Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/08/15
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 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...UPDATED
NWS MIAMI FL
1100 PM EDT MON SEP 7 2015
.UPDATE...
QUICK UPDATE TO REMOVE POPS OVER MOST OF MAINLAND AREAS OF SOUTH
FLORIDA TONIGHT...AS THE SHOWERS AND THUNDERSTORMS HAVE DISSIPATED
DUE TO THE LOST OF HEATING. THE ONLY EXCEPTION TO THIS IS OVER THE
THE WEST COAST METRO AREAS OF SOUTH FLORIDA WHERE A 20 PERCENT
POPS WILL REMAIN IN PLACE...DUE TO THE ONGOING ISOLATED SHOWERS
AND THUNDERSTORMS OVER THE GULF WATERS WHICH COULD WORK INTO THE
WEST COAST METRO AREAS. REST OF THE FORECAST LOOKS GOOD AT THIS
TIME AND NO OTHER CHANGES ARE PLANNED.
&&
UPDATE...54/BNB
.PREV DISCUSSION... /ISSUED 741 PM EDT MON SEP 7 2015/
UPDATE...
TOOK OUT MENTION OF THUNDER OVER THE MAINLAND FOR THE EVENING
UPDATE BUT LEFT SLIGHT MENTION FOR THE ATLANTIC AND GULF WATERS
WHERE THE WARMER WATERS KEEP THE LOW LEVELS UNSTABLE. THE MAINLAND
HAS BEEN RAIN COOLED AND STABILIZED WITH VERY LITTLE CHANCE TO
RECOVER WITH THE SUN SETTING SHORTLY. THE HRRR DOES SHOW SOME NEW
DEVELOPMENT LATE TONIGHT BUT FIND THAT HARD TO BELIEVE WITH THE
UPPER LOW RETROGRADING TO THE NORTHWEST OVERNIGHT ALONG WITH
SLIGHT WARMING ALOFT. SO SHOULD BE A TRANQUIL NIGHT OVERALL.
&&
KOB
AVIATION...CONVECTION ENDED FAIRLY EARLY ACROSS THE REGION AFTER
THE EARLY START WITH EVEN MID AND HIGH CLOUDS BREAKING UP AFTER 21Z.
MODELS SHOW A FAIRLY DRY OVERNIGHT ACROSS THE REGION WITH WDLY SCT
SHRA/TSRA OVER THE LOCAL GULF AND ATLANTIC. WON`T RULE OUT A FEW
BRUSHING THE COASTAL AREAS AT TIMES...BUT NOT ENOUGH CONFIDENCE TO
MENTION IN TAFS. COULD SEE A FEW MORE TSRA VCNTY KAPF AFTER 08/10Z.
SOUTH-SOUTHEAST FLOW CONTINUES INTO TUESDAY WITH SCT TSRA DEVELOPING
ALONG BOTH SEA BREEZES AFTER 08/15Z AND FOCUSING INLAND OF TAF SITES
AFTER 08/21Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 78 92 79 92 / 10 40 20 40
FORT LAUDERDALE 79 91 81 91 / 10 40 10 30
MIAMI 78 91 80 92 / 10 40 10 30
NAPLES 77 91 77 91 / 20 50 10 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...54/BNB
LONG TERM....21/KM
AREA FORECAST DISCUSSION
NWS MIAMI FL
741 PM EDT MON SEP 7 2015
.UPDATE...
TOOK OUT MENTION OF THUNDER OVER THE MAINLAND FOR THE EVENING
UPDATE BUT LEFT SLIGHT MENTION FOR THE ATLANTIC AND GULF WATERS
WHERE THE WARMER WATERS KEEP THE LOW LEVELS UNSTABLE. THE MAINLAND
HAS BEEN RAIN COOLED AND STABILIZED WITH VERY LITTLE CHANCE TO
RECOVER WITH THE SUN SETTING SHORTLY. THE HRRR DOES SHOW SOME NEW
DEVELOPMENT LATE TONIGHT BUT FIND THAT HARD TO BELIEVE WITH THE
UPPER LOW RETROGRADING TO THE NORTHWEST OVERNIGHT ALONG WITH
SLIGHT WARMING ALOFT. SO SHOULD BE A TRANQUIL NIGHT OVERALL.
KOB
&&
.AVIATION...CONVECTION ENDED FAIRLY EARLY ACROSS THE REGION AFTER
THE EARLY START WITH EVEN MID AND HIGH CLOUDS BREAKING UP AFTER 21Z.
MODELS SHOW A FAIRLY DRY OVERNIGHT ACROSS THE REGION WITH WDLY SCT
SHRA/TSRA OVER THE LOCAL GULF AND ATLANTIC. WON`T RULE OUT A FEW
BRUSHING THE COASTAL AREAS AT TIMES...BUT NOT ENOUGH CONFIDENCE TO
MENTION IN TAFS. COULD SEE A FEW MORE TSRA VCNTY KAPF AFTER 08/10Z.
SOUTH-SOUTHEAST FLOW CONTINUES INTO TUESDAY WITH SCT TSRA DEVELOPING
ALONG BOTH SEA BREEZES AFTER 08/15Z AND FOCUSING INLAND OF TAF SITES
AFTER 08/21Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 78 92 79 92 / 20 40 20 40
FORT LAUDERDALE 79 91 81 91 / 20 40 10 30
MIAMI 78 91 80 92 / 20 40 10 30
NAPLES 77 91 77 91 / 20 50 10 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...10/CD
LONG TERM....10/CD
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
910 PM EDT MON SEP 7 2015
.SYNOPSIS...
AN INLAND WEDGE OF HIGH PRESSURE AND A COASTAL TROUGH WILL DISSIPATE
TUESDAY AND TUESDAY NIGHT. ATLANTIC HIGH PRESSURE WILL THEN BUILD
OVER THE SOUTHEAST UNTIL A COLD FRONT APPROACHES THE REGION LATE
THIS WEEK. THE COLD FRONT WILL STALL OVER OR CLOSE TO THE AREA NEXT
WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
THE FORECAST AREA WILL REMAIN ON THE EASTERN PERIPHERY OF A UPPER
LOW SITUATED ALONG THE GULF COAST. DIFLUENCE WILL INCREASE AND
THE MODELS SHOW A NOTABLE SHORTWAVE MOVING INTO THE AREA FROM THE
SOUTH. AS THE FORCING ALOFT INCREASES...THE MODELS DEPICT A WARM
FRONT LIKE FEATURE LIFTING NORTHWARD WITH INCREASING SHOWER AND
THUNDERSTORM DEVELOPMENT ACCOMPANYING IT. THE MODEL PRECIPITATION
RESPONSE IS PRETTY CONSISTENT AMONGST THE SUITE OF MODELS AND
LENDS CONFIDENCE TO BRINGING IN INCREASING POPS FROM LATE EVENING
ON...MAINLY AT THE COAST AND AREAS SOUTH OF I-16 WHERE SURFACE
MOISTURE FLUX CONVERGENCE WILL BE THE MOST INTENSE. POPS WILL
RANGE FROM 10-20 PERCENT ACROSS THE FAR NORTHWESTERN TIER TO 60-70
PERCENT ALONG THE GEORGIA COAST AND AS FAR NORTH AS HILTON HEAD.
A MENTION OF HEAVY RAIN HAS BEEN MAINTAINED FOR MOST OF THE
GEORGIA COASTAL ZONES GIVEN THE EXPECTED EFFICIENT RAINFALL RATES
WITHIN THE VERY TROPICAL LIKE ATMOSPHERE.
LOWS WILL BE QUITE SIMILAR TO LAST NIGHT...MAINLY IN THE 70-73
DEGREE RANGE AWAY FROM THE BEACHES. ANOTHER ROUND OF STRATUS
DEVELOPMENT IS EXPECTED TONIGHT AS WELL...AND THERE COULD BE SOME
AREAS THAT SEE LIGHT FOG DEVELOPMENT.
FOR THE EARLY EVENING UPDATE...INCREASED POPS TO 70 PERCENT ALONG
THE GEORGIA COAST AND EXPANDED LIKELY POPS UP INTO HILTON HEAD AND
AS FAR WEST AS BLOOMINGDALE AND LUDOWICI BASED ON THE LATEST HIGH
RESOLUTION MODEL DATA AND KJAX RADAR TRENDS.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
THE INLAND WEDGE/COASTAL TROUGH WILL GRADUALLY WEAKEN TUESDAY.
BETWEEN AN UPPER LOW CENTERED WEST OF THE REGION AND AN UPPER RIDGE
BUILDING FROM THE SOUTHEAST...STRENGTHENING/MOIST SOUTHERLY FLOW
WILL CONVERGE/BE FORCED ALOFT BY SURFACE FEATURES OVER THE FORECAST
AREA...AND A WEAK WARM FRONT WILL ADVANCE NORTH THROUGH THE FORECAST
AREA. THIS SCENARIO SHOULD SUPPORT YET ANOTHER WET MORNING ALONG THE
COAST...ESPECIALLY ACROSS CENTRAL/SOUTHERN COASTAL COUNTIES. LIKELY
POPS ARE IN ORDER FOR THESE AREAS TUESDAY MORNING...TAPERED TO
SLIGHT CHANCE/CHANCE FARTHER NORTH/WEST. ALSO...PWATS EXCEEDING 2
INCHES WILL SUPPORT A THREAT FOR LOCALLY HEAVY RAIN. TUESDAY
AFTERNOON...PRECIPITATION COVERAGE BECOMES MORE UNCERTAIN AS THE
INLAND WEDGE/COASTAL TROUGH BECOME ILL-DEFINED...AND THE FOCUS FOR
CONVECTION SHIFTS TO THE SEA BREEZE/CONVECTIVE OUTFLOW BOUNDARIES.
CAPPED MAXIMUM AFTERNOON POPS AT AROUND 50 PERCENT...ESPECIALLY
ACROSS NORTHERN/INLAND COUNTIES...BUT LOCALLY GREATER AMOUNTS COULD
EVENTUALLY BE REQUIRED AS SHORT/NEAR TERM CONVECTIVE TRENDS COME
INTO FOCUS. CLOUDS/PRECIPITATION SHOULD LIMIT INSTABILITY...AND THE
POTENTIAL FOR SEVERE WEATHER REMAINS VERY LOW TUESDAY.
OTHERWISE...HIGH TEMPERATURES IN THE MID/UPPER 80S APPEAR
REASONABLE...HIGHEST SOUTH WHERE PRECIPITATION COVERAGE COULD WANE
DURING THE TIME OF MAX HEATING...ALTHOUGH TEMPERATURES COULD
STRUGGLE TO EXCEED TO THE LOWER 80S IF/WHERE CLOUDS/SHOWERS PERSIST.
TUESDAY NIGHT...POPS OVER LAND SHOULD DIMINISH..AND THE FOCUS FOR
ISOLATED/SCATTERED SHOWERS/THUNDERSTORMS SHOULD SHIFT TO COASTAL
COUNTIES ADJACENT COASTAL WATERS WHERE LOW LEVEL MASS/MOISTURE
CONVERGENCE IS EXPECTED TO DEVELOP. LOW WILL RANGE FROM THE
LOWER/MID 70S INLAND TO THE MID/UPPER 70S AT THE COAST.
WEDNESDAY...HIGH PRESSURE WILL BUILD INTO THE REGION AT THE SURFACE
AND ALOFT. SOUTH/SOUTHWEST FLOW ALOFT BETWEEN THE TROUGH TO THE WEST
AND HIGH PRESSURE CENTERED TO THE EAST/NORTHEAST WILL MAINTAIN A
FLOW OF TROPICAL MOISTURE FEATURING PWATS AROUND 2 INCHES ACROSS THE
REGION. THUS...AT LEAST CHANCE POPS FOR SCATTERED SHOWERS/
THUNDERSTORMS ARE IN ORDER ACROSS THE REGION...ESPECIALLY DURING THE
AFTERNOON AS THE SEA BREEZE ADVANCES INLAND. WHILE ELEVATED PWATS
WILL CONTINUE TO SUPPORT A LOCALIZED THREAT FOR HEAVY
RAIN...STRONGER INSTABILITY AS COMPARED WITH THE PAST FEW DAYS AND 0-
6 KM BULK SHEAR INCREASING TO 15-25 KT SUGGESTS SOME POTENTIAL FOR
MULTICELL CLUSTERS OF THUNDERSTORMS ACCOMPANIED BY A LOW CHANCE FOR
PULSE SEVERE THUNDERSTORMS WITH DAMAGING WIND GUSTS WEDNESDAY
AFTERNOON. MEANWHILE...OUTSIDE ANY THUNDERSTORMS HIGH TEMPERATURES
IN THE UPPER 80S/LOWER 90S SHOULD BECOME COMMON AWAY FROM THE COAST.
WEDNESDAY NIGHT...THE FOCUS FOR ISOLATED/SCATTERED SHOWERS/
THUNDERSTORMS SHOULD ONCE AGAIN SHIFT FROM INLAND COUNTIES TO
COASTAL COUNTIES/ADJACENT COASTAL WATERS. DUE TO UNCERTAINTY
REGARDING THE COVERAGE/IMPACTS OF WEDNESDAY AFTERNOON THUNDERSTORMS
FORECAST LOW TEMPERATURES AGAIN RANGE FROM THE LOWER/MID 70S INLAND
TO THE MID/UPPER 70S AT THE COAST. HOWEVER...A TIGHTENING PRESSURE
GRADIENT AND PERSISTENT WEST/SOUTHWEST WINDS AHEAD OF DEVELOPING PRE-
FRONTAL TROUGH NORTH OF THE REGION COULD HOLD TEMPERATURES IN THE
75-80F RANGE AT LOCATIONS WHERE NO RAIN OCCURS.
THURSDAY...07/12Z MODEL TRENDS SUGGESTS THAT THE REGION WILL REMAIN
POSITIONED BETWEEN ATLANTIC HIGH PRESSURE AND A LEE SIDE TROUGH
NORTH/WEST OF THE FORECAST AREA. THE RESULTING WEST/SOUTHWEST WINDS
AND COMPRESSIONAL HEATING SHOULD SUPPORT ABOVE NORMAL HIGH
TEMPERATURES AT LEAST IN THE LOWER/MID 90S...AND 90F TEMPS COULD
EVEN BE PUSHED TO THE COAST BEFORE THE SEA BREEZE DEVELOPS. MAX HEAT
INDEX VALUES IN THE UPPER 90S/LOWER 100S COULD BE REALIZED THURSDAY
AFTERNOON. ALSO...ISOLATED/SCATTERED THUNDERSTORMS COULD DEVELOP
NEAR THE SEA BREEZE WHICH WILL STRUGGLE TO PUSH INLAND...AND
CLUSTERS OF CONVECTION UPSTREAM COULD PUSH INTO THE REGION
ESPECIALLY INLAND COUNTIES ESPECIALLY LATE. HOWEVER...A SUBTLE
DRYING TREND COULD TRANSLATE TO FEW/NO DIURNAL SHOWERS/
THUNDERSTORMS. MAINTAINED CHANCE POPS INLAND AND SLIGHT CHANCE POPS
ELSEWHERE...ESPECIALLY THURSDAY AFTERNOON...BUT COVERAGE OF
CONVECTION COULD REMAIN SPARSE THURSDAY PM.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
A FAIRLY PROGRESSIVE UPPER PATTERN LATE WEEK THROUGH THE WEEKEND
WILL PUSH A COLD FRONT INTO THE AREA LATE FRIDAY OR SATURDAY. THIS
FRONT IS EXPECTED TO STALL ACROSS SOUTHERN AREAS THROUGH THE
WEEKEND. THE PRIMARY IMPACT WILL BE A SLIGHT INCREASE IN SHOWER AND
TSTM COVERAGE ESPECIALLY ACROSS THE COASTAL WATERS AND SOUTHEAST GA
THOUGH ALL AREAS WILL SEE SOME CONVECTION. DECREASING THICKNESSES
AND GREATER SKY COVER WILL MAINTAIN HIGH TEMPS IN THE UPPER 80S.
&&
.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
KCHS...VFR FOR MUCH OF THE PERIOD. MODELS SUGGEST ANY LOW CLOUDS
SHOULD REMAIN WEST OF THE TERMINAL AS THE LOW-LEVEL FLOW VEERS
SOUTHEAST WITH TIME. THERE ARE SIGNALS THAT A BAND OF RAIN COULD
APPROACH THE TERMINAL FROM THE SOUTH BY 14-16Z TUESDAY...BUT
CONFIDENCE IN THIS SCENARIO PANNING OUT THIS FAR OUT IS TOO LOW
TO JUSTIFY A MENTION ATTM.
KSAV...VFR THIS EVENING WITH INCREASING PROBABILITIES FOR MVFR
CIGS/VSBYS AFTER 06Z. MODELS ARE SIMILAR IN SHOWING A LARGE AREA
OF RAIN DEVELOPING ALONG THE NORTHEAST FLORIDA AND FAR SOUTHERN
GEORGIA COAST LATER THIS EVENING...THEN TREKKING NORTH AND
POTENTIALLY IMPACTING THE TERMINAL ROUGHLY 08-11Z. GIVEN THE
SIMILARITIES NOTED IN BOTH THE H3R AND RAP MODELS...WILL GO AHEAD
AND INTRODUCE A TEMPO GROUP DURING THIS TIME FOR 4SM -RA. EXPECT
PREVAILING MVFR CIGS TO DEVELOP BY 07Z AHEAD OF THE RAIN WHICH
WILL LINGER INTO MID-MORNING TUESDAY BEFORE BREAKING OUT. THE
LATEST DATA SUGGEST CIGS WILL REMAIN ABOVE IFR THRESHOLDS...BUT
VSBYS COULD BRIEFLY DROP TO IFR THRESHOLDS IN POCKETS OF HEAVIER
RAINFALL. WILL NO INCLUDE ANY IFR CONDITIONS ATTM.
EXTENDED AVIATION OUTLOOK...OUTSIDE ANY SHOWERS/THUNDERSTORMS VFR
WILL PREVAIL MUCH OF THE TIME.
&&
.MARINE...
TONIGHT...THE PERSISTENT COASTAL TROUGH IS EXPECTED TO BE ALIGNED
RIGHT AT THE COAST THIS EVENING AND THEN GRADUALLY DISSIPATE OR
SHIFT ONSHORE THROUGH THE NIGHT. THE PREVAILING FLOW WILL BE MORE
EASTERLY AND EVENTUALLY SOUTHEASTERLY AS THE NIGHT PROGRESSES. THE
PRESSURE GRADIENT WILL NOT BE AS TIGHT AND WIND SPEEDS ARE EXPECTED
TO TOP OUT IN THE 10-15 KT RANGE...MAINLY FOR THE GEORGIA WATERS
LATE TONIGHT. SEAS WILL BE 2-3 FT...HIGHEST BEYOND 20 NM. SHOWERS
AND STORMS ARE EXPECTED TO INCREASE FROM THE SOUTH LATE TONIGHT AND
COULD PRODUCE LOCALLY HEAVY RAINFALL...REDUCING VISIBILITIES AT
TIMES OVER THE WATERS.
THE INLAND WEDGE/COASTAL TROUGH REGIME WILL GRADUALLY YIELD TO
ATLANTIC HIGH PRESSURE WHICH WILL EXPAND WEST TUESDAY AND WILL
PREVAIL UNTIL LATE WEEK. AS A RESULT...EAST/NORTHWEST WINDS WILL
GIVE WAY TO SOUTHEAST WINDS TUESDAY...THEN WINDS WILL VEER TOWARD
THE SOUTH/SOUTHWEST TUESDAY NIGHT THROUGH FRIDAY. THROUGH
MIDWEEK...WINDS MAINLY 10-15 KT AND SEAS 1-3 FT WILL PREVAIL.
THEN...AHEAD OF AN APPROACHING COLD FRONT THE GRADIENT WILL
TIGHTEN...AND WINDS WILL INCREASE TO 15-20 KT AND SEAS WILL BUILD TO
2-4 FT. WHILE THE PROBABILITY FOR SMALL CRAFT ADVISORY CONDITIONS
WILL INCREASE THROUGH THE LATTER HALF OF THE WEEK...GUIDANCE
MAINTAINS WINDS LESS THAN 25 KT AND SEAS BELOW 6 FT THROUGH THE
PERIOD. THE COLD FRONT WILL ADVANCE IN THE WATERS AND WILL STALL
NEXT WEEKEND...SO WINDS/SEAS REMAIN UNCERTAIN AND WILL DEPEND ON THE
TIMING/POSITION OF THE FRONT.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
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 DES MOINES IA
957 PM CDT MON SEP 7 2015
.UPDATE...
ISSUED AT 944 PM CDT MON SEP 7 2015
AT THE PRESENT TIME I DID NOT MAKE LARGE SCALE CHANGES TO THE
GOING FORECAST HOWEVER...THE LATEST HRRR IS SUGGESTING THAT THE
HEAVY RAINFALL WOULD BE FOCUSED MORE ACROSS NORTHERN IOWA. ONGOING
STORMS ACROSS NEBRASKA/KANSAS HAS BEEN FIZZLING AS THEY CROSS INTO
IOWA. IT APPEARS THESE STORMS HAVE FIRED ALONG AN INSTABILITY AXIS
WHERE MOISTURE TRANSPORT AS BEEN PRETTY GOOD. AS A LOW LEVEL JET
DEVELOPS I STILL EXPECT STORMS TO EVENTUALLY WORK ACROSS SOUTHERN
IOWA OVERNIGHT AND GIVEN THE HEAVY RAINFALL WE RECEIVED LAST NIGHT
IT WON`T TAKE MUCH TO PRODUCE FLASH FLOODING. HOWEVER...A SURFACE WARM
FRONT IS SITUATED ACROSS NORTHERN IOWA AND THERE IS AN APPROACHING
SHORTWAVE COMING ACROSS CEN NEB/SOUTH DAKOTA WHICH SHOULD BE
MOVING INTO NORTHERN IOWA OVERNIGHT. CONVECTION HAS BEEN RATHER
ROBUST IN THIS AREA THIS EVENING. MOISTURE TRANSPORT HAS INCREASED
INTO THIS AREA AND ONCE A SW LOW LEVEL JET GETS GOING CONVECTION
SHOULD INCREASE IN THIS AREA AND OVERSPREAD NORTHERN IOWA. THE
HRRR HAS LATCHED ONTO THIS IDEA AND IT CERTAINLY APPEARS
REASONABLE TO ME. I HAVE INCREASED POPS AND QPF FOR NOW BUT WOULD
NOT BE SURPRISED TO SEE THE HEAVY RAIN AREA SHIFTED FURTHER NORTH.
WILL BE WATCHING THE EVOLUTION OF THIS WITH TIME BUT FOR NOW I`M
BECOMING INCREASINGLY CONCERNED ABOUT NORTHERN IOWA.
&&
.SHORT TERM /TONIGHT/...
ISSUED AT 327 PM CDT MON SEP 7 2015
HEAVY RAIN REMAINS THE CONCERN OF THE OVERNIGHT FORECAST.
OVERNIGHT CONVECTION HAS LAID OUT AN OUTFLOW BOUNDARY OVER
NORTHERN MISSOURI WHICH IS TIED BACK INTO THE LOW OVER KANSAS.
THE SYNOPTIC BOUNDARY IS STILL OVER IOWA...STRETCHING FROM NEAR
PRAIRIE DU CHIEN BACK WEST TO NEAR DENISON. H850 FRONT IS ALSO
SITUATED OVER IOWA NOW. THE MODELS ARE HAVING DIFFICULTY WITH THE
EVOLUTION OF THE CONVECTION TONIGHT...BUT AN OVERALL CONSENSUS IS
FOR THE CENTRAL AND SOUTH TO RECEIVE THE BALANCE OF THE FORCING
AND THUS...RAINFALL. THE NAM WAS FARTHER SOUTH WITH THE MAIN QPF
AXIS TONIGHT...WHILE THE GFS LOOKS VERY SIMILAR TO LAST NIGHTS
FARTHER NORTH PLACEMENT OVER IOWA...THIS TIME RIGHT OVER THE I80
CORRIDOR. THE OTHER MESO MODELS SHOW A VARIETY OF SOLUTIONS...WITH
THE HIRES ARW HAVING A FOCUS FOR TWO AREAS OF HEAVY RAINFALL...ONE
NEARER THE IA/MO BORDER AND ONE ALONG THE I80 CORRIDOR. THE LATEST
HRRR RUN IS SHOWING TWO MAXIMA AS WELL...WITH A LESS ORGANIZED
CLUSTERING THAN THE OTHER MODELS MENTIONED. A NUMBER OF FACTORS
ARE POINTING TOWARD TWO MAXIMA...ONE THE H850 BOUNDARY IS ALREADY
BECOMING ACTIVE OVER CENTRAL NEBRASKA AND THERE IS ALSO SOME
DEVELOPMENT ALONG THE TRIPLE POINT IN SOUTHEAST NEBRASKA NEARER
THE SFC LOW...COOL FRONT...AND OUTFLOW BOUNDARY INTERSECTION. THE
SOUTHERN CLUSTER WILL FOLLOW THE BOUNDARY UNTIL IT IS LIFTED NORTH
THIS EVENING...WHILE THE NORTHERN AREA WILL CONTINUE TO FILL IN
THROUGH THE EVENING HOURS. AS THE LOW LEVEL JET KICKS IN BETWEEN
02-03Z THIS EVENING...THE COVERAGE AND INTENSITY OF THE CONVECTION
SHOULD INCREASE. NOTHING MUCH HAS CHANGED WITH REGARD TO THE
AVAILABLE MOISTURE...STILL RUNNING ABOUT 2.30 INCH PWATS AT 06Z
OVER THE SOUTH THIRD WITH WARM CLOUD DEPTHS PUSHING 13.8 KFT AT
OVERNIGHT. THE SCENARIO IS PRETTY MUCH THE SAME FOR EFFICIENT
RAINFALL PROCESSES TONIGHT...SO HAVE GENERALLY GONE ABOUT 1 TO 2
INCHES ACROSS THE SOUTH WITH THE EXPECTATION THAT THERE MAY BE
SOME TOTALS IN THE 4 TO 5 INCH RANGE BY MORNING. AS THE LOW
PUNCHES NORTH THIS EVENING...LOWS WILL REMAIN WARM SOUTH/SOUTHEAST
WITH SLIGHTLY COOLER NORTHWEST. SHOWERS WILL HOLD ON IN THE
SOUTHEAST. WITH LIGHT WINDS IN THE MORNING...PATCHY TO AREAS OF
FOG MAY ALSO DEVELOP.
.LONG TERM /TUESDAY THROUGH MONDAY/...
ISSUED AT 327 PM CDT MON SEP 7 2015
THE LONG TERM FORECAST GROWS GENERALLY MORE AUTUMNAL AS A SERIES
OF NORTHERN STREAM MID/UPPER LEVEL TROUGHS ROUNDING BROAD CYCLONIC
FLOW KEEP THE MORE SUMMERLIKE WEATHER BENEATH A LARGE RIDGE
SHUNTED OFF TO OUR SOUTH AND WEST. THE FIRST OF THESE TROUGHS WILL
MOVE OVERHEAD ON TUESDAY...POSSIBLY GENERATING SOME ELEVATED
SHOWERS AND THUNDERSTORMS MAINLY ACROSS THE SOUTHERN HALF OF THE
FORECAST AREA. HOWEVER...THE SURFACE FRONT SHOULD BE BLOWN THROUGH
INTO MISSOURI BY TONIGHTS CONVECTION AND ANY SEVERE WEATHER OR
HEAVY RAIN THREAT WILL BE SOMEWHAT DIMINISHED TOMORROW. THIS
INITIAL TROUGH WILL ALSO FINALLY SCOUR OUT OUR WARM AND JUICY
AIRMASS OUT OF IOWA...WITH A COOL AREA OF HIGH PRESSURE BRINGING
DRY AND PLEASANT WEATHER BY WEDNESDAY.
THE SECOND...SUBSTANTIALLY STRONGER MID/UPPER LEVEL TROUGH WILL
DEEPEN AS IT MOVES OVER MINNESOTA AND WISCONSIN AROUND THURSDAY
NIGHT AND FRIDAY. THIS WILL PUSH A MORE PRONOUNCED REINFORCING
COLD FRONT ACROSS IOWA DURING THIS TIME FRAME...BRINGING
CONSIDERABLY COOLER WEATHER FROM FRIDAY INTO SATURDAY. THE PASSAGE
OF THE FRONT WILL LIKELY GENERATE ISOLATED TO SCATTERED SHOWERS
AND THUNDERSTORMS AROUND THURSDAY NIGHT...BUT TIMING DIFFERENCES
AMONG THE MODELS PROHIBIT GOING HIGHER THAN 20 OR 30 POPS AT THIS
TIME. WHILE THE FORCING AND WIND FIELDS ASSOCIATED WITH THE
PASSAGE OF THIS SYSTEM MAY BE ROBUST...INSTABILITY SHOULD BE
LIMITED MITIGATING ANY SEVERE WEATHER THREAT. THE ALTERNATING
PATTERN OF TROUGHS AND RIDGES WILL CONTINUE FROM THE WEEKEND INTO
NEXT WEEK WITH SUNSHINE AND RECOVERING TEMPERATURES ON SUNDAY
FOLLOWED BY ANOTHER COLD FRONT ON MONDAY OR MONDAY NIGHT...AND
POSSIBLY ANOTHER AROUND WEDNESDAY OR THURSDAY OF NEXT WEEK THOUGH
THAT IS BEYOND THE SEVEN DAY FORECAST PERIOD.
OUTSIDE OF SOME LINGERING POTENTIAL FOR STRONG STORMS OR HEAVY
RAIN ON TUESDAY...WHICH SHOULD BE AN ISOLATED THREAT...AND THE
LOW POSSIBILITY OF PERHAPS A COUPLE OF BRIEFLY STRONG STORMS WITH
THE FRONT AROUND THURSDAY NIGHT...THERE IS LITTLE IN THE WAY OF
HAZARDOUS OR HEADLINE INDUCING WEATHER DURING THE NEXT SEVEN DAYS.
OVERALL IT WILL BE COOLER...DRY...AND STARTING TO FEEL LIKE FALL
ACROSS IOWA.
&&
.AVIATION...08/00Z
ISSUED AT 723 PM CDT MON SEP 7 2015
MVFR/LCL IFR CIG MOVING INTO THE FORECAST AREA AND WILL LIKELY
AFFECT SOUTHERN TAF LOCATIONS CLOSER TO 05Z. SHOWERS/STORMS
BREAKING OUT OVER ERN NEB IN A MOIST AND UNSTABLE AIRMASS BUT THE
MAIN TRIGGER WILL BE A SHORT WAVE OVR WESTERN NEB THAT WILL INTERACT
WITH A BOUNDARY AND HEAVY RAIN PRODUCING STORMS WILL RESULT MOVING
ACROSS THE SOUTHERN HALF OF THE STATE AF 05Z THROUGH ABOUT 12Z. FOG
WILL ALSO DEVELOP ACROSS TAF LOCATIONS REDUCING VSBY AND CIGS AFT
09Z. THERE WILL BE IMPROVEMENT FROM NW TO SE AFT 15Z.
&&
.HYDROLOGY...
ISSUED AT 327 PM CDT MON SEP 7 2015
EVEN WITH THE RESPITE IN RAIN TODAY...WE STILL REMAIN PRIMED FOR
ADDITIONAL RISES IN RIVERS OVER THE NEXT SEVERAL DAYS.
LAST NIGHTS EXTREME RAINS WERE FAIRLY LOCALIZED IN THE RACCOON RIVER
BASIN AND WITH ADDITIONAL RAINFALL TONIGHT...SOME LOCATIONS MAY
REACH MODERATE CATEGORY ACROSS CENTRAL IOWA. CONFIDENCE ON TONIGHTS
RAINFALL IS SOMEWHAT LIMITED DUE TO LAST NIGHTS CONVECTION AND THE
EXPECTED RECOVERY OF STORMS LATER TONIGHT FARTHER WEST IN NEBRASKA.
IF THE STORMS FOLLOW A SIMILAR EVOLUTION TO LAST NIGHT...THE RACCOON
RIVER WOULD BE FURTHER AFFECTED...ALONG WITH SOME IMPACTS FOR
STREAMS AND CREEKS OVER CENTRAL AND SOUTHERN IOWA...LEADING TO
LOCALIZED FLASH FLOODING OVERNIGHT AND ADDITIONAL RISES TO MAIN STEM
RIVERS AND POSSIBLE RIVER FLOOD WARNINGS IN THE NEXT FEW DAYS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 7 AM CDT TUESDAY FOR ADAIR-ADAMS-
APPANOOSE-AUDUBON-BOONE-CARROLL-CASS-CLARKE-CRAWFORD-DALLAS-
DAVIS-DECATUR-GREENE-GUTHRIE-JASPER-LUCAS-MADISON-MAHASKA-MARION-
MARSHALL-MONROE-POLK-POWESHIEK-RINGGOLD-STORY-TAMA-TAYLOR-UNION-
WAPELLO-WARREN-WAYNE.
&&
$$
UPDATE...FAB
SHORT TERM...REV
LONG TERM...LEE
AVIATION...FAB
HYDROLOGY...REV
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
646 PM CDT MON SEP 7 2015
...Update to near term convective forecast and aviation forecast
discussion...
.UPDATE...
ISSUED AT 636 PM CDT MON SEP 7 2015
The environment across the forecast area continues to evolve this
evening, and have adjusted the severe thunderstorm watch
accordingly. First off, northeast Kansas appears to have
stabilized substantially, and while there is a westerly advection
component of the more unstable central KS air, limited daytime
heating should keep the severe potential quite low in northeast
KS. Should note that ample shear remains in place, so any elevated
storms that can recognized this shear would pose a short lived
severe threat.
Central and east central KS remain quite unstable, with perhaps
the greatest instability into east central Kansas where Emporia
has a temperature of 88 with a dewpoint of 73 at last hour, likely
resulting in surface based CAPE well over 2000 J/Kg. Meanwhile,
effective shear at or greater than 40 kts has overspread the area.
This has fueled recent supercell development in Marion county and
could sustain the severe threat across the rest of east central KS
as well...although again the instability decreases into far
eastern KS. An outflow boundary near/just north of Emporia may
serve as a focus for severe storm development with very large
hail, damaging winds, and a small but non-zero threat for
tornadoes. Severe threat should wane after 9 PM.
&&
.SHORT TERM...(THIS EVENING THROUGH Tuesday)
ISSUED AT 402 PM CDT MON SEP 7 2015
Showers and isolated storms continued off and on through the
afternoon hours in a zone of 1000-900mb convergence, weak isentropic
lift and the presence of a weak wave. Although the bulk of the
precipitation has moved east into missouri expect isolated to
scattered showers to continue across east central Kansas into the
early evening hours. Further north near the Nebraska border where
few clouds have allowed temperatures to warm into the lower to mid
90s. Latest mesoanalysis shows about 40 to 50kts of effective
shear, 1500-3000 J/kg of CAPE and no cap in place. Isolated
thunderstorms have developed just to the northwest of the forecast
area and were moving northeast across southern Nebraska at 1930Z.
Latest runs of the HRRR and the RAP suggest further development
across north central Kansas into the evening hours, with
additional development from central Kansas across northeast Kansas
through the evening hours. Storms that can develop across the
northern counties may be severe with hail, strong winds and an
isolated tornado possible. Another round of storms is expected
overnight into Tuesday morning as the upper level trough
progresses eastward across the Northern and Central Plains. Good
moisture transport is expected into northeast Kansas overnight
with precipitable water around 2 inches which will increase the
potential for locally heavy rainfall. The front is expected to
move slowly southeast across the forecast area on Tuesday then
moving out of east central Kansas Tuesday evening. Showers and
thunderstorms will likely be ongoing in the morning hours and then
continue along the boundary in the afternoon.
Clouds south of I-70 have kept temperatures in check in the upper
70s to upper 80s. Will likely still see some fluctuations in
temperatures through the late afternoon where the sun can come out.
Tonight, lows should cool into the low to mid 70s with highs on
Tuesday only in the low to mid 80s.
.LONG TERM...(Tuesday NIGHT THROUGH Monday)
ISSUED AT 402 PM CDT MON SEP 7 2015
Cold front and associated showers and thunderstorms should be
moving to the southeast out of east central KS Tuesday evening.
Then surface high pressure builds in with pleasant temperatures
and lower humidities for Wednesday and Wednesday night.
Northwest flow aloft then sets up through the end of the week
with the first in a series of disturbances possibly affecting
north central KS by late Thursday afternoon. That system moves
through Thursday night through Friday with a good chance of
thunderstorms during this time.
Subsidence behind the trough and associated surface high pressure
builds in for Saturday, and an upper ridge builds eastward for
Sunday and Monday, keeping the weekend into Monday dry.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z Tuesday EVENING)
ISSUED AT 636 PM CDT MON SEP 7 2015
Main TAF focus is on convection as the next 18 to 24 hours could
feature scattered thunderstorms in and near TAF sites at any given
time. The best chances appear to be over the next few hours and
have run prevailing VCTS group with TEMPO periods of IFR vis owing
to the scattered nature of the heavy rain. Beyond 05Z, have
maintained a VCTS group, but more for uncertainty rather than a
persistent TS in the vicinity of the aerodromes. Winds should turn
more out of the northeast by tomorrow afternoon with lower but
non-zero TS chances.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Barjenbruch
SHORT TERM...53
LONG TERM...GDP
AVIATION...Barjenbruch
AREA FORECAST DISCUSSION
NWS GOODLAND KS
535 PM MDT MON SEP 7 2015
.UPDATE...
ISSUED AT 526 PM MDT MON SEP 7 2015
WITH MAIN AREA OF THUNDERSTORMS AHEAD OF FRONTAL ZONE TO THE SOUTH
OF THE AREA AND ATTEMPTS AT CONVECTION FADING ACROSS EXTREME
SOUTHWEST CWA HAVE REFINED POPS AND WX TO MORE CLOSELY FOLLOW
DEVELOPING LINE OF CONVECTION ACROSS NORTHEAST COLORADO ALONG
ROBUST COLD POOL. STARTING TO SEE SIGNIFICANT WIND GUSTS TO AROUND
45 MPH WITH THIS FEATURE AND THINK THAT WILL CONTINUE FOR NEXT 2
HOURS. WITH STRONGER CAP ACROSS THE EASTERN CWA NOT SURE HOW FAR
LINE WILL MAKE IT...SO HAVE BEEN SOMEWHAT PESSIMISTIC ABOUT
CHANCES ACROSS EASTERN HALF OF AREA.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH TUESDAY)
ISSUED AT 143 PM MDT MON SEP 7 2015
EARLY AFTERNOON WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOWS SW
FLOW IN PLACE ACROSS CENTRAL ROCKIES OVER OUR CWA...AND INTO THE
NORTHERN PLAINS. THIS IS AHEAD OF LARGE UPPER LOW CENTERED OVER
CENTRAL CANADA WITH BROAD TROUGHING EXTENDING SOUTH ACROSS THE
PACIFIC NORTHWEST. CHECKING DYNAMIC TROPOPAUSE...EMBEDDED WEAK
SHORTWAVE TROUGH THAT ROTATED THROUGH REGION THIS MORNING IS NOW
OVER NORTHCENTRAL KS WITH A STRONGER PV HEIGHT ANOMALY ENTERING
CENTRAL COLORADO. SUBSIDENCE BEHIND THE INITIAL FEATURE IS STILL
TRANSITIONING ACROSS MOSTLY OF OUR CWA. AT THE SURFACE A STALLED
FRONT IS JUST SOUTH OF INTERSTATE 70 WITH SURFACE LOW EXTENDING
FROM SOUTHERN COLORADO ACROSS SW KS AND INTO NW KANSAS.
THIS AFTERNOON-TUESDAY...FORCING IS EXPECTED TO INCREASE THIS
EVENING WITH NEXT SHORTWAVE TROUGH MOVING OUT OF THE CENTRAL ROCKIES
AND INTERACTING WITH STALLED FRONTAL ZONE OVER OUR CWA. THERE IS
THE POSSIBILITY FOR OVERRUNNING/BACKBUILDING ALONG ELEVATED FRONTAL
ZONE/STRENGTHENING H7 TROUGH AXIS AS THIS FEATURE MOVES ACROSS THE
REGION. EAST/NORTHEAST FLOW WILL CONTINUE TO ADVECTS BOUNTIFUL
MOISTURE OVER OUR CWA...WITH MODERATE INSTABILITY CONTINUING
THROUGH THE EVENING. CONFIDENCE IS LOWER REGARDING COVERAGE...WITH
FAIRLY LARGE SPREAD IN GUIDANCE SINCE OVERNIGHT AND SUBSIDENCE
INITIALLY IN PLACE OVER OUR CWA. CURRENT ARW/NMM DEPICTS ACTIVITY
INITIATING WEST OF OUR CWA...OR OVER OUR WESTERN CWA AROUND 00Z AND
TRACKING ALONG/NORTH OF FRONT THIS EVENING/OVERNIGHT BEFORE SLOWLY
TRANSITIONING EAST. HRRR/RAP BOTH SUPPORT A SIMILAR LOCATION AND
TIMING...HOWEVER SHOW MUCH LESS IN THE WAY OF COVERAGE. I FELT
COMFORTABLE ADJUSTING THE TIMING TO FAVOR THIS EVENING FOR BEST
COVERAGE AND KEPT MENTION LIMITED TO CHANCE FOR NOW. GUIDANCE SHOWS
BAROCLINIC ZONE LINGERING THROUGH EARLY AFTERNOON TUESDAY ACROSS OUR
SOUTHEAST WITH ADDITIONAL SHOWER/THUNDERSTORM DEVELOPMENT POSSIBLE.
I SHOWED GRADUAL TRANSITION TO THE EAST/SOUTHEAST IN LINE WITH
MODEL CONSENSUS.
REGARDING SEVERE THREAT...HIGH LOW LEVEL MIXING RATIOS HAVE AIDED IN
MODERATE INSTABILITY BUILDING ACROSS OUR CWA WITH ML CAPE 1500-2500
J/KG DEPICTED ON RAP ANALYSIS. DEEP UNIDIRECTIONAL FLOW HAS LED TO
HIGH SHEAR IN MID TO UPPER LEVELS WITH EFFECTIVE SHEER VALUES
ALREADY IN EXCESS OF 50KT OVER OUR CWA. BEST LOW LEVEL SHEAR IS
OVER NORTH CENTRAL KS/NEAR HILL CITY ASSOCIATED WITH VEERING NEAR
WHERE CLOSED SURFACE LOW MAY BE DEVELOPING BASED ON WIND/PRESSURE
FIELD. SEVERE THREAT SHOULD PREDOMINANTLY BE CONFINED TO LARGE
HAIL/DAMAGING WINDS...HOWEVER LOCATIONS IN THE FAR EASTERN PART OF
OUR CWA COULD SEE FAVORABLE CONDITIONS FOR SUPERCELL DEVELOPMENT
AND TORNADO RISK. WINDOW FOR THIS SHOULD BE CONFINED TO THIS
AFTERNOON/EARLY EVENING WITH FRONT TRANSITIONING BACK TO THE
SOUTHEAST THIS EVENING.
RAP/HRRR/NAM/SREF CONTINUE TO SHOW STRATUS/FOG REDEVELOPING ACROSS
NEBRASKA AND ADVECTING/SPREADING SOUTHWEST ACROSS OUR CWA. LOWEST
VIS COULD APPROACH DENSE FOG ADVISORY CRITERIA...THOUGH IT DOES
APPEAR TO BE FAIRLY TRANSIENT REGARDING LOWEST VISIBILITIES. FOR NOW
I KEPT AREAS OF FOG MENTION...AND WILL ALLOW SUBSEQUENT SHIFTS TO
MONITOR NEED FOR NEW DENSE FOG ADVISORY.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 230 PM MDT MON SEP 7 2015
THE WESTERLY FLOW ALOFT ACROSS THE CENTRAL HIGH PLAINS TURNS NORTHWESTERLY
BY THURSDAY AND MORE NORTHERLY BY FRIDAY AND SATURDAY AS THE HIGH
PRESSURE AREA ALOFT OVER NORTHERN MEXICO RETROGRADES AND MERGES
WITH THE HIGH IN THE EASTERN PACIFIC TO FORM A RIDGE OVER THE
WESTERN UNITED STATES WHILE SHORT WAVES EMBEDDED IN THE UPPER
FLOW MOVE THROUGH THE CENTRAL HIGH PLAINS AND INTO THE BASE OF THE
TROUGH DEEPENING IN THE MISSISSIPPI VALLEY REGION. EXPECT ISOLATED
TO SCATTERED SHOWERS AND THUNDERSTORMS FROM WEDNESDAY NIGHT
THROUGH FRIDAY NIGHT AS A RESULT OF THESE DISTURBANCES MOVING
ACROSS THE REGION WITH THE SURFACE FRONTAL BOUNDARY REMAINING
STALLED IN THE VICINITY OF THE FORECAST AREA THROUGH THE END OF
THE WEEK. EXPECT DAYTIME HIGHS MAINLY IN THE 80S WITH LOWS MAINLY
IN THE 50S THROUGH THIS PERIOD.
SOMEWHAT COOLER TEMPERATURES ARE EXPECTED ON FRIDAY AND SATURDAY
WITH DRY CONDITIONS SATURDAY AND SUNDAY IN THE WAKE OF THE
STRONGER SHORT WAVE TROUGH ALOFT AND THE HIGH PRESSURE AREA TO
FOLLOW A COLD FRONT ACROSS THE REGION. SURFACE HIGH PRESSURE MOVES
OUT OF THE FORECAST ARE ON SUNDAY WITH THE LEE TROUGH DEVELOPING
AND TEMPERATURES WARMING AGAIN WITH SOUTHWEST SURFACE FLOW AND THE
WEAKENING RIDGE ALOFT OVER SOUTHWEST U.S. EXTENDING INTO THE
CENTRAL HIGH PLAINS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 526 PM MDT MON SEP 7 2015
MVFR CONDITIONS CONTINUE AT MCK ALTHOUGH OVERALL STRATUS DECK
CONTINUES TO SHRINK. MAY SEE SOME VARIATIONS BETWEEN BKN AND FEW
FOR A FEW HOURS BEFORE THINGS FINALLY CLEAR. ALTHOUGH THREAT FOR
THUNDERSTORMS PRESENT TONIGHT...MAIN CONCERN WILL BE POTENTIAL FOR
VERY HUMID AIR BACKING INTO AREA OVERNIGHT BRINGING ANOTHER ROUND
OF AT LEAST LOW CIGS. WHILE QUITE A BIT OF UNCERTAINTY
REMAINS...MAINLY DUE TO UNSURE EVOLUTION OF THUNDERSTORMS HAVE
KEPT CIGS IN THE IFR RANGE AFTER 10Z AT MCK AS PATTERN REMAINS
FAVORABLE FOR ANOTHER PERIOD OF STRATUS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JRM
SHORT TERM...DR
LONG TERM...LOCKHART
AVIATION...JRM
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 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 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 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
NWS GLASGOW MT
754 PM MDT MON SEP 7 2015
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH WEDNESDAY...
A LOBE OF UPPER ENERGY IS EXPECTED TO SWING THROUGH THE AREA
TONIGHT ON THE BACKSIDE OF AN AREA OF LOW PRESSURE CENTERED OVER
CENTRAL CANADA. THE GFS AND HRRR MODELS DEPICT ISOLATED SPRINKLES
OR LIGHT SHOWERS TO MAINLY AFFECT THE NORTHERN BORDER AREAS AND
WITH SCATTERED SHOWERS CURRENTLY OCCURRING OVER ALBERTA/WESTERN
SASK...INCREASED POPS/WX FOR ISOLATED/SLIGHT CHANCE WORDING. REST
OF FORECAST LOOKED TO BE IN DECENT SHAPE. TFJ
PREVIOUS DISCUSSION...
A FEW LIGHT SHOWERS/SPRINKLES SHOWING UP IN THE UNSTABLE CYCLONIC
FLOW AROUND THE LARGE LOW OVER CENTRAL CANADA. EXPECT THESE
SHOWERS TO WEAKEN AS THE CUMULUS FIELD DISSIPATED DURING THE
EVENING.
WAVE SLIDING INTO SOUTHWEST MONTANA COULD PRODUCE A FEW SHOWERS
OVER SOUTHERN MONTANA OVERNIGHT THAT MAY REACH AS FAR NORTH AS THE
SOUTHERN ZONES.
A WEAK AND DRY FRONTAL SYSTEM CROSSES THE STATE ON TUESDAY. SOME
GUSTY WINDS POSSIBLE WITH WEAK COLD AIR ADVECTION IN THE AFTERNOON
BUT THE OVERALL IMPACT FROM THIS SYSTEM WILL BE SMALL. NORTHWEST
FLOW CONTINUES ON WEDNESDAY AS ANOTHER HIGH PRESSURE DROPS OUT OF
CANADA. EBERT
.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...
LITTLE CHANGE WAS MADE TO PREVIOUS THINKING WITH 12Z MODEL
GUIDANCE SHOWING ONLY SMALL RUN TO RUN VARIATION FROM OOZ. THERE
IS SOME QUESTION AS TO WHETHER WEAK EMBEDDED SHORTWAVES IN THE
UPPER FLOW MAY PROVIDE ISOLATED SHOWERS SOMETIME ABOUT THURSDAY OR
FRIDAY...BUT TIMING DIFFERENCES EXIST IN THE GFS/ECMWF. WILL HOLD
OFF FOR NOW. NEXT SYSTEM OF SIGNIFICANTS LOOKS TO APPROACH BY
ABOUT THE END OF THE LONG TERM PERIOD WITH A CHANCE FOR SHOWERS
AND MAYBE SOME THUNDER AS WELL. MALIAWCO
PREVIOUS DISCUSSION...
NORTHEAST MONTANA WILL REMAIN IN NORTHWEST FLOW ALOFT THURSDAY
AND FRIDAY WITH AN UPPER RIDGE TO THE WEST AND AN UPPER TROUGH/LOW
TO THE EAST.
WEAK SHORTWAVES ARE EXPECTED TO MOVE THROUGH NORTHEAST MONTANA
WEDNESDAY NIGHT AND THURSDAY NIGHT. FOR WEDNESDAY NIGHT...ECMWF
DOES WANT TO BRING SOME MOISTURE WHILE THE GFS REMAINS DRY.
EARLIER MODEL RUNS WERE DRY WITH THIS WAVE. WILL MAINTAIN DRY
FORECAST FOR NOW. THURSDAY NIGHT`S WAVE REMAINS DRY AT THIS TIME.
AN UPPER RIDGE WILL MOVE INLAND FOR SATURDAY WITH DRY WEATHER AND
SOMEWHAT WARMER TEMPERATURES. AN UPPER TROUGH DROPS SOUTH INTO THE
AREA SUNDAY AND MONDAY WITH A COLD FRONT AND A CHANCE OF SHOWERS.
FORRESTER
&&
.AVIATION...
VFR CIGS AND VSBYS WILL CONTINUE INTO TONIGHT. EXPECT NEAR CALM
WINDS OVERNIGHT AND BREEZY WINDS DURING THE AFTERNOON HOURS. A
STRAY SPRINKLE MAY BE POSSIBLE...BUT CONFIDENCE IS NOT STRONG
ENOUGH TO INCLUDE IN A PREVAILING GROUP. MALIAWCO/MICKELSON
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
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 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
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 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...UPDATED
NWS ALBUQUERQUE NM
550 PM MDT MON SEP 7 2015
.AVIATION...
00Z TAF CYCLE
SCT TO NMRS SHOWERS AND ISOL STORMS MOSTLY ALONG AND SOUTH OF
INTERSTATE 40 THROUGH 06Z...DIMINISHING THEREAFTER. THE STRONGER
STORMS WILL PRODUCE BRIEF MODERATE TO HEAVY RAIN WITH LCL MVFR
CIGS/VSBYS AND OCCASIONAL MT OBSCURATIONS AS WELL AS WND GUSTS TO
40KT. OTHERWISE VFR CONDITIONS. TUESDAYS CROP OF SHOWERS AND
STORMS WILL BE LESS IN COVERAGE...WITH ISOL TO SCT COVERAGE
FAVORING THE SOUTH AND EAST. CHJ
&&
.PREV DISCUSSION...302 PM MDT MON SEP 7 2015...
.SYNOPSIS...
STORMS WILL CONTINUE THIS EVENING LARGELY FOR AREAS SOUTH OF
INTERSTATE 40 WHERE SPOTTY LOCATIONS MAY SEE A HALF INCH OR MORE
OF RAIN. A BACK DOOR COLD FRONT WILL SLIDE DOWN THE PLAINS
TUESDAY AND TUESDAY NIGHT BEFORE PUSHING THROUGH THE GAPS OF THE
CENTRAL MOUNTAIN CHAIN WEDNESDAY MORNING. SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE BEHIND THE FRONT ACROSS THE PLAINS.
TEMPERATURES WILL COOL IN THE WAKE OF THE FRONT...BUT WILL STILL
BE RIGHT AROUND NORMAL VALUES FOR EARLY SEPTEMBER WEDNESDAY
AFTERNOON. MID LEVEL DRY AIR WILL CONTINUE TO PUSH INTO THE STATE
ON THURSDAY AND FRIDAY...BUT ANOTHER BACK DOOR FRONT WILL BE
LURKING AS WELL.
&&
.DISCUSSION...
MOST OF THE RATHER WELL-BEHAVED STORMS TODAY HAVE STAYED SOUTH OF
I-40 AS EXPECTED. HRRR SUGGESTS THAT THE ABQ METRO AREA MAY SEE
SOME ACTION SHORTLY AFTER 00Z...BUT MOST OF THE ACTIVITY SHOULD
END BY MIDNIGHT ACROSS ALL AREAS.
STILL LOOKING FOR A BACK DOOR COLD FRONT TO MOVE INTO AT LEAST NE
NM ON TUESDAY BEFORE SLIDING SOUTH AND WEST TUESDAY NIGHT. THE
FRONT CONTINUES TO LOOK STRONGER WITH EACH MODEL RUN...AND A
BREEZY EAST CANYON WIND NOW LOOKS MORE LIKELY EARLY WEDNESDAY
MORNING FOR THE RIO GRANDE VALLEY. THE BIGGEST QUESTION CONTINUES
TO BE HOW MUCH PRECIPITATION WILL ACCOMPANY THE FRONT. GFS
CONTINUES TO BE VERY BULLISH BREAKING OUT STORMS ACROSS MUCH OF
EASTERN NM IN MOIST UPSLOPE FLOW TUESDAY NIGHT. OTHER MODELS ARE
LESS ENTHUSED. IT CERTAINLY SEEMS POSSIBLE SINCE MODELS ARE NOT
SHOWING AS MUCH DRYING AT MID LEVELS AS THEY WERE
YESTERDAY...EXCEPT FOR IN THE FAR NW. GIVING A NOD TO THE GFS
ENSEMBLE MEMBERS...WHICH ARE MUCH LIKE THEIR OPERATIONAL
COUNTERPART... BUMPED UP POPS A BIT MORE ACROSS THE EAST.
MOST MODELS NOW SHOWING CONVECTION ALONG THE CENTRAL MTN CHAIN ON
WEDNESDAY AFTERNOON WITH CONTINUED MOIST UPSLOPE FLOW. STORMS
SHOULD BE MORE ROBUST SOUTH OF I-40 WHERE MID LEVEL DRYING IS NOT
AS PREVALENT. HIGH TEMPERATURES ON WEDNESDAY SHOULD DROP AT LEAST
3 TO 8 DEGREES FROM TUESDAYS READINGS...THOUGH THIS WILL MEAN
TEMPS WILL ACTUALLY BE RIGHT AROUND NORMAL.
THE MID LEVEL DRY AIR NUDGES IN FARTHER ON THURSDAY...AND
CONVECTIVE COVERAGE SHOULD WANE A BIT. AREAS SOUTH OF HWY 60
SHOULD HAVE THE BEST STORM CHANCES. THEREAFTER...CONFIDENCE
REMAINS VERY LOW AS MODELS CONTINUE TO YO-YO THE NEXT BACK DOOR
FRONT AROUND. THE ECMWF IS BACK ON SCHEDULE FOR THE FRONT TO
ARRIVE ON FRIDAY...WHILE THE GFS IS AROUND 12 HOURS LATER AND ALSO
MUCH STRONGER. THIS WILL OBVIOUSLY HAVE SERIOUS IMPLICATION ON
POPS AND TEMPS...SO GENERALLY WENT FOR A MIDDLE OF THE ROAD
FORECAST FOR NOW.
34
&&
.FIRE WEATHER...
HIGH PRESSURE ALOFT IS FORECAST TO BUILD INTO THE GREAT BASIN THIS
WEEK...EVENTUALLY CUTTING OFF THE FLOW OF MOISTURE FROM THE
SOUTH...WHILE SHUNTING HURRICANE LINDA WEST OF BAJA CA/SOCAL. THIS
SHOULD LEAD TO A DRYING TREND FOR WESTERN NEW MEXICO. LOW LEVEL
MOISTURE WILL SLOSH BACK AND FORTH OVER CENTRAL AND EASTERN NEW
MEXICO THIS WEEK...DEPENDING ON TIMING OF 2 BOUNDARIES...ONE
EXPECTED TUESDAY/TUESDAY NIGHT AND A SECOND...WHICH THE GFS IS NOW
PORTRAYING AS STRONGER THAN IT HAS IN SEVERAL RUNS...ON
FRIDAY/FRIDAY NIGHT.
SO FAR THIS AFTERNOON...MOST OF THE CONVECTION HAS BEEN RELEGATED TO
AREAS ALONG AND SOUTH OF INTERSTATE 40...AS THE HRRR SUGGESTED.
WETTING RAIN FOOTPRINTS TO BE FAIRLY SMALL AS CELLS TRACK TO THE
EAST/NORTHEAST...AND ACTIVITY IS INDICATED TO DIMINISH BY MID
EVENING.
TUESDAY/WEDNESDAY ARE TRANSITION DAYS IN WHICH THE UPPER AIR PATTERN
SHIFTS FROM WEST TO NORTHWEST/NORTH WINDS ALOFT...IMPORTING
CONSIDERABLY DRIER AIR AT THE MID LEVELS. THE SURFACE BOUNDARY FOR
TUESDAY/TUESDAY NIGHT APPEARS A BIT MORE VIGOROUS AND MAY PUSH SOME
LOW LEVEL MOISTURE INTO THE RGV...WHICH MIXES OUT TO SOME EXTENT
WEDNESDAY...WHEN BEST CHANCES FOR WETTING RAIN WILL BECOME FOCUSED
ALONG THE CENTRAL MT CHAIN AND SOUTH OF I-40. PRECIPITATION CHANCES
TAPER DOWN THURSDAY INTO FRIDAY...BUT ANOTHER BOUNDARY COULD
REPLENISH LOW LEVEL MOISTURE INTO THE CENTRAL/EAST BY SATURDAY.
TOWARDS THE END OF THIS WEEK...AND INTO NEXT WEEK...FORECAST
VARIABLES CONTINUE TO BE QUITE VARIABLE WITH RUN TO RUN MODEL FLIP
FLOPPING. THE 12Z GFS DEVELOPS A VIGOROUS SHORT WAVE/CLOSED LOW ON
THE EASTERN PERIPHERY OF THE UPPER RIDGE OVER ERN NM/CHIHUAHUA THIS
WEEKEND THEN EJECTS IT NEWD EARLY NEXT WEEK. THE ECMWF HAS OTHER
IDEAS...MAINLY A 590 PLUS HIGH CENTER OVER NM. IN FACT...THE DEEP
UPPER TROF DEPICTED 24 HRS AGO BY BOTH NEAR 240 HRS HAS VANISHED.
KEEPING THE LOW CONFIDENCE IN MIND...HIGH HAINES WILL BE FOUND OVER
PORTIONS OF CENTRAL AND WRN NM MID TO LATE THIS WEEK. POOR OVERNIGHT
RECOVERIES WILL PLAGUE PORTIONS OF THE NW DURING THIS TIME...AND MIN
RH VALUES MAY FALL BELOW 15 PERCENT. HIGHS WILL BE CLOSE TO AVERAGE
FOR THE SEASON THROUGH THE UPCOMING WEEKEND. OVERNIGHT LOWS MAY FALL
TO NEAR FREEZING AT SOME OF THE NRN MT HIGHER TERRAIN OBS SITES MID
TO LATE WEEK. VENT RATES FORECAST TO BE GOOD TO EXCELLENT
TUESDAY...THEN DECREASE WEDNESDAY WITH AREAS OF FAIR TO POOR
FORECAST ALONG AND SOUTH OF I-40. WIDESPREAD FAIR TO POOR RATES
ANTICIPATED FRIDAY CENTRAL AND EAST.
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
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...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 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 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 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 BISMARCK ND
925 PM CDT MON SEP 7 2015
.UPDATE...
ISSUED AT 918 PM CDT MON SEP 7 2015
ONE STRONG THUNDERSTORM REMAINS OVER FAR SOUTHWEST DICKEY IN THE
APEX OF AN AXIS OF INSTABILITY EXTENDING INTO SOUTH DAKOTA.
LATEST MESO-ANALYSIS INDICATES THE STORM MAY NOW BE MOVING AHEAD
OF THE GREATEST INSTABILITY...ALTHOUGH SHEAR REMAINS ABUNDANT.
HAVE EXTENDED THUNDERSTORM CHANCES THROUGH 04Z ACROSS SOUTHERN
DICKEY COUNTY.
SHOWERS HAVE ALL BUT DISSIPATED ACROSS THE NORTHWEST AND NORTH
CENTRAL. COULD STILL SEE A SPRINKLE OR TWO THIS EVENING BUT NOT
ENOUGH COVERAGE TO KEEP A MENTION OF MEASURABLE PRECIPITATION.
UPDATE ISSUED AT 701 PM CDT MON SEP 7 2015
QUICK UPDATE TO ADD A MENTION OF THUNDER FOR A FEW HOURS THIS
EVENING OVER THE FAR SOUTH CENTRAL FROM AROUND STRASBURG ACROSS
MCINTOSH AND INTO DICKEY COUNTY. AXIS OF INSTABILITY OVER CENTRAL
SOUTH DAKOTA IS EXTENDING INTO THE FAR SOUTH CENTRAL WITH GOOD
BULK SHEAR OVER THE AREA. THIS SHOULD BE A SHORT LIVED EVENT
ENCOMPASSING THIS SMALL AREA.
UPDATE ISSUED AT 632 PM CDT MON SEP 7 2015
AFTERNOON SHOWERS HAVE EXITED EASTERN PORTIONS OF CENTRAL NORTH
DAKOTA. A FEW SHOWERS WERE LOCATED OVER NORTHEAST MONTANA INTO FAR
NORTHWEST NORTH DAKOTA ASSOCIATED WITH A SHORTWAVE ROTATING
AROUND THE BASE OF THE UPPER LEVEL LOW OVER MANITOBA. MOST LIKELY
NOTHING MORE THAN A SPRINKLE OR BRIEF SHOWER EXPECTED HERE BUT DID
KEEP SOME SLIGHT CHANCE POPS OVER THE NORTHWEST EARLY THIS
EVENING. ALSO BUMPED UP SKY COVER A BIT OVER THE NORTHWEST.
OTHERWISE NO SIGNIFICANT UPDATES TO THE GOING FORECAST.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 256 PM CDT MON SEP 7 2015
RAIN SHOWERS ENDING BY EARLY THIS EVENING CENTRAL HIGHLIGHT THE
SHORT TERM FORECAST.
WILL CONTINUE TO RELY ON A TIME LAGGED ENSEMBLE OF THE HRRR FOR
POPS THE REMAINDER OF THE AFTERNOON...NAMELY ITS 16-18 UTC
ITERATIONS...WHICH HAS DONE WELL THROUGHOUT THE DAY. DID MAINTAIN
A SLIGHT CHANCE OF THUNDER WITH A FEW...SPORADIC LIGHTNING
STRIKES OBSERVED. EXPECT PRECIPITATION CHANCES...FOCUSED PRIMARILY
ACROSS NORTH CENTRAL NORTH DAKOTA AND THE UPPER JAMES RIVER VALLEY
THE REST OF THE DAY...TO RAPIDLY DECREASE BY 22-23 UTC AS FORCING
FROM TWO SHORTWAVES SOUTH OF THE UPPER LOW NEAR LAKE WINNIPEG
SHIFTS EAST.
FOR TUESDAY...A QUIET...DRY...ALBEIT SLIGHTLY BELOW NORMAL
TEMPERATURE-WISE DAY IS FORECAST SOUTH OF THE NOW FILLING
AFOREMENTIONED LOW. GIVEN GOOD AGREEMENT...UTILIZED A BLEND OF THE
12 UTC GUIDANCE SUITES FOR ALL FIELDS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 256 PM CDT MON SEP 7 2015
NORTHWEST FLOW ALOFT THROUGH FRIDAY WITH FLOW ROTATING AROUND THE
HUDSON BAY LOW AND RIDGE OVER THE EASTERN PACIFIC AND WEST COAST.
SHORTWAVE ENERGY MOVING THROUGH THIS FLOW APPROACHES NORTHERN NORTH
DAKOTA LATE TUESDAY NIGHT/WEDNESDAY MORNING...WITH AN ATTENDANT WEAK
SURFACE LOW AND COLD FRONT. MORE SHORTWAVE ENERGY IMPULSES MOVE
SOUTHEAST ACROSS THE STATE WEDNESDAY AFTERNOON WITH A COLD FRONT
MOVING SOUTH ACROSS THE STATE. THIS WILL RESULT IN SLIGHT CHANCES OF
SHOWERS...MAINLY NORTHWEST AND CENTRAL...ON WEDNESDAY. SEASONABLE
TEMPERATURES WEDNESDAY WITH HIGHS FROM THE UPPER 60S NORTH TO UPPER
70S SOUTH.
ANOTHER SERIES OF SHORTWAVES MOVES ACROSS THE STATE WEDNESDAY NIGHT
WITH A SECONDARY PUSH OF COLD AIR IN THE FORM OF A BACKDOOR COLD
FRONT MOVING SOUTHWEST ACROSS THE STATE. SLIGHT CHANCES OF SHOWERS
WILL REMAIN IN THE FORECAST NORTHWEST AND CENTRAL WEDNESDAY
NIGHT...WITH MAINLY DRY BUT COOL CONDITIONS EXPECTED THURSDAY. LOOK
FOR HIGHS IN THE 60S TO LOWER 70S.
THE UPPER LEVEL WESTERN RIDGE BUILDS BACK INTO THE REGION FOR THE
WEEKEND...WITH DRY CONDITIONS AND SLIGHTLY ABOVE AVERAGE
TEMPERATURES. HIGHS IN THE 70S TO LOWER 80S.
THE MODELS BRING AN UPPER LEVEL SHORTWAVE MOVING THROUGH THE
FLOW...FLATTENING THE RIDGE...BRINGING A CHANCE OF SHOWERS AND
COOLER WEATHER FOR MONDAY WITH HIGHS MAINLY IN THE 60S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 918 PM CDT MON SEP 7 2015
VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD. MID LEVEL
CLOUD COVER EXITING CENTRAL NORTH DAKOTA EARLY THIS EVENING.
ADDITIONAL MID LEVEL CLOUD WILL INCREASE OVER NORTHWEST AND NORTH
CENTRAL NORTH DAKOTA THIS EVENING WITH AN ISOLATED SHOWER POSSIBLE
BUT TOO SCARCE TO MENTION IN KISN OR KMOT TAF. PATCHY FOG MAY BE
POSSIBLE AT KBIS/KJMS TONIGHT. HOWEVER...GIVEN HIGH
UNCERTAINTY...LEFT IT OUT OF THE TAFS FOR NOW.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...AYD
LONG TERM...JV
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
705 PM CDT MON SEP 7 2015
.UPDATE...
ISSUED AT 701 PM CDT MON SEP 7 2015
QUICK UPDATE TO ADD A MENTION OF THUNDER FOR A FEW HOURS THIS
EVENING OVER THE FAR SOUTH CENTRAL FROM AROUND STRASBURG ACROSS
MCINTOSH AND INTO DICKEY COUNTY. AXIS OF INSTABILITY OVER CENTRAL
SOUTH DAKOTA IS EXTENDING INTO THE FAR SOUTH CENTRAL WITH GOOD
BULK SHEAR OVER THE AREA. THIS SHOULD BE A SHORT LIVED EVENT
ENCOMPASSING THIS SMALL AREA.
UPDATE ISSUED AT 632 PM CDT MON SEP 7 2015
AFTERNOON SHOWERS HAVE EXITED EASTERN PORTIONS OF CENTRAL NORTH
DAKOTA. A FEW SHOWERS WERE LOCATED OVER NORTHEAST MONTANA INTO FAR
NORTHWEST NORTH DAKOTA ASSOCIATED WITH A SHORTWAVE ROTATING
AROUND THE BASE OF THE UPPER LEVEL LOW OVER MANITOBA. MOST LIKELY
NOTHING MORE THAN A SPRINKLE OR BRIEF SHOWER EXPECTED HERE BUT DID
KEEP SOME SLIGHT CHANCE POPS OVER THE NORTHWEST EARLY THIS
EVENING. ALSO BUMPED UP SKY COVER A BIT OVER THE NORTHWEST.
OTHERWISE NO SIGNIFICANT UPDATES TO THE GOING FORECAST.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 256 PM CDT MON SEP 7 2015
RAIN SHOWERS ENDING BY EARLY THIS EVENING CENTRAL HIGHLIGHT THE
SHORT TERM FORECAST.
WILL CONTINUE TO RELY ON A TIME LAGGED ENSEMBLE OF THE HRRR FOR
POPS THE REMAINDER OF THE AFTERNOON...NAMELY ITS 16-18 UTC
ITERATIONS...WHICH HAS DONE WELL THROUGHOUT THE DAY. DID MAINTAIN
A SLIGHT CHANCE OF THUNDER WITH A FEW...SPORADIC LIGHTNING
STRIKES OBSERVED. EXPECT PRECIPITATION CHANCES...FOCUSED PRIMARILY
ACROSS NORTH CENTRAL NORTH DAKOTA AND THE UPPER JAMES RIVER VALLEY
THE REST OF THE DAY...TO RAPIDLY DECREASE BY 22-23 UTC AS FORCING
FROM TWO SHORTWAVES SOUTH OF THE UPPER LOW NEAR LAKE WINNIPEG
SHIFTS EAST.
FOR TUESDAY...A QUIET...DRY...ALBEIT SLIGHTLY BELOW NORMAL
TEMPERATURE-WISE DAY IS FORECAST SOUTH OF THE NOW FILLING
AFOREMENTIONED LOW. GIVEN GOOD AGREEMENT...UTILIZED A BLEND OF THE
12 UTC GUIDANCE SUITES FOR ALL FIELDS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 256 PM CDT MON SEP 7 2015
NORTHWEST FLOW ALOFT THROUGH FRIDAY WITH FLOW ROTATING AROUND THE
HUDSON BAY LOW AND RIDGE OVER THE EASTERN PACIFIC AND WEST COAST.
SHORTWAVE ENERGY MOVING THROUGH THIS FLOW APPROACHES NORTHERN NORTH
DAKOTA LATE TUESDAY NIGHT/WEDNESDAY MORNING...WITH AN ATTENDANT WEAK
SURFACE LOW AND COLD FRONT. MORE SHORTWAVE ENERGY IMPULSES MOVE
SOUTHEAST ACROSS THE STATE WEDNESDAY AFTERNOON WITH A COLD FRONT
MOVING SOUTH ACROSS THE STATE. THIS WILL RESULT IN SLIGHT CHANCES OF
SHOWERS...MAINLY NORTHWEST AND CENTRAL...ON WEDNESDAY. SEASONABLE
TEMPERATURES WEDNESDAY WITH HIGHS FROM THE UPPER 60S NORTH TO UPPER
70S SOUTH.
ANOTHER SERIES OF SHORTWAVES MOVES ACROSS THE STATE WEDNESDAY NIGHT
WITH A SECONDARY PUSH OF COLD AIR IN THE FORM OF A BACKDOOR COLD
FRONT MOVING SOUTHWEST ACROSS THE STATE. SLIGHT CHANCES OF SHOWERS
WILL REMAIN IN THE FORECAST NORTHWEST AND CENTRAL WEDNESDAY
NIGHT...WITH MAINLY DRY BUT COOL CONDITIONS EXPECTED THURSDAY. LOOK
FOR HIGHS IN THE 60S TO LOWER 70S.
THE UPPER LEVEL WESTERN RIDGE BUILDS BACK INTO THE REGION FOR THE
WEEKEND...WITH DRY CONDITIONS AND SLIGHTLY ABOVE AVERAGE
TEMPERATURES. HIGHS IN THE 70S TO LOWER 80S.
THE MODELS BRING AN UPPER LEVEL SHORTWAVE MOVING THROUGH THE
FLOW...FLATTENING THE RIDGE...BRINGING A CHANCE OF SHOWERS AND
COOLER WEATHER FOR MONDAY WITH HIGHS MAINLY IN THE 60S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 632 PM CDT MON SEP 7 2015
VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD. MID LEVEL
CLOUD COVER EXITING CENTRAL NORTH DAKOTA EARLY THIS EVENING.
ADDITIONAL MID LEVEL CLOUD WILL INCREASE OVER NORTHWEST AND NORTH
CENTRAL NORTH DAKOTA THIS EVENING WITH AN ISOLATED SHOWER POSSIBLE
BUT TOO SCARCE TO MENTION IN KISN OR KMOT TAF. PATCHY FOG MAY BE
POSSIBLE AT KBIS/KJMS TONIGHT. HOWEVER...GIVEN HIGH
UNCERTAINTY...LEFT IT OUT OF THE TAFS FOR NOW.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...AYD
LONG TERM...JV
AVIATION...TWH/DD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
642 PM CDT MON SEP 7 2015
.UPDATE...
ISSUED AT 632 PM CDT MON SEP 7 2015
AFTERNOON SHOWERS HAVE EXITED EASTERN PORTIONS OF CENTRAL NORTH
DAKOTA. A FEW SHOWERS WERE LOCATED OVER NORTHEAST MONTANA INTO FAR
NORTHWEST NORTH DAKOTA ASSOCIATED WITH A SHORTWAVE ROTATING
AROUND THE BASE OF THE UPPER LEVEL LOW OVER MANITOBA. MOST LIKELY
NOTHING MORE THAN A SPRINKLE OR BRIEF SHOWER EXPECTED HERE BUT DID
KEEP SOME SLIGHT CHANCE POPS OVER THE NORTHWEST EARLY THIS
EVENING. ALSO BUMPED UP SKY COVER A BIT OVER THE NORTHWEST.
OTHERWISE NO SIGNIFICANT UPDATES TO THE GOING FORECAST.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 256 PM CDT MON SEP 7 2015
RAIN SHOWERS ENDING BY EARLY THIS EVENING CENTRAL HIGHLIGHT THE
SHORT TERM FORECAST.
WILL CONTINUE TO RELY ON A TIME LAGGED ENSEMBLE OF THE HRRR FOR
POPS THE REMAINDER OF THE AFTERNOON...NAMELY ITS 16-18 UTC
ITERATIONS...WHICH HAS DONE WELL THROUGHOUT THE DAY. DID MAINTAIN
A SLIGHT CHANCE OF THUNDER WITH A FEW...SPORADIC LIGHTNING
STRIKES OBSERVED. EXPECT PRECIPITATION CHANCES...FOCUSED PRIMARILY
ACROSS NORTH CENTRAL NORTH DAKOTA AND THE UPPER JAMES RIVER VALLEY
THE REST OF THE DAY...TO RAPIDLY DECREASE BY 22-23 UTC AS FORCING
FROM TWO SHORTWAVES SOUTH OF THE UPPER LOW NEAR LAKE WINNIPEG
SHIFTS EAST.
FOR TUESDAY...A QUIET...DRY...ALBEIT SLIGHTLY BELOW NORMAL
TEMPERATURE-WISE DAY IS FORECAST SOUTH OF THE NOW FILLING
AFOREMENTIONED LOW. GIVEN GOOD AGREEMENT...UTILIZED A BLEND OF THE
12 UTC GUIDANCE SUITES FOR ALL FIELDS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 256 PM CDT MON SEP 7 2015
NORTHWEST FLOW ALOFT THROUGH FRIDAY WITH FLOW ROTATING AROUND THE
HUDSON BAY LOW AND RIDGE OVER THE EASTERN PACIFIC AND WEST COAST.
SHORTWAVE ENERGY MOVING THROUGH THIS FLOW APPROACHES NORTHERN NORTH
DAKOTA LATE TUESDAY NIGHT/WEDNESDAY MORNING...WITH AN ATTENDANT WEAK
SURFACE LOW AND COLD FRONT. MORE SHORTWAVE ENERGY IMPULSES MOVE
SOUTHEAST ACROSS THE STATE WEDNESDAY AFTERNOON WITH A COLD FRONT
MOVING SOUTH ACROSS THE STATE. THIS WILL RESULT IN SLIGHT CHANCES OF
SHOWERS...MAINLY NORTHWEST AND CENTRAL...ON WEDNESDAY. SEASONABLE
TEMPERATURES WEDNESDAY WITH HIGHS FROM THE UPPER 60S NORTH TO UPPER
70S SOUTH.
ANOTHER SERIES OF SHORTWAVES MOVES ACROSS THE STATE WEDNESDAY NIGHT
WITH A SECONDARY PUSH OF COLD AIR IN THE FORM OF A BACKDOOR COLD
FRONT MOVING SOUTHWEST ACROSS THE STATE. SLIGHT CHANCES OF SHOWERS
WILL REMAIN IN THE FORECAST NORTHWEST AND CENTRAL WEDNESDAY
NIGHT...WITH MAINLY DRY BUT COOL CONDITIONS EXPECTED THURSDAY. LOOK
FOR HIGHS IN THE 60S TO LOWER 70S.
THE UPPER LEVEL WESTERN RIDGE BUILDS BACK INTO THE REGION FOR THE
WEEKEND...WITH DRY CONDITIONS AND SLIGHTLY ABOVE AVERAGE
TEMPERATURES. HIGHS IN THE 70S TO LOWER 80S.
THE MODELS BRING AN UPPER LEVEL SHORTWAVE MOVING THROUGH THE
FLOW...FLATTENING THE RIDGE...BRINGING A CHANCE OF SHOWERS AND
COOLER WEATHER FOR MONDAY WITH HIGHS MAINLY IN THE 60S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 632 PM CDT MON SEP 7 2015
VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD. MID LEVEL
CLOUD COVER EXITING CENTRAL NORTH DAKOTA EARLY THIS EVENING.
ADDITIONAL MID LEVEL CLOUD WILL INCREASE OVER NORTHWEST AND NORTH
CENTRAL NORTH DAKOTA THIS EVENING WITH AN ISOLATED SHOWER POSSIBLE
BUT TOO SCARCE TO MENTION IN KISN OR KMOT TAF. PATCHY FOG MAY BE
POSSIBLE AT KBIS/KJMS TONIGHT. HOWEVER...GIVEN HIGH
UNCERTAINTY...LEFT IT OUT OF THE TAFS FOR NOW.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...AYD
LONG TERM...JV
AVIATION...TWH/DD
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
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 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 CLEVELAND OH
907 PM EDT MON SEP 7 2015
.SYNOPSIS...
HIGH PRESSURE ALONG THE MID-ATLANTIC WILL WEAKEN AS IT MOVES TO THE
SOUTHEASTERN STATES THROUGH MID-WEEK. A SLOW MOVING COLD FRONT OVER
THE CENTRAL GREAT LAKES WILL STALL NORTH OF LAKE ERIE ON TUESDAY. A
WAVE OF LOW PRESSURE WILL MOVE NORTHEAST ALONG THE BOUNDARY ON
WEDNESDAY AND PULL THE FRONT SOUTH ACROSS THE AREA.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... WILL CONTINUE TO IGNORE
THE OVERDONE HRRR AND RAP THAT HAVE BEEN TRYING TO DEVELOP SCT
CONVECTION AROUND THE CWA ALL AFTERNOON AND EVENING.
A SLOW MOVING COLD FRONT IS EXPECTED TO STALL TONIGHT JUST NORTH OF
LAKE ERIE. CONVECTION ALONG THE DIFFERENTIAL HEATING BOUNDARY ON THE
LEADING EDGE OF THE FRONT WILL APPROACH AS THE FRONT SINKS SOUTH BUT
IS GENERALLY EXPECTED TO REMAIN NORTH OF OHIO AS IT OUTPACES THE
FRONT/MOISTURE AXIS WITH SOUTHWESTERLY FLOW THROUGH THE COLUMN
ALOFT. CAN NOT ENTIRELY RULE OUT SOMETHING CLIPPING THE TOLEDO AREA
OR SNEAKING OFF THE LAKE TOWARDS ERIE PA SO WILL CONTINUE WITH A LOW
20 POP IN THOSE AREAS.
DEWPOINTS SHOULD INCH UP IN NORTHWEST OHIO AND WITH INCREASING HIGH
CLOUD WILL KEEP MINS SLIGHTLY WARMER NEAR 70 DEGREES...EXTENDING
EAST ALONG THE LAKESHORE. INLAND NE OHIO WILL BOTTOM OUT IN THE
LOWER TO MID 60S.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY NIGHT/...
ALTHOUGH SURFACE BOUNDARY AND LARGER SCALE FORCING REMAINS WEST OF
THE AREA ON TUESDAY...ADDED A SLIGHT CHANCE ACROSS NORTHERN COUNTIES
AS LOW LEVEL THETA-E AXIS SINKS SOUTH. EXPECT CONVECTION TO DEVELOP
ACROSS NORTHERN INDIANA AND LOWER MICHIGAN AS SHORTWAVE ENERGY LIFTS
NORTHEAST ACROSS THAT AREA. SOME OF THE UPSTREAM CONVECTION MAY
START TO TRICKLE INTO NORTHWEST OHIO BY EVENING...ESPECIALLY IF
OUTFLOW BOUNDARIES START TO MOVE OUT AHEAD OF THE FRONT SO DID
INCLUDE A CHANCE POP IN NW OHIO AND SLIGHT CHANCE POPS ACROSS THE
NORTHERN COUNTIES. TEMPERATURES WILL BE HOT FOR ONE MORE DAY IN THE
UPPER 80S TO NEAR 90.
A PRETTY GOOD PIECE OF SHORTWAVE ENERGY WILL ROUND THE TROUGH AND
LIFT NORTHEAST ACROSS THE AREA ON WEDNESDAY. THIS OCCURS AS THE
FRONT PUSHES SOUTH AND SHOULD RESULT IN GOOD COVERAGE OF SHOWERS AND
THUNDERSTORMS. KEPT POPS IN THE 60-70 PERCENT RANGE FOR THE DAYTIME
ON WEDNESDAY. SHEAR INCREASES FROM THE WEST LATER IN THE DAY BUT THE
BETTER STORMS MAY BE OUT AHEAD OF THIS AREA WHERE THERE IS MORE
HEATING AND INSTABILITY. NOT INCLUDED IN A SLIGHT RISK AT THIS TIME
BUT COULD ANTICIPATE A FEW STRONG TO SEVERE STORMS IF WE ACHIEVE
SUFFICIENT HEATING. THE CLOUDS AND COVERAGE OF STORMS WILL LIMIT
HIGHS TO THE UPPER 70S TO LOW 80S.
THE FRONT PUSHES SOUTH WEDNESDAY NIGHT AND WE SHOULD DRY OUT ON
THURSDAY. HELD ONTO A LOW CHANCE POP ON THURSDAY IN MOSTLY IN
INTERIOR EASTERN AREAS AS LOW LEVEL DRY AIR PUSHES IN FROM THE
NORTH. TEMPERATURES WILL FINALLY BE BACK CLOSER TO NORMAL VALUES IN
THE LOWER TO MID 70S.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
THE NEXT UPPER LEVEL TROUGH WILL BE DIGGING INTO THE CENTRAL GREAT
LAKES ON FRIDAY. THE EXTENDED MODELS DIFFER IN THE STRENGTH OF THE
STORM SYSTEM MOVING THROUGH THE REGION WHICH WILL HAVE IMPACTS ON
RAIN CHANCES. IN ANY EVENT THERE WILL AT LEAST BE ISOLATED TO
SCATTERED SHOWERS FRIDAY AFTERNOON THROUGH FRIDAY. THE BETTER
CHANCES AT THE MOMENT SEEM TO BE ACROSS NE OHIO AND NW PA.
FRIDAY WILL BE THE WARM DAY OF THE LONG TERM WITH HIGHS INTO THE
MIDDLE 70S AT MOST LOCATIONS. IT WILL THEN BE COOLER SATURDAY INTO
SUNDAY WITH HIGHS GENERALLY WITHIN A COUPLE DEGREES OF 70. A FEW
LOCATIONS COULD SEE LOWS INTO THE 40S SUNDAY MORNING.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
HIGH PRESSURE ALOFT WILL REMAIN NEARLY STATIONARY INTO TUESDAY
WITH THE SURFACE HIGH ALONG THE EAST COAST PROVIDING A SOUTH TO
SOUTHWEST FLOW. A FEW SPOTS WILL HAVE MVFR FOG/HAZE AROUND
DAYBREAK. TUESDAY WILL BRING PATCHES OF VFR CUMULUS AND SOME HIGH
CLOUDS.
OUTLOOK...NON VFR LIKELY IN SHRA/TSRA WITH A COLD FRONT WEDNESDAY.
NON VFR MAY LINGER INTO THURSDAY MORNING. NON-VFR POSSIBLE ON
SATURDAY WITH THE NEXT COLD FRONT.
&&
.MARINE...
HIGH PRESSURE WILL CONTINUE TO MOVE SOUTHWARD FROM THE MIDDLE
ATLANTIC STATES. THIS WILL ALLOW A COLD FRONT TO MOVE INTO THE
CENTRAL GREAT LAKES LATE MONDAY INTO TUESDAY. SOUTHWESTERLY WINDS
AHEAD OF THE FRONT WILL INCREASE ON MONDAY INTO TUESDAY. AS THE FRONT
PASSES WEDNESDAY EVENING WEST TO NORTHWEST WINDS MAY TOP OUT IN THE
15 TO 20 KNOT RANGE WHICH WILL GET WAVES CLOSE TO SMALL CRAFT
CRITERIA. IF THIS DOES OCCUR IT WILL BE OVERNIGHT WEDNESDAY NIGHT
INTO THURSDAY MORNING. HIGH PRESSURE WILL THEN BRIEFLY RIDGE ACROSS
LAKE ERIE FROM THE UPPER GREAT LAKES THURSDAY INTO FRIDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KEC
NEAR TERM...KEC/ADAMS
SHORT TERM...KEC
LONG TERM...MULLEN
AVIATION...KOSARIK
MARINE...MULLEN
AREA FORECAST DISCUSSION
NWS TULSA OK
831 PM CDT MON SEP 7 2015
.UPDATE...
Pops have been removed for the evening hours and the heat headline
has been cancelled. See discussion below.
&&
.DISCUSSION...
Temps have cooled with the loss of daytime heating and thus the
heat headline was cancelled. The isolated showers and storms have
also dissipated...and thus pops have been removed for the
evening. Will take a look at the 00z data to determine whether
pops may be needed to the north and west of Tulsa late tonight.
The latest runs of the HRRR do indicate that some high based
activity will slide east along the KS/OK border tonight.
Lacy
&&
.PREV DISCUSSION... /ISSUED 610 PM CDT MON SEP 7 2015/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
For the 0Z TAFs, VFR conditions will prevail at all sites
throughout the 24 hour forecast period. Thunderstorm chances will
increase during the afternoon at our northern TAF sites as a cold
front approaches from the north. Frontal passage will be after
this forecast period.
PREV DISCUSSION... /ISSUED 338 PM CDT MON SEP 7 2015/
DISCUSSION...
Late summer heat will continue into Tuesday with the forecast
trended warmer despite the potential for more extensive cloud
cover tomorrow. Convection will develop across southern KS
tomorrow afternoon and spread southeastward by late afternoon and
early evening. Forecast soundings have steep low level lapse rates
amid a plume of 1.75-2 inch precip water with decreasing deep
layer shear w/ southward extent. This would favor downburst
potential and potential aggressive outflow winds w/ the strongest
storms. This potential will also keep northern locations from
otherwise being just as hot tomorrow.
The actual frontal boundary will become the focus for widespread evening
and overnight convection w/ a trend away from severe weather
potential and more toward locally heavy rain. The boundary will
focus precip toward southern areas Wednesday...with the post
frontal air being cooler but not much drier initially.
The stronger push of drier air arrives late Thurs-Friday
associated with another passing wave. A brief shot of precip may
accompany this wave otherwise dry and pleasant conditions look
likely for next weekend. The GFS is an outlier at this range w/
regards to precip potential and favored the GEM/ECMWF solutions.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 79 95 71 86 / 10 40 80 20
FSM 75 94 73 87 / 10 30 80 70
MLC 77 97 72 86 / 10 20 80 60
BVO 75 94 68 86 / 10 70 80 10
FYV 71 90 69 82 / 10 40 90 60
BYV 72 90 68 82 / 10 50 90 60
MKO 75 95 72 85 / 10 40 80 50
MIO 74 91 69 84 / 10 60 80 20
F10 76 95 71 85 / 10 40 80 30
HHW 76 98 72 87 / 10 20 70 70
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
LONG TERM....30
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
NWS HOUSTON/GALVESTON TX
936 PM CDT MON SEP 7 2015
.DISCUSSION...
FOR THE EVENING UPDATE...ADDED SOME LOW RAIN CHANCES ACROSS THE COASTAL
WATERS AND MATAGORDA BAY FOR THE REST OF THE EVENING AND THE OVERNIGHT
HOURS. SEEING A LITTLE BIT OF ACTIVITY POPPING UP ALONG OUR 60 NM LINE...
AND THE LATEST AVAILABLE HRRR SHOWS MORE ACTION POSSIBLY DEVELOPING
IN THESE WATERS OVERNIGHT. OTHER THAN THAT...NO OTHER MAJOR CHANGES
HAVE BEEN MADE.
GALVESTON GOT ANOTHER 0.77 INCHES OF RAIN TODAY WHICH BRINGS THEIR MONTHLY
TOTAL UP TO 6.78 INCHES. WHAT IS THEIR WETTEST SEPTEMBER ON RECORD?
ONLY 26.01 INCHES IN 1885.
42
&&
.PREV DISCUSSION...
DISCUSSION...
00Z TAF DISCUSSION IN AVIATION SECTION.
AVIATION...
RADAR STILL SHOWING A FEW ISO SHOWERS THAT SHOULD BE DISSIPATING
OVER THE NEXT HR. MAY SEE SOME IMPACTS AT KCLL/KUTS BUT BRIEF.
EXPECT MAINLY VFR CIGS OVERNIGHT WITH POSSIBLY A COUPLE OF HRS OF
MVFR/IFR CIGS OR VSBY FOR THE RURAL TERMINALS. HOUSTON TERMINALS
SHOULD BE VFR WITH MAYBE SOME SCT STRATOCU DECKS.
MOISTURE DOES NOT APPEAR TO BE AS STOUT TOMORROW SO MAY HAVE LESS
ACTIVITY TOMORROW THAN TODAY. NAM/GFS KEEP CONVECTION CONFINED
MORE TO THE COAST IN THE AFTERNOON. MENTION VCSH FOR TERMINALS
ALONG THE COAST AND HOUSTON STARTING 17-18Z AND ENDING IN EVENING.
39
PREV DISCUSSION...
DISCUSSION...
WITH AN UPPER LEVEL SHORTWAVE TROUGH MOVING INTO THE AREA...
SCATTERED SHOWERS WERE DRIFTING SOUTHWESTWARD ACROSS HOUSTON...
TRINITY...AND SAN JACINTO COUNTIES AT 230 PM. ISOLATED TO
SCATTERED SHOWERS WERE ALSO OCCURRING ALONG AND BEHIND THE
SEABREEZE. SOME OF THE EARLIER CONVECTION PUT OUT A DECENT
OUTFLOW WHICH COULD BE SEEN ON THE RADAR EAST OF I-45 AND JUST
NORTH OF I-10.
OVER THE NEXT SEVERAL DAYS...THE UPPER LOW OVER THE FAR
NORTHEASTERN GULF OF MEXICO WILL DRIFT SOUTHWESTWARD. MODEL
CONSENSUS IS FOR THE FAIRLY BROAD LOW TO SHEAR OUT INTO A TROUGH
BY WEDNESDAY. A NORTHWESTERLY FLOW OVER TEXAS WILL HELP PUSH A
FRONTAL BOUNDARY INTO SE TEXAS TOWARD THE END OF THE WEEK. A
PREFRONTAL TROUGH AHEAD OF THE FRONT SHOULD WORK ITS WAY INTO AT
LEAST THE NORTHERN COUNTIES BY LATE THURSDAY. THERE IS SOME
QUESTION AS TO HOW FAR THE ACTUAL FRONT WILL MAKE ITS WAY SOUTH
AND TO HOW FAR WEST THE UPPER TROUGH WILL EVENTUALLY MOVE.
HOWEVER...MODEL CONSENSUS IS FOR DECENT COVERAGE OF SHOWERS AND
THUNDERSTORMS ON THURSDAY WITH SOME OF THE VERY DRY NORTHERN
COUNTIES LIKELY FINALLY RECEIVING SOME RELIEF. SCATTERED COVERAGE
SHOULD PERSIST OVER MOST LOCATIONS THROUGH THE WEEKEND. WITH PW/S
FROM 1.8 TO NEAR 2 INCHES AND A RATHER WEAK WIND PROFILE UP
THROUGH 700MB...LOCALLY HEAVY RAINFALL MAY BECOME A CONCERN FOR AT
LEAST THURSDAY AND FRIDAY.
MARINE...
LIGHT ONSHORE FLOW AND 1-3 FT SEAS WILL PERSIST FOR A GOOD PORTION
OF THE WEEK. ISOLATED TO SCATTERED STORMS ARE POSSIBLE PRIMARILY IN
THE OVERNIGHT/MORNING HOURS INTO THE MIDWEEK TIME PERIOD. EXPECT
BETTER CHANCES OF STORMS DURING THE SECOND HALF OF THE WEEK AS
DEEPER MOISTURE MOVES INTO THE REGION. UNSETTLED WEATHER MAY
CONTINUE INTO THE BEGINNING OF NEXT WEEK AS A COASTAL TROUGH
DEVELOPS OFF THE COAST OF MEXICO AND EJECTS NORTHWARD TOWARD THE
TEXAS COASTLINE. 47
PREV DISCUSSION... /ISSUED 1207 PM CDT MON SEP 7 2015/
AVIATION...
APPROACHING THE CONVECTIVE TEMPS EARLY THIS AFTN AND EXPECT SCT
SHRA/TSRA TO BEGIN DEVELOPING INLAND. VERY ISOLATED STRONGER CELLS
MAY PRODUCE SOME 20-30KT GUSTS. OVERALL CONFIDENCE AS TO
WHERE/WHEN ANY INDIVIDUAL CELL IMPACTS A SPECIFIC TAF SITE IS
LOW...SO WILL JUST MAINTAIN VCSH WORDING AND AMEND AS NEEDED.
CONVECTION SHOULD DISSIPATE WITH LOSS OF HEATING. ISOLATED SPOTS
OF SHALLOW LATE NIGHT FOG POSSIBLE BUT NOT SEEING MUCH OF A
WIDESPREAD THREAT ATTM. SLIGHTLY DRIER AIRMASS IN PLACE TOMORROW
SO WILL LEAVE OUT MENTION OF ANY PRECIP. 47
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 76 95 76 94 75 / 10 20 10 40 50
HOUSTON (IAH) 75 94 75 92 76 / 10 30 10 40 40
GALVESTON (GLS) 81 90 80 89 80 / 20 20 10 40 40
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...42
AVIATION/MARINE...39
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
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 GREEN BAY WI
1052 PM CDT MON SEP 7 2015
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 249 PM CDT MON SEP 7 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A WEAK COLD
FRONT DROPPING SOUTHEAST FROM THE BAY OF GREEN BAY TO WAUTOMA EARLY
THIS AFTERNOON. AHEAD OF THE FRONT...CLOUDS ARE FAIRLY WIDESPREAD WITH
SCT SHOWERS DEVELOPING OVER THE PAST HOUR OVER THE NORTHERN FOX VALLEY.
LOOK FOR THESE SHOWERS TO CONTINUE TO DEVELOP AHEAD OF THE FRONT OVER
THE NEXT FEW HOURS. BEHIND THE FRONT...MORE BREAKS IN THE CLOUDS EXIST...BUT
THE AIRMASS REMAINS RELATIVELY HUMID UNTIL BEHIND A SECONDARY
FRONT OVER FAR NORTHWEST WISCONSIN AND CENTRAL MINNESOTA. AS A
SHORTWAVE OVER COLORADO MOVES NORTHEAST TONIGHT...SHOWER AND THUNDERSTORMS
CHANCES AS WELL AS POTENTIAL FOR HEAVY RAINFALL ARE THE MAIN FORECAST
CONCERNS.
TONIGHT...THE SURFACE COLD FRONT WILL SAG INTO SOUTHERN WISCONSIN
THIS EVENING. WEAK SHORTWAVE ENERGY EMANATING OUT OF COLORADO WILL
LIFT NORTHEAST TONIGHT AND MOVE INTO THE WESTERN GREAT LAKES AFTER
MIDNIGHT. MID-LEVEL FLOW WILL BACK AHEAD OF THE SHORTWAVE CAUSING
AIR TO RISE OVER THE STALLED BOUNDARY. MODELS HAVE BACKED OFF RAIN
CHANCES WITH THEIR 12Z RUNS HOWEVER...SO WILL FOLLOW SUIT BY KEEPING
ONLY VERY LOW CHANCES OVER THE FAR SOUTHERN CWA THROUGH THE EVENING
AND ONLY RAMP UP PRECIP CHANCES INTO THE LOW LIKELY RANGE OVER EAST-
CENTRAL WI AFTER 09Z. WINDS WILL SHIFT TO THE NORTHEAST BRIEFLY
THIS EVENING WHICH WILL PROMOTE SOME DRIER AIR FILTERING IN TO N-C
WISCONSIN. AS WINDS SHIFT AROUND TO THE SOUTHEAST...MORE OF THE
MOIST/TROPICAL AIR WILL GET RECYCLED WESTWARD...WHICH MAY CREATE FOG
ISSUES IN THIS AREA. HOWEVER...MID AND HIGH CLOUDS WILL BE ARRIVING
BY 06Z...SO WHILE LOWER VSBYS ARE LIKELY...THE PROBABILITY FOR
WIDESPREAD DENSE FOG SEEMS PRETTY LOW. WILL KEEP A PATCHY MENTION
IN THE FORECAST. LOWS RANGING FROM THE MID 50S NORTH TO MID 60S
SOUTH.
TUESDAY...THE SHORTWAVE WILL CONTINUE TO QUICKLY ADVANCE NE INTO
LOWER MICHIGAN BY 18Z BUT A WEAK SURFACE LOW TRAVELLING ALONG THE
STALLED BOUNDARY MAY NOT REACH CENTRAL LAKE MICHIGAN UNTIL 18Z.
WEAK MID-LEVEL FGEN NORTH OF THE LOW IN CONCERT WITH UPPER
DIVERGENCE SHOULD CREATE AN AREA OF RAIN WITH EMBEDDED TSTORMS OVER
CENTRAL AND NORTHEAST WI DURING THE MORNING...WHICH WILL EXIT IN THE
AFTERNOON. PWATS WILL REMAIN NEAR 2.0...SO LOCALLY AMOUNTS OF RAIN
UP TO AN INCH LOOK POSSIBLE...MAINLY OVER EAST-CENTRAL WI. BUT IT
LOOKS LIKE THIS POSSIBILITY WILL BE TO THE EAST OF THE DRENCH AREAS
OF CENTRAL WI. SO DO NOT SEE A NEED FOR A FLASH FLOOD WATCH AT THIS
TIME. CLOUDY WITH HIGHS IN THE LOW TO MID 70S.
.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 249 PM CDT MON SEP 7 2015
DRIER AND COOLER AIR WILL RETURN TO THE REGION WEDNESDAY AND
WEDNESDAY NIGHT AS WEAK SURFACE RIDGING ARRIVES FROM THE PLAINS
STATES. A SHARP UPPER TROUGH DIVING SOUTHEAST FROM CANADA SHOULD
INDUCE A WAVE ALONG A COLD FRONT THAT WILL MOVE ACROSS THE AREA
THURSDAY AND THURSDAY NIGHT. CYCLONIC UPPER FLOW MAY KEEP THE
SHOWERS GOING FRIDAY. DRY...SEASONABLE WEATHER IS EXPECTED
SATURDAY AND SUNDAY AS THE UPPER TROUGH EXITS AND SURFACE HIGH
BUILDS IN.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1048 PM CDT MON SEP 7 2015
SHOWERS AND SCT TSTMS ARE EXPECTED TO DEVELOP LATE TONIGHT INTO
TUESDAY MORNING AS AN UPPER LEVEL DISTURBANCE ARRIVES FROM THE
PLAINS. HIGH MOISTURE CONTENT IN THE ATMOSPHERE WILL RESULT IN A
THREAT OF LOCALLY HEAVY RAINFALL WITH TSTMS...ESPECIALLY OVER
CENTRAL AND EAST CENTRAL WI. WILL ONLY CARRY A MENTION OF TSTMS
IN THE GRB/ATW/MTW TAFS ON TUES MORNING AT THIS TIME.
LOW CLOUDS AND PATCHY FOG WILL CONTINUE OVERNIGHT...WITH
CONDITIONS DETERIORATING TO IFR/LIFR AT SOME LOCATIONS. SOME
IMPROVEMENT IN CONDITIONS SHOULD OCCUR DURING THE LATE MORNING...
WITH A RETURN TO VFR EXPECTED AT MOST LOCATIONS BY EARLY TO MID
AFTERNOON.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......RDM
AVIATION.......KIECKBUSCH
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
643 PM CDT MON SEP 7 2015
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 249 PM CDT MON SEP 7 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A WEAK COLD
FRONT DROPPING SOUTHEAST FROM THE BAY OF GREEN BAY TO WAUTOMA EARLY
THIS AFTERNOON. AHEAD OF THE FRONT...CLOUDS ARE FAIRLY WIDESPREAD WITH
SCT SHOWERS DEVELOPING OVER THE PAST HOUR OVER THE NORTHERN FOX VALLEY.
LOOK FOR THESE SHOWERS TO CONTINUE TO DEVELOP AHEAD OF THE FRONT OVER
THE NEXT FEW HOURS. BEHIND THE FRONT...MORE BREAKS IN THE CLOUDS EXIST...BUT
THE AIRMASS REMAINS RELATIVELY HUMID UNTIL BEHIND A SECONDARY
FRONT OVER FAR NORTHWEST WISCONSIN AND CENTRAL MINNESOTA. AS A
SHORTWAVE OVER COLORADO MOVES NORTHEAST TONIGHT...SHOWER AND THUNDERSTORMS
CHANCES AS WELL AS POTENTIAL FOR HEAVY RAINFALL ARE THE MAIN FORECAST
CONCERNS.
TONIGHT...THE SURFACE COLD FRONT WILL SAG INTO SOUTHERN WISCONSIN
THIS EVENING. WEAK SHORTWAVE ENERGY EMANATING OUT OF COLORADO WILL
LIFT NORTHEAST TONIGHT AND MOVE INTO THE WESTERN GREAT LAKES AFTER
MIDNIGHT. MID-LEVEL FLOW WILL BACK AHEAD OF THE SHORTWAVE CAUSING
AIR TO RISE OVER THE STALLED BOUNDARY. MODELS HAVE BACKED OFF RAIN
CHANCES WITH THEIR 12Z RUNS HOWEVER...SO WILL FOLLOW SUIT BY KEEPING
ONLY VERY LOW CHANCES OVER THE FAR SOUTHERN CWA THROUGH THE EVENING
AND ONLY RAMP UP PRECIP CHANCES INTO THE LOW LIKELY RANGE OVER EAST-
CENTRAL WI AFTER 09Z. WINDS WILL SHIFT TO THE NORTHEAST BRIEFLY
THIS EVENING WHICH WILL PROMOTE SOME DRIER AIR FILTERING IN TO N-C
WISCONSIN. AS WINDS SHIFT AROUND TO THE SOUTHEAST...MORE OF THE
MOIST/TROPICAL AIR WILL GET RECYCLED WESTWARD...WHICH MAY CREATE FOG
ISSUES IN THIS AREA. HOWEVER...MID AND HIGH CLOUDS WILL BE ARRIVING
BY 06Z...SO WHILE LOWER VSBYS ARE LIKELY...THE PROBABILITY FOR
WIDESPREAD DENSE FOG SEEMS PRETTY LOW. WILL KEEP A PATCHY MENTION
IN THE FORECAST. LOWS RANGING FROM THE MID 50S NORTH TO MID 60S
SOUTH.
TUESDAY...THE SHORTWAVE WILL CONTINUE TO QUICKLY ADVANCE NE INTO
LOWER MICHIGAN BY 18Z BUT A WEAK SURFACE LOW TRAVELLING ALONG THE
STALLED BOUNDARY MAY NOT REACH CENTRAL LAKE MICHIGAN UNTIL 18Z.
WEAK MID-LEVEL FGEN NORTH OF THE LOW IN CONCERT WITH UPPER
DIVERGENCE SHOULD CREATE AN AREA OF RAIN WITH EMBEDDED TSTORMS OVER
CENTRAL AND NORTHEAST WI DURING THE MORNING...WHICH WILL EXIT IN THE
AFTERNOON. PWATS WILL REMAIN NEAR 2.0...SO LOCALLY AMOUNTS OF RAIN
UP TO AN INCH LOOK POSSIBLE...MAINLY OVER EAST-CENTRAL WI. BUT IT
LOOKS LIKE THIS POSSIBILITY WILL BE TO THE EAST OF THE DRENCH AREAS
OF CENTRAL WI. SO DO NOT SEE A NEED FOR A FLASH FLOOD WATCH AT THIS
TIME. CLOUDY WITH HIGHS IN THE LOW TO MID 70S.
.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 249 PM CDT MON SEP 7 2015
DRIER AND COOLER AIR WILL RETURN TO THE REGION WEDNESDAY AND
WEDNESDAY NIGHT AS WEAK SURFACE RIDGING ARRIVES FROM THE PLAINS
STATES. A SHARP UPPER TROUGH DIVING SOUTHEAST FROM CANADA SHOULD
INDUCE A WAVE ALONG A COLD FRONT THAT WILL MOVE ACROSS THE AREA
THURSDAY AND THURSDAY NIGHT. CYCLONIC UPPER FLOW MAY KEEP THE
SHOWERS GOING FRIDAY. DRY...SEASONABLE WEATHER IS EXPECTED
SATURDAY AND SUNDAY AS THE UPPER TROUGH EXITS AND SURFACE HIGH
BUILDS IN.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 634 PM CDT MON SEP 7 2015
ISOLD SHRA OVER FAR NE AND EC WI WILL END EARLY THIS EVG...BUT
SHRA/SCT TSRA SHOULD REDEVELOP LATE TONIGHT INTO TUESDAY MORNING
AS AN UPPER LEVEL DISTURBANCE ARRIVES FROM THE PLAINS. HIGH
MOISTURE CONTENT IN THE ATMOSPHERE WILL RESULT IN A THREAT OF
LOCALLY HEAVY RAINFALL WITH TSTMS...ESPECIALLY OVER EC WI. WILL
ONLY CARRY A MENTION OF TSTMS AT GRB/ATW/MTW (ON TUES MORNING)
AT THIS TIME.
LOW CLOUDS AND PATCHY FOG WILL LIKELY DEVELOP LATE TONIGHT...
WITH CONDITIONS DETERIORATING TO IFR AT MOST LOCATIONS. SOME
IMPROVEMENT IN CONDITIONS SHOULD OCCUR DURING THE LATE MORNING
AND AFTERNOON...WITH A RETURN TO VFR EXPECTED AT MOST LOCATIONS
BY MID AFTERNOON.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......RDM
AVIATION.......KIECKBUSCH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
607 PM CDT MON SEP 7 2015
.SHORT TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 305 PM CDT MON SEP 7 2015
A WARM FRONT WAS HUNG UP OVER SOUTHERN IA...STRETCHING INTO SOUTHERN
WI. THE LOW LEVEL JET WILL INCREASE THIS EVENING...PUSHING INTO AND
ACROSS THE BOUNDARY. A LOFT...THE RIGHT ENTRANCE REGION OF A 300 MB
JET STREAK WILL ENHANCE THE AVAILABLE LIFT. HIGH PWS OF 2 INCHES...A
+2 ANOMALY VIA NAEFS...WITH WARM CLOUD DEPTHS OF 4 KFT...AROUND AND
NORTH OF THE FRONT. A RIPPLE IN THE UPPER LEVEL FLOW IS ALSO PROGGED
TO SLIDE FROM THE SOUTHERN PLAINS TO ACROSS THIS FRONT OVERNIGHT.
ALL THIS SHOULD RESULT IN A BLOSSOMING AREA OF SHOWERS AND
THUNDERSTORMS...CAPABLE OF HEAVY RAIN. MESO MODELS TRENDS FAVOR
KEEPING THE BULK OF THE PCPN THREAT ALONG AND SOUTH OF I-90...WITH
THE HEAVY RAIN MOSTLY CONFINED TO IOWA.
MODEL TRENDS HAVE BEEN SLOWING THIS SYSTEM DOWN A BIT OVER THE PAST
FEW DAYS...AND EXPECT PCPN TO LINGER ACROSS THE EAST TUE MORNING.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 305 PM CDT MON SEP 7 2015
DOWNTURN IN THE TEMPERATURES AS LARGE SCALE PATTERN SHIFT FROM
RIDGING TO TROUGH/NORTHWEST FLOW CONTINUES. 850 MB TEMPS ARE
EXPECTED TO DROP FROM 18 C AT 00Z TUE TO 5 C BY 00Z SAT. NAEFS 850
MB TEMP ANOMALIES HOVER NEAR -1 THU THROUGH THE WEEKEND. A DAY OR
TWO WITH HIGHS ONLY IN THE 60S AND LOWS IN THE 40S ARE EXPECTED -
WITH FRI/SAT MORNING LOOKING LIKE THE COOLEST PERIOD.
VARIOUS RIPPLES WILL MOVE ALONG THE NORTHWEST FLOW...WITH PREVIOUS
MODEL RUNS TAKING THEM MOSTLY NORTH/SOUTH OF THE LOCAL AREA...OR
WEAKENING THEM AS THEY MOVED IN. LAST RUN OR TWO THEY HAVE CHANGED
THEIR TUNE. THE GFS/GEM/ECMWF ALL SLIDE AN UPPER LEVEL SHORTWAVE
ACROSS THE UPPER MISSISSIPPI RIVER VALLEY THU/FRI. THAT AND A
RELATED SFC BOUNDARY COULD SPARK SHOWERS/STORMS AS IT MOVES THROUGH.
NOT MUCH INSTABILITY...SO IF PCPN DEVELOPS...MORE ON THE SHOWER THAN
THUNDERSTORM SIDE. SHOWERS COULD LINGER/REDEVELOP ON FRIDAY IN WRAP
AROUND REGION OF THE SFC LOW/FAVORABLE LOW LEVEL LAPSES...MORE SO
ACROSS NORTHERN WI.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 607 PM CDT MON SEP 7 2015
SATELLITE AND SURFACE OBSERVATIONS INDICATE THE MVFR DECK HAS
BEEN BREAKING UP AND THE FORECAST SOUNDINGS FROM THE 07.18Z NAM DO
NOT SUGGEST IT WILL REFORM UNTIL LATER TONIGHT. PLAN TO START BOTH
SITES WITH VFR CONDITIONS AND HOLD THESE THROUGH THE NIGHT. THE
BIG QUESTION THEN BECOMES HOW FAR NORTH CONVECTION WILL GET
OVERNIGHT. AS A SHORT WAVE TROUGH LIFTS NORTHEAST OUT OF THE
PLAINS AND THE LOW LEVEL JET IMPINGES ON THE BOUNDARY ACROSS
IOWA...SHOWERS AND STORMS WILL DEVELOP AND THEN MOVE
EAST/NORTHEAST. THE 07.21Z HRRR AND 07.12Z HI-RES NMM ARE THE MOST
AGGRESSIVE IN LIFTING THIS ACTIVITY TO THE NORTH AND BRING THIS
INTO THE TAF SITES BETWEEN 08.06Z AND 08.09Z. THE OTHER HI-RES
MODELS SUGGEST MOST OF THE ACTIVITY WILL STAY TO THE SOUTH OF THE
AREA WITH MAYBE JUST SOME GENERAL SHOWERS MOVING THROUGH VERY LATE
TONIGHT INTO TUESDAY MORNING. FOR NOW WILL STAY WITH THE TRENDS
FROM THE PREVIOUS FORECAST BUT DELAY THE ONSET OF THE VCSH AND
PREVAILING SHOWERS JUST A LITTLE BIT. AS THE CONVECTION DEVELOPS
THIS EVENING...SHOULD BE ABLE TO GET A BETTER HANDLE ON HOW FAR
NORTH IT WILL BE AND CAN MAKE ADJUSTMENTS WITH LATER FORECASTS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...04
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
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 TUCSON AZ
240 AM MST TUE SEP 8 2015
.SYNOPSIS...SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS TODAY THROUGH WEDNESDAY. A DRYING TREND WILL LIKELY
BEGIN THURSDAY...WITH SHOWERS AND THUNDERSTORMS CONFINED TO MAINLY
NEAR THE EASTERN MOUNTAINS THIS WEEKEND. NEAR NORMAL HIGH
TEMPERATURES WILL OCCUR EXCEPT FOR SOME COOLING WEDNESDAY AND
THURSDAY.
&&
.DISCUSSION...SW FLOW ALOFT OVER THE AREA THIS AM WITH SCATTERED
MAINLY MID TO HIGH LEVEL CLOUDS. RADAR HAS BEEN DETECTING SOME LIGHT
SHOWERS/SPRINKLES W AND NW OF TUCSON...WHICH MOST LIKELY IS NOT
MAKING IT TO THE GROUND. LATEST HRRR RUNS KEEP ISOLATED LIGHT
SHOWERS/SPRINKLES ACROSS ERN PINAL/NRN GRAHAM THIS MORNING.
LAST NIGHTS UPPER AIR PLOTS PLACED THE UPPER HIGH OVER TEXAS BIG
BEND WITH AXIS EXTENDING WEST ACROSS NRN SONORA/BAJA. WATER VAPOR
SHOWED A WEAK UPPER LEVEL TROF OVER NW AZ WHICH IS PROGGED TO MOVE E
TODAY. PRECIPITABLE WATER REMAINS RATHER HIGH ACROSS THE AREA FOR
EARLY SEPTEMBER WITH VALUES MOSTLY IN THE 1.25"-1.70" RANGE HIGHEST
OUT WEST. PW VALUES THROUGHOUT THE GULF OF CA RANGED FROM 2" IN THE
NORTH TO 2.50" AT THE MOUTH AS SELY WINDS ARE STARTING TO INCREASE
THANKS TO HRCN LINDA. SO THE GLFCA IS ALREADY FLOODED WITH MOISTURE.
FOR TODAY...AS THE UPPER HIGH OVER THE TEXAS BIG BEND MOVES INTO NRN
CHIHUAHUA...THE ORIENTATION OF THE ASSOCIATED RIDGE AXIS LIFTING NE
INTO SRN CA FROM NRN BAJA. THE NAM IS SUGGESTING THAT A PIECE OF
ENERGY ON THE NE FLANK OF HRCN LINDA MAY PUSH N ACROSS SONORA MX
TODAY PROVIDING THE UPPER LEVEL SUPPORT FOR POSSIBLE MCS JUST S OF
THE INTNL BORDER. GFS/EC ALONG WITH UOFA WRF RUNS OF NAM/GFS NOT HOT
ON THIS IDEA. SO FOR NOW WILL GO WITH A LOW GRADE MONSOON FORECAST
WITH EMPHASIS ON THE BORDER LOCALS...ESPECIALLY SANTA CRUZ COUNTY.
HOWEVER CONFIDENCE IS LOW ESPECIALLY LATER THIS AFTERNOON INTO THIS
EVENING.
WEDNESDAY...HIGHER PW VALUES FROM THE GULF OF CALIFORNIA IS PUSHED
INTO THE LOWER DESERTS WITH 2+" VALUES OVER WRN PIMA COUNTY. THE BIG
QUESTION FOR WEDNESDAY WILL BE AMOUNT OF SUN THE AREA WILL GET.
RIGHT NOW LOOKS LIKE A LOT OF CLOUDS BEING AROUND WITH SCATTERED
SHOWERS AND ISOLATED EMBEDDED BOOMERS WITH THE BEST CHANCES FOR
STORMS BEING WEST AND SOUTH OF TUCSON.
MAIN THREAT FOR STORMS LATER TODAY AND WEDNESDAY WILL BE LOCALIZED
HEAVY RAINERS ALONG WITH FLASH FLOODING CONCERNS.
THURSDAY...BATTLE GROUND DAY AS NORTHERLY FLOW STARTS TO PUSH INTO
THE NRN AREAS WHILE IT REMAINS VERY MOIST ACROSS SOUTHERN SECTIONS.
AT THIS TIME WILL RIDE THE INHERITED SLIGHT CHANCE TO LOW END CHANCE
TYPE POPS.
FRIDAY INTO SUNDAY...DRIER NORTHERLY FLOW OVER THE AREAS WILL BRING
ABOUT A MARKED DECREASE IN THUNDERSTORM ACTIVITY...MAINLY ACROSS THE
ERN MOUNTAINS.
EARLY NEXT WEEK...MAY SEE A SLIGHT UPTICK IN STORM COVERAGE AS FLOW
ALOFT BECOME A BIT MORE SOUTHERLY.
HIGH TEMPERATURES FOR THE MAJORITY OF THIS FORECAST PACKAGE WILL BE
NEAR NORMAL...WITH THE EXCEPTION BEING WEDNESDAY AND THURSDAY.
&&
.AVIATION...VALID THRU 09/12Z.
FEW-SCT CLOUDS AT 12-16K FT AGL AND SCT-BKN CLOUDS AOA 20K FT AGL
THRU 08/21Z. AFT 08/21Z...SCT-BKN CLOUDS AT 8-12K FT AGL AND BKN-OVC
CLOUDS AOA 15K FT AGL. SLIGHT CHANCE -SHRA/-TSRA THRU 08/21Z...THEN
SCT SHRA/TSRA. BRIEF MVFR CONDITIONS AND WIND GUSTS OF 30-40 KTS
WILL OCCUR WITH THE STRONGER TSRA. OTHERWISE...SURFACE WIND LESS
THAN 10 KTS THRU THE FORECAST PERIOD. PARTIAL CLEARING LATE TONIGHT
AND DURING THE OVERNIGHT HOURS. AVIATION DISCUSSION NOT UPDATED FOR
TAF AMENDMENTS.
&&
.FIRE WEATHER...THERE WILL BE A CHANCE OF MAINLY AFTERNOON AND
EVENING SHOWERS AND THUNDERSTORMS THROUGH THURSDAY. BY LATE THIS
WEEK AND OVER THE UPCOMING WEEKEND...MUCH LESS SHOWER/THUNDERSTORM
ACTIVITY IS EXPECTED...WITH ANY CONVECTION CONFINED TO THE HIGHER
TERRAIN ALONG THE NEW MEXICO BORDER. STRONG...GUSTY AND ERRATIC
WINDS WILL OCCUR WITH THE STRONGER THUNDERSTORMS. OTHERWISE... 20-
FOOT WINDS WILL BE MAINLY TERRAIN DRIVEN AND LESS THAN 15 MPH.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1155 PM CDT MON SEP 7 2015
.UPDATE...
ISSUED AT 944 PM CDT MON SEP 7 2015
AT THE PRESENT TIME I DID NOT MAKE LARGE SCALE CHANGES TO THE
GOING FORECAST HOWEVER...THE LATEST HRRR IS SUGGESTING THAT THE
HEAVY RAINFALL WOULD BE FOCUSED MORE ACROSS NORTHERN IOWA. ONGOING
STORMS ACROSS NEBRASKA/KANSAS HAS BEEN FIZZLING AS THEY CROSS INTO
IOWA. IT APPEARS THESE STORMS HAVE FIRED ALONG AN INSTABILITY AXIS
WHERE MOISTURE TRANSPORT AS BEEN PRETTY GOOD. AS A LOW LEVEL JET
DEVELOPS I STILL EXPECT STORMS TO EVENTUALLY WORK ACROSS SOUTHERN
IOWA OVERNIGHT AND GIVEN THE HEAVY RAINFALL WE RECEIVED LAST NIGHT
IT WON`T TAKE MUCH TO PRODUCE FLASH FLOODING. HOWEVER...A SURFACE WARM
FRONT IS SITUATED ACROSS NORTHERN IOWA AND THERE IS AN APPROACHING
SHORTWAVE COMING ACROSS CEN NEB/SOUTH DAKOTA WHICH SHOULD BE
MOVING INTO NORTHERN IOWA OVERNIGHT. CONVECTION HAS BEEN RATHER
ROBUST IN THIS AREA THIS EVENING. MOISTURE TRANSPORT HAS INCREASED
INTO THIS AREA AND ONCE A SW LOW LEVEL JET GETS GOING CONVECTION
SHOULD INCREASE IN THIS AREA AND OVERSPREAD NORTHERN IOWA. THE
HRRR HAS LATCHED ONTO THIS IDEA AND IT CERTAINLY APPEARS
REASONABLE TO ME. I HAVE INCREASED POPS AND QPF FOR NOW BUT WOULD
NOT BE SURPRISED TO SEE THE HEAVY RAIN AREA SHIFTED FURTHER NORTH.
WILL BE WATCHING THE EVOLUTION OF THIS WITH TIME BUT FOR NOW I`M
BECOMING INCREASINGLY CONCERNED ABOUT NORTHERN IOWA.
&&
.SHORT TERM /TONIGHT/...
ISSUED AT 327 PM CDT MON SEP 7 2015
HEAVY RAIN REMAINS THE CONCERN OF THE OVERNIGHT FORECAST.
OVERNIGHT CONVECTION HAS LAID OUT AN OUTFLOW BOUNDARY OVER
NORTHERN MISSOURI WHICH IS TIED BACK INTO THE LOW OVER KANSAS.
THE SYNOPTIC BOUNDARY IS STILL OVER IOWA...STRETCHING FROM NEAR
PRAIRIE DU CHIEN BACK WEST TO NEAR DENISON. H850 FRONT IS ALSO
SITUATED OVER IOWA NOW. THE MODELS ARE HAVING DIFFICULTY WITH THE
EVOLUTION OF THE CONVECTION TONIGHT...BUT AN OVERALL CONSENSUS IS
FOR THE CENTRAL AND SOUTH TO RECEIVE THE BALANCE OF THE FORCING
AND THUS...RAINFALL. THE NAM WAS FARTHER SOUTH WITH THE MAIN QPF
AXIS TONIGHT...WHILE THE GFS LOOKS VERY SIMILAR TO LAST NIGHTS
FARTHER NORTH PLACEMENT OVER IOWA...THIS TIME RIGHT OVER THE I80
CORRIDOR. THE OTHER MESO MODELS SHOW A VARIETY OF SOLUTIONS...WITH
THE HIRES ARW HAVING A FOCUS FOR TWO AREAS OF HEAVY RAINFALL...ONE
NEARER THE IA/MO BORDER AND ONE ALONG THE I80 CORRIDOR. THE LATEST
HRRR RUN IS SHOWING TWO MAXIMA AS WELL...WITH A LESS ORGANIZED
CLUSTERING THAN THE OTHER MODELS MENTIONED. A NUMBER OF FACTORS
ARE POINTING TOWARD TWO MAXIMA...ONE THE H850 BOUNDARY IS ALREADY
BECOMING ACTIVE OVER CENTRAL NEBRASKA AND THERE IS ALSO SOME
DEVELOPMENT ALONG THE TRIPLE POINT IN SOUTHEAST NEBRASKA NEARER
THE SFC LOW...COOL FRONT...AND OUTFLOW BOUNDARY INTERSECTION. THE
SOUTHERN CLUSTER WILL FOLLOW THE BOUNDARY UNTIL IT IS LIFTED NORTH
THIS EVENING...WHILE THE NORTHERN AREA WILL CONTINUE TO FILL IN
THROUGH THE EVENING HOURS. AS THE LOW LEVEL JET KICKS IN BETWEEN
02-03Z THIS EVENING...THE COVERAGE AND INTENSITY OF THE CONVECTION
SHOULD INCREASE. NOTHING MUCH HAS CHANGED WITH REGARD TO THE
AVAILABLE MOISTURE...STILL RUNNING ABOUT 2.30 INCH PWATS AT 06Z
OVER THE SOUTH THIRD WITH WARM CLOUD DEPTHS PUSHING 13.8 KFT AT
OVERNIGHT. THE SCENARIO IS PRETTY MUCH THE SAME FOR EFFICIENT
RAINFALL PROCESSES TONIGHT...SO HAVE GENERALLY GONE ABOUT 1 TO 2
INCHES ACROSS THE SOUTH WITH THE EXPECTATION THAT THERE MAY BE
SOME TOTALS IN THE 4 TO 5 INCH RANGE BY MORNING. AS THE LOW
PUNCHES NORTH THIS EVENING...LOWS WILL REMAIN WARM SOUTH/SOUTHEAST
WITH SLIGHTLY COOLER NORTHWEST. SHOWERS WILL HOLD ON IN THE
SOUTHEAST. WITH LIGHT WINDS IN THE MORNING...PATCHY TO AREAS OF
FOG MAY ALSO DEVELOP.
.LONG TERM /TUESDAY THROUGH MONDAY/...
ISSUED AT 327 PM CDT MON SEP 7 2015
THE LONG TERM FORECAST GROWS GENERALLY MORE AUTUMNAL AS A SERIES
OF NORTHERN STREAM MID/UPPER LEVEL TROUGHS ROUNDING BROAD CYCLONIC
FLOW KEEP THE MORE SUMMERLIKE WEATHER BENEATH A LARGE RIDGE
SHUNTED OFF TO OUR SOUTH AND WEST. THE FIRST OF THESE TROUGHS WILL
MOVE OVERHEAD ON TUESDAY...POSSIBLY GENERATING SOME ELEVATED
SHOWERS AND THUNDERSTORMS MAINLY ACROSS THE SOUTHERN HALF OF THE
FORECAST AREA. HOWEVER...THE SURFACE FRONT SHOULD BE BLOWN THROUGH
INTO MISSOURI BY TONIGHTS CONVECTION AND ANY SEVERE WEATHER OR
HEAVY RAIN THREAT WILL BE SOMEWHAT DIMINISHED TOMORROW. THIS
INITIAL TROUGH WILL ALSO FINALLY SCOUR OUT OUR WARM AND JUICY
AIRMASS OUT OF IOWA...WITH A COOL AREA OF HIGH PRESSURE BRINGING
DRY AND PLEASANT WEATHER BY WEDNESDAY.
THE SECOND...SUBSTANTIALLY STRONGER MID/UPPER LEVEL TROUGH WILL
DEEPEN AS IT MOVES OVER MINNESOTA AND WISCONSIN AROUND THURSDAY
NIGHT AND FRIDAY. THIS WILL PUSH A MORE PRONOUNCED REINFORCING
COLD FRONT ACROSS IOWA DURING THIS TIME FRAME...BRINGING
CONSIDERABLY COOLER WEATHER FROM FRIDAY INTO SATURDAY. THE PASSAGE
OF THE FRONT WILL LIKELY GENERATE ISOLATED TO SCATTERED SHOWERS
AND THUNDERSTORMS AROUND THURSDAY NIGHT...BUT TIMING DIFFERENCES
AMONG THE MODELS PROHIBIT GOING HIGHER THAN 20 OR 30 POPS AT THIS
TIME. WHILE THE FORCING AND WIND FIELDS ASSOCIATED WITH THE
PASSAGE OF THIS SYSTEM MAY BE ROBUST...INSTABILITY SHOULD BE
LIMITED MITIGATING ANY SEVERE WEATHER THREAT. THE ALTERNATING
PATTERN OF TROUGHS AND RIDGES WILL CONTINUE FROM THE WEEKEND INTO
NEXT WEEK WITH SUNSHINE AND RECOVERING TEMPERATURES ON SUNDAY
FOLLOWED BY ANOTHER COLD FRONT ON MONDAY OR MONDAY NIGHT...AND
POSSIBLY ANOTHER AROUND WEDNESDAY OR THURSDAY OF NEXT WEEK THOUGH
THAT IS BEYOND THE SEVEN DAY FORECAST PERIOD.
OUTSIDE OF SOME LINGERING POTENTIAL FOR STRONG STORMS OR HEAVY
RAIN ON TUESDAY...WHICH SHOULD BE AN ISOLATED THREAT...AND THE
LOW POSSIBILITY OF PERHAPS A COUPLE OF BRIEFLY STRONG STORMS WITH
THE FRONT AROUND THURSDAY NIGHT...THERE IS LITTLE IN THE WAY OF
HAZARDOUS OR HEADLINE INDUCING WEATHER DURING THE NEXT SEVEN DAYS.
OVERALL IT WILL BE COOLER...DRY...AND STARTING TO FEEL LIKE FALL
ACROSS IOWA.
&&
.AVIATION...08/06Z
ISSUED AT 1155 PM CDT MON SEP 7 2015
COMPLICATED FORECAST WITH A STALLED BOUNDARY ACROSS CENTRAL IOWA AND
AN APPROACHING SHORTWAVE WITH AN INCREASING LOW LEVEL JET. MAIN
AREA OF CONVECTION WILL BE STORMS BLOSSOMING ACROSS NEBRASKA PUSHING
INTO TAF LOCATIONS LATE TONIGHT...08Z-12Z. A SECOND AREA OF
CONVECTION OVER FSD AREA WILL MOVE ACROSS NORTHERN IOWA. ALTHOUGH
HEAVY RAIN IS POSSIBLE ANYWHERE ACROSS IOWA THE BETTER POTENTIAL
WILL REMAIN ACROSS THE SOUTHERN IOWA. MVFR WITH LCL IFR CONDITIONS
WILL PERSIST THROUGH 12Z-15Z WITH SLOW IMPROVEMENT NW TO SE. SFC
FLOW WILL BE EAST TO SOUTHEAST THEN BECOME NORTHERLY.
&&
.HYDROLOGY...
ISSUED AT 327 PM CDT MON SEP 7 2015
EVEN WITH THE RESPITE IN RAIN TODAY...WE STILL REMAIN PRIMED FOR
ADDITIONAL RISES IN RIVERS OVER THE NEXT SEVERAL DAYS.
LAST NIGHTS EXTREME RAINS WERE FAIRLY LOCALIZED IN THE RACCOON RIVER
BASIN AND WITH ADDITIONAL RAINFALL TONIGHT...SOME LOCATIONS MAY
REACH MODERATE CATEGORY ACROSS CENTRAL IOWA. CONFIDENCE ON TONIGHTS
RAINFALL IS SOMEWHAT LIMITED DUE TO LAST NIGHTS CONVECTION AND THE
EXPECTED RECOVERY OF STORMS LATER TONIGHT FARTHER WEST IN NEBRASKA.
IF THE STORMS FOLLOW A SIMILAR EVOLUTION TO LAST NIGHT...THE RACCOON
RIVER WOULD BE FURTHER AFFECTED...ALONG WITH SOME IMPACTS FOR
STREAMS AND CREEKS OVER CENTRAL AND SOUTHERN IOWA...LEADING TO
LOCALIZED FLASH FLOODING OVERNIGHT AND ADDITIONAL RISES TO MAIN STEM
RIVERS AND POSSIBLE RIVER FLOOD WARNINGS IN THE NEXT FEW DAYS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 7 AM CDT TUESDAY FOR ADAIR-ADAMS-
APPANOOSE-AUDUBON-BOONE-CARROLL-CASS-CLARKE-CRAWFORD-DALLAS-
DAVIS-DECATUR-GREENE-GUTHRIE-JASPER-LUCAS-MADISON-MAHASKA-MARION-
MARSHALL-MONROE-POLK-POWESHIEK-RINGGOLD-STORY-TAMA-TAYLOR-UNION-
WAPELLO-WARREN-WAYNE.
&&
$$
UPDATE...FAB
SHORT TERM...REV
LONG TERM...LEE
AVIATION...FAB
HYDROLOGY...REV
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1134 PM MDT MON SEP 7 2015
.UPDATE...
ISSUED AT 526 PM MDT MON SEP 7 2015
WITH MAIN AREA OF THUNDERSTORMS AHEAD OF FRONTAL ZONE TO THE SOUTH
OF THE AREA AND ATTEMPTS AT CONVECTION FADING ACROSS EXTREME
SOUTHWEST CWA HAVE REFINED POPS AND WX TO MORE CLOSELY FOLLOW
DEVELOPING LINE OF CONVECTION ACROSS NORTHEAST COLORADO ALONG
ROBUST COLD POOL. STARTING TO SEE SIGNIFICANT WIND GUSTS TO AROUND
45 MPH WITH THIS FEATURE AND THINK THAT WILL CONTINUE FOR NEXT 2
HOURS. WITH STRONGER CAP ACROSS THE EASTERN CWA NOT SURE HOW FAR
LINE WILL MAKE IT...SO HAVE BEEN SOMEWHAT PESSIMISTIC ABOUT
CHANCES ACROSS EASTERN HALF OF AREA.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH TUESDAY)
ISSUED AT 143 PM MDT MON SEP 7 2015
EARLY AFTERNOON WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOWS SW
FLOW IN PLACE ACROSS CENTRAL ROCKIES OVER OUR CWA...AND INTO THE
NORTHERN PLAINS. THIS IS AHEAD OF LARGE UPPER LOW CENTERED OVER
CENTRAL CANADA WITH BROAD TROUGHING EXTENDING SOUTH ACROSS THE
PACIFIC NORTHWEST. CHECKING DYNAMIC TROPOPAUSE...EMBEDDED WEAK
SHORTWAVE TROUGH THAT ROTATED THROUGH REGION THIS MORNING IS NOW
OVER NORTHCENTRAL KS WITH A STRONGER PV HEIGHT ANOMALY ENTERING
CENTRAL COLORADO. SUBSIDENCE BEHIND THE INITIAL FEATURE IS STILL
TRANSITIONING ACROSS MOSTLY OF OUR CWA. AT THE SURFACE A STALLED
FRONT IS JUST SOUTH OF INTERSTATE 70 WITH SURFACE LOW EXTENDING
FROM SOUTHERN COLORADO ACROSS SW KS AND INTO NW KANSAS.
THIS AFTERNOON-TUESDAY...FORCING IS EXPECTED TO INCREASE THIS
EVENING WITH NEXT SHORTWAVE TROUGH MOVING OUT OF THE CENTRAL ROCKIES
AND INTERACTING WITH STALLED FRONTAL ZONE OVER OUR CWA. THERE IS
THE POSSIBILITY FOR OVERRUNNING/BACKBUILDING ALONG ELEVATED FRONTAL
ZONE/STRENGTHENING H7 TROUGH AXIS AS THIS FEATURE MOVES ACROSS THE
REGION. EAST/NORTHEAST FLOW WILL CONTINUE TO ADVECTS BOUNTIFUL
MOISTURE OVER OUR CWA...WITH MODERATE INSTABILITY CONTINUING
THROUGH THE EVENING. CONFIDENCE IS LOWER REGARDING COVERAGE...WITH
FAIRLY LARGE SPREAD IN GUIDANCE SINCE OVERNIGHT AND SUBSIDENCE
INITIALLY IN PLACE OVER OUR CWA. CURRENT ARW/NMM DEPICTS ACTIVITY
INITIATING WEST OF OUR CWA...OR OVER OUR WESTERN CWA AROUND 00Z AND
TRACKING ALONG/NORTH OF FRONT THIS EVENING/OVERNIGHT BEFORE SLOWLY
TRANSITIONING EAST. HRRR/RAP BOTH SUPPORT A SIMILAR LOCATION AND
TIMING...HOWEVER SHOW MUCH LESS IN THE WAY OF COVERAGE. I FELT
COMFORTABLE ADJUSTING THE TIMING TO FAVOR THIS EVENING FOR BEST
COVERAGE AND KEPT MENTION LIMITED TO CHANCE FOR NOW. GUIDANCE SHOWS
BAROCLINIC ZONE LINGERING THROUGH EARLY AFTERNOON TUESDAY ACROSS OUR
SOUTHEAST WITH ADDITIONAL SHOWER/THUNDERSTORM DEVELOPMENT POSSIBLE.
I SHOWED GRADUAL TRANSITION TO THE EAST/SOUTHEAST IN LINE WITH
MODEL CONSENSUS.
REGARDING SEVERE THREAT...HIGH LOW LEVEL MIXING RATIOS HAVE AIDED IN
MODERATE INSTABILITY BUILDING ACROSS OUR CWA WITH ML CAPE 1500-2500
J/KG DEPICTED ON RAP ANALYSIS. DEEP UNIDIRECTIONAL FLOW HAS LED TO
HIGH SHEAR IN MID TO UPPER LEVELS WITH EFFECTIVE SHEER VALUES
ALREADY IN EXCESS OF 50KT OVER OUR CWA. BEST LOW LEVEL SHEAR IS
OVER NORTH CENTRAL KS/NEAR HILL CITY ASSOCIATED WITH VEERING NEAR
WHERE CLOSED SURFACE LOW MAY BE DEVELOPING BASED ON WIND/PRESSURE
FIELD. SEVERE THREAT SHOULD PREDOMINANTLY BE CONFINED TO LARGE
HAIL/DAMAGING WINDS...HOWEVER LOCATIONS IN THE FAR EASTERN PART OF
OUR CWA COULD SEE FAVORABLE CONDITIONS FOR SUPERCELL DEVELOPMENT
AND TORNADO RISK. WINDOW FOR THIS SHOULD BE CONFINED TO THIS
AFTERNOON/EARLY EVENING WITH FRONT TRANSITIONING BACK TO THE
SOUTHEAST THIS EVENING.
RAP/HRRR/NAM/SREF CONTINUE TO SHOW STRATUS/FOG REDEVELOPING ACROSS
NEBRASKA AND ADVECTING/SPREADING SOUTHWEST ACROSS OUR CWA. LOWEST
VIS COULD APPROACH DENSE FOG ADVISORY CRITERIA...THOUGH IT DOES
APPEAR TO BE FAIRLY TRANSIENT REGARDING LOWEST VISIBILITIES. FOR NOW
I KEPT AREAS OF FOG MENTION...AND WILL ALLOW SUBSEQUENT SHIFTS TO
MONITOR NEED FOR NEW DENSE FOG ADVISORY.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 230 PM MDT MON SEP 7 2015
THE WESTERLY FLOW ALOFT ACROSS THE CENTRAL HIGH PLAINS TURNS NORTHWESTERLY
BY THURSDAY AND MORE NORTHERLY BY FRIDAY AND SATURDAY AS THE HIGH
PRESSURE AREA ALOFT OVER NORTHERN MEXICO RETROGRADES AND MERGES
WITH THE HIGH IN THE EASTERN PACIFIC TO FORM A RIDGE OVER THE
WESTERN UNITED STATES WHILE SHORT WAVES EMBEDDED IN THE UPPER
FLOW MOVE THROUGH THE CENTRAL HIGH PLAINS AND INTO THE BASE OF THE
TROUGH DEEPENING IN THE MISSISSIPPI VALLEY REGION. EXPECT ISOLATED
TO SCATTERED SHOWERS AND THUNDERSTORMS FROM WEDNESDAY NIGHT
THROUGH FRIDAY NIGHT AS A RESULT OF THESE DISTURBANCES MOVING
ACROSS THE REGION WITH THE SURFACE FRONTAL BOUNDARY REMAINING
STALLED IN THE VICINITY OF THE FORECAST AREA THROUGH THE END OF
THE WEEK. EXPECT DAYTIME HIGHS MAINLY IN THE 80S WITH LOWS MAINLY
IN THE 50S THROUGH THIS PERIOD.
SOMEWHAT COOLER TEMPERATURES ARE EXPECTED ON FRIDAY AND SATURDAY
WITH DRY CONDITIONS SATURDAY AND SUNDAY IN THE WAKE OF THE
STRONGER SHORT WAVE TROUGH ALOFT AND THE HIGH PRESSURE AREA TO
FOLLOW A COLD FRONT ACROSS THE REGION. SURFACE HIGH PRESSURE MOVES
OUT OF THE FORECAST ARE ON SUNDAY WITH THE LEE TROUGH DEVELOPING
AND TEMPERATURES WARMING AGAIN WITH SOUTHWEST SURFACE FLOW AND THE
WEAKENING RIDGE ALOFT OVER SOUTHWEST U.S. EXTENDING INTO THE
CENTRAL HIGH PLAINS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1130 PM MDT MON SEP 7 2015
ELEVATED THUNDERSTORMS STARTING TO DEVELOP IN RESPONSE TO NEARBY
UPPER LEVEL TROUGH...EXPECT SPOTTY COVERAGE NEAR TAF SITES AND
OVERALL AVIATION IMPACT TO BE LIMITED. OTHER CONCERN WILL BE
POTENTIAL FOR MORNING STRATUS...PRIMARILY AT MCK. LATEST MODELS
HAVE BACKED OFF OF COVERAGE AND CURRENT LIGHT VARIABLE WIND FIELD
NOT REALLY SHOWING A STRONG SIGN OF ADVECTION. HOWEVER...SAT FOG
PRODUCT SHOWING AN INCREASING AREA OF LOW CLOUDS AND THINK
REASONABLY HIGH THREAT FOR PERIOD OF IFR CIGS AT MCK. HAVE
DELAYED TIMING TILL CLOSER TO 12Z...BUT IF CIRRUS SHIELD WERE TO
THIN COULD SEE A QUICKER ONSET DUE TO STRONGER COOLING.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JRM
SHORT TERM...DR
LONG TERM...LOCKHART
AVIATION...JRM
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1220 AM CDT TUE SEP 8 2015
.UPDATE...
ISSUED AT 636 PM CDT MON SEP 7 2015
The environment across the forecast area continues to evolve this
evening, and have adjusted the severe thunderstorm watch
accordingly. First off, northeast Kansas appears to have
stabilized substantially, and while there is a westerly advection
component of the more unstable central KS air, limited daytime
heating should keep the severe potential quite low in northeast
KS. Should note that ample shear remains in place, so any elevated
storms that can recognized this shear would pose a short lived
severe threat.
Central and east central KS remain quite unstable, with perhaps
the greatest instability into east central Kansas where Emporia
has a temperature of 88 with a dewpoint of 73 at last hour, likely
resulting in surface based CAPE well over 2000 J/Kg. Meanwhile,
effective shear at or greater than 40 kts has overspread the area.
This has fueled recent supercell development in Marion county and
could sustain the severe threat across the rest of east central KS
as well...although again the instability decreases into far
eastern KS. An outflow boundary near/just north of Emporia may
serve as a focus for severe storm development with very large
hail, damaging winds, and a small but non-zero threat for
tornadoes. Severe threat should wane after 9 PM.
&&
...Update to aviation forecast discussion...
.SHORT TERM...(THIS EVENING THROUGH Tuesday)
ISSUED AT 402 PM CDT MON SEP 7 2015
Showers and isolated storms continued off and on through the
afternoon hours in a zone of 1000-900mb convergence, weak isentropic
lift and the presence of a weak wave. Although the bulk of the
precipitation has moved east into missouri expect isolated to
scattered showers to continue across east central Kansas into the
early evening hours. Further north near the Nebraska border where
few clouds have allowed temperatures to warm into the lower to mid
90s. Latest mesoanalysis shows about 40 to 50kts of effective
shear, 1500-3000 J/kg of CAPE and no cap in place. Isolated
thunderstorms have developed just to the northwest of the forecast
area and were moving northeast across southern Nebraska at 1930Z.
Latest runs of the HRRR and the RAP suggest further development
across north central Kansas into the evening hours, with
additional development from central Kansas across northeast Kansas
through the evening hours. Storms that can develop across the
northern counties may be severe with hail, strong winds and an
isolated tornado possible. Another round of storms is expected
overnight into Tuesday morning as the upper level trough
progresses eastward across the Northern and Central Plains. Good
moisture transport is expected into northeast Kansas overnight
with precipitable water around 2 inches which will increase the
potential for locally heavy rainfall. The front is expected to
move slowly southeast across the forecast area on Tuesday then
moving out of east central Kansas Tuesday evening. Showers and
thunderstorms will likely be ongoing in the morning hours and then
continue along the boundary in the afternoon.
Clouds south of I-70 have kept temperatures in check in the upper
70s to upper 80s. Will likely still see some fluctuations in
temperatures through the late afternoon where the sun can come out.
Tonight, lows should cool into the low to mid 70s with highs on
Tuesday only in the low to mid 80s.
.LONG TERM...(Tuesday NIGHT THROUGH Monday)
ISSUED AT 402 PM CDT MON SEP 7 2015
Cold front and associated showers and thunderstorms should be
moving to the southeast out of east central KS Tuesday evening.
Then surface high pressure builds in with pleasant temperatures
and lower humidities for Wednesday and Wednesday night.
Northwest flow aloft then sets up through the end of the week
with the first in a series of disturbances possibly affecting
north central KS by late Thursday afternoon. That system moves
through Thursday night through Friday with a good chance of
thunderstorms during this time.
Subsidence behind the trough and associated surface high pressure
builds in for Saturday, and an upper ridge builds eastward for
Sunday and Monday, keeping the weekend into Monday dry.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z Tuesday NIGHT)
ISSUED AT 1219 AM CDT TUE SEP 8 2015
Will keep vcts through the overnight hours as showers/storms still
popping up occasionally. Added a tempo for best timing of storms
to form along the front as it moves through the terminals late
morning. May have mvfr cigs behind the boundary but at this time
is advertised to clear out rather fast with the wind shift.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Barjenbruch
SHORT TERM...53
LONG TERM...GDP
AVIATION...67
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
340 AM EDT TUE SEP 8 2015
.SHORT TERM...TODAY AND TONIGHT
ABSENT FORCING, THE RESERVOIR OF SIGNIFICANT MOISTURE ABOVE 700MB ON
LAST NIGHT`S 00Z DTX SOUNDING REMAINED QUIET THROUGH ABOUT 06Z.
HOWEVER, WARM ADVECTION WITHIN STRENGTHENING SWLY FLOW BEGAN TO
IGNITE CONVECTION ROUGHLY ALONG A CHICAGO TO PORT HURON LINE BY 07Z.
CONDITIONS WILL REMAIN FAVORABLE FOR EXPANSION OF THIS ACTIVITY
THROUGH THE MORNING AS FLOW CONTINUES TO INCREASE AND DAYTIME
HEATING ADDS A FEW HUNDRED J/KG CAPE TO THE PROFILE. THROUGH 18Z,
CONVECTION IS EXPECTED TO BE CONFINED MAINLY NORTH OF M59 ALONG WITH
THE BETTER FORCING. PWATS AROUND 2", LOW DENSITY CAPE, AND AN
INCREASINGLY DEEP WARM CLOUD LAYER WILL SUPPORT A HEAVY RAIN THREAT
FOR ANY AREAS THAT RECEIVE RAIN THROUGH TONIGHT. LOCALIZED FLOODING
IS NOT OUT OF THE QUESTION GIVEN SLOWER STORM MOTION AND THE
POTENTIAL FOR SOME AREAS ACROSS THE NORTHWEST TO SEE MULTIPLE ROUNDS
OF RAINFALL.
A SECOND AND STRONGER LLJ SURGE WILL ARRIVE BY AFTERNOON IN ADVANCE
OF THE SHORTWAVE NOTED OVER NORTHWEST MISSOURI AT 07Z THIS MORNING.
DYNAMIC FORCING WILL BE STOUT, BUT WILL ONLY OCCUR OVER A RELATIVELY
SMALL SPATIAL FOOTPRINT, MOST OF WHICH WILL BE OVER WESTERN AND
NORTHERN LOWER. HOWEVER, 06Z RAP INDICATES THAT THE CORE OF THE
ASSOCIATED 35-40KT LLJ WILL ALIGN ALONG A MUSKEGON TO WEST BRANCH
LINE 21-00Z WHICH WILL PUT THE SAGINAW VALLEY IN LINE TO RECEIVE A
NOTEWORTHY BOOST IN FORCING DUE TO DIFFERENTIAL WARM ADVECTION LATE
IN THE PEAK HEATING PERIOD. THUS, EVEN IF THE STRONGER DYNAMIC
FORCING DOES MANAGE TO MISS THE CWA...AND AT THIS TIME IT`S PROGGED
TO JUST GRAZE THE SAGINAW VALLEY AREA...NORTHWESTERN AREAS SHOULD
STILL SEE SOME EASTWARD EXPANSION OF CONVECTION DURING THE MID TO
LATE AFTERNOON DUE TO THE STRENGTHENING LLJ.
THE BULK OF THE RAIN SHIELD WILL EVENTUALLY PEEL NORTH ALONG WITH
THE DEPARTING WAVE, BUT LARGER SCALE FORCING EMBEDDED WITHIN THE
RIGHT ENTRANCE OF A 130KT UPPER JET OVER LAKE SUPERIOR WILL SUPPORT
A WAVE OF SHOWERS SLOWLY TRAVERSING THE REMAINDER OF THE AREA
ROUGHLY 00Z-12Z WED. THESE, TOO, WILL CARRY THE SAME THREAT FOR
HEAVY RAIN, THOUGH A DIMINISHED THREAT FOR FLOODING WILL EXIST DUE
TO INCREASINGLY PROGRESSIVE LARGER SCALE FORCING.
&&
.LONG TERM...
A STRONG WAVE ENTERING THE BASE OF THE MID/UPPER LEVEL TROUGH
CENTERED OVER WESTERN ONTARIO WILL PROVIDE THE NEEDED BOOST TO
USHER THE LINGERING FRONTAL BOUNDARY OFF TO THE EAST WEDNESDAY.
TIMING IS STILL NOT IRONED OUT EXACTLY AS THE INCOMING WESTERLY
JET MAX TURNS MORE NORTHEASTERLY ONCE IT PHASES WITH THE EXISTING
JET ALIGNED WITH THE FRONT. SO EXPECT THE FRONT TO BECOME MORE
PROGRESSIVE AS THE PARENT SYSTEM GAINS SPEED...BUT WITH THE SE
RIDGE STILL REACHING UP INTO THE EASTERN GREAT LAKES WE CAN EXPECT
SHOWERS TO LINGER OVER THE EASTERN COUNTIES INTO THE AFTERNOON
HOURS WEDNESDAY. THE FRONT WILL PUSH THE ENHANCED RIBBON OF
MOISTURE...NEAR 2 INCH PWATS...OFF TO THE EAST BY MIDDAY WEDNESDAY
BUT RESIDUAL MOISTURE POOL BETWEEN 1- 1.5 INCHES WILL STILL LINGER
THROUGH THE AFTERNOON UNTIL A SECONDARY TROUGH DROPS THROUGH LOWER
MI. THE NAM IS VERY BULLISH ON GENERATING SHOWERS WITH THIS
SECONDARY TROUGH IN PART DUE TO ELEVATED LL LAPSE RATES IN THE
WAKE OF THE FRONT. THERE IS SOME SIGNAL IN THE EURO/GFS BUT WITH
THE STRENGTH OF THE FRONTAL CIRCULATION...EXPECT A GOOD DEAL OF
SUBSIDENCE IN ITS WAKE COMBINED WITH THE BUILDING RIDGE. IN
ADDITION...THE NAM HAS BEEN DEVELOPING A SFC LOW ALONG THE FRONT
PASSING JUST TO OUR SOUTH THROUGH TOLEDO WEDNESDAY
AFTERNOON/EVENING. THIS WOULD RESULT IN ADDITIONAL DEFORMATION
FORCING LINGERING OVER SE MI AFTER 00Z THURSDAY. BUT AGAIN...NO
OTHER MODEL HAS ANYTHING NEARLY AS ORGANIZED AT THIS TIME.
SOMETHING TO WATCH BUT IN THE MEANTIME...FORECAST WILL FEATURE
CHANCE POPS DECREASING THROUGH THE DAY FROM NORTHWEST TO
SOUTHEAST.
WITH THE FRONT TO OUR SOUTH...PRECIP AND OVERCAST SKIES...HIGH
TEMPERATURES WILL TAKE A NOTABLE DIVE WEDNESDAY TOPPING OUT IN THE
UPPER 70S. THE SECONDARY TROUGH LATE WEDNESDAY WILL BRING ABOUT
COOLER WEATHER WITH NORTHERLY FLOW DROPPING HIGHS INTO THE MID 70S
FOR THURSDAY. TEMPS WILL TAKE A FURTHER NOSE DIVE INTO THE WEEKEND
AS YET ANOTHER FRONT SWEEPS THROUGH THE REGION ON FRIDAY BRINGING
THE NEXT CHANCE OF PRECIP WITH IT. MID MI MAY SEE SOME PRECIP
THURSDAY/THURSDAY NIGHT AS IT DRAPES SW TO NE THROUGH NORTHERN
LOWER...BUT MOST OF SE MI WILL REMAIN DRY TIL FRIDAY. MODELS DIVERGE
QUITE A BIT FOR THE WEEKEND IN THE HANDLING OF THIS NEXT UPPER
TROUGH...BUT CONSENSUS IS TROUGHING WILL HOLD OVER THE REGION WITH
ADDITIONAL SHOTS OF COOLER AIR WITH EACH FRONT. 850MB COLD POOL WILL
SET UP OVER THE GREAT LAKES WITH TEMPS POTENTIALLY DOWN INTO THE MID
SINGLE DIGITS AS HIGH PRESSURE SETTLES OVER THE REGION FROM CANADA.
&&
.MARINE...
A COLD FRONT DRAPED ACROSS THE CENTRAL GREAT LAKES IS RESULTING IN
WEAK FLOW WITHIN THE TROUGH OF LOW PRESSURE. THE EXCEPTION WOULD BE
LAKE ERIE AND LAKE ST CLAIR WHOM WILL CONTINUE TO RESIDE IN THE
SOUTHWESTERLY FLOW IN ADVANCE OF THE FRONT THROUGH THIS EVENING. THE
FRONT WILL BRING ABOUT A NOTABLE WIND SHIFT TONIGHT OVER LAKE HURON
TO NORTHWESTERLY...WHILE A TIGHTENED GRADIENT PROVIDES A BOOST TO
WIND SPEEDS WHICH WILL RANGE BETWEEN 20 AND 25 KNOTS POST COLD
FRONT. THIS FLOW WILL CONTINUE THROUGH WEDNESDAY AND WEDNESDAY NIGHT
AS A SECONDARY FRONT THEN DROPS THROUGH THE REGION. HIGH PRESSURE
WILL ALLOW WINDS TO RELAX ON THURSDAY.
&&
.AVIATION...ISSUED 1121 PM EDT MON SEP 7 2015
THE COLD FRONT HAS BASICALLY STALLED ACROSS NORTHERN LOWER AND
CENTRAL WI. THE FORECAST WILL START AS LOWER MI WILL BE IN A WINDOW
OF VERY LITTLE SHOWER ACTIVITY BEFORE THE NEXT WAVE AND JET ENERGY
STARTS TO KICK OFF SHOWERS AGAIN. DEW POINTS STILL AROUND 70 AND
JUST ENOUGH BREAKS AND THIN SPOTS TO HAVE MVFR FOG DEVELOP AGAIN.
COULD BECOME IFR WERE IT RAINED DURING THE EVENING. CEILINGS
OVERNIGHT SHOULD BE AOA 5000 FT.
THE NEXT WAVE STARTS BRING SHOWERS AND STORMS BACK TO MBS AROUND
DAYBREAK...THEN IN THE LATE MORNING TO EARLY AFTERNOON FOR FNT AND
PTK...BUT NOT UNTIL THE MID TO LATE AFTERNOON FOR THE DETROIT TAFS.
WITH THIS NEXT SURGE OF MOISTURE...EXPECT NUMEROUS
SHOWERS...EMBEDDED THUNDERSTORMS...MVFR CIGS AND VISIBILITIES WITH
SOME POTENTIAL FOR IFR VISIBILITIES WITH THE HEAVIEST OF THE RAIN.
FOR DTW...ENOUGH LOW LEVEL MOISTURE TO KEEP THE MVFR FOG FOR THE
EARLY PART OF THE TAF. NEXT THREAT OF RAIN WILL HOLD OFF UNTIL LATER
IN THE DAY ON TUESDAY. IN THE MEANTIME...SOME MOISTURE AROUND THE
5000 FT LEVEL WILL KEEP SCT TO BKN CLOUD COVER FOR MOST OF THE TAF
FORECAST.
FOR DTW...
//DTW THRESHOLD PROBABILITIES...
* LOW CONFIDENCE IN THUNDERSTORMS TUESDAY AFTERNOON.
* LOW CONFIDENCE IN CEILINGS AOB 5000 FEET.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
SHORT TERM...JVC
LONG TERM....DRK
MARINE.......DRK
AVIATION.....99
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
329 AM EDT TUE SEP 8 2015
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/MARINE
.SYNOPSIS...
ISSUED AT 329 AM EDT TUE SEP 8 2015
PERIODS OF SHOWERS AND THUNDERSTORMS WILL PREVAIL TODAY INTO THIS
EVENING BEFORE A SLOW MOVING COLD FRONT PUSHES THEM SOUTH OF THE
AREA BY MID MORNING WEDNESDAY. AREAS OF LOCALIZED HEAVY RAINFALL
ARE POSSIBLE. IT WILL CONTINUE TO BE VERY HUMID TODAY BUT NOT
QUIET AS WARM AS THE PAST FEW DAY. COOLER AND SIGNIFICANTLY DRIER
AIR WILL FOLLOW THE COLD FRONT FOR WEDNESDAY AND SUNSHINE SHOULD
PREVAIL IN MOST AREAS BY MID AFTERNOON. A SECONDARY COLD FRONT
WILL COME THROUGH THE AREA ON FRIDAY WITH SCATTERED SHOWERS. THIS
COMING WEEKEND SHOULD BE MOSTLY CLEAR WITH MUCH COOLER
TEMPERATURES...HIGHS MAY ONLY REACH THE MID 60S ON SATURDAY.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 329 AM EDT TUE SEP 8 2015
OUR PRIMARY ISSUE CONTINUES TO BE THE THREAT FOR HEAVY RAINFALL.
PRECIPITABLE WATER CONTINUES TO RUN BETWEEN 1.8 AND 2.0 INCHES
OVER MOST OF THE CWA TODAY. THIS IS AROUND 3 TIMES NORMAL AND IS
APPROACHING ALL TIME RECORD VALUES FOR THIS TIME OF YEAR. ADD TO
THAT A FRONTAL BOUNDARY SLOWLY MOVING THROUGH THE AREA...AIDED BY
THE ENTRANCE REGION OF THE POLAR JET AND A SHORTWAVE FROM IOWA...
AND THERE IS LITTLE QUESTION SOME OF THE STORMS WILL PRODUCE
HEAVY RAINFALL. CORFIDI VECTORS WILL BE BELOW 10 MILE PER HOUR
THIS MORNING AND RISE TO AROUND 15 MPH THIS AFTERNOON. THAT TOO
WILL AID IN THE LOCALLY HEAVY RAINFALL. I STILL BELIEVE SOME
ISOLATED RAINFALL AMOUNTS MAY BE CLOSE TO 5 INCHES FROM THIS
EVENT.
WE HAVE THE REMAINS OF YESTERDAYS OUTFLOW BOUNDARY STALLED
BETWEEN I-94 AND I-96 EARLY THIS MORNING. AS THE SHORTWAVE FROM
IOWA MOVES CLOSER TO THIS AREA WILL BE THE FOCUS FOR CONVECTION
THIS MORNING. WHICH SUGGESTS THE STORMS WILL MOSTLY BE SOUTH OF
I-96 AT FIRST BUT THEN LIFT NORTHWARD WITH TIME. BY LATE MORNING
INTO EARLY AFTERNOON I WOULD EXPECT MOST OF THE CONVECTION TO BE
NORTH OF I-96. THEN AS THE PRIMARY COLD FRONT AND SHORTWAVE MOVE
INTO THE AREA.. THE RAP MODEL SHOWS A 30 - 35 KNOT LOW LEVEL JET
MOVING INTO THE AREA BY MID AFTERNOON. THE CORE OF THE SPEED MAX
WILL BE JUST NORTH OF I-96 AND BE EAST OF MKG BY 4 PM AND BE NORTH
OF LANSING BY 8 PM. THIS SUGGEST TO ME THE STRONGEST CONVECTION
WILL BE DURING THE LATE AFTERNOON AND EARLY EVENING.
THERE IS A MARGINAL RISK FOR SEVERE STORMS (SPC) TODAY... WITH THE
NARROW CAPE... AND NUMEROUS HEAVY SHOWERS AROUND... AND ONLY
MARGINAL DEEP LAYER SHEAR... I WOULD IMAGINE ANY SEVERE WEATHER
WOULD BE VERY ISOLATED TODAY.
ONCE THE COLD FRONT COMES THROUGH MOST OF THE CONVECTION WILL EXIT
WITH IT THIS EVENING. HIGH PRESSURE FOLLOWS FOR WEDNESDAY INTO
THURSDAY. CLEARING SKIES FROM NORTHWEST TO SOUTHEAST WEDNESDAY
AFTERNOON. I WOULD EXPECT MOSTLY CLEAR SKIES WEDNESDAY NIGHT INTO
THURSDAY AS THE HIGH MOVES OVERHEAD.
BOTTOM LINE IS WET TODAY...DRY WEDNESDAY AFTERNOON INTO THURSDAY
EVENING.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 329 AM EDT TUE SEP 8 2015
A NICE COOL DOWN IS EXPECTED BY THE END OF THE WEEK AS A DEEP UPPER
TROUGH DEVELOPS OVER THE GREAT LAKES. WE/LL SEE TEMPERATURES IN THE
60S FRIDAY THROUGH SUNDAY ALONG WITH SOME SHOWERS FRIDAY AND
SATURDAY. MODEL CONCERNS ARE SIMILAR TO YESTERDAY AS THE ECMWF
DEEPENS THE LOW AND THEN CUTS IT OFF OVER MICHIGAN SUNDAY WHILE THE
GFS KEEPS THE SYSTEM AN OPEN WAVE AND THEN SCOOTS IT EASTWARD BY
SUNDAY. THE GFS WOULD LEAD TO WARMER TEMPS AND LESS PCPN THAN THE
SLOWER COOLER ECMWF. WE/RE LEANING TOWARD THE GFS SOLUTION AS IT
ALSO LINES UP NICELY WITH THE LATEST FIM. THUS ANY SHOWERS SHOULD
END BY LATE SATURDAY LEADING TO DRY WX SUNDAY AND MONDAY AND WARMER
TEMPS AS RIDGING BUILDS INTO SW LWR MI.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 148 AM EDT TUE SEP 8 2015
SHOWERS ARE BEGINNING TO MOVE ACROSS SOUTHERN LOWER MICHIGAN
TOWARD THE SOUTHERN TAF SITES. NOT SEEING LIGHTNING YET IN IT BUT
THAT WILL LIKELY COME BY MID TO LATE MORNING AND THE AFTERNOON AS
A COLD FRONT SAGS ACROSS SW LWR MI. THE POTENTIAL EXIST LATER
TODAY FOR VSBYS TO FALL BELOW WHAT IS IN THE TAF IF A TSRA
DEVELOPS AT THE AIRPORT.
&&
.MARINE...
ISSUED AT 329 AM EDT TUE SEP 8 2015
WINDS AND WAVES SHOULD REMAIN BELOW SMALL CRAFT CRITERIA THROUGH
THURSDAY. EVEN SO THERE MAY BE GUSTY WINDS IN SOME OF THE
THUNDERSTORMS TODAY. VISIBILITIES MAY BE REDUCED TO BELOW A HALF
MILE IN SOME OF THE HEAVY THUNDERSTORMS TODAY.
&&
.HYDROLOGY...
ISSUED AT 1142 AM EDT MON SEP 7 2015
WE MAY RUN THE RISK FOR MINOR FLOODING BETWEEN LATE TONIGHT
THROUGH EARLY WEDNESDAY AS HEAVY RAIN IS POISED TO MARCH ACROSS
THE FORECAST AREA.
A SLOW MOVING FRONTAL BOUNDARY WILL BECOME NEARLY STATIONARY LATE
TONIGHT AND DURING THE DAY TUESDAY. FORECAST PRECIPITABLE WATER
VALUES OF AROUND 2.0 INCHES REMAINS UNCHANGED SINCE PRIOR
FORECASTS. TIMING SEEMS TO BE THE MOST CONSISTENT WITH THIS EVENT.
WHILE RAINFALL WILL BE POSSIBLE FROM TONIGHT THROUGH EARLY WEDNESDAY
AFTERNOON...THE HEAVIEST RAIN IS EXPECTED BETWEEN TUESDAY EVENING
AND WEDNESDAY MORNING.
THE ENTIRE FORECAST AREA CAN COUNT ON ABOUT AND INCH OF
PRECIPITATION...WHILE THE HEAVIEST SWATH LANDS NEAR AND NORTH OF
GRAND RAPIDS. 1-3 SEEMS REALISTIC ALONG AND NORTH OF I-96. THE
CATCH HERE IS THAT THE SOUTHERN HALF OF THE FORECAST AREA...SOUTH
OF I-96 REMAINS ENTRENCHED IN THE WARM SECTOR AND COULD EXPERIENCE
HIGHER INSTANTANEOUS RAINFALL RATES. THIS MEANS THAT HEAVY RAINFALL
THAT DEVELOPS IN SOUTHERN SECTIONS OF THE FORECAST AREA...MAY
RESULT IN LOCALIZED HIGHER TOTALS...4-5 INCHES.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...99
AVIATION...04
HYDROLOGY...JAM
MARINE...WDM
AREA FORECAST DISCUSSION
NWS DULUTH MN
331 AM CDT TUE SEP 8 2015
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 331 AM CDT TUE SEP 8 2015
AT 330 AM...SKIES WERE PARTLY TO MOSTLY CLOUDY ACROSS THE
NORTHLAND. THERE WERE A FEW LIGHT RAIN SHOWERS OR SPRINKLES ACROSS
NW WI...WITH A LARGE AREA OF SHOWERS AND THUNDERSTORMS SOUTH AND
WEST OF THE CWA. TEMPERATURES RANGED FROM NEAR 50 ACROSS THE NORTH
TO THE LOWER 60S IN PORTIONS OF NW WI. WINDS WERE GENERALLY LIGHT.
THE MAIN FOCUS FOR TODAY WILL BE THE POTENTIAL FOR SHOWERS AND
THUNDERSTORMS...ESPECIALLY ACROSS NW WI. THE RAP SEEMS TO HAVE THE
BEST HANDLE ON THE CURRENT TRENDS ACROSS THE UPPER MIDWEST. HAVE
INCREASED POPS ACROSS NW WI THIS MORNING AND WILL HAVE TO KEEP A
CLOSE EYE ON THE CONVECTION STREAMING NORTHEAST FROM SOUTHERN MN.
MAY NEED TO INCREASE POPS EVEN FURTHER DEPENDING ON THE EVOLUTION
OF THE COMPLEX TO OUR SOUTH AS A SHORTWAVE LIFTS TO THE NORTH AND
EAST DURING THE MORNING. THE CHANCE OF PRECIPITATION WILL
GENERALLY INCREASE OVERNIGHT AND EARLY TODAY...AND THEN DECREASE
FROM LATE MORNING THROUGH THIS AFTERNOON. SKIES SHOULD BECOME
PARTLY TO MOSTLY SUNNY ACROSS THE AREA. HIGHS WILL BE IN THE 70S.
WITH CLEAR TO PARTLY CLOUDY SKIES AND HIGH PRESSURE SETTING IN
TONIGHT...WE SHOULD SEE OVERNIGHT LOWS LARGELY IN THE 40S.
WEST TO NORTHWEST FLOW ON WEDNESDAY WILL BRING A COUPLE AREAS OF
POSSIBLE PRECIPITATION AS THE DAY WEARS ON. THE FIRST WILL BE
ACROSS THE NORTH...AS A COLD FRONT DROPS SOUTHWARD ACROSS THE
INTERNATIONAL BORDER. ANOTHER WILL BE FURTHER SOUTH FROM EAST
CENTRAL MN INTO NORTHERN WISCONSIN...AS SHOWERS AND POSSIBLY EVEN
SOME THUNDERSTORMS DEVELOP IN THE AFTERNOON. THE COLD FRONT SHOULD
BE GENERALLY ACROSS THAT AREA BY LATE IN THE DAY. TEMPS WILL BE A
BIT COOLER ON WEDNESDAY...RANGING FROM THE MID 60S NORTH TO THE
LOWER TO MIDDLE 70S SOUTH.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 331 AM CDT TUE SEP 8 2015
THE UPPER PATTERN WILL FEATURE AN UPPER LOW OVER HUDSON BAY EARLY IN
THE PERIOD WITH A TROUGH EXTENDING SOUTH INTO THE NORTHLAND. THE LOW
WILL MOVE EAST THROUGH THE PERIOD WITH NORTHWEST FLOW DEVELOPING.
FINALLY LATE IN THE WEEKEND/EARLY NEXT WEEK THE FLOW WILL BECOME
MORE ZONAL.
SEVERAL SHORTWAVES WILL MOVE THROUGH THE REGION BRINGING A CHANCE
FOR SHOWERS AND PERHAPS A THUNDERSTORM WEDNESDAY NIGHT THROUGH
FRIDAY AND AGAIN MONDAY/TUESDAY. AT THIS TIME...THESE SYSTEMS DO NOT
LOOK PARTICULARLY STRONG WITH THE EXCEPTION OF WEDNESDAY
NIGHT/THURSDAY. THE ECMWF IS SHOWING HIGHER RAINFALL OVER OUR
SOUTHERN ZONES WHICH IS NOT OUT OF THE QUESTION AS THERE SHOULD BE
SOME FGEN FORCING AS THE UPPER WAVE MOVES THROUGH. WE INCREASED POPS
OVER SOUTHERN AREAS A BIT...AND MAY HAVE TO INCREASE QUITE A BIT IF
BETTER AGREEMENT OCCURS AMONG THE MODELS.
TEMPERATURES WILL BE A FEW DEGREES COOLER THAN NORMAL
THURSDAY/FRIDAY/SATURDAY...THEN MODERATE BRIEFLY SUNDAY BEFORE
FALLING BELOW NORMAL AGAIN BY TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1148 PM CDT MON SEP 7 2015
UPPER LEVEL SHORT WAVES WILL PASS OVER THE TERMINALS THROUGH MID
MORNING. THESE SHORT WAVES WILL GENERATE CLOUD COVER AND A FEW
SHOWERS AFTER 15Z ALONG WITH GUSTY WINDS. VFR THROUGH THE
FORECAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 74 49 71 50 / 10 0 20 20
INL 69 43 66 40 / 10 10 20 20
BRD 74 48 73 49 / 10 0 20 30
HYR 77 44 73 49 / 20 0 30 30
ASX 79 48 75 49 / 10 0 20 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...NONE.
&&
$$
SHORT TERM...DAP
LONG TERM...MELDE
AVIATION...GSF
AREA FORECAST DISCUSSION
NWS BILLINGS MT
246 AM MDT TUE SEP 8 2015
.SHORT TERM...VALID FOR TDY AND WED...
DRY AND SEASONABLY WARM WEATHER IS EXPECTED TODAY AND WEDNESDAY
WITH JUST A BIT OF AN AFTERNOON BREEZE IN MOST LOCATIONS.
AS OF 0830 UTC...LIGHT RAIN SHOWERS IN SOUTHEASTERN MT ASSOCIATED
WITH MODEST MID-LEVEL FRONTOGENESIS AND A PASSING SHORTWAVE TROUGH
ARE SHOWING SIGNS OF DECAY. TIME-LAGGED HRRR SIMULATIONS FROM BOTH
THE OPERATIONAL AND EXPERIMENTAL VERSION OF THE MODEL SUGGEST THAT
THESE SHOWERS WILL BE COMPLETELY GONE BY ABOUT 12 UTC AND THE REST
OF THE 00 UTC GUIDANCE AGREES...SO WE HAVE STARTED THE DAY WITH A
DRY FORECAST EVERYWHERE AFTER SUNRISE.
FOR TODAY...DRY NORTHWEST FLOW WILL PREVAIL ALOFT AND LOOKS DEVOID
OF ADDITIONAL SHORTWAVE TROUGHS OF ANY SIGNIFICANCE...SO WE EXPECT
A QUIET DAY. FORECAST SOUNDINGS SUPPORT MIXING TO ABOUT 650-MB IN
MOST AREAS AND WITH A BIT OF WARMING ALOFT HIGHS WILL TAKE A STEP
UPWARD FROM YESTERDAY...WITH FORECAST VALUES WELL INTO THE 70S F.
HUMIDITIES WILL FALL TO BETWEEN 15 AND 20 PERCENT IN SOUTH CENTRAL
MT AND PERHAPS NORTH CENTRAL WY THIS AFTERNOON...AND THERMAL GUSTS
TO 30 MPH ARE LIKELY IN THE LIVINGSTON AND BIG TIMBER AREAS DURING
PEAK HEATING WHEN THE BOUNDARY LAYER IS DEEPEST. THAT WILL PRODUCE
ELEVATED FIRE DANGER IN THAT AREA FOR A FEW HOURS THIS AFTERNOON.
TONIGHT...LOWS WILL BE IN THE 40S TO AROUND 50 F AS DRY NORTHWEST
FLOW CONTINUES ALOFT.
WEDNESDAY...THE 00 UTC GUIDANCE SHOWS A WEAK SURFACE LOW DROPPING
INTO ND DURING THE DAY...PLACING SOUTHERN MT AND NORTHERN WY IN
THE WARM SECTOR OF THAT FEATURE AHEAD OF A SOUTHWARD-MOVING COOL
FRONT. THIS SCENARIO WILL LIKELY ENHANCE THE EFFICIENCY OF LOW-
LEVEL TURBULENT MIXING...SO WE HAVE LEANED TOWARD THE WARMER SIDE
OF THE 00 UTC MODEL GUIDANCE FOR FORECAST HIGHS AROUND 80 F OVER
MOST OF THE AREA. WE LEFT A DRY FORECAST IN PLACE WEDNESDAY NIGHT
EVEN AS THE COOL FRONT SETTLES ACROSS THE AREA GIVEN THE LACK OF
APPRECIABLE FORCING ALOFT IN MOST 00 UTC MODEL SOLUTIONS. SCHULTZ
.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...
AN UPPER RIDGE GRADUALLY BUILDS INTO THE NORTHERN ROCKIES THROUGH
THE END OF THE WEEK UNDER WEAKENING NORTHWEST FLOW ALOFT. THIS
WILL KEEP THE FORECAST DRY AND PROMOTE WARMER TEMPERATURES INTO
THE EARLY PART OF THE WEEKEND. IN FACT...TEMPERATURES LOOK TO
APPROACH 90 DEGREES ON SATURDAY. MODELS LOWER HEIGHTS SOME SUNDAY
INTO MONDAY AS A COLD FRONT MOVES THROUGH. THIS FRONT IS PROGGED
WEAKER THAN THE LAST SEVERAL MODEL RUNS. GUIDANCE NOW ONLY LOWERS
HIGHS TO THE MID 70S ON MONDAY...WHICH ARE CLIMATE AVERAGES. HAVE
INCLUDED CHANCE POPS STARTING SUNDAY NIGHT WITH THE COLD FRONT AND
LINGERING THEM INTO EARLY NEXT WEEK WITH LOWERING HEIGHTS AND WEAK
ENERGY STREAMING IN FROM THE WEST.
IT SHOULD BE NOTED THAT BEYOND MONDAY...MODELS DIVERGE FOR THE
WEATHER PATTERN INTO THE MIDDLE OF NEXT WEEK. THE GFS WAS MORE
AGGRESSIVE ON A TROUGH SLIDING INTO MONTANA FROM THE NORTHWEST
PROVIDING A DECENT COOL DOWN. THE ECMWF WEAKENS THE TROUGH
TREMENDOUSLY OVER BRITISH COLUMBIA AND ACTUALLY DEVELOPS SOUTHWEST
FLOW OVER THE GREAT BASIN...FOR A MUCH WARMER REGIME. THE ECMWF
HAS NOT BEEN CONSISTENT OF LATE BEYOND 180 HOURS AND GREATLY
HESITATE FOLLOWING IT. THAT BEING SAID...THE GFS HAS BACKED OFF
QUITE A BIT ON THE DEPTH OF THE TROUGH FOR TUESDAY AS WELL.
INDICATIONS SEEM TO BE POINTING AWAY FROM A STRONG COOL DOWN NEXT
WEEK. WILL CONTINUE TO MONITOR. TWH
&&
.AVIATION...
CLOUDS WILL DECREASE FROM KBIL EASTWARD THIS MORNING AS A
DISTURBANCE EXISTS THE AREA. VFR FLYING WEATHER IS ANTICIPATED
TODAY. WEST TO NORTHWEST WINDS WILL INCREASE THIS AFTERNOON AS THE
DAY HEATS UP. SOME GUSTS TO 25 KTS CAN BE EXPECTED AT KLVM WITH
GUSTS NEAR 20KTS AT KMLS AND KBIL. TWH
&&
.PRELIMINARY POINT TEMP/POPS...
TDY WED THU FRI SAT SUN MON
-------------------------------------------------------
BIL 076 051/080 050/078 050/081 052/087 056/084 050/075
0/B 00/B 10/U 11/U 00/U 01/U 22/W
LVM 076 045/081 046/080 045/082 048/086 049/083 048/077
1/N 00/B 10/U 00/U 00/U 11/U 23/W
HDN 078 048/082 049/079 048/082 050/088 053/085 049/079
1/B 00/B 11/B 11/U 00/U 01/U 22/W
MLS 075 051/079 050/076 049/079 052/086 055/084 049/075
1/B 00/B 11/B 11/U 00/U 00/U 22/W
4BQ 074 050/079 051/076 049/079 051/085 054/086 052/077
1/B 00/B 11/B 00/B 00/U 00/U 22/W
BHK 073 048/077 047/072 045/076 048/082 051/082 049/072
1/B 00/B 11/B 11/B 00/U 00/U 22/W
SHR 077 044/081 046/079 045/083 046/085 049/085 048/080
1/U 00/B 11/B 11/U 00/U 01/U 22/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1131 PM MDT MON SEP 7 2015
.AVIATION...
06Z TAF CYCLE
SCT SHOWERS WILL CONTINUE TO WEAKEN AND DIMINISH THROUGH THE
OVERNIGHT HOURS. VFR CONDITIONS SHOULD PREVAIL. TUESDAYS CROP
OF SHOWERS AND STORMS WILL BE LESS IN COVERAGE THAN TODAY...WITH
ISOL TO SCT CONVECTION FAVORING THE SOUTH AND EAST. CHJ
&&
.PREV DISCUSSION...302 PM MDT MON SEP 7 2015...
.SYNOPSIS...
STORMS WILL CONTINUE THIS EVENING LARGELY FOR AREAS SOUTH OF
INTERSTATE 40 WHERE SPOTTY LOCATIONS MAY SEE A HALF INCH OR MORE
OF RAIN. A BACK DOOR COLD FRONT WILL SLIDE DOWN THE PLAINS
TUESDAY AND TUESDAY NIGHT BEFORE PUSHING THROUGH THE GAPS OF THE
CENTRAL MOUNTAIN CHAIN WEDNESDAY MORNING. SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE BEHIND THE FRONT ACROSS THE PLAINS.
TEMPERATURES WILL COOL IN THE WAKE OF THE FRONT...BUT WILL STILL
BE RIGHT AROUND NORMAL VALUES FOR EARLY SEPTEMBER WEDNESDAY
AFTERNOON. MID LEVEL DRY AIR WILL CONTINUE TO PUSH INTO THE STATE
ON THURSDAY AND FRIDAY...BUT ANOTHER BACK DOOR FRONT WILL BE
LURKING AS WELL.
&&
.DISCUSSION...
MOST OF THE RATHER WELL-BEHAVED STORMS TODAY HAVE STAYED SOUTH OF
I-40 AS EXPECTED. HRRR SUGGESTS THAT THE ABQ METRO AREA MAY SEE
SOME ACTION SHORTLY AFTER 00Z...BUT MOST OF THE ACTIVITY SHOULD
END BY MIDNIGHT ACROSS ALL AREAS.
STILL LOOKING FOR A BACK DOOR COLD FRONT TO MOVE INTO AT LEAST NE
NM ON TUESDAY BEFORE SLIDING SOUTH AND WEST TUESDAY NIGHT. THE
FRONT CONTINUES TO LOOK STRONGER WITH EACH MODEL RUN...AND A
BREEZY EAST CANYON WIND NOW LOOKS MORE LIKELY EARLY WEDNESDAY
MORNING FOR THE RIO GRANDE VALLEY. THE BIGGEST QUESTION CONTINUES
TO BE HOW MUCH PRECIPITATION WILL ACCOMPANY THE FRONT. GFS
CONTINUES TO BE VERY BULLISH BREAKING OUT STORMS ACROSS MUCH OF
EASTERN NM IN MOIST UPSLOPE FLOW TUESDAY NIGHT. OTHER MODELS ARE
LESS ENTHUSED. IT CERTAINLY SEEMS POSSIBLE SINCE MODELS ARE NOT
SHOWING AS MUCH DRYING AT MID LEVELS AS THEY WERE
YESTERDAY...EXCEPT FOR IN THE FAR NW. GIVING A NOD TO THE GFS
ENSEMBLE MEMBERS...WHICH ARE MUCH LIKE THEIR OPERATIONAL
COUNTERPART... BUMPED UP POPS A BIT MORE ACROSS THE EAST.
MOST MODELS NOW SHOWING CONVECTION ALONG THE CENTRAL MTN CHAIN ON
WEDNESDAY AFTERNOON WITH CONTINUED MOIST UPSLOPE FLOW. STORMS
SHOULD BE MORE ROBUST SOUTH OF I-40 WHERE MID LEVEL DRYING IS NOT
AS PREVALENT. HIGH TEMPERATURES ON WEDNESDAY SHOULD DROP AT LEAST
3 TO 8 DEGREES FROM TUESDAYS READINGS...THOUGH THIS WILL MEAN
TEMPS WILL ACTUALLY BE RIGHT AROUND NORMAL.
THE MID LEVEL DRY AIR NUDGES IN FARTHER ON THURSDAY...AND
CONVECTIVE COVERAGE SHOULD WANE A BIT. AREAS SOUTH OF HWY 60
SHOULD HAVE THE BEST STORM CHANCES. THEREAFTER...CONFIDENCE
REMAINS VERY LOW AS MODELS CONTINUE TO YO-YO THE NEXT BACK DOOR
FRONT AROUND. THE ECMWF IS BACK ON SCHEDULE FOR THE FRONT TO
ARRIVE ON FRIDAY...WHILE THE GFS IS AROUND 12 HOURS LATER AND ALSO
MUCH STRONGER. THIS WILL OBVIOUSLY HAVE SERIOUS IMPLICATION ON
POPS AND TEMPS...SO GENERALLY WENT FOR A MIDDLE OF THE ROAD
FORECAST FOR NOW.
34
&&
.FIRE WEATHER...
HIGH PRESSURE ALOFT IS FORECAST TO BUILD INTO THE GREAT BASIN THIS
WEEK...EVENTUALLY CUTTING OFF THE FLOW OF MOISTURE FROM THE
SOUTH...WHILE SHUNTING HURRICANE LINDA WEST OF BAJA CA/SOCAL. THIS
SHOULD LEAD TO A DRYING TREND FOR WESTERN NEW MEXICO. LOW LEVEL
MOISTURE WILL SLOSH BACK AND FORTH OVER CENTRAL AND EASTERN NEW
MEXICO THIS WEEK...DEPENDING ON TIMING OF 2 BOUNDARIES...ONE
EXPECTED TUESDAY/TUESDAY NIGHT AND A SECOND...WHICH THE GFS IS NOW
PORTRAYING AS STRONGER THAN IT HAS IN SEVERAL RUNS...ON
FRIDAY/FRIDAY NIGHT.
SO FAR THIS AFTERNOON...MOST OF THE CONVECTION HAS BEEN RELEGATED TO
AREAS ALONG AND SOUTH OF INTERSTATE 40...AS THE HRRR SUGGESTED.
WETTING RAIN FOOTPRINTS TO BE FAIRLY SMALL AS CELLS TRACK TO THE
EAST/NORTHEAST...AND ACTIVITY IS INDICATED TO DIMINISH BY MID
EVENING.
TUESDAY/WEDNESDAY ARE TRANSITION DAYS IN WHICH THE UPPER AIR PATTERN
SHIFTS FROM WEST TO NORTHWEST/NORTH WINDS ALOFT...IMPORTING
CONSIDERABLY DRIER AIR AT THE MID LEVELS. THE SURFACE BOUNDARY FOR
TUESDAY/TUESDAY NIGHT APPEARS A BIT MORE VIGOROUS AND MAY PUSH SOME
LOW LEVEL MOISTURE INTO THE RGV...WHICH MIXES OUT TO SOME EXTENT
WEDNESDAY...WHEN BEST CHANCES FOR WETTING RAIN WILL BECOME FOCUSED
ALONG THE CENTRAL MT CHAIN AND SOUTH OF I-40. PRECIPITATION CHANCES
TAPER DOWN THURSDAY INTO FRIDAY...BUT ANOTHER BOUNDARY COULD
REPLENISH LOW LEVEL MOISTURE INTO THE CENTRAL/EAST BY SATURDAY.
TOWARDS THE END OF THIS WEEK...AND INTO NEXT WEEK...FORECAST
VARIABLES CONTINUE TO BE QUITE VARIABLE WITH RUN TO RUN MODEL FLIP
FLOPPING. THE 12Z GFS DEVELOPS A VIGOROUS SHORT WAVE/CLOSED LOW ON
THE EASTERN PERIPHERY OF THE UPPER RIDGE OVER ERN NM/CHIHUAHUA THIS
WEEKEND THEN EJECTS IT NEWD EARLY NEXT WEEK. THE ECMWF HAS OTHER
IDEAS...MAINLY A 590 PLUS HIGH CENTER OVER NM. IN FACT...THE DEEP
UPPER TROF DEPICTED 24 HRS AGO BY BOTH NEAR 240 HRS HAS VANISHED.
KEEPING THE LOW CONFIDENCE IN MIND...HIGH HAINES WILL BE FOUND OVER
PORTIONS OF CENTRAL AND WRN NM MID TO LATE THIS WEEK. POOR OVERNIGHT
RECOVERIES WILL PLAGUE PORTIONS OF THE NW DURING THIS TIME...AND MIN
RH VALUES MAY FALL BELOW 15 PERCENT. HIGHS WILL BE CLOSE TO AVERAGE
FOR THE SEASON THROUGH THE UPCOMING WEEKEND. OVERNIGHT LOWS MAY FALL
TO NEAR FREEZING AT SOME OF THE NRN MT HIGHER TERRAIN OBS SITES MID
TO LATE WEEK. VENT RATES FORECAST TO BE GOOD TO EXCELLENT
TUESDAY...THEN DECREASE WEDNESDAY WITH AREAS OF FAIR TO POOR
FORECAST ALONG AND SOUTH OF I-40. WIDESPREAD FAIR TO POOR RATES
ANTICIPATED FRIDAY CENTRAL AND EAST.
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BUFFALO NY
542 AM EDT TUE SEP 8 2015
.SYNOPSIS...
HIGH PRESSURE OVER THE MID ATLANTIC COAST WILL CONTINUE TO BRING
MIDSUMMERLIKE CONDITIONS TO THE REGION THROUGH THE FIRST HALF OF
WEDNESDAY...BEFORE A COLD FRONT CROSSES OUR REGION BETWEEN LATER
WEDNESDAY AND WEDNESDAY NIGHT. THIS FRONT WILL BE ACCOMPANIED BY
NUMEROUS SHOWERS AND THUNDERSTORMS AS IT PASSES THROUGH...AND WILL
BE FOLLOWED BY PROGRESSIVELY COOLER WEATHER DURING THE REMAINDER
OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 08Z...REGIONAL SURFACE OBSERVATIONS SUGGEST THAT THE WEAK
COLD FRONTAL BOUNDARY EXTENDS FROM THE SAINT LAWRENCE VALLEY
ACROSS NORTHERN LAKE ONTARIO TO THE GREATER TORONTO AREA...AND
THEN ON ACROSS SOUTHWESTERN ONTARIO. ALONG AND NEAR THIS
BOUNDARY...REGIONAL RADARS CONTINUE TO DEPICT AN ELONGATED SWATH
OF ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS.
DURING THE COURSE OF TODAY...THE WEAK COLD FRONT WILL BRIEFLY
STALL OUT ALONG OR SLIGHTLY NORTH OF OUR NORTHERN PERIPHERY THIS
MORNING... BEFORE LIFTING BACK NORTH THIS AFTERNOON AS A WARM
FRONT IN RESPONSE TO THE DEVELOPMENT OF BROAD LOW PRESSURE OVER
THE UPPER GREAT LAKES. ALONG AND NEAR THIS BOUNDARY...THERE WILL
BE A CONTINUED RISK OF SCATTERED SHOWERS AND THUNDERSTORMS THROUGH
THE DAY...WITH THIS RISK LYING ROUGHLY FROM THE NYS THRUWAY
CORRIDOR NORTHWARD THROUGH LATE THIS MORNING...THEN DIMINISHING
FROM SOUTHWEST TO NORTHEAST LATE THIS MORNING AND THIS AFTERNOON
AS THE FRONT BEGINS LIFTING BACK NORTH.
IN ADDITION TO ANY FRONTAL CONVECTION...THE COMBINATION OF
DIURNAL HEATING OF OUR VERY WARM AND HUMID AIRMASS AND
REDEVELOPING LAKE BREEZE BOUNDARIES MAY ALSO LEAD TO THE
DEVELOPMENT OF A SECOND REGION OF ISOLATED TO SCATTERED CONVECTION
ACROSS AREAS SOUTH OF LAKE ONTARIO THIS AFTERNOON...WITH THIS
PRIMARILY FOCUSED FROM INTERIOR PORTIONS OF THE SOUTHERN TIER AND
GENESEE VALLEY EASTWARD ACROSS THE FINGER LAKES.
WITH ALL OF THE ABOVE IN MIND...HAVE CONTINUED TO DEPICT A
GENERAL SOUTHWEST-NORTHEAST GRADIENT IN PRECIPITATION
PROBABILITIES FOR TODAY...WITH THESE RANGING FROM HIGH CHANCE
ACROSS THE SAINT LAWRENCE VALLEY AND NORTH COUNTRY...TO BELOW
SLIGHT CHANCE IN AN EXPECTED REGION OF LAKE SHADOWING IMMEDIATELY
EAST OF LAKE ERIE.
OUTSIDE OF THE AFOREMENTIONED CONVECTION...DRY WEATHER AND
MIDSUMMERLIKE WARMTH AND HUMIDITY SHOULD AGAIN PREVAIL ACROSS OUR
REGION TODAY. SURFACE DEWPOINTS WILL RANGE FROM THE LOWER 60S
ACROSS INTERIOR PORTIONS OF THE SOUTHERN TIER TO NEAR 70 ALONG THE
STALLED/RETREATING FRONTAL BOUNDARY...WHILE 850 MB TEMPS OF +16C
TO +19C WILL SUPPORT HIGH TEMPERATURES RANGING FROM THE LOWER 80S
ACROSS THE NORTH COUNTRY TO THE MID AND UPPER 80S ACROSS MOST OF
THE REST OF THE REGION...ALONG WITH SOME 90 DEGREE READINGS ACROSS
THE NORMAL WARM SPOTS OF THE GENESEE VALLEY/FINGER LAKES.
TONIGHT...THE WARM FRONT WILL FINISH LIFTING OFF TO OUR NORTH
EARLY IN THE EVENING. WITH THE DEPARTURE OF THIS FEATURE AND THE
LOSS OF DAYTIME HEATING...ANY LINGERING CONVECTION ACROSS THE
FINGER LAKES AND NORTH COUNTRY WILL COME TO AN END THIS
EVENING...LEAVING BEHIND LARGELY DRY WEATHER FOR THE BALANCE OF
THE NIGHTTIME HOURS AS OUR REGION WILL BE FIRMLY ENTRENCHED WITHIN
THE WARM SECTOR OF LOW PRESSURE LIFTING BY WELL TO OUR NORTHWEST.
THUS...WE CAN EXPECT YET ANOTHER UNSEASONABLY WARM NIGHT ACROSS
OUR REGION...WITH OVERNIGHT LOWS AGAIN RANGING FROM THE MID 60S
ACROSS INTERIOR PORTIONS OF THE SOUTHERN TIER TO THE LOWER 70S
ACROSS THE LAKE PLAINS...OR LEVELS THAT WILL BE NOT THAT FAR OFF
FROM NORMAL HIGH TEMPERATURES FOR EARLY SEPTEMBER.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
TEMPERATURES WILL RETURN TO NEAR NORMAL LEVELS ACROSS THE LOWER
GREAT LAKES DURING THIS PERIOD...AS THE UPPER LEVEL FLOW ACROSS
NORTH AMERICA WILL FEATURE AN AMPLIFYING TROUGH OVER THE EASTERN
HALF OF THE CONTINENT. THIS WILL BE SIGNIFICANT CHANGE FROM THE
FIRST WEEK OF SEPTEMBER WHEN A PERSISTENT SUB-TROPICAL RIDGE
DOMINATED THE EASTERN HALF OF THE COUNTRY. WHILE THE RIDGE WAS NOT
OVERLY IMPRESSIVE `ON PAPER`...ITS STAYING POWER FOR THIS TIME OF
YEAR ALLOWED FOR ANOMALOUSLY WARM AIR AND PLENTY OF GULF HUMIDITY
TO CREATE THE WARMEST STRETCH OF WEATHER OUR REGION EXPERIENCED
ALL SUMMER. WITH THE PASSING OF THE LAST SUMMER HOLIDAY...MOTHER
NATURE WILL ALSO TURN THE PAGE...ALBEIT IT SLOWLY.
AS IS SO OFTEN IS THE CASE...A STRONG LATITUDINAL H25 JET
CROSSING THE NORTHERN PACIFIC WILL PLOW ACROSS THE CANADIAN
ROCKIES AND ESTABLISH A BROAD DOWNSTREAM TROUGH OVER THE EASTERN
HALF OF THE CONTINENT. THIS TROUGH WILL FLATTEN THE PERTINACIOUS
SUB TROPICAL RIDGE...AND IN TIME WILL DIRECT PROGRESSIVELY COOLER
CANADIAN AIR SOUTHWARDS ACROSS THE LOWER 48. THIS COOLING WILL
INITIALLY ONLY TAKE OUR TEMPERATURES BACK TOWARDS NORMAL...BUT AS
WE HEAD IN TO THE WEEKEND...WE COULD EXPERIENCE A DAY OR TWO OF
FALL LIKE CONDITIONS.
AN INVERTED SFC TROUGH EXTENDING FROM THE UPPER GREAT LAKES TO
THE CENTRAL PLAINS LATE TUESDAY NIGHT WILL GRADUALLY EVOLVE INTO A
LEGITIMATE...ALBEIT WAVY...COLD FRONT ON WEDNESDAY AS IT WILL PUSH
SOUTHEAST ACROSS THE LOWER GREAT LAKES. THE OVERALL SYNOPTIC
FORCING WITH THE SLOW MOVING FRONTAL BOUNDARY IS NOT BEING
ADVERTISED AS BEING ALL THAT IMPRESSIVE...BUT IT WILL BE ENOUGH IN
COMBINATION WITH THE MID SUMMER LIKE THERMODYNAMIC ENVIRONMENT TO
PRODUCE INCREASINGLY NUMEROUS SHOWERS AND POTENTIALLY STRONG
THUNDERSTORMS.
ADDRESSING THE FORMER FIRST...AS EARLIER MENTIONED THE FRONTAL
BOUNDARY WILL STILL BE TAKING SHAPE DURING THE DAY WEDNESDAY AS IT
WILL BE PUSHING INTO OUR FORECAST AREA. TRUE FRONTOGENETIC FORCING
FROM THE FRONT WILL THUS BE GENERALLY WEAK...ALTHOUGH HGT FALLS
AND A 120KT H25 JET OVER NORTHERN QUEBEC WILL ADD SOME LARGE SCALE
SYNOPTIC LIFT BY PLACING OUR FORECAST AREA UNDER RR QUAD OF THE
JET ENTRANCE REGION. THERMODYNAMICALLY...OUR WARM HUMID AIRMASS
WILL ALREADY BE UNSTABLE. SBCAPES WILL ALREADY BE IN THE HUNDREDS
AS WE OPEN THE DAY...AND DIMINISHING MORNING SUNSHINE WILL ONLY
ADD TO THIS INSTABILITY...PARTICULARLY OVER PARTS OF THE SRN TIER
AND FINGER LAKES REGIONS WHERE MUCAPES COULD APPROACH 2000 J/KG.
MEANWHILE A SWATH OF TROPICAL MOISTURE TO THE TUNE OF 2 INCH PWAT
VALUES WILL STREAM ACROSS OUR REGION ALONG AND AHEAD OF THE SFC
BOUNDARY...SO THIS IN COMBINATION WITH THE SYNOPTIC FORCING AND
INSTABILITY COULD RESULT IN TORRENTIAL DOWNPOURS WITH SOME OF THE
CONVECTION. FORTUNATELY...THE REGION IS PARCHED FROM A GENERAL
LACK OF RAINFALL FROM THE PAST MONTH OR SO...AND GUIDANCE IS
SUGGESTING THAT CORFIDI VECTORS WILL LENGTHEN AS THE FRONT
APPROACHES. THIS WILL LESSEN THE RISK FOR WIDESPREAD HYDRO RELATED
PROBLEMS...BUT LOCAL ISSUES WILL STILL HAVE TO BE ADDRESSED GIVEN
THE SUB TROPICAL ENVIRONMENT. THE MENTION OF TORRENTIAL DOWNPOURS
HAS ALREADY BEEN ADDED TO THE HWO PRODUCT AND TO THE GRIDDED DATA
BASE...SO WILL CONTINUE.
ALONG WITH THE THREAT FOR LOCALLY HEAVY CONVECTIVE RAINS...THERE
WILL BE AN ISOLATED RISK FOR STRONG THUNDERSTORMS. THIS POTENTIAL
WILL BE ATTENUATED BY UNIMPRESSIVE MID LEVEL LAPSE RATES UNDER 6
DEG C/KM...BUT GIVEN BULK SHEAR VALUES OF 35 TO 40 KNOTS AND THE
UNCERTAINTY AS TO HOW MUCH SUNSHINE PARTS OF THE REGION RECEIVE...
WE WILL CONTINUE TO HIGHLIGHT THE CHANCE FOR GUSTY CONVECTIVE
WINDS.
CONSIDERING ALL OF THE ABOVE...WEDNESDAY SHOULD START OFF DRY
ACROSS OUR FORECAST AREA...BUT AS THE FRONT NEARS DURING THE
MIDDAY...CONVECTION WILL BEGIN TO BREAK OUT. THIS MAY BE HASTENED
ACROSS PARTS OF THE SRN TIER AND FINGER LAKES REGION WHERE A LAKE
BREEZE BOUNDARY COULD FOCUS AN INITIAL ROUND OF STORMS...THEN AS
THE FRONT SLOWLY CROSSES THE LOWER GREAT LAKES IN THE AFTERNOON
AND EVENING...THE GENERAL CONDITIONS WILL FURTHER DETERIORATE.
WILL MAINTAIN LIKELY POPS REGIONWIDE FOR THE LATE AFTERNOON...
BUT THE VAST MAJORITY OF THE DAY SHOULD BE RAIN FREE. OTHERWISE
WEDNESDAY WILL BE WARM AND HUMID WITH MAX TEMPS RANGING FROM THE
LOWER 80S OVER THE FAR WEST TO THE MID AND POSSIBLY UPPER 80S
ACROSS PARTS OF THE FINGER LAKES.
DURING THE COURSE OF WEDNESDAY NIGHT...THE FRONTAL BOUNDARY WILL
LAZILY CROSS OUR FORECAST AREA AS UPSTREAM SFC WAVES WILL RETARD
ITS FORWARD PROGRESS. THIS IS THE TIME PERIOD WHERE THE AXIS OF
THE DEEPEST MOISTURE WILL CROSS OUR FORECAST AREA. WHILE DIURNALLY
ENHANCED INSTABILITY WILL BE WANING...THE PASSAGE OF ANY WAVES
ALONG THE FRONTAL BOUNDARY COULD SYNOPTICALLY ENHANCE ANY SHOWERS
INTO A 2 TO THREE HOUR PERIOD OF STEADIER RAIN. THIS POTENTIAL
WILL BE GREATEST OVER THE SRN TIER AND FINGER LAKES REGION.
AGAIN...WE WILL BE FORTUNATE IN THAT WE HAVE VERY DRY ANTECEDENT
CONDITIONS.
ON THURSDAY...WEAK HIGH PRESSURE OVER LOWER MICHIGAN WILL
GRADUALLY BUILD ACROSS OUR FORECAST AREA WHILE THE FLEXUOUS
FRONTAL BOUNDARY WILL MAKE ITS WAY TO THE EAST COAST. SHOWERS...
THAT WILL BE MOST LIKELY EAST OF LINE FROM ROCHESTER TO
JAMESTOWN...WILL TAPER OFF FROM WEST TO EAST IN THE PROCESS.
SUNSHINE SHOULD RETURN IN FORCE TO THE NIAGARA FRONTIER AND PARTS
OF THE SRN TIER BY THE AFTERNOON...BUT THE IMPROVEMENT WILL TAKE
LONGER FURTHER EAST. IT WILL START TO FEEL MUCH MORE COMFORTABLE
AS WELL...AS THE FRESH AIRMASS WILL START TO SETTLE OVER THE
REGION WITH DEW POINTS OVER THE WESTERN COUNTIES STEADIER FALLING
THROUGH THE 50S. AFTER NEARLY TWO WEEKS OF AFTERNOON TEMPERATURES
IN THE 80S...MAX TEMPS ON THURSDAY SHOULD FINALLY RETURN TO THE
70S.
THE GRADUAL CLEARING PROCESS WILL CONTINUE THURSDAY NIGHT AS THE
LEADING EDGE OF HIGH PRESSURE WILL WORK ACROSS OUR FORECAST AREA.
ANY LEFTOVER SHOWERS OVER EASTERN SECTIONS SHOULD END DURING THE
EVENING WITH MUCH MORE COMFORTABLE SLEEPING CONDITIONS GAINING A
FOOTHOLD OVER THE ENTIRE FORECAST AREA. OVERNIGHT LOWS WILL
GENERALLY BE IN THE 50S...WITH THE RADIATIONAL COOLING PROBABLY
LEADING TO SOME VALLEY FOG ACROSS PARTS OF THE SRN TIER AND FINGER
LAKES REGIONS.
WHILE PLEASANT WEATHER IS EXPECTED ACROSS OUR REGION ON FRIDAY...
A MID LEVEL DISTURBANCE DIGGING INTO THE GREAT LAKES LONGWAVE
TROUGH WILL ENCOURAGE SOME `BAGGINESS` IN THE SFC PRESSURE FIELD
ACROSS THE UPPER OHIO VALLEY. THIS WILL BE THE BEGINNINGS OF WHAT
COULD POTENTIALLY BE A CLOSED LOW FOR OUR REGION DURING THE
UPCOMING WEEKEND. MORE ON THIS LOW CONFIDENCE EVENT IN THE LONG
TERM SECTION BELOW. GENERALLY PARTLY SUNNY SKIES CAN BE EXPECTED
ON FRIDAY WITH AFTERNOON TEMPERATURES IN THE 70S BEING ACCOMPANIED
BY COMFORTABLY LOW HUMIDITY LEVELS.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
ONCE AGAIN...THE MEDIUM RANGE GUIDANCE PACKAGES ARE VASTLY
DIFFERENT IN THEIR SOLUTIONS OVER THE LOWER GREAT LAKES IN THE
DAYS 5-7 PERIOD. BOTH THE GFS AND ECMWF OPERATIONAL MODELS ARE
STUBBORNLY HOLDING ONTO THE SAME SCENARIOS THAT THEY HAVE BEEN
PREACHING FOR THE PAST COUPLE DAYS... WITH THE LATTER DEPICTING
THE DEVELOPMENT OF A STACKED STORM SYSTEM OVER SOUTHERN ONTARIO
AND THE LOWER GREAT LAKES. NEEDLESS TO SAY...THIS WOULD BE A VERY
UNSETTLED SOLUTION FOR OUR FORECAST AREA WITH FAIRLY WIDESPREAD
FREQUENT SHOWERS.
BECAUSE OF THE DISPARITY WITHIN THE GUIDANCE PACKAGES...HAVE NO
CHOICE BUT TO KEEP THE LOW/SLGT CHC BROADBRUSH POPS THAT ARE IN
CONTINUITY IN PLACE THROUGH AT LEAST THE WEEKEND.
&&
.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
A WEAK COLD FRONT WILL BRIEFLY STALL OUT ALONG OR SLIGHTLY NORTH
OF OUR NORTHERN PERIPHERY THIS MORNING...BEFORE LIFTING BACK NORTH
THIS AFTERNOON AS A WARM FRONT IN RESPONSE TO THE DEVELOPMENT OF
BROAD LOW PRESSURE OVER THE UPPER GREAT LAKES. THERE WILL BE A
CONTINUED RISK OF SCATTERED SHOWERS/THUNDERSTORMS AND ATTENDANT
BRIEF LOCALIZED RESTRICTIONS ALONG AND NEAR THIS BOUNDARY THROUGH
THE DAY...AND ALSO ALONG AND INLAND FROM A DEVELOPING LAKE ERIE
LAKE BREEZE BOUNDARY DURING THE AFTERNOON. OUTSIDE OF ANY SUCH
CONVECTION AND ANY EARLY MORNING SOUTHERN TIER VALLEY FOG...VFR
CONDITIONS SHOULD OTHERWISE PREVAIL.
TONIGHT...THE FRONTAL BOUNDARY WILL FINISH LIFTING OFF TO OUR
NORTH EARLY IN THE EVENING. WITH THE DEPARTURE OF THIS FEATURE AND
THE LOSS OF DAYTIME HEATING...ANY LINGERING CONVECTION/ATTENDANT
RESTRICTIONS ACROSS THE FINGER LAKES AND NORTH COUNTRY WILL COME
TO AN END THIS EVENING...LEAVING BEHIND LARGELY DRY/VFR CONDITIONS
FOR THE BALANCE OF THE NIGHTTIME HOURS.
OUTLOOK...
WEDNESDAY...MAINLY VFR INITIALLY...THEN SHOWERS AND THUNDERSTORMS
WITH ATTENDANT REDUCTIONS TO IFR/MVFR BECOMING LIKELY FOR WEDNESDAY
AFTERNOON AND EVENING.
THURSDAY...SCATTERED TO NUMEROUS SHOWERS TAPERING OFF WITH CONDITIONS
IMPROVING TO VFR.
FRIDAY...MAINLY VFR...EXCEPT IN POSSIBLE MORNING SOUTHERN TIER
VALLEY FOG.
SATURDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
HIGH PRESSURE CENTERED OVER THE MID ATLANTIC COASTLINE WILL SLOWLY
DRIFT OFFSHORE THROUGH MIDWEEK. A STALLED OUT COLD FRONT DRAPED FROM
THE SAINT LAWRENCE VALLEY SOUTHWESTWARD ACROSS LAKE ONTARIO WILL LIFT
BACK NORTH OF THE REGION AS A WARM FRONT THIS AFTERNOON AND EVENING
IN RESPONSE TO DEVELOPING LOW PRESSURE ACROSS THE UPPER GREAT LAKES...
THEN THIS LATTER FEATURE WILL SLOWLY EASE ITS TRAILING COLD FRONT
ACROSS THE AREA WEDNESDAY AFTERNOON AND NIGHT.
THE INITIAL FRONTAL BOUNDARY WILL CONTINUE TO TRIGGER SCATTERED
SHOWERS AND THUNDERSTORMS AS IT LINGERS NEAR THE LOWER GREAT LAKES
THIS MORNING...WITH THESE THEN GRADUALLY DIMINISHING FROM SOUTHWEST
TO NORTHEAST THIS AFTERNOON AND EVENING AS THE BOUNDARY LIFTS AWAY
FROM OUR REGION. FOLLOWING ITS DEPARTURE...GENERALLY DRY CONDITIONS
ARE EXPECTED FOR THE BALANCE OF TONIGHT...BEFORE THE TRAILING COLD
FRONT BRINGS MORE NUMEROUS SHOWERS AND THUNDERSTORMS AS IT PASSES
THROUGH THE REGION WEDNESDAY AFTERNOON AND NIGHT.
WHILE ANY OF THE SHOWERS/STORMS COULD PRODUCE LOCALLY HIGHER WINDS AND
WAVES OVER THE NEXT COUPLE OF DAYS...IN GENERAL LIGHT TO MODEST WINDS
WILL PREVAIL ACROSS THE LOWER LAKES REGION THROUGH WEDNESDAY NIGHT...
ALONG WITH WAVES OF UNDER 3 FEET.
FOLLOWING THE PASSAGE OF THE FRONT...HIGH PRESSURE IS EXPECTED TO
BUILD ACROSS THE REGION THURSDAY AND FRIDAY WHILE BRINGING A RETURN
TO MORE SETTLED CONDITIONS...ALONG WITH CONTINUED LIGHT TO MODEST
WINDS AND MINIMAL WAVES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JJR
NEAR TERM...JJR
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...JJR
MARINE...JJR
AREA FORECAST DISCUSSION
NWS BUFFALO NY
504 AM EDT TUE SEP 8 2015
.SYNOPSIS...
HIGH PRESSURE OVER THE MID ATLANTIC COAST WILL CONTINUE TO BRING
MIDSUMMERLIKE CONDITIONS TO THE REGION THROUGH THE FIRST HALF OF
WEDNESDAY...BEFORE A COLD FRONT CROSSES OUR REGION BETWEEN LATER
WEDNESDAY AND WEDNESDAY NIGHT. THIS FRONT WILL BE ACCOMPANIED BY
NUMEROUS SHOWERS AND THUNDERSTORMS AS IT PASSES THROUGH...AND WILL
BE FOLLOWED BY PROGRESSIVELY COOLER WEATHER DURING THE REMAINDER
OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 08Z...REGIONAL SURFACE OBSERVATIONS SUGGEST THAT THE WEAK
COLD FRONTAL BOUNDARY EXTENDS FROM THE SAINT LAWRENCE VALLEY
ACROSS NORTHERN LAKE ONTARIO TO THE GREATER TORONTO AREA...AND
THEN ON ACROSS SOUTHWESTERN ONTARIO. ALONG AND NEAR THIS
BOUNDARY...REGIONAL RADARS CONTINUE TO DEPICT AN ELONGATED SWATH
OF ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS.
DURING THE COURSE OF TODAY...THE WEAK COLD FRONT WILL BRIEFLY
STALL OUT ALONG OR SLIGHTLY NORTH OF OUR NORTHERN PERIPHERY THIS
MORNING... BEFORE LIFTING BACK NORTH THIS AFTERNOON AS A WARM
FRONT IN RESPONSE TO THE DEVELOPMENT OF BROAD LOW PRESSURE OVER
THE UPPER GREAT LAKES. ALONG AND NEAR THIS BOUNDARY...THERE WILL
BE A CONTINUED RISK OF SCATTERED SHOWERS AND THUNDERSTORMS THROUGH
THE DAY...WITH THIS RISK LYING ROUGHLY FROM THE NYS THRUWAY
CORRIDOR NORTHWARD THROUGH LATE THIS MORNING...THEN DIMINISHING
FROM SOUTHWEST TO NORTHEAST LATE THIS MORNING AND THIS AFTERNOON
AS THE FRONT BEGINS LIFTING BACK NORTH.
IN ADDITION TO ANY FRONTAL CONVECTION...THE COMBINATION OF
DIURNAL HEATING OF OUR VERY WARM AND HUMID AIRMASS AND
REDEVELOPING LAKE BREEZE BOUNDARIES MAY ALSO LEAD TO THE
DEVELOPMENT OF A SECOND REGION OF ISOLATED TO SCATTERED CONVECTION
ACROSS AREAS SOUTH OF LAKE ONTARIO THIS AFTERNOON...WITH THIS
PRIMARILY FOCUSED FROM INTERIOR PORTIONS OF THE SOUTHERN TIER AND
GENESEE VALLEY EASTWARD ACROSS THE FINGER LAKES.
WITH ALL OF THE ABOVE IN MIND...HAVE CONTINUED TO DEPICT A
GENERAL SOUTHWEST-NORTHEAST GRADIENT IN PRECIPITATION
PROBABILITIES FOR TODAY...WITH THESE RANGING FROM HIGH CHANCE
ACROSS THE SAINT LAWRENCE VALLEY AND NORTH COUNTRY...TO BELOW
SLIGHT CHANCE IN AN EXPECTED REGION OF LAKE SHADOWING IMMEDIATELY
EAST OF LAKE ERIE.
OUTSIDE OF THE AFOREMENTIONED CONVECTION...DRY WEATHER AND
MIDSUMMERLIKE WARMTH AND HUMIDITY SHOULD AGAIN PREVAIL ACROSS OUR
REGION TODAY. SURFACE DEWPOINTS WILL RANGE FROM THE LOWER 60S
ACROSS INTERIOR PORTIONS OF THE SOUTHERN TIER TO NEAR 70 ALONG THE
STALLED/RETREATING FRONTAL BOUNDARY...WHILE 850 MB TEMPS OF +16C
TO +19C WILL SUPPORT HIGH TEMPERATURES RANGING FROM THE LOWER 80S
ACROSS THE NORTH COUNTRY TO THE MID AND UPPER 80S ACROSS MOST OF
THE REST OF THE REGION...ALONG WITH SOME 90 DEGREE READINGS ACROSS
THE NORMAL WARM SPOTS OF THE GENESEE VALLEY/FINGER LAKES.
TONIGHT...THE WARM FRONT WILL FINISH LIFTING OFF TO OUR NORTH
EARLY IN THE EVENING. WITH THE DEPARTURE OF THIS FEATURE AND THE
LOSS OF DAYTIME HEATING...ANY LINGERING CONVECTION ACROSS THE
FINGER LAKES AND NORTH COUNTRY WILL COME TO AN END THIS
EVENING...LEAVING BEHIND LARGELY DRY WEATHER FOR THE BALANCE OF
THE NIGHTTIME HOURS AS OUR REGION WILL BE FIRMLY ENTRENCHED WITHIN
THE WARM SECTOR OF LOW PRESSURE LIFTING BY WELL TO OUR NORTHWEST.
THUS...WE CAN EXPECT YET ANOTHER UNSEASONABLY WARM NIGHT ACROSS
OUR REGION...WITH OVERNIGHT LOWS AGAIN RANGING FROM THE MID 60S
ACROSS INTERIOR PORTIONS OF THE SOUTHERN TIER TO THE LOWER 70S
ACROSS THE LAKE PLAINS...OR LEVELS THAT WILL BE NOT THAT FAR OFF
FROM NORMAL HIGH TEMPERATURES FOR EARLY SEPTEMBER.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
TEMPERATURES WILL RETURN TO NEAR NORMAL LEVELS ACROSS THE LOWER
GREAT LAKES DURING THIS PERIOD...AS THE UPPER LEVEL FLOW ACROSS
NORTH AMERICA WILL FEATURE AN AMPLIFYING TROUGH OVER THE EASTERN
HALF OF THE CONTINENT. THIS WILL BE SIGNIFICANT CHANGE FROM THE
FIRST WEEK OF SEPTEMBER WHEN A PERSISTENT SUB-TROPICAL RIDGE
DOMINATED THE EASTERN HALF OF THE COUNTRY. WHILE THE RIDGE WAS NOT
OVERLY IMPRESSIVE `ON PAPER`...ITS STAYING POWER FOR THIS TIME OF
YEAR ALLOWED FOR ANOMALOUSLY WARM AIR AND PLENTY OF GULF HUMIDITY
TO CREATE THE WARMEST STRETCH OF WEATHER OUR REGION EXPERIENCED
ALL SUMMER. WITH THE PASSING OF THE LAST SUMMER HOLIDAY...MOTHER
NATURE WILL ALSO TURN THE PAGE...ALBEIT IT SLOWLY.
AS IS SO OFTEN IS THE CASE...A STRONG LATITUDINAL H25 JET
CROSSING THE NORTHERN PACIFIC WILL PLOW ACROSS THE CANADIAN
ROCKIES AND ESTABLISH A BROAD DOWNSTREAM TROUGH OVER THE EASTERN
HALF OF THE CONTINENT. THIS TROUGH WILL FLATTEN THE PERTINACIOUS
SUB TROPICAL RIDGE...AND IN TIME WILL DIRECT PROGRESSIVELY COOLER
CANADIAN AIR SOUTHWARDS ACROSS THE LOWER 48. THIS COOLING WILL
INITIALLY ONLY TAKE OUR TEMPERATURES BACK TOWARDS NORMAL...BUT AS
WE HEAD IN TO THE WEEKEND...WE COULD EXPERIENCE A DAY OR TWO OF
FALL LIKE CONDITIONS.
AN INVERTED SFC TROUGH EXTENDING FROM THE UPPER GREAT LAKES TO
THE CENTRAL PLAINS LATE TUESDAY NIGHT WILL GRADUALLY EVOLVE INTO A
LEGITIMATE...ALBEIT WAVY...COLD FRONT ON WEDNESDAY AS IT WILL PUSH
SOUTHEAST ACROSS THE LOWER GREAT LAKES. THE OVERALL SYNOPTIC
FORCING WITH THE SLOW MOVING FRONTAL BOUNDARY IS NOT BEING
ADVERTISED AS BEING ALL THAT IMPRESSIVE...BUT IT WILL BE ENOUGH IN
COMBINATION WITH THE MID SUMMER LIKE THERMODYNAMIC ENVIRONMENT TO
PRODUCE INCREASINGLY NUMEROUS SHOWERS AND POTENTIALLY STRONG
THUNDERSTORMS.
ADDRESSING THE FORMER FIRST...AS EARLIER MENTIONED THE FRONTAL
BOUNDARY WILL STILL BE TAKING SHAPE DURING THE DAY WEDNESDAY AS IT
WILL BE PUSHING INTO OUR FORECAST AREA. TRUE FRONTOGENETIC FORCING
FROM THE FRONT WILL THUS BE GENERALLY WEAK...ALTHOUGH HGT FALLS
AND A 120KT H25 JET OVER NORTHERN QUEBEC WILL ADD SOME LARGE SCALE
SYNOPTIC LIFT BY PLACING OUR FORECAST AREA UNDER RR QUAD OF THE
JET ENTRANCE REGION. THERMODYNAMICALLY...OUR WARM HUMID AIRMASS
WILL ALREADY BE UNSTABLE. SBCAPES WILL ALREADY BE IN THE HUNDREDS
AS WE OPEN THE DAY...AND DIMINISHING MORNING SUNSHINE WILL ONLY
ADD TO THIS INSTABILITY...PARTICULARLY OVER PARTS OF THE SRN TIER
AND FINGER LAKES REGIONS WHERE MUCAPES COULD APPROACH 2000 J/KG.
MEANWHILE A SWATH OF TROPICAL MOISTURE TO THE TUNE OF 2 INCH PWAT
VALUES WILL STREAM ACROSS OUR REGION ALONG AND AHEAD OF THE SFC
BOUNDARY...SO THIS IN COMBINATION WITH THE SYNOPTIC FORCING AND
INSTABILITY COULD RESULT IN TORRENTIAL DOWNPOURS WITH SOME OF THE
CONVECTION. FORTUNATELY...THE REGION IS PARCHED FROM A GENERAL
LACK OF RAINFALL FROM THE PAST MONTH OR SO...AND GUIDANCE IS
SUGGESTING THAT CORFIDI VECTORS WILL LENGTHEN AS THE FRONT
APPROACHES. THIS WILL LESSEN THE RISK FOR WIDESPREAD HYDRO RELATED
PROBLEMS...BUT LOCAL ISSUES WILL STILL HAVE TO BE ADDRESSED GIVEN
THE SUB TROPICAL ENVIRONMENT. THE MENTION OF TORRENTIAL DOWNPOURS
HAS ALREADY BEEN ADDED TO THE HWO PRODUCT AND TO THE GRIDDED DATA
BASE...SO WILL CONTINUE.
ALONG WITH THE THREAT FOR LOCALLY HEAVY CONVECTIVE RAINS...THERE
WILL BE AN ISOLATED RISK FOR STRONG THUNDERSTORMS. THIS POTENTIAL
WILL BE ATTENUATED BY UNIMPRESSIVE MID LEVEL LAPSE RATES UNDER 6
DEG C/KM...BUT GIVEN BULK SHEAR VALUES OF 35 TO 40 KNOTS AND THE
UNCERTAINTY AS TO HOW MUCH SUNSHINE PARTS OF THE REGION RECEIVE...
WE WILL CONTINUE TO HIGHLIGHT THE CHANCE FOR GUSTY CONVECTIVE
WINDS.
CONSIDERING ALL OF THE ABOVE...WEDNESDAY SHOULD START OFF DRY
ACROSS OUR FORECAST AREA...BUT AS THE FRONT NEARS DURING THE
MIDDAY...CONVECTION WILL BEGIN TO BREAK OUT. THIS MAY BE HASTENED
ACROSS PARTS OF THE SRN TIER AND FINGER LAKES REGION WHERE A LAKE
BREEZE BOUNDARY COULD FOCUS AN INITIAL ROUND OF STORMS...THEN AS
THE FRONT SLOWLY CROSSES THE LOWER GREAT LAKES IN THE AFTERNOON
AND EVENING...THE GENERAL CONDITIONS WILL FURTHER DETERIORATE.
WILL MAINTAIN LIKELY POPS REGIONWIDE FOR THE LATE AFTERNOON.
OTHERWISE...WEDNESDAY WILL BE WARM AND HUMID WITH MAX TEMPS
RANGING FROM THE LOWER 80S OVER THE FAR WEST TO THE MID AND
POSSIBLY UPPER 80S ACROSS PARTS OF THE FINGER LAKES.
DURING THE COURSE OF WEDNESDAY NIGHT...THE FRONTAL BOUNDARY WILL
LAZILY CROSS OUR FORECAST AREA AS UPSTREAM SFC WAVES WILL RETARD
ITS FORWARD PROGRESS. THIS IS THE TIME PERIOD WHERE THE AXIS OF
THE DEEPEST MOISTURE WILL CROSS OUR FORECAST AREA. WHILE DIURNALLY
ENHANCED INSTABILITY WILL BE WANING...THE PASSAGE OF ANY WAVES
ALONG THE FRONTAL BOUNDARY COULD SYNOPTICALLY ENHANCE ANY SHOWERS
INTO A 2 TO THREE HOUR PERIOD OF STEADIER RAIN. THIS POTENTIAL
WILL BE GREATEST OVER THE SRN TIER AND FINGER LAKES REGION.
AGAIN...WE WILL BE FORTUNATE IN THAT WE HAVE VERY DRY ANTECEDENT
CONDITIONS.
ON THURSDAY...WEAK HIGH PRESSURE OVER LOWER MICHIGAN WILL
GRADUALLY BUILD ACROSS OUR FORECAST AREA WHILE THE FLEXUOUS
FRONTAL BOUNDARY WILL MAKE ITS WAY TO THE EAST COAST. SHOWERS...
THAT WILL BE MOST LIKELY EAST OF LINE FROM ROCHESTER TO
JAMESTOWN...WILL TAPER OFF FROM WEST TO EAST IN THE PROCESS.
SUNSHINE SHOULD RETURN IN FORCE TO THE NIAGARA FRONTIER AND PARTS
OF THE SRN TIER BY THE AFTERNOON...BUT THE IMPROVEMENT WILL TAKE
LONGER FURTHER EAST. IT WILL START TO FEEL MUCH MORE COMFORTABLE
AS WELL...AS THE FRESH AIRMASS WILL START TO SETTLE OVER THE
REGION WITH DEW POINTS OVER THE WESTERN COUNTIES STEADIER FALLING
THROUGH THE 50S. AFTER NEARLY TWO WEEKS OF AFTERNOON TEMPERATURES
IN THE 80S...MAX TEMPS ON THURSDAY SHOULD FINALLY RETURN TO THE
70S.
THE GRADUAL CLEARING PROCESS WILL CONTINUE THURSDAY NIGHT AS THE
LEADING EDGE OF HIGH PRESSURE WILL WORK ACROSS OUR FORECAST AREA.
ANY LEFTOVER SHOWERS OVER EASTERN SECTIONS SHOULD END DURING THE
EVENING WITH MUCH MORE COMFORTABLE SLEEPING CONDITIONS GAINING A
FOOTHOLD OVER THE ENTIRE FORECAST AREA. OVERNIGHT LOWS WILL
GENERALLY BE IN THE 50S...WITH THE RADIATIONAL COOLING PROBABLY
LEADING TO SOME VALLEY FOG ACROSS PARTS OF THE SRN TIER AND FINGER
LAKES REGIONS.
WHILE PLEASANT WEATHER IS EXPECTED ACROSS OUR REGION ON FRIDAY...
A MID LEVEL DISTURBANCE DIGGING INTO THE GREAT LAKES LONGWAVE
TROUGH WILL ENCOURAGE SOME `BAGGINESS` IN THE SFC PRESSURE FIELD
ACROSS THE UPPER OHIO VALLEY. THIS WILL BE THE BEGINNINGS OF WHAT
COULD POTENTIALLY BE A CLOSED LOW FOR OUR REGION DURING THE
UPCOMING WEEKEND. MORE ON THIS LOW CONFIDENCE EVENT IN THE LONG
TERM SECTION BELOW. GENERALLY PARTLY SUNNY SKIES CAN BE EXPECTED
ON FRIDAY WITH AFTERNOON TEMPERATURES IN THE 70S BEING ACCOMPANIED
BY COMFORTABLY LOW HUMIDITY LEVELS.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
ONCE AGAIN...THE MEDIUM RANGE GUIDANCE PACKAGES ARE VASTLY
DIFFERENT IN THEIR SOLUTIONS OVER THE LOWER GREAT LAKES IN THE
DAYS 5-7 PERIOD. BOTH THE GFS AND ECMWF OPERATIONAL MODELS ARE
STUBBORNLY HOLDING ONTO THE SAME SCENARIOS THAT THEY HAVE BEEN
PREACHING FOR THE PAST COUPLE DAYS... WITH THE LATTER DEPICTING
THE DEVELOPMENT OF A STACKED STORM SYSTEM OVER SOUTHERN ONTARIO
AND THE LOWER GREAT LAKES. NEEDLESS TO SAY...THIS WOULD BE A VERY
UNSETTLED SOLUTION FOR OUR FORECAST AREA WITH FAIRLY WIDESPREAD
FREQUENT SHOWERS.
BECAUSE OF THE DISPARITY WITHIN THE GUIDANCE PACKAGES...HAVE NO
CHOICE BUT TO KEEP THE LOW/SLGT CHC BROADBRUSH POPS THAT ARE IN
CONTINUITY IN PLACE THROUGH AT LEAST THE WEEKEND.
&&
.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
A WEAK COLD FRONT WILL BRIEFLY STALL OUT ALONG OR SLIGHTLY NORTH
OF OUR NORTHERN PERIPHERY THIS MORNING...BEFORE LIFTING BACK NORTH
THIS AFTERNOON AS A WARM FRONT IN RESPONSE TO THE DEVELOPMENT OF
BROAD LOW PRESSURE OVER THE UPPER GREAT LAKES. THERE WILL BE A
CONTINUED RISK OF SCATTERED SHOWERS/THUNDERSTORMS AND ATTENDANT
BRIEF LOCALIZED RESTRICTIONS ALONG AND NEAR THIS BOUNDARY THROUGH
THE DAY...AND ALSO ALONG AND INLAND FROM A DEVELOPING LAKE ERIE
LAKE BREEZE BOUNDARY DURING THE AFTERNOON. OUTSIDE OF ANY SUCH
CONVECTION AND ANY EARLY MORNING SOUTHERN TIER VALLEY FOG...VFR
CONDITIONS SHOULD OTHERWISE PREVAIL.
TONIGHT...THE FRONTAL BOUNDARY WILL FINISH LIFTING OFF TO OUR
NORTH EARLY IN THE EVENING. WITH THE DEPARTURE OF THIS FEATURE AND
THE LOSS OF DAYTIME HEATING...ANY LINGERING CONVECTION/ATTENDANT
RESTRICTIONS ACROSS THE FINGER LAKES AND NORTH COUNTRY WILL COME
TO AN END THIS EVENING...LEAVING BEHIND LARGELY DRY/VFR CONDITIONS
FOR THE BALANCE OF THE NIGHTTIME HOURS.
OUTLOOK...
WEDNESDAY...MAINLY VFR INITIALLY...THEN SHOWERS AND THUNDERSTORMS
WITH ATTENDANT REDUCTIONS TO IFR/MVFR BECOMING LIKELY FOR WEDNESDAY
AFTERNOON AND EVENING.
THURSDAY...SCATTERED TO NUMEROUS SHOWERS TAPERING OFF WITH CONDITIONS
IMPROVING TO VFR.
FRIDAY...MAINLY VFR...EXCEPT IN POSSIBLE MORNING SOUTHERN TIER
VALLEY FOG.
SATURDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
HIGH PRESSURE CENTERED OVER THE MID ATLANTIC COASTLINE WILL SLOWLY
DRIFT OFFSHORE THROUGH MIDWEEK. A STALLED OUT COLD FRONT DRAPED FROM
THE SAINT LAWRENCE VALLEY SOUTHWESTWARD ACROSS LAKE ONTARIO WILL LIFT
BACK NORTH OF THE REGION AS A WARM FRONT THIS AFTERNOON AND EVENING
IN RESPONSE TO DEVELOPING LOW PRESSURE ACROSS THE UPPER GREAT LAKES...
THEN THIS LATTER FEATURE WILL SLOWLY EASE ITS TRAILING COLD FRONT
ACROSS THE AREA WEDNESDAY AFTERNOON AND NIGHT.
THE INITIAL FRONTAL BOUNDARY WILL CONTINUE TO TRIGGER SCATTERED
SHOWERS AND THUNDERSTORMS AS IT LINGERS NEAR THE LOWER GREAT LAKES
THIS MORNING...WITH THESE THEN GRADUALLY DIMINISHING FROM SOUTHWEST
TO NORTHEAST THIS AFTERNOON AND EVENING AS THE BOUNDARY LIFTS AWAY
FROM OUR REGION. FOLLOWING ITS DEPARTURE...GENERALLY DRY CONDITIONS
ARE EXPECTED FOR THE BALANCE OF TONIGHT...BEFORE THE TRAILING COLD
FRONT BRINGS MORE NUMEROUS SHOWERS AND THUNDERSTORMS AS IT PASSES
THROUGH THE REGION WEDNESDAY AFTERNOON AND NIGHT.
WHILE ANY OF THE SHOWERS/STORMS COULD PRODUCE LOCALLY HIGHER WINDS AND
WAVES OVER THE NEXT COUPLE OF DAYS...IN GENERAL LIGHT TO MODEST WINDS
WILL PREVAIL ACROSS THE LOWER LAKES REGION THROUGH WEDNESDAY NIGHT...
ALONG WITH WAVES OF UNDER 3 FEET.
FOLLOWING THE PASSAGE OF THE FRONT...HIGH PRESSURE IS EXPECTED TO
BUILD ACROSS THE REGION THURSDAY AND FRIDAY WHILE BRINGING A RETURN
TO MORE SETTLED CONDITIONS...ALONG WITH CONTINUED LIGHT TO MODEST
WINDS AND MINIMAL WAVES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JJR
NEAR TERM...JJR
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...JJR
MARINE...JJR
AREA FORECAST DISCUSSION
NWS BUFFALO NY
414 AM EDT TUE SEP 8 2015
.SYNOPSIS...
HIGH PRESSURE OVER THE MID ATLANTIC COAST WILL CONTINUE TO BRING
MIDSUMMERLIKE CONDITIONS TO THE REGION THROUGH THE FIRST HALF OF
WEDNESDAY...BEFORE A COLD FRONT CROSSES OUR REGION BETWEEN LATER
WEDNESDAY AND WEDNESDAY NIGHT. THIS FRONT WILL BE ACCOMPANIED BY
NUMEROUS SHOWERS AND THUNDERSTORMS AS IT PASSES THROUGH...AND WILL
BE FOLLOWED BY PROGRESSIVELY COOLER WEATHER DURING THE REMAINDER
OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 08Z...REGIONAL SURFACE OBSERVATIONS SUGGEST THAT THE WEAK
COLD FRONTAL BOUNDARY EXTENDS FROM THE SAINT LAWRENCE VALLEY
ACROSS NORTHERN LAKE ONTARIO TO THE GREATER TORONTO AREA...AND
THEN ON ACROSS SOUTHWESTERN ONTARIO. ALONG AND NEAR THIS
BOUNDARY...REGIONAL RADARS CONTINUE TO DEPICT AN ELONGATED SWATH
OF ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS.
DURING THE COURSE OF TODAY...THE WEAK COLD FRONT WILL BRIEFLY
STALL OUT ALONG OR SLIGHTLY NORTH OF OUR NORTHERN PERIPHERY THIS
MORNING... BEFORE LIFTING BACK NORTH THIS AFTERNOON AS A WARM
FRONT IN RESPONSE TO THE DEVELOPMENT OF BROAD LOW PRESSURE OVER
THE UPPER GREAT LAKES. ALONG AND NEAR THIS BOUNDARY...THERE WILL
BE A CONTINUED RISK OF SCATTERED SHOWERS AND THUNDERSTORMS THROUGH
THE DAY...WITH THIS RISK LYING ROUGHLY FROM THE NYS THRUWAY
CORRIDOR NORTHWARD THROUGH LATE THIS MORNING...THEN DIMINISHING
FROM SOUTHWEST TO NORTHEAST LATE THIS MORNING AND THIS AFTERNOON
AS THE FRONT BEGINS LIFTING BACK NORTH.
IN ADDITION TO ANY FRONTAL CONVECTION...THE COMBINATION OF
DIURNAL HEATING OF OUR VERY WARM AND HUMID AIRMASS AND
REDEVELOPING LAKE BREEZE BOUNDARIES MAY ALSO LEAD TO THE
DEVELOPMENT OF A SECOND REGION OF ISOLATED TO SCATTERED CONVECTION
ACROSS AREAS SOUTH OF LAKE ONTARIO THIS AFTERNOON...WITH THIS
PRIMARILY FOCUSED FROM INTERIOR PORTIONS OF THE SOUTHERN TIER AND
GENESEE VALLEY EASTWARD ACROSS THE FINGER LAKES.
WITH ALL OF THE ABOVE IN MIND...HAVE CONTINUED TO DEPICT A
GENERAL SOUTHWEST-NORTHEAST GRADIENT IN PRECIPITATION
PROBABILITIES FOR TODAY...WITH THESE RANGING FROM HIGH CHANCE
ACROSS THE SAINT LAWRENCE VALLEY AND NORTH COUNTRY...TO BELOW
SLIGHT CHANCE IN AN EXPECTED REGION OF LAKE SHADOWING IMMEDIATELY
EAST OF LAKE ERIE.
OUTSIDE OF THE AFOREMENTIONED CONVECTION...DRY WEATHER AND
MIDSUMMERLIKE WARMTH AND HUMIDITY SHOULD AGAIN PREVAIL ACROSS OUR
REGION TODAY. SURFACE DEWPOINTS WILL RANGE FROM THE LOWER 60S
ACROSS INTERIOR PORTIONS OF THE SOUTHERN TIER TO NEAR 70 ALONG THE
STALLED/RETREATING FRONTAL BOUNDARY...WHILE 850 MB TEMPS OF +16C
TO +19C WILL SUPPORT HIGH TEMPERATURES RANGING FROM THE LOWER 80S
ACROSS THE NORTH COUNTRY TO THE MID AND UPPER 80S ACROSS MOST OF
THE REST OF THE REGION...ALONG WITH SOME 90 DEGREE READINGS ACROSS
THE NORMAL WARM SPOTS OF THE GENESEE VALLEY/FINGER LAKES.
TONIGHT...THE WARM FRONT WILL FINISH LIFTING OFF TO OUR NORTH
EARLY IN THE EVENING. WITH THE DEPARTURE OF THIS FEATURE AND THE
LOSS OF DAYTIME HEATING...ANY LINGERING CONVECTION ACROSS THE
FINGER LAKES AND NORTH COUNTRY WILL COME TO AN END THIS
EVENING...LEAVING BEHIND LARGELY DRY WEATHER FOR THE BALANCE OF
THE NIGHTTIME HOURS AS OUR REGION WILL BE FIRMLY ENTRENCHED WITHIN
THE WARM SECTOR OF LOW PRESSURE LIFTING BY WELL TO OUR NORTHWEST.
THUS...WE CAN EXPECT YET ANOTHER UNSEASONABLY WARM NIGHT ACROSS
OUR REGION...WITH OVERNIGHT LOWS AGAIN RANGING FROM THE MID 60S
ACROSS INTERIOR PORTIONS OF THE SOUTHERN TIER TO THE LOWER 70S
ACROSS THE LAKE PLAINS...OR LEVELS THAT WILL BE NOT THAT FAR OFF
FROM NORMAL HIGH TEMPERATURES FOR EARLY SEPTEMBER.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
TEMPERATURES WILL RETURN TO NEAR NORMAL LEVELS ACROSS THE LOWER
GREAT LAKES DURING THIS PERIOD...AS THE UPPER LEVEL FLOW ACROSS
NORTH AMERICA WILL FEATURE AN AMPLIFYING TROUGH OVER THE EASTERN
HALF OF THE CONTINENT. THIS WILL BE SIGNIFICANT CHANGE FROM THE
FIRST WEEK OF SEPTEMBER WHEN A PERSISTENT SUB-TROPICAL RIDGE
DOMINATED THE EASTERN HALF OF THE COUNTRY. WHILE THE RIDGE WAS NOT
OVERLY IMPRESSIVE `ON PAPER`...ITS STAYING POWER FOR THIS TIME OF
YEAR ALLOWED FOR ANOMALOUSLY WARM AIR AND PLENTY OF GULF HUMIDITY
TO CREATE THE WARMEST STRETCH OF WEATHER OUR REGION EXPERIENCED
ALL SUMMER. WITH THE PASSING OF THE LAST SUMMER HOLIDAY...MOTHER
NATURE WILL ALSO TURN THE PAGE...ALBEIT IT SLOWLY.
AS IS SO OFTEN IS THE CASE...A STRONG LATITUDINAL H25 JET
CROSSING THE NORTHERN PACIFIC WILL PLOW ACROSS THE CANADIAN
ROCKIES AND ESTABLISH A BROAD DOWNSTREAM TROUGH OVER THE EASTERN
HALF OF THE CONTINENT. THIS TROUGH WILL FLATTEN THE PERTINACIOUS
SUB TROPICAL RIDGE...AND IN TIME WILL DIRECT PROGRESSIVELY COOLER
CANADIAN AIR SOUTHWARDS ACROSS THE LOWER 48. THIS COOLING WILL
INITIALLY ONLY TAKE OUR TEMPERATURES BACK TOWARDS NORMAL...BUT AS
WE HEAD IN TO THE WEEKEND...WE COULD EXPERIENCE A DAY OR TWO OF
FALL LIKE CONDITIONS.
AN INVERTED SFC TROUGH EXTENDING FROM THE UPPER GREAT LAKES TO
THE CENTRAL PLAINS LATE TUESDAY NIGHT WILL GRADUALLY EVOLVE INTO A
LEGITIMATE...ALBEIT WAVY...COLD FRONT ON WEDNESDAY AS IT WILL PUSH
SOUTHEAST ACROSS THE LOWER GREAT LAKES. THE OVERALL SYNOPTIC
FORCING WITH THE SLOW MOVING FRONTAL BOUNDARY IS NOT BEING
ADVERTISED AS BEING ALL THAT IMPRESSIVE...BUT IT WILL BE ENOUGH IN
COMBINATION WITH THE MID SUMMER LIKE THERMODYNAMIC ENVIRONMENT TO
PRODUCE INCREASINGLY NUMEROUS SHOWERS AND POTENTIALLY STRONG
THUNDERSTORMS.
ADDRESSING THE FORMER FIRST...AS EARLIER MENTIONED THE FRONTAL
BOUNDARY WILL STILL BE TAKING SHAPE DURING THE DAY WEDNESDAY AS IT
WILL BE PUSHING INTO OUR FORECAST AREA. TRUE FRONTOGENETIC FORCING
FROM THE FRONT WILL THUS BE GENERALLY WEAK...ALTHOUGH HGT FALLS
AND A 120KT H25 JET OVER NORTHERN QUEBEC WILL ADD SOME LARGE SCALE
SYNOPTIC LIFT BY PLACING OUR FORECAST AREA UNDER RR QUAD OF THE
JET ENTRANCE REGION. THERMODYNAMICALLY...OUR WARM HUMID AIRMASS
WILL ALREADY BE UNSTABLE. SBCAPES WILL ALREADY BE IN THE HUNDREDS
AS WE OPEN THE DAY...AND DIMINISHING MORNING SUNSHINE WILL ONLY
ADD TO THIS INSTABILITY...PARTICULARLY OVER PARTS OF THE SRN TIER
AND FINGER LAKES REGIONS WHERE MUCAPES COULD APPROACH 2000 J/KG.
MEANWHILE A SWATH OF TROPICAL MOISTURE TO THE TUNE OF 2 INCH PWAT
VALUES WILL STREAM ACROSS OUR REGION ALONG AND AHEAD OF THE SFC
BOUNDARY...SO THIS IN COMBINATION WITH THE SYNOPTIC FORCING AND
INSTABILITY COULD RESULT IN TORRENTIAL DOWNPOURS WITH SOME OF THE
CONVECTION. FORTUNATELY...THE REGION IS PARCHES FROM A GENERAL
LACK OF RAINFALL FROM THE PAST MONTH OR SO...AND GUIDANCE IS
SUGGESTING THAT CORFIDI VECTORS WILL LENGTHEN AS THE FRONT
APPROACHES. THIS WILL LESSEN THE RISK FOR WIDESPREAD HYDRO RELATED
PROBLEMS...BUT LOCAL ISSUES WILL STILL HAVE TO BE ADDRESSED GIVEN
THE SUB TROPICAL ENVIRONMENT. THE MENTION OF TORRENTIAL DOWNPOURS
HAS ALREADY BEEN ADDED TO THE HWO PRODUCE AND TO THE GRIDDED DATA
BASE...SO WILL CONTINUE.
ALONG WITH THE THREAT FOR LOCALLY HEAVY CONVECTIVE RAINS...THERE
WILL BE AN ISOLATED RISK FOR STRONG THUNDERSTORMS. THIS POTENTIAL
WILL BE ATTENUATED BY UNIMPRESSIVE MID LEVEL LAPSE RATES UNDER 6
DEG C/KM...BUT GIVEN BULK SHEAR VALUES OF 35 TO 40 KNOTS AND THE
UNCERTAINTY AS TO HOW MUCH SUNSHINE PARTS OF THE REGION RECEIVE...
WE WILL CONTINUE TO HIGHLIGHT THE CHANCE FOR GUSTY CONVECTIVE
WINDS.
CONSIDERING ALL OF THE ABOVE...WEDNESDAY SHOULD START OFF DRY
ACROSS OUR FORECAST AREA...BUT AS THE FRONT NEARS DURING THE
MIDDAY... CONVECTION WILL BEGIN TO BREAK OUT. THIS MAY BE HASTENED
ACROSS PARTS OF THE SRN TIER AND FINGER LAKES REGION WHERE A LAKE
BREEZE BOUNDARY COULD FOCUS AN INITIAL ROUND OF STORMS...THEN AS
THE FRONT SLOWLY CROSSES THE LOWER GREAT LAKES IN THE AFTERNOON
AND EVENING... THE GENERAL CONDITIONS WILL FURTHER DETERIORATE.
WILL MAINTAIN LIKELY POPS REGIONWIDE FOR THE LATE AFTERNOON.
OTHERWISE...WEDNESDAY WILL BE WARM AND HUMID WITH MAX TEMPS
RANGING FROM THE LOWER 80S OVER THE FAR WEST TO THE MID AND
POSSIBLY UPPER 80S ACROSS PARTS OF THE FINGER LAKES.
DURING THE COURSE OF WEDNESDAY NIGHT...THE FRONTAL BOUNDARY WILL
LAZILY CROSS OUR FORECAST AREA AS UPSTREAM SFC WAVES WILL RETARD
ITS FORWARD PROGRESS. THIS IS THE TIME PERIOD WHERE THE AXIS OF
THE DEEPEST MOISTURE WILL CROSS OUR FORECAST AREA. WHILE DIURNALLY
ENHANCED INSTABILITY WILL BE WANING...THE PASSAGE OF ANY WAVES
ALONG THE FRONTAL BOUNDARY COULD SYNOPTICALLY ENHANCE ANY SHOWERS
INTO A 2 TO THREE HOUR PERIOD OF STEADIER RAIN. THIS POTENTIAL
WILL BE GREATEST OVER THE SRN TIER AND FINGER LAKES REGION.
AGAIN...WE WILL BE FORTUNATE IN THAT WE HAVE VERY DRY ANTECEDENT
CONDITIONS.
ON THURSDAY...WEAK HIGH PRESSURE OVER LOWER MICHIGAN WILL
GRADUALLY BUILD ACROSS OUR FORECAST AREA WHILE THE FLEXUOUS
FRONTAL BOUNDARY WILL MAKE ITS WAY TO THE EAST COAST. SHOWERS...
THAT WILL BE MOST LIKELY EAST OF LINE FROM ROCHESTER TO
JAMESTOWN...WILL TAPER OFF FROM WEST TO EAST IN THE PROCESS.
SUNSHINE SHOULD RETURN IN FORCE TO THE NIAGARA FRONTIER AND PARTS
OF THE SRN TIER BY THE AFTERNOON... BUT THE IMPROVEMENT WILL TAKE
LONGER FURTHER EAST. IT WILL START TO FEEL MUCH MORE COMFORTABLE
AS WELL...AS THE FRESH AIRMASS WILL START TO SETTLE OVER THE
REGION WITH DEW POINTS OVER THE WESTERN COUNTIES STEADIER FALLING
THROUGH THE 50S. AFTER NEARLY TWO WEEKS OF AFTERNOON TEMPERATURES
IN THE 80S...MAX TEMPS ON THURSDAY SHOULD FINALLY RETURN TO THE
70S.
THE GRADUAL CLEARING PROCESS WILL CONTINUE THURSDAY NIGHT AS THE
LEADING EDGE OF HIGH PRESSURE WILL WORK ACROSS OUR FORECAST AREA.
ANY LEFTOVER SHOWERS OVER EASTERN SECTIONS SHOULD END DURING THE
EVENING WITH MUCH MORE COMFORTABLE SLEEPING CONDITIONS GAINING A
FOOTHOLD OVER THE ENTIRE FORECAST AREA. OVERNIGHT LOWS WILL
GENERALLY BE IN THE 50S...WITH THE RADIATIONAL COOLING PROBABLY
LEADING TO SOME VALLEY FOG ACROSS PARTS OF THE SRN TIER AND FINGER
LAKES REGIONS.
WHILE PLEASANT WEATHER IS EXPECTED ACROSS OUR REGION ON FRIDAY...
A MID LEVEL DISTURBANCE DIGGING INTO THE GREAT LAKES LONGWAVE
TROUGH WILL ENCOURAGE SOME `BAGGINESS` IN THE SFC PRESSURE FIELD
ACROSS THE UPPER OHIO VALLEY. THIS WILL BE THE BEGINNINGS OF WHAT
COULD POTENTIALLY BE A CLOSED LOW FOR OUR REGION DURING THE
UPCOMING WEEKEND. MORE ON THIS LOW CONFIDENCE EVENT IN THE LONG
TERM SECTION BELOW. GENERALLY PARTLY SUNNY SKIES CAN BE EXPECTED
ON FRIDAY WITH AFTERNOON TEMPERATURES IN THE 70S BEING ACCOMPANIED
BY COMFORTABLY LOW HUMIDITY LEVELS.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
ONCE AGAIN...THE MEDIUM RANGE GUIDANCE PACKAGES ARE VASTLY
DIFFERENT IN THEIR SOLUTIONS OVER THE LOWER GREAT LAKES IN THE
DAYS 5-7 PERIOD. BOTH THE GFS AND ECMWF OPERATIONAL MODELS ARE
STUBBORNLY HOLDING ONTO THE SAME SCENARIOS THAT THEY HAVE BEEN
PREACHING FOR THE PAST COUPLE DAYS... WITH THE LATTER DEPICTING
THE DEVELOPMENT OF A STACKED STORM SYSTEM OVER SOUTHERN ONTARIO
AND THE LOWER GREAT LAKES. NEEDLESS TO SAY...THIS WOULD BE A VERY
UNSETTLED SOLUTION FOR OUR FORECAST AREA WITH FAIRLY WIDESPREAD
FREQUENT SHOWERS.
BECAUSE OF THE DISPARITY WITHIN THE GUIDANCE PACKAGES...HAVE NO
CHOICE BUT TO KEEP THE LOW/SLGT CHC BROADBRUSH POPS THAT ARE IN
CONTINUITY IN PLACE THROUGH AT LEAST THE WEEKEND.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
A WEAK COLD FRONT WILL BRIEFLY STALL OUT ALONG OR SLIGHTLY NORTH
OF OUR NORTHERN PERIPHERY THIS MORNING...BEFORE LIFTING BACK NORTH
THIS AFTERNOON AS A WARM FRONT IN RESPONSE TO THE DEVELOPMENT OF
BROAD LOW PRESSURE OVER THE UPPER GREAT LAKES. THERE WILL BE A
CONTINUED RISK OF SCATTERED SHOWERS/THUNDERSTORMS AND ATTENDANT
BRIEF LOCALIZED RESTRICTIONS ALONG AND NEAR THIS BOUNDARY THROUGH
THE DAY...AND ALSO ALONG AND INLAND FROM A DEVELOPING LAKE ERIE
LAKE BREEZE BOUNDARY DURING THE AFTERNOON. OUTSIDE OF ANY SUCH
CONVECTION AND ANY EARLY MORNING SOUTHERN TIER VALLEY FOG...VFR
CONDITIONS SHOULD OTHERWISE PREVAIL.
TONIGHT...THE FRONTAL BOUNDARY WILL FINISH LIFTING OFF TO OUR
NORTH EARLY IN THE EVENING. WITH THE DEPARTURE OF THIS FEATURE AND
THE LOSS OF DAYTIME HEATING...ANY LINGERING CONVECTION/ATTENDANT
RESTRICTIONS ACROSS THE FINGER LAKES AND NORTH COUNTRY WILL COME
TO AN END THIS EVENING...LEAVING BEHIND LARGELY DRY/VFR CONDITIONS
FOR THE BALANCE OF THE NIGHTTIME HOURS.
OUTLOOK...
WEDNESDAY...MAINLY VFR INITIALLY...THEN SHOWERS AND THUNDERSTORMS
WITH ATTENDANT REDUCTIONS TO IFR/MVFR BECOMING LIKELY FOR WEDNESDAY
AFTERNOON AND EVENING.
THURSDAY...SCATTERED TO NUMEROUS SHOWERS TAPERING OFF WITH CONDITIONS
IMPROVING TO VFR.
FRIDAY...MAINLY VFR...EXCEPT IN POSSIBLE MORNING SOUTHERN TIER
VALLEY FOG.
SATURDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
HIGH PRESSURE CENTERED OVER THE MID ATLANTIC COASTLINE WILL SLOWLY
DRIFT OFFSHORE THROUGH MIDWEEK. A STALLED OUT COLD FRONT DRAPED FROM
THE SAINT LAWRENCE VALLEY SOUTHWESTWARD ACROSS LAKE ONTARIO WILL LIFT
BACK NORTH OF THE REGION AS A WARM FRONT THIS AFTERNOON AND EVENING
IN RESPONSE TO DEVELOPING LOW PRESSURE ACROSS THE UPPER GREAT LAKES...
THEN THIS LATTER FEATURE WILL SLOWLY EASE ITS TRAILING COLD FRONT
ACROSS THE AREA WEDNESDAY AFTERNOON AND NIGHT.
THE INITIAL FRONTAL BOUNDARY WILL CONTINUE TO TRIGGER SCATTERED
SHOWERS AND THUNDERSTORMS AS IT LINGERS NEAR THE LOWER GREAT LAKES
THIS MORNING...WITH THESE THEN GRADUALLY DIMINISHING FROM SOUTHWEST
TO NORTHEAST THIS AFTERNOON AND EVENING AS THE BOUNDARY LIFTS AWAY
FROM OUR REGION. FOLLOWING ITS DEPARTURE...GENERALLY DRY CONDITIONS
ARE EXPECTED FOR THE BALANCE OF TONIGHT...BEFORE THE TRAILING COLD
FRONT BRINGS MORE NUMEROUS SHOWERS AND THUNDERSTORMS AS IT PASSES
THROUGH THE REGION WEDNESDAY AFTERNOON AND NIGHT.
WHILE ANY OF THE SHOWERS/STORMS COULD PRODUCE LOCALLY HIGHER WINDS AND
WAVES OVER THE NEXT COUPLE OF DAYS...IN GENERAL LIGHT TO MODEST WINDS
WILL PREVAIL ACROSS THE LOWER LAKES REGION THROUGH WEDNESDAY NIGHT...
ALONG WITH WAVES OF UNDER 3 FEET.
FOLLOWING THE PASSAGE OF THE FRONT...HIGH PRESSURE IS EXPECTED TO
BUILD ACROSS THE REGION THURSDAY AND FRIDAY WHILE BRINGING A RETURN
TO MORE SETTLED CONDITIONS...ALONG WITH CONTINUED LIGHT TO MODEST
WINDS AND MINIMAL WAVES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JJR
NEAR TERM...JJR
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...JJR
MARINE...JJR
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1235 AM CDT TUE SEP 8 2015
.UPDATE...
ISSUED AT 1235 AM CDT TUE SEP 8 2015
HIGH RES MODELS INDICATE THERE WILL BE A CHANCE FOR SOME LIGHT
SHOWERS NORTHWEST INTO NORTH CENTRAL EARLY THIS MORNING AS AN
UPPER LEVEL TROUGH MOVES EAST ACROSS FAR SOUTH CENTRAL CANADA.
ANOTHER SLIGHT CHANCE FOR SHOWERS FAR SOUTHWEST WHERE AN EMBEDDED
WAVE IS DEPICTED TO TRACK NEAR. OVERALL INSIGNIFICANT BUT OPTED TO
ADD/MAINTAIN IN THE FORECAST. TEMPERATURES ONCE AGAIN DROPPING TO
BELOW GUIDANCE...SO TWEAKED BASED ON LATEST OBSERVATIONS.
OPTED TO ALSO THROW IN PATCHY FOG ACROSS MY SOUTHEAST QUARTER
WHERE LAST FEW HRRR RUNS INDICATE SOME DEVELOPMENT. NOT OUT OF THE
QUESTION WITH T/TD SPREADS IN THIS AREA AT OR NEAR ZERO ALREADY.
UPDATE ISSUED AT 918 PM CDT MON SEP 7 2015
ONE STRONG THUNDERSTORM REMAINS OVER FAR SOUTHWEST DICKEY IN THE
APEX OF AN AXIS OF INSTABILITY EXTENDING INTO SOUTH DAKOTA.
LATEST MESO-ANALYSIS INDICATES THE STORM MAY NOW BE MOVING AHEAD
OF THE GREATEST INSTABILITY...ALTHOUGH SHEAR REMAINS ABUNDANT.
HAVE EXTENDED THUNDERSTORM CHANCES THROUGH 04Z ACROSS SOUTHERN
DICKEY COUNTY.
SHOWERS HAVE ALL BUT DISSIPATED ACROSS THE NORTHWEST AND NORTH
CENTRAL. COULD STILL SEE A SPRINKLE OR TWO THIS EVENING BUT NOT
ENOUGH COVERAGE TO KEEP A MENTION OF MEASURABLE PRECIPITATION.
UPDATE ISSUED AT 701 PM CDT MON SEP 7 2015
QUICK UPDATE TO ADD A MENTION OF THUNDER FOR A FEW HOURS THIS
EVENING OVER THE FAR SOUTH CENTRAL FROM AROUND STRASBURG ACROSS
MCINTOSH AND INTO DICKEY COUNTY. AXIS OF INSTABILITY OVER CENTRAL
SOUTH DAKOTA IS EXTENDING INTO THE FAR SOUTH CENTRAL WITH GOOD
BULK SHEAR OVER THE AREA. THIS SHOULD BE A SHORT LIVED EVENT
ENCOMPASSING THIS SMALL AREA.
UPDATE ISSUED AT 632 PM CDT MON SEP 7 2015
AFTERNOON SHOWERS HAVE EXITED EASTERN PORTIONS OF CENTRAL NORTH
DAKOTA. A FEW SHOWERS WERE LOCATED OVER NORTHEAST MONTANA INTO FAR
NORTHWEST NORTH DAKOTA ASSOCIATED WITH A SHORTWAVE ROTATING
AROUND THE BASE OF THE UPPER LEVEL LOW OVER MANITOBA. MOST LIKELY
NOTHING MORE THAN A SPRINKLE OR BRIEF SHOWER EXPECTED HERE BUT DID
KEEP SOME SLIGHT CHANCE POPS OVER THE NORTHWEST EARLY THIS
EVENING. ALSO BUMPED UP SKY COVER A BIT OVER THE NORTHWEST.
OTHERWISE NO SIGNIFICANT UPDATES TO THE GOING FORECAST.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 256 PM CDT MON SEP 7 2015
RAIN SHOWERS ENDING BY EARLY THIS EVENING CENTRAL HIGHLIGHT THE
SHORT TERM FORECAST.
WILL CONTINUE TO RELY ON A TIME LAGGED ENSEMBLE OF THE HRRR FOR
POPS THE REMAINDER OF THE AFTERNOON...NAMELY ITS 16-18 UTC
ITERATIONS...WHICH HAS DONE WELL THROUGHOUT THE DAY. DID MAINTAIN
A SLIGHT CHANCE OF THUNDER WITH A FEW...SPORADIC LIGHTNING
STRIKES OBSERVED. EXPECT PRECIPITATION CHANCES...FOCUSED PRIMARILY
ACROSS NORTH CENTRAL NORTH DAKOTA AND THE UPPER JAMES RIVER VALLEY
THE REST OF THE DAY...TO RAPIDLY DECREASE BY 22-23 UTC AS FORCING
FROM TWO SHORTWAVES SOUTH OF THE UPPER LOW NEAR LAKE WINNIPEG
SHIFTS EAST.
FOR TUESDAY...A QUIET...DRY...ALBEIT SLIGHTLY BELOW NORMAL
TEMPERATURE-WISE DAY IS FORECAST SOUTH OF THE NOW FILLING
AFOREMENTIONED LOW. GIVEN GOOD AGREEMENT...UTILIZED A BLEND OF THE
12 UTC GUIDANCE SUITES FOR ALL FIELDS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 256 PM CDT MON SEP 7 2015
NORTHWEST FLOW ALOFT THROUGH FRIDAY WITH FLOW ROTATING AROUND THE
HUDSON BAY LOW AND RIDGE OVER THE EASTERN PACIFIC AND WEST COAST.
SHORTWAVE ENERGY MOVING THROUGH THIS FLOW APPROACHES NORTHERN NORTH
DAKOTA LATE TUESDAY NIGHT/WEDNESDAY MORNING...WITH AN ATTENDANT WEAK
SURFACE LOW AND COLD FRONT. MORE SHORTWAVE ENERGY IMPULSES MOVE
SOUTHEAST ACROSS THE STATE WEDNESDAY AFTERNOON WITH A COLD FRONT
MOVING SOUTH ACROSS THE STATE. THIS WILL RESULT IN SLIGHT CHANCES OF
SHOWERS...MAINLY NORTHWEST AND CENTRAL...ON WEDNESDAY. SEASONABLE
TEMPERATURES WEDNESDAY WITH HIGHS FROM THE UPPER 60S NORTH TO UPPER
70S SOUTH.
ANOTHER SERIES OF SHORTWAVES MOVES ACROSS THE STATE WEDNESDAY NIGHT
WITH A SECONDARY PUSH OF COLD AIR IN THE FORM OF A BACKDOOR COLD
FRONT MOVING SOUTHWEST ACROSS THE STATE. SLIGHT CHANCES OF SHOWERS
WILL REMAIN IN THE FORECAST NORTHWEST AND CENTRAL WEDNESDAY
NIGHT...WITH MAINLY DRY BUT COOL CONDITIONS EXPECTED THURSDAY. LOOK
FOR HIGHS IN THE 60S TO LOWER 70S.
THE UPPER LEVEL WESTERN RIDGE BUILDS BACK INTO THE REGION FOR THE
WEEKEND...WITH DRY CONDITIONS AND SLIGHTLY ABOVE AVERAGE
TEMPERATURES. HIGHS IN THE 70S TO LOWER 80S.
THE MODELS BRING AN UPPER LEVEL SHORTWAVE MOVING THROUGH THE
FLOW...FLATTENING THE RIDGE...BRINGING A CHANCE OF SHOWERS AND
COOLER WEATHER FOR MONDAY WITH HIGHS MAINLY IN THE 60S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1235 AM CDT TUE SEP 8 2015
VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD WITH MID TO
UPPER LEVEL CLOUDS STREAMING EAST ACROSS THE REGION. AN ISOLATED
SHOWER POSSIBLE NORTHWEST EARLY THIS MORNING BUT TOO SCARCE TO
MENTION IN KISN OR KMOT TAF. PATCHY FOG MAY BE POSSIBLE AT
KBIS/KJMS TONIGHT. HOWEVER...GIVEN HIGH UNCERTAINTY...LEFT THIS
ALSO OUT OF THE TAFS FOR NOW.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...AYD
LONG TERM...JV
AVIATION...NH
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
110 AM EDT TUE SEP 8 2015
.SYNOPSIS...
HIGH PRESSURE ALONG THE MID-ATLANTIC WILL WEAKEN AS IT MOVES TO THE
SOUTHEASTERN STATES THROUGH MID-WEEK. A SLOW MOVING COLD FRONT OVER
THE CENTRAL GREAT LAKES WILL STALL NORTH OF LAKE ERIE ON TUESDAY. A
WAVE OF LOW PRESSURE WILL MOVE NORTHEAST ALONG THE BOUNDARY ON
WEDNESDAY AND PULL THE FRONT SOUTH ACROSS THE AREA.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
WILL CONTINUE TO IGNORE
THE OVERDONE HRRR AND RAP THAT HAVE BEEN TRYING TO DEVELOP SCT
CONVECTION AROUND THE CWA ALL AFTERNOON AND EVENING.
A SLOW MOVING COLD FRONT IS EXPECTED TO STALL TONIGHT JUST NORTH OF
LAKE ERIE. CONVECTION ALONG THE DIFFERENTIAL HEATING BOUNDARY ON THE
LEADING EDGE OF THE FRONT WILL APPROACH AS THE FRONT SINKS SOUTH BUT
IS GENERALLY EXPECTED TO REMAIN NORTH OF OHIO AS IT OUTPACES THE
FRONT/MOISTURE AXIS WITH SOUTHWESTERLY FLOW THROUGH THE COLUMN
ALOFT. CAN NOT ENTIRELY RULE OUT SOMETHING CLIPPING THE TOLEDO AREA
OR SNEAKING OFF THE LAKE TOWARDS ERIE PA SO WILL CONTINUE WITH A LOW
20 POP IN THOSE AREAS.
DEWPOINTS SHOULD INCH UP IN NORTHWEST OHIO AND WITH INCREASING HIGH
CLOUD WILL KEEP MINS SLIGHTLY WARMER NEAR 70 DEGREES...EXTENDING
EAST ALONG THE LAKESHORE. INLAND NE OHIO WILL BOTTOM OUT IN THE
LOWER TO MID 60S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/...
ALTHOUGH SURFACE BOUNDARY AND LARGER SCALE FORCING REMAINS WEST OF
THE AREA ON TUESDAY...ADDED A SLIGHT CHANCE ACROSS NORTHERN COUNTIES
AS LOW LEVEL THETA-E AXIS SINKS SOUTH. EXPECT CONVECTION TO DEVELOP
ACROSS NORTHERN INDIANA AND LOWER MICHIGAN AS SHORTWAVE ENERGY LIFTS
NORTHEAST ACROSS THAT AREA. SOME OF THE UPSTREAM CONVECTION MAY
START TO TRICKLE INTO NORTHWEST OHIO BY EVENING...ESPECIALLY IF
OUTFLOW BOUNDARIES START TO MOVE OUT AHEAD OF THE FRONT SO DID
INCLUDE A CHANCE POP IN NW OHIO AND SLIGHT CHANCE POPS ACROSS THE
NORTHERN COUNTIES. TEMPERATURES WILL BE HOT FOR ONE MORE DAY IN THE
UPPER 80S TO NEAR 90.
A PRETTY GOOD PIECE OF SHORTWAVE ENERGY WILL ROUND THE TROUGH AND
LIFT NORTHEAST ACROSS THE AREA ON WEDNESDAY. THIS OCCURS AS THE
FRONT PUSHES SOUTH AND SHOULD RESULT IN GOOD COVERAGE OF SHOWERS AND
THUNDERSTORMS. KEPT POPS IN THE 60-70 PERCENT RANGE FOR THE DAYTIME
ON WEDNESDAY. SHEAR INCREASES FROM THE WEST LATER IN THE DAY BUT THE
BETTER STORMS MAY BE OUT AHEAD OF THIS AREA WHERE THERE IS MORE
HEATING AND INSTABILITY. NOT INCLUDED IN A SLIGHT RISK AT THIS TIME
BUT COULD ANTICIPATE A FEW STRONG TO SEVERE STORMS IF WE ACHIEVE
SUFFICIENT HEATING. THE CLOUDS AND COVERAGE OF STORMS WILL LIMIT
HIGHS TO THE UPPER 70S TO LOW 80S.
THE FRONT PUSHES SOUTH WEDNESDAY NIGHT AND WE SHOULD DRY OUT ON
THURSDAY. HELD ONTO A LOW CHANCE POP ON THURSDAY IN MOSTLY IN
INTERIOR EASTERN AREAS AS LOW LEVEL DRY AIR PUSHES IN FROM THE
NORTH. TEMPERATURES WILL FINALLY BE BACK CLOSER TO NORMAL VALUES IN
THE LOWER TO MID 70S.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
THE NEXT UPPER LEVEL TROUGH WILL BE DIGGING INTO THE CENTRAL GREAT
LAKES ON FRIDAY. THE EXTENDED MODELS DIFFER IN THE STRENGTH OF THE
STORM SYSTEM MOVING THROUGH THE REGION WHICH WILL HAVE IMPACTS ON
RAIN CHANCES. IN ANY EVENT THERE WILL AT LEAST BE ISOLATED TO
SCATTERED SHOWERS FRIDAY AFTERNOON THROUGH FRIDAY. THE BETTER
CHANCES AT THE MOMENT SEEM TO BE ACROSS NE OHIO AND NW PA.
FRIDAY WILL BE THE WARM DAY OF THE LONG TERM WITH HIGHS INTO THE
MIDDLE 70S AT MOST LOCATIONS. IT WILL THEN BE COOLER SATURDAY INTO
SUNDAY WITH HIGHS GENERALLY WITHIN A COUPLE DEGREES OF 70. A FEW
LOCATIONS COULD SEE LOWS INTO THE 40S SUNDAY MORNING.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
MAINLY HIGH CLOUDS WILL SPREAD EAST INTO THE FORECAST AREA AS THE
DAY PROGRESSES. THEN...THREAT FOR SHOWERS AND THUNDERSTORMS WITH
MVFR VISIBILITIES POSSIBLE AFTER 00Z THIS EVENING IN THE WEST AND
AT ERIE. OTHERWISE...REST OF THE TAF SITES SHOULD REMAIN DRY
THROUGH THE FORECAST PERIOD. EXCEPTION IS CLEVELAND SHOULD SEE
THUNDERSTORM ACTIVITY AFTER 06Z. CEILINGS SHOULD REMAIN
PREDOMINANTLY VFR DURING THE THUNDERSTORMS. WINDS SHOULD BE 10
KNOTS OR LESS FROM THE SOUTH SOUTHWEST.
OUTLOOK...NON VFR LIKELY IN SHRA/TSRA WITH A COLD FRONT WEDNESDAY.
NON VFR MAY LINGER INTO THURSDAY MORNING. NON-VFR POSSIBLE ON
SATURDAY WITH THE NEXT COLD FRONT.
&&
.MARINE...
HIGH PRESSURE WILL CONTINUE TO MOVE SOUTHWARD FROM THE MIDDLE
ATLANTIC STATES. THIS WILL ALLOW A COLD FRONT TO MOVE INTO THE
CENTRAL GREAT LAKES LATE MONDAY INTO TUESDAY. SOUTHWESTERLY WINDS
AHEAD OF THE FRONT WILL INCREASE ON MONDAY INTO TUESDAY. AS THE FRONT
PASSES WEDNESDAY EVENING WEST TO NORTHWEST WINDS MAY TOP OUT IN THE
15 TO 20 KNOT RANGE WHICH WILL GET WAVES CLOSE TO SMALL CRAFT
CRITERIA. IF THIS DOES OCCUR IT WILL BE OVERNIGHT WEDNESDAY NIGHT
INTO THURSDAY MORNING. HIGH PRESSURE WILL THEN BRIEFLY RIDGE ACROSS
LAKE ERIE FROM THE UPPER GREAT LAKES THURSDAY INTO FRIDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KEC
NEAR TERM...ADAMS
SHORT TERM...KEC
LONG TERM...MULLEN
AVIATION...LOMBARDY
MARINE...MULLEN
AREA FORECAST DISCUSSION
NWS TULSA OK
1153 PM CDT MON SEP 7 2015
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
For the 6Z TAFs, VFR conditions will prevail at all sites
throughout the forecast period. Thunderstorm chances will
increase during the afternoon at northern TAF sites as a cold
front approaches from the north. As the cold front moves into the
region Tuesday night, thunderstorm chances will spread to all TAF
sites.
&&
.PREV DISCUSSION... /ISSUED 831 PM CDT MON SEP 7 2015/
UPDATE...
Pops have been removed for the evening hours and the heat headline
has been cancelled. See discussion below.
DISCUSSION...
Temps have cooled with the loss of daytime heating and thus the
heat headline was cancelled. The isolated showers and storms have
also dissipated...and thus pops have been removed for the
evening. Will take a look at the 00z data to determine whether
pops may be needed to the north and west of Tulsa late tonight.
The latest runs of the HRRR do indicate that some high based
activity will slide east along the KS/OK border tonight.
Lacy
PREV DISCUSSION... /ISSUED 610 PM CDT MON SEP 7 2015/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
For the 0Z TAFs, VFR conditions will prevail at all sites
throughout the 24 hour forecast period. Thunderstorm chances will
increase during the afternoon at our northern TAF sites as a cold
front approaches from the north. Frontal passage will be after
this forecast period.
PREV DISCUSSION... /ISSUED 338 PM CDT MON SEP 7 2015/
DISCUSSION...
Late summer heat will continue into Tuesday with the forecast
trended warmer despite the potential for more extensive cloud
cover tomorrow. Convection will develop across southern KS
tomorrow afternoon and spread southeastward by late afternoon and
early evening. Forecast soundings have steep low level lapse rates
amid a plume of 1.75-2 inch precip water with decreasing deep
layer shear w/ southward extent. This would favor downburst
potential and potential aggressive outflow winds w/ the strongest
storms. This potential will also keep northern locations from
otherwise being just as hot tomorrow.
The actual frontal boundary will become the focus for widespread evening
and overnight convection w/ a trend away from severe weather
potential and more toward locally heavy rain. The boundary will
focus precip toward southern areas Wednesday...with the post
frontal air being cooler but not much drier initially.
The stronger push of drier air arrives late Thurs-Friday
associated with another passing wave. A brief shot of precip may
accompany this wave otherwise dry and pleasant conditions look
likely for next weekend. The GFS is an outlier at this range w/
regards to precip potential and favored the GEM/ECMWF solutions.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...06
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
602 AM EDT TUE SEP 8 2015
.SYNOPSIS...
A RIDGE OF HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH EARLY
WEDNESDAY. A SLOW-MOVING COLD FRONT WILL THEN PRESS SOUTHEAST
ACROSS THE AREA LATE WEDNESDAY AND THURSDAY. A DEEPENING UPPER
LEVEL TROUGH AND ASSOCIATED COLD FRONT WILL LIKELY PUSH THROUGH
PENNSYLVANIA NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
11-3.9U IMAGERY SHOWING SOME PATCHY DENSE FOG IN THE DEEP VALLEYS
NORTH OF I-80 EARLY THIS MORNING. THE FOG SHOULD BURN OFF BY ARND
13Z PER LATEST HRRR/LAMP. CENTRAL PA WILL REMAIN BENEATH UPPER RIDGE
AXIS TODAY...WITH LARGE SCALE SUBSIDENCE AND RELATIVELY LOW PWATS
LIKELY ENSURING A MSUNNY...HOT AND DRY DAY. CAN/T COMPLETELY RULE
OUT AN ISOLD LATE DAY SHOWER OVR THE ELEVATED HEAT SOURCE OF THE
LAUREL HIGHLANDS AS LATEST HRRR SUGGESTS. HOWEVER...BELIEVE AREAL
COVERAGE OF ANY SHOWERS WOULD BE TOO LOW TO MENTION IN GRIDS
ATTM.
TEMPS SHOULD BE AT LEAST AS WARM AS YESTERDAY OR PERHAPS EVEN A
DEG OR TWO HIGHER BASED ON GEFS MEAN 925/850 TEMPS. MAXES WILL
RANGE FROM THE U80S ACROSS THE ALLEGHENY PLATEAU...TO THE L90S
ACROSS THE SUSQ VALLEY. RECORD HIGH OF 92F AT KIPT COULD BE IN
JEOPARDY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
AFTER ANOTHER VERY WARM AND TRANQUIL NIGHT...APPROACHING SHORTWAVE
AND ASSOC COLD FRONT WILL BRING A CHANCE OF SHRA/TSRA WEDNESDAY.
HIGHEST /LIKELY/ POPS ARE PAINTED ACROSS THE NW MTNS CLOSEST TO
APPROACHING COLD FRONT. ALL SHORT RANGE MDLS INDICATE THERE WILL
BE A MINIMUM IN SHOWER ACTIVITY ACROSS THE CENTRAL MTNS IN
CONJUNCTION WITH LINGERING RIBBON OF LOWER PWATS.
PARTLY CLOUDY SKIES AND SCT PM CONVECTION MAY HOLD TEMPS DOWN A
BIT FROM RECENT DAYS. HOWEVER...AIR MASS REMAINS VERY WARM WITH
MDL 8H TEMPS AOA 18C. THEREFORE...EXPECT HIGHS WELL INTO THE
80S...WITH 90F STILL POSSIBLE ACROSS THE SUSQ VALLEY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
MED RANGE MDLS ALL INDICATING INITIAL SHORTWAVE SHEARS OUT AND
LIFTS NORTH OF PA WED NIGHT. TRAILING...SLOW-MOVING COLD FRONT
SHOULD PUSH THRU CENTRAL PA WED NITE/THURSDAY. EXPECT SOME
BENEFICIAL RAINFALL OVR MOST OF THE AREA FROM THIS FEATURE AS
FRONT INTERACTS WITH HIGH MOISTURE/PWAT ANOMALIES. BLEND OF LATEST
ENSEMBLE OUTPUT SUPPORTS WIDESPREAD 0.25 TO 0.50 INCHES...WITH
LOCAL AMTS IN EXCESS OF AN INCH.
A RETURN TO FAIR WX/SEASONAL TEMPS APPEARS LIKELY FRIDAY IN WAKE
OF FRONT. HOWEVER...DIGGING TROF AND ASSOC SECONDARY COLD FRONT
APPEARS LIKELY TO SWING THRU CENTRAL PA OVER THE WEEKEND...BRINING
ANOTHER ROUND OF SHOWERY CONDS. ECENS AND OPER CANADIAN FORMING A
CUT OFF LOW OVR THE OHIO VALLEY...SIGNALING THE UNSETTLED WX COULD
LAST THRU MOST OF THE WEEKEND.
TEMPS MAY BRIEFLY FALL BLW NORMAL ARND SUN-MON...AS UPPER LOW
LIFTS THRU. HOWEVER...LATEST ECENS/NAEFS SUPPORT A RETURN TO ABOVE
NORMAL TEMPS NEXT WEEK...AS TROUGH QUICKLY LIFTS OUT AND UPPER RIDGE
BUILDS ALONG THE EAST COAST.
&&
.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
UNDER A MAINLY CLEAR SKY...PATCHY FOG IS POSSIBLE OVERNIGHT. AS
WAS THE CASE SUNDAY NIGHT...KBFD IS ONCE AGAIN THE TAF SITE MOST
LIKELY TO BE SIGNIFICANTLY AFFECTED.
ANY FOG WILL BURN OFF TUES AM...LEAVING ANOTHER DAY OF
PREDOMINANTLY VFR CONDS. A STRAY LATE-DAY SHRA/TSRA IS AGAIN
POSSIBLE ACROSS THE NW MTNS...BUT THAT IS ABOUT IT. WINDS WILL BE
NEARLY CALM TO START THE DAY...THEN BECOME LIGHT OUT OF THE SW BY
AFTN.
THINGS WILL TURN A BIT MORE UNSETTLED FOR THE SECOND HALF OF THE
WEEK...AS A COLD FRONT APPROACHES FROM THE GREAT LAKES WEDNESDAY
AND CROSSES PA ON THURSDAY.
OUTLOOK...
WED...SCATTERED LATE-DAY SHRA/TSRA POSSIBLE.
THU...MORE NUMEROUS SHRA/TSRA EXPECTED.
FRI...PATCHY MORNING FOG POSSIBLE...OTHERWISE GENERALLY VFR.
SAT...WIDELY SCATTERED LATE-DAY SHRA/TSRA POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD/CERU
AVIATION...GARTNER/EVANEGO
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
333 AM CDT TUE SEP 8 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 333 AM CDT TUE SEP 8 2015
MAIN FCST CONCERNS THIS PERIOD...SHRA/TSRA CHANCES THIS MORNING...
TEMPERATURES.
DATA ANALYSIS AT 06Z HAD THE OLD FRONTAL BOUNDARY NEAR THE WI/IL
BORDER TO NEAR KDSM/KOMA. A WEAK LOW WAS LOCATED ON THE FRONT NEAR
KOMA. PER WV IMAGERY...A SHORTWAVE WAS MOVING EAST-NORTHEAST ACROSS
OVER NEB. INCREASING LOWER LEVEL THERMO-DYNAMIC FORCING AND MOISTURE
TRANSPORT AHEAD OF THE SFC-700MB TROUGH AND LIFT AHEAD OF THE
SHORTWAVE PRODUCING INCREASING SHRA/TSRA ACROSS SOUTHWEST MN/
NORTHWEST IA. WSR-88D RAINFALL ESTIMATES OF 1-2 INCHES/HR FROM SOME
OF THE TSRA IN SOUTHWEST MN. ELSEWHERE...IT REMAINED ANOTHER WARM
AND HUMID EARLY SEPT NIGHT ACROSS MUCH OF THE UPPER MIDWEST UNDER
INCREASING CLOUD COVER.
08.00Z MODEL RUNS LOOK TO HAVE INITIALIZED WELL. SOLUTIONS QUITE
SIMILAR...AT LEAST AT 500MB...AS ONE SHORTWAVE PASSES EARLY THIS
MORNING THEN THE MAIN MID LEVEL TROUGH AXIS PASSES TONIGHT. TREND IS
TOWARD A TIGHTER CONSENSUS OF THE EARLIER RUNS THRU TONIGHT. STILL
SOME MESO-SCALE DETAIL DIFFERENCES IMPACTING PRECIP PLACEMENT/TIMING
THIS MORNING BUT THIS NOT UNEXPECTED. EVEN WITH THESE DIFFERENCES...
SHORT-TERM FCST CONFIDENCE IS GOOD THIS CYCLE.
FOR THE SHORT TERM...REGIONAL RADAR COMPOSITE SHOWING THE MORE
NORTHERN OF MODEL SOLUTIONS WITH SHRA/TSRA/QPF LOOKING BETTER EARLY
THIS MORNING. RADAR PRECIP ESTIMATES ALSO SHOWING MODEL SOLUTIONS
WITH HEAVIER QPF ALSO LOOKING BETTER. GIVEN PW VALUES OF UP TO 1.75
INCHES /2.5 STANDARD DEVIATIONS ABOVE NORMAL/ IN THE INFLOW
AIRMASS...TREND FOR STORMS TO BE EFFICIENT/HEAVY RAIN PRODUCERS
SHOULD CONTINUE AS THE FORCING/CONVECTION MOVE EAST ACROSS THE FCST
AREA THIS MORNING. RAISED QPF IN THE FCST GRIDS...BUT NOT ALL AREAS
WILL SEE 1 TO 2 INCHES OF RAIN. HOWEVER...IF THIS RAIN FALLS IN
URBAN AREAS...AREAS HIT BY HEAVY RAINS IN RECENT DAYS...OR TSRA
TRAIN/REPEAT OVER THE SAME AREA...MORE FLOODING ISSUES ARE CERTAINLY
POSSIBLE. AFTER COLLABORATION WITH NEIGHBORS...HAVE ISSUED A FLASH
FLOOD WATCH FOR MUCH OF THE FCST AREA FROM 09Z-15Z /NORTHWEST THIRD/
OR 09Z-18Z /CENTRAL AND SOUTH PARTS/ TODAY. WITH PASSAGE OF THE
SHORTWAVE AND SFC-500MB TROUGH AXIS...FORCING/LIFT AND DEEPER
MOISTURE QUICKLY MOVE EAST OF THE AREA BY LATE THIS MORNING INTO
EARLY THIS AFTERNOON. CARRIED HIGHEST SHRA/TSRA CHANCES IN THE 12-
15Z PERIOD THIS MORNING...TRENDING DOWN AND EASTWARD RATHER QUICKLY
THRU THE LATE MORNING/EARLY AFTERNOON HOURS. SFC-700MB WINDS REMAIN
LIGHT TODAY...WITH LOWER LEVEL MOISTURE/CLOUDS BEHIND THE LOW/TROUGH
AXIS LIKELY SLOW TO CLEAR OUT. HAVE RAISED CLOUD COVER IN GRIDS THRU
MUCH OF TODAY. STRONGER OF THE LOWER LEVEL DRYING/COOLING PUSHES IN
TONIGHT WITH PASSAGE OF THE MAIN MID LEVEL TROUGH AXIS. MODELS
SHOWING PW VALUES DROP TO AROUND 1/2 INCH OVER THE AREA BY 12Z WED.
WITH LOWER LEVEL COLD ADVECTION AND ANTI-CYCLONIC FLOW...SKIES
EXPECTED TO BECOME CLEAR/MOSTLY CLEAR BY LATE EVENING. LOWER LEVEL
COLD ADVECTION...LIGHT BOUNDARY LAYER WINDS AND THE MOSTLY CLEAR
SKIES...LOWS TONIGHT TRENDING TO BE MUCH CLOSER TO NORMAL THAN THOSE
OF THE PAST WEEK. STAYED WITH A BLEND OF THE GUIDANCE HIGHS/LOWS FOR
TODAY/TONIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 333 AM CDT TUE SEP 8 2015
FOR WEDNESDAY THRU THURSDAY NIGHT...
MAIN FCST CONCERNS THIS PERIOD...SHRA/TSRA CHANCES LATE WED NIGHT
INTO THU NIGHT...TEMPERATURES.
08.00Z MODEL RUNS IN GOOD AND IMPROVING AGREEMENT THIS PERIOD AS
HGTS FALL/MID LEVEL TROUGHING DEEPENS OVER THE NORTH CENTRAL CONUS.
GENERALLY TREND IS DEEPER/STRONGER WITH THE TROUGH AND SHORTWAVE
ENERGY IN IT OVER THE REGION BY THU/THU NIGHT. GIVEN THE TIGHTER
MODEL CONSENSUS...FCST CONFIDENCE THIS PERIOD IS GOOD THIS CYCLE.
QUIET...DRY...MOSTLY SUNNY...SEASONABLE DAY ON WED AS CANADIAN HIGH
PRESSURE AND A DRY LOWER LEVEL AIRMASS SLIDE ACROSS THE UPPER
MIDWEST. THIS DOES NOT LAST LONG WITH THE TROUGH ALOFT DEEPENING AND
APPROACH OF THE LEAD SHORTWAVE ENERGY. NEXT SFC TROUGH/FRONT IS
ALREADY INTO NORTHERN WI TO SOUTHWEST MN BY 12Z THU. CONSISTENT
SIGNAL FOR LOWER LEVEL MOISTURE TO QUICKLY RETURN NORTHWARD AHEAD OF
THE SFC-700MB TROUGH...ALONG WITH AN INCREASE OF LOWER LEVEL
CONVERGENCE/ISENTROPIC LIFT. SOME WEAK MUCAPE EVEN INDICATED AHEAD
OF THE TROUGH BY 12Z THU. SMALL SHRA/ISOLATED TSRA CHANCE OVER THE
NORTHWEST HALF OF THE FCST AREA LATER WED NIGHT REASONABLE FOR NOW.
MOISTURE/CAPE AHEAD OF THE LOWER LEVEL TROUGH CONTINUE TO INCREASE
ON THU. SOME TIMING DIFFERENCES WITH PROGRESSIVENESS OF THE SFC-
700MB TROUGH/FRONT BY 00Z FRI. HOWEVER TIGHTENING CONSENSUS FOR ENOUGH
LIFT/MOISTURE FOR SOME SHRA/TSRA TO ACCOMPANY IT AS IT MOVES ACROSS
THE FCST AREA THU/THU NIGHT. STAYED WITH THE CONSENSUS SHRA/TSRA
CHANCES FOR THU/THU NIGHT FOR NOW...PENDING BETTER TIMING AGREEMENT
AMONG THE MODELS. STRONGER SHOT OF LOW LEVEL COLD ADVECTION FOLLOWS
IN THE WAKE OF THE TROUGH/FRONT FOR THU NIGHT...WITH THU NIGHT LOWS
TRENDING BELOW NORMAL. USED A BLEND OF THE GUIDANCE HIGHS/LOWS FOR
WED THRU THU NIGHT.
FOR FRIDAY THRU MONDAY...DAYS 4 TO 7...
MAIN FCST CONCERNS THIS PERIOD...COOLER TEMPERATURES...SMALL SHRA
CHANCES BY SUN NIGHT/MON.
MEDIUM RANGE MODEL RUNS OF 08.00Z SHOW IMPROVING AGREEMENT FOR
TROUGHING TO DEEPEN OVER THE GREAT LAKES FRI THRU SAT...WITH DEEP
NORTHERLY FLOW OVER THE REGION BY 00Z SUN. REASONABLE CONSENSUS FOR
THE TROUGHING TO DIG INTO THE EASTERN CONUS SAT NIGHT/SUN...WITH
SHORTWAVE RIDGING/RISING HGTS BUILDING INTO THE UPPER MIDWEST BEHIND
IT. BY SUN NIGHT/MON SOME CONSISTENCY FOR HGTS TO FALL AGAIN AS A
STRONGER SHORTWAVE TRACKS EAST ALONG THE US/CAN BORDER. WITH THE
BETTER MODEL CONSENSUS...THE LONG TERM FCST CONFIDENCE IS ABOVE
AVERAGE THIS CYCLE.
THIS PERIOD STARTS OUT WITH CAN HIGH PRESSURE BUILDING INTO THE
REGION. DEEP NORTHWEST TO NORTH FLOW CONTINUES TO SPREAD LOW LEVEL
COLD ADVECTION SPREADING ACROSS THE AREA WITH 850MB TEMPS BY 00Z SAT
1 TO 2 STANDARD DEVIATIONS BELOW NORMAL. FRI THRU SAT CONTINUES TO
SHAPE UP AS A DRY...COOL PERIOD WITH TEMPS SOME 5F TO 10F BELOW
NORMAL. SFC-850MB HIGH WOULD MOVE SOUTH OF THE AREA BY SUNDAY...WITH
SOME LOW LEVEL WARM ADVECTION RETURNING. TROUGHING/SHORTWAVE MOVING
ACROSS SOUTHERN CAN SUN NIGHT/MON WOULD DRAG A FRONTAL BOUNDARY INTO
THE REGION...WITH AN INCREASE OF MOISTURE/CONVERGENCE/LIFT AND SOME
MUCAPE AHEAD OF IT. PLENTY OF TIMING DIFFERENCES BY MON...BUT A
SMALL SHRA/TSRA CHANCE ACROSS MAINLY THE NORTH END OF THE FCST AREA
BY LATER SUN NIGHT/MON REASONABLE AT THIS POINT. MODEL/ENSEMBLE
CONSENSUS OF HIGHS/LOWS FOR FRI THRU MON SEEMS TO HAVE THEM WELL
TREND AT THIS TIME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1143 PM CDT MON SEP 7 2015
WATCHING THE CONVECTION SLOWLY FILL IN ACROSS NORTHWEST IOWA AND
SOUTHWEST MINNESOTA AHEAD OF THE SHORT WAVE TROUGH COMING OUT OF
NEBRASKA. SEVERAL OF THE HI-RES MESO MODELS NOW SUGGEST THIS AREA
WILL CONTINUE TO EXPAND AND SWING THOUGH THE INTERSTATE 90 CORRIDOR
LATE TONIGHT INTO EARLY TUESDAY MORNING. HAVE THUS TRENDED THE
FORECAST TOWARD THESE SOLUTIONS OF BRINGING SOME LEADING SHOWERS
WITH A VCSH BEFORE THE MAIN BAND OF SHOWERS AND STORMS COMES IN. THE
08.03Z RAP FORECAST SOUNDINGS SUGGEST THE POTENTIAL FOR IFR
CONDITIONS AS THIS COMPLEX OF STORMS MOVES THROUGH AND IF IT EVOLVES
AS THE MESO MODELS SUGGEST...THIS SEEMS ENTIRELY REALISTIC. THE
COMPLEX SHOULD MOVE OUT FAIRLY QUICKLY TUESDAY MORNING BUT EXPECTING
THE IFR CEILINGS TO REMAIN UNTIL LATE AFTERNOON UNTIL SOME DRIER AIR
STARTS TO WORK IN FROM THE NORTHWEST TO ALLOW THE CONDITIONS TO GO
UP TO VFR.
&&
.HYDROLOGY...
ISSUED AT 333 AM CDT TUE SEP 8 2015
HAVE ISSUED A FLASH FLOOD WATCH FOR MUCH OF THE FCST AREA FROM 09Z
THIS MORNING TO 15Z /NORTHWEST 1/3/ TO 18Z /ELSEWHERE/. SHRA/TSRA
JUST WEST OF THE FCST AREA HAVE A HISTORY OF BEING EFFICIENT RAIN
MAKERS WITH UP TO 1 TO 2 INCHES/HR. ANTECEDENT CONDITIONS ACROSS
PORTIONS OF THE FCST AREA NOT THE MOST FAVORABLE FOR FLASH
FLOODING BUT WITH SOME POTENTIAL FOR STORMS TO TRAIN/REPEAT THIS
MORNING...CANNOT RULE OUT POSSIBILITY OF LOCAL 3+ INCH RAIN
AMOUNTS SOMEWHERE WITHIN THE FCST AREA. IF 1 TO 2 INCHES/HR WOULD
OCCUR OVER AN URBAN AREA...RUNOFF/FLOODED STREETS WOULD DEVELOP
RATHER QUICKLY AND BECOME A PROBLEM...POTENTIALLY DURING THE
MORNING COMMUTE. SEE SHORT-TERM DISCUSSION FOR A BIT MORE ON THE
HEAVY RAIN/FLASH FLOOD THREAT THIS MORNING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...FLASH FLOOD WATCH UNTIL 1 PM CDT THIS AFTERNOON FOR WIZ029-033-
034-041-042-053>055-061.
FLASH FLOOD WATCH UNTIL 10 AM CDT THIS MORNING FOR WIZ032.
MN...FLASH FLOOD WATCH UNTIL 1 PM CDT THIS AFTERNOON FOR MNZ088-095-
096.
FLASH FLOOD WATCH UNTIL 10 AM CDT THIS MORNING FOR MNZ079-086-
087-094.
IA...FLASH FLOOD WATCH UNTIL 1 PM CDT THIS AFTERNOON FOR IAZ009>011-
018-019-029-030.
FLASH FLOOD WATCH UNTIL 10 AM CDT THIS MORNING FOR IAZ008.
&&
$$
SHORT TERM...RRS
LONG TERM....RRS
AVIATION.....04
HYDROLOGY....RRS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1143 PM CDT MON SEP 7 2015
.SHORT TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 305 PM CDT MON SEP 7 2015
A WARM FRONT WAS HUNG UP OVER SOUTHERN IA...STRETCHING INTO SOUTHERN
WI. THE LOW LEVEL JET WILL INCREASE THIS EVENING...PUSHING INTO AND
ACROSS THE BOUNDARY. A LOFT...THE RIGHT ENTRANCE REGION OF A 300 MB
JET STREAK WILL ENHANCE THE AVAILABLE LIFT. HIGH PWS OF 2 INCHES...A
+2 ANOMALY VIA NAEFS...WITH WARM CLOUD DEPTHS OF 4 KFT...AROUND AND
NORTH OF THE FRONT. A RIPPLE IN THE UPPER LEVEL FLOW IS ALSO PROGGED
TO SLIDE FROM THE SOUTHERN PLAINS TO ACROSS THIS FRONT OVERNIGHT.
ALL THIS SHOULD RESULT IN A BLOSSOMING AREA OF SHOWERS AND
THUNDERSTORMS...CAPABLE OF HEAVY RAIN. MESO MODELS TRENDS FAVOR
KEEPING THE BULK OF THE PCPN THREAT ALONG AND SOUTH OF I-90...WITH
THE HEAVY RAIN MOSTLY CONFINED TO IOWA.
MODEL TRENDS HAVE BEEN SLOWING THIS SYSTEM DOWN A BIT OVER THE PAST
FEW DAYS...AND EXPECT PCPN TO LINGER ACROSS THE EAST TUE MORNING.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 305 PM CDT MON SEP 7 2015
DOWNTURN IN THE TEMPERATURES AS LARGE SCALE PATTERN SHIFT FROM
RIDGING TO TROUGH/NORTHWEST FLOW CONTINUES. 850 MB TEMPS ARE
EXPECTED TO DROP FROM 18 C AT 00Z TUE TO 5 C BY 00Z SAT. NAEFS 850
MB TEMP ANOMALIES HOVER NEAR -1 THU THROUGH THE WEEKEND. A DAY OR
TWO WITH HIGHS ONLY IN THE 60S AND LOWS IN THE 40S ARE EXPECTED -
WITH FRI/SAT MORNING LOOKING LIKE THE COOLEST PERIOD.
VARIOUS RIPPLES WILL MOVE ALONG THE NORTHWEST FLOW...WITH PREVIOUS
MODEL RUNS TAKING THEM MOSTLY NORTH/SOUTH OF THE LOCAL AREA...OR
WEAKENING THEM AS THEY MOVED IN. LAST RUN OR TWO THEY HAVE CHANGED
THEIR TUNE. THE GFS/GEM/ECMWF ALL SLIDE AN UPPER LEVEL SHORTWAVE
ACROSS THE UPPER MISSISSIPPI RIVER VALLEY THU/FRI. THAT AND A
RELATED SFC BOUNDARY COULD SPARK SHOWERS/STORMS AS IT MOVES THROUGH.
NOT MUCH INSTABILITY...SO IF PCPN DEVELOPS...MORE ON THE SHOWER THAN
THUNDERSTORM SIDE. SHOWERS COULD LINGER/REDEVELOP ON FRIDAY IN WRAP
AROUND REGION OF THE SFC LOW/FAVORABLE LOW LEVEL LAPSES...MORE SO
ACROSS NORTHERN WI.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1143 PM CDT MON SEP 7 2015
WATCHING THE CONVECTION SLOWLY FILL IN ACROSS NORTHWEST IOWA AND
SOUTHWEST MINNESOTA AHEAD OF THE SHORT WAVE TROUGH COMING OUT OF
NEBRASKA. SEVERAL OF THE HI-RES MESO MODELS NOW SUGGEST THIS AREA
WILL CONTINUE TO EXPAND AND SWING THOUGH THE INTERSTATE 90
CORRIDOR LATE TONIGHT INTO EARLY TUESDAY MORNING. HAVE THUS
TRENDED THE FORECAST TOWARD THESE SOLUTIONS OF BRINGING SOME
LEADING SHOWERS WITH A VCSH BEFORE THE MAIN BAND OF SHOWERS AND
STORMS COMES IN. THE 08.03Z RAP FORECAST SOUNDINGS SUGGEST THE
POTENTIAL FOR IFR CONDITIONS AS THIS COMPLEX OF STORMS MOVES
THROUGH AND IF IT EVOLVES AS THE MESO MODELS SUGGEST...THIS SEEMS
ENTIRELY REALISTIC. THE COMPLEX SHOULD MOVE OUT FAIRLY QUICKLY
TUESDAY MORNING BUT EXPECTING THE IFR CEILINGS TO REMAIN UNTIL
LATE AFTERNOON UNTIL SOME DRIER AIR STARTS TO WORK IN FROM THE
NORTHWEST TO ALLOW THE CONDITIONS TO GO UP TO VFR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...04
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
850 AM MST TUE SEP 8 2015
.SYNOPSIS...
ISOLATED SHOWERS AND THUNDERSTORMS CAN BE EXPECTED AGAIN
TODAY...FAVORING SOUTHWEST ARIZONA. CLOUDS AND HUMIDITY WILL INCREASE
TUESDAY NIGHT AND WEDNESDAY ALONG WITH A MODEST INCREASE IN RAIN
POTENTIAL LINGERING THROUGH THURSDAY. TEMPERATURES WILL BE LOWER AS
WELL. BY THE END OF THE WEEK TEMPERATURES WILL BE INCREASING AS DRIER
AIR MOVES INTO THE REGION. STORM CHANCES LIMITED TO THE HIGHER
TERRAIN FRIDAY THROUGH MONDAY.
&&
.DISCUSSION... A RATHER WARM...AND MUGGY MORNING (FOR EARLY SEPT)
ACROSS OUR CWA TODAY AS SOUTHWESTERLY FLOW ALOFT PULLS CONSIDERABLE
MID-LEVEL MOISTURE INLAND FROM THE TROPICAL EASTERN PACIFIC. THE
COMBINATION OF THIS MID-LEVEL MOISTURE ALONG WITH A WEAK SHORTWAVE
THAT IS MOVING WESTWARD ACROSS NORTHERN AZ IS TRIGGERING ISOLATED-
SCATTERED SHOWER/THUNDERSTORM ACTIVITY ACROSS SOUTHWEST MARICOPA
COUNTY...WITH ANOTHER AREA OF CONVECTION ACROSS SE PINAL
COUNTY...WHICH IS UNDERNEATH THE PLUME OF DEEPEST MOISTURE WHICH CAN
BE SEEN ON THE LATEST IR SATELLITE IMAGERY. GIVEN THESE LATEST
TRENDS...AND THE CURRENT HRRR HIGH-RES MODEL FORECAST...HAVE DECIDED
TO RAISE POPS A BIT ACROSS SOUTHERN MARICOPA AND NE PINAL COUNTIES
THROUGH THE REST OF THE MORNING HOURS. IT STILL LOOKS LIKE WE WILL
HAVE A BIT OF A BREAK IN THE SHOWER ACTIVITY EARLY THIS AFTERNOON
BEFORE MORE SHOWERS/TSTORMS DEVELOP...MAINLY OVER SW AZ/SE CA LATER
THIS AFTERNOON AND THIS EVENING. AS FAR AS TEMPERATURE/DEWPOINT TRENDS
ARE CONCERNED...OUR HOURLY GRIDS SEEM TO BE HOLDING UP WELL...AND NO
FURTHER UPDATES ARE PLANNED.
&&
.PREVIOUS DISCUSSION... TODAY THROUGH THURSDAY...STRONG
SOUTHWESTERLY FLOW ALOFT CONTINUES OVER THE FORECAST AREA AS WE ARE
SITUATED BETWEEN A HIGH CENTERED OVER FAR NORTHERN MEXICO AND A
TROUGH OFF THE BAJA COAST. THE OTHER SIGNIFICANT FLOW FEATURE OF
INTEREST IS HURRICANE LINDA WHICH WAS CENTERED ABOUT 300 MILES
SOUTHWEST OF THE SOUTHERN TIP OF BAJA EARLY THIS MORNING. CLOSER TO
HOME A BAND OF CLOUDS WAS COVERING MUCH OF THE SOUTHEAST HALF OF
ARIZONA WITH SOME EMBEDDED VERY LIGHT SHOWERS IN A NARROW CORRIDOR
OVER PORTIONS OF MARICOPA...PINAL...AND GILA COUNTIES. THE
CLOUDINESS IS LIKELY BEING AIDED BY THE RIGHT ENTRANCE REGION OF THE
JET INTERACTING WITH RESIDENT MOISTURE ALONG WITH A LITTLE BIT OF
HIGH LEVEL MOISTURE FROM LINDA. MODELS ARE IN GOOD AGREEMENT FOR
TODAY IN SHOWING A WESTWARD SHIFT OF THE HIGH AND A NORTHWARD
DISPLACEMENT OF THE JET. THEY ALSO DO NOT SHOW MUCH OF ANY INCREASE
IN LOWER LEVEL MOISTURE. THUS THEY GENERALLY SHOW A DOWNTREND IN
CAPE FOR TODAY COMPARED TO MONDAY. ONE EXCEPTION IS SOUTHEAST
CALIFORNIA WHERE CAPE EXPANDS FURTHER INTO THE LOWER DESERTS THERE.
THIS ADDS UP TO SLIGHT CHANCES OF SHOWERS AND THUNDERSTORMS ACROSS
THE LOWER ELEVATIONS OF OUR FORECAST AREA...MARGINALLY BETTER OVER
THE HIGHER TERRAIN. TUESDAY NIGHT THROUGH THURSDAY THE FORECAST IS
QUITE CHALLENGING. IN GENERAL...THE MODELS SHOW A GULF SURGE LEADING
TO A SIGNIFICANT INCREASE IN LOWER LEVEL MOISTURE. THEY ALSO SHOW A
SIGNIFICANT INCREASE IN MID AND HIGH LEVEL CLOUDINESS...EMANATING
FROM LINDA. HOWEVER THERE ARE SOME NOTABLE DIFFERENCES IN THE TIMING
AND MAGNITUDE OF THE MOISTURE INCREASE AS WELL AS TIMING AND TRACK
OF ONE OR MORE PERTURBATIONS MOVING NORTHWARD ACROSS THE MEXICO
BORDER. THE NAM IS FASTER WITH THE MOISTURE INCREASE THAN THE GFS
AND ECMWF. IT IS ALSO FASTER WITH THE ARRIVAL OF A SHORT WAVE FROM
BAJA AND TRACKS IT FURTHER EAST FOR MORE IMPACT ON EASTERN PORTIONS
OF OUR AREA. DESPITE ALL OF THAT THE NAM MODEL RUN QPF IS
MODEST...BETTER OVER SOUTHEAST ARIZONA. IN FACT ALL OF THE MODELS
SHOW MODEST QPF INCLUDING THE GFS WHICH TENDS TO BE
OVERDONE...THOUGH IT HAS A COUPLE OF LOCALIZED HIGH TERRAIN
BULLSEYES. THE MAIN REASONS FOR THE UNDERWHELMING MODEL PRECIP
FORECAST IS LACK OF CAPE DUE TO POOR LAPSE RATES AS WELL AS LACK OF
DYNAMICAL FORCING. THUS OUR POPS REMAIN MODEST. THERE COULD BE
SHOWERS AT ANY TIME AND IF ANY OF THEM MANAGE TO HAVE SOME STRENGTH
THEY WILL BE ABLE TO PRODUCE A LOT OF PRECIP IN A VERY LOCALIZED
AREA. AS FOR TEMPERATURES...ANTICIPATE SLIGHTLY WARMER CONDITIONS
TODAY. COOLER CONDITIONS WEDNESDAY WITH MORE CLOUDINESS AND
HUMIDITY...MOST NOTICEABLY OVER SOUTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA...AND SLIGHTLY WARMER THURSDAY AS CLOUDS START TO TREND
DOWN. MEANWHILE...LINDA WILL REMAIN OFFSHORE AND WEAKEN AS IT MOVES
NORTHWESTWARD.
FRIDAY THROUGH MONDAY...
THE FLOW BECOMES MORE AMPLIFIED LATE IN THE WEEK. WITH A RIDGE AXIS
OVER THE INTERIOR WEST. WITH A NORTHERLY COMPONENT TO THE FLOW...A
DRYING TREND IS EXPECTED. ECMWF IS SLOWER WITH THE DRYING THAN THE
GFS BUT IT TENDS TO BE OVERLY GENEROUS WITH MOISTURE. ONLY SLIGHT
CHANCE POPS ARE LEFT OVER THE HIGHER TERRAIN OF SOUTH-CENTRAL ARIZONA
FRIDAY AND SATURDAY. EARLY NEXT WEEK...WEST COAST TROUGHING
REDEVELOPS AND THE RIDGE SHIFTS EASTWARD A BIT SUCH LEADING TO A
SOUTHERLY COMPONENT TO THE FLOW. INTRODUCED SOME SLIGHT CHANCE POPS
SUNDAY AND MONDAY OVER FAVORED HIGHER TERRAIN AREAS AS EVEN THE GFS
SHOWS MORE MOISTURE AVAILABLE.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
BKN-OVC MID/HIGH LEVEL CIGS WILL PREVAIL OVER TERMINAL SITES MUCH OF
THE DAY...WITH VIRGA COMMON THIS MORNING. A STRAY SHOWER/SPRINKLE
MAY BE POSSIBLE THIS MORNING...THOUGH IMPACTS WOULD BE LITTLE TO
NONE. CHANCES FOR ANY STORMS DIRECTLY IMPACTING AN AIRFIELD THIS
AFTERNOON OR EVENING ARE TOO REMOTE TO INCLUDE...AND CONFIDENCE IS
MODERATE THAT TSRA WILL REMAIN WELL REMOVED FROM AERODROMES THROUGH
THE 03Z-04Z EVENING PUSH.
SFC WINDS MAY STAY LIGHT AND VARIABLE THIS MORNING...THOUGH SHOULD
EVENTUALLY FAVOR AN EASTERLY COMPONENT BEFORE SWITCHING TO WESTERLY
EARLY AFTERNOON. CONFIDENCE DECLINES SUBSTANTIALLY LATE THIS EVENING
AND OVERNIGHT...AS A SURGE OF VERY MOIST AIR LIKELY MOVES INTO CNTRL
ARIZONA. VERY LOW CONFIDENCE PRECLUDES A MORE DEFINITE MENTION IN
THIS TAF PACKAGE...HOWEVER SHRA AND CIGS AOB 6K FT COULD BE POSSIBLE
AROUND OR JUST PRIOR TO 12Z WEDNESDAY.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
MOSTLY CLEAR SKIES IN THE MORNING WILL GIVE WAY TO SCT-BKN
CONDITIONS IN THE AFTERNOON. TSRA MAY MORE DIRECTLY IMPACT SERN
CALIFORNIA TERMINALS TUESDAY AFTERNOON VERSUS PREVIOUS DAYS WITH
SOMEWHAT BETTER CONFIDENCE AT KBLH. AFTERNOON STORMS OVER THE
BAJA SPINE AGAIN COULD SURVIVE INTO THE LOWER DESERTS OF IMPERIAL
COUNTY...BUT CONFIDENCE ON ACTIVITY REACHING KIPL IS NOT HIGH ENOUGH
TO EVEN INCLUDE A VICINITY MENTION.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
SLIGHT SHOWER AND THUNDERSTORM CHANCES THURSDAY WILL TAPER OFF TO
NEARLY NEGLIGIBLE CHANCES BY THE WEEKEND. INCREASED HUMIDITY
LEVELS THURSDAY...WITH MINIMUM AFTERNOON READINGS ONLY RANGING
BETWEEN 20 AND 35 PERCENT WILL LOWER INTO A 10 TO 25 PERCENT RANGE
OVER THE WEEKEND. OVERNIGHT RECOVERY WILL BE GOOD TO EXCELLENT. WITH
THE DRYING TREND...HIGH TEMPERATURES WILL CLIMB INTO THE WEEKEND
REACHING A 105 TO 110 DEGREE RANGE AT LOWER ELEVATIONS. WINDS WILL
FAVOR A WEST TO SOUTHWEST DIRECTION IN THE AFTERNOON...WITH THE
TYPICAL LIGHT DRAINAGE COMPONENT OVERNIGHT.
&&
.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT ACCORDING TO STANDARD PROCEDURES.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...PERCHA/AJ
AVIATION...NOLTE
FIRE WEATHER...BRECKENRIDGE
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1138 AM EDT TUE SEP 8 2015
LATEST UPDATE...
MESOSCALE DISCUSSION
.MESOSCALE DISCUSSION...
ISSUED AT 1137 AM EDT TUE SEP 8 2015
15Z SURFACE ANALYSIS INDICATED A WARM FRONT AND ASSOCIATED
PRECIPITATION LIFTING NORTH INTO NORTHERN LOWER MICHIGAN. SURFACE
LOW WAS LOCATED OVER SOUTHEAST WISCONSIN. SHOWERS AND THUNDERSTORMS
EXTENDED FROM THE LOW INTO NORTHWEST ILLINOIS ALONG A PREFRONTAL
TROUGH. THIS PRECIPITATION IS TIMED TO MOVE ACROSS SOUTHWEST LOWER
MICHIGAN IN THE 2-3 PM TIMEFRAME.
THE 12Z DTX SOUNDING INDICATED PRECIPITABLE WATER AT 1.93" WHICH IS
NEAR RECORD LEVELS FOR THIS TIME OF YEAR. VISIBLE SATELLITE SUGGESTS
A COUPLE HOUR WINDOW OF CLEARING/DESTABILIZATION NEAR THE I-94
CORRIDOR...WHERE POTENTIAL FOR DAMAGING WINDS WILL BE ELEVATED.
HOWEVER...OVERALL INSTABILITY SHOULD REMAIN MARGINAL...FURTHER
CONTRIBUTING TO AN ENVIRONMENT WITH HIGH PRECIPITATION EFFICIENCIES.
WE ARE LEANING TOWARDS RECENT ESRL EXPERIMENTAL HRRR RUNS THAT
DEPICT AN ADDITIONAL ROUND OF PRECIPITATION SPREADING ACROSS MOST OF
SOUTHERN LOWER MICHIGAN BEHIND THE MENTIONED FIRST WAVE. THIS WOULD
CONTINUE THE PRECIPITATION THREAT WELL INTO EVENING. FIM/GFS/ECMWF
MODELS AGREE ON A STRENGTHENING JET ALOFT BEHIND THE INITIAL WAVE OF
PRECIPITATION...SO FRONTOGENESIS AND ASSOCIATED UPWARD VERTICAL
MOTION ALOFT LOOK PROBABLE AND SUPPORT THE IDEA OF A SECOND BATCH OF
RAIN.
&&
.SYNOPSIS...
ISSUED AT 329 AM EDT TUE SEP 8 2015
PERIODS OF SHOWERS AND THUNDERSTORMS WILL PREVAIL TODAY INTO THIS
EVENING BEFORE A SLOW MOVING COLD FRONT PUSHES THEM SOUTH OF THE
AREA BY MID MORNING WEDNESDAY. AREAS OF LOCALIZED HEAVY RAINFALL
ARE POSSIBLE. IT WILL CONTINUE TO BE VERY HUMID TODAY BUT NOT
QUIET AS WARM AS THE PAST FEW DAY. COOLER AND SIGNIFICANTLY DRIER
AIR WILL FOLLOW THE COLD FRONT FOR WEDNESDAY AND SUNSHINE SHOULD
PREVAIL IN MOST AREAS BY MID AFTERNOON. A SECONDARY COLD FRONT
WILL COME THROUGH THE AREA ON FRIDAY WITH SCATTERED SHOWERS. THIS
COMING WEEKEND SHOULD BE MOSTLY CLEAR WITH MUCH COOLER
TEMPERATURES...HIGHS MAY ONLY REACH THE MID 60S ON SATURDAY.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 329 AM EDT TUE SEP 8 2015
OUR PRIMARY ISSUE CONTINUES TO BE THE THREAT FOR HEAVY RAINFALL.
PRECIPITABLE WATER CONTINUES TO RUN BETWEEN 1.8 AND 2.0 INCHES
OVER MOST OF THE CWA TODAY. THIS IS AROUND 3 TIMES NORMAL AND IS
APPROACHING ALL TIME RECORD VALUES FOR THIS TIME OF YEAR. ADD TO
THAT A FRONTAL BOUNDARY SLOWLY MOVING THROUGH THE AREA...AIDED BY
THE ENTRANCE REGION OF THE POLAR JET AND A SHORTWAVE FROM IOWA...
AND THERE IS LITTLE QUESTION SOME OF THE STORMS WILL PRODUCE
HEAVY RAINFALL. CORFIDI VECTORS WILL BE BELOW 10 MILE PER HOUR
THIS MORNING AND RISE TO AROUND 15 MPH THIS AFTERNOON. THAT TOO
WILL AID IN THE LOCALLY HEAVY RAINFALL. I STILL BELIEVE SOME
ISOLATED RAINFALL AMOUNTS MAY BE CLOSE TO 5 INCHES FROM THIS
EVENT.
WE HAVE THE REMAINS OF YESTERDAYS OUTFLOW BOUNDARY STALLED
BETWEEN I-94 AND I-96 EARLY THIS MORNING. AS THE SHORTWAVE FROM
IOWA MOVES CLOSER TO THIS AREA WILL BE THE FOCUS FOR CONVECTION
THIS MORNING. WHICH SUGGESTS THE STORMS WILL MOSTLY BE SOUTH OF
I-96 AT FIRST BUT THEN LIFT NORTHWARD WITH TIME. BY LATE MORNING
INTO EARLY AFTERNOON I WOULD EXPECT MOST OF THE CONVECTION TO BE
NORTH OF I-96. THEN AS THE PRIMARY COLD FRONT AND SHORTWAVE MOVE
INTO THE AREA.. THE RAP MODEL SHOWS A 30 - 35 KNOT LOW LEVEL JET
MOVING INTO THE AREA BY MID AFTERNOON. THE CORE OF THE SPEED MAX
WILL BE JUST NORTH OF I-96 AND BE EAST OF MKG BY 4 PM AND BE NORTH
OF LANSING BY 8 PM. THIS SUGGEST TO ME THE STRONGEST CONVECTION
WILL BE DURING THE LATE AFTERNOON AND EARLY EVENING.
THERE IS A MARGINAL RISK FOR SEVERE STORMS (SPC) TODAY... WITH THE
NARROW CAPE... AND NUMEROUS HEAVY SHOWERS AROUND... AND ONLY
MARGINAL DEEP LAYER SHEAR... I WOULD IMAGINE ANY SEVERE WEATHER
WOULD BE VERY ISOLATED TODAY.
ONCE THE COLD FRONT COMES THROUGH MOST OF THE CONVECTION WILL EXIT
WITH IT THIS EVENING. HIGH PRESSURE FOLLOWS FOR WEDNESDAY INTO
THURSDAY. CLEARING SKIES FROM NORTHWEST TO SOUTHEAST WEDNESDAY
AFTERNOON. I WOULD EXPECT MOSTLY CLEAR SKIES WEDNESDAY NIGHT INTO
THURSDAY AS THE HIGH MOVES OVERHEAD.
BOTTOM LINE IS WET TODAY...DRY WEDNESDAY AFTERNOON INTO THURSDAY
EVENING.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 329 AM EDT TUE SEP 8 2015
A NICE COOL DOWN IS EXPECTED BY THE END OF THE WEEK AS A DEEP UPPER
TROUGH DEVELOPS OVER THE GREAT LAKES. WE/LL SEE TEMPERATURES IN THE
60S FRIDAY THROUGH SUNDAY ALONG WITH SOME SHOWERS FRIDAY AND
SATURDAY. MODEL CONCERNS ARE SIMILAR TO YESTERDAY AS THE ECMWF
DEEPENS THE LOW AND THEN CUTS IT OFF OVER MICHIGAN SUNDAY WHILE THE
GFS KEEPS THE SYSTEM AN OPEN WAVE AND THEN SCOOTS IT EASTWARD BY
SUNDAY. THE GFS WOULD LEAD TO WARMER TEMPS AND LESS PCPN THAN THE
SLOWER COOLER ECMWF. WE/RE LEANING TOWARD THE GFS SOLUTION AS IT
ALSO LINES UP NICELY WITH THE LATEST FIM. THUS ANY SHOWERS SHOULD
END BY LATE SATURDAY LEADING TO DRY WX SUNDAY AND MONDAY AND WARMER
TEMPS AS RIDGING BUILDS INTO SW LWR MI.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 745 AM EDT TUE SEP 8 2015
CURRENTLY MOSTLY VFR CONDITIONS PREVAIL AT OUR TAF SITES. THERE
IS A BAND OF CONVECTION (WEST TO EAST) LIFTING NORTHWARD HEAD OF
THE SHORTWAVE COMING OUT OF IOWA. THIS BAND OF CONVECTION SHOULD
BE NORTH OF THE TAF STIES BY 16Z OR SO. THEN THE CONVECTION WITH
THE COLD FRONT WILL CROSS THE TAF SITES BETWEEN 22Z AND 03Z FROM
WEST TO EAST. SHOWERS WILL THEN PREVAIL FOR FEW HOURS ONCE THE
COLD FRONT IS THROUGH. ONCE THE SHOWERS END EXPECT A FEW HOURS OF
MVFR CIGS.
&&
.MARINE...
ISSUED AT 329 AM EDT TUE SEP 8 2015
WINDS AND WAVES SHOULD REMAIN BELOW SMALL CRAFT CRITERIA THROUGH
THURSDAY. EVEN SO THERE MAY BE GUSTY WINDS IN SOME OF THE
THUNDERSTORMS TODAY. VISIBILITIES MAY BE REDUCED TO BELOW A HALF
MILE IN SOME OF THE HEAVY THUNDERSTORMS TODAY.
&&
.HYDROLOGY...
ISSUED AT 1142 AM EDT MON SEP 7 2015
WE MAY RUN THE RISK FOR MINOR FLOODING BETWEEN LATE TONIGHT
THROUGH EARLY WEDNESDAY AS HEAVY RAIN IS POISED TO MARCH ACROSS
THE FORECAST AREA.
A SLOW MOVING FRONTAL BOUNDARY WILL BECOME NEARLY STATIONARY LATE
TONIGHT AND DURING THE DAY TUESDAY. FORECAST PRECIPITABLE WATER
VALUES OF AROUND 2.0 INCHES REMAINS UNCHANGED SINCE PRIOR
FORECASTS. TIMING SEEMS TO BE THE MOST CONSISTENT WITH THIS EVENT.
WHILE RAINFALL WILL BE POSSIBLE FROM TONIGHT THROUGH EARLY WEDNESDAY
AFTERNOON...THE HEAVIEST RAIN IS EXPECTED BETWEEN TUESDAY EVENING
AND WEDNESDAY MORNING.
THE ENTIRE FORECAST AREA CAN COUNT ON ABOUT AND INCH OF
PRECIPITATION...WHILE THE HEAVIEST SWATH LANDS NEAR AND NORTH OF
GRAND RAPIDS. 1-3 SEEMS REALISTIC ALONG AND NORTH OF I-96. THE
CATCH HERE IS THAT THE SOUTHERN HALF OF THE FORECAST AREA...SOUTH
OF I-96 REMAINS ENTRENCHED IN THE WARM SECTOR AND COULD EXPERIENCE
HIGHER INSTANTANEOUS RAINFALL RATES. THIS MEANS THAT HEAVY RAINFALL
THAT DEVELOPS IN SOUTHERN SECTIONS OF THE FORECAST AREA...MAY
RESULT IN LOCALIZED HIGHER TOTALS...4-5 INCHES.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
MESOSCALE...TJT
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...99
AVIATION...WDM
HYDROLOGY...JAM
MARINE...WDM
AREA FORECAST DISCUSSION
NWS GAYLORD MI
959 AM EDT TUE SEP 8 2015
.UPDATE...
ISSUED AT 959 AM EDT TUE SEP 8 2015
SHOWERS AND EMBEDDED THUNDERSTORMS ARE STEADILY EXPANDING IN AREAL
COVERAGE ACROSS THE SRN HALF OF OUR CWA LATE THIS MORNING AS DEEP
MOISTURE SURGES NORTH INTO NORTHERN MICHIGAN AHEAD OF A LARGE AREA
OF WIDESPREAD CONVECTION. LATEST DAY 1 OUTLOOK HAS EXPANDED THE
MARGINAL AREA INTO MUCH OF NRN LWR MICHIGAN...ANTICIPATING SOME
DIURNAL DESTABILIZATION THIS AFTERNOON COMBINED WITH SOME INCREASE
IN WIND SPEEDS WELL ALOFT AT THE ANVIL LEVEL. LATEST RAP13 IS
RATHER AGGRESSIVE IN BOOSTING MUCAPES THIS
AFTERNOON...APPROACHING 1700 JOULES IN OUR SE CWA. MEANWHILE...THE
LATEST HRRR SEEMS TO BE UNIMPRESSED WITH THE PROSPECT OF DIURNAL
DESTABILIZATION... SUGGESTING CAPES WILL ONLY REACH TO 250-500
JOULES. LATEST NAM12 LIES SOMEWHERE IN BETWEEN. TEND TO SIDE WITH
THE HRRR GIVEN AMPLE CLOUDS AND PRECIP ACROSS OUR ENTIRE
CWA...INCLUDING OUR SE CWA WHERE THE OTHER TWO MODELS SHOW
GREATEST DESTABILIZATION.
STILL EXPECT SVR CHANCES ARE MINIMAL...BUT WILL CERTAINLY MAINTAIN
CHANCES OF THUNDER ACROSS OUR ENTIRE CWA THRU TODAY AND INTO
EARLY EVENING. WILL ALSO KEEP CATEGORICAL POPS FOR MUCH OF NRN LWR
MICHIGAN...AND WILL KEEP A CLOSE EYE ON ERN UPR MICHIGAN WHERE WE
MAY NEED TO INCREASE POPS FROM LIKELY TO CATEGORICAL AS THIS EVENT
PLAYS OUT TODAY.
&&
.NEAR TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 431 AM EDT TUE SEP 8 2015
...WET DAY AHEAD BUT LAST DAY OF HUMIDITY...
HIGH IMPACT WEATHER POTENTIAL: LOCALLY HEAVY DOWNPOURS POSSIBLE
TODAY.
PATTERN SYNOPSIS/FORECAST: MIDNIGHT SURFACE/COMPOSITE ANALYSIS SHOWS
A COLD FRONT DRAPED ACROSS NORTHEAST/CENTRAL LOWER MICHIGAN AND
EXTENDING BACK ACROSS SOUTHERN LAKE MICHIGAN AND ALONG THE
WISCONSIN/ILLINOIS BORDER INTO SOUTHERN IOWA. SMALL BUBBLE OF HIGH
PRESSURE (1017MB) WAS CENTERED OVER THE MINNESOTA ARROWHEAD. SOUPY
AIR MASS LINGERS OVER THE UPPER LAKES AND POINTS SOUTH AND
SOUTHWEST...GOES PRECIPITABLE WATER ANALYSIS SHOWS AN ARC OF 40-50MM
VALUES FROM THE LOWER LAKES/SOUTHERN LOWER MICHIGAN BACK TO THE MID
MISSISSIPPI VALLEY AND THE EASTERN PLAINS. 00Z APX SOUNDING DOES
SHOW SOME ELEVATED INSTABILITY (ON THE ORDER OF 1200J/KG MUCAPE)...A
FEW SPOTTY SHOWERS HAVE BEEN POPPING UP SOUTH OF M-32 LIKELY
ASSOCIATED WITH WEAK ISENTROPIC ASCENT AS OVERALL WIND FLOW IS LIGHT
BELOW 700MB...WITH A ROUGE SHOWER OVER LUCE COUNTY. MORE WIDESPREAD
RAINFALL HAS BEEN CONGEALING OVER THE MIDWEST.
DIFFUSE FRONT LYING ACROSS LOWER MICHIGAN WILL LIKELY BE MOSTLY
STATIONARY TODAY...BUT WITH PLENTY OF MOISTURE AROUND. STRONGER
SHORT WAVE TROUGH OVER THE ROCKIES WILL PUSH INTO THE UPPER
MIDWEST/UPPER LAKES TONIGHT...WHICH IN TURN WILL ALLOW A SECONDARY
COLD FRONT TO SLICE ACROSS MICHIGAN OVERNIGHT AND FINALLY KNOCK DOWN
THIS PERSISTENTLY HUMID AIR MASS.
PRIMARY FORECAST CONCERNS: DETAILS REGARDING RAINFALL OVER NEXT 24
HOURS.
TODAY...LOOKS LIKE TODAY SHOULD BE RELATIVELY STRAIGHTFORWARD...AS
COMBINATION OF WHAT IS CURRENTLY POPPING OVER LOWER MICHIGAN...AND
ARRIVAL LATER THIS MORNING OF UPSTREAM PRECIPITATION EXPECTED TO
RESULT IN PERIODS OF RAIN...ALONG WITH SOME EMBEDDED THUNDER. AS
HAS BEEN THE CASE RECENTLY...PRECIPITATION SHOULD BE PRETTY
EFFICIENT GIVEN DEEP LAYER MOISTURE (PRECIPITABLE WATER 1.50-2.00
INCHES EXPECTED AND A FAIRLY DEEP WARM LAYER). GENERAL RAINFALL
AMOUNTS OF 0.50-1.00 INCH EXPECTED ACROSS NORTHERN LOWER MICHIGAN...
WITH HIGHER AMOUNTS POSSIBLE DEPENDING ON EVOLUTION OF PRECIPITATION
THOUGH THAT IS SOMEWHAT UNCERTAIN GIVEN RATHER WEAK FOCUSING
MECHANISMS.
TONIGHT...COUPLE ROUNDS OF PRECIPITATION POSSIBLE FOR TONIGHT. LAST
OF THE DAYTIME PRECIPITATION WILL BE PUSHING INTO LAKE HURON DURING
THE MID-LATE EVENING HOURS...AND GIVEN LIGHT FLOW WILL PROBABLY BE
FOLLOWED BY FOG/STRATUS DEVELOPMENT. APPROACH OF SECONDARY COLD
FRONT AND ASSOCIATED SHORT WAVE TROUGH...AS WELL AS RIGHT ENTRANCE
JET FORCING MAY RESULT IN SCATTERED ADDITIONAL DEVELOPMENT AS THIS
FRONT PASSES.
&&
.SHORT TERM...(WEDNESDAY THROUGH THURSDAY NIGHT)
ISSUED AT 431 AM EDT TUE SEP 8 2015
HIGH IMPACT WEATHER: NONE
(9/9)WEDNESDAY...MODELS HAVE COME TOGETHER AND NOW HAVE THE RAIN OUT
OF THE AREA. THE SFC HIGH PRESSURE BUILDS INTO THE LOWER MICHIGAN
AND HOLDS THROUGH THE DAY AND MOST OF THE NIGHT. A SFC TROUGH BEGINS
TO DEVELOP IN RESPONSE TO THE 500 MB SHORTWAVE TROUGH JUST UPSTREAM
IN MINNESOTA, AND ALONG THE THERMAL GRADIENT RUNNING THROUGH LAKE
SUPERIOR, BETWEEN 06Z AND 12Z WHICH BEGINS TO PRODUCE RAIN TO THE
WEST, IN WISCONSIN. AT THIS POINT, IT LOOKS LIKE THE RAIN SHOULD
STAY WEST, AS THE NAM/ECMWF CONTINUE TO KEEP THE SHORTWAVE TROUGH TO
FARTHER WEST THAN THE GFS.
(9/10)THURSDAY...THE SFC RIDGE BREAKS DOWN AS THE 500 MB SHORTWAVE
PUSHES, THE COLD FRONT THROUGH THE REGION. INSTABILITY IS PRETTY
SMALL, AND SINCE WE ALREADY HAVE RAIN SHOWERS WITH A SLIGHT CHANCE
OF THUNDER, WILL KEEP THAT AT THIS POINT, BUT GETTING THE FEELING
WITH THE COOLER SFC TEMPERATURES (IN THE LOWER 70S WEDNESDAY AND
THURSDAY) THAT THERE WON`T BE REALLY ENOUGH INSTABILITY FOR THUNDER.
THEN OVERNIGHT, THE RAIN SHOWERS, OR MAYBE IT WILL JUST BE AN AREA
OF RAIN, SET UPS WAS THE SHORTWAVE AND TROUGH MOVES INTO THE REGION.
AS THE SHORTWAVE PROGRESSIVELY MOVES IN, COLDER 850 MB AIR CONTINUES
INTO THE REGION AS WELL SO THAT WE WILL PROBABLY SET UP LAKE EFFECT
RAIN, ALTHOUGH WITH THE 1000-850 MB LAYER WIND OUT OF THE NORTH-
NORTHEAST, WE`LL STAY OUT OF IT INITIALLY UNTIL FRIDAY.
&&
.LONG TERM...(FRIDAY THROUGH MONDAY)
ISSUED AT 431 AM EDT TUE SEP 8 2015
EXTENDED (FRIDAY THROUGH MONDAY)...THE MODELS ARE BEGINNING TO COME
TOGETHER ON THE EVOLUTION OF THE DIGGING 500 MB SHORTWAVE TROUGH
OVER THE GREAT LAKES. THE ECMWF ISN`T AS DEEP OR CUT OFF AND THE GFS
IS A LITTLE DEEPER. THE ECMWF DOES PUSH THE RAIN THROUGH FASTER AS
WELL AS THE CUT OFF SO THAT THE TIMING THE END OF THE RAIN ON FRIDAY
IS PRETTY CLOSE AND THAT THE COOL DRY WEATHER WILL CONTINUE ON
SATURDAY. SUNDAY, TOO, LOOKS DRY, AND THEN A COLD FRONT PUSHES INTO
THE REGION ON THE GFS SUNDAY NIGHT INTO MONDAY, WHILE THE ECMWF IS
DRY UNTIL MONDAY NIGHT. ONE OTHER CONCERN IS FOR FRIDAY...THERE IS A
LOW END THREAT FOR WATERSPOUTS WITH AN UPPER LOW, DELTA TS OF 16C
AND CLOUD DEPTHS OF 5000-10000 FEET.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 703 AM EDT TUE SEP 8 2015
ANTICIPATED IFR CONDITIONS TO DEVELOP ALL TERMINALS BY MID-LATE
MORNING...FOG/STRATUS WILL BE AN ISSUE AGAIN TONIGHT PRIOR TO
FRONTAL PASSAGE.
&&
.MARINE...
ISSUED AT 431 AM EDT TUE SEP 8 2015
TODAY/TONIGHT...LIGHT WINDS TODAY AND TONIGHT...ONLY MARINE ISSUE
WILL BE POOR VISIBILITY IN FOG.
OUTLOOK...WINDS WILL PICK UP FROM THE NORTHWEST WEDNESDAY BEHIND A
COLD FRONT CROSSING THE UPPER LAKES TUESDAY NIGHT. WINDS WILL BE
GUSTY WITHIN NORTHERN LAKE HURON ZONES WITH COASTAL CONVERGENCE...
MAY BE CLOSE TO SMALL CRAFT CRITERIA.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...MLR
NEAR TERM...JPB
SHORT TERM...JSL
LONG TERM...JSL
MARINE...JPB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
745 AM EDT TUE SEP 8 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 329 AM EDT TUE SEP 8 2015
PERIODS OF SHOWERS AND THUNDERSTORMS WILL PREVAIL TODAY INTO THIS
EVENING BEFORE A SLOW MOVING COLD FRONT PUSHES THEM SOUTH OF THE
AREA BY MID MORNING WEDNESDAY. AREAS OF LOCALIZED HEAVY RAINFALL
ARE POSSIBLE. IT WILL CONTINUE TO BE VERY HUMID TODAY BUT NOT
QUIET AS WARM AS THE PAST FEW DAY. COOLER AND SIGNIFICANTLY DRIER
AIR WILL FOLLOW THE COLD FRONT FOR WEDNESDAY AND SUNSHINE SHOULD
PREVAIL IN MOST AREAS BY MID AFTERNOON. A SECONDARY COLD FRONT
WILL COME THROUGH THE AREA ON FRIDAY WITH SCATTERED SHOWERS. THIS
COMING WEEKEND SHOULD BE MOSTLY CLEAR WITH MUCH COOLER
TEMPERATURES...HIGHS MAY ONLY REACH THE MID 60S ON SATURDAY.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 329 AM EDT TUE SEP 8 2015
OUR PRIMARY ISSUE CONTINUES TO BE THE THREAT FOR HEAVY RAINFALL.
PRECIPITABLE WATER CONTINUES TO RUN BETWEEN 1.8 AND 2.0 INCHES
OVER MOST OF THE CWA TODAY. THIS IS AROUND 3 TIMES NORMAL AND IS
APPROACHING ALL TIME RECORD VALUES FOR THIS TIME OF YEAR. ADD TO
THAT A FRONTAL BOUNDARY SLOWLY MOVING THROUGH THE AREA...AIDED BY
THE ENTRANCE REGION OF THE POLAR JET AND A SHORTWAVE FROM IOWA...
AND THERE IS LITTLE QUESTION SOME OF THE STORMS WILL PRODUCE
HEAVY RAINFALL. CORFIDI VECTORS WILL BE BELOW 10 MILE PER HOUR
THIS MORNING AND RISE TO AROUND 15 MPH THIS AFTERNOON. THAT TOO
WILL AID IN THE LOCALLY HEAVY RAINFALL. I STILL BELIEVE SOME
ISOLATED RAINFALL AMOUNTS MAY BE CLOSE TO 5 INCHES FROM THIS
EVENT.
WE HAVE THE REMAINS OF YESTERDAYS OUTFLOW BOUNDARY STALLED
BETWEEN I-94 AND I-96 EARLY THIS MORNING. AS THE SHORTWAVE FROM
IOWA MOVES CLOSER TO THIS AREA WILL BE THE FOCUS FOR CONVECTION
THIS MORNING. WHICH SUGGESTS THE STORMS WILL MOSTLY BE SOUTH OF
I-96 AT FIRST BUT THEN LIFT NORTHWARD WITH TIME. BY LATE MORNING
INTO EARLY AFTERNOON I WOULD EXPECT MOST OF THE CONVECTION TO BE
NORTH OF I-96. THEN AS THE PRIMARY COLD FRONT AND SHORTWAVE MOVE
INTO THE AREA.. THE RAP MODEL SHOWS A 30 - 35 KNOT LOW LEVEL JET
MOVING INTO THE AREA BY MID AFTERNOON. THE CORE OF THE SPEED MAX
WILL BE JUST NORTH OF I-96 AND BE EAST OF MKG BY 4 PM AND BE NORTH
OF LANSING BY 8 PM. THIS SUGGEST TO ME THE STRONGEST CONVECTION
WILL BE DURING THE LATE AFTERNOON AND EARLY EVENING.
THERE IS A MARGINAL RISK FOR SEVERE STORMS (SPC) TODAY... WITH THE
NARROW CAPE... AND NUMEROUS HEAVY SHOWERS AROUND... AND ONLY
MARGINAL DEEP LAYER SHEAR... I WOULD IMAGINE ANY SEVERE WEATHER
WOULD BE VERY ISOLATED TODAY.
ONCE THE COLD FRONT COMES THROUGH MOST OF THE CONVECTION WILL EXIT
WITH IT THIS EVENING. HIGH PRESSURE FOLLOWS FOR WEDNESDAY INTO
THURSDAY. CLEARING SKIES FROM NORTHWEST TO SOUTHEAST WEDNESDAY
AFTERNOON. I WOULD EXPECT MOSTLY CLEAR SKIES WEDNESDAY NIGHT INTO
THURSDAY AS THE HIGH MOVES OVERHEAD.
BOTTOM LINE IS WET TODAY...DRY WEDNESDAY AFTERNOON INTO THURSDAY
EVENING.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 329 AM EDT TUE SEP 8 2015
A NICE COOL DOWN IS EXPECTED BY THE END OF THE WEEK AS A DEEP UPPER
TROUGH DEVELOPS OVER THE GREAT LAKES. WE/LL SEE TEMPERATURES IN THE
60S FRIDAY THROUGH SUNDAY ALONG WITH SOME SHOWERS FRIDAY AND
SATURDAY. MODEL CONCERNS ARE SIMILAR TO YESTERDAY AS THE ECMWF
DEEPENS THE LOW AND THEN CUTS IT OFF OVER MICHIGAN SUNDAY WHILE THE
GFS KEEPS THE SYSTEM AN OPEN WAVE AND THEN SCOOTS IT EASTWARD BY
SUNDAY. THE GFS WOULD LEAD TO WARMER TEMPS AND LESS PCPN THAN THE
SLOWER COOLER ECMWF. WE/RE LEANING TOWARD THE GFS SOLUTION AS IT
ALSO LINES UP NICELY WITH THE LATEST FIM. THUS ANY SHOWERS SHOULD
END BY LATE SATURDAY LEADING TO DRY WX SUNDAY AND MONDAY AND WARMER
TEMPS AS RIDGING BUILDS INTO SW LWR MI.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 745 AM EDT TUE SEP 8 2015
CURRENTLY MOSTLY VFR CONDITIONS PREVAIL AT OUR TAF SITES. THERE
IS A BAND OF CONVECTION (WEST TO EAST) LIFTING NORTHWARD HEAD OF
THE SHORTWAVE COMING OUT OF IOWA. THIS BAND OF CONVECTION SHOULD
BE NORTH OF THE TAF STIES BY 16Z OR SO. THEN THE CONVECTION WITH
THE COLD FRONT WILL CROSS THE TAF SITES BETWEEN 22Z AND 03Z FROM
WEST TO EAST. SHOWERS WILL THEN PREVAIL FOR FEW HOURS ONCE THE
COLD FRONT IS THROUGH. ONCE THE SHOWERS END EXPECT A FEW HOURS OF
MVFR CIGS.
&&
.MARINE...
ISSUED AT 329 AM EDT TUE SEP 8 2015
WINDS AND WAVES SHOULD REMAIN BELOW SMALL CRAFT CRITERIA THROUGH
THURSDAY. EVEN SO THERE MAY BE GUSTY WINDS IN SOME OF THE
THUNDERSTORMS TODAY. VISIBILITIES MAY BE REDUCED TO BELOW A HALF
MILE IN SOME OF THE HEAVY THUNDERSTORMS TODAY.
&&
.HYDROLOGY...
ISSUED AT 1142 AM EDT MON SEP 7 2015
WE MAY RUN THE RISK FOR MINOR FLOODING BETWEEN LATE TONIGHT
THROUGH EARLY WEDNESDAY AS HEAVY RAIN IS POISED TO MARCH ACROSS
THE FORECAST AREA.
A SLOW MOVING FRONTAL BOUNDARY WILL BECOME NEARLY STATIONARY LATE
TONIGHT AND DURING THE DAY TUESDAY. FORECAST PRECIPITABLE WATER
VALUES OF AROUND 2.0 INCHES REMAINS UNCHANGED SINCE PRIOR
FORECASTS. TIMING SEEMS TO BE THE MOST CONSISTENT WITH THIS EVENT.
WHILE RAINFALL WILL BE POSSIBLE FROM TONIGHT THROUGH EARLY WEDNESDAY
AFTERNOON...THE HEAVIEST RAIN IS EXPECTED BETWEEN TUESDAY EVENING
AND WEDNESDAY MORNING.
THE ENTIRE FORECAST AREA CAN COUNT ON ABOUT AND INCH OF
PRECIPITATION...WHILE THE HEAVIEST SWATH LANDS NEAR AND NORTH OF
GRAND RAPIDS. 1-3 SEEMS REALISTIC ALONG AND NORTH OF I-96. THE
CATCH HERE IS THAT THE SOUTHERN HALF OF THE FORECAST AREA...SOUTH
OF I-96 REMAINS ENTRENCHED IN THE WARM SECTOR AND COULD EXPERIENCE
HIGHER INSTANTANEOUS RAINFALL RATES. THIS MEANS THAT HEAVY RAINFALL
THAT DEVELOPS IN SOUTHERN SECTIONS OF THE FORECAST AREA...MAY
RESULT IN LOCALIZED HIGHER TOTALS...4-5 INCHES.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...99
AVIATION...WDM
HYDROLOGY...JAM
MARINE...WDM
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
731 AM EDT TUE SEP 8 2015
.AVIATION...
SHOWERS WITH EMBEDDED THUNDER WILL PERSIST TO SOME DEGREE FOR
KFNT/KMBS THROUGH MUCH OF THE MORNING AND EARLY AFTN WITH A SLIGHT
INCREASE IN COVERAGE POSSIBLE WITH THE INTRODUCTION OF DIURNAL
HEATING. DETROIT AREA SITES ARE EXPECTED TO REMAIN LARGELY
DRY...THOUGH AN ISOLATED TSTORM CANNOT BE RULED OUT...UNTIL FROPA
LATE TONIGHT. SUFFICIENT DRY AIR NEAR THE SURFACE WILL SUSTAIN VFR
CONDITIONS AWAY FROM SHOWER ACTIVITY. IN AND NEAR SHOWERS...UPSTREAM
OBS HAVE SUGGESTED A HIGH PROBABILITY OF MVFR.
FOR DTW...CEILING DEVELOPMENT AROUND 5KFT WILL BE POSSIBLE FOR
MIXING UP TO 6KFT DURING THE AFTERNOON. A PARTIAL COVERAGE OF
SHOWERS...PERHAPS A TSTORM...WILL BE POSSIBLE DURING PEAK HEATING
BUT ATTM CONFIDENCE IN BOTH OCCURRENCE AND COVERAGE ARE TOO LOW TO
WARRANT A MENTION IN THE TAFS. SHOWERS WILL MOVE THROUGH LATE
TONIGHT BRINGING LOW MVFR TO IFR.
//DTW THRESHOLD PROBABILITIES...
* LOW FOR TSTORMS IMPACTING KDTW AIRSPACE
* MEDIUM FOR CIGS AOB 5KFT.
&&
.PREV DISCUSSION...ISSUED 340 AM EDT TUE SEP 8 2015
SHORT TERM...TODAY AND TONIGHT
ABSENT FORCING, THE RESERVOIR OF SIGNIFICANT MOISTURE ABOVE 700MB ON
LAST NIGHT`S 00Z DTX SOUNDING REMAINED QUIET THROUGH ABOUT 06Z.
HOWEVER, WARM ADVECTION WITHIN STRENGTHENING SWLY FLOW BEGAN TO
IGNITE CONVECTION ROUGHLY ALONG A CHICAGO TO PORT HURON LINE BY 07Z.
CONDITIONS WILL REMAIN FAVORABLE FOR EXPANSION OF THIS ACTIVITY
THROUGH THE MORNING AS FLOW CONTINUES TO INCREASE AND DAYTIME
HEATING ADDS A FEW HUNDRED J/KG CAPE TO THE PROFILE. THROUGH 18Z,
CONVECTION IS EXPECTED TO BE CONFINED MAINLY NORTH OF M59 ALONG WITH
THE BETTER FORCING. PWATS AROUND 2", LOW DENSITY CAPE, AND AN
INCREASINGLY DEEP WARM CLOUD LAYER WILL SUPPORT A HEAVY RAIN THREAT
FOR ANY AREAS THAT RECEIVE RAIN THROUGH TONIGHT. LOCALIZED FLOODING
IS NOT OUT OF THE QUESTION GIVEN SLOWER STORM MOTION AND THE
POTENTIAL FOR SOME AREAS ACROSS THE NORTHWEST TO SEE MULTIPLE ROUNDS
OF RAINFALL.
A SECOND AND STRONGER LLJ SURGE WILL ARRIVE BY AFTERNOON IN ADVANCE
OF THE SHORTWAVE NOTED OVER NORTHWEST MISSOURI AT 07Z THIS MORNING.
DYNAMIC FORCING WILL BE STOUT, BUT WILL ONLY OCCUR OVER A RELATIVELY
SMALL SPATIAL FOOTPRINT, MOST OF WHICH WILL BE OVER WESTERN AND
NORTHERN LOWER. HOWEVER, 06Z RAP INDICATES THAT THE CORE OF THE
ASSOCIATED 35-40KT LLJ WILL ALIGN ALONG A MUSKEGON TO WEST BRANCH
LINE 21-00Z WHICH WILL PUT THE SAGINAW VALLEY IN LINE TO RECEIVE A
NOTEWORTHY BOOST IN FORCING DUE TO DIFFERENTIAL WARM ADVECTION LATE
IN THE PEAK HEATING PERIOD. THUS, EVEN IF THE STRONGER DYNAMIC
FORCING DOES MANAGE TO MISS THE CWA...AND AT THIS TIME IT`S PROGGED
TO JUST GRAZE THE SAGINAW VALLEY AREA...NORTHWESTERN AREAS SHOULD
STILL SEE SOME EASTWARD EXPANSION OF CONVECTION DURING THE MID TO
LATE AFTERNOON DUE TO THE STRENGTHENING LLJ.
THE BULK OF THE RAIN SHIELD WILL EVENTUALLY PEEL NORTH ALONG WITH
THE DEPARTING WAVE, BUT LARGER SCALE FORCING EMBEDDED WITHIN THE
RIGHT ENTRANCE OF A 130KT UPPER JET OVER LAKE SUPERIOR WILL SUPPORT
A WAVE OF SHOWERS SLOWLY TRAVERSING THE REMAINDER OF THE AREA
ROUGHLY 00Z-12Z WED. THESE, TOO, WILL CARRY THE SAME THREAT FOR
HEAVY RAIN, THOUGH A DIMINISHED THREAT FOR FLOODING WILL EXIST DUE
TO INCREASINGLY PROGRESSIVE LARGER SCALE FORCING.
LONG TERM...
A STRONG WAVE ENTERING THE BASE OF THE MID/UPPER LEVEL TROUGH
CENTERED OVER WESTERN ONTARIO WILL PROVIDE THE NEEDED BOOST TO
USHER THE LINGERING FRONTAL BOUNDARY OFF TO THE EAST WEDNESDAY.
TIMING IS STILL NOT IRONED OUT EXACTLY AS THE INCOMING WESTERLY
JET MAX TURNS MORE NORTHEASTERLY ONCE IT PHASES WITH THE EXISTING
JET ALIGNED WITH THE FRONT. SO EXPECT THE FRONT TO BECOME MORE
PROGRESSIVE AS THE PARENT SYSTEM GAINS SPEED...BUT WITH THE SE
RIDGE STILL REACHING UP INTO THE EASTERN GREAT LAKES WE CAN EXPECT
SHOWERS TO LINGER OVER THE EASTERN COUNTIES INTO THE AFTERNOON
HOURS WEDNESDAY. THE FRONT WILL PUSH THE ENHANCED RIBBON OF
MOISTURE...NEAR 2 INCH PWATS...OFF TO THE EAST BY MIDDAY WEDNESDAY
BUT RESIDUAL MOISTURE POOL BETWEEN 1- 1.5 INCHES WILL STILL LINGER
THROUGH THE AFTERNOON UNTIL A SECONDARY TROUGH DROPS THROUGH LOWER
MI. THE NAM IS VERY BULLISH ON GENERATING SHOWERS WITH THIS
SECONDARY TROUGH IN PART DUE TO ELEVATED LL LAPSE RATES IN THE
WAKE OF THE FRONT. THERE IS SOME SIGNAL IN THE EURO/GFS BUT WITH
THE STRENGTH OF THE FRONTAL CIRCULATION...EXPECT A GOOD DEAL OF
SUBSIDENCE IN ITS WAKE COMBINED WITH THE BUILDING RIDGE. IN
ADDITION...THE NAM HAS BEEN DEVELOPING A SFC LOW ALONG THE FRONT
PASSING JUST TO OUR SOUTH THROUGH TOLEDO WEDNESDAY
AFTERNOON/EVENING. THIS WOULD RESULT IN ADDITIONAL DEFORMATION
FORCING LINGERING OVER SE MI AFTER 00Z THURSDAY. BUT AGAIN...NO
OTHER MODEL HAS ANYTHING NEARLY AS ORGANIZED AT THIS TIME.
SOMETHING TO WATCH BUT IN THE MEANTIME...FORECAST WILL FEATURE
CHANCE POPS DECREASING THROUGH THE DAY FROM NORTHWEST TO
SOUTHEAST.
WITH THE FRONT TO OUR SOUTH...PRECIP AND OVERCAST SKIES...HIGH
TEMPERATURES WILL TAKE A NOTABLE DIVE WEDNESDAY TOPPING OUT IN THE
UPPER 70S. THE SECONDARY TROUGH LATE WEDNESDAY WILL BRING ABOUT
COOLER WEATHER WITH NORTHERLY FLOW DROPPING HIGHS INTO THE MID 70S
FOR THURSDAY. TEMPS WILL TAKE A FURTHER NOSE DIVE INTO THE WEEKEND
AS YET ANOTHER FRONT SWEEPS THROUGH THE REGION ON FRIDAY BRINGING
THE NEXT CHANCE OF PRECIP WITH IT. MID MI MAY SEE SOME PRECIP
THURSDAY/THURSDAY NIGHT AS IT DRAPES SW TO NE THROUGH NORTHERN
LOWER...BUT MOST OF SE MI WILL REMAIN DRY TIL FRIDAY. MODELS DIVERGE
QUITE A BIT FOR THE WEEKEND IN THE HANDLING OF THIS NEXT UPPER
TROUGH...BUT CONSENSUS IS TROUGHING WILL HOLD OVER THE REGION WITH
ADDITIONAL SHOTS OF COOLER AIR WITH EACH FRONT. 850MB COLD POOL WILL
SET UP OVER THE GREAT LAKES WITH TEMPS POTENTIALLY DOWN INTO THE MID
SINGLE DIGITS AS HIGH PRESSURE SETTLES OVER THE REGION FROM CANADA.
MARINE...
A COLD FRONT DRAPED ACROSS THE CENTRAL GREAT LAKES IS RESULTING IN
WEAK FLOW WITHIN THE TROUGH OF LOW PRESSURE. THE EXCEPTION WOULD BE
LAKE ERIE AND LAKE ST CLAIR WHOM WILL CONTINUE TO RESIDE IN THE
SOUTHWESTERLY FLOW IN ADVANCE OF THE FRONT THROUGH THIS EVENING. THE
FRONT WILL BRING ABOUT A NOTABLE WIND SHIFT TONIGHT OVER LAKE HURON
TO NORTHWESTERLY...WHILE A TIGHTENED GRADIENT PROVIDES A BOOST TO
WIND SPEEDS WHICH WILL RANGE BETWEEN 20 AND 25 KNOTS POST COLD
FRONT. THIS FLOW WILL CONTINUE THROUGH WEDNESDAY AND WEDNESDAY NIGHT
AS A SECONDARY FRONT THEN DROPS THROUGH THE REGION. HIGH PRESSURE
WILL ALLOW WINDS TO RELAX ON THURSDAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....JVC
SHORT TERM...JVC
LONG TERM....DRK
MARINE.......DRK
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DULUTH MN
647 AM CDT TUE SEP 8 2015
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 331 AM CDT TUE SEP 8 2015
AT 330 AM...SKIES WERE PARTLY TO MOSTLY CLOUDY ACROSS THE
NORTHLAND. THERE WERE A FEW LIGHT RAIN SHOWERS OR SPRINKLES ACROSS
NW WI...WITH A LARGE AREA OF SHOWERS AND THUNDERSTORMS SOUTH AND
WEST OF THE CWA. TEMPERATURES RANGED FROM NEAR 50 ACROSS THE NORTH
TO THE LOWER 60S IN PORTIONS OF NW WI. WINDS WERE GENERALLY LIGHT.
THE MAIN FOCUS FOR TODAY WILL BE THE POTENTIAL FOR SHOWERS AND
THUNDERSTORMS...ESPECIALLY ACROSS NW WI. THE RAP SEEMS TO HAVE THE
BEST HANDLE ON THE CURRENT TRENDS ACROSS THE UPPER MIDWEST. HAVE
INCREASED POPS ACROSS NW WI THIS MORNING AND WILL HAVE TO KEEP A
CLOSE EYE ON THE CONVECTION STREAMING NORTHEAST FROM SOUTHERN MN.
MAY NEED TO INCREASE POPS EVEN FURTHER DEPENDING ON THE EVOLUTION
OF THE COMPLEX TO OUR SOUTH AS A SHORTWAVE LIFTS TO THE NORTH AND
EAST DURING THE MORNING. THE CHANCE OF PRECIPITATION WILL
GENERALLY INCREASE OVERNIGHT AND EARLY TODAY...AND THEN DECREASE
FROM LATE MORNING THROUGH THIS AFTERNOON. SKIES SHOULD BECOME
PARTLY TO MOSTLY SUNNY ACROSS THE AREA. HIGHS WILL BE IN THE 70S.
WITH CLEAR TO PARTLY CLOUDY SKIES AND HIGH PRESSURE SETTING IN
TONIGHT...WE SHOULD SEE OVERNIGHT LOWS LARGELY IN THE 40S.
WEST TO NORTHWEST FLOW ON WEDNESDAY WILL BRING A COUPLE AREAS OF
POSSIBLE PRECIPITATION AS THE DAY WEARS ON. THE FIRST WILL BE
ACROSS THE NORTH...AS A COLD FRONT DROPS SOUTHWARD ACROSS THE
INTERNATIONAL BORDER. ANOTHER WILL BE FURTHER SOUTH FROM EAST
CENTRAL MN INTO NORTHERN WISCONSIN...AS SHOWERS AND POSSIBLY EVEN
SOME THUNDERSTORMS DEVELOP IN THE AFTERNOON. THE COLD FRONT SHOULD
BE GENERALLY ACROSS THAT AREA BY LATE IN THE DAY. TEMPS WILL BE A
BIT COOLER ON WEDNESDAY...RANGING FROM THE MID 60S NORTH TO THE
LOWER TO MIDDLE 70S SOUTH.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 331 AM CDT TUE SEP 8 2015
THE UPPER PATTERN WILL FEATURE AN UPPER LOW OVER HUDSON BAY EARLY IN
THE PERIOD WITH A TROUGH EXTENDING SOUTH INTO THE NORTHLAND. THE LOW
WILL MOVE EAST THROUGH THE PERIOD WITH NORTHWEST FLOW DEVELOPING.
FINALLY LATE IN THE WEEKEND/EARLY NEXT WEEK THE FLOW WILL BECOME
MORE ZONAL.
SEVERAL SHORTWAVES WILL MOVE THROUGH THE REGION BRINGING A CHANCE
FOR SHOWERS AND PERHAPS A THUNDERSTORM WEDNESDAY NIGHT THROUGH
FRIDAY AND AGAIN MONDAY/TUESDAY. AT THIS TIME...THESE SYSTEMS DO NOT
LOOK PARTICULARLY STRONG WITH THE EXCEPTION OF WEDNESDAY
NIGHT/THURSDAY. THE ECMWF IS SHOWING HIGHER RAINFALL OVER OUR
SOUTHERN ZONES WHICH IS NOT OUT OF THE QUESTION AS THERE SHOULD BE
SOME FGEN FORCING AS THE UPPER WAVE MOVES THROUGH. WE INCREASED POPS
OVER SOUTHERN AREAS A BIT...AND MAY HAVE TO INCREASE QUITE A BIT IF
BETTER AGREEMENT OCCURS AMONG THE MODELS.
TEMPERATURES WILL BE A FEW DEGREES COOLER THAN NORMAL
THURSDAY/FRIDAY/SATURDAY...THEN MODERATE BRIEFLY SUNDAY BEFORE
FALLING BELOW NORMAL AGAIN BY TUESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 638 AM CDT TUE SEP 8 2015
VFR CONDITIONS COVERED MUCH OF THE NORTHLAND...WITH SOME PATCHY
FOG PRODUCING IFR CONDITIONS. THE FOG WILL LIFT BETWEEN 8 AM AND
9 AM. LIGHT RAIN WAS FALLING OVER PORTIONS OF NORTHWEST WISCONSIN
WITH A FEW SPOTTY SHOWERS OVER PINE COUNTY. THE RAIN SHOULD BE
DIMINISHING THIS MORNING LEADING TO VFR CONDITIONS THROUGH THE
REST OF THE PERIOD.
GUSTY WEST/NORTHWEST WINDS WILL DEVELOP MOST AREAS LATE THIS
MORNING/EARLY AFTERNOON...THEN SUBSIDE EARLY THIS EVENING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 74 49 71 50 / 10 0 20 20
INL 69 43 66 40 / 10 10 20 20
BRD 74 48 73 49 / 10 0 20 30
HYR 77 44 73 49 / 20 0 30 30
ASX 79 48 75 49 / 10 0 20 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...NONE.
&&
$$
SHORT TERM...DAP
LONG TERM...MELDE
AVIATION...MELDE
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
1001 AM CDT TUE SEP 8 2015
.UPDATE...DECIDED TO BRIDGE POPS ACROSS THE NULL AREA OVER THE CENTRAL
SECTIONS OF THE CWA FOR THIS AFTERNOON. DESPITE COLD CORE LOW OVER
THE NORTH CENTRAL GULF PULLING AWAY TO THE SW...DEEPER TROPICAL
MOISTURE FILLING IN FROM AL SHOULD BE SUFFICIENT FOR HEATING TO
SPECKLE IN SOME ISOLATED CONVECTION BY LATE AFTERNOON. THE HRRR HAS
A SCENARIO SIMILAR TO THIS AS WELL. TEMPS AND THE REST OF THE
FORECAST APPEARS ON TRACK./26/
&&
.AVIATION...VFR CONDITIONS WILL PREVAIL THROUGH WEDNESDAY. AFTN/EVNG
SHRA/TSRA COVERAGE WILL BE SPARSE AND IT IS VERY UNLIKELY THAT A TAF
SITE WILL BE IMPACTED. THERE WILL BE THE TYPICAL PATCHY AREAS OF
MVFR CATEGORY FOG DURING THE 09-14Z TIME FRAME...PARTICULARLY IN THE
HBG AREA. /EC/
&&
.PREV DISCUSSION... /ISSUED 436 AM CDT TUE SEP 8 2015/
SHORT TERM...TODAY THOUGH WEDNESDAY NIGHT...THE UPPER LOW IS
CURRENTLY SITUATED DIRECTLY SOUTH OF THE CWA ALONG THE GULF COAST
THIS MORNING WITH A SMALL SURFACE LOW PRODUCING CONVECTION JUST TO
THE EAST OF THAT OFF THE COAST OF THE FLORIDA PANHANDLE. THERE IS
QUITE THE MID LAYER SHEAR AXIS VISIBLE WHEN LOOKING AT THE VAD WINDS
THIS MORNING. A 60-70 KT JET APPEARS TO BE OVER THE CWA THIS MORNING
VIA OTHER UPPER AIR ANALYSIS. THE CONVERGENT LEFT ENTRANCE REGION OF
THIS FEATURE WILL BE THE FOCUS OF ANY AFTERNOON CONVECTION TODAY. THE
MAJORITY OF MODELS SHOW THIS CONVECTION REMAINING EAST OF OUR AREA.
THEREFORE POPS ARE RELATIVELY LOW TODAY EXCEPT FOR ALONG THE MS/AL
BORDER WHICH MAY SEE AN ISOLATED SHOWER/STORM THIS AFTERNOON. HIGH
TEMPERATURES WILL BE ABOVE NORMAL AGAIN AND VERY SIMILAR TO
YESTERDAY.
ON WEDNESDAY, AN UPPER TROUGH WILL BEGIN MAKING ITS WAY EAST. THE
ASSOCIATED FRONT WILL APPROACH THE AREA BUT DO NOT REALLY EXPECT IT
TO ENTER THE CWA UNTIL WEDNESDAY NIGHT/THURSDAY MORNING. WEDNESDAY
POPS WILL CONTINUE TO VARY BASED ON THE TIMING OF THIS FRONT. AS OF
NOW, AFTERNOON CONVECTION IS STILL EXPECTED OUT AHEAD OF THE FRONT
AND WILL BE FOCUSED MOSTLY EAST OF I-55. THE POTENTIAL FOR HAZARDOUS
WEATHER APPEARS TO PRETTY LOW FOR THIS TIMEFRAME FOR NOW. /10/
LONG TERM...THURSDAY THROUGH MONDAY...A COOLER AND WETTER START TO
THE LONG TERM PERIOD IS EXPECTED THURSDAY AS UPPER LEVEL TROUGHING
LINGERS OVER OUR REGION. THIS TROUGH WILL COMBINE WITH A MOIST AIR
MASS WITH A PWAT AROUND 2 INCHES AND DAYTIME HEATING TO RESULT IN
NUMEROUS STORMS. THE CLOUD COVER AND ASSOCIATED RAIN DEVELOPMENT
WILL HELP HOLD AFTERNOON HIGHS IN THE MID TO UPPER 80S OVER MOST OF
OUR AREA. NORMAL AFTERNOON HIGHS RUN IN THE UPPER 80S. MODELS AGREE
THAT ANOTHER MORE POTENT SHORTWAVE WILL BEGIN DEEPENING A BROAD
TROUGH OVER THE EASTERN CONUS FRIDAY INTO SATURDAY. THE GFS REMAINS
WEAKER WITH THE SHORTWAVE AND UPPER LEVEL TROUGH THAN THE CANADIAN
AND ECMWF WHICH CLOSE A LOW OFF OVER THE GREAT LAKES REGION BY
SATURDAY MORNING. DECENT RAIN CHANCES ARE EXPECTED FRIDAY AS THE
DEEPENING UPPER LEVEL TROUGH IS EXPECTED TO SUPPORT A COLD FRONT
THAT IS EXPECTED TO DROP INTO OUR CWA FRIDAY BUT SIDING WITH THE
ECMWF/CANADIAN...A DRIER WEEKEND LOOKS TO BE ON TAP. THE COLD FRONT
IS EXPECTED TO CLEAR OUR CWA SATURDAY AFTERNOON. A >1020MB SURFACE
HIGH WILL DROP OVER THE CENTRAL PLAINS AND HELP USHER IN A COOLER
AND DRIER AIR MASS INTO OUR CWA. DEW POINTS WILL DROP INTO THE 50S
WITH PWATS KNOCKED DOWN TO AROUND ONE INCH. UPPER LEVEL TROUGHING
WILL CONTINUE OVER OUR REGION THROUGH MONDAY BUT THE SURFACE HIGH
WILL REMAIN CENTERED NORTH OF OUR CWA AS IT TRACKS ACROSS THE
TENNESSEE AND OHIO VALLEYS BY MONDAY. THIS WILL KEEP THE GULF
CLOSED LIMITING CONVECTIVE POTENTIAL OVER OUR CWA. /22/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 95 71 92 71 / 17 10 27 26
MERIDIAN 90 69 92 70 / 21 13 28 20
VICKSBURG 94 70 93 71 / 17 6 29 34
HATTIESBURG 92 71 92 71 / 25 16 27 17
NATCHEZ 93 71 92 71 / 21 9 23 28
GREENVILLE 95 72 91 72 / 9 9 37 47
GREENWOOD 94 71 92 71 / 13 7 33 43
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
26/EC
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
902 AM MDT TUE SEP 8 2015
.UPDATE...
A FEW CLOUDS WILL MOVE ACROSS THE FORECAST AREA TODAY.
OTHERWISE...SKIES WILL BE MOSTLY SUNNY WITH TEMPERATURES WARMING
CLOSE TO NORMAL FOR THIS TIME OF YEAR. PREVIOUS DISCUSSION AND
CURRENT FORECAST LOOKS TO BE IN GOOD SHAPE. THEREFORE...NO UPDATES
ARE PLANNED FOR TODAY. HOOLEY
&&
.SHORT TERM...VALID FOR TDY AND WED...
DRY AND SEASONABLY WARM WEATHER IS EXPECTED TODAY AND WEDNESDAY
WITH JUST A BIT OF AN AFTERNOON BREEZE IN MOST LOCATIONS.
AS OF 0830 UTC...LIGHT RAIN SHOWERS IN SOUTHEASTERN MT ASSOCIATED
WITH MODEST MID-LEVEL FRONTOGENESIS AND A PASSING SHORTWAVE TROUGH
ARE SHOWING SIGNS OF DECAY. TIME-LAGGED HRRR SIMULATIONS FROM BOTH
THE OPERATIONAL AND EXPERIMENTAL VERSION OF THE MODEL SUGGEST THAT
THESE SHOWERS WILL BE COMPLETELY GONE BY ABOUT 12 UTC AND THE REST
OF THE 00 UTC GUIDANCE AGREES...SO WE HAVE STARTED THE DAY WITH A
DRY FORECAST EVERYWHERE AFTER SUNRISE.
FOR TODAY...DRY NORTHWEST FLOW WILL PREVAIL ALOFT AND LOOKS DEVOID
OF ADDITIONAL SHORTWAVE TROUGHS OF ANY SIGNIFICANCE...SO WE EXPECT
A QUIET DAY. FORECAST SOUNDINGS SUPPORT MIXING TO ABOUT 650-MB IN
MOST AREAS AND WITH A BIT OF WARMING ALOFT HIGHS WILL TAKE A STEP
UPWARD FROM YESTERDAY...WITH FORECAST VALUES WELL INTO THE 70S F.
HUMIDITIES WILL FALL TO BETWEEN 15 AND 20 PERCENT IN SOUTH CENTRAL
MT AND PERHAPS NORTH CENTRAL WY THIS AFTERNOON...AND THERMAL GUSTS
TO 30 MPH ARE LIKELY IN THE LIVINGSTON AND BIG TIMBER AREAS DURING
PEAK HEATING WHEN THE BOUNDARY LAYER IS DEEPEST. THAT WILL PRODUCE
ELEVATED FIRE DANGER IN THAT AREA FOR A FEW HOURS THIS AFTERNOON.
TONIGHT...LOWS WILL BE IN THE 40S TO AROUND 50 F AS DRY NORTHWEST
FLOW CONTINUES ALOFT.
WEDNESDAY...THE 00 UTC GUIDANCE SHOWS A WEAK SURFACE LOW DROPPING
INTO ND DURING THE DAY...PLACING SOUTHERN MT AND NORTHERN WY IN
THE WARM SECTOR OF THAT FEATURE AHEAD OF A SOUTHWARD-MOVING COOL
FRONT. THIS SCENARIO WILL LIKELY ENHANCE THE EFFICIENCY OF LOW-
LEVEL TURBULENT MIXING...SO WE HAVE LEANED TOWARD THE WARMER SIDE
OF THE 00 UTC MODEL GUIDANCE FOR FORECAST HIGHS AROUND 80 F OVER
MOST OF THE AREA. WE LEFT A DRY FORECAST IN PLACE WEDNESDAY NIGHT
EVEN AS THE COOL FRONT SETTLES ACROSS THE AREA GIVEN THE LACK OF
APPRECIABLE FORCING ALOFT IN MOST 00 UTC MODEL SOLUTIONS. SCHULTZ
.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...
AN UPPER RIDGE GRADUALLY BUILDS INTO THE NORTHERN ROCKIES THROUGH
THE END OF THE WEEK UNDER WEAKENING NORTHWEST FLOW ALOFT. THIS
WILL KEEP THE FORECAST DRY AND PROMOTE WARMER TEMPERATURES INTO
THE EARLY PART OF THE WEEKEND. IN FACT...TEMPERATURES LOOK TO
APPROACH 90 DEGREES ON SATURDAY. MODELS LOWER HEIGHTS SOME SUNDAY
INTO MONDAY AS A COLD FRONT MOVES THROUGH. THIS FRONT IS PROGGED
WEAKER THAN THE LAST SEVERAL MODEL RUNS. GUIDANCE NOW ONLY LOWERS
HIGHS TO THE MID 70S ON MONDAY...WHICH ARE CLIMATE AVERAGES. HAVE
INCLUDED CHANCE POPS STARTING SUNDAY NIGHT WITH THE COLD FRONT AND
LINGERING THEM INTO EARLY NEXT WEEK WITH LOWERING HEIGHTS AND WEAK
ENERGY STREAMING IN FROM THE WEST.
IT SHOULD BE NOTED THAT BEYOND MONDAY...MODELS DIVERGE FOR THE
WEATHER PATTERN INTO THE MIDDLE OF NEXT WEEK. THE GFS WAS MORE
AGGRESSIVE ON A TROUGH SLIDING INTO MONTANA FROM THE NORTHWEST
PROVIDING A DECENT COOL DOWN. THE ECMWF WEAKENS THE TROUGH
TREMENDOUSLY OVER BRITISH COLUMBIA AND ACTUALLY DEVELOPS SOUTHWEST
FLOW OVER THE GREAT BASIN...FOR A MUCH WARMER REGIME. THE ECMWF
HAS NOT BEEN CONSISTENT OF LATE BEYOND 180 HOURS AND GREATLY
HESITATE FOLLOWING IT. THAT BEING SAID...THE GFS HAS BACKED OFF
QUITE A BIT ON THE DEPTH OF THE TROUGH FOR TUESDAY AS WELL.
INDICATIONS SEEM TO BE POINTING AWAY FROM A STRONG COOL DOWN NEXT
WEEK. WILL CONTINUE TO MONITOR. TWH
&&
.AVIATION...
VFR CONDITIONS ANTICIPATED TODAY. WEST TO NORTHWEST WINDS WILL
INCREASE THIS AFTERNOON AS THE DAY HEATS UP. SOME GUSTS TO 25 KTS
CAN BE EXPECTED AT KLVM WITH GUSTS NEAR 20 AND 15 KTS NEAR KBIL
AND KMLS...RESPECTIVELY. KSHR SHOULD REMAIN IN WEAK FLOW THROUGH
THE DAY. MROWELL
&&
.PRELIMINARY POINT TEMP/POPS...
TDY WED THU FRI SAT SUN MON
-------------------------------------------------------
BIL 076 051/080 050/078 050/081 052/087 056/084 050/075
0/B 00/B 10/U 11/U 00/U 01/U 22/W
LVM 076 045/081 046/080 045/082 048/086 049/083 048/077
1/N 00/B 10/U 00/U 00/U 11/U 23/W
HDN 078 048/082 049/079 048/082 050/088 053/085 049/079
1/B 00/B 11/B 11/U 00/U 01/U 22/W
MLS 075 051/079 050/076 049/079 052/086 055/084 049/075
1/B 00/B 11/B 11/U 00/U 00/U 22/W
4BQ 074 050/079 051/076 049/079 051/085 054/086 052/077
1/B 00/B 11/B 00/B 00/U 00/U 22/W
BHK 073 048/077 047/072 045/076 048/082 051/082 049/072
1/B 00/B 11/B 11/B 00/U 00/U 22/W
SHR 077 044/081 046/079 045/083 046/085 049/085 048/080
1/U 00/B 11/B 11/U 00/U 01/U 22/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
308 AM PDT TUE SEP 8 2015
.SYNOPSIS...HIGH PRESSURE ALOFT WILL BUILD NORTHWEST AND BECOME
CENTERED OVER THE MOJAVE DESERT THROUGH SATURDAY. THIS WILL RESULT
IN ABOVE NORMAL TEMPERATURES. MOIST AND UNSTABLE AIR WILL RESULT IN
THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS TODAY THROUGH THURSDAY
MAINLY IN THE AFTERNOON AND EVENING HOURS SOUTH OF INTERSTATE 40.
AFTER MAINLY DRY CONDITIONS ON FRIDAY AND SATURDAY AN AREA OF LOW
PRESSURE APPROACHING NORTHERN CALIFORNIA MAY SPARK OFF AN ISOLATED
SHOWER OR THUNDERSTORM ON SUNDAY IN THE HIGHER ELEVATIONS OF THE
MOJAVE DESERT.
&&
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT.
FOR THE THIRD MORNING IN A ROW, A FEW SHOWERS AND THUNDERSTORMS HAVE
POPPED UP IN AN AREA OF MID-LEVEL CONVERGENCE BETWEEN THE WASHED OUT
MID/UPPER LEVEL TROUGH AXIS OVER SOUTHERN NEVADA AND THE EXIT REGION
OF A 250 MB JET STREAK LOCATED OVER ARIZONA AND SOUTHEAST
CALIFORNIA. THIS ACTIVITY WAS OVER THE PLATEAU REGION OF MOHAVE
COUNTY AS WELL AS IN THE JEAN/PRIMM/GOODSPRINGS AREA. THIS SHOULD
DIMINISH IN THE NEXT FEW HOURS.
HIGH PRESSURE ALOFT LOCATED NEAR EL PASO WILL BEGIN TO EXPAND
NORTHWEST TOWARD OUR AREA TODAY. THIS WILL RESULT IN ABOVE NORMAL
TEMPERATURES WITH READINGS JUMPING UP ANOTHER DEGREE OR TWO TODAY
FROM WHAT WAS OBSERVED ON LABOR DAY. THE EAST TO SOUTHEAST FLOW IN
THE MID-LEVELS AROUND THE HIGH WILL HELP TO SLOSH MOISTURE BACK TO
THE WEST TODAY. THE HRRR, ARW, NMM, WRF, GFS AND ECMWF ALL SHOW
SIMILAR TRENDS WITH THIS THOUGH VARY WIDELY WITH QPF DEVELOPMENT.
PWATS ACROSS THE MOJAVE DESERT WILL MAINLY BE BETWEEN 0.75 INCH AND
1.00 INCH. HOWEVER, A WARM LAYER ALOFT WILL KEEP MOST OF THE AREA
CAPPED AND THUS STABLE WITH THE RESULT JUST BEING CUMULUS. ALONG AND
SOUTH OF I-40 THE CAP MAY BE ABLE TO BREAK AND ALLOW FOR SHOWERS AND
THUNDERSTORMS TO GET GOING ESPECIALLY ONCE THE CONVECTIVE
TEMPERATURE OF 104 IS REACHED. THE 700 MB FLOW TODAY IS VARIABLE
ACROSS THE AREA SO STORMS WILL BE SLOWER MOVING COMPARED TO RECENT
DAYS. ONE AREA TO WATCH WILL BE IN SOUTHERN CLARK AND NORTHEAST SAN
BERNARDINO COUNTY WHERE THE STEERING FLOW IS WESTERLY AND WE MAY SEE
ACTIVITY MAKE A RUN TOWARD THE COLORADO RIVER VALLEY. THE HRRR AND
WRF ARE BOTH QUITE ACTIVE IN THIS AREA THIS AFTERNOON AS WELL AS IN
THE MORONGO BASIN. AS A RESULT, I INCREASED POPS ACROSS THE SOUTHERN
TIER OF THE AREA TODAY. THE MAIN THREATS WILL BE FLASH FLOODING WITH
ANY STRONGER OR SLOWER MOVING STORMS AS WELL AS GUSTY AND ERRATIC
WINDS AND BLOWING DUST.
THE ROUGH FIRE NEAR HUME LAKE, CA GREW IN SIZE YESTERDAY AND
VISIBILITY IN BISHOP WAS ALREADY BACK DOWN TO 6 MILES. THE WINDS
ALOFT ARE WEAKER IN THIS AREA BUT IF THE FIRE CRANKS UP AGAIN TODAY
WITH THE HEATING OF THE DAY, WE MAY AGAIN SEE EXTENSIVE SMOKE AND
HAZE INTO NORTHERN INYO COUNTY. THIS MAY STAY LOFTED DURING THE DAY
AS SURFACE WINDS PICK UP IN THE AFTERNOON BUT AS WINDS DROP OFF AT
NIGHT, THE SMOKE SHOULD SETTLE BACK DOWN AND DROP VISIBILITY ONCE
AGAIN.
THE AFOREMENTIONED HIGH IS SLATED TO BUILD NORTHWEST INTO THE MOJAVE
DESERT AND BECOME CENTERED OVERHEAD BY THURSDAY. THIS WILL TRAP
WHATEVER MOISTURE IS IN PLACE UNDERNEATH. FOR AREAS NORTH OF I-40,
WE SHOULD REMAIN CAPPED AND AT BEST SEE A FEW CUMULUS POP UP.
HOWEVER, ACROSS THE SOUTHERN TIER OF THE AREA, THE CAP WILL NOT BE
AS STRONG, AND SHOWERS AND THUNDERSTORMS WILL HAVE BETTER CHANCE TO
DEVELOP FROM THE MORONGO BASIN EAST TO WIKIEUP AND PERHAPS AS FAR
NORTH AS LUDLOW, THE MOJAVE NATIONAL PRESERVE, SEARCHLIGHT AND
KINGMAN. PWATS ARE SHOWN TO INCREASE TO NEAR 1.50 INCH BY WEDNESDAY
AND THURSDAY NEAR VIDAL JUNCTION AND LAKE HAVASU AS ADDITIONAL
MOISTURE GETS PUSHED NORTH FROM WHAT MAY BE A SURGE TRIGGERED BY
PACIFIC HURRICANE LINDA. THIS WILL INCREASE THE FLASH FLOOD THREAT
WITH STORMS AS THEY WILL HAVE A GREATER UNLOAD FACTOR. TEMPS WILL
TREND UP FURTHER IN AREAS FREE OF STORMS, HOWEVER, WHERE CLOUDS ARE
GREATER AND STORMS ARE AROUND TEMPS WILL ACTUALLY DROP A FEW
DEGREES. SMOKE ISSUES IN INYO COUNTY FROM THE ROUGH FIRE WILL NOT GO
AWAY EITHER AS THE WINDS ALOFT REMAIN WEAK AND MAY FAVOR MORE OF A
WESTERLY DIRECTION AGAIN BY THURSDAY.
.LONG TERM...FRIDAY THROUGH TUESDAY.
THE OVERALL PATTERN IS LOOKING SOMEWHAT INTERESTING THIS WEEKEND
INTO EARLY NEXT WEEK. FRIDAY STARTS OFF WITH A STRONG RIDGE CENTERED
ALMOST DIRECTLY OVER THE FORECAST AREA WHICH WILL PROVIDE HIGH TEMPS
OF 105-110 DEGREES OVER MUCH OF THE MOJAVE DESERT REGION.
MEANWHILE...REMNANT MOISTURE FROM LINDA IS FORECAST TO BE PULLED UP
ALONG THE CALIFORNIA COAST ON THE WEST SIDE OF THE RIDGE. THE LATEST
GFS AND ECMWF SOLUTIONS ARE IN GOOD AGREEMENT WITH NUDGING THE RIDGE
TO THE SOUTHEAST OVER ARIZONA SATURDAY INTO SUNDAY BY A WEAK LOW
PRESSURE SYSTEM MOVING INTO THE NORTHERN/CENTRAL CALIFORNIA COAST.
THIS LOW ALSO DIRECTS MOISTURE INLAND ACROSS SOUTHERN CALIFORNIA AND
THE MOJAVE DESERT REGION SUNDAY INTO MONDAY. SLIGHT CHANCE POPS
WHERE INTRODUCED TO THE HIGHER TERRAIN SUNDAY AS MOISTURE BEGINS TO
MOVE INTO THE FORECAST AREA.
THE LOW IS FORECAST TO CLOSE OFF AND CIRCULATE ALONG THE CENTRAL
CALIFORNIA COAST MONDAY WHICH WOULD LEAD TO DIFFLUENT FLOW COMBINING
WITH MODERATE MOISTURE AND INSTABILITY OVER SOUTHERN NEVADA AND
NORTHWEST ARIZONA FOR AT LEAST A SLIGHT CHANCE OF THUNDERSTORMS BY
MONDAY AFTERNOON. TEMPERATURES WILL ALSO TREND DOWNWARD SUNDAY
ONWARD WITH MORE CLOUD COVER AND THE INFLUENCE OF THE COASTAL LOW.
THE GFS AND ECMWF SOLUTIONS DIVERGE WITH RESPECT TO WHAT HAPPENS
WITH THE COASTAL LOW AFTER MONDAY AND CONFIDENCE IS LOW IN ANY
DETAILS AFTER THAT.
&&
.AVIATION...FOR MCCARRAN...WINDS WILL AGAIN FAVOR TYPICAL DIURNAL
TRENDS THROUGH TONIGHT. BETWEEN 15Z TODAY AND 00Z WEDNESDAY WINDS
WILL FAVOR AN EASTERLY COMPONENT INITIALLY FROM THE NORTHEAST THEN
MORE FROM THE SOUTHEAST AT 4-8 KTS WHICH MAY CAUSE CONFIGURATION
ISSUES. BY 04Z WEDNESDAY WINDS SHOULD MORE FIRMLY STAY OUT OF THE
SOUTH. FEW-SCT CLOUDS AOA 10K FEET.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...WINDS WILL MAINLY FAVOR TYPICAL DIURNAL DIRECTIONS
THROUGH TONIGHT. ISOLATED SHRA/TSRA ARE POSSIBLE TODAY MAINLY AFTER
18Z ALONG AND SOUTH OF A LINE FROM ROUGHLY KNXP-KIFP-KIGM. GUSTY AND
ERRATIC WINDS ARE POSSIBLE IN AND NEAR ANY SHRA/TSRA. SCT-BKN CLOUDS
AOA 7K-12K FEET AS WELL ALONG AND SOUTH OF A LINE FROM KDAG-KHND-
KIGM. AREAS OF FU AND HZ ARE POSSIBLE IN AROUND KBIH REDUCING VSBY
AND CREATING LOCAL MOUNTAIN OBSCURATIONS.
&&
.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 BUFFALO NY
1000 AM EDT TUE SEP 8 2015
.SYNOPSIS...
HIGH PRESSURE OVER THE MID ATLANTIC COAST WILL CONTINUE TO BRING
MIDSUMMERLIKE CONDITIONS TO THE REGION THROUGH THE FIRST HALF OF
WEDNESDAY...BEFORE A COLD FRONT CROSSES OUR REGION BETWEEN LATER
WEDNESDAY AND WEDNESDAY NIGHT. THIS FRONT WILL BE ACCOMPANIED BY
NUMEROUS SHOWERS AND THUNDERSTORMS AS IT PASSES THROUGH...AND WILL
BE FOLLOWED BY PROGRESSIVELY COOLER WEATHER DURING THE REMAINDER
OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
DURING THE COURSE OF TODAY...THE WEAK COLD FRONT WILL BRIEFLY STALL
OUT ALONG OR SLIGHTLY NORTH OF OUR NORTHERN PERIPHERY THIS
MORNING... BEFORE LIFTING BACK NORTH THIS AFTERNOON AS A WARM FRONT
IN RESPONSE TO THE DEVELOPMENT OF BROAD LOW PRESSURE OVER THE UPPER
GREAT LAKES. ALONG AND NEAR THIS BOUNDARY...THERE WILL BE A
CONTINUED RISK OF SHOWERS AND THUNDERSTORMS THROUGH THE DAY...WITH
THIS RISK LYING ROUGHLY FROM THE NYS THRUWAY CORRIDOR NORTHWARD
THROUGH LATE THIS MORNING...THEN DIMINISHING FROM SOUTHWEST TO
NORTHEAST LATE THIS MORNING AND THIS AFTERNOON AS THE FRONT BEGINS
LIFTING BACK NORTH.
IN ADDITION TO ANY FRONTAL CONVECTION...THE COMBINATION OF DIURNAL
HEATING OF OUR VERY WARM AND HUMID AIRMASS AND REDEVELOPING LAKE
BREEZE BOUNDARIES MAY ALSO LEAD TO THE DEVELOPMENT OF A SECOND
REGION OF ISOLATED TO SCATTERED CONVECTION ACROSS AREAS SOUTH OF
LAKE ONTARIO THIS AFTERNOON...WITH THIS PRIMARILY FOCUSED FROM
INTERIOR PORTIONS OF THE SOUTHERN TIER AND GENESEE VALLEY EASTWARD
ACROSS THE FINGER LAKES.
WITH ALL OF THE ABOVE IN MIND...HAVE CONTINUED TO DEPICT A GENERAL
SOUTHWEST-NORTHEAST GRADIENT IN PRECIPITATION PROBABILITIES FOR
TODAY...WITH THESE RANGING FROM HIGH CHANCE TO LOW LIKELY FROM
LAKE ONTARIO EASTWARD ACROSS THE SAINT LAWRENCE VALLEY AND NORTH
COUNTRY...TO BELOW SLIGHT CHANCE IN AN EXPECTED REGION OF LAKE
SHADOWING IMMEDIATELY EAST OF LAKE ERIE.
OUTSIDE OF THE AFOREMENTIONED CONVECTION...DRY WEATHER AND
MIDSUMMERLIKE WARMTH AND HUMIDITY SHOULD AGAIN PREVAIL ACROSS OUR
REGION TODAY. SURFACE DEWPOINTS WILL RANGE FROM THE LOWER 60S
ACROSS INTERIOR PORTIONS OF THE SOUTHERN TIER TO NEAR 70 ALONG
THE STALLED/RETREATING FRONTAL BOUNDARY...WHILE 850 MB TEMPS OF
+16C TO +19C WILL SUPPORT HIGH TEMPERATURES RANGING FROM THE LOWER
80S ACROSS THE NORTH COUNTRY TO THE MID AND UPPER 80S ACROSS MOST
OF THE REST OF THE REGION...ALONG WITH SOME 90 DEGREE READINGS
ACROSS THE NORMAL WARM SPOTS OF THE GENESEE VALLEY/FINGER LAKES.
TONIGHT...THE WARM FRONT WILL FINISH LIFTING OFF TO OUR NORTH EARLY
IN THE EVENING. WITH THE DEPARTURE OF THIS FEATURE AND THE LOSS
OF DAYTIME HEATING...ANY LINGERING CONVECTION ACROSS THE FINGER LAKES
AND NORTH COUNTRY WILL COME TO AN END THIS EVENING...LEAVING BEHIND
LARGELY DRY WEATHER FOR THE BALANCE OF THE NIGHTTIME HOURS AS OUR
REGION WILL BE FIRMLY ENTRENCHED WITHIN THE WARM SECTOR OF LOW
PRESSURE LIFTING BY WELL TO OUR NORTHWEST. THUS...WE CAN EXPECT YET
ANOTHER UNSEASONABLY WARM NIGHT ACROSS OUR REGION...WITH OVERNIGHT
LOWS AGAIN RANGING FROM THE MID 60S ACROSS INTERIOR PORTIONS OF THE
SOUTHERN TIER TO THE LOWER 70S ACROSS THE LAKE PLAINS...OR LEVELS
THAT WILL BE NOT THAT FAR OFF FROM NORMAL HIGH TEMPERATURES FOR
EARLY SEPTEMBER.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
TEMPERATURES WILL RETURN TO NEAR NORMAL LEVELS ACROSS THE LOWER
GREAT LAKES DURING THIS PERIOD...AS THE UPPER LEVEL FLOW ACROSS
NORTH AMERICA WILL FEATURE AN AMPLIFYING TROUGH OVER THE EASTERN
HALF OF THE CONTINENT. THIS WILL BE SIGNIFICANT CHANGE FROM THE
FIRST WEEK OF SEPTEMBER WHEN A PERSISTENT SUB-TROPICAL RIDGE
DOMINATED THE EASTERN HALF OF THE COUNTRY. WHILE THE RIDGE WAS NOT
OVERLY IMPRESSIVE `ON PAPER`...ITS STAYING POWER FOR THIS TIME OF
YEAR ALLOWED FOR ANOMALOUSLY WARM AIR AND PLENTY OF GULF HUMIDITY
TO CREATE THE WARMEST STRETCH OF WEATHER OUR REGION EXPERIENCED
ALL SUMMER. WITH THE PASSING OF THE LAST SUMMER HOLIDAY...MOTHER
NATURE WILL ALSO TURN THE PAGE...ALBEIT IT SLOWLY.
AS IS SO OFTEN IS THE CASE...A STRONG LATITUDINAL H25 JET
CROSSING THE NORTHERN PACIFIC WILL PLOW ACROSS THE CANADIAN
ROCKIES AND ESTABLISH A BROAD DOWNSTREAM TROUGH OVER THE EASTERN
HALF OF THE CONTINENT. THIS TROUGH WILL FLATTEN THE PERTINACIOUS
SUB TROPICAL RIDGE...AND IN TIME WILL DIRECT PROGRESSIVELY COOLER
CANADIAN AIR SOUTHWARDS ACROSS THE LOWER 48. THIS COOLING WILL
INITIALLY ONLY TAKE OUR TEMPERATURES BACK TOWARDS NORMAL...BUT AS
WE HEAD IN TO THE WEEKEND...WE COULD EXPERIENCE A DAY OR TWO OF
FALL LIKE CONDITIONS.
AN INVERTED SFC TROUGH EXTENDING FROM THE UPPER GREAT LAKES TO
THE CENTRAL PLAINS LATE TUESDAY NIGHT WILL GRADUALLY EVOLVE INTO A
LEGITIMATE...ALBEIT WAVY...COLD FRONT ON WEDNESDAY AS IT WILL PUSH
SOUTHEAST ACROSS THE LOWER GREAT LAKES. THE OVERALL SYNOPTIC
FORCING WITH THE SLOW MOVING FRONTAL BOUNDARY IS NOT BEING
ADVERTISED AS BEING ALL THAT IMPRESSIVE...BUT IT WILL BE ENOUGH IN
COMBINATION WITH THE MID SUMMER LIKE THERMODYNAMIC ENVIRONMENT TO
PRODUCE INCREASINGLY NUMEROUS SHOWERS AND POTENTIALLY STRONG
THUNDERSTORMS.
ADDRESSING THE FORMER FIRST...AS EARLIER MENTIONED THE FRONTAL
BOUNDARY WILL STILL BE TAKING SHAPE DURING THE DAY WEDNESDAY AS IT
WILL BE PUSHING INTO OUR FORECAST AREA. TRUE FRONTOGENETIC FORCING
FROM THE FRONT WILL THUS BE GENERALLY WEAK...ALTHOUGH HGT FALLS
AND A 120KT H25 JET OVER NORTHERN QUEBEC WILL ADD SOME LARGE SCALE
SYNOPTIC LIFT BY PLACING OUR FORECAST AREA UNDER RR QUAD OF THE
JET ENTRANCE REGION. THERMODYNAMICALLY...OUR WARM HUMID AIRMASS
WILL ALREADY BE UNSTABLE. SBCAPES WILL ALREADY BE IN THE HUNDREDS
AS WE OPEN THE DAY...AND DIMINISHING MORNING SUNSHINE WILL ONLY
ADD TO THIS INSTABILITY...PARTICULARLY OVER PARTS OF THE SRN TIER
AND FINGER LAKES REGIONS WHERE MUCAPES COULD APPROACH 2000 J/KG.
MEANWHILE A SWATH OF TROPICAL MOISTURE TO THE TUNE OF 2 INCH PWAT
VALUES WILL STREAM ACROSS OUR REGION ALONG AND AHEAD OF THE SFC
BOUNDARY...SO THIS IN COMBINATION WITH THE SYNOPTIC FORCING AND
INSTABILITY COULD RESULT IN TORRENTIAL DOWNPOURS WITH SOME OF THE
CONVECTION. FORTUNATELY...THE REGION IS PARCHED FROM A GENERAL
LACK OF RAINFALL FROM THE PAST MONTH OR SO...AND GUIDANCE IS
SUGGESTING THAT CORFIDI VECTORS WILL LENGTHEN AS THE FRONT
APPROACHES. THIS WILL LESSEN THE RISK FOR WIDESPREAD HYDRO RELATED
PROBLEMS...BUT LOCAL ISSUES WILL STILL HAVE TO BE ADDRESSED GIVEN
THE SUB TROPICAL ENVIRONMENT. THE MENTION OF TORRENTIAL DOWNPOURS
HAS ALREADY BEEN ADDED TO THE HWO PRODUCT AND TO THE GRIDDED DATA
BASE...SO WILL CONTINUE.
ALONG WITH THE THREAT FOR LOCALLY HEAVY CONVECTIVE RAINS...THERE
WILL BE AN ISOLATED RISK FOR STRONG THUNDERSTORMS. THIS POTENTIAL
WILL BE ATTENUATED BY UNIMPRESSIVE MID LEVEL LAPSE RATES UNDER 6
DEG C/KM...BUT GIVEN BULK SHEAR VALUES OF 35 TO 40 KNOTS AND THE
UNCERTAINTY AS TO HOW MUCH SUNSHINE PARTS OF THE REGION RECEIVE...
WE WILL CONTINUE TO HIGHLIGHT THE CHANCE FOR GUSTY CONVECTIVE
WINDS.
CONSIDERING ALL OF THE ABOVE...WEDNESDAY SHOULD START OFF DRY
ACROSS OUR FORECAST AREA...BUT AS THE FRONT NEARS DURING THE
MIDDAY...CONVECTION WILL BEGIN TO BREAK OUT. THIS MAY BE HASTENED
ACROSS PARTS OF THE SRN TIER AND FINGER LAKES REGION WHERE A LAKE
BREEZE BOUNDARY COULD FOCUS AN INITIAL ROUND OF STORMS...THEN AS
THE FRONT SLOWLY CROSSES THE LOWER GREAT LAKES IN THE AFTERNOON
AND EVENING...THE GENERAL CONDITIONS WILL FURTHER DETERIORATE.
WILL MAINTAIN LIKELY POPS REGIONWIDE FOR THE LATE AFTERNOON...
BUT THE VAST MAJORITY OF THE DAY SHOULD BE RAIN FREE. OTHERWISE
WEDNESDAY WILL BE WARM AND HUMID WITH MAX TEMPS RANGING FROM THE
LOWER 80S OVER THE FAR WEST TO THE MID AND POSSIBLY UPPER 80S
ACROSS PARTS OF THE FINGER LAKES.
DURING THE COURSE OF WEDNESDAY NIGHT...THE FRONTAL BOUNDARY WILL
LAZILY CROSS OUR FORECAST AREA AS UPSTREAM SFC WAVES WILL RETARD
ITS FORWARD PROGRESS. THIS IS THE TIME PERIOD WHERE THE AXIS OF
THE DEEPEST MOISTURE WILL CROSS OUR FORECAST AREA. WHILE DIURNALLY
ENHANCED INSTABILITY WILL BE WANING...THE PASSAGE OF ANY WAVES
ALONG THE FRONTAL BOUNDARY COULD SYNOPTICALLY ENHANCE ANY SHOWERS
INTO A 2 TO THREE HOUR PERIOD OF STEADIER RAIN. THIS POTENTIAL
WILL BE GREATEST OVER THE SRN TIER AND FINGER LAKES REGION.
AGAIN...WE WILL BE FORTUNATE IN THAT WE HAVE VERY DRY ANTECEDENT
CONDITIONS.
ON THURSDAY...WEAK HIGH PRESSURE OVER LOWER MICHIGAN WILL
GRADUALLY BUILD ACROSS OUR FORECAST AREA WHILE THE FLEXUOUS
FRONTAL BOUNDARY WILL MAKE ITS WAY TO THE EAST COAST. SHOWERS...
THAT WILL BE MOST LIKELY EAST OF LINE FROM ROCHESTER TO
JAMESTOWN...WILL TAPER OFF FROM WEST TO EAST IN THE PROCESS.
SUNSHINE SHOULD RETURN IN FORCE TO THE NIAGARA FRONTIER AND PARTS
OF THE SRN TIER BY THE AFTERNOON...BUT THE IMPROVEMENT WILL TAKE
LONGER FURTHER EAST. IT WILL START TO FEEL MUCH MORE COMFORTABLE
AS WELL...AS THE FRESH AIRMASS WILL START TO SETTLE OVER THE
REGION WITH DEW POINTS OVER THE WESTERN COUNTIES STEADIER FALLING
THROUGH THE 50S. AFTER NEARLY TWO WEEKS OF AFTERNOON TEMPERATURES
IN THE 80S...MAX TEMPS ON THURSDAY SHOULD FINALLY RETURN TO THE
70S.
THE GRADUAL CLEARING PROCESS WILL CONTINUE THURSDAY NIGHT AS THE
LEADING EDGE OF HIGH PRESSURE WILL WORK ACROSS OUR FORECAST AREA.
ANY LEFTOVER SHOWERS OVER EASTERN SECTIONS SHOULD END DURING THE
EVENING WITH MUCH MORE COMFORTABLE SLEEPING CONDITIONS GAINING A
FOOTHOLD OVER THE ENTIRE FORECAST AREA. OVERNIGHT LOWS WILL
GENERALLY BE IN THE 50S...WITH THE RADIATIONAL COOLING PROBABLY
LEADING TO SOME VALLEY FOG ACROSS PARTS OF THE SRN TIER AND FINGER
LAKES REGIONS.
WHILE PLEASANT WEATHER IS EXPECTED ACROSS OUR REGION ON FRIDAY...
A MID LEVEL DISTURBANCE DIGGING INTO THE GREAT LAKES LONGWAVE
TROUGH WILL ENCOURAGE SOME `BAGGINESS` IN THE SFC PRESSURE FIELD
ACROSS THE UPPER OHIO VALLEY. THIS WILL BE THE BEGINNINGS OF WHAT
COULD POTENTIALLY BE A CLOSED LOW FOR OUR REGION DURING THE
UPCOMING WEEKEND. MORE ON THIS LOW CONFIDENCE EVENT IN THE LONG
TERM SECTION BELOW. GENERALLY PARTLY SUNNY SKIES CAN BE EXPECTED
ON FRIDAY WITH AFTERNOON TEMPERATURES IN THE 70S BEING ACCOMPANIED
BY COMFORTABLY LOW HUMIDITY LEVELS.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
ONCE AGAIN...THE MEDIUM RANGE GUIDANCE PACKAGES ARE VASTLY
DIFFERENT IN THEIR SOLUTIONS OVER THE LOWER GREAT LAKES IN THE
DAYS 5-7 PERIOD. BOTH THE GFS AND ECMWF OPERATIONAL MODELS ARE
STUBBORNLY HOLDING ONTO THE SAME SCENARIOS THAT THEY HAVE BEEN
PREACHING FOR THE PAST COUPLE DAYS... WITH THE LATTER DEPICTING
THE DEVELOPMENT OF A STACKED STORM SYSTEM OVER SOUTHERN ONTARIO
AND THE LOWER GREAT LAKES. NEEDLESS TO SAY...THIS WOULD BE A VERY
UNSETTLED SOLUTION FOR OUR FORECAST AREA WITH FAIRLY WIDESPREAD
FREQUENT SHOWERS.
BECAUSE OF THE DISPARITY WITHIN THE GUIDANCE PACKAGES...HAVE NO
CHOICE BUT TO KEEP THE LOW/SLGT CHC BROADBRUSH POPS THAT ARE IN
CONTINUITY IN PLACE THROUGH AT LEAST THE WEEKEND.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
A WEAK COLD FRONT WILL BRIEFLY STALL OUT ALONG OR SLIGHTLY NORTH
OF OUR NORTHERN PERIPHERY THIS MORNING...BEFORE LIFTING BACK
NORTH THIS AFTERNOON AS A WARM FRONT IN RESPONSE TO THE DEVELOPMENT
OF BROAD LOW PRESSURE OVER THE UPPER GREAT LAKES. THERE WILL BE
A CONTINUED RISK OF SHOWERS/THUNDERSTORMS AND ATTENDANT RESTRICTIONS
ALONG AND NEAR THIS BOUNDARY THROUGH THE DAY...AND ALSO ALONG AND
INLAND FROM A DEVELOPING LAKE ERIE LAKE BREEZE BOUNDARY DURING THE
AFTERNOON. OUTSIDE OF ANY SUCH CONVECTION AND ANY EARLY MORNING
MVFR SOUTHERN TIER VALLEY FOG... VFR CONDITIONS SHOULD OTHERWISE
PREVAIL.
TONIGHT...THE FRONTAL BOUNDARY WILL FINISH LIFTING OFF TO OUR NORTH
EARLY IN THE EVENING. WITH THE DEPARTURE OF THIS FEATURE AND THE LOSS
OF DAYTIME HEATING...ANY LINGERING CONVECTION/ATTENDANT RESTRICTIONS
ACROSS THE FINGER LAKES AND NORTH COUNTRY WILL COME TO AN END THIS
EVENING...LEAVING BEHIND LARGELY DRY/VFR CONDITIONS FOR THE BALANCE
OF THE NIGHTTIME HOURS.
OUTLOOK...
WEDNESDAY...MAINLY VFR INITIALLY...THEN SHOWERS AND THUNDERSTORMS
WITH ATTENDANT REDUCTIONS TO IFR/MVFR BECOMING LIKELY FOR WEDNESDAY
AFTERNOON AND EVENING.
THURSDAY...SCATTERED TO NUMEROUS SHOWERS TAPERING OFF WITH CONDITIONS
IMPROVING TO VFR.
FRIDAY...MAINLY VFR...EXCEPT IN POSSIBLE MORNING SOUTHERN TIER
VALLEY FOG.
SATURDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
HIGH PRESSURE CENTERED OVER THE MID ATLANTIC COASTLINE WILL SLOWLY
DRIFT OFFSHORE THROUGH MIDWEEK. A STALLED OUT COLD FRONT DRAPED FROM
THE SAINT LAWRENCE VALLEY SOUTHWESTWARD ACROSS LAKE ONTARIO WILL LIFT
BACK NORTH OF THE REGION AS A WARM FRONT THIS AFTERNOON AND EVENING
IN RESPONSE TO DEVELOPING LOW PRESSURE ACROSS THE UPPER GREAT LAKES...
THEN THIS LATTER FEATURE WILL SLOWLY EASE ITS TRAILING COLD FRONT
ACROSS THE AREA WEDNESDAY AFTERNOON AND NIGHT.
THE INITIAL FRONTAL BOUNDARY WILL CONTINUE TO TRIGGER SCATTERED
SHOWERS AND THUNDERSTORMS AS IT LINGERS NEAR THE LOWER GREAT LAKES
THIS MORNING...WITH THESE THEN GRADUALLY DIMINISHING FROM SOUTHWEST
TO NORTHEAST THIS AFTERNOON AND EVENING AS THE BOUNDARY LIFTS AWAY
FROM OUR REGION. FOLLOWING ITS DEPARTURE...GENERALLY DRY CONDITIONS
ARE EXPECTED FOR THE BALANCE OF TONIGHT...BEFORE THE TRAILING COLD
FRONT BRINGS MORE NUMEROUS SHOWERS AND THUNDERSTORMS AS IT PASSES
THROUGH THE REGION WEDNESDAY AFTERNOON AND NIGHT.
WHILE ANY OF THE SHOWERS/STORMS COULD PRODUCE LOCALLY HIGHER WINDS AND
WAVES OVER THE NEXT COUPLE OF DAYS...IN GENERAL LIGHT TO MODEST WINDS
WILL PREVAIL ACROSS THE LOWER LAKES REGION THROUGH WEDNESDAY NIGHT...
ALONG WITH WAVES OF UNDER 3 FEET.
FOLLOWING THE PASSAGE OF THE FRONT...HIGH PRESSURE IS EXPECTED TO
BUILD ACROSS THE REGION THURSDAY AND FRIDAY WHILE BRINGING A RETURN
TO MORE SETTLED CONDITIONS...ALONG WITH CONTINUED LIGHT TO MODEST
WINDS AND MINIMAL WAVES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JJR
NEAR TERM...CHURCH/JJR
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...JJR
MARINE...JJR
AREA FORECAST DISCUSSION
NWS BUFFALO NY
732 AM EDT TUE SEP 8 2015
.SYNOPSIS...
HIGH PRESSURE OVER THE MID ATLANTIC COAST WILL CONTINUE TO BRING
MIDSUMMERLIKE CONDITIONS TO THE REGION THROUGH THE FIRST HALF OF
WEDNESDAY...BEFORE A COLD FRONT CROSSES OUR REGION BETWEEN LATER
WEDNESDAY AND WEDNESDAY NIGHT. THIS FRONT WILL BE ACCOMPANIED BY
NUMEROUS SHOWERS AND THUNDERSTORMS AS IT PASSES THROUGH...AND WILL
BE FOLLOWED BY PROGRESSIVELY COOLER WEATHER DURING THE REMAINDER
OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1130Z...REGIONAL SURFACE OBSERVATIONS SUGGEST THAT THE WEAK
COLD FRONTAL BOUNDARY EXTENDS FROM THE SAINT LAWRENCE VALLEY
ACROSS NORTHERN LAKE ONTARIO TO THE GREATER TORONTO AREA...AND
THEN ON ACROSS SOUTHWESTERN ONTARIO. ALONG AND NEAR THIS BOUNDARY...
REGIONAL RADARS DEPICT AN ELONGATED SWATH OF SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS...WITH THE MOST NUMEROUS ACTIVITY NOW
WORKING INTO THE GOLDEN HORSESHOE REGION OF ONTARIO.
DURING THE COURSE OF TODAY...THE WEAK COLD FRONT WILL BRIEFLY STALL
OUT ALONG OR SLIGHTLY NORTH OF OUR NORTHERN PERIPHERY THIS MORNING...
BEFORE LIFTING BACK NORTH THIS AFTERNOON AS A WARM FRONT IN RESPONSE
TO THE DEVELOPMENT OF BROAD LOW PRESSURE OVER THE UPPER GREAT LAKES.
ALONG AND NEAR THIS BOUNDARY...THERE WILL BE A CONTINUED RISK OF
SHOWERS AND THUNDERSTORMS THROUGH THE DAY...WITH THIS RISK LYING
ROUGHLY FROM THE NYS THRUWAY CORRIDOR NORTHWARD THROUGH LATE THIS
MORNING...THEN DIMINISHING FROM SOUTHWEST TO NORTHEAST LATE THIS
MORNING AND THIS AFTERNOON AS THE FRONT BEGINS LIFTING BACK NORTH.
IN ADDITION TO ANY FRONTAL CONVECTION...THE COMBINATION OF DIURNAL
HEATING OF OUR VERY WARM AND HUMID AIRMASS AND REDEVELOPING LAKE
BREEZE BOUNDARIES MAY ALSO LEAD TO THE DEVELOPMENT OF A SECOND
REGION OF ISOLATED TO SCATTERED CONVECTION ACROSS AREAS SOUTH OF
LAKE ONTARIO THIS AFTERNOON...WITH THIS PRIMARILY FOCUSED FROM
INTERIOR PORTIONS OF THE SOUTHERN TIER AND GENESEE VALLEY EASTWARD
ACROSS THE FINGER LAKES.
WITH ALL OF THE ABOVE IN MIND...HAVE CONTINUED TO DEPICT A GENERAL
SOUTHWEST-NORTHEAST GRADIENT IN PRECIPITATION PROBABILITIES FOR
TODAY...WITH THESE RANGING FROM HIGH CHANCE TO LOW LIKELY FROM
LAKE ONTARIO EASTWARD ACROSS THE SAINT LAWRENCE VALLEY AND NORTH
COUNTRY...TO BELOW SLIGHT CHANCE IN AN EXPECTED REGION OF LAKE
SHADOWING IMMEDIATELY EAST OF LAKE ERIE.
OUTSIDE OF THE AFOREMENTIONED CONVECTION...DRY WEATHER AND
MIDSUMMERLIKE WARMTH AND HUMIDITY SHOULD AGAIN PREVAIL ACROSS OUR
REGION TODAY. SURFACE DEWPOINTS WILL RANGE FROM THE LOWER 60S
ACROSS INTERIOR PORTIONS OF THE SOUTHERN TIER TO NEAR 70 ALONG
THE STALLED/RETREATING FRONTAL BOUNDARY...WHILE 850 MB TEMPS OF
+16C TO +19C WILL SUPPORT HIGH TEMPERATURES RANGING FROM THE LOWER
80S ACROSS THE NORTH COUNTRY TO THE MID AND UPPER 80S ACROSS MOST
OF THE REST OF THE REGION...ALONG WITH SOME 90 DEGREE READINGS
ACROSS THE NORMAL WARM SPOTS OF THE GENESEE VALLEY/FINGER LAKES.
TONIGHT...THE WARM FRONT WILL FINISH LIFTING OFF TO OUR NORTH EARLY
IN THE EVENING. WITH THE DEPARTURE OF THIS FEATURE AND THE LOSS
OF DAYTIME HEATING...ANY LINGERING CONVECTION ACROSS THE FINGER LAKES
AND NORTH COUNTRY WILL COME TO AN END THIS EVENING...LEAVING BEHIND
LARGELY DRY WEATHER FOR THE BALANCE OF THE NIGHTTIME HOURS AS OUR
REGION WILL BE FIRMLY ENTRENCHED WITHIN THE WARM SECTOR OF LOW
PRESSURE LIFTING BY WELL TO OUR NORTHWEST. THUS...WE CAN EXPECT YET
ANOTHER UNSEASONABLY WARM NIGHT ACROSS OUR REGION...WITH OVERNIGHT
LOWS AGAIN RANGING FROM THE MID 60S ACROSS INTERIOR PORTIONS OF THE
SOUTHERN TIER TO THE LOWER 70S ACROSS THE LAKE PLAINS...OR LEVELS
THAT WILL BE NOT THAT FAR OFF FROM NORMAL HIGH TEMPERATURES FOR
EARLY SEPTEMBER.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
TEMPERATURES WILL RETURN TO NEAR NORMAL LEVELS ACROSS THE LOWER
GREAT LAKES DURING THIS PERIOD...AS THE UPPER LEVEL FLOW ACROSS
NORTH AMERICA WILL FEATURE AN AMPLIFYING TROUGH OVER THE EASTERN
HALF OF THE CONTINENT. THIS WILL BE SIGNIFICANT CHANGE FROM THE
FIRST WEEK OF SEPTEMBER WHEN A PERSISTENT SUB-TROPICAL RIDGE
DOMINATED THE EASTERN HALF OF THE COUNTRY. WHILE THE RIDGE WAS NOT
OVERLY IMPRESSIVE `ON PAPER`...ITS STAYING POWER FOR THIS TIME OF
YEAR ALLOWED FOR ANOMALOUSLY WARM AIR AND PLENTY OF GULF HUMIDITY
TO CREATE THE WARMEST STRETCH OF WEATHER OUR REGION EXPERIENCED
ALL SUMMER. WITH THE PASSING OF THE LAST SUMMER HOLIDAY...MOTHER
NATURE WILL ALSO TURN THE PAGE...ALBEIT IT SLOWLY.
AS IS SO OFTEN IS THE CASE...A STRONG LATITUDINAL H25 JET
CROSSING THE NORTHERN PACIFIC WILL PLOW ACROSS THE CANADIAN
ROCKIES AND ESTABLISH A BROAD DOWNSTREAM TROUGH OVER THE EASTERN
HALF OF THE CONTINENT. THIS TROUGH WILL FLATTEN THE PERTINACIOUS
SUB TROPICAL RIDGE...AND IN TIME WILL DIRECT PROGRESSIVELY COOLER
CANADIAN AIR SOUTHWARDS ACROSS THE LOWER 48. THIS COOLING WILL
INITIALLY ONLY TAKE OUR TEMPERATURES BACK TOWARDS NORMAL...BUT AS
WE HEAD IN TO THE WEEKEND...WE COULD EXPERIENCE A DAY OR TWO OF
FALL LIKE CONDITIONS.
AN INVERTED SFC TROUGH EXTENDING FROM THE UPPER GREAT LAKES TO
THE CENTRAL PLAINS LATE TUESDAY NIGHT WILL GRADUALLY EVOLVE INTO A
LEGITIMATE...ALBEIT WAVY...COLD FRONT ON WEDNESDAY AS IT WILL PUSH
SOUTHEAST ACROSS THE LOWER GREAT LAKES. THE OVERALL SYNOPTIC
FORCING WITH THE SLOW MOVING FRONTAL BOUNDARY IS NOT BEING
ADVERTISED AS BEING ALL THAT IMPRESSIVE...BUT IT WILL BE ENOUGH IN
COMBINATION WITH THE MID SUMMER LIKE THERMODYNAMIC ENVIRONMENT TO
PRODUCE INCREASINGLY NUMEROUS SHOWERS AND POTENTIALLY STRONG
THUNDERSTORMS.
ADDRESSING THE FORMER FIRST...AS EARLIER MENTIONED THE FRONTAL
BOUNDARY WILL STILL BE TAKING SHAPE DURING THE DAY WEDNESDAY AS IT
WILL BE PUSHING INTO OUR FORECAST AREA. TRUE FRONTOGENETIC FORCING
FROM THE FRONT WILL THUS BE GENERALLY WEAK...ALTHOUGH HGT FALLS
AND A 120KT H25 JET OVER NORTHERN QUEBEC WILL ADD SOME LARGE SCALE
SYNOPTIC LIFT BY PLACING OUR FORECAST AREA UNDER RR QUAD OF THE
JET ENTRANCE REGION. THERMODYNAMICALLY...OUR WARM HUMID AIRMASS
WILL ALREADY BE UNSTABLE. SBCAPES WILL ALREADY BE IN THE HUNDREDS
AS WE OPEN THE DAY...AND DIMINISHING MORNING SUNSHINE WILL ONLY
ADD TO THIS INSTABILITY...PARTICULARLY OVER PARTS OF THE SRN TIER
AND FINGER LAKES REGIONS WHERE MUCAPES COULD APPROACH 2000 J/KG.
MEANWHILE A SWATH OF TROPICAL MOISTURE TO THE TUNE OF 2 INCH PWAT
VALUES WILL STREAM ACROSS OUR REGION ALONG AND AHEAD OF THE SFC
BOUNDARY...SO THIS IN COMBINATION WITH THE SYNOPTIC FORCING AND
INSTABILITY COULD RESULT IN TORRENTIAL DOWNPOURS WITH SOME OF THE
CONVECTION. FORTUNATELY...THE REGION IS PARCHED FROM A GENERAL
LACK OF RAINFALL FROM THE PAST MONTH OR SO...AND GUIDANCE IS
SUGGESTING THAT CORFIDI VECTORS WILL LENGTHEN AS THE FRONT
APPROACHES. THIS WILL LESSEN THE RISK FOR WIDESPREAD HYDRO RELATED
PROBLEMS...BUT LOCAL ISSUES WILL STILL HAVE TO BE ADDRESSED GIVEN
THE SUB TROPICAL ENVIRONMENT. THE MENTION OF TORRENTIAL DOWNPOURS
HAS ALREADY BEEN ADDED TO THE HWO PRODUCT AND TO THE GRIDDED DATA
BASE...SO WILL CONTINUE.
ALONG WITH THE THREAT FOR LOCALLY HEAVY CONVECTIVE RAINS...THERE
WILL BE AN ISOLATED RISK FOR STRONG THUNDERSTORMS. THIS POTENTIAL
WILL BE ATTENUATED BY UNIMPRESSIVE MID LEVEL LAPSE RATES UNDER 6
DEG C/KM...BUT GIVEN BULK SHEAR VALUES OF 35 TO 40 KNOTS AND THE
UNCERTAINTY AS TO HOW MUCH SUNSHINE PARTS OF THE REGION RECEIVE...
WE WILL CONTINUE TO HIGHLIGHT THE CHANCE FOR GUSTY CONVECTIVE
WINDS.
CONSIDERING ALL OF THE ABOVE...WEDNESDAY SHOULD START OFF DRY
ACROSS OUR FORECAST AREA...BUT AS THE FRONT NEARS DURING THE
MIDDAY...CONVECTION WILL BEGIN TO BREAK OUT. THIS MAY BE HASTENED
ACROSS PARTS OF THE SRN TIER AND FINGER LAKES REGION WHERE A LAKE
BREEZE BOUNDARY COULD FOCUS AN INITIAL ROUND OF STORMS...THEN AS
THE FRONT SLOWLY CROSSES THE LOWER GREAT LAKES IN THE AFTERNOON
AND EVENING...THE GENERAL CONDITIONS WILL FURTHER DETERIORATE.
WILL MAINTAIN LIKELY POPS REGIONWIDE FOR THE LATE AFTERNOON...
BUT THE VAST MAJORITY OF THE DAY SHOULD BE RAIN FREE. OTHERWISE
WEDNESDAY WILL BE WARM AND HUMID WITH MAX TEMPS RANGING FROM THE
LOWER 80S OVER THE FAR WEST TO THE MID AND POSSIBLY UPPER 80S
ACROSS PARTS OF THE FINGER LAKES.
DURING THE COURSE OF WEDNESDAY NIGHT...THE FRONTAL BOUNDARY WILL
LAZILY CROSS OUR FORECAST AREA AS UPSTREAM SFC WAVES WILL RETARD
ITS FORWARD PROGRESS. THIS IS THE TIME PERIOD WHERE THE AXIS OF
THE DEEPEST MOISTURE WILL CROSS OUR FORECAST AREA. WHILE DIURNALLY
ENHANCED INSTABILITY WILL BE WANING...THE PASSAGE OF ANY WAVES
ALONG THE FRONTAL BOUNDARY COULD SYNOPTICALLY ENHANCE ANY SHOWERS
INTO A 2 TO THREE HOUR PERIOD OF STEADIER RAIN. THIS POTENTIAL
WILL BE GREATEST OVER THE SRN TIER AND FINGER LAKES REGION.
AGAIN...WE WILL BE FORTUNATE IN THAT WE HAVE VERY DRY ANTECEDENT
CONDITIONS.
ON THURSDAY...WEAK HIGH PRESSURE OVER LOWER MICHIGAN WILL
GRADUALLY BUILD ACROSS OUR FORECAST AREA WHILE THE FLEXUOUS
FRONTAL BOUNDARY WILL MAKE ITS WAY TO THE EAST COAST. SHOWERS...
THAT WILL BE MOST LIKELY EAST OF LINE FROM ROCHESTER TO
JAMESTOWN...WILL TAPER OFF FROM WEST TO EAST IN THE PROCESS.
SUNSHINE SHOULD RETURN IN FORCE TO THE NIAGARA FRONTIER AND PARTS
OF THE SRN TIER BY THE AFTERNOON...BUT THE IMPROVEMENT WILL TAKE
LONGER FURTHER EAST. IT WILL START TO FEEL MUCH MORE COMFORTABLE
AS WELL...AS THE FRESH AIRMASS WILL START TO SETTLE OVER THE
REGION WITH DEW POINTS OVER THE WESTERN COUNTIES STEADIER FALLING
THROUGH THE 50S. AFTER NEARLY TWO WEEKS OF AFTERNOON TEMPERATURES
IN THE 80S...MAX TEMPS ON THURSDAY SHOULD FINALLY RETURN TO THE
70S.
THE GRADUAL CLEARING PROCESS WILL CONTINUE THURSDAY NIGHT AS THE
LEADING EDGE OF HIGH PRESSURE WILL WORK ACROSS OUR FORECAST AREA.
ANY LEFTOVER SHOWERS OVER EASTERN SECTIONS SHOULD END DURING THE
EVENING WITH MUCH MORE COMFORTABLE SLEEPING CONDITIONS GAINING A
FOOTHOLD OVER THE ENTIRE FORECAST AREA. OVERNIGHT LOWS WILL
GENERALLY BE IN THE 50S...WITH THE RADIATIONAL COOLING PROBABLY
LEADING TO SOME VALLEY FOG ACROSS PARTS OF THE SRN TIER AND FINGER
LAKES REGIONS.
WHILE PLEASANT WEATHER IS EXPECTED ACROSS OUR REGION ON FRIDAY...
A MID LEVEL DISTURBANCE DIGGING INTO THE GREAT LAKES LONGWAVE
TROUGH WILL ENCOURAGE SOME `BAGGINESS` IN THE SFC PRESSURE FIELD
ACROSS THE UPPER OHIO VALLEY. THIS WILL BE THE BEGINNINGS OF WHAT
COULD POTENTIALLY BE A CLOSED LOW FOR OUR REGION DURING THE
UPCOMING WEEKEND. MORE ON THIS LOW CONFIDENCE EVENT IN THE LONG
TERM SECTION BELOW. GENERALLY PARTLY SUNNY SKIES CAN BE EXPECTED
ON FRIDAY WITH AFTERNOON TEMPERATURES IN THE 70S BEING ACCOMPANIED
BY COMFORTABLY LOW HUMIDITY LEVELS.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
ONCE AGAIN...THE MEDIUM RANGE GUIDANCE PACKAGES ARE VASTLY
DIFFERENT IN THEIR SOLUTIONS OVER THE LOWER GREAT LAKES IN THE
DAYS 5-7 PERIOD. BOTH THE GFS AND ECMWF OPERATIONAL MODELS ARE
STUBBORNLY HOLDING ONTO THE SAME SCENARIOS THAT THEY HAVE BEEN
PREACHING FOR THE PAST COUPLE DAYS... WITH THE LATTER DEPICTING
THE DEVELOPMENT OF A STACKED STORM SYSTEM OVER SOUTHERN ONTARIO
AND THE LOWER GREAT LAKES. NEEDLESS TO SAY...THIS WOULD BE A VERY
UNSETTLED SOLUTION FOR OUR FORECAST AREA WITH FAIRLY WIDESPREAD
FREQUENT SHOWERS.
BECAUSE OF THE DISPARITY WITHIN THE GUIDANCE PACKAGES...HAVE NO
CHOICE BUT TO KEEP THE LOW/SLGT CHC BROADBRUSH POPS THAT ARE IN
CONTINUITY IN PLACE THROUGH AT LEAST THE WEEKEND.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
A WEAK COLD FRONT WILL BRIEFLY STALL OUT ALONG OR SLIGHTLY NORTH
OF OUR NORTHERN PERIPHERY THIS MORNING...BEFORE LIFTING BACK
NORTH THIS AFTERNOON AS A WARM FRONT IN RESPONSE TO THE DEVELOPMENT
OF BROAD LOW PRESSURE OVER THE UPPER GREAT LAKES. THERE WILL BE
A CONTINUED RISK OF SHOWERS/THUNDERSTORMS AND ATTENDANT RESTRICTIONS
ALONG AND NEAR THIS BOUNDARY THROUGH THE DAY...AND ALSO ALONG AND
INLAND FROM A DEVELOPING LAKE ERIE LAKE BREEZE BOUNDARY DURING THE
AFTERNOON. OUTSIDE OF ANY SUCH CONVECTION AND ANY EARLY MORNING
MVFR SOUTHERN TIER VALLEY FOG... VFR CONDITIONS SHOULD OTHERWISE
PREVAIL.
TONIGHT...THE FRONTAL BOUNDARY WILL FINISH LIFTING OFF TO OUR NORTH
EARLY IN THE EVENING. WITH THE DEPARTURE OF THIS FEATURE AND THE LOSS
OF DAYTIME HEATING...ANY LINGERING CONVECTION/ATTENDANT RESTRICTIONS
ACROSS THE FINGER LAKES AND NORTH COUNTRY WILL COME TO AN END THIS
EVENING...LEAVING BEHIND LARGELY DRY/VFR CONDITIONS FOR THE BALANCE
OF THE NIGHTTIME HOURS.
OUTLOOK...
WEDNESDAY...MAINLY VFR INITIALLY...THEN SHOWERS AND THUNDERSTORMS
WITH ATTENDANT REDUCTIONS TO IFR/MVFR BECOMING LIKELY FOR WEDNESDAY
AFTERNOON AND EVENING.
THURSDAY...SCATTERED TO NUMEROUS SHOWERS TAPERING OFF WITH CONDITIONS
IMPROVING TO VFR.
FRIDAY...MAINLY VFR...EXCEPT IN POSSIBLE MORNING SOUTHERN TIER
VALLEY FOG.
SATURDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
HIGH PRESSURE CENTERED OVER THE MID ATLANTIC COASTLINE WILL SLOWLY
DRIFT OFFSHORE THROUGH MIDWEEK. A STALLED OUT COLD FRONT DRAPED FROM
THE SAINT LAWRENCE VALLEY SOUTHWESTWARD ACROSS LAKE ONTARIO WILL LIFT
BACK NORTH OF THE REGION AS A WARM FRONT THIS AFTERNOON AND EVENING
IN RESPONSE TO DEVELOPING LOW PRESSURE ACROSS THE UPPER GREAT LAKES...
THEN THIS LATTER FEATURE WILL SLOWLY EASE ITS TRAILING COLD FRONT
ACROSS THE AREA WEDNESDAY AFTERNOON AND NIGHT.
THE INITIAL FRONTAL BOUNDARY WILL CONTINUE TO TRIGGER SCATTERED
SHOWERS AND THUNDERSTORMS AS IT LINGERS NEAR THE LOWER GREAT LAKES
THIS MORNING...WITH THESE THEN GRADUALLY DIMINISHING FROM SOUTHWEST
TO NORTHEAST THIS AFTERNOON AND EVENING AS THE BOUNDARY LIFTS AWAY
FROM OUR REGION. FOLLOWING ITS DEPARTURE...GENERALLY DRY CONDITIONS
ARE EXPECTED FOR THE BALANCE OF TONIGHT...BEFORE THE TRAILING COLD
FRONT BRINGS MORE NUMEROUS SHOWERS AND THUNDERSTORMS AS IT PASSES
THROUGH THE REGION WEDNESDAY AFTERNOON AND NIGHT.
WHILE ANY OF THE SHOWERS/STORMS COULD PRODUCE LOCALLY HIGHER WINDS AND
WAVES OVER THE NEXT COUPLE OF DAYS...IN GENERAL LIGHT TO MODEST WINDS
WILL PREVAIL ACROSS THE LOWER LAKES REGION THROUGH WEDNESDAY NIGHT...
ALONG WITH WAVES OF UNDER 3 FEET.
FOLLOWING THE PASSAGE OF THE FRONT...HIGH PRESSURE IS EXPECTED TO
BUILD ACROSS THE REGION THURSDAY AND FRIDAY WHILE BRINGING A RETURN
TO MORE SETTLED CONDITIONS...ALONG WITH CONTINUED LIGHT TO MODEST
WINDS AND MINIMAL WAVES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JJR
NEAR TERM...JJR
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...JJR
MARINE...JJR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
752 AM EDT TUE SEP 8 2015
.SYNOPSIS...
A RIDGE OF HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH EARLY
WEDNESDAY. A SLOW-MOVING COLD FRONT WILL THEN PRESS SOUTHEAST
ACROSS THE AREA LATE WEDNESDAY AND THURSDAY. A DEEPENING UPPER
LEVEL TROUGH AND ASSOCIATED COLD FRONT WILL LIKELY PUSH THROUGH
PENNSYLVANIA NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
11-3.9U IMAGERY SHOWING SOME PATCHY DENSE FOG IN THE DEEP VALLEYS
NORTH OF I-80 EARLY THIS MORNING. THE FOG SHOULD BURN OFF BY ARND
13Z PER LATEST HRRR/LAMP. CENTRAL PA WILL REMAIN BENEATH UPPER RIDGE
AXIS TODAY...WITH LARGE SCALE SUBSIDENCE AND RELATIVELY LOW PWATS
LIKELY ENSURING A MSUNNY...HOT AND DRY DAY. CAN/T COMPLETELY RULE
OUT AN ISOLD LATE DAY SHOWER OVR THE ELEVATED HEAT SOURCE OF THE
LAUREL HIGHLANDS AS LATEST HRRR SUGGESTS. HOWEVER...BELIEVE AREAL
COVERAGE OF ANY SHOWERS WOULD BE TOO LOW TO MENTION IN GRIDS
ATTM.
TEMPS SHOULD BE AT LEAST AS WARM AS YESTERDAY OR PERHAPS EVEN A
DEG OR TWO HIGHER BASED ON GEFS MEAN 925/850 TEMPS. MAXES WILL
RANGE FROM THE U80S ACROSS THE ALLEGHENY PLATEAU...TO THE L90S
ACROSS THE SUSQ VALLEY. RECORD HIGH OF 92F AT KIPT COULD BE IN
JEOPARDY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
AFTER ANOTHER VERY WARM AND TRANQUIL NIGHT...APPROACHING SHORTWAVE
AND ASSOC COLD FRONT WILL BRING A CHANCE OF SHRA/TSRA WEDNESDAY.
HIGHEST /LIKELY/ POPS ARE PAINTED ACROSS THE NW MTNS CLOSEST TO
APPROACHING COLD FRONT. ALL SHORT RANGE MDLS INDICATE THERE WILL
BE A MINIMUM IN SHOWER ACTIVITY ACROSS THE CENTRAL MTNS IN
CONJUNCTION WITH LINGERING RIBBON OF LOWER PWATS.
PARTLY CLOUDY SKIES AND SCT PM CONVECTION MAY HOLD TEMPS DOWN A
BIT FROM RECENT DAYS. HOWEVER...AIR MASS REMAINS VERY WARM WITH
MDL 8H TEMPS AOA 18C. THEREFORE...EXPECT HIGHS WELL INTO THE
80S...WITH 90F STILL POSSIBLE ACROSS THE SUSQ VALLEY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
MED RANGE MDLS ALL INDICATING INITIAL SHORTWAVE SHEARS OUT AND
LIFTS NORTH OF PA WED NIGHT. TRAILING...SLOW-MOVING COLD FRONT
SHOULD PUSH THRU CENTRAL PA WED NITE/THURSDAY. EXPECT SOME
BENEFICIAL RAINFALL OVR MOST OF THE AREA FROM THIS FEATURE AS
FRONT INTERACTS WITH HIGH MOISTURE/PWAT ANOMALIES. BLEND OF LATEST
ENSEMBLE OUTPUT SUPPORTS WIDESPREAD 0.25 TO 0.50 INCHES...WITH
LOCAL AMTS IN EXCESS OF AN INCH.
A RETURN TO FAIR WX/SEASONAL TEMPS APPEARS LIKELY FRIDAY IN WAKE
OF FRONT. HOWEVER...DIGGING TROF AND ASSOC SECONDARY COLD FRONT
APPEARS LIKELY TO SWING THRU CENTRAL PA OVER THE WEEKEND...BRINING
ANOTHER ROUND OF SHOWERY CONDS. ECENS AND OPER CANADIAN FORMING A
CUT OFF LOW OVR THE OHIO VALLEY...SIGNALING THE UNSETTLED WX COULD
LAST THRU MOST OF THE WEEKEND.
TEMPS MAY BRIEFLY FALL BLW NORMAL ARND SUN-MON...AS UPPER LOW
LIFTS THRU. HOWEVER...LATEST ECENS/NAEFS SUPPORT A RETURN TO ABOVE
NORMAL TEMPS NEXT WEEK...AS TROUGH QUICKLY LIFTS OUT AND UPPER RIDGE
BUILDS ALONG THE EAST COAST.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AREAS OF MVFR VSBYS IN FOG WILL DISSIPATE BY 13-14Z...LEAVING
ANOTHER DAY OF PREDOMINANTLY VFR CONDS. A STRAY LATE- DAY
SHRA/TSRA IS AGAIN POSSIBLE ACROSS THE NW MTNS...BUT THAT IS ABOUT
IT. WINDS WILL BE NEARLY CALM THIS MORNING...THEN BECOME LIGHT
OUT OF THE SW BY AFTN.
THINGS WILL TURN A BIT MORE UNSETTLED FOR THE SECOND HALF OF THE
WEEK...AS A COLD FRONT APPROACHES FROM THE GREAT LAKES WEDNESDAY
AND CROSSES PA ON THURSDAY.
OUTLOOK...
WED...SCATTERED LATE-DAY SHRA/TSRA POSSIBLE.
THU...MORE NUMEROUS SHRA/TSRA EXPECTED.
FRI...PATCHY MORNING FOG POSSIBLE...OTHERWISE GENERALLY VFR.
SAT...WIDELY SCATTERED LATE-DAY SHRA/TSRA POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD/CERU
AVIATION...GARTNER
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1056 AM CDT TUE SEP 8 2015
.UPDATE...
ISSUED AT 1056 AM CDT TUE SEP 8 2015
FLASH FLOOD WATCH HAS BEEN CANCELLED WITH HEAVY RAINFALL PUSHED
OUT OF OUR FORECAST AREA INTO EASTERN WISCONSIN. WILL KEEP A LOW-
END SHOWER/ISOLATED THUNDER CHANCE IN FOR PORTIONS OF NORTHEAST IA
INTO FAR SOUTHWEST WI AS RADAR WAS SHOWING SOME WEAK ECHO
UPSTREAM. OTHERWISE...LOOKS DRY GOING INTO THE AFTERNOON AS
SURFACE HIGH PRESSURE AND DRIER AIR BUILDS IN FROM THE DAKOTAS/MN.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 333 AM CDT TUE SEP 8 2015
MAIN FCST CONCERNS THIS PERIOD...SHRA/TSRA CHANCES THIS MORNING...
TEMPERATURES.
DATA ANALYSIS AT 06Z HAD THE OLD FRONTAL BOUNDARY NEAR THE WI/IL
BORDER TO NEAR KDSM/KOMA. A WEAK LOW WAS LOCATED ON THE FRONT NEAR
KOMA. PER WV IMAGERY...A SHORTWAVE WAS MOVING EAST-NORTHEAST ACROSS
OVER NEB. INCREASING LOWER LEVEL THERMO-DYNAMIC FORCING AND MOISTURE
TRANSPORT AHEAD OF THE SFC-700MB TROUGH AND LIFT AHEAD OF THE
SHORTWAVE PRODUCING INCREASING SHRA/TSRA ACROSS SOUTHWEST MN/
NORTHWEST IA. WSR-88D RAINFALL ESTIMATES OF 1-2 INCHES/HR FROM SOME
OF THE TSRA IN SOUTHWEST MN. ELSEWHERE...IT REMAINED ANOTHER WARM
AND HUMID EARLY SEPT NIGHT ACROSS MUCH OF THE UPPER MIDWEST UNDER
INCREASING CLOUD COVER.
08.00Z MODEL RUNS LOOK TO HAVE INITIALIZED WELL. SOLUTIONS QUITE
SIMILAR...AT LEAST AT 500MB...AS ONE SHORTWAVE PASSES EARLY THIS
MORNING THEN THE MAIN MID LEVEL TROUGH AXIS PASSES TONIGHT. TREND IS
TOWARD A TIGHTER CONSENSUS OF THE EARLIER RUNS THRU TONIGHT. STILL
SOME MESO-SCALE DETAIL DIFFERENCES IMPACTING PRECIP PLACEMENT/TIMING
THIS MORNING BUT THIS NOT UNEXPECTED. EVEN WITH THESE DIFFERENCES...
SHORT-TERM FCST CONFIDENCE IS GOOD THIS CYCLE.
FOR THE SHORT TERM...REGIONAL RADAR COMPOSITE SHOWING THE MORE
NORTHERN OF MODEL SOLUTIONS WITH SHRA/TSRA/QPF LOOKING BETTER EARLY
THIS MORNING. RADAR PRECIP ESTIMATES ALSO SHOWING MODEL SOLUTIONS
WITH HEAVIER QPF ALSO LOOKING BETTER. GIVEN PW VALUES OF UP TO 1.75
INCHES /2.5 STANDARD DEVIATIONS ABOVE NORMAL/ IN THE INFLOW
AIRMASS...TREND FOR STORMS TO BE EFFICIENT/HEAVY RAIN PRODUCERS
SHOULD CONTINUE AS THE FORCING/CONVECTION MOVE EAST ACROSS THE FCST
AREA THIS MORNING. RAISED QPF IN THE FCST GRIDS...BUT NOT ALL AREAS
WILL SEE 1 TO 2 INCHES OF RAIN. HOWEVER...IF THIS RAIN FALLS IN
URBAN AREAS...AREAS HIT BY HEAVY RAINS IN RECENT DAYS...OR TSRA
TRAIN/REPEAT OVER THE SAME AREA...MORE FLOODING ISSUES ARE CERTAINLY
POSSIBLE. AFTER COLLABORATION WITH NEIGHBORS...HAVE ISSUED A FLASH
FLOOD WATCH FOR MUCH OF THE FCST AREA FROM 09Z-15Z /NORTHWEST THIRD/
OR 09Z-18Z /CENTRAL AND SOUTH PARTS/ TODAY. WITH PASSAGE OF THE
SHORTWAVE AND SFC-500MB TROUGH AXIS...FORCING/LIFT AND DEEPER
MOISTURE QUICKLY MOVE EAST OF THE AREA BY LATE THIS MORNING INTO
EARLY THIS AFTERNOON. CARRIED HIGHEST SHRA/TSRA CHANCES IN THE 12-
15Z PERIOD THIS MORNING...TRENDING DOWN AND EASTWARD RATHER QUICKLY
THRU THE LATE MORNING/EARLY AFTERNOON HOURS. SFC-700MB WINDS REMAIN
LIGHT TODAY...WITH LOWER LEVEL MOISTURE/CLOUDS BEHIND THE LOW/TROUGH
AXIS LIKELY SLOW TO CLEAR OUT. HAVE RAISED CLOUD COVER IN GRIDS THRU
MUCH OF TODAY. STRONGER OF THE LOWER LEVEL DRYING/COOLING PUSHES IN
TONIGHT WITH PASSAGE OF THE MAIN MID LEVEL TROUGH AXIS. MODELS
SHOWING PW VALUES DROP TO AROUND 1/2 INCH OVER THE AREA BY 12Z WED.
WITH LOWER LEVEL COLD ADVECTION AND ANTI-CYCLONIC FLOW...SKIES
EXPECTED TO BECOME CLEAR/MOSTLY CLEAR BY LATE EVENING. LOWER LEVEL
COLD ADVECTION...LIGHT BOUNDARY LAYER WINDS AND THE MOSTLY CLEAR
SKIES...LOWS TONIGHT TRENDING TO BE MUCH CLOSER TO NORMAL THAN THOSE
OF THE PAST WEEK. STAYED WITH A BLEND OF THE GUIDANCE HIGHS/LOWS FOR
TODAY/TONIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 333 AM CDT TUE SEP 8 2015
FOR WEDNESDAY THRU THURSDAY NIGHT...
MAIN FCST CONCERNS THIS PERIOD...SHRA/TSRA CHANCES LATE WED NIGHT
INTO THU NIGHT...TEMPERATURES.
08.00Z MODEL RUNS IN GOOD AND IMPROVING AGREEMENT THIS PERIOD AS
HGTS FALL/MID LEVEL TROUGHING DEEPENS OVER THE NORTH CENTRAL CONUS.
GENERALLY TREND IS DEEPER/STRONGER WITH THE TROUGH AND SHORTWAVE
ENERGY IN IT OVER THE REGION BY THU/THU NIGHT. GIVEN THE TIGHTER
MODEL CONSENSUS...FCST CONFIDENCE THIS PERIOD IS GOOD THIS CYCLE.
QUIET...DRY...MOSTLY SUNNY...SEASONABLE DAY ON WED AS CANADIAN HIGH
PRESSURE AND A DRY LOWER LEVEL AIRMASS SLIDE ACROSS THE UPPER
MIDWEST. THIS DOES NOT LAST LONG WITH THE TROUGH ALOFT DEEPENING AND
APPROACH OF THE LEAD SHORTWAVE ENERGY. NEXT SFC TROUGH/FRONT IS
ALREADY INTO NORTHERN WI TO SOUTHWEST MN BY 12Z THU. CONSISTENT
SIGNAL FOR LOWER LEVEL MOISTURE TO QUICKLY RETURN NORTHWARD AHEAD OF
THE SFC-700MB TROUGH...ALONG WITH AN INCREASE OF LOWER LEVEL
CONVERGENCE/ISENTROPIC LIFT. SOME WEAK MUCAPE EVEN INDICATED AHEAD
OF THE TROUGH BY 12Z THU. SMALL SHRA/ISOLATED TSRA CHANCE OVER THE
NORTHWEST HALF OF THE FCST AREA LATER WED NIGHT REASONABLE FOR NOW.
MOISTURE/CAPE AHEAD OF THE LOWER LEVEL TROUGH CONTINUE TO INCREASE
ON THU. SOME TIMING DIFFERENCES WITH PROGRESSIVENESS OF THE SFC-
700MB TROUGH/FRONT BY 00Z FRI. HOWEVER TIGHTENING CONSENSUS FOR ENOUGH
LIFT/MOISTURE FOR SOME SHRA/TSRA TO ACCOMPANY IT AS IT MOVES ACROSS
THE FCST AREA THU/THU NIGHT. STAYED WITH THE CONSENSUS SHRA/TSRA
CHANCES FOR THU/THU NIGHT FOR NOW...PENDING BETTER TIMING AGREEMENT
AMONG THE MODELS. STRONGER SHOT OF LOW LEVEL COLD ADVECTION FOLLOWS
IN THE WAKE OF THE TROUGH/FRONT FOR THU NIGHT...WITH THU NIGHT LOWS
TRENDING BELOW NORMAL. USED A BLEND OF THE GUIDANCE HIGHS/LOWS FOR
WED THRU THU NIGHT.
FOR FRIDAY THRU MONDAY...DAYS 4 TO 7...
MAIN FCST CONCERNS THIS PERIOD...COOLER TEMPERATURES...SMALL SHRA
CHANCES BY SUN NIGHT/MON.
MEDIUM RANGE MODEL RUNS OF 08.00Z SHOW IMPROVING AGREEMENT FOR
TROUGHING TO DEEPEN OVER THE GREAT LAKES FRI THRU SAT...WITH DEEP
NORTHERLY FLOW OVER THE REGION BY 00Z SUN. REASONABLE CONSENSUS FOR
THE TROUGHING TO DIG INTO THE EASTERN CONUS SAT NIGHT/SUN...WITH
SHORTWAVE RIDGING/RISING HGTS BUILDING INTO THE UPPER MIDWEST BEHIND
IT. BY SUN NIGHT/MON SOME CONSISTENCY FOR HGTS TO FALL AGAIN AS A
STRONGER SHORTWAVE TRACKS EAST ALONG THE US/CAN BORDER. WITH THE
BETTER MODEL CONSENSUS...THE LONG TERM FCST CONFIDENCE IS ABOVE
AVERAGE THIS CYCLE.
THIS PERIOD STARTS OUT WITH CAN HIGH PRESSURE BUILDING INTO THE
REGION. DEEP NORTHWEST TO NORTH FLOW CONTINUES TO SPREAD LOW LEVEL
COLD ADVECTION SPREADING ACROSS THE AREA WITH 850MB TEMPS BY 00Z SAT
1 TO 2 STANDARD DEVIATIONS BELOW NORMAL. FRI THRU SAT CONTINUES TO
SHAPE UP AS A DRY...COOL PERIOD WITH TEMPS SOME 5F TO 10F BELOW
NORMAL. SFC-850MB HIGH WOULD MOVE SOUTH OF THE AREA BY SUNDAY...WITH
SOME LOW LEVEL WARM ADVECTION RETURNING. TROUGHING/SHORTWAVE MOVING
ACROSS SOUTHERN CAN SUN NIGHT/MON WOULD DRAG A FRONTAL BOUNDARY INTO
THE REGION...WITH AN INCREASE OF MOISTURE/CONVERGENCE/LIFT AND SOME
MUCAPE AHEAD OF IT. PLENTY OF TIMING DIFFERENCES BY MON...BUT A
SMALL SHRA/TSRA CHANCE ACROSS MAINLY THE NORTH END OF THE FCST AREA
BY LATER SUN NIGHT/MON REASONABLE AT THIS POINT. MODEL/ENSEMBLE
CONSENSUS OF HIGHS/LOWS FOR FRI THRU MON SEEMS TO HAVE THEM WELL
TREND AT THIS TIME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1143 PM CDT MON SEP 7 2015
WATCHING THE CONVECTION SLOWLY FILL IN ACROSS NORTHWEST IOWA AND
SOUTHWEST MINNESOTA AHEAD OF THE SHORT WAVE TROUGH COMING OUT OF
NEBRASKA. SEVERAL OF THE HI-RES MESO MODELS NOW SUGGEST THIS AREA
WILL CONTINUE TO EXPAND AND SWING THOUGH THE INTERSTATE 90 CORRIDOR
LATE TONIGHT INTO EARLY TUESDAY MORNING. HAVE THUS TRENDED THE
FORECAST TOWARD THESE SOLUTIONS OF BRINGING SOME LEADING SHOWERS
WITH A VCSH BEFORE THE MAIN BAND OF SHOWERS AND STORMS COMES IN. THE
08.03Z RAP FORECAST SOUNDINGS SUGGEST THE POTENTIAL FOR IFR
CONDITIONS AS THIS COMPLEX OF STORMS MOVES THROUGH AND IF IT EVOLVES
AS THE MESO MODELS SUGGEST...THIS SEEMS ENTIRELY REALISTIC. THE
COMPLEX SHOULD MOVE OUT FAIRLY QUICKLY TUESDAY MORNING BUT EXPECTING
THE IFR CEILINGS TO REMAIN UNTIL LATE AFTERNOON UNTIL SOME DRIER AIR
STARTS TO WORK IN FROM THE NORTHWEST TO ALLOW THE CONDITIONS TO GO
UP TO VFR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...DAS
SHORT TERM...RRS
LONG TERM....RRS
AVIATION.....04
HYDROLOGY....RRS
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
210 PM MST TUE SEP 8 2015
&&
.SYNOPSIS...
ISOLATED SHOWERS AND THUNDERSTORMS CAN BE EXPECTED AGAIN
TONIGHT...FAVORING SOUTHWEST ARIZONA AND SOUTHWEST CA. CLOUDS AND
HUMIDITY WILL INCREASE FROM WEDNESDAY INTO THURSDAY...RESULTING IN
AN INCREASE IN RAIN POTENTIAL DURING THIS PERIOD. TEMPERATURES WILL
BE LOWER AS WELL. HIGH PRESSURE AND DRIER AIR MOVING INTO THE
REGION WILL THEN REDUCE RAINFALL CHANCES AND ALLOW TEMPERATURES TO
RECOVER TO ABOVE-NORMAL VALUES FROM FRIDAY ONWARD INTO THE UPCOMING
WEEKEND. INCREASED RAINFALL CHANCES AND COOLER TEMPERATURES ARE THEN
POSSIBLE EARLY NEXT WEEK AS LOW PRESSURE MOVES INTO THE REGIONS FROM
THE WEST.
&&
.DISCUSSION...
.TONIGHT THROUGH THURSDAY... HURRICANE LINDA...WHICH IS CURRENTLY
FORECAST BY THE NHC TO CONTINUE TO MOVE NORTHWESTWARD WELL OFF THE
BAJA WEST COAST AND SLOWLY WEAKEN OVER THE NEXT FEW DAYS...IS
EXPECTED TO PLAY AN INCREASINGLY IMPORTANT RULE IN OUR WEATHER OVER
THE NEXT SEVERAL DAYS. CURRENT MODEL SUITES CONTINUE TO FORECAST A
DEEP MOISTURE SURGE WILL MOVE NORTHWARD UP THE GULF OF CALIFORNIA
TONIGHT AND WEDNESDAY...BETWEEN LINDA AND STRONG HIGH PRESSURE
RIDGING OVER NORTHWEST MAINLAND MEXICO...THEN INTO SE CA/SOUTHERN AZ
ON WEDNESDAY NIGHT AND THURSDAY. VERY HIGH PWATS...BETWEEN 2.00 AND
2.25 INCHES ARE EXPECTED TO SURGE NORTHWARD INTO THE REGION. AHEAD
OF THE MOISTURE SURGE...TONIGHT IS EXPECTED TO BE FAIRLY
QUIET...WITH THE LATEST HRRR HIGH-RES MODEL RUN SHOWING ISOLATED
THUNDERSTORM DEVELOPMENT OVER SE CA AND SW THIS AFTERNOON AND
EVENING. HIGH PRESSURE RIDGING IS EXPECTED TO KEEP SOUTH-CENTRAL
ARIZONA MAINLY THUNDERSTORM-FREE THIS AFTERNOON...WITH PERHAPS ONE
OR TWO STORMS DEVELOPING THIS EVENING IF OUTFLOWS FROM STORMS TO THE
WEST MANAGE TO MAKE THEIR WAY INTO THE REGION.
TOMORROW AND TOMORROW NIGHT SHOULD SEE AS INCREASE IN CONVECTIVE
ACTIVITY AS THE MAIN MOISTURE SURGE ARRIVES. HOWEVER...IT APPEARS
THAT THE CONVECTIVE ACTIVITY MAY BE MOSTLY WIDESPREAD SHOWER
ACTIVITY...WITH JUST SOME ISOLATED THUNDERSTORMS...SINCE THE MID AND
UPPER LEVELS OF THE ATMOSPHERE ARE EXPECTED TO REMAIN QUITE WARM
(500MB TEMPS IN THE -5-6C RANGE)...AND THERE WILL BE CONSIDERABLE
CLOUDINESS MOVING INTO THE REGION...WHICH WILL GREATLY INHIBIT
DAYTIME HEATING. THE LATEST GFS FORECAST SOUNDING FOR PHOENIX ALSO
IS SHOWING A CAPPING INVERSION BETWEEN 700 AND 850MB TOMORROW
AFTERNOON. IT APPEARS THE BEST CHANCE FOR MEASURABLE RAINFALL WILL
BE TOMORROW NIGHT...WHEN THE MOISTURE IS DEEPEST AND A WEAK
SHORTWAVE MOVES NORTHWARD INTO THE REGION. IF ANY THUNDERSTORMS DO
FORM...THE VERY MOIST ENVIRONMENT WILL ALLOW THEM TO BE VERY
EFFICIENT RAINFALL PRODUCERS...WITH LOCALIZED FLOODING POSSIBLE.
THURSDAY WILL LIKELY SEE A GRADUAL REDUCTION IN SHOWER/THUNDERSTORM
ACTIVITY AS THE SHORTWAVE WEAKENS...AVAILABLE MOISTURE LEVELS
DECREASE...AND HIGH PRESSURE ALOFT BEGINS TO SHIFT BACK OVER THE
REGION. HIGH TEMPERATURES TOMORROW AND THURSDAY WILL LIKELY BE KEPT
BELOW NORMAL BY ALL THE CLOUDS AND SHOWERS...WITH MANY LOWER DESERT
HIGHS REMAINING IN THE 90S...BUT WITH DEWPOINTS WELL UP IN THE 60S
AND 70S MAKING IT FEEL QUITE MUGGY.
.FRIDAY THROUGH SUNDAY... MAINLY DRY CONDITIONS AND SOMEWHAT WARMER
TEMPERATURES ARE EXPECTED OVER SOUTH-CENTRAL ARIZONA DURING THIS
TIME PERIOD...AS HIGH PRESSURE ALOFT...AND SOMEWHAT DRIER AIR MOVES
INTO THE REGION. SW AZ AND SE CA WILL LIKELY SEE ISOLATED CONVECTIVE
ACTIVITY EACH DAY...AS LIGHT SOUTHERLY FLOW AHEAD OF AN UPPER
LOW...WHICH IS EXPECTED TO ABSORB THE REMAINS OF LINDA...KEEPS
MOISTURE LEVELS ELEVATED OVER THAT REGION. TEMPERATURES WILL LIKELY
REBOUND INTO THE 105-108F RANGE AT MOST LOWER DESERT LOCATIONS BY
SATURDAY AND SUNDAY...WHICH IS A BIT ABOVE NORMAL FOR THIS TIME OF
YEAR.
.MONDAY AND TUESDAY... AN INCREASE IN RAINFALL CHANCES...AND
SOMEWHAT COOLER TEMPERATURES IS POSSIBLE DURING THIS PERIOD AS THE
1ST STRONG UPPER LOW OF THE FALL SEASON APPROACHES THE PAC NW
COAST..AND BEGINS TO KICK THE AFOMENTIONED SOUTHERN CA UPPER LOW
INLAND INTO THE DESERT SOUTHWEST. ALTHOUGH MOST OF THE GFS ENSEMBLE
MEMBERS DO SHOW THE UPPER LOW MOVING INLAND INTO OUR REGION...THERE
IS STILL QUITE A BIT OF SPREAD CONCERNING THE TIMING OF THIS EVENT.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
LIGHT SHOWERS AND THICKER CLOUD COVER HAS REMAINED SOUTH OF THE
PHOENIX AREA THUS FAR BUT SOME INCREASED MID CLOUDS ARE STARTING TO
CREEP INTO THE REGION AS OF 17Z. WILL MAINTAIN SOME DEGREE OF BKN
CIGS AT ALL SITES THROUGH THE AFTERNOON/EVENING HOURS BUT IT APPEARS
STORM CHANCES ARE MINIMAL AND TOO LOW TO MENTION OUTRIGHT IN ANY OF
THE TAFS. THINKING THAT THERE WILL BE A BIG PUSH OF MOISTURE AND
CLOUD COVER INTO THE REGION LATE TONIGHT. QUITE A FEW MODELS
INDICATING WIDESPREAD 5-6KFT CIGS ACROSS THE REGION AFTER 07Z AND I
LOWERED CEILINGS A BIT FROM THE INHERITED FORECAST. RAIN CHANCES
STILL LOOK LOW LATE TONIGHT...THUS THE PRIMARY IMPACTS WILL BE
CONFINED TO LOWER CIGS.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
SKIES REMAIN MOSTLY CLEAR THIS MORNING AND THAT COULD ALLOW FOR STORM
DEVELOPMENT LATER THIS AFTERNOON. MOST LIKELY LOCATION TO SEE STORMS
WOULD BE BLH AND I RETAINED THE MENTION OF VCTS LATE THIS
AFTERNOON/EVENING. STORMS SHOULD DISSIPATE BEFORE THEY REACH IPL.
AFTER THIS EVENING...EXPECT WIDESPREAD BKN-OVC CIGS TO PREVAIL
THROUGH AT LEAST LATE MORNING WEDNESDAY AS INCREASED MOISTURE MOVES
INTO THE AREA.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
FRIDAY THROUGH TUESDAY...
MOISTURE WILL GRADUALLY DIMINISH THROUGH THE WEEKEND INTO NEXT WEEK
BUT THERE WILL REMAIN AT LEAST A SLIGHT CHANCE OF MOUNTAIN SHOWERS
AND THUNDERSTORMS THROUGH NEXT WEEK. HUMIDITIES WILL FALL INTO THE
15-25 PERCENT RANGE EACH AFTERNOON WITH GOOD OVERNIGHT RECOVERIES
EXPECTED. WINDS WILL FAVOR THEIR TYPICAL DIURNAL UPSLOPE/DOWNVALLEY
PATTERNS.
&&
.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT ACCORDING TO STANDARD PROCEDURES.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...PERCHA
AVIATION...LEINS
FIRE WEATHER...LEINS
AREA FORECAST DISCUSSION...UPDATED
NWS PHOENIX AZ
1021 AM MST TUE SEP 8 2015
.UPDATE...UPDATED AVIATION AND FIRE WEATHER DISCUSSIONS...
&&
.SYNOPSIS...
ISOLATED SHOWERS AND THUNDERSTORMS CAN BE EXPECTED AGAIN
TODAY...FAVORING SOUTHWEST ARIZONA. CLOUDS AND HUMIDITY WILL INCREASE
TUESDAY NIGHT AND WEDNESDAY ALONG WITH A MODEST INCREASE IN RAIN
POTENTIAL LINGERING THROUGH THURSDAY. TEMPERATURES WILL BE LOWER AS
WELL. BY THE END OF THE WEEK TEMPERATURES WILL BE INCREASING AS DRIER
AIR MOVES INTO THE REGION. STORM CHANCES LIMITED TO THE HIGHER
TERRAIN FRIDAY THROUGH MONDAY.
&&
.DISCUSSION... A RATHER WARM...AND MUGGY MORNING (FOR EARLY SEPT)
ACROSS OUR CWA TODAY AS SOUTHWESTERLY FLOW ALOFT PULLS CONSIDERABLE
MID-LEVEL MOISTURE INLAND FROM THE TROPICAL EASTERN PACIFIC. THE
COMBINATION OF THIS MID-LEVEL MOISTURE ALONG WITH A WEAK SHORTWAVE
THAT IS MOVING WESTWARD ACROSS NORTHERN AZ IS TRIGGERING ISOLATED-
SCATTERED SHOWER/THUNDERSTORM ACTIVITY ACROSS SOUTHWEST MARICOPA
COUNTY...WITH ANOTHER AREA OF CONVECTION ACROSS SE PINAL
COUNTY...WHICH IS UNDERNEATH THE PLUME OF DEEPEST MOISTURE WHICH CAN
BE SEEN ON THE LATEST IR SATELLITE IMAGERY. GIVEN THESE LATEST
TRENDS...AND THE CURRENT HRRR HIGH-RES MODEL FORECAST...HAVE DECIDED
TO RAISE POPS A BIT ACROSS SOUTHERN MARICOPA AND NE PINAL COUNTIES
THROUGH THE REST OF THE MORNING HOURS. IT STILL LOOKS LIKE WE WILL
HAVE A BIT OF A BREAK IN THE SHOWER ACTIVITY EARLY THIS AFTERNOON
BEFORE MORE SHOWERS/TSTORMS DEVELOP...MAINLY OVER SW AZ/SE CA LATER
THIS AFTERNOON AND THIS EVENING. AS FAR AS TEMPERATURE/DEWPOINT TRENDS
ARE CONCERNED...OUR HOURLY GRIDS SEEM TO BE HOLDING UP WELL...AND NO
FURTHER UPDATES ARE PLANNED.
&&
.PREVIOUS DISCUSSION... TODAY THROUGH THURSDAY...STRONG
SOUTHWESTERLY FLOW ALOFT CONTINUES OVER THE FORECAST AREA AS WE ARE
SITUATED BETWEEN A HIGH CENTERED OVER FAR NORTHERN MEXICO AND A
TROUGH OFF THE BAJA COAST. THE OTHER SIGNIFICANT FLOW FEATURE OF
INTEREST IS HURRICANE LINDA WHICH WAS CENTERED ABOUT 300 MILES
SOUTHWEST OF THE SOUTHERN TIP OF BAJA EARLY THIS MORNING. CLOSER TO
HOME A BAND OF CLOUDS WAS COVERING MUCH OF THE SOUTHEAST HALF OF
ARIZONA WITH SOME EMBEDDED VERY LIGHT SHOWERS IN A NARROW CORRIDOR
OVER PORTIONS OF MARICOPA...PINAL...AND GILA COUNTIES. THE
CLOUDINESS IS LIKELY BEING AIDED BY THE RIGHT ENTRANCE REGION OF THE
JET INTERACTING WITH RESIDENT MOISTURE ALONG WITH A LITTLE BIT OF
HIGH LEVEL MOISTURE FROM LINDA. MODELS ARE IN GOOD AGREEMENT FOR
TODAY IN SHOWING A WESTWARD SHIFT OF THE HIGH AND A NORTHWARD
DISPLACEMENT OF THE JET. THEY ALSO DO NOT SHOW MUCH OF ANY INCREASE
IN LOWER LEVEL MOISTURE. THUS THEY GENERALLY SHOW A DOWNTREND IN
CAPE FOR TODAY COMPARED TO MONDAY. ONE EXCEPTION IS SOUTHEAST
CALIFORNIA WHERE CAPE EXPANDS FURTHER INTO THE LOWER DESERTS THERE.
THIS ADDS UP TO SLIGHT CHANCES OF SHOWERS AND THUNDERSTORMS ACROSS
THE LOWER ELEVATIONS OF OUR FORECAST AREA...MARGINALLY BETTER OVER
THE HIGHER TERRAIN. TUESDAY NIGHT THROUGH THURSDAY THE FORECAST IS
QUITE CHALLENGING. IN GENERAL...THE MODELS SHOW A GULF SURGE LEADING
TO A SIGNIFICANT INCREASE IN LOWER LEVEL MOISTURE. THEY ALSO SHOW A
SIGNIFICANT INCREASE IN MID AND HIGH LEVEL CLOUDINESS...EMANATING
FROM LINDA. HOWEVER THERE ARE SOME NOTABLE DIFFERENCES IN THE TIMING
AND MAGNITUDE OF THE MOISTURE INCREASE AS WELL AS TIMING AND TRACK
OF ONE OR MORE PERTURBATIONS MOVING NORTHWARD ACROSS THE MEXICO
BORDER. THE NAM IS FASTER WITH THE MOISTURE INCREASE THAN THE GFS
AND ECMWF. IT IS ALSO FASTER WITH THE ARRIVAL OF A SHORT WAVE FROM
BAJA AND TRACKS IT FURTHER EAST FOR MORE IMPACT ON EASTERN PORTIONS
OF OUR AREA. DESPITE ALL OF THAT THE NAM MODEL RUN QPF IS
MODEST...BETTER OVER SOUTHEAST ARIZONA. IN FACT ALL OF THE MODELS
SHOW MODEST QPF INCLUDING THE GFS WHICH TENDS TO BE
OVERDONE...THOUGH IT HAS A COUPLE OF LOCALIZED HIGH TERRAIN
BULLSEYES. THE MAIN REASONS FOR THE UNDERWHELMING MODEL PRECIP
FORECAST IS LACK OF CAPE DUE TO POOR LAPSE RATES AS WELL AS LACK OF
DYNAMICAL FORCING. THUS OUR POPS REMAIN MODEST. THERE COULD BE
SHOWERS AT ANY TIME AND IF ANY OF THEM MANAGE TO HAVE SOME STRENGTH
THEY WILL BE ABLE TO PRODUCE A LOT OF PRECIP IN A VERY LOCALIZED
AREA. AS FOR TEMPERATURES...ANTICIPATE SLIGHTLY WARMER CONDITIONS
TODAY. COOLER CONDITIONS WEDNESDAY WITH MORE CLOUDINESS AND
HUMIDITY...MOST NOTICEABLY OVER SOUTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA...AND SLIGHTLY WARMER THURSDAY AS CLOUDS START TO TREND
DOWN. MEANWHILE...LINDA WILL REMAIN OFFSHORE AND WEAKEN AS IT MOVES
NORTHWESTWARD.
FRIDAY THROUGH MONDAY...
THE FLOW BECOMES MORE AMPLIFIED LATE IN THE WEEK. WITH A RIDGE AXIS
OVER THE INTERIOR WEST. WITH A NORTHERLY COMPONENT TO THE FLOW...A
DRYING TREND IS EXPECTED. ECMWF IS SLOWER WITH THE DRYING THAN THE
GFS BUT IT TENDS TO BE OVERLY GENEROUS WITH MOISTURE. ONLY SLIGHT
CHANCE POPS ARE LEFT OVER THE HIGHER TERRAIN OF SOUTH-CENTRAL ARIZONA
FRIDAY AND SATURDAY. EARLY NEXT WEEK...WEST COAST TROUGHING
REDEVELOPS AND THE RIDGE SHIFTS EASTWARD A BIT SUCH LEADING TO A
SOUTHERLY COMPONENT TO THE FLOW. INTRODUCED SOME SLIGHT CHANCE POPS
SUNDAY AND MONDAY OVER FAVORED HIGHER TERRAIN AREAS AS EVEN THE GFS
SHOWS MORE MOISTURE AVAILABLE.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
LIGHT SHOWERS AND THICKER CLOUD COVER HAS REMAINED SOUTH OF THE
PHOENIX AREA THUS FAR BUT SOME INCREASED MID CLOUDS ARE STARTING TO
CREEP INTO THE REGION AS OF 17Z. WILL MAINTAIN SOME DEGREE OF BKN
CIGS AT ALL SITES THROUGH THE AFTERNOON/EVENING HOURS BUT IT APPEARS
STORM CHANCES ARE MINIMAL AND TOO LOW TO MENTION OUTRIGHT IN ANY OF
THE TAFS. THINKING THAT THERE WILL BE A BIG PUSH OF MOISTURE AND
CLOUD COVER INTO THE REGION LATE TONIGHT. QUITE A FEW MODELS
INDICATING WIDESPREAD 5-6KFT CIGS ACROSS THE REGION AFTER 07Z AND I
LOWERED CEILINGS A BIT FROM THE INHERITED FORECAST. RAIN CHANCES
STILL LOOK LOW LATE TONIGHT...THUS THE PRIMARY IMPACTS WILL BE
CONFINED TO LOWER CIGS.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
SKIES REMAIN MOSTLY CLEAR THIS MORNING AND THAT COULD ALLOW FOR STORM
DEVELOPMENT LATER THIS AFTERNOON. MOST LIKELY LOCATION TO SEE STORMS
WOULD BE BLH AND I RETAINED THE MENTION OF VCTS LATE THIS
AFTERNOON/EVENING. STORMS SHOULD DISSIPATE BEFORE THEY REACH IPL.
AFTER THIS EVENING...EXPECT WIDESPREAD BKN-OVC CIGS TO PREVAIL
THROUGH AT LEAST LATE MORNING WEDNESDAY AS INCREASED MOISTURE MOVES
INTO THE AREA.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
FRIDAY THROUGH TUESDAY...
MOISTURE WILL GRADUALLY DIMINISH THROUGH THE WEEKEND INTO NEXT WEEK
BUT THERE WILL REMAIN AT LEAST A SLIGHT CHANCE OF MOUNTAIN SHOWERS
AND THUNDERSTORMS THROUGH NEXT WEEK. HUMIDITIES WILL FALL INTO THE
15-25 PERCENT RANGE EACH AFTERNOON WITH GOOD OVERNIGHT RECOVERIES
EXPECTED. WINDS WILL FAVOR THEIR TYPICAL DIURNAL UPSLOPE/DOWNVALLEY
PATTERNS.
&&
.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT ACCORDING TO STANDARD PROCEDURES.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...PERCHA/AJ
AVIATION...LEINS
FIRE WEATHER...LEINS
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
955 AM PDT TUE SEP 8 2015
.SYNOPSIS...
HIGH PRESSURE ALOFT WILL BRING HOT DAYTIME WEATHER THROUGH THURSDAY...
FOLLOWED BY SLOW COOLING SPREADING INLAND FROM THE COAST THROUGH
EARLY NEXT WEEK ALONG WITH SLOW DRYING. TROPICAL MOISTURE WILL
BRING A CHANCE OF AFTERNOON AND EARLY EVENING THUNDERSTORMS TO THE
MOUNTAINS...DESERTS...AND PORTIONS OF THE INLAND EMPIRE INTO FRIDAY
WITH CHANCES GREATEST TODAY THROUGH THURSDAY. AN INCREASED FLASH
FLOOD THREAT WILL ACCOMPANY THESE THUNDERSTORMS.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
A MOIST AND UNSTABLE ATMOSPHERE REMAINS IN PLACE THIS MORNING...WITH
THE 12Z MIRAMAR SOUNDING SHOWING 1.77 INCHES OF PRECIPITABLE WATER
AND 1058 J/KG OF MOST UNSTABLE CAPE...WITH SOUTH TO SOUTHEAST FLOW
IN THE LOW LEVELS AND SOUTHWEST FLOW ALOFT. WITH THIS ATMOSPHERIC
SET-UP...AND THE AMPLE SUNSHINE THAT THE REGION WILL EXPERIENCE THIS
MORNING...THUNDERSTORMS SHOULD ERUPT OVER THE MOUNTAINS AND DESERTS
THIS AFTERNOON INTO EARLY EVENING. THE 15Z HRRR SHOWS THE FIRST
THUNDERSTORMS POPPING OFF OVER THE MOUNTAINS BY 1 PM.
WATER VAPOR SATELLITE SHOWS HURRICANE LINDA SOUTHWEST OF SOUTHERN
BAJA...WITH SOME WISPS OF CLOUDS ASSOCIATED WITH LINDA MOVING OVER
SAN DIEGO COUNTY THIS MORNING. A RIDGE ALOFT IS CURRENTLY BUILDING
OVER THE REGION...AND WILL CONTINUE TO BUILD THROUGH AT LEAST
THURSDAY. THE RIDGE...IN ADDITION TO SOME INCREASING MOISTURE AT THE
SURFACE...WILL MAKE FOR HOT AND MUGGY DAYS FOR MOST AREAS. SURFACE
DEW POINTS ARE ALREADY IN THE MID 60S IN WESTERN SAN DIEGO COUNTY
AND ORANGE COUNTY. MORNING TEMPERATURES ARE ALREADY SEVERAL DEGREES
HIGHER THAN 24 HOURS AGO. WITH THE MORNING UPDATE...HIGH
TEMPERATURES FOR THE SAN DIEGO COUNTY VALLEYS AND COAST WERE
INCREASED BY 5 DEGREES TO BE MORE IN-LINE WITH WHAT THE ECMWF...NAM
AND GFS MOS WERE INDICATING. THUS...THE HEAT ADVISORY FOR THOSE
AREAS WAS CHANGED TO START TODAY. THE HEAT ADVISORIES FOR THE INLAND
EMPIRE...SANTA ANA MOUNTAINS/FOOTHILLS AND INLAND ORANGE COUNTY
REMAIN THE SAME.
OVER THE NEXT FEW DAYS...LINDA WILL WEAKEN AND MOVE NORTHWEST...WITH
LOW-TO-MID LEVEL WINDS BECOMING MORE EAST TO SOUTHEAST...AND
CONTINUALLY HIGHER MOISTURE ADVECTING INTO THE REGION. THE EASTERLY
FLOW COULD RESULT IN GREATER CHANCES FOR THE VALLEYS TO GET
THUNDERSTORMS...PARTICULARLY THURSDAY WHEN THE WRF INDICATES 700-500
MB WIND OF 15-20 KT OUT OF THE EAST. THE INLAND EMPIRE MAY HAVE A
DIFFICULT TIME GETTING THUNDERSTORMS TODAY...AS THE WRF DOES NOT
SHOW MUCH OF A CONVERGENCE BOUNDARY SETTING UP NEAR ELSINORE.
HOWEVER...THE WRF DOES SHOW A BETTER CONVERGENCE BOUNDARY SETTING UP
IN THAT AREA ON WEDNESDAY...SO THAT WOULD INDICATE A BETTER CHANCE
FOR THUNDERSTORMS FOR THE INLAND EMPIRE FOR THAT DAY.
BY TOMORROW...MODELS INDICATE PRECIPITABLE WATER INCREASING TO 1.9
INCHES...AND POSSIBLY NEAR 2 INCHES ON THURSDAY. THE THUNDERSTORMS
WILL BRING AN INCREASED FLASH FLOOD THREAT. SEE THE HYDROLOGY
SECTION BELOW FOR MORE DETAILS ON THE FLOODING POTENTIAL. BY
FRIDAY...THE GFS KEEPS THE REMNANT CIRCULATION FROM LINDA CLOSER TO
THE COAST THAN THE OTHER MODELS...AND SO PRECIPITABLE WATER DOES NOT
DECREASE MUCH...WHILE THE NAM12 AND SREF HAVE THE LINDA CIRCULATION
FARTHER TO THE SOUTHWEST...WITH PRECIPITABLE WATER DECREASING TO 1.5-
1.7 INCHES. THE GFS CONTINUES TO KEEP A FAIR AMOUNT OF MOISTURE IN
THE AREA SATURDAY...AND POSSIBLY ENOUGH SUNDAY AS WELL FOR SOME
THUNDERSTORMS OF THE MOUNTAINS AND POSSIBLY DESERTS. MAY NEED TO ADD
THUNDERSTORMS TO THE FORECAST FOR SATURDAY AND SUNDAY.
MEANWHILE...NIGHT AND MORNING MARINE LAYER STRATUS SHOULD REMAIN
ABSENT FOR A WHILE...DUE TO THE RIDGE AND INTERFERENCE FROM ALL OF
THE MID AND UPPER LEVEL MOISTURE.
GRADUAL COOLING LOOKS TO TAKE PLACE FRIDAY THROUGH EARLY NEXT WEEK
AS THE RIDGE ALOFT SLOWLY WEAKENS AND A TROUGH EVENTUALLY MOVES IN
ALONG THE WEST COAST EARLY NEXT WEEK.
&&
.HYDROLOGY...
FLASH FLOOD WATCH GOES INTO EFFECT AT NOON TODAY AND CONTINUES
THROUGH THURSDAY FOR THE MOUNTAINS...DESERTS AND PORTIONS OF THE
INLAND EMPIRE...AS THE ATMOSPHERE WILL REMAIN MOIST AND UNSTABLE
THROUGH THAT TIME. THIS WILL CREATE THE CHANCES FOR THUNDERSTORMS
PRODUCING HEAVY RAIN. THE WINDS ALOFT WILL BE LIGHT AS
WELL...RESULTING IN SLOW MOVING STORMS WHICH WILL INCREASE THE
THREAT OF FLASH FLOODING FURTHER. RAIN RATES OF 1 TO 2 INCHES PER
HOUR WILL BE POSSIBLE UNDERNEATH THE HEAVIER STORMS. THE FLASH FLOOD
THREAT STARTS TO DIMINISH FRIDAY INTO THE WEEKEND AS MOISTURE SLOWLY
DECREASES.
&&
.AVIATION...
081530Z...COASTAL...NO VIS RESTRICTIONS WILL OCCUR THROUGH WED
MORNING WITH OCCASIONAL CLOUDS ONLY ABOVE 10000 FEET MSL.
VALLEYS/MOUNTAINS/DESERTS...THUNDERSTORMS WILL DEVELOP THIS
AFTERNOON WITH TIMING 20Z TO 02Z...MOST NUMEROUS OVER THE
MOUNTAINS...BUT ISOLATED THUNDERSTORMS COULD OCCUR IN THE DESERTS
AND VALLEY FOOTHILLS. BASES WILL BE 9000 FT MSL WITH TOPS TO 45000
FT MSL POSSIBLE...WITH STRONG UP/DOWNDRAFTS AND LOCAL SURFACE GUSTS
OVER 40 KT. THERE IS A CHANCE KPSP AND KTRM COULD HAVE VCNTY
THUNDERSTORMS. THUNDERSTORMS COULD DEVELOP IN THE SAME AREAS WED
AFTERNOON. OUTSIDE OF THUNDERSTORMS...NO VIS RESTRICTIONS WILL
OCCUR...AND MOST CLOUDS WILL BE ABOVE 8000 FEET MSL.
&&
.MARINE...
830 AM...NO HAZARDOUS MARINE WEATHER IS EXPECTED THROUGH SATURDAY.
&&
.BEACHES...
830 AM...THE LONG-PERIOD SOUTHWEST SWELL WILL GRADUALLY LOWER TODAY
BUT CONTINUE TO PRODUCE ELEVATED SURF AND STRONG RIP AND LONGSHORE
CURRENTS...MAINLY IN ORANGE COUNTY TODAY. THE BEACH HAZARDS
STATEMENT IS IN EFFECT FOR ORANGE COUNTY BEACHES THROUGH 8 PM THIS
EVENING...SEE LAXCFWSGX FOR DETAILS. FOR MORE SURF DETAILS SEE
LAXSRFSGX. A NEW SOUTH SOUTHEAST SWELL COMING FROM HURRICANE LINDA
WILL ARRIVE THURSDAY AND WILL BRING SOME 5-7 FOOT SURF...LOCALLY
HIGHER...IN NORTHERN ORANGE COUNTY THU/FRI.
&&
.SKYWARN...
SKYWARN ACTIVATION IS REQUESTED FOR THE MOUNTAINS...DESERTS...AND
PORTIONS OF THE INLAND EMPIRE FOR TODAY FROM NOON THROUGH 7 PM
THIS EVENING. ACTIVATION MAY BE NEEDED FOR SIMILAR AREAS AND TIMES
FOR WEDNESDAY AND THURSDAY AS WELL.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...FLASH FLOOD WATCH FROM NOON PDT TODAY THROUGH THURSDAY EVENING
FOR COACHELLA VALLEY-RIVERSIDE COUNTY MOUNTAINS-SAN
BERNARDINO COUNTY MOUNTAINS-SAN BERNARDINO AND RIVERSIDE
COUNTY VALLEYS-THE INLAND EMPIRE-SAN DIEGO COUNTY DESERTS-
SAN DIEGO COUNTY MOUNTAINS-SAN GORGONIO PASS NEAR BANNING AND
APPLE AND LUCERNE VALLEYS.
HEAT ADVISORY FROM NOON TODAY TO 6 PM PDT WEDNESDAY FOR SAN DIEGO
COUNTY COASTAL AREAS-SAN DIEGO COUNTY VALLEYS.
HEAT ADVISORY FROM NOON TODAY TO 6 PM PDT THURSDAY FOR ORANGE
COUNTY INLAND AREAS-SAN BERNARDINO AND RIVERSIDE COUNTY
VALLEYS-THE INLAND EMPIRE-SANTA ANA MOUNTAINS AND FOOTHILLS.
BEACH HAZARDS STATEMENT THROUGH THIS EVENING FOR ORANGE COUNTY
COASTAL AREAS.
PZ...NONE.
&&
$$
PUBLIC/HYDROLOGY...HARRISON
AVIATION/MARINE/BEACHES...MAXWELL
AREA FORECAST DISCUSSION
NWS ALBANY NY
128 PM EDT TUE SEP 8 2015
.SYNOPSIS...
HIGH PRESSURE NEAR THE MID ATLANTIC REGION WILL CONTINUE
TO PROVIDE UNSEASONABLY HOT WEATHER UNTIL TOMORROW. A WEAK
DISTURBANCE THIS AFTERNOON WILL BRING ISOLATED TO SCATTERED SHOWERS
AND THUNDERSTORMS FROM THE CAPITAL DISTRICT NORTH AND WEST. A COLD
FRONT WILL SLOWLY APPROACH FROM THE GREAT LAKES REGION AND MIDWEST
WEDNESDAY INTO THURSDAY WITH A GREATER THREAT OF SHOWERS AND
THUNDERSTORMS INCLUDING SOME LOCALLY HEAVY RAINFALL FOR EASTERN NEW
YORK AND WESTERN NEW ENGLAND THAT MAY CONTINUE UNTIL FRIDAY MORNING.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 128 PM EDT...A WEAK SFC WAVE CONTINUES TO MOVE ALONG A COLD
FRONT NEAR THE NY/CANADIAN BODER THAT EXTENDS EASTWARD INTO MAINE.
A WEAK SFC TROUGH OR WINDSHIFT BOUNDARY WITH THE WEAK DISTURBANCE
MOVING ALONG THE FRONT WILL FOCUS SOME ISOLD-SCT
SHOWERS/THUNDERSTORMS MAINLY FROM THE CAPITAL REGION...SCHOHARIE
VALLEY...AND NRN BERKSHIRES NORTHWARD THIS AFTERNOON.
THE POPS WERE INCREASED TO HIGH CHC VALUES ACROSS THE LAKE GEORGE
REGION INTO THE SRN DACKS...WHERE WE SEE SHOWERS/THUNDERSTORMS
CONTINUE TO POPS UP ON THE REGIONAL/LOCAL RADARS. THE CONVECTIVE
TEMP ON THE 12Z KALY SOUNDING WAS 90F SO EXPECT SOME ISOLD
SHOWER/THUNDERSTORM ACTIVITY A LITTLE FURTHER SOUTH...AS SEEN ON
THE KENX RADAR WITH SOME SHOWERS NEAR EXTREME SRN HERKIMER AND ERN
SCH COUNTY. THE LATEST SPC MESOANALYSIS FROM THE RAPID REFRESH INDICATES
SOME SBCAPE VALUES OF 1000-1500 J/KG OVER PARTS OF THE ALY FCST
AREA...THOUGH THE DEEP SHEAR IS VERY WEAK WITH 20 KTS GRAZING THE
NRN TIER /SRN DACK AND LAKE GEORGE REGION/. ACTIVITY FURTHER SOUTH
IS NOT LIKELY DUE TO THE MID LEVEL CAP AT 675-625 HPA ON THE KALY
SOUNDING. THE ISOLD/SCT SHRAS/TSRAS SHOULD DIMINISH LATE THIS PM
WITH THE DIURNAL HEATING DIMINISHING. THE LATEST HRRR COLUMNAR REF
PRODUCT SUPPORTS THIS TREND.
HUMIDITY LEVELS WILL BE UNCOMFORTABLE THIS AFTERNOON WITH SFC
DEWPTS IN THE M60S TO L70S. HIGHS IN THE U80S TO L90S LOOK ON
TRACK IN MANY OF THE VALLEY AREAS /A FEW M90S NEAR KPOU/...AND
U70S TO M80S OVER THE MTNS. APPARENT TEMPS ARE GENERALLY IN THE
LOWER TO M90S WITH A FEW U90S IN THE MID HUDSON VALLEY.
THE COLD FRONT WILL RETREAT NORTHWARD AS A WARM FRONT TONIGHT. AS
A RESULT EXPECT WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ACROSS
THE NORTHERN THIRD OF THE FA TO DIMINISH OVERNIGHT. ANOTHER WARM
AND MUGGY NIGHT IS EXPECTED. LOWS TONIGHT WILL BE IN THE 60S TO
AROUND 70F.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
FOR WEDNESDAY AND WEDNESDAY NIGHT EXPECT AN INCREASING CHANCE OF
SHOWERS AND THUNDERSTORMS AS THE COLD FRONT MOVES FROM THE CENTRAL GREAT
LAKES WEDNESDAY MORNING INTO NORTHERN NEW YORK AND NORTHERN NEW
ENGLAND LATE WEDNESDAY. THE FRONTAL BOUNDARY WILL STALL ACROSS
EASTERN NEW YORK AND NORTHERN NEW ENGLAND WEDNESDAY NIGHT AS
SEVERAL WAVES OF LOW PRESSURE TRACK NORTHEAST ALONG THE BOUNDARY. PWATS
DURING THIS TIME INCREASE TO 1.75 TO 2+ INCHES...ML MUCAPES
INCREASE TO 500 TO 1000 J/KG WITH DEWPOINTS REMAINING MAINLY IN
THE 60S. AT THIS TIME NOT EXPECTING THE THUNDERSTORMS TO BE
SEVERE. HOWEVER AS WE GET INTO WEDNESDAY AND WEDNESDAY NIGHT HEAVY
DOWNPOURS WILL BE POSSIBLE WITH ANY THUNDERSTORMS ESPECIALLY GIVEN
THE HIGH PWAT VALUES. HIGHS ON WEDNESDAY ARE EXPECTED TO BE IN THE
80S WITH LOWS WEDNESDAY NIGHT IN 60S.
THURSDAY AND THURSDAY NIGHT LOOK WET AS THE SECOND WAVE OF LOW
PRESSURE TRACKS NORTHEAST ALONG THE STALLED FRONTAL BOUNDARY AND A
SECONDARY TROUGH OF LOW PRESSURE MOVES INTO NORTHERN NEW YORK.
PWATS REMAIN BETWEEN 1.5 AND 2 INCHES ON THURSDAY AND GRADUALLY
LOWER THURSDAY NIGHT. THINKING AT THIS TIME IS THAT THE HEAVIEST
RAINFALL WILL BE ACROSS THE SOUTHEASTERN TWO THIRDS OF THE FA ON
THURSDAY AND ACROSS THE SOUTHEASTERN THIRD OF THE FA THURSDAY
NIGHT. TOTAL RAINFALL AMOUNTS COULD EASILY REACH SEVERAL INCHES IN
SOME SPOTS. EXPECT HIGHS ON THURSDAY TO BE IN THE 70S TO LOWER 80S
WITH LOWS THURSDAY NIGHT IN THE MID 50S TO MID 60S.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
A PATTERN CHANGE WILL BE UNDERWAY DURING THIS TIME PERIOD...AS THE
RECENT EASTERN NOAM RIDGE PUSHES FURTHER EAST OFF THE COAST...WHILE
AN UPPER LEVEL TROUGH DEVELOPS ACROSS THE NORTHERN PLAINS/UPPER
GREAT LAKES REGION. MODELS CONTINUE TO EXHIBIT SOME UNCERTAINTY AS
TO HOW THIS PATTERN CHANGE UNFOLDS...WITH THE 00Z/08 GFS AND GEFS
REMAINING SLIGHTLY MORE PROGRESSIVE WITH THE EVOLVING
PATTERN...WHILE THE 00Z/08 ECMWF IS SLOWER AND MORE AMPLIFIED. THIS
DIFFERENCE IS MOST NOTABLE FOR NEXT WEEKEND...AS THE GFS WOULD IMPLY
A QUICKER PASSAGE OF THE UPPER LEVEL TROUGH...ALONG WITH SCATTERED
RAIN SHOWERS FOR SAT...WHILE THE ECMWF WOULD IMPLY ENERGY HOLDING
BACK AND POTENTIALLY CARVING OUT A CLOSED MID LEVEL LOW CENTER WHICH
COULD BRING SHOWERS OR EVEN A WIDESPREAD STEADY RAINFALL FOR NEXT
SAT NT AND SUNDAY...ALONG WITH MUCH BELOW NORMAL TEMPS. TRENDS
OVERALL DO SEEM TO BE TOWARD A MORE PESSIMISTIC FORECAST...SO HAVE
INCREASED THE CHANCES FOR SHOWERS FROM SAT AFTERNOON INTO SUNDAY
ACROSS THE REGION.
HERE ARE SOME SPECIFICS...
FRI-SAT...SHOWERS MAY BE SLOW TO EXIT FRI MORNING...ESP FOR AREAS E
OF THE HUDSON RIVER...AS THE MID/UPPER LEVEL FLOW REMAINS SOMEWHAT
SOUTHWEST WITH THE RIDGE PERSISTING OFF THE EAST COAST...AND ALSO
THE PROXIMITY OF THE RIGHT ENTRANCE REGION TO AN UPPER LEVEL JET MAX
TRANSLATING ACROSS SOUTHEAST CANADA. IN FACT...THE LATEST 00Z/08
ECMWF SUGGESTS A WAVE DEVELOPS LONG THE DEPARTING FRONTAL
ZONE...ALLOWING FOR SHOWERS TO LINGER WELL INTO FRI MORNING FOR
AREAS NEAR AND EAST OF THE HUDSON RIVER. WILL THEREFORE KEEP CHC
POPS FOR MOST AREAS NEAR AND ESP E OF THE HUDSON RIVER IN THE
MORNING WITH SLIGHT CHC FURTHER N AND W...THEN DECREASE FROM W TO E
IN THE AFTERNOON. WILL THEN KEEP CONDITIONS MAINLY DRY FOR FRI
NT/SAT AM...WITH INCREASING CHANCES FOR SHOWERS SATURDAY AFTERNOON
FROM W TO E. AS FOR TEMPS...A COOLING TREND WILL BE UNDERWAY...WITH
MAX TEMPS GENERALLY IN THE LOWER/MID 70S FOR VALLEYS...AND 60S
ACROSS HIGHER TERRAIN. HOWEVER...EVEN COOLER MAX TEMPS COULD OCCUR
SHOULD CLOUDS/SHOWERS PERSIST LONGER THAN CURRENTLY EXPECTED FOR
FRI. FRI NT/SAT AM MINS SHOULD FALL INTO THE 50S FOR MOST
AREAS...WITH SOME 40S POSSIBLE ACROSS HIGHER ELEVATIONS WITHIN THE
SOUTHERN ADIRONDACKS.
SAT NT-SUN...MODELS CONTINUE TO TREND WETTER FOR THIS PERIOD...WITH
THE 00Z/08 ECMWF MOST AGGRESSIVE WITH A POSSIBLE STEADY RAINFALL AND
VERY COOL TEMPS. WILL KEEP CHC POPS FOR ALL AREAS DURING THIS
PERIOD. FOR TEMPS...EXPECT MAXES TO REACH 70-75 IN VALLEYS AND 60S
ACROSS HIGHER ELEVATIONS. HOWEVER...SHOULD A WIDESPREAD STEADY RAIN
OCCUR...MOST AREAS WOULD LIKELY REMAIN IN THE 60S ON SUNDAY...WITH
EVEN SOME UPPER 50S POSSIBLE IN HIGHER ELEVATIONS. SUN AM MINS
SHOULD MAINLY BE IN THE 50S.
SUN NT-MON...SOME SHOWERS MAY LINGER INTO SUN NT/MON AM...ESP ACROSS
WESTERN NEW ENGLAND...THEN TRENDING DRIER BY LATE MON. SUN NT/MON AM
MINS SHOULD MAINLY FALL INTO THE 50S...ALTHOUGH SOME 40S COULD OCCUR
IN HIGHER TERRAIN. MON MAX TEMPS SHOULD REACH THE LOWER/MID 70S IN
VALLEYS...AND 60S ACROSS HIGHER ELEVATIONS.
&&
.AVIATION /17Z TUESDAY THROUGH SATURDAY/...
HIGH PRESSURE WILL REMAIN OFF THE MID ATLANTIC COAST INTO THIS
EVENING. A WEAK COLD FRONT WILL APPROACH FROM THE NORTH THIS
AFTERNOON AND EVENING...BEFORE RETREATING BACK NORTHWARD TONIGHT.
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS ASSOCIATED WITH AN
APPROACHING WEAK COLD FRONT ARE AROUND KGFL THIS AFTERNOON...BETWEEN
ROUGHLY 18Z-22Z/TUE. A VCSH HAS BEEN INDICATED IN THE KGFL TAF FOR
THIS POSSIBILITY. AT KALB...CAN NOT COMPLETELY RULE OUT ISOLATED
SHOWERS/THUNDERSTORMS BETWEEN 18Z-22Z/TUE...SO ADDED VCSH.
ELSEWHERE...GENERALLY DRY CONDITIONS ARE EXPECTED THROUGH THIS
EVENING.
FOR TONIGHT...SOME PATCHY FOG AND/OR LOW CLOUDS MAY DEVELOP AT
KPSF...AND PERHAPS KGFL AFTER 05Z/WED. THE BEST CHANCE FOR IFR
CONDITIONS WILL BE KPSF...WHICH HAS BEEN INCLUDED IN CURRENT TAFS.
PATCHY LOW CLOUDS COULD DEVELOP AT KPOU TOWARD 12Z/WED WITH MVFR
CIGS. AFTER 13Z...ANY FOG AND/OR LOW CLOUDS SHOULD BURN OFF AND VFR
CONDITIONS SHOULD PREVAIL.
LIGHT SOUTHWEST TO WEST WINDS AROUND 5-10 KT THIS AFTERNOON. THERE
COULD BE SOME SLIGHTLY STRONGER GUSTS UP TO 15 KT THIS AFTERNOON.
WINDS WILL THEN BECOME LIGHT/VARIABLE TOWARD AND AFTER
SUNSET...ALTHOUGH A SOUTH WIND MAY PERSIST AND/OR REDEVELOP AT KALB
OVERNIGHT AT 5-10 KT. SOUTH TO SOUTHWEST WINDS AT LESS THAN 10 KT
DEVELOPING WEDNESDAY MORNING.
OUTLOOK...
WEDNESDAY NIGHT: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
THURSDAY: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
THURSDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
FRIDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
FRIDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
SATURDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
&&
.FIRE WEATHER...
HIGH PRESSURE NEAR THE MID ATLANTIC REGION WILL CONTINUE TO
PROVIDE UNSEASONABLY HOT WEATHER UNTIL WEDNESDAY. A WEAK
DISTURBANCE TODAY WILL BRING ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS FROM THE CAPITAL DISTRICT NORTH AND WEST. A COLD
FRONT WILL SLOWLY APPROACH FROM THE GREAT LAKES REGION AND MIDWEST
WEDNESDAY INTO THURSDAY WITH A GREATER THREAT OF SHOWERS AND
THUNDERSTORMS INCLUDING SOME LOCALLY HEAVY RAINFALL FOR EASTERN
NEW YORK AND WESTERN NEW ENGLAND.
RELATIVE HUMIDITIES WILL DROP TO 35 TO 65 PERCENT THIS
AFTERNOON...RECOVER TO 70 TO 100 PERCENT TONIGHT...AND DROP TO 35
TO 60 PERCENT ON WEDNESDAY.
WINDS TODAY WILL BE SOUTHWEST TO WEST AT 5 TO 10 MPH...LIGHT AND
VARIABLE TONIGHT...AND SOUTH TO SOUTHWEST AT 5 TO 10 MPH ON
WEDNESDAY.
&&
.HYDROLOGY...
NO WIDESPREAD HYDRO PROBLEMS ARE EXPECTED THROUGH WEDNESDAY. THE
END OF THE WEEK LOOKS VERY WET AND EXCESSIVE RAINFALL IS POSSIBLE
SO THE THREAT OF FLOODING WILL BE INCREASING.
A HOT AND HUMID AIR MASS WILL BE OVER THE REGION INTO THE MID
WEEK. SOME ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE
POSSIBLE MAINLY FROM THE GREATER CAPITAL DISTRICT NORTH AND WEST
THROUGH WEDNESDAY.
A MORE WIDESPREAD CHANCE OF SHOWERS AND THUNDERSTORMS WILL OCCUR
AHEAD OF A COLD FRONT WEDNESDAY NIGHT THROUGH THURSDAY NIGHT. THE
COLD FRONT IS EXPECTED TO SLOWLY MOVE ACROSS THE REGION THURSDAY
NIGHT. GUIDANCE INDICATES PWATS SHOULD RISE TO 1.5 TO 2 INCHES
AHEAD OF THE BOUNDARY...SO HEAVY DOWNPOURS ARE TO BE EXPECTED WITH
SOME THUNDERSTORMS. SOME POOR DRAINAGE FLOODING...AND PONDING OF
WATER ON ROADWAYS WILL BE POSSIBLE AND HEAVY RAINFALL MAY LINGER
INTO FRIDAY AS A WAVE OF LOW PRESSURE DEVELOPS ALONG THE FRONT AND
TRACKS NORTHEASTWARD. SEVERAL INCHES OF RAIN TOTAL ARE POSSIBLE IN
SOME SPOTS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.CLIMATE...
RECORD HIGH TEMPERATURES WERE BROKEN AT POUGHKEEPSIE AND GLENS FALLS
MONDAY SEPTEMBER 7TH.
POUGHKEEPSIE: HIGH 95 DEGREES BREAKING THE OLD RECORD OF 90 DEGREES
SET IN 2001. NOTE...RECORDS FOR POUGHKEEPSIE DATE BACK TO
1949...HOWEVER DATA IS MISSING FROM JANUARY 1993 THROUGH JULY
2000.
GLENS FALLS: HIGH 92 DEGREES BREAKING THE OLD RECORD OF 89 DEGREES
SET IN 2007. NOTE...RECORDS FOR GLENS FALLS DATE BACK TO 1949.
AT ALBANY THE HIGH WAS 92 DEGREES. THIS FALLS SHORT OF THE RECORD
FOR SEPTEMBER 7TH OF 96 DEGREES SET BACK IN 1945. NOTE...RECORDS
FOR ALBANY DATE BACK TO 1874.
RECORD HIGH TEMPERATURES...
SEPTEMBER 8TH...
ALBANY: 93 DEGREES 1945
GLENS FALLS: 90 DEGREES 1959
POUGHKEEPSIE: 92 DEGREES 2007
SEPTEMBER 9TH...
ALBANY: 94 DEGREES 1959
GLENS FALLS: 92 DEGREES 1959
POUGHKEEPSIE: 91 DEGREES 1989
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...11/WASULA
NEAR TERM...11/WASULA
SHORT TERM...11
LONG TERM...KL
AVIATION...KL
FIRE WEATHER...11
HYDROLOGY...11/WASULA
CLIMATE...IAA
AREA FORECAST DISCUSSION
NWS MIAMI FL
146 PM EDT TUE SEP 8 2015
.AVIATION...
CONVECTION HAS BEEN VERY SLOW TO GET GOING AND THUS FAR HAS BEEN
WELL INLAND FROM THE TERMINALS AS THE EAST COAST SEA BREEZE HAS
PUSHED INLAND AIDED FROM EARLIER OUTFLOW BOUNDARIES. HOWEVER,
SOUTH-SOUTHWEST STEERING FLOW COULD EASILY MOVE CELLS BACK CLOSER
TO THE EAST COAST AND THE HRRR HINTS AT THIS AFT 19-20Z SO A
LITTLE HESITANT TO REMOVE FROM THE FORECAST. MOST ACTIVITY WILL
MORE LIKELY BE INLAND LATER THIS AFTERNOON. SURFACE WIND WILL ONCE
AGAIN BECOME L/V AFT 00Z WITH VFR CONDITIONS EXPECTED OVERNIGHT.
KOB
&&
.PREV DISCUSSION... /ISSUED 1019 AM EDT TUE SEP 8 2015/
UPDATE...
MID LEVEL TROUGH CONTINUES TO DRIFT NORTHWEST ACROSS THE NORTHEAST
GULF OF MEXICO WITH ATLANTIC RIDGE BUILDING BACK TO THE WEST OVER
SOUTH FLORIDA. THIS HAS RESULTED IN A CONTINUATION OF DEEP
SOUTHERLY MOIST AIR BUT WITH SLIGHT WARMING ALOFT. THEREFORE,
ACTIVITY WILL NOT BE AS ROBUST AS YESTERDAY BUT COULD STILL GET
TORRENTIAL DOWNPOURS ESPECIALLY WHEREVER CONVERGENT BOUNDARIES MAY
SET UP. SO WILL LEAVE MENTION OF FLOODING POTENTIAL IN THE HWO BUT
WILL REMOVE STRONG WIND GUSTS DUE TO A LACK OF ANY DISCERNIBLE DRY
LAYERS OBSERVED FROM THE 12Z MFL SOUNDING.
KOB
PREV DISCUSSION... /ISSUED 736 AM EDT TUE SEP 8 2015/
AVIATION...
A DEEP SOUTHERLY FLOW OF TROPICAL AIR WILL INFLUENCE SOUTH FLORIDA
THROUGH THE FORECAST PERIOD WITH SEA BREEZES DEVELOPING ALONG BOTH
COASTS. THUNDERSTORMS WILL NOT BE QUITE AS ACTIVE AS YESTERDAY
WITH SOME WARMING ALOFT AND WILL MOSTLY MOVE INLAND AWAY FROM THE
TERMINALS. THUS, HAVE KEPT VCTS IN FOR ALL TAF SITES FOR THE LATE
MORNING AND EARLY AFTERNOON.
KOB
PREV DISCUSSION... /ISSUED 306 AM EDT TUE SEP 8 2015/
LATE SUMMER TIME WEATHER PATTERN CONTINUES ACROSS SOUTH FLORIDA
THIS WEEK...
SHORT TERM...
LOW PRESSURE OVER THE NORTHEAST GULF OF MEXICO WILL CONTINUE TO
MOVE NORTHWARD TODAY AND DISSIPATE OVER THE SOUTHEASTERN UNITED
STATES TONIGHT ALLOWING FOR HIGH PRESSURE TO BUILD INTO THE
FLORIDA PENINSULA FROM THE WESTERN ATLANTIC WATERS. THIS WILL
ALLOW FOR THE WIND FLOW OVER SOUTH FLORIDA TO BE SOUTH/SOUTHEAST
AND ALLOW FOR THE SEA BREEZES TO DEVELOP AND PUSH INLAND TODAY.
THEREFORE...THE BEST COVERAGE OF SHOWERS AND THUNDERSTORMS TODAY
WILL BE OVER THE INTERIOR AREAS OF SOUTH FLORIDA.
THE HIGH WILL REMAIN OVER THE WESTERN ATLANTIC WATERS EXTENDING
INTO CENTRAL FLORIDA FOR THE MIDDLE TO END OF THIS WEEK.
THIS WILL KEEP SOUTH FLORIDA IN A EAST TO SOUTHEAST WIND FLOW
FOCUSING THE SHOWERS AND THUNDERSTORM ACTIVITY OVER THE INTERIOR
AND WEST COAST METRO AREAS EACH DAY. THEREFORE...THE HIGHEST POPS
WILL BE OVER THE INTERIOR AND WEST COAST METRO AREAS EACH DAY THIS
WEEK.
LONG TERM...
THE LONG RANGE MODELS ARE SHOWING A COLD FRONT TO MOVE SOUTHWARD
INTO THE SOUTHEAST UNITED STATES THIS WEEKEND AND STALL OUT.
THIS WILL PUSH THE HIGH SOUTHWARD INTO SOUTH FLORIDA THIS WEEKEND
ALLOWING FOR THE WIND FLOW TO BECOME MORE SOUTHERLY ALONG WITH
MORE DEEPER TROPICAL MOISTURE WORKING INTO THE AREA FROM THE
SOUTH. THEREFORE...THE HIGHEST POPS WILL SHIFT TO THE NORTHERN
AREAS OF SOUTH FLORIDA THIS WEEKEND BUT ALL OF SOUTH FLORIDA
SHOULD SEE SCATTERED COVERAGE IN POPS.
MARINE...
THE WINDS WILL BE SOUTH TO SOUTHEAST TODAY BEFORE SWINGING MORE
TO THE SOUTHEAST DIRECTION TONIGHT THROUGH REST OF THE WEEK.
THE WIND SPEEDS WILL BE LESS THAN 10 KNOTS TODAY THROUGH REST OF
THE WEEK. THIS WILL KEEP THE SEAS AT 2 FEET OR LESS IN BOTH THE
ATLANTIC AND GULF WATERS OF SOUTH FLORIDA THROUGH THE WEEK.
THEREFORE...BOATING CONDITIONS SHOULD BE GOOD ACROSS SOUTH FLORIDA
WATERS OUTSIDE OF ANY SHOWERS OR THUNDERSTORMS.
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
354 PM MDT TUE SEP 8 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 222 PM MDT TUE SEP 8 2015
WV IMAGERY AND RAP H5 ANALYSIS SHOWS NW FLOW ACROSS CENTRAL ROCKIES
AND OVER OUR CWA ON WESTERN EXTENT OF LARGE SCALE TROUGH. AXIS OF
SUBSIDENCE IS CURRENTLY IN PLACE AS A SHORTWAVE TROUGH IS MOVING
ACROSS CENTRAL KANSAS. AT THE SURFACE HIGH PRESSURE IS BUILDING INTO
OUR CWA FROM THE NORTHERN PLAINS WITH A COLD FRONT THAT MOVED
THROUGH OUR CWA EARLY THIS MORNING EXTENDING FROM NORTHEAST KANSAS
THROUGH SOUTH CENTRAL KANSAS.
TONIGHT...DRY CONDITIONS SHOULD PERSIST THROUGH THE OVERNIGHT PERIOD
WITH SUBSIDENCE PERSISTING THROUGH MOST OF THE NIGHT...AND DEEP DRY
AIR MASS IN PLACE. EARLY IN THE EVENING STEEP LAPSE RATES LEE TROUGH
REBUILDS ALONG KS/CO BORDER OVERNIGHT WITH SOUTHERLY FLOW BRINING
HIGH BL MOISTURE IN PLACE. TREND IN GUIDANCE HAS BEEN TO TO SHOW
BETTER MIXING AND BL RH STAYING UP LIMITING FOG POTENTIAL. NAM AND
RAP DO STILL SHOW SOME REDUCED VISIBILITIES AND I FELT COMFORTABLE
KEEPING MENTION IN FORECAST FOR NOW.
WEDNESDAY...A QUICK MOVING/WEAK SHORTWAVE TROUGH WILL ROTATE THROUGH
NW FLOW JUST NORTH OF OUR CWA. DRY LAYER IN PLACE LOWERS OVERALL
CONFIDENCE IN COVERAGE...HOWEVER GUIDANCE IS SHOWING INITIATION
EITHER UPSTREAM OR ALONG SURFACE TROUGH AND TRACKING EAST ACROSS THE
NORTHERN HALF OF OUR CWA. IF A CELL WERE TO DEVELOP ML CAPE VALUES
AROUND 2000 J/KG AND EFFECTIVE SHEAR VALUES AROUND 35KT COULD
SUPPORT A LIMITED SEVERE THREAT. IM JUST NOT SURE IF ANYTHING WILL
EVEN DEVELOP CONSIDERING THE DRY AIR MASS IN PLACE. I KEPT SLIGHT
CHANCE POPS IN THE AFTERNOON...COVERING POTENTIAL.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 255 PM MDT TUE SEP 8 2015
SEVERAL SHORT WAVE TROUGHS MOVE ACROSS THE CENTRAL HIGH PLAINS
REGION WEDNESDAY NIGHT...THURSDAY NIGHT...AND FRIDAY EVENING. THE
UPPER PATTERN BECOMES MORE AMPLIFIED AS THE SHORT WAVE TROUGHS
DIVE INTO THE BASE OF THE MAIN UPPER TROUGH POSITIONED OVER THE
MISSISSIPPI VALLEY REGION AS THE UPPER RIDGE AMPLIFIES OVER THE
WESTERN UNITED STATES THURSDAY THROUGH FRIDAY NIGHT AND
TRANSITIONS EASTWARD OVER THE ROCKIES AND HIGH PLAINS SATURDAY
NIGHT.
WITH A SURFACE TROUGH/FRONTAL BOUNDARY REMAINING IN THE VICINITY
OF THE FORECAST AREA THESE SHORT WAVE TROUGHS TRANSITIONING THE
REGION WILL HELP ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
DEVELOP EACH DAY FROM LATE WEDNESDAY THROUGH EARLY FRIDAY. BY LATE
FRIDAY THE FRONTAL BOUNDARY HAS PUSHED SOUTH OF THE REGION AND
SURFACE HIGH PRESSURE MOVES INTO THE AREA. TEMPERATURES WILL WARM
THROUGH THURSDAY AHEAD OF THE FRONT WITH HIGH TEMPERATURES ONLY
EXPECTED TO REACH IN TO THE 70S ON FRIDAY. TEMPERATURES WILL
REBOUND QUICKLY THROUGH THE WEEKEND AND INTO NEXT WEEK AS
SOUTHERLY NEAR SURFACE FLOW RETURNS AND THE REGION REMAINS UNDER
WEAK RIDGING THROUGH THE WEEKEND AS THE UPPER PATTERN UNDERGOES A
TRANSITION TO A RIDGE OVER THE EASTERN HALF OF THE UNITED STATES
WHILE THE NEXT SIGNIFICANT LONG WAVE TROUGH DEEPENS OVER THE
WESTERN UNITES STATES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1122 AM MDT TUE SEP 8 2015
MVFR CIGS AROUND 1500 FT ARE STILL LIKELY TO ADVECT ACROSS THE
KMCK DURING THE EARLY PART OF THE TAF PERIOD WITH VIS SATELLITE
AND UPSTREAM OBS SHOWING THIS STRATUS FIELD MOVING SE WITH LOWEST
OBS BELOW 1000 FT. SHORT RANGE GUIDANCE INDICATES THIS SHOULD
CONTINUE TO DISSIPATE WITH DAYTIME HEATING...SO I WAS NOT
CONFIDENT ENOUGH TO CARRY MENTION OF MORE THAN TEMPO MVFR. VFR
WILL PREVAIL AT KGLD THROUGH THE FIRST 12 HR OF THE TAF PERIOD.
AFTER 06Z TONIGHT SOUTHERLY FLOW WILL BRING INCREASING
MOISTURE ONCE AGAIN TO THE REGION AND THE POSSIBILITY FOR
FOG/STRATUS. STRONGEST SIGNAL IN GUIDANCE IS IN SW NEBRASKA AND
SOUTH OF INTERSTATE 70...HOWEVER BOTH TERMINALS WILL LIKELY SEE A
PERIOD OF AT LEAST MVFR CONDITIONS AROUND SUNRISE. CONFIDENCE IS
TOO LOW TO INCLUDE LOWER CONDITIONS DUE TO A LACK OF
CONSENSUS/CONSISTENCY IN LOCATION OF BEST MOISTURE/LOWEST MIXING.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...LOCKHART
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
222 PM MDT TUE SEP 8 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 222 PM MDT TUE SEP 8 2015
WV IMAGERY AND RAP H5 ANALYSIS SHOWS NW FLOW ACROSS CENTRAL ROCKIES
AND OVER OUR CWA ON WESTERN EXTENT OF LARGE SCALE TROUGH. AXIS OF
SUBSIDENCE IS CURRENTLY IN PLACE AS A SHORTWAVE TROUGH IS MOVING
ACROSS CENTRAL KANSAS. AT THE SURFACE HIGH PRESSURE IS BUILDING INTO
OUR CWA FROM THE NORTHERN PLAINS WITH A COLD FRONT THAT MOVED
THROUGH OUR CWA EARLY THIS MORNING EXTENDING FROM NORTHEAST KANSAS
THROUGH SOUTH CENTRAL KANSAS.
TONIGHT...DRY CONDITIONS SHOULD PERSIST THROUGH THE OVERNIGHT PERIOD
WITH SUBSIDENCE PERSISTING THROUGH MOST OF THE NIGHT...AND DEEP DRY
AIR MASS IN PLACE. EARLY IN THE EVENING STEEP LAPSE RATES LEE TROUGH
REBUILDS ALONG KS/CO BORDER OVERNIGHT WITH SOUTHERLY FLOW BRINING
HIGH BL MOISTURE IN PLACE. TREND IN GUIDANCE HAS BEEN TO TO SHOW
BETTER MIXING AND BL RH STAYING UP LIMITING FOG POTENTIAL. NAM AND
RAP DO STILL SHOW SOME REDUCED VISIBILITIES AND I FELT COMFORTABLE
KEEPING MENTION IN FORECAST FOR NOW.
WEDNESDAY...A QUICK MOVING/WEAK SHORTWAVE TROUGH WILL ROTATE THROUGH
NW FLOW JUST NORTH OF OUR CWA. DRY LAYER IN PLACE LOWERS OVERALL
CONFIDENCE IN COVERAGE...HOWEVER GUIDANCE IS SHOWING INITIATION
EITHER UPSTREAM OR ALONG SURFACE TROUGH AND TRACKING EAST ACROSS THE
NORTHERN HALF OF OUR CWA. IF A CELL WERE TO DEVELOP ML CAPE VALUES
AROUND 2000 J/KG AND EFFECTIVE SHEAR VALUES AROUND 35KT COULD
SUPPORT A LIMITED SEVERE THREAT. IM JUST NOT SURE IF ANYTHING WILL
EVEN DEVELOP CONSIDERING THE DRY AIR MASS IN PLACE. I KEPT SLIGHT
CHANCE POPS IN THE AFTERNOON...COVERING POTENTIAL.
.LONG TERM...(FRIDAY THROUGH MONDAY)
ISSUED AT 219 AM MDT TUE SEP 8 2015
BOTH THE GFS AND EUROPEAN HAVE A SIMILAR
UPPER LEVEL FLOW PATTERN WITH A TROUGH SITTING OVER THE EASTERN
PORTIONS OF THE US AND A RIDGE SITTING OVER THE WESTERN US. THIS
PATTERN STAYS CONSISTENT AND SIMILAR IN BOTH MODELS FRIDAY 12Z
THROUGH SATURDAY 18Z. AFTER THIS TIME THE GFS STARTS TO WEAKEN AND
BREAK UP THE EASTERN TROUGH...THIS CAUSES A CUT OFF LOW TO MOVE INTO
THE SOUTHEASTERN STATES. THE EUROPEAN SHOWS THIS TROUGH TO BE MUCH
STRONGER AND IT HOLDS STEADY AS IT CONTINUES TO MOVE EAST.
FOR SUNDAY INTO MONDAY THE GFS IS SHOWING A ZONAL FLOW PATTERN OVER
THE FAR NORTHERN STATES INTO CANADA WITH A CUT OFF LOW BREAKING OFF
AND MOVING INTO THE NORTHWESTERN STATES. THIS IS NOT THE SAME UPPER
LEVEL FLOW IN THE EUROPEAN. SINCE THE TROUGH IS MUCH STRONGER...THE
RIDGE IN THE WEST IS SHOWING TO BE A LITTLE STRONGER THAN IN THE
GFS. SO THE CUT OFF LOW IN THE NORTHWEST DOES NOT SHOW UP IN THE
EUROPEAN. THIS WILL BE SOMETHING TO KEEP AN EYE ON.
IN GENERAL...BOTH THE GFS AND EUROPEAN KEEP THE RIDGE IN THE WEST
STRONG...WHICH WILL START TO IMPACT THE REGION THIS WEEKEND. THIS
WILL CAUSE DRIER CONDITIONS AND TEMPERATURES WILL INCREASE SLIGHTLY
AS WE PROGRESS INTO EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1122 AM MDT TUE SEP 8 2015
MVFR CIGS AROUND 1500 FT ARE STILL LIKELY TO ADVECT ACROSS THE
KMCK DURING THE EARLY PART OF THE TAF PERIOD WITH VIS SATELLITE
AND UPSTREAM OBS SHOWING THIS STRATUS FIELD MOVING SE WITH LOWEST
OBS BELOW 1000 FT. SHORT RANGE GUIDANCE INDICATES THIS SHOULD
CONTINUE TO DISSIPATE WITH DAYTIME HEATING...SO I WAS NOT
CONFIDENT ENOUGH TO CARRY MENTION OF MORE THAN TEMPO MVFR. VFR
WILL PREVAIL AT KGLD THROUGH THE FIRST 12 HR OF THE TAF PERIOD.
AFTER 06Z TONIGHT SOUTHERLY FLOW WILL BRING INCREASING
MOISTURE ONCE AGAIN TO THE REGION AND THE POSSIBILITY FOR
FOG/STRATUS. STRONGEST SIGNAL IN GUIDANCE IS IN SW NEBRASKA AND
SOUTH OF INTERSTATE 70...HOWEVER BOTH TERMINALS WILL LIKELY SEE A
PERIOD OF AT LEAST MVFR CONDITIONS AROUND SUNRISE. CONFIDENCE IS
TOO LOW TO INCLUDE LOWER CONDITIONS DUE TO A LACK OF
CONSENSUS/CONSISTENCY IN LOCATION OF BEST MOISTURE/LOWEST MIXING.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...CLT
AVIATION...DR
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
237 PM EDT TUE SEP 8 2015
.SYNOPSIS...
RAIN WILL BE LIKELY AS A COLD FRONT APPROACHES ON WEDNESDAY AND
SLOWLY MOVES THROUGH THE AREA ON THURSDAY. THIS WILL BRING TO AN
END OUR PERIOD OF MUCH ABOVE NORMAL TEMPERATURES.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
CUMULUS HAS BEEN DEVELOPING RATHER READILY JUST TO THE NORTH AND
WEST OF THE FORECAST AREA WHERE BOUNDARY LAYER MOISTURE IS
DECIDEDLY HIGHER. THIS IS EVIDENCED BY DEWPOINTS ACROSS WESTERN
AND NORTHERN OHIO NOW RUNNING UP TOWARD AND EVEN ABOVE 70F IN SOME
CASES. AS YOU MOVE EASTWARD TOWARD THE OHIO RIVER AND IN WESTERN
PENNSYLVANIA...LOWER TO MID 60 DEWPOINTS ARE MORE COMMON. A
DISTRIBUTION SIMILAR TO THIS HAS BEEN INDICATED BY THE
HRRR...HOWEVER THE NORMAL OVERLY AGGRESSIVE DRY AIR ENTRAINMENT OF
THE HRRR IS ALSO NOTED...SO WHILE THE DISTRIBUTION OF DEWPOINT
VALUES IS REPRESENTATIVE...THE VALUES FAIL TO BE ACCURATE. THE
LOWERING OF BOUNDARY LAYER MOISTURE OVER PENNSYLVANIA HAS MANAGED
TO ALLOW FOR SLOWER CUMULUS GROWTH...AND THE DRY AIR ALOFT SHOULD
PRECLUDE SHOWER DEVELOPMENT...EVEN WITH AMPLE INSOLATION THROUGH
THE EVENING. THAT SAID...VERY WARM CONDITIONS WILL REMAIN OVER THE
FORECAST AREA WITH WARM ADVECTION CONTINUING INTO TONIGHT AS 850
MB TEMPERATURES RUN UP TOWARD +19C TODAY WITH AT LEAST MODEST
MIXING.
GLOBAL MODEL AND ENSEMBLE SOLUTIONS CONTINUE TO BE FAIRLY SLOW
WITH THE LARGE SCALE EVOLUTION OF THE NEXT SYSTEM THAT WILL IMPACT
THE AREA BEGINNING ON WEDNESDAY. LAYER RH PLOTS REVEAL MUCH OF THE
NIGHT SHOULD REMAIN RATHER CLEAR AFTER WE DECOUPLE THIS EVENING.
THIS WILL AGAIN ALLOW FOR A BIT OF RIVER VALLEY FOG...HOWEVER ITS
EXPANSION AWAY FROM RIVERS SEEMS RATHER UNLIKELY...SO IT WAS NOT
CARRIED IN THE GRIDS. ADDITIONALLY...WITH LITTLE CHANGE IN THE
OVERALL PATTERN FOR TONIGHT RELATIVE TO RECENT NIGHTS...LOW
TEMPERATURES NEAR PERSISTENCE SEEM REASONABLE.
FINALLY ON WEDNESDAY LAYER RH VALUES START TO KICK UPWARD...AS THE
MID-LEVEL FRONTAL BOUNDARY STARTS TO TRUCK EASTWARD OUT OF THE
CENTRAL GREAT LAKES AND TOWARD THE UPPER OHIO VALLEY. INSTABILITY
AHEAD OF THE FRONT IS NOT OVERLY IMPRESSIVE AS NO MODEL EVEN
ECLIPSES 1000 J/KG OF CAPE AND SHEAR IS LIKEWISE MEAGER...SO WHILE
SOME THUNDER DEVELOPMENT IS LIKELY...ORGANIZED SEVERE WEATHER IS
NOT. THAT SAID...DIFFERENTIAL PVA ALONG SAID FRONT OUT AHEAD OF
THE RIGHT ENTRANCE REGION OF THE UPPER JET SHOULD GIVE ENOUGH OF A
SYNOPTIC SCALE KICK TO ALLOW FOR THOSE <1000 J/KG TO BE REALIZED.
AS A RESULT...POPS WERE CONTINUED AS LIKELY THROUGH THE AFTERNOON
HOURS. HOWEVER...BEFORE PRECIPITATION ENVELOPS THE
AREA...TEMPERATURES SHOULD GET A NICE KICK NORTHWARD WITH ANOTHER
DAY OF SOLIDLY ABOVE NORMAL TEMPERATURES BEFORE THE FRONTAL
ARRIVAL. FRIES
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
THE WEAKENING FRONTAL BOUNDARY WILL LOSE ITS FORWARD PROGRESS AS
IT REACHES THE FORECAST AREA OVERNIGHT WEDNESDAY AND EARLY
THURSDAY. THIS WILL ALLOW A SHORTWAVE TO RIDE NORTHWARD ALONG THE
FRONT THURSDAY MORNING...WITH HINTS TO THIS DEVELOPMENT ON ALL OF
THE LATEST MODEL GUIDANCE. THUS...FORECAST WAS UPDATED TO CARRY
LIKELY POPS THROUGH THE FIRST HALF OF THURSDAY BEFORE THE WAVE AND
BOUNDARY PUSH EASTWARD. CONSIDERING THE OVERNIGHT TIMING FOR THE
FRONT...WILL MENTION THE CHANCE FOR THUNDER...BUT INSTABILITY IS
RATHER NEGLIGIBLE. TEMPERATURES SHOULD BEGIN TO FALL BACK TOWARD
SEASONAL VALUES ONCE THIS FRONT HAS PASSED...BUT THE NOTICEABLY
COOLER AIR WILL NOT MAKE IT UNTIL THE SECONDARY FRONT AND
DEEPENING UPPER TROUGH APPROACHES FOR THE WEEKEND.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
BROAD UPPER LEVEL TROUGHING IS FORECAST TO DEVELOP OVER THE EASTERN
CONUS FOR THE LONG TERM PERIOD...LEADING TO COOLER TEMPERATURES AND
LOW PRECIP CHANCES. EXTENDED GRIDS WERE CONSTRUCTED CLOSE TO WPC
GUIDANCE.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
VFR CONDITIONS ARE LIKELY TO CONTINUE THROUGH THE AFTERNOON AND
INTO THE MAJORITY OF THE OVERNIGHT WITH LIGHT SOUTHWESTERLY WINDS
BECOMING CALM. CLOUDS WILL INCREASE FROM W-E ON WEDNESDAY MORNING
IN ADVANCE OF THE NEXT SYSTEM TO CROSS THE AREA. SHOWERS AND
THUNDERSTORMS WILL BECOMING LIKELY BY AFTERNOON...LIKELY CAUSING
LOCAL RESTRICTIONS JUST AFTER THE END OF THE TAF VALID PERIOD.
FRIES
OUTLOOK...WEDNESDAY THROUGH SATURDAY...
RESTRICTIONS WILL BECOME LIKELY WITH THE APPROACH OF A COLD FRONT
ON WEDNESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
139 PM EDT TUE SEP 8 2015
.SYNOPSIS...
RAIN WILL BE LIKELY AS A COLD FRONT APPROACHES ON WEDNESDAY AND
SLOWLY MOVES THROUGH THE AREA ON THURSDAY. THIS WILL BRING TO AN
END OUR PERIOD OF MUCH ABOVE NORMAL TEMPERATURES.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
CUMULUS HAS BEEN DEVELOPING RATHER READILY JUST TO THE NORTH AND
WEST OF THE FORECAST AREA WHERE BOUNDARY LAYER MOISTURE IS
DECIDEDLY HIGHER. THIS IS EVIDENCED BY DEWPOINTS ACROSS WESTERN
AND NORTHERN OHIO NOW RUNNING UP TOWARD AND EVEN ABOVE 70F IN SOME
CASES. AS YOU MOVE EASTWARD TOWARD THE OHIO RIVER AND IN WESTERN
PENNSYLVANIA...LOWER TO MID 60 DEWPOINTS ARE MORE COMMON. A
DISTRIBUTION SIMILAR TO THIS HAS BEEN INDICATED BY THE
HRRR...HOWEVER THE NORMAL OVERLY AGGRESSIVE DRY AIR ENTRAINMENT OF
THE HRRR IS ALSO NOTED...SO WHILE THE DISTRIBUTION OF DEWPOINT
VALUES IS REPRESENTATIVE...THE VALUES FAIL TO BE ACCURATE. THE
LOWERING OF BOUNDARY LAYER MOISTURE OVER PENNSYLVANIA HAS MANAGED
TO ALLOW FOR SLOWER CUMULUS GROWTH...AND THE DRY AIR ALOFT SHOULD
PRECLUDE SHOWER DEVELOPMENT...EVEN WITH AMPLE INSOLATION THROUGH
THE EVENING. THAT SAID...VERY WARM CONDITIONS WILL REMAIN OVER THE
FORECAST AREA WITH WARM ADVECTION CONTINUING INTO TONIGHT AS 850
MB TEMPERATURES RUN UP TOWARD +19C TODAY WITH AT LEAST MODEST
MIXING.
GLOBAL MODEL AND ENSEMBLE SOLUTIONS CONTINUE TO BE FAIRLY SLOW
WITH THE LARGE SCALE EVOLUTION OF THE NEXT SYSTEM THAT WILL IMPACT
THE AREA BEGINNING ON WEDNESDAY. LAYER RH PLOTS REVEAL MUCH OF THE
NIGHT SHOULD REMAIN RATHER CLEAR AFTER WE DECOUPLE THIS EVENING.
THIS WILL AGAIN ALLOW FOR A BIT OF RIVER VALLEY FOG...HOWEVER ITS
EXPANSION AWAY FROM RIVERS SEEMS RATHER UNLIKELY...SO IT WAS NOT
CARRIED IN THE GRIDS. ADDITIONALLY...WITH LITTLE CHANGE IN THE
OVERALL PATTERN FOR TONIGHT RELATIVE TO RECENT NIGHTS...LOW
TEMPERATURES NEAR PERSISTENCE SEEM REASONABLE.
FINALLY ON WEDNESDAY LAYER RH VALUES START TO KICK UPWARD...AS THE
MID-LEVEL FRONTAL BOUNDARY STARTS TO TRUCK EASTWARD OUT OF THE
CENTRAL GREAT LAKES AND TOWARD THE UPPER OHIO VALLEY. INSTABILITY
AHEAD OF THE FRONT IS NOT OVERLY IMPRESSIVE AS NO MODEL EVEN
ECLIPSES 1000 J/KG OF CAPE AND SHEAR IS LIKEWISE MEAGER...SO WHILE
SOME THUNDER DEVELOPMENT IS LIKELY...ORGANIZED SEVERE WEATHER IS
NOT. THAT SAID...DIFFERENTIAL PVA ALONG SAID FRONT OUT AHEAD OF
THE RIGHT ENTRANCE REGION OF THE UPPER JET SHOULD GIVE ENOUGH OF A
SYNOPTIC SCALE KICK TO ALLOW FOR THOSE <1000 J/KG TO BE REALIZED.
AS A RESULT...POPS WERE CONTINUED AS LIKELY THROUGH THE AFTERNOON
HOURS. HOWEVER...BEFORE PRECIPITATION ENVELOPS THE
AREA...TEMPERATURES SHOULD GET A NICE KICK NORTHWARD WITH ANOTHER
DAY OF SOLIDLY ABOVE NORMAL TEMPERATURES BEFORE THE FRONTAL
ARRIVAL. FRIES
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY/...
A WEAKENING WIND FIELD IN THE WAKE OF AN EXITING JET
STREAK...WHICH IS PROGGED TO TAIL OFF ACROSS THE WESTERN GREAT
LAKES...SHOULD...ALONG WITH POTENTIAL SHORTWAVE PROGRESSION ALONG
THE FRONT...LIMIT DECISIVE PASSAGE UNTIL THURSDAY.
NEVERTHELESS...WITH WEAKENING UPPER SUPPORT AND FADING
INSTABILITY...HAVE TAPERED POPS DOWNWARD ON WEDNESDAY NIGHT...AND
CONTINUED THE TREND THROUGH THURSDAY AS PER A SPLIT OF GFS AND NAM
DEPICTIONS OF FRONTAL AND MID LEVEL TROUGH PROGRESS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
BROAD UPPER LEVEL TROUGHING IS FORECAST TO DEVELOP OVER THE EASTERN
CONUS FOR THE LONG TERM PERIOD...LEADING TO COOLER TEMPERATURES AND
LOW PRECIP CHANCES. EXTENDED GRIDS WERE CONSTRUCTED CLOSE TO WPC
GUIDANCE.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
VFR CONDITIONS ARE LIKELY TO CONTINUE THROUGH THE AFTERNOON AND
INTO THE MAJORITY OF THE OVERNIGHT WITH LIGHT SOUTHWESTERLY WINDS
BECOMING CALM. CLOUDS WILL INCREASE FROM W-E ON WEDNESDAY MORNING
IN ADVANCE OF THE NEXT SYSTEM TO CROSS THE AREA. SHOWERS AND
THUNDERSTORMS WILL BECOMING LIKELY BY AFTERNOON...LIKELY CAUSING
LOCAL RESTRICTIONS JUST AFTER THE END OF THE TAF VALID PERIOD.
FRIES
OUTLOOK...WEDNESDAY THROUGH SATURDAY... RESTRICTIONS
WILL BECOME LIKELY WITH THE APPROACH OF A COLD FRONT ON WEDNESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
418 PM EDT TUE SEP 8 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 417 PM EDT TUE SEP 8 2015
WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A MID/UPPER LEVEL LOW
SPINNING OVER MANITOBA. ONE SHORTWAVE IS LIFTING NE ACROSS NRN
ONTARIO TO THE N OF LAKE OF THE WOODS. TAIL END OF THAT WAVE IS
GENERATING SHRA/TSRA N OF THE MN/ONTARIO BORDER. CLOSER TO HOME...
SHORTWAVE THAT LIFTED ACROSS WI TOWARD ERN UPPER MI BROUGHT
WIDESPREAD SHRA/ISOLD TSTMS ACROSS ALL BUT FAR WRN UPPER MI TODAY.
THAT ACTIVITY IS MOVING OUT QUICKLY NOW. TO THE W...IT APPEARS THAT
THERE ARE 2 BOUNDARIES THAT STILL NEED TO BE WATCHED FOR NEW
CONVECTIVE DEVELOPMENT. THE FIRST IS LAKE BREEZE BOUNDARY RUNNING
FROM THE E SIDE OF THE KEWEENAW TO CNTRL GOGEBIC COUNTY...AND THE
OTHER IS THE COLD FRONT MOVING ACROSS THE WRN PART OF LAKE SUPERIOR.
MOSTLY FOLLOWED RECENT RADAR TRENDS TO MOVE LINGERING WIDESPREAD
SHRA OUT OF THE ERN FCST AREA OVER THE NEXT FEW HRS. HELD LOW POPS
BACK TO THE W AHEAD OF THE TWO AFOREMENTIONED BOUNDARIES. LATEST SPC
MESOANALYSIS HAS MLCAPES UP TO AROUND 250J/KG OR SO AND SBCAPE TO
AROUND 500J/KG AHEAD OF THE BOUNDARIES. WITH CU BUILDING UP PER VIS
SATELLITE IMAGERY...CAN`T RULE OUT ISOLD/SCT SHRA DEVELOPMENT...
PERHAPS A TSTM. WHATEVER HAPPENS...PCPN RISK WILL BE DONE BY LATE
EVENING AS COLD FRONT SWEEPS ACROSS THE AREA. MUCH DRIER AIR MASS
SURGING INTO THE AREA WILL FINALLY BRING AN END TO THE UNSEASONABLY
LONG STRETCH OF HIGH DWPTS FOR THIS TIME OF YEAR. UPSTREAM IN NRN
MN...SFC DWPTS HAVE FALLEN THRU THE 40S WITH EVEN SOME 30S SHOWING
UP. EXPECT CLEARING SKIES FROM THE W TONIGHT. IF THERE IS ANY FOG ON
LAKE SUPERIOR...IT WILL AFFECT THE ERN SHORELINE AREAS BEFORE BEING
SWEPT CLEAR BY THE MUCH DRIER AIR MASS. IT WILL BE THE COOLEST NIGHT
IN WELL OVER A WEEK. MIN TEMPS SHOULD FALL INTO THE MID 40S OVER THE
INTERIOR W HALF AND MOSTLY LOW/MID 50S ELSEWHERE.
DRY AIR MASS WILL SET UP A NICE WED UNDER PLENTY OF SUNSHINE. DWPTS
WILL BE LOW...MOSTLY IN THE 40S...WITH HIGH TEMPS IN THE UPPER 60S
TO MID 70S...WARMEST IN THE AREAS THAT SEE DOWNSLOPING UNDER A
WESTERLY WIND. SPEAKING OF WHICH...WINDS SHOULD BE GUSTY INTO THE 20
TO 30 MPH RANGE...ESPECIALLY OVER THE NW FCST AREA.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 414 PM EDT TUE SEP 8 2015
THE UPPER TROUGH THAT IS CURRENTLY MOVING EAST ACROSS SOUTH CENTRAL
CANADA AND THE UPPER MISSISSIPPI VALLEY WILL MOVE INTO THE UPPER
GREAT LAKES OVER THE NEXT 12 HOURS AND THEN AMPLIFY OVER THE REGION
HEADING INTO THE END OF THE WORK WEEK AS A WAVE CURRENTLY MOVING
INTO BRITISH COLUMBIA ROTATES THROUGH. THIS SETUP WILL LEAD TO
GENERALLY BELOW NORMAL TEMPERATURES INTO THE START OF THE WEEKEND
WITH PERIODS OF SHOWERS.
AFTER A DRY START TO THE LONG TERM PERIOD ON WEDNESDAY EVENING
(DUE TO AN EXISTING HIGH PRESSURE RIDGE)...A WEAK SURFACE TROUGH
WILL MOVE EAST ACROSS THE UPPER MISSISSIPPI VALLEY AND INTO THE
GREAT LAKES REGION LATER WEDNESDAY NIGHT AND THURSDAY. THIS WILL BE
IN RESPONSE TO THE SHORTWAVE CURRENTLY MOVING INTO BRITISH COLUMBIA
THAT WILL BE ROUNDING THE BASE OF THE UPPER TROUGH. SHOWERS ARE
EXPECTED TO DEVELOP IN SOUTHERN MINNESOTA AND WESTERN WISCONSIN
ON WEDNESDAY NIGHT AND THEN SPREADING EAST-NORTHEAST INTO PORTIONS
OF UPPER MICHIGAN. MODELS ARE DIFFERING ON THE NORTHWEST EXTENT OF
THE SHOWERS...LARGELY DUE TO THE TRACK OF THE SHORTWAVE WITH HALF
TRACKING IT ACROSS NORTHERN WISCONSIN (PUSHING PRECIP FARTHER NORTH)
AND THE OTHER HALF TRACK IT MORE ACROSS SOUTHERN WISCONSIN (AND HAS
PRECIP ONLY BRUSHING THE SOUTHERN THIRD OF THE AREA) ON THURSDAY.
DID SEE A SOUTHEAST TREND WITH THE 12Z ECMWF...WHICH IS MORE IN LINE
WITH THE 12Z GFS/GEM...SO WHILE CONFIDENCE IS LOW...FELT IT WAS
REASONABLE TO TREND THE CHANCE POPS FARTHER TO THE SOUTHEAST AND
MORE OVER THE SOUTH CENTRAL AND ALONG THE LAKE MICHIGAN SHORELINE.
THOSE SHOWERS WILL DEPART ON THURSDAY NIGHT AS THE SHORTWAVE AND
SURFACE TROUGH DEPARTS. THIS WILL ALLOW MUCH COLDER AIR TO SURGE
SOUTH ACROSS THE AREA THURSDAY NIGHT INTO FRIDAY...WITH 850MB TEMPS
FALLING TO 1-2C. SINCE LAKE SUPERIOR TEMPERATURES ARE IN THE 12-18C
RANGE...EXPECT SOME POTENTIAL OF LAKE EFFECT/ENHANCED RAIN FOR
THURSDAY NIGHT INTO FRIDAY. MODELS SHOWING DECENT MOISTURE BELOW
THE INVERSION AROUND 750MB...SO HAVE CHANCE POPS FOR THE FAVORED
NORTHERLY WIND LOCATIONS NEAR LAKE SUPERIOR DURING THAT TIME.
WILL LIKELY NEED TO TREND POPS UP FURTHER IF THE LATEST MODEL
TRENDS CONTINUE. IN ADDITION...THAT COLD AIR AND DECENT CLOUD COVER
FOR MUCH OF THE DAY ON FRIDAY WILL KEEP HIGHS IN THE 50S.
A SURFACE HIGH OFF TO THE WEST IN THE DAKOTAS WILL TRY TO PUSH A
SURFACE RIDGE INTO THE AREA ON FRIDAY...BUT IT WILL LIKELY REALLY
ARRIVE ON SATURDAY AS THE UPPER TROUGH BEGINS TO SHIFT EAST. DRIER
AIR ASSOCIATED WITH THE HIGH WILL LEAD TO DECREASING CLOUDS FROM
WEST TO EAST ON FRIDAY AFTERNOON...WITH CLEAR SKIES REMAINING IN
PLACE THROUGH MUCH OF THE WEEKEND. SATURDAY WILL REMAIN BELOW
NORMAL FOR HIGHS...BUT WITH THE UPPER RIDGE AXIS SHIFTING EAST FROM
THE DAKOTAS AND INTO THE UPPER GREAT LAKES REGION FOR SUNDAY AND
MONDAY...EXPECT HIGHS TO RISE BACK UP TO NORMAL OR EVEN SLIGHTLY
ABOVE NORMAL VALUES. WILL NEED TO WATCH THE EVOLUTION OF THE UPPER
TROUGH JUST TO THE EAST-SOUTHEAST OF THE AREA FOR SUNDAY/MONDAY
TIME FRAME...AS THERE ARE SOME HINTS OF IT ROTATING BACK NORTHWEST
AS THE UPPER RIDGE REMAINS FARTHER WEST. THAT WOULD LEAD TO COOLER
AND BETTER OPPORTUNITIES FOR RAIN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 150 PM EDT TUE SEP 8 2015
MUCH DRIER AIR WILL SWEEP INTO THE AREA BEHIND A DEPARTING
DISTURBANCE AND PASSING COLD FRONT. AT KIWD...VFR CONDITIONS WILL BE
THE RULE THROUGH THE FCST PERIOD. AT KCMX/KSAW...ANY LINGERING
IFR/LIFR CONDITIONS WILL CLEAR OUT IN THE NEXT HOUR OR TWO WITH VFR
CONDITIONS TO PREVAIL THEREAFTER. SHRA WILL ALSO END AT KSAW IN THE
NEXT FEW HRS. A PERIOD OF GUSTY WINDS UP TO 25KT WILL OCCUR BEHIND
FROPA AT KCMX THIS EVENING. GUSTY WINDS OF 18-25KT...STRONGEST AT
KCMX...ARE EXPECTED AT ALL TERMINALS BY LATE WED MORNING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 417 PM EDT TUE SEP 8 2015
FIRST UP...IF THERE IS ANY FOG ON LAKE SUPERIOR...IT WILL BE SWEPT
OFF THE ERN PORTION OF THE LAKE TONIGHT AS STRENGTHENING W WINDS
BEHIND A PASSING COLD FRONT USHER IN A MUCH DRIER AIR MASS TONIGHT.
INCOMING PRES RISES WILL HELP BOOST W WIND GUSTS TO 25-30KT FOR A
TIME AFTER FRONTAL PASSAGE. DURING WED...W WINDS OF 15-25KT WILL
GENERALLY BE THE RULE...BUT OVER CNTRL LAKE SUPERIOR AND IN
PARTICULAR AROUND THE TIP OF THE KEWEENAW PENINSULA...WINDS OF 20-
30KT ARE EXPECTED. LIGHTER WINDS OF 10-20KT ARE EXPECTED FOR WED
NIGHT/THU. ARRIVAL OF A COLDER AIR MASS AHEAD OF APPROACHING SFC
HIGH PRES WILL LEAD TO A PERIOD OF STRONGER WINDS OF 15-30KT AGAIN
THU NIGHT INTO AT LEAST FRI MORNING...STRONGEST OVER THE E HALF.
WINDS WILL SLOWLY DIMINISH W TO E FRI AFTN THRU SAT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...ROLFSON
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
157 PM EDT TUE SEP 8 2015
.UPDATE...
SPC ANALYSIS SUPPORTS MODEL IDEA OF ML CAPE BUILDING TO AROUND
1500 J/KG THIS AFTERNOON. A FEW SHOWERS HAVE JUST STARTED TO POP
UP OVER SOUTHEAST MICHIGAN...IN ADDITION TO THE LINE OF
SHOWERS/TSTORMS THAT STRETCHES FROM CENTRAL LAKE MICHIGAN DOWN
THROUGH CHICAGO. LINE SHOULD BE MAINTAINED AND POTENTIALLY
STRENGTHEN AS IT WORKS INTO THE WARM UNSTABLE AIRMASS. BIGGEST
THREAT ASIDE FROM HEAVY RAINFALL WOULD BE WIND GUSTS TO 50 MPH
GIVEN STRONGER CORE OF WINDS ALOFT AND SOME DRIER AIR BELOW 4000
FEET.
&&
.AVIATION...
POCKET OF SUNSHINE WILL ALLOW SCT-BKN CUMULUS DECK TO FILL IN 18-
19Z...WITH CEILINGS LOOKING TO SETTLE IN THE 3500-5000 FT RANGE. THE
SUN HAS ALSO ALLOWED INSTABILITY TO BUILD...AND LINE OF
THUNDERSTORMS STRETCHING FROM CENTRAL LAKE MICHIGAN TO CHICAGO
SHOULD BE ABLE TO MAINTAIN ITSELF AS IT WORKS EAST DURING THE LATE
AFTERNOON AND EVENING. A 2-HR TEMPO WINDOW HAS BEEN ADDED INTO TAFS
TO HANDLE THIS LINE MOVING ACROSS THE TERMINALS...WITH PRELIMINARY
TIMING BETWEEN 20Z AND 02Z. AN AREA OF RAIN WITH EMBEDDED THUNDER
AND MVFR CEILINGS/VIS SHOULD THEN DROP DOWN INTO THE AREA FROM
NORTHERN MICHIGAN THIS EVENING AND OVERNIGHT AS WEAK LOW PRESSURE
TRACKS THROUGH THE REGION.
FOR DTW...LINE OF STORMS NEAR CHICAGO WILL PROGRESS WESTWARD THIS
AFTERNOON AND EVENING...POTENTIALLY STRENGTHENING. CURRENT TIMING
PER LINEAR EXTRAPOLATION WOULD BE AROUND 00Z...HOWEVER THE LINE
COULD SLOW AS IT BECOMES ORIENTATED TOWARDS FLOW OR EVEN SPEED UP IF
IT STRENGTHENS. HAVE INCLUDED A TEMPO GROUP BETWEEN 00Z AND 02Z TO
COVER...BUT ADJUSTMENTS COULD BE NECESSARY. AREA OF RAIN OVER
NORTHERN MICHIGAN IS EXPECTED TO DROP INTO THE AREA AROUND
04Z...DROPPING CEILINGS/VIS TO MVFR. A PERIOD OF IFR VISIBILITIES
COULD OCCUR BETWEEN WHEN THE RAIN ENDS AND WHEN A WEAK COLD FRONT
WORKS THROUGH WEDNESDAY MORNING.
//DTW THRESHOLD PROBABILITIES...
* MEDIUM FOR THUNDERSTORMS IN THE DTW AIRSPACE BEFORE 02Z. LOW
AFTER 02Z.
* MEDIUM FOR CIGS AOB 5KFT THIS AFTERNOON. HIGH OVERNIGHT AND EARLY
WEDNESDAY.
&&
.PREV DISCUSSION...ISSUED 340 AM EDT TUE SEP 8 2015
SHORT TERM...TODAY AND TONIGHT
ABSENT FORCING, THE RESERVOIR OF SIGNIFICANT MOISTURE ABOVE 700MB ON
LAST NIGHT`S 00Z DTX SOUNDING REMAINED QUIET THROUGH ABOUT 06Z.
HOWEVER, WARM ADVECTION WITHIN STRENGTHENING SWLY FLOW BEGAN TO
IGNITE CONVECTION ROUGHLY ALONG A CHICAGO TO PORT HURON LINE BY 07Z.
CONDITIONS WILL REMAIN FAVORABLE FOR EXPANSION OF THIS ACTIVITY
THROUGH THE MORNING AS FLOW CONTINUES TO INCREASE AND DAYTIME
HEATING ADDS A FEW HUNDRED J/KG CAPE TO THE PROFILE. THROUGH 18Z,
CONVECTION IS EXPECTED TO BE CONFINED MAINLY NORTH OF M59 ALONG WITH
THE BETTER FORCING. PWATS AROUND 2", LOW DENSITY CAPE, AND AN
INCREASINGLY DEEP WARM CLOUD LAYER WILL SUPPORT A HEAVY RAIN THREAT
FOR ANY AREAS THAT RECEIVE RAIN THROUGH TONIGHT. LOCALIZED FLOODING
IS NOT OUT OF THE QUESTION GIVEN SLOWER STORM MOTION AND THE
POTENTIAL FOR SOME AREAS ACROSS THE NORTHWEST TO SEE MULTIPLE ROUNDS
OF RAINFALL.
A SECOND AND STRONGER LLJ SURGE WILL ARRIVE BY AFTERNOON IN ADVANCE
OF THE SHORTWAVE NOTED OVER NORTHWEST MISSOURI AT 07Z THIS MORNING.
DYNAMIC FORCING WILL BE STOUT, BUT WILL ONLY OCCUR OVER A RELATIVELY
SMALL SPATIAL FOOTPRINT, MOST OF WHICH WILL BE OVER WESTERN AND
NORTHERN LOWER. HOWEVER, 06Z RAP INDICATES THAT THE CORE OF THE
ASSOCIATED 35-40KT LLJ WILL ALIGN ALONG A MUSKEGON TO WEST BRANCH
LINE 21-00Z WHICH WILL PUT THE SAGINAW VALLEY IN LINE TO RECEIVE A
NOTEWORTHY BOOST IN FORCING DUE TO DIFFERENTIAL WARM ADVECTION LATE
IN THE PEAK HEATING PERIOD. THUS, EVEN IF THE STRONGER DYNAMIC
FORCING DOES MANAGE TO MISS THE CWA...AND AT THIS TIME IT`S PROGGED
TO JUST GRAZE THE SAGINAW VALLEY AREA...NORTHWESTERN AREAS SHOULD
STILL SEE SOME EASTWARD EXPANSION OF CONVECTION DURING THE MID TO
LATE AFTERNOON DUE TO THE STRENGTHENING LLJ.
THE BULK OF THE RAIN SHIELD WILL EVENTUALLY PEEL NORTH ALONG WITH
THE DEPARTING WAVE, BUT LARGER SCALE FORCING EMBEDDED WITHIN THE
RIGHT ENTRANCE OF A 130KT UPPER JET OVER LAKE SUPERIOR WILL SUPPORT
A WAVE OF SHOWERS SLOWLY TRAVERSING THE REMAINDER OF THE AREA
ROUGHLY 00Z-12Z WED. THESE, TOO, WILL CARRY THE SAME THREAT FOR
HEAVY RAIN, THOUGH A DIMINISHED THREAT FOR FLOODING WILL EXIST DUE
TO INCREASINGLY PROGRESSIVE LARGER SCALE FORCING.
LONG TERM...
A STRONG WAVE ENTERING THE BASE OF THE MID/UPPER LEVEL TROUGH
CENTERED OVER WESTERN ONTARIO WILL PROVIDE THE NEEDED BOOST TO
USHER THE LINGERING FRONTAL BOUNDARY OFF TO THE EAST WEDNESDAY.
TIMING IS STILL NOT IRONED OUT EXACTLY AS THE INCOMING WESTERLY
JET MAX TURNS MORE NORTHEASTERLY ONCE IT PHASES WITH THE EXISTING
JET ALIGNED WITH THE FRONT. SO EXPECT THE FRONT TO BECOME MORE
PROGRESSIVE AS THE PARENT SYSTEM GAINS SPEED...BUT WITH THE SE
RIDGE STILL REACHING UP INTO THE EASTERN GREAT LAKES WE CAN EXPECT
SHOWERS TO LINGER OVER THE EASTERN COUNTIES INTO THE AFTERNOON
HOURS WEDNESDAY. THE FRONT WILL PUSH THE ENHANCED RIBBON OF
MOISTURE...NEAR 2 INCH PWATS...OFF TO THE EAST BY MIDDAY WEDNESDAY
BUT RESIDUAL MOISTURE POOL BETWEEN 1- 1.5 INCHES WILL STILL LINGER
THROUGH THE AFTERNOON UNTIL A SECONDARY TROUGH DROPS THROUGH LOWER
MI. THE NAM IS VERY BULLISH ON GENERATING SHOWERS WITH THIS
SECONDARY TROUGH IN PART DUE TO ELEVATED LL LAPSE RATES IN THE
WAKE OF THE FRONT. THERE IS SOME SIGNAL IN THE EURO/GFS BUT WITH
THE STRENGTH OF THE FRONTAL CIRCULATION...EXPECT A GOOD DEAL OF
SUBSIDENCE IN ITS WAKE COMBINED WITH THE BUILDING RIDGE. IN
ADDITION...THE NAM HAS BEEN DEVELOPING A SFC LOW ALONG THE FRONT
PASSING JUST TO OUR SOUTH THROUGH TOLEDO WEDNESDAY
AFTERNOON/EVENING. THIS WOULD RESULT IN ADDITIONAL DEFORMATION
FORCING LINGERING OVER SE MI AFTER 00Z THURSDAY. BUT AGAIN...NO
OTHER MODEL HAS ANYTHING NEARLY AS ORGANIZED AT THIS TIME.
SOMETHING TO WATCH BUT IN THE MEANTIME...FORECAST WILL FEATURE
CHANCE POPS DECREASING THROUGH THE DAY FROM NORTHWEST TO
SOUTHEAST.
WITH THE FRONT TO OUR SOUTH...PRECIP AND OVERCAST SKIES...HIGH
TEMPERATURES WILL TAKE A NOTABLE DIVE WEDNESDAY TOPPING OUT IN THE
UPPER 70S. THE SECONDARY TROUGH LATE WEDNESDAY WILL BRING ABOUT
COOLER WEATHER WITH NORTHERLY FLOW DROPPING HIGHS INTO THE MID 70S
FOR THURSDAY. TEMPS WILL TAKE A FURTHER NOSE DIVE INTO THE WEEKEND
AS YET ANOTHER FRONT SWEEPS THROUGH THE REGION ON FRIDAY BRINGING
THE NEXT CHANCE OF PRECIP WITH IT. MID MI MAY SEE SOME PRECIP
THURSDAY/THURSDAY NIGHT AS IT DRAPES SW TO NE THROUGH NORTHERN
LOWER...BUT MOST OF SE MI WILL REMAIN DRY TIL FRIDAY. MODELS DIVERGE
QUITE A BIT FOR THE WEEKEND IN THE HANDLING OF THIS NEXT UPPER
TROUGH...BUT CONSENSUS IS TROUGHING WILL HOLD OVER THE REGION WITH
ADDITIONAL SHOTS OF COOLER AIR WITH EACH FRONT. 850MB COLD POOL WILL
SET UP OVER THE GREAT LAKES WITH TEMPS POTENTIALLY DOWN INTO THE MID
SINGLE DIGITS AS HIGH PRESSURE SETTLES OVER THE REGION FROM CANADA.
MARINE...
A COLD FRONT DRAPED ACROSS THE CENTRAL GREAT LAKES IS RESULTING IN
WEAK FLOW WITHIN THE TROUGH OF LOW PRESSURE. THE EXCEPTION WOULD BE
LAKE ERIE AND LAKE ST CLAIR WHOM WILL CONTINUE TO RESIDE IN THE
SOUTHWESTERLY FLOW IN ADVANCE OF THE FRONT THROUGH THIS EVENING. THE
FRONT WILL BRING ABOUT A NOTABLE WIND SHIFT TONIGHT OVER LAKE HURON
TO NORTHWESTERLY...WHILE A TIGHTENED GRADIENT PROVIDES A BOOST TO
WIND SPEEDS WHICH WILL RANGE BETWEEN 20 AND 25 KNOTS POST COLD
FRONT. THIS FLOW WILL CONTINUE THROUGH WEDNESDAY AND WEDNESDAY NIGHT
AS A SECONDARY FRONT THEN DROPS THROUGH THE REGION. HIGH PRESSURE
WILL ALLOW WINDS TO RELAX ON THURSDAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
UPDATE.......HLO
AVIATION.....HLO
SHORT TERM...JVC
LONG TERM....DRK
MARINE.......DRK
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
119 PM EDT TUE SEP 8 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 329 AM EDT TUE SEP 8 2015
PERIODS OF SHOWERS AND THUNDERSTORMS WILL PREVAIL TODAY INTO THIS
EVENING BEFORE A SLOW MOVING COLD FRONT PUSHES THEM SOUTH OF THE
AREA BY MID MORNING WEDNESDAY. AREAS OF LOCALIZED HEAVY RAINFALL
ARE POSSIBLE. IT WILL CONTINUE TO BE VERY HUMID TODAY BUT NOT
QUIET AS WARM AS THE PAST FEW DAY. COOLER AND SIGNIFICANTLY DRIER
AIR WILL FOLLOW THE COLD FRONT FOR WEDNESDAY AND SUNSHINE SHOULD
PREVAIL IN MOST AREAS BY MID AFTERNOON. A SECONDARY COLD FRONT
WILL COME THROUGH THE AREA ON FRIDAY WITH SCATTERED SHOWERS. THIS
COMING WEEKEND SHOULD BE MOSTLY CLEAR WITH MUCH COOLER
TEMPERATURES...HIGHS MAY ONLY REACH THE MID 60S ON SATURDAY.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 329 AM EDT TUE SEP 8 2015
OUR PRIMARY ISSUE CONTINUES TO BE THE THREAT FOR HEAVY RAINFALL.
PRECIPITABLE WATER CONTINUES TO RUN BETWEEN 1.8 AND 2.0 INCHES
OVER MOST OF THE CWA TODAY. THIS IS AROUND 3 TIMES NORMAL AND IS
APPROACHING ALL TIME RECORD VALUES FOR THIS TIME OF YEAR. ADD TO
THAT A FRONTAL BOUNDARY SLOWLY MOVING THROUGH THE AREA...AIDED BY
THE ENTRANCE REGION OF THE POLAR JET AND A SHORTWAVE FROM IOWA...
AND THERE IS LITTLE QUESTION SOME OF THE STORMS WILL PRODUCE
HEAVY RAINFALL. CORFIDI VECTORS WILL BE BELOW 10 MILE PER HOUR
THIS MORNING AND RISE TO AROUND 15 MPH THIS AFTERNOON. THAT TOO
WILL AID IN THE LOCALLY HEAVY RAINFALL. I STILL BELIEVE SOME
ISOLATED RAINFALL AMOUNTS MAY BE CLOSE TO 5 INCHES FROM THIS
EVENT.
WE HAVE THE REMAINS OF YESTERDAYS OUTFLOW BOUNDARY STALLED
BETWEEN I-94 AND I-96 EARLY THIS MORNING. AS THE SHORTWAVE FROM
IOWA MOVES CLOSER TO THIS AREA WILL BE THE FOCUS FOR CONVECTION
THIS MORNING. WHICH SUGGESTS THE STORMS WILL MOSTLY BE SOUTH OF
I-96 AT FIRST BUT THEN LIFT NORTHWARD WITH TIME. BY LATE MORNING
INTO EARLY AFTERNOON I WOULD EXPECT MOST OF THE CONVECTION TO BE
NORTH OF I-96. THEN AS THE PRIMARY COLD FRONT AND SHORTWAVE MOVE
INTO THE AREA.. THE RAP MODEL SHOWS A 30 - 35 KNOT LOW LEVEL JET
MOVING INTO THE AREA BY MID AFTERNOON. THE CORE OF THE SPEED MAX
WILL BE JUST NORTH OF I-96 AND BE EAST OF MKG BY 4 PM AND BE NORTH
OF LANSING BY 8 PM. THIS SUGGEST TO ME THE STRONGEST CONVECTION
WILL BE DURING THE LATE AFTERNOON AND EARLY EVENING.
THERE IS A MARGINAL RISK FOR SEVERE STORMS (SPC) TODAY... WITH THE
NARROW CAPE... AND NUMEROUS HEAVY SHOWERS AROUND... AND ONLY
MARGINAL DEEP LAYER SHEAR... I WOULD IMAGINE ANY SEVERE WEATHER
WOULD BE VERY ISOLATED TODAY.
ONCE THE COLD FRONT COMES THROUGH MOST OF THE CONVECTION WILL EXIT
WITH IT THIS EVENING. HIGH PRESSURE FOLLOWS FOR WEDNESDAY INTO
THURSDAY. CLEARING SKIES FROM NORTHWEST TO SOUTHEAST WEDNESDAY
AFTERNOON. I WOULD EXPECT MOSTLY CLEAR SKIES WEDNESDAY NIGHT INTO
THURSDAY AS THE HIGH MOVES OVERHEAD.
BOTTOM LINE IS WET TODAY...DRY WEDNESDAY AFTERNOON INTO THURSDAY
EVENING.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 329 AM EDT TUE SEP 8 2015
A NICE COOL DOWN IS EXPECTED BY THE END OF THE WEEK AS A DEEP UPPER
TROUGH DEVELOPS OVER THE GREAT LAKES. WE/LL SEE TEMPERATURES IN THE
60S FRIDAY THROUGH SUNDAY ALONG WITH SOME SHOWERS FRIDAY AND
SATURDAY. MODEL CONCERNS ARE SIMILAR TO YESTERDAY AS THE ECMWF
DEEPENS THE LOW AND THEN CUTS IT OFF OVER MICHIGAN SUNDAY WHILE THE
GFS KEEPS THE SYSTEM AN OPEN WAVE AND THEN SCOOTS IT EASTWARD BY
SUNDAY. THE GFS WOULD LEAD TO WARMER TEMPS AND LESS PCPN THAN THE
SLOWER COOLER ECMWF. WE/RE LEANING TOWARD THE GFS SOLUTION AS IT
ALSO LINES UP NICELY WITH THE LATEST FIM. THUS ANY SHOWERS SHOULD
END BY LATE SATURDAY LEADING TO DRY WX SUNDAY AND MONDAY AND WARMER
TEMPS AS RIDGING BUILDS INTO SW LWR MI.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 115 PM EDT TUE SEP 8 2015
THE LINE OF THUNDERSTORMS APPROACHING KMKG WILL LIKELY CROSS THE
TAF SITES THROUGH THE AFTERNOON. THEREFORE I INCLUDED A BRIEF
PERIOD OF IFR AND GUSTY WINDS FOR EACH TAF SITE. AFTER THAT...IT
APPEARS LESS OF A RISK OF THUNDER.
FOG/STRATUS COULD BE AN ISSUE TONIGHT AS THE WIND DIMINISH AND THE
LOW LEVELS BECOME MORE HUMID. AS A RESULT I DID PUT MVFR/IFR CONDITIONS
IN THE FORECASTS.
&&
.MARINE...
ISSUED AT 1224 PM EDT TUE SEP 8 2015
NEARSHORE BOUYS FROM GRAND HAVEN TO LUDINGTON SHOWING WAVES OF 2
TO 4 FEET. LOOKS LIKE THE WAVES ARE ASSOCIATED WITH AN AREA OF
ENHANCED SOUTH WINDS OF 15 TO 20 KTS AHEAD OF THE APPROACHING COLD
FRONT AND THUNDERSTORM ACTIVITY. LARGEST WAVES OF 4FT SHOULD
CONTINUE TO SPREAD NORTHWARD TOWARDS LUDINGTON WHILE WAVES SHOULD
BEGIN TO SUBSIDE SOUTH OF MUSKEGON.
STILL EXPECTING VISIBILITY BELOW 1 MILE IN SHOWERS AND
THUNDERSTORMS THIS AFTERNOON AND CONTINUING INTO THIS EVENING
SOUTH OF MUSKEGON. FIRST BATCH WILL MOVE ONSHORE BY 6PM WITH A
SECOND AREA OF SHOWERS AND FOG OVER SOUTH HALF OF THE LAKE
OVERNIGHT.
POSSIBLY SCA FOR WED WITH GUSTY WEST WINDS BEHIND COLD FRONT.
LOOKING FOR OCCASIONAL GUSTS TO 25 KTS AND BUILDING SEAS OF 3 TO 5
FEET THROUGH THE AFTERNOON.
&&
.HYDROLOGY...
ISSUED AT 1207 AM EDT TUE SEP 8 2015
A FLOOD ADVISORY IS ONGOING FOR HOLT ON THE SYCAMORE CREEK. THE
STAGE CONTINUES TO RISE...BUT THE RATE OF RISE IS NOT QUITE AS
STEEP AS IT WAS EARLIER THIS MORNING. CURRENT CRESTS THAT ARE
FORECAST WILL BE HIGHLY DEPENDENT ON TONIGHTS RAINFALL AMOUNTS.
A COMPLEX OF SHOWERS AND THUNDERSTORMS THAT DEVELOPED OVER THE
UPPER MIDWEST LATE LAST NIGHT CONTINUE TO PROGRESS NORTHEAST
THROUGH THE NORTHERN GREAT LAKES. A LINE OF SHOWERS AND
THUNDERSTORMS CURRENTLY EXTENDS FROM CENTRAL LAKE MICHIGAN AND
SOUTHWEST INTO ILLINOIS. THIS LINE CONTINUES TO EXPAND AS IT
PRESSES EASTWARD. FOR SOME LOCATIONS...THIS WILL BE THE SECOND
ROUND OF RAINFALL TODAY. HEAVY RAIN OF ONE TO TWO INCHES IS
POSSIBLE...ESPECIALLY IN OR NEAR THUNDERSTORMS.
ANOTHER WAVE OF PRECIPITATION MAY DEVELOP FURTHER SOUTH AND WEST
OVERNIGHT...ACROSS THE SOUTHERN HALF OF LOWER MICHIGAN...WHICH
COULD BRING ADDITIONAL PERIODS OF HEAVY RAIN. OVERALL RAINFALL
TOTALS COULD EXCEED TWO INCHES IN LOCATIONS AFFECTED BY REPEATED
EVENTS. LOCALIZED FLOODING TO URBAN AREAS AND PONDING OF ROADWAYS
COULD OCCUR DURING AND CLOSELY FOLLOWING HEAVY RAINFALL. AREAS
STREAMS AND RIVERS MAY RISE DUE TO QUICK RUNOFF AS MANY LOCATIONS
ALREADY HAVE SATURATED SOILS.
DRY WEATHER IS ANTICIPATED TO RETURN BY MID MORNING WEDNESDAY.
THIS SHOULD ALLOW RIVERS TIME TO STABILIZE WEDNESDAY INTO
THURSDAY.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...99
AVIATION...MJS
HYDROLOGY...JAM
MARINE...COBB
AREA FORECAST DISCUSSION
NWS GAYLORD MI
100 PM EDT TUE SEP 8 2015
.UPDATE...
ISSUED AT 959 AM EDT TUE SEP 8 2015
SHOWERS AND EMBEDDED THUNDERSTORMS ARE STEADILY EXPANDING IN AREAL
COVERAGE ACROSS THE SRN HALF OF OUR CWA LATE THIS MORNING AS DEEP
MOISTURE SURGES NORTH INTO NORTHERN MICHIGAN AHEAD OF A LARGE AREA
OF WIDESPREAD CONVECTION. LATEST DAY 1 OUTLOOK HAS EXPANDED THE
MARGINAL AREA INTO MUCH OF NRN LWR MICHIGAN...ANTICIPATING SOME
DIURNAL DESTABILIZATION THIS AFTERNOON COMBINED WITH SOME INCREASE
IN WIND SPEEDS WELL ALOFT AT THE ANVIL LEVEL. LATEST RAP13 IS
RATHER AGGRESSIVE IN BOOSTING MUCAPES THIS
AFTERNOON...APPROACHING 1700 JOULES IN OUR SE CWA. MEANWHILE...THE
LATEST HRRR SEEMS TO BE UNIMPRESSED WITH THE PROSPECT OF DIURNAL
DESTABILIZATION... SUGGESTING CAPES WILL ONLY REACH TO 250-500
JOULES. LATEST NAM12 LIES SOMEWHERE IN BETWEEN. TEND TO SIDE WITH
THE HRRR GIVEN AMPLE CLOUDS AND PRECIP ACROSS OUR ENTIRE
CWA...INCLUDING OUR SE CWA WHERE THE OTHER TWO MODELS SHOW
GREATEST DESTABILIZATION.
STILL EXPECT SVR CHANCES ARE MINIMAL...BUT WILL CERTAINLY MAINTAIN
CHANCES OF THUNDER ACROSS OUR ENTIRE CWA THRU TODAY AND INTO
EARLY EVENING. WILL ALSO KEEP CATEGORICAL POPS FOR MUCH OF NRN LWR
MICHIGAN...AND WILL KEEP A CLOSE EYE ON ERN UPR MICHIGAN WHERE WE
MAY NEED TO INCREASE POPS FROM LIKELY TO CATEGORICAL AS THIS EVENT
PLAYS OUT TODAY.
&&
.NEAR TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 431 AM EDT TUE SEP 8 2015
...WET DAY AHEAD BUT LAST DAY OF HUMIDITY...
HIGH IMPACT WEATHER POTENTIAL: LOCALLY HEAVY DOWNPOURS POSSIBLE
TODAY.
PATTERN SYNOPSIS/FORECAST: MIDNIGHT SURFACE/COMPOSITE ANALYSIS SHOWS
A COLD FRONT DRAPED ACROSS NORTHEAST/CENTRAL LOWER MICHIGAN AND
EXTENDING BACK ACROSS SOUTHERN LAKE MICHIGAN AND ALONG THE
WISCONSIN/ILLINOIS BORDER INTO SOUTHERN IOWA. SMALL BUBBLE OF HIGH
PRESSURE (1017MB) WAS CENTERED OVER THE MINNESOTA ARROWHEAD. SOUPY
AIR MASS LINGERS OVER THE UPPER LAKES AND POINTS SOUTH AND
SOUTHWEST...GOES PRECIPITABLE WATER ANALYSIS SHOWS AN ARC OF 40-50MM
VALUES FROM THE LOWER LAKES/SOUTHERN LOWER MICHIGAN BACK TO THE MID
MISSISSIPPI VALLEY AND THE EASTERN PLAINS. 00Z APX SOUNDING DOES
SHOW SOME ELEVATED INSTABILITY (ON THE ORDER OF 1200J/KG MUCAPE)...A
FEW SPOTTY SHOWERS HAVE BEEN POPPING UP SOUTH OF M-32 LIKELY
ASSOCIATED WITH WEAK ISENTROPIC ASCENT AS OVERALL WIND FLOW IS LIGHT
BELOW 700MB...WITH A ROUGE SHOWER OVER LUCE COUNTY. MORE WIDESPREAD
RAINFALL HAS BEEN CONGEALING OVER THE MIDWEST.
DIFFUSE FRONT LYING ACROSS LOWER MICHIGAN WILL LIKELY BE MOSTLY
STATIONARY TODAY...BUT WITH PLENTY OF MOISTURE AROUND. STRONGER
SHORT WAVE TROUGH OVER THE ROCKIES WILL PUSH INTO THE UPPER
MIDWEST/UPPER LAKES TONIGHT...WHICH IN TURN WILL ALLOW A SECONDARY
COLD FRONT TO SLICE ACROSS MICHIGAN OVERNIGHT AND FINALLY KNOCK DOWN
THIS PERSISTENTLY HUMID AIR MASS.
PRIMARY FORECAST CONCERNS: DETAILS REGARDING RAINFALL OVER NEXT 24
HOURS.
TODAY...LOOKS LIKE TODAY SHOULD BE RELATIVELY STRAIGHTFORWARD...AS
COMBINATION OF WHAT IS CURRENTLY POPPING OVER LOWER MICHIGAN...AND
ARRIVAL LATER THIS MORNING OF UPSTREAM PRECIPITATION EXPECTED TO
RESULT IN PERIODS OF RAIN...ALONG WITH SOME EMBEDDED THUNDER. AS
HAS BEEN THE CASE RECENTLY...PRECIPITATION SHOULD BE PRETTY
EFFICIENT GIVEN DEEP LAYER MOISTURE (PRECIPITABLE WATER 1.50-2.00
INCHES EXPECTED AND A FAIRLY DEEP WARM LAYER). GENERAL RAINFALL
AMOUNTS OF 0.50-1.00 INCH EXPECTED ACROSS NORTHERN LOWER MICHIGAN...
WITH HIGHER AMOUNTS POSSIBLE DEPENDING ON EVOLUTION OF PRECIPITATION
THOUGH THAT IS SOMEWHAT UNCERTAIN GIVEN RATHER WEAK FOCUSING
MECHANISMS.
TONIGHT...COUPLE ROUNDS OF PRECIPITATION POSSIBLE FOR TONIGHT. LAST
OF THE DAYTIME PRECIPITATION WILL BE PUSHING INTO LAKE HURON DURING
THE MID-LATE EVENING HOURS...AND GIVEN LIGHT FLOW WILL PROBABLY BE
FOLLOWED BY FOG/STRATUS DEVELOPMENT. APPROACH OF SECONDARY COLD
FRONT AND ASSOCIATED SHORT WAVE TROUGH...AS WELL AS RIGHT ENTRANCE
JET FORCING MAY RESULT IN SCATTERED ADDITIONAL DEVELOPMENT AS THIS
FRONT PASSES.
&&
.SHORT TERM...(WEDNESDAY THROUGH THURSDAY NIGHT)
ISSUED AT 431 AM EDT TUE SEP 8 2015
HIGH IMPACT WEATHER: NONE
(9/9)WEDNESDAY...MODELS HAVE COME TOGETHER AND NOW HAVE THE RAIN OUT
OF THE AREA. THE SFC HIGH PRESSURE BUILDS INTO THE LOWER MICHIGAN
AND HOLDS THROUGH THE DAY AND MOST OF THE NIGHT. A SFC TROUGH BEGINS
TO DEVELOP IN RESPONSE TO THE 500 MB SHORTWAVE TROUGH JUST UPSTREAM
IN MINNESOTA, AND ALONG THE THERMAL GRADIENT RUNNING THROUGH LAKE
SUPERIOR, BETWEEN 06Z AND 12Z WHICH BEGINS TO PRODUCE RAIN TO THE
WEST, IN WISCONSIN. AT THIS POINT, IT LOOKS LIKE THE RAIN SHOULD
STAY WEST, AS THE NAM/ECMWF CONTINUE TO KEEP THE SHORTWAVE TROUGH TO
FARTHER WEST THAN THE GFS.
(9/10)THURSDAY...THE SFC RIDGE BREAKS DOWN AS THE 500 MB SHORTWAVE
PUSHES, THE COLD FRONT THROUGH THE REGION. INSTABILITY IS PRETTY
SMALL, AND SINCE WE ALREADY HAVE RAIN SHOWERS WITH A SLIGHT CHANCE
OF THUNDER, WILL KEEP THAT AT THIS POINT, BUT GETTING THE FEELING
WITH THE COOLER SFC TEMPERATURES (IN THE LOWER 70S WEDNESDAY AND
THURSDAY) THAT THERE WON`T BE REALLY ENOUGH INSTABILITY FOR THUNDER.
THEN OVERNIGHT, THE RAIN SHOWERS, OR MAYBE IT WILL JUST BE AN AREA
OF RAIN, SET UPS WAS THE SHORTWAVE AND TROUGH MOVES INTO THE REGION.
AS THE SHORTWAVE PROGRESSIVELY MOVES IN, COLDER 850 MB AIR CONTINUES
INTO THE REGION AS WELL SO THAT WE WILL PROBABLY SET UP LAKE EFFECT
RAIN, ALTHOUGH WITH THE 1000-850 MB LAYER WIND OUT OF THE NORTH-
NORTHEAST, WE`LL STAY OUT OF IT INITIALLY UNTIL FRIDAY.
&&
.LONG TERM...(FRIDAY THROUGH MONDAY)
ISSUED AT 431 AM EDT TUE SEP 8 2015
EXTENDED (FRIDAY THROUGH MONDAY)...THE MODELS ARE BEGINNING TO COME
TOGETHER ON THE EVOLUTION OF THE DIGGING 500 MB SHORTWAVE TROUGH
OVER THE GREAT LAKES. THE ECMWF ISN`T AS DEEP OR CUT OFF AND THE GFS
IS A LITTLE DEEPER. THE ECMWF DOES PUSH THE RAIN THROUGH FASTER AS
WELL AS THE CUT OFF SO THAT THE TIMING THE END OF THE RAIN ON FRIDAY
IS PRETTY CLOSE AND THAT THE COOL DRY WEATHER WILL CONTINUE ON
SATURDAY. SUNDAY, TOO, LOOKS DRY, AND THEN A COLD FRONT PUSHES INTO
THE REGION ON THE GFS SUNDAY NIGHT INTO MONDAY, WHILE THE ECMWF IS
DRY UNTIL MONDAY NIGHT. ONE OTHER CONCERN IS FOR FRIDAY...THERE IS A
LOW END THREAT FOR WATERSPOUTS WITH AN UPPER LOW, DELTA TS OF 16C
AND CLOUD DEPTHS OF 5000-10000 FEET.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 100 PM EDT TUE SEP 8 2015
WIDESPREAD RAIN WITH EMBEDDED THUNDERSTORMS WILL CONTINUE TO
IMPACT ALL NRN LWR MICHIGAN TAF SITES THIS AFTERNOON AND INTO
EARLY EVENING AS A VIGOROUS WAVE SLIDES THRU THE AREA AHEAD OF AN
APPROACHING COLD FRONT. OVERALL CONDITIONS WILL REMAIN IFR...WITH
SOME BRIEF MOMENTS OF MVFR CONDITIONS. ALL PRECIP SHOULD END BY
AROUND 00Z THIS EVENING. ANY AMOUNT OF CLEARING AFTER THE PRECIP
ENDS WILL VERY TEMPORARY AS AREAS OF FOG AND STRATUS REDEVELOP
LATER THIS EVENING AND OVERNIGHT THANKS TO AMPLE LOW LEVEL
MOISTURE LINGERING BEHIND THE FRONT. CONDITIONS SHOULD RETURN TO
VFR WEDNESDAY MORNING AS MUCH DRIER LOW LEVEL AIR PUSHES INTO THE
REGION AND DIURNAL MIXING LENDS A HAND AS WELL.
&&
.MARINE...
ISSUED AT 431 AM EDT TUE SEP 8 2015
TODAY/TONIGHT...LIGHT WINDS TODAY AND TONIGHT...ONLY MARINE ISSUE
WILL BE POOR VISIBILITY IN FOG.
OUTLOOK...WINDS WILL PICK UP FROM THE NORTHWEST WEDNESDAY BEHIND A
COLD FRONT CROSSING THE UPPER LAKES TUESDAY NIGHT. WINDS WILL BE
GUSTY WITHIN NORTHERN LAKE HURON ZONES WITH COASTAL CONVERGENCE...
MAY BE CLOSE TO SMALL CRAFT CRITERIA.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...MLR
NEAR TERM...JPB
SHORT TERM...JSL
LONG TERM...JSL
AVIATION...MLR
MARINE...JPB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1232 PM EDT TUE SEP 8 2015
LATEST UPDATE...
MARINE
.SYNOPSIS...
ISSUED AT 329 AM EDT TUE SEP 8 2015
PERIODS OF SHOWERS AND THUNDERSTORMS WILL PREVAIL TODAY INTO THIS
EVENING BEFORE A SLOW MOVING COLD FRONT PUSHES THEM SOUTH OF THE
AREA BY MID MORNING WEDNESDAY. AREAS OF LOCALIZED HEAVY RAINFALL
ARE POSSIBLE. IT WILL CONTINUE TO BE VERY HUMID TODAY BUT NOT
QUIET AS WARM AS THE PAST FEW DAY. COOLER AND SIGNIFICANTLY DRIER
AIR WILL FOLLOW THE COLD FRONT FOR WEDNESDAY AND SUNSHINE SHOULD
PREVAIL IN MOST AREAS BY MID AFTERNOON. A SECONDARY COLD FRONT
WILL COME THROUGH THE AREA ON FRIDAY WITH SCATTERED SHOWERS. THIS
COMING WEEKEND SHOULD BE MOSTLY CLEAR WITH MUCH COOLER
TEMPERATURES...HIGHS MAY ONLY REACH THE MID 60S ON SATURDAY.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 329 AM EDT TUE SEP 8 2015
OUR PRIMARY ISSUE CONTINUES TO BE THE THREAT FOR HEAVY RAINFALL.
PRECIPITABLE WATER CONTINUES TO RUN BETWEEN 1.8 AND 2.0 INCHES
OVER MOST OF THE CWA TODAY. THIS IS AROUND 3 TIMES NORMAL AND IS
APPROACHING ALL TIME RECORD VALUES FOR THIS TIME OF YEAR. ADD TO
THAT A FRONTAL BOUNDARY SLOWLY MOVING THROUGH THE AREA...AIDED BY
THE ENTRANCE REGION OF THE POLAR JET AND A SHORTWAVE FROM IOWA...
AND THERE IS LITTLE QUESTION SOME OF THE STORMS WILL PRODUCE
HEAVY RAINFALL. CORFIDI VECTORS WILL BE BELOW 10 MILE PER HOUR
THIS MORNING AND RISE TO AROUND 15 MPH THIS AFTERNOON. THAT TOO
WILL AID IN THE LOCALLY HEAVY RAINFALL. I STILL BELIEVE SOME
ISOLATED RAINFALL AMOUNTS MAY BE CLOSE TO 5 INCHES FROM THIS
EVENT.
WE HAVE THE REMAINS OF YESTERDAYS OUTFLOW BOUNDARY STALLED
BETWEEN I-94 AND I-96 EARLY THIS MORNING. AS THE SHORTWAVE FROM
IOWA MOVES CLOSER TO THIS AREA WILL BE THE FOCUS FOR CONVECTION
THIS MORNING. WHICH SUGGESTS THE STORMS WILL MOSTLY BE SOUTH OF
I-96 AT FIRST BUT THEN LIFT NORTHWARD WITH TIME. BY LATE MORNING
INTO EARLY AFTERNOON I WOULD EXPECT MOST OF THE CONVECTION TO BE
NORTH OF I-96. THEN AS THE PRIMARY COLD FRONT AND SHORTWAVE MOVE
INTO THE AREA.. THE RAP MODEL SHOWS A 30 - 35 KNOT LOW LEVEL JET
MOVING INTO THE AREA BY MID AFTERNOON. THE CORE OF THE SPEED MAX
WILL BE JUST NORTH OF I-96 AND BE EAST OF MKG BY 4 PM AND BE NORTH
OF LANSING BY 8 PM. THIS SUGGEST TO ME THE STRONGEST CONVECTION
WILL BE DURING THE LATE AFTERNOON AND EARLY EVENING.
THERE IS A MARGINAL RISK FOR SEVERE STORMS (SPC) TODAY... WITH THE
NARROW CAPE... AND NUMEROUS HEAVY SHOWERS AROUND... AND ONLY
MARGINAL DEEP LAYER SHEAR... I WOULD IMAGINE ANY SEVERE WEATHER
WOULD BE VERY ISOLATED TODAY.
ONCE THE COLD FRONT COMES THROUGH MOST OF THE CONVECTION WILL EXIT
WITH IT THIS EVENING. HIGH PRESSURE FOLLOWS FOR WEDNESDAY INTO
THURSDAY. CLEARING SKIES FROM NORTHWEST TO SOUTHEAST WEDNESDAY
AFTERNOON. I WOULD EXPECT MOSTLY CLEAR SKIES WEDNESDAY NIGHT INTO
THURSDAY AS THE HIGH MOVES OVERHEAD.
BOTTOM LINE IS WET TODAY...DRY WEDNESDAY AFTERNOON INTO THURSDAY
EVENING.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 329 AM EDT TUE SEP 8 2015
A NICE COOL DOWN IS EXPECTED BY THE END OF THE WEEK AS A DEEP UPPER
TROUGH DEVELOPS OVER THE GREAT LAKES. WE/LL SEE TEMPERATURES IN THE
60S FRIDAY THROUGH SUNDAY ALONG WITH SOME SHOWERS FRIDAY AND
SATURDAY. MODEL CONCERNS ARE SIMILAR TO YESTERDAY AS THE ECMWF
DEEPENS THE LOW AND THEN CUTS IT OFF OVER MICHIGAN SUNDAY WHILE THE
GFS KEEPS THE SYSTEM AN OPEN WAVE AND THEN SCOOTS IT EASTWARD BY
SUNDAY. THE GFS WOULD LEAD TO WARMER TEMPS AND LESS PCPN THAN THE
SLOWER COOLER ECMWF. WE/RE LEANING TOWARD THE GFS SOLUTION AS IT
ALSO LINES UP NICELY WITH THE LATEST FIM. THUS ANY SHOWERS SHOULD
END BY LATE SATURDAY LEADING TO DRY WX SUNDAY AND MONDAY AND WARMER
TEMPS AS RIDGING BUILDS INTO SW LWR MI.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 745 AM EDT TUE SEP 8 2015
CURRENTLY MOSTLY VFR CONDITIONS PREVAIL AT OUR TAF SITES. THERE
IS A BAND OF CONVECTION (WEST TO EAST) LIFTING NORTHWARD HEAD OF
THE SHORTWAVE COMING OUT OF IOWA. THIS BAND OF CONVECTION SHOULD
BE NORTH OF THE TAF STIES BY 16Z OR SO. THEN THE CONVECTION WITH
THE COLD FRONT WILL CROSS THE TAF SITES BETWEEN 22Z AND 03Z FROM
WEST TO EAST. SHOWERS WILL THEN PREVAIL FOR FEW HOURS ONCE THE
COLD FRONT IS THROUGH. ONCE THE SHOWERS END EXPECT A FEW HOURS OF
MVFR CIGS.
&&
.MARINE...
ISSUED AT 1224 PM EDT TUE SEP 8 2015
NEARSHORE BOUYS FROM GRAND HAVEN TO LUDINGTON SHOWING WAVES OF 2
TO 4 FEET. LOOKS LIKE THE WAVES ARE ASSOCIATED WITH AN AREA OF
ENHANCED SOUTH WINDS OF 15 TO 20 KTS AHEAD OF THE APPROACHING COLD
FRONT AND THUNDERSTORM ACTIVITY. LARGEST WAVES OF 4FT SHOULD
CONTINUE TO SPREAD NORTHWARD TOWARDS LUDINGTON WHILE WAVES SHOULD
BEGIN TO SUBSIDE SOUTH OF MUSKEGON.
STILL EXPECTING VISIBILITY BELOW 1 MILE IN SHOWERS AND
THUNDERSTORMS THIS AFTERNOON AND CONTINUING INTO THIS EVENING
SOUTH OF MUSKEGON. FIRST BATCH WILL MOVE ONSHORE BY 6PM WITH A
SECOND AREA OF SHOWERS AND FOG OVER SOUTH HALF OF THE LAKE
OVERNIGHT.
POSSIBLY SCA FOR WED WITH GUSTY WEST WINDS BEHIND COLD FRONT.
LOOKING FOR OCCASIONAL GUSTS TO 25 KTS AND BUILDING SEAS OF 3 TO 5
FEET THROUGH THE AFTERNOON.
&&
.HYDROLOGY...
ISSUED AT 1207 AM EDT TUE SEP 8 2015
A FLOOD ADVISORY IS ONGOING FOR HOLT ON THE SYCAMORE CREEK. THE
STAGE CONTINUES TO RISE...BUT THE RATE OF RISE IS NOT QUITE AS
STEEP AS IT WAS EARLIER THIS MORNING. CURRENT CRESTS THAT ARE
FORECAST WILL BE HIGHLY DEPENDENT ON TONIGHTS RAINFALL AMOUNTS.
A COMPLEX OF SHOWERS AND THUNDERSTORMS THAT DEVELOPED OVER THE
UPPER MIDWEST LATE LAST NIGHT CONTINUE TO PROGRESS NORTHEAST
THROUGH THE NORTHERN GREAT LAKES. A LINE OF SHOWERS AND
THUNDERSTORMS CURRENTLY EXTENDS FROM CENTRAL LAKE MICHIGAN AND
SOUTHWEST INTO ILLINOIS. THIS LINE CONTINUES TO EXPAND AS IT
PRESSES EASTWARD. FOR SOME LOCATIONS...THIS WILL BE THE SECOND
ROUND OF RAINFALL TODAY. HEAVY RAIN OF ONE TO TWO INCHES IS
POSSIBLE...ESPECIALLY IN OR NEAR THUNDERSTORMS.
ANOTHER WAVE OF PRECIPITATION MAY DEVELOP FURTHER SOUTH AND WEST
OVERNIGHT...ACROSS THE SOUTHERN HALF OF LOWER MICHIGAN...WHICH
COULD BRING ADDITIONAL PERIODS OF HEAVY RAIN. OVERALL RAINFALL
TOTALS COULD EXCEED TWO INCHES IN LOCATIONS AFFECTED BY REPEATED
EVENTS. LOCALIZED FLOODING TO URBAN AREAS AND PONDING OF ROADWAYS
COULD OCCUR DURING AND CLOSELY FOLLOWING HEAVY RAINFALL. AREAS
STREAMS AND RIVERS MAY RISE DUE TO QUICK RUNOFF AS MANY LOCATIONS
ALREADY HAVE SATURATED SOILS.
DRY WEATHER IS ANTICIPATED TO RETURN BY MID MORNING WEDNESDAY.
THIS SHOULD ALLOW RIVERS TIME TO STABILIZE WEDNESDAY INTO
THURSDAY.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...99
AVIATION...WDM
HYDROLOGY...JAM
MARINE...COBB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1207 PM EDT TUE SEP 8 2015
LATEST UPDATE...
HYDRO
.SYNOPSIS...
ISSUED AT 329 AM EDT TUE SEP 8 2015
PERIODS OF SHOWERS AND THUNDERSTORMS WILL PREVAIL TODAY INTO THIS
EVENING BEFORE A SLOW MOVING COLD FRONT PUSHES THEM SOUTH OF THE
AREA BY MID MORNING WEDNESDAY. AREAS OF LOCALIZED HEAVY RAINFALL
ARE POSSIBLE. IT WILL CONTINUE TO BE VERY HUMID TODAY BUT NOT
QUIET AS WARM AS THE PAST FEW DAY. COOLER AND SIGNIFICANTLY DRIER
AIR WILL FOLLOW THE COLD FRONT FOR WEDNESDAY AND SUNSHINE SHOULD
PREVAIL IN MOST AREAS BY MID AFTERNOON. A SECONDARY COLD FRONT
WILL COME THROUGH THE AREA ON FRIDAY WITH SCATTERED SHOWERS. THIS
COMING WEEKEND SHOULD BE MOSTLY CLEAR WITH MUCH COOLER
TEMPERATURES...HIGHS MAY ONLY REACH THE MID 60S ON SATURDAY.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 329 AM EDT TUE SEP 8 2015
OUR PRIMARY ISSUE CONTINUES TO BE THE THREAT FOR HEAVY RAINFALL.
PRECIPITABLE WATER CONTINUES TO RUN BETWEEN 1.8 AND 2.0 INCHES
OVER MOST OF THE CWA TODAY. THIS IS AROUND 3 TIMES NORMAL AND IS
APPROACHING ALL TIME RECORD VALUES FOR THIS TIME OF YEAR. ADD TO
THAT A FRONTAL BOUNDARY SLOWLY MOVING THROUGH THE AREA...AIDED BY
THE ENTRANCE REGION OF THE POLAR JET AND A SHORTWAVE FROM IOWA...
AND THERE IS LITTLE QUESTION SOME OF THE STORMS WILL PRODUCE
HEAVY RAINFALL. CORFIDI VECTORS WILL BE BELOW 10 MILE PER HOUR
THIS MORNING AND RISE TO AROUND 15 MPH THIS AFTERNOON. THAT TOO
WILL AID IN THE LOCALLY HEAVY RAINFALL. I STILL BELIEVE SOME
ISOLATED RAINFALL AMOUNTS MAY BE CLOSE TO 5 INCHES FROM THIS
EVENT.
WE HAVE THE REMAINS OF YESTERDAYS OUTFLOW BOUNDARY STALLED
BETWEEN I-94 AND I-96 EARLY THIS MORNING. AS THE SHORTWAVE FROM
IOWA MOVES CLOSER TO THIS AREA WILL BE THE FOCUS FOR CONVECTION
THIS MORNING. WHICH SUGGESTS THE STORMS WILL MOSTLY BE SOUTH OF
I-96 AT FIRST BUT THEN LIFT NORTHWARD WITH TIME. BY LATE MORNING
INTO EARLY AFTERNOON I WOULD EXPECT MOST OF THE CONVECTION TO BE
NORTH OF I-96. THEN AS THE PRIMARY COLD FRONT AND SHORTWAVE MOVE
INTO THE AREA.. THE RAP MODEL SHOWS A 30 - 35 KNOT LOW LEVEL JET
MOVING INTO THE AREA BY MID AFTERNOON. THE CORE OF THE SPEED MAX
WILL BE JUST NORTH OF I-96 AND BE EAST OF MKG BY 4 PM AND BE NORTH
OF LANSING BY 8 PM. THIS SUGGEST TO ME THE STRONGEST CONVECTION
WILL BE DURING THE LATE AFTERNOON AND EARLY EVENING.
THERE IS A MARGINAL RISK FOR SEVERE STORMS (SPC) TODAY... WITH THE
NARROW CAPE... AND NUMEROUS HEAVY SHOWERS AROUND... AND ONLY
MARGINAL DEEP LAYER SHEAR... I WOULD IMAGINE ANY SEVERE WEATHER
WOULD BE VERY ISOLATED TODAY.
ONCE THE COLD FRONT COMES THROUGH MOST OF THE CONVECTION WILL EXIT
WITH IT THIS EVENING. HIGH PRESSURE FOLLOWS FOR WEDNESDAY INTO
THURSDAY. CLEARING SKIES FROM NORTHWEST TO SOUTHEAST WEDNESDAY
AFTERNOON. I WOULD EXPECT MOSTLY CLEAR SKIES WEDNESDAY NIGHT INTO
THURSDAY AS THE HIGH MOVES OVERHEAD.
BOTTOM LINE IS WET TODAY...DRY WEDNESDAY AFTERNOON INTO THURSDAY
EVENING.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 329 AM EDT TUE SEP 8 2015
A NICE COOL DOWN IS EXPECTED BY THE END OF THE WEEK AS A DEEP UPPER
TROUGH DEVELOPS OVER THE GREAT LAKES. WE/LL SEE TEMPERATURES IN THE
60S FRIDAY THROUGH SUNDAY ALONG WITH SOME SHOWERS FRIDAY AND
SATURDAY. MODEL CONCERNS ARE SIMILAR TO YESTERDAY AS THE ECMWF
DEEPENS THE LOW AND THEN CUTS IT OFF OVER MICHIGAN SUNDAY WHILE THE
GFS KEEPS THE SYSTEM AN OPEN WAVE AND THEN SCOOTS IT EASTWARD BY
SUNDAY. THE GFS WOULD LEAD TO WARMER TEMPS AND LESS PCPN THAN THE
SLOWER COOLER ECMWF. WE/RE LEANING TOWARD THE GFS SOLUTION AS IT
ALSO LINES UP NICELY WITH THE LATEST FIM. THUS ANY SHOWERS SHOULD
END BY LATE SATURDAY LEADING TO DRY WX SUNDAY AND MONDAY AND WARMER
TEMPS AS RIDGING BUILDS INTO SW LWR MI.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 745 AM EDT TUE SEP 8 2015
CURRENTLY MOSTLY VFR CONDITIONS PREVAIL AT OUR TAF SITES. THERE
IS A BAND OF CONVECTION (WEST TO EAST) LIFTING NORTHWARD HEAD OF
THE SHORTWAVE COMING OUT OF IOWA. THIS BAND OF CONVECTION SHOULD
BE NORTH OF THE TAF STIES BY 16Z OR SO. THEN THE CONVECTION WITH
THE COLD FRONT WILL CROSS THE TAF SITES BETWEEN 22Z AND 03Z FROM
WEST TO EAST. SHOWERS WILL THEN PREVAIL FOR FEW HOURS ONCE THE
COLD FRONT IS THROUGH. ONCE THE SHOWERS END EXPECT A FEW HOURS OF
MVFR CIGS.
&&
.MARINE...
ISSUED AT 329 AM EDT TUE SEP 8 2015
WINDS AND WAVES SHOULD REMAIN BELOW SMALL CRAFT CRITERIA THROUGH
THURSDAY. EVEN SO THERE MAY BE GUSTY WINDS IN SOME OF THE
THUNDERSTORMS TODAY. VISIBILITIES MAY BE REDUCED TO BELOW A HALF
MILE IN SOME OF THE HEAVY THUNDERSTORMS TODAY.
&&
.HYDROLOGY...
ISSUED AT 1207 AM EDT TUE SEP 8 2015
A FLOOD ADVISORY IS ONGOING FOR HOLT ON THE SYCAMORE CREEK. THE
STAGE CONTINUES TO RISE...BUT THE RATE OF RISE IS NOT QUITE AS
STEEP AS IT WAS EARLIER THIS MORNING. CURRENT CRESTS THAT ARE
FORECAST WILL BE HIGHLY DEPENDENT ON TONIGHTS RAINFALL AMOUNTS.
A COMPLEX OF SHOWERS AND THUNDERSTORMS THAT DEVELOPED OVER THE
UPPER MIDWEST LATE LAST NIGHT CONTINUE TO PROGRESS NORTHEAST
THROUGH THE NORTHERN GREAT LAKES. A LINE OF SHOWERS AND
THUNDERSTORMS CURRENTLY EXTENDS FROM CENTRAL LAKE MICHIGAN AND
SOUTHWEST INTO ILLINOIS. THIS LINE CONTINUES TO EXPAND AS IT
PRESSES EASTWARD. FOR SOME LOCATIONS...THIS WILL BE THE SECOND
ROUND OF RAINFALL TODAY. HEAVY RAIN OF ONE TO TWO INCHES IS
POSSIBLE...ESPECIALLY IN OR NEAR THUNDERSTORMS.
ANOTHER WAVE OF PRECIPITATION MAY DEVELOP FURTHER SOUTH AND WEST
OVERNIGHT...ACROSS THE SOUTHERN HALF OF LOWER MICHIGAN...WHICH
COULD BRING ADDITIONAL PERIODS OF HEAVY RAIN. OVERALL RAINFALL
TOTALS COULD EXCEED TWO INCHES IN LOCATIONS AFFECTED BY REPEATED
EVENTS. LOCALIZED FLOODING TO URBAN AREAS AND PONDING OF ROADWAYS
COULD OCCUR DURING AND CLOSELY FOLLOWING HEAVY RAINFALL. AREAS
STREAMS AND RIVERS MAY RISE DUE TO QUICK RUNOFF AS MANY LOCATIONS
ALREADY HAVE SATURATED SOILS.
DRY WEATHER IS ANTICIPATED TO RETURN BY MID MORNING WEDNESDAY.
THIS SHOULD ALLOW RIVERS TIME TO STABILIZE WEDNESDAY INTO
THURSDAY.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...99
AVIATION...WDM
HYDROLOGY...JAM
MARINE...WDM
AREA FORECAST DISCUSSION
NWS DULUTH MN
1250 PM CDT TUE SEP 8 2015
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 331 AM CDT TUE SEP 8 2015
AT 330 AM...SKIES WERE PARTLY TO MOSTLY CLOUDY ACROSS THE
NORTHLAND. THERE WERE A FEW LIGHT RAIN SHOWERS OR SPRINKLES ACROSS
NW WI...WITH A LARGE AREA OF SHOWERS AND THUNDERSTORMS SOUTH AND
WEST OF THE CWA. TEMPERATURES RANGED FROM NEAR 50 ACROSS THE NORTH
TO THE LOWER 60S IN PORTIONS OF NW WI. WINDS WERE GENERALLY LIGHT.
THE MAIN FOCUS FOR TODAY WILL BE THE POTENTIAL FOR SHOWERS AND
THUNDERSTORMS...ESPECIALLY ACROSS NW WI. THE RAP SEEMS TO HAVE THE
BEST HANDLE ON THE CURRENT TRENDS ACROSS THE UPPER MIDWEST. HAVE
INCREASED POPS ACROSS NW WI THIS MORNING AND WILL HAVE TO KEEP A
CLOSE EYE ON THE CONVECTION STREAMING NORTHEAST FROM SOUTHERN MN.
MAY NEED TO INCREASE POPS EVEN FURTHER DEPENDING ON THE EVOLUTION
OF THE COMPLEX TO OUR SOUTH AS A SHORTWAVE LIFTS TO THE NORTH AND
EAST DURING THE MORNING. THE CHANCE OF PRECIPITATION WILL
GENERALLY INCREASE OVERNIGHT AND EARLY TODAY...AND THEN DECREASE
FROM LATE MORNING THROUGH THIS AFTERNOON. SKIES SHOULD BECOME
PARTLY TO MOSTLY SUNNY ACROSS THE AREA. HIGHS WILL BE IN THE 70S.
WITH CLEAR TO PARTLY CLOUDY SKIES AND HIGH PRESSURE SETTING IN
TONIGHT...WE SHOULD SEE OVERNIGHT LOWS LARGELY IN THE 40S.
WEST TO NORTHWEST FLOW ON WEDNESDAY WILL BRING A COUPLE AREAS OF
POSSIBLE PRECIPITATION AS THE DAY WEARS ON. THE FIRST WILL BE
ACROSS THE NORTH...AS A COLD FRONT DROPS SOUTHWARD ACROSS THE
INTERNATIONAL BORDER. ANOTHER WILL BE FURTHER SOUTH FROM EAST
CENTRAL MN INTO NORTHERN WISCONSIN...AS SHOWERS AND POSSIBLY EVEN
SOME THUNDERSTORMS DEVELOP IN THE AFTERNOON. THE COLD FRONT SHOULD
BE GENERALLY ACROSS THAT AREA BY LATE IN THE DAY. TEMPS WILL BE A
BIT COOLER ON WEDNESDAY...RANGING FROM THE MID 60S NORTH TO THE
LOWER TO MIDDLE 70S SOUTH.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 331 AM CDT TUE SEP 8 2015
THE UPPER PATTERN WILL FEATURE AN UPPER LOW OVER HUDSON BAY EARLY IN
THE PERIOD WITH A TROUGH EXTENDING SOUTH INTO THE NORTHLAND. THE LOW
WILL MOVE EAST THROUGH THE PERIOD WITH NORTHWEST FLOW DEVELOPING.
FINALLY LATE IN THE WEEKEND/EARLY NEXT WEEK THE FLOW WILL BECOME
MORE ZONAL.
SEVERAL SHORTWAVES WILL MOVE THROUGH THE REGION BRINGING A CHANCE
FOR SHOWERS AND PERHAPS A THUNDERSTORM WEDNESDAY NIGHT THROUGH
FRIDAY AND AGAIN MONDAY/TUESDAY. AT THIS TIME...THESE SYSTEMS DO NOT
LOOK PARTICULARLY STRONG WITH THE EXCEPTION OF WEDNESDAY
NIGHT/THURSDAY. THE ECMWF IS SHOWING HIGHER RAINFALL OVER OUR
SOUTHERN ZONES WHICH IS NOT OUT OF THE QUESTION AS THERE SHOULD BE
SOME FGEN FORCING AS THE UPPER WAVE MOVES THROUGH. WE INCREASED POPS
OVER SOUTHERN AREAS A BIT...AND MAY HAVE TO INCREASE QUITE A BIT IF
BETTER AGREEMENT OCCURS AMONG THE MODELS.
TEMPERATURES WILL BE A FEW DEGREES COOLER THAN NORMAL
THURSDAY/FRIDAY/SATURDAY...THEN MODERATE BRIEFLY SUNDAY BEFORE
FALLING BELOW NORMAL AGAIN BY TUESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1226 PM CDT TUE SEP 8 2015
HIGH PRESSURE BUILDING IN FROM THE WEST WITH MUCH DRIER AIR WILL
ALLOW FOR GENERALLY VFR CONDITIONS THROUGH THE NEXT 24 HRS. A MID
LEVEL BAND OF CUMULUS WILL DEVELOP AND PASS THROUGH THIS
AFTERNOON AND EVENING...BUT WILL DISSIPATE THROUGH THE OVERNIGHT
AND LEAVE MOSTLY CLEAR SKIES THROUGH THE NIGHT. THE AIR MASS
SHOULD BE DRY ENOUGH AND WINDS WILL REMAIN VARIABLE AROUND 5
KTS...WHICH WILL KEEP WIDESPREAD FOG FROM FORMING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 74 49 71 50 / 10 0 20 20
INL 69 43 66 40 / 10 10 20 20
BRD 74 48 73 49 / 10 0 20 30
HYR 77 44 73 49 / 60 0 30 30
ASX 79 48 75 49 / 30 0 20 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...NONE.
&&
$$
SHORT TERM...DAP
LONG TERM...MELDE
AVIATION...TENTINGER
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
935 AM PDT TUE SEP 8 2015
.SYNOPSIS...HIGH PRESSURE ALOFT WILL BUILD NORTHWEST AND BECOME
CENTERED OVER THE MOJAVE DESERT THROUGH SATURDAY. THIS WILL RESULT
IN ABOVE NORMAL TEMPERATURES. MOIST AND UNSTABLE AIR WILL RESULT IN
THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS TODAY THROUGH THURSDAY
MAINLY IN THE AFTERNOON AND EVENING HOURS SOUTH OF INTERSTATE 40.
AFTER MAINLY DRY CONDITIONS ON FRIDAY AND SATURDAY AN AREA OF LOW
PRESSURE APPROACHING NORTHERN CALIFORNIA MAY SPARK OFF AN ISOLATED
SHOWER OR THUNDERSTORM ON SUNDAY IN THE HIGHER ELEVATIONS OF THE
MOJAVE DESERT.
&&
.UPDATE...CURRENT MESOANALYSIS INDICATED FAIRLY UNSTABLE AIR ACROSS
SOUTHEAST SAN BERNARDINO AND SOUTHERN MOHAVE COUNTIES AN ALSO NOSING
UP INTO NORTHERN MOHAVE COUNTY. THE LATEST NAM12 AND HRRR INDICATE
MOISTURE AND INSTABILITY PERSISTING ACROSS NORTHERN MOHAVE COUNTY
THIS AFTERNOON WHERE WE WERE NOT FORECASTING ANY THUNDERSTORMS. I
UPDATED TO INCREASE POPS AND MENTION THUNDERSTORMS IN THAT AREA FOR
THIS AFTERNOON AND EVENING. OTHERWISE THE FORECAST LOOKS GOOD AND NO
OTHER UPDATES ARE PLANNED. -HARRISON-
&&
.PREV DISCUSSION...
308 AM PDT TUE SEP 8 2015
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT.
FOR THE THIRD MORNING IN A ROW, A FEW SHOWERS AND THUNDERSTORMS HAVE
POPPED UP IN AN AREA OF MID-LEVEL CONVERGENCE BETWEEN THE WASHED OUT
MID/UPPER LEVEL TROUGH AXIS OVER SOUTHERN NEVADA AND THE EXIT REGION
OF A 250 MB JET STREAK LOCATED OVER ARIZONA AND SOUTHEAST
CALIFORNIA. THIS ACTIVITY WAS OVER THE PLATEAU REGION OF MOHAVE
COUNTY AS WELL AS IN THE JEAN/PRIMM/GOODSPRINGS AREA. THIS SHOULD
DIMINISH IN THE NEXT FEW HOURS.
HIGH PRESSURE ALOFT LOCATED NEAR EL PASO WILL BEGIN TO EXPAND
NORTHWEST TOWARD OUR AREA TODAY. THIS WILL RESULT IN ABOVE NORMAL
TEMPERATURES WITH READINGS JUMPING UP ANOTHER DEGREE OR TWO TODAY
FROM WHAT WAS OBSERVED ON LABOR DAY. THE EAST TO SOUTHEAST FLOW IN
THE MID-LEVELS AROUND THE HIGH WILL HELP TO SLOSH MOISTURE BACK TO
THE WEST TODAY. THE HRRR, ARW, NMM, WRF, GFS AND ECMWF ALL SHOW
SIMILAR TRENDS WITH THIS THOUGH VARY WIDELY WITH QPF DEVELOPMENT.
PWATS ACROSS THE MOJAVE DESERT WILL MAINLY BE BETWEEN 0.75 INCH AND
1.00 INCH. HOWEVER, A WARM LAYER ALOFT WILL KEEP MOST OF THE AREA
CAPPED AND THUS STABLE WITH THE RESULT JUST BEING CUMULUS. ALONG AND
SOUTH OF I-40 THE CAP MAY BE ABLE TO BREAK AND ALLOW FOR SHOWERS AND
THUNDERSTORMS TO GET GOING ESPECIALLY ONCE THE CONVECTIVE
TEMPERATURE OF 104 IS REACHED. THE 700 MB FLOW TODAY IS VARIABLE
ACROSS THE AREA SO STORMS WILL BE SLOWER MOVING COMPARED TO RECENT
DAYS. ONE AREA TO WATCH WILL BE IN SOUTHERN CLARK AND NORTHEAST SAN
BERNARDINO COUNTY WHERE THE STEERING FLOW IS WESTERLY AND WE MAY SEE
ACTIVITY MAKE A RUN TOWARD THE COLORADO RIVER VALLEY. THE HRRR AND
WRF ARE BOTH QUITE ACTIVE IN THIS AREA THIS AFTERNOON AS WELL AS IN
THE MORONGO BASIN. AS A RESULT, I INCREASED POPS ACROSS THE SOUTHERN
TIER OF THE AREA TODAY. THE MAIN THREATS WILL BE FLASH FLOODING WITH
ANY STRONGER OR SLOWER MOVING STORMS AS WELL AS GUSTY AND ERRATIC
WINDS AND BLOWING DUST.
THE ROUGH FIRE NEAR HUME LAKE, CA GREW IN SIZE YESTERDAY AND
VISIBILITY IN BISHOP WAS ALREADY BACK DOWN TO 6 MILES. THE WINDS
ALOFT ARE WEAKER IN THIS AREA BUT IF THE FIRE CRANKS UP AGAIN TODAY
WITH THE HEATING OF THE DAY, WE MAY AGAIN SEE EXTENSIVE SMOKE AND
HAZE INTO NORTHERN INYO COUNTY. THIS MAY STAY LOFTED DURING THE DAY
AS SURFACE WINDS PICK UP IN THE AFTERNOON BUT AS WINDS DROP OFF AT
NIGHT, THE SMOKE SHOULD SETTLE BACK DOWN AND DROP VISIBILITY ONCE
AGAIN.
THE AFOREMENTIONED HIGH IS SLATED TO BUILD NORTHWEST INTO THE MOJAVE
DESERT AND BECOME CENTERED OVERHEAD BY THURSDAY. THIS WILL TRAP
WHATEVER MOISTURE IS IN PLACE UNDERNEATH. FOR AREAS NORTH OF I-40,
WE SHOULD REMAIN CAPPED AND AT BEST SEE A FEW CUMULUS POP UP.
HOWEVER, ACROSS THE SOUTHERN TIER OF THE AREA, THE CAP WILL NOT BE
AS STRONG, AND SHOWERS AND THUNDERSTORMS WILL HAVE BETTER CHANCE TO
DEVELOP FROM THE MORONGO BASIN EAST TO WIKIEUP AND PERHAPS AS FAR
NORTH AS LUDLOW, THE MOJAVE NATIONAL PRESERVE, SEARCHLIGHT AND
KINGMAN. PWATS ARE SHOWN TO INCREASE TO NEAR 1.50 INCH BY WEDNESDAY
AND THURSDAY NEAR VIDAL JUNCTION AND LAKE HAVASU AS ADDITIONAL
MOISTURE GETS PUSHED NORTH FROM WHAT MAY BE A SURGE TRIGGERED BY
PACIFIC HURRICANE LINDA. THIS WILL INCREASE THE FLASH FLOOD THREAT
WITH STORMS AS THEY WILL HAVE A GREATER UNLOAD FACTOR. TEMPS WILL
TREND UP FURTHER IN AREAS FREE OF STORMS, HOWEVER, WHERE CLOUDS ARE
GREATER AND STORMS ARE AROUND TEMPS WILL ACTUALLY DROP A FEW
DEGREES. SMOKE ISSUES IN INYO COUNTY FROM THE ROUGH FIRE WILL NOT GO
AWAY EITHER AS THE WINDS ALOFT REMAIN WEAK AND MAY FAVOR MORE OF A
WESTERLY DIRECTION AGAIN BY THURSDAY.
.LONG TERM...FRIDAY THROUGH TUESDAY.
THE OVERALL PATTERN IS LOOKING SOMEWHAT INTERESTING THIS WEEKEND
INTO EARLY NEXT WEEK. FRIDAY STARTS OFF WITH A STRONG RIDGE CENTERED
ALMOST DIRECTLY OVER THE FORECAST AREA WHICH WILL PROVIDE HIGH TEMPS
OF 105-110 DEGREES OVER MUCH OF THE MOJAVE DESERT REGION.
MEANWHILE...REMNANT MOISTURE FROM LINDA IS FORECAST TO BE PULLED UP
ALONG THE CALIFORNIA COAST ON THE WEST SIDE OF THE RIDGE. THE LATEST
GFS AND ECMWF SOLUTIONS ARE IN GOOD AGREEMENT WITH NUDGING THE RIDGE
TO THE SOUTHEAST OVER ARIZONA SATURDAY INTO SUNDAY BY A WEAK LOW
PRESSURE SYSTEM MOVING INTO THE NORTHERN/CENTRAL CALIFORNIA COAST.
THIS LOW ALSO DIRECTS MOISTURE INLAND ACROSS SOUTHERN CALIFORNIA AND
THE MOJAVE DESERT REGION SUNDAY INTO MONDAY. SLIGHT CHANCE POPS
WHERE INTRODUCED TO THE HIGHER TERRAIN SUNDAY AS MOISTURE BEGINS TO
MOVE INTO THE FORECAST AREA.
THE LOW IS FORECAST TO CLOSE OFF AND CIRCULATE ALONG THE CENTRAL
CALIFORNIA COAST MONDAY WHICH WOULD LEAD TO DIFFLUENT FLOW COMBINING
WITH MODERATE MOISTURE AND INSTABILITY OVER SOUTHERN NEVADA AND
NORTHWEST ARIZONA FOR AT LEAST A SLIGHT CHANCE OF THUNDERSTORMS BY
MONDAY AFTERNOON. TEMPERATURES WILL ALSO TREND DOWNWARD SUNDAY
ONWARD WITH MORE CLOUD COVER AND THE INFLUENCE OF THE COASTAL LOW.
THE GFS AND ECMWF SOLUTIONS DIVERGE WITH RESPECT TO WHAT HAPPENS
WITH THE COASTAL LOW AFTER MONDAY AND CONFIDENCE IS LOW IN ANY
DETAILS AFTER THAT.
&&
.AVIATION...FOR MCCARRAN...WINDS WILL AGAIN FAVOR TYPICAL DIURNAL
TRENDS THROUGH TONIGHT. BETWEEN 15Z TODAY AND 00Z WEDNESDAY WINDS
WILL FAVOR AN EASTERLY COMPONENT INITIALLY FROM THE NORTHEAST THEN
MORE FROM THE SOUTHEAST AT 4-8 KTS WHICH MAY CAUSE CONFIGURATION
ISSUES. BY 04Z WEDNESDAY WINDS SHOULD MORE FIRMLY STAY OUT OF THE
SOUTH. FEW-SCT CLOUDS AOA 10K FEET.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...WINDS WILL MAINLY FAVOR TYPICAL DIURNAL DIRECTIONS
THROUGH TONIGHT. ISOLATED SHRA/TSRA ARE POSSIBLE TODAY MAINLY AFTER
18Z ALONG AND SOUTH OF A LINE FROM ROUGHLY KNXP-KIFP-KIGM. GUSTY AND
ERRATIC WINDS ARE POSSIBLE IN AND NEAR ANY SHRA/TSRA. SCT-BKN CLOUDS
AOA 7K-12K FEET AS WELL ALONG AND SOUTH OF A LINE FROM KDAG-KHND-
KIGM. AREAS OF FU AND HZ ARE POSSIBLE IN AROUND KBIH REDUCING VSBY
AND CREATING LOCAL MOUNTAIN OBSCURATIONS.
&&
.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 BUFFALO NY
231 PM EDT TUE SEP 8 2015
.SYNOPSIS...
HIGH PRESSURE OVER THE MID ATLANTIC COAST WILL CONTINUE TO BRING
MIDSUMMERLIKE CONDITIONS TO THE REGION THROUGH THE FIRST HALF OF
WEDNESDAY...BEFORE A COLD FRONT CROSSES OUR REGION BETWEEN LATER
WEDNESDAY AND WEDNESDAY NIGHT. THIS FRONT WILL BE ACCOMPANIED BY
NUMEROUS SHOWERS AND THUNDERSTORMS AS IT PASSES THROUGH...AND WILL
BE FOLLOWED BY PROGRESSIVELY COOLER WEATHER DURING THE REMAINDER
OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
DURING THE COURSE OF TODAY...THE WEAK COLD FRONT WILL BRIEFLY STALL
OUT ALONG OR SLIGHTLY NORTH OF OUR NORTHERN PERIPHERY THIS
MORNING... BEFORE LIFTING BACK NORTH THIS AFTERNOON AS A WARM FRONT
IN RESPONSE TO THE DEVELOPMENT OF BROAD LOW PRESSURE OVER THE UPPER
GREAT LAKES. ALONG AND NEAR THIS BOUNDARY...THERE WILL BE A
CONTINUED RISK OF SHOWERS AND THUNDERSTORMS THROUGH THE DAY...WITH
THIS RISK LYING ROUGHLY FROM THE NYS THRUWAY CORRIDOR NORTHWARD
THROUGH LATE THIS MORNING...THEN DIMINISHING FROM SOUTHWEST TO
NORTHEAST LATE THIS MORNING AND THIS AFTERNOON AS THE FRONT BEGINS
LIFTING BACK NORTH.
IN ADDITION TO ANY FRONTAL CONVECTION...THE COMBINATION OF DIURNAL
HEATING OF OUR VERY WARM AND HUMID AIRMASS AND REDEVELOPING LAKE
BREEZE BOUNDARIES MAY ALSO LEAD TO THE DEVELOPMENT OF A SECOND
REGION OF ISOLATED TO SCATTERED CONVECTION ACROSS AREAS SOUTH OF
LAKE ONTARIO THIS AFTERNOON...WITH THIS PRIMARILY FOCUSED FROM
INTERIOR PORTIONS OF THE SOUTHERN TIER AND GENESEE VALLEY EASTWARD
ACROSS THE FINGER LAKES.
WITH ALL OF THE ABOVE IN MIND...HAVE CONTINUED TO DEPICT A GENERAL
SOUTHWEST-NORTHEAST GRADIENT IN PRECIPITATION PROBABILITIES FOR
TODAY...WITH THESE RANGING FROM HIGH CHANCE TO LOW LIKELY FROM
LAKE ONTARIO EASTWARD ACROSS THE SAINT LAWRENCE VALLEY AND NORTH
COUNTRY...TO BELOW SLIGHT CHANCE IN AN EXPECTED REGION OF LAKE
SHADOWING IMMEDIATELY EAST OF LAKE ERIE.
OUTSIDE OF THE AFOREMENTIONED CONVECTION...DRY WEATHER AND
MIDSUMMERLIKE WARMTH AND HUMIDITY SHOULD AGAIN PREVAIL ACROSS OUR
REGION TODAY. SURFACE DEWPOINTS WILL RANGE FROM THE LOWER 60S
ACROSS INTERIOR PORTIONS OF THE SOUTHERN TIER TO NEAR 70 ALONG
THE STALLED/RETREATING FRONTAL BOUNDARY...WHILE 850 MB TEMPS OF
+16C TO +19C WILL SUPPORT HIGH TEMPERATURES RANGING FROM THE LOWER
80S ACROSS THE NORTH COUNTRY TO THE MID AND UPPER 80S ACROSS MOST
OF THE REST OF THE REGION...ALONG WITH SOME 90 DEGREE READINGS
ACROSS THE NORMAL WARM SPOTS OF THE GENESEE VALLEY/FINGER LAKES.
TONIGHT...THE WARM FRONT WILL FINISH LIFTING OFF TO OUR NORTH EARLY
IN THE EVENING. WITH THE DEPARTURE OF THIS FEATURE AND THE LOSS
OF DAYTIME HEATING...ANY LINGERING CONVECTION ACROSS THE FINGER LAKES
AND NORTH COUNTRY WILL COME TO AN END THIS EVENING...LEAVING BEHIND
LARGELY DRY WEATHER FOR THE BALANCE OF THE NIGHTTIME HOURS AS OUR
REGION WILL BE FIRMLY ENTRENCHED WITHIN THE WARM SECTOR OF LOW
PRESSURE LIFTING BY WELL TO OUR NORTHWEST. THUS...WE CAN EXPECT YET
ANOTHER UNSEASONABLY WARM NIGHT ACROSS OUR REGION...WITH OVERNIGHT
LOWS AGAIN RANGING FROM THE MID 60S ACROSS INTERIOR PORTIONS OF THE
SOUTHERN TIER TO THE LOWER 70S ACROSS THE LAKE PLAINS...OR LEVELS
THAT WILL BE NOT THAT FAR OFF FROM NORMAL HIGH TEMPERATURES FOR
EARLY SEPTEMBER.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
TEMPERATURES WILL RETURN TO NEAR NORMAL LEVELS ACROSS THE LOWER
GREAT LAKES DURING THIS PERIOD...AS THE UPPER LEVEL FLOW ACROSS
NORTH AMERICA WILL FEATURE AN AMPLIFYING TROUGH OVER THE EASTERN
HALF OF THE CONTINENT. THIS WILL BE SIGNIFICANT CHANGE FROM THE
FIRST WEEK OF SEPTEMBER WHEN A PERSISTENT SUB-TROPICAL RIDGE
DOMINATED THE EASTERN HALF OF THE COUNTRY. WHILE THE RIDGE WAS NOT
OVERLY IMPRESSIVE `ON PAPER`...ITS STAYING POWER FOR THIS TIME OF
YEAR ALLOWED FOR ANOMALOUSLY WARM AIR AND PLENTY OF GULF HUMIDITY
TO CREATE THE WARMEST STRETCH OF WEATHER OUR REGION EXPERIENCED
ALL SUMMER. WITH THE PASSING OF THE LAST SUMMER HOLIDAY...MOTHER
NATURE WILL ALSO TURN THE PAGE...ALBEIT IT SLOWLY.
AS IS SO OFTEN IS THE CASE...A STRONG LATITUDINAL H25 JET
CROSSING THE NORTHERN PACIFIC WILL PLOW ACROSS THE CANADIAN
ROCKIES AND ESTABLISH A BROAD DOWNSTREAM TROUGH OVER THE EASTERN
HALF OF THE CONTINENT. THIS TROUGH WILL FLATTEN THE PERTINACIOUS
SUB TROPICAL RIDGE...AND IN TIME WILL DIRECT PROGRESSIVELY COOLER
CANADIAN AIR SOUTHWARDS ACROSS THE LOWER 48. THIS COOLING WILL
INITIALLY ONLY TAKE OUR TEMPERATURES BACK TOWARDS NORMAL...BUT AS
WE HEAD IN TO THE WEEKEND...WE COULD EXPERIENCE A DAY OR TWO OF
FALL LIKE CONDITIONS.
AN INVERTED SFC TROUGH EXTENDING FROM THE UPPER GREAT LAKES TO
THE CENTRAL PLAINS LATE TUESDAY NIGHT WILL GRADUALLY EVOLVE INTO A
LEGITIMATE...ALBEIT WAVY...COLD FRONT ON WEDNESDAY AS IT WILL PUSH
SOUTHEAST ACROSS THE LOWER GREAT LAKES. THE OVERALL SYNOPTIC
FORCING WITH THE SLOW MOVING FRONTAL BOUNDARY IS NOT BEING
ADVERTISED AS BEING ALL THAT IMPRESSIVE...BUT IT WILL BE ENOUGH IN
COMBINATION WITH THE MID SUMMER LIKE THERMODYNAMIC ENVIRONMENT TO
PRODUCE INCREASINGLY NUMEROUS SHOWERS AND POTENTIALLY STRONG
THUNDERSTORMS.
ADDRESSING THE FORMER FIRST...AS EARLIER MENTIONED THE FRONTAL
BOUNDARY WILL STILL BE TAKING SHAPE DURING THE DAY WEDNESDAY AS IT
WILL BE PUSHING INTO OUR FORECAST AREA. TRUE FRONTOGENETIC FORCING
FROM THE FRONT WILL THUS BE GENERALLY WEAK...ALTHOUGH HGT FALLS
AND A 120KT H25 JET OVER NORTHERN QUEBEC WILL ADD SOME LARGE SCALE
SYNOPTIC LIFT BY PLACING OUR FORECAST AREA UNDER RR QUAD OF THE
JET ENTRANCE REGION. THERMODYNAMICALLY...OUR WARM HUMID AIRMASS
WILL ALREADY BE UNSTABLE. SBCAPES WILL ALREADY BE IN THE HUNDREDS
AS WE OPEN THE DAY...AND DIMINISHING MORNING SUNSHINE WILL ONLY
ADD TO THIS INSTABILITY...PARTICULARLY OVER PARTS OF THE SRN TIER
AND FINGER LAKES REGIONS WHERE MUCAPES COULD APPROACH 2000 J/KG.
MEANWHILE A SWATH OF TROPICAL MOISTURE TO THE TUNE OF 2 INCH PWAT
VALUES WILL STREAM ACROSS OUR REGION ALONG AND AHEAD OF THE SFC
BOUNDARY...SO THIS IN COMBINATION WITH THE SYNOPTIC FORCING AND
INSTABILITY COULD RESULT IN TORRENTIAL DOWNPOURS WITH SOME OF THE
CONVECTION. FORTUNATELY...THE REGION IS PARCHED FROM A GENERAL
LACK OF RAINFALL FROM THE PAST MONTH OR SO...AND GUIDANCE IS
SUGGESTING THAT CORFIDI VECTORS WILL LENGTHEN AS THE FRONT
APPROACHES. THIS WILL LESSEN THE RISK FOR WIDESPREAD HYDRO RELATED
PROBLEMS...BUT LOCAL ISSUES WILL STILL HAVE TO BE ADDRESSED GIVEN
THE SUB TROPICAL ENVIRONMENT. THE MENTION OF TORRENTIAL DOWNPOURS
HAS ALREADY BEEN ADDED TO THE HWO PRODUCT AND TO THE GRIDDED DATA
BASE...SO WILL CONTINUE.
ALONG WITH THE THREAT FOR LOCALLY HEAVY CONVECTIVE RAINS...THERE
WILL BE AN ISOLATED RISK FOR STRONG THUNDERSTORMS. THIS POTENTIAL
WILL BE ATTENUATED BY UNIMPRESSIVE MID LEVEL LAPSE RATES UNDER 6
DEG C/KM...BUT GIVEN BULK SHEAR VALUES OF 35 TO 40 KNOTS AND THE
UNCERTAINTY AS TO HOW MUCH SUNSHINE PARTS OF THE REGION RECEIVE...
WE WILL CONTINUE TO HIGHLIGHT THE CHANCE FOR GUSTY CONVECTIVE
WINDS.
CONSIDERING ALL OF THE ABOVE...WEDNESDAY SHOULD START OFF DRY
ACROSS OUR FORECAST AREA...BUT AS THE FRONT NEARS DURING THE
MIDDAY...CONVECTION WILL BEGIN TO BREAK OUT. THIS MAY BE HASTENED
ACROSS PARTS OF THE SRN TIER AND FINGER LAKES REGION WHERE A LAKE
BREEZE BOUNDARY COULD FOCUS AN INITIAL ROUND OF STORMS...THEN AS
THE FRONT SLOWLY CROSSES THE LOWER GREAT LAKES IN THE AFTERNOON
AND EVENING...THE GENERAL CONDITIONS WILL FURTHER DETERIORATE.
WILL MAINTAIN LIKELY POPS REGIONWIDE FOR THE LATE AFTERNOON...
BUT THE VAST MAJORITY OF THE DAY SHOULD BE RAIN FREE. OTHERWISE
WEDNESDAY WILL BE WARM AND HUMID WITH MAX TEMPS RANGING FROM THE
LOWER 80S OVER THE FAR WEST TO THE MID AND POSSIBLY UPPER 80S
ACROSS PARTS OF THE FINGER LAKES.
DURING THE COURSE OF WEDNESDAY NIGHT...THE FRONTAL BOUNDARY WILL
LAZILY CROSS OUR FORECAST AREA AS UPSTREAM SFC WAVES WILL RETARD
ITS FORWARD PROGRESS. THIS IS THE TIME PERIOD WHERE THE AXIS OF
THE DEEPEST MOISTURE WILL CROSS OUR FORECAST AREA. WHILE DIURNALLY
ENHANCED INSTABILITY WILL BE WANING...THE PASSAGE OF ANY WAVES
ALONG THE FRONTAL BOUNDARY COULD SYNOPTICALLY ENHANCE ANY SHOWERS
INTO A 2 TO THREE HOUR PERIOD OF STEADIER RAIN. THIS POTENTIAL
WILL BE GREATEST OVER THE SRN TIER AND FINGER LAKES REGION.
AGAIN...WE WILL BE FORTUNATE IN THAT WE HAVE VERY DRY ANTECEDENT
CONDITIONS.
ON THURSDAY...WEAK HIGH PRESSURE OVER LOWER MICHIGAN WILL
GRADUALLY BUILD ACROSS OUR FORECAST AREA WHILE THE FLEXUOUS
FRONTAL BOUNDARY WILL MAKE ITS WAY TO THE EAST COAST. SHOWERS...
THAT WILL BE MOST LIKELY EAST OF LINE FROM ROCHESTER TO
JAMESTOWN...WILL TAPER OFF FROM WEST TO EAST IN THE PROCESS.
SUNSHINE SHOULD RETURN IN FORCE TO THE NIAGARA FRONTIER AND PARTS
OF THE SRN TIER BY THE AFTERNOON...BUT THE IMPROVEMENT WILL TAKE
LONGER FURTHER EAST. IT WILL START TO FEEL MUCH MORE COMFORTABLE
AS WELL...AS THE FRESH AIRMASS WILL START TO SETTLE OVER THE
REGION WITH DEW POINTS OVER THE WESTERN COUNTIES STEADIER FALLING
THROUGH THE 50S. AFTER NEARLY TWO WEEKS OF AFTERNOON TEMPERATURES
IN THE 80S...MAX TEMPS ON THURSDAY SHOULD FINALLY RETURN TO THE
70S.
THE GRADUAL CLEARING PROCESS WILL CONTINUE THURSDAY NIGHT AS THE
LEADING EDGE OF HIGH PRESSURE WILL WORK ACROSS OUR FORECAST AREA.
ANY LEFTOVER SHOWERS OVER EASTERN SECTIONS SHOULD END DURING THE
EVENING WITH MUCH MORE COMFORTABLE SLEEPING CONDITIONS GAINING A
FOOTHOLD OVER THE ENTIRE FORECAST AREA. OVERNIGHT LOWS WILL
GENERALLY BE IN THE 50S...WITH THE RADIATIONAL COOLING PROBABLY
LEADING TO SOME VALLEY FOG ACROSS PARTS OF THE SRN TIER AND FINGER
LAKES REGIONS.
WHILE PLEASANT WEATHER IS EXPECTED ACROSS OUR REGION ON FRIDAY...
A MID LEVEL DISTURBANCE DIGGING INTO THE GREAT LAKES LONGWAVE
TROUGH WILL ENCOURAGE SOME `BAGGINESS` IN THE SFC PRESSURE FIELD
ACROSS THE UPPER OHIO VALLEY. THIS WILL BE THE BEGINNINGS OF WHAT
COULD POTENTIALLY BE A CLOSED LOW FOR OUR REGION DURING THE
UPCOMING WEEKEND. MORE ON THIS LOW CONFIDENCE EVENT IN THE LONG
TERM SECTION BELOW. GENERALLY PARTLY SUNNY SKIES CAN BE EXPECTED
ON FRIDAY WITH AFTERNOON TEMPERATURES IN THE 70S BEING ACCOMPANIED
BY COMFORTABLY LOW HUMIDITY LEVELS.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
ONCE AGAIN...THE MEDIUM RANGE GUIDANCE PACKAGES ARE VASTLY
DIFFERENT IN THEIR SOLUTIONS OVER THE LOWER GREAT LAKES IN THE
DAYS 5-7 PERIOD. BOTH THE GFS AND ECMWF OPERATIONAL MODELS ARE
STUBBORNLY HOLDING ONTO THE SAME SCENARIOS THAT THEY HAVE BEEN
PREACHING FOR THE PAST COUPLE DAYS... WITH THE LATTER DEPICTING
THE DEVELOPMENT OF A STACKED STORM SYSTEM OVER SOUTHERN ONTARIO
AND THE LOWER GREAT LAKES. NEEDLESS TO SAY...THIS WOULD BE A VERY
UNSETTLED SOLUTION FOR OUR FORECAST AREA WITH FAIRLY WIDESPREAD
FREQUENT SHOWERS.
BECAUSE OF THE DISPARITY WITHIN THE GUIDANCE PACKAGES...HAVE NO
CHOICE BUT TO KEEP THE LOW/SLGT CHC BROADBRUSH POPS THAT ARE IN
CONTINUITY IN PLACE THROUGH AT LEAST THE WEEKEND.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
OUTSIDE OF SOME ISOLATED/SCATTERED SHOWERS AND THUNDERSTORMS OVER
THE HIGHER TERRAIN INLAND FROM THE LAKES... MAINLY VFR CONDITIONS
WILL PREVAIL ACROSS THE AREA LATE THIS AFTERNOON THROUGH TONIGHT.
A COLD FRONT WILL APPROACH THE AREA ON WEDNESDAY BRINGING SCATTERED
SHOWERS AND THUNDERSTORMS ACROSS THE NIAGARA FRONTIER AND SAINT
LAWRENCE RIVER VALLEY. CONVECTION WILL BECOME MORE NUMEROUS INLAND
FROM THE LAKES AND TOWARD CENTRAL NEW YORK AS THE FRONT PROGRESSES
EASTWARD TOWARD WEDNESDAY MIDDAY/AFTERNOON. OUTSIDE OF TEMPORARY
VIS/CIG REDUCTIONS IN STORMS... MAINLY VFR CONDITIONS WILL PREVAIL.
OUTLOOK...
THURSDAY...SCATTERED TO NUMEROUS SHOWERS TAPERING OFF WITH CONDITIONS
IMPROVING TO VFR.
FRIDAY...MAINLY VFR...EXCEPT IN POSSIBLE MORNING SOUTHERN TIER
VALLEY FOG.
SATURDAY AND SUNDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
HIGH PRESSURE CENTERED OVER THE MID ATLANTIC COASTLINE WILL SLOWLY
DRIFT OFFSHORE THROUGH MIDWEEK. A STALLED OUT COLD FRONT DRAPED FROM
THE SAINT LAWRENCE VALLEY SOUTHWESTWARD ACROSS LAKE ONTARIO WILL LIFT
BACK NORTH OF THE REGION AS A WARM FRONT THIS AFTERNOON AND EVENING
IN RESPONSE TO DEVELOPING LOW PRESSURE ACROSS THE UPPER GREAT LAKES...
THEN THIS LATTER FEATURE WILL SLOWLY EASE ITS TRAILING COLD FRONT
ACROSS THE AREA WEDNESDAY AFTERNOON AND NIGHT.
THE INITIAL FRONTAL BOUNDARY WILL CONTINUE TO TRIGGER SCATTERED
SHOWERS AND THUNDERSTORMS AS IT LINGERS NEAR THE LOWER GREAT LAKES
THIS MORNING...WITH THESE THEN GRADUALLY DIMINISHING FROM SOUTHWEST
TO NORTHEAST THIS AFTERNOON AND EVENING AS THE BOUNDARY LIFTS AWAY
FROM OUR REGION. FOLLOWING ITS DEPARTURE...GENERALLY DRY CONDITIONS
ARE EXPECTED FOR THE BALANCE OF TONIGHT...BEFORE THE TRAILING COLD
FRONT BRINGS MORE NUMEROUS SHOWERS AND THUNDERSTORMS AS IT PASSES
THROUGH THE REGION WEDNESDAY AFTERNOON AND NIGHT.
WHILE ANY OF THE SHOWERS/STORMS COULD PRODUCE LOCALLY HIGHER WINDS AND
WAVES OVER THE NEXT COUPLE OF DAYS...IN GENERAL LIGHT TO MODEST WINDS
WILL PREVAIL ACROSS THE LOWER LAKES REGION THROUGH WEDNESDAY NIGHT...
ALONG WITH WAVES OF UNDER 3 FEET.
FOLLOWING THE PASSAGE OF THE FRONT...HIGH PRESSURE IS EXPECTED TO
BUILD ACROSS THE REGION THURSDAY AND FRIDAY WHILE BRINGING A RETURN
TO MORE SETTLED CONDITIONS...ALONG WITH CONTINUED LIGHT TO MODEST
WINDS AND MINIMAL WAVES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JJR
NEAR TERM...CHURCH/JJR
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...CHURCH
MARINE...JJR
AREA FORECAST DISCUSSION
NWS AMARILLO TX
242 PM CDT TUE SEP 8 2015
.DISCUSSION...
LATEST SURFACE OBS SHOWS THE COLD FRONT EXTENDING FROM JUST NORTH OF
WHEELER SOUTHWESTWARD TO NEAR CLAUDE. MORNING SOUNDING INDICATES
CONSIDERABLE MOISTENING IN THE MID LEVELS AS EVIDENT BY WIDESPREAD
ALTOSTRATUS OBSERVED ACROSS MOST OF THE AREA. POST FRONTAL AIR MASS
IS RELATIVELY COOL ESPECIALLY WHERE MID CLOUDS ARE MOST EXTENSIVE.
TEMPERATURES AT 19Z RANGE FROM THE MID 70S TO THE MID 80S BEHIND THE
FRONT. DESPITE MOIST ADVECTION BEHIND THE FRONT IN THE
NORTHEAST...DIABATIC HEATING HAS BEEN INSUFFICIENT FOR MEANINGFUL
INSTABILITY TO DEVELOP. TEMPERATURES WERE NEAR 100 DEGREES IN THE
FAR SOUTHEAST WHERE SOUTHWESTERLY SURFACE WINDS PREVAIL AND CLOUD
COVER HAS BEEN LIMITED. THIS IS WHERE INSTABILITY HAS INCREASED THE
MOST AND GIVEN LOW/MID 60 DEGREE DEW POINTS MODERATE INSTABILITY HAS
DEVELOPED DESPITE WEAK MID LEVEL LAPSE RATES. SO FAR CONVECTION HAS
BEEN RELATIVELY BENIGN AND CONFINED MOSTLY TO ALONG AND JUST BEHIND
THE FRONT ACROSS EAST CENTRAL AND NORTHEAST PORTIONS OF THE TEXAS
PANHANDLE. SOME INTENSIFICATION SHOULD OCCUR LATER THIS AFTERNOON BUT
CHANCES WILL DECREASE FAIRLY QUICKLY LATER THIS AFTERNOON AND
ESPECIALLY BY EVENING AS LIFT ASSOCIATED WITH A WEAK SHORTWAVE SHIFTS
EASTWARD INTO OKLAHOMA. THIS SHORTWAVE IS DIFFICULT TO SEE BUT SOME
INDICATION IN WATER VAPOR IMAGERY AND RAP PV ANALYSIS SUPPORTS TRENDS
SEEN ON RADAR.
MODERATE INSTABILITY IN THE SOUTHEAST AND EAST CENTRAL TEXAS
PANHANDLE RAISES SOME CONCERN FOR SEVERE POTENTIAL. A MISALIGNMENT
OF BEST SHEAR BEHIND THE FRONT (WHERE NORTHERLY/NORTHEASTERLY FLOW
EXISTS) FROM THE MOST SIGNIFICANT INSTABILITY SOUTHEAST OF THE FRONT
IS A NEGATIVE FACTOR. WEAKLY ORGANIZED UPDRAFTS IN THE SOUTHEAST PART
OF THE TEXAS PANHANDLE THROUGH THE AFTERNOON INTO THE EARLY EVENING
COULD RESULT IN BRIEF/ISOLATED MARGINALLY SEVERE HAIL OR WIND GUSTS.
LOCALLY HEAVY RAIN WILL BE POSSIBLE GIVEN MODEST STORM MOTIONS AND A
MOIST ENVIRONMENT WITH PWATS AROUND AN INCH AND A HALF.
HAVE SCALED BACK PRECIPITATION PROBABILITIES LATER TONIGHT BASED ON
TRENDS AND AM QUITE CONFIDENT IN A DRY FORECAST FOR TOMORROW. POST
FRONTAL ENVIRONMENT WILL BE COOLER BUT ONLY SLIGHTLY BELOW NORMAL
VALUES FOR EARLY TO MID SEPTEMBER. DURING THE MID WEEK PERIOD BROAD
CYCLONIC FAIRLY SWIFT MID/UPPER FLOW WILL COVER MUCH OF THE NORTHERN
PORTIONS OF THE COUNTRY. OVERALL NOT MUCH CHANGE WAS MADE TO THE
PREVIOUS FORECAST. THE CHALLENGE WILL SHIFT TOWARD RESOLVING FAST
MOVING SHORTWAVE TROUGHS EMBEDDED WITHIN THE LARGER UPPER LOW OVER
EASTERN CANADA THROUGH THE END OF THE WEEK. MODELS BRING THE FIRST
WAVE THROUGH THE CENTRAL PLAINS LATE THURSDAY THROUGH EARLY FRIDAY
FORCING ANOTHER COLD FRONT THROUGH. CONTINUED THE TREND OF
DOWNPLAYING DAYTIME PRECIPITATION CHANCES ACROSS MUCH OF THE REGION
EXPECT THE NORTHERN TEXAS PANHANDLE AND OKLAHOMA PANHANDLE. CHANCES
SPREAD SOUTH THROUGH THE NIGHT. GIVEN BETTER MODEL AGREEMENT WE NOW
HAVE HIGHER CONFIDENCE ON COOLER WEATHER ON FRIDAY BEHIND THE FRONT
WHICH SHOULD PERSIST INTO SATURDAY. TEMPERATURES RETURN TO NEAR
NORMAL LEVELS SUNDAY INTO THE BEGINNING OF NEXT WEEK AS UPPER FLOW
PATTERN AMPLIFIES FURTHER. THE VERY PRONOUNCED WAVE IN THE GFS MODEL
EMBEDDED WITHIN THE NORTH-NORTHWESTERLY FLOW BETWEEN BUILDING RIDGE
IN THE WEST AND DEEPENING TROUGH IN THE EAST THIS WEEKEND IS FURTHER
EAST AND NOT QUITE AS PRONOUNCED. THIS IS MORE IN LINE WITH OTHER
MEDIUM RANGE GUIDANCE AND WAS ENOUGH FOR US TO KEEP THE LATTER
PORTION OF THE EXTENDED DRY FOR NOW.
BRB
&&
.PRELIMINARY POINT TEMPS/POPS...
AMARILLO TX 62 82 60 87 61 / 20 5 5 20 20
BEAVER OK 63 83 61 91 62 / 10 5 0 20 40
BOISE CITY OK 58 82 59 89 60 / 10 5 5 30 30
BORGER TX 63 85 63 90 64 / 20 5 5 20 40
BOYS RANCH TX 62 84 60 89 60 / 20 5 5 20 20
CANYON TX 63 82 59 88 61 / 20 5 5 20 20
CLARENDON TX 63 82 62 88 64 / 20 10 5 10 20
DALHART TX 58 83 59 89 59 / 10 5 5 30 30
GUYMON OK 63 84 61 90 61 / 10 5 0 30 40
HEREFORD TX 63 81 60 87 60 / 20 5 5 20 20
LIPSCOMB TX 63 83 61 89 61 / 20 0 0 20 40
PAMPA TX 62 82 61 87 60 / 20 5 0 10 40
SHAMROCK TX 65 84 62 89 63 / 40 5 0 5 30
WELLINGTON TX 66 85 62 90 65 / 40 5 0 5 20
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
8/17