Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/04/15
AREA FORECAST DISCUSSION
NWS TUCSON AZ
950 PM MST TUE SEP 1 2015
.SYNOPSIS...AMPLE MOISTURE IN COMBINATION WITH SEVERAL DISTURBANCES
WILL MAINTAIN SCATTERED THUNDERSTORMS THROUGH SATURDAY. ISOLATED TO
SCATTERED MAINLY AFTERNOON AND EVENING THUNDERSTORMS WILL THEN
PREVAIL EARLY NEXT WEEK. EXPECT BELOW AVERAGE DAYTIME TEMPERATURES
THROUGH SATURDAY FOLLOWED BY A MODEST WARMING TREND EARLY NEXT WEEK.
&&
.DISCUSSION...KEMX WSR-88D DETECTED ISOLATED 35-55 DBZ ECHOES FROM
NEAR THE TUCSON MOUNTAINS NWWD INTO SOUTH CENTRAL PINAL COUNTY. THE
REST OF SE ARIZONA WAS VOID OF PRECIP ECHOES. THESE SHOWERS AND
THUNDERSTORMS ONGOING WEST-TO-NORTHWEST OF THE TUCSON METRO AREA
WERE AHEAD OF A REMNANT MCV/CYCLONIC CIRCULATION FEATURE APPROACHING
THE INTERNATIONAL BORDER ADJACENT SANTA CRUZ COUNTY.
BASED ON THE 02/00Z NAM12 AND SEVERAL HRRR SOLUTIONS AS WELL AS
RADAR TRENDS...HAVE MAINTAINED ISOLATED SHOWERS/TSTMS ACROSS MUCH OF
THIS FORECAST AREA THE REST OF TONIGHT INTO EARLY WED MORNING.
ADEQUATE MOISTURE IN COMBINATION WITH A MODESTLY UNSTABLE
ENVIRONMENT AND THE AFOREMENTIONED CYCLONIC CIRCULATION FEATURE
SHOULD BE SUFFICIENT TO SUPPORT AT LEAST A SLIGHT CHANCE OF
SHOWERS/TSTMS THRU DAYBREAK WED. GIVEN THE PAUCITY OF SIGNIFICANT
RAINFALL EARLIER THIS EVENING...BELIEVE THAT AMOUNTS THE REST OF
TONIGHT WILL BE CONSIDERABLY LESS THAN 24 HOURS AGO.
OTHERWISE...EXPECT MOSTLY CLOUDY SKIES ACROSS MUCH OF SE ARIZONA THE
REST OF TONIGHT. A FAIRLY ACTIVE PERIOD FOR SHOWERS/TSTMS MAY VERY
WELL BE ON TAP WED AFTERNOON/EVENING IF THE 01/12Z UNIV OF AZ WRF
NAM/GFS SOLUTIONS AND THE 02/00Z NAM12 IS REALITY. HIGH TEMPS WED
WILL AVERAGE ABOUT 2-4 DEGS F OR SO BELOW NORMAL. EVEN COOLER
DAYTIME TEMPS ARE FORECAST TO OCCUR THUR.
PLEASE REFER TO THE ADDITIONAL SECTIONS FOR FURTHER DETAIL.
&&
.AVIATION...VALID THRU 03/06Z.
ISOLATED TO SCATTERED -TSRA/-SHRA INTO WEDNESDAY MORNING...THEN
SCATTERED TO PERHAPS NUMEROUS -TSRA/-SHRA ACROSS MUCH OF SE ARIZONA
WEDNESDAY AFTERNOON AND EVENING. BRIEF MVFR CONDITIONS AND WIND
GUSTS OF 35 TO 45 KTS WILL OCCUR WITH THE STRONGER THUNDERSTORMS.
OTHERWISE...EXPECT LAYERED CLOUDS MOSTLY BETWEEN 10-15K FT AGL AND
SURFACE WIND GENERALLY LESS THAN 10 KTS INTO WEDNESDAY EVENING.
AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...EXPECT SCATTERED SHOWERS AND THUNDERSTORMS ACROSS
MUCH OF SOUTHEAST ARIZONA THROUGH SATURDAY. LOCALLY HEAVY RAINFALL
AND BRIEF GUSTY WINDS WILL ACCOMPANY THE STRONGER THUNDERSTORMS.
THEREAFTER...ISOLATED TO SCATTERED MAINLY AFTERNOON AND EVENING
THUNDERSTORMS WILL PREVAIL SUNDAY THROUGH TUESDAY. THE BEST CHANCE
OF THIS ACTIVITY WILL BE ACROSS GREENLEE...GRAHAM AND COCHISE
COUNTIES EAST OF TUCSON. DAYTIME TEMPERATURES WILL BE BELOW SEASONAL
AVERAGES DURING THE NEXT SEVERAL DAYS FOLLOWED BY A MODEST WARMING
TREND EARLY NEXT WEEK.
&&
.PREV DISCUSSION /232 PM MST/...A DISTURBANCE EMBEDDED IN THE
SOUTHWESTERLY FLOW ALOFT WILL HELP ENHANCE THUNDERSTORM ACTIVITY
WEDNESDAY INTO THURSDAY. MODELS CONTINUED TO SUGGEST THAT A SYSTEM
APPROACHING THE SOUTHERN TIP OF BAJA WILL HELP PUSH DEEPER MOISTURE
BACK INTO THE AREA BY THE WEEKEND. THIS DEEPER MOISTURE WILL
MAINTAIN RAIN CHANCES THIS WEEK. OTHERWISE...EXPECT COOLER HIGH
TEMPERATURES THAN LAST WEEK WITH READINGS REMAINING BELOW NORMAL THE
NEXT FEW DAYS.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
903 PM MDT THU SEP 3 2015
.UPDATE...
ISSUED AT 855 PM MDT THU SEP 3 2015
CONVECTION IS ALL BUT FINISHED ACROSS THE URBAN CORRIDOR AND
MOUNTAINOUS AREAS WITH SHOWERS MOVING NORTHEAST ACROSS THE
REMAINING AREAS. THESE SHOULD FINISH BY OR SHORTLY AFTER MIDNIGHT.
OTHER THAN THAT THINGS SHOULD BE FAIRLY QUIET. HRRR AND RAP
SHOWING SOME PRECIPITATION APPROACHING THE SOUTHWEST REACHES OF
THE CWA BY MID MORNING WITH ALL AREAS HAVING A THREAT OF
CONVECTIVE PRECIPITATION DURING THE AFTERNOON AND EVENING.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 152 PM MDT THU SEP 3 2015
SATELLITE SHOWING INCREASING COVERAGE OF SHOWERS AND
THUNDERSTORMS OVER THE REGION WITH THE INCOMING DISTURBANCE AND
ASSOCIATED ENERGY FROM THE SW. INCREASED MOISTURE INTO THE REGION
HELPED TO BRING PW VALUES BACK UP CLOSE TO 1 INCH WITH ENOUGH
UPPER LEVEL ENERGY TO SUSTAIN STORMS THROUGH THE AFTERNOON. BEHIND
THE DISTURBANCE THERE IS CLEARING THAT WILL HELP TO BRING PARTLY
CLOUDY SKIES OVERNIGHT AND TEMPERATURES BACK INTO THE 50S.
FOR TOMORROW THE UPPER LEVEL JET WILL MOVE OVER THE STATE ALONG
WITH ANOTHER DISTURBANCE THAT WILL BRING ANOTHER ROUND OF
AFTERNOON STORMS. INCREASED MOISTURE FROM THE SOUTH COMBINED WITH
UPPER LEVEL FORCING FROM THE PREFERABLE JET STREAK REGION
THUNDERSTORMS WILL BE POSSIBLE IN THE MOUNTAINS AND HIGHER
FOOTHILLS WITH A SLIGHT CHANCE OVER THE PLAINS. TEMPERATURES WILL
BE SLIGHTLY WARMER THEN TODAY WITH HIGHS IN THE UPPER 80S.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 152 PM MDT THU SEP 3 2015
SOUTHWEST FLOW ALOFT WILL REMAIN OVER COLORADO FRIDAY AND SATURDAY.
ANOTHER WAVE EMBEDDED IN THE FLOW WILL MOVE ACROSS THE STATE FRIDAY.
TIMING LOOKS TO BE A LITTLE LATER IN THE DAY...SO IT APPEARS THE
BEST CHANCE FOR SHOWERS AND STORMS WILL BE DURING THE EARLY EVENING
HOURS. AFTER DRYING EARLY FRIDAY...AIRMASS WILL MOISTEN UP AGAIN
WITH PRECIPITABLE WATER VALUES CLIMBING TO AROUND AN INCH OVER THE
FRONT RANGE AND EASTERN PLAINS. THE WAVE WILL BE QUICK TO MOVE
THROUGH...SO THE THREAT FOR HEAVY RAIN WILL BE LOW. INCREASED POPS
FOR THIS SYSTEM FRIDAY EVENING. ON SATURDAY...MODELS VARY ON THE
AMOUNT OF MOIST OVER THE AREA...BUT ENOUGH SHOULD BE AROUND FOR MORE
AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS. BEST CHANCE LOOKS
TO BE OVER THE HIGHER TERRAIN.
AN UPPER LEVEL LOW WILL MOVE ACROSS THE NORTHERN ROCKIES ON SUNDAY.
THIS WILL CAUSE FLOW ALOFT TO TURN WESTERLY AND PUSH A WEAK COLD
FRONT THROUGH NORTHEAST COLORADO. TEMPERATURES WILL ONLY BE FEW
DEGREES COOLER BEHIND IT. AIRMASS WILL BE DRY AND WILL KEEP THE
FORECAST DRY. THE GFS AND ECMWF SHOW A LITTLE QPF OVER FAR NORTHEAST
COLORADO LATE SUNDAY NIGHT AND EARLY MONDAY DUE TO THE JET. AIRMASS
MAY BE TOO DRY FOR PRECIPITATION THOUGH. WILL KEEP SILENT POPS IN
DURING THIS TIME FRAME.
WESTERLY FLOW ALOFT WILL REMAIN OVERHEAD MONDAY. THIS WESTERLY FLOW
MAY BRING BREEZY CONDITIONS AT TIMES OVER THE HIGHER TERRAIN. THIS
COMBINED WITH THE DRY AIRMASS WILL ELEVATED THE FIRE DANGER.
ANOTHER TROUGH WILL PASS NORTH OF COLORADO AND PUSH A COLD FRONT
THROUGH THE AREA LATE MONDAY OR EARLY TUESDAY. SOME DIFFERENCES
AMONG THE MODELS ON HOW MUCH MOISTURE WILL BE BEHIND IT. WILL GO
WITH LOW POPS FOR TUESDAY AFTERNOON AND EVENING FOR THIS.
WEST TO NORTHWEST FLOW WILL PREVAIL BEHIND THE TROUGH FOR WEDNESDAY
AND THURSDAY. EXPECT THIS TO BRING DRY CONDITIONS WITH TEMPERATURES
NEAR NORMAL.
&&
.AVIATION...(FOR THE TAFS THROUGH 06Z FRIDAY EVENING)
ISSUED AT 855 PM MDT THU SEP 3 2015
CONVECTION FINISHED FOR THIS EVENING WITH SOUTHERLY TO DRAINAGE
WINDS EXPECTED THE REST OF THE NIGHT. ANOTHER THREAT OF SHOWERS
AND THUNDERSTORMS FRIDAY AFTERNOON.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...ET
SHORT TERM...BOWEN
LONG TERM...MEIER
AVIATION...ET
AREA FORECAST DISCUSSION
NWS PUEBLO CO
308 PM MDT WED SEP 2 2015
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 307 PM MDT WED SEP 2 2015
CONVECTION SLOWLY BEGINNING TO INCREASE ACROSS THE AREA THIS
AFTERNOON...WITH STORMS MOST NUMEROUS OVER THE SOUTHWEST MOUNTAINS
AND ALONG THE NM BORDER WHERE MOISTURE AND INSTABILITY IS GREATEST.
FOR THE REST OF THE AFTERNOON INTO THE EVENING...EXPECT CONVECTION
TO EXPAND SOMEWHAT OVER THE MOUNTAINS AND INTERIOR VALLEYS AS WEAK
UPPER WAVE AND INCREASING MID LEVEL MOISTURE MOVE INTO CO FROM NWRN
NM. HRRR SUGGESTS SOME WEAKENING STORMS TO PERHAPS REACH THE I-25
CORRIDOR AROUND KPUB AND KCOS THIS EVENING...THOUGH RATHER LOW CAPE
(200-400 J/KG) ACROSS THESE AREAS SUGGESTS STORMS WILL STAY ISOLATED
AND WEAK. A FEW STORMS WILL ALSO BE POSSIBLE ALONG THE NORTH SLOPE
OF THE RATON MESA EASTWARD ACROSS LAS ANIMAS COUNTY...WHILE
REMAINDER OF THE PLAINS SHOULD BE TOO STABLE TO SUPPORT ANY EVENING
CONVECTION. OVERNIGHT...STORMS WILL END OVER THE EASTERN HALF OF THE
AREA...WHILE A FEW -SHRA/WEAK -TSRA HANG ON ALONG THE CONTINENTAL
DIVIDE WHERE MOISTURE CONTINUES TO ADVECT NORTHWARD FROM AZ/NM.
ON THU...EXPECT FAIRLY WIDESPREAD CONVECTION OVER THE MOUNTAINS FROM
THE SANGRES WESTWARD AS DEEP MOIST AIR MASS WILL BE OVER THE
AREA...WHILE EASTERN MOUNTAIN SLOPES/I25 CORRIDOR/SOUTHEAST PLAINS
SEE MUCH LESS ACTIVITY UNDER RATHER UNFAVORABLE W-SW WINDS AT THE
SURFACE AND ALOFT. GIVEN RATHER HEALTHY PRECIPITABLE WATER
VALUES...STORMS OVER THE HIGHER TERRAIN WILL HAVE THE POTENTIAL FOR
FAIRLY HEAVY RAINFALL RATES...THOUGH RELATIVELY STRONG STEERING
CURRENTS SHOULD KEEP ACTIVITY MOVING AND REDUCE THE FLOOD HAZARD
SOMEWHAT. MAX TEMPS OVER THE MOUNTAINS AND VALLEYS SHOULD COOL A FEW
DEGF FROM WED MAXES...WHILE I-25 CORRIDOR AND EASTERN PLAINS SEE
LITTLE CHANGE WITH RATHER HOT TEMPS PERSISTING.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 307 PM MDT WED SEP 2 2015
THURSDAY NIGHT THROUGH SATURDAY...FAIRLY GOOD MODEL AGREEMENT
BETWEEN THE GFS AND EC INTO THE WEEKEND...AS COLORADO REMAINS IN THE
MIDDLE OF A RIDGE OF HIGH PRESSURE TO THE EAST.,..AND A
STRENGTHENING LOW PRESSURE SYSTEM OVER THE PAC NW. THIS WILL PRODUCE
BRISK SW FLOW ALOFT ACROSS THE 4 CORNERS AND COLORADO...DRAWING A
HEALTHY AMOUNT OF MONSOON MOISTURE INTO THE FORECAST AREA. THIS WILL
ALSO ENCOURAGE DIURNAL CONVECTION EACH AFTN AND EVENING...WITH
ISOLATED TO SCATTERED POPS OVER THE MTS AND ISOLATED ELSEWHERE. LOOK
FOR MILD NIGHTS...AND MAX TEMPS EACH AFTN IN THE 70S TO NEAR 80 FOR
THE HIGH VALLEYS...AND AROUND 90 F FOR THE E PLAINS.
SUNDAY AND MONDAY...MODELS START TO DISAGREE BEGINNING ON SUN. THE
UPPER LOW OVER THE PAC NW WILL ROTATE ACROSS THE NORTHERN ROCKIES ON
SAT...MT ON SUN AND BACK NORTH INTO CANADA FOR MON. THE FLOW ALOFT
WILL TRANSITION TO A MORE WESTERLY DIRECTION...TEMPORARILY CUTTING
OFF THE MONSOON TAP FROM THE SW. MODELS SOMEWHAT AGREE ON THIS...BUT
THE GFS STARTS TO SNEAK MOISTURE BACK UP INTO THE STATE MON AFTN AND
EVE. FEEL THIS IS REASONABLE SINCE THERE WILL STILL BE PLENTY OF
DAYTIME HEATING...SO KEPT ISOLATED POPS OVER THE MTS...MAINLY ALONG
THE CONTDVD...MON AFTN AND EVE.
TUESDAY AND WEDNESDAY...THE EC LEANS TOWARDS KEEPING THE ENTIRE AREA
DRY THROUGH WED...WHILE THE GFS HAS MORE OF A SW FLOW ALOFT WHICH
ATTEMPTS TO DRAW SOME OF THE MONSOON MOISTURE BACK INTO THE STATE.
DECIDED TO SIDE WITH THE GFS...BUT KEPT POPS LIGHT THROUGH WED WHILE
COOLING MAX TEMPS BOTH DAYS BY ABOUT 5 DEGREES. MOORE
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 307 PM MDT WED SEP 2 2015
TSRA WILL REMAIN CONFINED MAINLY TO THE MOUNTAINS/INTERIOR VALLEYS
INTO THIS EVENING...AND WILL CARRY A VCTS MENTION ONLY AT KALS FOR
LATE AFTERNOON INTO THE EVENING. COULD SEE SOME VERY WEAK CONVECTION
DRIFT OFF THE MOUNTAINS TOWARD KCOS AND KPUB 23Z-03Z...BUT DOUBTFUL
THEY WILL LAST LONG ENOUGH TO REACH EITHER TERMINAL AND WON`T
INCLUDE A MENTION IN THE TAFS AT THIS POINT. OVERNIGHT...SOME WEAK
CONVECTION WILL LINGER ALONG THE CONTINENTAL DIVIDE INTO THU
MORNING...WITH POSSIBLY SOME MVFR CIGS/VIS OVER THE HIGHER PEAKS AND
PASSES. ON THU...CONVECTION WILL BECOME FAIRLY WIDESPREAD BY
AFTERNOON OVER THE MOUNTAINS...ESPECIALLY ALONG THE CONTINENTAL
DIVIDE WHERE AREAS OF IFR CONDITIONS WILL BE LIKELY THROUGH THE DAY.
FOR THE TAF SITES...BEST CHANCE OF TSRA THU WILL BE AT KALS...LESSER
CHANCES AT KPUB AND KCOS.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...PETERSEN
LONG TERM...MOORE
AVIATION...PETERSEN
AREA FORECAST DISCUSSION
NWS MIAMI FL
353 PM EDT WED SEP 2 2015
.DISCUSSION...
ISOLATED TO SCATTERED THUNDERSTORMS CONTINUE ACROSS MAINLY THE
EAST COAST METRO AREAS WITH A RATHER WEAK EAST COAST SEA BREEZE.
OVER THE NEXT FEW HOURS...ADDITIONAL CONVECTION IS EXPECTED TO
DEVELOP MAINLY WEST OF THE EAST COAST METRO AREAS DUE TO
SUBSEQUENT OUTFLOW BOUNDARY INTERACTIONS. LATEST HRRR AGREES BY
PUSHING MOST OF THE LATER CONVECTION ACROSS THE NORTHWEST INTERIOR
THROUGH THE LATE AFTERNOON AND EARLY EVENING HOURS. MAIN THREATS
WITH THESE STORMS WILL BE FREQUENT LIGHTNING AND BRIEF HEAVY
DOWNPOURS.
UPPER RIDGING IS STILL EXPECTED TO BE THE MAIN WEATHER FEATURE
ACROSS SOUTH FLORIDA THROUGH THE REMAINDER OF THE WEEK AND INTO
THE FIRST PART OF THE WEEKEND. THIS WILL KEEP SURFACE WINDS AND
STEERING FLOW GENERALLY LIGHT WITH AFTERNOON AND EARLY EVENING
CONVECTION REMAINING MAINLY ACROSS THE INTERIOR.
BY LATE IN THE WEEKEND THROUGH THE EARLY PART OF NEXT WEEK...UPPER
RIDGING IS EXPECTED TO BREAK DOWN AS A BROAD H5 TROUGH DIGS
SOUTHWARD THROUGH THE FLORIDA PENINSULA AND INTO THE EASTERN GULF
OF MEXICO. THIS WILL USHER IN A MORE SOUTHWESTERLY MID LEVEL FLOW.
MODELS ALSO HINT AT SLIGHTLY DRIER AIR PUSHING INTO THE AREA
DURING THIS TIME FRAME WHICH WILL DO LITTLE MORE THAN DECREASE
POPS SLIGHTLY FOR THE EARLY TO MID WEEK TIME FRAME NEXT WEEK.
&&
.AVIATION...
CONVECTION IS EXPECTED TO STAY AWAY FROM THE EAST COAST SITES
THROUGH THE REMAINDER OF THE AFTERNOON. LATEST HRRR KEEPS
ADDITIONAL OUTFLOW BOUNDARY DRIVEN CONVECTION ACROSS THE INTERIOR
INTO THE EARLY EVENING HOURS...SOME POSSIBLY AFFECTING KAPF.
OTHERWISE...LIGHT SOUTH TO SOUTHEASTERLY FLOW TO PREVAIL.
&&
.MARINE...
RATHER TRANQUIL MARINE CONDITIONS ARE EXPECTED THROUGH THE NEXT
COUPLE OF DAYS WITH LIGHT EAST TO SOUTHEAST WIND OF LESS THAN 10 KNOTS
AND SEAS OF 2 FEET OR LESS ACROSS ALL WATERS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 77 92 77 92 / 20 30 30 50
FORT LAUDERDALE 79 91 78 92 / 20 30 30 60
MIAMI 78 92 78 93 / 20 30 30 60
NAPLES 78 90 78 90 / 20 30 10 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...10/CD
LONG TERM....10/CD
AVIATION...10/CD
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
910 AM EDT WED SEP 2 2015
.UPDATE...
THE REMNANTS OF ERIKA NOW MOVING INLAND OVER THE NORTHEAST GULF
EARLY THIS MORNING WILL CONTINUE TO MOVE SLOWLY NORTHEAST INTO
SOUTHEAST GEORGIA THROUGH THE AFTERNOON WITH THE TRAILING TROUGH
AXIS EXTENDING SOUTHWEST INTO THE GULF GRADUALLY WASHING OUT AS
HIGH PRESSURE SURFACE AND ALOFT RE-BUILDS IN OVER THE REGION. 88D
RETURNS NOW SHOW SOME SHOWERS ASSOCIATED WITH THE TROUGH MOVING
ONSHORE ACROSS LEVY COUNTY WHICH WILL CONTINUE THROUGH THE MORNING
WITH OTHER SHOWERS AND A FEW STORMS NOTED OVER THE COASTAL WATERS
WEST OF SARASOTA...CHARLOTTE...AND LEE COUNTIES...OTHERWISE MAINLY
CLEAR SKIES WERE BEING OBSERVED ACROSS THE FORECAST AREA.
MORNING RAOB DATA SHOWS A MOIST AND UNSTABLE AIRMASS OVER THE
REGION WITH PW`S IN THE 1.9 TO 2.2 INCH RANGE. THIS MOISTURE
COMBINED WITH DAYTIME HEATING SHOULD ALLOW FOR SOME SHOWERS AND
STORMS TO DEVELOP ALONG THE INLAND MOVING SEA BREEZE DURING LATE
MORNING AND INTO THE AFTERNOON. HOWEVER WITH DRY MID LEVEL AIR AND
MILD MID LEVEL TEMPS (-5 TO -6C) IN PLACE OVER THE REGION
ASSOCIATED WITH THE RIDGING ALOFT CONVECTIVE DEVELOPMENT SHOULD
AGAIN BE DELAYED SOME...WITH OVERALL STORM COVERAGE LIKELY TO BE
LIMITED AS WELL WITH ONLY ISOLATED TO LOW SCATTERED RANGE POPS
EXPECTED...WITH HIGHEST POPS OVER INLAND LOCATIONS ALONG THE SEA
BREEZE MERGER...AND TO THE NORTH OF THE I 4 CORRIDOR WHERE DEEPER
MOISTURE RESIDES. THE HRRR AS WELL AS OTHER HI-RES MODELS ARE IN
AGREEMENT WITH THIS SO PLAN TO CUT BACK POPS SLIGHTLY IN A MID
MORNING UPDATE...OTHERWISE NO OTHER GRID OR ZONE CHANGES EXPECTED
AT THIS TIME.
&&
.AVIATION...
OVERALL CONVECTIVE COVERAGE SHOULD BE LIMITED TODAY DUE TO
MILD DRY AIR ALOFT OVER THE REGION...BUT HAVE INCLUDED VCTS AT
ALL SITES JUST THE SAME AFTER 15Z TO ACCOUNT FOR ANY SHRA/TSRA
THAT MAY IMPACT THE TERMINAL SITES...OTHERWISE MAINLY VFR IS
EXPECTED DURING THE NEXT 24 HOURS. LIGHT AND VARIABLE WINDS THIS
MORNING WILL BECOME SOUTHWEST TO WEST AROUND 10 KNOTS AFTER 16Z.
LIGHT AND VARIABLE WINDS WILL RETURN TO ALL SITES AFTER 01Z
TONIGHT.
&&
.MARINE...
THE REMNANTS OF ERIKA OVER THE NORTHEAST GULF EARLY THIS MORNING
WILL CONTINUE TO MOVE TO THE NORTHEAST INTO SOUTHEAST GEORGIA THE
REMAINDER OF TODAY WITH THE TRAILING TROUGH AXIS OVER THE GULF
GRADUALLY WASHING OUT AS HIGH PRESSURE RE-BUILDS IN OVER THE
WATERS. A WEAK PRESSURE PATTERN UNDER THE HIGH WILL SUPPORT
TRANQUIL BOATING CONDITIONS WITH LIGHT WINDS AND SLIGHTS SEAS
WITH AN ONSHORE SEA BREEZE COMPONENT DEVELOPING ALONG THE COAST
BY LATE MORNING. ONGOING FORECAST IS IN GREAT SHAPE WITH NO
CHANGES EXPECTED IN THE NEXT FORECAST ISSUANCE LATER THIS MORNING.
&&
.HYDROLOGY...
HIGH RAINFALL ACCUMULATIONS THIS SUMMER...AND PARTICULARLY DURING
THE LAST 5 TO 6 WEEKS OR SO...HAVE BROUGHT NUMEROUS RIVERS ACROSS
THE AREA INTO MINOR OR MODERATE FLOOD. THERE ARE CURRENTLY SIX
RIVER FORECAST POINTS IN FLOOD ACROSS THE FORECAST AREA...AND TWO
OTHERS ARE IN ACTION STAGE.
RESIDENTS LIVING ALONG RIVERS OR FASTER FLOWING STREAMS SHOULD
CONTINUE TO MONITOR WATER LEVELS AND BE READY TO MOVE TO HIGHER
GROUND SHOULD FLOODING BE OBSERVED...ESPECIALLY WITH THE
POTENTIAL FOR SOME LOCALLY HEAVY RAINFALL THROUGH THE REMAINDER
OF THE WEEK.
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE/AVIATION/MARINE/HYDROLOGY...57/MCMICHAEL
UPPER AIR...74/WYNN
DECISION SUPPORT...05/CARLISLE
AREA FORECAST DISCUSSION
NWS MIAMI FL
200 AM EDT WED SEP 2 2015
.AVIATION...
WEAK HIGH PRESSURE WILL RESULT IN A TYPICAL SUMMER DAY ACROSS
SOUTH FLORIDA WITH L/V EARLY MORNING WIND AND SEA BREEZES
DEVELOPING ALONG BOTH COASTS. STEERING FLOW WILL BE SOUTHEAST TO
NORTHWEST SO AS DIURNAL CONVECTION DEVELOPS ALONG THE SEA BREEZE
BOUNDARIES, THE CELLS WILL MOVE INLAND AND AWAY FROM THE
TERMINALS. THIS ACTIVITY SHOULD BE FAR ENOUGH AWAY TO NOT INCLUDE
IN THE FORECAST AT THIS TIME.
KOB
&&
.PREV DISCUSSION... /ISSUED 800 PM EDT TUE SEP 1 2015/
UPDATE...
SHOWERS AND THUNDERSTORMS CONTINUE TO DECREASE IN COVERAGE ACROSS
THE AREA EARLY THIS EVENING WITH HEATING LOSS. LATEST HRRR KEEPS
ONLY ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ACROSS MAINLY
THE ATLANTIC AND GULF WATERS THROUGH THE OVERNIGHT HOURS. UPDATED
FORECAST TO ADJUST FOR THESE TRENDS.
PREV DISCUSSION... /ISSUED 743 PM EDT TUE SEP 1 2015/
AVIATION...
VFR OVERNIGHT. OUTFLOW BOUNDARY WHICH MOVED DUE EAST LATE THIS
AFTERNOON GENERATED A FEW WIND GUSTS AND SOME BRIEF MVFR CIGS
WHICH WILL DISSIPATE THIS EVENING. REGIME IS SIMILAR TOMORROW,
WITH SEABREEZES ON BOTH COASTS AND STORMS FOCUSED OVER THE
INTERIOR. EAST COAST TERMINALS, POSSIBLY WITH THE EXCEPTION OF TMB
AND PBI, MAY STAY DRY AGAIN. WITH THE GULF BREEZE FADING, STORMS
JUST EAST OF APF MAY CROSS THAT TERMINAL IN THE NEAR TERM TONIGHT.
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
228 AM EDT WED SEP 2 2015
.SYNOPSIS...
AN UPPER LEVEL RIDGE CENTERED TO OUR SOUTH WILL SHIFT SLOWLY WEST
TOWARDS FLORIDA AND THE EASTERN GULF OF MEXICO...WHILE AN UPPER
LEVEL TROUGH DEVELOPS OVER THE EAST COAST...THROUGH FRIDAY. A
RELATIVELY DRY ATMOSPHERE WILL REMAIN IN PLACE OVER OUR FORECAST
AREA TODAY...ENSURING FAIR WEATHER WITH A TREND TOWARDS WARMER MAX
TEMPS. A SLIGHT INCREASE IN MOISTURE AND SOME UPPER ENERGY
EXPECTED TO LEAD TO A SLIGHT CHANCE OF MAINLY AFTERNOON AND
EVENING SHOWERS AND THUNDERSTORMS THURSDAY AND FRIDAY. INDICATIONS
OF A BACK DOOR FRONT AND INCREASING MOISTURE MAY SPELL INCREASING
CHANCES FOR PRECIPITATION THIS WEEKEND INTO EARLY NEXT
WEEK...ALONG WITH A TREND TOWARDS COOLER TEMPS.
&&
.NEAR TERM /THROUGH TONIGHT/...
A WEAK SURFACE PRESSURE PATTERN WILL REMAIN OVER OUR FORECAST
AREA (FA) WITH A RELATIVELY DRY ATMOSPHERE...ENSURING FAIR
WEATHER. FORECAST SOUNDINGS CONTINUE TO INDICATE A DRY AND CAPPED
ATMOSPHERE...ALTHOUGH A FEW SHALLOW DIURNAL SHOWERS POSSIBLE.
GUIDANCE TRENDING A LITTLE HIGHER ON MAX TEMPS. PATCHY FOG
POSSIBLE THROUGH EARLY THIS MORNING. UPPER ENERGY AND REMNANT
CIRCULATION OF FORMER TS ERIKA...AND ASSOCIATED
MOISTURE...ROTATING AROUND THE UPPER HIGH STILL APPEARS WILL BE
SHUNTED TO THE EAST AND REMAIN SOUTH OF OUR FORECAST AREA AS
MIDWEST UPPER TROUGH SHIFTS SE TOWARDS THE MID ATLANTIC.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
UPPER RIDGE WILL SHIFT WEST OVER FLORIDA AND THE EASTERN
GULF...WHILE UPPER TROUGH REMAINS OVER THE EAST COAST...WITH A
SERIES OF DISTURBANCES MOVING THROUGH. MODELS INDICATE A SLIGHT
INCREASE IN MOISTURE...WHICH ALONG WITH SOME UPPER LIFT AND
DIURNAL HEATING...APPEARS TO PROVIDE A SLIGHT CHANCE OF MAINLY
DIURNAL SHOWERS AND THUNDERSTORMS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
THOUGH DIFFERENCES REMAIN BETWEEN GFS AND ECMWF ON SPECIFICS AND
TIMING...MODELS CONTINUE TO GENERALLY INDICATE BACK DOOR FRONT
MOVING INTO OR THROUGH THE REGION...WITH CLOSED LOW ALOFT AND A
LOW LEVEL EASTERLY FLOW OFF THE ATLANTIC LEADING TO INCREASING
ATMOSPHERIC MOISTURE AND POPS...AND TREND TOWARDS LOWER TEMPS.
WILL MAINTAIN BLEND OF GUIDANCE.
&&
.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
WEAK HIGH PRESSURE AT THE SURFACE AND A BUILDING UPPER RIDGE
ALOFT...ALONG WITH A GENERALLY DRY AIR MASS SHOULD LEAD TO AN
UNEVENTFUL WEATHER DAY. HOWEVER...STRONG RADIATIONAL COOLING EARLY
THIS MORNING HAS ALREADY RESULTED IN MVFR VSBYS AT AGS AND EXPECT
MVFR/IFR VSBYS AT AGS AND EVENTUALLY LATER AT OGB. HRRR CEILING
FORECAST INDICATES SOME POSSIBLE LIFR CIGS MOVING INTO OGB AROUND
10-11Z BUT NO OTHER GUIDANCE SHOWING THIS AND WILL LEAVE OUT OF
THE FORECAST AT THIS TIME. LIGHT TO CALM WINDS THROUGH MID MORNING
THEN LIGHT AND VARIABLE WINDS EXPECTED WITH A PREVAILING SOUTHERLY
COMPONENT TO THE WINDS. PWAT VALUES AROUND 1.5 INCHES AND LACK OF
UPPER FORCING SUGGESTS CONVECTION PROBABILITIES ARE LOW AND WILL
NOT BE INCLUDED IN THE FORECAST.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE IN MAINLY EARLY
MORNING WITH FOG. BY LATE IN THE EXTENDED PERIOD...AFTERNOON AND
EVENING SCATTERED SHOWERS OR THUNDERSTORMS WILL BE POSSIBLE.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
149 AM EDT WED SEP 2 2015
.SYNOPSIS...
AN UPPER-LEVEL RIDGE WILL GRADUALLY SHIFT EAST TOWARDS FLORIDA...
WHILE AN UPPER TROUGH WILL SHIFT SE FROM THE OHIO VALLEY TO
OFFSHORE THE MID ATLANTIC COAST. THIS WILL ENSURE THAT A
RELATIVELY DRY ATMOSPHERE WILL REMAIN IN PLACE OVER OUR REGION
THROUGH LATE WEEK...WITH SOME INCREASE IN MAX TEMPS. INDICATIONS
OF A BACK DOOR FRONT AND INCREASING MOISTURE MAY SPELL INCREASING
CHANCES FOR PRECIPITATION BY THIS WEEKEND...ALONG WITH SLIGHTLY
COOLER TEMPS.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
A WEAK SURFACE PRESSURE PATTERN WITH RIDGING ALOFT WILL DOMINATE
THROUGH TONIGHT. DEEP MOISTURE WILL REMAIN SOUTHEAST OF THE AREA.
SATELLITE TRENDS SUPPORT HIGH CLOUDINESS MAINLY IN THE SOUTHEAST
SECTION OF THE FORECAST AREA TONIGHT. PATCHY FOG SHOULD OCCUR
DURING THE EARLY MORNING HOURS MAINLY IN THE RIVER VALLEYS. THE
TEMPERATURE GUIDANCE WAS CONSISTENT.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/...
UPPER RIDGE WILL SHIFT WEST OVER FLORIDA AND THE EASTERN
GULF...WHILE MIDWEST CLOSED LOW OPENS AND SHIFTS SE TOWARDS THE
MID ATLANTIC COAST. UPPER ENERGY...CURRENTLY ALONG THE WEST COAST
OF FLORIDA MOVING NORTHEAST...AND MOISTURE TO OUR SOUTH APPEARS
WILL GET SUPPRESSED AND EJECTED TO THE EAST/SE...ALONG COASTAL
GEORGIA AND SOUTH CAROLINA...REMAINING SOUTHEAST OF OUR FA.
RELATIVELY DRY AIR APPEARS WILL REMAIN IN PLACE OVER OUR
FA...THOUGH SOME SLIGHT INCREASE IN MOISTURE NOTED. SLIGHT CHANCE
MAINLY DIURNAL POPS APPEARS OK. TEMPERATURES WARMING THE NEXT
COUPLE OF DAYS INTO THE MID 90S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
12Z GFS SIMILAR WITH 00Z ECMWF WITH SHIFTING UPPER LEVEL LOW FROM
THE WESTERN GULF OF MEXICO EAST INTO THE SOUTHEASTERN
STATES/CAROLINAS OVER THE WEEKEND INTO EARLY NEXT WEEK. EXPECT AN
INCREASE IN MOISTURE DURING THE PERIOD. ENSEMBLE POP GUIDANCE
SUPPORTS CHANCE POPS AT LEAST THROUGH THE WEEKEND. GFS DEVELOPING
WEAK LOW PRESSURE ALONG CAROLINA/GEORGIA COAST BY MONDAY BUT ECMWF
WEAKER AND MOISTURE MAINLY SOUTH OF THE AREA WITH SURFACE RIDGE
BUILDING SOUTH FROM MID ATLANTIC STATES. TEMPERATURES NEAR
CLIMATOLOGY NORMALS.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
WEAK HIGH PRESSURE AT THE SURFACE AND A BUILDING UPPER RIDGE
ALOFT...ALONG WITH A GENERALLY DRY AIR MASS SHOULD LEAD TO AN
UNEVENTFUL WEATHER DAY. HOWEVER...STRONG RADIATIONAL COOLING EARLY
THIS MORNING HAS ALREADY RESULTED IN MVFR VSBYS AT AGS AND EXPECT
MVFR/IFR VSBYS AT AGS AND EVENTUALLY LATER AT OGB. HRRR CEILING
FORECAST INDICATES SOME POSSIBLE LIFR CIGS MOVING INTO OGB AROUND
10-11Z BUT NO OTHER GUIDANCE SHOWING THIS AND WILL LEAVE OUT OF
THE FORECAST AT THIS TIME. LIGHT TO CALM WINDS THROUGH MID MORNING
THEN LIGHT AND VARIABLE WINDS EXPECTED WITH A PREVAILING SOUTHERLY
COMPONENT TO THE WINDS. PWAT VALUES AROUND 1.5 INCHES AND LACK OF
UPPER FORCING SUGGESTS CONVECTION PROBABILITIES ARE LOW AND WILL
NOT BE INCLUDED IN THE FORECAST.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE IN MAINLY EARLY
MORNING WITH FOG. BY LATE IN THE EXTENDED PERIOD...AFTERNOON AND
EVENING SCATTERED SHOWERS OR THUNDERSTORMS WILL BE POSSIBLE.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS POCATELLO ID
233 PM MDT WED SEP 2 2015
.DISCUSSION...STRONG LOW PRESSURE DISTURBANCE CONTINUES TO MOVE
SOUTH ALONG THE COAST TOWARDS SOUTHERN OREGON AND NORTHERN
CALIFORNIA. SOME SOUTHERLY FLOW INTO SOUTHEAST IDAHO THIS
AFTERNOON WITH POTENTIAL FOR SUBTROPICAL MOISTURE SLIPPING INTO
THE SOUTH CENTRAL AND CARIBOU HIGHLANDS THIS EVENING AND
OVERNIGHT. LATEST SATELLITE AND RADAR IMAGERY SUGGEST THIS HAS
BEEN DELAYED A BIT AND THE 18Z NAM12 AND RAP MODEL ALSO FAVOR
TIMING CLOSER TO MIDNIGHT AND EARLY MORNING. THE REMAINDER OF
SOUTHEAST IDAHO REMAINS DRY TONIGHT. THURSDAY AND THURSDAY NIGHT
STILL LOOKING FOR THE EASTERN EDGE OF THE LOW TO BRUSH CUSTER
COUNTY WITH A FEW SHOWERS AS IT MOVES SOUTH. THERE WILL BE A FEW
TRICKLES OF MOISTURE SLIPPING INTO THE EASTERN HIGHLANDS FROM THE
SOUTH AS WELL. SOUTHERLY WINDS FRIDAY WILL BE BREEZY IN THE SOUTH
CENTRAL HIGHLANDS AND SNAKE PLAIN.
MODEL CONSENSUS HAS THE LOW MOVING EAST INTO IDAHO FRIDAY NIGHT
AND SATURDAY FOR SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OVER
THE FORECAST AREA. BY SUNDAY THE PATTERN QUICKLY REVERTS BACK TO A
MILD WEST TO NORTHWEST FLOW THAT IS LARGE DRY EXCEPT FOR MAY NEAR
MONIDA PASS ON THE MONTANA BORDER. THERE ARE SOME MODEL
DIFFERENCES WITH A MINOR DISTURBANCE THAT CROSSES NORTH IDAHO AND
MONTANA ON MONDAY AND NIPPING THIS AREA WITH SPOTTY SHOWERS...THEN
IT IS BACK TO A DRY PATTERN THE LATER PART OF THE WEEK. RS
&&
.AVIATION...MODELS PROJECT A DISTURBANCE TO MOVE NORTH OUT OF UTAH
THIS EVENING AND PRODUCE SHOWERS FOR KPIH AND KIDA. AN ISOLATED
LIGHTNING STRIKE CANNOT BE RULED OUT...BUT NOT ENOUGH CONFIDENCE TO
INCLUDE IN TAFS. THE DISTURBANCE WILL CONTINUE NORTHWARD AND WILL
LIKELY EXIT INTO MT/WY BEFORE SUNRISE. HINSBERGER
&&
.FIRE WEATHER...RED FLAG CONDITIONS CONTINUE THROUGH 9 PM THIS
EVENING DUE TO GUSTY WINDS AND LOW HUMIDITY. A STRONG SOUTHWESTERLY
BOUNDARY LAYER FLOW AHEAD OF A COLD FRONT WILL IMPACT THE CENTRAL
IDAHO MOUNTAINS. THIS FLOW PARTICULARLY FAVORS DRY/WARM DOWNSLOPE
WINDS IN THE VALLEYS UNTIL JUST AFTER SUNSET TONIGHT. THE COLD FRONT
WILL STALL OVER THE CENTRAL MOUNTAINS OVERNIGHT AND PASS THROUGH
THURSDAY NIGHT. HUMIDITY IS GENERALLY EXPECTED TO RECOVER AND WINDS
SHOULD NOT BE AS STRONG ON THURSDAY. MOISTURE INCREASES SATURDAY AS
SOUTHERLY FLOW IS ENHANCED AHEAD OF A DEEP UPPER LOW...WHICH MAY
BRING WETTING RAINS TO THE CENTRAL MOUNTAINS. THE LOW WILL ALSO
BRING THE THREAT OF THUNDERSTORMS AS THE AIRMASS BECOMES MORE
UNSTABLE. HINSBERGER
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR IDZ410-475-476.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
645 PM CDT THU SEP 3 2015
.UPDATE...
645 PM CDT
THE FRONTAL BOUNDARY IS SLOWLY SAGGING SOUTHWARD NEAR THE WI
STATE LINE...WHILE LAKE-MODIFIED FRONT HAS SURGED AHEAD AND IS
ABOUT TO PASS SOUTHWARD THROUGH DOWNTOWN CHICAGO AS OF 640 PM.
TEMPORARY WIND GUSTS OF 20 TO 25 MPH ARE EXPECTED BEHIND THIS WITH
A 10-15 DEGREE DROP IN 10-15 MINUTES PER UPSTREAM OBSERVATIONS.
NEARLY UNCAPPED AIR AT 2000-3000 J/KG OF MLCAPE PER AMDAR DATA
AND MODIFIED RAP SOUNDINGS HAS RESULTED IN ISOLATED STORMS ALONG
THE FRONT AND A FEW SHOWERS ON THE LAKE BREEZE CONVERGENCE. WITH
THE BOUNDARIES AND SOME OF THEIR ORIENTATIONS IN RESPECT TO THE
MEAN WIND FIELD...THERE IS A POOL OF LOW-LEVEL VORTICITY AVAILABLE
FOR ANY STORM/SHOWER UPDRAFTS LATCHED TO THE BOUNDARY. SO WHILE
THERE IS NOT MUCH AT ALL FOR WIND SHEAR THROUGH THE STORM
DEPTH...CANNOT RULE OUT A FEW STORMS HAVING BRIEF ROTATION AND
HAVE ALREADY SEEN THAT IN DOPPLER VELOCITY DATA WITH A COUPLE
STORMS ON THE BOUNDARIES. THE KEY IS WHILE THE ENVIRONMENT IS
FAVORABLE FOR BRIEF LOW-LEVEL ROTATION...IT IS NOT FAVORABLE FOR
ANYTHING SUSTAINED. ALSO...WITH PEAK HEATING NOW HAVE PASSED...A
GENERAL WEAKENING IN INTENSITY IS EXPECTED AS LOW-LEVEL LAPSE
RATES EASE...SO THIS BEHAVIOR SHOULD ONLY LAST ANOTHER HOUR OR TWO
AT MOST.
THE SLOW MOVEMENT OF STORMS PER LITTLE LIGHT MID AND UPPER FLOW
COULD BRING A QUICK ONE INCH TO ANY AREAS DIRECTLY UNDER THE
STORMS.
MINOR ADJUSTMENTS MADE TO FORECAST HOURLY POPS AND HOURLY
TEMPERATURE TRENDS FOR THE SHARP COOL DOWN.
MTF
&&
.SHORT TERM...
254 PM CDT
THROUGH SATURDAY...
MAIN FORECAST CONCERNS OVER THE NEXT COUPLE DAYS WILL BE CONTINUED
UNSEASONABLY WARM AND HUMID CONDITIONS...AS WELL AS PRECIPITATION
CHANCES.
THIS AFTERNOON...SATELLITE IMAGERY AND SURFACE OBS SHOW A WEAK
TROUGH DRAPED FROM NEAR LSE THROUGH MSN AND MKE AND ACROSS LAKE
MICHIGAN. THIS TROUGH WILL CONTINUE TO SAG SOUTH THE THE REMAINDER
OF THE AFTERNOON AND INTO THE EVENING WITH WINDS TURNING FROM WEST-
SOUTHWEST AHEAD TO NORTHEAST BEHIND. THIS BOUNDARY IS EXPECTED TO
ENHANCE/BECOME COUPLED WITH A LAKE BREEZE THIS AFTERNOON WHICH
SHOULD HELP PUSH TEMPERATURES BACK INTO THE 70S ALONG THE LAKE
FRONT. THE BOUNDARY COULD ALSO SERVE AS THE FOCUS FOR
ISOLATED/WIDELY SCATTERED THUNDERSTORM DEVELOPMENT. LATEST SPC MESO-
ANALYSIS PAGE SHOWS AXIS OF MODERATELY STRONG INSTABILITY ACROSS
NORTHERN ILLINOIS...WEAKLY CAPPED OR UNCAPPED...HOWEVER LACK OF ANY
FORCING AND WEAK MIDLEVEL HEIGHT RISES APPEAR TO BE KEEPING
CONVECTION IN CHECK FOR THE MOMENT. AS THE AFOREMENTIONED TROUGH
MOVES INTO THE AREA THIS EVENING...IT SHOULD BE SUFFICIENT TO KICK
OF A FEW THUNDERSTORMS THOUGH CHANCES WILL THEN BEGIN TO DIMINISH
LATE THIS EVENING AS THE BOUNDARY LAYER BEGINS TO STABILIZE
NOCTURNALLY. WITH THE BOUNDARY IN PLACE...ISOLATED DEVELOPMENT MAY
LINGER OVERNIGHT...BUT NOT EXPECTING MUCH COVERAGE.
FOR FRIDAY...
TROUGH AXIS SETTLES OVER THE AREA ON FRIDAY WITH FAIRLY WEAK FLOW AT
THE SURFACE. LOW PRESSURE OVER THE PLAINS WILL ADVANCE EASTWARD WITH
MODEST WAA SPREADING INTO PORTIONS OF NORTHERN ILLINOIS. ALSO...A
LAKE BREEZE FORMS IN THE AFTERNOON. ANOTHER WARM AND HUMID DAY IS
ON TAP...THUS AN UNSTABLE ENVIRONMENT WILL DEVELOP AGAIN. GUIDANCE
IS MIXED WITH CONVECTIVE DEVELOPMENT...BUT HAVE LEANED AWAY FROM
THE MORE AGRESSIVE GUIDANCE AT THIS POINT...AND HAVE KEPT THE
HIGHEST POPS...STILL IN THE CHANCE CATEGORY...FOR THE LATER
AFTERNOON ALONG THE LAKE BREEZE.
BMD
&&
.LONG TERM...
SATURDAY THROUGH THURSDAY...
308 PM...MULTIPLE FORECAST CONCERNS INCLUDING HIGH TEMPS SUNDAY
AND MONDAY...PRECIP CHANCES/TIMING SUNDAY NIGHT THRU WEDNESDAY
THEN COOLER/LESS HUMID END OF NEXT WEEK.
THE UPPER RIDGE WILL BE BUILDING ACROSS THE AREA ON SATURDAY AND
MODELS ARE IN GENERAL AGREEMENT WITH DECREASING POPS THRU THE DAY
AND LIKELY DRY CONDITIONS INTO SATURDAY EVENING. WINDS WILL LIKELY
BE LIGHT ENOUGH THAT A LAKE BREEZE TURNING WINDS SOUTHEASTERLY
ALONG THE IL SHORE SHOULD DEVELOP. NOT SURE IF THIS WILL BE STRONG
ENOUGH TO AID ANY ISOLATED CONVECTION TO DEVELOP. POSSIBLE THAT
THERE COULD STILL BE SOME ISOLATED SHOWERS OR THUNDERSTORMS
SATURDAY AFTERNOON SO MAINTAINED SLIGHT CHANCE POPS WITH DRY
CONDITIONS EXPECTED SATURDAY NIGHT AND SUNDAY.
HIGH TEMPS IN THE UPPER 80S/AROUND 90 LOOK REASONABLE SATURDAY...
COOLER ALONG THE IL SHORE. SUNDAY LOOKS TO BE WARMER WITH HIGHS
GENERALLY IN THE LOWER 90S MOST LOCATIONS. PERHAPS SLIGHTLY
COOLER ALONG THE IL SHORE WITH SOUTH/SOUTHEAST WINDS. WINDS MAY BE
A BIT STRONGER ON SUNDAY...PERHAPS IN THE 10-20 MPH RANGE
ESPECIALLY ACROSS NORTHWEST IL BUT WITH DEWPOINTS IN THE UPPER
60S/LOWER 70S BOTH DAYS...AFTERNOON HEAT INDICES IN THE MID 90S
POSSIBLE BOTH DAYS.
A FRONTAL BOUNDARY WILL MOVE SOUTHEAST ACROSS THE MIDWEST SUNDAY
INTO SUNDAY NIGHT AND 12Z GFS/ECMWF ARE IN GOOD AGREEMENT WITH
PRECIP HOLDING OFF UNTIL AFTER MIDNIGHT...PERHAPS NOT UNTIL CLOSER
TO DAWN MONDAY MORNING SO SUNDAY EVENING LOOKS DRY. AS THIS FRONT
SAGS INTO THE CWA MONDAY...FORCING BEGINS TO WEAKEN SO CONFIDENCE
REGARDING PRECIP COVERAGE AND TIMING IS FAIRLY LOW. COULD BE
DECAYING SHOWERS/CONVECTION IN THE MORNING AND THEN NEW
ADDITIONAL DEVELOPMENT WITH DAYTIME HEATING LATER MONDAY
AFTERNOON/EVENING. AT THIS POINT...MAINTAINED CHANCE POPS BOTH
LATE SUNDAY NIGHT AND ON MONDAY. HIGH TEMPS WILL BE TRICKY FOR
MONDAY. COOLER ACROSS NORTHERN AREAS SEEMS ON TRACK BUT SOUTHEAST
AREAS COULD EASILY GET BACK INTO THE UPPER 80S/LOWER 90S.
THIS FRONT THEN LAYS OUT ACROSS THE AREA AS IT WEAKENS MONDAY NIGHT
INTO TUESDAY WHILE A STRONGER COLD FRONT PUSHES ACROSS THE NORTHERN
PLAINS TUESDAY AND REACHES THE AREA TUESDAY NIGHT INTO WEDNESDAY.
WHILE THIS IS STILL SEVERAL DAYS OUT...GIVEN THE HIGH DEWPOINT AIR
LIKELY POOLING ALONG THIS BOUNDARY...ITS POSSIBLE THERE COULD BE
PERIODS OF HEAVY RAIN AT LEAST ACROSS SOME PARTS OF THE REGION.
ONCE THE SECOND STRONGER COLD FRONT MOVES ACROSS THE AREA ON
WEDNESDAY...PRECIP SHOULD COME TO AN END WITH COOLER AND LESS
HUMID AIR MOVING BACK INTO THE REGION. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* ISOLD/SCT TSRA/SHRA THROUGH EARLY EVENING...WITH ISOLATED
ACTIVITY POSSIBLY LINGERING OVERNIGHT.
* ABRUPT WIND SHIFT TO NNE-NELY ARND 00Z WITH WINDS OCNL HIGHER
GUSTS FOR A SHORT TIME FOLLOWING THE PASSAGE OF A LAKE BREEZE
BOUNDARY.
* MVFR VIS POSSIBLE OVERNIGHT.
KREIN
//DISCUSSION...UPDATED 00Z...
A VERY WARM...MOIST AIRMASS IS IN PLACE OVER NRN IL/NWRN. AN
EAST-WEST ORIENTED BOUNDARY IS SLOWLY SAGGING SOUTH THROUGH SRN WI
AND HAS TOUCHED OFF A FEW TS AND SHOULD CONTINUE TO DO SO INTO THE
EVENING AS THE BOUNDARY PUSHES INTO NCNTRL/NWRN IL. A LAKE
BREEZE/BACK COLD FRONT IS PUSHING INLAND OFF OF THE LAKE INTO NERN
IL AND AS OF 23Z HAS ALREADY PUSHED THROUGH UGN/PWK AND SHOULD
REACH ORD JUST BEFORE 00Z AND THEN DPA/MDW RIGHT ARND 00Z. WINDS
WILL ABRUPTLY SHIFT TO NELY WITH OCNL GUSTS ARND 15KT FOR A SHORT
TIME FOLLOWING THE PASSAGE OF THE BOUNDARY. TEMPERATURES ARE ALSO
DROPPING OFF QUICKLY FOLLOWING THE BOUNDARY PASSAGE. THROUGH THE
EVENING...WINDS SHOULD DROP OFF TO LGT/VRBL AS HIGH PRESSURE STILL
COVERS THE WESTERN GREAT LAKES AND A VERY WEAK PRESSURE GRADIENT
WILL SET UP OVERNIGHT. DIMINISHING WINDS AND LOWERING DEWPOINT
DEPRESSIONS SHOULD HELP VIS DROP TO MVFR OR IFR LEVELS OVERNIGHT.
CONDITIONS SHOULD BE RELATIVELY QUIET THROUGH THE DAY TOMORROW AS
HIGH PRESSURE PERSISTS OVER THE REGION. VERY WARM CONDITIONS AND
WEAK WINDS SHOULD ALLOW FOR ANOTHER LAKE BREEZE TO DEVELOP
TOMORROW. TIMING OF THE LAKE BREEZE IS A BIT UNCERTAIN AT THIS
POINT...THROUGH DO FEEL THAT IT WILL PUSH INLAND OF THE CHICAGO
AREA TERMINALS SETTING UP ELY WINDS...BUT EXPECT THAT WINDS SHOULD
REMAIN UNDER 10KT. THE LAKE BREEZE MAY BE THE FOCUS FOR TSRA
TOMORROW AFTERNOON...SO HAVE INTRODUCED A PROB30 TS FOR LATE
TOMORROW AFTERNOON.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* MEDIUM CONFIDENCE IN TSRA/SHRA CHANCES/COVERAGE THROUGH THIS
EVENING. LOW CONFIDENCE OF DIRECT IMPACT AT THE TERMINALS.
* HIGH CONFIDENCE IN WIND SPEED/DIRECTION AND SHORT PERIOD OF
HIGHER GUSTS THROUGH EARLY THIS EVENING.
* MEDIUM CONFIDENCE IN LAKE BREEZE DETAILS TOMORROW AFTERNOON.
* MEDIUM CONFIDENCE IN MVFR VIS DEVELOPING OVERNIGHT AND DURATION.
* LOW TO MEDIUM CONFIDENCE IN TS CHANCES TOMORROW AFTERNOON. LOW
CONFIDENCE IN CHANCES OF DIRECT IMPACT AT THE TERMINALS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SATURDAY...SLIGHT CHANCE OF TSRA IN THE AFTERNOON.
SUNDAY...SLIGHT CHANCE OF TSRA LATE.
MONDAY...CHANCE OF TSRA.
TUESDAY...CHANCE OF TSRA.
WEDNESDAY...CHANCE OF TSRA.
KREIN
&&
.MARINE...
308 PM...A WEAK FRONTAL BOUNDARY WILL MOVE SOUTH OF THE LAKE THIS
EVENING WITH A PERIOD OF NORTH/NORTHEAST WINDS EXPECTED INTO
FRIDAY WHICH WILL SLOWLY DIMINISH FIRST ACROSS THE SOUTHERN PART
OF THE LAKE. WINDS WILL SLOWLY TURN SOUTHERLY FRIDAY NIGHT INTO
SATURDAY. THESE SOUTHERLY WINDS WILL SLOWLY INCREASE INTO THE
10-20 KT RANGE BY SUNDAY AS THE GRADIENT TIGHTENS SOME BETWEEN A
LARGE TROUGH OF LOW PRESSURE OVER THE PLAINS AND LARGE HIGH
PRESSURE OVER ATLANTIC COAST. ITS POSSIBLE WINDS MAY INCREASE INTO
THE 15-25 KT RANGE... ESPECIALLY ON THE NORTHERN PART OF THE LAKE.
A WEAKENING COLD FRONT WILL MOVE ACROSS THE LAKE SUNDAY NIGHT INTO
MONDAY MORNING WITH WINDS SHIFTING NORTHERLY BY MONDAY EVENING. IT
APPEARS WINDS WILL SHIFT BACK TO SOUTHERLY TUESDAY UNTIL A
STRONGER COLD FRONT ARRIVES LATE TUESDAY NIGHT INTO WEDNESDAY...
WHICH WILL SHIFT WINDS TO THE NORTHWEST. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS DES MOINES IA
703 PM CDT THU SEP 3 2015
.UPDATE...
ISSUED AT 656 PM CDT THU SEP 3 2015
ISOLATED SHOWER/STORM WORDING HAS BEEN ADDED N CENTRAL TO E
CENTRAL IA. ELEVATED CONVECTION HAS DEVELOPED ON LEADING EDGE OF
WEAK WARM ADVECTION...LIKELY ROOTED FAIRLY HIGH ABOVE 2KM BASED ON
FORECAST SOUNDINGS. HAVE ONLY ADDED A FEW HOURS AT THIS
POINT...BUT MAY HAVE TO EXTEND AS IT MAY MAINTAIN ITSELF INTO THE
NIGHT WITH TYPICAL NOCTURNAL WARM ADVECTION CYCLE.
&&
.SHORT TERM /TONIGHT/...
ISSUED AT 332 PM CDT THU SEP 3 2015
MAIN FORECAST CONCERN WAS FOCUSED ON TEMPERATURES AND FOG
POTENTIAL OVER NORTHERN IOWA. OVERNIGHT LOWS LOOK TO FINALLY REACH
THE CROSSOVER TEMP BY B/T 07-09Z OVER THE NORTH AND LIKELY SEE FOG
DEVELOP DURING THAT TIME FRAME. NAM/SREF SUGGEST FOG DEVELOPING FROM
MOW TO EST AND POSSIBLY AS FAR SOUTH AS HIGHWAY 20. THE CAVEAT IS
A WEAK SHORTWAVE OVER NEBRASKA/SOUTH DAKOTA MAY BRING IN SOME
HIGHER CLOUDS TOWARDS FRIDAY MORNING...SO ONLY MENTIONED PATCHY
FOG ATOM. THE LATEST HRRR (03.18Z) AND EVEN THE GFS HAVE A HINT
OF CONVECTION DEVELOPING OVER THE NORTHWEST TOWARDS FRIDAY MORNING
IN RESPONSE TO THE LAW DEVELOPING AND ASSOCIATED WITH
AFOREMENTIONED WEAK SHORTWAVE. THINKING THE NAM/ECMWF HAS A BETTER
HANDLE ON TIMING AND LOCATION AND LEFT FORECAST DRY.
.LONG TERM /FRIDAY THROUGH THURSDAY/...
ISSUED AT 332 PM CDT THU SEP 3 2015
PATTERN REMAINS SIMILAR THROUGH THE BEGINNING OF THE MID/LONG RANGE
WITH UPPER RIDGING IN PLACE ALOFT WITH A TROUGH DIGGING INTO THE
WESTERN US. A FEW WEAK IMPULSES WILL MOVE JUST TO THE WEST OF THE
CWA WHICH COULD LEAD TO SOME INCREASED CLOUDINESS...BUT OVERALL
CHANCE OF PRECIPITATION IS SMALL SO HAVE A DRY FORECAST INTO
SATURDAY. UPPER LEVEL RIDGE TO FLATTEN SOME OVER THE WEEKEND AS THE
WESTERN US TROUGH LIFTS NORTHEASTWARD INTO SOUTHERN CANADIAN PRAIRIE
PROVINCES BY LATE SUNDAY. SOUTHERLY FLOW WILL INCREASE AHEAD OF THIS
SYSTEM SATURDAY NIGHT INTO SUNDAY...WITH MOISTURE ADVECTION AND
MOISTURE TRANSPORT BECOMING ORIENTED INTO WESTERN IOWA. MAY SEE SOME
STORMS BUBBLE UP ACROSS THE WESTERN/NORTHWESTERN CWA...BUT OVERALL
WIDESPREAD PRECIPITATION CHANCES NOT EXPECTED UNTIL THE PASSAGE OF
THE COLD FRONT ASSOCIATED WITH THE CANADIAN SYSTEM SUNDAY NIGHT.
THIS FRONT WILL ELIMINATE THE CURRENT HOT AND MUGGY CONDITIONS...AS
H85 TEMPS DROP INTO THE TEENS BEHIND THE FRONT. LONG RANGE IN MODELS
IN SOME DISAGREEMENT INTO NEXT WEEK WITH HOW FAST TO PUSH THE FRONT
SOUTH...WITH THE EC HANGING THE FRONT UP ACROSS SOUTHERN IOWA WITH
CHANCES FOR STORMS CONTINUING INTO MONDAY/MONDAY NIGHT. GFS TRIES TO
PUSH IT INTO MISSOURI...WHICH WOULD KEEP IOWA DRIER MONDAY. FULL
WESTERN US TROUGH TO SHOVE EAST TUESDAY WITH THE FRONT LIFTING
BACK NORTHWARD AS A WARM FRONT LATE MONDAY NIGHT/EARLY TUESDAY
BEFORE A STRONGER COLD FRONT PUSHES THROUGH LATE TUESDAY INTO
TUESDAY NIGHT. H85 TEMPS TO DROP ANOTHER CATEGORY INTO THE LOW
TEENS BEHIND THIS FRONT WITH HIGH PRESSURE EXPECTED TO BUILD IN
FOR THE REST OF THE WEEK. THIS SHOULD LEAD TO MAINLY DRY
CONDITIONS FOR MUCH OF WEDNESDAY INTO THE END OF THE WEEK. MODELS
DO HINT AT A WEAK TROUGH CLIPPING NORTHERN IOWA THURSDAY WHICH
COULD BRING SOME SPRINKLES TO MAINLY NORTHEASTERN IOWA. HAVE A
SMALL AREA OF SLIGHT CHANCE POP FOR THIS FEATURE. OTHERWISE
RELEGATED POPS MAINLY TO THE TIME PERIODS WITH THE FRONTAL
PASSAGES WITH TEMPS EXPECTED TO FALL MORE TOWARD OR SLIGHTLY BELOW
THE SEASONAL AVERAGES.
&&
.AVIATION...03/18Z
ISSUED AT 1229 PM CDT THU SEP 3 2015
ONLY CONCERN THROUGH THE PERIOD WILL BE RADIATION FOG POTENTIAL
NORTH IN VICINITY OF WARM FRONT ALONG IA/MN BORDER. HAVE
ESSENTIALLY FOLLOWED PERSISTENCE AT KMCW WITH CONDITIONS
LIKELY DETERIORATING TO LIFR AGAIN. COULD BE EVEN WORSE WITH LESS
MIXING TODAY BUT DID NOT WANT TO BE THAT AGGRESSIVE AT THIS POINT.
OTHERWISE EXPECT VFR WITH NOTHING BEYOND SCT/BKN MID CLOUDS AT
OTHER LOCATIONS. CURRENT ISOLATED CONVECTION IS NOT AFFECTING TAF
SITES AND SHOULD REMAIN THAT WAY FOR THE SHORT TERM.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...SMALL
SHORT TERM...PODRAZIK
LONG TERM...BEERENDS
AVIATION...CURTIS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
343 PM CDT WED SEP 2 2015
.SHORT TERM...(THIS EVENING THROUGH Thursday)
ISSUED AT 307 PM CDT WED SEP 2 2015
19z sfc map shows low pressure across the northern plains with a
trough extending south into western KS with most of eastern Kansas
now mixed out into the warm sector as remnants of elevated
convection wane. Water vapor loop shows a wave across Nebraska
moving E along the northern periphery of the upper ridge axis.
For tonight, the wave will track into northern MO overnight and may
help to enhance the LLJ which will contribute to modest WAA around
850mb. There is some additional WAA fcst to occur around the 700mb
level as well. Interesting that both the RAP and HRRR and GFS are
showing some small areas of QPF across central KS overnight despite
the 850mb thetae ridge remaining north of the CWA overnight. This
appears to be due to modest lift and saturation around 700-650mb
where even the NAM soundings show saturation after 6z. Fcst
soundings suggest modest elevated CAPE of 100j/kg or less. Other
convective models do not show this weak lift resulting in saturation
or convection so for now will keep the pops below 15 and keep the
fcst dry but something to watch for overnight.
We should see another day much like today on Thursday with 1000-
850mb thickness and temps nearly identical to today so will go with
persistence for temps. Pressure gradient is also similar so look for
another breezy day as well.
.LONG TERM...(Thursday NIGHT THROUGH Wednesday)
ISSUED AT 307 PM CDT WED SEP 2 2015
Thursday night through Saturday...Deep, moist southerly low-level
flow will continue through the period. With stronger south-
southwest flow aloft off to our west and northwest, no
recognizable dynamic feature is depicted in the short range
guidance to focus showers and thunderstorms in eastern KS. Only
possibility would be the remnants of some High Plains convective
cluster that might migrate into north central KS/south central/NE
before dissipating. Would expect any system like that to die out
before affecting our northwestern forecast area.
Saturday night through Wednesday...Strong upper trough over the
Rockies on Saturday evening will move northeast into southern
Manitoba and become an occluded system by Monday morning. While
strong dynamics are well to the north, southern extent of system
is a cold front that moves into central/eastern KS and then
becomes nearly stationary. This will be the focus for thunderstorm
chances late in the weekend into early next week. Medium range
models have some differences in the location of this boundary
already by Monday, but all depict it in the area with periodic
chances of thunderstorms into Tuesday night/Wednesday morning.
Then another strong trough moves across the central U.S. with the
result that the front pushes south of the area by late Wednesday.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z Thursday AFTERNOON)
ISSUED AT 1232 PM CDT WED SEP 2 2015
VFR conditions are expected for the duration of the TAF period at
all terminals. However, wind gusts of 20-25 knots from the south
are expected at all terminals through 1Z this evening. Wind gusts
will also be a concern after 15Z tomorrow morning as 20-25 knot
gusts are expected.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Omitt
LONG TERM...GDP
AVIATION...Omitt/Baerg
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1220 AM CDT WED SEP 2 2015
...Update to aviation forecast discussion...
.SHORT TERM...(THIS EVENING THROUGH Wednesday)
ISSUED AT 339 PM CDT TUE SEP 1 2015
The upper levels show a broad upper ridge over the eastern CONUS
with a longwave trough just making its way into the Pacific
Northwest. Currently, most Radar sites across the Central Plains
remain quiet with only some rain showers over southeastern South
Dakota. Cloud tops have progressively cooled throughout the day
indicating that storms have been dissipating. This area of showers
appears to be in advance of a mid to upper level low amplitude
shortwave that is showing signs of weakening with decreasing
vorticity as it lifts further to the northeast from the lee trough
region of the Rockies.
Daytime mixing has allowed for some gusty winds at the surface today
as we are still under plenty of sunshine over northeastern KS. This
is expected to continue until tonight as winds calm as we begin to
lose insolation and the source of heating at the surface. Still
expecting that the previously mentioned shortwave will have at least
minor impacts tonight over north central and northeastern KS
tonight into the early morning hours Wednesday. Most short-term
high resolution guidance, such as the HRRR and RAP, suggest that
weak isentropic lift at around 310K level and a little extra
enhancement from the LLJ around 850mb will help create some small
areas of precip. With at least some midlevel instability due to
the remnants of the shortwave, there could be some elevated
thunderstorms. It is possible with drier low-levels per NAM and
RAP soundings that there could be some areas of stronger winds
with the more enhanced areas of thunderstorms and precip.
Expecting that tomorrow will be similar to today. As the clouds
from over night clear, expect mixing to occur once again with
highs climbing into the low 90s. Depending on how many clouds
remain, temps may need to be revised up a bit. As for lows
tonight, do expect temps to reach lower 70s which is up a bit due
to the expected cloud cover overnight.
.LONG TERM...(Wednesday NIGHT THROUGH Tuesday)
ISSUED AT 339 PM CDT TUE SEP 1 2015
Wednesday night through Friday afternoon...More of the same sensible
weather with highs in the 90s and lows in the 70s. Plume of
moisture continues to move into the four corners and southern and
Central Rockies as the western trof absorbs tropical energy from
near Baja. Weak wave may generate some isolated overnight showers
or a storm northwest late Wednesday night into early Thursday
morning, otherwise the ridge noses northward and keeps most of the
area dry and warm for the mid term period.
Friday night through Tuesday...Friday night and Saturday look to
be dry, before chances for precipitation start to increase Sunday
through Tuesday. An upper level system moving over the NW CONUS
Saturday will progress east along with an associated cold front.
With southerly winds advecting ample moisture into the region and
an advancing cold front, expect showers and storms to develop in
NE Kansas mainly early Monday morning through Tuesday. Models also
seem to be in better agreement with this timing. Cooler
temperatures are expected as that front passes, with lows in the
mid 60s Monday night and highs topping out in the low 80s on
Tuesday.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z Wednesday NIGHT)
ISSUED AT 1219 AM CDT WED SEP 2 2015
For the 06z TAFs, VFR conditions are expected through the period.
Expect some isolated to scattered showers and isolated
thunderstorms near the TAF sites overnight into Wednesday
morning. With the low-level jet axis centered over central KS tonight, there is the
potential for some brief low-level wind shear concerns, especially
near KMHK as it is located closer to this increasing low-level jet.
Cannot rule out the potential for some borderline low-level wind
shear concerns near KTOP/KFOE so will continue to monitor this
potential as well. Otherwise, expect precipitation to exit the TAF site
through the morning hours with increasing southerly winds through
the afternoon.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Drake
LONG TERM...67/Heller
AVIATION...Hennecke
AREA FORECAST DISCUSSION
NWS PADUCAH KY
218 PM CDT WED SEP 2 2015
.SHORT TERM...(This evening through Friday Night)
Issued at 218 PM CDT WED SEP 2 2015
Upper level disturbance in the lower Mississippi River Valley was
causing some isolated showers to our southwest this
afternoon...with a few cells getting fairly close to our SEMO
counties. The RUC and HRRR models seem to be overdone by showing
some activity developing over us this afternoon. Cu field looks
fairly shallow right now, but will continue to monitor for any
isolated development. The aforementioned upper level feature will
shift east tonight.
The 12Z model consensus continues to advertise high pressure at the
surface and aloft that will keep the area mainly dry through
Friday. The only exception to this may be on Thursday night into
Friday when some energy may drop south on the east side of the
upper high. Not every model is advertising any QPF and there
really isnt too much moisture to work with other than a shallow
layer between 850-700mb. But an isolated or widely scattered storm
is possible. Too low of a probability to mention in the forecast
but would not be surprised to see a few cells out there.
Temperatures will remain above normal. Looks like low level temps
rise a degree or so for tomorrow and given the abundant
sunshine...believe we could be a tad warmer on Thursday. Some of the
guidance supports this notion as well. We could see temperatures
drop a degree or so in the eastern sections on Friday though as the
upper ridge breaks down a bit there. However, it will still be
fairly warm. Lower 90s for highs and upper 60s to around 70 degrees
for lows looks to be the norm for the next few days along with light
and variable winds.
.LONG TERM...(Saturday through Wednesday)
Issued at 218 PM CDT WED SEP 2 2015
Average confidence in the short term period due to model
differences, especially toward the end of the period. Very few
changes to the long term with not much to discuss.
At the beginning of the long term period, weak high pressure at the
surface and aloft will be the predominant features affecting our
CWA`s weather, therefore dry conditions are forecast for the first
couple of days.
Beyond that and through most of the long term period, the
development of weaknesses or slight shifting of the axis of the
aforementioned high pressure will make it possible for isolated to
scattered convection to pop up given the moisture and instability
already in place.
With the approach and passage of a cold front, precipitation chances
slowly increase and eventually overspread the entire CWA by the end
of the period.
Above normal temperatures at the beginning of the period will slowly
cool back to near normal readings by the end of the period.
&&
.AVIATION...
Issued at 218 PM CDT WED SEP 2 2015
Surface high pressure will keep winds light and variable through
the day. As they go calm overnight, some at least MVFR fog is
likely to develop at all sites, similar to this morning. More
cumulus is expected again on Thursday...similar to the level they
are at today. Winds will be light and variable again Thursday...at
least prior to 18Z.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
344 PM CDT WED SEP 2 2015
.SHORT TERM... NOT MUCH HAS CHANGED TO THE UPPER LEVEL PATTERN IN
GENERAL ACROSS THE SOUTHEASTERN UNITED STATES HAS CHANGED MUCH. BUT
ALL IT TOOK WAS AN INVERTED TROUGH CENTERED JUST TO THE WEST OF THE
FORECAST AREA TO SHIFT SLIGHTLY EAST TO ALLOW MORE MOISTURE IN FROM
THE GULF. THE RESULTS FROM THIS CHANGE CAN CLEARLY BE SEEN ON RADAR.
A WIDE BLANKET OF LIGHT TO MODERATE RAIN EXTENDS FROM THE OFFSHORE
WATERS SOUTH OF LOUISIANA NORTHWARD TO INTERSTATE 12. THE ATMOSPHERE
APPEARS TO BE SLIGHTLY MORE STABLE INLAND VS ALONG THE COAST WHERE
MOST OF THE LIGHTNING HAS BEEN OCCURRING. NORTHWARD PROGRESSION OF
RAINFALL ACROSS THE CWA SHOULD BE JUST ABOUT DONE. THE HRRR HAS BEEN
PERFORMING WELL TODAY AND IT SUGGESTS MUCH OF THE ACTIVITY SHOULD BE
ON A DOWNWARD TREND SOON AND MOST OF THE INLAND SHOWERS DISSIPATED
BY 00Z-02Z. AFTER THAT...FAIRLY QUIET DURING THE EVENING HOURS WITH
SHOWERS REDEVELOPING OFFSHORE ALONG THE LA COAST EARLY TOMORROW
MORNING AND THEN A SIMILAR REPEAT FOR THURSDAY. HAVE INCREASED RAIN
CHANCES FOR PORTIONS OF THE CWA SOUTH OF LAKE PONTCHARTRAIN TO THE
COAST TO ACCOUNT FOR THIS.
.LONG TERM... THE UPPER LEVEL PATTERN OVER THE CWA WILL REMAIN
SIMILAR THROUGH THE WEEKEND WITH WEAKNESS ALOFT WHICH WILL PROMOTE
DAILY POPS IN THE 30 TO 50 PERCENT RANGE. HIGH PRESSURE WILL TRY TO
REBUILD ITSELF TO THE WEST OF THE REGION EARLY NEXT WEEK BUT STILL
BEING EAST OF THIS AREA IN LA/MS...LIKELY TO HAVE CONTINUED SHOWER
AND THUNDERSTORMS DEVELOP IN THE AFTERNOONS.
MEFFER
&&
.AVIATION...
EXPECT VFR CONDITIONS TO DOMINATE THE PERIOD ACROSS ALL TERMINALS.
IN THE SHORT TERM THOUGH QUITE EXTENSIVE MID AND HIGH CLOUD DECK
ACROSS MUCH OF THE AREA FROM THUNDERSTORMS THAT HAVE MOVED ONSHORE
FROM THE GULF DURING THE MORNING HOURS. THE CONVECTION THAT WILL
IMPACT MOST TERMINALS IS DOING SO AT THIS TIME. MOST ACTIVITY SHOULD
DISSIPATE BY AROUND 00Z-02Z BEFORE RETURNING TOMORROW.
MEFFER
&&
.MARINE...
RELATIVELY BENIGN CONDITIONS FOR THE NEXT SEVERAL DAYS WITH A WEAK
PRESSURE PATTERN CONTROLLING THE WEATHER. WINDS GENERALLY LESS THAN
10 KNOTS WITH SEAS 2 FEET OR LESS. SCATTERED CONVECTION POSSIBLE
JUST ABOUT EVERY DAY OF FORECAST AFTER TODAY. THIS ACTIVITY MAY
PRODUCE WIND GUSTS TO 30 KNOTS OR BETTER AT TIMES AS IT MOVES OUT OF
THE GULF. 35
&&
.DECISION SUPPORT...
DSS CODE....GREEN.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...NONE.
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED WATCH/WARNING/ADVISORY
ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE RISK SVR AND/OR DIRECT
TROPICAL THREATS; EVENTS OF NATIONAL SIGNIFICANCE
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 72 94 73 94 / 10 30 10 30
BTR 72 92 74 92 / 10 30 10 30
ASD 76 90 76 90 / 20 50 20 30
MSY 77 88 77 89 / 20 50 20 40
GPT 77 89 78 90 / 20 50 20 30
PQL 76 90 76 90 / 20 50 20 30
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
148 PM CDT WED SEP 2 2015
.UPDATE...
BUMP HIGHS ANOTHER CATEGORY AND SHAVE DEEP E TX POPS.
&&
.DISCUSSION...
AIR TEMPERATURES HAVE TAKEN A BIG JUMP OVER THE LAST COUPLE OF
HOURS AND WITH THE THICK MID DECK ALREADY NORTH OF SHREVEPORT THE
LOWER 90S WOULD NOT LIKELY HOLD. ALSO...WE HAVE TWEAKED POPS A
TAD WHERE CU FIELD HAS BEEN SLUGISH TO DEVELOP ANY TOWERS. /24/
&&
.PREV DISCUSSION... /ISSUED 1158 AM CDT WED SEP 2 2015/
AVIATION...
MID LVL CLOUD DECKS ACROSS THE AREA INHIBITING CUMULUS DEVELOPMENT
IN MOISTER AIR UNDERNEATH. CONVECTION THUS FAR TODAY HAS REMAINED
JUST OFFSHORE IN GULF AND NE MOVMT OF CELLS COULD POSSIBLY TRAJECT
TOWARDS KMLU LATER THIS AFTN...SO PLACED TSTM VCNTY AT THAT
TERMINAL BUT NONE ELSEWHERE. FOG AND LOW CLOUDS TONIGHT LIMITED IN
LACK OF SOUTHERLY FLOW OR RECENT FOG DEVELOPMENT ACROSS AREA...BUT
IF SO...KLFK WOULD BE MOST LIKELY TERMINAL TO SEE ANY TEMPO MVFR
CONDITIONS OVERNIGHT. LGT VRBL WINDS ACROSS AREA TO REMAIN UNTIL
AT LEAST 03/15Z WITH ONLY SE WINDS AROUND 5 KTS AFTER THAT./VII/.
PREV DISCUSSION... /ISSUED 1137 AM CDT WED SEP 2 2015/
UPDATE...
A FEW MINOR CHANGES TO AFTERNOON POPS/SKY AND HIGH TEMPERATURES.
DISCUSSION...
ADD 10 AT 10 CST RULE WITH OBS RANGING ALL THROUGH THE 80S. A
DENSE MID DECK IS WORKING OVER THE HEART OF THE ARKLATEX WITH LOW
80S AND LIGHT OR CALM SFC WINDS. RUSTON AND MONROE ARE IN THE
UPPER 80S WITH A GOOD DEAL MORE SUNSHINE THIS MORNING. OUR RADAR
HAS A CLEAN SWEEP AND WITH LIMITED HEATING AND THAT MAY BE
THROUGH THE LUNCH HOUR.
OUR SOUNDING SHOWED MOISTURE INTO THE MID LEVELS...BUT VERY DRY
ABOVE AN INVERSION AT 18KFT. IT IS LIKELY THAT THE NE FLOW ABOVE
THE INVERSION HAS WORKED DOWN A BIT LOOKING AT THE WATER VAPOR.
ANY THUNDERSTORMS TODAY WILL BE LOW TOPPED AND PERHAPS FEW AND FAR
BETWEEN. MIDDECK SHOWERS ARE MORE LIKELY UNTIL WE SEE BETTER
HEATING THIS AFTERNOON. THE VAPOR SHOWS THE DRY AIR SPREADING SE
FOR THE LAST FEW HOURS...BUT HAS SLOWED ITS MOTION. THERE IS A
LITTLE VORT WORKING UP ACROSS W LA IN OVER TOLEDO BEND COUNTRY.
THIS MAY HELP WITH SOME CHANCE POPS FOR I-20 CORRIDOR LATER WITH
MORE HEATING AS THE MID DECK MOVES FARTHER NW.
THE HRRR SHOWS DECENT COVERAGE AND IS WHY WE LEFT CHANCE POPS.
SLIGHT CHANCE MAY BE A MORE LIKELY EVENT IF THAT LITTLE VORT FAILS
TO SPREAD DEEPER TROPICAL MOISTURE BACK INTO THAT DRIER AIR. THE
CHANCE FOR RAIN STILL LOOKS TO DECLINE INTO THE NEXT FEW DAYS AS
THE MAIN GULF LOW MOVES EASTWARD...TAKING THE TROPICAL CONNECTION
OUT OF REACH. /24/
PREV DISCUSSION... /ISSUED 412 AM CDT WED SEP 2 2015/
DISCUSSION...
WATER VAPOR IMAGERY CONTINUES TO DEPICT A WEAK UPPER LEVEL LOW
NEAR GALVESTON BAY THIS MORNING WITH A SHEAR AXIS EXTENDING NWRD
ACROSS DEEP E TX...N LA...AND SE AR. MID AND HIGH CLOUDS CONTINUE
TO BLANKET THESE AREAS WHILE POINTS ALONG AND NORTH OF THE I-30
CORRIDOR ARE SKC. AS MOISTURE REMAINS QUITE ABUNDANT OVER THE SE
HALF OF THE REGION TODAY...EXPECT SHWRS AND TSTMS TO INCREASE AS
WE MOVE INTO THE AFTERNOON HOURS WITH THE ADDED INSTABILITY FROM
HEATING. USING PERSISTENCE AS A GUIDE...DO EXPECT CLOUD COVER TO
HOLD DOWN TEMPERATURES SLIGHTLY MUCH LIKE YESTERDAY WITH UPPER 80S
AND LOWER 90S EXPECTED.
RAIN CHANCES WILL BEGIN TO DROP OFF AS WE HEAD INTO LATE WEEK AND
THE LABOR DAY WEEKEND AS UPPER RIDGING BECOMES MORE INFLUENTIAL IN
OUR WEATHER PATTERN...SENDING TEMPERATURES HIGHER INTO THE MID 90S
AND POSSIBLY EVEN UPPER 90S FOR SOME AREAS OVER THE WEEKEND. SOME
DIURNALLY DRIVEN CONVECTION CANNOT BE COMPLETELY RULED OUT BUT IT
WILL BE ISOLATED AT BEST WITH SEA BREEZE ACTIVITY ACROSS MAINLY
OUR SRN ZONES.
RELIEF FROM THE LATE SUMMER HEAT WILL LIKELY HAVE TO WAIT UNTIL
THURSDAY OF NEXT WEEK WITH AN ADVANCING COLD FRONT. THIS WILL ALSO
PROVIDE OUR NEXT BEST CHANCE AT SEEING WIDESPREAD SHWRS AND TSTMS
ACROSS THE REGION. EXPECT NOTICEABLY COOLER AND DRIER AIR IN THE
WAKE OF THIS FRONT...WITH TEMPERATURES LIKELY A FEW DEGREES BELOW
NORMAL BY THE END OF NEXT WEEK. /19/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 94 73 95 74 / 30 20 20 10
MLU 96 72 96 73 / 30 20 20 10
DEQ 94 69 94 70 / 20 10 10 10
TXK 94 71 94 73 / 20 20 10 10
ELD 93 70 95 72 / 30 20 20 10
TYR 92 73 94 73 / 20 10 20 10
GGG 93 72 94 73 / 20 10 20 10
LFK 94 71 93 72 / 20 20 30 20
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
24/07/19
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1158 AM CDT WED SEP 2 2015
.AVIATION...
MID LVL CLOUD DECKS ACROSS THE AREA INHIBITING CUMULUS DEVELOPMENT
IN MOISTER AIR UNDERNEATH. CONVECTION THUS FAR TODAY HAS REMAINED
JUST OFFSHORE IN GULF AND NE MOVMT OF CELLS COULD POSSIBLY TRAJECT
TOWARDS KMLU LATER THIS AFTN...SO PLACED TSTM VCNTY AT THAT
TERMINAL BUT NONE ELSEWHERE. FOG AND LOW CLOUDS TONIGHT LIMITED IN
LACK OF SOUTHERLY FLOW OR RECENT FOG DEVELOPMENT ACROSS AREA...BUT
IF SO...KLFK WOULD BE MOST LIKELY TERMINAL TO SEE ANY TEMPO MVFR
CONDITIONS OVERNIGHT. LGT VRBL WINDS ACROSS AREA TO REMAIN UNTIL
AT LEAST 03/15Z WITH ONLY SE WINDS AROUND 5 KTS AFTER THAT./VII/.
&&
.PREV DISCUSSION... /ISSUED 1137 AM CDT WED SEP 2 2015/
UPDATE...
A FEW MINOR CHANGES TO AFTERNOON POPS/SKY AND HIGH TEMPERATURES.
DISCUSSION...
ADD 10 AT 10 CST RULE WITH OBS RANGING ALL THROUGH THE 80S. A
DENSE MID DECK IS WORKING OVER THE HEART OF THE ARKLATEX WITH LOW
80S AND LIGHT OR CALM SFC WINDS. RUSTON AND MONROE ARE IN THE
UPPER 80S WITH A GOOD DEAL MORE SUNSHINE THIS MORNING. OUR RADAR
HAS A CLEAN SWEEP AND WITH LIMITED HEATING AND THAT MAY BE
THROUGH THE LUNCH HOUR.
OUR SOUNDING SHOWED MOISTURE INTO THE MID LEVELS...BUT VERY DRY
ABOVE AN INVERSION AT 18KFT. IT IS LIKELY THAT THE NE FLOW ABOVE
THE INVERSION HAS WORKED DOWN A BIT LOOKING AT THE WATER VAPOR.
ANY THUNDERSTORMS TODAY WILL BE LOW TOPPED AND PERHAPS FEW AND FAR
BETWEEN. MIDDECK SHOWERS ARE MORE LIKELY UNTIL WE SEE BETTER
HEATING THIS AFTERNOON. THE VAPOR SHOWS THE DRY AIR SPREADING SE
FOR THE LAST FEW HOURS...BUT HAS SLOWED ITS MOTION. THERE IS A
LITTLE VORT WORKING UP ACROSS W LA IN OVER TOLEDO BEND COUNTRY.
THIS MAY HELP WITH SOME CHANCE POPS FOR I-20 CORRIDOR LATER WITH
MORE HEATING AS THE MID DECK MOVES FARTHER NW.
THE HRRR SHOWS DECENT COVERAGE AND IS WHY WE LEFT CHANCE POPS.
SLIGHT CHANCE MAY BE A MORE LIKELY EVENT IF THAT LITTLE VORT FAILS
TO SPREAD DEEPER TROPICAL MOISTURE BACK INTO THAT DRIER AIR. THE
CHANCE FOR RAIN STILL LOOKS TO DECLINE INTO THE NEXT FEW DAYS AS
THE MAIN GULF LOW MOVES EASTWARD...TAKING THE TROPICAL CONNECTION
OUT OF REACH. /24/
PREV DISCUSSION... /ISSUED 412 AM CDT WED SEP 2 2015/
DISCUSSION...
WATER VAPOR IMAGERY CONTINUES TO DEPICT A WEAK UPPER LEVEL LOW
NEAR GALVESTON BAY THIS MORNING WITH A SHEAR AXIS EXTENDING NWRD
ACROSS DEEP E TX...N LA...AND SE AR. MID AND HIGH CLOUDS CONTINUE
TO BLANKET THESE AREAS WHILE POINTS ALONG AND NORTH OF THE I-30
CORRIDOR ARE SKC. AS MOISTURE REMAINS QUITE ABUNDANT OVER THE SE
HALF OF THE REGION TODAY...EXPECT SHWRS AND TSTMS TO INCREASE AS
WE MOVE INTO THE AFTERNOON HOURS WITH THE ADDED INSTABILITY FROM
HEATING. USING PERSISTENCE AS A GUIDE...DO EXPECT CLOUD COVER TO
HOLD DOWN TEMPERATURES SLIGHTLY MUCH LIKE YESTERDAY WITH UPPER 80S
AND LOWER 90S EXPECTED.
RAIN CHANCES WILL BEGIN TO DROP OFF AS WE HEAD INTO LATE WEEK AND
THE LABOR DAY WEEKEND AS UPPER RIDGING BECOMES MORE INFLUENTIAL IN
OUR WEATHER PATTERN...SENDING TEMPERATURES HIGHER INTO THE MID 90S
AND POSSIBLY EVEN UPPER 90S FOR SOME AREAS OVER THE WEEKEND. SOME
DIURNALLY DRIVEN CONVECTION CANNOT BE COMPLETELY RULED OUT BUT IT
WILL BE ISOLATED AT BEST WITH SEA BREEZE ACTIVITY ACROSS MAINLY
OUR SRN ZONES.
RELIEF FROM THE LATE SUMMER HEAT WILL LIKELY HAVE TO WAIT UNTIL
THURSDAY OF NEXT WEEK WITH AN ADVANCING COLD FRONT. THIS WILL ALSO
PROVIDE OUR NEXT BEST CHANCE AT SEEING WIDESPREAD SHWRS AND TSTMS
ACROSS THE REGION. EXPECT NOTICEABLY COOLER AND DRIER AIR IN THE
WAKE OF THIS FRONT...WITH TEMPERATURES LIKELY A FEW DEGREES BELOW
NORMAL BY THE END OF NEXT WEEK. /19/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 73 95 74 96 / 20 20 10 10
MLU 72 96 73 97 / 20 20 10 20
DEQ 69 94 70 94 / 10 10 10 10
TXK 71 94 73 96 / 20 10 10 10
ELD 70 95 72 95 / 20 20 10 10
TYR 73 94 73 95 / 10 20 10 10
GGG 72 94 73 94 / 10 20 10 10
LFK 71 93 72 93 / 20 30 20 20
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1137 AM CDT WED SEP 2 2015
.UPDATE...
A FEW MINOR CHANGES TO AFTERNOON POPS/SKY AND HIGH TEMPERATURES.
&&
.DISCUSSION...
ADD 10 AT 10 CST RULE WITH OBS RANGING ALL THROUGH THE 80S. A
DENSE MID DECK IS WORKING OVER THE HEART OF THE ARKLATEX WITH LOW
80S AND LIGHT OR CALM SFC WINDS. RUSTON AND MONROE ARE IN THE
UPPER 80S WITH A GOOD DEAL MORE SUNSHINE THIS MORNING. OUR RADAR
HAS A CLEAN SWEEP AND WITH LIMITED HEATING AND THAT MAY BE
THROUGH THE LUNCH HOUR.
OUR SOUNDING SHOWED MOISTURE INTO THE MID LEVELS...BUT VERY DRY
ABOVE AN INVERSION AT 18KFT. IT IS LIKELY THAT THE NE FLOW ABOVE
THE INVERSION HAS WORKED DOWN A BIT LOOKING AT THE WATER VAPOR.
ANY THUNDERSTORMS TODAY WILL BE LOW TOPPED AND PERHAPS FEW AND FAR
BETWEEN. MIDDECK SHOWERS ARE MORE LIKELY UNTIL WE SEE BETTER
HEATING THIS AFTERNOON. THE VAPOR SHOWS THE DRY AIR SPREADING SE
FOR THE LAST FEW HOURS...BUT HAS SLOWED ITS MOTION. THERE IS A
LITTLE VORT WORKING UP ACROSS W LA IN OVER TOLEDO BEND COUNTRY.
THIS MAY HELP WITH SOME CHANCE POPS FOR I-20 CORRIDOR LATER WITH
MORE HEATING AS THE MID DECK MOVES FARTHER NW.
THE HRRR SHOWS DECENT COVERAGE AND IS WHY WE LEFT CHANCE POPS.
SLIGHT CHANCE MAY BE A MORE LIKELY EVENT IF THAT LITTLE VORT FAILS
TO SPREAD DEEPER TROPICAL MOISTURE BACK INTO THAT DRIER AIR. THE
CHANCE FOR RAIN STILL LOOKS TO DECLINE INTO THE NEXT FEW DAYS AS
THE MAIN GULF LOW MOVES EASTWARD...TAKING THE TROPICAL CONNECTION
OUT OF REACH. /24/
&&
.PREV DISCUSSION... /ISSUED 654 AM CDT WED SEP 2 2015/
AVIATION...
FOR THE 02/12Z TAFS...PATCHY -DZ/-RA WILL AFFECT PORTIONS OF N
CNTRL LA EARLY IN THE TAF PERIOD MAINLY S OF I-20 AND E OF I-49.
ADDITIONAL ISOLATED TO WIDELY SCATTERED CONVECTION SHOULD AROUND
MIDDAY IN ASSOCIATION WITH AN UPPER TROUGH NEAR GALVESTON BAY.
SHWRS/TSTMS SHOULD LARGELY DISSIPATE BY 03/01Z. VFR CONDITIONS
SHOULD GENERALLY PREVAIL WITH THE EXCEPTION OF PATCHY FOG AT
KELD...WHICH SHOULD DISSIPATE BY 02/15Z...AND ANOTHER ROUND OF
PATCHY FOG WHICH MAY AFFECT KLFK NEAR THE END OF THE TAF PERIOD.
/09/
PREV DISCUSSION... /ISSUED 412 AM CDT WED SEP 2 2015/
DISCUSSION...
WATER VAPOR IMAGERY CONTINUES TO DEPICT A WEAK UPPER LEVEL LOW
NEAR GALVESTON BAY THIS MORNING WITH A SHEAR AXIS EXTENDING NWRD
ACROSS DEEP E TX...N LA...AND SE AR. MID AND HIGH CLOUDS CONTINUE
TO BLANKET THESE AREAS WHILE POINTS ALONG AND NORTH OF THE I-30
CORRIDOR ARE SKC. AS MOISTURE REMAINS QUITE ABUNDANT OVER THE SE
HALF OF THE REGION TODAY...EXPECT SHWRS AND TSTMS TO INCREASE AS
WE MOVE INTO THE AFTERNOON HOURS WITH THE ADDED INSTABILITY FROM
HEATING. USING PERSISTENCE AS A GUIDE...DO EXPECT CLOUD COVER TO
HOLD DOWN TEMPERATURES SLIGHTLY MUCH LIKE YESTERDAY WITH UPPER 80S
AND LOWER 90S EXPECTED.
RAIN CHANCES WILL BEGIN TO DROP OFF AS WE HEAD INTO LATE WEEK AND
THE LABOR DAY WEEKEND AS UPPER RIDGING BECOMES MORE INFLUENTIAL IN
OUR WEATHER PATTERN...SENDING TEMPERATURES HIGHER INTO THE MID 90S
AND POSSIBLY EVEN UPPER 90S FOR SOME AREAS OVER THE WEEKEND. SOME
DIURNALLY DRIVEN CONVECTION CANNOT BE COMPLETELY RULED OUT BUT IT
WILL BE ISOLATED AT BEST WITH SEA BREEZE ACTIVITY ACROSS MAINLY
OUR SRN ZONES.
RELIEF FROM THE LATE SUMMER HEAT WILL LIKELY HAVE TO WAIT UNTIL
THURSDAY OF NEXT WEEK WITH AN ADVANCING COLD FRONT. THIS WILL ALSO
PROVIDE OUR NEXT BEST CHANCE AT SEEING WIDESPREAD SHWRS AND TSTMS
ACROSS THE REGION. EXPECT NOTICEABLY COOLER AND DRIER AIR IN THE
WAKE OF THIS FRONT...WITH TEMPERATURES LIKELY A FEW DEGREES BELOW
NORMAL BY THE END OF NEXT WEEK. /19/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 91 73 95 74 / 30 20 20 10
MLU 94 72 96 73 / 30 20 20 10
DEQ 93 69 94 70 / 20 10 10 10
TXK 92 71 94 73 / 20 20 10 10
ELD 92 70 95 72 / 30 20 20 10
TYR 92 73 94 73 / 20 10 20 10
GGG 92 72 94 73 / 20 10 20 10
LFK 94 71 93 72 / 40 20 30 20
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
24/09/19
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
838 PM EDT THU SEP 3 2015
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 330 PM EDT THU SEP 3 2015
SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE ACROSS LOWER
MICHIGAN THROUGH SATURDAY. THE CLOUDS AND SHOWERS WILL HOLD HIGHS
AROUND 80 FRIDAY BEFORE THE TEMPERATURE CLIMBS BACK TO THE MID 80S
FOR THE REMAINDER OF THE HOLIDAY WEEKEND. COOLER WEATHER IS EXPECTED
BY THE MIDDLE OF NEXT WEEK.
&&
.UPDATE...
ISSUED AT 838 PM EDT THU SEP 3 2015
I UPDATED OUR FORECAST AND GRIDS TO DROP THE MENTION OF
PRECIPITATION OVER MOST OF OUR CWA TONIGHT. AS I SEE IT THE
CONVECTIVE LINE CONTINUES TO SINK SOUTH WITH TIME AND SHOULD BE
OUT OF OUR CWA TOTALLY BY MIDNIGHT. THE RAP MODEL SHOWS THE 700 MB
LOW...CURRENTLY CENTERED NEAR LAKE HURON BY APN...MOVES SLOWLY
WESTWARD...REACHING TO NEAR TVC BY MORNING. THAT KEEPS MOST OF OUR
CWA IN THE DRY WESTERLY FLOW ALL NIGHT LONG. THE DEEP MOISTURE IS
EAST OF LANSING BY 9 PM. THE MOST UNSTABLE CAPE ON THE RAP13
MODEL DROPS SOUTH OVER TIME TOO... WHICH GOES ALONG WITH THE IDEA
OF NO SIGNIFICANT CONVECTION TONIGHT. ONLY AREAS NEAR THE 700 MB
LOW MAY SEE SOME LIGHT WRAP AROUND RAIN SHOWERS (NEAR AND NORTH OF
ROUTE 10).
AS FOR FOG DEVELOPING TONIGHT...THIS COULD BE A SIGNIFICANT
FORECAST ISSUE. THERE IS AN AREA OF THICK LOW CLOUDS DROPPING
SOUTH TO NEAR I-96...AS 0F 8 PM THIS EVENING. DEPENDING ON JUST
HOW FAR SOUTH THEY GET WILL DECIDE HOW DENSE THE FOG GETS TONIGHT.
WITH ALL THE RAIN TODAY AND LIGHT WINDS IF THE SKIES STAYED MOSTLY
CLEAR WE COULD BE LOOKING AT DENSE FOG BY SUNRISE. LIKELY IF THIS
HAPPENS IT WOULD BE NEAR I-94.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 330 PM EDT THU SEP 3 2015
FORECAST CONCERNS DEAL WITH THE CONVECTIVE POTENTIAL THROUGH
SATURDAY.
RADAR IMAGERY SHOWS A COUPLE OF BROKEN LINES OF CONVECTION. THE
FIRST EXTENDS FROM MOUNT PLEASANT WEST TO NEWAYGO COUNTY. THE SECOND
IS FARTHER SOUTH FROM NEAR ST JOHNS TO MIDDLEVILLE. THE SOUTHERN
LINE APPEARS TO BE NEAR A WEAK COLD FRONT THAT IS WASHING OUT.
FARTHER NORTH A WELL DEFINED CIRCULATION ASSOCIATED WITH AN UPPER
LOW THAT WILL LINGER OVER LOWER MICHIGAN THROUGH SATURDAY. SBCAPE
AROUND 2500 J/KG COUPLED WITH SHEAR AROUND 30 KTS IS ENABLING A FEW
STORMS TO BECOME ORGANIZED. AS THE SUN SETS WE/LL LOSE SOME
INSTABILITY AND THE CONVECTION SHOULD WANE A BIT. HOWEVER THE UPPER
LOW/TROUGH WILL LINGER OVER THE CWA THROUGH SATURDAY. SHEAR VALUES
AROUND 15KTS ARE PROGD FRIDAY ACROSS THE CWA SO WE DON/T ANTICIPATE
SVR STORMS BUT CAN`T RULE OUT A STRONG ONE OR TWO DUE TO DECENT
INSTABILITY.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 330 PM EDT THU SEP 3 2015 IMPACT WEATHER IN THE EXTENDED
PERIOD CENTERS AROUND THE SLOW MOVING FRONT THAT MAY BRING COPIOUS
RAINS FROM MONDAY TO EARLY WEDNESDAY.
ONLY A FEW TWEAKS WERE MADE TO THE BLENDED FORECAST...MAINLY TO SLOW
THE FRONT DOWN A BIT EARLY IN THE WEEK PER THE SLOWER 12Z ECMWF THEN
END THE CHANCE FOR POPS LATE WEDNESDAY WHICH THE 12Z GUIDANCE AGREES
ON. GIVEN THE LONG DURATION AND HIGH PWATS...WOULD NOT BE SURPRISED
TO SEE WIDESPREAD 2 TO 3 INCH RAINFALL FROM MONDAY TO EARLY
WEDNESDAY.
TEMPERATURES ON MONDAY WILL BE TRICKY AS HIGH COULD BE ANYWHERE FROM
AROUND 80 TO NEAR 90 DEPENDING ON HOW EXTENSIVE THE CLOUDS ARE. WENT
MIDDLE OF THE ROAD FOR NOW.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 806 PM EDT THU SEP 3 2015
I AM THINKING ALL TAF SITES WILL BECOME IFR TONIGHT AND IMPROVE TO
MVFR CIGS AT BEST BY MIDDAY FRIDAY. I DO NOT EXPECT MUCH RAIN
THROUGH JUST A LOT OF LOW CLOUDS AND FOG.
CURRENTLY THE CONVECTIVE BOUNDARY THAT HAS BEEN FIRING
THUNDERSTORMS MOST OF THE DAY IS MOVING SOUTH OF I-94. THIS IS
MORE THAN JUST A COOL POOL EVENT...THERE IS A COLD FRONT
ASSOCIATED WITH AN UPPER LOW THAT WILL BE IN NO HURRY GO GO
ANYWHERE. SINCE THE UPPER LOW WILL NOT BE MOVING MUCH IN THE NEXT
24 HOURS... WE WILL STAY IN THE COOL AIR. ALSO WORRY OF NOTE IS
ALL THE IFR CIGS WITH STRATUS CLOUDS CURRENTLY OCCURRING NORTH OF
I-96. THIS TO IS RELATED TO THE UPPER LOW. MY SPIN IS THE STRATUS
WILL EXPAND OVERNIGHT AND FOG WILL DEVELOP. THE QUESTION IS WHICH
HAPPENS FIRST. IF THE STRATUS GETS TO THE TAF SITES FIRST THERE
WILL LIKELY NOT BE DENSE FOG BY MORNING. IF THE STRATUS COMES IN
LATER...THEN THERE WILL BE TIME FOR THE FOG TO BECOME DENSE. AT
THIS POINT IT WOULD SEEM THE I-94 TAF SITES ARE FAR ENOUGH AWAY
FROM THE STRATUS TO ALLOW DENSE FOG TO FROM. TAF SITES NEAR TO
I-96 MAY GET THE STRATUS FIRST. EITHER WAY WE HAVE IFR IN THE
MORNING AT ALL TAF SITES. SINCE THE UPPER LOW IS GOING NO WHERE
FAST...I AM THINKING THE LOW CLOUDS WILL BE SLOW TO BURN OFF
(STATIONARY FRONT IMPACTS).
&&
.MARINE...
ISSUED AT 330 PM EDT THU SEP 3 2015
WINDS AND WAVES WILL REMAIN ON THE LIGHT SIDE TONIGHT AND FRIDAY DUE
TO THE WEAK PRESSURE GRADIENT. LIGHT NORTH WINDS TONIGHT WILL BECOME
ONSHORE FRIDAY. SCATTERED THUNDERSTORMS ARE POSSIBLE THROUGH
SATURDAY.
&&
.HYDROLOGY...
ISSUED AT 1110 AM EDT THU SEP 3 2015
NO IMMEDIATE CONCERNS TO BE AWARE OF TODAY REGARDING RIVER
FLOODING.
HEAVY RAINFALL ASSOCIATED WITH THUNDERSTORM ACTIVITY WILL QUICKLY
PASS THROUGH THE AREA THIS MORNING AND THROUGH EARLY AFTERNOON.
PONDING MAY OCCUR ON ROADWAYS AND LOW LYING AREAS IN AND AROUND
THE HEAVIER RAINFALL. MUCH OF THE HEAVIER ACTIVITY WILL VACATE
THE REGION BY MID AFTERNOON.
THE NEXT 7 DAYS REMAINS ACTIVE AND INCLUDES MULTIPLE CHANCES FOR
RAIN. 7 DAY AREA AVERAGE RAINFALL OF ONE TO TWO INCHES IS POSSIBLE
WITH LOCALLY HIGHER AMOUNTS IN THE VICINITY OF THUNDERSTORMS.
RECENT DRY WEATHER AND LOW RIVER LEVELS...COUPLED WITH THE
PIECEWISE FASHION OF THE RAINFALL...SHOULD ALLOW FOR THE GROUND TO
SOAK UP MUCH OF THE ONSET OF MOISTURE. RUNOFF THEREAFTER IS
LIKELY TO BE HANDLED WELL BY RIVERS...AS THEY HAVE PLENTY OF ROOM
TO TAKE ON ADDITIONAL WATER.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...04
SHORT TERM...04
LONG TERM...OSTUNO
AVIATION...WDM
HYDROLOGY...JAM
MARINE...04
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
744 PM EDT THU SEP 3 2015
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 356 PM EDT THU SEP 3 2015
WV IMAGERY AND RAP ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH ALONG
THE WEST COAST AND A DOWNSTREAM RIDGE FROM TEH SRN PLAINS INTO THE
UPPER MS VALLEY. A SHORTWAVE TROUGH OVER LOWER MI...ON THE FORWARD
FLANK OF THE RIDGE...WAS VERY SLOWLY EDING TO THE SE. AT THE SFC...A
RIDGE EXTENDED FROM QUEBEC AND NRN ONTARIO INTO LAKE SUPERIOR
RESULTING IN LIGHT E TO NE FLOW THROUGH UPPER MI. VIS LOOP SHOWED
MOSTLY SUNNY SKIES ACROSS THE NORTH WITH SCT-BKN CU INLAND CNTRL.
TONIGHT...WITH THE LOSS OF DAYTIME HEATING...THE CU WILL FADE
LEAVING MOSTLY CLEAR SKIES. HOWEVER...SOME MID CLOUS AROUND THD
PERSISTENT LOW MAY MOVE BACK INTO THE SE. GIVEN DEWPOINTS IN LOWER
60S...RADIATIONAL COOLING SHOULD DROP MINS TO AROUND 60...COOLEST
OVER THE INLAND WEST HALF. SO...EXPECT AREAS OF FOG ARE LIKELY TO
DEVELOP...ESPECIALLY CNTRL.
FRI...ALTHOUGH THE LOWER MI MID LEVEL LOW SHOULD STILL
LINGER...UPPER MI WILL REMAIN UNDER THE INFLUENCE OF THE SFC RIDGE
WITH MOSTLY SUNNY SKIES AFTER THE MORNING FOG OR LOW CLOUDS BURN
OFF. WITH 850 MB TEMPS AROUND 15C...TEMPS SHOULD CLIMB TO AROUND
80...WITH LOWER READINGS ALONG THE GREAT LAKES.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 317 PM EDT THU SEP 3 2015
MAINLY FOCUSED ON SHOWER AND THUNDERSTORM COVERAGE/INTENSITY SAT
NIGHT INTO MONDAY AND ON CONTINUED HOT/HUMID CONDITIONS SAT AND SUN.
FRI NIGHT LOOKS DRY FOR MOST PART...BUT THERE IS A SLIGHT CHANCE OF
SHOWERS AND THUNDERSTORMS OVER THE W A SHORTWAVE ENERGY MOVES W OF
THE CWA IN THE SW FLOW ALOFT. A SIMILAR SETUP ON SAT...BUT GREATER
CHANCES OF PRECIP OVER THE W. COULD SEE SOME STRONG TO POSSIBLY
SEVERE STORMS...IF CONVECTION DOES DEVELOP...DUE TO 1000-2000 J/KG
OF MUCAPE. 0-6KM SHEAR WILL BE ON THE WEAK SIDE SAT AT ONLY AROUND
20KTS...WHICH LIMITS ORGANIZED SEVERE POTENTIAL.
THE 12Z/03 GFS IS AN OUTLIER FOR SAT NIGHT IN SHOWING PRECIP OVER
THE CENTRAL CWA. THINK THAT MOST OF THE AREA WILL STAY DRY SAT
NIGHT...WITH THE W POSSIBLY SEEING SOME CONVECTION. PRECIP LOOKS TO
STAY OVER THE W HALF ON SUN AS A STRONGER SHORTWAVE MOVES TO THE W.
WIND SHEAR WILL BE GREATER SUN...WITH 0-6KM BULK VALUES AROUND
30KTS...BUT MUCAPES WILL ONLY BE 1000-1500J/KG. TEMPS WILL BE
WARMEST ON SUN AS 850MB TEMPS WILL BE 20-22C...PROMOTING WARMEST
TEMPS AROUND 90 IN DOWNSLOPING AREAS OF NCENTRAL UPPER MI NEAR LAKE
SUPERIOR.
THE COLD FRONT FROM A LOW PRESSURE SYSTEM MOVING ACROSS SRN CANADA
WILL PASS THROUGH THE AREA SUN NIGHT INTO MON MORNING...WHICH WILL
MEAN LIMITED INSTABILITY AND MINIMAL SEVERE POTENTIAL. COVERAGE OF
CONVECTION LOOKS GOOD...WITH MOST LOCATIONS SEEING SOME PRECIP.
MON WILL SEE CLEARING SKIES AND PRECIP EXITING E. THE AIRMASS WILL
BECOME COOLER AND DRIER...BUT 850MB TEMPS ONLY DROP INTO THE MID
TEENS C BY LATE MON. THIS SHOULD RESULT IN HIGHS FROM THE MID 70S TO
LOW 80S.
LOTS OF UNCERTAINTY MID TO LATE NEXT WEEK AS DETAILS OF A TROUGH
DROPPING INTO THE REGION ARE HARD TO PIN DOWN. DOES LOOK COOLER WITH
AT LEAST A SLIGHT CHANCE OF PRECIP.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 743 PM EDT THU SEP 3 2015
VFR CONDITIONS WILL PREVAIL INTO THE EVENING HOURS AT
KIWD/KCMX/KSAW. SINCE DAYTIME HEATING HAS HELPED MIX OUT SOME OF THE
LOW-LEVEL MOISTURE TODAY AND SINCE WINDS JUST OFF THE SFC WILL BE A
LITTLE STRONGER TONIGHT THAN IN RECENT NIGHTS...FOG SHOULD NOT BE AS
DENSE AS RECENT NIGHTS. IN ADDITION...SINCE MARINE FOG HAS CLEARED
OFF MOST OF LAKE SUPERIOR AND NORTHERN LAKE MICHIGAN...ADVECTION OF
MARINE FOG WON`T BE A CONTRIBUTOR TO POOR CONDITIONS. THUS...AT THIS
POINT...IT APPEARS FOG OVERNIGHT SHOULDN`T DROP VIS BLO MVFR AT
KCMX/KSAW. HOWEVER...NOT OUT OF THE QUESTION THAT THERE COULD BE A
PERIOD OF IFR AROUND DAYBREAK...ESPECIALLY AT KSAW. LIGHT DOWNSLOPE
WIND AT KIWD MAY WORK TO KEEP THAT TERMINAL VFR THRU THE NIGHT. VFR
CONDITIONS ARE EXPECTED AT ALL TERMINALS FROM FRI MID MORNING THRU
THE END OF THE FCST PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 356 PM EDT THU SEP 3 2015
AREAS OF FOG PERSISTED ACROSS THE WESTERN THIRD OF THE LAKE AND IS
EXPECTED TO LINGER INTO FRI WITH NE FLOW CONTINUING.
OTHERWISE...NORTHEAST WINDS OF 10-15KT WILL CONTINUE TODAY WITH 1-3
FT WAVES ACROSS THE WEST. THE NEXT CHANCE FOR WINDS GREATER THAN
20KT WILL BE SUNDAY INTO MONDAY AS THE NEXT SYSTEM APPROACHES FROM
THE WEST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...ROLFSON
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
116 AM EDT WED SEP 2 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 438 PM EDT TUE SEP 1 2015
WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW WSW FLOW INTO THE UPPER
GREAT LAKES. SOME DISTURBANCES ARE NOTED IN THE FLOW...ONE IS IN NE
MN AND THE OTHERS ARE IN SE SD/NE NEBRASKA. DESPITE PRESENCE OF
SHORTWAVE NEARBY AND MLCAPES OF 1500-2500J/KG...NO SHRA OR TSTMS
HAVE DEVELOPED YET THIS AFTN. PER VIS SATELLITE IMAGERY...THERE IS
AN AREA OF WHAT LOOKS LIKE ENHANCED CU DEVELOPMENT FROM MENOMINEE
COUNTY TO ERN MARQUETTE COUNTY AND THEN E TO NRN LUCE COUNTY IN
VCNTY OF LAKE BREEZE OFF LAKE MICHIGAN. TO THE W...SCT
-SHRA/SPRINKLES THAT WERE NEAR/JUST OFFSHORE OF WRN UPPER MI THIS
MORNING HAVE MADE LITTLE EASTWARD PROGRESS AND ARE DIMINISHING IN
COVERAGE. IT`S BEEN ANOTHER UNCOMFORTABLY HOT/HUMID DAY. DWPTS RANGE
FROM THE MID 60S TO LWR 70S WITH TEMPS GENERALLY BTWN 80F AND 90F.
COOLEST CONDITIONS (UPPER 60S/LWR 70S) ARE AT LAKESIDE LOCATIONS
ALONG LAKE MICHIGAN E OF KESC.
WITH THE LACK OF CONVECTION SO FAR THIS AFTN...POTENTIAL FOR
SHRA/TSTM DEVELOPMENT DOESN`T LOOK PROMISING. IF SHRA/TSTMS DO
FORM...IT LOOKS LIKE THE BEST POTENTIAL WILL BE IN THE VCNTY OF THE
LAKE MICHIGAN LAKE BREEZE WHERE CU LOOKS BETTER DEVELOPED ATTM.
RECENT HRRR RUNS POINT TOWARD THAT POSSIBILITY. NOTHING MUCH HIGHER
THAN SCHC POPS WILL UTILIZED INTO THE EARLY EVENING HRS. UPSTREAM
SHORTWAVES OVER SD/NEBRASKA WILL DRIFT NE DURING THE NIGHT...AND
PROBABLY SHOULDN`T POSE A RISK FOR PCPN OVERNIGHT. SOME OF THE DRIER
AIR IN NRN MN WHERE DWPTS HAVE DROPPED OFF AS LOW AS THE UPPER 40S
WILL TRY TO MAKE SOME INROADS INTO UPPER MI DURING THE NIGHT...BUT
GIVEN WEAK LOW-LEVEL WIND FIELDS AND AREAS OF FOG OVER LAKE
SUPERIOR...LITTLE OR NONE OF THIS DRIER AIR SHOULD BE REALIZED HERE.
END RESULT...SHOULD BE ANOTHER NIGHT WITH FOG AND STRATUS
DEVELOPMENT IN MANY AREAS.
IT APPEARS THAT WITH UPSTREAM SHORTWAVES MOVING INTO WI/UPPER MI
WED...THERE SHOULD BE A BETTER POTENTIAL OF SHRA/TSTM DEVELOPMENT.
AS OPPOSED TO THE PCPN POTENTIAL TODAY...MODEL CONSENSUS IS MUCH
BETTER FOR SOME PCPN TO OCCUR ON WED...MAINLY OVER THE INTERIOR W
HALF WHERE INSTABILITY WILL BE GREATER. FOR NOW...OPTED TO RAISE
POPS INTO THE LOW/MID RANGE CHC CATEGORY TOWARD THE WI BORDER. IT
WILL BE A LITTLE COOLER WED...ESPECIALLY NEAR LAKE SUPERIOR WHERE
LAKE BREEZE WILL BE MORE ACTIVE THAN TODAY. DWPTS MIGHT BE A LITTLE
LOWER...BUT CONDITIONS WILL STILL BE UNCOMFORTABLY HUMID.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 351 PM EDT TUE SEP 1 2015
AT 00Z THURSDAY A SHORTWAVE WILL BE SET UP ACROSS UPPER MI AND
WI...RIDING THE N EDGE OF THE LARGER 500MB RIDGE SET UP ACROSS MUCH
OF THE CENTRAL U.S.
AS A RESULT...WILL START OFF WITH SLIGHT CHANCE POPS SLOWLY EXITING
SE WEDNESDAY NIGHT...WITH MAINLY DRY WEATHER THEN FIGURED THURSDAY
THROUGH AT LEAST FRIDAY AS THE 500MB RIDGE BUILDS BACK ACROSS THE
UPPER GREAT LAKES. 80S STILL LOOK ON TRACK FOR TEMPS THROUGH
SATURDAY...IF NOT SUNDAY TOO. THERE WILL BE SLIGHT DIFFERENCES EACH
DAY...BUT MAINLY A BETTER PUSH OF AIR OFF LAKE MI WHERE THEY WILL BE
HELD IN THE 70S.
A LOW EJECTING OUT OF THE PACIFIC NW WILL SWING TO THE S CENTRAL
CANADA AND THE DAKOTAS BY 12Z MONDAY...WITH A BREAKDOWN OF THE UPPER
LEVEL RIDGE OVER THE UPPER GREAT LAKES. BEST CHANCE OF RAIN LOOKS TO
BE LATER SUNDAY NIGHT INTO MONDAY. THE LATEST ECMWF SHOWS ONLY
LIMITED PRECIP REMAINING AS THE SYSTEM MOVES E DURING THE DAY
MONDAY. LOOK FOR TEMPERATURES TO FALL BACK TO NEAR NORMAL FOR HIGHS
MONDAY...AND THEN QUITE A CHANGE FOR TUESDAY WITH HIGHS CURRENTLY
ONLY FCST TO BE IN THE MID TO UPPER 60S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 113 AM EDT WED SEP 2 2015
FOG WILL BE AN ISSUE OVERNIGHT WITH VLIFR CONDITIONS EXPECTED AT ALL
SITES THROUGH SUNRISE. IMPROVEMENT TO VFR WILL OCCUR AROUND MID
MORNING ON WED. KIWD HAS THE BEST CHANCE AT SEEING SOME THUNDER AND
HAVE VCSH AND VCTS TO COVER FOR WED MORNING INTO WED AFTERNOON.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 438 PM EDT TUE SEP 1 2015
SUMMER PATTERN WILL DOMINATE THE UPPER GREAT LAKES THRU THE WEEK
WITH WINDS ON LAKE SUPERIOR UNDER 20KT. FOR MUCH OF THE TIME...
WINDS WILL BE UNDER 15KT. AT SOME POINT OVER THE WEEKEND...LIKELY
LATE IN THE WEEKEND...PRES GRADIENT WILL TIGHTEN AHEAD OF AN
APPROACHING COLD FRONT. THIS WILL LEAD TO AN UPTICK IN WINDS WITH A
BETTER POTENTIAL FOR GUSTS TO REACH THE 20-30KT RANGE. FINALLY...FOG
MAY BE AN ISSUE OVER AT LEAST PORTIONS OF THE LAKE FOR THE NEXT
SEVERAL DAYS UNDER WARM/HUMID AIR MASS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
DENSE FOG ADVISORY UNTIL 8 AM EDT THIS MORNING FOR LMZ248-250.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KF
AVIATION...07
MARINE...ROLFSON
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
933 PM CDT THU SEP 3 2015
.UPDATE...
OVERALL QUIET NIGHT IN STORE AS THERE AS A DRIER AIRMASS IS OVER THE
REGION WITH UPPER RIDGE TO THE W AND LIGHT SOUTHERLY FLOW WITH
OVERALL SFC RIDGE OVER THE AREA. PW`S HAVE FALLEN TO NEAR 1.6 INCHES
WHILE DEEPER MOISTURE NEAR 2 INCHES RESIDES NEAR THE COAST. ONLY LEFT
SOME SLIGHT CHANCE LIGHT RAIN IN CENTRAL MS/DELTA REST OF THIS HOUR
UNTIL 03Z FRIDAY AS THESE ARE GRADUALLY WEAKENING. DRY NIGHT LOOKS
IN STORE AFTERWARDS. LOWS TONIGHT WILL BE COOLER AS DRIER
CONDITIONS LATELY HELPED US REALLY DROP QUICKLY AND COOLER LAST
NIGHT. BLENDED LOWS SLIGHTLY COOLER OVERNIGHT. MAIN FORECAST
CONCERNS WILL BE SOME POTENTIAL FOR SOME FOG/LOW STRATUS IN SE MS
OVERNIGHT AS SOME OF THE COASTAL MOISTURE WILL PUSH TO THE N. SOME
DECOUPLING...DRY CONDITIONS AND MOSTLY CLEAR SKIES WILL HELP IN SOME
POTENTIAL. ADDED PATCHY FOG AS HRRR INDICATES BETTER POTENTIAL
BETWEEN 09-13Z. ADJUSTED SKY GRIDS IN SE MS TO ACCOUNT FOR SOME LOW
STRATUS/FOG. /DC/
.AVIATION...VFR CONDITIONS WILL PREVAIL FOR THE MOST PART THROUGH
FRIDAY...BUT EXPECT A REPEAT OF PATCHY MVFR/IFR FOG IN THE 06-14Z
TIME FRAME GIVEN LITTLE IN THE WAY OF AIRMASS CHANGE DURING THE PAST
24 HRS. ONE THING THAT COULD BE DIFFERENT TONIGHT IS PERHAPS A
GREATER POTENTIAL FOR LIFR STRATUS/FOG IN THE HBG AREA PER RECENT
HRRR GUIDANCE AND INCREASED ONSHORE FLOW CLOSER TO THE COAST.
OTHERWISE...NOT EXPECTING MUCH AFTERNOON SHRA/TSRA COVERAGE FRIDAY
AND HAVE LEFT ANY MENTION OUT OF THE TAFS. /EC/
&&
.PREV DISCUSSION... /ISSUED 320 PM CDT THU SEP 3 2015/
SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT...IN THE WAKE OF LAST
NIGHT`S SHORTWAVE...GREATER HEIGHTS AND A LITTLE DRIER AIR MASS
TODAY HAS LIMITED CONVECTION THIS AFTERNOON DESPITE GREATER
INSOLATION AREAWIDE. THE BLENDED TOTAL PWAT PRODUCT WAS STILL SHOWING
TWO INCH PWATS ACROSS THE SOUTHERN HALF OF OUR CWA AND LOCAL RADARS
SHOWED A FEW ISOLATED SHOWERS AT MID AFTERNOON. ISOLATED SHOWERS AND
A THUNDERSTORM OR TWO WILL REMAIN POSSIBLE OVER OUR SOUTHEAST THROUGH
EARLY EVENING. WATER VAPOR IMAGERY/RAP ANALYSIS THIS AFTERNOON WAS
SHOWING THE CIRCULATION AROUND THE 590DAM RIDGE OVER THE SOUTHERN
PLAINS. THIS RIDGE WILL STRENGTHEN AND SPREAD EAST THROUGH SATURDAY
BECOMING A GREATER INFLUENCE OVER OUR CWA. SURFACE HIGH PRESSURE WILL
REMAIN CENTERED NORTHEAST OF OUR CWA AND REMAIN WEAK THROUGH THE
SHORT TERM. THIS WILL MAINTAIN VERY LIGHT WINDS SURFACE AND
ALOFT...BUT CONTINUE TO PREVENT THE HIGHER DEW POINT AIR OVER
NORTHERN GULF FROM MOVING UP INTO OUR AREA. SO ALTHOUGH AFTERNOON
HIGHS WILL TOP OUT WARMER IN THE MID 90S FRIDAY AND SATURDAY
AFTERNOONS...HEAT INDEX VALUES WILL NOT BE A CONCERN AS MID TO LOWER
6O DEW POINTS MIX DOWN EACH AFTERNOON. IT WILL BE HARD TO RULE OUT AN
ISOLATED SHOWER OR STORM AREAWIDE EACH AFTERNOON BUT THE GREATEST
CHANCE FOR RAIN WILL CONTINUE OVER OUR SOUTHERN ZONES THROUGH THE
WEEKEND. /22/
LONG TERM...SUNDAY THROUGH NEXT WEDNESDAY...UPPER LEVEL PATTERN
WILL BE QUITE AMPLIFIED AT THE BEGINNING OF THE PERIOD WITH
RIDGE...CENTERED OVER TX...EXTENDING WELL NORTHWARD INTO THE GREAT
LAKES REGION. THIS WILL PUT THE CWA IN LIGHT MID/UPPER LEVEL
NORTHERLY FLOW. MEANWHILE AT THE SURFACE...SPRAWLING SURFACE RIDGE
EXTENDING SOUTHWARD FROM THE NE US WILL MAINTAIN LIGHT
NORTHEASTERLY/EASTERLY FLOW KEEPING A RELATIVELY DRY AIRMASS WITH
60S DEWPOINTS ACROSS THE CWA.
MODEL SOUNDINGS NOT INDICATING MUCH IN THE WAY OF AFTERNOON
INSTABILITY EACH DAY AS WARM TEMPS ALOFT KEEP CAPES AND LAPSE RATES
DOWN...BUT STILL ENOUGH AROUND FOR MAINLY ISOLATED TYPE CONVECTION
EACH AFTERNOON/EARLY EVENING. WL CONTINUE TO SEE AFTERNOON MAXES IN
THE LOW TO MID 90S WITH MINS AT NIGHT AROUND 70. /26/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 71 95 72 97 / 8 19 8 18
MERIDIAN 70 94 70 94 / 8 18 8 20
VICKSBURG 70 95 72 97 / 9 19 8 21
HATTIESBURG 71 94 72 94 / 10 26 14 29
NATCHEZ 70 93 72 93 / 10 24 12 29
GREENVILLE 70 96 72 96 / 14 12 8 16
GREENWOOD 69 95 71 95 / 5 10 8 11
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
DC/EC/22/26
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
700 AM CDT WED SEP 2 2015
.SHORT TERM: (THROUGH LATE THIS AFTERNOON)
ISSUED AT 328 AM CDT WED SEP 2 2015
SAME BASIC WEATHER PATTERN REMAINS OVER THE AREA TODAY WITH LARGE
SCALE RIDGING ACROSS THE SOUTHEASTERN 1/3 OF THE CONUS. A SHEAR
AXIS ALOFT STILL STRETCHES FROM EASTERN TEXAS THROUGH ARKANSAS AND
SOUTHEAST MISSOURI INTO THE OHIO VALLEY. A WEAK SHORTWAVE TROF IS
RIDING OVER THE NORTHERN PERIPHERY OF THE RIDGE ACROSS NEBRASKA INTO
IOWA AND IS PRODUCING A BROKEN LINE OF THUNDERSTORMS STRETCHING
ACROSS CENTRAL IOWA INTO NORTHWEST MISSOURI. CURRENT THINKING IS
THAT THESE STORMS WON`T MAKE IT INTO OUR CWFA THIS MORNING BUT
SHOULD WEAKEN AND DISSIPATE AFTER SUNRISE. ANOTHER WARM HUMID DAY
IS EXPECTED WITH HIGHS SIMILAR TO TUESDAY`S...PERHAPS A DEGREE OR
TWO WARMER. SIGNALS FOR AFTERNOON CONVECTION ARE WEAKER IN THE
GUIDANCE THAN THEY WERE FOR YESTERDAY, SO HAVE A DRY FORECAST GOING
THIS MORNING. THAT BEING SAID, I WOULDN`T BE SURPRISED AT ALL IF
SOME ISOLATED THUNDERSTORMS DEVELOPED THIS AFTERNOON.
CARNEY
.LONG TERM: (TONIGHT THROUGH TUESDAY)
ISSUED AT 346 AM CDT WED SEP 2 2015
UPPER LEVEL RIDGE CONTINUES TO CONTROL OUR WEATHER THROUGH THE END
OF THE WEEK INTO THE WEEKEND. THEREFORE IT LOOKS LIKE A PRETTY
STAGNANT WEATHER PATTERN WHICH SHOULD KEEP TEMPERATURES ABOVE NORMAL
WITH LITTLE OR NO CHANCE FOR PRECIP AT LEAST THROUGH SUNDAY OR
MONDAY. MEDIUM RANGE GUIDANCE TRIES TO BEGIN SHIFTING THE PATTERN
MONDAY INTO TUESDAY BY BRINGING THE LONGWAVE TROF OVER THE WEST
COAST ACROSS THE ROCKIES AND UP THROUGH THE NORTHERN PLAINS. THIS
SHOULD AT LEAST PARTIALLY BREAK DOWN THE RIDGE OVER OUR AREA
BRINGING US A CHANCE OF RAIN AND PERHAPS SOME COOLER TEMPERATURES BY
TUESDAY.
CARNEY
&&
.AVIATION: (FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 647 AM CDT WED SEP 2 2015
SHORTWAVE RIDING TOP OF RIDGE CONTINUES TO FUEL BAND OF CONVECTION
FROM CENTRAL IA INTO NW MO, HOWEVER HRRR DATA THROUGHOUT THE
OVERNIGHT HOURS HAS MAINTAINED THE THE GENERAL IDEA THAT THIS
ACTIVITY WILL WEAKEN AND DISSIPATE BEFORE REACHING KCOU OR KUIN.
HIGH CLOUDINESS (AOA 10KFT) ASSOCIATED WITH THIS CONVECTION WILL
OVERSPREAD AREA THIS MORNING, FOLLOWED BY A BIT OF DIURNAL, HI
BASED CU FORMING ONCE AGAIN AROUND MIDDAY.
SPECIFICS FOR KSTL: VFR CONDITIONS ARE EXPECTED, WITH CI WORKING
ACROSS THE AREA THIS MORNING, AND DIURNAL CU WITH BASES AOA 5KFT
THIS AFTERNOON.
TRUETT
&&
.PRELIMINARY POINT TEMPS/POPS:
SAINT LOUIS 94 74 94 75 / 5 5 10 5
QUINCY 92 69 92 70 / 10 5 10 5
COLUMBIA 92 69 93 70 / 10 5 5 0
JEFFERSON CITY 92 69 93 70 / 5 5 5 5
SALEM 92 70 91 70 / 10 5 10 5
FARMINGTON 92 68 92 68 / 10 5 5 0
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
322 PM CDT WED SEP 2 2015
.SYNOPSIS...
ISSUED AT 322 PM CDT WED SEP 2 2015
H5 ANALYSIS THIS MORNING HAD LOW PRESSURE OVER WEST
CENTRAL PORTIONS OF BRITISH COLUMBIA WITH A TROUGH EXTENDING TO THE
SOUTHWEST INTO THE NERN PACIFIC. SOUTH OF THE LOW 50 TO 60 METER HT
FALLS WERE NOTED OVER OREGON AND WASHINGTION STATE WITH A 50 KT JET
STREAK COLLOCATED WITH THE HT FALLS. EAST OF THE LOW...BROAD WEST
SOUTHWESTERLY FLOW EXTENDED ACROSS THE NRN TIER OF STATES AND SRN
CANADA. SOUTH OF THE LOW AND JET STREAK...TWO SHORTWAVES WERE
NOTED...ONE NEAR LAS VEGAS AND A SECOND OFF THE COAST OF SRN
CALIFORNIA. AT THE SURFACE...A TROUGH OF LOW PRESSURE EXTENDED FROM
NORTH CENTRAL NEBRASKA INTO SWRN KS THIS AFTERNOON. WINDS BEHIND
THIS FEATURE WERE FROM THE WEST AT UNDER 10 MPH...WHILE EAST OF THIS
FEATURE...WINDS WERE FROM THE SOUTH AT AROUND 10 MPH. TEMPERATURES
AS OF 3 PM CDT RANGED FROM 95 AT ONEILL...TO 100 AT VALENTINE.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 322 PM CDT WED SEP 2 2015
WEAK UPPER HEIGHT RISES ONGOING ACROSS THE AREA AS CENTRAL PLAINS
RIDGE BUILDS IN RESPONSE TO DEEPING TROUGH ACROSS THE PAC NW. THE
SFC REFLECTION TO THIS IS A WEAK SFC TROUGH ACROSS THE MIDDLE OF THE
WESTERN HALF OF NEB...THOUGH WINDS ARE LIGHT MOST LOCATIONS. MOST
NOTABLE DIFFERENCE ACROSS THE ARE ARE DEW POINT TEMPS WHICH HAVE
DROPPED INTO THE UPPER 40S FROM VTN TO OGA...WITH MID 60S HANGING ON
FROM BBW TO ONL AT THIS HOUR. LOW LEVEL MOISTURE NOT MIXING OUT AS
FAR EAST AS THE NAM SUGGESTED...AND FAR FROM WHAT THE GFS HAD WHICH
IS A KNOWN ISSUE WITH THE GFS. DRY LINE WILL RETREAT WWD AFTER
SUNSET UNDER MAINLY CLEAR SKIES. OPERATIONAL HRRR AND RAP DEVELOPING
A SMALL AREA OF CONVECTIVE PRECIP LATE THIS AFTERNOON AS WEAK
FORCING ALOFT OVERLAYS THE DRY LINE BOUNDARY. SHORT TERM FCST
SOUNDINGS FROM THE HRRR AND RAP SHOW PRONOUNCED INVERTED V PROFILE
WITH VERY LITTLE CAPE ABOVE THE LFC. HAVE NOT INCLUDED MENTION OF
PRECIP NOR QPF THIS EVENING WITH THE IDEA THAT DRY AIR ENTRAINMENT
WILL INHIBIT THE POTENTIAL FOR DEEP...MOIST CONVECTION SUFFICIENT
FOR PRECIP.
AS FLOW BECOMES MORE MERIDIONAL WITH THE DEEPENING UPPER TROUGH IN
THE NW...NEXT PV ANOMALY AND ASSOCIATED PUSH OF MID AND UPPER LEVEL
MOISTURE WILL ROTATE NWD OUT OF THE SWRN UNITED STATES. THIS SHOULD
ALLOW FOR MORE SHOWER AND THUNDERSTORM DEVELOPMENT OVER THE HIGHER
TERRAIN FURTHER WEST WHICH WILL MOVE INTO THE WESTERN PORTIONS OF
THE AREA BY LATE AFTERNOON THURSDAY. SOME LARGE SCALE HEIGHT FALLS
ASSOCIATED WITH THIS FEATURE WILL ALLOW FOR SLIGHT COOLING OF THE
UPPER LEVELS AND WHEN PAIRED WITH SOMEWHAT DEEPER MOISTURE WITH
SERLY SFC WINDS...WILL BE SUFFICIENT FOR POSITIVE CAPE ABOVE THE
LOWER LFC BY LATE IN THE DAY. WEAK SHEAR REMAINS HOWEVER SO ALTHOUGH
BETTER CHANCES EXIST FOR THUNDERSTORMS...LARGE SCALE ORGANIZATION
DOES NOT LOOK FAVORABLE THROUGH 00Z FRI. THE ADDED MID AND UPPER
LEVEL MOISTURE AND ASSOCIATED CLOUDS WITH CONVECTION IN SWRLY
FLOW...WHICH HAS ORIGINS IN THE TROPICS ACCORDING TO ANALYSIS OF
320K MIXING RATIO...WILL ALLOW SLIGHTLY COOLER MAX TEMPS FOR
THURSDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 322 PM CDT WED SEP 2 2015
THURSDAY NIGHT THROUGH SATURDAY NIGHT...IN THE MID RANGE...THE MAIN
FORECASTING CHALLENGES ARE PRECIPITATION CHANCES THURSDAY NIGHT...AND
AGAIN ON FRIDAY NIGHT INTO SATURDAY. FOR THURSDAY
NIGHT...THUNDERSTORMS WILL BE ONGOING ACROSS SWRN NEBR AND NERN
COLORADO AT THE BEGINNING OF THE PERIOD. THIS ACTIVITY WILL MOVE
NORTHEAST INTO THE NIGHTTIME HOURS THANKS TO DECENT MID LEVEL
WAA...WHICH TRACKS FROM SOUTHWESTERN INTO NORTH CENTRAL NEBRASKA. IN
ADDITION...THE NOSE OF A H85 JET STREAK WILL TRACK FROM SOUTH
CENTRAL INTO EASTERN NEBRASKA OVERNIGHT...ADDING ADDTL SUPPORT FOR
PRECIPITATION. AS FOR CHANCES...DECIDED TO KEEP THESE ON THE LOWER
SIDE OF THE ENVELOP AS TIME SECTIONS ARE INDICATIVE OF A DECENT DRY
LAYER BELOW 10000 FT AGL WHICH WILL LIMIT COVERAGE AS WELL AS QPF/S.
ON FRIDAY...STORMS WILL LINGER INTO THE MORNING HOURS ACROSS NERN
PORTIONS OF THE FORECAST AREA. BY AFTERNOON...TRANQUIL WEATHER CONDS
ARE EXPECTED AS THE FORECAST AREA IS IN BETWEEN SYSTEMS. SLIGHTLY
DRIER AIR WILL PUSH INTO THE NORTHWESTERN CWA FRIDAY WITH A DRYLINE
EXTENDING FROM NORTH CENTRAL INTO SWRN NEBRASKA. UPPER LEVEL FORCING
WILL HOLD OFF UNTIL FRIDAY AFTERNOON...SO MOST LOCATIONS WILL SEE A
DRY FCST ON FRIDAY. PCPN CHANCES WILL BEGIN TO INCREASE FRIDAY
EVENING AS A STRONG UPPER LEVEL DISTURBANCE LIFTS ACROSS EASTERN
COLORADO...APPG WESTERN NEBRASKA FRIDAY EVENING. THE BEFORE
MENTIONED DRYLINE WILL RETREAT WEST DURING THE EVENING HRS. HOW FAR
WEST THIS RETREATS AND THE AMOUNT OF DEEP LAYER MOISTURE AVAILABLE
FRIDAY NIGHT IS SOMEWHAT IN DOUBT ATTM. THE GFS IS MUCH DRIER IN THE
WEST COMPARED TO THE NAM SOLN. IN FACT...LAYER PW/S ARE RUNNING
AROUND A HALF AN INCH DRIER IN THE GFS COMPARED TO THE NAM SOLN. NO
SURPRISE...THE GFS IS DRY WITH ITS QPF FIELD FRIDAY NIGHT AND THE
NAM DEVELOPS CONVECTION INVOF THE DRYLINE. INHERITED FCST HAD A
MENTION OF PCPN FRIDAY NIGHT...AND WITH THE GFS BEING TOO DRY IN ITS
LOWER LEVELS UPON INITIALIZATION THIS MORNING...LEANED TOWARD THE
WETTER NAM SOLN WHICH SEEMED TO DO BETTER WITH THE MOISTURE FIELD.
THAT BEING SAID...PRECIPITATION CHANCES IN THE 20 TO 30 PERCENT
RANGE SEEM PLAUSIBLE FOR NOW. THE THREAT FOR PCPN WILL LINGER INTO
SATURDAY IN THE NORTH DURING THE MORNING HOURS...THEN WITH POSSIBLE
DEVELOPMENT OVER EASTERN AND CENTRAL NEBRASKA SATURDAY AFTERNOON. AS
FOR DEVELOPMENT SATURDAY AFTERNOON...ONCE AGAIN...THE GFS SEEMS TOO
DRY WITH ITS MOISTURE FIELD AND CONTINUE TO LEAN TOWARD THE WETTER
NAM SOLN WHICH INITIATES A LINE OF CONVECTION ACROSS THE CENTRAL AND
EASTERN CWA SAT AFTN. DEEP LAYER WIND SHEAR FINALLY REACHES 30 TO 40
KTS SAT AFTN...SO WOULDN/T BE SURPRISED IF A STRONG TO SEVERE STORM
DEVELOPS SAT AFTN/EVE.
SUNDAY THROUGH WEDNESDAY...IN THE EXTENDED...A STRONG UPPER LEVEL
LOW WILL TRACK ACROSS THE NORTHERN ROCKIES INTO SOUTH CENTRAL CANADA
SUNDAY INTO MONDAY. ON SUNDAY...A PREFRONTAL TROUGH WILL PUSH
THROUGH MOST OF THE FORECAST AREA...FORCING LOW LEVEL MOISTURE INTO
CENTRAL AND EASTERN NEBRASKA. FOR THE BULK OF THE FORECAST
AREA...SUNDAY AND SUNDAY NIGHT WILL BE DRY...HOWEVER...LOCATIONS IN
THE FAR NORTHEASTERN CWA WILL SEE A SLIGHT CHANCE FOR RAIN SUNDAY
AFTERNOON/NIGHT. ON SUNDAY NIGHT...A STRONG COLD FRONT WILL PASS
THROUGH THE FORECAST AREA...AND FOR THE MOST PART...WILL BE A DRY
FROPA WITH THE EXCEPTION OF THE FAR EASTERN CWA WHERE SOME LIMITED
MOISTURE WILL REMAIN IN PLACE. THE FRONT WILL THEN STALL ACROSS FAR
SRN NEBRASKA MONDAY...THEN LIFT NORTH MONDAY NIGHT INTO TUESDAY AS A
SECOND UPPER LEVEL WAVE DEVELOPS OVER THE NRN ROCKIES. WITH THE
FRONTAL BOUNDARY DRAPED ACROSS THE FORECAST AREA TUESDAY INTO
WEDNESDAY...WENT AHEAD AND LEFT IN A MENTION OF PCPN. TEMPERATURES
BEHIND THE FRONT MONDAY...TUESDAY AND WEDNESDAY WILL GENERALLY BE IN
THE 70S TO LOWER 80S WHICH IS RIGHT AT SEASONAL FOR EARLY
SEPTEMBER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1224 PM CDT WED SEP 2 2015
VFR CONDITIONS THROUGH THE PERIOD. ONLY CHALLENGE TO THE AVIATION
FORECAST WILL BE WEAK CONVECTION SUGGESTED TO DEVELOP BY SOME
MODELS IN ASSOCIATION WITH THE DRY LINE WHICH MIXES TO A LINE
FROM NEAR ONL SWWD TO NEAR CURTIS IN FRONTIER COUNTY...DEPENDING
ON THE MODEL. FCST SOUNDINGS SUGGEST VERY LITTLE POSITIVE AREA
FOR PARCELS DUE TO WARM TEMPS ALOFT. DRY LINE GRADIENT IN SRN NEB
IS NOT AS TIGHT AS FURTHER NORTH SUGGESTING ONLY WEAK POTENTIAL
FOR UPWARD MOTION ALONG THE BOUNDRY. WITH INVERTED V TYPE SOUNDING
PROFILES FCST BY THE MODELS...WOULD EXPECT A FEW CU/TCU
ORIGINATING AT AROUND 10K FT OR ABOVE BY LATE AFTERNOON ASSOCIATED
WITH THE AFOREMENTIONED BOUNDARY. WILL NOT MENTION ANY PRECIP
HOWEVER BECAUSE DRY AIR ENTRAINMENT SHOULD BE TOO DETRIMENTAL FOR
ANY CONVECTION TO REACH THAT STAGE. SOME OF THE CAMS DO SUGGEST AN
HOUR OR TWO OF REFLECTIVITY ASSOCIATED WITH WEAK CONVECTION...BUT
AS OF NOW THERE IS NOT ENOUGH CONFIDENCE TO MENTION. THIS WILL BE
MONITORED HOWEVER THROUGH THE AFTERNOON AS NEW HIGH RES FCSTS
BECOME AVAILABLE.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CLB
SHORT TERM...JWS
LONG TERM...CLB
AVIATION...JWS
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
849 PM PDT THU SEP 3 2015
.SYNOPSIS...A TROUGH OF LOW PRESSURE ALONG THE CALIFORNIA COAST WILL
MOVE SLOWLY INLAND DURING THE DAY ON FRIDAY AND ACROSS NEVADA ON
SATURDAY. THIS SYSTEM WILL PROVIDE GUSTY SOUTHWEST WINDS ACROSS THE
AREA...PARTICULARLY ACROSS THE SOUTHERN GREAT BASIN. THE SYSTEM WILL
ALSO PROVIDE SOME COOLING WITH TEMPERATURES FALLING BELOW THEIR
SEASONAL NORMS FOR THE WEEKEND.
&&
.UPDATE...AN OUTFLOW BOUNDARY WAS PUSHING ACROSS SOUTHEAST MOHAVE
COUNTY KICKED OFF BY CONVECTION NEAR BAGDAD. PER A REPORT FROM THE
PUBLIC IN WIKIEUP WINDS WERE GUSTING 25-35 MPH AND A FEW SPRINKLES
WERE REPORTED. LIGHTNING DETECTION ALSO SHOWED SOME LIGHTNING IN
THIS AREA. THUS THE GRIDS WERE TWEAKED TO PUT IN A CHANCE FOR
ISOLATED THUNDERSTORMS IN SOUTHEAST MOHAVE COUNTY THROUGH 06Z
FRIDAY. THE HRRR MODEL PUSHED THE OUTFLOW BOUNDARY UP AS FAR AS
KINGMAN BUT DOES NOT BRING ANY CONVECTION THAT FAR NORTHWEST. THE
GRIDS WERE UPDATED TO ADJUST WINDS AND POPS FOR THIS EVENING IN THAT
AREA, OTHERWISE THE FORECAST LOOKS ON TRACK.
&&
.PREVIOUS DISCUSSION...
ISSUED AT 320 PM PDT THU SEP 3 2015
.SHORT TERM...TODAY THROUGH MONDAY MORNING.
RELATIVELY DRY SOUTHWESTERLY FLOW CONTINUES ACROSS THE AREA. WINDS
HAVE PICKED UP MODESTLY THIS AFTERNOON IN MOST LOCATIONS...BUT AS
THE TROUGH OF LOW PRESSURE CURRENTLY LOCATED ALONG THE CALIFORNIA
COAST GRADUALLY MOVES INLAND OVER THE NEXT COUPLE OF DAYS...WINDS
WILL CONTINUE TO INCREASE. MODELS HAVE TRENDED SLIGHTLY STRONGER
WITH WINDS ACROSS MUCH OF THE SOUTHERN GREAT BASIN AND A WIND
ADVISORY HAS BEEN ISSUED FOR ESMERALDA...CENTRAL NYE AND LINCOLN
COUNTIES FOR FRIDAY. WIND GUSTS OF 40 TO 50 MPH ARE EXPECTED...WITH
THE EXCEPTION OF ESMERALDA COUNTY...WHERE WIND GUSTS MAY STRUGGLE TO
REACH 40 MPH. AS THE TROUGH BEGINS TO MOVE THROUGH NEVADA...THE
WINDS WILL SHIFT A BIT FURTHER EAST ON SATURDAY. THE BEST UPPER
LEVEL SUPPORT FOR THE STRONGER WINDS WILL BE LOCATED OVER LINCOLN
COUNTY...NORTHEAST CLARK AND NORTHERN MOHAVE COUNTIES FROM MID
MORNING SATURDAY THROUGH SATURDAY AFTERNOON.
THERE IS SOME POTENTIAL FOR A WEAK DOWNSLOPE WIND EVENT IN THE LEE
OF THE SIERRA ON FRIDAY AFTERNOON JUST AHEAD OF THE TROUGH
PASSAGE...BUT HI RES MODELS ARE INDICATING NOT MUCH MORE THAN 40 MPH
GUSTS AT THIS POINT.
THE TROUGH WILL ALSO PROVIDE SEVERAL DEGREES OF COOLING...BRINGING
TEMPERATURES FROM THEIR SEASONAL NORMS TODAY...DOWN 4 TO 8 DEGREES
FOR FRIDAY...SATURDAY AND SUNDAY...WITH SATURDAY BEING THE COOLEST
OF THE DAYS.
THE LAST ITEM OF NOTE WILL BE ON FRIDAY AFTERNOON ACROSS THE EASTERN
HALF OF MOHAVE COUNTY WHERE...A BRIEF WINDOW OF SOUTHERLY FLOW AHEAD
OF THE TROUGH MAY BE ENOUGH TO PROVIDE ISOLATED SHOWERS OR
THUNDERSTORMS. THE MAIN THREAT WITH ANY STORM WILL BE GUSTY WINDS.
.LONG TERM...MONDAY THROUGH THURSDAY.
THE LATEST OPERATIONAL MODEL GUIDANCE IS IN GOOD AGREEMENT IN THE
LONG TERM PERIOD BEGINNING WITH A BROAD TROUGH ACROSS THE GREAT
BASIN AND MOJAVE DESERT...YIELDING DRIER AIR...BREEZY CONDITIONS AND
SEASONAL TEMPERATURES. THE LATEST GFS SOLUTIONS ARE BEGINNING TO
TREND SOMEWHAT TOWARD THE ECMWF...HOWEVER NOTABLE DIFFERENCES WILL
CONTINUE TO KEEP FORECAST CONFIDENCE ON THE CAUTIOUS SIDE. IT IS
NOTED THAT THE GFS HAS BEEN RATHER AGGRESSIVE IN BRINGING MOISTURE
BACK INTO EASTERN ZONES EARLY NEXT WEEK. WITH WESTERLY FLOW LOOKING
TO DOMINATE THE OVERALL PATTERN INTO NEXT WEEK...IT APPEARS MORE
LIKELY THAT SIGNIFICANT MOISTURE WILL BE EAST OF THE FORECAST AREA.
DECIDED TO LEAN MORE HEAVILY ON THE ECMWF SOLUTION THIS
EVENING...KEEPING THE LONG TERM PERIOD DRY AS A RESULT.
AS FOR THE DIFFERENCES REGARDING THE OVERALL PATTERN...THE GFS AND
ECMWF BOTH DEPICT A SECONDARY OPEN WAVE DIVING DOWN ACROSS THE
NORTHERN GREAT BASIN DURING THE MONDAY-TUESDAY TIMEFRAME...WITH THE
GFS DEPICTING A MORE AMPLIFIED/LESS PROGRESSIVE WAVE. IMPACTS LOOK
TO BE FAIRLY MINIMAL WITH THIS POTENTIAL FEATURE AT THIS TIME...WITH
GUSTY WINDS LOOKING TO BE THE MAIN RESULTANT WEATHER MONDAY-TUESDAY.
BY MID TO LATE WEEK...GUIDANCE HINTS AT THE SUBTROPICAL HIGH
MIGRATING BACK TO THE WEST. THE STRENGTH OF THE HIGH WILL DEPEND ON
IF THERE ARE ANY ADDITIONAL SHORTWAVES DIVING DOWN ACROSS THE
PACIFIC NORTHWEST AND NORTHERN GREAT BASIN. THIS WOULD EFFECTIVELY
KEEP ANY ASSOCIATED RIDGING WITH THE HIGH FAIRLY FLAT AND MITIGATE
THE WARMING OF AFTERNOON HIGHS FOR THE LATTER PART OF THE WEEK. THIS
WILL BE SOMETHING TO KEEP AN EYE ON...AS MODELS CONTINUE TO ATTEMPT
TO CONVERGE ON A COMMON SOLUTION FOR THIS PERIOD IN THE COMING DAYS.
&&
.AVIATION...FOR MCCARRAN...A BROAD LOW PRESSURE SYSTEM NEAR THE
PACIFIC NORTHWEST WILL SLOWLY DROP INTO THE GREAT BASIN THROUGH
SATURDAY. THIS WILL PRODUCE PREVAILING SOUTH TO SOUTHWEST WINDS EACH
DAY THROUGH SATURDAY...WITH GUSTS OF 25-30 KTS IN THE LATE MORNING
AND AFTERNOON HOURS.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...A BROAD LOW PRESSURE SYSTEM NEAR THE PACIFIC NORTHWEST
WILL SLOWLY DROP INTO THE GREAT BASIN THROUGH SATURDAY. SOUTH TO
SOUTHWEST WINDS WITH AFTERNOON AND EVENING GUSTS OF 20-30 KTS ARE
EXPECTED EACH DAY THROUGH SATURDAY. GUSTS NEAR 40 KTS CAN BE
EXPECTED NEAR CENTRAL NEVADA AND FAR NORTHWEST ARIZONA. FEW-SCT
CLOUDS ABOVE 15 KFT MSL CAN BE EXPECTED.
&&
.FIRE WEATHER...CRITICAL FIRE WEATHER CONDITIONS EXPECTED ACROSS NYE
AND ESMERALDA COUNTIES AGAIN ON FRIDAY DUE DRY FUELS...LOW MINIMUM
RELATIVE HUMIDITY VALUES...AND WINDS OF 25-35 MPH WITH GUSTS OF 40
TO 50 MPH. A RED FLAG WARNING REMAINS IN EFFECT THROUGH FRIDAY.
GUSTY CONDITIONS ARE EXPECTED IN THE SPRING AND SHEEP RANGE AND
ACROSS LINCOLN COUNTY ON FRIDAY...MINIMUM RELATIVE HUMIDITY VALUES
MAY DIP BRIEFLY BELOW 15 PERCENT. VERY GUSTY WINDS ARE EXPECTED ON
SATURDAY ACROSS LINCOLN COUNTY...THE HIGHER TERRAIN OF CLARK COUNTY
AND THE NORTHWEST PLATEAU OF ARIZONA...BUT RH VALUES WILL ONLY
BRIEFLY DIP BELOW 15 PERCENT.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
UPDATE...STACHELSKI
SHORT TERM/FIRE WEATHER...CZYZYK
LONG TERM...PULLIN
AVIATION...ADAIR
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1056 PM EDT THU SEP 3 2015
.SYNOPSIS...A VORT MAX WILL AMPLIFY ACROSS CENTRAL NC THROUGH FRI.
MEANWHILE AT THE SURFACE...A BACKDOOR COLD FRONT WILL APPROACH FROM
THE NORTH LATE FRIDAY...THEN PUSH SOUTHWARD THROUGH THE AREA FRIDAY
NIGHT...BEFORE SETTLING TO OUR SOUTH ON SATURDAY. HIGH PRESSURE WILL
NOSE IN FROM THE NORTH OVER THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1050 PM THURSDAY...
EVENING WATER VAPOR IMAGERY DEPICTED AN ELONGATED AXIS OF SHEAR
VORTICITY STRETCHING FROM WESTERN NC NORTHWESTWARD TO A WELL-DEFINED
SHORTWAVE TROUGH OVER WISCONSIN. NWP GUIDANCE INDICATES THE
VORTICITY AXIS WILL BECOME MORE CONCENTRIC WITH TIME AND
SOUTHEASTWARD EXTENT/NEAR THE BASE OF THE PARENT TROUGH AXIS OVER
THE CAROLINAS...ULTIMATELY CULMINATING IN A CLOSED UPPER LOW AND
POCKET OF -9 TO -10 C 500 MB TEMPERATURES OVER CENTRAL NC DURING THE
DAY FRI. THE PRECEDING ASSOCIATED DYNAMIC FORCING FOR ASCENT IS
FORECAST TO SPREAD EAST OF THE APPALACHIANS AND ACROSS CENTRAL VA
AND CENTRAL NC BETWEEN 06-12Z. SHOWERS HAVE BEEN PERCOLATING OVER
WESTERN NC DURING THE PAST COUPLE OF HOURS (AFTER SUNSET/DURING A
TIME THAT SOLELY-DIURNALLY-DRIVEN CONVECTION SHOULD BE DIMINISHING);
AND THIS ACTIVITY IS PRESUMABLY INDICATIVE OF THE INFLUENCE OF THE
AMPLIFYING VORT MAX. THAT FORCING...IN CONJUNCTION WITH LOW LEVEL
CONVERGENCE ALONG A LEE SURFACE TROUGH THAT NEARLY PERFECTLY BISECTS
THE RAH CWFA FROM NNE TO SSW THIS EVENING...MAY YET FOCUS SOME
ISOLATED SHOWERS OVERNIGHT...MAINLY ALONG AND EAST OF THE TROUGH
AXIS/WHERE LOW LEVEL MOISTURE AND ASSOCIATED INSTABILITY FIELDS
ARE/WILL CONTINUE TO BE RELATIVELY MAXIMIZED.
OTHERWISE...SURFACE VISIBILITY IS ALREADY DECREASING ACROSS CENTRAL
NC...AND BOTH STATISTICAL GUIDANCE AND HRRR VISIBILITY FORECASTS
SUGGEST VISIBILITY RESTRICTIONS WILL CONTINUE TO EXPAND AND LOWER IN
A RELATIVELY CALM...CLEAR...AND MOIST (IN THE BOUNDARY LAYER)
ENVIRONMENT OVER CENTRAL NC OVERNIGHT. LOWS AGAIN IN THE UPPER 60S
TO LOWER 70S.
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 325 PM THURSDAY...
OUR BEST SHOT AT SCATTERED TO NUMEROUS SHOWERS AND STORMS WILL BE
LATE FRI INTO FRI NIGHT... WITH SEVERAL FAVORABLE FACTORS IN PLAY.
FIRST... MODELS DEPICT A POCKET OF ABOVE-NORMAL PW SLIDING SOUTHWARD
FROM VA INTO/THROUGH CENTRAL NC TOMORROW... IN CONJUNCTION WITH WEAK
DPVA SPREADING IN FROM THE NW AND NE AND IMPROVING UPPER DIVERGENCE
FROM THE NORTH... ALL AHEAD OF THE INCOMING BACKDOOR COLD FRONT. THE
LARGE-SCALE MODELS INCLUDING THE NAM/GFS/ECMWF/SREF ARE IN AGREEMENT
ON CONVECTION DEVELOPING DURING THE EARLY TO MID AFTERNOON OVER
CENTRAL NC... FOCUSING THE BEST COVERAGE AND HIGHEST AMOUNTS OVER
THE FAR NW PIEDMONT. GIVEN THE EXPECTED MID-UPPER LEVEL DYNAMIC
CONTRIBUTIONS TO ASCENT... DESTABILIZATION WITH GOOD HEATING DURING
THE DAY... AND RISING MOISTURE THROUGH THE COLUMN... CONVECTIVE
COVERAGE LOOKS SUFFICIENT TO RAISE POPS A BIT... TO LIKELY IN THE NW
CWA WITH GOOD CHANCES ELSEWHERE FOR NOW (ALTHOUGH THESE MAY GO UP TO
LIKELY HERE AS WELL IN LATER FORECASTS IF TRENDS HOLD). THE WEAK
DEEP LAYER SHEAR SHOULD LIMIT STORM STRENGTH... ALTHOUGH THE PROFILE
AND DCAPE NOTED ON NAM FORECAST SOUNDINGS WOULD SUGGEST A MARGINAL
WIND THREAT. THE ANTICIPATED SLOW MOVEMENT WITH HIGH WATER CONTENT
WILL BRING A RISK OF SLOW-MOVING STORMS GENERATING URBAN FLOODING.
EXPECT HIGHS OF 90-95 WITH DECENT PREFRONTAL HEATING AND CONTINUED
ABOVE NORMAL THICKNESSES. POPS SHOULD TREND DOWNWARD AFTER NIGHTFALL
WITH LOSS OF INSOLATION... HOWEVER WITH LOW LEVEL CONFLUENT FLOW
NEAR THE BACKDOOR FRONT AND INCREASED ATLANTIC-SOURCE FEED WITH
PERSISTENT UPPER DIVERGENCE OVERNIGHT... WILL KEEP A MENTION OF
SCATTERED SHOWERS AND STORMS THROUGH THE NIGHT... WITH THE BEST
CHANCES WEST. LOWS 67-71. -GIH
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
AS OF 150 PM THURSDAY...
COOLER TEMPERATURES EXPECTED FOR MUCH OF THE LONG TERM AS THE COLD
FRONT THAT IS PROGGED TO COME THROUGH FRIDAY NIGHT WILL BRING A
CHANGE IN AIRMASS FROM THE NORTHEAST. WITH THIS WILL COME A GREATER
FETCH OF MOISTURE FROM OFFSHORE...DRIVEN BY SEVERAL SHORTWAVE
IMPULSES THAT ARE EXPECTED TO MOVE INTO THE STATE DURING THE WEEKEND
AND INTO EARLY NEXT WEEK.
FOR THE WEEKEND...THE GREATEST THREAT FOR RAIN WILL BE IN THE WEST
ON SATURDAY AS THE FRONT MOVES THROUGH AND A CAD-LIKE SCENARIO SETS
UP. AS THE WEEKEND PROGRESSES HOWEVER...AN INVERTED TROUGH ALONG THE
EAST COAST WILL SHARPEN AND THUS BRING A MORE NORTHERLY COMPONENT TO
THE WIND AND SHUT OFFSHORE MOISTURE FEED INTO THE NW PIEDMONT AND
INSTEAD BEGIN TO FOCUS THE BEST CHANCE FOR CONVECTION OVER THE
EASTERN PART OF THE STATE. THUS RAIN CHANCES FOR SUNDAY WILL BE
BETTER IN THE EAST THAN IN THE WEST. THIS PATTERN WILL CONTINUE INTO
LABOR DAY WITH SOUTHEASTERN COUNTIES HAVING THE BEST CHANCE FOR
SHOWERS AND THUNDERSTORMS. HIGHS IN THE LOW TO MID 80S FOR THIS
PERIOD WITH THE POTENTIAL FOR SOME UPPER 70S IN THE NW IF CLOUD
COVER LOCKS IN.
THE BERMUDA HIGH BEGINS TO TAKE BACK OVER FOR MIDWEEK AND THE
SURFACE HIGH OVER OUR AREA AND THE INVERTED TROUGH WILL BEGIN TO
BREAK DOWN. THIS WILL SEE A RETURN TO WARMER TEMPERATURES...ALTHOUGH
GRADUALLY...WITH DIURNAL CHANCES FOR SHOWERS AND ISOLATED
THUNDERSTORMS THROUGH THURSDAY. AT THIS TIME...ANY THUNDERSTORMS
THAT DO OCCUR EITHER THIS WEEKEND OR NEXT WEEK ARE NOT EXPECTED TO
BE SEVERE...BUT A FEW STRONG STORMS CANNOT BE RULED OUT.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
AS OF 810 PM THURSDAY...
THE 24 HR TAF PERIOD...VFR CONDITIONS WILL PERSIST THROUGH THE
EVENING HOURS AND IN MOST LOCATIONS OVERNIGHT. AREAS OF FOG WILL
DEVELOP LATE TONIGHT TOWARD FRIDAY MORNING WITH MAINLY VFR-MVFR
VSBYS WITH THE POTENTIAL FOR IFR/LIFR VSBY/CIG RESTRICTIONS FOR A
SHORT PERIOD TOWARD DAYBREAK AT KRWI AND PERHAPS KFAY. RESTRICTIONS
WILL GRADUALLY IMPROVE AFTER SUNRISE WITH MULTIPLE CLOUD LAYERS
EXPECTED DURING THE DAY FRIDAY. MOST LOCATIONS WILL HAVE BKN MID
LEVEL CLOUDS THROUGHOUT THE DAY WITH A LOWER SCT CLOUD DECK AT 4-
6KFT BECOMING BKN TOWARD MIDDAY AND THE EARLY AFTERNOON. SCATTERED
SHOWERS AND THUNDERSTORMS WILL DEVELOP DURING THE MID TO LATE
AFTERNOON HOURS...FOCUSED ACROSS THE NORTHEAST PIEDMONT AND NORTHERN
COASTAL PLAIN AND THEN SHIFTING TOWARD THE WEST AND SOUTHWEST WITH
LOCALLY REDUCTIONS IN VSBYS AND CEILINGS. MAINLY CALM WINDS ARE
EXPECTED OVERNIGHT WITH A LIGHT NORTH TO NORTHEAST WIND AT LESS THAN
7KTS EXPECTED ON FRIDAY...EXCEPT HIGHER IN THUNDERSTORMS.
LOOKING BEYOND 00Z SATURDAY...SCATTERED SHOWERS AND
THUNDERSTORMS WILL CONTINUE INTO THE EVENING HOURS ON FRIDAY. MORE
WIDELY SCATTERED CONVECTION IS POSSIBLE DURING THE AFTERNOON AND
EVENING ON SATURDAY AND SUNDAY WITH A DECREASE IN COVERAGE AND A
FOCUS TOWARD THE COASTAL PLAIN ON MONDAY AND TUESDAY. LATE NIGHT
AND MORNING FOG AND STRATUS WITH POTENTIALLY SIGNIFICANT
RESTRICTIONS APPEAR PROBABLE ON SATURDAY AND SUNDAY MORNINGS. -BLAES
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...26/HARTFIELD
NEAR TERM...26
SHORT TERM...HARTFIELD
LONG TERM...ELLIS
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
145 PM EDT WED SEP 2 2015
.SYNOPSIS...A DISTURBANCE WILL DROP SOUTHEAST THROUGH THE AREA
TONIGHT THROUGH EARLY THURSDAY...BUT OTHERWISE DEEP HIGH PRESSURE
WILL HOLD OVER THE REGION THROUGH FRIDAY. A COLD FRONT WILL MOVE
SOUTHWARD THROUGH THE AREA LATE FRIDAY INTO SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM WEDNESDAY...
PLENTY OF SUNSHINE THIS MORNING ALTHOUGH IT`S BEING FILTERED
SOMEWHAT BY AREAS OF THIN MID-HIGH CLOUDS BLOWN OFF OF CONVECTION
OVER AND SOUTH OF THE LOWER MISS VALLEY. THE POTENT MID LEVEL WAVE
WE`VE BEEN WATCHING FOR THE LAST FEW DAYS OVER CENTRAL INDIANA IS
NOTED THIS MORNING OVER SE OHIO IS ON TRACK TO DROP SE INTO AND
THROUGH THE AREA LATER TODAY THROUGH TONIGHT. THE TIMING INDICATED
BY THE SPC SSEO / NSSL WRF / 3KM NAM CONUS NEST / NCAR ENSEMBLE
NEIGHBORHOOD PROBABILITIES ARE FAIRLY CLOSE TO THE EXISTING
FORECAST... BRINGING GOOD COVERAGE INTO THE EXTREME NORTHERN CWA
AFTER 19Z OR 20Z... THEN DROPPING TO THE SSE PEAKING IN COVERAGE
AROUND 00Z... THEN MOVING INTO THE SRN/SE CWA WHILE CONTINUING TO
WEAKEN BEFORE DISSIPATING AROUND OR SOON AFTER 06Z. HAVE MADE MINOR
TIMING DIFFERENCES AND HAVE INCREASED INITIAL COVERAGE IN THE 21Z-
03Z TIME FRAME ACROSS THE NORTH. HAVE ALSO ADDED IN LOW CHANCE POPS
IN THE YADKIN VALLEY LATE THIS AFTERNOON AS THE HRRR AND NSSL WRF
DEPICT MOUNTAIN CONVECTION DRIFTING INTO THE SW AND EXTREME WRN CWA
LATE. MODELS CONTINUE TO VARY ON INSTABILITY POTENTIAL WITH THE NAM
(AND IT`S SLIGHTLY HIGHER SURFACE DEWPOINTS) SHOWING MUCAPE VALUES
NEARLY A MAGNITUDE GREATER THAN THE GFS. DEEP LAYER SHEAR REMAINS
MARGINAL AT JUST 20-25 KTS... SO EITHER WAY DON`T EXPECT A GREAT
SEVERE THREAT... ALTHOUGH A FEW STORMS COULD GET STRONG GIVEN THE
DYNAMIC CONTRIBUTION FROM DPVA. THICKNESSES AND HRRR/GRIDDED LAMP/
LOCAL WRF GUIDANCE SUPPORT HIGHS OF 90-94. -GIH
ISOLATED-SCATTERED CONVECTION WILL SLOWLY WANE TONIGHT AS THE LOW
LEVEL AIR MASS UNDERGOES ITS NORMAL NOCTURNAL STABILIZATION. BULK OF
CONVECTION WILL DISSIPATE PRIOR TO 06Z THOUGH POTENTIAL FOR A FEW
SHOWERS TO PERSIST IN THE COASTAL PLAIN UP TO SUNRISE. MIN TEMPS 67-
73. -WSS
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 258 AM WEDNESDAY...
WEAK SUBSIDENCE BEHIND THE DEPARTING DISTURBANCE SHOULD INHIBIT
CONVECTIVE REDEVELOPMENT THURSDAY MORNING. HEATING OF THE AIR MASS
OVER CENTRAL NC SHOULD TRIGGER ISOLATED CONVECTION ABOUT ANYWHERE IN
THE MID-LATE AFTERNOON HOURS. ANOTHER UPPER DISTURBANCE...THOUGH
WEAKER THAN THE SYSTEM EXPECTED TONIGHT...WILL APPROACH FROM THE NW
LATE IN THE DAY AND CROSS CENTRAL NC THURSDAY NIGHT. THIS SYSTEM MAY
PROVIDE ENOUGH LIFT TO INITIATE/SUSTAIN A SHOWER OR TWO BUT FEEL
THAT MOST PLACES WILL REMAIN DRY THURSDAY NIGHT. MAX TEMPS THURSDAY
SHOULD BE COMPARABLE TO DAY...90-95 DEGREES...WITH MIN TEMPS THU
NIGHT 67-72.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 305 AM WEDNESDAY...
FRIDAY THROUGH SATURDAY NIGHT: A BACKDOOR COLD FRONT WILL SINK
SOUTHWARD THROUGH THE AREA ON FRIDAY INTO FRIDAY EVENING AS ANOTHER
WEAK IMPULSE IN THE NORTH-NORTHWEST TO NORTHWESTERLY MID LEVEL FLOW
MOVES ACROSS THE AREA. THIS WILL TRIGGER AT LEAST ISOLATED TO
SCATTERED SHOWERS AND SOME STORMS FRIDAY AFTERNOON INTO THE EVENING.
OVERALL DEEP FLOW CONTINUES TO BE QUITE WEAK. GIVEN THIS AND RATHER
WEAK TO MODEST INSTABILITY EXPECT LITTLE IN THE WAY OF A SEVERE
THREAT... WITH THE ONLY LIMITED THREAT FROM LOCALIZED.... MAINLY
URBAN... FLOODING AS PW/S ARE EXPECTED TO BE AROUND 1.75" OR SO ON
FRIDAY. HIGH TEMPS FRIDAY IN ADVANCE OF THE FRONT ARE EXPECTED TO
REACH INTO THE UPPER 80S TO LOWER 90S. SURFACE HIGH PRESSURE WILL
BUILD INTO THE AREA FROM THE NORTH/NORTHEAST ON FRIDAY NIGHT INTO
SATURDAY. HOWEVER... WE WILL LIKELY SEE SOME LINGERING PRECIP
CHANCES AS A WEAK MID LEVEL LOW DEVELOPS JUST TO THE SOUTH OF THE
AREA. THUS... EXPECT LOW POPS (SLIGHT CHANCE) IN THE NORTHEAST...
WITH THE HIGHEST POPS (CHANCE) IN THE SOUTHWEST. GIVEN NORTHEAST TO
EASTERLY LOW LEVEL FLOW... WE WILL LIKELY START THE DAY WITH A GOOD
BIT OF CLOUD COVER/LOW STRATUS. GIVEN THE COOLER AIR MASS FROM THE
NORTH AND EXPECTED CLOUD COVER... WILL GO WITH HIGHS ON SATURDAY IN
THE LOWER TO MID 80S (AND THIS MAY STILL BE TOO WARM IN SPOTS). LOWS
SATURDAY MORNING ARE EXPECTED TO BE IN THE UPPER 60S AND IN THE MID
TO UPPER 60S SUNDAY MORNING.
SUNDAY THROUGH TUESDAY: THE WEAK MID LEVEL LOW WILL CONTINUE TO
LINGER ACROSS THE SOUTHEAST U.S. DURING THIS TIMEFRAME WHILE SLOWLY
SINKING SOUTHWESTWARD... YET STILL EXTENDING INTO OUR AREA... ALONG
WITH AN INVERTED SURFACE TROUGH NEAR THE COAST TO EASTERN PORTIONS
OF OUR AREA. THIS WILL GENERALLY RESULT IN THE BEST CHANCES FOR
PRECIP TO THE SOUTH OF OUR AREA... BUT WE COULD SEE SOME ISOLATED TO
SCATTERED SHOWERS AND STORMS EACH DAY (MAINLY DIURNAL IN NATURE) AND
GENERALLY ACROSS EASTERN AND SOUTHEASTERN PORTIONS OF CENTRAL NC.
HIGHS WILL REMAIN IN THE 80S... COOLEST ON SUNDAY... WITH LOWS IN
THE 60S.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 145 PM WEDNESDAY...
HIGH CONFIDENCE IN VFR CONDITIONS HOLDING THROUGH MID AFTERNOON
THU... ALTHOUGH THERE WILL BE ONE BRIEF PERIOD OF EXCEPTION. THE
PASSAGE OF AN UPPER LEVEL DISTURBANCE FROM NW TO SE THROUGH THE
REGION LATE TODAY THROUGH THIS EVENING WILL BRING SCATTERED
STORMS... MOST LIKELY TO AFFECT RWI AND PERHAPS RDU... WITH INT/GSO
SEEING A SLIGHTLY LOWER CHANCE OF STORMS AND FAY SEEING THE LEAST
CHANCE. THE PRIMARY WINDOW OF STORM POTENTIAL WILL BE 21Z-01Z AT
INT/GSO/RDU/RWI. A SHORT PERIOD OF GUSTY WINDS AND MVFR TO IFR
CONDITIONS CAN BE EXPECTED IN AND NEAR ANY STORMS... ALTHOUGH
COVERAGE WILL BE SMALL AND DURATION LESS THAN AN HOUR AT ANY GIVEN
LOCATION. OTHERWISE... ANY CIGS ARE LIKELY TO BE ABOVE 6K FT AGL.
LIGHT AND VARIABLE SURFACE WINDS WILL BECOME PREDOMINANTLY FROM THE
NE OR NORTH TONIGHT BUT REMAIN LIGHT THROUGH THU.
LOOKING BEYOND 18Z THU... VFR CONDITIONS LIKELY TO HOLD. THE CHANCE
OF SHOWERS AND STORMS INCREASES LATE FRI INTO FRI NIGHT IN
ASSOCIATION WITH A COLD FRONT PASSAGE... FOLLOWED BY A LOWER CHANCE
SAT AFTERNOON. SUB-VFR LOW CLOUDS AND FOG POSSIBLE LATE FRI NIGHT /
EARLY SAT MORNING... AND AGAIN LATE SAT NIGHT / EARLY SUN MORNING
WITH A LOW LEVEL FLOW FROM THE EAST OR NE BEHIND THE FRONT DRAWING
ATLANTIC MOISTURE INTO THE AREA. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD/WSS
SHORT TERM...WSS
LONG TERM...BSD
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1015 AM EDT WED SEP 2 2015
.SYNOPSIS...A DISTURBANCE WILL DROP SOUTHEAST THROUGH THE AREA
TONIGHT THROUGH EARLY THURSDAY...BUT OTHERWISE DEEP HIGH PRESSURE
WILL HOLD OVER THE REGION THROUGH FRIDAY. A COLD FRONT WILL MOVE
SOUTHWARD THROUGH THE AREA LATE FRIDAY INTO SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM WEDNESDAY...
PLENTY OF SUNSHINE THIS MORNING ALTHOUGH IT`S BEING FILTERED
SOMEWHAT BY AREAS OF THIN MID-HIGH CLOUDS BLOWN OFF OF CONVECTION
OVER AND SOUTH OF THE LOWER MISS VALLEY. THE POTENT MID LEVEL WAVE
WE`VE BEEN WATCHING FOR THE LAST FEW DAYS OVER CENTRAL INDIANA IS
NOTED THIS MORNING OVER SE OHIO IS ON TRACK TO DROP SE INTO AND
THROUGH THE AREA LATER TODAY THROUGH TONIGHT. THE TIMING INDICATED
BY THE SPC SSEO / NSSL WRF / 3KM NAM CONUS NEST / NCAR ENSEMBLE
NEIGHBORHOOD PROBABILITIES ARE FAIRLY CLOSE TO THE EXISTING
FORECAST... BRINGING GOOD COVERAGE INTO THE EXTREME NORTHERN CWA
AFTER 19Z OR 20Z... THEN DROPPING TO THE SSE PEAKING IN COVERAGE
AROUND 00Z... THEN MOVING INTO THE SRN/SE CWA WHILE CONTINUING TO
WEAKEN BEFORE DISSIPATING AROUND OR SOON AFTER 06Z. HAVE MADE MINOR
TIMING DIFFERENCES AND HAVE INCREASED INITIAL COVERAGE IN THE 21Z-
03Z TIME FRAME ACROSS THE NORTH. HAVE ALSO ADDED IN LOW CHANCE POPS
IN THE YADKIN VALLEY LATE THIS AFTERNOON AS THE HRRR AND NSSL WRF
DEPICT MOUNTAIN CONVECTION DRIFTING INTO THE SW AND EXTREME WRN CWA
LATE. MODELS CONTINUE TO VARY ON INSTABILITY POTENTIAL WITH THE NAM
(AND IT`S SLIGHTLY HIGHER SURFACE DEWPOINTS) SHOWING MUCAPE VALUES
NEARLY A MAGNITUDE GREATER THAN THE GFS. DEEP LAYER SHEAR REMAINS
MARGINAL AT JUST 20-25 KTS... SO EITHER WAY DON`T EXPECT A GREAT
SEVERE THREAT... ALTHOUGH A FEW STORMS COULD GET STRONG GIVEN THE
DYNAMIC CONTRIBUTION FROM DPVA. THICKNESSES AND HRRR/GRIDDED LAMP/
LOCAL WRF GUIDANCE SUPPORT HIGHS OF 90-94. -GIH
ISOLATED-SCATTERED CONVECTION WILL SLOWLY WANE TONIGHT AS THE LOW
LEVEL AIR MASS UNDERGOES ITS NORMAL NOCTURNAL STABILIZATION. BULK OF
CONVECTION WILL DISSIPATE PRIOR TO 06Z THOUGH POTENTIAL FOR A FEW
SHOWERS TO PERSIST IN THE COASTAL PLAIN UP TO SUNRISE. MIN TEMPS 67-
73. -WSS
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 258 AM WEDNESDAY...
WEAK SUBSIDENCE BEHIND THE DEPARTING DISTURBANCE SHOULD INHIBIT
CONVECTIVE REDEVELOPMENT THURSDAY MORNING. HEATING OF THE AIR MASS
OVER CENTRAL NC SHOULD TRIGGER ISOLATED CONVECTION ABOUT ANYWHERE IN
THE MID-LATE AFTERNOON HOURS. ANOTHER UPPER DISTURBANCE...THOUGH
WEAKER THAN THE SYSTEM EXPECTED TONIGHT...WILL APPROACH FROM THE NW
LATE IN THE DAY AND CROSS CENTRAL NC THURSDAY NIGHT. THIS SYSTEM MAY
PROVIDE ENOUGH LIFT TO INITIATE/SUSTAIN A SHOWER OR TWO BUT FEEL
THAT MOST PLACES WILL REMAIN DRY THURSDAY NIGHT. MAX TEMPS THURSDAY
SHOULD BE COMPARABLE TO DAY...90-95 DEGREES...WITH MIN TEMPS THU
NIGHT 67-72.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 305 AM WEDNESDAY...
FRIDAY THROUGH SATURDAY NIGHT: A BACKDOOR COLD FRONT WILL SINK
SOUTHWARD THROUGH THE AREA ON FRIDAY INTO FRIDAY EVENING AS ANOTHER
WEAK IMPULSE IN THE NORTH-NORTHWEST TO NORTHWESTERLY MID LEVEL FLOW
MOVES ACROSS THE AREA. THIS WILL TRIGGER AT LEAST ISOLATED TO
SCATTERED SHOWERS AND SOME STORMS FRIDAY AFTERNOON INTO THE EVENING.
OVERALL DEEP FLOW CONTINUES TO BE QUITE WEAK. GIVEN THIS AND RATHER
WEAK TO MODEST INSTABILITY EXPECT LITTLE IN THE WAY OF A SEVERE
THREAT... WITH THE ONLY LIMITED THREAT FROM LOCALIZED.... MAINLY
URBAN... FLOODING AS PW/S ARE EXPECTED TO BE AROUND 1.75" OR SO ON
FRIDAY. HIGH TEMPS FRIDAY IN ADVANCE OF THE FRONT ARE EXPECTED TO
REACH INTO THE UPPER 80S TO LOWER 90S. SURFACE HIGH PRESSURE WILL
BUILD INTO THE AREA FROM THE NORTH/NORTHEAST ON FRIDAY NIGHT INTO
SATURDAY. HOWEVER... WE WILL LIKELY SEE SOME LINGERING PRECIP
CHANCES AS A WEAK MID LEVEL LOW DEVELOPS JUST TO THE SOUTH OF THE
AREA. THUS... EXPECT LOW POPS (SLIGHT CHANCE) IN THE NORTHEAST...
WITH THE HIGHEST POPS (CHANCE) IN THE SOUTHWEST. GIVEN NORTHEAST TO
EASTERLY LOW LEVEL FLOW... WE WILL LIKELY START THE DAY WITH A GOOD
BIT OF CLOUD COVER/LOW STRATUS. GIVEN THE COOLER AIR MASS FROM THE
NORTH AND EXPECTED CLOUD COVER... WILL GO WITH HIGHS ON SATURDAY IN
THE LOWER TO MID 80S (AND THIS MAY STILL BE TOO WARM IN SPOTS). LOWS
SATURDAY MORNING ARE EXPECTED TO BE IN THE UPPER 60S AND IN THE MID
TO UPPER 60S SUNDAY MORNING.
SUNDAY THROUGH TUESDAY: THE WEAK MID LEVEL LOW WILL CONTINUE TO
LINGER ACROSS THE SOUTHEAST U.S. DURING THIS TIMEFRAME WHILE SLOWLY
SINKING SOUTHWESTWARD... YET STILL EXTENDING INTO OUR AREA... ALONG
WITH AN INVERTED SURFACE TROUGH NEAR THE COAST TO EASTERN PORTIONS
OF OUR AREA. THIS WILL GENERALLY RESULT IN THE BEST CHANCES FOR
PRECIP TO THE SOUTH OF OUR AREA... BUT WE COULD SEE SOME ISOLATED TO
SCATTERED SHOWERS AND STORMS EACH DAY (MAINLY DIURNAL IN NATURE) AND
GENERALLY ACROSS EASTERN AND SOUTHEASTERN PORTIONS OF CENTRAL NC.
HIGHS WILL REMAIN IN THE 80S... COOLEST ON SUNDAY... WITH LOWS IN
THE 60S.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 705 AM WEDNESDAY...
THERE IS A HIGH LIKELIHOOD THAT VFR CONDITIONS WILL CONTINUE THROUGH
TONIGHT. THE EXCEPTION WILL BE ISOLATED-SCATTERED CONVECTION WHICH
WILL DEVELOP OR MOVE INTO CENTRAL NC FROM THE NORTH AFTER 18Z. THE
CONVECTION WILL BE SPARKED BY A SEWD MOVING UPPER LEVEL DISTURBANCE
WHICH WILL CROSS OUR REGION EARLY THIS EVENING. CONFIDENCE THAT
CONVECTION WILL OCCUR AT ANY ONE TAF SITES IS FAIRLY LOW BUT WILL
MENTION VICINITY SHOWER IN THE TRIAD TERMINALS THIS AFTERNOON...AND
NEAR KRDU AND KRWI EARLY THIS EVENING.
THE EXTENDED OUTLOOK SUGGEST MAINLY VFR CONDITIONS THOUGH COULD SEE
A BRIEF PERIOD OF EARLY MORNING FOG/STRATUS THURSDAY MORNING AND
FRIDAY MORNING. ALSO...COULD SEE SCATTERED CONVECTION DEVELOP FRIDAY
AFTERNOON INTO FRIDAY NIGHT AHEAD OF A SURFACE BOUNDARY WHICH
PROGRESS SOUTHWARD ACROSS THE AREA. THIS FEATURE MAY CAUSE UNSETTLED
WEATHER TO LINGER INTO SATURDAY WITH IMPROVING AVIATION CONDITIONS
EXPECTED BY SUNDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD/WSS
SHORT TERM...WSS
LONG TERM...BSD
AVIATION...WSS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
451 PM CDT WED SEP 2 2015
.UPDATE...
ISSUED AT 441 PM CDT WED SEP 2 2015
WILL NEED TO DO A FORECAST UPDATE TO ACCOUNT FOR SHOWERS MOVING
FROM THE MILES CITY TO GLENDIVE AREA OF MONTANA TOWARD THE NORTH
DAKOTA BORDER. THE HRRR IS HANDLING THE PRECIPITATION THE BEST AS
COMPARED TO OTHER HI RES SHORT TERM MODELS. THE HRRR HAS THE
SHOWERS DEPICTED...AND BRINGS THEM INTO NORTH DAKOTA...EVEN INTO
THE CENTRAL PART OF THE STATE LATER.
KMLS ASOS HAD A WIND GUST OF 52 KNOTS...60 MPH...HOWEVER...THE
STATION REPORTED NO THUNDER AND THE LIGHTNING NETWORK SHOWED NO
LIGHTNING. SO...IT WAS A SHOWER THAT MIXED DOWN HIGHER WIND AND
LIKELY EVAPORATION ADDED TO THE DOWNWARD TRANSPORT. DOWNDRAFT CAPE
IS ANALYZED 1700-1800 UNITS ACROSS WESTERN NORTH DAKOTA.
WILL ADD POPS TO THE WEST AND MAY NEED TO BRING THEM INTO THE
CENTRAL PART OF THE STATE ON A LATER UPDATE. WILL THE ACTIVITY
HOLD TOGETHER AS DEPICTED BY THE HRRR...IS THE QUESTION.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 330 PM CDT WED SEP 2 2015
MAIN CONCERNS THIS PERIOD WILL BE SOME PATCHY FOG TONIGHT...
AND TEMPERATURES AND SOME SLIGHT CHANCES FOR THUNDERSTORMS ALONG
A SLOWLY MOVING FRONTAL BOUNDARY ACROSS THE NORTHWEST ON THURSDAY.
TONIGHT...THE H500 FLOW REMAINS ORIENTED SOUTHWEST TO NORTHEAST.
EXPECT THE COLD FRONTAL BOUNDARY WHICH IS ALIGNED WITH THE FLOW
ALOFT TO ONLY MOVE SLOWLY EAST TONIGHT AND THURSDAY. THIS WILL
GIVE THE REGION ANOTHER OPPORTUNITY FOR VERY WARM TEMPERATURES
THURSDAY ALONG AND AHEAD OF THE FRONT. HIGHS CENTRAL SECTIONS WILL
BE CLOSE TO 100. RELATIVELY COOLER AIR...ALTHOUGH STILL IN THE
MID 80S...WILL MOVE INTO THE NORTHWEST. LOW LEVEL MOISTURE
POOLING ALONG THE JAMES RIVER VALLEY TONIGHT WILL FAVOR MUGGY
CONDITIONS AND SOME PATCHY FOG TONIGHT WITH DEWPOINTS AROUND 70.
ON THURSDAY THE HEAT INDEX VALUES WILL RISE TO NEAR 100 ACROSS THE
JAMES RIVER VALLEY BY AFTERNOON.
THE NAM/GFS BOTH DEVELOP SOME WEAK CONVECTION ALONG THE FRONTAL
BOUNDARY THURSDAY. THE WRF MODEL DOES TOO BUT IN THE AFTERNOON.
WILL ADD ISOLATED THUNDERSTORMS FAR WEST INTO THE NORTH CENTRAL
THURSDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 330 PM CDT WED SEP 2 2015
A SIGNIFICANT PATTERN CHANGE WILL IMPACT THE NORTHERN PLAINS FOR
THE UPCOMING HOLIDAY WEEKEND...WITH COOLER AND WETTER CONDITIONS.
STRONG UPPER LEVEL LOW DROPPING INTO THE PACIFIC NORTHWEST TODAY
WILL BECOME AN OPEN WAVE AND DEEPEN OVER THE WEST COAST THROUGH
SATURDAY. BY THURSDAY NIGHT EMBEDDED S/WV IMPULSES WILL BEGIN TO
APPROACH THE REGION...AND WHEN COUPLED WITH A SLOW MOVING SFC
BOUNDARY WILL RESULT IN CHANCES FOR SHOWERS/THUNDERSTORMS WEST TO
EAST DURING THE NIGHT. A PARTICULARLY STRONG EMBEDDED WAVE WILL
LIFT NORTHEAST ACROSS THE DAKOTAS LATE THURSDAY NIGHT/FRIDAY
MORNING AND MAY BRING MODERATE TO HEAVY RAIN TO PORTIONS OF NORTH
CENTRAL AND EASTERN NORTH DAKOTA DURING THAT TIMEFRAME.
FRIDAY-SATURDAY THE WEST COAST UPPER TROUGH BEGINS TO MOVE FARTHER
INLAND AND WILL DIRECT A SERIES OF SHORTWAVE ENERGY IMPULSES ACROSS
THE NORTHERN PLAINS. THE EXPECTED INCREASE IN CLOUD COVER AND CAA
IN THE WAKE OF THE SFC FRONT WILL RESULT IN MUCH COOLER
TEMPERATURES...WITH HIGHS DROPPING INTO THE 70S MOST AREAS BY
SATURDAY. SATURDAY NIGHT INTO SUNDAY THE BASE OF THE UPPER TROUGH
LIFTS NORTHEASTWARD ACROSS THE ROCKIES AND INTO THE NORTHERN
PLAINS...REACHING FAR SOUTH CENTRAL CANADA SUNDAY NIGHT. THIS
TIME PERIOD (FRIDAY-SUNDAY) WILL SEE VERY GOOD CHANCES FOR SHOWERS
AND THUNDERSTORMS. HEAVIEST PRECIPITATION FORECAST ACROSS THE
NORTH. TOTAL RAINFALL THURSDAY NIGHT THROUGH SUNDAY IS FORECAST TO
RANGE FROM AROUND HALF AN INCH SOUTHWEST...TO NEAR 2 INCHES NORTH.
HEAVIER AMOUNTS VERY POSSIBLE WITH THUNDERSTORMS. INSTABILITY NOT
OVERLY IMPRESSIVE SO WHILE A FEW STRONGER STORMS MAY FORM...THE
OVERALL SEVERE THREAT WILL BE MINIMAL.
MUCH COOLER IN THE WAKE OF THE STORM SYSTEM MONDAY...WITH FORECAST
HIGHS MID 60S TO LOW 70S. A QUASI-ACTIVE UPPER LEVEL ZONAL FLOW
SETS UP EARLY TO MID NEXT. THIS IS A DEVIATION FROM PREVIOUS
MODELS SO UNCERTAINTY RATHER HIGH AT THIS POINT. STILL LOOKS LIKE
A SLOW MODERATION IN TEMPERATURES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 330 PM CDT WED SEP 2 2015
AT 3 PM CDT...LOW PRESSURE ACROSS MONTANA WAS BRINGING SOUTHERLY
FLOW INTO THE REGION. VFR CONDITIONS ARE EXPECTED THROUGH THE TAF
PERIOD. SOME PATCHY FOG IS POSSIBLE IN THE JAMES RIVER VALLEY
THURSDAY MORNING. AT THIS TIME KEPT VSBYS AT 5 MILES OR GREATER
KBIS-KJMS AFTER 12Z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JPM
SHORT TERM...WAA
LONG TERM...NH
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1218 AM CDT WED SEP 2 2015
.UPDATE...
ISSUED AT 1218 AM CDT WED SEP 2 2015
NO CHANGES MADE...FORECAST IS ON TRACK.
UPDATE ISSUED AT 939 PM CDT TUE SEP 1 2015
THE 22-01 UTC HRRR ITERATIONS CONTINUE TO EXPAND THE COVERAGE OF
FOG TO MOST LOCATIONS ALONG AND EAST OF US HIGHWAY 85 LATE TONIGHT
INTO WEDNESDAY MORNING AS 60S F DEWPOINTS CONTINUE TO ADVECT
NORTH-NORTHWEST THIS EVENING. CERTAINLY CANNOT RULE OUT A
POTENTIAL DENSE FOG ADVISORY LATER TONIGHT GIVEN THE SIGNAL IN THE
HRRR.
UPDATE ISSUED AT 554 PM CDT TUE SEP 1 2015
DID ADD A MENTION OF FOG TO MUCH OF CENTRAL NORTH DAKOTA TONIGHT
AS 60S F DEWPOINTS CONTINUE TO ADVECT NORTH EARLY THIS
EVENING...WITH LIGHT WINDS AND CLEAR SKIES THROUGH THE OVERNIGHT.
THE 21 UTC HRRR AND 18 UTC NAM NEST SUPPORT THIS POTENTIAL VIA
THEIR REDUCED VISIBILITY FORECASTS ACROSS CENTRAL NORTH DAKOTA
LATE TONIGHT INTO EARLY WEDNESDAY MORNING.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 310 PM CDT TUE SEP 1 2015
THIS AFTERNOON...A WEAK SURFACE LOW PRESSURE TROUGH AND
ASSOCIATED WARM FRONT OVER CENTRAL SOUTH DAKOTA WAS A REFLECTION
OF A WEAKENING SHORT WAVE TROUGH ALOFT. THIS FEATURE IS FORECAST
TO MEANDER NORTHEAST WHILE DIMINISHING WITH TIME. SOUTHERLY LOW
LEVEL FLOW OVER THE WARM FRONT WILL TRANSFER MOISTURE NORTH INTO
THE JAMES RIVER VALLEY WHERE SEVERAL HIGH RESOLUTION MODELS AS
WELL AS THE GFS/NAM FORECAST SOME CONVECTION OVERNIGHT. WILL NEED
SOME TIME TO DEVELOP THIS SCENARIO SO DELAYED THE ONSET OF
CONVECTION UNTIL MIDNIGHT. OTHERWISE THIS FORCING WILL END/SHIFT
TO THE EAST ON WEDNESDAY. SKIES WILL BE MOSTLY SUNNY WEDNESDAY.
WITH A BROAD THERMAL RIDGE OVER EASTERN MONTANA AND NORTH DAKOTA
HIGHS WILL WARM WELL INTO THE 90S. HUMIDITY WILL BE LOW WITH
AFTERNOON VALUES REACHING 15 PERCENT WEST. THE MAJOR MISSING
COMPONENT WAS WINDS FOR FIRE WEATHER CONCERNS. WINDS WILL REMAIN
BELOW 15 MPH FOR THE MOST PART WEDNESDAY AFTERNOON.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 310 PM CDT TUE SEP 1 2015
CONTINUED VERY WARM WEDNESDAY INTO THURSDAY...FOLLOWED BY A
SIGNIFICANT PATTERN CHANGE FOR THE UPCOMING HOLIDAY WEEKEND.
STRONG UPPER LEVEL LOW DROPPING INTO THE PACIFIC NORTHWEST
WEDNESDAY WILL BECOME AN OPEN WAVE AND DEEPEN OVER THE WEST COAST
THROUGH SATURDAY. DURING THIS TIME NORTH DAKOTA WILL REMAIN ON THE
WESTERN EDGE OF THE UPSTREAM RIDGE AXIS...KEEPING VERY WARM AND
DRY AIR OVER THE STATE. HIGHS THURSDAY WILL ONCE AGAIN REACH INTO
THE 90S MANY LOCATIONS...WITH 80S NORTHWEST IN THE WAKE OF A SLOW
MOVING FRONTAL BOUNDARY. BY THURSDAY NIGHT EMBEDDED S/WV IMPULSES
WILL APPROACH THE REGION...AND WHEN COUPLED WITH THE BOUNDARY WILL
RESULT IN CHANCES FOR SHOWERS/THUNDERSTORMS WEST TO EAST DURING
THE NIGHT.
FRIDAY-SATURDAY THE WEST COAST UPPER TROUGH BEGINS TO MOVE FARTHER
INLAND AND WILL DIRECT A SERIES OF SHORTWAVE ENERGY IMPULSES ACROSS
THE NORTHERN PLAINS. THE EXPECTED INCREASE IN CLOUD COVER AND CAA
IN THE WAKE OF THE SFC FRONT WILL RESULT IN MUCH COOLER
TEMPERATURES...WITH HIGHS DROPPING INTO THE MID 60S NORTHWEST TO
LOW 80S OVER THE SOUTHERN JAMES RIVER VALLEY BY SATURDAY. SATURDAY
NIGHT INTO SUNDAY THE BASE OF THE TROUGH LIFTS NORTHEASTWARD INTO
THE NORTHERN PLAINS...REACHING SOUTHERN CANADA BY SUNDAY NIGHT.
THIS TIME PERIOD (FRIDAY-SUNDAY) WILL SEE VERY GOOD CHANCES FOR
SHOWERS AND THUNDERSTORMS.
A MORE ZONAL FLOW SETS UP EARLY NEXT WEEK AND SHOULD RESULT IN
MAINLY DRY CONDITIONS AND SOME TEMPERATURE RECOVERY AS WE PROGRESS
INTO THE MIDDLE PORTIONS OF THE WORK WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1218 AM CDT WED SEP 2 2015
AREAS OF FOG ARE IN THE FORECAST ACROSS MOST OF WESTERN AND
CENTRAL NORTH DAKOTA THIS MORNING. KJMS AND KBIS ARE MOST LIKELY
TO BE IMPACTED...WITH IFR/LIFR VISIBILITY POSSIBLE. KMOT AND KDIK
MAY BE ON THE FRINGE OF THE POTENTIAL FOG BANK. ONCE THE FOG BURNS
OFF THROUGH THE MORNING...VFR CONDITIONS ARE EXPECTED.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AC
SHORT TERM...WAA
LONG TERM...NH
AVIATION...AC
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1141 PM CDT TUE SEP 1 2015
.UPDATE...
ISSUED AT 1136 PM CDT TUE SEP 1 2015
OTHER THAN A PATCH OF MID LEVEL CLOUDS OVER THE CENTRAL DAKOTAS NO
INDICATIONS YET OF ANY CONVECTIVE DEVELOPMENT. LOW LEVEL JET
REMAINS FOCUSED ON SW MN WHERE ONGOING DEEP CONVECTION EXISTS.
WILL MAINTAIN LOW POPS AS WEAKER JET DEVELOPING OVER S CENTRAL ND.
NO CHANGES TO CURRENT FORECAST.
UPDATE ISSUED AT 941 PM CDT TUE SEP 1 2015
THUNDER CHANCES STILL THE CHALLENGE TONIGHT. THE HRRR WHICH WAS
OVERLY AGGRESSIVE IN DEVELOPING STORMS OVER OUR WESTERN FA HAS NOW
BACKED OFF AND FOCUSING DEVELOPMENT OVER SW MN WHERE THE MORE
PROMINENT LOW LEVEL JET IS TAKING SHAPE. A FEW OF THE SHORT RANGE
MODELS CONTINUE WITH SOME MODEST DEVELOPMENT LATER TONIGHT SO WILL
KEEP SLIGHT CHANCES GOING AS NOCTURNAL DEVELOPMENT SOMETIMES
FICKLE. BEST LOW LEVEL MOISTURE FLUX IS OVER THE WESTERN FA SO
HAVE ADDED SOME PATCHY FOG TO THIS AREA AS A START.
UPDATE ISSUED AT 645 PM CDT TUE SEP 1 2015
NO CHANGES NEEDED THIS UPDATE PERIOD.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 325 PM CDT TUE SEP 1 2015
500 MB SHORT WAVE NOTED IN SOUTHEASTERN SOUTH DAKOTA MOVING
NORTHEAST. A BAND OF SHOWERS ARE WITH THIS SYSTEM. FOR TONIGHT
QUESTION IS PRECIP CHANCES OVERNIGHT INTO WED MORNING MAINLY FOR
NE ND INTO NW MN. FOR THE PAST COUPLE OF DAYS MODELS HAVE
INDICATED THREAT FOR SOME CONVECTION TO DEVELOP NR 06Z IN THE MID
RRV AND THE MOVE NORTHEAST THROUGH LAKE OF THE WOODS REGION BY
12Z. 12Z MODELS TODAY SHOW TO SOME DEGREE THE SAME THING...BUT
MORE GFS IN THIS CASE AS MOST SHORT RANGE MODELS SUCH AS THE HRRR
AND RAP DONT SHOW (AT LEAST WITH MIDDAY AND EARLY AFTN RUNS).
THERE IS AN IMPRESSIVE LOW-850 MB MOISTURE RETURN THIS EVENING-
OVERNIGHT. SEEING 70 DEW PTS ALONG THE SD/ND BORDER INTO THE
ALEXANDRIA AREA WHILE MOST OF OUR FCST AREA HAS DEW PTS IN THE
50S. SO WILL SEE A MOISTURE SURGE TONIGHT AND INSTABILITY INCREASE
IN THE 850 MB LAYER 06Z-12Z PERIOD WHEN A FEW HUNDRED 850 MB CAPE
AVAILABLE. PROBLEM IS LOW LEVEL JET IS VERY WEAK 20 KTS MAYBE. BUT
WILL SIDE WITH CONSISTENCY AND KEEP LOW POPS IN BUT HAVE THEM
06Z-12Z....EXTENDING THEM A FEW HOURS PAST 12Z IN LAKE OF THE
WOODS. WEDNESDAY WILL BE MUCH MORE HUMID AND WARM.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 325 PM CDT TUE SEP 1 2015
HOT AND HUMID ON THURSDAY WITH MID 80S EAST TO LOW 90S WEST. WILL
MAINTAIN A LOW THREAT FOR PRECIP LATE THURSDAY NIGHT IN ERN
ND...THEN KEEP CHC POPS ON FRIDAY. UNCERTAIN HOW EVENT WILL PLAY
OUT BUT WILL HAVE SEVERAL SHORT WAVES AND SFC LOWS MOVE NORTHEAST
ALONG A FRONTAL BOUNDARY WHICH WILL BE OVER OR NEAR OUR AREA. EACH
ONE GIVING GOOD CHANCES FOR SHOWERS AND THUNDERSTORMS STARTING
LATE FRIDAY. DAY TO DAY TIMING OF COURSE IS DIFFICULT AT THIS
STAGE.
SATURDAY TO TUESDAY...MODELS IN GOOD AGREEMENT WITH THE GENERAL
500MB SOUTHWEST FLOW ALOFT AND EVOLUTION WITH A CLOSED STRONG SHORT
WAVE MOVING OVER THE NORTHERN PLAINS EARLY NEXT WEEK. AS A RESULT AN
ACTIVE WEATHER PATTERN WITH SEVERAL ROUNDS OF CONVECTIVE ACTIVITY
CAN BE EXPECTED FOR THE REGION OVER THE HOLIDAY WEEKEND.
UNCERTAINTIES EXIST WITH THE TIMING AND PLACEMENT OF THE LEAD WAVE
AND THE STRONGER SHORT WAVE ON MONDAY. CURRENTLY A LEAD WAVE IS
EXPECTED TO BRING A ROUND OF THUNDERSTORMS FRIDAY NIGHT WITH ANOTHER
ROUND SATURDAY NIGHT BEFORE THE THE LIGHTER WRAP AROUND PCPN ON
SUNDAY AFTN AND EARLY MONDAY. GIVEN THE AMPLE MOISTURE IN
PLACE...PWATS APPROACHING 2 INCHES...HEAVY RAIN WILL BE POSSIBLE
WITH ANY STORM. TEMPERATURES WILL BE WARMEST ON SATURDAY WITH LOW
80S IN THE SE HALF OF THE FA AND 70S IN THE NW...HIGHLY INFLUENCED
BY EXPECTED CLOUD COVER. A COOLER...CLOSER TO AVERAGE TEMP REGIME IS
EXPECTED WITH 70S SUNDAY TO TUE BEHIND DEPARTING SHORT WAVE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1136 PM CDT TUE SEP 1 2015
CONVECTIVE DEVELOPMENT OVERNIGHT REMAINS TOO UNCERTAIN TO MENTION
IN ANY TAFS. DID MENTION SOME BR DEVELOPMENT TOWARDS MORNING AS
LOW LEVEL MOIST AIR CONTINUES TO SPREAD NORTHWARD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...RIDDLE
LONG TERM...JK/RIDDLE
AVIATION...VOELKER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
232 AM EDT WED SEP 2 2015
.SYNOPSIS...
ABOVE NORMAL TEMPERATURES FOR EARLY SEPTEMBER WILL CONTINUE INTO
NEXT WEEK WITH GRADUALLY DECREASING HUMIDITY LEVELS. OPPORTUNITIES
FOR RAINFALL WILL REMAIN LIMITED AS HIGH PRESSURE AT THE SURFACE
AND ALOFT DOMINATES THE REGIONAL WEATHER PATTERN.
&&
.NEAR TERM /UNTIL 10 AM THIS MORNING/...
EXPECT FOG TO EXPAND THROUGH THE PREDAWN HOURS AND MAY BE LOCALLY
DENSE IN SPOTS WITH VISIBILITY AOB 1/2SM. UPPER LEVEL DISTURBANCE
MOVG INTO WV MAY KICK OFF A VERY ISOLD SHOWER INVOF THE LAURELS AS
PER HRRR BUT CONFIDENCE AND POPS ARE QUITE LOW. BETTER CHC LATER
TODAY WITH THE HEATING CYCLE.
&&
.SHORT TERM /10 AM THIS MORNING THROUGH 6 PM THURSDAY/...
RIDGING STAYS IN PLACE TODAY. THERE IS A TINY DEPRESSION IN THE
OTHERWISE MASSIVE UPPER LEVEL RIDGE. THE DEPRESSION IS CURRENTLY
ASSOCD WITH A CLUSTER OF STORMS OVER CENTRAL IN. THIS DEPRESSION
SHOULD MOVE EASTWARD THRU THE UPPER OHIO VALLEY AND INTO THE MID
ATLANTIC.
BUT THAT FEATURE MAKES ONLY A SMALL DIP IN MID-LVL TEMPS AND TINY
DECREASE IN STABILITY ON WED. THIS MAY BE ENOUGH TO ALLOW SCT
SHRA/TSRA TO DEVELOP IN THE AFTN OVER THE HIGHER TERRAIN...MAINLY
THE LAURELS AND NRN MTNS. THE 30-40 POPS IN THE MTNS WILL PROBABLY
BE THE HIGHEST POPS WE DRAW FOR QUITE A FEW DAYS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
AN ANOMALOUS UPPER LEVEL RIDGE IS FORECAST TO DOMINATE THE LARGE
SCALE PATTERN OVER THE NORTHEASTERN CONUS INTO EARLY NEXT
WEEK...WITH HIGH PRESSURE TAKING CONTROL AT THE SFC. THIS PATTERN
WILL CONTINUE TO SUPPORT ABOVE-NORMAL TEMPERATURES AND VERY
LIMITED TO NO RAINFALL ACROSS CENTRAL PA THROUGH THE LABOR DAY
WEEKEND.
THE GFS REMAINS MORE BULLISH VS. THE ECMWF WITH CONVECTION ON
FRIDAY. HIGH PRESSURE INITIALLY CENTERED OVER QUEBEC WILL DROP SWD
OVER THE WEEKEND AND BRING SLIGHTLY COOLER AND DRIER/LESS HUMID AIR
INTO THE REGION. NO RISK OF RAIN AGAIN UNTIL PROBABLY NEXT
TUESDAY AS A COLD FRONT APPROACHES FROM THE GREAT LAKES/OH VLY.
&&
.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
OVERNIGHT CONDITIONS WILL VARY. WHILE THERE HAS BEEN IFR FOG ALREADY
AT BRADFORD...IT HAS NOW SUNKEN INTO THE VALLEY. GIVEN THE LIGHT
WINDS AND LOW DEWPOINT DEPRESSIONS EXPECT VARIED IFR OR LOWER
VSBYS AND CIGS AT BFD THROUGH 13Z. AFTER CONDITIONS SHOULD IMPROVE
WITH VFR BY 14Z.
ELSEWHERE A HAZY WARM AND HUMID LATE SUMMER EVENING IS IN
PROGRESS. THE VFR CONDITIONS HAVE BEGUN TO GIVE WAY TO
RESTRICTIONS WITH IFR AT UNV AND MVFR AT AOO. THERE SHORT RANGE
MODELS ARE SHOWING A SLIGHT DRIER AIR MASS IN THE BOUNDARY
LAYER...WHICH COULD LIMIT OVERALL FOG POTENTIAL. HOWEVER IT
REMAINS EXPECTED THAT THE OVERNIGHT TO EARLY MORNING HOURS WILL
GIVE WAY TO DEVELOPING RESTRICTIONS AS PATCHY VALLEY FOG FORMS
ONCE AGAIN. THESE CONDITIONS SHOULD CONTINUE THROUGH 14Z...BEFORE
IMPROVING.
MORE CLEAR NIGHTS WITH AM VALLEY FOG AND MOSTLY SUNNY DAYS ARE
EXPECTED FOR THE NEXT SEVERAL DAYS.
OUTLOOK...
THU-SUN...PATCHY AM FOG POSS...MAINLY KIPT/KBFD. OTHERWISE VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...DANGELO
LONG TERM...RXR
AVIATION...LA CORTE/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
209 AM EDT WED SEP 2 2015
.SYNOPSIS...
ABOVE NORMAL TEMPERATURES FOR EARLY SEPTEMBER WILL CONTINUE INTO
NEXT WEEK WITH GRADUALLY DECREASING HUMIDITY LEVELS. OPPORTUNITIES
FOR RAINFALL WILL REMAIN LIMITED AS HIGH PRESSURE AT THE SURFACE
AND ALOFT DOMINATES THE REGIONAL WEATHER PATTERN.
&&
.NEAR TERM /UNTIL 10 AM THIS MORNING/...
EXPECT FOG TO EXPAND THROUGH THE PREDAWN HOURS AND MAY BE LOCALLY
DENSE IN SPOTS WITH VISIBILITY AOB 1/2SM. UPPER LEVEL DISTURBANCE
MOVG INTO WV MAY KICK OFF A VERY ISOLD SHOWER INVOF THE LAURELS AS
PER HRRR BUT CONFIDENCE AND POPS ARE QUITE LOW. BETTER CHC LATER
TODAY WITH THE HEATING CYCLE.
&&
.SHORT TERM /10 AM THIS MORNING THROUGH 6 PM THURSDAY/...
RIDGING STAYS IN PLACE TODAY. THERE IS A TINY DEPRESSION IN THE
OTHERWISE MASSIVE UPPER LEVEL RIDGE. THE DEPRESSION IS CURRENTLY
ASSOCD WITH A CLUSTER OF STORMS OVER CENTRAL IN. THIS DEPRESSION
SHOULD MOVE EASTWARD THRU THE UPPER OHIO VALLEY AND INTO THE MID
ATLANTIC.
BUT THAT FEATURE MAKES ONLY A SMALL DIP IN MID-LVL TEMPS AND TINY
DECREASE IN STABILITY ON WED. THIS MAY BE ENOUGH TO ALLOW SCT
SHRA/TSRA TO DEVELOP IN THE AFTN OVER THE HIGHER TERRAIN...MAINLY
THE LAURELS AND NRN MTNS. THE 30-40 POPS IN THE MTNS WILL PROBABLY
BE THE HIGHEST POPS WE DRAW FOR QUITE A FEW DAYS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
AN ANOMALOUS UPPER LEVEL RIDGE IS FORECAST TO DOMINATE THE LARGE
SCALE PATTERN OVER THE NORTHEASTERN CONUS INTO EARLY NEXT
WEEK...WITH HIGH PRESSURE TAKING CONTROL AT THE SFC. THIS PATTERN
WILL CONTINUE TO SUPPORT ABOVE-NORMAL TEMPERATURES AND VERY
LIMITED TO NO RAINFALL ACROSS CENTRAL PA THROUGH THE LABOR DAY
WEEKEND.
THE GFS REMAINS MORE BULLISH VS. THE ECMWF WITH CONVECTION ON
FRIDAY. HIGH PRESSURE INITIALLY CENTERED OVER QUEBEC WILL DROP SWD
OVER THE WEEKEND AND BRING SLIGHTLY COOLER AND DRIER/LESS HUMID AIR
INTO THE REGION. NO RISK OF RAIN AGAIN UNTIL PROBABLY NEXT
TUESDAY AS A COLD FRONT APPROACHES FROM THE GREAT LAKES/OH VLY.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
FOG HAS ALREADY CRASHED THE VIZ AT BRADFORD. ELSEWHERE A HAZY
WARM AND HUMID LATE SUMMER EVENING IS IN PROGRESS. THE VFR
CONDITIONS WILL GIVE WAY TO DEVELOPING RESTRICTIONS AS PATCHY
VALLEY FOG FORMS ONCE AGAIN TONIGHT.
MORE CLEAR NIGHTS WITH AM VALLEY FOG AND MOSTLY SUNNY DAYS ARE
EXPECTED FOR THE NEXT SEVERAL DAYS.
OUTLOOK...
THU-SUN...PATCHY AM FOG POSS...MAINLY KIPT/KBFD. OTHERWISE VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...DANGELO
LONG TERM...RXR
AVIATION...LA CORTE
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
620 AM CDT WED SEP 2 2015
.DISCUSSION...UPDATED FOR THE 12Z AVIATION DISCUSSION.
&&
.AVIATION...ISOLATED CONVECTION ONGOING BETWEEN CRP-VCT AS OF
WRITING. WILL EXPECT DEVELOPMENT FARTHER INLAND TO ALI WITH
ADDITIONAL HEATING AS THE DAY PROGRESSES. CIGS DEVELOPING...YET
CONTINUE TO REPORT VFR AT CRP-ALI-VCT...ALTHOUGH BRIEF PERIODS OF
MVFR WILL REMAIN POSSIBLE THROUGH MID MORNING. SATELLITE IMAGERY
IS SHOWING LARGER COVERAGE OF LOW CIG DEVELOPMENT ACROSS THE RIO
GRANDE PLAINS AND WESTERN BRUSH COUNTRY TO AFFECT LRD. WILL EXPECT
MVFR AT LRD TO CONTINUE THROUGH AT LEAST 16Z BEFORE LIFTING TO
VFR. HAVE RAIN CHANCES TAPERING OFF THROUGH THE LATE AFTERNOON
WITH THE LOSS OF HEATING. DID LOWER CLOUDS LATE IN THE
PERIOD...BUT FOR NOW MAINTAINED VFR ALTHOUGH TEMPO MVFR AFTER 09Z
MAY BE ADDED.
&&
.PREV DISCUSSION... /ISSUED 414 AM CDT WED SEP 2 2015/
SHORT TERM (TODAY THROUGH THURSDAY)...THE MID LEVEL LOW/TROUGH IS
STILL HANGING AROUND THE TEXAS COAST PER THE WATER VAPOR IMAGERY.
THIS COMBINED WITH PWATS OF NEAR 2 INCHES DRAPED ALONG THE EASTERN
CWA WILL CONTINUE ISOLATED TO SCATTERED SHOWER AND THUNDERSTORM
DEVELOPMENT...FOCUSING ALONG THE COASTAL CONVERGENCE DURING THE
MORNING HOURS /ESPECIALLY TOWARD THE NORTHERN COASTAL BEND/...THEN
SHIFTING FARTHER INLAND WITH THE SEA BREEZE. HRRR AND TEXAS TECH
MODELS CONTINUE COASTAL ACTIVITY THROUGH THE EARLY AFTERNOON
/WITH TX TECH MODEL BEING THE MORE AGGRESSIVE OF THE TWO/ BEFORE
SHIFTING FARTHER INLAND...SO HAVE EXTENDED CHANCE POPS FARTHER
EAST IN THE AFTERNOON HOURS. ACTIVITY WILL WANE WITH THE LOSS OF
HEATING...BUT A SIMILAR SITUATION IS EXPECTED TO REDEVELOP LATER
TONIGHT THROUGH THURSDAY. TEMPERATURES WILL HEAVILY RELY ON ACTUAL
RAINFALL AND CLOUD COVERAGE...HOWEVER MAINTAINED RELATIVELY
PERSISTENT WITH TEMPS ACROSS THE EASTERN ZONES...BUT DID RAISE
TEMPS OUT WEST BY A FEW DEGREES.
LONG TERM (THURSDAY NIGHT THROUGH TUESDAY)...CONVECTIVE CHANCES
/ALBEIT RATHER LOW/ WILL CONTINUE TO BE PRIMARY FORECAST CHALLENGE
FOR THE LONG TERM PERIOD. UPPER LEVEL DYNAMICAL CONVECTIVE SUPPORT
WILL DIMINISH BY LATE THIS WEEK WITH PRIMARY CONVECTIVE CHANCES
BECOMING DIURNALLY SUPPORTED /COMMON PATTERN FOR THIS TIME OF YEAR/.
SUFFICIENT DEEP LAYER MOISTURE /PWATS GENERALLY 1.75 TO 2 INCHES/ IS
PROG TO PERSIST THROUGH MOST OF THE LONG TERM PERIOD. ISOLATED TO
SCATTERED CONVECTION IS PROG TO DEVELOP ACROSS MARINE AREAS AND THE
COASTAL COUNTIES THURSDAY NIGHT AS A NOCTURNALLY DRIVEN UNSTABLE
AIRMASS DEVELOPS ALONG THE COAST AND JUST OFFSHORE WITH SBCAPES PROG
TO BE AROUND 2500 J/KG. CONVECTIVE ACTIVITY /SCATTERED AT BEST/
SHOULD DEVELOP FURTHER IN AREAL COVERAGE ACROSS THE COASTAL PLAINS
AND NORTHERN COASTAL BEND BY MID MORNING FRIDAY WITH ACTIVITY THEN
SHIFTING INLAND DURING THE AFTERNOON. CONVECTIVE COVERAGE ON
SATURDAY IS EXPECTED TO BE MUCH MORE ISOLATED AS MID LEVEL TEMPS ARE
PROG TO INCREASE WITH STRENGTHENING RIDGING...THUS CAPPING THE
ATMOSPHERE TO AN EXTENT. EVEN WARMER MID LEVEL TEMPS ON SUNDAY
SHOULD KEEP MOST AREAS DRY. MID LEVEL RIDGE CENTER IS THEN PROG TO
SHIFT WESTWARD SLOWLY EARLY NEXT WEEK...ALLOWING FOR A RETURN OF
ISOLATED TO SCATTERED CONVECTION /AGAIN BEST CHANCES ALONG THE COAST
AND OFFSHORE AT NIGHT/MORNING AND INLAND DURING THE DAY/. ASIDE FROM
CONVECTION...ANOTHER ITEM OF CONCERN FOR THE LONG TERM PERIOD WILL
BE HEAT INDICES. A SURGE OF HIGHER NEAR SURFACE MOISTURE IS PROG TO
OCCUR FOR OVER THE UPCOMING HOLIDAY WEEKEND. AFTERNOON HEAT INDICES
OVER THE LABOR DAY WEEKEND ARE CURRENTLY EXPECTED TO RANGE FROM 105
TO 110 DEGREES WITH HIGH TEMPS IN THE MID 90S TO AROUND 100...AND
AROUND 90 AT THE BEACH. THOSE WITH OUTDOOR ACTIVITIES THIS WEEKEND
ARE URGED TO DRINK PLENTY OF WATER AND TO SEEK SHADE WHEN POSSIBLE.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 90 75 90 76 93 / 30 20 30 20 30
VICTORIA 89 73 89 74 93 / 30 30 40 20 30
LAREDO 98 76 98 78 100 / 10 10 20 10 10
ALICE 92 74 93 73 97 / 30 10 40 10 30
ROCKPORT 85 77 87 79 91 / 40 30 40 30 30
COTULLA 97 74 97 77 99 / 10 10 20 10 10
KINGSVILLE 90 75 91 76 96 / 30 20 40 10 20
NAVY CORPUS 85 77 87 79 91 / 40 30 40 20 30
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
CB/85...AVIATION
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
414 AM CDT WED SEP 2 2015
.SHORT TERM (TODAY THROUGH THURSDAY)...THE MID LEVEL LOW/TROUGH IS
STILL HANGING AROUND THE TEXAS COAST PER THE WATER VAPOR IMAGERY.
THIS COMBINED WITH PWATS OF NEAR 2 INCHES DRAPED ALONG THE EASTERN
CWA WILL CONTINUE ISOLATED TO SCATTERED SHOWER AND THUNDERSTORM
DEVELOPMENT...FOCUSING ALONG THE COASTAL CONVERGENCE DURING THE
MORNING HOURS /ESPECIALLY TOWARD THE NORTHERN COASTAL BEND/...THEN
SHIFTING FARTHER INLAND WITH THE SEA BREEZE. HRRR AND TEXAS TECH
MODELS CONTINUE COASTAL ACTIVITY THROUGH THE EARLY AFTERNOON
/WITH TX TECH MODEL BEING THE MORE AGGRESSIVE OF THE TWO/ BEFORE
SHIFTING FARTHER INLAND...SO HAVE EXTENDED CHANCE POPS FARTHER
EAST IN THE AFTERNOON HOURS. ACTIVITY WILL WANE WITH THE LOSS OF
HEATING...BUT A SIMILAR SITUATION IS EXPECTED TO REDEVELOP LATER
TONIGHT THROUGH THURSDAY. TEMPERATURES WILL HEAVILY RELY ON ACTUAL
RAINFALL AND CLOUD COVERAGE...HOWEVER MAINTAINED RELATIVELY
PERSISTENT WITH TEMPS ACROSS THE EASTERN ZONES...BUT DID RAISE
TEMPS OUT WEST BY A FEW DEGREES.
&&
.LONG TERM (THURSDAY NIGHT THROUGH TUESDAY)...CONVECTIVE CHANCES
/ALBEIT RATHER LOW/ WILL CONTINUE TO BE PRIMARY FORECAST CHALLENGE
FOR THE LONG TERM PERIOD. UPPER LEVEL DYNAMICAL CONVECTIVE SUPPORT
WILL DIMINISH BY LATE THIS WEEK WITH PRIMARY CONVECTIVE CHANCES
BECOMING DIURNALLY SUPPORTED /COMMON PATTERN FOR THIS TIME OF YEAR/.
SUFFICIENT DEEP LAYER MOISTURE /PWATS GENERALLY 1.75 TO 2 INCHES/ IS
PROG TO PERSIST THROUGH MOST OF THE LONG TERM PERIOD. ISOLATED TO
SCATTERED CONVECTION IS PROG TO DEVELOP ACROSS MARINE AREAS AND THE
COASTAL COUNTIES THURSDAY NIGHT AS A NOCTURNALLY DRIVEN UNSTABLE
AIRMASS DEVELOPS ALONG THE COAST AND JUST OFFSHORE WITH SBCAPES PROG
TO BE AROUND 2500 J/KG. CONVECTIVE ACTIVITY /SCATTERED AT BEST/
SHOULD DEVELOP FURTHER IN AREAL COVERAGE ACROSS THE COASTAL PLAINS
AND NORTHERN COASTAL BEND BY MID MORNING FRIDAY WITH ACTIVITY THEN
SHIFTING INLAND DURING THE AFTERNOON. CONVECTIVE COVERAGE ON
SATURDAY IS EXPECTED TO BE MUCH MORE ISOLATED AS MID LEVEL TEMPS ARE
PROG TO INCREASE WITH STRENGTHENING RIDGING...THUS CAPPING THE
ATMOSPHERE TO AN EXTENT. EVEN WARMER MID LEVEL TEMPS ON SUNDAY
SHOULD KEEP MOST AREAS DRY. MID LEVEL RIDGE CENTER IS THEN PROG TO
SHIFT WESTWARD SLOWLY EARLY NEXT WEEK...ALLOWING FOR A RETURN OF
ISOLATED TO SCATTERED CONVECTION /AGAIN BEST CHANCES ALONG THE COAST
AND OFFSHORE AT NIGHT/MORNING AND INLAND DURING THE DAY/. ASIDE FROM
CONVECTION...ANOTHER ITEM OF CONCERN FOR THE LONG TERM PERIOD WILL
BE HEAT INDICES. A SURGE OF HIGHER NEAR SURFACE MOISTURE IS PROG TO
OCCUR FOR OVER THE UPCOMING HOLIDAY WEEKEND. AFTERNOON HEAT INDICES
OVER THE LABOR DAY WEEKEND ARE CURRENTLY EXPECTED TO RANGE FROM 105
TO 110 DEGREES WITH HIGH TEMPS IN THE MID 90S TO AROUND 100...AND
AROUND 90 AT THE BEACH. THOSE WITH OUTDOOR ACTIVITIES THIS WEEKEND
ARE URGED TO DRINK PLENTY OF WATER AND TO SEEK SHADE WHEN POSSIBLE.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 90 75 90 76 93 / 30 20 30 20 30
VICTORIA 89 73 89 74 93 / 30 30 40 20 30
LAREDO 98 76 98 78 100 / 10 10 20 10 10
ALICE 92 74 93 73 97 / 30 10 40 10 30
ROCKPORT 85 77 87 79 91 / 40 30 40 30 30
COTULLA 97 74 97 77 99 / 10 10 20 10 10
KINGSVILLE 90 75 91 76 96 / 30 20 40 10 20
NAVY CORPUS 85 77 87 79 91 / 40 30 40 20 30
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
CB/85...SHORT TERM
RH/79...LONG TERM
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1136 PM CDT TUE SEP 1 2015
.DISCUSSION...
06Z TAF DISCUSSION IN AVIATION SECTION.
&&
.AVIATION...
WATER VAPOR IMAGERY STILL SHOWING UPPER LOW OVER THE REGION BUT
LOOKS LIKE BEST LARGE SCALE ASCENT HAS MOVED EAST. MODELS STILL
SHOWING CONVECTION DEVELOPING IN THE MORNING HOURS AND MOVING
INLAND BUT HRRR RUNS HAVE BECOME LESS ROBUST WITH CONVECTIVE
DEVELOPMENT. THE LATEST 00Z NAM DID NOT INITIALIZE WELL WITH
CONVECTION BUT LOOKS LIKE WRF-ARW SEEMS TO BE ON TRACK. GFS KEEPS
CONVECTIVE DEVELOPMENT IN THE AFTERNOON. OVERALL LEAN A BIT MORE
ON THE HRRR/WRF TRENDS WHICH SUPPORT ON GOING FORECAST.
THIS MEANS MAINLY VFR CIGS TONIGHT EXCEPT WHERE CONVECTION
DEVELOPS. EXPECT CONVECTION ALONG THE COAST TO MOVE INLAND THROUGH
THE MORNING. ANY SHRA/TSRA SHOULD BE WEAKENING THROUGH THE
AFTERNOON.
39
&&
.PREV DISCUSSION... /ISSUED /
DISCUSSION...
SEE THE UPDATE DISCUSSION BELOW.
UPDATE...
THE ELONGATED UPPER LEVEL LOW PRESSURE TROUGH WAS OVER SE TX AT
MID EVENING. LOW PRESSURE IN THE FLOW WAS ALSO LOCATED BETWEEN
FREEPORT AND GALVESTON. THE MAJORITY OF THE RAINFALL WAS ALSO
LOCATED OFF TO THE EAST TOWARD THE LA COAST. THE LATEST HIGHER
RESOLUTION MODELS WERE FORECASTING REDEVELOPMENT MANLY ALONG AND
OFF THE COAST LATER TONIGHT...ALTHOUGH THE COVERAGE WAS LESS THAN
PREVIOUSLY ANTICIPATED. SLIGHTLY COOLER TEMPERATURES WERE ALSO IN
PLACE ACROSS THE AREA. BECAUSE OF THIS...UPDATED THE FORECAST AND
REVISED DOWN THE POPS...AND TWEAKED TEMPERATURES.
40
PREV DISCUSSION... /ISSUED /
DISCUSSION...
00Z TAF DISCUSSION IN AVIATION SECTION.
AVIATION...
UPPER LEVEL LOW OVER SE TX SUPPORTED SCT SHRA/TSRA MAINLY SOUTH
OF KIAH WHICH IMPACTED KGLS THE MOST. SHRA/TSRA ARE PRETTY CLOSE
TO BEING DONE WITH A FEW SHRA W OF KLBX. WILL NOT CARRY ANY
MENTION OF CONVECTION OVERNIGHT FOR THE TAFS AS BOUNDARY LAYER
LOSES HEATING AND HAS STABILIZED WITH CONVECTION.
TOMORROW WILL BE ANOTHER CHALLENGE WITH CONVECTION. TIMING OF
VCSH/VCTS FOR TOMORROW MORNING SIMILAR TODAY WITH ACTIVITY
DEVELOPING ALONG THE COAST AND PUSHING INLAND. HARD TO SAY HOW
MUCH THE ATMOSPHERE HAS BEEN STABILIZED WITH CONVECTION TODAY
SINCE UPPER LOW STILL SHOULD BE IN THE AREA AND PRECIP WATER
VALUES WILL BE HANGING AROUND 2 INCHES. QUITE POSSIBLE THAT
SHRA/TSRA COULD DEVELOP FARTHER INLAND BUT MORE ISO IN NATURE.
TAFS WILL MENTION VCSH DURING THE EARLY AFTERNOON BUT WAIT FOR 00Z
MODEL RUNS TO GET A BETTER HANDLE ON CONVECTIVE TRENDS TOMORROW.
39
PREV DISCUSSION... /ISSUED /
DISCUSSION...
SHOWER AND THUNDERSTORM COVERAGE HAS DECREASED ACROSS SOUTHEAST TEXAS
THIS AFTERNOON. PARTS OF THE AREA...ESPECIALLY IN AND AROUND GALVESTON
ISLAND...SAW SOME LOCALLY HEAVY RAINFALL OF 2 TO OVER 4 INCHES WHICH
LED TO SOME FLASH FLOODING. WHILE THE MID/UPPER LEVEL LOW APPEARS TO
HAVE MOVED OFF TO THE NORTHEAST...ANOTHER CIRCULATION CENTER HAS FORMED
IN/AROUND THE MATAGORDA BAY AREA. SOME SHOWERS AND THUNDERSTORMS HAVE
BEGUN TO DEVELOP IN ASSOCIATION WITH THIS FEATURE...AND THINK WE COULD
SEE SOME MORE DEVELOPMENT THIS EVENING AND OVERNIGHT IN/AROUND THIS
AREA. FOR THE NEXT SEVERAL DAYS...WILL GENERALLY CALL FOR LOWER POPS
WELL INLAND (WHERE MID/UPPER LEVEL HIGH PRESSURE MIGHT BEGIN TO BECOME
THE DOMINATE FEATURE) AND HIGHER POPS NEAR THE COAST AND OFFSHORE (WHERE
BOTH A MID/UPPER LEVEL TROF AXIS AND PRECIPITABLE WATER VALUES AROUND
2 INCHES WILL CONTINUE TO RESIDE). LOCALLY HEAVY RAINFALL COULD DEVELOP
AGAIN WITH THESE FUTURE STORMS...AND CANNOT RULE OUT FUNNEL CLOUD AND/OR
WATERSPOUT FORMATIONS TOO. IT WILL OBVIOUSLY BE WARMER WELL INLAND WITH
LESS CLOUD COVER AND FEWER STORMS...AND NOT AS WARM CLOSER TO THE COAST
AND OFFSHORE WHERE THE BULK OF CLOUDS AND STORMS WILL BE LOCATED. BY
THE END OF THE WEEK AND OVER THE HOLIDAY WEEKEND...IT LOOKS LIKE WE
WILL BE GETTING BACK INTO A MORE DIURNALLY DRIVEN PATTERN OF A CHANCE
OF MAINLY LATE MORNING THROUGH EARLY EVENING SHOWERS AND THUNDERSTORMS.
42
MARINE...
A FEW SHOWERS AND THUNDERSTORMS CONTINUE TO LINGER ACROSS THE MARINE
ZONES THIS AFTERNOON. HIGH RESOLUTION GUIDANCE SHOWS THAT A BRIEF
BREAK IN THIS ACTIVITY WILL BE POSSIBLE THIS EVENING TO LATE TONIGHT
BEFORE AN UPPER DISTURBANCE MOVES OVER THE NORTHWEST GULF OF MEXICO.
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP
ALONG THE COAST EARLY WEDNESDAY MORNING AND REMAIN THROUGH THE DAY
AS THIS HAPPENS... WITH HEAVY RAINFALL AND GUSTY WINDS ACCOMPANYING
THIS ACTIVITY. VISIBILITIES MAY BE LIMITED TO 1 NAUTICAL MILE OR
LESS AT TIMES DUE TO HEAVY RAINFALL. ALSO CANNOT RULE OUT AN
ISOLATED WATERSPOUT THREAT DURING THE DAY WITH AMPLE TROPICAL
MOISTURE AND A LIGHT WIND PROFILE IN PLACE ABOVE THE SURFACE. EXPECT
SHOWERS AND THUNDERSTORMS TO CLEAR THE MARINE AREAS SOMETIME
WEDNESDAY EVENING BUT PERIODS OF SHOWERS AND THUNDERSTORMS WILL
REMAIN WILL POSSIBLE THROUGH THE END OF THE WEEK. OTHERWISE... WEAK
TO OCCASIONALLY MODERATE ONSHORE FLOW IS EXPECTED TO PERSIST INTO
THE HOLIDAY WEEKEND WITH SEAS GENERALLY 1-3 FEET.
HUFFMAN
PREV DISCUSSION...
AVIATION...
FOR THE 18Z TAFS... MAIN AVIATION CONCERNS CENTER AROUND ONGOING
TSRA/SHRA ACTIVITY AT THE TERMINALS WITH ADDITIONAL DEVELOPMENT
EXPECTED AGAIN ON WEDNESDAY.
SCATTERED TO NUMEROUS THUNDERSTORMS ASSOCIATED WITH A MID TO
UPPER LEVEL DISTURBANCE CONTINUE TO MOVE ACROSS THE TERMINALS THIS
AFTERNOON. BULK OF ACTIVITY IS CONCENTRATED NEAR AND NORTH OF CXO
WITH AN ADDITIONAL BROKEN LINE CLEARING THE HOUSTON TERMINALS AND
SOUTHWARD. STARTING TO SEE ADDITIONAL ACTIVITY DEVELOP OVER THE
GULF AND THIS WILL NEED TO BE MONITORED FOR THE COASTAL SITES THIS
AFTERNOON. HAVE VCTS AT ALL TERMINALS THROUGH 21Z AS ACTIVITY
EXITS THE AREA... WITH ANOTHER ROUND OF SHRA/TSRA POSSIBLE AGAIN
EARLY WEDNESDAY MORNING OVER THE COASTAL WATERS AND SPREADING
NORTH INTO THE TERMINALS THROUGH WEDNESDAY AFTERNOON AS THE
AFOREMENTIONED DISTURBANCE DRAWS CLOSER TO THE REGION.
OTHERWISE... LIGHT AND VARIABLE TO LIGHT AND SOUTHERLY WINDS
EXPECTED FOR THE TERMINALS THROUGH THE PERIOD WITH VFR CONDITIONS
OUTSIDE OF TSRA/SHRA ACTIVITY. SOME STRONGER WIND GUSTS
APPROACHING 20 KNOTS WILL BE POSSIBLE IN CONVECTIVE ACTIVITY AS
WELL AS MVFR VISIBILITIES. COULD SEE A FEW HOURS OF MVFR
VISIBILITIES AT CXO AGAIN WEDNESDAY MORNING AS WELL AT CXO... BUT
ONLY INCLUDING A TEMPO MENTION ATTM.
HUFFMAN
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 72 91 73 94 73 / 10 30 20 30 10
HOUSTON (IAH) 72 88 73 92 73 / 20 50 30 40 20
GALVESTON (GLS) 78 87 79 88 79 / 40 60 40 50 30
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...40
AVIATION/MARINE...39
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
148 PM EDT WED SEP 2 2015
.SYNOPSIS...
A RIDGE OF HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH THE
END OF THE WEEK. UPPER LEVEL DISTURBANCES TRACKING THROUGH THE
RIDGING WILL RESULT IN WIDELY SCATTERED MAINLY DIURNAL SHOWERS
AND STORMS INTO FRIDAY. A WEAK BACKDOOR COLD FRONT WILL DROP
SOUTH THROUGH THE AREA BY THE END OF WEEK BRINGING SOMEWHAT DRIER
AND COOLER AIR FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1255 PM EDT WEDNESDAY...
OUR LATEST FORECAST WILL REFLECT A CHANGE UPWARD BY AN AVERAGE OF
TWO TO THREE DEGREES OF THE HIGH TEMPERATURES. SEVERAL LOCATIONS
ARE ALREADY WITHIN A DEGREE OR TWO OF THE EARLIER FORECAST HIGHS.
WITH AT LEAST FOUR HOURS OF ADDITIONAL HEATING AT A CONSERVATIVE
DEGREE PER HOUR...AN INCREASE IN THE FORECAST HIGHS ARE WARRANTED.
ANOTHER ADJUSTMENT HAS BEEN TO THE COVERAGE OF ISOLATED SHOWERS
ACROSS THE SOUTHERN HALF OF THE CREST OF THE BLUE RIDGE AND
ADJOINING FOOTHILLS FROM THIS POINT ONWARD. INITIATION COMMENCED
ABOUT AN HOUR OR TWO EARLIER THAN PREVIOUSLY PREDICTED. OUR
FORECAST WILL NOW REFLECT THIS COVERAGE AS ONGOING. NO OTHER
NOTABLE CHANGES AT THIS TIME.
AS OF 930 AM EDT WEDNESDAY...
EARLY MORNING FOG HAS DISSIPATED IN ALL BUT PARTS OF THE
GREENBRIER AND NEW RIVER VALLEY REGIONS. HOWEVER...BY 1100 AM...AT
VAST MAJORITY...IF NOT ALL...OF THIS FOG WILL HAVE DISSIPATED AS
WELL. PRECIPITATION COVERAGE ACROSS THE REGION CURRENTLY IS ZERO.
THERE WERE A FEW ISOLATED SHOWERS OVER BUCKINGHAM COUNTY AROUND
THE TOP THE HOUR..BUT THESE HAVE SINCE FADED. LATEST MESOSCALE
MODELS PAINTS VERY LITTLE IF ANY PRECIPITATION ACROSS THE
NORTHERN PARTS OF THE AREA THROUGH 17Z/1PM...AND THEN START
RAMPING UP THE COVERAGE AFTER THAT TIME. HAVE TWEAKED THE
PROBABILITY OF PRECIPITATION GRIDS AND THE WEATHER GRIDS TO BETTER
REFLECT THIS TREND. NO OTHER NOTABLE CHANGES AT THIS TIME.
AS OF 240 AM EDT WEDNESDAY...
OVERALL HOT AND HUMID WEATHER FOR EARLY SEPTEMBER TO PERSIST TODAY AS
SURFACE HIGH PRESSURE REMAINS IN PLACE ACROSS THE MOUNTAINS. HOWEVER
SHORTWAVE ENERGY IN THE FORM OF AN OPENING UPPER LOW ACROSS THE OHIO
VALLEY WILL RIDE SOUTHEAST THROUGH THE 5H RIDGE AND OVER THE NORTHERN
HALF OF THE AREA THIS AFTERNOON. THIS SHOULD RESULT IN BETTER LIFT
ESPCLY ALONG AND JUST SOUTH OF THE INTERSTATE 64 CORRIDOR EARLY ON AND
ACROSS THE EASTERN HALF THROUGH LATE IN THE DAY. LATEST GUIDANCE ALSO
SHOWING BETTER INSTABILITY WITH A LITTLE MORE COOLING ALOFT...BUT STILL
UNCERTAINTY WITH COVERAGE GIVEN OVERALL BROAD SUBSIDENCE IN PLACE UNDER
RATHER WARM 5H TEMPS. CURRENT SPC/RNK WRF SOLUTIONS ALONG WITH THE
LATEST HRRR REMAIN THE MOST WIDESPREAD WITH SHRA/TSRA NORTH HALF AND
ALONG THE BLUE RIDGE. THIS WHILE MOST OTHER SOLUTIONS INCLUDING
ENSEMBLES PRODUCING LESS INCLUDING ONLY WIDELY SCATTERED SHALLOW
CONVECTION MAINLY CONFINED FROM THE VIRGINIA HIGHLANDS EAST TO AROUND
KLYH FOR THE MOST PART. THEREFORE ALIGNED HIGHEST CHANCE POPS ACROSS
THE FAR NORTH WITH A PERIOD OF LOWER CHANCES SOUTH/EAST DURING MID/LATE
AFTERNOON AND ONLY ISOLATED COVERAGE FAR SW. GIVEN WEAK FLOW ALOFT NOT
EXPECTING MUCH OF A SEVERE THREAT BUT COULD SEE A BIT MORE CLUSTERING
OF SLOW MOVING CONVECTION RIGHT NEAR THE CORE OF THE UPPER WAVE LATE.
OTHERWISE LOOKING AT MAINLY PC WITH MID DECK EARLY...THEN MORE CU THIS
AFTERNOON WITH HIGHS AGAIN REACHING THE LOW 90S EAST AND WELL INTO THE
80S ELSEWHERE PENDING TIMING OF CONVECTIVE INITIATION.
IMPULSE PASSES THIS EVENING LEAVING THE REGION IN BETWEEN WAVES AND
UNDER SURFACE HIGH PRESSURE. THIS SHOULD ALLOW MOST CONVECTION TO FADE
BY MIDNIGHT GIVEN LOSS OF HEATING AND SOME OVERNIGHT CLEARING PER WEAK
NW FLOW ALOFT IN THE WAKE OF THE MID LEVEL SYSTEM. THUS KEEPING SOME
LOW END CHANCE POPS GOING MAINLY EAST THIS EVENING BEFORE TRENDING DRY
WITH FOG AGAIN OVERNIGHT. LOWS PERHAPS SLIGHTLY COOLER GIVEN SOME DROP
IN DEWPOINTS AND ESPCLY WHERE ANY COOLING EVENING RAINFALL OCCURS BUT
STILL MOSTLY LOW/MID 60S MOUNTAINS TO UPPER 60S EAST.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
AS OF 415 AM EDT WEDNESDAY...
WEAK UPPER-LEVEL SHORT WAVE WILL BE DISSIPATING ACROSS NORTH
CAROLINA DRIFTING SLOWLY INTO THE SOUTHEAST STATES WHERE IT
APPEARS IT IS DESTINED TO BECOME A WEAK CUTOFF THAT WILL
RETROGRADE/LINGER ACROSS THE SOUTHEAST/MID-SOUTH INTO NEXT WEEK AS
A LARGE HIGH AMPLITUDE UPPER RIDGE CONTINUES TO BUILD FROM THE
SOUTH CENTRAL/CENTRAL U.S. INTO SOUTHEAST CANADA AND THE NORTHEAST
U.S. OVER THE TOP OF THE WEAK CUTOFF LOW. UPPER SUPPORT WILL BE
MINIMAL AT BEST WITH BEST DYNAMICS...WHAT THEY ARE...HAVING
DRIFTED SOUTH OF THE AREA. ANY CONVECTION WILL LARGELY BE THE
RESULT OF DIFFERENTIAL HEATING AND FOCUSED PRIMARILY ACROSS THE
WESTERN MOUNTAINS. REALLY CANNOT SUPPORT MUCH MORE THAN 30 POPS AT
BEST.
BY FRIDAY...A LARGE SURFACE HIGH DEVELOPING ACROSS THE NORTHEAST
U.S. UNDERNEATH THE MAMMOTH UPPER RIDGE WILL BEGIN TO PUSH A
BACKDOOR FRONT FROM THE MID-ATLANTIC SOUTHWESTWARD. UPPER DYNAMICS
ARE VERY WEAK...BUT A MARKED DEWPOINT GRADIENT WILL EXIST ALONG
THE SOUTHWESTWARD ADVANCING BOUNDARY AS VERY DRY AIR ADVECTS
SOUTHWEST INTO NORTHERN VA. THIS SHOULD BE SUFFICIENT TO SUPPORT
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS...WITH THE BEST
COVERAGE SHIFTING SOUTHWEST TOWARD EVENING. INSTABILITY IS QUITE
NOTABLE ACROSS THE REGION IN ADVANCE OF THIS BACKDOOR FRONT...SO
EVEN WITH WEAK DYNAMICS...WITH THE NOTED INSTABILITY AND PWATS IN
THE 1.5 TO 1.7 INCH RANGE...30-40 PERCENT POPS SEEMS REASONABLE.
FOR SATURDAY...THE BACKDOOR FRONT CONTINUES TO DRIFT SOUTHWEST AND
SHOULD BE LOCATED FROM CENTRAL WV THROUGH SOUTHWEST VA...NEAR THE
I-77 CORRIDOR...INTO CENTRAL NC. VERY DRY AIR IS NOTED ADVECTING
INTO THE REGION FROM THE NORTHEAST WITH DEWPOINTS DROPPING INTO
THE 50S AND PWATS FALLING TO NEAR 0.50 INCH ACROSS THE NORTHEAST
PART OF THE CWA. ANY CONVECTION SATURDAY SHOULD BE LIMITED TO THE
I-77 CORRIDOR AND POINTS WESTWARD...PRIMARILY DURING THE
AFTERNOON/EVENING.
TEMPERATURES WILL REMAIN WELL ABOVE NORMAL THURSDAY AND FRIDAY
AHEAD OF THE BACKDOOR FRONT...WITH MAX TEMPS WELL INTO THE
80S...NEAR 90 ACROSS THE PIEDMONT. MIN TEMPS WILL HOLD MOSTLY IN
THE 60S TO EVEN NEAR 70 ACROSS THE PIEDMONT. THESE READINGS ARE
AROUND 5 AND 10 DEGREES ABOVE NORMAL...RESPECTIVELY. MOS GUIDANCE
HAS BEEN TRENDING TOO MUCH TOWARD CLIMATOLOGY...SO NEEDED TO NUDGE
UP MOST AREAS FROM 2-3 DEGREES TO BETTER MATCH WHAT HAS BEEN
OCCURRING RECENTLY.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 445 AM EDT WEDNESDAY...
THE FOCUS THROUGH THE PERIOD WILL BE ON THE AFOREMENTIONED WEAK
AND INCREASING BROAD UPPER LOW ANCHORED ACROSS THE SOUTHEAST/MID-
SOUTH PART OF THE U.S. OUR CWA WILL BE STUCK IN THE TRANSITION
ZONE BETWEEN THIS INCREASINGLY MOIST/UNSTABLE AIR MASS TO THE
SOUTH AND THE PERSISTING UPPER RIDGE AND ASSOCIATED
SUBSIDENCE/VERY DRY AND WARM AIR MASS ACROSS THE MID-ATLANTIC
REGION. SHOWER/THUNDERSTORM CHANCES WILL GRADUALLY CREEP NORTHWARD
THROUGH THE PERIOD...BUT LIKELY REMAIN CONFINED TO AREAS WEST OF
I-77 SUNDAY...THEN CREEP FURTHER NORTH TOWARD THE U.S. 460
CORRIDOR BY MONDAY AND MUCH OF THE CWA BY TUESDAY. THE BEST
CHANCES THROUGHOUT THE PERIOD WILL REMAIN ACROSS THE WESTERN NC
MOUNTAINS. THE MODELS HAVE CONTINUALLY DELAYED THE ARRIVAL OF A
FRONT TOWARD THE MID PART OF NEXT WEEK...AND WITH THE UPPER RIDGE
SANDWICHED IN BETWEEN THE LOW PRESSURE AREA TO THE SOUTH AND THE
STRONGER WESTERLIES ALONG THE CANADIAN BORDER...IT MAY BE SOME
TIME BEFORE IT ACTUALLY REACHES OUR AREA. HENCE...SUMMER APPEARS
DESTINED TO HANG ON MUCH OF NEXT WEEK.
MAX TEMPS SHOULD BE NEAR NORMAL AT THE BEGINNING OF THE
PERIOD...BUT PERHAPS STILL SLIGHTLY ABOVE NORMAL WEST OF I-77. MIN
TEMPS WILL REMAIN NEAR NORMAL TO SLIGHTLY ABOVE NORMAL FAR
SOUTHWEST. MAX AND MIN TEMPS WILL CREEP TO SLIGHTLY ABOVE NORMAL
LEVELS AGAIN AS WE MOVE INTO EARLY NEXT WEEK.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 135 PM EDT WEDNESDAY...
A WEAK UPPER WAVE WAS MAKING PROGRESS EASTWARD NEAR THE MASON-
DIXON LINE. THIS FEATURE...ALONG WITH DAYTIME HEATING...WAS
TRIGGERING SOME ISOLATED TO SCATTERED SHOWERS ACROSS MAINLY
NORTHERN PART OF OUR REGION. SO FAR...THUNDERSTORMS HAVE REMAINED
TO OUR NORTH...BUT CANNOT BE RULED OUT LATER THIS
AFTERNOON...ESPECIALLY ACROSS NORTHERN AND EASTERN PARTS OF THE
REGION HEADING INTO THE EVENING HOURS. MOST LOCATIONS WILL REMAIN
VISUAL FLIGHT RULES THROUGH THE EARLY EVENING. THE EXCEPTION WILL
BE ISOLATED...AND BRIEF AND ISOLATED SUB-VISUAL FLIGHT RULES
CONDITIONS UNDER ANY OF THE STRONGER RAIN SHAFTS OF THE STRONGER
SHOWERS AND STORMS.
OVERNIGHT...LOOK FOR A RETURN OF MOUNTAIN AND RIVER VALLEY
MIST AND FOG...ESPECIALLY FOR ANY LOCATIONS THAT RECEIVE
MEASURABLE PRECIPITATION THIS AFTERNOON AND EVENING. PATCHY
MARGINAL VISUAL FLIGHT RULES CEILINGS WILL ALSO BE POSSIBLE
ACROSS THE MOUNTAINS.
FOR THURSDAY...ANY SUB-VISUAL FLIGHT RULES CONDITIONS WILL IMPROVE
TO VISUAL FLIGHT RULES BY 14Z/10AM. SOME ISOLATED SHOWERS ARE
EXPECTED TO DEVELOP...ESPECIALLY OVER THE MOUNTAINS BY 16Z/NOON.
EXTENDED AVIATION DISCUSSION...
THE REGION WILL CONTINUE TO UNDER THE INFLUENCE OF A HOT AND HUMID
DAYTIME AIRMASS THROUGH AT LEAST FRIDAY. ANTICIPATE A CONTINUATION
OF ISOLATED TO SCATTERED AFTERNOON SHOWERS...AND A FEW
STORMS...THAT LINGER INTO THE EVENING BEFORE DISSIPATING. COVERAGE
WILL BE GREATER ON FRIDAY AS COMPARED TO THURSDAY WITH THE
APPROACH OF A BACKDOOR COLD FRONT.
DRIER AIR WILL START WORKING ITS WAY INTO THE AREA FOR THE
WEEKEND. LOOK FOR A TREND TOWARDS LESS COVERAGE OF
PRECIPITATION...ESPECIALLY ON SUNDAY. THIS DRIER PATTERN WILL
CONTINUE INTO MONDAY.
&&
.EQUIPMENT...
AS OF 400 PM EDT TUESDAY...
THE DEW POINT READING AT KJFZ...RICHLANDS VA AWOS...IS INCORRECT.
AT THIS TIME WE DO NOT KNOW WHEN THIS SENSOR WILL BE REPAIRED.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/NF
NEAR TERM...DS/JH
SHORT TERM...RAB
LONG TERM...AMS/RAB
AVIATION...DS
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1258 PM EDT WED SEP 2 2015
.SYNOPSIS...
A RIDGE OF HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH THE
END OF THE WEEK. UPPER LEVEL DISTURBANCES TRACKING THROUGH THE
RIDGING WILL RESULT IN WIDELY SCATTERED MAINLY DIURNAL SHOWERS
AND STORMS INTO FRIDAY. A WEAK BACKDOOR COLD FRONT WILL DROP
SOUTH THROUGH THE AREA BY THE END OF WEEK BRINGING SOMEWHAT DRIER
AND COOLER AIR FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1255 PM EDT WEDNESDAY...
OUR LATEST FORECAST WILL REFLECT A CHANGE UPWARD BY AN AVERAGE OF
TWO TO THREE DEGREES OF THE HIGH TEMPERATURES. SEVERAL LOCATIONS
ARE ALREADY WITHIN A DEGREE OR TWO OF THE EARLIER FORECAST HIGHS.
WITH AT LEAST FOUR HOURS OF ADDITIONAL HEATING AT A CONSERVATIVE
DEGREE PER HOUR...AN INCREASE IN THE FORECAST HIGHS ARE WARRANTED.
ANOTHER ADJUSTMENT HAS BEEN TO THE COVERAGE OF ISOLATED SHOWERS
ACROSS THE SOUTHERN HALF OF THE CREST OF THE BLUE RIDGE AND
ADJOINING FOOTHILLS FROM THIS POINT ONWARD. INITIATION COMMENCED
ABOUT AN HOUR OR TWO EARLIER THAN PREVIOUSLY PREDICTED. OUR
FORECAST WILL NOW REFLECT THIS COVERAGE AS ONGOING. NO OTHER
NOTABLE CHANGES AT THIS TIME.
AS OF 930 AM EDT WEDNESDAY...
EARLY MORNING FOG HAS DISSIPATED IN ALL BUT PARTS OF THE
GREENBRIER AND NEW RIVER VALLEY REGIONS. HOWEVER...BY 1100 AM...AT
VAST MAJORITY...IF NOT ALL...OF THIS FOG WILL HAVE DISSIPATED AS
WELL. PRECIPITATION COVERAGE ACROSS THE REGION CURRENTLY IS ZERO.
THERE WERE A FEW ISOLATED SHOWERS OVER BUCKINGHAM COUNTY AROUND
THE TOP THE HOUR..BUT THESE HAVE SINCE FADED. LATEST MESOSCALE
MODELS PAINTS VERY LITTLE IF ANY PRECIPITATION ACROSS THE
NORTHERN PARTS OF THE AREA THROUGH 17Z/1PM...AND THEN START
RAMPING UP THE COVERAGE AFTER THAT TIME. HAVE TWEAKED THE
PROBABILITY OF PRECIPITATION GRIDS AND THE WEATHER GRIDS TO BETTER
REFLECT THIS TREND. NO OTHER NOTABLE CHANGES AT THIS TIME.
AS OF 240 AM EDT WEDNESDAY...
OVERALL HOT AND HUMID WEATHER FOR EARLY SEPTEMBER TO PERSIST TODAY AS
SURFACE HIGH PRESSURE REMAINS IN PLACE ACROSS THE MOUNTAINS. HOWEVER
SHORTWAVE ENERGY IN THE FORM OF AN OPENING UPPER LOW ACROSS THE OHIO
VALLEY WILL RIDE SOUTHEAST THROUGH THE 5H RIDGE AND OVER THE NORTHERN
HALF OF THE AREA THIS AFTERNOON. THIS SHOULD RESULT IN BETTER LIFT
ESPCLY ALONG AND JUST SOUTH OF THE INTERSTATE 64 CORRIDOR EARLY ON AND
ACROSS THE EASTERN HALF THROUGH LATE IN THE DAY. LATEST GUIDANCE ALSO
SHOWING BETTER INSTABILITY WITH A LITTLE MORE COOLING ALOFT...BUT STILL
UNCERTAINTY WITH COVERAGE GIVEN OVERALL BROAD SUBSIDENCE IN PLACE UNDER
RATHER WARM 5H TEMPS. CURRENT SPC/RNK WRF SOLUTIONS ALONG WITH THE
LATEST HRRR REMAIN THE MOST WIDESPREAD WITH SHRA/TSRA NORTH HALF AND
ALONG THE BLUE RIDGE. THIS WHILE MOST OTHER SOLUTIONS INCLUDING
ENSEMBLES PRODUCING LESS INCLUDING ONLY WIDELY SCATTERED SHALLOW
CONVECTION MAINLY CONFINED FROM THE VIRGINIA HIGHLANDS EAST TO AROUND
KLYH FOR THE MOST PART. THEREFORE ALIGNED HIGHEST CHANCE POPS ACROSS
THE FAR NORTH WITH A PERIOD OF LOWER CHANCES SOUTH/EAST DURING MID/LATE
AFTERNOON AND ONLY ISOLATED COVERAGE FAR SW. GIVEN WEAK FLOW ALOFT NOT
EXPECTING MUCH OF A SEVERE THREAT BUT COULD SEE A BIT MORE CLUSTERING
OF SLOW MOVING CONVECTION RIGHT NEAR THE CORE OF THE UPPER WAVE LATE.
OTHERWISE LOOKING AT MAINLY PC WITH MID DECK EARLY...THEN MORE CU THIS
AFTERNOON WITH HIGHS AGAIN REACHING THE LOW 90S EAST AND WELL INTO THE
80S ELSEWHERE PENDING TIMING OF CONVECTIVE INITIATION.
IMPULSE PASSES THIS EVENING LEAVING THE REGION IN BETWEEN WAVES AND
UNDER SURFACE HIGH PRESSURE. THIS SHOULD ALLOW MOST CONVECTION TO FADE
BY MIDNIGHT GIVEN LOSS OF HEATING AND SOME OVERNIGHT CLEARING PER WEAK
NW FLOW ALOFT IN THE WAKE OF THE MID LEVEL SYSTEM. THUS KEEPING SOME
LOW END CHANCE POPS GOING MAINLY EAST THIS EVENING BEFORE TRENDING DRY
WITH FOG AGAIN OVERNIGHT. LOWS PERHAPS SLIGHTLY COOLER GIVEN SOME DROP
IN DEWPOINTS AND ESPCLY WHERE ANY COOLING EVENING RAINFALL OCCURS BUT
STILL MOSTLY LOW/MID 60S MOUNTAINS TO UPPER 60S EAST.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
AS OF 415 AM EDT WEDNESDAY...
WEAK UPPER-LEVEL SHORT WAVE WILL BE DISSIPATING ACROSS NORTH
CAROLINA DRIFTING SLOWLY INTO THE SOUTHEAST STATES WHERE IT
APPEARS IT IS DESTINED TO BECOME A WEAK CUTOFF THAT WILL
RETROGRADE/LINGER ACROSS THE SOUTHEAST/MID-SOUTH INTO NEXT WEEK AS
A LARGE HIGH AMPLITUDE UPPER RIDGE CONTINUES TO BUILD FROM THE
SOUTH CENTRAL/CENTRAL U.S. INTO SOUTHEAST CANADA AND THE NORTHEAST
U.S. OVER THE TOP OF THE WEAK CUTOFF LOW. UPPER SUPPORT WILL BE
MINIMAL AT BEST WITH BEST DYNAMICS...WHAT THEY ARE...HAVING
DRIFTED SOUTH OF THE AREA. ANY CONVECTION WILL LARGELY BE THE
RESULT OF DIFFERENTIAL HEATING AND FOCUSED PRIMARILY ACROSS THE
WESTERN MOUNTAINS. REALLY CANNOT SUPPORT MUCH MORE THAN 30 POPS AT
BEST.
BY FRIDAY...A LARGE SURFACE HIGH DEVELOPING ACROSS THE NORTHEAST
U.S. UNDERNEATH THE MAMMOTH UPPER RIDGE WILL BEGIN TO PUSH A
BACKDOOR FRONT FROM THE MID-ATLANTIC SOUTHWESTWARD. UPPER DYNAMICS
ARE VERY WEAK...BUT A MARKED DEWPOINT GRADIENT WILL EXIST ALONG
THE SOUTHWESTWARD ADVANCING BOUNDARY AS VERY DRY AIR ADVECTS
SOUTHWEST INTO NORTHERN VA. THIS SHOULD BE SUFFICIENT TO SUPPORT
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS...WITH THE BEST
COVERAGE SHIFTING SOUTHWEST TOWARD EVENING. INSTABILITY IS QUITE
NOTABLE ACROSS THE REGION IN ADVANCE OF THIS BACKDOOR FRONT...SO
EVEN WITH WEAK DYNAMICS...WITH THE NOTED INSTABILITY AND PWATS IN
THE 1.5 TO 1.7 INCH RANGE...30-40 PERCENT POPS SEEMS REASONABLE.
FOR SATURDAY...THE BACKDOOR FRONT CONTINUES TO DRIFT SOUTHWEST AND
SHOULD BE LOCATED FROM CENTRAL WV THROUGH SOUTHWEST VA...NEAR THE
I-77 CORRIDOR...INTO CENTRAL NC. VERY DRY AIR IS NOTED ADVECTING
INTO THE REGION FROM THE NORTHEAST WITH DEWPOINTS DROPPING INTO
THE 50S AND PWATS FALLING TO NEAR 0.50 INCH ACROSS THE NORTHEAST
PART OF THE CWA. ANY CONVECTION SATURDAY SHOULD BE LIMITED TO THE
I-77 CORRIDOR AND POINTS WESTWARD...PRIMARILY DURING THE
AFTERNOON/EVENING.
TEMPERATURES WILL REMAIN WELL ABOVE NORMAL THURSDAY AND FRIDAY
AHEAD OF THE BACKDOOR FRONT...WITH MAX TEMPS WELL INTO THE
80S...NEAR 90 ACROSS THE PIEDMONT. MIN TEMPS WILL HOLD MOSTLY IN
THE 60S TO EVEN NEAR 70 ACROSS THE PIEDMONT. THESE READINGS ARE
AROUND 5 AND 10 DEGREES ABOVE NORMAL...RESPECTIVELY. MOS GUIDANCE
HAS BEEN TRENDING TOO MUCH TOWARD CLIMATOLOGY...SO NEEDED TO NUDGE
UP MOST AREAS FROM 2-3 DEGREES TO BETTER MATCH WHAT HAS BEEN
OCCURRING RECENTLY.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 445 AM EDT WEDNESDAY...
THE FOCUS THROUGH THE PERIOD WILL BE ON THE AFOREMENTIONED WEAK
AND INCREASING BROAD UPPER LOW ANCHORED ACROSS THE SOUTHEAST/MID-
SOUTH PART OF THE U.S. OUR CWA WILL BE STUCK IN THE TRANSITION
ZONE BETWEEN THIS INCREASINGLY MOIST/UNSTABLE AIR MASS TO THE
SOUTH AND THE PERSISTING UPPER RIDGE AND ASSOCIATED
SUBSIDENCE/VERY DRY AND WARM AIR MASS ACROSS THE MID-ATLANTIC
REGION. SHOWER/THUNDERSTORM CHANCES WILL GRADUALLY CREEP NORTHWARD
THROUGH THE PERIOD...BUT LIKELY REMAIN CONFINED TO AREAS WEST OF
I-77 SUNDAY...THEN CREEP FURTHER NORTH TOWARD THE U.S. 460
CORRIDOR BY MONDAY AND MUCH OF THE CWA BY TUESDAY. THE BEST
CHANCES THROUGHOUT THE PERIOD WILL REMAIN ACROSS THE WESTERN NC
MOUNTAINS. THE MODELS HAVE CONTINUALLY DELAYED THE ARRIVAL OF A
FRONT TOWARD THE MID PART OF NEXT WEEK...AND WITH THE UPPER RIDGE
SANDWICHED IN BETWEEN THE LOW PRESSURE AREA TO THE SOUTH AND THE
STRONGER WESTERLIES ALONG THE CANADIAN BORDER...IT MAY BE SOME
TIME BEFORE IT ACTUALLY REACHES OUR AREA. HENCE...SUMMER APPEARS
DESTINED TO HANG ON MUCH OF NEXT WEEK.
MAX TEMPS SHOULD BE NEAR NORMAL AT THE BEGINNING OF THE
PERIOD...BUT PERHAPS STILL SLIGHTLY ABOVE NORMAL WEST OF I-77. MIN
TEMPS WILL REMAIN NEAR NORMAL TO SLIGHTLY ABOVE NORMAL FAR
SOUTHWEST. MAX AND MIN TEMPS WILL CREEP TO SLIGHTLY ABOVE NORMAL
LEVELS AGAIN AS WE MOVE INTO EARLY NEXT WEEK.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 640 AM EDT WEDNESDAY...
FOG AND STRATUS REMAIN SPOTTY ACROSS THE REGION EARLY THIS MORNING
WITH THE TYPICAL VALLEY LOCATIONS SUCH AS KLWB/KBCB SEEING IFR OR
WORSE ATTM. EXPECT COULD SEE A BRIEF REDUCTION IN VSBY AS WELL
AROUND KLYH/KDAN AS WELL DURING THE NEXT HOUR OR TWO BEFORE
HEATING HELPS DISSIPATE ANY RESIDUAL LOW LEVEL MOISTURE. OTHERWISE
WAVES OF MID/HIGH CLOUDS AHEAD OF THE UPPER SYSTEM TO THE NW THE
MAIN ASPECT ONCE ANY LOW CLOUDS BURN OFF WITH VFR EXPECTED AT ALL
LOCATIONS FROM MID MORNING ONWARD.
UPPER WAVE OVER THE OHIO VALLEY WILL SHIFT SLOWLY SOUTHEAST INTO
VIRGINIA THIS AFTERNOON WHILE SLOWLY WEAKENING. THIS WILL ALLOW
MORE INSTABILITY WITH STEEPER LAPSE RATES AND LIFT. SHOWERS AND
STORMS WILL BE MORE SCATTERED THIS AFTERNOON WITH BEST FORCING
ACROSS THE NORTHERN FOOTHILLS/PIEDMONT TO THE NEW RIVER VALLEY.
AS OF NOW WILL KEEP THE GOING VCTS AT KROA/KLYH AND KBCB AFTER
19-20ZZ/3-4PM...BUT THINK COVERAGE WILL BE LESS FURTHER WEST AND
OVER THE SOUTHEAST...SO ONLY GOING WITH A VCSH AT KLWB-KBLF WHILE
KEEPING MENTION OUT OF KDAN FOR NOW. OVERALL EXPECT VFR
CONDITIONS OUTSIDE ANY CONVECTION INTO THIS EVENING WITH CIGS OF
4-6KFT WITH TCU AND CB IN THE AFTERNOON.
EXTENDED AVIATION DISCUSSION...
THE FORECAST AREA WILL REMAIN IN A WEAKLY FORCED SYNOPTIC
ENVIRONMENT THROUGH THURSDAY...WITH CHANCES FOR DIURNAL
CONVECTION MAINLY FROM THE BLUE RIDGE WEST...AND SOME MVFR/IFR
FOG/STRATUS DEVELOPMENT AT NIGHT...ESPECIALLY AT KBCB AND KLWB. A
WEAK BACKDOOR COOL FRONT MAY ENHANCE THE CHANCES FOR SHOWERS AND
STORMS LATER FRIDAY BEFORE DRIER AIR ARRIVES FRIDAY NIGHT.
FOR SATURDAY INTO SUNDAY WILL SEE HIGH PRESSURE IN CONTROL THOUGH
THE POSITION OF THE HIGH OVER THE MID ATLANTIC MAY SLIDE MORE MVFR
CIGS OFF THE ATLANTIC INTO OUR EASTERN TAF LOCATIONS AT LEAST TO
START THE WEEKEND.
&&
.EQUIPMENT...
AS OF 400 PM EDT TUESDAY...
THE DEW POINT READING AT KJFZ...RICHLANDS VA AWOS...IS INCORRECT.
AT THIS TIME WE DO NOT KNOW WHEN THIS SENSOR WILL BE REPAIRED.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/NF
NEAR TERM...DS/JH
SHORT TERM...RAB
LONG TERM...AMS/RAB
AVIATION...JH/NF/WP
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
940 AM EDT WED SEP 2 2015
.SYNOPSIS...
A RIDGE OF HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH THE
END OF THE WEEK. UPPER LEVEL DISTURBANCES TRACKING THROUGH THE
RIDGING WILL RESULT IN WIDELY SCATTERED MAINLY DIURNAL SHOWERS
AND STORMS INTO FRIDAY. A WEAK BACKDOOR COLD FRONT WILL DROP
SOUTH THROUGH THE AREA BY THE END OF WEEK BRINGING SOMEWHAT DRIER
AND COOLER AIR FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 AM EDT WEDNESDAY...
EARLY MORNING FOG HAS DISSIPATED IN ALL BUT PARTS OF THE
GREENBRIER AND NEW RIVER VALLEY REGIONS. HOWEVER...BY 1100 AM...AT
VAST MAJORITY...IF NOT ALL...OF THIS FOG WILL HAVE DISSIPATED AS
WELL. PRECIPITATION COVERAGE ACROSS THE REGION CURRENTLY IS ZERO.
THERE WERE A FEW ISOLATED SHOWERS OVER BUCKINGHAM COUNTY AROUND
THE TOP THE HOUR..BUT THESE HAVE SINCE FADED. LATEST MESOSCALE
MODELS PAINTS VERY LITTLE IF ANY PRECIPITATION ACROSS THE
NORTHERN PARTS OF THE AREA THROUGH 17Z/1PM...AND THEN START
RAMPING UP THE COVERAGE AFTER THAT TIME. HAVE TWEAKED THE
PROBABILITY OF PRECIPITATION GRIDS AND THE WEATHER GRIDS TO BETTER
REFLECT THIS TREND. NO OTHER NOTABLE CHANGES AT THIS TIME.
AS OF 240 AM EDT WEDNESDAY...
OVERALL HOT AND HUMID WEATHER FOR EARLY SEPTEMBER TO PERSIST TODAY AS
SURFACE HIGH PRESSURE REMAINS IN PLACE ACROSS THE MOUNTAINS. HOWEVER
SHORTWAVE ENERGY IN THE FORM OF AN OPENING UPPER LOW ACROSS THE OHIO
VALLEY WILL RIDE SOUTHEAST THROUGH THE 5H RIDGE AND OVER THE NORTHERN
HALF OF THE AREA THIS AFTERNOON. THIS SHOULD RESULT IN BETTER LIFT
ESPCLY ALONG AND JUST SOUTH OF THE INTERSTATE 64 CORRIDOR EARLY ON AND
ACROSS THE EASTERN HALF THROUGH LATE IN THE DAY. LATEST GUIDANCE ALSO
SHOWING BETTER INSTABILITY WITH A LITTLE MORE COOLING ALOFT...BUT STILL
UNCERTAINTY WITH COVERAGE GIVEN OVERALL BROAD SUBSIDENCE IN PLACE UNDER
RATHER WARM 5H TEMPS. CURRENT SPC/RNK WRF SOLUTIONS ALONG WITH THE
LATEST HRRR REMAIN THE MOST WIDESPREAD WITH SHRA/TSRA NORTH HALF AND
ALONG THE BLUE RIDGE. THIS WHILE MOST OTHER SOLUTIONS INCLUDING
ENSEMBLES PRODUCING LESS INCLUDING ONLY WIDELY SCATTERED SHALLOW
CONVECTION MAINLY CONFINED FROM THE VIRGINIA HIGHLANDS EAST TO AROUND
KLYH FOR THE MOST PART. THEREFORE ALIGNED HIGHEST CHANCE POPS ACROSS
THE FAR NORTH WITH A PERIOD OF LOWER CHANCES SOUTH/EAST DURING MID/LATE
AFTERNOON AND ONLY ISOLATED COVERAGE FAR SW. GIVEN WEAK FLOW ALOFT NOT
EXPECTING MUCH OF A SEVERE THREAT BUT COULD SEE A BIT MORE CLUSTERING
OF SLOW MOVING CONVECTION RIGHT NEAR THE CORE OF THE UPPER WAVE LATE.
OTHERWISE LOOKING AT MAINLY PC WITH MID DECK EARLY...THEN MORE CU THIS
AFTERNOON WITH HIGHS AGAIN REACHING THE LOW 90S EAST AND WELL INTO THE
80S ELSEWHERE PENDING TIMING OF CONVECTIVE INITIATION.
IMPULSE PASSES THIS EVENING LEAVING THE REGION IN BETWEEN WAVES AND
UNDER SURFACE HIGH PRESSURE. THIS SHOULD ALLOW MOST CONVECTION TO FADE
BY MIDNIGHT GIVEN LOSS OF HEATING AND SOME OVERNIGHT CLEARING PER WEAK
NW FLOW ALOFT IN THE WAKE OF THE MID LEVEL SYSTEM. THUS KEEPING SOME
LOW END CHANCE POPS GOING MAINLY EAST THIS EVENING BEFORE TRENDING DRY
WITH FOG AGAIN OVERNIGHT. LOWS PERHAPS SLIGHTLY COOLER GIVEN SOME DROP
IN DEWPOINTS AND ESPCLY WHERE ANY COOLING EVENING RAINFALL OCCURS BUT
STILL MOSTLY LOW/MID 60S MOUNTAINS TO UPPER 60S EAST.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
AS OF 415 AM EDT WEDNESDAY...
WEAK UPPER-LEVEL SHORT WAVE WILL BE DISSIPATING ACROSS NORTH
CAROLINA DRIFTING SLOWLY INTO THE SOUTHEAST STATES WHERE IT
APPEARS IT IS DESTINED TO BECOME A WEAK CUTOFF THAT WILL
RETROGRADE/LINGER ACROSS THE SOUTHEAST/MID-SOUTH INTO NEXT WEEK AS
A LARGE HIGH AMPLITUDE UPPER RIDGE CONTINUES TO BUILD FROM THE
SOUTH CENTRAL/CENTRAL U.S. INTO SOUTHEAST CANADA AND THE NORTHEAST
U.S. OVER THE TOP OF THE WEAK CUTOFF LOW. UPPER SUPPORT WILL BE
MINIMAL AT BEST WITH BEST DYNAMICS...WHAT THEY ARE...HAVING
DRIFTED SOUTH OF THE AREA. ANY CONVECTION WILL LARGELY BE THE
RESULT OF DIFFERENTIAL HEATING AND FOCUSED PRIMARILY ACROSS THE
WESTERN MOUNTAINS. REALLY CANNOT SUPPORT MUCH MORE THAN 30 POPS AT
BEST.
BY FRIDAY...A LARGE SURFACE HIGH DEVELOPING ACROSS THE NORTHEAST
U.S. UNDERNEATH THE MAMMOTH UPPER RIDGE WILL BEGIN TO PUSH A
BACKDOOR FRONT FROM THE MID-ATLANTIC SOUTHWESTWARD. UPPER DYNAMICS
ARE VERY WEAK...BUT A MARKED DEWPOINT GRADIENT WILL EXIST ALONG
THE SOUTHWESTWARD ADVANCING BOUNDARY AS VERY DRY AIR ADVECTS
SOUTHWEST INTO NORTHERN VA. THIS SHOULD BE SUFFICIENT TO SUPPORT
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS...WITH THE BEST
COVERAGE SHIFTING SOUTHWEST TOWARD EVENING. INSTABILITY IS QUITE
NOTABLE ACROSS THE REGION IN ADVANCE OF THIS BACKDOOR FRONT...SO
EVEN WITH WEAK DYNAMICS...WITH THE NOTED INSTABILITY AND PWATS IN
THE 1.5 TO 1.7 INCH RANGE...30-40 PERCENT POPS SEEMS REASONABLE.
FOR SATURDAY...THE BACKDOOR FRONT CONTINUES TO DRIFT SOUTHWEST AND
SHOULD BE LOCATED FROM CENTRAL WV THROUGH SOUTHWEST VA...NEAR THE
I-77 CORRIDOR...INTO CENTRAL NC. VERY DRY AIR IS NOTED ADVECTING
INTO THE REGION FROM THE NORTHEAST WITH DEWPOINTS DROPPING INTO
THE 50S AND PWATS FALLING TO NEAR 0.50 INCH ACROSS THE NORTHEAST
PART OF THE CWA. ANY CONVECTION SATURDAY SHOULD BE LIMITED TO THE
I-77 CORRIDOR AND POINTS WESTWARD...PRIMARILY DURING THE
AFTERNOON/EVENING.
TEMPERATURES WILL REMAIN WELL ABOVE NORMAL THURSDAY AND FRIDAY
AHEAD OF THE BACKDOOR FRONT...WITH MAX TEMPS WELL INTO THE
80S...NEAR 90 ACROSS THE PIEDMONT. MIN TEMPS WILL HOLD MOSTLY IN
THE 60S TO EVEN NEAR 70 ACROSS THE PIEDMONT. THESE READINGS ARE
AROUND 5 AND 10 DEGREES ABOVE NORMAL...RESPECTIVELY. MOS GUIDANCE
HAS BEEN TRENDING TOO MUCH TOWARD CLIMATOLOGY...SO NEEDED TO NUDGE
UP MOST AREAS FROM 2-3 DEGREES TO BETTER MATCH WHAT HAS BEEN
OCCURRING RECENTLY.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 445 AM EDT WEDNESDAY...
THE FOCUS THROUGH THE PERIOD WILL BE ON THE AFOREMENTIONED WEAK
AND INCREASING BROAD UPPER LOW ANCHORED ACROSS THE SOUTHEAST/MID-
SOUTH PART OF THE U.S. OUR CWA WILL BE STUCK IN THE TRANSITION
ZONE BETWEEN THIS INCREASINGLY MOIST/UNSTABLE AIR MASS TO THE
SOUTH AND THE PERSISTING UPPER RIDGE AND ASSOCIATED
SUBSIDENCE/VERY DRY AND WARM AIR MASS ACROSS THE MID-ATLANTIC
REGION. SHOWER/THUNDERSTORM CHANCES WILL GRADUALLY CREEP NORTHWARD
THROUGH THE PERIOD...BUT LIKELY REMAIN CONFINED TO AREAS WEST OF
I-77 SUNDAY...THEN CREEP FURTHER NORTH TOWARD THE U.S. 460
CORRIDOR BY MONDAY AND MUCH OF THE CWA BY TUESDAY. THE BEST
CHANCES THROUGHOUT THE PERIOD WILL REMAIN ACROSS THE WESTERN NC
MOUNTAINS. THE MODELS HAVE CONTINUALLY DELAYED THE ARRIVAL OF A
FRONT TOWARD THE MID PART OF NEXT WEEK...AND WITH THE UPPER RIDGE
SANDWICHED IN BETWEEN THE LOW PRESSURE AREA TO THE SOUTH AND THE
STRONGER WESTERLIES ALONG THE CANADIAN BORDER...IT MAY BE SOME
TIME BEFORE IT ACTUALLY REACHES OUR AREA. HENCE...SUMMER APPEARS
DESTINED TO HANG ON MUCH OF NEXT WEEK.
MAX TEMPS SHOULD BE NEAR NORMAL AT THE BEGINNING OF THE
PERIOD...BUT PERHAPS STILL SLIGHTLY ABOVE NORMAL WEST OF I-77. MIN
TEMPS WILL REMAIN NEAR NORMAL TO SLIGHTLY ABOVE NORMAL FAR
SOUTHWEST. MAX AND MIN TEMPS WILL CREEP TO SLIGHTLY ABOVE NORMAL
LEVELS AGAIN AS WE MOVE INTO EARLY NEXT WEEK.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
AS OF 640 AM EDT WEDNESDAY...
FOG AND STRATUS REMAIN SPOTTY ACROSS THE REGION EARLY THIS MORNING
WITH THE TYPICAL VALLEY LOCATIONS SUCH AS KLWB/KBCB SEEING IFR OR
WORSE ATTM. EXPECT COULD SEE A BRIEF REDUCTION IN VSBY AS WELL
AROUND KLYH/KDAN AS WELL DURING THE NEXT HOUR OR TWO BEFORE
HEATING HELPS DISSIPATE ANY RESIDUAL LOW LEVEL MOISTURE. OTHERWISE
WAVES OF MID/HIGH CLOUDS AHEAD OF THE UPPER SYSTEM TO THE NW THE
MAIN ASPECT ONCE ANY LOW CLOUDS BURN OFF WITH VFR EXPECTED AT ALL
LOCATIONS FROM MID MORNING ONWARD.
UPPER WAVE OVER THE OHIO VALLEY WILL SHIFT SLOWLY SOUTHEAST INTO
VIRGINIA THIS AFTERNOON WHILE SLOWLY WEAKENING. THIS WILL ALLOW
MORE INSTABILITY WITH STEEPER LAPSE RATES AND LIFT. SHOWERS AND
STORMS WILL BE MORE SCATTERED THIS AFTERNOON WITH BEST FORCING
ACROSS THE NORTHERN FOOTHILLS/PIEDMONT TO THE NEW RIVER VALLEY.
AS OF NOW WILL KEEP THE GOING VCTS AT KROA/KLYH AND KBCB AFTER
19-20ZZ/3-4PM...BUT THINK COVERAGE WILL BE LESS FURTHER WEST AND
OVER THE SOUTHEAST...SO ONLY GOING WITH A VCSH AT KLWB-KBLF WHILE
KEEPING MENTION OUT OF KDAN FOR NOW. OVERALL EXPECT VFR
CONDITIONS OUTSIDE ANY CONVECTION INTO THIS EVENING WITH CIGS OF
4-6KFT WITH TCU AND CB IN THE AFTERNOON.
EXTENDED AVIATION DISCUSSION...
THE FORECAST AREA WILL REMAIN IN A WEAKLY FORCED SYNOPTIC
ENVIRONMENT THROUGH THURSDAY...WITH CHANCES FOR DIURNAL
CONVECTION MAINLY FROM THE BLUE RIDGE WEST...AND SOME MVFR/IFR
FOG/STRATUS DEVELOPMENT AT NIGHT...ESPECIALLY AT KBCB AND KLWB. A
WEAK BACKDOOR COOL FRONT MAY ENHANCE THE CHANCES FOR SHOWERS AND
STORMS LATER FRIDAY BEFORE DRIER AIR ARRIVES FRIDAY NIGHT.
FOR SATURDAY INTO SUNDAY WILL SEE HIGH PRESSURE IN CONTROL THOUGH
THE POSITION OF THE HIGH OVER THE MID ATLANTIC MAY SLIDE MORE MVFR
CIGS OFF THE ATLANTIC INTO OUR EASTERN TAF LOCATIONS AT LEAST TO
START THE WEEKEND.
&&
.EQUIPMENT...
AS OF 400 PM EDT TUESDAY...
THE DEW POINT READING AT KJFZ...RICHLANDS VA AWOS...IS INCORRECT.
AT THIS TIME WE DO NOT KNOW WHEN THIS SENSOR WILL BE REPAIRED.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/NF
NEAR TERM...DS/JH
SHORT TERM...RAB
LONG TERM...AMS/RAB
AVIATION...JH/NF/WP
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
654 AM EDT WED SEP 2 2015
.SYNOPSIS...
A RIDGE OF HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH THE
END OF THE WEEK. UPPER LEVEL DISTURBANCES TRACKING THROUGH THE
RIDGING WILL RESULT IN WIDELY SCATTERED MAINLY DIURNAL SHOWERS
AND STORMS INTO FRIDAY. A WEAK BACKDOOR COLD FRONT WILL DROP
SOUTH THROUGH THE AREA BY THE END OF WEEK BRINGING SOMEWHAT DRIER
AND COOLER AIR FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 240 AM EDT WEDNESDAY...
OVERALL HOT AND HUMID WEATHER FOR EARLY SEPTEMBER TO PERSIST TODAY AS
SURFACE HIGH PRESSURE REMAINS IN PLACE ACROSS THE MOUNTAINS. HOWEVER
SHORTWAVE ENERGY IN THE FORM OF AN OPENING UPPER LOW ACROSS THE OHIO
VALLEY WILL RIDE SOUTHEAST THROUGH THE 5H RIDGE AND OVER THE NORTHERN
HALF OF THE AREA THIS AFTERNOON. THIS SHOULD RESULT IN BETTER LIFT
ESPCLY ALONG AND JUST SOUTH OF THE INTERSTATE 64 CORRIDOR EARLY ON AND
ACROSS THE EASTERN HALF THROUGH LATE IN THE DAY. LATEST GUIDANCE ALSO
SHOWING BETTER INSTABILITY WITH A LITTLE MORE COOLING ALOFT...BUT STILL
UNCERTAINTY WITH COVERAGE GIVEN OVERALL BROAD SUBSIDENCE IN PLACE UNDER
RATHER WARM 5H TEMPS. CURRENT SPC/RNK WRF SOLUTIONS ALONG WITH THE
LATEST HRRR REMAIN THE MOST WIDESPREAD WITH SHRA/TSRA NORTH HALF AND
ALONG THE BLUE RIDGE. THIS WHILE MOST OTHER SOLUTIONS INCLUDING
ENSEMBLES PRODUCING LESS INCLUDING ONLY WIDELY SCATTERED SHALLOW
CONVECTION MAINLY CONFINED FROM THE VIRGINIA HIGHLANDS EAST TO AROUND
KLYH FOR THE MOST PART. THEREFORE ALIGNED HIGHEST CHANCE POPS ACROSS
THE FAR NORTH WITH A PERIOD OF LOWER CHANCES SOUTH/EAST DURING MID/LATE
AFTERNOON AND ONLY ISOLATED COVERAGE FAR SW. GIVEN WEAK FLOW ALOFT NOT
EXPECTING MUCH OF A SEVERE THREAT BUT COULD SEE A BIT MORE CLUSTERING
OF SLOW MOVING CONVECTION RIGHT NEAR THE CORE OF THE UPPER WAVE LATE.
OTHERWISE LOOKING AT MAINLY PC WITH MID DECK EARLY...THEN MORE CU THIS
AFTERNOON WITH HIGHS AGAIN REACHING THE LOW 90S EAST AND WELL INTO THE
80S ELSEWHERE PENDING TIMING OF CONVECTIVE INITIATION.
IMPULSE PASSES THIS EVENING LEAVING THE REGION IN BETWEEN WAVES AND
UNDER SURFACE HIGH PRESSURE. THIS SHOULD ALLOW MOST CONVECTION TO FADE
BY MIDNIGHT GIVEN LOSS OF HEATING AND SOME OVERNIGHT CLEARING PER WEAK
NW FLOW ALOFT IN THE WAKE OF THE MID LEVEL SYSTEM. THUS KEEPING SOME
LOW END CHANCE POPS GOING MAINLY EAST THIS EVENING BEFORE TRENDING DRY
WITH FOG AGAIN OVERNIGHT. LOWS PERHAPS SLIGHTLY COOLER GIVEN SOME DROP
IN DEWPOINTS AND ESPCLY WHERE ANY COOLING EVENING RAINFALL OCCURS BUT
STILL MOSTLY LOW/MID 60S MOUNTAINS TO UPPER 60S EAST.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
AS OF 415 AM EDT WEDNESDAY...
WEAK UPPER-LEVEL SHORT WAVE WILL BE DISSIPATING ACROSS NORTH
CAROLINA DRIFTING SLOWLY INTO THE SOUTHEAST STATES WHERE IT
APPEARS IT IS DESTINED TO BECOME A WEAK CUTOFF THAT WILL
RETROGRADE/LINGER ACROSS THE SOUTHEAST/MID-SOUTH INTO NEXT WEEK AS
A LARGE HIGH AMPLITUDE UPPER RIDGE CONTINUES TO BUILD FROM THE
SOUTH CENTRAL/CENTRAL U.S. INTO SOUTHEAST CANADA AND THE NORTHEAST
U.S. OVER THE TOP OF THE WEAK CUTOFF LOW. UPPER SUPPORT WILL BE
MINIMAL AT BEST WITH BEST DYNAMICS...WHAT THEY ARE...HAVING
DRIFTED SOUTH OF THE AREA. ANY CONVECTION WILL LARGELY BE THE
RESULT OF DIFFERENTIAL HEATING AND FOCUSED PRIMARILY ACROSS THE
WESTERN MOUNTAINS. REALLY CANNOT SUPPORT MUCH MORE THAN 30 POPS AT
BEST.
BY FRIDAY...A LARGE SURFACE HIGH DEVELOPING ACROSS THE NORTHEAST
U.S. UNDERNEATH THE MAMMOTH UPPER RIDGE WILL BEGIN TO PUSH A
BACKDOOR FRONT FROM THE MID-ATLANTIC SOUTHWESTWARD. UPPER DYNAMICS
ARE VERY WEAK...BUT A MARKED DEWPOINT GRADIENT WILL EXIST ALONG
THE SOUTHWESTWARD ADVANCING BOUNDARY AS VERY DRY AIR ADVECTS
SOUTHWEST INTO NORTHERN VA. THIS SHOULD BE SUFFICIENT TO SUPPORT
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS...WITH THE BEST
COVERAGE SHIFTING SOUTHWEST TOWARD EVENING. INSTABILITY IS QUITE
NOTABLE ACROSS THE REGION IN ADVANCE OF THIS BACKDOOR FRONT...SO
EVEN WITH WEAK DYNAMICS...WITH THE NOTED INSTABILITY AND PWATS IN
THE 1.5 TO 1.7 INCH RANGE...30-40 PERCENT POPS SEEMS REASONABLE.
FOR SATURDAY...THE BACKDOOR FRONT CONTINUES TO DRIFT SOUTHWEST AND
SHOULD BE LOCATED FROM CENTRAL WV THROUGH SOUTHWEST VA...NEAR THE
I-77 CORRIDOR...INTO CENTRAL NC. VERY DRY AIR IS NOTED ADVECTING
INTO THE REGION FROM THE NORTHEAST WITH DEWPOINTS DROPPING INTO
THE 50S AND PWATS FALLING TO NEAR 0.50 INCH ACROSS THE NORTHEAST
PART OF THE CWA. ANY CONVECTION SATURDAY SHOULD BE LIMITED TO THE
I-77 CORRIDOR AND POINTS WESTWARD...PRIMARILY DURING THE
AFTERNOON/EVENING.
TEMPERATURES WILL REMAIN WELL ABOVE NORMAL THURSDAY AND FRIDAY
AHEAD OF THE BACKDOOR FRONT...WITH MAX TEMPS WELL INTO THE
80S...NEAR 90 ACROSS THE PIEDMONT. MIN TEMPS WILL HOLD MOSTLY IN
THE 60S TO EVEN NEAR 70 ACROSS THE PIEDMONT. THESE READINGS ARE
AROUND 5 AND 10 DEGREES ABOVE NORMAL...RESPECTIVELY. MOS GUIDANCE
HAS BEEN TRENDING TOO MUCH TOWARD CLIMATOLOGY...SO NEEDED TO NUDGE
UP MOST AREAS FROM 2-3 DEGREES TO BETTER MATCH WHAT HAS BEEN
OCCURRING RECENTLY.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 445 AM EDT WEDNESDAY...
THE FOCUS THROUGH THE PERIOD WILL BE ON THE AFOREMENTIONED WEAK
AND INCREASING BROAD UPPER LOW ANCHORED ACROSS THE SOUTHEAST/MID-
SOUTH PART OF THE U.S. OUR CWA WILL BE STUCK IN THE TRANSITION
ZONE BETWEEN THIS INCREASINGLY MOIST/UNSTABLE AIR MASS TO THE
SOUTH AND THE PERSISTING UPPER RIDGE AND ASSOCIATED
SUBSIDENCE/VERY DRY AND WARM AIR MASS ACROSS THE MID-ATLANTIC
REGION. SHOWER/THUNDERSTORM CHANCES WILL GRADUALLY CREEP NORTHWARD
THROUGH THE PERIOD...BUT LIKELY REMAIN CONFINED TO AREAS WEST OF
I-77 SUNDAY...THEN CREEP FURTHER NORTH TOWARD THE U.S. 460
CORRIDOR BY MONDAY AND MUCH OF THE CWA BY TUESDAY. THE BEST
CHANCES THROUGHOUT THE PERIOD WILL REMAIN ACROSS THE WESTERN NC
MOUNTAINS. THE MODELS HAVE CONTINUALLY DELAYED THE ARRIVAL OF A
FRONT TOWARD THE MID PART OF NEXT WEEK...AND WITH THE UPPER RIDGE
SANDWICHED IN BETWEEN THE LOW PRESSURE AREA TO THE SOUTH AND THE
STRONGER WESTERLIES ALONG THE CANADIAN BORDER...IT MAY BE SOME
TIME BEFORE IT ACTUALLY REACHES OUR AREA. HENCE...SUMMER APPEARS
DESTINED TO HANG ON MUCH OF NEXT WEEK.
MAX TEMPS SHOULD BE NEAR NORMAL AT THE BEGINNING OF THE
PERIOD...BUT PERHAPS STILL SLIGHTLY ABOVE NORMAL WEST OF I-77. MIN
TEMPS WILL REMAIN NEAR NORMAL TO SLIGHTLY ABOVE NORMAL FAR
SOUTHWEST. MAX AND MIN TEMPS WILL CREEP TO SLIGHTLY ABOVE NORMAL
LEVELS AGAIN AS WE MOVE INTO EARLY NEXT WEEK.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 640 AM EDT WEDNESDAY...
FOG AND STRATUS REMAIN SPOTTY ACROSS THE REGION EARLY THIS MORNING
WITH THE TYPICAL VALLEY LOCATIONS SUCH AS KLWB/KBCB SEEING IFR OR
WORSE ATTM. EXPECT COULD SEE A BRIEF REDUCTION IN VSBY AS WELL
AROUND KLYH/KDAN AS WELL DURING THE NEXT HOUR OR TWO BEFORE
HEATING HELPS DISSIPATE ANY RESIDUAL LOW LEVEL MOISTURE. OTHERWISE
WAVES OF MID/HIGH CLOUDS AHEAD OF THE UPPER SYSTEM TO THE NW THE
MAIN ASPECT ONCE ANY LOW CLOUDS BURN OFF WITH VFR EXPECTED AT ALL
LOCATIONS FROM MID MORNING ONWARD.
UPPER WAVE OVER THE OHIO VALLEY WILL SHIFT SLOWLY SOUTHEAST INTO
VIRGINIA THIS AFTERNOON WHILE SLOWLY WEAKENING. THIS WILL ALLOW
MORE INSTABILITY WITH STEEPER LAPSE RATES AND LIFT. SHOWERS AND
STORMS WILL BE MORE SCATTERED THIS AFTERNOON WITH BEST FORCING
ACROSS THE NORTHERN FOOTHILLS/PIEDMONT TO THE NEW RIVER VALLEY.
AS OF NOW WILL KEEP THE GOING VCTS AT KROA/KLYH AND KBCB AFTER
19-20ZZ/3-4PM...BUT THINK COVERAGE WILL BE LESS FURTHER WEST AND
OVER THE SOUTHEAST...SO ONLY GOING WITH A VCSH AT KLWB-KBLF WHILE
KEEPING MENTION OUT OF KDAN FOR NOW. OVERALL EXPECT VFR
CONDITIONS OUTSIDE ANY CONVECTION INTO THIS EVENING WITH CIGS OF
4-6KFT WITH TCU AND CB IN THE AFTERNOON.
EXTENDED AVIATION DISCUSSION...
THE FORECAST AREA WILL REMAIN IN A WEAKLY FORCED SYNOPTIC
ENVIRONMENT THROUGH THURSDAY...WITH CHANCES FOR DIURNAL
CONVECTION MAINLY FROM THE BLUE RIDGE WEST...AND SOME MVFR/IFR
FOG/STRATUS DEVELOPMENT AT NIGHT...ESPECIALLY AT KBCB AND KLWB. A
WEAK BACKDOOR COOL FRONT MAY ENHANCE THE CHANCES FOR SHOWERS AND
STORMS LATER FRIDAY BEFORE DRIER AIR ARRIVES FRIDAY NIGHT.
FOR SATURDAY INTO SUNDAY WILL SEE HIGH PRESSURE IN CONTROL THOUGH
THE POSITION OF THE HIGH OVER THE MID ATLANTIC MAY SLIDE MORE MVFR
CIGS OFF THE ATLANTIC INTO OUR EASTERN TAF LOCATIONS AT LEAST TO
START THE WEEKEND.
&&
.EQUIPMENT...
AS OF 400 PM EDT TUESDAY...
THE DEW POINT READING AT KJFZ...RICHLANDS VA AWOS...IS INCORRECT.
AT THIS TIME WE DO NOT KNOW WHEN THIS SENSOR WILL BE REPAIRED.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/NF
NEAR TERM...JH
SHORT TERM...RAB
LONG TERM...AMS/RAB
AVIATION...JH/NF/WP
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
450 AM EDT WED SEP 2 2015
.SYNOPSIS...
A RIDGE OF HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH THE
END OF THE WEEK. UPPER LEVEL DISTURBANCES TRACKING THROUGH THE
RIDGING WILL RESULT IN WIDELY SCATTERED MAINLY DIURNAL SHOWERS
AND STORMS INTO FRIDAY. A WEAK BACKDOOR COLD FRONT WILL DROP
SOUTH THROUGH THE AREA BY THE END OF WEEK BRINGING SOMEWHAT DRIER
AND COOLER AIR FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 240 AM EDT WEDNESDAY...
OVERALL HOT AND HUMID WEATHER FOR EARLY SEPTEMBER TO PERSIST TODAY AS
SURFACE HIGH PRESSURE REMAINS IN PLACE ACROSS THE MOUNTAINS. HOWEVER
SHORTWAVE ENERGY IN THE FORM OF AN OPENING UPPER LOW ACROSS THE OHIO
VALLEY WILL RIDE SOUTHEAST THROUGH THE 5H RIDGE AND OVER THE NORTHERN
HALF OF THE AREA THIS AFTERNOON. THIS SHOULD RESULT IN BETTER LIFT
ESPCLY ALONG AND JUST SOUTH OF THE INTERSTATE 64 CORRIDOR EARLY ON AND
ACROSS THE EASTERN HALF THROUGH LATE IN THE DAY. LATEST GUIDANCE ALSO
SHOWING BETTER INSTABILITY WITH A LITTLE MORE COOLING ALOFT...BUT STILL
UNCERTAINTY WITH COVERAGE GIVEN OVERALL BROAD SUBSIDENCE IN PLACE UNDER
RATHER WARM 5H TEMPS. CURRENT SPC/RNK WRF SOLUTIONS ALONG WITH THE
LATEST HRRR REMAIN THE MOST WIDESPREAD WITH SHRA/TSRA NORTH HALF AND
ALONG THE BLUE RIDGE. THIS WHILE MOST OTHER SOLUTIONS INCLUDING
ENSEMBLES PRODUCING LESS INCLUDING ONLY WIDELY SCATTERED SHALLOW
CONVECTION MAINLY CONFINED FROM THE VIRGINIA HIGHLANDS EAST TO AROUND
KLYH FOR THE MOST PART. THEREFORE ALIGNED HIGHEST CHANCE POPS ACROSS
THE FAR NORTH WITH A PERIOD OF LOWER CHANCES SOUTH/EAST DURING MID/LATE
AFTERNOON AND ONLY ISOLATED COVERAGE FAR SW. GIVEN WEAK FLOW ALOFT NOT
EXPECTING MUCH OF A SEVERE THREAT BUT COULD SEE A BIT MORE CLUSTERING
OF SLOW MOVING CONVECTION RIGHT NEAR THE CORE OF THE UPPER WAVE LATE.
OTHERWISE LOOKING AT MAINLY PC WITH MID DECK EARLY...THEN MORE CU THIS
AFTERNOON WITH HIGHS AGAIN REACHING THE LOW 90S EAST AND WELL INTO THE
80S ELSEWHERE PENDING TIMING OF CONVECTIVE INITIATION.
IMPULSE PASSES THIS EVENING LEAVING THE REGION IN BETWEEN WAVES AND
UNDER SURFACE HIGH PRESSURE. THIS SHOULD ALLOW MOST CONVECTION TO FADE
BY MIDNIGHT GIVEN LOSS OF HEATING AND SOME OVERNIGHT CLEARING PER WEAK
NW FLOW ALOFT IN THE WAKE OF THE MID LEVEL SYSTEM. THUS KEEPING SOME
LOW END CHANCE POPS GOING MAINLY EAST THIS EVENING BEFORE TRENDING DRY
WITH FOG AGAIN OVERNIGHT. LOWS PERHAPS SLIGHTLY COOLER GIVEN SOME DROP
IN DEWPOINTS AND ESPCLY WHERE ANY COOLING EVENING RAINFALL OCCURS BUT
STILL MOSTLY LOW/MID 60S MOUNTAINS TO UPPER 60S EAST.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
AS OF 415 AM EDT WEDNESDAY...
WEAK UPPER-LEVEL SHORT WAVE WILL BE DISSIPATING ACROSS NORTH
CAROLINA DRIFTING SLOWLY INTO THE SOUTHEAST STATES WHERE IT
APPEARS IT IS DESTINED TO BECOME A WEAK CUTOFF THAT WILL
RETROGRADE/LINGER ACROSS THE SOUTHEAST/MID-SOUTH INTO NEXT WEEK AS
A LARGE HIGH AMPLITUDE UPPER RIDGE CONTINUES TO BUILD FROM THE
SOUTH CENTRAL/CENTRAL U.S. INTO SOUTHEAST CANADA AND THE NORTHEAST
U.S. OVER THE TOP OF THE WEAK CUTOFF LOW. UPPER SUPPORT WILL BE
MINIMAL AT BEST WITH BEST DYNAMICS...WHAT THEY ARE...HAVING
DRIFTED SOUTH OF THE AREA. ANY CONVECTION WILL LARGELY BE THE
RESULT OF DIFFERENTIAL HEATING AND FOCUSED PRIMARILY ACROSS THE
WESTERN MOUNTAINS. REALLY CANNOT SUPPORT MUCH MORE THAN 30 POPS AT
BEST.
BY FRIDAY...A LARGE SURFACE HIGH DEVELOPING ACROSS THE NORTHEAST
U.S. UNDERNEATH THE MAMMOTH UPPER RIDGE WILL BEGIN TO PUSH A
BACKDOOR FRONT FROM THE MID-ATLANTIC SOUTHWESTWARD. UPPER DYNAMICS
ARE VERY WEAK...BUT A MARKED DEWPOINT GRADIENT WILL EXIST ALONG
THE SOUTHWESTWARD ADVANCING BOUNDARY AS VERY DRY AIR ADVECTS
SOUTHWEST INTO NORTHERN VA. THIS SHOULD BE SUFFICIENT TO SUPPORT
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS...WITH THE BEST
COVERAGE SHIFTING SOUTHWEST TOWARD EVENING. INSTABILITY IS QUITE
NOTABLE ACROSS THE REGION IN ADVANCE OF THIS BACKDOOR FRONT...SO
EVEN WITH WEAK DYNAMICS...WITH THE NOTED INSTABILITY AND PWATS IN
THE 1.5 TO 1.7 INCH RANGE...30-40 PERCENT POPS SEEMS REASONABLE.
FOR SATURDAY...THE BACKDOOR FRONT CONTINUES TO DRIFT SOUTHWEST AND
SHOULD BE LOCATED FROM CENTRAL WV THROUGH SOUTHWEST VA...NEAR THE
I-77 CORRIDOR...INTO CENTRAL NC. VERY DRY AIR IS NOTED ADVECTING
INTO THE REGION FROM THE NORTHEAST WITH DEWPOINTS DROPPING INTO
THE 50S AND PWATS FALLING TO NEAR 0.50 INCH ACROSS THE NORTHEAST
PART OF THE CWA. ANY CONVECTION SATURDAY SHOULD BE LIMITED TO THE
I-77 CORRIDOR AND POINTS WESTWARD...PRIMARILY DURING THE
AFTERNOON/EVENING.
TEMPERATURES WILL REMAIN WELL ABOVE NORMAL THURSDAY AND FRIDAY
AHEAD OF THE BACKDOOR FRONT...WITH MAX TEMPS WELL INTO THE
80S...NEAR 90 ACROSS THE PIEDMONT. MIN TEMPS WILL HOLD MOSTLY IN
THE 60S TO EVEN NEAR 70 ACROSS THE PIEDMONT. THESE READINGS ARE
AROUND 5 AND 10 DEGREES ABOVE NORMAL...RESPECTIVELY. MOS GUIDANCE
HAS BEEN TRENDING TOO MUCH TOWARD CLIMATOLOGY...SO NEEDED TO NUDGE
UP MOST AREAS FROM 2-3 DEGREES TO BETTER MATCH WHAT HAS BEEN
OCCURRING RECENTLY.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 445 AM EDT WEDNESDAY...
THE FOCUS THROUGH THE PERIOD WILL BE ON THE AFOREMENTIONED WEAK
AND INCREASING BROAD UPPER LOW ANCHORED ACROSS THE SOUTHEAST/MID-
SOUTH PART OF THE U.S. OUR CWA WILL BE STUCK IN THE TRANSITION
ZONE BETWEEN THIS INCREASINGLY MOIST/UNSTABLE AIR MASS TO THE
SOUTH AND THE PERSISTING UPPER RIDGE AND ASSOCIATED
SUBSIDENCE/VERY DRY AND WARM AIR MASS ACROSS THE MID-ATLANTIC
REGION. SHOWER/THUNDERSTORM CHANCES WILL GRADUALLY CREEP NORTHWARD
THROUGH THE PERIOD...BUT LIKELY REMAIN CONFINED TO AREAS WEST OF
I-77 SUNDAY...THEN CREEP FURTHER NORTH TOWARD THE U.S. 460
CORRIDOR BY MONDAY AND MUCH OF THE CWA BY TUESDAY. THE BEST
CHANCES THROUGHOUT THE PERIOD WILL REMAIN ACROSS THE WESTERN NC
MOUNTAINS. THE MODELS HAVE CONTINUALLY DELAYED THE ARRIVAL OF A
FRONT TOWARD THE MID PART OF NEXT WEEK...AND WITH THE UPPER RIDGE
SANDWICHED IN BETWEEN THE LOW PRESSURE AREA TO THE SOUTH AND THE
STRONGER WESTERLIES ALONG THE CANADIAN BORDER...IT MAY BE SOME
TIME BEFORE IT ACTUALLY REACHES OUR AREA. HENCE...SUMMER APPEARS
DESTINED TO HANG ON MUCH OF NEXT WEEK.
MAX TEMPS SHOULD BE NEAR NORMAL AT THE BEGINNING OF THE
PERIOD...BUT PERHAPS STILL SLIGHTLY ABOVE NORMAL WEST OF I-77. MIN
TEMPS WILL REMAIN NEAR NORMAL TO SLIGHTLY ABOVE NORMAL FAR
SOUTHWEST. MAX AND MIN TEMPS WILL CREEP TO SLIGHTLY ABOVE NORMAL
LEVELS AGAIN AS WE MOVE INTO EARLY NEXT WEEK.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
AS OF 100 AM EDT WEDNESDAY...
OTHER THAN FOR DEBRIS MID/HIGH CLOUDS...FOG THE MAIN CONCERN
OVERNIGHT WITH POTENTIAL AGAIN GIVEN LESS CLOUDS OF SEEING THE
VALLEYS SUCH AS KLWB/KBCB DROP INTO LIFR/IFR FOR A PERIOD PRIOR TO
DAYBREAK. ALSO SOME FOG POSSIBLE AROUND KLYH-KDAN WHERE BRIEF MVFR
TO IFR POSSIBLE WHILE COVERAGE LOOKS QUITE SPOTTY AT KBLF WHERE
LIMITED TO JUST A VERY BRIEF INCLUSION OF MVFR CONDITIONS AROUND
DAWN.
FOR WEDNESDAY...SHOULD SEE ANY LOW CLOUDS/FOG FADE WITH THE ONSET
OF HEATING ALLOWING FOR VFR CONDITIONS TO QUICKLY RETURN BY MID
MORNING IF NOT SOONER. THEN EXPECT THE UPPER WAVE OVER THE OHIO
VALLEY TO SLOWLY SHIFT SOUTHEAST INTO VIRGINIA. THIS WILL ALLOW
MORE INSTABILITY WITH STEEPER LAPSE RATES AND LIFT. SHOWERS AND
STORMS WILL BE MORE SCATTERED WEDNESDAY AFTERNOON WITH BEST
FORCING ACROSS THE FOOTHILLS/PIEDMONT TO THE NEW RIVER VALLEY. AS
OF NOW WILL KEEP THE GOING VCTS AT KROA/KLYH AND KBCB AFTER
19Z/3PM...BUT THINK COVERAGE WILL BE LESS FURTHER WEST AND
SOUTHEAST...SO ONLY GOING WITH A VCSH AT KLWB-KBLF WHILE KEEPING
MENTION OUT OF KDAN.
OVERALL EXPECT VFR CONDITIONS WEDNESDAY WITH CIGS OF 4-6KFT WITH
TCU AND CB IN THE AFTERNOON.
EXTENDED AVIATION DISCUSSION...
THE FORECAST AREA WILL REMAIN IN A WEAKLY FORCED SYNOPTIC
ENVIRONMENT THROUGH THURSDAY...WITH CHANCES FOR DIURNAL
CONVECTION MAINLY FROM THE BLUE RIDGE WEST...AND SOME MVFR/IFR
FOG/STRATUS DEVELOPMENT AT NIGHT...ESPECIALLY AT KBCB AND KLWB.
FOR FRIDAY INTO SUNDAY WILL SEE HIGH PRESSURE IN CONTROL THOUGH
THE POSITION OF THE HIGH OVER THE MID ATLANTIC MAY SLIDE MORE MVFR
CIGS OFF THE ATLANTIC INTO OUR EASTERN TAF LOCATIONS.
&&
.EQUIPMENT...
AS OF 400 PM EDT TUESDAY...
THE DEW POINT READING AT KJFZ...RICHLANDS VA AWOS...IS INCORRECT.
AT THIS TIME WE DO NOT KNOW WHEN THIS SENSOR WILL BE REPAIRED.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/NF
NEAR TERM...JH
SHORT TERM...RAB
LONG TERM...AMS/RAB
AVIATION...JH/NF/WP
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
321 AM EDT WED SEP 2 2015
.SYNOPSIS...
A RIDGE OF HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH THE
END OF THE WEEK. UPPER LEVEL DISTURBANCES TRACKING THROUGH THE
RIDGING WILL RESULT IN WIDELY SCATTERED MAINLY DIURNAL SHOWERS
AND STORMS INTO FRIDAY. A WEAK BACKDOOR COLD FRONT WILL DROP
SOUTH THROUGH THE AREA BY THE END OF WEEK BRINGING SOMEWHAT DRIER
AND COOLER AIR FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 240 AM EDT WEDNESDAY...
OVERALL HOT AND HUMID WEATHER FOR EARLY SEPTEMBER TO PERSIST TODAY AS
SURFACE HIGH PRESSURE REMAINS IN PLACE ACROSS THE MOUNTAINS. HOWEVER
SHORTWAVE ENERGY IN THE FORM OF AN OPENING UPPER LOW ACROSS THE OHIO
VALLEY WILL RIDE SOUTHEAST THROUGH THE 5H RIDGE AND OVER THE NORTHERN
HALF OF THE AREA THIS AFTERNOON. THIS SHOULD RESULT IN BETTER LIFT
ESPCLY ALONG AND JUST SOUTH OF THE INTERSTATE 64 CORRIDOR EARLY ON AND
ACROSS THE EASTERN HALF THROUGH LATE IN THE DAY. LATEST GUIDANCE ALSO
SHOWING BETTER INSTABILITY WITH A LITTLE MORE COOLING ALOFT...BUT STILL
UNCERTAINTY WITH COVERAGE GIVEN OVERALL BROAD SUBSIDENCE IN PLACE UNDER
RATHER WARM 5H TEMPS. CURRENT SPC/RNK WRF SOLUTIONS ALONG WITH THE
LATEST HRRR REMAIN THE MOST WIDESPREAD WITH SHRA/TSRA NORTH HALF AND
ALONG THE BLUE RIDGE. THIS WHILE MOST OTHER SOLUTIONS INCLUDING
ENSEMBLES PRODUCING LESS INCLUDING ONLY WIDELY SCATTERED SHALLOW
CONVECTION MAINLY CONFINED FROM THE VIRGINIA HIGHLANDS EAST TO AROUND
KLYH FOR THE MOST PART. THEREFORE ALIGNED HIGHEST CHANCE POPS ACROSS
THE FAR NORTH WITH A PERIOD OF LOWER CHANCES SOUTH/EAST DURING MID/LATE
AFTERNOON AND ONLY ISOLATED COVERAGE FAR SW. GIVEN WEAK FLOW ALOFT NOT
EXPECTING MUCH OF A SEVERE THREAT BUT COULD SEE A BIT MORE CLUSTERING
OF SLOW MOVING CONVECTION RIGHT NEAR THE CORE OF THE UPPER WAVE LATE.
OTHERWISE LOOKING AT MAINLY PC WITH MID DECK EARLY...THEN MORE CU THIS
AFTERNOON WITH HIGHS AGAIN REACHING THE LOW 90S EAST AND WELL INTO THE
80S ELSEWHERE PENDING TIMING OF CONVECTIVE INITIATION.
IMPULSE PASSES THIS EVENING LEAVING THE REGION IN BETWEEN WAVES AND
UNDER SURFACE HIGH PRESSURE. THIS SHOULD ALLOW MOST CONVECTION TO FADE
BY MIDNIGHT GIVEN LOSS OF HEATING AND SOME OVERNIGHT CLEARING PER WEAK
NW FLOW ALOFT IN THE WAKE OF THE MID LEVEL SYSTEM. THUS KEEPING SOME
LOW END CHANCE POPS GOING MAINLY EAST THIS EVENING BEFORE TRENDING DRY
WITH FOG AGAIN OVERNIGHT. LOWS PERHAPS SLIGHTLY COOLER GIVEN SOME DROP
IN DEWPOINTS AND ESPCLY WHERE ANY COOLING EVENING RAINFALL OCCURS BUT
STILL MOSTLY LOW/MID 60S MOUNTAINS TO UPPER 60S EAST.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
AS OF 345 PM EDT TUESDAY...
THE GFS MOVES THE OHIO SHORT WAVE SLOWER THAN THE NAM/SREF. GIVEN
THE LACK OF A KICKER FOR THIS VORT MAX...THE SLOWER GFS SEEMS MORE
REASONABLE...BUT EVEN ON THIS SLOWER TRACK THE SHORT WAVE WILL STILL
BE SOUTHEAST OF THE FORECAST AREA BY THURSDAY AFTERNOON. WILL EXTEND
THE PROBABILITY OF PRECIPITATION IN THE FORECAST FOR WEDNESDAY
NIGHT. STAYED CLOSER TO MAV GUIDANCE THROUGH THE PERIOD.
BACKDOOR FRONT MOVES SOUTH THROUGH THE NEW ENGLAND AND MID ATLANTIC
COAST. MODELS WERE SHOWING SOME CONVERGENCE IN EASTERN VIRGINIA BUT
STILL QUESTIONABLE HOW MUCH LIFT THIS FEATURE MAY PROVIDE FOR THE
COUNTY WARNING AREA. BEST PROBABILITY OF PRECIPITATION WILL BE IN
THE NORTHEAST COUNTIES OF THE FORECAST AREA...EAST OF THE BLUE
RIDGE. AS THIS FRONT MOVES DOWN THE COAST AND HIGH PRESSURE BUILDS
SOUTH OVER THE APPALACHIANS...WINDS WILL TURN FROM NORTH TO EAST.
THIS EASTERLY COMPONENT OF THE WIND AT THE SURFACE THROUGH LOW
LEVELS MAY ALSO EXPAND THE CLOUD COVER AND PROBABILITY OF
PRECIPITATION ALONG THE BLUE RIDGE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 100 PM EDT TUESDAY...
LOWER 500 MB HEIGHTS REMAINED TRAPPED UNDER THE RIDGE OVER THE
SOUTHEAST UNITED STATES FRIDAY NIGHT THROUGH SUNDAY. SUNDAY NIGHT
INTO TUESDAY...THE CENTER OF THE UPPER RIDGE...DRIFTS SOUTH INTO THE
MID ATLANTIC REGION. HEIGHTS WILL BE CLOSE TO 594DM ACCORDING TO THE
00Z GFS. AT THE SURFACE FRIDAY NIGHT ANY REMNANTS OF THE BACKDOOR
FRONT WASH OUT AND BY SATURDAY THE WEDGE WILL BE FULLY ESTABLISHED
AND THIS FEATURE WILL REMAIN IN PLACE THROUGH SUNDAY. HIGH PRESSURE
WILL COVER THE MID ATLANTIC STATES THROUGH TUESDAY. UNSEASONABLY
WARM TEMPERATURES...WITH 850 MB TEMPERATURES APPROACHING +20...MOVE
INTO THE REGION WITH THE HIGHER HEIGHTS.
A DRIER AIR MASS BEGINS TO APPROACH THE REGION AS THE WEDGE BUILDS
IN ON SATURDAY. SUNDAY AND MONDAY...ECMWF WAS SHOWING MUCH DRIER AIR
ABOVE 850MB. BELOW 850 MB THE DRIER AIR REMAINS EAST AND SOUTH OF
THE FORECAST AREA THROUGH MONDAY.
&&
.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
AS OF 100 AM EDT WEDNESDAY...
OTHER THAN FOR DEBRIS MID/HIGH CLOUDS...FOG THE MAIN CONCERN
OVERNIGHT WITH POTENTIAL AGAIN GIVEN LESS CLOUDS OF SEEING THE
VALLEYS SUCH AS KLWB/KBCB DROP INTO LIFR/IFR FOR A PERIOD PRIOR TO
DAYBREAK. ALSO SOME FOG POSSIBLE AROUND KLYH-KDAN WHERE BRIEF MVFR
TO IFR POSSIBLE WHILE COVERAGE LOOKS QUITE SPOTTY AT KBLF WHERE
LIMITED TO JUST A VERY BRIEF INCLUSION OF MVFR CONDITIONS AROUND
DAWN.
FOR WEDNESDAY...SHOULD SEE ANY LOW CLOUDS/FOG FADE WITH THE ONSET
OF HEATING ALLOWING FOR VFR CONDITIONS TO QUICKLY RETURN BY MID
MORNING IF NOT SOONER. THEN EXPECT THE UPPER WAVE OVER THE OHIO
VALLEY TO SLOWLY SHIFT SOUTHEAST INTO VIRGINIA. THIS WILL ALLOW
MORE INSTABILITY WITH STEEPER LAPSE RATES AND LIFT. SHOWERS AND
STORMS WILL BE MORE SCATTERED WEDNESDAY AFTERNOON WITH BEST
FORCING ACROSS THE FOOTHILLS/PIEDMONT TO THE NEW RIVER VALLEY. AS
OF NOW WILL KEEP THE GOING VCTS AT KROA/KLYH AND KBCB AFTER
19Z/3PM...BUT THINK COVERAGE WILL BE LESS FURTHER WEST AND
SOUTHEAST...SO ONLY GOING WITH A VCSH AT KLWB-KBLF WHILE KEEPING
MENTION OUT OF KDAN.
OVERALL EXPECT VFR CONDITIONS WEDNESDAY WITH CIGS OF 4-6KFT WITH
TCU AND CB IN THE AFTERNOON.
EXTENDED AVIATION DISCUSSION...
THE FORECAST AREA WILL REMAIN IN A WEAKLY FORCED SYNOPTIC
ENVIRONMENT THROUGH THURSDAY...WITH CHANCES FOR DIURNAL
CONVECTION MAINLY FROM THE BLUE RIDGE WEST...AND SOME MVFR/IFR
FOG/STRATUS DEVELOPMENT AT NIGHT...ESPECIALLY AT KBCB AND KLWB.
FOR FRIDAY INTO SUNDAY WILL SEE HIGH PRESSURE IN CONTROL THOUGH
THE POSITION OF THE HIGH OVER THE MID ATLANTIC MAY SLIDE MORE MVFR
CIGS OFF THE ATLANTIC INTO OUR EASTERN TAF LOCATIONS.
&&
.EQUIPMENT...
AS OF 400 PM EDT TUESDAY...
THE DEW POINT READING AT KJFZ...RICHLANDS VA AWOS...IS INCORRECT.
AT THIS TIME WE DO NOT KNOW WHEN THIS SENSOR WILL BE REPAIRED.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/NF
NEAR TERM...JH
SHORT TERM...AMS
LONG TERM...AMS
AVIATION...JH/NF/WP
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1135 AM CDT WED SEP 2 2015
.UPDATE...THIS AFTERNOON
ISSUED AT 1134 AM CDT WED SEP 2 2015
WITH THE NORTHERN SHORT WAVE BECOMING THE MORE DOMINANT ONE THIS
MORNING AND A STRONG 750 TO 400 MB CAP COMING IN THE WAKE OF THE
SHORT WAVE...THE CHANCE OF SHOWERS AND THUNDERSTORMS SOUTH OF
INTERSTATE 94 WERE REMOVED FOR THIS AFTERNOON AND EVENING.
THIS WILL RESULT IN MORE SUNSHINE THAN ORIGINALLY ANTICIPATED...SO
RAISED THE HIGH TEMPERATURES ANYWHERE FROM 3 TO 5 DEGREES WHICH
INCREASED THE HEAT INDICES INTO THE LOWER TO MID 90S.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 300 AM CDT WED SEP 2 2015
DATA ANALYSIS THIS MORNING FEATURES A MID-LEVEL TROUGH/MCV MAKING
ITS WAY ACROSS SOUTH-CENTRAL MN/CENTRAL IA TOWARD THE UPPER
MISSISSIPPI RIVER VALLEY REGION. THERE HAS BEEN SOME EFFICIENT RAIN-
MAKERS EMBEDDED WITHIN THIS COMPLEX OF CONVECTION GIVEN HUMID/HIGHER
PRECIPITABLE WATER ENVIRONMENT. FEW HOURLY PRECIPITATION REPORTS
COMING IN FROM 3/4 TO JUST OVER AN INCH. OTHERWISE...MUGGY EARLY
MORNING ACROSS THE AREA WITH TEMPERATURES/DEW POINTS IN THE UPPER
60S TO THE MIDDLE 70S.
WILL BE WATCHING THE TROUGH/MCV CONTINUE MOVING ACROSS OUR AREA
TODAY. RAP SHOWING DECENT PUSH OF 850-700MB MOISTURE TRANSPORT
CONTINUING THROUGH 18Z. SO...EXPECTING THIS CONVECTIVE COMPLEX TO
HOLD TOGETHER THROUGH THIS MORNING WITH CHANCES FALLING OFF DURING
THE AFTERNOON FROM WEST TO EAST AS BETTER MOISTURE PUSHES EAST WITH
THE TROUGH. HIGHEST CONCENTRATION OF SHOWERS/STORMS LOOK TO BE NORTH
OF I-90 OR NOSE OF THE BETTER 850-700MB MOISTURE TRANSPORT. ALTHOUGH
SEVERE WEATHER IS NOT ANTICIPATED TO BE WIDESPREAD TODAY GIVEN LOW-
END BULK SHEAR FOR ORGANIZATION...COULD BE SOME SPORADIC HIGHER WIND
GUSTS MIXED IN WITH HEAVIER DOWNPOURS. PLAN ON MUGGY CONDITIONS
OTHERWISE WITH HIGHS IN THE 80S AND DEW POINTS STAYING IN THE UPPER
60S TO LOWER 70S. THIS WILL PUT HEAT INDICES IN THE 90-95 DEGREE
RANGE MAINLY SOUTH OF I-90.
LINGERING SHOWER/THUNDERSTORM CHANCES CONTINUE THROUGH TONIGHT AS
WANING 850-700MB MOISTURE TRANSPORT IMPINGES ON SURFACE TROUGH/WARM
FRONTAL BOUNDARY EAST OF THE MISSISSIPPI RIVER. LOOK FOR MUGGY
OVERNIGHT TEMPERATURES IN THE MIDDLE 60S TO NEAR 70.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 300 AM CDT WED SEP 2 2015
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL POSSIBLE ACROSS
CENTRAL WISCONSIN THURSDAY AS THIS AREA WILL BE ALONG THAT
AFOREMENTIONED SURFACE TROUGH/WARM FRONTAL BOUNDARY AND VERY WEAK
850MB MOISTURE TRANSPORT. OTHERWISE...ANOTHER MUGGY DAY ON TAP WITH
HIGHS IN THE 80S AND DEW POINTS HANGING IN THE UPPER 60S/LOWER 70S.
HEAT INDICES ARE EXPECTED TO TOP OFF IN THE 90-95 DEGREE RANGE.
FRIDAY APPEARS DRY BUT RAIN CHANCES INTO THE WEEKEND WILL HANG ON
DISTURBANCES EJECTING OUT OF MONSOONAL FLOW OVER THE SOUTHWEST.
MODELS SEEM TO BE HAVING A DIFFICULT TIME HANDLING THESE FEATURES IN
DETAIL...YIELDING LOW-END SHOWER/THUNDERSTORM CHANCES SATURDAY.
APPEARS LATEST ECMWF/GFS ARE CONVERGING ON SLIGHTLY FASTER TIMING ON
INCOMING MID-LEVEL TROUGH/SURFACE COLD FRONT FROM THE NORTHERN
PLAINS SUNDAY INTO MONDAY. APPEARS HIGHEST SHOWER/THUNDERSTORM
CHANCES WILL BE SUNDAY NIGHT WITH THE COLD FRONT POSSIBLY CLEARING
THE AREA BY AFTERNOON ON LABOR DAY. OTHERWISE...STILL LOOKING HOT
AND MUGGY SATURDAY AND SUNDAY WITH HIGHS WELL INTO THE 80S AND HEAT
INDICES IN THE UPPER 80S TO MIDDLE 90S.
TUESDAY WILL SEE A CHANCE OF SHOWERS AND STORMS ACROSS NORTHEAST IA
INTO FAR SOUTHWEST WI AS THE COLD FRONT STALLS OUT JUST SOUTH OF
THAT AREA. COOLER/DRIER AIR IS ON TAP OTHERWISE WITH HIGHS LOOKING
TO BE IN THE UPPER 60S ACROSS NORTHERN WI...TO THE LOWER/MIDDLE 70S
SOUTH OF I-90.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1134 AM CDT WED SEP 2 2015
SKIES WILL BE MOSTLY SUNNY THIS AFTERNOON AT THE TAF SITES THIS
AFTERNOON. DIURNAL HEATING WILL ALLOW THE SOUTH WINDS TO GUST INTO
THE 20 TO 25 KNOT RANGE. THESE WIND GUSTS WILL CONTINUE THROUGH
03/02Z.
THE SOUNDINGS OVERNIGHT DO NOT LOOK FAVORABLE FOR DENSE FOG AT
EITHER TAF SITES TONIGHT. HOWEVER THERE WILL STILL BE A
POSSIBILITY THAT FOG MAY STILL REDUCE VISIBILITIES TO 3 TO 5
STATUE MILES LATE BETWEEN 03.09Z AND 03.13Z. WHILE DENSE FOG DOES
NOT LOOK FAVORABLE FOR THE TAF SITES...IT DOES LOOK FAVORABLE FOR
CENTRAL AND NORTH CENTRAL WISCONSIN.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...BOYNE
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
630 AM CDT WED SEP 2 2015
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 300 AM CDT WED SEP 2 2015
DATA ANALYSIS THIS MORNING FEATURES A MID-LEVEL TROUGH/MCV MAKING
ITS WAY ACROSS SOUTH-CENTRAL MN/CENTRAL IA TOWARD THE UPPER
MISSISSIPPI RIVER VALLEY REGION. THERE HAS BEEN SOME EFFICIENT RAIN-
MAKERS EMBEDDED WITHIN THIS COMPLEX OF CONVECTION GIVEN HUMID/HIGHER
PRECIPITABLE WATER ENVIRONMENT. FEW HOURLY PRECIPITATION REPORTS
COMING IN FROM 3/4 TO JUST OVER AN INCH. OTHERWISE...MUGGY EARLY
MORNING ACROSS THE AREA WITH TEMPERATURES/DEW POINTS IN THE UPPER
60S TO THE MIDDLE 70S.
WILL BE WATCHING THE TROUGH/MCV CONTINUE MOVING ACROSS OUR AREA
TODAY. RAP SHOWING DECENT PUSH OF 850-700MB MOISTURE TRANSPORT
CONTINUING THROUGH 18Z. SO...EXPECTING THIS CONVECTIVE COMPLEX TO
HOLD TOGETHER THROUGH THIS MORNING WITH CHANCES FALLING OFF DURING
THE AFTERNOON FROM WEST TO EAST AS BETTER MOISTURE PUSHES EAST WITH
THE TROUGH. HIGHEST CONCENTRATION OF SHOWERS/STORMS LOOK TO BE NORTH
OF I-90 OR NOSE OF THE BETTER 850-700MB MOISTURE TRANSPORT. ALTHOUGH
SEVERE WEATHER IS NOT ANTICIPATED TO BE WIDESPREAD TODAY GIVEN LOW-
END BULK SHEAR FOR ORGANIZATION...COULD BE SOME SPORADIC HIGHER WIND
GUSTS MIXED IN WITH HEAVIER DOWNPOURS. PLAN ON MUGGY CONDITIONS
OTHERWISE WITH HIGHS IN THE 80S AND DEW POINTS STAYING IN THE UPPER
60S TO LOWER 70S. THIS WILL PUT HEAT INDICES IN THE 90-95 DEGREE
RANGE MAINLY SOUTH OF I-90.
LINGERING SHOWER/THUNDERSTORM CHANCES CONTINUE THROUGH TONIGHT AS
WANING 850-700MB MOISTURE TRANSPORT IMPINGES ON SURFACE TROUGH/WARM
FRONTAL BOUNDARY EAST OF THE MISSISSIPPI RIVER. LOOK FOR MUGGY
OVERNIGHT TEMPERATURES IN THE MIDDLE 60S TO NEAR 70.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 300 AM CDT WED SEP 2 2015
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL POSSIBLE ACROSS
CENTRAL WISCONSIN THURSDAY AS THIS AREA WILL BE ALONG THAT
AFOREMENTIONED SURFACE TROUGH/WARM FRONTAL BOUNDARY AND VERY WEAK
850MB MOISTURE TRANSPORT. OTHERWISE...ANOTHER MUGGY DAY ON TAP WITH
HIGHS IN THE 80S AND DEW POINTS HANGING IN THE UPPER 60S/LOWER 70S.
HEAT INDICES ARE EXPECTED TO TOP OFF IN THE 90-95 DEGREE RANGE.
FRIDAY APPEARS DRY BUT RAIN CHANCES INTO THE WEEKEND WILL HANG ON
DISTURBANCES EJECTING OUT OF MONSOONAL FLOW OVER THE SOUTHWEST.
MODELS SEEM TO BE HAVING A DIFFICULT TIME HANDLING THESE FEATURES IN
DETAIL...YIELDING LOW-END SHOWER/THUNDERSTORM CHANCES SATURDAY.
APPEARS LATEST ECMWF/GFS ARE CONVERGING ON SLIGHTLY FASTER TIMING ON
INCOMING MID-LEVEL TROUGH/SURFACE COLD FRONT FROM THE NORTHERN
PLAINS SUNDAY INTO MONDAY. APPEARS HIGHEST SHOWER/THUNDERSTORM
CHANCES WILL BE SUNDAY NIGHT WITH THE COLD FRONT POSSIBLY CLEARING
THE AREA BY AFTERNOON ON LABOR DAY. OTHERWISE...STILL LOOKING HOT
AND MUGGY SATURDAY AND SUNDAY WITH HIGHS WELL INTO THE 80S AND HEAT
INDICES IN THE UPPER 80S TO MIDDLE 90S.
TUESDAY WILL SEE A CHANCE OF SHOWERS AND STORMS ACROSS NORTHEAST IA
INTO FAR SOUTHWEST WI AS THE COLD FRONT STALLS OUT JUST SOUTH OF
THAT AREA. COOLER/DRIER AIR IS ON TAP OTHERWISE WITH HIGHS LOOKING
TO BE IN THE UPPER 60S ACROSS NORTHERN WI...TO THE LOWER/MIDDLE 70S
SOUTH OF I-90.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 630 AM CDT WED SEP 2 2015
02.1130Z REGIONAL RADAR SHOWS A LINE OF SHOWERS WITH EMBEDDED
THUNDERSTORMS FROM NORTH-CENTRAL WI TO SOUTHEAST MN AND INTO
EASTERN IA...MOVING EAST-NORTHEAST AROUND 25 KTS. EXPECT THIS
LINE OF STORMS TO IMPACT BOTH KRST/KLSE...ALTHOUGH IT SHOULD
WEAKEN AS IT MOVES EAST. COULD SEE BRIEF MVFR CEILINGS/VISIBILITY
AT KRST AS STRONGEST STORMS MOVE THROUGH BETWEEN 02.12Z AND
02.14Z...BUT WILL KEEP VFR CONDITIONS AT KLSE WITH STORM TIMING
FROM 02.13Z TO 02.15Z. ONCE STORMS MOVE EAST OF TAF AIRFIELDS...
EXPECT A RETURN TO VFR CONDITIONS WITH ONLY SOME AFTERNOON CUMULUS
BEFORE CLEARING OUT THIS EVENING AND OVERNIGHT. DESPITE MOSTLY
CLEAR SKIES TONIGHT...THINK WESTERLY WINDS FROM 20 TO 30 KTS AT
THE TOP OF NOCTURNAL BOUNDARY LAYER WILL PRECLUDE FOG FORMATION.
COULD SEE SOME MVFR VISIBILITY IN MIST...BUT NOT ENOUGH
CONFIDENCE TO INCLUDE AT THIS TIME.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...ROGERS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
300 AM CDT WED SEP 2 2015
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 300 AM CDT WED SEP 2 2015
DATA ANALYSIS THIS MORNING FEATURES A MID-LEVEL TROUGH/MCV MAKING
ITS WAY ACROSS SOUTH-CENTRAL MN/CENTRAL IA TOWARD THE UPPER
MISSISSIPPI RIVER VALLEY REGION. THERE HAS BEEN SOME EFFICIENT RAIN-
MAKERS EMBEDDED WITHIN THIS COMPLEX OF CONVECTION GIVEN HUMID/HIGHER
PRECIPITABLE WATER ENVIRONMENT. FEW HOURLY PRECIPITATION REPORTS
COMING IN FROM 3/4 TO JUST OVER AN INCH. OTHERWISE...MUGGY EARLY
MORNING ACROSS THE AREA WITH TEMPERATURES/DEW POINTS IN THE UPPER
60S TO THE MIDDLE 70S.
WILL BE WATCHING THE TROUGH/MCV CONTINUE MOVING ACROSS OUR AREA
TODAY. RAP SHOWING DECENT PUSH OF 850-700MB MOISTURE TRANSPORT
CONTINUING THROUGH 18Z. SO...EXPECTING THIS CONVECTIVE COMPLEX TO
HOLD TOGETHER THROUGH THIS MORNING WITH CHANCES FALLING OFF DURING
THE AFTERNOON FROM WEST TO EAST AS BETTER MOISTURE PUSHES EAST WITH
THE TROUGH. HIGHEST CONCENTRATION OF SHOWERS/STORMS LOOK TO BE NORTH
OF I-90 OR NOSE OF THE BETTER 850-700MB MOISTURE TRANSPORT. ALTHOUGH
SEVERE WEATHER IS NOT ANTICIPATED TO BE WIDESPREAD TODAY GIVEN LOW-
END BULK SHEAR FOR ORGANIZATION...COULD BE SOME SPORADIC HIGHER WIND
GUSTS MIXED IN WITH HEAVIER DOWNPOURS. PLAN ON MUGGY CONDITIONS
OTHERWISE WITH HIGHS IN THE 80S AND DEW POINTS STAYING IN THE UPPER
60S TO LOWER 70S. THIS WILL PUT HEAT INDICES IN THE 90-95 DEGREE
RANGE MAINLY SOUTH OF I-90.
LINGERING SHOWER/THUNDERSTORM CHANCES CONTINUE THROUGH TONIGHT AS
WANING 850-700MB MOISTURE TRANSPORT IMPINGES ON SURFACE TROUGH/WARM
FRONTAL BOUNDARY EAST OF THE MISSISSIPPI RIVER. LOOK FOR MUGGY
OVERNIGHT TEMPERATURES IN THE MIDDLE 60S TO NEAR 70.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 300 AM CDT WED SEP 2 2015
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS STILL POSSIBLE ACROSS
CENTRAL WISCONSIN THURSDAY AS THIS AREA WILL BE ALONG THAT
AFOREMENTIONED SURFACE TROUGH/WARM FRONTAL BOUNDARY AND VERY WEAK
850MB MOISTURE TRANSPORT. OTHERWISE...ANOTHER MUGGY DAY ON TAP WITH
HIGHS IN THE 80S AND DEW POINTS HANGING IN THE UPPER 60S/LOWER 70S.
HEAT INDICES ARE EXPECTED TO TOP OFF IN THE 90-95 DEGREE RANGE.
FRIDAY APPEARS DRY BUT RAIN CHANCES INTO THE WEEKEND WILL HANG ON
DISTURBANCES EJECTING OUT OF MONSOONAL FLOW OVER THE SOUTHWEST.
MODELS SEEM TO BE HAVING A DIFFICULT TIME HANDLING THESE FEATURES IN
DETAIL...YIELDING LOW-END SHOWER/THUNDERSTORM CHANCES SATURDAY.
APPEARS LATEST ECMWF/GFS ARE CONVERGING ON SLIGHTLY FASTER TIMING ON
INCOMING MID-LEVEL TROUGH/SURFACE COLD FRONT FROM THE NORTHERN
PLAINS SUNDAY INTO MONDAY. APPEARS HIGHEST SHOWER/THUNDERSTORM
CHANCES WILL BE SUNDAY NIGHT WITH THE COLD FRONT POSSIBLY CLEARING
THE AREA BY AFTERNOON ON LABOR DAY. OTHERWISE...STILL LOOKING HOT
AND MUGGY SATURDAY AND SUNDAY WITH HIGHS WELL INTO THE 80S AND HEAT
INDICES IN THE UPPER 80S TO MIDDLE 90S.
TUESDAY WILL SEE A CHANCE OF SHOWERS AND STORMS ACROSS NORTHEAST IA
INTO FAR SOUTHWEST WI AS THE COLD FRONT STALLS OUT JUST SOUTH OF
THAT AREA. COOLER/DRIER AIR IS ON TAP OTHERWISE WITH HIGHS LOOKING
TO BE IN THE UPPER 60S ACROSS NORTHERN WI...TO THE LOWER/MIDDLE 70S
SOUTH OF I-90.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1055 PM CDT TUE SEP 1 2015
A WEAK WEATHER SYSTEM WILL BE MOVING ACROSS THE AIRFIELDS LATER
TONIGHT AND WEDNESDAY. THERE IS SOME INSTABILITY
PRESENT...CONDITIONAL UPON THE AIR BEING ABLE TO SATURATE. CURRENT
OBSERVATIONS SHOW A -TSRA COMPLEX OVER SWRN MN SHIFTING
NORTHEAST. THERE IS A CHANCE THIS COULD EXPAND SOUTH AND AFFECT
THE TAFS DURING THE MORNING HOURS. HOWEVER...THE AIR APPEARS TO BE
STABLE ENOUGH TO ONLY CAUSE ISOLATED HIGHER BASED ACCAS.
THUS...CONTINUED FORECAST TREND OF NOT INCLUDING TSRA AT THE
AIRFIELDS FOR THE 06Z TAFS.
SOME MVFR FOG MAY BE AROUND LATER TONIGHT AS THE VERY NEAR-SURFACE
AIR MASS IS MORE MOIST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION
NWS TUCSON AZ
955 PM MST THU SEP 3 2015
.SYNOPSIS...SCATTERED MAINLY AFTERNOON AND EVENING THUNDERSTORMS
WILL OCCUR ESPECIALLY FROM TUCSON EAST AND SOUTH INTO EARLY
NEXT WEEK. EXPECT REDUCED THUNDERSTORM CHANCES BY NEXT WEDNESDAY.
BELOW NORMAL DAYTIME TEMPERATURES WILL PREVAIL THROUGH THIS
WEEKEND...THEN HIGH TEMPERATURES RETURNING CLOSE TO SEASONAL NORMALS
BY THE MIDDLE OF NEXT WEEK.
&&
.DISCUSSION...DRY CONDITIONS WERE ONGOING ACROSS SE ARIZONA WITH THE
EXCEPTION OF ISOLATED SHOWERS PRODUCING LIGHT RAINFALL ACROSS
CENTRAL/SRN GRAHAM COUNTY. OTHERWISE...IR SATELLITE IMAGERY AND
SURFACE OBSERVATIONS INDICATED MOSTLY CLEAR SKIES ACROSS WRN PIMA
COUNTY...AND PARTLY CLOUDY TO CLOUDY SKIES PREVAILED ELSEWHERE.
PATCHY FOG HAD DEVELOPED DURING ABOUT THE PAST HOUR AS PER THE KOLS
METARS.
BASED ON SATELLITE/RADAR TRENDS AS WELL AS THE 04/00Z NAM12 AND
SEVERAL HRRR SOLUTIONS...HAVE MAINTAINED A SLIGHT CHANCE OF SHOWERS
ACROSS MUCH OF SE ARIZONA THE REST OF TONIGHT. PRECIP-FREE
CONDITIONS WILL CONTINUE ACROSS WRN PIMA COUNTY. HAVE ALSO INCLUDED
PATCHY FOG THRU 15Z FRIDAY FOR ERN PIMA COUNTY AND SANTA CRUZ COUNTY.
QUICK GLANCE AT THE 04/00Z UNIV OF AZ WRF-NAM SUGGESTS MARKEDLY
REDUCED COVERAGE OF SHOWERS/TSTMS VERSUS TODAY. FOR NOW...HAVE
MAINTAINED SCATTERED SHOWERS/TSTMS ACROSS MUCH OF THE AREA FRI
AFTERNOON/EVENING. HIGH TEMPS FRI ARE FORECAST TO BE ABOUT 5-10 DEGS
BELOW NORMAL.
PLEASE REFER TO THE ADDITIONAL SECTIONS FOR FURTHER DETAIL.
&&
.AVIATION...VALID THRU 05/06Z.
ISOLATED -SHRA INTO EARLY FRIDAY MORNING FOLLOWED BY SCATTERED
-TSRA/-SHRA FROM LATE FRIDAY MORNING INTO FRIDAY EVENING. MVFR
CONDITIONS AND LOCAL IFR CONDITIONS WILL OCCUR WITH THE STRONGER
TSRA. EXPECT VISIBILITIES REDUCED AS LOW AS 1/2SM IN FOG IN THE
VICINITY OF THE KOLS TERMINAL THRU AROUND 15Z FRIDAY. THERE IS ALSO
A SLIGHT CHANCE OF REDUCED VISIBILITIES PERHAPS TO AROUND 3SM AT
KTUS THRU 15Z FRIDAY. HOWEVER...FORECAST CONFIDENCE OF THIS
OCCURRENCE IS TOO LOW TO INCLUDE IN THE TAFS. OTHERWISE...CLOUD
DECKS WILL GENERALLY RANGE FROM 10-15K FT AGL AND SURFACE WIND WILL
GENERALLY BE LESS THAN 10 KTS. AVIATION DISCUSSION NOT UPDATED FOR
TAF AMENDMENTS.
&&
.FIRE WEATHER...EXPECT SCATTERED MAINLY AFTERNOON AND EVENING
THUNDERSTORMS INTO EARLY NEXT WEEK. LOCALLY HEAVY RAINFALL AND
BRIEF GUSTY WINDS WILL ACCOMPANY THE STRONGER THUNDERSTORMS. TYPICAL
THUNDERSTORM GUSTS WILL BE 25-35 MPH WITH STRONGER STORMS GUSTING TO
OVER 50 MPH. OUTSIDE OF THUNDERSTORM GUSTS...20-FT WINDS WILL BE
TERRAIN DRIVEN AND MAINLY LESS THAN 15 MPH INTO NEXT WEEK. ISOLATED
TO SCATTERED MAINLY AFTERNOON AND EVENING THUNDERSTORMS WILL THEN
PREVAIL BY THE MIDDLE OF THE UPCOMING WEEK.
&&
.PREV DISCUSSION /245 PM MST/...DEEP MOISTURE PLUME IS EXPECTED TO
CONTINUE TO STREAM NORTHEAST INTO SOUTHERN ARIZONA OFF OF TROPICAL
STORM KEVIN ON FRIDAY WITH ADDITIONAL WEAK EMBEDDED IMPULSES
FORECASTED TO MOVE THROUGH THE AREA. THIS WILL CONTINUE THE HIGH END
SCATTERED POP CHANCES FOR FRIDAY AFTERNOON/EVENING. GIVEN THE
EXPECTED CLOUD COVER...MOISTURE...AND PRECIPITATION CHANCES
FRIDAY...AFTERNOON HIGH TEMPERATURES WILL BE NEARLY 10 DEGREES BELOW
SEASONAL AVERAGES...WITH HIGHS IN THE TUCSON METRO AREA EXPECTED TO
TOP OUT IN THE UPPER 80S.
AFTER FRIDAY...THE MODEL SOUNDINGS INDICATE LOWERING ATMOSPHERIC
MOISTURE THROUGH EARLY NEXT WEEK...WITH CORRESPONDING PRECIPITATION
CHANCES FALLING BACK INTO THE ISOLATED TO SCATTERED RANGE. READINGS
WILL WARM A COUPLE OF DEGREES EACH DAY IN THE SATURDAY THROUGH
MONDAY TIME FRAME...WITH DAYTIME HIGH TEMPERATURES NEAR NORMAL BY
EARLY NEXT WEEK. BY MID TO LATE NEXT WEEK...THE MODELS MOVE THE
UPPER HIGH OFF THE CALIFORNIA COAST...WITH A DRYING WESTERLY FLOW
ACROSS THE FORECAST AREA.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1206 AM CDT FRI SEP 4 2015
.UPDATE...
ISSUED AT 656 PM CDT THU SEP 3 2015
ISOLATED SHOWER/STORM WORDING HAS BEEN ADDED N CENTRAL TO E
CENTRAL IA. ELEVATED CONVECTION HAS DEVELOPED ON LEADING EDGE OF
WEAK WARM ADVECTION...LIKELY ROOTED FAIRLY HIGH ABOVE 2KM BASED ON
FORECAST SOUNDINGS. HAVE ONLY ADDED A FEW HOURS AT THIS
POINT...BUT MAY HAVE TO EXTEND AS IT MAY MAINTAIN ITSELF INTO THE
NIGHT WITH TYPICAL NOCTURNAL WARM ADVECTION CYCLE.
&&
.SHORT TERM /TONIGHT/...
ISSUED AT 332 PM CDT THU SEP 3 2015
MAIN FORECAST CONCERN WAS FOCUSED ON TEMPERATURES AND FOG
POTENTIAL OVER NORTHERN IOWA. OVERNIGHT LOWS LOOK TO FINALLY REACH
THE CROSSOVER TEMP BY B/T 07-09Z OVER THE NORTH AND LIKELY SEE FOG
DEVELOP DURING THAT TIME FRAME. NAM/SREF SUGGEST FOG DEVELOPING FROM
MOW TO EST AND POSSIBLY AS FAR SOUTH AS HIGHWAY 20. THE CAVEAT IS
A WEAK SHORTWAVE OVER NEBRASKA/SOUTH DAKOTA MAY BRING IN SOME
HIGHER CLOUDS TOWARDS FRIDAY MORNING...SO ONLY MENTIONED PATCHY
FOG ATOM. THE LATEST HRRR (03.18Z) AND EVEN THE GFS HAVE A HINT
OF CONVECTION DEVELOPING OVER THE NORTHWEST TOWARDS FRIDAY MORNING
IN RESPONSE TO THE LAW DEVELOPING AND ASSOCIATED WITH
AFOREMENTIONED WEAK SHORTWAVE. THINKING THE NAM/ECMWF HAS A BETTER
HANDLE ON TIMING AND LOCATION AND LEFT FORECAST DRY.
.LONG TERM /FRIDAY THROUGH THURSDAY/...
ISSUED AT 332 PM CDT THU SEP 3 2015
PATTERN REMAINS SIMILAR THROUGH THE BEGINNING OF THE MID/LONG RANGE
WITH UPPER RIDGING IN PLACE ALOFT WITH A TROUGH DIGGING INTO THE
WESTERN US. A FEW WEAK IMPULSES WILL MOVE JUST TO THE WEST OF THE
CWA WHICH COULD LEAD TO SOME INCREASED CLOUDINESS...BUT OVERALL
CHANCE OF PRECIPITATION IS SMALL SO HAVE A DRY FORECAST INTO
SATURDAY. UPPER LEVEL RIDGE TO FLATTEN SOME OVER THE WEEKEND AS THE
WESTERN US TROUGH LIFTS NORTHEASTWARD INTO SOUTHERN CANADIAN PRAIRIE
PROVINCES BY LATE SUNDAY. SOUTHERLY FLOW WILL INCREASE AHEAD OF THIS
SYSTEM SATURDAY NIGHT INTO SUNDAY...WITH MOISTURE ADVECTION AND
MOISTURE TRANSPORT BECOMING ORIENTED INTO WESTERN IOWA. MAY SEE SOME
STORMS BUBBLE UP ACROSS THE WESTERN/NORTHWESTERN CWA...BUT OVERALL
WIDESPREAD PRECIPITATION CHANCES NOT EXPECTED UNTIL THE PASSAGE OF
THE COLD FRONT ASSOCIATED WITH THE CANADIAN SYSTEM SUNDAY NIGHT.
THIS FRONT WILL ELIMINATE THE CURRENT HOT AND MUGGY CONDITIONS...AS
H85 TEMPS DROP INTO THE TEENS BEHIND THE FRONT. LONG RANGE IN MODELS
IN SOME DISAGREEMENT INTO NEXT WEEK WITH HOW FAST TO PUSH THE FRONT
SOUTH...WITH THE EC HANGING THE FRONT UP ACROSS SOUTHERN IOWA WITH
CHANCES FOR STORMS CONTINUING INTO MONDAY/MONDAY NIGHT. GFS TRIES TO
PUSH IT INTO MISSOURI...WHICH WOULD KEEP IOWA DRIER MONDAY. FULL
WESTERN US TROUGH TO SHOVE EAST TUESDAY WITH THE FRONT LIFTING
BACK NORTHWARD AS A WARM FRONT LATE MONDAY NIGHT/EARLY TUESDAY
BEFORE A STRONGER COLD FRONT PUSHES THROUGH LATE TUESDAY INTO
TUESDAY NIGHT. H85 TEMPS TO DROP ANOTHER CATEGORY INTO THE LOW
TEENS BEHIND THIS FRONT WITH HIGH PRESSURE EXPECTED TO BUILD IN
FOR THE REST OF THE WEEK. THIS SHOULD LEAD TO MAINLY DRY
CONDITIONS FOR MUCH OF WEDNESDAY INTO THE END OF THE WEEK. MODELS
DO HINT AT A WEAK TROUGH CLIPPING NORTHERN IOWA THURSDAY WHICH
COULD BRING SOME SPRINKLES TO MAINLY NORTHEASTERN IOWA. HAVE A
SMALL AREA OF SLIGHT CHANCE POP FOR THIS FEATURE. OTHERWISE
RELEGATED POPS MAINLY TO THE TIME PERIODS WITH THE FRONTAL
PASSAGES WITH TEMPS EXPECTED TO FALL MORE TOWARD OR SLIGHTLY BELOW
THE SEASONAL AVERAGES.
&&
.AVIATION...04/06Z
ISSUED AT 1206 AM CDT FRI SEP 3 2015
ELEVATED CONVECTION CONTINUES TO WEAKLY MAINTAIN ITSELF NEAR
KALO/KMCW/KOTM AND EITHER VCSH OR VCTS WORDING HAS BEEN ADDED AS
APPROPRIATE. ALTHOUGH CONDITIONS FOR RADIATION FOG ARE STILL
SOMEWHAT FAVORABLE...HAVE INCREASED VSBYS TO IFR AT KMCW WITH MORE
MID CLOUDINESS THAN PREVIOUSLY ANTICIPATED POTENTIALLY HOLDING
THINGS BACK. OTHERWISE EXPECT VFR CONDITIONS WITH SCT/BKN MID OR
HIGH LEVEL CLOUDINESS THROUGH MUCH OF FRI AND FRI EVENING.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...SMALL
SHORT TERM...PODRAZIK
LONG TERM...BEERENDS
AVIATION...SMALL
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
136 AM EDT FRI SEP 4 2015
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 356 PM EDT THU SEP 3 2015
WV IMAGERY AND RAP ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH ALONG
THE WEST COAST AND A DOWNSTREAM RIDGE FROM TEH SRN PLAINS INTO THE
UPPER MS VALLEY. A SHORTWAVE TROUGH OVER LOWER MI...ON THE FORWARD
FLANK OF THE RIDGE...WAS VERY SLOWLY EDING TO THE SE. AT THE SFC...A
RIDGE EXTENDED FROM QUEBEC AND NRN ONTARIO INTO LAKE SUPERIOR
RESULTING IN LIGHT E TO NE FLOW THROUGH UPPER MI. VIS LOOP SHOWED
MOSTLY SUNNY SKIES ACROSS THE NORTH WITH SCT-BKN CU INLAND CNTRL.
TONIGHT...WITH THE LOSS OF DAYTIME HEATING...THE CU WILL FADE
LEAVING MOSTLY CLEAR SKIES. HOWEVER...SOME MID CLOUS AROUND THD
PERSISTENT LOW MAY MOVE BACK INTO THE SE. GIVEN DEWPOINTS IN LOWER
60S...RADIATIONAL COOLING SHOULD DROP MINS TO AROUND 60...COOLEST
OVER THE INLAND WEST HALF. SO...EXPECT AREAS OF FOG ARE LIKELY TO
DEVELOP...ESPECIALLY CNTRL.
FRI...ALTHOUGH THE LOWER MI MID LEVEL LOW SHOULD STILL
LINGER...UPPER MI WILL REMAIN UNDER THE INFLUENCE OF THE SFC RIDGE
WITH MOSTLY SUNNY SKIES AFTER THE MORNING FOG OR LOW CLOUDS BURN
OFF. WITH 850 MB TEMPS AROUND 15C...TEMPS SHOULD CLIMB TO AROUND
80...WITH LOWER READINGS ALONG THE GREAT LAKES.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 317 PM EDT THU SEP 3 2015
MAINLY FOCUSED ON SHOWER AND THUNDERSTORM COVERAGE/INTENSITY SAT
NIGHT INTO MONDAY AND ON CONTINUED HOT/HUMID CONDITIONS SAT AND SUN.
FRI NIGHT LOOKS DRY FOR MOST PART...BUT THERE IS A SLIGHT CHANCE OF
SHOWERS AND THUNDERSTORMS OVER THE W A SHORTWAVE ENERGY MOVES W OF
THE CWA IN THE SW FLOW ALOFT. A SIMILAR SETUP ON SAT...BUT GREATER
CHANCES OF PRECIP OVER THE W. COULD SEE SOME STRONG TO POSSIBLY
SEVERE STORMS...IF CONVECTION DOES DEVELOP...DUE TO 1000-2000 J/KG
OF MUCAPE. 0-6KM SHEAR WILL BE ON THE WEAK SIDE SAT AT ONLY AROUND
20KTS...WHICH LIMITS ORGANIZED SEVERE POTENTIAL.
THE 12Z/03 GFS IS AN OUTLIER FOR SAT NIGHT IN SHOWING PRECIP OVER
THE CENTRAL CWA. THINK THAT MOST OF THE AREA WILL STAY DRY SAT
NIGHT...WITH THE W POSSIBLY SEEING SOME CONVECTION. PRECIP LOOKS TO
STAY OVER THE W HALF ON SUN AS A STRONGER SHORTWAVE MOVES TO THE W.
WIND SHEAR WILL BE GREATER SUN...WITH 0-6KM BULK VALUES AROUND
30KTS...BUT MUCAPES WILL ONLY BE 1000-1500J/KG. TEMPS WILL BE
WARMEST ON SUN AS 850MB TEMPS WILL BE 20-22C...PROMOTING WARMEST
TEMPS AROUND 90 IN DOWNSLOPING AREAS OF NCENTRAL UPPER MI NEAR LAKE
SUPERIOR.
THE COLD FRONT FROM A LOW PRESSURE SYSTEM MOVING ACROSS SRN CANADA
WILL PASS THROUGH THE AREA SUN NIGHT INTO MON MORNING...WHICH WILL
MEAN LIMITED INSTABILITY AND MINIMAL SEVERE POTENTIAL. COVERAGE OF
CONVECTION LOOKS GOOD...WITH MOST LOCATIONS SEEING SOME PRECIP.
MON WILL SEE CLEARING SKIES AND PRECIP EXITING E. THE AIRMASS WILL
BECOME COOLER AND DRIER...BUT 850MB TEMPS ONLY DROP INTO THE MID
TEENS C BY LATE MON. THIS SHOULD RESULT IN HIGHS FROM THE MID 70S TO
LOW 80S.
LOTS OF UNCERTAINTY MID TO LATE NEXT WEEK AS DETAILS OF A TROUGH
DROPPING INTO THE REGION ARE HARD TO PIN DOWN. DOES LOOK COOLER WITH
AT LEAST A SLIGHT CHANCE OF PRECIP.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 136 AM EDT FRI SEP 4 2015
VFR CONDITIONS WILL PREVAIL INITIALLY AT KIWD/KCMX/KSAW. SINCE
DAYTIME HEATING YESTERDAY HELPED MIX OUT SOME OF THE LOW-LEVEL
MOISTURE AND SINCE WINDS JUST OFF THE SFC WILL BE A LITTLE STRONGER
OVERNIGHT THAN IN RECENT NIGHTS...FOG SHOULD NOT BE AS
DENSE/WIDESPREAD AS RECENT NIGHTS. IN ADDITION...SINCE MARINE FOG
HAS CLEARED OFF MOST OF LAKE SUPERIOR AND NORTHERN LAKE MICHIGAN...
ADVECTION OF MARINE FOG WON`T BE A CONTRIBUTOR TO POOR CONDITIONS.
THUS...IT STILL APPEARS FOG OVERNIGHT SHOULDN`T DROP VIS BLO MVFR AT
KCMX/KSAW. HOWEVER...NOT OUT OF THE QUESTION THAT THERE COULD BE A
PERIOD OF IFR AROUND DAYBREAK...ESPECIALLY AT KSAW. LIGHT DOWNSLOPE
WIND AT KIWD MAY WORK TO KEEP THAT TERMINAL VFR THRU THE NIGHT. VFR
CONDITIONS ARE EXPECTED AT ALL TERMINALS FROM MID MORNING INTO AT
LEAST THE EARLY EVENING. FOG WILL PROBABLY MAKE A RETURN NEAR OR
JUST BEYOND THIS FCST PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 356 PM EDT THU SEP 3 2015
AREAS OF FOG PERSISTED ACROSS THE WESTERN THIRD OF THE LAKE AND IS
EXPECTED TO LINGER INTO FRI WITH NE FLOW CONTINUING.
OTHERWISE...NORTHEAST WINDS OF 10-15KT WILL CONTINUE TODAY WITH 1-3
FT WAVES ACROSS THE WEST. THE NEXT CHANCE FOR WINDS GREATER THAN
20KT WILL BE SUNDAY INTO MONDAY AS THE NEXT SYSTEM APPROACHES FROM
THE WEST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...ROLFSON
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1222 AM EDT FRI SEP 4 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 330 PM EDT THU SEP 3 2015
SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE ACROSS LOWER
MICHIGAN THROUGH SATURDAY. THE CLOUDS AND SHOWERS WILL HOLD HIGHS
AROUND 80 FRIDAY BEFORE THE TEMPERATURE CLIMBS BACK TO THE MID 80S
FOR THE REMAINDER OF THE HOLIDAY WEEKEND. COOLER WEATHER IS EXPECTED
BY THE MIDDLE OF NEXT WEEK.
&&
.UPDATE...
ISSUED AT 838 PM EDT THU SEP 3 2015
I UPDATED OUR FORECAST AND GRIDS TO DROP THE MENTION OF
PRECIPITATION OVER MOST OF OUR CWA TONIGHT. AS I SEE IT THE
CONVECTIVE LINE CONTINUES TO SINK SOUTH WITH TIME AND SHOULD BE
OUT OF OUR CWA TOTALLY BY MIDNIGHT. THE RAP MODEL SHOWS THE 700 MB
LOW...CURRENTLY CENTERED NEAR LAKE HURON BY APN...MOVES SLOWLY
WESTWARD...REACHING TO NEAR TVC BY MORNING. THAT KEEPS MOST OF OUR
CWA IN THE DRY WESTERLY FLOW ALL NIGHT LONG. THE DEEP MOISTURE IS
EAST OF LANSING BY 9 PM. THE MOST UNSTABLE CAPE ON THE RAP13
MODEL DROPS SOUTH OVER TIME TOO... WHICH GOES ALONG WITH THE IDEA
OF NO SIGNIFICANT CONVECTION TONIGHT. ONLY AREAS NEAR THE 700 MB
LOW MAY SEE SOME LIGHT WRAP AROUND RAIN SHOWERS (NEAR AND NORTH OF
ROUTE 10).
AS FOR FOG DEVELOPING TONIGHT...THIS COULD BE A SIGNIFICANT
FORECAST ISSUE. THERE IS AN AREA OF THICK LOW CLOUDS DROPPING
SOUTH TO NEAR I-96...AS 0F 8 PM THIS EVENING. DEPENDING ON JUST
HOW FAR SOUTH THEY GET WILL DECIDE HOW DENSE THE FOG GETS TONIGHT.
WITH ALL THE RAIN TODAY AND LIGHT WINDS IF THE SKIES STAYED MOSTLY
CLEAR WE COULD BE LOOKING AT DENSE FOG BY SUNRISE. LIKELY IF THIS
HAPPENS IT WOULD BE NEAR I-94.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 330 PM EDT THU SEP 3 2015
FORECAST CONCERNS DEAL WITH THE CONVECTIVE POTENTIAL THROUGH
SATURDAY.
RADAR IMAGERY SHOWS A COUPLE OF BROKEN LINES OF CONVECTION. THE
FIRST EXTENDS FROM MOUNT PLEASANT WEST TO NEWAYGO COUNTY. THE SECOND
IS FARTHER SOUTH FROM NEAR ST JOHNS TO MIDDLEVILLE. THE SOUTHERN
LINE APPEARS TO BE NEAR A WEAK COLD FRONT THAT IS WASHING OUT.
FARTHER NORTH A WELL DEFINED CIRCULATION ASSOCIATED WITH AN UPPER
LOW THAT WILL LINGER OVER LOWER MICHIGAN THROUGH SATURDAY. SBCAPE
AROUND 2500 J/KG COUPLED WITH SHEAR AROUND 30 KTS IS ENABLING A FEW
STORMS TO BECOME ORGANIZED. AS THE SUN SETS WE/LL LOSE SOME
INSTABILITY AND THE CONVECTION SHOULD WANE A BIT. HOWEVER THE UPPER
LOW/TROUGH WILL LINGER OVER THE CWA THROUGH SATURDAY. SHEAR VALUES
AROUND 15KTS ARE PROGD FRIDAY ACROSS THE CWA SO WE DON/T ANTICIPATE
SVR STORMS BUT CAN`T RULE OUT A STRONG ONE OR TWO DUE TO DECENT
INSTABILITY.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 330 PM EDT THU SEP 3 2015 IMPACT WEATHER IN THE EXTENDED
PERIOD CENTERS AROUND THE SLOW MOVING FRONT THAT MAY BRING COPIOUS
RAINS FROM MONDAY TO EARLY WEDNESDAY.
ONLY A FEW TWEAKS WERE MADE TO THE BLENDED FORECAST...MAINLY TO SLOW
THE FRONT DOWN A BIT EARLY IN THE WEEK PER THE SLOWER 12Z ECMWF THEN
END THE CHANCE FOR POPS LATE WEDNESDAY WHICH THE 12Z GUIDANCE AGREES
ON. GIVEN THE LONG DURATION AND HIGH PWATS...WOULD NOT BE SURPRISED
TO SEE WIDESPREAD 2 TO 3 INCH RAINFALL FROM MONDAY TO EARLY
WEDNESDAY.
TEMPERATURES ON MONDAY WILL BE TRICKY AS HIGH COULD BE ANYWHERE FROM
AROUND 80 TO NEAR 90 DEPENDING ON HOW EXTENSIVE THE CLOUDS ARE. WENT
MIDDLE OF THE ROAD FOR NOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1212 AM EDT FRI SEP 4 2015
TRENDS WILL BE MONITORED FOR FOG DEVELOPMENT NOW THROUGH ABOUT
13Z. CURRENTLY THINKING THE LOW CLOUDS WILL BE MORE OF A PROBLEM
THAN FOG DEVELOPMENT FOR SITES LIKE MKG...GRR...AZO...AND BTL.
MODEL SOUNDINGS ARE NOT BULLISH ON FOG DEVELOPMENT AND EVEN THE
HOURLY LAMP GUIDANCE PRODUCTS ARE BACKING OFF A BIT ON THE VIS
REDUCTIONS. THAT SAID...THERE ARE POCKETS OF FOG NORTH OF LAN
WHERE BREAKS IN THE CLOUDS HAVE OCCURRED. WILL NEED TO KEEP TRACK
OF THE BREAKS OVERNIGHT. LOW CIGS LOOK QUITE LIKELY FOR MOST
LOCATIONS...PROBABLY GETTING DOWN TO A COUPLE HUNDRED FEET. WILL
STILL MENTION SOME LIGHT FOG FOR THE TAFS TO KEEP CONSISTENCY WITH
PREVIOUS THINKING...THOUGH WILL KEEP ABOVE 1/2SM FOR NOW.
&&
.MARINE...
ISSUED AT 330 PM EDT THU SEP 3 2015
WINDS AND WAVES WILL REMAIN ON THE LIGHT SIDE TONIGHT AND FRIDAY DUE
TO THE WEAK PRESSURE GRADIENT. LIGHT NORTH WINDS TONIGHT WILL BECOME
ONSHORE FRIDAY. SCATTERED THUNDERSTORMS ARE POSSIBLE THROUGH
SATURDAY.
&&
.HYDROLOGY...
ISSUED AT 1110 AM EDT THU SEP 3 2015
NO IMMEDIATE CONCERNS TO BE AWARE OF TODAY REGARDING RIVER
FLOODING.
HEAVY RAINFALL ASSOCIATED WITH THUNDERSTORM ACTIVITY WILL QUICKLY
PASS THROUGH THE AREA THIS MORNING AND THROUGH EARLY AFTERNOON.
PONDING MAY OCCUR ON ROADWAYS AND LOW LYING AREAS IN AND AROUND
THE HEAVIER RAINFALL. MUCH OF THE HEAVIER ACTIVITY WILL VACATE
THE REGION BY MID AFTERNOON.
THE NEXT 7 DAYS REMAINS ACTIVE AND INCLUDES MULTIPLE CHANCES FOR
RAIN. 7 DAY AREA AVERAGE RAINFALL OF ONE TO TWO INCHES IS POSSIBLE
WITH LOCALLY HIGHER AMOUNTS IN THE VICINITY OF THUNDERSTORMS.
RECENT DRY WEATHER AND LOW RIVER LEVELS...COUPLED WITH THE
PIECEWISE FASHION OF THE RAINFALL...SHOULD ALLOW FOR THE GROUND TO
SOAK UP MUCH OF THE ONSET OF MOISTURE. RUNOFF THEREAFTER IS
LIKELY TO BE HANDLED WELL BY RIVERS...AS THEY HAVE PLENTY OF ROOM
TO TAKE ON ADDITIONAL WATER.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...04
SHORT TERM...04
LONG TERM...OSTUNO
AVIATION...HOVING
HYDROLOGY...JAM
MARINE...04
AREA FORECAST DISCUSSION
NWS RALEIGH NC
127 AM EDT FRI SEP 4 2015
.SYNOPSIS...AN UPPER LEVEL DISTURBANCE WILL AMPLIFY ACROSS CENTRAL
TODAY. MEANWHILE AT THE SURFACE...A BACKDOOR COLD FRONT WILL
APPROACH FROM THE NORTH LATE TODAY...THEN PUSH SOUTHWARD THROUGH THE
AREA TONIGHT...BEFORE SETTLING TO OUR SOUTH ON SATURDAY. HIGH
PRESSURE WILL EXTEND INTO THE REGION FROM THE NORTH OVER THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1050 PM THURSDAY...
EVENING WATER VAPOR IMAGERY DEPICTED AN ELONGATED AXIS OF SHEAR
VORTICITY STRETCHING FROM WESTERN NC NORTHWESTWARD TO A WELL-DEFINED
SHORTWAVE TROUGH OVER WISCONSIN. NWP GUIDANCE INDICATES THE
VORTICITY AXIS WILL BECOME MORE CONCENTRIC WITH TIME AND
SOUTHEASTWARD EXTENT/NEAR THE BASE OF THE PARENT TROUGH AXIS OVER
THE CAROLINAS...ULTIMATELY CULMINATING IN A CLOSED UPPER LOW AND
POCKET OF -9 TO -10 C 500 MB TEMPERATURES OVER CENTRAL NC DURING THE
DAY FRI. THE PRECEDING ASSOCIATED DYNAMIC FORCING FOR ASCENT IS
FORECAST TO SPREAD EAST OF THE APPALACHIANS AND ACROSS CENTRAL VA
AND CENTRAL NC BETWEEN 06-12Z. SHOWERS HAVE BEEN PERCOLATING OVER
WESTERN NC DURING THE PAST COUPLE OF HOURS (AFTER SUNSET/DURING A
TIME THAT SOLELY-DIURNALLY-DRIVEN CONVECTION SHOULD BE DIMINISHING);
AND THIS ACTIVITY IS PRESUMABLY INDICATIVE OF THE INFLUENCE OF THE
AMPLIFYING VORT MAX. THAT FORCING...IN CONJUNCTION WITH LOW LEVEL
CONVERGENCE ALONG A LEE SURFACE TROUGH THAT NEARLY PERFECTLY BISECTS
THE RAH CWFA FROM NNE TO SSW THIS EVENING...MAY YET FOCUS SOME
ISOLATED SHOWERS OVERNIGHT...MAINLY ALONG AND EAST OF THE TROUGH
AXIS/WHERE LOW LEVEL MOISTURE AND ASSOCIATED INSTABILITY FIELDS
ARE/WILL CONTINUE TO BE RELATIVELY MAXIMIZED.
OTHERWISE...SURFACE VISIBILITY IS ALREADY DECREASING ACROSS CENTRAL
NC...AND BOTH STATISTICAL GUIDANCE AND HRRR VISIBILITY FORECASTS
SUGGEST VISIBILITY RESTRICTIONS WILL CONTINUE TO EXPAND AND LOWER IN
A RELATIVELY CALM...CLEAR...AND MOIST (IN THE BOUNDARY LAYER)
ENVIRONMENT OVER CENTRAL NC OVERNIGHT. LOWS AGAIN IN THE UPPER 60S
TO LOWER 70S.
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 325 PM THURSDAY...
OUR BEST SHOT AT SCATTERED TO NUMEROUS SHOWERS AND STORMS WILL BE
LATE FRI INTO FRI NIGHT... WITH SEVERAL FAVORABLE FACTORS IN PLAY.
FIRST... MODELS DEPICT A POCKET OF ABOVE-NORMAL PW SLIDING SOUTHWARD
FROM VA INTO/THROUGH CENTRAL NC TOMORROW... IN CONJUNCTION WITH WEAK
DPVA SPREADING IN FROM THE NW AND NE AND IMPROVING UPPER DIVERGENCE
FROM THE NORTH... ALL AHEAD OF THE INCOMING BACKDOOR COLD FRONT. THE
LARGE-SCALE MODELS INCLUDING THE NAM/GFS/ECMWF/SREF ARE IN AGREEMENT
ON CONVECTION DEVELOPING DURING THE EARLY TO MID AFTERNOON OVER
CENTRAL NC... FOCUSING THE BEST COVERAGE AND HIGHEST AMOUNTS OVER
THE FAR NW PIEDMONT. GIVEN THE EXPECTED MID-UPPER LEVEL DYNAMIC
CONTRIBUTIONS TO ASCENT... DESTABILIZATION WITH GOOD HEATING DURING
THE DAY... AND RISING MOISTURE THROUGH THE COLUMN... CONVECTIVE
COVERAGE LOOKS SUFFICIENT TO RAISE POPS A BIT... TO LIKELY IN THE NW
CWA WITH GOOD CHANCES ELSEWHERE FOR NOW (ALTHOUGH THESE MAY GO UP TO
LIKELY HERE AS WELL IN LATER FORECASTS IF TRENDS HOLD). THE WEAK
DEEP LAYER SHEAR SHOULD LIMIT STORM STRENGTH... ALTHOUGH THE PROFILE
AND DCAPE NOTED ON NAM FORECAST SOUNDINGS WOULD SUGGEST A MARGINAL
WIND THREAT. THE ANTICIPATED SLOW MOVEMENT WITH HIGH WATER CONTENT
WILL BRING A RISK OF SLOW-MOVING STORMS GENERATING URBAN FLOODING.
EXPECT HIGHS OF 90-95 WITH DECENT PREFRONTAL HEATING AND CONTINUED
ABOVE NORMAL THICKNESSES. POPS SHOULD TREND DOWNWARD AFTER NIGHTFALL
WITH LOSS OF INSOLATION... HOWEVER WITH LOW LEVEL CONFLUENT FLOW
NEAR THE BACKDOOR FRONT AND INCREASED ATLANTIC-SOURCE FEED WITH
PERSISTENT UPPER DIVERGENCE OVERNIGHT... WILL KEEP A MENTION OF
SCATTERED SHOWERS AND STORMS THROUGH THE NIGHT... WITH THE BEST
CHANCES WEST. LOWS 67-71. -GIH
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
AS OF 150 PM THURSDAY...
COOLER TEMPERATURES EXPECTED FOR MUCH OF THE LONG TERM AS THE COLD
FRONT THAT IS PROGGED TO COME THROUGH FRIDAY NIGHT WILL BRING A
CHANGE IN AIRMASS FROM THE NORTHEAST. WITH THIS WILL COME A GREATER
FETCH OF MOISTURE FROM OFFSHORE...DRIVEN BY SEVERAL SHORTWAVE
IMPULSES THAT ARE EXPECTED TO MOVE INTO THE STATE DURING THE WEEKEND
AND INTO EARLY NEXT WEEK.
FOR THE WEEKEND...THE GREATEST THREAT FOR RAIN WILL BE IN THE WEST
ON SATURDAY AS THE FRONT MOVES THROUGH AND A CAD-LIKE SCENARIO SETS
UP. AS THE WEEKEND PROGRESSES HOWEVER...AN INVERTED TROUGH ALONG THE
EAST COAST WILL SHARPEN AND THUS BRING A MORE NORTHERLY COMPONENT TO
THE WIND AND SHUT OFFSHORE MOISTURE FEED INTO THE NW PIEDMONT AND
INSTEAD BEGIN TO FOCUS THE BEST CHANCE FOR CONVECTION OVER THE
EASTERN PART OF THE STATE. THUS RAIN CHANCES FOR SUNDAY WILL BE
BETTER IN THE EAST THAN IN THE WEST. THIS PATTERN WILL CONTINUE INTO
LABOR DAY WITH SOUTHEASTERN COUNTIES HAVING THE BEST CHANCE FOR
SHOWERS AND THUNDERSTORMS. HIGHS IN THE LOW TO MID 80S FOR THIS
PERIOD WITH THE POTENTIAL FOR SOME UPPER 70S IN THE NW IF CLOUD
COVER LOCKS IN.
THE BERMUDA HIGH BEGINS TO TAKE BACK OVER FOR MIDWEEK AND THE
SURFACE HIGH OVER OUR AREA AND THE INVERTED TROUGH WILL BEGIN TO
BREAK DOWN. THIS WILL SEE A RETURN TO WARMER TEMPERATURES...ALTHOUGH
GRADUALLY...WITH DIURNAL CHANCES FOR SHOWERS AND ISOLATED
THUNDERSTORMS THROUGH THURSDAY. AT THIS TIME...ANY THUNDERSTORMS
THAT DO OCCUR EITHER THIS WEEKEND OR NEXT WEEK ARE NOT EXPECTED TO
BE SEVERE...BUT A FEW STRONG STORMS CANNOT BE RULED OUT.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 120 AM FRIDAY...
24 HR TAF PERIOD: EARLY MORNING FOG AND LOW STRATUS DEVELOPMENT IS
UNDERWAY ACROSS CENTRAL NC... WITH LOCATIONS AGAIN ACROSS THE
NORTHEAST PIEDMONT AND NORTHERN AND CENTRAL COASTAL EXPECTED TO SEE
THE MOST COVERAGE AND IFR/LIFR CONDITIONS... THANKS IN PART TO MOIST
SOILS FROM THE CONVECTION LATE WEDNESDAY AND EARLY THURSDAY MORNING.
THUS... AGAIN THINK IFR/LIFR FOG AND LOW STRATUS WILL DEVELOP AT
KRWI AND KRDU THIS MORNING... WITH GENERALLY MVFR VISBYS AT
KFAY/KGSO/KINT. ANY FOG AND STRATUS THAT DEVELOPS EARLY THIS MORNING
SHOULD LIFT WITHIN A FEW HOURS OF SUNRISE AGAIN... WITH SKIES
BECOMING MOSTLY TO PARTLY SUNNY BY MID MORNING. HOWEVER... AS A
MID/UPPER LEVEL DISTURBANCE CONTINUES TO MOVE INTO THE REGION
COUPLED WITH THE APPROACH OF A BACKDOOR COLD FRONT... EXPECT CLOUD
COVER SHOULD THICKEN THIS AFTERNOON INTO THE EVENING... WITH
SCATTERED TO POTENTIALLY NUMEROUS SHOWERS AND STORMS DEVELOPING.
THUS... HAVE ADDED A PROB30 GROUP FOR THE POTENTIAL FOR CONVECTION
THIS AFTERNOON AND EVENING AT ALL TAF SITES. ANY STORMS THAT DEVELOP
WILL HAVE THE POTENTIAL TO PRODUCE AT LEAST IFR CONDITIONS IN HEAVY
RAIN... ALONG WITH GUSTY WINDS.
OUTLOOK: LINGERING SHOWERS AND EVEN SOME ISOLATED STORMS MAY
CONTINUE INTO THE EARLY MORNING HOURS OF SATURDAY... AS THE FRONT
MOVES THROUGH THE AREA... WITH LOCATIONS ACROSS THE WESTERN PIEDMONT
STANDING THE BEST CHANCE AS SEEING LINGERING CONVECTION (KGSO/KINT).
MORE WIDELY SCATTERED CONVECTION IS POSSIBLE DURING THE AFTERNOON
AND EVENING ON SATURDAY AND SUNDAY WITH A DECREASE IN COVERAGE AND A
FOCUS TOWARD THE COASTAL PLAIN ON MONDAY AND TUESDAY. LATE NIGHT AND
MORNING FOG AND STRATUS WITH POTENTIALLY SIGNIFICANT RESTRICTIONS
APPEAR PROBABLE ON SATURDAY AND SUNDAY MORNINGS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BSD/26
NEAR TERM...26
SHORT TERM...HARTFIELD
LONG TERM...ELLIS
AVIATION...BSD/BLAES
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
223 AM EDT FRI SEP 4 2015
.SYNOPSIS...
UNSTABLE AIRMASS CONTINUES INTO FRIDAY. CONVECTION MOST COMMON
DURING THE AFTERNOON AND EVENING...BUT COULD ISOLATED AREAS COULD
LINGER OVERNIGHTS. SOUTHEAST FLOW INCREASES FRIDAY NIGHT INTO SATURDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
INCREASED POPS N WHILE DRYING OUT SWRN PORTIONS OF THE FCST AREA
OVERNIGHT..GIVEN THUNDERSTORM COMPLEX DRIFTING SWD INTO THE
MIDDLE OHIO VALLEY OVERNIGHT WAS LOCATED RIGHT IN THE DIFFLUENT
ZONE JUST SE OF AN UPPER LEVEL LOW OVER LOWER MICHIGAN.
PREV DISCN...
LOCAL DOWNPOURS VERSUS THE HEAT THURSDAY AFTERNOON. ANOTHER NIGHT
THAT WE CAN NOT REMOVE THE CHANCE OF RAIN TOTALLY. RAP SHOWS A
WEAK VORT MAX IN CENTRAL OHIO DRIFTING EAST AND SOUTH.
DESPITE THE LINGERING CONVECTION...STILL HAVE AREAS OF FOG
FORMING...ESPECIALLY IN AREAS THAT HAD RAIN. YET...THE LINGERING
PATCHES OF CLOUDS COULD INTERFERE WITH THE FOG FORMATION. SO
ANOTHER HARD HOUR BY HOUR FORECAST CONCERNING THE FOG FOR 06Z TO
12Z FRIDAY.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
STAGNANT PATTERN THIS WEEKEND AMID UPPER LEVEL RIDGING OVER THE E
CONUS. THERE IS JUST ENOUGH OF A WEAKNESS OVER THE REGION THAT
COMBINED WITH AFTERNOON HEATING...THERE SHOULD BE DIURNAL POPCORN
SHRA/TSRA MAXIMIZED OVER THE MOUNTAINS. STILL...LOW POPS WITH
ISOLATED COVERAGE. TEMPS WILL GENERALLY RUN 5 TO 10 DEGREES ABOVE
NORMAL AND DEWPOINTS ON THE MUGGY SIDE.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
MORE OF THE SAME THROUGH WEDNESDAY...HOT AND MUGGY CONDITIONS WITH
JUST AN ISOLATED SHRA/TSRA. PATTERN FINALLY BEGINS TO BREAK TOWARD
THURSDAY WITH FALLING HEIGHTS AMID A TRANSITION MORE INTO A E
CONUS TROF. THE COLD FRONT THAT WILL MARK THIS TRANSITION LOOKS TO
CROSS LONG ABOUT THURSDAY. IT IS LOOKING LIKE A WAVE WILL DEVELOP
ALONG THE FRONT WITH A GOOD SHOT A MUCH NEEDED RAIN OVER THE
AREA...PARTICULARLY ALONG THE OH RIVER.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
VALLEY FOG FORMATION WAS ALREADY WELL UNDERWAY...BUT A
THUNDERSTORM COMPLEX MOVING SEWD INTO THE MIDDLE OHIO VALLEY MAY
CAUSE THE FOG TO BREAK UP THERE...AND THE CHANCE FOR A
THUNDERSTORM IMPACTING AN AIRPORT DIRECTLY DEPENDS UPON TO WHAT
DEGREE THE COMPLEX HOLDS TOGETHER OVERNIGHT. PKB AND PERHAPS CKB
ARE MORE LIKELY TO BE IMPACTED OVERNIGHT...VERSUS POINTS FARTHER
TO THE S AND E.
DAYBREAK WILL BRING AN END TO BOTH FOG AND THUNDER CONCERNS BY MID
MORNING...BUT SCATTERED AFTERNOON CONVECTION WILL FIRE UP AGAIN
FRI AFTERNOON...AS AN UPPER LEVEL DISTURBANCE OVER OHIO
OVERNIGHT...DRIFTS OVER WV FRI.
FRI NT WILL BE ANOTHER TOUGH CALL. ON THE ONE HAND...AFTERNOON AND
EVENING RAINFALL GREATLY INCREASES THE CHANCE OF AND HASTENS THE
TIMING OF THE FORMATION OF OVERNIGHT FOG. ON THE OTHER
HAND...OVERNIGHT CONVECTION INTERFERES WITH DENSE FOG.
MAINLY CALM SFC WIND OVERNIGHT WILL BE LIGHT AND VARIABLE...MAINLY
N...ON FRI...AND THEN LIGHT AND VARIABLE FRI NT. LIGHT N TO NE
FLOW ALOFT OVERNIGHT AND FRI WILL BECOME LIGHT NE TO E FRI NT.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SATURDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING AND COVERAGE OF FOG OVERNIGHT MAY
VARY FROM FORECAST. MAY NEED AMENDMENTS AND TEMPOS IF STORMS
FORM/MOVE TOWARDS TERMINALS AT ANYTIME.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE FRI 09/04/15
UTC 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14
EDT 1HRLY 23 00 01 02 03 04 05 06 07 08 09 10
CRW CONSISTENCY H H M M M L L L L L M M
HTS CONSISTENCY H H H M M L L L L L H M
BKW CONSISTENCY H H H H H H H H H H H M
EKN CONSISTENCY M M L L L L L L L L M M
PKB CONSISTENCY M M M L L L L L L L M M
CKB CONSISTENCY H M M L L L L L L L M M
AFTER 06Z SATURDAY...
IFR POSSIBLE IN VALLEY FOG OVERNIGHT FRIDAY NIGHT INTO SATURDAY
MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...30/26
NEAR TERM...KTB/TRM
SHORT TERM...30
LONG TERM...30
AVIATION...TRM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
913 AM CDT FRI SEP 4 2015
.UPDATE...
ISSUED AT 902 AM CDT FRI SEP 4 2015
UPDATE TO BLEND OBSERVED RADAR TRENDS TO A TIME LAGGED ENSEMBLE OF
THE 10-12 UTC HRRR ITERATIONS WHICH HAVE A GOOD HANDLE OF ONGOING
CONVECTION THIS MORNING. SPC HAS MAINTAINED THE MARGINAL RISK FOR
SEVERE STORMS FOR THE TURTLE MOUNTAINS THROUGH THE JAMES RIVER
VALLEY AND POINTS EAST THIS AFTERNOON. THE 13 UTC RAP FORECAST
DEPICTS 1500-2000 J/KG OF ML CAPE AND 20-25 KTS OF DEEP LAYER
SHEAR THIS AFTERNOON ACROSS THE AFOREMENTIONED AREAS...SUPPORTING
THE MARGINAL RISK FOR POSSIBLY A SEVERE STORM OR TWO.
HOWEVER...THE RAP ALSO PROPAGATES THE MAIN FORCING MECHANISM OF
THE SHORTWAVE ACROSS CENTRAL SOUTH DAKOTA THIS MORNING INTO
NORTHEAST NORTH DAKOTA LATE THIS AFTERNOON. THUS...THE TIMING OF
THE WAVE SUGGESTS THE BEST POTENTIAL FOR STRONG TO SEVERE STORMS MAY
RESIDE NORTHEAST OF THE CWA.
UPDATE ISSUED AT 628 AM CDT FRI SEP 4 2015
SHOWERS CONTINUE TO LIFT SOUTH TO NORTH OVER THE AREA THIS
MORNING...WITH THE GREATEST COVERAGE AT THIS TIME OVER FAR
WESTERN NORTH DAKOTA. ANOTHER AREA CONTINUES TO DEVELOP OVER
PORTIONS OF SOUTH CENTRAL NORTH DAKOTA...WHILE A BROAD AREA OVER
CENTRAL SOUTH DAKOTA CONTINUES TO LIFT TOWARDS OUR REGION. FOR THE
MORNING UPDATE...HAVE TRIED TO TIME OUT THE MOTION/ARRIVAL OF
THESE STORMS BASED ON CURRENT TRENDS AND LATEST HRRR GUIDANCE AND
HAVE ADJUSTED POPS ACCORDINGLY. UPDATES HAVE BEEN SENT.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 423 AM CDT FRI SEP 4 2015
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE CHANCES FOR
SHOWERS AND THUNDERSTORMS THROUGH THE PERIOD. HEAVY RAIN POTENTIAL
FAR NORTHWEST THIS MORNING AND POSSIBLY ACROSS THE JAMES RIVER
VALLEY.
CURRENTLY...SOUTH-SOUTHWEST FLOW ALOFT. STRONG EMBEDDED S/WV
IMPULSE LIFTING ACROSS WESTERN SOUTH DAKOTA TOWARDS CENTRAL NORTH
DAKOTA RESULTING IN AN INCREASE IN COVERAGE AND INTENSITY IN
SHOWERS AND THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS THE
PAST FEW HOURS. THE MOST FAVORED AREAS WILL BE ALONG A QUASI-
STATIONARY FRONTAL BOUNDARY DRAPED FROM SOUTHWESTERN NORTH DAKOTA
NORTHEAST THROUGH THE TURTLE MOUNTAINS...AND ACROSS MY NORTHWEST
NEAR A POST FRONTAL AXIS. ANOMALOUS MOISTURE SURGING INTO THE
NORTHERN PLAINS WITH LATEST WATER VAPOR LOOP INDICATING A WELL
DEFINED MID/UPPER LEVEL MOISTURE FEED FROM TROPICAL STORM FRED
SOUTHWEST OF BAJA CALIFORNIA. WARM MID-ATMOSPHERIC PROFILE
SUGGESTS A MORE LOCALIZED HEAVY RAIN THREAT VERSUS WIDESPREAD.
WILL CONTINUE TO MONITOR.
AS MENTIONED ABOVE...AND AS HIGH RES AND LATEST NAM MODEL
SUGGEST...NORTHWESTERN NORTH DAKOTA AND THE JAMES RIVER VALLEY
LOOK HAVE THE GREATEST POTENTIAL AT THIS TIME FOR HEAVY RAINFALL.
VIGOROUS CONVECTION OVER SOUTHEASTERN SASKATCHEWAN SHOWING SOME
SIGNS OF DEVELOPING SOUTH INTO MY NORTHWEST. CONVECTIVE COMPLEX
OVER CENTRAL SOUTH DAKOTA MOVING NORTH WHICH LATEST NAM AND HRRR
BRING INTO THE JAMES RIVER BASIN 12-15Z OR SO. VERY UNSEASONABLE
HIGH DEWPOINT TEMPERATURES OUT THERE IN THE 60S TO LOW 70S
CENTRAL AND EAST.
EMBEDDED WAVE CONTINUES TO LIFT NORTH-NORTHEAST TODAY AND EXPECT
CLEARING SKIES AND DECREASING CHANCES FOR SHOWERS/THUNDERSTORMS
FROM SOUTH TO NORTH IN THE WAVE`S WAKE THIS AFTERNOON. LATEST SPC
OUTLOOK MOVED THE SLIGHT RISK AREA INTO MAINLY THE RED RIVER
VALLEY OF EASTERN NORTH DAKOTA...SO OPTED TO REMOVE SEVERE WORDING
IN OUR PRODUCTS. MODELS HINTING AT LOW LEVEL STRATUS/FOG DEVELOPING
TONIGHT WITH LOW LEVEL MOISTURE REMAINING HIGH COUPLED WITH
FORECAST RAINFALL TODAY.
NEXT STRONG EMBEDDED WAVE LIFTS NORTH-NORTHEAST LATE TONIGHT INTO
SATURDAY...WITH INCREASING POPS WEST LATE TONIGHT THEN SPREADING
EAST AND NORTH ACROSS THE REMAINDER OF THE STATE DURING THE DAY
SATURDAY.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 359 AM CDT FRI SEP 4 2015
UPPER LEVEL TROUGH CLOSES OFF TOWARDS NORTHERN MONTANA THROUGH THE
NIGHT ON SATURDAY WITH PRECIPITATION CHANCES SLOWLY TAPERING OFF
THROUGH THE NIGHT FROM SOUTH TO NORTH. ON SUNDAY...GREATEST
CHANCES WILL BE RESTRICTED TO NORTHERN PORTIONS OF THE AREA AS
UPPER LOW STARTS TO WORK ITS WAY TOWARDS THE EAST/NORTHEAST ACROSS
THE SOUTHERN PRAIRIE PROVINCES. DRY CONDITIONS EXPECTED OVER MOST
LOCATIONS BY SUNDAY NIGHT. BREEZY/WINDY CONDITIONS EXPECTED ON
SUNDAY AS SYSTEM BECOMES STACKED.
MAINLY DRY CONDITIONS EXPECTED ON MONDAY WITH COOLING TREND
CONTINUING AS LOW CONTINUES ITS TRACK NORTH OF THE AREA. THIS WILL
BRING CONTINUED BREEZY CONDITIONS OVER NORTHERN LOCATIONS. MAINLY
DRY CONDITIONS EXPECTED THROUGH MID-WEEK WITH A GRADUAL WARMING
TREND EXPECTED AS RIDGE BUILDS OVER WESTERN CONUS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 902 AM CDT FRI SEP 4 2015
PATCHY FOG AND IFR STRATUS POTENTIAL THROUGH MID MORNING WITH
VERY HIGH BOUNDARY LAYER MOISTURE ACROSS THE REGION. WESTERN
TERMINALS WILL SEE -SHRA AND VCTS NOW THROUGH MID
MORNING...SPREADING EAST MID MORNING THROUGH THE AFTERNOON. AT
LEAST PARTIAL CLEARING EXPECTED FROM SOUTH TO NORTH TODAY INTO
THIS EVENING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...NH
LONG TERM...JJS
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
633 AM CDT FRI SEP 4 2015
.UPDATE...
ISSUED AT 628 AM CDT FRI SEP 4 2015
SHOWERS CONTINUE TO LIFT SOUTH TO NORTH OVER THE AREA THIS
MORNING...WITH THE GREATEST COVERAGE AT THIS TIME OVER FAR
WESTERN NORTH DAKOTA. ANOTHER AREA CONTINUES TO DEVELOP OVER
PORTIONS OF SOUTH CENTRAL NORTH DAKOTA...WHILE A BROAD AREA OVER
CENTRAL SOUTH DAKOTA CONTINUES TO LIFT TOWARDS OUR REGION. FOR THE
MORNING UPDATE...HAVE TRIED TO TIME OUT THE MOTION/ARRIVAL OF
THESE STORMS BASED ON CURRENT TRENDS AND LATEST HRRR GUIDANCE AND
HAVE ADJUSTED POPS ACCORDINGLY. UPDATES HAVE BEEN SENT.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 423 AM CDT FRI SEP 4 2015
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE CHANCES FOR
SHOWERS AND THUNDERSTORMS THROUGH THE PERIOD. HEAVY RAIN POTENTIAL
FAR NORTHWEST THIS MORNING AND POSSIBLY ACROSS THE JAMES RIVER
VALLEY.
CURRENTLY...SOUTH-SOUTHWEST FLOW ALOFT. STRONG EMBEDDED S/WV
IMPULSE LIFTING ACROSS WESTERN SOUTH DAKOTA TOWARDS CENTRAL NORTH
DAKOTA RESULTING IN AN INCREASE IN COVERAGE AND INTENSITY IN
SHOWERS AND THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS THE
PAST FEW HOURS. THE MOST FAVORED AREAS WILL BE ALONG A QUASI-
STATIONARY FRONTAL BOUNDARY DRAPED FROM SOUTHWESTERN NORTH DAKOTA
NORTHEAST THROUGH THE TURTLE MOUNTAINS...AND ACROSS MY NORTHWEST
NEAR A POST FRONTAL AXIS. ANOMALOUS MOISTURE SURGING INTO THE
NORTHERN PLAINS WITH LATEST WATER VAPOR LOOP INDICATING A WELL
DEFINED MID/UPPER LEVEL MOISTURE FEED FROM TROPICAL STORM FRED
SOUTHWEST OF BAJA CALIFORNIA. WARM MID-ATMOSPHERIC PROFILE
SUGGESTS A MORE LOCALIZED HEAVY RAIN THREAT VERSUS WIDESPREAD.
WILL CONTINUE TO MONITOR.
AS MENTIONED ABOVE...AND AS HIGH RES AND LATEST NAM MODEL
SUGGEST...NORTHWESTERN NORTH DAKOTA AND THE JAMES RIVER VALLEY
LOOK HAVE THE GREATEST POTENTIAL AT THIS TIME FOR HEAVY RAINFALL.
VIGOROUS CONVECTION OVER SOUTHEASTERN SASKATCHEWAN SHOWING SOME
SIGNS OF DEVELOPING SOUTH INTO MY NORTHWEST. CONVECTIVE COMPLEX
OVER CENTRAL SOUTH DAKOTA MOVING NORTH WHICH LATEST NAM AND HRRR
BRING INTO THE JAMES RIVER BASIN 12-15Z OR SO. VERY UNSEASONABLE
HIGH DEWPOINT TEMPERATURES OUT THERE IN THE 60S TO LOW 70S
CENTRAL AND EAST.
EMBEDDED WAVE CONTINUES TO LIFT NORTH-NORTHEAST TODAY AND EXPECT
CLEARING SKIES AND DECREASING CHANCES FOR SHOWERS/THUNDERSTORMS
FROM SOUTH TO NORTH IN THE WAVE`S WAKE THIS AFTERNOON. LATEST SPC
OUTLOOK MOVED THE SLIGHT RISK AREA INTO MAINLY THE RED RIVER
VALLEY OF EASTERN NORTH DAKOTA...SO OPTED TO REMOVE SEVERE WORDING
IN OUR PRODUCTS. MODELS HINTING AT LOW LEVEL STRATUS/FOG DEVELOPING
TONIGHT WITH LOW LEVEL MOISTURE REMAINING HIGH COUPLED WITH
FORECAST RAINFALL TODAY.
NEXT STRONG EMBEDDED WAVE LIFTS NORTH-NORTHEAST LATE TONIGHT INTO
SATURDAY...WITH INCREASING POPS WEST LATE TONIGHT THEN SPREADING
EAST AND NORTH ACROSS THE REMAINDER OF THE STATE DURING THE DAY
SATURDAY.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 359 AM CDT FRI SEP 4 2015
UPPER LEVEL TROUGH CLOSES OFF TOWARDS NORTHERN MONTANA THROUGH THE
NIGHT ON SATURDAY WITH PRECIPITATION CHANCES SLOWLY TAPERING OFF
THROUGH THE NIGHT FROM SOUTH TO NORTH. ON SUNDAY...GREATEST
CHANCES WILL BE RESTRICTED TO NORTHERN PORTIONS OF THE AREA AS
UPPER LOW STARTS TO WORK ITS WAY TOWARDS THE EAST/NORTHEAST ACROSS
THE SOUTHERN PRAIRIE PROVINCES. DRY CONDITIONS EXPECTED OVER MOST
LOCATIONS BY SUNDAY NIGHT. BREEZY/WINDY CONDITIONS EXPECTED ON
SUNDAY AS SYSTEM BECOMES STACKED.
MAINLY DRY CONDITIONS EXPECTED ON MONDAY WITH COOLING TREND
CONTINUING AS LOW CONTINUES ITS TRACK NORTH OF THE AREA. THIS WILL
BRING CONTINUED BREEZY CONDITIONS OVER NORTHERN LOCATIONS. MAINLY
DRY CONDITIONS EXPECTED THROUGH MID-WEEK WITH A GRADUAL WARMING
TREND EXPECTED AS RIDGE BUILDS OVER WESTERN CONUS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 628 AM CDT FRI SEP 4 2015
PATCHY FOG AND LOW STRATUS POTENTIAL THROUGH MID MORNING WITH VERY
HIGH BOUNDARY LAYER MOISTURE ACROSS THE REGION. WESTERN TERMINALS
WILL SEE -SHRA AND VCTS NOW THROUGH MID MORNING...SPREADING EAST
MID MORNING THROUGH THE AFTERNOON. AT LEAST PARTIAL CLEARING
EXPECTED FROM SOUTH TO NORTH TODAY INTO THIS EVENING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JJS
SHORT TERM...NH
LONG TERM...JJS
AVIATION...NH
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
807 AM EDT FRI SEP 4 2015
.SYNOPSIS...
AN UPPER AIR DISTURBANCE OVER LOWER MICHIGAN WILL CONTINUE TO
DRIFT SOUTHEAST AND WEAKEN TODAY. A BROAD AREA OF HIGH PRESSURE
AT THE SURFACE AND ALOFT FROM THE MIDWEST TO EASTERN CANADA WILL
REMAIN NEARLY STATIONARY THROUGH LABOR DAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A NICE AREA OF RAIN CONTINUES TO DRIFT ACROSS THE CENTRAL PORTION
OF THE AREA. HEAVY RAIN CURRENTLY FALLING AT KCLE. HAVE BUMPED UP
PRECIP CHANCES A LITTLE FOR THE NEXT FEW HOURS IN THE EAST. WITH
ALL OF THE OUTFLOW BOUNDARIES FLOATING AROUND EXPECT TO CONTINUE
TO SEE NEW STORMS POPPING UP.
A PREVIOUS...SHOWERS AND THUNDERSTORMS CONTINUE TO MOVE AND
REDEVELOP ACROSS NORTH CENTRAL OHIO THIS MORNING. THERE HAS BEEN A
DECREASE IN INTENSITY AND LIGHTNING THE PAST COUPLE OF HOURS BUT
THE LATEST HRRR TAKES THIS AREA OF PRECIP ALL THE WAY TO THE PA
BORDER BY 12Z. WILL KEEP SCATTERED WORDING GOING THROUGH DAYBREAK
OR SO AND THEN BRIEFLY DIMINISH PRECIP CHANCES FOR THE MORNING
HOURS. MORE SHOWERS AND STORMS ARE EXPECTED THIS AFTERNOON. THE
00Z GUIDANCE...ESPECIALLY THE NAM IS SHOWING OVER 4000 J/KG CAPES
THIS AFTERNOON. AND...UNLIKE THE PREVIOUS COUPLE OF DAYS...BETTER
TRIGGERS IN THE FORM OF LEFT OVER BOUNDARIES FROM TONIGHT`S
CONVECTION WILL BE FLOATING AROUND TO KICK OFF NEW STORMS. TOUGH
TO TELL WHEN AND WHERE THE STORMS WILL INITIATE SO WILL KEEP A
GENERIC SCATTERED WORDING MOST OF THE DAY. IF I HAD TO GUESS I
WOULD SAY COVERAGE OF THE STORMS WILL BE THE GREATEST IN THE WEST
AND SOUTHWEST ENDS OF THE AREA. LOT`S OF CLOUDS RIGHT NOW BUT THEY
SHOULD THIN AND ALLOW AT LEAST SOME PARTIAL SUNSHINE.
KCLE GOT TO 90 YESTERDAY AND SEE NO REASON WHY TEMPS WILL BE MUCH
COOLER TODAY AS TEMPS ALOFT REMAIN ABOUT THE SAME. KCAK HAS BEEN
89 OR 90 THE PAST THREE DAYS AS WELL. WILL GO WITH A PERSISTENCE
FORECAST UNTIL FURTHER NOTICE. UPPER 80S LIKELY MOST AREAS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
UPPER RIDGING WILL OCCUR OVER THE AREA THIS WEEKEND BUT IT WILL
TAKE SOME TIME FOR THE DISTURBANCE OVER THE REGION TO DISSIPATE.
EXPECT ONGOING PRECIP THIS EVENING BUT WILL TRY TO DRY THINGS OUT
AFTER MIDNIGHT. EXPECT MORE ISOLATED TO SCATTERED SHOWERS AND
STORMS ON SATURDAY AS A WARM AND HUMID AIRMASS WILL REMAIN
OVERHEAD. BOUNDARIES LEFT OVER FROM THE PREVIOUS DAY AND NIGHTS
STORMS WILL BE THE MAIN TRIGGER FOR WEEKEND CONVECTION. WILL TRY
FOR DRY DAYS SUNDAY AND MONDAY BUT WILL PROBABLY STILL SEE A FEW
POP UPS EACH DAY. THE NEXT FRONTAL SYSTEM WILL BEGIN TO APPROACH
FROM THE NORTHWEST ON MONDAY NIGHT. THE 00Z MODELS HAVE DIFFERENT
OPINIONS ON WHEN THE FRONT WILL ARRIVE WITH THE ECMWF SLOWER THAN
THE GFS. ALREADY HAD CHANCE POPS OVER THE NW HALF OF THE AREA
MONDAY NIGHT AND IT IS PROBABLY PRUDENT TO LEAVE THEM IN EVEN
THOUGH BETTER CHANCES WILL OCCUR IN THE LONG TERM PERIOD.
NOT MUCH CHANGE IN TEMPS IS EXPECTED OVER THE WEEKEND WITH
PERSISTENCE THE WAY TO GO FOR TEMPS.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
ONE MORE DAY OF WELL ABOVE NORMAL TEMPERATURES ON TUESDAY TO START
THE EXTENDED FORECAST WITH TEMPERATURES FALLING TO BELOW NORMAL BY
THE END OF THE WEEK. THE UPPER LEVEL PATTERN WILL FEATURE A BROAD
TROUGH OVER THE MID-SECTION OF THE COUNTRY THAT SLOWLY MOVES EAST
AND FLATTENS THE PERSISTENT UPPER LEVEL RIDGE. A STALLED FRONTAL
BOUNDARY WILL BE LOCATED NEAR OR JUST NORTH OF LAKE ERIE TO START
THE DAY ON TUESDAY. THE GFS REMAINS FASTER THAN THE CANADIAN/ECMWF
WITH WHAT APPEARS TO BE SOME SPURIOUS UPPER LEVEL ENERGY DRIVING THE
FORWARD PROGRESSION OF THE FRONT. THE ATMOSPHERE REMAINS RELATIVELY
DRY OUT AHEAD OF THE FRONT AND OPTED TO KEEP POPS FAIRLY LOW IN THE
EAST ON TUESDAY IN AGREEMENT WITH THE SLOWER MODELS. CHANCES FOR
PRECIPITATION INCREASING DURING THE TUESDAY NIGHT THROUGH WEDNESDAY
NIGHT PERIOD AS THE UPPER TROUGH MOVES THROUGH THE CENTRAL GREAT
LAKES WITH THE EVENTUAL PASSAGE OF A STRONG COLD FRONT EARLY
THURSDAY. SUSPECT THERE WILL BE GOOD COVERAGE OF PRECIPITATION AT
LEAST ONE OF THE PERIODS BUT STILL TOO MUCH UNCERTAINTY IN EVOLUTION
TO GO MORE THAN CHANCE POPS.
TEMPERATURES WILL START OUT IN THE UPPER 80S ON TUESDAY...DROP BACK
TO THE LOWER 80S WITH INCREASING CLOUDS AND THUNDERSTORMS ON
WEDNESDAY AND SETTLE INTO THE LOW TO MID 70S WITH LOWER HUMIDITY TO
END THE WEEK.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
REMNANTS OF OVERNIGHT MCS CONTINUE TO MOVE SE WITH SHOWERS AND
THUNDERSTORMS CONTINUING FROM CLE-CAK AT TAF ISSUANCE. THIS AREA OF
PRECIPITATION WILL TEND TO DECREASE FROM THE NORTH THROUGH 15Z.
ADDITIONAL SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP TODAY
WITH AN UPPER WAVE OVER LOWER MICHIGAN. SEVERAL OF THE HIGH- RES
MODELS ARE SHOWING SCATTERED SHOWERS DEVELOPING BY 15-16Z WITH
DIURNAL HEATING. THUNDERSTORMS WILL INCREASE THROUGH THE AFTERNOON
IN AREAS OF CONVERGENCE AND REMANT OUTFLOW BOUNDARIES...ESPECIALLY
ACROSS NORTHWEST OHIO WHERE INSTABILITY WILL BE GREATEST. ANY
THUNDERSTORM TODAY WILL RESULT IN BRIEF HEAVY RAIN WITH MVFR TO
LOCALLY IFR VISIBILITIES. COVERAGE OF SHOWERS AND THUNDERSTORMS
WILL DECREASE TONIGHT WITH PATCHY GROUND FOG DEVELOPING IF WE
CLEAR OUT. MOST SITES WILL DROP TO MVFR VISIBILITIES LATE TONIGHT.
OUTLOOK...AREAS OF NON VFR EACH MORNING IN FOG AND HAZE. SCATTERED
THUNDERSTORMS MAY DEVELOP AGAIN SATURDAY...BECOMING MORE ISOLATED
BY SUNDAY.
&&
.MARINE...
EASTERLY WINDS TODAY WILL VEER TO SOUTHERLY OVERNIGHT. WITH HIGH
PRESSURE OVER THE EASTERN GREAT LAKES...EXPECT TO SEE LAKE BREEZES
DEVELOP ON SATURDAY AND TO POSSIBLY ON THE EAST END OF THE LAKE ON
SUNDAY. OTHERWISE LIGHT SOUTH TO SOUTHWEST WINDS WILL CONTINUE
DURING THE FIRST HALF OF THE WEEK WITH A STRONG COLD FRONT PUSHING
SOUTH ACROSS THE LAKE EARLY THURSDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KUBINA
NEAR TERM...KUBINA
SHORT TERM...KUBINA
LONG TERM...KEC
AVIATION...KEC
MARINE...KEC
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
635 AM EDT FRI SEP 4 2015
.SYNOPSIS...
AN UPPER AIR DISTURBANCE OVER LOWER MICHIGAN WILL CONTINUE TO
DRIFT SOUTHEAST AND WEAKEN TODAY. A BROAD AREA OF HIGH PRESSURE
AT THE SURFACE AND ALOFT FROM THE MIDWEST TO EASTERN CANADA WILL
REMAIN NEARLY STATIONARY THROUGH LABOR DAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A NICE AREA OF RAIN CONTINUES TO DRIFT ACROSS THE CENTRAL PORTION
OF THE AREA. HEAVY RAIN CURRENTLY FALLING AT KCLE. HAVE BUMPED UP
PRECIP CHANCES A LITTLE FOR THE NEXT FEW HOURS IN THE EAST. WITH
ALL OF THE OUTFLOW BOUNDARIES FLOATING AROUND EXPECT TO CONTINUE
TO SEE NEW STORMS POPPING UP.
A PREVIOUS...SHOWERS AND THUNDERSTORMS CONTINUE TO MOVE AND
REDEVELOP ACROSS NORTH CENTRAL OHIO THIS MORNING. THERE HAS BEEN A
DECREASE IN INTENSITY AND LIGHTNING THE PAST COUPLE OF HOURS BUT
THE LATEST HRRR TAKES THIS AREA OF PRECIP ALL THE WAY TO THE PA
BORDER BY 12Z. WILL KEEP SCATTERED WORDING GOING THROUGH DAYBREAK
OR SO AND THEN BRIEFLY DIMINISH PRECIP CHANCES FOR THE MORNING
HOURS. MORE SHOWERS AND STORMS ARE EXPECTED THIS AFTERNOON. THE
00Z GUIDANCE...ESPECIALLY THE NAM IS SHOWING OVER 4000 J/KG CAPES
THIS AFTERNOON. AND...UNLIKE THE PREVIOUS COUPLE OF DAYS...BETTER
TRIGGERS IN THE FORM OF LEFT OVER BOUNDARIES FROM TONIGHT`S
CONVECTION WILL BE FLOATING AROUND TO KICK OFF NEW STORMS. TOUGH
TO TELL WHEN AND WHERE THE STORMS WILL INITIATE SO WILL KEEP A
GENERIC SCATTERED WORDING MOST OF THE DAY. IF I HAD TO GUESS I
WOULD SAY COVERAGE OF THE STORMS WILL BE THE GREATEST IN THE WEST
AND SOUTHWEST ENDS OF THE AREA. LOT`S OF CLOUDS RIGHT NOW BUT THEY
SHOULD THIN AND ALLOW AT LEAST SOME PARTIAL SUNSHINE.
KCLE GOT TO 90 YESTERDAY AND SEE NO REASON WHY TEMPS WILL BE MUCH
COOLER TODAY AS TEMPS ALOFT REMAIN ABOUT THE SAME. KCAK HAS BEEN
89 OR 90 THE PAST THREE DAYS AS WELL. WILL GO WITH A PERSISTENCE
FORECAST UNTIL FURTHER NOTICE. UPPER 80S LIKELY MOST AREAS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
UPPER RIDGING WILL OCCUR OVER THE AREA THIS WEEKEND BUT IT WILL
TAKE SOME TIME FOR THE DISTURBANCE OVER THE REGION TO DISSIPATE.
EXPECT ONGOING PRECIP THIS EVENING BUT WILL TRY TO DRY THINGS OUT
AFTER MIDNIGHT. EXPECT MORE ISOLATED TO SCATTERED SHOWERS AND
STORMS ON SATURDAY AS A WARM AND HUMID AIRMASS WILL REMAIN
OVERHEAD. BOUNDARIES LEFT OVER FROM THE PREVIOUS DAY AND NIGHTS
STORMS WILL BE THE MAIN TRIGGER FOR WEEKEND CONVECTION. WILL TRY
FOR DRY DAYS SUNDAY AND MONDAY BUT WILL PROBABLY STILL SEE A FEW
POP UPS EACH DAY. THE NEXT FRONTAL SYSTEM WILL BEGIN TO APPROACH
FROM THE NORTHWEST ON MONDAY NIGHT. THE 00Z MODELS HAVE DIFFERENT
OPINIONS ON WHEN THE FRONT WILL ARRIVE WITH THE ECMWF SLOWER THAN
THE GFS. ALREADY HAD CHANCE POPS OVER THE NW HALF OF THE AREA
MONDAY NIGHT AND IT IS PROBABLY PRUDENT TO LEAVE THEM IN EVEN
THOUGH BETTER CHANCES WILL OCCUR IN THE LONG TERM PERIOD.
NOT MUCH CHANGE IN TEMPS IS EXPECTED OVER THE WEEKEND WITH
PERSISTENCE THE WAY TO GO FOR TEMPS.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
ONE MORE DAY OF WELL ABOVE NORMAL TEMPERATURES ON TUESDAY TO START
THE EXTENDED FORECAST WITH TEMPERATURES FALLING TO BELOW NORMAL BY
THE END OF THE WEEK. THE UPPER LEVEL PATTERN WILL FEATURE A BROAD
TROUGH OVER THE MID-SECTION OF THE COUNTRY THAT SLOWLY MOVES EAST
AND FLATTENS THE PERSISTENT UPPER LEVEL RIDGE. A STALLED FRONTAL
BOUNDARY WILL BE LOCATED NEAR OR JUST NORTH OF LAKE ERIE TO START
THE DAY ON TUESDAY. THE GFS REMAINS FASTER THAN THE CANADIAN/ECMWF
WITH WHAT APPEARS TO BE SOME SPURIOUS UPPER LEVEL ENERGY DRIVING THE
FORWARD PROGRESSION OF THE FRONT. THE ATMOSPHERE REMAINS RELATIVELY
DRY OUT AHEAD OF THE FRONT AND OPTED TO KEEP POPS FAIRLY LOW IN THE
EAST ON TUESDAY IN AGREEMENT WITH THE SLOWER MODELS. CHANCES FOR
PRECIPITATION INCREASING DURING THE TUESDAY NIGHT THROUGH WEDNESDAY
NIGHT PERIOD AS THE UPPER TROUGH MOVES THROUGH THE CENTRAL GREAT
LAKES WITH THE EVENTUAL PASSAGE OF A STRONG COLD FRONT EARLY
THURSDAY. SUSPECT THERE WILL BE GOOD COVERAGE OF PRECIPITATION AT
LEAST ONE OF THE PERIODS BUT STILL TOO MUCH UNCERTAINTY IN EVOLUTION
TO GO MORE THAN CHANCE POPS.
TEMPERATURES WILL START OUT IN THE UPPER 80S ON TUESDAY...DROP BACK
TO THE LOWER 80S WITH INCREASING CLOUDS AND THUNDERSTORMS ON
WEDNESDAY AND SETTLE INTO THE LOW TO MID 70S WITH LOWER HUMIDITY TO
END THE WEEK.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
A LARGE AREA OF SHOWERS AND THUNDERSTORMS ACROSS NORTH CENTRAL OHIO
WILL CONTINUE TO MOVE EAST SOUTHEAST OVERNIGHT. EXPECT THE COVERAGE
OF THUNDERSTORMS TO TEND TO DIMINISH WITH TIME...BUT NOT BEFORE
BRINGING ANOTHER ROUND OF THUNDERSTORMS TO CLE/MFD/CAK AND POSSIBLY
THROUGH 09Z WITH LESSER CHANCES AT YNG/ERI IF MCS HOLDS TOGETHER. A
LOW STRATUS DECK HAS BEEN TRYING TO DEVELOP AND EXPECT THIS TO BE
SOMEWHAT VARIABLE OVERNIGHT. VISIBILITIES WILL TEND TO SETTLE INTO
THE MVFR RANGE BUT A FEW SITES WILL LIKELY DIP INTO THE IFR
VISIBILITY RANGE.
SCATTERED THUNDERSTORMS EXPECTED TO DEVELOP AGAIN ON FRIDAY BUT
TIMING WILL AGAIN BE A CHALLENGE. SUFFICIENT INSTABILITY SHOULD BE
IN PLACE FOR SHOWERS AND THUNDERSTORMS TO FIRE ALONG REMNANT OUTFLOW
BOUNDARIES BY MID DAY. TIMING THUNDERSTORMS INTO THE INDIVIDUAL
TERMINALS WILL NEED TO BE REFINED.
OUTLOOK...AREAS OF NON VFR EACH MORNING IN FOG AND HAZE. ISOLATED
THUNDERSTORMS MAY DEVELOP EACH AFTERNOON/EVENING THROUGH SATURDAY.
&&
.MARINE...
EASTERLY WINDS TODAY WILL VEER TO SOUTHERLY OVERNIGHT. WITH HIGH
PRESSURE OVER THE EASTERN GREAT LAKES...EXPECT TO SEE LAKE BREEZES
DEVELOP ON SATURDAY AND TO POSSIBLY ON THE EAST END OF THE LAKE ON
SUNDAY. OTHERWISE LIGHT SOUTH TO SOUTHWEST WINDS WILL CONTINUE
DURING THE FIRST HALF OF THE WEEK WITH A STRONG COLD FRONT PUSHING
SOUTH ACROSS THE LAKE EARLY THURSDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KUBINA
NEAR TERM...KUBINA
SHORT TERM...KUBINA
LONG TERM...KEC
AVIATION...KEC
MARINE...KEC
AREA FORECAST DISCUSSION
NWS MEDFORD OR
858 AM PDT FRI SEP 4 2015
.DISCUSSION...THE UPPER LOW IS NOW CENTERED OVER WESTERN
WASHINGTON AND WILL CONTINUE TO MOVE SOUTH OVER THE AREA LATE
THIS AFTERNOON. A LINE OF SHOWERS AND ISOLATED THUNDERSTORMS BROKE
OUT IN ADVANCE OF AN SHORTWAVE TROUGH ROTATING AROUND THE UPPER
LOW WHICH IS NOW IN NORTHWEST CAL. SHOWERS AND ISOLATED
THUNDERSTORMS WILL INCREASE OVER TIME AS THE UPPER LOW AND COLD
AIR ALOFT (-25C AT 500MB) MOVES OVERHEAD INCREASING INSTABILITY.
THE LATEST HRRR MODEL RUN SHOWS MOST OF THE SHOWERS AND ISOLATED
THUNDERSTORMS ALONG AND EAST OF THE CASCADES, BUT SUSPECT IT MAY
BE UNDERESTIMATING THE CONVECTIVE ACTIVITY WEST OF THE CASCADES.
THEREFORE WE`LL CONTINUE TO KEEP POPS HIGHER WEST OF THE CASCADES
THIS AFTERNOON. IN ADDITION THERE`S A CHANCE SOME THUNDERSTORMS
COULD PRODUCE GUSTY WINDS AND SMALL HAIL.
THE 12Z NAM AND GFS SHOW THE TROUGH AXIS MOVING EAST OF THE
CASCADES LATE TONIGHT AT WHICH POINT THE BULK OF THE PRECIPITATION
WILL SHIFT INTO LAKE, MODOC AND EASTERN KLAMATH COUNTY. SATURDAY
IS STILL A TRANSITION DAY WITH ANY SHOWERS CONFINED TO EASTERN
LAKE COUNTY IN THE MORNING AND DRY CONDITIONS ELSEWHERE.
-PETRUCELLI
&&
.AVIATION...FOR THE 04/12Z TAF CYCLE...VFR CONDITIONS WILL CONTINUE
FOR MOST TAF SITES EARLY THIS MORNING. CLOUDS AND SHOWERS WILL
INCREASE AND CIGS WILL LOWER THROUGH THIS MORNING, ESPECIALLY EAST
OF THE CASCADES WHERE SHOWERS WILL BE MOST NUMEROUS. THUNDERSTORMS
WILL ALSO BE POSSIBLE THIS AFTERNOON. MVFR CIGS AND VIS ARE EXPECTED
IN HEAVIER SHOWERS. ALSO EXPECT MOUNTAIN OBSCURATIONS, ESPECIALLY
OVER AND EAST OF THE CASCADES. THESE CONDITIONS WILL PERSIST INTO
THIS EVENING. -WRIGHT
&&
.MARINE...UPDATED 230 AM PDT FRIDAY 4 SEPTEMBER 2015...NORTH WINDS
WILL CONTINUE THROUGH THE FORECAST PERIOD. A PERIOD OF SMALL CRAFT
ADVISORY LEVEL WINDS IS EXPECTED THIS AFTERNOON AND EVENING SOUTH OF
CAPE BLANCO. WINDS THEN STRENGTHEN AGAIN SUNDAY AS A THERMAL TROUGH
FORMS OVER NORTHERN CALIFORNIA. GALES WILL BE POSSIBLE OVER THE
SOUTHERN WATERS MONDAY AND TUESDAY. SEAS WILL BE PRIMARILY WIND
DRIVEN THROUGH EARLY NEXT WEEK. -WRIGHT
&&
.PREV DISCUSSION... /ISSUED 639 AM PDT FRI SEP 4 2015/
UPDATE...PUT OUT A QUICK UPDATE JUST NOW TO INCREASE POPS ON THE
EAST SIDE AND ALLOW FOR THUNDERSTORMS OVER ALL AREAS THIS MORNING.
AIRMASS IS ALREADY DESTABILIZING QUICKLY AND WE`VE SEEN SIX
LIGHTNING STRIKES ALONG THE SISKIYOU/MODOC BORDER, AND THIS IS
WITH THE MAJORITY OF THE COLD POOL AND INSTABILITY YET TO COME
TODAY. IT ALSO WOULDN`T BE OUT OF THE QUESTION TO SEE A FEW
SNOWFLAKES OVER LAKE AND MODOC COUNTIES THIS MORNING AS SURFACE
TEMPERATURES ARE NEAR OR BELOW FREEZING. TEMP/DEWPOINT SPREAD ARE
FAIRLY HIGH, THOUGH, SO IT MAY BE JUST VIRGA OUT THERE. -WRIGHT
PREV DISCUSSION... /ISSUED 325 AM PDT FRI SEP 4 2015/
DISCUSSION...TEMPERATURES THIS MORNING HAVE BEEN QUITE COLD
RELATIVE TO NORMAL FOR THIS TIME OF YEAR, WITH TEMPERATURES EVEN
DROPPING TO THE MID 20S IN THE GENERAL REGION NEAR CHEMULT. WITH
SEVERAL MORE HOURS OF COOLING TO GO, AND CLOUDS NOT QUITE IN THE
AREA YET, THE CURRENT FROST ADVISORY SEEMS TO BE ON TRACK FOR THE
EAST SIDE. WILL THEREFORE LET THIS RIDE THROUGH THE MORNING.
TEMPERATURES WILL REMAIN MUCH COOLER THAN NORMAL TODAY, AS AMPLE
CLOUDS AND RAIN SHOULD KEEP SOLAR HEATING TO A MINIMUM.
AN UPPER LEVEL LOW, CURRENTLY LOCATED OVER THE SEATTLE AREA, WILL
DROP SOUTH TODAY, AND TAKE POSITION OVER OREGON BY THIS AFTERNOON.
AS IT DROPS SOUTH, A VERY POTENT SHORTWAVE ORBITING THE LOW WILL
PASS OVERHEAD, AND WITH THE LOWERING TEMPERATURES ALOFT, ENOUGH
INSTABILITY AND DYNAMICS SHOULD BE PRESENT TO PRODUCE SHOWERS AND
ISOLATED THUNDERSTORMS OVER THE BULK OF THE FORECAST AREA LATE
THIS MORNING INTO THIS EVENING. WHILE MOST RAINFALL AMOUNTS WILL
BE LIGHT, THERE IS A GOOD CHANCE THAT MANY LOCATIONS COULD SEE
WETTING RAINS. THIS IS PARTICULARLY TRUE EAST OF THE CASCADES,
WHERE FORCING WILL BE STRONGEST DURING THE PEAK OF DAYTIME
HEATING. OVERNIGHT, THE COLD AIR MASS WILL BEGIN TO SETTLE IN.
HOWEVER, THERE SHOULD BE AMPLE CLOUDS REMAINING IN THE AREA, SO
NIGHTTIME LOWS MAY NOT DROP AS LOW AS WOULD BE EXPECTED. HAVE
ADDED PATCHY FROST TO THE FORECAST, BUT GIVEN THE CLOUD COVER, DO
NOT THINK THAT THIS WOULD BE A WIDESPREAD EVENT, SO WILL NOT ISSUE
ANY HEADLINES AT THIS TIME.
THE LOW WILL BEGIN MOVING EAST SATURDAY MORNING, AND GRADUALLY,
SHOWERS AND CLOUDS WILL MOVE OUT OF THE FORECAST AREA AS WELL. EXPECT
THAT THE SKIES WILL BE MOSTLY CLEAR BY SATURDAY NIGHT, AIDED IN PART
TO DEVELOPING OFFSHORE FLOW DRYING OUT THE MID LEVELS. WITH THE COLD
AIR STILL AT THE SURFACE, AND NO CLOUDS TO ACT AS A BLANKET, SUSPECT
THAT THIS WILL BE THE COOLEST NIGHT OF THE WEEK. IN FACT, WIDESPREAD
FROST AND FREEZE IS LIKELY FOR THE EAST SIDE.
THESE COLD TEMPERATURES WILL NOT LAST, HOWEVER, AS UPPER LEVEL
RIDGING WILL BUILD INTO THE AREA, AND THE THERMAL TROUGH WILL RETURN
TO OUR SOUTH. OFFSHORE FLOW SHOULD KEEP THE AREA CLEAR OF CLOUDS,
AND TEMPERATURES WILL RISE TO VALUES AROUND 5 DEGREES ABOVE NORMAL
FOR THIS TIME OF YEAR BY THE MIDDLE OF NEXT WEEK. SEVERAL WAVES WILL
APPROACH THE WEST COAST DURING THIS TIME, BUT THE RIDGE SHOULD KEEP
THE TRACK OF ANY PRECIPITATION MAKING SYSTEMS WELL NORTH OF THE
FORECAST AREA. THEREFORE, FOR THE REMAINDER OF THE FORECAST TERM,
EXPECT GRADUALLY WARMING TEMPERATURES AND DRY CONDITIONS. -BPN
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR PZZ376.
$$
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 PHOENIX AZ
220 PM MST FRI SEP 4 2015
.UPDATE...UPDATED AVIATION AND FIRE WEATHER DISCUSSIONS.
&&
.SYNOPSIS...
SUFFICIENT MOISTURE WILL REMAIN OVER MUCH OF ARIZONA TODAY PROVIDING
GOOD SHOWER AND THUNDERSTORM CHANCES...PARTICULARLY ACROSS THE
EASTERN HALF OF THE STATE. SOMEWHAT DRIER AIR WILL MOVE INTO THE
REGION OVER THE WEEKEND...REDUCING RAINFALL CHANCES VERY SLIGHTLY.
WHILE SOME THUNDERSTORM CHANCES WILL PERSIST DURING THE FIRST HALF
OF NEXT WEEK...A SUBSTANTIALLY WARMER AND DRIER AIRMASS WILL SPREAD
INTO THE AREA FOR THE LATTER HALF OF THE WEEK.
&&
.DISCUSSION... RELATIVELY STRONG UPPER LEVEL TROF REMAINS SITUATED
ALONG THE PAC NORTHWEST COAST EARLY THIS AFTERNOON PUTTING ARIZONA
UNDER SOUTHWEST FLOW ALOFT. IR IMAGERY AT 1 PM SHOWED TS KEVIN OFF
THE SOUTHWEST TIP OF BAJA CA...AND THE SOUTHWEST FLOW WAS TAPPING
INTO THE MID/HIGH LEVEL MOISTURE BEING SHED OFF OF KEVIN. MUCH OF
THIS MOISTURE HAS OVERSPREAD THE EASTERN HALF OF AZ. MORNING
SOUNDINGS SHOWED A MOIST BUT NOT ESPECIALLY UNSTABLE AIRMASS ACROSS
SOUTH CENTRAL AZ WITH PWAT VALUES NEAR 1.5 INCHES BUT RATHER SKINNY
AND MEAGER CAPE. LOW CAPE VALUES WERE DUE TO THE MODEST LAPSE RATES
AND RATHER MOIST ADIABATIC PROFILES AS SEEN IN THE 12Z RAOBS.
STEERING FLOW THIS AFTERNOON AND EVENING WILL BE SOUTHWESTERLY...AND
THE UPPER STREAMLINES DEPICT A LAMINAR AND SLIGHTLY CONFLUENT
FLOW...NOT CONDUCIVE TO STRONG STORM DEVELOPMENT. DYNAMICALLY
SPEAKING...THERE WILL BE WEAK RIPPLES MOVING IN THE SOUTHWESTERLY
FLOW BUT NO STRONG SHORT WAVES APPEAR READY TO MOVE ACROSS ARIZONA
LATER TODAY. HOWEVER THERE IS A JET STREAK RACING ACROSS CENTRAL
AZ...PUTTING THE CENTRAL DESERTS UNDER THE FAVORABLE RIGHT REAR
QUADRANT LATER THIS AFTERNOON.
AT 1 PM SURFACE DEW POINTS OVER THE CENTRAL DESERTS WERE ELEVATED AND
MOSTLY RANGED FROM THE UPPER 50S TO LOW 60S. WITH MOISTURE ELEVATED
AND INSTABILITY LIMITED...AND DYNAMICS BEING A MIXED BAG...IT IS
TOUGH TO SAY JUST HOW THE CONVECTION WILL PLAY OUT TODAY. SOME
MESOSCALE HI RES MODELS SUCH AS THE HRRR AND WRF4KM SUGGEST WE WILL
SEE STORMS IN THE PHOENIX AREA TONIGHT. AS SUCH WE WILL KEEP ABOUT A
30 PERCENT CHANCE FOR SHOWERS AND THUNDERSTORMS ACROSS SOUTH CENTRAL
ARIZONA LATER THIS AFTERNOON AND OVERNIGHT TONIGHT.
FOR THIS WEEKEND...UPPER TROFFING REMAINS SITUATED ALONG THE WEST
COAST AND ARIZONA WILL STAY UNDER A SOUTHWEST FLOW ALOFT.
HOWEVER...LATEST GUIDANCE DOES NOT REALLY DRY OUT THE EASTERN HALF
OF THE STATE...ESPECIALLY IN THE LOWER LEVELS. PWAT VALUES ARE
FORECAST TO REMAIN NEAR OR ABOVE 1.5 INCHES OVER SOUTH CENTRAL
ARIZONA THROUGH SUNDAY...EVEN THOUGH MUCH OF THE MOISTURE FROM KEVIN
WILL HAVE ALREADY LIFTED OUT TO THE NORTHEAST BY SATURDAY EVENING.
AGAIN...DYNAMICS NOT ESPECIALLY IMPRESSIVE EITHER DAY BUT THERE WILL
LIKELY BE WEAK DISTURBANCES MOVING THROUGH THE SOUTHWEST FLOW FROM
TIME TO TIME...INCREASING THE THREAT FOR SHOWERS OR STORMS.
STREAMLINES REMAIN RATHER LAMINAR AND SOUTHWESTERLY...SIMILAR TO
WHAT IS SEEN TODAY. WE FEEL IT IS A BIT OPTIMISTIC TO REMOVE THE
THREAT FOR CONVECTION FROM THE FORECAST THIS WEEKEND...SO WE WILL
RAISE POPS SLIGHTLY AND KEEP SOUTH CENTRAL AZ UNDER AT LEAST A
SLIGHT CHANCE FOR AFTERNOON/EVENING STORMS BOTH SATURDAY AND SUNDAY.
CONVECTIVE POTENTIAL FOR EARLY NEXT WEEK MAY BE SOMEWHAT MORE MUTED
THAN RECENT DAYS AS DEEP LAYER WINDS VEER SOMEWHAT MORE WESTERLY AS
TROUGHING TRANSLATES INTO THE GREAT BASIN AND NRN ROCKIES.
STILL...BOUNDARY LAYER MOISTURE WILL BE DIFFICULT TO COMPLETELY
SCOUR OUT AND SOME MODEST INFUSION OF MIDLEVEL MOISTURE PEELING OFF
THE REMNANTS OF KEVIN MAY BE POSSIBLE. HOWEVER...THERE REMAINS SOME
DISCONNECT WITH THE MORE QUALITY TROPICAL MOISTURE TO THE
SOUTH...AND THE BEST WV TRANSPORT MAY BE DEFLECTED AROUND THE
FORECAST AREA. IN ADDITION...WITH MID LATITUDE TROUGHING LIFTING TO
THE NORTH AND HEIGHTS ALOFT RISING AHEAD OF THE REMNANT TROPICAL
SYSTEM...MODELS DEPICT SUBSTANTIAL MIDLEVEL WARMING AND INCREASED
CONVECTIVE INHIBITION. KEPT SOME MODEST NEAR CLIMATOLOGY POPS
THROUGH TUESDAY...HOWEVER MEASURABLE RAINFALL AT LOWER DESERT
ELEVATIONS MAY BE DIFFICULT TO COME BY.
SOME MINOR UNCERTAINTY STILL EXISTS FOR THE LATTER HALF OF NEXT WEEK
AS SUBTLE DIFFERENCES IN THE SUBTROPICAL RIDGE POSITION WILL DICTATE
IF AND HOW QUICKLY MOISTURE IS COMPLETELY SCOURED SOUTH OF THE
FORECAST AREA. MESOSCALE PROCESSES AND OUTFLOW FROM SONORAN MCS/S
MAY ALLOW FOR GULF SURGES AND BOUNDARY LAYER MOISTURE
ADVECTION...BUT DEFINITIVELY FORECASTING AND TIMING SUCH EVENTS
WOULD PROVE FRUITLESS AT THIS TIME. REGARDLESS...H5 HEIGHT RISES AOA
590DM WILL RESULT IN TEMPERATURES PEAKING BACK ABOVE NORMAL UNDER
GRADUALLY MORE COMPRESSIONAL SUBSIDENT FLOW.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
SCT-BKN MID CLOUDS AOA 10KFT CAN BE EXPECTED THIS THIS EVENING AND
OVERNIGHT...WITH SOME PARTIAL CLEARING OF DEBRIS CLOUDS BY SATURDAY
MORNING. UPPER LEVEL DISTURBANCE WILL KEEP POTENTIAL FOR ISOLATED TO
WIDELY SCATTERED THUNDERSTORMS UNTIL ABOUT 08Z TONIGHT. WITH THE
STORMS COMES THE THREAT FOR GUSTY OUTFLOWS AND LOCAL BLOWING DUST TO
IMPACT TERMINALS ALTHOUGH CONFIDENCE TOO LOW TO INTRODUCE WIND SHIFTS
OR REDUCTIONS IN VISIBILITY IN THE TAFS AT THIS TIME.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
SURFACE WINDS WILL CONTINUE TO FAVOR SOUTH AT KBLH...BECOMING
WESTERLY AT KIPL SOMETIME AFTER 03Z THIS EVENING. SKIES GENERALLY
CLEAR WITH A FEW MID-HIGH CLOUDS DURING PERIOD. ANTICIPATE STORM
ACTIVITY WILL BE ISOLATED AND CONFINED TO AREAS EAST OF THE LOWER
COLORADO RIVER VALLEY.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
STORM CHANCES WILL CONTINUE OVER SOUTH-CENTRAL ARIZONA BEFORE
TRENDING DOWN SIGNIFICANTLY WEDNESDAY. HUMIDITIES WILL ALSO BEGIN TO
TREND DOWN FROM WEST TO EAST ACROSS THE ENTIRE FORECAST AREA NEXT
WEEK...BEGINNING AS EARLY AS MONDAY. A GRADUAL WARMING TREND WILL
ENSUE DURING THE PERIOD CLIMBING TO SEVERAL DEGREES ABOVE NORMAL BY
NEXT THURSDAY.
&&
.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT CONDITIONS ACCORDING TO STANDARD
OPERATING PROCEDURES.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...CB/MO
AVIATION...MEYERS
FIRE WEATHER...MEYERS
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
155 PM MST FRI SEP 4 2015
.SYNOPSIS...
SUFFICIENT MOISTURE WILL REMAIN OVER MUCH OF ARIZONA TODAY PROVIDING
GOOD SHOWER AND THUNDERSTORM CHANCES...PARTICULARLY ACROSS THE
EASTERN HALF OF THE STATE. SOMEWHAT DRIER AIR WILL MOVE INTO THE
REGION OVER THE WEEKEND...REDUCING RAINFALL CHANCES VERY SLIGHTLY.
WHILE SOME THUNDERSTORM CHANCES WILL PERSIST DURING THE FIRST HALF
OF NEXT WEEK...A SUBSTANTIALLY WARMER AND DRIER AIRMASS WILL SPREAD
INTO THE AREA FOR THE LATTER HALF OF THE WEEK.
&&
.DISCUSSION... RELATIVELY STRONG UPPER LEVEL TROF REMAINS SITUATED
ALONG THE PAC NORTHWEST COAST EARLY THIS AFTERNOON PUTTING ARIZONA
UNDER SOUTHWEST FLOW ALOFT. IR IMAGERY AT 1 PM SHOWED TS KEVIN OFF
THE SOUTHWEST TIP OF BAJA CA...AND THE SOUTHWEST FLOW WAS TAPPING
INTO THE MID/HIGH LEVEL MOISTURE BEING SHED OFF OF KEVIN. MUCH OF
THIS MOISTURE HAS OVERSPREAD THE EASTERN HALF OF AZ. MORNING
SOUNDINGS SHOWED A MOIST BUT NOT ESPECIALLY UNSTABLE AIRMASS ACROSS
SOUTH CENTRAL AZ WITH PWAT VALUES NEAR 1.5 INCHES BUT RATHER SKINNY
AND MEAGER CAPE. LOW CAPE VALUES WERE DUE TO THE MODEST LAPSE RATES
AND RATHER MOIST ADIABATIC PROFILES AS SEEN IN THE 12Z RAOBS.
STEERING FLOW THIS AFTERNOON AND EVENING WILL BE SOUTHWESTERLY...AND
THE UPPER STREAMLINES DEPICT A LAMINAR AND SLIGHTLY CONFLUENT
FLOW...NOT CONDUCIVE TO STRONG STORM DEVELOPMENT. DYMAMICALLY
SPEAKING...THERE WILL BE WEAK RIPPLES MOVING IN THE SOUTHWESTERLY
FLOW BUT NO STRONG SHORT WAVES APPEAR READY TO MOVE ACROSS ARIZONA
LATER TODAY. HOWEVER THERE IS A JET STREAK RACING ACROSS CENTRAL
AZ...PUTTING THE CENTRAL DESERTS UNDER THE FAVORABLE RIGHT REAR
QUADRANT LATER THIS AFTERNOON.
AT 1 PM SURFACE DEWPOINTS OVER THE CENTRAL DESERTS WERE ELEVATED AND
MOSTLY RANGED FROM THE UPPER 50S TO LOW 60S. WITH MOISTURE ELEVATED
AND INSTABILITY LIMITED...AND DYNAMICS BEING A MIXED BAG...IT IS
TOUGH TO SAY JUST HOW THE CONVECTION WILL PLAY OUT TODAY. SOME
MESOSCALE HI RES MODELS SUCH AS THE HRRR AND WRF4KM SUGGEST WE WILL
SEE STORMS IN THE PHOENIX AREA TONIGHT. AS SUCH WE WILL KEEP ABOUT A
30 PERCENT CHANCE FOR SHOWERS AND THUNDERSTORMS ACROSS SOUTH CENTRAL
ARIZONA LATER THIS AFTERNOON AND OVERNIGHT TONIGHT.
FOR THIS WEEKEND...UPPER TROFFING REMAINS SITUATED ALONG THE WEST
COAST AND ARIZONA WILL STAY UNDER A SOUTHWEST FLOW ALOFT.
HOWEVER...LATEST GUIDANCE DOES NOT REALLY DRY OUT THE EASTERN HALF
OF THE STATE...ESPECIALLY IN THE LOWER LEVELS. PWAT VALUES ARE
FORECAST TO REMAIN NEAR OR ABOVE 1.5 INCHES OVER SOUTH CENTRAL
ARIZONA THROUGH SUNDAY...EVEN THOUGH MUCH OF THE MOISTURE FROM KEVIN
WILL HAVE ALREADY LIFTED OUT TO THE NORTHEAST BY SATURDAY EVENING.
AGAIN...DYNAMICS NOT ESPECIALLY IMPRESSIVE EITHER DAY BUT THERE WILL
LIKELY BE WEAK DISTURBANCES MOVING THROUGH THE SOUTHWEST FLOW FROM
TIME TO TIME...INCREASING THE THREAT FOR SHOWERS OR STORMS.
STREAMLINES REMAIN RATHER LAMINAR AND SOUTHWESTERLY...SIMILAR TO
WHAT IS SEEN TODAY. WE FEEL IT IS A BIT OPTIMISTIC TO REMOVE THE
THREAT FOR CONVECTION FROM THE FORECAST THIS WEEKEND...SO WE WILL
RAISE POPS SLIGHTLY AND KEEP SOUTH CENTRAL AZ UNDER AT LEAST A
SLIGHT CHANCE FOR AFTERNOON/EVENING STORMS BOTH SATURDAY AND SUNDAY.
CONVECTIVE POTENTIAL FOR EARLY NEXT WEEK MAY BE SOMEWHAT MORE MUTED
THAN RECENT DAYS AS DEEP LAYER WINDS VEER SOMEWHAT MORE WESTERLY AS
TROUGHING TRANSLATES INTO THE GREAT BASIN AND NRN ROCKIES.
STILL...BOUNDARY LAYER MOISTURE WILL BE DIFFICULT TO COMPLETELY
SCOUR OUT AND SOME MODEST INFUSION OF MIDLEVEL MOISTURE PEELING OFF
THE REMNANTS OF KEVIN MAY BE POSSIBLE. HOWEVER...THERE REMAINS SOME
DISCONNECT WITH THE MORE QUALITY TROPICAL MOISTURE TO THE
SOUTH...AND THE BEST WV TRANSPORT MAY BE DEFLECTED AROUND THE
FORECAST AREA. IN ADDITION...WITH MID LATITUDE TROUGHING LIFTING TO
THE NORTH AND HEIGHTS ALOFT RISING AHEAD OF THE REMNANT TROPICAL
SYSTEM...MODELS DEPICT SUBSTANTIAL MIDLEVEL WARMING AND INCREASED
CONVECTIVE INHIBITION. KEPT SOME MODEST NEAR CLIMATOLOGY POPS
THROUGH TUESDAY...HOWEVER MEASURABLE RAINFALL AT LOWER DESERT
ELEVATIONS MAY BE DIFFICULT TO COME BY.
SOME MINOR UNCERTAINTY STILL EXISTS FOR THE LATTER HALF OF NEXT WEEK
AS SUBTLE DIFFERENCES IN THE SUBTROPICAL RIDGE POSITION WILL DICTATE
IF AND HOW QUICKLY MOISTURE IS COMPLETELY SCOURED SOUTH OF THE
FORECAST AREA. MESOSCALE PROCESSES AND OUTFLOW FROM SONORAN MCS/S
MAY ALLOW FOR GULF SURGES AND BOUNDARY LAYER MOISTURE
ADVECTION...BUT DEFINITIVELY FORECASTING AND TIMING SUCH EVENTS
WOULD PROVE FRUITLESS AT THIS TIME. REGARDLESS...H5 HEIGHT RISES AOA
590DM WILL RESULT IN TEMPERATURES PEAKING BACK ABOVE NORMAL UNDER
GRADUALLY MORE COMPRESSIONAL SUBSIDENT FLOW.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
SCT-BKN MID CLOUDS...AOA FL100...CAN BE EXPECTED THIS MORNING WITH
POSSIBLY AN EMBEDDED LIGHT SHOWER. THE SOUTHERN END OF AN UPPER
TROUGH WILL HELP REDEVELOP STORM ACTIVITY OVER ARIZONA AGAIN THIS
AFTERNOON. CONFIDENCE TOO LOW AT THIS POINT TO INSERT TSRA IN
PREVAILING WEATHER OR IN TEMPO GROUPS IN THE TAFS.
OTHERWISE...SURFACE WINDS WILL FAVOR SOUTHEAST AND SOUTH FOR MUCH OF
THE DAY.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
ANTICIPATE FAMILIAR WARM SEASON SURFACE WIND PATTERNS...FAVORING
SOUTHERLY DIRECTIONS. ANY STORM ACTIVITY WILL BE ISOLATED AND
CONFINED TO AREAS EAST OF THE LOWER COLORADO RIVER VALLEY. OTHERWISE
ANTICIPATE ONLY SOME SCATTERED MID TO HIGH LEVEL CLOUDS.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SUNDAY THROUGH THURSDAY...
STORM CHANCES WILL CONTINUE OVER SOUTH-CENTRAL ARIZONA THROUGH
TUESDAY BEFORE TRENDING DOWN SIGNIFICANTLY BEGINNING WEDNESDAY.
HUMIDITIES WILL BEGIN TRENDING DOWN FROM WEST TO EAST NEXT
WEEK...BEGINNING AS EARLY AS MONDAY. A GRADUAL WARMING TREND WILL
CONTINUE NEXT WEEK CLIMBING TO SEVERAL DEGREES ABOVE NORMAL BY NEXT
THURSDAY.
&&
.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT CONDITIONS ACCORDING TO STANDARD
OPERATING PROCEDURES.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...CB/MO
AVIATION...AJ
FIRE WEATHER...AJ
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
345 PM MDT FRI SEP 4 2015
.SHORT TERM...(TONIGHT THROUGH SATURDAY NIGHT)
ISSUED AT 344 PM MDT FRI SEP 4 2015
AN UNSETTLED MOIST SW FLOW CONTINUES THROUGH THESE PERIODS.
THIS AFTERNOON-OVERNIGHT...THE MORNING MODEL RUNS CONTINUE TO NOT
RESOLVE ORGANIZED FORCING. JET SUPPORT REMAINS STRETCHED SW-NE
ACROSS THE FORECAST AREA AND PRECIP WATER VALUES ARE NEAR ONE INCH
IN THE LOWER ELEVATIONS. STORM MOTION IS BRISK...TO THE NE AT
25KTS. THE HRRR SEEMS TO BE CAPTURING THE EARLY AFTERNOON SHOWER
COVERAGE WITH THE NAM AND GFS TOO WET FOR THIS EVENING. THE HRRR
SUGGESTS THE EVENING STORMS WILL BE MAINLY NEAR THE CONTINENTAL
DIVIDE AND PERHAPS THE EASTERN UINTAS. THEN ISOLATED TO SCATTERED
SHOWERS LINGER OVER THE SOUTH INTO SATURDAY MORNING.
IF TODAY IS ANY INDICATION OF HOW TOMORROW WILL BE...THEN SOME SHOWERS
AND THUNDERSTORMS ARE EXPECTED BUT NOTHING TOO IMPRESSIVE. MODELS
HAVE BEEN OVERDOING COVERAGE AND INTENSITY LAST FEW DAYS WITH BOTH
NAM AND GFS PAINTING WIDESPREAD PRECIPITATION WHICH JUST HASN`T
BEEN PANNING OUT. EVEN WITH DECENT UPPER LEVEL SUPPORT...THERE`S
NOT BEEN ANY REAL GOOD SURFACE TRIGGER TO GET STRONG CONVECTION
GOING. FOR SATURDAY...GFS SHOWING ANOTHER DAY OF WIDESPREAD PRECIP
WHILE NAM HAS REALLY PULLED BACK. FORECAST FOLLOWS NAM SO DROPPED
POPS GOOD AMT. THAT`S NOT TO SAY WE WON`T SEE ANY PRECIP...WE
WILL...SOME AFTN/EVENING THUNDERSTORMS ARE EXPECTED WITH SOME
HEAVY RAIN UNDER THE STRONGER CELLS. EXPECT COVERAGE WILL BE
SIMILAR TO TODAY. OF COURSE...HAVING SAID THAT CHANCE HAS NOW
INCREASED FOR TOMORROW TO BE VERY ACTIVE DAY. STAY TUNED. AS FAR
AS TEMPS ARE CONCERNED...PLENTY OF CLOUD COVER WILL KEEP TEMPS
NEAR NORMAL TO A FEW DEGREES BELOW.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 344 PM MDT FRI SEP 4 2015
A FEW DAYS OF NICE WEATHER ON TAP AS LOW PRESSURE SHIFTS NORTH AND
THE ASSOD TROUGH FORCES THE MOISTURE STREAM TO OUR EAST. A FEW
GARDEN VARIETY SHOWERS/STORMS MAY POPUP IN THE AFTERNOON/EVENING
MORE SO FOR MONDAY AND TUESDAY BUT THEY WILL BE VERY FEW AND FAR
BETWEEN FAVORING THE HIGHEST TERRAIN. MOST OF THE CWA WILL SEE
PLENTY OF SUN WITH SOME CU BUILDUP IN THE AFTERNOON WITH SCATTERED
SKIES BEING PREDOMINANT.
THE REMAINDER OF THE LONG TERM WILL SEE PIECES OF ENERGY ROTATING
AROUND THE PERIPHERY OF HIGH PRESSURE TO OUR SOUTH KICKING OFF
SOME SHOWERS/STORMS MAINLY OVER THE SAN JUANS. MEAN FLOW REMAINS
FROM THE WEST TO NORTHWEST KEEPING TEMPS SEASONABLE FOR THIS TIME
OF YEAR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY NOON)
ISSUED AT 1150 AM MDT FRI SEP 4 2015
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS CONTINUES THROUGH
ABOUT 04Z THIS EVENING. ALL TAF SITES WILL BE AFFECTED BY THE
STORMS THOUGH THE SOUTHERN HALF OF THE AREA WILL HAVE THE HIGHER
AREAL COVERAGE. MOUNTAINS WILL BE FREQUENTLY OBSCURED. KTEX AND
KDRO KASE KEGE HAVE ABOUT 60 PERCENT CHANCE OF MVFR CIGS AND VSBYS
IN STRONGER SHOWERS.
AFTER 04Z SHOWERS AND THUNDERSTORMS WILL DECREASE...THEN STORMS
OVER THE SOUTHERN HALF OF THE AREA WILL INCREASE AGAIN AFTER ABOUT
09Z AS ANOTHER DISTURBANCE MOVES IN FROM AZ AND NM.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...JOE/TGR
LONG TERM...TGR
AVIATION...CC/JOE
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
514 PM CDT FRI SEP 4 2015
.SHORT TERM...
235 PM CDT
THROUGH SATURDAY NIGHT...
SHOWERS AND THUNDERSTORMS HAVE BEEN MOST CONCENTRATED...BUT STILL
LARGELY SCATTERED...IN NORTHWEST INDIANA...AND EAST INTO EASTERN
ILLINOIS BUT WELL SOUTH...CLOSER TO A REMNANT FRONTAL BOUNDARY FROM
LAST NIGHT THAT STALLED OUT SOMEWHERE IN THE ROCHELLE TO JOLIET TO
VALPARAISO LINE. MOST OF THIS ACTIVITY HAS CONTINUED EAST. THIS
BOUNDARY STILL REMAINS...BUT WE ALSO NOW HAVE A LAKE BREEZE BOUNDARY
THAT IS NOW MAKING STEADY BUT NOW SLOWING INLAND PROGRESS THIS
AFTERNOON. THIS COMBINED WITH UPPER LEVEL LOW PRESSURE ATOP THE AREA
1500-2500 J/KG OF MIXED LAYER CAPE AWAY FROM THE LAKE IS RESULTING
IN ADDITIONAL ISOLATED DEVELOPMENT THIS AFTERNOON. THE BETTER
INSTABILITY AND CONVERGENCE SLIGHTLY COOLER TEMPS ALOFT STILL RESIDE
FROM THE KANKAKEE RIVER EASTWARD WILL ADDITIONAL DEVELOPMENT WILL
LIKELY CONTINUE. THESE STORMS STILL POSE A HEAVY RAINFALL THREAT IF
THEY CAN CONGEAL AS THEY ARE SLOW MOVING...WITH A LOW CONCERN FOR
GUSTY WINDS IN FORD/IROQUOIS COUNTY ILLINOIS INTO
BENTON/NEWTON/JAPSER COUNTIES OF INDIANA...WITH THE HIGHER
CONCERN EAST INTO CENTRAL INDIANA.
LIKE YESTERDAY...THE LOSS OF DAYTIME HEATING...WE SHOULD SEE
ACTIVITY DIMINISH QUICKLY. THE UPPER LOW LINGERS IN THE REGION
OVERNIGHT. ANOTHER WEAK WAVE WILL ATTEMPT TO MOVE INTO THE UPPER
LEVEL RIDGE THAT WILL BUILD IN FROM THE WEST OVERNIGHT. MANY
GUIDANCE MEMBERS SUGGEST THAT THIS COUPLED WITH SOME RAMPING UP OF
ISENTROPIC LIFT AHEAD OF THIS FEATURE MAY TRIGGER SOME ISOLATED
SHOWERS OR THUNDERSTORMS LATE TONIGHT INTO EARLY SATURDAY. HAVE
MOVED TOWARD THE DRIER NAM SOLUTION AT THIS POINT IN TIME WHICH IS
REFLECTED IN THE EXPERIMENTAL HRRR AND HI-RES NMM/ARW AS WE DO NOT
FEELING FORCING IS STRONG ENOUGH TO TAP INTO ANY ELEVATED
INSTABILITY BUT WILL BE A PERIOD TO WATCH.
THE UPPER RIDGE IS OVER WESTERN ILLINOIS...WITH THE UPPER LOW
INCHING EASTWARD. LOW LEVEL SOUTHWESTERLIES SHOULD ALLOW WARMING ALL
THE WAY TO THE LAKEFRONT WITH 90S INLAND AND UPPER 80S AT THE LAKE.
A WEAKENING OF THE PRESSURE GRADIENT NEAR THE LAKE WOULD SUPPORT A
SE WIND SHIFT NEAR THE LAKE LATER IN THE DAY TO SUPPORT SOME
COOLING. HEAT INDICES WILL GET INTO THE MID TO UPPER 90S IN MANY
SPOTS. HAVE HELD ONTO THE SLIGHT CHANCE POPS FOR TOMORROW
AFTERNOON GIVEN THE MOIST/UNSTABLE ENVIRONMENT...BUT AT THIS POINT
MOST AREAS LOOK TO REMAIN DRY AS THE MAIN TRIGGER IS LACKING.
KMD
&&
.LONG TERM...
SUNDAY THROUGH FRIDAY...
300 PM...MULTIPLE FORECAST CONCERNS INCLUDING HIGH TEMPS SUNDAY
AND MONDAY...PRECIP CHANCES/TIMING LATE SUNDAY NIGHT THRU
WEDNESDAY ALONG WITH HEAVY RAIN POTENTIAL MONDAY NIGHT/TUESDAY.
UPPER RIDGE WILL BE RIGHT OVER THE AREA SUNDAY WITH DRY WEATHER AND
MOSTLY SUNNY SKIES. THIS SHOULD ALLOW TEMPS TO EASILY REACH THE
LOWER 90S INCLUDING ALONG MUCH OF THE IL LAKESHORE AS SOUTHWESTERLY
WINDS APPEAR STRONG ENOUGH THRU MID AFTERNOON TO PREVENT A LAKE
BREEZE. AS THE WINDS DIMINISH IN THE LATER AFTERNOON...WINDS WILL
LIKELY TURN SOUTHEASTERLY ALONG THE IL SHORE COOLING TEMPS A BIT.
WITH DEWPOINTS IN THE UPPER 60S/LOWER 70S...AFTERNOON HEAT INDEX
VALUES COULD CLIMB INTO THE UPPER 90S.
A FRONTAL BOUNDARY WILL MOVE SOUTHEAST ACROSS THE MIDWEST AND
WESTERN LAKES REGION SUNDAY NIGHT REACHING THE AREA MONDAY MORNING.
THE SLOWER TIMING FROM 24 HOURS AGO HAS HELD WITH THE MOST RECENT
GUIDANCE WITH MUCH OF THE AREA STAYING DRY UNTIL EARLY MONDAY
MORNING AND THE BEST CHANCES FOR PRECIP ACROSS NORTHWEST IL TOWARD
DAYBREAK. IT STILL APPEARS THAT PRECIP WILL BE DISSIPATING MONDAY
MORNING BUT TO WHAT EXTENT IS UNCERTAIN. HAVE INTRODUCED MORE OF A
GRADIENT WITH POPS DROPPING OFF TO SLIGHT CHANCE ACROSS THE
SOUTHEAST. POSSIBLE ADDITIONAL DEVELOPMENT MAY OCCUR LATER IN THE
AFTERNOON/EARLY EVENING. PRECIP COVERAGE AND ASSOCIATED CLOUD COVER
MAKE FOR A TRICKY TEMP FORECAST. STILL POSSIBLE TEMPS MAY CLIMB TO
NEAR 90 ACROSS THE SOUTHEAST MONDAY AFTERNOON.
THIS FRONTAL BOUNDARY THEN SLOWS AND STALLS ACROSS THE REGION MONDAY
NIGHT INTO TUESDAY AS AN UPPER WAVE LIFTS NORTHEAST ACROSS THE AREA.
WITH MOISTURE POOLING ALONG THIS BOUNDARY...PERIODS OF HEAVY RAIN
WITH THUNDERSTORMS IS LIKELY SOMEWHERE ACROSS THE REGION...A BIT
EARLY FOR SPECIFICS AND LOCATIONS. AS A STRONGER COLD FRONT MOVES
ACROSS THE AREA TUESDAY INTO TUESDAY NIGHT...THIS SHOULD PUSH THE
PRECIP CHANCES SOUTH OF THE AREA BUT STILL SOME UNCERTAINTY AS TO
HOW FAST THIS OCCURS. ANOTHER WAVE MOVES ACROSS THE AREA LATE NEXT
WEEK AS A LARGE UPPER TROUGH IS PROGGED TO MOVE ACROSS THE LAKES
REGION. GFS/ECMWF HAVE BEEN SHOWING THIS FOR SOME TIME...BUT IT
CONTINUES TO BE DELAYED. IF/WHEN THIS FINALLY ARRIVES...MUCH COOLER
TEMPS AND MUCH LOWER HUMIDITY WITH SPREAD ACROSS THE REGION. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* EAST WINDS JUST SHY OF 10 KT BECMG LGT/VRBL THIS EVE.
MTF/KREIN
//DISCUSSION...UPDATED 18Z...
LATEST WEB CAMS NEAR LAKE MICHIGAN AND DOWNTOWN
CHICAGO...HOWEVER...UGN HAS IMPROVED TO MVFR AND PWK HAS IMPROVED
TO VFR. WITH LITTLE EVIDENCE THAT THE IFR CIGS WILL PENETRATE
INLAND VERY FAR...HAVE REMOVED THE IFR CIGS.
SCT TSRA/SHRA ARE DEVELOPING ALONG AN OLD BOUNDARY EXTENDING FROM
SCNTRL WISCONSIN THROUGH NERN IL AND INTO NWRN INDIANA. EXPECT
THAT SCT TS WILL CONTINUE INTO THE EARLY EVENING...BUT REMAIN SCT
ENOUGH TO MAINTAIN THE VCTS MENTION AS CONFIDENCE IN DIRECT IMPACT
A THE TERMINALS IS LOW. ANTICIPATE THAT CONVECTIVE ACTIVITY SHOULD
WANE WITH SUNSET. A WEAK LAKE BREEZE IS STILL EXPECTED TO DEVELOP
THIS AFTERNOON...WITH LGT/VRBL WINDS BECOMING ELY AT LESS THAN 10
KT. WINDS SHOULD BECM LGT/VRBL OVERNIGHT AGAIN.
SATURDAY SHOULD BE RELATIVELY QUIET THROUGH MUCH OF THE
DAY...THOUGH WITH TROUGHING OVER THE CNTRL PLAINS SHIFTING A
LITTLE EAST...WINDS TOMORROW SHOULD BE PREVAILING SLY AT LESS THAN
10 KT. WITH TEMPS EXPECTED TO REACH NEAR 90F AND DEWPOINTS IN THE
UPPER 60S TO LOWER 70S...THERE SHOULD BE ANOTHER CHANCE FOR SCT
TSRA/SHRA AGAIN TOMORROW AFTERNOON.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* MEDIUM-HIGH IN EASTERLY WINDS REMAINING AROUND 8-9 KT THROUGH
00Z.
* HIGH IN ALL OTHER FORECAST ELEMENTS.
MTF/KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...VFR LIKELY.
SUNDAY...SLIGHT CHANCE OF TSRA LATE.
MONDAY THROUGH WEDNESDAY...CHANCE OF TSRA.
THURSDAY...VFR LIKELY.
LENNING
&&
.MARINE...
315 PM...THE GRADIENT WILL SLOWLY TIGHTEN ACROSS LAKE MICHIGAN
THIS WEEKEND AS A LARGE TROUGH OF LOW PRESSURE OVER THE PLAINS
MOVES EAST WITH HIGH PRESSURE REMAINING OVER THE EASTERN U.S.
SOUTHERLY WINDS WILL LIKELY INCREASE INTO THE 15-25 KT RANGE ON
SUNDAY ESPECIALLY OVER THE NORTHERN PORTION OF THE LAKE. A COLD
FRONT WILL MOVE ACROSS THE LAKE MONDAY AFTERNOON INTO MONDAY
EVENING BUT THIS FRONT WILL SLOW AND STALL ACROSS THE SOUTHERN
LAKES REGION WITH WINDS TURNING BACK SOUTHERLY AHEAD OF ANOTHER
APPROACHING COLD FRONT THAT ARRIVES THURSDAY OR THURSDAY NIGHT
THOUGH CONFIDENCE REGARDING TIMING REMAINS LOW. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
315 PM CDT FRI SEP 4 2015
.SHORT TERM...
235 PM CDT
THROUGH SATURDAY NIGHT...
SHOWERS AND THUNDERSTORMS HAVE BEEN MOST CONCENTRATED...BUT STILL
LARGELY SCATTERED...IN NORTHWEST INDIANA...AND EAST INTO EASTERN
ILLINOIS BUT WELL SOUTH...CLOSER TO A REMNANT FRONTAL BOUNDARY FROM
LAST NIGHT THAT STALLED OUT SOMEWHERE IN THE ROCHELLE TO JOLIET TO
VALPARAISO LINE. MOST OF THIS ACTIVITY HAS CONTINUED EAST. THIS
BOUNDARY STILL REMAINS...BUT WE ALSO NOW HAVE A LAKE BREEZE BOUNDARY
THAT IS NOW MAKING STEADY BUT NOW SLOWING INLAND PROGRESS THIS
AFTERNOON. THIS COMBINED WITH UPPER LEVEL LOW PRESSURE ATOP THE AREA
1500-2500 J/KG OF MIXED LAYER CAPE AWAY FROM THE LAKE IS RESULTING
IN ADDITIONAL ISOLATED DEVELOPMENT THIS AFTERNOON. THE BETTER
INSTABILITY AND CONVERGENCE SLIGHTLY COOLER TEMPS ALOFT STILL RESIDE
FROM THE KANKAKEE RIVER EASTWARD WILL ADDITIONAL DEVELOPMENT WILL
LIKELY CONTINUE. THESE STORMS STILL POSE A HEAVY RAINFALL THREAT IF
THEY CAN CONGEAL AS THEY ARE SLOW MOVING...WITH A LOW CONCERN FOR
GUSTY WINDS IN FORD/IROQUOIS COUNTY ILLINOIS INTO
BENTON/NEWTON/JAPSER COUNTIES OF INDIANA...WITH THE HIGHER
CONCERN EAST INTO CENTRAL INDIANA.
LIKE YESTERDAY...THE LOSS OF DAYTIME HEATING...WE SHOULD SEE
ACTIVITY DIMINISH QUICKLY. THE UPPER LOW LINGERS IN THE REGION
OVERNIGHT. ANOTHER WEAK WAVE WILL ATTEMPT TO MOVE INTO THE UPPER
LEVEL RIDGE THAT WILL BUILD IN FROM THE WEST OVERNIGHT. MANY
GUIDANCE MEMBERS SUGGEST THAT THIS COUPLED WITH SOME RAMPING UP OF
ISENTROPIC LIFT AHEAD OF THIS FEATURE MAY TRIGGER SOME ISOLATED
SHOWERS OR THUNDERSTORMS LATE TONIGHT INTO EARLY SATURDAY. HAVE
MOVED TOWARD THE DRIER NAM SOLUTION AT THIS POINT IN TIME WHICH IS
REFLECTED IN THE EXPERIMENTAL HRRR AND HI-RES NMM/ARW AS WE DO NOT
FEELING FORCING IS STRONG ENOUGH TO TAP INTO ANY ELEVATED
INSTABILITY BUT WILL BE A PERIOD TO WATCH.
THE UPPER RIDGE IS OVER WESTERN ILLINOIS...WITH THE UPPER LOW
INCHING EASTWARD. LOW LEVEL SOUTHWESTERLIES SHOULD ALLOW WARMING ALL
THE WAY TO THE LAKEFRONT WITH 90S INLAND AND UPPER 80S AT THE LAKE.
A WEAKENING OF THE PRESSURE GRADIENT NEAR THE LAKE WOULD SUPPORT A
SE WIND SHIFT NEAR THE LAKE LATER IN THE DAY TO SUPPORT SOME
COOLING. HEAT INDICES WILL GET INTO THE MID TO UPPER 90S IN MANY
SPOTS. HAVE HELD ONTO THE SLIGHT CHANCE POPS FOR TOMORROW
AFTERNOON GIVEN THE MOIST/UNSTABLE ENVIRONMENT...BUT AT THIS POINT
MOST AREAS LOOK TO REMAIN DRY AS THE MAIN TRIGGER IS LACKING.
KMD
&&
.LONG TERM...
SUNDAY THROUGH FRIDAY...
300 PM...MULTIPLE FORECAST CONCERNS INCLUDING HIGH TEMPS SUNDAY
AND MONDAY...PRECIP CHANCES/TIMING LATE SUNDAY NIGHT THRU
WEDNESDAY ALONG WITH HEAVY RAIN POTENTIAL MONDAY NIGHT/TUESDAY.
UPPER RIDGE WILL BE RIGHT OVER THE AREA SUNDAY WITH DRY WEATHER AND
MOSTLY SUNNY SKIES. THIS SHOULD ALLOW TEMPS TO EASILY REACH THE
LOWER 90S INCLUDING ALONG MUCH OF THE IL LAKESHORE AS SOUTHWESTERLY
WINDS APPEAR STRONG ENOUGH THRU MID AFTERNOON TO PREVENT A LAKE
BREEZE. AS THE WINDS DIMINISH IN THE LATER AFTERNOON...WINDS WILL
LIKELY TURN SOUTHEASTERLY ALONG THE IL SHORE COOLING TEMPS A BIT.
WITH DEWPOINTS IN THE UPPER 60S/LOWER 70S...AFTERNOON HEAT INDEX
VALUES COULD CLIMB INTO THE UPPER 90S.
A FRONTAL BOUNDARY WILL MOVE SOUTHEAST ACROSS THE MIDWEST AND
WESTERN LAKES REGION SUNDAY NIGHT REACHING THE AREA MONDAY MORNING.
THE SLOWER TIMING FROM 24 HOURS AGO HAS HELD WITH THE MOST RECENT
GUIDANCE WITH MUCH OF THE AREA STAYING DRY UNTIL EARLY MONDAY
MORNING AND THE BEST CHANCES FOR PRECIP ACROSS NORTHWEST IL TOWARD
DAYBREAK. IT STILL APPEARS THAT PRECIP WILL BE DISSIPATING MONDAY
MORNING BUT TO WHAT EXTENT IS UNCERTAIN. HAVE INTRODUCED MORE OF A
GRADIENT WITH POPS DROPPING OFF TO SLIGHT CHANCE ACROSS THE
SOUTHEAST. POSSIBLE ADDITIONAL DEVELOPMENT MAY OCCUR LATER IN THE
AFTERNOON/EARLY EVENING. PRECIP COVERAGE AND ASSOCIATED CLOUD COVER
MAKE FOR A TRICKY TEMP FORECAST. STILL POSSIBLE TEMPS MAY CLIMB TO
NEAR 90 ACROSS THE SOUTHEAST MONDAY AFTERNOON.
THIS FRONTAL BOUNDARY THEN SLOWS AND STALLS ACROSS THE REGION MONDAY
NIGHT INTO TUESDAY AS AN UPPER WAVE LIFTS NORTHEAST ACROSS THE AREA.
WITH MOISTURE POOLING ALONG THIS BOUNDARY...PERIODS OF HEAVY RAIN
WITH THUNDERSTORMS IS LIKELY SOMEWHERE ACROSS THE REGION...A BIT
EARLY FOR SPECIFICS AND LOCATIONS. AS A STRONGER COLD FRONT MOVES
ACROSS THE AREA TUESDAY INTO TUESDAY NIGHT...THIS SHOULD PUSH THE
PRECIP CHANCES SOUTH OF THE AREA BUT STILL SOME UNCERTAINTY AS TO
HOW FAST THIS OCCURS. ANOTHER WAVE MOVES ACROSS THE AREA LATE NEXT
WEEK AS A LARGE UPPER TROUGH IS PROGGED TO MOVE ACROSS THE LAKES
REGION. GFS/ECMWF HAVE BEEN SHOWING THIS FOR SOME TIME...BUT IT
CONTINUES TO BE DELAYED. IF/WHEN THIS FINALLY ARRIVES...MUCH COOLER
TEMPS AND MUCH LOWER HUMIDITY WITH SPREAD ACROSS THE REGION. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* CHANCE FOR ISOLATED TSRA/SHRA THIS AFTERNOON.
* EAST WINDS LESS THAN 10 KT BECMG LGT/VRBL OVERNIGHT.
KREIN
//DISCUSSION...UPDATED 18Z...
LATEST WEB CAMS NEAR LAKE MICHIGAN AND DOWNTOWN
CHICAGO...HOWEVER...UGN HAS IMPROVED TO MVFR AND PWK HAS IMPROVED
TO VFR. WITH LITTLE EVIDENCE THAT THE IFR CIGS WILL PENETRATE
INLAND VERY FAR...HAVE REMOVED THE IFR CIGS.
SCT TSRA/SHRA ARE DEVELOPING ALONG AN OLD BOUNDARY EXTENDING FROM
SCNTRL WISCONSIN THROUGH NERN IL AND INTO NWRN INDIANA. EXPECT
THAT SCT TS WILL CONTINUE INTO THE EARLY EVENING...BUT REMAIN SCT
ENOUGH TO MAINTAIN THE VCTS MENTION AS CONFIDENCE IN DIRECT IMPACT
A THE TERMINALS IS LOW. ANTICIPATE THAT CONVECTIVE ACTIVITY SHOULD
WANE WITH SUNSET. A WEAK LAKE BREEZE IS STILL EXPECTED TO DEVELOP
THIS AFTERNOON...WITH LGT/VRBL WINDS BECOMING ELY AT LESS THAN 10
KT. WINDS SHOULD BECM LGT/VRBL OVERNIGHT AGAIN.
SATURDAY SHOULD BE RELATIVELY QUIET THROUGH MUCH OF THE
DAY...THOUGH WITH TROUGHING OVER THE CNTRL PLAINS SHIFTING A
LITTLE EAST...WINDS TOMORROW SHOULD BE PREVAILING SLY AT LESS THAN
10 KT. WITH TEMPS EXPECTED TO REACH NEAR 90F AND DEWPOINTS IN THE
UPPER 60S TO LOWER 70S...THERE SHOULD BE ANOTHER CHANCE FOR SCT
TSRA/SHRA AGAIN TOMORROW AFTERNOON.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM CONFIDENCE FOR ISOLD TSRA CHANCES THIS AFTERNOON AND
TOMORROW AFTERNOON...LOW CONFIDENCE IN COVERAGE AND DIRECT
IMPACT ON THE TERMINALS.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...VFR LIKELY.
SUNDAY...SLIGHT CHANCE OF TSRA LATE.
MONDAY THROUGH WEDNESDAY...CHANCE OF TSRA.
THURSDAY...VFR LIKELY.
LENNING
&&
.MARINE...
315 PM...THE GRADIENT WILL SLOWLY TIGHTEN ACROSS LAKE MICHIGAN
THIS WEEKEND AS A LARGE TROUGH OF LOW PRESSURE OVER THE PLAINS
MOVES EAST WITH HIGH PRESSURE REMAINING OVER THE EASTERN U.S.
SOUTHERLY WINDS WILL LIKELY INCREASE INTO THE 15-25 KT RANGE ON
SUNDAY ESPECIALLY OVER THE NORTHERN PORTION OF THE LAKE. A COLD
FRONT WILL MOVE ACROSS THE LAKE MONDAY AFTERNOON INTO MONDAY
EVENING BUT THIS FRONT WILL SLOW AND STALL ACROSS THE SOUTHERN
LAKES REGION WITH WINDS TURNING BACK SOUTHERLY AHEAD OF ANOTHER
APPROACHING COLD FRONT THAT ARRIVES THURSDAY OR THURSDAY NIGHT
THOUGH CONFIDENCE REGARDING TIMING REMAINS LOW. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
300 PM CDT FRI SEP 4 2015
.SHORT TERM...
235 PM CDT
THROUGH SATURDAY NIGHT...
SHOWERS AND THUNDERSTORMS HAVE BEEN MOST CONCENTRATED...BUT STILL
LARGELY SCATTERED...IN NORTHWEST INDIANA...AND EAST INTO EASTERN
ILLINOIS BUT WELL SOUTH...CLOSER TO A REMNANT FRONTAL BOUNDARY FROM
LAST NIGHT THAT STALLED OUT SOMEWHERE IN THE ROCHELLE TO JOLIET TO
VALPARAISO LINE. MOST OF THIS ACTIVITY HAS CONTINUED EAST. THIS
BOUNDARY STILL REMAINS...BUT WE ALSO NOW HAVE A LAKE BREEZE BOUNDARY
THAT IS NOW MAKING STEADY BUT NOW SLOWING INLAND PROGRESS THIS
AFTERNOON. THIS COMBINED WITH UPPER LEVEL LOW PRESSURE ATOP THE AREA
1500-2500 J/KG OF MIXED LAYER CAPE AWAY FROM THE LAKE IS RESULTING
IN ADDITIONAL ISOLATED DEVELOPMENT THIS AFTERNOON. THE BETTER
INSTABILITY AND CONVERGENCE SLIGHTLY COOLER TEMPS ALOFT STILL RESIDE
FROM THE KANKAKEE RIVER EASTWARD WILL ADDITIONAL DEVELOPMENT WILL
LIKELY CONTINUE. THESE STORMS STILL POSE A HEAVY RAINFALL THREAT IF
THEY CAN CONGEAL AS THEY ARE SLOW MOVING...WITH A LOW CONCERN FOR
GUSTY WINDS IN FORD/IROQUOIS COUNTY ILLINOIS INTO
BENTON/NEWTON/JAPSER COUNTIES OF INDIANA...WITH THE HIGHER
CONCERN EAST INTO CENTRAL INDIANA.
LIKE YESTERDAY...THE LOSS OF DAYTIME HEATING...WE SHOULD SEE
ACTIVITY DIMINISH QUICKLY. THE UPPER LOW LINGERS IN THE REGION
OVERNIGHT. ANOTHER WEAK WAVE WILL ATTEMPT TO MOVE INTO THE UPPER
LEVEL RIDGE THAT WILL BUILD IN FROM THE WEST OVERNIGHT. MANY
GUIDANCE MEMBERS SUGGEST THAT THIS COUPLED WITH SOME RAMPING UP OF
ISENTROPIC LIFT AHEAD OF THIS FEATURE MAY TRIGGER SOME ISOLATED
SHOWERS OR THUNDERSTORMS LATE TONIGHT INTO EARLY SATURDAY. HAVE
MOVED TOWARD THE DRIER NAM SOLUTION AT THIS POINT IN TIME WHICH IS
REFLECTED IN THE EXPERIMENTAL HRRR AND HI-RES NMM/ARW AS WE DO NOT
FEELING FORCING IS STRONG ENOUGH TO TAP INTO ANY ELEVATED
INSTABILITY BUT WILL BE A PERIOD TO WATCH.
THE UPPER RIDGE IS OVER WESTERN ILLINOIS...WITH THE UPPER LOW
INCHING EASTWARD. LOW LEVEL SOUTHWESTERLIES SHOULD ALLOW WARMING ALL
THE WAY TO THE LAKEFRONT WITH 90S INLAND AND UPPER 80S AT THE LAKE.
A WEAKENING OF THE PRESSURE GRADIENT NEAR THE LAKE WOULD SUPPORT A
SE WIND SHIFT NEAR THE LAKE LATER IN THE DAY TO SUPPORT SOME
COOLING. HEAT INDICES WILL GET INTO THE MID TO UPPER 90S IN MANY
SPOTS. HAVE HELD ONTO THE SLIGHT CHANCE POPS FOR TOMORROW
AFTERNOON GIVEN THE MOIST/UNSTABLE ENVIRONMENT...BUT AT THIS POINT
MOST AREAS LOOK TO REMAIN DRY AS THE MAIN TRIGGER IS LACKING.
KMD
&&
.LONG TERM...
SUNDAY THROUGH FRIDAY...
300 PM...MULTIPLE FORECAST CONCERNS INCLUDING HIGH TEMPS SUNDAY
AND MONDAY...PRECIP CHANCES/TIMING LATE SUNDAY NIGHT THRU
WEDNESDAY ALONG WITH HEAVY RAIN POTENTIAL MONDAY NIGHT/TUESDAY.
UPPER RIDGE WILL BE RIGHT OVER THE AREA SUNDAY WITH DRY WEATHER AND
MOSTLY SUNNY SKIES. THIS SHOULD ALLOW TEMPS TO EASILY REACH THE
LOWER 90S INCLUDING ALONG MUCH OF THE IL LAKESHORE AS SOUTHWESTERLY
WINDS APPEAR STRONG ENOUGH THRU MID AFTERNOON TO PREVENT A LAKE
BREEZE. AS THE WINDS DIMINISH IN THE LATER AFTERNOON...WINDS WILL
LIKELY TURN SOUTHEASTERLY ALONG THE IL SHORE COOLING TEMPS A BIT.
WITH DEWPOINTS IN THE UPPER 60S/LOWER 70S...AFTERNOON HEAT INDEX
VALUES COULD CLIMB INTO THE UPPER 90S.
A FRONTAL BOUNDARY WILL MOVE SOUTHEAST ACROSS THE MIDWEST AND
WESTERN LAKES REGION SUNDAY NIGHT REACHING THE AREA MONDAY MORNING.
THE SLOWER TIMING FROM 24 HOURS AGO HAS HELD WITH THE MOST RECENT
GUIDANCE WITH MUCH OF THE AREA STAYING DRY UNTIL EARLY MONDAY
MORNING AND THE BEST CHANCES FOR PRECIP ACROSS NORTHWEST IL TOWARD
DAYBREAK. IT STILL APPEARS THAT PRECIP WILL BE DISSIPATING MONDAY
MORNING BUT TO WHAT EXTENT IS UNCERTAIN. HAVE INTRODUCED MORE OF A
GRADIENT WITH POPS DROPPING OFF TO SLIGHT CHANCE ACROSS THE
SOUTHEAST. POSSIBLE ADDITIONAL DEVELOPMENT MAY OCCUR LATER IN THE
AFTERNOON/EARLY EVENING. PRECIP COVERAGE AND ASSOCIATED CLOUD COVER
MAKE FOR A TRICKY TEMP FORECAST. STILL POSSIBLE TEMPS MAY CLIMB TO
NEAR 90 ACROSS THE SOUTHEAST MONDAY AFTERNOON.
THIS FRONTAL BOUNDARY THEN SLOWS AND STALLS ACROSS THE REGION MONDAY
NIGHT INTO TUESDAY AS AN UPPER WAVE LIFTS NORTHEAST ACROSS THE AREA.
WITH MOISTURE POOLING ALONG THIS BOUNDARY...PERIODS OF HEAVY RAIN
WITH THUNDERSTORMS IS LIKELY SOMEWHERE ACROSS THE REGION...A BIT
EARLY FOR SPECIFICS AND LOCATIONS. AS A STRONGER COLD FRONT MOVES
ACROSS THE AREA TUESDAY INTO TUESDAY NIGHT...THIS SHOULD PUSH THE
PRECIP CHANCES SOUTH OF THE AREA BUT STILL SOME UNCERTAINTY AS TO
HOW FAST THIS OCCURS. ANOTHER WAVE MOVES ACROSS THE AREA LATE NEXT
WEEK AS A LARGE UPPER TROUGH IS PROGGED TO MOVE ACROSS THE LAKES
REGION. GFS/ECMWF HAVE BEEN SHOWING THIS FOR SOME TIME...BUT IT
CONTINUES TO BE DELAYED. IF/WHEN THIS FINALLY ARRIVES...MUCH COOLER
TEMPS AND MUCH LOWER HUMIDITY WITH SPREAD ACROSS THE REGION. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* CHANCE FOR ISOLATED TSRA/SHRA THIS AFTERNOON.
* EAST WINDS LESS THAN 10 KT BECMG LGT/VRBL OVERNIGHT.
KREIN
//DISCUSSION...UPDATED 18Z...
LATEST WEB CAMS NEAR LAKE MICHIGAN AND DOWNTOWN
CHICAGO...HOWEVER...UGN HAS IMPROVED TO MVFR AND PWK HAS IMPROVED
TO VFR. WITH LITTLE EVIDENCE THAT THE IFR CIGS WILL PENETRATE
INLAND VERY FAR...HAVE REMOVED THE IFR CIGS.
SCT TSRA/SHRA ARE DEVELOPING ALONG AN OLD BOUNDARY EXTENDING FROM
SCNTRL WISCONSIN THROUGH NERN IL AND INTO NWRN INDIANA. EXPECT
THAT SCT TS WILL CONTINUE INTO THE EARLY EVENING...BUT REMAIN SCT
ENOUGH TO MAINTAIN THE VCTS MENTION AS CONFIDENCE IN DIRECT IMPACT
A THE TERMINALS IS LOW. ANTICIPATE THAT CONVECTIVE ACTIVITY SHOULD
WANE WITH SUNSET. A WEAK LAKE BREEZE IS STILL EXPECTED TO DEVELOP
THIS AFTERNOON...WITH LGT/VRBL WINDS BECOMING ELY AT LESS THAN 10
KT. WINDS SHOULD BECM LGT/VRBL OVERNIGHT AGAIN.
SATURDAY SHOULD BE RELATIVELY QUIET THROUGH MUCH OF THE
DAY...THOUGH WITH TROUGHING OVER THE CNTRL PLAINS SHIFTING A
LITTLE EAST...WINDS TOMORROW SHOULD BE PREVAILING SLY AT LESS THAN
10 KT. WITH TEMPS EXPECTED TO REACH NEAR 90F AND DEWPOINTS IN THE
UPPER 60S TO LOWER 70S...THERE SHOULD BE ANOTHER CHANCE FOR SCT
TSRA/SHRA AGAIN TOMORROW AFTERNOON.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM CONFIDENCE FOR ISOLD TSRA CHANCES THIS AFTERNOON AND
TOMORROW AFTERNOON...LOW CONFIDENCE IN COVERAGE AND DIRECT
IMPACT ON THE TERMINALS.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...VFR LIKELY.
SUNDAY...SLIGHT CHANCE OF TSRA LATE.
MONDAY THROUGH WEDNESDAY...CHANCE OF TSRA.
THURSDAY...VFR LIKELY.
LENNING
&&
.MARINE...
325 AM CDT
QUIET WEATHER AND GENERALLY LIGHT WINDS PERSIST OVER THE LAKE FOR
MOST OF THE HOLIDAY WEEKEND. WAVES COULD GROW A BIT BY LATE SUNDAY
OR MONDAY ACROSS THE NORTH HALF WITH SUSTAINED SOUTHERLY
FLOW...BUT STABLE CONDITIONS WITH COOL WATER AND WARM AIR WILL NOT
SUPPORT SIGNIFICANT WAVE GROWTH. A COLD FRONT CROSSING THE LAKE
FROM WEST TO EAST EARLY NEXT WEEK WILL BRING A CHANGE TO THIS
PATTERN.
LENNING
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
238 PM CDT FRI SEP 4 2015
.SHORT TERM...
235 PM CDT
THROUGH SUNDAY...
SHOWERS AND THUNDERSTORMS HAVE BEEN MOST CONCENTRATED...BUT STILL
LARGELY SCATTERED...IN NORTHWEST INDIANA...AND EAST INTO EASTERN
ILLINOIS BUT WELL SOUTH...CLOSER TO A REMNANT FRONTAL BOUNDARY FROM
LAST NIGHT THAT STALLED OUT SOMEWHERE IN THE ROCHELLE TO JOLIET TO
VALPARAISO LINE. MOST OF THIS ACTIVITY HAS CONTINUED EAST. THIS
BOUNDARY STILL REMAINS...BUT WE ALSO NOW HAVE A LAKE BREEZE BOUNDARY
THAT IS NOW MAKING STEADY BUT NOW SLOWING INLAND PROGRESS THIS
AFTERNOON. THIS COMBINED WITH UPPER LEVEL LOW PRESSURE ATOP THE AREA
1500-2500 J/KG OF MIXED LAYER CAPE AWAY FROM THE LAKE IS RESULTING
IN ADDITIONAL ISOLATED DEVELOPMENT THIS AFTERNOON. THE BETTER
INSTABILITY AND CONVERGENCE SLIGHTLY COOLER TEMPS ALOFT STILL RESIDE
FROM THE KANKAKEE RIVER EASTWARD WILL ADDITIONAL DEVELOPMENT WILL
LIKELY CONTINUE. THESE STORMS STILL POSE A HEAVY RAINFALL THREAT IF
THEY CAN CONGEAL AS THEY ARE SLOW MOVING...WITH A LOW CONCERN FOR
GUSTY WINDS IN FORD/IROQUOIS COUNTY ILLINOIS INTO
BENTON/NEWTON/JAPSER COUNTIES OF INDIANA...WITH THE HIGHER
CONCERN EAST INTO CENTRAL INDIANA.
LIKE YESTERDAY...THE LOSS OF DAYTIME HEATING...WE SHOULD SEE
ACTIVITY DIMINISH QUICKLY. THE UPPER LOW LINGERS IN THE REGION
OVERNIGHT. ANOTHER WEAK WAVE WILL ATTEMPT TO MOVE INTO THE UPPER
LEVEL RIDGE THAT WILL BUILD IN FROM THE WEST OVERNIGHT. MANY
GUIDANCE MEMBERS SUGGEST THAT THIS COUPLED WITH SOME RAMPING UP OF
ISENTROPIC LIFT AHEAD OF THIS FEATURE MAY TRIGGER SOME ISOLATED
SHOWERS OR THUNDERSTORMS LATE TONIGHT INTO EARLY SATURDAY. HAVE
MOVED TOWARD THE DRIER NAM SOLUTION AT THIS POINT IN TIME WHICH IS
REFLECTED IN THE EXPERIMENTAL HRRR AND HI-RES NMM/ARW AS WE DO NOT
FEELING FORCING IS STRONG ENOUGH TO TAP INTO ANY ELEVATED
INSTABILITY BUT WILL BE A PERIOD TO WATCH.
THE UPPER RIDGE IS OVER WESTERN ILLINOIS...WITH THE UPPER LOW
INCHING EASTWARD. LOW LEVEL SOUTHWESTERLIES SHOULD ALLOW WARMING ALL
THE WAY TO THE LAKEFRONT WITH 90S INLAND AND UPPER 80S AT THE LAKE.
A WEAKENING OF THE PRESSURE GRADIENT NEAR THE LAKE WOULD SUPPORT A
SE WIND SHIFT NEAR THE LAKE LATER IN THE DAY TO SUPPORT SOME
COOLING. HEAT INDICES WILL GET INTO THE MID TO UPPER 90S IN MANY
SPOTS. HAVE HELD ONTO THE SLIGHT CHANCE POPS FOR TOMORROW
AFTERNOON GIVEN THE MOIST/UNSTABLE ENVIRONMENT...BUT AT THIS POINT
MOST AREAS LOOK TO REMAIN DRY AS THE MAIN TRIGGER IS LACKING.
KMD
&&
.LONG TERM...
350 AM CDT
SATURDAY THROUGH THURSDAY...
THE BIG STORY OVER THE HOLIDAY WEEKEND WILL BE THE CONTINUED
UNSEASONABLY HOT AND HUMID CONDITIONS. MID/UPPER RIDGING WILL
BECOME EVEN MORE PRONOUNCED AS THE WEAK UPPER LOW COMPLETELY
WASHES OUT. THIS WILL MEAN THAT CONVECTIVE DEVELOPMENT WILL BE
ISOLATED AT BEST ON SATURDAY...AS THERE WILL BE SOME MINOR
CAPPING. WEAK LAKE BREEZE INTO ILLINOIS COULD PROVIDE SOME ADDED
LIFT. OVERALL KEPT POPS IN SLIGHT CHANCE RANGE DURING AFTERNOON
SIMILAR TO PREVIOUS FORECAST. HIGHS IN THE UPPER 80S TO LOWER 90S
AND DEWPOINTS IN THE UPPER 60S TO LOWER 70S WILL SUPPORT HEAT
INDEX VALUES IN THE MID TO UPPER 90S. MINOR EXCEPTION EXPECTED TO
BE IMMEDIATE IL SHORE KEPT SLIGHTLY COOLER BY LAKE BREEZE. SUNDAY
HAS THE POTENTIAL TO BE THE HOTTEST DAY OF THIS STRETCH...WITH
SOLIDLY LOW 90S LIKELY AND MID 90S POSSIBLE IN SPOTS THANKS TO 925
MB TEMPS IN 25-27 CELSIUS RANGE. DEWPOINTS COULD BE A COUPLE
DEGREES LOWER...SO CURRENTLY HEAT INDEX VALUES FORECAST ARE
SIMILAR TO SATURDAY. HAVE MAINTAINED DRY FORECAST FIRMLY UNDER
UPPER RIDGE. MINOR UNCERTAINTY IS WHETHER WINDS WILL TURN
SOUTHEAST ENOUGH ALONG IMMEDIATE IL SHORE TO PROVIDE SOME MINOR
COOLING.
ON SUNDAY NIGHT INTO LABOR DAY...A COLD FRONT WILL BE SLOWLY
APPROACHING FROM THE NORTHWEST AS THE UPPER RIDGE FINALLY GETS
SHOVED EAST BY A FAIRLY DEEP TROUGH ALONG THE CANADIAN BORDER.
SUNDAY EVENING LOOKS TO BE DRY AND THEN HAVE CHANCE POPS MAINLY
WEST OF A PERU TO WAUKEGAN LINE OVERNIGHT. THE BOUNDARY WILL TAKE
ITS SWEET TIME MOVING THROUGH ON LABOR DAY MONDAY INTO TUESDAY AND
THEN A WAVE OF LOW PRESSURE LOOKS TO FORM SOMEWHERE OVER THE MID
MS VALLEY ON TUESDAY AND SHIFT EAST INTO WEDNESDAY. HIGH PRESSURE
OVER THE NORTHERN PLAINS WILL NUDGE THE BAROCLINIC ZONE SOUTH ON
WEDNESDAY...BRINGING COOLER AIR IN AND THEN COOLER AND DRIER AIR
FINALLY ON THURSDAY. HAVE LARGELY STUCK WITH CHANCE POPS FROM
BLENDED GUIDANCE...THOUGH SYNOPTIC SETUP WITH SLOW MOVING FRONT
AND WAVE/S OF LOW PRESSURE ALONG IN AND STRONG MOISTURE TRANSPORT
AHEAD THE BOUNDARY COULD SUPPORT SOME HEFTY RAIN TOTALS IN THE
MONDAY THROUGH WEDNESDAY PERIOD IN PERIODIC SHRA/TSRA. LABOR DAY
ITSELF MAY NOT BE A TOTAL WASHOUT...BUT PLAN FOR A CHANCE FOR
SHOWERS/T-STORMS AND GENERALLY WARM AND MUGGY CONDITIONS FOR
OUTDOOR BBQS. IF YOURE LOOKING FORWARD TO SOME MORE AUTUMN-LIKE
TEMPS...THE WHOLE AREA IS EXPECTED TO BE IN THE 70S ON
THURSDAY...WITH ONLY LOW 70S ALONG THE LAKESHORE.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* CHANCE FOR ISOLATED TSRA/SHRA THIS AFTERNOON.
* EAST WINDS LESS THAN 10 KT BECMG LGT/VRBL OVERNIGHT.
KREIN
//DISCUSSION...UPDATED 18Z...
LATEST WEB CAMS NEAR LAKE MICHIGAN AND DOWNTOWN
CHICAGO...HOWEVER...UGN HAS IMPROVED TO MVFR AND PWK HAS IMPROVED
TO VFR. WITH LITTLE EVIDENCE THAT THE IFR CIGS WILL PENETRATE
INLAND VERY FAR...HAVE REMOVED THE IFR CIGS.
SCT TSRA/SHRA ARE DEVELOPING ALONG AN OLD BOUNDARY EXTENDING FROM
SCNTRL WISCONSIN THROUGH NERN IL AND INTO NWRN INDIANA. EXPECT
THAT SCT TS WILL CONTINUE INTO THE EARLY EVENING...BUT REMAIN SCT
ENOUGH TO MAINTAIN THE VCTS MENTION AS CONFIDENCE IN DIRECT IMPACT
A THE TERMINALS IS LOW. ANTICIPATE THAT CONVECTIVE ACTIVITY SHOULD
WANE WITH SUNSET. A WEAK LAKE BREEZE IS STILL EXPECTED TO DEVELOP
THIS AFTERNOON...WITH LGT/VRBL WINDS BECOMING ELY AT LESS THAN 10
KT. WINDS SHOULD BECM LGT/VRBL OVERNIGHT AGAIN.
SATURDAY SHOULD BE RELATIVELY QUIET THROUGH MUCH OF THE
DAY...THOUGH WITH TROUGHING OVER THE CNTRL PLAINS SHIFTING A
LITTLE EAST...WINDS TOMORROW SHOULD BE PREVAILING SLY AT LESS THAN
10 KT. WITH TEMPS EXPECTED TO REACH NEAR 90F AND DEWPOINTS IN THE
UPPER 60S TO LOWER 70S...THERE SHOULD BE ANOTHER CHANCE FOR SCT
TSRA/SHRA AGAIN TOMORROW AFTERNOON.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM CONFIDENCE FOR ISOLD TSRA CHANCES THIS AFTERNOON AND
TOMORROW AFTERNOON...LOW CONFIDENCE IN COVERAGE AND DIRECT
IMPACT ON THE TERMINALS.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...VFR LIKELY.
SUNDAY...SLIGHT CHANCE OF TSRA LATE.
MONDAY THROUGH WEDNESDAY...CHANCE OF TSRA.
THURSDAY...VFR LIKELY.
LENNING
&&
.MARINE...
325 AM CDT
QUIET WEATHER AND GENERALLY LIGHT WINDS PERSIST OVER THE LAKE FOR
MOST OF THE HOLIDAY WEEKEND. WAVES COULD GROW A BIT BY LATE SUNDAY
OR MONDAY ACROSS THE NORTH HALF WITH SUSTAINED SOUTHERLY
FLOW...BUT STABLE CONDITIONS WITH COOL WATER AND WARM AIR WILL NOT
SUPPORT SIGNIFICANT WAVE GROWTH. A COLD FRONT CROSSING THE LAKE
FROM WEST TO EAST EARLY NEXT WEEK WILL BRING A CHANGE TO THIS
PATTERN.
LENNING
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS MARQUETTE MI
502 PM EDT FRI SEP 4 2015
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 318 PM EDT FRI SEP 4 2015
AN UPPER RIDGE IS STRETCHING FROM A HIGH OVER TX TO WRN UPPER
MI...WRAPPING INTO WRN QUEBEC AROUND A WEAK UPPER DISTURBANCE OVER
LOWER MI. THIS HAS RESULTED IN CLEAR SKIES OVER MOST OF THE
CWA...WHILE SERN SECTIONS HAVE SOME CLOUD COVER. SOME CU IS BREAKING
OUT OVER ERN AND SCENTRAL UPPER MI...AS LOW LEVEL MOISTURE MOVES IS
AHEAD OF THE SLOWLY NORTHWARD MEANDERING DISTURBANCE. UP TO 500J/KG
OF CAPE IS BEING ANALYZED BY THE RAP OVER ERN UPPER MI...WHERE MANY
HIGH-RES MODELS SHOW SOME ISOLATED SHOWERS AND THUNDERSTORMS
BREAKING OUT OVER THE NEXT FEW HOURS. THESE SHOWERS AND
THUNDERSTORMS DIE OFF TONIGHT...BUT WE COULD SEE SOME ADDITIONAL
SHOWERS OVER THAT DIRECTION AS THE DISTURBANCE MOVES OVER. SHOULD
SEE FOG TONIGHT OVER MAINLY CENTRAL AND ERN UPPER MI AS THE LOW
LEVEL MOISTURE CONTINUES TO MOVE IN FROM THE SE.
SAT LOOKS WARMER AS SW FLOW INCREASES AND 850MB TEMPS INCREASE FROM
AROUND 15C TODAY TO 18-21C BY 00Z SUN. EXPECT HIGHS IN THE 70S NEAR
LAKE MICHIGAN...BUT IN THE 80S ELSEWHERE...AND EVEN 90 IN BARAGA. A
WEAK SHORTWAVE MOVING W OF THE AREA LATE TONIGHT INTO SAT MORNING
MAY LEAD TO SOME ISOLATED SHOWERS AND THUNDERSTORMS OVER WRN UPPER
MI. ANOTHER SHORTWAVE MOVES W OF THE AREA SAT
AFTERNOON/EVENING...WHICH MAY LEAD TO SHOWERS AND THUNDERSTORMS OVER
WRN UPPER MI. THE HIGH-RES WRF ARW AND NMM ALONG WITH THE GFS HAVE
THE MOST PRECIP...BUT THE GFS IS VERY MUCH AN OUTLIER AND THE WRFS
ARE MORE REALISTIC. OTHER MODELS ARE DRY FOR THE MOST PART. AS
ALWAYS IN THESE SITUATIONS...CONVECTIVE DEVELOPMENT IS
UNCERTAIN...BUT IT DOES APPEAR THAT ISOLATED TO SCATTERED PRECIP IS
MORE LIKELY. IF AFTERNOON CONVECTION DOES FORM...SOME OF THE STORMS
OVER FAR WRN UPPER MI COULD BE STRONG TO POSSIBLY SEVERE AS MUCAPES
WILL BE 1000-2000J/KG AND 0-6KM BULK SHEAR AROUND 20KTS. THINK
SEVERE CHANCES ARE LOW...BUT IT CAN NOT BE RULED OUT.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 500 PM EDT FRI SEP 4 2015
MODELS SUGGEST THAT WITH A GRADUAL PATTERN PROGRESSION...THE
MID/UPPER LEVEL RIDGE DOMINATING THE CNTRL CONUS WILL TRANSITION TO
A MORE ZONAL PATTERN EARLY NEXT WEEK AND A TROUGH OVER THE CNTRL
CONUS BY THE END OF THE WEEK. SO...ABOVE NORMAL TEMPERATURES WILL
GIVE WAY TO MORE SEASONAL CONDITIONS BY TUESDAY AND BELOW NORMAL
TEMPS BY WED-FRI WITH MORE FALL-LIKE WEATHER.
SAT NIGHT...WITH SW MID/UPPER LEVEL FLOW FROM THE PLAINS TO WRN LAKE
SUPERIOR...THE POTENTIAL WILL REMAIN FOR WEAK SHORTWAVES TO LIFT
INTO THE AREA THAT COULD TRIGGER SCT SHRA/TSRA. LOWER END CHANCE
POPS FOR SHRA/TSRA CHANCES WILL BE CONFINED TO WRN UPPER MI.
SUNDAY THROUGH SUNDAY NIGHT...A VIGOROUS SHORTWAVE TROUGH OVER SW
SASK LIFTING INTO MANITOBA WILL HELP FLATTEN THE RIDGE. A SFC TROUGH
WILL DEVELOP INTO NRN ONTARIO WITH A COLD FRONT THROUGH THE UPPER MS
VALLEY LATE SUNDAY MOVING THROUGH UPPER MI BY LATE SUN NIGHT INTO
EARLY MON. ALTHOUGH SOME SHRA/TSRA MAY BRUSH THE WRN CWA...EXPECT
CAPPING WILL BE STRONG ENOUGH DURING THE PEAK HEATING AND HIGHER
INSTABILITY TO MINIMIZE SHRA/TSRA CHANCES. WITH 850 MB TEMPS NEAR
20C...TEMPS WILL CLIMB WELL ABOVE NORMAL WITH HIGHS IN THE UPPER 80S
TO POSSIBLY 90 IN SSW DOWNSLOPE FLOW LOCATIONS.
AS THE FRONT APPROACHES SUNDAY NIGHT...THE COMBINATION OF HEIGHT
FALLS...LOW LEVEL CONV NEAR THE FRONT AND THE LIKELIHOOD OF WEAKER
SHORTWAVES APPROACHING THE AREA IN SW FLOW FROM THE PLAINS WILL
SUPPORT LIKELY POPS. WITH MUCAPE VALUES TO AT LEAST 1K J/KG AND 0-
6KM SHEAR OF 30-35 KNOTS...SOME STRONGER STORMS WILL BE POSSIBLE.
HOWEVER...WITH HIGH FREEZING LEVELS...PWAT VALUES TO AROUND 2.0
INCHES...AND POTENTIAL FOR BACKBUILDING CONVECTION FROM 45 KT SW
INFLOW...PER CORFIDI VECTORS...HEAVY RAIN MAY BE THE GREATER HAZARD.
MON...SOME SHRA AND POSSIBLY TSRA MAY LINGER INTO EARLY MONDAY OVER
THE ERN CWA...PER SLOWER ECMWF. OTHERWISE...DRIER AIR AND CLEARING
WILL MOVE IN WITH WRLY LOW LEVEL FLOW.
TUE-FRI...PCPN CHANCES ARE MORE UNCERTAIN GIVEN LARGER MODEL
DIFFERENCES WITH THE STRENGTH AND POSITION OF SHORTWAVES AND THE
INTERACTION WITH THE FRONT TO THE SOUTH OF THE REGION. FOR
NOW...ONLY LOWER END SHRA CHANCES WERE INCLUDED...PER MDLS
CONSENSUS. WITH THE MID LEVEL TROUGH DEVELOPING OVER THE
REGION...ENOUGH COLD AIR MAY MOVE IN...PER ECMWF WITH 850 MB
TEMPS DOWN TO 3C...TO SUPPORT LAKE ENHANCED RAIN BY FRI.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 127 PM EDT FRI SEP 4 2015
EXPECT LOWERING CONDITIONS TONIGHT AS LOW LEVEL MOISTURE MOVES
IN...WITH THE LOWEST CONDITIONS AT KSAW WHERE UPSLOPE FLOW WILL BE
OFF LAKE MICHIGAN. CONDITIONS WILL IMPROVE SATURDAY MORNING AS FOG
AND LOW CLOUDS DISSIPATE.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 318 PM EDT FRI SEP 4 2015
EAST TO NORTHEAST WINDS OF 10-15KT WILL CONTINUE UNTIL THE NEXT
CHANCE FOR WINDS GREATER THAN 20KT COMES ON MONDAY BEHIND A COLD
FRONT. FOG WILL CONTINUE TO BE PATCHY ACROSS THE LAKE UNTIL THE COLD
FRONT MOVES THROUGH.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...TITUS
LONG TERM...JLB
AVIATION...TITUS
MARINE...TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
318 PM EDT FRI SEP 4 2015
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 318 PM EDT FRI SEP 4 2015
AN UPPER RIDGE IS STRETCHING FROM A HIGH OVER TX TO WRN UPPER
MI...WRAPPING INTO WRN QUEBEC AROUND A WEAK UPPER DISTURBANCE OVER
LOWER MI. THIS HAS RESULTED IN CLEAR SKIES OVER MOST OF THE
CWA...WHILE SERN SECTIONS HAVE SOME CLOUD COVER. SOME CU IS BREAKING
OUT OVER ERN AND SCENTRAL UPPER MI...AS LOW LEVEL MOISTURE MOVES IS
AHEAD OF THE SLOWLY NORTHWARD MEANDERING DISTURBANCE. UP TO 500J/KG
OF CAPE IS BEING ANALYZED BY THE RAP OVER ERN UPPER MI...WHERE MANY
HIGH-RES MODELS SHOW SOME ISOLATED SHOWERS AND THUNDERSTORMS
BREAKING OUT OVER THE NEXT FEW HOURS. THESE SHOWERS AND
THUNDERSTORMS DIE OFF TONIGHT...BUT WE COULD SEE SOME ADDITIONAL
SHOWERS OVER THAT DIRECTION AS THE DISTURBANCE MOVES OVER. SHOULD
SEE FOG TONIGHT OVER MAINLY CENTRAL AND ERN UPPER MI AS THE LOW
LEVEL MOISTURE CONTINUES TO MOVE IN FROM THE SE.
SAT LOOKS WARMER AS SW FLOW INCREASES AND 850MB TEMPS INCREASE FROM
AROUND 15C TODAY TO 18-21C BY 00Z SUN. EXPECT HIGHS IN THE 70S NEAR
LAKE MICHIGAN...BUT IN THE 80S ELSEWHERE...AND EVEN 90 IN BARAGA. A
WEAK SHORTWAVE MOVING W OF THE AREA LATE TONIGHT INTO SAT MORNING
MAY LEAD TO SOME ISOLATED SHOWERS AND THUNDERSTORMS OVER WRN UPPER
MI. ANOTHER SHORTWAVE MOVES W OF THE AREA SAT
AFTERNOON/EVENING...WHICH MAY LEAD TO SHOWERS AND THUNDERSTORMS OVER
WRN UPPER MI. THE HIGH-RES WRF ARW AND NMM ALONG WITH THE GFS HAVE
THE MOST PRECIP...BUT THE GFS IS VERY MUCH AN OUTLIER AND THE WRFS
ARE MORE REALISTIC. OTHER MODELS ARE DRY FOR THE MOST PART. AS
ALWAYS IN THESE SITUATIONS...CONVECTIVE DEVELOPMENT IS
UNCERTAIN...BUT IT DOES APPEAR THAT ISOLATED TO SCATTERED PRECIP IS
MORE LIKELY. IF AFTERNOON CONVECTION DOES FORM...SOME OF THE STORMS
OVER FAR WRN UPPER MI COULD BE STRONG TO POSSIBLY SEVERE AS MUCAPES
WILL BE 1000-2000J/KG AND 0-6KM BULK SHEAR AROUND 20KTS. THINK
SEVERE CHANCES ARE LOW...BUT IT CAN NOT BE RULED OUT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 452 AM EDT FRI SEP 4 2015
ON SATURDAY...DEEP TROUGH OVER WESTERN CONUS YEILDS BUILDING RIDGE
FM SOUTHERN PLAINS ACROSS REST OF THE EASTERN HALF OF THE CONUS. SFC
FRONT WILL BE ON FRONT EDGE OF TROUGH...RUNNING FM GREAT BASIN INTO
SCNTRL CANADA. SW FLOW ALOFT INTO NORTHERN PLAINS AND UPPER
MISSISSIPPI RIVER VALLEY MAY ALLOW SHORTWAVE WITH SHRA/TSRA TO GRAZE
WESTERN CWA SATURDAY. BEST CHANCES WILL BE OVER WESTERN LK SUPERIOR
CLOSER TO EDGE OF 1000+ J/KG MUCAPE AND WITH WSW STEERING FLOW H85-
H3. DAYTIME HEATING MAY ALSO LEAD TO BUILDUP OF MLCAPES...THOUGH
SOUNDINGS INDICATE MARGINAL MOISTURE TO SUPPORT SHRA/TSRA FM DAYTIME
HEATING ALONE. SLIGHT CHANCES OVER THE WEST WORK ATTM. MAX TEMPS
WELL INTO THE 80S WITH SOUTH WINDS AHEAD OF PLAINS TROUGH AND H85
TEMPS 18-20C. SEVERE POTENTIAL SATURDAY ON LOW SIDE AS EFFECTIVE
SHEAR STAYS MAINLY BLO 30 KTS...THOUGH IT IS SLIGHTLY STRONGER OVER
LK SUPERIOR.
SHORTWAVE WITH SOURCE TO THE NORTH OF TROPICAL STORM KEVIN NEAR BAHA
PENINSULA FORECAST TO TRACK TO NORTHEAST AHEAD OF DEEP TROUGH OVER
WESTERN CONUS. QUITE THE JOURNEY AND PROBABLY WILL BE SOME AFFECTS
FM THE SHORTWAVE AND SMALLER CONVECTIVELY INDUCED SHORTWAVES OVER
THE PLAINS AS MAIN SHORTWAVE INTERACTS WITH 0-3KM MUCAPES 1000-
2000J/KG. SIMILAR TO FRIDAY NIGHT AND SATURDAY...STEERING WINDS
COULD ADVECT SHRA/TSRA DEVELOPING TO THE WEST OF UPPER LAKES OVER
AT LEAST PORTIONS OF CWA. HESITANT TO GET CAUGHT UP IN THE FINER
DETAILS...BUT APPEARS STRONGEST LIFT TRACKS MORE NORTH OF UPR
MICHIGAN ON SUNDAY PER H85-H7 Q-VECTOR CONVERGENCE AND ALSO STAYS
MAINLY SOUTH OF UPR MICHIGAN OVER CNTRL PLAINS CLOSER TO H85 LOW-
LEVEL JET AND THETA-E RIDGE. MLCAPES BUILD UP TO OVER 1000J/KG BUT
HIGHER VALUES ARE MAINLY MN-WI...AND FAR WEST CWA. EFFECTIVE SHEAR
NOT IMPRESSIVE WITH MOST CWA STAYING BLO 25 KTS THROUGH SUN AFTN. A
VERY WARM AND HUMID DAY EXPECTED AS H85 TEMPS SURGE TO 20C BY 18Z-
24Z. UNLESS CLOUDS ARE MORE OF AN ISSUE...INCREASING S-SW WINDS SFC-
H85 AND WARMER TEMPS ALOFT SHOULD RESULT IN TEMPS AROUND 90 DEGREES
MUCH OF THE CWA. COOLER UPR 70S NEAR LK MICHIGAN. GIVEN H85 DWPNTS
13-18C...EXPECT DWPNTS WELL INTO THE 60S AND PROBABLY LOW 70S OVER
AT LEAST WESTERN CWA. THANKFULLY THIS EXTENSIVE HEAT/HUMIDITY WILL
DECREASE INTO MONDAY.
DEEP TROUGH ALOFT MOVES EAST SUNDAY NIGHT WITH SFC LOW DEEPENING
OVER SCNTRL CANADA AND ANOTHER SFC LOW LIFTING OVER NORTHERN
ONTARIO. THE LOW OVER MANITOBA WILL SWING A COLD FRONT ACROSS UPPER
GREAT LAKES SUNDAY NIGHT...AND THIS FRONT SHOULD BE MAINLY EAST OF
CWA AS EARLY AS MONDAY MORNING. MODELS IN DECENT AGREEMENT IN THAT
IDEA. KEPT POPS IN THE LIKELY RANGE AS THE FRONT SWINGS THROUGH
SUNDAY NIGHT. PWATS UP TO 2.0 INCHES ALONG THE FRONT WILL BE NEAR
RECORD VALUES PER SOUNDING PWAT CLIMO FM SPC. STRONG MOISTURE
CONVERGENCE IN VCNTY OF THE FRONT WILL SUPPORT SHRA AND TSRA. IN A
GENERAL SENSE...SEVERE CHANCES DO NOT APPEAR TOO STRONG WITH
ELEVATED CAPES LESS THAN 1000J/KG AHEAD OF FRONT AND 30+ KTS OF DEEP
LAYER SHEAR LAGGING WELL BEHIND SFC-H85 WIND SHIFT. GIVEN THE
ABUNDANCE OF MOISTURE AND FREEZING LEVELS UP TO 14KFT AND CORFIDI
VECTORS UNDER 10 KTS AND SUGGESTING BACKBUILDING POTENTIAL...THINK
HEAVY RAIN IS GOING TO BE THE MAIN HAZARD WITH THE SHRA/TSRA THAT
OCCUR ON SUNDAY NIGHT AND EARLY MONDAY MORNING. CAN NOT RULE OUT
SEVERE POTENTIAL COMPLETELY THOUGH AS 0-1KM SHEAR IS OVER 20 KTS AND
INCREASINGLY PERPENDICULAR TO FRONT MOVING THROUGH. STRONG H85 JET
NOSING IN AHEAD OF FRONT WILL ALSO SUPPORT SOME SEVERE POTENTIAL
WITH PERSISTENT MOISTURE FLUX AND CONVERGENCE. OVERALL THOUGH THINK
THE SEVERE IS A LOWER CHANCE THAN HEAVY RAIN.
FRONT CLEARS KISQ AND KERY BY EARLY MONDAY AFTN. DRY AIR TAKES OVER
FOR THE WEST HALF AS EARLY AS MONDAY MORNING. H85 TEMPS DROP OFF
SOME...BUT SOME AREAS OF CNTRL MAY STILL SNEAK UP TO AROUND 80. 70S
ELSEWHERE WITH DECREASING HUMIDITY...ESPECIALLY WEST.
MINOR CHANCE OF RAIN LATER MONDAY NIGHT INTO TUESDAY...BUT NOW
APPEARS BETTER CHANCES STAY SOUTH OF UPR MICHIGAN ALONG THE FRONT
THAT MOVES THROUGH ON MONDAY. MAIN STORY IN THE TAIL END OF THE
EXTENDED WILL BE COOLER AND DRIER CONDITIONS. LOW TO MID 70S FOR
HIGHS ON TUESDAY. DEEP TROUGHING ALOFT AND CORE OF COOLEST AIR MOVES
ACROSS FOR WEDNESDAY WITH HIGHS IN THE 60S ALL AREAS. LOW 60S NEAR
LK SUPERIOR WITH PARTLY TO MOSTLY CLOUDY SKIES. STAYING COOL ON
THURSDAY WITH MORE 60S EXPECTED. QUITE THE DIFFERENCE FM THE HEAT
AND HUMIDITY IN STORE FOR THIS WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 127 PM EDT FRI SEP 4 2015
EXPECT LOWERING CONDITIONS TONIGHT AS LOW LEVEL MOISTURE MOVES
IN...WITH THE LOWEST CONDITIONS AT KSAW WHERE UPSLOPE FLOW WILL BE
OFF LAKE MICHIGAN. CONDITIONS WILL IMPROVE SATURDAY MORNING AS FOG
AND LOW CLOUDS DISSIPATE.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 318 PM EDT FRI SEP 4 2015
EAST TO NORTHEAST WINDS OF 10-15KT WILL CONTINUE UNTIL THE NEXT
CHANCE FOR WINDS GREATER THAN 20KT COMES ON MONDAY BEHIND A COLD
FRONT. FOG WILL CONTINUE TO BE PATCHY ACROSS THE LAKE UNTIL THE COLD
FRONT MOVES THROUGH.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...TITUS
LONG TERM...JLA
AVIATION...TITUS
MARINE...TITUS
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
328 PM EDT FRI SEP 4 2015
.SYNOPSIS...
A STRONG RIDGE OF HIGH PRESSURE WILL CONTINUE TO PREVAIL
ACROSS THE NORTH COUNTRY THIS WEEKEND. THIS WILL RESULT IN DRY
CONDITIONS WITH WARM DAYS AND COOL NIGHTS. AN ISOLATED SHOWERS IS
POSSIBLE ON SUNDAY AFTERNOON OVER THE ADIRONDACKS MOUNTAINS.
OTHERWISE...THE NEXT CHANCE FOR RAIN WILL BE ASSOCIATED WITH A FRONT
TOWARD THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 310 PM EDT FRIDAY...WATER VAPOR SHOWS BUILDING RIDGE ALOFT
ACROSS THE NE CONUS WITH LARGE SCALE SUBSIDENCE DIRECTLY OVER
REGION. HAVE NOTED A SLIGHT INCREASE IN THICKNESS VALUES AND TEMP
PROFILES COMPARED TO LAST NIGHT...BUT TEMPS WILL BE SIMILAR.
EXPECT A STRONG THERMAL INVERSION TO DEVELOP WITH COOLEST READINGS
IN THE DEEPER/PROTECTED VALLEYS...WITH WARMER TEMPS ON THE
MIDSLOPES AND RIDGETOPS. LOWS WILL RANGE FROM NEAR 40F AT
SLK/COLDER VALLEYS OF THE NEK TO LOWER 60S NEAR THE LAKE CHAMPLAIN
SHORELINE. LATEST RAP CONTS TO SHOW A DEVELOPING 975MB JET OF 15
TO 20 KNOTS ACROSS NORTHERN NY TONIGHT...WHICH MAY KEEP ATMOSPHERE
A LITTLE MIXED AND PREVENT WIDESPREAD DENSE FOG. BEST CHC OF FOG
WILL BE CENTRAL/EASTERN VALLEYS OF VT AFT 06Z.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
AS OF 310 PM EDT FRIDAY...VERY QUIET WEATHER EXPECTED AS
MID/UPPER LVL RIDGE CONTINUES ACROSS THE NE CONUS. THIS WILL
RESULT IN MUCH ABOVE NORMAL TEMPS AND MAINLY DRY CONDITIONS. STILL
WATCHING A WEAK INITIAL 5H VORT AND ASSOCIATED RIBBON OF MOISTURE
THAT IMPACTS OUR WESTERN CWA ON SUNDAY AFTN. SYSTEM HAS LIMITED
FORCING AND IS RUNNING INTO A STRONG RIDGE WITH LOTS OF DRY
AIR...SO WILL KEEP VERY ISOLATED CHANCES FOR AN AFTN SHOWER OVER
NORTHERN NY. THINKING IF ANYTHING DEVELOPS...IT WILL OCCUR OVER
THE TRRN...DURING PEAK HEATING OF THE AFTN HOURS. NAM SOUNDINGS
SHOW CAPE AROUND 1500 J/KG AND UNIDIRECTIONAL WIND PROFILES WITH
SPEEDS BETWEEN 20 AND 25 KNOTS FROM 850 TO 500MB ON SUNDAY
AFTN...AS PWS APPROACH 1.75 INCHES. FORCING AND MOISTURE IS
LIMITED...SO NOT EXPECTING MUCH AREAL COVERAGE OR INTENSITY OF
PRECIP.
OTHERWISE...SFC RIDGE AND BUILDING HEIGHTS ALOFT ON SATURDAY AND
PLENTY OF DRY AIR WILL RESULT IN SUNSHINE AND WARM TEMPS. PROGGED
85H TEMPS BTWN 14 AND 16C SUPPORT HIGHS UPPER 70S MTNS TOWNS TO MID
80S WARMER VALLEYS LOCATIONS LIKE BTV/VSF AND MSS. WINDS WILL
GENERALLY BE TERRAIN DRIVEN...EXCEPT SHIFTING TO THE SOUTH BY
EVENING AS SFC HIGH PRES MOVES INTO THE GULF OF MAINE. A RETURN
SOUTHERLY FLOW WILL ADVECT HIGHER DWPTS BACK INTO OUR REGION BY
SUNDAY...WITH SOME INCREASE IN HUMIDITY VALUES LIKELY. TEMPS SAT
NIGHT WILL RANGE FROM THE MID 40S MTNS VALLEYS TO LOWER/MID 60S CPV
AND URBAN AREAS. ON SUNDAY PROGGED 85H TEMPS ARE NEAR 16C SUPPORTING
HIGHS WELL INTO THE 80S MOST LOCATIONS WITH SOUTH WINDS AT 5 TO 15
MPH.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 327 PM EDT FRIDAY...THE LONG TERM PORTION OF THE FORECAST
WILL START OUT WITH A DRY AND WARM DAY FOR LABOR DAY. GFS MODEL
HINTS AT SOME SCATTERED CONVECTION...WHILE THE ECMWF HAS A DRY DAY
FOR LABOR DAY. THUS...HAVE STUCK WITH THE LOW SUPERBLEND POPS FOR
MONDAY AND MONDAY NIGHT AND HAVE A DRY FORECAST.
ECMWF AND GFS MODELS SHOWING SOME DIFFERENCES ON TUESDAY...WITH
THE GFS MODEL AGAIN HINTING AT SOME SCATTERED CONVECTION ON
TUESDAY...WHILE THE ECMWF MODEL HAS IT DRY AND KEEPS ANY
CONVECTION NORTH OF THE REGION IN CANADA ON TUESDAY AND TUESDAY
NIGHT. HAVE GONE A BIT LOWER THAN SUPERBLEND POPS ON TUESDAY AND
JUST HAVE SLIGHT CHANCE POPS (20 PERCENT) FOR SHOWERS AND
THUNDERSTORMS ON TUESDAY AND TUESDAY NIGHT.
ECMWF AND GFS MODELS IN BETTER AGREEMENT ON WEDNESDAY AND
WEDNESDAY NIGHT WITH BRINGING A SLOW MOVING COLD FRONT INTO THE
REGION. THUS...HAVE STAYED WITH SUPERBLEND POPS FOR WEDNESDAY AND
WEDNESDAY NIGHT AND HAVE A CHANCE OF SHOWERS AND THUNDERSTORMS IN
THE FORECAST FOR WEDNESDAY.
ECMWF AND GFS MODELS SUGGESTING A DRIER FORECAST FOR THURSDAY...SO
HAVE LOWERED SUPERBLEND POPS TO JUST SLIGHT CHANCE POPS (20
PERCENT) FOR SHOWERS ON THURSDAY. ECMWF AND GFS MODELS SHOWING
MOISTURE RETURNING INTO THE REGION ON FRIDAY...SO HAVE A CHANCE OF
SHOWERS IN THE FORECAST FOR FRIDAY.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
THROUGH 18Z SATURDAY...MAINLY VFR CONDITIONS EXPECTED THROUGH THE
PERIOD AS A RIDGE OF HIGH PRESSURE AT THE SURFACE AND ALOFT WILL
BE OVER VERMONT AND NORTHERN NEW YORK. SATELLITE LOOP JUST SHOWING
MAINLY CLEAR SKIES OR JUST A FEW HIGH THIN CIRRUS CLOUDS ACROSS
THE REGION AT THIS TIME. EXPECTING SOME AREAS OF DENSE FOG TO
FORM IN THE SHELTERED VALLEYS OF NORTH CENTRAL AND EASTERN AND
NORTHEAST VERMONT MAINLY FROM 05Z SATURDAY UNTIL 14Z SATURDAY.
ALSO EXPECTING SOME AREAS OF DENSE FOG IN THE SHELTERED VALLEYS OF
THE ADIRONDACKS AFTER 06Z SATURDAY UNTIL 12Z SATURDAY.
OUTLOOK 18Z SATURDAY THROUGH WEDNESDAY...
18Z SAT-00Z TUE...MAINLY VFR EXCEPT FOR VLIFR/IFR FG/BR LIKELY AT
KSLK/KMPV 06Z-13Z EACH MORNING.
00Z TUE-00Z THU...MAINLY VFR. CHANCE SHRA/TSRA WITH FRONTAL
PASSAGE.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...TABER
NEAR TERM...TABER
SHORT TERM...TABER
LONG TERM...WGH
AVIATION...WGH
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
309 PM EDT FRI SEP 4 2015
.SYNOPSIS...
A STRONG RIDGE OF HIGH PRESSURE WILL CONTINUE TO PREVAIL
ACROSS THE NORTH COUNTRY THIS WEEKEND. THIS WILL RESULT IN DRY
CONDITIONS WITH WARM DAYS AND COOL NIGHTS. AN ISOLATED SHOWERS IS
POSSIBLE ON SUNDAY AFTERNOON OVER THE ADIRONDACKS MOUNTAINS.
OTHERWISE...THE NEXT CHANCE FOR RAIN WILL BE ASSOCIATED WITH A FRONT
TOWARD THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 310 PM EDT FRIDAY...WATER VAPOR SHOWS BUILDING RIDGE ALOFT
ACROSS THE NE CONUS WITH LARGE SCALE SUBSIDENCE DIRECTLY OVER
REGION. HAVE NOTED A SLIGHT INCREASE IN THICKNESS VALUES AND TEMP
PROFILES COMPARED TO LAST NIGHT...BUT TEMPS WILL BE SIMILAR.
EXPECT A STRONG THERMAL INVERSION TO DEVELOP WITH COOLEST READINGS
IN THE DEEPER/PROTECTED VALLEYS...WITH WARMER TEMPS ON THE
MIDSLOPES AND RIDGETOPS. LOWS WILL RANGE FROM NEAR 40F AT
SLK/COLDER VALLEYS OF THE NEK TO LOWER 60S NEAR THE LAKE CHAMPLAIN
SHORELINE. LATEST RAP CONTS TO SHOW A DEVELOPING 975MB JET OF 15
TO 20 KNOTS ACROSS NORTHERN NY TONIGHT...WHICH MAY KEEP ATMOSPHERE
A LITTLE MIXED AND PREVENT WIDESPREAD DENSE FOG. BEST CHC OF FOG
WILL BE CENTRAL/EASTERN VALLEYS OF VT AFT 06Z.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
AS OF 310 PM EDT FRIDAY...VERY QUIET WEATHER EXPECTED AS
MID/UPPER LVL RIDGE CONTINUES ACROSS THE NE CONUS. THIS WILL
RESULT IN MUCH ABOVE NORMAL TEMPS AND MAINLY DRY CONDITIONS. STILL
WATCHING A WEAK INITIAL 5H VORT AND ASSOCIATED RIBBON OF MOISTURE
THAT IMPACTS OUR WESTERN CWA ON SUNDAY AFTN. SYSTEM HAS LIMITED
FORCING AND IS RUNNING INTO A STRONG RIDGE WITH LOTS OF DRY
AIR...SO WILL KEEP VERY ISOLATED CHANCES FOR AN AFTN SHOWER OVER
NORTHERN NY. THINKING IF ANYTHING DEVELOPS...IT WILL OCCUR OVER
THE TRRN...DURING PEAK HEATING OF THE AFTN HOURS. NAM SOUNDINGS
SHOW CAPE AROUND 1500 J/KG AND UNIDIRECTIONAL WIND PROFILES WITH
SPEEDS BETWEEN 20 AND 25 KNOTS FROM 850 TO 500MB ON SUNDAY
AFTN...AS PWS APPROACH 1.75 INCHES. FORCING AND MOISTURE IS
LIMITED...SO NOT EXPECTING MUCH AREAL COVERAGE OR INTENSITY OF
PRECIP.
OTHERWISE...SFC RIDGE AND BUILDING HEIGHTS ALOFT ON SATURDAY AND
PLENTY OF DRY AIR WILL RESULT IN SUNSHINE AND WARM TEMPS. PROGGED
85H TEMPS BTWN 14 AND 16C SUPPORT HIGHS UPPER 70S MTNS TOWNS TO MID
80S WARMER VALLEYS LOCATIONS LIKE BTV/VSF AND MSS. WINDS WILL
GENERALLY BE TERRAIN DRIVEN...EXCEPT SHIFTING TO THE SOUTH BY
EVENING AS SFC HIGH PRES MOVES INTO THE GULF OF MAINE. A RETURN
SOUTHERLY FLOW WILL ADVECT HIGHER DWPTS BACK INTO OUR REGION BY
SUNDAY...WITH SOME INCREASE IN HUMIDITY VALUES LIKELY. TEMPS SAT
NIGHT WILL RANGE FROM THE MID 40S MTNS VALLEYS TO LOWER/MID 60S CPV
AND URBAN AREAS. ON SUNDAY PROGGED 85H TEMPS ARE NEAR 16C SUPPORTING
HIGHS WELL INTO THE 80S MOST LOCATIONS WITH SOUTH WINDS AT 5 TO 15
MPH.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 255 AM EDT FRIDAY...AS WE FINISH UP THE LONG HOLIDAY
WEEKEND THE AFOREMENTIONED UPPER RIDGE CONTINUES TO BREAK DOWN TO
ZONAL FLOW ACROSS THE NORTHEAST WHILE SURFACE HIGH PRESSURE
REMAINS OVER THE EASTERN SEABOARD. THE RESULTING WEATHER WILL BE
CONTINUED WARM ADD DRY CONDITIONS SUNDAY NIGHT THROUGH MONDAY
NIGHT WITH TEMPERATURES WELL ABOVE NORMAL RUNNING IN THE UPPER 50S
TO MID 60S FOR LOWS, AND MID TO UPPER 80S FOR HIGHS.
FOR TUESDAY, LONG RANGE GUIDANCE STILL SHOWING SOME DIFFERENCES IN
THE DEPTH OF MOISTURE AND STRENGTH OF A PRE-FRONTAL TROUGH PUSHING
THROUGH THE REGION. GFS AND CANADIAN GEM CONTINUE TO HIGHLIGHT A
LITTLE BETTER MOISTURE THAN THE ECMWF WHICH HOLDS ON STRONGER TO THE
RIDGE IN PLACE. IN ALL LIKELIHOOD A SOLUTION SOMEWHERE IN THE MIDDLE
WILL OCCUR WITH A FEW LIGHT SCATTERED SHOWERS, BUT NOT EXPECTING
MUCH OVERALL IMPACT. MEANWHILE, MODELS ARE IN GOOD AGREEMENT MOVING
FORWARD TO THE WEDNESDAY/THURSDAY TIME-FRAME WHERE A MORE POTENT
UPPER TROUGH AND SURFACE COLD FRONT TRACK FROM THE GREAT LAKES
THROUGH THE NORTHEAST. AS THE PREVIOUS FORECASTER MENTIONED THOUGH,
THE BEST DYNAMICS LIFT NORTHEASTWARD WITH THE PARENT SURFACE LOW
WEDNESDAY, BUT THE TRAILING SHORTWAVE TROUGH SHIFTS RIGHT THROUGH
THE BTV CWA THURSDAY LIKELY PRODUCING MORE WIDESPREAD CONVECTIVE
SHOWERS. ONE THING`S FOR SURE, BEHIND THIS FRONT WE WILL SEE A
RETURN TO MORE NORMAL LATE SUMMER TEMPERATURES AND HOPEFULLY
(FINGERS CROSSED) THE END OF THIS HOT/HUMID STRETCH.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
THROUGH 18Z SATURDAY...MAINLY VFR CONDITIONS EXPECTED THROUGH THE
PERIOD AS A RIDGE OF HIGH PRESSURE AT THE SURFACE AND ALOFT WILL
BE OVER VERMONT AND NORTHERN NEW YORK. SATELLITE LOOP JUST SHOWING
MAINLY CLEAR SKIES OR JUST A FEW HIGH THIN CIRRUS CLOUDS ACROSS
THE REGION AT THIS TIME. EXPECTING SOME AREAS OF DENSE FOG TO
FORM IN THE SHELTERED VALLEYS OF NORTH CENTRAL AND EASTERN AND
NORTHEAST VERMONT MAINLY FROM 05Z SATURDAY UNTIL 14Z SATURDAY.
ALSO EXPECTING SOME AREAS OF DENSE FOG IN THE SHELTERED VALLEYS OF
THE ADIRONDACKS AFTER 06Z SATURDAY UNTIL 12Z SATURDAY.
OUTLOOK 18Z SATURDAY THROUGH WEDNESDAY...
18Z SAT-00Z TUE...MAINLY VFR EXCEPT FOR VLIFR/IFR FG/BR LIKELY AT
KSLK/KMPV 06Z-13Z EACH MORNING.
00Z TUE-00Z THU...MAINLY VFR. CHANCE SHRA/TSRA WITH FRONTAL
PASSAGE.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...TABER
NEAR TERM...TABER
SHORT TERM...TABER
LONG TERM...LAHIFF
AVIATION...WGH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1207 PM CDT FRI SEP 4 2015
.UPDATE...
ISSUED AT 1202 PM CDT FRI SEP 4 2015
AS OF 17 UTC...THE STRONGEST CONVECTION WAS FOCUSING ACROSS THE
DEVILS LAKE BASIN AND INTO THE NORTHERN RED RIVER VALLEY AHEAD OF
THE SHORTWAVE OVER THE SOUTHERN JAMES RIVER VALLEY. AS THIS WAVE
CONTINUES TO PROPAGATE NORTHEAST...EXPECT A DOWNWARD TREND IN
PRECIPITATION COVERAGE THROUGH THE AFTERNOON.
UPDATE ISSUED AT 902 AM CDT FRI SEP 4 2015
UPDATE TO BLEND OBSERVED RADAR TRENDS TO A TIME LAGGED ENSEMBLE OF
THE 10-12 UTC HRRR ITERATIONS WHICH HAVE A GOOD HANDLE OF ONGOING
CONVECTION THIS MORNING. SPC HAS MAINTAINED THE MARGINAL RISK FOR
SEVERE STORMS FOR THE TURTLE MOUNTAINS THROUGH THE JAMES RIVER
VALLEY AND POINTS EAST THIS AFTERNOON. THE 13 UTC RAP FORECAST
DEPICTS 1500-2000 J/KG OF ML CAPE AND 20-25 KTS OF DEEP LAYER
SHEAR THIS AFTERNOON ACROSS THE AFOREMENTIONED AREAS...SUPPORTING
THE MARGINAL RISK FOR POSSIBLY A SEVERE STORM OR TWO.
HOWEVER...THE RAP ALSO PROPAGATES THE MAIN FORCING MECHANISM OF
THE SHORTWAVE ACROSS CENTRAL SOUTH DAKOTA THIS MORNING INTO
NORTHEAST NORTH DAKOTA LATE THIS AFTERNOON. THUS...THE TIMING OF
THE WAVE SUGGESTS THE BEST POTENTIAL FOR STRONG TO SEVERE STORMS MAY
RESIDE NORTHEAST OF THE CWA.
UPDATE ISSUED AT 628 AM CDT FRI SEP 4 2015
SHOWERS CONTINUE TO LIFT SOUTH TO NORTH OVER THE AREA THIS
MORNING...WITH THE GREATEST COVERAGE AT THIS TIME OVER FAR
WESTERN NORTH DAKOTA. ANOTHER AREA CONTINUES TO DEVELOP OVER
PORTIONS OF SOUTH CENTRAL NORTH DAKOTA...WHILE A BROAD AREA OVER
CENTRAL SOUTH DAKOTA CONTINUES TO LIFT TOWARDS OUR REGION. FOR THE
MORNING UPDATE...HAVE TRIED TO TIME OUT THE MOTION/ARRIVAL OF
THESE STORMS BASED ON CURRENT TRENDS AND LATEST HRRR GUIDANCE AND
HAVE ADJUSTED POPS ACCORDINGLY. UPDATES HAVE BEEN SENT.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 423 AM CDT FRI SEP 4 2015
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE CHANCES FOR
SHOWERS AND THUNDERSTORMS THROUGH THE PERIOD. HEAVY RAIN POTENTIAL
FAR NORTHWEST THIS MORNING AND POSSIBLY ACROSS THE JAMES RIVER
VALLEY.
CURRENTLY...SOUTH-SOUTHWEST FLOW ALOFT. STRONG EMBEDDED S/WV
IMPULSE LIFTING ACROSS WESTERN SOUTH DAKOTA TOWARDS CENTRAL NORTH
DAKOTA RESULTING IN AN INCREASE IN COVERAGE AND INTENSITY IN
SHOWERS AND THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS THE
PAST FEW HOURS. THE MOST FAVORED AREAS WILL BE ALONG A QUASI-
STATIONARY FRONTAL BOUNDARY DRAPED FROM SOUTHWESTERN NORTH DAKOTA
NORTHEAST THROUGH THE TURTLE MOUNTAINS...AND ACROSS MY NORTHWEST
NEAR A POST FRONTAL AXIS. ANOMALOUS MOISTURE SURGING INTO THE
NORTHERN PLAINS WITH LATEST WATER VAPOR LOOP INDICATING A WELL
DEFINED MID/UPPER LEVEL MOISTURE FEED FROM TROPICAL STORM FRED
SOUTHWEST OF BAJA CALIFORNIA. WARM MID-ATMOSPHERIC PROFILE
SUGGESTS A MORE LOCALIZED HEAVY RAIN THREAT VERSUS WIDESPREAD.
WILL CONTINUE TO MONITOR.
AS MENTIONED ABOVE...AND AS HIGH RES AND LATEST NAM MODEL
SUGGEST...NORTHWESTERN NORTH DAKOTA AND THE JAMES RIVER VALLEY
LOOK HAVE THE GREATEST POTENTIAL AT THIS TIME FOR HEAVY RAINFALL.
VIGOROUS CONVECTION OVER SOUTHEASTERN SASKATCHEWAN SHOWING SOME
SIGNS OF DEVELOPING SOUTH INTO MY NORTHWEST. CONVECTIVE COMPLEX
OVER CENTRAL SOUTH DAKOTA MOVING NORTH WHICH LATEST NAM AND HRRR
BRING INTO THE JAMES RIVER BASIN 12-15Z OR SO. VERY UNSEASONABLE
HIGH DEWPOINT TEMPERATURES OUT THERE IN THE 60S TO LOW 70S
CENTRAL AND EAST.
EMBEDDED WAVE CONTINUES TO LIFT NORTH-NORTHEAST TODAY AND EXPECT
CLEARING SKIES AND DECREASING CHANCES FOR SHOWERS/THUNDERSTORMS
FROM SOUTH TO NORTH IN THE WAVE`S WAKE THIS AFTERNOON. LATEST SPC
OUTLOOK MOVED THE SLIGHT RISK AREA INTO MAINLY THE RED RIVER
VALLEY OF EASTERN NORTH DAKOTA...SO OPTED TO REMOVE SEVERE WORDING
IN OUR PRODUCTS. MODELS HINTING AT LOW LEVEL STRATUS/FOG DEVELOPING
TONIGHT WITH LOW LEVEL MOISTURE REMAINING HIGH COUPLED WITH
FORECAST RAINFALL TODAY.
NEXT STRONG EMBEDDED WAVE LIFTS NORTH-NORTHEAST LATE TONIGHT INTO
SATURDAY...WITH INCREASING POPS WEST LATE TONIGHT THEN SPREADING
EAST AND NORTH ACROSS THE REMAINDER OF THE STATE DURING THE DAY
SATURDAY.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 359 AM CDT FRI SEP 4 2015
UPPER LEVEL TROUGH CLOSES OFF TOWARDS NORTHERN MONTANA THROUGH THE
NIGHT ON SATURDAY WITH PRECIPITATION CHANCES SLOWLY TAPERING OFF
THROUGH THE NIGHT FROM SOUTH TO NORTH. ON SUNDAY...GREATEST
CHANCES WILL BE RESTRICTED TO NORTHERN PORTIONS OF THE AREA AS
UPPER LOW STARTS TO WORK ITS WAY TOWARDS THE EAST/NORTHEAST ACROSS
THE SOUTHERN PRAIRIE PROVINCES. DRY CONDITIONS EXPECTED OVER MOST
LOCATIONS BY SUNDAY NIGHT. BREEZY/WINDY CONDITIONS EXPECTED ON
SUNDAY AS SYSTEM BECOMES STACKED.
MAINLY DRY CONDITIONS EXPECTED ON MONDAY WITH COOLING TREND
CONTINUING AS LOW CONTINUES ITS TRACK NORTH OF THE AREA. THIS WILL
BRING CONTINUED BREEZY CONDITIONS OVER NORTHERN LOCATIONS. MAINLY
DRY CONDITIONS EXPECTED THROUGH MID-WEEK WITH A GRADUAL WARMING
TREND EXPECTED AS RIDGE BUILDS OVER WESTERN CONUS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1202 PM CDT FRI SEP 4 2015
WIDESPREAD MVFR/IFR STRATUS ACROSS WESTERN AND CENTRAL NORTH
DAKOTA WILL SLOWLY LIFT AND ERRODE INTO THE AFTERNOON.
THUNDERSTORMS ARE EXPECTED TO IMPACT KJMS THROUGH 19-20 UTC. FOG
AND STRATUS MAY BUILD ACROSS MUCH OF THE AREA AGAIN TONIGHT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...NH
LONG TERM...JJS
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS MEDFORD OR
1258 PM PDT FRI SEP 4 2015
.DISCUSSION...THE UPPER LOW IS NOW CENTERED OVER WESTERN WASHINGTON
AND WILL CONTINUE TO MOVE SOUTH OVER THE AREA LATE THIS AFTERNOON.
SHOWERS AND ISOLATED THUNDERSTORMS WILL INCREASE OVER TIME AS THE
UPPER LOW AND COLD AIR ALOFT (-25C AT 500MB) MOVES OVERHEAD, THUS
INCREASING INSTABILITY. THE LATEST HRRR MODEL RUN SHOWS MOST OF THE
SHOWERS AND ISOLATED THUNDERSTORMS ALONG AND EAST OF THE CASCADES,
BUT SUSPECT IT MAY BE UNDERESTIMATING THE CONVECTIVE ACTIVITY WEST
OF THE CASCADES. THEREFORE WE`LL CONTINUE TO KEEP POPS HIGHER WEST
OF THE CASCADES INTO THIS EVENING. IN ADDITION THERE`S A CHANCE SOME
THUNDERSTORMS COULD PRODUCE GUSTY WINDS AND SMALL HAIL.
THE 12Z NAM AND GFS SHOW THE TROUGH AXIS MOVING EAST OF THE CASCADES
LATE TONIGHT AT WHICH POINT THE BULK OF THE PRECIPITATION WILL SHIFT
INTO LAKE, MODOC AND EASTERN KLAMATH COUNTY. A COLDER AIR MASS WILL
SETTLE INTO THE AREA TONIGHT, BUT THERE MAY A SUFFICIENT AMOUNT OF
CLOUD COVER REMAINING IN THE AREA, SO NIGHTTIME LOWS MAY NOT DROP AS
LOW AS WOULD BE EXPECTED. WE`LL KEEP PATCHY FROST TO THE FORECAST,
BUT GIVEN THE CLOUD COVER, DO NOT THINK THAT THIS WOULD BE A
WIDESPREAD EVENT. EVEN THEN NEAR FREEZING TEMPERATURES MAY ONLY LAST
FOR AN HOUR OR TWO NEAR DAYBREAK. SO WILL NOT ISSUE ANY HEADLINES AT
THIS TIME.
THE UPPER TROUGH WILL MOVE EAST SATURDAY MORNING AND WEAK RIDGING
BUILDS IN FROM THE SOUTHWEST. THE DEFORMATION ZONE WILL BE CONFINED
TO EASTERN LAKE AND MODOC COUNTY WITH RAIN AND HIGHER ELEVATION
RAIN/WET SNOW MIX EARLY IN THE MORNING, THEN PLAIN RAIN. THE MODELS
HAVE TRENDED FASTER WITH THE PROGRESSION OF THE UPPER LOW SATURDAY,
SO WE COULD SEE CONDITIONS DRY OUT IN THE AFTERNOON IN EASTERN LAKE
AND MODOC COUNTY. ELSEWHERE IT WILL BE DRY WITH MILDER TEMPERATURES.
CONDITIONS WILL BE DRY SATURDAY NIGHT AND THERE WILL BE LITTLE OR NO
CLOUD COVER. THIS WILL ALLOW RADIATIONAL COOLING TO TAKE PLACE AND
WERE MORE LIKELY TO HAVE WIDESPREAD FREEZING TEMPERATURES EAST OF
THE CASCADES. THEREFORE A FREEZE WATCH WILL BE IN EFFECT FOR
SATURDAY NIGHT INTO EARLY SUNDAY MORNING.
THE COOLER THAN NORMAL TEMPERATURES WILL NOT LAST LONG. THE MODELS
REMAIN IN GOOD AGREEMENT DRY AND WARMER WEATHER RETURNING SUNDAY AND
LASTING INTO MOST OF NEXT WEEK WITH THE THERMAL TROUGH SETTING UP
SUNDAY AND REMAINING A FIXTURE FOR MOST OF NEXT WEEK. IN FACT 850 MB
TEMPERATURES ARE PROJECTED TO INCREASE OVER TIME AND PEAK OUT
BETWEEN 24-26 C NEXT THURSDAY WHICH IF CORRECT COULD RESULT IN
TEMPERATURES IN THE MID TO UPPER 90S FOR THE ROGUE VALLEY.
-PETRUCELLI
&&
.AVIATION...FOR THE 04/18Z TAF CYCLE...
NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS WILL OCCUR TODAY FROM
THE CASCADES EASTWARD, WHILE SHOWERS WILL BE MORE SCATTERED EAST OF
THE COAST RANGE AND WEST OF THE CASCADES. PARTIAL TERRAIN
OBSCURATIONS AND ISOLATED MVFR CONDITIONS ARE EXPECTED IN MORE
SIGNIFICANT WEST SIDE SHOWERS THIS AFTERNOON INTO THIS EVENING. FROM
THE CASCADES EAST EXPECT HIGHER TERRAIN TO BE MOSTLY OBSCURED WITH
MVFR TO ISOLATED IFR IN HEAVIER SHOWERS AND THUNDERSTORMS. THE
FREEZING LEVEL WILL BE AT 8000 FEET TODAY AND THEN WILL FALL
OVERNIGHT TO NEAR THE SURFACE ON THE EAST SIDE. OVERNIGHT AREAS OF
MVFR AND LOCAL IFR IS EXPECTED IN LOW CLOUDS, PRIMARILY ON THE NORTH
AND NORTHWEST SLOPES AND VALLEY EDGES, AND IN THE UMPQUA BASIN. BTL
&&
.MARINE...UPDATED 845 AM PDT FRIDAY 4 SEPTEMBER 2015... NORTH WINDS
WILL CONTINUE THROUGH THE FORECAST PERIOD. A PERIOD OF SMALL CRAFT
ADVISORY LEVEL WINDS IS EXPECTED THIS AFTERNOON AND EVENING IN AN
AREA SOUTH OF CAPE BLANCO BEYOND 10 NAUTICAL MILES OF THE COAST.
WINDS THEN STRENGTHEN AGAIN SUNDAY AS A THERMAL TROUGH FORMS OVER
NORTHERN CALIFORNIA. GALES WILL BE POSSIBLE OVER THE SOUTHERN WATERS
MONDAY AND TUESDAY. SEAS WILL BE PRIMARILY WIND DRIVEN THROUGH EARLY
NEXT WEEK. BTL/WRIGHT
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...FREEZE WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY MORNING FOR
ORZ029>031.
CA...FREEZE WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY MORNING FOR
CAZ085.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR PZZ376.
$$
AREA FORECAST DISCUSSION
NWS MEDFORD OR
1139 AM PDT FRI SEP 4 2015
.DISCUSSION...THE UPPER LOW IS NOW CENTERED OVER WESTERN
WASHINGTON AND WILL CONTINUE TO MOVE SOUTH OVER THE AREA LATE
THIS AFTERNOON. A LINE OF SHOWERS AND ISOLATED THUNDERSTORMS BROKE
OUT IN ADVANCE OF AN SHORTWAVE TROUGH ROTATING AROUND THE UPPER
LOW WHICH IS NOW IN NORTHWEST CAL. SHOWERS AND ISOLATED
THUNDERSTORMS WILL INCREASE OVER TIME AS THE UPPER LOW AND COLD
AIR ALOFT (-25C AT 500MB) MOVES OVERHEAD INCREASING INSTABILITY.
THE LATEST HRRR MODEL RUN SHOWS MOST OF THE SHOWERS AND ISOLATED
THUNDERSTORMS ALONG AND EAST OF THE CASCADES, BUT SUSPECT IT MAY
BE UNDERESTIMATING THE CONVECTIVE ACTIVITY WEST OF THE CASCADES.
THEREFORE WE`LL CONTINUE TO KEEP POPS HIGHER WEST OF THE CASCADES
THIS AFTERNOON. IN ADDITION THERE`S A CHANCE SOME THUNDERSTORMS
COULD PRODUCE GUSTY WINDS AND SMALL HAIL.
THE 12Z NAM AND GFS SHOW THE TROUGH AXIS MOVING EAST OF THE
CASCADES LATE TONIGHT AT WHICH POINT THE BULK OF THE PRECIPITATION
WILL SHIFT INTO LAKE, MODOC AND EASTERN KLAMATH COUNTY. SATURDAY
IS STILL A TRANSITION DAY WITH ANY SHOWERS CONFINED TO EASTERN
LAKE COUNTY IN THE MORNING AND DRY CONDITIONS ELSEWHERE.
-PETRUCELLI
&&
.AVIATION...FOR THE 04/18Z TAF CYCLE... NUMEROUS SHOWERS AND
ISOLATED THUNDERSTORMS WILL OCCUR TODAY FROM THE CASCADES EASTWARD,
WHILE SHOWERS WILL BE MORE SCATTERED EAST OF THE COAST RANGE AND
WEST OF THE CASCADES. PARTIAL TERRAIN OBSCURATIONS AND ISOLATED MVFR
CONDITIONS ARE EXPECTED IN MORE SIGNIFICANT WEST SIDE SHOWERS THIS
AFTERNOON INTO THIS EVENING. FROM THE CASCADES EAST EXPECT HIGHER
TERRAIN TO BE MOSTLY OBSCURED WITH MVFR TO ISOLATED IFR IN HEAVIER
SHOWERS AND THUNDERSTORMS. THE FREEZING LEVEL WILL BE AT 8000 FEET
TODAY AND THEN WILL FALL OVERNIGHT TO NEAR THE SURFACE ON THE EAST
SIDE. OVERNIGHT AREAS OF MVFR AND LOCAL IFR IS EXPECTED IN LOW
CLOUDS, PRIMARILY ON THE NORTH AND NORTHWEST SLOPES AND VALLEY
EDGES, AND IN THE UMPQUA BASIN. BTL
&&
.MARINE...UPDATED 845 AM PDT FRIDAY 4 SEPTEMBER 2015... NORTH WINDS
WILL CONTINUE THROUGH THE FORECAST PERIOD. A PERIOD OF SMALL CRAFT
ADVISORY LEVEL WINDS IS EXPECTED THIS AFTERNOON AND EVENING IN AN
AREA SOUTH OF CAPE BLANCO BEYOND 10 NAUTICAL MILES OF THE COAST.
WINDS THEN STRENGTHEN AGAIN SUNDAY AS A THERMAL TROUGH FORMS OVER
NORTHERN CALIFORNIA. GALES WILL BE POSSIBLE OVER THE SOUTHERN WATERS
MONDAY AND TUESDAY. SEAS WILL BE PRIMARILY WIND DRIVEN THROUGH EARLY
NEXT WEEK. BTL/WRIGHT
&&
.PREV DISCUSSION... /ISSUED 639 AM PDT FRI SEP 4 2015/
UPDATE...PUT OUT A QUICK UPDATE JUST NOW TO INCREASE POPS ON THE
EAST SIDE AND ALLOW FOR THUNDERSTORMS OVER ALL AREAS THIS MORNING.
AIR MASS IS ALREADY DESTABILIZING QUICKLY AND WE`VE SEEN SIX
LIGHTNING STRIKES ALONG THE SISKIYOU/MODOC BORDER, AND THIS IS
WITH THE MAJORITY OF THE COLD POOL AND INSTABILITY YET TO COME
TODAY. IT ALSO WOULDN`T BE OUT OF THE QUESTION TO SEE A FEW
SNOWFLAKES OVER LAKE AND MODOC COUNTIES THIS MORNING AS SURFACE
TEMPERATURES ARE NEAR OR BELOW FREEZING. TEMP/DEWPOINT SPREAD ARE
FAIRLY HIGH, THOUGH, SO IT MAY BE JUST VIRGA OUT THERE. -WRIGHT
PREV DISCUSSION... /ISSUED 325 AM PDT FRI SEP 4 2015/
DISCUSSION...TEMPERATURES THIS MORNING HAVE BEEN QUITE COLD
RELATIVE TO NORMAL FOR THIS TIME OF YEAR, WITH TEMPERATURES EVEN
DROPPING TO THE MID 20S IN THE GENERAL REGION NEAR CHEMULT. WITH
SEVERAL MORE HOURS OF COOLING TO GO, AND CLOUDS NOT QUITE IN THE
AREA YET, THE CURRENT FROST ADVISORY SEEMS TO BE ON TRACK FOR THE
EAST SIDE. WILL THEREFORE LET THIS RIDE THROUGH THE MORNING.
TEMPERATURES WILL REMAIN MUCH COOLER THAN NORMAL TODAY, AS AMPLE
CLOUDS AND RAIN SHOULD KEEP SOLAR HEATING TO A MINIMUM.
AN UPPER LEVEL LOW, CURRENTLY LOCATED OVER THE SEATTLE AREA, WILL
DROP SOUTH TODAY, AND TAKE POSITION OVER OREGON BY THIS AFTERNOON.
AS IT DROPS SOUTH, A VERY POTENT SHORTWAVE ORBITING THE LOW WILL
PASS OVERHEAD, AND WITH THE LOWERING TEMPERATURES ALOFT, ENOUGH
INSTABILITY AND DYNAMICS SHOULD BE PRESENT TO PRODUCE SHOWERS AND
ISOLATED THUNDERSTORMS OVER THE BULK OF THE FORECAST AREA LATE
THIS MORNING INTO THIS EVENING. WHILE MOST RAINFALL AMOUNTS WILL
BE LIGHT, THERE IS A GOOD CHANCE THAT MANY LOCATIONS COULD SEE
WETTING RAINS. THIS IS PARTICULARLY TRUE EAST OF THE CASCADES,
WHERE FORCING WILL BE STRONGEST DURING THE PEAK OF DAYTIME
HEATING. OVERNIGHT, THE COLD AIR MASS WILL BEGIN TO SETTLE IN.
HOWEVER, THERE SHOULD BE AMPLE CLOUDS REMAINING IN THE AREA, SO
NIGHTTIME LOWS MAY NOT DROP AS LOW AS WOULD BE EXPECTED. HAVE
ADDED PATCHY FROST TO THE FORECAST, BUT GIVEN THE CLOUD COVER, DO
NOT THINK THAT THIS WOULD BE A WIDESPREAD EVENT, SO WILL NOT ISSUE
ANY HEADLINES AT THIS TIME.
THE LOW WILL BEGIN MOVING EAST SATURDAY MORNING, AND GRADUALLY,
SHOWERS AND CLOUDS WILL MOVE OUT OF THE FORECAST AREA AS WELL. EXPECT
THAT THE SKIES WILL BE MOSTLY CLEAR BY SATURDAY NIGHT, AIDED IN PART
TO DEVELOPING OFFSHORE FLOW DRYING OUT THE MID LEVELS. WITH THE COLD
AIR STILL AT THE SURFACE, AND NO CLOUDS TO ACT AS A BLANKET, SUSPECT
THAT THIS WILL BE THE COOLEST NIGHT OF THE WEEK. IN FACT, WIDESPREAD
FROST AND FREEZE IS LIKELY FOR THE EAST SIDE.
THESE COLD TEMPERATURES WILL NOT LAST, HOWEVER, AS UPPER LEVEL
RIDGING WILL BUILD INTO THE AREA, AND THE THERMAL TROUGH WILL RETURN
TO OUR SOUTH. OFFSHORE FLOW SHOULD KEEP THE AREA CLEAR OF CLOUDS,
AND TEMPERATURES WILL RISE TO VALUES AROUND 5 DEGREES ABOVE NORMAL
FOR THIS TIME OF YEAR BY THE MIDDLE OF NEXT WEEK. SEVERAL WAVES WILL
APPROACH THE WEST COAST DURING THIS TIME, BUT THE RIDGE SHOULD KEEP
THE TRACK OF ANY PRECIPITATION MAKING SYSTEMS WELL NORTH OF THE
FORECAST AREA. THEREFORE, FOR THE REMAINDER OF THE FORECAST TERM,
EXPECT GRADUALLY WARMING TEMPERATURES AND DRY CONDITIONS. -BPN
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...
- SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR PZZ376.
$$
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
631 PM EDT FRI SEP 4 2015
.SYNOPSIS...
HIGH PRESSURE WILL ENSURE FAIR AND MAINLY DRY WEATHER FOR LABOR
DAY WEEKEND WITH ABOVE NORMAL WARMTH AND JUST THE CHANCE OF AN
AFTERNOON OR EVENING POP-UP SHOWER OR THUNDERSTORM.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
SAME SCENARIO PLAYING OUT THIS EVENING AS THE LAST SEVERAL...WITH
DIURNALLY FORCED CONVECTION...THIS TIME MAINLY TREKKING EAST TO
WEST...SCATTERED ABOUT THE REGION. THE SHOWERS AND STORMS WILL
GRADUALLY LOSE VIGOR OVER THE NEXT SEVERAL HOURS AS WE LOSE
HEATING. UNTIL THEN...SOME OF THE STRONGER SLOW MOVING STORMS
COULD PRODUCE GUSTY WINDS...DOWNPOURS AND POSSIBLE LOCALIZED
FLOODING.
INTERESTING TO NOTE THE HRRR REALLY LIGHTS THINGS UP AFTER 00Z
OVER THE SOUTH-CENTRAL MOUNTAINS. THIS SEEMS COUNTERINTUITIVE
GIVEN THE WEAK DIURNAL FORCING.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
CONVECTION ONGOING AT THE START OF THE PERIOD MAY BE THE LAST OF
THE RAIN FOR A FEW DAYS. EXPECT SHRA/TSRA TO WANE THROUGH THE
EVENING. THE INTERESTING/CHALLENGING PART OF THIS FORECAST MAY BE
THE CLOUD COVER TONIGHT AND SAT MORNING AND RESULTANT MINS/MAXES.
THE NAM IS PRETTY AGGRESSIVE IN ADVECTING LOW CRUD/STRATUS IN FROM
THE EAST/SOUTHEAST TONIGHT AND PILING IT UP IN THE MOUNTAINS.
HOWEVER...THE GFS IS NOT SO BULLISH ON THE LOW LEVEL MOISTURE. IT
STILL MAKES LOWER CLOUDS /BELOW 8H/ BUT IS MORE NORTHEASTERLY WITH
THE WINDS ON THE SRN PERIPHERY OF THE HIGH. THUS...MORE DRY AIR IS
SEEN ADVECTING INTO THE AREA IN THE GFS SOLUTION. THIS ALLOWS THE
MARITIME AIR/CLOUDS TO DRY OUT QUICKLY WITH MINIMAL MIXING. THE
TROUBLE WITH THE DRIER SOLUTION IS THAT WE HAVE BEEN PRETTY MUGGY
AND THE MDL OMEGA FIELDS DO NOT PORTRAY SOME OVERWHELMING DOWN-
MOTION. IN FACT...THEY ARE PRETTY NEUTRAL. VERY ISOLATED DIURNAL
CONVECTION IS POSSIBLE IN THE FAR WEST/SOUTHWEST ON SAT...BUT THE
PWATS WILL BE MUCH LOWER - ONLY RANGING FROM 1 INCH IN THE NE TO
1.25 IN THE WEST. AT THIS POINT...THE MOST PROBABLE SOLUTION IN
OUR WEAK FLOW IS THAT THE SFC HIGH STAYS UP OVER NEW ENGLAND AND
THE DRY AIR MAKES ONLY SLOW PROGRESS TO MOVE ACROSS THE REGION.
WILL KEEP IT MORE CLOUDY AND COOLER IN THE FIRST PART OF THE DAY
AND KEEP MAXES SHORT OF GFS-MOS GUIDANCE.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
A RATHER LARGE AREA OF HIGH PRESSURE AT THE SFC...AND A SLOWLY
FLATTENING UPPER RIDGE OVER THE EASTERN U.S...SHOULD MAINTAIN DRY
WEATHER SATURDAY NIGHT THROUGH MONDAY. PRECIPITABLE WATER VALUES
WILL RANGE FROM BELOW NORMAL AND ONLY AROUND ONE-HALF OF AN INCH
ACROSS FAR NERN PENN...TO SLIGHTLY ABOVE NORMAL ALONG THE SE SHORE
OF LAKE ERIE SUNDAY SATURDAY NIGHT INTO SUNDAY NIGHT. A FEW SHOWERS
OR EVEN A BRIEF TSRA COULD BRUSH OUR FAR NW ZONES DURING THIS
INITIAL 24 HOURS OF THE LONG TERM PERIOD...BUT POPS WILL BE LESS
THAN 25 PERCENT.
AN INITIAL...WEAK...COLD FRONT WILL SLIDE SLOWLY TO THE ESE FROM THE
GREAT LAKES/MIDWEST STATES. THIS FEATURE COULD BRING SOME ISOLATED
SHRA/TSRA TO OUR NW ZONES BEGINNING TUESDAY AFTERNOON AND EVENING.
A SLOWLY AMPLIFYING...BROAD TROUGH FROM THE NRN PLAINS THROUGH THE
NE U.S. WEDNESDAY AFTERNOON INTO NEXT WEEKEND WILL PUSH A
SECOND...STRONGER CFRONT EAST ACROSS THE COMMONWEALTH WEDNESDAY
NIGHT AND THURSDAY.
THIS PATTERN TRANSITION WILL BRING A FEW OPPORTUNITIES FOR
SHOWERS AND THUNDERSTORMS...ALBEIT MAINLY OF THE SCATTERED
AFTERNOON AND EVENING VARIETY.
12Z GEFS AND 12Z EC ARE IN GOOD AGREEMENT ON THE LOCATION OF THIS
TROUGH AXIS /FROM LAKE SUPERIOR TO THE MID MISS VALLEY AT 00Z
SAT/...THOUGH AS ONE WOULD EXPECT...THE ENSEMBLE MEAN DAMPENS OUT
THE AMPLITUDE OF THE TROUGH COMPARED TO THE EC.
DETAILS IN THE TIMING OF ANY SPECIFIC SHORTWAVES ROTATING THROUGH
THIS AMPLYIFYING TROUGH ARE SIMPLY TOO MUDDY AT THIS TIME RANGE.
ONE THING MORE CERTAIN IN THIS MEDIUM RANGE FORECAST IS THE COOLING
TEMPS FOR THE LATTER HALF OF THE WEEK AND NEXT WEEKEND...WHEN BOTH
MAX AND MIN TEMPS COULD BE UP TO SEVERAL DEG F BELOW NORMAL
/ESPECIALLY OVER THE NRN AND WESTERN MTNS OF THE STATE...WHERE MORE
CLOUDS AND COOLER TEMPS ALOFT WILL BE FOUND/.
&&
.AVIATION /22Z FRIDAY THROUGH WEDNESDAY/...
GENERALLY VFR CONDS EXPECTED THROUGH EARLY EVENING HOURS...SAVE
WHERE ISOLATED SHRA/TSRA MAY IMPACT AIRFIELDS...MAINLY ACROSS
SOUTHERN PA. A BRIEF VIS REDUCTION IS POSSIBLE IN A FEW SPOTS FROM
THESE STORMS...MAINLY THRU 05/01Z.
A MOIST SERLY FLOW BEHIND THE COLD FRONT WILL LIKELY PRODUCE SOME
LOW CIGS ACROSS THE MTNS OF CENTRAL PA TONIGHT AND EARLY SAT AM.
SFC HIGH PRESSURE WILL BUILD INTO THE REGION FOR THE WEEKEND.
OUTLOOK...
SAT...AM LOW CIGS POSS...MAINLY KBFD/KJST.
SUN-TUE...PATCHY AM FOG POSS...MAINLY KBFD/KIPT.
WED...COLD FROPA WITH SCT SHRA/TSRA.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE/GARTNER
NEAR TERM...LA CORTE/GARTNER
SHORT TERM...DANGELO/GARTNER
LONG TERM...LAMBERT
AVIATION...GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
307 PM EDT FRI SEP 4 2015
.SYNOPSIS...
ABOVE NORMAL TEMPERATURES WILL CONTINUE INTO NEXT WEEK WITH
GRADUALLY DECREASING HUMIDITY LEVELS. ISOLATED SHOWERS AND
THUNDERSTORMS ARE POSSIBLE INTO EARLY THIS EVENING. HIGH PRESSURE
WILL ENSURE FAIR AND DRY WEATHER FOR LABOR DAY WEEKEND.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
ISOLATED SHOWERS AND THUNDERSTORMS AGAIN POPPING THIS AFTN AS
EXPECTED...MAINLY ACROSS SRN PA. THIS WILL CONTINUE FOR THE NEXT
SEVERAL HOURS WITH ANY SLOW MOVING STORMS PRODUCING BRIEF HEAVY
DOWNPOURS.
GUIDANCE INCLUDING LATEST HRRR IMAGERY SHOWS A CONVERGENCE OF
ACTIVITY THROUGH THE LOWER SUSQ VALLEY SOUTH CENTRAL MTNS AS WEAK
BACKDOOR COLD FRONT DROPS SOUTH...AND EASTERLY FLOW ON SRN END OF
SFC HIGH CONCENTRATES MOISTURE WESTWARD INTO THE REGION.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM SATURDAY/...
CONVECTION ONGOING AT THE START OF THE PERIOD MAY BE THE LAST OF
THE RAIN FOR A FEW DAYS. EXPECT SHRA/TSRA TO WANE THROUGH THE
EVENING. THE INTERESTING/CHALLENGING PART OF THIS FORECAST MAY BE
THE CLOUD COVER TONIGHT AND SAT MORNING AND RESULTANT MINS/MAXES.
THE NAM IS PRETTY AGGRESSIVE IN ADVECTING LOW CRUD/STRATUS IN FROM
THE EAST/SOUTHEAST TONIGHT AND PILING IT UP IN THE MOUNTAINS.
HOWEVER...THE GFS IS NOT SO BULLISH ON THE LOW LEVEL MOISTURE. IT
STILL MAKES LOWER CLOUDS /BELOW 8H/ BUT IS MORE NORTHEASTERLY WITH
THE WINDS ON THE SRN PERIPHERY OF THE HIGH. THUS...MORE DRY AIR IS
SEEN ADVECTING INTO THE AREA IN THE GFS SOLUTION. THIS ALLOWS THE
MARITIME AIR/CLOUDS TO DRY OUT QUICKLY WITH MINIMAL MIXING. THE
TROUBLE WITH THE DRIER SOLUTION IS THAT WE HAVE BEEN PRETTY MUGGY
AND THE MDL OMEGA FIELDS DO NOT PORTRAY SOME OVERWHELMING DOWN-
MOTION. IN FACT...THEY ARE PRETTY NEUTRAL. VERY ISOLATED DIURNAL
CONVECTION IS POSSIBLE IN THE FAR WEST/SOUTHWEST ON SAT...BUT THE
PWATS WILL BE MUCH LOWER - ONLY RANGING FROM 1 INCH IN THE NE TO
1.25 IN THE WEST. AT THIS POINT...THE MOST PROBABLE SOLUTION IN
OUR WEAK FLOW IS THAT THE SFC HIGH STAYS UP OVER NEW ENGLAND AND
THE DRY AIR MAKES ONLY SLOW PROGRESS TO MOVE ACROSS THE REGION.
WILL KEEP IT MORE CLOUDY AND COOLER IN THE FIRST PART OF THE DAY
AND KEEP MAXES SHORT OF GFS-MOS GUIDANCE.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
A RATHER LARGE AREA OF HIGH PRESSURE AT THE SFC...AND A SLOWLY
FLATTENING UPPER RIDGE OVER THE EASTERN U.S...SHOULD MAINTAIN DRY
WEATHER SATURDAY NIGHT THROUGH MONDAY. PRECIPITABLE WATER VALUES
WILL RANGE FROM BELOW NORMAL AND ONLY AROUND ONE-HALF OF AN INCH
ACROSS FAR NERN PENN...TO SLIGHTLY ABOVE NORMAL ALONG THE SE SHORE
OF LAKE ERIE SUNDAY SATURDAY NIGHT INTO SUNDAY NIGHT. A FEW SHOWERS
OR EVEN A BRIEF TSRA COULD BRUSH OUR FAR NW ZONES DURING THIS
INITIAL 24 HOURS OF THE LONG TERM PERIOD...BUT POPS WILL BE LESS
THAN 25 PERCENT.
AN INITIAL...WEAK...COLD FRONT WILL SLIDE SLOWLY TO THE ESE FROM THE
GREAT LAKES/MIDWEST STATES. THIS FEATURE COULD BRING SOME ISOLATED
SHRA/TSRA TO OUR NW ZONES BEGINNING TUESDAY AFTERNOON AND EVENING.
A SLOWLY AMPLIFYING...BROAD TROUGH FROM THE NRN PLAINS THROUGH THE
NE U.S. WEDNESDAY AFTERNOON INTO NEXT WEEKEND WILL PUSH A
SECOND...STRONGER CFRONT EAST ACROSS THE COMMONWEALTH WEDNESDAY
NIGHT AND THURSDAY.
THIS PATTERN TRANSITION WILL BRING A FEW OPPORTUNITIES FOR
SHOWERS AND THUNDERSTORMS...ALBEIT MAINLY OF THE SCATTERED
AFTERNOON AND EVENING VARIETY.
12Z GEFS AND 12Z EC ARE IN GOOD AGREEMENT ON THE LOCATION OF THIS
TROUGH AXIS /FROM LAKE SUPERIOR TO THE MID MISS VALLEY AT 00Z
SAT/...THOUGH AS ONE WOULD EXPECT...THE ENSEMBLE MEAN DAMPENS OUT
THE AMPLITUDE OF THE TROUGH COMPARED TO THE EC.
DETAILS IN THE TIMING OF ANY SPECIFIC SHORTWAVES ROTATING THROUGH
THIS AMPLYIFYING TROUGH ARE SIMPLY TOO MUDDY AT THIS TIME RANGE.
ONE THING MORE CERTAIN IN THIS MEDIUM RANGE FORECAST IS THE COOLING
TEMPS FOR THE LATTER HALF OF THE WEEK AND NEXT WEEKEND...WHEN BOTH
MAX AND MIN TEMPS COULD BE UP TO SEVERAL DEG F BELOW NORMAL
/ESPECIALLY OVER THE NRN AND WESTERN MTNS OF THE STATE...WHERE MORE
CLOUDS AND COOLER TEMPS ALOFT WILL BE FOUND/.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
GENERALLY VFR CONDS EXPECTED THROUGH EARLY EVENING HOURS...SAVE
WHERE ISOLATED SHRA/TSRA MAY IMPACT AIRFIELDS...MAINLY ACROSS
SOUTHERN PA. A BRIEF VIS REDUCTION IS POSSIBLE IN A FEW SPOTS FROM
THESE STORMS...MAINLY THRU 05/01Z.
A MOIST SERLY FLOW BEHIND THE COLD FRONT WILL LIKELY PRODUCE SOME
LOW CIGS ACROSS THE MTNS OF CENTRAL PA TONIGHT AND EARLY SAT AM.
SFC HIGH PRESSURE WILL BUILD INTO THE REGION FOR THE WEEKEND.
OUTLOOK...
SAT...AM LOW CIGS POSS...MAINLY KBFD/KJST.
SUN-TUE...PATCHY AM FOG POSS...MAINLY KBFD/KIPT.
WED...COLD FROPA WITH SCT SHRA/TSRA.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/GARTNER
NEAR TERM...GARTNER
SHORT TERM...DANGELO/GARTNER
LONG TERM...LAMBERT
AVIATION...GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
245 PM EDT FRI SEP 4 2015
.SYNOPSIS...
ABOVE NORMAL TEMPERATURES WILL CONTINUE INTO NEXT WEEK WITH
GRADUALLY DECREASING HUMIDITY LEVELS. ISOLATED SHOWERS AND
THUNDERSTORMS ARE POSSIBLE INTO EARLY THIS EVENING. HIGH PRESSURE
WILL ENSURE FAIR AND DRY WEATHER FOR LABOR DAY WEEKEND.
&&
.NEAR TERM /UNTIL 9 PM THIS EVENING/...
ISOLATED SHOWERS AND THUNDERSTORMS AGAIN POPPING THIS AFTN AS
EXPECTED...MAINLY ACROSS SRN PA. THIS WILL CONTINUE FOR THE NEXT
SEVERAL HOURS WITH ANY SLOW MOVING STORMS PRODUCING BRIEF HEAVY
DOWNPOURS.
GUIDANCE INCLUDING LATEST HRRR IMAGERY SHOWS A CONVERGENCE OF
ACTIVITY THROUGH THE LOWER SUSQ VALLEY SOUTH CENTRAL MTNS AS WEAK
BACKDOOR COLD FRONT DROPS SOUTH...AND EASTERLY FLOW ON SRN END OF
SFC HIGH CONCENTRATES MOISTURE WESTWARD INTO THE REGION.
&&
.SHORT TERM /9 PM THIS EVENING THROUGH 6 PM SATURDAY/...
CONVECTION ONGOING AT THE START OF THE PERIOD MAY BE THE LAST OF
THE RAIN FOR A FEW DAYS. EXPECT SHRA/TSRA TO WANE THROUGH THE
EVENING. THE INTERESTING/CHALLENGING PART OF THIS FORECAST MAY BE
THE CLOUD COVER TONIGHT AND SAT MORNING AND RESULTANT MINS/MAXES.
THE NAM IS PRETTY AGGRESSIVE IN ADVECTING LOW CRUD/STRATUS IN FROM
THE EAST/SOUTHEAST TONIGHT AND PILING IT UP IN THE MOUNTAINS.
HOWEVER...THE GFS IS NOT SO BULLISH ON THE LOW LEVEL MOISTURE. IT
STILL MAKES LOWER CLOUDS /BELOW 8H/ BUT IS MORE NORTHEASTERLY WITH
THE WINDS ON THE SRN PERIPHERY OF THE HIGH. THUS...MORE DRY AIR IS
SEEN ADVECTING INTO THE AREA IN THE GFS SOLUTION. THIS ALLOWS THE
MARITIME AIR/CLOUDS TO DRY OUT QUICKLY WITH MINIMAL MIXING. THE
TROUBLE WITH THE DRIER SOLUTION IS THAT WE HAVE BEEN PRETTY MUGGY
AND THE MDL OMEGA FIELDS DO NOT PORTRAY SOME OVERWHELMING DOWN-
MOTION. IN FACT...THEY ARE PRETTY NEUTRAL. VERY ISOLATED DIURNAL
CONVECTION IS POSSIBLE IN THE FAR WEST/SOUTHWEST ON SAT...BUT THE
PWATS WILL BE MUCH LOWER - ONLY RANGING FROM 1 INCH IN THE NE TO
1.25 IN THE WEST. AT THIS POINT...THE MOST PROBABLE SOLUTION IN
OUR WEAK FLOW IS THAT THE SFC HIGH STAYS UP OVER NEW ENGLAND AND
THE DRY AIR MAKES ONLY SLOW PROGRESS TO MOVE ACROSS THE REGION.
WILL KEEP IT MORE CLOUDY AND COOLER IN THE FIRST PART OF THE DAY
AND KEEP MAXES SHORT OF GFS-MOS GUIDANCE.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
NOT MUCH TO CHANGE IN A SLOWLY EVOLVING EXTENDED FORECAST. HIGH
PRESSURE SHOULD MAINTAIN DRY WEATHER SUNDAY-MONDAY. LEAD COLD
FRONT ADVANCING EWD FROM THE GREAT LAKES/MIDWEST AND POTENTIAL
ONSHORE FLOW MSTR MAY IMPACT THE FCST BY TUESDAY WITH SCT TSTMS
POSS...BUT A CONSENSUS SOLUTION HOLDS BACK HIGHER POPS UNTIL WED
OR MAYBE EVEN THU IN ASSOCIATION WITH A STRONGER SHORTWAVE/SFC
COLD FRONT. SO TIMING DIFFS WILL NEED TO BE RESOLVED AS THE RIDGE
SLOWLY BREAKS DOWN.
THE GLOBAL NUMERICAL MODELS/ENSEMBLES ARE COMING INTO BETTER
AGREEMENT ON A PATTERN CHANGE DURING THE SECOND HALF OF NEXT WEEK
WITH A SHUFFLING OF THE LONGWAVE FLOW ALLOWING EWD PROGRESSION OF
THE WESTERN TROUGH INTO THE CENTRAL STATES AND RECENT RIDGE OVER
THE EASTERN UNITED STATES OFF THE COAST INTO THE WRN ATLC. THIS
SHOULD EVENTUALLY BRING AN END TO THE RECENT HOT/DRY SPELL. A
RETURN TO SEASONAL TEMPERATURES AND MORE ACTIVE PCPN PATTERN
SEEMS PROBABLE BY NEXT WEEKEND IN THE NEW FLOW REGIME.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
GENERALLY VFR CONDS EXPECTED THROUGH EARLY EVENING HOURS...SAVE
WHERE ISOLATED SHRA/TSRA MAY IMPACT AIRFIELDS...MAINLY ACROSS
SOUTHERN PA. A BRIEF VIS REDUCTION IS POSSIBLE IN A FEW SPOTS FROM
THESE STORMS...MAINLY THRU 05/01Z.
A MOIST SERLY FLOW BEHIND THE COLD FRONT WILL LIKELY PRODUCE SOME
LOW CIGS ACROSS THE MTNS OF CENTRAL PA TONIGHT AND EARLY SAT AM.
SFC HIGH PRESSURE WILL BUILD INTO THE REGION FOR THE WEEKEND.
OUTLOOK...
SAT...AM LOW CIGS POSS...MAINLY KBFD/KJST.
SUN-TUE...PATCHY AM FOG POSS...MAINLY KBFD/KIPT.
WED...COLD FROPA WITH SCT SHRA/TSRA.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/GARTNER
NEAR TERM...GARTNER
SHORT TERM...DANGELO/GARTNER
LONG TERM...RXR/STEINBUGL
AVIATION...GARTNER
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1246 PM CDT FRI SEP 4 2015
.DISCUSSION...SEE 18Z AVIATION DISCUSSION.
&&
.AVIATION...HAVE VCSH AND/OR TEMPO SHRA IN THE TERMINALS FOR ON-
GOING CONVECTION AT ALL BUT KLRD...BASED ON RADAR AND HRRR MODEL
DATA. EXPECT CONVECTION TO BE GONE BY 05/000Z IF NOT EARLIER.
THINK CONVECTION WILL MAINLY BE SHOWERS SO DID NOT MENTION THUNDER
(WILL HAVE TO MONITOR RADAR THOUGH). DID NOT INCLUDE CONVECTION AT
KLRD AS THINK MOST PRECIP SHOULD STAY EAST OF TERMINAL. OUTSIDE OF
CONVECTION...VFR THROUGH 05/10Z THEN COULD EITHER SEE SOME MVFR
CIGS AT KLRD AND VSBYS AT KALI/KVCT BETWEEN 10Z-14Z (COULD EVEN
HAVE TEMPO IFR BR AT KALI/KVCT). SHOULD BE LESS CONVECTION ON
SATURDAY BUT DID HAVE A VCSH AT KVCT WHERE MOISTURE IS BETTER AND
CONVECTION FROM GULFMEX HAS THE BEST CHANCE OF REACHING A TERMINAL
(CONFIDENCE TOO LOW FOR A PROB30). WINDS GENERALLY SSE AND LESS
THAN 11 KNOTS BUT COULD BE GUSTY THIS AFTERNOON KCRP...KALI AND
KLRD TERMINALS.
&&
.PREV DISCUSSION... /ISSUED 1001 AM CDT FRI SEP 4 2015/
DISCUSSION...MAIN CHANGE WAS TO CHANGE MENTION OF RAIN FROM
PROBABILITY TO COVERAGE (E.G. CHANCE TO SCATTERED). FEW MINOR
ADJUSTMENTS TO WINDS. TEMPERATURES LOOK FINE. CRP SOUNDING
SHOWING PWATS NEAR 2 INCHES SO ISOLATED TO SCATTERED LOOKS
REASONABLE AND NO EXPECT LOWER COVERAGE LATER THIS AFTERNOON AS
MIXING PRECLUDES DEEP CONVECTION. UPDATED PRODUCTS OUT.
PREV DISCUSSION... /ISSUED 641 AM CDT FRI SEP 4 2015/
DISCUSSION...UPDATED FOR 12Z AVIATION.
AVIATION...MVFR CIGS/VSBYS WILL STILL BE A POSSIBILITY AT
LRD/ALI/VCT EARLY THIS MORNING...BEFORE RETURNING TO VFR LEVELS
BY 15Z. ISOLATED TO SCATTERED SHOWERS AND STORMS MAY OCCUR TODAY
ACROSS SOUTH TEXAS...AND HAVE INCLUDED ONLY VCSH REMARKS AT
ALI/VCT/CRP FOR NOW. ANY CONVECTION THAT DEVELOPS SHOULD DISSIPATE
WITH THE LOSS OF DAYTIME HEATING. WINDS WILL BE MOSTLY OUT OF THE
SSE AND SE TODAY WITH A FEW GUSTS AROUND 20 KNOTS DURING THE
AFTERNOON HOURS. PATCHY FOG MAY DEVELOP LATE TONIGHT INTO EARLY
SATURDAY MORNING...BUT CONFIDENCE IS NOT GREAT ENOUGH TO MENTION
IN THE FORECAST.
PREV DISCUSSION... /ISSUED 346 AM CDT FRI SEP 4 2015/
SHORT TERM (TODAY THROUGH SATURDAY)...DESPITE UPPER LEVEL RIDGE
BUILDING OVER THE AREA...LOW CHANCES FOR SHOWERS AND A FEW STORMS
WILL EXIST DURING THE SHORT TERM. MOISTURE WILL BE SUFFICIENT
TODAY WITH PW VALUES AROUND 1.9 TO 2.0 INCHES. ISOLATED CONVECTION
HAS ALL READY DEVELOPED EARLY THIS MORNING OVER THE GULF WATERS
INTO THE NORTHERN COASTAL BEND. ADDITIONAL ACTIVITY IS EXPECTED IS
EXPECTED LATER THIS MORNING...AND THEN SPREAD INLAND WITH THE SEA
BREEZE. SHOWERS AND STORMS SHOULD BE MOSTLY DIURNALLY DRIVEN AND
THEN DISSIPATE WITH THE LOSS OF DAYTIME HEATING THIS EVENING.
TEMPERATURES TODAY WILL BE SLIGHTLY ABOVE NORMAL FOR THIS TIME OF
YEAR...WITH HIGHS AROUND 100 OVER THE RIO GRANDE PLAINS TO LOWER
90S ACROSS THE VICTORIA CROSSROADS. SIMILAR TO THE LAST FEW
DAYS...CONVECTION MAY REDEVELOP LATE IN THE NIGHT OVER THE GULF
WATERS AND MOVE INLAND DURING THE MORNING/EARLY AFTERNOON HOURS.
VERY WARM CONDITIONS WILL BE COMMON ON SATURDAY WITH HIGHS IN THE
LOWER 100S OUT WEST AND LOW/MID 90S ACROSS THE EAST.
LONG TERM (SATURDAY NIGHT THROUGH THURSDAY)...MIDLEVEL RIDGE BUILDS
IN FROM THE WEST WITH LESS MOISTURE AVAILABILITY FOR THE END OF THE
WEEKEND. THE RIDGE FLATTENS AND SHIFTS SOUTHWEST EARLY NEXT WEEK
UNDER A SOUTHWARD PROGRESSING TROUGH MOVING ACROSS THE CENTRAL
PLAINS...AND FROM A DEVELOPING CUT OFF LOW ACROSS THE SOUTHEASTERN
STATES RETROGRADING INTO THE WESTERN GULF. A SLIGHTLY WEAKENED CAP
AND MOISTURE INCREASING ACROSS THE EASTERN HALF OF THE CWA SHOULD
LEAD TO AT LEAST ISOLATED ACTIVITY DEVELOPMENT MONDAY THROUGH
THURSDAY IN THE TYPICAL SUMMER PATTERN WITH NOCTURNAL GULF ACTIVITY
MOVING INLAND AS THE DAY PROGRESSES. OVERALL...MOST LOCATIONS SHOULD
REMAIN DRY. ANY SHOWER ACTIVITY IS EXPECTED TO WANE DURING THE
EVENING HOURS. AS FOR TEMPERATURES...SLIGHTLY ABOVE NORMAL CAN BE
EXPECTED...WITH HIGHS NEAR THE MID 90S ACROSS THE EAST...TO NEAR 100
DEGREES OVER THE RIO GRANDE PLAINS.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 93 78 94 77 95 / 30 10 20 10 10
VICTORIA 92 75 94 75 96 / 40 10 20 10 10
LAREDO 99 77 102 77 102 / 10 10 10 10 0
ALICE 96 75 98 75 99 / 30 10 10 10 10
ROCKPORT 90 79 91 79 91 / 40 20 20 10 10
COTULLA 99 75 101 76 102 / 10 10 10 10 0
KINGSVILLE 95 77 96 76 97 / 30 10 10 10 10
NAVY CORPUS 89 80 90 79 91 / 30 20 20 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
GW/86...AVIATION
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
604 PM CDT FRI SEP 4 2015
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 343 PM CDT FRI SEP 4 2015
A WARM FRONT...SITUATED NEAR THE MISSISSIPPI RIVER WILL
GRADUALLY LIFT NORTHEAST LATE THIS AFTERNOON THROUGH TONIGHT.
ISOLATED SHOWERS AND A FEW THUNDERSTORMS ARE POSSIBLE ALONG THIS
FRONT...MAINLY THROUGH 7 PM. WITH ONLY WEAK SHEAR IN
PLACE...SEVERE WEATHER IS NOT EXPECTED.
A WEAK SHORTWAVE WAS MOVING EAST ACROSS SOUTHWEST MINNESOTA/WESTERN
IOWA THIS AFTERNOON PRODUCING A FEW SHOWERS AND ISOLATED
THUNDERSTORMS. THIS WAVE IS EXPECTED TO PUSH EAST ACROSS THE
FORECAST AREA TONIGHT BRINGING VERY SLIGHT CHANCES FOR SHOWERS AND
POSSIBLY A THUNDERSTORM. LOOKING AT FORECAST SOUNDINGS ACROSS THE
AREA TONIGHT THEY ARE SHOWING DRY AIR FROM JUST ABOVE THE SURFACE
THROUGH AROUND 11KFT FT. AIR PARCELS WOULD HAVE TO BE LIFTED FROM
THIS LEVEL TO GET CONVECTION TO GO. BECAUSE OF THIS...THERE IS
VERY LIMITED CAPE TO WORK WITH. THE MOST LIKELY OUTCOME TONIGHT
WILL BE SOME ALTOCUMULUS CASTELLANUS. THE CONVECTIVE ALLOWING
MODELS CONTINUE TO GENERATE SCATTERED SIMULATED RADAR RETURNS
TONIGHT SO WILL CONTINUE WITH A SLIGHT CHANCE FOR SHOWERS AND
STORMS ACROSS MUCH OF THE FORECAST AREA OVERNIGHT. THE WARM FRONT
WILL LIFT TO THE NORTHEAST OVERNIGHT INTO SATURDAY MORNING. WARM
SOUTHERLY FLOW WILL BE THE RULE ON SATURDAY ACROSS THE FORECAST
AREA WITH HIGHS CLIMBING INTO THE MID TO UPPER 80S. A FEW
MISSISSIPPI RIVER VALLEY LOCATIONS COULD REACH THE 90 TO 93 DEGREE
MARK.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 343 PM CDT FRI SEP 4 2015
UPPER LEVEL RIDGE AXIS STARTS TO EDGE EAST SATURDAY NIGHT INTO
SUNDAY AS FLOW ALOFT STARTS TO TRANSITION TO SOUTHWEST AS A TROUGH
EDGES EAST ACROSS THE WESTERN CONUS. AN EMBEDDED SHORTWAVE SLIDES
ACROSS MINNESOTA SATURDAY NIGHT INTO SUNDAY MORNING AND COULD JUST
BRUSH NORTHWEST SECTIONS OF THE FORECAST AREA WITH A COUPLE OF
SHOWERS AND THUNDERSTORMS . OTHERWISE THE PRESSURE GRADIENT WILL
CONTINUE TO TIGHTEN ACROSS THE REGION ON SUNDAY AS A COLD FRONT
APPROACHES. VERY WARM AIR AND DEEP MIXING AHEAD OF THE FRONT WILL
ALLOW TEMPERATURES TO SOAR INTO THE UPPER 80S TO LOWER 90S. A FEW
MID 90S ARE POSSIBLE ACROSS PORTIONS OF SOUTHWEST WISCONSIN. HEAT
INDEX VALUES LOOK TO CLIMB INTO THE MID TO UPPER 90S DURING THE
AFTERNOON HOURS...ESPECIALLY ALONG THE MISSISSIPPI RIVER AND
WISCONSIN RIVER VALLEYS...INTO CENTRAL WISCONSIN. SHOWERS AND STORMS
ARE EXPECTED TO DEVELOP ALONG THE COLD FRONT LATE SUNDAY AFTERNOON
ACROSS NORTHEAST IOWA....SOUTHEAST MINNESOTA AND NORTHWEST
WISCONSIN. 0-1KM MUCAPE VALUES LOOK TO CLIMB INTO THE 1200 TO 18000
J/KG RANGE WEST OF THE MISSISSIPPI RIVER. 0-3 KM BULK SHEAR
VALUES ARE ONLY EXPECTED TO BE IN THE 15 TO 20 KT RANGE. GIVEN THE
CAPE VALUES WE CANNOT RULE OUT A FEW STRONG TO POSSIBLY SEVERE
STORMS WITH THE MAIN THREATS OF STRONG WIND GUSTS...AT LEAST FROM
LATE AFTERNOON INTO EARLY EVENING BEFORE THE CAPE STARTS TO WANE.
THE FRONT WILL PUSH EAST ACROSS THE FORECAST AREA DURING THE
OVERNIGHT HOURS WITH SHOWERS AND STORMS EXPECTED ALONG IT. THE
STORMS WILL PROBABLY BE ON A WEAKENING TREND AS THEY MAKE IT INTO
WESTERN AND CENTRAL WISCONSIN. ANOTHER ITEM WORTH NOTING IS THAT
THE JET POSITION RELATIVE TO THE COLD FRONT. THE 300 MB JET IS
LAGGING BEHIND THE FRONT AND ORIENTED PARALLEL WHICH ISN/T
FAVORABLE FOR DEEP LIFT. MUCH MORE COMFORTABLE
TEMPERATURES/DEWPOINTS MOVE INTO THE REGION IN THE WAKE OF THE
FRONT FOR MONDAY INTO TUESDAY. THERE ARE CHANCES FOR SHOWERS AND
STORMS AGAIN ON TUESDAY AS THE FRONT HANGS UP ACROSS CENTRAL IOWA
INTO NORTHERN ILLINOIS WITH SOME MOISTURE POSSIBLY OVERRUNNING
THE FRONT. WILL HAVE TO KEEP A CLOSE EYE ON EXACTLY WHERE THIS
FRONT DECIDES TO SET UP. THERE ARE LOW CHANCES FOR SHOWERS AND
STORM FROM WEDNESDAY INTO FRIDAY BUT FORECAST CONFIDENCE IS LOW AT
THIS TIME...SO LEANED TOWARD A MODEL CONSENSUS BLEND.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 604 PM CDT FRI SEP 4 2015
BAND OF APPROACHING SHOWERS OR SPRINKLES FROM NORTH CENTRAL IOWA
LOOKS TO BE FALLING OUT OF A MID LEVEL DECK. THESE SHOWERS ARE
ASSOCIATED WITH A SHORT WAVE TROUGH THAT EXTENDS FROM EASTERN
NORTH DAKOTA INTO NORTHWEST IOWA. THE 04.21Z RAP CONTINUES TO MOVE
THIS SHORT WAVE TROUGH SLOWLY TO THE NORTHEAST THIS EVENING WHICH
SHOULD ALLOW THE CLOUDS TO SPREAD OVER BOTH SITES FOR A VFR
CEILING. THE 04.12Z HI-RES NMM PROBABLY HAS THE BEST HANDLE ON THE
SHOWERS AND SUGGESTS THAT THE SOUTHERN END OF THESE MAY FALL APART
AS THE BEST FORCING REMAINS WELL TO THE NORTH CLOSER TO THE
STRONGER PORTION OF THE SHORT WAVE TROUGH OVER NORTH DAKOTA. WITH
THIS SCENARIO SOME SPRINKLES WOULD BE ABOUT ALL THAT WOULD BE
POSSIBLE THIS EVENING. FOR NOW...WILL NOT INCLUDE ANY MENTION OF
SHOWERS...BUT WILL MONITOR RADAR TRENDS AS KRST COULD POSSIBLY SEE
SOMETHING IF THESE HOLD TOGETHER. NOT EXPECTING ANY FOG TO FORM
OVERNIGHT WITH THE CLOUDS OVER THE AREA AND DECENT MIXING EXPECTED
IN THE LOW LEVELS. SOME GUSTY SOUTH WINDS EXPECTED SATURDAY AT
KRST AS THE GRADIENT BECOMES A LITTLE TIGHTER AND WITH A WELL
MIXED BOUNDARY LAYER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...04
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
444 PM MDT FRI SEP 4 2015
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 348 PM MDT FRI SEP 4 2015
ANOTHER ROUND OF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL
MOVE ACROSS MUCH OF THE FORECAST AREA THIS AFTERNOON AND EVENING.
GUSTY WINDS WILL ACCOMPANY SOME SHOWERS AND THUNDERSTORMS. WINDS
TO NEAR 50 MPH HAVE ALREADY BEEN MEASURED AT LARAMIE AND NEAR
BAGGS WYOMING. GUSTY WINDS WILL BE THE MAIN CONCERN OVER THE NEXT
FEW HOURS...OTHERWISE SEVERE STORMS ARE NOT A THREAT TODAY.
SOUTHWEST FLOW ALOFT WILL REMAIN IN PLACE SATURDAY WITH MORE
CHANCES FOR SHOWERS AND THUNDERSTORMS. THE OVERALL COVERAGE WILL
BE MINIMAL AND NOT EXPECTING SEVERE STORMS BUT A FEW STRONG WIND
GUSTS WILL ONCE AGAIN BE POSSIBLE IN THE AFTERNOON.
CHANGES WILL TAKE PLACE SATURDAY NIGHT INTO SUNDAY AS A
RELATIVELY STRONG DISTURBANCE LIFTS NORTHEAST ACROSS MONTANA AND
INTO SOUTHERN CANADA. AN ASSOCIATED COLD FRONT WILL MOVE ACROSS
THE FORECAST AREA LATE SATURDAY NIGHT...BRINGING COOLER
TEMPERATURES AND WINDY CONDITIONS SUNDAY.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 324 PM MDT FRI SEP 4 2015
MONDAY-MONDAY NIGHT:
LATEST WATER VAPOR LOOP WAS SHOWING THE UPPER LEVEL TROF SPINNING
IN THE NORTHWEST U.S. MEANWHILE...ANOTHER SHORTWAVE WAS DIVING
SOUTHEAST ALONG THE COAST OF BRITISH COLUMBIA. THIS FEATURE MAY
SERVE AS A KICKER TO PUSH THE TROF NORTHEAST TOWARDS CENTRAL
CANADA EARLY NEXT WEEK. AS A RESULT...WE MAY SEE THE EFFECTS OF
THE SECONDARY SHORTWAVE MOVE THROUGH MONTANA AND NORTHERN WYOMING
MONDAY. THIS MAY RESULT IN SOME GUSTY WEST WINDS AHEAD OF THE
BOUNDARY ACROSS AREAS MAINLY ALONG AND WEST OF THE LARAMIE RANGE
ON MONDAY. MOISTURE WILL BE QUITE LIMITED AS THIS UPPER LEVEL WAVE
PASSES THROUGH WITH THE BULK OF THE MOISTURE EXPECTED TO BE IN THE
NEBRASKA PANHANDLE. WE MAY SEE A FEW SHOWERS AND THUNDERSTORMS
ALONG AND AHEAD OF THE FRONTAL BOUNDARY IN THE NEBRASKA PANHANDLE
MONDAY AFTERNOON.
TUESDAY-THURSDAY:
SLIGHTLY COOLER AND DRIER CONDITIONS WILL BE ON TAP FOR AREAS
EAST OF THE LARAMIE RANGE ON TUESDAY AS WEAK SURFACE HIGH PRESSURE
BUILDS INTO THE PLAINS. THIS TREND IS EXPECTED TO CONTINUE THROUGH
WEDNESDAY. MEANWHILE...ANOTHER WEAK UPPER LEVEL DISTURBANCE IS
EXPECTED TO MOVE THROUGH MONTANA AND THE NORTHERN PLAINS ON
WEDNESDAY AND WEDNESDAY NIGHT. MOISTURE AGAIN WILL BE QUITE
LIMITED...SO WE ARE NOT EXPECTING MUCH IN THE WAY OF PRECIPITATION.
CONDITIONS MAY TURN SLIGHTLY COOLER ON THURSDAY...BUT TEMPERATURES
SHOULD STILL STAY ON THE WARM SIDE FOR THIS TIME OF YEAR.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 442 PM MDT FRI SEP 4 2015
USED LATEST HRRR GUIDANCE FOR THE 00Z TAFS. SHOWING A BAND OF
SHOWERS AND THUNDERSTORMS MOVING NORTHEAST OUT OF COLORADO THIS
EVENING...IMPACTING KCYS AND AIRPORTS EAST THROUGH 05Z.
SHOWERS/TSTMS ENDING FROM SOUTH TO NORTH AS THE EVENING
PROGRESSES.
&&
.FIRE WEATHER...
ISSUED AT 318 PM MDT FRI SEP 4 2015
MOIST SOUTHWEST FLOW ALOFT WILL BRING ANOTHER ROUND OF SCATTERED
SHOWERS AND WEAK THUNDERSTORMS TO THE AREA THIS AFTERNOON AND
EVENING WITH A NEAR REPEAT FOR SATURDAY. THE ONLY FIRE WEATHER
CONCERN THROUGH SATURDAY EVENING IS THE POSSIBILITY FOR A FEW
LIGHTNING STRIKES THAT COULD START A WILDFIRE BUT OVERALL THIS
IS A MINIMAL CONCERN.
THE MAIN FIRE WEATHER CONCERN IS SUNDAY FOLLOWING THE PASSAGE
OF A COLD FRONT. WESTERLY WINDS WILL DEVELOP SUNDAY WITH FREQUENT
WIND GUSTS OF 30 TO 40 MPH ACROSS THE FORECAST AREA. RELATIVE
HUMIDITY VALUES ARE EXPECTED TO DIP INTO THE TEENS AND 20S.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...FIRE WEATHER WATCH FROM SUNDAY MORNING THROUGH SUNDAY EVENING
FOR WYZ301>303-308.
NE...NONE.
&&
$$
SHORT TERM...SML
LONG TERM...REC
AVIATION...GCC
FIRE WEATHER...SML