Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/06/15
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
220 PM MST FRI SEP 4 2015
.UPDATE...UPDATED AVIATION AND FIRE WEATHER DISCUSSIONS.
&&
.SYNOPSIS...
SUFFICIENT MOISTURE WILL REMAIN OVER MUCH OF ARIZONA TODAY PROVIDING
GOOD SHOWER AND THUNDERSTORM CHANCES...PARTICULARLY ACROSS THE
EASTERN HALF OF THE STATE. SOMEWHAT DRIER AIR WILL MOVE INTO THE
REGION OVER THE WEEKEND...REDUCING RAINFALL CHANCES VERY SLIGHTLY.
WHILE SOME THUNDERSTORM CHANCES WILL PERSIST DURING THE FIRST HALF
OF NEXT WEEK...A SUBSTANTIALLY WARMER AND DRIER AIRMASS WILL SPREAD
INTO THE AREA FOR THE LATTER HALF OF THE WEEK.
&&
.DISCUSSION... RELATIVELY STRONG UPPER LEVEL TROF REMAINS SITUATED
ALONG THE PAC NORTHWEST COAST EARLY THIS AFTERNOON PUTTING ARIZONA
UNDER SOUTHWEST FLOW ALOFT. IR IMAGERY AT 1 PM SHOWED TS KEVIN OFF
THE SOUTHWEST TIP OF BAJA CA...AND THE SOUTHWEST FLOW WAS TAPPING
INTO THE MID/HIGH LEVEL MOISTURE BEING SHED OFF OF KEVIN. MUCH OF
THIS MOISTURE HAS OVERSPREAD THE EASTERN HALF OF AZ. MORNING
SOUNDINGS SHOWED A MOIST BUT NOT ESPECIALLY UNSTABLE AIRMASS ACROSS
SOUTH CENTRAL AZ WITH PWAT VALUES NEAR 1.5 INCHES BUT RATHER SKINNY
AND MEAGER CAPE. LOW CAPE VALUES WERE DUE TO THE MODEST LAPSE RATES
AND RATHER MOIST ADIABATIC PROFILES AS SEEN IN THE 12Z RAOBS.
STEERING FLOW THIS AFTERNOON AND EVENING WILL BE SOUTHWESTERLY...AND
THE UPPER STREAMLINES DEPICT A LAMINAR AND SLIGHTLY CONFLUENT
FLOW...NOT CONDUCIVE TO STRONG STORM DEVELOPMENT. DYNAMICALLY
SPEAKING...THERE WILL BE WEAK RIPPLES MOVING IN THE SOUTHWESTERLY
FLOW BUT NO STRONG SHORT WAVES APPEAR READY TO MOVE ACROSS ARIZONA
LATER TODAY. HOWEVER THERE IS A JET STREAK RACING ACROSS CENTRAL
AZ...PUTTING THE CENTRAL DESERTS UNDER THE FAVORABLE RIGHT REAR
QUADRANT LATER THIS AFTERNOON.
AT 1 PM SURFACE DEW POINTS OVER THE CENTRAL DESERTS WERE ELEVATED AND
MOSTLY RANGED FROM THE UPPER 50S TO LOW 60S. WITH MOISTURE ELEVATED
AND INSTABILITY LIMITED...AND DYNAMICS BEING A MIXED BAG...IT IS
TOUGH TO SAY JUST HOW THE CONVECTION WILL PLAY OUT TODAY. SOME
MESOSCALE HI RES MODELS SUCH AS THE HRRR AND WRF4KM SUGGEST WE WILL
SEE STORMS IN THE PHOENIX AREA TONIGHT. AS SUCH WE WILL KEEP ABOUT A
30 PERCENT CHANCE FOR SHOWERS AND THUNDERSTORMS ACROSS SOUTH CENTRAL
ARIZONA LATER THIS AFTERNOON AND OVERNIGHT TONIGHT.
FOR THIS WEEKEND...UPPER TROFFING REMAINS SITUATED ALONG THE WEST
COAST AND ARIZONA WILL STAY UNDER A SOUTHWEST FLOW ALOFT.
HOWEVER...LATEST GUIDANCE DOES NOT REALLY DRY OUT THE EASTERN HALF
OF THE STATE...ESPECIALLY IN THE LOWER LEVELS. PWAT VALUES ARE
FORECAST TO REMAIN NEAR OR ABOVE 1.5 INCHES OVER SOUTH CENTRAL
ARIZONA THROUGH SUNDAY...EVEN THOUGH MUCH OF THE MOISTURE FROM KEVIN
WILL HAVE ALREADY LIFTED OUT TO THE NORTHEAST BY SATURDAY EVENING.
AGAIN...DYNAMICS NOT ESPECIALLY IMPRESSIVE EITHER DAY BUT THERE WILL
LIKELY BE WEAK DISTURBANCES MOVING THROUGH THE SOUTHWEST FLOW FROM
TIME TO TIME...INCREASING THE THREAT FOR SHOWERS OR STORMS.
STREAMLINES REMAIN RATHER LAMINAR AND SOUTHWESTERLY...SIMILAR TO
WHAT IS SEEN TODAY. WE FEEL IT IS A BIT OPTIMISTIC TO REMOVE THE
THREAT FOR CONVECTION FROM THE FORECAST THIS WEEKEND...SO WE WILL
RAISE POPS SLIGHTLY AND KEEP SOUTH CENTRAL AZ UNDER AT LEAST A
SLIGHT CHANCE FOR AFTERNOON/EVENING STORMS BOTH SATURDAY AND SUNDAY.
CONVECTIVE POTENTIAL FOR EARLY NEXT WEEK MAY BE SOMEWHAT MORE MUTED
THAN RECENT DAYS AS DEEP LAYER WINDS VEER SOMEWHAT MORE WESTERLY AS
TROUGHING TRANSLATES INTO THE GREAT BASIN AND NRN ROCKIES.
STILL...BOUNDARY LAYER MOISTURE WILL BE DIFFICULT TO COMPLETELY
SCOUR OUT AND SOME MODEST INFUSION OF MIDLEVEL MOISTURE PEELING OFF
THE REMNANTS OF KEVIN MAY BE POSSIBLE. HOWEVER...THERE REMAINS SOME
DISCONNECT WITH THE MORE QUALITY TROPICAL MOISTURE TO THE
SOUTH...AND THE BEST WV TRANSPORT MAY BE DEFLECTED AROUND THE
FORECAST AREA. IN ADDITION...WITH MID LATITUDE TROUGHING LIFTING TO
THE NORTH AND HEIGHTS ALOFT RISING AHEAD OF THE REMNANT TROPICAL
SYSTEM...MODELS DEPICT SUBSTANTIAL MIDLEVEL WARMING AND INCREASED
CONVECTIVE INHIBITION. KEPT SOME MODEST NEAR CLIMATOLOGY POPS
THROUGH TUESDAY...HOWEVER MEASURABLE RAINFALL AT LOWER DESERT
ELEVATIONS MAY BE DIFFICULT TO COME BY.
SOME MINOR UNCERTAINTY STILL EXISTS FOR THE LATTER HALF OF NEXT WEEK
AS SUBTLE DIFFERENCES IN THE SUBTROPICAL RIDGE POSITION WILL DICTATE
IF AND HOW QUICKLY MOISTURE IS COMPLETELY SCOURED SOUTH OF THE
FORECAST AREA. MESOSCALE PROCESSES AND OUTFLOW FROM SONORAN MCS/S
MAY ALLOW FOR GULF SURGES AND BOUNDARY LAYER MOISTURE
ADVECTION...BUT DEFINITIVELY FORECASTING AND TIMING SUCH EVENTS
WOULD PROVE FRUITLESS AT THIS TIME. REGARDLESS...H5 HEIGHT RISES AOA
590DM WILL RESULT IN TEMPERATURES PEAKING BACK ABOVE NORMAL UNDER
GRADUALLY MORE COMPRESSIONAL SUBSIDENT FLOW.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
SCT-BKN MID CLOUDS AOA 10KFT CAN BE EXPECTED THIS THIS EVENING AND
OVERNIGHT...WITH SOME PARTIAL CLEARING OF DEBRIS CLOUDS BY SATURDAY
MORNING. UPPER LEVEL DISTURBANCE WILL KEEP POTENTIAL FOR ISOLATED TO
WIDELY SCATTERED THUNDERSTORMS UNTIL ABOUT 08Z TONIGHT. WITH THE
STORMS COMES THE THREAT FOR GUSTY OUTFLOWS AND LOCAL BLOWING DUST TO
IMPACT TERMINALS ALTHOUGH CONFIDENCE TOO LOW TO INTRODUCE WIND SHIFTS
OR REDUCTIONS IN VISIBILITY IN THE TAFS AT THIS TIME.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
SURFACE WINDS WILL CONTINUE TO FAVOR SOUTH AT KBLH...BECOMING
WESTERLY AT KIPL SOMETIME AFTER 03Z THIS EVENING. SKIES GENERALLY
CLEAR WITH A FEW MID-HIGH CLOUDS DURING PERIOD. ANTICIPATE STORM
ACTIVITY WILL BE ISOLATED AND CONFINED TO AREAS EAST OF THE LOWER
COLORADO RIVER VALLEY.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
STORM CHANCES WILL CONTINUE OVER SOUTH-CENTRAL ARIZONA BEFORE
TRENDING DOWN SIGNIFICANTLY WEDNESDAY. HUMIDITIES WILL ALSO BEGIN TO
TREND DOWN FROM WEST TO EAST ACROSS THE ENTIRE FORECAST AREA NEXT
WEEK...BEGINNING AS EARLY AS MONDAY. A GRADUAL WARMING TREND WILL
ENSUE DURING THE PERIOD CLIMBING TO SEVERAL DEGREES ABOVE NORMAL BY
NEXT THURSDAY.
&&
.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT CONDITIONS ACCORDING TO STANDARD
OPERATING PROCEDURES.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...CB/MO
AVIATION...MEYERS
FIRE WEATHER...MEYERS
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
155 PM MST FRI SEP 4 2015
.SYNOPSIS...
SUFFICIENT MOISTURE WILL REMAIN OVER MUCH OF ARIZONA TODAY PROVIDING
GOOD SHOWER AND THUNDERSTORM CHANCES...PARTICULARLY ACROSS THE
EASTERN HALF OF THE STATE. SOMEWHAT DRIER AIR WILL MOVE INTO THE
REGION OVER THE WEEKEND...REDUCING RAINFALL CHANCES VERY SLIGHTLY.
WHILE SOME THUNDERSTORM CHANCES WILL PERSIST DURING THE FIRST HALF
OF NEXT WEEK...A SUBSTANTIALLY WARMER AND DRIER AIRMASS WILL SPREAD
INTO THE AREA FOR THE LATTER HALF OF THE WEEK.
&&
.DISCUSSION... RELATIVELY STRONG UPPER LEVEL TROF REMAINS SITUATED
ALONG THE PAC NORTHWEST COAST EARLY THIS AFTERNOON PUTTING ARIZONA
UNDER SOUTHWEST FLOW ALOFT. IR IMAGERY AT 1 PM SHOWED TS KEVIN OFF
THE SOUTHWEST TIP OF BAJA CA...AND THE SOUTHWEST FLOW WAS TAPPING
INTO THE MID/HIGH LEVEL MOISTURE BEING SHED OFF OF KEVIN. MUCH OF
THIS MOISTURE HAS OVERSPREAD THE EASTERN HALF OF AZ. MORNING
SOUNDINGS SHOWED A MOIST BUT NOT ESPECIALLY UNSTABLE AIRMASS ACROSS
SOUTH CENTRAL AZ WITH PWAT VALUES NEAR 1.5 INCHES BUT RATHER SKINNY
AND MEAGER CAPE. LOW CAPE VALUES WERE DUE TO THE MODEST LAPSE RATES
AND RATHER MOIST ADIABATIC PROFILES AS SEEN IN THE 12Z RAOBS.
STEERING FLOW THIS AFTERNOON AND EVENING WILL BE SOUTHWESTERLY...AND
THE UPPER STREAMLINES DEPICT A LAMINAR AND SLIGHTLY CONFLUENT
FLOW...NOT CONDUCIVE TO STRONG STORM DEVELOPMENT. DYMAMICALLY
SPEAKING...THERE WILL BE WEAK RIPPLES MOVING IN THE SOUTHWESTERLY
FLOW BUT NO STRONG SHORT WAVES APPEAR READY TO MOVE ACROSS ARIZONA
LATER TODAY. HOWEVER THERE IS A JET STREAK RACING ACROSS CENTRAL
AZ...PUTTING THE CENTRAL DESERTS UNDER THE FAVORABLE RIGHT REAR
QUADRANT LATER THIS AFTERNOON.
AT 1 PM SURFACE DEWPOINTS OVER THE CENTRAL DESERTS WERE ELEVATED AND
MOSTLY RANGED FROM THE UPPER 50S TO LOW 60S. WITH MOISTURE ELEVATED
AND INSTABILITY LIMITED...AND DYNAMICS BEING A MIXED BAG...IT IS
TOUGH TO SAY JUST HOW THE CONVECTION WILL PLAY OUT TODAY. SOME
MESOSCALE HI RES MODELS SUCH AS THE HRRR AND WRF4KM SUGGEST WE WILL
SEE STORMS IN THE PHOENIX AREA TONIGHT. AS SUCH WE WILL KEEP ABOUT A
30 PERCENT CHANCE FOR SHOWERS AND THUNDERSTORMS ACROSS SOUTH CENTRAL
ARIZONA LATER THIS AFTERNOON AND OVERNIGHT TONIGHT.
FOR THIS WEEKEND...UPPER TROFFING REMAINS SITUATED ALONG THE WEST
COAST AND ARIZONA WILL STAY UNDER A SOUTHWEST FLOW ALOFT.
HOWEVER...LATEST GUIDANCE DOES NOT REALLY DRY OUT THE EASTERN HALF
OF THE STATE...ESPECIALLY IN THE LOWER LEVELS. PWAT VALUES ARE
FORECAST TO REMAIN NEAR OR ABOVE 1.5 INCHES OVER SOUTH CENTRAL
ARIZONA THROUGH SUNDAY...EVEN THOUGH MUCH OF THE MOISTURE FROM KEVIN
WILL HAVE ALREADY LIFTED OUT TO THE NORTHEAST BY SATURDAY EVENING.
AGAIN...DYNAMICS NOT ESPECIALLY IMPRESSIVE EITHER DAY BUT THERE WILL
LIKELY BE WEAK DISTURBANCES MOVING THROUGH THE SOUTHWEST FLOW FROM
TIME TO TIME...INCREASING THE THREAT FOR SHOWERS OR STORMS.
STREAMLINES REMAIN RATHER LAMINAR AND SOUTHWESTERLY...SIMILAR TO
WHAT IS SEEN TODAY. WE FEEL IT IS A BIT OPTIMISTIC TO REMOVE THE
THREAT FOR CONVECTION FROM THE FORECAST THIS WEEKEND...SO WE WILL
RAISE POPS SLIGHTLY AND KEEP SOUTH CENTRAL AZ UNDER AT LEAST A
SLIGHT CHANCE FOR AFTERNOON/EVENING STORMS BOTH SATURDAY AND SUNDAY.
CONVECTIVE POTENTIAL FOR EARLY NEXT WEEK MAY BE SOMEWHAT MORE MUTED
THAN RECENT DAYS AS DEEP LAYER WINDS VEER SOMEWHAT MORE WESTERLY AS
TROUGHING TRANSLATES INTO THE GREAT BASIN AND NRN ROCKIES.
STILL...BOUNDARY LAYER MOISTURE WILL BE DIFFICULT TO COMPLETELY
SCOUR OUT AND SOME MODEST INFUSION OF MIDLEVEL MOISTURE PEELING OFF
THE REMNANTS OF KEVIN MAY BE POSSIBLE. HOWEVER...THERE REMAINS SOME
DISCONNECT WITH THE MORE QUALITY TROPICAL MOISTURE TO THE
SOUTH...AND THE BEST WV TRANSPORT MAY BE DEFLECTED AROUND THE
FORECAST AREA. IN ADDITION...WITH MID LATITUDE TROUGHING LIFTING TO
THE NORTH AND HEIGHTS ALOFT RISING AHEAD OF THE REMNANT TROPICAL
SYSTEM...MODELS DEPICT SUBSTANTIAL MIDLEVEL WARMING AND INCREASED
CONVECTIVE INHIBITION. KEPT SOME MODEST NEAR CLIMATOLOGY POPS
THROUGH TUESDAY...HOWEVER MEASURABLE RAINFALL AT LOWER DESERT
ELEVATIONS MAY BE DIFFICULT TO COME BY.
SOME MINOR UNCERTAINTY STILL EXISTS FOR THE LATTER HALF OF NEXT WEEK
AS SUBTLE DIFFERENCES IN THE SUBTROPICAL RIDGE POSITION WILL DICTATE
IF AND HOW QUICKLY MOISTURE IS COMPLETELY SCOURED SOUTH OF THE
FORECAST AREA. MESOSCALE PROCESSES AND OUTFLOW FROM SONORAN MCS/S
MAY ALLOW FOR GULF SURGES AND BOUNDARY LAYER MOISTURE
ADVECTION...BUT DEFINITIVELY FORECASTING AND TIMING SUCH EVENTS
WOULD PROVE FRUITLESS AT THIS TIME. REGARDLESS...H5 HEIGHT RISES AOA
590DM WILL RESULT IN TEMPERATURES PEAKING BACK ABOVE NORMAL UNDER
GRADUALLY MORE COMPRESSIONAL SUBSIDENT FLOW.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
SCT-BKN MID CLOUDS...AOA FL100...CAN BE EXPECTED THIS MORNING WITH
POSSIBLY AN EMBEDDED LIGHT SHOWER. THE SOUTHERN END OF AN UPPER
TROUGH WILL HELP REDEVELOP STORM ACTIVITY OVER ARIZONA AGAIN THIS
AFTERNOON. CONFIDENCE TOO LOW AT THIS POINT TO INSERT TSRA IN
PREVAILING WEATHER OR IN TEMPO GROUPS IN THE TAFS.
OTHERWISE...SURFACE WINDS WILL FAVOR SOUTHEAST AND SOUTH FOR MUCH OF
THE DAY.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
ANTICIPATE FAMILIAR WARM SEASON SURFACE WIND PATTERNS...FAVORING
SOUTHERLY DIRECTIONS. ANY STORM ACTIVITY WILL BE ISOLATED AND
CONFINED TO AREAS EAST OF THE LOWER COLORADO RIVER VALLEY. OTHERWISE
ANTICIPATE ONLY SOME SCATTERED MID TO HIGH LEVEL CLOUDS.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SUNDAY THROUGH THURSDAY...
STORM CHANCES WILL CONTINUE OVER SOUTH-CENTRAL ARIZONA THROUGH
TUESDAY BEFORE TRENDING DOWN SIGNIFICANTLY BEGINNING WEDNESDAY.
HUMIDITIES WILL BEGIN TRENDING DOWN FROM WEST TO EAST NEXT
WEEK...BEGINNING AS EARLY AS MONDAY. A GRADUAL WARMING TREND WILL
CONTINUE NEXT WEEK CLIMBING TO SEVERAL DEGREES ABOVE NORMAL BY NEXT
THURSDAY.
&&
.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT CONDITIONS ACCORDING TO STANDARD
OPERATING PROCEDURES.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...CB/MO
AVIATION...AJ
FIRE WEATHER...AJ
AREA FORECAST DISCUSSION
NWS TUCSON AZ
955 PM MST THU SEP 3 2015
.SYNOPSIS...SCATTERED MAINLY AFTERNOON AND EVENING THUNDERSTORMS
WILL OCCUR ESPECIALLY FROM TUCSON EAST AND SOUTH INTO EARLY
NEXT WEEK. EXPECT REDUCED THUNDERSTORM CHANCES BY NEXT WEDNESDAY.
BELOW NORMAL DAYTIME TEMPERATURES WILL PREVAIL THROUGH THIS
WEEKEND...THEN HIGH TEMPERATURES RETURNING CLOSE TO SEASONAL NORMALS
BY THE MIDDLE OF NEXT WEEK.
&&
.DISCUSSION...DRY CONDITIONS WERE ONGOING ACROSS SE ARIZONA WITH THE
EXCEPTION OF ISOLATED SHOWERS PRODUCING LIGHT RAINFALL ACROSS
CENTRAL/SRN GRAHAM COUNTY. OTHERWISE...IR SATELLITE IMAGERY AND
SURFACE OBSERVATIONS INDICATED MOSTLY CLEAR SKIES ACROSS WRN PIMA
COUNTY...AND PARTLY CLOUDY TO CLOUDY SKIES PREVAILED ELSEWHERE.
PATCHY FOG HAD DEVELOPED DURING ABOUT THE PAST HOUR AS PER THE KOLS
METARS.
BASED ON SATELLITE/RADAR TRENDS AS WELL AS THE 04/00Z NAM12 AND
SEVERAL HRRR SOLUTIONS...HAVE MAINTAINED A SLIGHT CHANCE OF SHOWERS
ACROSS MUCH OF SE ARIZONA THE REST OF TONIGHT. PRECIP-FREE
CONDITIONS WILL CONTINUE ACROSS WRN PIMA COUNTY. HAVE ALSO INCLUDED
PATCHY FOG THRU 15Z FRIDAY FOR ERN PIMA COUNTY AND SANTA CRUZ COUNTY.
QUICK GLANCE AT THE 04/00Z UNIV OF AZ WRF-NAM SUGGESTS MARKEDLY
REDUCED COVERAGE OF SHOWERS/TSTMS VERSUS TODAY. FOR NOW...HAVE
MAINTAINED SCATTERED SHOWERS/TSTMS ACROSS MUCH OF THE AREA FRI
AFTERNOON/EVENING. HIGH TEMPS FRI ARE FORECAST TO BE ABOUT 5-10 DEGS
BELOW NORMAL.
PLEASE REFER TO THE ADDITIONAL SECTIONS FOR FURTHER DETAIL.
&&
.AVIATION...VALID THRU 05/06Z.
ISOLATED -SHRA INTO EARLY FRIDAY MORNING FOLLOWED BY SCATTERED
-TSRA/-SHRA FROM LATE FRIDAY MORNING INTO FRIDAY EVENING. MVFR
CONDITIONS AND LOCAL IFR CONDITIONS WILL OCCUR WITH THE STRONGER
TSRA. EXPECT VISIBILITIES REDUCED AS LOW AS 1/2SM IN FOG IN THE
VICINITY OF THE KOLS TERMINAL THRU AROUND 15Z FRIDAY. THERE IS ALSO
A SLIGHT CHANCE OF REDUCED VISIBILITIES PERHAPS TO AROUND 3SM AT
KTUS THRU 15Z FRIDAY. HOWEVER...FORECAST CONFIDENCE OF THIS
OCCURRENCE IS TOO LOW TO INCLUDE IN THE TAFS. OTHERWISE...CLOUD
DECKS WILL GENERALLY RANGE FROM 10-15K FT AGL AND SURFACE WIND WILL
GENERALLY BE LESS THAN 10 KTS. AVIATION DISCUSSION NOT UPDATED FOR
TAF AMENDMENTS.
&&
.FIRE WEATHER...EXPECT SCATTERED MAINLY AFTERNOON AND EVENING
THUNDERSTORMS INTO EARLY NEXT WEEK. LOCALLY HEAVY RAINFALL AND
BRIEF GUSTY WINDS WILL ACCOMPANY THE STRONGER THUNDERSTORMS. TYPICAL
THUNDERSTORM GUSTS WILL BE 25-35 MPH WITH STRONGER STORMS GUSTING TO
OVER 50 MPH. OUTSIDE OF THUNDERSTORM GUSTS...20-FT WINDS WILL BE
TERRAIN DRIVEN AND MAINLY LESS THAN 15 MPH INTO NEXT WEEK. ISOLATED
TO SCATTERED MAINLY AFTERNOON AND EVENING THUNDERSTORMS WILL THEN
PREVAIL BY THE MIDDLE OF THE UPCOMING WEEK.
&&
.PREV DISCUSSION /245 PM MST/...DEEP MOISTURE PLUME IS EXPECTED TO
CONTINUE TO STREAM NORTHEAST INTO SOUTHERN ARIZONA OFF OF TROPICAL
STORM KEVIN ON FRIDAY WITH ADDITIONAL WEAK EMBEDDED IMPULSES
FORECASTED TO MOVE THROUGH THE AREA. THIS WILL CONTINUE THE HIGH END
SCATTERED POP CHANCES FOR FRIDAY AFTERNOON/EVENING. GIVEN THE
EXPECTED CLOUD COVER...MOISTURE...AND PRECIPITATION CHANCES
FRIDAY...AFTERNOON HIGH TEMPERATURES WILL BE NEARLY 10 DEGREES BELOW
SEASONAL AVERAGES...WITH HIGHS IN THE TUCSON METRO AREA EXPECTED TO
TOP OUT IN THE UPPER 80S.
AFTER FRIDAY...THE MODEL SOUNDINGS INDICATE LOWERING ATMOSPHERIC
MOISTURE THROUGH EARLY NEXT WEEK...WITH CORRESPONDING PRECIPITATION
CHANCES FALLING BACK INTO THE ISOLATED TO SCATTERED RANGE. READINGS
WILL WARM A COUPLE OF DEGREES EACH DAY IN THE SATURDAY THROUGH
MONDAY TIME FRAME...WITH DAYTIME HIGH TEMPERATURES NEAR NORMAL BY
EARLY NEXT WEEK. BY MID TO LATE NEXT WEEK...THE MODELS MOVE THE
UPPER HIGH OFF THE CALIFORNIA COAST...WITH A DRYING WESTERLY FLOW
ACROSS THE FORECAST AREA.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
345 PM MDT FRI SEP 4 2015
.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 18Z TAFS THROUGH 18Z SATURDAY NOON)
ISSUED AT 1150 AM MDT FRI SEP 4 2015
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS CONTINUES THROUGH
ABOUT 04Z THIS EVENING. ALL TAF SITES WILL BE AFFECTED BY THE
STORMS THOUGH THE SOUTHERN HALF OF THE AREA WILL HAVE THE HIGHER
AREAL COVERAGE. MOUNTAINS WILL BE FREQUENTLY OBSCURED. KTEX AND
KDRO KASE KEGE HAVE ABOUT 60 PERCENT CHANCE OF MVFR CIGS AND VSBYS
IN STRONGER SHOWERS.
AFTER 04Z SHOWERS AND THUNDERSTORMS WILL DECREASE...THEN STORMS
OVER THE SOUTHERN HALF OF THE AREA WILL INCREASE AGAIN AFTER ABOUT
09Z AS ANOTHER DISTURBANCE MOVES IN FROM AZ AND NM.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...JOE/TGR
LONG TERM...TGR
AVIATION...CC/JOE
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
712 PM EDT SAT SEP 5 2015
.SYNOPSIS...
HIGH PRESSURE WILL BE OVER THE NORTHEASTERN STATES THROUGH THE
WEEKEND. A WEAK COASTAL TROUGH WILL MOVE INLAND THE FIRST HALF OF
NEXT WEEK BEFORE DISSIPATING. ATLANTIC HIGH PRESSURE WILL REBUILD
FOR THE MIDDLE AND LATTER PART OF NEXT WEEK. A COLD FRONT COULD
APPROACH THE AREA NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
DIURNALLY DRIVEN CONVECTION IS STEADILY WANING AND THIS WILL
CONTINUE THROUGH SUNSET. MODELS ARE SIMILAR IN SHOWING STRONG
LOW-LEVEL CONVERGENCE REDEVELOPING ACROSS THE COASTAL COUNTIES AND
ADJACENT WATERS AFTER MIDNIGHT AS THE PRESSURE GRADIENT TIGHTENS
BETWEEN HIGH PRESSURE TO THE NORTH AND LOWER PRESSURE WELL
OFFSHORE. THE LATEST RAP SURFACE MOISTURE FLUX CONVERGENCE PROGS
SHOW CONVERGENCE VALUES INCREASING TO 50-100 G/KG/12HR WHICH IS
IS MORE THAN SUFFICIENT TO SUPPORT THE REDEVELOPMENT OF ISOLATED
TO SCATTERED SHOWERS/TSTMS. IN FACT...SOME GUIDANCE SUGGESTS EVEN
HIGHER COVERAGE COULD OCCUR...MAINLY ALONG THE BEACHES AND OVER
THE COASTAL WATERS.
DEBRIS CLOUDINESS WILL THIN WITH TIME BUT CHANCES FOR
STRATOCUMULUS WILL INCREASE AFTER MIDNIGHT...ESPECIALLY OVER THE
COASTAL COUNTIES. LOW STRATUS COULD ALSO OOZE IN FROM THE
NORTHEAST AND AFFECT INTERIOR PORTIONS OF SOUTHEAST
GEORGIA...ESPECIALLY IN THE WALTERBORO-MONCKS CORNER CORRIDOR.
WILL HAVE TO WATCH THIS CAREFULLY AS SOME OF THIS COULD TRANSITION
TO FOG PRIOR TO SUNRISE. LOWS FROM THE LOWER 70S INLAND WITH MID-
UPPER 70S COAST LOOK ON TRACK.
FOR THE LATE EVENING UPDATE...INCREASED OVERNIGHT POPS TO 40
PERCENT FOR COASTAL AREAS WITH 20 PERCENT REACHING AS FAR INLAND
AS NORTH CHARLESTON-BEAUFORT-BLOOMINGDALE-TOWNSEND. HIGHER POPS
MAY BE NEEDED WITH THE LATE EVENING UPDATE IF THE HIGHER
RESOLUTION MODELS SHOW A MORE CONSISTENT UPTICK OVER THE NEXT FEW
HOURS. ALSO ADJUSTED HOURLY TEMPERATURE AND DEWPOINTS TO MATCH
GOING TRENDS.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
SUNDAY...AT THE SURFACE...NORTHEAST FLOW BETWEEN HIGH PRESSURE EAST
OF THE APPALACHIANS AND A DEVELOPING COASTAL TROF WILL CONTINUE TO
FEED LOW LEVEL MOISTURE INTO THE REGION. MEANWHILE...AS THE CENTER
OF AN UPPER LOW RETROGRADES SLOWLY SOUTHWESTWARD TO THE NORTHEASTERN
GULF COAST...THE MID LEVEL FLOW WILL TURN TO THE SOUTHEAST AND
SOUTH...ALLOWING AN INJECTION OF TROPICAL MOISTURE TO DEVELOP. THE
COMBINATION OF THE TWO WILL ALLOW PWS TO INCREASE TO BETWEEN 1.75
AND 2 INCHES BY AFTERNOON...SUPPORTING SCATTERED DIURNAL SHOWERS AND
THUNDERSTORMS. THE TYPICAL DIURNAL TREND WOULD SUPPORT CONVECTION
ALONG THE COAST AND OFFSHORE IN THE MORNING...GRADUALLY MOVING
INLAND AS THE WINDS ALONG THE COAST VEER A LITTLE AND CAUSE THE SEA
BREEZE TO MOVE INLAND. THE GENERAL CYCLONIC FLOW ALOFT ALSO WILL
PROMOTE SYNOPTIC SCALE LIFT...AIDING THE CONVECTION. I DID INCREASE
THE POPS IN CONCERT WITH THE INCREASE IN GUIDANCE...ALTHOUGH I AM
NOT AS AGGRESSIVE AS THE MET NUMBERS. MAX TEMPS WILL BE
SEASONABLE...IN THE 80S.
SUNDAY NIGHT...THE UPPER LOW WILL SLIDE A BIT FURTHER SOUTHWEST AND
INTO THE NORTHEAST GULF BY MORNING. WITH THE REGION ON THE FAVORED
EAST SIDE OF THE UPPER LOW...I EXPECT THERE TO BE A FAIR AMOUNT OF
CONVECTIVE DEVELOPMENT OVER THE COASTAL WATERS LATE...GRADUALLY
MOVING TOWARD THE COASTLINE.
MONDAY...I EXPECT SIMILAR WEATHER TO SUNDAY FOR THE HOLIDAY AS THE
OVERALL PATTERN CHANGES LITTLE. DEEP MOISTURE WILL BE IN
PLACE...ALLOWING THE CONVERGENCE BOUNDARY NEAR THE COAST TO WORK ITS
WAY INLAND DURING THE DAY...PROVIDING THE MAIN FOCUS FOR SHOWERS AND
THUNDERSTORMS.
TUESDAY...AS THE UPPER LOW CONTINUES TO DRIFT FURTHER SOUTHWEST INTO
THE WESTERN GULF...THE SYNOPTIC SUPPORT FOR CONVECTION WILL DECREASE
A LITTLE. HOWEVER...WITH A LITTLE MORE SUN...TEMPERATURES WILL GET A
COUPLE OF DEGREES WARMER BY AFTERNOON...INCREASING THE AVAILABLE
ENERGY FOR AFTERNOON CONVECTION. THEREFORE...I HAVE MAINTAINED
SCATTERED THUNDERSTORMS IN THE FORECAST. WITH MORE SUN...WE COULD
ALSO SEE SOME INLAND LOCATIONS GET UP TO 90 OR A LITTLE ABOVE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
A MID/UPPER LVL LOW OVER THE SOUTHEASTERN UNITED STATES WILL
GRADUALLY WEAKEN BUT A BROAD TROUGH WILL PERSIST INTO LATE WEEK. AT
THE SFC...BERMUDA HIGH PRESSURE WILL SETTLE OVER THE WESTERN
ATLANTIC WHILE A WEAK TROUGH DEVELOPS INLAND. THE PATTERN WILL
RESEMBLE ONE MORE TYPICAL DURING THE SUMMERTIME...WITH AFTERNOON
SHOWERS AND THUNDERSTORMS. MODELS SUGGEST A WETTER PATTERN NEXT
WEEKEND WITH THE APPROACH OF COLD FRONT FROM THE WEST/NORTHWEST. IN
GENERAL...AFTERNOON HIGHS WILL RANGE IN THE LOWER 90S AWAY FROM THE
COAST. OVERNIGHT LOWS WILL RANGE IN THE LOW TO MID 70S.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
VFR FOR THE OVERNIGHT PERIOD. HOWEVER...THERE ARE SIGNALS THAT
STRATUS COULD DEVELOP WEST OF THE TERMINALS AFTER 08Z. THE LATEST
RAP IS MUCH MORE EMPHATIC IN SHOWING LOW STRATUS REACHING FAR
ENOUGH EAST TO AFFECT BOTH KCHS AND KSAV...BUT THE NAM IS MUCH
MORE CONSERVATIVE. GIVEN TRENDS NOTED THIS MORNING...PREFER TO
STICK WITH THE CONSERVATIVE NAM ATTM. THE RISK FOR SHOWERS/TSTMS
WILL INCREASE AT THE COAST AFTER 04Z AS LOW-LEVEL CONVERGENCE
INCREASES...BUT CURRENT INDICATIONS ARE THE BULK OF THIS ACTIVITY
WILL REMAIN EAST OF THE TERMINALS. WILL KEEP BOTH TERMINALS RAIN-
FREE FOR NOW. SCATTERED SHOWERS/TSTMS WILL AFFECT THE REGION
SUNDAY. SOME OF THESE WILL LIKELY IMPACT KCHS/KSAV DURING THE
DAY...BUT THE DEGREE AND TIMING OF IMPACTS CAN NOT BE SOLIDIFIED
ENOUGH THIS FAR OUT TO JUSTIFY A MENTION ATTM. THIS WILL BE
REEVALUATED WITH LATER TAF CYCLES AS CONFIDENCE INCREASES.
EXTENDED AVIATION OUTLOOK...WHILE FOG IS NOT EXPECTED NEXT
WEEK...THERE COULD BE A PERIOD OF LOW CLOUDS NEAR THE TERMINALS EACH
MORNING WITH THE INCREASE IN LOW LEVEL MOISTURE. ONCE THE LOWER DECK
CLEARS...THE REMAINDER OF THOSE DAYS WILL SEE SCATTERED CONVECTION
THAT COULD TEMPORARILY CAUSE DETERIORATED CONDITIONS AT BOTH
TERMINALS.
&&
.MARINE...
TONIGHT...HIGH PRESSURE OVER NEW ENGLAND WILL CONTINUE TO DRIVE A
PREVAILING NORTHEAST FLOW ACROSS THE LOCAL WATERS THROUGH TONIGHT.
THE GRADIENT WILL TIGHTEN UP AND SUPPORT WIND SPEEDS GENERALLY IN
THE 10-15 KT RANGE. SEAS WILL PERSIST IN THE 1-2 FT RANGE...WITH
SOME 3 FOOTERS POSSIBLE AROUND 20 NM IN THE CHARLESTON COUNTY
WATERS.
SUNDAY THROUGH THURSDAY...HIGH PRESSURE WILL BUILD FROM THE NORTH ON
SUNDAY...PRODUCING NORTHEAST WINDS AROUND 15 KTS AND GRADUALLY
BUILDING SEAS UP TO 3 FT. NORTHEAST FLOW WILL CONTINUE INTO MONDAY
WITH MAINLY DAYTIME COASTAL ENHANCEMENTS NEAR A DEVELOPING
SEABREEZE. HOWEVER...WINDS/SEAS ARE EXPECTED TO REMAIN WELL BELOW
SMALL CRAFT ADVISORY LEVELS. SCATTERED TO NUMEROUS THUNDERSTORMS ARE
EXPECTED SUNDAY AND MONDAY DURING THE LATE NIGHT AND MORNING HOURS
DUE TO A WEAK COASTAL TROF. THE FLOW SHOULD WEAKEN AND VEER TO MORE
EASTERLY ON TUESDAY AS HIGH PRESSURE SHIFTS SOUTHWARD. ATLANTIC HIGH
PRESSURE SHOULD THEN REBUILD SOUTH AND EAST OF THE WATERS ON
WEDNESDAY AND THURSDAY...VEERING WINDS TO THE SOUTH-SOUTHWEST.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
ST
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
514 PM CDT FRI SEP 4 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/JAPSER 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 22Z...
* EAST WINDS JUST SHY OF 10 KT BECMG LGT/VRBL THIS EVE.
MTF/KREIN
//DISCUSSION...UPDATED 18Z...
LATEST WEB CAMS NEAR LAKE MICHIGAN AND DOWNTOWN
CHICAGO...HOWEVER...UGN HAS IMPROVED TO MVFR AND PWK HAS IMPROVED
TO VFR. WITH LITTLE EVIDENCE THAT THE IFR CIGS WILL PENETRATE
INLAND VERY FAR...HAVE REMOVED THE IFR CIGS.
SCT TSRA/SHRA ARE DEVELOPING ALONG AN OLD BOUNDARY EXTENDING FROM
SCNTRL WISCONSIN THROUGH NERN IL AND INTO NWRN INDIANA. EXPECT
THAT SCT TS WILL CONTINUE INTO THE EARLY EVENING...BUT REMAIN SCT
ENOUGH TO MAINTAIN THE VCTS MENTION AS CONFIDENCE IN DIRECT IMPACT
A THE TERMINALS IS LOW. ANTICIPATE THAT CONVECTIVE ACTIVITY SHOULD
WANE WITH SUNSET. A WEAK LAKE BREEZE IS STILL EXPECTED TO DEVELOP
THIS AFTERNOON...WITH LGT/VRBL WINDS BECOMING ELY AT LESS THAN 10
KT. WINDS SHOULD BECM LGT/VRBL OVERNIGHT AGAIN.
SATURDAY SHOULD BE RELATIVELY QUIET THROUGH MUCH OF THE
DAY...THOUGH WITH TROUGHING OVER THE CNTRL PLAINS SHIFTING A
LITTLE EAST...WINDS TOMORROW SHOULD BE PREVAILING SLY AT LESS THAN
10 KT. WITH TEMPS EXPECTED TO REACH NEAR 90F AND DEWPOINTS IN THE
UPPER 60S TO LOWER 70S...THERE SHOULD BE ANOTHER CHANCE FOR SCT
TSRA/SHRA AGAIN TOMORROW AFTERNOON.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* MEDIUM-HIGH IN EASTERLY WINDS REMAINING AROUND 8-9 KT THROUGH
00Z.
* HIGH IN ALL OTHER FORECAST ELEMENTS.
MTF/KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...VFR LIKELY.
SUNDAY...SLIGHT CHANCE OF TSRA LATE.
MONDAY THROUGH WEDNESDAY...CHANCE OF TSRA.
THURSDAY...VFR LIKELY.
LENNING
&&
.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.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
315 PM CDT FRI SEP 4 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/JAPSER 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 20Z...
* CHANCE FOR ISOLATED TSRA/SHRA THIS AFTERNOON.
* EAST WINDS LESS THAN 10 KT BECMG LGT/VRBL OVERNIGHT.
KREIN
//DISCUSSION...UPDATED 18Z...
LATEST WEB CAMS NEAR LAKE MICHIGAN AND DOWNTOWN
CHICAGO...HOWEVER...UGN HAS IMPROVED TO MVFR AND PWK HAS IMPROVED
TO VFR. WITH LITTLE EVIDENCE THAT THE IFR CIGS WILL PENETRATE
INLAND VERY FAR...HAVE REMOVED THE IFR CIGS.
SCT TSRA/SHRA ARE DEVELOPING ALONG AN OLD BOUNDARY EXTENDING FROM
SCNTRL WISCONSIN THROUGH NERN IL AND INTO NWRN INDIANA. EXPECT
THAT SCT TS WILL CONTINUE INTO THE EARLY EVENING...BUT REMAIN SCT
ENOUGH TO MAINTAIN THE VCTS MENTION AS CONFIDENCE IN DIRECT IMPACT
A THE TERMINALS IS LOW. ANTICIPATE THAT CONVECTIVE ACTIVITY SHOULD
WANE WITH SUNSET. A WEAK LAKE BREEZE IS STILL EXPECTED TO DEVELOP
THIS AFTERNOON...WITH LGT/VRBL WINDS BECOMING ELY AT LESS THAN 10
KT. WINDS SHOULD BECM LGT/VRBL OVERNIGHT AGAIN.
SATURDAY SHOULD BE RELATIVELY QUIET THROUGH MUCH OF THE
DAY...THOUGH WITH TROUGHING OVER THE CNTRL PLAINS SHIFTING A
LITTLE EAST...WINDS TOMORROW SHOULD BE PREVAILING SLY AT LESS THAN
10 KT. WITH TEMPS EXPECTED TO REACH NEAR 90F AND DEWPOINTS IN THE
UPPER 60S TO LOWER 70S...THERE SHOULD BE ANOTHER CHANCE FOR SCT
TSRA/SHRA AGAIN TOMORROW AFTERNOON.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM CONFIDENCE FOR ISOLD TSRA CHANCES THIS AFTERNOON AND
TOMORROW AFTERNOON...LOW CONFIDENCE IN COVERAGE AND DIRECT
IMPACT ON THE TERMINALS.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...VFR LIKELY.
SUNDAY...SLIGHT CHANCE OF TSRA LATE.
MONDAY THROUGH WEDNESDAY...CHANCE OF TSRA.
THURSDAY...VFR LIKELY.
LENNING
&&
.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.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
300 PM CDT FRI SEP 4 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/JAPSER 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 20Z...
* CHANCE FOR ISOLATED TSRA/SHRA THIS AFTERNOON.
* EAST WINDS LESS THAN 10 KT BECMG LGT/VRBL OVERNIGHT.
KREIN
//DISCUSSION...UPDATED 18Z...
LATEST WEB CAMS NEAR LAKE MICHIGAN AND DOWNTOWN
CHICAGO...HOWEVER...UGN HAS IMPROVED TO MVFR AND PWK HAS IMPROVED
TO VFR. WITH LITTLE EVIDENCE THAT THE IFR CIGS WILL PENETRATE
INLAND VERY FAR...HAVE REMOVED THE IFR CIGS.
SCT TSRA/SHRA ARE DEVELOPING ALONG AN OLD BOUNDARY EXTENDING FROM
SCNTRL WISCONSIN THROUGH NERN IL AND INTO NWRN INDIANA. EXPECT
THAT SCT TS WILL CONTINUE INTO THE EARLY EVENING...BUT REMAIN SCT
ENOUGH TO MAINTAIN THE VCTS MENTION AS CONFIDENCE IN DIRECT IMPACT
A THE TERMINALS IS LOW. ANTICIPATE THAT CONVECTIVE ACTIVITY SHOULD
WANE WITH SUNSET. A WEAK LAKE BREEZE IS STILL EXPECTED TO DEVELOP
THIS AFTERNOON...WITH LGT/VRBL WINDS BECOMING ELY AT LESS THAN 10
KT. WINDS SHOULD BECM LGT/VRBL OVERNIGHT AGAIN.
SATURDAY SHOULD BE RELATIVELY QUIET THROUGH MUCH OF THE
DAY...THOUGH WITH TROUGHING OVER THE CNTRL PLAINS SHIFTING A
LITTLE EAST...WINDS TOMORROW SHOULD BE PREVAILING SLY AT LESS THAN
10 KT. WITH TEMPS EXPECTED TO REACH NEAR 90F AND DEWPOINTS IN THE
UPPER 60S TO LOWER 70S...THERE SHOULD BE ANOTHER CHANCE FOR SCT
TSRA/SHRA AGAIN TOMORROW AFTERNOON.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM CONFIDENCE FOR ISOLD TSRA CHANCES THIS AFTERNOON AND
TOMORROW AFTERNOON...LOW CONFIDENCE IN COVERAGE AND DIRECT
IMPACT ON THE TERMINALS.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...VFR LIKELY.
SUNDAY...SLIGHT CHANCE OF TSRA LATE.
MONDAY THROUGH WEDNESDAY...CHANCE OF TSRA.
THURSDAY...VFR LIKELY.
LENNING
&&
.MARINE...
325 AM CDT
QUIET WEATHER AND GENERALLY LIGHT WINDS PERSIST OVER THE LAKE FOR
MOST OF THE HOLIDAY WEEKEND. WAVES COULD GROW A BIT BY LATE SUNDAY
OR MONDAY ACROSS THE NORTH HALF WITH SUSTAINED SOUTHERLY
FLOW...BUT STABLE CONDITIONS WITH COOL WATER AND WARM AIR WILL NOT
SUPPORT SIGNIFICANT WAVE GROWTH. A COLD FRONT CROSSING THE LAKE
FROM WEST TO EAST EARLY NEXT WEEK WILL BRING A CHANGE TO THIS
PATTERN.
LENNING
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
238 PM CDT FRI SEP 4 2015
.SHORT TERM...
235 PM CDT
THROUGH SUNDAY...
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/JAPSER 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...
350 AM CDT
SATURDAY THROUGH THURSDAY...
THE BIG STORY OVER THE HOLIDAY WEEKEND WILL BE THE CONTINUED
UNSEASONABLY HOT AND HUMID CONDITIONS. MID/UPPER RIDGING WILL
BECOME EVEN MORE PRONOUNCED AS THE WEAK UPPER LOW COMPLETELY
WASHES OUT. THIS WILL MEAN THAT CONVECTIVE DEVELOPMENT WILL BE
ISOLATED AT BEST ON SATURDAY...AS THERE WILL BE SOME MINOR
CAPPING. WEAK LAKE BREEZE INTO ILLINOIS COULD PROVIDE SOME ADDED
LIFT. OVERALL KEPT POPS IN SLIGHT CHANCE RANGE DURING AFTERNOON
SIMILAR TO PREVIOUS FORECAST. HIGHS IN THE UPPER 80S TO LOWER 90S
AND DEWPOINTS IN THE UPPER 60S TO LOWER 70S WILL SUPPORT HEAT
INDEX VALUES IN THE MID TO UPPER 90S. MINOR EXCEPTION EXPECTED TO
BE IMMEDIATE IL SHORE KEPT SLIGHTLY COOLER BY LAKE BREEZE. SUNDAY
HAS THE POTENTIAL TO BE THE HOTTEST DAY OF THIS STRETCH...WITH
SOLIDLY LOW 90S LIKELY AND MID 90S POSSIBLE IN SPOTS THANKS TO 925
MB TEMPS IN 25-27 CELSIUS RANGE. DEWPOINTS COULD BE A COUPLE
DEGREES LOWER...SO CURRENTLY HEAT INDEX VALUES FORECAST ARE
SIMILAR TO SATURDAY. HAVE MAINTAINED DRY FORECAST FIRMLY UNDER
UPPER RIDGE. MINOR UNCERTAINTY IS WHETHER WINDS WILL TURN
SOUTHEAST ENOUGH ALONG IMMEDIATE IL SHORE TO PROVIDE SOME MINOR
COOLING.
ON SUNDAY NIGHT INTO LABOR DAY...A COLD FRONT WILL BE SLOWLY
APPROACHING FROM THE NORTHWEST AS THE UPPER RIDGE FINALLY GETS
SHOVED EAST BY A FAIRLY DEEP TROUGH ALONG THE CANADIAN BORDER.
SUNDAY EVENING LOOKS TO BE DRY AND THEN HAVE CHANCE POPS MAINLY
WEST OF A PERU TO WAUKEGAN LINE OVERNIGHT. THE BOUNDARY WILL TAKE
ITS SWEET TIME MOVING THROUGH ON LABOR DAY MONDAY INTO TUESDAY AND
THEN A WAVE OF LOW PRESSURE LOOKS TO FORM SOMEWHERE OVER THE MID
MS VALLEY ON TUESDAY AND SHIFT EAST INTO WEDNESDAY. HIGH PRESSURE
OVER THE NORTHERN PLAINS WILL NUDGE THE BAROCLINIC ZONE SOUTH ON
WEDNESDAY...BRINGING COOLER AIR IN AND THEN COOLER AND DRIER AIR
FINALLY ON THURSDAY. HAVE LARGELY STUCK WITH CHANCE POPS FROM
BLENDED GUIDANCE...THOUGH SYNOPTIC SETUP WITH SLOW MOVING FRONT
AND WAVE/S OF LOW PRESSURE ALONG IN AND STRONG MOISTURE TRANSPORT
AHEAD THE BOUNDARY COULD SUPPORT SOME HEFTY RAIN TOTALS IN THE
MONDAY THROUGH WEDNESDAY PERIOD IN PERIODIC SHRA/TSRA. LABOR DAY
ITSELF MAY NOT BE A TOTAL WASHOUT...BUT PLAN FOR A CHANCE FOR
SHOWERS/T-STORMS AND GENERALLY WARM AND MUGGY CONDITIONS FOR
OUTDOOR BBQS. IF YOURE LOOKING FORWARD TO SOME MORE AUTUMN-LIKE
TEMPS...THE WHOLE AREA IS EXPECTED TO BE IN THE 70S ON
THURSDAY...WITH ONLY LOW 70S ALONG THE LAKESHORE.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* CHANCE FOR ISOLATED TSRA/SHRA THIS AFTERNOON.
* EAST WINDS LESS THAN 10 KT BECMG LGT/VRBL OVERNIGHT.
KREIN
//DISCUSSION...UPDATED 18Z...
LATEST WEB CAMS NEAR LAKE MICHIGAN AND DOWNTOWN
CHICAGO...HOWEVER...UGN HAS IMPROVED TO MVFR AND PWK HAS IMPROVED
TO VFR. WITH LITTLE EVIDENCE THAT THE IFR CIGS WILL PENETRATE
INLAND VERY FAR...HAVE REMOVED THE IFR CIGS.
SCT TSRA/SHRA ARE DEVELOPING ALONG AN OLD BOUNDARY EXTENDING FROM
SCNTRL WISCONSIN THROUGH NERN IL AND INTO NWRN INDIANA. EXPECT
THAT SCT TS WILL CONTINUE INTO THE EARLY EVENING...BUT REMAIN SCT
ENOUGH TO MAINTAIN THE VCTS MENTION AS CONFIDENCE IN DIRECT IMPACT
A THE TERMINALS IS LOW. ANTICIPATE THAT CONVECTIVE ACTIVITY SHOULD
WANE WITH SUNSET. A WEAK LAKE BREEZE IS STILL EXPECTED TO DEVELOP
THIS AFTERNOON...WITH LGT/VRBL WINDS BECOMING ELY AT LESS THAN 10
KT. WINDS SHOULD BECM LGT/VRBL OVERNIGHT AGAIN.
SATURDAY SHOULD BE RELATIVELY QUIET THROUGH MUCH OF THE
DAY...THOUGH WITH TROUGHING OVER THE CNTRL PLAINS SHIFTING A
LITTLE EAST...WINDS TOMORROW SHOULD BE PREVAILING SLY AT LESS THAN
10 KT. WITH TEMPS EXPECTED TO REACH NEAR 90F AND DEWPOINTS IN THE
UPPER 60S TO LOWER 70S...THERE SHOULD BE ANOTHER CHANCE FOR SCT
TSRA/SHRA AGAIN TOMORROW AFTERNOON.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM CONFIDENCE FOR ISOLD TSRA CHANCES THIS AFTERNOON AND
TOMORROW AFTERNOON...LOW CONFIDENCE IN COVERAGE AND DIRECT
IMPACT ON THE TERMINALS.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...VFR LIKELY.
SUNDAY...SLIGHT CHANCE OF TSRA LATE.
MONDAY THROUGH WEDNESDAY...CHANCE OF TSRA.
THURSDAY...VFR LIKELY.
LENNING
&&
.MARINE...
325 AM CDT
QUIET WEATHER AND GENERALLY LIGHT WINDS PERSIST OVER THE LAKE FOR
MOST OF THE HOLIDAY WEEKEND. WAVES COULD GROW A BIT BY LATE SUNDAY
OR MONDAY ACROSS THE NORTH HALF WITH SUSTAINED SOUTHERLY
FLOW...BUT STABLE CONDITIONS WITH COOL WATER AND WARM AIR WILL NOT
SUPPORT SIGNIFICANT WAVE GROWTH. A COLD FRONT CROSSING THE LAKE
FROM WEST TO EAST EARLY NEXT WEEK WILL BRING A CHANGE TO THIS
PATTERN.
LENNING
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS DES MOINES IA
1206 AM CDT FRI SEP 4 2015
.UPDATE...
ISSUED AT 656 PM CDT THU SEP 3 2015
ISOLATED SHOWER/STORM WORDING HAS BEEN ADDED N CENTRAL TO E
CENTRAL IA. ELEVATED CONVECTION HAS DEVELOPED ON LEADING EDGE OF
WEAK WARM ADVECTION...LIKELY ROOTED FAIRLY HIGH ABOVE 2KM BASED ON
FORECAST SOUNDINGS. HAVE ONLY ADDED A FEW HOURS AT THIS
POINT...BUT MAY HAVE TO EXTEND AS IT MAY MAINTAIN ITSELF INTO THE
NIGHT WITH TYPICAL NOCTURNAL WARM ADVECTION CYCLE.
&&
.SHORT TERM /TONIGHT/...
ISSUED AT 332 PM CDT THU SEP 3 2015
MAIN FORECAST CONCERN WAS FOCUSED ON TEMPERATURES AND FOG
POTENTIAL OVER NORTHERN IOWA. OVERNIGHT LOWS LOOK TO FINALLY REACH
THE CROSSOVER TEMP BY B/T 07-09Z OVER THE NORTH AND LIKELY SEE FOG
DEVELOP DURING THAT TIME FRAME. NAM/SREF SUGGEST FOG DEVELOPING FROM
MOW TO EST AND POSSIBLY AS FAR SOUTH AS HIGHWAY 20. THE CAVEAT IS
A WEAK SHORTWAVE OVER NEBRASKA/SOUTH DAKOTA MAY BRING IN SOME
HIGHER CLOUDS TOWARDS FRIDAY MORNING...SO ONLY MENTIONED PATCHY
FOG ATOM. THE LATEST HRRR (03.18Z) AND EVEN THE GFS HAVE A HINT
OF CONVECTION DEVELOPING OVER THE NORTHWEST TOWARDS FRIDAY MORNING
IN RESPONSE TO THE LAW DEVELOPING AND ASSOCIATED WITH
AFOREMENTIONED WEAK SHORTWAVE. THINKING THE NAM/ECMWF HAS A BETTER
HANDLE ON TIMING AND LOCATION AND LEFT FORECAST DRY.
.LONG TERM /FRIDAY THROUGH THURSDAY/...
ISSUED AT 332 PM CDT THU SEP 3 2015
PATTERN REMAINS SIMILAR THROUGH THE BEGINNING OF THE MID/LONG RANGE
WITH UPPER RIDGING IN PLACE ALOFT WITH A TROUGH DIGGING INTO THE
WESTERN US. A FEW WEAK IMPULSES WILL MOVE JUST TO THE WEST OF THE
CWA WHICH COULD LEAD TO SOME INCREASED CLOUDINESS...BUT OVERALL
CHANCE OF PRECIPITATION IS SMALL SO HAVE A DRY FORECAST INTO
SATURDAY. UPPER LEVEL RIDGE TO FLATTEN SOME OVER THE WEEKEND AS THE
WESTERN US TROUGH LIFTS NORTHEASTWARD INTO SOUTHERN CANADIAN PRAIRIE
PROVINCES BY LATE SUNDAY. SOUTHERLY FLOW WILL INCREASE AHEAD OF THIS
SYSTEM SATURDAY NIGHT INTO SUNDAY...WITH MOISTURE ADVECTION AND
MOISTURE TRANSPORT BECOMING ORIENTED INTO WESTERN IOWA. MAY SEE SOME
STORMS BUBBLE UP ACROSS THE WESTERN/NORTHWESTERN CWA...BUT OVERALL
WIDESPREAD PRECIPITATION CHANCES NOT EXPECTED UNTIL THE PASSAGE OF
THE COLD FRONT ASSOCIATED WITH THE CANADIAN SYSTEM SUNDAY NIGHT.
THIS FRONT WILL ELIMINATE THE CURRENT HOT AND MUGGY CONDITIONS...AS
H85 TEMPS DROP INTO THE TEENS BEHIND THE FRONT. LONG RANGE IN MODELS
IN SOME DISAGREEMENT INTO NEXT WEEK WITH HOW FAST TO PUSH THE FRONT
SOUTH...WITH THE EC HANGING THE FRONT UP ACROSS SOUTHERN IOWA WITH
CHANCES FOR STORMS CONTINUING INTO MONDAY/MONDAY NIGHT. GFS TRIES TO
PUSH IT INTO MISSOURI...WHICH WOULD KEEP IOWA DRIER MONDAY. FULL
WESTERN US TROUGH TO SHOVE EAST TUESDAY WITH THE FRONT LIFTING
BACK NORTHWARD AS A WARM FRONT LATE MONDAY NIGHT/EARLY TUESDAY
BEFORE A STRONGER COLD FRONT PUSHES THROUGH LATE TUESDAY INTO
TUESDAY NIGHT. H85 TEMPS TO DROP ANOTHER CATEGORY INTO THE LOW
TEENS BEHIND THIS FRONT WITH HIGH PRESSURE EXPECTED TO BUILD IN
FOR THE REST OF THE WEEK. THIS SHOULD LEAD TO MAINLY DRY
CONDITIONS FOR MUCH OF WEDNESDAY INTO THE END OF THE WEEK. MODELS
DO HINT AT A WEAK TROUGH CLIPPING NORTHERN IOWA THURSDAY WHICH
COULD BRING SOME SPRINKLES TO MAINLY NORTHEASTERN IOWA. HAVE A
SMALL AREA OF SLIGHT CHANCE POP FOR THIS FEATURE. OTHERWISE
RELEGATED POPS MAINLY TO THE TIME PERIODS WITH THE FRONTAL
PASSAGES WITH TEMPS EXPECTED TO FALL MORE TOWARD OR SLIGHTLY BELOW
THE SEASONAL AVERAGES.
&&
.AVIATION...04/06Z
ISSUED AT 1206 AM CDT FRI SEP 3 2015
ELEVATED CONVECTION CONTINUES TO WEAKLY MAINTAIN ITSELF NEAR
KALO/KMCW/KOTM AND EITHER VCSH OR VCTS WORDING HAS BEEN ADDED AS
APPROPRIATE. ALTHOUGH CONDITIONS FOR RADIATION FOG ARE STILL
SOMEWHAT FAVORABLE...HAVE INCREASED VSBYS TO IFR AT KMCW WITH MORE
MID CLOUDINESS THAN PREVIOUSLY ANTICIPATED POTENTIALLY HOLDING
THINGS BACK. OTHERWISE EXPECT VFR CONDITIONS WITH SCT/BKN MID OR
HIGH LEVEL CLOUDINESS THROUGH MUCH OF FRI AND FRI EVENING.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...SMALL
SHORT TERM...PODRAZIK
LONG TERM...BEERENDS
AVIATION...SMALL
AREA FORECAST DISCUSSION
NWS GOODLAND KS
751 PM MDT SAT SEP 5 2015
.UPDATE...
ISSUED AT 744 PM MDT SAT SEP 5 2015
JUST COMPLETED AN UPDATE. BASED ON CURRENT CONDITIONS AND LATEST
TRENDS MADE SOME ADJUSTMENTS TO THE PRECIPITATION CHANCES THROUGH
THE REST OF THE NIGHT. A COUPLE OF BOUNDARIES ARE CURRENTLY DRAPED
ACROSS THE AREA. ONE SURFACE TROUGH IS OVER THE NORTHWEST CORNER
AND FAR NORTHERN COUNTIES WITH AN OUTFLOW REINFORCED BOUNDARY
EXTENDING FROM FAR WESTERN KANSAS TOWARD THE SOUTHWEST. NORTHERN
PORTION OF THIS BOUNDARY INTERSECTS WITH THE NORTHERN BOUNDARY.
SOME MINOR DEVELOPMENT HAS BEEN NOTED ON THESE BOUNDARIES. LATEST
FEW RUNS OF THE HRRR AND RAP INDICATE CONTINUED ALONG THESE
BOUNDARIES TO THE EAST OF THEM INTO THE OVERNIGHT HOURS. SO
EXPANDED THE SLIGHT CHANCE POPS TO COVER THESE AREAS. ALSO USED
THE RAP TO ADJUST THE WIND FIELD SINCE IT WAS CATCHING THESE
BOUNDARIES VERY WELL. ALSO MADE MINOR ADJUSTMENTS TO THE OVERNIGHT
TEMPERATURE FORECAST.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 1259 PM MDT SAT SEP 5 2015
THE UPPER LOW ROTATING THROUGH IDAHO THIS AFTERNOON WILL CONTINUE
TO LIFT INTO SOUTHERN CANADA BY SUNDAY AFTERNOON WITH A WEAK SHORT
WAVE TROUGH AXIS MOVING THROUGH THE NORTHERN AND CENTRAL ROCKIES
TONIGHT. THIS WILL PULL THE SURFACE LEE TROUGH EXTENDING FROM
EASTERN NEW MEXICO TO THE NEBRASKA PANHANDLE EASTWARD ACROSS THE
FORECAST AREA OVERNIGHT. GUSTY SOUTH WINDS AHEAD OF THE SURFACE
TROUGH ARE EXPECTED TO TURN NORTHWEST BY MID DAY ON SUNDAY ON THE
BACK SIDE OF THE SURFACE TROUGH.
DIURNALLY DRIVEN ISOLATED THUNDERSTORMS ARE DEVELOPING OVER THE
MOUNTAINS THIS AFTERNOON. A THUNDERSTORM OR SHOWER OR TWO CANNOT
BE TOTALLY RULED OUT OVERNIGHT ACROSS THE FORECAST AREA AS STORMS
ARE CARRIED OFF THE ROCKIES AND ACROSS THE PLAINS IN THE SOUTHWEST
FLOW ALOFT. MODELS HINT AT THE SHOWERS BEING MOSTLY ASSOCIATED
WITH THE UPPER SHORT WAVE TROUGH AS IT MOVES ACROSS THE AREA...BUT
MODELS ARE IN POOR AGREEMENT IN COVERAGE AREAS AND PRECIPITATION
AMOUNTS. HAVE GONE DRY WITH CONTINUED WARM TEMPERATURES AS
CONFIDENCE IN ANY LOCATION RECEIVING ANY MEASURABLE PRECIPITATION
IS EXTREMELY LOW.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 245 PM MDT SAT SEP 5 2015
SUNDAY NIGHT-MONDAY NIGHT...EXPECTING SOME DRY AIR ALOFT TO COVER
THE AREA VERY EARLY SUNDAY EVENING BUT AS THE EVENING/OVERNIGHT
PROGRESSES MODELS CONTINUE TO SHOW AN INCREASE FROM THE WEST AND
SOUTHWEST. THIS INCREASE IN MOISTURE APPEARS TO GET TAPPED BY THE
RIGHT REAR QUAD OF UPPER JET TO AT LEAST WARRANT A SLIGHT CHANCE FOR
SHOWERS/ISOLATED THUNDERSTORMS...PRIMARILY AFTER MIDNIGHT FOR THE
WESTERN 2/3 OF THE AREA. FOR MONDAY BETTER MID LEVEL MOISTURE SLOWLY
MOVES EAST BRINGING A DECREASING CHANCE OF THUNDERSTORMS TO THE
AREA. MAY SEE A FEW ISOLATED STORMS OVER FAR EASTERN COLORADO MONDAY
EVENING OTHERWISE WILL BE WATCHING A WEATHER DISTURBANCE DROP
THROUGH THE NORTHEAST 1/3 OR SO OF THE AREA SHORTLY BEFORE
MIDNIGHT...CONTINUING SOUTHEAST THROUGH SUNRISE TUESDAY MORNING.
WILL HAVE SOME SLIGHT CHANCE POPS TO START THINGS OFF.
LOW TEMPERATURES SUNDAY NIGHT IN THE MID 50S WEST TO LOW 60S EAST.
HIGH TEMPERATURES IN THE MID 80S TO LOW 90S WITH LOWS AGAIN IN THE
MID 50S TO LOW/MID 60S. FOR MONDAY NIGHT LOW TEMPERATURES
TUESDAY...NAM/ECMWF BRING DRIER AIR INTO THE AREA FROM THE NORTH
BEHIND A COLD FRONTAL PASSAGE. THERE IS SOME INSTABILITY ASSOCIATED
WITH SOME MAINLY MID LEVEL MOISTURE ALONG/SOUTH OF THE INTERSTATE BY
18Z BUT CIN IS HIGH. AS THE DRIER AIR MOVES IN CIN ERODES FAVORING
THE FAR SOUTHERN PARTS OF THE AREA FOR PERHAPS AN ISOLATED STORM OR
TWO. FOR TUESDAY NIGHT DRY AIR REMAINS ACROSS THE NORTHEAST/EAST 1/2
OF THE AREA WITH A BIT IN THE 700-500 LAYER ACROSS THE
WEST/SOUTHWEST 1/2. NO INSTABILITY TO WORK WITH AS SFC HIGH
INFLUENCING THE AREA AND REALLY DONT SEE MUCH CHANCE IF ANY CHANCE
FOR PRECIPITATION. HIGH TEMPERATURES IN THE LOW TO MID 80S WITH
OVERNIGHT LOWS IN THE LOW 50S TO AROUND 60.
WEDNESDAY...NOT TERRIBLY CONFIDENT IN THE PRECIPITATION CHANCES
GIVEN MODEL DISCREPANCIES REGARDING AVAILABLE MOISTURE. LITTLE
CHANGE MADE TO WHAT WAS INHERITED PER EXTENDED PROCEDURE SO FOR NOW
HIGHS 80-85 WITH LOWS AGAIN MID 50S TO AROUND 60.
THURSDAY...LOW CONFIDENCE FORECAST ONCE AGAIN. MODELS SEEM TO HINT
THAT A WEATHER DISTURBANCE...COLD FRONT AND INCREASING MOISTURE FOR
PRECIPITATION MAY BE HEADED TOWARD THE AREA FROM THE NORTHWEST.
ECMWF IS THE WETTER AND MUCH COLDER COMPARED TO THE GFS. 850MB
TEMPERATURES FROM THE ECMWF SHOW 10-16C FROM NORTHEAST TO SOUTHWEST
WHICH WOULD ONLY SUPPORT 60S FOR MOST OF THE AREA. GFS SHOWING UPPER
TEENS TO MID 20S WHICH IS CLOSER TO THE CURRENT FORECAST OF MID 70S
TO LOW 80S FOR HIGHS. LOW TEMPERATURES IN THE UPPER 40S TO LOW 50S.
FRIDAY...MUCH BETTER AGREEMENT IN THE 850MB TEMPERATURE FORECAST
FROM THE GFS/ECWMF WITH LOW TEENS WEST...UPPER TEENS/NEAR 20C WEST
WHICH SUPPORT HIGHS IN THE UPPER 60S TO MID 70S.
SATURDAY...LOOKING FOR DRY WEATHER WITH AFTERNOON TEMPERATURES
WARMING INTO THE MID 70S TO AROUND 80.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 539 PM MDT SAT SEP 5 2015
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. SURFACE BOUNDARY
CURRENTLY MOVING BACK TO THE NORTHWEST ACROSS THE AREA WITH A
SHORTWAVE TROUGH APPROACHING FROM THE WEST. MODELS DISAGREE ON
WHERE TO PUT THE ISOLATED CONVECTION. CONSIDERING THE LATEST RADAR
AND OBSERVATIONAL TRENDS AND BETTER PERFORMING MESOSCALE
GUIDANCE...MOST OF THE GUIDANCE HAS THE RAINFALL TOO FAR WEST AND
SO DECIDED AT THIS TIME TO LEAVE ANY MENTION OUT OF BOTH SITES
SINCE SHOULD BE TO THE EAST OF THEM.
SOUTHERLY WINDS WILL START OFF GUSTY. SUSTAINED WINDS OF NEAR 16
KNOTS WITH GUSTS NEAR 25 KNOTS ARE EXPECTED UNTIL NEAR 02Z. SOUTH
WINDS WILL CONTINUE UNTIL LATER TONIGHT AND EARLY TOMORROW MORNING
AS A PREFRONTAL TROUGH AND THEN COLD FRONT MOVE THROUGH. THIS WILL
SHIFT THE WINDS TO A WEST TO SOUTHWEST DIRECTION BEFORE BECOMING
GUSTY FROM A NORTHWEST TO NORTH DIRECTION. THESE WINDS WILL
DECREASE LATE IN THE DAY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...LOCKHART
LONG TERM...99
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
502 PM EDT FRI SEP 4 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 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 127 PM EDT FRI SEP 4 2015
EXPECT LOWERING CONDITIONS TONIGHT AS LOW LEVEL MOISTURE MOVES
IN...WITH THE LOWEST CONDITIONS AT KSAW WHERE UPSLOPE FLOW WILL BE
OFF LAKE MICHIGAN. CONDITIONS WILL IMPROVE SATURDAY MORNING AS FOG
AND LOW CLOUDS DISSIPATE.
&&
.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...TITUS
MARINE...TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
318 PM EDT FRI SEP 4 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 THROUGH THURSDAY)
ISSUED AT 452 AM EDT FRI SEP 4 2015
ON SATURDAY...DEEP TROUGH OVER WESTERN CONUS YEILDS BUILDING RIDGE
FM SOUTHERN PLAINS ACROSS REST OF THE EASTERN HALF OF THE CONUS. SFC
FRONT WILL BE ON FRONT EDGE OF TROUGH...RUNNING FM GREAT BASIN INTO
SCNTRL CANADA. SW FLOW ALOFT INTO NORTHERN PLAINS AND UPPER
MISSISSIPPI RIVER VALLEY MAY ALLOW SHORTWAVE WITH SHRA/TSRA TO GRAZE
WESTERN CWA SATURDAY. BEST CHANCES WILL BE OVER WESTERN LK SUPERIOR
CLOSER TO EDGE OF 1000+ J/KG MUCAPE AND WITH WSW STEERING FLOW H85-
H3. DAYTIME HEATING MAY ALSO LEAD TO BUILDUP OF MLCAPES...THOUGH
SOUNDINGS INDICATE MARGINAL MOISTURE TO SUPPORT SHRA/TSRA FM DAYTIME
HEATING ALONE. SLIGHT CHANCES OVER THE WEST WORK ATTM. MAX TEMPS
WELL INTO THE 80S WITH SOUTH WINDS AHEAD OF PLAINS TROUGH AND H85
TEMPS 18-20C. SEVERE POTENTIAL SATURDAY ON LOW SIDE AS EFFECTIVE
SHEAR STAYS MAINLY BLO 30 KTS...THOUGH IT IS SLIGHTLY STRONGER OVER
LK SUPERIOR.
SHORTWAVE WITH SOURCE TO THE NORTH OF TROPICAL STORM KEVIN NEAR BAHA
PENINSULA FORECAST TO TRACK TO NORTHEAST AHEAD OF DEEP TROUGH OVER
WESTERN CONUS. QUITE THE JOURNEY AND PROBABLY WILL BE SOME AFFECTS
FM THE SHORTWAVE AND SMALLER CONVECTIVELY INDUCED SHORTWAVES OVER
THE PLAINS AS MAIN SHORTWAVE INTERACTS WITH 0-3KM MUCAPES 1000-
2000J/KG. SIMILAR TO FRIDAY NIGHT AND SATURDAY...STEERING WINDS
COULD ADVECT SHRA/TSRA DEVELOPING TO THE WEST OF UPPER LAKES OVER
AT LEAST PORTIONS OF CWA. HESITANT TO GET CAUGHT UP IN THE FINER
DETAILS...BUT APPEARS STRONGEST LIFT TRACKS MORE NORTH OF UPR
MICHIGAN ON SUNDAY PER H85-H7 Q-VECTOR CONVERGENCE AND ALSO STAYS
MAINLY SOUTH OF UPR MICHIGAN OVER CNTRL PLAINS CLOSER TO H85 LOW-
LEVEL JET AND THETA-E RIDGE. MLCAPES BUILD UP TO OVER 1000J/KG BUT
HIGHER VALUES ARE MAINLY MN-WI...AND FAR WEST CWA. EFFECTIVE SHEAR
NOT IMPRESSIVE WITH MOST CWA STAYING BLO 25 KTS THROUGH SUN AFTN. A
VERY WARM AND HUMID DAY EXPECTED AS H85 TEMPS SURGE TO 20C BY 18Z-
24Z. UNLESS CLOUDS ARE MORE OF AN ISSUE...INCREASING S-SW WINDS SFC-
H85 AND WARMER TEMPS ALOFT SHOULD RESULT IN TEMPS AROUND 90 DEGREES
MUCH OF THE CWA. COOLER UPR 70S NEAR LK MICHIGAN. GIVEN H85 DWPNTS
13-18C...EXPECT DWPNTS WELL INTO THE 60S AND PROBABLY LOW 70S OVER
AT LEAST WESTERN CWA. THANKFULLY THIS EXTENSIVE HEAT/HUMIDITY WILL
DECREASE INTO MONDAY.
DEEP TROUGH ALOFT MOVES EAST SUNDAY NIGHT WITH SFC LOW DEEPENING
OVER SCNTRL CANADA AND ANOTHER SFC LOW LIFTING OVER NORTHERN
ONTARIO. THE LOW OVER MANITOBA WILL SWING A COLD FRONT ACROSS UPPER
GREAT LAKES SUNDAY NIGHT...AND THIS FRONT SHOULD BE MAINLY EAST OF
CWA AS EARLY AS MONDAY MORNING. MODELS IN DECENT AGREEMENT IN THAT
IDEA. KEPT POPS IN THE LIKELY RANGE AS THE FRONT SWINGS THROUGH
SUNDAY NIGHT. PWATS UP TO 2.0 INCHES ALONG THE FRONT WILL BE NEAR
RECORD VALUES PER SOUNDING PWAT CLIMO FM SPC. STRONG MOISTURE
CONVERGENCE IN VCNTY OF THE FRONT WILL SUPPORT SHRA AND TSRA. IN A
GENERAL SENSE...SEVERE CHANCES DO NOT APPEAR TOO STRONG WITH
ELEVATED CAPES LESS THAN 1000J/KG AHEAD OF FRONT AND 30+ KTS OF DEEP
LAYER SHEAR LAGGING WELL BEHIND SFC-H85 WIND SHIFT. GIVEN THE
ABUNDANCE OF MOISTURE AND FREEZING LEVELS UP TO 14KFT AND CORFIDI
VECTORS UNDER 10 KTS AND SUGGESTING BACKBUILDING POTENTIAL...THINK
HEAVY RAIN IS GOING TO BE THE MAIN HAZARD WITH THE SHRA/TSRA THAT
OCCUR ON SUNDAY NIGHT AND EARLY MONDAY MORNING. CAN NOT RULE OUT
SEVERE POTENTIAL COMPLETELY THOUGH AS 0-1KM SHEAR IS OVER 20 KTS AND
INCREASINGLY PERPENDICULAR TO FRONT MOVING THROUGH. STRONG H85 JET
NOSING IN AHEAD OF FRONT WILL ALSO SUPPORT SOME SEVERE POTENTIAL
WITH PERSISTENT MOISTURE FLUX AND CONVERGENCE. OVERALL THOUGH THINK
THE SEVERE IS A LOWER CHANCE THAN HEAVY RAIN.
FRONT CLEARS KISQ AND KERY BY EARLY MONDAY AFTN. DRY AIR TAKES OVER
FOR THE WEST HALF AS EARLY AS MONDAY MORNING. H85 TEMPS DROP OFF
SOME...BUT SOME AREAS OF CNTRL MAY STILL SNEAK UP TO AROUND 80. 70S
ELSEWHERE WITH DECREASING HUMIDITY...ESPECIALLY WEST.
MINOR CHANCE OF RAIN LATER MONDAY NIGHT INTO TUESDAY...BUT NOW
APPEARS BETTER CHANCES STAY SOUTH OF UPR MICHIGAN ALONG THE FRONT
THAT MOVES THROUGH ON MONDAY. MAIN STORY IN THE TAIL END OF THE
EXTENDED WILL BE COOLER AND DRIER CONDITIONS. LOW TO MID 70S FOR
HIGHS ON TUESDAY. DEEP TROUGHING ALOFT AND CORE OF COOLEST AIR MOVES
ACROSS FOR WEDNESDAY WITH HIGHS IN THE 60S ALL AREAS. LOW 60S NEAR
LK SUPERIOR WITH PARTLY TO MOSTLY CLOUDY SKIES. STAYING COOL ON
THURSDAY WITH MORE 60S EXPECTED. QUITE THE DIFFERENCE FM THE HEAT
AND HUMIDITY IN STORE FOR THIS WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 127 PM EDT FRI SEP 4 2015
EXPECT LOWERING CONDITIONS TONIGHT AS LOW LEVEL MOISTURE MOVES
IN...WITH THE LOWEST CONDITIONS AT KSAW WHERE UPSLOPE FLOW WILL BE
OFF LAKE MICHIGAN. CONDITIONS WILL IMPROVE SATURDAY MORNING AS FOG
AND LOW CLOUDS DISSIPATE.
&&
.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...JLA
AVIATION...TITUS
MARINE...TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
136 AM EDT FRI SEP 4 2015
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 356 PM EDT THU SEP 3 2015
WV IMAGERY AND RAP ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH ALONG
THE WEST COAST AND A DOWNSTREAM RIDGE FROM TEH SRN PLAINS INTO THE
UPPER MS VALLEY. A SHORTWAVE TROUGH OVER LOWER MI...ON THE FORWARD
FLANK OF THE RIDGE...WAS VERY SLOWLY EDING TO THE SE. AT THE SFC...A
RIDGE EXTENDED FROM QUEBEC AND NRN ONTARIO INTO LAKE SUPERIOR
RESULTING IN LIGHT E TO NE FLOW THROUGH UPPER MI. VIS LOOP SHOWED
MOSTLY SUNNY SKIES ACROSS THE NORTH WITH SCT-BKN CU INLAND CNTRL.
TONIGHT...WITH THE LOSS OF DAYTIME HEATING...THE CU WILL FADE
LEAVING MOSTLY CLEAR SKIES. HOWEVER...SOME MID CLOUS AROUND THD
PERSISTENT LOW MAY MOVE BACK INTO THE SE. GIVEN DEWPOINTS IN LOWER
60S...RADIATIONAL COOLING SHOULD DROP MINS TO AROUND 60...COOLEST
OVER THE INLAND WEST HALF. SO...EXPECT AREAS OF FOG ARE LIKELY TO
DEVELOP...ESPECIALLY CNTRL.
FRI...ALTHOUGH THE LOWER MI MID LEVEL LOW SHOULD STILL
LINGER...UPPER MI WILL REMAIN UNDER THE INFLUENCE OF THE SFC RIDGE
WITH MOSTLY SUNNY SKIES AFTER THE MORNING FOG OR LOW CLOUDS BURN
OFF. WITH 850 MB TEMPS AROUND 15C...TEMPS SHOULD CLIMB TO AROUND
80...WITH LOWER READINGS ALONG THE GREAT LAKES.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 317 PM EDT THU SEP 3 2015
MAINLY FOCUSED ON SHOWER AND THUNDERSTORM COVERAGE/INTENSITY SAT
NIGHT INTO MONDAY AND ON CONTINUED HOT/HUMID CONDITIONS SAT AND SUN.
FRI NIGHT LOOKS DRY FOR MOST PART...BUT THERE IS A SLIGHT CHANCE OF
SHOWERS AND THUNDERSTORMS OVER THE W A SHORTWAVE ENERGY MOVES W OF
THE CWA IN THE SW FLOW ALOFT. A SIMILAR SETUP ON SAT...BUT GREATER
CHANCES OF PRECIP OVER THE W. COULD SEE SOME STRONG TO POSSIBLY
SEVERE STORMS...IF CONVECTION DOES DEVELOP...DUE TO 1000-2000 J/KG
OF MUCAPE. 0-6KM SHEAR WILL BE ON THE WEAK SIDE SAT AT ONLY AROUND
20KTS...WHICH LIMITS ORGANIZED SEVERE POTENTIAL.
THE 12Z/03 GFS IS AN OUTLIER FOR SAT NIGHT IN SHOWING PRECIP OVER
THE CENTRAL CWA. THINK THAT MOST OF THE AREA WILL STAY DRY SAT
NIGHT...WITH THE W POSSIBLY SEEING SOME CONVECTION. PRECIP LOOKS TO
STAY OVER THE W HALF ON SUN AS A STRONGER SHORTWAVE MOVES TO THE W.
WIND SHEAR WILL BE GREATER SUN...WITH 0-6KM BULK VALUES AROUND
30KTS...BUT MUCAPES WILL ONLY BE 1000-1500J/KG. TEMPS WILL BE
WARMEST ON SUN AS 850MB TEMPS WILL BE 20-22C...PROMOTING WARMEST
TEMPS AROUND 90 IN DOWNSLOPING AREAS OF NCENTRAL UPPER MI NEAR LAKE
SUPERIOR.
THE COLD FRONT FROM A LOW PRESSURE SYSTEM MOVING ACROSS SRN CANADA
WILL PASS THROUGH THE AREA SUN NIGHT INTO MON MORNING...WHICH WILL
MEAN LIMITED INSTABILITY AND MINIMAL SEVERE POTENTIAL. COVERAGE OF
CONVECTION LOOKS GOOD...WITH MOST LOCATIONS SEEING SOME PRECIP.
MON WILL SEE CLEARING SKIES AND PRECIP EXITING E. THE AIRMASS WILL
BECOME COOLER AND DRIER...BUT 850MB TEMPS ONLY DROP INTO THE MID
TEENS C BY LATE MON. THIS SHOULD RESULT IN HIGHS FROM THE MID 70S TO
LOW 80S.
LOTS OF UNCERTAINTY MID TO LATE NEXT WEEK AS DETAILS OF A TROUGH
DROPPING INTO THE REGION ARE HARD TO PIN DOWN. DOES LOOK COOLER WITH
AT LEAST A SLIGHT CHANCE OF PRECIP.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 136 AM EDT FRI SEP 4 2015
VFR CONDITIONS WILL PREVAIL INITIALLY AT KIWD/KCMX/KSAW. SINCE
DAYTIME HEATING YESTERDAY HELPED MIX OUT SOME OF THE LOW-LEVEL
MOISTURE AND SINCE WINDS JUST OFF THE SFC WILL BE A LITTLE STRONGER
OVERNIGHT THAN IN RECENT NIGHTS...FOG SHOULD NOT BE AS
DENSE/WIDESPREAD AS RECENT NIGHTS. IN ADDITION...SINCE MARINE FOG
HAS CLEARED OFF MOST OF LAKE SUPERIOR AND NORTHERN LAKE MICHIGAN...
ADVECTION OF MARINE FOG WON`T BE A CONTRIBUTOR TO POOR CONDITIONS.
THUS...IT STILL APPEARS FOG OVERNIGHT SHOULDN`T DROP VIS BLO MVFR AT
KCMX/KSAW. HOWEVER...NOT OUT OF THE QUESTION THAT THERE COULD BE A
PERIOD OF IFR AROUND DAYBREAK...ESPECIALLY AT KSAW. LIGHT DOWNSLOPE
WIND AT KIWD MAY WORK TO KEEP THAT TERMINAL VFR THRU THE NIGHT. VFR
CONDITIONS ARE EXPECTED AT ALL TERMINALS FROM MID MORNING INTO AT
LEAST THE EARLY EVENING. FOG WILL PROBABLY MAKE A RETURN NEAR OR
JUST BEYOND THIS FCST PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 356 PM EDT THU SEP 3 2015
AREAS OF FOG PERSISTED ACROSS THE WESTERN THIRD OF THE LAKE AND IS
EXPECTED TO LINGER INTO FRI WITH NE FLOW CONTINUING.
OTHERWISE...NORTHEAST WINDS OF 10-15KT WILL CONTINUE TODAY WITH 1-3
FT WAVES ACROSS THE WEST. THE NEXT CHANCE FOR WINDS GREATER THAN
20KT WILL BE SUNDAY INTO MONDAY AS THE NEXT SYSTEM APPROACHES FROM
THE WEST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...ROLFSON
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1222 AM EDT FRI SEP 4 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 330 PM EDT THU SEP 3 2015
SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE ACROSS LOWER
MICHIGAN THROUGH SATURDAY. THE CLOUDS AND SHOWERS WILL HOLD HIGHS
AROUND 80 FRIDAY BEFORE THE TEMPERATURE CLIMBS BACK TO THE MID 80S
FOR THE REMAINDER OF THE HOLIDAY WEEKEND. COOLER WEATHER IS EXPECTED
BY THE MIDDLE OF NEXT WEEK.
&&
.UPDATE...
ISSUED AT 838 PM EDT THU SEP 3 2015
I UPDATED OUR FORECAST AND GRIDS TO DROP THE MENTION OF
PRECIPITATION OVER MOST OF OUR CWA TONIGHT. AS I SEE IT THE
CONVECTIVE LINE CONTINUES TO SINK SOUTH WITH TIME AND SHOULD BE
OUT OF OUR CWA TOTALLY BY MIDNIGHT. THE RAP MODEL SHOWS THE 700 MB
LOW...CURRENTLY CENTERED NEAR LAKE HURON BY APN...MOVES SLOWLY
WESTWARD...REACHING TO NEAR TVC BY MORNING. THAT KEEPS MOST OF OUR
CWA IN THE DRY WESTERLY FLOW ALL NIGHT LONG. THE DEEP MOISTURE IS
EAST OF LANSING BY 9 PM. THE MOST UNSTABLE CAPE ON THE RAP13
MODEL DROPS SOUTH OVER TIME TOO... WHICH GOES ALONG WITH THE IDEA
OF NO SIGNIFICANT CONVECTION TONIGHT. ONLY AREAS NEAR THE 700 MB
LOW MAY SEE SOME LIGHT WRAP AROUND RAIN SHOWERS (NEAR AND NORTH OF
ROUTE 10).
AS FOR FOG DEVELOPING TONIGHT...THIS COULD BE A SIGNIFICANT
FORECAST ISSUE. THERE IS AN AREA OF THICK LOW CLOUDS DROPPING
SOUTH TO NEAR I-96...AS 0F 8 PM THIS EVENING. DEPENDING ON JUST
HOW FAR SOUTH THEY GET WILL DECIDE HOW DENSE THE FOG GETS TONIGHT.
WITH ALL THE RAIN TODAY AND LIGHT WINDS IF THE SKIES STAYED MOSTLY
CLEAR WE COULD BE LOOKING AT DENSE FOG BY SUNRISE. LIKELY IF THIS
HAPPENS IT WOULD BE NEAR I-94.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 330 PM EDT THU SEP 3 2015
FORECAST CONCERNS DEAL WITH THE CONVECTIVE POTENTIAL THROUGH
SATURDAY.
RADAR IMAGERY SHOWS A COUPLE OF BROKEN LINES OF CONVECTION. THE
FIRST EXTENDS FROM MOUNT PLEASANT WEST TO NEWAYGO COUNTY. THE SECOND
IS FARTHER SOUTH FROM NEAR ST JOHNS TO MIDDLEVILLE. THE SOUTHERN
LINE APPEARS TO BE NEAR A WEAK COLD FRONT THAT IS WASHING OUT.
FARTHER NORTH A WELL DEFINED CIRCULATION ASSOCIATED WITH AN UPPER
LOW THAT WILL LINGER OVER LOWER MICHIGAN THROUGH SATURDAY. SBCAPE
AROUND 2500 J/KG COUPLED WITH SHEAR AROUND 30 KTS IS ENABLING A FEW
STORMS TO BECOME ORGANIZED. AS THE SUN SETS WE/LL LOSE SOME
INSTABILITY AND THE CONVECTION SHOULD WANE A BIT. HOWEVER THE UPPER
LOW/TROUGH WILL LINGER OVER THE CWA THROUGH SATURDAY. SHEAR VALUES
AROUND 15KTS ARE PROGD FRIDAY ACROSS THE CWA SO WE DON/T ANTICIPATE
SVR STORMS BUT CAN`T RULE OUT A STRONG ONE OR TWO DUE TO DECENT
INSTABILITY.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 330 PM EDT THU SEP 3 2015 IMPACT WEATHER IN THE EXTENDED
PERIOD CENTERS AROUND THE SLOW MOVING FRONT THAT MAY BRING COPIOUS
RAINS FROM MONDAY TO EARLY WEDNESDAY.
ONLY A FEW TWEAKS WERE MADE TO THE BLENDED FORECAST...MAINLY TO SLOW
THE FRONT DOWN A BIT EARLY IN THE WEEK PER THE SLOWER 12Z ECMWF THEN
END THE CHANCE FOR POPS LATE WEDNESDAY WHICH THE 12Z GUIDANCE AGREES
ON. GIVEN THE LONG DURATION AND HIGH PWATS...WOULD NOT BE SURPRISED
TO SEE WIDESPREAD 2 TO 3 INCH RAINFALL FROM MONDAY TO EARLY
WEDNESDAY.
TEMPERATURES ON MONDAY WILL BE TRICKY AS HIGH COULD BE ANYWHERE FROM
AROUND 80 TO NEAR 90 DEPENDING ON HOW EXTENSIVE THE CLOUDS ARE. WENT
MIDDLE OF THE ROAD FOR NOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1212 AM EDT FRI SEP 4 2015
TRENDS WILL BE MONITORED FOR FOG DEVELOPMENT NOW THROUGH ABOUT
13Z. CURRENTLY THINKING THE LOW CLOUDS WILL BE MORE OF A PROBLEM
THAN FOG DEVELOPMENT FOR SITES LIKE MKG...GRR...AZO...AND BTL.
MODEL SOUNDINGS ARE NOT BULLISH ON FOG DEVELOPMENT AND EVEN THE
HOURLY LAMP GUIDANCE PRODUCTS ARE BACKING OFF A BIT ON THE VIS
REDUCTIONS. THAT SAID...THERE ARE POCKETS OF FOG NORTH OF LAN
WHERE BREAKS IN THE CLOUDS HAVE OCCURRED. WILL NEED TO KEEP TRACK
OF THE BREAKS OVERNIGHT. LOW CIGS LOOK QUITE LIKELY FOR MOST
LOCATIONS...PROBABLY GETTING DOWN TO A COUPLE HUNDRED FEET. WILL
STILL MENTION SOME LIGHT FOG FOR THE TAFS TO KEEP CONSISTENCY WITH
PREVIOUS THINKING...THOUGH WILL KEEP ABOVE 1/2SM FOR NOW.
&&
.MARINE...
ISSUED AT 330 PM EDT THU SEP 3 2015
WINDS AND WAVES WILL REMAIN ON THE LIGHT SIDE TONIGHT AND FRIDAY DUE
TO THE WEAK PRESSURE GRADIENT. LIGHT NORTH WINDS TONIGHT WILL BECOME
ONSHORE FRIDAY. SCATTERED THUNDERSTORMS ARE POSSIBLE THROUGH
SATURDAY.
&&
.HYDROLOGY...
ISSUED AT 1110 AM EDT THU SEP 3 2015
NO IMMEDIATE CONCERNS TO BE AWARE OF TODAY REGARDING RIVER
FLOODING.
HEAVY RAINFALL ASSOCIATED WITH THUNDERSTORM ACTIVITY WILL QUICKLY
PASS THROUGH THE AREA THIS MORNING AND THROUGH EARLY AFTERNOON.
PONDING MAY OCCUR ON ROADWAYS AND LOW LYING AREAS IN AND AROUND
THE HEAVIER RAINFALL. MUCH OF THE HEAVIER ACTIVITY WILL VACATE
THE REGION BY MID AFTERNOON.
THE NEXT 7 DAYS REMAINS ACTIVE AND INCLUDES MULTIPLE CHANCES FOR
RAIN. 7 DAY AREA AVERAGE RAINFALL OF ONE TO TWO INCHES IS POSSIBLE
WITH LOCALLY HIGHER AMOUNTS IN THE VICINITY OF THUNDERSTORMS.
RECENT DRY WEATHER AND LOW RIVER LEVELS...COUPLED WITH THE
PIECEWISE FASHION OF THE RAINFALL...SHOULD ALLOW FOR THE GROUND TO
SOAK UP MUCH OF THE ONSET OF MOISTURE. RUNOFF THEREAFTER IS
LIKELY TO BE HANDLED WELL BY RIVERS...AS THEY HAVE PLENTY OF ROOM
TO TAKE ON ADDITIONAL WATER.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...04
SHORT TERM...04
LONG TERM...OSTUNO
AVIATION...HOVING
HYDROLOGY...JAM
MARINE...04
AREA FORECAST DISCUSSION
NWS DULUTH MN
712 PM CDT SAT SEP 5 2015
.UPDATE...
ISSUED AT 712 PM CDT SAT SEP 5 2015
HAVE MADE SOME UPDATES TO THE POP FORECASTS TO TRIM BACK
THE POPS OVER NW WISCONSIN AND ARROWHEAD OF MN SOMEWHAT. WE HAVE
BEEN GETTING SOME ISOLATED CONVECTIVE ACTIVITY THERE...BUT OTHERWISE
DO NOT EXPECT ANYTHING THERE UNTIL THE MAIN BODY OF STORMS GET THERE
LATER THIS EVENING. OTHERWISE...FORECAST APPEARS TO BE ON TRACK AT
THIS TIME.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 300 PM CDT SAT SEP 5 2015
FORECAST FOCUS IN THE SHORT TERM WILL BE ON THUNDERSTORM
CHANCES AND THE POTENTIAL FOR STRONG/SEVERE STORMS AND HEAVY
RAINFALL.
LOW PRESSURE OVER THE NORTHERN PLAINS AND A FRONTAL BOUNDARY
EXTENDING NORTHEAST INTO NORTHWEST MINNESOTA THIS AFTERNOON WILL
START TO MOVE EAST TONIGHT AND MORE SO SUNDAY INTO SUNDAY NIGHT.
THE FRONT WILL FINALLY CLEAR OUR EASTERN CWA LATE SUNDAY NIGHT.
THE NORTHLAND WAS PRECIP FREE AS OF LATE AFTERNOON...BUT THIS IS
EXPECTED TO CHANGE AS A SHORTWAVE LIFTS NORTHEAST FROM SOUTH
DAKOTA AND BRUSHES OUR WESTERN CWA. IN ADDITION TO THIS
WAVE...WILL BE A LLJ THAT CONTINUES MOISTURE/WARM ADVECTION
THROUGH THE NIGHT. KFSD/KMPX SHOWED A SOUTHERLY 850MB WIND AT
35KT AND THIS IS EXPECTED TO INCREASE TO 40 TO 45 KT OVERNIGHT.
SPC MESOANALYSIS PAGE SHOWED MLCAPE AROUND 2000J/KG WITH DEEP
LAYER SHEAR LESS THAN 30KT. THE SHEAR WILL INCREASE AS THE
SHORTWAVE MOVES THROUGH AND MID LEVEL FLOW STRENGTHENS. THE RISK
FOR SEVERE STORMS IS NOT PARTICULARLY HIGH TONIGHT...BUT GIVEN THE
INSTABILITY PRESENT A SEVERE STORM CAN NOT BE RULED OUT. A BIGGER
THREAT WILL BE HEAVY RAIN AS WE EXPECT NUMEROUS THUNDERSTORMS TO
FORM AND GIVEN COPIOUS AMOUNTS OF MOISTURE PRESENT...12Z KINL PWAT
OF 1.74" WHICH IS THE HIGHEST REPORTED ON THIS DATE...STORMS WILL
BE CAPABLE OF PRODUCING A PERIOD OF HEAVY RAIN. THE MODELS ARE
STILL NOT IN PARTICULARLY GOOD AGREEMENT REGARDING THE EVOLUTION
OF CONVECTION...BUT WE FEEL CONFIDENT ENOUGH TO GO WITH HIGH POPS
FOR MOST AREAS TONIGHT. HEAVY RAIN FELL LAST NIGHT FROM FAR
NORTHERN CASS COUNTY NORTHEAST INTO PORTIONS OF CENTRAL/NORTHERN
SAINT LOUIS AND KOOCHICHING COUNTIES. WE ISSUED A FLASH FLOOD
WATCH FOR MOST OF THESE AREAS TONIGHT..EXCEPT FOR CENTRAL SAINT
LOUIS COUNTY.
THE STORMS SHOULD DIMINISH IN COVERAGE SUNDAY MORNING AS THE
BETTER FORCING MOVES OUT AND THE LLJ WEAKENS. HOWEVER...WE DO
EXPECT MORE STORMS TO DEVELOP ALONG THE EASTWARD MOVING COLD FRONT
THROUGH THE DAY. A BETTER CHANCE FOR SEVERE STORMS WILL OCCUR IF
ENOUGH CLEARING TAKES PLACE. THERE STILL IS NOT IDEAL LOCATION OF
THE MAX SHEAR AND INSTABILITY...BUT IT WILL BE BETTER THAN WHAT WE
HAVE SEEN THE PAST COUPLE DAYS. THE STORMS WILL ALSO PRODUCE MORE
HEAVY RAIN POSSIBLY LEADING TO LOCALIZED FLOODING.
WE DIMINISH THE CHANCE FOR STORMS FROM WEST TO EAST SUNDAY NIGHT
AS THE FRONT MOVES THROUGH.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 300 PM CDT SAT SEP 5 2015
A SW FLOW ALOFT WILL CONTINUE TO AFFECT THE FORECAST AREA ON MONDAY.
HOWEVER...SFC RIDGING WILL COVER THE AREA. A WEAK UPPER LEVEL TROF
IS PROGGED TO MOVE THROUGH NORTHERN MN MONDAY NIGHT...ALTHOUGH THE
RIDGING REMAINS AT THE SFC. MODEL DIFFERENCES...ESPECIALLY BETWEEN
THE GFS AND ECMWF...HAVE PLACED SOME SMALL POPS OVER THE SE CORNER
OF THE WI FA TO TRY TO BLEND THE MODELS. THE SFC RIDGING PERSISTS ON
TUESDAY. HOWEVER...MODEL DIFFERENCES ARE BECOMING LARGER IN RESPECT
TO A SHORTWAVE`S IMPACT ON THE REGION. HAVE SOME SMALL POPS OVER NW
WI ON TUESDAY AS A RESULT. THE FLOW ALOFT SWITCHES TO A WESTERLY
FLOW WITH HIGH PRESSURE AT THE SFC. WEDNESDAY FINDS THE GEM/GFS IN
AGREEMENT WITH HIGH PRESSURE STILL IN CHARGE. HOWEVER...THE
ECMWF/DGEX WANT TO SEND AN UPPER LEVEL TROF INTO MN BY 00Z THURSDAY
WITH PLENTY OF QPF. USED A CONSENSUS APPROACH WHICH RESULTS IN POPS
ACROSS MUCH OF THE FORECAST AREA. AFTER THE FIRST TROF MOVES AWAY
WEDNESDAY NIGHT...A SECOND ONE QUICKLY REPLACES IT WITH BETTER
AGREEMENT AMONGST THE MODELS. BY 12Z FRIDAY...THE GEM AND ECMWF HAVE
A CUT OFF CLOSED LOW DRIFTING TOWARDS THE REGION WHILE THE GFS/DGEX
HAS A LONG WAVE TROF OVERHEAD. NONETHELESS...WILL CONTINUE TO HAVE
POPS IN PLACE. INSTABILITY PARAMETERS INDICATE SOME ISOLD THUNDER
THURSDAY...BUT JUST SHOWERS THURSDAY NIGHT AND FRIDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 712 PM CDT SAT SEP 5 2015
A SHORTWAVE WILL MOVE THROUGH NORTHWEST MINNESOTA INTO WESTERN
ONTARIO OVERNIGHT AND INTO EARLY SUNDAY MORNING. THIS FEATURE HAS
GENERATED SHOWERS AND STORMS WHICH WILL MOVE EASTWARDS FROM
NORTHWEST MINNESOTA AND IMPACT ALL TERMINALS AS THE NIGHT
PROGRESSES. CIGS WILL LOWER AS THE NIGHT PROGRESSES...BUT STILL
KEPT ALL SITES IN VFR. STILL UNSURE AT THIS POINT IF AN
INDIVIDUAL STORM WILL PASS THROUGH A TERMINAL...BUT TRIED TO GET
THE BEST TIMING FROM CURRENT RADAR TRENDS AND PAST FEW HRRR RUNS.
WITH STORMS PASSING THROUGH BROUGHT VISBY AND CIGS TO MVFR...BUT
SUSPECT LOWER CONDITIONS WILL OCCUR. THIS IS SOMETHING THAT WILL
NEED TO BE CLOSELY MONITORED AS STORMS MOVE IN. KEPT IN LLWS AT
ALL LOCATIONS UNTIL 13Z TO 14Z DUE TO THE LOW LEVEL JET.
THERE WILL BE A LULL IN SHOWERS AND STORMS SUNDAY
MORNING. SUSPECT LOW CIGS WILL STILL BE AROUND KBRD...KINL AND
KHIB AS WAS THE CASE EARLY THIS MORNING. GUSTY WINDS WILL DEVELOP
AROUND 13Z TO 14Z AT ALL TERMINALS. THIS IS DUE TO THE PRESSURE
GRADIENT BEING GENERATED BY THE COLD FRONT MOVING IN FROM THE
WEST. AS THE COLD FRONT MOVES IN DURING THE AFTERNOON AND EVENING
THERE WILL BE ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 67 83 59 76 / 70 70 70 10
INL 64 82 53 75 / 90 70 30 0
BRD 69 85 56 76 / 70 60 30 10
HYR 71 85 60 77 / 60 80 80 10
ASX 69 87 61 77 / 40 70 70 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...FLASH FLOOD WATCH UNTIL 7 AM CDT SUNDAY FOR MNZ010-011-018-025-
026.
LS...NONE.
&&
$$
UPDATE...LE
SHORT TERM...MELDE
LONG TERM...GSF
AVIATION...WL
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
707 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 00Z TAFS through 00Z Sunday Evening)
Issued at 707 PM CDT SAT SEP 5 2015
VFR conditions are expected to persist through the TAF period. While
scattered to broken cirrus may continue to stream eastward through
the region, cumulus will dissipate tonight before re-forming Sunday
by early afternoon. Decreasing southerly winds will begin to increase
again late Sunday morning out of the SSW, then will gust up to 20-22
kts out of the south during the afternoon. A few storms may begin
pushing into far northwest Missouri by the end of the period, but
should stay north of all TAF sites.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
DISCUSSION...Leighton
AVIATION...Laflin
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
813 PM MDT SAT SEP 5 2015
.UPDATE...
UPDATED 1ST PERIOD FORECAST TO DECREASE POPS/QPF BASED ON LATEST
RADAR AND SATELLITE TRENDS. OTHERWISE...FORECAST ON TRACK. NEW
SUITE OF PRODUCTS OUT SHORTLY.
11
&&
.PREV DISCUSSION...555 PM MDT SAT SEP 5 2015...
.AVIATION...
00Z TAF CYCLE
MOISTURE CONTINUING TO STREAM FROM SW TO NE ACROSS NM ON MODERATE
SOUTHWEST WINDS ALOFT. MTS OCCASIONALLY OBSCURED IN SCT SHOWERS
OVER CENTRAL NM WITH SOME MVFR CIGS/VSBYS IN STRONGER SHOWERS/STORMS.
ISOLD ACTIVITY EXPECTED ELSEWHERE. POTENTIAL FOR WIND GUSTS TO
40KT. VAST MAJORITY OF CONVECTION EXPECTED TO DIMINISH SHORTLY
AFTER SUNSET. ON SUNDAY...AFTERNOON SHOWERS AND THUNDERSTORMS
WILL FAVOR THE SOUTHWEST AND SOUTH-CENTRAL MTS.
33
&&
.PREV DISCUSSION...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 MOISTURE 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.
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
11
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
555 PM MDT SAT SEP 5 2015
.AVIATION...
00Z TAF CYCLE
MOISTURE CONTINUING TO STREAM FROM SW TO NE ACROSS NM ON MODERATE
SOUTHWEST WINDS ALOFT. MTS OCCASIONALLY OBSCURED IN SCT SHOWERS
OVER CENTRAL NM WITH SOME MVFR CIGS/VSBYS IN STRONGER SHOWERS/STORMS.
ISOLD ACTIVITY EXPECTED ELSEWHERE. POTENTIAL FOR WIND GUSTS TO
40KT. VAST MAJORITY OF CONVECTION EXPECTED TO DIMINISH SHORTLY
AFTER SUNSET. ON SUNDAY...AFTERNOON SHOWERS AND THUNDERSTORMS
WILL FAVOR THE SOUTHWEST AND SOUTH-CENTRAL MTS.
33
&&
.PREV DISCUSSION...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 MOISTURE 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.
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
11
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
328 PM EDT FRI SEP 4 2015
.SYNOPSIS...
A STRONG RIDGE OF HIGH PRESSURE WILL CONTINUE TO PREVAIL
ACROSS THE NORTH COUNTRY THIS WEEKEND. THIS WILL RESULT IN DRY
CONDITIONS WITH WARM DAYS AND COOL NIGHTS. AN ISOLATED SHOWERS IS
POSSIBLE ON SUNDAY AFTERNOON OVER THE ADIRONDACKS MOUNTAINS.
OTHERWISE...THE NEXT CHANCE FOR RAIN WILL BE ASSOCIATED WITH A FRONT
TOWARD THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 310 PM EDT FRIDAY...WATER VAPOR SHOWS BUILDING RIDGE ALOFT
ACROSS THE NE CONUS WITH LARGE SCALE SUBSIDENCE DIRECTLY OVER
REGION. HAVE NOTED A SLIGHT INCREASE IN THICKNESS VALUES AND TEMP
PROFILES COMPARED TO LAST NIGHT...BUT TEMPS WILL BE SIMILAR.
EXPECT A STRONG THERMAL INVERSION TO DEVELOP WITH COOLEST READINGS
IN THE DEEPER/PROTECTED VALLEYS...WITH WARMER TEMPS ON THE
MIDSLOPES AND RIDGETOPS. LOWS WILL RANGE FROM NEAR 40F AT
SLK/COLDER VALLEYS OF THE NEK TO LOWER 60S NEAR THE LAKE CHAMPLAIN
SHORELINE. LATEST RAP CONTS TO SHOW A DEVELOPING 975MB JET OF 15
TO 20 KNOTS ACROSS NORTHERN NY TONIGHT...WHICH MAY KEEP ATMOSPHERE
A LITTLE MIXED AND PREVENT WIDESPREAD DENSE FOG. BEST CHC OF FOG
WILL BE CENTRAL/EASTERN VALLEYS OF VT AFT 06Z.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
AS OF 310 PM EDT FRIDAY...VERY QUIET WEATHER EXPECTED AS
MID/UPPER LVL RIDGE CONTINUES ACROSS THE NE CONUS. THIS WILL
RESULT IN MUCH ABOVE NORMAL TEMPS AND MAINLY DRY CONDITIONS. STILL
WATCHING A WEAK INITIAL 5H VORT AND ASSOCIATED RIBBON OF MOISTURE
THAT IMPACTS OUR WESTERN CWA ON SUNDAY AFTN. SYSTEM HAS LIMITED
FORCING AND IS RUNNING INTO A STRONG RIDGE WITH LOTS OF DRY
AIR...SO WILL KEEP VERY ISOLATED CHANCES FOR AN AFTN SHOWER OVER
NORTHERN NY. THINKING IF ANYTHING DEVELOPS...IT WILL OCCUR OVER
THE TRRN...DURING PEAK HEATING OF THE AFTN HOURS. NAM SOUNDINGS
SHOW CAPE AROUND 1500 J/KG AND UNIDIRECTIONAL WIND PROFILES WITH
SPEEDS BETWEEN 20 AND 25 KNOTS FROM 850 TO 500MB ON SUNDAY
AFTN...AS PWS APPROACH 1.75 INCHES. FORCING AND MOISTURE IS
LIMITED...SO NOT EXPECTING MUCH AREAL COVERAGE OR INTENSITY OF
PRECIP.
OTHERWISE...SFC RIDGE AND BUILDING HEIGHTS ALOFT ON SATURDAY AND
PLENTY OF DRY AIR WILL RESULT IN SUNSHINE AND WARM TEMPS. PROGGED
85H TEMPS BTWN 14 AND 16C SUPPORT HIGHS UPPER 70S MTNS TOWNS TO MID
80S WARMER VALLEYS LOCATIONS LIKE BTV/VSF AND MSS. WINDS WILL
GENERALLY BE TERRAIN DRIVEN...EXCEPT SHIFTING TO THE SOUTH BY
EVENING AS SFC HIGH PRES MOVES INTO THE GULF OF MAINE. A RETURN
SOUTHERLY FLOW WILL ADVECT HIGHER DWPTS BACK INTO OUR REGION BY
SUNDAY...WITH SOME INCREASE IN HUMIDITY VALUES LIKELY. TEMPS SAT
NIGHT WILL RANGE FROM THE MID 40S MTNS VALLEYS TO LOWER/MID 60S CPV
AND URBAN AREAS. ON SUNDAY PROGGED 85H TEMPS ARE NEAR 16C SUPPORTING
HIGHS WELL INTO THE 80S MOST LOCATIONS WITH SOUTH WINDS AT 5 TO 15
MPH.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 327 PM EDT FRIDAY...THE LONG TERM PORTION OF THE FORECAST
WILL START OUT WITH A DRY AND WARM DAY FOR LABOR DAY. GFS MODEL
HINTS AT SOME SCATTERED CONVECTION...WHILE THE ECMWF HAS A DRY DAY
FOR LABOR DAY. THUS...HAVE STUCK WITH THE LOW SUPERBLEND POPS FOR
MONDAY AND MONDAY NIGHT AND HAVE A DRY FORECAST.
ECMWF AND GFS MODELS SHOWING SOME DIFFERENCES ON TUESDAY...WITH
THE GFS MODEL AGAIN HINTING AT SOME SCATTERED CONVECTION ON
TUESDAY...WHILE THE ECMWF MODEL HAS IT DRY AND KEEPS ANY
CONVECTION NORTH OF THE REGION IN CANADA ON TUESDAY AND TUESDAY
NIGHT. HAVE GONE A BIT LOWER THAN SUPERBLEND POPS ON TUESDAY AND
JUST HAVE SLIGHT CHANCE POPS (20 PERCENT) FOR SHOWERS AND
THUNDERSTORMS ON TUESDAY AND TUESDAY NIGHT.
ECMWF AND GFS MODELS IN BETTER AGREEMENT ON WEDNESDAY AND
WEDNESDAY NIGHT WITH BRINGING A SLOW MOVING COLD FRONT INTO THE
REGION. THUS...HAVE STAYED WITH SUPERBLEND POPS FOR WEDNESDAY AND
WEDNESDAY NIGHT AND HAVE A CHANCE OF SHOWERS AND THUNDERSTORMS IN
THE FORECAST FOR WEDNESDAY.
ECMWF AND GFS MODELS SUGGESTING A DRIER FORECAST FOR THURSDAY...SO
HAVE LOWERED SUPERBLEND POPS TO JUST SLIGHT CHANCE POPS (20
PERCENT) FOR SHOWERS ON THURSDAY. ECMWF AND GFS MODELS SHOWING
MOISTURE RETURNING INTO THE REGION ON FRIDAY...SO HAVE A CHANCE OF
SHOWERS IN THE FORECAST FOR FRIDAY.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
THROUGH 18Z SATURDAY...MAINLY VFR CONDITIONS EXPECTED THROUGH THE
PERIOD AS A RIDGE OF HIGH PRESSURE AT THE SURFACE AND ALOFT WILL
BE OVER VERMONT AND NORTHERN NEW YORK. SATELLITE LOOP JUST SHOWING
MAINLY CLEAR SKIES OR JUST A FEW HIGH THIN CIRRUS CLOUDS ACROSS
THE REGION AT THIS TIME. EXPECTING SOME AREAS OF DENSE FOG TO
FORM IN THE SHELTERED VALLEYS OF NORTH CENTRAL AND EASTERN AND
NORTHEAST VERMONT MAINLY FROM 05Z SATURDAY UNTIL 14Z SATURDAY.
ALSO EXPECTING SOME AREAS OF DENSE FOG IN THE SHELTERED VALLEYS OF
THE ADIRONDACKS AFTER 06Z SATURDAY UNTIL 12Z SATURDAY.
OUTLOOK 18Z SATURDAY THROUGH WEDNESDAY...
18Z SAT-00Z TUE...MAINLY VFR EXCEPT FOR VLIFR/IFR FG/BR LIKELY AT
KSLK/KMPV 06Z-13Z EACH MORNING.
00Z TUE-00Z THU...MAINLY VFR. CHANCE SHRA/TSRA WITH FRONTAL
PASSAGE.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...TABER
NEAR TERM...TABER
SHORT TERM...TABER
LONG TERM...WGH
AVIATION...WGH
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
309 PM EDT FRI SEP 4 2015
.SYNOPSIS...
A STRONG RIDGE OF HIGH PRESSURE WILL CONTINUE TO PREVAIL
ACROSS THE NORTH COUNTRY THIS WEEKEND. THIS WILL RESULT IN DRY
CONDITIONS WITH WARM DAYS AND COOL NIGHTS. AN ISOLATED SHOWERS IS
POSSIBLE ON SUNDAY AFTERNOON OVER THE ADIRONDACKS MOUNTAINS.
OTHERWISE...THE NEXT CHANCE FOR RAIN WILL BE ASSOCIATED WITH A FRONT
TOWARD THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 310 PM EDT FRIDAY...WATER VAPOR SHOWS BUILDING RIDGE ALOFT
ACROSS THE NE CONUS WITH LARGE SCALE SUBSIDENCE DIRECTLY OVER
REGION. HAVE NOTED A SLIGHT INCREASE IN THICKNESS VALUES AND TEMP
PROFILES COMPARED TO LAST NIGHT...BUT TEMPS WILL BE SIMILAR.
EXPECT A STRONG THERMAL INVERSION TO DEVELOP WITH COOLEST READINGS
IN THE DEEPER/PROTECTED VALLEYS...WITH WARMER TEMPS ON THE
MIDSLOPES AND RIDGETOPS. LOWS WILL RANGE FROM NEAR 40F AT
SLK/COLDER VALLEYS OF THE NEK TO LOWER 60S NEAR THE LAKE CHAMPLAIN
SHORELINE. LATEST RAP CONTS TO SHOW A DEVELOPING 975MB JET OF 15
TO 20 KNOTS ACROSS NORTHERN NY TONIGHT...WHICH MAY KEEP ATMOSPHERE
A LITTLE MIXED AND PREVENT WIDESPREAD DENSE FOG. BEST CHC OF FOG
WILL BE CENTRAL/EASTERN VALLEYS OF VT AFT 06Z.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
AS OF 310 PM EDT FRIDAY...VERY QUIET WEATHER EXPECTED AS
MID/UPPER LVL RIDGE CONTINUES ACROSS THE NE CONUS. THIS WILL
RESULT IN MUCH ABOVE NORMAL TEMPS AND MAINLY DRY CONDITIONS. STILL
WATCHING A WEAK INITIAL 5H VORT AND ASSOCIATED RIBBON OF MOISTURE
THAT IMPACTS OUR WESTERN CWA ON SUNDAY AFTN. SYSTEM HAS LIMITED
FORCING AND IS RUNNING INTO A STRONG RIDGE WITH LOTS OF DRY
AIR...SO WILL KEEP VERY ISOLATED CHANCES FOR AN AFTN SHOWER OVER
NORTHERN NY. THINKING IF ANYTHING DEVELOPS...IT WILL OCCUR OVER
THE TRRN...DURING PEAK HEATING OF THE AFTN HOURS. NAM SOUNDINGS
SHOW CAPE AROUND 1500 J/KG AND UNIDIRECTIONAL WIND PROFILES WITH
SPEEDS BETWEEN 20 AND 25 KNOTS FROM 850 TO 500MB ON SUNDAY
AFTN...AS PWS APPROACH 1.75 INCHES. FORCING AND MOISTURE IS
LIMITED...SO NOT EXPECTING MUCH AREAL COVERAGE OR INTENSITY OF
PRECIP.
OTHERWISE...SFC RIDGE AND BUILDING HEIGHTS ALOFT ON SATURDAY AND
PLENTY OF DRY AIR WILL RESULT IN SUNSHINE AND WARM TEMPS. PROGGED
85H TEMPS BTWN 14 AND 16C SUPPORT HIGHS UPPER 70S MTNS TOWNS TO MID
80S WARMER VALLEYS LOCATIONS LIKE BTV/VSF AND MSS. WINDS WILL
GENERALLY BE TERRAIN DRIVEN...EXCEPT SHIFTING TO THE SOUTH BY
EVENING AS SFC HIGH PRES MOVES INTO THE GULF OF MAINE. A RETURN
SOUTHERLY FLOW WILL ADVECT HIGHER DWPTS BACK INTO OUR REGION BY
SUNDAY...WITH SOME INCREASE IN HUMIDITY VALUES LIKELY. TEMPS SAT
NIGHT WILL RANGE FROM THE MID 40S MTNS VALLEYS TO LOWER/MID 60S CPV
AND URBAN AREAS. ON SUNDAY PROGGED 85H TEMPS ARE NEAR 16C SUPPORTING
HIGHS WELL INTO THE 80S MOST LOCATIONS WITH SOUTH WINDS AT 5 TO 15
MPH.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 255 AM EDT FRIDAY...AS WE FINISH UP THE LONG HOLIDAY
WEEKEND THE AFOREMENTIONED UPPER RIDGE CONTINUES TO BREAK DOWN TO
ZONAL FLOW ACROSS THE NORTHEAST WHILE SURFACE HIGH PRESSURE
REMAINS OVER THE EASTERN SEABOARD. THE RESULTING WEATHER WILL BE
CONTINUED WARM ADD DRY CONDITIONS SUNDAY NIGHT THROUGH MONDAY
NIGHT WITH TEMPERATURES WELL ABOVE NORMAL RUNNING IN THE UPPER 50S
TO MID 60S FOR LOWS, AND MID TO UPPER 80S FOR HIGHS.
FOR TUESDAY, LONG RANGE GUIDANCE STILL SHOWING SOME DIFFERENCES IN
THE DEPTH OF MOISTURE AND STRENGTH OF A PRE-FRONTAL TROUGH PUSHING
THROUGH THE REGION. GFS AND CANADIAN GEM CONTINUE TO HIGHLIGHT A
LITTLE BETTER MOISTURE THAN THE ECMWF WHICH HOLDS ON STRONGER TO THE
RIDGE IN PLACE. IN ALL LIKELIHOOD A SOLUTION SOMEWHERE IN THE MIDDLE
WILL OCCUR WITH A FEW LIGHT SCATTERED SHOWERS, BUT NOT EXPECTING
MUCH OVERALL IMPACT. MEANWHILE, MODELS ARE IN GOOD AGREEMENT MOVING
FORWARD TO THE WEDNESDAY/THURSDAY TIME-FRAME WHERE A MORE POTENT
UPPER TROUGH AND SURFACE COLD FRONT TRACK FROM THE GREAT LAKES
THROUGH THE NORTHEAST. AS THE PREVIOUS FORECASTER MENTIONED THOUGH,
THE BEST DYNAMICS LIFT NORTHEASTWARD WITH THE PARENT SURFACE LOW
WEDNESDAY, BUT THE TRAILING SHORTWAVE TROUGH SHIFTS RIGHT THROUGH
THE BTV CWA THURSDAY LIKELY PRODUCING MORE WIDESPREAD CONVECTIVE
SHOWERS. ONE THING`S FOR SURE, BEHIND THIS FRONT WE WILL SEE A
RETURN TO MORE NORMAL LATE SUMMER TEMPERATURES AND HOPEFULLY
(FINGERS CROSSED) THE END OF THIS HOT/HUMID STRETCH.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
THROUGH 18Z SATURDAY...MAINLY VFR CONDITIONS EXPECTED THROUGH THE
PERIOD AS A RIDGE OF HIGH PRESSURE AT THE SURFACE AND ALOFT WILL
BE OVER VERMONT AND NORTHERN NEW YORK. SATELLITE LOOP JUST SHOWING
MAINLY CLEAR SKIES OR JUST A FEW HIGH THIN CIRRUS CLOUDS ACROSS
THE REGION AT THIS TIME. EXPECTING SOME AREAS OF DENSE FOG TO
FORM IN THE SHELTERED VALLEYS OF NORTH CENTRAL AND EASTERN AND
NORTHEAST VERMONT MAINLY FROM 05Z SATURDAY UNTIL 14Z SATURDAY.
ALSO EXPECTING SOME AREAS OF DENSE FOG IN THE SHELTERED VALLEYS OF
THE ADIRONDACKS AFTER 06Z SATURDAY UNTIL 12Z SATURDAY.
OUTLOOK 18Z SATURDAY THROUGH WEDNESDAY...
18Z SAT-00Z TUE...MAINLY VFR EXCEPT FOR VLIFR/IFR FG/BR LIKELY AT
KSLK/KMPV 06Z-13Z EACH MORNING.
00Z TUE-00Z THU...MAINLY VFR. CHANCE SHRA/TSRA WITH FRONTAL
PASSAGE.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...TABER
NEAR TERM...TABER
SHORT TERM...TABER
LONG TERM...LAHIFF
AVIATION...WGH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
127 AM EDT FRI SEP 4 2015
.SYNOPSIS...AN UPPER LEVEL DISTURBANCE WILL AMPLIFY ACROSS CENTRAL
TODAY. MEANWHILE AT THE SURFACE...A BACKDOOR COLD FRONT WILL
APPROACH FROM THE NORTH LATE TODAY...THEN PUSH SOUTHWARD THROUGH THE
AREA TONIGHT...BEFORE SETTLING TO OUR SOUTH ON SATURDAY. HIGH
PRESSURE WILL EXTEND INTO THE REGION FROM THE NORTH OVER THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1050 PM THURSDAY...
EVENING WATER VAPOR IMAGERY DEPICTED AN ELONGATED AXIS OF SHEAR
VORTICITY STRETCHING FROM WESTERN NC NORTHWESTWARD TO A WELL-DEFINED
SHORTWAVE TROUGH OVER WISCONSIN. NWP GUIDANCE INDICATES THE
VORTICITY AXIS WILL BECOME MORE CONCENTRIC WITH TIME AND
SOUTHEASTWARD EXTENT/NEAR THE BASE OF THE PARENT TROUGH AXIS OVER
THE CAROLINAS...ULTIMATELY CULMINATING IN A CLOSED UPPER LOW AND
POCKET OF -9 TO -10 C 500 MB TEMPERATURES OVER CENTRAL NC DURING THE
DAY FRI. THE PRECEDING ASSOCIATED DYNAMIC FORCING FOR ASCENT IS
FORECAST TO SPREAD EAST OF THE APPALACHIANS AND ACROSS CENTRAL VA
AND CENTRAL NC BETWEEN 06-12Z. SHOWERS HAVE BEEN PERCOLATING OVER
WESTERN NC DURING THE PAST COUPLE OF HOURS (AFTER SUNSET/DURING A
TIME THAT SOLELY-DIURNALLY-DRIVEN CONVECTION SHOULD BE DIMINISHING);
AND THIS ACTIVITY IS PRESUMABLY INDICATIVE OF THE INFLUENCE OF THE
AMPLIFYING VORT MAX. THAT FORCING...IN CONJUNCTION WITH LOW LEVEL
CONVERGENCE ALONG A LEE SURFACE TROUGH THAT NEARLY PERFECTLY BISECTS
THE RAH CWFA FROM NNE TO SSW THIS EVENING...MAY YET FOCUS SOME
ISOLATED SHOWERS OVERNIGHT...MAINLY ALONG AND EAST OF THE TROUGH
AXIS/WHERE LOW LEVEL MOISTURE AND ASSOCIATED INSTABILITY FIELDS
ARE/WILL CONTINUE TO BE RELATIVELY MAXIMIZED.
OTHERWISE...SURFACE VISIBILITY IS ALREADY DECREASING ACROSS CENTRAL
NC...AND BOTH STATISTICAL GUIDANCE AND HRRR VISIBILITY FORECASTS
SUGGEST VISIBILITY RESTRICTIONS WILL CONTINUE TO EXPAND AND LOWER IN
A RELATIVELY CALM...CLEAR...AND MOIST (IN THE BOUNDARY LAYER)
ENVIRONMENT OVER CENTRAL NC OVERNIGHT. LOWS AGAIN IN THE UPPER 60S
TO LOWER 70S.
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 325 PM THURSDAY...
OUR BEST SHOT AT SCATTERED TO NUMEROUS SHOWERS AND STORMS WILL BE
LATE FRI INTO FRI NIGHT... WITH SEVERAL FAVORABLE FACTORS IN PLAY.
FIRST... MODELS DEPICT A POCKET OF ABOVE-NORMAL PW SLIDING SOUTHWARD
FROM VA INTO/THROUGH CENTRAL NC TOMORROW... IN CONJUNCTION WITH WEAK
DPVA SPREADING IN FROM THE NW AND NE AND IMPROVING UPPER DIVERGENCE
FROM THE NORTH... ALL AHEAD OF THE INCOMING BACKDOOR COLD FRONT. THE
LARGE-SCALE MODELS INCLUDING THE NAM/GFS/ECMWF/SREF ARE IN AGREEMENT
ON CONVECTION DEVELOPING DURING THE EARLY TO MID AFTERNOON OVER
CENTRAL NC... FOCUSING THE BEST COVERAGE AND HIGHEST AMOUNTS OVER
THE FAR NW PIEDMONT. GIVEN THE EXPECTED MID-UPPER LEVEL DYNAMIC
CONTRIBUTIONS TO ASCENT... DESTABILIZATION WITH GOOD HEATING DURING
THE DAY... AND RISING MOISTURE THROUGH THE COLUMN... CONVECTIVE
COVERAGE LOOKS SUFFICIENT TO RAISE POPS A BIT... TO LIKELY IN THE NW
CWA WITH GOOD CHANCES ELSEWHERE FOR NOW (ALTHOUGH THESE MAY GO UP TO
LIKELY HERE AS WELL IN LATER FORECASTS IF TRENDS HOLD). THE WEAK
DEEP LAYER SHEAR SHOULD LIMIT STORM STRENGTH... ALTHOUGH THE PROFILE
AND DCAPE NOTED ON NAM FORECAST SOUNDINGS WOULD SUGGEST A MARGINAL
WIND THREAT. THE ANTICIPATED SLOW MOVEMENT WITH HIGH WATER CONTENT
WILL BRING A RISK OF SLOW-MOVING STORMS GENERATING URBAN FLOODING.
EXPECT HIGHS OF 90-95 WITH DECENT PREFRONTAL HEATING AND CONTINUED
ABOVE NORMAL THICKNESSES. POPS SHOULD TREND DOWNWARD AFTER NIGHTFALL
WITH LOSS OF INSOLATION... HOWEVER WITH LOW LEVEL CONFLUENT FLOW
NEAR THE BACKDOOR FRONT AND INCREASED ATLANTIC-SOURCE FEED WITH
PERSISTENT UPPER DIVERGENCE OVERNIGHT... WILL KEEP A MENTION OF
SCATTERED SHOWERS AND STORMS THROUGH THE NIGHT... WITH THE BEST
CHANCES WEST. LOWS 67-71. -GIH
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
AS OF 150 PM THURSDAY...
COOLER TEMPERATURES EXPECTED FOR MUCH OF THE LONG TERM AS THE COLD
FRONT THAT IS PROGGED TO COME THROUGH FRIDAY NIGHT WILL BRING A
CHANGE IN AIRMASS FROM THE NORTHEAST. WITH THIS WILL COME A GREATER
FETCH OF MOISTURE FROM OFFSHORE...DRIVEN BY SEVERAL SHORTWAVE
IMPULSES THAT ARE EXPECTED TO MOVE INTO THE STATE DURING THE WEEKEND
AND INTO EARLY NEXT WEEK.
FOR THE WEEKEND...THE GREATEST THREAT FOR RAIN WILL BE IN THE WEST
ON SATURDAY AS THE FRONT MOVES THROUGH AND A CAD-LIKE SCENARIO SETS
UP. AS THE WEEKEND PROGRESSES HOWEVER...AN INVERTED TROUGH ALONG THE
EAST COAST WILL SHARPEN AND THUS BRING A MORE NORTHERLY COMPONENT TO
THE WIND AND SHUT OFFSHORE MOISTURE FEED INTO THE NW PIEDMONT AND
INSTEAD BEGIN TO FOCUS THE BEST CHANCE FOR CONVECTION OVER THE
EASTERN PART OF THE STATE. THUS RAIN CHANCES FOR SUNDAY WILL BE
BETTER IN THE EAST THAN IN THE WEST. THIS PATTERN WILL CONTINUE INTO
LABOR DAY WITH SOUTHEASTERN COUNTIES HAVING THE BEST CHANCE FOR
SHOWERS AND THUNDERSTORMS. HIGHS IN THE LOW TO MID 80S FOR THIS
PERIOD WITH THE POTENTIAL FOR SOME UPPER 70S IN THE NW IF CLOUD
COVER LOCKS IN.
THE BERMUDA HIGH BEGINS TO TAKE BACK OVER FOR MIDWEEK AND THE
SURFACE HIGH OVER OUR AREA AND THE INVERTED TROUGH WILL BEGIN TO
BREAK DOWN. THIS WILL SEE A RETURN TO WARMER TEMPERATURES...ALTHOUGH
GRADUALLY...WITH DIURNAL CHANCES FOR SHOWERS AND ISOLATED
THUNDERSTORMS THROUGH THURSDAY. AT THIS TIME...ANY THUNDERSTORMS
THAT DO OCCUR EITHER THIS WEEKEND OR NEXT WEEK ARE NOT EXPECTED TO
BE SEVERE...BUT A FEW STRONG STORMS CANNOT BE RULED OUT.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 120 AM FRIDAY...
24 HR TAF PERIOD: EARLY MORNING FOG AND LOW STRATUS DEVELOPMENT IS
UNDERWAY ACROSS CENTRAL NC... WITH LOCATIONS AGAIN ACROSS THE
NORTHEAST PIEDMONT AND NORTHERN AND CENTRAL COASTAL EXPECTED TO SEE
THE MOST COVERAGE AND IFR/LIFR CONDITIONS... THANKS IN PART TO MOIST
SOILS FROM THE CONVECTION LATE WEDNESDAY AND EARLY THURSDAY MORNING.
THUS... AGAIN THINK IFR/LIFR FOG AND LOW STRATUS WILL DEVELOP AT
KRWI AND KRDU THIS MORNING... WITH GENERALLY MVFR VISBYS AT
KFAY/KGSO/KINT. ANY FOG AND STRATUS THAT DEVELOPS EARLY THIS MORNING
SHOULD LIFT WITHIN A FEW HOURS OF SUNRISE AGAIN... WITH SKIES
BECOMING MOSTLY TO PARTLY SUNNY BY MID MORNING. HOWEVER... AS A
MID/UPPER LEVEL DISTURBANCE CONTINUES TO MOVE INTO THE REGION
COUPLED WITH THE APPROACH OF A BACKDOOR COLD FRONT... EXPECT CLOUD
COVER SHOULD THICKEN THIS AFTERNOON INTO THE EVENING... WITH
SCATTERED TO POTENTIALLY NUMEROUS SHOWERS AND STORMS DEVELOPING.
THUS... HAVE ADDED A PROB30 GROUP FOR THE POTENTIAL FOR CONVECTION
THIS AFTERNOON AND EVENING AT ALL TAF SITES. ANY STORMS THAT DEVELOP
WILL HAVE THE POTENTIAL TO PRODUCE AT LEAST IFR CONDITIONS IN HEAVY
RAIN... ALONG WITH GUSTY WINDS.
OUTLOOK: LINGERING SHOWERS AND EVEN SOME ISOLATED STORMS MAY
CONTINUE INTO THE EARLY MORNING HOURS OF SATURDAY... AS THE FRONT
MOVES THROUGH THE AREA... WITH LOCATIONS ACROSS THE WESTERN PIEDMONT
STANDING THE BEST CHANCE AS SEEING LINGERING CONVECTION (KGSO/KINT).
MORE WIDELY SCATTERED CONVECTION IS POSSIBLE DURING THE AFTERNOON
AND EVENING ON SATURDAY AND SUNDAY WITH A DECREASE IN COVERAGE AND A
FOCUS TOWARD THE COASTAL PLAIN ON MONDAY AND TUESDAY. LATE NIGHT AND
MORNING FOG AND STRATUS WITH POTENTIALLY SIGNIFICANT RESTRICTIONS
APPEAR PROBABLE ON SATURDAY AND SUNDAY MORNINGS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BSD/26
NEAR TERM...26
SHORT TERM...HARTFIELD
LONG TERM...ELLIS
AVIATION...BSD/BLAES
AREA FORECAST DISCUSSION
NWS BISMARCK ND
952 PM CDT SAT SEP 5 2015
.UPDATE...
ISSUED AT 946 PM CDT SAT SEP 5 2015
THUNDERSTORMS CONTINUE TO INCREASE IN COVERAGE AND INTENSITY OVER
SOUTHEAST MONTANA DURING THE PAST HOUR. STRONG FORCING ASSOCIATED
WITH A SHORTWAVE LIFTING THROUGH CENTRAL MONTANA WITH A STILL
UNSTABLE AIRMASS OVER FAR SOUTHEAST MONTANA INTO SOUTHWEST NORTH
DAKOTA. BOTH HAIL AND WIND REPORTS FROM CONVECTION OVER SOUTHEAST
MONTANA. THINK THE MAIN THREAT FOR STRONG TO SEVERE THUNDERSTORMS
WILL BE OVER SOUTHWEST NORTH DAKOTA MAINLY ALONG AND SOUTH OF THE
INTERSTATE. ATMOSPHERE BECOMES MORE STABLE AS YOU MOVE NORTH OF
THE INTERSTATE. STILL EXPECT SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS EXTENDING INTO NORTHWEST AND EVENTUALLY THE NORTH
CENTRAL LATE TONIGHT. ALSO UNCERTAIN ABOUT INSTABILITY AS YOU
MOVE FROM THE SOUTHWEST INTO THE SOUTH CENTRAL BUT WITH WATCH IN
EFFECT EAST TO THE MISSOURI...WILL KEEP THE MENTION OF SEVERE HERE
AS WELL. UPDATED POPS BASED ON LATEST RADAR ANALYSIS WITH HRRR AND
EXP-HRRR FOR INPUT THROUGH AROUND 08 UTC.
UPDATE ISSUED AT 734 PM CDT SAT SEP 5 2015
UPDATE TO CLEAN UP POPS OVER EASTERN NORTH DAKOTA THIS EVENING.
LOOKS LIKE SHOWER AND ISOLATED THUNDERSTORM ACTIVITY SHOULD BE
MOVING OUT OF EASTERN PORTIONS OF CENTRAL NORTH DAKOTA IN A COUPLE
OF HOURS...THEN DRY SLOTTED UNTIL POSSIBLE SHOWERS MOVE INTO THE
AREA TOWARD MORNING.
UPDATE ISSUED AT 703 PM CDT SAT SEP 5 2015
SPC HAS ISSUED A SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
SOUTHWEST AND SOUTH CENTRAL NORTH DAKOTA...MAINLY SOUTH AND WEST
OF LAKE SAKAKAWEA AND THE MISSOURI RIVER. VERY MOIST AND UNSTABLE
ATMOSPHERE REMAINS ACROSS SOUTHWEST NORTH DAKOTA. TO THE WEST
CONVECTION HAS FIRED OFF THE BIGHORNS ALONG A BOUNDARY THAT
EXTENDS INTO FAR NORTHWEST SOUTH DAKOTA. ALSO...STRONG COLD FRONT
WILL BE PUSHING SOUTHEAST THROUGH EASTERN MONTANA THIS EVENING.
LATEST MESOSCALE MODELS HAVE NOT BEEN AS ROBUST AS EARLIER THIS
AFTERNOON...BUT IF WE DO GET CONVECTION FIRING OVER SOUTHEAST
MONTANA OR NORTHWEST SOUTH DAKOTA...IT WOULD LIKELY TRACK INTO
SOUTHWEST NORTH DAKOTA...WHERE MUCAPES REMAIN ABOVE 2000J/KG AND
0-6KM BULK SHEAR AROUND 50 KNOTS ADVECTS INTO THE AREA.
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 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 946 PM CDT SAT SEP 5 2015
IFR STRATUS AND PATCHY FOG HAS DISSIPATED MOST AREAS BUT IS
EXPECTED TO RETURN LATER TONIGHT INTO SUNDAY MORNING. SCATTERED
TO NUMEROUS SHOWERS AND THUNDERSTORMS HAVE MOVED INTO THE EASTERN
DAKOTAS...WITH ANOTHER ROUND ENTERING WESTERN NORTH DAKOTA LATER
TONIGHT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
737 PM CDT SAT SEP 5 2015
.UPDATE...
ISSUED AT 734 PM CDT SAT SEP 5 2015
UPDATE TO CLEAN UP POPS OVER EASTERN NORTH DAKOTA THIS EVENING.
LOOKS LIKE SHOWER AND ISOLATED THUNDERSTORM ACTIVITY SHOULD BE
MOVING OUT OF EASTERN PORTIONS OF CENTRAL NORTH DAKOTA IN A COUPLE
OF HOURS...THEN DRY SLOTTED UNTIL POSSIBLE SHOWERS MOVE INTO THE
AREA TOWARD MORNING.
UPDATE ISSUED AT 703 PM CDT SAT SEP 5 2015
SPC HAS ISSUED A SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
SOUTHWEST AND SOUTH CENTRAL NORTH DAKOTA...MAINLY SOUTH AND WEST
OF LAKE SAKAKAWEA AND THE MISSOURI RIVER. VERY MOIST AND UNSTABLE
ATMOSPHERE REMAINS ACROSS SOUTHWEST NORTH DAKOTA. TO THE WEST
CONVECTION HAS FIRED OFF THE BIGHORNS ALONG A BOUNDARY THAT
EXTENDS INTO FAR NORTHWEST SOUTH DAKOTA. ALSO...STRONG COLD FRONT
WILL BE PUSHING SOUTHEAST THROUGH EASTERN MONTANA THIS EVENING.
LATEST MESOSCALE MODELS HAVE NOT BEEN AS ROBUST AS EARLIER THIS
AFTERNOON...BUT IF WE DO GET CONVECTION FIRING OVER SOUTHEAST
MONTANA OR NORTHWEST SOUTH DAKOTA...IT WOULD LIKELY TRACK INTO
SOUTHWEST NORTH DAKOTA...WHERE MUCAPES REMAIN ABOVE 2000J/KG AND
0-6KM BULK SHEAR AROUND 50 KNOTS ADVECTS INTO THE AREA.
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 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 734 PM CDT SAT SEP 5 2015
IFR STRATUS AND PATCHY FOG HAS DISSIPATED MOST AREAS BUT IS
EXPECTED TO RETURN LATER TONIGHT INTO SUNDAY MORNING. SCATTERED
TO NUMEROUS SHOWERS AND THUNDERSTORMS HAVE MOVED INTO THE EASTERN
DAKOTAS...WITH ANOTHER ROUND ENTERING WESTERN NORTH DAKOTA LATER
TONIGHT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
713 PM CDT SAT SEP 5 2015
.UPDATE...
ISSUED AT 703 PM CDT SAT SEP 5 2015
SPC HAS ISSUED A SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
SOUTHWEST AND SOUTH CENTRAL NORTH DAKOTA...MAINLY SOUTH AND WEST
OF LAKE SAKAKAWEA AND THE MISSOURI RIVER. VERY MOIST AND UNSTABLE
ATMOSPHERE REMAINS ACROSS SOUTHWEST NORTH DAKOTA. TO THE WEST
CONVECTION HAS FIRED OFF THE BIGHORNS ALONG A BOUNDARY THAT
EXTENDS INTO FAR NORTHWEST SOUTH DAKOTA. ALSO...STRONG COLD FRONT
WILL BE PUSHING SOUTHEAST THROUGH EASTERN MONTANA THIS EVENING.
LATEST MESOSCALE MODELS HAVE NOT BEEN AS ROBUST AS EARLIER THIS
AFTERNOON...BUT IF WE DO GET CONVECTION FIRING OVER SOUTHEAST
MONTANA OR NORTHWEST SOUTH DAKOTA...IT WOULD LIKELY TRACK INTO
SOUTHWEST NORTH DAKOTA...WHERE MUCAPES REMAIN ABOVE 2000J/KG AND
0-6KM BULK SHEAR AROUND 50 KNOTS ADVECTS INTO THE AREA.
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 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 703 PM CDT SAT SEP 5 2015
IFR STRATUS AND PATCHY FOG HAS DISSIPATED MOST AREAS BUT IS
EXPECTED TO RETURN LATER TONIGHT INTO SUNDAY MORNING. SCATTERED
TO NUMEROUS SHOWERS AND THUNDERSTORMS HAVE MOVED INTO THE EASTERN
DAKOTAS...WITH ANOTHER ROUND ENTERING WESTERN NORTH DAKOTA LATER
TONIGHT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1207 PM CDT FRI SEP 4 2015
.UPDATE...
ISSUED AT 1202 PM CDT FRI SEP 4 2015
AS OF 17 UTC...THE STRONGEST CONVECTION WAS FOCUSING ACROSS THE
DEVILS LAKE BASIN AND INTO THE NORTHERN RED RIVER VALLEY AHEAD OF
THE SHORTWAVE OVER THE SOUTHERN JAMES RIVER VALLEY. AS THIS WAVE
CONTINUES TO PROPAGATE NORTHEAST...EXPECT A DOWNWARD TREND IN
PRECIPITATION COVERAGE THROUGH THE AFTERNOON.
UPDATE ISSUED AT 902 AM CDT FRI SEP 4 2015
UPDATE TO BLEND OBSERVED RADAR TRENDS TO A TIME LAGGED ENSEMBLE OF
THE 10-12 UTC HRRR ITERATIONS WHICH HAVE A GOOD HANDLE OF ONGOING
CONVECTION THIS MORNING. SPC HAS MAINTAINED THE MARGINAL RISK FOR
SEVERE STORMS FOR THE TURTLE MOUNTAINS THROUGH THE JAMES RIVER
VALLEY AND POINTS EAST THIS AFTERNOON. THE 13 UTC RAP FORECAST
DEPICTS 1500-2000 J/KG OF ML CAPE AND 20-25 KTS OF DEEP LAYER
SHEAR THIS AFTERNOON ACROSS THE AFOREMENTIONED AREAS...SUPPORTING
THE MARGINAL RISK FOR POSSIBLY A SEVERE STORM OR TWO.
HOWEVER...THE RAP ALSO PROPAGATES THE MAIN FORCING MECHANISM OF
THE SHORTWAVE ACROSS CENTRAL SOUTH DAKOTA THIS MORNING INTO
NORTHEAST NORTH DAKOTA LATE THIS AFTERNOON. THUS...THE TIMING OF
THE WAVE SUGGESTS THE BEST POTENTIAL FOR STRONG TO SEVERE STORMS MAY
RESIDE NORTHEAST OF THE CWA.
UPDATE ISSUED AT 628 AM CDT FRI SEP 4 2015
SHOWERS CONTINUE TO LIFT SOUTH TO NORTH OVER THE AREA THIS
MORNING...WITH THE GREATEST COVERAGE AT THIS TIME OVER FAR
WESTERN NORTH DAKOTA. ANOTHER AREA CONTINUES TO DEVELOP OVER
PORTIONS OF SOUTH CENTRAL NORTH DAKOTA...WHILE A BROAD AREA OVER
CENTRAL SOUTH DAKOTA CONTINUES TO LIFT TOWARDS OUR REGION. FOR THE
MORNING UPDATE...HAVE TRIED TO TIME OUT THE MOTION/ARRIVAL OF
THESE STORMS BASED ON CURRENT TRENDS AND LATEST HRRR GUIDANCE AND
HAVE ADJUSTED POPS ACCORDINGLY. UPDATES HAVE BEEN SENT.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 423 AM CDT FRI SEP 4 2015
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE CHANCES FOR
SHOWERS AND THUNDERSTORMS THROUGH THE PERIOD. HEAVY RAIN POTENTIAL
FAR NORTHWEST THIS MORNING AND POSSIBLY ACROSS THE JAMES RIVER
VALLEY.
CURRENTLY...SOUTH-SOUTHWEST FLOW ALOFT. STRONG EMBEDDED S/WV
IMPULSE LIFTING ACROSS WESTERN SOUTH DAKOTA TOWARDS CENTRAL NORTH
DAKOTA RESULTING IN AN INCREASE IN COVERAGE AND INTENSITY IN
SHOWERS AND THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS THE
PAST FEW HOURS. THE MOST FAVORED AREAS WILL BE ALONG A QUASI-
STATIONARY FRONTAL BOUNDARY DRAPED FROM SOUTHWESTERN NORTH DAKOTA
NORTHEAST THROUGH THE TURTLE MOUNTAINS...AND ACROSS MY NORTHWEST
NEAR A POST FRONTAL AXIS. ANOMALOUS MOISTURE SURGING INTO THE
NORTHERN PLAINS WITH LATEST WATER VAPOR LOOP INDICATING A WELL
DEFINED MID/UPPER LEVEL MOISTURE FEED FROM TROPICAL STORM FRED
SOUTHWEST OF BAJA CALIFORNIA. WARM MID-ATMOSPHERIC PROFILE
SUGGESTS A MORE LOCALIZED HEAVY RAIN THREAT VERSUS WIDESPREAD.
WILL CONTINUE TO MONITOR.
AS MENTIONED ABOVE...AND AS HIGH RES AND LATEST NAM MODEL
SUGGEST...NORTHWESTERN NORTH DAKOTA AND THE JAMES RIVER VALLEY
LOOK HAVE THE GREATEST POTENTIAL AT THIS TIME FOR HEAVY RAINFALL.
VIGOROUS CONVECTION OVER SOUTHEASTERN SASKATCHEWAN SHOWING SOME
SIGNS OF DEVELOPING SOUTH INTO MY NORTHWEST. CONVECTIVE COMPLEX
OVER CENTRAL SOUTH DAKOTA MOVING NORTH WHICH LATEST NAM AND HRRR
BRING INTO THE JAMES RIVER BASIN 12-15Z OR SO. VERY UNSEASONABLE
HIGH DEWPOINT TEMPERATURES OUT THERE IN THE 60S TO LOW 70S
CENTRAL AND EAST.
EMBEDDED WAVE CONTINUES TO LIFT NORTH-NORTHEAST TODAY AND EXPECT
CLEARING SKIES AND DECREASING CHANCES FOR SHOWERS/THUNDERSTORMS
FROM SOUTH TO NORTH IN THE WAVE`S WAKE THIS AFTERNOON. LATEST SPC
OUTLOOK MOVED THE SLIGHT RISK AREA INTO MAINLY THE RED RIVER
VALLEY OF EASTERN NORTH DAKOTA...SO OPTED TO REMOVE SEVERE WORDING
IN OUR PRODUCTS. MODELS HINTING AT LOW LEVEL STRATUS/FOG DEVELOPING
TONIGHT WITH LOW LEVEL MOISTURE REMAINING HIGH COUPLED WITH
FORECAST RAINFALL TODAY.
NEXT STRONG EMBEDDED WAVE LIFTS NORTH-NORTHEAST LATE TONIGHT INTO
SATURDAY...WITH INCREASING POPS WEST LATE TONIGHT THEN SPREADING
EAST AND NORTH ACROSS THE REMAINDER OF THE STATE DURING THE DAY
SATURDAY.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 359 AM CDT FRI SEP 4 2015
UPPER LEVEL TROUGH CLOSES OFF TOWARDS NORTHERN MONTANA THROUGH THE
NIGHT ON SATURDAY WITH PRECIPITATION CHANCES SLOWLY TAPERING OFF
THROUGH THE NIGHT FROM SOUTH TO NORTH. ON SUNDAY...GREATEST
CHANCES WILL BE RESTRICTED TO NORTHERN PORTIONS OF THE AREA AS
UPPER LOW STARTS TO WORK ITS WAY TOWARDS THE EAST/NORTHEAST ACROSS
THE SOUTHERN PRAIRIE PROVINCES. DRY CONDITIONS EXPECTED OVER MOST
LOCATIONS BY SUNDAY NIGHT. BREEZY/WINDY CONDITIONS EXPECTED ON
SUNDAY AS SYSTEM BECOMES STACKED.
MAINLY DRY CONDITIONS EXPECTED ON MONDAY WITH COOLING TREND
CONTINUING AS LOW CONTINUES ITS TRACK NORTH OF THE AREA. THIS WILL
BRING CONTINUED BREEZY CONDITIONS OVER NORTHERN LOCATIONS. MAINLY
DRY CONDITIONS EXPECTED THROUGH MID-WEEK WITH A GRADUAL WARMING
TREND EXPECTED AS RIDGE BUILDS OVER WESTERN CONUS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1202 PM CDT FRI SEP 4 2015
WIDESPREAD MVFR/IFR STRATUS ACROSS WESTERN AND CENTRAL NORTH
DAKOTA WILL SLOWLY LIFT AND ERRODE INTO THE AFTERNOON.
THUNDERSTORMS ARE EXPECTED TO IMPACT KJMS THROUGH 19-20 UTC. FOG
AND STRATUS MAY BUILD ACROSS MUCH OF THE AREA AGAIN TONIGHT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...NH
LONG TERM...JJS
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
913 AM CDT FRI SEP 4 2015
.UPDATE...
ISSUED AT 902 AM CDT FRI SEP 4 2015
UPDATE TO BLEND OBSERVED RADAR TRENDS TO A TIME LAGGED ENSEMBLE OF
THE 10-12 UTC HRRR ITERATIONS WHICH HAVE A GOOD HANDLE OF ONGOING
CONVECTION THIS MORNING. SPC HAS MAINTAINED THE MARGINAL RISK FOR
SEVERE STORMS FOR THE TURTLE MOUNTAINS THROUGH THE JAMES RIVER
VALLEY AND POINTS EAST THIS AFTERNOON. THE 13 UTC RAP FORECAST
DEPICTS 1500-2000 J/KG OF ML CAPE AND 20-25 KTS OF DEEP LAYER
SHEAR THIS AFTERNOON ACROSS THE AFOREMENTIONED AREAS...SUPPORTING
THE MARGINAL RISK FOR POSSIBLY A SEVERE STORM OR TWO.
HOWEVER...THE RAP ALSO PROPAGATES THE MAIN FORCING MECHANISM OF
THE SHORTWAVE ACROSS CENTRAL SOUTH DAKOTA THIS MORNING INTO
NORTHEAST NORTH DAKOTA LATE THIS AFTERNOON. THUS...THE TIMING OF
THE WAVE SUGGESTS THE BEST POTENTIAL FOR STRONG TO SEVERE STORMS MAY
RESIDE NORTHEAST OF THE CWA.
UPDATE ISSUED AT 628 AM CDT FRI SEP 4 2015
SHOWERS CONTINUE TO LIFT SOUTH TO NORTH OVER THE AREA THIS
MORNING...WITH THE GREATEST COVERAGE AT THIS TIME OVER FAR
WESTERN NORTH DAKOTA. ANOTHER AREA CONTINUES TO DEVELOP OVER
PORTIONS OF SOUTH CENTRAL NORTH DAKOTA...WHILE A BROAD AREA OVER
CENTRAL SOUTH DAKOTA CONTINUES TO LIFT TOWARDS OUR REGION. FOR THE
MORNING UPDATE...HAVE TRIED TO TIME OUT THE MOTION/ARRIVAL OF
THESE STORMS BASED ON CURRENT TRENDS AND LATEST HRRR GUIDANCE AND
HAVE ADJUSTED POPS ACCORDINGLY. UPDATES HAVE BEEN SENT.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 423 AM CDT FRI SEP 4 2015
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE CHANCES FOR
SHOWERS AND THUNDERSTORMS THROUGH THE PERIOD. HEAVY RAIN POTENTIAL
FAR NORTHWEST THIS MORNING AND POSSIBLY ACROSS THE JAMES RIVER
VALLEY.
CURRENTLY...SOUTH-SOUTHWEST FLOW ALOFT. STRONG EMBEDDED S/WV
IMPULSE LIFTING ACROSS WESTERN SOUTH DAKOTA TOWARDS CENTRAL NORTH
DAKOTA RESULTING IN AN INCREASE IN COVERAGE AND INTENSITY IN
SHOWERS AND THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS THE
PAST FEW HOURS. THE MOST FAVORED AREAS WILL BE ALONG A QUASI-
STATIONARY FRONTAL BOUNDARY DRAPED FROM SOUTHWESTERN NORTH DAKOTA
NORTHEAST THROUGH THE TURTLE MOUNTAINS...AND ACROSS MY NORTHWEST
NEAR A POST FRONTAL AXIS. ANOMALOUS MOISTURE SURGING INTO THE
NORTHERN PLAINS WITH LATEST WATER VAPOR LOOP INDICATING A WELL
DEFINED MID/UPPER LEVEL MOISTURE FEED FROM TROPICAL STORM FRED
SOUTHWEST OF BAJA CALIFORNIA. WARM MID-ATMOSPHERIC PROFILE
SUGGESTS A MORE LOCALIZED HEAVY RAIN THREAT VERSUS WIDESPREAD.
WILL CONTINUE TO MONITOR.
AS MENTIONED ABOVE...AND AS HIGH RES AND LATEST NAM MODEL
SUGGEST...NORTHWESTERN NORTH DAKOTA AND THE JAMES RIVER VALLEY
LOOK HAVE THE GREATEST POTENTIAL AT THIS TIME FOR HEAVY RAINFALL.
VIGOROUS CONVECTION OVER SOUTHEASTERN SASKATCHEWAN SHOWING SOME
SIGNS OF DEVELOPING SOUTH INTO MY NORTHWEST. CONVECTIVE COMPLEX
OVER CENTRAL SOUTH DAKOTA MOVING NORTH WHICH LATEST NAM AND HRRR
BRING INTO THE JAMES RIVER BASIN 12-15Z OR SO. VERY UNSEASONABLE
HIGH DEWPOINT TEMPERATURES OUT THERE IN THE 60S TO LOW 70S
CENTRAL AND EAST.
EMBEDDED WAVE CONTINUES TO LIFT NORTH-NORTHEAST TODAY AND EXPECT
CLEARING SKIES AND DECREASING CHANCES FOR SHOWERS/THUNDERSTORMS
FROM SOUTH TO NORTH IN THE WAVE`S WAKE THIS AFTERNOON. LATEST SPC
OUTLOOK MOVED THE SLIGHT RISK AREA INTO MAINLY THE RED RIVER
VALLEY OF EASTERN NORTH DAKOTA...SO OPTED TO REMOVE SEVERE WORDING
IN OUR PRODUCTS. MODELS HINTING AT LOW LEVEL STRATUS/FOG DEVELOPING
TONIGHT WITH LOW LEVEL MOISTURE REMAINING HIGH COUPLED WITH
FORECAST RAINFALL TODAY.
NEXT STRONG EMBEDDED WAVE LIFTS NORTH-NORTHEAST LATE TONIGHT INTO
SATURDAY...WITH INCREASING POPS WEST LATE TONIGHT THEN SPREADING
EAST AND NORTH ACROSS THE REMAINDER OF THE STATE DURING THE DAY
SATURDAY.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 359 AM CDT FRI SEP 4 2015
UPPER LEVEL TROUGH CLOSES OFF TOWARDS NORTHERN MONTANA THROUGH THE
NIGHT ON SATURDAY WITH PRECIPITATION CHANCES SLOWLY TAPERING OFF
THROUGH THE NIGHT FROM SOUTH TO NORTH. ON SUNDAY...GREATEST
CHANCES WILL BE RESTRICTED TO NORTHERN PORTIONS OF THE AREA AS
UPPER LOW STARTS TO WORK ITS WAY TOWARDS THE EAST/NORTHEAST ACROSS
THE SOUTHERN PRAIRIE PROVINCES. DRY CONDITIONS EXPECTED OVER MOST
LOCATIONS BY SUNDAY NIGHT. BREEZY/WINDY CONDITIONS EXPECTED ON
SUNDAY AS SYSTEM BECOMES STACKED.
MAINLY DRY CONDITIONS EXPECTED ON MONDAY WITH COOLING TREND
CONTINUING AS LOW CONTINUES ITS TRACK NORTH OF THE AREA. THIS WILL
BRING CONTINUED BREEZY CONDITIONS OVER NORTHERN LOCATIONS. MAINLY
DRY CONDITIONS EXPECTED THROUGH MID-WEEK WITH A GRADUAL WARMING
TREND EXPECTED AS RIDGE BUILDS OVER WESTERN CONUS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 902 AM CDT FRI SEP 4 2015
PATCHY FOG AND IFR STRATUS POTENTIAL THROUGH MID MORNING WITH
VERY HIGH BOUNDARY LAYER MOISTURE ACROSS THE REGION. WESTERN
TERMINALS WILL SEE -SHRA AND VCTS NOW THROUGH MID
MORNING...SPREADING EAST MID MORNING THROUGH THE AFTERNOON. AT
LEAST PARTIAL CLEARING EXPECTED FROM SOUTH TO NORTH TODAY INTO
THIS EVENING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...NH
LONG TERM...JJS
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
633 AM CDT FRI SEP 4 2015
.UPDATE...
ISSUED AT 628 AM CDT FRI SEP 4 2015
SHOWERS CONTINUE TO LIFT SOUTH TO NORTH OVER THE AREA THIS
MORNING...WITH THE GREATEST COVERAGE AT THIS TIME OVER FAR
WESTERN NORTH DAKOTA. ANOTHER AREA CONTINUES TO DEVELOP OVER
PORTIONS OF SOUTH CENTRAL NORTH DAKOTA...WHILE A BROAD AREA OVER
CENTRAL SOUTH DAKOTA CONTINUES TO LIFT TOWARDS OUR REGION. FOR THE
MORNING UPDATE...HAVE TRIED TO TIME OUT THE MOTION/ARRIVAL OF
THESE STORMS BASED ON CURRENT TRENDS AND LATEST HRRR GUIDANCE AND
HAVE ADJUSTED POPS ACCORDINGLY. UPDATES HAVE BEEN SENT.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 423 AM CDT FRI SEP 4 2015
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE CHANCES FOR
SHOWERS AND THUNDERSTORMS THROUGH THE PERIOD. HEAVY RAIN POTENTIAL
FAR NORTHWEST THIS MORNING AND POSSIBLY ACROSS THE JAMES RIVER
VALLEY.
CURRENTLY...SOUTH-SOUTHWEST FLOW ALOFT. STRONG EMBEDDED S/WV
IMPULSE LIFTING ACROSS WESTERN SOUTH DAKOTA TOWARDS CENTRAL NORTH
DAKOTA RESULTING IN AN INCREASE IN COVERAGE AND INTENSITY IN
SHOWERS AND THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS THE
PAST FEW HOURS. THE MOST FAVORED AREAS WILL BE ALONG A QUASI-
STATIONARY FRONTAL BOUNDARY DRAPED FROM SOUTHWESTERN NORTH DAKOTA
NORTHEAST THROUGH THE TURTLE MOUNTAINS...AND ACROSS MY NORTHWEST
NEAR A POST FRONTAL AXIS. ANOMALOUS MOISTURE SURGING INTO THE
NORTHERN PLAINS WITH LATEST WATER VAPOR LOOP INDICATING A WELL
DEFINED MID/UPPER LEVEL MOISTURE FEED FROM TROPICAL STORM FRED
SOUTHWEST OF BAJA CALIFORNIA. WARM MID-ATMOSPHERIC PROFILE
SUGGESTS A MORE LOCALIZED HEAVY RAIN THREAT VERSUS WIDESPREAD.
WILL CONTINUE TO MONITOR.
AS MENTIONED ABOVE...AND AS HIGH RES AND LATEST NAM MODEL
SUGGEST...NORTHWESTERN NORTH DAKOTA AND THE JAMES RIVER VALLEY
LOOK HAVE THE GREATEST POTENTIAL AT THIS TIME FOR HEAVY RAINFALL.
VIGOROUS CONVECTION OVER SOUTHEASTERN SASKATCHEWAN SHOWING SOME
SIGNS OF DEVELOPING SOUTH INTO MY NORTHWEST. CONVECTIVE COMPLEX
OVER CENTRAL SOUTH DAKOTA MOVING NORTH WHICH LATEST NAM AND HRRR
BRING INTO THE JAMES RIVER BASIN 12-15Z OR SO. VERY UNSEASONABLE
HIGH DEWPOINT TEMPERATURES OUT THERE IN THE 60S TO LOW 70S
CENTRAL AND EAST.
EMBEDDED WAVE CONTINUES TO LIFT NORTH-NORTHEAST TODAY AND EXPECT
CLEARING SKIES AND DECREASING CHANCES FOR SHOWERS/THUNDERSTORMS
FROM SOUTH TO NORTH IN THE WAVE`S WAKE THIS AFTERNOON. LATEST SPC
OUTLOOK MOVED THE SLIGHT RISK AREA INTO MAINLY THE RED RIVER
VALLEY OF EASTERN NORTH DAKOTA...SO OPTED TO REMOVE SEVERE WORDING
IN OUR PRODUCTS. MODELS HINTING AT LOW LEVEL STRATUS/FOG DEVELOPING
TONIGHT WITH LOW LEVEL MOISTURE REMAINING HIGH COUPLED WITH
FORECAST RAINFALL TODAY.
NEXT STRONG EMBEDDED WAVE LIFTS NORTH-NORTHEAST LATE TONIGHT INTO
SATURDAY...WITH INCREASING POPS WEST LATE TONIGHT THEN SPREADING
EAST AND NORTH ACROSS THE REMAINDER OF THE STATE DURING THE DAY
SATURDAY.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 359 AM CDT FRI SEP 4 2015
UPPER LEVEL TROUGH CLOSES OFF TOWARDS NORTHERN MONTANA THROUGH THE
NIGHT ON SATURDAY WITH PRECIPITATION CHANCES SLOWLY TAPERING OFF
THROUGH THE NIGHT FROM SOUTH TO NORTH. ON SUNDAY...GREATEST
CHANCES WILL BE RESTRICTED TO NORTHERN PORTIONS OF THE AREA AS
UPPER LOW STARTS TO WORK ITS WAY TOWARDS THE EAST/NORTHEAST ACROSS
THE SOUTHERN PRAIRIE PROVINCES. DRY CONDITIONS EXPECTED OVER MOST
LOCATIONS BY SUNDAY NIGHT. BREEZY/WINDY CONDITIONS EXPECTED ON
SUNDAY AS SYSTEM BECOMES STACKED.
MAINLY DRY CONDITIONS EXPECTED ON MONDAY WITH COOLING TREND
CONTINUING AS LOW CONTINUES ITS TRACK NORTH OF THE AREA. THIS WILL
BRING CONTINUED BREEZY CONDITIONS OVER NORTHERN LOCATIONS. MAINLY
DRY CONDITIONS EXPECTED THROUGH MID-WEEK WITH A GRADUAL WARMING
TREND EXPECTED AS RIDGE BUILDS OVER WESTERN CONUS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 628 AM CDT FRI SEP 4 2015
PATCHY FOG AND LOW STRATUS POTENTIAL THROUGH MID MORNING WITH VERY
HIGH BOUNDARY LAYER MOISTURE ACROSS THE REGION. WESTERN TERMINALS
WILL SEE -SHRA AND VCTS NOW THROUGH MID MORNING...SPREADING EAST
MID MORNING THROUGH THE AFTERNOON. AT LEAST PARTIAL CLEARING
EXPECTED FROM SOUTH TO NORTH TODAY INTO THIS EVENING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JJS
SHORT TERM...NH
LONG TERM...JJS
AVIATION...NH
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
807 AM EDT FRI SEP 4 2015
.SYNOPSIS...
AN UPPER AIR DISTURBANCE OVER LOWER MICHIGAN WILL CONTINUE TO
DRIFT SOUTHEAST AND WEAKEN TODAY. A BROAD AREA OF HIGH PRESSURE
AT THE SURFACE AND ALOFT FROM THE MIDWEST TO EASTERN CANADA WILL
REMAIN NEARLY STATIONARY THROUGH LABOR DAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A NICE AREA OF RAIN CONTINUES TO DRIFT ACROSS THE CENTRAL PORTION
OF THE AREA. HEAVY RAIN CURRENTLY FALLING AT KCLE. HAVE BUMPED UP
PRECIP CHANCES A LITTLE FOR THE NEXT FEW HOURS IN THE EAST. WITH
ALL OF THE OUTFLOW BOUNDARIES FLOATING AROUND EXPECT TO CONTINUE
TO SEE NEW STORMS POPPING UP.
A PREVIOUS...SHOWERS AND THUNDERSTORMS CONTINUE TO MOVE AND
REDEVELOP ACROSS NORTH CENTRAL OHIO THIS MORNING. THERE HAS BEEN A
DECREASE IN INTENSITY AND LIGHTNING THE PAST COUPLE OF HOURS BUT
THE LATEST HRRR TAKES THIS AREA OF PRECIP ALL THE WAY TO THE PA
BORDER BY 12Z. WILL KEEP SCATTERED WORDING GOING THROUGH DAYBREAK
OR SO AND THEN BRIEFLY DIMINISH PRECIP CHANCES FOR THE MORNING
HOURS. MORE SHOWERS AND STORMS ARE EXPECTED THIS AFTERNOON. THE
00Z GUIDANCE...ESPECIALLY THE NAM IS SHOWING OVER 4000 J/KG CAPES
THIS AFTERNOON. AND...UNLIKE THE PREVIOUS COUPLE OF DAYS...BETTER
TRIGGERS IN THE FORM OF LEFT OVER BOUNDARIES FROM TONIGHT`S
CONVECTION WILL BE FLOATING AROUND TO KICK OFF NEW STORMS. TOUGH
TO TELL WHEN AND WHERE THE STORMS WILL INITIATE SO WILL KEEP A
GENERIC SCATTERED WORDING MOST OF THE DAY. IF I HAD TO GUESS I
WOULD SAY COVERAGE OF THE STORMS WILL BE THE GREATEST IN THE WEST
AND SOUTHWEST ENDS OF THE AREA. LOT`S OF CLOUDS RIGHT NOW BUT THEY
SHOULD THIN AND ALLOW AT LEAST SOME PARTIAL SUNSHINE.
KCLE GOT TO 90 YESTERDAY AND SEE NO REASON WHY TEMPS WILL BE MUCH
COOLER TODAY AS TEMPS ALOFT REMAIN ABOUT THE SAME. KCAK HAS BEEN
89 OR 90 THE PAST THREE DAYS AS WELL. WILL GO WITH A PERSISTENCE
FORECAST UNTIL FURTHER NOTICE. UPPER 80S LIKELY MOST AREAS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
UPPER RIDGING WILL OCCUR OVER THE AREA THIS WEEKEND BUT IT WILL
TAKE SOME TIME FOR THE DISTURBANCE OVER THE REGION TO DISSIPATE.
EXPECT ONGOING PRECIP THIS EVENING BUT WILL TRY TO DRY THINGS OUT
AFTER MIDNIGHT. EXPECT MORE ISOLATED TO SCATTERED SHOWERS AND
STORMS ON SATURDAY AS A WARM AND HUMID AIRMASS WILL REMAIN
OVERHEAD. BOUNDARIES LEFT OVER FROM THE PREVIOUS DAY AND NIGHTS
STORMS WILL BE THE MAIN TRIGGER FOR WEEKEND CONVECTION. WILL TRY
FOR DRY DAYS SUNDAY AND MONDAY BUT WILL PROBABLY STILL SEE A FEW
POP UPS EACH DAY. THE NEXT FRONTAL SYSTEM WILL BEGIN TO APPROACH
FROM THE NORTHWEST ON MONDAY NIGHT. THE 00Z MODELS HAVE DIFFERENT
OPINIONS ON WHEN THE FRONT WILL ARRIVE WITH THE ECMWF SLOWER THAN
THE GFS. ALREADY HAD CHANCE POPS OVER THE NW HALF OF THE AREA
MONDAY NIGHT AND IT IS PROBABLY PRUDENT TO LEAVE THEM IN EVEN
THOUGH BETTER CHANCES WILL OCCUR IN THE LONG TERM PERIOD.
NOT MUCH CHANGE IN TEMPS IS EXPECTED OVER THE WEEKEND WITH
PERSISTENCE THE WAY TO GO FOR TEMPS.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
ONE MORE DAY OF WELL ABOVE NORMAL TEMPERATURES ON TUESDAY TO START
THE EXTENDED FORECAST WITH TEMPERATURES FALLING TO BELOW NORMAL BY
THE END OF THE WEEK. THE UPPER LEVEL PATTERN WILL FEATURE A BROAD
TROUGH OVER THE MID-SECTION OF THE COUNTRY THAT SLOWLY MOVES EAST
AND FLATTENS THE PERSISTENT UPPER LEVEL RIDGE. A STALLED FRONTAL
BOUNDARY WILL BE LOCATED NEAR OR JUST NORTH OF LAKE ERIE TO START
THE DAY ON TUESDAY. THE GFS REMAINS FASTER THAN THE CANADIAN/ECMWF
WITH WHAT APPEARS TO BE SOME SPURIOUS UPPER LEVEL ENERGY DRIVING THE
FORWARD PROGRESSION OF THE FRONT. THE ATMOSPHERE REMAINS RELATIVELY
DRY OUT AHEAD OF THE FRONT AND OPTED TO KEEP POPS FAIRLY LOW IN THE
EAST ON TUESDAY IN AGREEMENT WITH THE SLOWER MODELS. CHANCES FOR
PRECIPITATION INCREASING DURING THE TUESDAY NIGHT THROUGH WEDNESDAY
NIGHT PERIOD AS THE UPPER TROUGH MOVES THROUGH THE CENTRAL GREAT
LAKES WITH THE EVENTUAL PASSAGE OF A STRONG COLD FRONT EARLY
THURSDAY. SUSPECT THERE WILL BE GOOD COVERAGE OF PRECIPITATION AT
LEAST ONE OF THE PERIODS BUT STILL TOO MUCH UNCERTAINTY IN EVOLUTION
TO GO MORE THAN CHANCE POPS.
TEMPERATURES WILL START OUT IN THE UPPER 80S ON TUESDAY...DROP BACK
TO THE LOWER 80S WITH INCREASING CLOUDS AND THUNDERSTORMS ON
WEDNESDAY AND SETTLE INTO THE LOW TO MID 70S WITH LOWER HUMIDITY TO
END THE WEEK.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
REMNANTS OF OVERNIGHT MCS CONTINUE TO MOVE SE WITH SHOWERS AND
THUNDERSTORMS CONTINUING FROM CLE-CAK AT TAF ISSUANCE. THIS AREA OF
PRECIPITATION WILL TEND TO DECREASE FROM THE NORTH THROUGH 15Z.
ADDITIONAL SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP TODAY
WITH AN UPPER WAVE OVER LOWER MICHIGAN. SEVERAL OF THE HIGH- RES
MODELS ARE SHOWING SCATTERED SHOWERS DEVELOPING BY 15-16Z WITH
DIURNAL HEATING. THUNDERSTORMS WILL INCREASE THROUGH THE AFTERNOON
IN AREAS OF CONVERGENCE AND REMANT OUTFLOW BOUNDARIES...ESPECIALLY
ACROSS NORTHWEST OHIO WHERE INSTABILITY WILL BE GREATEST. ANY
THUNDERSTORM TODAY WILL RESULT IN BRIEF HEAVY RAIN WITH MVFR TO
LOCALLY IFR VISIBILITIES. COVERAGE OF SHOWERS AND THUNDERSTORMS
WILL DECREASE TONIGHT WITH PATCHY GROUND FOG DEVELOPING IF WE
CLEAR OUT. MOST SITES WILL DROP TO MVFR VISIBILITIES LATE TONIGHT.
OUTLOOK...AREAS OF NON VFR EACH MORNING IN FOG AND HAZE. SCATTERED
THUNDERSTORMS MAY DEVELOP AGAIN SATURDAY...BECOMING MORE ISOLATED
BY SUNDAY.
&&
.MARINE...
EASTERLY WINDS TODAY WILL VEER TO SOUTHERLY OVERNIGHT. WITH HIGH
PRESSURE OVER THE EASTERN GREAT LAKES...EXPECT TO SEE LAKE BREEZES
DEVELOP ON SATURDAY AND TO POSSIBLY ON THE EAST END OF THE LAKE ON
SUNDAY. OTHERWISE LIGHT SOUTH TO SOUTHWEST WINDS WILL CONTINUE
DURING THE FIRST HALF OF THE WEEK WITH A STRONG COLD FRONT PUSHING
SOUTH ACROSS THE LAKE EARLY THURSDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KUBINA
NEAR TERM...KUBINA
SHORT TERM...KUBINA
LONG TERM...KEC
AVIATION...KEC
MARINE...KEC
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
635 AM EDT FRI SEP 4 2015
.SYNOPSIS...
AN UPPER AIR DISTURBANCE OVER LOWER MICHIGAN WILL CONTINUE TO
DRIFT SOUTHEAST AND WEAKEN TODAY. A BROAD AREA OF HIGH PRESSURE
AT THE SURFACE AND ALOFT FROM THE MIDWEST TO EASTERN CANADA WILL
REMAIN NEARLY STATIONARY THROUGH LABOR DAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A NICE AREA OF RAIN CONTINUES TO DRIFT ACROSS THE CENTRAL PORTION
OF THE AREA. HEAVY RAIN CURRENTLY FALLING AT KCLE. HAVE BUMPED UP
PRECIP CHANCES A LITTLE FOR THE NEXT FEW HOURS IN THE EAST. WITH
ALL OF THE OUTFLOW BOUNDARIES FLOATING AROUND EXPECT TO CONTINUE
TO SEE NEW STORMS POPPING UP.
A PREVIOUS...SHOWERS AND THUNDERSTORMS CONTINUE TO MOVE AND
REDEVELOP ACROSS NORTH CENTRAL OHIO THIS MORNING. THERE HAS BEEN A
DECREASE IN INTENSITY AND LIGHTNING THE PAST COUPLE OF HOURS BUT
THE LATEST HRRR TAKES THIS AREA OF PRECIP ALL THE WAY TO THE PA
BORDER BY 12Z. WILL KEEP SCATTERED WORDING GOING THROUGH DAYBREAK
OR SO AND THEN BRIEFLY DIMINISH PRECIP CHANCES FOR THE MORNING
HOURS. MORE SHOWERS AND STORMS ARE EXPECTED THIS AFTERNOON. THE
00Z GUIDANCE...ESPECIALLY THE NAM IS SHOWING OVER 4000 J/KG CAPES
THIS AFTERNOON. AND...UNLIKE THE PREVIOUS COUPLE OF DAYS...BETTER
TRIGGERS IN THE FORM OF LEFT OVER BOUNDARIES FROM TONIGHT`S
CONVECTION WILL BE FLOATING AROUND TO KICK OFF NEW STORMS. TOUGH
TO TELL WHEN AND WHERE THE STORMS WILL INITIATE SO WILL KEEP A
GENERIC SCATTERED WORDING MOST OF THE DAY. IF I HAD TO GUESS I
WOULD SAY COVERAGE OF THE STORMS WILL BE THE GREATEST IN THE WEST
AND SOUTHWEST ENDS OF THE AREA. LOT`S OF CLOUDS RIGHT NOW BUT THEY
SHOULD THIN AND ALLOW AT LEAST SOME PARTIAL SUNSHINE.
KCLE GOT TO 90 YESTERDAY AND SEE NO REASON WHY TEMPS WILL BE MUCH
COOLER TODAY AS TEMPS ALOFT REMAIN ABOUT THE SAME. KCAK HAS BEEN
89 OR 90 THE PAST THREE DAYS AS WELL. WILL GO WITH A PERSISTENCE
FORECAST UNTIL FURTHER NOTICE. UPPER 80S LIKELY MOST AREAS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
UPPER RIDGING WILL OCCUR OVER THE AREA THIS WEEKEND BUT IT WILL
TAKE SOME TIME FOR THE DISTURBANCE OVER THE REGION TO DISSIPATE.
EXPECT ONGOING PRECIP THIS EVENING BUT WILL TRY TO DRY THINGS OUT
AFTER MIDNIGHT. EXPECT MORE ISOLATED TO SCATTERED SHOWERS AND
STORMS ON SATURDAY AS A WARM AND HUMID AIRMASS WILL REMAIN
OVERHEAD. BOUNDARIES LEFT OVER FROM THE PREVIOUS DAY AND NIGHTS
STORMS WILL BE THE MAIN TRIGGER FOR WEEKEND CONVECTION. WILL TRY
FOR DRY DAYS SUNDAY AND MONDAY BUT WILL PROBABLY STILL SEE A FEW
POP UPS EACH DAY. THE NEXT FRONTAL SYSTEM WILL BEGIN TO APPROACH
FROM THE NORTHWEST ON MONDAY NIGHT. THE 00Z MODELS HAVE DIFFERENT
OPINIONS ON WHEN THE FRONT WILL ARRIVE WITH THE ECMWF SLOWER THAN
THE GFS. ALREADY HAD CHANCE POPS OVER THE NW HALF OF THE AREA
MONDAY NIGHT AND IT IS PROBABLY PRUDENT TO LEAVE THEM IN EVEN
THOUGH BETTER CHANCES WILL OCCUR IN THE LONG TERM PERIOD.
NOT MUCH CHANGE IN TEMPS IS EXPECTED OVER THE WEEKEND WITH
PERSISTENCE THE WAY TO GO FOR TEMPS.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
ONE MORE DAY OF WELL ABOVE NORMAL TEMPERATURES ON TUESDAY TO START
THE EXTENDED FORECAST WITH TEMPERATURES FALLING TO BELOW NORMAL BY
THE END OF THE WEEK. THE UPPER LEVEL PATTERN WILL FEATURE A BROAD
TROUGH OVER THE MID-SECTION OF THE COUNTRY THAT SLOWLY MOVES EAST
AND FLATTENS THE PERSISTENT UPPER LEVEL RIDGE. A STALLED FRONTAL
BOUNDARY WILL BE LOCATED NEAR OR JUST NORTH OF LAKE ERIE TO START
THE DAY ON TUESDAY. THE GFS REMAINS FASTER THAN THE CANADIAN/ECMWF
WITH WHAT APPEARS TO BE SOME SPURIOUS UPPER LEVEL ENERGY DRIVING THE
FORWARD PROGRESSION OF THE FRONT. THE ATMOSPHERE REMAINS RELATIVELY
DRY OUT AHEAD OF THE FRONT AND OPTED TO KEEP POPS FAIRLY LOW IN THE
EAST ON TUESDAY IN AGREEMENT WITH THE SLOWER MODELS. CHANCES FOR
PRECIPITATION INCREASING DURING THE TUESDAY NIGHT THROUGH WEDNESDAY
NIGHT PERIOD AS THE UPPER TROUGH MOVES THROUGH THE CENTRAL GREAT
LAKES WITH THE EVENTUAL PASSAGE OF A STRONG COLD FRONT EARLY
THURSDAY. SUSPECT THERE WILL BE GOOD COVERAGE OF PRECIPITATION AT
LEAST ONE OF THE PERIODS BUT STILL TOO MUCH UNCERTAINTY IN EVOLUTION
TO GO MORE THAN CHANCE POPS.
TEMPERATURES WILL START OUT IN THE UPPER 80S ON TUESDAY...DROP BACK
TO THE LOWER 80S WITH INCREASING CLOUDS AND THUNDERSTORMS ON
WEDNESDAY AND SETTLE INTO THE LOW TO MID 70S WITH LOWER HUMIDITY TO
END THE WEEK.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
A LARGE AREA OF SHOWERS AND THUNDERSTORMS ACROSS NORTH CENTRAL OHIO
WILL CONTINUE TO MOVE EAST SOUTHEAST OVERNIGHT. EXPECT THE COVERAGE
OF THUNDERSTORMS TO TEND TO DIMINISH WITH TIME...BUT NOT BEFORE
BRINGING ANOTHER ROUND OF THUNDERSTORMS TO CLE/MFD/CAK AND POSSIBLY
THROUGH 09Z WITH LESSER CHANCES AT YNG/ERI IF MCS HOLDS TOGETHER. A
LOW STRATUS DECK HAS BEEN TRYING TO DEVELOP AND EXPECT THIS TO BE
SOMEWHAT VARIABLE OVERNIGHT. VISIBILITIES WILL TEND TO SETTLE INTO
THE MVFR RANGE BUT A FEW SITES WILL LIKELY DIP INTO THE IFR
VISIBILITY RANGE.
SCATTERED THUNDERSTORMS EXPECTED TO DEVELOP AGAIN ON FRIDAY BUT
TIMING WILL AGAIN BE A CHALLENGE. SUFFICIENT INSTABILITY SHOULD BE
IN PLACE FOR SHOWERS AND THUNDERSTORMS TO FIRE ALONG REMNANT OUTFLOW
BOUNDARIES BY MID DAY. TIMING THUNDERSTORMS INTO THE INDIVIDUAL
TERMINALS WILL NEED TO BE REFINED.
OUTLOOK...AREAS OF NON VFR EACH MORNING IN FOG AND HAZE. ISOLATED
THUNDERSTORMS MAY DEVELOP EACH AFTERNOON/EVENING THROUGH SATURDAY.
&&
.MARINE...
EASTERLY WINDS TODAY WILL VEER TO SOUTHERLY OVERNIGHT. WITH HIGH
PRESSURE OVER THE EASTERN GREAT LAKES...EXPECT TO SEE LAKE BREEZES
DEVELOP ON SATURDAY AND TO POSSIBLY ON THE EAST END OF THE LAKE ON
SUNDAY. OTHERWISE LIGHT SOUTH TO SOUTHWEST WINDS WILL CONTINUE
DURING THE FIRST HALF OF THE WEEK WITH A STRONG COLD FRONT PUSHING
SOUTH ACROSS THE LAKE EARLY THURSDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KUBINA
NEAR TERM...KUBINA
SHORT TERM...KUBINA
LONG TERM...KEC
AVIATION...KEC
MARINE...KEC
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
223 AM EDT FRI SEP 4 2015
.SYNOPSIS...
UNSTABLE AIRMASS CONTINUES INTO FRIDAY. CONVECTION MOST COMMON
DURING THE AFTERNOON AND EVENING...BUT COULD ISOLATED AREAS COULD
LINGER OVERNIGHTS. SOUTHEAST FLOW INCREASES FRIDAY NIGHT INTO SATURDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
INCREASED POPS N WHILE DRYING OUT SWRN PORTIONS OF THE FCST AREA
OVERNIGHT..GIVEN THUNDERSTORM COMPLEX DRIFTING SWD INTO THE
MIDDLE OHIO VALLEY OVERNIGHT WAS LOCATED RIGHT IN THE DIFFLUENT
ZONE JUST SE OF AN UPPER LEVEL LOW OVER LOWER MICHIGAN.
PREV DISCN...
LOCAL DOWNPOURS VERSUS THE HEAT THURSDAY AFTERNOON. ANOTHER NIGHT
THAT WE CAN NOT REMOVE THE CHANCE OF RAIN TOTALLY. RAP SHOWS A
WEAK VORT MAX IN CENTRAL OHIO DRIFTING EAST AND SOUTH.
DESPITE THE LINGERING CONVECTION...STILL HAVE AREAS OF FOG
FORMING...ESPECIALLY IN AREAS THAT HAD RAIN. YET...THE LINGERING
PATCHES OF CLOUDS COULD INTERFERE WITH THE FOG FORMATION. SO
ANOTHER HARD HOUR BY HOUR FORECAST CONCERNING THE FOG FOR 06Z TO
12Z FRIDAY.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
STAGNANT PATTERN THIS WEEKEND AMID UPPER LEVEL RIDGING OVER THE E
CONUS. THERE IS JUST ENOUGH OF A WEAKNESS OVER THE REGION THAT
COMBINED WITH AFTERNOON HEATING...THERE SHOULD BE DIURNAL POPCORN
SHRA/TSRA MAXIMIZED OVER THE MOUNTAINS. STILL...LOW POPS WITH
ISOLATED COVERAGE. TEMPS WILL GENERALLY RUN 5 TO 10 DEGREES ABOVE
NORMAL AND DEWPOINTS ON THE MUGGY SIDE.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
MORE OF THE SAME THROUGH WEDNESDAY...HOT AND MUGGY CONDITIONS WITH
JUST AN ISOLATED SHRA/TSRA. PATTERN FINALLY BEGINS TO BREAK TOWARD
THURSDAY WITH FALLING HEIGHTS AMID A TRANSITION MORE INTO A E
CONUS TROF. THE COLD FRONT THAT WILL MARK THIS TRANSITION LOOKS TO
CROSS LONG ABOUT THURSDAY. IT IS LOOKING LIKE A WAVE WILL DEVELOP
ALONG THE FRONT WITH A GOOD SHOT A MUCH NEEDED RAIN OVER THE
AREA...PARTICULARLY ALONG THE OH RIVER.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
VALLEY FOG FORMATION WAS ALREADY WELL UNDERWAY...BUT A
THUNDERSTORM COMPLEX MOVING SEWD INTO THE MIDDLE OHIO VALLEY MAY
CAUSE THE FOG TO BREAK UP THERE...AND THE CHANCE FOR A
THUNDERSTORM IMPACTING AN AIRPORT DIRECTLY DEPENDS UPON TO WHAT
DEGREE THE COMPLEX HOLDS TOGETHER OVERNIGHT. PKB AND PERHAPS CKB
ARE MORE LIKELY TO BE IMPACTED OVERNIGHT...VERSUS POINTS FARTHER
TO THE S AND E.
DAYBREAK WILL BRING AN END TO BOTH FOG AND THUNDER CONCERNS BY MID
MORNING...BUT SCATTERED AFTERNOON CONVECTION WILL FIRE UP AGAIN
FRI AFTERNOON...AS AN UPPER LEVEL DISTURBANCE OVER OHIO
OVERNIGHT...DRIFTS OVER WV FRI.
FRI NT WILL BE ANOTHER TOUGH CALL. ON THE ONE HAND...AFTERNOON AND
EVENING RAINFALL GREATLY INCREASES THE CHANCE OF AND HASTENS THE
TIMING OF THE FORMATION OF OVERNIGHT FOG. ON THE OTHER
HAND...OVERNIGHT CONVECTION INTERFERES WITH DENSE FOG.
MAINLY CALM SFC WIND OVERNIGHT WILL BE LIGHT AND VARIABLE...MAINLY
N...ON FRI...AND THEN LIGHT AND VARIABLE FRI NT. LIGHT N TO NE
FLOW ALOFT OVERNIGHT AND FRI WILL BECOME LIGHT NE TO E FRI NT.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SATURDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING AND COVERAGE OF FOG OVERNIGHT MAY
VARY FROM FORECAST. MAY NEED AMENDMENTS AND TEMPOS IF STORMS
FORM/MOVE TOWARDS TERMINALS AT ANYTIME.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE FRI 09/04/15
UTC 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14
EDT 1HRLY 23 00 01 02 03 04 05 06 07 08 09 10
CRW CONSISTENCY H H M M M L L L L L M M
HTS CONSISTENCY H H H M M L L L L L H M
BKW CONSISTENCY H H H H H H H H H H H M
EKN CONSISTENCY M M L L L L L L L L M M
PKB CONSISTENCY M M M L L L L L L L M M
CKB CONSISTENCY H M M L L L L L L L M M
AFTER 06Z SATURDAY...
IFR POSSIBLE IN VALLEY FOG OVERNIGHT FRIDAY NIGHT INTO SATURDAY
MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...30/26
NEAR TERM...KTB/TRM
SHORT TERM...30
LONG TERM...30
AVIATION...TRM
AREA FORECAST DISCUSSION
NWS PORTLAND OR
850 PM PDT SAT SEP 5 2015
.SYNOPSIS...A WEAK FRONT WILL MOVE DOWN THE WASHINGTON COAST INTO
OREGON OVERNIGHT AND WILL BRING SOME LIGHT RAIN TO THE COAST...AND
POSSIBLY NORTHERN INLAND AREAS TONIGHT AND SUNDAY. DRY WEATHER IS
EXPECTED FOR LABOR DAY AS A WEAK UPPER RIDGE BUILDS INTO THE REGION.
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 SHOWERS FROM TODAYS WEAK CONVECTION HAVE ENDED BUT
SOME LIGHT RAIN IS SLIDING DOWN THE WASHINGTON COAST FROM THE AREA
NORTH OF WILLAPA BAY AS A UPPER SHORT WAVE AND WEAK FRONTAL SYSTEM
SLIDES DOWN THE COAST. I HAVE RAISED THE CHANCE OF RAIN A BIT OVER
SOUTHWEST WASHINGTON AND INTO THE NORTH OREGON COAST AND NORTH
WILLAMETTE VALLEY FOR THE REMAINDER OF THIS EVENING AND THROUGH
SUNDAY MORNING. THE HRRR MODEL HAS BEEN INDICATING A LITTLE FASTER
PROGRESSION OF PRECIPITATION WITH THIS SYSTEM AND IT SEEMS TO BE
VERIFYING WELL. MODELS CONTINUE TO INDICATE THIS SYSTEM WILL WEAKEN
BY SUNDAY AFTERNOON WITH THE MAIN THREAT OF SHOWERS IN THE NORTHERN
ZONES AND OVER SOUTHWEST WASHINGTON AND THE FAR NORTH WILLAMETTE
VALLEY. CLOUDINESS SUNDAY SHOULD KEEP TEMPERATURES AROUND 70 DEGREES
INLAND FROM SALEM NORTHWARD...BUT FEWER CLOUDS SOUTH COULD LET
EUGENE WARM INTO THE MID 70S.
SCHNEIDER
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...VFR CONDITIONS PREVAIL THIS EVENING WITH A FEW
RESIDUAL SHOWERS ASSOCIATED WITH A WEAK DISTURBANCE THAT MOVED
OVER THE AREA THIS AFTERNOON. EXPECT SHOWERS TO DISSIPATE BY 04Z
SUN. THE MAIN FRONTAL SYSTEM WILL MOVE ACROSS THE REGION LATE
TONIGHT THROUGH SUNDAY MORNING...WITH RAIN AND MVFR CIGS REACHING
THE COAST AROUND 07Z-09Z SUN. 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 AFTER 20Z LATE SUNDAY.
KPDX AND APPROACHES...VFR NEXT 24 HRS. CLOUD COVER AND RAIN
CHANCES INCREASE AFTER 10Z...WITH REDUCED CIGS AROUND 4K FT AND
VSBY POSSIBLE UNDER HEAVIER RAIN BANDS. VFR CONDITIONS RETURNS
BETWEEN 18Z-21Z SUNDAY. /64/27
&&
.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 MEDFORD OR
1258 PM PDT FRI SEP 4 2015
.DISCUSSION...THE UPPER LOW IS NOW CENTERED OVER WESTERN WASHINGTON
AND WILL CONTINUE TO MOVE SOUTH OVER THE AREA LATE THIS AFTERNOON.
SHOWERS AND ISOLATED THUNDERSTORMS WILL INCREASE OVER TIME AS THE
UPPER LOW AND COLD AIR ALOFT (-25C AT 500MB) MOVES OVERHEAD, THUS
INCREASING INSTABILITY. THE LATEST HRRR MODEL RUN SHOWS MOST OF THE
SHOWERS AND ISOLATED THUNDERSTORMS ALONG AND EAST OF THE CASCADES,
BUT SUSPECT IT MAY BE UNDERESTIMATING THE CONVECTIVE ACTIVITY WEST
OF THE CASCADES. THEREFORE WE`LL CONTINUE TO KEEP POPS HIGHER WEST
OF THE CASCADES INTO THIS EVENING. IN ADDITION THERE`S A CHANCE SOME
THUNDERSTORMS COULD PRODUCE GUSTY WINDS AND SMALL HAIL.
THE 12Z NAM AND GFS SHOW THE TROUGH AXIS MOVING EAST OF THE CASCADES
LATE TONIGHT AT WHICH POINT THE BULK OF THE PRECIPITATION WILL SHIFT
INTO LAKE, MODOC AND EASTERN KLAMATH COUNTY. A COLDER AIR MASS WILL
SETTLE INTO THE AREA TONIGHT, BUT THERE MAY A SUFFICIENT AMOUNT OF
CLOUD COVER REMAINING IN THE AREA, SO NIGHTTIME LOWS MAY NOT DROP AS
LOW AS WOULD BE EXPECTED. WE`LL KEEP PATCHY FROST TO THE FORECAST,
BUT GIVEN THE CLOUD COVER, DO NOT THINK THAT THIS WOULD BE A
WIDESPREAD EVENT. EVEN THEN NEAR FREEZING TEMPERATURES MAY ONLY LAST
FOR AN HOUR OR TWO NEAR DAYBREAK. SO WILL NOT ISSUE ANY HEADLINES AT
THIS TIME.
THE UPPER TROUGH WILL MOVE EAST SATURDAY MORNING AND WEAK RIDGING
BUILDS IN FROM THE SOUTHWEST. THE DEFORMATION ZONE WILL BE CONFINED
TO EASTERN LAKE AND MODOC COUNTY WITH RAIN AND HIGHER ELEVATION
RAIN/WET SNOW MIX EARLY IN THE MORNING, THEN PLAIN RAIN. THE MODELS
HAVE TRENDED FASTER WITH THE PROGRESSION OF THE UPPER LOW SATURDAY,
SO WE COULD SEE CONDITIONS DRY OUT IN THE AFTERNOON IN EASTERN LAKE
AND MODOC COUNTY. ELSEWHERE IT WILL BE DRY WITH MILDER TEMPERATURES.
CONDITIONS WILL BE DRY SATURDAY NIGHT AND THERE WILL BE LITTLE OR NO
CLOUD COVER. THIS WILL ALLOW RADIATIONAL COOLING TO TAKE PLACE AND
WERE MORE LIKELY TO HAVE WIDESPREAD FREEZING TEMPERATURES EAST OF
THE CASCADES. THEREFORE A FREEZE WATCH WILL BE IN EFFECT FOR
SATURDAY NIGHT INTO EARLY SUNDAY MORNING.
THE COOLER THAN NORMAL TEMPERATURES WILL NOT LAST LONG. THE MODELS
REMAIN IN GOOD AGREEMENT DRY AND WARMER WEATHER RETURNING SUNDAY AND
LASTING INTO MOST OF NEXT WEEK WITH THE THERMAL TROUGH SETTING UP
SUNDAY AND REMAINING A FIXTURE FOR MOST OF NEXT WEEK. IN FACT 850 MB
TEMPERATURES ARE PROJECTED TO INCREASE OVER TIME AND PEAK OUT
BETWEEN 24-26 C NEXT THURSDAY WHICH IF CORRECT COULD RESULT IN
TEMPERATURES IN THE MID TO UPPER 90S FOR THE ROGUE VALLEY.
-PETRUCELLI
&&
.AVIATION...FOR THE 04/18Z TAF CYCLE...
NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS WILL OCCUR TODAY FROM
THE CASCADES EASTWARD, WHILE SHOWERS WILL BE MORE SCATTERED EAST OF
THE COAST RANGE AND WEST OF THE CASCADES. PARTIAL TERRAIN
OBSCURATIONS AND ISOLATED MVFR CONDITIONS ARE EXPECTED IN MORE
SIGNIFICANT WEST SIDE SHOWERS THIS AFTERNOON INTO THIS EVENING. FROM
THE CASCADES EAST EXPECT HIGHER TERRAIN TO BE MOSTLY OBSCURED WITH
MVFR TO ISOLATED IFR IN HEAVIER SHOWERS AND THUNDERSTORMS. THE
FREEZING LEVEL WILL BE AT 8000 FEET TODAY AND THEN WILL FALL
OVERNIGHT TO NEAR THE SURFACE ON THE EAST SIDE. OVERNIGHT AREAS OF
MVFR AND LOCAL IFR IS EXPECTED IN LOW CLOUDS, PRIMARILY ON THE NORTH
AND NORTHWEST SLOPES AND VALLEY EDGES, AND IN THE UMPQUA BASIN. BTL
&&
.MARINE...UPDATED 845 AM PDT FRIDAY 4 SEPTEMBER 2015... NORTH WINDS
WILL CONTINUE THROUGH THE FORECAST PERIOD. A PERIOD OF SMALL CRAFT
ADVISORY LEVEL WINDS IS EXPECTED THIS AFTERNOON AND EVENING IN AN
AREA SOUTH OF CAPE BLANCO BEYOND 10 NAUTICAL MILES OF THE COAST.
WINDS THEN STRENGTHEN AGAIN SUNDAY AS A THERMAL TROUGH FORMS OVER
NORTHERN CALIFORNIA. GALES WILL BE POSSIBLE OVER THE SOUTHERN WATERS
MONDAY AND TUESDAY. SEAS WILL BE PRIMARILY WIND DRIVEN THROUGH EARLY
NEXT WEEK. BTL/WRIGHT
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...FREEZE WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY MORNING FOR
ORZ029>031.
CA...FREEZE WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY MORNING FOR
CAZ085.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR PZZ376.
$$
AREA FORECAST DISCUSSION
NWS MEDFORD OR
1139 AM PDT FRI SEP 4 2015
.DISCUSSION...THE UPPER LOW IS NOW CENTERED OVER WESTERN
WASHINGTON AND WILL CONTINUE TO MOVE SOUTH OVER THE AREA LATE
THIS AFTERNOON. A LINE OF SHOWERS AND ISOLATED THUNDERSTORMS BROKE
OUT IN ADVANCE OF AN SHORTWAVE TROUGH ROTATING AROUND THE UPPER
LOW WHICH IS NOW IN NORTHWEST CAL. SHOWERS AND ISOLATED
THUNDERSTORMS WILL INCREASE OVER TIME AS THE UPPER LOW AND COLD
AIR ALOFT (-25C AT 500MB) MOVES OVERHEAD INCREASING INSTABILITY.
THE LATEST HRRR MODEL RUN SHOWS MOST OF THE SHOWERS AND ISOLATED
THUNDERSTORMS ALONG AND EAST OF THE CASCADES, BUT SUSPECT IT MAY
BE UNDERESTIMATING THE CONVECTIVE ACTIVITY WEST OF THE CASCADES.
THEREFORE WE`LL CONTINUE TO KEEP POPS HIGHER WEST OF THE CASCADES
THIS AFTERNOON. IN ADDITION THERE`S A CHANCE SOME THUNDERSTORMS
COULD PRODUCE GUSTY WINDS AND SMALL HAIL.
THE 12Z NAM AND GFS SHOW THE TROUGH AXIS MOVING EAST OF THE
CASCADES LATE TONIGHT AT WHICH POINT THE BULK OF THE PRECIPITATION
WILL SHIFT INTO LAKE, MODOC AND EASTERN KLAMATH COUNTY. SATURDAY
IS STILL A TRANSITION DAY WITH ANY SHOWERS CONFINED TO EASTERN
LAKE COUNTY IN THE MORNING AND DRY CONDITIONS ELSEWHERE.
-PETRUCELLI
&&
.AVIATION...FOR THE 04/18Z TAF CYCLE... NUMEROUS SHOWERS AND
ISOLATED THUNDERSTORMS WILL OCCUR TODAY FROM THE CASCADES EASTWARD,
WHILE SHOWERS WILL BE MORE SCATTERED EAST OF THE COAST RANGE AND
WEST OF THE CASCADES. PARTIAL TERRAIN OBSCURATIONS AND ISOLATED MVFR
CONDITIONS ARE EXPECTED IN MORE SIGNIFICANT WEST SIDE SHOWERS THIS
AFTERNOON INTO THIS EVENING. FROM THE CASCADES EAST EXPECT HIGHER
TERRAIN TO BE MOSTLY OBSCURED WITH MVFR TO ISOLATED IFR IN HEAVIER
SHOWERS AND THUNDERSTORMS. THE FREEZING LEVEL WILL BE AT 8000 FEET
TODAY AND THEN WILL FALL OVERNIGHT TO NEAR THE SURFACE ON THE EAST
SIDE. OVERNIGHT AREAS OF MVFR AND LOCAL IFR IS EXPECTED IN LOW
CLOUDS, PRIMARILY ON THE NORTH AND NORTHWEST SLOPES AND VALLEY
EDGES, AND IN THE UMPQUA BASIN. BTL
&&
.MARINE...UPDATED 845 AM PDT FRIDAY 4 SEPTEMBER 2015... NORTH WINDS
WILL CONTINUE THROUGH THE FORECAST PERIOD. A PERIOD OF SMALL CRAFT
ADVISORY LEVEL WINDS IS EXPECTED THIS AFTERNOON AND EVENING IN AN
AREA SOUTH OF CAPE BLANCO BEYOND 10 NAUTICAL MILES OF THE COAST.
WINDS THEN STRENGTHEN AGAIN SUNDAY AS A THERMAL TROUGH FORMS OVER
NORTHERN CALIFORNIA. GALES WILL BE POSSIBLE OVER THE SOUTHERN WATERS
MONDAY AND TUESDAY. SEAS WILL BE PRIMARILY WIND DRIVEN THROUGH EARLY
NEXT WEEK. BTL/WRIGHT
&&
.PREV DISCUSSION... /ISSUED 639 AM PDT FRI SEP 4 2015/
UPDATE...PUT OUT A QUICK UPDATE JUST NOW TO INCREASE POPS ON THE
EAST SIDE AND ALLOW FOR THUNDERSTORMS OVER ALL AREAS THIS MORNING.
AIR MASS IS ALREADY DESTABILIZING QUICKLY AND WE`VE SEEN SIX
LIGHTNING STRIKES ALONG THE SISKIYOU/MODOC BORDER, AND THIS IS
WITH THE MAJORITY OF THE COLD POOL AND INSTABILITY YET TO COME
TODAY. IT ALSO WOULDN`T BE OUT OF THE QUESTION TO SEE A FEW
SNOWFLAKES OVER LAKE AND MODOC COUNTIES THIS MORNING AS SURFACE
TEMPERATURES ARE NEAR OR BELOW FREEZING. TEMP/DEWPOINT SPREAD ARE
FAIRLY HIGH, THOUGH, SO IT MAY BE JUST VIRGA OUT THERE. -WRIGHT
PREV DISCUSSION... /ISSUED 325 AM PDT FRI SEP 4 2015/
DISCUSSION...TEMPERATURES THIS MORNING HAVE BEEN QUITE COLD
RELATIVE TO NORMAL FOR THIS TIME OF YEAR, WITH TEMPERATURES EVEN
DROPPING TO THE MID 20S IN THE GENERAL REGION NEAR CHEMULT. WITH
SEVERAL MORE HOURS OF COOLING TO GO, AND CLOUDS NOT QUITE IN THE
AREA YET, THE CURRENT FROST ADVISORY SEEMS TO BE ON TRACK FOR THE
EAST SIDE. WILL THEREFORE LET THIS RIDE THROUGH THE MORNING.
TEMPERATURES WILL REMAIN MUCH COOLER THAN NORMAL TODAY, AS AMPLE
CLOUDS AND RAIN SHOULD KEEP SOLAR HEATING TO A MINIMUM.
AN UPPER LEVEL LOW, CURRENTLY LOCATED OVER THE SEATTLE AREA, WILL
DROP SOUTH TODAY, AND TAKE POSITION OVER OREGON BY THIS AFTERNOON.
AS IT DROPS SOUTH, A VERY POTENT SHORTWAVE ORBITING THE LOW WILL
PASS OVERHEAD, AND WITH THE LOWERING TEMPERATURES ALOFT, ENOUGH
INSTABILITY AND DYNAMICS SHOULD BE PRESENT TO PRODUCE SHOWERS AND
ISOLATED THUNDERSTORMS OVER THE BULK OF THE FORECAST AREA LATE
THIS MORNING INTO THIS EVENING. WHILE MOST RAINFALL AMOUNTS WILL
BE LIGHT, THERE IS A GOOD CHANCE THAT MANY LOCATIONS COULD SEE
WETTING RAINS. THIS IS PARTICULARLY TRUE EAST OF THE CASCADES,
WHERE FORCING WILL BE STRONGEST DURING THE PEAK OF DAYTIME
HEATING. OVERNIGHT, THE COLD AIR MASS WILL BEGIN TO SETTLE IN.
HOWEVER, THERE SHOULD BE AMPLE CLOUDS REMAINING IN THE AREA, SO
NIGHTTIME LOWS MAY NOT DROP AS LOW AS WOULD BE EXPECTED. HAVE
ADDED PATCHY FROST TO THE FORECAST, BUT GIVEN THE CLOUD COVER, DO
NOT THINK THAT THIS WOULD BE A WIDESPREAD EVENT, SO WILL NOT ISSUE
ANY HEADLINES AT THIS TIME.
THE LOW WILL BEGIN MOVING EAST SATURDAY MORNING, AND GRADUALLY,
SHOWERS AND CLOUDS WILL MOVE OUT OF THE FORECAST AREA AS WELL. EXPECT
THAT THE SKIES WILL BE MOSTLY CLEAR BY SATURDAY NIGHT, AIDED IN PART
TO DEVELOPING OFFSHORE FLOW DRYING OUT THE MID LEVELS. WITH THE COLD
AIR STILL AT THE SURFACE, AND NO CLOUDS TO ACT AS A BLANKET, SUSPECT
THAT THIS WILL BE THE COOLEST NIGHT OF THE WEEK. IN FACT, WIDESPREAD
FROST AND FREEZE IS LIKELY FOR THE EAST SIDE.
THESE COLD TEMPERATURES WILL NOT LAST, HOWEVER, AS UPPER LEVEL
RIDGING WILL BUILD INTO THE AREA, AND THE THERMAL TROUGH WILL RETURN
TO OUR SOUTH. OFFSHORE FLOW SHOULD KEEP THE AREA CLEAR OF CLOUDS,
AND TEMPERATURES WILL RISE TO VALUES AROUND 5 DEGREES ABOVE NORMAL
FOR THIS TIME OF YEAR BY THE MIDDLE OF NEXT WEEK. SEVERAL WAVES WILL
APPROACH THE WEST COAST DURING THIS TIME, BUT THE RIDGE SHOULD KEEP
THE TRACK OF ANY PRECIPITATION MAKING SYSTEMS WELL NORTH OF THE
FORECAST AREA. THEREFORE, FOR THE REMAINDER OF THE FORECAST TERM,
EXPECT GRADUALLY WARMING TEMPERATURES AND DRY CONDITIONS. -BPN
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...
- SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR PZZ376.
$$
AREA FORECAST DISCUSSION
NWS MEDFORD OR
858 AM PDT FRI SEP 4 2015
.DISCUSSION...THE UPPER LOW IS NOW CENTERED OVER WESTERN
WASHINGTON AND WILL CONTINUE TO MOVE SOUTH OVER THE AREA LATE
THIS AFTERNOON. A LINE OF SHOWERS AND ISOLATED THUNDERSTORMS BROKE
OUT IN ADVANCE OF AN SHORTWAVE TROUGH ROTATING AROUND THE UPPER
LOW WHICH IS NOW IN NORTHWEST CAL. SHOWERS AND ISOLATED
THUNDERSTORMS WILL INCREASE OVER TIME AS THE UPPER LOW AND COLD
AIR ALOFT (-25C AT 500MB) MOVES OVERHEAD INCREASING INSTABILITY.
THE LATEST HRRR MODEL RUN SHOWS MOST OF THE SHOWERS AND ISOLATED
THUNDERSTORMS ALONG AND EAST OF THE CASCADES, BUT SUSPECT IT MAY
BE UNDERESTIMATING THE CONVECTIVE ACTIVITY WEST OF THE CASCADES.
THEREFORE WE`LL CONTINUE TO KEEP POPS HIGHER WEST OF THE CASCADES
THIS AFTERNOON. IN ADDITION THERE`S A CHANCE SOME THUNDERSTORMS
COULD PRODUCE GUSTY WINDS AND SMALL HAIL.
THE 12Z NAM AND GFS SHOW THE TROUGH AXIS MOVING EAST OF THE
CASCADES LATE TONIGHT AT WHICH POINT THE BULK OF THE PRECIPITATION
WILL SHIFT INTO LAKE, MODOC AND EASTERN KLAMATH COUNTY. SATURDAY
IS STILL A TRANSITION DAY WITH ANY SHOWERS CONFINED TO EASTERN
LAKE COUNTY IN THE MORNING AND DRY CONDITIONS ELSEWHERE.
-PETRUCELLI
&&
.AVIATION...FOR THE 04/12Z TAF CYCLE...VFR CONDITIONS WILL CONTINUE
FOR MOST TAF SITES EARLY THIS MORNING. CLOUDS AND SHOWERS WILL
INCREASE AND CIGS WILL LOWER THROUGH THIS MORNING, ESPECIALLY EAST
OF THE CASCADES WHERE SHOWERS WILL BE MOST NUMEROUS. THUNDERSTORMS
WILL ALSO BE POSSIBLE THIS AFTERNOON. MVFR CIGS AND VIS ARE EXPECTED
IN HEAVIER SHOWERS. ALSO EXPECT MOUNTAIN OBSCURATIONS, ESPECIALLY
OVER AND EAST OF THE CASCADES. THESE CONDITIONS WILL PERSIST INTO
THIS EVENING. -WRIGHT
&&
.MARINE...UPDATED 230 AM PDT FRIDAY 4 SEPTEMBER 2015...NORTH WINDS
WILL CONTINUE THROUGH THE FORECAST PERIOD. A PERIOD OF SMALL CRAFT
ADVISORY LEVEL WINDS IS EXPECTED THIS AFTERNOON AND EVENING SOUTH OF
CAPE BLANCO. WINDS THEN STRENGTHEN AGAIN SUNDAY AS A THERMAL TROUGH
FORMS OVER NORTHERN CALIFORNIA. GALES WILL BE POSSIBLE OVER THE
SOUTHERN WATERS MONDAY AND TUESDAY. SEAS WILL BE PRIMARILY WIND
DRIVEN THROUGH EARLY NEXT WEEK. -WRIGHT
&&
.PREV DISCUSSION... /ISSUED 639 AM PDT FRI SEP 4 2015/
UPDATE...PUT OUT A QUICK UPDATE JUST NOW TO INCREASE POPS ON THE
EAST SIDE AND ALLOW FOR THUNDERSTORMS OVER ALL AREAS THIS MORNING.
AIRMASS IS ALREADY DESTABILIZING QUICKLY AND WE`VE SEEN SIX
LIGHTNING STRIKES ALONG THE SISKIYOU/MODOC BORDER, AND THIS IS
WITH THE MAJORITY OF THE COLD POOL AND INSTABILITY YET TO COME
TODAY. IT ALSO WOULDN`T BE OUT OF THE QUESTION TO SEE A FEW
SNOWFLAKES OVER LAKE AND MODOC COUNTIES THIS MORNING AS SURFACE
TEMPERATURES ARE NEAR OR BELOW FREEZING. TEMP/DEWPOINT SPREAD ARE
FAIRLY HIGH, THOUGH, SO IT MAY BE JUST VIRGA OUT THERE. -WRIGHT
PREV DISCUSSION... /ISSUED 325 AM PDT FRI SEP 4 2015/
DISCUSSION...TEMPERATURES THIS MORNING HAVE BEEN QUITE COLD
RELATIVE TO NORMAL FOR THIS TIME OF YEAR, WITH TEMPERATURES EVEN
DROPPING TO THE MID 20S IN THE GENERAL REGION NEAR CHEMULT. WITH
SEVERAL MORE HOURS OF COOLING TO GO, AND CLOUDS NOT QUITE IN THE
AREA YET, THE CURRENT FROST ADVISORY SEEMS TO BE ON TRACK FOR THE
EAST SIDE. WILL THEREFORE LET THIS RIDE THROUGH THE MORNING.
TEMPERATURES WILL REMAIN MUCH COOLER THAN NORMAL TODAY, AS AMPLE
CLOUDS AND RAIN SHOULD KEEP SOLAR HEATING TO A MINIMUM.
AN UPPER LEVEL LOW, CURRENTLY LOCATED OVER THE SEATTLE AREA, WILL
DROP SOUTH TODAY, AND TAKE POSITION OVER OREGON BY THIS AFTERNOON.
AS IT DROPS SOUTH, A VERY POTENT SHORTWAVE ORBITING THE LOW WILL
PASS OVERHEAD, AND WITH THE LOWERING TEMPERATURES ALOFT, ENOUGH
INSTABILITY AND DYNAMICS SHOULD BE PRESENT TO PRODUCE SHOWERS AND
ISOLATED THUNDERSTORMS OVER THE BULK OF THE FORECAST AREA LATE
THIS MORNING INTO THIS EVENING. WHILE MOST RAINFALL AMOUNTS WILL
BE LIGHT, THERE IS A GOOD CHANCE THAT MANY LOCATIONS COULD SEE
WETTING RAINS. THIS IS PARTICULARLY TRUE EAST OF THE CASCADES,
WHERE FORCING WILL BE STRONGEST DURING THE PEAK OF DAYTIME
HEATING. OVERNIGHT, THE COLD AIR MASS WILL BEGIN TO SETTLE IN.
HOWEVER, THERE SHOULD BE AMPLE CLOUDS REMAINING IN THE AREA, SO
NIGHTTIME LOWS MAY NOT DROP AS LOW AS WOULD BE EXPECTED. HAVE
ADDED PATCHY FROST TO THE FORECAST, BUT GIVEN THE CLOUD COVER, DO
NOT THINK THAT THIS WOULD BE A WIDESPREAD EVENT, SO WILL NOT ISSUE
ANY HEADLINES AT THIS TIME.
THE LOW WILL BEGIN MOVING EAST SATURDAY MORNING, AND GRADUALLY,
SHOWERS AND CLOUDS WILL MOVE OUT OF THE FORECAST AREA AS WELL. EXPECT
THAT THE SKIES WILL BE MOSTLY CLEAR BY SATURDAY NIGHT, AIDED IN PART
TO DEVELOPING OFFSHORE FLOW DRYING OUT THE MID LEVELS. WITH THE COLD
AIR STILL AT THE SURFACE, AND NO CLOUDS TO ACT AS A BLANKET, SUSPECT
THAT THIS WILL BE THE COOLEST NIGHT OF THE WEEK. IN FACT, WIDESPREAD
FROST AND FREEZE IS LIKELY FOR THE EAST SIDE.
THESE COLD TEMPERATURES WILL NOT LAST, HOWEVER, AS UPPER LEVEL
RIDGING WILL BUILD INTO THE AREA, AND THE THERMAL TROUGH WILL RETURN
TO OUR SOUTH. OFFSHORE FLOW SHOULD KEEP THE AREA CLEAR OF CLOUDS,
AND TEMPERATURES WILL RISE TO VALUES AROUND 5 DEGREES ABOVE NORMAL
FOR THIS TIME OF YEAR BY THE MIDDLE OF NEXT WEEK. SEVERAL WAVES WILL
APPROACH THE WEST COAST DURING THIS TIME, BUT THE RIDGE SHOULD KEEP
THE TRACK OF ANY PRECIPITATION MAKING SYSTEMS WELL NORTH OF THE
FORECAST AREA. THEREFORE, FOR THE REMAINDER OF THE FORECAST TERM,
EXPECT GRADUALLY WARMING TEMPERATURES AND DRY CONDITIONS. -BPN
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR PZZ376.
$$
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
631 PM EDT FRI SEP 4 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 SATURDAY MORNING/...
SAME SCENARIO PLAYING OUT THIS EVENING AS THE LAST SEVERAL...WITH
DIURNALLY FORCED CONVECTION...THIS TIME MAINLY TREKKING EAST TO
WEST...SCATTERED ABOUT THE REGION. THE SHOWERS AND STORMS WILL
GRADUALLY LOSE VIGOR OVER THE NEXT SEVERAL HOURS AS WE LOSE
HEATING. UNTIL THEN...SOME OF THE STRONGER SLOW MOVING STORMS
COULD PRODUCE GUSTY WINDS...DOWNPOURS AND POSSIBLE LOCALIZED
FLOODING.
INTERESTING TO NOTE THE HRRR REALLY LIGHTS THINGS UP AFTER 00Z
OVER THE SOUTH-CENTRAL MOUNTAINS. THIS SEEMS COUNTERINTUITIVE
GIVEN THE WEAK DIURNAL FORCING.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
CONVECTION ONGOING AT THE START OF THE PERIOD MAY BE THE LAST OF
THE RAIN FOR A FEW DAYS. EXPECT SHRA/TSRA TO WANE THROUGH THE
EVENING. THE INTERESTING/CHALLENGING PART OF THIS FORECAST MAY BE
THE CLOUD COVER TONIGHT AND SAT MORNING AND RESULTANT MINS/MAXES.
THE NAM IS PRETTY AGGRESSIVE IN ADVECTING LOW CRUD/STRATUS IN FROM
THE EAST/SOUTHEAST TONIGHT AND PILING IT UP IN THE MOUNTAINS.
HOWEVER...THE GFS IS NOT SO BULLISH ON THE LOW LEVEL MOISTURE. IT
STILL MAKES LOWER CLOUDS /BELOW 8H/ BUT IS MORE NORTHEASTERLY WITH
THE WINDS ON THE SRN PERIPHERY OF THE HIGH. THUS...MORE DRY AIR IS
SEEN ADVECTING INTO THE AREA IN THE GFS SOLUTION. THIS ALLOWS THE
MARITIME AIR/CLOUDS TO DRY OUT QUICKLY WITH MINIMAL MIXING. THE
TROUBLE WITH THE DRIER SOLUTION IS THAT WE HAVE BEEN PRETTY MUGGY
AND THE MDL OMEGA FIELDS DO NOT PORTRAY SOME OVERWHELMING DOWN-
MOTION. IN FACT...THEY ARE PRETTY NEUTRAL. VERY ISOLATED DIURNAL
CONVECTION IS POSSIBLE IN THE FAR WEST/SOUTHWEST ON SAT...BUT THE
PWATS WILL BE MUCH LOWER - ONLY RANGING FROM 1 INCH IN THE NE TO
1.25 IN THE WEST. AT THIS POINT...THE MOST PROBABLE SOLUTION IN
OUR WEAK FLOW IS THAT THE SFC HIGH STAYS UP OVER NEW ENGLAND AND
THE DRY AIR MAKES ONLY SLOW PROGRESS TO MOVE ACROSS THE REGION.
WILL KEEP IT MORE CLOUDY AND COOLER IN THE FIRST PART OF THE DAY
AND KEEP MAXES SHORT OF GFS-MOS GUIDANCE.
&&
.LONG TERM /SATURDAY 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 AMPLYIFYING 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 /22Z FRIDAY THROUGH WEDNESDAY/...
GENERALLY VFR CONDS EXPECTED THROUGH EARLY EVENING HOURS...SAVE
WHERE ISOLATED SHRA/TSRA MAY IMPACT AIRFIELDS...MAINLY ACROSS
SOUTHERN PA. A BRIEF VIS REDUCTION IS POSSIBLE IN A FEW SPOTS FROM
THESE STORMS...MAINLY THRU 05/01Z.
A MOIST SERLY FLOW BEHIND THE COLD FRONT WILL LIKELY PRODUCE SOME
LOW CIGS ACROSS THE MTNS OF CENTRAL PA TONIGHT AND EARLY SAT AM.
SFC HIGH PRESSURE WILL BUILD INTO THE REGION FOR THE WEEKEND.
OUTLOOK...
SAT...AM LOW CIGS POSS...MAINLY KBFD/KJST.
SUN-TUE...PATCHY AM FOG POSS...MAINLY KBFD/KIPT.
WED...COLD FROPA WITH SCT SHRA/TSRA.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE/GARTNER
NEAR TERM...LA CORTE/GARTNER
SHORT TERM...DANGELO/GARTNER
LONG TERM...LAMBERT
AVIATION...GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
307 PM EDT FRI SEP 4 2015
.SYNOPSIS...
ABOVE NORMAL TEMPERATURES WILL CONTINUE INTO NEXT WEEK WITH
GRADUALLY DECREASING HUMIDITY LEVELS. ISOLATED SHOWERS AND
THUNDERSTORMS ARE POSSIBLE INTO EARLY THIS EVENING. HIGH PRESSURE
WILL ENSURE FAIR AND DRY WEATHER FOR LABOR DAY WEEKEND.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
ISOLATED SHOWERS AND THUNDERSTORMS AGAIN POPPING THIS AFTN AS
EXPECTED...MAINLY ACROSS SRN PA. THIS WILL CONTINUE FOR THE NEXT
SEVERAL HOURS WITH ANY SLOW MOVING STORMS PRODUCING BRIEF HEAVY
DOWNPOURS.
GUIDANCE INCLUDING LATEST HRRR IMAGERY SHOWS A CONVERGENCE OF
ACTIVITY THROUGH THE LOWER SUSQ VALLEY SOUTH CENTRAL MTNS AS WEAK
BACKDOOR COLD FRONT DROPS SOUTH...AND EASTERLY FLOW ON SRN END OF
SFC HIGH CONCENTRATES MOISTURE WESTWARD INTO THE REGION.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM SATURDAY/...
CONVECTION ONGOING AT THE START OF THE PERIOD MAY BE THE LAST OF
THE RAIN FOR A FEW DAYS. EXPECT SHRA/TSRA TO WANE THROUGH THE
EVENING. THE INTERESTING/CHALLENGING PART OF THIS FORECAST MAY BE
THE CLOUD COVER TONIGHT AND SAT MORNING AND RESULTANT MINS/MAXES.
THE NAM IS PRETTY AGGRESSIVE IN ADVECTING LOW CRUD/STRATUS IN FROM
THE EAST/SOUTHEAST TONIGHT AND PILING IT UP IN THE MOUNTAINS.
HOWEVER...THE GFS IS NOT SO BULLISH ON THE LOW LEVEL MOISTURE. IT
STILL MAKES LOWER CLOUDS /BELOW 8H/ BUT IS MORE NORTHEASTERLY WITH
THE WINDS ON THE SRN PERIPHERY OF THE HIGH. THUS...MORE DRY AIR IS
SEEN ADVECTING INTO THE AREA IN THE GFS SOLUTION. THIS ALLOWS THE
MARITIME AIR/CLOUDS TO DRY OUT QUICKLY WITH MINIMAL MIXING. THE
TROUBLE WITH THE DRIER SOLUTION IS THAT WE HAVE BEEN PRETTY MUGGY
AND THE MDL OMEGA FIELDS DO NOT PORTRAY SOME OVERWHELMING DOWN-
MOTION. IN FACT...THEY ARE PRETTY NEUTRAL. VERY ISOLATED DIURNAL
CONVECTION IS POSSIBLE IN THE FAR WEST/SOUTHWEST ON SAT...BUT THE
PWATS WILL BE MUCH LOWER - ONLY RANGING FROM 1 INCH IN THE NE TO
1.25 IN THE WEST. AT THIS POINT...THE MOST PROBABLE SOLUTION IN
OUR WEAK FLOW IS THAT THE SFC HIGH STAYS UP OVER NEW ENGLAND AND
THE DRY AIR MAKES ONLY SLOW PROGRESS TO MOVE ACROSS THE REGION.
WILL KEEP IT MORE CLOUDY AND COOLER IN THE FIRST PART OF THE DAY
AND KEEP MAXES SHORT OF GFS-MOS GUIDANCE.
&&
.LONG TERM /SATURDAY 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 AMPLYIFYING 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 /19Z FRIDAY THROUGH WEDNESDAY/...
GENERALLY VFR CONDS EXPECTED THROUGH EARLY EVENING HOURS...SAVE
WHERE ISOLATED SHRA/TSRA MAY IMPACT AIRFIELDS...MAINLY ACROSS
SOUTHERN PA. A BRIEF VIS REDUCTION IS POSSIBLE IN A FEW SPOTS FROM
THESE STORMS...MAINLY THRU 05/01Z.
A MOIST SERLY FLOW BEHIND THE COLD FRONT WILL LIKELY PRODUCE SOME
LOW CIGS ACROSS THE MTNS OF CENTRAL PA TONIGHT AND EARLY SAT AM.
SFC HIGH PRESSURE WILL BUILD INTO THE REGION FOR THE WEEKEND.
OUTLOOK...
SAT...AM LOW CIGS POSS...MAINLY KBFD/KJST.
SUN-TUE...PATCHY AM FOG POSS...MAINLY KBFD/KIPT.
WED...COLD FROPA WITH SCT SHRA/TSRA.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/GARTNER
NEAR TERM...GARTNER
SHORT TERM...DANGELO/GARTNER
LONG TERM...LAMBERT
AVIATION...GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
245 PM EDT FRI SEP 4 2015
.SYNOPSIS...
ABOVE NORMAL TEMPERATURES WILL CONTINUE INTO NEXT WEEK WITH
GRADUALLY DECREASING HUMIDITY LEVELS. ISOLATED SHOWERS AND
THUNDERSTORMS ARE POSSIBLE INTO EARLY THIS EVENING. HIGH PRESSURE
WILL ENSURE FAIR AND DRY WEATHER FOR LABOR DAY WEEKEND.
&&
.NEAR TERM /UNTIL 9 PM THIS EVENING/...
ISOLATED SHOWERS AND THUNDERSTORMS AGAIN POPPING THIS AFTN AS
EXPECTED...MAINLY ACROSS SRN PA. THIS WILL CONTINUE FOR THE NEXT
SEVERAL HOURS WITH ANY SLOW MOVING STORMS PRODUCING BRIEF HEAVY
DOWNPOURS.
GUIDANCE INCLUDING LATEST HRRR IMAGERY SHOWS A CONVERGENCE OF
ACTIVITY THROUGH THE LOWER SUSQ VALLEY SOUTH CENTRAL MTNS AS WEAK
BACKDOOR COLD FRONT DROPS SOUTH...AND EASTERLY FLOW ON SRN END OF
SFC HIGH CONCENTRATES MOISTURE WESTWARD INTO THE REGION.
&&
.SHORT TERM /9 PM THIS EVENING THROUGH 6 PM SATURDAY/...
CONVECTION ONGOING AT THE START OF THE PERIOD MAY BE THE LAST OF
THE RAIN FOR A FEW DAYS. EXPECT SHRA/TSRA TO WANE THROUGH THE
EVENING. THE INTERESTING/CHALLENGING PART OF THIS FORECAST MAY BE
THE CLOUD COVER TONIGHT AND SAT MORNING AND RESULTANT MINS/MAXES.
THE NAM IS PRETTY AGGRESSIVE IN ADVECTING LOW CRUD/STRATUS IN FROM
THE EAST/SOUTHEAST TONIGHT AND PILING IT UP IN THE MOUNTAINS.
HOWEVER...THE GFS IS NOT SO BULLISH ON THE LOW LEVEL MOISTURE. IT
STILL MAKES LOWER CLOUDS /BELOW 8H/ BUT IS MORE NORTHEASTERLY WITH
THE WINDS ON THE SRN PERIPHERY OF THE HIGH. THUS...MORE DRY AIR IS
SEEN ADVECTING INTO THE AREA IN THE GFS SOLUTION. THIS ALLOWS THE
MARITIME AIR/CLOUDS TO DRY OUT QUICKLY WITH MINIMAL MIXING. THE
TROUBLE WITH THE DRIER SOLUTION IS THAT WE HAVE BEEN PRETTY MUGGY
AND THE MDL OMEGA FIELDS DO NOT PORTRAY SOME OVERWHELMING DOWN-
MOTION. IN FACT...THEY ARE PRETTY NEUTRAL. VERY ISOLATED DIURNAL
CONVECTION IS POSSIBLE IN THE FAR WEST/SOUTHWEST ON SAT...BUT THE
PWATS WILL BE MUCH LOWER - ONLY RANGING FROM 1 INCH IN THE NE TO
1.25 IN THE WEST. AT THIS POINT...THE MOST PROBABLE SOLUTION IN
OUR WEAK FLOW IS THAT THE SFC HIGH STAYS UP OVER NEW ENGLAND AND
THE DRY AIR MAKES ONLY SLOW PROGRESS TO MOVE ACROSS THE REGION.
WILL KEEP IT MORE CLOUDY AND COOLER IN THE FIRST PART OF THE DAY
AND KEEP MAXES SHORT OF GFS-MOS GUIDANCE.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
NOT MUCH TO CHANGE IN A SLOWLY EVOLVING EXTENDED FORECAST. HIGH
PRESSURE SHOULD MAINTAIN DRY WEATHER SUNDAY-MONDAY. LEAD COLD
FRONT ADVANCING EWD FROM THE GREAT LAKES/MIDWEST AND POTENTIAL
ONSHORE FLOW MSTR MAY IMPACT THE FCST BY TUESDAY WITH SCT TSTMS
POSS...BUT A CONSENSUS SOLUTION HOLDS BACK HIGHER POPS UNTIL WED
OR MAYBE EVEN THU IN ASSOCIATION WITH A STRONGER SHORTWAVE/SFC
COLD FRONT. SO TIMING DIFFS WILL NEED TO BE RESOLVED AS THE RIDGE
SLOWLY BREAKS DOWN.
THE GLOBAL NUMERICAL MODELS/ENSEMBLES ARE COMING INTO BETTER
AGREEMENT ON A PATTERN CHANGE DURING THE SECOND HALF OF NEXT WEEK
WITH A SHUFFLING OF THE LONGWAVE FLOW ALLOWING EWD PROGRESSION OF
THE WESTERN TROUGH INTO THE CENTRAL STATES AND RECENT RIDGE OVER
THE EASTERN UNITED STATES OFF THE COAST INTO THE WRN ATLC. THIS
SHOULD EVENTUALLY BRING AN END TO THE RECENT HOT/DRY SPELL. A
RETURN TO SEASONAL TEMPERATURES AND MORE ACTIVE PCPN PATTERN
SEEMS PROBABLE BY NEXT WEEKEND IN THE NEW FLOW REGIME.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
GENERALLY VFR CONDS EXPECTED THROUGH EARLY EVENING HOURS...SAVE
WHERE ISOLATED SHRA/TSRA MAY IMPACT AIRFIELDS...MAINLY ACROSS
SOUTHERN PA. A BRIEF VIS REDUCTION IS POSSIBLE IN A FEW SPOTS FROM
THESE STORMS...MAINLY THRU 05/01Z.
A MOIST SERLY FLOW BEHIND THE COLD FRONT WILL LIKELY PRODUCE SOME
LOW CIGS ACROSS THE MTNS OF CENTRAL PA TONIGHT AND EARLY SAT AM.
SFC HIGH PRESSURE WILL BUILD INTO THE REGION FOR THE WEEKEND.
OUTLOOK...
SAT...AM LOW CIGS POSS...MAINLY KBFD/KJST.
SUN-TUE...PATCHY AM FOG POSS...MAINLY KBFD/KIPT.
WED...COLD FROPA WITH SCT SHRA/TSRA.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/GARTNER
NEAR TERM...GARTNER
SHORT TERM...DANGELO/GARTNER
LONG TERM...RXR/STEINBUGL
AVIATION...GARTNER
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1023 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 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1018 PM CDT SAT SEP 5 2015
THE LLJ IS BEGINNING TO RAMP UP AS WE APPROACH MIDNIGHT...AND
HAVE AGAIN PUT IN LLWS. FOCUS OF THE LLJ COULD DRIVE A FEW
ADDITIONAL SHOWERS LATE TONIGHT...BUT ELEVATED INSTABILITY LOOKS
MEAGER. GIVEN ISOLATED NATURE...WILL LEAVE OUT OF TAF ATTM.
FOR SUNDAY...HIGH RES MODELS AGAIN SHOW SCATTERED SHOWERS LIFTING
INTO THE TRI-STATE AREA AROUND MID-DAY. THIS MAY STABILIZE THE
AREA DIRECTLY AHEAD OF THE ADVANCING FRONTAL BOUNDARY...ALLOWING
BETTER FOCUS TO DEVELOP ALONG A WEAK PRE-FRONTAL BOUNDARY FURTHER
SE IN IOWA/NEBRASKA. AGAIN...COVERAGE OF STORM ACTIVITY MAY BE TOO
LIMITED TO INCLUDE FOR ANY PREVAILING CONDITION IN TAFS.
OTHER CONCERN WOULD BE A BIT OF MVFR STRATUS BEHIND THE FRONT AS
IT ARRIVES LATER IN THE AFTERNOON. WILL INCLUDE A SCATTERED DECK
AROUND 2500 FT AGL TO HINT AT THE POTENTIAL.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...
LONG TERM...
AVIATION...DUX
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
629 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 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 612 PM CDT SAT SEP 5 2015
SHORTWAVE ENERGY LIFTING INTO THE NORTHERN PLAINS HAS CHANGED THE
FOCUS FOR CONVECTION INTO THE EVENING OVERNIGHT HOURS. THE LLJ
WILL EVENTUALLY RAMP UP THROUGH THE EVENING...AND HAVE AGAIN PUT
IN LLWS. FOCUS OF THE LLJ COULD DRIVE A FEW ADDITIONAL SHOWERS
LATE TONIGHT...BUT ELEVATED INSTABILITY LOOKS MEAGER.
FOR SUNDAY...HIGH RES MODELS AGAIN SHOW SCATTERED SHOWERS LIFTING
INTO THE TRI-STATE AREA AROUND MID-DAY. THIS MAY STABILIZE THE
AREA DIRECTLY AHEAD OF THE ADVANCING FRONTAL BOUNDARY...ALLOWING
BETTER FOCUS TO DEVELOP ALONG A WEAK PRE-FRONTAL BOUNDARY FURTHER
SE IN IOWA/NEBRASKA. FOR NOW...WILL ONLY INCLUDE A VCSH AT
FSD/SUX FOR THE AFTN.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...
LONG TERM...
AVIATION...DUX
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1246 PM CDT FRI SEP 4 2015
.DISCUSSION...SEE 18Z AVIATION DISCUSSION.
&&
.AVIATION...HAVE VCSH AND/OR TEMPO SHRA IN THE TERMINALS FOR ON-
GOING CONVECTION AT ALL BUT KLRD...BASED ON RADAR AND HRRR MODEL
DATA. EXPECT CONVECTION TO BE GONE BY 05/000Z IF NOT EARLIER.
THINK CONVECTION WILL MAINLY BE SHOWERS SO DID NOT MENTION THUNDER
(WILL HAVE TO MONITOR RADAR THOUGH). DID NOT INCLUDE CONVECTION AT
KLRD AS THINK MOST PRECIP SHOULD STAY EAST OF TERMINAL. OUTSIDE OF
CONVECTION...VFR THROUGH 05/10Z THEN COULD EITHER SEE SOME MVFR
CIGS AT KLRD AND VSBYS AT KALI/KVCT BETWEEN 10Z-14Z (COULD EVEN
HAVE TEMPO IFR BR AT KALI/KVCT). SHOULD BE LESS CONVECTION ON
SATURDAY BUT DID HAVE A VCSH AT KVCT WHERE MOISTURE IS BETTER AND
CONVECTION FROM GULFMEX HAS THE BEST CHANCE OF REACHING A TERMINAL
(CONFIDENCE TOO LOW FOR A PROB30). WINDS GENERALLY SSE AND LESS
THAN 11 KNOTS BUT COULD BE GUSTY THIS AFTERNOON KCRP...KALI AND
KLRD TERMINALS.
&&
.PREV DISCUSSION... /ISSUED 1001 AM CDT FRI SEP 4 2015/
DISCUSSION...MAIN CHANGE WAS TO CHANGE MENTION OF RAIN FROM
PROBABILITY TO COVERAGE (E.G. CHANCE TO SCATTERED). FEW MINOR
ADJUSTMENTS TO WINDS. TEMPERATURES LOOK FINE. CRP SOUNDING
SHOWING PWATS NEAR 2 INCHES SO ISOLATED TO SCATTERED LOOKS
REASONABLE AND NO EXPECT LOWER COVERAGE LATER THIS AFTERNOON AS
MIXING PRECLUDES DEEP CONVECTION. UPDATED PRODUCTS OUT.
PREV DISCUSSION... /ISSUED 641 AM CDT FRI SEP 4 2015/
DISCUSSION...UPDATED FOR 12Z AVIATION.
AVIATION...MVFR CIGS/VSBYS WILL STILL BE A POSSIBILITY AT
LRD/ALI/VCT EARLY THIS MORNING...BEFORE RETURNING TO VFR LEVELS
BY 15Z. ISOLATED TO SCATTERED SHOWERS AND STORMS MAY OCCUR TODAY
ACROSS SOUTH TEXAS...AND HAVE INCLUDED ONLY VCSH REMARKS AT
ALI/VCT/CRP FOR NOW. ANY CONVECTION THAT DEVELOPS SHOULD DISSIPATE
WITH THE LOSS OF DAYTIME HEATING. WINDS WILL BE MOSTLY OUT OF THE
SSE AND SE TODAY WITH A FEW GUSTS AROUND 20 KNOTS DURING THE
AFTERNOON HOURS. PATCHY FOG MAY DEVELOP LATE TONIGHT INTO EARLY
SATURDAY MORNING...BUT CONFIDENCE IS NOT GREAT ENOUGH TO MENTION
IN THE FORECAST.
PREV DISCUSSION... /ISSUED 346 AM CDT FRI SEP 4 2015/
SHORT TERM (TODAY THROUGH SATURDAY)...DESPITE UPPER LEVEL RIDGE
BUILDING OVER THE AREA...LOW CHANCES FOR SHOWERS AND A FEW STORMS
WILL EXIST DURING THE SHORT TERM. MOISTURE WILL BE SUFFICIENT
TODAY WITH PW VALUES AROUND 1.9 TO 2.0 INCHES. ISOLATED CONVECTION
HAS ALL READY DEVELOPED EARLY THIS MORNING OVER THE GULF WATERS
INTO THE NORTHERN COASTAL BEND. ADDITIONAL ACTIVITY IS EXPECTED IS
EXPECTED LATER THIS MORNING...AND THEN SPREAD INLAND WITH THE SEA
BREEZE. SHOWERS AND STORMS SHOULD BE MOSTLY DIURNALLY DRIVEN AND
THEN DISSIPATE WITH THE LOSS OF DAYTIME HEATING THIS EVENING.
TEMPERATURES TODAY WILL BE SLIGHTLY ABOVE NORMAL FOR THIS TIME OF
YEAR...WITH HIGHS AROUND 100 OVER THE RIO GRANDE PLAINS TO LOWER
90S ACROSS THE VICTORIA CROSSROADS. SIMILAR TO THE LAST FEW
DAYS...CONVECTION MAY REDEVELOP LATE IN THE NIGHT OVER THE GULF
WATERS AND MOVE INLAND DURING THE MORNING/EARLY AFTERNOON HOURS.
VERY WARM CONDITIONS WILL BE COMMON ON SATURDAY WITH HIGHS IN THE
LOWER 100S OUT WEST AND LOW/MID 90S ACROSS THE EAST.
LONG TERM (SATURDAY NIGHT THROUGH THURSDAY)...MIDLEVEL RIDGE BUILDS
IN FROM THE WEST WITH LESS MOISTURE AVAILABILITY FOR THE END OF THE
WEEKEND. THE RIDGE FLATTENS AND SHIFTS SOUTHWEST EARLY NEXT WEEK
UNDER A SOUTHWARD PROGRESSING TROUGH MOVING ACROSS THE CENTRAL
PLAINS...AND FROM A DEVELOPING CUT OFF LOW ACROSS THE SOUTHEASTERN
STATES RETROGRADING INTO THE WESTERN GULF. A SLIGHTLY WEAKENED CAP
AND MOISTURE INCREASING ACROSS THE EASTERN HALF OF THE CWA SHOULD
LEAD TO AT LEAST ISOLATED ACTIVITY DEVELOPMENT MONDAY THROUGH
THURSDAY IN THE TYPICAL SUMMER PATTERN WITH NOCTURNAL GULF ACTIVITY
MOVING INLAND AS THE DAY PROGRESSES. OVERALL...MOST LOCATIONS SHOULD
REMAIN DRY. ANY SHOWER ACTIVITY IS EXPECTED TO WANE DURING THE
EVENING HOURS. AS FOR TEMPERATURES...SLIGHTLY ABOVE NORMAL CAN BE
EXPECTED...WITH HIGHS NEAR THE MID 90S ACROSS THE EAST...TO NEAR 100
DEGREES OVER THE RIO GRANDE PLAINS.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 93 78 94 77 95 / 30 10 20 10 10
VICTORIA 92 75 94 75 96 / 40 10 20 10 10
LAREDO 99 77 102 77 102 / 10 10 10 10 0
ALICE 96 75 98 75 99 / 30 10 10 10 10
ROCKPORT 90 79 91 79 91 / 40 20 20 10 10
COTULLA 99 75 101 76 102 / 10 10 10 10 0
KINGSVILLE 95 77 96 76 97 / 30 10 10 10 10
NAVY CORPUS 89 80 90 79 91 / 30 20 20 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
GW/86...AVIATION
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1059 PM CDT SAT SEP 5 2015
UPDATED AVIATION PORTION FOR 06Z TAF 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 06Z TAF ISSUANCE
ISSUED AT 1053 PM CDT SAT SEP 5 2015
ALTHOUGH A FEW SHOWERS OR TSTMS MAY MAKE THEIR WAY INTO NC WI
OVERNIGHT...SUSPECT THAT THE BEST PCPN CHANCES WILL OCCUR
SUNDAY EVG WITH THE APPROACHING COLD FRONT AND A SHORT-WAVE
TROF...SO WILL FOCUS ON THAT PERIOD...AND ONLY CARRY TEMPO
GROUPS FOR TSTMS AT RHI/AUW/CWA FROM 02Z-06Z/MON.
THINK THAT FOG TONIGHT WILL BE PATCHY AND MAINLY MVFR/IFR...AS
BOUNDARY LAYER FLOW INCREASES TO 25 KTS. THE EXCEPTION WILL BE
ALONG THE LKSHR...WHERE DENSE MARINE FOG WILL CONTINUE.
HAVE ADDED A MENTION OF LLWS FOR THE EASTERN TAF SITES SUN
EVG...AS LLVL WINDS INCREASE TO 35 KTS.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......RDM
AVIATION.......KIECKBUSCH
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
622 PM CDT SAT SEP 5 2015
UPDATED AVIATION PORTION FOR 00Z TAF 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 00Z TAF ISSUANCE
ISSUED AT 617 PM CDT SAT SEP 5 2015
PREVIOUS FORECAST LARGELY APPEARS ON TRACK. MADE TWEAKS IN THE
NEAR TERM TO ACCOUNT FOR CURRENT OBSERVATIONS AND SATELLITE TRENDS
IN CLOUDS. AT THE END OF THE PERIOD...BEGAN TO INTRODUCE RAIN
CHANCES AHEAD OF ONCOMING COLD FRONT. WENT WITH A TEMPO IN RHI TO
REFLECT HIGHER CONFIDENCE IN REACHING THAT SITE THAN THE CENTRAL
WISCONSIN DUO...WHICH HAVE ONLY PROB30 AT THIS TIME...AS CERTAINTY
THAT RAIN WILL BE SEEN AT THOSE SITES IS LOWER THAN RHI. FUTURE
FORECAST CYCLES WILL REFINE AS THE MORE LIKELY TIMEFRAME FOR RAIN
AT AUW AND CWA COMES INTO THE FORECAST PERIOD.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......RDM
AVIATION.......LUCHS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
609 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 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 609 PM CDT SAT SEP 5 2015
A SMALL POTENTIAL FOR SHOWERS TO OCCUR OVERNIGHT AT BOTH SITES.
THE 05.18Z NAM AND 05.21Z RAP BOTH SHOW SOME WEAK MOISTURE
TRANSPORT INTO THE AREA WITH SOME ELEVATED INSTABILITY IN THE
FORECAST SOUNDINGS. THIS COULD BE ENOUGH TO KICK OFF SOME
SCATTERED ACTIVITY...BUT CONFIDENCE ON THIS IS NOT HIGH ENOUGH TO
INCLUDE IN THE FORECAST AT THIS TIME. ALSO THE POTENTIAL FOR LOW
LEVEL WIND SHEAR OVERNIGHT AS WINDS BETWEEN 1500 AND 2000 FEET
INCREASE TO 35 TO 40 KNOTS. WITH SURFACE WINDS EXPECTED TO STAY UP
SOME OVERNIGHT...THIS LOOKS TO BE JUST UNDER THE 30 KNOT CRITERIA
FOR WIND SHEAR. THE COLD FRONT OVER THE DAKOTAS AND NEBRASKA WILL
MAKE STEADY EASTWARD PROGRESS AND SHOULD BE APPROACHING THE AREA
BY MID TO LATE SUNDAY AFTERNOON. THE 05.18Z CR-NAM NEST ALONG WITH
THE 05.12Z HI-RES ARW AND NMM ALL DEVELOP CONVECTION ALONG THE
FRONT WITH SOME SLIGHT DIFFERENCES IN TIMING. THE HI-RES ARW
LOOKS TO BE THE QUICKEST WITH IT COMING INTO KRST AROUND 21Z AND
KLSE BETWEEN 22Z AND 23Z WHILE THE CR-NAM NEST AND HI-RES NMM ARE
AN HOUR OR TWO SLOWER. FOR NOW...WILL INTRODUCE A VCTS BASED ON
THE QUICKER TIMING OF THE HI-RES ARW.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
604 PM CDT FRI SEP 4 2015
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 343 PM CDT FRI SEP 4 2015
A WARM FRONT...SITUATED NEAR THE MISSISSIPPI RIVER WILL
GRADUALLY LIFT NORTHEAST LATE THIS AFTERNOON THROUGH TONIGHT.
ISOLATED SHOWERS AND A FEW THUNDERSTORMS ARE POSSIBLE ALONG THIS
FRONT...MAINLY THROUGH 7 PM. WITH ONLY WEAK SHEAR IN
PLACE...SEVERE WEATHER IS NOT EXPECTED.
A WEAK SHORTWAVE WAS MOVING EAST ACROSS SOUTHWEST MINNESOTA/WESTERN
IOWA THIS AFTERNOON PRODUCING A FEW SHOWERS AND ISOLATED
THUNDERSTORMS. THIS WAVE IS EXPECTED TO PUSH EAST ACROSS THE
FORECAST AREA TONIGHT BRINGING VERY SLIGHT CHANCES FOR SHOWERS AND
POSSIBLY A THUNDERSTORM. LOOKING AT FORECAST SOUNDINGS ACROSS THE
AREA TONIGHT THEY ARE SHOWING DRY AIR FROM JUST ABOVE THE SURFACE
THROUGH AROUND 11KFT FT. AIR PARCELS WOULD HAVE TO BE LIFTED FROM
THIS LEVEL TO GET CONVECTION TO GO. BECAUSE OF THIS...THERE IS
VERY LIMITED CAPE TO WORK WITH. THE MOST LIKELY OUTCOME TONIGHT
WILL BE SOME ALTOCUMULUS CASTELLANUS. THE CONVECTIVE ALLOWING
MODELS CONTINUE TO GENERATE SCATTERED SIMULATED RADAR RETURNS
TONIGHT SO WILL CONTINUE WITH A SLIGHT CHANCE FOR SHOWERS AND
STORMS ACROSS MUCH OF THE FORECAST AREA OVERNIGHT. THE WARM FRONT
WILL LIFT TO THE NORTHEAST OVERNIGHT INTO SATURDAY MORNING. WARM
SOUTHERLY FLOW WILL BE THE RULE ON SATURDAY ACROSS THE FORECAST
AREA WITH HIGHS CLIMBING INTO THE MID TO UPPER 80S. A FEW
MISSISSIPPI RIVER VALLEY LOCATIONS COULD REACH THE 90 TO 93 DEGREE
MARK.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 343 PM CDT FRI SEP 4 2015
UPPER LEVEL RIDGE AXIS STARTS TO EDGE EAST SATURDAY NIGHT INTO
SUNDAY AS FLOW ALOFT STARTS TO TRANSITION TO SOUTHWEST AS A TROUGH
EDGES EAST ACROSS THE WESTERN CONUS. AN EMBEDDED SHORTWAVE SLIDES
ACROSS MINNESOTA SATURDAY NIGHT INTO SUNDAY MORNING AND COULD JUST
BRUSH NORTHWEST SECTIONS OF THE FORECAST AREA WITH A COUPLE OF
SHOWERS AND THUNDERSTORMS . OTHERWISE THE PRESSURE GRADIENT WILL
CONTINUE TO TIGHTEN ACROSS THE REGION ON SUNDAY AS A COLD FRONT
APPROACHES. VERY WARM AIR AND DEEP MIXING AHEAD OF THE FRONT WILL
ALLOW TEMPERATURES TO SOAR INTO THE UPPER 80S TO LOWER 90S. A FEW
MID 90S ARE POSSIBLE ACROSS PORTIONS OF SOUTHWEST WISCONSIN. HEAT
INDEX VALUES LOOK TO CLIMB INTO THE MID TO UPPER 90S DURING THE
AFTERNOON HOURS...ESPECIALLY ALONG THE MISSISSIPPI RIVER AND
WISCONSIN RIVER VALLEYS...INTO CENTRAL WISCONSIN. SHOWERS AND STORMS
ARE EXPECTED TO DEVELOP ALONG THE COLD FRONT LATE SUNDAY AFTERNOON
ACROSS NORTHEAST IOWA....SOUTHEAST MINNESOTA AND NORTHWEST
WISCONSIN. 0-1KM MUCAPE VALUES LOOK TO CLIMB INTO THE 1200 TO 18000
J/KG RANGE WEST OF THE MISSISSIPPI RIVER. 0-3 KM BULK SHEAR
VALUES ARE ONLY EXPECTED TO BE IN THE 15 TO 20 KT RANGE. GIVEN THE
CAPE VALUES WE CANNOT RULE OUT A FEW STRONG TO POSSIBLY SEVERE
STORMS WITH THE MAIN THREATS OF STRONG WIND GUSTS...AT LEAST FROM
LATE AFTERNOON INTO EARLY EVENING BEFORE THE CAPE STARTS TO WANE.
THE FRONT WILL PUSH EAST ACROSS THE FORECAST AREA DURING THE
OVERNIGHT HOURS WITH SHOWERS AND STORMS EXPECTED ALONG IT. THE
STORMS WILL PROBABLY BE ON A WEAKENING TREND AS THEY MAKE IT INTO
WESTERN AND CENTRAL WISCONSIN. ANOTHER ITEM WORTH NOTING IS THAT
THE JET POSITION RELATIVE TO THE COLD FRONT. THE 300 MB JET IS
LAGGING BEHIND THE FRONT AND ORIENTED PARALLEL WHICH ISN/T
FAVORABLE FOR DEEP LIFT. MUCH MORE COMFORTABLE
TEMPERATURES/DEWPOINTS MOVE INTO THE REGION IN THE WAKE OF THE
FRONT FOR MONDAY INTO TUESDAY. THERE ARE CHANCES FOR SHOWERS AND
STORMS AGAIN ON TUESDAY AS THE FRONT HANGS UP ACROSS CENTRAL IOWA
INTO NORTHERN ILLINOIS WITH SOME MOISTURE POSSIBLY OVERRUNNING
THE FRONT. WILL HAVE TO KEEP A CLOSE EYE ON EXACTLY WHERE THIS
FRONT DECIDES TO SET UP. THERE ARE LOW CHANCES FOR SHOWERS AND
STORM FROM WEDNESDAY INTO FRIDAY BUT FORECAST CONFIDENCE IS LOW AT
THIS TIME...SO LEANED TOWARD A MODEL CONSENSUS BLEND.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 604 PM CDT FRI SEP 4 2015
BAND OF APPROACHING SHOWERS OR SPRINKLES FROM NORTH CENTRAL IOWA
LOOKS TO BE FALLING OUT OF A MID LEVEL DECK. THESE SHOWERS ARE
ASSOCIATED WITH A SHORT WAVE TROUGH THAT EXTENDS FROM EASTERN
NORTH DAKOTA INTO NORTHWEST IOWA. THE 04.21Z RAP CONTINUES TO MOVE
THIS SHORT WAVE TROUGH SLOWLY TO THE NORTHEAST THIS EVENING WHICH
SHOULD ALLOW THE CLOUDS TO SPREAD OVER BOTH SITES FOR A VFR
CEILING. THE 04.12Z HI-RES NMM PROBABLY HAS THE BEST HANDLE ON THE
SHOWERS AND SUGGESTS THAT THE SOUTHERN END OF THESE MAY FALL APART
AS THE BEST FORCING REMAINS WELL TO THE NORTH CLOSER TO THE
STRONGER PORTION OF THE SHORT WAVE TROUGH OVER NORTH DAKOTA. WITH
THIS SCENARIO SOME SPRINKLES WOULD BE ABOUT ALL THAT WOULD BE
POSSIBLE THIS EVENING. FOR NOW...WILL NOT INCLUDE ANY MENTION OF
SHOWERS...BUT WILL MONITOR RADAR TRENDS AS KRST COULD POSSIBLY SEE
SOMETHING IF THESE HOLD TOGETHER. NOT EXPECTING ANY FOG TO FORM
OVERNIGHT WITH THE CLOUDS OVER THE AREA AND DECENT MIXING EXPECTED
IN THE LOW LEVELS. SOME GUSTY SOUTH WINDS EXPECTED SATURDAY AT
KRST AS THE GRADIENT BECOMES A LITTLE TIGHTER AND WITH A WELL
MIXED BOUNDARY LAYER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...04
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
444 PM MDT FRI SEP 4 2015
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 348 PM MDT FRI SEP 4 2015
ANOTHER ROUND OF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL
MOVE ACROSS MUCH OF THE FORECAST AREA THIS AFTERNOON AND EVENING.
GUSTY WINDS WILL ACCOMPANY SOME SHOWERS AND THUNDERSTORMS. WINDS
TO NEAR 50 MPH HAVE ALREADY BEEN MEASURED AT LARAMIE AND NEAR
BAGGS WYOMING. GUSTY WINDS WILL BE THE MAIN CONCERN OVER THE NEXT
FEW HOURS...OTHERWISE SEVERE STORMS ARE NOT A THREAT TODAY.
SOUTHWEST FLOW ALOFT WILL REMAIN IN PLACE SATURDAY WITH MORE
CHANCES FOR SHOWERS AND THUNDERSTORMS. THE OVERALL COVERAGE WILL
BE MINIMAL AND NOT EXPECTING SEVERE STORMS BUT A FEW STRONG WIND
GUSTS WILL ONCE AGAIN BE POSSIBLE IN THE AFTERNOON.
CHANGES WILL TAKE PLACE SATURDAY NIGHT INTO SUNDAY AS A
RELATIVELY STRONG DISTURBANCE LIFTS NORTHEAST ACROSS MONTANA AND
INTO SOUTHERN CANADA. AN ASSOCIATED COLD FRONT WILL MOVE ACROSS
THE FORECAST AREA LATE SATURDAY NIGHT...BRINGING COOLER
TEMPERATURES AND WINDY CONDITIONS SUNDAY.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 324 PM MDT FRI SEP 4 2015
MONDAY-MONDAY NIGHT:
LATEST WATER VAPOR LOOP WAS SHOWING THE UPPER LEVEL TROF SPINNING
IN THE NORTHWEST U.S. MEANWHILE...ANOTHER SHORTWAVE WAS DIVING
SOUTHEAST ALONG THE COAST OF BRITISH COLUMBIA. THIS FEATURE MAY
SERVE AS A KICKER TO PUSH THE TROF NORTHEAST TOWARDS CENTRAL
CANADA EARLY NEXT WEEK. AS A RESULT...WE MAY SEE THE EFFECTS OF
THE SECONDARY SHORTWAVE MOVE THROUGH MONTANA AND NORTHERN WYOMING
MONDAY. THIS MAY RESULT IN SOME GUSTY WEST WINDS AHEAD OF THE
BOUNDARY ACROSS AREAS MAINLY ALONG AND WEST OF THE LARAMIE RANGE
ON MONDAY. MOISTURE WILL BE QUITE LIMITED AS THIS UPPER LEVEL WAVE
PASSES THROUGH WITH THE BULK OF THE MOISTURE EXPECTED TO BE IN THE
NEBRASKA PANHANDLE. WE MAY SEE A FEW SHOWERS AND THUNDERSTORMS
ALONG AND AHEAD OF THE FRONTAL BOUNDARY IN THE NEBRASKA PANHANDLE
MONDAY AFTERNOON.
TUESDAY-THURSDAY:
SLIGHTLY COOLER AND DRIER CONDITIONS WILL BE ON TAP FOR AREAS
EAST OF THE LARAMIE RANGE ON TUESDAY AS WEAK SURFACE HIGH PRESSURE
BUILDS INTO THE PLAINS. THIS TREND IS EXPECTED TO CONTINUE THROUGH
WEDNESDAY. MEANWHILE...ANOTHER WEAK UPPER LEVEL DISTURBANCE IS
EXPECTED TO MOVE THROUGH MONTANA AND THE NORTHERN PLAINS ON
WEDNESDAY AND WEDNESDAY NIGHT. MOISTURE AGAIN WILL BE QUITE
LIMITED...SO WE ARE NOT EXPECTING MUCH IN THE WAY OF PRECIPITATION.
CONDITIONS MAY TURN SLIGHTLY COOLER ON THURSDAY...BUT TEMPERATURES
SHOULD STILL STAY ON THE WARM SIDE FOR THIS TIME OF YEAR.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 442 PM MDT FRI SEP 4 2015
USED LATEST HRRR GUIDANCE FOR THE 00Z TAFS. SHOWING A BAND OF
SHOWERS AND THUNDERSTORMS MOVING NORTHEAST OUT OF COLORADO THIS
EVENING...IMPACTING KCYS AND AIRPORTS EAST THROUGH 05Z.
SHOWERS/TSTMS ENDING FROM SOUTH TO NORTH AS THE EVENING
PROGRESSES.
&&
.FIRE WEATHER...
ISSUED AT 318 PM MDT FRI SEP 4 2015
MOIST SOUTHWEST FLOW ALOFT WILL BRING ANOTHER ROUND OF SCATTERED
SHOWERS AND WEAK THUNDERSTORMS TO THE AREA THIS AFTERNOON AND
EVENING WITH A NEAR REPEAT FOR SATURDAY. THE ONLY FIRE WEATHER
CONCERN THROUGH SATURDAY EVENING IS THE POSSIBILITY FOR A FEW
LIGHTNING STRIKES THAT COULD START A WILDFIRE BUT OVERALL THIS
IS A MINIMAL CONCERN.
THE MAIN FIRE WEATHER CONCERN IS SUNDAY FOLLOWING THE PASSAGE
OF A COLD FRONT. WESTERLY WINDS WILL DEVELOP SUNDAY WITH FREQUENT
WIND GUSTS OF 30 TO 40 MPH ACROSS THE FORECAST AREA. RELATIVE
HUMIDITY VALUES ARE EXPECTED TO DIP INTO THE TEENS AND 20S.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...FIRE WEATHER WATCH FROM SUNDAY MORNING THROUGH SUNDAY EVENING
FOR WYZ301>303-308.
NE...NONE.
&&
$$
SHORT TERM...SML
LONG TERM...REC
AVIATION...GCC
FIRE WEATHER...SML
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1050 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 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1043 PM MDT SAT SEP 5 2015
ISOLD TO SCT SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH ABOUT
09Z IN TWO MAIN AREA. ONE AREA OF STORM WILL FOCUS ALONG A LINE
OVER NE UT AND NW CO EXTENDING FROM ABOUT KPUC TO NW OF KCAG. THE
SECOND AREA WILL BE OVER SW CO FROM KMTJ SOUTH. STORM WILL AFFECT
KVEL...KMTJ...KTEX AND KDRO WITH CIG/VIS DROPPING BRIEFLY BELOW
ILS BREAK POINTS. AFTER 18Z TODAY STORMS ISOLATED STORMS WILL
REDEVELOP MAINLY SOUTH OF THE I-70 CORRIDOR.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...TGR/JOE
LONG TERM...JOE
AVIATION...CC
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1141 PM MDT SAT SEP 5 2015
.UPDATE...
ISSUED AT 744 PM MDT SAT SEP 5 2015
JUST COMPLETED AN UPDATE. BASED ON CURRENT CONDITIONS AND LATEST
TRENDS MADE SOME ADJUSTMENTS TO THE PRECIPITATION CHANCES THROUGH
THE REST OF THE NIGHT. A COUPLE OF BOUNDARIES ARE CURRENTLY DRAPED
ACROSS THE AREA. ONE SURFACE TROUGH IS OVER THE NORTHWEST CORNER
AND FAR NORTHERN COUNTIES WITH AN OUTFLOW REINFORCED BOUNDARY
EXTENDING FROM FAR WESTERN KANSAS TOWARD THE SOUTHWEST. NORTHERN
PORTION OF THIS BOUNDARY INTERSECTS WITH THE NORTHERN BOUNDARY.
SOME MINOR DEVELOPMENT HAS BEEN NOTED ON THESE BOUNDARIES. LATEST
FEW RUNS OF THE HRRR AND RAP INDICATE CONTINUED ALONG THESE
BOUNDARIES TO THE EAST OF THEM INTO THE OVERNIGHT HOURS. SO
EXPANDED THE SLIGHT CHANCE POPS TO COVER THESE AREAS. ALSO USED
THE RAP TO ADJUST THE WIND FIELD SINCE IT WAS CATCHING THESE
BOUNDARIES VERY WELL. ALSO MADE MINOR ADJUSTMENTS TO THE OVERNIGHT
TEMPERATURE FORECAST.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 1259 PM MDT SAT SEP 5 2015
THE UPPER LOW ROTATING THROUGH IDAHO THIS AFTERNOON WILL CONTINUE
TO LIFT INTO SOUTHERN CANADA BY SUNDAY AFTERNOON WITH A WEAK SHORT
WAVE TROUGH AXIS MOVING THROUGH THE NORTHERN AND CENTRAL ROCKIES
TONIGHT. THIS WILL PULL THE SURFACE LEE TROUGH EXTENDING FROM
EASTERN NEW MEXICO TO THE NEBRASKA PANHANDLE EASTWARD ACROSS THE
FORECAST AREA OVERNIGHT. GUSTY SOUTH WINDS AHEAD OF THE SURFACE
TROUGH ARE EXPECTED TO TURN NORTHWEST BY MID DAY ON SUNDAY ON THE
BACK SIDE OF THE SURFACE TROUGH.
DIURNALLY DRIVEN ISOLATED THUNDERSTORMS ARE DEVELOPING OVER THE
MOUNTAINS THIS AFTERNOON. A THUNDERSTORM OR SHOWER OR TWO CANNOT
BE TOTALLY RULED OUT OVERNIGHT ACROSS THE FORECAST AREA AS STORMS
ARE CARRIED OFF THE ROCKIES AND ACROSS THE PLAINS IN THE SOUTHWEST
FLOW ALOFT. MODELS HINT AT THE SHOWERS BEING MOSTLY ASSOCIATED
WITH THE UPPER SHORT WAVE TROUGH AS IT MOVES ACROSS THE AREA...BUT
MODELS ARE IN POOR AGREEMENT IN COVERAGE AREAS AND PRECIPITATION
AMOUNTS. HAVE GONE DRY WITH CONTINUED WARM TEMPERATURES AS
CONFIDENCE IN ANY LOCATION RECEIVING ANY MEASURABLE PRECIPITATION
IS EXTREMELY LOW.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 245 PM MDT SAT SEP 5 2015
SUNDAY NIGHT-MONDAY NIGHT...EXPECTING SOME DRY AIR ALOFT TO COVER
THE AREA VERY EARLY SUNDAY EVENING BUT AS THE EVENING/OVERNIGHT
PROGRESSES MODELS CONTINUE TO SHOW AN INCREASE FROM THE WEST AND
SOUTHWEST. THIS INCREASE IN MOISTURE APPEARS TO GET TAPPED BY THE
RIGHT REAR QUAD OF UPPER JET TO AT LEAST WARRANT A SLIGHT CHANCE FOR
SHOWERS/ISOLATED THUNDERSTORMS...PRIMARILY AFTER MIDNIGHT FOR THE
WESTERN 2/3 OF THE AREA. FOR MONDAY BETTER MID LEVEL MOISTURE SLOWLY
MOVES EAST BRINGING A DECREASING CHANCE OF THUNDERSTORMS TO THE
AREA. MAY SEE A FEW ISOLATED STORMS OVER FAR EASTERN COLORADO MONDAY
EVENING OTHERWISE WILL BE WATCHING A WEATHER DISTURBANCE DROP
THROUGH THE NORTHEAST 1/3 OR SO OF THE AREA SHORTLY BEFORE
MIDNIGHT...CONTINUING SOUTHEAST THROUGH SUNRISE TUESDAY MORNING.
WILL HAVE SOME SLIGHT CHANCE POPS TO START THINGS OFF.
LOW TEMPERATURES SUNDAY NIGHT IN THE MID 50S WEST TO LOW 60S EAST.
HIGH TEMPERATURES IN THE MID 80S TO LOW 90S WITH LOWS AGAIN IN THE
MID 50S TO LOW/MID 60S. FOR MONDAY NIGHT LOW TEMPERATURES
TUESDAY...NAM/ECMWF BRING DRIER AIR INTO THE AREA FROM THE NORTH
BEHIND A COLD FRONTAL PASSAGE. THERE IS SOME INSTABILITY ASSOCIATED
WITH SOME MAINLY MID LEVEL MOISTURE ALONG/SOUTH OF THE INTERSTATE BY
18Z BUT CIN IS HIGH. AS THE DRIER AIR MOVES IN CIN ERODES FAVORING
THE FAR SOUTHERN PARTS OF THE AREA FOR PERHAPS AN ISOLATED STORM OR
TWO. FOR TUESDAY NIGHT DRY AIR REMAINS ACROSS THE NORTHEAST/EAST 1/2
OF THE AREA WITH A BIT IN THE 700-500 LAYER ACROSS THE
WEST/SOUTHWEST 1/2. NO INSTABILITY TO WORK WITH AS SFC HIGH
INFLUENCING THE AREA AND REALLY DONT SEE MUCH CHANCE IF ANY CHANCE
FOR PRECIPITATION. HIGH TEMPERATURES IN THE LOW TO MID 80S WITH
OVERNIGHT LOWS IN THE LOW 50S TO AROUND 60.
WEDNESDAY...NOT TERRIBLY CONFIDENT IN THE PRECIPITATION CHANCES
GIVEN MODEL DISCREPANCIES REGARDING AVAILABLE MOISTURE. LITTLE
CHANGE MADE TO WHAT WAS INHERITED PER EXTENDED PROCEDURE SO FOR NOW
HIGHS 80-85 WITH LOWS AGAIN MID 50S TO AROUND 60.
THURSDAY...LOW CONFIDENCE FORECAST ONCE AGAIN. MODELS SEEM TO HINT
THAT A WEATHER DISTURBANCE...COLD FRONT AND INCREASING MOISTURE FOR
PRECIPITATION MAY BE HEADED TOWARD THE AREA FROM THE NORTHWEST.
ECMWF IS THE WETTER AND MUCH COLDER COMPARED TO THE GFS. 850MB
TEMPERATURES FROM THE ECMWF SHOW 10-16C FROM NORTHEAST TO SOUTHWEST
WHICH WOULD ONLY SUPPORT 60S FOR MOST OF THE AREA. GFS SHOWING UPPER
TEENS TO MID 20S WHICH IS CLOSER TO THE CURRENT FORECAST OF MID 70S
TO LOW 80S FOR HIGHS. LOW TEMPERATURES IN THE UPPER 40S TO LOW 50S.
FRIDAY...MUCH BETTER AGREEMENT IN THE 850MB TEMPERATURE FORECAST
FROM THE GFS/ECWMF WITH LOW TEENS WEST...UPPER TEENS/NEAR 20C WEST
WHICH SUPPORT HIGHS IN THE UPPER 60S TO MID 70S.
SATURDAY...LOOKING FOR DRY WEATHER WITH AFTERNOON TEMPERATURES
WARMING INTO THE MID 70S TO AROUND 80.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1130 PM MDT SAT SEP 5 2015
VFR CONDITIONS ARE EXPECTED ACROSS THE AREA THROUGH THE PERIOD.
FOR KGLD...ISOLATED SHRA/TSRA HAVE DEVELOPED NEAR AND UPSTREAM OF
KGLD. SO FOR THE FIRST 3 HOURS HAVE PUT IN VCTS. AFTER THAT THE
WINDS WILL SHIFT TO THE WEST AND THEN NORTH AS A PREFRONTAL TROUGH
AND FRONT MOVE THROUGH. THE WINDS WILL BECOME GUSTY AFTER THE
FRONT MOVES THROUGH WITH SUSTAINED WINDS NEAR 15 KNOTS AND GUSTS
TO NEAR 22 KNOTS. BY MID AFTERNOON THE WINDS BECOME MORE NORTHEAST
WITH THE GUSTINESS ENDING.
FOR KMCK...NO PRECIPITATION EXPECTED NEAR THE SITE. SAME KIND OF
WIND TRANSITION. SOUTHERLY WINDS SHIFT TO WEST THEN NORTH. SUSTAINED
WINDS WILL BE NEAR 15 KNOTS WITH GUSTS TO NEAR 22 KNOTS. BY MID
AFTERNOON THE WINDS BECOME MORE NORTHEAST WITH THE GUSTINESS
ENDING.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...LOCKHART
LONG TERM...99
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1140 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 06Z TAFS through 06Z Sunday Night)
Issued at 1132 PM CDT SAT SEP 5 2015
VFR conditions are expected to prevail through the period. Patchy cirrus
will continue to move across the region overnight. Scattered cu and
gusty winds will once again develop tomorrow afternoon as diurnal
heating ramps up. By evening, a cold front north of the area will
bring an increase in 10-15 kft deck and will thicken through the
remainder of the period as the front continues to sag southward.
Precipitation looks to hold off until after 06Z at all terminals.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
DISCUSSION...Leighton
AVIATION...PMM
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1150 PM MDT SAT SEP 5 2015
.AVIATION...
06Z TAF CYCLE
A MODERATE SOUTHWEST FLOW ALOFT WILL REMAIN IN PLACE THROUGH
SUNDAY. PATCHY FOG POSSIBLE ALONG THE RIO GRANDE VALLEY BOTTOM SUNDAY
MORNING W/ TEMPERATURES CURRENTLY ONLY SEVERAL DEGREES ABOVE
DEWPOINT TEMPERATURES. AS DRIER AIR ALOFT STARTS TO MOVE INTO THE
NORTHERN THIRD OF NM SUNDAY...SCT AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS MOST LIKELY OVER THE SOUTHWEST AND SOUTH-
CENTRAL MTS EWD TO THE EAST-CENTRAL AND SOUTHEAST PLAINS WITH
ISOD ACTIVITY POSSIBLE ELSEWHERE.
33
&&
.PREV DISCUSSION...813 PM MDT SAT SEP 5 2015...
.UPDATE...
UPDATED 1ST PERIOD FORECAST TO DECREASE POPS/QPF BASED ON LATEST
RADAR AND SATELLITE TRENDS. OTHERWISE...FORECAST ON TRACK. NEW
SUITE OF PRODUCTS OUT SHORTLY.
11
&&
.PREV DISCUSSION...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 MOISTURE 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.
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
11
AREA FORECAST DISCUSSION
NWS RALEIGH NC
433 AM EDT SUN SEP 6 2015
.SYNOPSIS...AN UPPER LEVEL LOW WILL RETROGRADE FROM THE SOUTHEAST
COAST TO THE NORTHERN GULF OF MEXICO TONIGHT...THEN STALL NEAR THE
TEXAS GULF COAST THROUGH MID-WEEK.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 330 AM SUNDAY...
OVERVIEW: A BROAD H3 LOW...CENTERED IN VICINITY OF CHARLOTTE AT 06Z
THIS MORNING...WILL RETROGRADE SLOWLY SOUTHWEST TOWARD THE NORTHERN
GULF OF MEXICO TODAY/TONIGHT. SMALL AMPLITUDE WAVES ROTATING
CYCLONICALLY AROUND THE EASTERN PERIPHERY OF THE UPPER LOW WILL
TRACK NORTHWARD ALONG THE GA/SC COAST AND WESTWARD INTO THE
CAROLINAS. A SFC RIDGE EXTENDING SOUTHWESTWARD THROUGH THE MID-
ATLANTIC INTO THE WESTERN CAROLINAS WILL PERSIST THROUGH TONIGHT.
MEANWHILE...AN EASTERLY /ONSHORE/ 925-850 MB FLOW WILL ADVECT RICH
LOW-LEVEL MOISTURE INLAND INTO THE CAROLINAS THROUGHOUT THE
DAY...WITH PWAT VALUES INCREASING INTO THE 1.75-2.00" RANGE THIS
AFTERNOON.
PRECIP: CONVECTION HAS BLOSSOMED OFFSHORE THE CAROLINA COAST THE
PAST FEW HRS IN ASSOC/W DPVA ATTENDANT SMALL AMPLITUDE SHORTWAVE
ENERGY ROUNDING THE EASTERN PERIPHERY OF THE H3 LOW CENTERED NEAR
CHARLOTTE NC. A DRY/STABLE AIRMASS WAS NOTED IN CENTRAL NC AT 06Z
THIS MORNING...IN ASSOC/W NOCTURNAL COOLING AND A DRY 925-850 MB
AIRMASS THAT ADVECTED SOUTHWEST INTO CENTRAL NC YESTERDAY EVENING.
AIRMASS MODIFICATION /DESTABILIZATION/ IS ALREADY UNDERWAY IN
COASTAL NORTH CAROLINA WHERE EASTERLY LOW-LEVEL FLOW HAS ADVECTED A
HIGHER THETA-E AIRMASS (925 MB DEWPOINTS ~18C) ONSHORE. THIS AIRMASS
IS EXPECTED TO PROGRESS INTO THE COASTAL PLAIN BY ~12Z...HWY 1
CORRIDOR BY 18Z THIS AFTERNOON...AND WESTERN PIEDMONT BY MID/LATE
AFTERNOON. SHORTWAVE ENERGY ROUNDING THE EASTERN PERIPHERY OF THE
UPPER LOW AT 07Z MAY OUTPACE THE UNSTABLE AIRMASS ADVECTING WESTWARD
TOWARD CENTRAL NC...AND CONVECTION CURRENTLY ALONG THE COAST APPEARS
UNLIKELY TO PROPAGATE AND/OR DEVELOP INLAND PRIOR TO SUNRISE.
HOWEVER...ADDITIONAL SHORTWAVE ENERGY PROGRESSING INTO THE AREA
BETWEEN 15-21Z WILL ENCOUNTER RICHER LOW-LEVEL MOISTURE (IN ADDITION
TO FAV DIURNAL TIMING)...AND SCATTERED TO WIDESPREAD CONVECTION IS
LIKELY TO PROPAGATE AND/OR DEVELOP WESTWARD INTO CENTRAL NC DURING
THAT TIME. EXPECT CHANCES FOR CONVECTION TO WANE THIS EVENING IN
ASSOC/W NOCTURNAL STABILIZATION AND SUBSIDENCE IN THE WAKE OF
SHORTWAVE ENERGY TRACKING WEST/SW ALONG THE NORTHERN PERIPHERY OF
THE UPPER LOW RETROGRADING TO THE NORTHERN GULF COAST.
HAZARDS: DEEP LAYER SHEAR WILL REMAIN INSUFFICIENT FOR CONVECTIVE
ORGANIZATION ASIDE FROM THE BRIEF MULTICELLULAR VARIETY (PRIMARILY
ALONG OUTFLOW). INCREASED MOISTURE ASSOC/W PERSISTENT ONSHORE FLOW
SHOULD RESULT IN MARGINAL DCAPE...THOUGH THE LATEST RAP GUIDANCE
INDICATES A REGION OF MODERATE DCAPE (750-1000 J/KG) PROGRESSING
INLAND INTO EASTERN NC BY LATE MORNING AND THE COASTAL PLAIN THIS
AFTERNOON. IF THIS OCCURS AS THE RAP SUGGESTS...EVAP COOLING AND
PRECIP LOADING WITHIN HIGHLY REFLECTIVE/ELEVATED CORES ATTENDANT
DEEP CONVECTION WOULD BE MORE LIKELY TO SUPPORT A POTENTIAL FOR
ISOLD SVR DOWNBURSTS. -VINCENT
&&
.SHORT TERM /MONDAY AND MONDAY NIGHT/...
AS OF 330 AM SUNDAY...
PRECIP CHANCES WILL DECREASE ON MONDAY AS THE UPPER LOW PROGRESSES
TO THE NORTHERN GOMEX AND SHORTWAVE ENERGY ROUNDING THE
EASTERN/NORTHERN PERIPHERY OF THE LOW REMAINS SOUTH/SOUTHWEST OF
CENTRAL NC...THOUGH SOME POTENTIAL FOR DIURNAL CONVECTION MAY
PERSIST IN THE COASTAL PLAIN...IN CLOSER VICINITY TO MORE FAVORABLE
MOISTURE AND WEAK LOW-LEVEL CONVERGENCE ATTENDANT AN INVERTED TROUGH
NEAR THE CAROLINA COAST. -VINCENT
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
AS OF 245 AM SUNDAY...
IT APPEARS THAT THE CHANCES OF MUCH NEEDED RAINFALL SHOULD INCREASE
ACROSS THE REGION BEGINNING WEDNESDAY... LASTING THROUGH FRIDAY AND
POSSIBLY INTO THE WEEKEND.
MOST MODEL SOLUTIONS DEPICT AN UPPER LEVEL LONG WAVE TROUGH TO MOVE
FROM THE NORTHERN PLAINS TO THE GREAT LAKES AND OHIO VALLEY MID TO
LATE WEEK. WITH THE UPPER RIDGE PLANTED OVER THE SOUTHEASTERN UNITED
STATES EXPECTED TO GRADUALLY BE BUMPED EASTWARD INTO THE WESTERN
ATLANTIC... A DEEP S-SW FLOW WILL BRING PLENTY OF GULF OF MEXICO
MOISTURE NORTHWARD INTO THE MEAN FRONTAL BOUNDARY. ONE FRONT IS
FORECAST TO WASH OUT OR STALL NEAR THE CENTRAL APPALACHIANS
WEDNESDAY WITH THE MAIN FRONT FORECAST TO APPROACH THE REGION FROM
THE WEST FRIDAY OR SATURDAY. THIS WOULD MEAN AN INCREASING CHANCE OF
MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS BEGINNING
WEDNESDAY. SHOWERS AND THUNDERSTORMS SHOULD BECOME MORE NUMEROUS AND
OCCUR ANY TIME OF THE DAY/NIGHT BY THURSDAY INTO SATURDAY.
HIGHS SHOULD REMAIN SUMMER-LIKE 85-90 WED... THEN LOWER INTO THE
LOWER TO MID 80S BY FRI-SAT. LOWS SHOULD GENERALLY BE IN THE 65-70
RANGE OR EVEN WARMER BEFORE THE FRONT ARRIVES LATE WEEK.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 200 AM SUNDAY...
24-HR TAF PERIOD: MVFR/IFR CEILINGS ARE EXPECTED TO DEVELOP BETWEEN
06-12Z THIS MORNING AT EASTERN TERMINALS (RDU/FAY/RWI) IN ASSOC/W AN
INCREASINGLY MOIST ONSHORE FLOW. FURTHER WEST AT INT/GSO...SUB-VFR
CEILINGS ARE UNLIKELY TO DEVELOP...THOUGH MVFR FOG WILL BE POSSIBLE
PRIOR TO AND JUST AFTER SUNRISE (09-12Z). CEILINGS/VISBYS WILL
LIFT/SCATTER TO VFR SEVERAL HRS AFTER SUNRISE (12-16Z) IN ASSOC/W
DIURNAL HEATING. SHOWERS/STORMS DEVELOPING IN VICINITY OF CAPE FEAR-
CAPE LOOKOUT EARLY THIS MORNING (06Z) SHOULD GRADUALLY TRACK AND/OR
DEVELOP FURTHER INLAND TO THE WEST/WNW TODAY...AND COULD AFFECT THE
FAY TERMINAL BY NOON. SCATTERED SHOWERS/STORMS ARE LIKELY TO AFFECT
MOST OR ALL TERMINALS THIS AFTERNOON AS AN UPPER LEVEL LOW
RETROGRADES SOUTHWESTWARD FROM THE CAROLINAS TOWARD THE NORTHERN
GOMEX. OUTSIDE OF CONVECTION...VFR CONDITIONS WILL PREVAIL THIS
AFT/EVE AND EARLY TONIGHT. DENSE FOG OR IFR/LIFR STRATUS WILL BE
POSSIBLE BY THE END OF THE TAF PERIOD EARLY MONDAY MORNING...
PARTICULARLY AT THE RDU/FAY/RWI TERMINALS.
LOOKING AHEAD: AN UNSETTLED PATTERN WILL PERSIST THROUGH MID-LATE
WEEK WITH ABOVE NORMAL CHANCES FOR CONVECTION IN ADDITION TO MORNING
STRATUS OR FOG. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM...VINCENT
LONG TERM...BADGETT
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
340 AM CDT SUN SEP 6 2015
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 340 AM CDT SUN SEP 6 2015
FORECAST CHALLENGE FOR THE SHORT TERM WILL BE ONGOING
CONVECTION EXITING THE CWA TO THE EAST AND ENTERING THE CWA
TO THE WEST. THE WESTERN ACTIVITY IS ASSOCIATED WITH A SFC
TROF/FRONT ROUGHLY ALONG A NORTHGATE TO MINOT TO STEELE TO
ASHLEY LINE...WITH MAJORITY OF CONVECTION IN N CNTRL ND.
HRRR HAS A DECENT HANDLE ON WRN ACTIVITY BUT MAY BE A BIT TOO
FAR WEST...IN GENERAL CLIPPING THE FAR NORTHWESTERN PORTION OF
THE CWA. WILL FOLLOW HRRR GUIDANCE BUT BRING CATEGORICAL POPS
FURTHER EAST AND JUST WEST OF DEVILS LAKE. HRRR DOES LIFT THIS
ACTIVITY OUT OF CONUS AND INTO MB BY 13Z.
FOCUS FOR AFTERNOON WILL BE HOW MUCH LOW LEVEL CLOUD CAN SCOUR
OUT AND TIMING FRONT INTO NW AND W CNTRL MN...WHICH SHOULD ARRIVE
IN FAR EASTERN ZONES NEAR PEAK HEATING. THE NAM CONTINUES TO SHOW
MUCAPES OF AROUND 1500 TO 2200 J/KG (HRRR VALUES ARE SIGNIFICANTLY
LESS) WITH BULK SHEAR AROUND 40 KTS IN THE HIGHEST CAPE AND
SLIGHTLY HIGHER BEHIND THE SFC BOUNDARY. CURRENT SPC SLIGHT RISK
AREA IS ALONG FAR EASTERN COUNTIES ALONG AND AHEAD OF
FRONT...HOWEVER NAM TIMING WOULD DRAG THE SEVERE POTENTIAL BACK
FURTHER INTO OTTER TAIL COUNTY ALONG THE SOUTHERN END OF THE
BOUNDARY. WILL MAKE LITTLE CHANGE TO PREV POPS FOR AFTN HOURS.
FRONT SHOULD EXIT CWA BY EVENING AND DRY WEATHER EXPECT FROM MID
EVENING THROUGH THE OVERNIGHT PERIOD...WITH COOL AND DRY AIR IN
THE MID 40S MOVING INTO NW ZONES.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 340 AM CDT SUN SEP 6 2015
MON NIGHT...SW FLOW ALOFT TURNING MORE ZONAL BY TUE MORNING.
A WEAK VORT MAX AND SWT ASSOCIATED WITH UPPER LOW OVER NRN
MANITOBA BRINGING A CHANCE OF WEAK SHOWERS IN THE FAR
NORTHEAST...AND WILL KEEP LOW POPS PER GOOD AGREEMENT BETWEEN
ECMWF/GFS/NAM SOLUTIONS. MAJORITY OF AREA HOWEVER WILL BE DRY
WITH MUCH COOLER AIR ENTERING FAR NW...OVERNIGHT LOWS IN THE
MID 40S AROUND LANGDON.
TUE AND TUE NIGHT...ZONAL FLOW WITH MODELS SHOWING A SFC LOW
ENTERING NORTH DAKOTA TUE NIGHT...ALTHOUGH SIGNIFICANT DIFFERENCE
ON TRACK OF LOW WITH NAM SHOWING SFC LOW OVER SRN SASK AT 12Z WED
COMPARED TO ECMWF IN CNTRL ND AND MORE BULLISH WITH SHOWERS. WILL
BRING LOW POPS INTO DVL BASIN BUT CONFIDENCE IS LOW ATTM.
WEDNESDAY THROUGH SATURDAY...MODELS GENERALLY AGREE WITH THE
OVERALL PATTERN PLACING THE REGION ON THE SOUTHERN END OF A STRONG
UPPER LOW PROPAGATING THROUGH CANADA. MOSTLY A DRY PERIOD...ALTHOUGH
ANY SHORTWAVES ROTATING THROUGH COULD LEAD TO BRIEF SHOWER CHANCES
(BEST CHANCES WED AND FRI). TEMPERATURES A BIT BELOW NORMAL
TRANSITIONING BACK TOWARD NEAR NORMAL VALUES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1148 PM CDT SAT SEP 5 2015
MESSY FCST THROUGH SUNDAY WITH EXPECTED LOWERING INTO IFR VSBYS OR
CIGS IN THE RRV AND ERN ND. TRICKY ON LOCATION AND TIMING. THEN
TIMING OF SHOWERS AND T-STORMS WITH FRONT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...SPEICHER
LONG TERM...TG/SPEICHER
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS BISMARCK ND
209 AM CDT SUN SEP 6 2015
.UPDATE...
ISSUED AT 207 AM CDT SUN SEP 6 2015
WITH THE LINE OF STORMS OVER CENTRAL NORTH DAKOTA GENERATING
SEVERE WIND GUSTS...WE ADDED COUNTIES AHEAD OF THE STORMS TO THE
WATCH AND EXTENDED IN TIME FOR A COUPLE OF HOURS. UPDATED PRODUCTS
ARE OUT.
UPDATE
ISSUED AT 128 AM CDT SUN SEP 6 2015
SEVERE THREAT REMAINS WITH THE LINE OF STORMS PUSHING RAPIDLY
NORTH AND EAST ACROSS CENTRAL NORTH DAKOTA. REMOVED SOUTHWESTERN
NORTH DAKOTA FROM THE WATCH...AND SEE NO PURPOSE TO ADD ADDITIONAL
COUNTIES AHEAD OF THE LINE OF STORMS.
UPDATE ISSUED AT 946 PM CDT SAT SEP 5 2015
THUNDERSTORMS CONTINUE TO INCREASE IN COVERAGE AND INTENSITY OVER
SOUTHEAST MONTANA DURING THE PAST HOUR. STRONG FORCING ASSOCIATED
WITH A SHORTWAVE LIFTING THROUGH CENTRAL MONTANA WITH A STILL
UNSTABLE AIRMASS OVER FAR SOUTHEAST MONTANA INTO SOUTHWEST NORTH
DAKOTA. BOTH HAIL AND WIND REPORTS FROM CONVECTION OVER SOUTHEAST
MONTANA. THINK THE MAIN THREAT FOR STRONG TO SEVERE THUNDERSTORMS
WILL BE OVER SOUTHWEST NORTH DAKOTA MAINLY ALONG AND SOUTH OF THE
INTERSTATE. ATMOSPHERE BECOMES MORE STABLE AS YOU MOVE NORTH OF
THE INTERSTATE. STILL EXPECT SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS EXTENDING INTO NORTHWEST AND EVENTUALLY THE NORTH
CENTRAL LATE TONIGHT. ALSO UNCERTAIN ABOUT INSTABILITY AS YOU
MOVE FROM THE SOUTHWEST INTO THE SOUTH CENTRAL BUT WITH WATCH IN
EFFECT EAST TO THE MISSOURI...WILL KEEP THE MENTION OF SEVERE HERE
AS WELL. UPDATED POPS BASED ON LATEST RADAR ANALYSIS WITH HRRR AND
EXP-HRRR FOR INPUT THROUGH AROUND 08 UTC.
UPDATE ISSUED AT 734 PM CDT SAT SEP 5 2015
UPDATE TO CLEAN UP POPS OVER EASTERN NORTH DAKOTA THIS EVENING.
LOOKS LIKE SHOWER AND ISOLATED THUNDERSTORM ACTIVITY SHOULD BE
MOVING OUT OF EASTERN PORTIONS OF CENTRAL NORTH DAKOTA IN A COUPLE
OF HOURS...THEN DRY SLOTTED UNTIL POSSIBLE SHOWERS MOVE INTO THE
AREA TOWARD MORNING.
UPDATE ISSUED AT 703 PM CDT SAT SEP 5 2015
SPC HAS ISSUED A SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
SOUTHWEST AND SOUTH CENTRAL NORTH DAKOTA...MAINLY SOUTH AND WEST
OF LAKE SAKAKAWEA AND THE MISSOURI RIVER. VERY MOIST AND UNSTABLE
ATMOSPHERE REMAINS ACROSS SOUTHWEST NORTH DAKOTA. TO THE WEST
CONVECTION HAS FIRED OFF THE BIGHORNS ALONG A BOUNDARY THAT
EXTENDS INTO FAR NORTHWEST SOUTH DAKOTA. ALSO...STRONG COLD FRONT
WILL BE PUSHING SOUTHEAST THROUGH EASTERN MONTANA THIS EVENING.
LATEST MESOSCALE MODELS HAVE NOT BEEN AS ROBUST AS EARLIER THIS
AFTERNOON...BUT IF WE DO GET CONVECTION FIRING OVER SOUTHEAST
MONTANA OR NORTHWEST SOUTH DAKOTA...IT WOULD LIKELY TRACK INTO
SOUTHWEST NORTH DAKOTA...WHERE MUCAPES REMAIN ABOVE 2000J/KG AND
0-6KM BULK SHEAR AROUND 50 KNOTS ADVECTS INTO THE AREA.
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 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 946 PM CDT SAT SEP 5 2015
IFR STRATUS AND PATCHY FOG HAS DISSIPATED MOST AREAS BUT IS
EXPECTED TO RETURN LATER TONIGHT INTO SUNDAY MORNING. SCATTERED
TO NUMEROUS SHOWERS AND THUNDERSTORMS HAVE MOVED INTO THE EASTERN
DAKOTAS...WITH ANOTHER ROUND ENTERING WESTERN NORTH DAKOTA LATER
TONIGHT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
128 AM CDT SUN SEP 6 2015
.UPDATE...
ISSUED AT 128 AM CDT SUN SEP 6 2015
SEVERE THREAT REMAINS WITH THE LINE OF STORMS PUSHING RAPIDLY
NORTH AND EAST ACROSS CENTRAL NORTH DAKOTA. REMOVED SOUTHWESTERN
NORTH DAKOTA FROM THE WATCH...AND SEE NO PURPOSE TO ADD ADDITIONAL
COUNTIES AHEAD OF THE LINE OF STORMS.
UPDATE ISSUED AT 946 PM CDT SAT SEP 5 2015
THUNDERSTORMS CONTINUE TO INCREASE IN COVERAGE AND INTENSITY OVER
SOUTHEAST MONTANA DURING THE PAST HOUR. STRONG FORCING ASSOCIATED
WITH A SHORTWAVE LIFTING THROUGH CENTRAL MONTANA WITH A STILL
UNSTABLE AIRMASS OVER FAR SOUTHEAST MONTANA INTO SOUTHWEST NORTH
DAKOTA. BOTH HAIL AND WIND REPORTS FROM CONVECTION OVER SOUTHEAST
MONTANA. THINK THE MAIN THREAT FOR STRONG TO SEVERE THUNDERSTORMS
WILL BE OVER SOUTHWEST NORTH DAKOTA MAINLY ALONG AND SOUTH OF THE
INTERSTATE. ATMOSPHERE BECOMES MORE STABLE AS YOU MOVE NORTH OF
THE INTERSTATE. STILL EXPECT SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS EXTENDING INTO NORTHWEST AND EVENTUALLY THE NORTH
CENTRAL LATE TONIGHT. ALSO UNCERTAIN ABOUT INSTABILITY AS YOU
MOVE FROM THE SOUTHWEST INTO THE SOUTH CENTRAL BUT WITH WATCH IN
EFFECT EAST TO THE MISSOURI...WILL KEEP THE MENTION OF SEVERE HERE
AS WELL. UPDATED POPS BASED ON LATEST RADAR ANALYSIS WITH HRRR AND
EXP-HRRR FOR INPUT THROUGH AROUND 08 UTC.
UPDATE ISSUED AT 734 PM CDT SAT SEP 5 2015
UPDATE TO CLEAN UP POPS OVER EASTERN NORTH DAKOTA THIS EVENING.
LOOKS LIKE SHOWER AND ISOLATED THUNDERSTORM ACTIVITY SHOULD BE
MOVING OUT OF EASTERN PORTIONS OF CENTRAL NORTH DAKOTA IN A COUPLE
OF HOURS...THEN DRY SLOTTED UNTIL POSSIBLE SHOWERS MOVE INTO THE
AREA TOWARD MORNING.
UPDATE ISSUED AT 703 PM CDT SAT SEP 5 2015
SPC HAS ISSUED A SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
SOUTHWEST AND SOUTH CENTRAL NORTH DAKOTA...MAINLY SOUTH AND WEST
OF LAKE SAKAKAWEA AND THE MISSOURI RIVER. VERY MOIST AND UNSTABLE
ATMOSPHERE REMAINS ACROSS SOUTHWEST NORTH DAKOTA. TO THE WEST
CONVECTION HAS FIRED OFF THE BIGHORNS ALONG A BOUNDARY THAT
EXTENDS INTO FAR NORTHWEST SOUTH DAKOTA. ALSO...STRONG COLD FRONT
WILL BE PUSHING SOUTHEAST THROUGH EASTERN MONTANA THIS EVENING.
LATEST MESOSCALE MODELS HAVE NOT BEEN AS ROBUST AS EARLIER THIS
AFTERNOON...BUT IF WE DO GET CONVECTION FIRING OVER SOUTHEAST
MONTANA OR NORTHWEST SOUTH DAKOTA...IT WOULD LIKELY TRACK INTO
SOUTHWEST NORTH DAKOTA...WHERE MUCAPES REMAIN ABOVE 2000J/KG AND
0-6KM BULK SHEAR AROUND 50 KNOTS ADVECTS INTO THE AREA.
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 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 946 PM CDT SAT SEP 5 2015
IFR STRATUS AND PATCHY FOG HAS DISSIPATED MOST AREAS BUT IS
EXPECTED TO RETURN LATER TONIGHT INTO SUNDAY MORNING. SCATTERED
TO NUMEROUS SHOWERS AND THUNDERSTORMS HAVE MOVED INTO THE EASTERN
DAKOTAS...WITH ANOTHER ROUND ENTERING WESTERN NORTH DAKOTA LATER
TONIGHT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
248 AM CDT SUN SEP 6 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 248 AM CDT SUN SEP 6 2015
SHORT TERM CONCERNS DOMINATED BY RAIN CHANCES AS THE COLD FRONT
APPROACHES AND THEN MOVES THROUGH. WARM ADVECTION AND WEAK SHORT
WAVE RIPPLES IN THE UPPER FLOW HELPING FUEL CONVECTION ACROSS
MN...WHICH WAS MOVING NORTHEASTWARD. THIS IS WELL AHEAD OF THE
COLD FRONT. LOW LEVEL JET HELPING MAINTAIN THIS CONVECTION AND
EVEN ENHANCING DEVELOPMENT ON THE SOUTHERN FLANK PER RADAR LOOPS.
THIS LINE OF CONVECTION WAS TRANSLATING SLOWLY EASTWARD...BUT THE
FEELING IS THAT DAYLIGHT WILL ARRIVE...THE LOW LEVEL JET WILL
WEAKEN...AND THIS CONVECTION WILL DISSIPATE FOR THE MOST PART. BUT
PARTS OF IT MAY SURVIVE TO IMPACT THE FAR WESTERN AND NORTHERN
PORTIONS OF THE FORECAST AREA. PARTIAL SUNSHINE TODAY SHOULD
ALLOW FOR FOR ANOTHER WARM AND HUMID DAY...WITH INCREASING
INSTABILITY AHEAD OF THE APPROACHING FRONT. THIS SETS THE STAGE
FOR RENEWED CONVECTIVE DEVELOPMENT BY AFTERNOON AS ANOTHER SHORT
WAVE AND JET STREAK ACT ON THE AVAILABLE INSTABILITY. BEST SHEAR
LAGS THE FRONT...BUT THERE IS ENOUGH SPEED IN THE UNIDIRECTIONAL
FLOW TO HELP MAINTAIN STRONG CONVECTION. THERE IS A SMALL CHANCE
FOR HAIL WITH STRONGER STORMS...AND THERE COULD BE SOME WIND
CONCERNS IF STORMS ORIENT NORMAL TO THE FLOW. PERHAPS EVEN A
GREATER CONCERN IS LOCALLY HEAVY RAINFALL. AXIS OF HIGHEST PW OF
NEARLY 2 INCHES ORIENTED ALONG THE FRONTAL BOUNDARY. SO IF STORMS
TRAIN AT ALL OVER ANY LOCATION...COULD PERHAPS SEE SOME LOCALIZED
WATER ISSUES.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 248 AM CDT SUN SEP 6 2015
FRONT MAKES ITS WAY EAST OF THE FORECAST AREA ON MONDAY. RAIN
LOOKS TO LINGER OVER THE SOUTHEAST THIRD EARLY IN THE DAY. BUT
THEN THE FRONT LOOKS TO HANG UP OVER IA...AND A NEW ROUND OF
CONVECTION IS EXPECTED TO DEVELOP THERE AND MAY THEN SPREAD
NORTHEAST TOWARD SOUTHERN WI AGAIN FOR THE AFTERNOON AND EVENING.
MODELS THEN SHOW ANOTHER SIGNIFICANT SHORT WAVE BLASTING EAST
ACROSS THE PLAINS AND INTO THE CENTRAL PART OF THE COUNTRY BY
TUESDAY MORNING. THIS SHOULD AGAIN AID IN CONVECTIVE ACTIVITY
ALONG THE BOUNDARY LINGERING JUST TO THE SOUTH OF OUR AREA. THUS
HAVE TO MAINTAIN RAIN CHANCES FOR THIS ALL THE WAY THROUGH
TUESDAY. HIGH PRESSURE SHOULD HELP MAINTAIN DRY CONDITIONS FOR
WEDNESDAY...BUT A LONG WAVE TROUGH DEVELOPS OVER THE HUDSON BAY
AREA AND SENDS MORE SHORT WAVE ENERGY DOWN INTO THE AREA FOR THE
END OF THE WEEK. SOME VERY FALL-LIKE CONDITIONS WILL BE FELT BY
FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1142 PM CDT SAT SEP 5 2015
THE THREAT FOR ANY SHOWERS OVERNIGHT LOOKS TO BE PRETTY SLIM AT
THIS POINT. THE RAP RUNS THROUGH THE EVENING HAVE BEEN PUSHING THE
WEAK ARM OF MOISTURE TRANSPORT FARTHER AND FARTHER NORTHEAST
WHILE THE RUNS OF THE HRRR AND CR-HRRR HAVE NOT SUGGESTED ANYTHING
WILL DEVELOP ON THIS TRANSPORT. STILL WILL BE CLOSE ON WIND SHEAR
OVERNIGHT BUT THE 06.00Z NAM CONTINUES TO SUGGEST THE WINDS WILL
BE JUST STRONG ENOUGH AT THE SURFACE TO STAY UNDER THE WIND SHEAR
CRITERIA AS THE WINDS AT 1500 TO 2000 FEET INCREASE TO 35 TO 40
KNOTS. STILL SOME DIFFERENCES BETWEEN THE MESO-MODELS ON THE
TIMING FOR THE CONVECTION WITH THE COLD FRONT SUNDAY AFTERNOON AND
EVENING. THE 06.00Z CR-NAM NEST HAS COME IN VERY CLOSE TO WHAT THE
05.12Z HI-RES NMM WAS SHOWING WHICH WOULD SUGGEST KRST COULD BE
IMPACTED LATE SUNDAY AFTERNOON INTO THE EARLY EVENING AND KLSE
GETTING HIT EARLY IN THE EVENING. HAVE NOT GONE TO PREVAILING TSRA
AT THIS POINT AS THESE MODELS ALSO CONTINUE TO SUGGEST A SPLIT
WILL OCCUR IN THE LINE WITH A POTENTIAL FOR THE ACTIVITY TO GO
NORTH AND SOUTH OF THE THE AREA...ESPECIALLY KLSE. THE 06.00Z NAM
FORECAST SOUNDINGS SUGGEST THE ACTIVITY MAY COME THROUGH WITH VFR
CEILINGS BUT WENT A BIT MORE PESSIMISTIC WITH MVFR VISIBILITY AND
CEILINGS FOR BOTH SITES. THERE COULD BE SOME EMBEDDED IFR
VISIBILITIES IN THE HEAVIER CELLS BUT CONFIDENCE NOT HIGH ENOUGH
TO INCLUDE AT THIS TIME BUT WOULD TEND TO THINK KRST WOULD STAND A
BETTER CHANCE OF SEEING THIS THAN KLSE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...MW
LONG TERM...MW
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1142 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 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1142 PM CDT SAT SEP 5 2015
THE THREAT FOR ANY SHOWERS OVERNIGHT LOOKS TO BE PRETTY SLIM AT
THIS POINT. THE RAP RUNS THROUGH THE EVENING HAVE BEEN PUSHING THE
WEAK ARM OF MOISTURE TRANSPORT FARTHER AND FARTHER NORTHEAST
WHILE THE RUNS OF THE HRRR AND CR-HRRR HAVE NOT SUGGESTED ANYTHING
WILL DEVELOP ON THIS TRANSPORT. STILL WILL BE CLOSE ON WIND SHEAR
OVERNIGHT BUT THE 06.00Z NAM CONTINUES TO SUGGEST THE WINDS WILL
BE JUST STRONG ENOUGH AT THE SURFACE TO STAY UNDER THE WIND SHEAR
CRITERIA AS THE WINDS AT 1500 TO 2000 FEET INCREASE TO 35 TO 40
KNOTS. STILL SOME DIFFERENCES BETWEEN THE MESO-MODELS ON THE
TIMING FOR THE CONVECTION WITH THE COLD FRONT SUNDAY AFTERNOON AND
EVENING. THE 06.00Z CR-NAM NEST HAS COME IN VERY CLOSE TO WHAT THE
05.12Z HI-RES NMM WAS SHOWING WHICH WOULD SUGGEST KRST COULD BE
IMPACTED LATE SUNDAY AFTERNOON INTO THE EARLY EVENING AND KLSE
GETTING HIT EARLY IN THE EVENING. HAVE NOT GONE TO PREVAILING TSRA
AT THIS POINT AS THESE MODELS ALSO CONTINUE TO SUGGEST A SPLIT
WILL OCCUR IN THE LINE WITH A POTENTIAL FOR THE ACTIVITY TO GO
NORTH AND SOUTH OF THE THE AREA...ESPECIALLY KLSE. THE 06.00Z NAM
FORECAST SOUNDINGS SUGGEST THE ACTIVITY MAY COME THROUGH WITH VFR
CEILINGS BUT WENT A BIT MORE PESSIMISTIC WITH MVFR VISIBILITY AND
CEILINGS FOR BOTH SITES. THERE COULD BE SOME EMBEDDED IFR
VISIBILITIES IN THE HEAVIER CELLS BUT CONFIDENCE NOT HIGH ENOUGH
TO INCLUDE AT THIS TIME BUT WOULD TEND TO THINK KRST WOULD STAND A
BETTER CHANCE OF SEEING THIS THAN KLSE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...04
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
1039 AM EDT SUN SEP 6 2015
.SYNOPSIS...
A WEAK COASTAL TROUGH WILL MOVE INLAND EARLY THIS WEEK BEFORE
DISSIPATING. ATLANTIC HIGH PRESSURE WILL THEN REBUILD DURING MID
WEEK BEFORE A COLD FRONT APPROACHES THE AREA NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
LATE THIS MORNING...SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS CONTINUE TO MOVE SOUTHWESTWARD ACROSS THE COASTAL
WATERS WITHIN A BROAD CONVERGENCE ZONE OFFSHORE. A FEW OF THESE
SHOWERS HAVE TRIED TO BRUSH THE COAST AND PUSH INLAND...BUT HAVE
MAINLY STAYED OVER THE WATERS. ALOFT...TODAY WILL FEATURE A BROAD
AND WEAK UPPER LOW CENTERED OVER THE FORECAST AREA THAT WILL
SLOWLY RETROGRADE. AT THE SURFACE...THE BROAD CONVERGENCE ZONE
OVER THE WATERS WITHIN A WEAK COASTAL TROUGH WILL GRADUALLY PUSH
TOWARD THE COAST AND INLAND AREAS AS THE UPPER LOW STEPS WESTWARD.
THIS WILL HELP TO BRING AN INCREASE IN DEEP MOISTURE AND PWATS
WILL RISE TO AROUND 2 INCHES...ESPECIALLY ALONG THE COAST. THE
PWAT OFF THE 12Z KCHS SOUNDING WAS ONLY 1.7 INCHES...BUT THERE IS
A SHARP GRADIENT FROM EAST TO WEST INTO SOUTHEAST GEORGIA. MODEL
SOLUTIONS...ESPECIALLY THE HRRR AND THE RAP...SEEM TO BE FAVORING
THE TRI-COUNTY FOR THE MOST PRECIPITATION TODAY AND KEEPS INLAND
AREAS AND SOUTHEAST GEORGIA MOSTLY DRY. IT IS REASONABLE THAT THE
HIGHEST POPS NEED TO BE ALONG THE SOUTH CAROLINA COAST AND INCLUDE
THE TRI-COUNTY...BUT THE THINKING CONTINUES TO BE THAT SHOWERS AND
STORMS WILL DEVELOP JUST ABOUT EVERYWHERE ONCE MORNING STRATUS
MIXES OUT. MODIFYING THE 12Z SOUNDING GIVES CAPE VALUES IN EXCESS
OF 2500 J/KG SO THERE SHOULD BE PLENTY OF INSTABILITY FOR
THUNDERSTORM DEVELOPMENT. THE OVERALL SEVERE THREAT IS LOW SINCE
DCAPE VALUES ARE LOW...BUT GIVEN SUFFICIENT BOUNDARY INTERACTIONS
THERE COULD STILL BE A COUPLE OF STRONGER STORMS WITH THE
POTENTIAL FOR A WET MICROBURST. THE MAIN THINGS TO WATCH OUT FOR
THOUGH WILL BE LOCALLY HEAVY RAINFALL AND LIGHTNING. TEMPERATURES
WILL BE COOLER WITH PLENTY OF CLOUDS AROUND...LOOK FOR HIGHS IN
THE 85-87 DEGREE RANGE IN MOST AREAS.
TONIGHT THE INLAND CONVECTION SHOULD DIE DOWN ONCE WE LOSE DAYTIME
HEATING...THEN ANOTHER ROUND OF CONVECTION WILL FIRE OVER THE
COASTAL WATERS IN RESPONSE TO CONVERGENCE IN THE COASTAL TROUGH.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
MONDAY...SLIGHTLY COOLER CONDITIONS WILL PERSIST AS A NORTHEAST FLOW
OCCURS BETWEEN HIGH PRESSURE INLAND AND A COASTAL TROUGH ALONG THE
SOUTHEASTERN UNITED STATES. ALOFT...A MID/UPPER LVL LOW WILL SLOWLY
RETROGRADE SOUTHWEST TOWARD THE GULF OF MEXICO...LEADING TO A
FAVORABLE SETUP FOR DEEP MOISTURE TO RETURN TO THE AREA. GUIDANCE
INDICATES PWATS AROUND 2.0 INCHES BY THE AFTERNOON...HELPING SUPPORT
AT LEAST SCATTERED SHOWERS AND THUNDERSTORMS OVER MUCH OF THE AREA.
HIGH TEMPS WILL RANGE IN THE MID TO UPPER 80S AWAY FROM THE COAST.
OVERNIGHT LOWS WILL BE AROUND 70 AWAY FROM THE COAST.
TUESDAY AND WEDNESDAY...THE MID/UPPER LVL LOW WILL CONTINUE TO
RETROGRADE OVER THE GULF OF MEXICO AND WEAKEN WHILE SFC HIGH PRESSURE
DEVELOPS AND BECOMES MORE ESTABLISHED OVER THE WESTERN ATLANTIC BY
MID WEEK. FURTHER INLAND...WEAK TROUGHING WILL DEVELOP...
SUGGESTING A MORE TYPICAL SUMMERTIME PATTERN. DEEP LAYERED
MOISTURE WILL REMAIN OVER THE AREA WITH PWATS AROUND 2.0 INCHES.
SCATTERED SHOWERS AND THUNDERSTORMS WILL REMAIN IN THE FORECAST
EACH DAY...WITH ISOLATED STRONG THUNDERSTORMS POSSIBLE AT TIMES.
OVERALL HIGH TEMPS SHOULD RANGE IN THE UPPER 80S TO AROUND
90...WARMEST ON WEDNESDAY. OVERNIGHT LOWS WILL RANGE IN THE LOWER
70S AWAY FROM THE COAST.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
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 /15Z SUNDAY THROUGH THURSDAY/...
MORNING IFR STRATUS IS STEADILY MIXING OUT AND LIFTING TO BECOME A
MVFR STRATOCUMULUS DECK. MVFR CONDITIONS WILL LIKELY LINGER FOR A
COUPLE OF HOURS...TILL AROUND NOON. FAIRLY GOOD COVERAGE OF
SHOWERS AND TSTMS EXPECTED TODAY MAINLY ALONG THE SEA BREEZE. WE
MAINTAINED VICINITY SHOWERS AT KCHS FOR THE AFTERNOON WITH
SLIGHTLY LATER ONSET AT KSAV. ANY CONVECTION SHOULD DISSIPATE
AROUND SUNSET. GIVEN THE PERSISTENT COOL NNE FLOW WITH HIGH
PRESSURE TO THE NORTH...ANOTHER ROUND OF MVFR OR IFR STRATUS IS
POSSIBLE LATE TONIGHT.
EXTENDED AVIATION OUTLOOK...VFR CONDITIONS ARE EXPECTED TO PREVAIL
AT BOTH CHS AND SAV TERMINALS. HOWEVER...THERE COULD BE BRIEF FLIGHT
RESTRICTIONS DUE TO EARLY MORNING FOG OR SHOWERS AND THUNDERSTORMS
EACH AFTERNOON.
&&
.MARINE...
THROUGH TONIGHT...MAINLY NE FLOW TO PERSIST OVER THE WATERS. A
ROBUST COASTAL SEA BREEZE IS ANTICIPATED THIS AFTERNOON WITH SOME
GUSTS APPROACHING 20 KT. OTHERWISE...TONIGHT WINDS SHOULD WEAKEN
SOMEWHAT AS THE COASTAL TROUGH WEAKENS.
MONDAY THROUGH FRIDAY...NORTHEAST WINDS AT OR BELOW 10-15 KTS WILL
PERSIST ON MONDAY BETWEEN HIGH PRESSURE INLAND AND A COASTAL TROUGH
OFF THE SOUTHEAST COAST. SCATTERED TO NUMEROUS THUNDERSTORMS ARE
POSSIBLE INTO MONDAY NIGHT BEFORE THE COASTAL TROUGH SHIFTS ONSHORE
AND WEAKENS. THE FLOW SHOULD THEN WEAKEN AND VEER TO MORE EASTERLY
ON TUESDAY THEN SOUTH-SOUTHWEST ON WEDNESDAY AS HIGH PRESSURE
DEVELOPS OVER THE WESTERN ATLANTIC. 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.
&&
$$
NEAR TERM...BSH/JRL
SHORT TERM...DPB
LONG TERM...DPB
AVIATION...JRL/DPB
MARINE...JRL/DPB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1006 AM CDT SUN SEP 6 2015
.UPDATE...
ISSUED AT 1006 AM CDT SUN SEP 6 2015
THE HWO WAS UPDATED SHORTLY AFTER THE 12Z UPDATE POSTED TO THE SPC
DAY 1 SVR OUTLOOK. REMOVED MENTION OF TORNADO POTENTIAL. THIS
SETUP IS NOT FAVORABLE FOR TOR`S.
THE FRONT IS NOW VISIBLE ON OUR RADAR...ROUGHLY LOCATED FROM
GREELEY-LOUP CITY-OVERTON-ELWOOD. IT`S MOVEMENT IS ESE AT 26 KTS.
IF IT MAINTAINS THIS MVMT...IT WILL BE EXITING THE SE CORNER OF
OUR FCST AREA (HEBRON-BELOIT) BY 1830Z! THAT WOULD EFFECTIVELY END
WHATEVER LITTLE POTENTIAL FOR THUNDER EXISTS.
LOOKING AT THE LATEST RUC/HRRR AND THE 12Z NAM...THEY ALL HAVE THE
CURRENT LOCATION OF THE FRONT...BUT ARE MUCH SLOWER WITH ITS FWD
MVMT. THE 12Z NAM IS 15 KTS AND DOES NOT BRING THE FRONT TO THE SE
FRINGE OF THE FCST AREA UNTIL 00Z. THE 13Z HRRR ACTUALLY SLOWS THE
FRONT DOWN 17Z-19Z ACROSS THE HEART OF THE FCST AREA...THEN IT
RESUMES ITS SE PROGRESS. I JUST DON`T SEE THAT HAPPENING.
FOR WHAT IT`S WORTH...THE 12Z NAM ACTUALLY MAINTAINS CONTINUITY
WITH YESTERDAY`S MODELS...STALLING THE FRONT FROM HEBRON-OSBORNE
LATE THIS AFTERNOON INTO TONIGHT.
GIVEN THE DEEP SW FLOW ALOFT...IT IS QUITE PROBABLE THE FRONT
WILL SLOW ITS FWD PROGRESS...IT`S JUST A MATTER OF HOW SOON AND
WHERE. WILL CONT TO MONITOR...
FOR NOW...WE`LL BE UPDATING THE WIND FCST SHORTLY TO BETTER
REFLECT FRONTAL LOCATION/PASSAGE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 401 AM CDT SUN SEP 6 2015
ANOTHER UNSEASONABLY WARM SEPTEMBER DAY IS ANTICIPATED ACROSS THE
LOCAL AREA THIS AFTERNOON AS A COLD FRONT ACROSS NORTHERN NEBRASKA
WORKS ITS WAY SOUTHEASTWARD. EXPECT SOME ADIABATIC COMPRESSION
AHEAD OF THIS FRONT TO LEAD TO ANOTHER WARM AFTERNOON WITH HIGH
TEMPERATURES IN THE MID 90S FOR MOST AREAS...AND THESE WARM
READINGS ALONG WITH THE ANTICIPATED DECREASING WINDS ASSOCIATED
WITH THE SURFACE TROUGH...WILL MAKE FOR A VERY HOT...HUMID AND
LIKELY UNCOMFORTABLE AFTERNOON FOR THE MAJORITY OF THE FORECAST
AREA.
WHILE THERE WILL BE A SMALL CHANCE FOR SOME SHOWER AND
THUNDERSTORM DEVELOPMENT AHEAD OF THIS FRONT...MOST AREAS WILL
LIKELY REMAIN DRY AS THE FOCUS OF THIS ACTIVITY WILL LIE PRIMARILY
SOUTHEAST OF THE LOCAL AREA. THAT SAID...IF STORMS ARE ABLE TO
INITIATE THIS AFTERNOON...GOOD INSTABILITY SHOULD ALLOW THESE
STORMS TO RAPIDLY INTENSIFY...POSSIBLY PRODUCING STRONG
THUNDERSTORM WIND GUSTS AND SMALL HAIL. THANKS TO FAIRLY MARGINAL
SHEAR...THE TORNADO RISK WILL BE LOW...ALBEIT NOT COMPLETELY NON-
EXISTENT THANKS TO THE PRESENCE OF THE PASSING FRONTAL BOUNDARY.
NOT SURPRISINGLY... ROUGHLY THE EASTERN HALF OF THE FORECAST AREA
IS HIGHLIGHTED IN A MARGINAL RISK FOR SEVERE WEATHER FROM THE
STORM PREDICTION CENTER FOR TODAY...INCLUDING A 2 PERCENT RISK FOR
TORNADOES.
WHILE THERE MAY BE A BRIEF FEW HOURS OF INCREASED NORTHERLY WINDS
BEHIND THE FRONTAL BOUNDARY...ONCE THIS SURGE OF STRONGER WINDS
DIMINISHES...LIGHTER NORTHERLY WINDS AND MUCH COOLER TEMPERATURES
AREA EXPECTED IN THE WAKE OF THIS APPROACHING FRONT. WHILE NOT
UNSEASONABLY COOL...TEMPERATURES ARE FORECAST TO FALL INTO THE
UPPER 50S ACROSS OUR NORTHERN COUNTIES...AND INTO MIDDLE 60S
ACROSS NORTH CENTRAL KANSAS. NORMAL HIGH TEMPERATURES FOR THE TRI-
CITIES THIS TIME OF YEAR ARE IN THE MIDDLE 50S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 401 AM CDT SUN SEP 6 2015
BIGGEST ISSUE WILL BE GETTING A GOOD HANDLE ON HOW FAST COOLER
AND DRIER AIR MOVES IN.
AT THE SYNOPTIC LEVEL...A SHORTWAVE TROUGH WILL ENTER THE PLAINS
BY AFTERNOON/EVENING AND COULD HELP SPAWN SOME THUNDERSTORMS ALONG
AND NORTH OF A STALLED SURFACE BOUNDARY NEAR THE SOUTHERN FRINGE
OF THE CWA. SOMEWHAT MODEST UPPER LEVEL FLOW AT THE BASE OF THE
TROUGH WILL MOVE INTO OUR REGION...AND WITH INSOLATION...COULD
SPARK SOME STRONG STORMS AS INSTABILITY INCREASES...ESPECIALLY
SOUTH AND EAST.
YET ANOTHER WAVE IS FORECAST TO SWING THROUGH ON TUESDAY AND WITH
A BOUNDARY POTENTIALLY NEARBY IN THE SOUTH...WE COULD GET MORE
THUNDERSTORMS...BUT COOLER TEMPERATURES ARE EXPECTED WITH HIGHS
ONLY REACHING NEAR 80 FOR MUCH OF SOUTH CENTRAL NEBRASKA...AND
PERHAPS MID 80S IN NORTH CENTRAL KANSAS AS COOLER AND DRIER AIR
CONTINUES TO MOVE IN. WITH COOLER AND DRIER AIR COMES LESS
INSTABILITY...SO STRONG STORMS ARE NOT AS BIG OF A CONCERN.
SHOWERS AND THUNDERSTORMS ARE A POSSIBILITY THROUGH FRIDAY NIGHT
...AS A SERIES OF WAVES MOVE BY WITHIN NORTHWEST FLOW...WITH
MODELS TRENDING TOWARD LATER BUILDING OF THE WESTERN RIDGE TO THE
EAST AS COMPARED TO PREVIOUS FORECASTS. BY SATURDAY...WE SHOULD
BEGIN DRYING OUT AS THE UPPER RIDGE BECOMES MORE PROMINENT IN OUR
AREA AS A COOLING TREND CONTINUES THROUGH THE WORK WEEK AND INTO
THE WEEKEND. WENT WITH CONSRAW FOR HIGH TEMPERATURES FRIDAY AND
ADJMEN FOR LOWS TUESDAY MORNING AS A STARTING POINT...AS
SUPERBLEND APPEARS ABNORMALLY WARM FOR THIS PERIOD.
&&
.AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z MON MORNING)
ISSUED AT 628 AM CDT SUN SEP 6 2015
PLENTY OF MID LEVEL CLOUD COVER IS EXPECTED TO STREAM ACROSS THE
TERMINALS TODAY AHEAD OF A STRONG COLD FRONT EXPECTED TO REACH
KGRI AROUND 06/21Z. AHEAD OF THIS FRONT...EXPECT SOME LLWS TO BE
POSSIBLE FOR THE NEXT FEW HOURS BEFORE THE PRESSURE GRADIENT
RELAXES WITH THE PRECEDING SURFACE TROUGH. LATER THIS
AFTERNOON...EXPECT A SHIFT OF THE WINDS TO A MORE NORTHERLY
DIRECTION BEHIND THE PASSING COLD FRONT...WITH AN ISOLATED TSRA
ALSO POSSIBLE. KEPT A VCTS IN THE TAF FOR THE EVENING HOURS TO
COVER THIS WITH THE BEST CHANCES FOR ANY ACTIVITY NEAR THE
TERMINALS EXPECTED BEFORE MIDNIGHT TONIGHT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...ROSSI
LONG TERM...HEINLEIN
AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
331 AM 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.
&&
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT.
A LONE DECAYING SHOWER WAS MOVING NORTHEAST ACROSS THE PLATEAU
COUNTRY OF MOHAVE COUNTY EARLY THIS MORNING. HOWEVER, THIS INDICATES
THE ATMOSPHERE IS NOT SO DRY AND STABLE AND THUS SOME ADJUSTMENTS
WERE MADE TO THE FORECAST FOR TODAY. IF YOU ARE IN THE WESTERN AND
NORTHERN PARTS OF THE AREA TODAY, THIS WILL STILL BE A FANTASTIC DAY
FOR THIS TIME OF YEAR WITH DRY CONDITIONS COURTESY OF A SOUTHWEST
FLOW ALOFT AND BELOW NORMAL HIGH TEMPERATURES AND RELATIVELY LIGHT
WINDS MUCH OF THE DAY. SUNSHINE WILL BE PLENTIFUL IN THESE AREAS.
THE ALLEGED SWEEP OUT OF THE MOISTURE ACROSS THE SOUTHEASTERN PARTS
OF THE AREA THAT WAS SHOWN FOR DAYS HAS NEVER TAKEN PLACE. THERE IS
A MID/UPPER LEVEL TROUGH DIGGING SOUTH ACROSS NEVADA THIS MORNING
BUT THIS FEATURE WILL MAKE LITTLE HEADWAY SOUTH AND WILL JUST GET
HUNG UP ACROSS SOUTHERN NEVADA AND SLOWLY BECOME PARALLEL ENOUGH TO
THE FLOW ALOFT THAT IT WASHES OUT. THUS THE FEED OF TROPICAL
MOISTURE INTO ARIZONA WILL NOW HAVE A WINDOW TO OOZE A BIT FURTHER
WEST AND NORTH. THE QUESTION IS HOW FAR IN BOTH DIRECTIONS. THE
OPERATIONAL GFS HAS BEEN THE WETTEST MODEL AND IN ALL RESPECT NOT
DONE TOO BAD HANDLING THIS PATTERN. THUS IT WAS LEANED TOWARD WITH
THE FORECAST FOR THIS MORNING. THE OPERATIONAL ECMWF IS SORT OF IN
THE MIDDLE WITH THE WRF INITIALLY DRIER THEN WETTER.
IPW SENSORS SHOW PWATS BETWEEN A HALF AN INCH AND AN INCH ACROSS THE
SOUTHEAST THIRD OF THE AREA THIS MORNING. THESE VALUES ARE FORECAST
TO RISE THROUGH THE DAY TO BETWEEN 0.75 AND 1.30 INCH. THUS THIS
WILL OPEN THE DOOR FOR AREAS WITHIN ABOUT 25 MILES WEST OF THE
COLORADO RIVER VALLEY ON EAST TO SEE SHOWERS AND THUNDERSTORMS
AROUND THIS AFTERNOON AND EVENING. THE HRRR MODEL RAPIDLY SETS OFF
CONVECTION AROUND 11 AM OR SO TODAY IN THE PLATEAU COUNTRY OF MOHAVE
COUNTY, THEN DEVELOPS MORE ACTIVITY FURTHER SOUTH AND WEST. GIVEN
THIS, POPS WERE RAISED IN MOHAVE COUNTY BY NEARLY DOUBLE AND THE
MENTION OF SHOWERS AND THUNDERSTORMS WAS ADDED IN AS FAR NORTH AS
MESQUITE AND THE MOAPA RIVER VALLEY AND AS FAR WEST AS LAS VEGAS,
SEARCHLIGHT AND VIDAL JUNCTION. THE FLOW TODAY IS FROM THE SOUTH, SO
FOR THE LAS VEGAS VALLEY, ANY ACTIVITY THAT GETS GOING IN THE MOJAVE
NATIONAL PRESERVE OR THE MCCULLOUGH RANGE WILL HAVE THE POTENTIAL TO
WORK INTO THE VALLEY. THE BEST ODDS IN THE LAS VEGAS VALLEY WILL BE
IN THE SOUTHEAST PART OF THE VALLEY. THE WEST AND NORTH SIDES MAY
SEE NOTHING AT ALL. THE MODELS DO NOT BRING MUCH MOISTURE INTO THE
SPRING MOUNTAINS, SO WE WILL KEEP THEM DRY. IF YOU PLAN TO VENTURE
OUT TO THE LAKE TODAY, PLEASE KEEP AWARE OF THE CLOUDS AND HAVE A
WAY TO GET UPDATES ON THE WEATHER AS THE SITUATION MAY RAPIDLY
CHANGE. THE MAIN CONCERN TODAY WITH STORMS WILL BE FLASH FLOODING IN
ANY STRONGER OR TRAINING ACTIVITY AS WELL AS GUSTY WINDS. DCAPE
VALUES ON THE GFS ARE IMPRESSIVE SHOWING 1000-2000 J/KG TODAY WITH
THE HIGHEST VALUES OVER LAKE MEAD SOUTHWEST TOWARD SEARCHLIGHT. BY
CONTRAST THE ECMWF SHOWS VALUES OF 300 J/KG AT BEST.
ACTIVITY MAY NOT BE SO QUICK TO END TONIGHT AND IF THE GFS IS
CORRECT WE WILL SEE SHOWERS AND THUNDERSTORMS LAST OVERNIGHT. FOR
NOW, I NUDGED UP POPS A LITTLE MAINLY IN MOHAVE COUNTY. LOWS TONIGHT
WILL BE AT OR ABOVE WHAT WE SEE THIS MORNING.
TEMPS WILL BEGIN TO RISE ON MONDAY AND WARM FURTHER ON TUESDAY. THE
MAIN CHALLENGE WILL BE HOW MUCH MOISTURE IS AROUND IN THE MOJAVE
DESERT AND THUS CLOUD COVER. WE STILL HAVE LAS VEGAS RETURNING BACK
INTO THE TRIPLE DIGITS AT MCCARRAN ON TUESDAY AS THE WARMER ECMWF
AND GFS NUMBERS HAVE BEEN DOING BETTER LATELY.
THE FLOW ALOFT REMAINS SOUTHWEST TO WEST WHICH WILL KEEP WESTERN AND
NORTHERN AREAS DRY, HOWEVER, WE MAINTAINED SHOWERS AND THUNDERSTORMS
IN NEARLY SIMILAR AREAS TO WHAT WE HAVE IN TODAY FOR LABOR DAY. THE
BEST CHANCES WILL REMAIN IN MOHAVE COUNTY. AWAY FROM HEATING AND
TERRAIN AND ANY OLD OUTFLOW BOUNDARIES AROUND THE ONLY LARGE SCALE
FEATURE TO DRIVE CONVECTION WILL BE A 60 KT+ JET STREAM AT 250 MB
MOVING OVERHEAD ASSISTING IN LIFT ON MONDAY. THIS FEATURE MOVES AWAY
BY TUESDAY. THE WRF STARTS TO SHOW BETTER INSTABILITY AND MOISTURE
FURTHER WEST ON TUESDAY WITH ACTIVITY POSSIBLE AS FAR WEST AS THE
MORONGO BASIN. FOR NOW, I KEPT THINGS DRY OUT THAT WAY AS WELL AS
WEST OF THE COLORADO RIVER AS BOTH THE GFS AND ECMWF ARE DRIER AND
MORE STABLE. HOWEVER, WE WILL HAVE TO SEE HOW THINGS PLAY OUT AND
MAY NEED TO ADJUST THE FORECAST.
.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.
&&
.AVIATION...FOR MCCARRAN...WINDS WILL REMAIN SOUTHERLY THROUGH THIS
EVENING. BETWEEN 14Z AND 19Z WINDS WILL FAVOR A DIRECTION BETWEEN
130 AND 170 DEGREES WHICH COULD CAUSE CONFIGURATION ISSUES, HOWEVER,
SPEEDS ARE EXPECTED TO BE 4-8 KTS. WINDS WILL INCREASE AROUND 22Z
TODAY TO 8-12 KTS WITH GUSTS TO 18 KTS THEN DECREASE BETWEEN 02Z AND
04Z THIS EVENING. FEW-SCT CLOUDS AOA 10K-15K FEET. THERE IS THE
POSSIBILITY SHRA/TSRA MAY GET CLOSE ENOUGH TO THE SOUTH END OF THE
VALLEY THAT OUTFLOW BOUNDARIES COULD DEVELOP AND IMPACT WIND SPEED
AND DIRECTIONS. THERE IS A VERY SMALL CHANCE THAT A SHRA/TSRA COULD
EVEN DIRECTLY IMPACT THE TERMINAL BUT CONFIDENCE IS TOO LOW TO
INCLUDE IN THE TAF AT THIS TIME. ISOLATED SHRA/TSRA WILL BE AROUND
AFTER 18Z TODAY IN THE PEACH SPRINGS AND TO A LESSER EXTENT THE
MORMON MESA CORRIDORS.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...WINDS WILL MAINLY BE SOUTH TO SOUTHWEST AT 6-12 KTS
WITH GUSTS OF 12-20 KTS THIS AFTERNOON AND EARLY EVENING. BETWEEN
02Z AND 04Z MONDAY WINDS SHOULD DECREASE AND TREND TOWARD TYPICAL
DIURNAL DIRECTIONAL TRENDS FOR THE REST OF THE NIGHT. THE EXCEPTION
WILL BE NEAR ANY SHRA/TSRA WHERE GUSTY AND ERRATIC WINDS ARE
POSSIBLE. SHRA/TSRA ARE POSSIBLE TODAY AFTER 18Z AND MAINLY ENDING
BY 06Z MONDAY 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.
&&
.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 NEWPORT/MOREHEAD CITY NC
950 AM EDT SUN SEP 6 2015
.SYNOPSIS...
BROAD HIGH PRESSURE WILL BUILD INTO THE REGION THROUGH MID WEEK. A
WEAK TROUGH LOW PRESSURE AREA WILL LINGER NEAR THE SOUTHEAST COAST
THROUGH EARLY NEXT WEEK. A COLD FRONT WILL APPROACH THE AREA LATE
NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 945 AM SUNDAY...SHOWERS WITH SOME EMBEDDED THUNDERSTORMS
CONTINUE TO STREAM FROM EAST TO WEST ACROSS OUR SOUTHERN COASTAL
COUNTIES AND OVER THE CENTRAL OUTER BANKS. MADE SOME MINOR TWEAKS
TO THE POP GRIDS. PER THE LATEST 3KM HRRR AND RUC...SHOWERS
INCREASE IN COVERAGE AFTER ABOUT 16Z...SPREADING INLAND.
WIDESPREAD CLOUD COVER WILL LIMIT INSTABILITY SOMEWHAT BUT HEAVY
DOWNPOURS AND OCCASIONAL LIGHTNING IS EXPECTED WITH ANY STORMS
THIS AFTERNOON. DID LOWER MAXIMUM TEMPERATURES A COUPLE OF DEGREES
DUE TO THE EXTENSIVE CLOUD COVER.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
AS OF 345 AM SUNDAY...THE COASTAL TROUGH WILL GRADUALLY WORK INLAND
WITH HIGH PRES ANCHORED TO THE N WITH A CONTD MOIST E-NE FLOW ACRS
THE AREA. SCT ONGOING CONVECTION WANES DURG THE EVE HOURS WITH
LOSS OF DAYTIME HTG BECOMING GENERALLY WDLY SCT AFT MIDNIGHT.
PATCHY FOG AND STRATUS WILL LIKELY ONCE AGAIN DEVELOP LATE
TONIGHT. LOWS WILL RANGE FROM THE UPR 60S WELL INLAND TO THE LWR
AND MID 70S ACRS COASTAL AREAS.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
AS OF 225 AM SUN...MODELS IN GOOD AGREEMENT THROUGH MUCH OF THE
FORECAST PERIOD...WITH SOME DIFFERENCES NOTED LATE IN THE WEEK.
HIGH PRESSURE IN THE UPPER LEVELS THROUGH MIDWEEK. DEEP TROUGH ALONG
THE WEST COAST WILL LIFT NORTH OVER THE RIDGE AND INTO CANADA. AT
THE SURFACE HIGH PRESSURE TO THE NORTH WITH LOW PRESSURE TO THE
SOUTH WILL KEEP EAST AND NORTHEAST FLOW OVER EASTERN NORTH CAROLINA
INTO MONDAY. LOW PRESSURE TO THE SOUTH WILL DISSIPATE THROUGH THE
DAY ON MONDAY...ALLOWING THE HIGH PRESSURE AXIS TO DROP SOUTH...
BRINGING OUR FLOW TO MORE SOUTHEASTERLY MONDAY NIGHT AND FINALLY
SOUTHWESTERLY TUESDAY NIGHT. THIS PATTERN WILL CONTINUE THROUGH
FRIDAY AS A FRONTAL SYSTEM APPROACHES FROM THE WEST.
MODELS DIVERGE STARTING FRIDAY AS ECMWF CLOSES AN UPPER LOW OFF OVER
THE MIDWEST WHILE THE GFSENS KEEPS AN OPEN WAVE. AT THE SURFACE
MODELS DO AGREE ON KEEPING THE FRONTAL BOUNDARY JUST TO THE WEST OF
THE FORECAST AREA THROUGH SATURDAY.
EVEN WITH RIDGE ALOFT OVER THE AREA...SOME ENERGY IN THE MID LEVELS
COMBINED WITH LOW LEVEL ONSHORE FLOW WILL ALLOW UNSETTLED WEATHER
INTO TUESDAY WITH HIGHEST POPS ALONG THE COAST WITH THE DEEPEST
MOISTURE. AS SURFACE FLOW BECOMES WEST AND SOUTHWESTERLY THROUGH THE
REMAINDER OF THE WEEK...WILL HAVE INCREASED CHANCES.
HIGH TEMPERATURES EXPECTED TO BE IN THE MIDDLE TO UPPER 80S WITH
LOWS IN THE UPPER 60S TO LOWER 70S THROUGH THE WEEK.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
SHORT TERM /THROUGH 12Z MONDAY/...
AS OF 630 AM SUNDAY...MVFR CIGS LIKELY ACRS TAF SITES THRU ABT
16Z. HIGH PRES WILL BUILD IN FROM THE NORTH THROUGH THE PERIOD
WITH WINDS ELY 10 KT OR LESS. A MOIST ONSHORE FLOW AND UPR LEVEL
SHTWV ENERGY WILL CONTINUE TO BRING CHANCES FOR SHOWERS AND A FEW
THUNDERSTORMS ACROSS AT THE TAF SITES MAINLY DURG THE AFTN/EARLY
EVE DURG MAX HTG AFT 16Z. WILL HAVE MENTION VCSH THIS MORN AND
LATE EVE...AND VCTS FM 18Z- 00Z.
SUB VFR CIGS AND VSBYS WILL BE POSSIBLE AGAIN LATE TONIGHT WITH
MOIST ELY FLOW CONTG AND LIGHTER NE-E FLOW.
LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 238 AM SUN...OCCASIONAL SUBVFR CONDITIONS EXPECTED THROUGH THE
FORECAST PERIOD WITH SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS...MAINLY DURING THE AFTERNOON AND EVENING HOURS. MAY
ALSO SEE SUBVFR IN THE PREDAWN HOURS EACH DAY WITH FOG.
&&
.MARINE...
SHORT TERM /THROUGH TONIGHT/...
AS OF 950 AM SUNDAY...HAVE DROPPED SMALL CRAFT ADVISORY OVER THE
FAR NORTHERN WATERS AS SEAS HAVE FALLEN TO 5 FEET AT BEST OVER
THAT AREA. NE WINDS SHOULD PERSIST THIS AFTERNOON AT 15 KNOTS OR
LESS WITH SEAS 3 TO 5 FEET. NE-E WINDS WILL DIMINISH TO 10-15 KT
BY TONIGHT WITH SEAS EXPECTED TO RANGE 2-5 FT...HIGHEST SEAS ACRS
THE NRN COASTAL WATERS.
LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 245 AM SUN...EAST AND NORTHEASTERLY FLOW OVER THE NORTH
CAROLINA COASTAL WATERS MONDAY WITH HIGH PRESSURE TO THE NORTH AND
LOW PRESSURE TO THE SOUTH. AS THE LOW PRESSURE DISSIPATES...HIGH
PRESSURE AXIS WILL DROP SOUTH TURNING FLOW TO SOUTH AND
SOUTHEASTERLY TUESDAY. FRONTAL SYSTEM WILL APPROACH...BUT WILL
REMAIN WELL TO THE WEST...DURING THE LATER PARTS OF THE FORECAST
PERIOD...WITH FLOW BECOMING SOUTHWESTERLY TUESDAY NIGHT AND
REMAINING THROUGH THURSDAY. RELATIVELY LOOSE GRADIENT WILL KEEP
SPEEDS 10 TO 15 KNOTS WITH SEAS 3 TO 4 FEET.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JAC
NEAR TERM...CTC
SHORT TERM...JAC
LONG TERM...CCG/CTC
AVIATION...JAC/CCG
MARINE...JAC/CCG/CTC
AREA FORECAST DISCUSSION
NWS RALEIGH NC
803 AM EDT SUN SEP 6 2015
.SYNOPSIS...AN UPPER LEVEL LOW WILL RETROGRADE FROM THE SOUTHEAST
COAST TO THE NORTHERN GULF OF MEXICO TONIGHT...THEN STALL NEAR THE
TEXAS GULF COAST THROUGH MID-WEEK.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 330 AM SUNDAY...
OVERVIEW: A BROAD H3 LOW...CENTERED IN VICINITY OF CHARLOTTE AT 06Z
THIS MORNING...WILL RETROGRADE SLOWLY SOUTHWEST TOWARD THE NORTHERN
GULF OF MEXICO TODAY/TONIGHT. SMALL AMPLITUDE WAVES ROTATING
CYCLONICALLY AROUND THE EASTERN PERIPHERY OF THE UPPER LOW WILL
TRACK NORTHWARD ALONG THE GA/SC COAST AND WESTWARD INTO THE
CAROLINAS. A SFC RIDGE EXTENDING SOUTHWESTWARD THROUGH THE MID-
ATLANTIC INTO THE WESTERN CAROLINAS WILL PERSIST THROUGH TONIGHT.
MEANWHILE...AN EASTERLY /ONSHORE/ 925-850 MB FLOW WILL ADVECT RICH
LOW-LEVEL MOISTURE INLAND INTO THE CAROLINAS THROUGHOUT THE
DAY...WITH PWAT VALUES INCREASING INTO THE 1.75-2.00" RANGE THIS
AFTERNOON.
PRECIP: CONVECTION HAS BLOSSOMED OFFSHORE THE CAROLINA COAST THE
PAST FEW HRS IN ASSOC/W DPVA ATTENDANT SMALL AMPLITUDE SHORTWAVE
ENERGY ROUNDING THE EASTERN PERIPHERY OF THE H3 LOW CENTERED NEAR
CHARLOTTE NC. A DRY/STABLE AIRMASS WAS NOTED IN CENTRAL NC AT 06Z
THIS MORNING...IN ASSOC/W NOCTURNAL COOLING AND A DRY 925-850 MB
AIRMASS THAT ADVECTED SOUTHWEST INTO CENTRAL NC YESTERDAY EVENING.
AIRMASS MODIFICATION /DESTABILIZATION/ IS ALREADY UNDERWAY IN
COASTAL NORTH CAROLINA WHERE EASTERLY LOW-LEVEL FLOW HAS ADVECTED A
HIGHER THETA-E AIRMASS (925 MB DEWPOINTS ~18C) ONSHORE. THIS AIRMASS
IS EXPECTED TO PROGRESS INTO THE COASTAL PLAIN BY ~12Z...HWY 1
CORRIDOR BY 18Z THIS AFTERNOON...AND WESTERN PIEDMONT BY MID/LATE
AFTERNOON. SHORTWAVE ENERGY ROUNDING THE EASTERN PERIPHERY OF THE
UPPER LOW AT 07Z MAY OUTPACE THE UNSTABLE AIRMASS ADVECTING WESTWARD
TOWARD CENTRAL NC...AND CONVECTION CURRENTLY ALONG THE COAST APPEARS
UNLIKELY TO PROPAGATE AND/OR DEVELOP INLAND PRIOR TO SUNRISE.
HOWEVER...ADDITIONAL SHORTWAVE ENERGY PROGRESSING INTO THE AREA
BETWEEN 15-21Z WILL ENCOUNTER RICHER LOW-LEVEL MOISTURE (IN ADDITION
TO FAV DIURNAL TIMING)...AND SCATTERED TO WIDESPREAD CONVECTION IS
LIKELY TO PROPAGATE AND/OR DEVELOP WESTWARD INTO CENTRAL NC DURING
THAT TIME. EXPECT CHANCES FOR CONVECTION TO WANE THIS EVENING IN
ASSOC/W NOCTURNAL STABILIZATION AND SUBSIDENCE IN THE WAKE OF
SHORTWAVE ENERGY TRACKING WEST/SW ALONG THE NORTHERN PERIPHERY OF
THE UPPER LOW RETROGRADING TO THE NORTHERN GULF COAST.
HAZARDS: DEEP LAYER SHEAR WILL REMAIN INSUFFICIENT FOR CONVECTIVE
ORGANIZATION ASIDE FROM THE BRIEF MULTICELLULAR VARIETY (PRIMARILY
ALONG OUTFLOW). INCREASED MOISTURE ASSOC/W PERSISTENT ONSHORE FLOW
SHOULD RESULT IN MARGINAL DCAPE...THOUGH THE LATEST RAP GUIDANCE
INDICATES A REGION OF MODERATE DCAPE (750-1000 J/KG) PROGRESSING
INLAND INTO EASTERN NC BY LATE MORNING AND THE COASTAL PLAIN THIS
AFTERNOON. IF THIS OCCURS AS THE RAP SUGGESTS...EVAP COOLING AND
PRECIP LOADING WITHIN HIGHLY REFLECTIVE/ELEVATED CORES ATTENDANT
DEEP CONVECTION WOULD BE MORE LIKELY TO SUPPORT A POTENTIAL FOR
ISOLD SVR DOWNBURSTS. -VINCENT
&&
.SHORT TERM /MONDAY AND MONDAY NIGHT/...
AS OF 330 AM SUNDAY...
PRECIP CHANCES WILL DECREASE ON MONDAY AS THE UPPER LOW PROGRESSES
TO THE NORTHERN GOMEX AND SHORTWAVE ENERGY ROUNDING THE
EASTERN/NORTHERN PERIPHERY OF THE LOW REMAINS SOUTH/SOUTHWEST OF
CENTRAL NC...THOUGH SOME POTENTIAL FOR DIURNAL CONVECTION MAY
PERSIST IN THE COASTAL PLAIN...IN CLOSER VICINITY TO MORE FAVORABLE
MOISTURE AND WEAK LOW-LEVEL CONVERGENCE ATTENDANT AN INVERTED TROUGH
NEAR THE CAROLINA COAST. -VINCENT
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
AS OF 245 AM SUNDAY...
IT APPEARS THAT THE CHANCES OF MUCH NEEDED RAINFALL SHOULD INCREASE
ACROSS THE REGION BEGINNING WEDNESDAY... LASTING THROUGH FRIDAY AND
POSSIBLY INTO THE WEEKEND.
MOST MODEL SOLUTIONS DEPICT AN UPPER LEVEL LONG WAVE TROUGH TO MOVE
FROM THE NORTHERN PLAINS TO THE GREAT LAKES AND OHIO VALLEY MID TO
LATE WEEK. WITH THE UPPER RIDGE PLANTED OVER THE SOUTHEASTERN UNITED
STATES EXPECTED TO GRADUALLY BE BUMPED EASTWARD INTO THE WESTERN
ATLANTIC... A DEEP S-SW FLOW WILL BRING PLENTY OF GULF OF MEXICO
MOISTURE NORTHWARD INTO THE MEAN FRONTAL BOUNDARY. ONE FRONT IS
FORECAST TO WASH OUT OR STALL NEAR THE CENTRAL APPALACHIANS
WEDNESDAY WITH THE MAIN FRONT FORECAST TO APPROACH THE REGION FROM
THE WEST FRIDAY OR SATURDAY. THIS WOULD MEAN AN INCREASING CHANCE OF
MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS BEGINNING
WEDNESDAY. SHOWERS AND THUNDERSTORMS SHOULD BECOME MORE NUMEROUS AND
OCCUR ANY TIME OF THE DAY/NIGHT BY THURSDAY INTO SATURDAY.
HIGHS SHOULD REMAIN SUMMER-LIKE 85-90 WED... THEN LOWER INTO THE
LOWER TO MID 80S BY FRI-SAT. LOWS SHOULD GENERALLY BE IN THE 65-70
RANGE OR EVEN WARMER BEFORE THE FRONT ARRIVES LATE WEEK.
&&
.AVIATION /12Z SUNDAY THROUGH FRIDAY/...
AS OF 745 AM SUNDAY...
24-HR TAF PERIOD: MVFR CEILINGS ASSOC/W A MOIST ONSHORE FLOW WILL
AFFECT EASTERN TERMINALS (RDU/FAY/RWI) THIS MORNING. SUB-VFR
CEILINGS ARE UNLIKELY TO DEVELOP FURTHER WEST AT INT/GSO. CEILINGS/
VISBYS WILL LIFT AND SCATTER TO VFR BETWEEN 12-16Z IN ASSOC/W
DIURNAL HEATING. SHOWERS/STORMS DEVELOPING IN VICINITY OF CAPE FEAR
WILL GRADUALLY TRACK AND/OR DEVELOP FURTHER INLAND TO THE WEST/WNW
TODAY...AND COULD AFFECT THE FAY TERMINAL BY NOON. SCATTERED
SHOWERS/STORMS ARE LIKELY TO AFFECT MOST OR ALL TERMINALS THIS
AFTERNOON AS AN UPPER LEVEL LOW RETROGRADES SOUTHWESTWARD FROM THE
CAROLINAS TOWARD THE NORTHERN GOMEX. OUTSIDE OF CONVECTION...VFR
CONDITIONS WILL PREVAIL THIS AFT/EVE AND EARLY TONIGHT. DENSE FOG OR
IFR/LIFR STRATUS WILL BE POSSIBLE BY THE END OF THE TAF PERIOD EARLY
MONDAY MORNING... PARTICULARLY AT THE RDU/FAY/RWI TERMINALS.
LOOKING AHEAD: AN UNSETTLED PATTERN WILL PERSIST THROUGH MID-LATE
WEEK WITH ABOVE NORMAL CHANCES FOR CONVECTION IN ADDITION TO MORNING
STRATUS OR FOG. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM...VINCENT
LONG TERM...BADGETT
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
930 AM CDT SUN SEP 6 2015
.UPDATE...
ISSUED AT 930 AM CDT SUN SEP 6 2015
HAVE BUMPED UP POPS A BIT ACROSS TEH NORTHERN RRV AND NORTHWEST MN
THROUGH THIS FORENOON AND EARLY AFTERNOON. SCATTERED SHOWERS AND
ISOLD THUNDERSTORMS HAVE SPREAD ACROSS THE NORTHERN RRV AND ARE
MOVING INTO THE CENTRAL RRV ATTM.
UPDATE ISSUED AT 612 AM CDT SUN SEP 6 2015
THE FIRST WAVE OF SHOWERS AND STORMS IS EXITING PEMBINA AND
CAVALIER COUNTIES INTO MANITOBA...WITH MORE DEVELOPMENT ALONG
THAT SW-NE TRACK OVER BENSON AND RAMSEY. MORE DEVELOPMENT IS
BEGINNING ACROSS KIDDER...FOSTER AND EDDY. WILL NEED TO ADD SCT
TSRA ALONG THE I 94 ROUTE INTO THE VALLEY...BUT WITH NE MOTION
WILL NOT TAKE INTO THE CENTRAL AND SOUTHERN VALLEY. DAY SHIFT CAN
MONITOR AND ADJUST AS NEEDED. ALSO CLEARED POPS FROM EASTERN
COUNTIES FOR THE MORNING AS THIS PRECIP HAS MOVED INTO NE MN.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 340 AM CDT SUN SEP 6 2015
FORECAST CHALLENGE FOR THE SHORT TERM WILL BE ONGOING
CONVECTION EXITING THE CWA TO THE EAST AND ENTERING THE CWA
TO THE WEST. THE WESTERN ACTIVITY IS ASSOCIATED WITH A SFC
TROF/FRONT ROUGHLY ALONG A NORTHGATE TO MINOT TO STEELE TO
ASHLEY LINE...WITH MAJORITY OF CONVECTION IN N CNTRL ND.
HRRR HAS A DECENT HANDLE ON WRN ACTIVITY BUT MAY BE A BIT TOO
FAR WEST...IN GENERAL CLIPPING THE FAR NORTHWESTERN PORTION OF
THE CWA. WILL FOLLOW HRRR GUIDANCE BUT BRING CATEGORICAL POPS
FURTHER EAST AND JUST WEST OF DEVILS LAKE. HRRR DOES LIFT THIS
ACTIVITY OUT OF CONUS AND INTO MB BY 13Z.
FOCUS FOR AFTERNOON WILL BE HOW MUCH LOW LEVEL CLOUD CAN SCOUR
OUT AND TIMING FRONT INTO NW AND W CNTRL MN...WHICH SHOULD ARRIVE
IN FAR EASTERN ZONES NEAR PEAK HEATING. THE NAM CONTINUES TO SHOW
MUCAPES OF AROUND 1500 TO 2200 J/KG (HRRR VALUES ARE SIGNIFICANTLY
LESS) WITH BULK SHEAR AROUND 40 KTS IN THE HIGHEST CAPE AND
SLIGHTLY HIGHER BEHIND THE SFC BOUNDARY. CURRENT SPC SLIGHT RISK
AREA IS ALONG FAR EASTERN COUNTIES ALONG AND AHEAD OF
FRONT...HOWEVER NAM TIMING WOULD DRAG THE SEVERE POTENTIAL BACK
FURTHER INTO OTTER TAIL COUNTY ALONG THE SOUTHERN END OF THE
BOUNDARY. WILL MAKE LITTLE CHANGE TO PREV POPS FOR AFTN HOURS.
FRONT SHOULD EXIT CWA BY EVENING AND DRY WEATHER EXPECT FROM MID
EVENING THROUGH THE OVERNIGHT PERIOD...WITH COOL AND DRY AIR IN
THE MID 40S MOVING INTO NW ZONES.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 340 AM CDT SUN SEP 6 2015
MON NIGHT...SW FLOW ALOFT TURNING MORE ZONAL BY TUE MORNING.
A WEAK VORT MAX AND SWT ASSOCIATED WITH UPPER LOW OVER NRN
MANITOBA BRINGING A CHANCE OF WEAK SHOWERS IN THE FAR
NORTHEAST...AND WILL KEEP LOW POPS PER GOOD AGREEMENT BETWEEN
ECMWF/GFS/NAM SOLUTIONS. MAJORITY OF AREA HOWEVER WILL BE DRY
WITH MUCH COOLER AIR ENTERING FAR NW...OVERNIGHT LOWS IN THE
MID 40S AROUND LANGDON.
TUE AND TUE NIGHT...ZONAL FLOW WITH MODELS SHOWING A SFC LOW
ENTERING NORTH DAKOTA TUE NIGHT...ALTHOUGH SIGNIFICANT DIFFERENCE
ON TRACK OF LOW WITH NAM SHOWING SFC LOW OVER SRN SASK AT 12Z WED
COMPARED TO ECMWF IN CNTRL ND AND MORE BULLISH WITH SHOWERS. WILL
BRING LOW POPS INTO DVL BASIN BUT CONFIDENCE IS LOW ATTM.
WEDNESDAY THROUGH SATURDAY...MODELS GENERALLY AGREE WITH THE
OVERALL PATTERN PLACING THE REGION ON THE SOUTHERN END OF A STRONG
UPPER LOW PROPAGATING THROUGH CANADA. MOSTLY A DRY PERIOD...ALTHOUGH
ANY SHORTWAVES ROTATING THROUGH COULD LEAD TO BRIEF SHOWER CHANCES
(BEST CHANCES WED AND FRI). TEMPERATURES A BIT BELOW NORMAL
TRANSITIONING BACK TOWARD NEAR NORMAL VALUES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 612 AM CDT SUN SEP 6 2015
SHRA CURRENTLY APPROACHING DVL WITH CLUSTER OF TSRA BEHIND IT.
WILL CONTINUE TSRA ON 12Z TAFS...ENDING AFTER 14Z AS LINE SHOULD
BE THROUGH BY THEN. CLUSTER OF STORMS OVER FOSTER COUNTY SHOULD
ARRIVE 14Z TO GFK...IF THEY HOLD TOGETHER. HAVE ALSO ADDED VCTS TO
GFK FOR MID MORNING. VICINITY TS AT TVF AND ONSTATION TS AT BJI
EXPECTED TO OCCUR THIS AFTN AS FRONT MOVES INTO MN. AREAS OF LOW
VSBYS AND CIGS MAINLY ALONG AND NORTH OF HWY 2 CORRIDOR WILL ALSO
FLUCTUATE AS TS MOVE INTO AREAS WITH IMPROVED VSBYS AND CIGS AFTER
SHOWERS PASS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...GUST
SHORT TERM...SPEICHER
LONG TERM...TG/SPEICHER
AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
611 AM CDT SUN SEP 6 2015
.UPDATE...
ISSUED AT 612 AM CDT SUN SEP 6 2015
THE FIRST WAVE OF SHOWERS AND STORMS IS EXITING PEMBINA AND
CAVALIER COUNTIES INTO MANITOBA...WITH MORE DEVELOPMENT ALONG
THAT SW-NE TRACK OVER BENSON AND RAMSEY. MORE DEVELOPMENT IS
BEGINNING ACROSS KIDDER...FOSTER AND EDDY. WILL NEED TO ADD SCT
TSRA ALONG THE I 94 ROUTE INTO THE VALLEY...BUT WITH NE MOTION
WILL NOT TAKE INTO THE CENTRAL AND SOUTHERN VALLEY. DAY SHIFT CAN
MONITOR AND ADJUST AS NEEDED. ALSO CLEARED POPS FROM EASTERN
COUNTIES FOR THE MORNING AS THIS PRECIP HAS MOVED INTO NE MN.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 340 AM CDT SUN SEP 6 2015
FORECAST CHALLENGE FOR THE SHORT TERM WILL BE ONGOING
CONVECTION EXITING THE CWA TO THE EAST AND ENTERING THE CWA
TO THE WEST. THE WESTERN ACTIVITY IS ASSOCIATED WITH A SFC
TROF/FRONT ROUGHLY ALONG A NORTHGATE TO MINOT TO STEELE TO
ASHLEY LINE...WITH MAJORITY OF CONVECTION IN N CNTRL ND.
HRRR HAS A DECENT HANDLE ON WRN ACTIVITY BUT MAY BE A BIT TOO
FAR WEST...IN GENERAL CLIPPING THE FAR NORTHWESTERN PORTION OF
THE CWA. WILL FOLLOW HRRR GUIDANCE BUT BRING CATEGORICAL POPS
FURTHER EAST AND JUST WEST OF DEVILS LAKE. HRRR DOES LIFT THIS
ACTIVITY OUT OF CONUS AND INTO MB BY 13Z.
FOCUS FOR AFTERNOON WILL BE HOW MUCH LOW LEVEL CLOUD CAN SCOUR
OUT AND TIMING FRONT INTO NW AND W CNTRL MN...WHICH SHOULD ARRIVE
IN FAR EASTERN ZONES NEAR PEAK HEATING. THE NAM CONTINUES TO SHOW
MUCAPES OF AROUND 1500 TO 2200 J/KG (HRRR VALUES ARE SIGNIFICANTLY
LESS) WITH BULK SHEAR AROUND 40 KTS IN THE HIGHEST CAPE AND
SLIGHTLY HIGHER BEHIND THE SFC BOUNDARY. CURRENT SPC SLIGHT RISK
AREA IS ALONG FAR EASTERN COUNTIES ALONG AND AHEAD OF
FRONT...HOWEVER NAM TIMING WOULD DRAG THE SEVERE POTENTIAL BACK
FURTHER INTO OTTER TAIL COUNTY ALONG THE SOUTHERN END OF THE
BOUNDARY. WILL MAKE LITTLE CHANGE TO PREV POPS FOR AFTN HOURS.
FRONT SHOULD EXIT CWA BY EVENING AND DRY WEATHER EXPECT FROM MID
EVENING THROUGH THE OVERNIGHT PERIOD...WITH COOL AND DRY AIR IN
THE MID 40S MOVING INTO NW ZONES.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 340 AM CDT SUN SEP 6 2015
MON NIGHT...SW FLOW ALOFT TURNING MORE ZONAL BY TUE MORNING.
A WEAK VORT MAX AND SWT ASSOCIATED WITH UPPER LOW OVER NRN
MANITOBA BRINGING A CHANCE OF WEAK SHOWERS IN THE FAR
NORTHEAST...AND WILL KEEP LOW POPS PER GOOD AGREEMENT BETWEEN
ECMWF/GFS/NAM SOLUTIONS. MAJORITY OF AREA HOWEVER WILL BE DRY
WITH MUCH COOLER AIR ENTERING FAR NW...OVERNIGHT LOWS IN THE
MID 40S AROUND LANGDON.
TUE AND TUE NIGHT...ZONAL FLOW WITH MODELS SHOWING A SFC LOW
ENTERING NORTH DAKOTA TUE NIGHT...ALTHOUGH SIGNIFICANT DIFFERENCE
ON TRACK OF LOW WITH NAM SHOWING SFC LOW OVER SRN SASK AT 12Z WED
COMPARED TO ECMWF IN CNTRL ND AND MORE BULLISH WITH SHOWERS. WILL
BRING LOW POPS INTO DVL BASIN BUT CONFIDENCE IS LOW ATTM.
WEDNESDAY THROUGH SATURDAY...MODELS GENERALLY AGREE WITH THE
OVERALL PATTERN PLACING THE REGION ON THE SOUTHERN END OF A STRONG
UPPER LOW PROPAGATING THROUGH CANADA. MOSTLY A DRY PERIOD...ALTHOUGH
ANY SHORTWAVES ROTATING THROUGH COULD LEAD TO BRIEF SHOWER CHANCES
(BEST CHANCES WED AND FRI). TEMPERATURES A BIT BELOW NORMAL
TRANSITIONING BACK TOWARD NEAR NORMAL VALUES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 612 AM CDT SUN SEP 6 2015
SHRA CURRENTLY APPROACHING DVL WITH CLUSTER OF TSRA BEHIND IT.
WILL CONTINUE TSRA ON 12Z TAFS...ENDING AFTER 14Z AS LINE SHOULD
BE THROUGH BY THEN. CLUSTER OF STORMS OVER FOSTER COUNTY SHOULD
ARRIVE 14Z TO GFK...IF THEY HOLD TOGETHER. HAVE ALSO ADDED VCTS TO
GFK FOR MID MORNING. VICINITY TS AT TVF AND ONSTATION TS AT BJI
EXPECTED TO OCCUR THIS AFTN AS FRONT MOVES INTO MN. AREAS OF LOW
VSBYS AND CIGS MAINLY ALONG AND NORTH OF HWY 2 CORRIDOR WILL ALSO
FLUCTUATE AS TS MOVE INTO AREAS WITH IMPROVED VSBYS AND CIGS AFTER
SHOWERS PASS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...SPEICHER
SHORT TERM...SPEICHER
LONG TERM...TG/SPEICHER
AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
628 AM CDT SUN SEP 6 2015
.AVIATION UPDATE...
12Z TAF DISCUSSION.
PATCHY FOG WILL BRING MVFR/IFR VIS TO CSV EARLY IN THE TAF
PERIOD...BUT OTHERWISE SCT CUMULUS EXPECTED TODAY WITH LIGHT SOUTH
TO SOUTHEAST WINDS. HRRR MODEL INDICATES WIDELY SCT -SHRA/-TSRA
AGAIN THIS AFTERNOON...AND WILL MENTION VCTS AT CSV AND VCSH AT
BNA BASED ON MODEL TRENDS.
SHAMBURGER
&&
.PREV DISCUSSION... /ISSUED 247 AM CDT SUN SEP 6 2015/
DISCUSSION...
ISOLATED CONVECTION DEVELOPED YESTERDAY AFTERNOON ACROSS MIDDLE
TENNESSEE...AND PRODUCED DECENT RAINFALL WITH SOME PRETTY STRONG
DOWNBURST WINDS. MODEL SOUNDINGS YESTERDAY DID SHOW DECENT CAPE
AROUND 2000 J/KG OR SO...AND HAD VERY LITTLE SHEAR. NOT TOO
SURPRISED THAT A FEW CELLS DID DEVELOP...AND COLLAPSED PRETTY
QUICKLY. ATMOSPHERIC SETUP TODAY IS SIMILAR TO THE PAST FEW
DAYS...BUT THIS TIME THERES JUST A BIT MORE MOISTURE IN THE MID
LEVELS THANKS TO THE UPPER LOW SLIDING FURTHER SOUTH AND GIVING
THE REGION A LITTLE MORE FAVORABLE EAST TO NORTHEAST MOISTURE FLOW
RATHER THAN DUE NORTH DRYNESS FROM THE PAST FEW DAYS. THIS MAY
INCREASE CHANCES SLIGHTLY FOR THE REST OF THE CWA...BUT KEPT MOST
OF MIDDLE TENNESSEE IN SCHC CATEGORY FOR PRECIP CHANCES. MUCAPE
VALUES ARE SLIGHTLY LESS THAN WHAT WAS FORECASTED YESTERDAY...BUT
STILL IN THE 1500-2000 J/KG RANGE AND COULD PUT DOWN SOME DECENT
RAINFALL AND WINDS IN A SHORT TIME SHOULD CELLS DEVELOP. WITH THE
CONTINUED ABSENCE OF SHEAR THOUGH THE CONVECTION SHOULD DIE OUT
RELATIVELY QUICK.
ON MONDAY AND TUESDAY THE UPPER LOW SLIDES TO OUR SOUTH...AND FOR
THE MOST PART SHOULD KEEP THINGS DRY OVER THE AREA. KEPT MENTION
OF SHOWERS AND THUNDERSTORMS IN FOR THE PLATEAU DURING THE
AFTERNOON HOURS BUT AGAIN ISOLATED CELLS ARE NOT OUT OF THE
QUESTION FOR THE REST OF THE AREA.
WEDNESDAY THROUGH FRIDAY STILL LOOKS TO BE THE BEST SHOT AT
RAINFALL FOR THE AREA AS THE UPPER TROUGH APPROACHES THE AREA. THE
ECMWF AND GFS ARE LINING UP MUCH BETTER THAN THE PAST FEW RUNS AND
HAVE THE TROUGH AXIS CROSSING THROUGH THE REGION THURSDAY
AFTERNOON ROUGHLY IN PHASE. THE ECMWF IS STILL A LITTLE FAST WITH
THE COLD FRONT...BRINGING IT INTO THE AREA LATE THURSDAY MORNING
AND THE GFS IS LATER THURSDAY AFTERNOON. BOTH MODELS HAVE A
SIMILAR QPF SOLUTION FOR THURSDAY...SO WENT AHEAD AND PUT IN SOME
LIKELY POPS FOR THURSDAY AFTERNOON. THE GFS IS NOW QUICKER TO DRY
OUT THE POST FRONTAL AIRMASS OVER THE ECMWF...SO BY FRIDAY NIGHT
THE SYSTEM COULD BE OUT OF THE AREA. COULD BE SOME TRAILING
CHANCES FOR PRECIP SO HAVE SCHC POPS IN FOR SATURDAY AND SUNDAY.
ANOTHER AGREEMENT BETWEEN MODELS IS THE UNSEASONABLY COOLER
AIRMASS THAT FOLLOWS THE FRONT FOR NEXT WEEKEND. 850MB TEMPS ARE
BETWEEN 10C-14C OVER MIDDLE TENNESSEE...AND WHEN COMBINED WITH
NORTHERLY FLOW...HIGH TEMPERATURES MAY ONLY BE IN THE 70S ON
SATURDAY AND SUNDAY. FORECASTED LOW TEMPS SATURDAY NIGHT ARE
CURRENTLY IN THE 50S. THE ECMWF AND GFS DIFFER A BIT FOLLOWING
NEXT WEEKEND IN REGARDS TO THE UPPER FLOW PATTERN...BUT THEY AGREE
ON KEEPING THE COOLER TEMPS OVER THE REGION SO HIGHS IN THE 90S
MAY BE ABSENT FROM THE LONG TERM FORECAST FOLLOWING NEXT WEEKEND.
AVIATION UPDATE...
06Z TAFS...FOG IS EXPECTED LATE TONIGHT THROUGH DAYBREAK...MAINLY
MVFR AT BNA AND CKV. CSV IS LIKELY TO HAVE PERIODS OF LIFR. FOG
WILL END BY 14Z...THEN VFR CONDITIONS ARE EXPECTED THROUGH SUNDAY.
ISOLD TSRA WILL DEVELOP IN THE AFTERNOON WITH VERY LIMITED
COVERAGE...SO NOT INCLUDING IN TAFS ATTM. WINDS WILL BE
LIGHT...MAINLY SE...THROUGH THE NEXT 24 HOURS.
13
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 91 70 91 70 / 20 10 10 10
CLARKSVILLE 92 68 91 68 / 20 10 10 10
CROSSVILLE 82 66 83 67 / 30 10 20 10
COLUMBIA 91 68 90 68 / 20 10 10 10
LAWRENCEBURG 89 68 88 68 / 20 10 10 10
WAVERLY 92 69 90 68 / 10 10 10 10
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
55
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1040 AM CDT SUN SEP 6 2015
.DISCUSSION...ONLY REAL CHANGE IS TO REMOVE THUNDERSTORMS BUT DID
KEEP THE SLIGHT CHANCE OF RAIN IN THE FORECAST (EXTENDED IT A TAD
TO THE WEST TOO). MORNING SOUNDING HAS 12C AT 700MB SO DO NOT
THINK WE WILL SEE ANY THUNDER TODAY. HOWEVER...RADAR IS SHOWING
SOME VERY WEAK ECHOES AND HRRR MODEL/NSSL 00Z RUN WAS SHOWING SOME
VERY WEAK CONVECTION DEVELOPING DURING THE DAY. AS A RESULT...
ALTHOUGH ANY RAIN WILL LIKELY BE TRACE AMOUNTS (OR BE VERY
ISOLATED WITH COVERAGE 10 PERCENT AT BEST)...DECIDED TO KEEP THE
MENTION OF RAIN. OTHERWISE...FORECAST IS UN-DERAILED AND THUS WILL
FOREGO MAKING MODIFICATIONS AT THIS TIME WHICH MAY LIKELY NOT BE
NECESSARY ON THE AFTERNOON PACKAGE. UPDATED PRODUCTS OUT.
&&
.PREV DISCUSSION... /ISSUED 637 AM CDT SUN SEP 6 2015/
DISCUSSION...UPDATED FOR 12Z AVIATION.
AVIATION...LOW CLOUDS AND PATCHY FOG WILL CONTINUE AT THE
ALI/VCT/LRD TERMINALS FOR THE NEXT HOUR OR TWO WITH VFR CONDITIONS
RETURNING THEREAFTER. PRECIP CHANCES ARE TOO LOW TO MENTION IN THE
FORECAST TODAY...AND WILL LEAVE OUT FOR NOW. WINDS WILL PICK UP
THIS AFTERNOON WITH GUSTS AT OR SLIGHTLY ABOVE 20 KNOTS. GUSTS
SHOULD SUBSIDE AROUND 01Z. MVFR CONDITIONS MAY RETURN LATE IN THE
FORECAST AT ALI/VCT WITH PATCHY FOG AND LOW CLOUDS AGAIN DEVELOP
AND HAVE INCLUDE MVFR CONDITIONS AFTER 09Z/10Z.
PREV DISCUSSION... /ISSUED 351 AM CDT SUN SEP 6 2015/
SHORT TERM (TODAY THROUGH MONDAY)...NEAR SURFACE MOISTURE AND
LIGHT WINDS LED TO SOME FOG DEVELOPING THIS MORNING. LOCATIONS
ACROSS THE EASTERN BRUSH COUNTRY INTO THE VICTORIA CROSSROADS WILL
BE MOST LIKELY TO EXPERIENCE FOGGY CONDITIONS. VSBYS COULD BE
REDUCED OVER A SHORT DISTANCE AND FALL TO A LESS THAN A MILE AT
TIMES. CONFIDENCE IS NOT HIGH ENOUGH FOR AN ADVISORY AT THIS TIME.
UPPER LEVEL RIDGE WILL REMAIN OVER THE REGION TODAY...WHICH SHOULD
KEEP MOST PLACES DRY. THE EXCEPTION COULD BE OVER THE GULF WATERS
INTO NORTHERN COASTAL BEND WHERE SOME ISOLATED SHOWERS/STORMS
COULD DEVELOP. HAVE INCLUDED A 10 POP WITH MENTION OF SHRA/TSRA
OVER THESE AREA...ALTHOUGH CONFIDENCE IS NOT THAT HIGH AT ALL.
VERY WARM CONDITIONS ARE EXPECTED ACROSS SOUTH TEXAS AGAIN TODAY
WITH HIGHS BETWEEN 100 AND 103 DEGREES OUT WEST AND LOWER/MID 90S
ACROSS THE EAST/NORTHEAST. HI INDEX VALUES WILL BE ELEVATED
TODAY...MAINLY IN THE 105 TO 109 RANGE...AND WILL BE ISSUING SPS
TO ADDRESS THE HI. MODELS PROG SLIGHTLY DEEPER MOISTURE ARRIVING
FROM THE EAST ON MONDAY...WHICH COULD RESULT IN SOME ISOLATED TO
SCATTERED CONVECTION ACROSS THE GULF WATERS AND NORTHEAST ZONES.
ABOVE NORMAL TEMPERATURES WILL PERSIST INTO MONDAY ACROSS THE
AREA.
LONG TERM (MONDAY NIGHT THROUGH SATURDAY)...A TRANSITIONING PERIOD
WILL EXIST BY MID WEEK AS THE MID LEVEL RIDGE SHIFTS WEST AND A MID
LEVEL TROUGH/LOW MOVES IN FROM THE EAST INTO THE WESTERN GULF.
COOLING MID LEVEL TEMPERATURES COMBINED WITH PWATS OF 1.7-1.9 INCHES
WILL ALLOW FOR ISOLATED SHOWER AND THUNDERSTORM ACTIVITY PRIMARILY
ACROSS THE EASTERN THIRD OF THE CWA THROUGH WEDNESDAY. IN THE
MEANTIME...THE MID LEVEL TROUGH MOVING ACROSS NORTHERN CANADA WILL
PUSH THE ASSOCIATED SURFACE COLD FRONT ACROSS THE CENTRAL PLAINS.
FURTHER AIDE FROM THE NW TO SE H25 FLOW ACROSS THE EASTERN HALF OF
THE U.S. SHOULD PUSH THE FRONT FARTHER SOUTH INTO TEXAS. GFS AND
EURO CONTINUE TO DISAGREE WITH TIMING AND POSITIONING OF THE FRONT
FROM THURSDAY AND ONWARD...BUT OVERALL CONTINUE TO SHOW PWATS
INCREASING TO 2+ INCHES ACROSS SOUTH TEXAS...LEADING TO AT LEAST
SCATTERED ACTIVITY HEADING INTO THURSDAY AND THROUGH THE EARLY PART
OF THE WEEKEND. FOR TEMPERATURES EARLY IN THE WEEK...WITH OVERALL
SOUTHEAST FLOW THROUGH AT LEAST H85...TEMPERATURES SHOULD BE ABLE TO
RESIDE ON THE COOL SIDE OF GUIDANCE FOR EASTERN ZONES IN THE LOW
90S...WHILE H85 MIXING AND DRYING ACROSS THE WESTERN BRUSH COUNTRY
SHOULD CONTINUE TEMPS AROUND THE 100 DEGREE MARK. TEMPERATURES FOR
THE LATTER PART OF THE WEEK WILL RELY HEAVILY ON CLOUD COVERAGE AND
RAIN CHANCES...HOWEVER DID SHOW A COOLING TREND INTO THE 80S FOR THE
END OF THE WORK WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 96 78 95 77 94 / 10 10 10 10 20
VICTORIA 96 76 95 74 94 / 10 10 20 10 20
LAREDO 103 79 102 78 101 / 0 0 10 10 10
ALICE 99 76 98 75 96 / 10 0 10 10 10
ROCKPORT 93 80 91 80 90 / 10 10 20 10 20
COTULLA 102 77 102 76 100 / 0 0 10 10 10
KINGSVILLE 98 77 97 76 96 / 10 0 10 10 10
NAVY CORPUS 91 80 90 79 90 / 10 10 20 10 20
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
GW/86...SHORT-TERM
AREA FORECAST DISCUSSION
NWS TUCSON AZ
910 AM MST SUN SEP 6 2015
.SYNOPSIS...EXPECT SCATTERED SHOWERS AND THUNDERSTORMS THROUGH
TUESDAY FOLLOWED BY DECREASING PRECIPITATION CHANCES DURING THE
LATTER PART OF THE UPCOMING WEEK. WARMER TEMPERATURES WILL OCCUR
TODAY...THEN NEAR NORMAL DAYTIME TEMPERATURES THIS WEEK.
&&
.DISCUSSION...IR/VISIBLE SATELLITE IMAGERY AND SURFACE OBSERVATIONS
INDICATED SUNNY SKIES TO MOSTLY SUNNY SKIES FROM TUCSON WWD INTO WRN
PIMA COUNTY AND SOUTH CENTRAL PINAL COUNTY. MEANWHILE...PARTLY
CLOUDY TO MOSTLY CLOUDY SKIES PREVAILED ACROSS EASTERN SECTIONS.
DEWPOINTS AT LOWER ELEVATIONS VALID 16Z RANGED FROM THE UPPER 50S-
MID 60S F...AND THESE TEMPS WERE NEARLY 2-6 DEGS F LOWER VERSUS 24
HOURS AGO. SURFACE TEMPS VALID 16Z WERE ABOUT 3-8 DEGS F WARMER
VERSUS THIS TIME SAT.
06/12Z KTWC SOUNDING TOTAL PRECIP WATER VALUE OF 1.53 INCHES WAS
DOWN NEARLY 0.10 INCH VERSUS 24 HOURS AGO. THE SOUNDING DEPICTED
ONLY A MODESTLY UNSTABLE ENVIRONMENT...WITH MUCAPE OF 842 J/KG.
06/12 UPPER AIR PLOTS DEPICTED A LARGE AREA OF HIGH PRESSURE ACROSS
THE CENTRAL/SRN CONUS PLAINS...AND A LOW AMPLITUDE TROUGH OVER THE
PACIFIC NW/NRN ROCKIES. MODERATE TO FAST SWLY FLOW PREVAILED ABOVE
700 MB ACROSS SE ARIZONA.
SHOWERS/TSTMS ARE EXPECTED TO DEVELOP DURING THE 18Z-20Z PERIOD
ACROSS THE WHITE MOUNTAINS...AND MAINLY NEAR THE MOUNTAINS IN SRN/
ERN COCHISE COUNTY AND SANTA CRUZ COUNTY. SEVERAL HRRR SOLUTIONS AND
THE 06/12Z NAM SUBSEQUENTLY FAVOR LOCALES SOUTH-TO-SOUTHEAST OF
TUCSON WITH THE BEST CHANCE FOR RAINFALL LATER THIS AFTERNOON AND
EVENING. THE NAM12 IN PARTICULAR PRODUCES SOME IMPRESSIVE QPF/S
ACROSS THE CHIRICAHUA MOUNTAINS IN ERN COCHISE COUNTY...AND FURTHER
WWD ACROSS THE HUACHUCA/PATAGONIA MOUNTAINS IN SWRN COCHISE/ERN
SANTA CRUZ COUNTIES. HOWEVER...HAVE NOTED THAT THE 06/12Z UNIV OF
ARIZONA WRF-NAM IS NOT AS IMPRESSIVE VERSUS THE NAM12...ALTHOUGH
STILL FAVORS AN AREA FROM SOUTH-TO-SOUTHEAST OF TUCSON WITH THE BEST
POTENTIAL FOR MEASURABLE RAINFALL LATER THIS AFTERNOON AND EVENING.
AT ANY RATE...THE OFFICIAL GRIDDED DATA POPS WERE INCREASED
GENERALLY 10-20 PERCENT FOR THIS AFTERNOON AND EVENING...
PARTICULARLY FROM TUCSON SOUTH-TO-SOUTHEAST TO THE INTERNATIONAL
BORDER. HAVE MAINTAINED AT LEAST A SLIGHT CHANCE OF SHOWERS/TSTMS
LATE TONIGHT MAINLY FROM TUCSON EAST AND SOUTH TO THE NEW MEXICO/
INTERNATIONAL BORDERS. HIGH TEMPS THIS AFTERNOON WILL GENERALLY
RANGE ABOUT 5-15 DEGS WARMER VERSUS TEMPS ACHIEVED SAT...DEPENDING
UPON LOCATION.
PLEASE REFER TO THE ADDITIONAL SECTIONS FOR FURTHER DETAIL.
&&
.AVIATION...VALID THRU 07/18Z.
PARTIAL CLEARING TREND THROUGH THE MORNING HOURS WITH SCT-BKN MID-
HIGH LEVEL CLOUDS ACROSS SOUTHEAST ARIZONA. ISOLD-SCT SHRA/TSRA
DEVELOPING MAINLY SOUTH OF KTUS AFTER NOON...THEN INCREASING
COVERAGE AREA-WIDE AFTER 06/21Z WITH STORMS HANGING ON THROUGH THE
LATE EVENING HOURS. BRIEF MVFR CONDITIONS WITH WIND GUST OF 35-45
KTS WITH STRONGER TSRA...OTHERWISE NORMAL DIURNAL WIND TRENDS.
AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...THERE WILL BE ENOUGH MOISTURE AROUND FOR A CHANCE OF
MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS THROUGH MOST
OF THE COMING WEEK. BRIEF STRONG...GUSTY AND ERRATIC WINDS ARE
EXPECTED WITH THE STRONGER THUNDERSTORMS. OTHERWISE...20-FOOT WINDS
WILL BE MAINLY TERRAIN DRIVEN AND LESS THAN 15 MPH.
&&
.PREV DISCUSSION /235 AM MST/...TONIGHT COULD BE VERY INTERESTING...
ESPECIALLY ACROSS COCHISE COUNTY AS THE 00Z/06Z NAM AND BOTH U OF A
WRFNAM/WRKGFS MOVE A WEAK UPPER LEVEL DISTURBANCE ACROSS NERN SONORA
MEXICO AND THEN INTO COCHISE COUNTY. IF THESE MODELS ARE CORRECT...
AREAS SE OF TUCSON COULD SEE ISOLD MODERATE TO HEAVY SHOWERS WITH
EMBEDDED THUNDERSTORMS. WITH THIS IN MIND...HAVE INCREASED POPS AND
QPF VALUES SE OF TUCSON...ESPECIALLY ACROSS COCHISE COUNTY.
LABOR DAY...ISOLATED TO SCATTERED AFTERNOON AND EVENING STORMS WITH
SLIGHTLY WARMER HIGH TEMPERATURES.
TUESDAY...FLOW ALOFT STARTS TO BECOME MORE WESTERLY WITH UPPER HIGH
MOVING WEST ACROSS NRN MEXICO. WILL MAINTAIN SLIGHT CHANCE TO CHANCE
TYPE POPS IN THE FORECAST.
THE POSITION OF THE HIGH OVER NRN MEXICO WILL KEEP DEEPER TROPICAL
MOISTURE FROM TROPICAL STORM LINDA FROM BEING ADVECTED INTO SE
ARIZONA AS IT MOVES WEST OF BAJA CALIFORNIA. SO STARTING WEDNESDAY
AND CONTINUING INTO NEXT SATURDAY...EXPECT ONLY A SLIGHT CHANCE OF
AFTERNOON/EVENING STORMS ACROSS THE AREA WITH HIGHS NEAR OR SLIGHTLY
ABOVE NORMAL.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
DISCUSSION...FRANCIS
AVIATION/FIRE WEATHER...MEYER
AREA FORECAST DISCUSSION
NWS DES MOINES IA
305 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...06/18Z
ISSUED AT 1256 PM CDT SUN SEP 6 2015
WITH THE COLD FRONT APPROACHING IOWA THIS EVENING...CONDITIONS
WILL CONTINUE TO DETERIORATE WITH INCREASING AREAL COVERAGE OF
THUNDERSTORMS FROM 00 TO 06Z ALONG WITH MODERATE TO HEAVY RAINFALL
SOUTH OF US 20 TO THE IOWA MISSOURI BORDER. THOUGH SOME SEVERE
THREAT EXISTS...THE BIGGER THREAT WILL BE SEVERE WIND GUSTS WHICH
MAY ACCOMPANY THE STORMS THAT ROLL THROUGH THE REGION BETWEEN 21Z
AND 02Z. WITH THE PASSAGE OF THE STORMS AFT 04Z NORTHWEST TO 11Z
SOUTHEAST...CIGS WILL DROP TO IFR/MVFR CATEGORIES WITH POTENTIAL
FOR LIFR CIGS AND VSBY. EXPECTING A RECOVERY TO ONLY MVFR
CONDITIONS BETWEEN 14-18Z MON PRIOR TO NEXT UPSTREAM APPROACHING
WAVE. FOR PLANNING PURPOSES...HEAVY RAINFALL/STORM COVERAGE/POOR
CONDITIONS EXPECTED TO RETURN AGAIN AFT 08/00Z TUES FOR MOST SITES
SOUTH OF US20./REV
&&
.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 FROM 7 PM CDT THIS EVENING 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...REV
HYDROLOGY...REV
AREA FORECAST DISCUSSION
NWS TOPEKA KS
327 PM CDT SUN SEP 6 2015
.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
measoanalysis 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 18Z TAFS THROUGH 18Z Monday AFTERNOON)
ISSUED AT 1237 PM CDT SUN SEP 6 2015
Winds continue to gust through this afternoon from the
south/southwest mainly. Expecting the gusts to calm around 00z
this evening, but brisk winds still remain generally from the
South overnight ahead of the frontal boundary to the North which
will continue progression South but at a slower rate. Confidence
in thunderstorms overnight is not high as indicated by VCTS in the
TAFs. At this point, there isn`t any real strong forcing to help
develop storms until we can get more interaction between the LLJ
and frontal system overnight into the early morning. Expecting
storms to be spotty ahead and along this boundary. At this time,
LLWS isn`t expected to be as strong as it was this morning, so no
mention of that at this time. If winds do calm overnight, this
could change, but certainly not expecting that at this time.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...53
LONG TERM...GDP
AVIATION...Drake
AREA FORECAST DISCUSSION
NWS WICHITA KS
318 PM CDT SUN SEP 6 2015
.SYNOPSIS...
ISSUED AT 318 PM CDT SUN SEP 6 2015
THE UPPER RIDGE IS FLATTENING OUT AS THE UPPER DISTURBANCE MOVES
EASTWARD ACROSS SOUTHERN CANADA/NORTHERN U.S. THE SURFACE TROUGH
IS AHEAD OF THE COLD FRONT...WITH THE TROUGH STRETCHING FROM
LINCOLN, NEBRASKA SOUTHWEST TO RUSSELL, KANSAS AND SOUTH TO DODGE
CITY. THE FRONT IS FURTHER WEST NEARER AURORA, NEBRASKA...SOUTHWEST
TO HILL CITY KANSAS AND SOUTH TO WEST OF GARDEN CITY. TEMPERATURES
AHEAD OF THE FRONT ARE IN THE UPPER 90S AND LOW 100S. OUTSIDE OF
CENTRAL KANSAS...THE DEWPOINTS REMAIN IN THE MID TO UPPER 70S
CAUSING HEAT INDICES TO BE BETWEEN 100 AND 105 ACROSS MUCH OF THE
REGION.
BILLINGS WRIGHT
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 318 PM CDT SUN SEP 6 2015
TONIGHT:
THE CHANCE FOR SCATTERED SHOWERS AND THUNDERSTORMS REMAINS ALONG
AND NEAR THE FRONT IN CENTRAL KANSAS. THE HIGH RESOLUTION GUIDANCE
HAS BEEN CONSISTENT OVER THE PAST FEW RUNS AT DEVELOPING
SCATTERED ACTIVITY ALONG THE FRONT/SURFACE TROUGH AFTER 22Z AND
INTO THE EVENING HOURS. EXPECT MUCH OF THIS ACTIVITY TO BE
DIURNALLY DRIVEN. DURING THE OVERNIGHT HOURS...THE ACTIVITY MAY
MOVE EASTWARD SLIGHTLY...BUT CURRENTLY STRUGGLING TO SEE THE
ACTIVITY IMPACT MUCH MORE THAN CENTRAL KANSAS AND EXTREME WESTERN
PORTIONS OF SOUTH CENTRAL KANSAS. MOISTURE TRANSPORT DOES INCREASE
OVERNIGHT ACROSS SOUTHERN KANSAS...THUS CANNOT RULE OUT
PRECIPITATION TOWARD MORNING.
MONDAY - WEDNESDAY:
THE FRONTAL PLACEMENT WILL RULE THE FIRST PART OF THE WORK WEEK.
THE LATEST GUIDANCE REINFORCES PREVIOUS RUNS SHOWING THE FRONT
STALLING OUT ACROSS CENTRAL KANSAS. BECAUSE OF THE STALLING OF THE
FRONT...CENTRAL KANSAS WILL HAVE THE BEST CHANCES FOR
PRECIPITATION MONDAY AND MONDAY NIGHT. BECAUSE MUCH OF SOUTHEAST
KANSAS WILL BE IN THE WARM SECTOR...TEMPERATURES WILL AGAIN BE
HOT WITH HEAT INDICES AGAIN BETWEEN 100 AND 105 ACROSS MUCH OF
AREA MONDAY AFTERNOON. TEMPERATURES WILL AGAIN BE IN THE MID TO
UPPER 90S.
BY TUESDAY THE UPPER LOW LEVEL DISTURBANCE WILL APPROACH FROM THE
NORTHWEST WHICH WILL PUSH THE FRONT FURTHER SOUTHEAST. SCATTERED
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO BE MORE WIDESPREAD
TUESDAY WITH THE UPPER DISTURBANCE NEARER TO PROVIDE SYNOPTIC
SUPPORT. TEMPERATURES ARE EXPECTED TO BE SLIGHTLY COOLER WITH THE
PRECIPITATION CHANCES AND CLOUDS AS WELL AS THE FRONT FINALLY
PUSHING SOUTHWARD. CURRENT GUIDANCE INDICATES THAT THE FRONT WILL
MOVE OUT OF THE REGION BY LATE TUESDAY NIGHT/EARLY WEDNESDAY.
EXPECT WEDNESDAY TO BE DRY AS THE FRONT WILL HAVE EXITED THE
AREA...WITH TEMPERATURES IN THE 80S.
BILLINGS WRIGHT
.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 318 PM CDT SUN SEP 6 2015
THE SECOND HALF OF THE WORK WEEK IS EXPECTED TO BE COOLER WITH A
SECONDARY PUSH OF COOLER AIR MOVING THROUGH FRIDAY. PRECIPITATION
CHANCES REMAIN SCATTERED ACROSS THE AREA THROUGH THE PERIOD...AS
THE CENTRAL PLAINS WILL TRANSITION TO A NORTHWESTERLY FLOW REGIME.
DIFFERENT DISTURBANCES WILL MOVE SOUTHWARD INTO THE TROUGH OVER
THE EAST WHICH WILL INCREASE THE CHANCES FOR PRECIPITATION.
SIMILAR TO YESTERDAY...DO NOT EXPECT THE WHOLE PERIOD TO BE
RAINY...BUT CHANCES DO PERSIST. DUE TO THE COOL
FRONTS...PRECIPITATION AND THE RIDGE TRANSITIONING
WESTWARD...HIGHS FOR THIS PERIOD LOOK TO BE IN THE 70S AND LOW
80S.
BILLINGS WRIGHT
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1235 PM CDT SUN SEP 6 2015
MAIN AVIATION CONCERN WILL BE CONVECTIVE CHANCES ASSOCIATED WITH A
COLD FRONT.
COLD FRONT CURRENTLY STRETCHES FROM EASTERN NEBRASKA INTO NW KS.
THERE LOOKS TO BE A PRE-FRONTAL TROUGH OUT AHEAD OF THE FRONT THAT
HAS CREPT INTO SOUTH CENTRAL NEBRASKA/NORTH CENTRAL KS. THE MAIN
QUESTION WILL BE IF CONVECTION CAN DEVELOP ALONG THIS PRE-FRONTAL
CONVERGENCE AREA LATE THIS AFTERNOON/EARLY EVENING. THE RUC13 HAS
BEEN CONSISTENT IN GENERATING PRECIP ALONG OR JUST AHEAD OF THIS
FEATURE IN AN AREA OF EXTREME HEATING. FOR NOW WILL GO AHEAD AND
MENTION VCTS AT KRSL WITH LOW CONFIDENCE IN DEVELOPMENT. FAIRLY
CONFIDENT THAT IF STORMS DEVELOP THEY WILL BE FAIRLY ISOLATED.
LAWSON
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 74 96 76 90 / 10 20 20 50
HUTCHINSON 74 98 76 89 / 30 30 30 40
NEWTON 74 94 75 87 / 20 20 30 50
ELDORADO 74 95 76 89 / 20 20 20 60
WINFIELD-KWLD 75 95 76 91 / 10 10 10 50
RUSSELL 69 94 70 86 / 40 40 40 40
GREAT BEND 70 96 72 87 / 50 40 40 40
SALINA 73 95 75 87 / 50 30 50 50
MCPHERSON 73 96 74 87 / 40 30 30 50
COFFEYVILLE 74 95 75 90 / 10 10 10 50
CHANUTE 74 93 75 88 / 10 10 20 60
IOLA 74 92 75 88 / 10 10 20 60
PARSONS-KPPF 75 93 76 89 / 10 10 10 50
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
1243 PM CDT SUN SEP 6 2015
...UPDATED FOR 18Z AVIATION DISCUSSION...
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 228 AM CDT SUN SEP 6 2015
HIGHLY AMPLIFIED MERIDIONAL FLOW PATTERN WAS NOTED ON
WATER VAPOR IMAGERY THIS MORNING ACROSS THE UNITED STATES. THE LOW
THAT IS OVER THE PACIFIC NORTHWEST IS OPENING UP AND MOVING
EAST...WHICH HAS BEEN ANTICIPATED FOR SEVERAL DAYS. THE DOWNSTREAM
RIDGE...WHICH IS WAS CENTERED RIGHT ACROSS THE FORECAST AREA THIS
MORNING...WILL CONTINUE TO PRODUCE ABOVE NORMAL TEMPERATURES ACROSS
THE EASTERN HALF OF THE NATION.
MAIN SHORT TERM FORECAST CHALLENGE REMAINS TEMPERATURES. CONFIDENCE
REMAINS HIGH THAT TEMPERATURES WILL BE AT LEAST 5 DEGREES ABOVE
NORMAL THROUGH MONDAY. THERE IS FAIRLY GOOD AGREEMENT WITH THE NWP
MODELS ON THE TIMING OF THE PRECIPITATION AND FRONT MOVING INTO THE
REGION.
THERE WERE SOME SCATTERED AIR MASS THUNDERSTORMS AROUND THE REGION
LAST EVENING...BUT NOT ACROSS THE FORECAST AREA. WITH THE INCREASE
IN DEWPOINTS ACROSS THE REGION TODAY...THERE COULD BE ISOLATED
THUNDERSTORMS AROUND...BUT PREDICTABILITY IS SO LOW WILL NOT INCLUDE
THAT IN THE FORECAST. LOOKING AT MAYBE A 5 PERCENT CHANCE OR SO.
TODAY AND MONDAY WILL BE THE HOTTEST DAYS...MAINLY THE RESULT OF
HIGHER DEWPOINTS AND COMPRESSIONAL WARMING WITH THE FRONT MOVING
INTO THE REGION. THE INCREASE IN DEWPOINTS WILL ALSO CAUSE THE HEAT
INDICES TO PUSH CLOSER TOWARD ADVISORY CRITERIA /105 DEGREES/.
THE FRONT WILL NEAR THE FORECAST AREA MONDAY...BUT REMAIN NORTHWEST.
THUNDERSTORMS WILL DEVELOP ALONG THE FRONT...BUT THE MEAN STORM
MOTION SHOULD KEEP THE BULK OF THEM NORTHWEST OF THE FORECAST AREA.
CHANCE OF THUNDERSTORMS WARRANTED FOR CENTRAL KANSAS.
THE FRONT MOVES INTO THE FORECAST AREA TUESDAY. THIS IS WHEN
THUNDERSTORMS ACROSS THE FORECAST AREA REALLY GET GOING IN EARNEST.
AS HAS BEEN THE CASE...SHEAR/BUOYANCY COMBINATIONS STILL SUGGEST AN
UNFAVORABLE ENVIRONMENT FOR ORGANIZED SEVERE WEATHER.
KRC
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 228 AM CDT SUN SEP 6 2015
HIGH PRESSURE WILL MOVE INTO THE UPPER MISSISSIPPI RIVER VALLEY.
ISENTROPIC LIFT WITH THE RETURN FLOW DOES CONTINUE SHOWER AND
THUNDERSTORM CHANCES THROUGH MUCH OF THE PERIOD. TEMPERATURES
WILL BE WELL BELOW NORMAL DURING THIS TIME.
KRC
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1235 PM CDT SUN SEP 6 2015
MAIN AVIATION CONCERN WILL BE CONVECTIVE CHANCES ASSOCIATED WITH A
COLD FRONT.
COLD FRONT CURRENTLY STRETCHES FROM EASTERN NEBRASKA INTO NW KS.
THERE LOOKS TO BE A PRE-FRONTAL TROUGH OUT AHEAD OF THE FRONT THAT
HAS CREPT INTO SOUTH CENTRAL NEBRASKA/NORTH CENTRAL KS. THE MAIN
QUESTION WILL BE IF CONVECTION CAN DEVELOP ALONG THIS PRE-FRONTAL
CONVERGENCE AREA LATE THIS AFTERNOON/EARLY EVENING. THE RUC13 HAS
BEEN CONSISTENT IN GENERATING PRECIP ALONG OR JUST AHEAD OF THIS
FEATURE IN AN AREA OF EXTREME HEATING. FOR NOW WILL GO AHEAD AND
MENTION VCTS AT KRSL WITH LOW CONFIDENCE IN DEVELOPMENT. FAIRLY
CONFIDENT THAT IF STORMS DEVELOP THEY WILL BE FAIRLY ISOLATED.
LAWSON
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 97 74 96 74 / 0 20 30 30
HUTCHINSON 97 74 95 73 / 10 30 40 40
NEWTON 97 73 94 72 / 10 30 30 40
ELDORADO 97 74 94 74 / 0 20 30 30
WINFIELD-KWLD 97 75 95 75 / 0 10 20 20
RUSSELL 100 69 92 69 / 20 30 40 40
GREAT BEND 100 71 95 70 / 20 30 40 30
SALINA 99 73 94 73 / 20 40 40 50
MCPHERSON 97 73 94 72 / 10 30 40 40
COFFEYVILLE 93 74 93 74 / 0 10 20 20
CHANUTE 92 74 92 74 / 0 10 30 40
IOLA 92 75 91 74 / 0 20 30 40
PARSONS-KPPF 92 74 93 75 / 0 10 20 30
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS JACKSON KY
551 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 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 124 PM EDT SUN SEP 6 2015
VFR CONDITIONS AND PARTLY CLOUDY SKIES WILL PREVAIL AT THE TAF
SITES THROUGH AROUND 5Z TONIGHT. ONCE THE CLOUDS CLEAR OFF A BIT
LATE TONIGHT...AND WINDS GO CALM AGAIN...VALLEY FOG IS EXPECTED TO
FROM ACROSS THE AREA. MVFR FOG IS FORECAST TO AFFECT ALL OF THE
TAF SITES EXCEPT JKL. THE FOG WILL BEGIN TO LIFT AND DISSIPATE
WHILE THE SUN IS COMING UP ON MONDAY MORNING...AND SHOULD BE GONE
BY 13Z. WINDS THROUGH OUT THE PERIOD SHOULD BE LIGHT AND VARIABLE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JMW
SHORT TERM...AR
LONG TERM...GEOGERIAN
AVIATION...AR
AREA FORECAST DISCUSSION
NWS JACKSON KY
405 PM EDT SUN SEP 6 2015
.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 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 124 PM EDT SUN SEP 6 2015
VFR CONDITIONS AND PARTLY CLOUDY SKIES WILL PREVAIL AT THE TAF
SITES THROUGH AROUND 5Z TONIGHT. ONCE THE CLOUDS CLEAR OFF A BIT
LATE TONIGHT...AND WINDS GO CALM AGAIN...VALLEY FOG IS EXPECTED TO
FROM ACROSS THE AREA. MVFR FOG IS FORECAST TO AFFECT ALL OF THE
TAF SITES EXCEPT JKL. THE FOG WILL BEGIN TO LIFT AND DISSIPATE
WHILE THE SUN IS COMING UP ON MONDAY MORNING...AND SHOULD BE GONE
BY 13Z. WINDS THROUGH OUT THE PERIOD SHOULD BE LIGHT AND VARIABLE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...AR
LONG TERM...GEOGERIAN
AVIATION...AR
AREA FORECAST DISCUSSION
NWS JACKSON KY
301 PM EDT SUN SEP 6 2015
.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 300 PM EDT SUN SEP 6 2015
AN EXTENDED DISCUSSION WILL BE ISSUED SHORTLY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 124 PM EDT SUN SEP 6 2015
VFR CONDITIONS AND PARTLY CLOUDY SKIES WILL PREVAIL AT THE TAF
SITES THROUGH AROUND 5Z TONIGHT. ONCE THE CLOUDS CLEAR OFF A BIT
LATE TONIGHT...AND WINDS GO CALM AGAIN...VALLEY FOG IS EXPECTED TO
FROM ACROSS THE AREA. MVFR FOG IS FORECAST TO AFFECT ALL OF THE
TAF SITES EXCEPT JKL. THE FOG WILL BEGIN TO LIFT AND DISSIPATE
WHILE THE SUN IS COMING UP ON MONDAY MORNING...AND SHOULD BE GONE
BY 13Z. WINDS THROUGH OUT THE PERIOD SHOULD BE LIGHT AND VARIABLE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...AR
LONG TERM...GEOGERIAN
AVIATION...AR
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
432 PM EDT SUN SEP 6 2015
.SYNOPSIS...
HIGH PRESSURE WILL BECOME NEARLY STATIONARY OFF THE MID ATLANTIC
TONIGHT THROUGH WEDNESDAY. A COLD FRONT ENTERS THE LOCAL AREA
WEDNESDAY NIGHT THROUGH THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
SFC HI PRES RMNS SITUATED SE OF NEW ENG THIS AFTN...WHILE ALOFT...AN
UPPER LOW IS FOUND OVER THE SERN STATES. THE UPPER LOW WILL SLOWLY
RETROGRADE TO THE NRN GULF OF MEX THROUGH TNGT...WHILE THE SFC HI
SETTLE S TO OFF THE MDATLC CST. WNDS BECOME LGT/VRB INLAND...RMNG
MNLY NE...KEEPING SOMEWHAT UNSETTLED OVER MUCH OF SRN/SE VA...NE
NC AND THE LWR ERN SHORE. PLUME OF MOISTURE CONTS TO SPREAD NNW
THROUGH ERN NC INTO SRN/SE VA THIS AFTN. NR TERM MDL GUID HAVING
DIFFICULTY W/ COVERAGE OF CLDS/PCPN ATTM...THOUGH SUGGEST THAT THE
AREA OF MOISTURE SLOLY PUSHES WWD/INLAND WHILE SLOLY DISSIPATING
OVRNGT. WILL KEEP 20-40% POPS ACROSS SRN/SE PORTIONS OF THE
FA THROUGH ABT 02-04Z/07 (PRIMARILY SHRAS N OF THE VA/NC
BORDER...WILL INCLUDE ISOLD TSTMS IN NE NC). KEEPING POPS AOB 15%
N OF A LINE FM FVX-RIC-MFV. AFT MDNGT...WILL HAVE POPS AOB 15% ALL
AREAS. SKY CLR-PARTLY CLOUDY N...VRB CLDS-MOSTLY CLOUDY CNTRL/S.
LO TEMPS FM THE M60S-ARND 70F.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
A RETURN OF SUMMERY WX FOR MON-WED ACRS THE FA. A GRADUAL EROSION
OF THE ONSHORE FLO IS XPCD MON AS THE SFC HI PRES SETS UP OFF THE
MDATLC CST. THIS LEADS TO A BETTER PROB FOR MORE SUNSHINE ALL
AREAS ALONG WITH WARMER TEMPS...THOUGH WILL KEEP WITH 15-20% POPS
ACRS PORTIONS OF NE NC. HI TEMPS 85-90F INLAND...80-85F AT THE
BEACHES.
HI PRES RMNS JUST OFF THE CST TUE/WED W/ MNLY SLY FLO OF MODERATE
DEWPOINTS AND ONLY LIMITED CHCS FOR (DIURNAL) SHWRS/TSTMS. WILL
MAINTAIN SLIGHT CHC POPS OVR CSTL NE NC ON TUE...THEN HAVE POPS
AVGG 30% BY WED AFTN AS DEEPER LYRD MOISTURE ARRIVES AHEAD OF
CDFNT CROSSING THE OH VLY. HI TEMPS BOTH TUE/WED FM THE M80S AT
THE COAST...TO L90S INLAND. LO TEMPS FM THE U60S TO L70S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
UPPER FLOW AMPLIFIES THRU THE EXTENDED PERIOD AS AN ANOMALOUS
TROUGH DEVELOPS OVER THE EASTERN HALF OF THE COUNTRY...UPSTREAM OF
RIDGING OVER THE WESTERN ATLANTIC. ASSOCIATED COLD FRONT REACHES THE
LOCAL AREA WEDS NIGHT INTO THURS...STALLING OVER THE MID-ATLANTIC
REGION THURS IN SWLY FLOW ALOFT. DEEP LAYER SWLY FLOW WILL RESULT IN
GOOD MOISTURE RETURN IN ADVANCE OF THE FRONT. THE RESULT WILL BE
INCREASING CHANCES FOR PRECIP BEGINNING WEDS NIGHT...AND CONTINUING
INTO NEXT WEEKEND AS THE FRONT REMAINS STALLED OVER THE REGION. DUE
TO THE STRENGTH OF THE RIDGE OVER THE WRN ATLANTIC...THE GFS LIKELY
PUSHES THE FRONT OFFSHORE TOO QUICKLY NEXT WEEKEND. THIS WOULD FAVOR
A QUICKER END TO THE PRECIP AND COOLER TEMPS COMPARED TO ITS ECMWF
AND ENSEMBLE COUNTERPARTS. HAVE TRENDED POPS AND TEMPS TOWARD THE
ECMWF AS A RESULT. THIS YIELDS A COOLING TREND THRU THE
PERIOD...WITH HIGHS FORECAST IN THE UPPER 70S TO LOW 80S SAT AND
SUN AS H85 TEMPS DROP DOWN AROUND 10 TO 12C.
&&
.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
A MOIST NE/E FLOW CONTINUES WITH HIGH PRESSURE ANCHORED OVER
NORTHERN PORTIONS OF THE MID ATLANTIC STATES. WATER VAPOR IMAGERY
CLEARLY SHOWS A CLOSED UPPER LOW OVER THE SOUTHERN APPALACHIANS WITH
MOISTURE STREAMING NORTHWARD INTO EASTERN VIRGINIA. RAIN IS MORE
WIDESPREAD ACROSS SE VA AND NE NC THAN 24 HOURS AGO. HRRR INDICATES
PCPN DIMINISHING BY LATE AFTN AND THE TAFS ARE BASED ON THIS
EXPECTATION. NAM BUFR SOUNDINGS DO NOT SUPPORT MUCH STRATUS
OVERNIGHT. INCLUDED SOME FOG ESPECIALLY AT PHF.
ON MONDAY...HIGH PRESSURE SETTLES FARTHER TO THE SOUTH AND A DRY DAY
IS EXPECTED WITH ONLY SCT CU.
OUTLOOK...HIGH PRESSURE WILL SLOWLY SLIDE OFF THE COAST THROUGH
MIDWEEK. LITTLE OR NO PCPN IS FORECAST THROUGH WEDNESDAY WITH A CHC
FOR MAINLY AFTN TSTMS THURSDAY AND FRIDAY. MAINLY VFR CONDITIONS ARE
EXPECTED WITH A FEW HOURS OF MVFR PSBL AROUND SUNRISE. A COLD
FRONT APPROACHES THE AREA BY THE END OF THE WEEK.
&&
.MARINE...
HIGH PRESSURE HAS CENTERED OFF THE DELMARVA COAST THIS
AFTERNOON...RIDGING SWWD OVER THE LOCAL WATERS. THE RESULT IS
ONGOING NE FLOW OF 10 TO 20 KT. SCA CONDS CONTINUE IN THE COASTAL
WATERS SOUTH OF CAPE CHARLES LIGHT (4-5 FT SEAS) AND IN THE MOUTH OF
THE BAY (GUSTS TO 20 KT AND 4 FT WAVES) THROUGH 7PM. HI-RES GUIDANCE
DROPS SPEEDS BELOW 15 KT BY 7PM ALL WATERS AS THE HIGH BUILDS SWD.
OTHERWISE...HIGH PRESSURE WILL GRADUALLY SLIDE OFF THE COAST MONDAY
THROUGH THURSDAY. E/SE FLOW AOB 15KT IS EXPECTED
MONDAY/TUESDAY...BEFORE THE WIND SHIFTS TO SSW AOB 15KT BY
WEDNESDAY/THURSDAY AS THE HIGH SLIDES FARTHER OFFSHORE. SEAS SHOULD
AVERAGE 2-3FT DURING THIS TIMEFRAME WITH 1-2FT WAVES. A COLD FRONT
DROPS INTO THE REGION THURS...STALLING NEAR THE WATER INTO NEXT
WEEKEND.
WHILE NEARSHORE WAVES OF 2-3 FT ARE FORECAST MON...SHORE NORMAL WAVE
DIRECTIONS...PERSISTENT ONSHORE FLOW AND LONG PERIOD SWELL WILL
ENHANCE THE THREAT OF RIP CURRENTS.
&&
.TIDES/COASTAL FLOODING...
TIDAL ANOMALIES HAVE DROPPED AOB 1 FT ABOVE NORMAL THIS AFTERNOON.
NO TIDAL FLOODING IS EXPECTED AT THIS TIME. HOWEVER...BISHOPS
HEAD AND LEWISETTA WILL BE CLOSE TO MINOR THRESHOLDS DURING HIGH
TIDE THIS EVENING.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR ANZ634-
656-658.
&&
$$
SYNOPSIS...ALB/JDM
NEAR TERM...ALB/JDM
SHORT TERM...ALB/JDM
LONG TERM...SAM
AVIATION...LSA
MARINE...AJZ/SAM
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
300 PM EDT SUN SEP 6 2015
.SYNOPSIS...
HIGH PRESSURE WILL BECOME NEARLY STATIONARY OFF THE MID ATLANTIC
TONIGHT THROUGH WEDNESDAY. A COLD FRONT ENTERS THE LOCAL AREA
WEDNESDAY NIGHT THROUGH THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
SFC HI PRES RMNS SITUATED SE OF NEW ENG THIS AFTN...WHILE ALOFT...AN
UPPER LOW IS FOUND OVER THE SERN STATES. THE UPPER LOW WILL SLOWLY
RETROGRADE TO THE NRN GULF OF MEX THROUGH TNGT...WHILE THE SFC HI
SETTLE S TO OFF THE MDATLC CST. WNDS BECOME LGT/VRB INLAND...RMNG
MNLY NE...KEEPING SOMEWHAT UNSETTLED OVER MUCH OF SRN/SE VA...NE
NC AND THE LWR ERN SHORE. PLUME OF MOISTURE CONTS TO SPREAD NNW
THROUGH ERN NC INTO SRN/SE VA THIS AFTN. NR TERM MDL GUID HAVING
DIFFICULTY W/ COVERAGE OF CLDS/PCPN ATTM...THOUGH SUGGEST THAT THE
AREA OF MOISTURE SLOLY PUSHES WWD/INLAND WHILE SLOLY DISSIPATING
OVRNGT. WILL KEEP 20-40% POPS ACROSS SRN/SE PORTIONS OF THE
FA THROUGH ABT 02-04Z/07 (PRIMARILY SHRAS N OF THE VA/NC
BORDER...WILL INCLUDE ISOLD TSTMS IN NE NC). KEEPING POPS AOB 15%
N OF A LINE FM FVX-RIC-MFV. AFT MDNGT...WILL HAVE POPS AOB 15% ALL
AREAS. SKY CLR-PARTLY CLOUDY N...VRB CLDS-MOSTLY CLOUDY CNTRL/S.
LO TEMPS FM THE M60S-ARND 70F.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
A RETURN OF SUMMERY WX FOR MON-WED ACRS THE FA. A GRADUAL EROSION
OF THE ONSHORE FLO IS XPCD MON AS THE SFC HI PRES SETS UP OFF THE
MDATLC CST. THIS LEADS TO A BETTER PROB FOR MORE SUNSHINE ALL
AREAS ALONG WITH WARMER TEMPS...THOUGH WILL KEEP WITH 15-20% POPS
ACRS PORTIONS OF NE NC. HI TEMPS 85-90F INLAND...80-85F AT THE
BEACHES.
HI PRES RMNS JUST OFF THE CST TUE/WED W/ MNLY SLY FLO OF MODERATE
DEWPOINTS AND ONLY LIMITED CHCS FOR (DIURNAL) SHWRS/TSTMS. WILL
MAINTAIN SLIGHT CHC POPS OVR CSTL NE NC ON TUE...THEN HAVE POPS
AVGG 30% BY WED AFTN AS DEEPER LYRD MOISTURE ARRIVES AHEAD OF
CDFNT CROSSING THE OH VLY. HI TEMPS BOTH TUE/WED FM THE M80S AT
THE COAST...TO L90S INLAND. LO TEMPS FM THE U60S TO L70S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
DURING THE LAST HALF OF THE WEEK...RIDGING OVER THE SOUTHEAST STATES
WILL GRADUALLY YIELD TO LOWERING HEIGHTS OVER THE ERN CONUS. THIS
WILL BRING INCREASING CHANCES FOR PCPN. UPPER LEVEL TROUGHING WILL
APPROACH FROM THE WEST AND A COLD FRONT MAY CROSS THE MID ATLANTI8C
STATES AROUND SATURDAY. GFS IS QUICKER WITH THIS FRONT AND THE EURO
IS SLOWER BUT LOWER WITH UPPER LEVEL HEIGHTS. THE FORECAST WEIGHS
HEAVILY ON SUPER BLEND BUT ALSO INCLUDES PARTS OF THE PREVIOUS
FORECAST AND HPC GUIDANCE. POPS FOR SHOWERS AND MAINLY AFTN TSTMS
ARE GENERALLY IN THE CHC CATEGORY FROM THURSDAY THROUGH SATURDAY
WITH 40 PERCENT CHANCES FRIDAY AND SATURDAY. DETAILS FOR SATURDAY
WILL BE AFFECTED BY THE TIMING OF THE COLD FRONT IF IT ARRIVES THEN.
HIGH TEMPERATURES OF 85 TO 90 WILL BE A BIT COOLER NEAR THE SHORE.
HAVE SLIGHTLY LOWER READINGS SATURDAY FAR WESTERN PORTIONS LOWS
RANGE FROM THE UPR 60S TO LWR 70S.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
A MOIST NE/E FLOW CONTINUES WITH HIGH PRESSURE ANCHORED OVER
NORTHERN PORTIONS OF THE MID ATLANTIC STATES. WATER VAPOR IMAGERY
CLEARLY SHOWS A CLOSED UPPER LOW OVER THE SOUTHERN APPALACHIANS WITH
MOISTURE STREAMING NORTHWARD INTO EASTERN VIRGINIA. RAIN IS MORE
WIDESPREAD ACROSS SE VA AND NE NC THAN 24 HOURS AGO. HRRR INDICATES
PCPN DIMINISHING BY LATE AFTN AND THE TAFS ARE BASED ON THIS
EXPECTATION. NAM BUFR SOUNDINGS DO NOT SUPPORT MUCH STRATUS
OVERNIGHT. INCLUDED SOME FOG ESPECIALLY AT PHF.
ON MONDAY...HIGH PRESSURE SETTLES FARTHER TO THE SOUTH AND A DRY DAY
IS EXPECTED WITH ONLY SCT CU.
OUTLOOK...HIGH PRESSURE WILL SLOWLY SLIDE OFF THE COAST THROUGH
MIDWEEK. LITTLE OR NO PCPN IS FORECAST THROUGH WEDNESDAY WITH A CHC
FOR MAINLY AFTN TSTMS THURSDAY AND FRIDAY. MAINLY VFR CONDITIONS ARE
EXPECTED WITH A FEW HOURS OF MVFR PSBL AROUND SUNRISE. A COLD
FRONT APPROACHES THE AREA BY THE END OF THE WEEK.
&&
.MARINE...
ADJUSTMENTS WERE MADE WITH THE SCA HEADLINES. EXTENDED THE SCA FOR
THE MOUTH OF THE BAY AS HI RES MODELS INDICATE NE WINDS WILL
INCREASE FOR A FEW HOURS AROUND MIDDAY. THE SCA OVER THE COASTAL
WATERS NORTH OF PARRAMORE ISLAND WAS CANCELLED AS WINDS AND SEAS
HAVE DIMINISHED IN THAT AREA.
PREVIOUS DISCUSSION...
HIGH PRESSURE OVER THE NORTHEAST WILL GRADUALLY BUILD SWD INTO
THE MID-ATLANTIC TODAY AS A TROUGH WEAKENS OFF THE VA/NC COAST.
THEREFORE...THE PERSISTENT NE WIND WILL GRADUALLY DIMINISH TODAY
AS THE PRESSURE GRADIENT SLACKENS. A 15-20KT WIND STILL PERSISTS
ACROSS THE LOWER BAY ALONG WITH 3-4FT WAVES IN THE MOUTH OF THE
BAY. THE SCA S OF NEW POINT COMFORT WILL RUN THROUGH 7AM TO
ACCOUNT FOR THE WIND...WHILE THE SCA FOR THE MOUTH OF THE BAY WILL
RUN UNTIL 10AM TO ACCOUNT FOR THE POTENTIAL OF 4FT WAVES. SCAS FOR
THE OCEAN WILL END FROM N-S THIS AFTERNOON AS SEAS GRADUALLY
SUBSIDE FROM 4-5FT N/5-6FT S...TO 3-4FT N/4-5FT S.
OTHERWISE...HIGH PRESSURE WILL GRADUALLY SLIDE OFF THE COAST
MONDAY THROUGH THURSDAY. E/SE FLOW AOB 15KT IS EXPECTED
MONDAY/TUESDAY...BEFORE THE WIND SHIFTS TO SSW AOB 15KT BY
WEDNESDAY/THURSDAY AS THE HIGH SLIDES FARTHER OFFSHORE. SEAS
SHOULD AVERAGE 2-3FT DURING THIS TIMEFRAME WITH 1-2FT WAVES.
PERSISTENT ONSHORE FLOW AND HIGH NEARSHORE WAVES WILL ENHANCE THE
THREAT OF RIP CURRENTS TODAY AND POTENTIALLY INTO MONDAY.
&&
.TIDES/COASTAL FLOODING...
TIDAL ANOMALIES WILL GRADUALLY DROP FROM 1.0-1.5 FT ABOVE NORMAL
TO BELOW 1.0 FT ABOVE NORMAL TODAY AS A NE WIND RELAXES. NO TIDAL
FLOODING IS EXPECTED AT THIS TIME. HOWEVER...BISHOPS HEAD AND
LEWISETTA WILL BE CLOSE TO MINOR THRESHOLDS DURING HIGH TIDE THIS
MORNING AND EARLY THIS EVENING.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EDT THIS AFTERNOON FOR ANZ634.
SMALL CRAFT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR ANZ656-
658.
&&
$$
SYNOPSIS...ALB/JDM
NEAR TERM...ALB/JDM
SHORT TERM...ALB/JDM
LONG TERM...LSA
AVIATION...LSA
MARINE...AJZ/LSA
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
217 PM EDT SUN SEP 6 2015
.SYNOPSIS...
HIGH PRESSURE WILL BUILD FROM SOUTHERN NEW ENGLAND SOUTH TO OFF
THE MID ATLANTIC COAST THROUGH MONDAY. HIGH PRESSURE THEN REMAINS
IN CONTROL THROUGH MIDWEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SFC HI PRES IS SITUATED SE OF NEW ENG LATE THIS MRNG.
MEANWHILE...ALOFT...AN UPPER LOW IS FOUND OVER THE SERN STATES.
THE UPPER LOW WILL SLOWLY RETROGRADE TO THE NORTHERN GOMEX THROUGH
THIS EVE. AT THE SAME TIME...THE SFC HI TO THE NE WILL BEGIN TO
NUDGE S. WNDS RMN NE...KEEPING SOMEWHAT UNSETTLED OVER MUCH OF
SRN/SE VA...NE NC AND THE LWR ERN SHORE. WATCHING ISOLD/SCT SHRAS
SPREADING WNW THROUGH SE VA/NE NC...AND XPCD TO CONT TO DO SO THIS
AFTN. WILL KEEP 30-40% POPS ACROSS SRN/SE PORTIONS OF THE FA...W/SLIGHT
CHC POPS (15-20%) AS FAR N AS A LINE FROM FVX-RIC-MFV. BY LATE
THIS AFTN/EVE...BEST CHC FOR PCPN SHOULD BE LIMITED TO FAR
SOUTHERN VA AND NE NC. DRY ACROSS THE N THIS AFTN W/ SKY AVGG
PARTLY SUNNY. VRB CLDS-MOSTLY CLOUDY CNTRL/S. HI TEMPS MNLY 80 TO
85F.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
DRY OVERNIGHT TONIGHT. MAINLY CLEAR NORTH TO PTLY TO MSTLY CLOUDY
SOUTH. LOWS MOSTLY IN THE 60S.
BY MONDAY...GRADUAL EROSION OF THE ONSHORE FLOW IS EXPECTED AS THE
SFC HIGH BEGINS TO NUDGE OFF THE MID-ATLANTIC COAST. THIS LEADS TO
A BETTER PROBABILITY FOR MORE SUNSHINE ALL AREAS ALONG WITH WARMER
TEMPS...THOUGH WILL KEEP WITH 15-25% POPS IN FAR SE VA AND NE NC.
HIGH TEMPS IN THE MID/UPR 80S...EXCEPT LOW 80S COAST.
HIGH PRESSURE NEAR OR JUST OFF THE COAST ON TUE (SERLY FLOW) WILL
LEAD TO A RETURN OF SUMMERY CONDITIONS AND LIMITED CHCS FOR
(DIURNAL) SHWRS/TSTMS. WILL MAINTAIN SLIGHT CHC POPS OVER NE NC.
HIGH TEMPS FROM THE MID 80S AT THE COAST...TO LOW 90S WELL INLAND.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
DURING THE LAST HALF OF THE WEEK...RIDGING OVER THE SOUTHEAST STATES
WILL GRADUALLY YIELD TO LOWERING HEIGHTS OVER THE ERN CONUS. THIS
WILL BRING INCREASING CHANCES FOR PCPN. UPPER LEVEL TROUGHING WILL
APPROACH FROM THE WEST AND A COLD FRONT MAY CROSS THE MID ATLANTI8C
STATES AROUND SATURDAY. GFS IS QUICKER WITH THIS FRONT AND THE EURO
IS SLOWER BUT LOWER WITH UPPER LEVEL HEIGHTS. THE FORECAST WEIGHS
HEAVILY ON SUPER BLEND BUT ALSO INCLUDES PARTS OF THE PREVIOUS
FORECAST AND HPC GUIDANCE. POPS FOR SHOWERS AND MAINLY AFTN TSTMS
ARE GENERALLY IN THE CHC CATEGORY FROM THURSDAY THROUGH SATURDAY
WITH 40 PERCENT CHANCES FRIDAY AND SATURDAY. DETAILS FOR SATURDAY
WILL BE AFFECTED BY THE TIMING OF THE COLD FRONT IF IT ARRIVES THEN.
HIGH TEMPERATURES OF 85 TO 90 WILL BE A BIT COOLER NEAR THE SHORE.
HAVE SLIGHTLY LOWER READINGS SATURDAY FAR WESTERN PORTIONS LOWS
RANGE FROM THE UPR 60S TO LWR 70S.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
A MOIST NE/E FLOW CONTINUES WITH HIGH PRESSURE ANCHORED OVER
NORTHERN PORTIONS OF THE MID ATLANTIC STATES. WATER VAPOR IMAGERY
CLEARLY SHOWS A CLOSED UPPER LOW OVER THE SOUTHERN APPALACHIANS WITH
MOISTURE STREAMING NORTHWARD INTO EASTERN VIRGINIA. RAIN IS MORE
WIDESPREAD ACROSS SE VA AND NE NC THAN 24 HOURS AGO. HRRR INDICATES
PCPN DIMINISHING BY LATE AFTN AND THE TAFS ARE BASED ON THIS
EXPECTATION. NAM BUFR SOUNDINGS DO NOT SUPPORT MUCH STRATUS
OVERNIGHT. INCLUDED SOME FOG ESPECIALLY AT PHF.
ON MONDAY...HIGH PRESSURE SETTLES FARTHER TO THE SOUTH AND A DRY DAY
IS EXPECTED WITH ONLY SCT CU.
OUTLOOK...HIGH PRESSURE WILL SLOWLY SLIDE OFF THE COAST THROUGH
MIDWEEK. LITTLE OR NO PCPN IS FORECAST THROUGH WEDNESDAY WITH A CHC
FOR MAINLY AFTN TSTMS THURSDAY AND FRIDAY. MAINLY VFR CONDITIONS ARE
EXPECTED WITH A FEW HOURS OF MVFR PSBL AROUND SUNRISE. A COLD
FRONT APPROACHES THE AREA BY THE END OF THE WEEK.
&&
.MARINE...
ADJUSTMENTS WERE MADE WITH THE SCA HEADLINES. EXTENDED THE SCA FOR
THE MOUTH OF THE BAY AS HI RES MODELS INDICATE NE WINDS WILL
INCREASE FOR A FEW HOURS AROUND MIDDAY. THE SCA OVER THE COASTAL
WATERS NORTH OF PARRAMORE ISLAND WAS CANCELLED AS WINDS AND SEAS
HAVE DIMINISHED IN THAT AREA.
PREVIOUS DISCUSSION...
HIGH PRESSURE OVER THE NORTHEAST WILL GRADUALLY BUILD SWD INTO
THE MID-ATLANTIC TODAY AS A TROUGH WEAKENS OFF THE VA/NC COAST.
THEREFORE...THE PERSISTENT NE WIND WILL GRADUALLY DIMINISH TODAY
AS THE PRESSURE GRADIENT SLACKENS. A 15-20KT WIND STILL PERSISTS
ACROSS THE LOWER BAY ALONG WITH 3-4FT WAVES IN THE MOUTH OF THE
BAY. THE SCA S OF NEW POINT COMFORT WILL RUN THROUGH 7AM TO
ACCOUNT FOR THE WIND...WHILE THE SCA FOR THE MOUTH OF THE BAY WILL
RUN UNTIL 10AM TO ACCOUNT FOR THE POTENTIAL OF 4FT WAVES. SCAS FOR
THE OCEAN WILL END FROM N-S THIS AFTERNOON AS SEAS GRADUALLY
SUBSIDE FROM 4-5FT N/5-6FT S...TO 3-4FT N/4-5FT S.
OTHERWISE...HIGH PRESSURE WILL GRADUALLY SLIDE OFF THE COAST
MONDAY THROUGH THURSDAY. E/SE FLOW AOB 15KT IS EXPECTED
MONDAY/TUESDAY...BEFORE THE WIND SHIFTS TO SSW AOB 15KT BY
WEDNESDAY/THURSDAY AS THE HIGH SLIDES FARTHER OFFSHORE. SEAS
SHOULD AVERAGE 2-3FT DURING THIS TIMEFRAME WITH 1-2FT WAVES.
PERSISTENT ONSHORE FLOW AND HIGH NEARSHORE WAVES WILL ENHANCE THE
THREAT OF RIP CURRENTS TODAY AND POTENTIALLY INTO MONDAY.
&&
.TIDES/COASTAL FLOODING...
TIDAL ANOMALIES WILL GRADUALLY DROP FROM 1.0-1.5 FT ABOVE NORMAL
TO BELOW 1.0 FT ABOVE NORMAL TODAY AS A NE WIND RELAXES. NO TIDAL
FLOODING IS EXPECTED AT THIS TIME. HOWEVER...BISHOPS HEAD AND
LEWISETTA WILL BE CLOSE TO MINOR THRESHOLDS DURING HIGH TIDE THIS
MORNING AND EARLY THIS EVENING.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EDT THIS AFTERNOON FOR ANZ634.
SMALL CRAFT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR ANZ656-
658.
&&
$$
SYNOPSIS...ALB/JDM
NEAR TERM...ALB/JDM
SHORT TERM...ALB/JDM
LONG TERM...LSA
AVIATION...LSA
MARINE...AJZ/LSA
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
449 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 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 141 PM EDT SUN SEP 6 2015
A COLD FRONT AND SHORTWAVE WILL LEAD TO SHOWERS AND THUNDERSTORMS
LATE THIS EVENING INTO TONIGHT. LOW CLOUDS AND SOME FOG WILL DEVELOP
BEHIND THE COLD FRONT...BUT LOW CLOUDS AND FOG SHOULD DISSIPATE MON
MORNING...OR POSSIBLY EARLY AFTERNOON AT KSAW.
&&
.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...TITUS
MARINE...TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
327 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 THROUGH SATURDAY)
ISSUED AT 416 AM EDT SUN SEP 6 2015
MONDAY...THE UPPER LEVEL LOW AND SURFACE LOW WILL REMAIN NEARLY
STATIONARY OVER SASKATCHEWAN/MANITOBA AS THE COLD FRONT PROGRESSES
THROUGH THE EASTERN U.P. THIS WILL FOCUS THE SHOWERS AND
THUNDERSTORMS OVER THE EASTERN AREAS OF THE UPPER PENINSULA THROUGH
THE EARLY AFTERNOON HOURS. THIS TREND CAN BE NOTED IN THE 00Z
GEM/GFS/EC. THE NAM CONTINUES TO BE THE MUCH SLOWER SOLUTION
BRINGING THE COLD FRONT ACROSS THE CENTRAL AND EASTERN U.P. BETWEEN
15Z AND 21Z MONDAY. THIS SOLUTION WOULD BE CAUSE FOR CONCERN AS THIS
WOULD MEAN THE FRONTAL WOULD PASS THROUGH THE CENTRAL AND EAST
DURING PEAK HEATING OF THE DAY...ALLOWING FOR INCREASED
INSTABILITY. THE GEM/GFS/EC MODELS HAVE AROUND 400-600J/KG...BUT THE
NAME...WITH THE SLOWER SOLUTION WOULD HAVE 2000-3000J/KG DURING
FRONTAL PASSAGE. AT THIS POINT...WITH THE NAM BEING THE
OUTLIER...WILL NOT PUT TO MUCH WEIGHT IN THAT SOLUTION AND STICK
WITH THE CHANCE OF SHOWERS AND THUNDERSTORMS DURING THE EARLY
MORNING HOURS CENTRAL AND LATE MORNING HOURS FAR EAST WITH
DIMINISHING TREND IN THE AFTERNOON.
MONDAY NIGHT THROUGH WEDNESDAY...AS HIGH PRESSURE SLIDES ACROSS THE
AREA BEHIND THE FRONT...EXPECT DRY CONDITIONS TO SLIDE OVER MUCH OF
THE UPPER PENINSULA MONDAY NIGHT. THIS WILL BE THE CASE THROUGH
TUESDAY MORNING AS ANTICYCLONIC FLOW AND FAIRLY DRY AIR PUSHES INTO
THE AREA AT THE SAME TIME THAT ZONAL FLOW SLIDES IN ALOFT. TUESDAY
AFTERNOON AND TUESDAY NIGHT MODELS ARE SHOWING A WEAK SURFACE LOW
WILL SLIDE TO THE SOUTH AND EAST OF THE AREA BRINGING A CHANCE OF
SHOWERS TO THE SOUTH CENTRAL PART OF THE U.P. AND THE EASTERN HALF
AS MOISTURE SLOWLY INCREASES. ADDITIONALLY...A LITTLE EXTRA FORCING
MAY COME IN ALOFT AS A SHORTWAVE IS PROGGED TO SLIDE THROUGH THE
AREA AROUND THE SAME TIME. THE BEST FORCING WILL LIKE STAY JUST TO
THE SOUTH AND EAST OF THE AREA...BUT THE CHANCE OF SHOWERS WILL BE
THERE TUESDAY INTO TUESDAY NIGHT. WEDNESDAY...THE SHORTWAVE WILL BE
EAST OF THE AREA WITH DRIER AIR AND HIGH PRESSURE SLIDING IN ONCE
AGAIN ALLOWING FOR ANOTHER BREAK IN THE PRECIPITATION.
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...DIFFERENCES IN SURFACE
PATTERN REMAIN BETWEEN THE EC/GFS...HOWEVER...AT THE UPPER LEVELS
THE TRENDS ARE VERY SIMILAR. THE UPPER LEVEL TRENDS WOULD HAVE THE
ZONAL FLOW WEDNESDAY NIGHT TRENDING TOWARD OVERALL TROUGHING AS A
WAVE SLIDING ACROSS THE CANADIAN PRAIRIES BEGINS TO DEEPEN. BOTH THE
GFS/EC HAVE THE TROUGH SLIDING INTO THE UPPER GREAT LAKES REGION
THURSDAY AFTERNOON INTO THURSDAY NIGHT. THE SURFACE FEATURE
DIFFERENCES COME FROM THE GFS INTENSIFYING A LOW OVER NORTHERN MN
WEDNESDAY NIGHT AND DRAGGING A COLD FRONT THROUGH THE U.P. THURSDAY
AFTERNOON AND THURSDAY NIGHT...WHILE THE EC DEVELOPS THE LOW OVER
SOUTHERN WI AND SHIFTS IT INTO THE LOWER GREAT LAKES. EVEN WITH THE
DIFFERING SURFACE PATTER...THE UPPER LEVEL TROUGHING THAT WILL BE
SLIDING INTO THE AREA WILL PROVIDE ENOUGH SUPPORT FOR A COOLER AND
WETTER WEATHER PATTERN FOR MUCH OF THIS TIME PERIOD. THE BEST CHANCE
FOR SHOWERS WOULD BE THURSDAY INTO THURSDAY NIGHT AS HEIGHTS BEGIN
TO FALL RAPIDLY AS THE UPPER LEVEL 500MB TROUGH AXIS APPROACHES.
FRIDAY INTO SATURDAY...THE PATTERN WILL BE MORE OF AN AUTUMN LIKE
PATTERN DURING THIS TIME PERIOD. THE TROUGH AXIS WILL BE DIRECTLY
OVERHEAD FRIDAY INTO FRIDAY NIGHT ALLOWING FOR MUCH COOLER
TEMPERATURES ALOFT ALONG WITH INCREASED MOISTURE. 850MB TEMPERATURES
ARE PROGGED TO FALL AS LOW AS 1C TO 2C ALLOWING FOR LAKE ENHANCED
RAIN SHOWERS OR DRIZZLE. THIS WOULD ESPECIALLY BE TRUE FOR AREAS
NEAR LAKE SUPERIOR IN THE HIGHER TERRAIN AND FAVORED BY NORTHERLY
FLOW. OVERALL FORCING APPEARS WEAK AND MOISTURE LOOKS TO BE FAIRLY
SHALLOW...WHICH WOULD FAVOR MORE OF A LIGHT RAIN OR DRIZZLE PATTERN
FOR FRIDAY AND FRIDAY NIGHT. FOR SATURDAY...THE TROUGH AXIS SLIDES
FARTHER EAST AND DRY AIR SLIDES INTO THE AREA BRINGING A SLOW END TO
THE PRECIPITATION...HOWEVER...CLOUDS MAY LINGER A BIT LONG AS OFTEN
HAPPENS WITH THAT TYPE OF PATTERN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 141 PM EDT SUN SEP 6 2015
A COLD FRONT AND SHORTWAVE WILL LEAD TO SHOWERS AND THUNDERSTORMS
LATE THIS EVENING INTO TONIGHT. LOW CLOUDS AND SOME FOG WILL DEVELOP
BEHIND THE COLD FRONT...BUT LOW CLOUDS AND FOG SHOULD DISSIPATE MON
MORNING...OR POSSIBLY EARLY AFTERNOON AT KSAW.
&&
.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...KEC
AVIATION...TITUS
MARINE...TITUS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
253 PM CDT SUN SEP 6 2015
.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 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1242 PM CDT SUN SEP 6 2015
A FEW SIGNIFICANT CHANGES TO THE TAFS. FIRST OF ALL...CONFIDENCE
IN THUNDERSTORMS IS DECREASING. THE TWO AREAS OF FORCING FOR
ASCENT ARE ACROSS NORTHERN MN...AND ANOTHER OVER SOUTHEAST MN.
THEREFORE NOT EXPECTING A FOCUSED AREA OF STORM DEVELOPMENT ACROSS
CENTRAL MN...SO HAVE REMOVED THUNDER FROM MOST TAF SITES. THE
SECOND CHANGE WAS SPED UP THE TIMING OF THE NORTHWEST WIND SHIFT
BEHIND THE COLD FRONT. MVFR CEILINGS ARE POSSIBLE WITH THE COLD
FRONT PASSAGE.
KMSP...
THE SYNOPTIC SETUP FOR STORMS IS MARGINAL...AND HIRES MODELS ARE
TRENDING FARTHER NORTH AND SOUTH WITH THE CONVECTION...SO STORMS
MAY SPLIT MSP. HAVE REMOVED THUNDER FROM THE TAFS TO MIRROR THIS
TREND. ALSO SPED UP THE TIMING OF THE WIND SHIFT IN THE WAKE OF A
PASSING COLD FRONT.
/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...JRB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1246 PM CDT SUN SEP 6 2015
.UPDATE...
ISSUED AT 1246 PM CDT SUN SEP 6 2015
THE FRONT HAS INDEED SLOWED ITS FWD PROGRESS. THE FRONT SHOULD
HAVE BEEN THRU BVN-GRI-HDE-PHG BY 17Z. STILL SEE LITTLE HOPE FOR
MUCH MORE THAN A STORM OR TWO THIS AFTERNOON. THE "BEST" CHANCE
WILL BE JUST E OF THE FCST AREA FROM ERN NEB DOWN INTO CNTRL KS OR
ROUGHLY OMA-BIE-CNK-DDC.
UPDATE ISSUED AT 1006 AM CDT SUN SEP 6 2015
THE HWO WAS UPDATED SHORTLY AFTER THE 12Z UPDATE POSTED TO THE SPC
DAY 1 SVR OUTLOOK. REMOVED MENTION OF TORNADO POTENTIAL. THIS
SETUP IS NOT FAVORABLE FOR TOR`S.
THE FRONT IS NOW VISIBLE ON OUR RADAR...ROUGHLY LOCATED FROM
GREELEY-LOUP CITY-OVERTON-ELWOOD. IT`S MOVEMENT IS ESE AT 26 KTS.
IF IT MAINTAINS THIS MVMT...IT WILL BE EXITING THE SE CORNER OF
OUR FCST AREA (HEBRON-BELOIT) BY 1830Z! THAT WOULD EFFECTIVELY END
WHATEVER LITTLE POTENTIAL FOR THUNDER EXISTS.
LOOKING AT THE LATEST RUC/HRRR AND THE 12Z NAM...THEY ALL HAVE THE
CURRENT LOCATION OF THE FRONT...BUT ARE MUCH SLOWER WITH ITS FWD
MVMT. THE 12Z NAM IS 15 KTS AND DOES NOT BRING THE FRONT TO THE SE
FRINGE OF THE FCST AREA UNTIL 00Z. THE 13Z HRRR ACTUALLY SLOWS THE
FRONT DOWN 17Z-19Z ACROSS THE HEART OF THE FCST AREA...THEN IT
RESUMES ITS SE PROGRESS. I JUST DON`T SEE THAT HAPPENING.
FOR WHAT IT`S WORTH...THE 12Z NAM ACTUALLY MAINTAINS CONTINUITY
WITH YESTERDAY`S MODELS...STALLING THE FRONT FROM HEBRON-OSBORNE
LATE THIS AFTERNOON INTO TONIGHT.
GIVEN THE DEEP SW FLOW ALOFT...IT IS QUITE PROBABLE THE FRONT
WILL SLOW ITS FWD PROGRESS...IT`S JUST A MATTER OF HOW SOON AND
WHERE. WILL CONT TO MONITOR...
FOR NOW...WE`LL BE UPDATING THE WIND FCST SHORTLY TO BETTER
REFLECT FRONTAL LOCATION/PASSAGE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 401 AM CDT SUN SEP 6 2015
ANOTHER UNSEASONABLY WARM SEPTEMBER DAY IS ANTICIPATED ACROSS THE
LOCAL AREA THIS AFTERNOON AS A COLD FRONT ACROSS NORTHERN NEBRASKA
WORKS ITS WAY SOUTHEASTWARD. EXPECT SOME ADIABATIC COMPRESSION
AHEAD OF THIS FRONT TO LEAD TO ANOTHER WARM AFTERNOON WITH HIGH
TEMPERATURES IN THE MID 90S FOR MOST AREAS...AND THESE WARM
READINGS ALONG WITH THE ANTICIPATED DECREASING WINDS ASSOCIATED
WITH THE SURFACE TROUGH...WILL MAKE FOR A VERY HOT...HUMID AND
LIKELY UNCOMFORTABLE AFTERNOON FOR THE MAJORITY OF THE FORECAST
AREA.
WHILE THERE WILL BE A SMALL CHANCE FOR SOME SHOWER AND
THUNDERSTORM DEVELOPMENT AHEAD OF THIS FRONT...MOST AREAS WILL
LIKELY REMAIN DRY AS THE FOCUS OF THIS ACTIVITY WILL LIE PRIMARILY
SOUTHEAST OF THE LOCAL AREA. THAT SAID...IF STORMS ARE ABLE TO
INITIATE THIS AFTERNOON...GOOD INSTABILITY SHOULD ALLOW THESE
STORMS TO RAPIDLY INTENSIFY...POSSIBLY PRODUCING STRONG
THUNDERSTORM WIND GUSTS AND SMALL HAIL. THANKS TO FAIRLY MARGINAL
SHEAR...THE TORNADO RISK WILL BE LOW...ALBEIT NOT COMPLETELY NON-
EXISTENT THANKS TO THE PRESENCE OF THE PASSING FRONTAL BOUNDARY.
NOT SURPRISINGLY... ROUGHLY THE EASTERN HALF OF THE FORECAST AREA
IS HIGHLIGHTED IN A MARGINAL RISK FOR SEVERE WEATHER FROM THE
STORM PREDICTION CENTER FOR TODAY...INCLUDING A 2 PERCENT RISK FOR
TORNADOES.
WHILE THERE MAY BE A BRIEF FEW HOURS OF INCREASED NORTHERLY WINDS
BEHIND THE FRONTAL BOUNDARY...ONCE THIS SURGE OF STRONGER WINDS
DIMINISHES...LIGHTER NORTHERLY WINDS AND MUCH COOLER TEMPERATURES
AREA EXPECTED IN THE WAKE OF THIS APPROACHING FRONT. WHILE NOT
UNSEASONABLY COOL...TEMPERATURES ARE FORECAST TO FALL INTO THE
UPPER 50S ACROSS OUR NORTHERN COUNTIES...AND INTO MIDDLE 60S
ACROSS NORTH CENTRAL KANSAS. NORMAL HIGH TEMPERATURES FOR THE TRI-
CITIES THIS TIME OF YEAR ARE IN THE MIDDLE 50S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 401 AM CDT SUN SEP 6 2015
BIGGEST ISSUE WILL BE GETTING A GOOD HANDLE ON HOW FAST COOLER
AND DRIER AIR MOVES IN.
AT THE SYNOPTIC LEVEL...A SHORTWAVE TROUGH WILL ENTER THE PLAINS
BY AFTERNOON/EVENING AND COULD HELP SPAWN SOME THUNDERSTORMS ALONG
AND NORTH OF A STALLED SURFACE BOUNDARY NEAR THE SOUTHERN FRINGE
OF THE CWA. SOMEWHAT MODEST UPPER LEVEL FLOW AT THE BASE OF THE
TROUGH WILL MOVE INTO OUR REGION...AND WITH INSOLATION...COULD
SPARK SOME STRONG STORMS AS INSTABILITY INCREASES...ESPECIALLY
SOUTH AND EAST.
YET ANOTHER WAVE IS FORECAST TO SWING THROUGH ON TUESDAY AND WITH
A BOUNDARY POTENTIALLY NEARBY IN THE SOUTH...WE COULD GET MORE
THUNDERSTORMS...BUT COOLER TEMPERATURES ARE EXPECTED WITH HIGHS
ONLY REACHING NEAR 80 FOR MUCH OF SOUTH CENTRAL NEBRASKA...AND
PERHAPS MID 80S IN NORTH CENTRAL KANSAS AS COOLER AND DRIER AIR
CONTINUES TO MOVE IN. WITH COOLER AND DRIER AIR COMES LESS
INSTABILITY...SO STRONG STORMS ARE NOT AS BIG OF A CONCERN.
SHOWERS AND THUNDERSTORMS ARE A POSSIBILITY THROUGH FRIDAY NIGHT
...AS A SERIES OF WAVES MOVE BY WITHIN NORTHWEST FLOW...WITH
MODELS TRENDING TOWARD LATER BUILDING OF THE WESTERN RIDGE TO THE
EAST AS COMPARED TO PREVIOUS FORECASTS. BY SATURDAY...WE SHOULD
BEGIN DRYING OUT AS THE UPPER RIDGE BECOMES MORE PROMINENT IN OUR
AREA AS A COOLING TREND CONTINUES THROUGH THE WORK WEEK AND INTO
THE WEEKEND. WENT WITH CONSRAW FOR HIGH TEMPERATURES FRIDAY AND
ADJMEN FOR LOWS TUESDAY MORNING AS A STARTING POINT...AS
SUPERBLEND APPEARS ABNORMALLY WARM FOR THIS PERIOD.
&&
.AVIATION...(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z MON AFTERNOON)
ISSUED AT 1246 PM CDT SUN SEP 6 2015
SIGNIFICANT WX ISSUES: COLD FRONTAL PASSAGE THIS AFTERNOON. WSHFT
TO NW-N 18Z-20Z.
THIS AFTERNOON: VFR WITH SCT-BKN ALTOCU AROUND 14K FT. SW WINDS
UNDER 10 KTS SHIFT TO NW AND EVENTUALLY N AND INCREASE WITH
OCCASIONAL GUSTS TO NEAR 20 KTS. CONFIDENCE: HIGH
TONIGHT: VFR WITH INCREASING CIRROSTRATUS 20-25K FT AFTER 05Z.
WINDS DIMINISH AND BECOME NE BELOW 10 KTS. CONFIDENCE: HIGH
MON THRU 18Z: MULTI-LAYERED VFR CIGS GRADUALLY DESCEND TO NEAR 14K
FT. LIGHT NE WINDS GRADUALLY BECOME E OR ESE. CONFIDENCE: HIGH
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...ROSSI
LONG TERM...HEINLEIN
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
912 AM 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...
QUICK UPDATE THIS MORNING TO ADJUST CLOUD COVER AND WHERE THE BEST
CHANCE OF LIGHT RAIN MAY OCCUR WITHIN THE NEXT FEW HOURS. LIGHT RAIN
ACROSS SOUTHWEST ARIZONA IS MOVING NORTH-NORTHEAST TOWARD SOUTHERN
MOHAVE COUNTY. ADDED A SLIGHT CHANCE OF A SHOWER THERE, BUT NOT
EXPECTING MUCH QPF FROM THIS ACTIVITY. OUR ATTENTION THEN TURNS TO
WHAT MAY DEVELOP THIS AFTERNOON.
MOISTURE HAS INCREASED OVER THE LAST 24 HOURS, MAINLY EAST AND SOUTH
OF LAS VEGAS. AS OF THIS WRITING THE DEWPOINT AT MCCARRAN IS IN THE
UPPER 20S WITH A 0.10 DROP IN TOTAL PW SINCE YESTERDAY BASED ON THE
12Z KVEF SOUNDING. THE MOISTURE BOUNDARY AT THE SURFACE AND LOWER
ATMOSPHERE RUNS BASICALLY ALONG THE COLORADO RIVER, WITH INCREASING
MOISTURE EAST AND SOUTH. MOHAVE COUNTY WILL HAVE THE BEST CHANCE OF
SHOWER/STORM DEVELOPMENT TODAY. AREAS WEST OF THE COLORADO RIVER
COULD SEE SOME DEVELOPMENT, BUT ANY CELLS THAT DEVELOP WOULD HAVE A
BETTER CHANCE OF BEING SMALL AND NOT SURE THEY WILL PRODUCE MUCH, IF
ANY QPF. LOOKING AT THE MOISTURE BOUNDARY AROUND 850MB THE LAST FEW
DAYS, ANY CELLS DEVELOPING NEAR THE WESTERN EDGE HAVE STRUGGLED AND
BELIEVE THAT COULD BE THE CASE AGAIN TODAY, WHICH WOULD BE ACROSS
THE EASTERN HALF CLARK AND FAR EASTERN SAN BERNARDINO. THESE,
HOWEVER, COULD PRODUCE SOME GUSTY OUTFLOW WINDS SINCE THEY WOULD
TEND TO BE DRIER CONVECTION.
QUITE A FEW RUNS OF THE HRRR HAVE INDICATED THIS SCENARIO, WITH VERY
MINIMAL DEVELOPMENT IN CLARK AND SAN BERNARDINO. SOME OF THE LATEST
12Z MODELS ARE ALSO INDICATING LITTLE TO NO DEVELOPMENT IN THESE
SAME AREAS. WE WILL NEED MOISTURE ADVECTION AND SOME EROSION OF
SLIGHT CAPPING ALOFT TO CONTINUE IN ORDER TO DESTABILIZE THE
ATMOSPHERE AND MAKE IT MORE FAVORABLE, BUT THE LATEST HRRR DOES NOT
REALLY INDICATE THIS. OVERALL OUR CURRENT FORECAST LOOKS PRETTY GOOD
WITH MAINLY SLIGHT CHANCES ACROSS PORTIONS OF CLARK AND SAN BERN
COUNTIES, BUT MAY NEED TO MAKE SOME ADJUSTMENTS LATER TODAY, AS WE
CONTINUE TO MONITOR MOISTURE TRENDS.
&&
.PREVIOUS DISCUSSION...
331 AM PDT SUN SEP 6 2015
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT.
A LONE DECAYING SHOWER WAS MOVING NORTHEAST ACROSS THE PLATEAU
COUNTRY OF MOHAVE COUNTY EARLY THIS MORNING. HOWEVER, THIS INDICATES
THE ATMOSPHERE IS NOT SO DRY AND STABLE AND THUS SOME ADJUSTMENTS
WERE MADE TO THE FORECAST FOR TODAY. IF YOU ARE IN THE WESTERN AND
NORTHERN PARTS OF THE AREA TODAY, THIS WILL STILL BE A FANTASTIC DAY
FOR THIS TIME OF YEAR WITH DRY CONDITIONS COURTESY OF A SOUTHWEST
FLOW ALOFT AND BELOW NORMAL HIGH TEMPERATURES AND RELATIVELY LIGHT
WINDS MUCH OF THE DAY. SUNSHINE WILL BE PLENTIFUL IN THESE AREAS.
THE ALLEGED SWEEP OUT OF THE MOISTURE ACROSS THE SOUTHEASTERN PARTS
OF THE AREA THAT WAS SHOWN FOR DAYS HAS NEVER TAKEN PLACE. THERE IS
A MID/UPPER LEVEL TROUGH DIGGING SOUTH ACROSS NEVADA THIS MORNING
BUT THIS FEATURE WILL MAKE LITTLE HEADWAY SOUTH AND WILL JUST GET
HUNG UP ACROSS SOUTHERN NEVADA AND SLOWLY BECOME PARALLEL ENOUGH TO
THE FLOW ALOFT THAT IT WASHES OUT. THUS THE FEED OF TROPICAL
MOISTURE INTO ARIZONA WILL NOW HAVE A WINDOW TO OOZE A BIT FURTHER
WEST AND NORTH. THE QUESTION IS HOW FAR IN BOTH DIRECTIONS. THE
OPERATIONAL GFS HAS BEEN THE WETTEST MODEL AND IN ALL RESPECT NOT
DONE TOO BAD HANDLING THIS PATTERN. THUS IT WAS LEANED TOWARD WITH
THE FORECAST FOR THIS MORNING. THE OPERATIONAL ECMWF IS SORT OF IN
THE MIDDLE WITH THE WRF INITIALLY DRIER THEN WETTER.
IPW SENSORS SHOW PWATS BETWEEN A HALF AN INCH AND AN INCH ACROSS THE
SOUTHEAST THIRD OF THE AREA THIS MORNING. THESE VALUES ARE FORECAST
TO RISE THROUGH THE DAY TO BETWEEN 0.75 AND 1.30 INCH. THUS THIS
WILL OPEN THE DOOR FOR AREAS WITHIN ABOUT 25 MILES WEST OF THE
COLORADO RIVER VALLEY ON EAST TO SEE SHOWERS AND THUNDERSTORMS
AROUND THIS AFTERNOON AND EVENING. THE HRRR MODEL RAPIDLY SETS OFF
CONVECTION AROUND 11 AM OR SO TODAY IN THE PLATEAU COUNTRY OF MOHAVE
COUNTY, THEN DEVELOPS MORE ACTIVITY FURTHER SOUTH AND WEST. GIVEN
THIS, POPS WERE RAISED IN MOHAVE COUNTY BY NEARLY DOUBLE AND THE
MENTION OF SHOWERS AND THUNDERSTORMS WAS ADDED IN AS FAR NORTH AS
MESQUITE AND THE MOAPA RIVER VALLEY AND AS FAR WEST AS LAS VEGAS,
SEARCHLIGHT AND VIDAL JUNCTION. THE FLOW TODAY IS FROM THE SOUTH, SO
FOR THE LAS VEGAS VALLEY, ANY ACTIVITY THAT GETS GOING IN THE MOJAVE
NATIONAL PRESERVE OR THE MCCULLOUGH RANGE WILL HAVE THE POTENTIAL TO
WORK INTO THE VALLEY. THE BEST ODDS IN THE LAS VEGAS VALLEY WILL BE
IN THE SOUTHEAST PART OF THE VALLEY. THE WEST AND NORTH SIDES MAY
SEE NOTHING AT ALL. THE MODELS DO NOT BRING MUCH MOISTURE INTO THE
SPRING MOUNTAINS, SO WE WILL KEEP THEM DRY. IF YOU PLAN TO VENTURE
OUT TO THE LAKE TODAY, PLEASE KEEP AWARE OF THE CLOUDS AND HAVE A
WAY TO GET UPDATES ON THE WEATHER AS THE SITUATION MAY RAPIDLY
CHANGE. THE MAIN CONCERN TODAY WITH STORMS WILL BE FLASH FLOODING IN
ANY STRONGER OR TRAINING ACTIVITY AS WELL AS GUSTY WINDS. DCAPE
VALUES ON THE GFS ARE IMPRESSIVE SHOWING 1000-2000 J/KG TODAY WITH
THE HIGHEST VALUES OVER LAKE MEAD SOUTHWEST TOWARD SEARCHLIGHT. BY
CONTRAST THE ECMWF SHOWS VALUES OF 300 J/KG AT BEST.
ACTIVITY MAY NOT BE SO QUICK TO END TONIGHT AND IF THE GFS IS
CORRECT WE WILL SEE SHOWERS AND THUNDERSTORMS LAST OVERNIGHT. FOR
NOW, I NUDGED UP POPS A LITTLE MAINLY IN MOHAVE COUNTY. LOWS TONIGHT
WILL BE AT OR ABOVE WHAT WE SEE THIS MORNING.
TEMPS WILL BEGIN TO RISE ON MONDAY AND WARM FURTHER ON TUESDAY. THE
MAIN CHALLENGE WILL BE HOW MUCH MOISTURE IS AROUND IN THE MOJAVE
DESERT AND THUS CLOUD COVER. WE STILL HAVE LAS VEGAS RETURNING BACK
INTO THE TRIPLE DIGITS AT MCCARRAN ON TUESDAY AS THE WARMER ECMWF
AND GFS NUMBERS HAVE BEEN DOING BETTER LATELY.
THE FLOW ALOFT REMAINS SOUTHWEST TO WEST WHICH WILL KEEP WESTERN AND
NORTHERN AREAS DRY, HOWEVER, WE MAINTAINED SHOWERS AND THUNDERSTORMS
IN NEARLY SIMILAR AREAS TO WHAT WE HAVE IN TODAY FOR LABOR DAY. THE
BEST CHANCES WILL REMAIN IN MOHAVE COUNTY. AWAY FROM HEATING AND
TERRAIN AND ANY OLD OUTFLOW BOUNDARIES AROUND THE ONLY LARGE SCALE
FEATURE TO DRIVE CONVECTION WILL BE A 60 KT+ JET STREAM AT 250 MB
MOVING OVERHEAD ASSISTING IN LIFT ON MONDAY. THIS FEATURE MOVES AWAY
BY TUESDAY. THE WRF STARTS TO SHOW BETTER INSTABILITY AND MOISTURE
FURTHER WEST ON TUESDAY WITH ACTIVITY POSSIBLE AS FAR WEST AS THE
MORONGO BASIN. FOR NOW, I KEPT THINGS DRY OUT THAT WAY AS WELL AS
WEST OF THE COLORADO RIVER AS BOTH THE GFS AND ECMWF ARE DRIER AND
MORE STABLE. HOWEVER, WE WILL HAVE TO SEE HOW THINGS PLAY OUT AND
MAY NEED TO ADJUST THE FORECAST.
.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.
&&
.AVIATION...FOR MCCARRAN...WINDS WILL REMAIN SOUTHERLY THROUGH THIS
EVENING. BETWEEN 14Z AND 19Z WINDS WILL FAVOR A DIRECTION BETWEEN
130 AND 170 DEGREES WHICH COULD CAUSE CONFIGURATION ISSUES, HOWEVER,
SPEEDS ARE EXPECTED TO BE 4-8 KTS. WINDS WILL INCREASE AROUND 22Z
TODAY TO 8-12 KTS WITH GUSTS TO 18 KTS THEN DECREASE BETWEEN 02Z AND
04Z THIS EVENING. FEW-SCT CLOUDS AOA 10K-15K FEET. THERE IS THE
POSSIBILITY SHRA/TSRA MAY GET CLOSE ENOUGH TO THE SOUTH END OF THE
VALLEY THAT OUTFLOW BOUNDARIES COULD DEVELOP AND IMPACT WIND SPEED
AND DIRECTIONS. THERE IS A VERY SMALL CHANCE THAT A SHRA/TSRA COULD
EVEN DIRECTLY IMPACT THE TERMINAL BUT CONFIDENCE IS TOO LOW TO
INCLUDE IN THE TAF AT THIS TIME. ISOLATED SHRA/TSRA WILL BE AROUND
AFTER 18Z TODAY IN THE PEACH SPRINGS AND TO A LESSER EXTENT THE
MORMON MESA CORRIDORS.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...WINDS WILL MAINLY BE SOUTH TO SOUTHWEST AT 6-12 KTS
WITH GUSTS OF 12-20 KTS THIS AFTERNOON AND EARLY EVENING. BETWEEN
02Z AND 04Z MONDAY WINDS SHOULD DECREASE AND TREND TOWARD TYPICAL
DIURNAL DIRECTIONAL TRENDS FOR THE REST OF THE NIGHT. THE EXCEPTION
WILL BE NEAR ANY SHRA/TSRA WHERE GUSTY AND ERRATIC WINDS ARE
POSSIBLE. SHRA/TSRA ARE POSSIBLE TODAY AFTER 18Z AND MAINLY ENDING
BY 06Z MONDAY 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.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
UPDATE...PADDOCK
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 ALBUQUERQUE NM
318 PM MDT SUN SEP 6 2015
.SYNOPSIS...
SHOWERS AND THUNDESTORMS 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.
&&
.AVIATION...
18Z TAF CYCLE
SOME DRIER AIR PUSHING INTO NW NM BUT MAINLY IN THE MID LEVELS SO
EXPECT CONVECTION TO DEVELOP AFT 18Z. SHORT TERM MODELS INDICATE
MOST NUMEROUS DEVELOPMENT TO BE SOUTH OF INTERSTATE 40...WITH MORE
ISOLD ACTIVITTY TO THE NORTH. CELL MOVEMENT WILL BE GENERALLY TO
THE NORTHEAST. MTS OCCASIONALLY OBSCD IN BRIEF MVFR CIGS/VSBYS IN
THE STRONGER STORMS. SFC WND GUSTS TO 40KT POSSIBLE AS WELL.
EXPECT CONVECTION TO DIMINISH 03Z TO 06Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 55 85 56 86 / 5 10 10 0
DULCE........................... 44 78 45 80 / 10 10 10 10
CUBA............................ 50 76 51 78 / 10 20 20 5
GALLUP.......................... 48 81 50 83 / 20 20 20 10
EL MORRO........................ 46 75 50 79 / 30 30 40 20
GRANTS.......................... 48 79 49 82 / 20 20 30 10
QUEMADO......................... 49 75 52 78 / 30 40 40 20
GLENWOOD........................ 58 83 57 82 / 20 30 30 30
CHAMA........................... 44 75 44 76 / 10 20 10 10
LOS ALAMOS...................... 57 79 57 81 / 10 20 30 5
PECOS........................... 54 77 55 78 / 10 20 20 10
CERRO/QUESTA.................... 49 76 49 76 / 5 10 10 10
RED RIVER....................... 43 69 43 69 / 10 20 20 20
ANGEL FIRE...................... 47 70 47 70 / 10 20 20 20
TAOS............................ 48 80 48 79 / 5 10 10 5
MORA............................ 51 75 52 75 / 10 20 20 20
ESPANOLA........................ 52 84 55 85 / 10 10 20 0
SANTA FE........................ 55 79 57 80 / 10 10 20 10
SANTA FE AIRPORT................ 54 84 56 85 / 10 10 10 5
ALBUQUERQUE FOOTHILLS........... 61 83 61 86 / 10 20 20 0
ALBUQUERQUE HEIGHTS............. 62 85 63 88 / 10 10 10 0
ALBUQUERQUE VALLEY.............. 59 87 62 89 / 10 10 10 0
ALBUQUERQUE WEST MESA........... 60 86 62 88 / 10 10 10 0
LOS LUNAS....................... 59 88 60 90 / 10 10 10 0
RIO RANCHO...................... 59 87 61 89 / 10 10 10 0
SOCORRO......................... 63 89 62 89 / 20 30 30 5
SANDIA PARK/CEDAR CREST......... 56 81 58 82 / 10 20 20 5
TIJERAS......................... 57 83 58 84 / 10 20 20 5
MORIARTY/ESTANCIA............... 52 85 54 85 / 10 20 20 5
CLINES CORNERS.................. 55 81 55 81 / 20 30 20 10
GRAN QUIVIRA.................... 58 82 58 83 / 10 30 30 10
CARRIZOZO....................... 63 86 62 87 / 20 20 30 20
RUIDOSO......................... 59 78 59 78 / 40 40 50 20
CAPULIN......................... 53 85 54 77 / 5 5 10 20
RATON........................... 53 87 53 84 / 5 10 10 20
SPRINGER........................ 54 87 54 84 / 5 10 10 20
LAS VEGAS....................... 54 83 54 81 / 10 20 20 10
CLAYTON......................... 64 91 62 85 / 5 20 10 10
ROY............................. 59 86 59 83 / 10 20 20 10
CONCHAS......................... 65 94 65 92 / 10 20 20 10
SANTA ROSA...................... 64 91 64 90 / 10 30 30 10
TUCUMCARI....................... 66 96 65 93 / 20 30 30 10
CLOVIS.......................... 66 92 65 92 / 20 30 20 20
PORTALES........................ 67 91 66 91 / 20 30 20 20
FORT SUMNER..................... 66 92 66 91 / 20 30 30 10
ROSWELL......................... 68 94 67 94 / 20 30 20 10
PICACHO......................... 64 89 63 89 / 20 30 40 20
ELK............................. 63 80 62 81 / 40 30 40 20
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
34
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
124 PM EDT SUN SEP 6 2015
.SYNOPSIS...
HIGH PRESSURE EXPANDING FROM THE NORTH WILL COMBINE WITH DEEP
MOISTURE OFF THE ATLANTIC TO PRODUCE COOLER AND SHOWERY WEATHER
FOR THE NEXT FEW DAYS. THE HIGH WILL RETREAT ON TUESDAY ALLOWING
FOR A RETURN OF SEASONABLE WEATHER. LATE SUMMER CONDITIONS WILL
RETURN WEDNESDAY AND THURSDAY AHEAD OF A COLD FRONT APPROACHING
LATE IN THE WEEK. THE FRONT MAY STALL OVER THE AREA NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 111 PM SUNDAY...MORNING CLOUDS HAVE STYMIED SURFACE WARMING
WITH UPPER 70S TO LOWER 80S EARLY THIS AFTERNOON. LATEST VISIBLE
SATELLITE TRENDS SUGGEST DESPITE CONSIDERABLE COVERAGE...BREAKS
AND THINNING OF CLOUDS WILL ALLOW SURFACE BASED CAPES TO RISE.
SEVERAL OTHER FACTORS REMAIN SUPPORTIVE OF SHOWERS AND ISOLATED
TSTMS ACROSS OUR LAND ZONES TODAY SO NO CHANGES PLANNED TO SCT POP
VALUES...AND RAIN HEAVY AT TIME LATER THIS AFTERNOON AS 2+ INCH
PWAT VALUES EDGE INTO THE COASTAL INTERIOR. THE LEADING EDGE OF
THE HIGH PRECIPITABLE WATERS MAY BECOME PAIRED WITH A ZONE OF SEA
BREEZE CONVERGENCE BY 19Z-20Z/3P-4P. PREVIOUS DISCUSSION FOLLOWS.
LATEST TOTAL PRECIPITABLE WATER DATA BLENDED FROM AMSU AND SSM/I
SATELLITE SENSORS SHOWS 52MM/2.05" IMPINGING THE COAST FROM THE
WESTERN ATLANTIC...WHILE A LITTLE FARTHER WEST OVER CENTRAL NC
POCKETS OF 34MM/1.3 INCHES WERE DETECTED. MOST RECENT KLTX VAD
WIND PROFILE PINGS SHOW DEEP 15KT- 30KT EAST WIND FLOW FROM THE
SURFACE TO 22 THOUSAND FEET...WITH PEAK SPEEDS IN THE H7-H5 LAYER.
WIDESPREAD STRATIFORM RAINFALL BORN OFF TOWERING GULF-STREAM
CUMULONIMBUS WILL EDGE SLOWLY WESTWARD INTO THE CAPE FEAR REGION.
EMBEDDED POCKETS OF CONVECTION WILL MARK THIS VEIL OF -RA.
AS WE TRANSITION INTO AFTERNOON AND MARINE BUOYANCY WANES...ZONES
OF DIFFERENTIAL LAND HEATING COUPLED WITH LOW-LEVEL SEA BREEZE
CONVERGENCE OUGHT TO BE SUFFICIENT TO PROMPT REGENERATION OR
REINTENSIFICATION OF SHOWERS INLAND DURING THE RISE OF DIURNAL
HEATING. ADDITIONALLY IT APPEARS AN H5-H7 VORTICITY MAXIMA WILL
TRACK SE TO NW OVER NE SC AND SE NC THROUGH AFTERNOON. STORM
MOTION AND POTENTIAL CELL-TRAINING COULD LEAD TO ISOLATED
EPISODES OF LOCALIZED FLOODING. WILL NEED TO RE-EXAMINE POP TRENDS
THIS EVENING AS SOME RECENT MODEL DATA SHOWS SUBSIDENCE IN WAKE OF
THE UPPER IMPULSE CURRENTLY MOVING NW INTO OUR AREA...WHICH MAY
RESULT IN A LAND LULL PRIOR TO AN UPTICK IN MARINE ACTIVITY INTO
VERY EARLY MONDAY.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 AM SUNDAY...SLOWLY RETROGRADING AND FILLING MID-LEVEL
TROUGH WILL MAINTAIN COOL AND UNSETTLED WEATHER MUCH OF THE SHORT
TERM...BUT IMPROVEMENT IS EXPECTED LATE IN THE PERIOD.
MID-LEVEL CLOSED LOW WILL DRIFT SLOWLY WESTWARD ACROSS THE GULF
COAST MONDAY AND THEN WEAKEN AND OPEN INTO A TROUGH TUESDAY. BENEATH
THIS FEATURE...A COASTAL/SURFACE TROUGH WILL ADVECT WESTWARD ACROSS
THE AREA MONDAY AND THIS WILL SERVE AS A FOCUS FOR CONVECTION WITHIN
AN UNSTABLE ATMOSPHERE THANKS TO STEEPENED ML-LAPSE RATES AND VERY
HIGH PWATS APPROACHING 2 INCHES. CAPE PROFILES ARE NARROW AND
FORCING ALOFT IS WEAK...BUT THIS COULD ACTUALLY INCREASE THE HEAVY
RAINFALL POTENTIAL THANKS TO EFFICIENT WARM RAIN PROCESSES IN A DEEP
WARM CLOUD LAYER. DO NOT EXPECT WIDESPREAD OR STRONG
CONVECTION...AND THE BEST CHANCE WILL BE ACROSS THE EASTERN HALF OF
THE CWA...BUT SCATTERED SHOWERS AND TSTMS WITH PERIODS OF HEAVY RAIN
ARE EXPECTED ON MONDAY. TEMPS WILL BE LIMITED BY CLOUDS AND
CONVECTION...AND HIGHS WILL LIKELY REMAIN SLIGHTLY BELOW CLIMO...LOW
80S AT THE COAST AND MID 80S WELL INLAND. LOWS WILL BE ABOVE CLIMO
HOWEVER AS COOLING GETS INHIBITED...WITH MINS DROPPING ONLY TO
AROUND 70...LOW 70S AT THE COAST.
TUESDAY IS THE TRANSITION DAY BACK TO MORE LATE-SUMMER LIKE WEATHER.
UPPER TROUGH WILL HAVE RETROGRADED WELL BACK TOWARDS LOUISIANA AS A
MID-LEVEL RIDGE BUILDS NORTH FROM NEAR FLORIDA. THIS WILL ERODE THE
SURFACE TROUGH AND...SURFACE HIGH PRESSURE STRENGTHENING BENEATH THE
RIDGE WILL DRIVE INCREASING RETURN FLOW AND S/SW WINDS ACROSS THE
EASTERN CAROLINAS. THIS COMBINED WITH BUILDING THICKNESSES WILL
DRIVE TEMPERATURES BACK TO SEASONABLE LEVELS IN THE MID TO UPR
80S...WITH MORE TYPICAL DIURNAL CONVECTION CHANCES...FOCUSED
PRIMARILY ALONG THE SEA BREEZE AND PIEDMONT TROUGH. TSTMS WILL WANE
DIURNALLY AND LOWS TUESDAY NIGHT WILL DROP AGAIN TO A DEGREE OR TWO
EITHER SIDE OF 70.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 300 AM SUNDAY...A RETURN TO LATE-SUMMER WEATHER EXPECTED FOR
THE LATTER HALF OF THE UPCOMING WEEK...BUT AS HEAT AND HUMIDITY
RETURN...SHOWER AND TSTM POTENTIAL WILL ALSO INCREASE. MID-LEVEL
RIDGE BLOSSOMING UP FROM FLORIDA WILL EXPAND TO OFF THE NEW ENGLAND
COAST...BUT MAINTAIN ITS AXIS EAST OF THE LOCAL AREA. AT THE SAME
TIME...SURFACE HIGH PRESSURE WILL STRENGTHEN OFFSHORE. THIS WILL
LEAD TO ABOVE NORMAL TEMPERATURES WITH MANY LOCATIONS REACHING
TOWARDS 90 EACH DAY. AT THE SAME TIME...INCREASING HUMIDITY WILL
LEAD TO HIGHER INSTABILITY AND SHOWERS AND TSTMS WILL BECOME
SCATTERED EACH AFTN...EVEN BENEATH SUBTLE SUBSIDENCE BENEATH THE
RIDGE. AS THE WKND APPROACHES...A COLD FRONT WILL DIG DOWN THROUGH
THE EASTERN THIRD OF THE COUNTRY...DRIVEN BY A STRONG VORT IMPULSE
ROTATING THROUGH THE GREAT LAKES. THIS WILL BRING A GOOD CHANCE FOR
TSTMS SATURDAY...BUT NOT TOO MUCH OF AN AIR MASS CHANGE AS THIS
FRONT TRIES TO STALL ACROSS THE CAROLINAS NEXT WKND.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 18Z...WE HAVE HAD STABLE CONDITIONS ALL MORNING WITH IFR CEILINGS.
THE HRRR MODEL HAS BEEN TRENDING DOWNWARD DUE TO THE LACK OF SOLAR
INSOLATION. STILL THINK THE INLAND TERMINALS MAY SEE SOME VCTS LATER
IN THE AFTERNOON AS THE ATMOSPHERE FINALLY RELOADS. LOOK FOR MVFR CEILINGS
TO GRADUALLY RISE TO VFR OR SCATTER ALTOGETHER. THIS EVENING...DIMINISHING
CONVECTION WITH IFR CEILINGS RETURNING AFTER MIDNIGHT WITH NORTHEAST
FLOW. SLOWLY IMPROVING CEILINGS ON MONDAY.
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 111 PM SUNDAY...HIGH PRESSURE WILL MAINTAIN A STEADY
NORTHEAST TO EAST BREEZE ACROSS THE WATERS TODAY AND TONIGHT. A
WEAK TROUGH OF LOW PRESSURE EXTENDING EAST TO WEST OFF THE GA/FL
COAST WILL HELP TO SQUEEZE THE PRESSURE GRADIENT ENOUGH TO KEEP
WIND SPEEDS NEAR 15 KNOTS THROUGH THE PERIOD...WITH OCCASIONAL
GUSTS TO 20 KT. WINDS VARIABLE AND GUSTY WINDS NEAR ISOLATED
THUNDERSTORMS. MARINERS SHOULD BE PREPARED FOR LOWERED VSBYS AND
FREQUENT LIGHTNING AS WELL.
SEAS CURRENTLY AROUND 3 FEET IN OPEN WATERS MAY OCCASIONALLY BUILD
TO 4 FEET BEYOND 15 MILES FROM SHORE...PARTICULARLY TONIGHT...WITH
DOMINANT WAVE PERIODS OF 4-5 SECONDS MUCH OF TODAY.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 AM SUNDAY...HIGH PRESSURE RIDGING DOWN THE COAST WILL BE
ACCOMPANIED BY A SURGE ON MONDAY...WITH NE WINDS PERSISTING AROUND
15 KTS INTO MONDAY NIGHT. LATE MONDAY...AND THEN ESPECIALLY ON
TUESDAY...THIS HIGH PRESSURE WILL WEAKEN AND RETREAT AS HIGH
PRESSURE OFF THE EAST COAST OF FL BECOMES THE DOMINANT SYNOPTIC
FEATURE. THIS WILL BRING A DECREASE IN WIND SPEEDS MONDAY NIGHT INTO
TUESDAY...ALONG WITH A SLOW VEERING TO EAST...THEN SOUTH...AND
FINALLY SETTLING ON SW LATE TUESDAY...ALL WITH SPEEDS OF 10 KTS OR
LESS. WAVE HEIGHTS WILL BE HIGHEST THIS PERIOD ON MONDAY AS A NE
WIND CHOP DRIVES 2-4 FT SEAS. WAVES WILL DEAMPLIFY BEGINNING MONDAY
NIGHT DOWN TO 1-2 FT...AND PERSIST AT THESE AMPLITUDES TUESDAY.
LONG TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 300 AM SUNDAY...HIGH PRESSURE EXPANDING OFF THE EAST COAST OF
FLORIDA WILL CONTROL THE SYNOPTIC WINDS ACROSS THE WATERS MID-TO-
LATE WEEK. RETURN FLOW AROUND THIS FEATURE WILL CREATE SW
WINDS...WITH SPEEDS PRIMARILY AROUND 10 KTS. THE EXCEPTION TO THIS
WILL BE LATE THURSDAY WHEN THE GRADIENT WILL BEGIN TO TIGHTEN AHEAD
OF AN APPROACHING COLD FRONT. WHILE THIS WILL MAINTAIN THE SW WIND
DIRECTION...SPEEDS WILL RISE TO 15 KTS OR MORE AT THE END OF THE
PERIOD. WAVE HEIGHTS WILL REMAIN LOW-AMPLITUDE BOTH DAYS WITH A
SPECTRUM COMPRISED OF A SW WIND WAVE AND LONGER PERIOD SE GROUND
SWELL. SEAS OF 1-2 FT WILL BE MOST LIKELY WEDNESDAY AND
THURSDAY...WITH SOME 3 FTERS DEVELOPING LATE AS THE WINDS INCREASE
AHEAD OF THE COLD FRONT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JDW/MJC
NEAR TERM...MJC
SHORT TERM...JDW
LONG TERM...JDW
MARINE...MJC/TRA/JDW
AVIATION...DL
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
100 PM CDT SUN SEP 6 2015
.UPDATE...
ISSUED AT 1255 PM CDT SUN SEP 6 2015
NO SIGNIFICANT UPDATES PLANNED FOR THE EARLY AFTERNOON. SCATTERED
SHOWERS AND THUNDERSTORMS SHOULD PERSIST ACROSS THE SOUTHERN RRV
AND INTO WEST CENTRAL AND NORTHWEST MINNESOTA INTO MID
AFTERNOON... WITH AN INCREASE IN ACTIVITY EXPECTED AS DAYTIME
HEATING PEAKS ...AHEAD OF THE QUASISTATIONARY FRONT... IN CENTRAL
AND NORTHCENTRAL MN LAKES COUNTRY.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 340 AM CDT SUN SEP 6 2015
FORECAST CHALLENGE FOR THE SHORT TERM WILL BE ONGOING
CONVECTION EXITING THE CWA TO THE EAST AND ENTERING THE CWA
TO THE WEST. THE WESTERN ACTIVITY IS ASSOCIATED WITH A SFC
TROF/FRONT ROUGHLY ALONG A NORTHGATE TO MINOT TO STEELE TO
ASHLEY LINE...WITH MAJORITY OF CONVECTION IN N CNTRL ND.
HRRR HAS A DECENT HANDLE ON WRN ACTIVITY BUT MAY BE A BIT TOO
FAR WEST...IN GENERAL CLIPPING THE FAR NORTHWESTERN PORTION OF
THE CWA. WILL FOLLOW HRRR GUIDANCE BUT BRING CATEGORICAL POPS
FURTHER EAST AND JUST WEST OF DEVILS LAKE. HRRR DOES LIFT THIS
ACTIVITY OUT OF CONUS AND INTO MB BY 13Z.
FOCUS FOR AFTERNOON WILL BE HOW MUCH LOW LEVEL CLOUD CAN SCOUR
OUT AND TIMING FRONT INTO NW AND W CNTRL MN...WHICH SHOULD ARRIVE
IN FAR EASTERN ZONES NEAR PEAK HEATING. THE NAM CONTINUES TO SHOW
MUCAPES OF AROUND 1500 TO 2200 J/KG (HRRR VALUES ARE SIGNIFICANTLY
LESS) WITH BULK SHEAR AROUND 40 KTS IN THE HIGHEST CAPE AND
SLIGHTLY HIGHER BEHIND THE SFC BOUNDARY. CURRENT SPC SLIGHT RISK
AREA IS ALONG FAR EASTERN COUNTIES ALONG AND AHEAD OF
FRONT...HOWEVER NAM TIMING WOULD DRAG THE SEVERE POTENTIAL BACK
FURTHER INTO OTTER TAIL COUNTY ALONG THE SOUTHERN END OF THE
BOUNDARY. WILL MAKE LITTLE CHANGE TO PREV POPS FOR AFTN HOURS.
FRONT SHOULD EXIT CWA BY EVENING AND DRY WEATHER EXPECT FROM MID
EVENING THROUGH THE OVERNIGHT PERIOD...WITH COOL AND DRY AIR IN
THE MID 40S MOVING INTO NW ZONES.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 340 AM CDT SUN SEP 6 2015
MON NIGHT...SW FLOW ALOFT TURNING MORE ZONAL BY TUE MORNING.
A WEAK VORT MAX AND SWT ASSOCIATED WITH UPPER LOW OVER NRN
MANITOBA BRINGING A CHANCE OF WEAK SHOWERS IN THE FAR
NORTHEAST...AND WILL KEEP LOW POPS PER GOOD AGREEMENT BETWEEN
ECMWF/GFS/NAM SOLUTIONS. MAJORITY OF AREA HOWEVER WILL BE DRY
WITH MUCH COOLER AIR ENTERING FAR NW...OVERNIGHT LOWS IN THE
MID 40S AROUND LANGDON.
TUE AND TUE NIGHT...ZONAL FLOW WITH MODELS SHOWING A SFC LOW
ENTERING NORTH DAKOTA TUE NIGHT...ALTHOUGH SIGNIFICANT DIFFERENCE
ON TRACK OF LOW WITH NAM SHOWING SFC LOW OVER SRN SASK AT 12Z WED
COMPARED TO ECMWF IN CNTRL ND AND MORE BULLISH WITH SHOWERS. WILL
BRING LOW POPS INTO DVL BASIN BUT CONFIDENCE IS LOW ATTM.
WEDNESDAY THROUGH SATURDAY...MODELS GENERALLY AGREE WITH THE
OVERALL PATTERN PLACING THE REGION ON THE SOUTHERN END OF A STRONG
UPPER LOW PROPAGATING THROUGH CANADA. MOSTLY A DRY PERIOD...ALTHOUGH
ANY SHORTWAVES ROTATING THROUGH COULD LEAD TO BRIEF SHOWER CHANCES
(BEST CHANCES WED AND FRI). TEMPERATURES A BIT BELOW NORMAL
TRANSITIONING BACK TOWARD NEAR NORMAL VALUES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1255 PM CDT SUN SEP 6 2015
SURFACE TROUGH AXIS /QUASISTATIONARY FRONT/ CURRENTLY LOCATED
JUST EAST OF THE RED RIVER...AND RADAR SHOWS SOME INCREASED
THUNDERSTORM DEVELOPMENT JUST BEHIND IT NEAR KGFK AND KFAR. WILL
INCLUDE VCTS MENTION FOR THE NEXT HOUR OR SO...THEN TRANSITIONING
TO NEAR KTVF AND KBJI LATER THIS AFTERNOON. CIGS AND VIS WILL BE
ALL OVER THE PLACE AS THE THUNDERSTORMS AND THE TROUGH AXIS MOVES
THROUGH. A WEAK COLD FRONT WILL BE MOVING IN BEHIND THE TROUGH
AXIS...AND KDVL HAS ALREADY SEEN WINDS SHIFT TO THE WEST NORTHWEST
AND BECOME RATHER GUSTY. THERE ARE SOME MVFR CIGS BETWEEN THE SFC
TROUGH AXIS AND THE FRONT...BUT COVERAGE IS RATHER SPOTTY SO WILL
LEAVE OUT FOR NOW AND AMEND AS NEEDED. THE FRONT SHOULD BE NEAR
THE RED RIVER BY LATE AFTERNOON AND INTO THE EASTERN FORECAST AREA
BY EARLY EVENING. VFR CONDITIONS BEHIND THE FRONT WITH WEST WINDS
SETTLING DOWN OVERNIGHT THEN SHIFTING AROUND TO THE SOUTHWEST TO
SOUTH BY MONDAY MORNING.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...GUST
SHORT TERM...SPEICHER
LONG TERM...TG/SPEICHER
AVIATION...JR
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1240 PM CDT SUN SEP 6 2015
.DISCUSSION...SEE 18Z AVIATION DISCUSSION.
&&
.AVIATION...MAIN ISSUE WILL BE THE POTENTIAL FOR MVFR/IFR/LIFR
CONDITIONS TOWARD MORNING AT ALL BUT KCRP...WHICH IS EXPECTED TO
STAY VFR THROUGH THE PERIOD (STILL CLIMATOLOGICALLY EARLY FOR
FALL-LIKE MVFR CIGS AND EVEN LOWER VSBYS AT KCRP). WINDS NEAR THE
SURFACE AND BOUNDARY LAYER WEAKEN TONIGHT...AND WITH FOG OCCURRING
AT KVCT AND KALI THIS MORNING...COULD EXPECT SIMILAR CONDITIONS AS
THIS MORNING. ONLY FLY IN OINTMENT IS THE POSSIBLE HIGHER CLOUDS
BUT THINK THIS WILL NOT BE TOO MUCH OF A FACTOR. ALSO...ATMOSPHERE
WILL BE A TAD MOISTER SO RADIATIONAL COOLING WILL NOT BE OPTIMAL.
STILL...AM GOING WITH IFR CONDITIONS AT KVCT AND MVFR AT
KALI...WITH TEMPO LIFR FOR FOG AT BOTH TERMINALS...ALL OCCURRING
BEFORE 09Z AND 14Z. AT KLRD...COULD ONCE AGAIN HAVE THE MVFR CIGS
AS BOUNDARY LAYER BECOMES MORE SATURATED AGAIN (HAVE A TEMPO).
OTHER THAN THAT...TYPICAL DIURNAL WIND CHANGES IN THE 24 HOUR
PERIOD...WITH WINDS A BIT LOWER THIS AFTERNOON AND MONDAY WITH
SLIGHTLY WEAKER BOUNDARY LAYER WINDS BUT DIRECTIONS NOT
DRAMATICALLY DIFFERENT.
&&
.PREV DISCUSSION... /ISSUED 1040 AM CDT SUN SEP 6 2015/
DISCUSSION...ONLY REAL CHANGE IS TO REMOVE THUNDERSTORMS BUT DID
KEEP THE SLIGHT CHANCE OF RAIN IN THE FORECAST (EXTENDED IT A TAD
TO THE WEST TOO). MORNING SOUNDING HAS 12C AT 700MB SO DO NOT
THINK WE WILL SEE ANY THUNDER TODAY. HOWEVER...RADAR IS SHOWING
SOME VERY WEAK ECHOES AND HRRR MODEL/NSSL 00Z RUN WAS SHOWING SOME
VERY WEAK CONVECTION DEVELOPING DURING THE DAY. AS A RESULT...
ALTHOUGH ANY RAIN WILL LIKELY BE TRACE AMOUNTS (OR BE VERY
ISOLATED WITH COVERAGE 10 PERCENT AT BEST)...DECIDED TO KEEP THE
MENTION OF RAIN. OTHERWISE...FORECAST IS UN-DERAILED AND THUS WILL
FOREGO MAKING MODIFICATIONS AT THIS TIME WHICH MAY LIKELY NOT BE
NECESSARY ON THE AFTERNOON PACKAGE. UPDATED PRODUCTS OUT.
PREV DISCUSSION... /ISSUED 637 AM CDT SUN SEP 6 2015/
DISCUSSION...UPDATED FOR 12Z AVIATION.
AVIATION...LOW CLOUDS AND PATCHY FOG WILL CONTINUE AT THE
ALI/VCT/LRD TERMINALS FOR THE NEXT HOUR OR TWO WITH VFR CONDITIONS
RETURNING THEREAFTER. PRECIP CHANCES ARE TOO LOW TO MENTION IN THE
FORECAST TODAY...AND WILL LEAVE OUT FOR NOW. WINDS WILL PICK UP
THIS AFTERNOON WITH GUSTS AT OR SLIGHTLY ABOVE 20 KNOTS. GUSTS
SHOULD SUBSIDE AROUND 01Z. MVFR CONDITIONS MAY RETURN LATE IN THE
FORECAST AT ALI/VCT WITH PATCHY FOG AND LOW CLOUDS AGAIN DEVELOP
AND HAVE INCLUDE MVFR CONDITIONS AFTER 09Z/10Z.
PREV DISCUSSION... /ISSUED 351 AM CDT SUN SEP 6 2015/
SHORT TERM (TODAY THROUGH MONDAY)...NEAR SURFACE MOISTURE AND
LIGHT WINDS LED TO SOME FOG DEVELOPING THIS MORNING. LOCATIONS
ACROSS THE EASTERN BRUSH COUNTRY INTO THE VICTORIA CROSSROADS WILL
BE MOST LIKELY TO EXPERIENCE FOGGY CONDITIONS. VSBYS COULD BE
REDUCED OVER A SHORT DISTANCE AND FALL TO A LESS THAN A MILE AT
TIMES. CONFIDENCE IS NOT HIGH ENOUGH FOR AN ADVISORY AT THIS TIME.
UPPER LEVEL RIDGE WILL REMAIN OVER THE REGION TODAY...WHICH SHOULD
KEEP MOST PLACES DRY. THE EXCEPTION COULD BE OVER THE GULF WATERS
INTO NORTHERN COASTAL BEND WHERE SOME ISOLATED SHOWERS/STORMS
COULD DEVELOP. HAVE INCLUDED A 10 POP WITH MENTION OF SHRA/TSRA
OVER THESE AREA...ALTHOUGH CONFIDENCE IS NOT THAT HIGH AT ALL.
VERY WARM CONDITIONS ARE EXPECTED ACROSS SOUTH TEXAS AGAIN TODAY
WITH HIGHS BETWEEN 100 AND 103 DEGREES OUT WEST AND LOWER/MID 90S
ACROSS THE EAST/NORTHEAST. HI INDEX VALUES WILL BE ELEVATED
TODAY...MAINLY IN THE 105 TO 109 RANGE...AND WILL BE ISSUING SPS
TO ADDRESS THE HI. MODELS PROG SLIGHTLY DEEPER MOISTURE ARRIVING
FROM THE EAST ON MONDAY...WHICH COULD RESULT IN SOME ISOLATED TO
SCATTERED CONVECTION ACROSS THE GULF WATERS AND NORTHEAST ZONES.
ABOVE NORMAL TEMPERATURES WILL PERSIST INTO MONDAY ACROSS THE
AREA.
LONG TERM (MONDAY NIGHT THROUGH SATURDAY)...A TRANSITIONING PERIOD
WILL EXIST BY MID WEEK AS THE MID LEVEL RIDGE SHIFTS WEST AND A MID
LEVEL TROUGH/LOW MOVES IN FROM THE EAST INTO THE WESTERN GULF.
COOLING MID LEVEL TEMPERATURES COMBINED WITH PWATS OF 1.7-1.9 INCHES
WILL ALLOW FOR ISOLATED SHOWER AND THUNDERSTORM ACTIVITY PRIMARILY
ACROSS THE EASTERN THIRD OF THE CWA THROUGH WEDNESDAY. IN THE
MEANTIME...THE MID LEVEL TROUGH MOVING ACROSS NORTHERN CANADA WILL
PUSH THE ASSOCIATED SURFACE COLD FRONT ACROSS THE CENTRAL PLAINS.
FURTHER AIDE FROM THE NW TO SE H25 FLOW ACROSS THE EASTERN HALF OF
THE U.S. SHOULD PUSH THE FRONT FARTHER SOUTH INTO TEXAS. GFS AND
EURO CONTINUE TO DISAGREE WITH TIMING AND POSITIONING OF THE FRONT
FROM THURSDAY AND ONWARD...BUT OVERALL CONTINUE TO SHOW PWATS
INCREASING TO 2+ INCHES ACROSS SOUTH TEXAS...LEADING TO AT LEAST
SCATTERED ACTIVITY HEADING INTO THURSDAY AND THROUGH THE EARLY PART
OF THE WEEKEND. FOR TEMPERATURES EARLY IN THE WEEK...WITH OVERALL
SOUTHEAST FLOW THROUGH AT LEAST H85...TEMPERATURES SHOULD BE ABLE TO
RESIDE ON THE COOL SIDE OF GUIDANCE FOR EASTERN ZONES IN THE LOW
90S...WHILE H85 MIXING AND DRYING ACROSS THE WESTERN BRUSH COUNTRY
SHOULD CONTINUE TEMPS AROUND THE 100 DEGREE MARK. TEMPERATURES FOR
THE LATTER PART OF THE WEEK WILL RELY HEAVILY ON CLOUD COVERAGE AND
RAIN CHANCES...HOWEVER DID SHOW A COOLING TREND INTO THE 80S FOR THE
END OF THE WORK WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 96 78 95 77 94 / 10 10 10 10 20
VICTORIA 96 76 95 74 94 / 10 10 20 10 20
LAREDO 103 79 102 78 101 / 0 0 10 10 10
ALICE 99 76 98 75 96 / 10 0 10 10 10
ROCKPORT 93 80 91 80 90 / 10 10 20 10 20
COTULLA 102 77 102 76 100 / 0 0 10 10 10
KINGSVILLE 98 77 97 76 96 / 10 0 10 10 10
NAVY CORPUS 91 80 90 79 90 / 10 10 20 10 20
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
GW/86...AVIATION
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST 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 18Z TAF ISSUANCE
ISSUED AT 1222 PM CDT SUN SEP 6 2015
SCT SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TO
IMPACT THE CENTRAL AND NORTH-CENTRAL WI TAF SITES THROUGH AT LEAST
MID-AFTERNOON...AND MAYBE LONGER BASED ON THE LATEST RADAR TRENDS.
WIDESPREAD SHOWERS AND STORMS ALONG A EASTWARD MOVING COLD FRONT
WILL ARRIVE THIS EVENING AND CONTINUE THROUGH MUCH OF THE NIGHT.
CONDITIONS WILL DETERIORATE WITH THE RAINFALL...DROPPING CIGS/VSBYS
TO IFR...AND POSSIBLY LIFR OVER CENTRAL AND NORTH-CENTRAL WI.
CIGS/VSBYS WILL SLOWLY IMPROVE MONDAY MORNING AFTER APPROX 15Z OR SO.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
BEACH HAZARDS STATEMENT UNTIL 8 PM CDT THIS EVENING FOR WIZ022.
&&
$$
SHORT TERM.....MPC
LONG TERM......RDM
AVIATION.......MPC