Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/05/14
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
856 PM MST THU SEP 4 2014
.SYNOPSIS...
INCREASING SOUTHERLY FLOW ALOFT WILL CONTINUE TO GRADUALLY INCREASE
MOISTURE LEVELS OVER THE DESERT SOUTHWEST THROUGH FRIDAY...WITH
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS OVER THE REGION. A
FURTHER INCREASE IN MOISTURE IS EXPECTED THIS WEEKEND AS MOISTURE
FROM THE REMAINS OF HURRICANE NORBERT SURGES INLAND INTO THE
REGION...WITH HEAVY RAIN AND LOCALIZED FLOODING POSSIBLE. A SLOW
DRYING TREND IS THEN EXPECTED TO BEGIN NEXT WEEK AS HIGH PRESSURE
SLOWLY REBUILDS OVER THE REGION.
&&
.DISCUSSION...
WHAT TURNED OUT TO BE A SLOW START EARLY THIS AFTERNOON WITH MOST
STORM ACTIVITY TO THE SOUTH OF OUR AREA ACTUALLY ENDED UP BEING
QUITE ACTIVE AFTER A SERIES OF OUTFLOWS REPEATEDLY SPAWNED SHOWERS
AND THUNDERSTORMS ALONG THE LEADING EDGES. THOUGH STORM COVERAGE WAS
QUITE EXTENSIVE...THE ATMOSPHERE STILL REMAINS SOMEWHAT ON THE DRY
SIDE...SO RAINFALL AMOUNTS WERE FAIRLY LIMITED. A FEW LOCATIONS
SOUTH OF GILA BEND AND WEST OF PHOENIX LIKELY SAW CLOSE TO AN INCH
OF RAINFALL...BUT THE VAST MAJORITY OF THE AREA SAW ONLY A TRACE TO
A TENTH OF AN INCH. THE 00Z RAOBS FOR BOTH PHOENIX AND TUCSON SHOWED
NO INCREASE INCREASE IN PRECIPITABLE WATER VALUES...BUT FAIRLY STEEP
MID-LEVEL LAPSE RATES WERE OBSERVED. A SUBTLE SHORTWAVE TROUGH WAS
OBSERVED IN THE WIND FIELD THIS AFTERNOON AND EVENING MOVING ACROSS
SOUTHWEST ARIZONA INTO SOUTH-CENTRAL ARIZONA. THIS SHORTWAVE LIKELY
AIDED IN STORM DEVELOPMENT ALONG WITH THE NUMEROUS OUTFLOWS CREATING
LOW LEVEL CONVERGENT AREAS.
STORM ACTIVITY CONTINUES AS OF 9 PM FROM NORTHERN MARICOPA COUNTY
EASTWARD THROUGH GILA AND PINAL COUNTIES. EXPECTING THIS ACTIVITY TO
GRADUALLY WIND DOWN BY MIDNIGHT WITH SOME SHOWERS LIKELY LINGERING
ACROSS SOUTHEAST AND EAST-CENTRAL ARIZONA DURING THE OVERNIGHT HOURS.
MADE SOME ADJUSTMENTS TO POPS DURING THE OVERNIGHT ADDING IN SLIGHT
CHANCES THROUGH THE PHOENIX AREA AND INCREASING POPS SLIGHTLY TO
AROUND 20 PERCENT TO THE EAST OF PHOENIX. ALSO MADE TWEAKS TO THE
SKY GRIDS GIVEN THE CURRENT EXTENSIVE CLOUDINESS EXPECTING PARTLY TO
MOSTLY CLOUDY SKIES TO LAST THROUGH MUCH OF THE OVERNIGHT ACROSS
SOUTH-CENTRAL ARIZONA.
&&
.PREVIOUS DISCUSSION...
TONIGHT AND FRIDAY...
MODELS CONTINUE TO BE CONSISTENT ON THE FORECAST THROUGH
FRIDAY...WITH A SLOW INCREASE IN THE PWAT VALUES OVER AZ TONIGHT
INTO EARLY FRIDAY...MOST LIKELY INTO THE 1.50-1.60 INCH RANGE. THIS
MODEST MOISTURE...COMBINED WITH A WEAK SHORTWAVE THAT IS NOW SEEN IN
THE LATEST WV SATELLITE IMAGERY MOVING INTO EXTREME SOUTHERN AZ...IS
NOW TRIGGERING ISOLATED TO SCATTERED THUNDERSTORMS OVER PIMA COUNTY.
THE LATEST HRRR HI-RES MODEL RUN IS NOW SHOWING MOST OF THESE STORMS
REMAINING TO THE SOUTH OF OUR CWA...BUT WITH A FEW OF THE STORMS
MOVING INTO OR DEVELOPING OVER SOUTH-CENTRAL AZ. THE MAIN THREAT
FROM THESE STORMS WILL BE GUSTY WINDS AND BLOWING DUST...WITH ONLY A
SLIGHT CHANCE FOR MEASURABLE RAIN AT ANY ONE SPOT.
FRIDAY STILL LOOKS LIKE A BIT OF A DOWN DAY...WITH THE LATEST GFS
PRETTY MUCH MATCHING EARLIER RUNS...WITH WEAK HIGH PRESSURE RIDGING
REBUILDING INTO THE REGION FROM THE WEST AND PWATS FALLING A
BIT...INTO THE 1.40-1.50 INCH RANGE...WHICH SHOULD KEEP TS ACTIVITY
LIMITED TO SOUTH-CENTRAL AZ...MOSTLY OVER THE HIGHER TERRAIN NORTH
AND EAST OF PHOENIX.
SATURDAY THROUGH MONDAY...
THIS PERIOD LOOKS MORE-AND-MORE LIKELY THAT IT WILL BE A QUITE
ACTIVE...AS MOISTURE FROM HURRICANE NORBERT BEGINS TO IMPACT THE
REGION. THE LATEST (21Z) NHC FORECAST CONTINUES TO TRACK THIS STORM
TO THE WEST OF THE BAJA CALIFORNIA PENINSULA OVER THE NEXT 3-5
DAYS...WITH AN UPPER TROF THAT WILL BE MOVING SOUTHWARD ALONG THE
NORTHERN AND CENTRAL CA COAST SHEARING MID AND HIGH-LEVEL MOISTURE
NORTHWESTWARD INTO OUR REGION FROM THIS STORM. LATEST MODEL RUNS
ALSO ARE SHOWING A BROAD AREA OF LOW-LEVEL SOUTHEASTERLY FLOW
PUSHING VERY MOIST AIR NORTHWARD ACROSS THE GULF OF CALIFORNIA INTO
AZ AND SE CA...WITH SFC DEWPOINTS EXCEEDING 70F AT ANY LOWER DESERT
LOCATIONS BY SUNDAY MORNING AND PWATS RISING WELL ABOVE 2
INCHES...WHICH IS AT NEAR-RECORD VALUES FOR EARLY SEPT.
GIVEN THESE VERY HIGH AVAILABLE MOISTURE LEVELS...WIDESPREAD
SHOWER/THUNDERSTORM ACTIVITY NOW APPEARS TO BE VERY LIKELY FROM LATE
SAT INTO MONDAY...WITH HEAVY RAIN AND LOCALIZED FLOODING BEING THE
MAIN THREATS FROM STORM-TOTAL RAINFALL AMOUNTS OF 1-2 INCHES...OR
EVEN MORE AT MANY LOWER DESERT LOCATIONS. THE RAIN AND CLOUDS ARE
ALSO EXPECTED TO COOL TEMPS SUBSTANTIALLY DURING THIS PERIOD...WITH
HIGHS REMAINING IN THE 90S...AND EVEN A FEW 80S ACROSS THE LOWER
DESERTS EACH DAY.
TUESDAY THROUGH THURSDAY...
A SLOW DRYING TREND IS EXPECTED THROUGH THIS PERIOD AS INCREASING
WESTERLY FLOW AND BUILDING HIGH PRESSURE OVER THE REGION HELPS TO
SWEEP ANY REMAINING MOISTURE FROM NORBERT WELL OFF TO OUR
EAST...WITH THE THREAT OF THUNDERSTORM ACTIVITY LIKELY ENDING OVER
OUR CWA BY WEDNESDAY OR THURSDAY...WITH DAYTIME HIGHS REBOUNDING TO
NEAR...OR SLIGHTLY ABOVE NORMAL VALUES.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
ISOLATED TO SCATTERED SHOWERS AND A FEW THUNDERSTORMS REMAIN ACROSS
THE METRO AREA AND SHOULD LAST THROUGH AROUND 06Z...THOUGH
DIMINISHING UNTIL THEN. ADDITIONAL OUTFLOWS AND SUDDEN WIND SHIFTS
WILL BE POSSIBLE ALSO UNTIL AROUND 06Z. WINDS WILL GRADUALLY MIGRATE
AROUND TO A EAST SOUTHEASTERLY DIRECTION BY AROUND 09Z. BROKEN CIGS
AROUND 10K WILL LAST THROUGH MUCH OF THE OVERNIGHT...GRADUALLY
SCATTERING OUT AFTER 12Z. STORM CHANCES WILL RETURN FOR FRIDAY
AFTERNOON AND EVENING WITH GUSTY OUTFLOW WINDS AGAIN LIKELY AND ONLY
MARGINAL CHANCES FOR ANY RAINFALL IMPACTING AREA TERMINALS.
SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA INCLUDING KIPL AND KBLH...
MOSTLY CLEAR SKIES SHOULD PREVAIL THROUGH FRIDAY MORNING...THOUGH
SOME INCREASE IN A SCT LOWER DECK...AS WELL AS HIGH DECK MAY BE
POSSIBLE. WIND DIRECTION FORECASTS ARE OF LOWER CONFIDENCE AS
OUTFLOW WINDS AND SOUTHERLY SURGES OF MOISTURE MAY BRING STRONGER
GUSTS EVEN DURING OVERNIGHT HOURS. IN GENERAL...A SOUTHERLY OR
SOUTHEASTERLY COMPONENT WILL BE FAVORED.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SUNDAY THROUGH THURSDAY...
MOISTURE WILL ALREADY HAVE ENVELOPED SOUTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA BY SUNDAY...WITH THE POTENTIAL FOR HEAVY RAINFALL OVER
MUCH OF THE REGION. STORM CHANCES WILL CONTINUE THROUGH TUESDAY
BEFORE TRENDING DOWNWARD THROUGH MIDWEEK. HUMIDITIES WILL REMAIN
VERY ELEVATED DURING THE ENTIRE PERIOD...ONLY FALLING INTO A 30-40
PERCENT RANGE IN THE AFTERNOON WITH MOSTLY COOLER THAN AVERAGE
TEMPERATURES. WINDS MAY BE GUSTY IN AND AROUND THUNDERSTORMS...AND
STAY VARIABLE FOR PROLONGED PERIODS OTHERWISE.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...KUHLMAN
PREVIOUS DISCUSSION...PERCHA
AVIATION...KUHLMAN
FIRE WEATHER...MO
AREA FORECAST DISCUSSION
NWS NEW YORK NY
744 PM EDT THU SEP 4 2014
.SYNOPSIS...
HIGH PRESSURE OVER THE AREA THROUGH TONIGHT WILL SHIFT OFFSHORE
FRIDAY INTO FRIDAY NIGHT AS A COLD FRONT APPROACHES FROM THE
WEST. THE COLD FRONT WILL MOVE ACROSS ON SATURDAY...THEN HIGH
PRESSURE WILL BUILD INTO THE NORTHEAST THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
CU WILL CONTINUE TO DISSIPATE THIS EVENING...LEAVING MAINLY CLEAR
SKIES FOR THE REST OF TONIGHT. THE NAM AND RAP CONTINUE TO SHOW
POTENTIAL FOR LOW STRATUS AND/OR FOG DEVELOPMENT TOWARD DAYBREAK
ACROSS EASTERN LONG ISLAND AND SE CONN. THIS LOOKS QUITE POSSIBLE
BASED ON DEWPOINTS CURRENTLY RUNNING AROUND 70 IN THOSE AREAS AND
POOLING OF LOW LEVEL MOISTURE IN ONSHORE FLOW AND BENEATH A SFC-
BASED INVERSION. HAVE INCREASED CLOUD COVER A BIT AN PUT IN
PATCHY FOG TO COVER THIS POTENTIAL.
EXPECT LOWS IN THE UPPER 50S IN THE LONG ISLAND PINE BARRENS AND
SOME INTERIOR VALLEYS...60S MOST ELSEWHERE...AND LOWER 70S IN NYC.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
EXPECT MAINLY DRY WX AS THE HIGH SHIFTS OFFSHORE. PRESENCE OF A
WEAK SFC TROUGH IN THE WAKE OF THE DEPARTING HIGH...WEAK LOW LEVEL
WAA...AND APPROACH OF MID LEVEL SHORTWAVES FROM THE WEST AND
SOUTHWEST MAY SPARK ISOLD SHOWERS LATE FRI NIGHT. WITH CONTINUED
ONSHORE FLOW THERE SHOULD BE A BETTER CHANCE FOR LOW CLOUDS AND
FOG TO DEVELOP LATE AT NIGHT.
TEMPS ON FRI WITH ONSHORE FLOW AND MORE IN THE WAY OF CLOUDS
SHOULD BE CLOSE TO OR ONLY SLIGHTLY LOWER THAN THOSE OF
TODAY...WITH UPPER 70S FOR COASTAL SE CT AND 80S ELSEWHERE.
LOWS FRI NIGHT SHOULD BE IN THE MID/UPPER 60S INLAND...AND LOWER
70S IN NYC METRO AND LONG ISLAND.
THERE IS A LOW RISK OF RIP CURRENTS AT THE OCEAN BEACHES FOR
MOST OF FRIDAY...BUT IT MAY BECOME BRIEFLY MODERATE LATE IN THE
DAY AND EVENING WITH SEABREEZE DEVELOPMENT.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
DEEP SW FLOW WILL USHER A HOT AND HUMID AIR MASS AHEAD OF A COLD
FRONT ACROSS THE REGION ON SATURDAY WITH SFC DEW POINTS CLIMBING TO
NEAR 70 AND HIGH TEMPS IN THE UPPER 80S TO AROUND 90. THIS WILL
RESULT IN A HEAT INDEX IN THE LOWER TO MID 90S. IN ADDITION...PW
WILL APPROACH 2 INCHES. AS A RESULT...AS COLD FRONT APPROACHES
FROM THE WEST...THERE WILL BE SUFFICIENT ENERGY AND MOISTURE FOR
SHOWERS AND THUNDERSTORMS...WITH ACTIVITY INCREASING THROUGH THE
AFTERNOON. HEAVY RAIN...GUSTY WINDS...AND HAIL WILL BE POSSIBLE
WITH THE STRONGER STORMS. WILL KEEP POPS CAPPED AT LIKELY FOR
NOW...IN LINE WITH THE LATEST MODEL GUIDANCE.
COLD FRONT PUSHES THROUGH THE REGION FROM WEST TO EAST SATURDAY
NIGHT...AND SHOWERS/THUNDERSTORMS WILL TAPER OFF TOWARDS DAYBREAK
SUNDAY. A MUCH DRYER AIR MASS BUILDS INTO THE REGION WITH SFC
DEWPOINTS DROPPING INTO THE 50S BY SUNDAY AFTERNOON...AND HIGHS WILL
FALL TO LEVELS A FEW DEGREES BELOW NORMAL...IN THE MID TO UPPER 70S.
HIGH PRES BUILDS INTO THE REGION MONDAY AND TUESDAY WITH DRY
CONDS...AND THEN MOVES OFFSHORE TUESDAY NIGHT. AS LOW PRES OVER THE
MIDWEST APPROACHES...A WARM FRONT WILL LIFT NORTH INTO THE REGION ON
WEDNESDAY. UNSETTLED WEATHER POSSIBLE FOR WEDNESDAY AND THURSDAY OF
NEXT WEEK. TEMPS WILL AVERAGE TO NEAR NORMAL LEVELS DURING THIS
TIME....GENERALLY IN THE 70S.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
HIGH PRES REMAINS E OF THE REGION THRU FRI.
MAINLY VFR THRU THE TAF PERIOD. THERE IS A CHC FOR MVFR VSBY AT
THE OUTLYING TERMINALS AFT 4-6Z TIL 13Z. IN THE EXTENDED
TAFS...MVFR VSBY MAY AGAIN DEVELOP FRI NGT.
THERE IS A CHC FOR ISOLD TSTM DEVELOPMENT W OF THE CITY FRI AFTN
AND EVE. ACTIVITY EXPECTED TO REMAIN W OF THE TAF SITES ATTM.
LGT AND VRB WINDS TNGT...WITH ANY PREVAILING DIRECTION AROUND 180
TRUE. S WINDS TO AROUND 10KT FRI...STRONGER AT THE COASTS.
IN THE EXTENDED TAFS...FLOW VEERS SLIGHTLY TO AROUND 200 TRUE FRI
EVE.
...NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.
KLGA FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.
KEWR FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.
KTEB FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.
KHPN FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.
.OUTLOOK FOR 00Z SATURDAY THROUGH TUESDAY...
.FRIDAY NIGHT...MVFR OR LOWER POSSIBLE IN ANY LOW CLOUDS AND/OR
FOG. SLIGHT CHANCE SHRA/TSTM W OF CITY TERMINALS.
.SATURDAY TO SATURDAY NIGHT...MVFR OR LOWER POSSIBLE IN SCT-
NUMEROUS SHRA/TSTMS. LOW CLOUDS AND/OR FOG POSSIBLE EARLY IN THE
MORNING. SW-W WINDS G20+ KT POSSIBLE SATURDAY...SHIFTING TO THE
NW-N SATURDAY NIGHT.
.SUNDAY-MONDAY...VFR. E WINDS G20KT POSSIBLE IN THE AFTERNOON ON
MONDAY.
.TUE...VFR.
&&
.MARINE...
DEPARTING HIGH PRESSURE WILL KEEP SUB-SCA CONDITIONS IN PLACE
THROUGH FRI NIGHT.
OCNL GUSTS TO 25 KT ARE POSSIBLE ON SAT AS THE PRES GRADIENT
TIGHTENS WITH THE APPROACH AND PASSAGE OF A COLD FRONT. HIGH PRES
THEN BUILDS OVER THE WATERS FOR THE START OF THE NEW WEEK.
A PERSISTENT EASTERLY FLOW WILL DEVELOP ON THE WATERS...POSSIBLY
PUSHING OCEAN SEAS CLOSE TO SCA LEVELS BY THE MIDDLE OF THE NEW
WORK WEEK.
&&
.HYDROLOGY...
SHOWERS AND THUNDERSTORMS ARE LIKELY SAT INTO SAT NIGHT.
STRONGER STORMS COULD PRODUCE HEAVY RAIN AND LOCALIZED FLOODING
OF URBAN/POOR DRAINAGE AREAS AND SMALL STREAMS.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GOODMAN/MPS
NEAR TERM...GOODMAN/MPS
SHORT TERM...GOODMAN
LONG TERM...MPS
AVIATION...JMC
MARINE...GOODMAN/MPS
HYDROLOGY...MPS
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
350 PM EDT WED SEP 3 2014
.DISCUSSION...
CURRENT/TONIGHT...
LATEST RUC SHOWS THE AXIS OF THE ERLY WAVE HAS MOVED LITTLE SINCE
DAYBREAK WITH THE H85-H50 AXIS AS WELL AS ITS H100-H70 REFLECTION
STILL LURKING JUST OFF THE E FL COAST AS OF MID AFTN. RADAR SHOWING
SCT SHRAS OVER THE INTERIOR THAT WILL PUSH W OF THE CWA WELL BEFORE
SUNSET. UPSTREAM...A SECOND BAND OF SHRAS/TSTMS OVER THE ATLC WILL
PROVIDE NEXT ROUND OF PRECIP FOR EAST CENT FL.
WHILE MID LVL ENERGY IS PRESENT IN THE FORM OF A BAND OF DEEP LYR
VORT BTWN THE NRN BAHAMAS AND THE E FL COAST...THE BULK OF THE
ENERGY REMAINS WELL S AND E OF LAKE OKEECHOBEE. RUC ANALYSIS
INDICATES MID LVL LAPSE RATES HAVE CHANGED LITTLE SINCE THE MRNG
RAOBS WITH H85-H50 READINGS HOLDING ARND 5.5C-KM. UPSTREAM MOISTURE
REMAINS PLENTIFUL WITH H100-H70 MEAN RH VALUES AOA 80PCT...H85-H50
VALUES AOA 60PC...BUT A REFLECTION OF THE DRY TONGUE LINGERS OVER
THE SPACE COAST WITH H85-H50 RH DECREASING TO AOB 40PCT.
CHC SHRAS ALONG THE COAST OVERNIGHT AND OKEECHOBEE COUNTY
OVERNIGHT...INCREASING N TO S TO REFLECT THE CURRENT MOISTURE
PROFILE. WILL KEEP SLGT CHC SHRAS IN FOR THE INTERIOR N OF
OKEECHOBEE COUNTY THRU 02Z TO ACCOUNT FOR ONGOING PRECIP...BUT GIVEN
THE LACK OF EITHER DYNAMIC OR THERMODYNAMIC INSTABILITY...THESE
SHOULD COLLAPSE ONCE THE LOSS OF DIURNAL HEATING KICKS IN. MIN TEMPS
IN THE L/M70S.
THU-FRI...
THE ERLY WAVE WILL ROTATE AROUND THE WRN FLANK OF THE ATLC RIDGE AND
ALLOW DEEP MOISTURE TO INCREASE ACRS CENTRAL FL WITH PWATS
RECOVERING TO ARND 1.8" ON THU...AND BTWN 2.0"-2.2" ON FRI. WITH THE
CWA GAINING THE ASCENDING SIDE OF THE WAVE...NUMEROUS SHRA AND SCT
TSRAS SHOULD FORM EACH DAY. LCL HEAVY RAIN MAY OCCUR WITH STRONGER
THAT DVLP IN THE AFTERNOON AS H50 TEMPS COOL TO ARND -8C. PRECIP
CHANCES SLIGHTLY LOW ON FRI AS THE WAVE BEGINS TO PUSH INTO THE
GOMEX WITH THE ATLC RIDGE REBUILDING IN ITS WAKE.
DESPITE INCREASING CLOUD COVER...SE LOW LVL WINDS WILL GENERATE AFTN
MAX TEMPS TO PUSH MAX TEMPS INTO THE U80S/L90S AREAWIDE. ONSHORE
FLOW AND SFC DEWPOINTS IN THE L/M70S WILL KEEP MIN TEMPS A FEW DEGS
ABV AVG...GENERALLY IN THE M/U70S.
EXTENDED...(PREV DISC)
SAT-SUN...THE ATLANTIC RIDGE WILL EXTEND WEST ACROSS CENTRAL FL OVER
THE WEEKEND WITH A RETURN A MORE TYPICAL SEA BREEZE REGIME WITH LESS
INFLUENCE FROM UPPER LEVEL FEATURES AS THE MID LVL RIDGE REBUILDS
OVER THE STATE. THE EAST COAST SEA BREEZE SHOULD MOVE INLAND EACH
AFTERNOON WITH THE HIGHEST SHOWER/THUNDERSTORM COVERAGE WEST OF I-95
INTO THE INTERIOR BY THE MID TO LATE AFTERNOON HOURS. RAIN CHANCES
AROUND 30 CLOSE TO THE COAST AND 40-50 PERCENT FOR THE INTERIOR.
HIGHS AROUND 90 COAST TO AROUND 93 FOR THE INTERIOR ZONES.
MON-WED...APPEARS THE MID LVL RIDGE WILL REMAIN IN CONTROL EARLY
NEXT WEEK WITH LOW LVL SE WINDS FORECAST. THIS SHOULD AGAIN FAVOR
THE INTERIOR FOR AFTERNOON STORMS WITH THE INLAND MOVING DIFFUSE
EAST COAST BREEZE. MOISTURE LEVELS LOOK TO DIMINISH SOME SO WILL
FORECAST RAIN CHANCES 30 PCT COASTAL TO 40 PCT FOR THE INTERIOR. NOT
MUCH DAY TO DAY CHANGE IN HIGH TEMPS EXPECTED WITH AROUND 90 COAST
TO THE LOWER 90S INLAND.
&&
.AVIATION...
THRU 04/00Z...E/SE SFC WND 8-12KTS...SW OF KDED-KVRB SCT MVFR
SHRAS/ISOLD IFR TSRAS WITH PSBL SFC WND G25-30KTS...NE OF KDED-KVRB
ISOLD MVFR SHRAS. BTWN 04/00-04/12Z...SE SFC WNDS AOB 5KTS...CHC
MVFR SHRAS E OF KOMN-KOBE. AFT 04/12Z...E/SE SFC WNDS 5-10KTS...
PREVAILING CIGS BTWN FL100-120...CHC MVFR SHRAS ALL SITES.
&&
.MARINE...
TONIGHT...LIGHT TO GENTLE ERLY BREEZE BCMG SE AS THE AXIS OF AN ERLY
WAVE PUSHES ACRS THE LCL ATLC...SEAS AOB 2FT NEARSHORE AND 2-3FT
OFFSHORE WITH DOMINANT PDS AOA 8SEC. SCT SHRAS AND ISOLD TSRAS...
MORE NUMEROUS GULF STREAM AND NEARSHORE WATERS S OF SEBASTIAN INLET.
THU-FRI...GENTLE TO MODERATE SERLY BREEZE WILL PREVAIL AS THE ERLY
WAVE ROTATES AROUND THE WRN FLANK OF THE ATLC RIDGE. SEAS AOB 2FT
NEARSHORE AND 2-3FT OFFSHORE...DOMINANT PDS ARND 8SEC THU...
DECREASING TO 7SEC N OF ST. LUCIE INLET AND 4-5SEC S OF THE INLET AS
THE SE BREEZE PLACES THE LCL ATLC UNDER THE SHADOW OF GRAND BAHAMA
ISLAND. NMRS SHRAS AND SCT TSTMS THU...BCMG SCT/ISOLD ON FRI AS THE
WAVE LIFTS INTO THE GOMEX.
SAT-SUN...
SFC/BNDRY LYR WINDS WILL SHIFT MORE TO THE S ARND 10KTS AS THE ATLC
RIDGE REBUILDS OVER THE FL STRAITS IN THE WAKE OF THE DEPARTING
WAVE. SEAS 2-3FT AREAWIDE. SHRA/TSTM CHANCES DECREASING AS SLIGHTLY
DRIER AND MORE STABLE AIR PUSHES INTO THE LCL ATLC.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 74 89 75 88 / 30 50 30 40
MCO 74 93 75 92 / 20 50 20 40
MLB 75 90 77 89 / 40 60 30 40
VRB 72 90 76 89 / 50 60 30 30
LEE 74 93 76 91 / 20 50 20 40
SFB 75 93 76 92 / 20 50 20 40
ORL 75 93 76 92 / 20 50 20 40
FPR 74 89 75 88 / 50 60 30 30
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
FORECAST/AVIATION...BRAGAW
RADAR/IMPACT WX.....CRISTALDI
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
955 AM EDT WED SEP 3 2014
.DISCUSSION...
LATEST RUC ANALYSIS SHOWING AN H100-H70 HI PRES RIDGE EXTENDING FM
THE NRN GULF COAST INTO THE W ATLC...BISECTED BY AN ERLY WAVE BTWN
FL AND THE BAHAMA BANK. WV SAT IMAGERY CONTINUES TO SHOW A BAND OF
DRY MID LYR AIR DRAPED OVER THE S HALF OF FL...THOUGH DEEPER
MOISTURE ASSOCD WITH THE WAVE WAS IMPINGING ON THE SE FL COAST.
MORNING RAOBS CONFIRM THIS WITH PWAT READINGS ARND 1.6" AT
KXMR/KTBW...INCREASING TO 1.9" AT KMFL. MID LVL THERMODYNAMIC
PROFILE HAS BECOME A SLIGHTLY MORE UNSTABLE OVER THE PAST 24HRS WITH
H70 TEMPS ARND 8C...H50 TEMPS ARND -7C...THOUGH LAPSE RATES THRU THE
LYR ARE LANGUISHING BTWN 5.5-6.0C/KM.
ONE NOTEWORTHY TREND ON THE KXMR SOUNDING IS AN INCREASE IN H100-H70
MOISTURE. TREND WILL CONTINUE THRU THE DAY AS RUC ANALYSIS SHOWS
MEAN RH VALUES THRU THE LYR INCREASING UPSTREAM TO ARND 85PCT.
ALTHOUGH THE ASCENDING BACKSIDE OF THE APPROACHING ERLY WAVE REMAINS
BACK OVER THE BAHAMA BANK/FL STRAITS...WITH SFC DEWPOINTS HOLDING IN
THE L/M70S...SHOULD SEE HIGHER PRECIP COVERAGE ACRS E CENT FL THAN
IN RECENT DAYS.
LCL PRECIP MODELS FOCUSING MOST ACTIVITY OVER THE INTERIOR AND ALONG
THE TREASURE COAST...BY AND LARGE BYPASSING THE SPACE COAST. FCST IS
REASONABLE AS STEERING LVL WINDS WILL SHIFT TO THE SE AS THE WAVE
PUSHES ACRS THE REGION THRU LATE AFTN. MINOR ADJUSTMENTS TO PRECIP
TIMING AND COVERAGE...BUT OVERALL TREND WILL REMAIN. COASTAL SHRAS
THRU ERLY AFTN WITH PRECIP SHIFTING INLAND ON THE SEABREEZE. SCT
TSTMS DVLPG INTERIOR THRU LATE AFTN...LINGERING DRY AIR ALOFT WILL
ADD TO DOWNBURST POTENTIAL.
&&
.AVIATION...
THRU 03/16Z...E/SE SFC WNDS AOB 8KTS...BRIEF ISOLD MVFR COASTAL
SHRAS BTWN KTIX-KSUA. BTWN 03/16Z-03/24Z...E/SE SFC WND 8-12KTS...SW
OF KVRB-KDED SCT MVFR SHRAS/ISOLD IFR TSRAS WITH PSBL SFC WND
G25-30KTS...E OF KVRB-KDED ISOLD MVFR SHRAS. AFT 04/00Z...SE SFC
WNDS AOB 5KTS...SCT MVFR SHRAS/ISOLD IFR TSRAS CSTL SITES.
&&
.MARINE...
ERLY WAVE AXIS BTWN THE FL PENINSULA AND THE BAHAMA BANK WILL DRIFT
WEST AND PRODUCE A GENTLE TO MODERATE E/SE BREEZE ACRS THE LCL
ATLC...SEAS SEAS 2-3FT WITH DOMINANT PDS AOA 8SEC. SHRA/TSTM
ACTIVITY WILL INCREASE THRU LATE AFTN AS THE E FL PENINSULA GAINS
THE WAVE`S ASCENDING REAR FLANK.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
FORECAST/AVIATION...BRAGAW
RADAR/IMPACT WX.....CRISTALDI
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
425 AM EDT WED SEP 3 2014
...SCATTERED TO NUMEROUS THUNDERSTORMS TODAY...
.CURRENTLY...
DEEP LAYER RIDGING HAS SHIFTED A BIT FURTHER W SINCE TUE AFTN
AS A MID TO UPPER LEVEL LOW OVER THE SW BAHAMAS IMPINGES ON THE
REGION. AN ATLC SFC RIDGE EXTENDS INTO NRN FL AND CENTRAL GULF COAST.
DEEP LAYER MOISTURE REMAINS IN PLACE WITH PWATS NEAR 2 INCHES PER
00Z RAOB WITH GPS MET DATA SHOWING SLIGHTLY LOWER VALUES. SFC TEMPS
ARE COOLER THAN 24 HRS AGO AND WITH RECENT RAINFALL OVER INLAND
AREAS THERE IS A GOOD CHANCE OF SOME PATCHY FOG DEVELOPING THROUGH
EARLY MORNING. SOME DEBRIS CLOUDS AOA 20 KFT EXPECTED TO SLOWLY
DISSIPATE FROM TUE EVENINGS CONVECTION. LATEST RADAR SHOWS A FEW
SHOWERS OFFSHORE FROM 20NM AND BEYOND LIFTING NWD.
TODAY...A RELATIVELY SIMILAR ENVIRONMENT TO YESTERDAY WITH ELEVATED
MOISTURE LEVELS AND A LIGHT WIND FLOW REGIME ENABLING SEA BREEZES
TO BECOME ACTIVE ONCE AGAIN. A FEW SHOWERS AND STORMS OVER THE
COASTAL WATERS WILL SLOWLY DIMINISH DURING THE DAY DUE TO THE
DEVELOPMENT OF THE E COAST SEA BREEZE. DEEP LAYER FLOW WILL BE WEAK
GENERALLY LESS THAN 5 KNOTS...WITH RIDGING HOLDS WHILE MID TO UPPER
LOW AND TROUGH OVER CUBA AND SRN FL SLOWLY TREKS WWD. MEAN LAYER
WINDS BEGIN TO BECOME ELY BY EARLY EVENING HOURS. THE HRRR MODEL AND
GFS SUGGEST ANOTHER EARLY START TO DEVELOPMENT OF SHOWERS AND
STORMS...MAINLY ALONG AND NEAR THE E COAST SEA BREEZE AROUND
15Z-17Z...AND THEN FAIRLY STEADY INCREASE IN COVERAGE THROUGH THE
AFTN OVER INLAND AREAS. HAVE INCREASED POPS AREA-WIDE TO AROUND
40-60% RANGE WITH SOME HIGH END LIKELY POPS POSSIBLE NEAR THE I-75
CORRIDOR BY LATE AFTN DUE TO INTERACTIONS OF W COAST SEA
BREEZE...OUTFLOWS AND E COAST SEA BREEZE. SIMILAR THREATS
FROM STORMS FROM YESTERDAY...FREQUENT/EXCESSIVE LIGHTNING...LOCALLY
HEAVY RAIN...AND GUSTY WINDS. HIGHS ARE NUDGE DOWNWARD DUE TO
SLIGHTLY LOWER 850 MB TEMPS AND INCREASED DEEP CONVECTIVE
ACTIVITY...WITH LOWER 90S INLAND AND 88-90 AT THE COAST.
TONIGHT...ISOLD TO SCT CONVECTION EXPECTED IN THE EVENING HOURS
BEFORE FADING AFTER MIDNIGHT. THE GFS SHOWS A DRY SLOT NW OF THE
TROUGH TO OUR S SLIDING UP THROUGH OUR FORECAST AREA BY 12Z THU.
THIS WILL ENABLE SOME CLEARING SKIES AND DRY CONDITIONS FILTERING
INTO THE AREA. DESPITE THIS...ARW AND NMM MODELS AS WELL AS THE EURO
MODEL INDICATE ISOLD TO SCT SHOWERS AND STORMS POSSIBLE OVER THE
COASTAL WATERS FROM LOW LEVEL MOISTURE CONVERGENCE. SOME OF THIS
ACTIVITY MAY DRIFT INTO THE BEACHES AND INTRACOASTAL WATERWAY NEAR
OR BEFORE SUNRISE. PATCHY FOG POSSIBLE WELL INLAND AND LOWS MAINLY
LOWER TO MID 70S.
THURSDAY...MUCH DRIER CONDITIONS IN THE MID AND UPPER LEVELS WILL
SHIFT NWWD OVER THE CWA AND HELP LIMIT CONVECTIVE COVERAGE TO AROUND
20-40% WITH A SLIGHTLY HIGHER CHANCE OVER S ZONES WHERE THERE WILL
BE LESS SUBSIDENCE AND MORE MOISTURE AVAILABLE. MEAN FLOW MORE ELY
AND INCREASED A FEW KNOTS HELPING TO PUSH THE E COAST SEA BREEZE
INLAND MORE QUICKLY THAN TODAY. HIGHS CONTINUE IN THE LOWER 90S MOST
LOCATIONS.
THURSDAY NIGHT THROUGH FRIDAY NIGHT...
DEEP MOISTURE WILL INCREASE FROM SOUTH TO NORTH DURING THIS
TIME FRAME AS A WEAKENING TUTT FEATURE MOVES INTO THE
SOUTHEASTERN GULF OF MEXICO...AND A WEAK SURFACE REFLECTION
SLIDES NORTHWARD UP THE FL PENINSULA. INCREASED NOCTURNAL POPS
TO HIGH-END CHANCE OVER THE COASTAL WATERS THURS NIGHT...AND
ADDED CHANCE POPS IN THE COASTAL COUNTIES AND NORTH CENTRAL
FL ON FRI MORNING AS ENHANCED MOISTURE ADVECTS INTO THESE AREAS.
LOWS WILL GENERALLY FALL INTO THE LOWER 70S INLAND...WITH UPPER
70S AT THE COAST. EXPECTING NUMEROUS COVERAGE ALONG THE I-75
CORRIDOR DURING THE AFTERNOON HOURS...WITH DECREASING POPS
TOWARDS THE EARLY EVENING HOURS IN THE COASTAL COUNTIES AS THE
ATLANTIC SEA BREEZE PUSHES WELL INLAND. INCREASING POPS AND CLOUD
COVER SHOULD HOLD HIGHS IN THE UPPER 80S ACROSS MOST OF NORTH
CENTRAL AND NE FL...AND NEAR 90 IN SE GA. SOUTHERLY FLOW BEHIND
THE WEAK SURFACE WAVE WILL LIKELY PUSH ACTIVITY INTO INTERIOR SE
GA DURING THE EVENING HOURS...WHERE ACTIVITY MAY LINGER THROUGH
AROUND MIDNIGHT. OTHERWISE...EXPECTING CONVECTION TO AGAIN BLOSSOM
OVER THE COASTAL WATERS DURING THE OVERNIGHT HOURS DUE TO
DEEPENING SOUTHERLY FLOW. INCREASED MOISTURE AND CLOUD COVER WILL
KEEP LOWS IN THE MID 70S INLAND...AND NEAR 80 AT THE COAST.
.LONG TERM (SATURDAY THROUGH WEDNESDAY)...
FLOW ALOFT WILL TRANSITION TO SOUTHWESTERLY THIS WEEKEND REGION-WIDE
AS WEAK TROUGHING ATTEMPTS TO PUSH INTO THE SOUTHEASTERN STATES...WHICH
WILL SUPPRESS THE AXIS OF ATLANTIC RIDGING TO A POSITION OVER THE FL
PENINSULA. THIS CHANGE IN THE REGIME WILL FOCUS AFTERNOON AND EARLY
EVENING CONVECTION CLOSER TO THE I-95 CORRIDOR...WITH SCATTERED TO
NUMEROUS COVERAGE EXPECTED THIS WEEKEND. OFFSHORE FLOW SHOULD ALLOW FOR
ABOVE NORMAL HIGHS REGION-WIDE...WITH HIGHS CLIMBING INTO THE LOWER 90S
AWAY FROM THE IMMEDIATE COAST...WHERE THE GRADIENT SHOULD REMAIN LOOSE
ENOUGH FOR AN EARLY AFTERNOON SEA BREEZE TO KEEP HIGHS IN THE UPPER 80S.
A RATHER WEAK SURFACE PRESSURE PATTERN WILL PREVAIL FOR THE EARLY AND
MIDDLE PORTIONS OF NEXT WEEK...AND PLENTY OF DEEP-LAYERED MOISTURE WILL
AID IN THE DEVELOPMENT OF AT LEAST SCATTERED DIURNAL CONVECTION...WITH
THE FOCUS SHIFTING BACK TO INLAND LOCATIONS DURING THE AFTERNOON AND
EARLY EVENING HOURS. TEMPERATURES WILL REMAIN ABOVE CLIMO DURING THIS
TIME FRAME.
&&
.AVIATION...PREVAILING VFR TODAY WITH BRIEF PERIOD OF MVFR VSBY
POSSIBLE FOR GNV AND VQQ FROM ABOUT 09Z-11Z. FAVORABLE CONDS FOR
SHOWERS AND STORMS AGAIN TODAY WITH FIRST DEVELOPMENT OF A SHOWER OR
STORM AROUND 16Z-17Z FOR THE COASTAL TAFS. INCLUDED 3 HR TEMPO GROUP
AROUND 17Z-20Z FOR JAX/CRG/VQQ WITH LATER START FOR GNV BY 18Z-19Z.
MVFR CONDS IN STORMS WITH GUSTY WINDS AND SHORT PERIOD OF IFR ALSO
POSSIBLE IN THE STRONGER STORMS. CONVECTION CHANCES DECREASE BY 22Z
OR SO FOR COASTAL TAFS AND AFTER 00Z FOR GNV.
&&
.MARINE...SOUTHEAST TO SOUTH WINDS 10 TO 15 KNOTS WITH SEAS AROUND 2
TO 3 FT. LOCAL SEA BREEZES ALONG THE COAST IN THE AFTERNOONS.
GENERAL FLOW REGIME CHANGE LATE IN THE WEEKEND AS SFC RIDGE
GRADUALLY SHIFTS SWD INTO CENTRAL FL WHILE A WEAK FRONT MOVES INTO
CENTRAL GA...WITH MORE PREVAILING SWLY WINDS SUN.
RIP CURRENTS: MAINLY LOW RISK WITH SMALL SWELLS AROUND 1 TO 1.5 FT
AND SOUTHEAST SEA BREEZES DURING THE DAYTIME HOURS.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 93 72 92 71 / 60 30 30 20
SSI 86 76 86 76 / 40 20 20 20
JAX 90 72 90 73 / 50 20 30 20
SGJ 88 74 87 75 / 40 20 30 20
GNV 90 70 91 71 / 60 30 40 30
OCF 90 71 91 72 / 60 30 50 40
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...NONE.
&&
$$
SHASHY/NELSON
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
625 PM EDT WED SEP 3 2014
.SYNOPSIS...
HIGH PRESSURE WILL PREVAIL INTO THIS WEEKEND. A COLD FRONT WILL
STALL AND DISSIPATE NORTH OF THE REGION BY LATE WEEK...THEN A
STRONGER COLD FRONT COULD ADVANCE INTO THE REGION LATE IN THE
WEEKEND OR EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
WATER VAPOR IMAGERY AND RAP VORTICITY DATA SUGGEST THE AREA IS
UNDER THE INFLUENCE OF BROAD DIFFERENTIAL NEGATIVE VORTICITY
ADVECTION. THIS HAS RESULT IN A GENERAL LACK OF CONVECTIVE
ACTIVITY THIS AFTERNOON...DESPITE ADEQUATE INSTABILITY. THERE IS
STILL A RISK OF AN ISOLATED SHOWER OR TSTMS ACROSS FAR INTERIOR
SOUTHEAST GEORGIA AHEAD OF THE SEA BREEZE...BUT ANY ACTIVITY THAT
FIRES WILL BE SHORT LIVED. ADJUSTED POPS TO 20 PERCENT IN THIS
AREA WITH DRY CONDITIONS ELSEWHERE THROUGH THE EVENING HOURS.
LATER TONIGHT...ISOLATED SHOWERS/TSTMS COULD MOVE ONSHORE IN THE
ONSHORE FLOW/COASTAL CONVERGENCE REGIME. THE LATEST RUNS OF THE
RAP AND H3R SUPPORT THIS SCENARIO. MAINTAINED SLIGHT CHANCE POPS
OVER THE COASTAL WATERS AND BEACHES. LOWS WILL RANGE FROM THE
LOWER-MID 70S INLAND TO THE MID-UPPER 70S AT THE COAST AND
DOWNTOWN CHARLESTON.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
A MODERATELY STRONG...DEEP LAYER RIDGE OF HIGH PRESSURE WILL REMAIN
ANCHORED ACROSS THE ATLANTIC AND SOUTHEAST STATES THROUGH AT LEAST
FRIDAY. BY SATURDAY...THE WESTERN PORTION OF THE RIDGE BEGINS TO
ERODE/BREAK DOWN AS A BROAD UPPER TROUGH BUILDS INTO THE GREAT
LAKES STATES AND NORTHEAST U.S.. THIS UPPER TROUGH WILL ALSO PUSH A
WEAK COLD FRONT TO JUST NORTHWEST OF THE REGION BY LATE SATURDAY.
THURSDAY...MODELS HAVE BEEN CONSISTENTLY SHOWING A NARROW BAND OF
MID AND UPPER LEVEL DRYING TO MOVE INTO THE AREA FOR THE FIRST PART
OF THE DAY AROUND THE NW FRINGE OF THE UPPER/TUTT LOW...CURRENTLY
STRETCHING FROM THE BAHAMAS...SOUTHWEST INTO CUBA. THIS DRIER AIR
WILL HELP TO LIMIT CONVECTIVE COVERAGE. THUS...HAVE KEPT SLIGHT
CHANCE POPS MOST AREAS...EXCEPT LOW END CHANCE EXTREME INTERIOR
WHERE MAX HEATING COMBINES WITH A LATE DAY SEA BREEZE. MAX TEMPS
STILL IN THE LOWER 90S MOST AREAS...AND COMBINED WITH MODERATE LOW
LEVEL HUMIDITY... WILL RESULT IN MAX HEAT INDICES OF 100-103. ANY
CONVECTION SHOULD DIE DOWN AFTER SUNSET...THEN PARTLY CLOUDY WITH
LOWS IN THE 70S.
FRIDAY...BETTER DEEP LAYER MOISTURE ADVANCES BACK IN FROM THE
SOUTHEAST ON THE NW EDGE OF THE UPPER/TUTT LOW WELL TO THE SOUTH IN
THE GULF OF MEXICO. EXPECT SCATTERED MAINLY AFTERNOON AND EARLY
EVENING SHOWERS/THUNDERSTORMS...WITH BEST COVERAGE LIKELY INLAND.
HIGHS AROUND 90 TO THE LOWER 90S. GUIDANCE TRIES TO HOLD ONTO POPS
ALL NIGHT FRIDAY NIGHT...BUT STILL FEEL CONVECTION WILL BE MAINLY
DIURNALLY FORCED. TO LEAN MORE TOWARD GUIDANCE AND TO BETTER
COLLABORATE WITH SURROUNDING OFFICES...HAVE KEPT SLIGHT CHANCE OVER
LAND AND CHANCE OVER WATER/ATLANTIC REGION. LOWS AGAIN IN THE 70S.
SATURDAY...DEEP LAYER MOISTURE REMAINS HIGH WITH PRECIPITABLE WATER
VALUES OVER 2 INCHES. NAM SHOWING A WEAK SURFACE LOW MOVING UP THE
COAST FROM FL TO OFF SC COAST. OTHER MODELS MAINLY SHOW A WEAK
INVERTED SURFACE TROUGH. THE DETAILS OF THE SURFACE FEATURES ARE
STILL UNCERTAIN. HOWEVER...GIVEN SLIGHTLY LOWER UPPER HEIGHTS AND
SUFFICIENT TROPICAL MOISTURE...EXPECT AT LEAST SCATTERED
CONVECTION...AND WOULD NOT BE SURPRISED IF POPS NEED TO BE RAISED
MORE WITH LATER FORECASTS. HIGH TEMPERATURES AROUND 90 TO THE LOWER
90S...BUT MAY BE LOWER IF CONVECTIVE COVERAGE ENDS UP BEING HIGHER
THAN CURRENTLY FORECASTED.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
A SHIFT IN THE PATTERN WILL BRING ABOUT IMPROVING RAIN CHANCES INTO
THE EARLY PART OF NEXT WEEK WITH COOLER TEMPERATURES RESULTING.
HEIGHTS WILL FALL ALOFT AS THE AFOREMENTIONED NORTHERN STREAM TROUGH
MOVES PAST. THIS WILL DRAG A COLD FRONT INTO THE AREA SOMETIME
SUNDAY...LINGERING IN THE VICINITY THROUGH MONDAY BEFORE DISSIPATING
THEREAFTER. PWATS WILL INCREASE TO OVER 2 INCHES AND THE CONVERGENCE
WITHIN THE BOUNDARY IS EXPECTED TO RESULT IN MUCH BETTER COVERAGE OF
SHOWERS AND THUNDERSTORMS SUNDAY...SUNDAY NIGHT...AND INTO MONDAY.
POPS HAVE BEEN INCREASED INTO THE 50 PERCENT RANGE. BY THE LATTER
PORTION OF THE FORECAST...CONFIDENCE IS A BIT LOWER AS THE MODELS
SHOW HIGH PRESSURE TO THE NORTHEAST BUILDING IN WITH THE REMNANT
BOUNDARY SOMEWHERE ALONG THE COAST OR JUST OFFSHORE. IN SHORT...THE
LONG TERM PERIOD FEATURES INCREASING RAIN CHANCES AND COOLER
TEMPERATURES.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
VFR.
EXTENDED AVIATION OUTLOOK...VFR EXPECTED TO PREVAIL THROUGH
FRIDAY. ONLY ISOLATED TO SCATTERED AFTERNOON SHOWERS/THUNDERSTORMS
EXPECTED BOTH TERMINALS WITH BRIEF PERIODS OF FLIGHT RESTRICTIONS
POSSIBLE. RAIN CHANCES MAY INCREASE SATURDAY AND SUNDAY AS EVEN
DEEP TROPICAL MOISTURE TRIES TO MOVE FROM THE SOUTH INTO THE
REGION...AND INTERACTS WITH AN APPROACHING COLD FRONT LATE WEEKEND
AND EARLY NEXT WEEK.
&&
.MARINE...
TONIGHT THROUGH SUNDAY...HIGH PRESSURE WILL CONTINUE TO BE THE PRIMARY
FEATURE THROUGH THE END OF THE PERIOD. A COLD FRONT WILL BEGIN TO
APPROACH THE LOCAL WATERS LATE IN THE WEEKEND...BUT WILL NOT HAVE
A SIGNIFICANT EFFECT ON WINDS/SEAS. THE PREVAILING FLOW WILL
CONTINUE TO BE SOUTH TO SOUTHEASTERLY WITH SPEEDS LESS THAN 15 KT.
PERIODS OF STRONGER FLOW WILL BE POSSIBLE ALONG THE LAND/SEA
INTERFACE WITH THE SEA BREEZE...AS WELL IN MODEST NOCTURNAL
SURGING. SEAS WILL CONTINUE TO BE 1-3 FT...HIGHEST BEYOND 20 NM.
&&
.TIDES/COASTAL FLOODING...
ASTRONOMICAL TIDE HEIGHTS WILL GRADUALLY INCREASE THROUGH THE WEEK
AS WE APPROACH A PERIGEAN FULL MOON NEXT WEEK AND EARLY NEXT WEEK.
EXTRA-TROPICAL STORM SURGE MODEL RUNS HAVE BEEN TRENDING TOWARD
INCREASING TIDE LEVELS THROUGH THE WEEK...WITH THE LATEST RUN NOW
PREDICTING TIDES JUST ABOVE 7 FT MLLW FOR CHARLESTON /MARGINAL
COASTAL FLOODING/...BUT REMAIN JUST BELOW 9 FT FOR FT. PULASKI.
GIVEN THIS LATEST FORECAST...LOOKS LIKE THE BEST THREAT FOR MINOR
COASTAL FLOODING WOULD BE THE CHARLESTON/SC COAST BY SATURDAY. IF
THE ONSHORE FLOW IS STRONGER THAN CURRENTLY PREDICTED...MINOR
COASTAL FLOODING COULD BEGIN AS EARLY AS FRIDAY EVENING.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
ST
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
216 AM EDT WED SEP 3 2014
.PREV DISCUSSION... /ISSUED 1029 PM EDT TUE SEP 2 2014/
.UPDATE...
AFTER AN EARLY START TO CONVECTION OVER THE ATLANTA METRO...FOCUS
QUICKLY SHIFTED TO THE SOUTHEAST ZONES WHERE MIDDLE GEORGIA SAW
NUMEROUS STRONG TO SEVERE THUNDERSTORMS. THIS ACTIVITY HAS SENT AN
OUTFLOW NORTHWARD BACK TO THE METRO BUT NEWLY GENERATED ACTIVITY
HAS BEEN HARD TO COME BY. HRRR DOES INDICATE NW ACTIVITY WILL
SPREAD EASTWARD AND INTERACT WITH AFOREMENTIONED OUTFLOW BUT
REMAINS UNCLEAR IF THIS WILL BE ENOUGH TO GENERATE ADDITIONAL
OVERNIGHT THUNDERSTORM ACTIVITY. FOR NOW...HAVE PLAYED IT AS LOW
END CHANCE POPS IN THE GRIDS FOR MOST LOCATIONS...EXCEPT NORTHWEST
WHERE I HAVE GONE SLIGHTLY HIGHER GIVEN ADDED DYNAMICS IN PLAY.
OTHERWISE FORECAST IS IN GOOD SHAPE AND NO CHANGES ARE PLANNED.
DEESE
&&
PREV DISCUSSION... /ISSUED 817 PM EDT TUE SEP 2 2014/
PREV DISCUSSION... /ISSUED 301 PM EDT TUE SEP 2 2014/
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
WEAK IMPULSE IN THE FLOW PUSHING ACROSS THE EASTERN CONUS TODAY AND
THIS MAY HELP THE SHOWERS AND THUNDERSTORMS ACROSS NORTH GEORGIA
CONTINUE INTO TONIGHT. AFTER THIS THOUGH...NO SIGNIFICANT FEATURE AT
THE UPPER LEVELS TO KEY IN ON IN THE SHORT TERM. BASICALLY WILL
CONTINUE AGAIN TOMORROW WITH THE DIURNALLY DRIVEN THUNDERSTORMS IN
THE AFTERNOON AND EVENING. WITH MUCAPE VALUES OVER 2000 J/KG
WEDNESDAY AFTERNOON...STRONG TO ISOLATED SEVERE STORMS WILL BE
POSSIBLE. THE MAIN THREATS TOMORROW AFTERNOON APPEAR TO BE GUSTY
WINDS AND LOCALLY HEAVY RAINFALL.
FAIRLY BIG DISCREPANCIES IN THE TEMPERATURE GUIDANCE FOR TOMORROW
WITH THE MAV BEING WARMER THAN THE MET. AT ATL...THERE IS A SIX
DEGREE TEMPERATURE DIFFERENCE BETWEEN THESE TWO FOR HIGHS TOMORROW
AFTERNOON. MUCH OF THIS IS CAUSED BY MORE CLOUD COVERAGE DEPICTED BY
THE NAM. THINK THE NAM IS OVERDOING CLOUD COVERAGE THOUGH SO STARTED
WITH A BLEND...AND THEN LEANED TOWARDS THE WARMER SIDE FOR HIGH
TEMPS TOMORROW. ONCE AGAIN BOTH HIGH AND LOW TEMPERATURES WILL BE
ABOVE NORMAL.
11
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
NO CHANGES TO THE CURRENT LONG TERM. SEE PREVIOUS DISCUSSION BELOW...
17
LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
/ISSUED 325 AM EDT TUE SEP 2 2014/
SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS EXPECTED
EACH DAY THROUGH THE LONG TERM.
WEAK TROUGH STILL IN PLACE ACROSS CENTRAL GA WEDNESDAY NIGHT...BUT
WILL EVENTUALLY DISSIPATE ON THURSDAY. ALOFT...A WEAK SHEAR AXIS
WILL REMAIN THROUGH FRIDAY. THE DISSIPATING BOUNDARY AND SHEAR AXIS
ALOFT MAY SERVE TO FOCUS ANY CONVECTION THURSDAY INTO FRIDAY.
A WEAK FRONT IS STILL ON TRACK FOR THE MID TO LATE WEEKEND. WITH
SUCCESSIVE RUNS...THE MODELS HAVE SLOWED THE SOUTHWARD PROGRESS OF
THE BOUNDARY. CURRENTLY...THE FRONT SHOULD MOVE ACROSS NORTHERN GA
LATE SATURDAY/EARLY SUNDAY THEN STALL ACROSS CENTRAL GA BY LATE
SUNDAY/EARLY MONDAY. THE FRONT LOOKS TO BECOME DIFFUSE BY TUESDAY.
TEMPS STILL EXPECTED TO BE ABOVE NORMAL THROUGH THE PERIOD.
NLISTEMAA
&&
.AVIATION...
06Z UPDATE...
MAINLY VFR CONDITIONS THOUGH CHANCE FOR MORNING MVFR VSBYS AT SOME
SITES. CIGS GENERALLY NEAR 12 KFT THIS MORNING WITH SOME SCT NEAR
5 KFT. AFTERNOON CU FIELD LIKELY IN 4-5 KFT RANGE ALONG WITH
DECENT TSRA POTENTIAL AFTER 18-19Z. WINDS GENERALLY LIGHT AND VRB
TO CALM INITIALLY BECOMING NW TO W UNDER 7 KTS TODAY. VRB GUSTS
AND REDUCED VSBYS AGAIN POSSIBLE WITH ANY STORM DEVELOPMENT.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM IN PRECIP TIMING.
HIGH ALL ELSE.
BAKER
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 95 71 92 69 / 40 30 40 30
ATLANTA 90 73 88 70 / 40 40 40 30
BLAIRSVILLE 86 66 84 63 / 40 30 40 30
CARTERSVILLE 91 69 90 68 / 30 30 40 30
COLUMBUS 94 74 90 71 / 40 40 30 20
GAINESVILLE 90 72 89 69 / 40 30 40 30
MACON 94 71 92 69 / 40 40 30 20
ROME 92 69 91 68 / 30 30 40 30
PEACHTREE CITY 90 70 88 68 / 40 40 40 30
VIDALIA 95 73 92 71 / 40 30 30 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...11/DEESE
LONG TERM...NLISTEMAA/17
AVIATION...BAKER
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
135 AM EDT WED SEP 3 2014
.SYNOPSIS...
ISSUED AT 130 AM EDT TUE SEP 2 2014
WITH HIGH PRESSURE OVER THE REGION...SKIES WILL BE MOSTLY CLEAR
AND LOW TEMPERATURES WILL DROP INTO THE 50S OVERNIGHT. THERE WILL
BE AREAS OF FOG WITH PATCHY DENSE FOG IN LOW LYING AREAS AND NEAR
BODIES OF WATER. ONCE THE FOG BURNS OFF ON WEDNESDAY A BEAUTIFUL
EARLY SEPTEMBER DAY WILL BE IN STORE WITH HIGHS IN THE MIDDLE 80S
ALONG WITH LOWER HUMIDITY.
&&
.UPDATE...
ISSUED AT 656 PM EDT TUE SEP 2 2014
FORECAST STILL ON TRACK NEXT COUPLE OF HOURS AS SEVERAL BOUNDARIES
(OUTFLOW AND LAKE BREEZE) WERE DRIFTING SOUTH ACROSS N INDIANA AND
NW OHIO. ISOLATED SHOWERS HAVE POPPED HERE AND THERE AND EVEN A
STRAY LIGHTNING STRIKE A FEW HOURS AGO. TRENDS SHOULD CONTINUE
DOWNWARD WITH LOSS OF HEATING AND EVENTUAL TRANSLATION OF
BOUNDARIES OUT OF THE AREA.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 344 PM EDT TUE SEP 2 2014
INFILTRATION OF DRIER AIR INTO THE REGION HAS BEEN SLOW THIS
AFTERNOON...WITH AMPLE BOUNDARY LAYER MOISTURE AMID WASHED OUT
SURFACE BOUNDARY ACROSS THE FORECAST AREA. LOW CLOUDS HAVE BEEN SLOW
TO MIX OUT THROUGH EARLY AFTERNOON BUT LATEST SAT TRENDS SHOWING
MORE SCT LOW LVL CLOUD LAYER...ESPECIALLY NW. ISOLD SHOWERS
CURRENTLY NOTED ON RADAR ACROSS NW/NC IN...GIVEN AMPLE BOUNDARY
LAYER MOISTURE...WEAK SFC CONVERGENCE AND SFC HEATING YIELDING VERY
MODEST SB CAPES UP TO 1000 J/KG ACROSS THE REGION. HRRR AND EVEN
NAM12 HINTING AT ISOLD SHOWER ACTIVITY SPREADING EAST ACROSS THE
FORECAST AREA THROUGH SUNSET. THEREFORE HAVE KEPT AN ISOLD SHOWER
MENTION THROUGH 00Z IN THE FCST. LOW CONFIDENCE FOR THUNDER AT THIS
TIME GIVEN LACK OF FORCING AND WEAK MID LVL LAPSE RATES.
AS RIDGING BUILDS EASTWARD INTO THE OVERNIGHT HOURS...CLEARING SKIES
AND DRY CONDITIONS EXPECTED. WITH SLACKENING GRADIENT AND LOW LVL
MOISTURE...ESPECIALLY SE W/ THE PRECIP OVER THE PAST 24 HRS...FOG
DEVELOPMENT LOOKS LIKELY LATE IN THE OVERNIGHT INTO DAYBREAK
WEDNESDAY. KEPT PREVIOUS FCST IN TACT WITH AREAS OF FOG MENTION FROM
09-12Z. LOW CONFIDENCE WITH THE POSSIBILITY OF DENSE FOG AT THIS
TIME...GIVEN LOW LEVEL DRY ADVECTION AND EXTENSIVE CIRRUS SHIELD
NOTED ACROSS THE SOUTHWEST HALF OF THE FORECAST AREA THIS AFTERNOON.
IF CLOUD COVER IS QUICK TO DIMINISH TONIGHT...W/ LACK OF ANY
CONVECTIVE DEBRIS...THEN DENSE FOG CHANCES WOULD INCREASE TOWARD
TOMORROW MORNING...ESPECIALLY SE. WILL MONITOR TRENDS THROUGH THE
EVENING AND WILL UPDATE AS NECESSARY.
RIDGING BUILDS EAST OF THE AREA THROUGH THE DAY ON WEDNESDAY...WITH
MOSTLY SUNNY SKIES AND FAIR CONDITIONS. KEPT HIGH TEMPS SLIGHTLY
BELOW MAV...ALTHOUGH UPWARD ADJUSTMENT MAY BE NEEDED IN THE NEXT
FCST WITH WAA INTO THE AREA BY THE AFTERNOON HOURS ON THE WESTERN
PERIPHERY OF THE RIDGE.
&&
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 344 PM EDT TUE SEP 2 2014
THE GFS AND ECMWF HAVE APPEARED TO INITIALIZE THE UPSTREAM SHORT
WAVE WELL AND ALSO SEEM HAVE A REASONABLE TRACK WITH THIS SYSTEM
ACROSS THE CONUS THIS WEEK. THE ECMWF AND GFS HAVE ALSO SHOWN GOOD
CONSISTENCY FROM RUN TO RUN WITH THIS SYSTEM THE PAST SEVERAL RUNS.
LOW LEVEL THETA E AND MOISTURE FLUX WILL INCREASE RAPIDLY WEDNESDAY
NIGHT...ESPECIALLY NORTH AND NORTHWEST OF THE AREA. HAVE ADDED A
SMALL CHANCE FOR THUNDERSTORMS OVERNIGHT WEDNESDAY NIGHT ON THE
LEADING EDGE OF THIS THETA E ADVECTION OVER FAR NORTHWEST AREAS...
ESPECIALLY BERRIEN AND LAPORTE COUNTY. KEPT THURSDAY DRY AS THE
PRIMARY LOW LEVEL FORCING SHIFTS NORTH OF THE AREA AND AS A LOW
LEVEL INVERSION INCREASES AT THE BASE OF A WEAK TO MODERATE ELEVATED
MIXED LAYER. THE GFS MAV/MEX TEMPERATURES HAVE BEEN CONSISTENT AT
GENERALLY 5 TO 10 DEGREES ABOVE NORMAL FOR THURSDAY AND FRIDAY AND
APPEAR ON TRACK WITH 850 MB TEMPERATURES APPROACHING 20C.
THUNDERSTORM CHANCES LOOK BEST OVERNIGHT THURSDAY NIGHT THROUGH
FRIDAY NIGHT AS A COLD FRONT APPROACHES. GIVEN THE TIMING OF THE
FRONT AND SUBSTANTIAL INSTABILITY BY LATE THURSDAY AND FRIDAY
AFTERNOON/EARLY EVENING WITH CAPES AS HIGH AS 2000 TO 3000
J/KG...CONCERN FOR AN UPSTREAM CONVECTIVE COMPLEX TO DROP SOUTHEAST
OR SOUTH INTO THE FORECAST AREA AS RICH THETA E SPREADS OVER THE
AREA. EXPANDED THUNDERSTORM CHANCES THURSDAY NIGHT IN THIS REGARD.
OTHERWISE...KEPT STORM CHANCES FRIDAY AND FRIDAY NIGHT. OTHERWISE...
COOLER AND DRIER CONDITIONS CAN BE EXPECTED FOR THE WEEKEND INTO
NEXT WEEK WITH HIGHS IN THE 70S THROUGH TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 130 AM EDT WED SEP 3 2014
A WEAK SHORT WAVE PASSING THROUGH THE REGION WAS GENERATING SOME
MID LEVEL CLOUDS. THESE SHOULD BE SHORT LIVED WITH VFR TO START
THE TAF PERIOD. LIGHT WINDS AND MOSTLY CLEAR SKIES WILL ALSO ALLOW
BR TO FORM. HAVE ALREADY SEEN SOME PATCHY MVFR AND IFR IN RURAL
AREAS. STILL EXPECT KFWA TO HAVE BEST CHANCE OF SEEING MVFR AND
IFR CONDITIONS OVERNIGHT. FOG SHOULD BURN OFF QUICKLY AFTER
SUNRISE WITH VFR AND SOUTH TO SOUTHWEST WINDS UNDER 10 KNOTS
EXPECTED REMAINDER OF PERIOD.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
UPDATE...FISHER
SYNOPSIS...LASHLEY
SHORT TERM...NG
LONG TERM...SKIPPER
AVIATION...LASHLEY
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AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
948 PM CDT THU SEP 4 2014
.UPDATE...
ISSUED AT 947 PM CDT THU SEP 4 2014
AREA RADAR MOSAIC AT 9 PM WAS SHOWING ELEVATED SHOWERS DEVELOPING
OVER FAR W CENTRAL IA INTO NE NEB...WHERE THE RAP MODEL WAS
SHOWING A WEAKENING IN THE STRONG CAP/ELEVATED MIXED LAYER WITH 14
C PLUS TEMPERATURES AT 700 MB THAT AT 00Z STRETCHED FROM NEW
MEXICO NORTHEAST THROUGH THE CENTRAL PLAINS INTO IA AND NW IL. THE
DEVELOPING CONVECTION WAS BEHIND THE SURFACE FRONT THAT EXTENDED
FROM SE MN THROUGH CHARLES CITY INTO W CENTRAL IA JUST SE OF THE
DES MOINES METRO AREA...WHERE KDMX WAS PAINTING THIS BOUNDARY WITH
A FINE LINE ECHO.
THE STRONG CAP OVERHEAD IS PROJECTED BY THE RAP TO WEAKEN AS A WEAK
SHORTWAVE APPROACHING THE MO RIVER PUSHES INTO EASTERN IA AFTER
09Z. THIS WOULD BE ALONG AND AHEAD OF THE SURFACE FRONT LIKELY TO
BE MOVING INTO EASTERN IA AT THIS TIME. 00Z 850 MB ANALYSIS
SHOWED A VERY MOIST AXIS FROM THE LOWER MS VALLEY NORTH THROUGH
CENTRAL IA AND SE MN...WITH DEWPOINTS ABOVE 16 C AHEAD OF THE COLD
FRONT. PW VALUES FROM 00Z WERE FROM 1.5 TO 1.75 IN THIS AXIS.
THE THETAE CONVERGENCE INTO ANY DEVELOPING CONVECTION...AS SHOWN
BY THE RAP...COULD LEAD TO LOCALLY HEAVY RAINFALL...ESPECIALLY IF
CONVECTION ORGANIZES AS SUGGESTED.
THIS CONVECTIVE EVOLUTION DOES NOT STRAY TOO FAR FROM THE CURRENT
FORECAST...BUT WILL BE MAKING SOME TWEAKS CLOSER TO THIS SOLUTION
IN AN UPDATE OUT SHORTLY. OUT AHEAD OF THE FRONT...WIDESPREAD
DEWPOINTS HOLDING IN THE LOWER AND MID 70S DUE TO CONTINUED
WARM ADVECTION IN THE ON THE LOW LEVEL SOUTHERLY FLOW...WILL KEEP
MINS IN THE LOWER AND POSSIBLY MID 70S IN AREAS OF THE FAR EAST
AND SOUTHEAST NOT AS LIKELY TO SEE RAINFALL OVERNIGHT.
&&
.SYNOPSIS...
ISSUED AT 327 PM CDT THU SEP 4 2014
THE CLUSTER OF THUNDERSTORMS THAT BROUGHT RAIN TO AREA OVERNIGHT
THROUGH EARLY AFTERNOON HAS SHIFTED EAST AND DISSIPATED. AFTERNOON
HEAT INDICES IN AREAS NOT IMPACTED BY THESE STORMS...GENERALLY
SOUTHWEST OF A LINE FROM DBQ TO MLI TO PRINCETON IL HAVE PUSHED
INTO THE UPPER 90S TO LOWER 100S. A COLD FRONT STRETCHES FROM A
SURFACE LOW IN NORTHWEST MN TO FSD AND INTO EASTERN NE. THUNDERSTORMS
IN MN AND NORTHERN WI ARE ASSOCIATED WITH THE WARM FRONT ALSO
EMANATING FROM THE SURFACE LOW.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 327 PM CDT THU SEP 4 2014
MAIN CONCERN IS TIMING THE COLD FRONTAL PASSAGE OVERNIGHT AND THE
ASSOCIATED PRECIP. MODELS AGREE IN BRINGING THE FRONT INTO THE
CWA AFTER 06Z THEN EXITING THE CWA FRIDAY AFTERNOON. MODELS ALSO
AGREE AMONGST EACH OTHER AND WITH CURRENT OBSERVATIONS IN THAT
PRECIP IS AND WILL BE POST FRONTAL. THUS TIMING OF THE FRONT IS
CRITICAL AND DRIVES THE PRECIP CHANCES...AS WELL AS MIN TEMPS
OVERNIGHT WHICH WILL VARY FROM POST FRONTAL IN THE NORTHWEST TO
WARM SECTOR IN THE SOUTHEAST.
AS THE FRONT SLOWS DOWN TOMORROW WITH THE SURFACE LOW WELL TO OUR
NORTH AND SOME WEAK UPPER LEVEL SUPPORT FROM THE PROGRESSIVE
TROUGH...CLOUDS AND PRECIP CHANCES WILL LINGER. I EXPECT THIS TO
BE MORE FALL-LIKE IN NATURE WITH SHOWERS AND EMBEDDED THUNDERSTORMS...
THUS NO SEVERE THREAT. WOLF
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 327 PM CDT THU SEP 4 2014
SPLENDID EARLY FALL WEATHER ARRIVING BY WEEKEND WITH MORE CHANCES OF
SHOWERS AND STORMS EARLY NEXT WEEK.
LONG TERM FORECAST CONFIDENCE...FAIR (AVERAGE) OVERALL. POOR OR BELOW
AVERAGE ON TIMING AND AMOUNTS OF RAIN EVENTS EARLY NEXT WEEK AND WITH
TIMING AND STRENGTH OF COLD TO POSSIBLY MUCH COLDER AIR ARRIVING LATE
NEXT WEEK.
OVERVIEW...INITIALIZATION AND VERIFICATION IS FAIR TO POOR WITH ONGOING
QPF FALLING TODAY AND ALSO WITH ENERGY OFF PACIFIC IMPACTING SW MONSOON
THAT MAY IMPACT AREA EARLY TO MIDDLE OF NEXT WEEK. THE AMOUNT OF LATENT
HEAT RELEASED ALSO MAY WELL IMPACT STRENGTH OF UPPER TROUGH DIVING INTO
PLAINS LATE NEXT WEEK. RUN TO RUN VARIANCES AND INTER-SOLUTION TRENDS
SUPPORTS A 70/30 BLEND OF HI- RES ECMWF WITH GEM WITH ONLY MINOR INPUTS
OF GFS AS HIGH AMOUNTS OF SW MONSOON MOISTURE APPEARS QUESTIONABLE TO
PHASE WITH FRONTAL SYSTEM WED/THU.
FRIDAY NIGHT...KEPT EVENING POPS OF MAINLY LIGHT SHOWERS AS SURFACE
FRONT SLIDES EAST WITH SUBSIDENCE SUPPORTING CLEARING ALL AREAS BETWEEN
MIDNIGHT AND SUNRISE SATURDAY AS COOL AIR MOVES IN. MINS UPPER 40S FAR
NE TO NEAR 60F FAR SE STILL REASONABLE.
SATURDAY AND SUNDAY...BEAUTIFUL EARLY FALL WEATHER AS CANADIAN HIGH
PRESSURE MOVES IN WITH LOWER 70S FOR HIGHS SATURDAY AND MOSTLY MIDDLE
70S ON SUNDAY UNDER A SUNNY SKY. DEWPOINTS IN THE UPPER 40S TO LOWER
50S ALSO SUGGEST PRISTINE EARLY FALL AIR. MINS SUNDAY AM SHOULD BE
IN THE UPPER 40S IN FAVORED LOW LYING LOCATIONS OF ROCK/WAPSI RIVER
VALLEYS AND LOWER 50S ELSEWHERE WITH MONDAY AM LOWS MAINLY IN THE
LOWER 50S. NW WINDS OF 10-20 MPH SATURDAY...BECOMING LIGHT SATURDAY
NIGHT THROUGH SUNDAY NIGHT.
MONDAY...SLIGHTLY WARMER WITH HIGHS AGAIN IN THE UPPER 70S TO AROUND
80 DEGREES SUGGESTED WITH INCREASING CLOUDS LATE AND CHANCE OF LIGHT
SHOWERS FROM THE WEST. SOUTH WINDS OF 5 TO 15 MPH BY AFTERNOON.
MONDAY NIGHT THROUGH WEDNESDAY NIGHT...UNSETTLED WITH CHANCES OF
SHOWERS AND STORMS WITH POOR CONFIDENCE OF PHASING OF MONSOON MOISTURE
AHEAD OF DEVELOPING UPPER LEVEL TROUGH. IF SKIES HAVE LESS CLOUDS
THEN HIGH TEMPERATURES MAY NEED RAISING BY UP TO 5 DEGREES FOR LATER
SHIFTS. FAVORABLE REGIME FOR MODERATE TO LOCALLY LOWER END HEAVY RAIN
AMOUNTS OVER A QUARTER INCH TO AGAIN LOCALLY OVER AN INCH PLUS ARE
SUGGESTED BY FRONTAL PASSAGE WEDNESDAY NIGHT FOR NO WATER ISSUES
SUGGESTED NOR ANY SEVERE RISK. MINS IN THE UPPER 50S TO LOWER 60S.
THURSDAY...COOLER TO POTENTIALLY MUCH COOLER AS STRONG EARLY FALL FRONT
TO PASS. FORECAST HIGHS ARE POSSIBLY 5 PLUS DEGREES TOO HIGH FOR LATER
SHIFTS TO REASSESS...OR POSSIBLY LOW/MID 60S. MINS FRIDAY MORNING AS
LOW AS THE LOW/MID 40S SUGGESTED...OR 3-5 DEGREES COLDER THAN THIS FORECAST.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 625 PM CDT THU SEP 4 2014
A COLD FRONT MOVING INTO NORTHWEST IOWA THIS AFTERNOON WILL PUSH
SOUTHEAST THROUGH THE TERMINALS LATE TONIGHT AND EARLY FRIDAY MORNING.
SHOWERS AND A FEW THUNDERSTORMS WILL FOLLOW THE FRONT LATE
TONIGHT...WHICH HAS BEEN HANDLED WITH PROB30 WORDING AT CID AND
DBQ...WITH VICINITY SHOWERS ELSEWHERE. THERE IS A LOW POTENTIAL
FOR SCATTERED THUNDERSTORMS AHEAD OF THE FRONT LATER THIS
EVENING...WHICH IS TOO UNCERTAIN TO INCLUDE IN THE FORECASTS. LOW
CLOUDS BEHIND THE FRONT ARE EXPECTED TO RESULT IN MVFR CIGS FOR A
PERIOD FRIDAY MORNING. THERE WILL ALSO BE SCATTERED RAIN
SHOWERS FRIDAY...BUT CONFIDENCE IN COVERAGE AND TIMING IS TOO LOW
IN THESE OUTER PERIODS TO INCLUDE IN THE TAFS BEYOND VICINITY
WORDING.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...SHEETS
SYNOPSIS...WOLF
SHORT TERM...WOLF
LONG TERM...NICHOLS
AVIATION...SHEETS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
850 PM MDT THU SEP 4 2014
.UPDATE...
ISSUED AT 850 PM MDT THU SEP 4 2014
AT 0240Z SHOWERS/THUNDERSTORMS HAVE INCREASED IN COVERAGE ALONG
AND JUST EAST OF THE CO/KS BORDER AS A WEATHER DISTURBANCE MOVES
IN FROM THE SOUTHWEST. 00Z NAM/RUC SUGGEST THAT THIS AREA OF
PRECIPITATION CONTINUES TO MOVE NORTHEAST THROUGH MIDNIGHT. IT
APPEARS PER 700-500RH THAT ANOTHER DISTURBANCE CURRENTLY OVER
SOUTHEAST COLORADO LIFTS NORTH/NORTHEAST INTO THE AREA AFTER
MIDNIGHT BRINGING HIGHER CHANCES OF RAIN AND A FEW THUNDERSTORMS
TO THE NORTHWEST 1/2-1/3 OF THE AREA. THE HRRR HAS THE HIGHER POPS
TO THE SOUTHEAST OF THIS LINE. SO...CONFIDENCE IS A BIT SHAKY AS
TO HOW THINGS DEVELOP AFTER MIDNIGHT. NO MAJOR ADJUSTMENTS MADE
THIS EVENING. DID INCREASE CLOUDINESS QUITE A BIT. OVERNIGHT LOWS
IN THE 50S STILL LOOKS GOOD AS DO THE NORTHEAST WINDS OF 10 TO 15
MPH.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 158 PM MDT THU SEP 4 2014
WV LOOP AND RAP ANALYSIS SHOWS EXPANSIVE UPPER RIDGE JUST TO OUR
SOUTHEAST WITH PLUME OF MID LEVEL MOISTURE MOVING NORTHEASTWARD
ACROSS THE SOUTHWEST CONUS IN TO THE CENTRAL ROCKIES. CIRRUS WAS
OVERSPREADING THE CENTRAL HIGH PLAINS. AHEAD OF AN EASTWARD MOVING
POSITIVELY TILTED SHORTWAVE TROUGH OVER THE NORTHERN PLAINS. A COLD
FRONT FORCED BY THE AFOREMENTIONED TROUGH HAS MADE IT THROUGH THE
FORECAST AREA AND TEMPERATURES WERE NOTICEABLY COOLER THAN 24 HOURS
PRIOR. MID TO UPPER 70S WERE COMMON IN THE NORTHWEST HALF OF THE
FORECAST AREA WHICH SAW THE EARLIEST FRONTAL PASSAGE. WINDS
IMMEDIATELY BEHIND THE FRONT GUSTED FROM THE NORTH AT 30-35 MPH BUT
HAVE SUBSIDED SOME THIS AFTERNOON. STILL...DIURNAL HEATING AND
MIXING IS CONTRIBUTING TO GUSTS APPROACHING 30 MPH. WINDS WILL
CONTINUE TO DECREASE THROUGH THE AFTERNOON...ESPECIALLY WHEN MIXING
LESSENS THIS EVENING.
CHALLENGES FOR THE SHORT TERM INCLUDE PRECIPITATION CHANCES THIS
EVENING THROUGH TOMORROW AND THE POSSIBILITY OF MARGINALLY SEVERE
HAIL WITH A FEW OF THE THUNDERSTORMS THIS EVENING. LOCALLY HEAVY
RAINFALL WILL BE POSSIBLE GIVEN PWAT VALUES APPROACHING 2 STANDARD
DEVIATIONS ABOVE CLIMO FOR EARLY SEPTEMBER. EVENT QPF TOTALS WILL BE
AROUND ONE INCH FOR THE FAR SOUTH PORTION OF THE FORECAST AREA
TAPERING TO A TENTH OF AN INCH OR LESS IN THE FAR NORTHWEST PORTION
OF THE AREA. STILL SOME UNCERTAINTY ON QPF AMOUNTS AND EXACT
PLACEMENT OF HEAVIER TOTALS ALTHOUGH SHORT RANGE GUIDANCE HAS COME
INTO BETTER AGREEMENT WITH TIMING.
SHOWERS AND THUNDERSTORMS SHOULD DEVELOP ACROSS THE SOUTHERN PORTION
OF THE AREA NEAR AND JUST NORTH OF THE FRONT LATER THIS EVENING AND
THEN CONTINUE TO DEVELOP NORTHWARD AS ISENTROPIC LIFT INCREASES ON
THE COOL SIDE OF THIS BOUNDARY. THE STRONGEST CONVECTION SHOULD
OCCUR THROUGH THE EVENING AND EARLY TONIGHT BEFORE INSTABILITY
WANES. ISOLATED MARGINALLY SEVERE HAIL SEEMS POSSIBLE GIVEN 30-40
KNOT DEEP LAYER SHEAR AND AROUND 1000 J/KG MUCAPE. THIS THREAT
SHOULD BE CONFINED TO THE SOUTHERN PORTION OF THE AREA. LATER IN THE
NIGHT SHOWERS AND THUNDERSTORMS SHOULD BECOME FAIRLY WIDESPREAD AS
ISENTROPIC LIFT MAXIMIZES OVER THE AREA...PARTICULARLY IN THE
SOUTHEASTERN PORTION WHERE HIGHER QPF AMOUNTS ARE. MODELS HAVE
TRENDED SLOWER SO ENDING TIME OF THE PRECIPITATION EVENT IS A LITTLE
UNCERTAIN BUT BY MID/LATE MORNING THE HEAVIEST PRECIPITATION WILL
HAVE SHIFTED EAST OF THE AREA. SOME SHOWERS WILL LINGER IN THE
SOUTHEAST THROUGH THE AFTERNOON BEFORE THE UPPER LEVEL TROUGH AXIS
MOVES THROUGH.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 158 PM MDT THU SEP 4 2014
FRIDAY NIGHT THERE MAYBE SOME LINGERING RAINFALL OVER THE FAR
EAST/SOUTHEAST PART OF THE AREA AHEAD OF THE DEPARTING 500MB SHORT
WAVE TROUGH. THE RAINFALL SHOULD BE EAST OF THE AREA BY MID TO LATE
EVENING. DUE TO THE LOWEST 50MB OR SO OF THE SOUNDINGS REMAINING
SATURATED THOUGHT ABOUT MENTIONING FOG IN THE FORECAST LATE FRIDAY
NIGHT. HOWEVER LOOKS LIKE THE CLOUD COVER WILL REMAIN OVER THE
AREA. IF SKIES CLEAR OVERNIGHT FOG WILL BE MUCH MORE LIKELY TO
DEVELOP. A SURFACE HIGH MOVES THROUGH THE AREA SO WINDS WILL BECOME
LIGHT AND VARIABLE. WITH A COOL AIR MASS IN PLACE LOWS WILL BE WELL
BELOW NORMAL.
SATURDAY AND SATURDAY NIGHT VERY WEAK RIPPLES IN THE UPPER LEVEL
FLOW MOVE OVER THE AREA. SOUNDINGS SHOW A CAPPED UNSATURATED
ENVIRONMENT SO THESE TWO PERIODS WILL BE DRY. DURING THE DAY THE
SURFACE HIGH MOVES EAST WHICH WILL ALLOW WARMER AIR FROM THE SOUTH
TO MOVE INTO THE AREA. SATURDAY NIGHT WILL BE A FEW DEGREES WARMER
THAN FRIDAY NIGHT.
SUNDAY THROUGH THURSDAY NUMEROUS WEAK UPPER LEVEL DISTURBANCES WILL
MOVE ACROSS THE AREA. LATEST RUN OF MODELS DISAGREES WITH THE
PROGRESSION AND LOCATION OF THE STRONGER UPPER LEVEL SHORT WAVE
TROUGH THAT WILL MOVE THROUGH MONDAY THROUGH TUESDAY...THUS LOWERING
CONFIDENCE OF WHEN/WHERE RAINFALL WILL DEVELOP. TUESDAY THROUGH
WEDNESDAY A STRONGER MORE WELL DEFINED UPPER LEVEL SHORT WAVE TROUGH
WILL MOVE THROUGH THE AREA...SO WILL HAVE HIGHER RAINFALL CHANCES AS
A RESULT. A STRONG COLD FRONT MOVES THROUGH WEDNESDAY EVENING BUT
MOISTURE AND UPPER LEVEL FORCING DO NOT LOOK VERY FAVORABLE FOR
STORM DEVELOPMENT AS THE FRONT MOVES THROUGH.
TEMPERATURES FOR THE PERIOD WILL GRADUALLY WARM THROUGH TUESDAY AS
THE COOLER AIR MASS GRADUALLY MOVES EAST. MID WEEK A STRONG COLD
FRONT MOVES INTO THE AREA WEDNESDAY NIGHT WITH THE COOLER AIR
CONTINUING TO MOVE INTO THE AREA THURSDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 530 PM MDT THU SEP 4 2014
FOR KGLD AND KMCK...VFR CONDITIONS EXPECTED THROUGH 13Z WITH MVFR
AND POSSIBLY IFR CONDITIONS IN RAIN/MIST/LOW CIGS FROM ABOUT 14Z
THROUGH THE REST OF THE TAF PERIOD. SHOWERS/THUNDERSTORMS POSSIBLE
IN THE 02Z-05Z TIMEFRAME THROUGH MUCH OF THE NIGHT INTO EARLY
FRIDAY MORNING. THIS IS IN RESPONSE TO A WEATHER DISTURBANCE AND
LARGE AREA OF MOISTURE MOVING THROUGH THE AREA FROM THE SOUTHWEST.
WINDS THROUGH THE PERIOD GENERALLY FROM THE NORTHEAST AT 8-12KTS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...99
SHORT TERM...BRB
LONG TERM...JTL
AVIATION...99
AREA FORECAST DISCUSSION
NWS GOODLAND KS
530 PM MDT THU SEP 4 2014
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 158 PM MDT THU SEP 4 2014
WV LOOP AND RAP ANALYSIS SHOWS EXPANSIVE UPPER RIDGE JUST TO OUR
SOUTHEAST WITH PLUME OF MID LEVEL MOISTURE MOVING NORTHEASTWARD
ACROSS THE SOUTHWEST CONUS IN TO THE CENTRAL ROCKIES. CIRRUS WAS
OVERSPREADING THE CENTRAL HIGH PLAINS. AHEAD OF AN EASTWARD MOVING
POSITIVELY TILTED SHORTWAVE TROUGH OVER THE NORTHERN PLAINS. A COLD
FRONT FORCED BY THE AFOREMENTIONED TROUGH HAS MADE IT THROUGH THE
FORECAST AREA AND TEMPERATURES WERE NOTICEABLY COOLER THAN 24 HOURS
PRIOR. MID TO UPPER 70S WERE COMMON IN THE NORTHWEST HALF OF THE
FORECAST AREA WHICH SAW THE EARLIEST FRONTAL PASSAGE. WINDS
IMMEDIATELY BEHIND THE FRONT GUSTED FROM THE NORTH AT 30-35 MPH BUT
HAVE SUBSIDED SOME THIS AFTERNOON. STILL...DIURNAL HEATING AND
MIXING IS CONTRIBUTING TO GUSTS APPROACHING 30 MPH. WINDS WILL
CONTINUE TO DECREASE THROUGH THE AFTERNOON...ESPECIALLY WHEN MIXING
LESSENS THIS EVENING.
CHALLENGES FOR THE SHORT TERM INCLUDE PRECIPITATION CHANCES THIS
EVENING THROUGH TOMORROW AND THE POSSIBILITY OF MARGINALLY SEVERE
HAIL WITH A FEW OF THE THUNDERSTORMS THIS EVENING. LOCALLY HEAVY
RAINFALL WILL BE POSSIBLE GIVEN PWAT VALUES APPROACHING 2 STANDARD
DEVIATIONS ABOVE CLIMO FOR EARLY SEPTEMBER. EVENT QPF TOTALS WILL BE
AROUND ONE INCH FOR THE FAR SOUTH PORTION OF THE FORECAST AREA
TAPERING TO A TENTH OF AN INCH OR LESS IN THE FAR NORTHWEST PORTION
OF THE AREA. STILL SOME UNCERTAINTY ON QPF AMOUNTS AND EXACT
PLACEMENT OF HEAVIER TOTALS ALTHOUGH SHORT RANGE GUIDANCE HAS COME
INTO BETTER AGREEMENT WITH TIMING.
SHOWERS AND THUNDERSTORMS SHOULD DEVELOP ACROSS THE SOUTHERN PORTION
OF THE AREA NEAR AND JUST NORTH OF THE FRONT LATER THIS EVENING AND
THEN CONTINUE TO DEVELOP NORTHWARD AS ISENTROPIC LIFT INCREASES ON
THE COOL SIDE OF THIS BOUNDARY. THE STRONGEST CONVECTION SHOULD
OCCUR THROUGH THE EVENING AND EARLY TONIGHT BEFORE INSTABILITY
WANES. ISOLATED MARGINALLY SEVERE HAIL SEEMS POSSIBLE GIVEN 30-40
KNOT DEEP LAYER SHEAR AND AROUND 1000 J/KG MUCAPE. THIS THREAT
SHOULD BE CONFINED TO THE SOUTHERN PORTION OF THE AREA. LATER IN THE
NIGHT SHOWERS AND THUNDERSTORMS SHOULD BECOME FAIRLY WIDESPREAD AS
ISENTROPIC LIFT MAXIMIZES OVER THE AREA...PARTICULARLY IN THE
SOUTHEASTERN PORTION WHERE HIGHER QPF AMOUNTS ARE. MODELS HAVE
TRENDED SLOWER SO ENDING TIME OF THE PRECIPITATION EVENT IS A LITTLE
UNCERTAIN BUT BY MID/LATE MORNING THE HEAVIEST PRECIPITATION WILL
HAVE SHIFTED EAST OF THE AREA. SOME SHOWERS WILL LINGER IN THE
SOUTHEAST THROUGH THE AFTERNOON BEFORE THE UPPER LEVEL TROUGH AXIS
MOVES THROUGH.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 158 PM MDT THU SEP 4 2014
FRIDAY NIGHT THERE MAYBE SOME LINGERING RAINFALL OVER THE FAR
EAST/SOUTHEAST PART OF THE AREA AHEAD OF THE DEPARTING 500MB SHORT
WAVE TROUGH. THE RAINFALL SHOULD BE EAST OF THE AREA BY MID TO LATE
EVENING. DUE TO THE LOWEST 50MB OR SO OF THE SOUNDINGS REMAINING
SATURATED THOUGHT ABOUT MENTIONING FOG IN THE FORECAST LATE FRIDAY
NIGHT. HOWEVER LOOKS LIKE THE CLOUD COVER WILL REMAIN OVER THE
AREA. IF SKIES CLEAR OVERNIGHT FOG WILL BE MUCH MORE LIKELY TO
DEVELOP. A SURFACE HIGH MOVES THROUGH THE AREA SO WINDS WILL BECOME
LIGHT AND VARIABLE. WITH A COOL AIR MASS IN PLACE LOWS WILL BE WELL
BELOW NORMAL.
SATURDAY AND SATURDAY NIGHT VERY WEAK RIPPLES IN THE UPPER LEVEL
FLOW MOVE OVER THE AREA. SOUNDINGS SHOW A CAPPED UNSATURATED
ENVIRONMENT SO THESE TWO PERIODS WILL BE DRY. DURING THE DAY THE
SURFACE HIGH MOVES EAST WHICH WILL ALLOW WARMER AIR FROM THE SOUTH
TO MOVE INTO THE AREA. SATURDAY NIGHT WILL BE A FEW DEGREES WARMER
THAN FRIDAY NIGHT.
SUNDAY THROUGH THURSDAY NUMEROUS WEAK UPPER LEVEL DISTURBANCES WILL
MOVE ACROSS THE AREA. LATEST RUN OF MODELS DISAGREES WITH THE
PROGRESSION AND LOCATION OF THE STRONGER UPPER LEVEL SHORT WAVE
TROUGH THAT WILL MOVE THROUGH MONDAY THROUGH TUESDAY...THUS LOWERING
CONFIDENCE OF WHEN/WHERE RAINFALL WILL DEVELOP. TUESDAY THROUGH
WEDNESDAY A STRONGER MORE WELL DEFINED UPPER LEVEL SHORT WAVE TROUGH
WILL MOVE THROUGH THE AREA...SO WILL HAVE HIGHER RAINFALL CHANCES AS
A RESULT. A STRONG COLD FRONT MOVES THROUGH WEDNESDAY EVENING BUT
MOISTURE AND UPPER LEVEL FORCING DO NOT LOOK VERY FAVORABLE FOR
STORM DEVELOPMENT AS THE FRONT MOVES THROUGH.
TEMPERATURES FOR THE PERIOD WILL GRADUALLY WARM THROUGH TUESDAY AS
THE COOLER AIR MASS GRADUALLY MOVES EAST. MID WEEK A STRONG COLD
FRONT MOVES INTO THE AREA WEDNESDAY NIGHT WITH THE COOLER AIR
CONTINUING TO MOVE INTO THE AREA THURSDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 530 PM MDT THU SEP 4 2014
FOR KGLD AND KMCK...VFR CONDITIONS EXPECTED THROUGH 13Z WITH MVFR
AND POSSIBLY IFR CONDITIONS IN RAIN/MIST/LOW CIGS FROM ABOUT 14Z
THROUGH THE REST OF THE TAF PERIOD. SHOWERS/THUNDERSTORMS POSSIBLE
IN THE 02Z-05Z TIMEFRAME THROUGH MUCH OF THE NIGHT INTO EARLY
FRIDAY MORNING. THIS IS IN RESPONSE TO A WEATHER DISTURBANCE AND
LARGE AREA OF MOISTURE MOVING THROUGH THE AREA FROM THE SOUTHWEST.
WINDS THROUGH THE PERIOD GENERALLY FROM THE NORTHEAST AT 8-12KTS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BRB
LONG TERM...JTL
AVIATION...99
AREA FORECAST DISCUSSION
NWS TOPEKA KS
348 PM CDT Wed Sep 3 2014
.SHORT TERM...(This Evening through Thursday)
Issued at 345 PM CDT WED SEP 3 2014
Water vapor loop shows relatively zonal flow across the Central
Plains with weak disturbances moving through. One vort max appears
to be along the border between northwest KS and southwest NE and
seems to be associated with thunderstorm cluster moving into eastern
Nebraska. HRRR has been the only model that developed convection
into central KS this evening, and has done so for the last several
runs. RAP just recently has forecast precip into same general area
in the next several hours. Meanwhile, all other models are keeping
central and eastern KS dry tonight. Confidence is not high enough
that HRRR is right, and thus have continued with POPs below 20% for
tonight in forecast area.
Good pressure gradient across the area tonight will maintain
southerly winds of 10 to 15 kts most areas. This should help keep
minimum temperatures up in the lower to middle 70s.
On Thursday, more sunshine than today and warm temperature aloft
will allow highs to reach the mid 90s most areas. Combined with
dewpoints generally in the upper 60s to lower 70s, peak afternoon
heat indices should reach the 100 to 105 range. Frontal boundary
approaches northwest corner of our CWA around 21Z on Thursday, thus
the chance of late afternoon thunderstorms is continued in that
area.
.LONG TERM...(Thursday Night through Wednesday)
Issued at 345 PM CDT WED SEP 3 2014
Models are in good agreement that the cold front will traverse the
county warning area Thursday night into midday Friday...although
the GFS is the fastest. Convection that develops along and front
Thursday night will have the greatest impact with coverage and
rainfall amounts across the northern 1/3 of the cwa through sunrise
Friday as the front advances southeastward. Will range pops from
likely in the northwest counties to only a slight chance in the
far southeast near Garnett...then keep higher end chance pops all
areas on Friday along and behind the frontal passage and the
approach of a shortwave trough from the central high plains. This
wave will move east of the cwa early Saturday with diminishing
chances for rain north to south as much drier air overspreads the
area. With the frontal passage/cold air advection/clouds and
precip in the area will see much cooler highs from the upper 60s
around Belleville to the middle 80s south of I 35.
This will set the stage for lows in the 50s most areas Friday night
and Saturday night. With the dry air in place and high pressure
center over the area...will keep the area dry late Saturday through
Sunday with highs in the 70s both days.
With the flow aloft slowly transitioning from northwest on Saturday
to a more unsettled west to southwest flow into next week. As it
does...the chances for more thunderstorms will increase and so
will the high temperatures ahead of the next front which is
expected by early Wednesday as a larger scale upper trough moves
into the plains.
Will introduce pops in the north central by Sunday night and then
across the remainder of the cwa Monday into Wednesday.
Highs will generally be in the 80s...cooling slightly into the upper
70s and lower 80s by Wednesday.
&&
.AVIATION...(For the 18Z TAFs through 18Z Thursday Afternoon)
Issued at 1221 PM CDT WED SEP 3 2014
CIGS rising and clouds are scattering out so VFR conditions
expected through the forecast period. Southerly winds should
increase and be gusty into early evening. Very small chance that
some thunderstorms could develop across central KS this evening
and move toward MHK overnight. But chances too low for TEMPO or
PROB30 in TAF.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GDP
LONG TERM...63
AVIATION...GDP
AREA FORECAST DISCUSSION
NWS GOODLAND KS
244 PM MDT WED SEP 3 2014
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 150 PM MDT WED SEP 3 2014
WARM SOUTHWESTERLY MID LEVEL FLOW AND DEEP MIXING HAS RESULTED IN
SIGNIFICANTLY ABOVE NORMAL TEMPERATURES TODAY WELL INTO THE 90S AT
MOST LOCATIONS. SOME HIGH BASED CU HAS FORMED EARLY THIS AFTERNOON
MAINLY OVER EASTERN COLORADO AND A FEW ISOLATED SHOWERS/STORMS ARE
POSSIBLE LATE THIS AFTERNOON AND EVENING. THE BEST CHANCE WILL BE
THE FAR SOUTHERN PORTION OF THE FORECAST AREA WHERE RAP SOUNDINGS
SHOW DEEP MIXING BUT MORE BOUNDARY LAYER MOISTURE AND INSTABILITY
THAN FURTHER NORTH.
AN UPPER LEVEL SHORTWAVE IS EVIDENT ON WATER VAPOR IMAGERY
OVER THE NORTHERN ROCKIES MOVING EASTWARD. THIS SHORTWAVE WILL MOVE
INTO THE NORTHERN PLAINS TONIGHT FORCING SURFACE CYCLOGENESIS TO
OUR NORTH. TIGHTENING SURFACE PRESSURE GRADIENT WILL RESULT IN
INCREASING WINDS BACKING TO MORE OF A SOUTHERLY DIRECTION THIS
EVENING AND INTO THE NIGHT. SUFFICIENT MIXING AND LESS LOW LEVEL
MOISTURE THAN PREVIOUS NIGHTS SHOULD PRECLUDE A FOG THREAT
OVERNIGHT. A COLD FRONT WILL EVOLVE FROM LEE TROUGHING AND SURGE
SOUTHWARD ACROSS THE FORECAST AREA TOMORROW MORNING BRINGING COOLER
TEMPERATURES. WARM/MOIST ADVECTION OVER SURFACE BOUNDARY WILL RESULT
IN SHOWERS AND THUNDERSTORMS INCREASING BY LATE IN THE DAY TOMORROW
ACROSS THE SOUTHWESTERN PORTION OF THE AREA AND ESPECIALLY JUST
AFTER THE SHORT TERM PERIOD.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 242 PM MDT WED SEP 3 2014
THURSDAY NIGHT AND FRIDAY WIDESPREAD RAINFALL...HEAVY AT TIMES...LOOKS
VERY LIKELY FOR THE AREA.
THURSDAY NIGHT MID AND UPPER LEVEL MIXING RATIOS INCREASE AHEAD OF A
COMPACT UPPER LEVEL SHORT WAVE TROUGH THAT WILL MOVE ACROSS THE AREA
THROUGH THE NIGHT. AHEAD OF THE TROUGH ELEVATED CAPE DEVELOPS AS
THE JET AT 750MB NOSES IN THE FROM THE SOUTHEAST...AND PROGRESSES
NORTHWEST ACROSS MOST OF THE AREA THROUGH THE NIGHT. WITH
ISENTROPIC AS WELL AS SYNOPTIC LIFT OCCURRING ALONG THE NOSE OF THIS
JET...ANTICIPATE ELEVATED STORMS TO DEVELOP ALONG IT BY EARLY
EVENING. ELEVATED CAPE ABOVE 750MB MAY BE AS HIGH AS 2500J/KG ALONG
AND SOUTHEAST OF THE NOSE OF THE 750MB JET...WITH INSTABILITY
DECREASING DRAMATICALLY NORTHWEST OF THE NOSE. IF STORMS ARE ABLE
TO TAP INTO THE HIGHER INSTABILITY HAIL UP TO 2 INCHES IN DIAMETER
WILL BE POSSIBLE DUE TO DEEP LAYER SHEAR OF 35KTS. HOWEVER FURTHER
NORTHWEST OF THE JET NOSE HAIL SIZE WILL TAPPER OFF DRAMATICALLY DUE
TO LITTLE TO NO ELEVATED CAPE. PLACED SEVERE WORDING IN THE
FORECAST WHERE SEVERE STORMS WILL BE MOST LIKELY. IN ADDITION TO
THE LARGE HAIL...MEAN STORM MOTION WILL BE AROUND 20MPH AND WILL BE
PARALLEL TO THE NOSE OF THE 750MB JET. THIS WILL LEAD TO SLOW
MOVING TRAINING STORMS CAPABLE OF PRODUCING HEAVY RAINFALL.
ANTICIPATE STORMS TO START OFF AS MORE SUPER CELLULAR IN THE EVENING
WHEN ELEVATED CAPE IS HIGHEST. OVERNIGHT AS THE ELEVATED
INSTABILITY DIMINISHES AND ICE NUCLEI SEEDING FROM UPWIND STORMS
OCCURS...BELIEVE THE HAIL SIZE WILL BECOME SMALLER THAN ONE INCH IN
DIAMETER. HOWEVER HEAVY RAINFALL WILL BECOME MORE OF A THREAT.
FURTHER NORTHWEST OF THE NOSE OF THE 750MB JET 700-500MB THETA-E
LAPSE RATES INDICATE A CONVECTIVELY UNSTABLE ENVIRONMENT DESPITE THE
LACK OF ELEVATED CAPE. WITH UPPER LEVEL SHORT WAVE TROUGH MOVING
ACROSS MOST OF THE AREA THROUGH THE NIGHT DECIDED TO KEEP THE
RAINFALL CHANCES GOING FOR THE REST OF THE AREA...WITH THE BEST
CHANCE FOR RAINFALL ACTUALLY SHIFTING NORTH TOWARD THE NE BORDER
OVERNIGHT FOLLOWING THE HIGHER 700-500MB MIXING RATIOS AND 700-500MB
FRONTOGENESIS.
ASIDE FROM THE WIDESPREAD RAINFALL...A SECOND SURGE OF COOLER AIR
WILL MOVE INTO THE AREA FROM THE NORTH THROUGH THE NIGHT.
FRIDAY MORNING THE UPPER LEVEL SHORT WAVE TROUGH FROM LAST NIGHT
WILL EXIT THE AREA AS ANOTHER SHORT WAVE TROUGH DEEPENS OVER THE
WESTERN PART OF THE AREA. MEANWHILE THE BAND OF 700-500MB
FRONTOGENESIS STRENGTHENS THROUGH THE DAY AND MOVES EAST ACROSS THE
AREA AHEAD OF THIS SECOND SHORT WAVE TROUGH. CAPE WILL BE AROUND
1000J/KG OR LESS SO DO NOT ANTICIPATE A SEVERE THREAT SINCE THE CAPE
PROFILE WILL BE TALL AND NARROW WHICH FAVORS HEAVY RAINFALL. MEAN
STORM MOTION WILL CONTINUE TO BE AROUND 20MPH ALSO FAVORING HEAVY
RAINFALL. ANTICIPATE THE RAINFALL TO END FROM WEST TO EAST DURING
THE AFTERNOON AS THE UPPER LEVEL SHORT WAVE TROUGH EXITS THE AREA.
DUE TO THE COUPLE ROUNDS OF HEAVY RAINFALL POSSIBLE...A FLASH FLOOD
WATCH MAY BE NEEDED BUT WILL HOLD OFF FOR NOW IN ORDER TO GET A GOOD
HANDLE AS TO WHERE THE FLOODING THREAT WILL BE MOST LIKELY.
FRIDAY EVENING THERE MAY BE SOME LINGERING SHOWERS OVER THE EASTERN
PART OF THE AREA AS THE SHORT WAVE TROUGH MOVES EAST. DURING THE
LATE EVENING AND OVERNIGHT HOURS ANOTHER LESS COMPACT UPPER LEVEL
SHORT WAVE TROUGH WILL MOVE THROUGH THE AREA. CURRENTLY THE SOUTH
HALF TO 1/3 HAS THE BEST LIFT AND INSTABILITY SO WILL HAVE THE
HIGHER RAINFALL CHANCES THERE.
SATURDAY THROUGH WEDNESDAY NUMEROUS UPPER LEVEL SHORT WAVE TROUGHS
MOVE ACROSS THE AREA. TWO STRONGER SHORT WAVE TROUGHS WILL MOVE
THROUGH MONDAY AFTERNOON AND MONDAY NIGHT. AS A RESULT WILL HAVE
HIGHER RAINFALL CHANCES FOR MONDAY NIGHT. OTHERWISE LOW RAINFALL
CHANCES ARE FORECAST FOR VARIOUS PARTS OF THE AREA AS THE WEAKER
UPPER LEVEL DISTURBANCES MOVE THROUGH.
TEMPERATURES FOR THE PERIOD WILL START OFF COOLER THAN NORMAL THEN
GRADUALLY WARM TO NEAR NORMAL AS THE COOLER AIR MASS MOVES EAST OF
THE AREA. WEDNESDAY ANOTHER COLD FRONT WILL MOVE INTO THE AREA
BRINGING BELOW NORMAL TEMPERATURES WITH IT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1136 AM MDT WED SEP 3 2014
LOW STRATUS HAS DEPARTED THE AREA LEAVING CLEAR SKIES. VFR
CONDITIONS WILL PREVAIL THROUGH THE END OF THE TAF PERIOD. THE
SURFACE LEE SIDE TROUGH WILL STRENGTHEN THIS EVENING AND WINDS
SHOULD BACK SLIGHTLY TO A MORE SOUTHERLY DIRECTION AND INCREASE.
GUSTS OVER 20 KNOTS ARE POSSIBLE THIS EVENING AND MUCH OF THE
NIGHT...ESPECIALLY AT KGLD...BEFORE A PERIOD OF LIGHTER WINDS
TOMORROW MORNING. BY MID MORNING A COLD FRONT WILL PASS THROUGH
AND THE WINDS WILL SHIFT TO THE NORTH. GUSTS TO AROUND 25 KNOTS
ARE EXPECTED THROUGH LATE MORNING IMMEDIATELY BEHIND THE FRONT.
EXTENSIVE CLOUDS AND PRECIPITATION WILL HOLD OFF UNTIL WELL AFTER
THE END OF THE TAF PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BRB
LONG TERM...JTL
AVIATION...BRB
AREA FORECAST DISCUSSION
NWS GOODLAND KS
150 PM MDT WED SEP 3 2014
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 150 PM MDT WED SEP 3 2014
WARM SOUTHWESTERLY MID LEVEL FLOW AND DEEP MIXING HAS RESULTED IN
SIGNIFICANTLY ABOVE NORMAL TEMPERATURES TODAY WELL INTO THE 90S AT
MOST LOCATIONS. SOME HIGH BASED CU HAS FORMED EARLY THIS AFTERNOON
MAINLY OVER EASTERN COLORADO AND A FEW ISOLATED SHOWERS/STORMS ARE
POSSIBLE LATE THIS AFTERNOON AND EVENING. THE BEST CHANCE WILL BE
THE FAR SOUTHERN PORTION OF THE FORECAST AREA WHERE RAP SOUNDINGS
SHOW DEEP MIXING BUT MORE BOUNDARY LAYER MOISTURE AND INSTABILITY
THAN FURTHER NORTH.
AN UPPER LEVEL SHORTWAVE IS EVIDENT ON WATER VAPOR IMAGERY
OVER THE NORTHERN ROCKIES MOVING EASTWARD. THIS SHORTWAVE WILL MOVE
INTO THE NORTHERN PLAINS TONIGHT FORCING SURFACE CYCLOGENESIS TO
OUR NORTH. TIGHTENING SURFACE PRESSURE GRADIENT WILL RESULT IN
INCREASING WINDS BACKING TO MORE OF A SOUTHERLY DIRECTION THIS
EVENING AND INTO THE NIGHT. SUFFICIENT MIXING AND LESS LOW LEVEL
MOISTURE THAN PREVIOUS NIGHTS SHOULD PRECLUDE A FOG THREAT
OVERNIGHT. A COLD FRONT WILL EVOLVE FROM LEE TROUGHING AND SURGE
SOUTHWARD ACROSS THE FORECAST AREA TOMORROW MORNING BRINGING COOLER
TEMPERATURES. WARM/MOIST ADVECTION OVER SURFACE BOUNDARY WILL RESULT
IN SHOWERS AND THUNDERSTORMS INCREASING BY LATE IN THE DAY TOMORROW
ACROSS THE SOUTHWESTERN PORTION OF THE AREA AND ESPECIALLY JUST
AFTER THE SHORT TERM PERIOD.
.LONG TERM...(SATURDAY THROUGH TUESDAY)
ISSUED AT 251 AM MDT WED SEP 3 2014
SEASONABLE PATTERN FOR THE FIRST WEEKEND OF SEPTEMBER WITH SOME LOW
CHANCES FOR PRECIP AND HIGHS RANGING FROM THE LOW 70S TO MID 80S.
ON THE SYNOPTIC SCALE AN UPPER RIDGE OVER WEST TEXAS/EAST NEW MEXICO
WILL GRADUALLY WEAKEN OVER THE WEEKEND. MODELS IN GENERALLY GOOD
AGREEMENT AT MID-LEVELS FOR A NORTHWEST TO ZONAL TO SOUTHWESTERLY
FLOW OVER THE WEEKEND...THOUGH SIGNIFICANT DIFFERENCES DEVELOP BY
LATE MONDAY ON THE TIMING OF MID-LEVEL SHORTWAVE TROUGHS. ECMWF
SEEMS TO PREFER A MORE ORGANIZED TROUGH AXIS MOVING THROUGH THE
CENTRAL HIGH PLAINS LATE MONDAY INTO EARLY TUESDAY...WHILE GFS
DEPICTS MORE NUMEROUS WEAK IMPULSES WHICH MAKE IT MORE DIFFICULT TO
FORECAST THE FINE-SCALE DETAILS.
AT THE SURFACE HIGH PRESSURE WILL DEVELOP ACROSS THE CENTRAL AND
NORTHERN PLAINS ON SATURDAY...DRIFTING EASTWARD INTO THE UPPER
MIDWEST ON SUNDAY. A NORTH-SOUTH ORIENTED SURFACE TROUGH WILL
DEVELOP NEAR THE KANSAS-COLORADO BORDER SUNDAY AND MONDAY RESULTING
IN BREEZY CONDITIONS AND OFFERING A FOCUS FOR STORMS TO DEVELOP EACH
DAY.
SATURDAY AND SUNDAY...REDUCED POPS SIGNIFICANTLY IN COLLABORATION
WITH NEIGHBORS AS IT APPEARS COLD FRONT WILL BE FARTHER SOUTH THAN
PREVIOUSLY THOUGHT. WITH NO LARGE-SCALE FORCING IN PLAY IT LOOKS
LIKE JUST A FEW DIURNALLY-DRIVEN SHOWERS/STORMS POSSIBLE ON SUNDAY
AFTERNOON. ALSO...AS SFC HIGH PRESSURE MOVES EAST SATURDAY INTO
SUNDAY THERE WILL BE LOW/MID LEVEL MOISTURE ADVECTION FROM THE
SOUTHWEST LEADING TO A CLOUDY DAY TO START MONDAY...LIMITING HEATING
AND THEREFOR FURTHER REDUCING THE LIKELIHOOD OF SHOWERS/STORMS ON
SUNDAY.
MONDAY/TUESDAY...BREEZY ON MONDAY WITH A SURFACE TROUGH DEVELOPING
AS PREVIOUSLY MENTIONED. ECMWF CLEARLY BRINGS A MID-LEVEL SHORTWAVE
TROUGH ACROSS THE REGION LATE MONDAY INTO TUESDAY WHILE THE
DETERMINISTIC GFS JUST DEPICTS A SERIES OF SUBTLE IMPULSES MOVING
FROMM EST TO EAST ACROSS THE ENTIRE GREAT PLAINS REGION. A NUMBER OF
GEFS MEMBERS DEPICT A PATTERN SIMILAR TO THE ECMWF DURING THIS
PERIOD...SO ULTIMATELY DECIDED TO KEEP THE TEENS TO 20S POPS. WITH
SOUTHERLY LOW-LEVEL FLOW THROUGH THE SUNDAY/MONDAY/TUESDAY TIMEFRAME
WILL SEE WARM AIR ADVECTION LEADING TO A WARMING TREND IN
TEMPS...WITH HIGHS REACHING THE LOW TO MID 80S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1136 AM MDT WED SEP 3 2014
LOW STRATUS HAS DEPARTED THE AREA LEAVING CLEAR SKIES. VFR
CONDITIONS WILL PREVAIL THROUGH THE END OF THE TAF PERIOD. THE
SURFACE LEE SIDE TROUGH WILL STRENGTHEN THIS EVENING AND WINDS
SHOULD BACK SLIGHTLY TO A MORE SOUTHERLY DIRECTION AND INCREASE.
GUSTS OVER 20 KNOTS ARE POSSIBLE THIS EVENING AND MUCH OF THE
NIGHT...ESPECIALLY AT KGLD...BEFORE A PERIOD OF LIGHTER WINDS
TOMORROW MORNING. BY MID MORNING A COLD FRONT WILL PASS THROUGH
AND THE WINDS WILL SHIFT TO THE NORTH. GUSTS TO AROUND 25 KNOTS
ARE EXPECTED THROUGH LATE MORNING IMMEDIATELY BEHIND THE FRONT.
EXTENSIVE CLOUDS AND PRECIPITATION WILL HOLD OFF UNTIL WELL AFTER
THE END OF THE TAF PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BRB
LONG TERM...JJM
AVIATION...BRB
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
651 AM CDT WED SEP 3 2014
.UPDATE...
ISSUED AT 645 AM CDT WED SEP 3 2014
A NARROW N-S BAND OF WIDELY SCATTERED THUNDERSTORMS DEVELOPED
OVER THE LAST HALF HOUR THROUGH THE HIGHWAY 83 CORRIDOR.THIS
APPEARS TO BE ASSOCIATED WITH AN 850 MB MOISTURE TRANSPORT SIGNAL
ACROSS SOUTHWEST KANSAS. THE HRRR MODEL IS ALSO PICKING UP ON THIS
ACTIVITY AND HAVE UPDATED FOR A MENTION OF THUNDERSTORMS THROUGH
MID MORNING FROM GARDEN CITY TO DODGE CITY AND HAYS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 339 AM CDT WED SEP 3 2014
THE WEAK FRONTAL BOUNDARY THAT WAS RESIDING ALONG THE WESTERN KANSAS-
OKLAHOMA BORDER CONTINUED TO SLOWLY DISSOLVE AS WINDS NORTH OF THE
FRONT WERE STILL VEERING FROM 090 TO 140 AT DDC. WINDS WERE ALSO 10
TO 12 KNOTS WHICH WAS KEEPING THE BOUNDARY LAYER MIXED ENOUGH TO
PREVENT FOG DEVELOPMENT. LOW STRATUS IS ABOUT ALL WE CAN EXPECT
EXCEPT FOR EXTREME WEST-CENTRAL KANSAS, SO WE WILL KEEP AREAS OF
1/2SM FOG CONFINED TO SYRACUSE TO SCOTT CITY AREAS. VERY WARM LOWER
TROPOSPHERIC AIR WILL CONTINUE TO EXPAND NORTH-NORTHEASTWARD THROUGH
THE DAY. HIGHS AROUND 100F ARE LIKELY ALONG/WEST OF HIGHWAY 83 TO
THE COLORADO BORDER. LEE TROUGH CONVERGENCE AXIS WILL SET UP ALONG
THE COLORADO BORDER AS WELL BY MID-LATE AFTERNOON, AND ALL THE
MESOSCALE AND STORM SCALE MODELS (NAM12, WRF-ARW, WRF-NMMB, RAP13,
AND EVEN THE 13-15HR VALID TIMES OF THE LATEST HRRR) SHOW SOME
SEMBLANCE OF CONVECTION INITIATING SOMEWHERE ACROSS THE WESTERN SIX
COUNTIES (HAMILTON-MORTON-STANTON-KEARNY-GRANT-STEVENS), SO WE WILL
INTRODUCE SOME 20-30 POPS IN THIS AREA. GIVEN THE SIGNIFICANT
TEMPERATURE-DEWPOINT SPREADS WITH TEMPS IN THE UPPER 90S/100 AND
DEWPOINTS IN THE LOW TO MID 50S, DRY MICROBURSTS ARE CERTAINLY GOING
TO BE THE GREATEST THREAT FROM CONVECTION...ESPECIALLY ON THE NORTH
SIDE OF CONVECTION WITH OUTFLOW WIND ADDING TO THE BACKGROUND STRONG
SYNOPTIC WINDS (WHICH OUTSIDE OF STORMS WILL BE 20 TO 25 KNOTS
SUSTAINED). GIVEN THE LACK OF ANY LARGE SCALE FORCING FOR ASCENT,
ANY CONVECTION WHICH DEVELOPS SHOULD DISSIPATE NOT TOO LONG AFTER
SUNSET. ANOTHER MILD NIGHT IS FORECAST TONIGHT INTO EARLY THURSDAY
MORNING WITH CONTINUED SOUTH WINDS OF 14 TO 17 KNOTS. THIS WILL KEEP
THE BOUNDARY LAYER MIXED THROUGH THE NIGHT WITH LOWS ONLY DOWN TO 70-
73F FOR MUCH OF SOUTHWEST AND SOUTH CENTRAL KANSAS.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 353 AM CDT WED SEP 3 2014
OVERALL EXPECTATIONS FOR THE EXTENDED PERIOD FORECAST HAVE NOT
CHANGED IN THE LAST DAY, HOWEVER THE SENSIBLE WEATHER IMPACTS MAY
BECOME MORE CLEAR WITH TIME. THURSDAY WILL STILL BE A WARM DAY WITH
SOUTHERLY, SLIGHTLY DOWNSLOPE COMPONENT BREEZY CONDITIONS IN ADVANCE
OF AN APPROACHING COLD FRONT WHICH MAY INFLUENCE THE EXTREME WEST
CENTRAL COUNTIES DURING THE DAY. AGAIN THE NAM WAS FOLLOWED FAIRLY
CLOSE FOR THIS DAY WITH RESPECT TO HIGHS AND CLOUD COVER.
THUNDERSTORMS WILL BECOME A THREAT INTO THE EVENING AS THE FRONT
MOVES THROUGH THE AREA, BUT AGAIN UPPER SUPPORT IS SOMEWHAT LACKING.
POP TRENDS ARE INCREASING INTO THE SATURDAY PERIOD AS WELL AS THE
UPPER WAVE EJECTS ACROSS THE NORTHERN PLAINS, WHICH WILL INCREASE
MID LEVEL BAROCLINICITY ACROSS THE CENTRAL HIGH PLAINS. NAM MODEL
SATURATES THE BOUNDARY LAYER NICELY WITH SOME ELEVATED CAPE AND
UPSLOPE SURFACE FLOW SUGGESTING SHOWERS THUNDERSTORMS AND PROBABLY
FOG DEVELOPMENT AS WELL OVERNIGHT FRIDAY INTO SATURDAY MORNING.
FRIDAY AND SATURDAY WILL BE RELATIVELY COOL DAYS, WHILE CLOUDS AND
SHOWERS/ISOLATED THUNDERSTORMS MAY LINGER INTO SATURDAY EVENING IN
THE SOUTHERN COUNTIES. SHORTWAVE ENERGY IS SHOWN BY THE GFS TO
SPREAD ACROSS THE HIGH PLAINS AGAIN BY MONDAY, BRINGING ADDITIONAL
CHANCES FOR CONVECTION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1259 AM CDT WED SEP 3 2014
THE AVIATION FORECAST THROUGH 12-15Z TIME FRAME WEDNESDAY WILL BE
CHALLENGING. WE WILL MAINTAIN THE PESSIMISTIC FORECAST OF CEILING
FALLING TO AROUND 200-300 FEET AT GCK AND DDC STARTING AROUND 10Z.
THE LIFR CONDITIONS SHOULD EXIST FOR AT LEAST A COUPLE HOURS
BEFORE DRIER AIR MOVES IN FROM THE SOUTHWEST AS LOW LEVEL
SOUTHWEST MOMENTUM INCREASES BY DAYBREAK. FOR NOW, WE WILL KEEP
HYS AWAY FROM THE IFR/LIFR CONDITIONS, BUT THIS IS ALSO A LOW
CONFIDENCE FORECAST WITH AMENDMENTS QUITE POSSIBLE. SOUTHWEST
WINDS WILL INCREASE DURING THE LATE MORNING THROUGH MIDDAY TIME
FRAME, GUSTING TO 30+ KNOTS BY AFTERNOON.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 97 72 96 64 / 10 10 10 40
GCK 98 70 97 61 / 10 30 20 40
EHA 99 68 96 63 / 20 20 10 60
LBL 100 71 97 66 / 10 20 0 40
HYS 98 72 97 61 / 10 10 20 50
P28 97 74 98 70 / 10 10 0 30
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...RUSSELL
SHORT TERM...UMSCHEID
LONG TERM...RUSSELL
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
103 AM CDT WED SEP 3 2014
...UPDATED AVIATION SECTION...
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 344 PM CDT TUE SEP 2 2014
THE MID TO UPPER LEVEL FLOW HAS BECOME ZONAL IN THE WAKE OF THE
MINOR SHORTWAVE TROUGH THAT TRAVERSED THE CENTRAL PLAINS MONDAY
EVENING. THE EFFECTIVE FRONTAL BOUNDARY AFTER ALL OF THE NIGHTTIME
CONVECTION WAS SITUATED ACROSS CENTRAL OKLAHOMA AND SOUTHERN
ARKANSAS. SOUTH OF THIS FRONT, TEMPERATURES WERE ABOVE 90 AS OF 2
PM, BUT ON THE COOL SIDE OF THE FRONT, MOST READINGS WERE IN THE
70S TO LOWER 80S. LEE TROUGHING WILL DEVELOP TONIGHT AND
WEDNESDAY IN RESPONSE TO THE ZONAL FLOW. LATE TONIGHT, WARMER MID
LEVEL TEMPERATURES WILL SPREAD ACROSS SOUTHWEST KANSAS, CAPPING
THE ELEVATED MOIST LAYER. THE NAM INDICATES THAT LOW LEVEL WINDS
WILL BECOME SOUTHERLY AS THE WARM FRONT SHIFTS INTO NORTHERN
KANSAS BY WEDNESDAY MORNING. HOWEVER, THE RAP SHOWS THE BOUNDARY
STILL SITUATED ALONG THE KANSAS/OKLAHOMA BORDER AT 12Z. SINCE WE
MAY MAINTAIN UPSLOPE SOUTHEASTERLY FLOW MOST OF THE NIGHT, I OPTED
TO BRING THE LOW CLOUDS AND FOG BACK IN TOWARD 09Z. A MID LEVEL
CLOUD DECK MAY DEVELOP AS THE LOW LEVEL JET DEVELOPS THIS EVENING
AND AN ELEVATED THUNDERSTORM OR TWO CAN`T BE COMPLETELY RULED OUT
OVER SOUTH CENTRAL KANSAS BEFORE THE STRONG CAPPING INVERSION
DEVELOPS.
ON WEDNESDAY, THE LEE TROUGH WILL BECOME ESTABLISHED ACROSS THE
HIGH PLAINS, WITH A WEAK SURFACE DRYLINE SITUATED ACROSS FAR
WESTERN KANSAS. AN ISOLATED THUNDERSTORM CANNOT BE RULED OUT
LATE IN THE DAY. HIGH TEMPERATURES WILL BE IN THE MID TO HIGH 90S,WITH
SOME READINGS CLOSE TO 100F.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 357 PM CDT TUE SEP 2 2014
A STRONG UPPER LEVEL SHORTWAVE TROUGH OVER THE PACIFIC NORTHWEST
WILL MOVE EASTWARD INTO THE NORTHERN PLAINS AND UPPER MIDWEST BY
FRIDAY. THIS SYSTEM WILL PUSH A COLD FRONT ACROSS WESTERN KANSAS AND
THE CENTRAL PLAINS ON THURSDAY BRINGING THE BEST CHANCES FOR SHOWERS
AND THUNDERSTORMS. THE STRONGEST MID AND UPPER LEVEL WINDS WILL BE
IN NEBRASKA, SO NOT EXPECTING LOTS OF SEVERE WITH THE FRONT. CAPE
VALUES AROUND 2000 J/KG WILL BE SUFFICIENT TO PRODUCE SOME SMALL
HAIL AND STRONG WINDS AS THE COLD FRONT SWEEPS ACROSS WESTERN KANSAS
TO NEAR DODGE CITY BY 7 PM THURSDAY AND THROUGH MEDICINE LODGE BY
AROUND MIDNIGHT.
HIGH TEMPERATURES WILL BE VERY WARM AHEAD OF THE COLD FRONT ON
THURSDAY WITH LOW TO MID AND UPPER 90S FORECAST. HIGHS THEN COOL
INTO THE 70S INTO FRIDAY WITH A CONTINUED CHANCE FOR MAINLY
AFTERNOON THUNDERSTORMS BEHIND THE FRONT IN MOIST SURFACE UPSLOPE
FLOW.
BY MONDAY HIGHS WARM BACK INTO THE 80S AS THE COOL HIGH PRESSURE
AREA MOVES EAST AND WARM SOUTHERLY WINDS INCREASE. MORE THUNDERSTORM
CHANCES CONTINUE INTO TUESDAY WITH DISTURBANCES IN SOUTHWEST FLOW
ALOFT AND UPPER JET.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1259 AM CDT WED SEP 3 2014
THE AVIATION FORECAST THROUGH 12-15Z TIME FRAME WEDNESDAY WILL BE
CHALLENGING. WE WILL MAINTAIN THE PESSIMISTIC FORECAST OF CEILING
FALLING TO AROUND 200-300 FEET AT GCK AND DDC STARTING AROUND 10Z.
THE LIFR CONDITIONS SHOULD EXIST FOR AT LEAST A COUPLE HOURS
BEFORE DRIER AIR MOVES IN FROM THE SOUTHWEST AS LOW LEVEL
SOUTHWEST MOMENTUM INCREASES BY DAYBREAK. FOR NOW, WE WILL KEEP
HYS AWAY FROM THE IFR/LIFR CONDITIONS, BUT THIS IS ALSO A LOW
CONFIDENCE FORECAST WITH AMENDMENTS QUITE POSSIBLE. SOUTHWEST
WINDS WILL INCREASE DURING THE LATE MORNING THROUGH MIDDAY TIME
FRAME, GUSTING TO 30+ KNOTS BY AFTERNOON.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 72 95 64 78 / 0 10 40 40
GCK 70 92 61 76 / 0 20 40 40
EHA 68 94 63 79 / 10 10 60 30
LBL 71 96 66 81 / 10 0 40 40
HYS 72 92 61 72 / 10 20 50 40
P28 74 97 70 83 / 10 0 30 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...FINCH
LONG TERM...KRUSE
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS JACKSON KY
151 AM EDT WED SEP 3 2014
.UPDATE...
ISSUED AT 1020 PM EDT TUE SEP 2 2014
01Z SFC ANALYSIS SHOWS WAKE HIGH PRESSURE OVER MUCH OF EAST KENTUCKY
TRAILING THE LINEAR MCS THAT PASSED THROUGH DURING THE EVENING WITH
STRONG TO SEVERE STORMS THAT PRODUCED MAINLY DAMAGING WIND GUSTS.
THIS SYSTEM HAS ESSENTIALLY WASHED OUT THE FRONT AND PUSHED IT MAINLY
SOUTH AND EAST OF KENTUCKY. HOWEVER...THERE WILL STILL BE SOME
SCATTERED SHOWERS AND PERHAPS A STRAY STORM AROUND THE FAR SOUTHEAST
PORTION OF THE CWA INTO THE NIGHT. THE CLOUDS WILL GRADUALLY THIN AND
CLEAR OVERNIGHT AND THIS WILL LIKELY SET THE STAGE FOR FOG
FORMATION...BECOMING LOCALLY DENSE IN THE VALLEYS BY DAWN. HAVE
INCLUDED THIS ALL IN THE GRIDS WITH THIS UPDATE. ALSO FINE TUNED THE
TEMPS AND DEW POINTS THROUGH MORNING PER THE LATEST OBS...TRENDS...AND
GUIDANCE FROM THE CONSSHORT. THESE HAVE BEEN SENT TO THE NDFD AND WEB
SERVERS. A FRESHENED SET OF ZONES AND HWO HAVE BEEN SENT.
UPDATE ISSUED AT 758 PM EDT TUE SEP 2 2014
THE MAIN LINE OF STORMS IS FINALLY MOVING INTO THE NEIGHBORING
STATES. A SECONDARY TROUGH IS MOVING THROUGH THE BLUEGRASS AND
APPEARS TO BE FALLING APART. THIS SYSTEM WILL CONTINUE TO MOVE TO THE
SOUTH AND EAST AND WILL BE OUT OF THE AREA BY MORNING. HAD TO LOWER
THE TEMPERATURES AS THEY DROPPED DOWN MUCH LOWER THAN EXPECTED AS THE
LINE WENT THROUGH THE AREA. EXPECT FOG TO BE FORMING AS THE SYSTEM
MOVES OUT. IT WILL BE PATCHY...BUT MAINLY DENSE. SOME ISOLATED
SHOWERS MAY DEVELOP BEHIND THE MAIN SYSTEM TONIGHT...SO DID NOT
IMMEDIATELY END THE PRECIPITATION CHANCES. THE REST OF THE FORECAST
IS ON TRACK.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 343 PM EDT TUE SEP 2 2014
A LINE OF THUNDERSTORMS WITH HEAVY RAINS HAS FORMED ALONG AN OLD
OUTFLOW BOUNDARY ACROSS THE MID SECTION OF EASTERN KENTUCKY. SOME OF
THE STORMS HAVE BECOME NEAR SEVERE AND EXPECT SOME SEVERE STORM
WARNINGS TO BE ISSUED DURING THE NEXT FEW HOURS. THE MAIN THREAT
WILL BE WIND GUSTS. ANOTHER CONCERN IS THAT WITH UNIDIRECTIONAL FLOW
AND HIGH PRECIPITABLE WATER...FLOODING CONCERNS WILL BE A REAL ISSUE
THIS AFTERNOON AND EVENING...MAINLY IN THE SOUTHERN HALF OF EASTERN
KENTUCKY AND ESPECIALLY ALONG THE OLD OUTFLOW BOUNDARY. EXPECT THE
FRONT TO PUSH THE PRECIPITATION SOUTH OF THE AREA BY WEDNESDAY
MORNING. IN GENERAL...THE HRRR AND RAP HAVE NOT BEEN DOING TOO WELL
WITH THIS SYSTEM SO FAR. WEDNESDAY FIGURES TO BE A LITTLE MORE
COMFORTABLE AS THE HUMIDITY WILL BE A LITTLE LOWER.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 301 PM EDT TUE SEP 2 2014
THE MODELS BEGIN THE EXTENDED PERIOD IN PRETTY GOOD AGREEMENT ONCE
AGAIN...WITH A RIDGE OF HIGH PRESSURE...BOTH ALOFT AND AT THE
SURFACE...CENTERED OVER THE EASTERN GULF OF MEXICO...ALONG WITH A
WELL DEFINED TROUGH OF LOW PRESSURE ALOFT TAKING SHAPE OVER THE
NORTHERN PLAINS. THE MODELS HAVE THE RIDGE STEADILY BREAKING DOWN
TO BEGIN THE PERIOD...WITH SHOWERS AND STORMS POPPING UP BENEATH IT
ACROSS THE TENNESSEE VALLEY DOWN TO THE GULF AND ACROSS PORTIONS OF
THE SOUTHEASTERN CONUS. AS THE TROUGH EVOLVES AND STRENGTHENS...IT
WILL EJECT OUT OF THE PLAINS WEDNESDAY AND THURSDAY...AND PUSH
ACROSS THE GREAT LAKES AND OHIO VALLEY REGIONS. THE COLD FRONT
TRAILING FROM THIS UPPER LOW WILL END UP BEING OUR WEATHER MAKER FOR
THE UPCOMING WEEKEND. THE FRONT IS EXPECTED TO INTERACT WITH
MOISTURE COMING OFF THE GULF OF MEXICO ON SOUTHWESTERLY WINDS. THE
FRONT WILL HAVE A DIFFICULT TIME MOVING EASTWARD...HOWEVER...AS THE
RIDGE DIGS IN A BIT JUST OFF THE SOUTHEAST COAST AND FLOW ALOFT
BECOMES MORE ZONAL. THERE WILL BE A GOOD CHANCE OF RAIN FRIDAY
MORNING THROUGH SUNDAY MORNING...AS LIFT AND MOISTURE ALONG THE
SLUGGISH FRONT SET OFF REPEATED ROUNDS OF SHOWERS AND STORMS. THE
RAIN SHOULD FINALLY MOVE OUT OF THE AREA SUNDAY EVENING...AS THE
FRONT FINALLY MOVES OUT OF THE AREA.
TEMPERATURES TO BEGIN THE PERIOD LOOK TO BE ABOVE NORMAL...WITH
HIGHS TOPPING OUT AROUND IN THE MID TO UPPER 80S THURSDAY AND
FRIDAY. ONCE THE FRONT STALLS ACROSS THE AREA AND PRECIPITATION
BECOMES MORE WIDESPREAD...TEMPERATURES WILL LIKELY MAX OUT BELOW
NORMAL VALUES SATURDAY THROUGH MONDAY. THE POSITIONING OF THE FRONT
OVER THE WEEKEND WILL ALLOW FOR SOME COOLER AND DRIER AIR TO FILTER
INTO THE AREA. HIGHS ON SATURDAY SHOULD BE JUST BELOW NORMAL...AS
THE BULK OF COOL AIR SHOULD STILL BE TRAPPED NORTH OF THE OHIO
RIVER. ON SUNDAY...HOWEVER...ONCE WINDS HAVE SHIFTED TO THE
NORTH...TEMPERATURES WILL BE QUITE COOL...WITH READINGS PEAKING IN
THE MID TO UPPER 70S FOR MOST LOCATIONS. THE NORTHERLY FLOW WILL
ONLY ALLOW FOR A SMALL WARM UP ON MONDAY...AS HIGHS THAT DAY WILL
LIKELY ONLY TOP OUT IN THE UPPER 70S AND LOWER 80S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 151 AM EDT WED SEP 3 2014
CONDITIONS VARIED WIDELY AT TAF ISSUANCE FROM VLIFR TO VFR. AS
MID/HIGH CLOUDS DECREASE DURING THE NIGHT...WILL EXPECT FOG AND LOW
CLOUDS TO BECOME MORE EXTENSIVE...WITH MOST PLACES SETTLING TO IFR OR
WORSE BY DAWN. SLOW IMPROVEMENT IS FORECAST DURING THE DAY ON
WEDNESDAY...WITH VFR FINALLY RETURNING DURING THE AFTERNOON.
SCATTERED SHOWERS SHOULD ALSO DEVELOP IN THE AFTERNOON...MAINLY NEAR
AND SOUTH OF A LINE FROM SOMERSET TO PIKEVILLE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...JJ
LONG TERM...AR
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS CARIBOU ME
939 AM EDT WED SEP 3 2014
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION THIS MORNING. HIGH PRESSURE
WILL BUILD ACROSS THE REGION LATER TODAY INTO THURSDAY. THE NEXT
COLD FRONT WILL MOVE THROUGH FRIDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
935 AM UPDATE...THE COLD FRONT HAS PUSHED OFFSHORE, AND THE HEAVY
PRECIPITATION THAT AFFECTED THE REGION EARLY THIS MORNING HAS
EXITED INTO CANADA. WHILE DRIER AIR IS WORKING INTO THE REGION,
THERE IS ALSO A WEAK SHORTWAVE IN THE FLOW ALOFT WHICH WILL TREK
ACROSS NORTHERN MAINE THIS AFTERNOON. THIS COMBINED WITH SOME
HEATING COULD BE ENOUGH TO ALLOW CUMULUS AND EVEN A FEW SHOWERS TO
DEVELOP THIS AFTERNOON, MAINLY ACROSS NORTHERN AROOSTOOK COUNTY.
THE HRRR MODEL BACKS UP THIS THINKING. ELSEWHERE, EXPECT JUST
PARTLY TO MOSTLY SUNNY SKIES. HAVE UPDATED THE FORECAST TO
INTRODUCE A SLIGHT CHANCE OF A SHOWER AND ADJUST CLOUD COVER.
OTHERWISE, NO OTHER CHANGES WERE NEEDED.
PREVIOUS DISCUSSION...A COLD FRONT IS CURRENTLY MOVING ACROSS THE REGION. A
LINE OF SHOWERS AND SOME THUNDERSTORMS IS ACCOMPANYING THIS SYSTEM
AS IT MOVES ACROSS THE STATE. BOTH THE NAM AND GFS ARE DOING A
GOOD JOB WITH BOTH PRECIPITATION AND TIMING... SO WILL USE A MODEL
CONSENSUS APPROACH AND BLEND THESE MODELS FOR POP...QPF AND SKY
COVER. BEHIND THE FRONT DRIER CONDITIONS AND A COLDER AIR MASS
WILL MOVE IN FROM HE WEST ALONG WITH STRONG HIGH PRESSURE. BASED
ON VERIFICATION OVER LAST 24 HOURS HAVE USED THE BIAS CORRECTED
RAW BLEND FOR MAXIMUM AND MINIMUM TEMPERATURE AND DEWPOINT.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
HIGH PRES WILL GRAB CONTROL OF THE REGION`S WX RIGHT THROUGH THIS
TERM WITH A COLD FRONT APPROACHING THE REGION FROM THE WEST LATER
IN THE DAY ON FRIDAY. UNTIL THEN, IT LOOKS LIKE WARM TEMPERATURES
FOR EARLY SEPTEMBER W/DAYTIME HIGHS ON THURSDAY IN THE UPPER 70S
TO AROUND 80 WITH EVEN WARMER READINGS ON FRIDAY. WE ARE TALKING
LOW TO MID 80S FOR AFTERNOON HIGHS ON FRIDAY AS A SSW WIND TAKES
HOLD AHEAD OF THE APPROACHING COLD FRONT.
AS FAR AS PRECIP CHANCES, DECIDED TO STAY W/THE DAYCREW`S THINKING
OF DRY CONDITIONS FOR THURSDAY W/A CHANCE OF SHOWERS(30-40%) BY LATE
FRIDAY AFTERNOON AND THIS WILL MAINLY BE ACROSS THE FAR W AND NW
AREAS. SOME OF THE INSTABILITY PARAMETERS SUCH AS 0-6KM SHEAR,
PWATS 1.5+" AND AN INVERTED V TYPE SOUNDING SUGGEST THE THREAT FOR
TSTMS. 0-6KM SHEAR IS FORECAST FROM BOTH THE NAM AND GFS TO BE
AROUND 35 KTS W/GOOD DIRECTIONAL AND SPEED SHEAR NOTED. DECIDED TO
KEEP THE MENTION OF TSTMS IN THERE FOR LATE FRIDAY AFTERNOON. THE
DAYCREW CAN ASSESS THIS FURTHER W/THE LATER MODEL GUIDANCE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE COLD FRONT IS FORECAST TO MOVE ACROSS THE REGION FRIDAY NIGHT
AND STALL ACROSS THE DOWNEAST REGION ON SATURDAY INTO SATURDAY
NIGHT AS IT BECOMES ALIGNED W/THE UPPER FLOW. A WEAK SURFACE LOW
IS SHOWN BY THE GFS AND ECMWF TO DEVELOP ON THE FRONT WHICH WOULD
KEEP THE RAIN GOING A WHILE LONGER. THE ECMWF IS FURTHER N W/THE
RAIN SHIELD WHILE THE GFS AND ITS ENSEMBLE KEEP THE RAIN ACROSS
THE CENTRAL AND DOWNEAST REGION. DECIDED ON A CONSENSUS FOR THIS
CYCLE YIELDING 60% FOR SHOWERS/RAIN ACROSS THE DOWNEAST AND COAST
AND 20-40% FURTHER N.
A COOLER AIRMASS IS EXPECTED SUNDAY INTO EARLY NEXT WEEK AS HIGH
PRES SLIDE SE FROM CENTRAL CANADA. IT WILL BE A NOTICEABLE CHANGE
AS DAYTIME TEMPERATURES ARE FORECAST TO BE SOME 10-15 DEGREES
COOLER THAN THEY HAVE BEEN THIS WEEK.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
NEAR TERM: EXPECT IFR/MVFR CONDITIONS THIS MORNING AS SHOWERS AND
THUNDERSTORMS MOVE THROUGH WITH A COLD FRONT....IMPROVING TO VFR
LATER THIS MORNING AS HIGH PRESSURE AND DRIER AIR MOVES IN FROM
THE WEST.
SHORT TERM: VFR THURSDAY INTO FRIDAY. THE CAVEAT TO THIS WILL BE
THE POTENTIAL FOR SOME SHALLOW FOG ESPECIALLY THURSDAY MORNING
THANKS IN PART TO THE RAINFALL THAT OCCURRED EARLIER. SOME
TERMINALS ESPECIALLY THE NORTHERN SITES COULD SEE A PERIOD OF MVFR
OR PERHAPS IFR IN THE MORNING. PERIODS OF MVFR FOR THE NORTHERN
TAF SITES W/A COLD FROPA FRIDAY EVENING WHILE IFR/MVFR IS
POSSIBLE ACROSS KBGR AND KBHB FRIDAY NIGHT INTO SATURDAY.
&&
.MARINE...
NEAR TERM: HAVE USED THE NAM12 TO INITIALIZE THE SUSTAINED WIND
GRIDS. FOR WAVES: A SOUTHERLY FETCH CONTINUES TO DEVELOP ACROSS
THE GULF OF MAINE AHEAD OF AN APPROACHING COLD FRONT. MOST OF THIS
FETCH IS OVER THE GULF OF MAINE WHERE COLDER AIR TEMPERATURE IS
SUPPRESSING WIND SPEEDS REACHING SURFACE. THIS FETCH IS GENERATING
THE PRIMARY WAVE SYSTEM (SOUTH 3 FEET/7-8 SECONDS). WAVE MODELS
APPEAR TOO HIGH DUE TO BOUNDARY CONDITIONS... SO HAVE INITIALIZED
WAVES WITH NEAR SHORE WAVE MODEL AND WILL ADJUST LOWER BY 20
PERCENT. WAVE FIELD ALSO ACCOMPANIED BY SECONDARY WAVE GROUP FROM
SOUTHEAST 1 FOOT/9-10 SECONDS.
SHORT TERM: NO HEADLINES FORESEEN UNTIL LATER FRIDAY NIGHT INTO
SATURDAY W/ A COLD FRONT SLIDING ACROSS THE WATERS. ATTM, DECIDED
TO STAY W/GUSTS TO 25 KTS AND SEAS CLIMBING TO 6 FT BY EARLY
SATURDAY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HASTINGS/MIGNONE
SHORT TERM...HEWITT
LONG TERM...HEWITT
AVIATION...HASTINGS/MIGNONE/HEWITT
MARINE...HASTINGS/MIGNONE/HEWITT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1052 PM CDT THU SEP 4 2014
.UPDATE...FOR 06Z AVIATION DISCUSSION BELOW
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 339 PM CDT THU SEP 4 2014
TONIGHT-FRIDAY...SLOWLY STANDING DOWN FROM STRONG TO SEVERE
THUNDERSTORMS SEEN OVER THE PAST 24 HOURS. LOW PRES CENTER HAS
PROGRESSED INTO CENTRAL MN WITH A TRAILING CDFNT ENTERING WRN MN.
WMFNT HAS BARELY NUDGED TO THE I-94 CORRIDOR...AND THIS ENTIRE SFC
SYSTEM WILL CONTINUE SHIFTING E THROUGH THIS EVE AND OVERNIGHT.
ANOTHER ROUND OF SCATTERED SHWRS/TSTMS HAS BROKEN OUT THIS AFTN IN
RESPONSE TO A DISSIPATING CAP ALOFT AND A WEAK UPR LVL WAVE
TRAVERSING NEWD FROM CENTRAL SD INTO CENTRAL MN EVIDENT ON WV
SATELLITE IMAGERY. THE STORMS ARE ALSO BREAKING OUT IN THE WARM
SECTOR OF THIS LOW PRES SYSTEM...TAKING ADVANTAGE OF TEMPS REACHING
THE MID 70S TO LWR 80S AND DEWPOINTS HITTING THE LWR 70S. PLENTY OF
CAPE...VIRTUALLY NO CINH...AND DECENT MIDLVL LAPSE RATES MAY WELL
CONTRIBUTE TO SOME STRONGER STORMS PRODUCING SMALL HAIL ALONG WITH
EFFICIENT BURSTS OF RAIN. THAT SAID...THE COVERAGE WILL BE NO MORE
THAN SCATTERED SO HAVE KEPT POPS IN THE CHC CATEGORY THRU THIS EVE.
AS THE CDFNT MAKES PROGRESSION EWD...WINDS WILL CONTINUE TO SHIFT TO
S AND W BY THIS EVE THEN VEER FURTHER TO NW DURG THE OVERNIGHT HRS
INTO FRI. PRECIP WILL GRADUALLY END FROM W TO E...CLOSE TO AROUND
00Z PER HOPWRF/HRRR TRENDS. SOME CLOUD COVER WILL LINGER OVERNIGHT
AND THERE IS A SMALL CHC OF HAVING SOME LOW STRATUS DURG THE EARLY
MRNG HRS AS COLDER SFC AIR WORKS IN. SKIES ARE EXPECTED TO STEADILY
CLEAR OUT DURG THE DAY TMRW AS THE LOW PRES SYSTEM EXITS AND HIGH
PRES FROM WRN CANADA SLIDES INTO THE N-CENTRAL CONUS DURG THE DAY
TMRW. THUS...BEHIND THIS CDFNT...CAA WILL BE IN HIGH GEAR. HIGHS
THIS AFTN IN THE MID 70S TO MID 80S...HELPING PRODUCE HEAT INDEX
VALUES IN THE LOW-MID 90S IN ERN MN INTO WRN WI...WILL CRASH DOWN TO
THE LOW-MID 50S TNGT. WITH DEEPER COLDER AIR EXPECTED WITH THE
ARRIVAL OF MODIFIED CANADIAN HIGH PRES...HIGHS ON FRI ARE NOT EVEN
EXPECTED TO HIT THE 70 DEGREE MARK. WILL LOOK FOR HIGHS IN THE
MID-UPR 60S ON FRI WITH A MIX OF SUN AND CLOUDS.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 339 PM CDT THU SEP 4 2014
NO MAJOR CHANGES TO THE FORECAST. WE STILL EXPECT A COOLER AND DRY
WEEKEND...WITH SLIGHTLY WARMER TEMPERATURES AND BETTER CHANCES FOR
RAIN MON-WED...BEFORE ANOTHER STRONG COLD FRONT MOVES THROUGH LATE
NEXT WEEK.
A COOL CANADIAN AIR MASS WILL REMAIN IN PLACE FRI/SAT/SUN WITH
VERY LITTLE OR NO MOIST LAYERS IN THE ATMOSPHERIC COLUMN THROUGH
MONDAY MORNING. IN FACT...THE AIR MASS WILL BE DRY ENOUGH /EVEN IN
THE BOUNDARY LAYER/ THAT THERE SHOULD BE VERY LITTLE CLOUD COVER
FOR ABOUT 72 HOURS BEGINNING FRIDAY NIGHT AND THAT INCLUDES
AFTERNOON CUMULUS. WE HAVE 0% FOR POPS FOR SEVERAL PERIODS...WHICH
IS SOMEWHAT RARE...BUT IT IS MORE LIKELY TO HAPPEN THIS TIME OF
YEAR COMPARED TO THE OTHER SEASONS. THE DRY PATTERN THIS WEEKEND
SHOULD LEAD TO FAIRLY LARGE DIURNAL TEMPERATURE SPREADS WITH COOL
MORNINGS AND MILD AFTERNOONS.
THE 500MB HEIGHTS BUCKLE ON MONDAY AND BOTH THE 04.12 GFS AND
ECMWF SHOW SHORTWAVE ENERGY APPROACHING MN BY MONDAY MORNING. THIS
ALSO COINCIDES WITH A DEVELOPING SURFACE LOW IN THE HIGH PLAINS
AND AN INCREASE IN THETA-E ADVECTION ACROSS KS/NE/SD/IA. WE START
TO INCREASE THE CHANCES FOR RAIN IN MN ON MONDAY...BUT ADMITTEDLY
MUCH OF THE RAIN MIGHT REMAIN JUST TO OUR SOUTH AND WEST. THE
850-600MB FGEN...WHAT LITTLE THERE IS...DOES WEAKEN QUITE A BIT
BEFORE CHARGING ACROSS THE UPPER MISSISSIPPI RIVER. SO...THE
FORCING ISN`T OVERLY IMPRESSIVE LOCALLY. I`LL SAVE THE LATE WEEK
COLD FRONT DISCUSSION FOR LATER SHIFTS...BUT IT DOES HAVE THE
POTENTIAL TO BE SOME OF THE COOLEST WEATHER WE`VE SEEN IN MN/WI
SINCE MID MAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1052 PM CDT THU SEP 4 2014
THE PRIMARY CONCERN THIS TAF PERIOD IS THE POTENTIAL FOR MVFR CIGS
OVERNIGHT AND FRIDAY MORNING AS A LOBE OF LLVL MOISTURE SWINGS
DOWN ACROSS CENTRAL MN AND WEST CENTRAL WI. THE HIGHEST
PROBABILITY OF A BKN-OVC MVFR DECK IS AT KAXN AND KSTC...CLOSER TO
THE BETTER FETCH OF MOISTURE. HAVE INCLUDED SCT MVFR LEVEL CLOUDS
AT KMSP ON FRIDAY MORNING...AND BKN AT KRNH AND KEAU WHERE 0.5
KMAGL RAP CONDENSATIONAL PRESSURE DEFICITS DECREASE TO BETWEEN 10
AND 20 MB. THEN NORTHWEST WINDS AND DRIER AIR WORK INTO THE AREA
THROUGHOUT THE DAY AND CONTRIBUTE TO SCATTERING LOW CLOUDS BY THE
AFTERNOON WITH ONLY A SCT-BKN HIGH DECK REMAINING. SHOULD THEN SEE
CLEARING ON FRIDAY EVENING. NORTHWEST WINDS CIRCA 8-12KTS PREVAIL
THROUGH FRIDAY...WITH GUSTS INTO THE MID/UPPER TEENS DURING THE
DAYTIME. SPEEDS REDUCE TO AOB 5 KTS ON FRIDAY EVE AND BACK TO
WEST/SOUTHWEST IN DIRECTION.
KMSP...
HAVE KEPT A MENTION OF SCT 2500 FT CLOUDS ON FRIDAY MORNING...BUT
OTHERWISE VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD WITH SCT-
BKN HIGH CLOUDS UNTIL CLEARING COMMENCES AFTER 00Z SAT. NORTHWEST WINDS AT
AROUND 11KTS ON FRIDAY GUST TO AROUND 17 KTS DURING THE AFTERNOON...THEN
DECREASE BELOW 7 KTS FRIDAY EVE.
/OUTLOOK FOR KMSP/
SAT...VFR. WINDS W 5-10 KTS.
SUN...VFR. WINDS SW 5-10 KTS.
MON...MAINLY VFR. CHC MVFR IN SHRA/TSRA. WINDS S 10-15 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JPC
LONG TERM...CLF
AVIATION...LS
AREA FORECAST DISCUSSION
NWS DULUTH MN
1253 PM CDT WED SEP 3 2014
.UPDATE...
ISSUED AT 1251 PM CDT WED SEP 3 2014
UPDATED FOR ONGOING THUNDERSTORMS IN THE ARROWHEAD. THESE STORMS
DEVELOPED ALONG A LINE OF ACCAS IN THE AREA.
UPDATE ISSUED AT 1229 PM CDT WED SEP 3 2014
UPDATED FOR AVIATION DISCUSSION BELOW.
UPDATE ISSUED AT 1110 AM CDT WED SEP 3 2014
UPDATED TO ADD HIGHER POPS TO SOUTHERN COUNTIES OF FCST AREA WITH
PRECIP SLOWLY DRIFTING NORTH.
UPDATE ISSUED AT 950 AM CDT WED SEP 3 2014
UPDATED TO ADJUST POPS ALONG THE SOUTHERN BORDER OF THE FCST AREA
BASED ON NORTHERN EXTENT OF THE PRECIP AREA IN SOUTHERN MN. THERE
IS SOME BACK BUILDING OF THE AREA IN THE SOUTH SO THE QUESTION IS
HOW MUCH WILL THE AREA AFFECT NE MN AND MW WI. IF THERE IS A LONG
ENOUGH BREAK IN THE PRECIP...THIS COULD ALLOW HIGHER DEWPOINTS TO
MOVE UP INTO THE FORECAST AREA. THE SREF AND HRRR IS HINTING AT
SOME DEVELOPMENT ACROSS THE SOUTHERN COUNTIES OF THE FORECAST AREA
AND MOVING NORTH BUT NOT AS MUCH AS EARLIER MODELS THIS MORNING.
THE NEXT 2-4 HOURS WILL INDICATE HOW THE SOUTHERN PRCIP AREA IS
AFFECTING DEVELOPMENT IN THE NORTH.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT WED SEP 3 2014
THE FOCUS IS ON THE POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS
THIS AFTERNOON AND TONIGHT. AT THE TIME OF THIS WRITING...THE
STORM PREDICTION CENTER HAD A SLIGHT RISK OF SEVERE STORMS OVER
MOST OF THE FORECAST AREA TODAY...WITH EXCEPTION OF THE FAR NORTH.
THERE IS THE POTENTIAL FOR LARGE HAIL...DAMAGING WINDS...HEAVY
RAINFALL...AND EVEN TORNADOES. THE RISK WAS FOR THE SW AND SOUTH
CENTRAL FORECAST AREA.
A LOW PRESSURE SYSTEM IN THE ROCKIES IS EXPECTED TO MOVE INTO THE
NORTHERN HIGH PLAINS THIS MORNING AND GRADUALLY ORGANIZE AS IT
MOVES INTO WESTERN SOUTH DAKOTA THIS AFTERNOON. THERE WILL BE WARM
AND MOIST SOUTHERLY FLOW OVER THE NORTHERN PLAINS AND UPPER
MIDWEST...INCLUDING THE NORTHLAND. THE MODELS ARE PRIMARILY
INDICATING THAT A WARM/STATIONARY FRONT WILL SET UP OVER EASTERN
NORTH DAKOTA AND NORTHERN MINNESOTA. THIS FRONT AND FRONTOGENESIS
ALOFT WILL CONTRIBUTE TO INCREASING CHANCES FOR SHOWERS AND STORMS
IN ITS AREA LATE THIS MORNING AND THIS AFTERNOON. SOME MODELS ARE
ALSO SUGGESTING ANOTHER BOUNDARY...IN THE FORM OF ANOTHER
WARM/STATIONARY FRONT...COULD SET UP ACROSS THE SOUTHERN FORECAST
AREA. THIS OTHER FRONT WILL ALSO AID THE DEVELOPMENT OF SHOWERS
AND STORMS. SOME MODELS PLACE MORE EMPHASIS ON THE NORTHERN
BOUNDARY AND RESULTING SHOWERS AND STORMS...WHILE OTHERS PLACE
MORE EMPHASIS ON THE SOUTHERN BOUNDARY. SINCE THERE COULD BE
INITIAL CAPPING ISSUES OVER THE SOUTHERN FORECAST AREA DUE TO WARM
AIR ALOFT...I HAVE PCPN INCREASING MORE RAPIDLY NEAR THE NORTHERN
BOUNDARY.
THE ENVIRONMENT WILL SUPPORT THE POTENTIAL FOR STRONG TO SEVERE
STORMS OVER MUCH OF THE FORECAST AREA. MIXED LAYER CAPE COULD
APPROACH OR EXCEED 2000 J/KG LATE THIS AFTERNOON AND EARLY THIS
EVENING...WITH THE HIGHER INSTABILITY OVER THE SW AND SOUTHERN
FORECAST AREA. THE COMBINATION OF THIS INSTABILITY AND AT LEAST
30 TO 45 KNOTS OF DEEP LAYER (0-6 KM) WIND SHEAR WILL SUPPORT THE
DEVELOPMENT OF ORGANIZED SUPERCELLS DURING THE LATE AFTERNOON AND
EARLY EVENING. THE GREATEST THREAT OF SEVERE WEATHER APPEARS TO BE
AREAS OF NE MINNESOTA SOUTH OF HIGHWAY 2...INCLUDING THE BRAINERD
LAKES REGION...WHERE INSTABILITY WILL LIKELY BE GREATEST WITH
SUFFICIENT SHEAR AND LOCATED NEAR THE SOUTHERN BOUNDARY. THIS IS
WHERE THERE WILL ALSO BE AN INCREASED POTENTIAL FOR TORNADOES.
MOST OF THE MODELS SUGGEST THAT AFTER THE INITIAL HOURS OF
CONVECTION LATE THIS AFTERNOON AND EARLY THIS EVENING...THAT THE
STORMS COULD FORM A COMPLEX WHICH WOULD LIKELY MOVE EAST...TAPPING
INTO THE STRONG INSTABILITY AND 850 HPA FLOW AND MOISTURE
TRANSPORT ACROSS THE SOUTHERN FORECAST AREA. WHILE THE INITIAL
THREAT OF TODAY MAY BE LARGE HAIL AND TORNADOES...THIS WOULD
PROBABLY TRANSITION TO MORE OF A THREAT OF DAMAGING WINDS. THE
PRECIPITABLE WATER VALUES...WHICH COULD REACH THE 1.75 TO 2 INCH
RANGE...ALSO SUPPORT POTENTIAL HEAVY RAIN. SOME AREAS COULD SEE A
QUICK 1 TO 2 INCHES OF RAIN DEPENDING ON THE DEVELOPMENT AND TRACK
OF STORMS.
THE CHANCES OF SHOWERS AND STORMS WILL DECREASE FROM WEST TO EAST
OVERNIGHT AS AXIS OF THE LOW JET...AND THE MOISTURE TRANSPORT
AXIS...SHIFTS TO THE EAST. THE SURFACE LOW IN WESTERN SOUTH DAKOTA
WILL MOVE TO THE SD/MN BORDER BY LATE IN THE NIGHT...AND ITS
INVERTED TROUGH WILL MOVE TO NEAR THE ND/MN BORDER. THERE ARE LOW
CHANCES OF LINGERING SHOWERS AND STORMS OVER THE FAR NW FORECAST
AREA DUE TO THE LINGERING SUBTLE BOUNDARY OVER NORTHERN MINNESOTA
OR NW ONTARIO AND RESIDUAL FRONTOGENESIS ALOFT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 350 AM CDT WED SEP 3 2014
INITIAL FOCUS FOR LONG TERM IS THE TIMING OF THE COLD FRONT
PASSAGE AND TSTM POTENTIAL THURSDAY. HAVE MADE MINOR ADJUSTMENTS
TO PREVIOUS FCST TO REFINE TIMING OF THE WIND SHIFT/POPS FOR A
SLIGHTLY SLOWER FROPA. LATEST ECM/NAM/GFS ARE ALL IN GOOD
AGREEMENT THE COLD FRONT/SFC LOW REACHES THE WRN MN BORDER
THURSDAY MORNING AROUND DAYBREAK...TRACKS EAST ACROSS NORTH-
CENTRAL MINNESOTA THROUGH THE EARLY AFTERNOON...REACHING LOCATIONS
ALONG A LINE FROM KHIB/KDLH/K04W AROUND 00Z...THEN QUICKLY PASSES
OVER THE NRN WISCONSIN ZONES BY MIDNIGHT.
THIS TIMING WILL POSITION MUCH OF THE FORECAST AREA IN THE WARM
SECTOR WITH INCREASING MOISTURE/DEW POINTS FOR MUCH OF THE DAY
THURSDAY. LATEST GUIDANCE SUGGESTS DEW POINTS REACH THE LOW 70S
ACROSS THE ST CROIX RIVER VALLEY AND ACROSS NORTHERN WISCONSIN. IN
ADDITION...THE RESULTING PRESSURE GRADIENT DUE TO THE APPROACHING
FRONT WILL PROMOTE EAST WINDS OVER LAKE SUPERIOR. HAVE LOWERED
TEMPS AND INTRODUCED AREAS OF FOG FOR LOCATIONS ALONG THE NORTH
SHORE AND WESTERN TIP OF LAKE SUPERIOR TO ACCOUNT FOR THE MARINE
AIR MASS.
THE STRONG BAROCLINIC ZONE AND ABUNDANT MOISTURE WILL SUPPORT
STRONG TO SEVERE THUNDERSTORMS ALONG THE FRONT...MAINLY DURING
THE AFTERNOON/EVENING HOURS THURSDAY. HOWEVER...THE LIMITING
FACTOR WILL BE THE NORTHERN EXTENT OF A A STRONG MID-LEVEL CAP.
LATEST NAM BUFR SOUNDING AT KBRD SHOWS H700-H800 TEMPS AROUND 15C.
FURTHER NORTH...TOWARDS KHIB/KELO TEMPERATURES ARE COOLER...BUT
STILL INTRODUCE A LEVEL OF UNCERTAINTY IN THE ABILITY TO TRIGGER
CONVECTION.
IN THE WAKE OF THE COLD FRONT...H85 WINDS ON THE ORDER OF 30-40 KT
WILL ALLOW MUCH COOLER AND DRIER AIR TO SURGE INTO THE
NORTHLAND. THE COLD AIR ALOFT WILL ALLOW FOR FAVORABLE LOW LEVEL
LAPSE RATES THURSDAY NIGHT TO MAINTAIN A FEW THOUSAND FT MIXED
LAYER. HAVE INCREASED WINDS/GUSTS THURS NIGHT AND MAY NEED TO BE
FURTHER INCREASED ON LATER SHIFTS. AT THIS TIME...A PERIOD OF
WINDS GUSTING AROUND 30-35 KT THURSDAY NIGHT IS EXPECTED OVER MUCH
OF THE DLH FORECAST AREA/LAKE SUPERIOR. THE HIGHEST WIND GUSTS ARE
ANTICIPATED ALONG THE NORTH SHORE OF LAKE SUPERIOR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1229 PM CDT WED SEP 3 2014
LINE OF THUNDERSTORMS TO THE SOUTH WILL SLOWLY ENCROACH UPON THE
REGION THROUGH THE AFTERNOON. MODEL GUIDANCE IS KEEPING THE STORMS
FROM TRACKING TOO FAR NORTH...BUT WILL CLIP BRD AND DLH AND PUSH
ACROSS HYR THROUGH THE EVENING. A SECONDARY LINE OF WEAKER
CONVECTION WILL DEVELOP OVER NE MN THIS AFTERNOON AND LINGER OVER
THE REGION TONIGHT AS WELL. WILL LIKELY SEE FOG DEVELOP BEHIND THE
SYSTEM WITH LIFR CIGS/VSBYS AND SOME -DZ POSSIBLE ALONG THE NORTH
SHORE AND AROUND DLH. A FEW LIGHT RAIN SHOWERS ARE POSSIBLE
THURSDAY MORNING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 75 62 70 55 / 60 70 40 10
INL 76 57 72 46 / 40 50 50 30
BRD 78 64 76 50 / 70 90 20 20
HYR 78 66 83 52 / 50 90 60 20
ASX 79 63 81 53 / 50 70 70 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
UPDATE...STEWART
SHORT TERM...GROCHOCINSKI
LONG TERM...GRANING
AVIATION...BJT
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1229 PM CDT WED SEP 3 2014
.UPDATE...
ISSUED AT 1229 PM CDT WED SEP 3 2014
UPDATED FOR AVIATION DISCUSSION BELOW.
UPDATE ISSUED AT 1110 AM CDT WED SEP 3 2014
UPDATED TO ADD HIGHER POPS TO SOUTHERN COUNTIES OF FCST AREA WITH
PRECIP SLOWLY DRIFTING NORTH.
UPDATE ISSUED AT 950 AM CDT WED SEP 3 2014
UPDATED TO ADJUST POPS ALONG THE SOUTHERN BORDER OF THE FCST AREA
BASED ON NORTHERN EXTENT OF THE PRECIP AREA IN SOUTHERN MN. THERE
IS SOME BACK BUILDING OF THE AREA IN THE SOUTH SO THE QUESTION IS
HOW MUCH WILL THE AREA AFFECT NE MN AND MW WI. IF THERE IS A LONG
ENOUGH BREAK IN THE PRECIP...THIS COULD ALLOW HIGHER DEWPOINTS TO
MOVE UP INTO THE FORECAST AREA. THE SREF AND HRRR IS HINTING AT
SOME DEVELOPMENT ACROSS THE SOUTHERN COUNTIES OF THE FORECAST AREA
AND MOVING NORTH BUT NOT AS MUCH AS EARLIER MODELS THIS MORNING.
THE NEXT 2-4 HOURS WILL INDICATE HOW THE SOUTHERN PRCIP AREA IS
AFFECTING DEVELOPMENT IN THE NORTH.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT WED SEP 3 2014
THE FOCUS IS ON THE POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS
THIS AFTERNOON AND TONIGHT. AT THE TIME OF THIS WRITING...THE
STORM PREDICTION CENTER HAD A SLIGHT RISK OF SEVERE STORMS OVER
MOST OF THE FORECAST AREA TODAY...WITH EXCEPTION OF THE FAR NORTH.
THERE IS THE POTENTIAL FOR LARGE HAIL...DAMAGING WINDS...HEAVY
RAINFALL...AND EVEN TORNADOES. THE RISK WAS FOR THE SW AND SOUTH
CENTRAL FORECAST AREA.
A LOW PRESSURE SYSTEM IN THE ROCKIES IS EXPECTED TO MOVE INTO THE
NORTHERN HIGH PLAINS THIS MORNING AND GRADUALLY ORGANIZE AS IT
MOVES INTO WESTERN SOUTH DAKOTA THIS AFTERNOON. THERE WILL BE WARM
AND MOIST SOUTHERLY FLOW OVER THE NORTHERN PLAINS AND UPPER
MIDWEST...INCLUDING THE NORTHLAND. THE MODELS ARE PRIMARILY
INDICATING THAT A WARM/STATIONARY FRONT WILL SET UP OVER EASTERN
NORTH DAKOTA AND NORTHERN MINNESOTA. THIS FRONT AND FRONTOGENESIS
ALOFT WILL CONTRIBUTE TO INCREASING CHANCES FOR SHOWERS AND STORMS
IN ITS AREA LATE THIS MORNING AND THIS AFTERNOON. SOME MODELS ARE
ALSO SUGGESTING ANOTHER BOUNDARY...IN THE FORM OF ANOTHER
WARM/STATIONARY FRONT...COULD SET UP ACROSS THE SOUTHERN FORECAST
AREA. THIS OTHER FRONT WILL ALSO AID THE DEVELOPMENT OF SHOWERS
AND STORMS. SOME MODELS PLACE MORE EMPHASIS ON THE NORTHERN
BOUNDARY AND RESULTING SHOWERS AND STORMS...WHILE OTHERS PLACE
MORE EMPHASIS ON THE SOUTHERN BOUNDARY. SINCE THERE COULD BE
INITIAL CAPPING ISSUES OVER THE SOUTHERN FORECAST AREA DUE TO WARM
AIR ALOFT...I HAVE PCPN INCREASING MORE RAPIDLY NEAR THE NORTHERN
BOUNDARY.
THE ENVIRONMENT WILL SUPPORT THE POTENTIAL FOR STRONG TO SEVERE
STORMS OVER MUCH OF THE FORECAST AREA. MIXED LAYER CAPE COULD
APPROACH OR EXCEED 2000 J/KG LATE THIS AFTERNOON AND EARLY THIS
EVENING...WITH THE HIGHER INSTABILITY OVER THE SW AND SOUTHERN
FORECAST AREA. THE COMBINATION OF THIS INSTABILITY AND AT LEAST
30 TO 45 KNOTS OF DEEP LAYER (0-6 KM) WIND SHEAR WILL SUPPORT THE
DEVELOPMENT OF ORGANIZED SUPERCELLS DURING THE LATE AFTERNOON AND
EARLY EVENING. THE GREATEST THREAT OF SEVERE WEATHER APPEARS TO BE
AREAS OF NE MINNESOTA SOUTH OF HIGHWAY 2...INCLUDING THE BRAINERD
LAKES REGION...WHERE INSTABILITY WILL LIKELY BE GREATEST WITH
SUFFICIENT SHEAR AND LOCATED NEAR THE SOUTHERN BOUNDARY. THIS IS
WHERE THERE WILL ALSO BE AN INCREASED POTENTIAL FOR TORNADOES.
MOST OF THE MODELS SUGGEST THAT AFTER THE INITIAL HOURS OF
CONVECTION LATE THIS AFTERNOON AND EARLY THIS EVENING...THAT THE
STORMS COULD FORM A COMPLEX WHICH WOULD LIKELY MOVE EAST...TAPPING
INTO THE STRONG INSTABILITY AND 850 HPA FLOW AND MOISTURE
TRANSPORT ACROSS THE SOUTHERN FORECAST AREA. WHILE THE INITIAL
THREAT OF TODAY MAY BE LARGE HAIL AND TORNADOES...THIS WOULD
PROBABLY TRANSITION TO MORE OF A THREAT OF DAMAGING WINDS. THE
PRECIPITABLE WATER VALUES...WHICH COULD REACH THE 1.75 TO 2 INCH
RANGE...ALSO SUPPORT POTENTIAL HEAVY RAIN. SOME AREAS COULD SEE A
QUICK 1 TO 2 INCHES OF RAIN DEPENDING ON THE DEVELOPMENT AND TRACK
OF STORMS.
THE CHANCES OF SHOWERS AND STORMS WILL DECREASE FROM WEST TO EAST
OVERNIGHT AS AXIS OF THE LOW JET...AND THE MOISTURE TRANSPORT
AXIS...SHIFTS TO THE EAST. THE SURFACE LOW IN WESTERN SOUTH DAKOTA
WILL MOVE TO THE SD/MN BORDER BY LATE IN THE NIGHT...AND ITS
INVERTED TROUGH WILL MOVE TO NEAR THE ND/MN BORDER. THERE ARE LOW
CHANCES OF LINGERING SHOWERS AND STORMS OVER THE FAR NW FORECAST
AREA DUE TO THE LINGERING SUBTLE BOUNDARY OVER NORTHERN MINNESOTA
OR NW ONTARIO AND RESIDUAL FRONTOGENESIS ALOFT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 350 AM CDT WED SEP 3 2014
INITIAL FOCUS FOR LONG TERM IS THE TIMING OF THE COLD FRONT
PASSAGE AND TSTM POTENTIAL THURSDAY. HAVE MADE MINOR ADJUSTMENTS
TO PREVIOUS FCST TO REFINE TIMING OF THE WIND SHIFT/POPS FOR A
SLIGHTLY SLOWER FROPA. LATEST ECM/NAM/GFS ARE ALL IN GOOD
AGREEMENT THE COLD FRONT/SFC LOW REACHES THE WRN MN BORDER
THURSDAY MORNING AROUND DAYBREAK...TRACKS EAST ACROSS NORTH-
CENTRAL MINNESOTA THROUGH THE EARLY AFTERNOON...REACHING LOCATIONS
ALONG A LINE FROM KHIB/KDLH/K04W AROUND 00Z...THEN QUICKLY PASSES
OVER THE NRN WISCONSIN ZONES BY MIDNIGHT.
THIS TIMING WILL POSITION MUCH OF THE FORECAST AREA IN THE WARM
SECTOR WITH INCREASING MOISTURE/DEW POINTS FOR MUCH OF THE DAY
THURSDAY. LATEST GUIDANCE SUGGESTS DEW POINTS REACH THE LOW 70S
ACROSS THE ST CROIX RIVER VALLEY AND ACROSS NORTHERN WISCONSIN. IN
ADDITION...THE RESULTING PRESSURE GRADIENT DUE TO THE APPROACHING
FRONT WILL PROMOTE EAST WINDS OVER LAKE SUPERIOR. HAVE LOWERED
TEMPS AND INTRODUCED AREAS OF FOG FOR LOCATIONS ALONG THE NORTH
SHORE AND WESTERN TIP OF LAKE SUPERIOR TO ACCOUNT FOR THE MARINE
AIR MASS.
THE STRONG BAROCLINIC ZONE AND ABUNDANT MOISTURE WILL SUPPORT
STRONG TO SEVERE THUNDERSTORMS ALONG THE FRONT...MAINLY DURING
THE AFTERNOON/EVENING HOURS THURSDAY. HOWEVER...THE LIMITING
FACTOR WILL BE THE NORTHERN EXTENT OF A A STRONG MID-LEVEL CAP.
LATEST NAM BUFR SOUNDING AT KBRD SHOWS H700-H800 TEMPS AROUND 15C.
FURTHER NORTH...TOWARDS KHIB/KELO TEMPERATURES ARE COOLER...BUT
STILL INTRODUCE A LEVEL OF UNCERTAINTY IN THE ABILITY TO TRIGGER
CONVECTION.
IN THE WAKE OF THE COLD FRONT...H85 WINDS ON THE ORDER OF 30-40 KT
WILL ALLOW MUCH COOLER AND DRIER AIR TO SURGE INTO THE
NORTHLAND. THE COLD AIR ALOFT WILL ALLOW FOR FAVORABLE LOW LEVEL
LAPSE RATES THURSDAY NIGHT TO MAINTAIN A FEW THOUSAND FT MIXED
LAYER. HAVE INCREASED WINDS/GUSTS THURS NIGHT AND MAY NEED TO BE
FURTHER INCREASED ON LATER SHIFTS. AT THIS TIME...A PERIOD OF
WINDS GUSTING AROUND 30-35 KT THURSDAY NIGHT IS EXPECTED OVER MUCH
OF THE DLH FORECAST AREA/LAKE SUPERIOR. THE HIGHEST WIND GUSTS ARE
ANTICIPATED ALONG THE NORTH SHORE OF LAKE SUPERIOR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1229 PM CDT WED SEP 3 2014
LINE OF THUNDERSTORMS TO THE SOUTH WILL SLOWLY ENCROACH UPON THE
REGION THROUGH THE AFTERNOON. MODEL GUIDANCE IS KEEPING THE STORMS
FROM TRACKING TOO FAR NORTH...BUT WILL CLIP BRD AND DLH AND PUSH
ACROSS HYR THROUGH THE EVENING. A SECONDARY LINE OF WEAKER
CONVECTION WILL DEVELOP OVER NE MN THIS AFTERNOON AND LINGER OVER
THE REGION TONIGHT AS WELL. WILL LIKELY SEE FOG DEVELOP BEHIND THE
SYSTEM WITH LIFR CIGS/VSBYS AND SOME -DZ POSSIBLE ALONG THE NORTH
SHORE AND AROUND DLH. A FEW LIGHT RAIN SHOWERS ARE POSSIBLE
THURSDAY MORNING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 75 62 70 55 / 60 70 40 10
INL 76 57 72 46 / 40 50 50 30
BRD 78 64 76 50 / 70 80 20 20
HYR 78 66 83 52 / 40 80 60 20
ASX 79 63 81 53 / 50 70 70 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...GROCHOCINSKI
LONG TERM...GRANING
AVIATION...BJT
AREA FORECAST DISCUSSION
NWS DULUTH MN
1111 AM CDT WED SEP 3 2014
.UPDATE...
ISSUED AT 1110 AM CDT WED SEP 3 2014
UPDATED TO ADD HIGHER POPS TO SOUTHERN COUNTIES OF FCST AREA WITH
PRECIP SLOWLY DRIFTING NORTH.
UPDATE ISSUED AT 950 AM CDT WED SEP 3 2014
UPDATED TO ADJUST POPS ALONG THE SOUTHERN BORDER OF THE FCST AREA
BASED ON NORTHERN EXTENT OF THE PRECIP AREA IN SOUTHERN MN. THERE
IS SOME BACK BUILDING OF THE AREA IN THE SOUTH SO THE QUESTION IS
HOW MUCH WILL THE AREA AFFECT NE MN AND MW WI. IF THERE IS A LONG
WENOUGH BREAK IN THE PRECIP...THIS COULD ALLOW HIGHER DEWPOINTS TO
MOVE UP INTO THE FORECAST AREA. THE SREF AND HRRR IS HINTING AT
SOME DEVELOPMENT ACROSS THE SOUTHERN COUNTIES OF THE FORECAST AREA
AND MOVING NORTH BUT NOT AS MUCH AS EARLIER MODELS THIS MORNING.
THE NEXT 2-4 HOURS WILL INDICATE HOW THE SOUTHERN PRCIP AREA IS
AFFECTING DEVELOPMENT IN THE NORTH.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT WED SEP 3 2014
THE FOCUS IS ON THE POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS
THIS AFTERNOON AND TONIGHT. AT THE TIME OF THIS WRITING...THE
STORM PREDICTION CENTER HAD A SLIGHT RISK OF SEVERE STORMS OVER
MOST OF THE FORECAST AREA TODAY...WITH EXCEPTION OF THE FAR NORTH.
THERE IS THE POTENTIAL FOR LARGE HAIL...DAMAGING WINDS...HEAVY
RAINFALL...AND EVEN TORNADOES. THE RISK WAS FOR THE SW AND SOUTH
CENTRAL FORECAST AREA.
A LOW PRESSURE SYSTEM IN THE ROCKIES IS EXPECTED TO MOVE INTO THE
NORTHERN HIGH PLAINS THIS MORNING AND GRADUALLY ORGANIZE AS IT
MOVES INTO WESTERN SOUTH DAKOTA THIS AFTERNOON. THERE WILL BE WARM
AND MOIST SOUTHERLY FLOW OVER THE NORTHERN PLAINS AND UPPER
MIDWEST...INCLUDING THE NORTHLAND. THE MODELS ARE PRIMARILY
INDICATING THAT A WARM/STATIONARY FRONT WILL SET UP OVER EASTERN
NORTH DAKOTA AND NORTHERN MINNESOTA. THIS FRONT AND FRONTOGENESIS
ALOFT WILL CONTRIBUTE TO INCREASING CHANCES FOR SHOWERS AND STORMS
IN ITS AREA LATE THIS MORNING AND THIS AFTERNOON. SOME MODELS ARE
ALSO SUGGESTING ANOTHER BOUNDARY...IN THE FORM OF ANOTHER
WARM/STATIONARY FRONT...COULD SET UP ACROSS THE SOUTHERN FORECAST
AREA. THIS OTHER FRONT WILL ALSO AID THE DEVELOPMENT OF SHOWERS
AND STORMS. SOME MODELS PLACE MORE EMPHASIS ON THE NORTHERN
BOUNDARY AND RESULTING SHOWERS AND STORMS...WHILE OTHERS PLACE
MORE EMPHASIS ON THE SOUTHERN BOUNDARY. SINCE THERE COULD BE
INITIAL CAPPING ISSUES OVER THE SOUTHERN FORECAST AREA DUE TO WARM
AIR ALOFT...I HAVE PCPN INCREASING MORE RAPIDLY NEAR THE NORTHERN
BOUNDARY.
THE ENVIRONMENT WILL SUPPORT THE POTENTIAL FOR STRONG TO SEVERE
STORMS OVER MUCH OF THE FORECAST AREA. MIXED LAYER CAPE COULD
APPROACH OR EXCEED 2000 J/KG LATE THIS AFTERNOON AND EARLY THIS
EVENING...WITH THE HIGHER INSTABILITY OVER THE SW AND SOUTHERN
FORECAST AREA. THE COMBINATION OF THIS INSTABILITY AND AT LEAST
30 TO 45 KNOTS OF DEEP LAYER (0-6 KM) WIND SHEAR WILL SUPPORT THE
DEVELOPMENT OF ORGANIZED SUPERCELLS DURING THE LATE AFTERNOON AND
EARLY EVENING. THE GREATEST THREAT OF SEVERE WEATHER APPEARS TO BE
AREAS OF NE MINNESOTA SOUTH OF HIGHWAY 2...INCLUDING THE BRAINERD
LAKES REGION...WHERE INSTABILITY WILL LIKELY BE GREATEST WITH
SUFFICIENT SHEAR AND LOCATED NEAR THE SOUTHERN BOUNDARY. THIS IS
WHERE THERE WILL ALSO BE AN INCREASED POTENTIAL FOR TORNADOES.
MOST OF THE MODELS SUGGEST THAT AFTER THE INITIAL HOURS OF
CONVECTION LATE THIS AFTERNOON AND EARLY THIS EVENING...THAT THE
STORMS COULD FORM A COMPLEX WHICH WOULD LIKELY MOVE EAST...TAPPING
INTO THE STRONG INSTABILITY AND 850 HPA FLOW AND MOISTURE
TRANSPORT ACROSS THE SOUTHERN FORECAST AREA. WHILE THE INITIAL
THREAT OF TODAY MAY BE LARGE HAIL AND TORNADOES...THIS WOULD
PROBABLY TRANSITION TO MORE OF A THREAT OF DAMAGING WINDS. THE
PRECIPITABLE WATER VALUES...WHICH COULD REACH THE 1.75 TO 2 INCH
RANGE...ALSO SUPPORT POTENTIAL HEAVY RAIN. SOME AREAS COULD SEE A
QUICK 1 TO 2 INCHES OF RAIN DEPENDING ON THE DEVELOPMENT AND TRACK
OF STORMS.
THE CHANCES OF SHOWERS AND STORMS WILL DECREASE FROM WEST TO EAST
OVERNIGHT AS AXIS OF THE LOW JET...AND THE MOISTURE TRANSPORT
AXIS...SHIFTS TO THE EAST. THE SURFACE LOW IN WESTERN SOUTH DAKOTA
WILL MOVE TO THE SD/MN BORDER BY LATE IN THE NIGHT...AND ITS
INVERTED TROUGH WILL MOVE TO NEAR THE ND/MN BORDER. THERE ARE LOW
CHANCES OF LINGERING SHOWERS AND STORMS OVER THE FAR NW FORECAST
AREA DUE TO THE LINGERING SUBTLE BOUNDARY OVER NORTHERN MINNESOTA
OR NW ONTARIO AND RESIDUAL FRONTOGENESIS ALOFT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 350 AM CDT WED SEP 3 2014
INITIAL FOCUS FOR LONG TERM IS THE TIMING OF THE COLD FRONT
PASSAGE AND TSTM POTENTIAL THURSDAY. HAVE MADE MINOR ADJUSTMENTS
TO PREVIOUS FCST TO REFINE TIMING OF THE WIND SHIFT/POPS FOR A
SLIGHTLY SLOWER FROPA. LATEST ECM/NAM/GFS ARE ALL IN GOOD
AGREEMENT THE COLD FRONT/SFC LOW REACHES THE WRN MN BORDER
THURSDAY MORNING AROUND DAYBREAK...TRACKS EAST ACROSS NORTH-
CENTRAL MINNESOTA THROUGH THE EARLY AFTERNOON...REACHING LOCATIONS
ALONG A LINE FROM KHIB/KDLH/K04W AROUND 00Z...THEN QUICKLY PASSES
OVER THE NRN WISCONSIN ZONES BY MIDNIGHT.
THIS TIMING WILL POSITION MUCH OF THE FORECAST AREA IN THE WARM
SECTOR WITH INCREASING MOISTURE/DEW POINTS FOR MUCH OF THE DAY
THURSDAY. LATEST GUIDANCE SUGGESTS DEW POINTS REACH THE LOW 70S
ACROSS THE ST CROIX RIVER VALLEY AND ACROSS NORTHERN WISCONSIN. IN
ADDITION...THE RESULTING PRESSURE GRADIENT DUE TO THE APPROACHING
FRONT WILL PROMOTE EAST WINDS OVER LAKE SUPERIOR. HAVE LOWERED
TEMPS AND INTRODUCED AREAS OF FOG FOR LOCATIONS ALONG THE NORTH
SHORE AND WESTERN TIP OF LAKE SUPERIOR TO ACCOUNT FOR THE MARINE
AIR MASS.
THE STRONG BAROCLINIC ZONE AND ABUNDANT MOISTURE WILL SUPPORT
STRONG TO SEVERE THUNDERSTORMS ALONG THE FRONT...MAINLY DURING
THE AFTERNOON/EVENING HOURS THURSDAY. HOWEVER...THE LIMITING
FACTOR WILL BE THE NORTHERN EXTENT OF A A STRONG MID-LEVEL CAP.
LATEST NAM BUFR SOUNDING AT KBRD SHOWS H700-H800 TEMPS AROUND 15C.
FURTHER NORTH...TOWARDS KHIB/KELO TEMPERATURES ARE COOLER...BUT
STILL INTRODUCE A LEVEL OF UNCERTAINTY IN THE ABILITY TO TRIGGER
CONVECTION.
IN THE WAKE OF THE COLD FRONT...H85 WINDS ON THE ORDER OF 30-40 KT
WILL ALLOW MUCH COOLER AND DRIER AIR TO SURGE INTO THE
NORTHLAND. THE COLD AIR ALOFT WILL ALLOW FOR FAVORABLE LOW LEVEL
LAPSE RATES THURSDAY NIGHT TO MAINTAIN A FEW THOUSAND FT MIXED
LAYER. HAVE INCREASED WINDS/GUSTS THURS NIGHT AND MAY NEED TO BE
FURTHER INCREASED ON LATER SHIFTS. AT THIS TIME...A PERIOD OF
WINDS GUSTING AROUND 30-35 KT THURSDAY NIGHT IS EXPECTED OVER MUCH
OF THE DLH FORECAST AREA/LAKE SUPERIOR. THE HIGHEST WIND GUSTS ARE
ANTICIPATED ALONG THE NORTH SHORE OF LAKE SUPERIOR.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 650 AM CDT WED SEP 3 2014
A WARM FRONT WILL LIFT OVER THE FORECAST AREA TODAY...BRINGING
LOWERING CEILINGS AND INCREASING THUNDER CHANCES THROUGH THE
AFTERNOON AND EVENING. BY 06Z...WIDESPREAD MVFR/IFR CONDITIONS
WILL BE FOUND AFTER 06Z AS LOW CLOUDS AND SCATTERED SHOWERS AND
THUNDERSTORMS ARE FOUND ACROSS THE REGION. HAVE BROUGHT IN LIFR
CONDITIONS TO KDLH AFTER 06Z...AS WINDS TURN OUT OF THE EAST AND
ELEVATED DEW POINTS ALLOW FOR FOG/-DZ.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 75 62 70 55 / 60 70 40 10
INL 76 57 72 46 / 40 50 50 30
BRD 78 64 76 50 / 70 80 20 20
HYR 78 66 83 52 / 40 80 60 20
ASX 79 63 81 53 / 50 70 70 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
UPDATE...STEWART
SHORT TERM...GROCHOCINSKI
LONG TERM...GRANING
AVIATION...GRANING
AREA FORECAST DISCUSSION
NWS DULUTH MN
1009 AM CDT WED SEP 3 2014
.UPDATE...
ISSUED AT 950 AM CDT WED SEP 3 2014
UPDATED TO ADJUST POPS ALONG THE SOUTHERN BORDER OF THE FCST AREA
BASED ON NORTHERN EXTENT OF THE PRECIP AREA IN SOUTHERN MN. THERE
IS SOME BACK BUILDING OF THE AREA IN THE SOUTH SO THE QUESTION IS
HOW MUCH WILL THE AREA AFFECT NE MN AND MW WI. IF THERE IS A LONG
WENOUGH BREAK IN THE PRECIP...THIS COULD ALLOW HIGHER DEWPOINTS TO
MOVE UP INTO THE FORECAST AREA. THE SREF AND HRRR IS HINTING AT
SOME DEVELOPMENT ACROSS THE SOUTHERN COUNTIES OF THE FORECAST AREA
AND MOVING NORTH BUT NOT AS MUCH AS EARLIER MODELS THIS MORNING.
THE NEXT 2-4 HOURS WILL INDICATE HOW THE SOUTHERN PRCIP AREA IS
AFFECTING DEVELOPMENT IN THE NORTH.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT WED SEP 3 2014
THE FOCUS IS ON THE POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS
THIS AFTERNOON AND TONIGHT. AT THE TIME OF THIS WRITING...THE
STORM PREDICTION CENTER HAD A SLIGHT RISK OF SEVERE STORMS OVER
MOST OF THE FORECAST AREA TODAY...WITH EXCEPTION OF THE FAR NORTH.
THERE IS THE POTENTIAL FOR LARGE HAIL...DAMAGING WINDS...HEAVY
RAINFALL...AND EVEN TORNADOES. THE RISK WAS FOR THE SW AND SOUTH
CENTRAL FORECAST AREA.
A LOW PRESSURE SYSTEM IN THE ROCKIES IS EXPECTED TO MOVE INTO THE
NORTHERN HIGH PLAINS THIS MORNING AND GRADUALLY ORGANIZE AS IT
MOVES INTO WESTERN SOUTH DAKOTA THIS AFTERNOON. THERE WILL BE WARM
AND MOIST SOUTHERLY FLOW OVER THE NORTHERN PLAINS AND UPPER
MIDWEST...INCLUDING THE NORTHLAND. THE MODELS ARE PRIMARILY
INDICATING THAT A WARM/STATIONARY FRONT WILL SET UP OVER EASTERN
NORTH DAKOTA AND NORTHERN MINNESOTA. THIS FRONT AND FRONTOGENESIS
ALOFT WILL CONTRIBUTE TO INCREASING CHANCES FOR SHOWERS AND STORMS
IN ITS AREA LATE THIS MORNING AND THIS AFTERNOON. SOME MODELS ARE
ALSO SUGGESTING ANOTHER BOUNDARY...IN THE FORM OF ANOTHER
WARM/STATIONARY FRONT...COULD SET UP ACROSS THE SOUTHERN FORECAST
AREA. THIS OTHER FRONT WILL ALSO AID THE DEVELOPMENT OF SHOWERS
AND STORMS. SOME MODELS PLACE MORE EMPHASIS ON THE NORTHERN
BOUNDARY AND RESULTING SHOWERS AND STORMS...WHILE OTHERS PLACE
MORE EMPHASIS ON THE SOUTHERN BOUNDARY. SINCE THERE COULD BE
INITIAL CAPPING ISSUES OVER THE SOUTHERN FORECAST AREA DUE TO WARM
AIR ALOFT...I HAVE PCPN INCREASING MORE RAPIDLY NEAR THE NORTHERN
BOUNDARY.
THE ENVIRONMENT WILL SUPPORT THE POTENTIAL FOR STRONG TO SEVERE
STORMS OVER MUCH OF THE FORECAST AREA. MIXED LAYER CAPE COULD
APPROACH OR EXCEED 2000 J/KG LATE THIS AFTERNOON AND EARLY THIS
EVENING...WITH THE HIGHER INSTABILITY OVER THE SW AND SOUTHERN
FORECAST AREA. THE COMBINATION OF THIS INSTABILITY AND AT LEAST
30 TO 45 KNOTS OF DEEP LAYER (0-6 KM) WIND SHEAR WILL SUPPORT THE
DEVELOPMENT OF ORGANIZED SUPERCELLS DURING THE LATE AFTERNOON AND
EARLY EVENING. THE GREATEST THREAT OF SEVERE WEATHER APPEARS TO BE
AREAS OF NE MINNESOTA SOUTH OF HIGHWAY 2...INCLUDING THE BRAINERD
LAKES REGION...WHERE INSTABILITY WILL LIKELY BE GREATEST WITH
SUFFICIENT SHEAR AND LOCATED NEAR THE SOUTHERN BOUNDARY. THIS IS
WHERE THERE WILL ALSO BE AN INCREASED POTENTIAL FOR TORNADOES.
MOST OF THE MODELS SUGGEST THAT AFTER THE INITIAL HOURS OF
CONVECTION LATE THIS AFTERNOON AND EARLY THIS EVENING...THAT THE
STORMS COULD FORM A COMPLEX WHICH WOULD LIKELY MOVE EAST...TAPPING
INTO THE STRONG INSTABILITY AND 850 HPA FLOW AND MOISTURE
TRANSPORT ACROSS THE SOUTHERN FORECAST AREA. WHILE THE INITIAL
THREAT OF TODAY MAY BE LARGE HAIL AND TORNADOES...THIS WOULD
PROBABLY TRANSITION TO MORE OF A THREAT OF DAMAGING WINDS. THE
PRECIPITABLE WATER VALUES...WHICH COULD REACH THE 1.75 TO 2 INCH
RANGE...ALSO SUPPORT POTENTIAL HEAVY RAIN. SOME AREAS COULD SEE A
QUICK 1 TO 2 INCHES OF RAIN DEPENDING ON THE DEVELOPMENT AND TRACK
OF STORMS.
THE CHANCES OF SHOWERS AND STORMS WILL DECREASE FROM WEST TO EAST
OVERNIGHT AS AXIS OF THE LOW JET...AND THE MOISTURE TRANSPORT
AXIS...SHIFTS TO THE EAST. THE SURFACE LOW IN WESTERN SOUTH DAKOTA
WILL MOVE TO THE SD/MN BORDER BY LATE IN THE NIGHT...AND ITS
INVERTED TROUGH WILL MOVE TO NEAR THE ND/MN BORDER. THERE ARE LOW
CHANCES OF LINGERING SHOWERS AND STORMS OVER THE FAR NW FORECAST
AREA DUE TO THE LINGERING SUBTLE BOUNDARY OVER NORTHERN MINNESOTA
OR NW ONTARIO AND RESIDUAL FRONTOGENESIS ALOFT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 350 AM CDT WED SEP 3 2014
INITIAL FOCUS FOR LONG TERM IS THE TIMING OF THE COLD FRONT
PASSAGE AND TSTM POTENTIAL THURSDAY. HAVE MADE MINOR ADJUSTMENTS
TO PREVIOUS FCST TO REFINE TIMING OF THE WIND SHIFT/POPS FOR A
SLIGHTLY SLOWER FROPA. LATEST ECM/NAM/GFS ARE ALL IN GOOD
AGREEMENT THE COLD FRONT/SFC LOW REACHES THE WRN MN BORDER
THURSDAY MORNING AROUND DAYBREAK...TRACKS EAST ACROSS NORTH-
CENTRAL MINNESOTA THROUGH THE EARLY AFTERNOON...REACHING LOCATIONS
ALONG A LINE FROM KHIB/KDLH/K04W AROUND 00Z...THEN QUICKLY PASSES
OVER THE NRN WISCONSIN ZONES BY MIDNIGHT.
THIS TIMING WILL POSITION MUCH OF THE FORECAST AREA IN THE WARM
SECTOR WITH INCREASING MOISTURE/DEW POINTS FOR MUCH OF THE DAY
THURSDAY. LATEST GUIDANCE SUGGESTS DEW POINTS REACH THE LOW 70S
ACROSS THE ST CROIX RIVER VALLEY AND ACROSS NORTHERN WISCONSIN. IN
ADDITION...THE RESULTING PRESSURE GRADIENT DUE TO THE APPROACHING
FRONT WILL PROMOTE EAST WINDS OVER LAKE SUPERIOR. HAVE LOWERED
TEMPS AND INTRODUCED AREAS OF FOG FOR LOCATIONS ALONG THE NORTH
SHORE AND WESTERN TIP OF LAKE SUPERIOR TO ACCOUNT FOR THE MARINE
AIR MASS.
THE STRONG BAROCLINIC ZONE AND ABUNDANT MOISTURE WILL SUPPORT
STRONG TO SEVERE THUNDERSTORMS ALONG THE FRONT...MAINLY DURING
THE AFTERNOON/EVENING HOURS THURSDAY. HOWEVER...THE LIMITING
FACTOR WILL BE THE NORTHERN EXTENT OF A A STRONG MID-LEVEL CAP.
LATEST NAM BUFR SOUNDING AT KBRD SHOWS H700-H800 TEMPS AROUND 15C.
FURTHER NORTH...TOWARDS KHIB/KELO TEMPERATURES ARE COOLER...BUT
STILL INTRODUCE A LEVEL OF UNCERTAINTY IN THE ABILITY TO TRIGGER
CONVECTION.
IN THE WAKE OF THE COLD FRONT...H85 WINDS ON THE ORDER OF 30-40 KT
WILL ALLOW MUCH COOLER AND DRIER AIR TO SURGE INTO THE
NORTHLAND. THE COLD AIR ALOFT WILL ALLOW FOR FAVORABLE LOW LEVEL
LAPSE RATES THURSDAY NIGHT TO MAINTAIN A FEW THOUSAND FT MIXED
LAYER. HAVE INCREASED WINDS/GUSTS THURS NIGHT AND MAY NEED TO BE
FURTHER INCREASED ON LATER SHIFTS. AT THIS TIME...A PERIOD OF
WINDS GUSTING AROUND 30-35 KT THURSDAY NIGHT IS EXPECTED OVER MUCH
OF THE DLH FORECAST AREA/LAKE SUPERIOR. THE HIGHEST WIND GUSTS ARE
ANTICIPATED ALONG THE NORTH SHORE OF LAKE SUPERIOR.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 650 AM CDT WED SEP 3 2014
A WARM FRONT WILL LIFT OVER THE FORECAST AREA TODAY...BRINGING
LOWERING CEILINGS AND INCREASING THUNDER CHANCES THROUGH THE
AFTERNOON AND EVENING. BY 06Z...WIDESPREAD MVFR/IFR CONDITIONS
WILL BE FOUND AFTER 06Z AS LOW CLOUDS AND SCATTERED SHOWERS AND
THUNDERSTORMS ARE FOUND ACROSS THE REGION. HAVE BROUGHT IN LIFR
CONDITIONS TO KDLH AFTER 06Z...AS WINDS TURN OUT OF THE EAST AND
ELEVATED DEW POINTS ALLOW FOR FOG/-DZ.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 75 62 70 55 / 60 70 40 10
INL 76 57 72 46 / 40 50 50 30
BRD 78 64 76 50 / 70 80 20 20
HYR 78 66 83 52 / 40 80 60 20
ASX 79 63 81 53 / 50 70 70 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
UPDATE...STEWART
SHORT TERM...GROCHOCINSKI
LONG TERM...GRANING
AVIATION...GRANING
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
654 PM CDT THU SEP 4 2014
.SHORT TERM...(TONIGHT THROUGH SUNDAY)
ISSUED AT 310 PM CDT THU SEP 4 2014
CHANCE FOR SHOWERS AND STORMS TONIGHT...AND COOLER TEMPERATURES TO
FOLLOW...ARE THE PRIMARY SHORT RANGE FORECAST CONCERNS.
COLD FRONT WAS SLIPPING SOUTHEAST THROUGH THE CWA THIS AFTERNOON.
LATEST RAP ANALYSIS SHOWS INSTABILITY INCREASING AHEAD OF THE FRONT
WHERE MLCAPES WERE OVER 3000 J/KG ACROSS SOUTHEAST NEBRASKA AND
SOUTHWEST IOWA. HOWEVER WARM MID LEVEL TEMPERATURES WERE PROVIDING A
CAP FOR STORMS AHEAD OF THE FRONT. BEHIND THE FRONT SCATTERED
SHOWERS AND STORMS HAD DEVELOPED IN SOUTHEAST SOUTH DAKOTA TIED TO
WAVE RIDING THROUGH THE NORTHERN PLAINS...BUT THOSE HAD MOVED OFF TO
THE NORTHEAST OR HAD DISSIPATED BY MID AFTERNOON. GIVEN CAPPING
ALONG AND AHEAD OF FRONT...SEEMS UNLIKELY WE WILL SEE DEVELOPMENT
THERE THIS AFTERNOON OR EVENING. BEHIND THE FRONT...MORE DEVELOPMENT
WILL HAVE TO WAIT UNTIL SHORTWAVE CURRENTLY MOVING INTO EASTERN
COLORADO MOVES INTO OUR AREA. LATEST SHORT RANGE MESOSCALE MODELS
SUGGEST THIS WILL NOT HAPPEN UNTIL LATE THIS EVENING...AND FOCUS ON
AREAS NEAR AND NORTHWEST OF INTERSTATE 80...WITH A GRADUAL DRIFT AND
EXPANSION TO THE SOUTHEAST DURING THE OVERNIGHT.
STRONGER MID LEVEL SHORTWAVE PROVIDING MID LEVEL FRONTOGENESIS IS
FORECAST TO OVERSPREAD THE REGION FRIDAY AFTERNOON AND EVENING
BEFORE MOVING OFF TO THE EAST FRIDAY NIGHT. WILL CONTINUE CHANCE FOR
SHOWERS MUCH OF FRIDAY WITH DECREASING CHANCES FRIDAY NIGHT.
SURFACE HIGH PRESSURE WITH NORTHWEST FLOW ALOFT WILL THEN TAKE OVER
AND BRING MILD AND DRY WEATHER FOR THE BULK OF THE WEEKEND. RETURN
FLOW SETTING UP ON SUNDAY COULD SPREAD MORE CLOUDS INTO THE
REGION...BUT WILL KEEP PRECIPITATION OUT OF THE FORECAST THROUGH THE
AFTERNOON.
COOLER WEATHER IS ALSO ON TAP FOR THE WEEKEND. TEMPERATURES AHEAD OF
COLD FRONT WERE IN THE 90S THIS AFTERNOON...WITH 70S OR EVEN 60S
NOTED IN SOUTH DAKOTA IN DEEPER COLD AIR BEHIND THE FRONT
CORRESPONDING TO 10C 850 TEMPERATURES. THAT AIR WILL SETTLE OVER OUR
AREA FRIDAY AND SATURDAY BEFORE WARMING TO NEAR 14C ON SUNDAY. MODEL
OUTPUT AGREES WITH OUR GOING FORECAST FOR UPPER 60S TO LOWER 70S
FRIDAY AND SATURDAY...WITH MID 70S OR SO ON SUNDAY. SEE NO REASON TO
MOVE FROM THOSE NUMBERS TOO MUCH.
.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 310 PM CDT THU SEP 4 2014
UPPER LEVEL FLOW PATTERN WILL BECOME MORE ZONAL FOR THE FIRST HALF
OF THE WEEK BEFORE LARGE UPPER TROUGH SETTLES INTO THE CONUS FOR THE
LATTER HALF. STRONG SHORTWAVE MOVING THROUGH THE PLAINS WILL BRING
RAIN CHANCES TO OUR AREA SUNDAY NIGHT THROUGH MONDAY BEFORE EJECTING
EAST MONDAY NIGHT. RETURN FLOW BEGINNING SUNDAY WILL PROVIDE PLENTY
OF MOISTURE FOR STORMS MONDAY AFTERNOON WHEN SURFACE-BASED CAPES
SHOULD TOP 2000 J/KG AND BULK 0-6KM SHEAR OVER 40KT. SEVERE STORMS
ARE POSSIBLE MONDAY AFTERNOON IF STORMS DO FIRE.
WITH WAVE EXITING TUESDAY...WE SHOULD SEE A DRY PERIOD UNTIL HEIGHTS
BEGIN TO LOWER WEDNESDAY WITH APPROACH OF DEEPER UPPER TROUGH
SETTLING INTO THE PLAINS. CORE OF UPPER TROUGH/LOW WILL MOVE INTO
THE NORTHERN PLAINS BY THURSDAY...AND WILL DRIVE A COLD FRONT
THROUGH OUR AREA WEDNESDAY. ANOTHER CHANCE FOR THUNDERSTORMS WILL
ACCOMPANY THAT FRONT...THEN MAINLY SHOWERS IN OVERRUNNING REGIME
BEHIND THE FRONT FOR WEDNESDAY NIGHT INTO THURSDAY.
TEMPERATURES WILL BE SLOWLY WARMING AHEAD OF WEDNESDAY COLD
FRONT...WITH HIGHS BETWEEN 75 AND 85...THEN MUCH COOLER THURSDAY
WITH HIGHS IN THE 60S.
&&
.AVIATION...(00Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 643 PM CDT THU SEP 4 2014
AVIATION CONCERNS TONIGHT WILL BE COVERAGE/TIMING OF SHOWER AND
THUNDERSTORM ACTIVITY. NOT MUCH ACTIVITY THUS FAR WITH THE COLD
FRONT THAT HAS MOVE THROUGH THE TAF SITES DUE TO THE WARM MID
LEVEL TEMPERATURES. SHOULD SEE SOME SHRA/TSRA DEVELOPMENT IN THE
03-06Z TIME FRAME AT VERTICAL MOTION INCREASES...CAP WEAKENS...AND
DEEP MOISTURE IS IN THE AREA. THIS ACTIVITY LASTS INTO THE
OVERNIGHT AND MORNING HOURS AND SHOULD MAINLY AFFECT THE
KOMA/KLNK SITES. VFR CONDITIONS WILL PREVAIL. SOME LOCAL MVFR
CONDITIONS MAY DEVELOP IN AREAS OF SHRA/TSRA. NORTH WINDS SHOULD
MAINLY BE FROM 6 TO 12KTS.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...DERGAN
LONG TERM...DERGAN
AVIATION...ZAPOTOCNY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1234 PM CDT WED SEP 3 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 417 AM CDT WED SEP 3 2014
UPPER AIR AND SATELLITE DATA SHOWING THE AREA CONTINUING TO BE
INFLUENCED BY ZONAL FLOW...AS HIGH PRESSURE EXTENDS ACROSS THE SRN
CONUS AND BROAD TROUGHING IS IN PLACE NEAR/NORTH OF THE CANADIAN
BORDER...THOUGH AN AREA OF LOW PRESSURE IS PUSHING ITS WAY FURTHER
INLAND FROM THE PAC NW COAST. AS WAS SHOWN BY MODELS...CONVECTION
DEVELOPED EARLIER ACROSS CENTRAL KANSAS...IN RESPONSE TO A WEAK
DISTURBANCE AS WELL AS INCREASED LIFT VIA WARM AIR/MOISTURE
ADVECTION ASSOCIATED WITH A STRONGER LLJ. EARLY ON THE FAR
SOUTHEASTERN CORNER OF MITCHELL COUNTY WAS CLIPPED BY THIS
ACTIVITY...BUT SINCE THEN HAS REMAINED OVER ERN KS. THERE IS A
COUPLE ISOLATED SHOWERS OVER WESTERN KS...AND THE HRRR/RAP HINT AT
SOME ADDITIONAL ACTIVITY POSSIBLY LINGERING INTO THE MID MORNING
HOURS...SO WILL HAVE TO MONITOR HOW THIS ACTIVITY EVOLVES OVER
NEXT FEW HOURS. SATELLITE IMAGERY ALSO SHOWING SOME LOW/MID LEVEL
STRATUS STARTING TO INCREASE IN COVERAGE...BUT MODELS DIFFER SOME
ON HOW EXPANSIVE IT WILL END UP BEING. AT THE SURFACE...THE CWA IS
SET UP BETWEEN HIGH PRESSURE AFFECTING MUCH OF THE ERN CONUS...AND
A TROUGH OF LOW PRESSURE OVER THE HIGH PLAINS. WINDS REMAIN
SOUTHERLY...WITH SPEEDS RANGING FROM 5 TO 15 MPH. TEMPS ARE MORE
MILD THAN 24 HRS AGO...WITH 3 AM TEMPS IN THE MID 60S TO LOWER
70S.
THE MAIN STORY IN THE SHORT TERM PERIOD LIES WITH
TEMPERATURES...AS TODAY IS EXPECTED TO BE THE WARMEST OVER THE
NEXT 7. IN THE UPPER LEVELS...MODELS IN GOOD AGREEMENT SHOWING THE
FLOW TRANSITIONING TO MORE SOUTHWESTERLY AS THAT ABOVE MENTION PAC
NW DISTURBANCE SHIFTS FURTHER EASTWARD INTO THE NRN ROCKIES. WHILE
NOT EXPECTING MUCH IN THE WAY OF PRECIP CHANCES THROUGH TONIGHT
/THOUGH CHANCES ARE NOT ZERO/...THIS PATTERN WILL HELP TO CONTINUE
THE ADVECTION OF WARMER AIR ALOFT INTO THE REGION. THIS WILL
CONTINUE RIGHT ON INTO THE OVERNIGHT HOURS AS THE ASSOCIATED SFC
COLD FRONT CREEPS IN FROM THE WEST. BY SUNRISE THURS...MODEL
TIMING ISNT BAD...SHOWING THE FRONT DRAPED ACROSS THE NWRN CORNER
OF THE CWA.
TEMPERATURES FOR TODAY ARE A LITTLE TRICKY...AS SOME MODELS
SHOWING POOLING OF MOISTURE/HIGHER DPTS IN THE SOMEWHAT USUAL
PLACES FOR OUR CWA...ROUGHLY THE NERN THIRD OR SO...WITH DPTS IN
THE LOWER 70S. THOSE HIGHER DPTS MAY KEEP TEMPS DOWN A TOUCH IN
THOSE AREAS...AND HAVE FORECAST HIGHS RIGHT AROUND 90. FURTHER
SW...THINKING THAT TEMPS WILL REACH INTO THE MID/UPPER 90S WITH
DPTS IN THE LOWER 60S. NOT BUYING INTO THE RAP WHICH IS SHOWING
LOW/MID 50S BY MID AFTERNOON DOWN THERE...WITH TEMPS THEN CLIMBING
INTO THE LOW 100S. SOMETHING FOR THE DAY SHIFT TO WATCH THOUGH. AS
WE GET INTO TONIGHT...WITH THE CONTINUED SOUTHERLY FLOW EXPECTED
THROUGH THE MAJORITY OF THE NIGHT...OVERNIGHT LOWS LOOK TO REMAIN
MILD IN THE MID 60S TO MID 70S.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 417 AM CDT WED SEP 3 2014
MAIN ISSUE WILL BE POTENTIAL FOR PRECIPITATION.
WE BEGIN THE LONG TERM ON THURSDAY UNDER UPPER LEVEL SOUTHWEST
FLOW WITH A SUBTROPICAL HIGH IN THE SOUTHEASTERN UNITED STATES.
AND A POSITIVELY TILTED TROUGH OVER THE NORTHWESTERN UNITED
STATES.
MOST IF NOT ALL OF THURSDAY SHOULD BE DRY...DESPITE A SURFACE COLD
FRONT MAKING ITS WAY SLOWLY SOUTH AS NUMERICAL MODELS CONTINUE
TO SHOW POST-FRONTAL PRECIPITATION DEVELOPING MAINLY THURSDAY
EVENING CLOSER TO THE VICINITY OF THE UPPER LEVEL JET
STREAK...WHICH WILL NUDGE SOUTH OVER TIME...AND IN TURN PUSHING
THE COLD FRONT FARTHER SOUTH.
INSTABILITY EVENTUALLY WANES AND THERE WILL BE LESS OF A
THUNDERSTORM CHANCE HEADING INTO FRIDAY AND TOOK OUT THUNDER BY
LATE EVENING FRIDAY NIGHT INTO SATURDAY.
THE FRONT IS STILL EXPECTED TO MAKE A RETURN AS THE SURFACE HIGH
THAT HELPED PUSH THE COLD FRONT SOUTH...MAKES A FAIRLY QUICK
RETREAT TO THE EAST...ALLOWING THE FRONT TO RETURN NORTH AS A
WARM FRONT.
ANOTHER COLD FRONT TUESDAY AFTERNOON/NIGHT WILL BRING IN SOME
COOLER WEATHER FOR WEDNESDAY.
THERE COULD BE ENOUGH OF A COMBINATION OF SHEAR AND INSTABILITY
FOR STRONG TO SEVERE THUNDERSTORMS ANYWHERE FROM SUNDAY NIGHT
INTO TUESDAY...BUT IT WOULD BE A TOUGH CALL TO NAIL ANYTHING DOWN
RIGHT NOW.
FOR TEMPERATURES...I WENT WITH CONSRAW FOR LOWS THURSDAY NIGHT AND
FRIDAY NIGHT. NAM FOR HIGHS THURSDAY AND BCCONSRAW FOR HIGHS
FRIDAY...WHICH ARE CONSIDERABLY COOLER. IN FACT...FRIDAY SHOULD
FEEL RATHER FALL-LIKE. OTHER NUMERICAL MODEL SOLUTIONS HAVE NOT
CAUGHT ON LIKE THE BCCONSRAW HAS...BUT I STRONGLY SUSPECT THAT
THEY WILL SOON...CONSIDERING THE TRACK RECORD OF THIS SOLUTION THE
DAY AFTER A COLD FRONT PASSAGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1229 PM CDT WED SEP 3 2014
PERSISTENT MVFR CIGS THIS MORNING ARE EXPECTED TO DISSIPATE OVER
THE NEXT FEW HOURS AS SATELLITE IMAGERY IS CONTINUING TO SHOW THIS
AREA OF CLOUD COVER SLOWLY ERODING. OTHERWISE...EXPECT MAINLY
CLEAR SKIES ONCE THE STRATUS DOES BURN OFF...WITH OCCASIONALLY
GUSTY SOUTHERLY WINDS TO 25 KTS OR SO. OVERNIGHT...EXPECT THE
POSSIBILITY OF SOME MARGINAL WIND SHEAR AS THE LOW LEVEL JET
INCREASES...AND INCLUDED THIS MENTION AT BOTH SITES AS WELL. A
STRONG COLD FRONT IS THEN EXPECTED TO CROSS THE TERMINALS BETWEEN
04/15Z-04/18Z...AND INDICATED A WIND SHIFT AHEAD OF THIS FRONT
TOWARDS THE TAIL END OF THE VALID TAF PERIOD.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...ADO
LONG TERM...HEINLEIN
AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS HASTINGS NE
639 AM CDT WED SEP 3 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 417 AM CDT WED SEP 3 2014
UPPER AIR AND SATELLITE DATA SHOWING THE AREA CONTINUING TO BE
INFLUENCED BY ZONAL FLOW...AS HIGH PRESSURE EXTENDS ACROSS THE SRN
CONUS AND BROAD TROUGHING IS IN PLACE NEAR/NORTH OF THE CANADIAN
BORDER...THOUGH AN AREA OF LOW PRESSURE IS PUSHING ITS WAY FURTHER
INLAND FROM THE PAC NW COAST. AS WAS SHOWN BY MODELS...CONVECTION
DEVELOPED EARLIER ACROSS CENTRAL KANSAS...IN RESPONSE TO A WEAK
DISTURBANCE AS WELL AS INCREASED LIFT VIA WARM AIR/MOISTURE
ADVECTION ASSOCIATED WITH A STRONGER LLJ. EARLY ON THE FAR
SOUTHEASTERN CORNER OF MITCHELL COUNTY WAS CLIPPED BY THIS
ACTIVITY...BUT SINCE THEN HAS REMAINED OVER ERN KS. THERE IS A
COUPLE ISOLATED SHOWERS OVER WESTERN KS...AND THE HRRR/RAP HINT AT
SOME ADDITIONAL ACTIVITY POSSIBLY LINGERING INTO THE MID MORNING
HOURS...SO WILL HAVE TO MONITOR HOW THIS ACTIVITY EVOLVES OVER
NEXT FEW HOURS. SATELLITE IMAGERY ALSO SHOWING SOME LOW/MID LEVEL
STRATUS STARTING TO INCREASE IN COVERAGE...BUT MODELS DIFFER SOME
ON HOW EXPANSIVE IT WILL END UP BEING. AT THE SURFACE...THE CWA IS
SET UP BETWEEN HIGH PRESSURE AFFECTING MUCH OF THE ERN CONUS...AND
A TROUGH OF LOW PRESSURE OVER THE HIGH PLAINS. WINDS REMAIN
SOUTHERLY...WITH SPEEDS RANGING FROM 5 TO 15 MPH. TEMPS ARE MORE
MILD THAN 24 HRS AGO...WITH 3 AM TEMPS IN THE MID 60S TO LOWER
70S.
THE MAIN STORY IN THE SHORT TERM PERIOD LIES WITH
TEMPERATURES...AS TODAY IS EXPECTED TO BE THE WARMEST OVER THE
NEXT 7. IN THE UPPER LEVELS...MODELS IN GOOD AGREEMENT SHOWING THE
FLOW TRANSITIONING TO MORE SOUTHWESTERLY AS THAT ABOVE MENTION PAC
NW DISTURBANCE SHIFTS FURTHER EASTWARD INTO THE NRN ROCKIES. WHILE
NOT EXPECTING MUCH IN THE WAY OF PRECIP CHANCES THROUGH TONIGHT
/THOUGH CHANCES ARE NOT ZERO/...THIS PATTERN WILL HELP TO CONTINUE
THE ADVECTION OF WARMER AIR ALOFT INTO THE REGION. THIS WILL
CONTINUE RIGHT ON INTO THE OVERNIGHT HOURS AS THE ASSOCIATED SFC
COLD FRONT CREEPS IN FROM THE WEST. BY SUNRISE THURS...MODEL
TIMING ISNT BAD...SHOWING THE FRONT DRAPED ACROSS THE NWRN CORNER
OF THE CWA.
TEMPERATURES FOR TODAY ARE A LITTLE TRICKY...AS SOME MODELS
SHOWING POOLING OF MOISTURE/HIGHER DPTS IN THE SOMEWHAT USUAL
PLACES FOR OUR CWA...ROUGHLY THE NERN THIRD OR SO...WITH DPTS IN
THE LOWER 70S. THOSE HIGHER DPTS MAY KEEP TEMPS DOWN A TOUCH IN
THOSE AREAS...AND HAVE FORECAST HIGHS RIGHT AROUND 90. FURTHER
SW...THINKING THAT TEMPS WILL REACH INTO THE MID/UPPER 90S WITH
DPTS IN THE LOWER 60S. NOT BUYING INTO THE RAP WHICH IS SHOWING
LOW/MID 50S BY MID AFTERNOON DOWN THERE...WITH TEMPS THEN CLIMBING
INTO THE LOW 100S. SOMETHING FOR THE DAY SHIFT TO WATCH THOUGH. AS
WE GET INTO TONIGHT...WITH THE CONTINUED SOUTHERLY FLOW EXPECTED
THROUGH THE MAJORITY OF THE NIGHT...OVERNIGHT LOWS LOOK TO REMAIN
MILD IN THE MID 60S TO MID 70S.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 417 AM CDT WED SEP 3 2014
MAIN ISSUE WILL BE POTENTIAL FOR PRECIPITATION.
WE BEGIN THE LONG TERM ON THURSDAY UNDER UPPER LEVEL SOUTHWEST
FLOW WITH A SUBTROPICAL HIGH IN THE SOUTHEASTERN UNITED STATES.
AND A POSITIVELY TILTED TROUGH OVER THE NORTHWESTERN UNITED
STATES.
MOST IF NOT ALL OF THURSDAY SHOULD BE DRY...DESPITE A SURFACE COLD
FRONT MAKING ITS WAY SLOWLY SOUTH AS NUMERICAL MODELS CONTINUE
TO SHOW POST-FRONTAL PRECIPITATION DEVELOPING MAINLY THURSDAY
EVENING CLOSER TO THE VICINITY OF THE UPPER LEVEL JET
STREAK...WHICH WILL NUDGE SOUTH OVER TIME...AND IN TURN PUSHING
THE COLD FRONT FARTHER SOUTH.
INSTABILITY EVENTUALLY WANES AND THERE WILL BE LESS OF A
THUNDERSTORM CHANCE HEADING INTO FRIDAY AND TOOK OUT THUNDER BY
LATE EVENING FRIDAY NIGHT INTO SATURDAY.
THE FRONT IS STILL EXPECTED TO MAKE A RETURN AS THE SURFACE HIGH
THAT HELPED PUSH THE COLD FRONT SOUTH...MAKES A FAIRLY QUICK
RETREAT TO THE EAST...ALLOWING THE FRONT TO RETURN NORTH AS A
WARM FRONT.
ANOTHER COLD FRONT TUESDAY AFTERNOON/NIGHT WILL BRING IN SOME
COOLER WEATHER FOR WEDNESDAY.
THERE COULD BE ENOUGH OF A COMBINATION OF SHEAR AND INSTABILITY
FOR STRONG TO SEVERE THUNDERSTORMS ANYWHERE FROM SUNDAY NIGHT
INTO TUESDAY...BUT IT WOULD BE A TOUGH CALL TO NAIL ANYTHING DOWN
RIGHT NOW.
FOR TEMPERATURES...I WENT WITH CONSRAW FOR LOWS THURSDAY NIGHT AND
FRIDAY NIGHT. NAM FOR HIGHS THURSDAY AND BCCONSRAW FOR HIGHS
FRIDAY...WHICH ARE CONSIDERABLY COOLER. IN FACT...FRIDAY SHOULD
FEEL RATHER FALL-LIKE. OTHER NUMERICAL MODEL SOLUTIONS HAVE NOT
CAUGHT ON LIKE THE BCCONSRAW HAS...BUT I STRONGLY SUSPECT THAT
THEY WILL SOON...CONSIDERING THE TRACK RECORD OF THIS SOLUTION THE
DAY AFTER A COLD FRONT PASSAGE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 635 AM CDT WED SEP 3 2014
MAIN FORECAST CONCERN COMES THIS MORNING...AS RESTRICTIONS WITH AT
LEAST CEILINGS SEEMS LIKELY AS AN AREA OF LOW LEVEL STRATUS
EXPANDS ACROSS THE AREA. SURROUND OBS SHOWING CEILINGS LESS THAN
1000FT...AND HAVE THOSE CONDITIONS IN AT BOTH TERMINALS THROUGH
MID MORNING...LIFTING A BIT FOR THE LATE MORNING HOURS. MODELS
SUGGEST VFR CONDITIONS ARE EXPECTED TO RETURN THIS
AFTERNOON...WILL SEE HOW THAT PANS OUT. ADJUSTMENTS TO THE TIMING
OF CEILING IMPROVEMENTS MAY BE NEEDED. ONGOING PRECIPITAITON
SLIDING IN FROM THE WEST AT THIS POINT LOOKS TO REMAIN SOUTH OF
THE TERMINAL AREAS. WINDS THROUGH THE PERIOD WILL REMAIN
SOUTHERLY...INCREASING WITH TIME...WITH SPEEDS THIS AFTERNOON IN
THE 15 TO 25 MPH RANGE...GUSTS NEAR 30 MPH POSSIBLE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...ADO
LONG TERM...HEINLEIN
AVIATION...ADO
AREA FORECAST DISCUSSION
NWS HASTINGS NE
418 AM CDT WED SEP 3 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 417 AM CDT WED SEP 3 2014
UPPER AIR AND SATELLITE DATA SHOWING THE AREA CONTINUING TO BE
INFLUENCED BY ZONAL FLOW...AS HIGH PRESSURE EXTENDS ACROSS THE SRN
CONUS AND BROAD TROUGHING IS IN PLACE NEAR/NORTH OF THE CANADIAN
BORDER...THOUGH AN AREA OF LOW PRESSURE IS PUSHING ITS WAY FURTHER
INLAND FROM THE PAC NW COAST. AS WAS SHOWN BY MODELS...CONVECTION
DEVELOPED EARLIER ACROSS CENTRAL KANSAS...IN RESPONSE TO A WEAK
DISTURBANCE AS WELL AS INCREASED LIFT VIA WARM AIR/MOISTURE
ADVECTION ASSOCIATED WITH A STRONGER LLJ. EARLY ON THE FAR
SOUTHEASTERN CORNER OF MITCHELL COUNTY WAS CLIPPED BY THIS
ACTIVITY...BUT SINCE THEN HAS REMAINED OVER ERN KS. THERE IS A
COUPLE ISOLATED SHOWERS OVER WESTERN KS...AND THE HRRR/RAP HINT AT
SOME ADDITIONAL ACTIVITY POSSIBLY LINGERING INTO THE MID MORNING
HOURS...SO WILL HAVE TO MONITOR HOW THIS ACTIVITY EVOLVES OVER
NEXT FEW HOURS. SATELLITE IMAGERY ALSO SHOWING SOME LOW/MID LEVEL
STRATUS STARTING TO INCREASE IN COVERAGE...BUT MODELS DIFFER SOME
ON HOW EXPANSIVE IT WILL END UP BEING. AT THE SURFACE...THE CWA IS
SET UP BETWEEN HIGH PRESSURE AFFECTING MUCH OF THE ERN CONUS...AND
A TROUGH OF LOW PRESSURE OVER THE HIGH PLAINS. WINDS REMAIN
SOUTHERLY...WITH SPEEDS RANGING FROM 5 TO 15 MPH. TEMPS ARE MORE
MILD THAN 24 HRS AGO...WITH 3 AM TEMPS IN THE MID 60S TO LOWER
70S.
THE MAIN STORY IN THE SHORT TERM PERIOD LIES WITH
TEMPERATURES...AS TODAY IS EXPECTED TO BE THE WARMEST OVER THE
NEXT 7. IN THE UPPER LEVELS...MODELS IN GOOD AGREEMENT SHOWING THE
FLOW TRANSITIONING TO MORE SOUTHWESTERLY AS THAT ABOVE MENTION PAC
NW DISTURBANCE SHIFTS FURTHER EASTWARD INTO THE NRN ROCKIES. WHILE
NOT EXPECTING MUCH IN THE WAY OF PRECIP CHANCES THROUGH TONIGHT
/THOUGH CHANCES ARE NOT ZERO/...THIS PATTERN WILL HELP TO CONTINUE
THE ADVECTION OF WARMER AIR ALOFT INTO THE REGION. THIS WILL
CONTINUE RIGHT ON INTO THE OVERNIGHT HOURS AS THE ASSOCIATED SFC
COLD FRONT CREEPS IN FROM THE WEST. BY SUNRISE THURS...MODEL
TIMING ISNT BAD...SHOWING THE FRONT DRAPED ACROSS THE NWRN CORNER
OF THE CWA.
TEMPERATURES FOR TODAY ARE A LITTLE TRICKY...AS SOME MODELS
SHOWING POOLING OF MOISTURE/HIGHER DPTS IN THE SOMEWHAT USUAL
PLACES FOR OUR CWA...ROUGHLY THE NERN THIRD OR SO...WITH DPTS IN
THE LOWER 70S. THOSE HIGHER DPTS MAY KEEP TEMPS DOWN A TOUCH IN
THOSE AREAS...AND HAVE FORECAST HIGHS RIGHT AROUND 90. FURTHER
SW...THINKING THAT TEMPS WILL REACH INTO THE MID/UPPER 90S WITH
DPTS IN THE LOWER 60S. NOT BUYING INTO THE RAP WHICH IS SHOWING
LOW/MID 50S BY MID AFTERNOON DOWN THERE...WITH TEMPS THEN CLIMBING
INTO THE LOW 100S. SOMETHING FOR THE DAY SHIFT TO WATCH THOUGH. AS
WE GET INTO TONIGHT...WITH THE CONTINUED SOUTHERLY FLOW EXPECTED
THROUGH THE MAJORITY OF THE NIGHT...OVERNIGHT LOWS LOOK TO REMAIN
MILD IN THE MID 60S TO MID 70S.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 417 AM CDT WED SEP 3 2014
MAIN ISSUE WILL BE POTENTIAL FOR PRECIPITATION.
WE BEGIN THE LONG TERM ON THURSDAY UNDER UPPER LEVEL SOUTHWEST
FLOW WITH A SUBTROPICAL HIGH IN THE SOUTHEASTERN UNITED STATES.
AND A POSITIVELY TILTED TROUGH OVER THE NORTHWESTERN UNITED
STATES.
MOST IF NOT ALL OF THURSDAY SHOULD BE DRY...DESPITE A SURFACE COLD
FRONT MAKING ITS WAY SLOWLY SOUTH AS NUMERICAL MODELS CONTINUE
TO SHOW POST-FRONTAL PRECIPITATION DEVELOPING MAINLY THURSDAY
EVENING CLOSER TO THE VICINITY OF THE UPPER LEVEL JET
STREAK...WHICH WILL NUDGE SOUTH OVER TIME...AND IN TURN PUSHING
THE COLD FRONT FARTHER SOUTH.
INSTABILITY EVENTUALLY WANES AND THERE WILL BE LESS OF A
THUNDERSTORM CHANCE HEADING INTO FRIDAY AND TOOK OUT THUNDER BY
LATE EVENING FRIDAY NIGHT INTO SATURDAY.
THE FRONT IS STILL EXPECTED TO MAKE A RETURN AS THE SURFACE HIGH
THAT HELPED PUSH THE COLD FRONT SOUTH...MAKES A FAIRLY QUICK
RETREAT TO THE EAST...ALLOWING THE FRONT TO RETURN NORTH AS A
WARM FRONT.
ANOTHER COLD FRONT TUESDAY AFTERNOON/NIGHT WILL BRING IN SOME
COOLER WEATHER FOR WEDNESDAY.
THERE COULD BE ENOUGH OF A COMBINATION OF SHEAR AND INSTABILITY
FOR STRONG TO SEVERE THUNDERSTORMS ANYWHERE FROM SUNDAY NIGHT
INTO TUESDAY...BUT IT WOULD BE A TOUGH CALL TO NAIL ANYTHING DOWN
RIGHT NOW.
FOR TEMPERATURES...I WENT WITH CONSRAW FOR LOWS THURSDAY NIGHT AND
FRIDAY NIGHT. NAM FOR HIGHS THURSDAY AND BCCONSRAW FOR HIGHS
FRIDAY...WHICH ARE CONSIDERABLY COOLER. IN FACT...FRIDAY SHOULD
FEEL RATHER FALL-LIKE. OTHER NUMERICAL MODEL SOLUTIONS HAVE NOT
CAUGHT ON LIKE THE BCCONSRAW HAS...BUT I STRONGLY SUSPECT THAT
THEY WILL SOON...CONSIDERING THE TRACK RECORD OF THIS SOLUTION THE
DAY AFTER A COLD FRONT PASSAGE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1224 AM CDT WED SEP 3 2014
PRIMARY CONCERN FOR THIS TAF PERIOD COMES THROUGH THE AT LEAST
MIDMORNING...WITH MODELS STILL SHOWING THE POTENTIAL FOR
FOG/STRATUS DEVELOPMENT AS MOISTURE CONTINUES TO ADVECT INTO THE
AREA FROM THE SOUTH. IF MODEL TRENDS PAN OUT...CONDITIONS SHOULD
IMPROVE AS WE GET TOWARD MIDDAY...WITH VFR CONDITIONS FOLLOWING.
NO NOTABLE CHANGES IN WINDS ARE EXPECTED...REMAINING
SOUTHERLY...THOUGH WILL BECOME MORE GUSTY THIS AFTERNOON. SPEEDS
OF 15 TO 20 MPH AND GUSTS NEAR 25 MPH ARE EXPECTED.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...ADO
LONG TERM...HEINLEIN
AVIATION...ADO
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
126 AM EDT WED SEP 3 2014
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS WILL PUSH ACROSS THE NORTH COUNTRY
THROUGH THE EVENING HOURS AHEAD OF A COLD FRONT. EXPECT LOCALLY
HEAVY DOWNPOURS AND GUSTY WINDS WITH THE STRONGER STORMS. SUNNY,
DRY AND COOLER WEATHER WILL LAST INTO THURSDAY. WARM SUMMER WEATHER
RETURNS FRIDAY BUT WILL BE SHORT LIVED AS ANOTHER COLD FRONT SWEEPS IN
EARLY SATURDAY GIVING A TASTE OF FALL-LIKE WEATHER FOR SUNDAY AND
EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
AS OF 1044 PM EDT TUESDAY...COLD FRONT CONTINUES TO MAKE ITS WAY
EASTWARD ACROSS VERMONT LATE THIS EVENING...AND WILL EXIT THE
FORECAST AREA BETWEEN 05Z-06Z. HEAVIEST PRECIPITATION WITH SOME
EMBEDDED THUNDER ALONG THE COLD FRONT...WITH POST FRONTAL RAINS
ACROSS REST OF VERMONT AND NORTHEAST NEW YORK ASSOCIATED WITH
TRAILING MID LEVEL SHORTWAVE. MAIN THREAT THIS EVENING HAS BEEN HEAVY
RAINFALL. HOWEVER...RAINFALL RATES IN HEAVIER PRECIPITATION HAVE
DECREASED ENOUGH SO THAT THREAT OF FLASH FLOODING HAS DIMINISHED.
HAVE MADE SOME MINOR ADJUSTMENTS TO FORECAST WITH LATEST UPDATE TO
ACCOUNT FOR LATEST OBSERVATIONAL DATA AND TRENDS.
EARLIER DISCUSSION...
WELL, THE ATMOSPHERE IS FAIRLY PRIMED. VERY WARM AND HUMID
AIRMASS IS RESULTING IN MODEST SURFACE BASED INSTABILITY (CAPE
PUSHING 2000 J/KG AND LIFTED INDEX OF -2 TO -4C). SO FAR THE
ACTIVITY HAS BEEN SPARSE ACROSS THE FORECAST AREA, HOWEVER RADAR
SHOWS THE BUILDING LINE OF SHOWERS AND THUNDERSTORMS OUT ACROSS
ONTARIO. THESE STORMS SHOULD BE CROSSING INTO THE UNITED STATES IN
THE NEXT COUPLE OF HOURS. STILL LIKE HOW THE HRRR AND OUR LOCAL
6KM WRF ARE HANDLING THE EVOLUTION OF THE CONVECTION. STILL LOOKS
LIKE AN ETA INTO THE CHAMPLAIN VALLEY DURING THE EVENING (LET`S GO
WITH 6-8PM) AND THEN INTO EASTERN VERMONT BY 10PM. UPPER LEVEL
SHORTWAVE WHICH IS THE PRIMARY TRIGGER FOR THE CONVECTION IS NOW
OVER MICHIGAN AND STARTING TO LIFT NORTHEAST. OUT AHEAD OF THAT
SHORT WAVE THE WIND FIELDS AND RELATED SHEAR INCREASE, BUT AT THE
SAME TIME WE ARE GETTING CLOSER TO SUNSET AND LOSS OF HEATING. SO
IT`S A BATTLE BETWEEN TIMING OF THE BEST DYNAMICS VS BEST
INSTABILITY.
AT THIS POINT STILL SEE NOTHING TO CHANGE THE IDEA THAT WE`LL HAVE
AT LEAST A FEW STRONG T-STORMS AROUND, ESPECIALLY THIS EVENING AND
MAINLY WEST OF THE GREEN MOUNTAINS. HAVE MAINTAINED THE IDEA OF
GUSTY WINDS AND HEAVY RAIN AS THE PRIMARY THREATS.
THE ACTIVITY WINDS DOWN BY MID EVENING IN THE ST LAWRENCE VALLEY
TO JUST AFTER MIDNIGHT IN EASTERN VERMONT. DEPENDING ON HOW MUCH
CLEARING WE GET, WE COULD HAVE A BIT OF PATCHY FOG LATE TONIGHT.
THE COOLER AIR LAGS THE WEATHER A BIT, SO IT WILL STILL BE A MUGGY
NIGHT WITH LOWS IN THE 60S.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH THURSDAY NIGHT/...
AS OF 355 PM EDT TUESDAY...IT WILL BE A QUIET 48 HOURS. SHORT TERM
MODELS IN PRETTY GOOD AGREEMENT WITH REGARD TO RIDGING OVER THE REGION.
DAILY SPECIFICS...
WEDNESDAY: FLOW TURNS NORTHWEST DURING THE MORNING. 850MB
TEMPERATURES FALL TO 11-12C WHICH WILL SUPPORT HIGH TEMPERATURES
IN THE MID-UPPER 70S. WITH SOME WEAK COLD-AIR ADVECTION AND A GOOD
DEAL OF SUN, WE`LL HAVE SOME EXCELLENT MIXING DURING THE
AFTERNOON. WE SHOULD BE ABLE TO TAP SOME OF THE 20KT OR SO OF WIND
THAT WILL BE A FEW THOUSAND FEET UP, SO IT SHOULD GET A LITTLE
BREEZY IN THE AFTERNOON.
WEDNESDAY NIGHT: HIGH PRESSURE OVERHEAD. CLEAR AND CALM, SO PATCHY
FOG LOOKS LIKE A GOOD BET, ESPECIALLY SINCE THE GROUND WILL STILL
BE A BIT DAMP FROM THE RAIN THIS EVENING. TEMPERATURES MAINLY IN
THE 50S, THOUGH UPPER 40S POSSIBLE IN COLD SPOTS LIKE SARANAC LAKE.
THURSDAY: SHORTWAVE RIDGING AND SURFACE HIGH PRESSURE STILL NEARLY
OVERHEAD, BUT STARTING TO PUSH EAST OF THE AREA. 850MB
TEMPERATURES UP TO 12-13C, WHICH SUPPORTS UPPER 70S TO LOW 80S FOR
HIGHS. PLENTY OF SUN AS WELL.
THURSDAY NIGHT: DISCARDED THE NAM AS IT SEEMS TOO AGRESSIVE WITH
THE LEADING EDGE OF WARM AIR ADVECTION AND PRODUCES THICKENING
CLOUDS AND EVEN SOME LIGHT SHOWERS. THINK IT WILL REMAIN MOSTLY
CLEAR AND DRY PER OTHER MODELS. HOWEVER WITH SOUTHWEST FLOW
DEVELOPING, IT WON`T BE AS COLD, LOTS OF 50S AND EVEN LOW 60S FOR
LOWS.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 350 PM EDT TUESDAY...EXTENDED PERIOD REMAINS PREDOMINATELY
QUIET...LARGELY DOMINATED BY HIGH PRESSURE STARTING THE LATTER
PART OF THE WEEKEND...BUT WET TO BEGIN. FOR THE START OF THE
PERIOD...RISING HEIGHTS AND WARMING TEMPERATURES CONTINUE FRIDAY
AS AN UPPER RIDGE CRESTS OVER THE NORTHEAST IN ADVANCE OF OUR NEXT
SURFACE FRONT. MEAN 925MB TEMPS OF +20-23C WILL SUPPORT HIGHS WELL
ABOVE NORMAL FOR EARLY SEPTEMBER WITH WIDESPREAD 80`S EXPECTED.
IT`LL BE MUGGY TOO WITH DEWPOINTS RANGING THROUGH THE 60S WHICH
WILL CREATE AMPLE SURFACE INSTABILITY TO SUPPORT SHOWER AND
THUNDERSTORM DEVELOPMENT ALONG/AHEAD OF THE AFOREMENTIONED FRONT
WHICH WILL SHIFT INTO THE BTV CWA LATE IN THE DAY AND THROUGH THE
EVENING. STILL LOOKS LIKE THE BEST UPPER DYNAMICS PASSES TO OUR
NORTH...WITH THE SURFACE BOUNDARY PARALLEL WITH UPPER FLOW
SUPPORTING THE IDEA OF A SLOW EASTWARD PROGRESSION WHICH IS
MAINTAINED BY THE LATEST ECMWF. GFS REMAINS A BIT FASTER PUSHING
THE BOUNDARY THROUGH THE CWA BY SATURDAY MORNING SO HAVE CONTINUED
ON WITH THE PREVIOUS FORECAST THINKING LEANING TOWARDS THE ECMWF.
BY LATE SATURDAY TREND WILL BE TOWARDS CLEARER AND DRIER WEATHER AS
THE UPPER FLOW TURNS ZONAL AND SURFACE HIGH PRESSURE BUILDS
EASTWARD OUT OF THE CENTRAL CONUS. THIS HIGH THEN SLOWLY SHIFTS EAST
THROUGH THE NORTHEAST AND OFF INTO THE CANADIAN MARITIMES BY LATE
TUESDAY OFFERING A NICE STRETCH OF LATE SUMMER WEATHER. TEMPS RETURN
TO MORE SEASONABLE LEVELS TO MAYBE SLIGHTLY BELOW NORMAL WITH
EXPECTED HIGHS SATURDAY THROUGH TUESDAY IN THE UPPER 60S TO LOW
70S...AND LOWS IN THE MID 40S TO LOW 50S.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
THROUGH 06Z THURSDAY...BULK OF THE RAINFALL HAS MOVED EAST OUT OF
VERMONT AND ALL TAF SITES FORECASTS ARE RAIN FREE. LIFR CEILINGS
AT KMSS KSLK KMPV EXPECTED TO CONTINUE OVERNIGHT. VFR CIGS ELSEWHERE
THROUGH 12Z THEN CONDITIONS IMPROVE TO VFR CLR. QUITE A BIT OF
VARIABILITY WITH CLOUD COVER ACROSS THE AREA...AND EXPECT TO BE
CHASING OBS WITH AMENDMENTS THROUGH MORNING HOURS AS CIGS VARY UP
AND DOWN IN THE LIFR LOCATIONS. DID NOT HIT VIS TOO HARD DESPITE
OVERNIGHT RAINFALL...THINKING CLOUD COVER WILL INHIBIT RADIATIONAL
COOLING AND FOG FORMATION. LIGHT WEST TO NW WIND THROUGH THE
FORECAST PERIOD.
OUTLOOK 00Z THURSDAY THROUGH SUNDAY...
06Z THU - 00Z SAT...VFR UNDER HIGH PRESSURE. EARLY MORNING IFR
FOG POSSIBLE...ESPECIALLY AT KMPV/KSLK.
00Z SAT - 00Z SUN...POSSIBLE MVFR AND BRIEF IFR IN SCATTERED SHOWERS
AND THUNDERSTORMS.
00Z SUN - 00Z MON...VFR UNDER HIGH PRESSURE. EARLY MORNING IFR FOG
POSSIBLE...ESPECIALLY AT KMPV/KSLK.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...NASH
NEAR TERM...RJS/NASH
SHORT TERM...NASH
LONG TERM...LAHIFF
AVIATION...HANSON
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1127 PM EDT THU SEP 4 2014
.SYNOPSIS...
SUMMERTIME WEATHER WILL CONTINUE INTO THE WEEKEND. AN APPROACHING
COLD FRONT WILL BRING AN INCREASING CHANCE OF THUNDERSTORMS LATER
IN THE WEEKEND. HIGH PRESSURE BUILDING FROM THE NORTH WILL BRING
SLIGHT COOLING AND SEASONABLE TEMPERATURES EARLY NEXT WEEK. A
STRONGER COLD FRONT MAY APPROACH THE COAST BY THE MIDDLE OF NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS OF 1045 PM THURSDAY...PCPN TREND FROM THE PREVIOUS UPDATE
STILL HOLDS. HAVE TEMPORARILY ENDED PCPN OVER LAND AREAS ACROSS
THE ILM CWA. BUT WILL CONTINUE THE INCREASING DEVELOPMENT OF
NOCTURNAL SHRA/TSRA ACROSS THE ADJACENT ATL WATERS DURING THE PRE-
DAWN FRI HRS VIA LATEST HRRR MODEL OUTPUT. THE EVENTUAL ONSHORE
MOVEMENT OF THIS PCPN WILL OCCUR TOWARD DAYBREAK FRI...AND THUS
WILL MAINTAIN ATLEAST A 20 POP FOR THE COASTAL COUNTIES AND EXTEND
FURTHER INLAND AFTER SUNRISE FRI. NO TWEAKS TO OVERNITE TEMPS/DEWPTS
AT THIS TIME.
PREVIOUS DISCUSSION.............................................
AS OF 715 PM THURSDAY...LATEST KLTX 88D AND SURROUNDING 88DS
INDICATE THE DIURNALLY DRIVEN CONVECTION HAS ENDED ACROSS THE ILM
CWA. AS A RESULT...HAVE REMOVED POPS FOR THE REMAINDER OF THIS
EVENING AND INTO THE PRE-DAWN FRI HRS. IN ADDITION HAVE DECREASED
CLOUD COVERAGE GIVEN LATEST SAT IMAGERY...AND WITH CONVECTIVE
DEBRIS CLOUDS REMAINING WELL UPSTREAM. HOWEVER...HAVE RAMPED UP
THE NOCTURNAL SHRA/TSRA POP ALONG THE COASTAL COUNTIES FROM PCPN MOVING
ONSHORE FROM OFF THE ATL OCEAN TO ATLEAST 20...AND POSSIBLY UP TO
30 LEADING UP TO FRI SUNRISE AND IMMEDIATELY THERE-AFTER. VARIOUS
MODEL TIME HEIGHT DISPLAYS ACROSS COASTAL NC-SC INDICATE A MUCH
DEEPER ONSHORE FLOW...IE. SE-SSW FLOW UP TO 5H...ACROSS COASTAL
NC-SC...AND ALSO ALONG WITH PLENTY OF LOW-LEVEL MOISTURE AFTER
MIDNIGHT FRI...EXTENDING FROM THE SFC UP THRU 8H. ONSHORE FLOW
HAVING CROSSED SSTS AROUND 80 DEGREES...WILL KEEP TONIGHTS LOWS
IN THE MID AND UPPER 70S AT THE COAST. LOWER 70S LIKELY FAR WEST
PORTIONS...MAINLY ALONG AND WEST OF THE I-95 CORRIDOR.
PREVIOUS DISCUSSION..................................
AS OF 130 PM THURSDAY...FORECAST FOR THE AFTERNOON AND OVERNIGHT
HOURS REMAINS RELATIVELY UNCHANGED. ALL WE HAVE SEEN SO FAR IS
VERY SHALLOW TROPICAL SHOWERS AND THE CUMULUS FIELD LOOKS LIKE
THIS CWA WIDE SO THE CHANCE OF DEEP CONVECTION IS DIMINISHING.
STILL CANT RULE OUT SOME DEEPER ACTIVITY ACROSS NORTHWESTERN AREAS
AND WILL ADJUST POPS ACCORDINGLY IF NECESSARY. WILL MAINTAIN THE
LOW CHANCE POPS FOR THE AFTERNOON HOURS AND FOR THE ACTIVITY
EXPECTED TO DEVELOP ACROSS THE ATLANTIC OVERNIGHT. OVERNIGHT LOWS
REMAIN STEAMY AND OPTED FOR THE WARMER GUIDANCE WHICH HAS BEEN A
GOOD PLAY RECENTLY.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
AS OF 3 PM THURSDAY...HAVE FAVORED THE SLOWER GFS SOLUTION FOR
THIS PERIOD OVER THE MORE PROGRESSIVE NAM. HIGH PRESSURE CONTINUES
ACROSS THE SOUTHEAST AS THE DOMINATE WEATHER MAKER...WEAK SURFACE
FLOW WILL ALLOW SEA BREEZE TO PUSH INLAND AND THIS WILL SERVE AS
THE MAIN TRIGGER ELEMENT FOR ANY SHOWERS OR STORMS THAT DEVELOP
THROUGHOUT THE AFTERNOON. HAVE FAVORED THE LOWER CHANCE POPS OF
THE GFS AS NAM RAMPS UP POPS I THINK TOO QUICKLY BY LATE DAY IN THE
ABSENCE OF ANY UPPER LEVEL DISTURBANCE THAT REMAINS WELL TO THE
WEST OF THE CWA BY FRIDAY LATE AFTERNOON. APPROACHING FRONTAL
BOUNDARY WILL REMAIN WELL TO OUR WEST AND NORTHWEST FRIDAY. WITH
LESS CLOUD COVER ON THE GFS THAN NAM FAVORED THE HIGHER GFS TEMPS
OF UPPER 80S TO AROUND 90 INLAND WITH H8 TEMPS AROUND 18C WITH A
WEAK LESS THAN 10 KT SOUTHERLY H8 FLOW INCREASING MOISTURE INTO
THE REGION. ON SATURDAY I START TO RAMP UP THE POPS BY THE END OF
THE PERIOD AS COMBINATION OF INCREASED SOUTHERLY H8 SPEED
CONVERGENCE INTERACTS WITH SEA BREEZE FRONT TO IGNITE MORE
SCATTERED SHOWERS AND STORMS ESPECIALLY LATER IN THE AFTERNOON.
WEAK H5 DISTURBANCE MOVES INTO THE WESTERN PORTION OF THE STATE
AND SHOULD ENHANCE THE PIEDMONT TROUGH CONVECTION DURING SATURDAY
EVENING SO WILL UP THE POPS HERE LATE IN THE PERIOD. WITH A JUICY
ATMOSPHERE ANY SHOWERS OR STORMS WILL HAVE THE POTENTIAL TO
PRODUCE SOME LOCALLY HEAVY RAINS ESPECIALLY INLAND AS THE STEERING
WINDS WILL BE LIGHTER COMPARED TO NEAR THE COAST WHERE THE LOW
LEVEL JET SHOULD HAVE A 190 DIRECTION AT AROUND 15 KNOTS WHICH
SHOULD HELP IN KEEPING ANY PROLONG PERIOD OF RAIN OVER ANY AREA.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 3 PM THURSDAY...THE SUBTROPICAL RIDGE WILL REMAIN TO OUR
SOUTH NEXT WEEK WITH THE SOUTHERN EDGE OF THE MID-LATITUDE
WESTERLIES BRUSHING THE CAROLINAS. MODELS SHOW THE BEST POTENTIAL
FOR DEEP MOISTURE AND CYCLONIC CURVATURE TO THE 500 MB FLOW WILL
BE SUNDAY/MONDAY...COINCIDENT WITH THE ARRIVAL OF A COLD FRONT
PUSHED SOUTHWARD INTO THE CAROLINAS BY SURFACE HIGH PRESSURE OVER
THE UPPER MIDWEST. AS WEAK LOW PRESSURE DEVELOPS ALONG THE STALLED
FRONT OVER SOUTHERN SOUTH CAROLINA/EASTERN GEORGIA MONDAY...MOIST
SOUTHEAST WINDS WILL ADVECT PLENTY OF ATLANTIC MOISTURE ONSHORE
ACROSS THE AREA. THIS COULD LEAD TO FAIRLY WIDESPREAD SHOWERS AND
T-STORMS. I HAVE INCREASED FORECAST POPS TO 50-70 PERCENT SUNDAY
AND MONDAY.
ONE INTERESTING FEATURE THAT WILL HAVE TO BE WATCHED CLOSELY IS
LOCATED OFF THE FLORIDA EAST COAST THIS AFTERNOON. MODELS SHOW SOME
OF THE DEEP TROPICAL MOISTURE TRAILING BEHIND THIS CYCLONIC SWIRL
COULD BE INGESTED INTO THE SUNDAY/MONDAY WEATHER SYSTEM. WHILE THIS
NOT GOING TO BE A TROPICAL SYSTEM PER SE...ADVECTING TROPICAL
MOISTURE ACROSS A SYNOPTIC COLD FRONT CAN LEAD TO SIGNIFICANT AND
PERHAPS EXCESSIVE RAINFALL.
THE WEAK SURFACE LOW SHOULD LIFT OUT TO THE NORTHEAST TUESDAY WITH
RAINFALL CHANCES DIMINISHING THROUGH MID-WEEK. THE AIRMASS WILL
REMAIN TROPICAL AND MAINLY DIURNAL 20-30 POPS WILL REMAIN IN THE
FORECAST.
HIGH TEMPERATURES WILL REMAIN BELOW CLIMATOLOGICAL NORMS MONDAY AND
TUESDAY DUE TO THE CLOUDS AND PRECIP ANTICIPATED WITH THE FRONT
STALLING NEAR THE AREA. ONCE THIS FEATURE IS GONE TUESDAY HIGH
TEMPERATURES SHOULD REMAIN TO NEAR OR EVEN SLIGHTLY ABOVE NORMALS
FOR THE REST OF THE WEEK.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
AS OF 00Z...POTENTIAL FOR MVFR/IFR DUE TO FOG LATE OVERNIGHT/EARLY
MORNING HOURS. OTHERWISE EXPECT VFR WITH A CHANCE OF AFTERNOON
SHRA/TSRA ON THURSDAY.
VFR PREVAILS THIS EVENING WITH LINGERING CLOUDS AND SOUTH-SOUTHEAST
WINDS AOB 10 KTS. EXPECT THE WINDS TO DECREASE IN SPEED OVER THE
NEXT FEW HOURS. THERE IS THE POTENTIAL FOR MVFR/POSSIBLE IFR DUE TO
AREAS OF FOG/LOW CIGS AT THE INLAND SITES LATE OVERNIGHT INTO THE
EARLY MORNING HOURS. DO NOT ANTICIPATE ANY OF THIS TO DEVELOP ALONG
THE COAST IN THE MORNING HOURS...BUT COULD SEE SOME ISOLATED SHOWERS.
ON FRIDAY...VFR WILL PREVAIL WITH SOUTH-SOUTHEAST WINDS AROUND 5 TO
10 KITS...SLIGHTLY HIGHER ALONG THE COAST...WITH A CHANCE OF
SHRA/TSRA.
EXTENDED OUTLOOK...PATCHY MVFR/IFR FOG OR STRATUS MAY DEVELOP EACH
MORNING. A COLD FRONT DROPS INTO THE REGION SUNDAY AND MONDAY...WITH
A GOOD CHANCE FOR SHOWERS AND STORMS BOTH DAYS. THE FRONT STALLS
WITH A CONTINUED CHANCE FOR SHOWERS TUESDAY AND WEDNESDAY.
&&
.MARINE...
NEAR TERM/THROUGH TONIGHT/...
AS OF 1100 PM THURSDAY...NEARLY A PCPN FREE COASTAL AND
ADJACENT OFFSHORE WATERS AT THE MOMENT...VIA LATEST KLTX 88D
AND SURROUNDING RADARS. STILL BANKING ON THE LATEST HRRR WHICH
INDICATES PCPN RE-FIRING DURING THE PRE-DAWN FRI HRS. NO POP
CHANGES NEEDED AT THIS TIME. LATEST BUOYS OBS ACROSS AND IN THE
NEIGHBORHOOD OF THE ILM COASTAL WATERS CONTINUE TO SUPPORT THE
PREVIOUS UPDATE WITH VERY LITTLE TWEAKING...IF ANY...NEEDED TO
EITHER WINDS/SEAS IN THIS UPDATE.
PREVIOUS DISCUSSION..............................................
AS OF 730 PM THURSDAY...LATEST PROGGED SFC PRESSURE PATTERN AND
RELAXED GRADIENT ACROSS THE ILM WATERS OVERNIGHT TO YIELD A SE-S
WIND AT 10 TO 15 KT...WITH THE 15 KT BEING VERY GENEROUS.
SIGNIFICANT SEAS WILL REMAIN IN A 2 TO 3 FOOT RANGE...WITH THE
DOMINANT PLAYER WITH THE SIG. SEAS BEING A LAZY 2 FOOT ESE GROUND
SWELL EXHIBITING 8 SECOND PERIODS. THE REMAINDER OF THE SIG. SEAS
PRODUCTION WILL COME FROM A 1-2 FOOT LOCALLY PRODUCED WIND WAVE AT
4-5 SECOND PERIODS. NOCTURNAL SHRA/TSRA WILL INCREASE IN COVERAGE
ACROSS THE LOCAL WATERS DURING THE MID TO LATE PRE-DAWN FRI HRS.
PREVIOUS DISCUSSION...........................................
AS OF 130 PM THURSDAY...MUCH LIKE THE PUBLIC PART OF THE
FORECAST...THE COASTAL WATERS FORECAST REMAINS STABLE. SOUTH WINDS
HOVERING AROUND TEN KNOTS WILL CONTINUE. SIGNIFICANT SEAS WILL BE
1-3 FEET WITH MOSTLY LOCAL WIND DRIVEN WAVES WITH PERIODS OF SIX
TO EIGHT SECONDS.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 3 PM THURSDAY...HIGH PRESSURE WILL COVER THE COASTAL
WATERS THROUGHOUT THE PERIOD. WINDS WILL GENERALLY BE LIGHT
ACROSS THE WATERS FROM THE S TO SE BUT SHOULD START TO INCREASE BY
AFTERNOON AND EVENING ON SATURDAY AS H8 WINDS DEVELOP THE LOW
LEVEL JET. SEAS WILL GENERALLY RUN AROUND A FOOT OR SO NEAR SHORE
AND 2-3 OFFSHORE. EXPECT SOME SCATTERED SHOWERS STORMS EACH DAY
WITH CONDITIONS STARTING TO DETERIORATE MORE BY THE END OF THE
PERIOD AS A COLD FRONT APPROACHES FROM THE WEST AND LOW PRESSURE
IS FORECAST TO DEVELOP ALONG THIS FRONT FOR THE LONG TERM PERIOD.
LONG TERM /SUNDAY THROUGH MONDAY/...
AS OF 3 PM THURSDAY...1022 MB HIGH PRESSURE OVER THE UPPER
MIDWEST SUNDAY WILL PUSH A COLD FRONT SOUTHWARD ACROSS THE MID-
ATLANTIC REGION. THIS FRONT SHOULD REACH THE INLAND CAROLINAS
DURING THE DAY SUNDAY BUT WILL HAVE TROUBLE PUSHING OUT ACROSS THE
COASTAL WATERS. THE LATEST SUITE OF COMPUTER MODEL DATA SHOWS THE
FRONT SHOULD REMAIN INLAND WITH SOUTH WINDS VEERING MORE
SOUTHEASTERLY MONDAY. LOW PRESSURE WILL FORM ALONG THE INLAND
PORTION OF THE FRONT ACROSS EASTERN GEORGIA/SOUTHERN SOUTH
CAROLINA MONDAY...AND AS THIS LOW PUSHES NORTHEASTWARD IT SHOULD
VEER WINDS MORE SOUTHWESTERLY TUESDAY. OUTSIDE OF THUNDERSTORMS
WIND SPEEDS SHOULD REMAIN LESS THAN 15 KNOTS THROUGH THE
PERIOD...STRONGEST SUNDAY NIGHT INTO MONDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SHK/MAC
NEAR TERM...DCH/SHK
SHORT TERM...MAC
LONG TERM...TRA
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
125 PM EDT WED SEP 3 2014
.SYNOPSIS...A SURFACE TROUGH WILL BE LOCATED OVER CENTRAL NORTH
CAROLINA THIS AFTERNOON AS A COLD FRONT REMAINS JUST TO OUR NORTH.
HIGH PRESSURE WILL BUILD BACK OVER THE AREA FOR THE REMAINDER OF THE
WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1055 AM WEDNESDAY...
THE LATEST SURFACE ANALYSIS SHOWED A SURFACE FRONT OVER NORTHERN
VIRGINIA WITH SURFACE TROUGHS CLOSE TO THE VIRGINIA BORDER EXTENDING
WEST TO EAST...AND OVER THE WESTERN PART OF CENTRAL NORTH CAROLINA.
WIND SHEAR WAS WEAK AND SHOULD REMAIN SO THROUGH THE REST OF THE
DAY...WITH RAP FORECAST 0-3KM VALUES ON THE ORDER OF 10KT OR LESS.
THE LATEST SPC MESOANALYSIS SHOWED GOOD CIN OVER THE WESTERN
PIEDMONT WITH INSTABILITY...TO 2000J/KG...ALONG THE IMMEDIATE COAST.
THE RAP FORECASTS THIS CIN...ASSOCIATED WITH A LOW-LEVEL CAP AND
GOOD DEW POINT SPREADS SUCH AS NOTED ON THE 12Z KGSO SOUNDING...
ERODING THIS AFTERNOON AROUND 20Z. WHILE IN THE MID-LEVELS THERE
SHOULD BE A WEAK SHEAR AXIS AND VORTICITY CLOSER TO THE VIRGINIA
BORDER THIS AFTERNOON...BETTER LOW-LEVEL FORCING IS EXPECTED IN
SURFACE TROUGHINESS CLOSER TO THE COASTAL PLAIN WHERE THE
INSTABILITY SHOULD ALSO BE GREATER...ON THE ORDER OF 1500J/KG THIS
AFTERNOON BASED ON RAP SOUNDINGS. THE RAP FORECASTS THE BETTER LIFT
IN THAT AREA AS WELL...GRADUALLY PROPAGATING WEST IN THE LIGHT WINDS
AND WEAK SHEAR. THE VARIETIES OF HRRR WRF GUIDANCE LEAN TOWARD
INITIAL DEEP CONVECTIVE DEVELOPMENT TOWARD INTERSTATE 95 GRADUALLY
PROPAGATING NORTHWEST...STRUGGLING TO MAKE IT INTO THE TRIAD WHERE
OVERALL STABILITY SHOULD BE GREATER. FOR THE MORNING UPDATE...
DELAYED THE ONSET OF ISOLATED TO SCATTERED POPS AND TRENDED ANY TO
LATE IN THE DAY AND INTO THIS EVENING OVER THE NORTHWEST PIEDMONT.
GIVEN DCAPE FORECAST AT A MAXIMUM AROUND 700J/KG THIS AFTERNOON...
AN ISOLATED STORM COULD PRODUCE A STRONG WIND GUST...BUT INSTANCES
OF SUCH SHOULD BE PULSE-LIKE IN WEAK SHEAR AND WEAK WINDS ALOFT.
WITH GOOD SUN THROUGH THE MORNING AND A FAST RISE TO TEMPERATURES...
IN SEVERAL LOCATIONS RAISED MAXES A DEGREE OR TWO...FOR HIGHS OF 90
TO 95. APPARENT TEMPERATURES...LIKE IN THE HWO...SHOULD BE WITHIN
A DEGREE OR TWO OF 100 EAST OF ABOUT U.S. 1.
CONVECTIVE OVERTURNING AND NOCTURNAL STABILIZATION SHOULD REDUCE THE
COVERAGE OF SHOWERS AND STORMS OVERNIGHT...BUT GUIDANCE CONTINUES TO
SUGGEST THERE MAY BE A FEW CELLS AROUND. LOWS WILL BE IN THE UPPER
60S AND LOWER 70S.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
AS OF 305 AM WEDNESDAY...
THE BERMUDA HIGH BUILDS BACK ACROSS THE REGION ON THURSDAY...WITH A
SOUTHERLY WIND DEVELOPING ACROSS THE AREA. MOISTURE CONTENT REMAINS
HIGH WITH PW NEAR 2 INCHES AND MODERATE INSTABILITY AGAIN IN THE
AFTERNOON. WITHOUT A PRE-EXISTING TROUGH/BOUNDARY...CONVECTION
SHOULD BE A LITTLE MORE FOCUSED ALONG THE HIGHER TERRAIN AND/OR
SEABREEZE...THOUGH BOTH THE GFS AND ECMWF SUGGEST AT LEAST SCATTERED
COVERAGE ACROSS CENTRAL THURSDAY AFTERNOON. H85 TEMPS AND LOW-LEVEL
THICKNESSES ARE RELATIVELY UNCHANGED FROM WEDNESDAY...THOUGH
NAM/ECMWF STATISTICAL GUIDANCE ARE A COUPLE DEGREES COOLER. WILL
INDICATE HIGHS AGAIN MOSTLY IN THE LOWER 90S. LOWS THURSDAY NIGHT IN
THE UPPER 60S AND LOWER 70S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 330 AM WEDNESDAY...
THE SUB-TROPICAL RIDGE WILL BRIEFLY EXPAND NORTH INTO THE OH VALLEY
AND MIDDLE ATLANTIC...AND CONSEQUENTLY CAUSE THE MID LEVEL SHEAR AND
MOIST AXIS SETTLING INTO CENTRAL NC THIS MORNING...TO WEAKEN AND BOW
NORTH INTO VA FRI-SAT. MEDIUM RANGE ENSEMBLE GUIDANCE SUGGESTS THE
SUB-TROPICAL RIDGE WILL THEN WEAKEN AND BECOME SUPPRESSED...BY A
PAIR OF SHORTWAVE TROUGHS FORECAST TO CROSS THE NE US AND SE CANADA
IN PROGRESSIVE FLOW ALOFT THROUGH THE END OF THE WEEKEND. GUIDANCE
IS ALSO IN AGREEMENT THAT SOME DEGREE OF TROUGHING WILL BE LEFT
BEHIND IN A POSITIVE TILT FASHION OVER THE MIDDLE ATLANTIC...THOUGH
THE DEGREE OF WHICH REMAINS UNCERTAIN DUE TO ABOVE AVERAGE MODEL
SPREAD OF THE H5 PATTERN BY DAYS 6-7 (MON-TUE). THE EBB AND FLOW OF
THE PATTERN ALOFT...AND ASSOCIATED SUPPRESSION OF THE SUB-TROPICAL
RIDGE...WILL ALLOW THE POLAR FRONT TO SETTLE SE THROUGH CENTRAL NC
CENTERED AROUND THE DAY SUNDAY...BEFORE SLOWING AS IT DRIFTS
OFFSHORE AND INTO THE VICINITY OF THE GULF STREAM THROUGH MID-WEEK.
A WEAK WAVE OF LOW PRESSURE...OR TWO...ARE APT TO DEVELOP ALONG THE
SLOWING FRONT...AS THE AFOREMENTIONED POSITIVELY TILTED TROUGH ALOFT
INTERACTS WITH SEASONABLY STRONG BAROCLINICITY DRIVEN BY THE
INCOMING COOL/DRY CANADIAN AIR MASS INTO THE WARM/MOIST GULF STREAM
WATERS.
FRI-SAT: A PATTERN OF WEAK SYNOPTIC-SCALE ASCENT AHEAD OF THE
AFOREMENTIONED POLAR FRONT WILL FAVOR NEAR CLIMO PROBABILITIES OF
DIURNALLY-DRIVEN CONVECTION ALONG THE SEA BREEZE AND MOUNTAINS...
BOTH OF WHICH WILL BE APT TO PROPAGATE INTO THE WESTERN AND EASTERN
EDGES OF THE RAH CWFA EACH AFTERNOON AND EVENING. THE DISSIPATION
AND NORTHWARD DEPARTURE OF MID-HIGH CLOUDINESS ASSOCIATED WITH THE
AFOREMENTIONED SHEAR AXIS ALOFT...RESULTING FROM THE BRIEFLY
BUILDING SUB-TROPICAL RIDGE...SHOULD ALLOW FULL-SUN (OR NEARLY SO)
H85 TEMPS IN THE 17-18C RANGE TO BE REALIZED...SUPPORTIVE OF HIGHS
OF 88 TO 93 DEGREES. SAT NIGHT-SUN: THE BEST CHANCE OF SHOWERS AND
STORMS DURING THE LONG TERM PERIOD WILL UNDOUBTEDLY ACCOMPANY THE
ARRIVAL/PASSAGE OF THE POLAR FRONT...ONE WHOSE LOW LEVEL FRONTAL
CIRCULATION WILL BE SUPPORTED THROUGH THE MID-UPPER LEVELS BY
PERSISTENT RIGHT ENTRANCE REGION UPPER JET FORCING. THE COMBINATION
OF INCREASING MID-HIGH CLOUDS AND NUMEROUS TO WIDESPREAD SHOWERS AND
STORMS SHOULD HOLD TEMPERATURES GENERALLY IN THE LOWER TO MIDDLE
80S.
SUN NIGHT-MON NIGHT: SUBSIDENCE DRYING AND LESSENING PROBABILITIES
OF RAIN WILL DEVELOP FROM NW TO SE...BUT NORTHEASTERLY LOW-MID LEVEL
FLOW ON THE WEST SIDE OF THE FRONTAL ZONE AND PROBABLE WAVES OF LOW
PRESSURE WILL RESULT IN MOSTLY CLOUDY CONDITIONS AND A CHANCE OF
RAIN OVER THE EASTERN CWFA...RANGING TO PARTIAL SUNSHINE AND
GENERALLY DRY CONDITIONS OVER THE WESTERN PIEDMONT. COOLER WITH
HIGHS IN THE UPPER 70S TO LOWER 80S.
TUE: SFC WAVES DEPART WITH LESSENING INFLUENCE OF THE NORTHEASTERLY
FLOW...AND INCREASING AMOUNTS OF SUNSHINE. MILD WITH HIGHS AGAIN IN
THE UPPER 70S TO LOWER OR PERHAPS MIDDLE 80S.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 125 PM WEDNESDAY...
A MODERATELY MOIST AND UNSTABLE AIR MASS WILL SUPPORT THE
DEVELOPMENT OF SCATTERED CONVECTION LATE THIS AFTERNOON THROUGH THIS
EVENING. THE CONVECTION WILL MOST LIKELY DEVELOP INITIALLY IN THE
VICINITY OF KFAY AND KGSB. OUTFLOWS FROM THIS AREA OF CONVECTION
WILL TRIGGER ADDITIONAL CONVECTION IN THE VICINITY OF KRWI AND KRDU
PRIOR TO SUNSET. ISOLATED TO SCATTERED CONVECTION MAY ALSO OCCUR IN
VICINITY OF KINT AND KGSO BY THIS EVENING. EXPECT BRIEF INSTANCES OF
MVFR/IFR CEILING AND VISIBILITIES IN PROXIMITY OF THE STORMS. AN
ISOLATED WIND GUSTS NEAR 40KTS MAY ALSO OCCUR.
BULK OF CONVECTION WILL DIMINISH BEFORE MIDNIGHT. EXPECT AREAS OF
MVFR/IFR CEILINGS TO DEVELOP PRIOR TO SUNRISE WITH THE NEAR TERM
MODELS FAVORING THE PIEDMONT/KINT-KGSO-KRDU TERMINALS WITH THE
GREATEST LIKELIHOOD OF ADVERSE AVIATION WEATHER CONDITIONS. MVFR
CEILINGS APPEAR TO BE A GOOD PROBABILITY FOR MOST SITES EARLY
THURSDAY MORNING WITH CEILINGS LIFTING INTO THE LOW END VFR CATEGORY
BY 16Z.
ANOTHER ROUND OF SCATTERED THUNDERSTORMS IS EXPECTED THURSDAY
AFTERNOON WITH THE GREATEST PROBABILITY OVER THE NORTHERN PIEDMONT
INCLUDING KGSO...KINT AND KRDU.
EXPECT MAINLY VFR CONDITIONS FRIDAY AND SATURDAY WITH A PERIOD OF
EARLY MORNING LOW CLOUDS AND FOG ANTICIPATED EACH DAY....AND
ISOLATED CONVECTION EACH AFTERNOON.
AN APPROACHING COLD FRONT WILL INCREASE THE THREAT FOR SCATTERED
SHOWERS AND THUNDERSTORMS SUNDAY AND MONDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...DJF/BLS
SHORT TERM...BLS
LONG TERM...MWS
AVIATION...WSS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1055 AM EDT WED SEP 3 2014
.SYNOPSIS...A SURFACE TROUGH WILL BE LOCATED OVER CENTRAL NORTH
CAROLINA THIS AFTERNOON AS A COLD FRONT REMAINS JUST TO OUR NORTH.
HIGH PRESSURE THEN WILL BUILD BACK OVER THE AREA FOR THE REMAINDER
OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1055 AM WEDNESDAY...
THE LATEST SURFACE ANALYSIS SHOWED A SURFACE FRONT OVER NORTHERN
VIRGINIA WITH SURFACE TROUGHS CLOSE TO THE VIRGINIA BORDER EXTENDING
WEST TO EAST...AND OVER THE WESTERN PART OF CENTRAL NORTH CAROLINA.
WIND SHEAR WAS WEAK AND SHOULD REMAIN SO THROUGH THE REST OF THE
DAY...WITH RAP FORECAST 0-3KM VALUES ON THE ORDER OF 10KT OR LESS.
THE LATEST SPC MESOANALYSIS SHOWED GOOD CIN OVER THE WESTERN
PIEDMONT WITH INSTABILITY...TO 2000J/KG...ALONG THE IMMEDIATE COAST.
THE RAP FORECASTS THIS CIN...ASSOCIATED WITH A LOW-LEVEL CAP AND
GOOD DEW POINT SPREADS SUCH AS NOTED ON THE 12Z KGSO SOUNDING...
ERODING THIS AFTERNOON AROUND 20Z. WHILE IN THE MID-LEVELS THERE
SHOULD BE A WEAK SHEAR AXIS AND VORTICITY CLOSER TO THE VIRGINIA
BORDER THIS AFTERNOON...BETTER LOW-LEVEL FORCING IS EXPECTED IN
SURFACE TROUGHINESS CLOSER TO THE COASTAL PLAIN WHERE THE
INSTABILITY SHOULD ALSO BE GREATER...ON THE ORDER OF 1500J/KG THIS
AFTERNOON BASED ON RAP SOUNDINGS. THE RAP FORECASTS THE BETTER LIFT
IN THAT AREA AS WELL...GRADUALLY PROPAGATING WEST IN THE LIGHT WINDS
AND WEAK SHEAR. THE VARIETIES OF HRRR WRF GUIDANCE LEAN TOWARD
INITIAL DEEP CONVECTIVE DEVELOPMENT TOWARD INTERSTATE 95 GRADUALLY
PROPAGATING NORTHWEST...STRUGGLING TO MAKE IT INTO THE TRIAD WHERE
OVERALL STABILITY SHOULD BE GREATER. FOR THE MORNING UPDATE...
DELAYED THE ONSET OF ISOLATED TO SCATTERED POPS AND TRENDED ANY TO
LATE IN THE DAY AND INTO THIS EVENING OVER THE NORTHWEST PIEDMONT.
GIVEN DCAPE FORECAST AT A MAXIMUM AROUND 700J/KG THIS AFTERNOON...
AN ISOLATED STORM COULD PRODUCE A STRONG WIND GUST...BUT INSTANCES
OF SUCH SHOULD BE PULSE-LIKE IN WEAK SHEAR AND WEAK WINDS ALOFT.
WITH GOOD SUN THROUGH THE MORNING AND A FAST RISE TO TEMPERATURES...
IN SEVERAL LOCATIONS RAISED MAXES A DEGREE OR TWO...FOR HIGHS OF 90
TO 95. APPARENT TEMPERATURES...LIKE IN THE HWO...SHOULD BE WITHIN
A DEGREE OR TWO OF 100 EAST OF ABOUT U.S. 1.
CONVECTIVE OVERTURNING AND NOCTURNAL STABILIZATION SHOULD REDUCE THE
COVERAGE OF SHOWERS AND STORMS OVERNIGHT...BUT GUIDANCE CONTINUES TO
SUGGEST THERE MAY BE A FEW CELLS AROUND. LOWS WILL BE IN THE UPPER
60S AND LOWER 70S.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
AS OF 305 AM WEDNESDAY...
THE BERMUDA HIGH BUILDS BACK ACROSS THE REGION ON THURSDAY...WITH A
SOUTHERLY WIND DEVELOPING ACROSS THE AREA. MOISTURE CONTENT REMAINS
HIGH WITH PW NEAR 2 INCHES AND MODERATE INSTABILITY AGAIN IN THE
AFTERNOON. WITHOUT A PRE-EXISTING TROUGH/BOUNDARY...CONVECTION
SHOULD BE A LITTLE MORE FOCUSED ALONG THE HIGHER TERRAIN AND/OR
SEABREEZE...THOUGH BOTH THE GFS AND ECMWF SUGGEST AT LEAST SCATTERED
COVERAGE ACROSS CENTRAL THURSDAY AFTERNOON. H85 TEMPS AND LOW-LEVEL
THICKNESSES ARE RELATIVELY UNCHANGED FROM WEDNESDAY...THOUGH
NAM/ECMWF STATISTICAL GUIDANCE ARE A COUPLE DEGREES COOLER. WILL
INDICATE HIGHS AGAIN MOSTLY IN THE LOWER 90S. LOWS THURSDAY NIGHT IN
THE UPPER 60S AND LOWER 70S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 330 AM WEDNESDAY...
THE SUB-TROPICAL RIDGE WILL BRIEFLY EXPAND NORTH INTO THE OH VALLEY
AND MIDDLE ATLANTIC...AND CONSEQUENTLY CAUSE THE MID LEVEL SHEAR AND
MOIST AXIS SETTLING INTO CENTRAL NC THIS MORNING...TO WEAKEN AND BOW
NORTH INTO VA FRI-SAT. MEDIUM RANGE ENSEMBLE GUIDANCE SUGGESTS THE
SUB-TROPICAL RIDGE WILL THEN WEAKEN AND BECOME SUPPRESSED...BY A
PAIR OF SHORTWAVE TROUGHS FORECAST TO CROSS THE NE US AND SE CANADA
IN PROGRESSIVE FLOW ALOFT THROUGH THE END OF THE WEEKEND. GUIDANCE
IS ALSO IN AGREEMENT THAT SOME DEGREE OF TROUGHING WILL BE LEFT
BEHIND IN A POSITIVE TILT FASHION OVER THE MIDDLE ATLANTIC...THOUGH
THE DEGREE OF WHICH REMAINS UNCERTAIN DUE TO ABOVE AVERAGE MODEL
SPREAD OF THE H5 PATTERN BY DAYS 6-7 (MON-TUE). THE EBB AND FLOW OF
THE PATTERN ALOFT...AND ASSOCIATED SUPPRESSION OF THE SUB-TROPICAL
RIDGE...WILL ALLOW THE POLAR FRONT TO SETTLE SE THROUGH CENTRAL NC
CENTERED AROUND THE DAY SUNDAY...BEFORE SLOWING AS IT DRIFTS
OFFSHORE AND INTO THE VICINITY OF THE GULF STREAM THROUGH MID-WEEK.
A WEAK WAVE OF LOW PRESSURE...OR TWO...ARE APT TO DEVELOP ALONG THE
SLOWING FRONT...AS THE AFOREMENTIONED POSITIVELY TILTED TROUGH ALOFT
INTERACTS WITH SEASONABLY STRONG BAROCLINICITY DRIVEN BY THE
INCOMING COOL/DRY CANADIAN AIR MASS INTO THE WARM/MOIST GULF STREAM
WATERS.
FRI-SAT: A PATTERN OF WEAK SYNOPTIC-SCALE ASCENT AHEAD OF THE
AFOREMENTIONED POLAR FRONT WILL FAVOR NEAR CLIMO PROBABILITIES OF
DIURNALLY-DRIVEN CONVECTION ALONG THE SEA BREEZE AND MOUNTAINS...
BOTH OF WHICH WILL BE APT TO PROPAGATE INTO THE WESTERN AND EASTERN
EDGES OF THE RAH CWFA EACH AFTERNOON AND EVENING. THE DISSIPATION
AND NORTHWARD DEPARTURE OF MID-HIGH CLOUDINESS ASSOCIATED WITH THE
AFOREMENTIONED SHEAR AXIS ALOFT...RESULTING FROM THE BRIEFLY
BUILDING SUB-TROPICAL RIDGE...SHOULD ALLOW FULL-SUN (OR NEARLY SO)
H85 TEMPS IN THE 17-18C RANGE TO BE REALIZED...SUPPORTIVE OF HIGHS
OF 88 TO 93 DEGREES. SAT NIGHT-SUN: THE BEST CHANCE OF SHOWERS AND
STORMS DURING THE LONG TERM PERIOD WILL UNDOUBTEDLY ACCOMPANY THE
ARRIVAL/PASSAGE OF THE POLAR FRONT...ONE WHOSE LOW LEVEL FRONTAL
CIRCULATION WILL BE SUPPORTED THROUGH THE MID-UPPER LEVELS BY
PERSISTENT RIGHT ENTRANCE REGION UPPER JET FORCING. THE COMBINATION
OF INCREASING MID-HIGH CLOUDS AND NUMEROUS TO WIDESPREAD SHOWERS AND
STORMS SHOULD HOLD TEMPERATURES GENERALLY IN THE LOWER TO MIDDLE
80S.
SUN NIGHT-MON NIGHT: SUBSIDENCE DRYING AND LESSENING PROBABILITIES
OF RAIN WILL DEVELOP FROM NW TO SE...BUT NORTHEASTERLY LOW-MID LEVEL
FLOW ON THE WEST SIDE OF THE FRONTAL ZONE AND PROBABLE WAVES OF LOW
PRESSURE WILL RESULT IN MOSTLY CLOUDY CONDITIONS AND A CHANCE OF
RAIN OVER THE EASTERN CWFA...RANGING TO PARTIAL SUNSHINE AND
GENERALLY DRY CONDITIONS OVER THE WESTERN PIEDMONT. COOLER WITH
HIGHS IN THE UPPER 70S TO LOWER 80S.
TUE: SFC WAVES DEPART WITH LESSENING INFLUENCE OF THE NORTHEASTERLY
FLOW...AND INCREASING AMOUNTS OF SUNSHINE. MILD WITH HIGHS AGAIN IN
THE UPPER 70S TO LOWER OR PERHAPS MIDDLE 80S.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
AS OF 1055 AM WEDNESDAY...
VFR CONDITIONS ARE EXPECTED TO PREVAIL THIS AFTERNOON THROUGH THIS
EVENING OUTSIDE OF DEEP CONVECTION. SHOWERS AND STORMS ARE EXPECTED
TO DEVELOP BY THIS AFTERNOON IN THE VICINITY OF A SURFACE TROUGH
OVER THE AREA. WEAK STEERING FLOW AND THE POTENTIAL FOR VARIOUS
OUTFLOW BOUNDARIES MAKE IT DIFFICULT TO TIME CONVECTION AT ANY
SPECIFIC TAF SITE...BUT THE PRESENCE OF THE TROUGH LENDS BETTER
CHANCES TO KFAY...KRWI AND KRDU. HOWEVER...CONFIDENCE IS FAIRLY HIGH
THAT ANY TERMINAL COULD SEE A SHOWER OR STORM THIS AFTERNOON AND
EVENING. A LIGHT SOUTHERLY WIND IS EXPECTED TO REDEVELOP
TONIGHT...WHICH MAY INDUCE PATCHY STRATUS ACROSS THE AREA BY
THURSDAY MORNING.
OUTLOOK...AFTERNOON SHOWERS AND STORMS...AS WELL AS EARLY MORNING
STRATUS/FOG WILL BE POSSIBLE EACH DAY THIS WEEK. AN APPROACHING
COLD FRONT WILL LIKELY ENHANCE THE COVERAGE OF SHOWERS/STORMS LATE
THIS WEEKEND INTO EARLY NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...DJF/BLS
SHORT TERM...BLS
LONG TERM...MWS
AVIATION...DJF/BLS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
730 AM EDT WED SEP 3 2014
.SYNOPSIS...A WEAK SURFACE FRONT WILL SETTLE SOUTHWARD ACROSS
CENTRAL NC TODAY. HIGH PRESSURE WILL BUILD BACK OVER THE AREA FOR
THE REMAINDER OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 305 AM WEDNESDAY...
A FEW SHOWERS POPPING UP ALONG REMNANT OUTFLOW FROM CONVECTION
CROSSING THE MOUNTAINS LATE LAST EVENING WILL CONTINUE TO MOVE OFF
TO THE NORTHEAST ACROSS THE NORTHERN PIEDMONT THIS MORNING.
LINGERING INSTABILITY AND RECENT RADAR TRENDS SUGGEST THAT A COUPLE
ISOLATED THUNDERSTORMS ARE POSSIBLE AS WELL. THE OUTLFOW WILL
SETTLE SOUTH THIS MORNING AND SHOULD PRETTY MUCH BISECT THE AREA
FROM SOUTHWEST TO NORTHEAST BASED ON THE LATEST RAP FORECAST. THERE
IS NO REAL AIRMASS CHANGE ACROSS THE AREA AND THE BLENDED TOTAL PW
PRODUCT SHOWS PW VALUES OF 1.8 TO 2 INCHES HIS MORNING. H85 TEMPS
ARE DOWN A COUPLE DEGREES FROM THE LATEST COUPLE OF DAYS AND HIGHS
SHOULD ONLY BE IN THE LOW TO MID 90S TODAY. HOWEVER..THE STRONG
HEATING COMBINED WITH THE MOIST AIRMASS WILL LEAD TO MODERATE
INSTABILITY AGAIN THIS AFTERNOON. LOW-LEVEL CONVERGENCE AND A
REMNANT DISTURBANCE/SHEAR AXIS ALOFT WILL SERVE AS A TRIGGER FOR
SCATTERED TO SOMETIMES NUMEROUS SHOWERS AND STORMS...AND WHILE
MOISTURE/INSTABILITY SHOULD FAVOR BETTER COVERAGE ACROSS THE
SOUTH...WEAK STEERING FLOW AND PROPAGATING OUTFLOWS MAKES IT
DIFFICULT TO ASSESS WHERE STORM COVERAGE WILL BE THE GREATEST. MOST
HIRES GUIDANCE SHOWS STORMS DEVELOPING ACROSS THE SOUTH BY 19Z AND
THEN SHIFTING NORTHWARD AS THE AFOREMENTIONED BOUNDARY WASHES OUT.
HEAVY RAIN...MINOR FLOODING AND A FEW STRONG WIND GUSTS WILL BE THE
MAIN STORM THREATS.
CONVECTIVE OVERTURNING AND NOCTURNAL STABILIZATION SHOULD REDUCE THE
COVERAGE OF SHOWERS AND STORMS OVERNIGHT...BUT GUIDANCE CONTINUES TO
SUGGEST THERE MAY BE A FEW CELLS AROUND. LOWS WILL BE IN THE UPPER
60S AND LOWER 70S.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
AS OF 305 AM WEDNESDAY...
THE BERMUDA HIGH BUILDS BACK ACROSS THE REGION ON THURSDAY...WITH A
SOUTHERLY WIND DEVELOPING ACROSS THE AREA. MOISTURE CONTENT REMAINS
HIGH WITH PW NEAR 2 INCHES AND MODERATE INSTABILITY AGAIN IN THE
AFTERNOON. WITHOUT A PRE-EXISTING TROUGH/BOUNDARY...CONVECTION
SHOULD BE A LITTLE MORE FOCUSED ALONG THE HIGHER TERRAIN AND/OR
SEABREEZE...THOUGH BOTH THE GFS AND ECMWF SUGGEST AT LEAST SCATTERED
COVERAGE ACROSS CENTRAL THURSDAY AFTERNOON. H85 TEMPS AND LOW-LEVEL
THICKNESSES ARE RELATIVELY UNCHANGED FROM WEDNESDAY...THOUGH
NAM/ECMWF STATISTICAL GUIDANCE ARE A COUPLE DEGREES COOLER. WILL
INDICATE HIGHS AGAIN MOSTLY IN THE LOWER 90S. LOWS THURSDAY NIGHT IN
THE UPPER 60S AND LOWER 70S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 330 AM WEDNESDAY...
THE SUB-TROPICAL RIDGE WILL BRIEFLY EXPAND NORTH INTO THE OH VALLEY
AND MIDDLE ATLANTIC...AND CONSEQUENTLY CAUSE THE MID LEVEL SHEAR AND
MOIST AXIS SETTLING INTO CENTRAL NC THIS MORNING...TO WEAKEN AND BOW
NORTH INTO VA FRI-SAT. MEDIUM RANGE ENSEMBLE GUIDANCE SUGGESTS THE
SUB-TROPICAL RIDGE WILL THEN WEAKEN AND BECOME SUPPRESSED...BY A
PAIR OF SHORTWAVE TROUGHS FORECAST TO CROSS THE NE US AND SE CANADA
IN PROGRESSIVE FLOW ALOFT THROUGH THE END OF THE WEEKEND. GUIDANCE
IS ALSO IN AGREEMENT THAT SOME DEGREE OF TROUGHING WILL BE LEFT
BEHIND IN A POSITIVE TILT FASHION OVER THE MIDDLE ATLANTIC...THOUGH
THE DEGREE OF WHICH REMAINS UNCERTAIN DUE TO ABOVE AVERAGE MODEL
SPREAD OF THE H5 PATTERN BY DAYS 6-7 (MON-TUE). THE EBB AND FLOW OF
THE PATTERN ALOFT...AND ASSOCIATED SUPPRESSION OF THE SUB-TROPICAL
RIDGE...WILL ALLOW THE POLAR FRONT TO SETTLE SE THROUGH CENTRAL NC
CENTERED AROUND THE DAY SUNDAY...BEFORE SLOWING AS IT DRIFTS
OFFSHORE AND INTO THE VICINITY OF THE GULF STREAM THROUGH MID-WEEK.
A WEAK WAVE OF LOW PRESSURE...OR TWO...ARE APT TO DEVELOP ALONG THE
SLOWING FRONT...AS THE AFOREMENTIONED POSITIVELY TILTED TROUGH ALOFT
INTERACTS WITH SEASONABLY STRONG BAROCLINICITY DRIVEN BY THE
INCOMING COOL/DRY CANADIAN AIR MASS INTO THE WARM/MOIST GULF STREAM
WATERS.
FRI-SAT: A PATTERN OF WEAK SYNOPTIC-SCALE ASCENT AHEAD OF THE
AFOREMENTIONED POLAR FRONT WILL FAVOR NEAR CLIMO PROBABILITIES OF
DIURNALLY-DRIVEN CONVECTION ALONG THE SEA BREEZE AND MOUNTAINS...
BOTH OF WHICH WILL BE APT TO PROPAGATE INTO THE WESTERN AND EASTERN
EDGES OF THE RAH CWFA EACH AFTERNOON AND EVENING. THE DISSIPATION
AND NORTHWARD DEPARTURE OF MID-HIGH CLOUDINESS ASSOCIATED WITH THE
AFOREMENTIONED SHEAR AXIS ALOFT...RESULTING FROM THE BRIEFLY
BUILDING SUB-TROPICAL RIDGE...SHOULD ALLOW FULL-SUN (OR NEARLY SO)
H85 TEMPS IN THE 17-18C RANGE TO BE REALIZED...SUPPORTIVE OF HIGHS
OF 88 TO 93 DEGREES. SAT NIGHT-SUN: THE BEST CHANCE OF SHOWERS AND
STORMS DURING THE LONG TERM PERIOD WILL UNDOUBTEDLY ACCOMPANY THE
ARRIVAL/PASSAGE OF THE POLAR FRONT...ONE WHOSE LOW LEVEL FRONTAL
CIRCULATION WILL BE SUPPORTED THROUGH THE MID-UPPER LEVELS BY
PERSISTENT RIGHT ENTRANCE REGION UPPER JET FORCING. THE COMBINATION
OF INCREASING MID-HIGH CLOUDS AND NUMEROUS TO WIDESPREAD SHOWERS AND
STORMS SHOULD HOLD TEMPERATURES GENERALLY IN THE LOWER TO MIDDLE
80S.
SUN NIGHT-MON NIGHT: SUBSIDENCE DRYING AND LESSENING PROBABILITIES
OF RAIN WILL DEVELOP FROM NW TO SE...BUT NORTHEASTERLY LOW-MID LEVEL
FLOW ON THE WEST SIDE OF THE FRONTAL ZONE AND PROBABLE WAVES OF LOW
PRESSURE WILL RESULT IN MOSTLY CLOUDY CONDITIONS AND A CHANCE OF
RAIN OVER THE EASTERN CWFA...RANGING TO PARTIAL SUNSHINE AND
GENERALLY DRY CONDITIONS OVER THE WESTERN PIEDMONT. COOLER WITH
HIGHS IN THE UPPER 70S TO LOWER 80S.
TUE: SFC WAVES DEPART WITH LESSENING INFLUENCE OF THE NORTHEASTERLY
FLOW...AND INCREASING AMOUNTS OF SUNSHINE. MILD WITH HIGHS AGAIN IN
THE UPPER 70S TO LOWER OR PERHAPS MIDDLE 80S.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 730 AM WEDNESDAY...
ONCE THE BRIEF MVFR VSBYS AT KRWI IMPROVE...LIKELY BY 13Z...VFR
CONDITIONS ARE EXPECTED TO PREVAIL OUTSIDE OF CONVECTION. SHOWERS
AND STORMS ARE EXPECTED TO DEVELOP BY THIS AFTERNOON IN THE VICINITY
OF A SURFACE TROUGH OVER THE AREA. WEAK STEERING FLOW AND THE
POTENTIAL FOR VARIOUS OUTFLOW BOUNDARIES MAKE IT DIFFICULT TO TIME
CONVECTION AT ANY SPECIFIC TAF SITE...BUT THE PRESENCE OF THE TROUGH
LENDS BETTER CHANCES TO KFAY...KRWI AND KRDU. HOWEVER... CONFIDENCE
IS FAIRLY HIGH THAT ANY TERMINAL COULD SEE A SHOWER OR STORM THIS
AFTERNOON/EVENING.
A LIGHT SOUTHERLY WIND IS EXPECTED TO REDEVELOP TONIGHT...WHICH MAY
INDUCE PATCHY STRATUS ACROSS THE AREA BY THURSDAY MORNING.
OUTLOOK...AFTERNOON SHOWERS AND STORMS...AS WELL AS EARLY MORNING
STRATUS/FOG WILL BE POSSIBLE EACH DAY THIS WEEK. AN APPROACHING
COLD FRONT WILL LIKELY ENHANCE THE COVERAGE OF SHOWERS/STORMS LATE
THIS WEEKEND INTO EARLY NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BSD/WSS
NEAR TERM...BLS
SHORT TERM...BLS
LONG TERM...MWS
AVIATION...BLS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
330 AM EDT WED SEP 3 2014
.SYNOPSIS...A WEAK SURFACE FRONT WILL SETTLE SOUTHWARD ACROSS
CENTRAL NC TODAY. HIGH PRESSURE WILL BUILD BACK OVER THE AREA FOR
THE REMAINDER OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 305 AM WEDNESDAY...
A FEW SHOWERS POPPING UP ALONG REMNANT OUTFLOW FROM CONVECTION
CROSSING THE MOUNTAINS LATE LAST EVENING WILL CONTINUE TO MOVE OFF
TO THE NORTHEAST ACROSS THE NORTHERN PIEDMONT THIS MORNING.
LINGERING INSTABILITY AND RECENT RADAR TRENDS SUGGEST THAT A COUPLE
ISOLATED THUNDERSTORMS ARE POSSIBLE AS WELL. THE OUTLFOW WILL
SETTLE SOUTH THIS MORNING AND SHOULD PRETTY MUCH BISECT THE AREA
FROM SOUTHWEST TO NORTHEAST BASED ON THE LATEST RAP FORECAST. THERE
IS NO REAL AIRMASS CHANGE ACROSS THE AREA AND THE BLENDED TOTAL PW
PRODUCT SHOWS PW VALUES OF 1.8 TO 2 INCHES HIS MORNING. H85 TEMPS
ARE DOWN A COUPLE DEGREES FROM THE LATEST COUPLE OF DAYS AND HIGHS
SHOULD ONLY BE IN THE LOW TO MID 90S TODAY. HOWEVER..THE STRONG
HEATING COMBINED WITH THE MOIST AIRMASS WILL LEAD TO MODERATE
INSTABILITY AGAIN THIS AFTERNOON. LOW-LEVEL CONVERGENCE AND A
REMNANT DISTURBANCE/SHEAR AXIS ALOFT WILL SERVE AS A TRIGGER FOR
SCATTERED TO SOMETIMES NUMEROUS SHOWERS AND STORMS...AND WHILE
MOISTURE/INSTABILITY SHOULD FAVOR BETTER COVERAGE ACROSS THE
SOUTH...WEAK STEERING FLOW AND PROPAGATING OUTFLOWS MAKES IT
DIFFICULT TO ASSESS WHERE STORM COVERAGE WILL BE THE GREATEST. MOST
HIRES GUIDANCE SHOWS STORMS DEVELOPING ACROSS THE SOUTH BY 19Z AND
THEN SHIFTING NORTHWARD AS THE AFOREMENTIONED BOUNDARY WASHES OUT.
HEAVY RAIN...MINOR FLOODING AND A FEW STRONG WIND GUSTS WILL BE THE
MAIN STORM THREATS.
CONVECTIVE OVERTURNING AND NOCTURNAL STABILIZATION SHOULD REDUCE THE
COVERAGE OF SHOWERS AND STORMS OVERNIGHT...BUT GUIDANCE CONTINUES TO
SUGGEST THERE MAY BE A FEW CELLS AROUND. LOWS WILL BE IN THE UPPER
60S AND LOWER 70S.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
AS OF 305 AM WEDNESDAY...
THE BERMUDA HIGH BUILDS BACK ACROSS THE REGION ON THURSDAY...WITH A
SOUTHERLY WIND DEVELOPING ACROSS THE AREA. MOISTURE CONTENT REMAINS
HIGH WITH PW NEAR 2 INCHES AND MODERATE INSTABILITY AGAIN IN THE
AFTERNOON. WITHOUT A PRE-EXISTING TROUGH/BOUNDARY...CONVECTION
SHOULD BE A LITTLE MORE FOCUSED ALONG THE HIGHER TERRAIN AND/OR
SEABREEZE...THOUGH BOTH THE GFS AND ECMWF SUGGEST AT LEAST SCATTERED
COVERAGE ACROSS CENTRAL THURSDAY AFTERNOON. H85 TEMPS AND LOW-LEVEL
THICKNESSES ARE RELATIVELY UNCHANGED FROM WEDNESDAY...THOUGH
NAM/ECMWF STATISTICAL GUIDANCE ARE A COUPLE DEGREES COOLER. WILL
INDICATE HIGHS AGAIN MOSTLY IN THE LOWER 90S. LOWS THURSDAY NIGHT IN
THE UPPER 60S AND LOWER 70S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 330 AM WEDNESDAY...
THE SUB-TROPICAL RIDGE WILL BRIEFLY EXPAND NORTH INTO THE OH VALLEY
AND MIDDLE ATLANTIC...AND CONSEQUENTLY CAUSE THE MID LEVEL SHEAR AND
MOIST AXIS SETTLING INTO CENTRAL NC THIS MORNING...TO WEAKEN AND BOW
NORTH INTO VA FRI-SAT. MEDIUM RANGE ENSEMBLE GUIDANCE SUGGESTS THE
SUB-TROPICAL RIDGE WILL THEN WEAKEN AND BECOME SUPPRESSED...BY A
PAIR OF SHORTWAVE TROUGHS FORECAST TO CROSS THE NE US AND SE CANADA
IN PROGRESSIVE FLOW ALOFT THROUGH THE END OF THE WEEKEND. GUIDANCE
IS ALSO IN AGREEMENT THAT SOME DEGREE OF TROUGHING WILL BE LEFT
BEHIND IN A POSITIVE TILT FASHION OVER THE MIDDLE ATLANTIC...THOUGH
THE DEGREE OF WHICH REMAINS UNCERTAIN DUE TO ABOVE AVERAGE MODEL
SPREAD OF THE H5 PATTERN BY DAYS 6-7 (MON-TUE). THE EBB AND FLOW OF
THE PATTERN ALOFT...AND ASSOCIATED SUPPRESSION OF THE SUB-TROPICAL
RIDGE...WILL ALLOW THE POLAR FRONT TO SETTLE SE THROUGH CENTRAL NC
CENTERED AROUND THE DAY SUNDAY...BEFORE SLOWING AS IT DRIFTS
OFFSHORE AND INTO THE VICINITY OF THE GULF STREAM THROUGH MID-WEEK.
A WEAK WAVE OF LOW PRESSURE...OR TWO...ARE APT TO DEVELOP ALONG THE
SLOWING FRONT...AS THE AFOREMENTIONED POSITIVELY TILTED TROUGH ALOFT
INTERACTS WITH SEASONABLY STRONG BAROCLINICITY DRIVEN BY THE
INCOMING COOL/DRY CANADIAN AIR MASS INTO THE WARM/MOIST GULF STREAM
WATERS.
FRI-SAT: A PATTERN OF WEAK SYNOPTIC-SCALE ASCENT AHEAD OF THE
AFOREMENTIONED POLAR FRONT WILL FAVOR NEAR CLIMO PROBABILITIES OF
DIURNALLY-DRIVEN CONVECTION ALONG THE SEA BREEZE AND MOUNTAINS...
BOTH OF WHICH WILL BE APT TO PROPAGATE INTO THE WESTERN AND EASTERN
EDGES OF THE RAH CWFA EACH AFTERNOON AND EVENING. THE DISSIPATION
AND NORTHWARD DEPARTURE OF MID-HIGH CLOUDINESS ASSOCIATED WITH THE
AFOREMENTIONED SHEAR AXIS ALOFT...RESULTING FROM THE BRIEFLY
BUILDING SUB-TROPICAL RIDGE...SHOULD ALLOW FULL-SUN (OR NEARLY SO)
H85 TEMPS IN THE 17-18C RANGE TO BE REALIZED...SUPPORTIVE OF HIGHS
OF 88 TO 93 DEGREES. SAT NIGHT-SUN: THE BEST CHANCE OF SHOWERS AND
STORMS DURING THE LONG TERM PERIOD WILL UNDOUBTEDLY ACCOMPANY THE
ARRIVAL/PASSAGE OF THE POLAR FRONT...ONE WHOSE LOW LEVEL FRONTAL
CIRCULATION WILL BE SUPPORTED THROUGH THE MID-UPPER LEVELS BY
PERSISTENT RIGHT ENTRANCE REGION UPPER JET FORCING. THE COMBINATION
OF INCREASING MID-HIGH CLOUDS AND NUMEROUS TO WIDESPREAD SHOWERS AND
STORMS SHOULD HOLD TEMPERATURES GENERALLY IN THE LOWER TO MIDDLE
80S.
SUN NIGHT-MON NIGHT: SUBSIDENCE DRYING AND LESSENING PROBABILITIES
OF RAIN WILL DEVELOP FROM NW TO SE...BUT NORTHEASTERLY LOW-MID LEVEL
FLOW ON THE WEST SIDE OF THE FRONTAL ZONE AND PROBABLE WAVES OF LOW
PRESSURE WILL RESULT IN MOSTLY CLOUDY CONDITIONS AND A CHANCE OF
RAIN OVER THE EASTERN CWFA...RANGING TO PARTIAL SUNSHINE AND
GENERALLY DRY CONDITIONS OVER THE WESTERN PIEDMONT. COOLER WITH
HIGHS IN THE UPPER 70S TO LOWER 80S.
TUE: SFC WAVES DEPART WITH LESSENING INFLUENCE OF THE NORTHEASTERLY
FLOW...AND INCREASING AMOUNTS OF SUNSHINE. MILD WITH HIGHS AGAIN IN
THE UPPER 70S TO LOWER OR PERHAPS MIDDLE 80S.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
AS OF 150 AM WEDNESDAY...
A LINE OF SHOWERS AND STORMS CROSSING THE MOUNTAINS HAS WEAKENED
DRAMATICALLY SINCE 04Z. OUTFLOW AHEAD OF THE DISSIPATING CONVECTION
MAY STILL TRIGGER A FEW ISOLATED SHOWERS EARLY THIS MORNING...WITH
HIRES MODELS SHOWING A FEW SHOWERS FROM KRDU NORTH BY 09Z.
MEANWHILE...PATCHY STRATUS WILL BE POSSIBLE BY 12Z...WITH SLIGHTLY
HIGHER CHANCES AT KGSO/KINT AND KFAY BASED ON FORECAST SOUNDINGS.
HOWEVER..CONFIDENCE IN IFR OR LIFR CEILINGS IS STILL LOW AT THIS
TIME.
ADDITIONAL SHOWERS AND STORMS ARE EXPECTED TO DEVELOP BY THIS
AFTERNOON AS A THIS MORNINGS OUTFLOW AND A SURFACE TROUGH WILL
LIKELY SERVE AS A FOCUS FOR CONVECTION. WEAK STEERING FLOW AND THE
POTENTIAL FOR VARIOUS OUTFLOW BOUNDARIES MAKE IT DIFFICULT TO TIME
CONVECTION AT ANY SPECIFIC TAF SITE...BUT CONFIDENCE IS FAIRLY HIGH
THAT ANY TERMINAL COULD SEE A SHOWER OR STORM THIS AFTERNOON/EVENING.
OUTLOOK...AFTERNOON SHOWERS AND STORMS...AS WELL AS EARLY MORNING
STRATUS/FOG WILL BE POSSIBLE EACH DAY THIS WEEK. AN APPROACHING
COLD FRONT WILL LIKELY ENHANCE THE COVERAGE OF SHOWERS/STORMS LATE
THIS WEEKEND INTO EARLY NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BSD/WSS
NEAR TERM...BLS
SHORT TERM...BLS
LONG TERM...MWS
AVIATION...BLS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
310 AM EDT WED SEP 3 2014
.SYNOPSIS...A WEAK SURFACE FRONT WILL SETTLE SOUTHWARD ACROSS
CENTRAL NC TODAY. HIGH PRESSURE WILL BUILD BACK OVER THE AREA FOR
THE REMAINDER OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 305 AM WEDNESDAY...
A FEW SHOWERS POPPING UP ALONG REMNANT OUTFLOW FROM CONVECTION
CROSSING THE MOUNTAINS LATE LAST EVENING WILL CONTINUE TO MOVE OFF
TO THE NORTHEAST ACROSS THE NORTHERN PIEDMONT THIS MORNING.
LINGERING INSTABILITY AND RECENT RADAR TRENDS SUGGEST THAT A COUPLE
ISOLATED THUNDERSTORMS ARE POSSIBLE AS WELL. THE OUTLFOW WILL
SETTLE SOUTH THIS MORNING AND SHOULD PRETTY MUCH BISECT THE AREA
FROM SOUTHWEST TO NORTHEAST BASED ON THE LATEST RAP FORECAST. THERE
IS NO REAL AIRMASS CHANGE ACROSS THE AREA AND THE BLENDED TOTAL PW
PRODUCT SHOWS PW VALUES OF 1.8 TO 2 INCHES HIS MORNING. H85 TEMPS
ARE DOWN A COUPLE DEGREES FROM THE LATEST COUPLE OF DAYS AND HIGHS
SHOULD ONLY BE IN THE LOW TO MID 90S TODAY. HOWEVER..THE STRONG
HEATING COMBINED WITH THE MOIST AIRMASS WILL LEAD TO MODERATE
INSTABILITY AGAIN THIS AFTERNOON. LOW-LEVEL CONVERGENCE AND A
REMNANT DISTURBANCE/SHEAR AXIS ALOFT WILL SERVE AS A TRIGGER FOR
SCATTERED TO SOMETIMES NUMEROUS SHOWERS AND STORMS...AND WHILE
MOISTURE/INSTABILITY SHOULD FAVOR BETTER COVERAGE ACROSS THE
SOUTH...WEAK STEERING FLOW AND PROPAGATING OUTFLOWS MAKES IT
DIFFICULT TO ASSESS WHERE STORM COVERAGE WILL BE THE GREATEST. MOST
HIRES GUIDANCE SHOWS STORMS DEVELOPING ACROSS THE SOUTH BY 19Z AND
THEN SHIFTING NORTHWARD AS THE AFOREMENTIONED BOUNDARY WASHES OUT.
HEAVY RAIN...MINOR FLOODING AND A FEW STRONG WIND GUSTS WILL BE THE
MAIN STORM THREATS.
CONVECTIVE OVERTURNING AND NOCTURNAL STABILIZATION SHOULD REDUCE THE
COVERAGE OF SHOWERS AND STORMS OVERNIGHT...BUT GUIDANCE CONTINUES TO
SUGGEST THERE MAY BE A FEW CELLS AROUND. LOWS WILL BE IN THE UPPER
60S AND LOWER 70S.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
AS OF 305 AM WEDNESDAY...
THE BERMUDA HIGH BUILDS BACK ACROSS THE REGION ON THURSDAY...WITH A
SOUTHERLY WIND DEVELOPING ACROSS THE AREA. MOISTURE CONTENT REMAINS
HIGH WITH PW NEAR 2 INCHES AND MODERATE INSTABILITY AGAIN IN THE
AFTERNOON. WITHOUT A PRE-EXISTING TROUGH/BOUNDARY...CONVECTION
SHOULD BE A LITTLE MORE FOCUSED ALONG THE HIGHER TERRAIN AND/OR
SEABREEZE...THOUGH BOTH THE GFS AND ECMWF SUGGEST AT LEAST SCATTERED
COVERAGE ACROSS CENTRAL THURSDAY AFTERNOON. H85 TEMPS AND LOW-LEVEL
THICKNESSES ARE RELATIVELY UNCHANGED FROM WEDNESDAY...THOUGH
NAM/ECMWF STATISTICAL GUIDANCE ARE A COUPLE DEGREES COOLER. WILL
INDICATE HIGHS AGAIN MOSTLY IN THE LOWER 90S. LOWS THURSDAY NIGHT IN
THE UPPER 60S AND LOWER 70S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 255 PM TUESDAY...
FOR THU/FRI: CONTINUED WARM/HUMID WITH DAILY SCATTERED SHOWERS AND
STORMS. AT THE SURFACE... THE WEAK FRONTAL ZONE WILL LIKELY HAVE
WASHED OUT BY THU MORNING... AND THE SURFACE HIGH CENTERED OFF THE
SOUTHEAST COAST WILL INTRODUCE A MOIST CONFLUENT LOW LEVEL FLOW OFF
THE ATLANTIC INTO NC. A POSITIVELY TILTED TROUGH WILL SHIFT FROM
MT/DAKOTAS/SCENTRAL CANADA EARLY THU ACROSS ONT/QUE BY FRI NIGHT...
PROPELLING A COLD FRONT THROUGH THE GREAT LAKES/MID MISS VALLEY. AS
THE FLAT RIDGE HOLDS ACROSS THE SOUTHEAST/MIDSOUTH/GULF STATES
HOWEVER... WE`LL STAY WITHIN AN ENVIRONMENT CHARACTERIZED BY WEAK
SHEAR AND MODERATE INSTABILITY (TEMPERED BY WARM MID LEVELS). PW
VALUES SHOULD STAY ABOVE NORMAL AT 1.7-1.9"... NOT UNEXPECTED GIVEN
THE TROPICAL NATURE OF THE INCOMING AIR MASS... AND SUFFICIENT TO
SUPPORT SCATTERED CONVECTION ALONG THE SEA BREEZE... DYING FRONTAL
ZONE... OR ANY OTHER SUBTLE BOUNDARY. WILL RETAIN AFTERNOON AND
EVENING STORM CHANCES BOTH DAYS... WITH TEMPS HOLDING ABOUT A
CATEGORY ABOVE NORMAL AS THICKNESSES STAY AROUND 10 M ABOVE NORMAL.
FOR SAT-TUE: STILL EXPECT A TRANSITION FROM THE WARM/HUMID WEATHER
TO MORE SEASONABLE CONDITIONS LATE IN THE WEEKEND. THE INITIAL MID
LEVEL TROUGH OVER ERN QUEBEC WILL CONTINUE SHIFTING EAST OVER THE
MARITIMES... WHILE A STRONG SLUG OF STRONG VORTICITY EMANATING FROM
A STRONG COLD VORTEX OVER THE BEAUFORT SEA WILL PUSH EASTWARD CLOSE
ON ITS HEELS... CROSSING HUDSON BAY ON SUNDAY. THIS SHOULD PUSH THE
SURFACE COLD FRONT TO JUST NW OF NC BY SUN... AND WELL INTO THE
STATE BY EARLY MON. BOTH THE GFS AND ECMWF TRACK THEIR COOL PARENT
HIGHS OVER THE ST LAWRENCE VALLEY/SRN QUEBEC MON/TUE... WITH THE
COLD FRONT PUSHING TO ERN NC AND ACROSS NWRN SC. THIS MODEL
AGREEMENT LEADS TO GROWING CONFIDENCE THAT THE PARENT HIGH WILL BE
DENSE ENOUGH TO PUSH THIS COOLER AIR WELL INTO CENTRAL NC...
ALTHOUGH IT MAY NOT HAPPEN UNTIL LATE SUN NIGHT INTO MON MORNING.
WILL FOLLOW THIS TREND WITH TEMPS HOLDING ABOVE NORMAL SAT/SUN (BUT
NOT AS WARM IN THE NORTH SUN DUE TO MORE CLOUDS) WITH HIGHS IN THE
MID 80S TO NEAR 90... BUT THEN EXPECT TEMPS TO PLUNGE FOR MON/TUE
WITH THICKNESSES DROPPING TO 10-20 M BELOW NORMAL... YIELDING HIGHS
NEAR 80 TO LOWER 80S. REGARDING PRECIP CHANCES... WE`RE LIKELY TO
SEE SCATTERED TO PERHAPS NUMEROUS SHOWERS AND STORMS LATE SAT
THROUGH AT LEAST SUN NIGHT... BOTH ALONG THE PREFRONTAL PIEDMONT
TROUGH AND AHEAD OF AND WITH THE FRONT ITSELF. SHOWER/STORM CHANCES
ARE EXPECTED TO PEAK SUN AFTERNOON. WITH THE MID LEVEL TROUGH AXIS
SWINGING THROUGH THE REGION MON... WE MAY SEE LINGERING CHANCES FOR
RAIN ESPECIALLY SOUTH AND EAST. THE SURFACE RIDGE NOSING IN FROM THE
NORTH LATE MON INTO TUE ACCOMPANIED BY LOWERING PW VALUES SHOULD
MEAN MOSTLY DRY WEATHER TUE... AS THE MID LEVEL TROUGH AXIS LIFTS NE
AWAY FROM THE REGION FOLLOWED BY WEAK MID LEVEL SHORTWAVE RIDGING
OVER THE CAROLINAS. -GIH
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
AS OF 150 AM WEDNESDAY...
A LINE OF SHOWERS AND STORMS CROSSING THE MOUNTAINS HAS WEAKENED
DRAMATICALLY SINCE 04Z. OUTFLOW AHEAD OF THE DISSIPATING CONVECTION
MAY STILL TRIGGER A FEW ISOLATED SHOWERS EARLY THIS MORNING...WITH
HIRES MODELS SHOWING A FEW SHOWERS FROM KRDU NORTH BY 09Z.
MEANWHILE...PATCHY STRATUS WILL BE POSSIBLE BY 12Z...WITH SLIGHTLY
HIGHER CHANCES AT KGSO/KINT AND KFAY BASED ON FORECAST SOUNDINGS.
HOWEVER..CONFIDENCE IN IFR OR LIFR CEILINGS IS STILL LOW AT THIS
TIME.
ADDITIONAL SHOWERS AND STORMS ARE EXPECTED TO DEVELOP BY THIS
AFTERNOON AS A THIS MORNINGS OUTFLOW AND A SURFACE TROUGH WILL
LIKELY SERVE AS A FOCUS FOR CONVECTION. WEAK STEERING FLOW AND THE
POTENTIAL FOR VARIOUS OUTFLOW BOUNDARIES MAKE IT DIFFICULT TO TIME
CONVECTION AT ANY SPECIFIC TAF SITE...BUT CONFIDENCE IS FAIRLY HIGH
THAT ANY TERMINAL COULD SEE A SHOWER OR STORM THIS AFTERNOON/EVENING.
OUTLOOK...AFTERNOON SHOWERS AND STORMS...AS WELL AS EARLY MORNING
STRATUS/FOG WILL BE POSSIBLE EACH DAY THIS WEEK. AN APPROACHING
COLD FRONT WILL LIKELY ENHANCE THE COVERAGE OF SHOWERS/STORMS LATE
THIS WEEKEND INTO EARLY NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BSD/WSS
NEAR TERM...BLS
SHORT TERM...BLS
LONG TERM...HARTFIELD
AVIATION...BLS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
150 AM EDT WED SEP 3 2014
.SYNOPSIS...A WEAK SURFACE FRONT WILL SETTLE SOUTHWARD ACROSS
CENTRAL NC TODAY. HIGH PRESSURE WILL BUILD BACK OVER THE AREA FOR
THE REMAINDER OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 PM TUESDAY...
CONVECTION HAS LARGELY DISSIPATED ACROSS THE AREA THIS EVENING WITH
NOCTURNAL STABILIZATION TAKING HOLD. HOWEVER... AN APPROACHING LINE
OF SHOWERS AND STORMS... CURRENTLY MOVING EAST-SOUTHEASTWARD THROUGH
THE NC AND VA MOUNTAINS... IN ADVANCE OF A WEAK COLD FRONT IS
EXPECTED TO APPROACH/POSSIBLY MOVE INTO PORTIONS OF THE AREA
OVERNIGHT. WITH THE SPC MESOPAGE STILL SHOWING 1000-2000 J/KG OF
MUCAPE ACROSS OUR NORTHWEST/NORTHERN PIEDMONT AND THE LATEST RAP AND
HRRR SHOWING THE POTENTIAL FOR SOME OF THIS ACTIVITY TO MOVE INTO
THIS AREA (NW/N PIEDMONT) WILL LEAVE A CHANCE OF SHOWERS AND STORMS
IN THE FORECAST FOR THIS AREA. HOWEVER.. WITH THE LACK OF GOOD DEEP
SHEAR AND DAYTIME HEATING THINK THIS LINE WILL CONTINUE TO SHOW A
WEAKENING TREND AS IT MOVES INTO NW/N PORTIONS OF CENTRAL NC AROUND
MIDNIGHT OR SHORTLY AFTER. THUS... WOULD EXPECT ANY OF THIS
WEAKENING LINE TO REMAIN BELOW SEVERE LIMITS.
WHERE HEAVY RAINFALL OCCURRED THIS PAST AFTERNOON-EVENING (GENERALLY
ALONG AND SOUTH OF A LINE FROM ASHEBORO TO RALEIGH TO WILSON) AND
SKIES PARTIALLY CLEAR OVERNIGHT... WE COULD SEE PATCHES OF FOG
DEVELOP DURING THE PRE-DAWN HOURS OF WEDNESDAY. MIN TEMPS NEAR 70-
LOWER 70S.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 335 PM TUESDAY...
SHEAR AXIS AND ATTENDANT SURFACE BOUNDARY WILL LIE ACROSS THE
SOUTHERN COUNTIES OF CENTRAL NC. ISOLATED SHOWERS AND STORMS ALONG
THIS FEATURE WEDNESDAY MORNING WILL GROW IN COVERAGE AS THE
ATMOSPHERE HEATS UP...LEADING TO GREATER LOW LEVEL INSTABILITY.
RELATIVELY WEAK STEERING FLOW SUGGEST THAT THE STORMS WILL BE SLOW
MOVING. IF STORMS OCCUR OVER URBAN LOCATIONS...THIS MAY LEAD TO
MINOR FLOODING OF STREETS AND POOR DRAINAGE AREAS.
PLAN TO CAP POPS AT 50 PERCENT ACROSS THE SOUTH...DWINDLING TO 25-35
PERCENT ACROSS THE NW.
MAX TEMPS WEDNESDAY DEPENDENT ON WHEN CONVECTIVE COVERAGE INCREASES
AND WHETHER ANY PERIODS OF PARTIAL SUN OCCUR. BETTING ON SOME
PARTIAL SUN INT HE LATE MORNING-EARLY AFTERNOON PRIOR TO CONVECTION
INCREASING AFTER 2-3 PM. IF SKIES REMAIN OVERCAST OR CONVECTION
BECOMES ACTIVE BY LUNCHTIME...MAX TEMPS MAY END UP BEING 5-6 DEGREES
COOLER. CONTINUED WARM AND MUGGY WEDNESDAY NIGHT WITH SCATTERED
CONVECTION SLOWLY DIMINISHING/DISSIPATING. MIN TEMPS NEAR 70-LOWER
70S.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS OF 255 PM TUESDAY...
FOR THU/FRI: CONTINUED WARM/HUMID WITH DAILY SCATTERED SHOWERS AND
STORMS. AT THE SURFACE... THE WEAK FRONTAL ZONE WILL LIKELY HAVE
WASHED OUT BY THU MORNING... AND THE SURFACE HIGH CENTERED OFF THE
SOUTHEAST COAST WILL INTRODUCE A MOIST CONFLUENT LOW LEVEL FLOW OFF
THE ATLANTIC INTO NC. A POSITIVELY TILTED TROUGH WILL SHIFT FROM
MT/DAKOTAS/SCENTRAL CANADA EARLY THU ACROSS ONT/QUE BY FRI NIGHT...
PROPELLING A COLD FRONT THROUGH THE GREAT LAKES/MID MISS VALLEY. AS
THE FLAT RIDGE HOLDS ACROSS THE SOUTHEAST/MIDSOUTH/GULF STATES
HOWEVER... WE`LL STAY WITHIN AN ENVIRONMENT CHARACTERIZED BY WEAK
SHEAR AND MODERATE INSTABILITY (TEMPERED BY WARM MID LEVELS). PW
VALUES SHOULD STAY ABOVE NORMAL AT 1.7-1.9"... NOT UNEXPECTED GIVEN
THE TROPICAL NATURE OF THE INCOMING AIR MASS... AND SUFFICIENT TO
SUPPORT SCATTERED CONVECTION ALONG THE SEA BREEZE... DYING FRONTAL
ZONE... OR ANY OTHER SUBTLE BOUNDARY. WILL RETAIN AFTERNOON AND
EVENING STORM CHANCES BOTH DAYS... WITH TEMPS HOLDING ABOUT A
CATEGORY ABOVE NORMAL AS THICKNESSES STAY AROUND 10 M ABOVE NORMAL.
FOR SAT-TUE: STILL EXPECT A TRANSITION FROM THE WARM/HUMID WEATHER
TO MORE SEASONABLE CONDITIONS LATE IN THE WEEKEND. THE INITIAL MID
LEVEL TROUGH OVER ERN QUEBEC WILL CONTINUE SHIFTING EAST OVER THE
MARITIMES... WHILE A STRONG SLUG OF STRONG VORTICITY EMANATING FROM
A STRONG COLD VORTEX OVER THE BEAUFORT SEA WILL PUSH EASTWARD CLOSE
ON ITS HEELS... CROSSING HUDSON BAY ON SUNDAY. THIS SHOULD PUSH THE
SURFACE COLD FRONT TO JUST NW OF NC BY SUN... AND WELL INTO THE
STATE BY EARLY MON. BOTH THE GFS AND ECMWF TRACK THEIR COOL PARENT
HIGHS OVER THE ST LAWRENCE VALLEY/SRN QUEBEC MON/TUE... WITH THE
COLD FRONT PUSHING TO ERN NC AND ACROSS NWRN SC. THIS MODEL
AGREEMENT LEADS TO GROWING CONFIDENCE THAT THE PARENT HIGH WILL BE
DENSE ENOUGH TO PUSH THIS COOLER AIR WELL INTO CENTRAL NC...
ALTHOUGH IT MAY NOT HAPPEN UNTIL LATE SUN NIGHT INTO MON MORNING.
WILL FOLLOW THIS TREND WITH TEMPS HOLDING ABOVE NORMAL SAT/SUN (BUT
NOT AS WARM IN THE NORTH SUN DUE TO MORE CLOUDS) WITH HIGHS IN THE
MID 80S TO NEAR 90... BUT THEN EXPECT TEMPS TO PLUNGE FOR MON/TUE
WITH THICKNESSES DROPPING TO 10-20 M BELOW NORMAL... YIELDING HIGHS
NEAR 80 TO LOWER 80S. REGARDING PRECIP CHANCES... WE`RE LIKELY TO
SEE SCATTERED TO PERHAPS NUMEROUS SHOWERS AND STORMS LATE SAT
THROUGH AT LEAST SUN NIGHT... BOTH ALONG THE PREFRONTAL PIEDMONT
TROUGH AND AHEAD OF AND WITH THE FRONT ITSELF. SHOWER/STORM CHANCES
ARE EXPECTED TO PEAK SUN AFTERNOON. WITH THE MID LEVEL TROUGH AXIS
SWINGING THROUGH THE REGION MON... WE MAY SEE LINGERING CHANCES FOR
RAIN ESPECIALLY SOUTH AND EAST. THE SURFACE RIDGE NOSING IN FROM THE
NORTH LATE MON INTO TUE ACCOMPANIED BY LOWERING PW VALUES SHOULD
MEAN MOSTLY DRY WEATHER TUE... AS THE MID LEVEL TROUGH AXIS LIFTS NE
AWAY FROM THE REGION FOLLOWED BY WEAK MID LEVEL SHORTWAVE RIDGING
OVER THE CAROLINAS. -GIH
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
AS OF 150 AM WEDNESDAY...
A LINE OF SHOWERS AND STORMS CROSSING THE MOUNTAINS HAS WEAKENED
DRAMATICALLY SINCE 04Z. OUTFLOW AHEAD OF THE DISSIPATING CONVECTION
MAY STILL TRIGGER A FEW ISOLATED SHOWERS EARLY THIS MORNING...WITH
HIRES MODELS SHOWING A FEW SHOWERS FROM KRDU NORTH BY 09Z.
MEANWHILE...PATCHY STRATUS WILL BE POSSIBLE BY 12Z...WITH SLIGHTLY
HIGHER CHANCES AT KGSO/KINT AND KFAY BASED ON FORECAST SOUNDINGS.
HOWEVER..CONFIDENCE IN IFR OR LIFR CEILINGS IS STILL LOW AT THIS
TIME.
ADDITIONAL SHOWERS AND STORMS ARE EXPECTED TO DEVELOP BY THIS
AFTERNOON AS A THIS MORNINGS OUTFLOW AND A SURFACE TROUGH WILL
LIKELY SERVE AS A FOCUS FOR CONVECTION. WEAK STEERING FLOW AND THE
POTENTIAL FOR VARIOUS OUTFLOW BOUNDARIES MAKE IT DIFFICULT TO TIME
CONVECTION AT ANY SPECIFIC TAF SITE...BUT CONFIDENCE IS FAIRLY HIGH
THAT ANY TERMINAL COULD SEE A SHOWER OR STORM THIS AFTERNOON/EVENING.
OUTLOOK...AFTERNOON SHOWERS AND STORMS...AS WELL AS EARLY MORNING
STRATUS/FOG WILL BE POSSIBLE EACH DAY THIS WEEK. AN APPROACHING
COLD FRONT WILL LIKELY ENHANCE THE COVERAGE OF SHOWERS/STORMS LATE
THIS WEEKEND INTO EARLY NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BSD/WSS
NEAR TERM...BSD/WSS
SHORT TERM...WSS
LONG TERM...HARTFIELD
AVIATION...BLS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
332 PM CDT WED SEP 3 2014
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 319 PM CDT WED SEP 3 2014
CONCERN REMAINS HOW FAR NORTH CONVECTION GETS INTO SOUTHEASTERN
FCST AREA LATE THIS AFTN/EVE AND HOW MUCH CONVECTION/PRECIP
DEVELOPS IN WRN ND THIS EVE AND MOVES EAST OVERNIGHT. RAP/HRRR AND
NAM12 HAVE BEEN DOING REASONABLE IN THEIR DEPICTION OF CONVECTION
IN CNTRL MN NORTH OF THE WARM FRONT. OBS INDICATE LIKELY WARM
FRONT FROM ABOUT WATERTOWN TO CANBY MN THEN TOWARD HUTCHINSON MN
THEN TO THE TWIN CITIES. IT HAS BEEN MOVING NORTHWARD. RAP SHOWS
LOW LEVEL JET FEEDING INTO BAND OF STORMS THAT HAS BEEN SLOWLY
LIFTING NORTHEAST THRU CNTRL MN TURNING A BIT MORE SOUTHWEST TO
NORTHEAST ORIENTATION AFTER 00Z AND THUS FOCUS OF PRECIP WILL
SHIFT EAST. REGIONAL RADARS SHOWING NOW SOME DEVELOPING SOUTHWEST
OF LINE INTO THE WARM SECTOR WEST OF WILMAR..THOUGH IT IS WEAK
NOW. IDEA FROM EARLIER SWOMCD IS FOR ACTIVITY TO INCREASE IN THE
AREA NORTHWEST AND WEST OF THE TWIN CITIES NEXT FEW HOURS. IT DOES
APPEAR MORE AND MORE LIKELY THAT ONLY THE FAR SOUTHEASTERN FCST
AREA WILL HAVE ANY IMPACTS FROM THESE STORMS AND THAT MOST WILL
STAY JUST SOUTHEAST OF OUR AREA. THUS TRIMMED POPS SOME BUT DID
KEEP SEVERE MENTION AT LEAST FOR NOW INTO THE EVE IN FAR
SOUTHEASTERN FCST AREA. REST OF THE AREA DRY THRU MID EVENING.
THEN WHAT HAPPENS IS IN QUESTION. RAP SHOWS A DEVELOPING LOW LEVEL
JET AND QUITE STRONG 850 THETA-E ADVECTION AND AN AREA OF
SHOWWALTERS TO -10C MOVING NORTH INTO SE ND 06Z AND JUST
AFTERWARDS. MAIN FORCING WILL BE MORE NORTHWEST TOWARD UPPER LOW
IN SOUTHEASTERN SASK. MODELS NOT EXCITED ABOUT TOO MUCH IN THIS
ELEVATED UNSTABLE LAYER AS IT MOVES INTO SE ND OVERNIGHT BUT AREA
IS IN FAVORABLE POSITION OF LOW LEVEL JET (LEFT QUAD) AND STRONG
INSTABILITY GRADIENT SO WOULDNT BE SUPRISED IF TSTMS DEVELOP
OVERNIGHT AHD OF COLD FRONT IN A MORE WIDESPREAD FASHION THAN
MODEL ADVERTISES.
ANYHOW....DID KEEP SEVERE MENTION OVERNIGHT PER DAY 1 SLIGHT RISK
OVER CNTRL INTO SE ND AND THIS CAN BE ADJUSTED AS NEEDED. IF 850
MB SHOWWALTERS AND LOW LEVEL JET ARE ACCURATE THEN WOULD BE ENOUGH
FOR SOME SEVERE HAILERS. MU CAPES INTHE 2500 J/KG RANGE IN SE ND.
LESS INSTABILITY FARTHER NORTH BUT MAYBE A BIT BETTER CHC OF A
BAND OF SHOWERS/STORMS LATE NIGHT INTO EARLY THURSDAY. PRECIP WILL
EXIT NW MN THURSDAY AFTN...THEN DRIER AND COOLER AIR MOVES IN THU
NIGHT. THOUGH SOME WRAPAROUND CLOUD COVER PSBL ESP IN NW MN.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 319 PM CDT WED SEP 3 2014
HIGH PRESSURE IN CONTROL FRIDAY WITH LIKELY DIURNAL CU WITH COOLER
AIR ALOFT.
FOR FRI NIGHT INTO TUESDAY...
A NORTHWEST FLOW PATTERN ALOFT...VOID OF ANY APPRECIABLE MOISTURE
TRANSPORT INTO THE AREA...WILL KEEP A DRY AND COOL AIR MASS IN PLACE
THROUGH THE UPCOMING WEEKEND. THE UPPER AIR PATTERN BECOMES ZONAL
SUNDAY AND TURNS TO THE SOUTHWEST SUNDAY NIGHT...WITH LEE SIDE LOW
PRESSURE MOVING INTO THE PLAINS ON MONDAY. THIS WILL OPEN UP THE
GULF FOR INCREASED MOISTURE TRANSPORT INTO THE AREA AND BRING MORE
ACTIVE WEATHER FOR THE EARLY TO MIDDLE PART OF NEXT WEEK.
TEMPERATURES WILL TYPICALLY BE RIGHT AT OR SLIGHTLY COOLER THAN
SEASONAL NORMS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 113 PM CDT WED SEP 3 2014
VFR CONDS WILL CONTINUE THROUGH THE DAY AND INTO THE LATE
EVENING. THUNDERSTORMS ARE THEN EXPECTED TO SPREAD ACROSS THE AREA
BY EARLY THU MORNING...WITH CIGS GENERALLY REMAINING VFR EXCEPT IN
VCNTY OF TSTMS. WILL KEEP VCTS IN ALL TAF SITES.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...RIDDLE
LONG TERM... RIDDLE/SPEICHER
AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1011 AM CDT WED SEP 3 2014
.UPDATE...
ISSUED AT 1001 AM CDT WED SEP 3 2014
MAIN FOCUS REMAINS ON WHAT WILL HAPPEN LATER TODAY IN TERMS OF
SEVERE CONVECTION IN FAR NORTHEASTERN SD..WEST CENTRAL-CENTRAL MN
AND HOW FAR NORTH WILL IT REACH. INCOMING 12Z DATA FROM NAM AND
LATEST RAP/HRRR MODELS INDICATE ABOUT THE SAME SCENERIO WITH
EVENTUAL NORTHWARD ADVANCE OF CONVECTION ZONE THAT IS NOW FROM
BTWN BROOKINGS AND WATERTOWN SD TOWARD THE TWIN CITIES...WITH IT
REACHING NEAR THE SISSETON-ALEXANDRIA-LONG PRAIRIE MN LINE EARLY
TO MID AFTERNOON. HOWEVER HRRR MAY BE A TAD FAST IN SPREADING IT
NORTH AS ABUNDANCE OF CLOUD COVER MAY KEEP TRUE WARM FRONT A BIT
SOUTH YET OF PROGGED POSITION...WHICH FROM THE HRRR IS ROUGHLY NR
A WATERTOWN-WILMAR LINE AT 21Z. REGARDLESS...MAIN THREAT FOR ANY
PRECIP NOT REACHING THE FAR SOUTHEASTERN FCST TIL THIS AFTN WITH
INCREASING CHANCES BY LATE AFTN. RISK OF SEVERE THERE...THOUGH
HIGHEST SEVERE PARAMETERS REMAIN A TAD SOUTH. OTHERWISE DRY OVER
MUCH OF NW MN INTO ERN ND (OUTSIDE OF FAR SOUTHEASTERN CORNER).
MAIN UPPER LOW TO LIVE EAST-NORTHEAST WITH CONVECTION DEVELOPING
ALONG FRONT THIS EVENING IN FAR WESTERN ND AND THEN SOME CHANCE OF
A COMPLEX MOVING EAST INTO ERN ND OVERNIGHT. LATEST RAP SHOWS
QUITE IMPRESSIVE SHOWALTERS DOWN TO -10C 06Z-07Z INTO SE ND IN THE
LEFT QUAD OF A 40-45 KT LOW LEVEL JET OVER EASTERN SD. SO IN THAT
RESPECT MODELS MAYBE UNDERESTIMATING PRECIP TONIGHT.
AFTER COORD WITH WFO BIS....ONLY REAL CHANGE TO FCST IS TO REMOVE
THAT BLENDED POP ZONE IN DEVILS LAKE REGION WE HAD LATE THIS AFTN.
NOTHING THERE TIL PAST 00Z.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 315 AM CDT WED SEP 3 2014
CONVECTION CHANCES...SEVERITY...AND TIMING WILL BE THE HEADACHES
FOR THE SHORT TERM.
STRONG SHORTWAVE TROUGH CURRENTLY DIGGING INTO THE PAC NW WILL
QUICKLY MOVE INTO MT DURING THE DAY TODAY. SFC LOW PRESSURE OVER
MT/WY WILL MOVE INTO THE DAKTOAS BY THIS AFTERNOON. CONVECTION FIRING
ALONG THE NOSE OF THE LOW LEVEL JET OVER EASTERN SOUTH DAKOTA WILL
CONTINUE NORTHEASTWARD AND MAY CLIP PART OF GRANT COUNTY LATER
THIS MORNING. THUS...KEPT SOME LOW POPS GOING FOR THIS MORNING BUT
THINK THE BETTER PRECIP CHANCES WILL HOLD OFF UNTIL LATER THIS
AFTERNOON AS THE SFC LOW COMES EAST AND A WARM FRONT LIFTS INTO
OUR FAR SOUTHERN COUNTIES. MODELS BRING UP QUITE A LOT OF MOISTURE
WITH THE FRONT...WITH THE NAM SHOWING LOW 70S DEW POINTS IN OUR
FAR SOUTH BY AFTERNOON. HOWEVER...GIVEN THE CURRENT READINGS OVER
NEB THINK THAT THE ECMWF/GFS WITH DEW POINTS IN THE 60S WILL BE
MORE IN LINE WITH REALITY. WITH WINDS ALOFT INCREASING AHEAD OF
THE SHORTWAVE BULK SHEAR VALUES WILL BE PUSHING 50 KTS BY THIS
AFTERNOON. SEVERE WEATHER WILL BE A POSSIBILITY...PARTICULARLY IN
THE LOW LEVEL SHEAR AREA NEAR THE WARM FRONT.
TONIGHT...THE SHORTWAVE TROUGH WILL MOVE INTO WESTERN ND...WITH
THE SFC LOW ENTERING THE EASTERN DAKOTAS. THERE WILL BE SOME GOOD
FRONTOGENESIS IN NORTHEASTERN SD AND OUR FAR SOUTHERN COUNTIES AS
THE SFC LOW PUSHES EAST. GFS/NAM BREAK OUT PRECIP OVER THE
SISSETON HILLS REGION INTO OUR SOUTHERN COUNTIES BUT THE ECMWF AND
GEM ARE DRIER. WARM MID LEVEL TEMPS MAY KEEP A LID ON CONVECTION
BUT THINK THAT THERE IS ENOUGH CHANCE FOR STORMS ALONG THAT
SOUTHERN SFC LOW CENTER THAT CONTINUED TO KEEP SOME CHANCE POPS
GOING. FURTHER NORTH...THE MAIN SHORTWAVE WILL BE MOVING INTO
SOUTHERN CANADA AND THE MODELS SHOW SOME HEAVY QPF ALONG THE
DEFORMATION ZONE TO THE NORTHWEST OF A NORTHERN LOW CENTER
DEVELOPING ALONG THE CANADIAN BORDER. CONTINUED TO KEEP HIGH POPS
GOING FOR THE NORTH IN AREAS THAT WILL BE CLOSER TO THE MAIN
UPPER SHORTWAVE. CENTRAL COUNTIES WILL SEE LESSER CHANCES THAN THE
FAR NORTH AND FAR SOUTH...BUT KEPT SOME SLIGHT POPS.
THURSDAY...THE MAIN SHORTWAVE WILL MOVE OFF INTO SOUTHERN
CANADA...WITH THE SFC LOW MOVING INTO THE GREAT LAKES. THERE WILL
BE SOME GOOD ISENTROPIC DOWNGLIDE MOVING INTO OUR WESTERN COUNTIES
AND THEN ACROSS THE CWA FROM MID MORNING INTO THE AFTERNOON. THERE
COULD BE SOME WRAP AROUND PRECIP IN THE NORTH...BUT MODELS ARE
SHOWING A TREND OF A DRY SLOT COMING IN FOR MUCH OF THE CWA. WINDS
WILL BE A GREATER CONCERN WITH STRONG COLD AIR ADVECTION AND A
TIGHT PRESSURE GRADIENT. CONTINUED TO KEEP SPEEDS BELOW ADVISORY
CRITERIA FOR NOW BUT WILL MONITOR. THE NORTHWEST WINDS WILL BRING
IN SOME COOLER AIR AND OUR NORTHWESTERN COUNTIES COULD STAY IN THE
LOW 60S WHILE THE SOUTHEAST WILL BE WARMER WITH A LATER FRONTAL
PASSAGE.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 315 AM CDT WED SEP 3 2014
THURSDAY NIGHT THROUGH FRIDAY NIGHT...SOME LINGERING SHOWERS WILL
BE POSSIBLE THURSDAY NIGHT AS THE SFC LOW PULLS AWAY INTO THE
GREAT LAKES. TEMPS SHOULD BE FAIRLY CHILLY IN THE 40S AS CLOUDS
BEGIN TO CLEAR OUT AND HIGH PRESSURE BUILDS INTO THE PLAINS. WEST
TO SOUTHWESTERLY WINDS WILL BRING IN SOME SLIGHTLY WARMER AIR FOR
FRIDAY WHICH WILL HELP KEEP TEMPS IN THE UPPER 60S...BUT ANOTHER
REINFORCING SHORT WAVE WILL BE DIGGING INTO THE PLAINS FRIDAY AND
FRIDAY NIGHT AND BRING DOWN ANOTHER FRONTAL BOUNDARY. A FEW OF THE
MODELS BREAK OUT SOME PRECIP WITH THIS REINFORCING FRONT...BUT
THINK THAT THERE WILL NOT BE MUCH MOISTURE AVAILABLE SO KEPT THE
FORECAST DRY FOR NOW. TEMPS FRIDAY NIGHT WILL BE MODERATED BY
CLOUD COVER BUT WILL STILL BE MAINLY IN THE 40S THANKS TO COLD AIR
ADVECTION.
SATURDAY THROUGH TUESDAY...PERIOD STARTS WITH A NORTHWEST FLOW AND
ENDS WITH THE NEXT SIGNIFICANT UPPER WAVE. FOR THE FIRST HALF OF
THIS PERIOD...INTO SUNDAY... THE WEATHER SHOULD BE PRECIPITATION
FREE. TIMING OF PRECIPITATION BECOMES PROBLEMATIC MONDAY AND
TUESDAY...AS RAW MODEL QPF IS PRETTY SCANT INTO 12Z MONDAY.
HOWEVER...WITH INCREASING SOUTHWEST FLOW ALOFT AND LOW - MID LEVEL
WAA AND INCREASINGLY COUPLED 200 MB JET STRUCTURE ARGUES FOR BROAD
LIFT. WITH THE GUIDANCE SUGGESTING ANOMALOUSLY HIGH...FOR
SEPTEMBER...TD AND PWATS APPROACHING +2 SIGMA CANNOT ARGUE AGAINST
BLENDED POPS. OVERALL TEMPERATURES AS FORECAST ARE PRETTY CLOSE TO
EARLY SEPTEMBER MEDIAN VALUES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 641 AM CDT WED SEP 3 2014
PATCHY FOG HAS IMPACTED KTVF AND KGFK AT TIMES THIS
MORNING...GOING RAPIDLY UP AND DOWN IN VIS. INCLUDED TEMPO GROUP
AT KGFK TO ACCOUNT FOR PATCHY FOG BUT THINK THAT ALL SITES WILL
SEE FOG DISSIPATE BY 13 OR 14Z. VFR CONDITIONS WILL CONTINUE FOR
MUCH OF THE PERIOD WITH EAST WINDS AROUND 10 KTS. WARM FRONT
MOVING IN FROM THE SOUTH MAY BRING SOME STORMS NEAR THE KFAR
AREA...AND THERE WILL BE ANOTHER ROUND OF STORMS POSSIBLE AFTER
06Z IN THE NORTHERN TAF SITES. JUST INCLUDED VCTS MENTION AT
KFAR...KDVL...AND KGFK FOR NOW. THERE COULD BE SOME MVFR CIGS LATE
IN THE PERIOD WITH MORE MOISTURE IN THE REGION...BUT JUST INCLUDED
THE LOWER CIGS AT KDVL AND KBJI FOR NOW.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...RIDDLE
SHORT TERM...JR
LONG TERM...JR/EWENS
AVIATION...JR
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
802 PM EDT THU SEP 4 2014
.SYNOPSIS...
A LOW WILL MOVE ACROSS ONTARIO TONIGHT AND INTO QUEBEC FRIDAY AND
FRIDAY NIGHT. A COLD FRONT ASSOCIATED WITH THE LOW WILL MOVE
ACROSS THE AREA FRIDAY NIGHT. A RIDGE WILL BUILD IN SATURDAY NIGHT
AND LAST INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
RADAR RETURNS GETTING AWFULLY CLOSE TO KTOL. THIS ACTIVITY SHOULD
DISSIPATE AFTER SUNSET BUT HAVE ADDED A SMALL MENTION TO LUCAS CO.
MADE THE SKY FORECAST MORE OPTIMISTIC FOR EASTERN AREAS.
PREVIOUS...THE CUMULUS WILL DISSIPATE QUICKLY. SOME MID AND HIGH CLOUDS
WILL BE AROUND. PARTLY CLOUDY SHOULD HANDLE IT. WENT TOWARD THE
WARMER GUIDANCE FOR LOWS BECAUSE OF THE DEW POINTS AND SOME WIND.
THE HRRR MODEL TRIES TO BRING SOME SPRINKLES OR SHOWERS INTO NW OH
BY EVENING...THIS IS THE REMNANTS OF THE SYSTEM FROM EARLIER. THIS
AREA IS DECREASING...WILL KEEP IT DRY.
THE NAM ESPECIALLY TRIES TO HINT AT SOME SHOWERS DEVELOPING OVER
NORTHWEST OHIO TOWARD DAYBREAK FRIDAY. THE GFS KIND OF HINTS AT THAT
TOO. AT THIS TIME KEEPING LATE TONIGHT DRY. THE NEXT SHIFTS WILL
HAVE TO MONITOR THIS.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY NIGHT/...
A WEAK UPPER TROF WILL MOVE THROUGH IN THE MORNING...THIS MAY CAUSE
AN ISOLATED SHOWER OR SPRINKLE. THE BEST CHANCE WILL BE LATER IN THE
AFTERNOON AND EVENING AS THE COLD FRONT MOVES IN. THE BEST CHANCE
EXCEPT FOR NW OH WILL BE MAINLY AFTER MIDNIGHT AS MORE MOISTURE
COMES IN. SHOWERS AND THUNDERSTORMS WILL BEGIN DECREASING FROM THE
NORTH BY DAYBREAK AND THE DRYING SHOULD BE SOMEWHAT QUICK.
THE PRECIPITABLE WATER WILL BE AROUND 2 INCHES FRIDAY NIGHT. SOME OF
THE THUNDERSTORMS COULD BE STRONG WITH LOCALLY HEAVY RAIN. THE BEST
THREAT OF SEVERE WOULD BE OVER NORTHWEST OHIO IN THE EVENING AND
SEVERE WOULD BE ISOLATED AND VERY MARGINAL.
THE LAKE AND 850 MB TEMPERATURE DIFFERENCE BY SUNDAY MORNING WILL BE
NEAR 13C. SOME LAKE EFFECT CLOUDS WILL BE LIKELY. NOT EXPECTING ANY
SHOWERS BECAUSE OF SO MUCH RIDGING.
USED A BLEND OF GUIDANCE FOR THE TEMPERATURE FORECAST.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL BE LOCATED OVER NEW ENGLAND ON MONDAY...BUILDING
OFFSHORE ON MONDAY NIGHT. SOUTHEASTERLY RETURN FLOW BEHIND THE
DEPARTING HIGH WILL LEAD TO A GRADUAL INCREASE IN LOW LEVEL MOISTURE
FROM THE SOUTHEAST. BY TUESDAY WE SEE THE FIRST IN A SERIES OF
SHORTWAVES APPROACH THE OHIO VALLEY AND INTERACT WITH THIS MOISTURE
TO CAUSE A CHANCE OF SHOWERS AND THUNDERSTORMS. LONG RANGE MODELS
ARE STRUGGLING TO RESOLVE THESE SHORTWAVES AS WE TRANSITION FROM A
MORE ZONAL UPPER LEVEL FLOW OVER THE WEEKEND TO A BROAD TROUGH
THROUGH MIDWEEK. ADDED A CHANCE OF THUNDERSTORMS TO THE FORECAST ON
TUESDAY AND WILL LEAVE POPS IN THROUGH MIDWEEK WITH THE UNSETTLED
PATTERN SETTING UP. TEMPERATURES WILL BE TRICKY AND DEPEND ON
COVERAGE OF CLOUDS AND SHOWERS. TEMPERATURES START THE LONG TERM OFF
NEAR TO SLIGHTLY BELOW NORMAL...TRENDING COOLER TOWARDS DAY 7.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
A FEW THUNDERSTORMS WERE LOCATED OVER NORTHWEST OHIO ALONG OUTFLOW
BOUNDARIES FROM EARLIER CONVECTION. THESE STORMS SHOULD NOT LAST
ALL THAT LONG WITH THE SETTING SUN...MAYBE UNTIL 02Z. AFTER THE
THUNDER ENDS THERE WILL BE SOME CONVECTIVE DEBRIS CLOUDINESS. IT
APPEARS THERE WILL BE ENOUGH WIND...GREATER THAN 5 KNOTS...AT MOST
LOCATIONS TO AVOID ANY MORNING.
WINDS WILL BECOME GUSTY BY FRIDAY AFTERNOON BUT SHOULD NOT EXCEED
20 KNOTS. AFTERNOON THUNDER WILL BE POSSIBLE ACROSS NW OHIO BUT
THE MAIN SHOW WILL BE AFTER 00Z.
OUTLOOK...NON VFR LIKELY IN SHOWERS AND THUNDERSTORMS FRIDAY
NIGHT AND CONTINUING ON SATURDAY WITH SHOWERS ASSOCIATED WITH THE
COLD FRONT.
&&
.MARINE...
WINDS WILL REMAIN OUT OF THE SOUTH OVERNIGHT WITH SOUTHWEST WINDS
INCREASING TO 10 TO 15 KNOTS ON FRIDAY AHEAD OF AN APPROACHING COLD
FRONT. THE FRONT WILL PUSH SOUTH ACROSS THE AREA ON FRIDAY NIGHT
WITH WINDS SHIFTING TO THE NORTH BY EARLY SATURDAY. WAVES WILL
INCREASE TO 2 TO 3 FEET WITH THE NORTHERLY FLOW ON SATURDAY. HIGH
PRESSURE WILL BUILD EAST ACROSS THE GREAT LAKES FROM SATURDAY NIGHT
THROUGH MONDAY WITH GENERALLY LIGHT WINDS AND WAVE CONDITIONS.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KIELTYKA
NEAR TERM...KIELTYKA
SHORT TERM...KIELTYKA
LONG TERM...KEC
AVIATION...MULLEN
MARINE...KEC
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
742 PM EDT THU SEP 4 2014
.SYNOPSIS...
WEAK HIGH PRESSURE SLIDES EAST WITH INCREASING MOISTURE THROUGH
FRIDAY. COLD FRONT MOVES ACROSS SATURDAY AFTERNOON. FRONT SLOWS
DOWN AS IT CREEPS SOUTH OF AREA. WEAK HIGH PRESSURE SUNDAY AFTERNOON.
&&
.NEAR TERM /THROUGH FRIDAY/...
INCREASED POPS TO LIKELY PER LATEST RADAR IMAGES SHOWING SCATTERED
TO NUMEROUS SHOWERS WITH EMBEDDED THUNDERSTORMS AFFECTING THE
WESTERN SLOPES AND PORTIONS OF THE SOUTHERN COAL FIELDS THIS
AFTERNOON. THE STRONGER STORMS COULD PRODUCE 1 TO 2 INCHES PER
HOUR. WILL CONTINUE MONITORING RADAR TRENDS LOOKING FOR REPETITIVE
SHOWERS THAT COULD PRODUCE MINOR WATER PROBLEMS. RAINFALL ACTIVITY
SHOULD DIMINISH IN INTENSITY AND COVERAGE LATER THIS EVENING.
PREVIOUS DISCUSSION BELOW...
HIGH PRESSURE...OFF TO THE EAST...HAS ALLOWED FOR WARM AND MUGGY
WEATHER ACROSS THE REGION...WITH DEW POINTS ACROSS MUCH OF THE AREA
THIS AFTERNOON IN THE MID 60S TO LOWER 70S. SATELLITE PW ESTIMATES
AROUND 1.2 TO 1.4 INCHES ACROSS MUCH OF SOUTHWEST VA...WEST VA...AND
EASTERN KY...WITH LOWER PWS OF AROUND AN INCH ACROSS SOUTHEAST OHIO.
WITH THE LIGHT SOUTHERLY FLOW...AND THE HUMID UNSTABLE AIRMASS IN
PLACE...HAVE STARTED TO SEE CONVECTION FIRE OFF...PARTICULARLY
ACROSS WV/ERN KY/SW VA. MUCH OF THIS CONVECTION SHOULD DIE OFF AFTER
SUNSET...BUT WITH THE LIGHT FLOW...AND HUMID AIRMASS IN
PLACE...EXPECT LOCALIZED DOWNPOURS. 1 HOUR FFG AT THIS POINT IS
GENERALLY 1.6 INCHES OR GREATER...SO NOT TOO CONCERNED ABOUT WATER
ISSUES...BUT LOCALIZED ISSUES...PARTICULARLY IN LOW LYING
SPOTS...CANNOT BE RULED OUT. MAINLY FOLLOWED THE HRRR MODEL FOR
CONVECTION THIS AFTERNOON...AND INCREASED POPS FROM PREVIOUS
FORECAST.
MUCH OF THE ACTIVITY WILL WANE OVERNIGHT. COULD BE MORE FOG
FORMATION THAN CURRENTLY FORECAST FOR TONIGHT. THIS WILL DEPEND ON
HOW MUCH CLEARING IS ABLE TO OCCUR...AND LOCATIONS OF RAINFALL THIS
AFTERNOON. A WEAK UPPER DISTURBANCE IS EXPECTED TO MOVE NORTHEAST
THROUGH THE CWA TONIGHT AND ON FRIDAY...WHICH COULD HELP PROVIDE
ENOUGH CLOUD COVER TO KEEP MUCH OF THE FOG FORMATION AT BAY.
SHOWERS AND THUNDERSTORMS WILL INCREASE IN COVERAGE AGAIN ON FRIDAY
AS THE WEAK DISTURBANCE MOVES THROUGH THE REGION...COMBINED WITH
DAYTIME HEATING. COLD FRONT WILL BEGIN TO APPROACH THE AREA TOWARDS
THE END OF THE PERIOD...GENERALLY ACROSS NW OHIO/NORTHERN IN BY END
OF PERIOD. DUE TO THE TIMING OF THE FRONT...SEVERE IS NOT EXPECTED
ON FRIDAY...BUT HEAVY DOWNPOURS WILL CONTINUE TO BE POSSIBLE.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
WE SEEM TO BE BOTTOM FEEDERS LATELY. LIFE AT THE BOTTOM OF THE
WESTERLIES CONTINUES DURING THIS TIME FRAME...WITH ANOTHER FRONT
TRYING TO SINK SOUTH SATURDAY...BUT THEN STRUGGLING TO MOVE SOUTH
OF OUR FORECAST AREA SATURDAY NIGHT INTO SUNDAY MORNING.
NO MAJOR CHANGES TO THE MAIN "BISCUIT" ON SATURDAY INTO SATURDAY
EVENING.
BACK TO FRIDAY NIGHT. STILL WANT TO KEEP MOST OF THE LOWLANDS DRY
FOR THE EVENING HOURS. HAD THE 20 AND 30 POPS FROM THE AFTERNOON
WANING OVER THE MOUNTAIN COUNTIES 00Z TO 03Z. HAVE CHANCE POPS
INCREASING 04Z TO 10Z SATURDAY IN SOUTHEAST OHIO...AHEAD OF THE NEXT
FRONT AND APPROACHING MID LEVEL DISTURBANCES IN THE BASE OF THE
WESTERLY FLOW IN THE MIDWEST.
STILL HAVE OUR LIKELY POPS MOVING SE ACROSS CWA DURING THE 12Z
SATURDAY TO 00Z SUNDAY TIME FRAME. COULD EASILY SEE BAND OF
CONVECTION WELL AHEAD OF THE FRONT...THEN A SMALLER BAND NEAR THE
FRONT LATER SATURDAY AFTERNOON INTO SATURDAY EVENING. COULD EASILY
SEE 2000+ J/KG CAPE DEVELOP ESPECIALLY CKB-HTS ON E AND SE BY
AFTERNOON. YET...STEERING WIND FLOW FROM 12Z MODELS ABOUT 25 TO 30
KNOTS...NOT TOO FAST...NOT TOO SLOW.
DID TRY TO INCREASE MAX TEMPERATURE A BIT FROM EKN-CRW ON SE ON
SATURDAY...FIGURING THE HIGHER POPS DO NOT ARRIVE UNTIL THE AFTERNOON
HOURS. ALSO TRIED TO HAVE THAT MAXIMUM TEMPERATURE AROUND MIDDAY
SATURDAY WITH TEMPERATURES MODIFIED BY CONVECTION DURING THE MID AND
LATE AFTERNOON.
THIS FRONT EXPECTED TO CREEP THROUGH...BUT LOW LEVEL WINDS AGAIN
VEER QUICKLY FROM NORTH TO EAST...RESULTING IN HOLDING UP THE DRYING
IN SOUTHERN WEST VIRGINIA AND SOUTHWEST VIRGINIA ON SUNDAY. MAIN
DRYING IN THE NORTH AND WESTERN COUNTIES. DIFFICULT TO FIGURE
WHEN...OR IF...THE CLOUDS IN THE SOUTH WILL BREAK SUNDAY AFTERNOON.
SO KEPT MAXIMUM TEMPERATURES DOWN ACROSS THE SOUTHERN WV COAL FIELDS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
USED WPC THINKING WITH SOME TWEAKS. WEAK SURFACE HIGH PRESSURE
WILL BE IN CONTROL ACROSS THE REGION SUNDAY NIGHT INTO MONDAY
NIGHT. A WARM FRONT WILL THEN LIFT NORTH TUESDAY...WITH A COLD
FRONT PUSHING EAST ON THURSDAY.
WPC TEMPS LOOKED GOOD AND WERE GENERALLY USED.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
EXPECT DIURNAL CONVECTION TO DISSIPATE AROUND SUNSET BECOMING JUST
LIGHT RAIN AND LOW CLOUDS. SKIES ACROSS MOST OF SOUTHEAST OH AND
WV SHOULD CLEAR BY MIDNIGHT...WITH SOME LOW CLOUDS REMAINING OVER
THE EASTERN MOUNTAINS.
HIGH PRESSURE TO PRODUCE CALM FLOW...AND MOSTLY CLEAR SKIES
OVERNIGHT. HOWEVER...PLENTY OF LOW LEVEL MOISTURE REMAINS IN PLACE
THROUGH FRIDAY. EXPECT AREAS OF DENSE POST RAIN FOG...AND
RADIATION FOG DEVELOPING MAINLY ALONG RIVER VALLEYS AND AREAS
THAT RECEIVED RAIN DURING THE LAST 12 HOURS. CONDITIONS COULD
DETERIORATE AFTER 06Z ACROSS THE LOWLANDS SITES...AND AFTER 09Z
MOUNTAIN SITES. OTHERWISE...MVFR CONDITIONS EXPECTED IN LOW
STRATUS OR LIGHT FOG.
ANY FOG WILL LIFT AFTER 13Z FOR A RETURN OF VFR CONDITIONS AREA
WIDE.
CONVECTION WILL REFIRE ACROSS AREA...PARTICULARLY WV/SOUTHWEST
VA/ERN KY AGAIN AFTER 16Z FRIDAY.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SATURDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: EXTENT AND DEPTH OF FOG FORMATION TONIGHT
MAY VARY FROM FORECAST.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE FRI 09/05/14
UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11
EDT 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
CRW CONSISTENCY H H H H H M L L L L L L
HTS CONSISTENCY H H H H H M H H H L L L
BKW CONSISTENCY H H H H H H H H H H H L
EKN CONSISTENCY H H H H H H L L L L L L
PKB CONSISTENCY H H H H H M H H H L L L
CKB CONSISTENCY H H H H H M M H H L L L
AFTER 00Z SATURDAY...
IFR POSSIBLE IN SHOWERS AND THUNDERSTORMS SATURDAY. IFR FOG
POSSIBLE SUNDAY MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JSH/KTB/SL
NEAR TERM...ARJ/SL
SHORT TERM...KTB
LONG TERM...JSH
AVIATION...ARJ
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1231 AM EDT WED SEP 3 2014
.SYNOPSIS...
HIGH PRESSURE WILL BUILD NORTHEAST UP THE APPALACHIAN MOUNTAINS
THROUGH WEDNESDAY NIGHT AND OFF THE EAST COAST BY THURSDAY NIGHT. A
WARM FRONT WILL LIFT NORTHEAST ACROSS THE AREA THURSDAY FOLLOWED BY
A COLD FRONT FRIDAY EVENING. HIGH PRESSURE WILL BUILD SOUTHEAST
ACROSS THE REGION INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
CONVECTION WITH DIFFUSE COLD FRONT NOW REDUCED TO 3 SMALL CLUSTERS.
VERY LITTLE LIGHTNING OCCURRING. RUC HANGS ON TO A FEW CELLS THRU
THE NIGHT SO WILL SLOW POP DROP OFF ENOUGH TO KEEP SLIGHT CHANCE
GOING LONGER INTO THE NIGHT.
MUCH OF THE CLOUD COVER FROM EARLIER IN THE DAY HAS DISSIPATED
LEAVING PATCHY LOWER CLOUDS WITH BAND OF JET INDUCED CIRRUS ABOVE.
WEAK COLD ADVECTION LOOKS EVEN MORE LIKELY TO NOT BE STRONG ENOUGH
TO BRING IN THE DRIER AIR AS QUICK AS THOUGHT EARLIER SO WILL INCH
LOWS UP EVEN ANOTHER DEG OVER THE SE 2/3 OF THE AREA.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/...
BROAD UPPER LEVEL TROUGH WILL MOVE EAST OF THE AREA OVERNIGHT
SETTING UP A ZONAL FLOW ACROSS THE COUNTRY ONCE AGAIN. SURFACE HIGH
WILL BUILD NORTHEAST AND THEN EAST OF THE AREA BY WEDNESDAY NIGHT.
WARM AIR ADVECTION WILL RESUME ON THURSDAY WITH A PRETTY GOOD SURGE
OF WARM AIR RACING NORTHEAST INTO THE FORECAST AREA. 850 MB
TEMPERATURES RISE FROM 16C WEDNESDAY NIGHT TO 20C BY FRIDAY.
INCREASED DEW POINT AIR WILL RETURN AND BRING WITH IT HIGHER
HUMIDITY ON FRIDAY.
COLD FRONT IS EXPECTED TO MOVE EAST ACROSS THE REGION FRIDAY
EVENING. CONVECTION IS EXPECTED TO REMAIN ASSOCIATED WITH THE COLD
FRONT FRIDAY AFTERNOON INTO FRIDAY NIGHT. OTHERWISE...NO MAJOR
THREAT FOR SHOWERS AND THUNDERSTORMS THROUGH THE EXTENDED PERIOD
UNTIL FRIDAY AFTERNOON. WILL HAVE TO KEEP AN EYE ON THE COLD FRONT
FRIDAY FOR SEVERE POTENTIAL DUE TO IDEAL TIMING IN THE HEAT OF THE
DAY.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
A SURFACE COLD FRONT WILL BE JUST ABOUT OUT OF THE AREA AT DAYBREAK
SATURDAY. THERE COULD BE A FEW SHOWERS ALONG AND BEHIND THE FRONT
BUT RAPID DRYING WILL OCCUR DURING THE AFTERNOON. READINGS NEXT
WEEKEND WILL BE BACK BELOW NORMAL WITH LOWS MONDAY MORNING POSSIBLY
GETTING INTO THE 40S. SUNDAY WILL BE A PLEASANT DAY WITH ABUNDANT
SUNSHINE. THE FALL LIKE WEATHER WILL CONTINUE ON MONDAY. THE
SURFACE HIGH RESPONSIBLE FOR THE QUIET WEATHER WILL EVENTUALLY MOVE
OFF TO THE EAST ON TUESDAY ALLOWING WARMER SOUTHERLY FLOW TO
RETURN. EXPECT TEMPS TUESDAY TO AVERAGE NEAR NORMAL. PRECIP
CHANCES SHOULD HOLD OFF TILL JUST AFTER THE PERIOD ENDS.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
HIGH PRESSURE WILL BUILD IN TODAY BEHIND A COLD FRONT THAT WILL BE
SOUTH OF THE AREA. MAIN CONCERN IS FOR EARLY OVERNIGHT/EARLY
MORNING FOG AND LOW STRATUS DEVELOPING ACROSS THE AREA. AMPLE LOW
LEVEL MOISTURE...DRYING ALOFT...AND LIGHT WINDS SHOULD ALLOW THE
FOR TO DEVELOP WITH WIDESPREAD MVFR/IFR RESTRICTIONS DEVELOPING
BEFORE DAYBREAK. AFTER FOG LIFTS EXPECT VFR CONDITIONS THROUGH THE
DAY. NEAR LAKE ERIE...KCLE AND KERI...EXPECT LAKE BREEZE TO
DEVELOP IN WEAK GRADIENT.
OUTLOOK...NON VFR LIKELY IN SHOWERS AND THUNDERSTORMS BY FRIDAY
EVENING INTO SATURDAY WITH THE NEXT COLD FRONT.
&&
.MARINE...
A SURFACE COLD FRONT WILL MOVE EAST OF THE LAKE BY EARLY THIS
EVENING. LINGERING SHOWERS OVER THE LAKE WILL ALSO BE GONE BY THAT
TIME. EXPECT THE FLOW TO BECOME WESTERLY BEHIND THE FRONT AND THEN
LIGHT AND VARIABLE OVERNIGHT. LIGHT FLOW WILL THEN CONTINUE
WEDNESDAY WITH SOUTHERLY FLOW DEVELOPING ON THURSDAY AS A SURFACE
RIDGE PUSHES EAST OF THE LAKE. SOUTH TO SOUTHWEST FLOW WILL THEN
GRADUALLY INCREASE AHEAD OF A COLD FRONT THAT WILL DROP SOUTH ACROSS
THE LAKE EARLY SATURDAY. MORE PRECIP IS LIKELY WITH THIS FRONT WITH
THE FLOW BECOMING NORTH BEHIND IT. DO NOT THINK SPEEDS WILL BE
STRONG ENOUGH FOR SMALL CRAFT HEADLINES. NORTHERLY FLOW WILL
CONTINUE THROUGH SUNDAY. SPEEDS MOST IF NOT THE ENTIRE PERIOD WILL
BE UNDER 15 KNOTS.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LOMBARDY
NEAR TERM...LOMBARDY
SHORT TERM...LOMBARDY
LONG TERM...KUBINA
AVIATION...TK
MARINE...KUBINA
AREA FORECAST DISCUSSION
NWS TULSA OK
604 PM CDT WED SEP 3 2014
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
VFR CONDITIONS ARE EXPECTED THROUGH THE ENTIRE TAF PERIOD
AT ALL SITES.
&&
.PREV DISCUSSION... /ISSUED 353 PM CDT WED SEP 3 2014/
DISCUSSION...
WARM TEMPERATURES AND BREEZY SOUTHERLY WINDS WERE COMMON ACROSS
EASTERN OKLAHOMA AND NORTHWEST ARKANSAS THIS AFTERNOON AS HIGH
PRESSURE CONTINUED TO HOLD OVER THE SOUTHERN PLAINS. SOME
SCATTERED CONVECTION HAD DEVELOPED OVER FAR SOUTHEAST KANSAS LATE
THIS AFTERNOON...AND THE LATEST HRRR TRIES TO DEVELOP THIS PRECIP
AND PUSH IT SOUTHEAST INTO NORTHWEST/NORTH CENTRAL OKLAHOMA THIS
EVENING AND OVERNIGHT. WILL KEEP POPS BELOW MENTIONABLE CRITERIA
FOR NOW AS MOST OF THIS ACTIVITY SHOULD REMAIN NORTHWEST OF THE
CWA. EVENING SHIFT WILL NEED TO MONITOR FOR ANY CHANGING
CONDITIONS.
HOT TEMPERATURES AND BREEZY SOUTH SOUTHWESTERLY WINDS WILL
CONTINUE ACROSS THE CWA THURSDAY BEFORE A COLD FRONT IS EXPECTED
TO MOVE INTO THE REGION FRIDAY. A WAVE MOVING EASTWARD ALONG THE
U.S./CANADA BORDER WILL PUSH A TRAILING COLD FRONT SOUTHEASTWARD
THROUGH THE PLAINS AND INTO THE CWA DURING THE DAY FRIDAY. CHANCES
FOR SHOWERS AND THUNDERSTORMS BECOME POSSIBLE FRIDAY MORNING AS
THE FRONT NEARS THE REGION AND SHOULD INCREASE IN COVERAGE FRIDAY
AFTERNOON/EVENING WHILE THE FRONT PUSHES INTO THE CWA. CONDITIONS
AHEAD OF THE FRONT AND PRECIP SHOULD CONTINUE TO BE WARM WITH
SOUTHWESTERLY WINDS.
THE FRONTAL BOUNDARY IS FORECAST TO MOVE THROUGH THE REGION FRIDAY
NIGHT AND SATURDAY WITH CONTINUED CHANCES FOR SHOWERS AND
THUNDERSTORMS. POST FRONTAL PRECIP WILL BE POSSIBLE SATURDAY
NIGHT INTO SUNDAY BEFORE THE UPPER LEVEL TROF AXIS ASSOCIATED WITH
THE WAVE OVER SOUTHERN CANADA MOVES OUT OF THE PLAINS. IN THE WAKE
OF THE EXITING TROF...COOLER TEMPS AND NORTHERLY WINDS ARE
EXPECTED ACROSS THE REGION INTO THE START OF THE NEXT WORK WEEK.
SOUTHERLY WINDS QUICKLY RETURN WITH WARMER TEMPERATURES AGAIN FOR
THE MIDDLE PART OF NEXT WEEK AHEAD OF A LONGWAVE TROF FORECAST
TO MOVE OUT OF SOUTHERN CANADA INTO THE PLAINS. LATEST GFS AND
ECMWF DISAGREE ON TIMING OF THIS NEXT WAVE AND ASSOCIATED COLD
FRONT INTO THE CWA. THE ECMWF IS ABOUT 12-24 HRS FASTER COMPARED
TO THE GFS. WILL USE A BLENDED MODEL SOLUTION ALONG WITH PREVIOUS
FORECAST...PUSHING THE FRONT THROUGH WEDNESDAY NIGHT AND THURSDAY.
CHANCES FOR SHOWERS AND THUNDERSTORMS WILL AGAIN BECOME POSSIBLE
MID WEEK AND CONTINUE INTO THE SECOND HALF OF NEXT WEEK AS THE
FRONT MOVES THROUGH. COOLER TEMPS WILL AGAIN BE POSSIBLE LATE NEXT
WEEK.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...23
AREA FORECAST DISCUSSION
NWS TULSA OK
353 PM CDT WED SEP 3 2014
.DISCUSSION...
WARM TEMPERATURES AND BREEZY SOUTHERLY WINDS WERE COMMON ACROSS
EASTERN OKLAHOMA AND NORTHWEST ARKANSAS THIS AFTERNOON AS HIGH
PRESSURE CONTINUED TO HOLD OVER THE SOUTHERN PLAINS. SOME
SCATTERED CONVECTION HAD DEVELOPED OVER FAR SOUTHEAST KANSAS LATE
THIS AFTERNOON...AND THE LATEST HRRR TRIES TO DEVELOP THIS PRECIP
AND PUSH IT SOUTHEAST INTO NORTHWEST/NORTH CENTRAL OKLAHOMA THIS
EVENING AND OVERNIGHT. WILL KEEP POPS BELOW MENTIONABLE CRITERIA
FOR NOW AS MOST OF THIS ACTIVITY SHOULD REMAIN NORTHWEST OF THE
CWA. EVENING SHIFT WILL NEED TO MONITOR FOR ANY CHANGING
CONDITIONS.
HOT TEMPERATURES AND BREEZY SOUTH SOUTHWESTERLY WINDS WILL
CONTINUE ACROSS THE CWA THURSDAY BEFORE A COLD FRONT IS EXPECTED
TO MOVE INTO THE REGION FRIDAY. A WAVE MOVING EASTWARD ALONG THE
U.S./CANADA BORDER WILL PUSH A TRAILING COLD FRONT SOUTHEASTWARD
THROUGH THE PLAINS AND INTO THE CWA DURING THE DAY FRIDAY. CHANCES
FOR SHOWERS AND THUNDERSTORMS BECOME POSSIBLE FRIDAY MORNING AS
THE FRONT NEARS THE REGION AND SHOULD INCREASE IN COVERAGE FRIDAY
AFTERNOON/EVENING WHILE THE FRONT PUSHES INTO THE CWA. CONDITIONS
AHEAD OF THE FRONT AND PRECIP SHOULD CONTINUE TO BE WARM WITH
SOUTHWESTERLY WINDS.
THE FRONTAL BOUNDARY IS FORECAST TO MOVE THROUGH THE REGION FRIDAY
NIGHT AND SATURDAY WITH CONTINUED CHANCES FOR SHOWERS AND
THUNDERSTORMS. POST FRONTAL PRECIP WILL BE POSSIBLE SATURDAY
NIGHT INTO SUNDAY BEFORE THE UPPER LEVEL TROF AXIS ASSOCIATED WITH
THE WAVE OVER SOUTHERN CANADA MOVES OUT OF THE PLAINS. IN THE WAKE
OF THE EXITING TROF...COOLER TEMPS AND NORTHERLY WINDS ARE
EXPECTED ACROSS THE REGION INTO THE START OF THE NEXT WORK WEEK.
SOUTHERLY WINDS QUICKLY RETURN WITH WARMER TEMPERATURES AGAIN FOR
THE MIDDLE PART OF NEXT WEEK AHEAD OF A LONGWAVE TROF FORECAST
TO MOVE OUT OF SOUTHERN CANADA INTO THE PLAINS. LATEST GFS AND
ECMWF DISAGREE ON TIMING OF THIS NEXT WAVE AND ASSOCIATED COLD
FRONT INTO THE CWA. THE ECMWF IS ABOUT 12-24 HRS FASTER COMPARED
TO THE GFS. WILL USE A BLENDED MODEL SOLUTION ALONG WITH PREVIOUS
FORECAST...PUSHING THE FRONT THROUGH WEDNESDAY NIGHT AND THURSDAY.
CHANCES FOR SHOWERS AND THUNDERSTORMS WILL AGAIN BECOME POSSIBLE
MID WEEK AND CONTINUE INTO THE SECOND HALF OF NEXT WEEK AS THE
FRONT MOVES THROUGH. COOLER TEMPS WILL AGAIN BE POSSIBLE LATE NEXT
WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 77 97 75 94 / 0 0 10 30
FSM 74 95 73 95 / 0 10 10 10
MLC 75 95 74 94 / 0 0 0 10
BVO 73 96 69 92 / 0 10 10 40
FYV 69 91 67 92 / 10 10 10 30
BYV 70 93 69 92 / 10 10 10 30
MKO 74 95 73 94 / 0 10 10 30
MIO 73 95 71 91 / 0 10 10 40
F10 75 95 74 94 / 0 0 10 30
HHW 74 95 73 95 / 0 0 0 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...30
LONG TERM....20
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1105 PM EDT THU SEP 4 2014
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO DRIFT EAST OF THE MID ATLANTIC
SEABOARD TONIGHT BRINGING VERY WARM AND HUMID CONDITIONS FOR
FRIDAY. A COLD FRONT WILL MOVE EAST FROM THE OHIO VALLEY AND
CROSS THE STATE SATURDAY AFTERNOON AND EVENING. A REFRESHINGLY
COOLER AND MUCH DRIER AIRMASS WILL OVERSPREAD THE REGION FOR
SUNDAY AND MONDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
EVENING CONVECTION THAT FIRED ON THE RIDGES OF SOMERSET AND
CAMBRIA COUNTIES IS DRIFTING EAST AND SHOWING THE SIGNS OF
WEAKENING THAT THE HRRR HAS BEEN ADVERTISING. PREDICTING.
MAINLY CLEAR SKIES AND LIGHT WIND FOR MUCH OF THE OVERNIGHT WILL
COMBINE WITH THE HIGH DEWPOINTS TO ONCE AGAIN PRODUCE PATCHY DENSE
FOG THROUGHOUT THE DEEPER VALLEYS. MINS TEMPS WILL BE VERY MILD
FOR EARLY SEP - GENERALLY IN THE MID 60S /EXCEPT U50S TO LOWER 60S
ACROSS THE NRN AND WRN MTNS.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
WEAK DEEP-LAYER CONVERGENCE IS EXPECTED FRIDAY ACROSS THE REGION
INVOF A PROJECTED NORTH-SOUTH LEE TROUGH. WARMEST SFC TEMPS AND
HIGHEST SFC DEWPOINTS /WITH NEARLY 2 INCH PWAT AIR/ WILL OCCUR
ACROSS THE LOWER AND MID SUSQ VALLEY WITH THE 15Z SREF`S PROB OF
CAPE EXCEEDING 2000 J/KG INCREASING TO AROUND 50 PERCENT DURING
THE MID TO LATE AFTERNOON HOURS. WILL MAINTAIN 20-30 POPS IN THE
18 FRI- 00Z SAT WINDOW ACROSS ALL OF THE CWA SINCE THE EXACT
LOCATIONS OF THE BEST LLVL FORCING AND WEAKNESSES IN THE MID LEVEL
CAP WILL BE DIFFICULT TO PINPOINT.
TEMPS WILL ONCE AGAIN BE 7 OR 8 DEG F ABOVE NORMAL HIGHS...AND
APPARENT TEMPS BETWEEN 85 AND 90F THROUGHOUT THE CENTRAL VALLEY
AND SUSQ REGION SHOULD BE THE WARMEST WE/LL SEE UNTIL LATER NEXT
SPRING.
A COLD FRONT WILL BE APPROACHING FROM THE GREAT LAKES ON FRIDAY
NIGHT AND PUSH THRU DURING THE DAY SAT. THE POPS WILL STAY RATHER
LOW OVER MOST OF THE AREA WITH ONLY SCT SHRA/TSRA OVERNIGHT...AND
MAINLY LIMITED TO THE NW ZONES. THE NWRN COUNTIES WILL LIKELY SEE
STORMS MOVE DOWN FROM THE NW AFTER MIDNIGHT...BEFORE GRADUALLY
WEAKENING AS THEY APPROACH THE RIDGE AND VALLEY REGION OF CENTRAL
PENN.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
*SHOWERS/TSTMS ON SATURDAY FOLLOWED BY COOLER/DRY WEATHER SUNDAY
INTO MONDAY
*NEAR AVERAGE TEMPERATURES AND MORE UNSETTLED CONDITIONS TUE-THU
THE REGIONAL PATTERN ALOFT WILL FEATURE INCREASING TROUGHINESS
THROUGH THE MEDIUM RANGE PERIOD...WITH THE GLOBAL ENSEMBLE MEANS
SHOWING A CORE OF NEGATIVE HEIGHT ANOMALIES OVER THE UPPER MIDWEST
AND GREAT LAKES REGIONS BY THE MIDDLE TO LATER PART OF NEXT WEEK
/SEPT 11-12TH/. OVERALL...THE NAEFS/GEFS AND ECENS ALL SIGNAL A
TRANSITION TOWARD A HIGHER AMPLITUDE PATTERN PARTICULARLY ACROSS
SOUTH CENTRAL CANADA.
AN ELONGATED COLD FRONT TRAILING A RELATIVELY STRONG SFC LOW OVER
NEWFOUNDLAND/LABRADOR WILL BE THE FOCUS FOR SHOWERS/TSTMS AS IT
CROSSES THE APPALACHIANS ON SAT. A MODIFIED CANADIAN HIGH BUILDING
SWD INTO THE CENTRAL PLAINS WILL EVENTUALLY SHIFT EWD THROUGH THE
NORTHEAST STATES AND MOVE INTO THE MARITIMES BY NEXT WED.
WEAK HEIGHT FALLS WILL OVERSPREAD THE REGION ON SAT...AS A POSITIVE
TILT S/WV TROUGH MOVES EWD FROM THE NRN PLAINS ACROSS THE GREAT
LAKES REGION. ABOVE NORMAL PWS ALONG/AHEAD OF THE LOW LEVEL BOUNDARY
AND SUFFICIENT HEATING/INSTABILITY SHOULD FOSTER NRMS SHOWERS AND
SCT TSTMS WITH SOME LOCALLY HEAVY DOWNPOURS. WITH THE STRONGEST BELT
OF MID-LEVEL FLOW AND DEEP-LAYER SHEAR EXPECTED TO REMAIN NORTH OF
THE AREA ACROSS ONT/QUE AND NRN NEW ENGLAND...THE RISK FOR SVR
STORMS IS LOW. THE PCPN WILL END FROM NW-SE SAT NGT WITH MUCH
DRIER AIR FILTERING IN FOR SUNDAY. DRY WX SHOULD CONTINUE INTO
EARLY NEXT WEEK BEFORE CONDS TURN MORE UNSETTLED. EASTERLY WINDS
TO THE SOUTH OF HP CELL MOVG INTO THE MARITIMES ARE SUGGESTIVE OF
A COOL-AIR WEDGE OVER THE MID-ATLC WHICH SHOULD DAYTIME HIGHS NEAR
AVG.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
AS SKIES CLEAR TONIGHT...AND AS WINDS LIGHTEN...LOCALLY DENSE AND
MAINLY DEEPER VALLEY FOG IS POSSIBLE LATE TONIGHT THROUGH MID
FRIDAY MORNING. MANY LOCATIONS LIKELY TO EXPERIENCE A PERIOD OF
IFR-LIFR CONDS NEAR DAWN FRIDAY.
CONDITIONS WILL GRADUALLY IMPROVE LATE FRI MORNING AND AFTERNOON
WITH A FEW AREAS OF MVFR HAZE LINGERING /ESPECIALLY INVOF KMDT AND
KLNS/. ISOLATED SHRA/TSRA FRIDAY AFTERNOON WILL BRING THE
POTENTIAL FOR BRIEF MVFR CONDITIONS.
OUTLOOK...
FRI...PATCHY AM FOG. ISOLD PM TSRA IMPACTS POSS SOUTHERN PA.
SAT...AM SHRA/LOW CIGS POSS NW MTNS. PM TSRA IMPACTS POSS ELSEWHERE.
SUN...AM FOG POSS NW MTNS.
MON...PATCHY AM VALLEY FOG POSS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LAMBERT
LONG TERM...STEINBUGL
AVIATION...LAMBERT/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1005 PM EDT THU SEP 4 2014
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO DRIFT EAST OF THE MID ATLANTIC
SEABOARD TONIGHT BRINGING VERY WARM AND HUMID CONDITIONS FOR
FRIDAY. A COLD FRONT WILL MOVE EAST FROM THE OHIO VALLEY AND
CROSS THE STATE SATURDAY AFTERNOON AND EVENING. A REFRESHINGLY
COOLER AND MUCH DRIER AIRMASS WILL OVERSPREAD THE REGION FOR
SUNDAY AND MONDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
EVENING CONVECTION THAT FIRED ON THE RIDGES OF SOMERSET AND
CAMBRIA COUNTIES IS DRIFTING EAST AND SHOWING THE SIGNS OF
WEAKENING THAT THE HRRR HAS BEEN ADVERTISING. PREDICTING.
MAINLY CLEAR SKIES AND LIGHT WIND FOR MUCH OF THE OVERNIGHT WILL
COMBINE WITH THE HIGH DEWPOINTS TO ONCE AGAIN PRODUCE PATCHY DENSE
FOG THROUGHOUT THE DEEPER VALLEYS. MINS TEMPS WILL BE VERY MILD
FOR EARLY SEP - GENERALLY IN THE MID 60S /EXCEPT U50S TO LOWER 60S
ACROSS THE NRN AND WRN MTNS.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
WEAK DEEP-LAYER CONVERGENCE IS EXPECTED FRIDAY ACROSS THE REGION
INVOF A PROJECTED NORTH-SOUTH LEE TROUGH. WARMEST SFC TEMPS AND
HIGHEST SFC DEWPOINTS /WITH NEARLY 2 INCH PWAT AIR/ WILL OCCUR
ACROSS THE LOWER AND MID SUSQ VALLEY WITH THE 15Z SREF`S PROB OF
CAPE EXCEEDING 2000 J/KG INCREASING TO AROUND 50 PERCENT DURING
THE MID TO LATE AFTERNOON HOURS. WILL MAINTAIN 20-30 POPS IN THE
18 FRI- 00Z SAT WINDOW ACROSS ALL OF THE CWA SINCE THE EXACT
LOCATIONS OF THE BEST LLVL FORCING AND WEAKNESSES IN THE MID LEVEL
CAP WILL BE DIFFICULT TO PINPOINT.
TEMPS WILL ONCE AGAIN BE 7 OR 8 DEG F ABOVE NORMAL HIGHS...AND
APPARENT TEMPS BETWEEN 85 AND 90F THROUGHOUT THE CENTRAL VALLEY
AND SUSQ REGION SHOULD BE THE WARMEST WE/LL SEE UNTIL LATER NEXT
SPRING.
A COLD FRONT WILL BE APPROACHING FROM THE GREAT LAKES ON FRIDAY
NIGHT AND PUSH THRU DURING THE DAY SAT. THE POPS WILL STAY RATHER
LOW OVER MOST OF THE AREA WITH ONLY SCT SHRA/TSRA OVERNIGHT...AND
MAINLY LIMITED TO THE NW ZONES. THE NWRN COUNTIES WILL LIKELY SEE
STORMS MOVE DOWN FROM THE NW AFTER MIDNIGHT...BEFORE GRADUALLY
WEAKENING AS THEY APPROACH THE RIDGE AND VALLEY REGION OF CENTRAL
PENN.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
*SHOWERS/TSTMS ON SATURDAY FOLLOWED BY COOLER/DRY WEATHER SUNDAY
INTO MONDAY
*NEAR AVERAGE TEMPERATURES AND MORE UNSETTLED CONDITIONS TUE-THU
THE REGIONAL PATTERN ALOFT WILL FEATURE INCREASING TROUGHINESS
THROUGH THE MEDIUM RANGE PERIOD...WITH THE GLOBAL ENSEMBLE MEANS
SHOWING A CORE OF NEGATIVE HEIGHT ANOMALIES OVER THE UPPER MIDWEST
AND GREAT LAKES REGIONS BY THE MIDDLE TO LATER PART OF NEXT WEEK
/SEPT 11-12TH/. OVERALL...THE NAEFS/GEFS AND ECENS ALL SIGNAL A
TRANSITION TOWARD A HIGHER AMPLITUDE PATTERN PARTICULARLY ACROSS
SOUTH CENTRAL CANADA.
AN ELONGATED COLD FRONT TRAILING A RELATIVELY STRONG SFC LOW OVER
NEWFOUNDLAND/LABRADOR WILL BE THE FOCUS FOR SHOWERS/TSTMS AS IT
CROSSES THE APPALACHIANS ON SAT. A MODIFIED CANADIAN HIGH BUILDING
SWD INTO THE CENTRAL PLAINS WILL EVENTUALLY SHIFT EWD THROUGH THE
NORTHEAST STATES AND MOVE INTO THE MARITIMES BY NEXT WED.
WEAK HEIGHT FALLS WILL OVERSPREAD THE REGION ON SAT...AS A POSITIVE
TILT S/WV TROUGH MOVES EWD FROM THE NRN PLAINS ACROSS THE GREAT
LAKES REGION. ABOVE NORMAL PWS ALONG/AHEAD OF THE LOW LEVEL BOUNDARY
AND SUFFICIENT HEATING/INSTABILITY SHOULD FOSTER NRMS SHOWERS AND
SCT TSTMS WITH SOME LOCALLY HEAVY DOWNPOURS. WITH THE STRONGEST BELT
OF MID-LEVEL FLOW AND DEEP-LAYER SHEAR EXPECTED TO REMAIN NORTH OF
THE AREA ACROSS ONT/QUE AND NRN NEW ENGLAND...THE RISK FOR SVR
STORMS IS LOW. THE PCPN WILL END FROM NW-SE SAT NGT WITH MUCH
DRIER AIR FILTERING IN FOR SUNDAY. DRY WX SHOULD CONTINUE INTO
EARLY NEXT WEEK BEFORE CONDS TURN MORE UNSETTLED. EASTERLY WINDS
TO THE SOUTH OF HP CELL MOVG INTO THE MARITIMES ARE SUGGESTIVE OF
A COOL-AIR WEDGE OVER THE MID-ATLC WHICH SHOULD DAYTIME HIGHS NEAR
AVG.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
LOCAL CONVECTION CONTINUES ACROSS THE LAURELS AS SHOWERS AND AN
ISOLATED TSRA WILL MOVE NEAR KAOO AND JUST EAST OF KJST. ANY
LINGERING SHOWERS/STORMS WILL CEASE OVER THE NEXT HOUR.
AS SKIES CLEAR TONIGHT...AND AS WINDS LIGHTEN...LOCALLY
DENSE AND MAINLY DEEPER VALLEY FOG IS POSSIBLE LATE TONIGHT
THROUGH MID FRIDAY MORNING. MANY LOCATIONS LIKELY TO EXPERIENCE A
PERIOD OF IFR-LIFR CONDS NEAR DAWN FRIDAY.
CONDITIONS WILL GRADUALLY IMPROVE LATE FRI MORNING AND AFTERNOON
WITH A FEW AREAS OF MVFR HAZE LINGERING /ESPECIALLY INVOF KMDT AND
KLNS/. ISOLATED SHRA/TSRA FRIDAY AFTERNOON WILL BRING THE
POTENTIAL FOR BRIEF MVFR CONDITIONS.
OUTLOOK...
FRI...PATCHY AM FOG. ISOLD PM TSRA IMPACTS POSS SOUTHERN PA.
SAT...AM SHRA/LOW CIGS POSS NW MTNS. PM TSRA IMPACTS POSS ELSEWHERE.
SUN...AM FOG POSS NW MTNS.
MON...PATCHY AM VALLEY FOG POSS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LAMBERT
LONG TERM...STEINBUGL
AVIATION...LAMBERT/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
911 PM EDT THU SEP 4 2014
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO DRIFT EAST OF THE MID ATLANTIC
SEABOARD TONIGHT BRINGING VERY WARM AND HUMID CONDITIONS FOR
FRIDAY. A COLD FRONT WILL MOVE EAST FROM THE OHIO VALLEY AND
CROSS THE STATE SATURDAY AFTERNOON AND EVENING. A REFRESHINGLY
COOLER AND MUCH DRIER AIRMASS WILL OVERSPREAD THE REGION FOR
SUNDAY AND MONDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
WEAK MOISTURE CONVERGENCE...CAPES BETWEEN 1000-1500J AND MID LEVEL
LAPSE RATES IN EXCESS OF 6C/KM HAVE FINALLY CONSPIRED TO ALLOW
CONVECTION TO FIRE OVER THE RIDGES OF THE LAURELS FROM CENTRAL
SOMERSET UP TO NORTHERN CAMBRIA COUNTY. HRRR SHOWS THE ACTIVITY
SLOWLY DRIFTING EAST OVER THE NEXT COUPLE OF HOURS BEFORE FADING
AFTER DARK. HAVE INCLUDED A SLIGHT CHANCE UP INTO SOUTHERN
CLEARFIELD AND CENTRE COUNTIES TO CATCH THIS SLOWLY MEANDERING
LATE DAY-EARLY EVENING ACTIVITY.
MAINLY CLEAR SKIES AND LIGHT WIND FOR MUCH OF THE OVERNIGHT WILL
COMBINE WITH THE HIGH DEWPOINTS TO ONCE AGAIN PRODUCE PATCHY DENSE
FOG THROUGHOUT THE DEEPER VALLEYS. MINS TEMPS WILL BE VERY MILD
FOR EARLY SEP - GENERALLY IN THE MID 60S /EXCEPT U50S TO LOWER 60S
ACROSS THE NRN AND WRN MTNS.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
WEAK DEEP-LAYER CONVERGENCE IS EXPECTED FRIDAY ACROSS THE REGION
INVOF A PROJECTED NORTH-SOUTH LEE TROUGH. WARMEST SFC TEMPS AND
HIGHEST SFC DEWPOINTS /WITH NEARLY 2 INCH PWAT AIR/ WILL OCCUR
ACROSS THE LOWER AND MID SUSQ VALLEY WITH THE 15Z SREF`S PROB OF
CAPE EXCEEDING 2000 J/KG INCREASING TO AROUND 50 PERCENT DURING
THE MID TO LATE AFTERNOON HOURS. WILL MAINTAIN 20-30 POPS IN THE
18 FRI- 00Z SAT WINDOW ACROSS ALL OF THE CWA SINCE THE EXACT
LOCATIONS OF THE BEST LLVL FORCING AND WEAKNESSES IN THE MID LEVEL
CAP WILL BE DIFFICULT TO PINPOINT.
TEMPS WILL ONCE AGAIN BE 7 OR 8 DEG F ABOVE NORMAL HIGHS...AND
APPARENT TEMPS BETWEEN 85 AND 90F THROUGHOUT THE CENTRAL VALLEY
AND SUSQ REGION SHOULD BE THE WARMEST WE/LL SEE UNTIL LATER NEXT
SPRING.
A COLD FRONT WILL BE APPROACHING FROM THE GREAT LAKES ON FRIDAY
NIGHT AND PUSH THRU DURING THE DAY SAT. THE POPS WILL STAY RATHER
LOW OVER MOST OF THE AREA WITH ONLY SCT SHRA/TSRA OVERNIGHT...AND
MAINLY LIMITED TO THE NW ZONES. THE NWRN COUNTIES WILL LIKELY SEE
STORMS MOVE DOWN FROM THE NW AFTER MIDNIGHT...BEFORE GRADUALLY
WEAKENING AS THEY APPROACH THE RIDGE AND VALLEY REGION OF CENTRAL
PENN.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
*SHOWERS/TSTMS ON SATURDAY FOLLOWED BY COOLER/DRY WEATHER SUNDAY
INTO MONDAY
*NEAR AVERAGE TEMPERATURES AND MORE UNSETTLED CONDITIONS TUE-THU
THE REGIONAL PATTERN ALOFT WILL FEATURE INCREASING TROUGHINESS
THROUGH THE MEDIUM RANGE PERIOD...WITH THE GLOBAL ENSEMBLE MEANS
SHOWING A CORE OF NEGATIVE HEIGHT ANOMALIES OVER THE UPPER MIDWEST
AND GREAT LAKES REGIONS BY THE MIDDLE TO LATER PART OF NEXT WEEK
/SEPT 11-12TH/. OVERALL...THE NAEFS/GEFS AND ECENS ALL SIGNAL A
TRANSITION TOWARD A HIGHER AMPLITUDE PATTERN PARTICULARLY ACROSS
SOUTH CENTRAL CANADA.
AN ELONGATED COLD FRONT TRAILING A RELATIVELY STRONG SFC LOW OVER
NEWFOUNDLAND/LABRADOR WILL BE THE FOCUS FOR SHOWERS/TSTMS AS IT
CROSSES THE APPALACHIANS ON SAT. A MODIFIED CANADIAN HIGH BUILDING
SWD INTO THE CENTRAL PLAINS WILL EVENTUALLY SHIFT EWD THROUGH THE
NORTHEAST STATES AND MOVE INTO THE MARITIMES BY NEXT WED.
WEAK HEIGHT FALLS WILL OVERSPREAD THE REGION ON SAT...AS A POSITIVE
TILT S/WV TROUGH MOVES EWD FROM THE NRN PLAINS ACROSS THE GREAT
LAKES REGION. ABOVE NORMAL PWS ALONG/AHEAD OF THE LOW LEVEL BOUNDARY
AND SUFFICIENT HEATING/INSTABILITY SHOULD FOSTER NRMS SHOWERS AND
SCT TSTMS WITH SOME LOCALLY HEAVY DOWNPOURS. WITH THE STRONGEST BELT
OF MID-LEVEL FLOW AND DEEP-LAYER SHEAR EXPECTED TO REMAIN NORTH OF
THE AREA ACROSS ONT/QUE AND NRN NEW ENGLAND...THE RISK FOR SVR
STORMS IS LOW. THE PCPN WILL END FROM NW-SE SAT NGT WITH MUCH
DRIER AIR FILTERING IN FOR SUNDAY. DRY WX SHOULD CONTINUE INTO
EARLY NEXT WEEK BEFORE CONDS TURN MORE UNSETTLED. EASTERLY WINDS
TO THE SOUTH OF HP CELL MOVG INTO THE MARITIMES ARE SUGGESTIVE OF
A COOL-AIR WEDGE OVER THE MID-ATLC WHICH SHOULD DAYTIME HIGHS NEAR
AVG.
&&
.AVIATION /01Z FRIDAY THROUGH TUESDAY/...
LOCAL CONVECTION CONTINUES ACROSS THE LAURELS AS SHOWERS AND AN
ISOLATED TSRA WILL MOVE NEAR KAOO AND JUST EAST OF KJST. ANY
LINGERING SHOWERS/STORMS WILL CEASE OVER THE NEXT HOUR.
AS SKIES CLEAR TONIGHT...AND AS WINDS LIGHTEN...LOCALLY
DENSE AND MAINLY DEEPER VALLEY FOG IS POSSIBLE LATE TONIGHT
THROUGH MID FRIDAY MORNING. MANY LOCATIONS LIKELY TO EXPERIENCE A
PERIOD OF IFR-LIFR CONDS NEAR DAWN FRIDAY.
CONDITIONS WILL GRADUALLY IMPROVE LATE FRI MORNING AND AFTERNOON
WITH A FEW AREAS OF MVFR HAZE LINGERING /ESPECIALLY INVOF KMDT AND
KLNS/. ISOLATED SHRA/TSRA FRIDAY AFTERNOON WILL BRING THE
POTENTIAL FOR BRIEF MVFR CONDITIONS.
OUTLOOK...
FRI...PATCHY AM FOG. ISOLD PM TSRA IMPACTS POSS SOUTHERN PA.
SAT...AM SHRA/LOW CIGS POSS NW MTNS. PM TSRA IMPACTS POSS ELSEWHERE.
SUN...AM FOG POSS NW MTNS.
MON...PATCHY AM VALLEY FOG POSS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE/LAMBERT
NEAR TERM...LA CORTE/LAMBERT
SHORT TERM...LAMBERT
LONG TERM...STEINBUGL
AVIATION...LAMBERT/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
724 PM EDT THU SEP 4 2014
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO DRIFT EAST OF THE MID ATLANTIC
SEABOARD TONIGHT BRINGING VERY WARM AND HUMID CONDITIONS FOR
FRIDAY. A COLD FRONT WILL MOVE EAST FROM THE OHIO VALLEY AND
CROSS THE STATE SATURDAY AFTERNOON AND EVENING. A REFRESHINGLY
COOLER AND MUCH DRIER AIRMASS WILL OVERSPREAD THE REGION FOR
SUNDAY AND MONDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
WEAK MOISTURE CONVERGENCE...CAPES BETWEEN 1000-1500J AND MID LEVEL
LAPSE RATES IN EXCESS OF 6C/KM HAVE FINALLY CONSPIRED TO ALLOW
CONVECTION TO FIRE OVER THE RIDGES OF THE LAURELS FROM CENTRAL
SOMERSET UP TO NORTHERN CAMBRIA COUNTY. HRRR SHOWS THE ACTIVITY
SLOWLY DRIFTING EAST OVER THE NEXT COUPLE OF HOURS BEFORE FADING
AFTER DARK. HAVE INCLUDED A SLIGHT CHANCE UP INTO SOUTHERN
CLEARFIELD AND CENTRE COUNTIES TO CATCH THIS SLOWLY MEANDERING
LATE DAY-EARLY EVENING ACTIVITY.
MAINLY CLEAR SKIES AND LIGHT WIND FOR MUCH OF THE OVERNIGHT WILL
COMBINE WITH THE HIGH DEWPOINTS TO ONCE AGAIN PRODUCE PATCHY DENSE
FOG THROUGHOUT THE DEEPER VALLEYS. MINS TEMPS WILL BE VERY MILD
FOR EARLY SEP - GENERALLY IN THE MID 60S /EXCEPT U50S TO LOWER 60S
ACROSS THE NRN AND WRN MTNS.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
WEAK DEEP-LAYER CONVERGENCE IS EXPECTED FRIDAY ACROSS THE REGION
INVOF A PROJECTED NORTH-SOUTH LEE TROUGH. WARMEST SFC TEMPS AND
HIGHEST SFC DEWPOINTS /WITH NEARLY 2 INCH PWAT AIR/ WILL OCCUR
ACROSS THE LOWER AND MID SUSQ VALLEY WITH THE 15Z SREF`S PROB OF
CAPE EXCEEDING 2000 J/KG INCREASING TO AROUND 50 PERCENT DURING
THE MID TO LATE AFTERNOON HOURS. WILL MAINTAIN 20-30 POPS IN THE
18 FRI- 00Z SAT WINDOW ACROSS ALL OF THE CWA SINCE THE EXACT
LOCATIONS OF THE BEST LLVL FORCING AND WEAKNESSES IN THE MID LEVEL
CAP WILL BE DIFFICULT TO PINPOINT.
TEMPS WILL ONCE AGAIN BE 7 OR 8 DEG F ABOVE NORMAL HIGHS...AND
APPARENT TEMPS BETWEEN 85 AND 90F THROUGHOUT THE CENTRAL VALLEY
AND SUSQ REGION SHOULD BE THE WARMEST WE/LL SEE UNTIL LATER NEXT
SPRING.
A COLD FRONT WILL BE APPROACHING FROM THE GREAT LAKES ON FRIDAY
NIGHT AND PUSH THRU DURING THE DAY SAT. THE POPS WILL STAY RATHER
LOW OVER MOST OF THE AREA WITH ONLY SCT SHRA/TSRA OVERNIGHT...AND
MAINLY LIMITED TO THE NW ZONES. THE NWRN COUNTIES WILL LIKELY SEE
STORMS MOVE DOWN FROM THE NW AFTER MIDNIGHT...BEFORE GRADUALLY
WEAKENING AS THEY APPROACH THE RIDGE AND VALLEY REGION OF CENTRAL
PENN.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
*SHOWERS/TSTMS ON SATURDAY FOLLOWED BY COOLER/DRY WEATHER SUNDAY
INTO MONDAY
*NEAR AVERAGE TEMPERATURES AND MORE UNSETTLED CONDITIONS TUE-THU
THE REGIONAL PATTERN ALOFT WILL FEATURE INCREASING TROUGHINESS
THROUGH THE MEDIUM RANGE PERIOD...WITH THE GLOBAL ENSEMBLE MEANS
SHOWING A CORE OF NEGATIVE HEIGHT ANOMALIES OVER THE UPPER MIDWEST
AND GREAT LAKES REGIONS BY THE MIDDLE TO LATER PART OF NEXT WEEK
/SEPT 11-12TH/. OVERALL...THE NAEFS/GEFS AND ECENS ALL SIGNAL A
TRANSITION TOWARD A HIGHER AMPLITUDE PATTERN PARTICULARLY ACROSS
SOUTH CENTRAL CANADA.
AN ELONGATED COLD FRONT TRAILING A RELATIVELY STRONG SFC LOW OVER
NEWFOUNDLAND/LABRADOR WILL BE THE FOCUS FOR SHOWERS/TSTMS AS IT
CROSSES THE APPALACHIANS ON SAT. A MODIFIED CANADIAN HIGH BUILDING
SWD INTO THE CENTRAL PLAINS WILL EVENTUALLY SHIFT EWD THROUGH THE
NORTHEAST STATES AND MOVE INTO THE MARITIMES BY NEXT WED.
WEAK HEIGHT FALLS WILL OVERSPREAD THE REGION ON SAT...AS A POSITIVE
TILT S/WV TROUGH MOVES EWD FROM THE NRN PLAINS ACROSS THE GREAT
LAKES REGION. ABOVE NORMAL PWS ALONG/AHEAD OF THE LOW LEVEL BOUNDARY
AND SUFFICIENT HEATING/INSTABILITY SHOULD FOSTER NRMS SHOWERS AND
SCT TSTMS WITH SOME LOCALLY HEAVY DOWNPOURS. WITH THE STRONGEST BELT
OF MID-LEVEL FLOW AND DEEP-LAYER SHEAR EXPECTED TO REMAIN NORTH OF
THE AREA ACROSS ONT/QUE AND NRN NEW ENGLAND...THE RISK FOR SVR
STORMS IS LOW. THE PCPN WILL END FROM NW-SE SAT NGT WITH MUCH
DRIER AIR FILTERING IN FOR SUNDAY. DRY WX SHOULD CONTINUE INTO
EARLY NEXT WEEK BEFORE CONDS TURN MORE UNSETTLED. EASTERLY WINDS
TO THE SOUTH OF HP CELL MOVG INTO THE MARITIMES ARE SUGGESTIVE OF
A COOL-AIR WEDGE OVER THE MID-ATLC WHICH SHOULD DAYTIME HIGHS NEAR
AVG.
&&
.AVIATION /23Z THURSDAY THROUGH TUESDAY/...
WIDESPREAD VFR CONDS WILL OCCUR FOR THE REST OF TODAY...AS HIGH
PRES MOVES OFF THE MID ATLANTIC COAST. AREAS OF BKN STRATO CU
BASED BETWEEN 3.5-4 KFT AGL WILL PREVAIL ACROSS THE SUSQ VALLEY
AND NCENT MTNS IN A N/S CONVERGENCE ZONE BETWEEN A LIGHT SERLY
FLOW OF MOIST AIR OFF THE ATLANTIC...AND SWRLY FLOW ACROSS THE
MTNS OF WESTERN PENN.
CLEAR SKIES AND A LIGHT WIND WILL PROMOTE LOCALLY DENSE...MAINLY
DEEPER VALLEY FOG LATE TONIGHT THROUGH THE MID MORNING FRIDAY WITH
MANY LOCATIONS LIKELY TO EXPERIENCE A PERIOD OF IFR-LIFR CONDS
NEAR DAWN FRIDAY.
CONDITIONS WILL GRADUALLY IMPROVE LATE FRI MORNING AND AFTERNOON
WITH A FEW AREAS OF MVFR HAZE LINGERING /ESPECIALLY INVOF KMDT AND
KLNS/. ISOLATED SHRA/TSRA FRIDAY AFTERNOON WILL BRING THE
POTENTIAL FOR BRIEF MVFR CONDITIONS.
OUTLOOK...
FRI...PATCHY AM FOG. ISOLD PM TSRA IMPACTS POSS SOUTHERN PA.
SAT...AM SHRA/LOW CIGS POSS NW MTNS. PM TSRA IMPACTS POSS ELSEWHERE.
SUN...AM FOG POSS NW MTNS.
MON...PATCHY AM VALLEY FOG POSS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE/LAMBERT
NEAR TERM...LA CORTE/LAMBERT
SHORT TERM...LAMBERT
LONG TERM...STEINBUGL
AVIATION...LAMBERT
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1132 PM CDT TUE SEP 2 2014
.AVIATION...
CONFIDENCE IS A BIT LOWER THAT AN IFR OR MVFR CLOUD DECK WILL
DEVELOP NEAR OR SOUTHWEST OF KLBB EARLY WEDNESDAY...AND ADVECT
OVER THE AIRPORT. LATEST WRF/NAM HAS DRIED THE H850 MB A BIT WHILE
THE RAP H850 MB LAYER IS SLIGHTLY MORE MOIST THAN PREVIOUS RUNS.
ALTHOUGH WE WILL BACK OFF SLIGHTLY ON THE CLOUD LAYER POTENTIAL...
WE WILL RETAIN SOME CHANCE OF A DECK IMPACTING KLBB JUST AFTER
DAYBREAK WEDNESDAY. OTHERWISE...UPPER LEVEL HIGH PRESSURE WILL
DOMINATE THROUGH WEDNESDAY WITH WEAKER FLOW THAN TUESDAY AND
LESSER THUNDER CHANCES. A LOW LEVEL JET TONIGHT SHOULD REMAIN JUST
TO THE NORTH OF THE AREA. RMCQUEEN
&&
.PREV DISCUSSION... /ISSUED 706 PM CDT TUE SEP 2 2014/
AVIATION...
ISOLATED THUNDERSTORMS APPEAR TO HAVE BY-PASSED KLBB WHILE
REMAINING FAR WEST OF KCDS THIS EVENING. VFR EXPECTED TO DOMINATE
OTHER THAN A RISK FOR AN IFR/MVFR CLOUD LAYER TO DEVELOP JUST
AFTER DAYBREAK WEDNESDAY AT KLBB. RMCQUEEN
PREV DISCUSSION... /ISSUED 531 PM CDT TUE SEP 2 2014/
UPDATE...
THUNDERSTORMS HAVE DEVELOPED OVER THE WESTERN AND CENTRAL SOUTH
PLAINS...A BIT SOUTH OF PREVIOUS BEST-GUESS...BUT GIVE SHORT TERM
SOLUTIONS SOME CREDIT. WE HAVE UPDATED FOR LOW COVERAGE THUNDER
THROUGH EARLY THIS EVENING. 1500-2000 JOULES PER KILOGRAM OF
CONVECTIVE ENERGY BUT VERY LITTLE SHEAR CONTRIBUTING TO BRIEF
HEAVY SHOWERS AND BRIEF MOSTLY WEAK HAIL INDICATIONS AT THIS TIME.
ACTIVITY SHOULD TAKE ON BETTER NORTHERLY DRIFT...THOUGH BELIEVE
MOST ACTIVITY WILL RELENT BY DARK. RMCQUEEN
PREV DISCUSSION... /ISSUED 306 PM CDT TUE SEP 2 2014/
SHORT TERM...
FOCUS IN THE SHORT TERM IS ON SMALL CHANCE FOR ISOLATED SHOWERS
AND/OR THUNDERSTORMS LATE THIS AFTN AND THIS EVENING. RADAR IS QUIET
ATTM BUT SATELLITE SHOWING AN AREA OF CUMULUS DEVELOPMENT TO THE
EAST AND SOUTHEAST OF LUBBOCK IN AN AREA WHERE OBJECTIVE ANALYSIS
SHOWS ENHANCED INSTABILITY AND WEAKENING INHIBITION. SOME VERY
MODEST LOW LEVEL SPEED CONVERGENCE AND MOISTURE ADVECTION IN THIS
AREA MAY NOT HELP TOO MUCH BUT CERTAINLY WILL NOT HURT. A WEAK
FRONTAL BOUNDARY PULLED UP STATIONARY NEAR A MORTON TO TULIA LINE
WITH WEAK CONFLUENCE IN ITS VICINITY BUT WITH SFC DEW POINTS ABOUT 5
DEGREES LOWER THAN IN THE FORMER AREA. WOULD EXPECT THESE TWO AREAS
HAVE THE BEST CHANCE OF SEEING CONVECTIVE DEVELOPMENT. 12Z WRF-NAM
HIGHLIGHTS THE LATTER WHILE RECENT RUNS OF THE HRRR FEATURES THE
FORMER. EITHER WAY WILL LIKELY BE DIFFICULT TO GENERATE ANYTHING
OTHER THAN SMALL-SCALE AND ISOLATED SHOWERS WITH AREAL COVERAGE NOT
WARRANTING MENTION IN THE ZONE FCST ATTM.
WEDNESDAY SHOULD BE EVEN MORE DIFFICULT TO PRODUCE PRECIP WITH
STRENGTHENING HIGH PRESSURE OVERHEAD AND LOW LEVEL FLOW BECOMING
MORE UNIFORM FROM THE SOUTH. TEMPS TO REMAIN WARMER THAN NORMAL WITH
BOTH LOWS AND HIGHS NEAR WARMER MAV GUIDANCE LOOKING MORE LIKELY
ATTM.
LONG TERM...
ONLY MINOR CHANGES TO THE LONG TERM FORECAST FOR THIS ITERATION...AS
A MUTED COOLING TREND WILL BE FOLLOWED BY A POTENTIALLY WET WEEKEND
FOR PARTS OF THE REGION.
BY WEDNESDAY EVENING...A MOSTLY ZONAL UPPER FLOW REGIME WILL BE IN
PLACE ACROSS THE CONUS...WITH AN ELONGATED UPPER RIDGE IN PLACE
ACROSS MOST OF THE SOUTH...INCLUDING WEST TEXAS. WHILE THIS WILL
CONTINUE TO ENSURE MOSTLY DRY CONDITIONS THROUGH THE END OF THE WORK
WEEK...GRADUALLY DROPPING 1000-500 MB THICKNESSES WILL ALLOW
TEMPERATURES TO INCREMENTALLY FALL BACK TO A MORE REASONABLE UPPER
80S ON THE SOUTH PLAINS TO MID 90S ON THE ROLLING PLAINS.
BY LATE IN THE WEEK AND THROUGH THE WEEKEND...A BROAD UPPER TROUGH
WILL PUSH EASTWARD ACROSS THE NORTHERN CONUS...SENDING A
MODEST COLD FRONT SOUTHWARD THROUGH THE CENTRAL PLAINS AND AT LEAST
THE TEXAS PANHANDLE. MEANWHILE DEEPER MONSOONAL MOISTURE...POSSIBLY
WITH A CONNECTION TO REMNANTS OF TROPICAL STORM DOLLY...WILL BE
DRAWN NORTHWARD INTO THE SOUTHWEST AND EVENTUALLY EASTWARD AS IT
GETS CAUGHT IN THE WESTERLY UPPER FLOW ASSOCIATED WITH THE
PREVIOUSLY MENTIONED TROUGH. ALL OF THIS IS EXPECTED TO RESULT IN
INCREASING RAIN CHANCES BEGINNING AS EARLY AS LATE FRIDAY...AND
POSSIBLY LASTING THROUGH LATE SUNDAY DEPENDING ON A FEW FACTORS.
THE MOST PROMINENT OF THESE FACTORS SEEMS TO BE THE TIMING AND
STRENGTH OF THE APPROACHING COLD FRONT...AS THE GFS AND ECMWF REMAIN
ABOUT 24 HOURS APART IN THIS REGARD. THE GFS INDICATES A
SLOWER...WEAKER FRONT REACHING THE NORTHERN BORDER OF THE CWA LATE
SATURDAY AFTERNOON AND WASHING OUT ACROSS THE CWA SUNDAY.
MEANWHILE...THE ECMWF SOLUTION BRINGS THIS FRONT INTO THE AREA AS
EARLY AS LATE FRIDAY...AND PUSHES THE BOUNDARY WELL THROUGH THE CWA
BY LATE SATURDAY. THE LATTER SOLUTION NOT SURPRISINGLY DEVELOPS THE
HEAVIEST PRECIPITATION DURING THE LATE FRIDAY THROUGH SATURDAY
TIME FRAME...WHILE THE GFS SEEMS TO BE FOCUSING ON THE LATE SATURDAY
THROUGH LATE SUNDAY TIME FRAME. GIVEN THAT THE BOUNDARY WILL BE WELL
REMOVED FROM ITS PARENT TROUGH BY THE TIME IT REACHES THIS
LATITUDE...WE WILL CONTINUE TO SIDE WITH THE SLOWER GFS SOLUTION AND
HIGHLIGHT LATE SATURDAY WITH THE HIGHEST POPS. LIKEWISE...LOW END POPS
WERE ALSO EXTENDED THROUGH SUNDAY EVENING GIVEN THAT IN THIS SLOWER
SCENARIO REMNANTS OF THIS BOUNDARY AND AMPLE MOISTURE WOULD LIKELY
LINGER THROUGH THIS PERIOD. HOWEVER...UNCERTAINTIES REGARDING
FRONTAL TIMING AND STRENGTH ARE COMPOUNDED FURTHER ON SUNDAY WITH
THE POSSIBILITY OF LINGERING NOCTURNAL CONVECTION AND STABILIZING
OUTFLOWS.
BY MONDAY...THE UPPER RIDGE IS EXPECTED TO SLIGHTLY AMPLIFY ACROSS
THE SOUTHERN PLAINS WHILE THE COLUMN DRIES CONSIDERABLY. THIS
SHOULD TAPER OFF PRECIPITATION CHANCES UNTIL LATER IN THE WEEK WHEN
ANOTHER POSSIBLY STRONGER COLD FRONT MOVES THROUGH THE REGION.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 61 92 62 90 62 / 10 0 10 10 10
TULIA 68 93 66 91 66 / 20 0 10 0 10
PLAINVIEW 68 93 66 90 66 / 20 0 0 0 10
LEVELLAND 66 92 66 90 67 / 20 0 10 10 0
LUBBOCK 72 93 68 92 67 / 20 0 0 10 0
DENVER CITY 66 91 66 89 66 / 20 0 10 10 10
BROWNFIELD 68 93 67 90 67 / 20 0 0 10 0
CHILDRESS 75 97 75 96 72 / 10 0 0 0 0
SPUR 73 97 72 94 71 / 10 0 0 10 10
ASPERMONT 76 99 74 96 73 / 0 0 0 10 10
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
99/99/05
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
855 PM CDT THU SEP 4 2014
.UPDATE...
ISSUED AT 855 PM CDT THU SEP 4 2014
CONFIDENCE IS LOWERING ON POTENTIAL FOR SHOWERS AND THUNDERSTORMS
TONIGHT. LATEST SURFACE ANALYSIS SHOWS A COLD FRONT FROM NEAR
MENOMONIE WI TO WABASHA MN AND CHARLES CITY IA. RAP SHOWS LESS
THAN 25 J/KG CIN ACROSS MUCH OF THE FORECAST
AREA...HOWEVER...SURFACE BASED CIN IS MORE ON THE ORDER OF 50-75
J/KG. THIS CIN REFLECTS CAPPING IN PLACE SEEN ON THE 00Z MPX
SOUNDING. STILL WAITING TO SEE IF FRONTOGENESIS ON AND BEHIND THE
COLD FRONT CAN INITIATE CONVECTION. CERTAINLY PLENTY OF
INSTABILITY SHOULD THE CAP WEAKEN AS ALSO SEEN ON THE 00Z MPX
SOUNDING...THUS CANNOT REMOVE CHANCES COMPLETELY FOR THE REST OF
TONIGHT. SHOULD CONVECTION DEVELOP...AN ISOLATED SEVERE STORM IS
POSSIBLE...PARTICULARLY HERE DURING THE EVENING HOURS. AFTER
MIDNIGHT...CAPE DIMINISHES WHICH WILL LIMIT SEVERE POTENTIAL.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 327 PM CDT THU SEP 4 2014
MAIN FORECAST CONCERNS ARE ON THE POTENTIAL FOR SEVERE THUNDERSTORMS.
LATEST SURFACE ANALYSIS PLACED LOW PRESSURE OVER CENTRAL
MINNESOTA...EDGING EAST. A COLD FRONT EXTENDED SOUTHWARD INTO WESTERN
IOWA WHILE A WARM FRONT WAS POSITIONED NEAR THE INTERSTATE 94
CORRIDOR IN EAST CENTRAL MINNESOTA THROUGH WESTERN WISCONSIN.
EXTENSIVE CLOUD COVER OVER MUCH OF THE FORECAST AREA WAS HELPING TO
HOLD TEMPERATURES DOWN A BIT. SHOWERS AND STORMS ARE DEVELOPING
ACROSS AREAS NORTH OF INTERSTATE 90 DESPITE A FAIRLY STOUT CAP IN
PLACE. FORECAST SOUNDINGS ARE INDICATING 750 MB TEMPERATURES
HOVERING RIGHT AROUND 15 C. SOUNDINGS SUGGEST THIS CAP WILL WEAKEN
AS A SHORTWAVE APPROACHES FROM NEBRASKA/SOUTH DAKOTA THIS AFTERNOON
INTO THIS EVENING JUST AS THE COLD FRONT IS MAKING ITS WAY INTO
NORTHWESTERN SECTIONS OF THE FORECAST AREA. MESOSCALE MODELS ARE
FIRING SHOWERS AND STORMS ALONG AND BEHIND THE FRONT THIS EVENING.
IF THIS SCENARIO PLAYS OUT...THE MAIN THREATS FROM THE STORMS WOULD
BE LARGE HAIL AND HEAVY RAINFALL. WE SHOULD SEE A BAND OF SHOWERS
AND STORMS DEVELOP RIGHT OVER THE FORECAST AREA THIS EVENING THEN
THIS BAND WILL GRADUALLY PUSH SOUTHEAST DURING THE OVERNIGHT HOURS
AS THE FRONT SAGS SOUTHWARD. MUCH COOLER AIR PUSHES INTO THE
FORECAST AREA IN THE WAKE OF THE FRONT TONIGHT INTO FRIDAY WITH 850
MB TEMPS GOING FROM 25 C THIS AFTERNOON TO AROUND 10 C BY FRIDAY
AFTERNOON. A VERY COMFORTABLE DAY IS IN STORE FOR THE REGION ON
FRIDAY AS HIGH PRESSURE BUILDS IN FROM THE WEST. PLAN PARTLY SUNNY
SKIES ACROSS THE REGION WITH HIGHS RANGING FROM THE MID 60 TO LOWER
70S.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 327 PM CDT THU SEP 4 2014
HIGH PRESSURE REMAINS IN CONTROL FRIDAY NIGHT INTO SUNDAY AS THE
REGION REMAINS IN A COOL NORTHWEST FLOW REGIME. WITH THE RIDGE AXIS
NEARBY PROVIDING LIGHT AND VARIABLE WINDS FROM THE SURFACE THROUGH 2
KFT MAY SET THE STAGE FOR AREAS OF FOG LATE SATURDAY NIGHT INTO
SUNDAY MORNING. HAVE INCLUDED PATCHY FOG ALONG RIVER VALLEY
LOCATIONS AND OVER CENTRAL WISCONSIN DURING THIS TIMEFRAME. THE NEXT
CHANCE FOR SHOWERS AND STORMS ACROSS THE REGION ARRIVES ON MONDAY AS
FLOW ALOFT TURNS MORE ZONAL AND A SHORTWAVE TROUGH MOVES IN FROM THE
PLAINS. TEMPERATURES WILL REMAIN SEASONABLY COOL THROUGH THE PERIOD
WITH HIGHS MAINLY IN THE 70S. A MORE UNSETTLED PATTERN IS EXPECTED
TO DEVELOP NEXT WEEK AND WILL REMAIN OVER THE REGION THROUGH
THURSDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 855 PM CDT THU SEP 4 2014
CONFIDENCE HAS LOWERED ON THE POTENTIAL FOR SHOWERS AND
THUNDERSTORMS TO IMPACT LSE. THEREFORE...HAVE REMOVED THE TEMPO
GROUP. STILL CANNOT RULE OUT SOME SHOWERS AND STORMS DEVELOPING
AND POSSIBLY IMPACTING THE TAF SITES OVER THE NEXT FEW
HOURS...THUS HAVE MAINTAINED THE VCTS.
PREVIOUS AVIATION DISCUSSION...
ISSUED AT 632 PM CDT THU SEP 4 2014
A COLD FRONT SITUATED NEAR I-35 WILL CROSS THE TAF SITES THIS
EVENING. AS IT PASSES...THE POTENTIAL EXISTS FOR SHOWERS AND
THUNDERSTORMS TO FIRE ALONG AND JUST BEHIND IT. LSE HAS THE
GREATER PROBABILITY FOR THIS TO OCCUR...THUS LEFT THE TEMPO GROUP
FOR 02-04Z. AT RST...CONFIDENCE HAS LOWERED THAT THUNDERSTORMS
WILL AFFECT THE TAF SITE...AND THEREFORE REMOVED THE TEMPO GROUP
BUT STILL LEFT THE VCTS AS THERE COULD BE STORMS AROUND. IT
APPEARS BY 05Z MUCH OF THE SHOWER AND STORM ACTIVITY SHOULD IT
OCCUR WILL BE SOUTHEAST OF THE TAF SITES. LOOK FOR DRIER AIR
COMING IN BEHIND THE FRONT ON A 10 KT WEST TO NORTHWEST WIND TO
RESULT IN VFR CONDITIONS FOR THE OVERNIGHT HOURS INTO FRIDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...AJ
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
500 PM CDT WED SEP 3 2014
.MESOSCALE DISCUSSION...
ISSUED AT 500 PM CDT WED SEP 3 2014
CONVECTIVE EVOLUTION FOR TONIGHT REMAINS UNCERTAIN...SO PLAN ON
PROVIDING MESOSCALE DISCUSSION UPDATES THROUGHOUT THE EVENING.
ONGOING SHOWERS AND THUNDERSTORMS FROM NORTH OF ST CLOUD INTO
NORTHERN WI EXIST ON THE NOSE OF 925-850MB MOISTURE TRANSPORT...AS
WELL AS NORTH OF A WARM FRONTAL BOUNDARY SITUATED ALONG I-94.
THESE HAVE CONTINUED TO MOVE NORTHEAST THROUGH THE DAY AS A RESULT
OF PERSISTENT SOUTHERLY FLOW...AS SEEN ON KMPX VAD WIND PROFILE.
WATER VAPOR FOR THE MOST PART IS VERY NON-DESCRIPT IN TERMS OF
EASILY IDENTIFIABLE SHORTWAVES FROM THE DAKOTAS INTO OUR REGION.
THERE COULD BE ONE NEAR ABERDEEN SD AND ANOTHER NEAR OMAHA...BOTH
MOVING NORTHEAST...BUT THATS IT.
CLOSELY MONITORING TO SEE IF CONVECTION CAN DEVELOP OVER WEST-
CENTRAL MN OVER THE NEXT FEW HOURS. IF IT DOES AND CAN EVOLVE INTO
AN MCS...WHICH WOULD SEEM LIKELY GIVEN STRENGTHENING 850MB
MOISTURE TRANSPORT THROUGH THE EVENING AND PLENTIFUL
CAPE...CORFIDI VECTORS WOULD BRING IT INTO THE AREA.
OTHERWISE...SEEMS THE MAIN FOCUS FOR THE EVENING IS WATCHING THE
STRONGER CONVECTION NORTH OF ST CLOUD AND IF IT CAN MATURE INTO AN
MCS...CAUSING IT TO ROLL THROUGH LOCATIONS MAINLY ALONG/NORTH OF
I-94 LATE IN THE EVENING.
HEADING INTO THE OVERNIGHT...THE 03.20Z/21Z RAP...03.19Z/20Z HRRR
AND THE 03.18Z NAM-NEST ALL POP UP CONVECTION OVER NORTHEAST IOWA
AND SOUTHWEST WI BETWEEN MIDNIGHT AND 2 AM. THIS IS ON THE NOSE
OF A SECOND 850MB MOISTURE TRANSPORT MAXIMA COMING UP THROUGH
IOWA...LIKELY INDUCED BY THE NORMAL NOCTURNAL INCREASE AND THE TWO
SHORTWAVES APPROACHING THE AREA FROM THE WEST. WILL KEEP AN EYE ON
THIS SCENARIO THROUGH THE EVENING. SHOULD THIS SCENARIO
OCCUR...RAP SOUNDINGS SUGGEST VERY HEAVY RAIN THAT COULD RESULT IN
FLASH FLOODING AND MARGINALLY SEVERE HAIL WOULD BE THE MAIN
HAZARDS.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 350 PM CDT WED SEP 3 2014
AT 3 PM...A WARM FRONT EXTENDED FROM WOODLAKE MINNESOTA SOUTHEAST
TO FAIRFIELD IOWA /SOUTHEAST CORNER OF THE STATE/. DEW POINTS
SOUTH OF THIS FRONT WERE IN THE LOWER 70S. MEANWHILE NORTH OF THIS
FRONT DEW POINTS RANGED FROM MID 50S TO MID 60S. THE LOWEST DEW
POINTS WERE FOUND ACROSS CENTRAL WISCONSIN. THERE IS NO WEATHER
CURRENTLY ASSOCIATED WITH THIS FRONT. MEANWHILE FURTHER NORTH...A
GENERALLY WEST TO EAST BAND OF PRECIPITATION WAS LOCATED FROM
ALEXANDRIA MINNESOTA TO MERRILL WISCONSIN. THIS BAND WAS
DEVELOPING IN AN AREA OF 850 TO 700 MB FRONTOGENESIS FORCING AND
MOISTURE TRANSPORT. IN ADDITION...THERE IS A SHORT WAVE TROUGH
MOVING THROUGH NORTHERN MINNESOTA. THE LATEST RAP SUGGESTS THAT
THIS WAVE WILL TAKE THE BEST 850 TO 700 MB MOISTURE TRANSPORT
NORTH NORTHEAST TOWARD UPPER MICHIGAN THIS EVENING. MOST OF THE
MESO MODELS SUGGEST THAT THIS BAND OF PRECIPITATION WILL REMAIN
ACROSS CENTRAL MINNESOTA AND NORTHERN WISCONSIN THIS EVENING. THIS
BAND MAY POSSIBLY IMPACT TAYLOR AND CLARK COUNTIES IN NORTH-
CENTRAL WISCONSIN. THERE IS SUFFICIENT 0-6KM SHEAR FOR SUPERCELL
DEVELOPMENT INITIALLY AND THIS EVOLVES INTO A LINE AS THE COLD
POOL DEVELOPS. THE MAIN SEVERE WEATHER THREATS WOULD BE DAMAGING
WINDS AND POSSIBLY LARGE HAIL BETWEEN 04.02Z AND 04.06Z. IN
ADDITION WITH WARM CLOUD LAYERS DEPTHS AROUND 4 KM AND
PRECIPITABLE WATER AROUND 1.5 INCHES...THE STORMS WILL BE
EFFICIENT RAIN PRODUCERS. WE WILL HAVE TO WATCH CLOSELY FOR
TRAINING CELLS.
FOR THE OVERNIGHT...THERE IS QUITE A BIT OF UNCERTAINTY ON HOW
THINGS WILL EVOLVE. THE LATEST RAP SUGGESTS THAT ANOTHER WING OF
STRONG 850 MB TO 700 MB MOISTURE TRANSPORT DEVELOPS OVER NORTHEAST
IOWA AS ANOTHER SHORT WAVE /CURRENTLY OVER SOUTH DAKOTA/ MOVES
INTO THE AREA. THIS WOULD SUGGEST THE POSSIBILITY THAT ANOTHER
AREA OF SHOWERS AND STORMS WILL DEVELOP ACROSS EAST-CENTRAL
MINNESOTA AND WEST-CENTRAL WISCONSIN. LIKE ITS PREDECESSOR...THE
STORMS WOULD INITIALLY FORM AS SUPERCELLS AND THEN EVOLVE INTO
ANOTHER LINE OR LINES OF STORMS WOULD DROP SOUTH ALONG AND NORTH
ACROSS WESTERN WISCONSIN WITH A MAJORITY OF THE ACTIVITY ALONG AND
NORTH OF THE INTERSTATE 94 CORRIDOR. THIS IS ACTUALLY IN DECENT
AGREEMENT WITH WHAT THE 03.12Z NAM...ARW...AND NMM IS SHOWING IN
THEIR DETERMINISTIC SOLUTIONS. THE MAIN THREAT WOULD BE HAIL
INITIALLY AND THEN QUICKLY EVOLVE INTO A WIND THREAT AS THEY
FOLLOW THE CORFIDI VECTORS TO THE SOUTHEAST INTO THE HIGHER CAPES.
ANOTHER SCENARIO SHOWS UP IN THE SPC WRF WHERE IT TAKES THE
CURRENT LINE OF CONVECTION AND DIVES THIS SOUTH THROUGH OUR
FORECAST AREA. OVERALL PREFER THE LATTER SOLUTION...SO TRENDED THE
FORECAST TOWARD IT.
ON THURSDAY...A STRONG CAP DEVELOPS ACROSS THE AREA. 700 MB
TEMPERATURES IN THIS CAP CLIMB TO 14C. THIS IS THE STRONGEST CAP
OF THE YEAR FOR OUR AREA. BOTH THE GFS AND ECMWF SUGGEST THAT THIS
CAP WILL KEEP MOST OF THE AREA DRY FOR THIS TIME PERIOD. MEANWHILE
THE NAM SHOWS THAT A SHORT WAVE...CURRENTLY OVER COLORADO...WILL
MOVE THROUGH NORTH CENTRAL WISCONSIN DURING THE AFTERNOON. THE
LIFT ASSOCIATED WITH THIS WAVE CAUSE THIS CAP TO COOL INTO THE 8C
TO 10C RANGE. WITH MOST UNSTABLE CAPES IN THE 2 TO 4K
RANGE...THUNDERSTORMS WOULD RAPIDLY DEVELOP. THE 0-6 KM SHEAR
WOULD BE SUFFICIENT FOR SUPERCELLS INITIALLY...AND THEN QUICKLY
EVOLVE INTO A LINE AS THE 0-3KM SHEAR TAKES OVER. CONFIDENCE IN
THIS SCENARIO WAS NOT EXCEPTIONALLY HIGH...SO KEPT PRECIPITATION
CHANCES IN THE 20 TO 50 PERCENT RANGE.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 350 PM CDT WED SEP 3 2014
ON THURSDAY NIGHT...THE 03.12Z MODELS CONTINUE TO SHOW THAT A
STRONG CANADIAN COLD FRONT WILL MOVE EAST THROUGH THE FORECAST
AREA. THIS FRONT WILL BE MOVING EAST INTO 3 TO 5K MOST UNSTABLE
CAPES. THE BEST LIFT WITH THIS WAVE IS FURTHER NORTH...SO IT IS
GOING TO TAKE SOME TIME TO COOL THE CAP. SO THERE ARE SOME
QUESTIONS ACROSS SOUTHEAST MINNESOTA AND NORTHEAST IOWA ON HOW
WIDESPREAD AND HOW FAST THE STORMS WILL DEVELOP. WHILE THE 0-6KM
SHEAR IS NOT AS STRONG AS IT WILL BE TONIGHT AND ON THURSDAY...
THE 0-3 KM SHEAR WILL BE SUFFICIENT FOR SOME DAMAGING WINDS. IN
ADDITION...THE STRONG CAPES MAY ALSO AID IN THE DEVELOPMENT OF
LARGE HAIL.
ON SATURDAY NIGHT...ANOTHER SHORT WAVE TROUGH WILL MOVE THROUGH
THE AREA. WITH THE AIRMASS RATHER DRY...EXPECT THAT THIS SYSTEM
WILL JUST BRING ANOTHER REINFORCING SHOT OF COOL AIR.
FROM MONDAY NIGHT INTO TUESDAY...A LONG WAVE TROUGH WILL MOVE
THROUGH THE REGION. WHILE THE GFS HAS THIS SYSTEM NEGATIVELY
TILTED...THE BEST 0-6 KM STAYS TO OUR SOUTH. IN ADDITION...THE
TIMING OF THIS WAVE IS NOT THAT FAVORABLE FOR THAT MUCH
INSTABILITY ACROSS OUR AREA. AS A RESULT...NOT EXPECTING ANY
SEVERE WEATHER AT THIS TIME.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1245 PM CDT WED SEP 3 2014
GUSTY SOUTH WINDS ARE EXPECTED AT THE TAF SITES TODAY AS A WARM
FRONT LIFTS THROUGH THE REGION...WITH SOUTH WINDS OF 13 TO 16 KTS
WITH GUSTS AROUND 25 KTS POSSIBLE. LOOK FOR SCT TO BKN CUMULUS
THIS AFTERNOON WITH CLOUD BASES IN THE 2-4KFT RANGE. SHOWERS AND
STORMS ARE EXPECTED TO DEVELOP NORTH OF THE TAF SITES LATE THIS
AFTERNOON AND EARLY EVENING...CLOSER TO THE INTERSTATE 94
CORRIDOR NEAR THE TWIN CITIES. THESE STORMS ARE THEN EXPECTED TO
TRACK EAST/SOUTHEAST INTO PORTION OF WESTERN AND NORTHERN
WISCONSIN. AT THIS TIME THE STORMS LOOK TO STAY NORTH OF THE TAF
SITES BUT IF THEY TAKE A HARD SOUTHEAST TURN...THEY COULD IMPACT
KLSE AND POSSIBLY KRST. IF THEY WOULD MAKE IT TO THE TAF
SITES...STRONG AND GUSTY WINDS WOULD BE A POSSIBILITY. WILL HAVE
TO KEEP A VERY CLOSE EYE ON THE EVOLUTION OF THE STORMS LATE THIS
AFTERNOON INTO THIS EVENING. ANOTHER CONCERN TONIGHT WILL BE LOW
LEVEL WIND SHEAR WITH A STRONG LOW LEVEL JET SETTING UP THIS
EVENING AND PERSISTING INTO THE OVERNIGHT HOURS. PLAN ON WINDS
INCREASING TO 50 KTS AT 2KFT. THE LOW LEVEL JET WILL SUBSIDE AFTER
14Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
MESOSCALE...AJ
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
352 PM CDT WED SEP 3 2014
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 350 PM CDT WED SEP 3 2014
AT 3 PM...A WARM FRONT EXTENDED FROM WOODLAKE MINNESOTA SOUTHEAST
TO FAIRFIELD IOWA /SOUTHEAST CORNER OF THE STATE/. DEW POINTS
SOUTH OF THIS FRONT WERE IN THE LOWER 70S. MEANWHILE NORTH OF THIS
FRONT DEW POINTS RANGED FROM MID 50S TO MID 60S. THE LOWEST DEW
POINTS WERE FOUND ACROSS CENTRAL WISCONSIN. THERE IS NO WEATHER
CURRENTLY ASSOCIATED WITH THIS FRONT. MEANWHILE FURTHER NORTH...A
GENERALLY WEST TO EAST BAND OF PRECIPITATION WAS LOCATED FROM
ALEXANDRIA MINNESOTA TO MERRILL WISCONSIN. THIS BAND WAS
DEVELOPING IN AN AREA OF 850 TO 700 MB FRONTOGENESIS FORCING AND
MOISTURE TRANSPORT. IN ADDITION...THERE IS A SHORT WAVE TROUGH
MOVING THROUGH NORTHERN MINNESOTA. THE LATEST RAP SUGGESTS THAT
THIS WAVE WILL TAKE THE BEST 850 TO 700 MB MOISTURE TRANSPORT
NORTH NORTHEAST TOWARD UPPER MICHIGAN THIS EVENING. MOST OF THE
MESO MODELS SUGGEST THAT THIS BAND OF PRECIPITATION WILL REMAIN
ACROSS CENTRAL MINNESOTA AND NORTHERN WISCONSIN THIS EVENING. THIS
BAND MAY POSSIBLY IMPACT TAYLOR AND CLARK COUNTIES IN NORTH-
CENTRAL WISCONSIN. THERE IS SUFFICIENT 0-6KM SHEAR FOR SUPERCELL
DEVELOPMENT INITIALLY AND THIS EVOLVES INTO A LINE AS THE COLD
POOL DEVELOPS. THE MAIN SEVERE WEATHER THREATS WOULD BE DAMAGING
WINDS AND POSSIBLY LARGE HAIL BETWEEN 04.02Z AND 04.06Z. IN
ADDITION WITH WARM CLOUD LAYERS DEPTHS AROUND 4 KM AND
PRECIPITABLE WATER AROUND 1.5 INCHES...THE STORMS WILL BE
EFFICIENT RAIN PRODUCERS. WE WILL HAVE TO WATCH CLOSELY FOR
TRAINING CELLS.
FOR THE OVERNIGHT...THERE IS QUITE A BIT OF UNCERTAINTY ON HOW
THINGS WILL EVOLVE. THE LATEST RAP SUGGESTS THAT ANOTHER WING OF
STRONG 850 MB TO 700 MB MOISTURE TRANSPORT DEVELOPS OVER NORTHEAST
IOWA AS ANOTHER SHORT WAVE /CURRENTLY OVER SOUTH DAKOTA/ MOVES
INTO THE AREA. THIS WOULD SUGGEST THE POSSIBILITY THAT ANOTHER
AREA OF SHOWERS AND STORMS WILL DEVELOP ACROSS EAST-CENTRAL
MINNESOTA AND WEST-CENTRAL WISCONSIN. LIKE ITS PREDECESSOR...THE
STORMS WOULD INITIALLY FORM AS SUPERCELLS AND THEN EVOLVE INTO
ANOTHER LINE OR LINES OF STORMS WOULD DROP SOUTH ALONG AND NORTH
ACROSS WESTERN WISCONSIN WITH A MAJORITY OF THE ACTIVITY ALONG AND
NORTH OF THE INTERSTATE 94 CORRIDOR. THIS IS ACTUALLY IN DECENT
AGREEMENT WITH WHAT THE 03.12Z NAM...ARW...AND NMM IS SHOWING IN
THEIR DETERMINISTIC SOLUTIONS. THE MAIN THREAT WOULD BE HAIL
INITIALLY AND THEN QUICKLY EVOLVE INTO A WIND THREAT AS THEY
FOLLOW THE CORFIDI VECTORS TO THE SOUTHEAST INTO THE HIGHER CAPES.
ANOTHER SCENARIO SHOWS UP IN THE SPC WRF WHERE IT TAKES THE
CURRENT LINE OF CONVECTION AND DIVES THIS SOUTH THROUGH OUR
FORECAST AREA. OVERALL PREFER THE LATTER SOLUTION...SO TRENDED THE
FORECAST TOWARD IT.
ON THURSDAY...A STRONG CAP DEVELOPS ACROSS THE AREA. 700 MB
TEMPERATURES IN THIS CAP CLIMB TO 14C. THIS IS THE STRONGEST CAP
OF THE YEAR FOR OUR AREA. BOTH THE GFS AND ECMWF SUGGEST THAT THIS
CAP WILL KEEP MOST OF THE AREA DRY FOR THIS TIME PERIOD. MEANWHILE
THE NAM SHOWS THAT A SHORT WAVE...CURRENTLY OVER COLORADO...WILL
MOVE THROUGH NORTH CENTRAL WISCONSIN DURING THE AFTERNOON. THE
LIFT ASSOCIATED WITH THIS WAVE CAUSE THIS CAP TO COOL INTO THE 8C
TO 10C RANGE. WITH MOST UNSTABLE CAPES IN THE 2 TO 4K
RANGE...THUNDERSTORMS WOULD RAPIDLY DEVELOP. THE 0-6 KM SHEAR
WOULD BE SUFFICIENT FOR SUPERCELLS INITIALLY...AND THEN QUICKLY
EVOLVE INTO A LINE AS THE 0-3KM SHEAR TAKES OVER. CONFIDENCE IN
THIS SCENARIO WAS NOT EXCEPTIONALLY HIGH...SO KEPT PRECIPITATION
CHANCES IN THE 20 TO 50 PERCENT RANGE.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 350 PM CDT WED SEP 3 2014
ON THURSDAY NIGHT...THE 03.12Z MODELS CONTINUE TO SHOW THAT A
STRONG CANADIAN COLD FRONT WILL MOVE EAST THROUGH THE FORECAST
AREA. THIS FRONT WILL BE MOVING EAST INTO 3 TO 5K MOST UNSTABLE
CAPES. THE BEST LIFT WITH THIS WAVE IS FURTHER NORTH...SO IT IS
GOING TO TAKE SOME TIME TO COOL THE CAP. SO THERE ARE SOME
QUESTIONS ACROSS SOUTHEAST MINNESOTA AND NORTHEAST IOWA ON HOW
WIDESPREAD AND HOW FAST THE STORMS WILL DEVELOP. WHILE THE 0-6KM
SHEAR IS NOT AS STRONG AS IT WILL BE TONIGHT AND ON THURSDAY...
THE 0-3 KM SHEAR WILL BE SUFFICIENT FOR SOME DAMAGING WINDS. IN
ADDITION...THE STRONG CAPES MAY ALSO AID IN THE DEVELOPMENT OF
LARGE HAIL.
ON SATURDAY NIGHT...ANOTHER SHORT WAVE TROUGH WILL MOVE THROUGH
THE AREA. WITH THE AIRMASS RATHER DRY...EXPECT THAT THIS SYSTEM
WILL JUST BRING ANOTHER REINFORCING SHOT OF COOL AIR.
FROM MONDAY NIGHT INTO TUESDAY...A LONG WAVE TROUGH WILL MOVE
THROUGH THE REGION. WHILE THE GFS HAS THIS SYSTEM NEGATIVELY
TILTED...THE BEST 0-6 KM STAYS TO OUR SOUTH. IN ADDITION...THE
TIMING OF THIS WAVE IS NOT THAT FAVORABLE FOR THAT MUCH
INSTABILITY ACROSS OUR AREA. AS A RESULT...NOT EXPECTING ANY
SEVERE WEATHER AT THIS TIME.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1245 PM CDT WED SEP 3 2014
GUSTY SOUTH WINDS ARE EXPECTED AT THE TAF SITES TODAY AS A WARM
FRONT LIFTS THROUGH THE REGION...WITH SOUTH WINDS OF 13 TO 16 KTS
WITH GUSTS AROUND 25 KTS POSSIBLE. LOOK FOR SCT TO BKN CUMULUS
THIS AFTERNOON WITH CLOUD BASES IN THE 2-4KFT RANGE. SHOWERS AND
STORMS ARE EXPECTED TO DEVELOP NORTH OF THE TAF SITES LATE THIS
AFTERNOON AND EARLY EVENING...CLOSER TO THE INTERSTATE 94
CORRIDOR NEAR THE TWIN CITIES. THESE STORMS ARE THEN EXPECTED TO
TRACK EAST/SOUTHEAST INTO PORTION OF WESTERN AND NORTHERN
WISCONSIN. AT THIS TIME THE STORMS LOOK TO STAY NORTH OF THE TAF
SITES BUT IF THEY TAKE A HARD SOUTHEAST TURN...THEY COULD IMPACT
KLSE AND POSSIBLY KRST. IF THEY WOULD MAKE IT TO THE TAF
SITES...STRONG AND GUSTY WINDS WOULD BE A POSSIBILITY. WILL HAVE
TO KEEP A VERY CLOSE EYE ON THE EVOLUTION OF THE STORMS LATE THIS
AFTERNOON INTO THIS EVENING. ANOTHER CONCERN TONIGHT WILL BE LOW
LEVEL WIND SHEAR WITH A STRONG LOW LEVEL JET SETTING UP THIS
EVENING AND PERSISTING INTO THE OVERNIGHT HOURS. PLAN ON WINDS
INCREASING TO 50 KTS AT 2KFT. THE LOW LEVEL JET WILL SUBSIDE AFTER
14Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1108 AM CDT WED SEP 3 2014
.UPDATE...FOR SEVERE WEATHER POTENTIAL TONIGHT
ISSUED AT 1108 AM CDT WED SEP 3 2014
THE SEVERE WEATHER THREAT REMAINS ON TRACK FOR TONIGHT. SEVERE
THUNDERSTORMS ARE EXPECTED TO DEVELOP LATE THIS AFTERNOON INTO
EARLY THIS EVENING OVER PORTIONS OF CENTRAL MINNESOTA THEN TRACK
EAST INTO WISCONSIN THROUGH THE EVENING HOURS. CONFIDENCE IS THE
HIGHEST ON AREAS ALONG AND NORTH OF INTERSTATE 94 SEEING THIS
ACTIVITY. DAMAGING WINDS...LARGE HAIL...AND HEAVY RAINFALL APPEAR
THE BE THE MAIN HAZARDS. CANNOT RULE OUT AN ISOLATED TORNADO IF
THE STORMS WOULD MOVE IN DURING THE EARLY TO MID EVENING HOURS.
MESOSCALE MODELS CONTINUE TO SHOW THE BULK OF THE ACTIVITY
IMPACTING LOCATIONS NORTH OF INTERSTATE 94...IMPACTING MAINLY
CLARK AND TAYLOR COUNTIES. HOWEVER...THE 12Z NAM AND 00Z ECMWF
CONTINUE TO BRING AN MCS SOUTHEAST INTO THE FORECAST AREA FROM
THE TWIN CITIES AREA AROUND MID EVENING. IF THIS TRACK
HOLDS...LOCATIONS NORTH OF INTERSTATE 90 WOULD BE IMPACTED. WILL
HAVE TO KEEP AN EYE ON HEAVY RAIN POTENTIAL TONIGHT AS WELL WITH
PRECIPITABLE WATER VALUES INCREASING INTO THE 1.8 TO 2.0 INCH
RANGE AND WARM CLOUD DEPTHS CLIMBING TO 4.0 KM.
MOISTURE CONTINUES TO STREAM NORTHWARD THROUGH IOWA LATE THIS
MORNING WITH DEW POINTS CLIMBING INTO 70S. SO MOISTURE IS
STREAMING NORTHWARD AND WILL FUEL SEVERE THUNDERSTORM DEVELOPMENT
LATE THIS AFTERNOON INTO THIS EVENING. ONGOING STORMS THIS
MORNING OVER CENTRAL MINNESOTA SHOULD DISSIPATE AND CONTINUE TO
SHIFT NORTH INTO EARLY THIS AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 338 AM CDT WED SEP 3 2014
MAIN CONCERN FOCUSED ON SEVERE POTENTIAL TONIGHT AND AGAIN THURSDAY
NIGHT.
WATER VAPOR OR BIG PICTURE VIEW SHOWS A FAIRLY HIGH ZONAL FLOW
ACROSS THE NORTHERN CONUS. A WEAK EMBEDDED MID-LEVEL TROUGH WAS
NOTED EJECTING NORTHEAST OUT OF WY INTO WESTERN SD. AT THE
SURFACE...A WARM FRONT EXTENDED FROM SOUTHWEST SD INTO EASTERN NEB.
LIFT AHEAD OF THE WAVE AND WARM FRONT WAS PRODUCING A SMALL AREA OF
SHOWERS/THUNDERSTORMS OVER EASTERN SD/FAR SOUTHWEST MN PER LATEST
REGIONAL RADAR MOSAIC. OTHERWISE...CLOSER TO HOME...HIGH PRESSURE WAS
PRODUCING MOSTLY CLEAR SKIES ACROSS THE FORECAST AREA WITH
TEMPERATURES RANGING FROM THE LOWER 50S A NEAR 60 DEGREES.
FOR TODAY...SURFACE CYCLOGENESIS WILL CONTINUE TO TAKE SHAPE OVER
MT/NORTHERN PLAINS. THIS WILL LIFT THE AFOREMENTIONED WARM FRONT OUT
OF THE CENTRAL PLAINS INTO SOUTHERN MN. ALSO...STRENGTHENING
SOUTHERLY FLOW WILL PRODUCE INCREASING MOISTURE TRANSPORT/ISENTROPIC
LIFT INTO THE AREA. THIS IS EXPECTED TO FUEL ELEVATED AND SCATTERED
SHOWERS/THUNDERSTORMS MAINLY ALONG AND NORTH OF I-90 THROUGH THE
DAY. PLAN ON HIGHS IN THE 75-85 DEGREE RANGE.
AS WE GO INTO TONIGHT...STRENGTHENING LOW PRESSURE MOVING FROM THE
DAKOTAS INTO WESTERN MN WILL DRIVE THE WARM FRONT FARTHER
NORTHEAST...NEAR THE I-94 CORRIDOR BY MORNING. THIS IS WHERE IT GETS
COMPLICATED. 850MB MOISTURE TRANSPORTS CRANKS UP SIGNIFICANTLY WITH
VECTORS POINTED DIRECTLY INTO THE AREA. AT THE SAME TIME...STRONG
CAP SETS UP ALONG THE MISSISSIPPI RIVER AS EVIDENCED BY THE NAM/GFS
BUFKIT SOUNDINGS. EXPECTING A COMPLEX OF THUNDERSTORMS TO FIRE
SOMEWHERE ALONG I-94 BETWEEN THE TWIN CITIES AND SAINT CLOUD MN BY
THIS EVENING ON THE EDGE OF THIS CAP AND ON THE NOSE OF THE MOISTURE
TRANSPORT. FORWARD PROPAGATING CORFIDI VECTORS BRING THIS COMPLEX
SOUTHEAST AND THEN ON A MORE SOUTHERLY TRAJECTORY ONCE IT GETS EAST
OF THE MISSISSIPPI...AGAIN ON THE EDGE OF THE CAP AND IN THE
CORRIDOR OF VERY RICH MOISTURE FEED.
THIS COMPLEX WILL HAVE TO BE WATCHED CLOSELY FOR SEVERE THREAT.
EARLY ON IN THE EVENING...MODEL CONSENSUS 0-3KM MUCAPE OF 2500-
4000J/KG AND 0-6KM BULK SHEAR OF 40-50KT WILL BE SUFFICIENT FOR
SUPERCELL DEVELOPMENT MAINLY ACROSS EAST CENTRAL MN INTO NORTHWEST
WI FOR LARGE HAIL POTENTIAL...AND TORNADO THREAT IF STORMS GET
ROOTED IN THE BOUNDARY LAYER. AS MENTIONED...THEN EXPECTING THIS
THUNDERSTORM COMPLEX TO FOLLOW CORFIDI VECTORS...TAKING INTO DIRECTLY
OVER OUR AREA MAINLY EAST OF THE MISSISSIPPI RIVER TONIGHT. BY THEN
MOST OF THESE STORMS WILL BE ELEVATED IN NATURE. WITH PRECIPITABLE
WATER VALUES OF 1.5-2 INCHES OFF THE NAM AND GFS...HEAVY RAINFALL
BECOMES THE MAIN THREAT ALONG WITH DAMAGING WIND POTENTIAL. SOME
LARGE HAIL WILL ALSO BE POSSIBLE. CANNOT RULE OUT THE POSSIBILITY OF
SOME FLASH FLOODING IF THERE IS ANY REPETITIVE CONVECTION OVER NAY
ONE AREA...BUT SYSTEM SEEMS OVERALL PRETTY PROGRESSIVE IN NATURE.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 338 AM CDT WED SEP 3 2014
MODELS SHOW DEEP AREA OF LOW PRESSURE MOVING NORTH OUT OF WESTERN MN
INTO WESTERN ONTARIO BY LATE AFTERNOON. AS A RESULT...WARM FRONT WILL
PUSH NORTHEAST THROUGH THE AREA WITH A VERY WARM/HUMID/CAPPED DAY IN
STORE. HIGH TEMPERATURES ARE EXPECTED TO PUSH INTO THE 85-91 DEGREE
RANGE WITH DEW POINTS IN THE LOWER 70S. THIS WILL RESULT IN HEAT
INDICES OF 90-100.
AS THE LOW CONTINUES TO LIFT NORTHEAST INTO ONTARIO A COLD FRONT
WILL THEN PUSH THROUGH THE AREA THURSDAY NIGHT. INITIALLY THE AREA
REMAINS UNDER THE INFLUENCE OF THE STRONG CAP...BUT CONVECTION IS
EXPECTED TO EVENTUALLY FIRE IN THE EVENING AFTER 6 PM...AS THE
FRONT/ALONG WITH MID-LEVEL TROUGH MOVES IN WITH COOLING
ALOFT...WHICH SHOULD THEN BE ENOUGH TO OVERCOME THE CAP. SOME OF
THESE STORMS SHOULD BE COME SEVERE WITH DAMAGING WIND AND LARGE HAIL
BEING THE MAIN THREATS.
FOR FRIDAY INTO THE WEEKEND...
DRIER/COOLER AIR MOVES INTO THE AREA FRIDAY BEHIND THE FRONT. LOOK
FOR HIGHS IN THE UPPER 60S TO THE MIDDLE 70S.
COOL AND DRY CONDITIONS LOOK TO PERSIST THROUGH THE WEEKEND AS
CANADIAN HIGH PRESSURE DOMINATES THE MID-SECTION OF THE CONUS/UPPER
MISSISSIPPI RIVER VALLEY REGIONS. HIGHS SATURDAY AND SUNDAY STAY IN
THE UPPER 60S/LOWER 70S WITH OVERNIGHT LOWS DIPPING INTO THE 40S AND
LOWER 50S.
FOR MONDAY INTO TUESDAY...
HIGH PRESSURE DRIFTS OFF TO THE EAST AS LOW PRESSURE APPROACHES FROM
THE PLAINS. AS A RESULT...PLAN ON SHOWER/THUNDERSTORM CHANCES TO
INCREASE THROUGH THE PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 617 AM CDT WED SEP 3 2014
AREA OF ELEVATED SHOWERS AND STORMS OVER SOUTHWEST MINNESOTA IN
ASSOCIATION WITH A WEAK SHORT WAVE TROUGH. THE 03.09Z RAP SUGGESTS
THE WAVE WILL CONTINUE TO MOVE EAST TOWARD THE AREA WHILE THE MID
LEVEL MOISTURE TRANSPORT LIFTS NORTHEAST. THE 03.00Z HI-RES ARW
AND 03.09Z HRRR BOTH SUGGEST THE ACTIVITY WILL LIFT NORTHEAST WITH
THE MOISTURE TRANSPORT AND MISS BOTH TAF SITES. FEEL THE BULK OF
THE ACTIVITY SHOULD MISS THE TAF SITES BUT WILL CARRY A VCTS AT
KRST IN THE EVENT THAT THE MOVEMENT ENDS UP BEING MORE TO THE
EAST. AFTER THAT...WARM AIR ALOFT WILL RAPIDLY BUILD OVER THE AREA
TODAY PUTTING A CAP IN PLACE THAT SHOULD ALLOW THE NEXT ROUND OF
CONVECTION TO FORM NORTH OF BOTH TAF SITES LATE THIS AFTERNOON
INTO THE EVENING. ALL THE MESO MODELS SUGGEST THE ACTIVITY WILL
THEN STAY NORTH OF THE AREA THROUGH THE OVERNIGHT...BUT THE 03.00Z
ECMWF SUGGEST SOME SOUTHEAST MOVEMENT ALONG THE EDGE OF THE CAP
CLOSE TO THE BACKWARD PROPAGATING CORFIDI VECTORS. IF THIS CAN
OCCUR...THERE IS A CHANCE SOME ACTIVITY COULD MOVE DOWN THE
MISSISSIPPI RIVER INTO WESTERN WISCONSIN AND WILL CONTINUE TO
CARRY A VCTS IN THE LATE EVENING FOR THIS AT KLSE BUT THINK IT
WILL MISS KRST...IF IT CAN TURN SOUTHEAST. WITH THE STRONG LOW
LEVEL JET FEEDING INTO THE CONVECTIVE ACTIVITY...LOW LEVEL WIND
SHEAR SHOULD BE PRESENT AND HAVE INCLUDED THIS OUTSIDE OF THE
THUNDER TIME IN THE EVENING AND OVERNIGHT HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...WETENKAMP
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
618 AM CDT WED SEP 3 2014
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 338 AM CDT WED SEP 3 2014
MAIN CONCERN FOCUSED ON SEVERE POTENTIAL TONIGHT AND AGAIN THURSDAY
NIGHT.
WATER VAPOR OR BIG PICTURE VIEW SHOWS A FAIRLY HIGH ZONAL FLOW
ACROSS THE NORTHERN CONUS. A WEAK EMBEDDED MID-LEVEL TROUGH WAS
NOTED EJECTING NORTHEAST OUT OF WY INTO WESTERN SD. AT THE
SURFACE...A WARM FRONT EXTENDED FROM SOUTHWEST SD INTO EASTERN NEB.
LIFT AHEAD OF THE WAVE AND WARM FRONT WAS PRODUCING A SMALL AREA OF
SHOWERS/THUNDERSTORMS OVER EASTERN SD/FAR SOUTHWEST MN PER LATEST
REGIONAL RADAR MOSAIC. OTHERWISE...CLOSER TO HOME...HIGH PRESSURE WAS
PRODUCING MOSTLY CLEAR SKIES ACROSS THE FORECAST AREA WITH
TEMPERATURES RANGING FROM THE LOWER 50S A NEAR 60 DEGREES.
FOR TODAY...SURFACE CYCLOGENESIS WILL CONTINUE TO TAKE SHAPE OVER
MT/NORTHERN PLAINS. THIS WILL LIFT THE AFOREMENTIONED WARM FRONT OUT
OF THE CENTRAL PLAINS INTO SOUTHERN MN. ALSO...STRENGTHENING
SOUTHERLY FLOW WILL PRODUCE INCREASING MOISTURE TRANSPORT/ISENTROPIC
LIFT INTO THE AREA. THIS IS EXPECTED TO FUEL ELEVATED AND SCATTERED
SHOWERS/THUNDERSTORMS MAINLY ALONG AND NORTH OF I-90 THROUGH THE
DAY. PLAN ON HIGHS IN THE 75-85 DEGREE RANGE.
AS WE GO INTO TONIGHT...STRENGTHENING LOW PRESSURE MOVING FROM THE
DAKOTAS INTO WESTERN MN WILL DRIVE THE WARM FRONT FARTHER
NORTHEAST...NEAR THE I-94 CORRIDOR BY MORNING. THIS IS WHERE IT GETS
COMPLICATED. 850MB MOISTURE TRANSPORTS CRANKS UP SIGNIFICANTLY WITH
VECTORS POINTED DIRECTLY INTO THE AREA. AT THE SAME TIME...STRONG
CAP SETS UP ALONG THE MISSISSIPPI RIVER AS EVIDENCED BY THE NAM/GFS
BUFKIT SOUNDINGS. EXPECTING A COMPLEX OF THUNDERSTORMS TO FIRE
SOMEWHERE ALONG I-94 BETWEEN THE TWIN CITIES AND SAINT CLOUD MN BY
THIS EVENING ON THE EDGE OF THIS CAP AND ON THE NOSE OF THE MOISTURE
TRANSPORT. FORWARD PROPAGATING CORFIDI VECTORS BRING THIS COMPLEX
SOUTHEAST AND THEN ON A MORE SOUTHERLY TRAJECTORY ONCE IT GETS EAST
OF THE MISSISSIPPI...AGAIN ON THE EDGE OF THE CAP AND IN THE
CORRIDOR OF VERY RICH MOISTURE FEED.
THIS COMPLEX WILL HAVE TO BE WATCHED CLOSELY FOR SEVERE THREAT.
EARLY ON IN THE EVENING...MODEL CONSENSUS 0-3KM MUCAPE OF 2500-
4000J/KG AND 0-6KM BULK SHEAR OF 40-50KT WILL BE SUFFICIENT FOR
SUPERCELL DEVELOPMENT MAINLY ACROSS EAST CENTRAL MN INTO NORTHWEST
WI FOR LARGE HAIL POTENTIAL...AND TORNADO THREAT IF STORMS GET
ROOTED IN THE BOUNDARY LAYER. AS MENTIONED...THEN EXPECTING THIS
THUNDERSTORM COMPLEX TO FOLLOW CORFIDI VECTORS...TAKING INTO DIRECTLY
OVER OUR AREA MAINLY EAST OF THE MISSISSIPPI RIVER TONIGHT. BY THEN
MOST OF THESE STORMS WILL BE ELEVATED IN NATURE. WITH PRECIPITABLE
WATER VALUES OF 1.5-2 INCHES OFF THE NAM AND GFS...HEAVY RAINFALL
BECOMES THE MAIN THREAT ALONG WITH DAMAGING WIND POTENTIAL. SOME
LARGE HAIL WILL ALSO BE POSSIBLE. CANNOT RULE OUT THE POSSIBILITY OF
SOME FLASH FLOODING IF THERE IS ANY REPETITIVE CONVECTION OVER NAY
ONE AREA...BUT SYSTEM SEEMS OVERALL PRETTY PROGRESSIVE IN NATURE.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 338 AM CDT WED SEP 3 2014
MODELS SHOW DEEP AREA OF LOW PRESSURE MOVING NORTH OUT OF WESTERN MN
INTO WESTERN ONTARIO BY LATE AFTERNOON. AS A RESULT...WARM FRONT WILL
PUSH NORTHEAST THROUGH THE AREA WITH A VERY WARM/HUMID/CAPPED DAY IN
STORE. HIGH TEMPERATURES ARE EXPECTED TO PUSH INTO THE 85-91 DEGREE
RANGE WITH DEW POINTS IN THE LOWER 70S. THIS WILL RESULT IN HEAT
INDICES OF 90-100.
AS THE LOW CONTINUES TO LIFT NORTHEAST INTO ONTARIO A COLD FRONT
WILL THEN PUSH THROUGH THE AREA THURSDAY NIGHT. INITIALLY THE AREA
REMAINS UNDER THE INFLUENCE OF THE STRONG CAP...BUT CONVECTION IS
EXPECTED TO EVENTUALLY FIRE IN THE EVENING AFTER 6 PM...AS THE
FRONT/ALONG WITH MID-LEVEL TROUGH MOVES IN WITH COOLING
ALOFT...WHICH SHOULD THEN BE ENOUGH TO OVERCOME THE CAP. SOME OF
THESE STORMS SHOULD BE COME SEVERE WITH DAMAGING WIND AND LARGE HAIL
BEING THE MAIN THREATS.
FOR FRIDAY INTO THE WEEKEND...
DRIER/COOLER AIR MOVES INTO THE AREA FRIDAY BEHIND THE FRONT. LOOK
FOR HIGHS IN THE UPPER 60S TO THE MIDDLE 70S.
COOL AND DRY CONDITIONS LOOK TO PERSIST THROUGH THE WEEKEND AS
CANADIAN HIGH PRESSURE DOMINATES THE MID-SECTION OF THE CONUS/UPPER
MISSISSIPPI RIVER VALLEY REGIONS. HIGHS SATURDAY AND SUNDAY STAY IN
THE UPPER 60S/LOWER 70S WITH OVERNIGHT LOWS DIPPING INTO THE 40S AND
LOWER 50S.
FOR MONDAY INTO TUESDAY...
HIGH PRESSURE DRIFTS OFF TO THE EAST AS LOW PRESSURE APPROACHES FROM
THE PLAINS. AS A RESULT...PLAN ON SHOWER/THUNDERSTORM CHANCES TO
INCREASE THROUGH THE PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 617 AM CDT WED SEP 3 2014
AREA OF ELEVATED SHOWERS AND STORMS OVER SOUTHWEST MINNESOTA IN
ASSOCIATION WITH A WEAK SHORT WAVE TROUGH. THE 03.09Z RAP SUGGESTS
THE WAVE WILL CONTINUE TO MOVE EAST TOWARD THE AREA WHILE THE MID
LEVEL MOISTURE TRANSPORT LIFTS NORTHEAST. THE 03.00Z HI-RES ARW
AND 03.09Z HRRR BOTH SUGGEST THE ACTIVITY WILL LIFT NORTHEAST WITH
THE MOISTURE TRANSPORT AND MISS BOTH TAF SITES. FEEL THE BULK OF
THE ACTIVITY SHOULD MISS THE TAF SITES BUT WILL CARRY A VCTS AT
KRST IN THE EVENT THAT THE MOVEMENT ENDS UP BEING MORE TO THE
EAST. AFTER THAT...WARM AIR ALOFT WILL RAPIDLY BUILD OVER THE AREA
TODAY PUTTING A CAP IN PLACE THAT SHOULD ALLOW THE NEXT ROUND OF
CONVECTION TO FORM NORTH OF BOTH TAF SITES LATE THIS AFTERNOON
INTO THE EVENING. ALL THE MESO MODELS SUGGEST THE ACTIVITY WILL
THEN STAY NORTH OF THE AREA THROUGH THE OVERNIGHT...BUT THE 03.00Z
ECMWF SUGGEST SOME SOUTHEAST MOVEMENT ALONG THE EDGE OF THE CAP
CLOSE TO THE BACKWARD PROPAGATING CORFIDI VECTORS. IF THIS CAN
OCCUR...THERE IS A CHANCE SOME ACTIVITY COULD MOVE DOWN THE
MISSISSIPPI RIVER INTO WESTERN WISCONSIN AND WILL CONTINUE TO
CARRY A VCTS IN THE LATE EVENING FOR THIS AT KLSE BUT THINK IT
WILL MISS KRST...IF IT CAN TURN SOUTHEAST. WITH THE STRONG LOW
LEVEL JET FEEDING INTO THE CONVECTIVE ACTIVITY...LOW LEVEL WIND
SHEAR SHOULD BE PRESENT AND HAVE INCLUDED THIS OUTSIDE OF THE
THUNDER TIME IN THE EVENING AND OVERNIGHT HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...04
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1059 PM MDT TUE SEP 2 2014
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 420 PM MDT TUE SEP 2 2014
MAIN FORECAST CONCERN OVER THE NEXT FEW DAYS WILL BE THE
CRITICAL FIRE WEATHER CONDITIONS ACROSS THE CWA. IT TOOK A LITTLE
WHILE FOR RH VALUES TO DROP TO CRITICAL LEVELS THIS
AFTERNOON...BUT WE ARE CURRENTLY SEEING A RH OF AROUND 15 PERCENT
IN THE FOOTHILLS OF THE LARAMIE RANGE (FIRE WEATHER ZONES 309 AND
301). RH VALUES ARE GENERALLY 15-20 PERCENT TO THE WEST OF THE
LARAMIE RANGE. WITH GUSTS TO 25-30 MPH THROUGH EARLY
EVENING...THIS CONTINUES TO LOOK LIKE A MARGINAL RED FLAG EVENT
AND WILL KEEP THE WARNINGS GOING. CLOUD COVER THIS AFTERNOON IS
QUITE LIMITED WITH ONLY ISOLATED CUMULUS. SFC MOISTURE IS BETTER
IN SOUTHERLY WINDS JUST TO THE EAST OF THE CWA (DEUEL AND GARDEN
COUNTIES) BUT IT WILL BE TOUGH TO ADVECT THIS MOISTURE WESTWARD.
THE HRRR MODEL ALONG WITH THE OTHER MODELS DO NOT SHOW ANY QPF
OVER THE PANHANDLE TONIGHT SO WILL KEEP SLIGHT CHANE POPS OUT OF
THE FCST.
WEDNESDAY CONTINUES TO LOOK LIKE A MORE CRITICAL FIRE WEATHER DAY
OVER THE REGION. A SHORTWAVE MOVING FROM WASHINGTON INTO MONTANA
WILL INDUCE PRESSURE FALLS OVER WESTERN SOUTH DAKOTA WHICH
STRENGTHENS THE PRESSURE GRADIENT OVER ESPECIALLY SOUTHEAST WY.
MOS GUIDANCE SHOWS WINDS ABOUT 5 KTS HIGHER THAN THIS AFTN ALONG
WITH AN ADDITIONAL 5 DEGREES OF WARMING. THE FIRE WEATHER WATCH
FOR TOMORROW AFTN INCLUDES TWO ZONES (310 AND 306) THAT ARE NOT
INCLUDED IN TODAYS RED FLAG WARNING. THIS LOOKS GOOD SINCE BOTH
THESE ZONES WERE CLOSE TO HITTING THE CRITERIA TODAY AND
CONDITIONS WILL BE DRIER AND MORE BREEZY TOMORROW. THE DEEP
SOUTHWESTERLY FLOW WILL RESULT IN A VERY WARM DAY WITH HIGHS
RISING INTO THE UPPER 80S TO MID 90S ACROSS THE PLAINS. THIS COULD
BE ONE OF THE WARMEST DAYS FOR THE REST OF THE YEAR SINCE A COLD
FRONTAL PASSAGE IS STILL PROGGED FOR THURS MORNING. TEMPS WILL
DROP CLOSE TO 20 DEGREES ON THURS. STILL NO GOOD CHANCE OF PRECIP
THROUGH AT LEAST THURS EVENING. COULD BE ISOLATED SHOWERS
DEVELOPING BY THURS NIGHT ALTHOUGH THE MODEL TREND HAS BEEN TO
SHIFT THE MORE WIDESPREAD RAIN WELL TO THE SOUTH OVER NORTHWEST KS.
.LONG TERM...(FRIDAY THROUGH MONDAY NIGHT)
ISSUED AT 420 PM MDT TUE SEP 2 2014
MODELS ARE IN FAIR AGREEMENT WITH THE MEDIUM RANGE PERIOD SHOWING A
PERSISTENT QUASI-ZONAL PATTERN OVER THE CENTRAL CONUS. TEMPERATURES
WILL START OFF BELOW AVERAGE ON FRIDAY IN THE POST FRONTAL
AIRMASS...WITH THE SFC HIGH SLIDING TO THE SOUTHEAST ACROSS THE
CENTRAL PLAINS. SFC WINDS ACROSS THE HIGH PLAINS WILL BE OUT OF THE
SOUTHEAST AS THE SFC HIGH SLIDES SOUTHEAST...WITH CONVECTION
DEVELOPING OVER THE MOUNTAINS IN THE LATE AFTERNOON IN THIS LLVL
UPSLOPE REGIME. SHOULD STAY FAIRLY CAPPED ACROSS THE PLAINS WITHIN
THE COOLER AIRMASS...BUT CANT RULE OUT SHOWERS/WEAK TSTORMS
MAINTAINING AS THEY MOVE OFF THE MOUNTAINS AS A 70 KT JET AND
SHORTWAVE ENERGY WILL BE MOVING OVERHEAD AT THIS TIME. SATURDAY
LOOKS VERY SIMILAR ALBEIT WITH WEAKER UPSLOPE FLOW AND SLIGHTLY
WARMER TEMPS/HIGH INSTABILITY. SUNDAY AND MONDAY COULD SEE A BIT
MORE SUBTROPICAL MOISTURE ADVECT UP FROM THE SOUTHWEST AS A TROUGH
DIGS ALONG THE WEST COAST AND MOVES ACROSS THE GREAT BASIN. THE
DEEPEST MOISTURE LOOKS TO REMAIN TO OUR SOUTH...BUT CAN SEE SOME OF
THIS MOISTURE MAKING IT UP TO SOUTHERN PORTIONS OF THE CWA SO WILL
MAINTAIN AT LEAST SLIGHT CHANCE POPS FOR MUCH OF THE CWA. TEMPS WILL
INCREASE BACK TO MORE NORMAL VALUES FOR THIS TIME OF YEAR BY MONDAY
AS THE UPPER TROUGH DEEPENS AND A WARM AIR ADVECTION PATTERN
DEVELOPS OVER THE ROCKIES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY EVENING)
ISSUED AT 1058 PM MDT TUE SEP 2 2014
VFR CONDITIONS TO PREVAIL THRU THE PERIOD. WINDS WILL BE GENERALLY
LIGHT AT LESS THAN 10 KNOTS OVERNIGHT...BUT BECOME GUSTY AFTER 16Z
WEDNESDAY.
&&
.FIRE WEATHER...
ISSUED AT 649 PM MDT TUE SEP 2 2014
PER OUR FIRE WEATHER BRIEFING AND MODEL GUIDANCE...RED FLAG
CONDITIONS LOOKING EVEN MORE LIKELY FOR PORTIONS OF SOUTHEAST
WYOMING ON WEDNESDAY...THUS WE HAVE UPGRADED THE FIRE WEATHER
WATCH TO A RED FLAG WARNING...AND HAVE ALSO CANCELLED THE RED
FLAG WARNING THAT WAS IN EFFECT FOR THIS AFTERNOON.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING FROM NOON TO 7 PM MDT WEDNESDAY FOR WYZ301-302-
304-306-309-310.
NE...NONE.
&&
$$
SHORT TERM...FINCH
LONG TERM...RJM
AVIATION...HAHN
FIRE WEATHER...RUBIN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
417 AM EDT FRI SEP 5 2014
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 324 AM EDT FRI SEP 5 2014
VERY WARM HUMID CONDITIONS TODAY WILL COME TO AN ABRUPT END AS A
COLD FRONT TRACKS THROUGH THE REGION WITH SHOWERS AND THUNDERSTORMS
TONIGHT AND SATURDAY. HIGH PRESSURE WILL BUILD IN BEGINNING SATURDAY
NIGHT WITH DRY AND MUCH COOLER WEATHER INTO EARLY NEXT WEEK.
THUNDERSTORM CHANCES WILL RETURN TUESDAY AND CONTINUE THROUGH MUCH
OF NEXT WEEK AS A COLD FRONT MOVES THROUGH THE GREAT LAKES AND OHIO
VALLEY.
&&
.NEAR TERM /TODAY/...
ISSUED AT 324 AM EDT FRI SEP 5 2014
JUST A FEW HIGH CLOUDS DRIFTING ACROSS CENTRAL INDIANA EARLY THIS
MORNING AS REGION RESIDES UNDER THE INFLUENCE OF THE RIDGING ALOFT
CENTERED OVER THE LOWER MISSISSIPPI VALLEY EAST THROUGH THE
SOUTHEAST STATES. 07Z TEMPS RANGED FROM THE UPPER 60S TO MID 70S.
CONVECTION HAS REMAINED WELL NORTH/NORTHWEST OF THE FORECAST AREA
ALONG A COLD FRONT. MOST INTENSE STORMS ACROSS THE NORTHERN GREAT
LAKES THIS MORNING IN VICINITY OF A STRONGER SURFACE WAVE AND A
SHARPENING UPPER TROUGH. THE UPPER RIDGE WILL BUCKLE IN RESPONSE TO
THE AMPLIFYING UPPER TROUGH OVER THE UPPER MISSISSIPPI VALLEY...
ENABLING THE FRONTAL BOUNDARY TO SAG INTO THE NORTHERN FORECAST AREA
BY THIS EVENING.
AHEAD OF THE FRONT...ABUNDANT SUNSHINE AND SOUTHWEST FLOW WILL
PROVIDE FOR ANOTHER VERY WARM HUMID DAY FOR CENTRAL INDIANA. MID
LEVEL HEIGHTS WILL BEGIN TO FALL BY THE AFTERNOON AS THE FRONT
APPROACHES FROM THE NORTH AND COMBINED WITH VERY WEAK UPPER FORCING
AND A STRONGLY UNSTABLE AIRMASS...WILL INTRODUCE LOW CHANCE POPS
GRADUALLY INCREASING FROM THE NORTHWEST INTO THE EVENING. BOTH THE
WRF AND HRRR THIS MORNING APPEAR OVERDONE WITH RESPECT TO CONVECTIVE
DEVELOPMENT IN THE AFTERNOON...BUT ISOLATED STORMS CERTAINLY CANNOT
BE RULED OUT WITH THE PARAMETERS ABOVE. A LINE OF MORE ROBUST
CONVECTION IS EXPECTED TO DEVELOP THIS AFTERNOON IN THE VICINITY OF
THE FRONT OVER THE LOWER GREAT LAKES. THESE STORMS WILL BE
APPROACHING THE FORECAST AREA FROM THE NORTHWEST BY 00Z.
TEMPS...WITH 850MB TEMPS AT 20-21C AND A SOUTHWEST FLOW THIS
AFTERNOON...HAVE TRENDED TOWARDS THE WARMER MAVMOS FOR HIGHS IN THE
UPPER 80S AND LOWER 90S. MAX HEAT INDICES OF 95 TO 100 DEGREES THIS
AFTERNOON ARE EXPECTED AS WELL AND WILL HIGHLIGHT IN THE HWO.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 324 AM EDT FRI SEP 5 2014
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES THROUGH LATE SATURDAY AS
THE FRONT MOVES THROUGH THE REGION. 00Z MODEL GUIDANCE HAS GENERALLY
SLOWED THE PASSAGE OF THE BOUNDARY WITH PRECIP CHANCES LINGERING
OVER MUCH OF THE SOUTHERN HALF OF THE FORECAST AREA FOR A GOOD
PORTION OF SATURDAY.
FIRST ISSUE IS WITH EXPECTED CONVECTION MOVING INTO THE FORECAST
AREA FROM THE NORTHWEST THIS EVENING. WHILE STRONGER MID/UPPER LEVEL
FORCING AND STRONGER BL SHEAR WILL REMAIN WELL NORTH OF THE
REGION...PRESENCE OF CONVECTION MOVING INTO A STRONGLY UNSTABLE
AIRMASS WITH HIGH PRECIP WATER VALUES SHOULD BE ABLE TO COMPENSATE
FOR STORM INTENSITY MAINTENANCE INTO THE FORECAST AREA THIS EVENING.
POTENTIAL FOR A FEW OF THESE STORMS TO BE SEVERE...ESPECIALLY IF
CONVECTION CAN LAY DOWN A COLD POOL AND PROVIDE FOR AN ENHANCED
DAMAGING WIND THREAT FOR A SHORT PERIOD OF TIME. AS INSTABILITY
WANES AND THE STORMS MOVE AWAY FROM THE LIMITED BL SHEAR...SHOULD
SEE STORMS WEAKEN AND DIMINISH IN COVERAGE BY LATE EVENING SOUTH OF
I-70. WILL CARRY LIKELY POPS NORTH OF I-70 WITH LOWER POPS FURTHER
SOUTH.
THE FRONT WILL CONTINUE ITS SLOW PROGRESS SOUTH THROUGH THE FORECAST
AREA SATURDAY. MID LEVEL DEFORMATION AXIS PASSING THROUGH THE LOWER
GREAT LAKES WITH THE UPPER TROUGH WILL LINGER PRECIP CHANCES OVER
THE REGION...BUT WITH AN ABUNDANCE OF CLOUDS AND LIMITED
INSTABILITY...HARD TO JUSTIFY MUCH MORE THAN AN ISOLATED THUNDER
THREAT WITH SHOWERS. SHOWERS WILL GRADUALLY SHIFT INTO SOUTHERN
COUNTIES DURING THE AFTERNOON AS DRIER AIR ADVECTS IN FROM THE
NORTH...WITH PRECIP SOUTH OF THE REGION BY SATURDAY EVENING AS THE
FRONT MOVES INTO THE TENNESSEE VALLEY.
REMAINDER OF THE SHORT TERM WILL BE QUIET AS BROAD HIGH PRESSURE
TAKES OVER ACROSS THE MIDWEST AND OHIO VALLEY. A MUCH COOLER DRIER
AIRMASS WILL BRING A REFRESHING CHANGE FOR THE SECOND HALF OF THE
WEEKEND AND INTO EARLY NEXT WEEK.
TEMPS...MAVMOS APPEARED REASONABLE THROUGHOUT THE SHORT TERM AS
HIGHS FALL BACK INTO THE 70S BOTH SATURDAY AND SUNDAY. ONE LAST
HUMID NIGHT FOR TONIGHT WITH MUCH MORE COMFORTABLE TEMPS FOR
SATURDAY/SUNDAY NIGHTS INTO THE LOWER AND MIDDLE 50S...WITH MAYBE
EVEN A FEW RURAL LOCATIONS FALLING INTO THE UPPER 40S.
&&
.LONG TERM /MONDAY THROUGH THURSDAY NIGHT/...
ISSUED AT 342 AM EDT FRI SEP 5 2014
DRY CONDITIONS CAN BE EXPECTED ON MONDAY WITH ZONAL FLOW ALOFT AND
WEAK HIGH PRESSURE STILL AT THE SURFACE. HOWEVER...THE PATTERN WILL
QUICKLY SHIFT BY TUESDAY AS A BROAD UPPER TROUGH ENTERS THE AREA.
WIDESPREAD SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS CENTRAL
INDIANA AS EARLY AS TUESDAY MORNING...WITH INCREASING CHANCES
THROUGH THE COURSE OF THE EXTENDED PERIOD AS A COLD FRONT TRACKS
ACROSS THE AREA ON WEDNESDAY NIGHT/THURSDAY. PRECIP CHANCES WILL
TAPER OFF TOWARD THE END OF THE PERIOD...BUT WILL KEEP MENTION OF
SHOWERS AND THUNDERSTORMS IN THE FORECAST THROUGH THURSDAY NIGHT TO
ACCOUNT FOR PASSAGE OF UPPER LOW. TEMPS WILL CONTINUE TO DROP WELL
BELOW NORMAL THROUGH THE COURSE OF THE EXTENDED PERIOD WITH HIGH TEMPS
ONLY IN THE UPPER 60S/LOW 70S BY FRIDAY.
&&
.AVIATION /DISCUSSION FOR THE 05/0900Z TAF UPDATE/...
ISSUED AT 415 AM EDT FRI SEP 5 2014
UPDATE...
NO CHANGES TO KIND. DELAYED ONSET OF FOG FORMATION AT KBMG BY AN HOUR.
PREVIOUS DISCUSSION...
A COLD FRONT FROM WISCONSIN TO KANSAS IS EXPECTED TO BE NEAR LAF BY
00Z SATURDAY AND IND AND HUF AROUND 06Z SATURDAY. THUNDERSTORMS
SHOULD BE INCREASING IN COVERAGE LATE THIS AFTERNOON AND ESPECIALLY
AFTER 00Z TONIGHT. WILL GO WITH VCTS AT LAF AFTER 18Z AND THE OTHER
SITES AFTER 21Z WITH THUNDERSTORMS IN THE PREVAILING GROUP AFTER 21Z
AT LAF AND 00Z AT THE OTHER SITES. ANY CEILING SHOULD BE
VFR...EXCEPT PERHAPS IN THUNDERSTORMS THIS AFTERNOON...UNTIL THE
OVERNIGHT.
COULD SEE SOME MVFR OR WORSE FOG OVERNIGHT...ESPECIALLY AT BMG.
WOULD NOT RULE OUT A THUNDERSTORM AT LAF OVERNIGHT OR ELSEWHERE THIS
MORNING...BUT CHANCES THAT ONE WOULD HIT ANY PARTICULAR TAF SITE ARE
LOW WITH CONFIDENCE AVERAGE.
WINDS WILL PICK UP TO 10 KNOTS OR SO FROM SOUTHWEST AFTER 15Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....TDUD
AVIATION...MK/TDUD
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
343 AM EDT FRI SEP 5 2014
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 324 AM EDT FRI SEP 5 2014
VERY WARM HUMID CONDITIONS TODAY WILL COME TO AN ABRUPT END AS A
COLD FRONT TRACKS THROUGH THE REGION WITH SHOWERS AND THUNDERSTORMS
TONIGHT AND SATURDAY. HIGH PRESSURE WILL BUILD IN BEGINNING SATURDAY
NIGHT WITH DRY AND MUCH COOLER WEATHER INTO EARLY NEXT WEEK.
THUNDERSTORM CHANCES WILL RETURN TUESDAY AND CONTINUE THROUGH MUCH
OF NEXT WEEK AS A COLD FRONT MOVES THROUGH THE GREAT LAKES AND OHIO
VALLEY.
&&
.NEAR TERM /TODAY/...
ISSUED AT 324 AM EDT FRI SEP 5 2014
JUST A FEW HIGH CLOUDS DRIFTING ACROSS CENTRAL INDIANA EARLY THIS
MORNING AS REGION RESIDES UNDER THE INFLUENCE OF THE RIDGING ALOFT
CENTERED OVER THE LOWER MISSISSIPPI VALLEY EAST THROUGH THE
SOUTHEAST STATES. 07Z TEMPS RANGED FROM THE UPPER 60S TO MID 70S.
CONVECTION HAS REMAINED WELL NORTH/NORTHWEST OF THE FORECAST AREA
ALONG A COLD FRONT. MOST INTENSE STORMS ACROSS THE NORTHERN GREAT
LAKES THIS MORNING IN VICINITY OF A STRONGER SURFACE WAVE AND A
SHARPENING UPPER TROUGH. THE UPPER RIDGE WILL BUCKLE IN RESPONSE TO
THE AMPLIFYING UPPER TROUGH OVER THE UPPER MISSISSIPPI VALLEY...
ENABLING THE FRONTAL BOUNDARY TO SAG INTO THE NORTHERN FORECAST AREA
BY THIS EVENING.
AHEAD OF THE FRONT...ABUNDANT SUNSHINE AND SOUTHWEST FLOW WILL
PROVIDE FOR ANOTHER VERY WARM HUMID DAY FOR CENTRAL INDIANA. MID
LEVEL HEIGHTS WILL BEGIN TO FALL BY THE AFTERNOON AS THE FRONT
APPROACHES FROM THE NORTH AND COMBINED WITH VERY WEAK UPPER FORCING
AND A STRONGLY UNSTABLE AIRMASS...WILL INTRODUCE LOW CHANCE POPS
GRADUALLY INCREASING FROM THE NORTHWEST INTO THE EVENING. BOTH THE
WRF AND HRRR THIS MORNING APPEAR OVERDONE WITH RESPECT TO CONVECTIVE
DEVELOPMENT IN THE AFTERNOON...BUT ISOLATED STORMS CERTAINLY CANNOT
BE RULED OUT WITH THE PARAMETERS ABOVE. A LINE OF MORE ROBUST
CONVECTION IS EXPECTED TO DEVELOP THIS AFTERNOON IN THE VICINITY OF
THE FRONT OVER THE LOWER GREAT LAKES. THESE STORMS WILL BE
APPROACHING THE FORECAST AREA FROM THE NORTHWEST BY 00Z.
TEMPS...WITH 850MB TEMPS AT 20-21C AND A SOUTHWEST FLOW THIS
AFTERNOON...HAVE TRENDED TOWARDS THE WARMER MAVMOS FOR HIGHS IN THE
UPPER 80S AND LOWER 90S. MAX HEAT INDICES OF 95 TO 100 DEGREES THIS
AFTERNOON ARE EXPECTED AS WELL AND WILL HIGHLIGHT IN THE HWO.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 324 AM EDT FRI SEP 5 2014
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES THROUGH LATE SATURDAY AS
THE FRONT MOVES THROUGH THE REGION. 00Z MODEL GUIDANCE HAS GENERALLY
SLOWED THE PASSAGE OF THE BOUNDARY WITH PRECIP CHANCES LINGERING
OVER MUCH OF THE SOUTHERN HALF OF THE FORECAST AREA FOR A GOOD
PORTION OF SATURDAY.
FIRST ISSUE IS WITH EXPECTED CONVECTION MOVING INTO THE FORECAST
AREA FROM THE NORTHWEST THIS EVENING. WHILE STRONGER MID/UPPER LEVEL
FORCING AND STRONGER BL SHEAR WILL REMAIN WELL NORTH OF THE
REGION...PRESENCE OF CONVECTION MOVING INTO A STRONGLY UNSTABLE
AIRMASS WITH HIGH PRECIP WATER VALUES SHOULD BE ABLE TO COMPENSATE
FOR STORM INTENSITY MAINTENANCE INTO THE FORECAST AREA THIS EVENING.
POTENTIAL FOR A FEW OF THESE STORMS TO BE SEVERE...ESPECIALLY IF
CONVECTION CAN LAY DOWN A COLD POOL AND PROVIDE FOR AN ENHANCED
DAMAGING WIND THREAT FOR A SHORT PERIOD OF TIME. AS INSTABILITY
WANES AND THE STORMS MOVE AWAY FROM THE LIMITED BL SHEAR...SHOULD
SEE STORMS WEAKEN AND DIMINISH IN COVERAGE BY LATE EVENING SOUTH OF
I-70. WILL CARRY LIKELY POPS NORTH OF I-70 WITH LOWER POPS FURTHER
SOUTH.
THE FRONT WILL CONTINUE ITS SLOW PROGRESS SOUTH THROUGH THE FORECAST
AREA SATURDAY. MID LEVEL DEFORMATION AXIS PASSING THROUGH THE LOWER
GREAT LAKES WITH THE UPPER TROUGH WILL LINGER PRECIP CHANCES OVER
THE REGION...BUT WITH AN ABUNDANCE OF CLOUDS AND LIMITED
INSTABILITY...HARD TO JUSTIFY MUCH MORE THAN AN ISOLATED THUNDER
THREAT WITH SHOWERS. SHOWERS WILL GRADUALLY SHIFT INTO SOUTHERN
COUNTIES DURING THE AFTERNOON AS DRIER AIR ADVECTS IN FROM THE
NORTH...WITH PRECIP SOUTH OF THE REGION BY SATURDAY EVENING AS THE
FRONT MOVES INTO THE TENNESSEE VALLEY.
REMAINDER OF THE SHORT TERM WILL BE QUIET AS BROAD HIGH PRESSURE
TAKES OVER ACROSS THE MIDWEST AND OHIO VALLEY. A MUCH COOLER DRIER
AIRMASS WILL BRING A REFRESHING CHANGE FOR THE SECOND HALF OF THE
WEEKEND AND INTO EARLY NEXT WEEK.
TEMPS...MAVMOS APPEARED REASONABLE THROUGHOUT THE SHORT TERM AS
HIGHS FALL BACK INTO THE 70S BOTH SATURDAY AND SUNDAY. ONE LAST
HUMID NIGHT FOR TONIGHT WITH MUCH MORE COMFORTABLE TEMPS FOR
SATURDAY/SUNDAY NIGHTS INTO THE LOWER AND MIDDLE 50S...WITH MAYBE
EVEN A FEW RURAL LOCATIONS FALLING INTO THE UPPER 40S.
&&
.LONG TERM /MONDAY THROUGH THURSDAY NIGHT/...
ISSUED AT 342 AM EDT FRI SEP 5 2014
DRY CONDITIONS CAN BE EXPECTED ON MONDAY WITH ZONAL FLOW ALOFT AND
WEAK HIGH PRESSURE STILL AT THE SURFACE. HOWEVER...THE PATTERN WILL
QUICKLY SHIFT BY TUESDAY AS A BROAD UPPER TROUGH ENTERS THE AREA.
WIDESPREAD SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS CENTRAL
INDIANA AS EARLY AS TUESDAY MORNING...WITH INCREASING CHANCES
THROUGH THE COURSE OF THE EXTENDED PERIOD AS A COLD FRONT TRACKS
ACROSS THE AREA ON WEDNESDAY NIGHT/THURSDAY. PRECIP CHANCES WILL
TAPER OFF TOWARD THE END OF THE PERIOD...BUT WILL KEEP MENTION OF
SHOWERS AND THUNDERSTORMS IN THE FORECAST THROUGH THURSDAY NIGHT TO
ACCOUNT FOR PASSAGE OF UPPER LOW. TEMPS WILL CONTINUE TO DROP WELL
BELOW NORMAL THROUGH THE COURSE OF THE EXTENDED PERIOD WITH HIGH TEMPS
ONLY IN THE UPPER 60S/LOW 70S BY FRIDAY.
&&
.AVIATION /DISCUSSION FOR THE 05/0600Z TAF ISSUANCE/...
ISSUED AT 1240 AM EDT FRI SEP 5 2014
A COLD FRONT FROM WISCONSIN TO KANSAS IS EXPECTED TO BE NEAR LAF BY
00Z SATURDAY AND IND AND HUF AROUND 06Z SATURDAY. THUNDERSTORMS
SHOULD BE INCREASING IN COVERAGE LATE THIS AFTERNOON AND ESPECIALLY
AFTER 00Z TONIGHT. WILL GO WITH VCTS AT LAF AFTER 18Z AND THE OTHER
SITES AFTER 21Z WITH THUNDERSTORMS IN THE PREVAILING GROUP AFTER 21Z
AT LAF AND 00Z AT THE OTHER SITES. ANY CEILING SHOULD BE
VFR...EXCEPT PERHAPS IN THUNDERSTORMS THIS AFTERNOON...UNTIL THE
OVERNIGHT.
COULD SEE SOME MVFR OR WORSE FOG OVERNIGHT...ESPECIALLY AT BMG.
WOULD NOT RULE OUT A THUNDERSTORM AT LAF OVERNIGHT OR ELSEWHERE THIS
MORNING...BUT CHANCES THAT ONE WOULD HIT ANY PARTICULAR TAF SITE ARE
LOW WITH CONFIDENCE AVERAGE.
WINDS WILL PICK UP TO 10 KNOTS OR SO FROM SOUTHWEST AFTER 15Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....TDUD
AVIATION...MK
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
324 AM EDT FRI SEP 5 2014
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED
BELOW.
&&
.SYNOPSIS...
ISSUED AT 324 AM EDT FRI SEP 5 2014
VERY WARM HUMID CONDITIONS TODAY WILL COME TO AN ABRUPT END AS A
COLD FRONT TRACKS THROUGH THE REGION WITH SHOWERS AND THUNDERSTORMS
TONIGHT AND SATURDAY. HIGH PRESSURE WILL BUILD IN BEGINNING SATURDAY
NIGHT WITH DRY AND MUCH COOLER WEATHER INTO EARLY NEXT WEEK.
THUNDERSTORM CHANCES WILL RETURN TUESDAY AND CONTINUE THROUGH MUCH
OF NEXT WEEK AS A COLD FRONT MOVES THROUGH THE GREAT LAKES AND OHIO
VALLEY.
&&
.NEAR TERM /TODAY/...
ISSUED AT 324 AM EDT FRI SEP 5 2014
JUST A FEW HIGH CLOUDS DRIFTING ACROSS CENTRAL INDIANA EARLY THIS
MORNING AS REGION RESIDES UNDER THE INFLUENCE OF THE RIDGING ALOFT
CENTERED OVER THE LOWER MISSISSIPPI VALLEY EAST THROUGH THE
SOUTHEAST STATES. 07Z TEMPS RANGED FROM THE UPPER 60S TO MID 70S.
CONVECTION HAS REMAINED WELL NORTH/NORTHWEST OF THE FORECAST AREA
ALONG A COLD FRONT. MOST INTENSE STORMS ACROSS THE NORTHERN GREAT
LAKES THIS MORNING IN VICINITY OF A STRONGER SURFACE WAVE AND A
SHARPENING UPPER TROUGH. THE UPPER RIDGE WILL BUCKLE IN RESPONSE TO
THE AMPLIFYING UPPER TROUGH OVER THE UPPER MISSISSIPPI VALLEY...
ENABLING THE FRONTAL BOUNDARY TO SAG INTO THE NORTHERN FORECAST AREA
BY THIS EVENING.
AHEAD OF THE FRONT...ABUNDANT SUNSHINE AND SOUTHWEST FLOW WILL
PROVIDE FOR ANOTHER VERY WARM HUMID DAY FOR CENTRAL INDIANA. MID
LEVEL HEIGHTS WILL BEGIN TO FALL BY THE AFTERNOON AS THE FRONT
APPROACHES FROM THE NORTH AND COMBINED WITH VERY WEAK UPPER FORCING
AND A STRONGLY UNSTABLE AIRMASS...WILL INTRODUCE LOW CHANCE POPS
GRADUALLY INCREASING FROM THE NORTHWEST INTO THE EVENING. BOTH THE
WRF AND HRRR THIS MORNING APPEAR OVERDONE WITH RESPECT TO CONVECTIVE
DEVELOPMENT IN THE AFTERNOON...BUT ISOLATED STORMS CERTAINLY CANNOT
BE RULED OUT WITH THE PARAMETERS ABOVE. A LINE OF MORE ROBUST
CONVECTION IS EXPECTED TO DEVELOP THIS AFTERNOON IN THE VICINITY OF
THE FRONT OVER THE LOWER GREAT LAKES. THESE STORMS WILL BE
APPROACHING THE FORECAST AREA FROM THE NORTHWEST BY 00Z.
TEMPS...WITH 850MB TEMPS AT 20-21C AND A SOUTHWEST FLOW THIS
AFTERNOON...HAVE TRENDED TOWARDS THE WARMER MAVMOS FOR HIGHS IN THE
UPPER 80S AND LOWER 90S. MAX HEAT INDICES OF 95 TO 100 DEGREES THIS
AFTERNOON ARE EXPECTED AS WELL AND WILL HIGHLIGHT IN THE HWO.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 324 AM EDT FRI SEP 5 2014
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES THROUGH LATE SATURDAY AS
THE FRONT MOVES THROUGH THE REGION. 00Z MODEL GUIDANCE HAS GENERALLY
SLOWED THE PASSAGE OF THE BOUNDARY WITH PRECIP CHANCES LINGERING
OVER MUCH OF THE SOUTHERN HALF OF THE FORECAST AREA FOR A GOOD
PORTION OF SATURDAY.
FIRST ISSUE IS WITH EXPECTED CONVECTION MOVING INTO THE FORECAST
AREA FROM THE NORTHWEST THIS EVENING. WHILE STRONGER MID/UPPER LEVEL
FORCING AND STRONGER BL SHEAR WILL REMAIN WELL NORTH OF THE
REGION...PRESENCE OF CONVECTION MOVING INTO A STRONGLY UNSTABLE
AIRMASS WITH HIGH PRECIP WATER VALUES SHOULD BE ABLE TO COMPENSATE
FOR STORM INTENSITY MAINTENANCE INTO THE FORECAST AREA THIS EVENING.
POTENTIAL FOR A FEW OF THESE STORMS TO BE SEVERE...ESPECIALLY IF
CONVECTION CAN LAY DOWN A COLD POOL AND PROVIDE FOR AN ENHANCED
DAMAGING WIND THREAT FOR A SHORT PERIOD OF TIME. AS INSTABILITY
WANES AND THE STORMS MOVE AWAY FROM THE LIMITED BL SHEAR...SHOULD
SEE STORMS WEAKEN AND DIMINISH IN COVERAGE BY LATE EVENING SOUTH OF
I-70. WILL CARRY LIKELY POPS NORTH OF I-70 WITH LOWER POPS FURTHER
SOUTH.
THE FRONT WILL CONTINUE ITS SLOW PROGRESS SOUTH THROUGH THE FORECAST
AREA SATURDAY. MID LEVEL DEFORMATION AXIS PASSING THROUGH THE LOWER
GREAT LAKES WITH THE UPPER TROUGH WILL LINGER PRECIP CHANCES OVER
THE REGION...BUT WITH AN ABUNDANCE OF CLOUDS AND LIMITED
INSTABILITY...HARD TO JUSTIFY MUCH MORE THAN AN ISOLATED THUNDER
THREAT WITH SHOWERS. SHOWERS WILL GRADUALLY SHIFT INTO SOUTHERN
COUNTIES DURING THE AFTERNOON AS DRIER AIR ADVECTS IN FROM THE
NORTH...WITH PRECIP SOUTH OF THE REGION BY SATURDAY EVENING AS THE
FRONT MOVES INTO THE TENNESSEE VALLEY.
REMAINDER OF THE SHORT TERM WILL BE QUIET AS BROAD HIGH PRESSURE
TAKES OVER ACROSS THE MIDWEST AND OHIO VALLEY. A MUCH COOLER DRIER
AIRMASS WILL BRING A REFRESHING CHANGE FOR THE SECOND HALF OF THE
WEEKEND AND INTO EARLY NEXT WEEK.
TEMPS...MAVMOS APPEARED REASONABLE THROUGHOUT THE SHORT TERM AS
HIGHS FALL BACK INTO THE 70S BOTH SATURDAY AND SUNDAY. ONE LAST
HUMID NIGHT FOR TONIGHT WITH MUCH MORE COMFORTABLE TEMPS FOR
SATURDAY/SUNDAY NIGHTS INTO THE LOWER AND MIDDLE 50S...WITH MAYBE
EVEN A FEW RURAL LOCATIONS FALLING INTO THE UPPER 40S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 242 PM EDT THU SEP 4 2014
TEMPERATURES SHOULD BE ABOUT 5 DEGREES BELOW NORMAL THROUGH THE LONG
TERM WITH A TROUGH GENERALLY CONTROLLING THE WEATHER OVER THE
EASTERN HALF OF THE COUNTRY. THE LONG TERM WILL START OUT DRY BUT
CHANCES FOR THUNDERSTORMS WILL RETURN BY MONDAY NIGHT/TUESDAY AND
STAY THROUGH THE REST OF THE PERIOD AS WAVES MOVE THROUGH THE MAIN
TROUGH AND A FRONTAL SYSTEM SLOWLY MAKES ITS WAY THROUGH THE AREA.
MADE ONLY MINOR QUALITY CONTROL/COLLABORATION CHANGES TO THE
INITIALIZATION.
&&
.AVIATION /DISCUSSION FOR THE 05/0600Z TAF ISSUANCE/...
ISSUED AT 1240 AM EDT FRI SEP 5 2014
A COLD FRONT FROM WISCONSIN TO KANSAS IS EXPECTED TO BE NEAR LAF BY
00Z SATURDAY AND IND AND HUF AROUND 06Z SATURDAY. THUNDERSTORMS
SHOULD BE INCREASING IN COVERAGE LATE THIS AFTERNOON AND ESPECIALLY
AFTER 00Z TONIGHT. WILL GO WITH VCTS AT LAF AFTER 18Z AND THE OTHER
SITES AFTER 21Z WITH THUNDERSTORMS IN THE PREVAILING GROUP AFTER 21Z
AT LAF AND 00Z AT THE OTHER SITES. ANY CEILING SHOULD BE
VFR...EXCEPT PERHAPS IN THUNDERSTORMS THIS AFTERNOON...UNTIL THE
OVERNIGHT.
COULD SEE SOME MVFR OR WORSE FOG OVERNIGHT...ESPECIALLY AT BMG.
WOULD NOT RULE OUT A THUNDERSTORM AT LAF OVERNIGHT OR ELSEWHERE THIS
MORNING...BUT CHANCES THAT ONE WOULD HIT ANY PARTICULAR TAF SITE ARE
LOW WITH CONFIDENCE AVERAGE.
WINDS WILL PICK UP TO 10 KNOTS OR SO FROM SOUTHWEST AFTER 15Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....MK
AVIATION...MK
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1156 PM CDT THU SEP 4 2014
.UPDATE...
ISSUED AT 947 PM CDT THU SEP 4 2014
AREA RADAR MOSAIC AT 9 PM WAS SHOWING ELEVATED SHOWERS DEVELOPING
OVER FAR W CENTRAL IA INTO NE NEB...WHERE THE RAP MODEL WAS
SHOWING A WEAKENING IN THE STRONG CAP/ELEVATED MIXED LAYER WITH 14
C PLUS TEMPERATURES AT 700 MB THAT AT 00Z STRETCHED FROM NEW
MEXICO NORTHEAST THROUGH THE CENTRAL PLAINS INTO IA AND NW IL. THE
DEVELOPING CONVECTION WAS BEHIND THE SURFACE FRONT THAT EXTENDED
FROM SE MN THROUGH CHARLES CITY INTO W CENTRAL IA JUST SE OF THE
DES MOINES METRO AREA...WHERE KDMX WAS PAINTING THIS BOUNDARY WITH
A FINE LINE ECHO.
THE STRONG CAP OVERHEAD IS PROJECTED BY THE RAP TO WEAKEN AS A WEAK
SHORTWAVE APPROACHING THE MO RIVER PUSHES INTO EASTERN IA AFTER
09Z. THIS WOULD BE ALONG AND AHEAD OF THE SURFACE FRONT LIKELY TO
BE MOVING INTO EASTERN IA AT THIS TIME. 00Z 850 MB ANALYSIS
SHOWED A VERY MOIST AXIS FROM THE LOWER MS VALLEY NORTH THROUGH
CENTRAL IA AND SE MN...WITH DEWPOINTS ABOVE 16 C AHEAD OF THE COLD
FRONT. PW VALUES FROM 00Z WERE FROM 1.5 TO 1.75 IN THIS AXIS.
THE THETAE CONVERGENCE INTO ANY DEVELOPING CONVECTION...AS SHOWN
BY THE RAP...COULD LEAD TO LOCALLY HEAVY RAINFALL...ESPECIALLY IF
CONVECTION ORGANIZES AS SUGGESTED.
THIS CONVECTIVE EVOLUTION DOES NOT STRAY TOO FAR FROM THE CURRENT
FORECAST...BUT WILL BE MAKING SOME TWEAKS CLOSER TO THIS SOLUTION
IN AN UPDATE OUT SHORTLY. OUT AHEAD OF THE FRONT...WIDESPREAD
DEWPOINTS HOLDING IN THE LOWER AND MID 70S DUE TO CONTINUED
WARM ADVECTION IN THE ON THE LOW LEVEL SOUTHERLY FLOW...WILL KEEP
MINS IN THE LOWER AND POSSIBLY MID 70S IN AREAS OF THE FAR EAST
AND SOUTHEAST NOT AS LIKELY TO SEE RAINFALL OVERNIGHT.
&&
.SYNOPSIS...
ISSUED AT 327 PM CDT THU SEP 4 2014
THE CLUSTER OF THUNDERSTORMS THAT BROUGHT RAIN TO AREA OVERNIGHT
THROUGH EARLY AFTERNOON HAS SHIFTED EAST AND DISSIPATED. AFTERNOON
HEAT INDICES IN AREAS NOT IMPACTED BY THESE STORMS...GENERALLY
SOUTHWEST OF A LINE FROM DBQ TO MLI TO PRINCETON IL HAVE PUSHED
INTO THE UPPER 90S TO LOWER 100S. A COLD FRONT STRETCHES FROM A
SURFACE LOW IN NORTHWEST MN TO FSD AND INTO EASTERN NE. THUNDERSTORMS
IN MN AND NORTHERN WI ARE ASSOCIATED WITH THE WARM FRONT ALSO
EMANATING FROM THE SURFACE LOW.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 327 PM CDT THU SEP 4 2014
MAIN CONCERN IS TIMING THE COLD FRONTAL PASSAGE OVERNIGHT AND THE
ASSOCIATED PRECIP. MODELS AGREE IN BRINGING THE FRONT INTO THE
CWA AFTER 06Z THEN EXITING THE CWA FRIDAY AFTERNOON. MODELS ALSO
AGREE AMONGST EACH OTHER AND WITH CURRENT OBSERVATIONS IN THAT
PRECIP IS AND WILL BE POST FRONTAL. THUS TIMING OF THE FRONT IS
CRITICAL AND DRIVES THE PRECIP CHANCES...AS WELL AS MIN TEMPS
OVERNIGHT WHICH WILL VARY FROM POST FRONTAL IN THE NORTHWEST TO
WARM SECTOR IN THE SOUTHEAST.
AS THE FRONT SLOWS DOWN TOMORROW WITH THE SURFACE LOW WELL TO OUR
NORTH AND SOME WEAK UPPER LEVEL SUPPORT FROM THE PROGRESSIVE
TROUGH...CLOUDS AND PRECIP CHANCES WILL LINGER. I EXPECT THIS TO
BE MORE FALL-LIKE IN NATURE WITH SHOWERS AND EMBEDDED THUNDERSTORMS...
THUS NO SEVERE THREAT. WOLF
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 327 PM CDT THU SEP 4 2014
SPLENDID EARLY FALL WEATHER ARRIVING BY WEEKEND WITH MORE CHANCES OF
SHOWERS AND STORMS EARLY NEXT WEEK.
LONG TERM FORECAST CONFIDENCE...FAIR (AVERAGE) OVERALL. POOR OR BELOW
AVERAGE ON TIMING AND AMOUNTS OF RAIN EVENTS EARLY NEXT WEEK AND WITH
TIMING AND STRENGTH OF COLD TO POSSIBLY MUCH COLDER AIR ARRIVING LATE
NEXT WEEK.
OVERVIEW...INITIALIZATION AND VERIFICATION IS FAIR TO POOR WITH ONGOING
QPF FALLING TODAY AND ALSO WITH ENERGY OFF PACIFIC IMPACTING SW MONSOON
THAT MAY IMPACT AREA EARLY TO MIDDLE OF NEXT WEEK. THE AMOUNT OF LATENT
HEAT RELEASED ALSO MAY WELL IMPACT STRENGTH OF UPPER TROUGH DIVING INTO
PLAINS LATE NEXT WEEK. RUN TO RUN VARIANCES AND INTER-SOLUTION TRENDS
SUPPORTS A 70/30 BLEND OF HI- RES ECMWF WITH GEM WITH ONLY MINOR INPUTS
OF GFS AS HIGH AMOUNTS OF SW MONSOON MOISTURE APPEARS QUESTIONABLE TO
PHASE WITH FRONTAL SYSTEM WED/THU.
FRIDAY NIGHT...KEPT EVENING POPS OF MAINLY LIGHT SHOWERS AS SURFACE
FRONT SLIDES EAST WITH SUBSIDENCE SUPPORTING CLEARING ALL AREAS BETWEEN
MIDNIGHT AND SUNRISE SATURDAY AS COOL AIR MOVES IN. MINS UPPER 40S FAR
NE TO NEAR 60F FAR SE STILL REASONABLE.
SATURDAY AND SUNDAY...BEAUTIFUL EARLY FALL WEATHER AS CANADIAN HIGH
PRESSURE MOVES IN WITH LOWER 70S FOR HIGHS SATURDAY AND MOSTLY MIDDLE
70S ON SUNDAY UNDER A SUNNY SKY. DEWPOINTS IN THE UPPER 40S TO LOWER
50S ALSO SUGGEST PRISTINE EARLY FALL AIR. MINS SUNDAY AM SHOULD BE
IN THE UPPER 40S IN FAVORED LOW LYING LOCATIONS OF ROCK/WAPSI RIVER
VALLEYS AND LOWER 50S ELSEWHERE WITH MONDAY AM LOWS MAINLY IN THE
LOWER 50S. NW WINDS OF 10-20 MPH SATURDAY...BECOMING LIGHT SATURDAY
NIGHT THROUGH SUNDAY NIGHT.
MONDAY...SLIGHTLY WARMER WITH HIGHS AGAIN IN THE UPPER 70S TO AROUND
80 DEGREES SUGGESTED WITH INCREASING CLOUDS LATE AND CHANCE OF LIGHT
SHOWERS FROM THE WEST. SOUTH WINDS OF 5 TO 15 MPH BY AFTERNOON.
MONDAY NIGHT THROUGH WEDNESDAY NIGHT...UNSETTLED WITH CHANCES OF
SHOWERS AND STORMS WITH POOR CONFIDENCE OF PHASING OF MONSOON MOISTURE
AHEAD OF DEVELOPING UPPER LEVEL TROUGH. IF SKIES HAVE LESS CLOUDS
THEN HIGH TEMPERATURES MAY NEED RAISING BY UP TO 5 DEGREES FOR LATER
SHIFTS. FAVORABLE REGIME FOR MODERATE TO LOCALLY LOWER END HEAVY RAIN
AMOUNTS OVER A QUARTER INCH TO AGAIN LOCALLY OVER AN INCH PLUS ARE
SUGGESTED BY FRONTAL PASSAGE WEDNESDAY NIGHT FOR NO WATER ISSUES
SUGGESTED NOR ANY SEVERE RISK. MINS IN THE UPPER 50S TO LOWER 60S.
THURSDAY...COOLER TO POTENTIALLY MUCH COOLER AS STRONG EARLY FALL FRONT
TO PASS. FORECAST HIGHS ARE POSSIBLY 5 PLUS DEGREES TOO HIGH FOR LATER
SHIFTS TO REASSESS...OR POSSIBLY LOW/MID 60S. MINS FRIDAY MORNING AS
LOW AS THE LOW/MID 40S SUGGESTED...OR 3-5 DEGREES COLDER THAN THIS FORECAST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1155 PM CDT THU SEP 4 2014
A COLD FRONT MOVING THROUGH CENTRAL IOWA WILL PUSH SOUTHEAST
THROUGH THE TERMINALS LATE TONIGHT AND EARLY FRIDAY MORNING. THIS
WILL PROVIDE A SHIFT IN SURFACE WINDS FROM SOUTHWEST TO
NORTHWEST...ALONG WITH AT LEAST SCATTERED SHOWERS AND
THUNDERSTORMS... WHICH HAS BEEN HANDLED WITH TEMPO WORDING. THERE
IS ALSO A GOOD POTENTIAL FOR LOW CLOUDS...RESULTING IN MVFR
CONDITIONS THROUGH MUCH OF THE MORNING HOURS. SCATTERED SHOWERS
ARE POSSIBLE DURING THE AFTERNOON...BUT BETTER CHANCES APPEAR TO
BE LATE AFTERNOON AND EVENING...WHERE PROB30 WORDING HAS BEEN
UTILIZED.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...SHEETS
SYNOPSIS...WOLF
SHORT TERM...WOLF
LONG TERM...NICHOLS
AVIATION...SHEETS
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
352 AM CDT FRI SEP 5 2014
...UPDATED LONG TERM SECTION...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 100 AM CDT FRI SEP 5 2014
EVEN THOUGH WE HAVE NOT REACHED THE EQUINOX (23 SEPT 2014), WE ARE CERTAINLY
IN METEOROLOGICAL FALL AND TODAY WILL GIVE US THE FIRST DOSAGE OF FALL-
LIKE WEATHER WITH COOL TEMPERATURES, SHOWERS, CLOUDS, AND A RAW NNE/NE
WIND.
FOR THE REST OF THIS MORNING, HEAVILY BIASED THE SPATIOTEMPORAL ARRANGEMENT
OF POPS AND RESULTANT WEATHER GRIDS TO THE 4 KM NAM. THIS MODEL HAD
MORE OF A CLUE WITH INITIAL CONDITIONS THAN COMPARED TO THE OPERATIONAL
NAM AND THE WRF. RECENT HRRR GUIDANCE IS ALSO SOMEWHAT IN AGREEMENT
WITH THE 4 KM NAM AS WELL, ALBEIT, A BIT LIBERAL WITH THE EASTWARD
PROGRESSION. FOR THE BOTTOM LINE, SHOWERS AND ISOLATED THUNDERSTORMS
WILL CONTINUE TO DEVELOP ALONG THE 800-700-HPA BAROCLINIC BOUNDARY WITH
UPSLOPE/300K ISENTROPIC LIFT. BUFKIT PLUME SPREADS STILL SUPPORT A GOOD/SOAKING
RAIN WITH PRECIPITATION AMOUNTS GENERALLY IN THE 0.50-1.00" RANGE ALONG
THE SW TO NE ORIENTED BAROCLINIC BOUNDARY. THE AREA THAT WILL SEE THE
LEAST IS ACROSS SOUTH-CENTRAL KANSAS. EVENTUALLY, SUBSIDENCE AND ISENTROPIC
DOWNGLIDE WILL DEVELOP IN THE WAKE OF A PASSING SYNOPTIC WAVE. THE END
RESULT WILL BE A REDUCTION IN COVERAGE AND INTENSITY OF THE SHOWERS
LATER ON TODAY. LASTLY, SEVERE WEATHER IS NOT EXPECTED TODAY. JUST AN
OCCASIONAL LIGHTNING BOLT, BUT NOTHING ORGANIZED/SEVERE.
THE OTHER STORY FOR TODAY IS MAXIMUM TEMPERATURES. SIDED WITH THE COOLER
SOLUTION WITH MORE LOW 60SF ACROSS RAIN-COOLED AREAS AND KEPT THE WARMEST
ACROSS SOUTH-CENTRAL KANSAS, WHERE THIS AREA WILL BE IN THE WARM SECTOR
LONGER (WENT WITH AROUND 80F FOR MEDICINE LODGE).
IF SHOWERS AND ISOLATED THUNDERSTORMS DO CONTINUE THROUGH THE OVERNIGHT
HOURS, IT WOULD BE MAINLY NEAR THE OKLAHOMA BORDER AS THE BAROCLINIC
BOUNDARY SINKS SOUTH. FOR MINIMUMS, TEMPERATURES WILL FEEL THE COLDEST
IN QUITE A WHILE (LIKE SINCE LAST MAY). AS CLOUDS ERODE AND UNDER THE
INFLUENCE OF HIGH PRESSURE AND SINGLE DIGIT 850-HPA TEMPERATURES, THINK
THAT SOME AREAS (LIKE THE INTERSTATE 70 CORRIDOR) COULD SEE SOME UPPER
40SF. THE REST OF THE AREA WILL BE IN THE LOW TO MID 50SF. GOOD NIGHT
TO FINALLY OPEN UP THAT WINDOW AND BRING SOME CRISP BUT REFRESHING
FALL AIR IN AND GIVE THE AIR CONDITIONING UNIT A REST.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 348 AM CDT FRI SEP 5 2014
A TRANSITION TO A MORE FALL PATTERN, AT LEAST TEMPORARILY, IS IN
PROGRESS ON THIS SIDE OF THE HEMISPHERE WITH VIGOROUS UPPER LEVEL
TROUGHS RIPPLING THROUGH THE FLOW AND OCCASIONAL INCURSIONS OF
CANADIAN AIR INTO THE CENTRAL AND EASTERN UNITED STATES. CHALLENGES
FOR THE EXTENDED PERIOD INCLUDE THE EFFECTS OF INJECTION OF TROPICAL
MOISTURE FROM HURRICANE NORBERT ON PRECIPITATION COVERAGE EARLY NEXT
WEEK AND ANTICIPATING THE AMPLITUDE OF THE AMPLIFYING TROUGH THAT
DIGS INTO THE NORTHERN PLAINS AND SOUTHERN CANADA BY THE MIDDLE OF
NEXT WEEK.
LARGE SCALE FORCING FROM THE TROPICS REMAINS POORLY ORGANIZED.
OUTGOING LONG WAVE RADIATION SUGGESTS THAT THERE IS A WEAK COHERENT
SIGNAL THAT PROJECTS ONTO A MADDEN JULIAN OSCILLATION NEAR 140E THAT
MAY APPROACH THE DATELINE AROUND 15-16 SEPTEMBER, BUT MOST OF THE
GLOBAL MODELS SUGGEST THAT TROPICAL THUNDERSTORMS WILL REDEVELOP
BACK IN THE WESTERN INDIAN OCEAN BY MID SEPTEMBER. TEMPERATURES HAVE
BEEN ANOMALOUSLY COOL IN CENTRAL ASIA RECENTLY, AND EASTERLY FLOW
AGAINST THE MOUNTAINS IN EASTERN ASIA APPEAR TO BE CONTRIBUTING TO
THE POSTITIVE MOUNTAIN TORQUE ON THE ATMOSPHERE. RELATIVE
ATMOSPHERIC ANGULAR MOMENTUM HAS BEEN TRENDING UPWARD SLOWLY, AND
THE FLOW FOR THE NEXT WEEK OR SO IS BEST REPRESENTED BY PHASE 4 OF
THE GLOBAL WIND OSCILLATION. THIS CORRELATES WITH ANTICYCLONIC FLOW
IN THE WESTERN UNITED STATES. AS SUCH, THE IDEA OF MAINTAINING
RIDGING FROM THE SOUTHWESTERN UNITED STATES TO WESTERN CANADA NEXT
WEEK IS VERY REASONABLE. THE ECMWF CONTINUES TO BE MORE AMPLIFIED
WITH A TROUGH THAT DIGS INTO THE NORTHERN PLAINS NEXT FRIDAY THAN IS
THE GFS. SOME OF THE GFS ENSEMBLE MEMBERS ARE EVEN DEEPER AND SLOWER
WITH THE CLOSED CYCLONE THAT DEEPENS NEAR THE CANADIAN BORDER NEXT
THURSDAY THAN THE ECMWF, AND THE GEM ENSEMBLE MEMBERS EXHIBIT
CONSIDERABLE SPREAD. THE ECMWF MAY BE SLIGHTLY OVERDONE WITH THE
STRENGTH OF THE TROUGH DIGGING INTO THE NORTHERN PLAINS LATE NEXT
WEEK, BUT THE GENERAL PATTERN LOOKS GOOD. THERE WILL BE A
SIGNIFICANT INVASION OF CANADIAN AIR INTO THE CENTRAL AND NORTHERN
PART OF THE COUNTRY NEXT WEDNESDAY, AND THERE PROBABLY WILL BE
WIDESPREAD FROST AND SOME FREEZING TEMPERATURES ACROSS THE NORTHERN
PLAINS NEXT FRIDAY AND SATURDAY MORNINGS.
AFTER THE COLD AIR DRAINS SOUTHWARD NEXT WEEK, IT APPEARS LIKELY
THAT A MORE ZONAL FLOW REGIME WITH BROAD RIDGING IN THE WESTERN PART
OF THE COUNTRY WILL BECOME ESTABLISHED. TEMPERATURES WILL RETURN TO
NEAR OR ABOVE SEASONAL AVERAGES BY 16-17 SEPTEMBER, AND MOST OF THE
REST OF THE MONTH SHOULD BE FAIRLY WARM.
IN THE MORE IMMEDIATE FUTURE, SATURDAY SHOULD BE COOL WITH LIGHT
WINDS AND CLEARING SKIES AS HIGH PRESSURE BUILDS INTO THE CENTRAL
PLAINS. HIGHS IN THE LOWER HALF OF THE 70S CAN BE EXPECTED WITH H8
TEMPERATURES FROM 12 TO 15 DEGREES C. LOW LEVEL FLOW WILL RETURN TO
THE SOUTH SATURDAY NIGHT BUT WILL REMAIN LIGHT AND VARIABLE FOR MUCH
OF THE NIGHT IN CENTRAL KANSAS. TEMPERATURES WILL FALL TO NEAR 50
AGAIN IN NORTH CENTRAL KANSAS. LOWS WILL BE SOMEWHAT WARMER NEAR THE
COLORADO BORDER WHERE WARM AIR ADVECTION WILL BEGIN EARLIER IN THE
NIGHT.
PRESSURES WILL FALL IN THE NORTHERN ROCKIES AND PLAINS SATURDAY
NIGHT AND SUNDAY AS THE NEXT VIGOROUS UPPER LEVEL TROUGH APPROACHES
BRITISH COLUMBIA, AND A PLUME OF WARM AIR WILL SPREAD EAST FROM THE
ROCKIES. MID LEVEL FRONTOGENESIS LIKELY WILL SUPPORT SOME MID LEVEL
CLOUDINESS SUNDAY, AND ISENTROPIC LIFTING OVER THE RETREATING COOL
AIR MASS AS A LOW LEVEL JET DEVELOPS SUNDAY NIGHT LIKELY WILL
SUPPORT EVOLUTION OF SCATTERED NOCTURNAL ELEVATED SHOWERS AND
THUNDERSTORMS. IT IS UNCERTAIN EXACTLY HOW FAR WEST THE SHOWERS WILL
DEVELOP, BUT THE THE MOST LIKELY AREA IS EAST OF HIGHWAY 283.
MONDAY WILL BE WARM AGAIN, AND HIGH LEVEL TROPICAL MOISTURE FROM
HURRICANE NORBERT WILL BEGIN TO SPREAD INTO THE HIGH PLAINS.
THUNDERSTORMS LIKELY WILL INITIATE ALONG A CONVERGENCE ZONE FROM
NORTHWEST KANSAS INTO EASTERN COLORADO AND SPREAD EAST DURING THE
EVENING. THE GFS CARRIES THE REMNANTS OF NORBERT INTO THE CENTRAL
PART OF THE COUNTRY TUESDAY, WHILE THE ECMWF IS A LITTLE SLOWER TO
EJECT THE CARCASS. BOTH MODELS CARRY A SUBSTANTIAL INJECTION OF HIGH
LEVEL TROPICAL MOISTURE ACROSS THE CENTRAL PART OF THE COUNTRY, AND
A WEAK FRONTAL BOUNDARY IS LIKELY TO EXIST IN WESTERN KANSAS. THE
SYNOPTIC DETAILS ARE UNCERTAIN, BUT ANY CONVERGENCE ZONE WILL BE
SUFFICIENT TO SUPPORT THUNDERSTORM DEVELOPMENT.
CANADIAN AIR WILL INVADE KANSAS WEDNESDAY, AND MUCH COOLER WEATHER
WILL PREVAIL THURSDAY AND FRIDAY. A REINFORCING SURGE OF COLD AIR
WILL ARRIVE ABOUT FRIDAY. UPSLOPE FLOW AND EXTENSIVE CLOUDINESS MAY
KEEP TEMPERATURES IN THE 50S FRIDAY. RAIN CHANCES WILL DEPEND ON THE
STRENGTH OF THE UPPER LEVEL TROUGH THAT DIGS INTO THE NORTHERN PART
OF THE COUNTRY. IF THE ECMWF IS CORRECT, TEMPERATURES COULD DROP
INTO THE UPPER 30S AS FAR SOUTH AS NORTHERN KANSAS WHEN THE CLOUD
COVER FINALLY CLEARS OUT. SUCH DETAILS ARE HIGHLY UNCERTAIN THAT
FAR IN THE FUTURE, HOWEVER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1200 AM CDT FRI SEP 5 2014
NOT A GOOD TAF PD FOR VFR GA PILOTS. CIGS WILL REDUCE TO MVFR THIS
MORNING IN ASSOCIATION WITH WIDESPREAD -SHRA AND ASSOCIATED LOW
CEILINGS. CIGS MAY IMPROVE BACK TO VFR BY THIS EVENING AS SUBSIDENCE
INCREASES. WINDS WILL BE NNE/NE 8-18 KT THROUGH MUCH OF TODAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 66 50 73 53 / 80 30 10 10
GCK 63 49 73 53 / 90 30 10 10
EHA 65 51 73 54 / 80 40 10 10
LBL 70 53 74 54 / 70 40 20 10
HYS 63 49 73 50 / 80 30 10 10
P28 81 58 74 56 / 50 40 20 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SUGDEN
LONG TERM...RUTHI
AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
100 AM CDT FRI SEP 5 2014
...UPDATE TO SHORT TERM...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 100 AM CDT FRI SEP 5 2014
EVEN THOUGH WE HAVE NOT REACHED THE EQUINOX (23 SEPT 2014), WE ARE CERTAINLY
IN METEOROLOGICAL FALL AND TODAY WILL GIVE US THE FIRST DOSAGE OF FALL-
LIKE WEATHER WITH COOL TEMPERATURES, SHOWERS, CLOUDS, AND A RAW NNE/NE
WIND.
FOR THE REST OF THIS MORNING, HEAVILY BIASED THE SPATIOTEMPORAL ARRANGEMENT
OF POPS AND RESULTANT WEATHER GRIDS TO THE 4 KM NAM. THIS MODEL HAD
MORE OF A CLUE WITH INITIAL CONDITIONS THAN COMPARED TO THE OPERATIONAL
NAM AND THE WRF. RECENT HRRR GUIDANCE IS ALSO SOMEWHAT IN AGREEMENT
WITH THE 4 KM NAM AS WELL, ALBEIT, A BIT LIBERAL WITH THE EASTWARD
PROGRESSION. FOR THE BOTTOM LINE, SHOWERS AND ISOLATED THUNDERSTORMS
WILL CONTINUE TO DEVELOP ALONG THE 800-700-HPA BAROCLINIC BOUNDARY WITH
UPSLOPE/300K ISENTROPIC LIFT. BUFKIT PLUME SPREADS STILL SUPPORT A GOOD/SOAKING
RAIN WITH PRECIPITATION AMOUNTS GENERALLY IN THE 0.50-1.00" RANGE ALONG
THE SW TO NE ORIENTED BAROCLINIC BOUNDARY. THE AREA THAT WILL SEE THE
LEAST IS ACROSS SOUTH-CENTRAL KANSAS. EVENTUALLY, SUBSIDENCE AND ISENTROPIC
DOWNGLIDE WILL DEVELOP IN THE WAKE OF A PASSING SYNOPTIC WAVE. THE END
RESULT WILL BE A REDUCTION IN COVERAGE AND INTENSITY OF THE SHOWERS
LATER ON TODAY. LASTLY, SEVERE WEATHER IS NOT EXPECTED TODAY. JUST AN
OCCASIONAL LIGHTNING BOLT, BUT NOTHING ORGANIZED/SEVERE.
THE OTHER STORY FOR TODAY IS MAXIMUM TEMPERATURES. SIDED WITH THE COOLER
SOLUTION WITH MORE LOW 60SF ACROSS RAIN-COOLED AREAS AND KEPT THE WARMEST
ACROSS SOUTH-CENTRAL KANSAS, WHERE THIS AREA WILL BE IN THE WARM SECTOR
LONGER (WENT WITH AROUND 80F FOR MEDICINE LODGE).
IF SHOWERS AND ISOLATED THUNDERSTORMS DO CONTINUE THROUGH THE OVERNIGHT
HOURS, IT WOULD BE MAINLY NEAR THE OKLAHOMA BORDER AS THE BAROCLINIC
BOUNDARY SINKS SOUTH. FOR MINIMUMS, TEMPERATURES WILL FEEL THE COLDEST
IN QUITE A WHILE (LIKE SINCE LAST MAY). AS CLOUDS ERODE AND UNDER THE
INFLUENCE OF HIGH PRESSURE AND SINGLE DIGIT 850-HPA TEMPERATURES, THINK
THAT SOME AREAS (LIKE THE INTERSTATE 70 CORRIDOR) COULD SEE SOME UPPER
40SF. THE REST OF THE AREA WILL BE IN THE LOW TO MID 50SF. GOOD NIGHT
TO FINALLY OPEN UP THAT WINDOW AND BRING SOME CRISP BUT REFRESHING
FALL AIR IN AND GIVE THE AIR CONDITIONING UNIT A REST.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 321 PM CDT THU SEP 4 2014
SUNDAY AND MONDAY WILL BE MOSTLY DRY AS SURFACE HIGH PRESSURE WILL
BE LOCATED OVER THE CENTRAL PLAINS, WITH ANY PRECIPITATION WELL
TO THE SOUTH. A WEAK LEE TROUGH WILL BEGIN TO DEVELOP LATE SUNDAY
IN RESPONSE TO THE APPROACH OF A MINOR SHORTWAVE TROUGH; BUT
CURRENT THINKING IS THAT CONVECTIVE INITIATION IS NOT LIKELY DUE
TO MARGINAL LOW LEVEL MOISTURE AND LOW SURFACE BASED CAPE.
TEMPERATURES WILL BE IN A WARMING TREND DUE TO WESTERLY MID LEVEL
FLOW, LEE TROUGHING AND SOUTHERLY WINDS. BY MONDAY, THE NEXT
SHORTWAVE TROUGH WILL APPROACH, WITH INCREASING LOW LEVEL
MOISTURE. THUNDERSTORMS MAY DEVELOP IN CENTRAL AND SOUTH CENTRAL
KANSAS; AND THESE COULD BE SEVERE GIVEN MODERATE SURFACE BASED
CAPE AND VEERING WIND PROFILE. IF THE MODELS DISPLAY SOME RUN TO
RUN CONTINUITY WITH SEVERE WEATHER PARAMETERS, THEN WE WILL
MENTION POSSIBLE SEVERE IN THE HAZARDOUS WEATHER OUTLOOK IN LATER
SHIFTS. BY TUESDAY AND WEDNESDAY, UPPER LEVEL TROUGHING WILL
GRADUALLY PROGRESS FROM WESTERN CANADA INTO THE NORTHERN ROCKIES.
WITH CONTINUED LEE TROUGHING AND AVAILABLE LOW LEVEL MOISTURE,
THUNDERSTORMS ARE STILL POSSIBLE, ESPECIALLY GIVEN AN ENHANCEMENT
IN MID LEVEL MOISTURE FROM THE TROPICS AND A SURFACE FRONT
CONTRIBUTING TO LOW LEVEL CONVERGENCE. TEMPERATURES WILL DEPEND ON
THE TIMING AND COVERAGE OF PRECIPITATION, WITH HIGHS PROBABLY
REACHING AT LEAST INTO THE 80S AND POSSIBLY NEAR 90F THROUGH
TUESDAY. EVENTUALLY, AS TROUGHING CONTINUES TO AMPLIFY OVER THE
NORTHERN ROCKIES AND NORTHERN PLAINS, A STRONGER COLD FRONT WILL
ARRIVE, WITH HIGHS FALLING BACK INTO THE 60S OR 70S AS EARLY AS
FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1200 AM CDT FRI SEP 5 2014
NOT A GOOD TAF PD FOR VFR GA PILOTS. CIGS WILL REDUCE TO MVFR THIS
MORNING IN ASSOCIATION WITH WIDESPREAD -SHRA AND ASSOCIATED LOW
CEILINGS. CIGS MAY IMPROVE BACK TO VFR BY THIS EVENING AS SUBSIDENCE
INCREASES. WINDS WILL BE NNE/NE 8-18 KT THROUGH MUCH OF TODAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 50 72 53 78 / 30 10 10 10
GCK 49 72 53 78 / 30 10 10 10
EHA 51 71 54 82 / 40 20 10 10
LBL 53 71 54 80 / 40 20 10 10
HYS 49 73 53 77 / 30 0 10 10
P28 58 72 56 79 / 40 30 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SUGDEN
LONG TERM...FINCH
AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1046 PM MDT THU SEP 4 2014
.UPDATE...
ISSUED AT 850 PM MDT THU SEP 4 2014
AT 0240Z SHOWERS/THUNDERSTORMS HAVE INCREASED IN COVERAGE ALONG
AND JUST EAST OF THE CO/KS BORDER AS A WEATHER DISTURBANCE MOVES
IN FROM THE SOUTHWEST. 00Z NAM/RUC SUGGEST THAT THIS AREA OF
PRECIPITATION CONTINUES TO MOVE NORTHEAST THROUGH MIDNIGHT. IT
APPEARS PER 700-500RH THAT ANOTHER DISTURBANCE CURRENTLY OVER
SOUTHEAST COLORADO LIFTS NORTH/NORTHEAST INTO THE AREA AFTER
MIDNIGHT BRINGING HIGHER CHANCES OF RAIN AND A FEW THUNDERSTORMS
TO THE NORTHWEST 1/2-1/3 OF THE AREA. THE HRRR HAS THE HIGHER POPS
TO THE SOUTHEAST OF THIS LINE. SO...CONFIDENCE IS A BIT SHAKY AS
TO HOW THINGS DEVELOP AFTER MIDNIGHT. NO MAJOR ADJUSTMENTS MADE
THIS EVENING. DID INCREASE CLOUDINESS QUITE A BIT. OVERNIGHT LOWS
IN THE 50S STILL LOOKS GOOD AS DO THE NORTHEAST WINDS OF 10 TO 15
MPH.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 158 PM MDT THU SEP 4 2014
WV LOOP AND RAP ANALYSIS SHOWS EXPANSIVE UPPER RIDGE JUST TO OUR
SOUTHEAST WITH PLUME OF MID LEVEL MOISTURE MOVING NORTHEASTWARD
ACROSS THE SOUTHWEST CONUS IN TO THE CENTRAL ROCKIES. CIRRUS WAS
OVERSPREADING THE CENTRAL HIGH PLAINS. AHEAD OF AN EASTWARD MOVING
POSITIVELY TILTED SHORTWAVE TROUGH OVER THE NORTHERN PLAINS. A COLD
FRONT FORCED BY THE AFOREMENTIONED TROUGH HAS MADE IT THROUGH THE
FORECAST AREA AND TEMPERATURES WERE NOTICEABLY COOLER THAN 24 HOURS
PRIOR. MID TO UPPER 70S WERE COMMON IN THE NORTHWEST HALF OF THE
FORECAST AREA WHICH SAW THE EARLIEST FRONTAL PASSAGE. WINDS
IMMEDIATELY BEHIND THE FRONT GUSTED FROM THE NORTH AT 30-35 MPH BUT
HAVE SUBSIDED SOME THIS AFTERNOON. STILL...DIURNAL HEATING AND
MIXING IS CONTRIBUTING TO GUSTS APPROACHING 30 MPH. WINDS WILL
CONTINUE TO DECREASE THROUGH THE AFTERNOON...ESPECIALLY WHEN MIXING
LESSENS THIS EVENING.
CHALLENGES FOR THE SHORT TERM INCLUDE PRECIPITATION CHANCES THIS
EVENING THROUGH TOMORROW AND THE POSSIBILITY OF MARGINALLY SEVERE
HAIL WITH A FEW OF THE THUNDERSTORMS THIS EVENING. LOCALLY HEAVY
RAINFALL WILL BE POSSIBLE GIVEN PWAT VALUES APPROACHING 2 STANDARD
DEVIATIONS ABOVE CLIMO FOR EARLY SEPTEMBER. EVENT QPF TOTALS WILL BE
AROUND ONE INCH FOR THE FAR SOUTH PORTION OF THE FORECAST AREA
TAPERING TO A TENTH OF AN INCH OR LESS IN THE FAR NORTHWEST PORTION
OF THE AREA. STILL SOME UNCERTAINTY ON QPF AMOUNTS AND EXACT
PLACEMENT OF HEAVIER TOTALS ALTHOUGH SHORT RANGE GUIDANCE HAS COME
INTO BETTER AGREEMENT WITH TIMING.
SHOWERS AND THUNDERSTORMS SHOULD DEVELOP ACROSS THE SOUTHERN PORTION
OF THE AREA NEAR AND JUST NORTH OF THE FRONT LATER THIS EVENING AND
THEN CONTINUE TO DEVELOP NORTHWARD AS ISENTROPIC LIFT INCREASES ON
THE COOL SIDE OF THIS BOUNDARY. THE STRONGEST CONVECTION SHOULD
OCCUR THROUGH THE EVENING AND EARLY TONIGHT BEFORE INSTABILITY
WANES. ISOLATED MARGINALLY SEVERE HAIL SEEMS POSSIBLE GIVEN 30-40
KNOT DEEP LAYER SHEAR AND AROUND 1000 J/KG MUCAPE. THIS THREAT
SHOULD BE CONFINED TO THE SOUTHERN PORTION OF THE AREA. LATER IN THE
NIGHT SHOWERS AND THUNDERSTORMS SHOULD BECOME FAIRLY WIDESPREAD AS
ISENTROPIC LIFT MAXIMIZES OVER THE AREA...PARTICULARLY IN THE
SOUTHEASTERN PORTION WHERE HIGHER QPF AMOUNTS ARE. MODELS HAVE
TRENDED SLOWER SO ENDING TIME OF THE PRECIPITATION EVENT IS A LITTLE
UNCERTAIN BUT BY MID/LATE MORNING THE HEAVIEST PRECIPITATION WILL
HAVE SHIFTED EAST OF THE AREA. SOME SHOWERS WILL LINGER IN THE
SOUTHEAST THROUGH THE AFTERNOON BEFORE THE UPPER LEVEL TROUGH AXIS
MOVES THROUGH.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 158 PM MDT THU SEP 4 2014
FRIDAY NIGHT THERE MAYBE SOME LINGERING RAINFALL OVER THE FAR
EAST/SOUTHEAST PART OF THE AREA AHEAD OF THE DEPARTING 500MB SHORT
WAVE TROUGH. THE RAINFALL SHOULD BE EAST OF THE AREA BY MID TO LATE
EVENING. DUE TO THE LOWEST 50MB OR SO OF THE SOUNDINGS REMAINING
SATURATED THOUGHT ABOUT MENTIONING FOG IN THE FORECAST LATE FRIDAY
NIGHT. HOWEVER LOOKS LIKE THE CLOUD COVER WILL REMAIN OVER THE
AREA. IF SKIES CLEAR OVERNIGHT FOG WILL BE MUCH MORE LIKELY TO
DEVELOP. A SURFACE HIGH MOVES THROUGH THE AREA SO WINDS WILL BECOME
LIGHT AND VARIABLE. WITH A COOL AIR MASS IN PLACE LOWS WILL BE WELL
BELOW NORMAL.
SATURDAY AND SATURDAY NIGHT VERY WEAK RIPPLES IN THE UPPER LEVEL
FLOW MOVE OVER THE AREA. SOUNDINGS SHOW A CAPPED UNSATURATED
ENVIRONMENT SO THESE TWO PERIODS WILL BE DRY. DURING THE DAY THE
SURFACE HIGH MOVES EAST WHICH WILL ALLOW WARMER AIR FROM THE SOUTH
TO MOVE INTO THE AREA. SATURDAY NIGHT WILL BE A FEW DEGREES WARMER
THAN FRIDAY NIGHT.
SUNDAY THROUGH THURSDAY NUMEROUS WEAK UPPER LEVEL DISTURBANCES WILL
MOVE ACROSS THE AREA. LATEST RUN OF MODELS DISAGREES WITH THE
PROGRESSION AND LOCATION OF THE STRONGER UPPER LEVEL SHORT WAVE
TROUGH THAT WILL MOVE THROUGH MONDAY THROUGH TUESDAY...THUS LOWERING
CONFIDENCE OF WHEN/WHERE RAINFALL WILL DEVELOP. TUESDAY THROUGH
WEDNESDAY A STRONGER MORE WELL DEFINED UPPER LEVEL SHORT WAVE TROUGH
WILL MOVE THROUGH THE AREA...SO WILL HAVE HIGHER RAINFALL CHANCES AS
A RESULT. A STRONG COLD FRONT MOVES THROUGH WEDNESDAY EVENING BUT
MOISTURE AND UPPER LEVEL FORCING DO NOT LOOK VERY FAVORABLE FOR
STORM DEVELOPMENT AS THE FRONT MOVES THROUGH.
TEMPERATURES FOR THE PERIOD WILL GRADUALLY WARM THROUGH TUESDAY AS
THE COOLER AIR MASS GRADUALLY MOVES EAST. MID WEEK A STRONG COLD
FRONT MOVES INTO THE AREA WEDNESDAY NIGHT WITH THE COOLER AIR
CONTINUING TO MOVE INTO THE AREA THURSDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1045 PM MDT THU SEP 4 2014
FOR KGLD AND KMCK...VFR CONDITIONS EXPECTED THROUGH THROUGH 12Z-
14Z BEFORE MVFR AND POSSIBLY IFR CONDITIONS IN RAIN/MIST/LOW CIGS
FROM ABOUT 14Z THROUGH 02Z MOVE IN. AFTER 02Z VFR CONDITIONS
EXPECTED TO RETURN. THIS IS IN RESPONSE TO A WEATHER DISTURBANCE
AND LARGE AREA OF MOISTURE MOVING THROUGH THE AREA FROM THE
SOUTHWEST. WINDS THROUGH MUCH OF THE PERIOD GENERALLY FROM THE
NORTHEAST AT 8-12KTS. AFTER 02Z LGT/VRB WINDS EXPECTED.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...99
SHORT TERM...BRB
LONG TERM...JTL
AVIATION...99
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
235 AM CDT FRI SEP 5 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 234 AM CDT FRI SEP 5 2014
SHORT TERM CONCERNS REMAIN EXTENT OF CLOUD COVER TODAY AND
TEMPERATURE TRENDS.
SOME ISOLATED THUNDER DEVELOPED OVER NORTHERN IOWA AND LIFTED
NORTHEAST AFFECTING A SMALL PART OF SOUTH CENTRAL MN AFTER MIDNIGHT.
THIS ACTIVITY SHOULD MOVE EAST AND GRADUALLY DISSIPATE THROUGH 12Z.
THEN SHEARED UPPER TROUGH MOVES EAST SOUTHEAST DURING THE DAY.
APPEARS THERE WILL BE A FAIR AMOUNT OF MID/UPPER LEVEL CLOUDS
ASSOCIATED WITH THIS FEATURE DURING THE DAY. SHOULD REMAIN DRY WITH
THE OVERALL DRY AIRMASS IN PLACE. THIS MAY LIMIT SUNSHINE HOWEVER
AND TEMPERATURE POTENTIAL SOMEWHAT...ALONG WITH THE CAA PATTERN.
WILL LIKELY SEE SOME STRATOCUMULUS WORK INTO NORTHERN PARTS OF THE
CWA AS WELL. PREVIOUS FORECAST TEMPERATURES LOOKED GOOD AND WERE
RETAINED.
CLEARING SHOULD OCCUR EARLY EVENING AS COOL HIGH PRESSURE BUILDS
EAST. TEMPERATURES EXPECTED TO COOL THROUGH THE MID 40S TO AROUND
50 WITH LIGHT WIND.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 234 AM CDT FRI SEP 5 2014
QUIET WEATHER WILL CONTINUE THROUGH EARLY NEXT WEEK WITH HIGH
PRESSURE DRIFTING ACROSS THE MID MISSOURI VALLEY SATURDAY...THE
MID MISSISSIPPI VALLEY SUNDAY AND THE LOWER GREAT LAKES/NEW
ENGLAND BY MONDAY MORNING. WEAK WAA WILL BRING SLOWLY MODERATING
TEMPS EACH DAY. CLEAR SKIES ARE EXPECTED.
MODELS ARE BEGINNING TO BACK OFF ON PRECIPITATION WITH THE SHORT
WAVE MONDAY AND MONDAY NIGHT. DESPITE THE DISTURBANCE PROPAGATING
OVERHEAD...MOISTURE APPEARS TO BE LACKING WITH TRAJECTORIES
ORIGINATING FROM THE HIGH PRESSURE SYSTEM AND MOST OF THE
PRECIPITATION LOOKS TO REMAIN SOUTH ACROSS MISSOURI AND IOWA.
CONTINUED TO REDUCE POPS SOME...WITH THE HIGHEST ACROSS SOUTHERN
MN.
THE PATTERN WILL BECOME MORE AMPLIFIED DURING THE MIDDLE OF NEXT
WEEK AS A TROUGH BEGINS TO DIG INTO THE NORTHERN ROCKIES AND
NORTHERN PLAINS. WITH THICKNESS PACKING SAGGING SOUTH AND MOISTURE
FROM HURRICANE NORBERT IN THE EASTERN PACIFIC BEING ADVECTED
NORTHEAST...IT WILL BE INTERESTING TO SEE HOW A SURFACE CYCLONE
DEVELOPS TO THE LEE OF THE ROCKIES. GFS AND ECMWF APPEAR TO BE IN
PRETTY GOOD AGREEMENT AT THIS RANGE WITH A LARGE AND INTENSIFYING
CYCLONE TRACKING FROM THE PANHANDLE REGION INTO THE GREAT LAKES BY
WEDNESDAY NIGHT/THURSDAY. THERE WILL BE MULTIPLE CHANCES FOR
PRECIPITATION DURING THIS PERIOD WITH THE FIRST BEING THE
PRECEDING SHORT WAVE...THE SECOND WITH THE COLD FRONT AND DIGGING
TROUGH...AND THE THIRD WITH THE DEFORMATION/INVERTED TROUGH
STRATIFORM RAIN ASSOCIATED WITH THE CYCLONE LATE WEEK.
FOLLOWING THAT SYSTEM...TEMPERATURES WILL DROP WELL BELOW AVERAGE.
HIGHS MAY ONLY BE IN THE 50S...AND LOWS COULD FALL INTO THE 30S
WITH AN EARLY SEASON FROST POSSIBLE JUST BEYOND THE CURRENT
FORECAST PERIOD AS SUB-540DM THICKNESSES AND STRONG SURFACE HIGH
PRESSURE MOVE IN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1052 PM CDT THU SEP 4 2014
THE PRIMARY CONCERN THIS TAF PERIOD IS THE POTENTIAL FOR MVFR CIGS
OVERNIGHT AND FRIDAY MORNING AS A LOBE OF LLVL MOISTURE SWINGS
DOWN ACROSS CENTRAL MN AND WEST CENTRAL WI. THE HIGHEST
PROBABILITY OF A BKN-OVC MVFR DECK IS AT KAXN AND KSTC...CLOSER TO
THE BETTER FETCH OF MOISTURE. HAVE INCLUDED SCT MVFR LEVEL CLOUDS
AT KMSP ON FRIDAY MORNING...AND BKN AT KRNH AND KEAU WHERE 0.5
KMAGL RAP CONDENSATIONAL PRESSURE DEFICITS DECREASE TO BETWEEN 10
AND 20 MB. THEN NORTHWEST WINDS AND DRIER AIR WORK INTO THE AREA
THROUGHOUT THE DAY AND CONTRIBUTE TO SCATTERING LOW CLOUDS BY THE
AFTERNOON WITH ONLY A SCT-BKN HIGH DECK REMAINING. SHOULD THEN SEE
CLEARING ON FRIDAY EVENING. NORTHWEST WINDS CIRCA 8-12KTS PREVAIL
THROUGH FRIDAY...WITH GUSTS INTO THE MID/UPPER TEENS DURING THE
DAYTIME. SPEEDS REDUCE TO AOB 5 KTS ON FRIDAY EVE AND BACK TO
WEST/SOUTHWEST IN DIRECTION.
KMSP...
HAVE KEPT A MENTION OF SCT 2500 FT CLOUDS ON FRIDAY MORNING...BUT
OTHERWISE VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD WITH SCT-
BKN HIGH CLOUDS UNTIL CLEARING COMMENCES AFTER 00Z SAT. NORTHWEST WINDS AT
AROUND 11KTS ON FRIDAY GUST TO AROUND 17 KTS DURING THE AFTERNOON...THEN
DECREASE BELOW 7 KTS FRIDAY EVE.
/OUTLOOK FOR KMSP/
SAT...VFR. WINDS W 5-10 KTS.
SUN...VFR. WINDS SW 5-10 KTS.
MON...MAINLY VFR. CHC MVFR IN SHRA/TSRA. WINDS S 10-15 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...DWE
LONG TERM...BORGHOFF
AVIATION...LS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1153 PM CDT THU SEP 4 2014
.SHORT TERM...(TONIGHT THROUGH SUNDAY)
ISSUED AT 310 PM CDT THU SEP 4 2014
CHANCE FOR SHOWERS AND STORMS TONIGHT...AND COOLER TEMPERATURES TO
FOLLOW...ARE THE PRIMARY SHORT RANGE FORECAST CONCERNS.
COLD FRONT WAS SLIPPING SOUTHEAST THROUGH THE CWA THIS AFTERNOON.
LATEST RAP ANALYSIS SHOWS INSTABILITY INCREASING AHEAD OF THE FRONT
WHERE MLCAPES WERE OVER 3000 J/KG ACROSS SOUTHEAST NEBRASKA AND
SOUTHWEST IOWA. HOWEVER WARM MID LEVEL TEMPERATURES WERE PROVIDING A
CAP FOR STORMS AHEAD OF THE FRONT. BEHIND THE FRONT SCATTERED
SHOWERS AND STORMS HAD DEVELOPED IN SOUTHEAST SOUTH DAKOTA TIED TO
WAVE RIDING THROUGH THE NORTHERN PLAINS...BUT THOSE HAD MOVED OFF TO
THE NORTHEAST OR HAD DISSIPATED BY MID AFTERNOON. GIVEN CAPPING
ALONG AND AHEAD OF FRONT...SEEMS UNLIKELY WE WILL SEE DEVELOPMENT
THERE THIS AFTERNOON OR EVENING. BEHIND THE FRONT...MORE DEVELOPMENT
WILL HAVE TO WAIT UNTIL SHORTWAVE CURRENTLY MOVING INTO EASTERN
COLORADO MOVES INTO OUR AREA. LATEST SHORT RANGE MESOSCALE MODELS
SUGGEST THIS WILL NOT HAPPEN UNTIL LATE THIS EVENING...AND FOCUS ON
AREAS NEAR AND NORTHWEST OF INTERSTATE 80...WITH A GRADUAL DRIFT AND
EXPANSION TO THE SOUTHEAST DURING THE OVERNIGHT.
STRONGER MID LEVEL SHORTWAVE PROVIDING MID LEVEL FRONTOGENESIS IS
FORECAST TO OVERSPREAD THE REGION FRIDAY AFTERNOON AND EVENING
BEFORE MOVING OFF TO THE EAST FRIDAY NIGHT. WILL CONTINUE CHANCE FOR
SHOWERS MUCH OF FRIDAY WITH DECREASING CHANCES FRIDAY NIGHT.
SURFACE HIGH PRESSURE WITH NORTHWEST FLOW ALOFT WILL THEN TAKE OVER
AND BRING MILD AND DRY WEATHER FOR THE BULK OF THE WEEKEND. RETURN
FLOW SETTING UP ON SUNDAY COULD SPREAD MORE CLOUDS INTO THE
REGION...BUT WILL KEEP PRECIPITATION OUT OF THE FORECAST THROUGH THE
AFTERNOON.
COOLER WEATHER IS ALSO ON TAP FOR THE WEEKEND. TEMPERATURES AHEAD OF
COLD FRONT WERE IN THE 90S THIS AFTERNOON...WITH 70S OR EVEN 60S
NOTED IN SOUTH DAKOTA IN DEEPER COLD AIR BEHIND THE FRONT
CORRESPONDING TO 10C 850 TEMPERATURES. THAT AIR WILL SETTLE OVER OUR
AREA FRIDAY AND SATURDAY BEFORE WARMING TO NEAR 14C ON SUNDAY. MODEL
OUTPUT AGREES WITH OUR GOING FORECAST FOR UPPER 60S TO LOWER 70S
FRIDAY AND SATURDAY...WITH MID 70S OR SO ON SUNDAY. SEE NO REASON TO
MOVE FROM THOSE NUMBERS TOO MUCH.
.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 310 PM CDT THU SEP 4 2014
UPPER LEVEL FLOW PATTERN WILL BECOME MORE ZONAL FOR THE FIRST HALF
OF THE WEEK BEFORE LARGE UPPER TROUGH SETTLES INTO THE CONUS FOR THE
LATTER HALF. STRONG SHORTWAVE MOVING THROUGH THE PLAINS WILL BRING
RAIN CHANCES TO OUR AREA SUNDAY NIGHT THROUGH MONDAY BEFORE EJECTING
EAST MONDAY NIGHT. RETURN FLOW BEGINNING SUNDAY WILL PROVIDE PLENTY
OF MOISTURE FOR STORMS MONDAY AFTERNOON WHEN SURFACE-BASED CAPES
SHOULD TOP 2000 J/KG AND BULK 0-6KM SHEAR OVER 40KT. SEVERE STORMS
ARE POSSIBLE MONDAY AFTERNOON IF STORMS DO FIRE.
WITH WAVE EXITING TUESDAY...WE SHOULD SEE A DRY PERIOD UNTIL HEIGHTS
BEGIN TO LOWER WEDNESDAY WITH APPROACH OF DEEPER UPPER TROUGH
SETTLING INTO THE PLAINS. CORE OF UPPER TROUGH/LOW WILL MOVE INTO
THE NORTHERN PLAINS BY THURSDAY...AND WILL DRIVE A COLD FRONT
THROUGH OUR AREA WEDNESDAY. ANOTHER CHANCE FOR THUNDERSTORMS WILL
ACCOMPANY THAT FRONT...THEN MAINLY SHOWERS IN OVERRUNNING REGIME
BEHIND THE FRONT FOR WEDNESDAY NIGHT INTO THURSDAY.
TEMPERATURES WILL BE SLOWLY WARMING AHEAD OF WEDNESDAY COLD
FRONT...WITH HIGHS BETWEEN 75 AND 85...THEN MUCH COOLER THURSDAY
WITH HIGHS IN THE 60S.
&&
.AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1149 PM CDT THU SEP 4 2014
AVIATION CONCERNS WILL CONTINUE TO BE SHRA/TSRA. TSRA SHOULD
CONTINUE TO BE SOUTH OF KOFK THROUGH TONIGHT...AND WILL INCLUDE
SHRA/TSRA MENTION AT KOMA AND KLNK INTO THE EARLY MORNING HOURS.
RAIN CHANCES WILL CONTINUE FRIDAY...HOWEVER FOR NOW INCLUDED A
PROB30 AT KOFK LATER FRIDAY MORNING AS ANOTHER SHORTWAVE EMBEDDED
IN THE FLOW AFFECTS THE AREA AND BETWEEN 18 AND 21Z AT KOMA AND
KLNK. SOME OF THE MODELS ARE HINTING AS SOME PATCHY MVFR CIGS
AFTER 18Z...SO WILL NEED TO WATCH THIS. NORTH WINDS 6 TO 12KTS
TONIGHT AND THEN 8 TO 14KTS DURING THE DAY FRIDAY.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...DERGAN
LONG TERM...DERGAN
AVIATION...ZAPOTOCNY
AREA FORECAST DISCUSSION
NWS RALEIGH NC
345 AM EDT FRI SEP 5 2014
.SYNOPSIS...HIGH PRESSURE ALOFT WILL EXTEND ACROSS CENTRAL NC
THROUGH SATURDAY. A COLD FRONT WILL CROSS THE AREA SATURDAY
NIGHT AND STALL TO OUR SOUTH ON SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 315 AM FRIDAY...
THE SUB-TROPICAL RIDGE HOLDS ON ACROSS THE SOUTHEAST US FOR ANOTHER
DAY...AS THE BERMUDA HIGH BUILDS WESTWARD ACROSS THE REGION. THE
WEAK FRONTAL ZONE NEAR THE NC/VA BORDER ON THURSDAY HAS ESSENTIALLY
WASHED OUT...LEAVING MAINLY THE SEABREEZE AND TERRAIN INDUCED
DIFFERENTIAL HEATING AS THE PRIMARY TRIGGERS FOR CONVECTION TODAY.
WHILE NOT A PROMINENT ON RADAR AS WAS THE CASE YESTERDAY...LINGERING
OUTFLOW BOUNDARIES MAY ALSO TRIGGER SOME CONVECTION. THE HRRR SHOWS
SOME LATE MORNING SHOWERS OVER THE NORTHWEST PIEDMONT...WHICH SEEMS
SOMEWHAT REASONABLE GIVEN THAT IT WAS ONE OF THE LAST PLACES TO HAVE
SHOWERS THIS MORNING. MODERATE INSTABILITY OF 1000-2000 J/KG MLCAPE
SHOULD DEVELOP THIS AFTERNOON...BUT WITH VERY WEAK
SHEAR...CONVECTION IS NOT EXPECTED TO BE PARTICULARLY INTENSE.
WILL MOSTLY MAINTAIN THE PREVIOUS FORECAST POPS OF CHANCES IN THE
NORTHWEST AND SOUTHEAST...WITH A SLIGHT CHANCE OVER THE NORTHWEST
PIEDMONT AREA THIS MORNING GIVEN THE REASONING ABOVE. HIGHS AROUND
90 DEGREES.
&&
.SHORT TERM /SATURDAY AND SATURDAY NIGHT/...
AS OF 320 AM FRIDAY...
SAT AND SAT NIGHT: ONE MORE DAY OF HEAT...IN ADVANCE OF A COLD FRONT
FORECAST TO SETTLE SOUTHEASTWARD TO A POSITION FROM EASTERN NEW
ENGLAND TO THE CENTRAL AND SOUTHERN APPALACHIANS BY SAT EVENING. A
PRE-FRONTAL TROUGH AND THE SEA-BREEZE WILL FOCUS INITIALLY DIURNAL
HEATING-DRIVEN AFTERNOON AND EVENING CONVECTION OVER THE
NORTHWESTERN AND SOUTHERN PORTIONS OF THE RAH CWFA...WITH THE LATTER
POSSIBLY ENHANCED BY THE SLOW NORTHWARD DRIFT OF AN AREA OF
DISTURBED WEATHER FORECAST TO DRIFT NORTH FROM THE EAST COAST OF FL
TO EASTERN GA AND SC. SHOWERS AND STORMS WILL LIKELY PERSIST
THROUGHOUT THE NIGHT...PARTICULARLY NORTH OF THE SANDHILLS AND
SOUTHERN COASTAL PLAIN...AS THE AFOREMENTIONED COLD FRONT OVERTAKES
THE PRE-FRONTAL TROUGH OVER NORTHERN AND CENTRAL NC OVERNIGHT. LOWS
IN THE MIDDLE TO UPPER 60S IN DEVELOPING POST-FRONTAL CAA OVER THE
NORTHERN PIEDMONT...TO LOWER 70S OVER THE WARM SECTOR IN THE
SANDHILLS AND SOUTHERN COASTAL PLAIN.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 340 AM FRIDAY...
SUN: THE COLD FRONT...WHOSE TIMING HAS SLOWED VERSUS THE FASTER
TREND IN NWP GUIDANCE NOTED YESTERDAY...IS NOW FORECAST TO ROUGHLY
BISECT CENTRAL NC FROM NW TO SE AT THE START OF THE DAY SUN...THEN
ONLY SLOWLY DRIFT SOUTHEASTWARD THROUGHOUT THE DAY. THE RESULT WILL
BE NUMEROUS TO WIDESPREAD SHOWERS AND STORMS OVER A LARGER PART OF
THE CWFA...OVER ALL BUT THE FAR NORTHERN AND NW PIEDMONT WHERE POP
WILL BE IN THE CHANCE RANGE...THROUGH THE AFTERNOON. NOT AS
WARM...WITH HIGHS IN THE LOWER 80S NW...TO UPPER 80S TOWARD KFAY-
KGSB-KCTZ. IN AN ENVIRONMENT CHARACTERIZED BY PRECIPITABLE WATER
VALUES NEAR TWO INCHES...FLOODING IN URBAN AND OTHER FLOOD PRONE
AREAS WILL BE POSSIBLE.
SUN NIGHT-MON NIGHT: THE FRONT IS THEN FORECAST TO SLOW AS IT INTO
EASTERN NC (NOT AS FAR EAST AS EARLIER PROGGED). FRONTAL CONVERGENCE
AND INVOF A WAVE OR TWO OF LOW PRESSURE FORECAST TO RIPPLE ALONG THE
FRONT...AND ISENTROPIC UPGLIDE ATOP IT...WILL PROMOTE A LIKELY
PROBABILITY OF SHOWERS AND STORMS THROUGH MON...PARTICULARLY OVER
THE EASTERN PIEDMONT AND COASTAL PLAIN. NORTHEASTERLY FLOW AND
ASSOCIATED MOSTLY CLOUDY CONDITIONS...AND CHANCE OF SHOWERS...WILL
PREVAIL OVER THE SOUTHERN AND WESTERN PIEDMONT. COOLER WITH HIGHS
MOSTLY IN THE 70S...AND LOWS 65 TO 70.
TUE-THU: SFC WAVES DEPART WITH LESSENING INFLUENCE OF THE
NORTHEASTERLY FLOW...WITH ASSOCIATED DECREASING CLOUDINESS...AND
MODERATION INTO THE UPPER 70S TO MIDDLE 80S. SHOWER AND STORM
CHANCES...JUST SLIGHT TO LOW CHANCE ONES...SHOULD BE CONFINED TO
EASTERN AREAS TUE...WITH TYPICAL POP DISTRIBUTION INVOF THE SEA
BREEZE AND MOUNTAINS AS CENTRAL NC REMAINS BETWEEN THE DEPARTING SFC
WAVES AND THE NEXT FRONT FORECAST TO ARRIVE LATE NEXT WEEK.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 145 AM FRIDAY...
EARLY CONVECTION HAD DWINDLED IN THE PAST COUPLE OF HOURS..LEAVING
JUST SOME AREAS OF VERY LIGHT THAT WILL ALSO COME TO AN END.
CONDITIONS HAVE IMPROVED TO VFR ACROSS ALL OF CENTRAL NC...BUT
EXPECT SOME STRATUS TO REDEVELOP BY 09-10Z...ESPECIALLY IN AREAS
THAT RECEIVED MORE SIGNIFICANT RAINFALL LAST EVENING. BASED ON
THIS...CONFIDENCE IN SUB-VFR...LIKELY IFR OR LIFR...CEILINGS IS
GREATEST AT KRDU AND KRWI.
STRATUS WILL DISPERSE AND VFR CONDITIONS ARE EXPECTED AGAIN BY MID-
MORNING. SHOWERS AND STORMS ARE POSSIBLE AGAIN THIS
AFTERNOON/EVENING...MORE LIKELY AT KFAY AND KGSO/KINT...THOUGH THE
OVERALL COVERAGE IS EXPECTED TO BE LESS THAN IN THE PAST COUPLE OF
DAYS.
OUTLOOK...A COLD FRONT WILL APPROACH THE REGION LATE SATURDAY INTO
SUNDAY...LEADING TO INCREASED CHANCES OF SHOWERS AND THUNDERSTORMS.
THE BEST CHANCES OF CONVECTION WILL SHIFT TOWARDS THE SOUTH AND EAST
BY EARLY NEXT WEEK AS THE FRONT STALLS NEAR THE COAST. LOW
CLOUDS/FOG WILL BE POSSIBLE EACH MORNING...WITH POSSIBLY AN
EXTENDED PERIOD OF SUB VFR CONDITIONS EARLY NEXT WEEK AS HIGH
PRESSURE EXTENDS DOWN INTO THE REGION AND MOIST NORTHEASTERLY FLOW
PREVAILS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...BLS
SHORT TERM...MWS
LONG TERM...MWS
AVIATION...KRD/BLS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
323 AM EDT FRI SEP 5 2014
.SYNOPSIS...HIGH PRESSURE ALOFT WILL EXTEND ACROSS CENTRAL NC
THROUGH SATURDAY. A COLD FRONT WILL CROSS THE AREA SATURDAY
NIGHT AND STALL TO OUR SOUTH ON SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 315 AM FRIDAY...
THE SUB-TROPICAL RIDGE HOLDS ON ACROSS THE SOUTHEAST US FOR ANOTHER
DAY...AS THE BERMUDA HIGH BUILDS WESTWARD ACROSS THE REGION. THE
WEAK FRONTAL ZONE NEAR THE NC/VA BORDER ON THURSDAY HAS ESSENTIALLY
WASHED OUT...LEAVING MAINLY THE SEABREEZE AND TERRAIN INDUCED
DIFFERENTIAL HEATING AS THE PRIMARY TRIGGERS FOR CONVECTION TODAY.
WHILE NOT A PROMINENT ON RADAR AS WAS THE CASE YESTERDAY...LINGERING
OUTFLOW BOUNDARIES MAY ALSO TRIGGER SOME CONVECTION. THE HRRR SHOWS
SOME LATE MORNING SHOWERS OVER THE NORTHWEST PIEDMONT...WHICH SEEMS
SOMEWHAT REASONABLE GIVEN THAT IT WAS ONE OF THE LAST PLACES TO HAVE
SHOWERS THIS MORNING. MODERATE INSTABILITY OF 1000-2000 J/KG MLCAPE
SHOULD DEVELOP THIS AFTERNOON...BUT WITH VERY WEAK
SHEAR...CONVECTION IS NOT EXPECTED TO BE PARTICULARLY INTENSE.
WILL MOSTLY MAINTAIN THE PREVIOUS FORECAST POPS OF CHANCES IN THE
NORTHWEST AND SOUTHEAST...WITH A SLIGHT CHANCE OVER THE NORTHWEST
PIEDMONT AREA THIS MORNING GIVEN THE REASONING ABOVE. HIGHS AROUND
90 DEGREES.
&&
.SHORT TERM /SATURDAY AND SATURDAY NIGHT/...
AS OF 320 AM FRIDAY...
SAT AND SAT NIGHT: ONE MORE DAY OF HEAT...IN ADVANCE OF A COLD FRONT
FORECAST TO SETTLE SOUTHEASTWARD TO A POSITION FROM EASTERN NEW
ENGLAND TO THE CENTRAL AND SOUTHERN APPALACHIANS BY SAT EVENING. A
PRE-FRONTAL TROUGH AND THE SEA-BREEZE WILL FOCUS INITIALLY DIURNAL
HEATING-DRIVEN AFTERNOON AND EVENING CONVECTION OVER THE
NORTHWESTERN AND SOUTHERN PORTIONS OF THE RAH CWFA...WITH THE LATTER
POSSIBLY ENHANCED BY THE SLOW NORTHWARD DRIFT OF AN AREA OF
DISTURBED WEATHER FORECAST TO DRIFT NORTH FROM THE EAST COAST OF FL
TO EASTERN GA AND SC. SHOWERS AND STORMS WILL LIKELY PERSIST
THROUGHOUT THE NIGHT...PARTICULARLY NORTH OF THE SANDHILLS AND
SOUTHERN COASTAL PLAIN...AS THE AFOREMENTIONED COLD FRONT OVERTAKES
THE PRE-FRONTAL TROUGH OVER NORTHERN AND CENTRAL NC OVERNIGHT. LOWS
IN THE MIDDLE TO UPPER 60S IN DEVELOPING POST-FRONTAL CAA OVER THE
NORTHERN PIEDMONT...TO LOWER 70S OVER THE WARM SECTOR IN THE
SANDHILLS AND SOUTHERN COASTAL PLAIN.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
AS OF 325 PM THURSDAY...
SATURDAY THROUGH SUNDAY: THE SUB-TROPICAL MID LEVEL RIDGE IS
EXPECTED TO BE SUPPRESSED SOUTH/EASTWARD THIS WEEKEND AS A PAIR OF
S/W DISTURBANCE TRACKING NEAR THE US./CANADIAN BORDER HELP A
MID/UPPER LEVEL TROUGH PUSH EASTWARD ACROSS THE COUNTRY AND AMPLIFY
THE APPROACHING L/W TROUGH. THIS WILL SEND AN ASSOCIATED PRE-FRONTAL
TROUGH AND EVENTUALLY COLD FRONT INTO CENTRAL NC VERY LATE SATURDAY
INTO SUNDAY. WITH A WARM MOIST AIRMASS CHARACTERIZED BY PW`S OF
AROUND 2 INCHES IN ADVANCE OF THIS SYSTEM COUPLED WITH IMPROVING
UPPER DIVERGENCE EXPECT WE SHOULD HAVE A GOOD CHANCE FOR SHOWERS AND
STORMS DURING THIS TIME FRAME. THE BEST CHANCE FOR SATURDAY THOUGH
LOOKS TO BE LATE IN THE DAY... AND BEST CHANCES ACROSS THE NORTHWEST
PIEDMONT AND POSSIBLY ALONG THE SEABREEZE ACROSS OUR SOUTHEASTERN
COUNTIES... THEN TRANSLATING SOUTH AND EASTWARD SATURDAY NIGHT INTO
SUNDAY MORNING. A 1022-1025 MB SURFACE HIGH IS EXPECTED TO BUILD
SOUTHWARD ON SUNDAY INTO SUNDAY NIGHT FROM THE NORTH. THE BEST
CHANCE FOR SHOWERS AND STORMS BY SUNDAY AFTERNOON IS EXPECTED ACROSS
THE SOUTHERN HALF OF THE AREA. WRT A SEVERE THREAT.. SURFACE BASED
CAPE VALUES ON SATURDAY ARE EXPECTED TO BE AROUND 1000-1500 J/KG...
WITH AFTERNOON SBCAPE VALUES BEST ACROSS THE FAR SOUTH ON SUNDAY OF
AROUND 1000-2000 J/KG (AS THE FRONT LOOKS TO BE PUSHING SOUTHWARD
THROUGH THE SOUTHERN HALF OF THE AREA ON SUNDAY AFTERNOON).
HOWEVER... DEEP LAYER SHEAR CONTINUES TO LOOK MARGINAL... GENERALLY
20 KTS OR LESS IN THE WARM SECTOR. THUS... THINK ANY SEVERE THREAT
WILL REMAIN QUITE ISOLATED THIS WEEKEND. HOWEVER... GIVEN THE RATHER
LIGHT STEERING FLOW AND PW`S OF AROUND 2" WE COULD SEE SOME LOCALLY
HEAVY RAIN. PRECIP WILL LIKELY CONTINUE TO LINGER ACROSS SOME IF NOT
MOST OF THE AREA ON SUNDAY NIGHT WITH A MOIST EASTERLY LOW LEVEL
FLOW... TO EAST-SOUTHEAST TO SOUTHEAST AT H85 ATOP THE COOL DOME.
HIGH TEMPS ON SATURDAY IN ADVANCE OF THE COLD FRONT ARE EXPECTED TO
GENERALLY BE AROUND 90/LOWER 90S. SUNDAY... HIGHS WILL BE TRICKY AND
DEPEND ON HOW QUICKLY THE COOLER DRY AIR FILTERS INTO THE AREA AND
HOW MUCH PRECIP WE WILL HAVE BEHIND THE FRONT. FOR NOW WILL GO WITH
HIGH TEMPS AROUND 80 NW TO THE MID TO UPPER 80S FAR SOUTH. LOWS
TEMPS SUNDAY MORNING ARE EXPECTED TO BE IN THE UPPER 60S TO LOWER
70S.. LOWS MONDAY MORNING... WITH POSSIBLY SOME LINGERING SHOWERS...
ARE EXPECTED TO BE IN THE MID 60S NORTH TO MID TO UPPER 60S SOUTH.
MONDAY THROUGH THURSDAY: THE SURFACE FRONT IS EXPECTED TO STALL AS
IT MOVES OFFSHORE AND ENCOUNTERS THE GULF STREAM/OR ALONG THE
COAST... WITH THE POTENTIAL FOR AN AREA OF LOW PRESSURE OR TWO TO
LIFT NORTHWARD ALONG THE FRONT MONDAY INTO TUESDAY. THIS WILL LEAD
TO CONTINUED LINGERING CHANCE OF SHOWERS/RAIN ACROSS THE AREA...
BEST CHANCE EAST. WITH A 1025 MB SURFACE HIGH CONTINUING TO EXTEND
INTO OUR AREA FROM THE NORTHEAST WE SHOULD SEE A COLD AIR DAMMING
AIR MASS ACROSS PORTIONS... IF NOT ALL... OF THE CWA ON MONDAY INTO
TUESDAY. HOWEVER.... THE STRENGTH AND OVERALL EVOLUTION OF THE CAD
WILL HELP DRY THE TEMPS ON MONDAY AND TUESDAY. FOR NOW WILL CONTINUE
TO TREND TEMPS TOWARDS THE COOLER SIDE FOR HIGHS. MID 70S NW TO
AROUND 80 SE FOR MONDAY (POSSIBLY TOO WARM)... WITH UPPER 70S TO
LOWER 80S ON TUESDAY AS SOME DRIER AIR ALOFT MAY BEGIN TO WORK INTO
THE AREA BY THEN.
A SLOW MODERATION WILL CONTINUE ON WEDNESDAY AND THURSDAY... AS ANY
SURFACE LOWS LIFT OFF TO THE NORTHEAST... ALONG WITH BRIEF S/W
RIDING BUILDING ACROSS THE AREA. MEDIUM RANGE MODELS DIFFER ON THE
TIMING OF THE NEXT SYSTEM AND PRECIP CHANCES BY THE END OF THE
PERIOD... THUS... WILL LIMIT POPS TO SLIGHT CHANCE BY WEDNESDAY AND
THURSDAY. HIGHS LOWER TO MID 80S... LOWS MID TO UPPER 60S AT LEAST.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 145 AM FRIDAY...
EARLY CONVECTION HAD DWINDLED IN THE PAST COUPLE OF HOURS..LEAVING
JUST SOME AREAS OF VERY LIGHT THAT WILL ALSO COME TO AN END.
CONDITIONS HAVE IMPROVED TO VFR ACROSS ALL OF CENTRAL NC...BUT
EXPECT SOME STRATUS TO REDEVELOP BY 09-10Z...ESPECIALLY IN AREAS
THAT RECEIVED MORE SIGNIFICANT RAINFALL LAST EVENING. BASED ON
THIS...CONFIDENCE IN SUB-VFR...LIKELY IFR OR LIFR...CEILINGS IS
GREATEST AT KRDU AND KRWI.
STRATUS WILL DISPERSE AND VFR CONDITIONS ARE EXPECTED AGAIN BY MID-
MORNING. SHOWERS AND STORMS ARE POSSIBLE AGAIN THIS
AFTERNOON/EVENING...MORE LIKELY AT KFAY AND KGSO/KINT...THOUGH THE
OVERALL COVERAGE IS EXPECTED TO BE LESS THAN IN THE PAST COUPLE OF
DAYS.
OUTLOOK...A COLD FRONT WILL APPROACH THE REGION LATE SATURDAY INTO
SUNDAY...LEADING TO INCREASED CHANCES OF SHOWERS AND THUNDERSTORMS.
THE BEST CHANCES OF CONVECTION WILL SHIFT TOWARDS THE SOUTH AND EAST
BY EARLY NEXT WEEK AS THE FRONT STALLS NEAR THE COAST. LOW
CLOUDS/FOG WILL BE POSSIBLE EACH MORNING...WITH POSSIBLY AN
EXTENDED PERIOD OF SUB VFR CONDITIONS EARLY NEXT WEEK AS HIGH
PRESSURE EXTENDS DOWN INTO THE REGION AND MOIST NORTHEASTERLY FLOW
PREVAILS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...BLS
SHORT TERM...MWS
LONG TERM...BSD
AVIATION...KRD/BLS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
315 AM EDT FRI SEP 5 2014
.SYNOPSIS...HIGH PRESSURE ALOFT WILL EXTEND ACROSS CENTRAL NC
THROUGH SATURDAY. A COLD FRONT WILL CROSS THE AREA SATURDAY
NIGHT AND STALL TO OUR SOUTH ON SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 315 AM FRIDAY...
THE SUB-TROPICAL RIDGE HOLDS ON ACROSS THE SOUTHEAST US FOR ANOTHER
DAY...AS THE BERMUDA HIGH BUILDS WESTWARD ACROSS THE REGION. THE
WEAK FRONTAL ZONE NEAR THE NC/VA BORDER ON THURSDAY HAS ESSENTIALLY
WASHED OUT...LEAVING MAINLY THE SEABREEZE AND TERRAIN INDUCED
DIFFERENTIAL HEATING AS THE PRIMARY TRIGGERS FOR CONVECTION TODAY.
WHILE NOT A PROMINENT ON RADAR AS WAS THE CASE YESTERDAY...LINGERING
OUTFLOW BOUNDARIES MAY ALSO TRIGGER SOME CONVECTION. THE HRRR SHOWS
SOME LATE MORNING SHOWERS OVER THE NORTHWEST PIEDMONT...WHICH SEEMS
SOMEWHAT REASONABLE GIVEN THAT IT WAS ONE OF THE LAST PLACES TO HAVE
SHOWERS THIS MORNING. MODERATE INSTABILITY OF 1000-2000 J/KG MLCAPE
SHOULD DEVELOP THIS AFTERNOON...BUT WITH VERY WEAK
SHEAR...CONVECTION IS NOT EXPECTED TO BE PARTICULARLY INTENSE.
WILL MOSTLY MAINTAIN THE PREVIOUS FORECAST POPS OF CHANCES IN THE
NORTHWEST AND SOUTHEAST...WITH A SLIGHT CHANCE OVER THE NORTHWEST
PIEDMONT AREA THIS MORNING GIVEN THE REASONING ABOVE. HIGHS AROUND
90 DEGREES.
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 325 PM THURSDAY...
MID-LEVEL SHEAR AXIS WILL BE EDGES NWD FRIDAY AS BERMUDA HIGH
TEMPORARILY RE-EXERTS ITSELF ACROSS THE CAROLINAS. MODEST HEIGHT
RISES AND ASSOCIATED MID LEVEL SUBSIDENCE INVERSION SHOULD HELP TO
LIMIT CONVECTION INITIATION. THUS CONVECTION WILL BE MORE
SPARSE/ISOLATED COMPARED TOT HE PAST FEW DAYS. AREAS OF EARLY
MORNING LOW CLOUDS/FOG WILL GIVE WAY TO PARTLY SUNNY-MOSTLY SUNNY
SKIES BY MID DAY. THIS HEATING SHOULD BOOST AFTERNOON TEMPS NEAR 90-
LOWER 90S.
CONVECTION WILL DIMINISH SHORTLY AFTER SUNSET. SIMILAR TO THE PAST
FEW NIGHTS....EXPECT AREAS OF LOW CLOUDS AND/OR FOG TO DEVELOP AFTER
MIDNIGHT. MIN TEMPS 68-73.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
AS OF 325 PM THURSDAY...
SATURDAY THROUGH SUNDAY: THE SUB-TROPICAL MID LEVEL RIDGE IS
EXPECTED TO BE SUPPRESSED SOUTH/EASTWARD THIS WEEKEND AS A PAIR OF
S/W DISTURBANCE TRACKING NEAR THE US./CANADIAN BORDER HELP A
MID/UPPER LEVEL TROUGH PUSH EASTWARD ACROSS THE COUNTRY AND AMPLIFY
THE APPROACHING L/W TROUGH. THIS WILL SEND AN ASSOCIATED PRE-FRONTAL
TROUGH AND EVENTUALLY COLD FRONT INTO CENTRAL NC VERY LATE SATURDAY
INTO SUNDAY. WITH A WARM MOIST AIRMASS CHARACTERIZED BY PW`S OF
AROUND 2 INCHES IN ADVANCE OF THIS SYSTEM COUPLED WITH IMPROVING
UPPER DIVERGENCE EXPECT WE SHOULD HAVE A GOOD CHANCE FOR SHOWERS AND
STORMS DURING THIS TIME FRAME. THE BEST CHANCE FOR SATURDAY THOUGH
LOOKS TO BE LATE IN THE DAY... AND BEST CHANCES ACROSS THE NORTHWEST
PIEDMONT AND POSSIBLY ALONG THE SEABREEZE ACROSS OUR SOUTHEASTERN
COUNTIES... THEN TRANSLATING SOUTH AND EASTWARD SATURDAY NIGHT INTO
SUNDAY MORNING. A 1022-1025 MB SURFACE HIGH IS EXPECTED TO BUILD
SOUTHWARD ON SUNDAY INTO SUNDAY NIGHT FROM THE NORTH. THE BEST
CHANCE FOR SHOWERS AND STORMS BY SUNDAY AFTERNOON IS EXPECTED ACROSS
THE SOUTHERN HALF OF THE AREA. WRT A SEVERE THREAT.. SURFACE BASED
CAPE VALUES ON SATURDAY ARE EXPECTED TO BE AROUND 1000-1500 J/KG...
WITH AFTERNOON SBCAPE VALUES BEST ACROSS THE FAR SOUTH ON SUNDAY OF
AROUND 1000-2000 J/KG (AS THE FRONT LOOKS TO BE PUSHING SOUTHWARD
THROUGH THE SOUTHERN HALF OF THE AREA ON SUNDAY AFTERNOON).
HOWEVER... DEEP LAYER SHEAR CONTINUES TO LOOK MARGINAL... GENERALLY
20 KTS OR LESS IN THE WARM SECTOR. THUS... THINK ANY SEVERE THREAT
WILL REMAIN QUITE ISOLATED THIS WEEKEND. HOWEVER... GIVEN THE RATHER
LIGHT STEERING FLOW AND PW`S OF AROUND 2" WE COULD SEE SOME LOCALLY
HEAVY RAIN. PRECIP WILL LIKELY CONTINUE TO LINGER ACROSS SOME IF NOT
MOST OF THE AREA ON SUNDAY NIGHT WITH A MOIST EASTERLY LOW LEVEL
FLOW... TO EAST-SOUTHEAST TO SOUTHEAST AT H85 ATOP THE COOL DOME.
HIGH TEMPS ON SATURDAY IN ADVANCE OF THE COLD FRONT ARE EXPECTED TO
GENERALLY BE AROUND 90/LOWER 90S. SUNDAY... HIGHS WILL BE TRICKY AND
DEPEND ON HOW QUICKLY THE COOLER DRY AIR FILTERS INTO THE AREA AND
HOW MUCH PRECIP WE WILL HAVE BEHIND THE FRONT. FOR NOW WILL GO WITH
HIGH TEMPS AROUND 80 NW TO THE MID TO UPPER 80S FAR SOUTH. LOWS
TEMPS SUNDAY MORNING ARE EXPECTED TO BE IN THE UPPER 60S TO LOWER
70S.. LOWS MONDAY MORNING... WITH POSSIBLY SOME LINGERING SHOWERS...
ARE EXPECTED TO BE IN THE MID 60S NORTH TO MID TO UPPER 60S SOUTH.
MONDAY THROUGH THURSDAY: THE SURFACE FRONT IS EXPECTED TO STALL AS
IT MOVES OFFSHORE AND ENCOUNTERS THE GULF STREAM/OR ALONG THE
COAST... WITH THE POTENTIAL FOR AN AREA OF LOW PRESSURE OR TWO TO
LIFT NORTHWARD ALONG THE FRONT MONDAY INTO TUESDAY. THIS WILL LEAD
TO CONTINUED LINGERING CHANCE OF SHOWERS/RAIN ACROSS THE AREA...
BEST CHANCE EAST. WITH A 1025 MB SURFACE HIGH CONTINUING TO EXTEND
INTO OUR AREA FROM THE NORTHEAST WE SHOULD SEE A COLD AIR DAMMING
AIR MASS ACROSS PORTIONS... IF NOT ALL... OF THE CWA ON MONDAY INTO
TUESDAY. HOWEVER.... THE STRENGTH AND OVERALL EVOLUTION OF THE CAD
WILL HELP DRY THE TEMPS ON MONDAY AND TUESDAY. FOR NOW WILL CONTINUE
TO TREND TEMPS TOWARDS THE COOLER SIDE FOR HIGHS. MID 70S NW TO
AROUND 80 SE FOR MONDAY (POSSIBLY TOO WARM)... WITH UPPER 70S TO
LOWER 80S ON TUESDAY AS SOME DRIER AIR ALOFT MAY BEGIN TO WORK INTO
THE AREA BY THEN.
A SLOW MODERATION WILL CONTINUE ON WEDNESDAY AND THURSDAY... AS ANY
SURFACE LOWS LIFT OFF TO THE NORTHEAST... ALONG WITH BRIEF S/W
RIDING BUILDING ACROSS THE AREA. MEDIUM RANGE MODELS DIFFER ON THE
TIMING OF THE NEXT SYSTEM AND PRECIP CHANCES BY THE END OF THE
PERIOD... THUS... WILL LIMIT POPS TO SLIGHT CHANCE BY WEDNESDAY AND
THURSDAY. HIGHS LOWER TO MID 80S... LOWS MID TO UPPER 60S AT LEAST.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 145 AM FRIDAY...
EARLY CONVECTION HAD DWINDLED IN THE PAST COUPLE OF HOURS..LEAVING
JUST SOME AREAS OF VERY LIGHT THAT WILL ALSO COME TO AN END.
CONDITIONS HAVE IMPROVED TO VFR ACROSS ALL OF CENTRAL NC...BUT
EXPECT SOME STRATUS TO REDEVELOP BY 09-10Z...ESPECIALLY IN AREAS
THAT RECEIVED MORE SIGNIFICANT RAINFALL LAST EVENING. BASED ON
THIS...CONFIDENCE IN SUB-VFR...LIKELY IFR OR LIFR...CEILINGS IS
GREATEST AT KRDU AND KRWI.
STRATUS WILL DISPERSE AND VFR CONDITIONS ARE EXPECTED AGAIN BY MID-
MORNING. SHOWERS AND STORMS ARE POSSIBLE AGAIN THIS
AFTERNOON/EVENING...MORE LIKELY AT KFAY AND KGSO/KINT...THOUGH THE
OVERALL COVERAGE IS EXPECTED TO BE LESS THAN IN THE PAST COUPLE OF
DAYS.
OUTLOOK...A COLD FRONT WILL APPROACH THE REGION LATE SATURDAY INTO
SUNDAY...LEADING TO INCREASED CHANCES OF SHOWERS AND THUNDERSTORMS.
THE BEST CHANCES OF CONVECTION WILL SHIFT TOWARDS THE SOUTH AND EAST
BY EARLY NEXT WEEK AS THE FRONT STALLS NEAR THE COAST. LOW
CLOUDS/FOG WILL BE POSSIBLE EACH MORNING...WITH POSSIBLY AN
EXTENDED PERIOD OF SUB VFR CONDITIONS EARLY NEXT WEEK AS HIGH
PRESSURE EXTENDS DOWN INTO THE REGION AND MOIST NORTHEASTERLY FLOW
PREVAILS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...BLS
SHORT TERM...WSS
LONG TERM...BSD
AVIATION...KRD/BLS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
146 AM EDT FRI SEP 5 2014
.SYNOPSIS...
SUMMERTIME WEATHER WILL CONTINUE INTO THE WEEKEND. AN APPROACHING
COLD FRONT WILL BRING AN INCREASED RISK OF THUNDERSTORMS LATE IN THE
WEEKEND AND EARLY NEXT WEEK. A STRONGER COLD FRONT MAY APPROACH THE
AREA BY THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS OF 1045 PM THURSDAY...PCPN TREND FROM THE PREVIOUS UPDATE
STILL HOLDS. HAVE TEMPORARILY ENDED PCPN OVER LAND AREAS ACROSS
THE ILM CWA. BUT WILL CONTINUE THE INCREASING DEVELOPMENT OF
NOCTURNAL SHRA/TSRA ACROSS THE ADJACENT ATL WATERS DURING THE PRE-
DAWN FRI HRS VIA LATEST HRRR MODEL OUTPUT. THE EVENTUAL ONSHORE
MOVEMENT OF THIS PCPN WILL OCCUR TOWARD DAYBREAK FRI...AND THUS
WILL MAINTAIN ATLEAST A 20 POP FOR THE COASTAL COUNTIES AND EXTEND
FURTHER INLAND AFTER SUNRISE FRI. NO TWEAKS TO OVERNITE TEMPS/DEWPTS
AT THIS TIME.
PREVIOUS DISCUSSION.............................................
AS OF 715 PM THURSDAY...LATEST KLTX 88D AND SURROUNDING 88DS
INDICATE THE DIURNALLY DRIVEN CONVECTION HAS ENDED ACROSS THE ILM
CWA. AS A RESULT...HAVE REMOVED POPS FOR THE REMAINDER OF THIS
EVENING AND INTO THE PRE-DAWN FRI HRS. IN ADDITION HAVE DECREASED
CLOUD COVERAGE GIVEN LATEST SAT IMAGERY...AND WITH CONVECTIVE
DEBRIS CLOUDS REMAINING WELL UPSTREAM. HOWEVER...HAVE RAMPED UP THE
NOCTURNAL SHRA/TSRA POP ALONG THE COASTAL COUNTIES FROM PCPN MOVING
ONSHORE FROM OFF THE ATL OCEAN TO ATLEAST 20...AND POSSIBLY UP TO 30
LEADING UP TO FRI SUNRISE AND IMMEDIATELY THERE-AFTER. VARIOUS MODEL
TIME HEIGHT DISPLAYS ACROSS COASTAL NC-SC INDICATE A MUCH DEEPER
ONSHORE FLOW...IE. SE-SSW FLOW UP TO 5H...ACROSS COASTAL NC-SC...AND
ALSO ALONG WITH PLENTY OF LOW-LEVEL MOISTURE AFTER MIDNIGHT
FRI...EXTENDING FROM THE SFC UP THRU 8H. ONSHORE FLOW HAVING CROSSED
SSTS AROUND 80 DEGREES...WILL KEEP TONIGHTS LOWS IN THE MID AND
UPPER 70S AT THE COAST. LOWER 70S LIKELY FAR WEST PORTIONS...MAINLY
ALONG AND WEST OF THE I-95 CORRIDOR.
PREVIOUS DISCUSSION..................................
AS OF 130 PM THURSDAY...FORECAST FOR THE AFTERNOON AND OVERNIGHT
HOURS REMAINS RELATIVELY UNCHANGED. ALL WE HAVE SEEN SO FAR IS
VERY SHALLOW TROPICAL SHOWERS AND THE CUMULUS FIELD LOOKS LIKE
THIS CWA WIDE SO THE CHANCE OF DEEP CONVECTION IS DIMINISHING.
STILL CANT RULE OUT SOME DEEPER ACTIVITY ACROSS NORTHWESTERN AREAS
AND WILL ADJUST POPS ACCORDINGLY IF NECESSARY. WILL MAINTAIN THE
LOW CHANCE POPS FOR THE AFTERNOON HOURS AND FOR THE ACTIVITY
EXPECTED TO DEVELOP ACROSS THE ATLANTIC OVERNIGHT. OVERNIGHT LOWS
REMAIN STEAMY AND OPTED FOR THE WARMER GUIDANCE WHICH HAS BEEN A
GOOD PLAY RECENTLY.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
AS OF 300 PM THURSDAY...HAVE FAVORED THE SLOWER GFS SOLUTION FOR
THIS PERIOD OVER THE MORE PROGRESSIVE NAM. HIGH PRESSURE CONTINUES
ACROSS THE SOUTHEAST AS THE DOMINATE WEATHER MAKER...WEAK SURFACE
FLOW WILL ALLOW SEA BREEZE TO PUSH INLAND AND THIS WILL SERVE AS
THE MAIN TRIGGER ELEMENT FOR ANY SHOWERS OR STORMS THAT DEVELOP
THROUGHOUT THE AFTERNOON. HAVE FAVORED THE LOWER CHANCE POPS OF
THE GFS AS NAM RAMPS UP POPS I THINK TOO QUICKLY BY LATE DAY IN THE
ABSENCE OF ANY UPPER LEVEL DISTURBANCE THAT REMAINS WELL TO THE
WEST OF THE CWA BY FRIDAY LATE AFTERNOON. APPROACHING FRONTAL
BOUNDARY WILL REMAIN WELL TO OUR WEST AND NORTHWEST FRIDAY. WITH
LESS CLOUD COVER ON THE GFS THAN NAM FAVORED THE HIGHER GFS TEMPS
OF UPPER 80S TO AROUND 90 INLAND WITH H8 TEMPS AROUND 18C WITH A
WEAK LESS THAN 10 KT SOUTHERLY H8 FLOW INCREASING MOISTURE INTO
THE REGION. ON SATURDAY I START TO RAMP UP THE POPS BY THE END OF
THE PERIOD AS COMBINATION OF INCREASED SOUTHERLY H8 SPEED
CONVERGENCE INTERACTS WITH SEA BREEZE FRONT TO IGNITE MORE
SCATTERED SHOWERS AND STORMS ESPECIALLY LATER IN THE AFTERNOON.
WEAK H5 DISTURBANCE MOVES INTO THE WESTERN PORTION OF THE STATE
AND SHOULD ENHANCE THE PIEDMONT TROUGH CONVECTION DURING SATURDAY
EVENING SO WILL UP THE POPS HERE LATE IN THE PERIOD. WITH A JUICY
ATMOSPHERE ANY SHOWERS OR STORMS WILL HAVE THE POTENTIAL TO
PRODUCE SOME LOCALLY HEAVY RAINS ESPECIALLY INLAND AS THE STEERING
WINDS WILL BE LIGHTER COMPARED TO NEAR THE COAST WHERE THE LOW
LEVEL JET SHOULD HAVE A 190 DIRECTION AT AROUND 15 KNOTS WHICH
SHOULD HELP IN KEEPING ANY PROLONG PERIOD OF RAIN OVER ANY AREA.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 300 PM THURSDAY...THE SUBTROPICAL RIDGE WILL REMAIN TO OUR
SOUTH NEXT WEEK WITH THE SOUTHERN EDGE OF THE MID-LATITUDE
WESTERLIES BRUSHING THE CAROLINAS. MODELS SHOW THE BEST POTENTIAL
FOR DEEP MOISTURE AND CYCLONIC CURVATURE TO THE 500 MB FLOW WILL
BE SUNDAY/MONDAY...COINCIDENT WITH THE ARRIVAL OF A COLD FRONT
PUSHED SOUTHWARD INTO THE CAROLINAS BY SURFACE HIGH PRESSURE OVER
THE UPPER MIDWEST. AS WEAK LOW PRESSURE DEVELOPS ALONG THE STALLED
FRONT OVER SOUTHERN SOUTH CAROLINA/EASTERN GEORGIA MONDAY...MOIST
SOUTHEAST WINDS WILL ADVECT PLENTY OF ATLANTIC MOISTURE ONSHORE
ACROSS THE AREA. THIS COULD LEAD TO FAIRLY WIDESPREAD SHOWERS AND
T-STORMS. I HAVE INCREASED FORECAST POPS TO 50-70 PERCENT SUNDAY
AND MONDAY.
ONE INTERESTING FEATURE THAT WILL HAVE TO BE WATCHED CLOSELY IS
LOCATED OFF THE FLORIDA EAST COAST THIS AFTERNOON. MODELS SHOW SOME
OF THE DEEP TROPICAL MOISTURE TRAILING BEHIND THIS CYCLONIC SWIRL
COULD BE INGESTED INTO THE SUNDAY/MONDAY WEATHER SYSTEM. WHILE THIS
NOT GOING TO BE A TROPICAL SYSTEM PER SE...ADVECTING TROPICAL
MOISTURE ACROSS A SYNOPTIC COLD FRONT CAN LEAD TO SIGNIFICANT AND
PERHAPS EXCESSIVE RAINFALL.
THE WEAK SURFACE LOW SHOULD LIFT OUT TO THE NORTHEAST TUESDAY WITH
RAINFALL CHANCES DIMINISHING THROUGH MID-WEEK. THE AIRMASS WILL
REMAIN TROPICAL AND MAINLY DIURNAL 20-30 POPS WILL REMAIN IN THE
FORECAST.
HIGH TEMPERATURES WILL REMAIN BELOW CLIMATOLOGICAL NORMS MONDAY AND
TUESDAY DUE TO THE CLOUDS AND PRECIP ANTICIPATED WITH THE FRONT
STALLING NEAR THE AREA. ONCE THIS FEATURE IS GONE TUESDAY HIGH
TEMPERATURES SHOULD REMAIN TO NEAR OR EVEN SLIGHTLY ABOVE NORMALS
FOR THE REST OF THE WEEK.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 06Z...POTENTIAL FOR MVFR/IFR DUE TO FOG OVERNIGHT INTO THE
EARLY MORNING HOURS. OTHERWISE EXPECT VFR WITH A CHANCE OF AFTERNOON
SHRA/TSRA ON THURSDAY.
LIGHT WINDS AND VFR PREVAILS THIS EVENING. THERE IS THE POTENTIAL
FOR MVFR/POSSIBLE IFR DUE TO AREAS OF FOG/LOW CIGS AT THE INLAND
SITES AROUND DAYBREAK. DO NOT ANTICIPATE ANY OF THIS TO DEVELOP
ALONG THE COAST...BUT COULD SEE SOME ISOLATED SHOWER ACTIVITY MOVE
ASHORE. AFTER SUNRISE...VFR WILL PREVAIL WITH SOUTH-SOUTHEAST WINDS
AROUND 5 TO 10 KT...SLIGHTLY HIGHER ALONG THE COAST...WITH A
CHANCE OF SHRA/TSRA. INTO THE EVENING HOURS...WINDS WILL DECREASE
AND ANY SHRA/TSRA ACTIVITY WILL TAPER OFF.
EXTENDED OUTLOOK...PATCHY MVFR/IFR FOG OR STRATUS MAY DEVELOP EACH
MORNING. A COLD FRONT WILL DROP INTO THE REGION SUNDAY AND MONDAY...
WITH A HIGHER RISK FOR SHOWERS AND STORMS BOTH DAYS. THE FRONT
STALLS WITH A CONTINUED CHANCE FOR SHOWERS TUESDAY.
&&
.MARINE...
NEAR TERM/THROUGH TONIGHT/...
AS OF 1100 PM THURSDAY...NEARLY A PCPN FREE COASTAL AND
ADJACENT OFFSHORE WATERS AT THE MOMENT...VIA LATEST KLTX 88D
AND SURROUNDING RADARS. STILL BANKING ON THE LATEST HRRR WHICH
INDICATES PCPN RE-FIRING DURING THE PRE-DAWN FRI HRS. NO POP
CHANGES NEEDED AT THIS TIME. LATEST BUOYS OBS ACROSS AND IN THE
NEIGHBORHOOD OF THE ILM COASTAL WATERS CONTINUE TO SUPPORT THE
PREVIOUS UPDATE WITH VERY LITTLE TWEAKING...IF ANY...NEEDED TO
EITHER WINDS/SEAS IN THIS UPDATE.
PREVIOUS DISCUSSION..............................................
AS OF 730 PM THURSDAY...LATEST PROGGED SFC PRESSURE PATTERN AND
RELAXED GRADIENT ACROSS THE ILM WATERS OVERNIGHT TO YIELD A SE-S
WIND AT 10 TO 15 KT...WITH THE 15 KT BEING VERY GENEROUS.
SIGNIFICANT SEAS WILL REMAIN IN A 2 TO 3 FOOT RANGE...WITH THE
DOMINANT PLAYER WITH THE SIG. SEAS BEING A LAZY 2 FOOT ESE GROUND
SWELL EXHIBITING 8 SECOND PERIODS. THE REMAINDER OF THE SIG. SEAS
PRODUCTION WILL COME FROM A 1-2 FOOT LOCALLY PRODUCED WIND WAVE AT
4-5 SECOND PERIODS. NOCTURNAL SHRA/TSRA WILL INCREASE IN COVERAGE
ACROSS THE LOCAL WATERS DURING THE MID TO LATE PRE-DAWN FRI HRS.
PREVIOUS DISCUSSION...........................................
AS OF 130 PM THURSDAY...MUCH LIKE THE PUBLIC PART OF THE
FORECAST...THE COASTAL WATERS FORECAST REMAINS STABLE. SOUTH WINDS
HOVERING AROUND TEN KNOTS WILL CONTINUE. SIGNIFICANT SEAS WILL BE
1-3 FEET WITH MOSTLY LOCAL WIND DRIVEN WAVES WITH PERIODS OF SIX
TO EIGHT SECONDS.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 PM THURSDAY...HIGH PRESSURE WILL COVER THE COASTAL
WATERS THROUGHOUT THE PERIOD. WINDS WILL GENERALLY BE LIGHT
ACROSS THE WATERS FROM THE S TO SE BUT SHOULD START TO INCREASE BY
AFTERNOON AND EVENING ON SATURDAY AS H8 WINDS DEVELOP THE LOW
LEVEL JET. SEAS WILL GENERALLY RUN AROUND A FOOT OR SO NEAR SHORE
AND 2-3 OFFSHORE. EXPECT SOME SCATTERED SHOWERS STORMS EACH DAY
WITH CONDITIONS STARTING TO DETERIORATE MORE BY THE END OF THE
PERIOD AS A COLD FRONT APPROACHES FROM THE WEST AND LOW PRESSURE
IS FORECAST TO DEVELOP ALONG THIS FRONT FOR THE LONG TERM PERIOD.
LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 300 PM THURSDAY...1022 MB HIGH PRESSURE OVER THE UPPER
MIDWEST SUNDAY WILL PUSH A COLD FRONT SOUTHWARD ACROSS THE MID-
ATLANTIC REGION. THIS FRONT SHOULD REACH THE INLAND CAROLINAS
DURING THE DAY SUNDAY BUT WILL HAVE TROUBLE PUSHING OUT ACROSS THE
COASTAL WATERS. THE LATEST SUITE OF COMPUTER MODEL DATA SHOWS THE
FRONT SHOULD REMAIN INLAND WITH SOUTH WINDS VEERING MORE
SOUTHEASTERLY MONDAY. LOW PRESSURE WILL FORM ALONG THE INLAND
PORTION OF THE FRONT ACROSS EASTERN GEORGIA/SOUTHERN SOUTH
CAROLINA MONDAY...AND AS THIS LOW PUSHES NORTHEASTWARD IT SHOULD
VEER WINDS MORE SOUTHWESTERLY TUESDAY. OUTSIDE OF THUNDERSTORMS
WIND SPEEDS SHOULD REMAIN LESS THAN 15 KNOTS THROUGH THE
PERIOD...STRONGEST SUNDAY NIGHT INTO MONDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DCH/SHK
SHORT TERM...MAC
LONG TERM...TRA
AVIATION...SGL/RJD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
547 AM EDT FRI SEP 5 2014
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO DRIFT EAST OF THE MID ATLANTIC
COAST TODAY. A COLD FRONT WILL PUSH SOUTHEAST ACROSS THE STATE ON
SATURDAY. HIGH PRESSURE OVER THE MIDWEST WILL THEN SLIDE ACROSS
PENNSYLVANIA SUNDAY INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
11-3.9 MICRON SATL IMAGERY SHOWING EXTENSIVE FOG IN THE VALLEYS OF
CENTRAL PA EARLY THIS MORNING...AS WELL AS STRATUS ACROSS EASTERN
PA. THE LOW CLOUDS AND FOG SHOULD BURN OFF BY 13Z-14Z BASED ON
CLIMATOLOGY AND LATEST HRRR OUTPUT. FOCUS THEN SHIFTS TOWARD
POTENTIAL OF SCT DIURNAL CONVECTION ACROSS SOUTHEAST PA. PWATS ARE
PROJECTED TO APPROACH 2 INCHES IN THIS AREA AND HEATING OF THIS
MOIST/UNSTABLE AIR MASS SHOULD RESULT IN MODERATE CAPES OF ARND
2000J/JG BY THIS AFTN ACROSS THE LOWER SUSQ VALLEY BASED ON
LATEST OPER MODEL AND GEFS OUTPUT. SCT PULSE-TYPE TSRA SHOULD
DEVELOP ACROSS THE SOUTHERN COUNTIES AS CONVECTIVE TEMP IS REACHED
DURING THE AFTN. WILL HAVE TO WATCH FOR LOCALLY EXCESSIVE
RAINFALL...AS ANY STORMS WILL BE SLOW-MOVERS DUE TO WEAK FLOW
ALOFT. CONVECTION-ALLOWING MDL DATA HINTS AT THIS POTENTIAL WITH
SPOT AMTS OF OVR 3 INCHES ACROSS THE LOWER SUSQ VALLEY.
GEFS 925/850 TEMPS SUPPORT HIGH TEMPS IN THE M-U80S...WITH THE
GREATEST DEPARTURES FROM AVERAGE ACROSS THE W MTNS. WHEN COMBINED
WITH HIGH HUMIDITY...APPARENT TEMPS WILL RANGE FROM THE U80S TO
L90S...PERHAPS THE WARMEST WE/LL SEE UNTIL NEXT YEAR.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
IN THE ABSENCE OF LG SCALE FORCING...DIURNALLY-DRIVEN SCT
CONVECTION ACROSS SOUTHERN PA SHOULD DIE OFF SHORTLY AFTER SUNSET.
TRANQUIL AND VERY WARM CONDS EXPECTED FOR THE REST OF THE NIGHT
OVR MOST OF CENTRAL PA...AS COLD FRONT REMAINS WEST OF THE AREA.
MDL TIMING OF COLD FRONT SUGGESTS SHRA/TSRA WILL MOVE INTO THE NW
MTNS ARND OR SHORTLY AFTER DAWN SATURDAY.
HAVE INCREASED POPS TO NR 80 PCT SATURDAY FOR PASSAGE OF COLD
FRONT BASED ON ABUNDANCE OF PRE-FRONTAL MOISTURE AND FAIRLY STRONG
FORCING AHEAD OF APPROACHING SHORTWAVE...AS IMPLIED BY MDL
500-300MB Q-VEC CONVERGENCE FIELDS. GEFS PWATS RUNNING BTWN 1-2SD
ABV NORMAL IN ADVANCE OF CDFRONT. 00Z GEFS/03Z SREF DATA ALSO
BOTH SUPPORT CATEGORICAL POPS ACROSS MOST OF CENTRAL PA. MORNING
SHOWERS ACROSS THE NW MTNS SHOULD GIVE WAY TO PM TSRA OVR THE
SOUTHERN COUNTIES...WHERE EARLY HEATING WILL RESULT IN A
MODERATELY UNSTABLE PRE-FRONTAL AIR MASS BY AFTN. HOWEVER...FAIRLY
MODEST MID LVL WINDS AND DEEP LYR SHEAR POINT TOWARD A LIMITED SVR
WX THREAT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
*COOLER/DRY WEATHER SUNDAY INTO MONDAY
*NEAR AVERAGE TEMPERATURES AND MORE UNSETTLED CONDITIONS TUE-THU
THE REGIONAL PATTERN ALOFT WILL FEATURE INCREASING TROUGHINESS
THROUGH THE MEDIUM RANGE PERIOD...WITH THE GLOBAL ENSEMBLE MEANS
SHOWING A CORE OF NEGATIVE HEIGHT ANOMALIES OVER THE UPPER MIDWEST
AND GREAT LAKES REGIONS BY THE MIDDLE TO LATER PART OF NEXT WEEK
/SEPT 11-12TH/. OVERALL...THE NAEFS/GEFS AND ECENS ALL SIGNAL A
TRANSITION TOWARD A HIGHER AMPLITUDE PATTERN PARTICULARLY ACROSS
SOUTH CENTRAL CANADA.
AN ELONGATED COLD FRONT TRAILING A RELATIVELY STRONG SFC LOW OVER
NEWFOUNDLAND/LABRADOR WILL BE PASSING SOUTH OF PA SAT NIGHT. A
MODIFIED CANADIAN HIGH BUILDING SWD INTO THE CENTRAL PLAINS WILL
EVENTUALLY SHIFT EWD THROUGH THE NORTHEAST STATES AND MOVE INTO
THE MARITIMES BY NEXT WED.
SHRA/TSRA WILL END FROM NW-SE SAT NGT WITH MUCH DRIER AIR
FILTERING IN FOR SUNDAY. DRY WX SHOULD CONTINUE INTO EARLY NEXT
WEEK BEFORE CONDS TURN MORE UNSETTLED. EASTERLY WINDS TO THE SOUTH
OF HP CELL MOVG INTO THE MARITIMES ARE SUGGESTIVE OF A COOL-AIR
WEDGE OVER THE MID-ATLC WHICH SHOULD DAYTIME HIGHS NEAR AVG.
&&
.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
OBS AND SATL IMAGERY SHOWING VALLEY FOG ACROSS NORTHWEST PA EARLY
THIS MORNING. CONTINUED RADIATIONAL COOLING UNDER MCLEAR SKIES
AND A LIGHT WIND WILL CAUSE VALLEY FOG AND A THIN STRATOCU DECK TO
BECOME MORE WIDESPREAD ACROSS CENTRAL PA WITH LOCALLY DENSE FOG
EXPECTED...ESP IN THE DEEP RIVER/STREAM VALLEYS OF THE
ALLEGHENIES. MANY LOCATIONS LIKELY TO EXPERIENCE A PERIOD OF IFR-
LIFR CONDS NEAR DAWN.
FOG SHOULD BURN OFF BY 14Z...WITH HAZE POTENTIALLY LINGERING
THROUGH MID/LATE MORNING IN THE SE. FOCUS THEN SHIFTS TOWARD
POTENTIAL FOR SCT DIURNAL CONVECTION ACROSS SOUTHEAST PA. PWATS
ARE PROJECTED TO APPROACH 2 INCHES IN THIS AREA AND HEATING OF
THIS MOIST/UNSTABLE AIR MASS SHOULD RESULT IN MODERATE CAPES OF
ARND 2000J/JG ACROSS THE LOWER SUSQ VALLEY BASED ON LATEST OPER
MODEL AND GEFS OUTPUT. SCT PULSE- TYPE TSRA SHOULD DEVELOP ACROSS
THE SOUTHERN COUNTIES BRINGING LOCAL RESTRICTIONS AS CONVECTIVE
TEMP IS REACHED DURING THE AFTN...AND ANY STORMS WILL BE SLOW-
MOVERS DUE TO WEAK FLOW ALOFT.
OUTLOOK...
SAT...AM SHRA/LOW CIGS POSS NW MTNS. PM TSRA IMPACTS POSS
ELSEWHERE.
SUN...AM FOG POSS NW MTNS.
MON...PATCHY AM VALLEY FOG POSS.
TUE...CHC SHOWERS/TSTMS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD/STEINBUGL
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
416 AM EDT FRI SEP 5 2014
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO DRIFT EAST OF THE MID ATLANTIC
SEABOARD TONIGHT BRINGING VERY WARM AND HUMID CONDITIONS FOR
FRIDAY. A COLD FRONT WILL MOVE EAST FROM THE OHIO VALLEY AND
CROSS THE STATE SATURDAY AFTERNOON AND EVENING. A REFRESHINGLY
COOLER AND MUCH DRIER AIRMASS WILL OVERSPREAD THE REGION FOR
SUNDAY AND MONDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
11-3.9 MICRON SATL IMAGERY ALREADY SHOWING THE PRESENCE OF VALLEY
FOG ACROSS NORTHWEST PA AT 06Z. CONTINUED RADIATIONAL COOLING
UNDER MCLEAR SKIES AND A LIGHT WIND WILL CAUSE VALLEY FOG TO
BECOME MORE WIDESPREAD ACROSS CENTRAL PA WITH LOCALLY DENSE FOG
EXPECTED...ESP IN THE DEEP RIVER/STREAM VALLEYS OF THE
ALLEGHENIES. MINS TEMPS WILL RANGE FROM NEAR 60F ACROSS THE NW
MTNS...TO NR 70F IN THE VALLEYS EAST OF THE ALLEGHENIES.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/...
ANY EARLY AM FOG SHOULD BURN OFF BY 13Z-14Z BASED ON CLIMATOLOGY
AND LATEST HRRR OUTPUT. FOCUS THEN SHIFTS TOWARD POTENTIAL OF SCT
DIURNAL CONVECTION ACROSS SOUTHEAST PA. PWATS ARE PROJECTED TO
APPROACH 2 INCHES IN THIS AREA AND HEATING OF THIS MOIST/UNSTABLE
AIR MASS SHOULD RESULT IN MODERATE CAPES OF ARND 2000J/JG ACROSS
THE LOWER SUSQ VALLEY BASED ON LATEST OPER MODEL AND GEFS OUTPUT.
SCT PULSE-TYPE TSRA SHOULD DEVELOP ACROSS THE SOUTHERN COUNTIES AS
CONVECTIVE TEMP IS REACHED DURING THE AFTN. WILL HAVE TO WATCH FOR
LOCALLY EXCESSIVE RAINFALL...AS ANY STORMS WILL BE SLOW-MOVERS DUE
TO WEAK FLOW ALOFT. CONVECTION-ALLOWING MDL DATA HINTS AT THIS
POTENTIAL WITH SPOT AMTS OF OVR 3 INCHES ACROSS THE LOWER SUSQ
VALLEY.
GEFS 925/850 TEMPS SUPPORT HIGH TEMPS IN THE M-U80S...WITH THE
GREATEST DEPARTURES FROM AVERAGE ACROSS THE W MTNS. WHEN COMBINED
WITH HIGH HUMIDITY...APPARENT TEMPS WILL RANGE FROM THE U80S TO
L90S...PERHAPS THE WARMEST WE/LL SEE UNTIL NEXT YEAR.
A COLD FRONT WILL BE APPROACHING FROM THE GREAT LAKES ON FRIDAY
NIGHT AND PUSH THRU DURING THE DAY SAT. THE POPS WILL STAY RATHER
LOW OVER MOST OF THE AREA WITH ONLY SCT SHRA/TSRA OVERNIGHT...AND
MAINLY LIMITED TO THE NW ZONES. THE NWRN COUNTIES WILL LIKELY SEE
STORMS MOVE DOWN FROM THE NW AFTER MIDNIGHT...BEFORE GRADUALLY
WEAKENING AS THEY APPROACH THE RIDGE AND VALLEY REGION OF CENTRAL
PENN.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
*SHOWERS/TSTMS ON SATURDAY FOLLOWED BY COOLER/DRY WEATHER SUNDAY
INTO MONDAY
*NEAR AVERAGE TEMPERATURES AND MORE UNSETTLED CONDITIONS TUE-THU
THE REGIONAL PATTERN ALOFT WILL FEATURE INCREASING TROUGHINESS
THROUGH THE MEDIUM RANGE PERIOD...WITH THE GLOBAL ENSEMBLE MEANS
SHOWING A CORE OF NEGATIVE HEIGHT ANOMALIES OVER THE UPPER MIDWEST
AND GREAT LAKES REGIONS BY THE MIDDLE TO LATER PART OF NEXT WEEK
/SEPT 11-12TH/. OVERALL...THE NAEFS/GEFS AND ECENS ALL SIGNAL A
TRANSITION TOWARD A HIGHER AMPLITUDE PATTERN PARTICULARLY ACROSS
SOUTH CENTRAL CANADA.
AN ELONGATED COLD FRONT TRAILING A RELATIVELY STRONG SFC LOW OVER
NEWFOUNDLAND/LABRADOR WILL BE THE FOCUS FOR SHOWERS/TSTMS AS IT
CROSSES THE APPALACHIANS ON SAT. A MODIFIED CANADIAN HIGH BUILDING
SWD INTO THE CENTRAL PLAINS WILL EVENTUALLY SHIFT EWD THROUGH THE
NORTHEAST STATES AND MOVE INTO THE MARITIMES BY NEXT WED.
WEAK HEIGHT FALLS WILL OVERSPREAD THE REGION ON SAT...AS A POSITIVE
TILT S/WV TROUGH MOVES EWD FROM THE NRN PLAINS ACROSS THE GREAT
LAKES REGION. ABOVE NORMAL PWS ALONG/AHEAD OF THE LOW LEVEL BOUNDARY
AND SUFFICIENT HEATING/INSTABILITY SHOULD FOSTER NRMS SHOWERS AND
SCT TSTMS WITH SOME LOCALLY HEAVY DOWNPOURS. WITH THE STRONGEST BELT
OF MID-LEVEL FLOW AND DEEP-LAYER SHEAR EXPECTED TO REMAIN NORTH OF
THE AREA ACROSS ONT/QUE AND NRN NEW ENGLAND...THE RISK FOR SVR
STORMS IS LOW. THE PCPN WILL END FROM NW-SE SAT NGT WITH MUCH
DRIER AIR FILTERING IN FOR SUNDAY. DRY WX SHOULD CONTINUE INTO
EARLY NEXT WEEK BEFORE CONDS TURN MORE UNSETTLED. EASTERLY WINDS
TO THE SOUTH OF HP CELL MOVG INTO THE MARITIMES ARE SUGGESTIVE OF
A COOL-AIR WEDGE OVER THE MID-ATLC WHICH SHOULD DAYTIME HIGHS NEAR
AVG.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
OBS AND SATL IMAGERY SHOWING VALLEY FOG ACROSS NORTHWEST PA EARLY
THIS MORNING. CONTINUED RADIATIONAL COOLING UNDER MCLEAR SKIES
AND A LIGHT WIND WILL CAUSE VALLEY FOG AND A THIN STRATOCU DECK TO
BECOME MORE WIDESPREAD ACROSS CENTRAL PA WITH LOCALLY DENSE FOG
EXPECTED...ESP IN THE DEEP RIVER/STREAM VALLEYS OF THE
ALLEGHENIES. MANY LOCATIONS LIKELY TO EXPERIENCE A PERIOD OF IFR-
LIFR CONDS NEAR DAWN.
FOG SHOULD BURN OFF BY 14Z...WITH HAZE POTENTIALLY LINGERING
THROUGH MID/LATE MORNING IN THE SE. FOCUS THEN SHIFTS TOWARD
POTENTIAL FOR SCT DIURNAL CONVECTION ACROSS SOUTHEAST PA. PWATS
ARE PROJECTED TO APPROACH 2 INCHES IN THIS AREA AND HEATING OF
THIS MOIST/UNSTABLE AIR MASS SHOULD RESULT IN MODERATE CAPES OF
ARND 2000J/JG ACROSS THE LOWER SUSQ VALLEY BASED ON LATEST OPER
MODEL AND GEFS OUTPUT. SCT PULSE- TYPE TSRA SHOULD DEVELOP ACROSS
THE SOUTHERN COUNTIES BRINGING LOCAL RESTRICTIONS AS CONVECTIVE
TEMP IS REACHED DURING THE AFTN...AND ANY STORMS WILL BE SLOW-
MOVERS DUE TO WEAK FLOW ALOFT.
OUTLOOK...
SAT...AM SHRA/LOW CIGS POSS NW MTNS. PM TSRA IMPACTS POSS
ELSEWHERE.
SUN...AM FOG POSS NW MTNS.
MON...PATCHY AM VALLEY FOG POSS.
TUE...CHC SHOWERS/TSTMS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD/LAMBERT
LONG TERM...STEINBUGL
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
235 AM EDT FRI SEP 5 2014
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO DRIFT EAST OF THE MID ATLANTIC
SEABOARD TONIGHT BRINGING VERY WARM AND HUMID CONDITIONS FOR
FRIDAY. A COLD FRONT WILL MOVE EAST FROM THE OHIO VALLEY AND
CROSS THE STATE SATURDAY AFTERNOON AND EVENING. A REFRESHINGLY
COOLER AND MUCH DRIER AIRMASS WILL OVERSPREAD THE REGION FOR
SUNDAY AND MONDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
11-3.9 MICRON SATL IMAGERY ALREADY SHOWING THE PRESENCE OF VALLEY
FOG ACROSS NORTHWEST PA AT 06Z. CONTINUED RADIATIONAL COOLING
UNDER MCLEAR SKIES AND A LIGHT WIND WILL CAUSE VALLEY FOG TO
BECOME MORE WIDESPREAD ACROSS CENTRAL PA WITH LOCALLY DENSE FOG
EXPECTED...ESP IN THE DEEP RIVER/STREAM VALLEYS OF THE
ALLEGHENIES. MINS TEMPS WILL RANGE FROM NEAR 60F ACROSS THE NW
MTNS...TO NR 70F IN THE VALLEYS EAST OF THE ALLEGHENIES.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/...
ANY EARLY AM FOG SHOULD BURN OFF BY 13Z-14Z BASED ON CLIMATOLOGY
AND LATEST HRRR OUTPUT. FOCUS THEN SHIFTS TOWARD POTENTIAL OF SCT
DIURNAL CONVECTION ACROSS SOUTHEAST PA. PWATS ARE PROJECTED TO
APPROACH 2 INCHES IN THIS AREA AND HEATING OF THIS MOIST/UNSTABLE
AIR MASS SHOULD RESULT IN MODERATE CAPES OF ARND 2000J/JG ACROSS
THE LOWER SUSQ VALLEY BASED ON LATEST OPER MODEL AND GEFS OUTPUT.
SCT PULSE-TYPE TSRA SHOULD DEVELOP ACROSS THE SOUTHERN COUNTIES AS
CONVECTIVE TEMP IS REACHED DURING THE AFTN. WILL HAVE TO WATCH FOR
LOCALLY EXCESSIVE RAINFALL...AS ANY STORMS WILL BE SLOW-MOVERS DUE
TO WEAK FLOW ALOFT. CONVECTION-ALLOWING MDL DATA HINTS AT THIS
POTENTIAL WITH SPOT AMTS OF OVR 3 INCHES ACROSS THE LOWER SUSQ
VALLEY.
GEFS 925/850 TEMPS SUPPORT HIGH TEMPS IN THE M-U80S...WITH THE
GREATEST DEPARTURES FROM AVERAGE ACROSS THE W MTNS. WHEN COMBINED
WITH HIGH HUMIDITY...APPARENT TEMPS WILL RANGE FROM THE U80S TO
L90S...PERHAPS THE WARMEST WE/LL SEE UNTIL NEXT YEAR.
A COLD FRONT WILL BE APPROACHING FROM THE GREAT LAKES ON FRIDAY
NIGHT AND PUSH THRU DURING THE DAY SAT. THE POPS WILL STAY RATHER
LOW OVER MOST OF THE AREA WITH ONLY SCT SHRA/TSRA OVERNIGHT...AND
MAINLY LIMITED TO THE NW ZONES. THE NWRN COUNTIES WILL LIKELY SEE
STORMS MOVE DOWN FROM THE NW AFTER MIDNIGHT...BEFORE GRADUALLY
WEAKENING AS THEY APPROACH THE RIDGE AND VALLEY REGION OF CENTRAL
PENN.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
*SHOWERS/TSTMS ON SATURDAY FOLLOWED BY COOLER/DRY WEATHER SUNDAY
INTO MONDAY
*NEAR AVERAGE TEMPERATURES AND MORE UNSETTLED CONDITIONS TUE-THU
THE REGIONAL PATTERN ALOFT WILL FEATURE INCREASING TROUGHINESS
THROUGH THE MEDIUM RANGE PERIOD...WITH THE GLOBAL ENSEMBLE MEANS
SHOWING A CORE OF NEGATIVE HEIGHT ANOMALIES OVER THE UPPER MIDWEST
AND GREAT LAKES REGIONS BY THE MIDDLE TO LATER PART OF NEXT WEEK
/SEPT 11-12TH/. OVERALL...THE NAEFS/GEFS AND ECENS ALL SIGNAL A
TRANSITION TOWARD A HIGHER AMPLITUDE PATTERN PARTICULARLY ACROSS
SOUTH CENTRAL CANADA.
AN ELONGATED COLD FRONT TRAILING A RELATIVELY STRONG SFC LOW OVER
NEWFOUNDLAND/LABRADOR WILL BE THE FOCUS FOR SHOWERS/TSTMS AS IT
CROSSES THE APPALACHIANS ON SAT. A MODIFIED CANADIAN HIGH BUILDING
SWD INTO THE CENTRAL PLAINS WILL EVENTUALLY SHIFT EWD THROUGH THE
NORTHEAST STATES AND MOVE INTO THE MARITIMES BY NEXT WED.
WEAK HEIGHT FALLS WILL OVERSPREAD THE REGION ON SAT...AS A POSITIVE
TILT S/WV TROUGH MOVES EWD FROM THE NRN PLAINS ACROSS THE GREAT
LAKES REGION. ABOVE NORMAL PWS ALONG/AHEAD OF THE LOW LEVEL BOUNDARY
AND SUFFICIENT HEATING/INSTABILITY SHOULD FOSTER NRMS SHOWERS AND
SCT TSTMS WITH SOME LOCALLY HEAVY DOWNPOURS. WITH THE STRONGEST BELT
OF MID-LEVEL FLOW AND DEEP-LAYER SHEAR EXPECTED TO REMAIN NORTH OF
THE AREA ACROSS ONT/QUE AND NRN NEW ENGLAND...THE RISK FOR SVR
STORMS IS LOW. THE PCPN WILL END FROM NW-SE SAT NGT WITH MUCH
DRIER AIR FILTERING IN FOR SUNDAY. DRY WX SHOULD CONTINUE INTO
EARLY NEXT WEEK BEFORE CONDS TURN MORE UNSETTLED. EASTERLY WINDS
TO THE SOUTH OF HP CELL MOVG INTO THE MARITIMES ARE SUGGESTIVE OF
A COOL-AIR WEDGE OVER THE MID-ATLC WHICH SHOULD DAYTIME HIGHS NEAR
AVG.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS SKIES CLEAR TONIGHT...AND AS WINDS LIGHTEN...LOCALLY DENSE AND
MAINLY DEEPER VALLEY FOG IS POSSIBLE LATE TONIGHT THROUGH MID
FRIDAY MORNING. MANY LOCATIONS LIKELY TO EXPERIENCE A PERIOD OF
IFR-LIFR CONDS NEAR DAWN FRIDAY.
CONDITIONS WILL GRADUALLY IMPROVE LATE FRI MORNING AND AFTERNOON
WITH A FEW AREAS OF MVFR HAZE LINGERING /ESPECIALLY INVOF KMDT AND
KLNS/. ISOLATED SHRA/TSRA FRIDAY AFTERNOON WILL BRING THE
POTENTIAL FOR BRIEF MVFR CONDITIONS.
OUTLOOK...
FRI...PATCHY AM FOG. ISOLD PM TSRA IMPACTS POSS SOUTHERN PA.
SAT...AM SHRA/LOW CIGS POSS NW MTNS. PM TSRA IMPACTS POSS ELSEWHERE.
SUN...AM FOG POSS NW MTNS.
MON...PATCHY AM VALLEY FOG POSS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD/LAMBERT
LONG TERM...STEINBUGL
AVIATION...LAMBERT/CERU
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
320 AM CDT FRI SEP 5 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 320 AM CDT FRI SEP 5 2014
THE MAIN FOCUS IN THE SHORT TERM IS ON THE PRECIPITATION/TEMPERATURE/DEW
POINT TRENDS AS A COLD FRONT MOVES THROUGH THE REGION.
CURRENTLY...A SURFACE COLD FRONT EXTENDS FROM THE WESTERN UP OF
MICHIGAN DOWN THROUGH SOUTHWEST WISCONSIN AND SOUTH CENTRAL IOWA.
THE AIR MASS BEHIND THIS FRONT IS MUCH COOLER AND LESS HUMID WITH
TEMPERATURES DROPPING FROM THE UPPER 70S TO THE MID 50S AND DEW
POINTS GOING FROM THE MID 70S TO THE UPPER 40S. WHILE THE
ENVIRONMENT IN THE WARM SECTOR IS CAPPED OFF...SOME SLOPING LOW
LEVEL FRONTOGENESIS IS BEING AIDED BY A MID LEVEL TROUGH DIGGING
ACROSS NORTH DAKOTA/NORTHERN MINNESOTA AND HAS PRODUCED A BAND OF
CONVECTION ACROSS THE NORTHERN HALF OF IOWA. THIS RAIN WILL TRACK
TO THE NORTHEAST/EAST THIS MORNING BUT LIKELY WEAKEN AS IT LEAVES
THE DEEPER FORCING IN CENTRAL IOWA. THE 05.07Z RAP SHOWS THAT THE
0-3KM MUCAPE DROPS QUITE A BIT ONCE YOU REACH THIS
PRECIPITATION AND VERTICAL SHEAR PROFILES SHOW ONLY ABOUT 20-30KTS
OF 0-6KM SHEAR WITH MUCH OF IT AROUND 900-750MB. BASED ON
THIS...AM NOT EXPECTING MUCH IN THE WAY OF SEVERE WEATHER BUT
THAT THERE WILL BE A PERIOD OF LIGHT TO MODERATE
RAINFALL...PARTICULARLY ACROSS NORTHEAST IOWA AND FAR SOUTHWEST
WISCONSIN.
CLOUD COVER WILL LIKELY LINGER THROUGH MUCH OF THE DAY AS ANOTHER
MID LEVEL SHORT WAVE TROUGH TRACKS TO THE EAST FROM EASTERN
COLORADO/WESTERN NEBRASKA ON THROUGH IOWA TODAY. 06.00Z NAM/GFS
FORECAST SOUNDINGS SHOW A SATURATING MID LEVEL LAYER WITH DRY AIR
STUCK UNDERNEATH IT. WHILE THE FOCUS APPEARS TO MAINLY BE ACROSS
THE SOUTHERN HALF OF IOWA INTO TONIGHT...THE 05.00Z NAM/GFS/ECMWF
DO HINT AT SOME LIGHT QPF MAKING IT INTO THE REGION. CONFIDENCE IS
NOT HIGH ENOUGH RIGHT NOW WITH WHAT WILL WIN OUT IN THIS BATTLE OF
DRY AIR...SO HAVE KEPT THE FORECAST DRY INTO TONIGHT FOR THE TIME
BEING.
OTHERWISE...HIGH TEMPERATURES HAVE ALREADY BEEN HIT FOR THE DAY AS
THEY WILL DROP INTO THIS MORNING AND THEN MAKE A SMALL DIURNAL
BUMP THIS AFTERNOON BEFORE DROPPING QUICKLY TONIGHT. LOW LEVEL
WINDS LOOK LIKE THEY SHOULD BE STRONG ENOUGH TO KEEP ANY VALLEY
FOG FROM FORMING...BUT WILL HAVE TO MONITOR THE CONDITIONS INTO
TONIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 320 AM CDT FRI SEP 5 2014
FAIRLY QUIET EXTENDED PERIOD WITH THE COOLER TEMPERATURES THE MAIN
STORY. THE COOLEST PERIOD APPEARS TO BE THIS WEEKEND AS +6C TO +8C
850MB AIR SITS OVER THE REGION BEFORE WARMER AIR GETS ADVECTED IN
ON THE BACK SIDE OF THE RIDGE EARLY NEXT WEEK. THE NEXT CHANCES
FOR PRECIPITATION ARE ON MONDAY INTO THURSDAY AS A MID LEVEL
SHORT WAVE TROUGH MOVES THROUGH THE REGION. NOT MUCH INSTABILITY
TO WORK WITH AS THE 05.00Z GFS/ECMWF SHOW LESS THAN 1000 J/KG OF
0-3KM MUCAPE AROUND THE REGION SO DO NOT EXPECT MUCH IN THE WAY
OF WIDESPREAD THUNDERSTORMS...PARTICULARLY ANYTHING CONSIDERED
SEVERE.
A MORE SIGNIFICANT COLD PUSH LOOKS LIKE IT WILL MOVE IN ON
THURSDAY WITH 850MB TEMPERATURES DROPPING BELOW 0C. THIS WILL
LIKELY LEAD TO SOME LOW TEMPERATURES DIPPING INTO THE 30S GOING
INTO FRIDAY MORNING AND THE POTENTIAL FOR SOME FROST IN THE
TYPICAL LOW/COLD BOG AREAS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1126 PM CDT THU SEP 4 2014
COLD FRONT IS MAKING ITS WAY THROUGH THE TAF SITES EARLY THIS
MORNING. THERE HAS BEEN A BRIEF BATCH OF MVFR STRATUS DEVELOPING
IN THE WAKE OF THE FRONT...LIKELY A RESULT OF THE COOLER AIR
COMING IN QUICKER THAN THE HUMID AIR EXITING. THIS STRATUS SHOULD
BE OUT OF RST BY 07Z...WITH A POSSIBLE IMPACT TIME OF 07-09Z AT
LSE. THERE HAVE ALSO BEEN SHOWERS AND THUNDERSTORMS DEVELOPING
BEHIND THE FRONT...ESPECIALLY ACROSS IOWA. THESE ARE SPREADING
NORTHEAST AND COULD BE SOUTH OF OR NEAR LSE FOR THE 06-10Z PERIOD.
THEREFORE...HAVE A VCSH COVERING THIS.
AFTER 10Z...DRIER AIR OVER WESTERN MN WILL COME INTO THE TAF
SITES ON A 10 KT NORTHWEST WIND...RESULTING IN VFR CONDITIONS FOR
THE REST OF THE TAF PERIOD.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
305 AM CDT FRI SEP 5 2014
.TODAY...FORECAST CONFIDENCE IS MEDIUM.
THE MAIN ISSUE FOR TODAY IS THE ARRIVAL OF A STRONG COLD FRONT EARLY
THIS MORNING...EXITING EAST OF MILWAUKEE BY LATE MORNING. AN AREA
OF WEAKENING CONVECTION OVER IOWA EARLY THIS MORNING IS BEING PICKED
UP BY THE HRRR AND TRACKED ACROSS THE FORECAST AREA THIS
MORNING...MOSTLY BEFORE 8 AM. THE HRRR ALSO SUGGESTS INTENSIFICATION
AND EXPANSION. THIS ACTIVITY IS FOCUSED ALONG THE H8 COLD
FRONT...WHICH IS POST FRONTAL OF THE SFC FRONT. THE CONCERN IS IT
MAY CATCH UP WITH THE SFC FRONT OVER OUR WRN CWA THIS MORNING AND
BECOME MORE SFC BASED. INSTABILITY IS PRETTY HIGH ACROSS THE AREA
RIGHT NOW...SO WILL HAVE TO WATCH TRENDS VERY CLOSELY. THERE IS A
DISTINCT LACK OF MID AND UPPER LEVEL SUPPORT AND DEEP LAYER SHEAR IS
RATHER WEAK. WILL HANG ONTO A CHANCE FOR STORMS UNTIL THE FRONT
EXITS.
THEN SOME MID LEVEL FORCING FROM AN APPROACHING SHORT WAVE COULD
RESULT IN SOME INCREASING SHOWERS SHOWERS AND ISOLATED THUNDERSTORMS
ACROSS THE SOUTHEAST THIS AFTERNOON AND INTO THE EVENING HOURS. THIS
WILL ALL BE POST FRONTAL WITH A DECENT RIGHT REAR UPPER JET QUADRANT
HELPING TO SUPPORT DECENT 700-600MB FRONTOGENESIS. THE MAIN
QUESTION IS WHETHER THERE/LL BE ENOUGH DEEP MOISTURE LEFT TO SUPPORT
SHOWERS. SOME OF THE MODELS SCOUR OUT THE RAIN ONCE THE FRONT
EXITS...OTHERS DO THE POST FRONTAL GIG...SO WILL HANG ONTO POPS SE.
COOLER AND DRIER AIR WILL CONTINUE TO OVERSPREAD THE AREA AS THE DAY
PROGRESSES.
.TONIGHT...FORECAST CONFIDENCE IS HIGH.
OTHER THAN SOME LINGERING EVENING SHOWERS POSSIBLE IN THE
SOUTHEAST...THE COOLER...DRIER TREND WILL CONTINUE. SKIES WILL
GRADUALLY CLEAR WITH LOWS DIPPING INTO THE LOWER 50S OVER ALL BUT
THE SOUTHEAST. THE CLOUDS CLEARING LATER ACROSS THE SOUTHEAST WILL
KEEP TEMPS UP A BIT HIGHER.
.SATURDAY AND SUNDAY - CONFIDENCE...MEDIUM
HIGH PRESSURE IN THE CENTRAL PLAINS SATURDAY WILL EXPAND ACROSS THE
GREAT LAKES SUNDAY. NORTHWEST WINDS AND THERMAL TROUGH LINGERS THROUGH
SATURDAY EVENING. SUBTLE MODIFICATION FOR SUNDAY AS 850 TEMPS MODIFY
ONLY SLIGHTLY. LIGHT WIND REGIME WITH SURFACE HIGH WELL IN PLACE AND
GRADIENT WEAK.
.MONDAY - CONFIDENCE...MEDIUM
MODELS SHOW 500 MILLIBAR TROUGH APPROACHING INTO IA/MN BY END OF THE
DAY. 850 JET AXIS REMAINS WEST AND LIKE THE DRY LOOK FOR SRN WI.
WITH HIGH TO THE EAST THE FLOW WILL BECOME DECIDEDLY FROM THE
SOUTH...SO GRADUAL MOISTURE ADVECTION THOUGH BEST PUSH OF THIS HOLDS
OFF TO OUR WEST DURING THE DAY.
.MONDAY NIGHT AND TUESDAY - CONFIDENCE...MEDIUM
BETTER MOISTURE ADVECTION THIS PERIOD THOUGH LLJ PROGGD BY BOTH
THE GFS AND ECMWF TO COLLAPSE TO OUR SOUTH. BUT THERE IS SOME
MOISTURE ADVECTION WITH THE INFLUENCE OF THE SHORTWAVE TROUGH. 00Z
ECMWF SHOWS THE LEAST QPF WITH THIS SYSTEM WHILE THE GFS AND GEM
SHOW A BIT MORE OF A NORTHERN MAX ACROSS OUR AREA, ALL MODELS
SUGGEST BEST CONVECTION WILL BE FURTHER SOUTH SHIFTING FROM THE
CENTRAL PLAINS INTO THE MID MISSISSIPPI VALLEY. OVERALL SURFACE
PATTERN WEAK THOUGH INCREASED FORCING VIA UPPER WAVE AND MORE
MOISTURE WILL LEAD TO MAINTAINING THE TRENDS OF THE ALLBLEND POPS.
.WEDNESDAY AND THURSDAY - CONFIDENCE...LOW
WHILE DETAILS ARE YET TO GET WORKED OUT...THE GENERAL IDEA OF THE
GFS AND ECMWF IS TO TAKE AN ORGANIZING LOW PRESSURE SYSTEM FROM
VCNTY OF THE CNTRL PLAINS INTO THE EASTERN LAKES. THE TREND IS FOR
A SOUTHERN TRACK WHICH KEEPS US ON THE COOL SIDE WITH A GREATER
LIKELIHOOD FOR A FALL-LIKE STEADIER RAIN SETUP THOUGH
TIMING...TRACK AND STRENGTH OF LOW STILL VARIABLE AMONGST THE
MODELS.
&&
.AVIATION/12Z TAFS/...LOOK FOR VFR CONDITIONS THROUGH THE TAF PERIOD.
A COLD FRONT WILL SWEEP THROUGH MADISON AROUND 11-12Z THIS MORNING
AND REACH MILWAUKEE AROUND 14Z. WE COULD SEE SHOWERS AND THUNDERSTORMS
EXPAND ALONG THE FRONT THIS MORNING AS SOME WEAK CONVECTION MOVES
NORTHEAST OUT OF IOWA. CONDITIONS COULD BRIEFLY DROP TO MVFR LEVELS
IN ANY STRONGER STORMS. MORE POST FRONTAL SHOWERS AND STORMS ARE
POSSIBLE ACROSS THE SOUTHEAST WISCONSIN TAF SITES LATER THIS AFTERNOON
AND INTO THE EVENING AS A WEAK MID LEVEL WAVE MOVES BY. OTHERWISE...
LOOK FOR CLEARING SKIES FROM NORTHWEST TO SOUTHEAST OVERNIGHT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...DAVIS
SATURDAY THROUGH THURSDAY...COLLAR
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1126 PM CDT THU SEP 4 2014
.UPDATE...
ISSUED AT 855 PM CDT THU SEP 4 2014
CONFIDENCE IS LOWERING ON POTENTIAL FOR SHOWERS AND THUNDERSTORMS
TONIGHT. LATEST SURFACE ANALYSIS SHOWS A COLD FRONT FROM NEAR
MENOMONIE WI TO WABASHA MN AND CHARLES CITY IA. RAP SHOWS LESS
THAN 25 J/KG CIN ACROSS MUCH OF THE FORECAST
AREA...HOWEVER...SURFACE BASED CIN IS MORE ON THE ORDER OF 50-75
J/KG. THIS CIN REFLECTS CAPPING IN PLACE SEEN ON THE 00Z MPX
SOUNDING. STILL WAITING TO SEE IF FRONTOGENESIS ON AND BEHIND THE
COLD FRONT CAN INITIATE CONVECTION. CERTAINLY PLENTY OF
INSTABILITY SHOULD THE CAP WEAKEN AS ALSO SEEN ON THE 00Z MPX
SOUNDING...THUS CANNOT REMOVE CHANCES COMPLETELY FOR THE REST OF
TONIGHT. SHOULD CONVECTION DEVELOP...AN ISOLATED SEVERE STORM IS
POSSIBLE...PARTICULARLY HERE DURING THE EVENING HOURS. AFTER
MIDNIGHT...CAPE DIMINISHES WHICH WILL LIMIT SEVERE POTENTIAL.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 327 PM CDT THU SEP 4 2014
MAIN FORECAST CONCERNS ARE ON THE POTENTIAL FOR SEVERE THUNDERSTORMS.
LATEST SURFACE ANALYSIS PLACED LOW PRESSURE OVER CENTRAL
MINNESOTA...EDGING EAST. A COLD FRONT EXTENDED SOUTHWARD INTO WESTERN
IOWA WHILE A WARM FRONT WAS POSITIONED NEAR THE INTERSTATE 94
CORRIDOR IN EAST CENTRAL MINNESOTA THROUGH WESTERN WISCONSIN.
EXTENSIVE CLOUD COVER OVER MUCH OF THE FORECAST AREA WAS HELPING TO
HOLD TEMPERATURES DOWN A BIT. SHOWERS AND STORMS ARE DEVELOPING
ACROSS AREAS NORTH OF INTERSTATE 90 DESPITE A FAIRLY STOUT CAP IN
PLACE. FORECAST SOUNDINGS ARE INDICATING 750 MB TEMPERATURES
HOVERING RIGHT AROUND 15 C. SOUNDINGS SUGGEST THIS CAP WILL WEAKEN
AS A SHORTWAVE APPROACHES FROM NEBRASKA/SOUTH DAKOTA THIS AFTERNOON
INTO THIS EVENING JUST AS THE COLD FRONT IS MAKING ITS WAY INTO
NORTHWESTERN SECTIONS OF THE FORECAST AREA. MESOSCALE MODELS ARE
FIRING SHOWERS AND STORMS ALONG AND BEHIND THE FRONT THIS EVENING.
IF THIS SCENARIO PLAYS OUT...THE MAIN THREATS FROM THE STORMS WOULD
BE LARGE HAIL AND HEAVY RAINFALL. WE SHOULD SEE A BAND OF SHOWERS
AND STORMS DEVELOP RIGHT OVER THE FORECAST AREA THIS EVENING THEN
THIS BAND WILL GRADUALLY PUSH SOUTHEAST DURING THE OVERNIGHT HOURS
AS THE FRONT SAGS SOUTHWARD. MUCH COOLER AIR PUSHES INTO THE
FORECAST AREA IN THE WAKE OF THE FRONT TONIGHT INTO FRIDAY WITH 850
MB TEMPS GOING FROM 25 C THIS AFTERNOON TO AROUND 10 C BY FRIDAY
AFTERNOON. A VERY COMFORTABLE DAY IS IN STORE FOR THE REGION ON
FRIDAY AS HIGH PRESSURE BUILDS IN FROM THE WEST. PLAN PARTLY SUNNY
SKIES ACROSS THE REGION WITH HIGHS RANGING FROM THE MID 60 TO LOWER
70S.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 327 PM CDT THU SEP 4 2014
HIGH PRESSURE REMAINS IN CONTROL FRIDAY NIGHT INTO SUNDAY AS THE
REGION REMAINS IN A COOL NORTHWEST FLOW REGIME. WITH THE RIDGE AXIS
NEARBY PROVIDING LIGHT AND VARIABLE WINDS FROM THE SURFACE THROUGH 2
KFT MAY SET THE STAGE FOR AREAS OF FOG LATE SATURDAY NIGHT INTO
SUNDAY MORNING. HAVE INCLUDED PATCHY FOG ALONG RIVER VALLEY
LOCATIONS AND OVER CENTRAL WISCONSIN DURING THIS TIMEFRAME. THE NEXT
CHANCE FOR SHOWERS AND STORMS ACROSS THE REGION ARRIVES ON MONDAY AS
FLOW ALOFT TURNS MORE ZONAL AND A SHORTWAVE TROUGH MOVES IN FROM THE
PLAINS. TEMPERATURES WILL REMAIN SEASONABLY COOL THROUGH THE PERIOD
WITH HIGHS MAINLY IN THE 70S. A MORE UNSETTLED PATTERN IS EXPECTED
TO DEVELOP NEXT WEEK AND WILL REMAIN OVER THE REGION THROUGH
THURSDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1126 PM CDT THU SEP 4 2014
COLD FRONT IS MAKING ITS WAY THROUGH THE TAF SITES EARLY THIS
MORNING. THERE HAS BEEN A BRIEF BATCH OF MVFR STRATUS DEVELOPING
IN THE WAKE OF THE FRONT...LIKELY A RESULT OF THE COOLER AIR
COMING IN QUICKER THAN THE HUMID AIR EXITING. THIS STRATUS SHOULD
BE OUT OF RST BY 07Z...WITH A POSSIBLE IMPACT TIME OF 07-09Z AT
LSE. THERE HAVE ALSO BEEN SHOWERS AND THUNDERSTORMS DEVELOPING
BEHIND THE FRONT...ESPECIALLY ACROSS IOWA. THESE ARE SPREADING
NORTHEAST AND COULD BE SOUTH OF OR NEAR LSE FOR THE 06-10Z PERIOD.
THEREFORE...HAVE A VCSH COVERING THIS.
AFTER 10Z...DRIER AIR OVER WESTERN MN WILL COME INTO THE TAF
SITES ON A 10 KT NORTHWEST WIND...RESULTING IN VFR CONDITIONS FOR
THE REST OF THE TAF PERIOD.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...AJ
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
950 AM EDT FRI SEP 5 2014
.UPDATE...
CURRENT...WEAK SURFACE TROUGH OVHD YESTERDAY HAS LIFTED N-NE AND NOW
EXTENDS FROM N FL NEWD INTO COASTAL GA/SC/NC. WEAK LOW CENTER NEAR
THE GA COAST IS PRODUCING WIDESPREAD CONVECTION WELL OFFSHORE FROM
ABOUT KDAB N-NEWD. NE H25 WINDS ARE BLOWING MUCH OF ITS CONVECTIVE
DEBRIS CLOUDS SWWD INTO ECFL. BEHIND (SOUTH OF) THIS FEATURE...THE
ATLC RIDGE IS BUILDING WWD INTO SOUTH CTRL WITH ITS AXIS NR THE LAKE
OKEE REGION. LOOKING ALOFT...THERE IS STILL SOME DECENT REFLECTION
OF THE MID LVL TROUGH OVHD AS SEEN IN WATER VAPOR AND THE RUC H50
VORT/STRMLN ANLYS. WEAK LIFT ASCD WITH THE VORT LOBE IS HELPING TO
MAINTAIN THE MID LEVEL AS/AC DECK NEAR/NORTH OF A KSRQ-KMCO-KDAB
LINE.
MORNING RAOBS SHOW PWATS IN THE 2.0" TO 2.1" OVER THE ENTIRETY OF
THE PENINSULA...WITH H50 TEMPS OF -6C TO -8C LEADING TO SOMEWHAT
ANEMIC LAPSE RATES. THIS IN TURN POINTS TO HEAVY RAIN/LIGHTNING AS
THE PRIMARY STORM THREATS TODAY. LIGHT STEERING WINDS ACROSS THE NRN
HALF CWA BECOMING INCREASINGLY OUT OF THE SW AT AROUND 10KT OVER THE
SRN HALF AS WHAT`S LEFT OF THE MID LEVEL VORT AXIS CONTINUES TO LIFT
NORTH.
POP DISTRIBUTION IN THE GRIDS/ZFP LOOKS PRETTY GOOD. WHILE STRONGER
STEERING FLOW TOWARD THE NE IS IN PLACE OVER THE FAR SERN CWA...THIS
WILL COUNTERACTED BY A MORE RAPID INLAND PUSH TO THE ECSB...SO LOWER
(40 ALONG THE IMMEDIATE ST LUCIE/MARTIN COAST) LOOKS OK THERE.
&&
.AVIATION...EXPECT INCREASING COVERAGE OF SHOWERS/STORMS AREAWIDE
DURING THE LATE MORNING AND AFTERNOON. ONCE AGAIN THE VRB-FPR-SUA
CORRIDOR LOOKS TO HAVE EARLIEST ONSET TIMES WITH INITIAL ECSB
FORMATION THERE (~16Z) SPREADING FARTHER NORTH/INLAND THEREAFTER.
&&
.MARINE...
S-SSW WINDS ACROSS THE MAOR WILL TEND TO BACK MORE TWD THE SSE-SE
THIS AFTERNOON AS ATLC RIDGING BUILDS IN BEHIND THE SFC LOW/TROUGH
TO THE NORTH..WITH A LITTLE MORE SYNOPTIC ONSHORE COMPONENT FARTHER
SOUTH. SPEEDS GENERALLY AOB 10KT WILL KEEP SEAS 2FT (OR A LITTLE
LESS) NEAR SHORE AND 2-3FT WELL OFFSHORE.
&&
UPDATE/AVIATION...CRISTALDI
RADAR/IMPACT WX....WIMMER
&&
.PREV DISCUSSION... /ISSUED 335 AM EDT FRI SEP 5 2014/
SAT...A MID LYR LOW ACROSS SE GA WILL MOVE LITTLE ON SATURDAY WITH
LOW LVL SOUTHERLY FLOW AND DEEP MOISTURE ACROSS E CENTRAL FL. THE
SOUTHERLY FLOW AND DEEP MOISTURE WILL ALLOW FOR DEVELOPMENT OF
MORNING SHOWERS AND AFTERNOON SHOWERS/THUNDERSTORMS WITH A
SLOW-MOVING EAST COAST SEA BREEZE MOVING MOVING TOWARD THE INTERIOR
IN THE AFTERNOON. WILL KEEP POPS MAINLY IN THE 50 PCT RANGE ALONG
THE COAST SOUTH OF THE CAPE AND UP TO 60 PCT ACROSS THE INTERIOR AND
NRN SECTIONS WHERE AFTERNOON STORMS MAY PUSH BACK TWD THE VOLUSIA
COAST IN THE AFTERNOON. WILL DROP TEMPS A FEW DEGREES FROM GFS MOS
HIGH TEMP FCSTS WHICH AGAIN SEEM TOO HIGH GIVEN EXPECTED
CONSIDERABLE CLOUD COVER AND HIGHER THAN NORMAL COVERAGE OF
SHOWERS/STORMS. HIGHS IN THE UPPER 80S COAST TO 90/LWR 90S OVER THE
INTERIOR.
SUNDAY...A FRONTAL BOUNDARY WILL STALL ACROSS GA WITH SFC LOW
PRESSURE OVER SC ON SUNDAY. DEEP MOISTURE WILL CONTINUE OVER THE
AREA WITH A BROAD RIDGE ACROSS THE ATLC ALLOWING FOR LOW LVL SSE
FLOW ACROSS FAR SRN SECTIONS AND SSW/SW FLOW ACROSS NRN LAKE AND
VOLUSIA COUNTIES. RAIN CHANCES WILL BE HIGHEST WEST OF NEW SMYRNA
BEACH TO KENANSVILLE LINE WHERE LIKELY AFTERNOON STORMS ARE
EXPECTED. FARTHER SOUTH ALONG THE TREASURE COAST THE EAST EAST COAST
SEA BREEZE WILL PUSH SLOWLY INLAND WITH 50 PCT RAIN CHANCES ACROSS
SRN BREVARD TO 40 PCT ACROSS COASTAL MARTIN. HIGHS UPPER 80S TO
AROUND 90 COAST TO LOWER 90S INTERIOR.
MONDAY...LOOKS TO BE A TRANSITION DAY TOWARD LOWER RAIN CHANCES INTO
MID WEEK. THE ATLC SFC RIDGE WILL KEEP LOW LVL FLOW FROM THE SE/S
AND HIGHEST RAIN CHANCES WILL OCCUR ACROSS THE INTERIOR WITH 40-50
PCT...AND LOWER ALONG THE COAST FROM 30-40 PCT. SHOULD BE MORE SUN
IN THE MORNING ALLOW HIGH TEMPS TO REACH AROUND 93 FOR THE INTERIOR
TO AROUND 90 ALONG THE EAST COAST.
TUE-FRI...THE ATLC RIDGE WILL BUILD WESTWARD INTO MID TO LATE WEEK
ACROSS E CENTRAL FL WITH LOW LVL SE/ESE FLOW DEVELOPING. 00Z GFS
MODEL INDICATES SOME PRONOUNCED DRYING MAKING ITS WAY ACROSS SRN
SECTIONS BY WED...WITH 00Z ECMWF SHOWING SOME DRIER AIR MAKING IT
HERE ABOUT 24 HOURS LATER BY THU. WILL SHOW A DECREASE IN RAIN
CHANCES BY MID TO LATE WEEK GENERALLY 30 PCT FOR THE COASTAL
COUNTIES AND 30-40 PCT OVER THE INTERIOR. THE DEVELOPING ONSHORE
FLOW SHOULD KEEP COASTAL HIGHS IN THE UPPER 80S TO NEAR 90 TO LOWER
90S ACROSS THE INTERIOR.
&&
.AVIATION...
NMRS SHRA/SCT TSRA OVER LCL ATLANTIC THIS MORNING WITH A FEW
BRUSHING COAST FROM KMLB NORTHWARDS...ESPECIALLY VCNTY KDAB.
ADDITIONAL ISOLD SHRA ALONG WEAK BOUNDARY NORTH OF ORLANDO METRO.
SCT SHRA/TSRA DEVELOPING ALONG COAST WITH EAST COAST SEA BREEZE
AFTER 15Z...AND WITH MORE QUICKLY INLAND MOVING WEST COAST SEA
BREEZE WEST OF ORLANDO METRO. COVERAGE BECOMING NMRS OVER INTERIOR
AND ALONG/NORTH OF I-4 CORRIDOR AFTER 19Z WITH BOUNDARY COLLISIONS
ESPECIALLY EAST/WEST SEA BREEZE LATE AFTN/EARLY EVE. A FEW STORMS
WILL PUSH BACK TO COAST NORTH OF KMLB THROUGH 06/03Z WITH ISOLD SHRA
VCNTY VOLUSIA COAST OVERNIGHT.
&&
.MARINE...
TODAY-TONIGHT...S-SW FLOW AROUND 10KTS THIS MORNING AS LCL ATLC GETS
PLACED ON THE BACKSIDE OF WEAK EASTERLY WAVE/TROUGH LIFTING NORTH
AROUND WEST SIDE OF ATLANTIC RIDGE. FLOW BECOMING S-SE 10-15KTS THIS
AFTERNOON...ESPECIALLY SOUTH OF SEBASTIAN INLET...WITH DEVELOPMENT
OF EAST COAST SEA BREEZE. S-SW 10-15KT OVERNIGHT INTO SAT MORN. SEAS
2-3FT THIS MORNING...BECOMING 2FT LATER TODAY AND TONIGHT. DOMINANT
PERIODS REMAIN FAIRLY SHORT WITH OFFSHORE COMPONENT TO FLOW...AROUND
7-8 SEC. SOUTHERLY COMPONENT WILL CONTINUE TO LEAD TO BAHAMAS
SHADOWING SOUTH OF SEBASTIAN INLET WITH 3-5SEC.
SAT-TUE...SOUTHERLY WINDS WILL INCREASE TO 10-15KT AT TIMES OVER THE
WEEKEND...WITH SEAS 2 FT NEAR THE COAST AND AROUND 3 FT OFFSHORE.
SCATTERED SHOWERS AND STORMS ARE EXPECTED OVER THE WATERS. THE ATLC
RIDGE WILL LIFT SLOWLY NORTHWARD NEXT WEEK ALLOWING WINDS TO BECOME
SE MON-TUE. SEAS ARE FORECAST TO REMAIN AROUND 2 FT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 90 75 90 75 / 60 50 60 40
MCO 92 75 92 74 / 60 40 60 30
MLB 90 76 89 75 / 50 40 50 30
VRB 90 74 89 75 / 50 30 40 30
LEE 91 76 90 76 / 70 30 60 30
SFB 91 76 92 76 / 60 40 60 40
ORL 91 77 91 76 / 60 40 60 40
FPR 89 74 89 74 / 40 30 40 30
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1053 AM CDT Fri Sep 5 2014
.UPDATE...
ISSUED AT 1047 AM CDT FRI SEP 5 2014
Cold front approaching the region and some scattered showers
popped up this morning on the nose of the llvl jet early...and
were gone. More showers and thunderstorms are possible into the
afternoon as the front approaches and just behind it. Until
then...hot and muggy conditions expected to continue with
southwesterly winds. Heat indices are expected to climb into the mid
90s and near 100 south of Interstate 70. Minor tweaks to the
forecast grids, but no major changes.
&&
.SHORT TERM...(Today)
ISSUED AT 328 AM CDT FRI SEP 5 2014
Cold front beginning to edge into east central Iowa early this
morning with most models pushing the boundary across our area during
the afternoon and early evening hours. One more hot and humid day
ahead of the cold front with temperatures ranging from the upper
80s far northwest to the lower 90s east central through southeast
Illinois. Forecast soundings showing the warm layer extending from
850-700 mb will gradually erode with time today which should allow
better coverage of convection along the frontal boundary despite
rather weak convergence. However, most models depict some robust
CAPES this afternoon with 3500-4500 J/KG forecast over central thru
east central Illinois. 0-6km bulk shear not very impressive until
you get behind the cold front, otherwise, most models indicate bulk
shear values of 15-20 kts in the warm section just ahead of the
front. Precipitable water values of around 2 inches still forecast
this afternoon so any storms that organize will produce torrential
rainfall in a short period of time, in addition to the possibility
for an isolated strong wind gust/wet microburst. Most of the
convective allowing models suggest the stronger convection will
begin to push into Indiana by late this afternoon or early this
evening and then begin to weaken.
&&
.LONG TERM...(Tonight through Friday)
ISSUED AT 328 AM CDT FRI SEP 5 2014
Cold front passes southeast of CWA this evening, while 00Z models
have trended slower with mid/upper level system/forcing tonight
into Saturday morning with showers and isolated thunderstorms likely
lingering overnight and over southern half from I-72 south Saturday
morning. Lows tonight to range from upper 50s and lower 60s over IL
river valley to upper 60s southeast of I-70 where muggy conditions
linger through tonight. North winds to advect in cooler and less
humid air during the day Saturday as clouds decrease from nw to se
Saturday afternoon. Much cooler highs in the mid 70s Saturday as
1022 mb high pressure over the northern Rockies settles east into
the central plains. This high pressure will settle over IL and
southern great lakes Sunday and keep cooler and less humid air in
place. Lows Saturday and Sunday night in low to mid 50s with a few
upper 40s over a few spots from I-74 ne. A fair amount of sunshine
Sunday with highs in the mid to upper 70s and comfortable dewpoints
in the low to mid 50s. Another nice day in store Monday as high
pressure settles into New England and clouds increase from the west
over IL ahead of next weather system. Highs in the upper 70s central
IL and near 80F south of I-70.
Unsettled weather pattern taking shape from Monday night through
Thu. Weather system spread qpf into IL from west to east during
Monday night into Tue and models have trended faster with this
feature so have increased pops. A stronger weather system arriving
Wed/Thu time frame as surface low pressure deepens ne from the
southern plains into the great lakes. Expect increased chances of
showers and a few thunderstorms. Then much cooler temperatures
arrive by next Friday and Friday night.
&&
.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
ISSUED AT 605 AM CDT FRI SEP 5 2014
A cold front over east central Iowa will push into our area early
this afternoon and bring the threat for scattered showers and
thunderstorms to central through east central Illinois into early
this evening. Other than some patchy fog early this morning which
may produce a brief period of MVFR vsbys, VFR conditions are expected
into this evening. Forecast soundings and time height cross sections
indicate that as the cooler air arrives later this evening, it may be
accompanied by some MVFR or possibly IFR cigs in the 08z-12z time
frame. Not seeing a lot of evidence of widespread MVFR or lower cigs
behind the cold front at this time, so will only introduce a scattered
cloud below 1000 feet late in the period with a prevailing cig above
that at 3500-4000 feet. Coverage of storms this afternoon near the
front scattered at best with the latest HRRR model suggesting areas
along and southeast of a Danville to Lincoln to Jacksonville line
having a better chance for seeing convection into early this evening.
For this reason, will continue with the tempo groups at KCMI, KDEC
and KSPI, with VCTS further north at KBMI and KPIA where it appears
coverage of storms will be less.
It appears there may be a break in the convection early this evening
with a round of showers moving in late tonight into Saturday morning
as a weak area of low pressure drifts east along the slow moving cold
front, which by this time, should be south of our area. Will carry
a VCSH for later this evening across most of our area and keep an eye
on the lowering cigs. Surface winds ahead of the front will be out
of the southwest at 10 to 15 kts, then become westerly along the
boundary, and with the FROPA, winds should shift to a northwest
to north direction by late afternoon and early evening with speeds
running from 8 to 13 kts.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HJS
SHORT TERM...SMITH
LONG TERM...07
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
654 AM CDT FRI SEP 5 2014
.DISCUSSION...
325 AM CDT
THE EMPHASIS OF THE FORECAST WAS SPENT ON THE FIRST 24 HOURS
WHICH PRESENT THUNDERSTORMS IN THE REGION TODAY...INCLUDING THE
POTENTIAL FOR SOME SEVERE STORMS THIS AFTERNOON...AND THEN RAIN
CHANCES THROUGH TONIGHT.
TODAY...
A VERY MILD...MUGGY...AND EVEN BREEZY EARLY MORNING ACROSS THE AREA
WITH SOME PARTS OF CHICAGO AT 80 DEGREES AS OF 3 AM. AREA DEW POINTS
ARE IN THE MID 70S...MATCHING THAT OF THE GULF SEABOARD THIS
MORNING. THIS SURFACE WARM SECTOR IN PLACE IS ASSOCIATED WITH A
1000MB LOW PRESSURE DEPARTING NORTHEASTWARD WITH ITS PARENT UPPER
TROUGH ACROSS ONTARIO THIS MORNING. THE ELONGATED SYSTEM COLD
FRONT WILL OOZE SOUTHEASTWARD REACHING NORTH CENTRAL IL DURING
MID-MORNING AND THE CHICAGO AREA AROUND NOONTIME...WHILE CLEARING
THE SOUTHEAST FORECAST AREA BY EARLY THIS EVENING.
WHILE THE REGIONAL RADAR THIS MORNING DOES SHOW A DECENT AMOUNT OF
CONVECTION IN IA AND EASTERN NE...MUCH OF THAT IS POST FRONTAL. ANY
SHOWERS OR STORMS BEFORE NOON WOULD LIKELY BE DUE TO A SUBTLE
MOISTENING IN THE VERY UNSTABLE LAYER ALOFT...WHICH THERE IS A
LITTLE BIT OF ON IR/11-3.9 MICRON SATELLITE IMAGERY. THIS TYPE OF
FORCING WOULD INDICATE ONLY ISOLATED IN COVERAGE IF DEVELOPMENT
WERE TO OCCUR.
WITH SURFACE HEATING AND ADVECTION OF EVEN HIGHER 0-1KM MIXING
RATIOS AHEAD OF THE FRONT DURING THE AFTERNOON...ADAPTED MODEL
SOUNDINGS LEAD TO FAIRLY HIGH CONFIDENCE THAT THE CAP WILL BE
BREACHED WITH SCATTERED STORMS ALONG THE COLD FRONT. DEPENDING ON
THE DEGREE OF HEATING...THIS COULD OCCUR ALREADY BY 12-2 PM. THIS
IS MOST FAVORED ALONG AND EAST OF INTERSTATE 55. LOOKING AT
HIGH-RES CONVECTIVE MODELS IN AN ENSEMBLE APPROACH /SPC
SSEO/...THERE ARE GOOD NEIGHBORHOOD VALUES OF HIGHER UPDRAFT SPEED
SUPPORTED BY HIGH INSTABILITY WITH MLCAPE IN EXCESS OF 3000 J/KG.
WITH LAGGING UPPER/MID-LEVEL FLOW TO THE FRONT...INSTABILITY WILL
BE THE DRIVER OF THESE STORMS AND THEIR INITIAL EVOLUTION.
EXPECTING A MODE THUS OF SOMEWHAT SLOW-MOVING CELLS OR MULTI-
CELLS WHICH SHOULD EVOLVE SOUTHEASTWARD THROUGH LATE
AFTERNOON/EARLY EVENING. A SCATTERED LARGE HAIL AND LOCALIZED
FLASH FLOODING THREAT WILL EXIST...AND WITH ANY MULTI-CELLS AN
ISOLATED SEVERE WIND THREAT...WITH THE LATTER LOOKING BETTER
FURTHER EAST AS STORM ORGANIZATION IS MORE FAVORED.
TONIGHT...
WHILE THE SURFACE FRONT WILL HAVE CLEARED THE FORECAST AREA BY OR
DURING EARLY EVENING...A SECOND STRONG UPPER SHORT WAVE ACROSS CO
EARLY THIS MORNING WILL TRACK NORTHEASTWARD ALONG THE 700-500MB
BAROCLINIC ZONE. THIS HAS BEEN CONSISTENTLY FORECAST IN THE REGION MY
MODELS FOR DAYS AND NOW OBSERVATIONAL SATELLITE TRENDS ARE
SUPPORTING THIS. THIS IS AN EARLY SIGN OF THE COOL SEASON...AS THIS
TYPE OF FORCING BEGINS TO SHOW UP MORE AND WILL EVENTUALLY
REPLACE THE VERTICAL INSTABILITY THAT WE ARE LOOK AT TODAY. BUT
NO NEED TO RUSH INTO THAT! SO BACK TO TONIGHT...A VERTICAL
FRONTAL CIRCULATION IS FORECAST WHICH WITH MOISTURE TRANSPORT AND
SATURATION IN THE MID-LEVELS SHOULD AT LEAST ALLOW LIKELY RAIN
IN THE REGION. THERE IS UNCERTAINTY ON HOW FAR NORTH RAIN THIS WILL
BE. ITS CERTAINLY PLAUSIBLE THAT EVEN THE NORTHERN CWA GETS INTO
THIS...WITH ROCKFORD AND CHICAGO HAVING A FEW HOUR PERIOD OF LIGHT
RAIN THIS EVENING INTO EARLY OVERNIGHT. ELEVATED INSTABILITY WILL
BE SLOW TO DEPART IN THE SOUTHERN FORECAST AREA SO CONTINUE
THUNDER CHANCES WITH MORE OF A MODERATE RAIN THERE. ADDITIONAL
RAINFALL AMOUNTS TONIGHT OF OVER ONE HALF INCH ARE FAVORED UNDER
ANY MORE SUSTAINED RAIN CORRIDORS THAT SET UP.
THIS WEEKEND...
NO REAL CHANGES MADE TO THIS PORTION OF THE FORECAST. LINGERING
ANAFRONTAL CLOUDS COULD CONTINUE SATURDAY MORNING BUT A CLEAR SKY IS
EXPECTED FOR THE REST OF THE WEEKEND. AFTERNOON TEMPERATURES IN
THE LOWER TO MID 70S...ABOUT 5 TO 7 DEGREES BELOW NORMAL...ARE
FORECAST. SURFACE WINDS SHOULD BECOME CALM EACH LATE EVENING AND
WITH DRIER AIR ADVECTION CONTINUING...WE UNDERCUT A MODEL FORECAST
BLEND FOR LOWS. SHOULD SEE OUTLYING AREAS REALIZE LOWS IN THE
UPPER 40S WITH COOL SPOTS POSSIBLY MID 40S.
NEXT WEEK...
CONTINUED QUASI-ZONAL UPPER FLOW ACROSS THE NORTHERN U.S. AT THE
FAR SOUTHERN BASE OF A COLD CANADIAN TROUGH IS FORECAST NEXT WEEK.
RETURN LOW-LEVEL LOW RESUMES EARLY IN THE WORKWEEK...BUT
MOISTENING LOOKS SLOW. GIVEN THAT AND THE FACT ANY FORCING
MECHANISMS LOOK TO BE LOW AMPLITUDE...SPREAD POPS IN SLOWER THAN
GUIDANCE MONDAY NIGHT-TUESDAY NIGHT. NOT SURPRISING TO SEE A LARGE
MODEL SPREAD IN SPECIFICS DURING THE MIDDLE OF NEXT WEEK...BUT
RIGHT NOW SOMETIME IN THE WEDNESDAY-THURSDAY PERIOD A STRONGER
SHORT WAVE TROUGH IS FORECAST TO PASS...WHICH CONCEIVABLY WOULD
BRING THE GREATER RAIN CHANCES TO THE REGION.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* TIMING/COVERAGE OF TSRA TODAY.
* WIND SHIFT FROM SW TO NW WITH COLD FRONT THIS AFTN.
* POTENTIAL FOR MVFR CIGS BEHIND COLD FRONT AND WITH PCPN THIS
AFTN/TONIGHT.
RATZER
//DISCUSSION...UPDATED 12Z...
COLD FRONT STRETCHES FROM EAST CENTRAL WI TO EASTERN IA THIS
MORNING. ISOLATED SHRA/TSRA POSSIBLE IN WARM/MOIST SOUTHWEST FLOW
AHEAD OF THE FRONT THIS MORNING...THOUGH LITTLE TO FOCUS
WIDESPREAD DEVELOPMENT EXPECTED UNTIL SURFACE COLD FRONT
APPROACHES AND TIMING OF COLD FROPA STILL APPEARS TO BE AROUND
15Z FOR KRFD AND 19-20Z FOR KORD/KMDW. THE GREATEST POTENTIAL FOR
TSRA WILL BE THIS AFTERNOON ALONG/AHEAD OF THE FRONT...WITH HIGH-
RES MODEL GUIDANCE INDICATING TSRA INITIATION NEAR OR SOUTHEAST OF
CHICAGO. TSRA THREAT SHOULD MOVE SOUTHEAST OF TERMINALS BY LATE
AFTERNOON AS THE FRONT CONTINUES TO PUSH SOUTHEAST. MVFR CIGS
POSSIBLE IN SHRA/TSRA...AND ALSO FOR A PERIOD BEHIND THE FRONT
THIS AFTERNOON. SHOWERS/RAIN EXPECTED TO REDEVELOP ACROSS THE
TERMINALS THIS EVENING WITH FURTHER MVFR CIG POTENTIAL AS AN
UPPER DISTURBANCE PROPAGATES ACROSS THE AREA. EXPECTATION IS FOR
CIGS TO BE IN 2000-3000 FT RANGE. DRIER AIR FINALLY MOVES IN EARLY
SATURDAY MORNING WITH VFR CONDITIONS.
SOUTHWEST WINDS AROUND 10 KT THIS MORNING AHEAD OF THE FRONT WILL
SHIFT MORE WEST-SOUTHWEST WITH TIME...THEN NORTHWEST BEHIND THE
FRONT. SOME GUIDANCE INDICATES WINDS MAY BECOME MORE NORTH OR EVEN
NORTH-NORTHEAST BRIEFLY THIS AFTERNOON...BUT LIKELY TO HOLD OFF
UNTIL LATE TONIGHT/SATURDAY.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* MEDIUM IN TSRA/MVFR CIGS.
* HIGH FOR WINDS AND OTHER FORECAST ELEMENTS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT THROUGH MONDAY...VFR. SLGT CHC TSRA MONDAY NIGHT.
TUESDAY AND WEDNESDAY...CHC OF PERIODIC TSRA. MVFR CIGS PSBL.
THURSDAY...CHC OF SHOWERS. MVFR CIGS PSBL.
RATZER
&&
.MARINE...
314 AM CDT
LOW PRESSURE WAS NORTH OF LAKE SUPERIOR EARLY THIS MORNING...WITH A
COLD FRONT TRAILING SOUTHWEST ACROSS WISCONSIN AND EASTERN IOWA.
THIS LOW WILL TRACK TO THE NORTHEAST WHILE CONTINUING TO DEEPEN
TODAY WHILE THE FRONT PUSHES SOUTHEAST ACROSS THE LAKE THROUGH THIS
AFTERNOON. SURFACE PRESSURE FALLS AND A RELATIVELY TIGHT PRESSURE
GRADIENT AHEAD OF THE FRONT AND ASSOCIATED WITH THE DEEPENING LOW
HAS LED TO SOUTH-SOUTHWEST WINDS IN THE 25-30 KT RANGE OVERNIGHT.
WINDS SHOULD GRADUALLY EASE INTO THE 15-25 KT RANGE AS THE GRADIENT
WEAKENS IN PROXIMITY TO THE COLD FRONTAL TROUGH LATER THIS MORNING
AND THIS AFTERNOON...VEERING TO THE NORTHWEST AND EVENTUALLY NORTH
BEHIND THE FRONT TONIGHT. SURFACE HIGH PRESSURE WILL THEN BUILD
SOUTHEAST ACROSS THE PLAINS...AND EAST ACROSS THE SOUTHERN GREAT
LAKES TONIGHT AND SATURDAY WHILE A SECOND WEAK COLD FRONT SETTLES
ACROSS THE NORTHERN LAKES. NORTH-NORTHWEST WINDS ARE EXPECTED TO
REMAIN IN THE 15-20 KT RANGE WITH A FEW GUSTS TO 25 KT POSSIBLE INTO
EARLY SATURDAY AS COOL AIR BUILDS IN WITH THE HIGH...THEN SLACKEN
SATURDAY NIGHT AND SUNDAY AS THE HIGH MOVES EAST ACROSS THE LAKES.
BY MONDAY THE HIGH WILL SHIFT OVER THE ST LAWRENCE VALLEY...WHILE
LOW PRESSURE DEVELOPS ACROSS THE NORTHERN PLAINS. THIS WILL ALLOW
WINDS TO SHIFT BACK TO THE SOUTH EARLY NEXT WEEK...WITH THE PLAINS
LOW EVENTUALLY APPROACHING THE GREAT LAKES MID-WEEK.
FOR THE ILLINOIS/NORTHWEST INDIANA NEARSHORE WATERS...SOME GUSTS
NEAR 30 KT NOTED FROM HIGH-MOUNTED WIND MEASURING EQUIPMENT THIS
MORNING BUT WITH RELATIVELY LOW WAVES IN OFFSHORE FLOW. NORTHERLY
FETCH LATER TONIGHT AND SATURDAY LOOKS TO PRODUCE MARGINAL SMALL
CRAFT ADVISORY CONDITIONS.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
608 AM CDT Fri Sep 5 2014
.SHORT TERM...(Today)
ISSUED AT 328 AM CDT FRI SEP 5 2014
Cold front beginning to edge into east central Iowa early this
morning with most models pushing the boundary across our area during
the afternoon and early evening hours. One more hot and humid day
ahead of the cold front with temperatures ranging from the upper
80s far northwest to the lower 90s east central through southeast
Illinois. Forecast soundings showing the warm layer extending from
850-700 mb will gradually erode with time today which should allow
better coverage of convection along the frontal boundary despite
rather weak convergence. However, most models depict some robust
CAPES this afternoon with 3500-4500 J/KG forecast over central thru
east central Illinois. 0-6km bulk shear not very impressive until
you get behind the cold front, otherwise, most models indicate bulk
shear values of 15-20 kts in the warm section just ahead of the
front. Precipitable water values of around 2 inches still forecast
this afternoon so any storms that organize will produce torrential
rainfall in a short period of time, in addition to the possibility
for an isolated strong wind gust/wet microburst. Most of the
convective allowing models suggest the stronger convection will
begin to push into Indiana by late this afternoon or early this
evening and then begin to weaken.
&&
.LONG TERM...(Tonight through Friday)
ISSUED AT 328 AM CDT FRI SEP 5 2014
Cold front passes southeast of CWA this evening, while 00Z models
have trended slower with mid/upper level system/forcing tonight
into Saturday morning with showers and isolated thunderstorms likely
lingering overnight and over southern half from I-72 south Saturday
morning. Lows tonight to range from upper 50s and lower 60s over IL
river valley to upper 60s southeast of I-70 where muggy conditions
linger through tonight. North winds to advect in cooler and less
humid air during the day Saturday as clouds decrease from nw to se
Saturday afternoon. Much cooler highs in the mid 70s Saturday as
1022 mb high pressure over the northern Rockies settles east into
the central plains. This high pressure will settle over IL and
southern great lakes Sunday and keep cooler and less humid air in
place. Lows Saturday and Sunday night in low to mid 50s with a few
upper 40s over a few spots from I-74 ne. A fair amount of sunshine
Sunday with highs in the mid to upper 70s and comfortable dewpoints
in the low to mid 50s. Another nice day in store Monday as high
pressure settles into New England and clouds increase from the west
over IL ahead of next weather system. Highs in the upper 70s central
IL and near 80F south of I-70.
Unsettled weather pattern taking shape from Monday night through
Thu. Weather system spread qpf into IL from west to east during
Monday night into Tue and models have trended faster with this
feature so have increased pops. A stronger weather system arriving
Wed/Thu time frame as surface low pressure deepens ne from the
southern plains into the great lakes. Expect increased chances of
showers and a few thunderstorms. Then much cooler temperatures
arrive by next Friday and Friday night.
&&
.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
ISSUED AT 605 AM CDT FRI SEP 5 2014
A cold front over east central Iowa will push into our area early
this afternoon and bring the threat for scattered showers and
thunderstorms to central through east central Illinois into early
this evening. Other than some patchy fog early this morning which
may produce a brief period of MVFR vsbys, VFR conditions are expected
into this evening. Forecast soundings and time height cross sections
indicate that as the cooler air arrives later this evening, it may be
accompanied by some MVFR or possibly IFR cigs in the 08z-12z time
frame. Not seeing a lot of evidence of widespread MVFR or lower cigs
behind the cold front at this time, so will only introduce a scattered
cloud below 1000 feet late in the period with a prevailing cig above
that at 3500-4000 feet. Coverage of storms this afternoon near the
front scattered at best with the latest HRRR model suggesting areas
along and southeast of a Danville to Lincoln to Jacksonville line
having a better chance for seeing convection into early this evening.
For this reason, will continue with the tempo groups at KCMI, KDEC
and KSPI, with VCTS further north at KBMI and KPIA where it appears
coverage of storms will be less.
It appears there may be a break in the convection early this evening
with a round of showers moving in late tonight into Saturday morning
as a weak area of low pressure drifts east along the slow moving cold
front, which by this time, should be south of our area. Will carry
a VCSH for later this evening across most of our area and keep an eye
on the lowering cigs. Surface winds ahead of the front will be out
of the southwest at 10 to 15 kts, then become westerly along the
boundary, and with the FROPA, winds should shift to a northwest
to north direction by late afternoon and early evening with speeds
running from 8 to 13 kts.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SMITH
LONG TERM...07
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1015 AM EDT FRI SEP 5 2014
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 324 AM EDT FRI SEP 5 2014
VERY WARM HUMID CONDITIONS TODAY WILL COME TO AN ABRUPT END AS A
COLD FRONT TRACKS THROUGH THE REGION WITH SHOWERS AND THUNDERSTORMS
TONIGHT AND SATURDAY. HIGH PRESSURE WILL BUILD IN BEGINNING SATURDAY
NIGHT WITH DRY AND MUCH COOLER WEATHER INTO EARLY NEXT WEEK.
THUNDERSTORM CHANCES WILL RETURN TUESDAY AND CONTINUE THROUGH MUCH
OF NEXT WEEK AS A COLD FRONT MOVES THROUGH THE GREAT LAKES AND OHIO
VALLEY.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 955 AM EDT FRI SEP 5 2014
.UPDATE...CURRENT FORECAST IS ON TRACK AND ONLY MINOR CHANGES MADE
WITH THIS UPDATE...MAINLY TO RAISE POPS SLIGHTLY OVER FAR NORTHERN
SECTIONS AS SHOWERS AND THUNDERSTORMS WERE ALREADY OVER NORTHEAST
ILLINOIS WHICH MAY BRUSH FAR NORTHERN AREAS IN A FEW HOURS.
PORTION OF PREVIOUS NEAR TERM DISCUSSION FOLLOWS...
MOST CONVECTION HAS REMAINED WELL NORTH/NORTHWEST OF THE FORECAST
AREA ALONG A COLD FRONT. MOST INTENSE STORMS ACROSS THE NORTHERN
GREAT LAKES THIS MORNING IN VICINITY OF A STRONGER SURFACE WAVE AND
A SHARPENING UPPER TROUGH. THE UPPER RIDGE WILL BUCKLE IN RESPONSE
TO THE AMPLIFYING UPPER TROUGH OVER THE UPPER MISSISSIPPI VALLEY...
ENABLING THE FRONTAL BOUNDARY TO SAG INTO THE NORTHERN FORECAST AREA
BY THIS EVENING.
AHEAD OF THE FRONT...ABUNDANT SUNSHINE AND SOUTHWEST FLOW WILL
PROVIDE FOR ANOTHER VERY WARM HUMID DAY FOR CENTRAL INDIANA. MID
LEVEL HEIGHTS WILL BEGIN TO FALL BY THE AFTERNOON AS THE FRONT
APPROACHES FROM THE NORTH AND COMBINED WITH VERY WEAK UPPER FORCING
AND A STRONGLY UNSTABLE AIRMASS...WILL INTRODUCE LOW CHANCE POPS
GRADUALLY INCREASING FROM THE NORTHWEST INTO THE EVENING. BOTH THE
WRF AND HRRR THIS MORNING APPEAR OVERDONE WITH RESPECT TO CONVECTIVE
DEVELOPMENT IN THE AFTERNOON...BUT ISOLATED STORMS CERTAINLY CANNOT
BE RULED OUT WITH THE PARAMETERS ABOVE. A LINE OF MORE ROBUST
CONVECTION IS EXPECTED TO DEVELOP THIS AFTERNOON IN THE VICINITY OF
THE FRONT OVER THE LOWER GREAT LAKES. THESE STORMS WILL BE
APPROACHING THE FORECAST AREA FROM THE NORTHWEST BY 00Z.
TEMPS...WITH 850MB TEMPS AT 20-21C AND A SOUTHWEST FLOW THIS
AFTERNOON...HAVE TRENDED TOWARDS THE WARMER MAVMOS FOR HIGHS IN THE
UPPER 80S AND LOWER 90S. MAX HEAT INDICES OF 95 TO 100 DEGREES THIS
AFTERNOON ARE EXPECTED AS WELL AND WILL HIGHLIGHT IN THE HWO.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 324 AM EDT FRI SEP 5 2014
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES THROUGH LATE SATURDAY AS
THE FRONT MOVES THROUGH THE REGION. 00Z MODEL GUIDANCE HAS GENERALLY
SLOWED THE PASSAGE OF THE BOUNDARY WITH PRECIP CHANCES LINGERING
OVER MUCH OF THE SOUTHERN HALF OF THE FORECAST AREA FOR A GOOD
PORTION OF SATURDAY.
FIRST ISSUE IS WITH EXPECTED CONVECTION MOVING INTO THE FORECAST
AREA FROM THE NORTHWEST THIS EVENING. WHILE STRONGER MID/UPPER LEVEL
FORCING AND STRONGER BL SHEAR WILL REMAIN WELL NORTH OF THE
REGION...PRESENCE OF CONVECTION MOVING INTO A STRONGLY UNSTABLE
AIRMASS WITH HIGH PRECIP WATER VALUES SHOULD BE ABLE TO COMPENSATE
FOR STORM INTENSITY MAINTENANCE INTO THE FORECAST AREA THIS EVENING.
POTENTIAL FOR A FEW OF THESE STORMS TO BE SEVERE...ESPECIALLY IF
CONVECTION CAN LAY DOWN A COLD POOL AND PROVIDE FOR AN ENHANCED
DAMAGING WIND THREAT FOR A SHORT PERIOD OF TIME. AS INSTABILITY
WANES AND THE STORMS MOVE AWAY FROM THE LIMITED BL SHEAR...SHOULD
SEE STORMS WEAKEN AND DIMINISH IN COVERAGE BY LATE EVENING SOUTH OF
I-70. WILL CARRY LIKELY POPS NORTH OF I-70 WITH LOWER POPS FURTHER
SOUTH.
THE FRONT WILL CONTINUE ITS SLOW PROGRESS SOUTH THROUGH THE FORECAST
AREA SATURDAY. MID LEVEL DEFORMATION AXIS PASSING THROUGH THE LOWER
GREAT LAKES WITH THE UPPER TROUGH WILL LINGER PRECIP CHANCES OVER
THE REGION...BUT WITH AN ABUNDANCE OF CLOUDS AND LIMITED
INSTABILITY...HARD TO JUSTIFY MUCH MORE THAN AN ISOLATED THUNDER
THREAT WITH SHOWERS. SHOWERS WILL GRADUALLY SHIFT INTO SOUTHERN
COUNTIES DURING THE AFTERNOON AS DRIER AIR ADVECTS IN FROM THE
NORTH...WITH PRECIP SOUTH OF THE REGION BY SATURDAY EVENING AS THE
FRONT MOVES INTO THE TENNESSEE VALLEY.
REMAINDER OF THE SHORT TERM WILL BE QUIET AS BROAD HIGH PRESSURE
TAKES OVER ACROSS THE MIDWEST AND OHIO VALLEY. A MUCH COOLER DRIER
AIRMASS WILL BRING A REFRESHING CHANGE FOR THE SECOND HALF OF THE
WEEKEND AND INTO EARLY NEXT WEEK.
TEMPS...MAVMOS APPEARED REASONABLE THROUGHOUT THE SHORT TERM AS
HIGHS FALL BACK INTO THE 70S BOTH SATURDAY AND SUNDAY. ONE LAST
HUMID NIGHT FOR TONIGHT WITH MUCH MORE COMFORTABLE TEMPS FOR
SATURDAY/SUNDAY NIGHTS INTO THE LOWER AND MIDDLE 50S...WITH MAYBE
EVEN A FEW RURAL LOCATIONS FALLING INTO THE UPPER 40S.
&&
.LONG TERM /MONDAY THROUGH THURSDAY NIGHT/...
ISSUED AT 342 AM EDT FRI SEP 5 2014
DRY CONDITIONS CAN BE EXPECTED ON MONDAY WITH ZONAL FLOW ALOFT AND
WEAK HIGH PRESSURE STILL AT THE SURFACE. HOWEVER...THE PATTERN WILL
QUICKLY SHIFT BY TUESDAY AS A BROAD UPPER TROUGH ENTERS THE AREA.
WIDESPREAD SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS CENTRAL
INDIANA AS EARLY AS TUESDAY MORNING...WITH INCREASING CHANCES
THROUGH THE COURSE OF THE EXTENDED PERIOD AS A COLD FRONT TRACKS
ACROSS THE AREA ON WEDNESDAY NIGHT/THURSDAY. PRECIP CHANCES WILL
TAPER OFF TOWARD THE END OF THE PERIOD...BUT WILL KEEP MENTION OF
SHOWERS AND THUNDERSTORMS IN THE FORECAST THROUGH THURSDAY NIGHT TO
ACCOUNT FOR PASSAGE OF UPPER LOW. TEMPS WILL CONTINUE TO DROP WELL
BELOW NORMAL THROUGH THE COURSE OF THE EXTENDED PERIOD WITH HIGH
TEMPS ONLY IN THE UPPER 60S/LOW 70S BY FRIDAY.
&&
.AVIATION /DISCUSSION FOR THE 05/1500Z TAF ISSUANCE/...
ISSUED AT 1015 AM EDT FRI SEP 5 2014
FOR THE UPDATE...MOVED UP THE TIMING OF VCTS AT KIND AND ADDED A
TEMPO GROUP FOR THUNDERSTORMS AT KLAF DUE TO LINE OF SHOWERS AND
STORMS ALREADY OVER CENTRAL/NORTHEASTERN ILLINOIS MOVING EAST INTO
THE AREA. TIMING TOOL BRINGS THE LINE INTO KLAF AROUND 16Z.
SOUTHWARD EXTENT OF THE LINE WILL DETERMINE WHETHER OR NOT IT WILL
IMPACT OTHER SITES AND THINK KIND IS CLOSE ENOUGH TO BUMP UP THE
VCTS BUT NOT CONFIDENT ENOUGH TO ADD TEMPO THERE AT THIS TIME. STILL
EXPECTING ANOTHER LINE LATER ASSOCIATED WITH THE COLD FRONT.
PREVIOUS DISCUSSION FOLLOWS...
WIDESPREAD SHOWERS AND THUNDERSTORMS WILL SPREAD OVER TAF SITES
THIS AFTERNOON AS A COLD FRONT ENTERS THE AREA. ACTIVITY WILL
START ENTERING KLAF BETWEEN FRI 18-21Z...MOVING SOUTHEAST THROUGH
THE REMAINING SITES. CONVECTION WILL INTENSIFY DURING THE SAT
00Z-06Z TIME FRAME. CONDITIONS WILL GENERALLY BE AT VFR CATEGORY
EXCEPT DURING ANY STRONG STORMS THAT COULD RESULT IN BRIEF MVFR
CONDITIONS. IT ISN/T UNTIL AFTER SAT 06Z THAT CONDITIONS WILL
QUICKLY PLUMMET TO MVFR OR WORSE AS CEILINGS LOWER FURTHER.
WINDS WILL BE SOUTHWESTERLY INTO THE EVENING HOURS...AND A LITTLE
BREEZY WITH SUSTAINED SPEEDS OF 10 TO 12 KTS. WINDS WILL VEER TO
THE NORTHWEST TONIGHT AFTER FRONTAL PASSAGE...SUSTAINED AT
8 TO 10 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN/JH
SHORT TERM...RYAN
LONG TERM....TDUD
AVIATION...TDUD/CP
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
955 AM EDT FRI SEP 5 2014
.UPDATE...
NEAR TERM FOR THE REST OF TODAY HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 324 AM EDT FRI SEP 5 2014
VERY WARM HUMID CONDITIONS TODAY WILL COME TO AN ABRUPT END AS A
COLD FRONT TRACKS THROUGH THE REGION WITH SHOWERS AND THUNDERSTORMS
TONIGHT AND SATURDAY. HIGH PRESSURE WILL BUILD IN BEGINNING SATURDAY
NIGHT WITH DRY AND MUCH COOLER WEATHER INTO EARLY NEXT WEEK.
THUNDERSTORM CHANCES WILL RETURN TUESDAY AND CONTINUE THROUGH MUCH
OF NEXT WEEK AS A COLD FRONT MOVES THROUGH THE GREAT LAKES AND OHIO
VALLEY.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 955 AM EDT FRI SEP 5 2014
.UPDATE...CURRENT FORECAST IS ON TRACK AND ONLY MINOR CHANGES MADE
WITH THIS UPDATE...MAINLY TO RAISE POPS SLIGHTLY OVER FAR NORTHERN
SECTIONS AS SHOWERS AND THUNDERSTORMS WERE ALREADY OVER NORTHEAST
ILLINOIS WHICH MAY BRUSH FAR NORTHERN AREAS IN A FEW HOURS.
PORTION OF PREVIOUS NEAR TERM DISCUSSION FOLLOWS...
MOST CONVECTION HAS REMAINED WELL NORTH/NORTHWEST OF THE FORECAST
AREA ALONG A COLD FRONT. MOST INTENSE STORMS ACROSS THE NORTHERN
GREAT LAKES THIS MORNING IN VICINITY OF A STRONGER SURFACE WAVE AND
A SHARPENING UPPER TROUGH. THE UPPER RIDGE WILL BUCKLE IN RESPONSE
TO THE AMPLIFYING UPPER TROUGH OVER THE UPPER MISSISSIPPI VALLEY...
ENABLING THE FRONTAL BOUNDARY TO SAG INTO THE NORTHERN FORECAST AREA
BY THIS EVENING.
AHEAD OF THE FRONT...ABUNDANT SUNSHINE AND SOUTHWEST FLOW WILL
PROVIDE FOR ANOTHER VERY WARM HUMID DAY FOR CENTRAL INDIANA. MID
LEVEL HEIGHTS WILL BEGIN TO FALL BY THE AFTERNOON AS THE FRONT
APPROACHES FROM THE NORTH AND COMBINED WITH VERY WEAK UPPER FORCING
AND A STRONGLY UNSTABLE AIRMASS...WILL INTRODUCE LOW CHANCE POPS
GRADUALLY INCREASING FROM THE NORTHWEST INTO THE EVENING. BOTH THE
WRF AND HRRR THIS MORNING APPEAR OVERDONE WITH RESPECT TO CONVECTIVE
DEVELOPMENT IN THE AFTERNOON...BUT ISOLATED STORMS CERTAINLY CANNOT
BE RULED OUT WITH THE PARAMETERS ABOVE. A LINE OF MORE ROBUST
CONVECTION IS EXPECTED TO DEVELOP THIS AFTERNOON IN THE VICINITY OF
THE FRONT OVER THE LOWER GREAT LAKES. THESE STORMS WILL BE
APPROACHING THE FORECAST AREA FROM THE NORTHWEST BY 00Z.
TEMPS...WITH 850MB TEMPS AT 20-21C AND A SOUTHWEST FLOW THIS
AFTERNOON...HAVE TRENDED TOWARDS THE WARMER MAVMOS FOR HIGHS IN THE
UPPER 80S AND LOWER 90S. MAX HEAT INDICES OF 95 TO 100 DEGREES THIS
AFTERNOON ARE EXPECTED AS WELL AND WILL HIGHLIGHT IN THE HWO.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 324 AM EDT FRI SEP 5 2014
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES THROUGH LATE SATURDAY AS
THE FRONT MOVES THROUGH THE REGION. 00Z MODEL GUIDANCE HAS GENERALLY
SLOWED THE PASSAGE OF THE BOUNDARY WITH PRECIP CHANCES LINGERING
OVER MUCH OF THE SOUTHERN HALF OF THE FORECAST AREA FOR A GOOD
PORTION OF SATURDAY.
FIRST ISSUE IS WITH EXPECTED CONVECTION MOVING INTO THE FORECAST
AREA FROM THE NORTHWEST THIS EVENING. WHILE STRONGER MID/UPPER LEVEL
FORCING AND STRONGER BL SHEAR WILL REMAIN WELL NORTH OF THE
REGION...PRESENCE OF CONVECTION MOVING INTO A STRONGLY UNSTABLE
AIRMASS WITH HIGH PRECIP WATER VALUES SHOULD BE ABLE TO COMPENSATE
FOR STORM INTENSITY MAINTENANCE INTO THE FORECAST AREA THIS EVENING.
POTENTIAL FOR A FEW OF THESE STORMS TO BE SEVERE...ESPECIALLY IF
CONVECTION CAN LAY DOWN A COLD POOL AND PROVIDE FOR AN ENHANCED
DAMAGING WIND THREAT FOR A SHORT PERIOD OF TIME. AS INSTABILITY
WANES AND THE STORMS MOVE AWAY FROM THE LIMITED BL SHEAR...SHOULD
SEE STORMS WEAKEN AND DIMINISH IN COVERAGE BY LATE EVENING SOUTH OF
I-70. WILL CARRY LIKELY POPS NORTH OF I-70 WITH LOWER POPS FURTHER
SOUTH.
THE FRONT WILL CONTINUE ITS SLOW PROGRESS SOUTH THROUGH THE FORECAST
AREA SATURDAY. MID LEVEL DEFORMATION AXIS PASSING THROUGH THE LOWER
GREAT LAKES WITH THE UPPER TROUGH WILL LINGER PRECIP CHANCES OVER
THE REGION...BUT WITH AN ABUNDANCE OF CLOUDS AND LIMITED
INSTABILITY...HARD TO JUSTIFY MUCH MORE THAN AN ISOLATED THUNDER
THREAT WITH SHOWERS. SHOWERS WILL GRADUALLY SHIFT INTO SOUTHERN
COUNTIES DURING THE AFTERNOON AS DRIER AIR ADVECTS IN FROM THE
NORTH...WITH PRECIP SOUTH OF THE REGION BY SATURDAY EVENING AS THE
FRONT MOVES INTO THE TENNESSEE VALLEY.
REMAINDER OF THE SHORT TERM WILL BE QUIET AS BROAD HIGH PRESSURE
TAKES OVER ACROSS THE MIDWEST AND OHIO VALLEY. A MUCH COOLER DRIER
AIRMASS WILL BRING A REFRESHING CHANGE FOR THE SECOND HALF OF THE
WEEKEND AND INTO EARLY NEXT WEEK.
TEMPS...MAVMOS APPEARED REASONABLE THROUGHOUT THE SHORT TERM AS
HIGHS FALL BACK INTO THE 70S BOTH SATURDAY AND SUNDAY. ONE LAST
HUMID NIGHT FOR TONIGHT WITH MUCH MORE COMFORTABLE TEMPS FOR
SATURDAY/SUNDAY NIGHTS INTO THE LOWER AND MIDDLE 50S...WITH MAYBE
EVEN A FEW RURAL LOCATIONS FALLING INTO THE UPPER 40S.
&&
.LONG TERM /MONDAY THROUGH THURSDAY NIGHT/...
ISSUED AT 342 AM EDT FRI SEP 5 2014
DRY CONDITIONS CAN BE EXPECTED ON MONDAY WITH ZONAL FLOW ALOFT AND
WEAK HIGH PRESSURE STILL AT THE SURFACE. HOWEVER...THE PATTERN WILL
QUICKLY SHIFT BY TUESDAY AS A BROAD UPPER TROUGH ENTERS THE AREA.
WIDESPREAD SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS CENTRAL
INDIANA AS EARLY AS TUESDAY MORNING...WITH INCREASING CHANCES
THROUGH THE COURSE OF THE EXTENDED PERIOD AS A COLD FRONT TRACKS
ACROSS THE AREA ON WEDNESDAY NIGHT/THURSDAY. PRECIP CHANCES WILL
TAPER OFF TOWARD THE END OF THE PERIOD...BUT WILL KEEP MENTION OF
SHOWERS AND THUNDERSTORMS IN THE FORECAST THROUGH THURSDAY NIGHT TO
ACCOUNT FOR PASSAGE OF UPPER LOW. TEMPS WILL CONTINUE TO DROP WELL
BELOW NORMAL THROUGH THE COURSE OF THE EXTENDED PERIOD WITH HIGH
TEMPS ONLY IN THE UPPER 60S/LOW 70S BY FRIDAY.
&&
.AVIATION /DISCUSSION FOR THE 05/1200Z TAF ISSUANCE/...
ISSUED AT 711 AM EDT FRI SEP 5 2014
WIDESPREAD SHOWERS AND THUNDERSTORMS WILL SPREAD OVER TAF SITES
THIS AFTERNOON AS A COLD FRONT ENTERS THE AREA. ACTIVITY WILL
START ENTERING KLAF BETWEEN FRI 18-21Z...MOVING SOUTHEAST THROUGH
THE REMAINING SITES. CONVECTION WILL INTENSIFY DURING THE SAT
00Z-06Z TIME FRAME. CONDITIONS WILL GENERALLY BE AT VFR CATEGORY
EXCEPT DURING ANY STRONG STORMS THAT COULD RESULT IN BRIEF MVFR
CONDITIONS. IT ISN/T UNTIL AFTER SAT 06Z THAT CONDITIONS WILL
QUICKLY PLUMMET TO MVFR OR WORSE AS CEILINGS LOWER FURTHER.
WINDS WILL BE SOUTHWESTERLY INTO THE EVENING HOURS...AND A LITTLE
BREEZY WITH SUSTAINED SPEEDS OF 10 TO 12 KTS. WINDS WILL VEER TO
THE NORTHWEST TONIGHT AFTER FRONTAL PASSAGE...SUSTAINED AT
8 TO 10 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN/JH
SHORT TERM...RYAN
LONG TERM....TDUD
AVIATION...TDUD
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
733 AM EDT FRI SEP 5 2014
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 324 AM EDT FRI SEP 5 2014
VERY WARM HUMID CONDITIONS TODAY WILL COME TO AN ABRUPT END AS A
COLD FRONT TRACKS THROUGH THE REGION WITH SHOWERS AND THUNDERSTORMS
TONIGHT AND SATURDAY. HIGH PRESSURE WILL BUILD IN BEGINNING SATURDAY
NIGHT WITH DRY AND MUCH COOLER WEATHER INTO EARLY NEXT WEEK.
THUNDERSTORM CHANCES WILL RETURN TUESDAY AND CONTINUE THROUGH MUCH
OF NEXT WEEK AS A COLD FRONT MOVES THROUGH THE GREAT LAKES AND OHIO
VALLEY.
&&
.NEAR TERM /TODAY/...
ISSUED AT 324 AM EDT FRI SEP 5 2014
JUST A FEW HIGH CLOUDS DRIFTING ACROSS CENTRAL INDIANA EARLY THIS
MORNING AS REGION RESIDES UNDER THE INFLUENCE OF THE RIDGING ALOFT
CENTERED OVER THE LOWER MISSISSIPPI VALLEY EAST THROUGH THE
SOUTHEAST STATES. 07Z TEMPS RANGED FROM THE UPPER 60S TO MID 70S.
CONVECTION HAS REMAINED WELL NORTH/NORTHWEST OF THE FORECAST AREA
ALONG A COLD FRONT. MOST INTENSE STORMS ACROSS THE NORTHERN GREAT
LAKES THIS MORNING IN VICINITY OF A STRONGER SURFACE WAVE AND A
SHARPENING UPPER TROUGH. THE UPPER RIDGE WILL BUCKLE IN RESPONSE TO
THE AMPLIFYING UPPER TROUGH OVER THE UPPER MISSISSIPPI VALLEY...
ENABLING THE FRONTAL BOUNDARY TO SAG INTO THE NORTHERN FORECAST AREA
BY THIS EVENING.
AHEAD OF THE FRONT...ABUNDANT SUNSHINE AND SOUTHWEST FLOW WILL
PROVIDE FOR ANOTHER VERY WARM HUMID DAY FOR CENTRAL INDIANA. MID
LEVEL HEIGHTS WILL BEGIN TO FALL BY THE AFTERNOON AS THE FRONT
APPROACHES FROM THE NORTH AND COMBINED WITH VERY WEAK UPPER FORCING
AND A STRONGLY UNSTABLE AIRMASS...WILL INTRODUCE LOW CHANCE POPS
GRADUALLY INCREASING FROM THE NORTHWEST INTO THE EVENING. BOTH THE
WRF AND HRRR THIS MORNING APPEAR OVERDONE WITH RESPECT TO CONVECTIVE
DEVELOPMENT IN THE AFTERNOON...BUT ISOLATED STORMS CERTAINLY CANNOT
BE RULED OUT WITH THE PARAMETERS ABOVE. A LINE OF MORE ROBUST
CONVECTION IS EXPECTED TO DEVELOP THIS AFTERNOON IN THE VICINITY OF
THE FRONT OVER THE LOWER GREAT LAKES. THESE STORMS WILL BE
APPROACHING THE FORECAST AREA FROM THE NORTHWEST BY 00Z.
TEMPS...WITH 850MB TEMPS AT 20-21C AND A SOUTHWEST FLOW THIS
AFTERNOON...HAVE TRENDED TOWARDS THE WARMER MAVMOS FOR HIGHS IN THE
UPPER 80S AND LOWER 90S. MAX HEAT INDICES OF 95 TO 100 DEGREES THIS
AFTERNOON ARE EXPECTED AS WELL AND WILL HIGHLIGHT IN THE HWO.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 324 AM EDT FRI SEP 5 2014
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES THROUGH LATE SATURDAY AS
THE FRONT MOVES THROUGH THE REGION. 00Z MODEL GUIDANCE HAS GENERALLY
SLOWED THE PASSAGE OF THE BOUNDARY WITH PRECIP CHANCES LINGERING
OVER MUCH OF THE SOUTHERN HALF OF THE FORECAST AREA FOR A GOOD
PORTION OF SATURDAY.
FIRST ISSUE IS WITH EXPECTED CONVECTION MOVING INTO THE FORECAST
AREA FROM THE NORTHWEST THIS EVENING. WHILE STRONGER MID/UPPER LEVEL
FORCING AND STRONGER BL SHEAR WILL REMAIN WELL NORTH OF THE
REGION...PRESENCE OF CONVECTION MOVING INTO A STRONGLY UNSTABLE
AIRMASS WITH HIGH PRECIP WATER VALUES SHOULD BE ABLE TO COMPENSATE
FOR STORM INTENSITY MAINTENANCE INTO THE FORECAST AREA THIS EVENING.
POTENTIAL FOR A FEW OF THESE STORMS TO BE SEVERE...ESPECIALLY IF
CONVECTION CAN LAY DOWN A COLD POOL AND PROVIDE FOR AN ENHANCED
DAMAGING WIND THREAT FOR A SHORT PERIOD OF TIME. AS INSTABILITY
WANES AND THE STORMS MOVE AWAY FROM THE LIMITED BL SHEAR...SHOULD
SEE STORMS WEAKEN AND DIMINISH IN COVERAGE BY LATE EVENING SOUTH OF
I-70. WILL CARRY LIKELY POPS NORTH OF I-70 WITH LOWER POPS FURTHER
SOUTH.
THE FRONT WILL CONTINUE ITS SLOW PROGRESS SOUTH THROUGH THE FORECAST
AREA SATURDAY. MID LEVEL DEFORMATION AXIS PASSING THROUGH THE LOWER
GREAT LAKES WITH THE UPPER TROUGH WILL LINGER PRECIP CHANCES OVER
THE REGION...BUT WITH AN ABUNDANCE OF CLOUDS AND LIMITED
INSTABILITY...HARD TO JUSTIFY MUCH MORE THAN AN ISOLATED THUNDER
THREAT WITH SHOWERS. SHOWERS WILL GRADUALLY SHIFT INTO SOUTHERN
COUNTIES DURING THE AFTERNOON AS DRIER AIR ADVECTS IN FROM THE
NORTH...WITH PRECIP SOUTH OF THE REGION BY SATURDAY EVENING AS THE
FRONT MOVES INTO THE TENNESSEE VALLEY.
REMAINDER OF THE SHORT TERM WILL BE QUIET AS BROAD HIGH PRESSURE
TAKES OVER ACROSS THE MIDWEST AND OHIO VALLEY. A MUCH COOLER DRIER
AIRMASS WILL BRING A REFRESHING CHANGE FOR THE SECOND HALF OF THE
WEEKEND AND INTO EARLY NEXT WEEK.
TEMPS...MAVMOS APPEARED REASONABLE THROUGHOUT THE SHORT TERM AS
HIGHS FALL BACK INTO THE 70S BOTH SATURDAY AND SUNDAY. ONE LAST
HUMID NIGHT FOR TONIGHT WITH MUCH MORE COMFORTABLE TEMPS FOR
SATURDAY/SUNDAY NIGHTS INTO THE LOWER AND MIDDLE 50S...WITH MAYBE
EVEN A FEW RURAL LOCATIONS FALLING INTO THE UPPER 40S.
&&
.LONG TERM /MONDAY THROUGH THURSDAY NIGHT/...
ISSUED AT 342 AM EDT FRI SEP 5 2014
DRY CONDITIONS CAN BE EXPECTED ON MONDAY WITH ZONAL FLOW ALOFT AND
WEAK HIGH PRESSURE STILL AT THE SURFACE. HOWEVER...THE PATTERN WILL
QUICKLY SHIFT BY TUESDAY AS A BROAD UPPER TROUGH ENTERS THE AREA.
WIDESPREAD SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS CENTRAL
INDIANA AS EARLY AS TUESDAY MORNING...WITH INCREASING CHANCES
THROUGH THE COURSE OF THE EXTENDED PERIOD AS A COLD FRONT TRACKS
ACROSS THE AREA ON WEDNESDAY NIGHT/THURSDAY. PRECIP CHANCES WILL
TAPER OFF TOWARD THE END OF THE PERIOD...BUT WILL KEEP MENTION OF
SHOWERS AND THUNDERSTORMS IN THE FORECAST THROUGH THURSDAY NIGHT TO
ACCOUNT FOR PASSAGE OF UPPER LOW. TEMPS WILL CONTINUE TO DROP WELL
BELOW NORMAL THROUGH THE COURSE OF THE EXTENDED PERIOD WITH HIGH TEMPS
ONLY IN THE UPPER 60S/LOW 70S BY FRIDAY.
&&
.AVIATION /DISCUSSION FOR THE 05/1200Z TAF ISSUANCE/...
ISSUED AT 711 AM EDT FRI SEP 5 2014
WIDESPREAD SHOWERS AND THUNDERSTORMS WILL SPREAD OVER TAF SITES
THIS AFTERNOON AS A COLD FRONT ENTERS THE AREA. ACTIVITY WILL
START ENTERING KLAF BETWEEN FRI 18-21Z...MOVING SOUTHEAST THROUGH
THE REMAINING SITES. CONVECTION WILL INTENSIFY DURING THE SAT
00Z-06Z TIME FRAME. CONDITIONS WILL GENERALLY BE AT VFR CATEGORY
EXCEPT DURING ANY STRONG STORMS THAT COULD RESULT IN BRIEF MVFR
CONDITIONS. IT ISN/T UNTIL AFTER SAT 06Z THAT CONDITIONS WILL
QUICKLY PLUMMET TO MVFR OR WORSE AS CEILINGS LOWER FURTHER.
WINDS WILL BE SOUTHWESTERLY INTO THE EVENING HOURS...AND A LITTLE
BREEZY WITH SUSTAINED SPEEDS OF 10 TO 12 KTS. WINDS WILL VEER TO
THE NORTHWEST TONIGHT AFTER FRONTAL PASSAGE...SUSTAINED AT
8 TO 10 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....TDUD
AVIATION...TDUD
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
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WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS DES MOINES IA
638 AM CDT FRI SEP 5 2014
...UPDATED AVIATION DISCUSSION...
.SYNOPSIS...
ISSUED AT 304 AM CDT FRI SEP 5 2014
COLD FRONT OVER SOUTHEAST IOWA WILL MOVE SOUTHEAST OF IA TODAY AS
A WAVE LIFTS NORTHEAST ALONG THE FRONT THIS AFTERNOON AND EVENING.
HIGH PRESSURE WILL BUILD INTO THE STATE TODAY AND TONIGHT. THE
NEXT FRONTAL SYSTEM WILL APPROACH THE STATE MONDAY...MOVING SLOWLY
THROUGH IOWA THROUGH MID WEEK.
&&
.SHORT TERM /TODAY/...
ISSUED AT 304 AM CDT FRI SEP 5 2014
SLOW MOVING COLD FRONT WILL FINALLY CLEAR THE FAR SOUTHEAST
CORNER OF THE FORECAST AREA B/T 12-14Z THIS MORNING. THE
ASSOCIATED BROKEN LINE OF WEAK CONVECTION LOOKS TO LINGER
THROUGH SUNRISE BEFORE THE LLJ WEAKENS AND RESULTS IN STORMS
DIMINISHING IN INTENSITY AND COVERAGE BY 12Z OR EVEN SOONER. HAVE
LIKELY POPS GOING THROUGH THIS TIME...GENERALLY B/T THE HWY 20 AND
HWY 30 CORRIDORS...THEN CHANCE POPS ACROSS THE SOUTHERN HALF OF
THE FORECAST AREA THE REMAINDER OF THE MORNING.
NEXT SHORTWAVE LOOKS TO ENTER THE SOUTHERN PORTION OF THE STATE
LATER THIS MORNING INTO THE AFTERNOON HOURS AND BRINGS ANOTHER
ROUND OF SHOWERS/TSTMS ACROSS THE FORECAST AREA INTO THIS
EVENING. BROAD LARGE SCALE FORCING WITH THIS SHORTWAVE AND ENOUGH
THETA-E ADVECTION TO WARRANT CHANCE POPS ACROSS THE SOUTHERN TWO-
THIRDS OF THE FORECAST LATE THIS MORNING AND INTO THE AFTERNOON.
THE 05.05Z HRRR SEEMS A BIT TOO FAST WITH RAIN BUT AGREE WITH THE
COVERAGE ACROSS CENTRAL IOWA. THE 05.00Z HOPWRF SIMILAR WITH THE
COVERAGE BUT THINK IT HAS A BETTER HANDLE ON THE TIMING OF THE
PRECIP AND LEANED TOWARD THE HOPWRF FOR POP TRENDS TODAY.
CONSIDERED A NON-DIURNAL TEMPERATURE TREND TODAY BUT SHOULD WARM UP
ENOUGH LATER THIS MORNING INTO THE AFTERNOON ACROSS MUCH OF THE
FORECAST AREA...SO HAD LOW CONFIDENCE IT WOULD BE WIDESPREAD ENOUGH
TO MENTION.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 304 AM CDT FRI SEP 5 2014
CLEARING WILL SPREAD SOUTHEAST A HIGH PRESSURE BUILDS IN TO THE
STATE. THE WEEKEND LOOKS TO BE A QUITE WEEKEND WITH NO RAINFALL
EXPECTED AND TEMPERATURES BELOW NORMAL.
THE WEATHER PATTERN WILL BECOME MORE ACTIVE NEXT WEEK. DECENT
THETA-E ADVECTION BEGINS BY MONDAY MORNING AND WILL CONTINUE
PERIODICALLY THROUGH MID WEEK. RAINFALL AMOUNTS WILL HINGE ON HOW
MUCH OF THE MOISTURE FROM "NORBERT" IS PULLED INTO THE SYSTEM. IT
APPEARS THAT THE BULK OF THE MOISTURE WILL BE SWEPT EAST PASSING
OVER SOUTHERN IA OR FARTHER SOUTH. A STRONG UPPER TROUGH WILL
CARVE OUT FOR THE FOLLOWING WEEKEND. MODEL CONTINUITY IS DECENT
WITH THE MACRO SYSTEMS...DIFFERING IN DETAIL...BUT THE MESSAGE OF
SHARPLY COLDER IS PLAYED BY ALL.
&&
.AVIATION...05/12Z
ISSUED AT 638 AM CDT FRI SEP 5 2014
MVFR CIGS LOOK TO AFFECT OTM THROUGH THE MID MORNING AND HAVE
HANDLED VIA TEMPO. SCATTERED SHOWER ACTIVITY WILL CONTINUE TO
DIMINISH THIS MORNING AND HAVE VCSH OR VCTS MENTIONED THIS MORNING
WITH LOW CONFIDENCE RAIN LASTING LONGER THAN AN HOUR AT TIMES.
OTHERWISE...CAA SETS IN THROUGH THE AFTERNOON WITH NEXT WAVE
BRINGING ADDITIONAL RAIN CHANCES OVER SOUTHERN IOWA. MAY ONLY
AFFECT OTM ATTM.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...MS SEP 14
SHORT TERM...PODRAZIK
LONG TERM...MS SEP 14
AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1009 AM EDT FRI SEP 5 2014
.SYNOPSIS...
HIGH PRESSURE ALONG THE EAST COAST WILL PROVIDE A VERY WARM AND HUMID
SUMMER LIKE AFTERNOON FOR THE REGION. THERE IS A CHANCE FOR
AFTERNOON SHOWERS AND THUNDERSTORMS ESPECIALLY IN NORTHEAST
PENNSYLVANIA AND ALSO IN NORTH CENTRAL NEW YORK. AN APPROACHING
COLD FRONT WILL BRING THE LIKELIHOOD OF MORE SHOWERS AND
THUNDERSTORMS, STARTING LATE TONIGHT, THEN LASTING THROUGH MUCH OF
SATURDAY. ONCE THIS FRONT PUSHES OFF THE COAST, A NEW HIGH
PRESSURE SYSTEM WILL ADVANCE TOWARD THE REGION SUNDAY, WITH DRIER
AND COOLER WEATHER.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL WAVE MOVING ACRS THE
OHIO VALLEY WHICH WAS SUPPORTG SOME CONVECTIVE ACVTY OVER THE
UPPER LAKES. THE SOUTHERN EDGE OF THIS WAS AFFECTING SRN ONT AND
LAKE ONTARIO AT THIS TIME. THIS ACVTY WAS MOVING EASTWARD AS THE
UPPER LEVEL WAVE PROPAGATES TO THE E-NE THIS AFTERNOON. THE
GFS...NAM...EURO...CMC AND RAP ALL SHOW THIS UPPER LEVEL FEATURE
WORKING ACRS NY AND PA BTWN 18Z AND 00Z WITH ONLY SOME SLIGHT
COOLING ALOFT ON THE ORDER OF BARELY 1C AT 500 MB. THIS WILL OCCUR
IN CONCERT WITH THE MAX HEATING OF THE AFTERNOON AND FAIRLY RICH
BOUNDARY LAYER MOISTURE ESPECIALLY ALONG THE LAKE ONTARIO PLAIN
AND IN NE PA. HENCE WHERE THERE IS ENUF INSTABILITY THERE WILL BE
A FEW SHRA OR TSRA POPPING UP.
MODEL INSTABILITY FIELDS FROM THE RAP...GFS...NAM ALSO SHOW A
RIBBON OF INSTABILITY OVER 1000 J/KG ALONG THE LAKE ONTARIO PLAIN
AS WELL AS ACRS NE PA WHERE CAPES CUD EXCEED 2000 J/KG (AS PER 06Z
NAM AT LEAST) WITH A MINIMUM IN CAPE ACROSS FAR NRN PA AND SC NY.
BELIEVE SOME ISLD TO SCT TSRA WILL FIRE THIS AFTERNOON WHEN THIS
WAVE INTERACTS WITHIN THESE INSTABILITY AXISES WITH COVERAGE IN
THE ISLD TO SCT RANGE IN NC NY AND NE PA SO HAVE ADDED POPS FOR
LATER TODAY IN NE PA TO ACCOUNT FOR. JUST TWEAKED POPS IN NC NY
FROM EARLIER SHIFT. 06Z NAM SOUNDING ACTUALLY HAS 3000 J/KG OF
CAPE AT AVP ARND 22-00Z! THE FORCING IS WEAK BUT IF SOMETHING
FIRES THERE CUD BE SOME VERY HEAVY RAIN LOCALLY WITH PWATS AROUND
1.75 INCHES AND THE POTENTIAL FOR STORMS TO ANCHOR ON THE
MOUNTAINS IN SUCH A WEAK FLOW REGIME. THE WINDS ARE STRONGER IN
THE LOW-LEVELS BETWEEN 0 AND 3 KM THEN WEAKEN ARND 3 TO 6 KM AND
THEN STRENGTHEN AGAIN. WE WILL HAVE TO WATCH THIS CAREFULLY THIS
AFTERNOON. ANYTHING THAT FIRES DOWN IN NE PA CUD CAUSE HEAVY RAIN.
AND.... IF CAPE VALUES ACTUALLY REACH 3000 J/KG AS PER 06Z NAM YOU
CANT RULE OUT A MICROBURST...EVEN IF CAPES EXCEED 2000 J/KG. WILL
MENTION IN HWO FOR NE PA THIS AFTERNOON. FARTHER N IN NC NY...ACVTY
LIKELY WILL BE MORE ISOLATED WITH LESS INSTABILITY. BUT THERE WAS STRGR
WIND FIELDS. THIS LIKELY WILL LESSENING THREAT FOR ANY SLOW MOVING HEAVY
RAIN PRODUCING STORMS. CAPES CUD REACH 500 TO 1000 J/KG WITH SOME
LOW-LEVEL SHEAR ARND 15-20 KNOTS BUT WEAKER DEEP LAYER SHEAR. NOT
EXPECTING ANY ORGANIZED SVR ACVTY IN NC NY AS A RESULT UNLESS
CAPES GET HIGHER THAN PROJECTED.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
430 AM UPDATE... OVERALL...MODEL GUIDANCE REMAINS SIMILAR TO THE
LAST SVRL RUNS...IN SHOWING AN ADVANCING SFC COLD FRNT THROUGH THE
AREA ON SAT...FOLLOWED BY HIGH PRES AND S/WV RIDGING ALOFT SUN.
SHWRS/TSTMS ALG AND AHD OF THE COLD FRNT SHOULD INCREASE IN
COVERAGE LTR TNT OVER OUR NRN AND WRN ZNS...WITH A BAND OF FAIRLY
WIDESPREAD CONVECTION PUSHING SEWD THROUGH CNY/NE PA DURG THE DAY
SAT. WE`LL CONTINUE TO EMPLOY LIKELY POPS FOR MUCH OF THIS TIME
FRAME.
THE POTENTIAL FOR STG/SVR STORMS ON SAT LOOKS MUDDLED OVER THE
FA...WITH SIG CLOUD COVER LIKELY TO LIMIT DESTABILIZATION FOR AT
LEAST THE NWRN HALF OF THE CWA (CNTRL SRN TIER...FINGER LKS...WRN
MOHAWK VLY...AND SRN TUG HILL RGNS OF NY). HOWEVER...FARTHER S AND
E...THERE ARE NOW SOME INDICATIONS THAT THE SFC BNDRY MAY SLOW
JUST ENUF (ROUGHLY AN 18-21Z FROPA) TO ALLOW SOME MODEST HEATING
(TEMPS INTO THE LWR 80S)...WITH PROGGED ML CAPES IN THE
NEIGHBORHOOD OF 1000 J/KG. GIVEN DEEP-LYRD SHEAR OF 25-30 KT BY
THIS TIME...THE ENVIR COULD BECOME MARGINALLY SUPPORTIVE OF STG
GUSTY WINDS. THUS...WE`VE HIGHLIGHTED THIS POTENTIAL IN THE HWO
SAT FOR OUR FAR ERN AND SRN ZNS (OTSEGO CNTY...THE WRN
CATSKILLS...THE POCONOS...AND THE WILKES-BARRE SCRANTON AREA).
SPURRED ON BY A FAIRLY AMPLIFIED S/WV...THE COLD FRNT SHOULD
PROGRESS OFF THE COAST SAT NIGHT...WITH ANY LINGERING CONVECTION
ENDING EARLY IN THE EVE.
SUN SHOULD BE COOLER (HIGHS MAINLY IN THE 70-75 RANGE)...UNDER PTLY TO
MOSTLY SUNNY SKIES...WITH A SFC RIDGE BLDG IN FROM THE W.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
130 PM UPDATE...
SPRAWLING HIGH PRESSURE WILL INFLUENCE THE REGION`S WX FOR THE
FIRST SVRL DAYS OF THE LONG TERM. SYNOPTIC PATTERN WL TRANSITION
FM ZONAL FLOW ALOFT TO SWRLY FLOW BY MID-WEEK AS ANOTHER S/WV TROF
TRACKS IN FM THE UPR MIDWEST. THIS WL SPELL OUR NEXT CHC FOR
SHOWERS/TSTMS ON RETURN FLOW ASSOC WITH SFC TROF AND ULTIMATELY
LOPRES RIDING UP SPINE OF THE APPALACHIANS. THIS WL KEEP AREA IN
MOIST/CLDY AIRMASS WITH CHC POPS EACH PD THRU END OF EXTNDD PD
LOWS IN THE 50S/HIGHS IN THE 70S WHICH IS TYPICAL FOR THIS TIME OF
YR.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
RESTRICTIONS EXPECTED AT KELM AND KAVP THIS MORNING, OTHERWISE VFR
THROUGH TONIGHT.
AT KELM DENSE FOG HAS FINALLY SET IN WITH VLIFR VSBYS/CIGS THROUGH
13Z, AND A SLOW IMPROVEMENT TO VFR BY 14Z. AT KAVP A MARINE LAYER
THAT HAS PRODUCED MVFR CIGS WILL SLOWLY BREAK UP BY 13Z.
FOR THE REST OF TODAY HIGH CLOUDS ESPECIALLY OVER THE NY TERMINALS
WILL GRADUALLY LOWER TONIGHT TO AROUND 10KFT. SHOWERS POSSIBLE NY
TERMINALS TOWARD DAYBREAK SATURDAY.
OUTLOOK...
SAT...MVFR/IFR LIKELY IN OCNL SHRA/TSRA.
SUN-TUE...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...MLJ
LONG TERM...PVN
AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS RALEIGH NC
730 AM EDT FRI SEP 5 2014
.SYNOPSIS...HIGH PRESSURE ALOFT WILL EXTEND ACROSS CENTRAL NC
THROUGH SATURDAY. A COLD FRONT WILL CROSS THE AREA SATURDAY
NIGHT AND STALL TO OUR SOUTH ON SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 315 AM FRIDAY...
THE SUB-TROPICAL RIDGE HOLDS ON ACROSS THE SOUTHEAST US FOR ANOTHER
DAY...AS THE BERMUDA HIGH BUILDS WESTWARD ACROSS THE REGION. THE
WEAK FRONTAL ZONE NEAR THE NC/VA BORDER ON THURSDAY HAS ESSENTIALLY
WASHED OUT...LEAVING MAINLY THE SEABREEZE AND TERRAIN INDUCED
DIFFERENTIAL HEATING AS THE PRIMARY TRIGGERS FOR CONVECTION TODAY.
WHILE NOT A PROMINENT ON RADAR AS WAS THE CASE YESTERDAY...LINGERING
OUTFLOW BOUNDARIES MAY ALSO TRIGGER SOME CONVECTION. THE HRRR SHOWS
SOME LATE MORNING SHOWERS OVER THE NORTHWEST PIEDMONT...WHICH SEEMS
SOMEWHAT REASONABLE GIVEN THAT IT WAS ONE OF THE LAST PLACES TO HAVE
SHOWERS THIS MORNING. MODERATE INSTABILITY OF 1000-2000 J/KG MLCAPE
SHOULD DEVELOP THIS AFTERNOON...BUT WITH VERY WEAK
SHEAR...CONVECTION IS NOT EXPECTED TO BE PARTICULARLY INTENSE.
WILL MOSTLY MAINTAIN THE PREVIOUS FORECAST POPS OF CHANCES IN THE
NORTHWEST AND SOUTHEAST...WITH A SLIGHT CHANCE OVER THE NORTHWEST
PIEDMONT AREA THIS MORNING GIVEN THE REASONING ABOVE. HIGHS AROUND
90 DEGREES.
&&
.SHORT TERM /SATURDAY AND SATURDAY NIGHT/...
AS OF 320 AM FRIDAY...
SAT AND SAT NIGHT: ONE MORE DAY OF HEAT...IN ADVANCE OF A COLD FRONT
FORECAST TO SETTLE SOUTHEASTWARD TO A POSITION FROM EASTERN NEW
ENGLAND TO THE CENTRAL AND SOUTHERN APPALACHIANS BY SAT EVENING. A
PRE-FRONTAL TROUGH AND THE SEA-BREEZE WILL FOCUS INITIALLY DIURNAL
HEATING-DRIVEN AFTERNOON AND EVENING CONVECTION OVER THE
NORTHWESTERN AND SOUTHERN PORTIONS OF THE RAH CWFA...WITH THE LATTER
POSSIBLY ENHANCED BY THE SLOW NORTHWARD DRIFT OF AN AREA OF
DISTURBED WEATHER FORECAST TO DRIFT NORTH FROM THE EAST COAST OF FL
TO EASTERN GA AND SC. SHOWERS AND STORMS WILL LIKELY PERSIST
THROUGHOUT THE NIGHT...PARTICULARLY NORTH OF THE SANDHILLS AND
SOUTHERN COASTAL PLAIN...AS THE AFOREMENTIONED COLD FRONT OVERTAKES
THE PRE-FRONTAL TROUGH OVER NORTHERN AND CENTRAL NC OVERNIGHT. LOWS
IN THE MIDDLE TO UPPER 60S IN DEVELOPING POST-FRONTAL CAA OVER THE
NORTHERN PIEDMONT...TO LOWER 70S OVER THE WARM SECTOR IN THE
SANDHILLS AND SOUTHERN COASTAL PLAIN.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 340 AM FRIDAY...
SUN: THE COLD FRONT...WHOSE TIMING HAS SLOWED VERSUS THE FASTER
TREND IN NWP GUIDANCE NOTED YESTERDAY...IS NOW FORECAST TO ROUGHLY
BISECT CENTRAL NC FROM NW TO SE AT THE START OF THE DAY SUN...THEN
ONLY SLOWLY DRIFT SOUTHEASTWARD THROUGHOUT THE DAY. THE RESULT WILL
BE NUMEROUS TO WIDESPREAD SHOWERS AND STORMS OVER A LARGER PART OF
THE CWFA...OVER ALL BUT THE FAR NORTHERN AND NW PIEDMONT WHERE POP
WILL BE IN THE CHANCE RANGE...THROUGH THE AFTERNOON. NOT AS
WARM...WITH HIGHS IN THE LOWER 80S NW...TO UPPER 80S TOWARD KFAY-
KGSB-KCTZ. IN AN ENVIRONMENT CHARACTERIZED BY PRECIPITABLE WATER
VALUES NEAR TWO INCHES...FLOODING IN URBAN AND OTHER FLOOD PRONE
AREAS WILL BE POSSIBLE.
SUN NIGHT-MON NIGHT: THE FRONT IS THEN FORECAST TO SLOW AS IT INTO
EASTERN NC (NOT AS FAR EAST AS EARLIER PROGGED). FRONTAL CONVERGENCE
AND INVOF A WAVE OR TWO OF LOW PRESSURE FORECAST TO RIPPLE ALONG THE
FRONT...AND ISENTROPIC UPGLIDE ATOP IT...WILL PROMOTE A LIKELY
PROBABILITY OF SHOWERS AND STORMS THROUGH MON...PARTICULARLY OVER
THE EASTERN PIEDMONT AND COASTAL PLAIN. NORTHEASTERLY FLOW AND
ASSOCIATED MOSTLY CLOUDY CONDITIONS...AND CHANCE OF SHOWERS...WILL
PREVAIL OVER THE SOUTHERN AND WESTERN PIEDMONT. COOLER WITH HIGHS
MOSTLY IN THE 70S...AND LOWS 65 TO 70.
TUE-THU: SFC WAVES DEPART WITH LESSENING INFLUENCE OF THE
NORTHEASTERLY FLOW...WITH ASSOCIATED DECREASING CLOUDINESS...AND
MODERATION INTO THE UPPER 70S TO MIDDLE 80S. SHOWER AND STORM
CHANCES...JUST SLIGHT TO LOW CHANCE ONES...SHOULD BE CONFINED TO
EASTERN AREAS TUE...WITH TYPICAL POP DISTRIBUTION INVOF THE SEA
BREEZE AND MOUNTAINS AS CENTRAL NC REMAINS BETWEEN THE DEPARTING SFC
WAVES AND THE NEXT FRONT FORECAST TO ARRIVE LATE NEXT WEEK.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 730 AM FRIDAY...
A FEW AREAS OF LOW STRATUS ARE CURRENTLY IMPACTING KFAY...KRDU AND
KRWI. RECENT OBS SUGGEST THE STRATUS WILL LIFT VERY QUICKLY THIS
MORNING...AND VFR CONDITIONS ARE EXPECTED AREA-WIDE BY 14Z. SHOWERS
AND STORMS ARE POSSIBLE AGAIN THIS AFTERNOON/EVENING...MORE LIKELY
AT KFAY AND KGSO/KINT...THOUGH THE OVERALL COVERAGE IS EXPECTED TO
BE LESS THAN IN THE PAST COUPLE OF DAYS. TONIGHT...WITH HIGH
PRESSURE STILL IN CONTROL AND POTENTIALLY LESS CLOUD COVER THAN IN
PREVIOUS NIGHTS...FOG MAY BE A CONCERN AFTER MIDNIGHT.
OUTLOOK...A COLD FRONT WILL APPROACH THE REGION LATE SATURDAY INTO
SUNDAY...LEADING TO INCREASED CHANCES OF SHOWERS AND THUNDERSTORMS.
THE BEST CHANCES OF CONVECTION WILL SHIFT TOWARDS THE SOUTH AND EAST
BY EARLY NEXT WEEK AS THE FRONT STALLS NEAR THE COAST. LOW
CLOUDS/FOG WILL BE POSSIBLE EACH MORNING...WITH POSSIBLY AN
EXTENDED PERIOD OF SUB VFR CONDITIONS EARLY NEXT WEEK AS HIGH
PRESSURE EXTENDS DOWN INTO THE REGION AND MOIST NORTHEASTERLY FLOW
PREVAILS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...BLS
SHORT TERM...MWS
LONG TERM...MWS
AVIATION...KRD/BLS
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1201 PM EDT FRI SEP 5 2014
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO DRIFT EAST OF THE MID ATLANTIC
COAST TODAY. A COLD FRONT WILL PUSH SOUTHEAST ACROSS THE STATE ON
SATURDAY. HIGH PRESSURE OVER THE MIDWEST WILL THEN SLIDE ACROSS
PENNSYLVANIA SUNDAY INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
REGIONAL VIS LOOP SHOWING STUBBORN LOW CLOUDS/AND SOME 3-4SM FOG
LINGERING THROUGHOUT THE LOWER SUSQ VALLEY WITHIN THE REGION OF
HIGHEST MOISTURE AND WEAK LLVL...SERLY FLOW.
THIS CLOUD AREA WILL SLOWLY ERODE FROM ITS EDGES THROUGH
18Z...KEEPING TEMPS A FEW DEG F BEHIND THOSE ELSEWHERE ACROSS THE
CWA. EXPECT A QUICK SPIKE IN THE TEMPS IN THE LOWER SUSQ REGION
AFTER 18Z UNDER PLENTY OF SUNSHINE THERE...AND AREA-WIDE.
IT DOESN/T GET ANY SOUPIER IN SEPTEMBER HERE IN CENTRAL PENN THAN
IT WAS EARLIER THIS MORNING...WITH DENSE FOG IN THE U60S TO LOWER
70S.
HIGHEST PWAT AIR /NEAR 2.0 INCHES/ AND COOLEST MID-LEVEL TEMPS OF
JUST AROUND 7C WILL BE FOUND ACROSS THE LOWER SUSQ VALLEY THIS
AFTERNOON. IN CONTRAST...THE LOWEST PWATS AND WARMER TEMPS ALOFT
/8-9C AT 700 MB/ WILL OCCUR ACROSS THE KBFD VCNTY AND POINTS WEST.
LATEST HRRR CONFINES PRACTICALLY ALL OF THE MID TO LATE AFTERNOON
CONVECTION ACROSS FAR SCENT PENN AND THE LOWER SUSQ VALLEY...WITH
JUST A SPECKLING OF A FEW STRAY SHOWERS/TSRA NEAR THE ALLEGHENY
FRONT UP TO I-80.
THEREFORE...THE CURRENT RUNNING FCST OF ISOLATED TO SCATTERED
SHOWERS AND TSRA ACROSS SOUTHERN PENN AND THE LOWER SUSQ VALLEY
LOOKS IN GOOD SHARP ATTM WITH MINIMAL CHANGES EXPECTED WITH THIS
MIDDAY UPDATE. A RIBBON OF LOWER PWAT AIR WILL BE SITUATED ACROSS
THE REGION NORTH OF A LINE FROM KBFD TO KUNV AND KAVP.
AS THE ISOLATED-SCT PULSE-TYPE TSRA DEVELOP ACROSS THE SOUTHERN
COUNTIES DURING THE AFTN...WILL HAVE TO WATCH FOR LOCALLY
EXCESSIVE RAINFALL...AS ANY STORMS WILL BE SLOW-MOVERS DUE TO
WEAK FLOW ALOFT. CONVECTION-ALLOWING MDL DATA HINTS AT THIS
POTENTIAL WITH SPOT AMTS OF OVR 3 INCHES ACROSS THE LOWER SUSQ
VALLEY.
GEFS 925/850 TEMPS SUPPORT HIGH TEMPS IN THE M-U80S...WITH THE
GREATEST DEPARTURES FROM AVERAGE ACROSS THE W MTNS. WHEN COMBINED
WITH HIGH HUMIDITY...APPARENT TEMPS WILL RANGE FROM THE U80S TO
L90S...PERHAPS THE WARMEST WE/LL SEE UNTIL NEXT YEAR.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
IN THE ABSENCE OF LG SCALE FORCING...DIURNALLY-DRIVEN SCT
CONVECTION ACROSS SOUTHERN PA SHOULD DIE OFF SHORTLY AFTER SUNSET.
TRANQUIL AND VERY WARM CONDS EXPECTED FOR THE REST OF THE NIGHT
OVR MOST OF CENTRAL PA...AS COLD FRONT REMAINS WEST OF THE AREA.
MDL TIMING OF COLD FRONT SUGGESTS SHRA/TSRA WILL MOVE INTO THE NW
MTNS ARND OR SHORTLY AFTER DAWN SATURDAY.
HAVE INCREASED POPS TO NR 80 PCT SATURDAY FOR PASSAGE OF COLD
FRONT BASED ON ABUNDANCE OF PRE-FRONTAL MOISTURE AND FAIRLY STRONG
FORCING AHEAD OF APPROACHING SHORTWAVE...AS IMPLIED BY MDL
500-300MB Q-VEC CONVERGENCE FIELDS. GEFS PWATS RUNNING BTWN 1-2SD
ABV NORMAL IN ADVANCE OF CDFRONT. 00Z GEFS/03Z SREF DATA ALSO
BOTH SUPPORT CATEGORICAL POPS ACROSS MOST OF CENTRAL PA. MORNING
SHOWERS ACROSS THE NW MTNS SHOULD GIVE WAY TO PM TSRA OVR THE
SOUTHERN COUNTIES...WHERE EARLY HEATING WILL RESULT IN A
MODERATELY UNSTABLE PRE-FRONTAL AIR MASS BY AFTN. HOWEVER...FAIRLY
MODEST MID LVL WINDS AND DEEP LYR SHEAR POINT TOWARD A LIMITED SVR
WX THREAT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
*COOLER/DRY WEATHER SUNDAY INTO MONDAY
*NEAR AVERAGE TEMPERATURES AND MORE UNSETTLED CONDITIONS TUE-THU
THE REGIONAL PATTERN ALOFT WILL FEATURE INCREASING TROUGHINESS
THROUGH THE MEDIUM RANGE PERIOD...WITH THE GLOBAL ENSEMBLE MEANS
SHOWING A CORE OF NEGATIVE HEIGHT ANOMALIES OVER THE UPPER MIDWEST
AND GREAT LAKES REGIONS BY THE MIDDLE TO LATER PART OF NEXT WEEK
/SEPT 11-12TH/. OVERALL...THE NAEFS/GEFS AND ECENS ALL SIGNAL A
TRANSITION TOWARD A HIGHER AMPLITUDE PATTERN PARTICULARLY ACROSS
SOUTH CENTRAL CANADA.
AN ELONGATED COLD FRONT TRAILING A RELATIVELY STRONG SFC LOW OVER
NEWFOUNDLAND/LABRADOR WILL BE PASSING SOUTH OF PA SAT NIGHT. A
MODIFIED CANADIAN HIGH BUILDING SWD INTO THE CENTRAL PLAINS WILL
EVENTUALLY SHIFT EWD THROUGH THE NORTHEAST STATES AND MOVE INTO
THE MARITIMES BY NEXT WED.
SHRA/TSRA WILL END FROM NW-SE SAT NGT WITH MUCH DRIER AIR
FILTERING IN FOR SUNDAY. DRY WX SHOULD CONTINUE INTO EARLY NEXT
WEEK BEFORE CONDS TURN MORE UNSETTLED. EASTERLY WINDS TO THE SOUTH
OF HP CELL MOVG INTO THE MARITIMES ARE SUGGESTIVE OF A COOL-AIR
WEDGE OVER THE MID-ATLC WHICH SHOULD DAYTIME HIGHS NEAR AVG.
&&
.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
LINGERING...PATCHY 3-4SM FOG AND IFR CIGS ACROSS THE LOWER SUSQ
VALLEY WILL DISSIPATE BETWEEN 17-18Z. ELSWHERE...PLENTY OF SUNSHINE
WILL OCCUR WITH VSBYS IN THE 5-10SM RANGE FOR THE REST OF TODAY.
FOCUS THIS AFTERNOON SHIFTS TOWARD POTENTIAL FOR SCT DIURNAL
CONVECTION ACROSS FAR SRN AND SOUTHEAST PA. PWATS ARE PROJECTED TO
APPROACH 2 INCHES IN THIS AREA AND HEATING OF THIS MOIST/UNSTABLE
AIR MASS SHOULD RESULT IN MODERATE CAPES OF ARND 2000J/JG ACROSS
THE LOWER SUSQ VALLEY BASED ON LATEST OPER MODEL AND GEFS OUTPUT.
SCT PULSE- TYPE TSRA SHOULD DEVELOP ACROSS THE SOUTHERN COUNTIES
BRINGING LOCAL RESTRICTIONS AS CONVECTIVE TEMP IS REACHED DURING
THE AFTN...AND ANY STORMS WILL BE SLOW- MOVERS DUE TO WEAK FLOW
ALOFT.
HIGH DEWPOINTS REMAIN IN PLACE TONIGHT AHEAD OF AN APPROACHING
COLD FRONT. THIS WILL LEAD TO REDEVELOPMENT OF FOG/HAZE...AND AN
ENCROACHING MVFR CLOUD DECK ALONG WITH A CHANCE FOR SHOWERS AFTER
06Z IN THE NW.
OUTLOOK...
SAT...AM SHRA/LOW CIGS POSS NW MTNS. PM TSRA IMPACTS POSS
ELSEWHERE.
SUN...AM FOG POSS NW MTNS.
MON...PATCHY AM VALLEY FOG POSS.
TUE...CHC SHOWERS/TSTMS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD/LAMBERT
NEAR TERM...FITZGERALD/LAMBERT
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD/STEINBUGL
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
751 AM EDT FRI SEP 5 2014
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO DRIFT EAST OF THE MID ATLANTIC
COAST TODAY. A COLD FRONT WILL PUSH SOUTHEAST ACROSS THE STATE ON
SATURDAY. HIGH PRESSURE OVER THE MIDWEST WILL THEN SLIDE ACROSS
PENNSYLVANIA SUNDAY INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
11-3.9 MICRON SATL IMAGERY SHOWING EXTENSIVE FOG IN THE VALLEYS OF
CENTRAL PA EARLY THIS MORNING...AS WELL AS STRATUS ACROSS EASTERN
PA. THE LOW CLOUDS AND FOG SHOULD BURN OFF BY 13Z-14Z BASED ON
CLIMATOLOGY AND LATEST HRRR OUTPUT. FOCUS THEN SHIFTS TOWARD
POTENTIAL OF SCT DIURNAL CONVECTION ACROSS SOUTHEAST PA. PWATS ARE
PROJECTED TO APPROACH 2 INCHES IN THIS AREA AND HEATING OF THIS
MOIST/UNSTABLE AIR MASS SHOULD RESULT IN MODERATE CAPES OF ARND
2000J/JG BY THIS AFTN ACROSS THE LOWER SUSQ VALLEY BASED ON
LATEST OPER MODEL AND GEFS OUTPUT. SCT PULSE-TYPE TSRA SHOULD
DEVELOP ACROSS THE SOUTHERN COUNTIES AS CONVECTIVE TEMP IS REACHED
DURING THE AFTN. WILL HAVE TO WATCH FOR LOCALLY EXCESSIVE
RAINFALL...AS ANY STORMS WILL BE SLOW-MOVERS DUE TO WEAK FLOW
ALOFT. CONVECTION-ALLOWING MDL DATA HINTS AT THIS POTENTIAL WITH
SPOT AMTS OF OVR 3 INCHES ACROSS THE LOWER SUSQ VALLEY.
GEFS 925/850 TEMPS SUPPORT HIGH TEMPS IN THE M-U80S...WITH THE
GREATEST DEPARTURES FROM AVERAGE ACROSS THE W MTNS. WHEN COMBINED
WITH HIGH HUMIDITY...APPARENT TEMPS WILL RANGE FROM THE U80S TO
L90S...PERHAPS THE WARMEST WE/LL SEE UNTIL NEXT YEAR.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
IN THE ABSENCE OF LG SCALE FORCING...DIURNALLY-DRIVEN SCT
CONVECTION ACROSS SOUTHERN PA SHOULD DIE OFF SHORTLY AFTER SUNSET.
TRANQUIL AND VERY WARM CONDS EXPECTED FOR THE REST OF THE NIGHT
OVR MOST OF CENTRAL PA...AS COLD FRONT REMAINS WEST OF THE AREA.
MDL TIMING OF COLD FRONT SUGGESTS SHRA/TSRA WILL MOVE INTO THE NW
MTNS ARND OR SHORTLY AFTER DAWN SATURDAY.
HAVE INCREASED POPS TO NR 80 PCT SATURDAY FOR PASSAGE OF COLD
FRONT BASED ON ABUNDANCE OF PRE-FRONTAL MOISTURE AND FAIRLY STRONG
FORCING AHEAD OF APPROACHING SHORTWAVE...AS IMPLIED BY MDL
500-300MB Q-VEC CONVERGENCE FIELDS. GEFS PWATS RUNNING BTWN 1-2SD
ABV NORMAL IN ADVANCE OF CDFRONT. 00Z GEFS/03Z SREF DATA ALSO
BOTH SUPPORT CATEGORICAL POPS ACROSS MOST OF CENTRAL PA. MORNING
SHOWERS ACROSS THE NW MTNS SHOULD GIVE WAY TO PM TSRA OVR THE
SOUTHERN COUNTIES...WHERE EARLY HEATING WILL RESULT IN A
MODERATELY UNSTABLE PRE-FRONTAL AIR MASS BY AFTN. HOWEVER...FAIRLY
MODEST MID LVL WINDS AND DEEP LYR SHEAR POINT TOWARD A LIMITED SVR
WX THREAT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
*COOLER/DRY WEATHER SUNDAY INTO MONDAY
*NEAR AVERAGE TEMPERATURES AND MORE UNSETTLED CONDITIONS TUE-THU
THE REGIONAL PATTERN ALOFT WILL FEATURE INCREASING TROUGHINESS
THROUGH THE MEDIUM RANGE PERIOD...WITH THE GLOBAL ENSEMBLE MEANS
SHOWING A CORE OF NEGATIVE HEIGHT ANOMALIES OVER THE UPPER MIDWEST
AND GREAT LAKES REGIONS BY THE MIDDLE TO LATER PART OF NEXT WEEK
/SEPT 11-12TH/. OVERALL...THE NAEFS/GEFS AND ECENS ALL SIGNAL A
TRANSITION TOWARD A HIGHER AMPLITUDE PATTERN PARTICULARLY ACROSS
SOUTH CENTRAL CANADA.
AN ELONGATED COLD FRONT TRAILING A RELATIVELY STRONG SFC LOW OVER
NEWFOUNDLAND/LABRADOR WILL BE PASSING SOUTH OF PA SAT NIGHT. A
MODIFIED CANADIAN HIGH BUILDING SWD INTO THE CENTRAL PLAINS WILL
EVENTUALLY SHIFT EWD THROUGH THE NORTHEAST STATES AND MOVE INTO
THE MARITIMES BY NEXT WED.
SHRA/TSRA WILL END FROM NW-SE SAT NGT WITH MUCH DRIER AIR
FILTERING IN FOR SUNDAY. DRY WX SHOULD CONTINUE INTO EARLY NEXT
WEEK BEFORE CONDS TURN MORE UNSETTLED. EASTERLY WINDS TO THE SOUTH
OF HP CELL MOVG INTO THE MARITIMES ARE SUGGESTIVE OF A COOL-AIR
WEDGE OVER THE MID-ATLC WHICH SHOULD DAYTIME HIGHS NEAR AVG.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
MID DECK SLIDING INTO THE NW HAS AIDED IN LIFTING OF MORE DENSE
FOG AT KBFD...BUT THICKER FOG DEVELOPED ACROSS PORTIONS OF CENTRAL
AND SOUTHERN MTNS AROUND SUNRISE WITH VARIABLE MVFR TO IFR
CONDITIONS. THICKEST FOG WILL DISSIPATE RATHER QUICKLY /BY 13Z/
BUT MVFR CONDITIONS COULD LINGER INTO THE MID/LATE MORNING IN SOME
LOCATIONS.
ONCE MORNING FOG MIXES OUT...VSBYS WILL RANGE FROM 5-10SM WITH VFR
CIGS. FOCUS THEN SHIFTS TOWARD POTENTIAL FOR SCT DIURNAL
CONVECTION ACROSS SOUTHEAST PA. PWATS ARE PROJECTED TO APPROACH 2
INCHES IN THIS AREA AND HEATING OF THIS MOIST/UNSTABLE AIR MASS
SHOULD RESULT IN MODERATE CAPES OF ARND 2000J/JG ACROSS THE LOWER
SUSQ VALLEY BASED ON LATEST OPER MODEL AND GEFS OUTPUT. SCT PULSE-
TYPE TSRA SHOULD DEVELOP ACROSS THE SOUTHERN COUNTIES BRINGING
LOCAL RESTRICTIONS AS CONVECTIVE TEMP IS REACHED DURING THE
AFTN...AND ANY STORMS WILL BE SLOW- MOVERS DUE TO WEAK FLOW ALOFT.
HIGH DEWPOINTS REMAIN IN PLACE TONIGHT AHEAD OF AN APPROACHING
COLD FRONT. THIS WILL LEAD TO REDEVELOPMENT OF FOG/HAZE...AND AN
ENCROACHING MVFR CLOUD DECK ALONG WITH A CHANCE FOR SHOWERS AFTER
06Z IN THE NW.
OUTLOOK...
SAT...AM SHRA/LOW CIGS POSS NW MTNS. PM TSRA IMPACTS POSS
ELSEWHERE.
SUN...AM FOG POSS NW MTNS.
MON...PATCHY AM VALLEY FOG POSS.
TUE...CHC SHOWERS/TSTMS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD/STEINBUGL
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1030 AM CDT FRI SEP 5 2014
.DISCUSSION...
AN UPPER AIR ANALYSIS SHOWED A HIGH PRESSURE RIDGE EXTENDING FROM
THE MID ATLANTIC INTO THE LOWER TEXAS COAST. THE WATER VAPOR ALSO
SHOWED AN UPPER LOW OVER SOUTHERN LA DRIFTING WESTWARD..ALTHOUGH
THERE WAS ANOTHER UPPER LEVEL HIGH PRESSURE AREA OVER AR DRIFTING
SOUTHWESTWARD. THE 12Z SOUNDINGS SHOWED AN UNCAPPED AIRMASS WITH
PW/S FROM 1.8 TO 2 INCHES...ALTHOUGH DRIER AIR ASSOCIATED WITH
THE HIGH OVER AR WAS WORKING ITS WAY INTO THE AREA FROM THE
NORTHEAST. THIS SHOULD BE OFFSET LATER TODAY BY THE MOIST AIRMASS
OVER SOUTHERN LA WORKING ITS WAY WESTWARD. CAPE VALUES AT KLCH AND
KCRP RANGED FROM 3000 TO 3500...WHILE THE DRIER AIRMASS AT KSHV
HAD A CAPE OF 1600. ISOLATED STRONG STORMS ARE POSSIBLE WITH THE
MAIN THREAT STRONG WINDS AND LOCALLY HEAVY DOWNPOURS. OF THE HIGH
RESOLUTION MODELS...THE ARW INITIALIZED FAIRLY WELL. A CONSENSUS
OF THE ARW AND HRRR INDICATES SCATTERED COVERAGE OVER MOST OF THE
INLAND AREAS LATER TODAY.
TWEAKED THE RAIN CHANCES AND HUMIDITY GRIDS TODAY. ALSO UPDATED
THE HAZARDOUS WEATHER OUTLOOK TO INCLUDE THE POTENTIAL FOR
ISOLATED STRONG STORMS TODAY...SATURDAY...AND SUNDAY.
40
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 95 74 95 74 94 / 30 10 40 20 30
HOUSTON (IAH) 93 75 92 75 93 / 30 10 40 20 30
GALVESTON (GLS) 90 81 90 80 89 / 40 10 30 20 30
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...40
AVIATION/MARINE...47
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
845 AM CDT FRI SEP 5 2014
.UPDATED...
845 AM CDT FRI SEP 5 2014
WEAK UPPER LEVEL SHORTWAVE TROUGH IS WORKING ON THE EDGE OF THE
ELEVATED INSTABILITY RIDGE AND SOME WEAK SLOPING FROTOGENETIC
FORCING TO FIRE AREAS OF SHOWERS - PERHAPS A FEW THUNDERSTORMS -
ACROSS NORTHEAST IA THIS MORNING. MESO MODELS IN FAIRLY GOOD
AGREEMENT IN TRACKING THIS NORTHEAST THROUGH THE MORNING
HOURS...WITH A DECREASING TREND BY 18Z. THE PCPN IS COMING OUT OF
MID CLOUDS...AND ACCUMULATIONS WILL BE MINIMAL.
MEANWHILE...ANOTHER SHORTWAVE LOOKS TO TAKE AIM ON THE FORECAST AREA
BY MID/LATE AFTERNOON...SPINNING OUT OF THE CENTRAL PLAINS. HERE
AGAIN...MESO MODELS IN DECENT AGREEMENT IN HAVING THIS FEATURE SPIT
OUT A FEW SHOWERS - PERHAPS SOME THUNDER.
SO...HAVE INCREASED THE RAIN CHANCES ACROSS THE SOUTH FOR THIS
MORNING...AND AGAIN FOR LATER THIS AFTERNOON. THESE LATE AFTERNOON
CHANCES MAY HAVE TO BE INCREASED EVEN MORE...AND CARRIED INTO THE
EARLY EVENING. EXPECT SOME BREAK FOR THE EARLY PART OF THE
AFTERNOON.
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 320 AM CDT FRI SEP 5 2014
THE MAIN FOCUS IN THE SHORT TERM IS ON THE PRECIPITATION/TEMPERATURE/DEW
POINT TRENDS AS A COLD FRONT MOVES THROUGH THE REGION.
CURRENTLY...A SURFACE COLD FRONT EXTENDS FROM THE WESTERN UP OF
MICHIGAN DOWN THROUGH SOUTHWEST WISCONSIN AND SOUTH CENTRAL IOWA.
THE AIR MASS BEHIND THIS FRONT IS MUCH COOLER AND LESS HUMID WITH
TEMPERATURES DROPPING FROM THE UPPER 70S TO THE MID 50S AND DEW
POINTS GOING FROM THE MID 70S TO THE UPPER 40S. WHILE THE
ENVIRONMENT IN THE WARM SECTOR IS CAPPED OFF...SOME SLOPING LOW
LEVEL FRONTOGENESIS IS BEING AIDED BY A MID LEVEL TROUGH DIGGING
ACROSS NORTH DAKOTA/NORTHERN MINNESOTA AND HAS PRODUCED A BAND OF
CONVECTION ACROSS THE NORTHERN HALF OF IOWA. THIS RAIN WILL TRACK
TO THE NORTHEAST/EAST THIS MORNING BUT LIKELY WEAKEN AS IT LEAVES
THE DEEPER FORCING IN CENTRAL IOWA. THE 05.07Z RAP SHOWS THAT THE
0-3KM MUCAPE DROPS QUITE A BIT ONCE YOU REACH THIS
PRECIPITATION AND VERTICAL SHEAR PROFILES SHOW ONLY ABOUT 20-30KTS
OF 0-6KM SHEAR WITH MUCH OF IT AROUND 900-750MB. BASED ON
THIS...AM NOT EXPECTING MUCH IN THE WAY OF SEVERE WEATHER BUT
THAT THERE WILL BE A PERIOD OF LIGHT TO MODERATE
RAINFALL...PARTICULARLY ACROSS NORTHEAST IOWA AND FAR SOUTHWEST
WISCONSIN.
CLOUD COVER WILL LIKELY LINGER THROUGH MUCH OF THE DAY AS ANOTHER
MID LEVEL SHORT WAVE TROUGH TRACKS TO THE EAST FROM EASTERN
COLORADO/WESTERN NEBRASKA ON THROUGH IOWA TODAY. 06.00Z NAM/GFS
FORECAST SOUNDINGS SHOW A SATURATING MID LEVEL LAYER WITH DRY AIR
STUCK UNDERNEATH IT. WHILE THE FOCUS APPEARS TO MAINLY BE ACROSS
THE SOUTHERN HALF OF IOWA INTO TONIGHT...THE 05.00Z NAM/GFS/ECMWF
DO HINT AT SOME LIGHT QPF MAKING IT INTO THE REGION. CONFIDENCE IS
NOT HIGH ENOUGH RIGHT NOW WITH WHAT WILL WIN OUT IN THIS BATTLE OF
DRY AIR...SO HAVE KEPT THE FORECAST DRY INTO TONIGHT FOR THE TIME
BEING.
OTHERWISE...HIGH TEMPERATURES HAVE ALREADY BEEN HIT FOR THE DAY AS
THEY WILL DROP INTO THIS MORNING AND THEN MAKE A SMALL DIURNAL
BUMP THIS AFTERNOON BEFORE DROPPING QUICKLY TONIGHT. LOW LEVEL
WINDS LOOK LIKE THEY SHOULD BE STRONG ENOUGH TO KEEP ANY VALLEY
FOG FROM FORMING...BUT WILL HAVE TO MONITOR THE CONDITIONS INTO
TONIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 320 AM CDT FRI SEP 5 2014
FAIRLY QUIET EXTENDED PERIOD WITH THE COOLER TEMPERATURES THE MAIN
STORY. THE COOLEST PERIOD APPEARS TO BE THIS WEEKEND AS +6C TO +8C
850MB AIR SITS OVER THE REGION BEFORE WARMER AIR GETS ADVECTED IN
ON THE BACK SIDE OF THE RIDGE EARLY NEXT WEEK. THE NEXT CHANCES
FOR PRECIPITATION ARE ON MONDAY INTO THURSDAY AS A MID LEVEL
SHORT WAVE TROUGH MOVES THROUGH THE REGION. NOT MUCH INSTABILITY
TO WORK WITH AS THE 05.00Z GFS/ECMWF SHOW LESS THAN 1000 J/KG OF
0-3KM MUCAPE AROUND THE REGION SO DO NOT EXPECT MUCH IN THE WAY
OF WIDESPREAD THUNDERSTORMS...PARTICULARLY ANYTHING CONSIDERED
SEVERE.
A MORE SIGNIFICANT COLD PUSH LOOKS LIKE IT WILL MOVE IN ON
THURSDAY WITH 850MB TEMPERATURES DROPPING BELOW 0C. THIS WILL
LIKELY LEAD TO SOME LOW TEMPERATURES DIPPING INTO THE 30S GOING
INTO FRIDAY MORNING AND THE POTENTIAL FOR SOME FROST IN THE
TYPICAL LOW/COLD BOG AREAS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 625 AM CDT FRI SEP 5 2014
A COOLER/DRIER AIRMASS WAS SPREADING ACROSS THE TAF SITES THIS
MORNING...IN THE WAKE OF THE COLD FRONT THAT WAS ALREADY INTO
SOUTHEAST WI/IA. GENERALLY GOOD VFR CONDITIONS EXPECTED AT THE TAF
SITES TODAY/TONIGHT AS CANADIAN HIGH PRESSURE BUILDS INTO THE UPPER
MIDWEST. SOME MOISTURE LIFTING NORTHWARD OVER THE FRONTAL BOUNDARY
MAY SPREAD SOME -SHRA INTO THE KLSE AREA THRU THE MORNING. THIS
FORCING EXPECTED TO SLOWLY SHIFT SOUTH THRU THE MORNING AND LEFT THE
VCSH/-SHRA MENTION OUT OF THE KLSE TAF AT THIS TIME.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATED......RIECK
SHORT TERM...HALBACH
LONG TERM....HALBACH
AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
625 AM CDT FRI SEP 5 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 320 AM CDT FRI SEP 5 2014
THE MAIN FOCUS IN THE SHORT TERM IS ON THE PRECIPITATION/TEMPERATURE/DEW
POINT TRENDS AS A COLD FRONT MOVES THROUGH THE REGION.
CURRENTLY...A SURFACE COLD FRONT EXTENDS FROM THE WESTERN UP OF
MICHIGAN DOWN THROUGH SOUTHWEST WISCONSIN AND SOUTH CENTRAL IOWA.
THE AIR MASS BEHIND THIS FRONT IS MUCH COOLER AND LESS HUMID WITH
TEMPERATURES DROPPING FROM THE UPPER 70S TO THE MID 50S AND DEW
POINTS GOING FROM THE MID 70S TO THE UPPER 40S. WHILE THE
ENVIRONMENT IN THE WARM SECTOR IS CAPPED OFF...SOME SLOPING LOW
LEVEL FRONTOGENESIS IS BEING AIDED BY A MID LEVEL TROUGH DIGGING
ACROSS NORTH DAKOTA/NORTHERN MINNESOTA AND HAS PRODUCED A BAND OF
CONVECTION ACROSS THE NORTHERN HALF OF IOWA. THIS RAIN WILL TRACK
TO THE NORTHEAST/EAST THIS MORNING BUT LIKELY WEAKEN AS IT LEAVES
THE DEEPER FORCING IN CENTRAL IOWA. THE 05.07Z RAP SHOWS THAT THE
0-3KM MUCAPE DROPS QUITE A BIT ONCE YOU REACH THIS
PRECIPITATION AND VERTICAL SHEAR PROFILES SHOW ONLY ABOUT 20-30KTS
OF 0-6KM SHEAR WITH MUCH OF IT AROUND 900-750MB. BASED ON
THIS...AM NOT EXPECTING MUCH IN THE WAY OF SEVERE WEATHER BUT
THAT THERE WILL BE A PERIOD OF LIGHT TO MODERATE
RAINFALL...PARTICULARLY ACROSS NORTHEAST IOWA AND FAR SOUTHWEST
WISCONSIN.
CLOUD COVER WILL LIKELY LINGER THROUGH MUCH OF THE DAY AS ANOTHER
MID LEVEL SHORT WAVE TROUGH TRACKS TO THE EAST FROM EASTERN
COLORADO/WESTERN NEBRASKA ON THROUGH IOWA TODAY. 06.00Z NAM/GFS
FORECAST SOUNDINGS SHOW A SATURATING MID LEVEL LAYER WITH DRY AIR
STUCK UNDERNEATH IT. WHILE THE FOCUS APPEARS TO MAINLY BE ACROSS
THE SOUTHERN HALF OF IOWA INTO TONIGHT...THE 05.00Z NAM/GFS/ECMWF
DO HINT AT SOME LIGHT QPF MAKING IT INTO THE REGION. CONFIDENCE IS
NOT HIGH ENOUGH RIGHT NOW WITH WHAT WILL WIN OUT IN THIS BATTLE OF
DRY AIR...SO HAVE KEPT THE FORECAST DRY INTO TONIGHT FOR THE TIME
BEING.
OTHERWISE...HIGH TEMPERATURES HAVE ALREADY BEEN HIT FOR THE DAY AS
THEY WILL DROP INTO THIS MORNING AND THEN MAKE A SMALL DIURNAL
BUMP THIS AFTERNOON BEFORE DROPPING QUICKLY TONIGHT. LOW LEVEL
WINDS LOOK LIKE THEY SHOULD BE STRONG ENOUGH TO KEEP ANY VALLEY
FOG FROM FORMING...BUT WILL HAVE TO MONITOR THE CONDITIONS INTO
TONIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 320 AM CDT FRI SEP 5 2014
FAIRLY QUIET EXTENDED PERIOD WITH THE COOLER TEMPERATURES THE MAIN
STORY. THE COOLEST PERIOD APPEARS TO BE THIS WEEKEND AS +6C TO +8C
850MB AIR SITS OVER THE REGION BEFORE WARMER AIR GETS ADVECTED IN
ON THE BACK SIDE OF THE RIDGE EARLY NEXT WEEK. THE NEXT CHANCES
FOR PRECIPITATION ARE ON MONDAY INTO THURSDAY AS A MID LEVEL
SHORT WAVE TROUGH MOVES THROUGH THE REGION. NOT MUCH INSTABILITY
TO WORK WITH AS THE 05.00Z GFS/ECMWF SHOW LESS THAN 1000 J/KG OF
0-3KM MUCAPE AROUND THE REGION SO DO NOT EXPECT MUCH IN THE WAY
OF WIDESPREAD THUNDERSTORMS...PARTICULARLY ANYTHING CONSIDERED
SEVERE.
A MORE SIGNIFICANT COLD PUSH LOOKS LIKE IT WILL MOVE IN ON
THURSDAY WITH 850MB TEMPERATURES DROPPING BELOW 0C. THIS WILL
LIKELY LEAD TO SOME LOW TEMPERATURES DIPPING INTO THE 30S GOING
INTO FRIDAY MORNING AND THE POTENTIAL FOR SOME FROST IN THE
TYPICAL LOW/COLD BOG AREAS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 625 AM CDT FRI SEP 5 2014
A COOLER/DRIER AIRMASS WAS SPREADING ACROSS THE TAF SITES THIS
MORNING...IN THE WAKE OF THE COLD FRONT THAT WAS ALREADY INTO
SOUTHEAST WI/IA. GENERALLY GOOD VFR CONDITIONS EXPECTED AT THE TAF
SITES TODAY/TONIGHT AS CANADIAN HIGH PRESSURE BUILDS INTO THE UPPER
MIDWEST. SOME MOISTURE LIFTING NORTHWARD OVER THE FRONTAL BOUNDARY
MAY SPREAD SOME -SHRA INTO THE KLSE AREA THRU THE MORNING. THIS
FORCING EXPECTED TO SLOWLY SHIFT SOUTH THRU THE MORNING AND LEFT THE
VCSH/-SHRA MENTION OUT OF THE KLSE TAF AT THIS TIME.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM....HALBACH
AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
455 AM MDT FRI SEP 5 2014
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 231 AM MDT FRI SEP 5 2014
A COUPLE BANDS OF SHOWERS MOVING ACROSS PARTS OF THE CWA EARLY
THIS MORNING LIKELY AIDED BY AN UPPER JET MOVING NORTHEAST ACROSS
THE REGION. EXPECT THIS ACTIVITY TO MOVE OUT OVER THE NEXT SEVERAL
HOURS BEFORE REGENERATING OVER THE MTNS THIS AFTERNOON AS A WEAK
IMPULSE IN WESTERLY UPPER FLOW INTERACTS WITH SOME WEAK
INSTABILITY AND SOME UPSLOPE COMPONENT IN THE SFC WIND FLOW.
ACTIVITY WILL HAVE DIFFICULTY MAKING MUCH PROGRESS EASTWARD WITH
CAPPING OVER THE PLAINS. RATHER COOL OVER THE EASTERN PLAINS OF
THE CWA TODAY WITH MOST AREAS LIKELY STAYING IN THE 60S AS A SFC
HIGH SETTLES ACROSS THE CENTRAL PLAINS. COOL TONIGHT WITH SHOWERS
ENDING IN THE EVENING THEN BASICALLY A REPEAT PERFORMANCE SATURDAY
WITH SHOWERS AND A FEW STORMS DEVELOPING OVER THE MTNS IN THE
AFTERNOON BUT AGAIN NOT MAKING A LOT OF PROGRESS EASTWARD. ABOUT 5
TO 10 DEGREES WARMER SATURDAY WITH RETURN FLOW ON BACK SIDE OF
DEPARTING SFC HIGH. ADD ABOUT ANOTHER 5 TO 10 DEGREES FOR MAXS
SUNDAY WITH MORE OF A DOWNSLOPE FLOW AND SOME SUNSHINE. WIDELY
SCTD SHOWERS AND A FEW STORMS ONCE AGAIN INITIATING OVER THE MTNS
BUT MAKING A BIT BETTER PROGRESS OVER THE PLAINS.
.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 231 AM MDT FRI SEP 5 2014
MODEL CONSENSUS STILL POOR ON THE SYSTEM MIDWEEK. HUGE TEMPERATURE
BUST POTENTIAL WEDNESDAY AND THURSDAY DEPENDING ON WHICH MEDIUM
RANGE MODEL WINS OUT. FORECAST CHALLENGES IN THE EXTENDED DEAL
WITH MAINLY TEMPERATURES.
NORTHWEST FLOW FOR SUNDAY NIGHT WITH A WEAK SHORTWAVE MOVING
THROUGH NORTHERN WYOMING. HAVE SOME SLIGHT CHANCE POPS FOR THE
AREA SUNDAY NIGHT...MORE BASED ON WHAT THE GFS IS SHOWING. BUT
THEY SHOULD END FAIRLY QUICKLY AFTER MIDNIGHT. MONDAY LOOKS DRY
WITH GUIDANCE SHOWING MOST ALL OF THE QPF OVER COLORADO. DID KEEP
SOME LOW END CHANCE POPS FOR THE SNOWY AND SIERRA MADRE RANGES.
PRECIP REALLY DOES NOT GET INTO THE CHEYENNE CWFA UNTIL TUESDAY
AFTERNOON. BOTH THE GFS AND ECMWF HAVE POPS OUT IN CARBON COUNTY.
THIS IS WHERE MODEL GUIDANCE BEGINS TO DIVERGE.
GFS KEEPS 7000MB TEMPERATURES FAIRLY WARM TUESDAY NIGHT INTO
WEDNESDAY. TEMPERATURES STAY ABOVE FREEZING THROUGH WEDNESDAY
AFTERNOON. THE GFS DOES BRING A FRONT INTO THE AREA FROM THE
NORTH. 700MB TEMPERATURES FROM THE GFS RANGE FROM +6C TO +2C OVER
THE CWFA WEDNESDAY AFTERNOON. ECMWF ON THE OTHER HAND...HAS 700MB
TEMPERATURES OF +2C TO -2C OVER THE CWFA WEDNESDAY AFTERNOON.
WHILE THE ECMWF FORECASTS 700MB TEMPERATURES FALLING TO -6 TO -8C
THURSDAY NIGHT INTO FRIDAY...THE GFS KEEPS THE COLDER AIR NORTH
AND IS FORECASTING +10 TO +4C GRADIENT OVER WYOMING THROUGH FRIDAY
MORNING. DECIDED TO BEGIN GOING WITH THE MORE CONSISTENT
ECMWF...WHICH HAS BEEN SHOWING THIS COOL DOWN FOR THE PAST THREE
DAYS. USED HPC AND ECMWF GUIDANCE ON TEMPERATURES FOR THURSDAY AND
FRIDAY. WITH THIS FORECAST...THERE ARE GOING TO BE AREAS THAT WILL
MOST LIKELY SEE SNOW...ESPECIALLY CONVERSE/NIOBRARA COUNTIES IN
CENTRAL WYOMING. MAY STILL BE TOO WARM FOR SNOW IN THE NORTHERN
PANHANDLE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 453 AM MDT FRI SEP 5 2014
CEILINGS ARE STARTING TO COME DOWN NOW AS OF 11Z. HRRR SHOWING THE
SOUTHERN PANHANDLE...KCYS AND POSSIBLY KLAR COMING DOWN TO IFR
SHORTLY AFTER 12Z AND STAYING DOWN THROUGH AT LEAST 18Z. GENERALLY
FOLLOWED THE HRRR GUIDANCE ON FORECAST CONDITIONS THIS MORNING.
LOOKS LIKE A RETURN TO IFR THIS EVENING WITH UPSLOPING SOUTHEAST
WINDS.
&&
.FIRE WEATHER...
ISSUED AT 231 AM MDT FRI SEP 5 2014
FIRE WEATHER CONCERNS TO REMAIN LOW THROUGH THE WEEKEND WITH NON-
CRITICAL CONDITIONS EXPECTED WEATHER-WISE. SOMEWHAT COOL
CONDITIONS TODAY THEN A WARM UP OVER THE WEEKEND WITH DECREASING
CHANCES FOR RAIN.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...RE
LONG TERM...CLAYCOMB
AVIATION...CLAYCOMB
FIRE WEATHER...RE
AREA FORECAST DISCUSSION
NWS ALBANY NY
342 PM EDT FRI SEP 5 2014
.SYNOPSIS...
A FLOW OF WARM AND HUMID SOUTHERLY AIR WILL CONTINUE TO RESULT IN
ABOVE NORMAL TEMPERATURES INTO SATURDAY. A COLD FRONT APPROACHING
FROM THE GREAT LAKES AND SOUTHEAST CANADA WILL CROSS OUR REGION ON
SATURDAY...BRINGING SHOWERS AND THUNDERSTORMS. SOME OF THE
THUNDERSTORMS MAY BE STRONG TO SEVERE. MUCH COOLER AND DRIER AIR
WILL MOVE IN FOR SUNDAY AND MONDAY...AS HIGH PRESSURE BUILDS IN FROM
THE WEST.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 342 PM EDT...A VERY WARM AND HUMID AFTERNOON WILL GIVE WAY
TO A MUGGY NIGHT...AS OUR REGION REMAINS FIRMLY ENTRENCHED IN A
WARM SECTOR AHEAD OF A COLD FRONT APPROACHING FROM THE GREAT
LAKES. A FEW SHOWERS HAVE POPPED UP NEAR KPOU...SO WILL MENTION
ISOLATED POPS FOR A FEW HOURS EARLY THIS EVENING. OTHERWISE DRY
CONDITIONS WILL PERSIST.
MESOSCALE MODELS SUCH AS THE HRRR AND LOCAL HI RES WRF INDICATING
LINES/CLUSTERS OF CONVECTION WILL DEVELOP AHEAD OF AND ALONG THE
COLD FRONT OVER THE NIAGARA FRONTIER THIS EVENING. AS THIS ACTIVITY
APPROACHES CENTRAL NY LATER THIS EVENING IT IS FORECAST TO WEAKEN IN
INTENSITY...AND BY THE TIME IT POTENTIALLY REACHES EAST CENTRAL NEW
YORK LATE TONIGHT CONVECTION SHOULD DISSIPATE AS IT OUTRUNS THE
FORCING ASSOCIATED WITH THE FRONT. SO WILL ONLY MENTION SLIGHT
CHANCE TO LOW CHANCE POPS THROUGH THE NIGHT WEST OF THE CAPITAL
REGION...WITH THE HIGHER VALUES ACROSS THE WESTERN ADIRONDACKS AND
MOHAWK VALLEY. HIGHEST CONFIDENCE FOR AREAS FROM THE CAPITAL REGION
EASTWARD REMAINING RAIN-FREE THROUGH SUNRISE SATURDAY.
MINIMUM TEMPERATURES ONLY EXPECTED TO DROP INTO THE 60S REGION-WIDE.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
SATURDAY LOOKS TO BE A CONVECTIVELY ACTIVE DAY ACROSS MUCH OF THE
AREA...AS A COLD FRONT SWEEPS FROM NORTHWEST TO SOUTHEAST DURING THE
DAY. IT WILL REMAIN QUITE HUMID...SO ANY BREAKS OF SUNSHINE EARLY
WILL LEAD TO RAPID DESTABILIZATION AHEAD OF THE COLD FRONT. THE BEST
CHANCE FOR SOME EARLY SUNSHINE WHERE FORECAST SBCAPE VALUES COULD
REACH 1500-2500 J/KG...IS FROM AROUND THE ALBANY AND SARATOGA
REGIONS SOUTH AND EAST. FLOW ALOFT WILL STEADILY INCREASE THROUGH
THE AFTERNOON...WHICH WILL ALLOW THE SHEAR TO STRENGTHEN AS WELL.
DEEP LAYER SHEAR OF 25-35 KT AND THE APPROACHING COLD FRONT WILL
LIKELY ALLOW FOR ORGANIZED CLUSTERS/BOWS TO DEVELOP...WITH DAMAGING
WINDS THE MAIN THREAT AS FAIRLY WEAK MID-LEVEL LAPSE RATES SHOULD
PRECLUDE A HAIL THREAT. EFFICIENT DOWNPOURS WILL ALSO BE POSSIBLE
WITH ANY STORMS. HOWEVER...GIVEN THE INCREASING FLOW AND RECENT DRY
GROUND CONDITIONS...WE ARE NOT EXPECTING HYDRO RELATED PROBLEMS
EXCEPT FOR ISOLATED MINOR URBAN/POOR DRAINAGE FLOODING POSSIBLE.
BASED ON TIMING FROM THE 12Z GUIDANCE SUITE AND LOCAL HI RES
WRF...TIMING FOR CONVECTION LOOKS TO BE LATE MORNING TO EARLY
AFTERNOON FOR AREAS NORTH AND WEST OF THE CAPITAL REGION...MID TO
LATE AFTERNOON FOR THE CAPITAL REGION...SARATOGA REGION...SOUTHERN
VERMONT AND THE CATSKILLS...AND LATE AFTERNOON TO EARLY EVENING FOR
THE MID HUDSON VALLEY...TACONICS AND BERKSHIRES/LITCHFIELD HILLS.
DUE TO THE TIMING...BEST CHANCES FOR SEVERE STORMS WILL BE FROM
CENTRAL MOHAWK VALLEY AND SARATOGA REGION SOUTH AND EAST. THIS
INCLUDES THE GREATER CAPITAL DISTRICT AND ALL POINTS SOUTH AND EAST.
WILL CONTINUE TO MENTION POTENTIAL FOR DAMAGING WINDS IN THE HWO FOR
THESE AREAS.
DUE TO THE COLD FRONT FRONT CROSSING THE REGION...MAXIMUM
TEMPERATURES WILL RANGE FROM LOWER TO MID 70S ACROSS THE
ADIRONDACKS...TO LOWER TO MID 80S FROM ALBANY SOUTH AND EAST. IT
WILL REMAIN HUMID FOR MUCH OF THE AREA FOR MOST OF THE DAY...WITH
DEWPOINTS SPIKING IN THE UPPER 60S TO LOWER 70S.
ANY LINES OF CONVECTION SHOULD BE EAST OF THE AREA BY DARK...WHICH
WILL END THE SEVERE THREAT. JUST A FEW LINGERING SHOWERS WILL BE
POSSIBLE FOR THE REST OF THE EVENING...ESPECIALLY ACROSS SOUTHERN
AREAS. COOLER AND DRIER AIR WILL FILTER INTO THE REGION OVERNIGHT
WITH A NORTHWEST BREEZE. TEMPERATURES WILL BE NOTICEABLY COOLER BY
EARLY SUNDAY MORNING.
DRY WEATHER AND SEASONABLY COOLER TEMPERATURES ALONG WITH PLENTY OF
SUNSHINE EXPECTED FOR SUNDAY AND MONDAY...AS HIGH PRESSURE BUILDS
EASTWARD AND SETTLES ACROSS THE NORTHEAST CONUS. HUMIDITY LEVELS
WILL BE QUITE COMFORTABLE...WITH COOL NIGHT TIME TEMPERATURES.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
MONDAY NIGHT INTO TUESDAY...MOST OF THE REGION WILL SEE TRANQUIL
CONDITIONS WITH AVERAGE TEMPERATURES ACROSS THE REGION. 05/12Z MODEL
AND NUMERICAL GUIDANCE DOES SHOW A WEAK LOW PRESSURE SYSTEM WITH
TROPICAL ORIGINS MOVING SLOWLY UP THE EAST COAST. MOST OF THE REGION
NORTH OF THE LOWER MID HUDSON VALLEY WILL BE FAR ENOUGH REMOVED FROM
THE TRACK OF THIS COASTAL LOW. THIS WILL BRING SCATTERED CLOUD COVER
TO THE REGION BUT MOST REGIONS WILL REMAIN DRY WITH THE EXCEPTION OF
ISOLATED POPS ACROSS OUR FAR SOUTHEASTERN AREAS CLOSER TO THE CENTER
OF THE COASTAL LOW PRESSURE SYSTEM. HIGH TEMPERATURES ON TUESDAY
WILL RANGE FROM THE UPPER 60S IN THE HIGH TERRAIN TO LOWER AND MID
70S ACROSS VALLEY LOCATIONS.
TUESDAY NIGHT THROUGH FRIDAY...OUR NEXT WEATHER SYSTEM WILL BE
MAKING ITS WAY INTO THE REGION. MOST 12Z MODELS SHOW HIGHER
PROBABILITIES OF PRECIPITATION AS WE GO FROM THURSDAY INTO THURSDAY
EVENING. AS AN UPPER LEVEL LOW MOVES EQUATORWARD OUT OF CANADA AS WE
GO INTO THE DAY ON WEDNESDAY...A SERIES OF WEAK LOW PRESSURE
IMPULSES MOVING NORTHEASTWARD AROUND A BROAD 500 HPA CIRCULATION
OVER THE UPPER MIDWEST WILL PROVIDE ISOLATED TO SCATTERED SHOWERS
OVER OUR REGION...MAINLY DIURNALLY DRIVEN AS TEMPERATURES BEGIN TO
RISE INTO THE MID AND UPPER 70S ON WEDNESDAY WITH DEWPOINT
TEMPERATURES ON THE RISE AS WELL WITH A SOUTHERLY FLOW. AS WE GO
INTO THE DAY ON THURSDAY...THIS IS WHERE GLOBAL MODELS AND
PROBABILISTIC GUIDANCE DIVERGE IN CONFIDENCE FROM EACH OTHER. MODELS
RANGE FROM A CONTINUATION ON IMPULSES WHERE A WEAK SURFACE LOW MAY
DEVELOP JUST EAST OF OUR REGION THURSDAY AFTERNOON TO A MORE POTENT
SURFACE LOW DEVELOPMENT NEAR THE OHIO VALLEY UNDER A FAVORABLE
POSITION WITHIN A 100 KT JET STREAK PUTTING OUR REGION IN THE WARM
SECTOR FROM AN APPROACHING COLD FRONT AS WE GO INTO THURSDAY
EVENING. THIS FORECAST WILL BE UPDATED AS WE GET CLOSER TO THE EVENT
AND AS CONFIDENCE INCREASES. HIGH TEMPERATURES ON THURSDAY WILL
REMAIN NEAR AVERAGE ON THURSDAY. AS WE APPROACH THE END OF THE WEEK
ON FRIDAY...TRANQUIL WEATHER LOOKS TO RETURN TO THE REGION WITH
TEMPERATURES SLIGHTLY BELOW AVERAGE WITH A WEST TO NORTHWESTERLY
FLOW BEHIND THE PASSING COLD FRONT.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
THE REGION IS IN THE WARM SECTOR OF AN APPROACHING LOW PRESSURE
SYSTEM. CUMULUS CLOUDS WILL DISSIPATE WITH THE LOSS OF HEATING.
TONIGHT INITIALLY CIRRUS THEN MID LEVEL CLOUDS WILL STREAM IN.
MVFR-IFR CONDITIONS ARE EXPECTED TO DEVELOP OVERNIGHT DUE TO FOG
AND STRATUS ESPECIALLY LATE. THE STRATUS WILL LIFT AS WE HEAD INTO
THE MID MORNING PERIOD....HOWEVER LOW LEVEL CLOUDS AHEAD OF THE
LOW PRESSURE SYSTEM COLD FRONT WILL BE OVERSPREADING THE REGION.
CHANCES FOR CONVECTION WILL BE IN THE INCREASE AS WE HEAD INTO
LATE MORNING/EARLY AFTERNOON. AT THIS TIME...HAVE INTRODUCE PROB30
FOR SHOWERS AT KGFL...KALB AND KPSF. THE THREAT EXPECTED TO HOLD
OFF UNTIL AFTER 18Z/SATURDAY AT KPOU. THERE WILL BE CHANCES FOR
STRONG TO SEVERE STORMS DURING THE AFTERNOON MAINLY AT KPSF AND
KPOU WHERE THE ATMOSPHERE WILL BE MORE UNSTABLE. MAIN THREAT OF
FOR STRONG TO DAMAGING WINDS GUSTS.
SOUTHERLY WINDS OF UP TO AROUND 10 KNOTS WITH SOME GUSTS POSSIBLE AT
KALB THIS AFTERNOON...WILL WEAKEN TONIGHT BUT REMAIN OUT OF THE
SOUTH. THE FLOW WILL SHIFT MORE TO THE SOUTH-SOUTHWEST SATURDAY AS
THE COLD FRONT INCREASING TO AROUND 10 KNOTS.
OUTLOOK...
SATURDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
SUNDAY TO MONDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
TUESDAY TO TUESDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE
OF SHRA.
WEDNESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
&&
.FIRE WEATHER...
A FLOW OF WARM AND HUMID SOUTHERLY AIR WILL CONTINUE TO RESULT IN
ABOVE NORMAL TEMPERATURES INTO SATURDAY. A COLD FRONT APPROACHING
FROM THE GREAT LAKES AND SOUTHEAST CANADA WILL CROSS OUR REGION ON
SATURDAY...BRINGING SHOWERS AND THUNDERSTORMS. SOME OF THE
THUNDERSTORMS MAY BE STRONG TO SEVERE. MUCH COOLER AND DRIER AIR
WILL MOVE IN FOR SUNDAY AND MONDAY...AS HIGH PRESSURE BUILDS IN FROM
THE WEST.
RELATIVE HUMIDITY VALUES WILL INCREASE TO AROUND 90 TO 100 PERCENT
TONIGHT...THEN DROP TO MINIMUM VALUES OF BETWEEN 55 AND 65 PERCENT
SATURDAY AFTERNOON. MAXIMUM RH VALUES SATURDAY NIGHT ARE EXPECTED TO
BE AROUND 90 TO 100 PERCENT.
WINDS TONIGHT ARE EXPECTED TO BE SOUTHERLY AROUND 5 TO 10 MPH.
SOUTHERLY WINDS WILL SHIFT TO THE WEST BEHIND A COLD FRONT SATURDAY
AFTERNOON. WINDS WILL BECOME NORTHWESTERLY AROUND 5 TO 10 MPH
SATURDAY NIGHT.
&&
.HYDROLOGY...
NO WIDESPREAD HYDRO PROBLEMS ARE EXPECTED THROUGH AT LEAST THE NEXT
5 DAYS.
SHOWERS AND THUNDERSTORMS WILL DEVELOP AND OVERSPREAD THE AREA FROM
NORTHWEST TO SOUTHEAST ON SATURDAY AHEAD OF A COLD FRONT. WHILE
BASIN AVERAGE RAINFALL AMOUNTS LOOK TO BE UNDER A HALF
INCH...LOCALIZED RAINFALL AMOUNTS OF OVER 2 INCHES ARE POSSIBLE
WHICH MAY CAUSE ISOLATED MINOR FLOODING OF URBAN/POOR DRAINAGE
AREAS.
DRIER WEATHER IS THEN EXPECTED SATURDAY NIGHT THROUGH TUESDAY...AS
HIGH PRESSURE ASSOCIATED WITH RELATIVELY COOL AIR SETTLES OVER THE
REGION.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...JPV
NEAR TERM...JPV
SHORT TERM...JPV
LONG TERM...IAA/LFM
AVIATION...IAA
FIRE WEATHER...JPV
HYDROLOGY...11/JPV
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1142 AM CDT FRI SEP 5 2014
.DISCUSSION...
1142 AM CDT
COLD FRONT IS MOVING THROUGH NORTHWESTERN PORTIONS OF THE CWA LATE
THIS MORNING AND SHOULD CONTINUE TO MAKE STEADY PROGRESS SOUTHEAST
ACROSS THE AREA THIS AFTERNOON. DEVELOPING PRESSURE FALLS OVER
IOWA IN ADVANCE OF SHORTWAVE TROUGH OVER NE KS/SE NE WILL PROBABLY
RESULT IN FRONT SLOWING DOWN A BIT THIS AFTERNOON. GOES EAST IS IN
RAPID SCAN MODE THIS AFTERNOON AND IS NICELY SHOWING SOME
ENHANCEMENT TO THE CUMULUS FIELD RIGHT ALONG THE IMMEDIATE FRONTAL
BOUNDARY. IN GENERAL THE CUMULUS FIELD ON SATELLITE AND OUT THE
WINDOW LOOKS VERY MUSHY AND LACKING VERTICAL GROWTH...LIKELY DUE
IN LARGE PART TO THE VERY FORMIDABLE CAP EVIDENT ON DVN/ILX MORNING
SOUNDINGS AND STILL PRESENT IN RECENT ACARS SOUNDINGS OUT OF ORD
AND MDW. CONTINUED HEATING AND DESTABILIZATION OF THE BOUNDARY
LAYER ALONG WITH FORCED ASCENT ALONG THE FRONT SHOULD EVENTUALLY
CAUSE CAP TO BUST...BUT LIKELY NOT UNTIL THE FRONT IS AT LEAST TO
A CHICAGO TO PERU LINE IF NOT FARTHER SOUTHEAST. WILL BE REWORKING
POP GRIDS TO BETTER REFLECT THIS LINE OF THINKING...INCLUDING VERY
LITTLE THREAT OF PRECIP OVER NORTHWEST CWA AND STEADILY DECREASING
CHANCE FROM THE NORTHWEST SPREADING ACROSS THE AREA THIS
AFTERNOON. POST FRONT RAIN STILL A DISTINCT POSSIBILITY THIS
EVENING INTO TONIGHT AS AFOREMENTIONED KS/NE SHORTWAVE TRACKS
NORTHEAST INTO THE REGION.
IZZI
&&
.PREV DISCUSSION...
325 AM CDT
THE EMPHASIS OF THE FORECAST WAS SPENT ON THE FIRST 24 HOURS
WHICH PRESENT THUNDERSTORMS IN THE REGION TODAY...INCLUDING THE
POTENTIAL FOR SOME SEVERE STORMS THIS AFTERNOON...AND THEN RAIN
CHANCES THROUGH TONIGHT.
TODAY...
A VERY MILD...MUGGY...AND EVEN BREEZY EARLY MORNING ACROSS THE AREA
WITH SOME PARTS OF CHICAGO AT 80 DEGREES AS OF 3 AM. AREA DEW POINTS
ARE IN THE MID 70S...MATCHING THAT OF THE GULF SEABOARD THIS
MORNING. THIS SURFACE WARM SECTOR IN PLACE IS ASSOCIATED WITH A
1000MB LOW PRESSURE DEPARTING NORTHEASTWARD WITH ITS PARENT UPPER
TROUGH ACROSS ONTARIO THIS MORNING. THE ELONGATED SYSTEM COLD
FRONT WILL OOZE SOUTHEASTWARD REACHING NORTH CENTRAL IL DURING
MID-MORNING AND THE CHICAGO AREA AROUND NOONTIME...WHILE CLEARING
THE SOUTHEAST FORECAST AREA BY EARLY THIS EVENING.
WHILE THE REGIONAL RADAR THIS MORNING DOES SHOW A DECENT AMOUNT OF
CONVECTION IN IA AND EASTERN NE...MUCH OF THAT IS POST FRONTAL. ANY
SHOWERS OR STORMS BEFORE NOON WOULD LIKELY BE DUE TO A SUBTLE
MOISTENING IN THE VERY UNSTABLE LAYER ALOFT...WHICH THERE IS A
LITTLE BIT OF ON IR/11-3.9 MICRON SATELLITE IMAGERY. THIS TYPE OF
FORCING WOULD INDICATE ONLY ISOLATED IN COVERAGE IF DEVELOPMENT
WERE TO OCCUR.
WITH SURFACE HEATING AND ADVECTION OF EVEN HIGHER 0-1KM MIXING
RATIOS AHEAD OF THE FRONT DURING THE AFTERNOON...ADAPTED MODEL
SOUNDINGS LEAD TO FAIRLY HIGH CONFIDENCE THAT THE CAP WILL BE
BREACHED WITH SCATTERED STORMS ALONG THE COLD FRONT. DEPENDING ON
THE DEGREE OF HEATING...THIS COULD OCCUR ALREADY BY 12-2 PM. THIS
IS MOST FAVORED ALONG AND EAST OF INTERSTATE 55. LOOKING AT
HIGH-RES CONVECTIVE MODELS IN AN ENSEMBLE APPROACH /SPC
SSEO/...THERE ARE GOOD NEIGHBORHOOD VALUES OF HIGHER UPDRAFT SPEED
SUPPORTED BY HIGH INSTABILITY WITH MLCAPE IN EXCESS OF 3000 J/KG.
WITH LAGGING UPPER/MID-LEVEL FLOW TO THE FRONT...INSTABILITY WILL
BE THE DRIVER OF THESE STORMS AND THEIR INITIAL EVOLUTION.
EXPECTING A MODE THUS OF SOMEWHAT SLOW-MOVING CELLS OR MULTI-
CELLS WHICH SHOULD EVOLVE SOUTHEASTWARD THROUGH LATE
AFTERNOON/EARLY EVENING. A SCATTERED LARGE HAIL AND LOCALIZED
FLASH FLOODING THREAT WILL EXIST...AND WITH ANY MULTI-CELLS AN
ISOLATED SEVERE WIND THREAT...WITH THE LATTER LOOKING BETTER
FURTHER EAST AS STORM ORGANIZATION IS MORE FAVORED.
TONIGHT...
WHILE THE SURFACE FRONT WILL HAVE CLEARED THE FORECAST AREA BY OR
DURING EARLY EVENING...A SECOND STRONG UPPER SHORT WAVE ACROSS CO
EARLY THIS MORNING WILL TRACK NORTHEASTWARD ALONG THE 700-500MB
BAROCLINIC ZONE. THIS HAS BEEN CONSISTENTLY FORECAST IN THE REGION MY
MODELS FOR DAYS AND NOW OBSERVATIONAL SATELLITE TRENDS ARE
SUPPORTING THIS. THIS IS AN EARLY SIGN OF THE COOL SEASON...AS THIS
TYPE OF FORCING BEGINS TO SHOW UP MORE AND WILL EVENTUALLY
REPLACE THE VERTICAL INSTABILITY THAT WE ARE LOOK AT TODAY. BUT
NO NEED TO RUSH INTO THAT! SO BACK TO TONIGHT...A VERTICAL
FRONTAL CIRCULATION IS FORECAST WHICH WITH MOISTURE TRANSPORT AND
SATURATION IN THE MID-LEVELS SHOULD AT LEAST ALLOW LIKELY RAIN
IN THE REGION. THERE IS UNCERTAINTY ON HOW FAR NORTH RAIN THIS WILL
BE. ITS CERTAINLY PLAUSIBLE THAT EVEN THE NORTHERN CWA GETS INTO
THIS...WITH ROCKFORD AND CHICAGO HAVING A FEW HOUR PERIOD OF LIGHT
RAIN THIS EVENING INTO EARLY OVERNIGHT. ELEVATED INSTABILITY WILL
BE SLOW TO DEPART IN THE SOUTHERN FORECAST AREA SO CONTINUE
THUNDER CHANCES WITH MORE OF A MODERATE RAIN THERE. ADDITIONAL
RAINFALL AMOUNTS TONIGHT OF OVER ONE HALF INCH ARE FAVORED UNDER
ANY MORE SUSTAINED RAIN CORRIDORS THAT SET UP.
THIS WEEKEND...
NO REAL CHANGES MADE TO THIS PORTION OF THE FORECAST. LINGERING
ANAFRONTAL CLOUDS COULD CONTINUE SATURDAY MORNING BUT A CLEAR SKY IS
EXPECTED FOR THE REST OF THE WEEKEND. AFTERNOON TEMPERATURES IN
THE LOWER TO MID 70S...ABOUT 5 TO 7 DEGREES BELOW NORMAL...ARE
FORECAST. SURFACE WINDS SHOULD BECOME CALM EACH LATE EVENING AND
WITH DRIER AIR ADVECTION CONTINUING...WE UNDERCUT A MODEL FORECAST
BLEND FOR LOWS. SHOULD SEE OUTLYING AREAS REALIZE LOWS IN THE
UPPER 40S WITH COOL SPOTS POSSIBLY MID 40S.
NEXT WEEK...
CONTINUED QUASI-ZONAL UPPER FLOW ACROSS THE NORTHERN U.S. AT THE
FAR SOUTHERN BASE OF A COLD CANADIAN TROUGH IS FORECAST NEXT WEEK.
RETURN LOW-LEVEL LOW RESUMES EARLY IN THE WORKWEEK...BUT
MOISTENING LOOKS SLOW. GIVEN THAT AND THE FACT ANY FORCING
MECHANISMS LOOK TO BE LOW AMPLITUDE...SPREAD POPS IN SLOWER THAN
GUIDANCE MONDAY NIGHT-TUESDAY NIGHT. NOT SURPRISING TO SEE A LARGE
MODEL SPREAD IN SPECIFICS DURING THE MIDDLE OF NEXT WEEK...BUT
RIGHT NOW SOMETIME IN THE WEDNESDAY-THURSDAY PERIOD A STRONGER
SHORT WAVE TROUGH IS FORECAST TO PASS...WHICH CONCEIVABLY WOULD
BRING THE GREATER RAIN CHANCES TO THE REGION.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* TIMING/COVERAGE OF TSRA TODAY.
* WIND SHIFT FROM SW TO NW WITH COLD FRONT THIS AFTN.
* POTENTIAL FOR MVFR CIGS THIS AFTN/TONIGHT.
RATZER/IZZI
//DISCUSSION...UPDATED 12Z...
COLD FRONT STRETCHES FROM EAST CENTRAL WI TO EASTERN IA THIS
MORNING. ISOLATED SHRA/TSRA POSSIBLE IN WARM/MOIST SOUTHWEST FLOW
AHEAD OF THE FRONT THIS MORNING...THOUGH LITTLE TO FOCUS
WIDESPREAD DEVELOPMENT EXPECTED UNTIL SURFACE COLD FRONT
APPROACHES AND TIMING OF COLD FROPA STILL APPEARS TO BE AROUND
15Z FOR KRFD AND 19-20Z FOR KORD/KMDW. THE GREATEST POTENTIAL FOR
TSRA WILL BE THIS AFTERNOON ALONG/AHEAD OF THE FRONT...WITH HIGH-
RES MODEL GUIDANCE INDICATING TSRA INITIATION NEAR OR SOUTHEAST OF
CHICAGO. TSRA THREAT SHOULD MOVE SOUTHEAST OF TERMINALS BY LATE
AFTERNOON AS THE FRONT CONTINUES TO PUSH SOUTHEAST. MVFR CIGS
POSSIBLE IN SHRA/TSRA...AND ALSO FOR A PERIOD BEHIND THE FRONT
THIS AFTERNOON. SHOWERS/RAIN EXPECTED TO REDEVELOP ACROSS THE
TERMINALS THIS EVENING WITH FURTHER MVFR CIG POTENTIAL AS AN
UPPER DISTURBANCE PROPAGATES ACROSS THE AREA. EXPECTATION IS FOR
CIGS TO BE IN 2000-3000 FT RANGE. DRIER AIR FINALLY MOVES IN EARLY
SATURDAY MORNING WITH VFR CONDITIONS.
SOUTHWEST WINDS AROUND 10 KT THIS MORNING AHEAD OF THE FRONT WILL
SHIFT MORE WEST-SOUTHWEST WITH TIME...THEN NORTHWEST BEHIND THE
FRONT. SOME GUIDANCE INDICATES WINDS MAY BECOME MORE NORTH OR EVEN
NORTH-NORTHEAST BRIEFLY THIS AFTERNOON...BUT LIKELY TO HOLD OFF
UNTIL LATE TONIGHT/SATURDAY.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* LOW-MEDIUM IN TSRA/MVFR CIGS.
* HIGH FOR WINDS AND OTHER FORECAST ELEMENTS.
RATZER/IZZI
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT THROUGH MONDAY...VFR. SLGT CHC TSRA MONDAY NIGHT.
TUESDAY AND WEDNESDAY...CHC OF PERIODIC TSRA. MVFR CIGS PSBL.
THURSDAY...CHC OF SHOWERS. MVFR CIGS PSBL.
RATZER
&&
.MARINE...
314 AM CDT
LOW PRESSURE WAS NORTH OF LAKE SUPERIOR EARLY THIS MORNING...WITH A
COLD FRONT TRAILING SOUTHWEST ACROSS WISCONSIN AND EASTERN IOWA.
THIS LOW WILL TRACK TO THE NORTHEAST WHILE CONTINUING TO DEEPEN
TODAY WHILE THE FRONT PUSHES SOUTHEAST ACROSS THE LAKE THROUGH THIS
AFTERNOON. SURFACE PRESSURE FALLS AND A RELATIVELY TIGHT PRESSURE
GRADIENT AHEAD OF THE FRONT AND ASSOCIATED WITH THE DEEPENING LOW
HAS LED TO SOUTH-SOUTHWEST WINDS IN THE 25-30 KT RANGE OVERNIGHT.
WINDS SHOULD GRADUALLY EASE INTO THE 15-25 KT RANGE AS THE GRADIENT
WEAKENS IN PROXIMITY TO THE COLD FRONTAL TROUGH LATER THIS MORNING
AND THIS AFTERNOON...VEERING TO THE NORTHWEST AND EVENTUALLY NORTH
BEHIND THE FRONT TONIGHT. SURFACE HIGH PRESSURE WILL THEN BUILD
SOUTHEAST ACROSS THE PLAINS...AND EAST ACROSS THE SOUTHERN GREAT
LAKES TONIGHT AND SATURDAY WHILE A SECOND WEAK COLD FRONT SETTLES
ACROSS THE NORTHERN LAKES. NORTH-NORTHWEST WINDS ARE EXPECTED TO
REMAIN IN THE 15-20 KT RANGE WITH A FEW GUSTS TO 25 KT POSSIBLE INTO
EARLY SATURDAY AS COOL AIR BUILDS IN WITH THE HIGH...THEN SLACKEN
SATURDAY NIGHT AND SUNDAY AS THE HIGH MOVES EAST ACROSS THE LAKES.
BY MONDAY THE HIGH WILL SHIFT OVER THE ST LAWRENCE VALLEY...WHILE
LOW PRESSURE DEVELOPS ACROSS THE NORTHERN PLAINS. THIS WILL ALLOW
WINDS TO SHIFT BACK TO THE SOUTH EARLY NEXT WEEK...WITH THE PLAINS
LOW EVENTUALLY APPROACHING THE GREAT LAKES MID-WEEK.
FOR THE ILLINOIS/NORTHWEST INDIANA NEARSHORE WATERS...SOME GUSTS
NEAR 30 KT NOTED FROM HIGH-MOUNTED WIND MEASURING EQUIPMENT THIS
MORNING BUT WITH RELATIVELY LOW WAVES IN OFFSHORE FLOW. NORTHERLY
FETCH LATER TONIGHT AND SATURDAY LOOKS TO PRODUCE MARGINAL SMALL
CRAFT ADVISORY CONDITIONS.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1053 AM CDT Fri Sep 5 2014
.UPDATE...
ISSUED AT 1047 AM CDT FRI SEP 5 2014
Cold front approaching the region and some scattered showers
popped up this morning on the nose of the llvl jet early...and
were gone. More showers and thunderstorms are possible into the
afternoon as the front approaches and just behind it. Until
then...hot and muggy conditions expected to continue with
southwesterly winds. Heat indices are expected to climb into the mid
90s and near 100 south of Interstate 70. Minor tweaks to the
forecast grids, but no major changes.
&&
.SHORT TERM...(Today)
ISSUED AT 328 AM CDT FRI SEP 5 2014
Cold front beginning to edge into east central Iowa early this
morning with most models pushing the boundary across our area during
the afternoon and early evening hours. One more hot and humid day
ahead of the cold front with temperatures ranging from the upper
80s far northwest to the lower 90s east central through southeast
Illinois. Forecast soundings showing the warm layer extending from
850-700 mb will gradually erode with time today which should allow
better coverage of convection along the frontal boundary despite
rather weak convergence. However, most models depict some robust
CAPES this afternoon with 3500-4500 J/KG forecast over central thru
east central Illinois. 0-6km bulk shear not very impressive until
you get behind the cold front, otherwise, most models indicate bulk
shear values of 15-20 kts in the warm section just ahead of the
front. Precipitable water values of around 2 inches still forecast
this afternoon so any storms that organize will produce torrential
rainfall in a short period of time, in addition to the possibility
for an isolated strong wind gust/wet microburst. Most of the
convective allowing models suggest the stronger convection will
begin to push into Indiana by late this afternoon or early this
evening and then begin to weaken.
&&
.LONG TERM...(Tonight through Friday)
ISSUED AT 328 AM CDT FRI SEP 5 2014
Cold front passes southeast of CWA this evening, while 00Z models
have trended slower with mid/upper level system/forcing tonight
into Saturday morning with showers and isolated thunderstorms likely
lingering overnight and over southern half from I-72 south Saturday
morning. Lows tonight to range from upper 50s and lower 60s over IL
river valley to upper 60s southeast of I-70 where muggy conditions
linger through tonight. North winds to advect in cooler and less
humid air during the day Saturday as clouds decrease from nw to se
Saturday afternoon. Much cooler highs in the mid 70s Saturday as
1022 mb high pressure over the northern Rockies settles east into
the central plains. This high pressure will settle over IL and
southern great lakes Sunday and keep cooler and less humid air in
place. Lows Saturday and Sunday night in low to mid 50s with a few
upper 40s over a few spots from I-74 ne. A fair amount of sunshine
Sunday with highs in the mid to upper 70s and comfortable dewpoints
in the low to mid 50s. Another nice day in store Monday as high
pressure settles into New England and clouds increase from the west
over IL ahead of next weather system. Highs in the upper 70s central
IL and near 80F south of I-70.
Unsettled weather pattern taking shape from Monday night through
Thu. Weather system spread qpf into IL from west to east during
Monday night into Tue and models have trended faster with this
feature so have increased pops. A stronger weather system arriving
Wed/Thu time frame as surface low pressure deepens ne from the
southern plains into the great lakes. Expect increased chances of
showers and a few thunderstorms. Then much cooler temperatures
arrive by next Friday and Friday night.
&&
.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
ISSUED AT 605 AM CDT FRI SEP 5 2014
A cold front over east central Iowa will push into our area early
this afternoon and bring the threat for scattered showers and
thunderstorms to central through east central Illinois into early
this evening. Other than some patchy fog early this morning which
may produce a brief period of MVFR vsbys, VFR conditions are expected
into this evening. Forecast soundings and time height cross sections
indicate that as the cooler air arrives later this evening, it may be
accompanied by some MVFR or possibly IFR cigs in the 08z-12z time
frame. Not seeing a lot of evidence of widespread MVFR or lower cigs
behind the cold front at this time, so will only introduce a scattered
cloud below 1000 feet late in the period with a prevailing cig above
that at 3500-4000 feet. Coverage of storms this afternoon near the
front scattered at best with the latest HRRR model suggesting areas
along and southeast of a Danville to Lincoln to Jacksonville line
having a better chance for seeing convection into early this evening.
For this reason, will continue with the tempo groups at KCMI, KDEC
and KSPI, with VCTS further north at KBMI and KPIA where it appears
coverage of storms will be less.
It appears there may be a break in the convection early this evening
with a round of showers moving in late tonight into Saturday morning
as a weak area of low pressure drifts east along the slow moving cold
front, which by this time, should be south of our area. Will carry
a VCSH for later this evening across most of our area and keep an eye
on the lowering cigs. Surface winds ahead of the front will be out
of the southwest at 10 to 15 kts, then become westerly along the
boundary, and with the FROPA, winds should shift to a northwest
to north direction by late afternoon and early evening with speeds
running from 8 to 13 kts.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HJS
SHORT TERM...SMITH
LONG TERM...07
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
216 PM EDT FRI SEP 5 2014
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 324 AM EDT FRI SEP 5 2014
VERY WARM HUMID CONDITIONS TODAY WILL COME TO AN ABRUPT END AS A
COLD FRONT TRACKS THROUGH THE REGION WITH SHOWERS AND THUNDERSTORMS
TONIGHT AND SATURDAY. HIGH PRESSURE WILL BUILD IN BEGINNING SATURDAY
NIGHT WITH DRY AND MUCH COOLER WEATHER INTO EARLY NEXT WEEK.
THUNDERSTORM CHANCES WILL RETURN TUESDAY AND CONTINUE THROUGH MUCH
OF NEXT WEEK AS A COLD FRONT MOVES THROUGH THE GREAT LAKES AND OHIO
VALLEY.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 955 AM EDT FRI SEP 5 2014
.UPDATE...CURRENT FORECAST IS ON TRACK AND ONLY MINOR CHANGES MADE
WITH THIS UPDATE...MAINLY TO RAISE POPS SLIGHTLY OVER FAR NORTHERN
SECTIONS AS SHOWERS AND THUNDERSTORMS WERE ALREADY OVER NORTHEAST
ILLINOIS WHICH MAY BRUSH FAR NORTHERN AREAS IN A FEW HOURS.
PORTION OF PREVIOUS NEAR TERM DISCUSSION FOLLOWS...
MOST CONVECTION HAS REMAINED WELL NORTH/NORTHWEST OF THE FORECAST
AREA ALONG A COLD FRONT. MOST INTENSE STORMS ACROSS THE NORTHERN
GREAT LAKES THIS MORNING IN VICINITY OF A STRONGER SURFACE WAVE AND
A SHARPENING UPPER TROUGH. THE UPPER RIDGE WILL BUCKLE IN RESPONSE
TO THE AMPLIFYING UPPER TROUGH OVER THE UPPER MISSISSIPPI VALLEY...
ENABLING THE FRONTAL BOUNDARY TO SAG INTO THE NORTHERN FORECAST AREA
BY THIS EVENING.
AHEAD OF THE FRONT...ABUNDANT SUNSHINE AND SOUTHWEST FLOW WILL
PROVIDE FOR ANOTHER VERY WARM HUMID DAY FOR CENTRAL INDIANA. MID
LEVEL HEIGHTS WILL BEGIN TO FALL BY THE AFTERNOON AS THE FRONT
APPROACHES FROM THE NORTH AND COMBINED WITH VERY WEAK UPPER FORCING
AND A STRONGLY UNSTABLE AIRMASS...WILL INTRODUCE LOW CHANCE POPS
GRADUALLY INCREASING FROM THE NORTHWEST INTO THE EVENING. BOTH THE
WRF AND HRRR THIS MORNING APPEAR OVERDONE WITH RESPECT TO CONVECTIVE
DEVELOPMENT IN THE AFTERNOON...BUT ISOLATED STORMS CERTAINLY CANNOT
BE RULED OUT WITH THE PARAMETERS ABOVE. A LINE OF MORE ROBUST
CONVECTION IS EXPECTED TO DEVELOP THIS AFTERNOON IN THE VICINITY OF
THE FRONT OVER THE LOWER GREAT LAKES. THESE STORMS WILL BE
APPROACHING THE FORECAST AREA FROM THE NORTHWEST BY 00Z.
TEMPS...WITH 850MB TEMPS AT 20-21C AND A SOUTHWEST FLOW THIS
AFTERNOON...HAVE TRENDED TOWARDS THE WARMER MAVMOS FOR HIGHS IN THE
UPPER 80S AND LOWER 90S. MAX HEAT INDICES OF 95 TO 100 DEGREES THIS
AFTERNOON ARE EXPECTED AS WELL AND WILL HIGHLIGHT IN THE HWO.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 324 AM EDT FRI SEP 5 2014
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES THROUGH LATE SATURDAY AS
THE FRONT MOVES THROUGH THE REGION. 00Z MODEL GUIDANCE HAS GENERALLY
SLOWED THE PASSAGE OF THE BOUNDARY WITH PRECIP CHANCES LINGERING
OVER MUCH OF THE SOUTHERN HALF OF THE FORECAST AREA FOR A GOOD
PORTION OF SATURDAY.
FIRST ISSUE IS WITH EXPECTED CONVECTION MOVING INTO THE FORECAST
AREA FROM THE NORTHWEST THIS EVENING. WHILE STRONGER MID/UPPER LEVEL
FORCING AND STRONGER BL SHEAR WILL REMAIN WELL NORTH OF THE
REGION...PRESENCE OF CONVECTION MOVING INTO A STRONGLY UNSTABLE
AIRMASS WITH HIGH PRECIP WATER VALUES SHOULD BE ABLE TO COMPENSATE
FOR STORM INTENSITY MAINTENANCE INTO THE FORECAST AREA THIS EVENING.
POTENTIAL FOR A FEW OF THESE STORMS TO BE SEVERE...ESPECIALLY IF
CONVECTION CAN LAY DOWN A COLD POOL AND PROVIDE FOR AN ENHANCED
DAMAGING WIND THREAT FOR A SHORT PERIOD OF TIME. AS INSTABILITY
WANES AND THE STORMS MOVE AWAY FROM THE LIMITED BL SHEAR...SHOULD
SEE STORMS WEAKEN AND DIMINISH IN COVERAGE BY LATE EVENING SOUTH OF
I-70. WILL CARRY LIKELY POPS NORTH OF I-70 WITH LOWER POPS FURTHER
SOUTH.
THE FRONT WILL CONTINUE ITS SLOW PROGRESS SOUTH THROUGH THE FORECAST
AREA SATURDAY. MID LEVEL DEFORMATION AXIS PASSING THROUGH THE LOWER
GREAT LAKES WITH THE UPPER TROUGH WILL LINGER PRECIP CHANCES OVER
THE REGION...BUT WITH AN ABUNDANCE OF CLOUDS AND LIMITED
INSTABILITY...HARD TO JUSTIFY MUCH MORE THAN AN ISOLATED THUNDER
THREAT WITH SHOWERS. SHOWERS WILL GRADUALLY SHIFT INTO SOUTHERN
COUNTIES DURING THE AFTERNOON AS DRIER AIR ADVECTS IN FROM THE
NORTH...WITH PRECIP SOUTH OF THE REGION BY SATURDAY EVENING AS THE
FRONT MOVES INTO THE TENNESSEE VALLEY.
REMAINDER OF THE SHORT TERM WILL BE QUIET AS BROAD HIGH PRESSURE
TAKES OVER ACROSS THE MIDWEST AND OHIO VALLEY. A MUCH COOLER DRIER
AIRMASS WILL BRING A REFRESHING CHANGE FOR THE SECOND HALF OF THE
WEEKEND AND INTO EARLY NEXT WEEK.
TEMPS...MAVMOS APPEARED REASONABLE THROUGHOUT THE SHORT TERM AS
HIGHS FALL BACK INTO THE 70S BOTH SATURDAY AND SUNDAY. ONE LAST
HUMID NIGHT FOR TONIGHT WITH MUCH MORE COMFORTABLE TEMPS FOR
SATURDAY/SUNDAY NIGHTS INTO THE LOWER AND MIDDLE 50S...WITH MAYBE
EVEN A FEW RURAL LOCATIONS FALLING INTO THE UPPER 40S.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
ISSUED AT 213 PM EDT FRI SEP 5 2014
MOSTLY ZONAL FLOW EARLY IN THE LONG TERM WILL GIVE WAY TO A BROAD
TROUGH OVER MUCH OF THE U.S. WHICH WILL ALLOW TEMPERATURES TO REMAIN
COOLER THAN NORMAL THROUGHOUT THE LONG TERM PERIOD. HIGH PRESSURE
DEPARTING TO THE EAST MONDAY NIGHT WILL COINCIDE WITH A FRONTAL
SYSTEM FORMING OVER THE CENTRAL U.S. AND SLOWLY MOVING ACROSS THE
AREA BRINGING CHANCES FOR THUNDERSTORMS INTO THE FORECAST TUESDAY
THROUGH THURSDAY. MODEL DIFFERENCES IN TIMING OF THE EXIT OF THE
SYSTEM MEAN KEEPING CHANCES IN THROUGH THURSDAY NIGHT...BUT BY
FRIDAY MOST EVERYTHING HAS THE SYSTEM OUT OF THE AREA AND HIGH
PRESSURE BUILDING IN BEHIND IT.
&&
.AVIATION /DISCUSSION FOR 051800Z TAF ISSUANCE/...
ISSUED AT 1249 PM EDT FRI SEP 5 2014
CAPPING INVERSION IS STILL IN PLACE OVER THE SITES AND WITH HIGH
CONVECTIVE TEMPERATURES THIS SHOULD INHIBIT CONVECTION TOO FAR AHEAD
OF THE COLD FRONT. THUS WILL PUSH BACK TIMING OF CONVECTION BY A
COUPLE HOURS WITH VCTS AT KLAF AFTER 21Z AND EXPLICIT THUNDER AT
23Z. STILL ANTICIPATE A LINE OF THUNDERSTORMS MOVING SOUTHEAST
THROUGH THE SITES...ALTHOUGH THERE IS INCREASING UNCERTAINTY ABOUT
HOW FAR SOUTH THE LINE WILL REACH WITH THE UPPER FORCING STAYING
TO THE NORTH. GUIDANCE IS INDICATING LOW CEILINGS AFTER FRONTAL
PASSAGE AND SOME LIGHT SHOWERS OR DRIZZLE AND THINK THIS LOOKS
REASONABLE. THUS AFTER BEING VFR THROUGH AROUND 0Z OR MORE SHOULD
SEE DETERIORATING FLYING CONDITIONS DURING THE NIGHT WHICH MAY NOT
IMPROVE UNTIL SATURDAY AFTERNOON OR EVENING.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN/JH
SHORT TERM...RYAN
LONG TERM....CP
AVIATION...CP
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1251 PM EDT FRI SEP 5 2014
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 324 AM EDT FRI SEP 5 2014
VERY WARM HUMID CONDITIONS TODAY WILL COME TO AN ABRUPT END AS A
COLD FRONT TRACKS THROUGH THE REGION WITH SHOWERS AND THUNDERSTORMS
TONIGHT AND SATURDAY. HIGH PRESSURE WILL BUILD IN BEGINNING SATURDAY
NIGHT WITH DRY AND MUCH COOLER WEATHER INTO EARLY NEXT WEEK.
THUNDERSTORM CHANCES WILL RETURN TUESDAY AND CONTINUE THROUGH MUCH
OF NEXT WEEK AS A COLD FRONT MOVES THROUGH THE GREAT LAKES AND OHIO
VALLEY.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 955 AM EDT FRI SEP 5 2014
.UPDATE...CURRENT FORECAST IS ON TRACK AND ONLY MINOR CHANGES MADE
WITH THIS UPDATE...MAINLY TO RAISE POPS SLIGHTLY OVER FAR NORTHERN
SECTIONS AS SHOWERS AND THUNDERSTORMS WERE ALREADY OVER NORTHEAST
ILLINOIS WHICH MAY BRUSH FAR NORTHERN AREAS IN A FEW HOURS.
PORTION OF PREVIOUS NEAR TERM DISCUSSION FOLLOWS...
MOST CONVECTION HAS REMAINED WELL NORTH/NORTHWEST OF THE FORECAST
AREA ALONG A COLD FRONT. MOST INTENSE STORMS ACROSS THE NORTHERN
GREAT LAKES THIS MORNING IN VICINITY OF A STRONGER SURFACE WAVE AND
A SHARPENING UPPER TROUGH. THE UPPER RIDGE WILL BUCKLE IN RESPONSE
TO THE AMPLIFYING UPPER TROUGH OVER THE UPPER MISSISSIPPI VALLEY...
ENABLING THE FRONTAL BOUNDARY TO SAG INTO THE NORTHERN FORECAST AREA
BY THIS EVENING.
AHEAD OF THE FRONT...ABUNDANT SUNSHINE AND SOUTHWEST FLOW WILL
PROVIDE FOR ANOTHER VERY WARM HUMID DAY FOR CENTRAL INDIANA. MID
LEVEL HEIGHTS WILL BEGIN TO FALL BY THE AFTERNOON AS THE FRONT
APPROACHES FROM THE NORTH AND COMBINED WITH VERY WEAK UPPER FORCING
AND A STRONGLY UNSTABLE AIRMASS...WILL INTRODUCE LOW CHANCE POPS
GRADUALLY INCREASING FROM THE NORTHWEST INTO THE EVENING. BOTH THE
WRF AND HRRR THIS MORNING APPEAR OVERDONE WITH RESPECT TO CONVECTIVE
DEVELOPMENT IN THE AFTERNOON...BUT ISOLATED STORMS CERTAINLY CANNOT
BE RULED OUT WITH THE PARAMETERS ABOVE. A LINE OF MORE ROBUST
CONVECTION IS EXPECTED TO DEVELOP THIS AFTERNOON IN THE VICINITY OF
THE FRONT OVER THE LOWER GREAT LAKES. THESE STORMS WILL BE
APPROACHING THE FORECAST AREA FROM THE NORTHWEST BY 00Z.
TEMPS...WITH 850MB TEMPS AT 20-21C AND A SOUTHWEST FLOW THIS
AFTERNOON...HAVE TRENDED TOWARDS THE WARMER MAVMOS FOR HIGHS IN THE
UPPER 80S AND LOWER 90S. MAX HEAT INDICES OF 95 TO 100 DEGREES THIS
AFTERNOON ARE EXPECTED AS WELL AND WILL HIGHLIGHT IN THE HWO.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 324 AM EDT FRI SEP 5 2014
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES THROUGH LATE SATURDAY AS
THE FRONT MOVES THROUGH THE REGION. 00Z MODEL GUIDANCE HAS GENERALLY
SLOWED THE PASSAGE OF THE BOUNDARY WITH PRECIP CHANCES LINGERING
OVER MUCH OF THE SOUTHERN HALF OF THE FORECAST AREA FOR A GOOD
PORTION OF SATURDAY.
FIRST ISSUE IS WITH EXPECTED CONVECTION MOVING INTO THE FORECAST
AREA FROM THE NORTHWEST THIS EVENING. WHILE STRONGER MID/UPPER LEVEL
FORCING AND STRONGER BL SHEAR WILL REMAIN WELL NORTH OF THE
REGION...PRESENCE OF CONVECTION MOVING INTO A STRONGLY UNSTABLE
AIRMASS WITH HIGH PRECIP WATER VALUES SHOULD BE ABLE TO COMPENSATE
FOR STORM INTENSITY MAINTENANCE INTO THE FORECAST AREA THIS EVENING.
POTENTIAL FOR A FEW OF THESE STORMS TO BE SEVERE...ESPECIALLY IF
CONVECTION CAN LAY DOWN A COLD POOL AND PROVIDE FOR AN ENHANCED
DAMAGING WIND THREAT FOR A SHORT PERIOD OF TIME. AS INSTABILITY
WANES AND THE STORMS MOVE AWAY FROM THE LIMITED BL SHEAR...SHOULD
SEE STORMS WEAKEN AND DIMINISH IN COVERAGE BY LATE EVENING SOUTH OF
I-70. WILL CARRY LIKELY POPS NORTH OF I-70 WITH LOWER POPS FURTHER
SOUTH.
THE FRONT WILL CONTINUE ITS SLOW PROGRESS SOUTH THROUGH THE FORECAST
AREA SATURDAY. MID LEVEL DEFORMATION AXIS PASSING THROUGH THE LOWER
GREAT LAKES WITH THE UPPER TROUGH WILL LINGER PRECIP CHANCES OVER
THE REGION...BUT WITH AN ABUNDANCE OF CLOUDS AND LIMITED
INSTABILITY...HARD TO JUSTIFY MUCH MORE THAN AN ISOLATED THUNDER
THREAT WITH SHOWERS. SHOWERS WILL GRADUALLY SHIFT INTO SOUTHERN
COUNTIES DURING THE AFTERNOON AS DRIER AIR ADVECTS IN FROM THE
NORTH...WITH PRECIP SOUTH OF THE REGION BY SATURDAY EVENING AS THE
FRONT MOVES INTO THE TENNESSEE VALLEY.
REMAINDER OF THE SHORT TERM WILL BE QUIET AS BROAD HIGH PRESSURE
TAKES OVER ACROSS THE MIDWEST AND OHIO VALLEY. A MUCH COOLER DRIER
AIRMASS WILL BRING A REFRESHING CHANGE FOR THE SECOND HALF OF THE
WEEKEND AND INTO EARLY NEXT WEEK.
TEMPS...MAVMOS APPEARED REASONABLE THROUGHOUT THE SHORT TERM AS
HIGHS FALL BACK INTO THE 70S BOTH SATURDAY AND SUNDAY. ONE LAST
HUMID NIGHT FOR TONIGHT WITH MUCH MORE COMFORTABLE TEMPS FOR
SATURDAY/SUNDAY NIGHTS INTO THE LOWER AND MIDDLE 50S...WITH MAYBE
EVEN A FEW RURAL LOCATIONS FALLING INTO THE UPPER 40S.
&&
.LONG TERM /MONDAY THROUGH THURSDAY NIGHT/...
ISSUED AT 342 AM EDT FRI SEP 5 2014
DRY CONDITIONS CAN BE EXPECTED ON MONDAY WITH ZONAL FLOW ALOFT AND
WEAK HIGH PRESSURE STILL AT THE SURFACE. HOWEVER...THE PATTERN WILL
QUICKLY SHIFT BY TUESDAY AS A BROAD UPPER TROUGH ENTERS THE AREA.
WIDESPREAD SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS CENTRAL
INDIANA AS EARLY AS TUESDAY MORNING...WITH INCREASING CHANCES
THROUGH THE COURSE OF THE EXTENDED PERIOD AS A COLD FRONT TRACKS
ACROSS THE AREA ON WEDNESDAY NIGHT/THURSDAY. PRECIP CHANCES WILL
TAPER OFF TOWARD THE END OF THE PERIOD...BUT WILL KEEP MENTION OF
SHOWERS AND THUNDERSTORMS IN THE FORECAST THROUGH THURSDAY NIGHT TO
ACCOUNT FOR PASSAGE OF UPPER LOW. TEMPS WILL CONTINUE TO DROP WELL
BELOW NORMAL THROUGH THE COURSE OF THE EXTENDED PERIOD WITH HIGH
TEMPS ONLY IN THE UPPER 60S/LOW 70S BY FRIDAY.
&&
.AVIATION /DISCUSSION FOR 051800Z TAF ISSUANCE/...
ISSUED AT 1249 PM EDT FRI SEP 5 2014
CAPPING INVERSION IS STILL IN PLACE OVER THE SITES AND WITH HIGH
CONVECTIVE TEMPERATURES THIS SHOULD INHIBIT CONVECTION TOO FAR AHEAD
OF THE COLD FRONT. THUS WILL PUSH BACK TIMING OF CONVECTION BY A
COUPLE HOURS WITH VCTS AT KLAF AFTER 21Z AND EXPLICIT THUNDER AT
23Z. STILL ANTICIPATE A LINE OF THUNDERSTORMS MOVING SOUTHEAST
THROUGH THE SITES...ALTHOUGH THERE IS INCREASING UNCERTAINTY ABOUT
HOW FAR SOUTH THE LINE WILL REACH WITH THE UPPER FORCING STAYING
TO THE NORTH. GUIDANCE IS INDICATING LOW CEILINGS AFTER FRONTAL
PASSAGE AND SOME LIGHT SHOWERS OR DRIZZLE AND THINK THIS LOOKS
REASONABLE. THUS AFTER BEING VFR THROUGH AROUND 0Z OR MORE SHOULD
SEE DETERIORATING FLYING CONDITIONS DURING THE NIGHT WHICH MAY NOT
IMPROVE UNTIL SATURDAY AFTERNOON OR EVENING.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN/JH
SHORT TERM...RYAN
LONG TERM....TDUD
AVIATION...CP
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1224 PM CDT FRI SEP 5 2014
.SYNOPSIS...
ISSUED AT 304 AM CDT FRI SEP 5 2014
COLD FRONT OVER SOUTHEAST IOWA WILL MOVE SOUTHEAST OF IA TODAY AS
A WAVE LIFTS NORTHEAST ALONG THE FRONT THIS AFTERNOON AND EVENING.
HIGH PRESSURE WILL BUILD INTO THE STATE TODAY AND TONIGHT. THE
NEXT FRONTAL SYSTEM WILL APPROACH THE STATE MONDAY...MOVING SLOWLY
THROUGH IOWA THROUGH MID WEEK.
&&
.SHORT TERM /TODAY/...
ISSUED AT 304 AM CDT FRI SEP 5 2014
SLOW MOVING COLD FRONT WILL FINALLY CLEAR THE FAR SOUTHEAST
CORNER OF THE FORECAST AREA B/T 12-14Z THIS MORNING. THE
ASSOCIATED BROKEN LINE OF WEAK CONVECTION LOOKS TO LINGER
THROUGH SUNRISE BEFORE THE LLJ WEAKENS AND RESULTS IN STORMS
DIMINISHING IN INTENSITY AND COVERAGE BY 12Z OR EVEN SOONER. HAVE
LIKELY POPS GOING THROUGH THIS TIME...GENERALLY B/T THE HWY 20 AND
HWY 30 CORRIDORS...THEN CHANCE POPS ACROSS THE SOUTHERN HALF OF
THE FORECAST AREA THE REMAINDER OF THE MORNING.
NEXT SHORTWAVE LOOKS TO ENTER THE SOUTHERN PORTION OF THE STATE
LATER THIS MORNING INTO THE AFTERNOON HOURS AND BRINGS ANOTHER
ROUND OF SHOWERS/TSTMS ACROSS THE FORECAST AREA INTO THIS
EVENING. BROAD LARGE SCALE FORCING WITH THIS SHORTWAVE AND ENOUGH
THETA-E ADVECTION TO WARRANT CHANCE POPS ACROSS THE SOUTHERN TWO-
THIRDS OF THE FORECAST LATE THIS MORNING AND INTO THE AFTERNOON.
THE 05.05Z HRRR SEEMS A BIT TOO FAST WITH RAIN BUT AGREE WITH THE
COVERAGE ACROSS CENTRAL IOWA. THE 05.00Z HOPWRF SIMILAR WITH THE
COVERAGE BUT THINK IT HAS A BETTER HANDLE ON THE TIMING OF THE
PRECIP AND LEANED TOWARD THE HOPWRF FOR POP TRENDS TODAY.
CONSIDERED A NON-DIURNAL TEMPERATURE TREND TODAY BUT SHOULD WARM UP
ENOUGH LATER THIS MORNING INTO THE AFTERNOON ACROSS MUCH OF THE
FORECAST AREA...SO HAD LOW CONFIDENCE IT WOULD BE WIDESPREAD ENOUGH
TO MENTION.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 304 AM CDT FRI SEP 5 2014
CLEARING WILL SPREAD SOUTHEAST A HIGH PRESSURE BUILDS IN TO THE
STATE. THE WEEKEND LOOKS TO BE A QUITE WEEKEND WITH NO RAINFALL
EXPECTED AND TEMPERATURES BELOW NORMAL.
THE WEATHER PATTERN WILL BECOME MORE ACTIVE NEXT WEEK. DECENT
THETA-E ADVECTION BEGINS BY MONDAY MORNING AND WILL CONTINUE
PERIODICALLY THROUGH MID WEEK. RAINFALL AMOUNTS WILL HINGE ON HOW
MUCH OF THE MOISTURE FROM "NORBERT" IS PULLED INTO THE SYSTEM. IT
APPEARS THAT THE BULK OF THE MOISTURE WILL BE SWEPT EAST PASSING
OVER SOUTHERN IA OR FARTHER SOUTH. A STRONG UPPER TROUGH WILL
CARVE OUT FOR THE FOLLOWING WEEKEND. MODEL CONTINUITY IS DECENT
WITH THE MACRO SYSTEMS...DIFFERING IN DETAIL...BUT THE MESSAGE OF
SHARPLY COLDER IS PLAYED BY ALL.
&&
.AVIATION...05/18Z
ISSUED AT 1224 PM CDT FRI SEP 5 2014
THICK LAYERED CLOUDS WILL REMAIN ACROSS THE AREA THIS AFTERNOON
INTO EVENING...THEN CLEAR FROM NORTHWEST TO SOUTHEAST. THIS WILL
RESULT IN MVFR CIGS AT TIMES THIS AFTERNOON...ALONG WITH PERIODS
OF SHRA/TSRA MAINLY AT DSM/OTM WHICH HAVE BEEN COVERED WITH TEMPO
GROUPS. AFTER THIS EVENING AS CLEARING OCCURS CONDITIONS WILL
IMPROVE RAPIDLY...WITH LIGHT WINDS AND SKC EXPECTED FROM LATER
TONIGHT THROUGH TOMORROW.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...MS SEP 14
SHORT TERM...PODRAZIK
LONG TERM...MS SEP 14
AVIATION...LEE
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1259 PM CDT FRI SEP 5 2014
...UPDATED FOR AVIATION...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 100 AM CDT FRI SEP 5 2014
EVEN THOUGH WE HAVE NOT REACHED THE EQUINOX (23 SEPT 2014), WE ARE CERTAINLY
IN METEOROLOGICAL FALL AND TODAY WILL GIVE US THE FIRST DOSAGE OF FALL-
LIKE WEATHER WITH COOL TEMPERATURES, SHOWERS, CLOUDS, AND A RAW NNE/NE
WIND.
FOR THE REST OF THIS MORNING, HEAVILY BIASED THE SPATIOTEMPORAL ARRANGEMENT
OF POPS AND RESULTANT WEATHER GRIDS TO THE 4 KM NAM. THIS MODEL HAD
MORE OF A CLUE WITH INITIAL CONDITIONS THAN COMPARED TO THE OPERATIONAL
NAM AND THE WRF. RECENT HRRR GUIDANCE IS ALSO SOMEWHAT IN AGREEMENT
WITH THE 4 KM NAM AS WELL, ALBEIT, A BIT LIBERAL WITH THE EASTWARD
PROGRESSION. FOR THE BOTTOM LINE, SHOWERS AND ISOLATED THUNDERSTORMS
WILL CONTINUE TO DEVELOP ALONG THE 800-700-HPA BAROCLINIC BOUNDARY WITH
UPSLOPE/300K ISENTROPIC LIFT. BUFKIT PLUME SPREADS STILL SUPPORT A GOOD/SOAKING
RAIN WITH PRECIPITATION AMOUNTS GENERALLY IN THE 0.50-1.00" RANGE ALONG
THE SW TO NE ORIENTED BAROCLINIC BOUNDARY. THE AREA THAT WILL SEE THE
LEAST IS ACROSS SOUTH-CENTRAL KANSAS. EVENTUALLY, SUBSIDENCE AND ISENTROPIC
DOWNGLIDE WILL DEVELOP IN THE WAKE OF A PASSING SYNOPTIC WAVE. THE END
RESULT WILL BE A REDUCTION IN COVERAGE AND INTENSITY OF THE SHOWERS
LATER ON TODAY. LASTLY, SEVERE WEATHER IS NOT EXPECTED TODAY. JUST AN
OCCASIONAL LIGHTNING BOLT, BUT NOTHING ORGANIZED/SEVERE.
THE OTHER STORY FOR TODAY IS MAXIMUM TEMPERATURES. SIDED WITH THE COOLER
SOLUTION WITH MORE LOW 60SF ACROSS RAIN-COOLED AREAS AND KEPT THE WARMEST
ACROSS SOUTH-CENTRAL KANSAS, WHERE THIS AREA WILL BE IN THE WARM SECTOR
LONGER (WENT WITH AROUND 80F FOR MEDICINE LODGE).
IF SHOWERS AND ISOLATED THUNDERSTORMS DO CONTINUE THROUGH THE OVERNIGHT
HOURS, IT WOULD BE MAINLY NEAR THE OKLAHOMA BORDER AS THE BAROCLINIC
BOUNDARY SINKS SOUTH. FOR MINIMUMS, TEMPERATURES WILL FEEL THE COLDEST
IN QUITE A WHILE (LIKE SINCE LAST MAY). AS CLOUDS ERODE AND UNDER THE
INFLUENCE OF HIGH PRESSURE AND SINGLE DIGIT 850-HPA TEMPERATURES, THINK
THAT SOME AREAS (LIKE THE INTERSTATE 70 CORRIDOR) COULD SEE SOME UPPER
40SF. THE REST OF THE AREA WILL BE IN THE LOW TO MID 50SF. GOOD NIGHT
TO FINALLY OPEN UP THAT WINDOW AND BRING SOME CRISP BUT REFRESHING
FALL AIR IN AND GIVE THE AIR CONDITIONING UNIT A REST.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 348 AM CDT FRI SEP 5 2014
A TRANSITION TO A MORE FALL PATTERN, AT LEAST TEMPORARILY, IS IN
PROGRESS ON THIS SIDE OF THE HEMISPHERE WITH VIGOROUS UPPER LEVEL
TROUGHS RIPPLING THROUGH THE FLOW AND OCCASIONAL INCURSIONS OF
CANADIAN AIR INTO THE CENTRAL AND EASTERN UNITED STATES. CHALLENGES
FOR THE EXTENDED PERIOD INCLUDE THE EFFECTS OF INJECTION OF TROPICAL
MOISTURE FROM HURRICANE NORBERT ON PRECIPITATION COVERAGE EARLY NEXT
WEEK AND ANTICIPATING THE AMPLITUDE OF THE AMPLIFYING TROUGH THAT
DIGS INTO THE NORTHERN PLAINS AND SOUTHERN CANADA BY THE MIDDLE OF
NEXT WEEK.
LARGE SCALE FORCING FROM THE TROPICS REMAINS POORLY ORGANIZED.
OUTGOING LONG WAVE RADIATION SUGGESTS THAT THERE IS A WEAK COHERENT
SIGNAL THAT PROJECTS ONTO A MADDEN JULIAN OSCILLATION NEAR 140E THAT
MAY APPROACH THE DATELINE AROUND 15-16 SEPTEMBER, BUT MOST OF THE
GLOBAL MODELS SUGGEST THAT TROPICAL THUNDERSTORMS WILL REDEVELOP
BACK IN THE WESTERN INDIAN OCEAN BY MID SEPTEMBER. TEMPERATURES HAVE
BEEN ANOMALOUSLY COOL IN CENTRAL ASIA RECENTLY, AND EASTERLY FLOW
AGAINST THE MOUNTAINS IN EASTERN ASIA APPEAR TO BE CONTRIBUTING TO
THE POSITIVE MOUNTAIN TORQUE ON THE ATMOSPHERE. RELATIVE
ATMOSPHERIC ANGULAR MOMENTUM HAS BEEN TRENDING UPWARD SLOWLY, AND
THE FLOW FOR THE NEXT WEEK OR SO IS BEST REPRESENTED BY PHASE 4 OF
THE GLOBAL WIND OSCILLATION. THIS CORRELATES WITH ANTICYCLONIC
FLOW IN THE WESTERN UNITED STATES. AS SUCH, THE IDEA OF
MAINTAINING RIDGING FROM THE SOUTHWESTERN UNITED STATES TO WESTERN
CANADA NEXT WEEK IS VERY REASONABLE. THE ECMWF CONTINUES TO BE
MORE AMPLIFIED WITH A TROUGH THAT DIGS INTO THE NORTHERN PLAINS
NEXT FRIDAY THAN IS THE GFS. SOME OF THE GFS ENSEMBLE MEMBERS ARE
EVEN DEEPER AND SLOWER WITH THE CLOSED CYCLONE THAT DEEPENS NEAR
THE CANADIAN BORDER NEXT THURSDAY THAN THE ECMWF, AND THE GEM
ENSEMBLE MEMBERS EXHIBIT CONSIDERABLE SPREAD. THE ECMWF MAY BE
SLIGHTLY OVERDONE WITH THE STRENGTH OF THE TROUGH DIGGING INTO THE
NORTHERN PLAINS LATE NEXT WEEK, BUT THE GENERAL PATTERN LOOKS
GOOD. THERE WILL BE A SIGNIFICANT INVASION OF CANADIAN AIR INTO
THE CENTRAL AND NORTHERN PART OF THE COUNTRY NEXT WEDNESDAY, AND
THERE PROBABLY WILL BE WIDESPREAD FROST AND SOME FREEZING
TEMPERATURES ACROSS THE NORTHERN PLAINS NEXT FRIDAY AND SATURDAY
MORNINGS.
AFTER THE COLD AIR DRAINS SOUTHWARD NEXT WEEK, IT APPEARS LIKELY
THAT A MORE ZONAL FLOW REGIME WITH BROAD RIDGING IN THE WESTERN PART
OF THE COUNTRY WILL BECOME ESTABLISHED. TEMPERATURES WILL RETURN TO
NEAR OR ABOVE SEASONAL AVERAGES BY 16-17 SEPTEMBER, AND MOST OF THE
REST OF THE MONTH SHOULD BE FAIRLY WARM.
IN THE MORE IMMEDIATE FUTURE, SATURDAY SHOULD BE COOL WITH LIGHT
WINDS AND CLEARING SKIES AS HIGH PRESSURE BUILDS INTO THE CENTRAL
PLAINS. HIGHS IN THE LOWER HALF OF THE 70S CAN BE EXPECTED WITH H8
TEMPERATURES FROM 12 TO 15 DEGREES C. LOW LEVEL FLOW WILL RETURN TO
THE SOUTH SATURDAY NIGHT BUT WILL REMAIN LIGHT AND VARIABLE FOR MUCH
OF THE NIGHT IN CENTRAL KANSAS. TEMPERATURES WILL FALL TO NEAR 50
AGAIN IN NORTH CENTRAL KANSAS. LOWS WILL BE SOMEWHAT WARMER NEAR THE
COLORADO BORDER WHERE WARM AIR ADVECTION WILL BEGIN EARLIER IN THE
NIGHT.
PRESSURES WILL FALL IN THE NORTHERN ROCKIES AND PLAINS SATURDAY
NIGHT AND SUNDAY AS THE NEXT VIGOROUS UPPER LEVEL TROUGH APPROACHES
BRITISH COLUMBIA, AND A PLUME OF WARM AIR WILL SPREAD EAST FROM THE
ROCKIES. MID LEVEL FRONTOGENESIS LIKELY WILL SUPPORT SOME MID LEVEL
CLOUDINESS SUNDAY, AND ISENTROPIC LIFTING OVER THE RETREATING COOL
AIR MASS AS A LOW LEVEL JET DEVELOPS SUNDAY NIGHT LIKELY WILL
SUPPORT EVOLUTION OF SCATTERED NOCTURNAL ELEVATED SHOWERS AND
THUNDERSTORMS. IT IS UNCERTAIN EXACTLY HOW FAR WEST THE SHOWERS WILL
DEVELOP, BUT THE THE MOST LIKELY AREA IS EAST OF HIGHWAY 283.
MONDAY WILL BE WARM AGAIN, AND HIGH LEVEL TROPICAL MOISTURE FROM
HURRICANE NORBERT WILL BEGIN TO SPREAD INTO THE HIGH PLAINS.
THUNDERSTORMS LIKELY WILL INITIATE ALONG A CONVERGENCE ZONE FROM
NORTHWEST KANSAS INTO EASTERN COLORADO AND SPREAD EAST DURING THE
EVENING. THE GFS CARRIES THE REMNANTS OF NORBERT INTO THE CENTRAL
PART OF THE COUNTRY TUESDAY, WHILE THE ECMWF IS A LITTLE SLOWER TO
EJECT THE CARCASS. BOTH MODELS CARRY A SUBSTANTIAL INJECTION OF HIGH
LEVEL TROPICAL MOISTURE ACROSS THE CENTRAL PART OF THE COUNTRY, AND
A WEAK FRONTAL BOUNDARY IS LIKELY TO EXIST IN WESTERN KANSAS. THE
SYNOPTIC DETAILS ARE UNCERTAIN, BUT ANY CONVERGENCE ZONE WILL BE
SUFFICIENT TO SUPPORT THUNDERSTORM DEVELOPMENT.
CANADIAN AIR WILL INVADE KANSAS WEDNESDAY, AND MUCH COOLER WEATHER
WILL PREVAIL THURSDAY AND FRIDAY. A REINFORCING SURGE OF COLD AIR
WILL ARRIVE ABOUT FRIDAY. UPSLOPE FLOW AND EXTENSIVE CLOUDINESS MAY
KEEP TEMPERATURES IN THE 50S FRIDAY. RAIN CHANCES WILL DEPEND ON THE
STRENGTH OF THE UPPER LEVEL TROUGH THAT DIGS INTO THE NORTHERN PART
OF THE COUNTRY. IF THE ECMWF IS CORRECT, TEMPERATURES COULD DROP
INTO THE UPPER 30S AS FAR SOUTH AS NORTHERN KANSAS WHEN THE CLOUD
COVER FINALLY CLEARS OUT. SUCH DETAILS ARE HIGHLY UNCERTAIN THAT
FAR IN THE FUTURE, HOWEVER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1253 PM CDT FRI SEP 5 2014
AREAS OF MVFR/IFR CIGS WILL CONTINUE INTO TONIGHT WITH CIGS
IMPROVING TO VFR AFTER 12-15Z. AREAS OF LIGHT RAIN SHOWERS WILL
GRADUALLY DECREASE BY 00Z AS THE CURRENT TROPICAL WAVE MOVES EAST.
LIGHT NORTH TO NORTHEAST WINDS OF 10-15KT WILL CONTINUE.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 63 50 73 53 / 90 30 10 10
GCK 61 49 73 53 / 100 30 10 10
EHA 62 51 73 54 / 90 40 10 10
LBL 66 53 74 54 / 90 40 20 10
HYS 61 49 73 50 / 80 30 10 10
P28 80 58 74 56 / 50 50 20 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SUGDEN
LONG TERM...RUTHI
AVIATION...KRUSE
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
141 PM EDT FRI SEP 5 2014
.SYNOPSIS...
HIGH PRESSURE ALONG THE EAST COAST WILL PROVIDE A VERY WARM AND HUMID
SUMMER LIKE AFTERNOON FOR THE REGION. THERE IS A CHANCE FOR
AFTERNOON SHOWERS AND THUNDERSTORMS ESPECIALLY IN NORTHEAST
PENNSYLVANIA AND ALSO IN NORTH CENTRAL NEW YORK. AN APPROACHING
COLD FRONT WILL BRING THE LIKELIHOOD OF MORE SHOWERS AND
THUNDERSTORMS, STARTING LATE TONIGHT, THEN LASTING THROUGH MUCH OF
SATURDAY. ONCE THIS FRONT PUSHES OFF THE COAST, A NEW HIGH
PRESSURE SYSTEM WILL ADVANCE TOWARD THE REGION SUNDAY, WITH DRIER
AND COOLER WEATHER.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL WAVE MOVING ACRS THE
OHIO VALLEY WHICH WAS SUPPORTG SOME CONVECTIVE ACVTY OVER THE
UPPER LAKES. THE SOUTHERN EDGE OF THIS WAS AFFECTING SRN ONT AND
LAKE ONTARIO AT THIS TIME. THIS ACVTY WAS MOVING EASTWARD AS THE
UPPER LEVEL WAVE PROPAGATES TO THE E-NE THIS AFTERNOON. THE
GFS...NAM...EURO...CMC AND RAP ALL SHOW THIS UPPER LEVEL FEATURE
WORKING ACRS NY AND PA BTWN 18Z AND 00Z WITH ONLY SOME SLIGHT
COOLING ALOFT ON THE ORDER OF BARELY 1C AT 500 MB. THIS WILL OCCUR
IN CONCERT WITH THE MAX HEATING OF THE AFTERNOON AND FAIRLY RICH
BOUNDARY LAYER MOISTURE ESPECIALLY ALONG THE LAKE ONTARIO PLAIN
AND IN NE PA. HENCE WHERE THERE IS ENUF INSTABILITY THERE WILL BE
A FEW SHRA OR TSRA POPPING UP.
MODEL INSTABILITY FIELDS FROM THE RAP...GFS...NAM ALSO SHOW A
RIBBON OF INSTABILITY OVER 1000 J/KG ALONG THE LAKE ONTARIO PLAIN
AS WELL AS ACRS NE PA WHERE CAPES CUD EXCEED 2000 J/KG (AS PER 06Z
NAM AT LEAST) WITH A MINIMUM IN CAPE ACROSS FAR NRN PA AND SC NY.
BELIEVE SOME ISLD TO SCT TSRA WILL FIRE THIS AFTERNOON WHEN THIS
WAVE INTERACTS WITHIN THESE INSTABILITY AXISES WITH COVERAGE IN
THE ISLD TO SCT RANGE IN NC NY AND NE PA SO HAVE ADDED POPS FOR
LATER TODAY IN NE PA TO ACCOUNT FOR. JUST TWEAKED POPS IN NC NY
FROM EARLIER SHIFT. 06Z NAM SOUNDING ACTUALLY HAS 3000 J/KG OF
CAPE AT AVP ARND 22-00Z! THE FORCING IS WEAK BUT IF SOMETHING
FIRES THERE CUD BE SOME VERY HEAVY RAIN LOCALLY WITH PWATS AROUND
1.75 INCHES AND THE POTENTIAL FOR STORMS TO ANCHOR ON THE
MOUNTAINS IN SUCH A WEAK FLOW REGIME. THE WINDS ARE STRONGER IN
THE LOW-LEVELS BETWEEN 0 AND 3 KM THEN WEAKEN ARND 3 TO 6 KM AND
THEN STRENGTHEN AGAIN. WE WILL HAVE TO WATCH THIS CAREFULLY THIS
AFTERNOON. ANYTHING THAT FIRES DOWN IN NE PA CUD CAUSE HEAVY RAIN.
AND.... IF CAPE VALUES ACTUALLY REACH 3000 J/KG AS PER 06Z NAM YOU
CANT RULE OUT A MICROBURST...EVEN IF CAPES EXCEED 2000 J/KG. WILL
MENTION IN HWO FOR NE PA THIS AFTERNOON. FARTHER N IN NC NY...ACVTY
LIKELY WILL BE MORE ISOLATED WITH LESS INSTABILITY. BUT THERE WAS STRGR
WIND FIELDS. THIS LIKELY WILL LESSENING THREAT FOR ANY SLOW MOVING HEAVY
RAIN PRODUCING STORMS. CAPES CUD REACH 500 TO 1000 J/KG WITH SOME
LOW-LEVEL SHEAR ARND 15-20 KNOTS BUT WEAKER DEEP LAYER SHEAR. NOT
EXPECTING ANY ORGANIZED SVR ACVTY IN NC NY AS A RESULT UNLESS
CAPES GET HIGHER THAN PROJECTED.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
430 AM UPDATE... OVERALL...MODEL GUIDANCE REMAINS SIMILAR TO THE
LAST SVRL RUNS...IN SHOWING AN ADVANCING SFC COLD FRNT THROUGH THE
AREA ON SAT...FOLLOWED BY HIGH PRES AND S/WV RIDGING ALOFT SUN.
SHWRS/TSTMS ALG AND AHD OF THE COLD FRNT SHOULD INCREASE IN
COVERAGE LTR TNT OVER OUR NRN AND WRN ZNS...WITH A BAND OF FAIRLY
WIDESPREAD CONVECTION PUSHING SEWD THROUGH CNY/NE PA DURG THE DAY
SAT. WE`LL CONTINUE TO EMPLOY LIKELY POPS FOR MUCH OF THIS TIME
FRAME.
THE POTENTIAL FOR STG/SVR STORMS ON SAT LOOKS MUDDLED OVER THE
FA...WITH SIG CLOUD COVER LIKELY TO LIMIT DESTABILIZATION FOR AT
LEAST THE NWRN HALF OF THE CWA (CNTRL SRN TIER...FINGER LKS...WRN
MOHAWK VLY...AND SRN TUG HILL RGNS OF NY). HOWEVER...FARTHER S AND
E...THERE ARE NOW SOME INDICATIONS THAT THE SFC BNDRY MAY SLOW
JUST ENUF (ROUGHLY AN 18-21Z FROPA) TO ALLOW SOME MODEST HEATING
(TEMPS INTO THE LWR 80S)...WITH PROGGED ML CAPES IN THE
NEIGHBORHOOD OF 1000 J/KG. GIVEN DEEP-LYRD SHEAR OF 25-30 KT BY
THIS TIME...THE ENVIR COULD BECOME MARGINALLY SUPPORTIVE OF STG
GUSTY WINDS. THUS...WE`VE HIGHLIGHTED THIS POTENTIAL IN THE HWO
SAT FOR OUR FAR ERN AND SRN ZNS (OTSEGO CNTY...THE WRN
CATSKILLS...THE POCONOS...AND THE WILKES-BARRE SCRANTON AREA).
SPURRED ON BY A FAIRLY AMPLIFIED S/WV...THE COLD FRNT SHOULD
PROGRESS OFF THE COAST SAT NIGHT...WITH ANY LINGERING CONVECTION
ENDING EARLY IN THE EVE.
SUN SHOULD BE COOLER (HIGHS MAINLY IN THE 70-75 RANGE)...UNDER PTLY TO
MOSTLY SUNNY SKIES...WITH A SFC RIDGE BLDG IN FROM THE W.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
130 PM UPDATE...
EXPECT SFC HIPRES TO BE BUILDING INTO THE CANADIAN MARITIMES AT
THE START OF THE LONG TERM PD. A WEAK SFC LOW WL LKLY DVLP ALONG
THE ERN SEABOARD TUE MRNG AS WV RIDES UP ALONG THE COAST BUT WITH
1030MB HIGH CONTROLLING AREA WX NOT EXPECTING MUCH IN THE WAY OF
PCPN TO MV INTO CWA UNTIL MORE TWD TUE EVNG AND EVEN AT THAT
EXPECT IT TO BE A LONG SHOT.
CHC FOR SHOWERS/TSTMS CAN BE EXPECTED BEGINNING WED MRNG WITH
ANOTHER TROF (DEEPER ON EC VS GFS) WORKING ITS WAY INTO THE
NORTHEAST U.S. MODELS DIFFER ON POP CHANCES AFTR WED NGT WITH 12Z GFS
MUCH QUICKER MVG LOPRES THRU THAN 00Z EC. MAIN REASON IS THAT 00Z
EC IS MUCH MORE AMPLIFIED WITH SYSTEM AND DEEPER WITH SFC LOW.
THIS IS MORE IN LINE WITH GFS ENSEMBLE MEAN AND MAJORITY OF THE
ENSEMBLE MEMBERS. EXPECT TEMPS THRU THE PD TO BE NEAR.
&&
.AVIATION /17Z FRIDAY THROUGH TUESDAY/...
18Z UPDATE...
FEW-SCT CIRRUS CLOUDS DRIFTING THRU THIS AFTN WITH AN OCNL VFR
CUMULUS DEVELOPING BUT NOT ENOUGH FOR AVIATION CONCERNS. EXPECT
VFR TO CONTINUE THROUGH THE PRE-DAWN HOURS. COLD FRONT WILL
APPROACH FROM THE NORTH AND WEST AND LOW CLOUDS MAY DEVELOP AHEAD
OF THIS FEATURE, HOWEVER CONFIDENCE ON THIS OCCURRING IS NOT
HIGH. THUS HAVE TEMPO`D IN LOW MVFR RESTRICTION TO ELM BETWEEN 09Z
AND 12Z AS CHANCES FOR FOG WILL EXIST IF CLOUDS DO NOT DEVELOP.
-SHRA LOOKS TO HOLD OFF UNTIL AFTER 13Z ACROSS NRN NY TERMINALS
(SYR AND RME). -SHRA EXPECTED AT REMAINING NY TERMINALS BETWEEN
14Z AND 18Z WITH AVP REMAINING OUT OF -SHRA UNTIL AFTER 18Z.
THUNDER LOOKS POSSIBLE AT SOUTHERN TERMINALS (ITH, ELM, BGM AND
AVP) BUT HAVE HELD OFF ON MENTION IN TAFS AT THIS TIME.
WINDS OUT OF THE SSW AROUND 10KTS WILL BECOME LIGHT OVERNIGHT
INCREASE TO 5-10KTS FROM THE SOUTH OUT OF THE SSW AHEAD OF THE
FRONT BY MORNING.
OUTLOOK...
SAT NIGHT...MVFR RESTRICTIONS POSSIBLE BEHIND FRONT.
SUN-TUE...MOSTLY VFR WITH POTENTIAL FOR IFR RESTRICTIONS EACH
MORNING, ESPECIALLY ELM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN/MLJ
NEAR TERM...DJN
SHORT TERM...MLJ
LONG TERM...PVN
AVIATION...PVN
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
330 PM CDT FRI SEP 5 2014
.DISCUSSION...
BASED ON THE EXPECTED OVERNIGHT LOW TEMPS...CURRENT TOVER VALUES ARE
NEAR 0 AT BNA...AND -3 AT BOTH CKV AND CSV. NUMERIC DATA DOES SHOW
SOME REDUCTION OF VSBYS DUE TO FOG POTENTIAL AS WELL. EXPECTED
DEWPOINT DEPRESSIONS WILL BE 2 DEGREES OR LESS BY 12Z. THUS...WILL
OPT TO INCLUDE SOME LATE NIGHT PATCHY FOG ACROSS THE AREA.
OTW...ISOL LIGHT CONVECTION CONTINUES THIS AFTERNOON ACROSS EASTERN
AREAS. ANOTHER AREA OF CONVECTION IS NOT REALLY ATTEMPTING TO
ADVANCE OUR WAY FROM WESTERN KY. THIS IS IN ADVANCE OF AN
APPROACHING COLD FRONT WHICH SHOULD REACH OUR AREA TOMORROW
MORNING AFTER SUNRISE. HRRR PICKS UP ON THE AFOREMENTIONED
CONVECTION TO OUR NORTHWEST BUT DOES LITTLE IN THE WAY TO BRING
THAT ACTIVITY ACROSS OUR AREA. TURNS OUT...THE UPPER LEVEL
DYNAMICS OVERNIGHT TONIGHT LOOK WEAK. SO EVEN THOUGH THE FRONT
WILL REACH OUR NORTHWESTERN COUNTIES AROUND SUNRISE...THERE MAY
NOT BE MUCH ACTIVITY. SO...FOR TONIGHT`S FCST...WILL INCLUDE JUST
20 PERCENT POPS...PERHAPS A LITTLE HIGHER PLATEAU IF LATEST RADAR
TRENDS LEAN TOWARD CONVECTIVE EXPANSION.
ON SATURDAY...COLD FRONT WILL MOVE SOUTH OF THE AREA BUT THE
WESTERLIES ALOFT WILL BEGIN TO GAIN SOME STRENGTH. WITHIN THAT
WESTERLY FLOW...A SERIES OF DISTURBANCES WILL CROSS THE AREA AND
BRING A BETTER CHANCE...40% OR SO...OF SHOWERS. SHOWALTER VALUES ARE
NEGATIVE WITH DESCENT CAPE BY AFTERNOON. THEREFORE...WILL OPT TO
INCLUDE THUNDER STORM POTENTIAL AS WELL.
BY SATURDAY NIGHT...THE FRONT WILL BE WELL SOUTH OF THE AREA WITH
850 MB FLOW NORTHERLY AS WELL. UPPER LEVEL WESTERLIES NOW LEANING
TOWARD MORE OF AN NVA REGIME AND HENCE...POPS WILL NOT BE INCLUDED.
ACROSS THE PLATEAU HOWEVER...ELEVATED MOISTURE LEVELS WILL HANG ON
JUST A BUT LONGER SO I MAY INCLUDE JUST A 20 POP. THAT 20 POP WILL
CONTINUE INTO SUNDAY AS WELL.
FOR THE NEAR TERM TEMPS...NOT TOO MUCH DEVIATION VERSUS THE MODEL
GUIDANCE. WILL GO JUST A TOUCH HIGHER ON THE MONDAY MORNING LOWS.
IN THE EXTENDED FCST...THE WESTERLIES WILL CONTINUE BUT WILL BE
RATHER UNEVENTFUL MONDAY AND TUESDAY. BUT...ON THURSDAY...ANOTHER
COLD FRONT WILL REACH OUR AREA. THIS ONE LOOKS A BIT STRONGER WITH
COOLER AIR IN ITS WAKE. COULD BE A DESCENT RAIN PRODUCER AND THERE
COULD BE ENOUGH INSTABILITY ON BOTH WEDNESDAY AND THURSDAY
AFTERNOONS SO AS TO PRODUCE A FEW STRONG STORMS. OTW...FOR
NOW...MODELS LEAN TOWARD A DRIER AND COOLER FRIDAY OF NEXT WEEK
BEHIND THE FROPA.
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 71 88 68 83 / 20 50 20 10
CLARKSVILLE 68 85 63 81 / 20 50 10 10
CROSSVILLE 65 84 66 79 / 20 50 30 20
COLUMBIA 70 89 68 84 / 20 50 20 10
LAWRENCEBURG 68 89 67 85 / 20 50 20 20
WAVERLY 69 86 64 82 / 20 50 20 10
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1254 PM CDT FRI SEP 5 2014
.AVIATION...
EXPECT TO SEE SIMILAR CONDITIONS THAT WE`VE SEEN FOR THE PAST
SEVERAL DAYS. PRIMARILY VFR OUTSIDE ANY SCT CONVECTION. PRECIP
TRENDS ALSO ABOUT THE SAME...SCT ACTIVITY DEVELOPING NEAR/OFF
COAST IN EARLY MORNING THEN TRANSITIONING INLAND LATE MORNING AND
AFTERNOON WITH DAYTIME HEATING. PRECIP TAPERS OFF IN THE EARLY
EVENING WITH LOSS OF HEATING. 47
&&
.PREV DISCUSSION... /ISSUED 1030 AM CDT FRI SEP 5 2014/
AN UPPER AIR ANALYSIS SHOWED A HIGH PRESSURE RIDGE EXTENDING FROM
THE MID ATLANTIC INTO THE LOWER TEXAS COAST. THE WATER VAPOR ALSO
SHOWED AN UPPER LOW OVER SOUTHERN LA DRIFTING WESTWARD..ALTHOUGH
THERE WAS ANOTHER UPPER LEVEL HIGH PRESSURE AREA OVER AR DRIFTING
SOUTHWESTWARD. THE 12Z SOUNDINGS SHOWED AN UNCAPPED AIRMASS WITH
PW/S FROM 1.8 TO 2 INCHES...ALTHOUGH DRIER AIR ASSOCIATED WITH THE
HIGH OVER AR WAS WORKING ITS WAY INTO THE AREA FROM THE NORTHEAST.
THIS SHOULD BE OFFSET LATER TODAY BY THE MOIST AIRMASS OVER
SOUTHERN LA WORKING ITS WAY WESTWARD. CAPE VALUES AT KLCH AND KCRP
RANGED FROM 3000 TO 3500...WHILE THE DRIER AIRMASS AT KSHV HAD A
CAPE OF 1600. ISOLATED STRONG STORMS ARE POSSIBLE WITH THE MAIN
THREAT STRONG WINDS AND LOCALLY HEAVY DOWNPOURS. OF THE HIGH
RESOLUTION MODELS...THE ARW INITIALIZED FAIRLY WELL. A CONSENSUS
OF THE ARW AND HRRR INDICATES SCATTERED COVERAGE OVER MOST OF THE
INLAND AREAS LATER TODAY.
TWEAKED THE RAIN CHANCES AND HUMIDITY GRIDS TODAY. ALSO UPDATED
THE HAZARDOUS WEATHER OUTLOOK TO INCLUDE THE POTENTIAL FOR
ISOLATED STRONG STORMS TODAY...SATURDAY...AND SUNDAY. 40
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 95 74 95 74 94 / 30 10 40 20 30
HOUSTON (IAH) 93 75 92 75 93 / 30 10 40 20 30
GALVESTON (GLS) 90 81 90 80 89 / 40 10 30 20 30
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
353 PM CDT FRI SEP 5 2014
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 353 PM CDT FRI SEP 5 2014
AT 3 PM...A STRONG CANADIAN COLD FRONT EXTENDED FROM NEW BERLIN
WISCONSIN SOUTHWEST TO WEATHERFORD OKLAHOMA /KOJA/. TEMPERATURE
AHEAD OF THIS COLD FRONT RANGED FROM THE MID 80S TO MID 90S WITH
DEW POINTS IN THE 70S. MEANWHILE BEHIND THIS COLD FRONT...
TEMPERATURES WERE IN THE 60S AND 70S WITH DEW POINTS IN THE 50S.
A BAND OF 900 TO 700 MB FRONTOGENESIS IS GENERATING A BAND OF
SHOWERS ACROSS PARTS OF NORTHEAST IOWA AND SOUTHWEST WISCONSIN. IN
ADDITION WITH THE RAP SHOWING MOST UNSTABLE CAPES UP TO 500 J/KG
AND SOME SLANTWISE CONVECTION...KEPT ISOLATED THUNDERSTORMS IN THE
FORECAST. WITH FAIRLY LIMITED MOST UNSTABLE CAPES AND UNFAVORABLE
0-3 KM OR 0-6 KM SHEAR...NOT ANTICIPATING ANY OF THESE
THUNDERSTORMS TO BECOME SEVERE. MEANWHILE FURTHER NORTHWEST
ACROSS SOUTHEAST MINNESOTA...700 TO 500 MB FRONTOGENESIS IS
PRODUCING ANOTHER BAND OF SHOWERS.
FOR EARLY THIS EVENING...THE RAP SHOWS THAT THE 2 BANDS OF
FRONTOGENESIS WILL MOVE QUICKLY SOUTHEAST OF THE FORECAST AREA BY
06.03Z. AS THIS OCCURS...THE SHOWERS AND ISOLATED THUNDERSTORMS
WILL MOVE OUT OF THE AREA. AS A RESULT...WENT WITH A QUICK
LOWERING OF THE PRECIPITATION PROBABILITIES FROM WEST TO EAST
ACROSS SOUTHEAST MINNESOTA...NORTHEAST IOWA...AND IN WESTERN
WISCONSIN SOUTH OF INTERSTATE 90 BETWEEN 05.23Z AND 06.03Z. IN
ADDITION TO THIS...THE CLOUDS SHOULD BE QUICKLY ON THE DECREASE.
FOR LATE TONIGHT...THE BUFKIT SOUNDINGS SHOW A SHALLOW LAYER /A
COUPLE OF HUNDRED FEET/ OF LIGHT WINDS WITH 10 TO 20 KNOTS ABOVE
300 FEET. THESE WINDS SHOULD MAKE IT UNFAVORABLE FOR THE
DEVELOPMENT OF FOG TONIGHT.
ON SATURDAY...BUFKIT SOUNDINGS SHOW VERY STEEP 900 TO 750 MB LAPSE
RATES /9-10 C/KM/ ACROSS THE AREA. THIS WILL ALLOW THE WIND GUSTS
TO CLIMB INTO THE 10 TO 20 KNOT RANGE. IN ADDITION...THIS WILL
ALLOW DRIER AIR FROM ALOFT TO MIX TO THE SURFACE. AS A RESULT...
LOWERED THE DEW POINTS INTO THE 45 TO 50 DEGREE RANGE. THIS STILL
MAY BE ON THE HIGH SIDE...BUT THE TREND IS IN THE RIGHT DIRECTION.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 353 PM CDT FRI SEP 5 2014
FROM LATE SATURDAY NIGHT INTO SUNDAY MORNING...THE LAYER OF LIGHT
WINDS ONCE AGAIN LOOK VERY SHALLOW. IN ADDITION...THE DEW POINTS
ARE SHOWING A SLOW RECOVERY. AS A RESULT...UNCERTAIN OF WHETHER
ANY VALLEY FOG WILL OCCUR OR NOT. SO JUST WENT WITH PATCHY FOG IN
THE RIVER VALLEY AND THE CRANBERRY BOGS OF CENTRAL WISCONSIN.
ON SUNDAY AFTERNOON...BUFKIT SOUNDINGS SHOW VERY STEEP 900 TO 750 MB
LAPSE RATES /8-10 C/KM/ ACROSS THE AREA. THIS WILL ALLOW DRIER
AIR FROM ALOFT TO MIX TO THE SURFACE. AS A RESULT...LOWERED THE
DEW POINTS INTO THE 45 TO 50 DEGREE RANGE.
FROM MONDAY AFTERNOON THROUGH WEDNESDAY...THE MODELS CONTINUE TO
SHOW THAT A SERIES OF SHORT WAVE TROUGHS WILL MOVE THROUGH THE
REGION. DUE TO RUN TO RUN MODEL INCONSISTENCIES...THE TIMING OF
THESE WAVES IS STILL A BIT UNCERTAIN...SO KEPT BROAD BRUSHED THE
PRECIPITATION CHANCES DURING THIS TIME FRAME. WITH MOST UNSTABLE
CAPES LESS THAN 750 J/KG...KEPT THE THUNDERSTORM CHANCES AS
ISOLATED. WHEN THE 0-3 KM TO 0-6 KM SHEAR DOES BECOME FAVORABLE
FOR THE DEVELOPMENT OF SUPERCELLS...THERE IS VERY LITTLE
INSTABILITY. AS A RESULT...NOT ANTICIPATING ANY SEVERE WEATHER.
ON WEDNESDAY NIGHT...A STRONG CANADIAN COLD FRONT WILL MOVE SOUTH
THROUGH THE FORECAST AREA. BEHIND THIS FRONT...850 MB TEMPERATURES
WILL FALL INTO THE 0 TO -4C RANGE AND REMAIN IN THIS RANGE INTO
THE WEEKEND. THIS IS NEARLY 2 STANDARD DEVIATIONS BELOW NORMAL.
IT CONTINUES TO LOOK LIKE...HIGH TEMPERATURES WILL BE AROUND 60
ON THURSDAY...AND ONLY IN THE 50S FOR FRIDAY. WHILE THERE IS
AGREEMENT IN THE ECMWF AND GFS ON THESE HIGH TEMPERATURES...THEY
ARE STILL RUNNING 10 DEGREES APART ON THE LOW TEMPERATURES FOR
THURSDAY NIGHT AND FRIDAY NIGHT. THE ECMWF HAS LOW TEMPERATURES
AROUND 40 AND THEY ARE AROUND 30 IN THE GFS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1220 PM CDT FRI SEP 5 2014
WEAK SHORTWAVE TROUGH EXITING EAST...BUT ANOTHER WILL MOVE IN FROM
THE CENTRAL PLAINS LATER THIS AFTERNOON. THIS FEATURE IS ALREADY
FIRING SHRA/TS OVER NEB...AND THIS ACTIVITY SHOULD SPREAD INTO PARTS
OF NORTHEAST IA/SOUTHWEST WI TOWARD 21Z...WITH MESO MODELS EXITING
IT ENE BY 02Z. ALL FAVORING KEEPING THIS ACTIVITY SOUTH OF KRST/KLSE
FOR NOW...BUT COULD SEE SOME RW-- ASSOCIATED WITH A FRONTOGENETIC
REGION. WILL ADD IN SOME VCSH FOR NOW.
SOME LOWER MVFR CIGS HAVE DEVELOPED IN THAT FRONTOGENETIC REGION
NORTH OF THE APPROACHING SHORTWAVE. THESE LOWER CIGS WILL LIKELY
STICK AROUND FOR THE BETTER PART OF THE AFTERNOON...ALTHOUGH SOME
DIURNAL BUMP UPWARD IS PROBABLE. THESE LOWER CLOUDS WILL EXIT LATER
THIS AFTERNOON-EARLY EVENING...WITH SKC-VFR LATER THIS EVENING INTO
FRIDAY.
AS FOR VALLEY FOG AT KLSE...BUFKIT SOUNDINGS VIA THE NAM AND RAP
KEEP A T/TD SPREAD THROUGH THE NIGHT...AND WINDS OF 10+ KTS BLOWING
BY 200 FT. POTENTIAL FOR VSBY RESTRICTIONS AT KLSE FROM FG LOOKS LOW
AS A RESULT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
338 PM CDT FRI SEP 5 2014
.TONIGHT AND SATURDAY...FORECAST CONFIDENCE IS HIGH.
CONVECTION ASSOCIATED WITH SURFACE COLD FRONT PUSHED THROUGH KENOSHA
COUNTY IN THE PAST HOUR...AND IS NOW MOVING AWAY FROM THAT AREA.
AREA OF SHOWERS AND ISOLATED THUNDERSTORMS CONTINUES TO PUSH
NORTHEAST INTO THE AREA FROM EASTERN IOWA AND FAR NORTHWEST
ILLINOIS. THIS IS ASSOCIATED WITH LOW LEVEL FRONTOGENESIS RESPONSE
FIELDS AND UPPER DIVERGENCE FROM RIGHT REAR QUADRANT OF 250 MB JET
STREAK.
THESE FEATURES SHOULD SLIDE ACROSS A GOOD PORTION OF THE AREA INTO
EARLY THIS EVENING. SO...BROUGHT IN HIGHER POPS FOR SHOWERS AND
ISOLATED STORMS ACROSS A GOOD PORTION OF THE AREA. THIS IS SUPPORTED
BY LATEST HRRR RUN AND WRF NMM/ARW MODELS. WENT WITH MORE SCATTERED
TO NUMEROUS SHOWER WORDING...AS THEY WILL HAVE TO BATTLE DRYING LOW
LEVEL AIR ACROSS THE AREA.
PRECIPITATION SHOULD EXIT THE AREA BY MIDDLE EVENING...WITH SKIES
BECOMING MOSTLY CLEAR FROM WEST TO EAST LATER TONIGHT INTO SATURDAY
MORNING. HIGH PRESSURE SLIDING EAST TOWARD THE REGION WILL BRING
QUIET WEATHER INTO SATURDAY. LOWS TONIGHT SHOULD DROP INTO THE LOWER
50S INLAND...WITH MILDER READINGS NEAR THE LAKE. HIGHS SHOULD REACH
THE LOWER 70S ON SATURDAY.
.SATURDAY NIGHT THROUGH MONDAY - CONFIDENCE HIGH...
ALL MODELS SHOW HIGH PRESSURE CENTERED OVER THE CENTRAL PLAINS
SATURDAY NIGHT EXPANDING OVER THE GREAT LAKES SUNDAY AND CONTINUE TO
BUILD NORTHEASTWARD THROUGH MONDAY. THIS WILL BRING MOSTLY CLEAR
SKIES..LIGHT WINDS...DRIER CONDITIONS. HIGH TEMPERATURES NEAR
NORMAL...IN THE MID 70S. GOOD RADIATIONAL COOLING CONDITIONS WILL
ALLOW OVERNIGHT LOW TEMPERATURES TO DROP SLIGHTLY BELOW NORMAL...LOW
50S.
.MONDAY NIGHT THROUGH THURSDAY - CONFIDENCE...MEDIUM
LOW PRESSURE DEVELOPING WEST THE AREA MONDAY NIGHT AND APPROACHING
THE REGION TUESDAY CREATES A SOUTHWESTERLY FLOW AND SIGNIFICANT
MOISTURE ADVECTION WITH CHANCE OF SHOWERS DEVELOPING MONDAY NIGHT
AND INCREASING TUESDAY. SURFACE LOW PRESSURE DEEPENING OVER THE AREA
TUESDAY NIGHT AND SLOWLY MOVING NORTHEASWARD AND DEEPENING ACROSS
THE GREAT LAKES REGION THROUGH THURSDAY. THIS LOW COMBINED WITH
MULTIPLE UPPER LEVEL SHORT WAVES SHOULD KEEP UNSETTLED WEATHER AND A
CHANCE OF RAINSHOWERS AND SOME THUNDERSTORMS THROUGHOUT THE MIDDLE
OF NEXT WEEK.
.THURSDAY NIGHT AND FRIDAY - CONFIDENCE...MEDIUM
STRONG HIGH PRESSURE EXPECTED TO DEVELOP OVER THE CENTRAL AND
NORTHERN PLAINS AND LOW PRESSURE CENTER REMAINING OVER SOUTHEAST
CANADA WILL PRODUCE NORTHWEST FLOW ACROSS WISCONSIN. THIS WILL BRING
DRIER BUT SIGNIFICANTLY COOLER AIR TO THE AREA FRIDAY AND INTO THE
WEEKEND. THURSDAY NIGHT LOWS IN THE 40S. HIGH TEMPERATURES FRIDAY
MAY STRUGGLE TO REACH 60.
&&
.AVIATION/00Z TAFS/...
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED UNTIL
AROUND 03Z SATURDAY ACROSS TAF SITES...AS A TROUGH OF LOW PRESSURE
MOVES THROUGH THE REGION. CEILINGS SHOULD BECOME VFR CATEGORY DURING
THIS TIME. MODERATE NORTHWEST WINDS WITH SOME GUSTS TO AROUND 15
KNOTS WILL LINGER UNTIL AROUND 00Z SATURDAY.
HIGH PRESSURE MOVING EAST TOWARD THE REGION LATER TONIGHT INTO
SATURDAY WILL BRING QUIET WEATHER TO THE AREA. SKIES SHOULD BECOME
MOSTLY CLEAR BY LATER TONIGHT OR EARLY SATURDAY. WINDS WILL BECOME
LIGHT OUT OF THE NORTH TO NORTHWEST DURING THIS TIME.
&&
.MARINE...
NORTHWEST WINDS OF 10 TO 15 KNOTS WILL LINGER UNTIL AROUND 00Z
SATURDAY. MAY SEE A FEW GUSTS TO 20 KNOTS. WINDS WILL DIMINISH
TONIGHT WITH WEAKENING PRESSURE GRADIENT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TONIGHT/SATURDAY AND AVIATION/MARINE...WOOD
SATURDAY NIGHT THROUGH FRIDAY...SLB
AREA FORECAST DISCUSSION...CORRECTED AVIATION
NWS LA CROSSE WI
1220 PM CDT FRI SEP 5 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 320 AM CDT FRI SEP 5 2014
THE MAIN FOCUS IN THE SHORT TERM IS ON THE PRECIPITATION/TEMPERATURE/DEW
POINT TRENDS AS A COLD FRONT MOVES THROUGH THE REGION.
CURRENTLY...A SURFACE COLD FRONT EXTENDS FROM THE WESTERN UP OF
MICHIGAN DOWN THROUGH SOUTHWEST WISCONSIN AND SOUTH CENTRAL IOWA.
THE AIR MASS BEHIND THIS FRONT IS MUCH COOLER AND LESS HUMID WITH
TEMPERATURES DROPPING FROM THE UPPER 70S TO THE MID 50S AND DEW
POINTS GOING FROM THE MID 70S TO THE UPPER 40S. WHILE THE
ENVIRONMENT IN THE WARM SECTOR IS CAPPED OFF...SOME SLOPING LOW
LEVEL FRONTOGENESIS IS BEING AIDED BY A MID LEVEL TROUGH DIGGING
ACROSS NORTH DAKOTA/NORTHERN MINNESOTA AND HAS PRODUCED A BAND OF
CONVECTION ACROSS THE NORTHERN HALF OF IOWA. THIS RAIN WILL TRACK
TO THE NORTHEAST/EAST THIS MORNING BUT LIKELY WEAKEN AS IT LEAVES
THE DEEPER FORCING IN CENTRAL IOWA. THE 05.07Z RAP SHOWS THAT THE
0-3KM MUCAPE DROPS QUITE A BIT ONCE YOU REACH THIS
PRECIPITATION AND VERTICAL SHEAR PROFILES SHOW ONLY ABOUT 20-30KTS
OF 0-6KM SHEAR WITH MUCH OF IT AROUND 900-750MB. BASED ON
THIS...AM NOT EXPECTING MUCH IN THE WAY OF SEVERE WEATHER BUT
THAT THERE WILL BE A PERIOD OF LIGHT TO MODERATE
RAINFALL...PARTICULARLY ACROSS NORTHEAST IOWA AND FAR SOUTHWEST
WISCONSIN.
CLOUD COVER WILL LIKELY LINGER THROUGH MUCH OF THE DAY AS ANOTHER
MID LEVEL SHORT WAVE TROUGH TRACKS TO THE EAST FROM EASTERN
COLORADO/WESTERN NEBRASKA ON THROUGH IOWA TODAY. 06.00Z NAM/GFS
FORECAST SOUNDINGS SHOW A SATURATING MID LEVEL LAYER WITH DRY AIR
STUCK UNDERNEATH IT. WHILE THE FOCUS APPEARS TO MAINLY BE ACROSS
THE SOUTHERN HALF OF IOWA INTO TONIGHT...THE 05.00Z NAM/GFS/ECMWF
DO HINT AT SOME LIGHT QPF MAKING IT INTO THE REGION. CONFIDENCE IS
NOT HIGH ENOUGH RIGHT NOW WITH WHAT WILL WIN OUT IN THIS BATTLE OF
DRY AIR...SO HAVE KEPT THE FORECAST DRY INTO TONIGHT FOR THE TIME
BEING.
OTHERWISE...HIGH TEMPERATURES HAVE ALREADY BEEN HIT FOR THE DAY AS
THEY WILL DROP INTO THIS MORNING AND THEN MAKE A SMALL DIURNAL
BUMP THIS AFTERNOON BEFORE DROPPING QUICKLY TONIGHT. LOW LEVEL
WINDS LOOK LIKE THEY SHOULD BE STRONG ENOUGH TO KEEP ANY VALLEY
FOG FROM FORMING...BUT WILL HAVE TO MONITOR THE CONDITIONS INTO
TONIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 320 AM CDT FRI SEP 5 2014
FAIRLY QUIET EXTENDED PERIOD WITH THE COOLER TEMPERATURES THE MAIN
STORY. THE COOLEST PERIOD APPEARS TO BE THIS WEEKEND AS +6C TO +8C
850MB AIR SITS OVER THE REGION BEFORE WARMER AIR GETS ADVECTED IN
ON THE BACK SIDE OF THE RIDGE EARLY NEXT WEEK. THE NEXT CHANCES
FOR PRECIPITATION ARE ON MONDAY INTO THURSDAY AS A MID LEVEL
SHORT WAVE TROUGH MOVES THROUGH THE REGION. NOT MUCH INSTABILITY
TO WORK WITH AS THE 05.00Z GFS/ECMWF SHOW LESS THAN 1000 J/KG OF
0-3KM MUCAPE AROUND THE REGION SO DO NOT EXPECT MUCH IN THE WAY
OF WIDESPREAD THUNDERSTORMS...PARTICULARLY ANYTHING CONSIDERED
SEVERE.
A MORE SIGNIFICANT COLD PUSH LOOKS LIKE IT WILL MOVE IN ON
THURSDAY WITH 850MB TEMPERATURES DROPPING BELOW 0C. THIS WILL
LIKELY LEAD TO SOME LOW TEMPERATURES DIPPING INTO THE 30S GOING
INTO FRIDAY MORNING AND THE POTENTIAL FOR SOME FROST IN THE
TYPICAL LOW/COLD BOG AREAS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1220 PM CDT FRI SEP 5 2014
WEAK SHORTWAVE TROUGH EXITING EAST...BUT ANOTHER WILL MOVE IN FROM
THE CENTRAL PLAINS LATER THIS AFTERNOON. THIS FEATURE IS ALREADY
FIRING SHRA/TS OVER NEB...AND THIS ACTIVITY SHOULD SPREAD INTO PARTS
OF NORTHEAST IA/SOUTHWEST WI TOWARD 21Z...WITH MESO MODELS EXITING
IT ENE BY 02Z. ALL FAVORING KEEPING THIS ACTIVITY SOUTH OF KRST/KLSE
FOR NOW...BUT COULD SEE SOME RW-- ASSOCIATED WITH A FRONTOGENETIC
REGION. WILL ADD IN SOME VCSH FOR NOW.
SOME LOWER MVFR CIGS HAVE DEVELOPED IN THAT FRONTOGENETIC REGION
NORTH OF THE APPROACHING SHORTWAVE. THESE LOWER CIGS WILL LIKELY
STICK AROUND FOR THE BETTER PART OF THE AFTERNOON...ALTHOUGH SOME
DIURNAL BUMP UPWARD IS PROBABLE. THESE LOWER CLOUDS WILL EXIT LATER
THIS AFTERNOON-EARLY EVENING...WITH SKC-VFR LATER THIS EVENING INTO
FRIDAY.
AS FOR VALLEY FOG AT KLSE...BUFKIT SOUNDINGS VIA THE NAM AND RAP
KEEP A T/TD SPREAD THROUGH THE NIGHT...AND WINDS OF 10+ KTS BLOWING
BY 200 FT. POTENTIAL FOR VSBY RESTRICTIONS AT KLSE FROM FG LOOKS LOW
AS A RESULT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM....HALBACH
AVIATION.....RIECK
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1129 AM CDT FRI SEP 5 2014
.UPDATE...
COLD FRONT SLIDING THROUGH THE FAR SOUTHEAST COUNTIES...AND WILL
EXIT THE AREA EARLY THIS AFTERNOON. SOME LIGHT SHOWERS MAY AFFECT
PARTS OF SOUTH CENTRAL WISCONSIN OVER THE NEXT HOUR OR TWO...AS
500 MB VORTICITY MAXIMUM SHIFTS THROUGH WISCONSIN. THEY WERE
SHOWING A DECREASING TREND...AS THEY MOVE INTO AN AREA OF COLD AIR
ADVECTION WITH DRIER LOW LEVEL AIR.
OTHER LIGHT SHOWERS ARE POSSIBLE THROUGH THE AFTERNOON...WITH LOW
LEVEL FRONTOGENESIS RESPONSE FIELDS AND UPPER DIVERGENCE FROM
RIGHT REAR QUADRANT OF 250 MB JET STREAK. THE SOUTHEAST COUNTIES
WOULD HAVE THE BEST CHANCES...THOUGH MAY SEE MORE MOVE TOWARD THE
WESTERN COUNTIES LATER IN THE AFTERNOON WITH INCREASING UPPER
DIVERGENCE. FOR NOW...KEPT POPS GOING IN THE SOUTHEAST AND FAR
SOUTHERN COUNTIES...AND DRY ELSEWHERE THIS AFTERNOON.
SHOWERS WILL HAVE TO BATTLE DRYING LOW LEVEL AIR ACROSS THE
AREA...SO SOME UNCERTAINTY WITH AREAL COVERAGE. MEAN LAYER CAPES
SHIFTING SOUTHEAST OF THE AREA WITH COLD FRONT. AREA FORECAST
SOUNDINGS SHOWING ELEVATED CAPE WEAKENING DURING THE
AFTERNOON...SO WENT WITH ISOLATED THUNDER WORDING.
SHOULD SEE SOME CUMULUS DEVELOPMENT THIS AFTERNOON WHICH WOULD
FILL IN CLOUD FREE AREAS. TEMPERATURES SHOULD REACH THE MID 70S
ACROSS MOST OF THE AREA...WITH LOWER 80S LINGERING IN THE FAR
SOUTHEAST.
&&
.AVIATION/18Z TAFS/...
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE POSSIBLE THROUGH
THE AFTERNOON AND EVENING HOURS...AS A TROUGH OF LOW PRESSURE
MOVES THROUGH THE REGION. CEILINGS SHOULD BECOME VFR CATEGORY WITH
DIRUNAL CUMULUS AND MIDDLE LEVEL CLOUDS EXPECTED. MODERATE WEST
WINDS WILL VEER NORTHWEST AS WELL...WITH SOME GUSTS UP TO 18
KNOTS.
HIGH PRESSURE MOVING EAST TOWARD THE REGION TONIGHT INTO SATURDAY
WILL BRING QUIET WEATHER TO THE AREA. SKIES SHOULD BECOME MOSTLY
CLEAR BY LATER TONIGHT. MAY SEE SOME DIURNAL CUMULUS ON SATURDAY.
WINDS WILL BECOME LIGHT OUT OF THE NORTH TO NORTHWEST DURING THIS
TIME.
&&
.MARINE...
WEST WINDS OF 10 TO 15 KNOTS WILL VEER NORTHWEST BY EARLY THIS
AFTERNOON. MAY SEE A FEW GUSTS TO 20 KNOTS. WINDS WILL DIMINISH
TONIGHT WITH WEAKENING PRESSURE GRADIENT.
&&
.PREV DISCUSSION... /ISSUED 305 AM CDT FRI SEP 5 2014/
TODAY...FORECAST CONFIDENCE IS MEDIUM.
THE MAIN ISSUE FOR TODAY IS THE ARRIVAL OF A STRONG COLD FRONT EARLY
THIS MORNING...EXITING EAST OF MILWAUKEE BY LATE MORNING. AN AREA
OF WEAKENING CONVECTION OVER IOWA EARLY THIS MORNING IS BEING PICKED
UP BY THE HRRR AND TRACKED ACROSS THE FORECAST AREA THIS
MORNING...MOSTLY BEFORE 8 AM. THE HRRR ALSO SUGGESTS INTENSIFICATION
AND EXPANSION. THIS ACTIVITY IS FOCUSED ALONG THE H8 COLD
FRONT...WHICH IS POST FRONTAL OF THE SFC FRONT. THE CONCERN IS IT
MAY CATCH UP WITH THE SFC FRONT OVER OUR WRN CWA THIS MORNING AND
BECOME MORE SFC BASED. INSTABILITY IS PRETTY HIGH ACROSS THE AREA
RIGHT NOW...SO WILL HAVE TO WATCH TRENDS VERY CLOSELY. THERE IS A
DISTINCT LACK OF MID AND UPPER LEVEL SUPPORT AND DEEP LAYER SHEAR IS
RATHER WEAK. WILL HANG ONTO A CHANCE FOR STORMS UNTIL THE FRONT
EXITS.
THEN SOME MID LEVEL FORCING FROM AN APPROACHING SHORT WAVE COULD
RESULT IN SOME INCREASING SHOWERS SHOWERS AND ISOLATED THUNDERSTORMS
ACROSS THE SOUTHEAST THIS AFTERNOON AND INTO THE EVENING HOURS. THIS
WILL ALL BE POST FRONTAL WITH A DECENT RIGHT REAR UPPER JET QUADRANT
HELPING TO SUPPORT DECENT 700-600MB FRONTOGENESIS. THE MAIN
QUESTION IS WHETHER THERE/LL BE ENOUGH DEEP MOISTURE LEFT TO SUPPORT
SHOWERS. SOME OF THE MODELS SCOUR OUT THE RAIN ONCE THE FRONT
EXITS...OTHERS DO THE POST FRONTAL GIG...SO WILL HANG ONTO POPS SE.
COOLER AND DRIER AIR WILL CONTINUE TO OVERSPREAD THE AREA AS THE DAY
PROGRESSES.
TONIGHT...FORECAST CONFIDENCE IS HIGH.
OTHER THAN SOME LINGERING EVENING SHOWERS POSSIBLE IN THE
SOUTHEAST...THE COOLER...DRIER TREND WILL CONTINUE. SKIES WILL
GRADUALLY CLEAR WITH LOWS DIPPING INTO THE LOWER 50S OVER ALL BUT
THE SOUTHEAST. THE CLOUDS CLEARING LATER ACROSS THE SOUTHEAST WILL
KEEP TEMPS UP A BIT HIGHER.
SATURDAY AND SUNDAY - CONFIDENCE...MEDIUM
HIGH PRESSURE IN THE CENTRAL PLAINS SATURDAY WILL EXPAND ACROSS THE
GREAT LAKES SUNDAY. NORTHWEST WINDS AND THERMAL TROUGH LINGERS THROUGH
SATURDAY EVENING. SUBTLE MODIFICATION FOR SUNDAY AS 850 TEMPS MODIFY
ONLY SLIGHTLY. LIGHT WIND REGIME WITH SURFACE HIGH WELL IN PLACE AND
GRADIENT WEAK.
MONDAY - CONFIDENCE...MEDIUM
MODELS SHOW 500 MILLIBAR TROUGH APPROACHING INTO IA/MN BY END OF THE
DAY. 850 JET AXIS REMAINS WEST AND LIKE THE DRY LOOK FOR SRN WI.
WITH HIGH TO THE EAST THE FLOW WILL BECOME DECIDEDLY FROM THE
SOUTH...SO GRADUAL MOISTURE ADVECTION THOUGH BEST PUSH OF THIS HOLDS
OFF TO OUR WEST DURING THE DAY.
MONDAY NIGHT AND TUESDAY - CONFIDENCE...MEDIUM
BETTER MOISTURE ADVECTION THIS PERIOD THOUGH LLJ PROGGD BY BOTH
THE GFS AND ECMWF TO COLLAPSE TO OUR SOUTH. BUT THERE IS SOME
MOISTURE ADVECTION WITH THE INFLUENCE OF THE SHORTWAVE TROUGH. 00Z
ECMWF SHOWS THE LEAST QPF WITH THIS SYSTEM WHILE THE GFS AND GEM
SHOW A BIT MORE OF A NORTHERN MAX ACROSS OUR AREA, ALL MODELS
SUGGEST BEST CONVECTION WILL BE FURTHER SOUTH SHIFTING FROM THE
CENTRAL PLAINS INTO THE MID MISSISSIPPI VALLEY. OVERALL SURFACE
PATTERN WEAK THOUGH INCREASED FORCING VIA UPPER WAVE AND MORE
MOISTURE WILL LEAD TO MAINTAINING THE TRENDS OF THE ALLBLEND POPS.
WEDNESDAY AND THURSDAY - CONFIDENCE...LOW
WHILE DETAILS ARE YET TO GET WORKED OUT...THE GENERAL IDEA OF THE
GFS AND ECMWF IS TO TAKE AN ORGANIZING LOW PRESSURE SYSTEM FROM
VCNTY OF THE CNTRL PLAINS INTO THE EASTERN LAKES. THE TREND IS FOR
A SOUTHERN TRACK WHICH KEEPS US ON THE COOL SIDE WITH A GREATER
LIKELIHOOD FOR A FALL-LIKE STEADIER RAIN SETUP THOUGH
TIMING...TRACK AND STRENGTH OF LOW STILL VARIABLE AMONGST THE
MODELS.
AVIATION/12Z TAFS/...LOOK FOR VFR CONDITIONS THROUGH THE TAF PERIOD.
A COLD FRONT WILL SWEEP THROUGH MADISON AROUND 11-12Z THIS MORNING
AND REACH MILWAUKEE AROUND 14Z. WE COULD SEE SHOWERS AND THUNDERSTORMS
EXPAND ALONG THE FRONT THIS MORNING AS SOME WEAK CONVECTION MOVES
NORTHEAST OUT OF IOWA. CONDITIONS COULD BRIEFLY DROP TO MVFR LEVELS
IN ANY STRONGER STORMS. MORE POST FRONTAL SHOWERS AND STORMS ARE
POSSIBLE ACROSS THE SOUTHEAST WISCONSIN TAF SITES LATER THIS AFTERNOON
AND INTO THE EVENING AS A WEAK MID LEVEL WAVE MOVES BY. OTHERWISE...
LOOK FOR CLEARING SKIES FROM NORTHWEST TO SOUTHEAST OVERNIGHT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...WOOD
TODAY/TONIGHT AND AVIATION/MARINE...DAVIS
SATURDAY THROUGH THURSDAY...COLLAR
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1035 AM MDT FRI SEP 5 2014
.UPDATE...
ISSUED AT 1022 AM MDT FRI SEP 5 2014
FOG AND LOW CLOUDS ARE NOT IN A HURRY TO DISSIPATE NEAR THE
SOUTHERN LARAMIE RANGE. SOUTH TO SOUTHEAST WINDS WILL REMAIN IN
PLACE THROUGH TODAY AND TONIGHT...KEEPING THE LOW LEVEL INVERSION
IN PLACE ALONG WITH THE THREAT FOR FOG...ESPECIALLY NEAR THE
SUMMIT BETWEEN LARAMIE AND CHEYENNE. MAY NEED A DENSE FOG ADVISORY
FOR THE SOUTHERN LARAMIE RANGE ZONES TONIGHT AND POSSIBLY
CHEYENNE.
LOTS OF SUNSHINE WEST OF THE LARAMIE RANGE THIS MORNING. THE
SUNSHINE WILL LEAD TO ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS THIS AFTERNOON. THUNDERSTORMS WILL HAVE A VERY
DIFFICULT TIME MAKING THEIR WAY EAST OF THE LARAMIE RANGE AS THEY
WILL ENCOUNTER STABLE LOW LEVEL AIR.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 231 AM MDT FRI SEP 5 2014
A COUPLE BANDS OF SHOWERS MOVING ACROSS PARTS OF THE CWA EARLY
THIS MORNING LIKELY AIDED BY AN UPPER JET MOVING NORTHEAST ACROSS
THE REGION. EXPECT THIS ACTIVITY TO MOVE OUT OVER THE NEXT SEVERAL
HOURS BEFORE REGENERATING OVER THE MTNS THIS AFTERNOON AS A WEAK
IMPULSE IN WESTERLY UPPER FLOW INTERACTS WITH SOME WEAK
INSTABILITY AND SOME UPSLOPE COMPONENT IN THE SFC WIND FLOW.
ACTIVITY WILL HAVE DIFFICULTY MAKING MUCH PROGRESS EASTWARD WITH
CAPPING OVER THE PLAINS. RATHER COOL OVER THE EASTERN PLAINS OF
THE CWA TODAY WITH MOST AREAS LIKELY STAYING IN THE 60S AS A SFC
HIGH SETTLES ACROSS THE CENTRAL PLAINS. COOL TONIGHT WITH SHOWERS
ENDING IN THE EVENING THEN BASICALLY A REPEAT PERFORMANCE SATURDAY
WITH SHOWERS AND A FEW STORMS DEVELOPING OVER THE MTNS IN THE
AFTERNOON BUT AGAIN NOT MAKING A LOT OF PROGRESS EASTWARD. ABOUT 5
TO 10 DEGREES WARMER SATURDAY WITH RETURN FLOW ON BACK SIDE OF
DEPARTING SFC HIGH. ADD ABOUT ANOTHER 5 TO 10 DEGREES FOR MAXS
SUNDAY WITH MORE OF A DOWNSLOPE FLOW AND SOME SUNSHINE. WIDELY
SCTD SHOWERS AND A FEW STORMS ONCE AGAIN INITIATING OVER THE MTNS
BUT MAKING A BIT BETTER PROGRESS OVER THE PLAINS.
.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 231 AM MDT FRI SEP 5 2014
MODEL CONSENSUS STILL POOR ON THE SYSTEM MIDWEEK. HUGE TEMPERATURE
BUST POTENTIAL WEDNESDAY AND THURSDAY DEPENDING ON WHICH MEDIUM
RANGE MODEL WINS OUT. FORECAST CHALLENGES IN THE EXTENDED DEAL
WITH MAINLY TEMPERATURES.
NORTHWEST FLOW FOR SUNDAY NIGHT WITH A WEAK SHORTWAVE MOVING
THROUGH NORTHERN WYOMING. HAVE SOME SLIGHT CHANCE POPS FOR THE
AREA SUNDAY NIGHT...MORE BASED ON WHAT THE GFS IS SHOWING. BUT
THEY SHOULD END FAIRLY QUICKLY AFTER MIDNIGHT. MONDAY LOOKS DRY
WITH GUIDANCE SHOWING MOST ALL OF THE QPF OVER COLORADO. DID KEEP
SOME LOW END CHANCE POPS FOR THE SNOWY AND SIERRA MADRE RANGES.
PRECIP REALLY DOES NOT GET INTO THE CHEYENNE CWFA UNTIL TUESDAY
AFTERNOON. BOTH THE GFS AND ECMWF HAVE POPS OUT IN CARBON COUNTY.
THIS IS WHERE MODEL GUIDANCE BEGINS TO DIVERGE.
GFS KEEPS 7000MB TEMPERATURES FAIRLY WARM TUESDAY NIGHT INTO
WEDNESDAY. TEMPERATURES STAY ABOVE FREEZING THROUGH WEDNESDAY
AFTERNOON. THE GFS DOES BRING A FRONT INTO THE AREA FROM THE
NORTH. 700MB TEMPERATURES FROM THE GFS RANGE FROM +6C TO +2C OVER
THE CWFA WEDNESDAY AFTERNOON. ECMWF ON THE OTHER HAND...HAS 700MB
TEMPERATURES OF +2C TO -2C OVER THE CWFA WEDNESDAY AFTERNOON.
WHILE THE ECMWF FORECASTS 700MB TEMPERATURES FALLING TO -6 TO -8C
THURSDAY NIGHT INTO FRIDAY...THE GFS KEEPS THE COLDER AIR NORTH
AND IS FORECASTING +10 TO +4C GRADIENT OVER WYOMING THROUGH FRIDAY
MORNING. DECIDED TO BEGIN GOING WITH THE MORE CONSISTENT
ECMWF...WHICH HAS BEEN SHOWING THIS COOL DOWN FOR THE PAST THREE
DAYS. USED HPC AND ECMWF GUIDANCE ON TEMPERATURES FOR THURSDAY AND
FRIDAY. WITH THIS FORECAST...THERE ARE GOING TO BE AREAS THAT WILL
MOST LIKELY SEE SNOW...ESPECIALLY CONVERSE/NIOBRARA COUNTIES IN
CENTRAL WYOMING. MAY STILL BE TOO WARM FOR SNOW IN THE NORTHERN
PANHANDLE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 453 AM MDT FRI SEP 5 2014
CEILINGS ARE STARTING TO COME DOWN NOW AS OF 11Z. HRRR SHOWING THE
SOUTHERN PANHANDLE...KCYS AND POSSIBLY KLAR COMING DOWN TO IFR
SHORTLY AFTER 12Z AND STAYING DOWN THROUGH AT LEAST 18Z. GENERALLY
FOLLOWED THE HRRR GUIDANCE ON FORECAST CONDITIONS THIS MORNING.
LOOKS LIKE A RETURN TO IFR THIS EVENING WITH UPSLOPING SOUTHEAST
WINDS.
&&
.FIRE WEATHER...
ISSUED AT 231 AM MDT FRI SEP 5 2014
FIRE WEATHER CONCERNS TO REMAIN LOW THROUGH THE WEEKEND WITH NON-
CRITICAL CONDITIONS EXPECTED WEATHER-WISE. SOMEWHAT COOL
CONDITIONS TODAY THEN A WARM UP OVER THE WEEKEND WITH DECREASING
CHANCES FOR RAIN.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...SML
SHORT TERM...RE
LONG TERM...CLAYCOMB
AVIATION...CLAYCOMB
FIRE WEATHER...RE