIVES
WITH THE ELEVATED WARM FRONT MOVING IN THIS MORNING FROM THE
SOUTH. THEREFORE WILL KEEP THE MENTION OF SHOWERS AND
THUNDERSTORMS IN THE FORECAST. LITTLE OR NO FORCING IS AROUND
TONIGHT INTO SUNDAY. WILL KEEP IT DRY FOR NOW. THE ATMOSPHERE
BECOMES RATHER UNSTABLE ON SUNDAY...SO WILL NEED TO MONITOR THIS
CLOSELY. SUNDAY SHOULD BE ONE OF THE WARMEST DAYS OF THE SEASON AS
THE LOW LEVEL THERMAL RIDGE ADVECTS IN FROM THE SOUTHWEST.
WILL FEATURE AN INCREASING RISK FOR SHOWERS AND THUNDERSTORMS ON
LABOR DAY. MODELS VARY ON THE TIMING OF ANY PRECIPITATION. HOWEVER
GIVEN THE APPROACHING FRONT DURING THE AFTERNOON WILL ENCOUNTER AN
UNSTABLE AIRMASS...IS SEEMS THAT A RISK FOR THUNDERSTORMS WILL
EXIST. WILL HIGHLIGHT THE AFTERNOON FOR POSSIBLE THUNDERSTORMS.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 308 AM EDT SAT SEP 5 2015
MAIN FOCUS IS CURRENTLY ON THE THREAT FOR HEAVY RAINFALL MONDAY
NIGHT THROUGH TUESDAY NIGHT WITH SOME TRAINING THUNDERSTORMS
POSSIBLE IN ASSOCIATION WITH MAINLY UNIDIRECTIONAL WINDS IN THE
PROFILE...A VERY MOIST AIRMASS...AND A WARM FRONT LIFTING THROUGH
DURING THIS PERIOD. MANY AREAS NEAR AND NORTH OF I-96 ARE EXPECTED
TO RECEIVE ONE TO TWO INCHES OF RAIN BY WEDNESDAY MORNING WITH
HIGHER AMOUNTS QUITE POSSIBLE.
I BELIEVE THERE ARE SOME KEY INGREDIENTS COMING IN PLACE FOR LOCALLY
EXCESSIVE RAINFALL ACROSS WEST CENTRAL AND SOUTHWEST LOWER MI. AS
HAS BEEN MENTIONED MANY TIMES...A WEAK COLD FRONT WILL WASH OUT
ACROSS THE CWA MONDAY...WHICH WILL BECOME STATIONARY AND THEN LIFT
NORTH AS A WARM FRONT TUESDAY. JUST HOW FAR NORTH THIS BOUNDARY
LIFTS IS QUESTIONABLE GIVEN NUMEROUS AREAS OF CONVECTION THAT COULD
SUPPRESS THE FRONT SOUTHWARD. CURRENTLY FAVORING THE ECMWF WITH THIS
SYSTEM GIVEN A FEW DIFFERENT GYRATIONS NOTED WITH THE GFS RECENTLY
WITH HOW QUICK THE BOUNDARY WILL MOVE THROUGH.
DEEP LAYER RH (H1000-H500) ON TUESDAY COULD TOP 90% FOR A GOOD
PORTION OF THE CWA...ESPECIALLY FROM GRR TO THE NORTH. ALL OF THE
MODELS ARE ALSO SHOWING SOME H1000-H700 WIND CONVERGENCE. A 20 KT
LLJ AT 00Z TUES STRENGTHENS TO 30-35 KT BY 00Z WED. HIGHER UP...WE
WILL BE SQUARELY IN THE RIGHT ENTRANCE REGION OF A 100 KT JET STREAK
AS H500 POSITIVE VORTICITY ADVECTION MOVES INTO THE CWA DURING THE
MORNING AND AFTERNOON HOURS. NEAR THE SURFACE...THE WARM FRONT WILL
BE DRAPED ACROSS THE CWA NEAR GRR AT 12Z TUESDAY...POSSIBLY LIFTING
NORTH TOWARD ROUTE 10 BY 18Z. DEW POINT READINGS AROUND 70 COUPLED
WITH PW VALUES OF 2.00-2.25" STRONGLY SUGGEST ANY STORMS WOULD BE
CAPABLE OF HEAVY DOWNPOURS. IF THE NWP SOLUTIONS CONTINUE SUPPORTING
THESE DETAILS...COULD FORESEE A FLOOD THREAT FOR AREAS THAT GET THE
MOST PERSISTENT RAINS.
IN TERMS OF ANY SEVERE WEATHER THREAT...IT IS UNCLEAR AT THIS TIME.
ONGOING CONVECTION EARLY TUESDAY COULD HAMPER ANY DESTABILIZATION
DURING THE AFTERNOON. SFC BASED CAPE IS NOT MUCH MORE THAN 1000 J/KG
FOR THE AREA ON TUESDAY...THOUGH BULK SHEAR IS LOOKING MUCH BETTER
OFF THE ECMWF AT AROUND 35-40 KTS. IT IS ALSO SHOWING 100-150 M2/S2
OF 0-1 KM HELICITY COURTESY OF THE WARM FRONT NEARBY. NOT OUT OF THE
QUESTION THERE COULD BE SOME STRONGER STORMS CAPABLE OF GUSTY WINDS
AND SOME HAIL IF WE CAN DESTABILIZE SUFFICIENTLY.
BEYOND THIS PERIOD...LOOKING AT A PATTERN CHANGE FOR THE SECOND HALF
OF THE WEEK AND THE WEEKEND IN PARTICULAR. TROPICAL STORM IGNACIO
WILL GET SWEPT UP IN MID LEVEL FLOW OVER THE GULF OF ALASKA.
FOLLOWING THE ECMWF H500 HEIGHT FIELD...THIS HELPS DIG A TROUGH INTO
THE GREAT LAKES FOR FRIDAY AND SATURDAY...WITH CHILLY TEMPS AND
SCATTERED SHOWERS EXPECTED BY SATURDAY WITH HIGHS STRUGGLING INTO
THE 60S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 730 AM EDT SAT SEP 5 2015
SCATTERED THUNDERSTORMS THIS MORNING WILL IMPACT SOME OF THE TAF
SITES AS A WARM FRONT PUSHES NORTH. WIDESPREAD DENSE FOG WILL
LIFT SLOWLY NORTH AND DISSIPATE THIS MORNING. GENERALLY VFR
WEATHER THEN SETS UP IN AN UNSTABLE AIRMASS. SO WILL MAINTAIN A
RISK FOR THUNDERSTORMS...AS VCTS. TONIGHT THE RISK FOR
THUNDERSTORMS LOWERS...BUT WE MAY SEE FOG REFORMING ONCE AGAIN.
&&
.MARINE...
ISSUED AT 308 AM EDT SAT SEP 5 2015
WINDS AND WAVES INCREASE SUNDAY INTO SUNDAY NIGHT AS THE WARM AIR
ADVECTION STRENGTHS AHEAD OF THE APPROACHING COLD FRONT. WILL NEED
TO MONITOR LITTLE AND BIG SABLE POINTS FOR A POSSIBLE SMALL CRAFT
ADVISORY AND ASSOCIATED BEACH HAZARDS. RIGHT NOW I HAVE WAVES
INCREASING TO 2 TO 4 FEET.
&&
.HYDROLOGY...
ISSUED AT 1054 AM EDT FRI SEP 4 2015
NO CONCERNS EXIST IN THE NEAR TERM. QUESTIONS ARISE GOING INTO NEXT
WEEK AS A BOUNDARY DRAPES ITSELF SOMEWHERE THROUGH OR NEAR THE GREAT
LAKES REGION.
AREA RIVERS HAVE RESPONDED PRETTY WELL TO YESTERDAYS RAINFALL.
LOCALIZED TOTALS OF MORE THAN TWO INCHES RESULTED IN DECENT UPWARD
TRENDS AT A FEW FORECAST POINTS. MOST NOTABLE IS SYCAMORE CREEK AT
HOLT...WHICH HAS LEVELED OFF ABOUT A FOOT BELOW ADVISORY CRITERIA.
PROVIDED THAT ADDITIONAL RAINFALL IS LIMITED...HOLT SHOULD CONTINUE
ITS DOWNWARD TREND. OTHER SITES HAVE ALSO LEVELED OFF AND RESPONSES
HAVE BEEN MINOR.
RAINFALL THROUGH THE WEEKEND IS EXPECTED TO BE SCATTERED WITH
LOCALIZED HEAVY RAIN POSSIBLE IN OR AROUND THUNDERSTORMS. CONDITIONS
ARE NOT FAVORABLE FOR WIDESPREAD HEAVY RAIN. A PATTERN CHANGE WILL
TAKE PLACE NEXT WEEK AND ITS ASSOCIATED BOUNDARY LOOKS TO BE MOVING
SLOWLY. DIFFERENCES IN LONG RANGE MODELS PUT A CAP ON ANY HIGH
CONFIDENCE. HOWEVER...PWATS ARE 1.5-2.0 INCHES AND THE SLOW
PROGRESSION OF THE BOUNDARY COULD RESULT IN PRETTY DECENT RAINFALL
TOTALS MONDAY THROUGH WEDNESDAY. THE SETUP MAY SUGGEST MORE THAN AN
INCH...WITH AREAS EXCEEDING A COUPLE OF INCHES IF STORMS ARE SLOW
MOVERS. THIS WILL LIKELY BE THE FOCUS HYDRO-WISE OVER THE NEXT
FEW DAYS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...DENSE FOG ADVISORY UNTIL NOON EDT TODAY FOR MIZ037>040-043>046-
050>052.
LM...NONE.
&&
$$
UPDATE...NJJ
SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...HOVING
AVIATION...MJS
HYDROLOGY...JAM
MARINE...MJS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
734 AM EDT SAT SEP 5 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 308 AM EDT SAT SEP 5 2015
A WARM FRONT WILL LIFT NORTHWARD THROUGH THE REGION TODAY LEADING
TO SOME SHOWERS AND THUNDERSTORMS. HIGH PRESSURE CONTROLS OUR
WEATHER ON SUNDAY WHICH SHOULD END UP A MOSTLY DRY AND VERY WARM
DAY. THE CHANCES FOR SHOWERS AND THUNDERSTORMS WILL INCREASE AS WE
GO THROUGH LABOR DAY AND INTO TUESDAY AS A SLOW MOVING COLD FRONT
NEARS FROM THE WEST. THE TEMPERATURES WILL STILL END UP WELL ABOVE
NORMAL EARLY NEXT WEEK.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 308 AM EDT SAT SEP 5 2015
DENSE FOG HAS BEEN INCREASING OVER THE PAST FEW HOURS AND NOW
COVERS MUCH OF THE REGION. HRRR RUC SUGGESTS THE FOG WILL PERSIST
THROUGH DAYBREAK. WILL GO WITH AN ADVISORY AND CARRY IT UNTIL MID
MORNING. WE MAY SEE GRADUAL IMPROVEMENT IN THE VISIBILITIES FROM
SOUTH TO NORTH BEFORE DAYBREAK AS THE ELEVATED WARM FRONT MOVES
IN.
THE ATMOSPHERE WILL BE UNSTABLE THROUGH THE DAY. SOME LIFT ARRIVES
WITH THE ELEVATED WARM FRONT MOVING IN THIS MORNING FROM THE
SOUTH. THEREFORE WILL KEEP THE MENTION OF SHOWERS AND
THUNDERSTORMS IN THE FORECAST. LITTLE OR NO FORCING IS AROUND
TONIGHT INTO SUNDAY. WILL KEEP IT DRY FOR NOW. THE ATMOSPHERE
BECOMES RATHER UNSTABLE ON SUNDAY...SO WILL NEED TO MONITOR THIS
CLOSELY. SUNDAY SHOULD BE ONE OF THE WARMEST DAYS OF THE SEASON AS
THE LOW LEVEL THERMAL RIDGE ADVECTS IN FROM THE SOUTHWEST.
WILL FEATURE AN INCREASING RISK FOR SHOWERS AND THUNDERSTORMS ON
LABOR DAY. MODELS VARY ON THE TIMING OF ANY PRECIPITATION. HOWEVER
GIVEN THE APPROACHING FRONT DURING THE AFTERNOON WILL ENCOUNTER AN
UNSTABLE AIRMASS...IS SEEMS THAT A RISK FOR THUNDERSTORMS WILL
EXIST. WILL HIGHLIGHT THE AFTERNOON FOR POSSIBLE THUNDERSTORMS.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 308 AM EDT SAT SEP 5 2015
MAIN FOCUS IS CURRENTLY ON THE THREAT FOR HEAVY RAINFALL MONDAY
NIGHT THROUGH TUESDAY NIGHT WITH SOME TRAINING THUNDERSTORMS
POSSIBLE IN ASSOCIATION WITH MAINLY UNIDIRECTIONAL WINDS IN THE
PROFILE...A VERY MOIST AIRMASS...AND A WARM FRONT LIFTING THROUGH
DURING THIS PERIOD. MANY AREAS NEAR AND NORTH OF I-96 ARE EXPECTED
TO RECEIVE ONE TO TWO INCHES OF RAIN BY WEDNESDAY MORNING WITH
HIGHER AMOUNTS QUITE POSSIBLE.
I BELIEVE THERE ARE SOME KEY INGREDIENTS COMING IN PLACE FOR LOCALLY
EXCESSIVE RAINFALL ACROSS WEST CENTRAL AND SOUTHWEST LOWER MI. AS
HAS BEEN MENTIONED MANY TIMES...A WEAK COLD FRONT WILL WASH OUT
ACROSS THE CWA MONDAY...WHICH WILL BECOME STATIONARY AND THEN LIFT
NORTH AS A WARM FRONT TUESDAY. JUST HOW FAR NORTH THIS BOUNDARY
LIFTS IS QUESTIONABLE GIVEN NUMEROUS AREAS OF CONVECTION THAT COULD
SUPPRESS THE FRONT SOUTHWARD. CURRENTLY FAVORING THE ECMWF WITH THIS
SYSTEM GIVEN A FEW DIFFERENT GYRATIONS NOTED WITH THE GFS RECENTLY
WITH HOW QUICK THE BOUNDARY WILL MOVE THROUGH.
DEEP LAYER RH (H1000-H500) ON TUESDAY COULD TOP 90% FOR A GOOD
PORTION OF THE CWA...ESPECIALLY FROM GRR TO THE NORTH. ALL OF THE
MODELS ARE ALSO SHOWING SOME H1000-H700 WIND CONVERGENCE. A 20 KT
LLJ AT 00Z TUES STRENGTHENS TO 30-35 KT BY 00Z WED. HIGHER UP...WE
WILL BE SQUARELY IN THE RIGHT ENTRANCE REGION OF A 100 KT JET STREAK
AS H500 POSITIVE VORTICITY ADVECTION MOVES INTO THE CWA DURING THE
MORNING AND AFTERNOON HOURS. NEAR THE SURFACE...THE WARM FRONT WILL
BE DRAPED ACROSS THE CWA NEAR GRR AT 12Z TUESDAY...POSSIBLY LIFTING
NORTH TOWARD ROUTE 10 BY 18Z. DEW POINT READINGS AROUND 70 COUPLED
WITH PW VALUES OF 2.00-2.25" STRONGLY SUGGEST ANY STORMS WOULD BE
CAPABLE OF HEAVY DOWNPOURS. IF THE NWP SOLUTIONS CONTINUE SUPPORTING
THESE DETAILS...COULD FORESEE A FLOOD THREAT FOR AREAS THAT GET THE
MOST PERSISTENT RAINS.
IN TERMS OF ANY SEVERE WEATHER THREAT...IT IS UNCLEAR AT THIS TIME.
ONGOING CONVECTION EARLY TUESDAY COULD HAMPER ANY DESTABILIZATION
DURING THE AFTERNOON. SFC BASED CAPE IS NOT MUCH MORE THAN 1000 J/KG
FOR THE AREA ON TUESDAY...THOUGH BULK SHEAR IS LOOKING MUCH BETTER
OFF THE ECMWF AT AROUND 35-40 KTS. IT IS ALSO SHOWING 100-150 M2/S2
OF 0-1 KM HELICITY COURTESY OF THE WARM FRONT NEARBY. NOT OUT OF THE
QUESTION THERE COULD BE SOME STRONGER STORMS CAPABLE OF GUSTY WINDS
AND SOME HAIL IF WE CAN DESTABILIZE SUFFICIENTLY.
BEYOND THIS PERIOD...LOOKING AT A PATTERN CHANGE FOR THE SECOND HALF
OF THE WEEK AND THE WEEKEND IN PARTICULAR. TROPICAL STORM IGNACIO
WILL GET SWEPT UP IN MID LEVEL FLOW OVER THE GULF OF ALASKA.
FOLLOWING THE ECMWF H500 HEIGHT FIELD...THIS HELPS DIG A TROUGH INTO
THE GREAT LAKES FOR FRIDAY AND SATURDAY...WITH CHILLY TEMPS AND
SCATTERED SHOWERS EXPECTED BY SATURDAY WITH HIGHS STRUGGLING INTO
THE 60S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 730 AM EDT SAT SEP 5 2015
SCATTERED THUNDERSTORMS THIS MORNING WILL IMPACT SOME OF THE TAF
SITES AS A WARM FRONT PUSHES NORTH. WIDESPREAD DENSE FOG WILL
LIFT SLOWLY NORTH AND DISSIPATE THIS MORNING. GENERALLY VFR
WEATHER THEN SETS UP IN AN UNSTABLE AIRMASS. SO WILL MAINTAIN A
RISK FOR THUNDERSTORMS...AS VCTS. TONIGHT THE RISK FOR
THUNDERSTORMS LOWERS...BUT WE MAY SEE FOG REFORMING ONCE AGAIN.
&&
.MARINE...
ISSUED AT 308 AM EDT SAT SEP 5 2015
WINDS AND WAVES INCREASE SUNDAY INTO SUNDAY NIGHT AS THE WARM AIR
ADVECTION STRENGTHS AHEAD OF THE APPROACHING COLD FRONT. WILL NEED
TO MONITOR LITTLE AND BIG SABLE POINTS FOR A POSSIBLE SMALL CRAFT
ADVISORY AND ASSOCIATED BEACH HAZARDS. RIGHT NOW I HAVE WAVES
INCREASING TO 2 TO 4 FEET.
&&
.HYDROLOGY...
ISSUED AT 1054 AM EDT FRI SEP 4 2015
NO CONCERNS EXIST IN THE NEAR TERM. QUESTIONS ARISE GOING INTO NEXT
WEEK AS A BOUNDARY DRAPES ITSELF SOMEWHERE THROUGH OR NEAR THE GREAT
LAKES REGION.
AREA RIVERS HAVE RESPONDED PRETTY WELL TO YESTERDAYS RAINFALL.
LOCALIZED TOTALS OF MORE THAN TWO INCHES RESULTED IN DECENT UPWARD
TRENDS AT A FEW FORECAST POINTS. MOST NOTABLE IS SYCAMORE CREEK AT
HOLT...WHICH HAS LEVELED OFF ABOUT A FOOT BELOW ADVISORY CRITERIA.
PROVIDED THAT ADDITIONAL RAINFALL IS LIMITED...HOLT SHOULD CONTINUE
ITS DOWNWARD TREND. OTHER SITES HAVE ALSO LEVELED OFF AND RESPONSES
HAVE BEEN MINOR.
RAINFALL THROUGH THE WEEKEND IS EXPECTED TO BE SCATTERED WITH
LOCALIZED HEAVY RAIN POSSIBLE IN OR AROUND THUNDERSTORMS. CONDITIONS
ARE NOT FAVORABLE FOR WIDESPREAD HEAVY RAIN. A PATTERN CHANGE WILL
TAKE PLACE NEXT WEEK AND ITS ASSOCIATED BOUNDARY LOOKS TO BE MOVING
SLOWLY. DIFFERENCES IN LONG RANGE MODELS PUT A CAP ON ANY HIGH
CONFIDENCE. HOWEVER...PWATS ARE 1.5-2.0 INCHES AND THE SLOW
PROGRESSION OF THE BOUNDARY COULD RESULT IN PRETTY DECENT RAINFALL
TOTALS MONDAY THROUGH WEDNESDAY. THE SETUP MAY SUGGEST MORE THAN AN
INCH...WITH AREAS EXCEEDING A COUPLE OF INCHES IF STORMS ARE SLOW
MOVERS. THIS WILL LIKELY BE THE FOCUS HYDRO-WISE OVER THE NEXT
FEW DAYS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR MIZ037>040-
043>046-050>052-056>059-064>067.
LM...NONE.
&&
$$
SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...HOVING
AVIATION...MJS
HYDROLOGY...JAM
MARINE...MJS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
325 AM EDT SAT SEP 5 2015
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/MARINE
.SYNOPSIS...
ISSUED AT 308 AM EDT SAT SEP 5 2015
A WARM FRONT WILL LIFT NORTHWARD THROUGH THE REGION TODAY LEADING
TO SOME SHOWERS AND THUNDERSTORMS. HIGH PRESSURE CONTROLS OUR
WEATHER ON SUNDAY WHICH SHOULD END UP A MOSTLY DRY AND VERY WARM
DAY. THE CHANCES FOR SHOWERS AND THUNDERSTORMS WILL INCREASE AS WE
GO THROUGH LABOR DAY AND INTO TUESDAY AS A SLOW MOVING COLD FRONT
NEARS FROM THE WEST. THE TEMPERATURES WILL STILL END UP WELL ABOVE
NORMAL EARLY NEXT WEEK.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 308 AM EDT SAT SEP 5 2015
DENSE FOG HAS BEEN INCREASING OVER THE PAST FEW HOURS AND NOW
COVERS MUCH OF THE REGION. HRRR RUC SUGGESTS THE FOG WILL PERSIST
THROUGH DAYBREAK. WILL GO WITH AN ADVISORY AND CARRY IT UNTIL MID
MORNING. WE MAY SEE GRADUAL IMPROVEMENT IN THE VISIBILITIES FROM
SOUTH TO NORTH BEFORE DAYBREAK AS THE ELEVATED WARM FRONT MOVES
IN.
THE ATMOSPHERE WILL BE UNSTABLE THROUGH THE DAY. SOME LIFT ARRIVES
WITH THE ELEVATED WARM FRONT MOVING IN THIS MORNING FROM THE
SOUTH. THEREFORE WILL KEEP THE MENTION OF SHOWERS AND
THUNDERSTORMS IN THE FORECAST. LITTLE OR NO FORCING IS AROUND
TONIGHT INTO SUNDAY. WILL KEEP IT DRY FOR NOW. THE ATMOSPHERE
BECOMES RATHER UNSTABLE ON SUNDAY...SO WILL NEED TO MONITOR THIS
CLOSELY. SUNDAY SHOULD BE ONE OF THE WARMEST DAYS OF THE SEASON AS
THE LOW LEVEL THERMAL RIDGE ADVECTS IN FROM THE SOUTHWEST.
WILL FEATURE AN INCREASING RISK FOR SHOWERS AND THUNDERSTORMS ON
LABOR DAY. MODELS VARY ON THE TIMING OF ANY PRECIPITATION. HOWEVER
GIVEN THE APPROACHING FRONT DURING THE AFTERNOON WILL ENCOUNTER AN
UNSTABLE AIRMASS...IS SEEMS THAT A RISK FOR THUNDERSTORMS WILL
EXIST. WILL HIGHLIGHT THE AFTERNOON FOR POSSIBLE THUNDERSTORMS.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 308 AM EDT SAT SEP 5 2015
MAIN FOCUS IS CURRENTLY ON THE THREAT FOR HEAVY RAINFALL MONDAY
NIGHT THROUGH TUESDAY NIGHT WITH SOME TRAINING THUNDERSTORMS
POSSIBLE IN ASSOCIATION WITH MAINLY UNIDIRECTIONAL WINDS IN THE
PROFILE...A VERY MOIST AIRMASS...AND A WARM FRONT LIFTING THROUGH
DURING THIS PERIOD. MANY AREAS NEAR AND NORTH OF I-96 ARE EXPECTED
TO RECEIVE ONE TO TWO INCHES OF RAIN BY WEDNESDAY MORNING WITH
HIGHER AMOUNTS QUITE POSSIBLE.
I BELIEVE THERE ARE SOME KEY INGREDIENTS COMING IN PLACE FOR LOCALLY
EXCESSIVE RAINFALL ACROSS WEST CENTRAL AND SOUTHWEST LOWER MI. AS
HAS BEEN MENTIONED MANY TIMES...A WEAK COLD FRONT WILL WASH OUT
ACROSS THE CWA MONDAY...WHICH WILL BECOME STATIONARY AND THEN LIFT
NORTH AS A WARM FRONT TUESDAY. JUST HOW FAR NORTH THIS BOUNDARY
LIFTS IS QUESTIONABLE GIVEN NUMEROUS AREAS OF CONVECTION THAT COULD
SUPPRESS THE FRONT SOUTHWARD. CURRENTLY FAVORING THE ECMWF WITH THIS
SYSTEM GIVEN A FEW DIFFERENT GYRATIONS NOTED WITH THE GFS RECENTLY
WITH HOW QUICK THE BOUNDARY WILL MOVE THROUGH.
DEEP LAYER RH (H1000-H500) ON TUESDAY COULD TOP 90% FOR A GOOD
PORTION OF THE CWA...ESPECIALLY FROM GRR TO THE NORTH. ALL OF THE
MODELS ARE ALSO SHOWING SOME H1000-H700 WIND CONVERGENCE. A 20 KT
LLJ AT 00Z TUES STRENGTHENS TO 30-35 KT BY 00Z WED. HIGHER UP...WE
WILL BE SQUARELY IN THE RIGHT ENTRANCE REGION OF A 100 KT JET STREAK
AS H500 POSITIVE VORTICITY ADVECTION MOVES INTO THE CWA DURING THE
MORNING AND AFTERNOON HOURS. NEAR THE SURFACE...THE WARM FRONT WILL
BE DRAPED ACROSS THE CWA NEAR GRR AT 12Z TUESDAY...POSSIBLY LIFTING
NORTH TOWARD ROUTE 10 BY 18Z. DEW POINT READINGS AROUND 70 COUPLED
WITH PW VALUES OF 2.00-2.25" STRONGLY SUGGEST ANY STORMS WOULD BE
CAPABLE OF HEAVY DOWNPOURS. IF THE NWP SOLUTIONS CONTINUE SUPPORTING
THESE DETAILS...COULD FORESEE A FLOOD THREAT FOR AREAS THAT GET THE
MOST PERSISTENT RAINS.
IN TERMS OF ANY SEVERE WEATHER THREAT...IT IS UNCLEAR AT THIS TIME.
ONGOING CONVECTION EARLY TUESDAY COULD HAMPER ANY DESTABILIZATION
DURING THE AFTERNOON. SFC BASED CAPE IS NOT MUCH MORE THAN 1000 J/KG
FOR THE AREA ON TUESDAY...THOUGH BULK SHEAR IS LOOKING MUCH BETTER
OFF THE ECMWF AT AROUND 35-40 KTS. IT IS ALSO SHOWING 100-150 M2/S2
OF 0-1 KM HELICITY COURTESY OF THE WARM FRONT NEARBY. NOT OUT OF THE
QUESTION THERE COULD BE SOME STRONGER STORMS CAPABLE OF GUSTY WINDS
AND SOME HAIL IF WE CAN DESTABILIZE SUFFICIENTLY.
BEYOND THIS PERIOD...LOOKING AT A PATTERN CHANGE FOR THE SECOND HALF
OF THE WEEK AND THE WEEKEND IN PARTICULAR. TROPICAL STORM IGNACIO
WILL GET SWEPT UP IN MID LEVEL FLOW OVER THE GULF OF ALASKA.
FOLLOWING THE ECMWF H500 HEIGHT FIELD...THIS HELPS DIG A TROUGH INTO
THE GREAT LAKES FOR FRIDAY AND SATURDAY...WITH CHILLY TEMPS AND
SCATTERED SHOWERS EXPECTED BY SATURDAY WITH HIGHS STRUGGLING INTO
THE 60S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 142 AM EDT SAT SEP 5 2015
AREAS OF FOG WILL LIKELY BE IN AND OUT OF THE TAF SITES THROUGH
12Z OR 13Z. ABRUPT CHANGES IN VIS/CIG CAN BE EXPECTED AS THE FOG
DEVELOPS MAINLY NORTH OF THE AZO/BTL TERMINALS WHERE MORE CLEARING
HAS OCCURRED. VCTS THREAT EXISTS THIS MORNING MAINLY FOR AZO/BTL
PER HIGH RES MODEL GUIDANCE AND RADAR COLLABORATION. DAYTIME POP-
UP STORMS ARE POSSIBLE JUST ABOUT ANYWHERE TODAY WITH THE THREAT
ENDING CLOSE TO DARK.
&&
.MARINE...
ISSUED AT 308 AM EDT SAT SEP 5 2015
WINDS AND WAVES INCREASE SUNDAY INTO SUNDAY NIGHT AS THE WARM AIR
ADVECTION STRENGTHS AHEAD OF THE APPROACHING COLD FRONT. WILL NEED
TO MONITOR LITTLE AND BIG SABLE POINTS FOR A POSSIBLE SMALL CRAFT
ADVISORY AND ASSOCIATED BEACH HAZARDS. RIGHT NOW I HAVE WAVES
INCREASING TO 2 TO 4 FEET.
&&
.HYDROLOGY...
ISSUED AT 1054 AM EDT FRI SEP 4 2015
NO CONCERNS EXIST IN THE NEAR TERM. QUESTIONS ARISE GOING INTO NEXT
WEEK AS A BOUNDARY DRAPES ITSELF SOMEWHERE THROUGH OR NEAR THE GREAT
LAKES REGION.
AREA RIVERS HAVE RESPONDED PRETTY WELL TO YESTERDAYS RAINFALL.
LOCALIZED TOTALS OF MORE THAN TWO INCHES RESULTED IN DECENT UPWARD
TRENDS AT A FEW FORECAST POINTS. MOST NOTABLE IS SYCAMORE CREEK AT
HOLT...WHICH HAS LEVELED OFF ABOUT A FOOT BELOW ADVISORY CRITERIA.
PROVIDED THAT ADDITIONAL RAINFALL IS LIMITED...HOLT SHOULD CONTINUE
ITS DOWNWARD TREND. OTHER SITES HAVE ALSO LEVELED OFF AND RESPONSES
HAVE BEEN MINOR.
RAINFALL THROUGH THE WEEKEND IS EXPECTED TO BE SCATTERED WITH
LOCALIZED HEAVY RAIN POSSIBLE IN OR AROUND THUNDERSTORMS. CONDITIONS
ARE NOT FAVORABLE FOR WIDESPREAD HEAVY RAIN. A PATTERN CHANGE WILL
TAKE PLACE NEXT WEEK AND ITS ASSOCIATED BOUNDARY LOOKS TO BE MOVING
SLOWLY. DIFFERENCES IN LONG RANGE MODELS PUT A CAP ON ANY HIGH
CONFIDENCE. HOWEVER...PWATS ARE 1.5-2.0 INCHES AND THE SLOW
PROGRESSION OF THE BOUNDARY COULD RESULT IN PRETTY DECENT RAINFALL
TOTALS MONDAY THROUGH WEDNESDAY. THE SETUP MAY SUGGEST MORE THAN AN
INCH...WITH AREAS EXCEEDING A COUPLE OF INCHES IF STORMS ARE SLOW
MOVERS. THIS WILL LIKELY BE THE FOCUS HYDRO-WISE OVER THE NEXT
FEW DAYS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR MIZ037>040-
043>046-050>052-056>059-064>067.
LM...NONE.
&&
$$
SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...HOVING
AVIATION...HOVING
HYDROLOGY...JAM
MARINE...MJS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
145 AM EDT SAT SEP 5 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 323 PM EDT FRI SEP 4 2015
A WEAK LOW PRESSURE AREA WILL HELP TRIGGER SHOWERS AND POSSIBLY A
THUNDERSTORM THIS EVENING INTO EARLY TONIGHT OVER NORTHERN LOWER
MICHIGAN AS IT DRIFTS NORTHWARD. BEHIND IT...WARM AND HUMID AIR WILL
RETURN FROM THE SOUTH WITH SLIGHT CHANCES FOR SHOWERS AND
THUNDERSTORMS. SUNDAY WILL BE HOT AND DRY WITH HIGHS NEAR 90. THIS
WILL BE FOLLOWED BY A WET PERIOD LASTING LABOR DAY THROUGH TUESDAY
AS A COLD FRONT PASSES. BEHIND THIS FRONT...THE LATTER HALF OF THE
WORK WEEK WILL FEATURE MUCH DRIER CONDITIONS AND HIGHS IN THE LOW TO
MID 70S.
&&
.UPDATE...
ISSUED AT 1049 PM EDT FRI SEP 4 2015
DID NOT MAKE BIG CHANGES TO THE FORECAST...BUT DID ADD AREAS OF
FOG WORDING VERSUS PATCHY AS WE SHOULD SEE FOG IN MANY AREAS.
MASON AND CHARLOTTE HAVE ALREADY HAD VISIBILITIES DIP TO AROUND 1
MILE. EXPECTING FOG TO BECOME MORE PREVALENT THROUGH THE NIGHT
GIVEN LIGHT WINDS AND A MOIST AIR MASS.
AS FOR PRECIP CHANCES...FEEL WE MAY SEE ISOLATED TO SCATTERED
SHOWERS AND STORMS DEVELOP NEAR AND ESPECIALLY SOUTH OF INTERSTATE
96. THE RAP13 MODEL AS WELL AS THE NAM ARE INDICATING A WEAK LLJ
DEVELOPING ALONG WITH SOME MODEST 850MB MOISTURE TRANSPORT. THE
SOUTHERN CWA WILL BE NEAR A WEAK 850MB WARM FRONTAL FEATURE THAT
CAN BE SEEN IN THE 850MB DEW POINT FIELDS. HAVE ISOLATED SHOWERS
POSSIBLE NORTH WITH ISOLATED SHOWERS AND STORMS TO THE SOUTH.
LATEST RUN OF THE HRRR HAS THE SHOWERS AND STORMS DEVELOPING
TOWARD INTERSTATE 94 AROUND DAYBREAK. OTHER CONVECTION ALLOWING
MODELS HAVE ACTIVITY DEVELOPING SOONER IN THE NIGHT. NOTHING
STRONG...BUT WE WILL BE KEEPING AN EYE ON THE RADAR OVERNIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 323 PM EDT FRI SEP 4 2015
CONTINUED TO TRIM RAIN CHANCES FOR THIS EVENING AND EARLY TONIGHT AS
LOW LEVEL FORCING CONTINUES WITH SURFACE LOW DRIFTING NORTH. SOME
CONVECTION ALLOWING MODELS SUGGEST SHOWERS AND THUNDERSTORMS WILL
DEVELOP OR SPREAD NORTH TOWARDS THE I-94 CORRIDOR SATURDAY
MORNING...POSSIBLY ASSOCIATED WITH REMNANTS OF THE ONGOING
CONVECTION ACROSS NORTHERN INDIANA. ALSO EXPECT AT LEAST PATCHY FOG
AGAIN SATURDAY MORNING...BUT THIS WILL AGAIN BE TRICKY GIVEN THE
POTENTIAL FOR LOW CLOUDS.
SUNDAY STILL LOOKS HOT WITH HIGHS NEAR 90. ALSO STILL EXPECT IT TO
BE DRY PER GFS FORECAST SOUNDINGS...BUT AS NOTED IN THE PREVIOUS
DISCUSSION...LAKE BREEZE SHOWERS OR STORMS ARE NOT OUT OF THE
QUESTION AND THIS WILL HAVE TO BE WATCHED.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 323 PM EDT FRI SEP 4 2015
WE WILL SEE A BIG PATTERN CHANGE IN THE EXTENDED AS UPPER RIDGING AT
THE BEGINNING OF THE PERIOD IS REPLACED BY UPPER TROUGHING BY THE
END. IN BETWEEN WE ARE DEALING WITH A SLOW MOVING FRONT THAT SHOULD
BRING PERIODS OF RAIN...POSSIBLY HEAVY...FROM LATE MONDAY INTO EARLY
WEDNESDAY.
FORECAST UNCERTAINTY IS NOT SO MUCH WITH THE TIMING OF THAT INITIAL
FRONT BUT WITH THE HANDLING OF A SECONDARY FRONT THAT FOLLOWS AS THE
UPPER TROUGH DEEPENS. THE SPLIT BETWEEN THE SOLUTIONS VARIES FROM A
MUCH QUICKER GFS SOLUTION THAT BRINGS IT IN WEDNESDAY NIGHT AND
THURSDAY TO THE EURO WHICH HOLDS IF OFF UNTIL FRIDAY. DECIDED TO GO
TOWARDS THE LATER SOLUTION...SO KEPT THURSDAY DRY FOR NOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 142 AM EDT SAT SEP 5 2015
AREAS OF FOG WILL LIKELY BE IN AND OUT OF THE TAF SITES THROUGH
12Z OR 13Z. ABRUPT CHANGES IN VIS/CIG CAN BE EXPECTED AS THE FOG
DEVELOPS MAINLY NORTH OF THE AZO/BTL TERMINALS WHERE MORE CLEARING
HAS OCCURRED. VCTS THREAT EXISTS THIS MORNING MAINLY FOR AZO/BTL
PER HIGH RES MODEL GUIDANCE AND RADAR COLLABORATION. DAYTIME POP-
UP STORMS ARE POSSIBLE JUST ABOUT ANYWHERE TODAY WITH THE THREAT
ENDING CLOSE TO DARK.
&&
.MARINE...
ISSUED AT 323 PM EDT FRI SEP 4 2015
WINDS AND WAVES EXPECTED TO STAY LOW THROUGH SATURDAY NIGHT WITH A
SLIGHT UPTICK SUNDAY AHEAD OF AN APPROACHING COLD FRONT. LABOR DAY
COULD FEATURE WAVES OF 3 OR MORE FEET NORTH OF MUSKEGON AS WINDS
FROM THE SOUTH PERSIST AND CONTINUE TO INCREASE.
&&
.HYDROLOGY...
ISSUED AT 1054 AM EDT FRI SEP 4 2015
NO CONCERNS EXIST IN THE NEAR TERM. QUESTIONS ARISE GOING INTO NEXT
WEEK AS A BOUNDARY DRAPES ITSELF SOMEWHERE THROUGH OR NEAR THE GREAT
LAKES REGION.
AREA RIVERS HAVE RESPONDED PRETTY WELL TO YESTERDAYS RAINFALL.
LOCALIZED TOTALS OF MORE THAN TWO INCHES RESULTED IN DECENT UPWARD
TRENDS AT A FEW FORECAST POINTS. MOST NOTABLE IS SYCAMORE CREEK AT
HOLT...WHICH HAS LEVELED OFF ABOUT A FOOT BELOW ADVISORY CRITERIA.
PROVIDED THAT ADDITIONAL RAINFALL IS LIMITED...HOLT SHOULD CONTINUE
ITS DOWNWARD TREND. OTHER SITES HAVE ALSO LEVELED OFF AND RESPONSES
HAVE BEEN MINOR.
RAINFALL THROUGH THE WEEKEND IS EXPECTED TO BE SCATTERED WITH
LOCALIZED HEAVY RAIN POSSIBLE IN OR AROUND THUNDERSTORMS. CONDITIONS
ARE NOT FAVORABLE FOR WIDESPREAD HEAVY RAIN. A PATTERN CHANGE WILL
TAKE PLACE NEXT WEEK AND ITS ASSOCIATED BOUNDARY LOOKS TO BE MOVING
SLOWLY. DIFFERENCES IN LONG RANGE MODELS PUT A CAP ON ANY HIGH
CONFIDENCE. HOWEVER...PWATS ARE 1.5-2.0 INCHES AND THE SLOW
PROGRESSION OF THE BOUNDARY COULD RESULT IN PRETTY DECENT RAINFALL
TOTALS MONDAY THROUGH WEDNESDAY. THE SETUP MAY SUGGEST MORE THAN AN
INCH...WITH AREAS EXCEEDING A COUPLE OF INCHES IF STORMS ARE SLOW
MOVERS. THIS WILL LIKELY BE THE FOCUS HYDRO-WISE OVER THE NEXT
FEW DAYS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...DUKE
SYNOPSIS...TJT
SHORT TERM...TJT
LONG TERM...OSTUNO
AVIATION...HOVING
HYDROLOGY...JAM
MARINE...TJT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
117 AM EDT SAT SEP 5 2015
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 318 PM EDT FRI SEP 4 2015
AN UPPER RIDGE IS STRETCHING FROM A HIGH OVER TX TO WRN UPPER
MI...WRAPPING INTO WRN QUEBEC AROUND A WEAK UPPER DISTURBANCE OVER
LOWER MI. THIS HAS RESULTED IN CLEAR SKIES OVER MOST OF THE
CWA...WHILE SERN SECTIONS HAVE SOME CLOUD COVER. SOME CU IS BREAKING
OUT OVER ERN AND SCENTRAL UPPER MI...AS LOW LEVEL MOISTURE MOVES IS
AHEAD OF THE SLOWLY NORTHWARD MEANDERING DISTURBANCE. UP TO 500J/KG
OF CAPE IS BEING ANALYZED BY THE RAP OVER ERN UPPER MI...WHERE MANY
HIGH-RES MODELS SHOW SOME ISOLATED SHOWERS AND THUNDERSTORMS
BREAKING OUT OVER THE NEXT FEW HOURS. THESE SHOWERS AND
THUNDERSTORMS DIE OFF TONIGHT...BUT WE COULD SEE SOME ADDITIONAL
SHOWERS OVER THAT DIRECTION AS THE DISTURBANCE MOVES OVER. SHOULD
SEE FOG TONIGHT OVER MAINLY CENTRAL AND ERN UPPER MI AS THE LOW
LEVEL MOISTURE CONTINUES TO MOVE IN FROM THE SE.
SAT LOOKS WARMER AS SW FLOW INCREASES AND 850MB TEMPS INCREASE FROM
AROUND 15C TODAY TO 18-21C BY 00Z SUN. EXPECT HIGHS IN THE 70S NEAR
LAKE MICHIGAN...BUT IN THE 80S ELSEWHERE...AND EVEN 90 IN BARAGA. A
WEAK SHORTWAVE MOVING W OF THE AREA LATE TONIGHT INTO SAT MORNING
MAY LEAD TO SOME ISOLATED SHOWERS AND THUNDERSTORMS OVER WRN UPPER
MI. ANOTHER SHORTWAVE MOVES W OF THE AREA SAT
AFTERNOON/EVENING...WHICH MAY LEAD TO SHOWERS AND THUNDERSTORMS OVER
WRN UPPER MI. THE HIGH-RES WRF ARW AND NMM ALONG WITH THE GFS HAVE
THE MOST PRECIP...BUT THE GFS IS VERY MUCH AN OUTLIER AND THE WRFS
ARE MORE REALISTIC. OTHER MODELS ARE DRY FOR THE MOST PART. AS
ALWAYS IN THESE SITUATIONS...CONVECTIVE DEVELOPMENT IS
UNCERTAIN...BUT IT DOES APPEAR THAT ISOLATED TO SCATTERED PRECIP IS
MORE LIKELY. IF AFTERNOON CONVECTION DOES FORM...SOME OF THE STORMS
OVER FAR WRN UPPER MI COULD BE STRONG TO POSSIBLY SEVERE AS MUCAPES
WILL BE 1000-2000J/KG AND 0-6KM BULK SHEAR AROUND 20KTS. THINK
SEVERE CHANCES ARE LOW...BUT IT CAN NOT BE RULED OUT.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 500 PM EDT FRI SEP 4 2015
MODELS SUGGEST THAT WITH A GRADUAL PATTERN PROGRESSION...THE
MID/UPPER LEVEL RIDGE DOMINATING THE CNTRL CONUS WILL TRANSITION TO
A MORE ZONAL PATTERN EARLY NEXT WEEK AND A TROUGH OVER THE CNTRL
CONUS BY THE END OF THE WEEK. SO...ABOVE NORMAL TEMPERATURES WILL
GIVE WAY TO MORE SEASONAL CONDITIONS BY TUESDAY AND BELOW NORMAL
TEMPS BY WED-FRI WITH MORE FALL-LIKE WEATHER.
SAT NIGHT...WITH SW MID/UPPER LEVEL FLOW FROM THE PLAINS TO WRN LAKE
SUPERIOR...THE POTENTIAL WILL REMAIN FOR WEAK SHORTWAVES TO LIFT
INTO THE AREA THAT COULD TRIGGER SCT SHRA/TSRA. LOWER END CHANCE
POPS FOR SHRA/TSRA CHANCES WILL BE CONFINED TO WRN UPPER MI.
SUNDAY THROUGH SUNDAY NIGHT...A VIGOROUS SHORTWAVE TROUGH OVER SW
SASK LIFTING INTO MANITOBA WILL HELP FLATTEN THE RIDGE. A SFC TROUGH
WILL DEVELOP INTO NRN ONTARIO WITH A COLD FRONT THROUGH THE UPPER MS
VALLEY LATE SUNDAY MOVING THROUGH UPPER MI BY LATE SUN NIGHT INTO
EARLY MON. ALTHOUGH SOME SHRA/TSRA MAY BRUSH THE WRN CWA...EXPECT
CAPPING WILL BE STRONG ENOUGH DURING THE PEAK HEATING AND HIGHER
INSTABILITY TO MINIMIZE SHRA/TSRA CHANCES. WITH 850 MB TEMPS NEAR
20C...TEMPS WILL CLIMB WELL ABOVE NORMAL WITH HIGHS IN THE UPPER 80S
TO POSSIBLY 90 IN SSW DOWNSLOPE FLOW LOCATIONS.
AS THE FRONT APPROACHES SUNDAY NIGHT...THE COMBINATION OF HEIGHT
FALLS...LOW LEVEL CONV NEAR THE FRONT AND THE LIKELIHOOD OF WEAKER
SHORTWAVES APPROACHING THE AREA IN SW FLOW FROM THE PLAINS WILL
SUPPORT LIKELY POPS. WITH MUCAPE VALUES TO AT LEAST 1K J/KG AND 0-
6KM SHEAR OF 30-35 KNOTS...SOME STRONGER STORMS WILL BE POSSIBLE.
HOWEVER...WITH HIGH FREEZING LEVELS...PWAT VALUES TO AROUND 2.0
INCHES...AND POTENTIAL FOR BACKBUILDING CONVECTION FROM 45 KT SW
INFLOW...PER CORFIDI VECTORS...HEAVY RAIN MAY BE THE GREATER HAZARD.
MON...SOME SHRA AND POSSIBLY TSRA MAY LINGER INTO EARLY MONDAY OVER
THE ERN CWA...PER SLOWER ECMWF. OTHERWISE...DRIER AIR AND CLEARING
WILL MOVE IN WITH WRLY LOW LEVEL FLOW.
TUE-FRI...PCPN CHANCES ARE MORE UNCERTAIN GIVEN LARGER MODEL
DIFFERENCES WITH THE STRENGTH AND POSITION OF SHORTWAVES AND THE
INTERACTION WITH THE FRONT TO THE SOUTH OF THE REGION. FOR
NOW...ONLY LOWER END SHRA CHANCES WERE INCLUDED...PER MDLS
CONSENSUS. WITH THE MID LEVEL TROUGH DEVELOPING OVER THE
REGION...ENOUGH COLD AIR MAY MOVE IN...PER ECMWF WITH 850 MB
TEMPS DOWN TO 3C...TO SUPPORT LAKE ENHANCED RAIN BY FRI.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 116 AM EDT SAT SEP 5 2015
AN INCREASE IN MOISTURE FROM THE SE SHOULD RESULT IN FOG AND SOME
STRATUS DEVELOPMENT OVERNIGHT...MAINLY AT KSAW WHICH IS CLOSER TO
THE ARRIVING MOISTURE POOL AND DUE TO BETTER UPSLOPING. AT
KSAW...EXPECT IFR CONDITIONS WITH THE POTENTIAL OF A PERIOD OF LIFR
CONDITIONS AROUND SUNRISE. A PERIOD OF MVFR VIS IS EXPECTED AT KCMX
AROUND SUNRISE...BUT KIWD WILL PROBABLY STAY VFR WITH A DOWNSLOPE
WIND THRU THE NIGHT. FOG/STRATUS WILL BURN OFF IN THE
MORNING...RESULTING IN VFR CONDITIONS PREVAILING FROM MID MORNING
INTO THE EVENING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 318 PM EDT FRI SEP 4 2015
EAST TO NORTHEAST WINDS OF 10-15KT WILL CONTINUE UNTIL THE NEXT
CHANCE FOR WINDS GREATER THAN 20KT COMES ON MONDAY BEHIND A COLD
FRONT. FOG WILL CONTINUE TO BE PATCHY ACROSS THE LAKE UNTIL THE COLD
FRONT MOVES THROUGH.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...TITUS
LONG TERM...JLB
AVIATION...ROLFSON
MARINE...TITUS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1030 PM CDT SUN SEP 6 2015
.UPDATE...FOR 06Z AVIATION DISCUSSION BELOW
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 253 PM CDT SUN SEP 6 2015
THE SEVERE THREAT CONTINUES...BUT SEEMS MORE CONDITIONAL GIVEN THE
BROAD SURFACE TROUGH SEPARATING THE SOUTHERLY WINDS NEAR THE TWIN
CITIES...WITH THE NORTHWESTERLY WINDS BEHIND THE APPROACHING COLD
FRONT. AS A RESULT DO NOT HAVE A FOCUSED AREA OF LOW LEVEL
CONVERGENCE OVER THE FORECAST AREA...WHICH LEADS TO A LARGE AREA OF
SHALLOW CONVECTION MANIFESTED BY THE SCATTERED SHOWERS AND
THUNDERSTORMS THAT CONTINUE TO DEVELOP ALONG THE SOUTHERN END OF THE
SURFACE TROUGH.
A SUBTLE SHORTWAVE EMBEDDED IN SOUTHWEST FLOW WILL ENHANCE THE LIFT
ACROSS SOUTHEAST MN / WESTERN WILL THIS AFTERNOON...AND AS OF 19Z
SEE COOLING CLOUD TOPS IN THIS REGION. HOWEVER DEEP LAYER SHEAR IS
ONLY AROUND 30 TO 35KTS...SO IT IS DOUBTFUL THAT ANY SEVERE WEATHER
WILL COME FROM THIS AREA OF SHOWERS AND THUNDERSTORMS. THE BETTER
DYNAMICS ARE ACROSS NORTHWEST MN...AND ONE STORM IN PARTICULAR WAS
ABLE TO REALIZE THE INSTABILITY AS WELL. THIS STORM IS LIFTING
NORTHEAST AND WILL NOT AFFECT THE CWA...BUT HIRES MODELS TRY TO
EXTEND CONVECTION SOUTHWARD ALONG THE COLD FRONT AND THAT WILL BE
OUR WINDOW FOR STRONG TO SEVERE STORMS LATER THIS AFTERNOON/EVENING.
MID 70 DEWPOINTS HAVE ALLOWED SBCAPE TO INCREASE ABOVE 3000 J/KG IN
WESTERN MN...AND 500MB WINDS ARE NOW NEAR 50KTS...SO DEEP LAYER
SHEAR SUPPORTS ORGANIZED CONVECTION IN THIS REGION. HOWEVER...THE
FACT THAT THIS IS POST FRONTAL (SURFACE WINDS ARE NORTHWESTERLY)
RAISES SOME SKEPTICISM AS TO IF SEVERE WEATHER WILL INDEED OCCUR
LATER TODAY.
LASTLY...A NARROW BAND OF WEAK ECHOES RESIDES WELL BEHIND THE
FRONT...AND HIRES MODELS...IN PARTICULAR THE HRRR AND HRRR-DEV
INDICATE FESTERING CONVECTION ALONG THIS LINE SO HAVE HUNG ONTO THE
POPS A BIT LONGER BEHIND THE SURFACE COLD FRONT. TEMPERATURES WILL
COOL INTO THE 50S ACROSS WESTERN MN..AND 60S IN WESTERN WI. MONDAY
WILL BE COOLER AND DRIER...BUT POST FRONTAL WINDS ARE NOT AS STRONG
AS ONE WOULD EXPECT. THIS IS BECAUSE THE UPPER LEVEL WAVE BECOME
OCCLUDED AND SLOWS DOWN...THUS NOT DRIVING THE BOUNDARY THROUGH THE
REGION.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 253 PM CDT SUN SEP 6 2015
COLD FRONT WILL STALL OVER IOWA MONDAY AND RETURN SLIGHTLY BACK TO
THE NORTH AS A WARM FRONT MONDAY NIGHT WITH THE EJECTION OF A MID
LEVEL DISTURBANCE FROM THE SOUTHWEST. 850 MB JET WILL STRENGTHEN
MONDAY NIGHT...BUT WILL BE VEERED TO THE NORTHEAST MORE TOWARD
IOWA AND SOUTHWESTERN WI. NONETHELESS...WILL LIKELY SEE SOME SHOWER
AND THUNDERSTORM DEVELOPMENT OVER NORTHWESTERN IOWA THAT SHOULD
LIFT NORTHEAST ACROSS SRN MN/WRN WI LATE MONDAY NIGHT. MODELS ARE
IN PRETTY GOOD AGREEMENT...ALTHOUGH THE NAM IS A BIT FURTHER NORTH
AS USUAL. INCREASED POPS INTO THE LIKELY RANGE ACROSS THE SOUTH
WITH A SHARP GRADIENT TO THE NORTH.
NEXT DISTURBANCE TO WATCH WILL ARRIVE WEDNESDAY NIGHT-THURSDAY.
THERE WON/T BE MUCH TIME FOR DEEP MOISTURE TO RETURN AHEAD OF THIS
FEATURE...SO THINK THE THUNDER THREAT IS LOW. SOME SHOWERS ARE
ANTICIPATED AHEAD OF THE FRONT BUT AMOUNTS WON/T BE NEWSWORTHY.
A BLAST OF AUTUMN WILL ACCOMPANY THE FOLLOWING 1022 MB HIGH FOR
LATE WEEK. HIGHS IN THE 60S AND LOWS IN THE 40S WILL MARK A
SIGNIFICANT CHANGE FROM EARLIER IN THE WEEK.
WARMER AIR WILL BEGIN RETURNING FOR LATE IN THE PERIOD AS RIDGING
BUILDS BACK INTO THE NORTHERN PLAINS. TEMPS IN THE MID/UPPER 70S
SEEM PROBABLE WHICH WILL BE SLIGHTLY ABOVE NORMAL VALUES OF LOW/MID
70S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1030 PM CDT SUN SEP 6 2015
IN THE WAKE OF THE SHOWERS AND THUNDERSTORMS...CONCERNS ARE FEW
THIS PERIOD. PRIMARY IMPACT TO AVIATION MAY BE FOG DEVELOPMENT
DURING THE OVERNIGHT HOURS...PRIMARILY AT WI SITES /KEAU AND
KRNH/...ALTHOUGH LIGHT BR COULD DEVELOP AS FAR WEST AS KMSP.
OTHERWISE...HIGH CLOUDS INCREASE FROM THE WEST/SOUTH ON MONDAY AS
THE NEXT SYSTEM APPROACHES. COULD SEE ASSOCIATED SHRA/TS ARRIVE AS
EARLY AS 03Z TUE IN SOUTHERN MN /KRWF/. NORTHWEST WINDS IN THE
WAKE OF THE COLD FRONT WILL GRADUALLY SHIFT TO THE NORTHEAST BY
EARLY MONDAY MORNING...AND THEN BECOME EAST/SOUTHEAST MONDAY P.M.
KMSP...
LIGHT BR WITH MINOR VSBY REDUCTIONS APPEARS POSSIBLE AROUND
DAYBREAK...OTHERWISE VFR CONDITIONS ARE EXPECTED THRU PERIOD.
/OUTLOOK FOR KMSP/
TUE...VFR WITH MVFR/TSRA POSSIBLE. WIND NNW AT 10KT.
WED...VFR. WIND S AT 5KT.
THU...VFR. WITH -SHRA EARLY. WIND SW BCMG NW AT 15G20KT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JRB
LONG TERM...BORGHOFF
AVIATION...LS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
659 PM CDT SUN SEP 6 2015
.UPDATE...FOR 00Z AVIATION DISCUSSION BELOW
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 253 PM CDT SUN SEP 6 2015
THE SEVERE THREAT CONTINUES...BUT SEEMS MORE CONDITIONAL GIVEN THE
BROAD SURFACE TROUGH SEPARATING THE SOUTHERLY WINDS NEAR THE TWIN
CITIES...WITH THE NORTHWESTERLY WINDS BEHIND THE APPROACHING COLD
FRONT. AS A RESULT DO NOT HAVE A FOCUSED AREA OF LOW LEVEL
CONVERGENCE OVER THE FORECAST AREA...WHICH LEADS TO A LARGE AREA OF
SHALLOW CONVECTION MANIFESTED BY THE SCATTERED SHOWERS AND
THUNDERSTORMS THAT CONTINUE TO DEVELOP ALONG THE SOUTHERN END OF THE
SURFACE TROUGH.
A SUBTLE SHORTWAVE EMBEDDED IN SOUTHWEST FLOW WILL ENHANCE THE LIFT
ACROSS SOUTHEAST MN / WESTERN WILL THIS AFTERNOON...AND AS OF 19Z
SEE COOLING CLOUD TOPS IN THIS REGION. HOWEVER DEEP LAYER SHEAR IS
ONLY AROUND 30 TO 35KTS...SO IT IS DOUBTFUL THAT ANY SEVERE WEATHER
WILL COME FROM THIS AREA OF SHOWERS AND THUNDERSTORMS. THE BETTER
DYNAMICS ARE ACROSS NORTHWEST MN...AND ONE STORM IN PARTICULAR WAS
ABLE TO REALIZE THE INSTABILITY AS WELL. THIS STORM IS LIFTING
NORTHEAST AND WILL NOT AFFECT THE CWA...BUT HIRES MODELS TRY TO
EXTEND CONVECTION SOUTHWARD ALONG THE COLD FRONT AND THAT WILL BE
OUR WINDOW FOR STRONG TO SEVERE STORMS LATER THIS AFTERNOON/EVENING.
MID 70 DEWPOINTS HAVE ALLOWED SBCAPE TO INCREASE ABOVE 3000 J/KG IN
WESTERN MN...AND 500MB WINDS ARE NOW NEAR 50KTS...SO DEEP LAYER
SHEAR SUPPORTS ORGANIZED CONVECTION IN THIS REGION. HOWEVER...THE
FACT THAT THIS IS POST FRONTAL (SURFACE WINDS ARE NORTHWESTERLY)
RAISES SOME SKEPTICISM AS TO IF SEVERE WEATHER WILL INDEED OCCUR
LATER TODAY.
LASTLY...A NARROW BAND OF WEAK ECHOES RESIDES WELL BEHIND THE
FRONT...AND HIRES MODELS...IN PARTICULAR THE HRRR AND HRRR-DEV
INDICATE FESTERING CONVECTION ALONG THIS LINE SO HAVE HUNG ONTO THE
POPS A BIT LONGER BEHIND THE SURFACE COLD FRONT. TEMPERATURES WILL
COOL INTO THE 50S ACROSS WESTERN MN..AND 60S IN WESTERN WI. MONDAY
WILL BE COOLER AND DRIER...BUT POST FRONTAL WINDS ARE NOT AS STRONG
AS ONE WOULD EXPECT. THIS IS BECAUSE THE UPPER LEVEL WAVE BECOME
OCCLUDED AND SLOWS DOWN...THUS NOT DRIVING THE BOUNDARY THROUGH THE
REGION.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 253 PM CDT SUN SEP 6 2015
COLD FRONT WILL STALL OVER IOWA MONDAY AND RETURN SLIGHTLY BACK TO
THE NORTH AS A WARM FRONT MONDAY NIGHT WITH THE EJECTION OF A MID
LEVEL DISTURBANCE FROM THE SOUTHWEST. 850 MB JET WILL STRENGTHEN
MONDAY NIGHT...BUT WILL BE VEERED TO THE NORTHEAST MORE TOWARD
IOWA AND SOUTHWESTERN WI. NONETHELESS...WILL LIKELY SEE SOME SHOWER
AND THUNDERSTORM DEVELOPMENT OVER NORTHWESTERN IOWA THAT SHOULD
LIFT NORTHEAST ACROSS SRN MN/WRN WI LATE MONDAY NIGHT. MODELS ARE
IN PRETTY GOOD AGREEMENT...ALTHOUGH THE NAM IS A BIT FURTHER NORTH
AS USUAL. INCREASED POPS INTO THE LIKELY RANGE ACROSS THE SOUTH
WITH A SHARP GRADIENT TO THE NORTH.
NEXT DISTURBANCE TO WATCH WILL ARRIVE WEDNESDAY NIGHT-THURSDAY.
THERE WON/T BE MUCH TIME FOR DEEP MOISTURE TO RETURN AHEAD OF THIS
FEATURE...SO THINK THE THUNDER THREAT IS LOW. SOME SHOWERS ARE
ANTICIPATED AHEAD OF THE FRONT BUT AMOUNTS WON/T BE NEWSWORTHY.
A BLAST OF AUTUMN WILL ACCOMPANY THE FOLLOWING 1022 MB HIGH FOR
LATE WEEK. HIGHS IN THE 60S AND LOWS IN THE 40S WILL MARK A
SIGNIFICANT CHANGE FROM EARLIER IN THE WEEK.
WARMER AIR WILL BEGIN RETURNING FOR LATE IN THE PERIOD AS RIDGING
BUILDS BACK INTO THE NORTHERN PLAINS. TEMPS IN THE MID/UPPER 70S
SEEM PROBABLE WHICH WILL BE SLIGHTLY ABOVE NORMAL VALUES OF LOW/MID
70S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 659 PM CDT SUN SEP 6 2015
LINE OF STORMS MOVING ACROSS CENTRAL MN WILL GRADUALLY WEAKEN AS
IT MOVES EASTWARD INTO MORE STABLE AIR. IN THE MEANTIME...KSTC
WILL BE AFFECTED AT THE START OF THE PERIOD...AND EVENTUALLY KMSP
/AROUND 03Z/ AND KRNH /04Z/. MVFR CIGS AND MVFR/IFR VSBYS ARE
EXPECTED WITH THE LINE OF STORMS...ALONG WITH STRONGER WIND
GUSTS...FREQUENT LIGHTNING...AND A PERIOD OF HEAVY RAINFALL. IN
THE WAKE OF THE LINE OF STORMS AS THE LOW/MID CLOUDS SCATTER OUT...FOG
APPEARS POSSIBLE AT CENTRAL/EASTERN SITES WHERE THE POST-FRONTAL
NORTHWEST WINDS WILL NOT HAVE KICKED IN YET...PRIMARILY
KMSP/KRNH/KEAU. VFR CONDITIONS ARE THEN EXPECTED AFTER 15Z...WITH
WINDS SHIFTING NORTH THEN EAST/NORTHEAST FOR MONDAY AFTERNOON.
KMSP...
LINE OF STORMS EXPECTED TO IMPACT KMSP BETWEEN 0245Z AND 04Z. MVFR
CIGS AND IFR VSBYS ARE POSSIBLE. VARIABLE WINDS WITH GUSTS TO
AROUND 40 KTS CANNOT BE RULED OUT AS THE LINE PASSES. BR
DEVELOPMENT IS POSSIBLE DURING THE EARLY MORNING HOURS WITH
MVFR/IFR VSBYS.
/OUTLOOK FOR KMSP/
TUE...VFR WITH MVFR/TSRA POSSIBLE. WIND NNW AT 10KT.
WED...VFR. WIND S AT 05KT.
THU...VFR. WITH -SHRA EARLY. WIND SW BCMG NW AT 15G20KT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JRB
LONG TERM...BORGHOFF
AVIATION...LS
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
358 PM CDT SAT SEP 5 2015
.DISCUSSION...
Issued at 358 PM CDT SAT SEP 5 2015
Very warm and muggy conditions across the area this afternoon with
gusty winds in the 20 to 30 mph range. The resultant heat indices
have reached into the middle to upper 90s this afternoon. Satellite
imagery has indicated a well formed CU field across the entire area,
likely in response to the surface temperatures approaching or even
reaching convective temperature. A few storms have formed in central
Missouri across the far southeastern EAX zones, but this activity is
anticipated to be isolated in nature. There is no real surface
boundary, nor much in the way of upper level support as mid level
pressure heights are actually rising a bit through the afternoon.
Have introduced some low end SChc PoPs for the southeastern zones
for this concern. Otherwise, RAP forecast soundings indicate that
there is still a bit of a CAP over the area, so without any of the
aforementioned support for ascent it`s pretty unlikely that
convection will get going this afternoon. Expect a repeat on Sunday
of Saturday`s conditions with another day reaching the lower to
middle 90s, with moist conditions allowing heat indices to reach the
upper 90s to perhaps 100 degrees.
Large scale pattern change is in store for the late part of Sunday
into next week. The large ridge will ultimately break down as a
large trough moves into the northern plains. Ultimately a surface
boundary will slide into the area and be accompanied by decreasing
mid level pressure heights, allowing for convection to pick up first
across southeast Nebraska and southwest Iowa on Sunday night, then
eventually forming and moving into northwest Missouri. Thereafter
for the remainder of the Sunday through Wednesday time frame
increases mid level flow aloft as well as the boundary will bring
off and on chances for rain through the first half of next week. The
formation of 1 or more MCS`s look to be likely, mainly north of I-70
for the Sunday night through Tuesday night period, with perhaps a
couple rounds of very heavy rain across far northern Missouri into
southern Iowa. Chances for rain will generally slide south with the
boundary as the week progresses. Instability and shear don`t look to
be astronomically high, however there will likely be enough of both
parameters to warrant at least a concern for some marginally
organized storm formations, that could bring some wind along with
the heavy rain threat. Perhaps the most concerning aspect of this
event will be the potential for heavy rain. PWAT values across
northern Missouri could approach or even surpass 2 inches, which is
incredibly high for the early September time period. There is
certainly some concern for some flooding and flash flooding as a
result of repeated rounds of heavy rain through mid week. By
Wednesday evening, the boundary looks like it`ll be south of the
forecast area, with a more continental influenced air mass. The
result will be a drying out period and very comfortable temperatures
for the late part of the upcoming week, into the next weekend.
Expect Highs in the 80s for Thursday, then all the way down into the
upper 60s and lower 70s for late in the week into the Sat/Sun time
period.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon)
Issued at 106 PM CDT SAT SEP 5 2015
VFR expected for next 24 hours with winds diminishing over night
then picking back up on Sunday.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
DISCUSSION...Leighton
AVIATION...Leighton
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
855 PM MDT SUN SEP 6 2015
.DISCUSSION...
UPDATE FORTHCOMING. MODELS, INCLUDING HRRR AND RAP13,
ALL BEING SOME LIGHT PRECIPITATION OFF THE ROCKY MOUNTAIN FRONT AND
OUT OVER THE PLAINS AFTER 06Z AS WEAK SHORT WAVE ENERGY MOVES
THROUGH. HAVE ADDED LOW POPS FOR AFOREMENTIONED AREA FOR THIS
REASON. REMAINDER OF FORECAST LOOKS GOOD AS DO OVERNIGHT LOWS.
&&
.AVIATION...
UPDATED 1740Z.
WESTERLY FLOW ALOFT WILL CONTINUE TO BRING MID AND
HIGH CLOUDS ACROSS THE AREA. GUSTY WESTERLY SURFACE WINDS WILL
DECREASE AFTER 02Z BUT WINDS WILL INCREASE AGAIN AFTER 18Z. VFR
CONDITIONS PREVAIL.
&&
.PREV DISCUSSION...ISSUED 241 PM MDT SUN SEP 6 2015
TONIGHT THROUGH TUESDAY...GUSTY WESTERLY WINDS AFFECTING THE
FORECAST AREA THIS AFTERNOON WILL DIMINISH DURING THE EARLY TO MID
EVENING HOURS. WEST TO NORTHWEST CYCLONICALLY-CURVED FLOW ALOFT
WILL PREVAIL FOR MONDAY AND TUESDAY WITH AFTERNOON HIGH
TEMPERATURES REMAINING BELOW SEASONAL AVERAGES. SEVERAL SHORTWAVES
MOVING THROUGH THE FLOW ALOFT WILL BRING SCATTERED SHOWERS TO THE
MOUNTAINS OF THE CONTINENTAL DIVIDE AND GLACIER PARK, BUT ONLY
ISOLATED LIGHT RAIN SHOWERS ARE EXPECTED IN THE PLAINS AND
VALLEYS. WINDS REMAIN WESTERLY AND BREEZY BUT ARE NOT EXPECTED TO
BE AS STRONG AS THOSE OF TODAY. MPJ
TUESDAY NIGHT THROUGH SUNDAY...LITTLE IF ANY SIGNIFICANT WEATHER
EXPECTED DURING THIS PERIOD. ONLY WEATHER SYSTEM OF NOTE IS A
QUICK- MOVING SHORTWAVE TROF THAT WILL PRODUCE SOME SCATTERED
LIGHT RAIN SHOWERS THROUGH CENTRAL MT THROUGH TUES NIGHT. ALSO,
RESIDUAL MOISTURE FROM THIS SYSTEM MAY COMBINE WITH NORTHWEST FLOW
ALOFT TO GENERATE A FEW SHOWERS AND A THUNDERSTORM OR TWO OVER THE
LITTLE BELT AND SNOWY MTNS ON WED AFTN/EVE WHILE REST OF REGION
REMAINS DRY. FROM LATE WED ONWARD, HIGH PRESSURE RIDGING WILL
SLOWLY BUILD INTO THE NORTHERN ROCKIES, MAINTAINING THE DRY
CONDITIONS THROUGH AT LEAST SATURDAY. LATEST FORECAST MODEL RUNS
SHOW THE NORTHERN PORTION OF THE RIDGE WEAKENING ON SUNDAY IN
RESPONSE TO AN UPPER- LEVEL TROF MOVING THROUGH WESTERN CANADA.
HOWEVER, ONLY LIMITED MOISTURE MAKES IT SOUTH OF THE US/CAN
BORDER, PERHAPS ENOUGH TO DEVELOP A FEW SHOWERS ALONG THE ROCKY
MTN FRONT, BUT DOWNSLOPE FLOW SHOULD KEEP PRECIPITATION FROM
FORMING OVER THE PLAINS. AS THE RIDGE MOVES INTO OUR REGION, WE`LL
SEE A GRADUALLY WARMING TREND WITH LOW 70S ON THURS INCREASING TO
THE LOW 80S FOR SAT. 12Z FORECAST MODELS INDICATE THE POTENTIAL
FOR A DISTURBANCE WITH AN ASSOCIATED COLD FRONT TO MOVE THROUGH
THE FORECAST AREA ON SUNDAY, BUT THERE IS SOME DISCREPANCY WITH
REGARDS TO STRENGTH. HAVE THEREFORE ADDED MENTION OF SHOWERS AND
HAVE COOLED SUNDAY`S HIGHS AROUND 5 DEGREES TO ACCOUNT FOR THIS.
WARANAUSKAS/COULSTON
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 43 62 42 67 / 10 10 10 10
CTB 40 60 42 64 / 10 20 10 10
HLN 42 64 40 68 / 10 10 20 0
BZN 37 63 36 70 / 0 0 20 0
WEY 23 59 23 62 / 0 0 10 0
DLN 35 62 35 69 / 0 0 10 0
HVR 39 62 41 67 / 10 10 10 10
LWT 41 60 39 68 / 10 10 10 0
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
WEATHER.GOV/GREATFALLS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
422 PM MDT SAT SEP 5 2015
.UPDATE...
SFC LOW DEVELOPING IN NORTHERN WY IS ALLOWING FOR COOLER AIR TO
SURGE INTO OUR WESTERN ZONES...WITH A TEMP DOWN TO 48 AT JUDITH
GAP AND 63 AT BILLINGS. THIS HAS ELIMINATED ANY RISK OF SEVERE
STORMS FROM ROUNDUP-BILLINGS WESTWARD. MOST RECENT HRRR RUNS
SUGGEST STRONG STORMS DEVELOPING IN SOUTHERN BIG HORN COUNTY SOON
AND TRACKING ACROSS OUR SOUTHEAST THIS EVENING. THIS SEEMS TO BE A
REASONABLE SCENARIO AS WEAK COOL ADVECTION CONTINUES TO IMPACT
MORE NORTHERN LOCATIONS SUCH AS HYSHAM...FORSYTH AND MILES CITY...
WHERE LATEST MESOANALYSIS SHOWS QUITE A BIT OF CIN.
JKL
&&
.SHORT TERM...VALID FOR SUN AND MON...
CONDITIONS STILL FAVORABLE FOR A PERIOD OF SEVERE WX LATE THIS
AFTERNOON AND EVENING AS APPROACHING PACIFIC TROF INTERACTS WITH A
MOIST AND UNSTABLE AIRMASS WITH AMPLE SHEAR. GREATEST SEVERE
POTENTIAL IS FROM BILLINGS EASTWARD FROM ABOUT 4 PM THRU MIDNIGHT.
LATEST HIGH RES MODELS SUGGEST SOME SLIGHT DEVIATIONS IN THE
LOCATION OF THE SEVERE POTENTIAL. DEPARTING ENERGY IN THE DAKOTAS
AND STRATUS OVER NE MT HAS RESULTED IN A LIGHT N-NW WIND FROM
FORSYTH TO MILES CITY...A MODEST STABILIZING WIND AND MILES CITY
REMAINS AT 67 DEGREES W/ AN MVFR CIG AS OF 3PM. LATEST NSSL-WRF
ALSO SHOWS GREATEST UPDRAFT HELICITY ACROSS SOUTHEAST MT AND THIS
SEEMS REASONABLE GIVEN GREATEST OBSERVED PRESSURE FALLS AND SFC
LOW IN NORTHEAST WY...WHERE DRIER MIXED SW WINDS HAVE DEVELOPED.
HRRR HAS THUS BEEN TRENDING SLIGHTLY SOUTH WITH DEVELOPMENT OF A
FEW STRONGER CELLS OVER THE NEXT FEW HOURS AND THIS SEEMS
REASONABLE GIVEN WHAT WE HAVE SEEN TODAY. SO GREATEST THREAT MAY
NOT BE FROM HYSHAM-FORSYTH-MLS BUT RATHER CLOSER TO HARDIN-LAME
DEER-BROADUS-EKALAKA-BAKER. BILLINGS IS ON THE WESTERN EDGE OF THE
THREAT. IT IS POSSIBLE THAT THE JUNKY CONVECTION CURRENTLY COMING
OFF THE BEARTOOTH ABSAROKAS WILL MUDDLE UP OUR AIRMASS ENOUGH TO
KEEP THE BETTER SEVERE POTENTIAL EAST OF BILLINGS...WHICH IS ALSO
A RECENT TREND OF THE HRRR. OVERALL IT IS A SOMEWHAT COMPLICATED
PICTURE OUT THERE AND PEOPLE WHO ARE OUTDOORS SHOULD STAY ALERT OF
THE WX FROM NOW THRU MIDNIGHT.
FURTHER WEST...WE ARE SEEING DRIER MIXED WINDS AT LIVINGSTON.
WHEREAS THIS GREATLY REDUCES THE SVR RISK ALONG THE FOOTHILLS THIS
AREA WILL BE PRONE TO SEE STRONG WIND GUSTS WITH ANY WEAK CELLS.
THIS INCLUDES LIVINGSTON WHERE FLOW ALOFT IS PARALLEL TO THE
PARADISE VALLEY...IE A PRIME SET UP FOR A STRONG CONVECTIVELY
INDUCED GAP WIND AT LVM.
DRIER WEST WINDS WILL PUSH ACROSS THE CWA LATE TONIGHT AND PCPN
SHOULD EXIT OUR EAST BY 12Z. A MUCH DRIER AND COOLER-THAN-NORMAL
REGIME CAN BE EXPECTED MONDAY AND TUESDAY...WITH HIGH TEMPS
RANGING FROM THE MID 60S TO MID 70S AND FAIRLY CHILLY LOWS MOSTLY
IN THE UPPER 30S AND 40S. WEAK SHORTWAVE SUNDAY NIGHT WILL HAVE
VERY LITTLE MOISTURE TO WORK WITH SO WILL KEEP FORECAST DRY.
STRONGER ENERGY WILL HAVE A BETTER CHANCE OF PRODUCING SOME LIGHT
SHOWERS MONDAY NIGHT AND HAVE ADDED A LOW POP IN WEST AND CENTRAL
PARTS TO COVER THIS. THIS IS WELL AGREED UPON BY THE GFS...ECMWF
AND CANADIAN MODELS.
JKL
.LONG TERM...VALID FOR TUE...WED...THU...FRI...SAT...
MADE A FEW MINOR CHANGES THE EXTENDED FORECAST PERIOD...BUT
OVERALL THE STORY REMAINS THE SAME...WITH GENERALLY QUIET AND
MAINLY DRY WEATHER THROUGH NEXT WEEK.
TEMPS ARE LOOKING SLIGHTLY COOLER OVERALL THAN PREVIOUS MODELS
INDICATED...DUE TO A SUCCESSION OF SHORTWAVES BRINGING REINFORCING
SHOTS OF COOL AIR. MORNINGS LOWS IN THE 40S F MOST NIGHTS...AND
HIGHS BETWEEN 65 AND 75 F THROUGH THURSDAY. TEMPS CLIMB BACK TO
AROUND NORMAL OR EVEN SLIGHTLY ABOVE FOR FRIDAY AND SATURDAY.
AS MENTIONED...MAINLY DRY CONDITIONS WILL PREVAIL THROUGH THE
PERIOD...IN GENERALLY DRY AIRMASS...BUT DID ADD POPS FOR TUESDAY
MORNING...AND THROUGH THE DAY WEDNESDAY. A SHORTWAVE IS EXITING
THE REGION TUESDAY MORNING...AND A COUPLE MORE APPEAR TO CROSS THE
REGION WEDNESDAY MORNING AND EVENING. MODELS HAVE BEEN TRENDING
STRONGER AND WETTER WITH THESE WAVES OVER PAST COUPLE OF RUNS...SO
DID NOT FEEL COMFORTABLE LEAVING COMPLETELY DRY. AAG
&&
.AVIATION...
MVFR CIGS CONTINUE IN EXTREME EASTERN MONTANA...WITH IMPROVING
CIGS FROM KSHR TO KBIL AND WEST. A FEW SHOWERS ARE DEVELOPING
WEST OF KBIL...INCLUDING KLVM...AND ARE POSSIBLE THROUGH MID
AFTERNOON. STRONGER STORMS ARE EXPECTED TO BEGIN DEVELOPING BY 22Z
AND MOVE ACROSS SOUTH CENTRAL AND SOUTHEASTERN MT THROUGH THE
EVENING HOURS. MVFR TO IFR CONDITIONS WITH HEAVY RAIN...STRONG
WINDS...AND LARGE HAIL ARE POSSIBLE WITH THE STRONGEST STORMS.
FINALLY...AREA MOUNTAINS WILL BE FREQUENTLY OBSCURED THROUGH THIS
EVENING. AAG
&&
.PRELIMINARY POINT TEMP/POPS...
SUN MON TUE WED THU FRI SAT
-----------------------------------------------------------
BIL 048/073 044/071 045/074 048/070 046/071 046/078 051/080
60/N 00/B 22/W 22/T 21/B 11/U 11/U
LVM 043/069 035/068 039/072 043/071 042/073 044/079 046/080
30/N 01/B 22/W 22/T 21/U 11/U 10/U
HDN 048/073 042/072 042/075 047/072 045/072 045/079 049/082
80/N 00/B 22/W 22/T 21/B 11/U 11/U
MLS 052/072 044/071 045/074 049/070 044/069 045/076 049/080
80/N 00/B 12/W 22/T 21/B 10/U 00/U
4BQ 052/071 043/071 046/074 050/071 047/070 046/075 050/079
70/N 00/B 12/W 22/T 21/B 10/U 00/U
BHK 053/070 043/070 043/072 047/069 043/067 041/072 047/077
70/N 01/B 02/W 22/T 21/B 10/U 11/U
SHR 047/071 038/072 041/074 044/072 042/070 042/076 046/080
30/B 00/B 12/W 22/T 21/B 11/U 11/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
134 PM CDT SAT SEP 5 2015
.SYNOPSIS...
ISSUED AT 400 AM CDT SAT SEP 5 2015
WEAK EMBEDDED SHORT WAVE MOVING QUICKLY ACROSS THE CENTRAL
ROCKIES AND ONTO THE HIGH PLAINS IN SWRLY FLOW ALOFT WORKING IN
CONCERT WITH LLJ TO GENERATE SHRA AND ISOLD TSRA ACROSS PORTIONS
OF WRN NEB EARLY THIS MORNING. MEANWHILE UPPER TROUGH AND
ASSOCIATED LOW OVER THE PAC NW STARTING TO MOVE EWD WHILE HEIGHTS
RISE ACROSS THE PLAINS. THESE TWO THINGS CONTRIBUTING TO
TIGHTEN/INCREASE THE UPPER FLOW AHEAD OF THE LOW IN THE NW.
MOISTURE AND ASSOCIATED CONVECTIVE ACTIVITY FROM TROPICAL STORM
KEVIN MOVING ONSHORE ON THE BAJA PENINSULA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 400 AM CDT SAT SEP 5 2015
FORECAST ISSUES FOR EARLY THIS MORNING INVOLVES THE POTENTIAL FOR
ADDITIONAL CONVECTIVE DEVELOPMENT IN SRN/WRN NEB WHICH SEVERAL OF
THE CAMS SUGGEST WILL HAPPEN THROUGH THE MORNING. RADAR ECHOES
OVER THE LAST FEW HOURS HAVE INCREASED IN THE ERN PANHANDLE...BUT
NEW DEVELOPMENT AS PER THE OPERATIONAL HRRR HAS YET TO OCCUR
ASSOCIATED WITH THE NWD ADVANCING WARM FRONT OVER SRN NEB. SHORT
RANGE MODELS DO HAVE ELEVATED INSTABILITY PRESENT AND SPC
MESOANALYSIS BASED ON RAP SHOWS DEEP MOIST CONVERGENCE INCREASING
TO SUPPORT THIS IDEA. HAVE TRENDED THE HOURLY POP GRIDS TO
REFLECT THIS OCCURRING...DESPITE EXP HRRR AND NSSL WRF NOT
EVOLVING IN THIS MANNER.
ATTENTION THEN TURNS TO ADDITIONAL TSRA DEVELOPMENT THIS
AFTERNOON. AS PREVIOUSLY MENTIONED SHORT WAVE CONTINUES TO MOVE
NEWD INTO THE DAKOTAS TODAY...WEAK LARGE SCALE HEIGHT FALLS ALSO
MOVE OUT OF THE AREA. HOWEVER AS PAC NW UPPER LOW CONTINUES TO
MOVE EWD GOOD HEIGHT FALLS DEVELOP ACROSS WRN MT. THE INCREASED
SWRLY FLOW AHEAD OF THIS FEATURE ALLOWS THE SFC LOW TO REDEVELOP
OVER ERN WY THIS AFTERNOON. AS THIS OCCURS...DEEPER MIXING SOUTH
OF THE SFC LOW WILL DEVELOP THIS AFTERNOON SERVING TO LOWER DEW
POINTS ACROSS THE PANHANDLE. AT THIS SAME TIME...INCREASING SERLY
LOW LEVEL FLOW IN THE TIGHTENING SFC GRADIENT WILL INCREASE DEW
POINTS/LOW LEVEL MOISTURE FURTHER EAST OVER TIME. THE RESULT IS
TO TIGHTEN THE GRADIENT AND EVENTUALLY TO DEVELOP THUNDERSTORMS
ASSOCIATED WITH THIS BOUNDARY. SUITE OF MODELS CONTAIN A WIDE
VARIETY OF SOLUTIONS HOWEVER IN HOW EXTENSIVE THE QPF WILL
BE...IF AT ALL. NAM SUGGESTS A LARGE INCREASE IN PW BY AFTERNOON
/PRIOR TO CONVECTIVE DEVELOPMENT IN THE MODEL/ ASSOCIATED WITH
THE FETCH OF MID/UPPER LEVEL MOISTURE ORIGINATING FROM THE ERN
PAC TROPICS VIA THE SWRLY FLOW. IF DEEP MOIST CONVECTION CAN
DEVELOP...THE WARM MOIST MID LEVELS WOULD ALLOW FOR A CAPE
PROFILE MORE CONDUCIVE TO HEAVY RAIN PRODUCING STORMS AND SHEAR
OF 25-30KTS WOULD BE MARGINAL FOR DEVELOPING STRONG STORMS. AS
ALWAYS HOWEVER SMALL SCALE STORM INTERACTIONS MAY ALLOW FOR MORE
ROBUST DEVELOPMENT ON OCCASION.
TEMPERATURES TODAY WILL BE TRICKY DUE TO LEFT OVER CLOUD COVER
FROM ONGOING CONVECTION AS WELL AS NEW CLOUD COVER FROM
ADDITIONAL DEVELOPMENT THIS AFTERNOON. ASSUMING SRN AREAS WOULD
RECEIVE BEST INSOLATION FOR A LONGER PERIOD OF TIME AND THEREFORE
MAXES ARE HIGHER THERE...THOUGH 90S WILL AGAIN BE COMMON TODAY.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 400 AM CDT SAT SEP 5 2015
SOUTHWEST FLOW TO START THE WEEK TRANSITIONS TO MORE ZONAL FLOW AS
AN UPPER LEVEL LOW LIFTS ACROSS THE NORTHERN ROCKIES INTO THE
CANADIAN PLAINS. A COUPLE OF COLD FRONTS WILL RESULT IN FALLING
TEMPS FOR THE WEEK. MAIN CONCERN IN THE EXTENDED WILL BE TIMING THE
COOL DOWNS AND LOW POP CHANCES THROUGHOUT THE PERIOD.
SUNDAY INTO MONDAY SW FLOW WILL TAP SOME PACIFIC MOISTURE. MODELS
SHOWING SOME MOISTURE FROM THE EASTERN PACIFIC TROPICAL SYSTEMS
GET DRAWN ACROSS THE 4 CORNERS AND TOWARDS THE HIGH PLAINS. THIS
MAY BE ENOUGH TO INCREASE THE MOISTURE IN THE MID/UPPER LEVELS THAT
CAN BE TAPPED BY WEAK DISTURBANCES RIDING ACROSS THE AREA. MODELS
HAVE INCREASE THE LIGHT QPF OVER THE CWA AND CAN NOT ARGUE
NEEDING LOW POPS WITH EACH PASSING WAVE.
MID WEEK A COLD FRONT WILL PUSH ACROSS THE AREA. TIMING OF THE
FRONT AND BETTER MOISTURE RESULTS IN BEST CHANCE FOR PRECIP TO BE
ACROSS THE EASTERN ZONES. BEHIND THE FRONT TEMPS COOL INTO THE
70S...WHICH WOULD BE BELOW NORMAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 102 PM CDT SAT SEP 5 2015
MID AND UPPER LEVEL MOISTURE IN THE FORM OF MID AND HIGH LEVEL
CLOUDINESS CONTINUES TO STREAM NORTHEAST ACROSS THE AREA. A FEW
SCATTERED SHOWERS OR TSTMS COULD DEVELOP FROM THE MID CLOUD DECK
THIS AFTERNOON INTO TONIGHT. GENERALLY EXPECT VFR
CONDITIONS...WITH SOUTH WINDS 10 TO 20 KTS TODAY INTO
TONIGHT...SHIFTING TO THE NORTHWEST AT 10 TO 20 KTS SUNDAY AS
COLD FRONT CROSSES THE AREA.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JWS
SHORT TERM...JWS
LONG TERM...MASEK
AVIATION...TAYLOR
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
656 AM CDT SAT SEP 5 2015
.SYNOPSIS...
ISSUED AT 400 AM CDT SAT SEP 5 2015
WEAK EMBEDDED SHORT WAVE MOVING QUICKLY ACROSS THE CENTRAL
ROCKIES AND ONTO THE HIGH PLAINS IN SWRLY FLOW ALOFT WORKING IN
CONCERT WITH LLJ TO GENERATE SHRA AND ISOLD TSRA ACROSS PORTIONS
OF WRN NEB EARLY THIS MORNING. MEANWHILE UPPER TROUGH AND
ASSOCIATED LOW OVER THE PAC NW STARTING TO MOVE EWD WHILE HEIGHTS
RISE ACROSS THE PLAINS. THESE TWO THINGS CONTRIBUTING TO
TIGHTEN/INCREASE THE UPPER FLOW AHEAD OF THE LOW IN THE NW.
MOISTURE AND ASSOCIATED CONVECTIVE ACTIVITY FROM TROPICAL STORM
KEVIN MOVING ONSHORE ON THE BAJA PENINSULA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 400 AM CDT SAT SEP 5 2015
FORECAST ISSUES FOR EARLY THIS MORNING INVOLVES THE POTENTIAL FOR
ADDITIONAL CONVECTIVE DEVELOPMENT IN SRN/WRN NEB WHICH SEVERAL OF
THE CAMS SUGGEST WILL HAPPEN THROUGH THE MORNING. RADAR ECHOES
OVER THE LAST FEW HOURS HAVE INCREASED IN THE ERN PANHANDLE...BUT
NEW DEVELOPMENT AS PER THE OPERATIONAL HRRR HAS YET TO OCCUR
ASSOCIATED WITH THE NWD ADVANCING WARM FRONT OVER SRN NEB. SHORT
RANGE MODELS DO HAVE ELEVATED INSTABILITY PRESENT AND SPC
MESOANALYSIS BASED ON RAP SHOWS DEEP MOIST CONVERGENCE INCREASING
TO SUPPORT THIS IDEA. HAVE TRENDED THE HOURLY POP GRIDS TO
REFLECT THIS OCCURRING...DESPITE EXP HRRR AND NSSL WRF NOT
EVOLVING IN THIS MANNER.
ATTENTION THEN TURNS TO ADDITIONAL TSRA DEVELOPMENT THIS
AFTERNOON. AS PREVIOUSLY MENTIONED SHORT WAVE CONTINUES TO MOVE
NEWD INTO THE DAKOTAS TODAY...WEAK LARGE SCALE HEIGHT FALLS ALSO
MOVE OUT OF THE AREA. HOWEVER AS PAC NW UPPER LOW CONTINUES TO
MOVE EWD GOOD HEIGHT FALLS DEVELOP ACROSS WRN MT. THE INCREASED
SWRLY FLOW AHEAD OF THIS FEATURE ALLOWS THE SFC LOW TO REDEVELOP
OVER ERN WY THIS AFTERNOON. AS THIS OCCURS...DEEPER MIXING SOUTH
OF THE SFC LOW WILL DEVELOP THIS AFTERNOON SERVING TO LOWER DEW
POINTS ACROSS THE PANHANDLE. AT THIS SAME TIME...INCREASING SERLY
LOW LEVEL FLOW IN THE TIGHTENING SFC GRADIENT WILL INCREASE DEW
POINTS/LOW LEVEL MOISTURE FURTHER EAST OVER TIME. THE RESULT IS
TO TIGHTEN THE GRADIENT AND EVENTUALLY TO DEVELOP THUNDERSTORMS
ASSOCIATED WITH THIS BOUNDARY. SUITE OF MODELS CONTAIN A WIDE
VARIETY OF SOLUTIONS HOWEVER IN HOW EXTENSIVE THE QPF WILL
BE...IF AT ALL. NAM SUGGESTS A LARGE INCREASE IN PW BY AFTERNOON
/PRIOR TO CONVECTIVE DEVELOPMENT IN THE MODEL/ ASSOCIATED WITH
THE FETCH OF MID/UPPER LEVEL MOISTURE ORIGINATING FROM THE ERN
PAC TROPICS VIA THE SWRLY FLOW. IF DEEP MOIST CONVECTION CAN
DEVELOP...THE WARM MOIST MID LEVELS WOULD ALLOW FOR A CAPE
PROFILE MORE CONDUCIVE TO HEAVY RAIN PRODUCING STORMS AND SHEAR
OF 25-30KTS WOULD BE MARGINAL FOR DEVELOPING STRONG STORMS. AS
ALWAYS HOWEVER SMALL SCALE STORM INTERACTIONS MAY ALLOW FOR MORE
ROBUST DEVELOPMENT ON OCCASION.
TEMPERATURES TODAY WILL BE TRICKY DUE TO LEFT OVER CLOUD COVER
FROM ONGOING CONVECTION AS WELL AS NEW CLOUD COVER FROM
ADDITIONAL DEVELOPMENT THIS AFTERNOON. ASSUMING SRN AREAS WOULD
RECEIVE BEST INSOLATION FOR A LONGER PERIOD OF TIME AND THEREFORE
MAXES ARE HIGHER THERE...THOUGH 90S WILL AGAIN BE COMMON TODAY.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 400 AM CDT SAT SEP 5 2015
SOUTHWEST FLOW TO START THE WEEK TRANSITIONS TO MORE ZONAL FLOW AS
AN UPPER LEVEL LOW LIFTS ACROSS THE NORTHERN ROCKIES INTO THE
CANADIAN PLAINS. A COUPLE OF COLD FRONTS WILL RESULT IN FALLING
TEMPS FOR THE WEEK. MAIN CONCERN IN THE EXTENDED WILL BE TIMING THE
COOL DOWNS AND LOW POP CHANCES THROUGHOUT THE PERIOD.
SUNDAY INTO MONDAY SW FLOW WILL TAP SOME PACIFIC MOISTURE. MODELS
SHOWING SOME MOISTURE FROM THE EASTERN PACIFIC TROPICAL SYSTEMS
GET DRAWN ACROSS THE 4 CORNERS AND TOWARDS THE HIGH PLAINS. THIS
MAY BE ENOUGH TO INCREASE THE MOISTURE IN THE MID/UPPER LEVELS THAT
CAN BE TAPPED BY WEAK DISTURBANCES RIDING ACROSS THE AREA. MODELS
HAVE INCREASE THE LIGHT QPF OVER THE CWA AND CAN NOT ARGUE
NEEDING LOW POPS WITH EACH PASSING WAVE.
MID WEEK A COLD FRONT WILL PUSH ACROSS THE AREA. TIMING OF THE
FRONT AND BETTER MOISTURE RESULTS IN BEST CHANCE FOR PRECIP TO BE
ACROSS THE EASTERN ZONES. BEHIND THE FRONT TEMPS COOL INTO THE
70S...WHICH WOULD BE BELOW NORMAL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 655 AM CDT SAT SEP 5 2015
FCST DIFFICULTIES TODAY INVOLVE THE PRECIP FCST AND ASSOCIATED
CLOUD COVER. ONGOING SHRA OVER NC NEB HAS HAD A COUPLE OF
LIGHTNING FLASHES BUT OVERALL INTENSITY NOT TOO IMPRESSIVE.
OPERATIONAL HRRR HAS HAD POOR RUN TO RUN CONSISTENCY AND EARLIER
DEVELOPED TSRA OVER THE SW NEAR THE WARM FRONT WITH ELEVATED
INSTABILITY BUT PRECIP NEVER MATERIALIZED THOUGH MID LEVEL
CLOUDINESS DID. AGAIN SEVERAL POTENTIAL SOLUTIONS IN THE
CONVECTIVE INITIATION ENVELOPE FOR LATER THIS MORNING AS WELL AS
THIS AFTERNOON WHEN LL FLOW INCREASES IN RESPSONE TO DEVELOPING
LOW PRESSURE IN ERN WY. NAM HAS BEEN TOO AGGRESSIVE WITH DRY LOWER
LAYERS PRESENT UP THROUGH 12Z THIS MORNING. END RESULT IS LITTLE
CONFIDENCE IN ANY ONE SOLUTION. IN ADDITION...BASED ON LATEST SFC OBS
AND RADAR VWP THERE DOES EXISTS SOME LOW LEVEL DIRECTIONAL AND
SPEED SHEAR...BUT AT THIS TIME THE DIFFERENCE IS BELOW CRITERIA.
AS SFC LOW DEVELPS LATER...THERE STILL APPEARS TO BE SOME
TIGHTENING OF THE LOW LEVEL MOISTURE GRAIENT SO HAVE INCLUDED SOME
GUSTS IN TAFS AND...LIKE HAS BEEN THE CASE WITH THE LAST WEEK OR
SO...POTENTIAL CONVECTIVE DEVELOPMENT LOOKS POSSIBLE BUT LACK OF
SHEAR AND LARGE CAPE SHOULD KEEP COVERAGE AND INTENSITY TO A
MINIMUM. FCST CONFIDENCE IS BELOW AVERAGE ON TIMING OF CONVECTION
AT KLBF AND KVTN FOR LATER TODAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JWS
SHORT TERM...JWS
LONG TERM...MASEK
AVIATION...JWS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
400 AM CDT SAT SEP 5 2015
.SYNOPSIS...
ISSUED AT 400 AM CDT SAT SEP 5 2015
WEAK EMBEDDED SHORT WAVE MOVING QUICKLY ACROSS THE CENTRAL
ROCKIES AND ONTO THE HIGH PLAINS IN SWRLY FLOW ALOFT WORKING IN
CONCERT WITH LLJ TO GENERATE SHRA AND ISOLD TSRA ACROSS PORTIONS
OF WRN NEB EARLY THIS MORNING. MEANWHILE UPPER TROUGH AND
ASSOCIATED LOW OVER THE PAC NW STARTING TO MOVE EWD WHILE HEIGHTS
RISE ACROSS THE PLAINS. THESE TWO THINGS CONTRIBUTING TO
TIGHTEN/INCREASE THE UPPER FLOW AHEAD OF THE LOW IN THE NW.
MOISTURE AND ASSOCIATED CONVECTIVE ACTIVITY FROM TROPICAL STORM
KEVIN MOVING ONSHORE ON THE BAJA PENINSULA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 400 AM CDT SAT SEP 5 2015
FORECAST ISSUES FOR EARLY THIS MORNING INVOLVES THE POTENTIAL FOR
ADDITIONAL CONVECTIVE DEVELOPMENT IN SRN/WRN NEB WHICH SEVERAL OF
THE CAMS SUGGEST WILL HAPPEN THROUGH THE MORNING. RADAR ECHOES
OVER THE LAST FEW HOURS HAVE INCREASED IN THE ERN PANHANDLE...BUT
NEW DEVELOPMENT AS PER THE OPERATIONAL HRRR HAS YET TO OCCUR
ASSOCIATED WITH THE NWD ADVANCING WARM FRONT OVER SRN NEB. SHORT
RANGE MODELS DO HAVE ELEVATED INSTABILITY PRESENT AND SPC
MESOANALYSIS BASED ON RAP SHOWS DEEP MOIST CONVERGENCE INCREASING
TO SUPPORT THIS IDEA. HAVE TRENDED THE HOURLY POP GRIDS TO
REFLECT THIS OCCURRING...DESPITE EXP HRRR AND NSSL WRF NOT
EVOLVING IN THIS MANNER.
ATTENTION THEN TURNS TO ADDITIONAL TSRA DEVELOPMENT THIS
AFTERNOON. AS PREVIOUSLY MENTIONED SHORT WAVE CONTINUES TO MOVE
NEWD INTO THE DAKOTAS TODAY...WEAK LARGE SCALE HEIGHT FALLS ALSO
MOVE OUT OF THE AREA. HOWEVER AS PAC NW UPPER LOW CONTINUES TO
MOVE EWD GOOD HEIGHT FALLS DEVELOP ACROSS WRN MT. THE INCREASED
SWRLY FLOW AHEAD OF THIS FEATURE ALLOWS THE SFC LOW TO REDEVELOP
OVER ERN WY THIS AFTERNOON. AS THIS OCCURS...DEEPER MIXING SOUTH
OF THE SFC LOW WILL DEVELOP THIS AFTERNOON SERVING TO LOWER DEW
POINTS ACROSS THE PANHANDLE. AT THIS SAME TIME...INCREASING SERLY
LOW LEVEL FLOW IN THE TIGHTENING SFC GRADIENT WILL INCREASE DEW
POINTS/LOW LEVEL MOISTURE FURTHER EAST OVER TIME. THE RESULT IS
TO TIGHTEN THE GRADIENT AND EVENTUALLY TO DEVELOP THUNDERSTORMS
ASSOCIATED WITH THIS BOUNDARY. SUITE OF MODELS CONTAIN A WIDE
VARIETY OF SOLUTIONS HOWEVER IN HOW EXTENSIVE THE QPF WILL
BE...IF AT ALL. NAM SUGGESTS A LARGE INCREASE IN PW BY AFTERNOON
/PRIOR TO CONVECTIVE DEVELOPMENT IN THE MODEL/ ASSOCIATED WITH
THE FETCH OF MID/UPPER LEVEL MOISTURE ORIGINATING FROM THE ERN
PAC TROPICS VIA THE SWRLY FLOW. IF DEEP MOIST CONVECTION CAN
DEVELOP...THE WARM MOIST MID LEVELS WOULD ALLOW FOR A CAPE
PROFILE MORE CONDUCIVE TO HEAVY RAIN PRODUCING STORMS AND SHEAR
OF 25-30KTS WOULD BE MARGINAL FOR DEVELOPING STRONG STORMS. AS
ALWAYS HOWEVER SMALL SCALE STORM INTERACTIONS MAY ALLOW FOR MORE
ROBUST DEVELOPMENT ON OCCASION.
TEMPERATURES TODAY WILL BE TRICKY DUE TO LEFT OVER CLOUD COVER
FROM ONGOING CONVECTION AS WELL AS NEW CLOUD COVER FROM
ADDITIONAL DEVELOPMENT THIS AFTERNOON. ASSUMING SRN AREAS WOULD
RECEIVE BEST INSOLATION FOR A LONGER PERIOD OF TIME AND THEREFORE
MAXES ARE HIGHER THERE...THOUGH 90S WILL AGAIN BE COMMON TODAY.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 400 AM CDT SAT SEP 5 2015
SOUTHWEST FLOW TO START THE WEEK TRANSITIONS TO MORE ZONAL FLOW AS
AN UPPER LEVEL LOW LIFTS ACROSS THE NORTHERN ROCKIES INTO THE
CANADIAN PLAINS. A COUPLE OF COLD FRONTS WILL RESULT IN FALLING
TEMPS FOR THE WEEK. MAIN CONCERN IN THE EXTENDED WILL BE TIMING THE
COOL DOWNS AND LOW POP CHANCES THROUGHOUT THE PERIOD.
SUNDAY INTO MONDAY SW FLOW WILL TAP SOME PACIFIC MOISTURE. MODELS
SHOWING SOME MOISTURE FROM THE EASTERN PACIFIC TROPICAL SYSTEMS
GET DRAWN ACROSS THE 4 CORNERS AND TOWARDS THE HIGH PLAINS. THIS
MAY BE ENOUGH TO INCREASE THE MOISTURE IN THE MID/UPPER LEVELS THAT
CAN BE TAPPED BY WEAK DISTURBANCES RIDING ACROSS THE AREA. MODELS
HAVE INCREASE THE LIGHT QPF OVER THE CWA AND CAN NOT ARGUE
NEEDING LOW POPS WITH EACH PASSING WAVE.
MID WEEK A COLD FRONT WILL PUSH ACROSS THE AREA. TIMING OF THE
FRONT AND BETTER MOISTURE RESULTS IN BEST CHANCE FOR PRECIP TO BE
ACROSS THE EASTERN ZONES. BEHIND THE FRONT TEMPS COOL INTO THE
70S...WHICH WOULD BE BELOW NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1127 PM CDT FRI SEP 4 2015
ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED THE REST OF
TONIGHT IN WESTERN NEBRASKA. CONFIDENCE IN SHOWERS/THUNDERSTORMS
OCCURRING BEFORE 15Z IS LOW. IN FACT...THE PROBABILITY OF
SHOWERS/THUNDERSTORMS THROUGH THE PERIOD IS 30 PERCENT OR LOWER
WHICH DOES NOT INSPIRE A LOT OF CONFIDENCE THAT THEY WILL OCCUR
AT LBF OR VTN. THE BEST CONSENSUS AMONG THE EVENING MODEL RUNS
WOULD BE THAT THE CHANCES OF PRECIPITATION WILL BE 18-01Z
SATURDAY. WE HAVE ACCOUNTED FOR THAT BY USING PROB30 IN THE
FORECASTS FOR LBF AND VTN 19-24Z.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JWS
SHORT TERM...JWS
LONG TERM...MASEK
AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
901 PM PDT SUN SEP 6 2015
.SYNOPSIS...AN INFLUX OF TROPICAL MOISTURE WILL RESULT IN THE
POSSIBILITY OF SHOWERS AND THUNDERSTORMS FROM AREAS NEAR THE
COLORADO RIVER VALLEY AND TO THE EAST THROUGH TUESDAY EVENING.
OTHERWISE EXPECT DRY CONDITIONS ACROSS THE AREA. TEMPERATURES WILL
STEADILY WARM THROUGH THURSDAY THEN REMAIN ABOVE NORMAL THROUGH THE
END OF THE WEEK.
&&
.UPDATE...WITH THE LOSS OF HEATING, SHOWERS AND THUNDERSTORMS WERE
ON A DOWNWARD TREND AND IN THE LAST 30 MINUTES MOST OF THE ACTIVITY
IN THE MOUNT TRUMBULL AREA HAS DECLINED IN INTENSITY. THE HRRR STILL
HINTS SOME ACTIVITY MAY TRY TO POP UP OVERNIGHT IN NORTHEAST CLARK
AND SOUTHEAST LINCOLN COUNTIES. THIS AREA WAS NOT WORKED OVER TODAY
YET, SO THIS HOLDS SOME PROSPECT. IN ADDITION, WE DID SEE A
THUNDERSTORM POP UP LAST NIGHT AROUND MIDNIGHT NORTHEAST OF SOUTH
COVE. SO, WITH A SIMILAR PATTERN IN PLACE TONIGHT, THIS IS NOT
TOTALLY OUT OF THE QUESTION. HOWEVER, IT APPEARS THE POTENTIAL FOR
ANY SHOWERS AND THUNDERSTORMS FROM BOULDER BEACH ON SOUTHWEST TOWARD
LAKE HAVASU AND WEST TOWARD SEARCHLIGHT AND VIDAL JUNCTION IS OVER
WITH AND I REMOVED THE MENTION OF SHOWERS AND THUNDERSTORMS FROM
THESE AREAS. THE REST OF THE FORECAST LOOKS IN GOOD SHAPE AT THIS
TIME.
&&
.AVIATION...FOR MCCARRAN...WINDS WILL FAVOR TYPICAL DIURNAL
DIRECTIONS THROUGH MONDAY EVENING. THERE AGAIN WILL BE THE POTENTIAL
BETWEEN 14Z AND 19Z WHEN WINDS WILL RANGE BETWEEN 090 AND 160
DEGREES AT 4-8 KTS BEFORE TRENDING MORE SOUTH TO SOUTHWEST. THERE IS
ALSO SOME POTENTIAL FOR WINDS TO START SOUTHEAST, GO MORE SOUTHERLY
AND THEN GO BACK AN EAST OR SOUTHEAST COMPONENT IN THIS TIME FRAME.
THIS COULD CAUSE CONFIGURATION ISSUES. FEW-SCT CLOUDS AOA 10K FEET.
ISOLATED SHRA/TSRA ARE POSSIBLE MAINLY AFTER 18Z MONDAY IN THE PEACH
SPRINGS AND MORMON MESA APPROACH CORRIDORS. THERE IS THE POTENTIAL
FOR OUTFLOW WINDS FROM SHRA/TSRA TO IMPACT THE AIRPORT COMPLEX IN
THE AFTERNOON AND EARLY EVENING ON MONDAY WHICH COULD CAUSE GUSTY
AND ERRATIC WINDS.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...GENERALLY SOUTH WINDS AROUND 10 KTS WITH GUSTS UP TO 20
KTS AGAIN ON LABOR DAY. WINDS SHOULD RELAX ACROSS THE AREA BY
TUESDAY AND FOLLOW TYPICAL DIURNAL TRENDS. SHRA/TSRA REMAINS
POSSIBLE LABOR DAY AFTER 18Z AND MAINLY ENDING BY 06Z TUESDAY EAST
OF A LINE FROM KSGU-KLAS-KHII. SCT-BKN CLOUDS AOA 7K-12K FEET IN AND
NEAR ANY SHRA/TSRA WITH LOCALLY REDUCED CIGS AND VSBY. OTHERWISE
EXPECT A CLEAR SKY.
&&
.PREVIOUS DISCUSSION...
ISSUED AT 135 PM PDT SUN SEP 6 2015
.SHORT TERM...THROUGH TUESDAY NIGHT.
BETTER MOISTURE IN MOHAVE COUNTY WILL CONTINUE TO SUPPORT THE MORE
SUBSTANTIAL THREAT OF THUNDERSTORMS OVER THE NEXT COUPLE OF DAYS.
FLOW/STORM MOTION SHOULD REMAIN FAST ENOUGH TO LIMIT FLASH FLOODING
POTENTIAL WITH ANY SINGLE CELL...WITH FLOODING THREAT LIMITED TO ANY
TRAINING OR CLUSTERS THAT MAY DEVELOP. HIGH RES GUIDANCE INDICATES
MOST ACTIVITY SUBSIDING AFTER SUNSET...BUT ACTIVITY HAS LINGER A FEW
HOURS AFTER THE LAST FEW NIGHTS...AND THERE WOULD STILL REMAIN A
THREAT FOR AT LEAST ISOLATED ACTIVITY THROUGH THE NIGHT.
LABOR DAY STILL LOOKS LIKE A PLEASANT DAY FOR MOST OF THE AREA WITH
LIGHTER WINDS THAN THE LAST FEW DAYS AND TEMPS ON THE COOL SIDE OF
SEASONAL NORMALS. NOT MUCH WILL LIKELY CHANGE WITH MOISTURE AND
THUNDERSTORM CHANCES...ESPECIALLY FOR MOHAVE COUNTY. ANY SPECIFICS
WILL LIKELY HAVE TO BE WORKED OUT AFTER WE SEE HOW ACTIVITY DEVELOPS
TODAY/TONIGHT. ENOUGH INSTABILITY MAY DEVELOP IN SOUTHEASTERN
PORTIONS OF LINCOLN COUNTY, SO SLIGHT POPS HAVE BEEN ADDED FOR
MONDAY AFTERNOON.
MOISTURE LOOKS TO DECREASE OVER THE NORTHERN HALF OF THE AREA, WHILE
INCREASING SOMEWHAT IN WESTERN SAN BERNARDINO COUNTY ON TUESDAY AS
FLOW RELAXES AND BECOMES MORE ANTICYCLONIC WITH A BUILDING HIGH OVER
THE AREA. TEMPS WILL BE WARMING FOR TUESDAY AND BEYOND.
.LONG TERM...WEDNESDAY THROUGH SUNDAY.
IT LOOKS LIKE WE WILL SEE AT LEAST ONE LAST GASP OF SUMMER HEAT THE
SECOND HALF OF THE WEEK. A STRONG HIGH OVER NORTHERN MEXICO IS
FORECAST TO EXPAND UP ACROSS CALIFORNIA AND NEVADA AND MERGE WITH
THE EASTERN PACIFIC RIDGE. THE LATEST ECMWF AND GFS SOLUTIONS ARE
NOW IN GOOD AGREEMENT WITH THIS PATTERN. THE RESULT WILL BE A DRY
NORTHWEST TO NORTHERLY FLOW ALOFT WITH HIGH TEMPERATURES CLIMBING TO
BETWEEN 105 AND 110 DEGREES ACROSS MUCH OF THE MOJAVE DESERT AND
COLORADO RIVER VALLEY REGION FROM THURSDAY INTO THE WEEKEND.
MOISTURE ASSOCIATED WITH A TROPICAL SYSTEM OFF THE COAST OF BAJA
WOULD LARGELY BE HELD SOUTH OF THE MEXICO BORDER AND OFF THE SOCAL
COAST IN THIS PATTERN.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
UPDATE/AVIATION...STACHELSKI
SHORT TERM...STEELE
LONG TERM...ADAIR
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
935 AM PDT SAT SEP 5 2015
.SYNOPSIS...A FEED OF TROPICAL MOISTURE INTO ARIZONA WILL STILL
ALLOW FOR A SHOWER OR THUNDERSTORM AROUND THROUGH TUESDAY. OTHERWISE
A STORM SYSTEM PASSING ACROSS NEVADA TODAY WILL RESULT IN ANOTHER
DAY OF GUSTY SOUTH TO SOUTHWEST WINDS ACROSS THE AREA ESPECIALLY IN
LINCOLN COUNTY. WINDS WILL DECREASE IN ALL AREAS ON SUNDAY.
TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH THE WEEKEND THEN
RETURN TO ABOVE NORMAL BY THE END OF NEXT WEEK.
&&
.UPDATE...OVERALL THE FORECAST IS IN GOOD SHAPE. I DID NUDGE POPS
UPWARDS ACROSS EASTERN MOHAVE COUNTY MAINLY EAST OF KINGMAN. MODELS
AGREE ON INSTABILITY AXIS ROUGHLY ALONG THE COLORADO RIVER AND
EASTWARD. WHILE SOUTHWEST FLOW WILL WORK TO BRING IN DRIER AIR TODAY
ENOUGH MOISTURE REMAINS IN PLACE FOR SOME ISOLATED ACTIVITY ACROSS
THESE AREAS LATER THIS AFTERNOON. COVERAGE HOWEVER WILL BE HIGHLY
ISOLATED AT BEST.
-OUTLER-
&&
.SHORT TERM...TODAY THROUGH SUNDAY NIGHT.
A SOUTHWEST FLOW ALOFT WAS TRANSPORTING A FEED OF TROPICAL MOISTURE
NORTHEAST TOWARD ARIZONA THIS MORNING. THIS IS EVIDENT FROM
INSPECTING INFRARED SATELLITE IMAGERY AS ONE CAN SEE AN EXTENSIVE
AMOUNT OF CLOUDS ACROSS THE EASTERN TWO-THIRDS OF THE STATE. OUR
AREA WILL BE ON THE EDGE OF THIS MOISTURE FEED BUT WE NEVER REALLY
APPEAR TO SHAKE IT AWAY ALTOGETHER DESPITE AN APPROACHING MID/UPPER
LEVEL TROUGH WORKING INTO CALIFORNIA AND WESTERN NEVADA. AS A RESULT
ONCE AGAIN TODAY WE SHOULD STAND THE PROSPECT OF SEEING CUMULUS POP
UP IN EASTERN MOHAVE COUNTY AND POSSIBLY A SHOWER OR THUNDERSTORM
ESPECIALLY TOWARD THE MOUNT TRUMBULL AREA. THE HRRR STILL SHOWS SOME
WEAK RETURNS THIS AFTERNOON AS FAR WEST AS THE COLORADO RIVER BUT
THE DRIER AIR ADVANCING EAST ON WATER VAPOR RESULTS IN MY THOUGHT
THAT AT BEST THIS WOULD BE A FEW CUMULUS.
THERE IS STILL A BELT OF STRONGER WINDS ALOFT COURTESY OF THE JET
STREAM CROSSING THE EASTERN PARTS OF THE AREA TODAY. HOWEVER,
SEVERAL FACTORS DO NOT SUPPORT WINDS AS STRONG TODAY. THE SURFACE
PRESSURE GRADIENT IS VERY, VERY WEAK AND NOT EVEN ON PAR WITH WHAT
WE WOULD SEE ON A NORMAL DAY WITH JUST THERMALS. SECONDLY, THE 700
MB WINDS ON THE GFS AND ECMWF ARE MUCH LOWER TODAY - ABOUT 20 TO 25
KTS. AS A RESULT, I HAVE CANNED THE WIND ADVISORIES FOR NORTHEAST
CLARK AND NORTHERN MOHAVE COUNTY. IN LINCOLN COUNTY, THERE IS SOME
HOPE THAT WE MAY SEE A FEW POCKETS IN EASTERN AREAS REACH THE 40 MPH
GUST MARK FOR 3 HOURS SUCH AS PANACA SUMMIT, EAGLE VALLEY, SPRING
VALLEY STATE PARK AND BEAVER DAM. THUS THE WIND ADVISORY REMAINS IN
EFFECT THERE FOR LATE THIS MORNING THROUGH EARLY THIS EVENING.
TEMPS WILL DROP A FEW DEGREES TODAY BUT WE STILL LEANED TOWARD THE
WARMER END OF GUIDANCE FOR HIGHS. LOWS TONIGHT WERE TWEAKED UP A BIT
BASED ON A BLEND OF THE LATEST GUIDANCE BUT IT WILL STILL BE A
REFRESHING NIGHT AND START TO SUNDAY WITH LESS WIND. SOME OF THE
COLDER SPOTS IN LINCOLN COUNTY LIKE SPRING VALLEY STATE PARK AND
URSINE MAY DROP INTO THE 30S AS WILL THE HIGHER SPOTS IN THE SIERRA
AND WHITE MOUNTAINS AS WELL AS WELL UP ON MOUNT CHARLESTON. BE
PREPARED FOR THE CHILL IF YOU PLAN TO CAMP.
THE TROUGH AXIS WILL SORT OF GET HUNG UP ACROSS SOUTH-CENTRAL NEVADA
ON SUNDAY BEFORE DISSOLVING. AS A RESULT, MOHAVE COUNTY REMAINS IN
ENOUGH OF A SOUTHWEST FLOW TO ENTRAIN MOISTURE ON IN AND THE CHANCE
OF A SHOWER OR THUNDERSTORM WAS ADDED AGAIN INTO EASTERN AREAS FOR
SUNDAY. THE REST OF THE CWFA LOOKS DRY. TEMPS WILL START TO REBOUND
AND JUMP UP A DEGREE OR TWO. WITH LESS UPPER LEVEL SUPPORT WINDS
WILL ALSO BE LIGHTER. OVERALL FOR MOST AREAS THIS WILL BE THE PICK
OF THE LABOR DAY WEEKEND FOR THE BEST WEATHER. SUNDAY NIGHT`S LOWS
WERE RAISED UP AS WELL SEVERAL DEGREES BASED ON THE LATEST GUIDANCE.
ENJOY THIS LITTLE BREAK FROM THE INTENSITY OF SUMMER.
.LONG TERM...MONDAY THROUGH SATURDAY.
THE MEDIUM RANGE MODELS INDICATE A GENERALLY DRY PATTERN FOR MOST OF
THE FORECAST AREA WITH A WARMING TREND THE SECOND HALF OF THE WEEK.
THERE IS SOME UNCERTAINTY WITH MOISTURE FORECASTS BETWEEN THE GFS
AND ECMWF BUT NEITHER SOLUTION DEPICTS SIGNIFICANT MOISTURE
SPREADING INTO THE AREA. THE GFS CONTINUES TO INDICATE LOW TO MID
LEVEL MOISTURE LINGERING OVER NORTHWEST ARIZONA THROUGH LABOR DAY
AND IT IS WORTH MENTIONING A SLIGHT CHANCE OF THUNDERSTORMS OVER THE
EASTERN HALF OF MOHAVE COUNTY. AN INCREASINGLY DRY WESTERLY FLOW
DEVELOPING TUESDAY SHOULD PUSH MOST OF THE MOISTURE TO THE EAST
TUESDAY BUT A SLIGHT CHANCE OF THUNDERSTORMS STILL EXISTS FOR THE
ARIZONA STRIP.
WE WILL NEED TO KEEP AN EYE ON ANOTHER TROPICAL SYSTEM NEAR SOUTHERN
BAJA WHICH THE MODELS INDICATE WILL DEVELOP AND MOVE TO THE WEST
NORTHWEST THOUGH THERE IS LITTLE CHANCE OF ANY SIGNIFICANT MOISTURE
BEING PULLED OUR WAY. THE WARMING TREND WILL COME DUE TO AN EASTERN
PACIFIC RIDGE MERGING WITH A RIDGE NEAR NORTHERN MEXICO EXPANDING TO
THE NORTHWEST AFTER WEDNESDAY. THE ECMWF SOLUTION IS A LITTLE WARMER
THAN THE GFS AND PROVIDES HIGH TEMPS SEVERAL DEGREES ABOVE NORMAL
WITH TRIPLE DIGIT READINGS BACK OVER MUCH OF THE MOJAVE DESERT
REGION FROM WEDNESDAY INTO NEXT WEEKEND.
&&
.AVIATION...FOR MCCARRAN...WINDS WILL AGAIN INCREASE LATE THIS
MORNING AND BE STRONGEST IN THE AFTERNOON AND EARLY EVENING GUSTING
OVER 20 KTS. THERE IS A SMALL WINDOW BETWEEN 14Z AND 17Z TODAY WHERE
WIND DIRECTION WILL BE NEAR THE 160 DEGREE LINE WHICH MAY CAUSE
CONFIGURATION ISSUES.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...THERE WILL AGAIN BE THE POSSIBILITY OF A SHRA/TSRA
TODAY AFTER 18Z AND BEFORE 06Z SUNDAY IN AND AROUND MT TRUMBILL. ALL
OTHER AREAS SHOULD BE DRY. OTHERWISE LOOK FOR SOUTH TO SOUTHWEST
WINDS INCREASING BETWEEN 16Z AND 20Z TODAY WITH GUSTS OF 20-30 KTS
EXCEPT IN LINCOLN COUNTY WHERE GUSTS TO AROUND 35 KTS ARE POSSIBLE.
WINDS WILL SLOWLY DECREASE BETWEEN 03Z AND 06Z SUNDAY. A CLEAR SKY
IS EXPECTED EXCEPT IN AREAS EAST AND NORTHEAST OF KIGM WHERE FEW-SCT
CLOUDS AOA 10K-15K FEET WILL BE AROUND IN THE AFTERNOON AND EARLY
EVENING.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
SHORT TERM/AVIATION...STACHELSKI
LONG TERM...ADAIR
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
248 AM PDT SAT SEP 5 2015
.SYNOPSIS...A FEED OF TROPICAL MOISTURE INTO ARIZONA WILL STILL
ALLOW FOR A SHOWER OR THUNDERSTORM AROUND THROUGH TUESDAY. OTHERWISE
A STORM SYSTEM PASSING ACROSS NEVADA TODAY WILL RESULT IN ANOTHER
DAY OF GUSTY SOUTH TO SOUTHWEST WINDS ACROSS THE AREA ESPECIALLY IN
LINCOLN COUNTY. WINDS WILL DECREASE IN ALL AREAS ON SUNDAY.
TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH THE WEEKEND THEN
RETURN TO ABOVE NORMAL BY THE END OF NEXT WEEK.
&&
.SHORT TERM...TODAY THROUGH SUNDAY NIGHT.
A SOUTHWEST FLOW ALOFT WAS TRANSPORTING A FEED OF TROPICAL MOISTURE
NORTHEAST TOWARD ARIZONA THIS MORNING. THIS IS EVIDENT FROM
INSPECTING INFRARED SATELLITE IMAGERY AS ONE CAN SEE AN EXTENSIVE
AMOUNT OF CLOUDS ACROSS THE EASTERN TWO-THIRDS OF THE STATE. OUR
AREA WILL BE ON THE EDGE OF THIS MOISTURE FEED BUT WE NEVER REALLY
APPEAR TO SHAKE IT AWAY ALTOGETHER DESPITE AN APPROACHING MID/UPPER
LEVEL TROUGH WORKING INTO CALIFORNIA AND WESTERN NEVADA. AS A RESULT
ONCE AGAIN TODAY WE SHOULD STAND THE PROSPECT OF SEEING CUMULUS POP
UP IN EASTERN MOHAVE COUNTY AND POSSIBLY A SHOWER OR THUNDERSTORM
ESPECIALLY TOWARD THE MOUNT TRUMBULL AREA. THE HRRR STILL SHOWS SOME
WEAK RETURNS THIS AFTERNOON AS FAR WEST AS THE COLORADO RIVER BUT
THE DRIER AIR ADVANCING EAST ON WATER VAPOR RESULTS IN MY THOUGHT
THAT AT BEST THIS WOULD BE A FEW CUMULUS.
THERE IS STILL A BELT OF STRONGER WINDS ALOFT COURTESY OF THE JET
STREAM CROSSING THE EASTERN PARTS OF THE AREA TODAY. HOWEVER,
SEVERAL FACTORS DO NOT SUPPORT WINDS AS STRONG TODAY. THE SURFACE
PRESSURE GRADIENT IS VERY, VERY WEAK AND NOT EVEN ON PAR WITH WHAT
WE WOULD SEE ON A NORMAL DAY WITH JUST THERMALS. SECONDLY, THE 700
MB WINDS ON THE GFS AND ECMWF ARE MUCH LOWER TODAY - ABOUT 20 TO 25
KTS. AS A RESULT, I HAVE CANNED THE WIND ADVISORIES FOR NORTHEAST
CLARK AND NORTHERN MOHAVE COUNTY. IN LINCOLN COUNTY, THERE IS SOME
HOPE THAT WE MAY SEE A FEW POCKETS IN EASTERN AREAS REACH THE 40 MPH
GUST MARK FOR 3 HOURS SUCH AS PANACA SUMMIT, EAGLE VALLEY, SPRING
VALLEY STATE PARK AND BEAVER DAM. THUS THE WIND ADVISORY REMAINS IN
EFFECT THERE FOR LATE THIS MORNING THROUGH EARLY THIS EVENING.
TEMPS WILL DROP A FEW DEGREES TODAY BUT WE STILL LEANED TOWARD THE
WARMER END OF GUIDANCE FOR HIGHS. LOWS TONIGHT WERE TWEAKED UP A BIT
BASED ON A BLEND OF THE LATEST GUIDANCE BUT IT WILL STILL BE A
REFRESHING NIGHT AND START TO SUNDAY WITH LESS WIND. SOME OF THE
COLDER SPOTS IN LINCOLN COUNTY LIKE SPRING VALLEY STATE PARK AND
URSINE MAY DROP INTO THE 30S AS WILL THE HIGHER SPOTS IN THE SIERRA
AND WHITE MOUNTAINS AS WELL AS WELL UP ON MOUNT CHARLESTON. BE
PREPARED FOR THE CHILL IF YOU PLAN TO CAMP.
THE TROUGH AXIS WILL SORT OF GET HUNG UP ACROSS SOUTH-CENTRAL NEVADA
ON SUNDAY BEFORE DISSOLVING. AS A RESULT, MOHAVE COUNTY REMAINS IN
ENOUGH OF A SOUTHWEST FLOW TO ENTRAIN MOISTURE ON IN AND THE CHANCE
OF A SHOWER OR THUNDERSTORM WAS ADDED AGAIN INTO EASTERN AREAS FOR
SUNDAY. THE REST OF THE CWFA LOOKS DRY. TEMPS WILL START TO REBOUND
AND JUMP UP A DEGREE OR TWO. WITH LESS UPPER LEVEL SUPPORT WINDS
WILL ALSO BE LIGHTER. OVERALL FOR MOST AREAS THIS WILL BE THE PICK
OF THE LABOR DAY WEEKEND FOR THE BEST WEATHER. SUNDAY NIGHT`S LOWS
WERE RAISED UP AS WELL SEVERAL DEGREES BASED ON THE LATEST GUIDANCE.
ENJOY THIS LITTLE BREAK FROM THE INTENSITY OF SUMMER.
.LONG TERM...MONDAY THROUGH SATURDAY.
THE MEDIUM RANGE MODELS INDICATE A GENERALLY DRY PATTERN FOR MOST OF
THE FORECAST AREA WITH A WARMING TREND THE SECOND HALF OF THE WEEK.
THERE IS SOME UNCERTAINTY WITH MOISTURE FORECASTS BETWEEN THE GFS
AND ECMWF BUT NEITHER SOLUTION DEPICTS SIGNIFICANT MOISTURE
SPREADING INTO THE AREA. THE GFS CONTINUES TO INDICATE LOW TO MID
LEVEL MOISTURE LINGERING OVER NORTHWEST ARIZONA THROUGH LABOR DAY
AND IT IS WORTH MENTIONING A SLIGHT CHANCE OF THUNDERSTORMS OVER THE
EASTERN HALF OF MOHAVE COUNTY. AN INCREASINGLY DRY WESTERLY FLOW
DEVELOPING TUESDAY SHOULD PUSH MOST OF THE MOISTURE TO THE EAST
TUESDAY BUT A SLIGHT CHANCE OF THUNDERSTORMS STILL EXISTS FOR THE
ARIZONA STRIP.
WE WILL NEED TO KEEP AN EYE ON ANOTHER TROPICAL SYSTEM NEAR SOUTHERN
BAJA WHICH THE MODELS INDICATE WILL DEVELOP AND MOVE TO THE WEST
NORTHWEST THOUGH THERE IS LITTLE CHANCE OF ANY SIGNIFICANT MOISTURE
BEING PULLED OUR WAY. THE WARMING TREND WILL COME DUE TO AN EASTERN
PACIFIC RIDGE MERGING WITH A RIDGE NEAR NORTHERN MEXICO EXPANDING TO
THE NORTHWEST AFTER WEDNESDAY. THE ECMWF SOLUTION IS A LITTLE WARMER
THAN THE GFS AND PROVIDES HIGH TEMPS SEVERAL DEGREES ABOVE NORMAL
WITH TRIPLE DIGIT READINGS BACK OVER MUCH OF THE MOJAVE DESERT
REGION FROM WEDNESDAY INTO NEXT WEEKEND.
&&
.AVIATION...FOR MCCARRAN...WINDS WILL AGAIN INCREASE LATE THIS
MORNING AND BE STRONGEST IN THE AFTERNOON AND EARLY EVENING GUSTING
OVER 20 KTS. THERE IS A SMALL WINDOW BETWEEN 14Z AND 17Z TODAY WHERE
WIND DIRECTION WILL BE NEAR THE 160 DEGREE LINE WHICH MAY CAUSE
CONFIGURATION ISSUES.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...THERE WILL AGAIN BE THE POSSIBILITY OF A SHRA/TSRA
TODAY AFTER 18Z AND BEFORE 06Z SUNDAY IN AND AROUND MT TRUMBILL. ALL
OTHER AREAS SHOULD BE DRY. OTHERWISE LOOK FOR SOUTH TO SOUTHWEST
WINDS INCREASING BETWEEN 16Z AND 20Z TODAY WITH GUSTS OF 20-30 KTS
EXCEPT IN LINCOLN COUNTY WHERE GUSTS TO AROUND 35 KTS ARE POSSIBLE.
WINDS WILL SLOWLY DECREASE BETWEEN 03Z AND 06Z SUNDAY. A CLEAR SKY
IS EXPECTED EXCEPT IN AREAS EAST AND NORTHEAST OF KIGM WHERE FEW-SCT
CLOUDS AOA 10K-15K FEET WILL BE AROUND IN THE AFTERNOON AND EARLY
EVENING.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
SHORT TERM/AVIATION...STACHELSKI
LONG TERM...ADAIR
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
544 PM MDT SUN SEP 6 2015
.AVIATION...
00Z TAF CYCLE
MOST CONVECTIVE ACTIVITY OVER THE FAR ERN PLAINS EARLY THIS
EVENING WITH A FEW SHOWERS/THUNDERSTORMS OVER WRN SOCORRO COUNTY.
VAST MAJORITY OF ACTIVITY WILL DIMINISH SHORTLY AFTER SUNSET WITH
ISOLD -TSRAS CONTINUE NEAR TX LINE UNTIL AROUND 06Z. SUBTROPICAL
MOISTURE IS FORECAST TO SURGE NWD INTO NM LATE TONIGHT AND MONDAY
MORNING. EXPECT A SIGNIFICANT UPSWING IN SHOWER AND THUNDERSTORM
ACTIVITY BEGINNING LATE MORNING MONDAY AND CONTINUING THROUGH THE
AFTERNOON. MTS OCCASIONALLY OBSCD IN MVFR CIGS/VSBYS WITH THE
STRONGER STORMS MONDAY AFTERNOON. SFC WND GUSTS TO 40KT POSSIBLE
AS WELL.
33
&&
.PREV DISCUSSION...318 PM MDT SUN SEP 6 2015...
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS WILL CONTINUE TO FAVOR AREAS SOUTH OF
I-40 THIS EVENING...BUT STORMS MAY EXPAND FARTHER NORTHWARD ON
MONDAY AFTERNOON. DRIER AIR WILL MOVE INTO THE STATE FROM THE
NORTHWEST ON TUESDAY AND WEDNESDAY...LIMITING STORMS ACROSS THE
NORTHWEST...BUT STORMS ACROSS THE EAST REMAIN POSSIBLE AS A BACK
DOOR COLD FRONT SLIDES SOUTHWARD. TEMPERATURES WILL RUN NEAR TO A
FEW DEGREES ABOVE NORMAL THROUGH AT LEAST THE MIDDLE OF THE WEEK.
FORECAST CONFIDENCE REMAINS LOW ESPECIALLY BEYOND MID WEEK AS
MODELS CONTINUE TO FLIP FLOP ON TIMING AND STRENGTH OF ANOTHER
BACK DOOR COLD FRONT.
&&
.DISCUSSION...
FORECAST CONFIDENCE FOR THE NEXT 7 DAYS IS QUITE LOW DUE TO MODEL
INCONSISTENCIES. HENCE...EXPECT CHANGES FROM THE FOLLOWING.
GENERALLY...THE UPPER HIGH THAT IS CENTERED OVER WEST TEXAS TODAY
WILL SLOWLY SHIFT SOUTH OF NM THROUGH TUESDAY...BEFORE ELONGATING
FROM NW TO SE ACROSS SOUTHERN AZ INTO OLD MEXICO. MEANWHILE...
TROPICAL STORM LINDA HAS FORMED SOUTH OF THE BAJA AND IS FORECAST
TO MOVE NW THRU THIS TIME PERIOD. IT DOES NOT APPEAR AT THIS TIME
THAT NM WILL BENEFIT FROM TS LINDAS MOISTURE...AS THE UPPER HIGH
WILL BE BLOCKING IT FROM REACHING US.
AS FOR THE DETAILS...THAT IS WHERE IT GETS MURKY. FOR
TONIGHT...THE HRRR SEEMS TO HAVE A PRETTY GOOD HANDLE ON CURRENT
CONVECTION. THUS...EXPECT THE STORMS ALONG THE SACS TO CONTINUE TO
MOVE NEWD THIS EVENING...AS WELL AS ALONG A WEAK CONVERGENCE ZONE
ACROSS THE EASTERN PLAINS. THE HRRR ALSO DEPICTS AN UPSWING IN
ACTIVITY AFTER MIDNIGHT TONIGHT ACROSS THE SW AND SC AREAS AS A
WEAK DISTURBANCE MOVES UP IN SSW FLOW. OTHER MODELS ARE NOT
TERRIBLY ENTHUSIASTIC ABOUT THIS FEATURE DURING THE OVERNIGHT
PERIOD...BUT IT MAY BE AT LEAST IN PART A REASON WHY THE NAM IS
BREAKING OUT MUCH MORE PRECIPITATION ON MONDAY THAN OTHER
MODELS...SPECIFICALLY ACROSS THE EAST AND NORTH. THE DEGREE OF
DRYING FOR MONDAY DEPICTED BY ANY MODEL ACROSS THE NORTH IS NOT
NEARLY AS STRONG AS IT WAS 24 OR 48 HOURS AGO DESPITE THE MORE
WESTERLY FLOW ALOFT. SO STANDS TO REASON THAT MONDAY WILL BE MORE
ACTIVE THAN TODAY...AND ALSO THAT THE NAM MAY BE ONTO SOMETHING.
HOWEVER...THE AMOUNT OF MID AND HIGH CLOUDS THAT MAY BE AROUND DUE
TO OVERNIGHT CONVECTION...IF THE HRRR IS RIGHT...MAY DIMINISH SOME
OF THE POTENTIAL INSTABILITY.
THE DRY AIR DOES APPEAR TO COME INTO AT LEAST THE NW AND PERHAPS
NC AREAS ON TUESDAY... WHICH SHOULD LIMIT CONVECTION THERE. THE
BACK DOOR FRONT THAT IS EXPECTED TO COME INTO THE NE LOOKS
STRONGER... AND MODELS ARE EVEN SHOWING AN INCREASE IN DEWPOINTS
ON TUESDAY AND TUESDAY NIGHT BEHIND THE FRONT. THEREFORE...HAVE
BUMPED UP POPS SLIGHTLY ACROSS THE SANGRES TO ACCOUNT FOR THE
MOIST UPSLOPE FLOW. THE FRONT DOES LOOK TO PUSH FURTHER SOUTH AND
WEST THAN WHAT MODELS SHOWED YESTERDAY...PERHAPS EVEN OOZING THRU
THE GAPS OF THE CENTRAL MTN CHAIN WED MORNING. WOULD EXPECT THE
CENTRAL MTN CHAIN TO HAVE A FAIR AMOUNT OF ACTIVITY ON WEDNESDAY
AFTERNOON WITH CONTINUED UPSLOPE FLOW AS THE WINDS SLOWLY VEER
AROUND TO THE EAST AND SOUTHEAST ACROSS THE PLAINS...BUT MODELS DO
NOT SHOW A CLEAR SIGNAL OF THAT. THIS IS LIKELY BECOMES OF THE
DRIER MID LEVEL AIR CONTINUING TO MOVE INTO THE NW HALF OF NM.
THUS...THE LOW LEVEL MOISTURE AND UPSLOPE FLOW WILL LIKELY HAVE A
FIGHT WITH THE STABILITY AT MID LEVELS.
THE STRONG FRONT THAT WAS SUPPOSED TO ARRIVE THURSDAY NIGHT AND
FRIDAY...WELL...APPARENTLY THE MODELS HAVE DECIDED THAT IS NOT
GOING TO HAPPEN. AFTER SHOWING THAT SCENARIO FOR SEVERAL MODEL
RUNS...BOTH THE LATEST EC AND GFS SHOW ONLY A WEAK WIND SHIFT
ACROSS THE NE. THUS POP CHANCES DURING THIS PERIOD AND THRU
SATURDAY HAVE BEEN TRIMMED CONSIDERABLY. BUT AS STATED AT THE
BEGINNING...CONFIDENCE IS QUITE LOW AND MODELS MAY YO-YO BACK
TOMORROW.
34
&&
.FIRE WEATHER...
ANOTHER RELATIVELY SLOW DAY FOR CONVECTION SO FAR. SOME DRIER AIR
HAS PUSHED INTO THE WEST AND CENTRAL IN THE MID LEVELS ALLOWING LOW
LEVEL MOISTURE TO MIX OUT. SHORT TERM MODELS STILL INDICATE LOCALES
SOUTH OF INTERSTATE 40 AND ALONG/EAST OF THE PECOS WILL HAVE THE
BEST CHANCES FOR WETTING RAIN TONIGHT. IN GENERAL...CELL MOVEMENT
WILL AGAIN BE TO THE NORTHEAST FOR THE REST OF THIS AFTERNOON AND
TONIGHT.
MONDAY FEATURES SOMEWHAT MORE WESTERLY WINDS...AND WITH HIGHER POPS
ALONG AND SOUTH OF INTERSTATE 40 AS THE TAP OF MOISTURE IS NOT
TOTALLY CUT OFF. OTHERWISE...CONFIDENCE IN THE TIMING OF FRONTS FOR
THIS WEEK IS AT AN ALL TIME LOW. THE STRONGER BOUNDARY...AND PUSH OF
LOW LEVEL MOISTURE WESTWARD...COULD NOW BE TUESDAY/WEDNESDAY AS THE
GFS CONTINUES TO DOWNPLAY THE FRIDAY/SATURDAY BOUNDARY. SO...THERE
WILL LIKELY BE A BOUNDARY OR MORE THIS WEEK IMPACTING ERN NM...AND
ACCOMPANIED BY SLOSHING OF LOW LEVEL MOISTURE WWD TO THE CENTRAL MT
CHAIN AND EVEN INTO THE RGV...BUT WHEN IT WILL HAPPEN THE MODELS
CAN/T...SO FAR...SEEM TO PREDICT CONSISTENTLY. THIS WILL IMPACT
CHANCES FOR WETTING RAIN TO AT LEAST SOME EXTENT...AND DAY TO DAY
CHANGES IN RH AND TEMPERATURES. CURRENT TRENDS THOUGH ARE FOR HIGHER
POPS TO SHIFT TO THE CENTRAL MT CHAIN/SOUTHEAST HALF OF THE FORECAST
AREA BY MIDWEEK...THEN DIMINISH OVERALL NEXT WEEKEND.
WHAT DOES APPEAR LESS VARIABLE IS ADDITIONAL DRYING OF WRN NM FROM
THE CONTDVD TO THE AZ BORDER. MID TO LATE WEEK...HIGH HAINES IS
FORECAST OVER THIS REGION AND LATE DAY DEW POINTS FALL INTO THE 30S
WITH EVEN SOME 20S THE FARTHER NORTH AND WEST YOU GO. CONSEQUENTLY
OVERNIGHT RH RECOVERIES LOOK TO BE FAIR TO EVEN POOR NORTHWEST BY
THURSDAY/FRIDAY NIGHT WHILE MIN RH VALUES FALL BELOW 15 PERCENT.
FORECAST VENT RATES MOSTLY GOOD TO EXCELLENT MONDAY/TUESDAY THEN
DECREASE SOME WEDNESDAY/THURSDAY WITH AREAS OF FAIR TO POOR CENTRAL
AND NORTH. FORECAST HIGHS WILL RUN WITHIN A FEW DEGREES OF AVERAGE
THRU WEDNESDAY/THURSDAY.
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
11
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
316 PM MDT SAT SEP 5 2015
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS WILL CONTINUE THIS EVENING FAVORING THE
WESTERN TWO-THIRDS OF NEW MEXICO. A FEW STORMS MAY BRIEFING BECOME
STRONG WITH HEAVY RAIN AND SMALL HAIL. STARTING SUNDAY AND
CONTINUING INTO THE MIDDLE OF THE WEEK...A DRYING TREND WILL BE
IN STORE ACROSS AT LEAST THE NORTHERN HALF OF THE STATE. THIS WILL
GENERALLY CONFINE STORMS TO AREAS SOUTH OF INTERSTATE 40. ONE
EXCEPTION WILL BE A BACK DOOR FRONT THAT ARRIVES ON TUESDAY WHICH
MAY SPARK A FEW STORMS ACROSS NORTHEAST NEW MEXICO. A STRONGER
BACK DOOR FRONT LOOKS TO ARRIVE THURSDAY INTO FRIDAY...
SIGNIFICANTLY INCREASING STORM CHANCES...INITIALLY ACROSS EASTERN
NEW MEXICO...BUT EVENTUALLY ACROSS CENTRAL AND WESTERN NEW MEXICO
AS WELL.
&&
.DISCUSSION...
MID AND HIGH LEVEL CLOUDS CONTINUE TO INHIBIT INSTABILITY ACROSS
MUCH OF WESTERN NM...SIMILAR TO YESTERDAY...THANKS TO THE FORMER
TS KEVIN. HOWEVER...CLOUDS ARE BEGINNING TO THIN...AND WHERE THERE
ARE ENOUGH BREAKS IN THE CLOUDS FOR SOME INSOLATION...TSTMS HAVE
DEVELOPED. THE STRONGEST THUS FAR HAS BEEN BETWEEN NAVAJO DAM AND
DULCE...WHICH LIKELY PRODUCED SOME SMALL HAIL. FOR THE REST OF THE
EVENING...STORMS SHOULD CONTINUE THRU AT LEAST SUNSET...AND
QUICKLY DIMINISH IN COVERAGE THEREAFTER. LARGELY WENT WITH THE
HRRR FOR THE POP FORECAST TONIGHT...WHICH PLACES MUCH OF THE QPF
ACROSS THE NORTHERN MTNS AS A WEAK VORT MAX QUICKLY MOVES THRU THE
SW FLOW.
STILL LOOKS TO BE A FAIR AMOUNT OF CLOUD COVER ON SUNDAY...
DESPITE THE PLUME BECOMING LESS ORGANIZED. HOWEVER...THE CLOUD
COVER LOOKS LIKE IT MAY BE DISPLACED A BIT EASTWARD FROM WHERE IT
WAS LARGELY LOCATED TODAY. IF THIS IS THE CASE...A BIT MORE
CONVECTION WILL BE POSSIBLE FOR WESTERN NM.
DRIER MID LEVEL AIR STILL LOOKS LIKE IT WILL MOVE INTO NORTHERN
NM ON MONDAY...LIMITING CONVECTION A BIT MORE THAN ON SUNDAY
PERHAPS. HOWEVER...THOUGH THE GFS AND EC AGREE ON THIS...THE NAM
IS QUITE BULLISH AT BREAKING OUT PRECIP ACROSS MUCH OF THE EASTERN
TWO-THIRDS OF THE FORECAST AREA AS ANOTHER WEAK VORT MAX CROSSES
THE AREA. INCREASED POPS A BIT...BUT WOULD LIKE TO SEE MORE MODEL
CONSISTENCY BEFORE INCREASING POPS MUCH FURTHER.
MID LEVEL DRY AIR CONTINUES TO MOVE IN TO NW NM ON TUESDAY AS THE
UPPER CENTERS ITSELF SOUTH OF THE STATE ALLOWING FOR MORE WESTERLY
FLOW OVER NM. THIS SHOULD AGAIN KEEP THE HIGHEST CHANCES FOR
PRECIP SOUTH OF I-40...HOWEVER A BACK DOOR COLD FRONT WILL NUDGE
INTO NE NM WHICH MAY SPARK A FEW STORMS IF THE MID LEVEL DRYING IS
NOT OVERWHELMING.
DRIER CONDITIONS WILL PERSIST ACROSS MUCH OF WESTERN AND EVEN
PORTIONS OF CENTRAL NM WED AND THURS WHILE ACROSS THE EAST...AS
THE FRONT WASHES OUT...SOME GULF MOSITRUE SHOULD BE PULLED INTO
THE EASTERN PLAINS. A STRONGER BACK DOOR FRONT LOOKS TO ARRIVE
AROUND THE THURS NIGHT TIME FRAME...WHICH BOTH THE EC AND GFS
SUGGEST COULD BRING SOME DECENT QPF TO AT LEAST EASTERN NM. THE
FRONT LOOKS TO PUSH THRU THE GAPS OF THE CENTRAL MTN CHAIN THURS
NIGHT/FRI MORNING...SETTING THE STAGE FOR A GREATER COVERAGE OF
TSTMS DURING FRIDAY/SATURDAY PERIOD.
34
&&
.FIRE WEATHER...
LITTLE CHANGE IN THE OVERALL PATTERN TODAY WITH A STREAM OF MOISTURE
PERSISTING OVER NEW MEXICO. EXTENSIVE CLOUD COVER FRIDAY HAS THINNED
OUT TODAY...WITH SOMEWHAT BETTER HEATING AND POTENTIAL FOR STORMS
WEST AND CENTRAL...THOUGH FOR THE MOST PART...EXISTING STORMS
APPEAR TO BE STRUGGLING. CELLS WILL MOVE TO THE NORTHEAST AT A GOOD
RATE...AROUND 25 MPH.
WHILE AREAS ALONG AND NEAR THE CONTDVD AS WELL AS THE NORTH CENTRAL
MAY BE FAVORED FOR WETTING RAIN TONIGHT...THE HRRR IS NOW ONBOARD
WITH A LINE OF CONVECTION ALONG THE EAST SLOPES OF THE CENTRAL MT
CHAIN...WHICH PROGRESSES EASTWARD INTO THE PLAINS LATE THIS
AFTERNOON/EARLY THIS EVENING BEFORE DIMINISHING. CURRENT SATELLITE
TRENDS SUPPORT THIS IDEA.
MODELS CONTINUE TO BACK OFF ON THE ANTICIPATED DRYING FOR
SUNDAY/MONDAY. THE MAIN UPPER LOW MOVES EAST OVER THE NRN
ROCKIES...LEAVING A WEAK TROUGH BEHIND AND TO OUR WEST...WHICH KEEPS
AT LEAST SOME MOISTURE FLOWING INTO NM. THE HIGHER POPS WILL FAVOR
LOCALES ALONG AND SOUTH OF INTERSTATE 40. A WEAK WIND SHIFT IS STILL
ON TAP FOR SUNDAY IN THE NORTHEAST BUT IT/S INCONSEQUENTIAL. A
SOMEWHAT STRONGER BOUNDARY WILL IMPACT THE NORTHEAST TUESDAY...AND
YET ANOTHER STRONGER ONE THURSDAY NIGHT/FRIDAY. TIMING ON THE MID TO
LATE WEEK FRONTS HAS BEEN PROBLEMATIC AND EXPECT THERE WILL BE
CHANGES. AREAS ALONG THE CONTDVD AND WWD WILL SEE DEW POINTS DRY OUT
AS THE WEEK PROGRESSES AND WHERE HIGH HAINES IS FORECAST LATE NEXT
WEEK...BUT THE FRONTS WILL REPLENISH LOW LEVEL MOISTURE EAST AND
CENTRAL...WHERE CHANCES FOR WETTING RAIN INCREASE FRIDAY/FRIDAY
NIGHT.
MIN RH VALUES COULD FALL BELOW 15 PERCENT LATE NEXT WEEK FAR
NORTHWEST...AND WILL BE COMBINED WITH FAIR TO POOR OVERNIGHT
RECOVERIES. OVERNIGHT RECOVERIES MAY ONLY BE FAIR FOR SOME OF THE
LOWER TERRAIN CENTRAL AND WEST NEXT TUESDAY AND WEDNESDAY NIGHTS.
HIGHS WILL RUN WITHIN A FEW DEGREES OF AVERAGE FOR MOST OF NEXT
WEEK.
VENT RATES WILL BE MOSTLY GOOD SUNDAY AND MONDAY WITH SOME POCKETS
OF FAIR TO POOR CENTRAL AND WEST. THERE IS SLIGHT IMPROVEMENT
OVERALL TUESDAY AND WEDNESDAY...BUT SOME AREAS OF FAIR TO POOR EAST
WEDNESDAY.
&&
.AVIATION...
18Z TAF CYCLE
UPPER TROF TO THE WEST CONTINUING TO PULL MOISTURE OVR NM WITH
RELATIVELY STRONG SW WINDS ALF AOA MT TOP LEVELS. MTS BECOMING
OCCASIONALLY OBSCURED IN SCT CONVECTION WITH SOME MVFR CIGS/VSBYS
IN STRONGER STORMS. POTENTIAL FOR WIND GUSTS TO 40KT. STORM MOTION
WOULD PERMIT CONVECTION TO MOVE OFF THE CENTRAL MT CHAIN AND INTO
THE ERN PLAINS BUT SHORT TERM MODELS NOT ENTHUSED ABOUT THIS UNTIL
AFT 03Z WHEN HRRR/RAP MOVES A CLUSTER INTO THE NE
HIGHLANDS/PLAINS.
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 56 83 57 85 / 40 5 10 10
DULCE........................... 45 76 45 77 / 60 20 20 10
CUBA............................ 50 75 50 77 / 50 20 20 20
GALLUP.......................... 48 80 50 81 / 40 20 20 20
EL MORRO........................ 48 75 49 77 / 50 30 30 30
GRANTS.......................... 50 79 50 80 / 50 20 20 20
QUEMADO......................... 53 76 54 77 / 40 30 30 30
GLENWOOD........................ 56 80 56 84 / 30 20 20 30
CHAMA........................... 46 73 45 75 / 60 20 20 20
LOS ALAMOS...................... 56 78 58 79 / 50 10 20 20
PECOS........................... 54 77 55 79 / 30 10 10 20
CERRO/QUESTA.................... 51 76 51 77 / 50 10 10 10
RED RIVER....................... 43 68 41 70 / 60 20 20 20
ANGEL FIRE...................... 48 70 47 72 / 50 20 20 20
TAOS............................ 50 78 47 80 / 50 10 10 10
MORA............................ 52 74 51 77 / 30 20 20 20
ESPANOLA........................ 54 83 53 84 / 50 5 10 10
SANTA FE........................ 58 78 58 82 / 50 10 10 10
SANTA FE AIRPORT................ 56 82 56 85 / 50 10 10 10
ALBUQUERQUE FOOTHILLS........... 61 83 62 84 / 50 5 10 20
ALBUQUERQUE HEIGHTS............. 62 84 64 85 / 50 5 10 10
ALBUQUERQUE VALLEY.............. 60 86 61 87 / 50 5 10 10
ALBUQUERQUE WEST MESA........... 61 84 63 85 / 50 5 10 10
LOS LUNAS....................... 58 86 59 87 / 50 5 10 10
RIO RANCHO...................... 62 85 62 86 / 50 5 10 10
SOCORRO......................... 62 86 63 88 / 30 20 20 30
SANDIA PARK/CEDAR CREST......... 56 78 57 82 / 50 10 10 20
TIJERAS......................... 58 81 59 83 / 40 5 10 20
MORIARTY/ESTANCIA............... 52 81 52 84 / 20 10 10 20
CLINES CORNERS.................. 55 79 56 81 / 20 20 20 30
GRAN QUIVIRA.................... 58 81 59 81 / 30 20 20 30
CARRIZOZO....................... 62 84 62 84 / 30 10 20 20
RUIDOSO......................... 58 77 58 78 / 30 30 40 40
CAPULIN......................... 56 81 54 84 / 20 10 10 5
RATON........................... 53 84 52 86 / 30 10 10 10
SPRINGER........................ 54 85 54 87 / 20 10 10 10
LAS VEGAS....................... 54 81 54 83 / 20 10 10 20
CLAYTON......................... 63 89 63 91 / 20 10 10 20
ROY............................. 59 85 58 87 / 20 10 10 20
CONCHAS......................... 66 92 65 93 / 20 10 10 20
SANTA ROSA...................... 64 90 65 91 / 30 10 10 30
TUCUMCARI....................... 66 94 66 95 / 20 10 10 30
CLOVIS.......................... 64 91 64 92 / 10 20 20 30
PORTALES........................ 67 92 65 92 / 10 20 20 30
FORT SUMNER..................... 66 91 66 92 / 20 10 20 30
ROSWELL......................... 68 94 68 94 / 20 20 20 30
PICACHO......................... 62 88 63 88 / 20 20 20 30
ELK............................. 61 82 61 82 / 30 30 40 30
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
34
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1008 PM EDT SUN SEP 6 2015
.SYNOPSIS...AN UPPER LEVEL LOW WILL RETROGRADE FROM GA TO THE
NORTHERN GULF OF MEXICO TONIGHT...THEN STALL NEAR THE TEXAS GULF
COAST THROUGH MID-WEEK. SURFACE HIGH PRESSURE WILL OTHERWISE WEAKEN
WHILE EXTENDING WEST INTO NC.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1005 PM SUNDAY...
A MID-UPPER LOW OVER GA WILL DRIFT SW AND AWAY FROM CENTRAL NC
TONIGHT...WHILE 1022 MB SURFACE HIGH PRESSURE OFFSHORE THE MIDDLE
ATLANTIC COAST CONTINUES TO EXTEND SW INTO NC. THE AIR MASS OVER
CENTRAL NC IS A STABLE ONE PER 00Z GSO RAOB DATA AND MORE RECENT SPC
MESOANALYSIS DATA. GIVEN THE STABILITY AND LACK OF FORCING FOR
ASCENT...EXCEPT MOISTURE TRANSPORT AND FRICTIONAL CONVERGENCE ALONG
SOUTHEASTERN NC...DRY CONDITIONS ARE EXPECTED OVERNIGHT.
BOTH THE HRRR AND SREF SUGGEST LOW CLOUDS ARE LIKELY TO ADVECT/
DEVELOP SOUTHWESTWARD INTO THE WESTERN HALF OR TWO THIRDS OF THE
FORECAST AREA TONIGHT...WHICH SEEMS REASONABLE GIVEN A RELATIVE LACK
OF LOW CLOUD COVER UPSTREAM IN SE VA AND NE NC...WHERE NWP GUIDANCE
SUGGESTS A TONGUE OF DRY AIR WILL EXTEND...AND LATER DRIFT INTO THE
COASTAL PLAIN.
&&
.SHORT TERM /MONDAY AND MONDAY NIGHT/...
AS OF 300 PM SUNDAY...
THE UPPER LOW IS PROGGED TO BE LOCATED ACROSS THE NORTHEASTERN GULF
OF MEXICO BY 12Z MONDAY...BEFORE RETROGRADING EVEN FURTHER TOWARDS
THE NORTHWESTERN GULF THROUGHOUT THE DAY. AS A RESULT...ANY WEAK
DISTURBANCES THAT ROUND THE EASTERN/NORTHERN PERIPHERY OF THE LOW
SHOULD REMAIN SOUTH/SOUTHWEST OF CENTRAL NC. THEREFORE...CONVECTION
IS EXPECTED TO BE RATHER LIMITED...OUTSIDE OF ANY DIURNAL ACTIVITY.
HIGH TEMPS SHOULD BE SLIGHTLY WARMER GIVEN LESS CLOUDS/PRECIP...
GENERALLY MID/UPPER 80S AND OVERNIGHT LOWS WILL BE SIMILAR TO
PREVIOUS NIGHTS...WITH UPPER 60S TO NEAR 70 DEGREES EXPECTED.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
AS OF 245 PM SUNDAY...
CONTINUED RETROGRESSION OF CUTOFF UPPER LOW TO THE SOUTHWEST OPENS
THE DOOR FOR DEEPER MOISTURE ADVECTION AS AN UPPER TROF DIGS INTO
THE MIDWEST. MEANWHILE...A WEAK SURFACE FRONT WILL BE STALLING OVER
THE AREA WEDNESDAY THROUGH FRIDAY...CONCURRENT WITH PRECIPITABLE
WATER INCREASING FROM <1.5 INCHES TUESDAY TO 1.75-2 INCHES WEDNESDAY
THROUGH FRIDAY. UPPER DYNAMICS ARE NOT PARTICULARLY INVITING FOR
CONVECTION EARLY IN THE PERIOD...BUT WOULD EXPECT TO SEE MORE
COVERAGE AND ORGANIZATION FRIDAY WHEN THE UPPER TROF SHIFTS FAR
ENOUGH EAST TO TIGHTEN UP THE GRADIENTS ASSOCIATED WITH THE STALLED
SURFACE FRONT AS WELL AS INCREASING UPPER JET DIFFLUENCE AND
ENHANCING UPDRAFT POTENTIAL. WILL MAINTAIN POPS IN THE USUAL DIURNAL
PATTERN FROM THE LOW CHANCE CATEGORY TUESDAY INCREASING TO 50% BY
FRIDAY. HIGHS WILL BE AT OR SOMEWHAT ABOVE NORMAL...MID TO UPPER 80S
THROUGH FRIDAY AFTER MORNING LOWS MOSTLY FROM 65 TO 70.
THE UPPER TROF LIFTS OUT AFTER IT HAS NUDGED THE SURFACE FRONT
SOUTHEAST OF THE AREA...WHICH WILL PROVIDE US WITH DRYING AND SOME
WELCOME COOLING FOR THE WEEKEND. HIGHS SHOULD RANGE FROM UPPER 70S
TO LOWER 80S BOTH DAYS WITH SMALL CHANCE POPS MAINLY IN THE
SOUTHEAST.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
AS OF 803 PM SUNDAY...
A BROKEN LINE OF SHOWERS AND STORMS HAS MOVED THROUGH KFAY AND
KRWI... AND IS WEAKENING AS IT MOVES WESTWARD. SUB-VFR STRATUS IS
LIKELY TO DEVELOP ACROSS THE AREA TONIGHT AS WE REMAIN UNDER THE
INFLUENCE OF A MOIST NORTHEASTERLY FLOW. VFR CONDITIONS WILL TO
RETURN MONDAY AFTERNOON.
OUTLOOK...AN UNSETTLED PATTERN WILL PERSIST THROUGH THE PERIOD WITH
ABOVE NORMAL CHANCES FOR CONVECTION (ESPECIALLY LATE IN THE WEEK) IN
ADDITION TO MORNING STRATUS OR FOG.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...26
NEAR TERM...26
SHORT TERM...KRD
LONG TERM...MLM
AVIATION...30/KRD
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
245 PM EDT SAT SEP 5 2015
.SYNOPSIS...
WETTER AND SLIGHTLY COOLER WEATHER IS EXPECTED THE NEXT FEW DAYS
AS HIGH PRESSURE PUSHING FROM THE NORTH COMBINES WITH DEEP AND
MOIST WINDS OFF THE ATLANTIC. A WARMING TREND WITH A DECREASE IN
RAIN CHANCES IS EXPECTED TUESDAY THROUGH MID-WEEK. A COLD FRONT
WILL APPROACH LATE IN THE WEEK AND MAY STALL ALONG THE COAST NEXT
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 245 PM SATURDAY...THE NORTHEAST FLOW CONTINUES ACROSS THE
REGION THIS AFTERNOON AND WILL MAINTAIN THIS PATTERN THROUGH
SUNDAY MORNING. SHALLOW CONVECTION DEVELOPING TO THE NORTH AND
EXPECT SOME ISOLATED ACTIVITY TO MEANDER INTO AND OR DEVELOP
ACROSS OUR AREA THIS AFTERNOON. COVERAGE SHOULD BE LIMITED AS THE
AFFECTS OF A DRY TONGUE AROUND 800MB SLOWLY ABATE. THE LIMITED
CONVECTION IS MOSTLY DIURNALLY DRIVEN AND HAVE DECREASED POPS FOR
THE OVERNIGHT HOURS WHILE NOT REMOVING ENTIRELY. WITH LITTLE TO NO
DECOUPLING EXPECTED...I PEGGED LOWS AT A DEGREE OR TWO ABOVE
GUIDANCE. SHOULD SEE UPPER 60S TO LOWER 70S.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 245 PM SATURDAY...PRIME WEATHER CAPTION THIS PERIOD REMAINS
ELEVATED RAIN CHANCES AND EARLY FALL LIKE DAYTIME TEMPERATURES.
SURFACE HIGH PRESSURE IN WEDGE FASHION WILL PRESS FROM THE NORTH
WHILE THE COLUMN UNDERGOES A DEEP AND MOIST ONSHORE FLOW OFF THE
WESTERN ATLANTIC. H7-H5 VORTICITY DEPICTIONS OVERLAID WITH PCPN
FIELDS SHOW A CYCLONIC UPPER CIRCULATION OFFSHORE OF JAX FLORIDA
ALONG 30N DIRECTING IMPULSES ALOFT INTO COASTAL NE SC AND SE NC
SUNDAY AND MONDAY. TIME HEIGHT PLOTS SHOW LIGHT COLUMN WINDS AND
STEERING FLOW THIS PERIOD WITH HIGH PRECIPITABLE WATERS...WHICH WILL
LEND TO A POTENTIAL FOR LOCALIZED FLOODING BENEATH AND NEAR STOUT
CELLS. DAYTIME HIGHS ARE SETTING UP TO RUN NEAR OR BELOW NORMAL FOR
VERY EARLY SEPTEMBER DUE TO CLOUDS AND RAIN-COOLED AIR. THE WEDGE
WILL LIKELY MEAN LESS RAINFALL INLAND COMPARED TO THE COAST...AND
WPC SUNDAY/MONDAY QPF FORECASTS SHOW UP TO AN INCH NEAR THE COAST
TAPERING TO LESS THAN A QUARTER INCH NEAR AND WEST OF I-95. BECAUSE
OF CLOUDS AND MOISTURE RICH AIR...MINIMUMS MAY RUN A BIT ABOVE
NORMAL EARLY ON MONDAY AND TUESDAY...VERY UPPER 60S INLAND AND LOW
TO MIDDLE 70S NEAR THE COAST.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 245 PM SATURDAY...THERE MAY BE A LITTLE BAGGINESS IN THE
MID LEVEL HEIGHT FIELD TO OUR WEST ON TUESDAY IN ASSOC WITH THE
RETROGRADING AND WEAKENING TROUGH TO SUPPORT SLIGHTLY ELEVATED
POPS. THE SEA BREEZE WILL ALSO MAKE A CONTRIBUTION TO THE COVERAGE
OF CONVECTION WHILE TEMPERATURES HANG CLOSE TO SEASONABLE NORMS.
WESTERLY MID LEVEL FLOW RETURNS ON WEDNESDAY WHILE THE SURFACE
FLOW REMAINS WEAK AS THE BERMUDA HIGH HAS TROUBLE REASSERTING
ITSELF. ISOLATED CONVECTION REMAINS POSSIBLE HOWEVER WITH THE SEA
BREEZE AND ONLY WEAK CAPPING. MUCH OF THIS WILL HOLD TRUE ON
THURSDAY THOUGH A PIEDMONT TROUGH WILL CREATE SOME LOW LEVEL
STEERING FOR THE SEA BREEZE IN ADDITION TO YIELDING ITS OWN
ISOLATED CONVECTION. MOISTURE SHOULD DEEPEN ON FRIDAY AS MID LEVEL
FLOW BACKS IN RESPONSE TO DEEP TROUGH DIGGING INTO THE GREAT
LAKES. THIS UPPER SYSTEM DRIVES WHAT MAY BE A STRONG COLD FRONT
INTO THE REGION COME SATURDAY.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 18Z...HIGH PRESSURE WILL CONTINUE TO RIDGE INTO THE REGION
THROUGH THE AFTERNOON HOURS WITH ONLY A SLIGHT CHANCE FOR
SHOWERS...MAINLY INLAND. THE LATEST HRRR MODEL CONFIRMS THIS WITH
ONLY ISOLATED CONVECTION THROUGH THE AFTERNOON HOURS ALONG THE
RESULTANT AND POINTS WEST. LIGHT NORTHEAST FLOW WILL CONTINUE THIS
EVENING. THERE IS A MODERATE RISK FOR MVFR/IFR CONDITIONS TOWARD
MORNING WITH THE WEDGE IN PLACE. MAINLY A MVFR CEILING FOR SUNDAY
WITH SCATTERED CONVECTION POSSIBLE.
EXTENDED OUTLOOK...PREDOMINATELY VFR WITH BRIEF MVFR AND POSSIBLY
IFR...IN MORNING FOG...AND ISOLATED/SCATTERED AFTERNOON EARLY
EVENING SHOWERS AND THUNDERSTORMS THROUGH THE EXTENDED.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 245 PM SATURDAY...WINDS FAIRLY STEADY AT JUST UNDER 15
KNOTS AT JMPN7 WITH SLIGHTLY HIGHER VALUES FOR 41013 AT THIS HOUR.
12 UTC GUIDANCE SHOWS A BRIEF SURGE MOVING THROUGH AT 925MB WHICH
IS KICKING UP WINDS A BIT MORE THAN EXPECTED. A BRIEF 15-20 KNOT
RANGE SHOULD COVER THE NC ZONES THIS AFTERNOON WHILE ALL WATERS
SETTLE INTO A 10-15 KNOT RANGE THIS EVENING AND OVERNIGHT. THE
SWAN MODEL HAS INITIALIZED SEAS WELL WITH FOUR FOOTERS ACROSS THE
OUTER WATERS. THE TREND ALONG WITH THE WINDS SHOULD BE DOWN THIS
EVENING AND OVERNIGHT SETTLING INTO A 2-3 FOOT RANGE.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 245 PM SATURDAY...10-15 KT NE-ENE WINDS WILL KEEP SEAS A
MODERATELY BUMPY 3 FOOT MOST AREAS...EXCEPT 2 FEET OR LESS IN
THE PROTECTED LOCATIONS OFF THE BRUNSWICK COAST FROM NE WIND.
BY TUESDAY WINDS WILL VEER TO E-SE AS HIGH PRESSURE WEAKENS OVER
THE AREA. SCATTERED SHOWERS AND ISOLATED TSTMS CAN BE EXPECTED
OVER THE WATERS THIS PERIOD AS SEVERAL WEAK DISTURBANCES ALOFT
MOVE ONSHORE SUNDAY AND MONDAY. VSBYS COULD BE LIMITED AT TIMES
IN RAIN TO 2 NM. SEAS 3 FEET IN ESE WAVES 2 FEET EVERY 9 SECONDS
AND NE-E WAVES 1-2 FEET EVERY 4-5 SECONDS.
LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 245 PM SATURDAY...THE GRADIENT WILL BE POORLY DEFINED ON
TUESDAY LEADING TO A LIGHT AND SOMEWHAT VARIABLE WIND AT LEAST
INITIALLY. AS THE DAY WEARS ON A RATHER SEASONABLY NORMAL SOUTHERLY
COMPONENT WILL BECOME ESTABLISHED EVEN AS SPEEDS REMAIN BELOW 10 KT.
AN EASTERLY SWELL COMPONENT OF 10-11 SECONDS WILL COMBINE WITH THE
MINIMAL WIND WAVES FOR A 2 FT SEAS FORECAST. SOUTH TO SOUTHWEST FLOW
MAY INCREASE 5 FT ON WEDNESDAY SEEMINGLY DUE TO SLIGHTLY HIGHER
WINDS ALOFT RATHER THAN ANY REAL INCREASE OR CHANGE IN THE SURFACE
PRESSURE PATTERN. A PIEDMONT TROUGH ON THE OTHER HAND WILL KEEP US
LOCKED INTO A 10-15KT SOUTHWESTERLY FLOW. EACH DAY WILL SEE A
NEARSHORE SEABREEZE VEER IN WIND DIRECTION.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MJC
NEAR TERM...SHK
SHORT TERM...MJC
LONG TERM...MBB
AVIATION...DL/SHK
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
122 PM EDT SAT SEP 5 2015
.SYNOPSIS...
HIGH PRESSURE WILL RIDGE DOWN FROM NEW ENGLAND TODAY BRINGING
COOLER TEMPERATURES. THIS HIGH PRESSURE WILL PERSIST INTO EARLY
NEXT WEEK CONTINUING SOMEWHAT BELOW NORMAL TEMPERATURES...BUT WITH
INCREASING CHANCES FOR SHOWERS. A RETURN TO MORE TYPICAL LATE
SUMMER WEATHER WILL DEVELOP TUESDAY AND PERSIST THROUGH THE END OF
THE WEEK. A COLD FRONT WILL APPROACH BY NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 125 PM SATURDAY...THE NORTHEAST FLOW CONTINUES ACROSS THE REGION
THIS AFTERNOON AND WILL MAINTAIN THIS PATTERN THROUGH SUNDAY
MORNING. SHALLOW CONVECTION DEVELOPING TO THE NORTH AND EXPECT
SOME ISOLATED ACTIVITY TO MEANDER INTO AND OR DEVELOP ACROSS OUR
AREA THIS AFTERNOON. COVERAGE SHOULD BE LIMITED AS THE AFFECTS OF
A DRY TONGUE AROUND 800MB SLOWLY ABATE. THE LIMITED CONVECTION IS
MOSTLY DIURANNALY DRIVEN AND HAVE DECREASED POPS FOR THE OVERNIGHT
HOURS WHILE NOT REMOVING ENTIRELY. WITH LITTLE TO NO DECOUPLING
EXPECTED...I PEGGED LOWS AT A DEGREE OR TWO ABOVE GUIDANCE. SHOULD
SEE UPPER 60S TO LOWER 70S.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SATURDAY...UPPER TROUGH WILL CLOSE OFF AND BE FORCED TO
RETROGRADE FROM THE WESTERN ATLANTIC OCEAN BACK ACROSS THE SOUTHEAST
THIS PERIOD AS LARGE RIDGING BLOCKS ITS PROGRESSION TO THE NORTH OR
EAST. BENEATH THIS FEATURE...A SURFACE TROUGH WILL ALSO BACK IN FROM
THE ATLANTIC AND INTO THE CAROLINAS SUNDAY INTO MONDAY...ALONG WITH
HIGHER PRECIPITABLE WATERS FROM REMNANT TROPICAL MOISTURE POOLED
FROM EX-TROPICAL STORM ERIKA. ALL OF THESE FEATURES TOGETHER WILL
CREATE A GOOD CHANCE FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY
DURING THE AFTNS WHEN HEATING OF THE DAY WILL HELP TRIGGER
CONVECTION ALONG THE SURFACE TROUGH. HOWEVER...AT LEAST SCHC POP
WILL BE CARRIED EVEN AT NIGHT DUE TO HIGH COLUMN MOISTURE...THE
SURFACE FEATURE...AND RELATIVELY STEEPER LAPSE RATES THANKS TO THE
500MB TROUGH OVERHEAD.
TEMPS BOTH DAYS WILL LIKELY FEATURE LOW DIURNAL RANGES AS CLOUD
COVER AND PRECIP KEEPS MINS ABOVE NORMAL AND HIGHS BELOW. EXPECT
LOWS EACH NIGHT TO DROP TO 68-72...WARMEST AT THE COAST...WITH
HIGHS IN THE LOW 80S AT THE COAST...MID 80S WELL INLAND.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 300 AM SATURDAY...UPPER TROUGH PLAGUING THE SOUTHEAST THE
SEVERAL DAYS LEADING UP TO THIS PERIOD WILL SLOWLY FILL AND
DISSIPATE BY MID-WEEK AS RIDGING DEVELOPS NEAR FLORIDA AND EXPANDS
TO THE NORTH. WHILE OVERALL THICKNESS INCREASE WILL BE
MARGINAL...THE EROSION OF THE SURFACE TROUGH ASSOCIATED WITH THE
BUILDING HEIGHTS COMBINED WITH BERMUDA-TYPE RIDGING WILL BRING DRIER
AND WARMER CONDITIONS MUCH OF NEXT WEEK. TUESDAY MAY STILL FEATURE
ABOVE-CLIMO PRECIP CHANCES AS IT IS THE TRANSITION DAY...BUT WED-FRI
WILL BE MORE SUMMER-LIKE WITH TYPICAL DIURNAL CONVECTIVE CHANCES AND
TEMPS SEVERAL DEGREES ABOVE CLIMO FOR BOTH HIGHS AND LOWS. A COLD
FRONT WILL APPROACH LATE IN THE PERIOD BUT FOR NOW WILL KEEP IT JUST
NW OF THE AREA UNTIL THE WEEKEND.
&&
.AVIATION /17Z SATURDAY THROUGH WEDNESDAY/...
AS OF 18Z...HIGH PRESSURE WILL CONTINUE TO RIDGE INTO THE REGION
THROUGH THE AFTERNOON HOURS WITH ONLY A SLIGHT CHANCE FOR
SHOWERS...MAINLY INLAND. THE LATEST HRRR MODEL CONFIRMS THIS WITH
ONLY ISOLATED CONVECTION THROUGH THE AFTERNOON HOURS ALONG THE
RESULTANT AND POINTS WEST. LIGHT NORTHEAST FLOW WILL CONTINUE THIS
EVENING. THERE IS A MODERATE RISK FOR MVFR/IFR CONDITIONS TOWARD
MORNING WITH THE WEDGE IN PLACE. MAINLY A MVFR CEILING FOR SUNDAY
WITH SCATTERED CONVECTION POSSIBLE.
EXTENDED OUTLOOK...PREDOMINATELY VFR WITH BRIEF MVFR AND POSSIBLY
IFR...IN MORNING FOG...AND ISOLATED/SCATTERED AFTERNOON EARLY
EVENING SHOWERS AND THUNDERSTORMS THROUGH THE EXTENDED.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 125 PM SATURDAY...WINDS FAIRLY STEADY AT JUST UNDER 15 KNOTS AT
JMPN7 WITH SLIGHTLY HIGHER VALUES FOR 41013 AT THIS HOUR. 12 UTC
GUIDANCE SHOWS A BRIEF SURGE MOVING THROUGH AT 925MB WHICH IS
KICKING UP WINDS A BIT MORE THAN EXPECTED. A BRIEF 15-20 KNOT RANGE
SHOULD COVER THE NC ZONES THIS AFTERNOON WHILE ALL WATERS SETTLE
INTO A 10-15 KNOT RANGE THIS EVENING AND OVERNIGHT. THE SWAN MODEL
HAS INITIALIZED SEAS WELL WITH FOUR FOOTERS ACROSS TEH OUTER WATERS.
THE TREND ALONG WITH THE WINDS SHOULD BE DOWN THIS EVENING AND
OVERNIGHT SETTLING INTO A 2-3 FOOT RANGE.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM FRIDAY...SURFACE RIDGE OF HIGH PRESSURE WILL BUILD DOWN
THE COAST THROUGH THE SHORT TERM...WHILE A COASTAL TROUGH PUSHES
SLOWLY INLAND BENEATH A MID-LEVEL TROUGH. THIS WILL MAINTAIN NE
WINDS SUNDAY AND MUCH OF MONDAY...WITH SLIGHT VEERING TO MORE
EASTERLY WINDS LATE MONDAY AS THE SURFACE TROUGH PUSHES INLAND.
HIGHEST SPEEDS THIS PERIOD WILL BE SUNDAY WHEN THE RIDGE IS
STRONGEST AND THE GRADIENT IS PINCHED...AS WINDS REACH 15-20 KTS
BEFORE FALLING BACK TO 10-15 KTS BY MONDAY...AND THEN BELOW 10 KTS
MONDAY NIGHT. THE SEA SPECTRUM WILL BE DOMINATED BY A 5-6 SEC NE
WIND WAVE WHICH WILL EASE AND LENGTHEN INTO MONDAY...CREATING 3-4 FT
SEAS SUNDAY...DROPPING TO 1-3 FT ON MONDAY.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 300 AM SATURDAY...HIGH PRESSURE EXPANDING OFF THE FLORIDA
COAST WILL DRIVE A RETURN TO MORE TYPICAL SUMMERTIME CONDITIONS
THROUGH MID WEEK. TUESDAY WILL BE THE TRANSITION DAY AS WINDS VEER
BETWEEN E/NE EARLY TO SOUTH LATE...AND THEN EVEN FURTHER TO SW ON
WEDNESDAY THANKS TO RETURN FLOW DEVELOPING AROUND THE SURFACE HIGH.
ALTHOUGH THIS VARIETY OF WIND DIRECTION MAY CAUSE A CONFUSED
SPECTRUM TUESDAY...WIND SPEEDS WILL BE LIGHT AROUND 10 KTS...SO WAVE
AMPLITUDES WILL BE 1-3 FT TUESDAY. AS THE SW WINDS BECOME DOMINANT
WEDNESDAY...SEAS WILL REMAIN 1-3 FT BUT A GROUND SWELL WILL BEGIN TO
INCREASE IN AMPLITUDE WITHIN THE SPECTRUM.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SHK
NEAR TERM...SHK
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...DL
AREA FORECAST DISCUSSION
NWS BISMARCK ND
541 PM CDT SAT SEP 5 2015
.UPDATE...
ISSUED AT 534 PM CDT SAT SEP 5 2015
UPDATE TO CLEAN UP POPS A BIT ACROSS CENTRAL NORTH DAKOTA. SHOWERS
AND SCATTERED THUNDERSTORMS CONTINUE TO LIFT NORTHEAST ACROSS
CENTRAL NORTH DAKOTA. THE WEST AND SOUTH CENTRAL HAVE CLEARED OUT
AND HAVE LOWERED POPS...AT LEAST FOR A WHILE. STILL REMAINS VERY
UNSTABLE OUT WEST AND ANOTHER ROUND OF CONVECTION IS EXPECTED TO
DEVELOP OVER SOUTHEAST MONTANA LATE THIS AFTERNOON OR EARLY
EVENING AND TRACK INTO WESTERN NORTH DAKOTA. WILL CONTINUE TO
MONITOR FOR POSSIBLE SEVERE...BUT FOR THE TIME BEING A LITTLE
BREAK IN THE CONVECTION ACROSS THE WEST.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 230 PM CDT SAT SEP 5 2015
THUNDERSTORM POTENTIAL THIS AFTERNOON THROUGH TONIGHT HIGHLIGHTS
THE SHORT TERM FORECAST.
AS OF 1930 UTC...TWO CONVECTIVE COMPLEXES ACROSS CENTRAL NORTH
DAKOTA IN ASSOCIATION WITH A SHORTWAVE ACROSS NORTH CENTRAL SOUTH
DAKOTA...AND A THIRD COMPLEX ACROSS NORTHWEST NORTH DAKOTA ON THE
APEX OF THE LOW LEVEL JET WHERE WARM AIR ADVECTION IS BEING
MAXIMIZED...WILL CONTINUE TO PROPAGATE NORTHEAST THROUGH THE
AFTERNOON. LOCALLY HEAVY RAINFALL IS THE PRIMARY THREAT WITH THESE
PRECIPITATION AREAS. SPC HAS UPGRADED THE SOUTHWEST TO A SLIGHT
RISK FOR SEVERE STORMS THIS AFTERNOON AND EVENING. WHILE
CONVECTIVE COVERAGE WILL BE MORE SCATTERED...THE AREA IS BEGINNING
TO CLEAR OUT WITH 60S F DEWPOINTS IN PLACE UNDER FAVORABLE
SOUTHWEST FLOW ALOFT.
FOR LATE THIS EVENING AND INTO THE OVERNIGHT...THE 14-18 UTC
OPERATIONAL AND EXPERIMENTAL HRRR ITERATIONS...12 UTC NAM NEST AND
12 UTC WRF-ARW/NMM RUNS ALL SHOW A CONVECTIVE COMPLEX PROPAGATING
OUT OF MONTANA INTO WESTERN NORTH DAKOTA ASSOCIATED WITH STRONG
DIFFLUENCE AHEAD OF THE DEEPENING UPPER LEVEL LOW ACROSS SOUTHEAST
ALBERTA. CERTAINLY COULD NOT RULE OUT A STRONG TO SEVERE STORM
WITH AROUND 1000 J/KG OF ELEVATED CAPE AND AROUND 30-40KTS OF DEEP
LAYER SHEAR. IN REGARDS TO FOG FOR TONIGHT...A SIMILAR SETUP IS
IN PLACE FOR TONIGHT AS IT WAS LAST NIGHT...SO ADDED FOG TO MOST
OF THE AREA. THE DRY SLOT OF THE AFOREMENTIONED LOW WILL OVERTAKE
WESTERN AND CENTRAL NORTH DAKOTA ON SUNDAY...WITH A
COOLER...BREEZY BUT DRIER SUNDAY AHEAD.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 534 PM CDT SAT SEP 5 2015
IFR STRATUS AND PATCHY FOG FROM THIS MORNING HAS IMPROVED THIS
AFTERNOON. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ACROSS
THE NORTH CENTRAL AND EAST WILL CONTINUE...WITH ANOTHER ROUND
ENTERING WESTERN NORTH DAKOTA TONIGHT. FOG AND STRATUS IS EXPECTED
ONCE AGAIN LATE TONIGHT INTO SUNDAY MORNING ACROSS MUCH OF THE
AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 230 PM CDT SAT SEP 5 2015
IFR STRATUS AND PATCHY FOG FROM THIS MORNING WILL SLOWLY IMPROVE
THIS AFTERNOON. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS
ACROSS THE AREA THIS AFTERNOON WILL CONTINUE...WITH ANOTHER ROUND
ENTERING WESTERN NORTH DAKOTA TONIGHT. FOG AND STRATUS IS
EXPECTED ONCE AGAIN LATE TONIGHT INTO SUNDAY MORNING ACROSS MUCH
OF THE AREA.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
244 PM CDT SAT SEP 5 2015
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 230 PM CDT SAT SEP 5 2015
THUNDERSTORM POTENTIAL THIS AFTERNOON THROUGH TONIGHT HIGHLIGHTS
THE SHORT TERM FORECAST.
AS OF 1930 UTC...TWO CONVECTIVE COMPLEXES ACROSS CENTRAL NORTH
DAKOTA IN ASSOCIATION WITH A SHORTWAVE ACROSS NORTH CENTRAL SOUTH
DAKOTA...AND A THIRD COMPLEX ACROSS NORTHWEST NORTH DAKOTA ON THE
APEX OF THE LOW LEVEL JET WHERE WARM AIR ADVECTION IS BEING
MAXIMIZED...WILL CONTINUE TO PROPAGATE NORTHEAST THROUGH THE
AFTERNOON. LOCALLY HEAVY RAINFALL IS THE PRIMARY THREAT WITH THESE
PRECIPITATION AREAS. SPC HAS UPGRADED THE SOUTHWEST TO A SLIGHT
RISK FOR SEVERE STORMS THIS AFTERNOON AND EVENING. WHILE
CONVECTIVE COVERAGE WILL BE MORE SCATTERED...THE AREA IS BEGINNING
TO CLEAR OUT WITH 60S F DEWPOINTS IN PLACE UNDER FAVORABLE
SOUTHWEST FLOW ALOFT.
FOR LATE THIS EVENING AND INTO THE OVERNIGHT...THE 14-18 UTC
OPERATIONAL AND EXPERIMENTAL HRRR ITERATIONS...12 UTC NAM NEST AND
12 UTC WRF-ARW/NMM RUNS ALL SHOW A CONVECTIVE COMPLEX PROPAGATING
OUT OF MONTANA INTO WESTERN NORTH DAKOTA ASSOCIATED WITH STRONG
DIFFLUENCE AHEAD OF THE DEEPENING UPPER LEVEL LOW ACROSS SOUTHEAST
ALBERTA. CERTAINLY COULD NOT RULE OUT A STRONG TO SEVERE STORM
WITH AROUND 1000 J/KG OF ELEVATED CAPE AND AROUND 30-40KTS OF DEEP
LAYER SHEAR. IN REGARDS TO FOG FOR TONIGHT...A SIMILAR SETUP IS
IN PLACE FOR TONIGHT AS IT WAS LAST NIGHT...SO ADDED FOG TO MOST
OF THE AREA. THE DRY SLOT OF THE AFOREMENTIONED LOW WILL OVERTAKE
WESTERN AND CENTRAL NORTH DAKOTA ON SUNDAY...WITH A
COOLER...BREEZY BUT DRIER SUNDAY AHEAD.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 230 PM CDT SAT SEP 5 2015
THE LONG TERM APPEARS QUIET AND COOL.
WESTERLY FLOW ALOFT WILL BRING MILD TEMPERATURES INTO THE REGION
THROUGH NEXT WEEK. TEMPERATURES WILL HOVER NEAR NORMAL WITH
READINGS IN THE UPPER 60S AND 70S DURING THE DAY AND 40S AT NIGHT.
WESTERLY FLOW ALOFT SHOULD LIMIT ANY MAJOR STORM SYSTEMS FROM
IMPACTING THE REGION THROUGH THE NEXT WEEK. HOWEVER...SEVERAL
QUICK MOVING SHORTWAVE TROUGHS MAY MOVE THROUGH AND BRING A SLIGHT
CHANCE FOR SOME SHOWERS AND THUNDERSTORMS MIDWEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 230 PM CDT SAT SEP 5 2015
IFR STRATUS AND PATCHY FOG FROM THIS MORNING WILL SLOWLY IMPROVE
THIS AFTERNOON. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS
ACROSS THE AREA THIS AFTERNOON WILL CONTINUE...WITH ANOTHER ROUND
ENTERING WESTERN NORTH DAKOTA TONIGHT. FOG AND STRATUS IS
EXPECTED ONCE AGAIN LATE TONIGHT INTO SUNDAY MORNING ACROSS MUCH
OF THE AREA.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AYD
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
118 PM CDT SAT SEP 5 2015
.UPDATE...
ISSUED AT 107 PM CDT SAT SEP 5 2015
AS OF 18 UTC...TWO CONVECTIVE COMPLEXES ACROSS THE CENTRAL DAKOTAS
IN ASSOCIATION WITH A SHORTWAVE ACROSS NORTH CENTRAL SOUTH
DAKOTA...AND A THIRD COMPLEX ACROSS NORTHWEST NORTH DAKOTA ON THE
APEX OF THE LOW LEVEL JET WHERE WARM AIR ADVECTION IS BEING
MAXIMIZED...WILL CONTINUE TO PROPAGATE NORTHEAST THROUGH THE
AFTERNOON. LOCALLY HEAVY RAINFALL IS THE PRIMARY THREAT WITH THESE
PRECIPITATION AREAS. SPC HAS UPGRADED THE SOUTHWEST TO A SLIGHT
RISK FOR SEVERE STORMS THIS AFTERNOON AND EVENING. WHILE
CONVECTIVE COVERAGE WILL BE MORE SCATTERED...THE AREA IS
BEGINNING TO CLEAR OUT WITH 60S F DEWPOINTS IN PLACE UNDER
FAVORABLE SOUTHWEST FLOW ALOFT.
UPDATE ISSUED AT 951 AM CDT SAT SEP 5 2015
NO SIGNIFICANT CHANGES WITH THIS FORECAST UPDATE. EXPECT A PEAK IN
PRECIPITATION COVERAGE BETWEEN NOW AND MID DAY...DECREASING
THEREAFTER THROUGH THE LATE AFTERNOON AND EARLY EVENING AS THE
SHORTWAVE ACROSS CENTRAL SOUTH DAKOTA THIS MORNING PROPAGATES INTO
NORTHEAST NORTH DAKOTA. SPC HAS MAINTAINED OUR AREA IN A MARGINAL
RISK FOR SEVERE STORMS. THIS IS PLAUSIBLE...YET DEPENDENT ON
HEATING IN LIGHT OF THE WIDESPREAD CLOUD COVER THIS MORNING.
SHOULD CLOUD COVER THIN A BIT...WHICH IS MOST LIKELY ACROSS THE
SOUTHWEST... 60S F DEWPOINTS IN PLACE UNDER SOUTHWEST FLOW ALOFT
WOULD SUPPORT THE POTENTIAL FOR A SEVERE STORM OR TWO.
FOR LATE THIS EVENING AND INTO THE OVERNIGHT...THE 10-13 UTC
OPERATIONAL AND EXPERIMENTAL HRRR ITERATIONS...12 UTC NAM NEST AND
00 UTC WRF-ARW/NMM RUNS ALL SHOW A CONVECTIVE COMPLEX PROPAGATING
OUT OF MONTANA INTO WESTERN NORTH DAKOTA ASSOCIATED WITH STRONG
DIFFLUENCE AHEAD OF THE DEEPENING UPPER LEVEL LOW ACROSS
SOUTHEAST ALBERTA. CERTAINLY COULD NOT RULE OUT A STRONG TO SEVERE
STORM WITH AROUND 1000 J/KG OF ELEVATED CAPE AND AROUND 30-40KTS
OF DEEP LAYER SHEAR.
UPDATE ISSUED AT 603 AM CDT SAT SEP 5 2015
FOR MORNING UPDATE HAVE ADJUSTED POPS A BIT TOWARDS CURRENT
TRENDS WHICH SEEM TO BE PICKED UP RATHER WELL BY THE HRRR MODEL.
HEAVIER PRECIPITATION WILL CONTINUE TO PUSH NORTH TOWARDS
CANADA...BUT BEHIND IT A LINE OF SHOWERS/THUNDERSTORMS STRETCHING
SOUTHWARD WILL SHIFT EASTWARD AND FILL IN A BIT. HAVE ALSO BUMPED
UP FOG COVERAGE A BIT OVER SOUTH CENTRAL NORTH DAKOTA INTO THE
JAMES RIVER VALLEY WHERE VISIBILITIES HAVE DIPPED DOWN TO AROUND
1/4 MILE AT TIMES. THE COVERAGE OF THIS IS NOT WIDESPREAD SO WILL
REFRAIN FROM ISSUING AN ADVISORY...BUT WILL COVER WITH A SPECIAL
WEATHER STATEMENT FOR EARLY THIS MORNING.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY AFTERNOON)
ISSUED AT 410 AM CDT SAT SEP 5 2015
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD CONTINUES TO BE
SHOWER AND THUNDERSTORM POTENTIAL.
CURRENTLY...STRONG EMBEDDED S/WV LIFTING NORTH-NORTHEAST INTO
WESTERN NORTH DAKOTA RESPONSIBLE FOR ROBUST CONVECTION NOW MOVING
INTO MY NORTHWEST AND NORTH CENTRAL. THIS ACTIVITY WILL QUICKLY
MOVE NORTH OF THE CANADIAN BORDER BY 12Z. CONTINUED CHANCES FOR
SHOWERS AND THUNDERSTORMS THIS MORNING WEST AHEAD OF AN UPPER
LEVEL JET AND NEAR A QUASI-STATIONARY FRONTAL BOUNDARY.
ONCE AGAIN A WIDE VARIETY OF SOLUTIONS WITH FORECAST QPF FOR
TODAY. HOWEVER...THERE APPEARS TO BE A DECENT ENOUGH CONSENSUS TO
KEEP HIGH POPS CENTRAL INTO EAST THIS MORNING INTO THE AFTERNOON
WITH ANOTHER STRONG EMBEDDED WAVE LIFTING NORTH-NORTHEAST ACROSS
CENTRAL SOUTH DAKOTA THIS MORNING AND INTO EASTERN NORTH DAKOTA
THIS AFTERNOON. FORCING WILL BE ENHANCED AS THE NOSE OF A STRONG
UPPER LEVEL JET PUSHES NORTHEAST INTO THE DAKOTAS. FOCUSED HIGHER
POPS ALONG THE AFOREMENTIONED QUASI-STATIONARY BOUNDARY. STRONG
MOISTURE FEED CONTINUES FROM TROPICAL STORM KEVIN...SO HEAVY
RAINERS WILL ONCE AGAIN BE POSSIBLE TODAY. IN ADDITION...A FEW
STRONGER STORMS ONCE AGAIN POSSIBLE 1-1.5K MUCAPE AND AROUND 35KTS
OF WIND SHEAR.
THE UPPER JET WILL FORCE THE STATIONARY SFC LOW FINALLY OFF TO
OUR NORTH AND EAST THIS EVENING INTO THE OVERNIGHT ALLOWING FOR A
DRY WESTERLY FLOW TO DEVELOP INTO THE WESTERN DAKOTAS AFTER 00Z.
LINGERING PRECIPITATION POSSIBLE EAST WITH BETTER CHANCES
NORTHWEST AND NORTH CENTRAL TONIGHT NEAR THE TRACK OF THE BASE OF
THE WEST COAST TROUGH LIFTING NORTHEAST ACROSS MONTANA AND INTO
SASKATCHEWAN. ALL AREAS SHOULD BE DRY BY SUNDAY AFTERNOON AS THE
DRY WESTERLY FLOW CONTINUES TO EXPAND ACROSS THE NORTHERN PLAINS.
BREEZY BUT PLEASANT FOR SUNDAY AS SFC DEWPOINT TEMPERATURES FALL
FROM THE 60S AND LOW 70S WE HAVE SEEN THE PAST COUPLE OF DAYS
DOWN INTO THE 40S AND LOW 50S BY SUNDAY AFTERNOON.
.LONG TERM...(SUNDAY EVENING THROUGH FRIDAY)
ISSUED AT 345 AM CDT SAT SEP 5 2015
QUIET WEATHER IS EXPECTED SUNDAY NIGHT AS BROAD AREA OF
PRECIPITATION CONTINUES TO LIFT TO THE NORTHEAST. ON
MONDAY...AREA WILL BE UNDER COOL BROAD CYCLONIC FLOW. THIS MAY
LEAD TO SOME SHOWERS DEVELOPING...AND POSSIBLY A WEAK THUNDERSTORM
OR TWO...OVER SOUTH CENTRAL NORTH DAKOTA INTO THE JAMES RIVER
VALLEY. QUIET WEATHER RETURNS IN THE EVENING WITH LOSS OF DAYTIME
HEATING. QUIET WEATHER IS EXPECTED ON MONDAY WITH WEAK RIDGE
PASSING OVER...THOUGH TEMPERATURES WILL REMAIN COOL. THROUGH THE
REMAINDER OF THE WEEK WILL HAVE OCCASIONAL LOW CHANCES FOR
PRECIPITATION AS A VARIETY OF WEAK DISTURBANCES PASS THROUGH.
TEMPERATURES WILL GRADUALLY WARM TOWARDS THE END OF THE WEEK WITH
RIDGING OVER THE WESTERN CONUS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 107 PM CDT SAT SEP 5 2015
IFR STRATUS AND PATCHY FOG FROM THIS MORNING WILL SLOWLY IMPROVE
THIS AFTERNOON. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS
ACROSS THE AREA THIS AFTERNOON WILL CONTINUE...WITH ANOTHER ROUND
ENTERING WESTERN NORTH DAKOTA TONIGHT. FOG AND STRATUS IS
EXPECTED ONCE AGAIN LATE TONIGHT INTO SUNDAY MORNING ACROSS MUCH
OF THE AREA.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...NH
LONG TERM...JJS
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1010 AM CDT SAT SEP 5 2015
.UPDATE...
ISSUED AT 1010 AM CDT SAT SEP 5 2015
ADJUSTED POPS A BIT FOR CURRENT RADAR TRENDS. THINK WE SHOULD STAY
DRY UNTIL THIS AFTERNOON WHEN THE PRECIP IN WESTERN AND CENTRAL ND
AND SD BEGINS TO MOVE INTO OUR WESTERN COUNTIES. STILL SOME
UNCERTAINTY ON HOW STRONG THE STORMS WILL BE...AS EVEN OUR EASTERN
COUNTIES WHERE THERE HAS BEEN CLEARING ON THE WARM SIDE OF THE
FRONT ARE SEEING MORE CLOUDS MOVE IN. MARGINAL RISK SEEMS ON TRACK
AT THIS POINT BUT WILL MONITOR. FOG ON THE COOL SIDE OF THE FRONT
HAS ALSO BEEN STICKING AROUND LONGER THAN EXPECTED SO EXTENDED THE
MENTION. LOWERED HIGHS A BIT ACROSS THE CWA FOR INCREASED CLOUD
COVER.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 334 AM CDT SAT SEP 5 2015
CONCERN FOR TODAY WILL AGAIN BE SEVERE THUNDERSTORM AND HEAVY RAIN
POTENTIAL. MUCH LIKE YESTERDAY...STRENGTH OF STORMS WILL DEPEND ON
TIMING OF UPPER WAVE AND CLOUD COVER. THE SHORTWAVE OF THE DAY IS
CURRENTLY (08Z) LOCATED ACROSS WESTERN NEBRASKA AND WILL PROPAGATE
TO THE NE THROUGH THE DAY. EXPECTED TIMING OF THIS FEATURE WILL
BRING FORCING INTO THE SOUTHERN FA AFTER 18Z...AND INTO THE
NORTHERN FA AFTER 21Z. THIS TIMING IS SLIGHTLY SLOWER COMPARED
WITH FRIDAY...WHICH MAY ALLOW MORE TIME FOR HEATING. DEEP LAYER
SHEAR WILL NOT BE MUCH STRONGER TODAY...AND SEVERE POTENTIAL WILL
DEPEND ON ENHANCED INSTABILITY DUE TO HEATING. AS OF 08Z...LOW
CLOUDS ON THE COOL SIDE OF THE SFC BOUNDARY ARE ADVANCING TO THE
SOUTH/SOUTHEAST. ANTICIPATE THIS SOUTH/SOUTHEAST ADVANCEMENT OF
CLOUDS TO STALL AROUND MID-MORNING FROM AROUND BEMIDJI TO WAHPETON
(FOLLOWING THE HRRR). ALTHOUGH CLOUDS WILL LIKELY REMAIN ACROSS
MUCH OF EASTERN NORTH DAKOTA...THERE IS THE POTENTIAL FOR
CLEARING ACROSS THE MINNESOTA COUNTIES. MOST CAMS INDICATE THE
BEST POTENTIAL FOR SEVERE STORMS WILL BE TOWARD LATE AFTERNOON
ACROSS NW MN (WHERE FORCING WILL ARRIVE LAST...PROVIDING MORE TIME
FOR HEATING AND GREATER INSTABILITY). WITH PWATS NEAR 2 INCHES
EXPECTED...LOCALLY HEAVY RAIN WILL ALSO BE A CONCERN...ALTHOUGH
THE ENTIRE SYSTEM SHOULD BE PROGRESSIVE AND LIMIT THE COVERAGE OF
FLASH FLOOD POTENTIAL. WILL MENTION RW+ ACROSS NW MN WHERE STRONGER
STORMS ARE MORE LIKELY. CONSIDERING THE MANY VARIABLES
INVOLVED...WILL NOT YET MENTION T+.
COLD FRONT WILL MOVE THROUGH THE REGION ON SUNDAY...WITH
THUNDERSTORMS AGAIN POSSIBLE. TIMING WILL DETERMINE SEVERE
POTENTIAL...WITH MOST GUIDANCE SUGGESTING BEST CHANCES EAST OF THE
REGION (ALTHOUGH SPC DID PLACE THE FAR EASTERN FA IN A SLIGHT
RISK).
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 320 AM CDT SAT SEP 5 2015
SUNDAY NIGHT-MONDAY NIGHT...COOL AND DRY AIRMASS WILL BE IN PLACE.
CYCLONIC FLOW ALOFT MAY LEAD TO SOME SHOWERS.
TUESDAY-FRIDAY...PERIOD BEGINS WITH ZONAL FLOW ALOFT AND AN UPPER
WAVE MOVING ACROSS THE NORTHERN TIER WITH ASSOCIATED COLD FRONT.
THIS WILL BRING A CHANCE OF CONVECTION TO PORTIONS OF NORTHWEST
AND W CNTRL MN. LWT THEN MOVES ACROSS MN THU NIGHT INTO FRI WITH
NW FLOW PATTERN SETTING UP FOR THE END OF THE WEEK. SFC HIGH
PRESSURE OVER THE DAKOTAS SHOULD KEEP REGION DRY FROM FRIDAY INTO
THE WEEKEND. DAYTIME HIGHS WILL BE SEASONALLY COOL WITH MAX TEMPS
THU AND FRI STRUGGLING TO REACH THE 70S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 631 AM CDT SAT SEP 5 2015
LIFR CIGS AFFECTING MOST AREAS EARLY THIS MORNING (EXCEPT FARGO).
THESE CIGS WILL GRADUALLY RISE THROUGH THE DAY...OR MOVE NORTH AS
THE NEXT SYSTEM MOVES TOWARD THE REGION. USED HRRR GUIDANCE FOR
TIMING OF CIGS. THUNDERSTORMS EXPECTED THIS AFTERNOON AND EVENING
ACROSS MUCH OF THE REGION.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...TG
LONG TERM...TG/SPEICHER
AVIATION...TG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1002 AM CDT SAT SEP 5 2015
.UPDATE...
ISSUED AT 951 AM CDT SAT SEP 5 2015
NO SIGNIFICANT CHANGES WITH THIS FORECAST UPDATE. EXPECT A PEAK IN
PRECIPITATION COVERAGE BETWEEN NOW AND MID DAY...DECREASING
THEREAFTER THROUGH THE LATE AFTERNOON AND EARLY EVENING AS THE
SHORTWAVE ACROSS CENTRAL SOUTH DAKOTA THIS MORNING PROPAGATES INTO
NORTHEAST NORTH DAKOTA. SPC HAS MAINTAINED OUR AREA IN A MARGINAL
RISK FOR SEVERE STORMS. THIS IS PLAUSIBLE...YET DEPENDENT ON
HEATING IN LIGHT OF THE WIDESPREAD CLOUD COVER THIS MORNING.
SHOULD CLOUD COVER THIN A BIT...WHICH IS MOST LIKELY ACROSS THE
SOUTHWEST... 60S F DEWPOINTS IN PLACE UNDER SOUTHWEST FLOW ALOFT
WOULD SUPPORT THE POTENTIAL FOR A SEVERE STORM OR TWO.
FOR LATE THIS EVENING AND INTO THE OVERNIGHT...THE 10-13 UTC
OPERATIONAL AND EXPERIMENTAL HRRR ITERATIONS...12 UTC NAM NEST AND
00 UTC WRF-ARW/NMM RUNS ALL SHOW A CONVECTIVE COMPLEX PROPAGATING
OUT OF MONTANA INTO WESTERN NORTH DAKOTA ASSOCIATED WITH STRONG
DIFFLUENCE AHEAD OF THE DEEPENING UPPER LEVEL LOW ACROSS
SOUTHEAST ALBERTA. CERTAINLY COULD NOT RULE OUT A STRONG TO SEVERE
STORM WITH AROUND 1000 J/KG OF ELEVATED CAPE AND AROUND 30-40KTS
OF DEEP LAYER SHEAR.
UPDATE ISSUED AT 603 AM CDT SAT SEP 5 2015
FOR MORNING UPDATE HAVE ADJUSTED POPS A BIT TOWARDS CURRENT
TRENDS WHICH SEEM TO BE PICKED UP RATHER WELL BY THE HRRR MODEL.
HEAVIER PRECIPITATION WILL CONTINUE TO PUSH NORTH TOWARDS
CANADA...BUT BEHIND IT A LINE OF SHOWERS/THUNDERSTORMS STRETCHING
SOUTHWARD WILL SHIFT EASTWARD AND FILL IN A BIT. HAVE ALSO BUMPED
UP FOG COVERAGE A BIT OVER SOUTH CENTRAL NORTH DAKOTA INTO THE
JAMES RIVER VALLEY WHERE VISIBILITIES HAVE DIPPED DOWN TO AROUND
1/4 MILE AT TIMES. THE COVERAGE OF THIS IS NOT WIDESPREAD SO WILL
REFRAIN FROM ISSUING AN ADVISORY...BUT WILL COVER WITH A SPECIAL
WEATHER STATEMENT FOR EARLY THIS MORNING.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY AFTERNOON)
ISSUED AT 410 AM CDT SAT SEP 5 2015
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD CONTINUES TO BE
SHOWER AND THUNDERSTORM POTENTIAL.
CURRENTLY...STRONG EMBEDDED S/WV LIFTING NORTH-NORTHEAST INTO
WESTERN NORTH DAKOTA RESPONSIBLE FOR ROBUST CONVECTION NOW MOVING
INTO MY NORTHWEST AND NORTH CENTRAL. THIS ACTIVITY WILL QUICKLY
MOVE NORTH OF THE CANADIAN BORDER BY 12Z. CONTINUED CHANCES FOR
SHOWERS AND THUNDERSTORMS THIS MORNING WEST AHEAD OF AN UPPER
LEVEL JET AND NEAR A QUASI-STATIONARY FRONTAL BOUNDARY.
ONCE AGAIN A WIDE VARIETY OF SOLUTIONS WITH FORECAST QPF FOR
TODAY. HOWEVER...THERE APPEARS TO BE A DECENT ENOUGH CONSENSUS TO
KEEP HIGH POPS CENTRAL INTO EAST THIS MORNING INTO THE AFTERNOON
WITH ANOTHER STRONG EMBEDDED WAVE LIFTING NORTH-NORTHEAST ACROSS
CENTRAL SOUTH DAKOTA THIS MORNING AND INTO EASTERN NORTH DAKOTA
THIS AFTERNOON. FORCING WILL BE ENHANCED AS THE NOSE OF A STRONG
UPPER LEVEL JET PUSHES NORTHEAST INTO THE DAKOTAS. FOCUSED HIGHER
POPS ALONG THE AFOREMENTIONED QUASI-STATIONARY BOUNDARY. STRONG
MOISTURE FEED CONTINUES FROM TROPICAL STORM KEVIN...SO HEAVY
RAINERS WILL ONCE AGAIN BE POSSIBLE TODAY. IN ADDITION...A FEW
STRONGER STORMS ONCE AGAIN POSSIBLE 1-1.5K MUCAPE AND AROUND 35KTS
OF WIND SHEAR.
THE UPPER JET WILL FORCE THE STATIONARY SFC LOW FINALLY OFF TO
OUR NORTH AND EAST THIS EVENING INTO THE OVERNIGHT ALLOWING FOR A
DRY WESTERLY FLOW TO DEVELOP INTO THE WESTERN DAKOTAS AFTER 00Z.
LINGERING PRECIPITATION POSSIBLE EAST WITH BETTER CHANCES
NORTHWEST AND NORTH CENTRAL TONIGHT NEAR THE TRACK OF THE BASE OF
THE WEST COAST TROUGH LIFTING NORTHEAST ACROSS MONTANA AND INTO
SASKATCHEWAN. ALL AREAS SHOULD BE DRY BY SUNDAY AFTERNOON AS THE
DRY WESTERLY FLOW CONTINUES TO EXPAND ACROSS THE NORTHERN PLAINS.
BREEZY BUT PLEASANT FOR SUNDAY AS SFC DEWPOINT TEMPERATURES FALL
FROM THE 60S AND LOW 70S WE HAVE SEEN THE PAST COUPLE OF DAYS
DOWN INTO THE 40S AND LOW 50S BY SUNDAY AFTERNOON.
.LONG TERM...(SUNDAY EVENING THROUGH FRIDAY)
ISSUED AT 345 AM CDT SAT SEP 5 2015
QUIET WEATHER IS EXPECTED SUNDAY NIGHT AS BROAD AREA OF
PRECIPITATION CONTINUES TO LIFT TO THE NORTHEAST. ON
MONDAY...AREA WILL BE UNDER COOL BROAD CYCLONIC FLOW. THIS MAY
LEAD TO SOME SHOWERS DEVELOPING...AND POSSIBLY A WEAK THUNDERSTORM
OR TWO...OVER SOUTH CENTRAL NORTH DAKOTA INTO THE JAMES RIVER
VALLEY. QUIET WEATHER RETURNS IN THE EVENING WITH LOSS OF DAYTIME
HEATING. QUIET WEATHER IS EXPECTED ON MONDAY WITH WEAK RIDGE
PASSING OVER...THOUGH TEMPERATURES WILL REMAIN COOL. THROUGH THE
REMAINDER OF THE WEEK WILL HAVE OCCASIONAL LOW CHANCES FOR
PRECIPITATION AS A VARIETY OF WEAK DISTURBANCES PASS THROUGH.
TEMPERATURES WILL GRADUALLY WARM TOWARDS THE END OF THE WEEK WITH
RIDGING OVER THE WESTERN CONUS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 951 AM CDT SAT SEP 5 2015
IFR-VLIFR STRATUS AND PATCHY FOG DEVELOPING ACROSS ALL TERMINALS
EARLY THIS SATURDAY MORNING AND SHOULD PERSIST THROUGH THE AM
HOURS. SCATTERED SHOWERS AND THUNDERSTORMS ACROSS WESTERN INTO
NORTH CENTRAL NORTH DAKOTA EARLY THIS SATURDAY MORNING...WITH
THIS ACTIVITY CONTINUING/REDEVELOPING CENTRAL INTO EAST LATER
THIS MORNING AND INTO THE AFTERNOON. FOG AND STRATUS IS EXPECTED
ONCE AGAIN LATE TONIGHT INTO SUNDAY MORNING ACROSS MUCH OF THE
AREA.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...NH
LONG TERM...JJS
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
631 AM CDT SAT SEP 5 2015
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 334 AM CDT SAT SEP 5 2015
CONCERN FOR TODAY WILL AGAIN BE SEVERE THUNDERSTORM AND HEAVY RAIN
POTENTIAL. MUCH LIKE YESTERDAY...STRENGTH OF STORMS WILL DEPEND ON
TIMING OF UPPER WAVE AND CLOUD COVER. THE SHORTWAVE OF THE DAY IS
CURRENTLY (08Z) LOCATED ACROSS WESTERN NEBRASKA AND WILL PROPAGATE
TO THE NE THROUGH THE DAY. EXPECTED TIMING OF THIS FEATURE WILL
BRING FORCING INTO THE SOUTHERN FA AFTER 18Z...AND INTO THE
NORTHERN FA AFTER 21Z. THIS TIMING IS SLIGHTLY SLOWER COMPARED
WITH FRIDAY...WHICH MAY ALLOW MORE TIME FOR HEATING. DEEP LAYER
SHEAR WILL NOT BE MUCH STRONGER TODAY...AND SEVERE POTENTIAL WILL
DEPEND ON ENHANCED INSTABILITY DUE TO HEATING. AS OF 08Z...LOW
CLOUDS ON THE COOL SIDE OF THE SFC BOUNDARY ARE ADVANCING TO THE
SOUTH/SOUTHEAST. ANTICIPATE THIS SOUTH/SOUTHEAST ADVANCEMENT OF
CLOUDS TO STALL AROUND MID-MORNING FROM AROUND BEMIDJI TO WAHPETON
(FOLLOWING THE HRRR). ALTHOUGH CLOUDS WILL LIKELY REMAIN ACROSS
MUCH OF EASTERN NORTH DAKOTA...THERE IS THE POTENTIAL FOR
CLEARING ACROSS THE MINNESOTA COUNTIES. MOST CAMS INDICATE THE
BEST POTENTIAL FOR SEVERE STORMS WILL BE TOWARD LATE AFTERNOON
ACROSS NW MN (WHERE FORCING WILL ARRIVE LAST...PROVIDING MORE TIME
FOR HEATING AND GREATER INSTABILITY). WITH PWATS NEAR 2 INCHES
EXPECTED...LOCALLY HEAVY RAIN WILL ALSO BE A CONCERN...ALTHOUGH
THE ENTIRE SYSTEM SHOULD BE PROGRESSIVE AND LIMIT THE COVERAGE OF
FLASH FLOOD POTENTIAL. WILL MENTION RW+ ACROSS NW MN WHERE STRONGER
STORMS ARE MORE LIKELY. CONSIDERING THE MANY VARIABLES
INVOLVED...WILL NOT YET MENTION T+.
COLD FRONT WILL MOVE THROUGH THE REGION ON SUNDAY...WITH
THUNDERSTORMS AGAIN POSSIBLE. TIMING WILL DETERMINE SEVERE
POTENTIAL...WITH MOST GUIDANCE SUGGESTING BEST CHANCES EAST OF THE
REGION (ALTHOUGH SPC DID PLACE THE FAR EASTERN FA IN A SLIGHT
RISK).
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 320 AM CDT SAT SEP 5 2015
SUNDAY NIGHT-MONDAY NIGHT...COOL AND DRY AIRMASS WILL BE IN PLACE.
CYCLONIC FLOW ALOFT MAY LEAD TO SOME SHOWERS.
TUESDAY-FRIDAY...PERIOD BEGINS WITH ZONAL FLOW ALOFT AND AN UPPER
WAVE MOVING ACROSS THE NORTHERN TIER WITH ASSOCIATED COLD FRONT.
THIS WILL BRING A CHANCE OF CONVECTION TO PORTIONS OF NORTHWEST
AND W CNTRL MN. LWT THEN MOVES ACROSS MN THU NIGHT INTO FRI WITH
NW FLOW PATTERN SETTING UP FOR THE END OF THE WEEK. SFC HIGH
PRESSURE OVER THE DAKOTAS SHOULD KEEP REGION DRY FROM FRIDAY INTO
THE WEEKEND. DAYTIME HIGHS WILL BE SEASONALLY COOL WITH MAX TEMPS
THU AND FRI STRUGGLING TO REACH THE 70S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 631 AM CDT SAT SEP 5 2015
LIFR CIGS AFFECTING MOST AREAS EARLY THIS MORNING (EXCEPT FARGO).
THESE CIGS WILL GRADUALLY RISE THROUGH THE DAY...OR MOVE NORTH AS
THE NEXT SYSTEM MOVES TOWARD THE REGION. USED HRRR GUIDANCE FOR
TIMING OF CIGS. THUNDERSTORMS EXPECTED THIS AFTERNOON AND EVENING
ACROSS MUCH OF THE REGION.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...TG
LONG TERM...TG/SPEICHER
AVIATION...TG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
611 AM CDT SAT SEP 5 2015
.UPDATE...
ISSUED AT 603 AM CDT SAT SEP 5 2015
FOR MORNING UPDATE HAVE ADJUSTED POPS A BIT TOWARDS CURRENT
TRENDS WHICH SEEM TO BE PICKED UP RATHER WELL BY THE HRRR MODEL.
HEAVIER PRECIPITATION WILL CONTINUE TO PUSH NORTH TOWARDS
CANADA...BUT BEHIND IT A LINE OF SHOWERS/THUNDERSTORMS STRETCHING
SOUTHWARD WILL SHIFT EASTWARD AND FILL IN A BIT. HAVE ALSO BUMPED
UP FOG COVERAGE A BIT OVER SOUTH CENTRAL NORTH DAKOTA INTO THE
JAMES RIVER VALLEY WHERE VISIBILITIES HAVE DIPPED DOWN TO AROUND
1/4 MILE AT TIMES. THE COVERAGE OF THIS IS NOT WIDESPREAD SO WILL
REFRAIN FROM ISSUING AN ADVISORY...BUT WILL COVER WITH A SPECIAL
WEATHER STATEMENT FOR EARLY THIS MORNING.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY AFTERNOON)
ISSUED AT 410 AM CDT SAT SEP 5 2015
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD CONTINUES TO BE
SHOWER AND THUNDERSTORM POTENTIAL.
CURRENTLY...STRONG EMBEDDED S/WV LIFTING NORTH-NORTHEAST INTO
WESTERN NORTH DAKOTA RESPONSIBLE FOR ROBUST CONVECTION NOW MOVING
INTO MY NORTHWEST AND NORTH CENTRAL. THIS ACTIVITY WILL QUICKLY
MOVE NORTH OF THE CANADIAN BORDER BY 12Z. CONTINUED CHANCES FOR
SHOWERS AND THUNDERSTORMS THIS MORNING WEST AHEAD OF AN UPPER
LEVEL JET AND NEAR A QUASI-STATIONARY FRONTAL BOUNDARY.
ONCE AGAIN A WIDE VARIETY OF SOLUTIONS WITH FORECAST QPF FOR
TODAY. HOWEVER...THERE APPEARS TO BE A DECENT ENOUGH CONSENSUS TO
KEEP HIGH POPS CENTRAL INTO EAST THIS MORNING INTO THE AFTERNOON
WITH ANOTHER STRONG EMBEDDED WAVE LIFTING NORTH-NORTHEAST ACROSS
CENTRAL SOUTH DAKOTA THIS MORNING AND INTO EASTERN NORTH DAKOTA
THIS AFTERNOON. FORCING WILL BE ENHANCED AS THE NOSE OF A STRONG
UPPER LEVEL JET PUSHES NORTHEAST INTO THE DAKOTAS. FOCUSED HIGHER
POPS ALONG THE AFOREMENTIONED QUASI-STATIONARY BOUNDARY. STRONG
MOISTURE FEED CONTINUES FROM TROPICAL STORM KEVIN...SO HEAVY
RAINERS WILL ONCE AGAIN BE POSSIBLE TODAY. IN ADDITION...A FEW
STRONGER STORMS ONCE AGAIN POSSIBLE 1-1.5K MUCAPE AND AROUND 35KTS
OF WIND SHEAR.
THE UPPER JET WILL FORCE THE STATIONARY SFC LOW FINALLY OFF TO
OUR NORTH AND EAST THIS EVENING INTO THE OVERNIGHT ALLOWING FOR A
DRY WESTERLY FLOW TO DEVELOP INTO THE WESTERN DAKOTAS AFTER 00Z.
LINGERING PRECIPITATION POSSIBLE EAST WITH BETTER CHANCES
NORTHWEST AND NORTH CENTRAL TONIGHT NEAR THE TRACK OF THE BASE OF
THE WEST COAST TROUGH LIFTING NORTHEAST ACROSS MONTANA AND INTO
SASKATCHEWAN. ALL AREAS SHOULD BE DRY BY SUNDAY AFTERNOON AS THE
DRY WESTERLY FLOW CONTINUES TO EXPAND ACROSS THE NORTHERN PLAINS.
BREEZY BUT PLEASANT FOR SUNDAY AS SFC DEWPOINT TEMPERATURES FALL
FROM THE 60S AND LOW 70S WE HAVE SEEN THE PAST COUPLE OF DAYS
DOWN INTO THE 40S AND LOW 50S BY SUNDAY AFTERNOON.
.LONG TERM...(SUNDAY EVENING THROUGH FRIDAY)
ISSUED AT 345 AM CDT SAT SEP 5 2015
QUIET WEATHER IS EXPECTED SUNDAY NIGHT AS BROAD AREA OF
PRECIPITATION CONTINUES TO LIFT TO THE NORTHEAST. ON
MONDAY...AREA WILL BE UNDER COOL BROAD CYCLONIC FLOW. THIS MAY
LEAD TO SOME SHOWERS DEVELOPING...AND POSSIBLY A WEAK THUNDERSTORM
OR TWO...OVER SOUTH CENTRAL NORTH DAKOTA INTO THE JAMES RIVER
VALLEY. QUIET WEATHER RETURNS IN THE EVENING WITH LOSS OF DAYTIME
HEATING. QUIET WEATHER IS EXPECTED ON MONDAY WITH WEAK RIDGE
PASSING OVER...THOUGH TEMPERATURES WILL REMAIN COOL. THROUGH THE
REMAINDER OF THE WEEK WILL HAVE OCCASIONAL LOW CHANCES FOR
PRECIPITATION AS A VARIETY OF WEAK DISTURBANCES PASS THROUGH.
TEMPERATURES WILL GRADUALLY WARM TOWARDS THE END OF THE WEEK WITH
RIDGING OVER THE WESTERN CONUS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 400 AM CDT SAT SEP 5 2015
IFR-VLIFR STRATUS AND PATCHY FOG DEVELOPING ACROSS ALL TERMINALS
EARLY THIS SATURDAY MORNING AND SHOULD PERSIST THROUGH THE AM
HOURS. SCATTERED SHOWERS AND THUNDERSTORMS ACROSS WESTERN INTO
NORTH CENTRAL NORTH DAKOTA EARLY THIS SATURDAY MORNING...WITH
THIS ACTIVITY CONTINUING/REDEVELOPING CENTRAL INTO EAST LATER
THIS MORNING AND INTO THE AFTERNOON.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JJS
SHORT TERM...NH
LONG TERM...JJS
AVIATION...NH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
131 AM CDT SAT SEP 5 2015
.UPDATE...
ISSUED AT 130 AM CDT SAT SEP 5 2015
STRONG S/WV IMPULSE LIFTING NORTH ACROSS THE WESTERN DAKOTAS.
LARGE AREA OF SHOWERS AND THUNDERSTORMS MOVING NORTH WITH THE WAVE
ACROSS EASTERN MT AND SOUTHWESTERN ND WILL CONTINUE TO DEVELOP
NORTH. HIGH RES MODELS THEN BRING ANOTHER WAVE NORTH LATER THIS
MORNING AND AFTERNOON. INCREASED POPS AND ALSO CLOUDY COVER WITH
LARGE AREA OF LOW STRATUS BUILDING SOUTHWARD AS WINDS BECOME MORE
NORTHEAST.
UPDATE ISSUED AT 941 PM CDT FRI SEP 4 2015
NEXT IMPULSE IN SOUTHWEST FLOW IS PRODUCING SHOWERS AND
THUNDERSTORMS FROM FAR SOUTHEAST MONTANA INTO NORTHEAST WYOMING.
THIS ACTIVITY IS TRACKING NORTHEAST AROUND 30-35 MPH AND SHOULD
BEGIN TO MOVE INTO SOUTHWEST NORTH DAKOTA IN THE NEXT FEW HOURS.
LATEST MESOSCALE MODELS SHOW THIS AREA LIFTING THROUGH WESTERN AND
INTO NORTH CENTRAL NORTH DAKOTA THROUGH THE OVERNIGHT HOURS.
UPDATED POP/WX GRIDS BASED ON A BLEND OF THE TIME-LAGGED HRRR AND
PERSISTENCE THROUGH 14 UTC. ALSO EXPANDED OVERCAST CLOUD COVER
ACROSS MAINLY THE NORTH HALF OF THE FORECAST AREA THIS EVENING AND
EXPANDED IT FARTHER SOUTH THROUGH THE OVERNIGHT HOURS.
UPDATE ISSUED AT 637 PM CDT FRI SEP 4 2015
EVEN IN THE SUBSIDENCE BEHIND THE EXITING SHORTWAVE THERE IS STILL
ENOUGH LOW LEVEL INSTABILITY FOR A FEW SHOWERS OR THUNDERSTORMS
OVER CENTRAL NORTH DAKOTA EARLY THIS EVENING. AN ISOLATED
THUNDERSTORM DEVELOPED OVER SHERIDAN COUNTY RECENTLY AS TWO
OUTFLOW BOUNDARIES COLLIDED. WILL KEEP A SLIGHT CHANCE FOR ANOTHER
COUPLE HOURS FROM JUST NORTHEAST OF BISMARCK UP INTO THE TURTLE
MOUNTAINS. LATEST MESOSCALE MODELS ARE SHOWING SHOWERS MOVING INTO
WESTERN NORTH DAKOTA LATER THAN PREVIOUSLY FORECAST. CURRENT
INDICATIONS SUGGEST MORE LIKE AROUND MIDNIGHT OR THEREAFTER. THUS
CUT BACK ON POPS IN THE FAR WEST THIS EVENING. CURRENT RADAR
ANALYSIS INDICATES SHOWER ACTIVITY IS CURRENTLY AROUND GLASGOW AND
FARTHER WEST.
UPDATE ISSUED AT 520 PM CDT FRI SEP 4 2015
QUICK UPDATE FOR POPS/SKY COVER AND TO FRESHEN LATEST SENSIBLE
WEATHER ELEMENTS. SHOWERS HAVE ALL BUT EXITED THE FAR EASTERN
CWA. WILL KEEP A SLIGHT CHANCE OVER FAR EASTERN STUTSMAN INTO
LAMOURE/DICKEY COUNTIES. OTHERWISE EXPECT DRY CONDITIONS INTO THIS
EVENING. CHANCES RETURN OUT WEST AGAIN LATE THIS EVENING.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 225 PM CDT FRI SEP 4 2015
SHOWER AND THUNDERSTORM POTENTIAL TONIGHT THROUGH SATURDAY
HIGHLIGHTS THE SHORT TERM FORECAST.
A BREAK IN PRECIPITATION IS EXPECTED ACROSS NEARLY ALL OF WESTERN
AND CENTRAL NORTH DAKOTA THIS AFTERNOON INTO THE EARLY EVENING
WITH SUBSIDENCE IN THE WAKE OF THE SHORTWAVE PROPAGATING INTO THE
NORTHEASTERN PORTIONS OF THE STATE. THE NEXT WAVE EVIDENT ON WATER
VAPOR IMAGERY ACROSS CENTRAL WYOMING THIS AFTERNOON WILL CONTINUE
TO PROPAGATE NORTHEAST THROUGH THE EVENING AND IMPACT WESTERN
NORTH DAKOTA LATE THIS EVENING AND THROUGH THE OVERNIGHT. AS A
RESULT... SCATTERED SHOWERS AND THUNDERSTORMS RETURN TO THE
FORECAST GENERALLY WEST OF HIGHWAY 83 WITH THIS FEATURE. SEVERE
WEATHER IS NOT EXPECTED. DURING THE DAY ON SATURDAY...RAINFALL IS
EXPECTED TO CONTINUE ACROSS THE NORTHWEST THROUGHOUT THE DAY WITH
MULTIPLE IMPULSES EMBEDDED IN SOUTHWEST FLOW ALOFT. WHILE
NORTHWEST NORTH DAKOTA IS IN THE DAY TWO EXCESSIVE RAINFALL
OUTLOOK...THIS HAS BEEN THE DRIEST PORTION OF THE STATE THIS
SUMMER AND DO NOT ANTICIPATE ANY FLOOD CONCERNS.
ELSEWHERE...EXPECT MORE SCATTERED...DIURNALLY DRIVEN CONVECTIVE
ACTIVITY THROUGH THE AFTERNOON AND EVENING. GIVEN GOOD
AGREEMENT...UTILIZED A BLEND OF THE 12 UTC DETERMINISTIC AND
ENSEMBLE SUITES.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 225 PM CDT FRI SEP 4 2015
COOLER TEMPERATURES HIGHLIGHT THE EXTENDED FORECAST.
THE 12 UTC DETERMINISTIC AND ENSEMBLE SUITES ARE IN GOOD AGREEMENT
ON THE LOW OVER NORTH CENTRAL MONTANA SATURDAY NIGHT PROPAGATING
INTO SASKATCHEWAN THROUGH THE DAY ON SUNDAY. THIS WOULD MARK THE
END OF PRECIPITATION FROM THE SHORT TERM BY SUNDAY MORNING AS
DRIER AIR OVERTAKES THE AREA. THEREAFTER...A MEAN...LOW AMPLITUDE
UPPER LEVEL TROUGH ACROSS THE CENTRAL CONUS FAVORS BELOW NORMAL
TEMPERATURES IN THE 60S AND 70S NEXT WEEK. GIVEN THESE COOLER
TEMPERATES...WILL HAVE TO MONITOR FROST POTENTIAL FOR NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 130 AM CDT SAT SEP 5 2015
IFR-VLIFR STRATUS AND PATCHY FOG DEVELOPING ACROSS ALL TERMINALS
EARLY THIS SATURDAY MORNING AND SHOULD PERSIST THROUGH THE AM
HOURS. SCATTERED SHOWERS AND THUNDERSTORMS ACROSS WESTERN NORTH
DAKOTA LATE TONIGHT INTO SATURDAY MORNING...WITH THIS ACTIVITY
THEN POSSIBLE CENTRAL INTO EAST LATER THIS MORNING AND INTO
SATURDAY AFTERNOON.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...AYD
LONG TERM...AYD
AVIATION...NH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1148 PM CDT FRI SEP 4 2015
.UPDATE...
ISSUED AT 1143 PM CDT FRI SEP 4 2015
MAINTAINED SOME LOW POPS ACROSS THE FAR EAST AS HRRR INDICATING
POSSIBLE REDEVELOPMENT OF SCT TSRA AS CURRENT RADAR INDICATING
SOME WEAK ECHOES DEVELOPING OVER WEST CENTRAL MN. ALSO EXPANDED
FOG MENTION ACROSS NORTHERN MN WHERE HEAVIER RAIN FELL.
UPDATE ISSUED AT 641 PM CDT FRI SEP 4 2015
MOST OF THE SCT SHRA/TSRA HAVE SHIFTED E INTO NW MN AS SHORT WAVE
CONTINUES TO LIFT NE. WILL TREND ENDING OF PCPN FROM SW-NE
GRADUALLY THROUGH THE EVENING WITH ANY LINGERING PCPN OVER THE NE
THIRD OF THE FA BY LATE EVENING. BASED ON CURRENT RADAR TRENDS
LIFTED SEVERE MENTION ACROSS FAR NW MN AS CURRENT CONVECTION HAS
SHOWN NO SIGNS OF INCREASING INTENSITY. NO OTHER SIGNIFICANT
CHANGES TO FORECAST.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 256 PM CDT FRI SEP 4 2015
WHAT HAPPENS WITH THE CONVECTION THIS EVENING AND ROUND TWO
TOMORROW WILL BE THE MAIN HEADACHE FOR THE PERIOD.
WV LOOP SHOWS A STRONG LEAD SHORTWAVE TROUGH CURRENTLY LIFTING
THROUGH EASTERN ND. CONVECTION FIRING ACROSS NORTHEASTERN NORTH
DAKOTA AHEAD OF THE SHORTWAVE HAS WEAKENED AFTER SOME CELLS PULSED
UP TO SEVERE. STILL PLENTY OF MOISTURE WITH DEWPOINTS IN THE UPPER
60S AND 70S...BUT CLOUDS HAVE LINGERED OVER THE AREA MUCH OF THE
DAY AND THE ATMOSPHERE IS WORKED OVER FROM PREVIOUS CONVECTION.
VIS SATELLITE SHOWS A BIT OF THINNING CLOUDS OVER THE CENTRAL
CWA...AND THE SPC MESOANALYSIS FINALLY HAS A BIT OF SFC BASED CAPE
AFTER THE EARLIER ELEVATED CONVECTION. THINK THERE WILL BE A
NARROW WINDOW OF OPPORTUNITY FOR REDEVELOPMENT IF THE NORTHERN CWA
CAN DESTABILIZE AS THE UPPER LOW LIFTS TO THE NORTH. EVEN
THEN...THE DEEP LAYER BULK SHEAR IS NOT VERY IMPRESSIVE...AROUND
30 KTS. SOME MARGINALLY SEVERE REDEVELOPMENT IS POSSIBLE INTO THE
EVENING...BUT THINK THAT MOST AREAS WILL JUST SEE HEAVY RAIN WITH
PWATS NEARING 2 INCHES.
TOMORROW...THE MAIN UPPER TROUGH WILL STILL BE OUT OF THE NORTHERN
ROCKIES...BUT MODELS BRING THROUGH ANOTHER LEAD SHORTWAVE AND THIS
SEEMS REASONABLE GIVEN A WEAK DISTURBANCE CURRENTLY SEEN OVER THE
DESERT SOUTHWEST. MODELS SEEM TO BE IN FAIRLY GOOD AGREEMENT ON A
BREAK IN PRECIP FOR SATURDAY MORNING...AND SOME LOW CLOUDS AND FOG
ARE NOT OUT OF THE QUESTION WITH RECENT RAINFALL. THE SHORTWAVE
TROUGH SHOULD BE COMING IN DURING THE AFTERNOON. SOME QUESTION AS
TO HOW MUCH WE WILL DESTABILIZE...BUT THE NAM AT LEAST HAS SOME
CAPE VALUES NEAR 2000 J/KG...ALTHOUGH THE 40 KTS BULK SHEAR ARE
WEST OF WHERE THE BEST CAPE IS EXPECTED. A STALLED FRONTAL
BOUNDARY OVER THE AREA COULD PROVIDE THE FOCUS FOR SOME
DEVELOPMENT. SOME MARGINALLY SEVERE STORMS WILL BE POSSIBLE BUT
IF THE SHORTWAVE COMES IN EARLIER THAN EXPECTED IT COULD
COMPLICATE THINGS. SOME FAIRLY GOOD QPF IS EXPECTED MAINLY OVER
OUR NORTHEASTERN COUNTIES LATER SATURDAY NIGHT AS THE SHORTWAVE
LIFTS THROUGH. TEMPS WILL BE HIGHLY DEPENDENT ON CLOUDS BUT FOR
NOW HAVE SOME 80S IN THE SOUTH AND 70S IN THE NORTHWEST BEHIND A
STALLED FRONT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 256 PM CDT FRI SEP 4 2015
SUNDAY AND MONDAY...THE UPPER TROUGH WILL LIFT FROM THE NORTHERN
ROCKIES AND INTO SOUTHERN CANADA...WITH ANOTHER LOBE OF THE TROUGH
DIGGING INTO MONTANA AND KEEPING THE NORTHERN PLAINS IN
SOUTHWESTERLY FLOW ALOFT. THE MAIN WAVE MOVING NORTHEAST SHOULD
HELP PUSH A FAIRLY STRONG COLD FRONT THROUGH THE CWA. MODELS VARY
ON HOW MUCH PRECIP OCCURS WITH THE FRONTAL PASSAGE...FOR NOW KEPT
BEST CHANCES IN THE NORTH AND EAST SUNDAY INTO SUNDAY NIGHT. TEMPS
SHOULD STILL BE IN THE 70S AND LOW 80S ON SUNDAY BUT GOOD COOL AIR
ADVECTION WILL HELP KEEP READINGS IN THE 70S FOR MONDAY.
FOR MONDAY NIGHT THROUGH FRIDAY...WILL BE STARTING OFF THE PERIOD
WITH A CLOSED LOW MOVING ACROSS CENTRAL CANADA. WILL SEE WEST-NW
WINDS AND COOL AFTERNOON HIGHS FOR TUE. FLOW BECOMES MORE ZONAL FOR
WED/WED NIGHT WHICH WILL PUSH ANOTHER FRONT THROUGH THE AREA. WILL
KEEP SOME LOW CHANCES FOR PCPN TO ACCOUNT FOR THIS. ONCE THIS FRONT
MOVES THRU THE FLOW TURNS BACK TO THE NORTHWEST FOR THU/FRI.
THEREFORE LOOKING FOR MAINLY DRY BUT COOL CONDITIONS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1143 PM CDT FRI SEP 4 2015
BY MORNING WILL LIKELY SEE BAND OF IFR STRATUS FROM BDE-TVF AND
GFK SOUTHEASTWARD WHICH SHOULD GRADUALLY BURN OFF IN THE AM. COULD
STILL SEE SOME OVERNIGHT TSRA OVER THE FAR EASTERN FA. NEXT T
POTENTIAL LOOKS LIKE LATER SATURDAY AFTERNOON.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...JR
LONG TERM...JR/GODON
AVIATION...VOELKER
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
710 AM EDT SAT SEP 5 2015
.SYNOPSIS...
THE UPPER LEVEL DISTURBANCE OVER MICHIGAN WILL WEAKEN AND LIFT
NORTHEAST TODAY. A BROAD AREA OF HIGH PRESSURE OVER NEW ENGLAND WILL
MOVE SOUTH ALONG THE EAST COAST THROUGH THE HOLIDAY WEEKEND. A
WEAKENING FRONT WILL STALL JUST NORTH OF THE AREA ON TUESDAY...THEN
PUSH SOUTH ON WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CLUSTER OF THUNDERSTORMS WITH EFFICIENT RAINFALL RATES DEVELOPED
OVER THE LAST 2 HOURS PRODUCING HEAVY RAINFALL FROM VANLUE TO
FOSTORIA TO NEAR WOODVILLE. STORM MOTION IS VERY SLOW WITH STORMS
BUILDING TO NORTH AT 5-10 MPH. RADAR ESTIMATES THAT SOME AREAS
HAVE ALREADY HAD OVER 2 INCHES OF RAIN AND ARE MONITORING FOR ANY
FLOODING ISSUES. STORMS ARE APPROACHING THE TOLEDO AREA AND HEAVY
RAIN LOOKS TO IMPACT AT LEAST THE EARLY PORTION OF THE MORNING
COMMUTE. IT APPEARS THESE THUNDERSTORMS HAVE DEVELOPED IN AN AREA
OF MOISTURE CONVERGENCE AHEAD OF THE UPPER LEVEL CIRCULATION.
PREVIOUS DISCUSSION...WATER VAPOR IMAGERY STILL SHOWS AN UPPER
LEVEL CIRCULATION CENTERED OVER SOUTHERN LAKE MICHIGAN EARLY THIS
MORNING. A FEW THUNDERSTORMS HAVE BEEN DEVELOPING EARLY THIS
MORNING ACROSS INDIANA AND NW OHIO AHEAD OF THE DRIER AIR WRAPPING
AROUND THE SOUTH SIDE OF THE CIRCULATION. THE RUC SHOWS THIS SPOKE
OF ENERGY WILL TEND TO WEAKEN OVER THE NEXT SEVERAL HOURS. AFTER
THAT MODELS SHOWS THE UPPER LEVEL FEATURE WEAKENING AND SLOWLY
LIFTING NE ACROSS LOWER MICHIGAN THROUGH THE AFTERNOON. EXPECT TO
SEE THE EARLY MORNING CONVECTION IN THE WEST TEND TO WEAKEN
THROUGH 13-14Z THEN WAIT FOR INSTABILITY TO INCREASE THIS
AFTERNOON. COVERAGE OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO BE
LESS THAN THE PAST COUPLE DAYS GIVEN THE WEAKENING UPPER LEVEL
FEATURE. SUFFICIENT INSTABILITY IS EXPECTED TO DEVELOP AGAIN THIS
AFTERNOON WITH POCKETS OF CAPE IN EXCESS OF 2000 J/KG. THERE WILL
BE LESS OF A TRIGGER THIS AFTERNOON WITH BEST CHANCES FOR
INITIATION IN NW OHIO ON THE SOUTHERN FLANK OF THE WAVE AND NE
OHIO ALONG THE LAKE BREEZE. ALTHOUGH SEVERE THUNDERSTORMS ARE
GENERALLY NOT EXPECTED...CAN NOT RULE OUT A WARNING OR TWO AS
STRONG CELLS COLLAPSE. NOT ENOUGH SHEAR FOR ANYTHING MORE
ORGANIZED TODAY.
WITH LESS CLOUD COVER AND PRECIP THAN YESTERDAY...TEMPERATURES WILL
REBOUND INTO THE MID 80S IN PA TO NEAR 90 IN NW OHIO.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
THUNDERSTORMS WILL DIMINISH THIS EVENING WITH HEIGHTS BUILDING ALOFT
ON SUNDAY. THE TREND WILL CONTINUE FOR LESS THUNDERSTORM ACTIVITY
EXCEPT FOR NE OHIO/NW PA WHERE THUNDERSTORMS WILL LIKELY DEVELOP
AGAIN ALONG THE LAKE BREEZE. DEWPOINTS START TO MIX OUT BY MONDAY
AND EXPECT DRY CONDITIONS TO FINALLY PREVAIL WITH THE ATMOSPHERE
BECOMING INCREASINGLY CAPPED.
THE RIDGE ALOFT STARTS TO FLATTEN BY TUESDAY AS THE UPPER TROUGH
APPROACHES THE MIDWEST. GFS IS STILL MORE AGGRESSIVE WITH SHORTWAVE
ENERGY STREAMING NORTHEAST THROUGH THE CENTRAL GREAT LAKES ON
TUESDAY AFTERNOON AHEAD OF THE TROUGH WITH THUNDERSTORMS DEVELOPING.
THE GFS IS AN OUTLIER WITH THIS ENERGY AND OUTPACES THE RETURN OF
THE LOW-LEVEL MOISTURE. EXPECT CONVECTION TO FILL IN TUESDAY NIGHT
AS THE SLOW MOVING FRONTAL BOUNDARY SINKS SOUTH. GIVEN THE SLOWER
TIMING...KEPT HIGHS IN THE UPPER 80S TO NEAR 90 THROUGH TUESDAY.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
BOTH MODELS SIGNALING
CHANGE OF THE CURRENT WEATHER PATTERN MID WEEK. UNFORTUNATELY THE
ECMWF IS COMING INTO LINE WITH THE LATEST GFS. ALTHOUGH GFS A
LITTLE FASTER ON THE TIMING TREND IS STILL THE SAME. MODELS PUSH
COLD FRONT ACROSS THE FORECAST AREA ON WEDNESDAY ONLY TO STALL THE
FRONT ACROSS CENTRAL OHIO...WITH LOW PRESSURE MOVING ACROSS THE
LOWER LAKES BY THE END OF THE WORK WEEK. MEANWHILE AT THE UPPER
LEVELS NICE UPPER RIDGE WILL GRADUALLY BE REPLACED BY A DIGGING
TROUGH BY THIS TIME NEXT WEEK.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
CONVECTION FROM NW OH INTO THE WESTERN BASIN WILL DISSIPATE BY MID
MORNING. EXPECT ISOLATED TO SCATTED TSRA TO REDEVELOP LATE THIS
AFTERNOON. BEST CHANCE AGAIN APPEARS TO BE NW OHIO. ADDED VCTS
LATE THIS AFTERNOON FOR TOL AND FDY.
OUTLOOK...AREAS OF NON VFR EACH MORNING IN FOG AND HAZE.
&&
.MARINE...
QUIET WEATHER WILL CONTINUE ON THE LAKE THROUGH THE
WEEKEND...ALTHOUGH A CHANCE OF THUNDERSTORM ACTIVITY IS POSSIBLE
THIS AFTERNOON. SOUTHWEST FLOW WILL DEVELOP ON THE LAKE EARLY IN
THE WORK WEEK AHEAD OF SLOW MOVING COLD FRONT. MODELS CONTINUE TO
HOLD OFF THE NEXT FRONT UNTIL WEDNESDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KEC
NEAR TERM...KEC
SHORT TERM...KEC
LONG TERM...DJB
AVIATION...DJB
MARINE...DJB
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
648 AM EDT SAT SEP 5 2015
.SYNOPSIS...
THE UPPER LEVEL DISTURBANCE OVER MICHIGAN WILL WEAKEN AND LIFT
NORTHEAST TODAY. A BROAD AREA OF HIGH PRESSURE OVER NEW ENGLAND WILL
MOVE SOUTH ALONG THE EAST COAST THROUGH THE HOLIDAY WEEKEND. A
WEAKENING FRONT WILL STALL JUST NORTH OF THE AREA ON TUESDAY...THEN
PUSH SOUTH ON WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CLUSTER OF THUNDERSTORMS WITH EFFICIENT RAINFALL RATES DEVELOPED
OVER THE LAST 2 HOURS PRODUCING HEAVY RAINFALL FROM VANLUE TO
FOSTORIA TO NEAR WOODVILLE. STORM MOTION IS VERY SLOW WITH STORMS
BUILDING TO NORTH AT 5-10 MPH. RADAR ESTIMATES THAT SOME AREAS
HAVE ALREADY HAD OVER 2 INCHES OF RAIN AND ARE MONITORING FOR ANY
FLOODING ISSUES. STORMS ARE APPROACHING THE TOLEDO AREA AND HEAVY
RAIN LOOKS TO IMPACT AT LEAST THE EARLY PORTION OF THE MORNING
COMMUTE. IT APPEARS THESE THUNDERSTORMS HAVE DEVELOPED IN AN AREA
OF MOISTURE CONVERGENCE AHEAD OF THE UPPER LEVEL CIRCULATION.
PREVIOUS DISCUSSION...WATER VAPOR IMAGERY STILL SHOWS AN UPPER
LEVEL CIRCULATION CENTERED OVER SOUTHERN LAKE MICHIGAN EARLY THIS
MORNING. A FEW THUNDERSTORMS HAVE BEEN DEVELOPING EARLY THIS
MORNING ACROSS INDIANA AND NW OHIO AHEAD OF THE DRIER AIR WRAPPING
AROUND THE SOUTH SIDE OF THE CIRCULATION. THE RUC SHOWS THIS SPOKE
OF ENERGY WILL TEND TO WEAKEN OVER THE NEXT SEVERAL HOURS. AFTER
THAT MODELS SHOWS THE UPPER LEVEL FEATURE WEAKENING AND SLOWLY
LIFTING NE ACROSS LOWER MICHIGAN THROUGH THE AFTERNOON. EXPECT TO
SEE THE EARLY MORNING CONVECTION IN THE WEST TEND TO WEAKEN
THROUGH 13-14Z THEN WAIT FOR INSTABILITY TO INCREASE THIS
AFTERNOON. COVERAGE OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO BE
LESS THAN THE PAST COUPLE DAYS GIVEN THE WEAKENING UPPER LEVEL
FEATURE. SUFFICIENT INSTABILITY IS EXPECTED TO DEVELOP AGAIN THIS
AFTERNOON WITH POCKETS OF CAPE IN EXCESS OF 2000 J/KG. THERE WILL
BE LESS OF A TRIGGER THIS AFTERNOON WITH BEST CHANCES FOR
INITIATION IN NW OHIO ON THE SOUTHERN FLANK OF THE WAVE AND NE
OHIO ALONG THE LAKE BREEZE. ALTHOUGH SEVERE THUNDERSTORMS ARE
GENERALLY NOT EXPECTED...CAN NOT RULE OUT A WARNING OR TWO AS
STRONG CELLS COLLAPSE. NOT ENOUGH SHEAR FOR ANYTHING MORE
ORGANIZED TODAY.
WITH LESS CLOUD COVER AND PRECIP THAN YESTERDAY...TEMPERATURES WILL
REBOUND INTO THE MID 80S IN PA TO NEAR 90 IN NW OHIO.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
THUNDERSTORMS WILL DIMINISH THIS EVENING WITH HEIGHTS BUILDING ALOFT
ON SUNDAY. THE TREND WILL CONTINUE FOR LESS THUNDERSTORM ACTIVITY
EXCEPT FOR NE OHIO/NW PA WHERE THUNDERSTORMS WILL LIKELY DEVELOP
AGAIN ALONG THE LAKE BREEZE. DEWPOINTS START TO MIX OUT BY MONDAY
AND EXPECT DRY CONDITIONS TO FINALLY PREVAIL WITH THE ATMOSPHERE
BECOMING INCREASINGLY CAPPED.
THE RIDGE ALOFT STARTS TO FLATTEN BY TUESDAY AS THE UPPER TROUGH
APPROACHES THE MIDWEST. GFS IS STILL MORE AGGRESSIVE WITH SHORTWAVE
ENERGY STREAMING NORTHEAST THROUGH THE CENTRAL GREAT LAKES ON
TUESDAY AFTERNOON AHEAD OF THE TROUGH WITH THUNDERSTORMS DEVELOPING.
THE GFS IS AN OUTLIER WITH THIS ENERGY AND OUTPACES THE RETURN OF
THE LOW-LEVEL MOISTURE. EXPECT CONVECTION TO FILL IN TUESDAY NIGHT
AS THE SLOW MOVING FRONTAL BOUNDARY SINKS SOUTH. GIVEN THE SLOWER
TIMING...KEPT HIGHS IN THE UPPER 80S TO NEAR 90 THROUGH TUESDAY.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
BOTH MODELS SIGNALING
CHANGE OF THE CURRENT WEATHER PATTERN MID WEEK. UNFORTUNATELY THE
ECMWF IS COMING INTO LINE WITH THE LATEST GFS. ALTHOUGH GFS A
LITTLE FASTER ON THE TIMING TREND IS STILL THE SAME. MODELS PUSH
COLD FRONT ACROSS THE FORECAST AREA ON WEDNESDAY ONLY TO STALL THE
FRONT ACROSS CENTRAL OHIO...WITH LOW PRESSURE MOVING ACROSS THE
LOWER LAKES BY THE END OF THE WORK WEEK. MEANWHILE AT THE UPPER
LEVELS NICE UPPER RIDGE WILL GRADUALLY BE REPLACED BY A DIGGING
TROUGH BY THIS TIME NEXT WEEK.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
LITTLE CHANGE IN WEATHER PATTERN. AREAS OF MVFR BR TOWARD
DAYBREAK WITH ISOLATED CONVECTION THIS AFTERNOON. DO NOT THINK
THERE WILL BE AS MUCH CONVECTION THIS AFTERNOON AS YDY.
OUTLOOK...AREAS OF NON VFR EACH MORNING IN FOG AND HAZE.
&&
.MARINE...
QUIET WEATHER WILL CONTINUE ON THE LAKE THROUGH THE
WEEKEND...ALTHOUGH A CHANCE OF THUNDERSTORM ACTIVITY IS POSSIBLE
THIS AFTERNOON. SOUTHWEST FLOW WILL DEVELOP ON THE LAKE EARLY IN
THE WORK WEEK AHEAD OF SLOW MOVING COLD FRONT. MODELS CONTINUE TO
HOLD OFF THE NEXT FRONT UNTIL WEDNESDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KEC
NEAR TERM...KEC
SHORT TERM...KEC
LONG TERM...DJB
AVIATION...DJB
MARINE...DJB
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
425 AM EDT SAT SEP 5 2015
.SYNOPSIS...
THE UPPER LEVEL DISTURBANCE OVER MICHIGAN WILL WEAKEN AND LIFT
NORTHEAST TODAY. A BROAD AREA OF HIGH PRESSURE OVER NEW ENGLAND WILL
MOVE SOUTH ALONG THE EAST COAST THROUGH THE HOLIDAY WEEKEND. A
WEAKENING FRONT WILL STALL JUST NORTH OF THE AREA ON TUESDAY...THEN
PUSH SOUTH ON WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WATER VAPOR IMAGERY STILL SHOWS AN UPPER LEVEL CIRCULATION CENTERED
OVER SOUTHERN LAKE MICHIGAN EARLY THIS MORNING. A FEW THUNDERSTORMS
HAVE BEEN DEVELOPING EARLY THIS MORNING ACROSS INDIANA AND NW OHIO
AHEAD OF THE DRIER AIR WRAPPING AROUND THE SOUTH SIDE OF THE
CIRCULATION. THE RUC SHOWS THIS SPOKE OF ENERGY WILL TEND TO WEAKEN
OVER THE NEXT SEVERAL HOURS. AFTER THAT MODELS SHOWS THE UPPER LEVEL
FEATURE WEAKENING AND SLOWLY LIFTING NE ACROSS LOWER MICHIGAN
THROUGH THE AFTERNOON. EXPECT TO SEE THE EARLY MORNING CONVECTION IN
THE WEST TEND TO WEAKEN THROUGH 13-14Z THEN WAIT FOR INSTABILITY TO
INCREASE THIS AFTERNOON. COVERAGE OF SHOWERS AND THUNDERSTORMS IS
EXPECTED TO BE LESS THAN THE PAST COUPLE DAYS GIVEN THE WEAKENING
UPPER LEVEL FEATURE. SUFFICIENT INSTABILITY IS EXPECTED TO DEVELOP
AGAIN THIS AFTERNOON WITH POCKETS OF CAPE IN EXCESS OF 2000 J/KG.
THERE WILL BE LESS OF A TRIGGER THIS AFTERNOON WITH BEST CHANCES FOR
INITIATION IN NW OHIO ON THE SOUTHERN FLANK OF THE WAVE AND NE OHIO
ALONG THE LAKE BREEZE.
WITH LESS CLOUD COVER AND PRECIP THAN YESTERDAY...TEMPERATURES WILL
REBOUND INTO THE MID 80S IN PA TO NEAR 90 IN NW OHIO.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
THUNDERSTORMS WILL DIMINISH THIS EVENING WITH HEIGHTS BUILDING ALOFT
ON SUNDAY. THE TREND WILL CONTINUE FOR LESS THUNDERSTORM ACTIVITY
EXCEPT FOR NE OHIO/NW PA WHERE THUNDERSTORMS WILL LIKELY DEVELOP
AGAIN ALONG THE LAKE BREEZE. DEWPOINTS START TO MIX OUT BY MONDAY
AND EXPECT DRY CONDITIONS TO FINALLY PREVAIL WITH THE ATMOSPHERE
BECOMING INCREASINGLY CAPPED.
THE RIDGE ALOFT STARTS TO FLATTEN BY TUESDAY AS THE UPPER TROUGH
APPROACHES THE MIDWEST. GFS IS STILL MORE AGGRESSIVE WITH SHORTWAVE
ENERGY STREAMING NORTHEAST THROUGH THE CENTRAL GREAT LAKES ON
TUESDAY AFTERNOON AHEAD OF THE TROUGH WITH THUNDERSTORMS DEVELOPING.
THE GFS IS AN OUTLIER WITH THIS ENERGY AND OUTPACES THE RETURN OF
THE LOW-LEVEL MOISTURE. EXPECT CONVECTION TO FILL IN TUESDAY NIGHT
AS THE SLOW MOVING FRONTAL BOUNDARY SINKS SOUTH. GIVEN THE SLOWER
TIMING...KEPT HIGHS IN THE UPPER 80S TO NEAR 90 THROUGH TUESDAY.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
BOTH MODELS SIGNALING
CHANGE OF THE CURRENT WEATHER PATTERN MID WEEK. UNFORTUNATELY THE
ECMWF IS COMING INTO LINE WITH THE LATEST GFS. ALTHOUGH GFS A
LITTLE FASTER ON THE TIMING TREND IS STILL THE SAME. MODELS PUSH
COLD FRONT ACROSS THE FORECAST AREA ON WEDNESDAY ONLY TO STALL THE
FRONT ACROSS CENTRAL OHIO...WITH LOW PRESSURE MOVING ACROSS THE
LOWER LAKES BY THE END OF THE WORK WEEK. MEANWHILE AT THE UPPER
LEVELS NICE UPPER RIDGE WILL GRADUALLY BE REPLACED BY A DIGGING
TROUGH BY THIS TIME NEXT WEEK.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
LITTLE CHANGE IN WEATHER PATTERN. AREAS OF MVFR BR TOWARD
DAYBREAK WITH ISOLATED CONVECTION THIS AFTERNOON. DO NOT THINK
THERE WILL BE AS MUCH CONVECTION THIS AFTERNOON AS YDY.
OUTLOOK...AREAS OF NON VFR EACH MORNING IN FOG AND HAZE.
&&
.MARINE...
QUIET WEATHER WILL CONTINUE ON THE LAKE THROUGH THE
WEEKEND...ALTHOUGH A CHANCE OF THUNDERSTORM ACTIVITY IS POSSIBLE
THIS AFTERNOON. SOUTHWEST FLOW WILL DEVELOP ON THE LAKE EARLY IN
THE WORK WEEK AHEAD OF SLOW MOVING COLD FRONT. MODELS CONTINUE TO
HOLD OFF THE NEXT FRONT UNTIL WEDNESDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KEC
NEAR TERM...KEC
SHORT TERM...KEC
LONG TERM...DJB
AVIATION...DJB
MARINE...DJB
AREA FORECAST DISCUSSION
NWS PORTLAND OR
257 PM PDT SAT SEP 5 2015
.SYNOPSIS...AN UPPER LEVEL TROUGH WILL MOVE EAST OF THE CASCADES
TODAY WITH SHOWERS OVER THE CASCADES GRADUALLY ENDING. A WEAK FRONT
WILL BRING SOME LIGHT RAIN TO THE COAST OVERNIGHT SATURDAY...AND
POSSIBLY NORTHERN INLAND AREAS SUNDAY AFTERNOON. DRY WEATHER IS
EXPECTED FOR LABOR DAY. ANOTHER WEAK FRONT MAY BRING LIGHT RAIN TO
AREAS NORTH OF THE COLUMBIA RIVER TUESDAY MORNING. AN UPPER LEVEL
RIDGE SHOULD KEEP THE NEXT APPROACHING DISTURBANCES NORTH OF THE
AREA THEREAFTER WITH WARMING TEMPERATURES THROUGH THE REMAINDER OF
THE WEEK.
&&
.SHORT TERM...THE UPPER TROUGH HAS SHIFTED WELL EAST OF THE CASCADES
TODAY WITH THE NEXT DISTURBANCE PRESENTLY LOCATED OFF THE NORTHERN
END OF VANCOUVER ISLAND. AS OF 2 PM PDT...NWS DOPPLER RADAR DEPICTS
WIDESPREAD SHOWERS ACROSS THE NORTHERN PORTION OF THE FORECAST
AREA...NORTH OF A ROUGHLY PACIFIC CITY TO SALEM LINE. SURFACE
ANALYSIS REVEALS A WEAK WARM FRONT ALIGNED NORTH TO SOUTH NEAR THE
COAST...THE LIKELY CAUSE FOR SOME WEAK FORCED ASCENT THAT IS TAPPING
INTO WEAK INSTABILITY TO CREATE SCATTERED SHOWERS ACROSS MUCH OF THE
NORTHERN PORTION OF THE FORECAST AREA THIS AFTERNOON. KRTX DOPPLER
RADAR DEPICTS THESE SHOWERS REMAINING GENERALLY NORTH OF A PACIFIC
CITY TO SALEM LINE. EXPECT THESE SHOWERS TO CONTINUE INTO THIS
EVENING BUT TAPER OFF FROM WEST TO EAST.
MEANWHILE...LATEST VISIBLE SATELLITE IMAGERY AND OBSERVATIONS DEPICT
THE MAIN SURFACE FRONT APPROACHING THE NORTHERN SIDE OF VANCOUVER
ISLAND AT THIS TIME. SURFACE ANALYSIS REVEALS A HIGHLY KINKED SURFACE
COLD FRONT...LENDING SOME ADDITIONAL UNCERTAINTY IN TIMING THE
PROGRESS OF THE SYSTEM. ADDITIONALLY...A FEW OF THE HIGH-RES MODELS
SUGGEST A FASTER PROGRESSION...WHILE THE 12Z SUITE OF LARGER SCALE
MODELS REMAIN FAIRLY IN LINE WITH PREVIOUS RUNS. NUDGED THE TIMING OF
INCREASED POPS A FEW HOURS EARLIER IN A BIT OF COMPROMISE. HAVE A
HARD TIME COMING ALL THE WAY UP TO THE HRRR TIMING GIVEN SOME
DISCREPANCIES IN THE BETWEEN MOISTURE AND WIND FIELDS.
NONETHELESS...INCREASING CLOUDS WILL MOVE INTO INTO THE NORTH COAST
TONIGHT AND PUSH INLAND. EXPECT MORE PROMINENT RAIN INTO THE COAST BY
AROUND 11 PM AND INLAND SUNDAY MORNING. STILL THINK HIGHEST QPF WILL
BE ALONG THE NORTHERN COAST AND COAST RANGE...BUT LATEST MODEL TRENDS
GIVE A LITTLE REASON TO SUGGEST SOME WIDESPREAD MEASURABLE RAIN IN
THE NORTHERN INTERIOR TOO...PARTICULARLY WITH A SWATH OF MOISTURE
EVIDENT IN LATEST WATER VAPOR IMAGERY WITH PW VALUES IN EXCESS OF ONE
INCH. THIS REMAINS THE LOWEST CONFIDENCE OF THE FORECAST
PERIOD...ALONG WITH THE PRECISE TIMING OF THE ARRIVAL OF THE FRONT.
ASSOCIATED CLOUDINESS SHOULD KEEP TEMPERATURES AROUND 70 DEGREES
INLAND FROM SALEM NORTHWARD...BUT FEWER CLOUDS SOUTH COULD LET EUGENE
WARM INTO THE MID 70S.
SHORTWAVE TROUGH PASSES THROUGH THE AREA WITH HEIGHTS RISING SUNDAY
NIGHT INTO MONDAY. THIS WILL BRING DRY WEATHER AND SLIGHTLY WARMER
TEMPERATURES FOR THE LABOR DAY HOLIDAY. ANOTHER DISTURBANCE MOVES
INTO SOUTHERN B.C. ON TUESDAY BUT WITH A STRENGTHENING UPPER RIDGE
SUSPECT THE PRIMARY IMPACT WILL BE SOME ADDITIONAL CLOUDS MOST RAIN
REMAINS NORTH OF THE AREA EXCEPT FOR PERHAPS SOME LIGHT DRIZZLE
NORTHER OF THE COLUMBIA RIVER LATER TUE AFTERNOON. CULLEN
.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY. UPPER LEVEL RIDGE KEEPS
THE STORM TRACK NORTH OF OUR AREA THROUGH AT LEAST SATURDAY. THIS
WILL KEEP OUR AREA DRY...AND WILL WARM INLAND TEMPERATURES INTO THE
LOW 80S BY WEDNESDAY. WINDS SHIFT MORE OFFSHORE LATE IN THE
WEEK...WHICH WILL ALLOW TEMPERATURES TO GET INTO THE MIDDLE OR MAYBE
UPPER 80S BY SATURDAY. ALONG THE COAST...TEMPERATURES GET INTO THE
LOW 70S BY WEDNESDAY...AND REMAIN ABOVE SEASONAL NORMAL THROUGH
SATURDAY. -MCCOY
&&
.AVIATION...A WEAK DISTURBANCE IS CURRENTLY MOVING ACROSS THE
REGION BRINGING AN INCREASE IN CLOUD COVER AND SOME SCATTERED
SHOWERS. THE MAIN FRONTAL SYSTEM WILL MOVE ACROSS THE REGION LATE
TONIGHT THROUGH SUNDAY MORNING. CONDITIONS LOOK TO REMAIN MOSTLY
VFR THROUGH TONIGHT. THE COAST WILL LIKELY LOWER TOWARDS
MVFR...AND POSSIBLY IFR...BETWEEN 06-10Z. THE INTERIOR LOOKS TO
REMAIN VFR...BUT BRIEF PERIODS OF REDUCED CIGS AND VSBY MAY BE
POSSIBLE UNDER HEAVIER RAIN BANDS AFTER 10Z. RAIN ACTIVITY AND
CLOUD COVER SHOULD DECREASE LATE SUNDAY.
KPDX AND APPROACHES...VFR THROUGH TONIGHT. SCATTERED SHOWERS
CONTINUE THROUGH THIS EVENING. CLOUD COVER AND RAIN CHANCES
INCREASE AFTER 10Z...WITH REDUCED CIGS AND VSBY POSSIBLE UNDER
HEAVIER RAIN BANDS. /64
&&
.MARINE...BENIGN WINDS AND SEAS CONTINUE THROUGH EARLY NEXT WEEK.
A WEAK FRONT MOVING ACROSS THE WATERS EARLY SUNDAY MORNING WILL
BRING A FEW HOURS OF SOUTHERLY WINDS...BUT WINDS SHOULD GENERALLY
REMAIN UNDER 20 KT. A FEW GUSTS TO 25 KT POSSIBLE UNDER HEAVIER
RAIN BANDS. HIGH PRESSURE REBUILDING OVER THE NORTHEAST PACIFIC
AND THERMAL LOW PRESSURE STRENGTHENING OVER SOUTHERN OREGON SHOULD
BRING GUSTY AFTERNOON/EVENING WINDS TO THE CENTRAL OREGON WATERS
THROUGH THE UPCOMING WEEK...WITH SOLID ADVISORY GUSTS DEVELOPING
LATE IN THE WEEK. A FEW WEAK DISTURBANCE MAY BRUSH THE NORTHERN
WATERS EARLY NEXT WEEK...BUT IMPACTS REMAIN MINIMAL.
SEAS REMAIN AROUND 4 TO 6 FT THROUGH MUCH OF THE UPCOMING WEEK.
MAY SEE SEAS CLIMB ABOVE 7 FT LATE NEXT WEEK...BUT CONFIDENCE IS
LOW. /64
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...NONE.
&&
$$
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
731 AM EDT SAT SEP 5 2015
.SYNOPSIS...
HIGH PRESSURE WILL ENSURE MAINLY DRY WEATHER FOR LABOR DAY
WEEKEND WITH ABOVE NORMAL WARMTH AND JUST THE CHANCE OF AN
AFTERNOON OR EVENING POP-UP SHOWER OR THUNDERSTORM. THE PATTERN
WILL START TO CHANGE IN THE MIDDLE OF THE WEEK AS THE UPPER LEVEL
FLOW FLATTENS OUT AND A COLD FRONT DROPS DOWN FROM THE NORTH.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SHOWERS HAVE BEEN PERSISTENT IN THE SRN TIER THROUGH THE NIGHT.
THE WIND SHIFT/WEAK CONVERGENCE AND DEEP EASTERLY MOISTURE INFLUX
ARE PROBABLY DRIVING THESE SHOWERS SINCE DIURNAL INSTABILITY HAS
LONG SINCE DISAPPEARED. ONLY LIGHT SHOWERS /NO T/ LEFT IN THE SC
MTNS. HRRR AND RAP MOVE THESE SLIGHTLY TO THE WEST BEFORE KILLING
THEM OFF JUST AFTER SUNRISE. LOW CLOUDS HAVE OVERSPREAD/DEVELOPED
OVER THE ENTIRE REGION EXCEPT FOR WARREN CO. A FEW PATCHES OF
CLEAR EAST OF KIPT CAN BE IMAGINED WHEN PERUSING THE 11-3.9
MICRON IMAGERY THIS MORNING. OTHERWISE...IT IS CLOUDY. THESE
CLOUDS COULD BE TOUGH TO MIX OUT - AT LEAST IN A RAPID FASHION -
SINCE THEY ARE GENERALLY ABOVE 1KFT. THUS...WILL HANG ONTO SOME OF
THESE CLOUDS INTO THE MID TO LATE MORNING. THE EAST WILL BE
BREAKING OUT INTO THE SUN AND THE MIXING IN THE WEST COULD ALLOW A
SHOWER OR TWO TO DEVELOP IN THE AFTN. HOWEVER...MOST OF THESE WILL
REMAIN WEST OF THE CWA. ONLY THE NW IS WORTHY OF A CHC POP FOR
LATE THIS AFTN/THIS EVENING AS A LAKE BREEZE MAY KICK OFF A FEW
SHRA. THE CLOUDS WILL MAKE IT MORE DIFFICULT TO GET TO THE LOFTY
MAXES WE HAVE EXPERIENCED RECENTLY - INCLUDING TIES OF THE RECORD
HIGHS AT HARRISBURG...ALTOONA AND BRADFORD YESTERDAY. WILL GO FOR
MAXES BASED ON AN EQUAL BLEND OF MOS GUIDANCE MINUS ONE OR TWO
DEGS. THIS WILL RESULT IN ONLY A 10 DEGREE DIURNAL SWING AT MANY
PLACES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
THE UPPER LOW OVER THE UPPER GREAT LAKES WILL SLOLY FILL AND LOSE
CHARACTER. THE SFC HIGH WILL STILL NOSE INTO THE STATE...BUT THE
CENTER OF IT WILL SLIDE SOUTH INTO THE WESTERN ATLANTIC BY
MONDAY. ANY SHOWERS THIS EVENING WILL LIKELY BE IN THE NW...BUT
THE EXPECTED CELL MOTION SHOULD KEEP THEM EITHER OUT OF THE STATE
TO THE NORTH OR MAKE THE FEW THAT DO POP UP GO SLOWLY TO THE NORTH
AND OUT OF THE AREA EARLY THIS EVENING. THE LOW CLOUDS WILL
PROBABLY TRY TO REDEVELOP IN THE ERN MTNS. OTHER AREAS MAY SEE
THEM TRY TO FORM...BUT WILL KEEP IT GENERALLY P/C OVERNIGHT WITH
THE CLEARING PERHAPS ALLOWING FOR SOME MORNING FOG ON SUNDAY.
SUNDAY LOOKS TO BE DRIER AND SUNNIER...AND POPS ALMOST NON-
EXISTENT. TEMPS WILL GET A FEW DEGS F WARMER VS SATURDAY. ONCE
AGAIN...IT WILL BE THE FAR NW WHICH COULD SEE A POP UP SHOWER -
PERHAPS AGAIN BEING GENERATED ALONG A LAKE BREEZE BOUNDARY.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
THE HIGH PRESSURE WILL KEEP IT WARM AND MAINLY DRY INTO MONDAY.
A WEAK COLD FRONT WILL SLIDE SLOWLY TO THE ESE FROM THE GREAT
LAKES/MIDWEST STATES. THIS FEATURE COULD BRING SOME ISOLATED
SHRA/TSRA TO OUR NW ZONES BEGINNING TUESDAY AFTERNOON AND EVENING.
A SLOWLY AMPLIFYING BROAD TROUGH FROM THE NRN PLAINS THROUGH THE
NE U.S. WEDNESDAY AFTERNOON INTO NEXT WEEKEND WILL PUSH A
SECOND...STRONGER CFRONT EAST ACROSS THE COMMONWEALTH WEDNESDAY
NIGHT AND THURSDAY.
THIS PATTERN TRANSITION WILL BRING A FEW OPPORTUNITIES FOR
SHOWERS AND THUNDERSTORMS...ALBEIT MAINLY OF THE SCATTERED
AFTERNOON AND EVENING VARIETY.
12Z GEFS AND 12Z EC ARE IN GOOD AGREEMENT ON THE LOCATION OF THIS
TROUGH AXIS /FROM LAKE SUPERIOR TO THE MID MISS VALLEY AT 00Z
SAT/...THOUGH AS ONE WOULD EXPECT...THE ENSEMBLE MEAN DAMPENS OUT
THE AMPLITUDE OF THE TROUGH COMPARED TO THE EC.
DETAILS IN THE TIMING OF ANY SPECIFIC SHORTWAVES ROTATING THROUGH
THIS AMPLIFYING TROUGH ARE SIMPLY TOO MUDDY AT THIS TIME RANGE.
ONE THING MORE CERTAIN IN THIS MEDIUM RANGE FORECAST IS THE COOLING
TEMPS FOR THE LATTER HALF OF THE WEEK AND NEXT WEEKEND...WHEN BOTH
MAX AND MIN TEMPS COULD BE UP TO SEVERAL DEG F BELOW NORMAL
/ESPECIALLY OVER THE NRN AND WESTERN MTNS OF THE STATE...WHERE MORE
CLOUDS AND COOLER TEMPS ALOFT WILL BE FOUND/.
&&
.AVIATION /11Z SATURDAY THROUGH WEDNESDAY/...
11.3.9U IMAGERY AT 11Z SHOWS STRATUS HAS BECOME WIDESPREAD ACROSS
CENTRAL PA...THE RESULT OF MOIST SERLY FLOW AND OROGRAPHIC
LIFTING. BLEND OF LATEST HRRR/SFC OBS SUGGEST IFR CIGS ARE LIKELY
BTWN 12Z-13Z AT KBFD/KJST AND POSSIBLE AT KAOO. LOWER ELEVATIONS
FURTHER EAST SHOULD FARE BETTER WITH MVFR CIGS EXPECTED.
DIURNAL HEATING/MIXING WILL CAUSE CIGS TO RISE BY LATE AM. MDL
SOUNDINGS INDICATE MVFR CIGS MAY LINGER ACROSS THE CENTRAL MTNS
UNTIL ARND NOON. HOWEVER...BY AFTN THERE IS A HIGH DEGREE OF
CONFIDENCE IN WIDESPREAD VFR CONDS AND LIGHT WIND.
MOSTLY CLEAR SKIES AND A LIGHT WIND WILL LIKELY RESULT IN PATCHY
VALLEY FOG AGAIN EARLY SUNDAY MORNING.
OUTLOOK...
SUN-TUE...PATCHY FOG IN THE MORNING...OTHERWISE VFR.
WED...ISOLD PM TSRA IMPACTS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...LAMBERT
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
504 AM EDT SAT SEP 5 2015
.SYNOPSIS...
HIGH PRESSURE WILL ENSURE MAINLY DRY WEATHER FOR LABOR DAY
WEEKEND WITH ABOVE NORMAL WARMTH AND JUST THE CHANCE OF AN
AFTERNOON OR EVENING POP-UP SHOWER OR THUNDERSTORM. THE PATTERN
WILL START TO CHANGE IN THE MIDDLE OF THE WEEK AS THE UPPER LEVEL
FLOW FLATTENS OUT AND A COLD FRONT DROPS DOWN FROM THE NORTH.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SHOWERS HAVE BEEN PERSISTENT IN THE SRN TIER THROUGH THE NIGHT.
THE WIND SHIFT/WEAK CONVERGENCE AND DEEP EASTERLY MOISTURE INFLUX
ARE PROBABLY DRIVING THESE SHOWERS SINCE DIURNAL INSTABILITY HAS
LONG SINCE DISAPPEARED. ONLY LIGHT SHOWERS /NO T/ LEFT IN THE SC
MTNS. HRRR AND RAP MOVE THESE SLIGHTLY TO THE WEST BEFORE KILLING
THEM OFF JUST AFTER SUNRISE. LOW CLOUDS HAVE OVERSPREAD/DEVELOPED
OVER THE ENTIRE REGION EXCEPT FOR WARREN CO. A FEW PATCHES OF
CLEAR EAST OF KIPT CAN BE IMAGINED WHEN PERUSING THE 11-3.9
MICRON IMAGERY THIS MORNING. OTHERWISE...IT IS CLOUDY. THESE
CLOUDS COULD BE TOUGH TO MIX OUT - AT LEAST IN A RAPID FASHION -
SINCE THEY ARE GENERALLY ABOVE 1KFT. THUS...WILL HANG ONTO SOME OF
THESE CLOUDS INTO THE MID TO LATE MORNING. THE EAST WILL BE
BREAKING OUT INTO THE SUN AND THE MIXING IN THE WEST COULD ALLOW A
SHOWER OR TWO TO DEVELOP IN THE AFTN. HOWEVER...MOST OF THESE WILL
REMAIN WEST OF THE CWA. ONLY THE NW IS WORTHY OF A CHC POP FOR
LATE THIS AFTN/THIS EVENING AS A LAKE BREEZE MAY KICK OFF A FEW
SHRA. THE CLOUDS WILL MAKE IT MORE DIFFICULT TO GET TO THE LOFTY
MAXES WE HAVE EXPERIENCED RECENTLY - INCLUDING TIES OF THE RECORD
HIGHS AT HARRISBURG...ALTOONA AND BRADFORD YESTERDAY. WILL GO FOR
MAXES BASED ON AN EQUAL BLEND OF MOS GUIDANCE MINUS ONE OR TWO
DEGS. THIS WILL RESULT IN ONLY A 10 DEGREE DIURNAL SWING AT MANY
PLACES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
THE UPPER LOW OVER THE UPPER GREAT LAKES WILL SLOLY FILL AND LOSE
CHARACTER. THE SFC HIGH WILL STILL NOSE INTO THE STATE...BUT THE
CENTER OF IT WILL SLIDE SOUTH INTO THE WESTERN ATLANTIC BY
MONDAY. ANY SHOWERS THIS EVENING WILL LIKELY BE IN THE NW...BUT
THE EXPECTED CELL MOTION SHOULD KEEP THEM EITHER OUT OF THE STATE
TO THE NORTH OR MAKE THE FEW THAT DO POP UP GO SLOWLY TO THE NORTH
AND OUT OF THE AREA EARLY THIS EVENING. THE LOW CLOUDS WILL
PROBABLY TRY TO REDEVELOP IN THE ERN MTNS. OTHER AREAS MAY SEE
THEM TRY TO FORM...BUT WILL KEEP IT GENERALLY P/C OVERNIGHT WITH
THE CLEARING PERHAPS ALLOWING FOR SOME MORNING FOG ON SUNDAY.
SUNDAY LOOKS TO BE DRIER AND SUNNIER...AND POPS ALMOST NON-
EXISTENT. TEMPS WILL GET A FEW DEGS F WARMER VS SATURDAY. ONCE
AGAIN...IT WILL BE THE FAR NW WHICH COULD SEE A POP UP SHOWER -
PERHAPS AGAIN BEING GENERATED ALONG A LAKE BREEZE BOUNDARY.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
THE HIGH PRESSURE WILL KEEP IT WARM AND MAINLY DRY INTO MONDAY.
A WEAK COLD FRONT WILL SLIDE SLOWLY TO THE ESE FROM THE GREAT
LAKES/MIDWEST STATES. THIS FEATURE COULD BRING SOME ISOLATED
SHRA/TSRA TO OUR NW ZONES BEGINNING TUESDAY AFTERNOON AND EVENING.
A SLOWLY AMPLIFYING BROAD TROUGH FROM THE NRN PLAINS THROUGH THE
NE U.S. WEDNESDAY AFTERNOON INTO NEXT WEEKEND WILL PUSH A
SECOND...STRONGER CFRONT EAST ACROSS THE COMMONWEALTH WEDNESDAY
NIGHT AND THURSDAY.
THIS PATTERN TRANSITION WILL BRING A FEW OPPORTUNITIES FOR
SHOWERS AND THUNDERSTORMS...ALBEIT MAINLY OF THE SCATTERED
AFTERNOON AND EVENING VARIETY.
12Z GEFS AND 12Z EC ARE IN GOOD AGREEMENT ON THE LOCATION OF THIS
TROUGH AXIS /FROM LAKE SUPERIOR TO THE MID MISS VALLEY AT 00Z
SAT/...THOUGH AS ONE WOULD EXPECT...THE ENSEMBLE MEAN DAMPENS OUT
THE AMPLITUDE OF THE TROUGH COMPARED TO THE EC.
DETAILS IN THE TIMING OF ANY SPECIFIC SHORTWAVES ROTATING THROUGH
THIS AMPLIFYING TROUGH ARE SIMPLY TOO MUDDY AT THIS TIME RANGE.
ONE THING MORE CERTAIN IN THIS MEDIUM RANGE FORECAST IS THE COOLING
TEMPS FOR THE LATTER HALF OF THE WEEK AND NEXT WEEKEND...WHEN BOTH
MAX AND MIN TEMPS COULD BE UP TO SEVERAL DEG F BELOW NORMAL
/ESPECIALLY OVER THE NRN AND WESTERN MTNS OF THE STATE...WHERE MORE
CLOUDS AND COOLER TEMPS ALOFT WILL BE FOUND/.
&&
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
11.3.9U IMAGERY AT 09Z SHOWS STRATUS HAS BECOME WIDESPREAD ACROSS
CENTRAL PA...THE RESULT OF MOIST SERLY FLOW AND OROGRAPHIC
LIFTING. BLEND OF LATEST HRRR/SFC OBS SUGGEST IFR CIGS ARE LIKELY
BTWN 09Z-13Z AT KBFD/KJST/KAOO AND POSSIBLE AT KUNV. LOWER
ELEVATIONS FURTHER EAST SHOULD FARE BETTER WITH MVFR CIGS
EXPECTED. WILL HAVE TO WATCH FOR POSSIBILITY OF FOG DEVELOPMENT AT
KLNS ARND DAWN. SOME MDL DATA SUGGESTS SKIES WILL CLEAR ACROSS
THAT PART OF THE STATE ARND 10Z...ALLOWING FOR DEVELOPMENT OF
RADIATION FOG BTWN 10Z-13Z.
DIURNAL HEATING/MIXING WILL CAUSE CIGS TO RISE BY LATE AM. MDL
SOUNDINGS INDICATE MVFR CIGS MAY LINGER ACROSS THE CENTRAL MTNS
UNTIL ARND NOON. HOWEVER...BY AFTN THERE IS A HIGH DEGREE OF
CONFIDENCE IN WIDESPREAD VFR CONDS AND LIGHT WIND.
MOSTLY CLEAR SKIES AND A LIGHT WIND WILL LIKELY RESULT IN PATCHY
VALLEY FOG AGAIN EARLY SUNDAY MORNING.
OUTLOOK...
SUN-TUE...PATCHY FOG IN THE MORNING...OTHERWISE VFR.
WED...ISOLD PM TSRA IMPACTS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...LAMBERT
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
452 AM EDT SAT SEP 5 2015
.SYNOPSIS...
HIGH PRESSURE WILL ENSURE MAINLY DRY WEATHER FOR LABOR DAY
WEEKEND WITH ABOVE NORMAL WARMTH AND JUST THE CHANCE OF AN
AFTERNOON OR EVENING POP-UP SHOWER OR THUNDERSTORM. THE PATTERN
WILL START TO CHANGE IN THE MIDDLE OF THE WEEK AS THE UPPER LEVEL
FLOW FLATTENS OUT AND A COLD FRONT DROPS DOWN FROM THE NORTH.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SHOWERS HAVE BEEN PERSISTENT IN THE SRN TIER THROUGH THE NIGHT.
THE WIND SHIFT/WEAK CONVERGENCE AND DEEP EASTERLY MOISTURE INFLUX
ARE PROBABLY DRIVING THESE SHOWERS SINCE DIURNAL INSTABILITY HAS
LONG SINCE DISAPPEARED. ONLY LIGHT SHOWERS /NO T/ LEFT IN THE SC
MTNS. HRRR AND RAP MOVE THESE SLIGHTLY TO THE WEST BEFORE KILLING
THEM OFF JUST AFTER SUNRISE. LOW CLOUDS HAVE OVERSPREAD/DEVELOPED
OVER THE ENTIRE REGION EXCEPT FOR WARREN CO. A FEW PATCHES OF
CLEAR EAST OF KIPT CAN BE IMAGINED WHEN PERUSING THE 11-3.9
MICRON IMAGERY THIS MORNING. OTHERWISE...IT IS CLOUDY. THESE
CLOUDS COULD BE TOUGH TO MIX OUT - AT LEAST IN A RAPID FASHION -
SINCE THEY ARE GENERALLY ABOVE 1KFT. THUS...WILL HANG ONTO SOME OF
THESE CLOUDS INTO THE MID TO LATE MORNING. THE EAST WILL BE
BREAKING OUT INTO THE SUN AND THE MIXING IN THE WEST COULD ALLOW A
SHOWER OR TWO TO DEVELOP IN THE AFTN. HOWEVER...MOST OF THESE WILL
REMAIN WEST OF THE CWA. ONLY THE NW IS WORTHY OF A CHC POP FOR
LATE THIS AFTN/THIS EVENING AS A LAKE BREEZE MAY KICK OFF A FEW
SHRA. THE CLOUDS WILL MAKE IT MORE DIFFICULT TO GET TO THE LOFTY
MAXES WE HAVE EXPERIENCED RECENTLY - INCLUDING TIES OF THE RECORD
HIGHS AT HARRISBURG...ALTOONA AND BRADFORD YESTERDAY. WILL GO FOR
MAXES BASED ON AN EQUAL BLEND OF MOS GUIDANCE MINUS ONE OR TWO
DEGS. THIS WILL RESULT IN ONLY A 10 DEGREE DIURNAL SWING AT MANY
PLACES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
THE UPPER LOW OVER THE UPPER GREAT LAKES WILL SLOLY FILL AND LOSE
CHARACTER. THE SFC HIGH WILL STILL NOSE INTO THE STATE...BUT THE
CENTER OF IT WILL SLIDE SOUTH INTO THE WESTERN ATLANTIC BY
MONDAY. ANY SHOWERS THIS EVENING WILL LIKELY BE IN THE NW...BUT
THE EXPECTED CELL MOTION SHOULD KEEP THEM EITHER OUT OF THE STATE
TO THE NORTH OR MAKE THE FEW THAT DO POP UP GO SLOWLY TO THE NORTH
AND OUT OF THE AREA EARLY THIS EVENING. THE LOW CLOUDS WILL
PROBABLY TRY TO REDEVELOP IN THE ERN MTNS. OTHER AREAS MAY SEE
THEM TRY TO FORM...BUT WILL KEEP IT GENERALLY P/C OVERNIGHT WITH
THE CLEARING PERHAPS ALLOWING FOR SOME MORNING FOG ON SUNDAY.
SUNDAY LOOKS TO BE DRIER AND SUNNIER...AND POPS ALMOST NON-
EXISTENT. TEMPS WILL GET A FEW DEGS F WARMER VS SATURDAY. ONCE
AGAIN...IT WILL BE THE FAR NW WHICH COULD SEE A POP UP SHOWER -
PERHAPS AGAIN BEING GENERATED ALONG A LAKE BREEZE BOUNDARY.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
THE HIGH PRESSURE WILL KEEP IT WARM AND MAINLY DRY INTO MONDAY.
A WEAK COLD FRONT WILL SLIDE SLOWLY TO THE ESE FROM THE GREAT
LAKES/MIDWEST STATES. THIS FEATURE COULD BRING SOME ISOLATED
SHRA/TSRA TO OUR NW ZONES BEGINNING TUESDAY AFTERNOON AND EVENING.
A SLOWLY AMPLIFYING BROAD TROUGH FROM THE NRN PLAINS THROUGH THE
NE U.S. WEDNESDAY AFTERNOON INTO NEXT WEEKEND WILL PUSH A
SECOND...STRONGER CFRONT EAST ACROSS THE COMMONWEALTH WEDNESDAY
NIGHT AND THURSDAY.
THIS PATTERN TRANSITION WILL BRING A FEW OPPORTUNITIES FOR
SHOWERS AND THUNDERSTORMS...ALBEIT MAINLY OF THE SCATTERED
AFTERNOON AND EVENING VARIETY.
12Z GEFS AND 12Z EC ARE IN GOOD AGREEMENT ON THE LOCATION OF THIS
TROUGH AXIS /FROM LAKE SUPERIOR TO THE MID MISS VALLEY AT 00Z
SAT/...THOUGH AS ONE WOULD EXPECT...THE ENSEMBLE MEAN DAMPENS OUT
THE AMPLITUDE OF THE TROUGH COMPARED TO THE EC.
DETAILS IN THE TIMING OF ANY SPECIFIC SHORTWAVES ROTATING THROUGH
THIS AMPLIFYING TROUGH ARE SIMPLY TOO MUDDY AT THIS TIME RANGE.
ONE THING MORE CERTAIN IN THIS MEDIUM RANGE FORECAST IS THE COOLING
TEMPS FOR THE LATTER HALF OF THE WEEK AND NEXT WEEKEND...WHEN BOTH
MAX AND MIN TEMPS COULD BE UP TO SEVERAL DEG F BELOW NORMAL
/ESPECIALLY OVER THE NRN AND WESTERN MTNS OF THE STATE...WHERE MORE
CLOUDS AND COOLER TEMPS ALOFT WILL BE FOUND/.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
ISOLD SHRA CONTINUE TO FIRE EARLY THIS AM ALONG DYING COLD FRONT
OVER SOUTH CENTRAL PA. LATEST HRRR SUGGESTS A BRIEF SHOWER WILL
REMAIN POSSIBLE THRU ARND 12Z FROM KUNV SOUTHWARD THRU KAOO AND
KJST. HOWEVER...THE MAIN CONCERN EARLY THIS MORNING WILL BE
DEVELOPING LOW CIGS...RESULTING FROM MOIST SERLY FLOW ASCENDING
THE MTNS OF CENTRAL PA. BLEND OF LATEST HRRR/LAMP SUGGEST IFR CIGS
ARE LIKELY AFTER 09Z AT KBFD/KJST AND POSSIBLE AT KAOO/KUNV. LOWER
ELEVATIONS FURTHER EAST SHOULD FARE BETTER WITH MVFR CIGS
EXPECTED. WILL HAVE TO WATCH FOR POSSIBILITY OF FOG DEVELOPMENT AT
KLNS ARND DAWN. SOME OF THE LATEST MDL DATA SUGGESTS SKIES WILL
CLEAR ACROSS THAT PART OF THE STATE ARND 10Z...ALLOWING FOR
DEVELOPMENT OF RADIATION FOG BTWN 10Z-13Z.
DIURNAL HEATING/MIXING WILL CAUSE CIGS TO RISE BY LATE AM. MDL
SOUNDINGS INDICATE MVFR CIGS MAY LINGER ACROSS THE CENTRAL MTNS
UNTIL ARND NOON. HOWEVER...BY AFTN THERE IS A HIGH DEGREE OF
CONFIDENCE IN WIDESPREAD VFR CONDS AND LIGHT WIND.
MOSTLY CLEAR SKIES AND A LIGHT WIND WILL LIKELY RESULT IN PATCHY
VALLEY FOG AGAIN EARLY SUNDAY MORNING.
OUTLOOK...
SUN-TUE...PATCHY FOG IN THE MORNING...OTHERWISE VFR.
WED...COLD FROPA WITH SCT SHRA/TSRA.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...LAMBERT
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
217 AM EDT SAT SEP 5 2015
.SYNOPSIS...
HIGH PRESSURE WILL ENSURE FAIR AND MAINLY DRY WEATHER FOR LABOR
DAY WEEKEND WITH ABOVE NORMAL WARMTH AND JUST THE CHANCE OF AN
AFTERNOON OR EVENING POP-UP SHOWER OR THUNDERSTORM.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS THE SURFACE AND UPPER LEVEL HIGH SLIDES SOUTH ALONG THE NEW
ENGLAND COAST...IT IS FORCING A DEEP EASTERLY FLOW INTO THE AREA.
WEAK LOCAL FORCING...RESIDUAL INSTABILITY AND A GENERAL UPSLOPE
COMPONENT TO THE LOW LEVEL FLOW ARE ALL COMBINING TO KEEP SOME
SCATTERED SHOWERS AND THUNDERSTORMS FLOATING AROUND IN A RATHER
DISORGANIZED FASHION AS OF LATE EVENING.
THE HRRR KEEPS TRYING TO ORGANIZE A SMALL MCS WHICH IT TRACKS
THROUGH THE SOUTH CENTRAL MOUNTAINS BETWEEN ABOUT 5 AND 11Z. THIS
SEEMS OVERDONE AND WILL MORE LIKELY BE ISOLATED LEFT OVER
ACTIVITY... GIVEN THE NEGATIVE TREND IN OBSERVED CAPE AND THE
NORMAL DIURNAL DIE OFF TIME...AND EVEN COULD BE PORTRAYING AN
INCREASE IN LOW CLOUDS/MOISTURE THAT SHOULD START ADVECTING WEST
IN THE MARITIME FLOW.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SUNDAY/...
FOR SATURDAY MODEL MID LEVEL TEMPS ARE EXPECTED TO INCREASE TO
VALUES CLOSER TO WHAT WE NORMALLY SEE ACT AS AN EFFECTIVE CAP IN
THE LOCAL AREA. BETWEEN THAT AND MORE IN THE WAY OF LOW
CLOUDINESS...WE SHOULD BE COOLER IN THE LOW LEVELS AND WARMER
ALOFT WHICH WILL EQUATE TO LESS INSTABILITY AND A SMALLER CHANCE FOR
SHOWERS. THE BEST CHANCE FOR AN ISOLATED STORM WILL BE OVER
WESTERN AREAS DURING THE LATTER HALF OF THE DAY.
HIGHS WILL BE A FEW DEGREES COOLER THAN PREVIOUS DAYS AND
DEWPOINTS WILL EVEN NUDGE DOWN A BIT AS LOWER DEWPOINTS START TO
ADVECT IN FORM THE NORTHEAST.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
A RATHER LARGE AREA OF HIGH PRESSURE AT THE SFC...AND A SLOWLY
FLATTENING UPPER RIDGE OVER THE EASTERN U.S...SHOULD MAINTAIN DRY
WEATHER SATURDAY NIGHT THROUGH MONDAY. PRECIPITABLE WATER VALUES
WILL RANGE FROM BELOW NORMAL AND ONLY AROUND ONE-HALF OF AN INCH
ACROSS FAR NERN PENN...TO SLIGHTLY ABOVE NORMAL ALONG THE SE SHORE
OF LAKE ERIE SUNDAY SATURDAY NIGHT INTO SUNDAY NIGHT. A FEW SHOWERS
OR EVEN A BRIEF TSRA COULD BRUSH OUR FAR NW ZONES DURING THIS
INITIAL 24 HOURS OF THE LONG TERM PERIOD...BUT POPS WILL BE LESS
THAN 25 PERCENT.
AN INITIAL...WEAK...COLD FRONT WILL SLIDE SLOWLY TO THE ESE FROM THE
GREAT LAKES/MIDWEST STATES. THIS FEATURE COULD BRING SOME ISOLATED
SHRA/TSRA TO OUR NW ZONES BEGINNING TUESDAY AFTERNOON AND EVENING.
A SLOWLY AMPLIFYING...BROAD TROUGH FROM THE NRN PLAINS THROUGH THE
NE U.S. WEDNESDAY AFTERNOON INTO NEXT WEEKEND WILL PUSH A
SECOND...STRONGER CFRONT EAST ACROSS THE COMMONWEALTH WEDNESDAY
NIGHT AND THURSDAY.
THIS PATTERN TRANSITION WILL BRING A FEW OPPORTUNITIES FOR
SHOWERS AND THUNDERSTORMS...ALBEIT MAINLY OF THE SCATTERED
AFTERNOON AND EVENING VARIETY.
12Z GEFS AND 12Z EC ARE IN GOOD AGREEMENT ON THE LOCATION OF THIS
TROUGH AXIS /FROM LAKE SUPERIOR TO THE MID MISS VALLEY AT 00Z
SAT/...THOUGH AS ONE WOULD EXPECT...THE ENSEMBLE MEAN DAMPENS OUT
THE AMPLITUDE OF THE TROUGH COMPARED TO THE EC.
DETAILS IN THE TIMING OF ANY SPECIFIC SHORTWAVES ROTATING THROUGH
THIS AMPLIFYING TROUGH ARE SIMPLY TOO MUDDY AT THIS TIME RANGE.
ONE THING MORE CERTAIN IN THIS MEDIUM RANGE FORECAST IS THE COOLING
TEMPS FOR THE LATTER HALF OF THE WEEK AND NEXT WEEKEND...WHEN BOTH
MAX AND MIN TEMPS COULD BE UP TO SEVERAL DEG F BELOW NORMAL
/ESPECIALLY OVER THE NRN AND WESTERN MTNS OF THE STATE...WHERE MORE
CLOUDS AND COOLER TEMPS ALOFT WILL BE FOUND/.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
ISOLD SHRA CONTINUE TO FIRE EARLY THIS AM ALONG DYING COLD FRONT
OVER SOUTH CENTRAL PA. LATEST HRRR SUGGESTS A BRIEF SHOWER WILL
REMAIN POSSIBLE THRU ARND 12Z FROM KUNV SOUTHWARD THRU KAOO AND
KJST. HOWEVER...THE MAIN CONCERN EARLY THIS MORNING WILL BE
DEVELOPING LOW CIGS...RESULTING FROM MOIST SERLY FLOW ASCENDING
THE MTNS OF CENTRAL PA. BLEND OF LATEST HRRR/LAMP SUGGEST IFR CIGS
ARE LIKELY AFTER 09Z AT KBFD/KJST AND POSSIBLE AT KAOO/KUNV. LOWER
ELEVATIONS FURTHER EAST SHOULD FARE BETTER WITH MVFR CIGS
EXPECTED. WILL HAVE TO WATCH FOR POSSIBILITY OF FOG DEVELOPMENT AT
KLNS ARND DAWN. SOME OF THE LATEST MDL DATA SUGGESTS SKIES WILL
CLEAR ACROSS THAT PART OF THE STATE ARND 10Z...ALLOWING FOR
DEVELOPMENT OF RADIATION FOG BTWN 10Z-13Z.
DIURNAL HEATING/MIXING WILL CAUSE CIGS TO RISE BY LATE AM. MDL
SOUNDINGS INDICATE MVFR CIGS MAY LINGER ACROSS THE CENTRAL MTNS
UNTIL ARND NOON. HOWEVER...BY AFTN THERE IS A HIGH DEGREE OF
CONFIDENCE IN WIDESPREAD VFR CONDS AND LIGHT WIND.
MOSTLY CLEAR SKIES AND A LIGHT WIND WILL LIKELY RESULT IN PATCHY
VALLEY FOG AGAIN EARLY SUNDAY MORNING.
OUTLOOK...
SUN-TUE...PATCHY FOG IN THE MORNING...OTHERWISE VFR.
WED...COLD FROPA WITH SCT SHRA/TSRA.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...DANGELO/GARTNER
LONG TERM...LAMBERT
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
343 PM CDT SAT SEP 5 2015
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 342 PM CDT SAT SEP 5 2015
SHORT WAVE LIFTING NORTH NORTHEAST OUT OF NORTH CENTRAL NEBRASKA
WILL TRACK THROUGH SOUTH CENTRAL SOUTH DAKOTA INTO EAST CENTRAL
MINNESOTA LATE THIS EVENING. PLENTY OF LOW LEVEL MOISTURE AND WARM
AIR ADVECTION IS STREAMING ACROSS THE REGION AHEAD OF THIS WAVE. MID
AND HIGH CLOUDS BLANKETING OUR EASTERN HALF HAVE REALLY PREVENTED
TEMPERATURES FROM HEATING MUCH SO FAR TODAY. WITH THE FILTERED
SUNSHINE AND COOLER THAN EXPECTED TEMPERATURES...STRONG CAPPING
SHOULD PREVENT ANY SEVERE WEATHER FROM DEVELOPING THIS AFTERNOON AND
EVENING. THE HRRR AND NAM ARE FAR TOO AGGRESSIVE WITH DEVELOPING
CONVECTION...WHILE THE GFS...CANADIAN AND ECMWF PAINT VERY LITTLE
PRECIPITATION THROUGH MUCH OF THE OVERNIGHT. DID SOMETHING OF A
BLEND OF ALL OF THESE MODELS TO ACCOUNT FOR SOME ONGOING SCATTERED
SHOWER ACTIVITY WHICH THE LATER MODELS ARE NOT HANDLING WELL.
OTHERWISE...EXPECT THE SOME SCATTERED HIGH BASED SHOWERS LIFTING
INTO SOUTH CENTRAL SD TO CONTINUE LIFTING NORTH NORTHEAST ACROSS OUR
WESTERN HALF...WITH THE LINE SLOWLY SHIFTING EASTWARD THROUGH THE
OVERNIGHT HOURS. NOT SEEING MUCH LIGHTNING WITH THIS ACTIVITY...BUT
WE COULD SEE A FEW EMBEDDED CELLS BECOME MORE ORGANIZED WITH SOME
LIGHTNING STRIKES SO WILL LEAVE THE THUNDER MENTION IN PLACE. WHILE
THIS ACTIVITY MAY WAN SOME IN THE EARLY MORNING HOURS...THE LOW
LEVEL JET ONCE AGAIN KICKS IN LATE TONIGHT AND WILL LIKELY REIGNITE
SHOWERS AND STORMS. BY MID MORNING THE LOW LEVEL JET
WEAKENS...HOWEVER A COLD FRONT IS EXPECTED TO PUSH INTO THE WESTERN
FORECAST AREA AND GRADUALLY TRACK SOUTHEAST THROUGH THE FORECAST
AREA INTO THE AFTERNOON. BY MID AFTERNOON...THUNDERSTORM ACTIVITY
MAY INCREASE AGAIN IN THE AFTERNOON AHEAD OF THE FRONT IN OUR FAR
SOUTHEASTERN COUNTIES. THE BIG QUESTION WILL BE HOW WELL THIS AREA
WILL BE ABLE TO DESTABILIZE IN THE AFTERNOON. WITH CLOUDS AND
PRECIPITATION EARLY IN THE DAY...TEMPERATURES MAY NOT HEAT AS WELL
AS MODELS INDICATE. MEAGER SHEAR PROFILES BUT CONDITIONALLY GOOD
CAPE VALUES MAY ALLOW A FEW STRONG TO SEVERE STORMS TO FORM MID TO
AFTERNOON. WITH CLOUDS AROUND FOR MUCH OF THE DAY...HIGHS WILL BE
TRICKY. EXPECT MOST PLACES TO REACH THE LOW TO MID 80S.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 342 PM CDT SAT SEP 5 2015
CONVOLUTED FORECAST IN THE MEDIUM RANGE AS FORECAST IS VERY
DEPENDENT ON FRONTAL PLACEMENT. CURRENTLY...MODELS ARE OFFERING A
VARIETY OF SOLUTIONS IN TERMS OF FRONTAL PLACEMENT...MAKING FOR A
DIFFICULT FORECAST IN THE NEAR TERM. MODELS ARE DIFFERING WITHIN
THE TYPICAL BIAS REGIME...WITH THE GFS OFFERING A MORE PROGRESSIVE
SOLUTION THAN THE NAM AND REALITY LIKELY LYING IN THE MIDDLE. AHEAD
OF THE BOUNDARY...ATMOSPHERE IS UNSTABLE WITH 1000-1500 CAPE WITH
LIMITED CIN. SPC HAS EXPANDED SEVERE THREAT FOR DAY 2...BUT AM NOT
OVERLY EXCITED BY SEVERE THREAT WITH SHEAR VALUES FAIRLY LIMITED.
AM ONCE AGAIN CONCERNED ABOUT HEAVY RAIN POTENTIAL AND TRAINING OF
STORMS AHEAD OF THE FRONT...WITH PRECONVECTIVE PWAT VALUES NEAR
1.8"...NEAR RECORD LEVELS FOR THIS TIME OF YEAR.
THE BOUNDARY IS EXPECTED TO STALL OUT. CONSENSUS SUGGESTS THE
BOUNDARY WILL STALL JUST SOUTH OF THE FORECAST AREA...AND WITH THE
BOUNDARY HANGING AROUND..THERE IS LINGERING CHANCE OF PRECIPITATION
NEAR THE BOUNDARY. WITH FAIRLY STRONG SHORT WAVE TRACKING JUST SOUTH
OF THE FORECAST AREA ON MONDAY AFTERNOON INTO MONDAY NIGHT...HAVE
KEPT POPS IN THE SOUTH...BUT HAVE CUT POPS BACK ACROSS THE NORTH.
MODELS SUGGEST A STRONG COLD FRONT MOVING THROUGH THE AREA ON
WEDNESDAY. UPPER WAVE CONCENTRATED TO THE NORTH EAST...BUT A CHANCE
OF SHOWERS ACROSS THE AREA WITH VERY LIMITED INSTABILITY AS THE
FRONT MOVES THROUGH. HAVE CUT HIGHS BACK SOME ON WEDNESDAY WITH
CLOUDS AND FLOW BECOMING NORTHEAST.
COOL AND DRY CONDITIONS EXPECTED FOR THE REGION THROUGH THE
REMAINDER OF THE WEEK...WITH HIGHS 5-10 BELOW AVERAGE AND LOWS
AROUND 5 DEGREES BELOW NORMAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1249 PM CDT SAT SEP 5 2015
HIGH BASED CLOUDS AND CONVECTION WILL BE THE MAIN CONCERNS THROUGH
THE TAF PERIOD. EXPECT SOME SCATTERED SHRA TO TRACK FROM SOUTH
CENTRAL SD INTO NORTHEAST SD THIS AFTERNOON...WITH THIS BAND
NUDGING SLOWLY EASTWARD THROUGH THE OVERNIGHT HOURS.
ADDITIONALLY...A FEW MORE ORGANIZED TSRA MAY DEVELOP IN NORTH
CENTRAL NEBRASKA LATE AFTERNOON AND EVENING AND TRACK INTO OUR
WESTERN COUNTIES...ALLOWING FOR SOME MVFR VISIBILITY UNDER THE
STRONGER TSRA. FRONTAL BOUNDARY DROPPING INTO OUR WEST LATE
TONIGHT WILL APPROACH THE I29 CORRIDOR AROUND 18Z. EXPECT BREEZY
WINDS AHEAD OF AND BEHIND THE FRONT. LATE TONIGHT THERE MAY BE A
CONCERN WITH LOW LEVEL WINDS CREATING SOME WIND SHEAR CONCERNS AT
KSUX AND KHON THROUGH MID MORNING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...
LONG TERM...
AVIATION...
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1243 PM CDT SAT SEP 5 2015
.DISCUSSION...SEE 18Z AVIATION DISCUSSION.
&&
.AVIATION...WILL MAINTAIN THE VCSH/TEMPO SHRA AT KVCT BASED ON
RADAR AND HRRR DATA...BUT ONLY UNTIL 21Z/20Z...RESPECTIVELY AS
EXPECT ACTIVITY TO MOVE NORTH AFTER 21Z. NO CONVECTION MENTIONED
ELSEWHERE IN THE TERMINALS. GUSTY SSE WINDS THIS AFTERNOON LOSE
THEIR GUSTS ABOUT AN HOUR AFTER SUNSET (KLRD ABOUT 3 HOURS
AFTER)...THEN BECOME RELATIVELY LIGHT OVERNIGHT. COULD HAVE SOME
LIGHT FOG AGAIN AT KALI AND KVCT...BUT ONLY PUT IT IN FOR KVCT
SINCE BOUNDARY LAYER WINDS MAY BE A BIT TOO HIGH IN KALI AND HAVE
MVFR CIGS THERE. OTHERWISE...MVFR CIGS (AT LEAST TEMPO) AT KCRP
AND KALI BY 11Z...THEN END ABOUT 14Z. WINDS SOUTH AFTER SUNRISE
AROUND 11 KNOTS (MORE AT KCRP AND KLRD...LESS OTHER TWO SITE) FOR
THE REMAINDER OF THE TERMINAL FORECAST. NO CONVECTION EXPECTED AND
NONE MENTIONED IN THE TERMINALS FOR SUNDAY.
&&
.PREV DISCUSSION... /ISSUED 1015 AM CDT SAT SEP 5 2015/
DISCUSSION...A FEW CHANGES TO THE PREVIOUS FORECAST...MAINLY DEW
POINTS WHICH WERE TOO LOW IN A FEW LOCATIONS. STILL...GIVEN THE
UPDATED VALUES...HEAT INDICES BETWEEN 105 AND 109 ARE BEING
FORECAST (SPS HAS BEEN SENT OUT). WILL MONITOR AS THIS IS THE
LABOR DAY WEEKEND SO WILL HAVE TO KEEP A KEENER EYE ON THIS.
BOUNDARY LAYER WINDS A BIT HIGHER TODAY AND THE RIDGE A BIT
STRONGER...FEEL CONVECTION THIS AFTERNOON WILL BE MORE LIMITED AND
MAINLY OVER THE NORTHERN AREAS BEFORE ENDING BY LATE AFTERNOON.
THIS KIND OF FOLLOWS WHAT THE HRRR AND NSSL MODELS ARE INDICATING
SO ADJUSTED AFTERNOON POPS ACCORDINGLY. HIGH TEMPERATURE FORECAST
LOOKS REASONABLE. ADJUSTED CLOUD COVER TOO. MINOR ADJUSTMENTS TO
SECOND PERIOD TO ACCOUNT FOR FIRST PERIOD CHANGES. NO OTHER
UPDATES FOR OTHER PERIODS AT THIS TIME.
PREV DISCUSSION... /ISSUED 638 AM CDT SAT SEP 5 2015/
DISCUSSION...UPDATED FOR 12Z AVIATION.
AVIATION...POCKETS OF PATCHY FOG AND LOW CLOUDS HAVE DEVELOPED
THIS MORNING AND COULD IMPACT ALI/VCT/LRD FOR THE NEXT COUPLE OF
HOURS. ALSO...ISOLATED SHOWERS HAVE DEVELOPED NORTH OF PORT
ARANSAS INTO THE NORTHERN COASTAL BEND AND WILL CONTINUE TO MOVE
INLAND THIS MORNING. ONLY HAVE INCLUDED VCSH REMARKS FOR THE VCT
TERMINAL AS CONFIDENCE IS LOW TO MENTION PRECIP REMARKS AT THE
OTHER TERMINALS. WINDS WILL BE PREDOMINANTLY OUT OF THE SSE AND SE
WITH GUSTS AOA 20 KNOTS IN THE AFTERNOON. ANOTHER ROUND OF LOW
CLOUDS MAY DEVELOP LATE TONIGHT AND HAVE MENTIONED MVFR CIGS AT
ALI/VCT/CRP.
PREV DISCUSSION... /ISSUED 345 AM CDT SAT SEP 5 2015/
SHORT TERM (TODAY THROUGH SUNDAY)...UPPER LEVEL RIDGE WILL
BUILD OVER SOUTH TEXAS TODAY INTO SUNDAY. MOISTURE WILL BE A
LITTLE LESS TODAY AS MODELS PROG PW VALUES BETWEEN 1.7 TO 1.9
INCHES. ISOLATED CONVECTION OVER THE MARINE WATERS MAY APPROACH
THE COAST LATER THIS MORNING. THEN...DAYTIME HEATING COMBINED WITH
THE SEA BREEZE MAY BE ENOUGH TO GENERATE ISOLATED TO POSSIBLY
SCATTERED SHOWERS AND A FEW STORMS. LAST FEW RUNS OF THE HRRR AT
LEAST SUPPORT THIS TO SOME EXTENT...AND HAVE KEPT 20 POPS ACROSS
THE EAST WITH SOME 30 POPS ACROSS THE VICTORIA CROSSROADS.
CONDITIONS SHOULD BE A LITTLE WARMER TODAY COMPARED TO YESTERDAY
AS HIGHS CLIMB INTO THE LOWER 100S OUT WEST...TO MID/LOWER 90S
ACROSS THE EAST AND NORTHEAST. MOISTURE DECREASES A LITTLE MORE ON
SUNDAY AND GUIDANCE IS NOT TOO OPTIMISTIC ABOUT RAIN CHANCES. WILL
LEAVE RAIN CHANCES OUT OF THE FORECAST FOR NOW. ABOVE NORMAL
TEMPERATURES WILL CONTINUE ON SUNDAY.
LONG TERM (SUNDAY NIGHT THROUGH FRIDAY)...CHANGES IN THE UPPER
PATTERN TAKE PLACE BY SUNDAY NIGHT WITH H5 RIDGE FLATTENS AND SLIDES
WEST AS A TROUGH SWINGS EAST ACROSS THE HIGH PLAINS AND A WEAK CUT
OFF LOW DRIFTS WEST ALONG ACROSS THE GULF STATES INTO THE WESTERN
GULF. MODELS DISAGREE ON THE AMOUNT OF MOISTURE AVAILABLE...BUT
OVERALL...A RELATIVE INCREASE IN MOISTURE MOVES INTO THE WESTERN
GULF AS WELL AS THE EASTERN HALF OF THE CWA...AND IS DRAWN NORTH
INTO THE CENTRAL PLAINS. WITH WEAKNESS ALOFT AND SLIGHTLY COOL H85-
H7 TEMPS...DAILY CONVECTION IS EXPECTED THROUGH THE WEEK IN THE FORM
OF SHOWERS IN THE MORNING ACROSS THE GULF...MOVING INLAND WITH
HEATING. THE GFS AND EURO BOTH HINT AT A SURFACE FRONT TO MOVE
THROUGH THE CENTRAL PLAINS AND PUSH SOUTH INTO TEXAS. DISAGREEMENTS
DEVELOP BETWEEN THE LONG TERM MODELS ON THE DEVELOPMENT AND TIMING
OF THE FRONT FROM THURSDAY AND ONWARD. THIS SAID...MAINLY KEPT
SLIGHT CHANCE POPS FROM MONDAY THROUGH WEDNESDAY FOR ISOLATED
ACTIVITY ACROSS THE NORTHERN COASTAL BEND AND COASTAL PLAINS...WITH
20-30 POPS INTRODUCED BY FRIDAY DUE TO PROXIMITY OF THE BOUNDARY.
TEMPERATURES FOR THE MOST PART WILL BE SLIGHTLY ABOVE NORMAL THROUGH
MUCH OF THE WEEK...WITH COOLER TEMPS TOWARD THE LATER OF THE WORK
WEEK MAINLY DUE TO THE INCREASED CLOUD COVERAGE AND RAIN CHANCES.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 94 79 94 77 94 / 20 10 10 10 20
VICTORIA 94 76 96 75 95 / 30 10 10 10 20
LAREDO 102 79 102 77 102 / 10 10 0 0 10
ALICE 97 76 98 75 98 / 20 10 10 10 10
ROCKPORT 91 80 91 79 90 / 30 10 10 10 20
COTULLA 101 77 101 75 102 / 10 10 0 0 10
KINGSVILLE 96 78 97 76 97 / 20 10 10 10 10
NAVY CORPUS 90 80 90 80 90 / 20 10 10 10 20
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
GW/86...AVIATION
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1015 AM CDT SAT SEP 5 2015
.DISCUSSION...A FEW CHANGES TO THE PREVIOUS FORECAST...MAINLY DEW
POINTS WHICH WERE TOO LOW IN A FEW LOCATIONS. STILL...GIVEN THE
UPDATED VALUES...HEAT INDICES BETWEEN 105 AND 109 ARE BEING
FORECAST (SPS HAS BEEN SENT OUT). WILL MONITOR AS THIS IS THE
LABOR DAY WEEKEND SO WILL HAVE TO KEEP A KEENER EYE ON THIS.
BOUNDARY LAYER WINDS A BIT HIGHER TODAY AND THE RIDGE A BIT
STRONGER...FEEL CONVECTION THIS AFTERNOON WILL BE MORE LIMITED AND
MAINLY OVER THE NORTHERN AREAS BEFORE ENDING BY LATE AFTERNOON.
THIS KIND OF FOLLOWS WHAT THE HRRR AND NSSL MODELS ARE INDICATING
SO ADJUSTED AFTERNOON POPS ACCORDINGLY. HIGH TEMPERATURE FORECAST
LOOKS REASONABLE. ADJUSTED CLOUD COVER TOO. MINOR ADJUSTMENTS TO
SECOND PERIOD TO ACCOUNT FOR FIRST PERIOD CHANGES. NO OTHER
UPDATES FOR OTHER PERIODS AT THIS TIME.
&&
.PREV DISCUSSION... /ISSUED 638 AM CDT SAT SEP 5 2015/
DISCUSSION...UPDATED FOR 12Z AVIATION.
AVIATION...POCKETS OF PATCHY FOG AND LOW CLOUDS HAVE DEVELOPED
THIS MORNING AND COULD IMPACT ALI/VCT/LRD FOR THE NEXT COUPLE OF
HOURS. ALSO...ISOLATED SHOWERS HAVE DEVELOPED NORTH OF PORT
ARANSAS INTO THE NORTHERN COASTAL BEND AND WILL CONTINUE TO MOVE
INLAND THIS MORNING. ONLY HAVE INCLUDED VCSH REMARKS FOR THE VCT
TERMINAL AS CONFIDENCE IS LOW TO MENTION PRECIP REMARKS AT THE
OTHER TERMINALS. WINDS WILL BE PREDOMINANTLY OUT OF THE SSE AND SE
WITH GUSTS AOA 20 KNOTS IN THE AFTERNOON. ANOTHER ROUND OF LOW
CLOUDS MAY DEVELOP LATE TONIGHT AND HAVE MENTIONED MVFR CIGS AT
ALI/VCT/CRP.
PREV DISCUSSION... /ISSUED 345 AM CDT SAT SEP 5 2015/
SHORT TERM (TODAY THROUGH SUNDAY)...UPPER LEVEL RIDGE WILL
BUILD OVER SOUTH TEXAS TODAY INTO SUNDAY. MOISTURE WILL BE A
LITTLE LESS TODAY AS MODELS PROG PW VALUES BETWEEN 1.7 TO 1.9
INCHES. ISOLATED CONVECTION OVER THE MARINE WATERS MAY APPROACH
THE COAST LATER THIS MORNING. THEN...DAYTIME HEATING COMBINED WITH
THE SEA BREEZE MAY BE ENOUGH TO GENERATE ISOLATED TO POSSIBLY
SCATTERED SHOWERS AND A FEW STORMS. LAST FEW RUNS OF THE HRRR AT
LEAST SUPPORT THIS TO SOME EXTENT...AND HAVE KEPT 20 POPS ACROSS
THE EAST WITH SOME 30 POPS ACROSS THE VICTORIA CROSSROADS.
CONDITIONS SHOULD BE A LITTLE WARMER TODAY COMPARED TO YESTERDAY
AS HIGHS CLIMB INTO THE LOWER 100S OUT WEST...TO MID/LOWER 90S
ACROSS THE EAST AND NORTHEAST. MOISTURE DECREASES A LITTLE MORE ON
SUNDAY AND GUIDANCE IS NOT TOO OPTIMISTIC ABOUT RAIN CHANCES. WILL
LEAVE RAIN CHANCES OUT OF THE FORECAST FOR NOW. ABOVE NORMAL
TEMPERATURES WILL CONTINUE ON SUNDAY.
LONG TERM (SUNDAY NIGHT THROUGH FRIDAY)...CHANGES IN THE UPPER
PATTERN TAKE PLACE BY SUNDAY NIGHT WITH H5 RIDGE FLATTENS AND SLIDES
WEST AS A TROUGH SWINGS EAST ACROSS THE HIGH PLAINS AND A WEAK CUT
OFF LOW DRIFTS WEST ALONG ACROSS THE GULF STATES INTO THE WESTERN
GULF. MODELS DISAGREE ON THE AMOUNT OF MOISTURE AVAILABLE...BUT
OVERALL...A RELATIVE INCREASE IN MOISTURE MOVES INTO THE WESTERN
GULF AS WELL AS THE EASTERN HALF OF THE CWA...AND IS DRAWN NORTH
INTO THE CENTRAL PLAINS. WITH WEAKNESS ALOFT AND SLIGHTLY COOL H85-
H7 TEMPS...DAILY CONVECTION IS EXPECTED THROUGH THE WEEK IN THE FORM
OF SHOWERS IN THE MORNING ACROSS THE GULF...MOVING INLAND WITH
HEATING. THE GFS AND EURO BOTH HINT AT A SURFACE FRONT TO MOVE
THROUGH THE CENTRAL PLAINS AND PUSH SOUTH INTO TEXAS. DISAGREEMENTS
DEVELOP BETWEEN THE LONG TERM MODELS ON THE DEVELOPMENT AND TIMING
OF THE FRONT FROM THURSDAY AND ONWARD. THIS SAID...MAINLY KEPT
SLIGHT CHANCE POPS FROM MONDAY THROUGH WEDNESDAY FOR ISOLATED
ACTIVITY ACROSS THE NORTHERN COASTAL BEND AND COASTAL PLAINS...WITH
20-30 POPS INTRODUCED BY FRIDAY DUE TO PROXIMITY OF THE BOUNDARY.
TEMPERATURES FOR THE MOST PART WILL BE SLIGHTLY ABOVE NORMAL THROUGH
MUCH OF THE WEEK...WITH COOLER TEMPS TOWARD THE LATER OF THE WORK
WEEK MAINLY DUE TO THE INCREASED CLOUD COVERAGE AND RAIN CHANCES.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 94 79 94 77 94 / 20 10 10 10 20
VICTORIA 94 76 96 75 95 / 30 10 10 10 20
LAREDO 102 79 102 77 102 / 10 10 0 0 10
ALICE 97 76 98 75 98 / 20 10 10 10 10
ROCKPORT 91 80 91 79 90 / 30 10 10 10 20
COTULLA 101 77 101 75 102 / 10 10 0 0 10
KINGSVILLE 96 78 97 76 97 / 20 10 10 10 10
NAVY CORPUS 90 80 90 80 90 / 20 10 10 10 20
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
GW/86...SHORT TERM
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
638 AM CDT SAT SEP 5 2015
.DISCUSSION...UPDATED FOR 12Z AVIATION.
&&
.AVIATION...POCKETS OF PATCHY FOG AND LOW CLOUDS HAVE DEVELOPED
THIS MORNING AND COULD IMPACT ALI/VCT/LRD FOR THE NEXT COUPLE OF
HOURS. ALSO...ISOLATED SHOWERS HAVE DEVELOPED NORTH OF PORT
ARANSAS INTO THE NORTHERN COASTAL BEND AND WILL CONTINUE TO MOVE
INLAND THIS MORNING. ONLY HAVE INCLUDED VCSH REMARKS FOR THE VCT
TERMINAL AS CONFIDENCE IS LOW TO MENTION PRECIP REMARKS AT THE
OTHER TERMINALS. WINDS WILL BE PREDOMINANTLY OUT OF THE SSE AND SE
WITH GUSTS AOA 20 KNOTS IN THE AFTERNOON. ANOTHER ROUND OF LOW
CLOUDS MAY DEVELOP LATE TONIGHT AND HAVE MENTIONED MVFR CIGS AT
ALI/VCT/CRP.
&&
.PREV DISCUSSION... /ISSUED 345 AM CDT SAT SEP 5 2015/
SHORT TERM (TODAY THROUGH SUNDAY)...UPPER LEVEL RIDGE WILL
BUILD OVER SOUTH TEXAS TODAY INTO SUNDAY. MOISTURE WILL BE A
LITTLE LESS TODAY AS MODELS PROG PW VALUES BETWEEN 1.7 TO 1.9
INCHES. ISOLATED CONVECTION OVER THE MARINE WATERS MAY APPROACH
THE COAST LATER THIS MORNING. THEN...DAYTIME HEATING COMBINED WITH
THE SEA BREEZE MAY BE ENOUGH TO GENERATE ISOLATED TO POSSIBLY
SCATTERED SHOWERS AND A FEW STORMS. LAST FEW RUNS OF THE HRRR AT
LEAST SUPPORT THIS TO SOME EXTENT...AND HAVE KEPT 20 POPS ACROSS
THE EAST WITH SOME 30 POPS ACROSS THE VICTORIA CROSSROADS.
CONDITIONS SHOULD BE A LITTLE WARMER TODAY COMPARED TO YESTERDAY
AS HIGHS CLIMB INTO THE LOWER 100S OUT WEST...TO MID/LOWER 90S
ACROSS THE EAST AND NORTHEAST. MOISTURE DECREASES A LITTLE MORE ON
SUNDAY AND GUIDANCE IS NOT TOO OPTIMISTIC ABOUT RAIN CHANCES. WILL
LEAVE RAIN CHANCES OUT OF THE FORECAST FOR NOW. ABOVE NORMAL
TEMPERATURES WILL CONTINUE ON SUNDAY.
LONG TERM (SUNDAY NIGHT THROUGH FRIDAY)...CHANGES IN THE UPPER
PATTERN TAKE PLACE BY SUNDAY NIGHT WITH H5 RIDGE FLATTENS AND SLIDES
WEST AS A TROUGH SWINGS EAST ACROSS THE HIGH PLAINS AND A WEAK CUT
OFF LOW DRIFTS WEST ALONG ACROSS THE GULF STATES INTO THE WESTERN
GULF. MODELS DISAGREE ON THE AMOUNT OF MOISTURE AVAILABLE...BUT
OVERALL...A RELATIVE INCREASE IN MOISTURE MOVES INTO THE WESTERN
GULF AS WELL AS THE EASTERN HALF OF THE CWA...AND IS DRAWN NORTH
INTO THE CENTRAL PLAINS. WITH WEAKNESS ALOFT AND SLIGHTLY COOL H85-
H7 TEMPS...DAILY CONVECTION IS EXPECTED THROUGH THE WEEK IN THE FORM
OF SHOWERS IN THE MORNING ACROSS THE GULF...MOVING INLAND WITH
HEATING. THE GFS AND EURO BOTH HINT AT A SURFACE FRONT TO MOVE
THROUGH THE CENTRAL PLAINS AND PUSH SOUTH INTO TEXAS. DISAGREEMENTS
DEVELOP BETWEEN THE LONG TERM MODELS ON THE DEVELOPMENT AND TIMING
OF THE FRONT FROM THURSDAY AND ONWARD. THIS SAID...MAINLY KEPT
SLIGHT CHANCE POPS FROM MONDAY THROUGH WEDNESDAY FOR ISOLATED
ACTIVITY ACROSS THE NORTHERN COASTAL BEND AND COASTAL PLAINS...WITH
20-30 POPS INTRODUCED BY FRIDAY DUE TO PROXIMITY OF THE BOUNDARY.
TEMPERATURES FOR THE MOST PART WILL BE SLIGHTLY ABOVE NORMAL THROUGH
MUCH OF THE WEEK...WITH COOLER TEMPS TOWARD THE LATER OF THE WORK
WEEK MAINLY DUE TO THE INCREASED CLOUD COVERAGE AND RAIN CHANCES.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 94 79 94 77 94 / 20 10 10 10 20
VICTORIA 94 76 96 75 95 / 30 10 10 10 20
LAREDO 102 79 102 77 102 / 10 10 0 0 10
ALICE 97 76 98 75 98 / 20 10 10 10 10
ROCKPORT 91 80 91 79 90 / 30 10 10 10 20
COTULLA 101 77 101 75 102 / 10 10 0 0 10
KINGSVILLE 96 78 97 76 97 / 20 10 10 10 10
NAVY CORPUS 90 80 90 80 90 / 20 10 10 10 20
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
TB/78...AVIATION
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
345 AM CDT SAT SEP 5 2015
.SHORT TERM (TODAY THROUGH SUNDAY)...UPPER LEVEL RIDGE WILL
BUILD OVER SOUTH TEXAS TODAY INTO SUNDAY. MOISTURE WILL BE A
LITTLE LESS TODAY AS MODELS PROG PW VALUES BETWEEN 1.7 TO 1.9
INCHES. ISOLATED CONVECTION OVER THE MARINE WATERS MAY APPROACH
THE COAST LATER THIS MORNING. THEN...DAYTIME HEATING COMBINED WITH
THE SEA BREEZE MAY BE ENOUGH TO GENERATE ISOLATED TO POSSIBLY
SCATTERED SHOWERS AND A FEW STORMS. LAST FEW RUNS OF THE HRRR AT
LEAST SUPPORT THIS TO SOME EXTENT...AND HAVE KEPT 20 POPS ACROSS
THE EAST WITH SOME 30 POPS ACROSS THE VICTORIA CROSSROADS.
CONDITIONS SHOULD BE A LITTLE WARMER TODAY COMPARED TO YESTERDAY
AS HIGHS CLIMB INTO THE LOWER 100S OUT WEST...TO MID/LOWER 90S
ACROSS THE EAST AND NORTHEAST. MOISTURE DECREASES A LITTLE MORE ON
SUNDAY AND GUIDANCE IS NOT TOO OPTIMISTIC ABOUT RAIN CHANCES. WILL
LEAVE RAIN CHANCES OUT OF THE FORECAST FOR NOW. ABOVE NORMAL
TEMPERATURES WILL CONTINUE ON SUNDAY.
&&
.LONG TERM (SUNDAY NIGHT THROUGH FRIDAY)...CHANGES IN THE UPPER
PATTERN TAKE PLACE BY SUNDAY NIGHT WITH H5 RIDGE FLATTENS AND SLIDES
WEST AS A TROUGH SWINGS EAST ACROSS THE HIGH PLAINS AND A WEAK CUT
OFF LOW DRIFTS WEST ALONG ACROSS THE GULF STATES INTO THE WESTERN
GULF. MODELS DISAGREE ON THE AMOUNT OF MOISTURE AVAILABLE...BUT
OVERALL...A RELATIVE INCREASE IN MOISTURE MOVES INTO THE WESTERN
GULF AS WELL AS THE EASTERN HALF OF THE CWA...AND IS DRAWN NORTH
INTO THE CENTRAL PLAINS. WITH WEAKNESS ALOFT AND SLIGHTLY COOL H85-
H7 TEMPS...DAILY CONVECTION IS EXPECTED THROUGH THE WEEK IN THE FORM
OF SHOWERS IN THE MORNING ACROSS THE GULF...MOVING INLAND WITH
HEATING. THE GFS AND EURO BOTH HINT AT A SURFACE FRONT TO MOVE
THROUGH THE CENTRAL PLAINS AND PUSH SOUTH INTO TEXAS. DISAGREEMENTS
DEVELOP BETWEEN THE LONG TERM MODELS ON THE DEVELOPMENT AND TIMING
OF THE FRONT FROM THURSDAY AND ONWARD. THIS SAID...MAINLY KEPT
SLIGHT CHANCE POPS FROM MONDAY THROUGH WEDNESDAY FOR ISOLATED
ACTIVITY ACROSS THE NORTHERN COASTAL BEND AND COASTAL PLAINS...WITH
20-30 POPS INTRODUCED BY FRIDAY DUE TO PROXIMITY OF THE BOUNDARY.
TEMPERATURES FOR THE MOST PART WILL BE SLIGHTLY ABOVE NORMAL THROUGH
MUCH OF THE WEEK...WITH COOLER TEMPS TOWARD THE LATER OF THE WORK
WEEK MAINLY DUE TO THE INCREASED CLOUD COVERAGE AND RAIN CHANCES.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 94 79 94 77 94 / 20 10 10 10 20
VICTORIA 94 76 96 75 95 / 30 10 10 10 20
LAREDO 102 79 102 77 102 / 10 10 0 0 10
ALICE 97 76 98 75 98 / 20 10 10 10 10
ROCKPORT 91 80 91 79 90 / 30 10 10 10 20
COTULLA 101 77 101 75 102 / 10 10 0 0 10
KINGSVILLE 96 78 97 76 97 / 20 10 10 10 10
NAVY CORPUS 90 80 90 80 90 / 20 10 10 10 20
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
TB/78...SHORT TERM
CB/85...LONG TERM
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
747 AM EDT SAT SEP 5 2015
.SYNOPSIS...
A BACKDOOR COLD FRONT WILL DRIFT INTO FAR SOUTHWEST VIRGINIA AND
NORTHWEST NORTH CAROLINA BY EVENING AND STALL AS SURFACE HIGH
PRESSURE BUILDS SOUTHWESTWARD FROM THE NORTHERN MID-
ATLANTIC...ALLOWING FOR COOLER CONDITIONS TODAY AND CONFINING
THUNDERSTORMS TO WESTERN AREAS. LOW PRESSURE ALOFT WILL LINGER
ACROSS THE SOUTHEAST STATES OVER THE NEXT SEVERAL DAYS ALLOWING
WARM AND HUMID CONDITIONS ALONG WITH SCATTERED SHOWERS AND
THUNDERSTORMS TO RETURN TO THE ENTIRE AREA BY EARLY NEXT WEEK. A
STRONGER COLD FRONT WILL ARRIVE LATE NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 745 AM EDT SATURDAY...
PER HRRR...LIGHT TO MODERATE RAIN SHOWERS NOW DEVELOPING ALONG THE
LEADING EDGE OF THE ADVANCING BACKDOOR FRONT/WEDGE BOUNDARY NEAR
THE BLUE RIDGE. PREVIOUS POPS GENERALLY WELL ACCOUNTED FOR
THIS...BUT HAVE NUDGED THEM UP SLIGHTLY FURTHER EAST TO ACCOUNT
FOR THIS LATEST DEVELOPMENT. THIS ACTIVITY WILL ADVECT WEST TOWARD
THE ALLEGHANYS BY LATE MORNING/AFTERNOON...AT WHICH POINT SOME
THUNDERSTORMS WILL ALSO BEGIN TO DEVELOP ON THE EDGE OF THE
WEDGE/COOLER AIR. WIDESPREAD LOW CLOUDS ALSO DEVELOPING BEHIND THE
BACKDOOR FRONT AND EXTEND WELL NORTH INTO NORTHERN VA AND EAST
TOWARD THE COAST. HAVE INCREASED CLOUD COVER TO MOSTLY CLOUDY
THROUGHOUT THE DAY NEARLY ALL AREAS. NO SIGNIFICANT CHANGES TO
TEMPERATURE OR DEWPOINT READINGS NEEDED AT THIS TIME.
AS OF 415 AM EDT SATURDAY...
A CONVECTIVE OUTFLOW BOUNDARY FROM FRIDAY EVENING WIDESPREAD
THUNDERSTORM ACTIVITY APPEARS TO BE IN PLACE ACROSS FAR SOUTHWEST
VA/EASTERN TN/WESTERN NC...BUT THE TRUE BACKDOOR FRONT IS EVIDENT
JUST EAST OF THE BLUE RIDGE. NEAR THIS BACKDOOR FRONTAL
BOUNDARY...SPOTTY SHOWERS HAVE CONTINUED TO DEVELOP THROUGHOUT THE
NIGHT. HRRR AND LOCAL WRF MODELS SUPPORT A CONTINUATION OF THIS
PATTERN INTO THE MORNING...SHIFTING FURTHER WEST BY AFTERNOON. AT
THAT POINT...SUFFICIENT INSTABILITY WILL BE PRESENT FOR MORE
THUNDERSTORMS. CURRENT THINKING IS THAT A MORE STABLE AIR MASS
WILL SPREAD ACROSS THE PIEDMONT AND TOWARD THE ALLEGHANY FRONT BY
AFTERNOON...CONFINING THUNDERSTORMS TO THE I-77 CORRIDOR AND
POINTS WEST.
WITH A HEALTHY MARITIME EASTERLY FLOW DEVELOPING ACROSS AREAS
EAST OF THE ALLEGHANY FRONT IN THE WAKE OF THE BACKDOOR
FRONT...WIDESPREAD LOW CLOUDS ARE EXPECTED TO DEVELOP AND PERSIST
THROUGH MUCH OF THE DAY. THIS IS ALREADY EVIDENT ON THE LATEST
SATELLITE IMAGES. THESE CLOUDS WILL RESULT IN CONSIDERABLY COOLER
TEMPERATURES THAN WE HAVE SEEN IN RECENT DAYS ACROSS EASTERN PARTS
OF THE CWA...ESPECIALLY THE PIEDMONT WITH MAX AFTERNOON
TEMPERATURES STRUGGLING TO RISE OUT OF THE 70S...SOME 10-15
DEGREES COOLER THAN THE LAST SEVERAL DAYS. WEST OF THE I-77
CORRIDOR...TEMPERATURES ARE STILL EXPECTED TO BE QUITE WARM AND
NEAR TO ABOVE NORMAL...WITH AFTERNOON MAX TEMPS WELL INTO THE 80S
IN LOWER ELEVATIONS TOWARD THE TN BORDER...WITH 70S ACROSS THE
WESTERN MOUNTAINS.
THE WEDGE WILL PEAK OVERNIGHT AND INTO SUNDAY. LOW CLOUDS ARE
EXPECTED TO PERSIST INTO SUNDAY MORNING...WHICH WILL HOLD MIN
TEMPS CLOSER TO NORMAL VALUES FOR EARLY SEPTEMBER. ONLY LIMITED
SHOWER ACTIVITY IS EXPECTED OVERNIGHT IN THE FAR SOUTHWEST. CANNOT
COMPLETELY RULE OUT SOME LIGHT DRIZZLE ON THE EAST SIDE OF THE
ALLEGHANY FRONT (BCB-LWB AREA) EARLY SUNDAY...BUT NOT ENOUGH
CONFIDENCE TO INCLUDE IN THE GRIDS AT THIS TIME. FOG DEVELOPMENT
SUN MORNING SHOULD BE LIMITED BECAUSE OF CLOUDS AND WIDESPREAD
EASTERLY LOW-LEVEL FLOW.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
AS OF 300 AM EDT SATURDAY...
A PRETTY IMPRESSIVE HYBRID WEDGE FOR AUGUST WILL REMAIN OVER THE
EAST COAST SUNDAY...STRETCHING FROM NEW ENGLAND SOUTH INTO GEORGIA.
MODELS ARE USHERING IN MORE DRIER AIR WITH THE 00Z RUN...PLACING
HIGHER RAINFALL AMOUNTS OF A TENTH OF AN INCH /0.10/ OR MORE OVER
NORTH CAROLINA AND SOUTH. THE INTERACTION OF THE WEDGE BOUNDARY AND
A BROAD BUT WEAK UPPER LEVEL LOW OVER THE SOUTHEASTERN USA WILL KEEP
THE STRONGER CONVECTION OUT OF THE AREA. WE STILL CAN NOT RULE OUT
SOME SHOWERS AND THUNDERSTORMS AS WEAK IMPULSES TRACK AROUND THIS
LOW AND OVER THE AREA. THE COMBINATION OF EASTERLY FLOW AND A
STRONGER WEDGE WILL KEEP TEMPERATURES COOLER THAN NORMAL ALONG AND
EAST OF THE BLUE RIDGE SUNDAY AFTERNOON. DOWNSLOPE FLOW WILL HELP
WARM THE WEST WITH TEMPERATURES RUNNING ABOVE NORMAL. THE OVERALL
TEMPERATURE PICTURE FOR THE AREA WILL BE UNIFORM WITH SUNDAY`S
AFTERNOON HIGHS RANGING FROM THE UPPER 70S TO LOWER 80S.
ON MONDAY...THE PARENT HIGH OVER NEW ENGLAND WILL DRIFT
EAST...LEAVING A RESIDUAL BAGGY HIGH OVER THE MID ATLANTIC REGION.
MEANWHILE...THE UPPER LEVEL LOW RETROGRADES WEST ACROSS THE GULF
STATES. WITH THE DEPARTURE OF THE TWO MAIN WEATHER
FEATURES...AFTERNOON HEATING WILL GENERATE SCATTERED SHOWERS AND
THUNDERSTORMS OVER THE MOUNTAINS DURING THE AFTERNOON. THESE SLOW
MOVING STORMS COULD PRODUCE LOCALIZED HEAVY DOWNPOURS. THESE SHOWERS
WILL FADE WITH LOSE OF HEATING. MORE SUN IS EXPECTED MONDAY WHICH
WILL LEAD TO TEMPERATURES RETURNING TO NORMAL...ESPECIALLY ACROSS
THE PIEDMONT. HOWEVER...WITH LIGHT SOUTHEASTERLY FLOW...WE STILL
EXPECT UNIFORM TEMPERATURES IN THE LOW TO MID 80S ACROSS THE
AREA...UPPER 70S ALONG HIGHER RIDGES.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 330 PM EDT FRIDAY...
A GENERAL SUMMERTIME WEATHER PATTERN WILL RETURN FOR THE MIDDLE OF
NEXT WEEK...WITH SPOTTY SHOWERS AND THUNDERSTORMS DEVELOPING EARLY
EACH AFTERNOON WITH DAYTIME HEATING...AND DIMINISHING TOWARD SUNSET
AS HEATING ENDS. EXPECT ONLY SPOTTY COVERAGE OF RAINFALL ON TUESDAY
DUE TO WEAK SUPPORTING DYNAMICS...HOWEVER COVERAGE WILL INCREASE
EACH DAY FOR WEDNESDAY AND THURSDAY AS A COLD FRONT APPROACHES FROM
THE NORTHWEST.
BY NEXT THURSDAY...LONG RANGE WEATHER FORECAST MODELS DIFFER AS TO
WHERE THE COLD FRONT WILL BE LOCATED...WITH THE ECMWF MODEL BRINGING
THE FRONT ACROSS OUR AREA...WHILE THE GFS MODEL KEEPS THE FRONT WELL
TO OUR NORTH. GIVEN WHAT APPEARS TO BE WEAK UPPER LEVEL SUPPORT TO
GIVE THE FRONT A SOUTHWARD PUSH...HAVE TRENDED TOWARD THE GFS MODEL
AND TRIMMED BACK RAIN CHANCES FOR THAT DAY.
EXPECT WARM AND MUGGY CONDITIONS FOR THE PERIOD...WITH HIGHS RANGING
FROM THE UPPER 70S/LOW 80S ACROSS THE MOUNTAINS...TO THE UPPER 80S
FOR THE PIEDMONT. LOWS WILL HOLD GENERALLY IN THE LOW TO MID
60S...PERHAPS WITH A FEW UPPER 50S ACROSS THE MOUNTAINS.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 740 AM EDT SATURDAY...
TRUE BACKDOOR COLD FRONT LOCATED NEAR AN MRB-LYH-RDU LINE...WITH
MARITIME AIR NOW SURGING INTO THE EASTERN PART OF THE STATE. THIS
UPSLOPE MARITIME EASTERLY FLOW IS QUICKLY BEING REALIZED IN MVFR
CIGS AND MVFR VSBYS IN LOW CLOUDS AND FOG. ALSO...AS WELL DEPICTED
BY THE HRRR...PATCHES OF -SHRA/-DZ ALSO BEGINNING TO DEVELOP ALONG
THE LEADING EDGE OF THIS BOUNDARY...AND THIS ACTIVITY WILL
TRANSLATE WEST TOWARD THE ALLEGHANYS WITH THE BACKDOOR FRONT
THROUGH EARLY AFTERNOON. EXPECT WIDESPREAD MVFR...SOME IFR CIGS
ROA/LYH/DAN THROUGH 15Z...THROUGHOUT THE DAY. ANY IMPROVEMENT
DURING LATE AFTERNOON/EARLY EVENING...WILL QUICKLY DETERIORATEAGAIN
AFT 00Z. VSBYS ARE NOT EXPECTED TO GO BELOW MVFR CONDITIONS IN
THESE AREAS. PRECIPITATION EAST OF THE BLUE RIDGE WILL BE LIMITED
MOSTLY TO THIS MORNING.
TO THE WEST...LOW CLOUDS WERE ALSO ADVECTING/DEVELOPING INTO THE
REGION...BUT WILL LIKELY NOT PERSIST ALL DAY WEST OF THE BLUE
RIDGE. HOWEVER...NEAR THE ALLEGHANY FRONT AND I-77
CORRIDOR...GREATER POTENTIAL FOR SHOWERS/THUNDERSTORMS DURING THE
AFTERNOON...SO HAVE CONTINUED TO INCLUDE A VCTS AT BLF...BUT FEEL
THAT LWB/BCB WILL ESCAPE THIS. BETTER CHANCE FOR CONVECTION WILL
BE NEAR THE VA/NC/TN BORDER. CIGS MOSTLY MVFR IN THESE
AREAS...WITH SOME PERIOD OF VFR CIGS POSSIBLE DURING THE LATE
AFTERNOON/EARLY EVENING. THESE AREAS WILL SEE MVFR-IFR CIGS BY SUN
MORNING...HOWEVER WITH MVFR BR. EXCEPTION IS LWB...WHICH HAD
ENOUGH CLEARING FRI EVENING TO ALLOW LIFR FG TO DEVELOP AGAIN THIS
MORNING. THIS COULD PERSIST UNTIL AROUND 15
WINDS NE 6-9KTS WITH LOW END GUSTS...ESPECIALLY EAST OF THE BLUE
RIDGE LATE MORNING INTO MID-AFTERNOON.
MEDIUM CONFIDENCE IN CIGS THROUGH THE TAF VALID PERIOD.
MEDIUM CONFIDENCE IN VSBYS THROUGH THE TAF VALID PERIOD.
MEDIUM TO HIGH CONFIDENCE IN WIND SPD/DIR THROUGH THE TAF VALID
PERIOD.
MEDIUM CONFIDENCE IN TSRA POTENTIAL WEST THIS AFTERNOON.
EXTENDED AVIATION DISCUSSION...
HIGH PRESSURE WILL GRADUALLY WORK INTO THE REGION BY THE END OF
THE WEEKEND...AND REMAIN OVER THE AREA INTO THE EARLY PART OF
NEXT WEEK. LINGERING MOISTURE AND AN EASTERLY FETCH WILL HELP
MAINTAIN SOME ISOLATED TO SCATTERED SHOWERS ACROSS MAINLY WESTERN
PARTS OF THE AREA. THIS MOISTURE WILL BEGIN TO RETURN NORTH AND
EAST BY MONDAY WITH CHANCES FOR SHOWERS AND THUNDERSTORMS
INCREASING THROUGH MID-WEEK AS INSTABILITY INCREASES AND A COLD
FRONT APPROACHES FROM THE WEST.
PAST SATURDAY...CEILINGS AND VISIBILITIES WILL PRIMARILY BE
VFR OUTSIDE EARLY MORNING PATCHY DENSE FOG AND AFTERNOON
SHOWERS/THUNDERSTORMS.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...RAB
NEAR TERM...RAB
SHORT TERM...RCS
LONG TERM...NF
AVIATION...DS/RAB/WP
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
427 AM EDT SAT SEP 5 2015
.SYNOPSIS...
A BACKDOOR COLD FRONT WILL DRIFT INTO FAR SOUTHWEST VIRGINIA AND
NORTHWEST NORTH CAROLINA BY EVENING AND STALL AS SURFACE HIGH
PRESSURE BUILDS SOUTHWESTWARD FROM THE NORTHERN MID-
ATLANTIC...ALLOWING FOR COOLER CONDITIONS TODAY AND CONFINING
THUNDERSTORMS TO WESTERN AREAS. LOW PRESSURE ALOFT WILL LINGER
ACROSS THE SOUTHEAST STATES OVER THE NEXT SEVERAL DAYS ALLOWING
WARM AND HUMID CONDITIONS ALONG WITH SCATTERED SHOWERS AND
THUNDERSTORMS TO RETURN TO THE ENTIRE AREA BY EARLY NEXT WEEK. A
STRONGER COLD FRONT WILL ARRIVE LATE NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 415 AM EDT SATURDAY...
A CONVECTIVE OUTFLOW BOUNDARY FROM FRIDAY EVENING WIDESPREAD
THUNDERSTORM ACTIVITY APPEARS TO BE IN PLACE ACROSS FAR SOUTHWEST
VA/EASTERN TN/WESTERN NC...BUT THE TRUE BACKDOOR FRONT IS EVIDENT
JUST EAST OF THE BLUE RIDGE. NEAR THIS BACKDOOR FRONTAL
BOUNDARY...SPOTTY SHOWERS HAVE CONTINUED TO DEVELOP THROUGHOUT THE
NIGHT. HRRR AND LOCAL WRF MODELS SUPPORT A CONTINUATION OF THIS
PATTERN INTO THE MORNING...SHIFTING FURTHER WEST BY AFTERNOON. AT
THAT POINT...SUFFICIENT INSTABILITY WILL BE PRESENT FOR MORE
THUNDERSTORMS. CURRENT THINKING IS THAT A MORE STABLE AIR MASS
WILL SPREAD ACROSS THE PIEDMONT AND TOWARD THE ALLEGHANY FRONT BY
AFTERNOON...CONFINING THUNDERSTORMS TO THE I-77 CORRIDOR AND
POINTS WEST.
WITH A HEALTHY MARITIME EASTERLY FLOW DEVELOPING ACROSS AREAS
EAST OF THE ALLEGHANY FRONT IN THE WAKE OF THE BACKDOOR
FRONT...WIDESPREAD LOW CLOUDS ARE EXPECTED TO DEVELOP AND PERSIST
THROUGH MUCH OF THE DAY. THIS IS ALREADY EVIDENT ON THE LATEST
SATELLITE IMAGES. THESE CLOUDS WILL RESULT IN CONSIDERABLY COOLER
TEMPERATURES THAN WE HAVE SEEN IN RECENT DAYS ACROSS EASTERN PARTS
OF THE CWA...ESPECIALLY THE PIEDMONT WITH MAX AFTERNOON
TEMPERATURES STRUGGLING TO RISE OUT OF THE 70S...SOME 10-15
DEGREES COOLER THAN THE LAST SEVERAL DAYS. WEST OF THE I-77
CORRIDOR...TEMPERATURES ARE STILL EXPECTED TO BE QUITE WARM AND
NEAR TO ABOVE NORMAL...WITH AFTERNOON MAX TEMPS WELL INTO THE 80S
IN LOWER ELEVATIONS TOWARD THE TN BORDER...WITH 70S ACROSS THE
WESTERN MOUNTAINS.
THE WEDGE WILL PEAK OVERNIGHT AND INTO SUNDAY. LOW CLOUDS ARE
EXPECTED TO PERSIST INTO SUNDAY MORNING...WHICH WILL HOLD MIN
TEMPS CLOSER TO NORMAL VALUES FOR EARLY SEPTEMBER. ONLY LIMITED
SHOWER ACTIVITY IS EXPECTED OVERNIGHT IN THE FAR SOUTHWEST. CANNOT
COMPLETELY RULE OUT SOME LIGHT DRIZZLE ON THE EAST SIDE OF THE
ALLEGHANY FRONT (BCB-LWB AREA) EARLY SUNDAY...BUT NOT ENOUGH
CONFIDENCE TO INCLUDE IN THE GRIDS AT THIS TIME. FOG DEVELOPMENT
SUN MORNING SHOULD BE LIMITED BECAUSE OF CLOUDS AND WIDESPREAD
EASTERLY LOW-LEVEL FLOW.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
AS OF 300 AM EDT SATURDAY...
A PRETTY IMPRESSIVE HYBRID WEDGE FOR AUGUST WILL REMAIN OVER THE
EAST COAST SUNDAY...STRETCHING FROM NEW ENGLAND SOUTH INTO GEORGIA.
MODELS ARE USHERING IN MORE DRIER AIR WITH THE 00Z RUN...PLACING
HIGHER RAINFALL AMOUNTS OF A TENTH OF AN INCH /0.10/ OR MORE OVER
NORTH CAROLINA AND SOUTH. THE INTERACTION OF THE WEDGE BOUNDARY AND
A BROAD BUT WEAK UPPER LEVEL LOW OVER THE SOUTHEASTERN USA WILL KEEP
THE STRONGER CONVECTION OUT OF THE AREA. WE STILL CAN NOT RULE OUT
SOME SHOWERS AND THUNDERSTORMS AS WEAK IMPULSES TRACK AROUND THIS
LOW AND OVER THE AREA. THE COMBINATION OF EASTERLY FLOW AND A
STRONGER WEDGE WILL KEEP TEMPERATURES COOLER THAN NORMAL ALONG AND
EAST OF THE BLUE RIDGE SUNDAY AFTERNOON. DOWNSLOPE FLOW WILL HELP
WARM THE WEST WITH TEMPERATURES RUNNING ABOVE NORMAL. THE OVERALL
TEMPERATURE PICTURE FOR THE AREA WILL BE UNIFORM WITH SUNDAY`S
AFTERNOON HIGHS RANGING FROM THE UPPER 70S TO LOWER 80S.
ON MONDAY...THE PARENT HIGH OVER NEW ENGLAND WILL DRIFT
EAST...LEAVING A RESIDUAL BAGGY HIGH OVER THE MID ATLANTIC REGION.
MEANWHILE...THE UPPER LEVEL LOW RETROGRADES WEST ACROSS THE GULF
STATES. WITH THE DEPARTURE OF THE TWO MAIN WEATHER
FEATURES...AFTERNOON HEATING WILL GENERATE SCATTERED SHOWERS AND
THUNDERSTORMS OVER THE MOUNTAINS DURING THE AFTERNOON. THESE SLOW
MOVING STORMS COULD PRODUCE LOCALIZED HEAVY DOWNPOURS. THESE SHOWERS
WILL FADE WITH LOSE OF HEATING. MORE SUN IS EXPECTED MONDAY WHICH
WILL LEAD TO TEMPERATURES RETURNING TO NORMAL...ESPECIALLY ACROSS
THE PIEDMONT. HOWEVER...WITH LIGHT SOUTHEASTERLY FLOW...WE STILL
EXPECT UNIFORM TEMPERATURES IN THE LOW TO MID 80S ACROSS THE
AREA...UPPER 70S ALONG HIGHER RIDGES.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 330 PM EDT FRIDAY...
A GENERAL SUMMERTIME WEATHER PATTERN WILL RETURN FOR THE MIDDLE OF
NEXT WEEK...WITH SPOTTY SHOWERS AND THUNDERSTORMS DEVELOPING EARLY
EACH AFTERNOON WITH DAYTIME HEATING...AND DIMINISHING TOWARD SUNSET
AS HEATING ENDS. EXPECT ONLY SPOTTY COVERAGE OF RAINFALL ON TUESDAY
DUE TO WEAK SUPPORTING DYNAMICS...HOWEVER COVERAGE WILL INCREASE
EACH DAY FOR WEDNESDAY AND THURSDAY AS A COLD FRONT APPROACHES FROM
THE NORTHWEST.
BY NEXT THURSDAY...LONG RANGE WEATHER FORECAST MODELS DIFFER AS TO
WHERE THE COLD FRONT WILL BE LOCATED...WITH THE ECMWF MODEL BRINGING
THE FRONT ACROSS OUR AREA...WHILE THE GFS MODEL KEEPS THE FRONT WELL
TO OUR NORTH. GIVEN WHAT APPEARS TO BE WEAK UPPER LEVEL SUPPORT TO
GIVE THE FRONT A SOUTHWARD PUSH...HAVE TRENDED TOWARD THE GFS MODEL
AND TRIMMED BACK RAIN CHANCES FOR THAT DAY.
EXPECT WARM AND MUGGY CONDITIONS FOR THE PERIOD...WITH HIGHS RANGING
FROM THE UPPER 70S/LOW 80S ACROSS THE MOUNTAINS...TO THE UPPER 80S
FOR THE PIEDMONT. LOWS WILL HOLD GENERALLY IN THE LOW TO MID
60S...PERHAPS WITH A FEW UPPER 50S ACROSS THE MOUNTAINS.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
AS OF 145 AM EDT SATURDAY...
BACKDOOR COLD FRONT...LIKELY AIDED BY EVENING CONVECTION...APPEARS
TO BE NEAR A CRW- TRI- CLT LINE...DRIFTING SLOWLY WEST.
HOWEVER...THE TRUE BACKDOOR FRONT APPEARS TO BE NEAR THE BLUE
RIDGE. EVENING SHRA/TSRA ACTIVITY HAS GENERALLY DISSIPATED...BUT
AN ISOLATED SHRA/TSRA PERSISTS BETWEEN LYH AND ROA NEAR THE TRUE
BACKDOOR FRONTAL BOUNDARY. CANNOT TOTALLY RULE OUT AN ISOLD SHRA
TRACKING WEST TO NEAR ROA/BCB OVER THE NEXT FEW HOURS...BUT NOT
ENOUGH CONFIDENCE TO INCLUDE IN THE TAF. OTHERWISE...WITH LOSS OF
DAYTIME HEATING...NOT EXPECTING MUCH MORE OVERNIGHT EXCEPT FOR AN
OCCASIONAL SPRINKLE EAST OF THE BOUNDARY. MARITIME FLOW WILL
CONTINUE TO ADVECT INTO THE AREA FROM THE EAST AND IS EXPECTED TO
RESULT IN DETERIORATING CEILINGS IN THE 08Z-12Z TIME FRAME FROM
EAST TO WEST...ESPECIALLY EAST OF THE BLUE RIDGE. WIDESPREAD MVFR
CIGS ARE EXPECTED TO BE IN PLACE FOR ROA/LYH/DAN IN THIS TIME
FRAME...LINGERING INTO THE MID/LATE MORNING HOURS BEFORE IMPROVING
TO LOW END VFR CIGS. TO THE WEST...EARLIER RAINFALL AND
RADIATIONAL COOLING UNDER CURRENTLY MOSTLY CLEAR SKIES AT LWB WILL
ALLOW FOR DEVELOPMENT OF DENSE FOG...PAR FOR THE COURSE IN RECENT
DAYS. THIS WILL EVOLVE INTO AN MVFR CIG AFT 14Z...LINGERING
THROUGHOUT MUCH OF THE DAY. SIMILAR CONDITIONS EXPECTED AT
BCB...ALTHOUGH CONFIDENCE IN IFR-LIFR BR/FG LESS. FOR BLF...SKIES
ARE CURRENTLY CLEAR...BUT EAST FLOW SHOULD RESULT IN DEVELOPMENT
OF MVFR CIGS BY DAYBREAK...LINGERING THROUGHOUT MUCH OF THE DAY.
FOG DEVELOPMENT APPEARS LESS LIKELY THERE GIVEN EAST WINDS.
FINALLY...INSTABILITY/DEWPOINT BOUNDARY WILL RESIDE NEAR THE I-77
CORRIDOR BY PEAK AFTERNOON HEATING...WHICH COULD SUPPORT
THUNDERSTORMS IN THAT PART OF THE STATE AGAIN THIS AFTERNOON.
WINDS GENERALLY NE-E 6-10KTS WITH LOW END GUSTS AFTER DAYBREAK.
MEDIUM CONFIDENCE IN CIGS THROUGH THE TAF VALID PERIOD.
MEDIUM CONFIDENCE IN VSBYS THROUGH THE TAF VALID PERIOD.
MEDIUM TO HIGH CONFIDENCE IN WIND SPD/DIR THROUGH THE TAF VALID
PERIOD.
MEDIUM CONFIDENCE IN TSRA POTENTIAL WEST THIS AFTERNOON.
EXTENDED AVIATION DISCUSSION...
HIGH PRESSURE WILL GRADUALLY WORK INTO THE REGION BY THE END OF
THE WEEKEND...AND REMAIN OVER THE AREA INTO THE EARLY PART OF
NEXT WEEK. LINGERING MOISTURE AND AN EASTERLY FETCH WILL HELP
MAINTAIN SOME ISOLATED TO SCATTERED SHOWERS ACROSS MAINLY WESTERN
PARTS OF THE AREA. THIS MOISTURE WILL BEGIN TO RETURN NORTH AND
EAST BY MONDAY WITH CHANCES FOR SHOWERS AND THUNDERSTORMS
INCREASING THROUGH MID-WEEK AS INSTABILITY INCREASES AND A COLD
FRONT APPROACHES FROM THE WEST.
PAST SATURDAY...CEILINGS AND VISIBILITIES WILL PRIMARILY BE
VFR OUTSIDE EARLY MORNING PATCHY DENSE FOG AND AFTERNOON
SHOWERS/THUNDERSTORMS.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...RAB
NEAR TERM...RAB
SHORT TERM...RCS
LONG TERM...NF
AVIATION...DS/RAB/WP
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
647 PM CDT SUN SEP 6 2015
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 249 PM CDT SUN SEP 6 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A COLD
FRONT RUNNING SOUTHWEST FROM NORTHERN MINNESOTA TO EASTERN SOUTH
DAKOTA EARLY THIS AFTERNOON. DESPITE ML CAPES UPWARDS OF 2000 J/KG
OVER CENTRAL MINNESOTA...THE FRONT IS MOSTLY INACTIVE AS A RESULT OF
CIN GREATER THAN 100 J/KG. STILL RATHER UNCERTAIN HOW CONVECTION
WILL EVOLVE LATER THIS AFTERNOON. MOST MESOMODELS SHOW CONVECTION
DEVELOPING AFTER 21Z...BUT THIS WILL BE AROUND THE SAME TIME AS THE
RIGHT FRONT QUAD OF A JET STREAK MOVES OVERHEAD. AS A
RESULT...THINK CONVECTION WILL NOT BE AS ROBUST AS THE ARW/NMM...AND
MORE ISOLATED TO SCATTERED LIKE THE HRRR. OTHERWISE...THE MID-LEVEL
THETAE AND PWAT PLUME WILL CONTINUE TO PUSH IN SCATTERED LIGHT
SHOWERS AND ISOLATED TSTORMS FOR THE REST OF THE AFTERNOON INTO
CENTRAL AND N-C WISCONSIN. TEMPS MAY NOT GET TO THEIR EARLIER
FORECAST HIGHS IN THESE AREAS AS A RESULT. AS THE COLD FRONT MOVES
EAST TONIGHT...THUNDERSTORMS CHANCES AND IMPACTS ARE THE MAIN
FORECAST CONCERNS.
TONIGHT...THE COLD FRONT WILL MOVE EAST TONIGHT...REACHING N-C
WISCONSIN BY 06Z AND NORTHEAST WISCONSIN BY 12Z. AT LEAST SCT
CONVECTION STILL LOOKS TO FIRE OVER MINNESOTA...BUT THINK IT WILL
REMAIN RATHER UNORGANIZED TO THE LARGE CIN AND UPPER LEVEL
SUBSIDENCE. BUT AS THE FRONT DRAWS CLOSER TO THE PWAT PLUME OVER
WESTERN WISCONSIN...THE ECMWF/GFS/GEM ALL DEVELOP WIDESREAD SHOWERS
AND STORMS AFTER 00Z. ALONG WITH PWATS GREATER THAN 2.0
INCHES...ELEVATED INSTABILITY WILL REACH 1000-2000 J/KG WITH LITTLE
TO NO CIN. SO WENT WITH THIS IDEA IN THE FORECAST...INCREASING
PRECIP CHANCES QUICKLY IN THE 00-03Z TIME PERIOD. PRECIP IS
EXPECTED TO WEAKEN SOME BY THE TIME IT REACHES THE LAKE MICHIGAN
SHORELINE LATE TONIGHT. SINCE EFFECTIVE BULK SHEARS WILL GENERALLY
BE UNDER 20 KTS BY THE TIME CONVECTION DEVELOPS...THINK ANY SEVERE
THREAT IS RATHER LOW. ISOLATED STRONG GUSTY WINDS STILL APPEAR
REASONABLE...ALONG WITH LOCALLY HEAVY RAINFALL.
MONDAY...THE FRONT WILL STILL BE BISECTING THE FORECAST AREA FROM NE
WI TO CENTRAL WI AT THE START OF THE MORNING. SCT SHOWERS AND
STORMS WILL BE POSSIBLE ALONG THE FRONT OVER CENTRAL AND FAR NE
WISCONSIN DURING THE MORNING...AND EAST-CENTRAL WI THROUGH LATE
AFTERNOON. CLOUD COVER SHOULD BE WIDESPREAD AHEAD OF THE
FRONT...BUT IF CLOUDS DO BREAK FOR A PERIOD...INSTABILITY OVER EAST-
CENTRAL WI COULD BECOME SUFFICIENT FOR STRONG STORMS TO DEVELOP.
SEVERE STORMS ARE UNLIKELY GIVEN THE POOR SHEAR OF 15-20KTS. BEHIND
THE FRONT...N-C WI SHOULD SEE CLEARING TAKE PLACE IN THE AFTERNOON
AFTER A CLOUDY START. COOLER HIGHS IN THE MID 70S TO LOW 80S.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 249 PM CDT SUN SEP 6 2015
THE COLD FRONT WILL MAKE IT INTO SOUTHERN WISCONSIN OR NORTHERN
ILLINOIS MONDAY NIGHT BEFORE RETURNING NORTHWARD AS A WAVE MOVES
NORTHEAST ALONG THE FRONT. THE FRONT WILL BE SHALLOW SO THERE WILL
LIKELY BE OVERRUNNING SHOWERS AND THUNDERSTORMS ACROSS THE
SOUTHEAST HALF OF THE FORECAST AREA TUESDAY. THE FRONT SHOULD MOVE
FAR ENOUGH SOUTH WEDNESDAY FOR DRIER AIR TO RETURN FOR AWHILE. IT
WILL ALSO BE COOLER AND LESS HUMID.
AN UPPER TROUGH WILL MOVE ACROSS THE REGION THURSDAY AND BRING A
CHANCE OF SHOWERS FOLLOWED BY NORTHWEST UPPER FLOW AND MUCH COOLER
AND DRIER AIR FOR THE REMAINDER OF THE WEEK. LOWS IN THE 30S ARE
POSSIBLE IN FAR NORTHERN WISCONSIN FRIDAY NIGHT.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 639 PM CDT SUN SEP 6 2015
A WEAKENING LINE OF TSTMS WITH GUSTY WINDS AND HEAVY RAIN WILL
SHIFT INTO EASTERN WI THIS EVG. ANOTHER ROUND OF STORMS SHOULD
DEVELOP AHEAD OF A COLD FRONT LATER THIS EVG...AND MOVE THROUGH
OVERNIGHT. MVFR/IFR CONDITIONS SHOULD ACCOMPANY THESE STORMS. LOW
CLOUDS (POSSIBLE IFR/LIFR) MAY ACCOMPANY THE FRONTAL PASSAGE AND
LINGER INTO MONDAY MORNING BEFORE ERODING/LIFTING.
KEPT LLWS IN THE GRB/ATW/MTW TAFS THIS EVG...WITH SW WINDS AROUND
35 KTS AROUND 1500 FT AGL.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
BEACH HAZARDS STATEMENT UNTIL 8 PM CDT THIS EVENING FOR WIZ022.
&&
$$
SHORT TERM.....MPC
LONG TERM......RDM
AVIATION.......KIECKBUSCH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
328 PM CDT SAT SEP 5 2015
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 328 PM CDT SAT SEP 5 2015
SURFACE OBSERVATIONS ACROSS THE REGION THIS AFTERNOON INDICATE A
STATIONARY FRONT POSITIONED FROM NEAR MANKATO MINNESOTA EAST TO THE
MISSISSIPPI RIVER EXTENDING SOUTHEAST THROUGH SOUTHWEST WISCONSIN. A
LOW LEVEL JET WAS FOCUSED INTO THE FRONT EARLIER TODAY AND
PRODUCED SHOWERS AND THUNDERSTORMS ACROSS PORTIONS OF SOUTHERN
MINNESOTA. THE SHOWERS AND STORMS GRADUALLY WEAKENED LATE THIS
MORNING AND ENDED EARLY THIS AFTERNOON. ABUNDANT MID TO HIGH LEVEL
CLOUDS WERE ACROSS THE FORECAST AREA TODAY THANKS TO THIS EARLY
DAY CONVECTION ACROSS MINNESOTA. FURTHER TO THE SOUTH...PARTLY TO
MOSTLY SUNNY SKIES HAVE ALLOWED TEMPERATURES TO SOAR INTO THE
UPPER 80S TO LOWER 90S ACROSS PORTIONS OF EASTERN AND NORTHERN
IOWA. INCREASING SOUTHERLY FLOW IS ADVECTING THIS WARMER AIR INTO
THE FORECAST AREA. IN ADDITION...WE ARE SEEING SOME
BREAKS/THINNING IN THE CLOUD COVER SO TEMPERATURES ARE GRADUALLY
WARMING ACROSS MUCH OF THE FORECAST AREA WITH MANY LOCATIONS
ALREADY CLIMBING INTO THE MID TO UPPER 80S. LOOK FOR THESE
TEMPERATURES TO CONTINUE TO CLIMB THIS AFTERNOON WITH HIGHS
RANGING FROM THE MID 80S ACROSS NORTHERN WISCONSIN TO AROUND 90S
ACROSS PORTIONS OF NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN.
LOW PRESSURE WILL TRACK FROM SOUTH DAKOTA INTO SOUTHWEST ONTARIO
TONIGHT THROUGH SUNDAY PUSHING A COLD FRONT TOWARDS THE FORECAST
AREA. ALSO...FLOW ALOFT WILL GRADUALLY TURN SOUTHWEST TONIGHT
INTO SUNDAY MORNING WITH A COUPLE OF WEAK SHORTWAVE TROUGHS MOVING
THROUGH. THESE WAVES COMBINED WITH WEAK MOISTURE TRANSPORT INTO
THE REGION MAY GENERATE ISOLATED SHOWERS AND THUNDERSTORMS
TONIGHT INTO SUNDAY MORNING. IF THESE DEVELOP...THEY WOULD MAINLY
BE FOCUSED ACROSS PORTIONS OF NORTHEAST IOWA...SOUTHEAST MINNESOTA
INTO PORTIONS OF WEST CENTRAL WISCONSIN. THE COLD FRONT WILL SLIDE
INTO THE FORECAST AREA BY SUNDAY AFTERNOON WITH SHOWERS AND STORMS
EXPECTED TO ERUPT ALONG THE FRONT. MESOSCALE MODELS ARE SHOWING
SOME DIFFERENCES IN TIMING THE FRONT INTO THE AREA. THE HI-RES ARW
IS INITIATING CONVECTION ACROSS WESTERN SECTIONS OF THE FORECAST
AREA BY MID AFTERNOON. THE LINE OF CONVECTION THEN SLIDES
SOUTHEAST THROUGH LATE AFTERNOON INTO THE EARLY EVENING HOURS AND
WEAKENS WITH TIME. THE HI-RES NMM JUST WEST OF THE FORECAST AREA
LATE IN THE AFTERNOON AND THEN TAKES THE LINE OF CONVECTION
EAST...SIMILAR TO THE ARW...BUT THEN ATTEMPTS TO SPLIT THE
CONVECTION INTO TWO SEGMENTS. ONE SEGMENT TRACKS ACROSS NORTH
CENTRAL WISCONSIN AND THE SECOND DIVES SOUTH INTO CENTRAL IOWA.
THE NAM NEST OFFERS A SIMILAR SOLUTION TO THE NMM. CAPE VALUES
WANE CONSIDERABLY EAST OF THE MISSISSIPPI RIVER SUNDAY EVENING SO
THINKING ANY CHANCES OF SEEING A FEW STRONG TO PERHAPS SEVERE
STORMS WOULD BE WEST OF THE MISSISSIPPI RIVER MAINLY DURING THE
MID TO LATE AFTERNOON ON SUNDAY. ALSO...SHEAR IS RATHER WEAK
ACROSS THE FORECAST AREA SUNDAY AFTERNOON INTO SUNDAY NIGHT WITH
0-3 KM BULK SHEAR VALUES IN THE 15 TO 20 KT RANGE. WE SHOULD SEE A
BROKEN LINE OF SHOWERS AND STORMS PUSH ACROSS THE FORECAST AREA
SUNDAY AFTERNOON INTO SUNDAY NIGHT...WITH A GRADUAL WEAKENING
TREND DURING THE EVENING INTO THE OVERNIGHT HOURS AS CAPE WANES.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 328 PM CDT SAT SEP 5 2015
THE COLD FRONT STALLS ACROSS NORTHERN IOWA INTO NORTHERN ILLINOIS MONDAY
INTO TUESDAY AS ANOTHER SHORTWAVE EJECTS OUT OF THE DESERT
SOUTHWEST. THIS WILL BRING A GOOD CHANCE OF SHOWERS AND STORMS TO
THE FORECAST AREA..ESPECIALLY FOR AREAS ALONG AND SOUTH OF
INTERSTATE 90. IN FACT...SOME HEAVY RAINFALL IS POSSIBLE ALONG THE
FRONT ACROSS CENTRAL IOWA INTO NORTHERN ILLINOIS. AT THIS
TIME...IT APPEARS THE FORECAST AREA WILL BE UNDER THE RIGHT
ENTRANCE REGION OF THE UPPER JET...PROVIDING SUPPORT FOR SHOWERS
AND EMBEDDED THUNDERSTORMS FROM LATE MONDAY INTO TUESDAY. THE
FRONT FINALLY PUSHES SOUTH OF THE REGION TUESDAY NIGHT INTO
WEDNESDAY WITH DRY HIGH PRESSURE BUILDING INTO THE UPPER
MISSISSIPPI RIVER VALLEY. A TROUGH THEN LOOKS TO PUSH THROUGH THE
REGION WEDNESDAY INTO THURSDAY CARVING OUT A MUCH BROADER TROUGH
ACROSS THE UPPER MISSISSIPPI RIVER VALLEY FOR LATE NEXT WEEK. ITS
LOOKING LIKE WE WILL SEE MUCH COOLER TEMPERATURES TO END NEXT WEEK
AS THIS TROUGH TAKES SHAPE. HIGHS FROM THURSDAY ALL THE WAY INTO
THE WEEKEND LOOK TO BE IN THE 60S WITH CHANCES FOR SHOWERS. IT
APPEARS FALL WEATHER WILL MAKE ITS APPEARANCE LATE NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1155 AM CDT SAT SEP 5 2015
CONVECTION OVER SOUTHERN MN HAS BEEN RELUCTANT TO DIE LATE THIS
MORNING...BEING FUELED BY THE LOW LEVEL JET/MOISTURE TRANSPORT. SOME
SIGNS THAT IT WAS WANING...BUT IT COULD LAST LONGER INTO THE
AFTERNOON THAN MESO MODELS SUGGEST - WHICH WEREN/T DOING A GREAT JOB
WITH IT ANYWAY. ULTIMATELY...DON/T THINK IT WILL IMPACT KRST ASIDE
FROM A VEIL OF MID/UPPER LEVEL CLOUDS...WHICH WILL ALSO HOLD ACROSS
KLSE.
TONIGHT SEE SOME POTENTIAL FOR ISOLATED SHRA/TS DEVELOPMENT. HINTS
IN THE RAP ON A BRANCH OF THE LOW LEVEL JET EDGING OVER THE LOCAL
AREA...WITH WEAK INSTABILITY A LOFT AND A MOISTURE FEED. NOT GOING TO
INCLUDE IN THE FORECAST AT THIS TIME...BUT THE POTENTIAL WILL HAVE
TO BE MONITORED.
SHRA/TS ARE LIKELY SUNDAY NIGHT AS A COLD FRONT SWEEPS IN FROM THE
WEST.
ONE LAST POTENTIAL CONCERN FOR TONIGHT IS THE POSSIBILITY OF LLWS.
RAP/HRRR/NAM BUFKIT SOUNDINGS ALL SUGGESTING BETWEEN 35-40 KTS BY
1500 FT. BORDERLINE LLWS IF SFC WINDS STAY UP TONIGHT AS FORECAST.
IF NOT...MAY NEED TO BE ADDED TO THE FORECAST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION.....RIECK
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND SUNDAY
ISSUED AT 251 PM CDT SAT SEP 5 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW LOW
PRESSURE CENTERED OVER NORTHWEST ONTARIO AND A CONNECTING COLD FRONT
RUNNING SOUTHWEST FROM THE LOW ACROSS THE DAKOTAS. AHEAD OF THE
FRONT...SHOWERS AND STORMS ARE OCCURRING WITH HELP FROM A SHORTWAVE
TROUGH. CLOSER TO HOME...A WEAK ELEVATED FRONT REMAINS OVER NE
WISCONSIN...AND CONTINUES TO KICK OFF ISOLATED SHOWERS. THE THREAT
FOR SHOWERS SHOULD COME TO AN END BY LATE THIS AFTERNOON AS THIS
BOUNDARY EXITS. AS THE SHORTWAVE ARRIVES LATE TONIGHT...FOLLOWED BY
THE COLD FRONT LATE ON SUNDAY...SHOWER AND THUNDERSTORM CHANCES ARE
THE MAIN FORECAST CONCERN.
TONIGHT...MID-LEVEL RIDGING WILL HANG OVERHEAD FOR MUCH OF THE
NIGHT. SOUTHWEST MID-LEVEL WINDS WILL ADVECT IN CLOUDS GENERALLY
ABOVE 12KFT THAT ARE CURRENTLY OVER SOUTHWEST WISCONSIN FOR THE
EVENING. THEN THE TAIL END OF A SHORTWAVE WHICH WILL LIFT INTO
ONTARIO WILL GRAZE NORTH-CENTRAL WISCONSIN OVERNIGHT. THIS
SHORTWAVE IN COMBINATION WITH INCREASING MID-LEVEL THETAE AND LLJ
MAY GENERATE A FEW SHOWERS AND STORMS OVER N-C WISCONSIN LATE.
CONFIDENCE IS RATHER LOW SO WILL KEEP PRECIP CHANCES AT OR BELOW 30
PCT. THE PRESSURE GRADIENT WILL BE TIGHTENING SO SHOULD SEE A
STEADY SOUTHEAST TO SOUTH WIND THROUGH THE NIGHT. THIS SHOULD
PROHIBIT DENSE FOG FROM FORMING...EXCEPT NEAR LAKE MICHIGAN WHERE
ONSHORE FLOW WILL BE OCCURRING. MUGGY LOWS IN THE UPPER 60S TO LOW
70S.
SUNDAY...A CHANCE OF SPOTTY SHOWERS AND STORMS WILL CONTINUE THROUGH
THE MORNING...MAINLY OVER N-C WISCONSIN...THOUGH AM NOT EXPECTING
MUCH ACTIVITY UNTIL INSTABILITY INCREASES LATER IN THE DAY. AS A
COLD FRONT MOVES INTO THE NORTHERN MISSISSIPPI VALLEY...THE PWAT
PLUME IN EXCESS OF 2.0 INCHES WILL SPREAD EAST ACROSS CENTRAL AND
NORTH-CENTRAL WISCONSIN DURING THE AFTERNOON. CONVECTIVE TEMPS WILL
ONLY BE IN THE MID 80S...AND PROGGED SOUNDINGS INDICATE LITTLE
CAPPING WHILE ML CAPES REACH TO AROUND 2000 J/KG. SO CONDITIONS
LOOK GOOD FOR SCT THUNDERSTORM DEVELOPMENT BY MID-AFTERNOON. WINDS
ALOFT ALSO INCREASE LATE IN THE AFTERNOON...WHICH COULD GIVE AN
ISOLATED DAMAGING WIND THREAT WITHIN ANY THUNDERSTORMS.
OTHERWISE...THE SKINNY CAPES AND HIGH PWATS SHOULD PRODUCE HEAVY
RAIN MAKERS. VERY WARM AND MUGGY WITH HIGHS RANGING FROM THE MID
80S NORTH TO NEAR 90 SOUTH.
.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY
ISSUED AT 251 PM CDT SAT SEP 5 2015
A COLD FRONT SHOULD MOVE SLOWLY ACROSS WISCONSIN SUNDAY NIGHT AND
BECOME STATIONARY OVER NORTHERN ILLINOIS MONDAY. MODEL THEN BRING
A SURFACE WAVE NORTHEAST AND PUSH THE FRONT BACK NORTH TUESDAY.
THERE ARE DIFFERENCES IN THE TIMING AND NORTHWARD EXTENT OF THE
SHOWERS AND THUNDERSTORMS ASSOCIATED WITH THE FEATURE BUT IT LOOKS
LIKE THE BULK OF THE PRECIPITATION WILL BE ACROSS THE SOUTHEAST
HALF OF OUR FORECAST AREA.
THE FRONT GETS A SHOVE TO THE SOUTH TUESDAY NIGHT WITH DRY AND
COOLER CONDITIONS EXPECTED WEDNESDAY THROUGH PART OF THURSDAY
BEFORE AN UPPER TROUGH SWINGS THROUGH WITH POSSIBLE SHOWERS
THURSDAY NIGHT AND FRIDAY. TEMPERATURES WILL REMAIN WARMER THAN
NORMAL THROUGH THE MIDDLE OF THE WEEK AND THEN FALL TO NORMAL OR
EVEN A BIT COOLER THAN NORMAL BY THE END OF THE WEEK AS HEIGHTS
FALL.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1200 PM CDT SAT SEP 5 2015
ISOLATED SHOWERS ARE POSSIBLE ALONG A WEAK BOUNDARY THAT
WILL RETREAT TO THE NORTHEAST OVER NORTHEAST WISCONSIN THROUGH MID-
AFTERNOON. THEREAFTER...WILL GRADUALLY SEE AN INCREASE OF MID-
CLOUDS. THE COMBO OF CLOUDS AND A SOUTHERLY BREEZE SHOULD PREVENT
WIDESPREAD FOG FROM FORMING...EXCEPT ALONG LAKE MICHIGAN. DID BACK
OFF FOG IMPACTS AS STATISTICAL AND UPS FOG TECHINIQUE ARE MORE
OPTIMISTIC. ANY LOWER VSBYS SHOULD IMPROVE QUICKLY SUNDAY MORNING.
THE CHANCE OF SHOWERS AND STORMS THOUGH WILL INCREASE WITH HEATING
OF THE DAY ON SUNDAY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......RDM
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1155 AM CDT SAT SEP 5 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 250 AM CDT SAT SEP 5 2015
FORECAST FOCUS IS ON RAIN CHANCES TODAY WITH WEAK DISTURBANCE
MOVING THROUGH THE REGION. AMOUNT OF CLOUD COVER AND RESULTING
TEMPERATURES THEN ON THE FOREFRONT.
REGIONAL RADAR LOOPS SHOW NARROW BAND OF SHOWERS MOVING SLOWLY
EAST THROUGH THE FORECAST AREA...LOCATED RIGHT ALONG THE
MISSISSIPPI RIVER AT 07Z. THIS OCCURRING IN A FAVORABLE
THERMODYNAMIC FORCING RIBBON. THIS EXPECTED TO TRANSLATE EAST
AND WEAKEN WITH TIME THIS MORNING. ONCE THIS AREA MOVES OFF...
HAZY SUNSHINE AND HUMID CONDITIONS WILL ONCE AGAIN PREVAIL SIMILAR
TO THE PAST FEW DAYS. MODELS ALL POINT TO ANOTHER WEAK SHORT WAVE
TROUGH MOVING NORTHEAST UP THE RIDGE AND INTO WESTERN MN BY
EVENING. THIS SHOULD HELP FIRE CONVECTION TO THE WEST OF THE
FORECAST AREA...AND SOME OF THIS COULD TRY AND SNEAK IN TO THE
WESTERN FRINGES OF OUR FORECAST AREA OVERNIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 250 AM CDT SAT SEP 5 2015
A PATTERN SHIFT WILL TAKE PLACE AS THE UPPER RIDGE SHIFTS EAST AND
FLATTENS IN RESPONSE TO THE LARGER WESTERN LONG WAVE TROUGH
OPENING AND EJECTING NORTHEAST INTO SOUTHERN CANADA BY SUNDAY. AS
THE FORCING FROM THE MAIN WAVE PASSES...IT SENDS A COLD FRONT
THROUGH THE LOCAL AREA LATE SUNDAY. WARM AIR AND DEEP MIXING AHEAD
OF THE FRONT WILL KEEP TEMPERATURES AND HEAT INDEX VALUES UP FOR
ONE LAST DAY. CAPE IS EXPECTED TO RISE TO 1500-2000 J/KG BUT SHEAR
WILL BE LIMITED...LAGGING THE FRONTAL PASSAGE. SOME STRONG STORMS
ARE POSSIBLE BUT NOT VERY CONFIDENT IN ANY SIGNIFICANT SEVERE
POTENTIAL. RAIN WILL END AND MUCH MORE SEPTEMBER-LIKE TEMPERATURES
ANTICIPATED BEHIND THE FRONT NEXT WEEK. AS UPPER FLOW BECOMES
ZONAL TO SLIGHTLY NORTHWEST...SOME WEAK RIPPLES WILL BE
TRANSITIONING THROUGH THE AREA. ONE SUCH DISTURBANCE MAY BRING
RAIN MONDAY NIGHT AND TUESDAY...WITH ANOTHER WEDNESDAY NIGHT INTO
THURSDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1155 AM CDT SAT SEP 5 2015
CONVECTION OVER SOUTHERN MN HAS BEEN RELUCTANT TO DIE LATE THIS
MORNING...BEING FUELED BY THE LOW LEVEL JET/MOISTURE TRANSPORT. SOME
SIGNS THAT IT WAS WANING...BUT IT COULD LAST LONGER INTO THE
AFTERNOON THAN MESO MODELS SUGGEST - WHICH WEREN/T DOING A GREAT JOB
WITH IT ANYWAY. ULTIMATELY...DON/T THINK IT WILL IMPACT KRST ASIDE
FROM A VEIL OF MID/UPPER LEVEL CLOUDS...WHICH WILL ALSO HOLD ACROSS
KLSE.
TONIGHT SEE SOME POTENTIAL FOR ISOLATED SHRA/TS DEVELOPMENT. HINTS
IN THE RAP ON A BRANCH OF THE LOW LEVEL JET EDGING OVER THE LOCAL
AREA...WITH WEAK INSTABILITY A LOFT AND A MOISTURE FEED. NOT GOING TO
INCLUDE IN THE FORECAST AT THIS TIME...BUT THE POTENTIAL WILL HAVE
TO BE MONITORED.
SHRA/TS ARE LIKELY SUNDAY NIGHT AS A COLD FRONT SWEEPS IN FROM THE
WEST.
ONE LAST POTENTIAL CONCERN FOR TONIGHT IS THE POSSIBILITY OF LLWS.
RAP/HRRR/NAM BUFKIT SOUNDINGS ALL SUGGESTING BETWEEN 35-40 KTS BY
1500 FT. BORDERLINE LLWS IF SFC WINDS STAY UP TONIGHT AS FORECAST.
IF NOT...MAY NEED TO BE ADDED TO THE FORECAST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...MW
LONG TERM....MW
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1144 AM MDT SAT SEP 5 2015
.UPDATE...
ISSUED AT 951 AM MDT SAT SEP 5 2015
A FEW LIGHT SHOWERS AND SPRINKLES MOVING ACROSS NORTHERN PORTIONS
OF THE NEBRASKA PANHANDLE AT THIS TIME. THIS AREA OF SHOWERS WILL
QUICKLY MOVE OUT OF THE AREA BEFORE MORNINGS END BUT MORE SHOWER
ACTIVITY TO DEVELOP ACROSS THE FORECAST AREA THIS AFTERNOON.
UPDATED POP AND SKY COVER FORECAST TO REFLECT CURRENT CONDITIONS
AND TWEAKED CHANCES FOR SHOWERS AND THUNDERSTORMS THIS AFTERNOON.
BASED ON THE HRRR MODEL PERFORMANCE THE LAST FEW DAYS...ADDED
ISOLATED SHOWERS AND THUNDERSTORMS TO THE ENTIRE WESTERN NEBRAKSA
PANHANDLE THIS AFTERNOON.
ONCE AGAIN VERY LITTLE IN THE WAY OF MEASURABLE PRECIPITATION IS
EXPECTED. MAINLY LOOKING FOR A TRACE TO A FEW HUNDRETHS OF AN INCH
OF PRECIPITATION WITH LOCALLY HIGHER AMOUNTS WITH ANY THUNDERSTORM
ACTIVITY. THUNDERSTORMS WILL BE FEW AND FAR BETWEEN. INVERTED V
SOUNDINGS WILL ONCE AGAIN SUGGESTIVE OF GUSTY DOWNDRAFT/OUTFLOW
WINDS WITH SOME SHOWERS AND THUNDERSTORMS TODAY. GUSTS OF 40 TO 50
MPH LIKELY WITH SOME SHOWERS AND THUNDERSTORMS.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 303 AM MDT SAT SEP 5 2015
PREDAWN WATER VAPOR IMAGERY DEPICTED A UPPER TROUGH OVER THE
NORTHWEST CONUS WITH A LOW CENTERED OVER OR. A LARGE UPPER RIDGE
ENCOMPASSED THE EASTERN 2/3 OF THE NATION. SUBTROPICAL/MONSOON
MOISTURE CONTINUED TO STREAM NORTHEAST FROM BAJA CA INTO THE
ROCKIES AND HIGH PLAINS. A PASSING WEAK SHORT WAVE OVER FAR
SOUTHEAST WY AND WESTERN NE PRODUCED SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS. THIS ACTIVITY WILL END BY DAYBREAK. SKIES
WERE MOSTLY CLOUDY WITH LIGHT WINDS AND TEMPERATURES IN THE 50S
AND 60S.
THE SHORT RANGE MODELS HAVE MAINTAINED THEIR RUN-TO-RUN CONSISTENCY
FOR SEVERAL DAYS PROGGING THE PACIFIC NORTHWEST UPPER LOW TO LIFT
NORTHEAST THROUGH ID AND MT DURING THE NEXT 24 HOURS. THE MOIST
SOUTHWEST FLOW ALOFT WILL PROVIDE CHANCES FOR SHOWERS AND ISOLATED
THUNDERSTORMS FROM LATE THIS MORNING THROUGH THE AFTERNOON AND
EVENING...ESPECIALLY WEST OF I-25. GUSTY WINDS UP TO 45 MPH...
LIGHTNING AND BRIEF MODERATE TO HEAVY RAIN WILL BE THE PRIMARY
HAZARDS. OUTSIDE OF THE CONVECTION...SOUTHWEST WINDS WILL GUST TO
35 MPH WEST OF THE LARAMIE RANGE. IT WILL BE ANOTHER WARM AFTERNOON
FOR THE PLAINS WITH HIGHS IN THE 80S TO AROUND 90.
A PACIFIC COLD FRONT IS FORECAST TO MOVE EAST ACROSS THE CWA LATE
TONIGHT AND EARLY SUNDAY MORNING...USHERING IN A DRIER AND MORE
STABLE AIR MASS. WEST TO NORTHWEST WINDS WILL INCREASE TO 25 TO
35 MPH BEHIND THE FRONT SUNDAY MORNING...WITH HIGHER GUSTS
POSSIBLE IN WIND PRONE AREAS OF SOUTHEAST WY. SUNDAY WILL BE 5 TO
10 DEGREES COOLER WITH HIGHS IN THE 70S TO LOWER 80S.
MONDAY WILL BE A PLEASANT DAY WITH NEAR SEASONABLE TEMPERATURES. A
WEAK SURFACE TROUGH IS PROGGED BY MOST OF THE MODELS TO SET UP NEAR
THE WY-NE BORDER MONDAY WITH A FEW SHOWERS OR THUNDERSTORMS POSSIBLE
OVER THE FAR SOUTHEAST PART OF THE CWA...ROUGHLY EAST OF A ALLIANCE
TO SIDNEY LINE. BREEZY WEST WINDS WILL DEVELOP ALONG AND WEST OF
THE LARAMIE RANGE MONDAY AFTERNOON.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 300 AM MDT SAT SEP 5 2015
A LOW AMPLITUDE CYCLONIC UPPER FLOW SHOULD EXIST OVER SRN CANADA
AND THE NORTHERN TIER STATES MOST OF NEXT WEEK. SEVERAL UPPER
SHORT WAVES WILL TRANSLATE EAST ACROSS THE REGION IN THIS FLOW
PATTERN BRINGING SURGES OF COOLER AIR. ONE MINOR FRONT WILL SCOOT
ACROSS MONDAY NIGHT BUT HAVE LITTLE EFFECT ON THE SENSIBLE WEATHER
ACROSS THE CWA WITH WARM AND DRY WEATHER EXPECTED FOR TUESDAY AND
WEDS. A LITTLE STRONGER FRONT LOOKS TO PASS ACROSS LATER WEDS BUT
AGAIN LOOKS DRY. MILD TEMPS THURSDAY THEN A STRONGER SHORTWAVE
WILL MOVE SOUTHEAST OUT OF SOUTHERN CANADA INTO THE PLAINS THURSDAY
NIGHT DRIVING YET ANOTHER PUSH OF COOLER AIR SOUTH OUT OF CANADA
AND REINFORCING THE MILD AIR MASS OVER THE REGION. THIS SYSTEM MAY
BRING A FEW SHOWERS TO MAINLY THE PANHANDLE FRIDAY IN ASSOCIATION
WITH THE PASSING OF THE SHORT WAVE...THOUGH BETTER ENERGY SHOULD
PASS TO THE EAST OF THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1140 AM MDT SAT SEP 5 2015
A FEW LIGHT SHOWERS OR SPRINKLES MAY DEVELOP OVER THE AREA THIS
AFTERNOON...BUT THIS ACTIVITY WILL BE FEW AND FAR BETWEEN.
OUTSIDE ANY SHOWERS...WIND SPEEDS WILL GENERALLY BE LESS THAN
15KTS EAST OF THE LARAMIE RANGE THIS AFTERNOON. MEANWHILE...TAF
SITES SUCH AS LARAMIE AND RAWLINS WILL HAVE GUSTY SOUTHWEST WINDS
TODAY AT SPEEDS OF 20 TO 30 MPH WITH SOME GUSTS UP TO 35 MPH
POSSIBLE AS THE UPPER LEVEL DISTURBANCE IN THE NORTHWEST U.S. BEGINS
TO SHIFT NORTHEAST.
COX
&&
.FIRE WEATHER...
ISSUED AT 300 AM MDT SAT SEP 5 2015
MOIST SOUTHWEST FLOW ALOFT WILL PRODUCE SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS TO MOST OF THE FORECAST AREA THIS AFTERNOON
AND EVENING. THERE IS A LOW RISK OF DRY LIGHTNING. CRITICAL FIRE
WEATHER CONDITIONS WILL DEVELOP SUNDAY FOLLOWING THE PASSAGE OF A
COLD FRONT. WESTERLY WINDS WITH FREQUENT GUSTS OF 30 TO 40 MPH ARE
EXPECTED. DESPITE THE COOLER TEMPERATURES...RELATIVE HUMIDITIES
WILL FALL TO 10 TO 15 PERCENT SUNDAY AFTERNOON OVER PORTIONS OF
EAST AND SOUTH CENTRAL WYOMING.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...FIRE WEATHER WATCH FROM SUNDAY MORNING THROUGH SUNDAY EVENING
FOR WYZ301>303-308.
NE...NONE.
&&
$$
UPDATE...SML
SHORT TERM...MAJ
LONG TERM...RE
AVIATION...REC
FIRE WEATHER...MAJ
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
951 AM MDT SAT SEP 5 2015
.UPDATE...
ISSUED AT 951 AM MDT SAT SEP 5 2015
A FEW LIGHT SHOWERS AND SPRINKLES MOVING ACROSS NORTHERN PORTIONS
OF THE NEBRASKA PANHANDLE AT THIS TIME. THIS AREA OF SHOWERS WILL
QUICKLY MOVE OUT OF THE AREA BEFORE MORNINGS END BUT MORE SHOWER
ACTIVITY TO DEVELOP ACROSS THE FORECAST AREA THIS AFTERNOON.
UPDATED POP AND SKY COVER FORECAST TO REFLECT CURRENT CONDITIONS
AND TWEAKED CHANCES FOR SHOWERS AND THUNDERSTORMS THIS AFTERNOON.
BASED ON THE HRRR MODEL PERFORMANCE THE LAST FEW DAYS...ADDED
ISOLATED SHOWERS AND THUNDERSTORMS TO THE ENTIRE WESTERN NEBRAKSA
PANHANDLE THIS AFTERNOON.
ONCE AGAIN VERY LITTLE IN THE WAY OF MEASURABLE PRECIPITATION IS
EXPECTED. MAINLY LOOKING FOR A TRACE TO A FEW HUNDRETHS OF AN INCH
OF PRECIPITATION WITH LOCALLY HIGHER AMOUNTS WITH ANY THUNDERSTORM
ACTIVITY. THUNDERSTORMS WILL BE FEW AND FAR BETWEEN. INVERTED V
SOUNDINGS WILL ONCE AGAIN SUGGESTIVE OF GUSTY DOWNDRAFT/OUTFLOW
WINDS WITH SOME SHOWERS AND THUNDERSTORMS TODAY. GUSTS OF 40 TO 50
MPH LIKELY WITH SOME SHOWERS AND THUNDERSTORMS.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 303 AM MDT SAT SEP 5 2015
PREDAWN WATER VAPOR IMAGERY DEPICTED A UPPER TROUGH OVER THE
NORTHWEST CONUS WITH A LOW CENTERED OVER OR. A LARGE UPPER RIDGE
ENCOMPASSED THE EASTERN 2/3 OF THE NATION. SUBTROPICAL/MONSOON
MOISTURE CONTINUED TO STREAM NORTHEAST FROM BAJA CA INTO THE
ROCKIES AND HIGH PLAINS. A PASSING WEAK SHORT WAVE OVER FAR
SOUTHEAST WY AND WESTERN NE PRODUCED SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS. THIS ACTIVITY WILL END BY DAYBREAK. SKIES
WERE MOSTLY CLOUDY WITH LIGHT WINDS AND TEMPERATURES IN THE 50S
AND 60S.
THE SHORT RANGE MODELS HAVE MAINTAINED THEIR RUN-TO-RUN CONSISTENCY
FOR SEVERAL DAYS PROGGING THE PACIFIC NORTHWEST UPPER LOW TO LIFT
NORTHEAST THROUGH ID AND MT DURING THE NEXT 24 HOURS. THE MOIST
SOUTHWEST FLOW ALOFT WILL PROVIDE CHANCES FOR SHOWERS AND ISOLATED
THUNDERSTORMS FROM LATE THIS MORNING THROUGH THE AFTERNOON AND
EVENING...ESPECIALLY WEST OF I-25. GUSTY WINDS UP TO 45 MPH...
LIGHTNING AND BRIEF MODERATE TO HEAVY RAIN WILL BE THE PRIMARY
HAZARDS. OUTSIDE OF THE CONVECTION...SOUTHWEST WINDS WILL GUST TO
35 MPH WEST OF THE LARAMIE RANGE. IT WILL BE ANOTHER WARM AFTERNOON
FOR THE PLAINS WITH HIGHS IN THE 80S TO AROUND 90.
A PACIFIC COLD FRONT IS FORECAST TO MOVE EAST ACROSS THE CWA LATE
TONIGHT AND EARLY SUNDAY MORNING...USHERING IN A DRIER AND MORE
STABLE AIR MASS. WEST TO NORTHWEST WINDS WILL INCREASE TO 25 TO
35 MPH BEHIND THE FRONT SUNDAY MORNING...WITH HIGHER GUSTS
POSSIBLE IN WIND PRONE AREAS OF SOUTHEAST WY. SUNDAY WILL BE 5 TO
10 DEGREES COOLER WITH HIGHS IN THE 70S TO LOWER 80S.
MONDAY WILL BE A PLEASANT DAY WITH NEAR SEASONABLE TEMPERATURES. A
WEAK SURFACE TROUGH IS PROGGED BY MOST OF THE MODELS TO SET UP NEAR
THE WY-NE BORDER MONDAY WITH A FEW SHOWERS OR THUNDERSTORMS POSSIBLE
OVER THE FAR SOUTHEAST PART OF THE CWA...ROUGHLY EAST OF A ALLIANCE
TO SIDNEY LINE. BREEZY WEST WINDS WILL DEVELOP ALONG AND WEST OF
THE LARAMIE RANGE MONDAY AFTERNOON.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 300 AM MDT SAT SEP 5 2015
A LOW AMPLITUDE CYCLONIC UPPER FLOW SHOULD EXIST OVER SRN CANADA
AND THE NORTHERN TIER STATES MOST OF NEXT WEEK. SEVERAL UPPER
SHORT WAVES WILL TRANSLATE EAST ACROSS THE REGION IN THIS FLOW
PATTERN BRINGING SURGES OF COOLER AIR. ONE MINOR FRONT WILL SCOOT
ACROSS MONDAY NIGHT BUT HAVE LITTLE EFFECT ON THE SENSIBLE WEATHER
ACROSS THE CWA WITH WARM AND DRY WEATHER EXPECTED FOR TUESDAY AND
WEDS. A LITTLE STRONGER FRONT LOOKS TO PASS ACROSS LATER WEDS BUT
AGAIN LOOKS DRY. MILD TEMPS THURSDAY THEN A STRONGER SHORTWAVE
WILL MOVE SOUTHEAST OUT OF SOUTHERN CANADA INTO THE PLAINS THURSDAY
NIGHT DRIVING YET ANOTHER PUSH OF COOLER AIR SOUTH OUT OF CANADA
AND REINFORCING THE MILD AIR MASS OVER THE REGION. THIS SYSTEM MAY
BRING A FEW SHOWERS TO MAINLY THE PANHANDLE FRIDAY IN ASSOCIATION
WITH THE PASSING OF THE SHORT WAVE...THOUGH BETTER ENERGY SHOULD
PASS TO THE EAST OF THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 300 AM MDT SAT SEP 5 2015
VFR EXPECTED OVER ALL TERMINALS THROUGH THE PERIOD. ISOLATED
SHOWERS AND TSTMS SHOULD DEVELOP OVER PARTS OF THE AREA THIS
AFTERNOON THEN DISSIPATE THIS EVENING. SURFACE COLD FRONT WILL
PASS ACROSS THE AREA LATER TONIGHT.
&&
.FIRE WEATHER...
ISSUED AT 300 AM MDT SAT SEP 5 2015
MOIST SOUTHWEST FLOW ALOFT WILL PRODUCE SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS TO MOST OF THE FORECAST AREA THIS AFTERNOON
AND EVENING. THERE IS A LOW RISK OF DRY LIGHTNING. CRITICAL FIRE
WEATHER CONDITIONS WILL DEVELOP SUNDAY FOLLOWING THE PASSAGE OF A
COLD FRONT. WESTERLY WINDS WITH FREQUENT GUSTS OF 30 TO 40 MPH ARE
EXPECTED. DESPITE THE COOLER TEMPERATURES...RELATIVE HUMIDITIES
WILL FALL TO 10 TO 15 PERCENT SUNDAY AFTERNOON OVER PORTIONS OF
EAST AND SOUTH CENTRAL WYOMING.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...FIRE WEATHER WATCH FROM SUNDAY MORNING THROUGH SUNDAY EVENING
FOR WYZ301>303-308.
NE...NONE.
&&
$$
UPDATE...SML
SHORT TERM...MAJ
LONG TERM...RE
AVIATION...RE
FIRE WEATHER...MAJ
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1042 PM MDT SUN SEP 6 2015
.UPDATE...
ISSUED AT 1042 PM MDT SUN SEP 6 2015
UPPER JET MAX IS INTERACTING WITH MOISTURE AND INSTABILITY ON TOP
OF THE EML AND ISOLATED SHOWERS/THUNDER HAVE BEEN POPPING OVER THE
NORTHEAST UTAH. HRRR HAS THE BEST HANDLE LATE THIS PM SO WILL RELY
ON IT FOR GUIDANCE OVERNIGHT. POPS CHANGED AS A RESULT.
&&
.SHORT TERM...(TONIGHT THROUGH MONDAY NIGHT)
ISSUED AT 237 PM MDT SUN SEP 6 2015
ISOLATED SHOWERS AND THUNDERSTORMS HAVE FORMED ACROSS HIGHER
TERRAIN AND WITH AVAILABLE MOISTURE STARTING TO DROP...DO NOT
EXPECT COVERAGE TO INCREASE TOO MUCH THIS AFTERNOON. DEWPOINTS ARE
ABOUT 5 DEGREES LOWER THAN YESTERDAY AND THIS DRYING TREND WILL
CONTINUE AS FLOW BECOMES MORE WESTERLY. FOR MOST AREAS
THEN...EXPECT SOME CUMULUS BUILDUP...MAYBE A PASSING SHOWER FOR
THE HIGHER TERRAIN WITH AN OCCASIONAL RUMBLE OF THUNDER AND
SEASONAL TEMPS. MODELS PICKING UP ON A WEAK SHORTWAVE MOVING OVER
THE CWA NEAR 3AM KICKING OFF SOME SHOWERS BUT NOT SOLD ON IDEA SO
KEPT ANY MENTION OF PRECIP OUT OF FORECAST. LATER SHIFTS CAN
REEVALUATE AS NEEDED.
WHILE MONDAY WILL REMAIN PREDOMINANTLY DRY...ENOUGH MOISTURE WILL
LINGER FOR A FEW LATE DAY SHOWERS AND THUNDERSTORMS OVER THE
HIGHER TERRAIN. THE UPPER JET WILL WEAKEN THROUGH THE DAY...AND
GENERALLY WILL NOT PROVIDE MUCH SUPPORT TO THE AFTERNOON
CONVECTION. TEMPERATURES WILL REMAIN NEAR NORMAL FOR EARLY
SEPTEMBER...AT MOST A COUPLE DEGREES WARMER THAN TODAY.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 237 PM MDT SUN SEP 6 2015
A SHORTWAVE WILL PASS TO OUR NORTH ON TUE...WITH LITTLE IMPACT ON
OUR FORECAST AREA. MODELS INDICATE THAT CONVECTIVE ACTIVITY WILL
SHIFT TO THE SOUTH AS DRIER AIR MOVES OVER THE NORTH. THE SAN
JUANS SHOULD SEE A LITTLE BETTER COVERAGE THAN ON MONDAY. BUT
OTHER AREAS WILL EITHER SEE LITTLE CHANGE OR WILL BE DRIER.
BY WED THE SUBTROPICAL RIDGE WILL HAVE SHIFTED WESTWARD...INTO
THE DESERT SOUTHWEST AND ALONG THE WEST COAST. THIS PUTS OUR
FORECAST AREA UNDER A DRIER NORTHWEST FLOW. THE RIDGE WILL
CONTINUE TO BUILD OVER THE WEST COAST THROUGH THE WORK WEEK...THEN
REMAIN PARKED THERE THROUGH NEXT WEEKEND. THEREFORE LITTLE CHANCE
OF SHOWERS AND THUNDERSTORMS WILL BE EXPECTED THROUGH THE
REMAINDER OF THE FORECAST PERIOD. TEMPERATURES WILL WARM TO AROUND
5 DEGREES ABOVE NORMAL FOR THE SECOND HALF OF THE WEEK. NIGHTTIME
LOWS WILL HOVER AROUND NORMAL IN THE DRY AIR MASS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1042 PM MDT SUN SEP 6 2015
VFR CONDITIONS PREVAIL THE NEXT 24 HOURS AT AREA FORECAST
TERMINALS. ISOLATED -SHRA/-TSRA CAN BE EXPECTED IN THE VICINITY OF
KVEL/KGJT/KRIL THROUGH SUNRISE...THEN KASE/KEGE/KTEX WILL HAVE A
SMALL CHANCE THIS AFTERNOON. OVERALL CONFIDENCE...OUTSIDE OF KVEL
THROUGH 07Z...IS LOW AND FORECASTS WILL CONVEY THIS. WILL HAVE TO
WATCH USUAL UPVALLEY/NORTHWEST WINDS AT KASE FOR LANDING ISSUES
THIS AFTERNOON AS WELL.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
UPDATE...15
SHORT TERM...TGR/EH
LONG TERM...EH
AVIATION...TGJT
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
322 AM EDT MON SEP 7 2015
.SYNOPSIS...
AN UPPER LOW OVER THE FORECAST AREA WILL SHIFT SOUTHWESTWARD
THROUGH TODAY WITH A COOL AND MOIST FLOW OFF THE ATLANTIC. AN
UPPER RIDGE WILL BUILD OVER THE AREA BY MID WEEK BRINGING WARMING
TEMPERATURES. A COLD FRONT AND UPPER TROUGH WILL BRING UNSETTLED
WEATHER FOR THE END OF THE WEEK.
&&
.NEAR TERM /TODAY AND TONIGHT/...
SURFACE ANALYSIS SHOWS AN AREA OF HIGH PRESSURE CENTERED OVER NEW
ENGLAND CONTINUING TO RIDGE DOWN THE EAST COAST INTO THE
CAROLINAS. MEANWHILE AN UPPER AREA OF LOW PRESSURE IS MOVING
WESTWARD THROUGH THE SOUTHEAST.
LATEST RADAR LOOP SHOWING SCATTERED SHOWERS BEING CONFINED MAINLY TO
THE IMMEDIATE COAST. GFS INDICATING WEAK COASTAL SURFACE TROUGH
MOVING ONSHORE LATER TODAY. SPC HRRR INDICATING SCATTERED CONVECTION
PUSHING INTO THE AREA FROM THE COAST LATER THIS AFTERNOON. CHANCE
POPS LOOK REASONABLE FOR THE AFTERNOON. PRECIPITABLE WATER VALUES
GENERALLY AT OR ABOVE 2.0 INCHES SO LOCALLY HEAVY RAIN POSSIBLE.
CONVECTION SHOULD WEAKEN DURING THE EVENING HOURS WITH LOSS OF
DAYTIME HEATING. AFTERNOON HIGHS MOSTLY IN THE MIDDLE 80S WITH
OVERNIGHT LOWS EARLY TUESDAY MORNING AROUND 70.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/...
CLOSED UPPER LOW CENTERED ALONG THE GULF COAST STATES WILL CONTINUE
TO SLOWLY RETROGRADE AND FILL...WHILE WEAK UPPER RIDGING EXPANDS
OVER THE SOUTHEASTERN STATES FROM THE WESTERN ATLANTIC. THE SURFACE
PATTERN IS WEAK WITH HIGH PRESSURE CENTERED OVER VIRGINIA WEAKENING
WHILE A PERSISTENT SOUTHEASTERLY FLOW CONTINUES TO USHER MOISTURE
INLAND OFF THE ATLANTIC. PRECIPITABLE WATER VALUES WILL GRADUALLY
INCREASE TO AROUND 2 INCHES BY TUESDAY AFTERNOON AND REMAIN HIGH
THROUGH WEDNESDAY AS SOUTHERLY WINDS DEVELOP THROUGH THE LOWEST
20KFT OF THE ATMOSPHERE IN RESPONSE TO A TROUGH MOVING THROUGH THE
UPPER MISSISSIPPI AND OHIO VALLEYS.
WILL CONTINUE TO ADVERTISE HIGH CHANCE POPS ACROSS MUCH OF THE
REGION ON TUESDAY WITH THE HIGHEST POPS ACROSS THE SOUTHERN HALF OF
THE FORECAST AREA. THE THREAT OF SEVERE WEATHER APPEARS LOW WITH
PREDOMINATELY MOIST PROFILES AND WEAK SHEAR BUT HEAVY RAIN MAY BE A
CONCERN WITH STRONGER AND SLOW MOVING STORMS. SCATTERED UNORGANIZED
CONVECTION AGAIN EXPECTED ON WEDNESDAY WITH CONTINUED ELEVATED
MOISTURE PROFILES AND SLIGHTLY BETTER INSTABILITY. TEMPERATURES ON
TUESDAY AND WEDNESDAY WILL BE WARMER THAN THE PREVIOUS COUPLE OF
DAYS AND EXPECT HIGHS TO PUSH BACK INTO THE LOWER 90S WITH LOWS IN
THE LOWER 70S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
THE EXTENDED FORECAST FEATURES WHAT LOOKS LIKE AN ACTIVE WEATHER
REGIME WITH A MEAN TROUGH SETTING UP ACROSS THE EASTERN HALF OF THE
COUNTRY. AN INITIAL UPPER TROUGH WILL PUSH INTO THE REGION FROM THE
NORTHWEST ON THURSDAY RESULTING IN HEIGHT FALLS WHILE A SURFACE
TROUGH DEVELOPS OVER THE FORECAST AREA. THE SHORTWAVE TROUGH IS
FORECAST TO TRAVERSE THE FORECAST AREA THURSDAY NIGHT INTO FRIDAY
AND PUSH OFFSHORE BY FRIDAY NIGHT AS A COLD FRONT PUSHES INTO THE
AREA AND STALLS. THE FRONT WILL REMAIN STATIONARY OVER THE REGION
SATURDAY PROVIDING A FOCUS FOR PRECIPITATION AS SOUTHWESTERLY FLOW
ALOFT INCREASES IN ADVANCE OF ANOTHER SHORTWAVE TROUGH DIGGING
ACROSS THE OHIO VALLEY. THIS TROUGH WILL PUSH YET ANOTHER FRONT
INTO THE REGION BY EARLY SUNDAY AS A 1020MB SURFACE RIDGE SETTLES
ACROSS THE OHIO VALLEY INTO THE MID ATLANTIC STATES BY SUNDAY NIGHT.
WILL CONTINUE MENTION OF SOLID CHANCE POPS THURSDAY AND FRIDAY WITH
THE FOCUS OF HIGHER POPS SHIFTING TO THE SOUTHEASTERN PART OF THE
AREA ON SATURDAY AND SUNDAY. TEMPERATURES DURING THIS PERIOD WILL
GENERALLY BE ABOVE NORMAL EARLY IN THE PERIOD AND NEAR NORMAL OVER
THE WEEKEND.
&&
.AVIATION /07Z MONDAY THROUGH FRIDAY/...
MVFR TO POSSIBLY IFR CIGS COULD REDEVELOP AS A STRATUS DECK DEVELOPS
ACROSS THE REGION. A 20 TO 25 KNOT LOW LEVEL JET SHOULD RESULT IN
MAINLY STRATUS OVER FOG. MODELS SHOW IMPROVEMENT AROUND MID-DAY TO
EARLY AFTERNOON WHICH ALIGNS WELL WITH THE PERSISTENCE FORECAST.
ANOTHER CHANCE FOR CONVECTION LATER THIS AFTERNOON WITH THE BEST
CHANCE SOUTH AND EAST. WILL MENTION VCSH MAINLY FOR THE AFTERNOON
AND EARLY EVENING HOURS. WINDS WILL GENERALLY BE OUT OF THE
NORTHEAST THROUGH THE PERIOD AT 10 KNOTS OR LESS.
EXTENDED AVIATION OUTLOOK...LATE NIGHT/MORNING FOG/STRATUS
POSSIBLE...WITH A CHANCE OF AFTERNOON SHOWERS AND POSSIBLE
THUNDERSTORMS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1222 AM CDT MON SEP 7 2015
.SHORT TERM /TONIGHT/...
ISSUED AT 305 PM CDT SUN SEP 6 2015
STILL SOME UNCERTAINTY ABOUT EVOLUTION OF SYSTEM TONIGHT. VARIOUS
MODEL SOLUTIONS BEGINNING TO EITHER POINT TOWARD SLIGHTLY MORE
PROGRESSIVE EVOLUTION OF CONVECTION OVERNIGHT...OR SLIGHTLY MORE
NORTH PLACEMENT OF MAX.
SO FAR CONVECTIVE TRENDS HAVE BEEN RAMPING UP SLOWLY DUE TO H700
TEMPS SITTING ABOVE 11-12C THIS AFTERNOON. BUT AS FRONT ENTERS
NW/W IA EARLY THIS EVENING AND AREA BECOMES UNCAPPED AND H700
TEMPS COOL A COUPLE OF DEGREES...A RAPID INCREASE IN STORMS SHOULD
OCCUR BETWEEN 4 PM AND 7 PM. DESPITE THE EXPECTED MODEL
UNCERTAINTY...WE ARE IN NEAR RECORD TERRITORY FOR AVAILABLE
ATMOSPHERIC MOISTURE FOR EARLY SEPTEMBER. THIS IS DUE IN PART TO A
PROLONGED FETCH OF GULF MOISTURE WHICH IS FEEDING NORTHEAST INTO
THE CENTRAL PLAINS AND GREAT LAKES. SECONDLY...A TROPICAL
CONNECTION FROM THE SOUTHWEST US THAT RESULTED IN AN OLD TROPICAL
SYSTEM EARLIER IN THE WEEK OFF THE COAST OF BAJA MEXICO BEING
INGESTED IN THE MID TO UPPER LEVEL FLOW. PWAT VALUES WILL BE
APPROACHING 2 TO 2.25 INCHES BETWEEN 00-06Z TONIGHT PLACING OUR
VALUES IN THE 99TH/100TH PERCENTILE AND OVER 3 SDEV ABOVE NORMAL
FOR THIS TIME OF YEAR. WARM CLOUD DEPTHS ARE NEAR 14.5KFT WHICH IS
EXTREMELY DEEP. THERE REMAIN NUMEROUS FACTORS SUPPORTING
EFFICIENT/HIGH RAINFALL RATES THIS EVENING...AND LOOKING
AHEAD...AGAIN MONDAY NIGHT. BACK TO THE MODELS...CONSECUTIVE RUNS
OF THE HRRR ARE SHOWING A MORE PROGRESSIVE EVOLUTION TO TONIGHTS
CONVECTION WITH FORWARD PROPAGATING CORFIDI VECTORS ABOUT 20 KTS.
BUT EVEN THIS IS DECEIVING IF RAINFALL RATES ARE 2-3 INCHES PER
HOUR AT TIMES...AND STILL SUGGESTS A QUICK COUPLE OF INCHES OF
RAIN IN THE MORE VIGOROUS CELLS. WITH ANY LOCALIZED
TRAINING...STILL A POTENTIAL FOR ISOLATED 3 TO 4 INCHES AMOUNTS
OVERNIGHT. THE NAM IS LEANING TOWARD THE MORE PROGRESSIVE HRRR
OVERNIGHT WITH THE GFS RAMPING UP CONVECTION BETWEEN 00-06Z ON THE
NOSE OF THE INCREASING LOW LEVEL JET ALONG THE INVERTED TROUGH
WITHIN THE ZONE OF MAXIMUM SFC CONVERGENCE. THE QPF MAX IS
CENTERED OVER HIGHWAY 30...ROUGHLY BETWEEN US 20/I80 FROM GREENE
TO MARSHALL COUNTIES. WITH THAT ADDED UNCERTAINTY TONIGHT AND THE
POSSIBLE NORTHERLY SHIFT BY 20 MILES OF THE QPF MAX...WILL BE
ADDING ONE ROW OF COUNTIES TO TONIGHTS FFA ALONG US 20. REALIGNING
THE WATCH NOW IS RISKY...DUE TO THE POSSIBILITY OF THE MODELS ARE
NOT PROPERLY ACCOUNTING FOR A STRONGER OUTFLOW BOUNDARY LATER IN
THE EVENING...WHICH WOULD THEN BE FEEDING OFF AN INCREASING LOW
LEVEL JET OVERNIGHT. THERE MAY ACTUALLY BE TWO FAVORED AREAS OF
HEAVY RAINFALL...EARLIER BETWEEN US20/30 AND LATER ALONG AND SOUTH
OF I80. NONE THE LESS...THE RISK FOR FLASH FLOODING AND SUBSEQUENT
ISSUES REMAINS. TIMING OF THE EVENT SUGGESTS THAT STORMS SHOULD BE
IN FULL SWING BETWEEN 02-09Z WITH ACTIVITY REMAINING STRONG BUT
SLOWLY DIMINISHING BETWEEN 09-13Z MONDAY OVER THE SOUTH/SOUTHEAST.
LOWS TONIGHT WILL FALL TO THE LOWER 70S SOUTH TO NEAR 60 OVER THE
FAR NORTHWEST AS THE COOLER AIR BEGINS TO FILTER INTO THE REGION
TONIGHT. TONIGHTS RAINFALL WILL PRIME THE REGION FOR A MORE
SIGNIFICANT RISK OF FLOODING MONDAY NIGHT AND THIS IS COVERED IN
THE EXTENDED DISCUSSION.
.LONG TERM /MONDAY THROUGH SUNDAY/...
ISSUED AT 305 PM CDT SUN SEP 6 2015
A POTENTIALLY SIGNIFICANT HEAVY RAIN AND FLOODING EVENT MAY BE
SHAPING UP EARLY THIS WEEK.
THE COLD FRONT SAGGING DOWN INTO IOWA TONIGHT...AS DISCUSSED IN
THE SHORT TERM SECTION ABOVE...WILL LIKELY STALL ACROSS SOUTHERN
IOWA BY MONDAY MORNING THEN RETREAT BACK NORTHWARD A BIT TOWARD
CENTRAL IOWA DURING THE DAY. DESTABILIZATION WILL BE LIMITED BY
DEBRIS CLOUDS AND A LACK OF LOW LEVEL WARM AIR ADVECTION OVER
MOST OF THE FORECAST AREA...PLUS THERE WILL BE NO LARGE SCALE
FORCING MECHANISM FOR CONVECTION FOR MOST OF THE DAY. NEVERTHELESS
THE AIRMASS WILL BE JUICED ENOUGH WITH THE BOUNDARY WOBBLING
AROUND THAT LOW POPS ARE MAINTAINED ON MONDAY.
BEGINNING LATE MONDAY AFTERNOON AND ESPECIALLY ON MONDAY NIGHT THE
ATMOSPHERE APPEARS TO BE SETTING UP FOR A SIGNIFICANT...POSSIBLY
EXTREME HEAVY RAINFALL EVENT. ALONG AND SOUTH OF THE NEARLY
STATIONARY FRONTAL ZONE PWAT VALUES WILL BE NEAR RECORDS WITH
SUBSTANTIAL MOISTURE TRANSPORT CONTINUING FROM THE GULF ESPECIALLY
AS THE NOCTURNAL LOW LEVEL JET KICKS IN AFTER DARK.
CONCURRENTLY...A SECOND FAIRLY ROBUST MID LEVEL SHORTWAVE WILL
ROUND THE BASE OF BROAD CYCLONIC FLOW ALOFT AND PROVIDE A TRIGGER
FOR WIDESPREAD THUNDERSTORM DEVELOPMENT. WITH WARM CLOUD DEPTHS IN
EXCESS OF 15 KFT IN FORECAST SOUNDINGS AND THE COMBINATION OF
OTHER FACTORS...WE WILL BE PRIMED FOR VERY EFFICIENT RAINFALL
RATES AND POTENTIALLY TRAINING OR SLOW MOVING STORMS NEAR THE
FRONTAL ZONE. THIS COULD LEAD TO WIDESPREAD RAINFALL AMOUNTS IN
THE 2 TO 3 INCH RANGE WITHIN A BROAD SWATH ACROSS THE AREA...AND
LOCALIZED AMOUNTS OF 6 INCHES OR MORE ARE DEFINITELY CONCEIVABLE.
IN TERMS OF THE FLOODING EFFECTS OF SUCH RAINFALL...MUCH WILL
DEPEND ON WHERE IT FALLS AND WHETHER IT OCCURS IN THE SAME AREA AS
THE HEAVIEST RAINFALL TONIGHT...WHICH IS IN TURN DEPENDENT ON THE
DIFFICULT TO PREDICT MOTIONS AND LOCATION OF THE FRONTAL BOUNDARY
BY MONDAY EVENING. IT IS LIKELY...IN ANY EVENT...THAT A SECOND
FLASH FLOOD WATCH WILL BE NEEDED AFTER TONIGHTS RAINFALL PANS
OUT...AND THAT IT MAY NEED TO HAVE EVEN STRONGER WORDING FOR THE
POTENTIAL EFFECTS MONDAY NIGHT INTO TUESDAY MORNING.
SCATTERED THUNDERSTORMS MAY CONTINUE TO FESTER ACROSS OUR SOUTHERN
COUNTIES ON TUESDAY AS THE FRONTAL ZONE LINGERS NEAR THE
IOWA/MISSOURI BORDER...BUT THEN ANOTHER SHORTWAVE TROUGH WILL MOVE
OVERHEAD AROUND TUESDAY EVENING AND FINALLY CLEAR OUT THE WET
AIRMASS TO OUR SOUTH. THIS WILL BRING AN END OF ANY HEAVY RAIN
THREAT FOR THE REMAINDER OF THE SEVEN DAY FORECAST...ALONG WITH
NOTABLY COOLER AND DRIER WEATHER ACROSS IOWA. THERE WILL BE A
CHANCE FOR SCATTERED SHOWERS AND STORMS AROUND THURSDAY AS A
REINFORCING COLD FRONT SURGES ACROSS THE STATE...USHERING IN THE
FIRST TRULY AUTUMNAL WEATHER OF THE SEASON AT THE END OF THIS WEEK
WITH FRIDAY HIGHS IN THE 60S AND FRIDAY NIGHT LOWS IN THE 40S
STATEWIDE.
&&
.AVIATION...07/06Z
ISSUED AT 1222 AM CDT MON SEP 7 2015
SOME STORMS TO STILL IMPACT KOTM KDSM AND KALO THROUGH THE
OVERNIGHT HOURS...WITH FOG CHANCES AT THE NORTHERN SITES LOOKING
SOMEWHAT UNCERTAIN. WINDS TO SHIFT AROUND TO THE SOUTHEAST TO
SOUTH AGAIN LATE IN THE FORECAST PERIOD...WITH ANOTHER ROUND OF
STORMS POSSIBLE BEGINNING LATE MONDAY AFTERNOON INTO MONDAY NIGHT.
CIGS TO BE IN THE MVFR TO LOW VFR RANGE...BUT MAY DIP INTO IFR IF
FOG DEVELOPS.
&&
.HYDROLOGY...
ISSUED AT 305 PM CDT SUN SEP 6 2015
AS REFERENCED IN THE PREVIOUS DISCUSSIONS...TWO HEAVY
RAINFALL EVENTS ARE POSSIBLE TONIGHT THROUGH TUESDAY MORNING WITH
THE FOCUS FROM NORTH CENTRAL TO SOUTHERN IOWA. WIDESPREAD RAINFALL
AMOUNTS OF 2 TO 3 INCHES ARE EXPECTED WITH AMOUNTS EXCEEDING 5
INCHES POSSIBLE DURING THIS PERIOD. MONDAY NIGHTS EVENT IS STILL
EXPECTED TO BE OF GREATER MAGNITUDE...SO SOME REEVALUATION OF THE
WATCH OUTLINE WILL OCCUR BETWEEN THIS EVENING AND TOMORROW
MORNING AFTER TONIGHTS RAINFALL REPORTS ARE GATHERED. IN BOTH
EVENTS...EFFICIENT RAIN PRODUCING STORMS WILL PRODUCE HEAVY
RAINFALL OVER A SHORT PERIOD OF TIME. SIGNIFICANT RUNOFF AND/OR
PONDING OF WATER IS LIKELY IN SOME AREAS LEADING TO A FLASH FLOOD
THREAT. THE EVENT MAY EVOLVE INTO A RIVER FLOODING THREAT THROUGH
MID TO LATE WEEK AS THE RUNOFF REACHES THE LARGER STREAMS. THE
MAGNITUDE OF RIVER FLOODING ON ANY GIVEN MAINSTEM RIVER WILL
DEPEND ON BOTH RAINFALL AMOUNTS AND BASIN COVERAGE IN THE NEXT 48
TO 60 HOURS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 10 AM CDT THIS MORNING FOR ADAIR-ADAMS-
APPANOOSE-AUDUBON-BOONE-CASS-CLARKE-DALLAS-DAVIS-DECATUR-GREENE-
GUTHRIE-JASPER-LUCAS-MADISON-MAHASKA-MARION-MARSHALL-MONROE-POLK-
POWESHIEK-RINGGOLD-STORY-TAMA-TAYLOR-UNION-WAPELLO-WARREN-WAYNE.
&&
$$
SHORT TERM...REV
LONG TERM...LEE
AVIATION...BEERENDS
HYDROLOGY...REV
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1155 PM CDT SUN SEP 6 2015
...Update to aviation forecast discussion...
.UPDATE...
ISSUED AT 933 PM CDT SUN SEP 6 2015
Convective development in the local forecast area continues to
struggle, but a rather strong model signal continues to indicate
that elevated storms (similar to that currently seen in far
southeast Nebraska) will develop into eastern KS as well tonight.
It seems that for this to occur depends on the development of a
cold pool from the ongoing storms. This currently exists near the
Nebraska border, and if it can continue to be reinforced and
pushed south than would expect at least scattered storms to
develop overnight. If this happens, the severe weather threat is
quite low but non-zero for wind/hail. Pockets of heavy rain also
remain possible if these storms develop as there could be
localized training, but dry ground conditions suggest the flash
flood potential is quite low.
&&
.SHORT TERM...(THIS EVENING THROUGH Monday)
ISSUED AT 254 PM CDT SUN SEP 6 2015
Latest surface analysis had the frontal boundary from just east of
Albion Nebraska to near Norton Kansas at 19Z. Surface temperatures
ahead of the front across northeast Kansas have warmed to near the
century mark in north central and northeast Kansas. Latest
mesoanalysis along with latest RAP soundings show steep low level
lapse rates and SBCAPE around 3000 J/kg this afternoon. Hires
short term models have differing scenarios with regards to
convective development, with the operational HRRR and the RAP the
most robust with developing storms where the ARW, NMM and
experimental HRRR showing less coverage across central and north
central Kansas tonight. However most models continue to show a
signal of a MCS developing across far northeast Kansas into
southwest Iowa and northwest Missouri tonight and then moving it
south southeast across eastern Kansas and western Missouri. The
aforementioned frontal boundary will gradually move eastward
tonight into the forecast area. Not sure exactly how far south the
boundary will move tonight before lifting north again on Labor
Day. Water vapor loop this afternoon shows moisture streaming from
the eastern Pacific into the Central Plains. Southwesterly low
level jet will advect high theta-e air into northeast Kansas
overnight and should help to maintain the forward propagating MCS
as well as contribute to high precipitation efficiency. On Labor
day the front is expected to lift northward in response to an
upper level trough moving eastward into the Northern and Central
Plains to near or just north of the Nebraska and Kansas border in
the afternoon. Left over boundaries from morning convection may
focus isolated convection in the afternoon, but feel most areas
will be dry until late afternoon along the Kansas and Nebraska
border near the front. Effective shear tonight and Labor Day will
be around 25 to 30 kts along with ample instability. If storms
develop late this afternoon and early evening they will have the
potential for damaging wind gusts and also again on Labor Day
afternoon. There is also some potential for Hail as storms become
elevated later tonight, but locally heavy rainfall will be the
main concern. Lows tonight remain mild in the low to mid 70s and
highs on Labor Day will be dependent on cloud cover. Feel there
may be enough sunshine to send temps back into the lower 90s for
most areas.
.LONG TERM...(Monday NIGHT THROUGH Sunday)
ISSUED AT 254 PM CDT SUN SEP 6 2015
Monday night through Wednesday...Synoptic scale boundary should
extend from southeast Nebraska through north central KS by early
Monday evening. As boundary sags slowly south over night, expect
clusters of thunderstorms to develop along it and move east, with
the best chance for heavier rainfall north of I70, and especially
near and north of U.S. 36. Have highest POPs and most QPF for that
area. On Tuesday, most short term models bring frontal boundary
nearly through the forecast area, although outflow from
thunderstorm complex makes it somewhat hard to place. Highest POPs
should shift from northeast KS into far eastern, and especially
east central KS during the afternoon. Thunderstorm activity near
the front should shift out of east central KS during the evening.
Would expect late Tuesday night and Wednesday to be dry as a ridge
of surface high pressure builds in.
Wednesday night through Sunday...Eastern KS remains in northwest
flow aloft through Saturday. While gulf airmass should remain to
our south, periodic disturbances in this northwest flow will
result in chances for showers and thunderstorms. Cooler, more
stable airmass over far northeast KS is expected to keep the
best chance for convective activity over north central and parts
of east central KS. Much cooler temperatures than we`ve had
recently are expected for the latter part of the week into the
weekend, with highs in the 70s to lower 80s, depending on how much
sun is seen each afternoon.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z Monday NIGHT)
ISSUED AT 1152 PM CDT SUN SEP 6 2015
Another rather uncertain TAF concerning convective potential. Have
maintained periods of VCTS to highlight the most likely timing of
TS near TAF sites, but have not gone with prevailing TS as
coverage is not likely to be widespread and confidence in
development is on the lower end. Outside of thunderstorms, VFR
conditions are likely through the TAF period.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Barjenbruch
SHORT TERM...53
LONG TERM...GDP
AVIATION...Barjenbruch
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1257 AM EDT MON SEP 7 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 327 PM EDT SUN SEP 6 2015
A SHORTWAVE THAT MOVED THROUGH LAST NIGHT INTO THIS MORNING PRODUCED
HEAVY RAIN OVER WRN LAKE SUPERIOR AND MN...AND EVEN BROUGHT SHOWERS
AND THUNDERSTORMS TO FAR WRN UPPER MI AND ERN LAKE SUPERIOR. OVER
MOST LAND AREAS...AN EML WAS TOO STRONG TO ALLOW CONVECTION TO
CONDITIONS...WITH ONLY A FEW DROPS HAVING FALLEN AT WFO MQT TODAY AS
A ROGUE SHOWER PASSED BY. CLOUD COVER HAS BEEN MORE EXTENSIVE DUE TO
THE MORNING CONVECTION...AS WELL AS CONVECTION UPSTREAM OVER WI THAT
HAS SENT HIGH CLOUDS OVER MUCH OF THE AREA. THIS HAS BROUGHT DOWN
MAX TEMPS A FEW DEGREES FROM WHAT WAS PREVIOUSLY EXPECTED.
STILL...MUGGY CONDITIONS PERSIST AS LOW-MID 80S TEMPS AND LOW 70S
DEW POINTS ARE BEING OBSERVED.
MODELS HAVE NOT PERFORMED WELL ALL DAY...EVEN THE HRRR HAS CONTINUED
TO INITIALIZE WITH HEAVY PRECIP OVER WRN UPPER MI WHERE NON EXISTS.
THIS SEEMS LIKELY DUE TO AN UNDERESTIMATION OF BOTH THE STRENGTH OF
THE EML/CIN AND POOR HANDLING OF MORNING PRECIP/CLOUD COVER. LATEST
RUNS OVER MANY HIGH-RES MODELS ARE NOW DOING A DECENT JOB WITH QPF
OVER THE CWA AT THE PRESENT...BUT ARE VERY POOR IN THEIR HANDLING OF
UPSTREAM CONVECTION OVER NERN MN (ASSOCIATED WITH A COLD FRONT
MOVING SE) AND CONVECTION OVER WRN WI AND SOUTH MN AHEAD OF A
SHORTWAVE AND WEAK SFC LOW NEAR THE MN/SD BORDER. THE HRRR IS
HANDLING UPSTREAM CONVECTION WELL...AND IT ALSO IS SIMILAR TO THE
OTHER MODELS BY TIME THE NEXT ROUND OF CONVECTION MOVES IN MAINLY
AFTER 00Z THIS EVENING. THIS LENDS GREATER CONFIDENCE TO OTHER
MODELS...SO WILL USE THEN SINCE THEY ALSO ARE DOING WELL NOW. MAIN
MODELS USED ARE THE NAM...NAM DNG...REGIONAL GEM...NCEP HIGH-RES WRF
ARW AND NMM. SHOWERS AND THUNDERSTORMS WILL MOVE IN AFTER 00Z THIS
EVENING AS THE SHORTWAVE EJECTS INTO THE AREA AND THE SFC LOW MOVES
THROUGH THE N...DRIVING THE COLD FRONT THROUGH. HEAVY RAIN IS
EXPECTED IN ANY THUNDERSTORMS DUE TO WELL ABOVE NORMAL
MOISTURE/PWATS. OTHER THREATS ARE POSSIBLY LARGE HAIL AND DAMAGING
WINDS...MAINLY OVER THE W. MUCAPES OF 1000-1500J/KG (MAINLY THIS
HIGH OVER THE W) AND 0-6KM BULK SHEAR AROUND 30 ARE MARGINAL
VALUES...SO SOME STRONG TO SEVERE STORMS ARE POSSIBLE OVER THE
W...BUT NOT LIKELY.
STILL SOME UNCERTAINTY MON. MODELS GENERALLY AGREE THAT MOST OF THE
PRECIP WILL BE E OF THE CWA BY 18Z...EXCEPT MAYBE A COUPLE NUISANCE
SHOWERS OVER THE E. HOWEVER...THE NAM AND NCEP HIGH-RES WRF NMM ARE
SHOWING CONVECTION BREAKING OUT IN THE AFTERNOON OVER ERN UPPER MI.
HOWEVER...DID NOT INCORPORATE THAT INTO THE FORECAST AT THIS TIME AS
THOSE MODELS SEEM TO BE OVERDOING SFC TEMPS AND INSTABILITY. SKIES
SHOULD CLEARING FROM THE W...LAGGING THE LONGEST OVER THE E NEAR
LAKE SUPERIOR. HIGHS SHOULD BE IN THE 70S TO AROUND 80...WARMEST FAR
SOUTH CENTRAL.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 449 PM EDT SUN SEP 6 2015
MONDAY NIGHT THROUGH TUESDAY...THE GFS AND ECMWF WERE IN RELATIVELY
GOOD AGREEMENT WITH THE STRENGTH/POSITION OF THE SHORTWAVE MOVING
OUT OF THE PLAINS TOWARD THE GREAT LAKES THAT SUPPORTS DEVELOPMENT
OF A SFC WAVE ALONG THE FRONT. WITH MOST OF THE PCPN TO THE SOUTH OF
THE CWA...CHANCE POPS WERE MAINTAINED FOR THE SE HALF...ESPECIALLY
ALONG LAKE MICHIGAN.
TUE NIGHT INTO WED...HIGH PRES WILL BUILD INTO THE WRN LAKES TUE
NIGHT INTO WED WITH CLEARING SKIES. LOOK FOR TEMPS NEAR SEASONAL
AVERAGES WITH LOWS AROUND 50 TO 55 AND HIGHS AROUND 70.
THU-FRI...THE GFS/GEFS/ECMWF REMAIN IN RELATIVELY GOOD AGREEMENT
WITH THE SHORTWAVE TROUGH DIGGING TOWARD THE UPPER MS VALLEY WED
NIGHT AND THROUGH THE NRN LAKES THU. ELEVATED INSTABILITY MAY BE
MARGINAL FOR TSRA...BUT WITH MODERATE TO STRONG DEEP LAYER QVECTOR
CONV AND FAVORABLE MOISTURE TRANSPORT...AT LEAST ISOLD TS WILL BE
POSSIBLE. THE 12Z ECMWF HAS TRENDED BACK TOWARD A DEEPER TROUGH INTO
THE GREAT LAKES BY FRI WITH DEEP MOISTURE AND NRLY CYCLONIC FLOW
THAT WOULD SUPPORT SHOWERS AND LAKE ENHANCED RAIN INTO UPPER MI.
EVEN THOUGH GFS IS MORE PROGRESSIVE AND NOT AS DEEP WITH THE
TROUGH...850 MB TEMPS TO AROUND 2C (LAKE TEMPS AROUND 15C) MAY STILL
BE COLD ENOUGH TO PRODUCE SOME LAKE EFFECT PCPN. MORE FALL-LIKE
CONDITIONS ARE EXPECTED WITH HIGHS ONLY IN THE UPPER 50S AND LOWER
60S FRI.
SAT-SUN...ALTHOUGH A TRANSITION BACK TOWARD A MORE ZONAL PATTERN IS
EXPECTED WITH MODERATING TEMPS SAT...THERE IS UNCERTAINTY WITH THE
AMOUNT OF HEIGHT FALLS INTO THE NRN CONUS ASSOCIATED WITH A
SHORTWAVE MOVING TOWARD HUDSON BAY OR NW ONTARIO. THE 12Z/6
ECMWF...UNLIKE THE DRY GFS AND 00Z/6 ECMWF DROPS A SHORTWAVE AND
FRONT WITH PCPN INTO THE NRN LAKES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1257 AM EDT MON SEP 7 2015
SHRA/TSRA...SOME WITH VERY HEAVY RAINFALL...WILL CONTINUE TO SPREAD
E ACROSS THE AREA OVERNIGHT IN ASSOCIATION WITH A COLD FRONT.
PRECIPITION WILL BE ENDING AT KIWD/KCMX IN THE NEXT FEW HRS...WHILE
HEAVIER PCPN WILL AFFECT KSAW FOR THE NEXT COUPLE OF HRS. EXPECT
IFR/LIFR CONDITIONS TO DEVELOP AT KIWD/KCMX DURING THE NIGHT...WITH
KSAW FALLING TO LIFR AROUND SUNRISE. IMPROVEMENT TO VFR WILL OCCUR
FROM W TO E AT ALL TERMINALS FROM LATE MORNING THRU MID AFTN AS
DRIER AIR ARRIVES BEHIND COLD FRONT.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 327 PM EDT SUN SEP 6 2015
FOG WILL REMAIN A CONCERN UNTIL THE FRONTAL PASSAGE LATE TONIGHT AS
HIGH DEW POINTS KEEP MOVING ACROSS THE COLDER WATER. SOUTH WINDS
TODAY WILL TURN WESTERLY ON MONDAY THEN DECREASE MON NIGHT INTO TUE.
OVERALL...NEXT WEEK LOOKS FAIRLY QUIET ON THE LAKE WITH NO MAJOR
SYSTEMS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...TITUS
LONG TERM...JLB
AVIATION...ROLFSON
MARINE...TITUS
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
1120 PM MDT SUN SEP 6 2015
AVIATION SECTION UPDATED.
.DISCUSSION...
UPDATE FORTHCOMING. MODELS, INCLUDING HRRR AND RAP13,
ALL BEING SOME LIGHT PRECIPITATION OFF THE ROCKY MOUNTAIN FRONT AND
OUT OVER THE PLAINS AFTER 06Z AS WEAK SHORT WAVE ENERGY MOVES
THROUGH. HAVE ADDED LOW POPS FOR AFOREMENTIONED AREA FOR THIS
REASON. REMAINDER OF FORECAST LOOKS GOOD AS DO OVERNIGHT LOWS.
&&
.AVIATION...
UPDATED 2320Z.
WESTERLY FLOW ALOFT WILL CONTINUE TO BRING MID AND HIGH CLOUDS
ACROSS THE AREA. WINDS HAVE DROPPED TO LIGHT AND VARIABLE AT MOST
TERMINALS TONIGHT...BUT WEST WIND GUSTS TO AROUND 25KTS WILL
REDEVELOP MONDAY. VFR CONDITIONS PREVAIL.
&&
.PREV DISCUSSION...ISSUED 241 PM MDT SUN SEP 6 2015
TONIGHT THROUGH TUESDAY...GUSTY WESTERLY WINDS AFFECTING THE
FORECAST AREA THIS AFTERNOON WILL DIMINISH DURING THE EARLY TO MID
EVENING HOURS. WEST TO NORTHWEST CYCLONICALLY-CURVED FLOW ALOFT
WILL PREVAIL FOR MONDAY AND TUESDAY WITH AFTERNOON HIGH
TEMPERATURES REMAINING BELOW SEASONAL AVERAGES. SEVERAL SHORTWAVES
MOVING THROUGH THE FLOW ALOFT WILL BRING SCATTERED SHOWERS TO THE
MOUNTAINS OF THE CONTINENTAL DIVIDE AND GLACIER PARK, BUT ONLY
ISOLATED LIGHT RAIN SHOWERS ARE EXPECTED IN THE PLAINS AND
VALLEYS. WINDS REMAIN WESTERLY AND BREEZY BUT ARE NOT EXPECTED TO
BE AS STRONG AS THOSE OF TODAY. MPJ
TUESDAY NIGHT THROUGH SUNDAY...LITTLE IF ANY SIGNIFICANT WEATHER
EXPECTED DURING THIS PERIOD. ONLY WEATHER SYSTEM OF NOTE IS A
QUICK- MOVING SHORTWAVE TROF THAT WILL PRODUCE SOME SCATTERED
LIGHT RAIN SHOWERS THROUGH CENTRAL MT THROUGH TUES NIGHT. ALSO,
RESIDUAL MOISTURE FROM THIS SYSTEM MAY COMBINE WITH NORTHWEST FLOW
ALOFT TO GENERATE A FEW SHOWERS AND A THUNDERSTORM OR TWO OVER THE
LITTLE BELT AND SNOWY MTNS ON WED AFTN/EVE WHILE REST OF REGION
REMAINS DRY. FROM LATE WED ONWARD, HIGH PRESSURE RIDGING WILL
SLOWLY BUILD INTO THE NORTHERN ROCKIES, MAINTAINING THE DRY
CONDITIONS THROUGH AT LEAST SATURDAY. LATEST FORECAST MODEL RUNS
SHOW THE NORTHERN PORTION OF THE RIDGE WEAKENING ON SUNDAY IN
RESPONSE TO AN UPPER- LEVEL TROF MOVING THROUGH WESTERN CANADA.
HOWEVER, ONLY LIMITED MOISTURE MAKES IT SOUTH OF THE US/CAN
BORDER, PERHAPS ENOUGH TO DEVELOP A FEW SHOWERS ALONG THE ROCKY
MTN FRONT, BUT DOWNSLOPE FLOW SHOULD KEEP PRECIPITATION FROM
FORMING OVER THE PLAINS. AS THE RIDGE MOVES INTO OUR REGION, WE`LL
SEE A GRADUALLY WARMING TREND WITH LOW 70S ON THURS INCREASING TO
THE LOW 80S FOR SAT. 12Z FORECAST MODELS INDICATE THE POTENTIAL
FOR A DISTURBANCE WITH AN ASSOCIATED COLD FRONT TO MOVE THROUGH
THE FORECAST AREA ON SUNDAY, BUT THERE IS SOME DISCREPANCY WITH
REGARDS TO STRENGTH. HAVE THEREFORE ADDED MENTION OF SHOWERS AND
HAVE COOLED SUNDAY`S HIGHS AROUND 5 DEGREES TO ACCOUNT FOR THIS.
WARANAUSKAS/COULSTON
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 43 62 42 67 / 10 10 10 10
CTB 40 60 42 64 / 10 20 10 10
HLN 42 64 40 68 / 10 10 20 0
BZN 37 63 36 70 / 0 0 20 0
WEY 23 59 23 62 / 0 0 10 0
DLN 35 62 35 69 / 0 0 10 0
HVR 39 62 41 67 / 10 10 10 10
LWT 41 60 39 68 / 10 10 10 0
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
WEATHER.GOV/GREATFALLS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
426 AM CDT MON SEP 7 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 AM CDT MON SEP 7 2015
MOSTLY CLEAR SKIES ARE BEING OBSERVED ACROSS THE LOCAL AREA THIS
MORNING...ALBEIT SOME LOW LEVEL STRATUS HAS BEGUN TO DEVELOP IN
SPOTS. WHILE THIS STRATUS IS PATCHY AT THE MOMENT...EXPECT THIS
STRATUS TO CONTINUE TO SPREAD IN COVERAGE THROUGH DAY BREAK...WITH
SOME LOCALLY DENSE FOG ALSO POSSIBLE THROUGH THE EARLY MORNING
HOURS. THUS FAR...FOG HAS NOT BEEN ABLE TO DEVELOP...BUT WITH DEW
POINT DEPRESSIONS CONTINUING TO SHRINK AND A FEW TEMPS NOW
REACHING THEIR ASSOCIATED DEWPOINT VALUES...CONTINUE TO THINK THE
LATEST HRRR MIGHT BE CORRECT WITH AT LEAST SOME PATCHY DENSE FOG
DEVELOPING AROUND SUNRISE. AS A RESULT...CONTINUED TO MAINTAIN THE
LOWER VISIBILITY WORDING FOR THE MORNING HOURS OF THE FORECAST
AND WILL ALSO CONTINUE TO ADVERTISE IN THE HWO.
WITH SOME CONVECTION ALREADY FORMING ACROSS THE HIGH PLAINS...AND
FAVORABLE UPPER LEVEL JET DYNAMICS EXPECT BY MID
AFTERNOON...EXPECT SOME SHOWERS AND THUNDERSTORMS TO DEVELOP AND
MOVE ACROSS THE REGION...GENERALLY FAVORING AREAS ACROSS SOUTH
CENTRAL NEBRASKA. MODEL SOUNDINGS ARE INDICATIVE OF AMPLE CAPE
ACROSS THE REGION...AND THIS INSTABILITY COMBINED WITH 0-6KM SHEAR
VALUES UPWARDS OF 50KTS EXPECTED LATER IN THE DAY...WOULD NOT BE
SURPRISED TO SEE A FEW STRONG AND ORGANIZED THUNDERSTORMS DEVELOP
ACROSS THE LOCAL AREA. LATEST CONVECTIVE OUTLOOK FROM SPC IS
INDICATIVE OF THIS...WITH THE ENTIRE AREA RIGHT IN THE MIDDLE OF A
MARGINAL RISK FOR SEVERE WEATHER THIS AFTERNOON. AS WITH
YESTERDAY...WHILE THE OVERALL TORNADO THREAT IS FAIRLY LOW...A 2
PERCENT TORNADO RISK IS IN THE LATEST OUTLOOK...AND WILL ADD THIS
MENTION TO THE HWO DESPITE LARGE HAIL AND THUNDERSTORM WIND GUSTS
BEING THE PRIMARY CONCERNS.
TEMPERATURE WISE...EXPECT MOST AREAS TO STRUGGLE TO REACH OR
SLIGHLY EXCEED 80 DEGREES THIS AFTERNOON...WHICH WILL BE A NICE
CHANCE FOR MOST FOLKS. ONCE SKIES CLEAR AND RAINFALL CHANCES
DIMINISH SOME OVERNIGHT...EXPECT A SEASONABLY COOL START TO
TUESDAY FOR THE LOCAL AREA...WITH NEAR TO SLIGHTLY ABOVE SEASONAL
NORMS FOR LOW TEMPERATURES...WITH FORECAST LOWS GENERALLY FALLING
INTO THE UPPER 50S ACROSS OUR NORTH...AND INTO THE LOWER TO MIDDLE
60S ACROSS NORTH CENTRAL KANSAS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 405 AM CDT MON SEP 7 2015
PRIMARY FORECAST CONCERN THROUGH THE LONG TERM LIES WITH
PRECIPITATION CHANCES.
THE START OF THE PERIOD SHOWS MODELS NOT IN TOO BAD OF AGREEMENT
WITH THE OVERALL UPPER LEVEL PATTERN...WITH THE CWA UNDER ZONAL TO
SLIGHTLY SWRLY FLOW...THANKS TO BROAD TROUGHING CONNECTED TO A LOW
PRESSURE SYSTEM LOCATED OVER NORTH CENTRAL CANADA. AT THE
SFC...STILL EXPECTING THERE TO BE A FRONTAL BOUNDARY MEANDERING
AROUND THE AREA...THOUGH EXACT PLACEMENT IS UNCERTAIN AS IT WILL
LIKELY BE AFFECTED BY ANY THUNDERSTORMS MOVING THROUGH TONIGHT.
CONTINUE TO HAVE POPS RIGHT OFF THE BAT TUESDAY MORNING...LINGERING
ACTIVITY FROM TONIGHT...WHICH IS EXPECTED TO BE SLIDING OFF TO THE
EAST WITH A GRADUALLY VEERING/WANING LLJ. THINKING IS THAT THERE
WILL BE AT LEAST A BIT OF A BREAK IN ACTIVITY LATER IN THE MORNING
PERHAPS INTO THE EARLY AFTERNOON HOURS...BUT ANOTHER LOBE OF
SHORTWAVE ENERGY ASSOCIATED WITH THAT UPPER LEVEL CANADIAN LOW IS
EXPECTED TO MOVE INTO THE AREA FROM THE NW LATE IN THE
AFTERNOON...PROVIDING THE OPPORTUNITY FOR ADDITIONAL THUNDERSTORMS.
WHILE KEPT POPS IN PLACE CWA-WIDE DURING THE AFTERNOON...HAVE 30-40
POPS GOING ACROSS THE SERN PORTIONS OF THE CWA...CLOSER TO THE MAIN
SFC FRONT WHICH LOOKS TO EXTEND FROM EAST CENTRAL TO SOUTH CENTRAL
PORTIONS OF KS BY TUES EVENING. HAVE SOME LINGERING 20 POPS DURING
THE EVENING HOURS...BUT KEPT THE FORECAST DRY POST-06Z AS THINGS GET
PUSHED FURTHER S/SE. CONFIDENCE IN TEMPS FOR TUESDAY IS NOT
HIGH...AND WILL BE GREATLY AFFECTED BY LINGERING PRECIP/CLOUDS AS
WELL AS THE ULTIMATE LOCATION OF THE SFC BOUNDARY. AT THIS
POINT...HIGHS ARE FORECAST TO REACH THE UPPER 70S TO LOWER 80S.
THE FORECAST FOR WED IS A DRY ONE...WITH THE TUES SYSTEM EXPECTED TO
PUSH OFF TO THE EAST...LEAVING MORE NWRLY /BUT STILL LOW AMPLITUDE/
UPPER LEVEL FLOW IN ITS WAKE. A WEAK SFC PATTERN AND LIGHT WINDS TO
START THE DAY IS EXPECTED TO GIVE WAY TO MORE SOUTHERLY WINDS WITH
TIME...AS SFC LOW PRESSURE BECOMES BETTER ORGANIZED TO OUR WEST
AHEAD OF THE NEXT UPPER LEVEL SYSTEM APPROACHING THE REGION FROM THE
NW. THE LACK OF A NOTABLE CHANGE IN AIR MASS BEHIND THE EARLY WEEK
FRONT LOOKS TO KEEP HIGH TEMPS FOR WED IN THE UPPER 70S/LOWER 80S.
LOOKING AT THE WED NIGHT THROUGH EARLY SAT PERIOD...CONFIDENCE IN
THE FORECAST IS NOT HIGH...AS PLENTY OF DIFFERENCES BETWEEN MODELS
REMAIN. THE LATEST RUN OF THE GFS SHOWS THE POSSIBILITY OF A COUPLE
OF SHORTWAVE DISTURBANCES MOVING THROUGH DURING THIS TIME
FRAME...WHILE THE ECMWF SHOWS A MORE ORGANIZED CLOSED LOW DEVELOPING
BY THURS EVENING OVER THE WRN GREAT LAKES AND PUSHING OFF TO THE
EAST. ONE OF THE RESULTING DIFFERENCES IS THE GFS WOULD BRING A
COUPLE OF SHOTS AT PRECIP...VS THE LIKELY JUST ONE SHOT VIA THE
ECMWF. HAD INHERITED A FEW PERIODS OF POPS IN THIS TIME FRAME...AND
WITH THE GFS STILL SUPPORTING THAT WILL KEEP IT GOING...BUT IF
THINGS TREND TOWARD THE 00Z ECMWF...SOME OF THOSE PERIOD WOULD NEED
TO HAVE POPS REMOVED. WE SHALL SEE. BOTH SOLUTIONS SHOW ANOTHER SFC
COLD FRONT MOVING THROUGH THE REGION...WITH THE ECMWF SHOWING A
BETTER PUSH OF COOLER AIR THAN THE GFS AT THIS POINT. FORECAST HIGHS
REMAIN A BLEND THURS-SAT...DROPPING BACK INTO THE 70S CWA-WIDE.
BETTER AGREEMENT KEEPING SUN DRY...WITH HIGHS REBOUNDING BACK INTO
THE 80S FOR MAINLY THE SWRN THIRD OR SO OF THE CWA.
&&
.AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1243 AM CDT MON SEP 7 2015
CLEARING SKIES EARLY THIS MORNING COMBINED WITH ELEVATED
DEWPOINTS AND LIGHT NORTHEASTERLY WINDS...WILL RESULT IN THE
FORMATION OF AT LEAST IFR CIGS/VSBYS TOWARDS 07/10Z. THIS FOG IS
EXPECTED TO LINGER FOR SEVERAL HOURS...BEFORE CONDITIONS IMPROVE
AFT 07/15Z...OR THEREABOUTS. OTHERWISE...EXPECT THE PRESENCE OF AN
OLD FRONTAL BOUNDARY NEAR THE SURFACE AND UPPER LEVEL DISTURBANCE TO
PROVIDE THE FOCUS FOR AFTERNOON SHOWER AND THUNDERSTORM
DEVELOPMENT...AND OPTED TO INTRODUCE THE CHANCE FOR A VCTS DURING
THE LATE AFTERNOON THROUGH EVENING HOURS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...ROSSI
LONG TERM...ADP
AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
400 AM CDT MON SEP 7 2015
.SYNOPSIS...
ISSUED AT 356 AM CDT MON SEP 7 2015
LARGE UPPER LOW LOCATED OVER SRN CANADA WITH TROUGH AXIS SWD INTO
MT AND ID...WITH NOTABLE PV ANOMALY MOVING THROUGH THE BASE OF
THE TROUGH OVER NRN NV. ZONE OF HIGHER SWRLY FLOW ALOFT LOCATED
AHEAD OF THIS UPPER TROUGH FROM MN TO SRN CA...RUNNING THROUGH
THE NWRN CORNER OF NEB. ALONG THIS SWRLY FLOW ALOFT...WEAK SHORT
WAVES CONTINUE TO PROGRESS QUICKLY NEWD AS THEY HAVE THE PAST FEW
DAYS. SFC FRONT THAT MOVED THROUGH THE AREA THIS MORNING LOCATED
FROM SRN IA ACROSS NERN KS SWWD TO NEAR DDC. THIS FRONT MARKED BY
CONVECTION FROM SRN IA INTO NERN KS. ON THE NORTH SIDE OF THIS
FRONT...ERLY UPSLOPE FLOW EXISTS AT THE SFC WITH NERLY WIND AT
500M/1KM AT KLNX. SFC WINDS HAVE TURNED SERLY ALREADY FROM THE
PANHANDLE INTO NWRN KS AND THIS IS CONTRIBUTING TO TSRA
DEVELOPMENT ACROSS WRN NEB. VSBYS STARTING TO BE REDUCED IN THE
ONL AREA DUE TO FOG.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 356 AM CDT MON SEP 7 2015
FOR THIS MORNING...TSRA DEVELOPING AND MOVING EWD ALONG GRADIENT
OF STEEPER LAPSE RATES ALOFT AND WILL LIKELY BE SUSTAINED AS
ELEVATED INSTABILITY EXPANDS EWD IN INCREASING ISENTROPIC
UPGLIDE. CIRA LOW CLOUD/FOG PRODUCT SHOWING ONLY LIMITED
DEVELOPMENT OF LOW CLOUDS AS EXPECTED BY SHORT RANGE MODELS AND
SREF PROBABILITY GUIDANCE. WILL CONTINUE THE IDEA OF PATCHY FOG
THOUGH CONVECTIVE TRENDS SO FAR WOULD SUGGEST FURTHER FOG
DEVELOPMENT MAY BE INHIBITED SOMEWHAT.
PREVIOUSLY MENTIONED PV ANOMALY OVER NRN NV WILL CONTINUE TO
ROTATE NEWD TODAY AND AS THE ENTIRE TROUGH PULLS EWD...UPPER
LEVEL JET DEVELOPMENT OCCURS IN CONFLUENT ZONE OVER WY TODAY.
THIS WILL PUT THE RIGHT ENTRANCE REGION OF THE NEWLY DEVELOP JET
STREAK OVER WRN NEB BY AFTERNOON. THE RESULTING DIRECT THERMAL
CIRCULATION THAT IS ALREADY DEVELOPING IN RESPONSE OVER THE HIGH
PLAINS...AS EVIDENCED BY ISENTROPIC LIFT ON THE 310/315K
SFC...WILL INDUCE A NWRLY LOW LEVEL AGEOSTROPHIC FLOW AND ENHANCE
FRONTOGENSIS ACROSS THE WRN PORTION OF THE AREA THIS AFTERNOON.
AS THIS OCCURS IN A REGION OF DECENT MID LEVEL INSTABILITY...NEW
TSRA SHOULD DEVELOP THIS AFTERNOON IN WRN NEB AND MOVE EWD. CAPE
IS NOT EXTREME BUT WITH GOOD SHEAR IN PLACE THROUGH A DEEP LAYER
SOME POTENTIAL FOR LARGE HAIL WILL EXIST WITH ANY STORMS THAT DO
DEVELOP...HENCE THE MARGINAL RISK AS DEPICTED BY SPC. THE FLY IN
THE OINTMENT HERE WOULD BE ONGOING CONVECTION AND CONVECTIVE
DEBRIS THAT REMAIN FROM THIS MORNINGS CONVECTION AND HOW THAT
AFFECTS THE ATMOSPHERE BY THIS AFTERNOON. CLOUD COVER MAY
NEGATIVELY AFFECT THE STORMS BEING ABLE TO REALIZE AVAILABLE
CAPE...BUT LEFT OVER BOUNDARIES MAY BE A FOCUS FOR UPWARD
VERTICAL MOTION ENHANCEMENT TO POSITIVELY INFLUENCE INDIVIDUAL
UPDRAFTS...SO ANOTHER COMPLICATED FCST REMAINS. SHORT RANGE
MODELS AND CAM ENSEMBLES AGAIN SUGGEST A WIDE RANGE OF POSSIBLE
SOLUTIONS. ALTHOUGH THE HRRR HAS HAD ITS STRUGGLES LATELY...THINK
IT MIGHT BE ON TO THE RIGHT IDEA DEVELOPING TSRA IN THE 3-4PM CDT
TIME RANGE. THIS IDEA IS ALSO SUPPORTED BY THE NSSL WRF AND BY A
FEW MEMBERS OF THE NCAR 10 MEMBER 3KM WRF ENSEMBLE. THE POPS FCST
IS THEREFORE LIMITED TO THE CHC RANGE FOR NOW.
FOG/LOW CLOUDS MAY BE POSSIBLE AGAIN TONIGHT AND IS SHOWN IN SOME
OF THE MOS GUIDANCE AS WELL AS THE 07.03Z SREF. ULTIMATE
DEVELOPMENT HOWEVER WILL DEPEND ON THE CONVECTIVE TRENDS
OVERNIGHT...SO CONFIDENCE WAS NOT HIGH ENOUGH TO INCLUDE IN THE
FCST AT THIS POINT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 356 AM CDT MON SEP 7 2015
CHILLY TUESDAY WITH LINGERING MORNING SHOWERS GIVING WAY TO
PARTLY SUNNY SKIES. COOL HIGH PRESSURE BUILDS ACROSS THE AREA AND
BATTLE BETWEEN CAA AND SEPTEMBER SUN. THE BIGGEST THING TO WATCH
IS HOW SOON CLOUDS DISSIPATE...WHICH WILL HAVE A DIRECT IMPACT ON
HIGHS. MOST AREAS HOLD IN THE 70S...EXCEPT FOR FAR SW WITH HIGHS
AROUND 80...ALTHOUGH AN EARLIER CLEARING WILL BUMP UP TEMPS A
GOOD 5 DEGREES OR MORE.
BL MOISTURE WILL BE A CONCERN TUESDAY NIGHT INTO WED MORN. THE
NAM WHICH HAS MORE BL MOISTURE SUGGESTS STRATUS/FOG COULD DEVELOP
WITH WINDS BECOMING SOUTHEASTERLY/SOUTHERLY ON THE BACK SIDE OF
THE SFC HIGH. THE GFS/EC MOS GUIDANCE IS DRIER AND KEEPS THINGS
CLEAR AND HAS SLIGHTLY LOWER TEMPS. MODELS HAVE BEEN STRUGGLING
WITH LOW LEVEL MOISTURE...WHICH LEADS TO LOW CONFIDENCE IN
WHETHER FOG/STRATUS WILL DEVELOP OR NOT.
WEDNESDAY WILL SEE THE NEXT WEAK COLD FRONT PUSH ACROSS THE AREA.
SLIGHT WARM UP AHEAD OF THE FRONT WITH MOST HIGHS AROUND 80 INTO
THE MID 80S. MODELS HAVE BEEN IN GOOD AGREEMENT DEVELOPING A LINE
OF STORMS ALONG THE BOUNDARY WHICH MODEL BLENDS PLACE ACROSS THE
HEART /FROM NORTHEAST TO SOUTHWEST/ OF THE CWA DURING PEAK
HEAT/INITIATION. SHEAR IS WEAK HOWEVER A NARROW BAND WITH CAPE
VALUES OF 500 TO 1000 J/KG SO EXPECT AT LEAST SOME ISOLD THUNDER.
HIGH PRESSURE BRINGS DRY AIR FOR THURSDAY. HIGH QUICKLY MOVES
EAST FOR FRIDAY WITH RETURN SOUTHERLY FLOW TO BRING AN INCREASE
OF MOISTURE. SOME AFTERNOON INSTABILITY DEVELOPS THEN A LL JET
KICKS IN OVERNIGHT. RESULTS IN AT LEAST A SLGHT CHANCE FOR
PRECIP FRIDAY INTO FRIDAY NIGHT. INBETWEEN SYSTEMS FOR THE
WEEKEND WITH SEASONAL AND DRY CONDITIONS EXPECTED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1144 PM CDT SUN SEP 6 2015
THE POTENTIAL FOR FOG/STRATUS IS THE FIRST AVIATION CONCERN
TONIGHT AND EARLY MONDAY. EAST TO NORTHEAST WIND WILL BRING MORE
MOISTURE UP THE PLATTE RIVER VALLEY POSSIBLY AS FAR WEST AS OGA
BUT LIKELY TO REACH LBF. WE HAVE SOME CONFIDENCE THAT INSTRUMENT
METEOROLOGICAL CONDITIONS WILL REACH LBF AND BBW BUT ONLY WEAK
CONFIDENCE THAT IT WILL REACH ANY FARTHER WEST. IF IT IS STRATUS
THAT COMES IN...THE CEILING IS LIKELY TO BE LESS THAN 1000 FEET
WHILE...IF STRATUS DOES NOT COME...VISIBILITY IS LIKELY TO BE
LESS THAN 3SM.
SHORT TERM OUTPUT FROM ONLY TWO OF THE FIVE MODEL CYCLES GIVES
SOME WEAK INSTABILITY AHEAD OF A WEAK UPPER SYSTEM...SO THERE IS
A POSSIBILITY OF SHOWERS OR THUNDERSTORMS EARLY MONDAY.
HOWEVER...THE DIFFERENCES IN THE MODEL OUTPUT PARES OUR
CONFIDENCE TO LESS THAN THIRTY PERCENT THAT THIS WILL OCCUR.
LOOKING A LITTLE FARTHER OUT...IT IS POSSIBLE THAT SOME STRONG
THUNDERSTORMS WILL DEVELOP LATE AFTERNOON OR EARLY EVENING THOUGH
THERE IS CONSIDERABLE UNCERTAINTY WITH THE TIMING AND THE
LOCATION. CONSIDERING THE MODEL OUTPUT STATISTICS...ONE BULLETIN
INDICATES 20-40 PERCENT PROBABILITY BOTH MONDAY MORNING AND
MONDAY EVENING FOR BBW AND LBF AND THE OTHER GIVES THE 20-40
PERCENT PROBABILITY TO THE EVENING ONLY. THUS THE RESULT IS
THAT...IF I WERE TO PICK THE TIMING...I WOULD FOCUS ON THE
EVENING AFTER 23Z.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JWS
SHORT TERM...JWS
LONG TERM...MASEK
AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1258 AM CDT MON SEP 7 2015
.UPDATE...
ISSUED AT 1243 AM CDT MON SEP 7 2015
WINDS ARE SHIFTING EARLY THIS MORNING AND BECOMING MORE
NORTHEASTERLY...HELPING TO ADVECT IN HIGHER DEWPOINTS FROM THE
NORTHEAST. THIS MORE HUMID AIR...COMBINED WITH CLEARING SKIES AND
FALLING TEMPERATURES...SHOULD ALLOW FOR THE FORMATION OF AT LEAST
AREAS OF FOG DURING THE EARLY MORNING HOURS. LATEST/04Z RUN OF
THE HRRR INDICATES WE COULD SEE WIDESPREAD DENSE FOG AROUND
SUNRISE...BUT OPTED TO ONLY UPDATE FORECAST TO INDICATE
VISIBILITIES FALLING TO 1 SM FOR THE TIME BEING...BUT WILL NEED
TO CONTINUE TO MONITOR IN CASE MORE DENSE FOG DOES INDEED FORM
OVERNIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 345 PM CDT SUN SEP 6 2015
ALOFT: THE PERSISTENT WRN USA TROF/ERN USA RIDGE WILL REMAIN THRU
TOMORROW...BUT DEAMPLIFICATION WAS UNDERWAY. THE DEEP WRN USA TROF
WILL BECOME MORE BROAD AS THE LOW THAT WAS STALLED OVER THE PAC NW
THIS PAST WEEK HEADS NE INTO CNTRL CANADA. QUIET SW FLOW WILL
REMAIN OVER THE CNTRL PLAINS. HOWEVER...THERE WERE A COUPLE WEAK
SHORTWAVE TROFS OVER WA AND NRN CA. AS THESE TROFS CROSS THE NRN
ROCKIES TONIGHT AND N OF THE FCST AREA TOMORROW...THIS WILL FORCE
THE UPR- LVL JET STREAK TO THE E PUTTING THE FCST AREA IN THE RRQ.
MASS ADJUSTMENT/LIFT SHOULD CREATE AN INCREASINGLY FAVORABLE
ENVIRONMENT FOR TSTMS MON AFTERNOON.
SURFACE: THE COOL FRONT THAT WAS QUASI-STATIONARY WELL NW OF THE
FCST AREA THIS PAST WEEK WAS NOW MOVING THRU. AS IT BECOMES
PARALLEL TO THE FLOW ALOFT...ITS FWD PROGRESS WILL SLOW AND IT
WILL BECOME QUASI-STATIONARY JUST S AND E OF THE FCST AREA
TONIGHT. SOME MODELS SUGGEST IT COULD LIFT BACK N INTO S-CNTRL NEB
TOMORROW...BUT THERE IS DISAGREEMENT ON THIS.
NOW THRU EARLY EVE: HOT S AND E OF THE TRI-CITIES. THE COOL FRONT
CURRENTLY EXTENDS FROM COLUMBUS-AURORA-SMITH CENTER-PLAINVILLE KS.
WE COULD SEE AN ISOLATED STORM OR TWO DEVELOP...PROBABLY SOMEWHERE
FROM GENEVA-YORK-BELOIT. CAN`T RULE OUT A SVR STORM WITH MLCAPE
2000-2500 J/KG...BUT EFFECTIVE SHEAR IS ONLY 25 KTS.
TONIGHT: ANY STORMS WILL EXIT EARLY...PROBABLY BY 6 OR 7 PM. WE
NEED TO WATCH DEVELOPMENT OF POST-FRONTAL STRATUS. OBS SHOW MVFR
CIGS OVER ERN SD AT 20Z. THE NAM 500M DWPT DEPRESSIONS SUGGEST
STRATUS FORMS AND SPREADS W ACROSS NEB TONIGHT. EC/GFS/NAM CROSS
SECTIONS ALL HAVE IT TO SOME EXTENT. SO EXPECT INCREASING CLOUDS.
EVEN IF STRATUS DOESN`T MATERIALIZE...EXPECT EXTENSIVE
CIRROSTRATUS/ALTOCU TO OVERTAKE THE AREA AFTER MIDNIGHT FROM THE
SW.
MON: MODELS ARE TRYING TO DEVELOP HIGH-BASED SHWRS/TSTMS OVER ERN
CO LATE TONIGHT...AND BRINGING THEIR REMNANTS E INTO THE FCST AREA
DURING THE MORNING. CONFIDENCE IS LOW ON THIS. IT COULD END UP
JUST MID-LVL SPRINKLES FROM ACCAS.
MODELS SUGGEST SCT TSTMS DEVELOP IN THE AFTERNOON AND THIS SEEMS
REASONABLE WITH THE JET DYNAMICS ACTING ON THE FRONT. CLOUD COVER
WILL BE A BIG PLAYER IN HOW TSTMS DEVELOP/EVOLVE. 15Z/SREF FCSTS
MLCAPE 3000-4000 J/KG...BUT THE SREF COULD BE 3-4F TOO HIGH WITH
ITS DWPTS. REGARDLESS...DEEP LAYER SHEAR OF 30-40 KTS WILL SUPPORT
ORGANIZED/SUSTAINED UPDRAFTS AND POTENTIAL FOR SVR TSTMS.
WITH BACKED WINDS N OF THE WARM FRONT...IF ANY STORMS CAN REMAIN
DISCRETE AND FORM ON OR JUST N OF THE FRONT AND/OR DEVELOP IN THE
WARM SECTOR AND CROSS THE FRONT...A TORNADO OR TWO WOULD BE
POSSIBLE.
SPC INDICATED IN THE SWODY2 THAT AN UPGRADE TO SLGT RISK MAY
BE NECESSARY. HAVE ALREADY INDICATED POTENT SVR IN THE HWO IN
ANTICIPATION OF THIS.
TEMPS A TOUGH CALL. THEY WILL DEPEND ON CLOUD COVER. IF STRATUS
REMAINS LOCKED BELOW THE FRONTAL INVERSION...SOME AREAS MAY NOT
GET OUT OF THE 70S. IT COULD REALLY HEAT UP AGAIN S OF THE FRONT.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 345 PM CDT SUN SEP 6 2015
GUIDANCE SUGGESTS A CLOSED UPPER TROPOSPHERIC LOW WILL EXIST OVER
WESTERN AND CENTRAL PORTIONS OF CANADA TO START THE LONG-TERM
FORECAST PERIOD AT 00Z TUESDAY...WITH AN ASSOCIATED TROUGH LIKELY
EXTENDING SOUTH/SOUTHWEST FROM THE LOW INTO PORTIONS OF THE
NORTHWESTERN CONUS. THIS UPPER TROPOSPHERIC LOW IS EXPECTED TO
MOVE EAST TUESDAY AND WEDNESDAY BEFORE BECOMING STATIONARY OVER
THE HUDSON BAY THURSDAY AND FRIDAY. THIS SHOULD ALLOW THE UPPER
TROPOSPHERIC TROUGH OVER THE NORTHWESTERN CONUS TO ALSO MOVE EAST
ACROSS THE NORTHERN PLAINS...AND PORTIONS OF THE CENTRAL
PLAINS...TUESDAY AND WEDNESDAY. AN UPPER TROPOSPHERIC SHORT
WAVE...MOVING SOUTHEAST ALONG THE BACKSIDE OF THE LOW...IS THEN
EXPECTED TO DIVE SOUTHEAST ACROSS THE NORTHERN AND CENTRAL PLAINS
ON THURSDAY...WITH YET ANOTHER SHORT WAVE EXPECTED TO DO THE SAME
ON FRIDAY. THIS PARADE OF SHORT WAVES SHOULD THEN CEASE SATURDAY
AND SUNDAY AS THE LOW OVER THE HUDSON BAY MOVES EAST/NORTHEAST AND
SUBTLE UPPER TROPOSPHERIC RIDGING OVERTAKES THE CENTRAL CONUS.
UPPER TROPOSPHERIC THERMAL ADVECTION AHEAD OF THE TROUGH ON
TUESDAY AND WEDNESDAY COULD BE SUFFICIENT FOR PRECIPITATION
PRODUCTION ACROSS MUCH OF OUR AREA MONDAY NIGHT INTO EARLY
WEDNESDAY...A SOLUTION SUPPORTED BY QPF FIELDS FROM THE
NAM...OPERATIONAL GFS AND EC. GIVEN THIS...POPS REMAIN INTACT
ACROSS MUCH OF THE CWA MONDAY NIGHT THROUGH VERY EARLY WEDNESDAY.
THE PASSAGE OF THE NEXT TWO SHORT WAVES WILL THEN PROMOTE
ADDITIONAL UPPER TROPOSPHERIC THERMAL ADVECTION AND RESULTANT
OMEGA THURSDAY AND FRIDAY...AND POPS REMAIN INTACT ACROSS MUCH OF
THE CWA ON BOTH OF THESE DAYS AS WELL. DRY CONDITIONS ARE THEN
FORECAST SATURDAY AND SUNDAY AS AN OVERALL LACK IN OMEGA OVERTAKES
THE AREA.
NEAR-NORMAL TEMPERATURE READINGS...WITH HIGHS NEAR 80 AND LOWS IN
THE MID TO UPPER 50S...ARE CURRENTLY EXPECTED DURING THE MIDDLE
PART OF NEXT WEEK...BUT THE INFILTRATION OF A MUCH COOLER AIR MASS
WILL LIKELY RESULT IN BELOW-NORMAL TEMPERATURE READINGS THURSDAY
AND BEYOND...WITH HIGHS GENERALLY IN THE 70S AND LOWS NEAR 50
EXPECTED.
&&
.AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1243 AM CDT MON SEP 7 2015
CLEARING SKIES EARLY THIS MORNING COMBINED WITH ELEVATED
DEWPOINTS AND LIGHT NORTHEASTERLY WINDS...WILL RESULT IN THE
FORMATION OF AT LEAST IFR CIGS/VSBYS TOWARDS 07/10Z. THIS FOG IS
EXPECTED TO LINGER FOR SEVERAL HOURS...BEFORE CONDITIONS IMPROVE
AFT 07/15Z...OR THEREABOUTS. OTHERWISE...EXPECT THE PRESENCE OF AN
OLD FRONTAL BOUNDARY NEAR THE SURFACE AND UPPER LEVEL DISTURBANCE TO
PROVIDE THE FOCUS FOR AFTERNOON SHOWER AND THUNDERSTORM
DEVELOPMENT...AND OPTED TO INTRODUCE THE CHANCE FOR A VCTS DURING
THE LATE AFTERNOON THROUGH EVENING HOURS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...ROSSI
SHORT TERM...HALBLAUB
LONG TERM...BRYANT
AVIATION...ROSSI
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1139 PM MDT SUN SEP 6 2015
.AVIATION...
06Z TAF CYCLE
SUBTROPICAL MOISTURE WILL SURGE NORTHWARD INTO NM OVERNIGHT INTO MONDAY.
EXPECT A SIGNIFICANT UPSWING IN SHOWER AND THUNDERSTORM ACTIVITY
BEGINNING LATE MORNING MONDAY AND CONTINUING THROUGH THE AFTERNOON
AND EVENING. NW PLATEAU INCLUDING KFMN THE LEAST LIKELY AREA TO
EXPERIENCE CONVECTION. MTS OCCASIONALLY OBSCD IN MVFR CIGS/VSBYS
WITH THE STRONGER STORMS MONDAY AFTERNOON/EVENING. SFC WND GUSTS
TO 40KT POSSIBLE WITH THE STRONGER STORMS.
33
&&
.PREV DISCUSSION...318 PM MDT SUN SEP 6 2015...
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS WILL CONTINUE TO FAVOR AREAS SOUTH OF
I-40 THIS EVENING...BUT STORMS MAY EXPAND FARTHER NORTHWARD ON
MONDAY AFTERNOON. DRIER AIR WILL MOVE INTO THE STATE FROM THE
NORTHWEST ON TUESDAY AND WEDNESDAY...LIMITING STORMS ACROSS THE
NORTHWEST...BUT STORMS ACROSS THE EAST REMAIN POSSIBLE AS A BACK
DOOR COLD FRONT SLIDES SOUTHWARD. TEMPERATURES WILL RUN NEAR TO A
FEW DEGREES ABOVE NORMAL THROUGH AT LEAST THE MIDDLE OF THE WEEK.
FORECAST CONFIDENCE REMAINS LOW ESPECIALLY BEYOND MID WEEK AS
MODELS CONTINUE TO FLIP FLOP ON TIMING AND STRENGTH OF ANOTHER
BACK DOOR COLD FRONT.
&&
.DISCUSSION...
FORECAST CONFIDENCE FOR THE NEXT 7 DAYS IS QUITE LOW DUE TO MODEL
INCONSISTENCIES. HENCE...EXPECT CHANGES FROM THE FOLLOWING.
GENERALLY...THE UPPER HIGH THAT IS CENTERED OVER WEST TEXAS TODAY
WILL SLOWLY SHIFT SOUTH OF NM THROUGH TUESDAY...BEFORE ELONGATING
FROM NW TO SE ACROSS SOUTHERN AZ INTO OLD MEXICO. MEANWHILE...
TROPICAL STORM LINDA HAS FORMED SOUTH OF THE BAJA AND IS FORECAST
TO MOVE NW THRU THIS TIME PERIOD. IT DOES NOT APPEAR AT THIS TIME
THAT NM WILL BENEFIT FROM TS LINDAS MOISTURE...AS THE UPPER HIGH
WILL BE BLOCKING IT FROM REACHING US.
AS FOR THE DETAILS...THAT IS WHERE IT GETS MURKY. FOR
TONIGHT...THE HRRR SEEMS TO HAVE A PRETTY GOOD HANDLE ON CURRENT
CONVECTION. THUS...EXPECT THE STORMS ALONG THE SACS TO CONTINUE TO
MOVE NEWD THIS EVENING...AS WELL AS ALONG A WEAK CONVERGENCE ZONE
ACROSS THE EASTERN PLAINS. THE HRRR ALSO DEPICTS AN UPSWING IN
ACTIVITY AFTER MIDNIGHT TONIGHT ACROSS THE SW AND SC AREAS AS A
WEAK DISTURBANCE MOVES UP IN SSW FLOW. OTHER MODELS ARE NOT
TERRIBLY ENTHUSIASTIC ABOUT THIS FEATURE DURING THE OVERNIGHT
PERIOD...BUT IT MAY BE AT LEAST IN PART A REASON WHY THE NAM IS
BREAKING OUT MUCH MORE PRECIPITATION ON MONDAY THAN OTHER
MODELS...SPECIFICALLY ACROSS THE EAST AND NORTH. THE DEGREE OF
DRYING FOR MONDAY DEPICTED BY ANY MODEL ACROSS THE NORTH IS NOT
NEARLY AS STRONG AS IT WAS 24 OR 48 HOURS AGO DESPITE THE MORE
WESTERLY FLOW ALOFT. SO STANDS TO REASON THAT MONDAY WILL BE MORE
ACTIVE THAN TODAY...AND ALSO THAT THE NAM MAY BE ONTO SOMETHING.
HOWEVER...THE AMOUNT OF MID AND HIGH CLOUDS THAT MAY BE AROUND DUE
TO OVERNIGHT CONVECTION...IF THE HRRR IS RIGHT...MAY DIMINISH SOME
OF THE POTENTIAL INSTABILITY.
THE DRY AIR DOES APPEAR TO COME INTO AT LEAST THE NW AND PERHAPS
NC AREAS ON TUESDAY... WHICH SHOULD LIMIT CONVECTION THERE. THE
BACK DOOR FRONT THAT IS EXPECTED TO COME INTO THE NE LOOKS
STRONGER... AND MODELS ARE EVEN SHOWING AN INCREASE IN DEWPOINTS
ON TUESDAY AND TUESDAY NIGHT BEHIND THE FRONT. THEREFORE...HAVE
BUMPED UP POPS SLIGHTLY ACROSS THE SANGRES TO ACCOUNT FOR THE
MOIST UPSLOPE FLOW. THE FRONT DOES LOOK TO PUSH FURTHER SOUTH AND
WEST THAN WHAT MODELS SHOWED YESTERDAY...PERHAPS EVEN OOZING THRU
THE GAPS OF THE CENTRAL MTN CHAIN WED MORNING. WOULD EXPECT THE
CENTRAL MTN CHAIN TO HAVE A FAIR AMOUNT OF ACTIVITY ON WEDNESDAY
AFTERNOON WITH CONTINUED UPSLOPE FLOW AS THE WINDS SLOWLY VEER
AROUND TO THE EAST AND SOUTHEAST ACROSS THE PLAINS...BUT MODELS DO
NOT SHOW A CLEAR SIGNAL OF THAT. THIS IS LIKELY BECOMES OF THE
DRIER MID LEVEL AIR CONTINUING TO MOVE INTO THE NW HALF OF NM.
THUS...THE LOW LEVEL MOISTURE AND UPSLOPE FLOW WILL LIKELY HAVE A
FIGHT WITH THE STABILITY AT MID LEVELS.
THE STRONG FRONT THAT WAS SUPPOSED TO ARRIVE THURSDAY NIGHT AND
FRIDAY...WELL...APPARENTLY THE MODELS HAVE DECIDED THAT IS NOT
GOING TO HAPPEN. AFTER SHOWING THAT SCENARIO FOR SEVERAL MODEL
RUNS...BOTH THE LATEST EC AND GFS SHOW ONLY A WEAK WIND SHIFT
ACROSS THE NE. THUS POP CHANCES DURING THIS PERIOD AND THRU
SATURDAY HAVE BEEN TRIMMED CONSIDERABLY. BUT AS STATED AT THE
BEGINNING...CONFIDENCE IS QUITE LOW AND MODELS MAY YO-YO BACK
TOMORROW.
34
&&
.FIRE WEATHER...
ANOTHER RELATIVELY SLOW DAY FOR CONVECTION SO FAR. SOME DRIER AIR
HAS PUSHED INTO THE WEST AND CENTRAL IN THE MID LEVELS ALLOWING LOW
LEVEL MOISTURE TO MIX OUT. SHORT TERM MODELS STILL INDICATE LOCALES
SOUTH OF INTERSTATE 40 AND ALONG/EAST OF THE PECOS WILL HAVE THE
BEST CHANCES FOR WETTING RAIN TONIGHT. IN GENERAL...CELL MOVEMENT
WILL AGAIN BE TO THE NORTHEAST FOR THE REST OF THIS AFTERNOON AND
TONIGHT.
MONDAY FEATURES SOMEWHAT MORE WESTERLY WINDS...AND WITH HIGHER POPS
ALONG AND SOUTH OF INTERSTATE 40 AS THE TAP OF MOISTURE IS NOT
TOTALLY CUT OFF. OTHERWISE...CONFIDENCE IN THE TIMING OF FRONTS FOR
THIS WEEK IS AT AN ALL TIME LOW. THE STRONGER BOUNDARY...AND PUSH OF
LOW LEVEL MOISTURE WESTWARD...COULD NOW BE TUESDAY/WEDNESDAY AS THE
GFS CONTINUES TO DOWNPLAY THE FRIDAY/SATURDAY BOUNDARY. SO...THERE
WILL LIKELY BE A BOUNDARY OR MORE THIS WEEK IMPACTING ERN NM...AND
ACCOMPANIED BY SLOSHING OF LOW LEVEL MOISTURE WWD TO THE CENTRAL MT
CHAIN AND EVEN INTO THE RGV...BUT WHEN IT WILL HAPPEN THE MODELS
CAN/T...SO FAR...SEEM TO PREDICT CONSISTENTLY. THIS WILL IMPACT
CHANCES FOR WETTING RAIN TO AT LEAST SOME EXTENT...AND DAY TO DAY
CHANGES IN RH AND TEMPERATURES. CURRENT TRENDS THOUGH ARE FOR HIGHER
POPS TO SHIFT TO THE CENTRAL MT CHAIN/SOUTHEAST HALF OF THE FORECAST
AREA BY MIDWEEK...THEN DIMINISH OVERALL NEXT WEEKEND.
WHAT DOES APPEAR LESS VARIABLE IS ADDITIONAL DRYING OF WRN NM FROM
THE CONTDVD TO THE AZ BORDER. MID TO LATE WEEK...HIGH HAINES IS
FORECAST OVER THIS REGION AND LATE DAY DEW POINTS FALL INTO THE 30S
WITH EVEN SOME 20S THE FARTHER NORTH AND WEST YOU GO. CONSEQUENTLY
OVERNIGHT RH RECOVERIES LOOK TO BE FAIR TO EVEN POOR NORTHWEST BY
THURSDAY/FRIDAY NIGHT WHILE MIN RH VALUES FALL BELOW 15 PERCENT.
FORECAST VENT RATES MOSTLY GOOD TO EXCELLENT MONDAY/TUESDAY THEN
DECREASE SOME WEDNESDAY/THURSDAY WITH AREAS OF FAIR TO POOR CENTRAL
AND NORTH. FORECAST HIGHS WILL RUN WITHIN A FEW DEGREES OF AVERAGE
THRU WEDNESDAY/THURSDAY.
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
11
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
348 AM CDT MON SEP 7 2015
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 348 AM CDT MON SEP 7 2015
THE MAIN CHALLENGE THIS PERIOD WILL BE SHOWER CHANCES AND
TEMPERATURES. THE AIRMASS CHANGE HAS OCCURRED WITH MUCH COOLER
AND DRIER ADVECTING INTO THE REGION. UPPER LOW WILL SLOWLY
PROPAGATE EAST ACROSS CANADA...AND MOST MODEL GUIDANCE SUGGESTS A
WAVE WITHIN THIS FLOW PATTERN WILL LEAD TO SHOWERS THIS AFTERNOON.
GIVEN THE DRY AIRMASS IN PLACE ANY RADAR RETURNS WILL LIKELY
APPEAR WORSE THAN WHAT IS OCCURRING AT THE GROUND...BUT DID
INCLUDE ISOLD SHOWERS AS HRRR INDICATES WEAK BANDING POTENTIAL.
ANTICIPATE SOLAR TODAY...WHICH SHOULD ALLOW MAX TEMPS INTO THE
70S.
DRY ON TUESDAY...AND SLIGHTLY COOLER AS THE UPPER LOW IN CANADA
SHIFTS EAST.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 348 AM CDT MON SEP 7 2015
WEDNESDAY...UPPER WAVE IN NORTHWEST FLOW ALOFT WILL PROVIDE SHOWER
CHANCES...ALTHOUGH MOST 00Z GUIDANCE IS SLOWER AND TIMES THIS
FORCING INTO THE REGION MORE WEDNESDAY NIGHT. THIS WOULD ALLOW
SLIGHTLY WARMER TEMPERATURES DURING THE DAY ON WED. TRENDED THE
FORECAST ACCORDINGLY FOR POPS AND TEMPS.
THURSDAY-SUNDAY...LOW AMPLITUDE LONG WAVE RIDGE/TROUGH OVER
WESTERN CANADA/CENTRAL NORTH AMERICA RESPECTIVELY AMPLIFIES A BIT
BY THE END OF THE PERIOD. THE GFS WAS A FASTER AND A LOWER
AMPLITUDE SOLUTION THAN THE ECMWF. BOTH THE ECMWF AND THE GFS HAVE
BEEN TRENDING SLOWER OVER THE LAST COUPLE MODEL RUNS. TEND TO
PREFER THE ECMWF.
HIGH TEMPS WERE INCREASED ONE TO THREE DEGREES FOR THU AND INCREASED
ONE OR TWO DEGREES FOR FRI AND SAT. HIGH TEMPS WERE DECREASED TWO TO
THREE DEGREES FOR SUN FROM YESTERDAYS FORECAST PACKAGE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1145 PM CDT SUN SEP 6 2015
VFR THRU THE PERIOD. GENERALLY CLEAR WITH LIGHT WINDS OVERNIGHT.
COULD BE PATCHY RADIATIONAL FOG NR SUNRISE BEMIDJI AREA...BUT
CONFIDENCE IS QUITE LOW AND ANY FOG WILL BE SPOTTY SO WILL KEEP
VSBY P6SM. OTHERWISE INCREASE IN HIGH AND MID CLOUDS THRU THE DAY
MONDAY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...TG
LONG TERM...TG/HOPPES
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1148 PM CDT SUN SEP 6 2015
.UPDATE...
ISSUED AT 1145 PM CDT SUN SEP 6 2015
SKIES CLEAR AND WINDS BECOMING LIGHT. SOME THIN CIRRUS ENTERING
WRN ND AND WILL SPREAD NORTHEAST OVERNIGHT. LATEST HRRR MODEL RUNS
DONT INDICATE ANY FOG...SO WILL NOT MENTION. WILL STILL NEED TO
KEEP AN EYE ON IT THOUGH IN THE FAR EASTERN FCST AREA.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 350 PM CDT SUN SEP 6 2015
REST OF THE AFTERNOON AND EVENING...A WEAK FRONTAL BOUNDARY DRAPED
ALONG THE BDE-BJI-PKD-ETH LINE WILL SLOWLY SHIFT EASTWARD AND
PROVIDE SOME FOCUS FOR STRONG SHOWER AND THUNDERSTORM DEVELOPMENT.
BEHIND THIS BOUNDARY IN NORTHWEST MINNESOTA... ISOLATED ELEVATED
CONVECTION IS POSSIBLE THROUGH THE LATE AFTERNOON PERIOD. BY 00Z
THUNDERSTORM ACTIVITY WILL HAVE MOVED INTO CENTRAL AND EASTERN
PORTIONS OF MINNESOTA... WITH A SOMEHWAT DRIER WESTERLY FLOW
PERSISTING INTO THE OVERNIGHT HOURS.
LABOR DAY...SOME PATCHY GROUND FOG IS POSSIBLE OVER THE MINNESOTA
LAKES COUNTRY IN THE EARLY MORNING. OTHERWISE...EXPECT GENERALLY
FAIR SKIES INTO MIDDAY AND SEASONABLY MILD CONDITIONS THROUGHOUT
THE DAY. A LIGHT SOUTHERLY BREEZE WILL TURN LIGHT AND VARIABLE
THROUGH THE AFTERNOON AS SURFACE HIGH PRESSURE MOVES INTO CENTRAL
MINNESOTA. AREAS OF FAIRLY HIGH BASED AND SHALLOW CUMULUS CLOUDS
WILL LIKELY DEVELOP IN THE AFTERNOON... AND AN ISOLATED SPRINKLE
IS POSSIBLE... BUT MEASURABLE PRECIPITATION IS NOT EXPECTED.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 350 PM CDT SUN SEP 6 2015
TUESDAY THROUGH WEDNESDAY...A FAIRLY BROAD AND SHALLOW H5 TROF
SETS UP ACROSS THE NORTHERN PLAINS FOR THE EARLY WEEK PERIOD WITH
WEST-NORTHWESTERLY FLOW ALOFT OVER THE AREA. MODELS ARE FAIRLY
CONSISTENT IN MAINTAINING AN OVERALL DRY FLOW OVER MOST OF THE
DAK-MINN AREA THROUGH TUESDAY... WITH SOME MOISTURE AND ENERGY
DROPPING INTO THE AREA ON WEDNESDAY.
WEDNESDAY NIGHT THROUGH SUNDAY...FLOW TRANSITIONS FROM TROUGHING
AND NORTHWESTERLY FLOW ALOFT TO MORE ZONAL AS A TROUGH DIGS INTO
THE UPPER MIDWEST AND THEN MOVES EAST. SOME SHOWERS WILL LINGER
INTO WEDNESDAY NIGHT AND THURSDAY AS A REINFORCING SURGE OF COOL
AIR COMES DOWN...BUT THE END OF THE WEEK SHOULD BE DRY. LOWERED
THE BLENDED POPS A BIT TO REMOVE MENTION OF PRECIP THURSDAY NIGHT
AND FRIDAY AS WE SHOULD BE FIRMLY UNDER HIGH PRESSURE BY THEN.
ANOTHER APPROACHING FRONT ON SUNDAY COULD BRING A CHANCE FOR
PRECIP...BUT WITH A LOT OF VARIATION ON TIMING KEPT CHANCES LOW.
TEMPS WILL BE COOLER THAN AVERAGE AT THE START OF THE PERIOD BUT
WILL WARM UP INTO NEXT WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1145 PM CDT SUN SEP 6 2015
VFR THRU THE PERIOD. GENERALLY CLEAR WITH LIGHT WINDS OVERNIGHT.
COULD BE PATCHY RADITIONAL FOG NR SUNRISE BEMIDJI AREA...BUT
CONFIDENCE IS QUITE LOW AND ANY FOG WILL BE SPOTTY SO WILL KEEP
VSBY P6SM. OTHERWISE INCREASE IN HIGH AND MID CLOUDS THRU THE DAY
MONDAY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...RIDDLE
SHORT TERM...GUST
LONG TERM...GUST/JR
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS NORMAN OK
347 AM CDT MON SEP 7 2015
.DISCUSSION...
HOT WEATHER TODAY AND TUESDAY IS THE FIRST CONCERN...THEN RAIN
CHANCES MAINLY TUESDAY...WEDNESDAY...AND THURSDAY NIGHT AS WELL
AS COOLER WEATHER ARE THE NEXT CONCERNS.
THIS MORNING...LATEST HRRR RUNS HAVE BEEN HINTING THAT A FEW
HIGH BASED SHOWERS AND THUNDERSTORMS MAY FORM OVER NORTHERN
OKLAHOMA...NORTH OF A ELK CITY TO STILLWATER LINE. FOR NOW...DID
NOT MENTION AS NOT SURE THIS WILL OCCUR DUE TO DECENT CAPPING.
THIS AFTERNOON AND EARLY EVENING...A FEW THUNDERSTORMS MAY FORM
SIMILAR TO YESTERDAY IN PARTS OF SOUTHERN OKLAHOMA...MAINLY SOUTH
OF A ARDMORE TO COALGATE LINE AS WELL AS PERHAPS FAR NORTHWESTERN
OKLAHOMA CLOSER TO A FRONT. KEPT 20 PERCENT CHANCES IN THESE
LOCATIONS. ANY STORM WILL MOVE FAIRLY SLOWLY AND BE CAPABLE OF
PRODUCING GUSTY WINDS UP TO 50 MPH AND WELL AS LOCALIZED
DOWNPOURS.
THE HEAT TODAY WILL BE THE MAIN STORY. THINK HIGHS WILL BE VERY
SIMILAR TO YESTERDAY. GENERALLY WENT TOWARDS THE HOTTER SIDE OF
MODEL GUIDANCE. WILL HOLD OFF ON ISSUING A HEAT ADVISORY THOUGH
HEAT INDICES WILL FLIRT WITH THE 105 DEGREE MARK IN MANY
LOCATIONS.
LATE TONIGHT INTO TUESDAY MORNING...A FEW STORMS MAY FORM NEAR
THE APPROACHING COLD FRONT IN NORTHERN OKLAHOMA. KEPT 20 PERCENT
CHANCES TO ACCOUNT FOR THIS. OTHERWISE...RAINFREE AND MUGGY
CONDITIONS WILL PERSIST.
TUESDAY AFTERNOON AND NIGHT...RAIN CHANCES WILL INCREASE ACROSS
THE ENTIRE AREA WITH THE PASSAGE OF A COLD FRONT. STORMS MAY BE
NEAR THE FRONT AND PERHAPS ORGANIZE INTO A LINE. A FEW STORMS MAY
BE STRONG TO PERHAPS SEVERE WITH DAMAGING WINDS UP TO 70 MPH AS
THE MAIN HAZARDS AS DCAPE VALUES WILL EXCEED 1000 J/KG IN A HOT
DEEPLY MIXED ENVIRONMENT. NOT SURE IF STORMS WILL BECOME TOO
WIDESPREAD AND VERY ORGANIZED AS 0-6 KM SHEAR MAY BE MARGINAL.
LOCALLY HEAVY RAINFALL COULD OCCUR AS WELL. HIGHEST RAIN CHANCES
APPEAR TO BE NEAR AND EAST OF I-35.
HIGHS ON TUESDAY MAY SOAR JUST AHEAD OF THE COLD FRONT...THUS WENT
ABOVE MODEL GUIDANCE IN MOST LOCATIONS EXCEPT FAR NORTHERN
OKLAHOMA WHERE MORE CLOUDS AND RAIN MAY KEEP THEM DOWN A BIT.
WEDNESDAY...SOME SHOWERS AND STORMS MAY LINGER OVER SOUTHERN
OKLAHOMA AND WESTERN NORTH TEXAS...MAINLY DURING THE MORNING
HOURS. COOLER TEMPERATURES WILL LIKELY RESULT...THOUGH IT MAY
REMAIN FAIRLY MUGGY.
WEDNESDAY NIGHT THROUGH SUNDAY...COOLER WEATHER IS STILL
FORECAST...THOUGH THERE IS SOME UNCERTAINTY DURING THIS TIME FRAME
WITH THE TIMING OF SYSTEMS AND HOW COOL IT WILL BE. LATEST MODELS
WERE NOT QUITE AS COOL DURING THIS TIME FRAME. THERE SEEMED TO BE
SIGNAL FOR STORMS THURSDAY NIGHT ACROSS MUCH OF THE AREA. RAIN
CHANCES WERE KEPT THURSDAY NIGHT THROUGH SATURDAY NIGHT ACROSS
PARTS OF THE AREA...THOUGH TIMING AND LOCATIONS REMAIN UNCERTAIN.
MBS
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 99 74 96 69 / 10 10 30 60
HOBART OK 103 75 101 69 / 0 10 30 50
WICHITA FALLS TX 100 73 100 72 / 10 0 10 60
GAGE OK 101 76 94 64 / 10 10 40 30
PONCA CITY OK 99 77 91 67 / 10 10 50 70
DURANT OK 97 74 97 72 / 20 20 20 70
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
17
AREA FORECAST DISCUSSION
NWS TULSA OK
1135 PM CDT SUN SEP 6 2015
.DISCUSSION...
The 06z TAF discussion is included below...
&&
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
The theme of the 00z forecast remains in tact. Still some
potential as suggested in the latest runs of the HRRR that some
high based tsra is possible toward 12z across NE OK. Some light
mvfr fog is possible near sunrise at KBVO, KFYV, and KROG.
Afternoon isolated storms are expected to develop in the terrain
again over in SE OK and NW AR...with KFSM standing the greatest
risk of being affected. For both convective scenarios...confidence
and coverage were not great enough to go with TEMPO...so will
instead go the conservative VCTS route.
Lacy
&&
.PREV DISCUSSION... /ISSUED 738 PM CDT SUN SEP 6 2015/
DISCUSSION...
Sent out an early update this evening as area 88Ds indicate afternoon
convection has pretty much all dissipated at this time, so we
removed mention of thunderstorms this evening. As previous discussion
indicated, we have also added slight chance POPs for nern OK and far
nwrn AR late tonight/Monday morning. Short-term models hint at some
high-based convection developing into our CWA after 09z as mid-levels
moisten/destabilize. Will likely result in a bit more cloudiness
Monday morning but not enough to impact expected max temperatures
later in the day. Updated products already issued...
PREV DISCUSSION... /ISSUED 705 PM CDT SUN SEP 6 2015/
DISCUSSION...
The 00z taf discussion is included below...
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
Ridging remains in place aloft...which will maintain VFR
conditions for the most part thru this forecast period.
However...there are a few possible exceptions or things to note.
The latest data indicates mid level moistening that could produce
some high based thunderstorms around sunrise and into the morning
hours across NE OK. In addition...some light MVFR fog is possible
over in NW AR around sunrise as well. By tomorrow
afternoon...daytime heating will produce isolated thunderstorms
over in the terrain of SE OK/W AR. KFSM stands the best chance of
being affected. With both of the convective scenarios
discussed...confidence and coverage would suggest staying
conservative...so will use VCTS mention instead of prob30 or TEMPO
for now.
Lacy
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 75 96 76 93 / 20 20 10 20
FSM 75 96 74 93 / 10 20 10 20
MLC 75 96 75 94 / 10 10 10 20
BVO 70 95 71 91 / 20 20 10 40
FYV 69 90 71 89 / 10 10 10 30
BYV 69 91 70 89 / 10 20 10 30
MKO 74 95 74 93 / 10 10 10 20
MIO 74 94 75 90 / 20 20 10 40
F10 75 96 75 94 / 10 10 10 20
HHW 75 97 74 95 / 10 20 10 20
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...30
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
319 AM CDT MON SEP 7 2015
.DISCUSSION...
LATEST SURFACE OBSERVATIONS SHOWS TEMPERATURES IN THE 60S TO LOW
70S ACROSS THE MID STATE WITH DEWPOINTS ALSO IN THE 60S UNDER
NEARLY CLEAR SKIES. SEVERAL OBS ALSO SHOWING PATCHY FOG ALTHOUGH
NO DENSE FOG HAS BEEN NOTED THUS FAR. WILL KEEP MENTION OF PATCHY
FOG IN THE GRIDS/ZONES THROUGH 14Z. OTHERWISE...ANOTHER HOT AND
HUMID DAY IS ON TAP WITH TEMPERATURES RISING INTO THE 80S PLATEAU
AND LOW 90S ELSEWHERE...SIMILAR TO YESTERDAY. WATER VAPOR IMAGERY
DEPICTS AN UPPER LEVEL LOW CENTERED OVER GEORGIA...WITH DRY AIR ON
THE WEST SIDE OF THE LOW CURRENTLY ACROSS THE MID STATE. 00Z
GFS/ECMWF SLOWLY RETROGRADE THIS LOW TO THE SOUTHWEST OVER THE
NEXT FEW DAYS WHILE MOISTURE ADVECTS WESTWARD AROUND THE NORTH
SIDE OF THE LOW INTO MIDDLE TENNESSEE. THUS EXPECTING ISOLATED
SHOWERS AND STORMS AGAIN TODAY...BUT MAINLY TO THE EAST OF I-65 AS
THE DRY AIR ALOFT LIMITS COVERAGE OVER WESTERN ZONES. THIS
THINKING IS IN LINE WITH THE LATEST HRRR MODEL RUNS WHICH KEEPS
CONVECTION MAINLY OVER THE EASTERN HALF OF THE CWA.
POPS WILL INCREASE WESTWARD ON TUESDAY AS PWATS RISE BACK ABOVE
1.5 INCHES ACROSS MUCH OF THE FORECAST AREA. BY WEDNESDAY...THE
MAIN BELT OF WESTERLIES ACROSS THE NORTHERN CONUS BEGINS TO SINK
SOUTHWARD ACROSS THE TENNESSEE VALLEY...WITH A COLD FRONT PROGGED
TO MOVE ACROSS THE FORECAST AREA ON THURSDAY. THE INCREASE IN
UPPER LEVEL SUPPORT ALONG WITH PWATS RISING TO AROUND 1.75 INCHES
AND THE FRONTAL FOCUS ALL INDICATE FAIRLY WIDESPREAD SHOWERS AND
STORMS WEDNESDAY INTO THURSDAY...WARRANTING CHANCE TO LIKELY POPS
ALONG WITH MUCH COOLER HIGH TEMPS DUE TO PRECIP/CLOUD COVER. 00Z
GFS/ECMWF INDICATE AREA WILL DRY OUT ON FRIDAY...BUT A FEW SHOWERS
ARE POSSIBLE FRIDAY NIGHT AND SATURDAY AS A SECONDARY SURGE OF
COOLER AIR MOVES ACROSS. VERY PLEASANT FALL-LIKE CONDITIONS ARE
ANTICIPATED SATURDAY AND SUNDAY WITH LOW HUMIDITY AND
TEMPERATURES SEVERAL DEGREES BELOW NORMAL FOR THIS TIME OF YEAR.
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 92 70 92 71 / 20 0 20 10
CLARKSVILLE 93 67 92 69 / 10 0 10 0
CROSSVILLE 84 65 84 67 / 20 10 20 20
COLUMBIA 91 67 91 69 / 10 0 20 10
LAWRENCEBURG 89 68 89 69 / 10 0 20 20
WAVERLY 91 67 92 69 / 10 0 10 10
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHAMBURGER
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
356 AM CDT MON SEP 7 2015
.SHORT TERM...
(Today and Tonight)
It will be another persistence forecast today, with the upper
ridge parked over West Central Texas. The HRRR model again
develops isolated afternoon convection, as it has done the last
several days, and will discount the potential. Temperatures should
again rise into the upper 90s with a few areas reaching 100.
04
.LONG TERM...
(Tuesday through Sunday)
We looking for one more hot and dry day across west central TX
before the synoptic pattern shifts to one more conducive for
increasing rain chances and more seasonal temperatures. The
subtropical ridge will be building slowly westward on Tuesday as a
strong trough moves across the northern Plains. This trough is
progged to dig over the eastern CONUS, allowing the ridge to build
over the western states. This will result in northwest flow aloft
for our neck of the woods. A weak cold front will move south into
the Lone Star State Tuesday afternoon, likely reaching the south
Plains during the evening hours. Compressional heating ahead of
this cold front will promote afternoon highs in the mid 90s to
near 100 degrees.
Convection is expected to initiate along this cold front as it
approaches Tuesday evening. Some of this activity is expected to
move southeast into the Big Country, maybe as far south as the
Colorado River, Tuesday night into early Wednesday morning. The
cold front is expected to weaken by this time, but convective
outflow should serve as the effective frontal boundary, moving
south into the Concho Valley, and eventually the I-10 corridor,
by Wednesday afternoon. Scattered showers and thunderstorms are
expected to develop, especially along and behind the front. While
rainfall is not expected to be particularly heavy, it should be
fairly widespread with good coverage across the CWA. The increased
cloud cover and precipitation will keep temperatures in check.
Forecast highs for Wednesday afternoon are in the upper 80s to
lower 90s; however, they could be lowered further if rain is
indeed as widespread as anticipated.
The effective cold front will move south over the Edwards Plateau
Wednesday night into Thursday. This will shift the highest rain
chances south of a San Angelo-Brownwood line, favoring the I-10
corridor. In fact, PoPs were removed for areas north of I-20 on
Thursday. This boundary will become more diffuse by the end of the
work-week, but slight chance PoPs were retained over the southern
1/3 of the CWA for Friday. Total rainfall amounts will likely
average less than 1/2 inch, some some areas will see locally
higher amounts, especially over the southeast quadrant of the CWA.
Temperatures are forecast to remain near seasonal norms Thursday
and Friday, generally in the upper 80s to lower 90s. Overnight
lows during this time will be in the mid 60s to near 70 degrees.
PoPs were removed over the weekend as the main upper-level trough
is expected to be to our east by Saturday. Temperatures are
expected to remain near climatology. There remain some differences
in the synoptic pattern, the most notable of which is the tropical
system generated early next week in the western Gulf by the ECMWF.
At the same time, the GFS creates no such system and maintains a
weak cut-off upper-low over the Red River. Will continue to
monitor the model trends at this time, keeping a dry forecast over
the weekend.
Johnson
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 99 76 98 73 / 0 0 5 30
San Angelo 100 75 100 74 / 0 0 0 10
Junction 98 74 97 75 / 0 0 5 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
04/25
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1158 PM CDT SUN SEP 6 2015
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 249 PM CDT SUN SEP 6 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A COLD
FRONT RUNNING SOUTHWEST FROM NORTHERN MINNESOTA TO EASTERN SOUTH
DAKOTA EARLY THIS AFTERNOON. DESPITE ML CAPES UPWARDS OF 2000 J/KG
OVER CENTRAL MINNESOTA...THE FRONT IS MOSTLY INACTIVE AS A RESULT OF
CIN GREATER THAN 100 J/KG. STILL RATHER UNCERTAIN HOW CONVECTION
WILL EVOLVE LATER THIS AFTERNOON. MOST MESOMODELS SHOW CONVECTION
DEVELOPING AFTER 21Z...BUT THIS WILL BE AROUND THE SAME TIME AS THE
RIGHT FRONT QUAD OF A JET STREAK MOVES OVERHEAD. AS A
RESULT...THINK CONVECTION WILL NOT BE AS ROBUST AS THE ARW/NMM...AND
MORE ISOLATED TO SCATTERED LIKE THE HRRR. OTHERWISE...THE MID-LEVEL
THETAE AND PWAT PLUME WILL CONTINUE TO PUSH IN SCATTERED LIGHT
SHOWERS AND ISOLATED TSTORMS FOR THE REST OF THE AFTERNOON INTO
CENTRAL AND N-C WISCONSIN. TEMPS MAY NOT GET TO THEIR EARLIER
FORECAST HIGHS IN THESE AREAS AS A RESULT. AS THE COLD FRONT MOVES
EAST TONIGHT...THUNDERSTORMS CHANCES AND IMPACTS ARE THE MAIN
FORECAST CONCERNS.
TONIGHT...THE COLD FRONT WILL MOVE EAST TONIGHT...REACHING N-C
WISCONSIN BY 06Z AND NORTHEAST WISCONSIN BY 12Z. AT LEAST SCT
CONVECTION STILL LOOKS TO FIRE OVER MINNESOTA...BUT THINK IT WILL
REMAIN RATHER UNORGANIZED TO THE LARGE CIN AND UPPER LEVEL
SUBSIDENCE. BUT AS THE FRONT DRAWS CLOSER TO THE PWAT PLUME OVER
WESTERN WISCONSIN...THE ECMWF/GFS/GEM ALL DEVELOP WIDESREAD SHOWERS
AND STORMS AFTER 00Z. ALONG WITH PWATS GREATER THAN 2.0
INCHES...ELEVATED INSTABILITY WILL REACH 1000-2000 J/KG WITH LITTLE
TO NO CIN. SO WENT WITH THIS IDEA IN THE FORECAST...INCREASING
PRECIP CHANCES QUICKLY IN THE 00-03Z TIME PERIOD. PRECIP IS
EXPECTED TO WEAKEN SOME BY THE TIME IT REACHES THE LAKE MICHIGAN
SHORELINE LATE TONIGHT. SINCE EFFECTIVE BULK SHEARS WILL GENERALLY
BE UNDER 20 KTS BY THE TIME CONVECTION DEVELOPS...THINK ANY SEVERE
THREAT IS RATHER LOW. ISOLATED STRONG GUSTY WINDS STILL APPEAR
REASONABLE...ALONG WITH LOCALLY HEAVY RAINFALL.
MONDAY...THE FRONT WILL STILL BE BISECTING THE FORECAST AREA FROM NE
WI TO CENTRAL WI AT THE START OF THE MORNING. SCT SHOWERS AND
STORMS WILL BE POSSIBLE ALONG THE FRONT OVER CENTRAL AND FAR NE
WISCONSIN DURING THE MORNING...AND EAST-CENTRAL WI THROUGH LATE
AFTERNOON. CLOUD COVER SHOULD BE WIDESPREAD AHEAD OF THE
FRONT...BUT IF CLOUDS DO BREAK FOR A PERIOD...INSTABILITY OVER EAST-
CENTRAL WI COULD BECOME SUFFICIENT FOR STRONG STORMS TO DEVELOP.
SEVERE STORMS ARE UNLIKELY GIVEN THE POOR SHEAR OF 15-20KTS. BEHIND
THE FRONT...N-C WI SHOULD SEE CLEARING TAKE PLACE IN THE AFTERNOON
AFTER A CLOUDY START. COOLER HIGHS IN THE MID 70S TO LOW 80S.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 249 PM CDT SUN SEP 6 2015
THE COLD FRONT WILL MAKE IT INTO SOUTHERN WISCONSIN OR NORTHERN
ILLINOIS MONDAY NIGHT BEFORE RETURNING NORTHWARD AS A WAVE MOVES
NORTHEAST ALONG THE FRONT. THE FRONT WILL BE SHALLOW SO THERE WILL
LIKELY BE OVERRUNNING SHOWERS AND THUNDERSTORMS ACROSS THE
SOUTHEAST HALF OF THE FORECAST AREA TUESDAY. THE FRONT SHOULD MOVE
FAR ENOUGH SOUTH WEDNESDAY FOR DRIER AIR TO RETURN FOR AWHILE. IT
WILL ALSO BE COOLER AND LESS HUMID.
AN UPPER TROUGH WILL MOVE ACROSS THE REGION THURSDAY AND BRING A
CHANCE OF SHOWERS FOLLOWED BY NORTHWEST UPPER FLOW AND MUCH COOLER
AND DRIER AIR FOR THE REMAINDER OF THE WEEK. LOWS IN THE 30S ARE
POSSIBLE IN FAR NORTHERN WISCONSIN FRIDAY NIGHT.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1155 PM CDT SUN SEP 6 2015
SHOWERS AND EMBEDDED TSTMS WILL CONTINUE TO MOVE THROUGH THE
REGION OVERNIGHT...WITH POCKETS OF HEAVY RAINFALL...AND ASSOCIATED
MVFR/IFR CONDITIONS. PATCHY LOW CLOUDS (POSSIBLE IFR/LIFR) MAY
ALSO ACCOMPANY THE FRONTAL PASSAGE AND LINGER INTO MONDAY MORNING
BEFORE ERODING/LIFTING. CONDITIONS SHOULD IMPROVE TO VFR AT MOST
LOCATIONS BY EARLY MONDAY AFTERNOON.
KEPT LLWS IN THE GRB/ATW/MTW TAFS FOR THE FIRST FEW HOURS OF THE
TAF PERIOD...WITH WSW WINDS AROUND 35 KTS AROUND 1000 FT AGL.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......RDM
AVIATION.......KIECKBUSCH
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
958 AM EDT MON SEP 7 2015
.SYNOPSIS...
BROAD UPPER LEVEL LOW OVER THE SOUTHEASTERN STATES WILL SHIFT
SOUTHWESTWARD INTO THE GULF OF MEXICO THROUGH TUESDAY AS SURFACE
HIGH PRESSURE BUILDS IN FROM THE NORTH. DEEP AND MOIST FLOW FROM
THE ATLANTIC WILL CONTINUE ACROSS THE REGION. AN UPPER RIDGE WILL
BUILD OVER THE AREA BY MID WEEK BRINGING WARMING TEMPERATURES. A
COLD FRONT AND UPPER TROUGH WILL BRING UNSETTLED WEATHER FOR THE
END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
SURFACE HIGH PRESSURE OVER THE MID-ATLANTIC STATES WILL CONTINUE
TO RIDGE INTO THE CAROLINAS AND GEORGIA THROUGH TONIGHT. BROAD UPPER
LEVEL LOW CENTERED OVER AL/GA BORDER WILL SHIFT SOUTHWESTWARD
INTO THE GULF OF MEXICO. DEEP AND MOIST FLOW FROM THE ATLANTIC
COMBINED WITH WEAK INSTABILITY WILL HOLD THE CHANCE OF SHOWERS AND
THUNDERSTORMS ACROSS THE AREA THOUGH THE EVENING. MOSTLY CLOUDY
SKIES EXPECTED.
SPC HRRR INDICATING SCATTERED CONVECTION PUSHING INTO THE AREA
FROM THE COAST THIS AFTERNOON. CHANCE POPS LOOK REASONABLE FOR
THE AFTERNOON. PRECIPITABLE WATER VALUES GENERALLY AT OR ABOVE 2.0
INCHES SO LOCALLY HEAVY RAIN POSSIBLE. CONVECTION SHOULD WEAKEN
DURING THE EVENING HOURS WITH LOSS OF DAYTIME HEATING.
HIGH TEMPERATURES EXPECTED TO REACH THE MID AND UPPER 80S WITH
LOWS TONIGHT IN THE UPPER 60S TO LOWER 70S.
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
CLOSED UPPER LOW CENTERED ALONG THE GULF COAST STATES WILL CONTINUE
TO SLOWLY RETROGRADE AND FILL...WHILE WEAK UPPER RIDGING EXPANDS
OVER THE SOUTHEASTERN STATES FROM THE WESTERN ATLANTIC. THE SURFACE
PATTERN IS WEAK WITH HIGH PRESSURE CENTERED OVER VIRGINIA WEAKENING
WHILE A PERSISTENT SOUTHEASTERLY FLOW CONTINUES TO USHER MOISTURE
INLAND OFF THE ATLANTIC. PRECIPITABLE WATER VALUES WILL GRADUALLY
INCREASE TO AROUND 2 INCHES BY TUESDAY AFTERNOON AND REMAIN HIGH
THROUGH WEDNESDAY AS SOUTHERLY WINDS DEVELOP THROUGH THE LOWEST
20KFT OF THE ATMOSPHERE IN RESPONSE TO A TROUGH MOVING THROUGH THE
UPPER MISSISSIPPI AND OHIO VALLEYS.
WILL CONTINUE TO ADVERTISE HIGH CHANCE POPS ACROSS MUCH OF THE
REGION ON TUESDAY WITH THE HIGHEST POPS ACROSS THE SOUTHERN HALF OF
THE FORECAST AREA. THE THREAT OF SEVERE WEATHER APPEARS LOW WITH
PREDOMINATELY MOIST PROFILES AND WEAK SHEAR BUT HEAVY RAIN MAY BE A
CONCERN WITH STRONGER AND SLOW MOVING STORMS. SCATTERED UNORGANIZED
CONVECTION AGAIN EXPECTED ON WEDNESDAY WITH CONTINUED ELEVATED
MOISTURE PROFILES AND SLIGHTLY BETTER INSTABILITY. TEMPERATURES ON
TUESDAY AND WEDNESDAY WILL BE WARMER THAN THE PREVIOUS COUPLE OF
DAYS AND EXPECT HIGHS TO PUSH BACK INTO THE LOWER 90S WITH LOWS IN
THE LOWER 70S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
THE EXTENDED FORECAST FEATURES WHAT LOOKS LIKE AN ACTIVE WEATHER
REGIME WITH A MEAN TROUGH SETTING UP ACROSS THE EASTERN HALF OF
THE COUNTRY. AN INITIAL UPPER TROUGH WILL PUSH INTO THE REGION
FROM THE NORTHWEST ON THURSDAY RESULTING IN HEIGHT FALLS WHILE A
SURFACE TROUGH DEVELOPS OVER THE FORECAST AREA. THE SHORTWAVE
TROUGH IS FORECAST TO TRAVERSE THE FORECAST AREA THURSDAY NIGHT
INTO FRIDAY AND PUSH OFFSHORE BY FRIDAY NIGHT AS A COLD FRONT
PUSHES INTO THE AREA AND STALLS. THE FRONT WILL REMAIN STATIONARY
OVER THE REGION SATURDAY PROVIDING A FOCUS FOR PRECIPITATION AS
SOUTHWESTERLY FLOW ALOFT INCREASES IN ADVANCE OF ANOTHER SHORTWAVE
TROUGH DIGGING ACROSS THE OHIO VALLEY. THIS TROUGH WILL PUSH YET
ANOTHER FRONT INTO THE REGION BY EARLY SUNDAY AS A 1020MB SURFACE
RIDGE SETTLES ACROSS THE OHIO VALLEY INTO THE MID ATLANTIC STATES
BY SUNDAY NIGHT.
WILL CONTINUE MENTION OF SOLID CHANCE POPS THURSDAY AND FRIDAY WITH
THE FOCUS OF HIGHER POPS SHIFTING TO THE SOUTHEASTERN PART OF THE
AREA ON SATURDAY AND SUNDAY. TEMPERATURES DURING THIS PERIOD WILL
GENERALLY BE ABOVE NORMAL EARLY IN THE PERIOD AND NEAR NORMAL OVER
THE WEEKEND.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
MVFR CIGS EXPECTED TO LIFT TO VFR AROUND MID-DAY WHICH ALIGNS
WELL WITH THE PERSISTENCE FORECAST. CHANCE FOR SHOWERS WITH
ISOLATED THUNDER IN DEEP AND MOIST EASTERLY FLOW GIVEN WEAK
INSTABILITY. THE BEST CHANCE SOUTH AND EAST...FROM OGB TO AGS/DNL.
WILL MENTION VCSH MAINLY FOR THE AFTERNOON AND EARLY EVENING
HOURS. WINDS WILL BE OUT OF THE NORTHEAST TO EAST AT 10 KNOTS OR
LESS. MODELS INDICATING MVFR/IFR CIGS RETURNING AFTER 08/06Z.
EXTENDED AVIATION OUTLOOK...LATE NIGHT/MORNING FOG/STRATUS
POSSIBLE...WITH A CHANCE OF AFTERNOON SHOWERS AND POSSIBLE
THUNDERSTORMS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
643 AM EDT MON SEP 7 2015
.SYNOPSIS...
AN UPPER LOW OVER THE FORECAST AREA WILL SHIFT SOUTHWESTWARD
THROUGH TODAY WITH A COOL AND MOIST FLOW OFF THE ATLANTIC. AN
UPPER RIDGE WILL BUILD OVER THE AREA BY MID WEEK BRINGING WARMING
TEMPERATURES. A COLD FRONT AND UPPER TROUGH WILL BRING UNSETTLED
WEATHER FOR THE END OF THE WEEK.
&&
.NEAR TERM /TODAY AND TONIGHT/...
SURFACE ANALYSIS SHOWS AN AREA OF HIGH PRESSURE CENTERED OVER NEW
ENGLAND CONTINUING TO RIDGE DOWN THE EAST COAST INTO THE
CAROLINAS. MEANWHILE AN UPPER AREA OF LOW PRESSURE IS MOVING
WESTWARD THROUGH THE SOUTHEAST.
LATEST RADAR LOOP SHOWING SCATTERED SHOWERS BEING CONFINED MAINLY TO
THE IMMEDIATE COAST AND LOWCOUNTRY. GFS INDICATING WEAK COASTAL
SURFACE TROUGH MOVING ONSHORE LATER TODAY. SPC HRRR INDICATING
SCATTERED CONVECTION PUSHING INTO THE AREA FROM THE COAST LATER
THIS AFTERNOON. CHANCE POPS LOOK REASONABLE FOR THE AFTERNOON.
PRECIPITABLE WATER VALUES GENERALLY AT OR ABOVE 2.0 INCHES SO
LOCALLY HEAVY RAIN POSSIBLE. CONVECTION SHOULD WEAKEN DURING THE
EVENING HOURS WITH LOSS OF DAYTIME HEATING. AFTERNOON HIGHS MOSTLY
IN THE MIDDLE 80S WITH OVERNIGHT LOWS EARLY TUESDAY MORNING AROUND
70.
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
CLOSED UPPER LOW CENTERED ALONG THE GULF COAST STATES WILL CONTINUE
TO SLOWLY RETROGRADE AND FILL...WHILE WEAK UPPER RIDGING EXPANDS
OVER THE SOUTHEASTERN STATES FROM THE WESTERN ATLANTIC. THE SURFACE
PATTERN IS WEAK WITH HIGH PRESSURE CENTERED OVER VIRGINIA WEAKENING
WHILE A PERSISTENT SOUTHEASTERLY FLOW CONTINUES TO USHER MOISTURE
INLAND OFF THE ATLANTIC. PRECIPITABLE WATER VALUES WILL GRADUALLY
INCREASE TO AROUND 2 INCHES BY TUESDAY AFTERNOON AND REMAIN HIGH
THROUGH WEDNESDAY AS SOUTHERLY WINDS DEVELOP THROUGH THE LOWEST
20KFT OF THE ATMOSPHERE IN RESPONSE TO A TROUGH MOVING THROUGH THE
UPPER MISSISSIPPI AND OHIO VALLEYS.
WILL CONTINUE TO ADVERTISE HIGH CHANCE POPS ACROSS MUCH OF THE
REGION ON TUESDAY WITH THE HIGHEST POPS ACROSS THE SOUTHERN HALF OF
THE FORECAST AREA. THE THREAT OF SEVERE WEATHER APPEARS LOW WITH
PREDOMINATELY MOIST PROFILES AND WEAK SHEAR BUT HEAVY RAIN MAY BE A
CONCERN WITH STRONGER AND SLOW MOVING STORMS. SCATTERED UNORGANIZED
CONVECTION AGAIN EXPECTED ON WEDNESDAY WITH CONTINUED ELEVATED
MOISTURE PROFILES AND SLIGHTLY BETTER INSTABILITY. TEMPERATURES ON
TUESDAY AND WEDNESDAY WILL BE WARMER THAN THE PREVIOUS COUPLE OF
DAYS AND EXPECT HIGHS TO PUSH BACK INTO THE LOWER 90S WITH LOWS IN
THE LOWER 70S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
THE EXTENDED FORECAST FEATURES WHAT LOOKS LIKE AN ACTIVE WEATHER
REGIME WITH A MEAN TROUGH SETTING UP ACROSS THE EASTERN HALF OF
THE COUNTRY. AN INITIAL UPPER TROUGH WILL PUSH INTO THE REGION
FROM THE NORTHWEST ON THURSDAY RESULTING IN HEIGHT FALLS WHILE A
SURFACE TROUGH DEVELOPS OVER THE FORECAST AREA. THE SHORTWAVE
TROUGH IS FORECAST TO TRAVERSE THE FORECAST AREA THURSDAY NIGHT
INTO FRIDAY AND PUSH OFFSHORE BY FRIDAY NIGHT AS A COLD FRONT
PUSHES INTO THE AREA AND STALLS. THE FRONT WILL REMAIN STATIONARY
OVER THE REGION SATURDAY PROVIDING A FOCUS FOR PRECIPITATION AS
SOUTHWESTERLY FLOW ALOFT INCREASES IN ADVANCE OF ANOTHER SHORTWAVE
TROUGH DIGGING ACROSS THE OHIO VALLEY. THIS TROUGH WILL PUSH YET
ANOTHER FRONT INTO THE REGION BY EARLY SUNDAY AS A 1020MB SURFACE
RIDGE SETTLES ACROSS THE OHIO VALLEY INTO THE MID ATLANTIC STATES
BY SUNDAY NIGHT.
WILL CONTINUE MENTION OF SOLID CHANCE POPS THURSDAY AND FRIDAY WITH
THE FOCUS OF HIGHER POPS SHIFTING TO THE SOUTHEASTERN PART OF THE
AREA ON SATURDAY AND SUNDAY. TEMPERATURES DURING THIS PERIOD WILL
GENERALLY BE ABOVE NORMAL EARLY IN THE PERIOD AND NEAR NORMAL OVER
THE WEEKEND.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
MVFR TO POSSIBLY IFR CIGS POSSIBLE UNTIL AROUND 14Z-15Z THIS
MORNING. MODELS SHOW IMPROVEMENT AROUND MID- DAY TO EARLY
AFTERNOON WHICH ALIGNS WELL WITH THE PERSISTENCE FORECAST. ANOTHER
CHANCE FOR CONVECTION LATER THIS AFTERNOON WITH THE BEST CHANCE
SOUTH AND EAST. WILL MENTION VCSH MAINLY FOR THE AFTERNOON AND
EARLY EVENING HOURS. WINDS WILL GENERALLY BE OUT OF THE NORTHEAST
THROUGH THE PERIOD AT 10 KNOTS OR LESS.
EXTENDED AVIATION OUTLOOK...LATE NIGHT/MORNING FOG/STRATUS
POSSIBLE...WITH A CHANCE OF AFTERNOON SHOWERS AND POSSIBLE
THUNDERSTORMS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
87
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1133 AM EDT MON SEP 7 2015
...FORECAST UPDATE...
ISSUED AT 1130 AM EDT MON SEP 7 2015
THE FORECAST IS ON TRACK FOR THIS AFTERNOON...WITH MAX TEMPS
EXPECTED TO HIT THE LOW TO MID 90S. COMPARED TO 24 HOURS
AGO...READINGS ARE ABOUT 1 TO 2 DEGREES WARMER SO FEEL CONFIDENT
WE`LL HIT THE FORECAST HIGHS.
WITH WEAK SHEAR AXIS OVERHEAD...AND WEAK SHORTWAVE RETROGRADING BACK
INTO SOUTHEAST KENTUCKY...THE SLIGHT CHANCES OF SHOWERS/STORMS LOOK
GOOD. RAP SOUNDINGS ARE SHOWING WARMER MID LEVEL TEMPERATURES
COMPARED TO THE PAST FEW DAYS...WHICH SHOULD KEEP COVERAGE/INTENSITY
TO A MINIMUM.
.SHORT TERM (NOW THROUGH TUESDAY)...
ISSUED AT 235 AM EDT MON SEP 7 2015
THE SYNOPTIC PATTERN EARLY THIS MORNING FEATURES A BROAD RIDGE
ACROSS MUCH OF THE EASTERN CONUS...WITH A VERY BROAD/WEAK LOW
CONTINUING TO SPIN BENEATH THE RIDGE OVER NORTHERN GEORGIA. A SHEAR
AXIS NOTED ON THE NORTHWEST SIDE OF THIS LOW WILL BE THE MAIN FOCUS
TODAY.
LOOKING BACK TO THE CONVECTION YESTERDAY...IT WAS ALL SPARKED WITHIN
THE SHEAR AXIS BETWEEN THE UPPER LOW TO THE SOUTHEAST AND THE
AMPLIFIED RIDGE ACROSS THE GREAT LAKES/MIDWEST REGION. AREAS MAINLY
EAST OF I-65 WILL ONCE AGAIN BE WITHIN THIS SHEAR AXIS TODAY THROUGH
WHICH VERY SUBTLE UPPER-LEVEL WAVES WILL TRAVERSE AS THEY ROTATE
AROUND THE UPPER LOW. FORECAST SOUNDINGS DO SHOW WARM AIR ALOFT
MAINLY AROUND 650-700MB...BUT IT IS NOT ALL THAT MUCH STRONGER THAN
YESTERDAY WHERE WE HAD SOME ISOLATED/WIDELY SCATTERED CONVECTION.
MANY OF THE CAMS ARE ON BOARD WITH THE IDEA OF SOME VERY ISOLATED
ACTIVITY TODAY AND THESE HAVE BEEN LEADING THE CHARGE WITH
CONVECTIVE COVERAGE THE PAST FEW DAYS. THEREFORE...WILL GO WITH 15-
20% COVERAGE WITH THE BEST CHANCES EAST OF I-65 AND SOUTH OF I-64.
LOW-LEVEL THICKNESSES REMAIN VERY SIMILIAR TO WHAT THEY`VE BEEN THE
PAST FEW DAYS...SO BARRING ANY ENHANCED CLOUD COVER FROM
CONVECTION...HIGHS FIRMLY INTO THE 90S LOOK LIKELY AGAIN TODAY.
TONIGHT WILL BE MAINLY CLEAR AND MILD...WITH LOWS IN THE MID 60S TO
LOWER 70S ONCE AGAIN. ON TUESDAY...THE UPPER LOW WILL BECOME LESS
OF A PLAYER AS IT MOVES OFF TO THE SOUTHWEST. ADDITIONALLY...THE
CAPPING TOMORROW LOOKS SUBSTANTIALLY STRONGER THAN IT DOES TODAY.
THEREFORE...WILL GO WITH A DRY FORECAST AND A PERSISTENCE FORECAST
FOR HIGH TEMPERATURES.
.LONG TERM (TUESDAY NIGHT THROUGH SUNDAY)...
ISSUED AT 305 AM EDT MON SEP 7 2015
STILL LOOKING AT A TROUGH MOVING ACROSS THE REGION
WEDNESDAY/WEDNESDAY NIGHT. THE QUESTION IS HOW MUCH PRECIPITATION
WILL MOVE INTO THE REGION WEDNESDAY MORNING AHEAD OF IT. LOOKS LIKE
SOME STORMS WILL FORM OVER MO/IL EARLY WEDNESDAY AND THESE MAY PUSH
INTO OUR NORTHWEST COUNTIES AROUND DAYBREAK. THEY COULD BRING
CLOUDINESS THROUGH THE DAY...DELAYING THE ONSET OF NEW AFTERNOON
STORMS UNTIL LATER IN THE DAY AND BRINGING TEMPERATURES DOWN. SHOULD
THESE STORMS DIE OFF QUICKER THAN IN THIS FORECAST...THEN WE WOULD
SEE A LITTLE WARMER AFTERNOON HIGHS AND AN EARLIER ONSET OF STORM
DEVELOPMENT. FOR NOW WILL CALL FOR AFTERNOON HIGHS IN THE
80S...BREAKING OUR 90+ DEGREE STRING TO START SEPTEMBER. AS FOR
SEVERITY OF THESE STORMS...MODEL WIND FIELDS ARE NOT OVERLY
IMPRESSIVE. THINK THE STRONGER GUSTS WOULD COME WITH THE LATTER
SCENARIO GIVEN ABOVE. WILL CONTINUE TO MENTION BRIEF GUSTY WINDS IN
THE HWO.
ANOTHER WEAKER SHORTWAVE LOOKS TO MOVE THROUGH THE REGION
THURSDAY...CONTINUING THE CHANCE FOR RAIN...WITH THE BEST CHANCE IN
OUR SOUTHEAST. FRIDAY CONTINUES TO TREND DRIER...BUT WITH ANOTHER
WAVE CROSS ING THE REGION CANNOT RULE OUT SOME DEVELOPMENT AT LEAST
EAST OF I-65. AFTER THAT WE SHOULD BE TOO DRY FOR FURTHER
DEVELOPMENT THIS WEEKEND...AND TEMPERATURES WILL BE QUITE
PLEASANT...WITH HIGHS IN THE 70S SATURDAY AND AROUND 80 SUNDAY.
&&
.AVIATION (12Z TAF UPDATE)...
ISSUED AT 640 AM EDT MON SEP 7 2015
AFTER SOME MORNING FOG AT KBWG AND PERHAPS SOME LIGHT FOG AT
KLEX...CONDITIONS WILL RETURN TO VFR THROUGH TODAY AND INTO TONIGHT.
CAN`T RULE OUT A STRAY STORM THIS AFTERNOON MAINLY AT KLEX OR
KBWG...BUT COVERAGE WILL BE RATHER SPARSE SO WILL NOT INCLUDE ANY
MENTION IN THE FORECAST. OTHERWISE...EXPECT JUST SOME AFTERNOON CU
WITH GENERALLY LIGHT WINDS.
FOG WILL ONCE AGAIN BE POSSIBLE TONIGHT AS WE REMAIN IN A SIMILAR
PATTERN. THUS WILL INTRODUCE MVFR VSBYS ONCE AGAIN TO KBWG AND KLEX
FOR FOG NEAR SUNRISE TUESDAY.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
UPDATE.........ZBT
SHORT TERM.....KJD
LONG TERM......RJS
AVIATION.......KJD
AREA FORECAST DISCUSSION
NWS JACKSON KY
1016 AM EDT MON SEP 7 2015
.UPDATE...
ISSUED AT 1015 AM EDT MON SEP 7 2015
UPDATED THE FORECAST TO REMOVE MENTION OF FOG FROM THE TODAY
PERIOD. ALSO UPDATED THE HOURLY GRIDS WITH THE LATEST OBS DATA TO
ESTABLISH NEW TRENDS. WILL NEED TO ISSUE ANOTHER UPDATE IN A
COUPLE OF HOURS TO REMOVE WHAT WILL THEN BE OUTDATED AFTERNOON
WORDING AND ANY OTHER NECESSARY CHANGES.
UPDATE ISSUED AT 730 AM EDT MON SEP 7 2015
HOURLY GRIDS HAVE BEEN UPDATED BASED ON RECENT
OBSERVATIONS...TRENDING DOWN A DEGREE OR TWO IN A FEW VALLEY
LOCATIONS. SFC HIGH PRESSURE WILL BRING MOSTLY DRY WEATHER TO
MUCH OF THE REGION TODAY. VALLEY FOG...DENSE IN SOME
LOCATIONS...WILL DISSIPATE BY AROUND 930 AM. CUMULUS SHOULD BEGIN
TO FORM AROUND NOON AND ISOLATED CONVECTION CANNOT BE RULED OUT.
NEAR TERM MODELS SUCH AS SEVERAL RECENT HRRR RUNS DEVELOP SOME
ISOLATED CONVECTION AROUND 1 PM...MAINLY NEAR THE TN AND VA BORDER
AND ACROSS THE WESTERN PART OF THE CWA. THIS IS IN LINE WITH THE
PREVIOUS FORECAST...SO NO CHANGES WERE MADE WITH THESE.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 350 AM EDT MON SEP 7 2015
THE REGION REMAINS DOMINATED A RIDGE HIGH PRESSURE IN THE LOWER
LEVELS THAT EXTENDS FROM THE OH VALLEY INTO THE ATLANTIC...ALTHOUGH
AT MID LEVELS THE AREA CONTINUES TO RESIDE IN A WEAKNESS BETWEEN
TWO RIDGE CENTERS ONE OVER THE ATLANTIC AND ANOTHER CENTERED OVER
THE SOUTHERN PLAINS. TO THE SOUTH OF THE AREA...A WEAK UPPER LEVEL
RIDGE REMAINS. SKIES HAVE REMAINED CLEAR TO MOSTLY CLEAR OVERNIGHT
AND VALLEY FOG HAS AGAIN FORMED. IT IS LIKELY DENSE NEAR SOME OF
THE AREA RIVERS...OF SHOULD BECOME DENSE PRIOR TO DAWN.
VERY LITTLE CHANCE IS EXPECTED IN THE UPPER PATTERN IS EXPECTED
TODAY ALTHOUGH THE WEAK UPPER LEVEL LOW OVER THE SOUTHEAST SHOULD
DRIFT SOUTHWEST. SOME OF THE MODELS HAVE HEIGHTS RISING A BIT
NORTH OF THE REGION. THE SHORT TERM MODELS GENERATE SOME CONVECTION
ACROSS THE CENTRAL TO WESTERN PARTS OF THE CWA AND NEAR THE VA AND
TN BORDERS IN SOME CASES FROM AROUND MIDDAY INTO THE AFTERNOON.
SSEO CONVECTIVE PROBABILITIES REACH THE 40 TO 60 PERCENT RANGE
ACROSS THE SOUTH AND SOUTHWESTERN PARTS OF THE CWA WITH THIS AREA
EXTENDING NORTH INTO CENTRAL KY FOR THIS AFTERNOON. GIVEN THAT
THIS HAS BEEN A GOOD PREDICTOR OF AREAS OF CONVECTION THE PAST
COUPLE OF DAYS...HAVE OPTED TO GO WITH A SLIGHT CHANCE POP IN THE
AREAS THAT IT HIGHLIGHTS WITH THESE HIGHER PROBABILITIES. WARM MID
LEVEL TEMPS SHOULD LARGELY CAP CONVECTION OVER MOST OF THE
AREA...AND THE VAST MAJORITY OF THE REGION SHOULD REMAIN DRY.
TEMPERATURES SHOULD AGAIN BE ABOVE NORMAL...IN THE UPPER 80S TO
AROUND 90 RANGE OUTSIDE OF THE HIGHEST TERRAIN.
THIS EVENING THROUGH TUESDAY...SFC HIGH PRESSURE SHOULD DOMINATE
AND BE CENTERED TO THE EAST OF THE AREA. HOWEVER...THE MID AND AND
UPPER LEVEL PATTERN SHOULD BEGIN TO CHANGE. THE WEAK UPPER LOW
OVER THE SOUTHEAST SHOULD CONTINUE MEANDERING TO THE SOUTHWEST
WHILE AN UPPER LEVEL LOW MOVES FROM SASKATCHEWAN INTO MANITOBA.
TO THE SOUTH...THE UPPER LEVEL RIDGE INITIALLY CENTERED OVER THE
SOUTHERN PLAINS SHOULD BECOME CENTERED OVER THE RIO GRANDE
VALLEY/NORTHERN MEXICO WHILE A FEW SHORTWAVES MOVING AROUND THIS
RIDGE TRACK FROM THE ROCKIES AND INTO THE PLAINS. THIS WILL LEAD
TO THE BEGINNING OF HEIGHT FALLS OVER THE MID MS VALLEY NORTH INTO
THE WESTERN GREAT LAKES. THIS WILL ALLOW A FRONTAL ZONE TO MOVE
DROP SOUTHEAST INTO THE ST LAWRENCE VALLEY TO CENTRAL GREAT LAKES
TO CENTRAL PLAINS.
ON TUESDAY...THE UPPER LEVEL LOW OVER CANADA SHOULD CONTINUE
TRACKING TO THE EAST NORTHEAST WITH HEIGHTS FALLING OVER THE LOWER
OH VALLEY AS SHORTWAVES MOVE FROM THE PLAINS TOWARD THE GREAT
LAKES. AT THAT POINT...THE UPPER LOW OVER THE GULF OF MEXICO AND
SOUTHEAST SHOULD BEGIN TO MERGE WITH THE TROUGH TO THE NORTH. THE
DEEPEST MOISTURE SHOULD REMAIN TO THE SOUTH OF THE AREA...WITH THE
SOUTHERN AND SOUTHEASTERN FRINGE OF THE AREA THE MOSTLY LIKELY
AREA FOR ANY CONVECTION TO FORM. GREAT CHANCES FOR CONVECTION WILL
HOLD OFF UNTIL THE LONG TERM PERIOD.
AS ALREADY NOTED...SLIGHT CHANCE POPS WERE USED ACROSS THE FAR
WEST AND SOUTH FOR TODAY. ANY CONVECTION AND CU SHOULD DISSIPATE
DURING THE EVENING...WITH DRY WEATHER ALONG WITH SOME PATCHY DENSE
RIVER VALLEY FOG AGAIN POSSIBLE TONIGHT. THIS FOG SHOULD DISSIPATE
WITHIN AN COUPLE OF HOURS AFTER SUNRISE ON TUESDAY. SLIGHT CHANCE
POPS WERE AGAIN USED ACROSS THE FAR SOUTH AND ALONG THE VA BORDER
ON TUESDAY AS DAYTIME HEATING COULD LEAD TO CONVECTION DEVELOPING
ACROSS THAT AREA. IN SUMMARY...BOTH DAYS ARE EXPECTED TO REMAIN
DRY FOR THE VAST MAJORITY OF THE REGION.
ABOVE NORMAL TEMPERATURES SHOULD PERSIST THOUGH THE PERIOD WITH A
MINOR RIDGE/VALLEY SPLIT FOR TONIGHT.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 407 AM EDT MON SEP 7 2015
THE GENERALLY DRY PATTERN AND WARM TEMPERATURES WILL FINALLY COME
TO A END.
THE PERIOD WILL BE MET WITH RIDGING FINALLY BREAKING DOWN ACROSS
THE EAST...AS A TROUGH BEGINS TO APPROACH FROM THE MIDWEST. THAT
SAID MODELS OVERALL IN GOOD AGREEMENT THROUGH MUCH OF THE FIRST
HALF OF THE PERIOD IN TERMS OF UPPER LEVELS. HOWEVER TOWARD THE
END THE AMPLITUDE/STRENGTH OF THE TROUGH COMES INTO
QUESTION...WITH THE 07/00Z ECMWF SHOWING A CUT OFF CENTERED ACROSS
THE GREAT LAKES BY SATURDAY. RIGHT NOW CONFIDENCE REMAINS LOWER
OVERALL ON THIS GIVEN THIS IS THE FIRST RUN TO BE STRENGTHENING
THE 500MB LOW TO THAT EXTENT...AND NONE OF THE OTHER LONG RANGE
MODEL OPERATIONAL RUNS ARE IN LINE WITH THIS THOUGHT. THOUGH MIGHT
BE WORTH NOTING A FEW OF THE ENSEMBLE PERTURBATIONS SEEM TO BE
PAINTING SOMETHING SIMILAR.
AT THE SURFACE THIS PERIOD WILL BE MET WITH BETTER CHANCES OF
WIDESPREAD PRECIP AS COLD FRONT APPROACHES AND MOVES THROUGH THE
REGION. BEST CHANCES RIGHT NOW LOOK TO BE WED AND THU...WITH BEST
UPPER LEVEL SUPPORT BOTH DAYS. MORE UNCERTAINTY EXISTS WITH
SECONDARY COLD FRONT TOWARD THE END OF THE OF THE PERIOD. OVERALL
LOOKS LIKE THIS WILL BE A DRIER FRONT...BUT AFOREMENTIONED CLOSED
LOW ADVERTISED BY THE ECMWF WOULD BRING BETTER CHANCES OF PRECIP
SATURDAY. RIGHT NOW STUCK CLOSER TO THE BLEND GIVEN THE MORE
UNCERTAIN PATTERN.
THE TEMPERATURES WILL CERTAINLY BE WELCOMED WITH HIGHS NEAR TO
BELOW NORMAL. WE WILL ALSO SEE A SOME 50S FOR LOWS BY THE UPCOMING
WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 735 AM EDT MON SEP 7 2015
A RIDGE OF HIGH PRESSURE HAS BROUGHT LIGHT WINDS AND MOSTLY CLEAR
TO CLEAR SKIES OVERNIGHT...WHICH HAS SET THE STAGE FOR VALLEY
FOG. THIS FOG HAS BEEN MOST PREVALENT NEAR THE RIVERS AND LAKES.
MVFR FOG GRADUALLY LIFT OUT OF LOZ THROUGH ABOUT 13Z. AT SME...
IFR IF NOT AN INDEFINITE CEILING BELOW THE AIRPORT MIN HAS BEEN
REPORTED. OTHERWISE...SJS AND JKL HAVE BEEN FREE OF FOG WITH SYM
HAVING VIS DOWN TO 7 SM. OTHER NON TAF SITE LOCATIONS SUCH AS
EKQ...W38...1A6...AND I35 WILL INITIALLY BE DOWN TO NEAR OR BELOW
AIRPORT MINS. ALL THE FOG SHOULD LIFT AND DISSIPATE BY 13Z TO 14Z.
A DIURNALLY DRIVEN CU FIELD SHOULD DEVELOP BY AROUND 16Z. AN
ISOLATED SHRA OR TSRA WILL BE POSSIBLE NEAR LOZ AND SME...AS WELL
AS NEARER TO THE VA AND TN BORDERS. CONFIDENCE IN THIS IS TOO LOW
TO INCLUDE IN THE TAF ATTM. OUTSIDE OF ANY CONVECTION VFR SHOULD
DOMINATE FROM 13Z TO 14Z THROUGH AROUND 6Z...WHEN VALLEY FOG WILL
AGAIN FORM. LOZ AND SME MAY EXPERIENCE MVFR OR LOWER FOG AGAIN
NEAR THE END OF THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR
SHORT TERM...JP
LONG TERM...DJ
AVIATION...JP
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
737 AM EDT MON SEP 7 2015
.UPDATE...
ISSUED AT 730 AM EDT MON SEP 7 2015
HOURLY GRIDS HAVE BEEN UPDATED BASED ON RECENT
OBSERVATIONS...TRENDING DOWN A DEGREE OR TWO IN A FEW VALLEY
LOCATIONS. SFC HIGH PRESSURE WILL BRING MOSTLY DRY WEATHER TO
MUCH OF THE REGION TODAY. VALLEY FOG...DENSE IN SOME
LOCATIONS...WILL DISSIPATE BY AROUND 930 AM. CUMULUS SHOULD BEGIN
TO FORM AROUND NOON AND ISOLATED CONVECTION CANNOT BE RULED OUT.
NEAR TERM MODELS SUCH AS SEVERAL RECENT HRRR RUNS DEVELOP SOME
ISOLATED CONVECTION AROUND 1 PM...MAINLY NEAR THE TN AND VA BORDER
AND ACROSS THE WESTERN PART OF THE CWA. THIS IS IN LINE WITH THE
PREVIOUS FORECAST...SO NO CHANGES WERE MADE WITH THESE.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 350 AM EDT MON SEP 7 2015
THE REGION REMAINS DOMINATED A RIDGE HIGH PRESSURE IN THE LOWER
LEVELS THAT EXTENDS FROM THE OH VALLEY INTO THE ATLANTIC...ALTHOUGH
AT MID LEVELS THE AREA CONTINUES TO RESIDE IN A WEAKNESS BETWEEN
TWO RIDGE CENTERS ONE OVER THE ATLANTIC AND ANOTHER CENTERED OVER
THE SOUTHERN PLAINS. TO THE SOUTH OF THE AREA...A WEAK UPPER LEVEL
RIDGE REMAINS. SKIES HAVE REMAINED CLEAR TO MOSTLY CLEAR OVERNIGHT
AND VALLEY FOG HAS AGAIN FORMED. IT IS LIKELY DENSE NEAR SOME OF
THE AREA RIVERS...OF SHOULD BECOME DENSE PRIOR TO DAWN.
VERY LITTLE CHANCE IS EXPECTED IN THE UPPER PATTERN IS EXPECTED
TODAY ALTHOUGH THE WEAK UPPER LEVEL LOW OVER THE SOUTHEAST SHOULD
DRIFT SOUTHWEST. SOME OF THE MODELS HAVE HEIGHTS RISING A BIT
NORTH OF THE REGION. THE SHORT TERM MODELS GENERATE SOME CONVECTION
ACROSS THE CENTRAL TO WESTERN PARTS OF THE CWA AND NEAR THE VA AND
TN BORDERS IN SOME CASES FROM AROUND MIDDAY INTO THE AFTERNOON.
SSEO CONVECTIVE PROBABILITIES REACH THE 40 TO 60 PERCENT RANGE
ACROSS THE SOUTH AND SOUTHWESTERN PARTS OF THE CWA WITH THIS AREA
EXTENDING NORTH INTO CENTRAL KY FOR THIS AFTERNOON. GIVEN THAT
THIS HAS BEEN A GOOD PREDICTOR OF AREAS OF CONVECTION THE PAST
COUPLE OF DAYS...HAVE OPTED TO GO WITH A SLIGHT CHANCE POP IN THE
AREAS THAT IT HIGHLIGHTS WITH THESE HIGHER PROBABILITIES. WARM MID
LEVEL TEMPS SHOULD LARGELY CAP CONVECTION OVER MOST OF THE
AREA...AND THE VAST MAJORITY OF THE REGION SHOULD REMAIN DRY.
TEMPERATURES SHOULD AGAIN BE ABOVE NORMAL...IN THE UPPER 80S TO
AROUND 90 RANGE OUTSIDE OF THE HIGHEST TERRAIN.
THIS EVENING THROUGH TUESDAY...SFC HIGH PRESSURE SHOULD DOMINATE
AND BE CENTERED TO THE EAST OF THE AREA. HOWEVER...THE MID AND AND
UPPER LEVEL PATTERN SHOULD BEGIN TO CHANGE. THE WEAK UPPER LOW
OVER THE SOUTHEAST SHOULD CONTINUE MEANDERING TO THE SOUTHWEST
WHILE AN UPPER LEVEL LOW MOVES FROM SASKATCHEWAN INTO MANITOBA.
TO THE SOUTH...THE UPPER LEVEL RIDGE INITIALLY CENTERED OVER THE
SOUTHERN PLAINS SHOULD BECOME CENTERED OVER THE RIO GRANDE
VALLEY/NORTHERN MEXICO WHILE A FEW SHORTWAVES MOVING AROUND THIS
RIDGE TRACK FROM THE ROCKIES AND INTO THE PLAINS. THIS WILL LEAD
TO THE BEGINNING OF HEIGHT FALLS OVER THE MID MS VALLEY NORTH INTO
THE WESTERN GREAT LAKES. THIS WILL ALLOW A FRONTAL ZONE TO MOVE
DROP SOUTHEAST INTO THE ST LAWRENCE VALLEY TO CENTRAL GREAT LAKES
TO CENTRAL PLAINS.
ON TUESDAY...THE UPPER LEVEL LOW OVER CANADA SHOULD CONTINUE
TRACKING TO THE EAST NORTHEAST WITH HEIGHTS FALLING OVER THE LOWER
OH VALLEY AS SHORTWAVES MOVE FROM THE PLAINS TOWARD THE GREAT
LAKES. AT THAT POINT...THE UPPER LOW OVER THE GULF OF MEXICO AND
SOUTHEAST SHOULD BEGIN TO MERGE WITH THE TROUGH TO THE NORTH. THE
DEEPEST MOISTURE SHOULD REMAIN TO THE SOUTH OF THE AREA...WITH THE
SOUTHERN AND SOUTHEASTERN FRINGE OF THE AREA THE MOSTLY LIKELY
AREA FOR ANY CONVECTION TO FORM. GREAT CHANCES FOR CONVECTION WILL
HOLD OFF UNTIL THE LONG TERM PERIOD.
AS ALREADY NOTED...SLIGHT CHANCE POPS WERE USED ACROSS THE FAR
WEST AND SOUTH FOR TODAY. ANY CONVECTION AND CU SHOULD DISSIPATE
DURING THE EVENING...WITH DRY WEATHER ALONG WITH SOME PATCHY DENSE
RIVER VALLEY FOG AGAIN POSSIBLE TONIGHT. THIS FOG SHOULD DISSIPATE
WITHIN AN COUPLE OF HOURS AFTER SUNRISE ON TUESDAY. SLIGHT CHANCE
POPS WERE AGAIN USED ACROSS THE FAR SOUTH AND ALONG THE VA BORDER
ON TUESDAY AS DAYTIME HEATING COULD LEAD TO CONVECTION DEVELOPING
ACROSS THAT AREA. IN SUMMARY...BOTH DAYS ARE EXPECTED TO REMAIN
DRY FOR THE VAST MAJORITY OF THE REGION.
ABOVE NORMAL TEMPERATURES SHOULD PERSIST THOUGH THE PERIOD WITH A
MINOR RIDGE/VALLEY SPLIT FOR TONIGHT.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 407 AM EDT MON SEP 7 2015
THE GENERALLY DRY PATTERN AND WARM TEMPERATURES WILL FINALLY COME
TO A END.
THE PERIOD WILL BE MET WITH RIDGING FINALLY BREAKING DOWN ACROSS
THE EAST...AS A TROUGH BEGINS TO APPROACH FROM THE MIDWEST. THAT
SAID MODELS OVERALL IN GOOD AGREEMENT THROUGH MUCH OF THE FIRST
HALF OF THE PERIOD IN TERMS OF UPPER LEVELS. HOWEVER TOWARD THE
END THE AMPLITUDE/STRENGTH OF THE TROUGH COMES INTO
QUESTION...WITH THE 07/00Z ECMWF SHOWING A CUT OFF CENTERED ACROSS
THE GREAT LAKES BY SATURDAY. RIGHT NOW CONFIDENCE REMAINS LOWER
OVERALL ON THIS GIVEN THIS IS THE FIRST RUN TO BE STRENGTHENING
THE 500MB LOW TO THAT EXTENT...AND NONE OF THE OTHER LONG RANGE
MODEL OPERATIONAL RUNS ARE IN LINE WITH THIS THOUGHT. THOUGH MIGHT
BE WORTH NOTING A FEW OF THE ENSEMBLE PERTURBATIONS SEEM TO BE
PAINTING SOMETHING SIMILAR.
AT THE SURFACE THIS PERIOD WILL BE MET WITH BETTER CHANCES OF
WIDESPREAD PRECIP AS COLD FRONT APPROACHES AND MOVES THROUGH THE
REGION. BEST CHANCES RIGHT NOW LOOK TO BE WED AND THU...WITH BEST
UPPER LEVEL SUPPORT BOTH DAYS. MORE UNCERTAINTY EXISTS WITH
SECONDARY COLD FRONT TOWARD THE END OF THE OF THE PERIOD. OVERALL
LOOKS LIKE THIS WILL BE A DRIER FRONT...BUT AFOREMENTIONED CLOSED
LOW ADVERTISED BY THE ECMWF WOULD BRING BETTER CHANCES OF PRECIP
SATURDAY. RIGHT NOW STUCK CLOSER TO THE BLEND GIVEN THE MORE
UNCERTAIN PATTERN.
THE TEMPERATURES WILL CERTAINLY BE WELCOMED WITH HIGHS NEAR TO
BELOW NORMAL. WE WILL ALSO SEE A SOME 50S FOR LOWS BY THE UPCOMING
WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 735 AM EDT MON SEP 7 2015
A RIDGE OF HIGH PRESSURE HAS BROUGHT LIGHT WINDS AND MOSTLY CLEAR
TO CLEAR SKIES OVERNIGHT...WHICH HAS SET THE STAGE FOR VALLEY
FOG. THIS FOG HAS BEEN MOST PREVALENT NEAR THE RIVERS AND LAKES.
MVFR FOG GRADUALLY LIFT OUT OF LOZ THROUGH ABOUT 13Z. AT SME...
IFR IF NOT AN INDEFINITE CEILING BELOW THE AIRPORT MIN HAS BEEN
REPORTED. OTHERWISE...SJS AND JKL HAVE BEEN FREE OF FOG WITH SYM
HAVING VIS DOWN TO 7 SM. OTHER NON TAF SITE LOCATIONS SUCH AS
EKQ...W38...1A6...AND I35 WILL INITIALLY BE DOWN TO NEAR OR BELOW
AIRPORT MINS. ALL THE FOG SHOULD LIFT AND DISSIPATE BY 13Z TO 14Z.
A DIURNALLY DRIVEN CU FIELD SHOULD DEVELOP BY AROUND 16Z. AN
ISOLATED SHRA OR TSRA WILL BE POSSIBLE NEAR LOZ AND SME...AS WELL
AS NEARER TO THE VA AND TN BORDERS. CONFIDENCE IN THIS IS TOO LOW
TO INCLUDE IN THE TAF ATTM. OUTSIDE OF ANY CONVECTION VFR SHOULD
DOMINATE FROM 13Z TO 14Z THROUGH AROUND 6Z...WHEN VALLEY FOG WILL
AGAIN FORM. LOZ AND SME MAY EXPERIENCE MVFR OR LOWER FOG AGAIN
NEAR THE END OF THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...JP
LONG TERM...DJ
AVIATION...JP
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1142 AM EDT MON SEP 7 2015
LATEST UPDATE...
HYDRO
.SYNOPSIS...
ISSUED AT 318 AM EDT MON SEP 7 2015
THE HOLIDAY WEEKEND WILL COME TO A RATHER WET CLOSE AS A SLOW
MOVING FRONTAL SYSTEM STALLS OVER THE AREA TONIGHT INTO TUESDAY
BEFORE FINALLY CLEARING THE AREA BY MID MORNING WEDNESDAY. MOST OF
THE AREA WILL HAVE A WARM START TO THE DAY DAY WITH SOME SUNSHINE
BUT SHOWERS AND THUNDERSTORMS WILL OVERSPREAD THE AREA FROM
NORTHWEST TO SOUTHEAST BY LATE AFTERNOON. ALL AREAS WILL SEE
PERIODS OF SHOWERS AND THUNDERSTORMS TONIGHT INTO WEDNESDAY
MORNING. RAINFALL WILL BE HEAVY AT TIMES. COOLER AND DRY WEATHER
FOLLOWS LATER WEDNESDAY INTO THURSDAY. YET ANOTHER STORM COULD
MEAN A WET WEEKEND BUT THAT WILL DEPEND ON THE STORMS TRACK.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 318 AM EDT MON SEP 7 2015
MUCH HAS BEEN WRITTEN ABOUT THE RAINFALL POTENTIAL FOR TONIGHT
INTO WEDNESDAY MORNING IN ALL OF OUR DISCUSSIONS FOR AT LEAST 4
DAYS NOW AND LITTLE HAS CHANGED. EXPECT A HEAVY RAINFALL EVENT
OVER MOST OF THE AREA TONIGHT INTO WEDNESDAY MORNING. THE EXACT
AXIS OF THE HEAVIEST RAINFALL IS UNCERTAIN AT THIS TIME BUT IT
WOULD SEEM THE BEST GUESS IS CURRENTLY NORTH OF A LINE FROM SOUTH
HAVEN TO ALMA. I WOULD EXPECT SOME LOCALIZED RAINFALL AMOUNTS
COULD EXCEEDED 5 INCHES FROM THIS EVENT SO LOCALIZED FLOODING
WOULD BE AN ISSUE.
THE PRECIPITABLE WATER VALUES RISE TO NEAR 2 INCHES BY LATE
AFTERNOON OVER OUR CENTRAL CWA AND REMAIN IN PLACE UNTIL THE COLD
FRONT FINALLY CLEARS THE AREA WHEN THE SECOND UPPER WAVE MOVES
THROUGH THE AREA WEDNESDAY MORNING. THIS IS A 1 DAY IN 5 TO 10
YEAR SORT OF EVENT FOR SOUTHWEST LOWER MICHIGAN. CLEARLY SOMETHING
WE WILL NEED TO MONITOR.
THE CONVECTION OVER WISCONSIN AND LAKE MICHIGAN WILL WEAKEN SOME
AS IT MOVES INTO OUR CWA THIS MORNING BUT WILL RE-FIRE THIS
AFTERNOON AS THE DEEP MOISTURE MOVES OVERHEAD. THE FIRST PRIMARY
UPPER WAVE WILL START THE MAIN EVENT LATER TONIGHT AND THAT WILL
LAST INTO TUESDAY MORNING. THE SECOND UPPER WAVE WILL ENHANCE
ACTIVITY TUESDAY EVENING INTO WEDNESDAY MORNING.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 318 AM EDT MON SEP 7 2015
A COLD FRONT SHOULD BE JUST SOUTH OF THE CWA WEDNESDAY NIGHT AND
COOLER AIR WILL BE MOVING INTO LOWER MICHIGAN COURTESY OF A DEEP
UPPER TROUGH THAT DEVELOPS BY THE END OF THE WEEK. HIGHS IN THE 60S
ARE EXPECTED FRIDAY AND SATURDAY. THE UPPER TROUGH WILL ALSO RESULT
IN SOME SHOWERS THURSDAY NIGHT AND FRIDAY. THE ECMWF IS QUITE A BIT
DEEPER THAN THE GFS AND CLOSES OFF THE TROUGH INTO A UPPER LOW
WHEREAS THE GFS KEEPS THE SYSTEM AS AN OPEN WAVE. THE GFS SOLUTION
WOULD LIKELY RESULT IN DRIER AND WARMER CONDITONS...BUT STILL MUCH
COOLER THAN WHAT WE HAVE SEEN RECENTLY.
MODEL DIFFERENCES REALLY AFFECT THE END OF THE FORECAST. THE OPEN
WAVE ON THE GFS QUICKLY MOVES EAST ALLOWING TEMPS TO WARM UP BY
THE END OF THE WEEKEND TO AROUND 12C...WHILE THE ECMWF WOULD HOLD
ONTO H8 TEMPS NEAR 7C.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 737 AM EDT MON SEP 7 2015
CURRENTLY ALL TAF SITES ARE VFR AND FOR THE MOST PART THEY SHOULD
STAY THAT WAY THROUGH 08/06Z OR SO. THE MAIN AREA OF CONVECTION...
MOSTLY JUST SHOWER NOT THUNDERSTORMS...SHOULD MOVE INTO THE TAF
MKG AND GRR TAF SITES IN THE 06Z TO 09Z TIME FRAME. THE SHOWERS
MORE THAN LIKELY WILL NOT REACH THE OTHER TAF SITES BY 08/12Z.
IN THE VERY SHORT TERM...THE SHOWERS/THUNDERSTORMS CLOSE TO THE
MKG TAF SITE SEE WANT TO DISSIPATE BEFORE REACHING MKG. THAT ALSO
AGREES WITH OUR HIGH RESOLUTION MODELS LIKE THE RAP OR HRRR.
&&
.MARINE...
ISSUED AT 345 AM EDT MON SEP 7 2015
THE BEACH HAZARD AND SMALL CRAFT ADVISORIES HAVE BEEN
DISCONTINUED. WE MAY NEED TO REISSUE THESE PRODUCTS WEDNESDAY WHEN
THE COLD AIR COMES BACK INTO THE AREA.
&&
.HYDROLOGY...
ISSUED AT 1142 AM EDT MON SEP 7 2015
WE MAY RUN THE RISK FOR MINOR FLOODING BETWEEN LATE TONIGHT
THROUGH EARLY WEDNESDAY AS HEAVY RAIN IS POISED TO MARCH ACROSS
THE FORECAST AREA.
A SLOW MOVING FRONTAL BOUNDARY WILL BECOME NEARLY STATIONARY LATE
TONIGHT AND DURING THE DAY TUESDAY. FORECAST PRECIPITABLE WATER
VALUES OF AROUND 2.0 INCHES REMAINS UNCHANGED SINCE PRIOR
FORECASTS. TIMING SEEMS TO BE THE MOST CONSISTENT WITH THIS EVENT.
WHILE RAINFALL WILL BE POSSIBLE FROM TONIGHT THROUGH EARLY WEDNESDAY
AFTERNOON...THE HEAVIEST RAIN IS EXPECTED BETWEEN TUESDAY EVENING
AND WEDNESDAY MORNING.
THE ENTIRE FORECAST AREA CAN COUNT ON ABOUT AND INCH OF
PRECIPITATION...WHILE THE HEAVIEST SWATH LANDS NEAR AND NORTH OF
GRAND RAPIDS. 1-3 SEEMS REALISTIC ALONG AND NORTH OF I-96. THE
CATCH HERE IS THAT THE SOUTHERN HALF OF THE FORECAST AREA...SOUTH
OF I-96 REMAINS ENTRENCHED IN THE WARM SECTOR AND COULD EXPERIENCE
HIGHER INSTANTANEOUS RAINFALL RATES. THIS MEANS THAT HEAVY RAINFALL
THAT DEVELOPS IN SOUTHERN SECTIONS OF THE FORECAST AREA...MAY
RESULT IN LOCALIZED HIGHER TOTALS...4-5 INCHES.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...99
AVIATION...WDM
HYDROLOGY...JAM
MARINE...WDM
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1051 AM EDT MON SEP 7 2015
.UPDATE...
THE PROSPECTS FOR SHOWERS/THUNDERSTORMS STILL LOOKS TO BE FAIRLY
LOW/SCATTERED COVERAGE EXPECTED TODAY...AS UPPER LEVEL RIDGE (589
DAM AT 500 MB )IN PLACE IS SLOW TO FLATTEN. SURFACE COLD
FRONT/FOLDING OVER MOISTURE PLUME (PW OF 2 INCHES)/850-700 MB THETA-
E RIDGE AXIS WILL PROVIDE FOCUS FOR ACTIVITY...BUT THE FRONT IS
DISPLACED EAST OF THE UPPER LEVEL FORCING...AS 500 MB TEMPS ACTUALLY
LOOK TO RISE TOWARD -6 C TOWARD 00Z TUESDAY. MID LEVEL LAPSE RATES
(700-500 MB) WILL BE WEAK TODAY...BUT ENOUGH MLCAPE (1000-1500 J/KG)
BUILDING TO MAINTAIN THUNDERSTORM THREAT...BUT 0-6 KM BULK SHEAR
GENERALLY AROUND 20 KNOTS...DOES NOT DRAW A HUGE CONCERN FOR
SEVERE WEATHER...BUT VERY HEAVY RAINFALL IS CERTAINTY EXPECTED
WITH ANY STORM. DEEP LAYER UNIDIRECTIONAL WEST-SOUTHWEST WINDS
SHOULD KEEP CELLS MOVING JUST ENOUGH. 12Z NAM AND LATEST RUC BEING
A BIT MORE GENEROUS WITH COVERAGE OVER NORTH HALF OF THE CWA THIS
AFTERNOON...WITH LITTLE OR NO CAP IN THIS MOIST ENVIRONMENT.
HOWEVER...FORECASTED SURFACE DEW PTS LOOK TO BE A TOUCH TOO
HIGH...BUT STILL MAY DECIDE TO NUDGE POPS UP A JUST A
BIT...DEPENDING ON TREND AND FURTHER ANALYSIS.
TEMPERATURES REMAIN ON TRACK TO REACH INTO THE MID/UPPER 80S...WITH
90 DEGREES LIKELY ACROSS EASTERN AREAS...INCLUDING CITY OF DETROIT.
HIGH BASED CLOUDS SHOULD PROVIDE MODEST RELIEF...BUT CERTAINLY HOT
WITH DEW PTS IN 65 TO 70 DEGREE RANGE. INDICATIVE OF THIS HOT AND
MOIST AIRMASS...FLINT AND SAGINAW COULD SET RECORD HIGH MINIMUM
VALUES FOR TODAY (SEPTEMBER 7). SAGINAW LOW THIS MORNING WAS 73
DEGREES...WITH THE RECORD BEING 71 DEGREES SET IN 1985.
MEANWHILE...FLINT BOTTOMED OUT AT 71 DEGREES...WHICH WOULD TIE THE
RECORD HIGH MINIMUM FOR THE DATE...PREVIOUSLY SET IN 2007.
HOWEVER...STILL HAVE POTENTIAL FOR TEMPERATURES TO DROP TOWARD 70
DEGREES BY MIDNIGHT TONIGHT...ESPECIALLY WITH ANY HELP FROM RAIN
COOLED SHOWERS.
&&
.AVIATION...ISSUED 637 AM EDT MON SEP 7 2015
WIDESPREAD VFR WILL PERSIST UNTIL AT LEAST LATE TONIGHT AS THE LOWER
ATMOSPHERE REMAINS DRY. LONE EXCEPTION MAY BE MBS LATE THIS MORNING
AS SOME DEGREE OF CONVECTIVE REMNANTS ROLL THROUGH BRINGING A HEAVY
SHOWER OR TWO TO THE AIRFIELD. THIS ACTIVITY MAY REIGNITE WITH
DIURNAL HEATING /PERHAPS ALONG REMNANT OUTFLOW/ WARRANTING JUST A
TEMPO FOR HIGHER BASED SHOWERS ATTM. FORCING WILL ORGANIZE NORTH OF
THE DETROIT AREA BRINGING SHOWERS FROM KPTK NORTH BY EARLY TUESDAY
MORNING...BUT BRUNT OF ACTIVITY WILL BE FOCUSED FROM KMBS NORTH.
FOR DTW...CLOUDS MAY BE BRIEFLY SCATTERED AOB 5KFT BEFORE
LIFTING.
//DTW THRESHOLD PROBABILITIES...
* NONE
&&
.PREV DISCUSSION...ISSUED 323 AM EDT MON SEP 7 2015
SHORT TERM...TODAY AND TONIGHT
CONVECTION REMAINS FIRMLY ANCHORED TO ENHANCED SOUTHWESTERLY FLOW
ATTENDANT TO THE LEAD EDGE OF HEIGHT FALLS OVER THE WESTERN AND
NORTHERN GREAT LAKES EARLY THIS MORNING. NWP ADAMANTLY KILL THIS
ACTIVITY DURING THE EARLY MORNING, BUT THETA-E TRANSPORT HAS PROVEN
IMPRESSIVE AND CONVECTION OVER NORTHERN IL/SOUTHERN WI HAS SO FAR
BEEN RESILIENT. THE CORE OF THE LLJ AXIS WITHIN WHICH THIS ACTIVITY
IS EMBEDDED WILL GRADUALLY WEAKEN THROUGH MORNING WHICH DOES SUPPORT
EVENTUAL UPSTREAM DISSIPATION BEFORE THE LLJ FINALLY IMPINGES ON THE
FAR WESTERN CWA AFTER ABOUT 20Z. HOWEVER, DIURNAL HEATING - TEMPERED
BY CONVECTIVE DEBRIS - AND SOME DEGREE OF ONGOING MOISTURE TRANSPORT
WITHIN WEAKER SWLY FLOW OUGHT TO BE SUFFICIENT TO REGENERATE SHOWERS
ALONG THE EASTERN FRINGE OF WHAT REMAINS OF THE ENHANCED
SOUTHWESTERLIES AFTER 18Z. INDEED, PROGGED NAM12 SOUNDINGS DEPICT AN
IMPRESSIVE MOISTENING ABOVE THE LFC WHICH SHOULD HELP GET THINGS
GOING, CONDITIONAL ON SUFFICIENT BOUNDARY LAYER DEEPENING. RECENT
HRRR CYCLES SUPPORT THE IDEA OF REGENERATION AS WELL. LACK OF
INSTABILITY AND SHEAR WILL LIMIT TSTORM POTENTIAL IN GENERAL, BUT
PWATS NEAR 2 INCHES ARE A NOD TO THE PRIMARY THREAT OF HEAVY RAIN
WITH ANYTHING THAT DEVELOPS. THOUGH SENSITIVE TO CONVECTIVE
COVERAGE, HIGHS SHOULD EASILY REACH 90 ACROSS THE FAR EAST, WHILE
THICKER CLOUD COVER EARLIER IN THE DAY IS FORECAST TO LIMIT THE
SAGINAW VALLEY TO THE MID 80S.
RAPID INTENSIFYING OF THE UPPER JET OVER LAKE SUPERIOR WILL ENSUE BY
SEVERAL HOURS AFTER SUNSET MARKING THE ARRIVAL OF MORE VIGOROUS
UPPER ENERGY EMBEDDED WITHIN BROAD CYCLONIC FLOW AROUND THE MANITOBA
CYCLONE. LOWER TROPOSPHERIC FRONTAL ZONE WILL UNDERGO SUBSEQUENT
SHARPENING WHILE A SECONDARY THETA-E SURGE ORGANIZES WITHIN THE
RENEWED LLJ EMERGING OUT OF THE MIDDLE MS VALLEY. THE PRIMARY
UNCERTAINTY DURING THIS TIME IS WHETHER THIS PROCESS WILL ULTIMATELY
SUSTAIN EXISTING/LEFT OVER DIURNAL ACTIVITY OR IF DAYTIME ACTIVITY
WILL WANE COMPLETELY AND GIVE WAY TO SEVERAL HOURS OF DOWN-TIME
BEFORE ISENTROPIC ASCENT RAMPS UP AFTER MIDNIGHT. THIS WILL LIKELY
MAKE ALL THE DIFFERENCE FOR THE DETROIT METRO AREA, AS DISSIPATION
OF DIURNAL ACTIVITY WOULD LIKELY SPELL THE END OF RAIN POTENTIAL FOR
THE EVENING AS FORCING ULTIMATELY REORGANIZES ORGANIZES FURTHER
NORTH ALONG THE M59/I-69 CORRIDOR. CONFIDENCE BY EARLY TUESDAY
MORNING IS HIGHEST IN THE SAGINAW VALLEY WITHIN THE CORRIDOR OF
STRONGEST ASCENT AND DECREASES TOWARD THE THUMB. POPS ARE THEREFORE
TAPERED FROM CATEGORICAL FOR THE FORMER TO ENTRY LEVEL LIKELY FOR
THE LATTER. SKINNY CAPE PROFILE, 2+" PWATS, AND DEVELOPING 12KFT
WARM CLOUD LAYER WILL CERTAINLY SUPPORT AN ENVIRONMENT CAPABLE OF
PROLIFIC HYDROMETEOR PRODUCTION AND RESULTANT HEAVY DOWNPOURS.
ACCORDINGLY, QPF HAS BEEN RAMPED UP TO BASIN AVERAGES OF ABOUT A
HALF INCH AFTER MIDNIGHT. DEPENDING ON COVERAGE, THE POTENTIAL FOR
FURTHER UPWARD ADJUSTMENT WILL EXIST.
LOWS WILL HOVER NEAR 70 FOR YET ANOTHER NIGHT AS HIGH DEWPOINTS PUT
AN A FLOOR ON LOW TEMP POTENTIAL. SOME RELIEF ACROSS THE NORTH WILL
COME IN THE FORM OF RAINFALL, BUT SOUTHERN AREAS WILL REMAIN LARGELY
PRECIP FREE AFTER SUNSET AND WILL BE WARM AND MUGGY ONCE AGAIN.
LONG TERM...
THE LONG TERM WILL FIRST DEAL WITH A LONG DURATION RAINFALL ALONG A
STALLED FRONT...FOLLOWED BY THE INFILTRATION OF A MUCH COOLER
AIRMASS FOR THE WEEKEND.
UPPER LEVEL LOW OVER SOUTHERN CANADA WILL APPROACH WESTERN ONTARIO
TUESDAY MORNING. SEVERAL WEAK SHORTWAVES TRACKING THROUGH THE
LONGWAVE TROUGH AND HEIGHT FALLS ASSOCIATED WITH THE LOW WILL
CONTINUE TO BREAK DOWN THE RIDGE OVER THE EASTERN CONUS. THE FRONT
WILL BE DRAPED ACROSS MID MI BY TUESDAY MORNING WITH THE
PRECIPITATION EVENT WELL ON ITS WAY. A SHORTWAVE IS PROGGED TO LIFT
ALONG THE FRONT EARLY TUESDAY WHICH WILL DEVELOP A SFC LOW NEAR
IOWA. THIS WILL LIFT THE FRONT BACK NORTHWARD TEMPORARILY AS A WARM
FRONT...KEEPING THE HIGHEST POPS ACROSS THE SAGINAW VALLEY. THIS SFC
LOW WILL LIFT NE THROUGH MID MI TUESDAY EVENING WHICH WILL SIGNAL
THE START OF A MORE PROGRESSIVE SYSTEM OVERALL OWNING TO A STRONG
UPPER JET MAX COMING ASHORE BRITISH COLUMBIA MONDAY NIGHT AND
SURGING AROUND THE UPPER LOW. THIS WILL FORCE THE COLD FRONT ACROSS
LOWER MI LATE TUESDAY NIGHT INTO WEDNESDAY MORNING. THIS SYSTEM
OVERALL WILL BE A VERY EFFICIENT RAIN MAKER AS PWATS LOOK TO HOVER
JUST SHY OF 2 INCHES THROUGH THE DURATION OF THE EVENT. STEADY AND
STRONG 850MB LL JET WILL CONTINUALLY FEED MOISTURE NORTHWARD AHEAD
OF THE FRONT. IMPRESSIVE LL THETA E FIELD AS WELL WITH AN ENHANCED
RIBBON OF WARM/MOIST AIR JUST SITTING OVER THE STATE. INSTABILITY
WILL NOT BE TOO GREAT BUT A TALL SKINNY CAPE PROFILE WOULD FAVOR
HEAVY RAINFALL. POPS WILL BE DEPENDENT ON SHORTWAVE
ACTIVITY...PULSES IN THE LL JET...AND FLUCTUATIONS IN THE FRONTAL
BOUNDARY SO GENERALLY SPEAKING...LIKELYS WILL BE FEATURES ACROSS THE
NORTH WITH CHANCE POPS FURTHER SOUTH WITH FUTURE UPDATES PEGGING THE
SMALLER SCALE FORCINGS. SHOWERS WILL DOMINATE BUT SOME
ISOLATED/EMBEDDED THUNDERSTORMS CANNOT BE RULED OUT. BEST CHANCES
FOR THUNDERSTORMS WILL BE WITH THE ACTUAL FROPA WEDNESDAY MORNING.
TEMPERATURES WILL BE TRICKY TUESDAY AS THE FRONTAL LOCATION AND
EXCESSIVE CLOUDS ACROSS THE NORTH WILL LIKELY LEAD TO A HEALTHY
GRADIENT ACROSS SE MI. SHOULD STILL BE ABLE TO GET INTO THE
MID/UPPER 80S ACROSS THE SOUTH AND DETROIT METRO WITH ONGOING
SHOWERS AND CLOUDS KEEPING LOCATIONS FURTHER NORTH CLOSER TO 80 OR
EVEN IN THE UPPER 70S.
PASSAGE OF THE COLD FRONT WILL BRING ABOUT SOME NOTABLE CHANGES
FOR THE REMAINDER OF THE LONG TERM. MUCH COOLER AND DRIER AIR WILL
FEED INTO THE AREA WITH NORTHERLY FLOW. A WAVE DIVING INTO THE BASE
OF THE LONGWAVE TROUGH WILL THEN DEEPEN AND CUTOFF AS IT REACHES THE
GREAT LAKES FOR THE WEEKEND. 850MB TEMPS ARE FORECAST TO FALL BACK
INTO THE SINGLE DIGITS WITH HIGH TEMPERATURES IN THE LOW 70S...AND
POSSIBLY THE UPPER 60S FRIDAY AND SATURDAY. SHOWERS WILL BE POSSIBLE
STARTING FRIDAY NIGHT ASSOCIATED WITH THE BROAD LIFT FROM THE UPPER
LEVEL LOW AND ANY SFC PRESSURE FALLS WITH IT.
MARINE...
SOUTHWESTERLY WINDS WILL BECOME TODAY AHEAD OF AN APPROACHING FRONT.
THIS SLOW MOVING FRONT WILL BRING A CHANCE OF SHOWERS THIS MORNING
FOR NORTHERN LAKE HURON AND LATER THIS AFTERNOON FURTHER SOUTH. A
THUNDERSTORM CANNOT BE RULES OUT BUT NOT EXPECTING ANYTHING STRONG
OR WIDESPREAD. A SURFACE LOW WILL THEN TRACK THROUGH THE AREA LATE
TUESDAY...BRINGING ADDITIONAL SHOWERS AND THUNDERSTORMS THROUGH
EARLY WEDNESDAY. A PERIOD OF GUSTY SOUTHWEST WINDS WILL BE POSSIBLE
ON TUESDAY AS THIS LOW PASSES THROUGH NORTHERN LOWER MICHIGAN. THIS
WILL BE ESPECIALLY TRUE OVER SAGINAW BAY DUE TO FUNNELING.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
UPDATE.......SF
AVIATION.....JVC
SHORT TERM...JVC
LONG TERM....DRK
MARINE.......DRK
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1037 AM CDT MON SEP 7 2015
...MUCH OF THE FCST AREA UPGRADED TO A SLGT RISK OF SVR WX
TODAY...
.UPDATE...
ISSUED AT 1037 AM CDT MON SEP 7 2015
A COMPLEX SITUATION TODAY WITH POTENTIAL FOR TSTMS TO DEVELOP
OVER THE FCST AREA AS WELL AS MOVE IN FROM THE W.
PLEASE SEE THE 1252Z SPC DAY 1 OUTLOOK FOR AN EXCELLENT OVERVIEW
OF THE SITUATION.
YOU`VE PROBABLY SEEN THE UPGRADE TO A SLGT RISK. WE SAW THIS
POTENTIAL YESTERDAY AND BELIEVE IT IS WARRANTED.
ALL THE INGREDIENTS ARE THERE. OUR GREATEST CONCERN IS FROM HWY 6
DOWN INTO N-CNTRL KS IN VICINITY OF THE WARM FRONT. SHORT-TERM HI-
RES MODELS SUGGEST THE FRONT COULD LIFT BACK N INTO WEBSTER-
NUCKOLLS-THAYER COUNTIES. ANY STORMS THAT FORM ON OR NEAR THIS
FRONT WILL PROBABLY BE SUPERCELLS AND WILL NEED TO BE CLOSELY
MONITORED FOR ALL THREATS.
SKYWARN: BE ALERT FOR ACTIVATION IN THE 20Z-21Z TIME FRAME.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 AM CDT MON SEP 7 2015
MOSTLY CLEAR SKIES ARE BEING OBSERVED ACROSS THE LOCAL AREA THIS
MORNING...ALBEIT SOME LOW LEVEL STRATUS HAS BEGUN TO DEVELOP IN
SPOTS. WHILE THIS STRATUS IS PATCHY AT THE MOMENT...EXPECT THIS
STRATUS TO CONTINUE TO SPREAD IN COVERAGE THROUGH DAY BREAK...WITH
SOME LOCALLY DENSE FOG ALSO POSSIBLE THROUGH THE EARLY MORNING
HOURS. THUS FAR...FOG HAS NOT BEEN ABLE TO DEVELOP...BUT WITH DEW
POINT DEPRESSIONS CONTINUING TO SHRINK AND A FEW TEMPS NOW
REACHING THEIR ASSOCIATED DEWPOINT VALUES...CONTINUE TO THINK THE
LATEST HRRR MIGHT BE CORRECT WITH AT LEAST SOME PATCHY DENSE FOG
DEVELOPING AROUND SUNRISE. AS A RESULT...CONTINUED TO MAINTAIN THE
LOWER VISIBILITY WORDING FOR THE MORNING HOURS OF THE FORECAST AND
WILL ALSO CONTINUE TO ADVERTISE IN THE HWO.
WITH SOME CONVECTION ALREADY FORMING ACROSS THE HIGH PLAINS...AND
FAVORABLE UPPER LEVEL JET DYNAMICS EXPECT BY MID AFTERNOON...
EXPECT SOME SHOWERS AND THUNDERSTORMS TO DEVELOP AND MOVE ACROSS
THE REGION...GENERALLY FAVORING AREAS ACROSS SOUTH CENTRAL
NEBRASKA. MODEL SOUNDINGS ARE INDICATIVE OF AMPLE CAPE ACROSS THE
REGION...AND THIS INSTABILITY COMBINED WITH 0-6KM SHEAR VALUES
UPWARDS OF 50KTS EXPECTED LATER IN THE DAY...WOULD NOT BE
SURPRISED TO SEE A FEW STRONG AND ORGANIZED THUNDERSTORMS DEVELOP
ACROSS THE LOCAL AREA. LATEST CONVECTIVE OUTLOOK FROM SPC IS
INDICATIVE OF THIS...WITH THE ENTIRE AREA RIGHT IN THE MIDDLE OF A
MARGINAL RISK FOR SEVERE WEATHER THIS AFTERNOON. AS WITH YESTERDAY
...WHILE THE OVERALL TORNADO THREAT IS FAIRLY LOW...A 2 PERCENT
TORNADO RISK IS IN THE LATEST OUTLOOK...AND WILL ADD THIS MENTION
TO THE HWO DESPITE LARGE HAIL AND THUNDERSTORM WIND GUSTS BEING
THE PRIMARY CONCERNS.
TEMPERATURE WISE...EXPECT MOST AREAS TO STRUGGLE TO REACH OR
SLIGHTLY EXCEED 80 DEGREES THIS AFTERNOON...WHICH WILL BE A NICE
CHANCE FOR MOST FOLKS. ONCE SKIES CLEAR AND RAINFALL CHANCES
DIMINISH SOME OVERNIGHT...EXPECT A SEASONABLY COOL START TO
TUESDAY FOR THE LOCAL AREA...WITH NEAR TO SLIGHTLY ABOVE SEASONAL
NORMS FOR LOW TEMPERATURES...WITH FORECAST LOWS GENERALLY FALLING
INTO THE UPPER 50S ACROSS OUR NORTH...AND INTO THE LOWER TO MIDDLE
60S ACROSS NORTH CENTRAL KANSAS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 405 AM CDT MON SEP 7 2015
PRIMARY FORECAST CONCERN THROUGH THE LONG TERM LIES WITH
PRECIPITATION CHANCES.
THE START OF THE PERIOD SHOWS MODELS NOT IN TOO BAD OF AGREEMENT
WITH THE OVERALL UPPER LEVEL PATTERN...WITH THE CWA UNDER ZONAL TO
SLIGHTLY SWRLY FLOW...THANKS TO BROAD TROUGHING CONNECTED TO A LOW
PRESSURE SYSTEM LOCATED OVER NORTH CENTRAL CANADA. AT THE SFC...
STILL EXPECTING THERE TO BE A FRONTAL BOUNDARY MEANDERING AROUND
THE AREA...THOUGH EXACT PLACEMENT IS UNCERTAIN AS IT WILL LIKELY
BE AFFECTED BY ANY THUNDERSTORMS MOVING THROUGH TONIGHT. CONTINUE
TO HAVE POPS RIGHT OFF THE BAT TUESDAY MORNING...LINGERING
ACTIVITY FROM TONIGHT...WHICH IS EXPECTED TO BE SLIDING OFF TO THE
EAST WITH A GRADUALLY VEERING/WANING LLJ. THINKING IS THAT THERE
WILL BE AT LEAST A BIT OF A BREAK IN ACTIVITY LATER IN THE MORNING
PERHAPS INTO THE EARLY AFTERNOON HOURS...BUT ANOTHER LOBE OF
SHORTWAVE ENERGY ASSOCIATED WITH THAT UPPER LEVEL CANADIAN LOW IS
EXPECTED TO MOVE INTO THE AREA FROM THE NW LATE IN THE
AFTERNOON...PROVIDING THE OPPORTUNITY FOR ADDITIONAL
THUNDERSTORMS. WHILE KEPT POPS IN PLACE CWA-WIDE DURING THE
AFTERNOON...HAVE 30-40 POPS GOING ACROSS THE SERN PORTIONS OF THE
CWA...CLOSER TO THE MAIN SFC FRONT WHICH LOOKS TO EXTEND FROM EAST
CENTRAL TO SOUTH CENTRAL PORTIONS OF KS BY TUES EVENING. HAVE SOME
LINGERING 20 POPS DURING THE EVENING HOURS...BUT KEPT THE FORECAST
DRY POST-06Z AS THINGS GET PUSHED FURTHER S/SE. CONFIDENCE IN
TEMPS FOR TUESDAY IS NOT HIGH...AND WILL BE GREATLY AFFECTED BY
LINGERING PRECIP/CLOUDS AS WELL AS THE ULTIMATE LOCATION OF THE
SFC BOUNDARY. AT THIS POINT...HIGHS ARE FORECAST TO REACH THE
UPPER 70S TO LOWER 80S.
THE FORECAST FOR WED IS A DRY ONE...WITH THE TUES SYSTEM EXPECTED
TO PUSH OFF TO THE EAST...LEAVING MORE NWRLY /BUT STILL LOW
AMPLITUDE/ UPPER LEVEL FLOW IN ITS WAKE. A WEAK SFC PATTERN AND
LIGHT WINDS TO START THE DAY IS EXPECTED TO GIVE WAY TO MORE
SOUTHERLY WINDS WITH TIME...AS SFC LOW PRESSURE BECOMES BETTER
ORGANIZED TO OUR WEST AHEAD OF THE NEXT UPPER LEVEL SYSTEM
APPROACHING THE REGION FROM THE NW. THE LACK OF A NOTABLE CHANGE
IN AIR MASS BEHIND THE EARLY WEEK FRONT LOOKS TO KEEP HIGH TEMPS
FOR WED IN THE UPPER 70S/LOWER 80S.
LOOKING AT THE WED NIGHT THROUGH EARLY SAT PERIOD...CONFIDENCE IN
THE FORECAST IS NOT HIGH...AS PLENTY OF DIFFERENCES BETWEEN MODELS
REMAIN. THE LATEST RUN OF THE GFS SHOWS THE POSSIBILITY OF A
COUPLE OF SHORTWAVE DISTURBANCES MOVING THROUGH DURING THIS TIME
FRAME...WHILE THE ECMWF SHOWS A MORE ORGANIZED CLOSED LOW
DEVELOPING BY THURS EVENING OVER THE WRN GREAT LAKES AND PUSHING
OFF TO THE EAST. ONE OF THE RESULTING DIFFERENCES IS THE GFS WOULD
BRING A COUPLE OF SHOTS AT PRECIP...VS THE LIKELY JUST ONE SHOT
VIA THE ECMWF. HAD INHERITED A FEW PERIODS OF POPS IN THIS TIME
FRAME...AND WITH THE GFS STILL SUPPORTING THAT WILL KEEP IT
GOING...BUT IF THINGS TREND TOWARD THE 00Z ECMWF...SOME OF THOSE
PERIOD WOULD NEED TO HAVE POPS REMOVED. WE SHALL SEE. BOTH
SOLUTIONS SHOW ANOTHER SFC COLD FRONT MOVING THROUGH THE
REGION...WITH THE ECMWF SHOWING A BETTER PUSH OF COOLER AIR THAN
THE GFS AT THIS POINT. FORECAST HIGHS REMAIN A BLEND THURS-
SAT...DROPPING BACK INTO THE 70S CWA-WIDE.
BETTER AGREEMENT KEEPING SUN DRY...WITH HIGHS REBOUNDING BACK
INTO THE 80S FOR MAINLY THE SWRN THIRD OR SO OF THE CWA.
&&
.AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z TUE MORNING)
ISSUED AT 550 AM CDT MON SEP 7 2015
LOW LEVEL STRATUS HAS MOVED IN ACROSS THE AREA WITH IFR CIGS NOW
BEING OBSERVED AT BOTH TERMINALS. WITH THIS LOW STRATUS...MAY NOT
SEE VSBYS DROP AS LOW AS PREVIOUSLY THOUGH...BUT WITH A FEW SITES
SHOWING IFR VSBYS...OPTED TO INCLUDE THE MENTION OF BR FOR SEVERAL
HOURS THIS MORNING. OTHERWISE...EXPECT THE STRATUS TO BE SLOW TO
BURN OFF BY LATE MORNING...WITH INCREASING CHANCES FOR
THUNDERSTORMS THEREAFTER. OUTSIDE OF ANY THUNDERSTORM ACTIVITY...
WINDS ARE EXPECTED TO REMAIN FAIRLY LIGHT TODAY...GENERALLY OUT
OF THE EAST OR NORTHEAST AT 10 MPH OR LESS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...ROSSI
LONG TERM...ADP
AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
642 AM CDT MON SEP 7 2015
.SYNOPSIS...
ISSUED AT 356 AM CDT MON SEP 7 2015
LARGE UPPER LOW LOCATED OVER SRN CANADA WITH TROUGH AXIS SWD INTO
MT AND ID...WITH NOTABLE PV ANOMALY MOVING THROUGH THE BASE OF
THE TROUGH OVER NRN NV. ZONE OF HIGHER SWRLY FLOW ALOFT LOCATED
AHEAD OF THIS UPPER TROUGH FROM MN TO SRN CA...RUNNING THROUGH
THE NWRN CORNER OF NEB. ALONG THIS SWRLY FLOW ALOFT...WEAK SHORT
WAVES CONTINUE TO PROGRESS QUICKLY NEWD AS THEY HAVE THE PAST FEW
DAYS. SFC FRONT THAT MOVED THROUGH THE AREA THIS MORNING LOCATED
FROM SRN IA ACROSS NERN KS SWWD TO NEAR DDC. THIS FRONT MARKED BY
CONVECTION FROM SRN IA INTO NERN KS. ON THE NORTH SIDE OF THIS
FRONT...ERLY UPSLOPE FLOW EXISTS AT THE SFC WITH NERLY WIND AT
500M/1KM AT KLNX. SFC WINDS HAVE TURNED SERLY ALREADY FROM THE
PANHANDLE INTO NWRN KS AND THIS IS CONTRIBUTING TO TSRA
DEVELOPMENT ACROSS WRN NEB. VSBYS STARTING TO BE REDUCED IN THE
ONL AREA DUE TO FOG.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 356 AM CDT MON SEP 7 2015
FOR THIS MORNING...TSRA DEVELOPING AND MOVING EWD ALONG GRADIENT
OF STEEPER LAPSE RATES ALOFT AND WILL LIKELY BE SUSTAINED AS
ELEVATED INSTABILITY EXPANDS EWD IN INCREASING ISENTROPIC
UPGLIDE. CIRA LOW CLOUD/FOG PRODUCT SHOWING ONLY LIMITED
DEVELOPMENT OF LOW CLOUDS AS EXPECTED BY SHORT RANGE MODELS AND
SREF PROBABILITY GUIDANCE. WILL CONTINUE THE IDEA OF PATCHY FOG
THOUGH CONVECTIVE TRENDS SO FAR WOULD SUGGEST FURTHER FOG
DEVELOPMENT MAY BE INHIBITED SOMEWHAT.
PREVIOUSLY MENTIONED PV ANOMALY OVER NRN NV WILL CONTINUE TO
ROTATE NEWD TODAY AND AS THE ENTIRE TROUGH PULLS EWD...UPPER
LEVEL JET DEVELOPMENT OCCURS IN CONFLUENT ZONE OVER WY TODAY.
THIS WILL PUT THE RIGHT ENTRANCE REGION OF THE NEWLY DEVELOP JET
STREAK OVER WRN NEB BY AFTERNOON. THE RESULTING DIRECT THERMAL
CIRCULATION THAT IS ALREADY DEVELOPING IN RESPONSE OVER THE HIGH
PLAINS...AS EVIDENCED BY ISENTROPIC LIFT ON THE 310/315K
SFC...WILL INDUCE A NWRLY LOW LEVEL AGEOSTROPHIC FLOW AND ENHANCE
FRONTOGENSIS ACROSS THE WRN PORTION OF THE AREA THIS AFTERNOON.
AS THIS OCCURS IN A REGION OF DECENT MID LEVEL INSTABILITY...NEW
TSRA SHOULD DEVELOP THIS AFTERNOON IN WRN NEB AND MOVE EWD. CAPE
IS NOT EXTREME BUT WITH GOOD SHEAR IN PLACE THROUGH A DEEP LAYER
SOME POTENTIAL FOR LARGE HAIL WILL EXIST WITH ANY STORMS THAT DO
DEVELOP...HENCE THE MARGINAL RISK AS DEPICTED BY SPC. THE FLY IN
THE OINTMENT HERE WOULD BE ONGOING CONVECTION AND CONVECTIVE
DEBRIS THAT REMAIN FROM THIS MORNINGS CONVECTION AND HOW THAT
AFFECTS THE ATMOSPHERE BY THIS AFTERNOON. CLOUD COVER MAY
NEGATIVELY AFFECT THE STORMS BEING ABLE TO REALIZE AVAILABLE
CAPE...BUT LEFT OVER BOUNDARIES MAY BE A FOCUS FOR UPWARD
VERTICAL MOTION ENHANCEMENT TO POSITIVELY INFLUENCE INDIVIDUAL
UPDRAFTS...SO ANOTHER COMPLICATED FCST REMAINS. SHORT RANGE
MODELS AND CAM ENSEMBLES AGAIN SUGGEST A WIDE RANGE OF POSSIBLE
SOLUTIONS. ALTHOUGH THE HRRR HAS HAD ITS STRUGGLES LATELY...THINK
IT MIGHT BE ON TO THE RIGHT IDEA DEVELOPING TSRA IN THE 3-4PM CDT
TIME RANGE. THIS IDEA IS ALSO SUPPORTED BY THE NSSL WRF AND BY A
FEW MEMBERS OF THE NCAR 10 MEMBER 3KM WRF ENSEMBLE. THE POPS FCST
IS THEREFORE LIMITED TO THE CHC RANGE FOR NOW.
FOG/LOW CLOUDS MAY BE POSSIBLE AGAIN TONIGHT AND IS SHOWN IN SOME
OF THE MOS GUIDANCE AS WELL AS THE 07.03Z SREF. ULTIMATE
DEVELOPMENT HOWEVER WILL DEPEND ON THE CONVECTIVE TRENDS
OVERNIGHT...SO CONFIDENCE WAS NOT HIGH ENOUGH TO INCLUDE IN THE
FCST AT THIS POINT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 356 AM CDT MON SEP 7 2015
CHILLY TUESDAY WITH LINGERING MORNING SHOWERS GIVING WAY TO
PARTLY SUNNY SKIES. COOL HIGH PRESSURE BUILDS ACROSS THE AREA AND
BATTLE BETWEEN CAA AND SEPTEMBER SUN. THE BIGGEST THING TO WATCH
IS HOW SOON CLOUDS DISSIPATE...WHICH WILL HAVE A DIRECT IMPACT ON
HIGHS. MOST AREAS HOLD IN THE 70S...EXCEPT FOR FAR SW WITH HIGHS
AROUND 80...ALTHOUGH AN EARLIER CLEARING WILL BUMP UP TEMPS A
GOOD 5 DEGREES OR MORE.
BL MOISTURE WILL BE A CONCERN TUESDAY NIGHT INTO WED MORN. THE
NAM WHICH HAS MORE BL MOISTURE SUGGESTS STRATUS/FOG COULD DEVELOP
WITH WINDS BECOMING SOUTHEASTERLY/SOUTHERLY ON THE BACK SIDE OF
THE SFC HIGH. THE GFS/EC MOS GUIDANCE IS DRIER AND KEEPS THINGS
CLEAR AND HAS SLIGHTLY LOWER TEMPS. MODELS HAVE BEEN STRUGGLING
WITH LOW LEVEL MOISTURE...WHICH LEADS TO LOW CONFIDENCE IN
WHETHER FOG/STRATUS WILL DEVELOP OR NOT.
WEDNESDAY WILL SEE THE NEXT WEAK COLD FRONT PUSH ACROSS THE AREA.
SLIGHT WARM UP AHEAD OF THE FRONT WITH MOST HIGHS AROUND 80 INTO
THE MID 80S. MODELS HAVE BEEN IN GOOD AGREEMENT DEVELOPING A LINE
OF STORMS ALONG THE BOUNDARY WHICH MODEL BLENDS PLACE ACROSS THE
HEART /FROM NORTHEAST TO SOUTHWEST/ OF THE CWA DURING PEAK
HEAT/INITIATION. SHEAR IS WEAK HOWEVER A NARROW BAND WITH CAPE
VALUES OF 500 TO 1000 J/KG SO EXPECT AT LEAST SOME ISOLD THUNDER.
HIGH PRESSURE BRINGS DRY AIR FOR THURSDAY. HIGH QUICKLY MOVES
EAST FOR FRIDAY WITH RETURN SOUTHERLY FLOW TO BRING AN INCREASE
OF MOISTURE. SOME AFTERNOON INSTABILITY DEVELOPS THEN A LL JET
KICKS IN OVERNIGHT. RESULTS IN AT LEAST A SLGHT CHANCE FOR
PRECIP FRIDAY INTO FRIDAY NIGHT. INBETWEEN SYSTEMS FOR THE
WEEKEND WITH SEASONAL AND DRY CONDITIONS EXPECTED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 642 AM CDT MON SEP 7 2015
VERY DIFFICULT AVIATION FCST FOR THE NEXT 24 HRS. CIRA LOW
CLOUD/VIS PRODUCT SHOWING THE LOWER CLOUDS ACROSS PORTIONS OF
CENTRAL INTO SW NEB...AND OBS/AREA WEB CAMS SHOWING REDUCTIONS IN
VSBY AROUND O`NEILL SWWD TO NEAR BBW. CIGS ARE IFR IN THE ERN
AREAS AS WELL WITH MVFR IN THE SW. AC AND SCT SHRA MOVING NEWD
ATOP THESE LOWER CLOUDS IN AN AREA OF ELEVATED INSTABILITY.
OPERATIONAL HRRR SUGGESTING THESE WILL MOVE OUT BUT NEW
DEVELOPMENT NEAR KLBF BY LATE MORNING WOULD OCCUR...AND THIS
BACKED UP WITH RAP AND A FEW WRF VERSIONS. HAVE THEREFORE INCLUDED
SEVERAL ROUNDS OF PRECIP IN OR NEAR THE KLBF TAF SITE TODAY. FCST
SOUNDINGS SHOW LOW CLOUDS AND LOW VSBYS /IFR CONDITIONS/ WOULD
STAY EAST OF KVTN TODAY...BUT OVERALL CONFIDENCE IN THIS FCST IS
LOW. TIMING OF SUBSEQUENT TSRA WITH FRONT THIS AFTERNOON AND
EVENING IS DEPENDANT ON SEVERAL FACTORS INCLUDING HOW MUCH
SUNSHINE WILL OCCUR POST MORNING CONVECTION.
AFTER NEXT FRONT MOVES THROUGH TONIGHT AND ESSENTIALLY WASHES OUT
COULD SEE ANOTHER ROUND OF LOW CLOUDS TONIGHT...BUT AGAIN
CONFIDENCE IN THIS SOLUTIONS IS LOW AT THIS POINT AND HAVE
THEREFORE NOT INCLUDED IT.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JWS
SHORT TERM...JWS
LONG TERM...MASEK
AVIATION...JWS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
622 AM CDT MON SEP 7 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 AM CDT MON SEP 7 2015
MOSTLY CLEAR SKIES ARE BEING OBSERVED ACROSS THE LOCAL AREA THIS
MORNING...ALBEIT SOME LOW LEVEL STRATUS HAS BEGUN TO DEVELOP IN
SPOTS. WHILE THIS STRATUS IS PATCHY AT THE MOMENT...EXPECT THIS
STRATUS TO CONTINUE TO SPREAD IN COVERAGE THROUGH DAY BREAK...WITH
SOME LOCALLY DENSE FOG ALSO POSSIBLE THROUGH THE EARLY MORNING
HOURS. THUS FAR...FOG HAS NOT BEEN ABLE TO DEVELOP...BUT WITH DEW
POINT DEPRESSIONS CONTINUING TO SHRINK AND A FEW TEMPS NOW
REACHING THEIR ASSOCIATED DEWPOINT VALUES...CONTINUE TO THINK THE
LATEST HRRR MIGHT BE CORRECT WITH AT LEAST SOME PATCHY DENSE FOG
DEVELOPING AROUND SUNRISE. AS A RESULT...CONTINUED TO MAINTAIN THE
LOWER VISIBILITY WORDING FOR THE MORNING HOURS OF THE FORECAST
AND WILL ALSO CONTINUE TO ADVERTISE IN THE HWO.
WITH SOME CONVECTION ALREADY FORMING ACROSS THE HIGH PLAINS...AND
FAVORABLE UPPER LEVEL JET DYNAMICS EXPECT BY MID
AFTERNOON...EXPECT SOME SHOWERS AND THUNDERSTORMS TO DEVELOP AND
MOVE ACROSS THE REGION...GENERALLY FAVORING AREAS ACROSS SOUTH
CENTRAL NEBRASKA. MODEL SOUNDINGS ARE INDICATIVE OF AMPLE CAPE
ACROSS THE REGION...AND THIS INSTABILITY COMBINED WITH 0-6KM SHEAR
VALUES UPWARDS OF 50KTS EXPECTED LATER IN THE DAY...WOULD NOT BE
SURPRISED TO SEE A FEW STRONG AND ORGANIZED THUNDERSTORMS DEVELOP
ACROSS THE LOCAL AREA. LATEST CONVECTIVE OUTLOOK FROM SPC IS
INDICATIVE OF THIS...WITH THE ENTIRE AREA RIGHT IN THE MIDDLE OF A
MARGINAL RISK FOR SEVERE WEATHER THIS AFTERNOON. AS WITH
YESTERDAY...WHILE THE OVERALL TORNADO THREAT IS FAIRLY LOW...A 2
PERCENT TORNADO RISK IS IN THE LATEST OUTLOOK...AND WILL ADD THIS
MENTION TO THE HWO DESPITE LARGE HAIL AND THUNDERSTORM WIND GUSTS
BEING THE PRIMARY CONCERNS.
TEMPERATURE WISE...EXPECT MOST AREAS TO STRUGGLE TO REACH OR
SLIGHTLY EXCEED 80 DEGREES THIS AFTERNOON...WHICH WILL BE A NICE
CHANCE FOR MOST FOLKS. ONCE SKIES CLEAR AND RAINFALL CHANCES
DIMINISH SOME OVERNIGHT...EXPECT A SEASONABLY COOL START TO
TUESDAY FOR THE LOCAL AREA...WITH NEAR TO SLIGHTLY ABOVE SEASONAL
NORMS FOR LOW TEMPERATURES...WITH FORECAST LOWS GENERALLY FALLING
INTO THE UPPER 50S ACROSS OUR NORTH...AND INTO THE LOWER TO MIDDLE
60S ACROSS NORTH CENTRAL KANSAS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 405 AM CDT MON SEP 7 2015
PRIMARY FORECAST CONCERN THROUGH THE LONG TERM LIES WITH
PRECIPITATION CHANCES.
THE START OF THE PERIOD SHOWS MODELS NOT IN TOO BAD OF AGREEMENT
WITH THE OVERALL UPPER LEVEL PATTERN...WITH THE CWA UNDER ZONAL TO
SLIGHTLY SWRLY FLOW...THANKS TO BROAD TROUGHING CONNECTED TO A LOW
PRESSURE SYSTEM LOCATED OVER NORTH CENTRAL CANADA. AT THE
SFC...STILL EXPECTING THERE TO BE A FRONTAL BOUNDARY MEANDERING
AROUND THE AREA...THOUGH EXACT PLACEMENT IS UNCERTAIN AS IT WILL
LIKELY BE AFFECTED BY ANY THUNDERSTORMS MOVING THROUGH TONIGHT.
CONTINUE TO HAVE POPS RIGHT OFF THE BAT TUESDAY MORNING...LINGERING
ACTIVITY FROM TONIGHT...WHICH IS EXPECTED TO BE SLIDING OFF TO THE
EAST WITH A GRADUALLY VEERING/WANING LLJ. THINKING IS THAT THERE
WILL BE AT LEAST A BIT OF A BREAK IN ACTIVITY LATER IN THE MORNING
PERHAPS INTO THE EARLY AFTERNOON HOURS...BUT ANOTHER LOBE OF
SHORTWAVE ENERGY ASSOCIATED WITH THAT UPPER LEVEL CANADIAN LOW IS
EXPECTED TO MOVE INTO THE AREA FROM THE NW LATE IN THE
AFTERNOON...PROVIDING THE OPPORTUNITY FOR ADDITIONAL THUNDERSTORMS.
WHILE KEPT POPS IN PLACE CWA-WIDE DURING THE AFTERNOON...HAVE 30-40
POPS GOING ACROSS THE SERN PORTIONS OF THE CWA...CLOSER TO THE MAIN
SFC FRONT WHICH LOOKS TO EXTEND FROM EAST CENTRAL TO SOUTH CENTRAL
PORTIONS OF KS BY TUES EVENING. HAVE SOME LINGERING 20 POPS DURING
THE EVENING HOURS...BUT KEPT THE FORECAST DRY POST-06Z AS THINGS GET
PUSHED FURTHER S/SE. CONFIDENCE IN TEMPS FOR TUESDAY IS NOT
HIGH...AND WILL BE GREATLY AFFECTED BY LINGERING PRECIP/CLOUDS AS
WELL AS THE ULTIMATE LOCATION OF THE SFC BOUNDARY. AT THIS
POINT...HIGHS ARE FORECAST TO REACH THE UPPER 70S TO LOWER 80S.
THE FORECAST FOR WED IS A DRY ONE...WITH THE TUES SYSTEM EXPECTED TO
PUSH OFF TO THE EAST...LEAVING MORE NWRLY /BUT STILL LOW AMPLITUDE/
UPPER LEVEL FLOW IN ITS WAKE. A WEAK SFC PATTERN AND LIGHT WINDS TO
START THE DAY IS EXPECTED TO GIVE WAY TO MORE SOUTHERLY WINDS WITH
TIME...AS SFC LOW PRESSURE BECOMES BETTER ORGANIZED TO OUR WEST
AHEAD OF THE NEXT UPPER LEVEL SYSTEM APPROACHING THE REGION FROM THE
NW. THE LACK OF A NOTABLE CHANGE IN AIR MASS BEHIND THE EARLY WEEK
FRONT LOOKS TO KEEP HIGH TEMPS FOR WED IN THE UPPER 70S/LOWER 80S.
LOOKING AT THE WED NIGHT THROUGH EARLY SAT PERIOD...CONFIDENCE IN
THE FORECAST IS NOT HIGH...AS PLENTY OF DIFFERENCES BETWEEN MODELS
REMAIN. THE LATEST RUN OF THE GFS SHOWS THE POSSIBILITY OF A COUPLE
OF SHORTWAVE DISTURBANCES MOVING THROUGH DURING THIS TIME
FRAME...WHILE THE ECMWF SHOWS A MORE ORGANIZED CLOSED LOW DEVELOPING
BY THURS EVENING OVER THE WRN GREAT LAKES AND PUSHING OFF TO THE
EAST. ONE OF THE RESULTING DIFFERENCES IS THE GFS WOULD BRING A
COUPLE OF SHOTS AT PRECIP...VS THE LIKELY JUST ONE SHOT VIA THE
ECMWF. HAD INHERITED A FEW PERIODS OF POPS IN THIS TIME FRAME...AND
WITH THE GFS STILL SUPPORTING THAT WILL KEEP IT GOING...BUT IF
THINGS TREND TOWARD THE 00Z ECMWF...SOME OF THOSE PERIOD WOULD NEED
TO HAVE POPS REMOVED. WE SHALL SEE. BOTH SOLUTIONS SHOW ANOTHER SFC
COLD FRONT MOVING THROUGH THE REGION...WITH THE ECMWF SHOWING A
BETTER PUSH OF COOLER AIR THAN THE GFS AT THIS POINT. FORECAST HIGHS
REMAIN A BLEND THURS-SAT...DROPPING BACK INTO THE 70S CWA-WIDE.
BETTER AGREEMENT KEEPING SUN DRY...WITH HIGHS REBOUNDING BACK INTO
THE 80S FOR MAINLY THE SWRN THIRD OR SO OF THE CWA.
&&
.AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 550 AM CDT MON SEP 7 2015
LOW LEVEL STRATUS HAS MOVED IN ACROSS THE AREA WITH IFR CIGS
NOW BEING OBSERVED AT BOTH TERMINALS. WITH THIS LOW STRATUS...MAY
NOT SEE VSBYS DROP AS LOW AS PREVIOUSLY THOUGH...BUT WITH A FEW
SITES SHOWING IFR VSBYS...OPTED TO INCLUDE THE MENTION OF BR FOR
SEVERAL HOURS THIS MORNING. OTHERWISE...EXPECT THE STRATUS TO BE
SLOW TO BURN OFF BY LATE MORNING...WITH INCREASING CHANCES FOR
THUNDERSTORMS THEREAFTER. OUTSIDE OF ANY THUNDERSTORM
ACTIVITY...WINDS ARE EXPECTED TO REMAIN FAIRLY LIGHT
TODAY...GENERALLY OUT OF THE EAST OR NORTHEAST AT 10 MPH OR LESS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...ROSSI
LONG TERM...ADP
AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
934 AM CDT MON SEP 7 2015
.UPDATE...
ISSUED AT 934 AM CDT MON SEP 7 2015
TWEAKED POPS TO INCLUDE THE SHOWERS MOVING INTO THE VALLEY CITY
AREA. NOT MUCH IS REACHING THE GROUND...BUT RETURNS ARE STRONG
ENOUGH AS A SHORTWAVE MOVES UP FROM SOUTH DAKOTA TO INCLUDE A
SMALL CHANCE FOR RAIN THROUGHOUT THIS AFTERNOON. OVERALL KEPT THE
TREND OF INCREASING CLOUDS AND HIGHS TOPPING OUT IN THE 60S TO MID
70S.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 348 AM CDT MON SEP 7 2015
THE MAIN CHALLENGE THIS PERIOD WILL BE SHOWER CHANCES AND
TEMPERATURES. THE AIRMASS CHANGE HAS OCCURRED WITH MUCH COOLER
AND DRIER ADVECTING INTO THE REGION. UPPER LOW WILL SLOWLY
PROPAGATE EAST ACROSS CANADA...AND MOST MODEL GUIDANCE SUGGESTS A
WAVE WITHIN THIS FLOW PATTERN WILL LEAD TO SHOWERS THIS AFTERNOON.
GIVEN THE DRY AIRMASS IN PLACE ANY RADAR RETURNS WILL LIKELY
APPEAR WORSE THAN WHAT IS OCCURRING AT THE GROUND...BUT DID
INCLUDE ISOLD SHOWERS AS HRRR INDICATES WEAK BANDING POTENTIAL.
ANTICIPATE SOLAR TODAY...WHICH SHOULD ALLOW MAX TEMPS INTO THE
70S.
DRY ON TUESDAY...AND SLIGHTLY COOLER AS THE UPPER LOW IN CANADA
SHIFTS EAST.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 348 AM CDT MON SEP 7 2015
WEDNESDAY...UPPER WAVE IN NORTHWEST FLOW ALOFT WILL PROVIDE SHOWER
CHANCES...ALTHOUGH MOST 00Z GUIDANCE IS SLOWER AND TIMES THIS
FORCING INTO THE REGION MORE WEDNESDAY NIGHT. THIS WOULD ALLOW
SLIGHTLY WARMER TEMPERATURES DURING THE DAY ON WED. TRENDED THE
FORECAST ACCORDINGLY FOR POPS AND TEMPS.
THURSDAY-SUNDAY...LOW AMPLITUDE LONG WAVE RIDGE/TROUGH OVER
WESTERN CANADA/CENTRAL NORTH AMERICA RESPECTIVELY AMPLIFIES A BIT
BY THE END OF THE PERIOD. THE GFS WAS A FASTER AND A LOWER
AMPLITUDE SOLUTION THAN THE ECMWF. BOTH THE ECMWF AND THE GFS HAVE
BEEN TRENDING SLOWER OVER THE LAST COUPLE MODEL RUNS. TEND TO
PREFER THE ECMWF.
HIGH TEMPS WERE INCREASED ONE TO THREE DEGREES FOR THU AND INCREASED
ONE OR TWO DEGREES FOR FRI AND SAT. HIGH TEMPS WERE DECREASED TWO TO
THREE DEGREES FOR SUN FROM YESTERDAYS FORECAST PACKAGE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 644 AM CDT MON SEP 7 2015
VFR THROUGH THE PERIOD. CLEAR SKY THIS MORNING WILL GIVE WAY TO
INCREASING MID-LEVEL CLOUDS...THEN LIKELY CLEAR AGAIN BY TUESDAY
MORNING.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...TG
LONG TERM...TG/HOPPES
AVIATION...TG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
846 AM CDT MON SEP 7 2015
.UPDATE...
ISSUED AT 843 AM CDT MON SEP 7 2015
QUICK UPDATE TO BLEND RADAR TRENDS TO THE TIME LAGGED ENSEMBLE OF
THE 10-12 UTC HRRR ITERATIONS...AND ADD AN ISOLATED MENTION OF
THUNDERSTORMS SOUTH CENTRAL THIS MORNING AND THROUGH THE AFTERNOON
WITH A FEW LIGHTNING STRIKES OBSERVED THUS FAR.
UPDATE ISSUED AT 623 AM CDT MON SEP 7 2015
ONLY CHANGE FOR MORNING UPDATE WAS TO TRIM POPS BACK A BIT IN THE
EARLY MORNING AS EXPECT THE ONSET OF SHOWERS WILL BE DELAYED A
LITTLE. OTHERWISE...GOING FORECAST WAS IN GOOD SHAPE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 310 AM CDT MON SEP 7 2015
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL CHANCES FOR
SHOWERS TODAY SOUTHWEST AND CENTRAL...AND COOL/BELOW NORMAL
TEMPERATURES BOTH TODAY AND TUESDAY.
CURRENTLY...UPPER LEVEL LOW PRESSURE SPINNING OVER SOUTHERN
SASKATCHEWAN WITH A 100KT UPPER LEVEL JET ROUNDING THE BASE OF
THE LOW INTO THE WESTERN DAKOTAS. STRONG FLOW ALOFT RESULTING IN
MID LEVEL MOISTURE ADVECTION WITH INCREASING MID AND HIGH LEVEL
CLOUDINESS. DESPITE CLOUDS SOUTHWEST VERY DRY DEWPOINTS IN THE
30S RESULTING IN TEMPERATURES IN THE LOW 40S AND EVEN A FEW UPPER
30S.
THE UPPER JET STREAK IS INDUCING A SUBTLE SURFACE TROUGH OVER
WESTERN SOUTH DAKOTA EARLY THIS MORNING...AND WILL EVENTUALLY
DEVELOP INTO SOUTHWEST AND SOUTH CENTRAL NORTH DAKOTA LATER THIS
MORNING AND AFTERNOON. COUPLED WITH FORCING ALOFT EXPECT SHOWERS
TO DEVELOP NEAR THE TROUGH AXIS AS IT SLOWLY MOVES EAST TODAY.
WHILE WE WILL REALIZE SOME MOISTURE RETURNING BACK INTO THE AREA
INSTABILITY IS VERY MINIMAL SO REMOVED ALL MENTION OF THUNDER FROM
THE FORECAST. FORCING ALOFT MOVES OFF TO OUR EAST AFTER 00Z SO
MAINTAINED A DRY EVENING AND OVERNIGHT PERIOD.
UPPER LOW CONTINUES EAST ACROSS SOUTH CENTRAL CANADA...ROTATING
ANOTHER EMBEDDED WAVE AND ASSOCIATED JET STREAK ACROSS THE STATE
LATE MONDAY NIGHT INTO TUESDAY. AT THIS TIME SFC FORCING LOOKS NIL
WITH SFC HIGH PRESSURE MOVING EAST ACROSS THE REGION SO KEPT THE
TUESDAY MORNING AND AFTERNOON PERIOD DRY FOR NOW.
HIGH TEMPERATURES BOTH TODAY AND TUESDAY VERY COMFORTABLE IN THE
UPPER 60S TO MID 70S. TEMPERATURES TONIGHT SHOULD BE SIMILAR TO
CURRENT CONDITIONS...40S WITH A FEW AREAS DROPPING INTO THE UPPER
30S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 248 AM CDT MON SEP 7 2015
BROAD SHORT WAVE ROTATING AROUND HUDSON BAY LOW PASSES OVER THE
AREA WEDNESDAY AND WEDNESDAY NIGHT...POSSIBLY BRINGING SOME
PRECIPITATION TO OUR AREA. FOR THE REST OF THE WORK
WEEK...NORTHWESTERLY FLOW WITH RIDGING OVER THE WESTERN CONUS WILL
BRING QUIET WEATHER AND COMFORTABLE TEMPERATURES TO THE AREA.
WARMER CONDITIONS RETURN FOR SATURDAY AS RIDGE AXIS PASSES OVER.
BEHIND THE RIDGE...A FEW THUNDERSTORMS MAY DEVELOP INTO SATURDAY
NIGHT. AVERAGE TEMPERATURES RETURN FOR SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 843 AM CDT MON SEP 7 2015
VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD. INCREASING
MID AND HIGH LEVEL CLOUDS THROUGH MONDAY MORNING. LIGHT SHOWERS
POSSIBLE MONDAY MORNING/AFTERNOON FOR KBIS-KJMS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...NH
LONG TERM...JJS
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
644 AM CDT MON SEP 7 2015
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 348 AM CDT MON SEP 7 2015
THE MAIN CHALLENGE THIS PERIOD WILL BE SHOWER CHANCES AND
TEMPERATURES. THE AIRMASS CHANGE HAS OCCURRED WITH MUCH COOLER
AND DRIER ADVECTING INTO THE REGION. UPPER LOW WILL SLOWLY
PROPAGATE EAST ACROSS CANADA...AND MOST MODEL GUIDANCE SUGGESTS A
WAVE WITHIN THIS FLOW PATTERN WILL LEAD TO SHOWERS THIS AFTERNOON.
GIVEN THE DRY AIRMASS IN PLACE ANY RADAR RETURNS WILL LIKELY
APPEAR WORSE THAN WHAT IS OCCURRING AT THE GROUND...BUT DID
INCLUDE ISOLD SHOWERS AS HRRR INDICATES WEAK BANDING POTENTIAL.
ANTICIPATE SOLAR TODAY...WHICH SHOULD ALLOW MAX TEMPS INTO THE
70S.
DRY ON TUESDAY...AND SLIGHTLY COOLER AS THE UPPER LOW IN CANADA
SHIFTS EAST.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 348 AM CDT MON SEP 7 2015
WEDNESDAY...UPPER WAVE IN NORTHWEST FLOW ALOFT WILL PROVIDE SHOWER
CHANCES...ALTHOUGH MOST 00Z GUIDANCE IS SLOWER AND TIMES THIS
FORCING INTO THE REGION MORE WEDNESDAY NIGHT. THIS WOULD ALLOW
SLIGHTLY WARMER TEMPERATURES DURING THE DAY ON WED. TRENDED THE
FORECAST ACCORDINGLY FOR POPS AND TEMPS.
THURSDAY-SUNDAY...LOW AMPLITUDE LONG WAVE RIDGE/TROUGH OVER
WESTERN CANADA/CENTRAL NORTH AMERICA RESPECTIVELY AMPLIFIES A BIT
BY THE END OF THE PERIOD. THE GFS WAS A FASTER AND A LOWER
AMPLITUDE SOLUTION THAN THE ECMWF. BOTH THE ECMWF AND THE GFS HAVE
BEEN TRENDING SLOWER OVER THE LAST COUPLE MODEL RUNS. TEND TO
PREFER THE ECMWF.
HIGH TEMPS WERE INCREASED ONE TO THREE DEGREES FOR THU AND INCREASED
ONE OR TWO DEGREES FOR FRI AND SAT. HIGH TEMPS WERE DECREASED TWO TO
THREE DEGREES FOR SUN FROM YESTERDAYS FORECAST PACKAGE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 644 AM CDT MON SEP 7 2015
VFR THROUGH THE PERIOD. CLEAR SKY THIS MORNING WILL GIVE WAY TO
INCREASING MID-LEVEL CLOUDS...THEN LIKELY CLEAR AGAIN BY TUESDAY
MORNING.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...TG
LONG TERM...TG/HOPPES
AVIATION...TG
AREA FORECAST DISCUSSION
NWS NORMAN OK
614 AM CDT MON SEP 7 2015
.DISCUSSION...
AVIATION DISCUSSION FOR THE 12Z TAFS IS BELOW.
&&
.AVIATION...
VFR CONDITIONS ARE EXPECTED TO CONTINUE.
MBS
&&
.PREV DISCUSSION... /ISSUED 347 AM CDT MON SEP 7 2015/
DISCUSSION...
HOT WEATHER TODAY AND TUESDAY IS THE FIRST CONCERN...THEN RAIN
CHANCES MAINLY TUESDAY...WEDNESDAY...AND THURSDAY NIGHT AS WELL
AS COOLER WEATHER ARE THE NEXT CONCERNS.
THIS MORNING...LATEST HRRR RUNS HAVE BEEN HINTING THAT A FEW
HIGH BASED SHOWERS AND THUNDERSTORMS MAY FORM OVER NORTHERN
OKLAHOMA...NORTH OF A ELK CITY TO STILLWATER LINE. FOR NOW...DID
NOT MENTION AS NOT SURE THIS WILL OCCUR DUE TO DECENT CAPPING.
THIS AFTERNOON AND EARLY EVENING...A FEW THUNDERSTORMS MAY FORM
SIMILAR TO YESTERDAY IN PARTS OF SOUTHERN OKLAHOMA...MAINLY SOUTH
OF A ARDMORE TO COALGATE LINE AS WELL AS PERHAPS FAR NORTHWESTERN
OKLAHOMA CLOSER TO A FRONT. KEPT 20 PERCENT CHANCES IN THESE
LOCATIONS. ANY STORM WILL MOVE FAIRLY SLOWLY AND BE CAPABLE OF
PRODUCING GUSTY WINDS UP TO 50 MPH AND WELL AS LOCALIZED
DOWNPOURS.
THE HEAT TODAY WILL BE THE MAIN STORY. THINK HIGHS WILL BE VERY
SIMILAR TO YESTERDAY. GENERALLY WENT TOWARDS THE HOTTER SIDE OF
MODEL GUIDANCE. WILL HOLD OFF ON ISSUING A HEAT ADVISORY THOUGH
HEAT INDICES WILL FLIRT WITH THE 105 DEGREE MARK IN MANY
LOCATIONS.
LATE TONIGHT INTO TUESDAY MORNING...A FEW STORMS MAY FORM NEAR
THE APPROACHING COLD FRONT IN NORTHERN OKLAHOMA. KEPT 20 PERCENT
CHANCES TO ACCOUNT FOR THIS. OTHERWISE...RAINFREE AND MUGGY
CONDITIONS WILL PERSIST.
TUESDAY AFTERNOON AND NIGHT...RAIN CHANCES WILL INCREASE ACROSS
THE ENTIRE AREA WITH THE PASSAGE OF A COLD FRONT. STORMS MAY BE
NEAR THE FRONT AND PERHAPS ORGANIZE INTO A LINE. A FEW STORMS MAY
BE STRONG TO PERHAPS SEVERE WITH DAMAGING WINDS UP TO 70 MPH AS
THE MAIN HAZARDS AS DCAPE VALUES WILL EXCEED 1000 J/KG IN A HOT
DEEPLY MIXED ENVIRONMENT. NOT SURE IF STORMS WILL BECOME TOO
WIDESPREAD AND VERY ORGANIZED AS 0-6 KM SHEAR MAY BE MARGINAL.
LOCALLY HEAVY RAINFALL COULD OCCUR AS WELL. HIGHEST RAIN CHANCES
APPEAR TO BE NEAR AND EAST OF I-35.
HIGHS ON TUESDAY MAY SOAR JUST AHEAD OF THE COLD FRONT...THUS WENT
ABOVE MODEL GUIDANCE IN MOST LOCATIONS EXCEPT FAR NORTHERN
OKLAHOMA WHERE MORE CLOUDS AND RAIN MAY KEEP THEM DOWN A BIT.
WEDNESDAY...SOME SHOWERS AND STORMS MAY LINGER OVER SOUTHERN
OKLAHOMA AND WESTERN NORTH TEXAS...MAINLY DURING THE MORNING
HOURS. COOLER TEMPERATURES WILL LIKELY RESULT...THOUGH IT MAY
REMAIN FAIRLY MUGGY.
WEDNESDAY NIGHT THROUGH SUNDAY...COOLER WEATHER IS STILL
FORECAST...THOUGH THERE IS SOME UNCERTAINTY DURING THIS TIME FRAME
WITH THE TIMING OF SYSTEMS AND HOW COOL IT WILL BE. LATEST MODELS
WERE NOT QUITE AS COOL DURING THIS TIME FRAME. THERE SEEMED TO BE
SIGNAL FOR STORMS THURSDAY NIGHT ACROSS MUCH OF THE AREA. RAIN
CHANCES WERE KEPT THURSDAY NIGHT THROUGH SATURDAY NIGHT ACROSS
PARTS OF THE AREA...THOUGH TIMING AND LOCATIONS REMAIN UNCERTAIN.
MBS
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 99 74 96 69 / 10 10 30 60
HOBART OK 103 75 101 69 / 0 10 30 50
WICHITA FALLS TX 100 73 100 72 / 10 0 10 60
GAGE OK 101 76 94 64 / 10 10 40 30
PONCA CITY OK 99 77 91 67 / 10 10 50 70
DURANT OK 97 74 97 72 / 20 20 20 70
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
17
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1003 AM CDT MON SEP 7 2015
.UPDATE...
ANOTHER HOT AND HUMID DAY IS UPCOMING FOR THE MIDSOUTH.
TEMPERATURES ARE ALREADY IN THE LOW TO MID 80S AS OF 10AM. ONCE
AGAIN THE HRRR IS OVERDOING AFTERNOON THUNDERSTORM COVERAGE.
EXPECT COVERAGE TO BE MINIMAL AT BEST. HIGHS TODAY WILL REACH THE
MID 90S WITH HEAT INDICES NEAR 100. NO CHANGES TO THE PREVIOUS
FORECAST WERE NECESSARY.
&&
.PREV DISCUSSION... /ISSUED 608 AM CDT MON SEP 7 2015/
UPDATE...
UPDATED TO ADD 12Z AVIATION DISCUSSION.
PREV DISCUSSION... /ISSUED 317 AM CDT MON SEP 7 2015/
DISCUSSION...
THE MID SOUTH WILL REMAIN POSITIONED BETWEEN UPPER LEVEL HIGH
PRESSURE OVER THE SOUTHERN PLAINS AND AN UPPER LEVEL LOW PRESSURE
SYSTEM OVER GEORGIA TODAY. THIS WILL ALLOW FOR THE CONTINUATION OF
DRY...HOT...AND HUMID CONDITIONS. THE UPPER LOW WILL MOVE
SOUTHWESTWARD THROUGH TUESDAY AND SHOULD SPREAD ISOLATED SHOWERS
AND THUNDERSTORMS INTO PORTIONS OF WEST TENNESSEE NEAR THE
TENNESSEE RIVER AND NORTHEAST MISSISSIPPI BY TUESDAY AFTERNOON.
ELSEWHERE...DRY AND HOT WEATHER WILL CONTINUE ALONG WITH HUMID
CONDITIONS.
THE UPPER LEVEL RIDGE EXTENDING OVER THE AREA EARLY IN THE WEEK
WILL BREAK DOWN BY WEDNESDAY AS A SHORTWAVE TROUGH DIGS ACROSS THE
CENTRAL PLAINS INTO THE LOWER MISSISSIPPI VALLEY. THIS SHOULD
INCREASE CHANCES FOR SHOWERS AND THUNDERSTORMS ACROSS THE AREA AND
KNOCK TEMPERATURES BACK DOWN TO NEAR NORMAL LEVELS FOR THIS TIME
OF YEAR. THE UPPER LEVEL TROUGH SHOULD REMAIN OVER THE REGION
INTO THURSDAY WITH CONTINUED CHANCES FOR SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS.
A STRONGER SHORTWAVE WILL DIVE SOUTHEAST INTO THE REGION ON FRIDAY
AND HELP TO PUSH A COLD FRONT SOUTH ACROSS THE FORECAST AREA.
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL AGAIN BE
POSSIBLE ON FRIDAY AS THE FRONT MOVES THROUGH. SURFACE HIGH
PRESSURE SHOULD BUILD INTO THE AREA AS UPPER LEVEL TROUGHING
REMAINS OVER THE EASTERN HALF OF THE NATION. DRY WEATHER ALONG
WITH COOLER AND LESS HUMID CONDITIONS CAN BE EXPECTED FOR NEXT
WEEKEND.
BY EARLY NEXT WEEK...ATTENTION WILL TURN TO THE WESTERN GULF OF
MEXICO WHERE MODELS ARE HINTING AT POTENTIAL TROPICAL
DEVELOPMENT. LATEST GUIDANCE BRINGS ANY DEVELOPING SYSTEM NORTH
THROUGH THE ARKLATEX AND INTO OUR REGION EARLY NEXT WEEK. PLAN TO
CARRY AN INCREASE IN RAIN CHANCES EARLY NEXT WEEK...BUT WILL NOT
GO AS HIGH AS CURRENT GUIDANCE UNTIL THIS SOLUTION LOOKS MORE
LIKELY. THIS SCENARIO WILL BE WATCHED CLOSELY OVER THE NEXT
SEVERAL DAYS.
JLH
.AVIATION...
12Z TAF CYCLE
PATCHY FOG MAY PRODUCE TEMPORARY MVFR/IFR VISIBILITIES AT MKL/JBR
THROUGH 07/13Z AND AGAIN LATE TONIGHT AT MKL/JBR/TUP.
OTHERWISE...VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THE PERIOD.
LIGHT WINDS WILL BECOME SE WINDS BETWEEN 5-8 KTS AFTER 07/15Z.
CJC
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
632 AM CDT MON SEP 7 2015
.UPDATE...
FOR 12Z AVIATION.
&&
.DISCUSSION...
LATEST SURFACE OBSERVATIONS SHOWS TEMPERATURES IN THE 60S TO LOW
70S ACROSS THE MID STATE WITH DEWPOINTS ALSO IN THE 60S UNDER
NEARLY CLEAR SKIES. SEVERAL OBS ALSO SHOWING PATCHY FOG ALTHOUGH
NO DENSE FOG HAS BEEN NOTED THUS FAR. WILL KEEP MENTION OF PATCHY
FOG IN THE GRIDS/ZONES THROUGH 14Z. OTHERWISE...ANOTHER HOT AND
HUMID DAY IS ON TAP WITH TEMPERATURES RISING INTO THE 80S PLATEAU
AND LOW 90S ELSEWHERE...SIMILAR TO YESTERDAY. WATER VAPOR IMAGERY
DEPICTS AN UPPER LEVEL LOW CENTERED OVER GEORGIA...WITH DRY AIR ON
THE WEST SIDE OF THE LOW CURRENTLY ACROSS THE MID STATE. 00Z
GFS/ECMWF SLOWLY RETROGRADE THIS LOW TO THE SOUTHWEST OVER THE
NEXT FEW DAYS WHILE MOISTURE ADVECTS WESTWARD AROUND THE NORTH
SIDE OF THE LOW INTO MIDDLE TENNESSEE. THUS EXPECTING ISOLATED
SHOWERS AND STORMS AGAIN TODAY...BUT MAINLY TO THE EAST OF I-65 AS
THE DRY AIR ALOFT LIMITS COVERAGE OVER WESTERN ZONES. THIS
THINKING IS IN LINE WITH THE LATEST HRRR MODEL RUNS WHICH KEEPS
CONVECTION MAINLY OVER THE EASTERN HALF OF THE CWA.
POPS WILL INCREASE WESTWARD ON TUESDAY AS PWATS RISE BACK ABOVE
1.5 INCHES ACROSS MUCH OF THE FORECAST AREA. BY WEDNESDAY...THE
MAIN BELT OF WESTERLIES ACROSS THE NORTHERN CONUS BEGINS TO SINK
SOUTHWARD ACROSS THE TENNESSEE VALLEY...WITH A COLD FRONT PROGGED
TO MOVE ACROSS THE FORECAST AREA ON THURSDAY. THE INCREASE IN
UPPER LEVEL SUPPORT ALONG WITH PWATS RISING TO AROUND 1.75 INCHES
AND THE FRONTAL FOCUS ALL INDICATE FAIRLY WIDESPREAD SHOWERS AND
STORMS WEDNESDAY INTO THURSDAY...WARRANTING CHANCE TO LIKELY POPS
ALONG WITH MUCH COOLER HIGH TEMPS DUE TO PRECIP/CLOUD COVER. 00Z
GFS/ECMWF INDICATE AREA WILL DRY OUT ON FRIDAY...BUT A FEW SHOWERS
ARE POSSIBLE FRIDAY NIGHT AND SATURDAY AS A SECONDARY SURGE OF
COOLER AIR MOVES ACROSS. VERY PLEASANT FALL-LIKE CONDITIONS ARE
ANTICIPATED SATURDAY AND SUNDAY WITH LOW HUMIDITY AND
TEMPERATURES SEVERAL DEGREES BELOW NORMAL FOR THIS TIME OF YEAR.
&&
.AVIATION...
12Z TAF DISCUSSION.
MVFR TO LIFR FOG HAS OCCURRED AT KCKV AND KCSV THIS MORNING...AND
COULD CONTINUE UNTIL AROUND 14Z OR SO. OTHERWISE EXPECT VFR
CONDITIONS TO CONTINUE THROUGH THE DAY. FOG MAY AGAIN RETURN
TONIGHT AND INTO THE EARLY MORNING TOMORROW. WINDS WILL BE LIGHT
AND MAINLY OUT OF THE SOUTHEAST TODAY.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
06
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
628 AM CDT MON SEP 7 2015
.AVIATION...
/12Z TAFS/
MVFR stratus in the Hill Country was advecting north to the I-10
corridor from Sonora to Junction at 11Z. Will include a tempo for
MVFR ceiling at KSOA and KJCT through 16Z. Otherwise, south to
southeast winds of 10 KTS or less, and VFR conditions are expected
across the rest of the terminals.
&&
.PREV DISCUSSION... /ISSUED 356 AM CDT MON SEP 7 2015/
SHORT TERM...
(Today and Tonight)
It will be another persistence forecast today, with the upper
ridge parked over West Central Texas. The HRRR model again
develops isolated afternoon convection, as it has done the last
several days, and will discount the potential. Temperatures should
again rise into the upper 90s with a few areas reaching 100.
04
LONG TERM...
(Tuesday through Sunday)
We looking for one more hot and dry day across west central TX
before the synoptic pattern shifts to one more conducive for
increasing rain chances and more seasonal temperatures. The
subtropical ridge will be building slowly westward on Tuesday as a
strong trough moves across the northern Plains. This trough is
progged to dig over the eastern CONUS, allowing the ridge to build
over the western states. This will result in northwest flow aloft
for our neck of the woods. A weak cold front will move south into
the Lone Star State Tuesday afternoon, likely reaching the south
Plains during the evening hours. Compressional heating ahead of
this cold front will promote afternoon highs in the mid 90s to
near 100 degrees.
Convection is expected to initiate along this cold front as it
approaches Tuesday evening. Some of this activity is expected to
move southeast into the Big Country, maybe as far south as the
Colorado River, Tuesday night into early Wednesday morning. The
cold front is expected to weaken by this time, but convective
outflow should serve as the effective frontal boundary, moving
south into the Concho Valley, and eventually the I-10 corridor,
by Wednesday afternoon. Scattered showers and thunderstorms are
expected to develop, especially along and behind the front. While
rainfall is not expected to be particularly heavy, it should be
fairly widespread with good coverage across the CWA. The increased
cloud cover and precipitation will keep temperatures in check.
Forecast highs for Wednesday afternoon are in the upper 80s to
lower 90s; however, they could be lowered further if rain is
indeed as widespread as anticipated.
The effective cold front will move south over the Edwards Plateau
Wednesday night into Thursday. This will shift the highest rain
chances south of a San Angelo-Brownwood line, favoring the I-10
corridor. In fact, PoPs were removed for areas north of I-20 on
Thursday. This boundary will become more diffuse by the end of the
work-week, but slight chance PoPs were retained over the southern
1/3 of the CWA for Friday. Total rainfall amounts will likely
average less than 1/2 inch, some some areas will see locally
higher amounts, especially over the southeast quadrant of the CWA.
Temperatures are forecast to remain near seasonal norms Thursday
and Friday, generally in the upper 80s to lower 90s. Overnight
lows during this time will be in the mid 60s to near 70 degrees.
PoPs were removed over the weekend as the main upper-level trough
is expected to be to our east by Saturday. Temperatures are
expected to remain near climatology. There remain some differences
in the synoptic pattern, the most notable of which is the tropical
system generated early next week in the western Gulf by the ECMWF.
At the same time, the GFS creates no such system and maintains a
weak cut-off upper-low over the Red River. Will continue to
monitor the model trends at this time, keeping a dry forecast over
the weekend.
Johnson
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 99 76 98 73 / 0 0 5 30
San Angelo 100 75 100 74 / 0 0 0 10
Junction 98 74 97 75 / 0 0 5 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
99/99/04
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
955 AM MDT MON SEP 7 2015
.UPDATE...
ISSUED AT 950 AM MDT MON SEP 7 2015
LATEST GUIDANCE SHOWING SOME PRETTY HIGH CAPE OUT OVER THE
SOUTHERN NEBRASKA PANHANDLE ALONG AND SOUTH OF AN ALLIANCE TO
CHEYENNE LINE THIS AFTERNOON. SPC HRRR SIMULATED RADAR SHOWING
QUITE A BIT OF CONVECTION OUT IN THIS AREA THIS AFTERNOON AND
EARLY EVENING. WENT AHEAD AND UPPED POPS FOR THIS AREA THIS
AFTERNOON/EARLY EVENING. UPDATES HAVE BEEN SENT.
AS FOR THE CURRENT RFW...LOOKS TO BE IN PRETTY GOOD SHAPE. POOR
OVERNIGHT RH RECOVERIES FOR 301 AND 302...SO WE ARE STARTING OFF
PRETTY LOW ALREADY THIS MORNING. NAM SOUNDINGS SHOWING 35-40KTS OF
WIND POSSIBLY MIXING DOWN TO THE SURFACE THIS AFTERNOON. WILL KEEP
CURENT HEADLINES AS THEY ARE.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 415 AM MDT MON SEP 7 2015
PREDAWN WATER VAPOR IMAGERY SHOWED A UPPER LOW SITUATED OVER
CENTRAL SASKATCHEWAN WITH A TROUGH AXIS THROUGH THE NORTHERN
ROCKIES AND GREAT BASIN. UPPER RIDGE EXTENDED FROM NORTHERN MX
TO THE MIDWEST. THE REGIONAL SURFACE ANALYSIS PLACED A COLD
FRONT FROM LAKE SUPERIOR THROUGH CENTRAL IA AND KS THEN NORTH
ALONG THE CO FRONT RANGE AND WEST THROUGH CENTRAL UT. A WEAK
TROUGH WAS LOCATED NEAR THE LARAMIE RANGE. WIDELY SCATTERED
CONVECTION DEVELOPED IN THE VICINITY OF THESE BOUNDARIES...
AIDED BY LIFT FROM RIGHT REAR QUADRANT OF UPPER LEVEL JET.
REGIONAL RADARS DETECTED SHOWERS AND ISOLATED TSTORMS MOVING
NORTHEAST ACROSS WESTERN NE AS WELL AS FROM NORTHWEST CO INTO
SOUTH CENTRAL WY.
THERE IS GOOD AGREEMENT WITH THE 00Z SHORT RANGE MODEL GUIDANCE
PROGGING THE UPPER TROUGH AXIS TO THE WEST TO TRANSLATE EAST
DURING THE NEXT 24 HOURS. THE RIGHT REAR QUADRANT OF THE UPPER
JET WILL REMAIN OVER THE CWA THROUGH TONIGHT. THIS FEATURE ALONG
WITH A COOL FRONT DROPPING SOUTHEAST THROUGH THE PLAINS LATE
TODAY WILL TRIGGER WIDELY SCATTERED AFTERNOON AND EVENING
CONVECTION...MAINLY FROM SOUTHERN LARAMIE RANGE NORTHEAST INTO THE
NE PANHANDLE. TEMPERATURES TODAY WILL BE SIMILAR TO YESTERDAY WITH
HIGHS IN THE 60S AND 70S WEST TO THE 80S EAST. THERE WILL BE A
30-DEGREE WEST TO EAST DEW POINT GRADIENT THIS AFTERNOON. GUSTY
WESTERLY WINDS AND LOW HUMIDITIES WILL INCREASE THE FIRE DANGER
OVER PORTIONS OF EAST AND SOUTH CENTRAL WY THIS AFTERNOON.
TUESDAY WILL BE 5 TO 10 DEGREES COOLER ACROSS THE PLAINS FOLLOWING
THE FRONTAL PASSAGE. THE DRIER AIR MASS WILL SPREAD EAST INTO THE
NE PANHANDLE DURING THE DAY. BREEZY WEST WINDS AND LOW HUMIDITIES
WILL CREATE NEAR-CRITICAL FIRE WEATHER CONDITIONS WEST OF THE
LARAMIE RANGE. THE FLOW ALOFT BECOMES MORE ZONAL WEDNESDAY. IT
WILL BE DRY AND BREEZY DURING THE AFTERNOON ALONG AND WEST OF THE
LARAMIE RANGE. TEMPERATURES WEDNESDAY WILL WARM ABOUT 5 DEGREES.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 330 AM MDT MON SEP 7 2015
WEDNESDAY NIGHT/THURSDAY...FLOW ALOFT REMAINS NORTHWEST. WITH
LIMITED LOW AND MID LEVEL MOISTURE...NOT EXPECTING ANY PRECIPITATION.
FRIDAY...NEAR THE SAME OR SLIGHTLY WARMER THAN THURSDAY BASED ON
THICKNESS AND HEIGHT CHANGES. LOW AND MID LEVEL MOISTURE LOOKS TOO
SCANT FOR ANY PRECIPITATION.
SATURDAY...SLOW WARMING TREND CONTINUES AS RIDGING ALOFT BECOMES
MORE PRONOUNCED OVERHEAD. STILL NOT ENOUGH LOW AND MID LEVEL
MOISTURE FOR SHOWER AND THUNDERSTORM FORMATION.
SUNDAY...FLOW ALOFT BECOMES ZONAL...INDUCING EVEN WARMER TEMPERATURES.
STILL DRY WITH LIMITED CLOUD COVER.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 325 AM MDT MON SEP 7 2015
VFR. ISOLATED SHOWERS AND THUNDERSTORMS DEVELOP THIS AFTERNOON AND
EVENING SOUTH OF A LARAMIE TO ALLIANCE LINE. THE STRONGER STORMS
WILL PRODUCE GUSTY AND ERRATIC WIND GUSTS AS WELL AS OCCASIONAL
LIGHTNING.
&&
.FIRE WEATHER...
ISSUED AT 310 AM MDT MON SEP 7 2015
CRITICAL FIRE WEATHER CONDITIONS WILL DEVELOP ONCE AGAIN THIS
AFTERNOON FOR PORTIONS OF EAST AND SOUTH CENTRAL WYOMING. WESTERLY
WINDS WILL FREQUENTLY GUST FROM 25 TO 35 MPH WITH MINIMUM RELATIVE
HUMIDITIES DECREASING TO 10 TO 15 PERCENT. THESE CRITICAL CONDITIONS
WILL DEVELOP ACROSS MOST OF ZONE 302...WESTERN PORTIONS OF ZONE
301...AND NORTHERN PORTIONS OF ZONES 303 AND 308. A COOL FRONT
WILL MOVE ACROSS THE PLAINS THIS EVENING...WITH SLIGHTLY COOLER
TEMPERATURES FOR TUESDAY. THERE IS A SLIGHT CHANCE OF AFTERNOON
AND EVENING SHOWERS AND THUNDERSTORMS ALONG AND EAST OF THE
SOUTHERN LARAMIE RANGE. NEAR CRITICAL FIRE WEATHER CONDITIONS ARE
EXPECTED TUESDAY AND WEDNESDAY FOR AREAS ALONG AND WEST OF THE
LARAMIE RANGE.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR WYZ301>303-308.
NE...NONE.
&&
$$
UPDATE...GCC
SHORT TERM...MAJ
LONG TERM...RUBIN
AVIATION...RUBIN
FIRE WEATHER...MAJ
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
225 PM MST MON SEP 7 2015
.SYNOPSIS...
ISOLATED SHOWERS AND THUNDERSTORM EXPECTED TODAY WITH TEMPERATURES
NEAR NORMAL. MOISTURE LEVELS ARE EXPECTED TO INCREASE TUESDAY THROUGH
THURSDAY...ESPECIALLY FOR SOUTHEASTERN CALIFORNIA AND THE YUMA
VICINITY. BY THE END OF THE WEEK TEMPERATURES WILL BE INCREASING WITH
MUCH LOWER CHANCES FOR ANY STORMS.
&&
.DISCUSSION...
MOISTURE LEVELS ARE ON THE INCREASE ACROSS THE REGION AS OUTFLOW FROM
HURRICANE LINDA OFF THE BAJA CALIFORNIA COAST IS STARTING TO SURGE
INTO THE DESERT SOUTHWEST. WATER VAPOR SATELLITE IMAGERY CLEARY SHOWS
THE WESTERN EDGE OF THE MOISTURE SURGE AS STRETCHING FROM SOUTHEAST
CA UP TO NORTHERN COCONINO COUNTY IN ARIZONA WITH THE MOISTURE PLUME
SURGING ALL THE WAY TO THE NORTHEAST INTO UTAH AND COLORADO. SHOWER
ACTIVITY IS BUILDING UP ACROSS ARIZONA WITH THE GREATEST ACTIVITY IN
YAVAPAI AND COCONINO COUNTIES AT THIS TIME. THE EXTENSIVE CLOUD COVER
ACROSS THE GREATER PHOENIX AREA IS HELPING DAMPEN THE TEMPERATURE
SOMEWHAT WITH A HIGH SO FAR OF 97 IN PHOENIX TWO HOURS AGO. WEBCAMS
AND RADAR INDICATE SOME LIGHT SHOWERS ACROSS THE VALLEY EARLY THIS
AFTERNOON. SOME CLEARING IS EVIDENT IN SOUTHWEST MARICOPA COUNTY ON
THE VISIBLE SATELLITE IMAGERY AS OF 2 PM AND THIS CLEARING SHOULD
REACH THE PHOENIX AREA BY LATE AFTN.
MODELS INDICATE THE MOISTURE SURGE WILL CONTINUE THROUGH LATE
WEDNESDAY. THE HRRR IN PARTICULAR IN THE SHORT TERM IS DEVELOPING A
LINE OF MODERATE RAIN AND THUNDERSTORMS ACROSS NORTHERN
YUMA...SOUTHEAST LA PAZ...AND NORTHWEST MARICOPA COUNTY LATER THIS
EVENING AS WELL AS MORE ACTIVITY FOR SOUTHERN MARICOPA AND PINAL
COUNTIES. HIGH PRESSURE WILL BEGIN TO MOVE BACK OVER THE SOUTHWEST BY
FRIDAY SETTLING OVER SOUTHERN NEVADA ...LARGELY CUTTING OFF THE
TROPICAL MOISTURE FLOW AND DROPPING CHANCES FOR RAIN AND INCREASING
TEMPERATURES FOR THE WEEKEND.
&&
.PREVIOUS DISCUSSION...
TODAY AND TUESDAY...
SATELLITE AND RADAR DATA EARLY THIS MORNING SHOW DEBRIS CLOUDS WITH
SOME EMBEDDED SHOWERS AND EVEN A STRAY THUNDERSTORM DEVELOPING OVER
SOUTH-CENTRAL ARIZONA. THE LATEST MODELS HAVE ALL BEEN INDICATING
THIS TO VARYING DEGREES. THUS HAVE SLIGHT CHANCE POPS GOING ALL DAY
OVER THE LOWER DESERTS OF SOUTH-CENTRAL ARIZONA...THOUGH THICKER
CLOUDS WILL LIKELY NOT HANG AROUND ALL DAY. NUDGED FORECAST TEMPS
DOWN SLIGHTLY FROM PREVIOUS PACKAGE TO ACCOUNT FOR MORE CLOUD COVER
DESPITE THE WESTWARD EXPANSION OF HIGH PRESSURE. SATURATED LAYERS
LOOK TO BE EVEN THICKER EAST OF METRO PHOENIX FOR HIGHER POPS
THERE...DESPITE LITTLE MODEL CAPE. IN FACT BEST MODEL CAPE FOR OUR
FORECAST AREA CONTINUES TO BE OVER SOUTHWEST ARIZONA BUT NOT REALLY
LOOKING AT MUCH DIFFERENCE FROM YESTERDAY. THUS POPS REMAIN MODEST
TODAY. OVERALL MODELS NOT INDICATING MUCH IMPROVEMENT IN MOISTURE
AND CAPE FOR TUESDAY. THOUGH THERE SHOULD BE LESS CLOUDINESS...IT
WILL TEND TO BE OFFSET BY THE EXPANDING RIDGE AND ASSOCIATED
ANTICYCLONIC FLOW.
WEDNESDAY AND THURSDAY...
LATEST MODELS ARE INDICATING THAT MOISTURE FROM HURRICANE LINDA WILL
MOVE INTO THE AREA WEDNESDAY. LINDA WILL REMAIN OFF THE BAJA COAST
BUT WILL BE CLOSE ENOUGH SUCH THAT THERE LOOKS TO BE BOTH A GULF
SURGE AND MID AND HIGH CLOUDS MOVING IN. GFS IS MORE AGGRESSIVE WITH
THE CLOUDINESS THAN NAM WITH ECMWF IN BETWEEN. THERE MAY BE TOO MUCH
CLOUDINESS TO DESTABILIZE ENOUGH FOR FULL FLEDGED THUNDERSTORMS OR
EVEN CONVECTIVE SHOWERS...ESPECIALLY IF GFS IS CORRECT. THIS IS
REFLECTED IN THE MODEL CIN WHICH REMAINS FAIRLY HIGH. THUS DESPITE
THE MOISTURE...POPS REMAIN QUITE MODEST. A CAVEAT IS THAT THERE MAY
BE A PERTURBATION IN THE FLOW...AS DEPICTED BY GFS...WHICH CLOUD
POSSIBLY AID IN SHOWER DEVELOPMENT. IF ANY CONVECTION MANAGES TO
DEVELOP IT WILL BE VERY EFFICIENT AT RAIN PRODUCTION. WITH MORE
HUMIDITY AND CLOUDINESS AROUND...HIGH TEMPS WEDNESDAY WILL BE A BIT
LOWER...ESPECIALLY OVER SOUTHWEST ARIZONA AND THE LOWER COLORADO
RIVER VALLEY. ON THURSDAY...DIFFERENCES BETWEEN GFS AND ECMWF BECOME
MORE DISTINCT. ONE KEY AREA IS IN MOISTURE AND CAPE. THE GFS STARTS
TRENDING DOWN WHILE THE ECMWF HANGS ON TO HIGHER VALUES...EVEN THOUGH
THEY HAVE ROUGHLY SIMILAR POSITIONS FOR THE MAIN ANTICYCLONIC AND
CYCLONIC CIRCULATIONS...INCLUDING LINDA. HELD ON TO MODEST POPS AS
UPPER LEVEL WEST-NORTHWESTERLY FLOW LOOKS TO BE FAIRLY CONFLUENT.
FRIDAY THROUGH SUNDAY...
THE FLOW BECOMES MORE AMPLIFIED LATE IN THE WEEK. WITH A NORTHERLY
COMPONENT TO THE FLOW...A DRYING TREND IS EXPECTED. NOT SURPRISINGLY THE
ECMWF IS MORE RELUCTANT TO DRY THINGS OUT. THE POPS DROP OUT FOR MOST
PLACES BY FRIDAY AND EVERYWHERE BY SUNDAY. OF NOTE...AN INVERTED
TROUGH IS ADVERTISED TO MOVE THROUGH NEW MEXICO AND ACROSS NORTHWEST
MEXICO OVER THE WEEKEND. THE GFS KEEPS IT A BIT FURTHER EAST THAN
ECMWF. TAKING A BLENDED APPROACH...AND IN ACKNOWLEDGEMENT OF MUCH OF
THE TEMPERATURE GUIDANCE...NUDGED TEMPS DOWN SLIGHTLY FROM PREVIOUS
PACKAGE. STILL LOOKING AT TEMPERATURES CLIMBING AT LEAST A FEW
DEGREES ABOVE NORMAL...EVEN MORE SO OVER SOUTHWEST ARIZONA AND
SOUTHEAST CALIFORNIA.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
BAND OF SHOWERS WILL CONTINUE TO MOVE NORTH ACROSS THE PHOENIX AREA
THIS AFTERNOON...MOST CIGS SHOULD BE ON THE HIGH SIDE...AOA 12K FEET
OR SO...WITH SOME HIGH BASED CU IN THE AREA AS WELL. SO FAR IT
APPEARS SOMEWHAT STABLE SO THREAT FOR THUNDERSTORMS IS DIMINISHED
AND DUE TO LOW CONFIDENCE NO MENTION OF STORMS WILL BE MADE IN THE
CURRENT TAF PACKAGE. SHOULD CONVECTION BECOME MORE INTENSE LATER WE
CAN UDDATE TAFS FOR THE INCREASED THREAT OF THUNDER. OTHERWISE
CONSIDERABLE MID/HIGH CLOUD DECKS EXPECTED THIS EVENING INTO THE
MORNING HOURS TOMORROW WITH BROKEN CIGS AOA 14K LIKELY AFTER
MIDNIGHT. WINDS GENERALLY LIGHT AND DIURNAL NEXT 24 HOURS.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
THREAT FOR SHOWERS/STORMS NEXT 24 HOURS QUITE LOW...MOSTLY AOB 10
PERCENT SO NO MENTION WILL BE MADE IN THE TAFS. MOSTLY LOOKING AT
SCT TO BKN MID/HIGH LEVEL CLOUD DECKS AT TIMES. WINDS ON THE LIGHT
SIDE FAVORING S/SW DIRECTIONS THROUGH TUESDAY AFTERNOON. A FEW
STORMS MAY DEVELOP ALONG THE NRN BAJA SPINE AND TRY TO MOVE INTO
SWRN IMPERIAL COUNTY BUT CONFIDENCE LOW THAT THEY WILL AFFECT THE
KIPL TERMINAL.
BETTER CHANCES FOR SHOWERS OR THUNDERSTORMS AS WE MOVE INTO THE
MIDDLE OF THE WEEK AS TROPICAL MOISTURE FROM LINDA SPREADS INTO THE
AREA FROM THE SOUTH.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
THURSDAY THROUGH MONDAY...SLIGHT THUNDERSTORM CHANCES WILL CONTINUE
AREAS-WIDE THURSDAY...TAPERING OFF TO NEARLY NEGLIGIBLE CHANCES BY
THE WEEKEND. CONFIDENCE IS HIGHER THAT MOISTURE FROM TROPICAL STORM
LINDA WILL SPREAD INTO THE DESERTS FROM THE SOUTH THROUGH MIDWEEK
CAUSING AN INCREASE IN STORM CHANCES...AND A MARKED INCREASE IN
HUMIDITY LEVELS. MINIMUM RH VALUES WILL MOSTLY RANGE BETWEEN 20 AND
30 PERCENT THURSDAY...LOWERING INTO THE TEENS OVER THE WEEKEND.
OVERNIGHT RECOVERIES WILL BE GOOD AT MOST LOCATIONS THROUGH THE
PERIOD. NEAR SEASONAL NORMAL HIGH TEMPERATURES THURSDAY WILL CLIMB
AND BY THE WEEKEND AS THE AIRMASS DRIES WE CAN EXPECT WELL ABOVE
SEASONAL NORMAL READINGS WITH HIGHS REACHING OR EXCEEDING 110
DEGREES OVER THE WESTERN DESERTS OF SOUTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA. WINDS WILL FAVOR A WEST TO SOUTHWEST DIRECTION IN THE
AFTERNOON...WITH THE TYPICAL LIGHT DRAINAGE COMPONENT OVERNIGHT.
&&
&&
.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION IS NOT EXPECTED.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...WATERS
AVIATION...CB
FIRE WEATHER...CB
AREA FORECAST DISCUSSION
NWS TUCSON AZ
1005 AM MST MON SEP 7 2015
.SYNOPSIS...EXPECT SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS THROUGH TUESDAY. A DRYING TREND WILL LIKELY BEGIN
WEDNESDAY...WITH SHOWERS AND THUNDERSTORMS CONFINED MAINLY NEAR THE
EASTERN MOUNTAINS BY THIS WEEKEND. DAYTIME TEMPERATURES WILL
GENERALLY BE WITHIN A FEW DEGREES OF NORMAL THIS WEEK.
&&
.DISCUSSION...A FEW SHOWERS AND THUNDERSTORMS WERE OCCURRING ACROSS
FAR WESTERN PIMA COUNTY AT THIS TIME. THESE SHOWERS/TSTMS APPEAR TO
BE ASSOCIATED WITH A WEAK CYCLONIC CIRCULATION FEATURE OVER THE NRN
GULF OF CALIFORNIA. THERE IS ALSO AN AXIS OF INSTABILITY AS PER SPC
MESOSCALE ANALYSIS THAT EXTENDS FROM SW ARIZONA SEWD INTO WEST
CENTRAL SONORA. A JET STREAK ALSO EXTENDED FROM SOUTH CENTRAL AZ
INTO NRN ARIZONA...WITH THE ONGOING CONVECTION ASSOCIATED WITH THE
RIGHT ENTRANCE REGION OF THE WEAK JET STREAK.
OTHERWISE...MOSTLY SUNNY SKIES PREVAILED ACROSS ERN SECTIONS WITH
PARTLY CLOUDY TO CLOUDY SKIES FROM TUCSON WWD INTO WRN PIMA COUNTY.
07/12Z KTWC SOUNDING TOTAL PRECIP WATER VALUE WAS 1.56 INCHES. THE
SOUNDING DEPICTED A PRONOUNCED WARM LAYER AROUND 400 MB. MODERATE
SWLY FLOW CONTINUED ABOVE 500 MB.
ADDITIONAL SHOWER/TSTM DEVELOPMENT SHOULD OCCUR DURING THE NEXT 1-2
HOURS WEST OF TUCSON IN RESPONSE TO THE DIAGNOSTIC FEATURES NOTED
ABOVE. SEVERAL HRRR SOLUTIONS AND THE 07/12Z WRF-NAM SUGGEST THAT
SHOWERS/TSTMS ELSEWHERE WILL BE LIMITED TO MAINLY NEAR THE MOUNTAINS
THIS AFTERNOON AND EVENING. THE OFFICIAL FORECAST WAS UPDATED FOR
THE ONGOING SHOWERS/TSTMS ACROSS WRN SECTIONS...AND SOME DOWNWARD
POP ADJUSTMENTS WERE MADE MOSTLY FOR THE LOWER ELEVATIONS BASED ON
THE HRRR AND UNIV OF AZ WRF-NAM SOLUTIONS.
AT ANY RATE...ISOLATED TO SCATTERED SHOWERS/TSTMS WILL PREVAIL THIS
AFTERNOON/EVENING FOLLOWED BY A SLIGHT CHANCE OF SHOWERS/TSTMS LATE
TONIGHT. HIGH TEMPS TODAY WILL BE QUITE CLOSE TO TEMPS ACHIEVED
SUN...AND WILL GENERALLY BE WITHIN A FEW DEGS OF NORMAL.
PLEASE REFER TO THE ADDITIONAL SECTIONS FOR FURTHER DETAIL.
&&
.AVIATION...VALID THRU 08/18.
ISOLATED -TSRA/-SHRA WILL OCCUR WEST OF KTUS THIS MORNING. ISOLATED
TO SCATTERED -TSRA/-SHRA WILL THEN OCCUR ELSEWHERE THIS AFTERNOON
AND EVENING. ISOLATED -TSRA/-SHRA SHOULD THEN CONTINUE LATE TONIGHT
INTO TUESDAY MORNING. OTHERWISE...SCATTERED TO OVERCAST CLOUDS
GENERALLY RANGING FROM 10-15K FT AGL AND SURFACE WIND MAINLY LESS
THAN 10 KTS WILL PREVAIL INTO TUESDAY MORNING. AVIATION DISCUSSION
NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL
OCCUR THROUGH WEDNESDAY. A DRYING TREND IS THEN EXPECTED TO BEGIN
THURSDAY...WITH ISOLATED SHOWERS AND THUNDERSTORMS BECOMING LIMITED
TO MAINLY NEAR THE NEW MEXICO BORDER THIS WEEKEND. BRIEF STRONG...
GUSTY AND ERRATIC WINDS WILL OCCUR WITH THE STRONGER THUNDERSTORMS.
OTHERWISE...20-FOOT WINDS WILL BE MAINLY TERRAIN DRIVEN AND LESS
THAN 15 MPH.
&&
.PREV DISCUSSION /320 AM MST/...
TUESDAY...LOW LEVEL SURGE OF MOISTURE CONTINUES UP THE GLFCA AS WITH
TS LINDA W OF THE SRN TIP OF BAJA. ACROSS SE AZ...PW VALUES REMAIN
IN THE 1"-1.50" RANGE WHILE MID-LVL FLOW BECOME A BIT MORE WLY. WILL
MAINTAIN SLIGHT CHANCE TO CHANCE TYPE POPS ACROSS THE AREA.
WEDNESDAY...LOW LEVEL MOISTURE SURGES INTO THE LOWER DESERTS WITH PW
VALUES UP TO AROUND 2" ACROSS SW AZ AND 1.50" ACROSS SE AZ.
INCREASED POPS A BIT OUT IN WRN PIMA COUNTY...BUT LATER SHIFTS WILL
HAVE TO WATCH MODEL TRENDS FOR WEDNESDAY NIGHT PERIOD. THIS IS BASED
ON NEW 06Z NAM RUN WHICH INCREASE ELY FLOW ALOFT OVER THE AREA WED
NIGHT INTO THU MORNING WHILE SWINGING A DISTURBANCE IN FROM THE S.
CONFIDENCE IN THIS SCENARIO IS ON THE LOW SIDE RIGHT NOW.
THURSDAY...UP IN THE AIR AS WEDNESDAY WILL LIKELY DICTATE ON WHAT
WILL BE AROUND TO IMPACT STORM DEVELOPMENT. AGAIN CONFIDENCE IS LOW
FOR THURSDAY...SO WILL MAINTAIN LOW END TYPE POPS FOR NOW.
BASICALLY LOTS OF IFS FOR THE WEDNESDAY/THURSDAY TIME FRAME THUS THE
LOW CONFIDENCE IN THE FORECAST.
FRIDAY INTO SUNDAY...A SIGNIFICANT DOWNTURN IN STORM CHANCES AS FLOW
ALOFT BECOMES MORE NORTHERLY. WILL HOLD ON TO SLIGHT CHANCE POPS FOR
THIS TIME FRAME.
HIGHS THROUGH MOST OF THIS FORECAST CYCLE WILL REMAIN NEAR NORMAL.
HOWEVER WEDNESDAY AND THURSDAY EASILY COULD BE BELOW NORMAL.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
FRANCIS
AREA FORECAST DISCUSSION
NWS ALBANY NY
125 PM EDT MON SEP 7 2015
.SYNOPSIS...
THE HOT WEATHER WILL CONTINUE INTO THE MIDDLE OF THE
WEEK WITH INCREASING HUMIDITY LEVELS. HIGH PRESSURE OVER THE REGION
WILL SHIFT SOUTH AND EAST OVER THE NEXT FEW DAYS. IN THE
MEANTIME...A COLD FRONT WILL GRADUALLY APPROACH FROM THE GREAT LAKES
REGION WITH INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS LATER IN
THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 125 PM EDT...LABOR DAY HAS FEATURED LOTS OF SUNSHINE AND
ABOVE NORMAL TEMPS. HUMIDITY LEVELS ARE STARTING TO CREEP UP TOO
WITH SFC DEWPTS RISING IN THE TO LOWER TO M60S. MOST OF THE CLOUD
COVER HAS BEEN SOME CIRRUS AND FEW-SCT CUMULUS BY THE MTNS...AS
THE CONVECTIVE TEMP ON THE 12Z KALY SOUNDING WAS 91F. THERE IS NOT
A STRONG FORCING MECHANISM FOR ISOLD CONVECTION TODAY. THE BEST
SHOT FOR ANY DEVELOPMENT WOULD BE FROM A LAKE BREEZE OFF ERIE OR
ONTARIO. WE WILL CONTINUE WITH A DRY FCST FOR THE AFTERNOON INTO
THE EARLY EVENING WITH THE SFC HIGH OFF THE NEW ENGLAND
SEABOARD...AND EXTENDING SW INTO THE MID ATLANTIC CORRIDOR IN
CONTROL. THE LATEST HRRR TRENDS ALSO INDICATE A DRY AFTERNOON TOO.
HIGH TEMPS WILL BE 10 TO 15 DEGREES ABOVE NORMAL FOR DAY...WITH
80-85F READINGS FOR THE MTNS...AND U80S TO A FEW L90S IN THE
VALLEY AREAS. SOME RETOOLING OF THE T/TD/RH/APPARENT TEMPS WERE
DONE BASED ON OBSERVATIONS...AND CLOUD COVER BASED ON THE VISIBLE
SATELLITE TRENDS. THE WINDS WILL VARY FROM THE SE TO SW AT 5-15 MPH.
A WEAK COLD FRONT...OR SFC TROUGH WILL APPROACH FROM THE OVERNIGHT
PERIOD INTO TOMORROW.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
FOR TONIGHT EXPECT MILD AND MUGGY CONDITIONS WITH LOWS IN THE MID
60S TO AROUND 70. THE COLD FRONT WILL SLOWLY MOVE FROM THE CENTRAL
GREAT LAKES INTO THE EASTERN GREAT LAKES. IT WILL STILL BE MAINLY
DRY ACROSS THE FA WITH JUST A SLIGHT CHANCE TO LOW CHANCE OF
SHOWERS AND THUNDERSTORMS LATE AT NIGHT ACROSS FAR NORTHWEST
PORTIONS OF THE FA.
ON TUESDAY THE FRONTAL BOUNDARY WILL BE STALLED ACROSS THE EASTERN
GREAT LAKES...SOUTHERN ONTARIO AND SOUTHERN QUEBEC. WHILE MOST OF
THE FA WILL BE DRY EXPECT WIDELY SCATTERED TO SCATTERED SHOWERS
AND THUNDERSTORMS ACROSS THE NORTHERN HALF OF THE FA. ANY
THUNDERSTORM ACTIVITY WILL DIMINISH TUESDAY EVENING WITH ANOTHER
WARM AND MUGGY NIGHT. EXPECT HIGHS ON TUESDAY TO BE IN THE MID 80S
TO LOWER 90S WITH LOWS TUESDAY NIGHT IN THE MID TO UPPER 60S.
FOR WEDNESDAY AND WEDNESDAY NIGHT EXPECT AN INCREASING CHANCE OF
SHOWERS AND THUNDERSTORMS AS THE COLD FRONT MOVES FROM THE EASTERN
GREAT LAKES WEDNESDAY MORNING INTO EASTERN NEW YORK AND SOUTHERN
VERMONT LATE WEDNESDAY NIGHT. PWATS DURING THIS TIME INCREASE TO
1.75 TO 2+ INCHES...ML MUCAPES INCREASE TO 500 TO 1000 J/KG WITH
DEWPOINTS REMAINING MAINLY IN THE 60S. AT THIS TIME NOT EXPECTING
THE THUNDERSTORMS TO BE SEVERE. HOWEVER AS WE GET INTO WEDNESDAY
AND WEDNESDAY NIGHT HEAVY DOWNPOURS WILL BE POSSIBLE WITH ANY
THUNDERSTORMS ESPECIALLY GIVEN THE HIGH PWAT VALUES. HIGHS ON
WEDNESDAY ARE EXPECTED TO BE IN THE MID 80S TO AROUND 90 WITH LOWS
WEDNESDAY NIGHT IN THE MID TO UPPER 60S.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
A PATTERN CHANGE WILL BE UNDERWAY DURING THIS TIME PERIOD...AS THE
RECENT EASTERN NOAM RIDGE PUSHES FURTHER EAST OFF THE COAST...WHILE
AN UPPER LEVEL TROUGH ATTEMPTS TO DEVELOP ACROSS THE NORTHERN
PLAINS/UPPER GREAT LAKES REGION. MODELS EXHIBIT CONSIDERABLE
UNCERTAINTY AS TO HOW THIS PATTERN CHANGE UNFOLDS...WITH THE 00Z/07
GFS AND GEFS REMAINING MORE PROGRESSIVE WITH THE EVOLVING
PATTERN...WHILE THE 00Z/07 ECMWF IS SLOWER AND MUCH MORE AMPLIFIED.
THIS DIFFERENCE IS MOST NOTABLE FOR NEXT WEEKEND...AS THE GFS WOULD
IMPLY A QUICKER PASSAGE OF THE UPPER LEVEL TROUGH...ALONG WITH
SCATTERED RAIN SHOWERS FOR SAT...WHILE THE ECMWF WOULD IMPLY ENERGY
HOLDING BACK AND POTENTIALLY CARVING OUT A POSSIBLE CLOSED MID LEVEL
LOW CENTER WHICH COULD BRING A POSSIBLE WIDESPREAD STEADY RAINFALL
FOR NEXT SUNDAY...ALONG WITH MUCH BELOW NORMAL TEMPS. FOR NOW...HAVE
SIDED A BIT CLOSER TO THE GFS/GEFS SIDE FOR CONTINUITY...BUT TRENDS
WILL NEED TO BE WATCHED AS WE GET CLOSER TO NEXT WEEKEND.
HERE ARE SOME SPECIFICS...
THU-THU NT...MOST LONG TERM GUIDANCE SUGGEST THAT THE HIGHEST
PROBABILITY OF SHOWERS/THUNDERSTORMS WOULD BE DURING THIS TIME
PERIOD AS A POSSIBLE LEAD UPPER LEVEL IMPULSE AND ASSOCIATED COLD
FRONT SLOWLY MOVE ACROSS FROM THE WEST/NORTHWEST. THERE COULD BE
MULTIPLE WAVES OF LOW PRESSURE ALONG THIS FRONT AS IT MOVES THROUGH.
IT APPEARS THAT WIDESPREAD SHOWERS...ALONG WITH SOME EMBEDDED
THUNDERSTORMS WILL BE LIKELY THU...WITH SHOWERS PERSISTING INTO THU
NT. LOCALLY HEAVY RAINFALL COULD OCCUR...AS PWAT/S POTENTIALLY REACH
INTO THE 1.75-2 INCH RANGE. IT SHOULD BE HUMID...WITH MAX TEMPS HELD
DOWN TO TO CLOUDS AND SHOWERS...MAINLY IN THE UPPER 70S-LOWER 80S IN
VALLEYS...AND LOWER 70S ACROSS HIGHER TERRAIN. SLIGHTLY WARMER TEMPS
COULD OCCUR IN SOME LOWER ELEVATIONS SHOULD THE FRONT AND ASSOCIATED
CLOUDS/RAIN BE DELAYED. THU NT/FRI AM MINS SHOULD FALL INTO THE
LOWER/MID 60S FOR LOWER ELEVATIONS...AND 55-60 ACROSS HIGHER
ELEVATIONS.
FRI-SAT...SHOWERS MAY BE SLOW TO EXIT ON FRI...ESP FOR AREAS E OF
THE HUDSON RIVER...AS THE MID/UPPER LEVEL FLOW REMAINS SOMEWHAT
SOUTHWEST WITH THE RIDGE PERSISTING OFF THE EAST COAST. WILL
THEREFORE KEEP CHC POPS FOR MOST AREAS IN THE MORNING...THEN
DECREASE TO SLIGHT CHC FOR N/W AREAS IN THE AFTERNOON. WILL THEN
SIDE CLOSER TO THE GFS/GEFS FOR FRI NT-SAT...KEEPING SLIGHT CHC
SHOWERS FRI NT...AND MAINLY CHC POPS FOR SCATTERED SHOWERS SAT AS
THE MAIN UPPER TROUGH MOVES THROUGH. EXPECT COOLER TEMPS...WITH FRI
AND SAT MAX TEMPS IN THE 70S FOR VALLEYS...AND 60S ACROSS HIGHER
TERRAIN...ALTHOUGH SHOULD CLOUDS/SHOWERS LINGER ON FRI...EVEN COOLER
TEMPS COULD OCCUR. FRI NT/SAT AM MINS SHOULD FALL INTO THE MID 50S
TO LOWER 60S...WARMEST ACROSS THE MID HUDSON VALLEY AND NW CT.
SAT NT-SUN...THE 00Z/07 GFS WOULD IMPLY A RETURN TO FAIR
WEATHER...WHILE THE 00Z/07 ECMWF WOULD IMPLY CLOUDS AND RAIN
RETURNING DURING SUNDAY...ALONG WITH VERY COOL MAX TEMPS...POSSIBLY
ONLY REACHING THE 60S IN VALLEYS AND 50S ACROSS HIGHER TERRAIN.
AGAIN...HAVE SIDED CLOSER TO THE GFS/GEFS...HOLDING OFF MENTION OF
RAIN AT THIS TIME AND WITH WARMER TEMPS COMPARED TO THE ECMWF...WITH
MAX TEMPS REACHING THE 60S AND 70S. HOWEVER...AS MENTIONED
ABOVE...TRENDS WILL NEED TO BE WATCHED IN CASE UPPER LEVEL ENERGY
GETS HELD BACK AND THEN FORMS INTO AN UPPER LEVEL LOW AS SUGGESTED
BY THE ECMWF...WHICH WOULD IMPLY A MUCH MORE PESSIMISTIC FORECAST
FOR NEXT SUNDAY.
&&
.AVIATION /17Z MONDAY THROUGH FRIDAY/...
HIGH PRESSURE WILL SHIFT OFF THE MID ATLANTIC COAST THROUGH TONIGHT.
A WEAK COLD FRONT WILL APPROACH FROM THE NORTH LATE TUESDAY. ONLY A
FEW CU AND/OR HIGH LEVEL CIRRUS CLOUDS AROUND THIS AFTERNOON AND
EVENING.
FOR TONIGHT...THERE IS A POSSIBILITY OF PATCHY FOG FORMATION AND
MVFR/IFR CONDITIONS AT KPSF AFTER 05Z/TUE...AS SOME WIND MAY KEEP
THE BOUNDARY LAYER JUST MIXED ENOUGH TO PREVENT FOG FROM FORMING.
ELSEWHERE...ENOUGH OF A BREEZE SHOULD PREVENT MUCH FOG FROM
FORMING...WITH VFR CONDITIONS EXPECTED. AFTER 13Z-14Z...ANY FOG
SHOULD BURN OFF AND VFR CONDITIONS SHOULD PREVAIL THROUGH TUESDAY
MORNING.
SOUTH-SOUTHWEST WINDS THIS AFTERNOON AND EVENING AROUND 5-10 KTS.
WINDS WILL DECREASE TO LESS THAN 8 KT THIS EVENING AND CONTINUE
THROUGH THE NIGHT. SOUTH TO SOUTHWEST WINDS ARE EXPECTED AT LESS
THAN 10 KT TUESDAY MORNING.
OUTLOOK...
MON NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
TUE: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA...TSRA.
TUE NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
WED: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA...TSRA.
WED NIGHT-THU: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
THU NIGHT-FRI: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
&&
.FIRE WEATHER...
THE HOT WEATHER WILL CONTINUE INTO THE MIDDLE OF THE WEEK WITH
INCREASING HUMIDITY LEVELS. THE HIGH PRESSURE OVER THE REGION WILL
SHIFT SOUTH AND EAST OVER THE NEXT FEW DAYS. IN THE MEANTIME...A
COLD FRONT WILL GRADUALLY APPROACH FROM THE GREAT LAKES REGION.
RELATIVE HUMIDITIES WILL DROP TO 35 TO 55 PERCENT THIS
AFTERNOON...RECOVER TO 80 TO 100 PERCENT TONIGHT...AND DROP TO 35
TO 55 PERCENT TUESDAY AFTERNOON.
WINDS WILL BE SOUTHWEST TO WEST AT 5 TO 15 MPH TODAY...SOUTHWEST
AT 5 TO 10 MPH TONIGHT AND TUESDAY.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED THE NEXT FEW DAYS. THE RIDGE OF HIGH
PRESSURE OVER THE REGION WILL SHIFT SOUTH AND EAST OVER THE NEXT
FEW DAYS AS A COLD FRONT GRADUALLY APPROACHES FROM THE GREAT LAKES
REGION. MAINLY DRY WEATHER IS EXPECTED UNTIL WEDNESDAY. THE COLD
FRONT IS EXPECTED TO MOVE INTO THEN STALL ACROSS THE REGION LATE
IN THE WEEK BRINGING MUCH NEEDED RAINFALL TO THE AREA. GUIDANCE
INDICATES PWATS SHOULD RISE UP TO ABOUT 2 INCHES AHEAD OF THE
BOUNDARY SO HEAVY DOWNPOURS WOULD BE EXPECTED WITH SOME STORMS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...IAA/WASULA
NEAR TERM...WASULA
SHORT TERM...11
LONG TERM...KL
AVIATION...NAS
FIRE WEATHER...IAA/11
HYDROLOGY...IAA/11
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
331 PM EDT MON SEP 7 2015
.DISCUSSION...
CURRENTLY/TONIGHT...LATEST HRRR HAS HAD A GOOD HANDLE ON
CONVECTIVE DEVELOPMENT THIS AFT WITH SCT-NMRS SHOWER/STORM
COVERAGE NEAR THE TREASURE COAST/BREVARD COUNTY TOWARD THE NRN
INTERIOR/I-4 CORRIDOR. THIS FOCUS FOR STORMS HAS INITIATED FROM A
COMBINATION OF BOUNDARY COLLISIONS AND A MID LEVEL VORT MAX
CROSSING THE REGION. THIS CONVECTIVE ACTIVITY WILL CONTINUE TO
BUILD NORTHWARD WITH ADDITIONAL DEVELOPMENT POSSIBLE ACROSS THE
INTERIOR WHERE SOME BREAKS IN THE HIGHER CLOUD COVER ARE
OCCURRING. A FEW STRONGER STORMS WILL CONTINUE INTO LATE
AFT/SUNSET WITH FREQUENT LIGHTNING...STRONG WIND GUSTS AND LOCALLY
HEAVY RAINFALL POSSIBLE. SOME STORMS HAVE ALSO EXHIBITED ROTATION
THIS AFT THAT COULD PRODUCE ISOLATED FUNNEL CLOUDS.
MODELS INDICATE DECREASING CONVECTION INTO LATE EVENING AND HAVE
RAIN CHANCES ENDING BY MIDNIGHT. LOW LEVEL S/SW FLOW SHOULD KEEP
ANY CONVECTION THAT DEVELOPS OVER THE WATERS OFFSHORE OVERNIGHT.
LOWS EXPECTED IN THE LOW TO MID 70S.
TUE-WED...ABOVE NORMAL RAIN CHANCES CONTINUE TOMORROW AS A MOIST
AIRMASS REMAINS IN PLACE WITH LOW PRESSURE OVER THE EASTERN GULF
LIFTING SLOWLY NORTHWARD. POPS RANGE FROM 50 PERCENT OVER BREVARD
COUNTY/TREASURE COAST UP TO 60-70 PERCENT FARTHER INLAND WHERE
BOUNDARY COLLISIONS ARE MORE LIKELY. RAIN CHANCES THEN DECREASE
WED AS LOW OVER THE GULF RETROGRADES WEST AND DEEPER RIDGE BUILDS
IN FROM THE EAST. DRY MID LEVEL AIR WILL BE DRAWN IN FROM THE
SOUTH-SOUTHWEST WITH LATEST ANALYSIS SHOWING 850-500MB MEAN RH
VALUES AOB 40PCT. WILL KEEP POPS RANGING FROM 20 PERCENT OVER THE
FAR SOUTH TO 30-40 PERCENT NORTH OF OKEECHOBEE COUNTY AND SRN
TREASURE COAST. HIGHS WILL INCREASE FROM UPPER 80S TO AROUND 90
DEG TUE TO LOW 90S OVER MUCH OF THE AREA WED.
THU-SUN...(PREVIOUS DISCUSSION) H30-H20 JET PATTERN EXPECTED TO
AMPLIFY THRU THE LATTER HALF OF THE WEEK AS A 120KT ZONAL JET BTWN
THE ALEUTIANS ISLANDS AND THE KAMCHATKA PENINSULA WORKS ITS WAY
INTO THE PAC NW. THIS WILL ALLOW A WEAK FRONTAL BOUNDARY EXTENDING
FROM THE UPR MID WEST TO THE CENTRAL PLAINS TO DEEP AS IT DRIFTS
INTO THE ERN CONUS.
THE POSITIVE ORIENTATION OF THE TROF AND THE FACT THAT MOST OF THE
JET ENERGY WILL REMAIN WELL N OF THE CANADIAN BORDER SUGGESTS IT
WILL NOT BE ABLE TO UPROOT THE ATLC RIDGE FROM ITS POSITION OVER THE
FL PENINSULA. HOWEVER...IT WILL KEEP ITS AXIS SUPPRESS OVER THE SRN
HALF OF THE PENINSULA...RESULTING INT A DEEP S/SW FLOW PATTERN THRU
THE COLUMN. FCST WILL HAVE HIGHER COASTAL POPS TO REFLECT THIS...
THOUGH AREAS DOWNWIND OF LAKE OKEECHOBEE MAY SEE DIMINISHED POPS
DUE TO THE SHADOW EFFECT. LITTLE CHANGE IN DAY-TO-DAY MAX/MIN TEMPS
AS THE S/SWRLY FLOW KEEPS CENTRAL FL UNDER A SULTRY TROPICAL
AIRMASS.
&&
.AVIATION...TEMPO IFR/MVFR CONDS WITH GREATER COVERAGE OF SHOWERS
AND STORMS NEAR THE BREVARD/TREASURE COASTS AND NRN INTERIOR/I-4
CORRIDOR. STORMS WILL GENERALLY MOVE N/NE BUT NW MOTION ALSO
POSSIBLE NORTH OF ORLANDO. SOME THINNING/BREAKS IN THE HIGHER
CLOUD COVER OVER THE INTERIOR MAY INITIATE ADDITIONAL SCT
SHRA/TSRA THROUGH LATE AFT/SUNSET. DECREASING COVERAGE THEN
EXPECTED INTO THE EVENING WITH VFR CONDS RETURNING FOR THE
OVERNIGHT PERIOD.
&&
.MARINE...
TONIGHT...SE WINDS INCREASE UP TO 10-15 KNOTS OVER THE
WATERS...EAST OF WEAK LOW OVER THE EASTERN GULF. SEAS EXPECTED TO
INCREASE ONLY SLIGHTLY TO 2-3 FEET. MAIN CONCERN WILL CONTINUE TO
BE ANY OFFSHORE MOVING STORMS WITH GUSTY WINDS ALONG THE COAST
THROUGH LATE AFT/SUNSET AND SCATTERED STORMS THAT CAN REDEVELOP
AND MOVE NORTHWARD OVER THE WATERS OVERNIGHT.
TUE-WED...FAVORABLE BOATING CONDITIONS AS THE ATLC RIDGE AXIS
REBUILDS ITSELF OVER THE LCL ATLC IN THE WAKE OF THE DEPARTING LOW
PRES SYSTEM CURRENTLY OVER THE ERN GOMEX. AXIS POSITIONED OVER THE
TREASURE COAST/NRN BAHAMAS SUGGESTS A LIGHT TO GENTLE SRLY FLOW THRU
MIDWEEK...BCMG E/SE NEAR THE COAST IN THE AFTN AS THE EAST COAST SEA
BREEZE DVLPS. SEAS AOB 2FT NEARSHORE AND 2-3FT OFFSHORE.
THU-FRI...A FRONTAL TROF OVER THE UPR MIDWEST/CENTRAL PLAINS WILL
DRIFT INTO THE ERN CONUS ON THU THEN OFF THE ERN SEABOARD ON FRI.
THIS WILL DISPLACE THE ATLC RIDGE TO THE VCNTY OF LAKE OKEECHOBEE...
FORCING SFC/BNDRY LYR WINDS TO VEER TO THE S/SW...GENERALLY AOB
10KTS. SEAS 2FT NEARSHORE AND 2-3FT OFFSHORE THRU THE DAY THU...BCMG
AOB 2FT AREAWIDE ON FRI
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 75 89 75 91 / 40 60 40 40
MCO 74 89 75 92 / 40 60 30 40
MLB 75 90 76 92 / 40 50 30 30
VRB 74 90 75 91 / 40 50 30 30
LEE 75 89 76 92 / 40 60 20 40
SFB 74 90 76 92 / 40 60 30 40
ORL 75 89 76 92 / 40 60 30 40
FPR 75 91 75 92 / 40 50 30 20
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
FORECASTS...WEITLICH
RADAR/IMPACT WX/AVIATION...KELLY
AREA FORECAST DISCUSSION
NWS MIAMI FL
307 PM EDT MON SEP 7 2015
.SHORT TERM (TONIGHT-WEDNESDAY NIGHT)...
A MID LEVEL TROUGH IS CURRENTLY CENTERED OVER THE NORTHEAST GULF
OF MEXICO WITH A SURFACE TROUGH EXTENDING FROM NEAR JAX INTO THE
SOUTHEAST GULF. THIS IS PROVIDING A DEEP SOUTH-SOUTHWEST FLOW OF
TROPICAL AIR INTO SOUTH FLORIDA WITH PWAT JUST OVER 2". THIS ALSO
SET THE STAGE FOR EARLY MORNING THUNDERSTORMS MOVING ONSHORE OF
THE SOUTHWEST COAST EXPANDING ACROSS THE REMAINDER OF THE
PENINSULA INTO EARLY THIS AFTERNOON. AS A RESULT, THE AIRMASS IS
STABILIZING OVER THE LAND AREAS AND HAVE THUS REDUCED THE POPS
SIGNIFICANTLY MOST AREAS. DUE TO THE PROXIMITY OF THE LOW AND COOL
TEMPERATURES ALOFT, CANNOT RULE OUT SOME CONVECTIVE ACTIVITY
THROUGH THE NIGHT ALTHOUGH THE HRRR IS NOT SHOWING MUCH AT ALL.
BOTH THE GFS AND ECMWF SHOW THE LOW SHIFTING TO THE NORTHWEST ON
TUESDAY WITH SOME WARMING AT 500MB AS THE ATLANTIC RIDGE ALSO
SHIFTS BACK TO THE WEST. HOWEVER, AS THIS PATTERN ENFOLDS THE LOW
LEVELS WILL DESTABILIZE WITH INCREASED DIURNAL HEATING BOTH
TUESDAY AND WEDNESDAY. THE FLOW WILL ALSO BACK TO A MORE SOUTH-
SOUTHEAST DIRECTION SO A CONTINUATION OF THE TROPICAL FLOW OF AIR
AND PWAT REMAINING NEAR 2" SO THE CHANCES OF RAIN WILL BE
ELEVATED. THE BACKING STEERING FLOW WILL REVERT THE HIGHEST POPS
FROM THE EAST METRO AREA TO MOSTLY THE INTERIOR SO THE GRIDS WILL
REFLECT THIS PATTERN SHIFT.
.LONG TERM (THURSDAY-MONDAY)...
A DEEP LAYER RIDGE WILL BE THE MAIN INFLUENCE ON SOUTH FLORIDA ON
THURSDAY AND FRIDAY SO MOSTLY SEA BREEZE INTERACTION TYPE
THUNDERSTORM ACTIVITY WILL BE THE PRIMARY PATTERN. OVER THE
WEEKEND AND INTO EARLY NEXT WEEK, THE DIURNAL CYCLE WILL LIKELY
CONTINUE WITH PWAT HOVERING CLOSE TO OR JUST UNDER 2" BUT THE
PATTERN IS A LITTLE UNCERTAIN. BOTH THE GFS AND ECMWF SHOW AN
UPSTREAM MID LEVEL TROUGH WEAKENING THE RIDGE ACROSS SOUTH FLORIDA
BUT THE ECMWF SHOWS A BROADER TROUGH WITH A DEEP SOUTHWESTERLY
FLOW RETURNING. THE GFS ON THE OTHER HAND SHOWS A MORE CLOSED LOW
CIRCULATION AND FARTHER TO OUR NORTH KEEPING THE FLOW MOSTLY
EASTERLY. FOR NOW, WILL SHOW THE HIGHEST POPS OVER THE INTERIOR
AREAS.
&&
.MARINE...
A SOUTH TO SOUTHEAST WIND IS EXPECTED THROUGH THE FORECAST PERIOD
WITH SEAS OF GENERALLY LESS THAN 4 FEET OUTSIDE OF STRONGER
SHOWERS AND THUNDERSTORMS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 78 92 79 92 / 20 40 20 40
FORT LAUDERDALE 79 91 81 91 / 20 40 10 30
MIAMI 78 91 80 92 / 20 40 10 30
NAPLES 77 91 77 91 / 30 50 10 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...30/KOB
LONG TERM....30/KOB
AREA FORECAST DISCUSSION
NWS MIAMI FL
142 PM EDT MON SEP 7 2015
.AVIATION...
CONVECTION IS SLOWING DOWN THIS AFTERNOON. THIS IS IN AGREEMENT
WITH THE SHORT RANGE HRRR MODEL. THERE IS A POTENTIAL FOR
ADDITIONAL CONVECTION THIS AFTERNOON, SO, HAVE A TEMPO FOR A
COUPLE HOURS LONGER, AND VCTS FOR MOST OF THE AFTERNOON, ALTHOUGH
BACKED UP THE CUTOFF TIME BY AN HOUR. DUE TO THE CONVECTION, THE
WINDS HAVE BEEN ERRATIC, AND MAY CONTINUE TO BE SO UNTIL AFTER ALL
THE CONVECTION WINDS DOWN. OTHERWISE, MAINLY VFR CONDITIONS ACROSS
SOUTH FLORIDA, EXCEPT UNDER HEAVY SHOWERS AND THUNDERSTORMS.
&&
.PREV DISCUSSION... /ISSUED 858 AM EDT MON SEP 7 2015/
UPDATE...
LATEST UPDATE CONTAINS MINOR TWEAKS TO MAINLY THE WIND AND SKY
ELEMENTS. THERE ARE SOME LARGER ADJUSTMENTS TO THE POPS ALONG THE
GULF COAST, WHERE A LINE OF SHOWERS AND THUNDERSTORMS ARE MOVING
ONSHORE.
AVIATION...
WITH A WEAK LOW, CENTERED JUST TO THE NORTHWEST, THE FLOW WILL
CONTINUE TO BE SOUTH TO SOUTHEASTERLY. THIS SHOULD HELP TO PUSH
SOME OF THE SHOWERS AND THUNDERSTORMS A LITTLE FURTHER INLAND THAN
YESTERDAY. HOWEVER, THERE IS STILL A CHANCE THEY CAN IMPACT THE
TAF SITES, MAINLY IN THE AFTERNOON HOURS. VFR WILL BE THE
PREDOMINATE FORECAST, HOWEVER, BRIEF IFR IS POSSIBLE UNDER HEAVY
SHOWERS AND THUNDERSTORMS.
PREV DISCUSSION... /ISSUED 316 AM EDT MON SEP 7 2015/
.LATE SUMMER TIME WEATHER PATTERN SETTING UP OVER SOUTH FLORIDA
THIS WEEK...
SHORT TERM...
A MID TO UPPER LEVEL LOW OVER THE NORTHEAST GULF OF MEXICO WILL
MOVE SLOWLY WEST INTO THE NORTHERN CENTRAL GULF OF MEXICO
TODAY...AS HIGH PRESSURE REMAINS OVER THE WESTERN ATLANTIC WATERS.
THIS WILL KEEP A SOUTHERLY WIND FLOW OVER SOUTH FLORIDA TODAY
FOCUSING THE SHOWERS AND THUNDERSTORMS OVER THE NORTHERN AREAS.
HOWEVER...ALL OF SOUTH FLORIDA WILL SEE AT LEAST SCATTERED POPS
TODAY.
THE MID TO UPPER LEVEL LOW WILL CONTINUE TO RETROGRADE WESTWARD
WHILE WEAKENING INTO THE WESTERN GULF OF MEXICO INTO WEDNESDAY...AS
HIGH PRESSURE OVER THE WESTERN ATLANTIC WATERS BUILDS WESTWARD
INTO THE FLORIDA PENINSULA. THIS WILL ALLOW FOR THE WIND FLOW TO
BECOME EASTERLY OVER SOUTH FLORIDA AND BRING IN SOME DRIER AIR TO
THE AREA. THEREFORE...THE HIGHEST POPS WILL SHIFT TO THE WESTERN
AREAS OF SOUTH FLORIDA FOR THE MIDDLE PART OF THE WEEK.
LONG TERM...
THE HIGH WILL REMAIN OVER THE FLORIDA PENINSULA LATE THIS WEEK AND
INTO NEXT WEEKEND...KEEPING THE EASTERLY WIND FLOW OVER SOUTH
FLORIDA. THIS WILL KEEP THE HIGHEST POPS OVER THE WESTERN AREAS OF
SOUTH FLORIDA WITH ONLY ISOLATED TO LOW END SCATTERED POPS OVER
THE EASTERN AREAS OF SOUTH FLORIDA.
AVIATION...
THE WINDS WILL BE SOUTHERLY LESS THAN 5 KNOTS THIS MORNING OVER
THE EAST COAST TAF SITES...BEFORE SWINGING TO A SOUTH SOUTHEAST
DIRECTION AT 5 TO 10 KNOTS THIS AFTERNOON. FOR KAPF TAF SITE...THE
WINDS WILL BE LIGHT AND VARIABLE EARLY THIS MORNING BEFORE
BECOMING WESTERLY AT 5 TO 10 KNOTS THIS MORNING INTO THIS
AFTERNOON. SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE OVER ALL OF
THE TAF SITES AFTER 16Z TODAY. THEREFORE...VCTS WILL REMAIN IN ALL
OF SOUTH FLORIDA TAF SITES FOR THIS AFTERNOON. THE CEILING AND VIS
WILL REMAIN IN THE VFR CONDITIONS AT THIS TIME...DUE TO THE
UNKNOWN TIMING OF THE SHOWERS AND THUNDERSTORMS AFFECTING THE TAF
SITES. HOWEVER...THE CEILING AND VIS SHOULD FALL INTO THE MVFR OR
EVEN IFR CONDITIONS WHEN A SHOWER OR THUNDERSTORM MOVES OVER THE
TAF SITE.
MARINE...
THE WINDS WILL BE SOUTHERLY AT 5 TO 10 KNOTS TODAY BEFORE BACKING
TO AN EAST TO SOUTHEAST DIRECTION TONIGHT THROUGH THE REST OF
THIS WEEK. THIS WILL KEEP THE SEAS AT 2 FEET OR LESS IN BOTH THE
ATLANTIC AND GULF WATERS OF SOUTH FLORIDA THROUGH THIS WEEK.
THEREFORE...BOATING CONDITIONS SHOULD BE GOOD OUTSIDE OF ANY
SHOWERS OR THUNDERSTORMS THIS WEEK OVER SOUTH FLORIDA WATERS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 78 92 79 92 / 40 40 20 20
FORT LAUDERDALE 80 91 81 91 / 30 30 20 20
MIAMI 79 92 80 92 / 20 40 20 20
NAPLES 77 91 77 91 / 20 30 20 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...13/SI
LONG TERM....54/BNB
AVIATION...13/SI
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
651 PM EDT MON SEP 7 2015
.SYNOPSIS...
AN INLAND WEDGE OF HIGH PRESSURE AND A COASTAL TROUGH WILL DISSIPATE
TUESDAY AND TUESDAY NIGHT. ATLANTIC HIGH PRESSURE WILL THEN BUILD
OVER THE SOUTHEAST UNTIL A COLD FRONT APPROACHES THE REGION LATE
THIS WEEK. THE COLD FRONT WILL STALL OVER OR CLOSE TO THE AREA NEXT
WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
DIURNAL CONVECTION WILL DIMINISH THROUGH THE EVENING WITH THE
LOSS OF HEATING. THROUGH THE OVERNIGHT...THE FORECAST AREA WILL
REMAIN ON THE EASTERN PERIPHERY OF A UPPER LOW SITUATED ALONG THE
GULF COAST. LATE IN THE NIGHT...DIFLUENCE WILL INCREASE AND THE
MODELS SHOW A NOTABLE SHORTWAVE MOVING INTO THE AREA FROM THE
SOUTH. AS THE FORCING ALOFT INCREASES...THE MODELS DEPICT A WARM
FRONT LIKE FEATURE LIFTING NORTHWARD WITH INCREASING SHOWER AND
THUNDERSTORM DEVELOPMENT ACCOMPANYING IT. THE MODEL PRECIPITATION
RESPONSE IS PRETTY CONSISTENT AMONGST THE SUITE OF MODELS AND
LENDS CONFIDENCE TO BRINGING IN INCREASING POPS FROM LATE EVENING
ON...MAINLY AT THE COAST AND AREAS SOUTH OF I-16 WHERE SURFACE
MOISTURE FLUX CONVERGENCE WILL BE THE MOST INTENSE. POPS WILL
RANGE FROM 10-20 PERCENT ACROSS THE FAR NORTHWESTERN TIER TO 50-60
PERCENT ALONG PARTS OF THE GEORGIA COAST. A MENTION OF HEAVY RAIN
HAS BEEN ADDED TO THE MOST OF THE GEORGIA COASTAL ZONES GIVEN THE
EXPECTED EFFICIENT RAINFALL RATES WITHIN THE VERY TROPICAL LIKE
ATMOSPHERE.
LOWS WILL BE QUITE SIMILAR TO LAST NIGHT...MAINLY IN THE 70-73
DEGREE RANGE AWAY FROM THE BEACHES. ANOTHER ROUND OF STRATUS
DEVELOPMENT IS EXPECTED TONIGHT AS WELL...AND THERE COULD BE SOME
AREAS THAT SEE LIGHT FOG DEVELOPMENT.
FOR THE EARLY EVENING UPDATE...MADE MINOR ADJUSTMENTS TO HOURLY
POPS TO MATCH GOING KCLX RADAR TRENDS AND TO SPEED UP THE
INTRODUCTION OF LIKELY POPS ACROSS THE FAR SOUTHERN COASTAL ZONES
PER RAP/H3R MODEL OUTPUT.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
THE INLAND WEDGE/COASTAL TROUGH WILL GRADUALLY WEAKEN TUESDAY.
BETWEEN AN UPPER LOW CENTERED WEST OF THE REGION AND AN UPPER RIDGE
BUILDING FROM THE SOUTHEAST...STRENGTHENING/MOIST SOUTHERLY FLOW
WILL CONVERGE/BE FORCED ALOFT BY SURFACE FEATURES OVER THE FORECAST
AREA...AND A WEAK WARM FRONT WILL ADVANCE NORTH THROUGH THE FORECAST
AREA. THIS SCENARIO SHOULD SUPPORT YET ANOTHER WET MORNING ALONG THE
COAST...ESPECIALLY ACROSS CENTRAL/SOUTHERN COASTAL COUNTIES. LIKELY
POPS ARE IN ORDER FOR THESE AREAS TUESDAY MORNING...TAPERED TO
SLIGHT CHANCE/CHANCE FARTHER NORTH/WEST. ALSO...PWATS EXCEEDING 2
INCHES WILL SUPPORT A THREAT FOR LOCALLY HEAVY RAIN. TUESDAY
AFTERNOON...PRECIPITATION COVERAGE BECOMES MORE UNCERTAIN AS THE
INLAND WEDGE/COASTAL TROUGH BECOME ILL-DEFINED...AND THE FOCUS FOR
CONVECTION SHIFTS TO THE SEA BREEZE/CONVECTIVE OUTFLOW BOUNDARIES.
CAPPED MAXIMUM AFTERNOON POPS AT AROUND 50 PERCENT...ESPECIALLY
ACROSS NORTHERN/INLAND COUNTIES...BUT LOCALLY GREATER AMOUNTS COULD
EVENTUALLY BE REQUIRED AS SHORT/NEAR TERM CONVECTIVE TRENDS COME
INTO FOCUS. CLOUDS/PRECIPITATION SHOULD LIMIT INSTABILITY...AND THE
POTENTIAL FOR SEVERE WEATHER REMAINS VERY LOW TUESDAY.
OTHERWISE...HIGH TEMPERATURES IN THE MID/UPPER 80S APPEAR
REASONABLE...HIGHEST SOUTH WHERE PRECIPITATION COVERAGE COULD WANE
DURING THE TIME OF MAX HEATING...ALTHOUGH TEMPERATURES COULD
STRUGGLE TO EXCEED TO THE LOWER 80S IF/WHERE CLOUDS/SHOWERS PERSIST.
TUESDAY NIGHT...POPS OVER LAND SHOULD DIMINISH..AND THE FOCUS FOR
ISOLATED/SCATTERED SHOWERS/THUNDERSTORMS SHOULD SHIFT TO COASTAL
COUNTIES ADJACENT COASTAL WATERS WHERE LOW LEVEL MASS/MOISTURE
CONVERGENCE IS EXPECTED TO DEVELOP. LOW WILL RANGE FROM THE
LOWER/MID 70S INLAND TO THE MID/UPPER 70S AT THE COAST.
WEDNESDAY...HIGH PRESSURE WILL BUILD INTO THE REGION AT THE SURFACE
AND ALOFT. SOUTH/SOUTHWEST FLOW ALOFT BETWEEN THE TROUGH TO THE WEST
AND HIGH PRESSURE CENTERED TO THE EAST/NORTHEAST WILL MAINTAIN A
FLOW OF TROPICAL MOISTURE FEATURING PWATS AROUND 2 INCHES ACROSS THE
REGION. THUS...AT LEAST CHANCE POPS FOR SCATTERED SHOWERS/
THUNDERSTORMS ARE IN ORDER ACROSS THE REGION...ESPECIALLY DURING THE
AFTERNOON AS THE SEA BREEZE ADVANCES INLAND. WHILE ELEVATED PWATS
WILL CONTINUE TO SUPPORT A LOCALIZED THREAT FOR HEAVY
RAIN...STRONGER INSTABILITY AS COMPARED WITH THE PAST FEW DAYS AND 0-
6 KM BULK SHEAR INCREASING TO 15-25 KT SUGGESTS SOME POTENTIAL FOR
MULTICELL CLUSTERS OF THUNDERSTORMS ACCOMPANIED BY A LOW CHANCE FOR
PULSE SEVERE THUNDERSTORMS WITH DAMAGING WIND GUSTS WEDNESDAY
AFTERNOON. MEANWHILE...OUTSIDE ANY THUNDERSTORMS HIGH TEMPERATURES
IN THE UPPER 80S/LOWER 90S SHOULD BECOME COMMON AWAY FROM THE COAST.
WEDNESDAY NIGHT...THE FOCUS FOR ISOLATED/SCATTERED SHOWERS/
THUNDERSTORMS SHOULD ONCE AGAIN SHIFT FROM INLAND COUNTIES TO
COASTAL COUNTIES/ADJACENT COASTAL WATERS. DUE TO UNCERTAINTY
REGARDING THE COVERAGE/IMPACTS OF WEDNESDAY AFTERNOON THUNDERSTORMS
FORECAST LOW TEMPERATURES AGAIN RANGE FROM THE LOWER/MID 70S INLAND
TO THE MID/UPPER 70S AT THE COAST. HOWEVER...A TIGHTENING PRESSURE
GRADIENT AND PERSISTENT WEST/SOUTHWEST WINDS AHEAD OF DEVELOPING PRE-
FRONTAL TROUGH NORTH OF THE REGION COULD HOLD TEMPERATURES IN THE
75-80F RANGE AT LOCATIONS WHERE NO RAIN OCCURS.
THURSDAY...07/12Z MODEL TRENDS SUGGESTS THAT THE REGION WILL REMAIN
POSITIONED BETWEEN ATLANTIC HIGH PRESSURE AND A LEE SIDE TROUGH
NORTH/WEST OF THE FORECAST AREA. THE RESULTING WEST/SOUTHWEST WINDS
AND COMPRESSIONAL HEATING SHOULD SUPPORT ABOVE NORMAL HIGH
TEMPERATURES AT LEAST IN THE LOWER/MID 90S...AND 90F TEMPS COULD
EVEN BE PUSHED TO THE COAST BEFORE THE SEA BREEZE DEVELOPS. MAX HEAT
INDEX VALUES IN THE UPPER 90S/LOWER 100S COULD BE REALIZED THURSDAY
AFTERNOON. ALSO...ISOLATED/SCATTERED THUNDERSTORMS COULD DEVELOP
NEAR THE SEA BREEZE WHICH WILL STRUGGLE TO PUSH INLAND...AND
CLUSTERS OF CONVECTION UPSTREAM COULD PUSH INTO THE REGION
ESPECIALLY INLAND COUNTIES ESPECIALLY LATE. HOWEVER...A SUBTLE
DRYING TREND COULD TRANSLATE TO FEW/NO DIURNAL SHOWERS/
THUNDERSTORMS. MAINTAINED CHANCE POPS INLAND AND SLIGHT CHANCE POPS
ELSEWHERE...ESPECIALLY THURSDAY AFTERNOON...BUT COVERAGE OF
CONVECTION COULD REMAIN SPARSE THURSDAY PM.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
A FAIRLY PROGRESSIVE UPPER PATTERN LATE WEEK THROUGH THE WEEKEND
WILL PUSH A COLD FRONT INTO THE AREA LATE FRIDAY OR SATURDAY. THIS
FRONT IS EXPECTED TO STALL ACROSS SOUTHERN AREAS THROUGH THE
WEEKEND. THE PRIMARY IMPACT WILL BE A SLIGHT INCREASE IN SHOWER AND
TSTM COVERAGE ESPECIALLY ACROSS THE COASTAL WATERS AND SOUTHEAST GA
THOUGH ALL AREAS WILL SEE SOME CONVECTION. DECREASING THICKNESSES
AND GREATER SKY COVER WILL MAINTAIN HIGH TEMPS IN THE UPPER 80S.
&&
.AVIATION /22Z MONDAY THROUGH SATURDAY/...
KCHS...VFR FOR MUCH OF THE PERIOD. MODELS SUGGEST ANY LOW CLOUDS
SHOULD REMAIN WEST OF THE TERMINAL AS THE LOW-LEVEL FLOW VEERS
SOUTHEAST WITH TIME. THERE ARE SIGNALS THAT A BAND OF RAIN COULD
APPROACH THE TERMINAL FROM THE SOUTH BY 14-16Z TUESDAY...BUT
CONFIDENCE IN THIS SCENARIO PANNING OUT THIS FAR OUT IS TOO LOW
TO JUSTIFY A MENTION ATTM.
KSAV...VFR THIS EVENING WITH INCREASING PROBABILITIES FOR MVFR
CIGS/VSBYS AFTER 06Z. MODELS ARE SIMILAR IN SHOWING A LARGE AREA
OF RAIN DEVELOPING ALONG THE NORTHEAST FLORIDA AND FAR SOUTHERN
GEORGIA COAST LATER THIS EVENING...THEN TREKKING NORTH AND
POTENTIALLY IMPACTING THE TERMINAL ROUGHLY 08-11Z. GIVEN THE
SIMILARITIES NOTED IN BOTH THE H3R AND RAP MODELS...WILL GO AHEAD
AND INTRODUCE A TEMPO GROUP DURING THIS TIME FOR 4SM -RA. EXPECT
PREVAILING MVFR CIGS TO DEVELOP BY 07Z AHEAD OF THE RAIN WHICH
WILL LINGER INTO MID-MORNING TUESDAY BEFORE BREAKING OUT. THE
LATEST DATA SUGGEST CIGS WILL REMAIN ABOVE IFR THRESHOLDS...BUT
VSBYS COULD BRIEFLY DROP TO IFR THRESHOLDS IN POCKETS OF HEAVIER
RAINFALL. WILL NO INCLUDE ANY IFR CONDITIONS ATTM.
EXTENDED AVIATION OUTLOOK...OUTSIDE ANY SHOWERS/THUNDERSTORMS VFR
WILL PREVAIL MUCH OF THE TIME.
&&
.MARINE...
TONIGHT...THE PERSISTENT COASTAL TROUGH IS EXPECTED TO BE ALIGNED
RIGHT AT THE COAST THIS EVENING AND THEN GRADUALLY DISSIPATE OR
SHIFT ONSHORE THROUGH THE NIGHT. THE PREVAILING FLOW WILL BE MORE
EASTERLY AND EVENTUALLY SOUTHEASTERLY AS THE NIGHT PROGRESSES. THE
PRESSURE GRADIENT WILL NOT BE AS TIGHT AND WIND SPEEDS ARE EXPECTED
TO TOP OUT IN THE 10-15 KT RANGE...MAINLY FOR THE GEORGIA WATERS
LATE TONIGHT. SEAS WILL BE 2-3 FT...HIGHEST BEYOND 20 NM. SHOWERS
AND STORMS ARE EXPECTED TO INCREASE FROM THE SOUTH LATE TONIGHT AND
COULD PRODUCE LOCALLY HEAVY RAINFALL...REDUCING VISIBILITIES AT
TIMES OVER THE WATERS.
THE INLAND WEDGE/COASTAL TROUGH REGIME WILL GRADUALLY YIELD TO
ATLANTIC HIGH PRESSURE WHICH WILL EXPAND WEST TUESDAY AND WILL
PREVAIL UNTIL LATE WEEK. AS A RESULT...EAST/NORTHWEST WINDS WILL
GIVE WAY TO SOUTHEAST WINDS TUESDAY...THEN WINDS WILL VEER TOWARD
THE SOUTH/SOUTHWEST TUESDAY NIGHT THROUGH FRIDAY. THROUGH
MIDWEEK...WINDS MAINLY 10-15 KT AND SEAS 1-3 FT WILL PREVAIL.
THEN...AHEAD OF AN APPROACHING COLD FRONT THE GRADIENT WILL
TIGHTEN...AND WINDS WILL INCREASE TO 15-20 KT AND SEAS WILL BUILD TO
2-4 FT. WHILE THE PROBABILITY FOR SMALL CRAFT ADVISORY CONDITIONS
WILL INCREASE THROUGH THE LATTER HALF OF THE WEEK...GUIDANCE
MAINTAINS WINDS LESS THAN 25 KT AND SEAS BELOW 6 FT THROUGH THE
PERIOD. THE COLD FRONT WILL ADVANCE IN THE WATERS AND WILL STALL
NEXT WEEKEND...SO WINDS/SEAS REMAIN UNCERTAIN AND WILL DEPEND ON THE
TIMING/POSITION OF THE FRONT.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
ST
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
115 PM EDT MON SEP 7 2015
.SYNOPSIS...
BROAD UPPER LEVEL LOW OVER THE SOUTHEASTERN STATES WILL SHIFT
SOUTHWESTWARD INTO THE GULF OF MEXICO THROUGH TUESDAY AS SURFACE
HIGH PRESSURE BUILDS IN FROM THE NORTH. DEEP AND MOIST FLOW FROM
THE ATLANTIC WILL CONTINUE ACROSS THE REGION. AN UPPER RIDGE WILL
BUILD OVER THE AREA BY MID WEEK BRINGING WARMING TEMPERATURES. A
COLD FRONT AND UPPER TROUGH WILL BRING UNSETTLED WEATHER FOR THE
END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
SURFACE HIGH PRESSURE OVER THE MID-ATLANTIC STATES WILL CONTINUE
TO RIDGE INTO THE CAROLINAS AND GEORGIA THROUGH TONIGHT. BROAD UPPER
LEVEL LOW CENTERED OVER AL/GA BORDER WILL SHIFT SOUTHWESTWARD
INTO THE GULF OF MEXICO. DEEP AND MOIST FLOW FROM THE ATLANTIC
COMBINED WITH WEAK INSTABILITY WILL HOLD THE CHANCE OF SHOWERS AND
THUNDERSTORMS ACROSS THE AREA THOUGH THE EVENING. MOSTLY CLOUDY
SKIES EXPECTED.
SPC HRRR INDICATING SCATTERED CONVECTION PUSHING INTO THE AREA
FROM THE COAST THIS AFTERNOON. CHANCE POPS LOOK REASONABLE FOR
THE AFTERNOON. PRECIPITABLE WATER VALUES GENERALLY AT OR ABOVE 2.0
INCHES SO LOCALLY HEAVY RAIN POSSIBLE. CONVECTION SHOULD WEAKEN
DURING THE EVENING HOURS WITH LOSS OF DAYTIME HEATING.
HIGH TEMPERATURES EXPECTED TO REACH THE MID AND UPPER 80S WITH
LOWS TONIGHT IN THE UPPER 60S TO LOWER 70S.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
WEAK UPPER RIDGING WILL CONTINUE TO EXPAND WESTWARD OVER THE
SOUTHEASTERN STATES FROM THE WESTERN ATLANTIC. A SOUTHEASTERLY
SURFACE FLOW WILL BE BRINGING MOISTURE INTO THE REGION OFF THE
ATLANTIC. PRECIPITABLE WATER VALUES WILL GRADUALLY INCREASE TO
AROUND 2 INCHES BY TUESDAY AFTERNOON AND REMAIN HIGH THROUGH THE
PERIOD AS A DEEPER SOUTH TO SOUTHWESTERLY FLOW PATTERN DEVELOPS
THROUGH THE MID AND UPPER LEVELS OF THE ATMOSPHERE IN RESPONSE TO A
TROUGH MOVING THROUGH THE UPPER MISSISSIPPI AND OHIO VALLEYS.
SEE NO REASON TO CHANGE MUCH WITH THE CURRENT HIGH CHANCE POPS THAT
ARE IN THE CURRENT FORECAST EACH AFTERNOON FOR TUESDAY AND
WEDNESDAY. THERE MAY BE SOME BREAKS IN THE ACTION EACH NIGHT...BUT
WILL CONTINUE WITH SLIGHT CHANCE POPS FOR THE OVERNIGHT HOURS. THE
THREAT OF SEVERE WEATHER REMAIN LOW. BIGGEST ISSUE MAY BE DEALING
WITH PERIODS OF HEAVY RAINFALL IN ANY SLOWER MOVING SHOWERS/STORMS
THAT DEVELOP...ESPECIALLY WITH THE MOIST PROFILES AND WEAK SHEAR.
TEMPERATURES BOTH TUESDAY AND WEDNESDAY WILL WARM UP INTO THE LOWER
90S FOR AFTERNOON HIGHS...AND THE LOWER 70S FOR MORNING LOWS.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
BOTH THE GFS AND ECMWF ADVERTISE A WEAK TROUGH MOVING INTO AND
THROUGH THE REGION ON THURSDAY...WITH THE GFS BEING SLIGHTLY
FASTER BUT NOT BY MUCH. DO EXPECT SCATTERED CONVECTION TO DEVELOP
ACROSS THE REGION IN RESPONSE TO THIS TROUGH PUSHING TOWARDS AND
THROUGH THE AREA ON THURSDAY AFTERNOON/EVENING.
THE MODELS THEN BEGIN TO DIVERGE FROM FRIDAY INTO NEXT WEEK. BOTH
BRING A SECOND DEEPER UPPER TROUGH INTO THE EASTERN UNITED
STATES...BUT THE ECMWF IS MORE AGGRESSIVE AND DEEPER WITH CUTTING
THIS LOW OFF BY SATURDAY MORNING...WHILE THE GFS IS SLOWER IN ITS
MOVEMENT AND TENDS TO KEEP IT AS AN OPEN WAVE SATURDAY. GFS DOES
BEGIN TO CUT THE LOW OFF SATURDAY NIGHT INTO SUNDAY...BUT REMAINS
WEAKER AND FURTHER SOUTH WITH ITS LOW. WITH BOTH SOLUTIONS THE
UPPER FLOW REMAINS SOUTHWESTERLY THROUGH SUNDAY...THEN TURNS
WESTERLY BY MONDAY AS THE UPPER SYSTEM PUSHES OFF THE EAST COAST.
THE SURFACE FRONT ASSOCIATED WITH THE UPPER LOW MOVES CLOSER TO
BUT JUST WEST OF THE REGION THROUGH SATURDAY...BEFORE PUSHING EAST
OF THE AREA SATURDAY NIGHT INTO SUNDAY.
WILL CONTINUE MENTION OF HIGH CHANCE POPS FRIDAY INTO SATURDAY. THEN
BY SUNDAY POPS DIMINISH SOMEWHAT DOWN TO SLIGHT CHANCE/CHANCE
CATEGORY...WITH THE FOCUS OF HIGHER POPS SHIFTING TO THE
SOUTHEASTERN PART OF THE AREA. POPS MAY TREND LOWER NEAR THE END OF
THE PERIOD IF DRIER AIR CAN PUSH FAR ENOUGH INTO THE CWA BY THE
BEGINNING OF NEXT WEEK.
TEMPERATURES DURING THIS PERIOD WILL GENERALLY BE ABOVE NORMAL EARLY
IN THE PERIOD AND NEAR NORMAL OVER THE WEEKEND AND INTO NEXT WEEK.
&&
.AVIATION /17Z MONDAY THROUGH FRIDAY/...
CHANCE FOR SHOWERS WITH ISOLATED THUNDER IN DEEP AND MOIST
EASTERLY FLOW GIVEN WEAK INSTABILITY. THE BEST CHANCE SOUTH AND
EAST...FROM OGB TO AGS/DNL. WILL MENTION VCSH MAINLY FOR THE
AFTERNOON AND EARLY EVENING HOURS. WINDS WILL BE OUT OF THE
NORTHEAST TO EAST AT 10 KNOTS OR LESS. MODELS INDICATING MVFR/IFR
CIGS RETURNING AFTER 08/06Z.
EXTENDED AVIATION OUTLOOK...LATE NIGHT/MORNING FOG/STRATUS
POSSIBLE...WITH A CHANCE OF AFTERNOON SHOWERS AND POSSIBLE
THUNDERSTORMS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
99
AREA FORECAST DISCUSSION
NWS TOPEKA KS
428 PM CDT MON SEP 7 2015
.SHORT TERM...(THIS EVENING THROUGH Tuesday)
ISSUED AT 402 PM CDT MON SEP 7 2015
Showers and isolated storms continued off and on through the
afternoon hours in a zone of 1000-900mb convergence, weak isentropic
lift and the presence of a weak wave. Although the bulk of the
precipitation has moved east into missouri expect isolated to
scattered showers to continue across east central Kansas into the
early evening hours. Further north near the Nebraska border where
few clouds have allowed temperatures to warm into the lower to mid
90s. Latest measoanalysis shows about 40 to 50kts of effective shear,
1500-3000 J/kg of CAPE and no cap in place. Isolated thunderstorms
have developed just to the northwest of the forecast area and were
moving northeast across southern Nebraska at 1930Z. Latest runs of
the HRRR and the RAP suggest further development across north
central Kansas into the evening hours, with additional development
from central Kansas across northeast Kansas through the evening
hours. Storms that can develop across the northern counties may be
severe with hail, strong winds and an isolated tornado possible.
Another round of storms is expected overnight into Tuesday morning
as the upper level trough progresses eastward across the Northern
and Central Plains. Good moisture transport is expected into
northeast Kansas overnight with precipitable water around 2 inches
which will increase the potential for locally heavy rainfall. The
front is expected to move slowly southeast across the forecast area
on Tuesday then moving out of east central Kansas Tuesday evening.
Showers and thunderstorms will likely be ongoing in the morning hours
and then continue along the boundary in the afternoon.
Clouds south of I-70 have kept temperatures in check in the upper
70s to upper 80s. Will likely still see some fluctuations in
temperatures through the late afternoon where the sun can come out.
Tonight, lows should cool into the low to mid 70s with highs on
Tuesday only in the low to mid 80s.
.LONG TERM...(Tuesday NIGHT THROUGH Monday)
ISSUED AT 402 PM CDT MON SEP 7 2015
Cold front and associated showers and thunderstorms should be
moving to the southeast out of east central KS Tuesday evening.
Then surface high pressure builds in with pleasant temperatures
and lower humidities for Wednesday and Wednesday night.
Northwest flow aloft then sets up through the end of the week
with the first in a series of disturbances possibly affecting
north central KS by late Thursday afternoon. That system moves
through Thursday night through Friday with a good chance of
thunderstorms during this time.
Subsidence behind the trough and associated surface high pressure
builds in for Saturday, and an upper ridge builds eastward for
Sunday and Monday, keeping the weekend into Monday dry.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z Tuesday AFTERNOON)
ISSUED AT 1236 PM CDT MON SEP 7 2015
Currently a weak shortwave is still making its way over northeast
KS. A few showers remain to the South of the terminals, but trends
continue in weakening and decreasing coverage. Improvements in
CIGS at KTOP should continue over the next couple hours. The
balance of the afternoon and early evening look VFR at this point.
Confidence into the evening decreases with storm chances once
again in the overall picture. However, coverage and exact timing
are not certain. Have included VCTS in the overnight period again
as the Low Level Jet will still be influencing the terminals and
low- level boundary will still be a factor in the overall forecast
likely through the entire period.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...53
LONG TERM...GDP
AVIATION...Drake
AREA FORECAST DISCUSSION
NWS GOODLAND KS
306 PM MDT MON SEP 7 2015
.SHORT TERM...(THIS AFTERNOON THROUGH TUESDAY)
ISSUED AT 143 PM MDT MON SEP 7 2015
EARLY AFTERNOON WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOWS SW
FLOW IN PLACE ACROSS CENTRAL ROCKIES OVER OUR CWA...AND INTO THE
NORTHERN PLAINS. THIS IS AHEAD OF LARGE UPPER LOW CENTERED OVER
CENTRAL CANADA WITH BROAD TROUGHING EXTENDING SOUTH ACROSS THE
PACIFIC NORTHWEST. CHECKING DYNAMIC TROPOPAUSE...EMBEDDED WEAK
SHORTWAVE TROUGH THAT ROTATED THROUGH REGION THIS MORNING IS NOW
OVER NORTHCENTRAL KS WITH A STRONGER PV HEIGHT ANOMALY ENTERING
CENTRAL COLORADO. SUBSIDENCE BEHIND THE INITIAL FEATURE IS STILL
TRANSITIONING ACROSS MOSTLY OF OUR CWA. AT THE SURFACE A STALLED
FRONT IS JUST SOUTH OF INTERSTATE 70 WITH SURFACE LOW EXTENDING
FROM SOUTHERN COLORADO ACROSS SW KS AND INTO NW KANSAS.
THIS AFTERNOON-TUESDAY...FORCING IS EXPECTED TO INCREASE THIS
EVENING WITH NEXT SHORTWAVE TROUGH MOVING OUT OF THE CENTRAL ROCKIES
AND INTERACTING WITH STALLED FRONTAL ZONE OVER OUR CWA. THERE IS
THE POSSIBILITY FOR OVERRUNNING/BACKBUILDING ALONG ELEVATED FRONTAL
ZONE/STRENGTHENING H7 TROUGH AXIS AS THIS FEATURE MOVES ACROSS THE
REGION. EAST/NORTHEAST FLOW WILL CONTINUE TO ADVECTS BOUNTIFUL
MOISTURE OVER OUR CWA...WITH MODERATE INSTABILITY CONTINUING
THROUGH THE EVENING. CONFIDENCE IS LOWER REGARDING COVERAGE...WITH
FAIRLY LARGE SPREAD IN GUIDANCE SINCE OVERNIGHT AND SUBSIDENCE
INITIALLY IN PLACE OVER OUR CWA. CURRENT ARW/NMM DEPICTS ACTIVITY
INITIATING WEST OF OUR CWA...OR OVER OUR WESTERN CWA AROUND 00Z AND
TRACKING ALONG/NORTH OF FRONT THIS EVENING/OVERNIGHT BEFORE SLOWLY
TRANSITIONING EAST. HRRR/RAP BOTH SUPPORT A SIMILAR LOCATION AND
TIMING...HOWEVER SHOW MUCH LESS IN THE WAY OF COVERAGE. I FELT
COMFORTABLE ADJUSTING THE TIMING TO FAVOR THIS EVENING FOR BEST
COVERAGE AND KEPT MENTION LIMITED TO CHANCE FOR NOW. GUIDANCE SHOWS
BAROCLINIC ZONE LINGERING THROUGH EARLY AFTERNOON TUESDAY ACROSS OUR
SOUTHEAST WITH ADDITIONAL SHOWER/THUNDERSTORM DEVELOPMENT POSSIBLE.
I SHOWED GRADUAL TRANSITION TO THE EAST/SOUTHEAST IN LINE WITH
MODEL CONSENSUS.
REGARDING SEVERE THREAT...HIGH LOW LEVEL MIXING RATIOS HAVE AIDED IN
MODERATE INSTABILITY BUILDING ACROSS OUR CWA WITH ML CAPE 1500-2500
J/KG DEPICTED ON RAP ANALYSIS. DEEP UNIDIRECTIONAL FLOW HAS LED TO
HIGH SHEAR IN MID TO UPPER LEVELS WITH EFFECTIVE SHEER VALUES
ALREADY IN EXCESS OF 50KT OVER OUR CWA. BEST LOW LEVEL SHEAR IS
OVER NORTH CENTRAL KS/NEAR HILL CITY ASSOCIATED WITH VEERING NEAR
WHERE CLOSED SURFACE LOW MAY BE DEVELOPING BASED ON WIND/PRESSURE
FIELD. SEVERE THREAT SHOULD PREDOMINANTLY BE CONFINED TO LARGE
HAIL/DAMAGING WINDS...HOWEVER LOCATIONS IN THE FAR EASTERN PART OF
OUR CWA COULD SEE FAVORABLE CONDITIONS FOR SUPERCELL DEVELOPMENT
AND TORNADO RISK. WINDOW FOR THIS SHOULD BE CONFINED TO THIS
AFTERNOON/EARLY EVENING WITH FRONT TRANSITIONING BACK TO THE
SOUTHEAST THIS EVENING.
RAP/HRRR/NAM/SREF CONTINUE TO SHOW STRATUS/FOG REDEVELOPING ACROSS
NEBRASKA AND ADVECTING/SPREADING SOUTHWEST ACROSS OUR CWA. LOWEST
VIS COULD APPROACH DENSE FOG ADVISORY CRITERIA...THOUGH IT DOES
APPEAR TO BE FAIRLY TRANSIENT REGARDING LOWEST VISIBILITIES. FOR NOW
I KEPT AREAS OF FOG MENTION...AND WILL ALLOW SUBSEQUENT SHIFTS TO
MONITOR NEED FOR NEW DENSE FOG ADVISORY.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 230 PM MDT MON SEP 7 2015
THE WESTERLY FLOW ALOFT ACROSS THE CENTRAL HIGH PLAINS TURNS NORTHWESTERLY
BY THURSDAY AND MORE NORTHERLY BY FRIDAY AND SATURDAY AS THE HIGH
PRESSURE AREA ALOFT OVER NORTHERN MEXICO RETROGRADES AND MERGES
WITH THE HIGH IN THE EASTERN PACIFIC TO FORM A RIDGE OVER THE
WESTERN UNITED STATES WHILE SHORT WAVES EMBEDDED IN THE UPPER
FLOW MOVE THROUGH THE CENTRAL HIGH PLAINS AND INTO THE BASE OF THE
TROUGH DEEPENING IN THE MISSISSIPPI VALLEY REGION. EXPECT ISOLATED
TO SCATTERED SHOWERS AND THUNDERSTORMS FROM WEDNESDAY NIGHT
THROUGH FRIDAY NIGHT AS A RESULT OF THESE DISTURBANCES MOVING
ACROSS THE REGION WITH THE SURFACE FRONTAL BOUNDARY REMAINING
STALLED IN THE VICINITY OF THE FORECAST AREA THROUGH THE END OF
THE WEEK. EXPECT DAYTIME HIGHS MAINLY IN THE 80S WITH LOWS MAINLY
IN THE 50S THROUGH THIS PERIOD.
SOMEWHAT COOLER TEMPERATURES ARE EXPECTED ON FRIDAY AND SATURDAY
WITH DRY CONDITIONS SATURDAY AND SUNDAY IN THE WAKE OF THE
STRONGER SHORT WAVE TROUGH ALOFT AND THE HIGH PRESSURE AREA TO
FOLLOW A COLD FRONT ACROSS THE REGION. SURFACE HIGH PRESSURE MOVES
OUT OF THE FORECAST ARE ON SUNDAY WITH THE LEE TROUGH DEVELOPING
AND TEMPERATURES WARMING AGAIN WITH SOUTHWEST SURFACE FLOW AND THE
WEAKENING RIDGE ALOFT OVER SOUTHWEST U.S. EXTENDING INTO THE
CENTRAL HIGH PLAINS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1145 AM MDT MON SEP 7 2015
LOW STRATUS/CIGS SHOULD INCREASE TO VFR BY THE MIDDLE OF THE
AFTERNOON AT BOTH KGLD AND KMCK. VIS SATELLITE ALREADY SHOWING
BACK EDGE OF STRATUS JUST SW OF KGLD AND THIS SHOULD CONTINUE TO
THE NORTHEAST AS INDICATED BY SHORT RANGE GUIDANCE LOW LEVEL
MOISTURE FIELDS. SHOWERS/THUNDERSTORMS ARE STILL POSSIBLE ACROSS
THE AREA THIS AFTERNOON/EVENING WITH FRONT LINGERING JUST SOUTH OF
KGLD AND ADDITIONAL UPPER LEVEL DISTURBANCES EXPECTED TO MOVE
THROUGH REGION. HIGH RES GUIDANCE SHOWING A LULL IN ACTIVITY THIS
AFTERNOON WITH ACTIVITY INCREASING IN COVERAGE THIS EVENING. AT
THIS POINT CONFIDENCE WAS TOO LOW TO INCLUDE MENTION OF THUNDER
IN TAFS BUT I DID KEEP VCSH IN PLACE.
GUIDANCE SHOWING LOW STRATUS/FOG REDEVELOPING WITH LIGHT
EAST/NORTHEAST FLOW OVER CENTRAL NEBRASKA AND ADVECTING TO THE
SOUTHWEST OVER KMCK THEN KGLD...LINGERING THROUGH MID MORNING.
THERE MAY BE A PERIOD OF LIFR VIS/CIG...HOWEVER CONFIDENCE IN
PREVAILING CONDITIONS IS LEANING TOWARDS IFR VIS (1-2SM)BASED ON
MODEL CONSENSUS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...LOCKHART
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
144 PM MDT MON SEP 7 2015
.SHORT TERM...(THIS AFTERNOON THROUGH TUESDAY)
ISSUED AT 143 PM MDT MON SEP 7 2015
EARLY AFTERNOON WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOWS SW
FLOW IN PLACE ACROSS CENTRAL ROCKIES OVER OUR CWA...AND INTO THE
NORTHERN PLAINS. THIS IS AHEAD OF LARGE UPPER LOW CENTERED OVER
CENTRAL CANADA WITH BROAD TROUGHING EXTENDING SOUTH ACROSS THE
PACIFIC NORTHWEST. CHECKING DYNAMIC TROPOPAUSE...EMBEDDED WEAK
SHORTWAVE TROUGH THAT ROTATED THROUGH REGION THIS MORNING IS NOW
OVER NORTHCENTRAL KS WITH A STRONGER PV HEIGHT ANOMALY ENTERING
CENTRAL COLORADO. SUBSIDENCE BEHIND THE INITIAL FEATURE IS STILL
TRANSITIONING ACROSS MOSTLY OF OUR CWA. AT THE SURFACE A STALLED
FRONT IS JUST SOUTH OF INTERSTATE 70 WITH SURFACE LOW EXTENDING
FROM SOUTHERN COLORADO ACROSS SW KS AND INTO NW KANSAS.
THIS AFTERNOON-TUESDAY...FORCING IS EXPECTED TO INCREASE THIS
EVENING WITH NEXT SHORTWAVE TROUGH MOVING OUT OF THE CENTRAL ROCKIES
AND INTERACTING WITH STALLED FRONTAL ZONE OVER OUR CWA. THERE IS
THE POSSIBILITY FOR OVERRUNNING/BACKBUILDING ALONG ELEVATED FRONTAL
ZONE/STRENGTHENING H7 TROUGH AXIS AS THIS FEATURE MOVES ACROSS THE
REGION. EAST/NORTHEAST FLOW WILL CONTINUE TO ADVECTS BOUNTIFUL
MOISTURE OVER OUR CWA...WITH MODERATE INSTABILITY CONTINUING
THROUGH THE EVENING. CONFIDENCE IS LOWER REGARDING COVERAGE...WITH
FAIRLY LARGE SPREAD IN GUIDANCE SINCE OVERNIGHT AND SUBSIDENCE
INITIALLY IN PLACE OVER OUR CWA. CURRENT ARW/NMM DEPICTS ACTIVITY
INITIATING WEST OF OUR CWA...OR OVER OUR WESTERN CWA AROUND 00Z AND
TRACKING ALONG/NORTH OF FRONT THIS EVENING/OVERNIGHT BEFORE SLOWLY
TRANSITIONING EAST. HRRR/RAP BOTH SUPPORT A SIMILAR LOCATION AND
TIMING...HOWEVER SHOW MUCH LESS IN THE WAY OF COVERAGE. I FELT
COMFORTABLE ADJUSTING THE TIMING TO FAVOR THIS EVENING FOR BEST
COVERAGE AND KEPT MENTION LIMITED TO CHANCE FOR NOW. GUIDANCE SHOWS
BAROCLINIC ZONE LINGERING THROUGH EARLY AFTERNOON TUESDAY ACROSS OUR
SOUTHEAST WITH ADDITIONAL SHOWER/THUNDERSTORM DEVELOPMENT POSSIBLE.
I SHOWED GRADUAL TRANSITION TO THE EAST/SOUTHEAST IN LINE WITH
MODEL CONSENSUS.
REGARDING SEVERE THREAT...HIGH LOW LEVEL MIXING RATIOS HAVE AIDED IN
MODERATE INSTABILITY BUILDING ACROSS OUR CWA WITH ML CAPE 1500-2500
J/KG DEPICTED ON RAP ANALYSIS. DEEP UNIDIRECTIONAL FLOW HAS LED TO
HIGH SHEAR IN MID TO UPPER LEVELS WITH EFFECTIVE SHEER VALUES
ALREADY IN EXCESS OF 50KT OVER OUR CWA. BEST LOW LEVEL SHEAR IS
OVER NORTH CENTRAL KS/NEAR HILL CITY ASSOCIATED WITH VEERING NEAR
WHERE CLOSED SURFACE LOW MAY BE DEVELOPING BASED ON WIND/PRESSURE
FIELD. SEVERE THREAT SHOULD PREDOMINANTLY BE CONFINED TO LARGE
HAIL/DAMAGING WINDS...HOWEVER LOCATIONS IN THE FAR EASTERN PART OF
OUR CWA COULD SEE FAVORABLE CONDITIONS FOR SUPERCELL DEVELOPMENT
AND TORNADO RISK. WINDOW FOR THIS SHOULD BE CONFINED TO THIS
AFTERNOON/EARLY EVENING WITH FRONT TRANSITIONING BACK TO THE
SOUTHEAST THIS EVENING.
RAP/HRRR/NAM/SREF CONTINUE TO SHOW STRATUS/FOG REDEVELOPING ACROSS
NEBRASKA AND ADVECTING/SPREADING SOUTHWEST ACROSS OUR CWA. LOWEST
VIS COULD APPROACH DENSE FOG ADVISORY CRITERIA...THOUGH IT DOES
APPEAR TO BE FAIRLY TRANSIENT REGARDING LOWEST VISIBILITIES. FOR NOW
I KEPT AREAS OF FOG MENTION...AND WILL ALLOW SUBSEQUENT SHIFTS TO
MONITOR NEED FOR NEW DENSE FOG ADVISORY.
.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 240 AM MDT MON SEP 7 2015
FOR THE MAJORITY OF THE LONG TERM...THURSDAY 12Z THROUGH SATURDAY
12Z...THE UPPER LEVEL FLOW IS FAIRLY SIMILAR IN THE GFS AND
EUROPEAN. THERE IS A TROUGH STRETCHING OVER THE GREAT LAKES REGION
AND DOWN INTO THE SOUTHEASTERN STATES...WITH HIGH PRESSURE SITTING
OVER THE WESTERN AND SOUTHWESTERN STATES. AFTER 12Z ON SATURDAY THE
MODELS START TO DIFFER ON HOW THEY HANDLE THE TROUGH IN THE EASTERN
HALF OF THE US. THE GFS STARTS TO PUSH THE TROUGH OUT WHEREAS THE
EUROPEAN HAS THAT TROUGH BECOMING MUCH STRONGER...WITH A CLOSED LOW
AND KEEPS THE TROUGH OVER THE EASTERN REGION. THIS IS SOMETHING TO
KEEP AN EYE ON AS WE GET CLOSER TO THIS COMING WEEKEND.
AS FAR AS PRECIPITATION CHANCES...THURSDAY HAS SOME SLIGHT CHANCES
FOR STORMS OVER THE SOUTHERN AND EASTERN PORTIONS OF THE CWA IN THE
AFTERNOON INTO THE EVENING. GREATER PRECIP CHANCES WILL OCCUR IN THE
EVENING HOURS. SURFACE CAPES ARE SHOWING TO REACH UP TO 2000
J/KG...THE EUROPEAN HAS THE HIGHER CAPE VALUES BUT THE GFS STILL
SHOWS SOME FAIRLY SIGNIFICANT VALUES. BULK SHEAR IS NOT IMPRESSIVE.
FRIDAY HAS THE GREATEST POTENTIAL FOR PRECIPITATION DURING THE
PERIOD. THERE ARE SOME SLIGHT CHANCE POPS FRIDAY AFTERNOON BUT STORM
CHANCES INCREASE FRIDAY EVENING INTO THE OVERNIGHT HOURS. THIS IS
DUE TO A 700MB SHORTWAVE MOVING THROUGH THE CWA IN THE GFS AT 18Z
FRIDAY INTO 06Z SATURDAY...IN ADDITION TO SURFACE CAPE VALUES AROUND
1900 J/KG AND BULK SHEAR REACHING UP TO 50 KTS. THESE STORMS WILL
MOVE OUT FAIRLY QUICK. THE EUROPEAN DOES NOT SHOW THIS SAME
PATTERN...THIS IS LIKELY DUE TO IT STRENGTHENING THE TROUGH IN THE
EASTERN US. THIS IS DEFINITELY SOMETHING TO KEEP AN EYE ON. AS OF
RIGHT NOW...SLIGHT CHANCE AND CHANCE POPS ARE BEING FORECASTED.
SATURDAY AND SUNDAY WILL DRY OUT. THE GFS HAS THE HIGH PRESSURE
STILL DOMINATING IN THE WESTERN STATES AND ZONAL UPPER LEVEL FLOW
STARTING TO FORM OVER THE NORTHWEST. THE EUROPEAN UPPER LEVEL FLOW
IS DIFFERENT BUT STILL SHOWS DRY CONDITIONS. HIGH TEMPERATURES WILL
BE IN THE LOW TO MID 80S EACH DAY. A POSSIBLE SLIGHT TEMPERATURE
DECREASE FRIDAY...IN THE HIGH 70S OVER SOME AREAS...DUE TO THE
PRECIP MOVING INTO THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1145 AM MDT MON SEP 7 2015
LOW STRATUS/CIGS SHOULD INCREASE TO VFR BY THE MIDDLE OF THE
AFTERNOON AT BOTH KGLD AND KMCK. VIS SATELLITE ALREADY SHOWING
BACK EDGE OF STRATUS JUST SW OF KGLD AND THIS SHOULD CONTINUE TO
THE NORTHEAST AS INDICATED BY SHORT RANGE GUIDANCE LOW LEVEL
MOISTURE FIELDS. SHOWERS/THUNDERSTORMS ARE STILL POSSIBLE ACROSS
THE AREA THIS AFTERNOON/EVENING WITH FRONT LINGERING JUST SOUTH OF
KGLD AND ADDITIONAL UPPER LEVEL DISTURBANCES EXPECTED TO MOVE
THROUGH REGION. HIGH RES GUIDANCE SHOWING A LULL IN ACTIVITY THIS
AFTERNOON WITH ACTIVITY INCREASING IN COVERAGE THIS EVENING. AT
THIS POINT CONFIDENCE WAS TOO LOW TO INCLUDE MENTION OF THUNDER
IN TAFS BUT I DID KEEP VCSH IN PLACE.
GUIDANCE SHOWING LOW STRATUS/FOG REDEVELOPING WITH LIGHT
EAST/NORTHEAST FLOW OVER CENTRAL NEBRASKA AND ADVECTING TO THE
SOUTHWEST OVER KMCK THEN KGLD...LINGERING THROUGH MID MORNING.
THERE MAY BE A PERIOD OF LIFR VIS/CIG...HOWEVER CONFIDENCE IN
PREVAILING CONDITIONS IS LEANING TOWARDS IFR VIS (1-2SM)BASED ON
MODEL CONSENSUS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...CLT
AVIATION...DR
AREA FORECAST DISCUSSION
NWS JACKSON KY
132 PM EDT MON SEP 7 2015
.UPDATE...
ISSUED AT 1248 PM EDT MON SEP 7 2015
HOURLY TEMPERATURES ACROSS THE AREA HAVE BEEN RUNNING SEVERAL
DEGREES WARMER SO FAR TODAY THAN THE PREVIOUS FORECAST WAS
DEPICTING. BASED ON THAT AND THE DELAY IN CLOUD FORMATION TODAY
COMPARED TO YESTERDAY...DECIDED TO GO AHEAD AND INCREASE
TEMPERATURES FOR MOST LOCATIONS ACROSS EASTERN KENTUCKY BY A
COUPLE OF DEGREES. ALSO REMOVED OUTDATED WORDING FROM THE ZONE
FORECAST TEXT PRODUCT.
UPDATE ISSUED AT 1015 AM EDT MON SEP 7 2015
UPDATED THE FORECAST TO REMOVE MENTION OF FOG FROM THE TODAY
PERIOD. ALSO UPDATED THE HOURLY GRIDS WITH THE LATEST OBS DATA TO
ESTABLISH NEW TRENDS. WILL NEED TO ISSUE ANOTHER UPDATE IN A
COUPLE OF HOURS TO REMOVE WHAT WILL THEN BE OUTDATED AFTERNOON
WORDING AND ANY OTHER NECESSARY CHANGES.
UPDATE ISSUED AT 730 AM EDT MON SEP 7 2015
HOURLY GRIDS HAVE BEEN UPDATED BASED ON RECENT
OBSERVATIONS...TRENDING DOWN A DEGREE OR TWO IN A FEW VALLEY
LOCATIONS. SFC HIGH PRESSURE WILL BRING MOSTLY DRY WEATHER TO
MUCH OF THE REGION TODAY. VALLEY FOG...DENSE IN SOME
LOCATIONS...WILL DISSIPATE BY AROUND 930 AM. CUMULUS SHOULD BEGIN
TO FORM AROUND NOON AND ISOLATED CONVECTION CANNOT BE RULED OUT.
NEAR TERM MODELS SUCH AS SEVERAL RECENT HRRR RUNS DEVELOP SOME
ISOLATED CONVECTION AROUND 1 PM...MAINLY NEAR THE TN AND VA BORDER
AND ACROSS THE WESTERN PART OF THE CWA. THIS IS IN LINE WITH THE
PREVIOUS FORECAST...SO NO CHANGES WERE MADE WITH THESE.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 350 AM EDT MON SEP 7 2015
THE REGION REMAINS DOMINATED A RIDGE HIGH PRESSURE IN THE LOWER
LEVELS THAT EXTENDS FROM THE OH VALLEY INTO THE ATLANTIC...ALTHOUGH
AT MID LEVELS THE AREA CONTINUES TO RESIDE IN A WEAKNESS BETWEEN
TWO RIDGE CENTERS ONE OVER THE ATLANTIC AND ANOTHER CENTERED OVER
THE SOUTHERN PLAINS. TO THE SOUTH OF THE AREA...A WEAK UPPER LEVEL
RIDGE REMAINS. SKIES HAVE REMAINED CLEAR TO MOSTLY CLEAR OVERNIGHT
AND VALLEY FOG HAS AGAIN FORMED. IT IS LIKELY DENSE NEAR SOME OF
THE AREA RIVERS...OF SHOULD BECOME DENSE PRIOR TO DAWN.
VERY LITTLE CHANCE IS EXPECTED IN THE UPPER PATTERN IS EXPECTED
TODAY ALTHOUGH THE WEAK UPPER LEVEL LOW OVER THE SOUTHEAST SHOULD
DRIFT SOUTHWEST. SOME OF THE MODELS HAVE HEIGHTS RISING A BIT
NORTH OF THE REGION. THE SHORT TERM MODELS GENERATE SOME CONVECTION
ACROSS THE CENTRAL TO WESTERN PARTS OF THE CWA AND NEAR THE VA AND
TN BORDERS IN SOME CASES FROM AROUND MIDDAY INTO THE AFTERNOON.
SSEO CONVECTIVE PROBABILITIES REACH THE 40 TO 60 PERCENT RANGE
ACROSS THE SOUTH AND SOUTHWESTERN PARTS OF THE CWA WITH THIS AREA
EXTENDING NORTH INTO CENTRAL KY FOR THIS AFTERNOON. GIVEN THAT
THIS HAS BEEN A GOOD PREDICTOR OF AREAS OF CONVECTION THE PAST
COUPLE OF DAYS...HAVE OPTED TO GO WITH A SLIGHT CHANCE POP IN THE
AREAS THAT IT HIGHLIGHTS WITH THESE HIGHER PROBABILITIES. WARM MID
LEVEL TEMPS SHOULD LARGELY CAP CONVECTION OVER MOST OF THE
AREA...AND THE VAST MAJORITY OF THE REGION SHOULD REMAIN DRY.
TEMPERATURES SHOULD AGAIN BE ABOVE NORMAL...IN THE UPPER 80S TO
AROUND 90 RANGE OUTSIDE OF THE HIGHEST TERRAIN.
THIS EVENING THROUGH TUESDAY...SFC HIGH PRESSURE SHOULD DOMINATE
AND BE CENTERED TO THE EAST OF THE AREA. HOWEVER...THE MID AND AND
UPPER LEVEL PATTERN SHOULD BEGIN TO CHANGE. THE WEAK UPPER LOW
OVER THE SOUTHEAST SHOULD CONTINUE MEANDERING TO THE SOUTHWEST
WHILE AN UPPER LEVEL LOW MOVES FROM SASKATCHEWAN INTO MANITOBA.
TO THE SOUTH...THE UPPER LEVEL RIDGE INITIALLY CENTERED OVER THE
SOUTHERN PLAINS SHOULD BECOME CENTERED OVER THE RIO GRANDE
VALLEY/NORTHERN MEXICO WHILE A FEW SHORTWAVES MOVING AROUND THIS
RIDGE TRACK FROM THE ROCKIES AND INTO THE PLAINS. THIS WILL LEAD
TO THE BEGINNING OF HEIGHT FALLS OVER THE MID MS VALLEY NORTH INTO
THE WESTERN GREAT LAKES. THIS WILL ALLOW A FRONTAL ZONE TO MOVE
DROP SOUTHEAST INTO THE ST LAWRENCE VALLEY TO CENTRAL GREAT LAKES
TO CENTRAL PLAINS.
ON TUESDAY...THE UPPER LEVEL LOW OVER CANADA SHOULD CONTINUE
TRACKING TO THE EAST NORTHEAST WITH HEIGHTS FALLING OVER THE LOWER
OH VALLEY AS SHORTWAVES MOVE FROM THE PLAINS TOWARD THE GREAT
LAKES. AT THAT POINT...THE UPPER LOW OVER THE GULF OF MEXICO AND
SOUTHEAST SHOULD BEGIN TO MERGE WITH THE TROUGH TO THE NORTH. THE
DEEPEST MOISTURE SHOULD REMAIN TO THE SOUTH OF THE AREA...WITH THE
SOUTHERN AND SOUTHEASTERN FRINGE OF THE AREA THE MOSTLY LIKELY
AREA FOR ANY CONVECTION TO FORM. GREAT CHANCES FOR CONVECTION WILL
HOLD OFF UNTIL THE LONG TERM PERIOD.
AS ALREADY NOTED...SLIGHT CHANCE POPS WERE USED ACROSS THE FAR
WEST AND SOUTH FOR TODAY. ANY CONVECTION AND CU SHOULD DISSIPATE
DURING THE EVENING...WITH DRY WEATHER ALONG WITH SOME PATCHY DENSE
RIVER VALLEY FOG AGAIN POSSIBLE TONIGHT. THIS FOG SHOULD DISSIPATE
WITHIN AN COUPLE OF HOURS AFTER SUNRISE ON TUESDAY. SLIGHT CHANCE
POPS WERE AGAIN USED ACROSS THE FAR SOUTH AND ALONG THE VA BORDER
ON TUESDAY AS DAYTIME HEATING COULD LEAD TO CONVECTION DEVELOPING
ACROSS THAT AREA. IN SUMMARY...BOTH DAYS ARE EXPECTED TO REMAIN
DRY FOR THE VAST MAJORITY OF THE REGION.
ABOVE NORMAL TEMPERATURES SHOULD PERSIST THOUGH THE PERIOD WITH A
MINOR RIDGE/VALLEY SPLIT FOR TONIGHT.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 407 AM EDT MON SEP 7 2015
THE GENERALLY DRY PATTERN AND WARM TEMPERATURES WILL FINALLY COME
TO A END.
THE PERIOD WILL BE MET WITH RIDGING FINALLY BREAKING DOWN ACROSS
THE EAST...AS A TROUGH BEGINS TO APPROACH FROM THE MIDWEST. THAT
SAID MODELS OVERALL IN GOOD AGREEMENT THROUGH MUCH OF THE FIRST
HALF OF THE PERIOD IN TERMS OF UPPER LEVELS. HOWEVER TOWARD THE
END THE AMPLITUDE/STRENGTH OF THE TROUGH COMES INTO
QUESTION...WITH THE 07/00Z ECMWF SHOWING A CUT OFF CENTERED ACROSS
THE GREAT LAKES BY SATURDAY. RIGHT NOW CONFIDENCE REMAINS LOWER
OVERALL ON THIS GIVEN THIS IS THE FIRST RUN TO BE STRENGTHENING
THE 500MB LOW TO THAT EXTENT...AND NONE OF THE OTHER LONG RANGE
MODEL OPERATIONAL RUNS ARE IN LINE WITH THIS THOUGHT. THOUGH MIGHT
BE WORTH NOTING A FEW OF THE ENSEMBLE PERTURBATIONS SEEM TO BE
PAINTING SOMETHING SIMILAR.
AT THE SURFACE THIS PERIOD WILL BE MET WITH BETTER CHANCES OF
WIDESPREAD PRECIP AS COLD FRONT APPROACHES AND MOVES THROUGH THE
REGION. BEST CHANCES RIGHT NOW LOOK TO BE WED AND THU...WITH BEST
UPPER LEVEL SUPPORT BOTH DAYS. MORE UNCERTAINTY EXISTS WITH
SECONDARY COLD FRONT TOWARD THE END OF THE OF THE PERIOD. OVERALL
LOOKS LIKE THIS WILL BE A DRIER FRONT...BUT AFOREMENTIONED CLOSED
LOW ADVERTISED BY THE ECMWF WOULD BRING BETTER CHANCES OF PRECIP
SATURDAY. RIGHT NOW STUCK CLOSER TO THE BLEND GIVEN THE MORE
UNCERTAIN PATTERN.
THE TEMPERATURES WILL CERTAINLY BE WELCOMED WITH HIGHS NEAR TO
BELOW NORMAL. WE WILL ALSO SEE A SOME 50S FOR LOWS BY THE UPCOMING
WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 132 PM EDT MON SEP 7 2015
A RIDGE OF HIGH PRESSURE WILL CONTINUE TO INFLUENCE THE WEATHER OF
EASTERN KENTUCKY DURING THE TAF PERIOD. SCATTERED TO BROKEN LOW
LEVEL CUMULUS CLOUDS WILL PERSIST THROUGH THE REMAINDER OF THE
DAY LIGHT HOURS...BEFORE DISSIPATING QUICKLY AFTER THE SUN GOES
DOWN. ISOLATED SHOWERS AND STORMS ALONG AND WEST OF I-75 THIS
AFTERNOON AND EVENING. SHOWERS AND STORMS WILL BE POSSIBLE ALONG
THE TENNESSEE AND SOUTHWESTERN VIRGINIA BORDERS. THE ISOLATED
NATURE OF THE PRECIPITATION SHOULD KEEP IT OUT OF THE TAF SITES
AND LOZ AND SME. JKL...SYM...AND SJS SHOULD EXPERIENCE ONLY PARTLY
CLOUDY SKIES THROUGH LATE THIS AFTERNOON. WITH CONDITIONS A BIT
WARMER AND DRIER THAN YESTERDAY...FOG SHOULD BE A LITTLE BIT LESS
WIDESPREAD OVERNIGHT. LOZ AND SME MAY STILL SEE SOME FOG DUE TO
ANY RAINFALL THAT OCCURS TODAY WHICH COULD RESULT IN MVFR TO IFR
CONDITIONS AT TIMES LATE TONIGHT. LOZ MAY EVEN SEE BRIEF PERIODS
OF LIFR CIGS AS THE VALLEY FLOOR SATURATES. ASIDE FROM THAT...ANY
FOG SHOULD BE CONFINED TO VALLEYS AND NEAR BODIES OF WATER. WINDS
DURING THE PERIOD WILL BE LIGHT AND VARIABLE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR
SHORT TERM...JP
LONG TERM...DJ
AVIATION...AR
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
105 PM EDT MON SEP 7 2015
...UPDATED AVIATION DISCUSSION...
...FORECAST UPDATE...
ISSUED AT 1130 AM EDT MON SEP 7 2015
THE FORECAST IS ON TRACK FOR THIS AFTERNOON...WITH MAX TEMPS
EXPECTED TO HIT THE LOW TO MID 90S. COMPARED TO 24 HOURS
AGO...READINGS ARE ABOUT 1 TO 2 DEGREES WARMER SO FEEL CONFIDENT
WE`LL HIT THE FORECAST HIGHS.
WITH WEAK SHEAR AXIS OVERHEAD...AND WEAK SHORTWAVE RETROGRADING BACK
INTO SOUTHEAST KENTUCKY...THE SLIGHT CHANCES OF SHOWERS/STORMS LOOK
GOOD. RAP SOUNDINGS ARE SHOWING WARMER MID LEVEL TEMPERATURES
COMPARED TO THE PAST FEW DAYS...WHICH SHOULD KEEP COVERAGE/INTENSITY
TO A MINIMUM.
.SHORT TERM (NOW THROUGH TUESDAY)...
ISSUED AT 235 AM EDT MON SEP 7 2015
THE SYNOPTIC PATTERN EARLY THIS MORNING FEATURES A BROAD RIDGE
ACROSS MUCH OF THE EASTERN CONUS...WITH A VERY BROAD/WEAK LOW
CONTINUING TO SPIN BENEATH THE RIDGE OVER NORTHERN GEORGIA. A SHEAR
AXIS NOTED ON THE NORTHWEST SIDE OF THIS LOW WILL BE THE MAIN FOCUS
TODAY.
LOOKING BACK TO THE CONVECTION YESTERDAY...IT WAS ALL SPARKED WITHIN
THE SHEAR AXIS BETWEEN THE UPPER LOW TO THE SOUTHEAST AND THE
AMPLIFIED RIDGE ACROSS THE GREAT LAKES/MIDWEST REGION. AREAS MAINLY
EAST OF I-65 WILL ONCE AGAIN BE WITHIN THIS SHEAR AXIS TODAY THROUGH
WHICH VERY SUBTLE UPPER-LEVEL WAVES WILL TRAVERSE AS THEY ROTATE
AROUND THE UPPER LOW. FORECAST SOUNDINGS DO SHOW WARM AIR ALOFT
MAINLY AROUND 650-700MB...BUT IT IS NOT ALL THAT MUCH STRONGER THAN
YESTERDAY WHERE WE HAD SOME ISOLATED/WIDELY SCATTERED CONVECTION.
MANY OF THE CAMS ARE ON BOARD WITH THE IDEA OF SOME VERY ISOLATED
ACTIVITY TODAY AND THESE HAVE BEEN LEADING THE CHARGE WITH
CONVECTIVE COVERAGE THE PAST FEW DAYS. THEREFORE...WILL GO WITH 15-
20% COVERAGE WITH THE BEST CHANCES EAST OF I-65 AND SOUTH OF I-64.
LOW-LEVEL THICKNESSES REMAIN VERY SIMILIAR TO WHAT THEY`VE BEEN THE
PAST FEW DAYS...SO BARRING ANY ENHANCED CLOUD COVER FROM
CONVECTION...HIGHS FIRMLY INTO THE 90S LOOK LIKELY AGAIN TODAY.
TONIGHT WILL BE MAINLY CLEAR AND MILD...WITH LOWS IN THE MID 60S TO
LOWER 70S ONCE AGAIN. ON TUESDAY...THE UPPER LOW WILL BECOME LESS
OF A PLAYER AS IT MOVES OFF TO THE SOUTHWEST. ADDITIONALLY...THE
CAPPING TOMORROW LOOKS SUBSTANTIALLY STRONGER THAN IT DOES TODAY.
THEREFORE...WILL GO WITH A DRY FORECAST AND A PERSISTENCE FORECAST
FOR HIGH TEMPERATURES.
.LONG TERM (TUESDAY NIGHT THROUGH SUNDAY)...
ISSUED AT 305 AM EDT MON SEP 7 2015
STILL LOOKING AT A TROUGH MOVING ACROSS THE REGION
WEDNESDAY/WEDNESDAY NIGHT. THE QUESTION IS HOW MUCH PRECIPITATION
WILL MOVE INTO THE REGION WEDNESDAY MORNING AHEAD OF IT. LOOKS LIKE
SOME STORMS WILL FORM OVER MO/IL EARLY WEDNESDAY AND THESE MAY PUSH
INTO OUR NORTHWEST COUNTIES AROUND DAYBREAK. THEY COULD BRING
CLOUDINESS THROUGH THE DAY...DELAYING THE ONSET OF NEW AFTERNOON
STORMS UNTIL LATER IN THE DAY AND BRINGING TEMPERATURES DOWN. SHOULD
THESE STORMS DIE OFF QUICKER THAN IN THIS FORECAST...THEN WE WOULD
SEE A LITTLE WARMER AFTERNOON HIGHS AND AN EARLIER ONSET OF STORM
DEVELOPMENT. FOR NOW WILL CALL FOR AFTERNOON HIGHS IN THE
80S...BREAKING OUR 90+ DEGREE STRING TO START SEPTEMBER. AS FOR
SEVERITY OF THESE STORMS...MODEL WIND FIELDS ARE NOT OVERLY
IMPRESSIVE. THINK THE STRONGER GUSTS WOULD COME WITH THE LATTER
SCENARIO GIVEN ABOVE. WILL CONTINUE TO MENTION BRIEF GUSTY WINDS IN
THE HWO.
ANOTHER WEAKER SHORTWAVE LOOKS TO MOVE THROUGH THE REGION
THURSDAY...CONTINUING THE CHANCE FOR RAIN...WITH THE BEST CHANCE IN
OUR SOUTHEAST. FRIDAY CONTINUES TO TREND DRIER...BUT WITH ANOTHER
WAVE CROSS ING THE REGION CANNOT RULE OUT SOME DEVELOPMENT AT LEAST
EAST OF I-65. AFTER THAT WE SHOULD BE TOO DRY FOR FURTHER
DEVELOPMENT THIS WEEKEND...AND TEMPERATURES WILL BE QUITE
PLEASANT...WITH HIGHS IN THE 70S SATURDAY AND AROUND 80 SUNDAY.
&&
.AVIATION (18Z TAF UPDATE)...
ISSUED AT 105 PM EDT MON SEP 7 2015
PLAN ON VFR CONDITIONS THE REMAINDER OF TODAY AT ALL TAF SITES AS
HIGH PRESSURE AT THE SURFACE AND ALOFT PROVIDES HOT AND DRY
CONDITIONS TO THE AREA. WINDS WILL BE LIGHT/VARIABLE.
FOG WILL ONCE AGAIN BE A THREAT OVERNIGHT...PARTICULARLY AT BWG
WHERE MVFR RESTRICTIONS ARE EXPECTED. LOWER CONDITIONS WILL BE
POSSIBLE IF ISOLATED TO SCATTERED STORMS DEVELOP NEAR THE
TERMINAL...OTHERWISE THINK THAT A DAY OF DRYING SHOULD KEEP
VISIBILITY FROM DROPPING TOO FAR.
FOR TUESDAY...PLAN ON ONE MORE DRY AND HOT DAY FOR THE REGION BEFORE
A PATTERN CHANGE AND SHOWERS/STORMS RETURN MID-WEEK.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
UPDATE.........ZBT
SHORT TERM.....KJD
LONG TERM......RJS
AVIATION.......ZBT
AREA FORECAST DISCUSSION
NWS JACKSON KY
1249 PM EDT MON SEP 7 2015
.UPDATE...
ISSUED AT 1248 PM EDT MON SEP 7 2015
HOURLY TEMPERATURES ACROSS THE AREA HAVE BEEN RUNNING SEVERAL
DEGREES WARMER SO FAR TODAY THAN THE PREVIOUS FORECAST WAS
DEPICTING. BASED ON THAT AND THE DELAY IN CLOUD FORMATION TODAY
COMPARED TO YESTERDAY...DECIDED TO GO AHEAD AND INCREASE
TEMPERATURES FOR MOST LOCATIONS ACROSS EASTERN KENTUCKY BY A
COUPLE OF DEGREES. ALSO REMOVED OUTDATED WORDING FROM THE ZONE
FORECAST TEXT PRODUCT.
UPDATE ISSUED AT 1015 AM EDT MON SEP 7 2015
UPDATED THE FORECAST TO REMOVE MENTION OF FOG FROM THE TODAY
PERIOD. ALSO UPDATED THE HOURLY GRIDS WITH THE LATEST OBS DATA TO
ESTABLISH NEW TRENDS. WILL NEED TO ISSUE ANOTHER UPDATE IN A
COUPLE OF HOURS TO REMOVE WHAT WILL THEN BE OUTDATED AFTERNOON
WORDING AND ANY OTHER NECESSARY CHANGES.
UPDATE ISSUED AT 730 AM EDT MON SEP 7 2015
HOURLY GRIDS HAVE BEEN UPDATED BASED ON RECENT
OBSERVATIONS...TRENDING DOWN A DEGREE OR TWO IN A FEW VALLEY
LOCATIONS. SFC HIGH PRESSURE WILL BRING MOSTLY DRY WEATHER TO
MUCH OF THE REGION TODAY. VALLEY FOG...DENSE IN SOME
LOCATIONS...WILL DISSIPATE BY AROUND 930 AM. CUMULUS SHOULD BEGIN
TO FORM AROUND NOON AND ISOLATED CONVECTION CANNOT BE RULED OUT.
NEAR TERM MODELS SUCH AS SEVERAL RECENT HRRR RUNS DEVELOP SOME
ISOLATED CONVECTION AROUND 1 PM...MAINLY NEAR THE TN AND VA BORDER
AND ACROSS THE WESTERN PART OF THE CWA. THIS IS IN LINE WITH THE
PREVIOUS FORECAST...SO NO CHANGES WERE MADE WITH THESE.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 350 AM EDT MON SEP 7 2015
THE REGION REMAINS DOMINATED A RIDGE HIGH PRESSURE IN THE LOWER
LEVELS THAT EXTENDS FROM THE OH VALLEY INTO THE ATLANTIC...ALTHOUGH
AT MID LEVELS THE AREA CONTINUES TO RESIDE IN A WEAKNESS BETWEEN
TWO RIDGE CENTERS ONE OVER THE ATLANTIC AND ANOTHER CENTERED OVER
THE SOUTHERN PLAINS. TO THE SOUTH OF THE AREA...A WEAK UPPER LEVEL
RIDGE REMAINS. SKIES HAVE REMAINED CLEAR TO MOSTLY CLEAR OVERNIGHT
AND VALLEY FOG HAS AGAIN FORMED. IT IS LIKELY DENSE NEAR SOME OF
THE AREA RIVERS...OF SHOULD BECOME DENSE PRIOR TO DAWN.
VERY LITTLE CHANCE IS EXPECTED IN THE UPPER PATTERN IS EXPECTED
TODAY ALTHOUGH THE WEAK UPPER LEVEL LOW OVER THE SOUTHEAST SHOULD
DRIFT SOUTHWEST. SOME OF THE MODELS HAVE HEIGHTS RISING A BIT
NORTH OF THE REGION. THE SHORT TERM MODELS GENERATE SOME CONVECTION
ACROSS THE CENTRAL TO WESTERN PARTS OF THE CWA AND NEAR THE VA AND
TN BORDERS IN SOME CASES FROM AROUND MIDDAY INTO THE AFTERNOON.
SSEO CONVECTIVE PROBABILITIES REACH THE 40 TO 60 PERCENT RANGE
ACROSS THE SOUTH AND SOUTHWESTERN PARTS OF THE CWA WITH THIS AREA
EXTENDING NORTH INTO CENTRAL KY FOR THIS AFTERNOON. GIVEN THAT
THIS HAS BEEN A GOOD PREDICTOR OF AREAS OF CONVECTION THE PAST
COUPLE OF DAYS...HAVE OPTED TO GO WITH A SLIGHT CHANCE POP IN THE
AREAS THAT IT HIGHLIGHTS WITH THESE HIGHER PROBABILITIES. WARM MID
LEVEL TEMPS SHOULD LARGELY CAP CONVECTION OVER MOST OF THE
AREA...AND THE VAST MAJORITY OF THE REGION SHOULD REMAIN DRY.
TEMPERATURES SHOULD AGAIN BE ABOVE NORMAL...IN THE UPPER 80S TO
AROUND 90 RANGE OUTSIDE OF THE HIGHEST TERRAIN.
THIS EVENING THROUGH TUESDAY...SFC HIGH PRESSURE SHOULD DOMINATE
AND BE CENTERED TO THE EAST OF THE AREA. HOWEVER...THE MID AND AND
UPPER LEVEL PATTERN SHOULD BEGIN TO CHANGE. THE WEAK UPPER LOW
OVER THE SOUTHEAST SHOULD CONTINUE MEANDERING TO THE SOUTHWEST
WHILE AN UPPER LEVEL LOW MOVES FROM SASKATCHEWAN INTO MANITOBA.
TO THE SOUTH...THE UPPER LEVEL RIDGE INITIALLY CENTERED OVER THE
SOUTHERN PLAINS SHOULD BECOME CENTERED OVER THE RIO GRANDE
VALLEY/NORTHERN MEXICO WHILE A FEW SHORTWAVES MOVING AROUND THIS
RIDGE TRACK FROM THE ROCKIES AND INTO THE PLAINS. THIS WILL LEAD
TO THE BEGINNING OF HEIGHT FALLS OVER THE MID MS VALLEY NORTH INTO
THE WESTERN GREAT LAKES. THIS WILL ALLOW A FRONTAL ZONE TO MOVE
DROP SOUTHEAST INTO THE ST LAWRENCE VALLEY TO CENTRAL GREAT LAKES
TO CENTRAL PLAINS.
ON TUESDAY...THE UPPER LEVEL LOW OVER CANADA SHOULD CONTINUE
TRACKING TO THE EAST NORTHEAST WITH HEIGHTS FALLING OVER THE LOWER
OH VALLEY AS SHORTWAVES MOVE FROM THE PLAINS TOWARD THE GREAT
LAKES. AT THAT POINT...THE UPPER LOW OVER THE GULF OF MEXICO AND
SOUTHEAST SHOULD BEGIN TO MERGE WITH THE TROUGH TO THE NORTH. THE
DEEPEST MOISTURE SHOULD REMAIN TO THE SOUTH OF THE AREA...WITH THE
SOUTHERN AND SOUTHEASTERN FRINGE OF THE AREA THE MOSTLY LIKELY
AREA FOR ANY CONVECTION TO FORM. GREAT CHANCES FOR CONVECTION WILL
HOLD OFF UNTIL THE LONG TERM PERIOD.
AS ALREADY NOTED...SLIGHT CHANCE POPS WERE USED ACROSS THE FAR
WEST AND SOUTH FOR TODAY. ANY CONVECTION AND CU SHOULD DISSIPATE
DURING THE EVENING...WITH DRY WEATHER ALONG WITH SOME PATCHY DENSE
RIVER VALLEY FOG AGAIN POSSIBLE TONIGHT. THIS FOG SHOULD DISSIPATE
WITHIN AN COUPLE OF HOURS AFTER SUNRISE ON TUESDAY. SLIGHT CHANCE
POPS WERE AGAIN USED ACROSS THE FAR SOUTH AND ALONG THE VA BORDER
ON TUESDAY AS DAYTIME HEATING COULD LEAD TO CONVECTION DEVELOPING
ACROSS THAT AREA. IN SUMMARY...BOTH DAYS ARE EXPECTED TO REMAIN
DRY FOR THE VAST MAJORITY OF THE REGION.
ABOVE NORMAL TEMPERATURES SHOULD PERSIST THOUGH THE PERIOD WITH A
MINOR RIDGE/VALLEY SPLIT FOR TONIGHT.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 407 AM EDT MON SEP 7 2015
THE GENERALLY DRY PATTERN AND WARM TEMPERATURES WILL FINALLY COME
TO A END.
THE PERIOD WILL BE MET WITH RIDGING FINALLY BREAKING DOWN ACROSS
THE EAST...AS A TROUGH BEGINS TO APPROACH FROM THE MIDWEST. THAT
SAID MODELS OVERALL IN GOOD AGREEMENT THROUGH MUCH OF THE FIRST
HALF OF THE PERIOD IN TERMS OF UPPER LEVELS. HOWEVER TOWARD THE
END THE AMPLITUDE/STRENGTH OF THE TROUGH COMES INTO
QUESTION...WITH THE 07/00Z ECMWF SHOWING A CUT OFF CENTERED ACROSS
THE GREAT LAKES BY SATURDAY. RIGHT NOW CONFIDENCE REMAINS LOWER
OVERALL ON THIS GIVEN THIS IS THE FIRST RUN TO BE STRENGTHENING
THE 500MB LOW TO THAT EXTENT...AND NONE OF THE OTHER LONG RANGE
MODEL OPERATIONAL RUNS ARE IN LINE WITH THIS THOUGHT. THOUGH MIGHT
BE WORTH NOTING A FEW OF THE ENSEMBLE PERTURBATIONS SEEM TO BE
PAINTING SOMETHING SIMILAR.
AT THE SURFACE THIS PERIOD WILL BE MET WITH BETTER CHANCES OF
WIDESPREAD PRECIP AS COLD FRONT APPROACHES AND MOVES THROUGH THE
REGION. BEST CHANCES RIGHT NOW LOOK TO BE WED AND THU...WITH BEST
UPPER LEVEL SUPPORT BOTH DAYS. MORE UNCERTAINTY EXISTS WITH
SECONDARY COLD FRONT TOWARD THE END OF THE OF THE PERIOD. OVERALL
LOOKS LIKE THIS WILL BE A DRIER FRONT...BUT AFOREMENTIONED CLOSED
LOW ADVERTISED BY THE ECMWF WOULD BRING BETTER CHANCES OF PRECIP
SATURDAY. RIGHT NOW STUCK CLOSER TO THE BLEND GIVEN THE MORE
UNCERTAIN PATTERN.
THE TEMPERATURES WILL CERTAINLY BE WELCOMED WITH HIGHS NEAR TO
BELOW NORMAL. WE WILL ALSO SEE A SOME 50S FOR LOWS BY THE UPCOMING
WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 735 AM EDT MON SEP 7 2015
A RIDGE OF HIGH PRESSURE HAS BROUGHT LIGHT WINDS AND MOSTLY CLEAR
TO CLEAR SKIES OVERNIGHT...WHICH HAS SET THE STAGE FOR VALLEY
FOG. THIS FOG HAS BEEN MOST PREVALENT NEAR THE RIVERS AND LAKES.
MVFR FOG GRADUALLY LIFT OUT OF LOZ THROUGH ABOUT 13Z. AT SME...
IFR IF NOT AN INDEFINITE CEILING BELOW THE AIRPORT MIN HAS BEEN
REPORTED. OTHERWISE...SJS AND JKL HAVE BEEN FREE OF FOG WITH SYM
HAVING VIS DOWN TO 7 SM. OTHER NON TAF SITE LOCATIONS SUCH AS
EKQ...W38...1A6...AND I35 WILL INITIALLY BE DOWN TO NEAR OR BELOW
AIRPORT MINS. ALL THE FOG SHOULD LIFT AND DISSIPATE BY 13Z TO 14Z.
A DIURNALLY DRIVEN CU FIELD SHOULD DEVELOP BY AROUND 16Z. AN
ISOLATED SHRA OR TSRA WILL BE POSSIBLE NEAR LOZ AND SME...AS WELL
AS NEARER TO THE VA AND TN BORDERS. CONFIDENCE IN THIS IS TOO LOW
TO INCLUDE IN THE TAF ATTM. OUTSIDE OF ANY CONVECTION VFR SHOULD
DOMINATE FROM 13Z TO 14Z THROUGH AROUND 6Z...WHEN VALLEY FOG WILL
AGAIN FORM. LOZ AND SME MAY EXPERIENCE MVFR OR LOWER FOG AGAIN
NEAR THE END OF THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR
SHORT TERM...JP
LONG TERM...DJ
AVIATION...JP
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
102 PM EDT MON SEP 7 2015
.AVIATION...
COLD FRONT SLOWLY SLIDING INTO SOUTHEAST MICHIGAN THIS AFTERNOON
EXPECTED TO TOUCH OFF SCATTERED SHOWER/THUNDERSTORM ACTIVITY...BUT
PREFERENCE IS TO INCLUDE JUST TEMPO GROUP FOR SHOWERS ACROSS
NORTHERN TAF SITES...UNTIL BETTER HANDLE ON THUNDERSTORM COVERAGE IS
REALIZED. FRONTAL BOUNDARY WILL BE STALLED/NEARLY STATIONARY OVER
THE AREA TONIGHT...AND UPTICK IN SHOWER/THUNDERSTORM ACTIVITY IS
EXPECTED AS LOW LEVEL CONVERGENCE/JET INCREASES A BIT.
HOWEVER...EXACT POSITION OF THIS EXPANDING COVERAGE OF ACTIVITY IS
UNCERTAIN...BUT EXPECTATIONS ARE FOR MIGRATORY NORTHWARD JOG THROUGH
THE NIGHT. OUTSIDE OF THIS ACTIVITY...VFR CEILINGS ARE EXPECTED WITH
LIGHT WINDS (SAVE FOR THIS AFTERNOONS SOUTHWEST WINDS ABOVE 10
KNOTS). FOG WILL LIKELY BECOME AN ISSUE TONIGHT...ESPECIALLY IF
CONVECTIVE ACTIVITY/MID CLOUDS DO NOT PAN OUT...BUT HAVE GONE
MOSTLY CONSERVATIVE (MVFR) FOR NOW.
FOR DTW...THERE REMAINS A LOW CHANCE OF SHOWERS AND THUNDERSTORMS
LATE THIS AFTERNOON INTO EARLY THIS EVENING...BUT HAVE ELECTED TO
INCLUDE THE BETTER CHANCE IN THE TAF TOWARD MIDNIGHT.
FOR DTW...
//DTW THRESHOLD PROBABILITIES...
* LOW CONFIDENCE IN THUNDERSTORMS LATE TODAY THROUGH TOMORROW.
* LOW CONFIDENCE IN CEILINGS AOB 5000 FEET.
&&
.PREV DISCUSSION...ISSUED 1051 AM EDT MON SEP 7 2015
UPDATE...
THE PROSPECTS FOR SHOWERS/THUNDERSTORMS STILL LOOKS TO BE FAIRLY
LOW/SCATTERED COVERAGE EXPECTED TODAY...AS UPPER LEVEL RIDGE (589
DAM AT 500 MB )IN PLACE IS SLOW TO FLATTEN. SURFACE COLD
FRONT/FOLDING OVER MOISTURE PLUME (PW OF 2 INCHES)/850-700 MB THETA-
E RIDGE AXIS WILL PROVIDE FOCUS FOR ACTIVITY...BUT THE FRONT IS
DISPLACED EAST OF THE UPPER LEVEL FORCING...AS 500 MB TEMPS ACTUALLY
LOOK TO RISE TOWARD -6 C TOWARD 00Z TUESDAY. MID LEVEL LAPSE RATES
(700-500 MB) WILL BE WEAK TODAY...BUT ENOUGH MLCAPE (1000-1500 J/KG)
BUILDING TO MAINTAIN THUNDERSTORM THREAT...BUT 0-6 KM BULK SHEAR
GENERALLY AROUND 20 KNOTS...DOES NOT DRAW A HUGE CONCERN FOR
SEVERE WEATHER...BUT VERY HEAVY RAINFALL IS CERTAINTY EXPECTED
WITH ANY STORM. DEEP LAYER UNIDIRECTIONAL WEST-SOUTHWEST WINDS
SHOULD KEEP CELLS MOVING JUST ENOUGH. 12Z NAM AND LATEST RUC BEING
A BIT MORE GENEROUS WITH COVERAGE OVER NORTH HALF OF THE CWA THIS
AFTERNOON...WITH LITTLE OR NO CAP IN THIS MOIST ENVIRONMENT.
HOWEVER...FORECASTED SURFACE DEW PTS LOOK TO BE A TOUCH TOO
HIGH...BUT STILL MAY DECIDE TO NUDGE POPS UP A JUST A
BIT...DEPENDING ON TREND AND FURTHER ANALYSIS.
TEMPERATURES REMAIN ON TRACK TO REACH INTO THE MID/UPPER 80S...WITH
90 DEGREES LIKELY ACROSS EASTERN AREAS...INCLUDING CITY OF DETROIT.
HIGH BASED CLOUDS SHOULD PROVIDE MODEST RELIEF...BUT CERTAINLY HOT
WITH DEW PTS IN 65 TO 70 DEGREE RANGE. INDICATIVE OF THIS HOT AND
MOIST AIRMASS...FLINT AND SAGINAW COULD SET RECORD HIGH MINIMUM
VALUES FOR TODAY (SEPTEMBER 7). SAGINAW LOW THIS MORNING WAS 73
DEGREES...WITH THE RECORD BEING 71 DEGREES SET IN 1985.
MEANWHILE...FLINT BOTTOMED OUT AT 71 DEGREES...WHICH WOULD TIE THE
RECORD HIGH MINIMUM FOR THE DATE...PREVIOUSLY SET IN 2007.
HOWEVER...STILL HAVE POTENTIAL FOR TEMPERATURES TO DROP TOWARD 70
DEGREES BY MIDNIGHT TONIGHT...ESPECIALLY WITH ANY HELP FROM RAIN
COOLED SHOWERS.
PREV DISCUSSION...ISSUED 323 AM EDT MON SEP 7 2015
SHORT TERM...TODAY AND TONIGHT
CONVECTION REMAINS FIRMLY ANCHORED TO ENHANCED SOUTHWESTERLY FLOW
ATTENDANT TO THE LEAD EDGE OF HEIGHT FALLS OVER THE WESTERN AND
NORTHERN GREAT LAKES EARLY THIS MORNING. NWP ADAMANTLY KILL THIS
ACTIVITY DURING THE EARLY MORNING, BUT THETA-E TRANSPORT HAS PROVEN
IMPRESSIVE AND CONVECTION OVER NORTHERN IL/SOUTHERN WI HAS SO FAR
BEEN RESILIENT. THE CORE OF THE LLJ AXIS WITHIN WHICH THIS ACTIVITY
IS EMBEDDED WILL GRADUALLY WEAKEN THROUGH MORNING WHICH DOES SUPPORT
EVENTUAL UPSTREAM DISSIPATION BEFORE THE LLJ FINALLY IMPINGES ON THE
FAR WESTERN CWA AFTER ABOUT 20Z. HOWEVER, DIURNAL HEATING - TEMPERED
BY CONVECTIVE DEBRIS - AND SOME DEGREE OF ONGOING MOISTURE TRANSPORT
WITHIN WEAKER SWLY FLOW OUGHT TO BE SUFFICIENT TO REGENERATE SHOWERS
ALONG THE EASTERN FRINGE OF WHAT REMAINS OF THE ENHANCED
SOUTHWESTERLIES AFTER 18Z. INDEED, PROGGED NAM12 SOUNDINGS DEPICT AN
IMPRESSIVE MOISTENING ABOVE THE LFC WHICH SHOULD HELP GET THINGS
GOING, CONDITIONAL ON SUFFICIENT BOUNDARY LAYER DEEPENING. RECENT
HRRR CYCLES SUPPORT THE IDEA OF REGENERATION AS WELL. LACK OF
INSTABILITY AND SHEAR WILL LIMIT TSTORM POTENTIAL IN GENERAL, BUT
PWATS NEAR 2 INCHES ARE A NOD TO THE PRIMARY THREAT OF HEAVY RAIN
WITH ANYTHING THAT DEVELOPS. THOUGH SENSITIVE TO CONVECTIVE
COVERAGE, HIGHS SHOULD EASILY REACH 90 ACROSS THE FAR EAST, WHILE
THICKER CLOUD COVER EARLIER IN THE DAY IS FORECAST TO LIMIT THE
SAGINAW VALLEY TO THE MID 80S.
RAPID INTENSIFYING OF THE UPPER JET OVER LAKE SUPERIOR WILL ENSUE BY
SEVERAL HOURS AFTER SUNSET MARKING THE ARRIVAL OF MORE VIGOROUS
UPPER ENERGY EMBEDDED WITHIN BROAD CYCLONIC FLOW AROUND THE MANITOBA
CYCLONE. LOWER TROPOSPHERIC FRONTAL ZONE WILL UNDERGO SUBSEQUENT
SHARPENING WHILE A SECONDARY THETA-E SURGE ORGANIZES WITHIN THE
RENEWED LLJ EMERGING OUT OF THE MIDDLE MS VALLEY. THE PRIMARY
UNCERTAINTY DURING THIS TIME IS WHETHER THIS PROCESS WILL ULTIMATELY
SUSTAIN EXISTING/LEFT OVER DIURNAL ACTIVITY OR IF DAYTIME ACTIVITY
WILL WANE COMPLETELY AND GIVE WAY TO SEVERAL HOURS OF DOWN-TIME
BEFORE ISENTROPIC ASCENT RAMPS UP AFTER MIDNIGHT. THIS WILL LIKELY
MAKE ALL THE DIFFERENCE FOR THE DETROIT METRO AREA, AS DISSIPATION
OF DIURNAL ACTIVITY WOULD LIKELY SPELL THE END OF RAIN POTENTIAL FOR
THE EVENING AS FORCING ULTIMATELY REORGANIZES ORGANIZES FURTHER
NORTH ALONG THE M59/I-69 CORRIDOR. CONFIDENCE BY EARLY TUESDAY
MORNING IS HIGHEST IN THE SAGINAW VALLEY WITHIN THE CORRIDOR OF
STRONGEST ASCENT AND DECREASES TOWARD THE THUMB. POPS ARE THEREFORE
TAPERED FROM CATEGORICAL FOR THE FORMER TO ENTRY LEVEL LIKELY FOR
THE LATTER. SKINNY CAPE PROFILE, 2+" PWATS, AND DEVELOPING 12KFT
WARM CLOUD LAYER WILL CERTAINLY SUPPORT AN ENVIRONMENT CAPABLE OF
PROLIFIC HYDROMETEOR PRODUCTION AND RESULTANT HEAVY DOWNPOURS.
ACCORDINGLY, QPF HAS BEEN RAMPED UP TO BASIN AVERAGES OF ABOUT A
HALF INCH AFTER MIDNIGHT. DEPENDING ON COVERAGE, THE POTENTIAL FOR
FURTHER UPWARD ADJUSTMENT WILL EXIST.
LOWS WILL HOVER NEAR 70 FOR YET ANOTHER NIGHT AS HIGH DEWPOINTS PUT
AN A FLOOR ON LOW TEMP POTENTIAL. SOME RELIEF ACROSS THE NORTH WILL
COME IN THE FORM OF RAINFALL, BUT SOUTHERN AREAS WILL REMAIN LARGELY
PRECIP FREE AFTER SUNSET AND WILL BE WARM AND MUGGY ONCE AGAIN.
LONG TERM...
THE LONG TERM WILL FIRST DEAL WITH A LONG DURATION RAINFALL ALONG A
STALLED FRONT...FOLLOWED BY THE INFILTRATION OF A MUCH COOLER
AIRMASS FOR THE WEEKEND.
UPPER LEVEL LOW OVER SOUTHERN CANADA WILL APPROACH WESTERN ONTARIO
TUESDAY MORNING. SEVERAL WEAK SHORTWAVES TRACKING THROUGH THE
LONGWAVE TROUGH AND HEIGHT FALLS ASSOCIATED WITH THE LOW WILL
CONTINUE TO BREAK DOWN THE RIDGE OVER THE EASTERN CONUS. THE FRONT
WILL BE DRAPED ACROSS MID MI BY TUESDAY MORNING WITH THE
PRECIPITATION EVENT WELL ON ITS WAY. A SHORTWAVE IS PROGGED TO LIFT
ALONG THE FRONT EARLY TUESDAY WHICH WILL DEVELOP A SFC LOW NEAR
IOWA. THIS WILL LIFT THE FRONT BACK NORTHWARD TEMPORARILY AS A WARM
FRONT...KEEPING THE HIGHEST POPS ACROSS THE SAGINAW VALLEY. THIS SFC
LOW WILL LIFT NE THROUGH MID MI TUESDAY EVENING WHICH WILL SIGNAL
THE START OF A MORE PROGRESSIVE SYSTEM OVERALL OWNING TO A STRONG
UPPER JET MAX COMING ASHORE BRITISH COLUMBIA MONDAY NIGHT AND
SURGING AROUND THE UPPER LOW. THIS WILL FORCE THE COLD FRONT ACROSS
LOWER MI LATE TUESDAY NIGHT INTO WEDNESDAY MORNING. THIS SYSTEM
OVERALL WILL BE A VERY EFFICIENT RAIN MAKER AS PWATS LOOK TO HOVER
JUST SHY OF 2 INCHES THROUGH THE DURATION OF THE EVENT. STEADY AND
STRONG 850MB LL JET WILL CONTINUALLY FEED MOISTURE NORTHWARD AHEAD
OF THE FRONT. IMPRESSIVE LL THETA E FIELD AS WELL WITH AN ENHANCED
RIBBON OF WARM/MOIST AIR JUST SITTING OVER THE STATE. INSTABILITY
WILL NOT BE TOO GREAT BUT A TALL SKINNY CAPE PROFILE WOULD FAVOR
HEAVY RAINFALL. POPS WILL BE DEPENDENT ON SHORTWAVE
ACTIVITY...PULSES IN THE LL JET...AND FLUCTUATIONS IN THE FRONTAL
BOUNDARY SO GENERALLY SPEAKING...LIKELYS WILL BE FEATURES ACROSS THE
NORTH WITH CHANCE POPS FURTHER SOUTH WITH FUTURE UPDATES PEGGING THE
SMALLER SCALE FORCINGS. SHOWERS WILL DOMINATE BUT SOME
ISOLATED/EMBEDDED THUNDERSTORMS CANNOT BE RULED OUT. BEST CHANCES
FOR THUNDERSTORMS WILL BE WITH THE ACTUAL FROPA WEDNESDAY MORNING.
TEMPERATURES WILL BE TRICKY TUESDAY AS THE FRONTAL LOCATION AND
EXCESSIVE CLOUDS ACROSS THE NORTH WILL LIKELY LEAD TO A HEALTHY
GRADIENT ACROSS SE MI. SHOULD STILL BE ABLE TO GET INTO THE
MID/UPPER 80S ACROSS THE SOUTH AND DETROIT METRO WITH ONGOING
SHOWERS AND CLOUDS KEEPING LOCATIONS FURTHER NORTH CLOSER TO 80 OR
EVEN IN THE UPPER 70S.
PASSAGE OF THE COLD FRONT WILL BRING ABOUT SOME NOTABLE CHANGES
FOR THE REMAINDER OF THE LONG TERM. MUCH COOLER AND DRIER AIR WILL
FEED INTO THE AREA WITH NORTHERLY FLOW. A WAVE DIVING INTO THE BASE
OF THE LONGWAVE TROUGH WILL THEN DEEPEN AND CUTOFF AS IT REACHES THE
GREAT LAKES FOR THE WEEKEND. 850MB TEMPS ARE FORECAST TO FALL BACK
INTO THE SINGLE DIGITS WITH HIGH TEMPERATURES IN THE LOW 70S...AND
POSSIBLY THE UPPER 60S FRIDAY AND SATURDAY. SHOWERS WILL BE POSSIBLE
STARTING FRIDAY NIGHT ASSOCIATED WITH THE BROAD LIFT FROM THE UPPER
LEVEL LOW AND ANY SFC PRESSURE FALLS WITH IT.
MARINE...
SOUTHWESTERLY WINDS WILL BECOME TODAY AHEAD OF AN APPROACHING FRONT.
THIS SLOW MOVING FRONT WILL BRING A CHANCE OF SHOWERS THIS MORNING
FOR NORTHERN LAKE HURON AND LATER THIS AFTERNOON FURTHER SOUTH. A
THUNDERSTORM CANNOT BE RULES OUT BUT NOT EXPECTING ANYTHING STRONG
OR WIDESPREAD. A SURFACE LOW WILL THEN TRACK THROUGH THE AREA LATE
TUESDAY...BRINGING ADDITIONAL SHOWERS AND THUNDERSTORMS THROUGH
EARLY WEDNESDAY. A PERIOD OF GUSTY SOUTHWEST WINDS WILL BE POSSIBLE
ON TUESDAY AS THIS LOW PASSES THROUGH NORTHERN LOWER MICHIGAN. THIS
WILL BE ESPECIALLY TRUE OVER SAGINAW BAY DUE TO FUNNELING.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....SF
UPDATE.......SF
SHORT TERM...JVC
LONG TERM....DRK
MARINE.......DRK
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
336 PM CDT MON SEP 7 2015
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 335 PM CDT MON SEP 7 2015
SHORTWAVE ALOFT IS EVIDENT ON WATER VAPOR ACROSS THE CENTRAL
ROCKIES. THIS WILL MOVE EAST-NORTHEASTWARD ACROSS THE CENTRAL PLAINS
THE NEXT 12 TO 24 HOURS. THUNDERSTORMS STILL ARE POSSIBLE TONIGHT.
THINKING IS THAT STORMS WILL DEVELOP THIS AFTERNOON OVER THE HIGHER
TERRAIN ACROSS COLORADO AHEAD OF THE SHORTWAVE. EXPECTING THAT
STORMS WILL THEN MOVE EAST-NORTHEAST ACROSS MUCH OF THE AREA THIS
EVENING. NOT EVERYONE WILL SEE RAIN...BUT A FAIRLY DECENT COVERAGE
OF STORMS IS POSSIBLE DUE TO FAVORABLE JET DYNAMICS. SEVERE THREAT
IS NOT GREAT DUE TO PERSISTENT CLOUD COVER THAT HAS REMAINED INTACT
AND HAS CUT DOWN ON THE AMOUNT OF INSTABILITY PRESENT ACROSS MUCH OF
THE AREA. BUT...WITH PLENTY OF SHEAR PRESENT...CAN/T RULE OUT A FEW
STRONG OR PERHAPS A SEVERE THUNDERSTORM.
OTHERWISE A COLD FRONT WILL MOVE SOUTHEAST THROUGH THE AREA LATER
TONIGHT USHERING IN COOLER AIR FOR TUESDAY...WITH HIGHS IN THE MID
TO UPPER 70S ACROSS THE AREA. SOME LINGERING MID LEVEL INSTABILITY
WILL BE PRESENT THROUGH TUESDAY MORNING...AND SOME LIFT WILL
CONTINUE THROUGH MIDDAY BEFORE JET DYNAMICS WANE...SO WILL CONTINUE
THE SLIGHT CHANCE FOR SOME MID LEVEL TYPE SHOWER/ISOLATED
THUNDERSTORM ACTIVITY.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 335 PM CDT MON SEP 7 2015
IN THE NEAR TERM TODAY NAM WAS BY FAR THE BEST AT HANDLING ONGOING
PRECIPITATION. LONG RANGE MODELS WERE SLOWER WITH SOLUTIONS IN THE
NEAR TERM. WILL TREND THE FORECAST IN THE MID TERM TOWARDS THE NAM
SOLUTIONS AND A BLEND OF GFS AND ECMWF FOR THE EXTENDED WITH BIAS
TOWARDS WARMER GFS SOLUTIONS AS ECMWF BRINGS A TROUGH AND SUBSEQUENT
CUTOFF LOW INTO THE GREAT LAKES REGION AND AT THE SAME TIME SHEARING
THE HUDSON BAY LOW TO THE NORTHEAST. GFS BRINGS A BROAD TROUGH INTO
THE EASTERN CONUS WHICH SEEMS MORE REASONABLE FOR THE SEASON.
EXTENDED MODELS HAVE BEEN TRYING TO BRING COOLER AIR INTO NORTHERN
PLAINS SINCE LAST WEEK AND HAVE CONTINUED TO TREND UP WITH LATER
RUNS.
TUESDAY EVENING LIGHT SOUTHEAST FLOW AND SURFACE HIGH PRESSURE OVER
HEAD AND FRONT WELL TO THE SOUTH OVER SOUTHERN KANSAS...POSSIBILITY
FOR SOME LIGHT FOG TOWARDS SUNRISE AS TEMPERATURE DEWPOINT SPREAD
DECREASES. HAVE LEFT OUT FOR NOW. WILL TAKE A LOOK ON THE OVER NIGHT
SHIFT TONIGHT WHEN I COME BACK IN. LOWS AROUND 50. SURFACE TROUGH
BUILDS ALONG THE FRONT RANGE ON WEDNESDAY WITH SOUTHWEST FLOW AND
DECENT WAA TEMPERATURES WILL RISE INTO THE LOWER 80S. 25KT 850MB LLJ
WITH MID LEVEL FORCING ALONG THE TROUGH AXIS COULD PRODUCE SOME
ISOLATED CONVECTION THROUGH THE LATE AFTERNOON AND MOVING EAST INTO
THE EVENING AS LLJ INCREASES TO AROUND 50KTS. SOMEWHAT COOLER ON
THURSDAY AS SURFACE HIGH PRESSURE BUILDS INTO WESTERN NEBRASKA.
MODELS FORMING A WEAK SURFACE LOW ALONG STATIONARY BOUNDARY OVER
NORTHWEST KANSAS THROUGH THE DAY FRIDAY INTO SATURDAY MORNING. UPPER
WAVE DROPPING A WAVE THROUGH THE NORTHERN PLAINS AS THE SURFACE LOW
MOVES SOUTHEAST INTO SOUTH CENTRAL KANSAS WITH THE FRONT. SOUTHEAST
ZONES MAY SEE SOME PRECIPITATION BUT WITH THE SURFACE LOW AND THE
FRONT MOVING SOUTHEAST HAVE RETAINED SCHC AFTER MIDNIGHT. RIDGE AND
WARMER AIR BUILDS EAST INTO WESTERN NEBRASKA SATURDAY SUNDAY AND
MONDAY. HIGHS CLIMBING INTO THE MID 80S AND DRY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1248 PM CDT MON SEP 7 2015
VERY DIFFICULT AVIATION FORECAST OVER THE NEXT 24 HOURS FOR THE KLBF
AND KVTN TERMINALS. THE FIRST AREA OF CONCERN/DIFFICULTY IS THE
PERSISTENCE OF LOW CLOUDS OVER THE KLBF TERMINAL...WITH CURRENT
THINKING THAT MVFR CONDITIONS WILL CONTINUE THROUGH THE AFTERNOON
HOURS TODAY. THIS CURRENT THINKING IS SUPPORTED BY THE LATEST RUNS
OF THE RAP/NAM/AND HRRR MODELS...WHICH KEEP CEILINGS AT OR BELOW
3000FT THROUGH 02Z. THE NEXT AREA OF CONCERN/DIFFICULTY WILL BE THE
TIMING ON AFTERNOON/LATE EVENING CONVECTION WITHIN THE GENERAL
VICINITY OF THE KLBF AND KVTN TERMINALS. LATEST OPERATIONAL HRRR HAS
A LINE OF STORMS MOVING INTO THE SOUTHEASTERN PANHANDLE OF NEBRASKA
AND SOUTHWESTERN NEBRASKA BY 00Z THIS EVENING...AND THEN MOVING INTO
THE KLBF TERMINAL BETWEEN 02Z AND 05Z. A SECOND AREA OF CONVECTION
IS ALSO ANTICIPATED TO FORM OVER NORTHWESTERN NEBRASKA BETWEEN 21Z
AND 23Z...BEFORE MOVING EAST INTO THE KVTN TERMINAL BETWEEN 01Z AND
04Z. UNCERTAINTY DOES EXIST WITH SPATIAL COVERAGE OF THIS SECOND
AREA OF CONVECTION NEAR KVTN...HOWEVER...CURRENT CLEARING OVER
NORTHWESTERN NEBRASKA WOULD SUPPORT THE DEVELOPMENT OF THUNDERSTORMS
THIS AFTERNOON.
ANOTHER ROUND OF LOW CLOUDS ARE POSSIBLE TONIGHT AGAIN OVER THE KLBF
TERMINAL AFTER THE AREA OF SHOWERS/THUNDERSTORMS MOVES THROUGH
THIS EVENING. CONFIDENCE IS HIGH ENOUGH AT THIS TIME TO BRING
BACK IN MVFR CONDITIONS OVER THE KLBF TERMINAL...WITH EVEN THE
CHANCE FOR SOME DRIZZLE AFTER 09Z...HOWEVER...THIS WILL BE HIGHLY
DEPENDENT ON HOW MUCH MIXING (WHICH WOULD TEND TO SCOUR OUT THE
MOISTURE) OCCURS IN THE ATMOSPHERE ONCE THIS EVENINGS STORMS MOVE
THROUGH.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...TAYLOR
LONG TERM...POWER
AVIATION...MOLDAN
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1248 PM CDT MON SEP 7 2015
.SYNOPSIS...
ISSUED AT 356 AM CDT MON SEP 7 2015
LARGE UPPER LOW LOCATED OVER SRN CANADA WITH TROUGH AXIS SWD INTO
MT AND ID...WITH NOTABLE PV ANOMALY MOVING THROUGH THE BASE OF
THE TROUGH OVER NRN NV. ZONE OF HIGHER SWRLY FLOW ALOFT LOCATED
AHEAD OF THIS UPPER TROUGH FROM MN TO SRN CA...RUNNING THROUGH
THE NWRN CORNER OF NEB. ALONG THIS SWRLY FLOW ALOFT...WEAK SHORT
WAVES CONTINUE TO PROGRESS QUICKLY NEWD AS THEY HAVE THE PAST FEW
DAYS. SFC FRONT THAT MOVED THROUGH THE AREA THIS MORNING LOCATED
FROM SRN IA ACROSS NERN KS SWWD TO NEAR DDC. THIS FRONT MARKED BY
CONVECTION FROM SRN IA INTO NERN KS. ON THE NORTH SIDE OF THIS
FRONT...ERLY UPSLOPE FLOW EXISTS AT THE SFC WITH NERLY WIND AT
500M/1KM AT KLNX. SFC WINDS HAVE TURNED SERLY ALREADY FROM THE
PANHANDLE INTO NWRN KS AND THIS IS CONTRIBUTING TO TSRA
DEVELOPMENT ACROSS WRN NEB. VSBYS STARTING TO BE REDUCED IN THE
ONL AREA DUE TO FOG.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 356 AM CDT MON SEP 7 2015
FOR THIS MORNING...TSRA DEVELOPING AND MOVING EWD ALONG GRADIENT
OF STEEPER LAPSE RATES ALOFT AND WILL LIKELY BE SUSTAINED AS
ELEVATED INSTABILITY EXPANDS EWD IN INCREASING ISENTROPIC
UPGLIDE. CIRA LOW CLOUD/FOG PRODUCT SHOWING ONLY LIMITED
DEVELOPMENT OF LOW CLOUDS AS EXPECTED BY SHORT RANGE MODELS AND
SREF PROBABILITY GUIDANCE. WILL CONTINUE THE IDEA OF PATCHY FOG
THOUGH CONVECTIVE TRENDS SO FAR WOULD SUGGEST FURTHER FOG
DEVELOPMENT MAY BE INHIBITED SOMEWHAT.
PREVIOUSLY MENTIONED PV ANOMALY OVER NRN NV WILL CONTINUE TO
ROTATE NEWD TODAY AND AS THE ENTIRE TROUGH PULLS EWD...UPPER
LEVEL JET DEVELOPMENT OCCURS IN CONFLUENT ZONE OVER WY TODAY.
THIS WILL PUT THE RIGHT ENTRANCE REGION OF THE NEWLY DEVELOP JET
STREAK OVER WRN NEB BY AFTERNOON. THE RESULTING DIRECT THERMAL
CIRCULATION THAT IS ALREADY DEVELOPING IN RESPONSE OVER THE HIGH
PLAINS...AS EVIDENCED BY ISENTROPIC LIFT ON THE 310/315K
SFC...WILL INDUCE A NWRLY LOW LEVEL AGEOSTROPHIC FLOW AND ENHANCE
FRONTOGENSIS ACROSS THE WRN PORTION OF THE AREA THIS AFTERNOON.
AS THIS OCCURS IN A REGION OF DECENT MID LEVEL INSTABILITY...NEW
TSRA SHOULD DEVELOP THIS AFTERNOON IN WRN NEB AND MOVE EWD. CAPE
IS NOT EXTREME BUT WITH GOOD SHEAR IN PLACE THROUGH A DEEP LAYER
SOME POTENTIAL FOR LARGE HAIL WILL EXIST WITH ANY STORMS THAT DO
DEVELOP...HENCE THE MARGINAL RISK AS DEPICTED BY SPC. THE FLY IN
THE OINTMENT HERE WOULD BE ONGOING CONVECTION AND CONVECTIVE
DEBRIS THAT REMAIN FROM THIS MORNINGS CONVECTION AND HOW THAT
AFFECTS THE ATMOSPHERE BY THIS AFTERNOON. CLOUD COVER MAY
NEGATIVELY AFFECT THE STORMS BEING ABLE TO REALIZE AVAILABLE
CAPE...BUT LEFT OVER BOUNDARIES MAY BE A FOCUS FOR UPWARD
VERTICAL MOTION ENHANCEMENT TO POSITIVELY INFLUENCE INDIVIDUAL
UPDRAFTS...SO ANOTHER COMPLICATED FCST REMAINS. SHORT RANGE
MODELS AND CAM ENSEMBLES AGAIN SUGGEST A WIDE RANGE OF POSSIBLE
SOLUTIONS. ALTHOUGH THE HRRR HAS HAD ITS STRUGGLES LATELY...THINK
IT MIGHT BE ON TO THE RIGHT IDEA DEVELOPING TSRA IN THE 3-4PM CDT
TIME RANGE. THIS IDEA IS ALSO SUPPORTED BY THE NSSL WRF AND BY A
FEW MEMBERS OF THE NCAR 10 MEMBER 3KM WRF ENSEMBLE. THE POPS FCST
IS THEREFORE LIMITED TO THE CHC RANGE FOR NOW.
FOG/LOW CLOUDS MAY BE POSSIBLE AGAIN TONIGHT AND IS SHOWN IN SOME
OF THE MOS GUIDANCE AS WELL AS THE 07.03Z SREF. ULTIMATE
DEVELOPMENT HOWEVER WILL DEPEND ON THE CONVECTIVE TRENDS
OVERNIGHT...SO CONFIDENCE WAS NOT HIGH ENOUGH TO INCLUDE IN THE
FCST AT THIS POINT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 356 AM CDT MON SEP 7 2015
CHILLY TUESDAY WITH LINGERING MORNING SHOWERS GIVING WAY TO
PARTLY SUNNY SKIES. COOL HIGH PRESSURE BUILDS ACROSS THE AREA AND
BATTLE BETWEEN CAA AND SEPTEMBER SUN. THE BIGGEST THING TO WATCH
IS HOW SOON CLOUDS DISSIPATE...WHICH WILL HAVE A DIRECT IMPACT ON
HIGHS. MOST AREAS HOLD IN THE 70S...EXCEPT FOR FAR SW WITH HIGHS
AROUND 80...ALTHOUGH AN EARLIER CLEARING WILL BUMP UP TEMPS A
GOOD 5 DEGREES OR MORE.
BL MOISTURE WILL BE A CONCERN TUESDAY NIGHT INTO WED MORN. THE
NAM WHICH HAS MORE BL MOISTURE SUGGESTS STRATUS/FOG COULD DEVELOP
WITH WINDS BECOMING SOUTHEASTERLY/SOUTHERLY ON THE BACK SIDE OF
THE SFC HIGH. THE GFS/EC MOS GUIDANCE IS DRIER AND KEEPS THINGS
CLEAR AND HAS SLIGHTLY LOWER TEMPS. MODELS HAVE BEEN STRUGGLING
WITH LOW LEVEL MOISTURE...WHICH LEADS TO LOW CONFIDENCE IN
WHETHER FOG/STRATUS WILL DEVELOP OR NOT.
WEDNESDAY WILL SEE THE NEXT WEAK COLD FRONT PUSH ACROSS THE AREA.
SLIGHT WARM UP AHEAD OF THE FRONT WITH MOST HIGHS AROUND 80 INTO
THE MID 80S. MODELS HAVE BEEN IN GOOD AGREEMENT DEVELOPING A LINE
OF STORMS ALONG THE BOUNDARY WHICH MODEL BLENDS PLACE ACROSS THE
HEART /FROM NORTHEAST TO SOUTHWEST/ OF THE CWA DURING PEAK
HEAT/INITIATION. SHEAR IS WEAK HOWEVER A NARROW BAND WITH CAPE
VALUES OF 500 TO 1000 J/KG SO EXPECT AT LEAST SOME ISOLD THUNDER.
HIGH PRESSURE BRINGS DRY AIR FOR THURSDAY. HIGH QUICKLY MOVES
EAST FOR FRIDAY WITH RETURN SOUTHERLY FLOW TO BRING AN INCREASE
OF MOISTURE. SOME AFTERNOON INSTABILITY DEVELOPS THEN A LL JET
KICKS IN OVERNIGHT. RESULTS IN AT LEAST A SLGHT CHANCE FOR
PRECIP FRIDAY INTO FRIDAY NIGHT. INBETWEEN SYSTEMS FOR THE
WEEKEND WITH SEASONAL AND DRY CONDITIONS EXPECTED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1248 PM CDT MON SEP 7 2015
VERY DIFFICULT AVIATION FORECAST OVER THE NEXT 24 HOURS FOR THE KLBF
AND KVTN TERMINALS. THE FIRST AREA OF CONCERN/DIFFICULTY IS THE
PERSISTENCE OF LOW CLOUDS OVER THE KLBF TERMINAL...WITH CURRENT
THINKING THAT MVFR CONDITIONS WILL CONTINUE THROUGH THE AFTERNOON
HOURS TODAY. THIS CURRENT THINKING IS SUPPORTED BY THE LATEST RUNS
OF THE RAP/NAM/AND HRRR MODELS...WHICH KEEP CEILINGS AT OR BELOW
3000FT THROUGH 02Z. THE NEXT AREA OF CONCERN/DIFFICULTY WILL BE THE
TIMING ON AFTERNOON/LATE EVENING CONVECTION WITHIN THE GENERAL
VICINITY OF THE KLBF AND KVTN TERMINALS. LATEST OPERATIONAL HRRR HAS
A LINE OF STORMS MOVING INTO THE SOUTHEASTERN PANHANDLE OF NEBRASKA
AND SOUTHWESTERN NEBRASKA BY 00Z THIS EVENING...AND THEN MOVING INTO
THE KLBF TERMINAL BETWEEN 02Z AND 05Z. A SECOND AREA OF CONVECTION
IS ALSO ANTICIPATED TO FORM OVER NORTHWESTERN NEBRASKA BETWEEN 21Z
AND 23Z...BEFORE MOVING EAST INTO THE KVTN TERMINAL BETWEEN 01Z AND
04Z. UNCERTAINTY DOES EXIST WITH SPATIAL COVERAGE OF THIS SECOND
AREA OF CONVECTION NEAR KVTN...HOWEVER...CURRENT CLEARING OVER
NORTHWESTERN NEBRASKA WOULD SUPPORT THE DEVELOPMENT OF THUNDERSTORMS
THIS AFTERNOON.
ANOTHER ROUND OF LOW CLOUDS ARE POSSIBLE TONIGHT AGAIN OVER THE KLBF
TERMINAL AFTER THE AREA OF SHOWERS/THUNDERSTORMS MOVES THROUGH
THIS EVENING. CONFIDENCE IS HIGH ENOUGH AT THIS TIME TO BRING
BACK IN MVFR CONDITIONS OVER THE KLBF TERMINAL...WITH EVEN THE
CHANCE FOR SOME DRIZZLE AFTER 09Z...HOWEVER...THIS WILL BE HIGHLY
DEPENDENT ON HOW MUCH MIXING (WHICH WOULD TEND TO SCOUR OUT THE
MOISTURE) OCCURS IN THE ATMOSPHERE ONCE THIS EVENINGS STORMS MOVE
THROUGH.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JWS
SHORT TERM...JWS
LONG TERM...MASEK
AVIATION...MOLDAN
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1236 PM CDT MON SEP 7 2015
.UPDATE...
ISSUED AT 1037 AM CDT MON SEP 7 2015
A COMPLEX SITUATION TODAY WITH POTENTIAL FOR TSTMS TO DEVELOP
OVER THE FCST AREA AS WELL AS MOVE IN FROM THE W.
PLEASE SEE THE 1252Z SPC DAY 1 OUTLOOK FOR AN EXCELLENT OVERVIEW
OF THE SITUATION.
YOU`VE PROBABLY SEEN THE UPGRADE TO A SLGT RISK. WE SAW THIS
POTENTIAL YESTERDAY AND BELIEVE IT IS WARRANTED.
ALL THE INGREDIENTS ARE THERE. OUR GREATEST CONCERN IS FROM HWY 6
DOWN INTO N-CNTRL KS IN VICINITY OF THE WARM FRONT. SHORT-TERM HI-
RES MODELS SUGGEST THE FRONT COULD LIFT BACK N INTO WEBSTER-
NUCKOLLS-THAYER COUNTIES. ANY STORMS THAT FORM ON OR NEAR THIS
FRONT WILL PROBABLY BE SUPERCELLS AND WILL NEED TO BE CLOSELY
MONITORED FOR ALL THREATS.
SKYWARN: BE ALERT FOR ACTIVATION IN THE 20Z-21Z TIME FRAME.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 AM CDT MON SEP 7 2015
MOSTLY CLEAR SKIES ARE BEING OBSERVED ACROSS THE LOCAL AREA THIS
MORNING...ALBEIT SOME LOW LEVEL STRATUS HAS BEGUN TO DEVELOP IN
SPOTS. WHILE THIS STRATUS IS PATCHY AT THE MOMENT...EXPECT THIS
STRATUS TO CONTINUE TO SPREAD IN COVERAGE THROUGH DAY BREAK...WITH
SOME LOCALLY DENSE FOG ALSO POSSIBLE THROUGH THE EARLY MORNING
HOURS. THUS FAR...FOG HAS NOT BEEN ABLE TO DEVELOP...BUT WITH DEW
POINT DEPRESSIONS CONTINUING TO SHRINK AND A FEW TEMPS NOW
REACHING THEIR ASSOCIATED DEWPOINT VALUES...CONTINUE TO THINK THE
LATEST HRRR MIGHT BE CORRECT WITH AT LEAST SOME PATCHY DENSE FOG
DEVELOPING AROUND SUNRISE. AS A RESULT...CONTINUED TO MAINTAIN THE
LOWER VISIBILITY WORDING FOR THE MORNING HOURS OF THE FORECAST AND
WILL ALSO CONTINUE TO ADVERTISE IN THE HWO.
WITH SOME CONVECTION ALREADY FORMING ACROSS THE HIGH PLAINS...AND
FAVORABLE UPPER LEVEL JET DYNAMICS EXPECT BY MID AFTERNOON...
EXPECT SOME SHOWERS AND THUNDERSTORMS TO DEVELOP AND MOVE ACROSS
THE REGION...GENERALLY FAVORING AREAS ACROSS SOUTH CENTRAL
NEBRASKA. MODEL SOUNDINGS ARE INDICATIVE OF AMPLE CAPE ACROSS THE
REGION...AND THIS INSTABILITY COMBINED WITH 0-6KM SHEAR VALUES
UPWARDS OF 50KTS EXPECTED LATER IN THE DAY...WOULD NOT BE
SURPRISED TO SEE A FEW STRONG AND ORGANIZED THUNDERSTORMS DEVELOP
ACROSS THE LOCAL AREA. LATEST CONVECTIVE OUTLOOK FROM SPC IS
INDICATIVE OF THIS...WITH THE ENTIRE AREA RIGHT IN THE MIDDLE OF A
MARGINAL RISK FOR SEVERE WEATHER THIS AFTERNOON. AS WITH YESTERDAY
...WHILE THE OVERALL TORNADO THREAT IS FAIRLY LOW...A 2 PERCENT
TORNADO RISK IS IN THE LATEST OUTLOOK...AND WILL ADD THIS MENTION
TO THE HWO DESPITE LARGE HAIL AND THUNDERSTORM WIND GUSTS BEING
THE PRIMARY CONCERNS.
TEMPERATURE WISE...EXPECT MOST AREAS TO STRUGGLE TO REACH OR
SLIGHTLY EXCEED 80 DEGREES THIS AFTERNOON...WHICH WILL BE A NICE
CHANCE FOR MOST FOLKS. ONCE SKIES CLEAR AND RAINFALL CHANCES
DIMINISH SOME OVERNIGHT...EXPECT A SEASONABLY COOL START TO
TUESDAY FOR THE LOCAL AREA...WITH NEAR TO SLIGHTLY ABOVE SEASONAL
NORMS FOR LOW TEMPERATURES...WITH FORECAST LOWS GENERALLY FALLING
INTO THE UPPER 50S ACROSS OUR NORTH...AND INTO THE LOWER TO MIDDLE
60S ACROSS NORTH CENTRAL KANSAS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 405 AM CDT MON SEP 7 2015
PRIMARY FORECAST CONCERN THROUGH THE LONG TERM LIES WITH
PRECIPITATION CHANCES.
THE START OF THE PERIOD SHOWS MODELS NOT IN TOO BAD OF AGREEMENT
WITH THE OVERALL UPPER LEVEL PATTERN...WITH THE CWA UNDER ZONAL TO
SLIGHTLY SWRLY FLOW...THANKS TO BROAD TROUGHING CONNECTED TO A LOW
PRESSURE SYSTEM LOCATED OVER NORTH CENTRAL CANADA. AT THE SFC...
STILL EXPECTING THERE TO BE A FRONTAL BOUNDARY MEANDERING AROUND
THE AREA...THOUGH EXACT PLACEMENT IS UNCERTAIN AS IT WILL LIKELY
BE AFFECTED BY ANY THUNDERSTORMS MOVING THROUGH TONIGHT. CONTINUE
TO HAVE POPS RIGHT OFF THE BAT TUESDAY MORNING...LINGERING
ACTIVITY FROM TONIGHT...WHICH IS EXPECTED TO BE SLIDING OFF TO THE
EAST WITH A GRADUALLY VEERING/WANING LLJ. THINKING IS THAT THERE
WILL BE AT LEAST A BIT OF A BREAK IN ACTIVITY LATER IN THE MORNING
PERHAPS INTO THE EARLY AFTERNOON HOURS...BUT ANOTHER LOBE OF
SHORTWAVE ENERGY ASSOCIATED WITH THAT UPPER LEVEL CANADIAN LOW IS
EXPECTED TO MOVE INTO THE AREA FROM THE NW LATE IN THE
AFTERNOON...PROVIDING THE OPPORTUNITY FOR ADDITIONAL
THUNDERSTORMS. WHILE KEPT POPS IN PLACE CWA-WIDE DURING THE
AFTERNOON...HAVE 30-40 POPS GOING ACROSS THE SERN PORTIONS OF THE
CWA...CLOSER TO THE MAIN SFC FRONT WHICH LOOKS TO EXTEND FROM EAST
CENTRAL TO SOUTH CENTRAL PORTIONS OF KS BY TUES EVENING. HAVE SOME
LINGERING 20 POPS DURING THE EVENING HOURS...BUT KEPT THE FORECAST
DRY POST-06Z AS THINGS GET PUSHED FURTHER S/SE. CONFIDENCE IN
TEMPS FOR TUESDAY IS NOT HIGH...AND WILL BE GREATLY AFFECTED BY
LINGERING PRECIP/CLOUDS AS WELL AS THE ULTIMATE LOCATION OF THE
SFC BOUNDARY. AT THIS POINT...HIGHS ARE FORECAST TO REACH THE
UPPER 70S TO LOWER 80S.
THE FORECAST FOR WED IS A DRY ONE...WITH THE TUES SYSTEM EXPECTED
TO PUSH OFF TO THE EAST...LEAVING MORE NWRLY /BUT STILL LOW
AMPLITUDE/ UPPER LEVEL FLOW IN ITS WAKE. A WEAK SFC PATTERN AND
LIGHT WINDS TO START THE DAY IS EXPECTED TO GIVE WAY TO MORE
SOUTHERLY WINDS WITH TIME...AS SFC LOW PRESSURE BECOMES BETTER
ORGANIZED TO OUR WEST AHEAD OF THE NEXT UPPER LEVEL SYSTEM
APPROACHING THE REGION FROM THE NW. THE LACK OF A NOTABLE CHANGE
IN AIR MASS BEHIND THE EARLY WEEK FRONT LOOKS TO KEEP HIGH TEMPS
FOR WED IN THE UPPER 70S/LOWER 80S.
LOOKING AT THE WED NIGHT THROUGH EARLY SAT PERIOD...CONFIDENCE IN
THE FORECAST IS NOT HIGH...AS PLENTY OF DIFFERENCES BETWEEN MODELS
REMAIN. THE LATEST RUN OF THE GFS SHOWS THE POSSIBILITY OF A
COUPLE OF SHORTWAVE DISTURBANCES MOVING THROUGH DURING THIS TIME
FRAME...WHILE THE ECMWF SHOWS A MORE ORGANIZED CLOSED LOW
DEVELOPING BY THURS EVENING OVER THE WRN GREAT LAKES AND PUSHING
OFF TO THE EAST. ONE OF THE RESULTING DIFFERENCES IS THE GFS WOULD
BRING A COUPLE OF SHOTS AT PRECIP...VS THE LIKELY JUST ONE SHOT
VIA THE ECMWF. HAD INHERITED A FEW PERIODS OF POPS IN THIS TIME
FRAME...AND WITH THE GFS STILL SUPPORTING THAT WILL KEEP IT
GOING...BUT IF THINGS TREND TOWARD THE 00Z ECMWF...SOME OF THOSE
PERIOD WOULD NEED TO HAVE POPS REMOVED. WE SHALL SEE. BOTH
SOLUTIONS SHOW ANOTHER SFC COLD FRONT MOVING THROUGH THE
REGION...WITH THE ECMWF SHOWING A BETTER PUSH OF COOLER AIR THAN
THE GFS AT THIS POINT. FORECAST HIGHS REMAIN A BLEND THURS-
SAT...DROPPING BACK INTO THE 70S CWA-WIDE.
BETTER AGREEMENT KEEPING SUN DRY...WITH HIGHS REBOUNDING BACK
INTO THE 80S FOR MAINLY THE SWRN THIRD OR SO OF THE CWA.
&&
.AVIATION...(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z TUE AFTERNOON)
ISSUED AT 1236 PM CDT MON SEP 7 2015
SIGNIFICANT WX ISSUES: +TSRA POTENTIAL MAINLY 22Z-03Z THEN LIFR OR
VLIFR STRATUS AND FOG POSSIBLE AGAIN 09Z-15Z TOMORROW.
THIS AFTERNOON: A BAND OF SHWRS WITH EMBEDDED THUNDER HAS EXITED
EAR AND WILL MOVE THRU GRI BEFORE 19Z. LIFR CIGS SHOULD EVENTUALLY
LIFT TO IFR AND EVENTUALLY MVFR. TIMING IS HIGHLY UNCERTAIN. SCT
TSTMS WILL ERUPT AFTER 21Z AND THERE IS POTENTIAL FOR 1" HAIL OR
LARGER AND G50 KTS IF EITHER TERMINAL TAKES A DIRECT HIT. LIGHT
E-NE WINDS UNDER 10 KTS AWAY FROM ANY TSTMS. CONFIDENCE: MEDIUM
TONIGHT: TSTMS END WITH A PERIOD OF MULTI-LAYERED VFR CIGS BEFORE
IFR STRATUS AND POSSIBLY FOG REDEVELOPS AFTER 06Z. LIGHT NE WINDS
UNDER 10 KTS. CONFIDENCE: MEDIUM
TUE THRU 18Z: PROBABLY IFR TO START IN FOG/STRATUS WITH GRADUAL
IMPROVEMENT TO MVFR BY 18Z. CONFIDENCE: MEDIUM
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...ROSSI
LONG TERM...ADP
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
302 PM MDT MON SEP 7 2015
.SYNOPSIS...
STORMS WILL CONTINUE THIS EVENING LARGELY FOR AREAS SOUTH OF
INTERSTATE 40 WHERE SPOTTY LOCATIONS MAY SEE A HALF INCH OR MORE
OF RAIN. A BACK DOOR COLD FRONT WILL SLIDE DOWN THE PLAINS
TUESDAY AND TUESDAY NIGHT BEFORE PUSHING THROUGH THE GAPS OF THE
CENTRAL MOUNTAIN CHAIN WEDNESDAY MORNING. SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE BEHIND THE FRONT ACROSS THE PLAINS.
TEMPERATURES WILL COOL IN THE WAKE OF THE FRONT...BUT WILL STILL
BE RIGHT AROUND NORMAL VALUES FOR EARLY SEPTEMBER WEDNESDAY
AFTERNOON. MID LEVEL DRY AIR WILL CONTINUE TO PUSH INTO THE STATE
ON THURSDAY AND FRIDAY...BUT ANOTHER BACK DOOR FRONT WILL BE
LURKING AS WELL.
&&
.DISCUSSION...
MOST OF THE RATHER WELL-BEHAVED STORMS TODAY HAVE STAYED SOUTH OF
I-40 AS EXPECTED. HRRR SUGGESTS THAT THE ABQ METRO AREA MAY SEE
SOME ACTION SHORTLY AFTER 00Z...BUT MOST OF THE ACTIVITY SHOULD
END BY MIDNIGHT ACROSS ALL AREAS.
STILL LOOKING FOR A BACK DOOR COLD FRONT TO MOVE INTO AT LEAST NE
NM ON TUESDAY BEFORE SLIDING SOUTH AND WEST TUESDAY NIGHT. THE
FRONT CONTINUES TO LOOK STRONGER WITH EACH MODEL RUN...AND A
BREEZY EAST CANYON WIND NOW LOOKS MORE LIKELY EARLY WEDNESDAY
MORNING FOR THE RIO GRANDE VALLEY. THE BIGGEST QUESTION CONTINUES
TO BE HOW MUCH PRECIPITATION WILL ACCOMPANY THE FRONT. GFS
CONTINUES TO BE VERY BULLISH BREAKING OUT STORMS ACROSS MUCH OF
EASTERN NM IN MOIST UPSLOPE FLOW TUESDAY NIGHT. OTHER MODELS ARE
LESS ENTHUSED. IT CERTAINLY SEEMS POSSIBLE SINCE MODELS ARE NOT
SHOWING AS MUCH DRYING AT MID LEVELS AS THEY WERE
YESTERDAY...EXCEPT FOR IN THE FAR NW. GIVING A NOD TO THE GFS
ENSEMBLE MEMBERS...WHICH ARE MUCH LIKE THEIR OPERATIONAL
COUNTERPART... BUMPED UP POPS A BIT MORE ACROSS THE EAST.
MOST MODELS NOW SHOWING CONVECTION ALONG THE CENTRAL MTN CHAIN ON
WEDNESDAY AFTERNOON WITH CONTINUED MOIST UPSLOPE FLOW. STORMS
SHOULD BE MORE ROBUST SOUTH OF I-40 WHERE MID LEVEL DRYING IS NOT
AS PREVALENT. HIGH TEMPERATURES ON WEDNESDAY SHOULD DROP AT LEAST
3 TO 8 DEGREES FROM TUESDAYS READINGS...THOUGH THIS WILL MEAN
TEMPS WILL ACTUALLY BE RIGHT AROUND NORMAL.
THE MID LEVEL DRY AIR NUDGES IN FARTHER ON THURSDAY...AND
CONVECTIVE COVERAGE SHOULD WANE A BIT. AREAS SOUTH OF HWY 60
SHOULD HAVE THE BEST STORM CHANCES. THEREAFTER...CONFIDENCE
REMAINS VERY LOW AS MODELS CONTINUE TO YO-YO THE NEXT BACK DOOR
FRONT AROUND. THE ECMWF IS BACK ON SCHEDULE FOR THE FRONT TO
ARRIVE ON FRIDAY...WHILE THE GFS IS AROUND 12 HOURS LATER AND ALSO
MUCH STRONGER. THIS WILL OBVIOUSLY HAVE SERIOUS IMPLICATION ON
POPS AND TEMPS...SO GENERALLY WENT FOR A MIDDLE OF THE ROAD
FORECAST FOR NOW.
34
&&
.FIRE WEATHER...
HIGH PRESSURE ALOFT IS FORECAST TO BUILD INTO THE GREAT BASIN THIS
WEEK...EVENTUALLY CUTTING OFF THE FLOW OF MOISTURE FROM THE
SOUTH...WHILE SHUNTING HURRICANE LINDA WEST OF BAJA CA/SOCAL. THIS
SHOULD LEAD TO A DRYING TREND FOR WESTERN NEW MEXICO. LOW LEVEL
MOISTURE WILL SLOSH BACK AND FORTH OVER CENTRAL AND EASTERN NEW
MEXICO THIS WEEK...DEPENDING ON TIMING OF 2 BOUNDARIES...ONE
EXPECTED TUESDAY/TUESDAY NIGHT AND A SECOND...WHICH THE GFS IS NOW
PORTRAYING AS STRONGER THAN IT HAS IN SEVERAL RUNS...ON
FRIDAY/FRIDAY NIGHT.
SO FAR THIS AFTERNOON...MOST OF THE CONVECTION HAS BEEN RELEGATED TO
AREAS ALONG AND SOUTH OF INTERSTATE 40...AS THE HRRR SUGGESTED.
WETTING RAIN FOOTPRINTS TO BE FAIRLY SMALL AS CELLS TRACK TO THE
EAST/NORTHEAST...AND ACTIVITY IS INDICATED TO DIMINISH BY MID
EVENING.
TUESDAY/WEDNESDAY ARE TRANSITION DAYS IN WHICH THE UPPER AIR PATTERN
SHIFTS FROM WEST TO NORTHWEST/NORTH WINDS ALOFT...IMPORTING
CONSIDERABLY DRIER AIR AT THE MID LEVELS. THE SURFACE BOUNDARY FOR
TUESDAY/TUESDAY NIGHT APPEARS A BIT MORE VIGOROUS AND MAY PUSH SOME
LOW LEVEL MOISTURE INTO THE RGV...WHICH MIXES OUT TO SOME EXTENT
WEDNESDAY...WHEN BEST CHANCES FOR WETTING RAIN WILL BECOME FOCUSED
ALONG THE CENTRAL MT CHAIN AND SOUTH OF I-40. PRECIPITATION CHANCES
TAPER DOWN THURSDAY INTO FRIDAY...BUT ANOTHER BOUNDARY COULD
REPLENISH LOW LEVEL MOISTURE INTO THE CENTRAL/EAST BY SATURDAY.
TOWARDS THE END OF THIS WEEK...AND INTO NEXT WEEK...FORECAST
VARIABLES CONTINUE TO BE QUITE VARIABLE WITH RUN TO RUN MODEL FLIP
FLOPPING. THE 12Z GFS DEVELOPS A VIGOROUS SHORT WAVE/CLOSED LOW ON
THE EASTERN PERIPHERY OF THE UPPER RIDGE OVER ERN NM/CHIHUAHUA THIS
WEEKEND THEN EJECTS IT NEWD EARLY NEXT WEEK. THE ECMWF HAS OTHER
IDEAS...MAINLY A 590 PLUS HIGH CENTER OVER NM. IN FACT...THE DEEP
UPPER TROF DEPICTED 24 HRS AGO BY BOTH NEAR 240 HRS HAS VANISHED.
KEEPING THE LOW CONFIDENCE IN MIND...HIGH HAINES WILL BE FOUND OVER
PORTIONS OF CENTRAL AND WRN NM MID TO LATE THIS WEEK. POOR OVERNIGHT
RECOVERIES WILL PLAGUE PORTIONS OF THE NW DURING THIS TIME...AND MIN
RH VALUES MAY FALL BELOW 15 PERCENT. HIGHS WILL BE CLOSE TO AVERAGE
FOR THE SEASON THROUGH THE UPCOMING WEEKEND. OVERNIGHT LOWS MAY FALL
TO NEAR FREEZING AT SOME OF THE NRN MT HIGHER TERRAIN OBS SITES MID
TO LATE WEEK. VENT RATES FORECAST TO BE GOOD TO EXCELLENT
TUESDAY...THEN DECREASE WEDNESDAY WITH AREAS OF FAIR TO POOR
FORECAST ALONG AND SOUTH OF I-40. WIDESPREAD FAIR TO POOR RATES
ANTICIPATED FRIDAY CENTRAL AND EAST.
&&
.AVIATION...
18Z TAF CYCLE
IN GENERALLY WLY STEERING FLOW FOR CONVECTION. SHORT TERM MODELS
SUGGEST A DRIER ENVIRONMENT NW AND NORTH CENTRAL NM WITH SCT
SHOWERS AND STORMS ALONG AND SOUTH OF INTERSTATE 40 BEFORE 06Z.
THE STRONGER STORMS WILL PRODUCE BRIEF MODERATE TO HEAVY RAIN WITH
LCL MVFR CIGS/VSBYS AND OCCASIONAL MT OBSCURATIONS AS WELL AS WND
GUSTS TO 40KT. OTHERWISE VFR.
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 56 87 52 87 / 5 0 0 0
DULCE........................... 42 81 40 80 / 5 10 5 10
CUBA............................ 50 79 47 77 / 10 5 5 10
GALLUP.......................... 51 84 45 84 / 20 10 0 0
EL MORRO........................ 49 79 45 79 / 30 20 10 10
GRANTS.......................... 50 82 47 83 / 30 10 5 5
QUEMADO......................... 52 79 50 80 / 30 20 10 20
GLENWOOD........................ 58 86 58 85 / 20 30 20 20
CHAMA........................... 44 77 42 77 / 10 10 10 20
LOS ALAMOS...................... 59 80 55 79 / 20 5 5 10
PECOS........................... 56 79 53 75 / 20 10 10 30
CERRO/QUESTA.................... 51 77 48 75 / 5 10 10 20
RED RIVER....................... 41 70 43 68 / 10 20 20 30
ANGEL FIRE...................... 48 70 45 69 / 10 20 20 20
TAOS............................ 47 80 46 78 / 0 10 5 20
MORA............................ 53 76 49 73 / 20 20 20 20
ESPANOLA........................ 53 85 53 84 / 10 0 0 5
SANTA FE........................ 58 83 56 79 / 10 10 5 20
SANTA FE AIRPORT................ 56 86 55 83 / 10 5 0 10
ALBUQUERQUE FOOTHILLS........... 62 86 61 83 / 20 0 5 20
ALBUQUERQUE HEIGHTS............. 64 88 63 85 / 20 0 0 10
ALBUQUERQUE VALLEY.............. 59 90 62 87 / 20 0 0 10
ALBUQUERQUE WEST MESA........... 60 89 61 85 / 20 0 0 10
LOS LUNAS....................... 59 91 60 88 / 20 0 5 10
RIO RANCHO...................... 62 90 60 87 / 20 0 0 10
SOCORRO......................... 63 88 61 88 / 30 5 10 20
SANDIA PARK/CEDAR CREST......... 57 82 56 79 / 20 5 10 20
TIJERAS......................... 59 85 57 81 / 20 5 10 20
MORIARTY/ESTANCIA............... 51 85 53 81 / 10 5 10 30
CLINES CORNERS.................. 56 82 54 77 / 30 10 10 40
GRAN QUIVIRA.................... 58 83 57 80 / 40 10 10 40
CARRIZOZO....................... 62 88 60 84 / 40 20 20 40
RUIDOSO......................... 58 79 57 75 / 40 30 20 50
CAPULIN......................... 54 79 53 77 / 10 20 20 10
RATON........................... 52 85 51 82 / 10 20 20 10
SPRINGER........................ 53 85 53 81 / 10 20 20 10
LAS VEGAS....................... 53 81 51 77 / 20 20 20 30
CLAYTON......................... 63 85 59 82 / 10 20 20 10
ROY............................. 59 83 56 79 / 10 20 20 10
CONCHAS......................... 66 91 63 87 / 20 10 20 10
SANTA ROSA...................... 65 90 62 85 / 20 10 20 30
TUCUMCARI....................... 66 93 63 87 / 30 20 20 10
CLOVIS.......................... 64 91 63 84 / 30 20 30 20
PORTALES........................ 65 90 63 83 / 30 20 30 30
FORT SUMNER..................... 66 91 64 84 / 30 10 20 20
ROSWELL......................... 68 94 67 88 / 30 10 20 30
PICACHO......................... 62 90 62 83 / 40 20 20 40
ELK............................. 61 81 60 77 / 40 20 20 40
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
34
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
254 PM EDT MON SEP 7 2015
.SYNOPSIS...
A LATE SUMMERTIME PATTERN OF WARM DAYS WITH SCATTERED AFTERNOON
AND EVENING THUNDERSTORMS WILL CONTINUE FOR THE NEXT FEW DAYS. THE
NEXT SIGNIFICANT WEATHER SYSTEM TO AFFECT THE AREA WILL BE A COLD
FRONT THAT MOVES SLOWLY TOWARD THE AREA THIS WEEKEND AND MAY SLIP
OFFSHORE EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM MONDAY...PRECIPITABLE WATER TRENDING UPWARD INLAND PER
LATEST SATELLITE-DERIVED BLENDED PWAT SCANS...HAVING NEARLY ERASED
THE DRY COLUMN FOOTHOLD OVER INTERIOR NE SC AND SE NC. PRESENTLY
LAND CONVECTION HAS SPROUTED AND UNDERWAY...ASSISTED BY A MYRIAD OF
UPDRAFT STARTERS INCLUDING OUTFLOW BOUNDARIES...DIFFERENTIAL HEATING
AND LOW-LEVEL CONVERGENCE ALONG A WEAK SEA BREEZE BOUNDARY. RECENT
KLTX VWP DATA SHOWS EAST WINDS IN THE LOWEST 8KFT WITH SE-S FLOW
THROUGH THE MIDDLE AND UPPER LEVELS. IT IS EXPECTED THAT DIURNAL
COOLING THROUGH EVENING WILL REMOVE SOME OF THE STEAM FROM CELLS AND
A DECREASE IN AREAL COVERAGE INLAND. A TRANSITION TO INCREASED
MARINE CONVECTION TONIGHT AS BUOYANCY INCREASES OVER THE WATERS
ESPECIALLY INTO VERY EARLY TUESDAY. AS A RESULT MENTIONABLE POPS ARE
RETAINED ALONG AND NEAR THE COAST OVERNIGHT. 70-75 MOST LOCATIONS
FOR MINIMUM TEMPERATURES TUESDAY DAYBREAK 76-79 BEACHES. PATCHES OF
MIST AND FOG CANNOT BE RULED OUT INLAND UNDER PARTIALLY CLEAR SKIES
INTO VERY EARLY TUESDAY.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 PM MONDAY...LOW PRESSURE WILL CONTINUE TO RETROGRADE AS RIDGING
BUILDS IN FROM THE SOUTHEAST AT LEAST THROUGH EARLY WEDNESDAY. AFTER
THIS A SHORTWAVE TROUGH MOVES INTO THE TENNESSEE VALLEY WHICH LOWERS
HEIGHTS ONCE AGAIN. AT THE SURFACE A WEAK SOUTHEAST FLOW WILL BE IN
PLACE TUESDAY. A BETTER DEFINED PIEDMONT TROUGH WILL DEVELOP
WEDNESDAY AFTERNOON. POPS WILL BE MORE RELEGATED TO A SUMMERTIME
PATTERN WITH THE LOSS OF THE UPPER LEVEL LOW INFLUENCES. SLIGHT TO
LOW CHANCE POPS ARE IN PLACE THROUGHOUT THE PERIOD WITH THE HIGHEST
VALUES MOSTLY IN THE AFTERNOONS AND EVENINGS. CONTINUED TO LEAN MORE
IN THE DIRECTION OF THE GFS/MAV NUMBERS WHICH ARE VERIFYING MUCH
BETTER WITH MORNING LOWS VS THE OTHERS.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 300 PM MONDAY...INLAND SURFACE TROUGHINESS BECOMES ESTABLISHED
ON THURSDAY AND A SOUTHWESTERLY RESULTANT SEABREEZE EXPECTED.
LOOKING FOR A SLIGHTLY WARM AFTERNOON WITH POSSIBLY DECENT COVERAGE
OF CONVECTION. COLD FRONT MOVES IN ON FRIDAY AND LIKELY
DECELERATING. RAIN CHANCES WILL TEND TO INCREASE WITH THE APPROACH
OF THIS BOUNDARY AND FUTURE FORECAST ITERATIONS MAY BE ABLE TO FINE
TUNE WHICH AREAS IF ANY DESERVE HIGHER POPS, HINGING MOST ON THE
SPEED OF THE FRONT. THE WEEKEND IS REALLY SHAPING UP TO BE UNSETTLED
WITH ANOTHER FRONT MOVING INTO THE SOUTHEASTERN U.S. THIS SECONDARY
BOUNDARY WILL BE BEING DRIVING BY AN IMPRESSIVE SYSTEM ALOFT THAT
MAY NOT ONLY YIELD HIGHER RAIN CHANCES BUT PERHAPS SOME STRONGER
THUNDERSTORMS.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
AS OF 18Z...BIT OF A TRICKY AFTERNOON WITH REGARDS TO CONVECTION.
THE HRRR IS NOT VERY ENTHUSED...WITH MAINLY ISOLATED ACTIVITY THROUGH
THE AFTERNOON. GIVEN THAT WE ARE AROUND OUR CONVECTIVE TEMP...AND
THE FACT THAT THE NAM HAS HIGH POPS...WILL KEEP CONVECTION FAIRLY
PREVALENT ALONG THE COAST...PRESSING INLAND AS THE AFTERNOON WEARS
ON. NOT SURE IF THE SHOWERS WILL MAKE IT TO THE INLAND TERMINALS
SO WILL STICK WITH VCSH. THE NAM IS THE MOST AGGRESSIVE...KEEPING
HIGH POPS ALL THE WAY TO 06Z. THINK THIS IS OVERDONE AND WILL
DISSIPATE MOST OF THE CONVECTION BY 02-03Z. STRATUS WILL BE REINTRODUCED
AFTER MIDNIGHT THROUGH MOST OF THE MORNING HOURS. LOOK FOR THE WINDS
TO SHIFT TO SOUTHERLY AS HIGH PRESSURE MOVES OFFSHORE TUESDAY.
EXTENDED OUTLOOK...PREDOMINANTLY VFR WITH BRIEF MVFR AND POSSIBLY
IFR...IN MORNING FOG...AND ISOLATED/SCATTERED AFTERNOON EARLY
EVENING SHOWERS AND THUNDERSTORMS THROUGH THE EXTENDED.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM MONDAY...WINDS TO VEER TO SE-S AND EASE OVERNIGHT AS HIGH
PRESSURE ALONG THE NC/VA INLAND BORDER WEAKENS CONSIDERABLY AND THE
SYNOPTIC FLOW BECOMES CONTROLLED BY LARGER BERMUDA HIGH PRESSURE
FARTHER OFFSHORE. WINDSPEEDS 10 KT OR LESS AFTER MIDNIGHT TONIGHT
INTO EARLY TUESDAY SE-S. MARINERS SHOULD CONSIDER OBTAINING A RADAR
UPDATE BEFORE VENTURING OUT AS SEVERAL STRONG TSTMS MAY BE CRUISING
THE WATERS...MOVING SLOWLY TO THE NW-N TONIGHT AND EARLY TUESDAY.
OUTSIDE OF TSTMS SEAS WILL SETTLE TO 2-3 TONIGHT COMPRISED OF ESE
WAVES 1-2 FT EVERY 9 AND 12 SECONDS...AND A LIGHT SE CHOP.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 PM MONDAY...SOUTHEAST WINDS AROUND TEN KNOTS SHOULD COVER
THE WATERS FOR TUESDAY INTO EARLY WEDNESDAY. A MORE PRONOUNCED
PIEDMONT TROUGH WILL INCREASE WIND SPEEDS SLIGHTLY FOR WEDNESDAY
INTO A 10-15 KNOT RANGE. WINDS VEER TO THE SOUTHWEST LATE AS A FRONT
IN THE TENNESSEE VALLEY EDGES CLOSER. SIGNIFICANT SEAS WILL BE A MIX
OF WEAK WIND WAVES AND A VERY MODEST SWELL COMPONANT TEAMING UP TO
BRING 1-3 FOOTERS. A FEW FOUR FOOTERS COULD ENTER THE MIX LATE.
LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 300 PM MONDAY...A DEVELOPING PIEDMONT TROUGH WILL BRING AN
INCREASED SOUTHWESTERLY FLOW ON THURSDAY AND THE INTRODUCTION OF
SOME 4 FT SEAS ALONG THE OUTER PORTIONS OF THE FORECAST ZONES. THE
APPROACH OF A COLD FRONT FROM THE NORTHWEST WILL EASE THE GRADIENT
EVEN SO SLIGHTLY PERHAPS EASING THE 4 FT SEAS OUT OF THE FORECAST.
THIS BOUNDARY STALLS SOMEWHERE JUST TO OUR WEST WHICH WILL FURTHER
ABATE THE GRADIENT IN ADDITION TO VEERING THE FLOW DIRECTION. HOW
MUCH OF THE LATTER OCCURS WILL DEPEND ON WHERE THE BOUNDARY DECIDES
TO STALL WHICH IS NOT YET CLEAR.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SHK
NEAR TERM...MJC
SHORT TERM...SHK
LONG TERM...MBB
AVIATION...MJC/DL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
128 PM EDT MON SEP 7 2015
.SYNOPSIS...
LOW PRESSURE ALOFT MOVING ACROSS THE GULF COAST STATES WILL
PRODUCE ONSHORE WINDS AND SHOWERS ACROSS THE EASTERN CAROLINAS
TODAY. LATE SUMMER CONDITIONS WILL RETURN MID-WEEK AHEAD OF A
COLD FRONT APPROACHING FROM THE NORTHWEST. THE FRONT MAY STALL
ALONG THE COAST NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 128 PM MONDAY...NO REMARKABLE CHANGES TO THE ONGOING
FORECAST. PARTIAL SUNSHINE WILL AID IN BOOSTING LOW-LEVEL
CONVECTIVE ENERGY...AND A TRANSITION TO DEVELOPING SHOWERS AND
ISOLATED TSTMS OVER LAND SHOULD PREVAIL THROUGH AFTERNOON. IT
WILL BE INTERESTING TO SEE HOW THE 3 DEGREES CELSIUS OF WARMING
AT 500 MB COMPARED TO YESTERDAY...DUE TO THE RETROGRADING COOL
POOL...WILL IMPACT CONVECTIVE BEHAVIOR TODAY. PWAT VALUES OF
1.7-2.0 INCHES WILL BE AMPLE TO RESULT IN POCKETS OF HEAVY RAIN.
OUTSIDE OF CELL-TRAINING...STORM MOTION AROUND 15 KT SHOULD LIMIT
LOCALIZED FLOODING POTENTIAL. THE PREVIOUS DISCUSSION FOLLOWS.
RETROGRESSION OF AN UPPER LOW EVIDENT IN VAPOR MOVIES ACROSS
ALABAMA HAS ALTERED THE UPPER WINDS LOCALLY. KLTX VAD WIND PROFILE
REGISTERING EAST WIND 15-25 KT FROM 1-9KFT WHILE ABOVE THIS SE
15-20 KT FLOW. THIS WILL PUSH SHALLOWER CONVECTION MORE DIRECTLY
EAST WHILE DEEPER TOWERS TRAVEL MORE TO THE NORTHWEST. WEAKENING
UPPER PORTIONS OF THE CUMULO-NIMBUS THROUGH ITS LIFE CYCLE WILL BE
SPREAD NW OF THE PRIMARY RAIN CORES...ALLOWING LIGHTER STRATIFORM
TYPE PCPN/-RA TO REACH AREAS FARTHER INLAND. RECENT AMSU AND SSM/I
PWAT LOOPS SHOW THE PRECIPITABLE WATER GRADIENT HAS FILLED IN AND
MOISTENED AREAS ALONG AND WEST OF I-95 IN ROUGHLY 43MM/1.7 INCH
VALUES...MORE THAN SUFFICIENT VAPOR FOR CONVECTIVE LONGEVITY
INLAND. FORMATION OF CONVECTION IS A GOOD BET THIS AFTERNOON AS
WELL...AS LAND HEATING RAMPS UP. OUTFLOWS AND DIFFERENTIAL HEATING
MECHANISMS WILL BOTH SUPPORT CONVECTIVE INITIATION...AND FORECAST
MAXIMUM TEMPERATURES WILL ADD A ZONE OF WEAK LOW-LEVEL CONVERGENCE
TO THE MIX ALONG THE COASTAL INTERIOR SEA BREEZE FRONT. DIURNAL
COOLING LATE IN THE DAY WILL REMOVE CONVECTIVE INTENSITY AND POP
VALUES WILL SHOW A DECLINE THROUGH EVENING...BUT AN UPTREND IN
MARINE CONVECTION INTO VERY EARLY TUESDAY POSSIBLY DELIVERING
COASTAL SHOWERS.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 AM MONDAY...UPPER TROUGH WILL CONTINUE TO RETROGRADE
WESTWARD ACROSS THE GULF COAST STATES TUESDAY...BUT IN A MUCH WEAKER
FASHION THAN EARLIER IN THE WEEK. AT THE SAME TIME...RIDGING
BLOSSOMING EAST OF FLORIDA WILL EXPAND NORTH INTO THE CAROLINAS
TUESDAY AND WEDNESDAY...WHICH WILL LEAD TO LESS UNSETTLED WEATHER
ALONG WITH WARMER TEMPERATURES BY MID WEEK. TUESDAY WILL BE THE
TRANSITION DAY AND WILL FEATURE A GOOD CHANCE FOR SHOWERS/TSTMS AS
THE SURFACE TROUGH SLOWLY ERODES AND LIFTS NORTH...BUT STILL SERVES
AS A FOCUS FOR CONVECTION IN AN UNSTABLE ENVIRONMENT WITH PWATS JUST
BELOW 2 INCHES. THIS BOUNDARY WILL NOT BE PRESENT ON WEDNESDAY...AND
INCREASING HEIGHTS ALOFT WILL INHIBIT STRONG LIFT...BUT A CONTINUED
VERY MOIST ENVIRONMENT AND ABOVE NORMAL TEMPERATURES WILL ALLOW FOR
MORE TYPICAL DIURNAL CONVECTION ALONG THE SEA BREEZE AND PIEDMONT
TROUGH. TEMPS THROUGH MID-WEEK WILL WARM EACH DAY...FROM NEAR
SEASONABLE TUESDAY...MID 80S FOR HIGHS AND AROUND 70 FOR
LOWS...TO UPPER 80S WEDNESDAY WITH MINS WED NIGHT IN THE LOW TO
MID 70S.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 300 AM MONDAY....LATE SUMMER HEAT TO RETURN FOR THE END OF THE
WEEK AS RIDGING EXPANDS ACROSS THE WESTERN ATLANTIC AND THE EAST
COAST...BUT A COLD FRONT WILL APPROACH LATE FRIDAY AND THEN LIKELY
STALL ACROSS THE REGION DURING THE UPCOMING WKND. WHILE THE AIR MASS
BEHIND THIS FEATURE IS ONLY SUBTLY DIFFERENT FROM THAT OUT AHEAD OF
IT...INCREASING CLOUDS AND CONVECTION WILL BRING A RETURN TO COOLER
TEMPERATURES WITH MORE UNSETTLED CONDITIONS SATURDAY AND SUNDAY.
TEMPS THU/FRI WILL FEATURE A LOT OF READING NEAR 90 DEGREES WITH
TYPICAL SUMMERTIME CONVECTION ACTIVITY EXPECTED. AS THE FRONT
CROSSES AND STALLS THIS WKND...TEMPS WILL COOL TO BELOW CLIMO BUT
CONVECTIVE ACTIVITY WILL RAMP UP WITH A GOOD CHANCE FOR SHOWERS AND
TSTMS SATURDAY AND SUNDAY.
&&
.AVIATION /18Z MONDAY THROUGH FRIDAY/...
AS OF 18Z...BIT OF A TRICKY AFTERNOON WITH REGARDS TO CONVECTION.
THE HRRR IS NOT VERY ENTHUSED...WITH MAINLY ISOLATED ACTIVITY THROUGH
THE AFTERNOON. GIVEN THAT WE ARE AROUND OUR CONVECTIVE TEMP...AND
THE FACT THAT THE NAM HAS HIGH POPS...WILL KEEP CONVECTION FAIRLY
PREVALENT ALONG THE COAST...PRESSING INLAND AS THE AFTERNOON WEARS
ON. NOT SURE IF THE SHOWERS WILL MAKE IT TO THE INLAND TERMINALS
SO WILL STICK WITH VCSH. THE NAM IS THE MOST AGGRESSIVE...KEEPING
HIGH POPS ALL THE WAY TO 06Z. THINK THIS IS OVERDONE AND WILL
DISSIPATE MOST OF THE CONVECTION BY 02-03Z. STRATUS WILL BE REINTRODUCED
AFTER MIDNIGHT THROUGH MOST OF THE MORNING HOURS. LOOK FOR THE WINDS
TO SHIFT TO SOUTHERLY AS HIGH PRESSURE MOVES OFFSHORE TUESDAY.
EXTENDED OUTLOOK...PREDOMINANTLY VFR WITH BRIEF MVFR AND POSSIBLY
IFR...IN MORNING FOG...AND ISOLATED/SCATTERED AFTERNOON EARLY
EVENING SHOWERS AND THUNDERSTORMS THROUGH THE EXTENDED.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 128 PM MONDAY...STEADY EAST-NORTHEAST WINDS EXPECTED ACROSS
THE CAROLINA COASTAL WATERS. VEERING WIND DIRECTIONS AND EASING
WIND SPEEDS TONIGHT. LOOK FOR SHOWERS AND STORMS MOVING ACROSS THE
COASTAL WATERS AND BEACHES MAINLY THIS MORNING...WITH SHOWERS
EXPECTED TO DIMINISH IN COVERAGE THIS AFTERNOON. ADDITIONAL
SCATTERED SHOWERS AND STORMS ARE POSSIBLE OVERNIGHT. SEAS
CURRENTLY 2-4 FEET SHOULD DIMINISH TO AROUND 2 FEET LATE TONIGHT.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 AM MONDAY...BROAD HIGH PRESSURE OFF THE SOUTHEAST COAST
WILL CREATE MORE TYPICAL LATE SUMMER CONDITIONS THROUGH MID-
WEEK...WITH RETURN FLOW DRIVING STRENGTHENING S/SW WINDS THROUGH THE
PERIOD. WINDS THE FIRST HALF OF TUESDAY WILL BE LIGHT AND VARIABLE
AS THE PRESSURE PATTERN REMAINS DIFFUSE...BUT AS THE HIGH PRESSURE
OFFSHORE BECOMES MORE SIGNIFICANT...A S/SW DIRECTION WILL BECOME
PREDOMINANT...AND WIND SPEEDS BY WEDNESDAY WILL RISE TO AROUND 15
KTS. WAVE HEIGHTS TUESDAY WILL BE 1-2 FT AS THE VERY LIGHT WINDS
GAIN LITTLE PURCHASE ON SEAS AND SWELL REMAINS INSIGNIFICANT. WAVE
HEIGHTS WILL BUILD TO 2-3 FT WITH ISOLATED 4 FTERS POSSIBLE
WEDNESDAY ON THE INCREASING WINDS AND A GROWING SE GROUND SWELL.
LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 300 AM MONDAY...HIGH PRESSURE OFFSHORE AND A COLD FRONT
APPROACHING FROM THE NW WILL SANDWICH THE COASTAL WATERS THIS
PERIOD. THE COLD FRONT WILL BE ON THE DOORSTEP OF THE LOCAL WATERS
LATE FRIDAY...BUT ANY WIND SHIFT WILL HOLD OFF UNTIL BEYOND THE
EXTENDED. THIS LEAVES SW WINDS THROUGH THE PERIOD...BUT WITH SPEEDS
INCREASING TO 15-20 KTS AS THE GRADIENT TIGHTENS. AN E/SE 9-10 SEC
SWELL WILL EXIST IN THE WAVE SPECTRUM EACH DAY...BUT WILL BECOME
INCREASINGLY SHADOWED BY AN AMPLIFYING 5-SEC SW WIND WAVE.
SIGNIFICANT SEAS WILL BUILD THROUGH THE PERIOD...FROM 2-3 FT EARLY
THURSDAY TO 3-4 FT ON FRIDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...MJC
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...DL/8
AREA FORECAST DISCUSSION
NWS BISMARCK ND
256 PM CDT MON SEP 7 2015
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 256 PM CDT MON SEP 7 2015
RAIN SHOWERS ENDING BY EARLY THIS EVENING CENTRAL HIGHLIGHT THE
SHORT TERM FORECAST.
WILL CONTINUE TO RELY ON A TIME LAGGED ENSEMBLE OF THE HRRR FOR
POPS THE REMAINDER OF THE AFTERNOON...NAMELY ITS 16-18 UTC
ITERATIONS...WHICH HAS DONE WELL THROUGHOUT THE DAY. DID MAINTAIN
A SLIGHT CHANCE OF THUNDER WITH A FEW...SPORADIC LIGHTNING
STRIKES OBSERVED. EXPECT PRECIPITATION CHANCES...FOCUSED PRIMARILY
ACROSS NORTH CENTRAL NORTH DAKOTA AND THE UPPER JAMES RIVER VALLEY
THE REST OF THE DAY...TO RAPIDLY DECREASE BY 22-23 UTC AS FORCING
FROM TWO SHORTWAVES SOUTH OF THE UPPER LOW NEAR LAKE WINNIPEG
SHIFTS EAST.
FOR TUESDAY...A QUIET...DRY...ALBEIT SLIGHTLY BELOW NORMAL
TEMPERATURE-WISE DAY IS FORECAST SOUTH OF THE NOW FILLING
AFOREMENTIONED LOW. GIVEN GOOD AGREEMENT...UTILIZED A BLEND OF THE
12 UTC GUIDANCE SUITES FOR ALL FIELDS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 256 PM CDT MON SEP 7 2015
NORTHWEST FLOW ALOFT THROUGH FRIDAY WITH FLOW ROTATING AROUND THE
HUDSON BAY LOW AND RIDGE OVER THE EASTERN PACIFIC AND WEST COAST.
SHORTWAVE ENERGY MOVING THROUGH THIS FLOW APPROACHES NORTHERN NORTH
DAKOTA LATE TUESDAY NIGHT/WEDNESDAY MORNING...WITH AN ATTENDANT WEAK
SURFACE LOW AND COLD FRONT. MORE SHORTWAVE ENERGY IMPULSES MOVE
SOUTHEAST ACROSS THE STATE WEDNESDAY AFTERNOON WITH A COLD FRONT
MOVING SOUTH ACROSS THE STATE. THIS WILL RESULT IN SLIGHT CHANCES OF
SHOWERS...MAINLY NORTHWEST AND CENTRAL...ON WEDNESDAY. SEASONABLE
TEMPERATURES WEDNESDAY WITH HIGHS FROM THE UPPER 60S NORTH TO UPPER
70S SOUTH.
ANOTHER SERIES OF SHORTWAVES MOVES ACROSS THE STATE WEDNESDAY NIGHT
WITH A SECONDARY PUSH OF COLD AIR IN THE FORM OF A BACKDOOR COLD
FRONT MOVING SOUTHWEST ACROSS THE STATE. SLIGHT CHANCES OF SHOWERS
WILL REMAIN IN THE FORECAST NORTHWEST AND CENTRAL WEDNESDAY
NIGHT...WITH MAINLY DRY BUT COOL CONDITIONS EXPECTED THURSDAY. LOOK
FOR HIGHS IN THE 60S TO LOWER 70S.
THE UPPER LEVEL WESTERN RIDGE BUILDS BACK INTO THE REGION FOR THE
WEEKEND...WITH DRY CONDITIONS AND SLIGHTLY ABOVE AVERAGE
TEMPERATURES. HIGHS IN THE 70S TO LOWER 80S.
THE MODELS BRING AN UPPER LEVEL SHORTWAVE MOVING THROUGH THE
FLOW...FLATTENING THE RIDGE...BRINGING A CHANCE OF SHOWERS AND
COOLER WEATHER FOR MONDAY WITH HIGHS MAINLY IN THE 60S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 256 PM CDT MON SEP 7 2015
VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD. MID LEVEL
CLOUD COVER WILL REMAIN ACROSS MUCH OF CENTRAL AND EASTERN NORTH
DAKOTA THROUGH THE AFTERNOON. LIGHT SHOWERS EXPECTED TO IMPACT KJMS
THROUGH THE AFTERNOON...AND POSSIBLY KMOT BRIEFLY. PATCHY FOG MAY
BE POSSIBLE AT KBIS/KJMS TONIGHT. HOWEVER...GIVEN HIGH
UNCERTAINTY...LEFT IT OUT OF THE TAFS FOR NOW.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...AYD
LONG TERM...JV
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1238 PM CDT MON SEP 7 2015
.UPDATE...
ISSUED AT 1238 PM CDT MON SEP 7 2015
TRICKY TEMP FORECAST AS CLOUDS AND PRECIP MOVING INTO THE
SOUTHWESETERN COUNTIES HAVE KEPT TEMPS COOLER BUT THE NORTHWEST
HAS QUICKLY GONE UP INTO THE 70S. ADJUSTED ACCORDINGLY...LOWERING
HIGHS A FEW DEGREES IN THE SOUTHWEST AND BUMPING THEM UP IN THE
NORTHWEST. WEB CAMS SHOW THE RADAR RETURNS MOVING IN ARE TAKING A
WHILE TO REACH THE GROUND...BUT WESTERN RANSOM AND SARGENT
COUNTIES ARE FINALLY GETTING SOME RAIN. SCATTERED RAIN SHOWERS
WILL CONTINUE TO BE A THREAT THROUGH THIS AFTERNOON...SO BUMPED UP
POPS A BIT.
UPDATE ISSUED AT 934 AM CDT MON SEP 7 2015
TWEAKED POPS TO INCLUDE THE SHOWERS MOVING INTO THE VALLEY CITY
AREA. NOT MUCH IS REACHING THE GROUND...BUT RETURNS ARE STRONG
ENOUGH AS A SHORTWAVE MOVES UP FROM SOUTH DAKOTA TO INCLUDE A
SMALL CHANCE FOR RAIN THROUGHOUT THIS AFTERNOON. OVERALL KEPT THE
TREND OF INCREASING CLOUDS AND HIGHS TOPPING OUT IN THE 60S TO MID
70S.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 348 AM CDT MON SEP 7 2015
THE MAIN CHALLENGE THIS PERIOD WILL BE SHOWER CHANCES AND
TEMPERATURES. THE AIRMASS CHANGE HAS OCCURRED WITH MUCH COOLER
AND DRIER ADVECTING INTO THE REGION. UPPER LOW WILL SLOWLY
PROPAGATE EAST ACROSS CANADA...AND MOST MODEL GUIDANCE SUGGESTS A
WAVE WITHIN THIS FLOW PATTERN WILL LEAD TO SHOWERS THIS AFTERNOON.
GIVEN THE DRY AIRMASS IN PLACE ANY RADAR RETURNS WILL LIKELY
APPEAR WORSE THAN WHAT IS OCCURRING AT THE GROUND...BUT DID
INCLUDE ISOLD SHOWERS AS HRRR INDICATES WEAK BANDING POTENTIAL.
ANTICIPATE SOLAR TODAY...WHICH SHOULD ALLOW MAX TEMPS INTO THE
70S.
DRY ON TUESDAY...AND SLIGHTLY COOLER AS THE UPPER LOW IN CANADA
SHIFTS EAST.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 348 AM CDT MON SEP 7 2015
WEDNESDAY...UPPER WAVE IN NORTHWEST FLOW ALOFT WILL PROVIDE SHOWER
CHANCES...ALTHOUGH MOST 00Z GUIDANCE IS SLOWER AND TIMES THIS
FORCING INTO THE REGION MORE WEDNESDAY NIGHT. THIS WOULD ALLOW
SLIGHTLY WARMER TEMPERATURES DURING THE DAY ON WED. TRENDED THE
FORECAST ACCORDINGLY FOR POPS AND TEMPS.
THURSDAY-SUNDAY...LOW AMPLITUDE LONG WAVE RIDGE/TROUGH OVER
WESTERN CANADA/CENTRAL NORTH AMERICA RESPECTIVELY AMPLIFIES A BIT
BY THE END OF THE PERIOD. THE GFS WAS A FASTER AND A LOWER
AMPLITUDE SOLUTION THAN THE ECMWF. BOTH THE ECMWF AND THE GFS HAVE
BEEN TRENDING SLOWER OVER THE LAST COUPLE MODEL RUNS. TEND TO
PREFER THE ECMWF.
HIGH TEMPS WERE INCREASED ONE TO THREE DEGREES FOR THU AND INCREASED
ONE OR TWO DEGREES FOR FRI AND SAT. HIGH TEMPS WERE DECREASED TWO TO
THREE DEGREES FOR SUN FROM YESTERDAYS FORECAST PACKAGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1238 PM CDT MON SEP 7 2015
A LARGE BATCH OF MID LEVEL CLOUDS WILL MOVE THRU THE AREA THIS
AFTERNOON AND EVENING...AND MAY ALSO DROP A FEW LIGHT SHOWERS.
ECHOES HAVE BEEN DRYING UP AS THEY HAVE MOVED EAST-NE SO AT THIS
POINT WILL ONLY MENTION VCSH AT KFAR/KGFK. OTHERWISE WINDS LOOK TO
REMAIN FAIRLY LOW THROUGHOUT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...TG
LONG TERM...TG/HOPPES
AVIATION...GODON
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1211 PM CDT MON SEP 7 2015
.UPDATE...
ISSUED AT 1205 PM CDT MON SEP 7 2015
INCREASED CLOUD COVER ACROSS MUCH OF CENTRAL NORTH DAKOTA FOR THE
REMAINDER OF THE DAY AHEAD OF TWO SHORTWAVES EMBEDDED IN THE
CYCLONIC FLOW SOUTH OF THE UPPER LOW NORTH OF LAKE WINNIPEG AS OF
17 UTC. AS A RESULT...DID DECREASE HIGHS INTO THE 60S FOR AREAS
TO REMAIN UNDER OVERCAST SKIES. POPS BLENDED TO A TIME LAGGED
ENSEMBLE OF THE 13-15 UTC HRRR ITERATIONS WHICH CONTINUES TO
PERFORM WELL WITH THIS PRECIPITATION EVENT.
UPDATE ISSUED AT 843 AM CDT MON SEP 7 2015
QUICK UPDATE TO BLEND RADAR TRENDS TO THE TIME LAGGED ENSEMBLE OF
THE 10-12 UTC HRRR ITERATIONS...AND ADD AN ISOLATED MENTION OF
THUNDERSTORMS SOUTH CENTRAL THIS MORNING AND THROUGH THE AFTERNOON
WITH A FEW LIGHTNING STRIKES OBSERVED THUS FAR.
UPDATE ISSUED AT 623 AM CDT MON SEP 7 2015
ONLY CHANGE FOR MORNING UPDATE WAS TO TRIM POPS BACK A BIT IN THE
EARLY MORNING AS EXPECT THE ONSET OF SHOWERS WILL BE DELAYED A
LITTLE. OTHERWISE...GOING FORECAST WAS IN GOOD SHAPE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 310 AM CDT MON SEP 7 2015
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL CHANCES FOR
SHOWERS TODAY SOUTHWEST AND CENTRAL...AND COOL/BELOW NORMAL
TEMPERATURES BOTH TODAY AND TUESDAY.
CURRENTLY...UPPER LEVEL LOW PRESSURE SPINNING OVER SOUTHERN
SASKATCHEWAN WITH A 100KT UPPER LEVEL JET ROUNDING THE BASE OF
THE LOW INTO THE WESTERN DAKOTAS. STRONG FLOW ALOFT RESULTING IN
MID LEVEL MOISTURE ADVECTION WITH INCREASING MID AND HIGH LEVEL
CLOUDINESS. DESPITE CLOUDS SOUTHWEST VERY DRY DEWPOINTS IN THE
30S RESULTING IN TEMPERATURES IN THE LOW 40S AND EVEN A FEW UPPER
30S.
THE UPPER JET STREAK IS INDUCING A SUBTLE SURFACE TROUGH OVER
WESTERN SOUTH DAKOTA EARLY THIS MORNING...AND WILL EVENTUALLY
DEVELOP INTO SOUTHWEST AND SOUTH CENTRAL NORTH DAKOTA LATER THIS
MORNING AND AFTERNOON. COUPLED WITH FORCING ALOFT EXPECT SHOWERS
TO DEVELOP NEAR THE TROUGH AXIS AS IT SLOWLY MOVES EAST TODAY.
WHILE WE WILL REALIZE SOME MOISTURE RETURNING BACK INTO THE AREA
INSTABILITY IS VERY MINIMAL SO REMOVED ALL MENTION OF THUNDER FROM
THE FORECAST. FORCING ALOFT MOVES OFF TO OUR EAST AFTER 00Z SO
MAINTAINED A DRY EVENING AND OVERNIGHT PERIOD.
UPPER LOW CONTINUES EAST ACROSS SOUTH CENTRAL CANADA...ROTATING
ANOTHER EMBEDDED WAVE AND ASSOCIATED JET STREAK ACROSS THE STATE
LATE MONDAY NIGHT INTO TUESDAY. AT THIS TIME SFC FORCING LOOKS NIL
WITH SFC HIGH PRESSURE MOVING EAST ACROSS THE REGION SO KEPT THE
TUESDAY MORNING AND AFTERNOON PERIOD DRY FOR NOW.
HIGH TEMPERATURES BOTH TODAY AND TUESDAY VERY COMFORTABLE IN THE
UPPER 60S TO MID 70S. TEMPERATURES TONIGHT SHOULD BE SIMILAR TO
CURRENT CONDITIONS...40S WITH A FEW AREAS DROPPING INTO THE UPPER
30S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 248 AM CDT MON SEP 7 2015
BROAD SHORT WAVE ROTATING AROUND HUDSON BAY LOW PASSES OVER THE
AREA WEDNESDAY AND WEDNESDAY NIGHT...POSSIBLY BRINGING SOME
PRECIPITATION TO OUR AREA. FOR THE REST OF THE WORK
WEEK...NORTHWESTERLY FLOW WITH RIDGING OVER THE WESTERN CONUS WILL
BRING QUIET WEATHER AND COMFORTABLE TEMPERATURES TO THE AREA.
WARMER CONDITIONS RETURN FOR SATURDAY AS RIDGE AXIS PASSES OVER.
BEHIND THE RIDGE...A FEW THUNDERSTORMS MAY DEVELOP INTO SATURDAY
NIGHT. AVERAGE TEMPERATURES RETURN FOR SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1205 PM CDT MON SEP 7 2015
VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD. MID LEVEL
CLOUD COVER WILL REMAIN ACROSS MUCH OF CENTRAL AND EASTERN NORTH
DAKOTA THROUGH THE AFTERNOON. LIGHT SHOWERS EXPECTED TO IMPACTKBIS
AND KJMS THROUGH THE AFTERNOON.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...NH
LONG TERM...JJS
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS NORMAN OK
1218 PM CDT MON SEP 7 2015
.AVIATION...
18Z TAFS... VFR CONDITIONS EXPECTED THIS TAF PERIOD WITH SOME MID
AND HIGH CLOUDS. A FEW SHOWERS/STORMS MAY AFFECT PARTS OF NW OK
TUESDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 614 AM CDT MON SEP 7 2015/
DISCUSSION...
AVIATION DISCUSSION FOR THE 12Z TAFS IS BELOW.
AVIATION...
VFR CONDITIONS ARE EXPECTED TO CONTINUE.
MBS
PREV DISCUSSION... /ISSUED 347 AM CDT MON SEP 7 2015/
DISCUSSION...
HOT WEATHER TODAY AND TUESDAY IS THE FIRST CONCERN...THEN RAIN
CHANCES MAINLY TUESDAY...WEDNESDAY...AND THURSDAY NIGHT AS WELL
AS COOLER WEATHER ARE THE NEXT CONCERNS.
THIS MORNING...LATEST HRRR RUNS HAVE BEEN HINTING THAT A FEW
HIGH BASED SHOWERS AND THUNDERSTORMS MAY FORM OVER NORTHERN
OKLAHOMA...NORTH OF A ELK CITY TO STILLWATER LINE. FOR NOW...DID
NOT MENTION AS NOT SURE THIS WILL OCCUR DUE TO DECENT CAPPING.
THIS AFTERNOON AND EARLY EVENING...A FEW THUNDERSTORMS MAY FORM
SIMILAR TO YESTERDAY IN PARTS OF SOUTHERN OKLAHOMA...MAINLY SOUTH
OF A ARDMORE TO COALGATE LINE AS WELL AS PERHAPS FAR NORTHWESTERN
OKLAHOMA CLOSER TO A FRONT. KEPT 20 PERCENT CHANCES IN THESE
LOCATIONS. ANY STORM WILL MOVE FAIRLY SLOWLY AND BE CAPABLE OF
PRODUCING GUSTY WINDS UP TO 50 MPH AND WELL AS LOCALIZED
DOWNPOURS.
THE HEAT TODAY WILL BE THE MAIN STORY. THINK HIGHS WILL BE VERY
SIMILAR TO YESTERDAY. GENERALLY WENT TOWARDS THE HOTTER SIDE OF
MODEL GUIDANCE. WILL HOLD OFF ON ISSUING A HEAT ADVISORY THOUGH
HEAT INDICES WILL FLIRT WITH THE 105 DEGREE MARK IN MANY
LOCATIONS.
LATE TONIGHT INTO TUESDAY MORNING...A FEW STORMS MAY FORM NEAR
THE APPROACHING COLD FRONT IN NORTHERN OKLAHOMA. KEPT 20 PERCENT
CHANCES TO ACCOUNT FOR THIS. OTHERWISE...RAINFREE AND MUGGY
CONDITIONS WILL PERSIST.
TUESDAY AFTERNOON AND NIGHT...RAIN CHANCES WILL INCREASE ACROSS
THE ENTIRE AREA WITH THE PASSAGE OF A COLD FRONT. STORMS MAY BE
NEAR THE FRONT AND PERHAPS ORGANIZE INTO A LINE. A FEW STORMS MAY
BE STRONG TO PERHAPS SEVERE WITH DAMAGING WINDS UP TO 70 MPH AS
THE MAIN HAZARDS AS DCAPE VALUES WILL EXCEED 1000 J/KG IN A HOT
DEEPLY MIXED ENVIRONMENT. NOT SURE IF STORMS WILL BECOME TOO
WIDESPREAD AND VERY ORGANIZED AS 0-6 KM SHEAR MAY BE MARGINAL.
LOCALLY HEAVY RAINFALL COULD OCCUR AS WELL. HIGHEST RAIN CHANCES
APPEAR TO BE NEAR AND EAST OF I-35.
HIGHS ON TUESDAY MAY SOAR JUST AHEAD OF THE COLD FRONT...THUS WENT
ABOVE MODEL GUIDANCE IN MOST LOCATIONS EXCEPT FAR NORTHERN
OKLAHOMA WHERE MORE CLOUDS AND RAIN MAY KEEP THEM DOWN A BIT.
WEDNESDAY...SOME SHOWERS AND STORMS MAY LINGER OVER SOUTHERN
OKLAHOMA AND WESTERN NORTH TEXAS...MAINLY DURING THE MORNING
HOURS. COOLER TEMPERATURES WILL LIKELY RESULT...THOUGH IT MAY
REMAIN FAIRLY MUGGY.
WEDNESDAY NIGHT THROUGH SUNDAY...COOLER WEATHER IS STILL
FORECAST...THOUGH THERE IS SOME UNCERTAINTY DURING THIS TIME FRAME
WITH THE TIMING OF SYSTEMS AND HOW COOL IT WILL BE. LATEST MODELS
WERE NOT QUITE AS COOL DURING THIS TIME FRAME. THERE SEEMED TO BE
SIGNAL FOR STORMS THURSDAY NIGHT ACROSS MUCH OF THE AREA. RAIN
CHANCES WERE KEPT THURSDAY NIGHT THROUGH SATURDAY NIGHT ACROSS
PARTS OF THE AREA...THOUGH TIMING AND LOCATIONS REMAIN UNCERTAIN.
MBS
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 98 74 96 69 / 10 10 30 60
HOBART OK 103 75 99 69 / 0 10 30 50
WICHITA FALLS TX 99 73 100 72 / 10 0 10 60
GAGE OK 101 76 94 64 / 10 10 40 30
PONCA CITY OK 98 77 91 67 / 10 10 50 70
DURANT OK 97 74 97 72 / 20 20 20 70
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
30/25/25
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
131 PM CDT MON SEP 7 2015
.AVIATION UPDATE...
ISOLATED STORMS AGAIN POSSIBLE THIS AFTERNOON EAST.
ADDITIONALLY...PATCHY MVFR FOG AGAIN EXPECTED TO
DEVELOP OVERNIGHT. VFR CONDITIONS LIKELY OTHERWISE
WITH WIND SPEEDS NEAR OR LESS THAN 6KNTS.
&&
.PREV DISCUSSION... /ISSUED 632 AM CDT MON SEP 7 2015/
UPDATE...
FOR 12Z AVIATION.
DISCUSSION...
LATEST SURFACE OBSERVATIONS SHOWS TEMPERATURES IN THE 60S TO LOW
70S ACROSS THE MID STATE WITH DEWPOINTS ALSO IN THE 60S UNDER
NEARLY CLEAR SKIES. SEVERAL OBS ALSO SHOWING PATCHY FOG ALTHOUGH
NO DENSE FOG HAS BEEN NOTED THUS FAR. WILL KEEP MENTION OF PATCHY
FOG IN THE GRIDS/ZONES THROUGH 14Z. OTHERWISE...ANOTHER HOT AND
HUMID DAY IS ON TAP WITH TEMPERATURES RISING INTO THE 80S PLATEAU
AND LOW 90S ELSEWHERE...SIMILAR TO YESTERDAY. WATER VAPOR IMAGERY
DEPICTS AN UPPER LEVEL LOW CENTERED OVER GEORGIA...WITH DRY AIR ON
THE WEST SIDE OF THE LOW CURRENTLY ACROSS THE MID STATE. 00Z
GFS/ECMWF SLOWLY RETROGRADE THIS LOW TO THE SOUTHWEST OVER THE
NEXT FEW DAYS WHILE MOISTURE ADVECTS WESTWARD AROUND THE NORTH
SIDE OF THE LOW INTO MIDDLE TENNESSEE. THUS EXPECTING ISOLATED
SHOWERS AND STORMS AGAIN TODAY...BUT MAINLY TO THE EAST OF I-65 AS
THE DRY AIR ALOFT LIMITS COVERAGE OVER WESTERN ZONES. THIS
THINKING IS IN LINE WITH THE LATEST HRRR MODEL RUNS WHICH KEEPS
CONVECTION MAINLY OVER THE EASTERN HALF OF THE CWA.
POPS WILL INCREASE WESTWARD ON TUESDAY AS PWATS RISE BACK ABOVE
1.5 INCHES ACROSS MUCH OF THE FORECAST AREA. BY WEDNESDAY...THE
MAIN BELT OF WESTERLIES ACROSS THE NORTHERN CONUS BEGINS TO SINK
SOUTHWARD ACROSS THE TENNESSEE VALLEY...WITH A COLD FRONT PROGGED
TO MOVE ACROSS THE FORECAST AREA ON THURSDAY. THE INCREASE IN
UPPER LEVEL SUPPORT ALONG WITH PWATS RISING TO AROUND 1.75 INCHES
AND THE FRONTAL FOCUS ALL INDICATE FAIRLY WIDESPREAD SHOWERS AND
STORMS WEDNESDAY INTO THURSDAY...WARRANTING CHANCE TO LIKELY POPS
ALONG WITH MUCH COOLER HIGH TEMPS DUE TO PRECIP/CLOUD COVER. 00Z
GFS/ECMWF INDICATE AREA WILL DRY OUT ON FRIDAY...BUT A FEW SHOWERS
ARE POSSIBLE FRIDAY NIGHT AND SATURDAY AS A SECONDARY SURGE OF
COOLER AIR MOVES ACROSS. VERY PLEASANT FALL-LIKE CONDITIONS ARE
ANTICIPATED SATURDAY AND SUNDAY WITH LOW HUMIDITY AND
TEMPERATURES SEVERAL DEGREES BELOW NORMAL FOR THIS TIME OF YEAR.
AVIATION...
12Z TAF DISCUSSION.
MVFR TO LIFR FOG HAS OCCURRED AT KCKV AND KCSV THIS MORNING...AND
COULD CONTINUE UNTIL AROUND 14Z OR SO. OTHERWISE EXPECT VFR
CONDITIONS TO CONTINUE THROUGH THE DAY. FOG MAY AGAIN RETURN
TONIGHT AND INTO THE EARLY MORNING TOMORROW. WINDS WILL BE LIGHT
AND MAINLY OUT OF THE SOUTHEAST TODAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 70 90 72 87 / 0 20 10 40
CLARKSVILLE 68 90 70 87 / 0 10 0 30
CROSSVILLE 66 83 68 80 / 10 20 20 50
COLUMBIA 68 89 70 87 / 0 20 10 40
LAWRENCEBURG 68 86 70 86 / 0 20 20 40
WAVERLY 69 89 70 86 / 0 10 10 30
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1213 PM CDT MON SEP 7 2015
.UPDATE...
UPDATED FOR 18Z AVIATION DISCUSSION...
&&
.PREV DISCUSSION... /ISSUED 1003 AM CDT MON SEP 7 2015/
UPDATE...
ANOTHER HOT AND HUMID DAY IS UPCOMING FOR THE MIDSOUTH.
TEMPERATURES ARE ALREADY IN THE LOW TO MID 80S AS OF 10AM. ONCE
AGAIN THE HRRR IS OVERDOING AFTERNOON THUNDERSTORM COVERAGE.
EXPECT COVERAGE TO BE MINIMAL AT BEST. HIGHS TODAY WILL REACH THE
MID 90S WITH HEAT INDICES NEAR 100. NO CHANGES TO THE PREVIOUS
FORECAST WERE NECESSARY.
PREV DISCUSSION... /ISSUED 317 AM CDT MON SEP 7 2015/
DISCUSSION...
THE MID SOUTH WILL REMAIN POSITIONED BETWEEN UPPER LEVEL HIGH
PRESSURE OVER THE SOUTHERN PLAINS AND AN UPPER LEVEL LOW PRESSURE
SYSTEM OVER GEORGIA TODAY. THIS WILL ALLOW FOR THE CONTINUATION OF
DRY...HOT...AND HUMID CONDITIONS. THE UPPER LOW WILL MOVE
SOUTHWESTWARD THROUGH TUESDAY AND SHOULD SPREAD ISOLATED SHOWERS
AND THUNDERSTORMS INTO PORTIONS OF WEST TENNESSEE NEAR THE
TENNESSEE RIVER AND NORTHEAST MISSISSIPPI BY TUESDAY AFTERNOON.
ELSEWHERE...DRY AND HOT WEATHER WILL CONTINUE ALONG WITH HUMID
CONDITIONS.
THE UPPER LEVEL RIDGE EXTENDING OVER THE AREA EARLY IN THE WEEK
WILL BREAK DOWN BY WEDNESDAY AS A SHORTWAVE TROUGH DIGS ACROSS THE
CENTRAL PLAINS INTO THE LOWER MISSISSIPPI VALLEY. THIS SHOULD
INCREASE CHANCES FOR SHOWERS AND THUNDERSTORMS ACROSS THE AREA AND
KNOCK TEMPERATURES BACK DOWN TO NEAR NORMAL LEVELS FOR THIS TIME
OF YEAR. THE UPPER LEVEL TROUGH SHOULD REMAIN OVER THE REGION
INTO THURSDAY WITH CONTINUED CHANCES FOR SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS.
A STRONGER SHORTWAVE WILL DIVE SOUTHEAST INTO THE REGION ON FRIDAY
AND HELP TO PUSH A COLD FRONT SOUTH ACROSS THE FORECAST AREA.
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL AGAIN BE
POSSIBLE ON FRIDAY AS THE FRONT MOVES THROUGH. SURFACE HIGH
PRESSURE SHOULD BUILD INTO THE AREA AS UPPER LEVEL TROUGHING
REMAINS OVER THE EASTERN HALF OF THE NATION. DRY WEATHER ALONG
WITH COOLER AND LESS HUMID CONDITIONS CAN BE EXPECTED FOR NEXT
WEEKEND.
BY EARLY NEXT WEEK...ATTENTION WILL TURN TO THE WESTERN GULF OF
MEXICO WHERE MODELS ARE HINTING AT POTENTIAL TROPICAL
DEVELOPMENT. LATEST GUIDANCE BRINGS ANY DEVELOPING SYSTEM NORTH
THROUGH THE ARKLATEX AND INTO OUR REGION EARLY NEXT WEEK. PLAN TO
CARRY AN INCREASE IN RAIN CHANCES EARLY NEXT WEEK...BUT WILL NOT
GO AS HIGH AS CURRENT GUIDANCE UNTIL THIS SOLUTION LOOKS MORE
LIKELY. THIS SCENARIO WILL BE WATCHED CLOSELY OVER THE NEXT
SEVERAL DAYS.
JLH
.AVIATION...
12Z TAF CYCLE
VFR CONDITIONS ARE EXPECTED THROUGH THE NEXT 24 HOURS. PATCHY FOG
IS ONCE AGAIN POSSIBLE TONIGHT AT MKL...JBR AND TUP BUT SHOULD
BURN OFF BY 13Z ON TUESDAY.
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1200 PM CDT MON SEP 7 2015
.AVIATION...
/12Z TAFS/
Expect VFR conditions at the terminals the next 24 hours. The
winds will be south at 5 to 10 knots.
&&
.PREV DISCUSSION... /ISSUED 628 AM CDT MON SEP 7 2015/
AVIATION...
/12Z TAFS/
MVFR stratus in the Hill Country was advecting north to the I-10
corridor from Sonora to Junction at 11Z. Will include a tempo for
MVFR ceiling at KSOA and KJCT through 16Z. Otherwise, south to
southeast winds of 10 KTS or less, and VFR conditions are expected
across the rest of the terminals.
PREV DISCUSSION... /ISSUED 356 AM CDT MON SEP 7 2015/
SHORT TERM...
(Today and Tonight)
It will be another persistence forecast today, with the upper
ridge parked over West Central Texas. The HRRR model again
develops isolated afternoon convection, as it has done the last
several days, and will discount the potential. Temperatures should
again rise into the upper 90s with a few areas reaching 100.
04
LONG TERM...
(Tuesday through Sunday)
We looking for one more hot and dry day across west central TX
before the synoptic pattern shifts to one more conducive for
increasing rain chances and more seasonal temperatures. The
subtropical ridge will be building slowly westward on Tuesday as a
strong trough moves across the northern Plains. This trough is
progged to dig over the eastern CONUS, allowing the ridge to build
over the western states. This will result in northwest flow aloft
for our neck of the woods. A weak cold front will move south into
the Lone Star State Tuesday afternoon, likely reaching the south
Plains during the evening hours. Compressional heating ahead of
this cold front will promote afternoon highs in the mid 90s to
near 100 degrees.
Convection is expected to initiate along this cold front as it
approaches Tuesday evening. Some of this activity is expected to
move southeast into the Big Country, maybe as far south as the
Colorado River, Tuesday night into early Wednesday morning. The
cold front is expected to weaken by this time, but convective
outflow should serve as the effective frontal boundary, moving
south into the Concho Valley, and eventually the I-10 corridor,
by Wednesday afternoon. Scattered showers and thunderstorms are
expected to develop, especially along and behind the front. While
rainfall is not expected to be particularly heavy, it should be
fairly widespread with good coverage across the CWA. The increased
cloud cover and precipitation will keep temperatures in check.
Forecast highs for Wednesday afternoon are in the upper 80s to
lower 90s; however, they could be lowered further if rain is
indeed as widespread as anticipated.
The effective cold front will move south over the Edwards Plateau
Wednesday night into Thursday. This will shift the highest rain
chances south of a San Angelo-Brownwood line, favoring the I-10
corridor. In fact, PoPs were removed for areas north of I-20 on
Thursday. This boundary will become more diffuse by the end of the
work-week, but slight chance PoPs were retained over the southern
1/3 of the CWA for Friday. Total rainfall amounts will likely
average less than 1/2 inch, some some areas will see locally
higher amounts, especially over the southeast quadrant of the CWA.
Temperatures are forecast to remain near seasonal norms Thursday
and Friday, generally in the upper 80s to lower 90s. Overnight
lows during this time will be in the mid 60s to near 70 degrees.
PoPs were removed over the weekend as the main upper-level trough
is expected to be to our east by Saturday. Temperatures are
expected to remain near climatology. There remain some differences
in the synoptic pattern, the most notable of which is the tropical
system generated early next week in the western Gulf by the ECMWF.
At the same time, the GFS creates no such system and maintains a
weak cut-off upper-low over the Red River. Will continue to
monitor the model trends at this time, keeping a dry forecast over
the weekend.
Johnson
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 99 76 98 73 / 0 0 5 30
San Angelo 100 75 100 74 / 0 0 0 10
Junction 98 74 97 75 / 0 0 5 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
21
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 249 PM CDT MON SEP 7 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A WEAK COLD
FRONT DROPPING SOUTHEAST FROM THE BAY OF GREEN BAY TO WAUTOMA EARLY
THIS AFTERNOON. AHEAD OF THE FRONT...CLOUDS ARE FAIRLY WIDESPREAD WITH
SCT SHOWERS DEVELOPING OVER THE PAST HOUR OVER THE NORTHERN FOX VALLEY.
LOOK FOR THESE SHOWERS TO CONTINUE TO DEVELOP AHEAD OF THE FRONT OVER
THE NEXT FEW HOURS. BEHIND THE FRONT...MORE BREAKS IN THE CLOUDS EXIST...BUT
THE AIRMASS REMAINS RELATIVELY HUMID UNTIL BEHIND A SECONDARY
FRONT OVER FAR NORTHWEST WISCONSIN AND CENTRAL MINNESOTA. AS A
SHORTWAVE OVER COLORADO MOVES NORTHEAST TONIGHT...SHOWER AND THUNDERSTORMS
CHANCES AS WELL AS POTENTIAL FOR HEAVY RAINFALL ARE THE MAIN FORECAST
CONCERNS.
TONIGHT...THE SURFACE COLD FRONT WILL SAG INTO SOUTHERN WISCONSIN
THIS EVENING. WEAK SHORTWAVE ENERGY EMANATING OUT OF COLORADO WILL
LIFT NORTHEAST TONIGHT AND MOVE INTO THE WESTERN GREAT LAKES AFTER
MIDNIGHT. MID-LEVEL FLOW WILL BACK AHEAD OF THE SHORTWAVE CAUSING
AIR TO RISE OVER THE STALLED BOUNDARY. MODELS HAVE BACKED OFF RAIN
CHANCES WITH THEIR 12Z RUNS HOWEVER...SO WILL FOLLOW SUIT BY KEEPING
ONLY VERY LOW CHANCES OVER THE FAR SOUTHERN CWA THROUGH THE EVENING
AND ONLY RAMP UP PRECIP CHANCES INTO THE LOW LIKELY RANGE OVER EAST-
CENTRAL WI AFTER 09Z. WINDS WILL SHIFT TO THE NORTHEAST BRIEFLY
THIS EVENING WHICH WILL PROMOTE SOME DRIER AIR FILTERING IN TO N-C
WISCONSIN. AS WINDS SHIFT AROUND TO THE SOUTHEAST...MORE OF THE
MOIST/TROPICAL AIR WILL GET RECYCLED WESTWARD...WHICH MAY CREATE FOG
ISSUES IN THIS AREA. HOWEVER...MID AND HIGH CLOUDS WILL BE ARRIVING
BY 06Z...SO WHILE LOWER VSBYS ARE LIKELY...THE PROBABILITY FOR
WIDESPREAD DENSE FOG SEEMS PRETTY LOW. WILL KEEP A PATCHY MENTION
IN THE FORECAST. LOWS RANGING FROM THE MID 50S NORTH TO MID 60S
SOUTH.
TUESDAY...THE SHORTWAVE WILL CONTINUE TO QUICKLY ADVANCE NE INTO
LOWER MICHIGAN BY 18Z BUT A WEAK SURFACE LOW TRAVELLING ALONG THE
STALLED BOUNDARY MAY NOT REACH CENTRAL LAKE MICHIGAN UNTIL 18Z.
WEAK MID-LEVEL FGEN NORTH OF THE LOW IN CONCERT WITH UPPER
DIVERGENCE SHOULD CREATE AN AREA OF RAIN WITH EMBEDDED TSTORMS OVER
CENTRAL AND NORTHEAST WI DURING THE MORNING...WHICH WILL EXIT IN THE
AFTERNOON. PWATS WILL REMAIN NEAR 2.0...SO LOCALLY AMOUNTS OF RAIN
UP TO AN INCH LOOK POSSIBLE...MAINLY OVER EAST-CENTRAL WI. BUT IT
LOOKS LIKE THIS POSSIBILITY WILL BE TO THE EAST OF THE DRENCH AREAS
OF CENTRAL WI. SO DO NOT SEE A NEED FOR A FLASH FLOOD WATCH AT THIS
TIME. CLOUDY WITH HIGHS IN THE LOW TO MID 70S.
.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 249 PM CDT MON SEP 7 2015
DRIER AND COOLER AIR WILL RETURN TO THE REGION WEDNESDAY AND
WEDNESDAY NIGHT AS WEAK SURFACE RIDGING ARRIVES FROM THE PLAINS
STATES. A SHARP UPPER TROUGH DIVING SOUTHEAST FROM CANADA SHOULD
INDUCE A WAVE ALONG A COLD FRONT THAT WILL MOVE ACROSS THE AREA
THURSDAY AND THURSDAY NIGHT. CYCLONIC UPPER FLOW MAY KEEP THE
SHOWERS GOING FRIDAY. DRY...SEASONABLE WEATHER IS EXPECTED
SATURDAY AND SUNDAY AS THE UPPER TROUGH EXITS AND SURFACE HIGH
BUILDS IN.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1204 PM CDT MON SEP 7 2015
A COLD FRONT WILL BE MOVING ACROSS THE AREA THIS
AFTERNOON. ANY SHOWERS OR STORMS ARE EXPECTED TO BE TOO ISOLATED TO
INCLUDE IN THE TAFS. CLEARING SKIES SHOULD MOVE IN FROM NORTHWEST
TO SOUTHEAST THROUGH THE AFTERNOON...THOUGH CLOUDS MAY NEVER DEPART
AT MTW. AHEAD OF A LOW PRESSURE SYSTEM...CIGS/VSBYS ARE EXPECTED TO
FALL AGAIN TONIGHT WITH A CHANCE OF RAIN MOVING IN LATE. BEST
CHANCES OF RAIN WILL OCCUR OVER CENTRAL AND EAST-CENTRAL WI.
WIDESPREAD IFR CONDITIONS ARE LIKELY...POSSIBLY LOWER WITHIN THE
RAIN. SOME MARGINAL IMPROVEMENT IS POSSIBLE BY THE END OF THE TAF
PERIOD.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......RDM
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1135 AM MDT MON SEP 7 2015
.UPDATE...
ISSUED AT 950 AM MDT MON SEP 7 2015
LATEST GUIDANCE SHOWING SOME PRETTY HIGH CAPE OUT OVER THE
SOUTHERN NEBRASKA PANHANDLE ALONG AND SOUTH OF AN ALLIANCE TO
CHEYENNE LINE THIS AFTERNOON. SPC HRRR SIMULATED RADAR SHOWING
QUITE A BIT OF CONVECTION OUT IN THIS AREA THIS AFTERNOON AND
EARLY EVENING. WENT AHEAD AND UPPED POPS FOR THIS AREA THIS
AFTERNOON/EARLY EVENING. UPDATES HAVE BEEN SENT.
AS FOR THE CURRENT RFW...LOOKS TO BE IN PRETTY GOOD SHAPE. POOR
OVERNIGHT RH RECOVERIES FOR 301 AND 302...SO WE ARE STARTING OFF
PRETTY LOW ALREADY THIS MORNING. NAM SOUNDINGS SHOWING 35-40KTS OF
WIND POSSIBLY MIXING DOWN TO THE SURFACE THIS AFTERNOON. WILL KEEP
CURRENT HEADLINES AS THEY ARE.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 415 AM MDT MON SEP 7 2015
PREDAWN WATER VAPOR IMAGERY SHOWED A UPPER LOW SITUATED OVER
CENTRAL SASKATCHEWAN WITH A TROUGH AXIS THROUGH THE NORTHERN
ROCKIES AND GREAT BASIN. UPPER RIDGE EXTENDED FROM NORTHERN MX
TO THE MIDWEST. THE REGIONAL SURFACE ANALYSIS PLACED A COLD
FRONT FROM LAKE SUPERIOR THROUGH CENTRAL IA AND KS THEN NORTH
ALONG THE CO FRONT RANGE AND WEST THROUGH CENTRAL UT. A WEAK
TROUGH WAS LOCATED NEAR THE LARAMIE RANGE. WIDELY SCATTERED
CONVECTION DEVELOPED IN THE VICINITY OF THESE BOUNDARIES...
AIDED BY LIFT FROM RIGHT REAR QUADRANT OF UPPER LEVEL JET.
REGIONAL RADARS DETECTED SHOWERS AND ISOLATED TSTORMS MOVING
NORTHEAST ACROSS WESTERN NE AS WELL AS FROM NORTHWEST CO INTO
SOUTH CENTRAL WY.
THERE IS GOOD AGREEMENT WITH THE 00Z SHORT RANGE MODEL GUIDANCE
PROGGING THE UPPER TROUGH AXIS TO THE WEST TO TRANSLATE EAST
DURING THE NEXT 24 HOURS. THE RIGHT REAR QUADRANT OF THE UPPER
JET WILL REMAIN OVER THE CWA THROUGH TONIGHT. THIS FEATURE ALONG
WITH A COOL FRONT DROPPING SOUTHEAST THROUGH THE PLAINS LATE
TODAY WILL TRIGGER WIDELY SCATTERED AFTERNOON AND EVENING
CONVECTION...MAINLY FROM SOUTHERN LARAMIE RANGE NORTHEAST INTO THE
NE PANHANDLE. TEMPERATURES TODAY WILL BE SIMILAR TO YESTERDAY WITH
HIGHS IN THE 60S AND 70S WEST TO THE 80S EAST. THERE WILL BE A
30-DEGREE WEST TO EAST DEW POINT GRADIENT THIS AFTERNOON. GUSTY
WESTERLY WINDS AND LOW HUMIDITIES WILL INCREASE THE FIRE DANGER
OVER PORTIONS OF EAST AND SOUTH CENTRAL WY THIS AFTERNOON.
TUESDAY WILL BE 5 TO 10 DEGREES COOLER ACROSS THE PLAINS FOLLOWING
THE FRONTAL PASSAGE. THE DRIER AIR MASS WILL SPREAD EAST INTO THE
NE PANHANDLE DURING THE DAY. BREEZY WEST WINDS AND LOW HUMIDITIES
WILL CREATE NEAR-CRITICAL FIRE WEATHER CONDITIONS WEST OF THE
LARAMIE RANGE. THE FLOW ALOFT BECOMES MORE ZONAL WEDNESDAY. IT
WILL BE DRY AND BREEZY DURING THE AFTERNOON ALONG AND WEST OF THE
LARAMIE RANGE. TEMPERATURES WEDNESDAY WILL WARM ABOUT 5 DEGREES.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 330 AM MDT MON SEP 7 2015
WEDNESDAY NIGHT/THURSDAY...FLOW ALOFT REMAINS NORTHWEST. WITH
LIMITED LOW AND MID LEVEL MOISTURE...NOT EXPECTING ANY PRECIPITATION.
FRIDAY...NEAR THE SAME OR SLIGHTLY WARMER THAN THURSDAY BASED ON
THICKNESS AND HEIGHT CHANGES. LOW AND MID LEVEL MOISTURE LOOKS TOO
SCANT FOR ANY PRECIPITATION.
SATURDAY...SLOW WARMING TREND CONTINUES AS RIDGING ALOFT BECOMES
MORE PRONOUNCED OVERHEAD. STILL NOT ENOUGH LOW AND MID LEVEL
MOISTURE FOR SHOWER AND THUNDERSTORM FORMATION.
SUNDAY...FLOW ALOFT BECOMES ZONAL...INDUCING EVEN WARMER TEMPERATURES.
STILL DRY WITH LIMITED CLOUD COVER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH TUESDAY MORNING)
VFR CONDITIONS WILL PREVAIL ACROSS SOUTHEAST WYOMING AND MOST OF
WESTERN NEBRASKA THROUGH TONIGHT. SCATTERED SHOWERS AND ISOLATED
THUNDER WILL DEVELOP NEAR OR JUST EAST OF THE SOUTHERN LARAMIE RANGE
AND MOVE EAST THROUGH THIS EVENING. BRIEF MVFR VIS ARE POSSIBLE
AROUND KCYS AND KSNY BEFORE THE ACTIVITY DISSIPATES BY 03Z. THERE IS
A SLIGHT CHANCE OF LOW CIGS AND PATCHY FOG ACROSS THE WESTERN
NEBRASKA TERMINALS AND KCYS BY EARLY TUESDAY MORNING.
&&
.FIRE WEATHER...
ISSUED AT 310 AM MDT MON SEP 7 2015
CRITICAL FIRE WEATHER CONDITIONS WILL DEVELOP ONCE AGAIN THIS
AFTERNOON FOR PORTIONS OF EAST AND SOUTH CENTRAL WYOMING. WESTERLY
WINDS WILL FREQUENTLY GUST FROM 25 TO 35 MPH WITH MINIMUM RELATIVE
HUMIDITIES DECREASING TO 10 TO 15 PERCENT. THESE CRITICAL CONDITIONS
WILL DEVELOP ACROSS MOST OF ZONE 302...WESTERN PORTIONS OF ZONE
301...AND NORTHERN PORTIONS OF ZONES 303 AND 308. A COOL FRONT
WILL MOVE ACROSS THE PLAINS THIS EVENING...WITH SLIGHTLY COOLER
TEMPERATURES FOR TUESDAY. THERE IS A SLIGHT CHANCE OF AFTERNOON
AND EVENING SHOWERS AND THUNDERSTORMS ALONG AND EAST OF THE
SOUTHERN LARAMIE RANGE. NEAR CRITICAL FIRE WEATHER CONDITIONS ARE
EXPECTED TUESDAY AND WEDNESDAY FOR AREAS ALONG AND WEST OF THE
LARAMIE RANGE.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR WYZ301>303-308.
NE...NONE.
&&
$$
UPDATE...GCC
SHORT TERM...MAJ
LONG TERM...RUBIN
AVIATION...TJT
FIRE WEATHER...MAJ