Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/05/15
AREA FORECAST DISCUSSION
NWS FLAGSTAFF AZ
352 PM MST THU SEP 3 2015
.SYNOPSIS...SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE OVER
THE NEXT SEVERAL DAYS...WITH THE BEST CHANCES OF STORMS OVER THE
EASTERN HALF OF THE STATE. DRIER CONDITIONS MAY RETURN TO NORTHERN
ARIZONA EARLY NEXT WEEK.
&&
.DISCUSSION...SO FAR TODAY, SHOWER AND THUNDERSTORM ACTIVITY HAS
GENERALLY BEEN CONFINED TO PORTIONS OF NORTHERN GILA, AND
SOUTHERN NAVAJO AND APACHE COUNTIES. THE PRIMARY HAZARD FROM THESE
STORMS HAS BEEN LOCALIZED FLOODING FROM HEAVY RAINFALL.
FOR THE REST OF TODAY AND TONIGHT...SHOWER AND THUNDERSTORM
ACTIVITY IS EXPECTED TO CONTINUE PRIMARILY ALONG AND TO THE NORTH
OF THE EASTERN MOGOLLON RIM AND WHITE MOUNTAINS THIS AFTERNOON.
HI-RES MODEL GUIDANCE STILL INDICATES THAT OUTFLOWS FROM
CONVECTIVE ACTIVITY OVER SOUTHERN ARIZONA MAY TRIGGER NEW SHOWERS
AND THUNDERSTORMS ALONG AND SOUTH OF THE MOGOLLON RIM FROM
FLAGSTAFF EASTWARD - ALTHOUGH THE HRRR HAS BACKED OFF ON THIS
PREDICTION OVER THE LAST COUPLE OF RUNS.
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS IS EXPECTED ON FRIDAY,
WITH THE GREATEST ACTIVITY ROUGHLY EAST OF LINE FROM
PRESCOTT-FLAGSTAFF-PAGE. LOCALIZED FLOODING FROM HEAVY RAINFALL
WILL CONTINUE TO BE THE PRIMARY HAZARD, BUT INCREASING DEEP LAYER
SHEAR MEANS LARGE HAIL CANNOT BE RULED OUT.
SATURDAY ONWARD...AS WE ENTER THE WEEKEND...FLOW WILL TURN WEST-
SOUTHWESTERLY AS LOW PRESSURE SHIFTS ACROSS THE GREAT BASIN. THIS
SHOULD LEAD TO A DOWNTURN IN ACTIVITY FROM LATE SATURDAY INTO
EARLY NEXT WEEK. ECMWF KEEPS MOISTURE MUCH MORE LIMITED THROUGH
THE EXTENDED FORECAST WHILE THE GFS IS MORE FAVORABLE TO RETURNING
STORM CHANCES NEXT WEEK. WILL CONTINUE TO OBSERVE MODEL FORECAST
TRENDS OVER THE COMING DAYS.
&&
.AVIATION...FOR THE 00Z PACKAGE...SCATTERED STORMS WILL CONTINUE
THIS EVENING ACROSS NAVAJO, APACHE, AND GILA COUNTIES. ANOTHER ROUND
OF SCATTERED SHRA/TSRA WILL DEVELOP AFT 18Z FRIDAY PRIMARILY ALONG
AND EAST OF A PRESCOTT-FLAGSTAFF-PAGE LINE. ISOLATED STORMS
POSSIBLE ELSEWHERE. LOCALIZED IFR CONDITIONS POSSIBLE IN MOD/HVY
RAIN ALONG WITH GUSTY STORM OUTFLOWS TO 30 KTS. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...RR
AVIATION...CLM
FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT
WEATHER.GOV/FLAGSTAFF
AREA FORECAST DISCUSSION
NWS TUCSON AZ
950 PM MST WED SEP 2 2015
.SYNOPSIS...THERE IS A GOOD CHANCE OF SHOWERS AND THUNDERSTORMS
THURSDAY AFTERNOON AND EVENING. ISOLATED TO SCATTERED THUNDERSTORMS
WILL THEN PREVAIL FRIDAY INTO EARLY NEXT WEEK. THE BULK OF THIS
ACTIVITY WILL OCCUR FROM TUCSON EAST AND SOUTH WITH LESSER CHANCES
WEST OF TUCSON. EXPECT REDUCED THUNDERSTORM CHANCES BY THE MIDDLE OF
NEXT WEEK.
&&
.DISCUSSION...IR SATELLITE IMAGERY AND SURFACE OBSERVATIONS DEPICTED
PARTLY CLOUDY TO CLOUDY SKIES FROM TUCSON EWD TO THE NEW MEXICO
BORDER AT THIS TIME. MEANWHILE...CLEAR SKIES PREVAILED ACROSS WRN
PIMA COUNTY. THIS FORECAST AREA WAS VOID OF PRECIP ECHOES VALID
0445Z AS PER KEMX WSR-88D. HOWEVER...A THUNDERSTORM COMPLEX
WAS MOVING NEWD ACROSS NERN SONORA MEXICO...AND CLOUD TOPS WERE
COOLING ACROSS FAR SERN SECTIONS AHEAD OF THIS RELATIVELY SMALL MCS.
BASED ON SATELLITE/RADAR TRENS AS WELL AS THE 03/00Z NAM12 AND
SEVERAL HRRR SOLUTIONS...HAVE MAINTAINED A SLIGHT CHANCE OF SHOWERS/
TSTMS ACROSS MUCH OF SE ARIZONA THE REST OF TONIGHT. PRECIP-FREE
CONDITIONS WILL CONTINUE ACROSS WRN PIMA COUNTY.
HOWEVER...HAVE NOTED SOME DIFFERENCES BETWEEN THE HRRR SOLUTIONS AND
THE NAM12 REGARDING PRECIP POTENTIAL INTO EARLY THUR MORNING. THE
HRRR HAS BEEN CONSISTENT WITH DEVELOPING MOSTLY LIGHT RAIN AMOUNTS
ACROSS COCHISE COUNTY LATER TONIGHT...ESSENTIALLY AROUND 10Z...THEN
EXPANDING THE COVERAGE OF SHOWERS/TSTMS NWWD INTO ERN PIMA/SE PINAL
COUNTIES AROUND DAYBREAK THUR.
MEANWHILE...THE NAM12 DEPICTED MEASURABLE RAINFALL TO OCCUR LATER
TONIGHT MAINLY CONFINED TO PORTIONS OF GRAHAM COUNTY AND NERN PIMA
COUNTY. THEREAFTER...THE NAM12 DEPICTED FAIRLY EXTENSIVE COVERAGE OF
LIGHT TO MODERATE RAIN AMOUNTS TO OCCUR ACROSS MUCH OF THE AREA BY
LATE THUR MORNING...THEN HEAVIER AMOUNTS TO OCCUR ESPECIALLY SE OF
TUCSON THUR AFTERNOON.
AT ANY RATE...THE OFFICIAL FORECAST CONTINUES WITH AT LEAST A SLIGHT
CHANCE OF SHOWERS/TSTMS ACROSS MUCH OF THE AREA THUR MORNING...THEN
AT LEAST CHANCE-CATEGORY POPS ACROSS MUCH OF THIS FORECAST AREA THUR
AFTERNOON/EVENING. HIGH TEMPS THUR ARE FORECAST TO AVERAGE ABOUT
5 DEGS F COOLER VERSUS TEMPS ACHIEVED THIS AFTERNOON.
PLEASE REFER TO THE ADDITIONAL SECTIONS FOR FURTHER DETAIL.
&&
.AVIATION...VALID THRU 04/06Z.
ISOLATED -TSRA/-SHRA WILL OCCUR INTO THURSDAY MORNING...WITH THE
BULK OF THIS ACTIVITY SE OF KTUS AND ESPECIALLY IN THE VICINITY OF
THE KDUG TERMINAL. SCATTERED TO NUMEROUS -TSRA/-SHRA WILL THEN OCCUR
ACROSS MUCH OF THE AREA THURSDAY AFTERNOON AND EVENING. MVFR
CONDITIONS AND WIND GUSTS OF 35-45 KTS WILL OCCUR WITH THE STRONGER
TSRA. OTHERWISE...EXPECT LAYERED CLOUDS MOSTLY BETWEEN 8-15K FT AGL
AND SURFACE WIND GENERALLY LESS THAN 10 KTS INTO THURSDAY EVENING.
AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...A GOOD CHANCE OF THUNDERSTORMS WILL PREVAIL
THURSDAY AND THURSDAY EVENING...PARTICULARLY FROM TUCSON EAST AND
SOUTH TO THE NEW MEXICO/INTERNATIONAL BORDERS. ISOLATED TO
SCATTERED THUNDERSTORMS WILL THEN OCCUR FRIDAY INTO EARLY NEXT
WEEK. THE LEAST ACTIVITY WILL OCCUR ACROSS FIRE ZONE 150 WEST
TO NORTHWEST OF TUCSON. BRIEF STRONG...GUSTY AND ERRATIC WINDS WILL
ACCOMPANY THE STRONGER THUNDERSTORMS. A GRADUAL DRYING TREND WILL
LEAD TO LESS THUNDERSTORM ACTIVITY BY NEXT WEDNESDAY. OTHERWISE...
EXPECT TERRAIN DRIVEN WINDS MOSTLY LESS THAN 15 MPH INTO NEXT WEEK.
&&
.PREV DISCUSSION /135 PM MST/...THURSDAY THERE IS ANOTHER IMPULSE ON
ITS WAY TO AFFECT THE AREA ALTHOUGH MODELS INDICATE THAT IT MAY BE A
FEW HOURS LATER THAN TODAYS PUTTING THE FOCUS LATER IN THE DAY AND
OVERNIGHT THURSDAY. AGAIN THE POTENTIAL FOR LOCAL FLOODING AND WET
MICROBURST ACTIVITY. SHOULD BE ENOUGH FLOW ALOFT TO RESET THE
ATMOSPHERE SO WILL MAINTAIN THE RELATIVELY HIGH POPS.
BEYOND THAT WE STILL MAINTAIN A SOUTH TO SW FLOW ACROSS THE AREA
WITH MOISTURE STREAMING NORTH SATURDAY AND SUNDAY ALTHOUGH THE
MOISTURE ISN/T QUITE AS HIGH. COULD/SHOULD ALSO HAVE SOME
DISTURBANCES IN THAT FLOW TO HELP CONVECTION AT TIMES ALTHOUGH TOO
EARLY TO TRY TO CAPTURE AND TIME THOSE. THROUGH OUT THE THURSDAY
THROUGH SUNDAY TIME FRAME...DUE TO CLOUDS...PRECIPITATION AND LOWER
THICKNESS VALUES HIGH TEMPERATURES WILL BE SEVERAL DEGREES BELOW
NORMAL.
THEN BOTH THE GFS (WHICH PICKED THIS WHOLE SCENARIO UP WELL THUS
FAR) AND THE ECMWF INDICATED A MORE SIGNIFICANT DISTURBANCE WILL
ROTATE UP THROUGH HERE WITH A FAIR AMOUNT OF MOISTURE. THE DETAILS
DIFFER...HOWEVER WITH BOTH SHOWING A SIMILAR IDEA THIS FAR OUT IT
NEEDS TO BE NOTED. IF IT WERE TO COME TO PASS IT SHOULD PROVIDE FOR
ANOTHER VERY ACTIVE DAY OF CONVECTION. THEN BEYOND THAT THE TREND
IS TO A MORE WESTERLY FLOW WHICH WOULD SLOWLY DRY OUT THE AIR MASS
WITH TEMPERATURES CLIMBING BACK UP TO NORMAL LEVELS.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
538 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 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 538 PM MDT FRI SEP 4 2015
MOIST SOUTHWEST FLOW WILL KEEP ISOLATED TO SCATTERED SHOWERS
POPPING OVER THE EASTERN GREAT BASIN TO THE ROCKIES OVERNIGHT.
RADAR TRENDS SHOW KTEX...KASE...KEGE HAVE THE BEST POTENTIAL TO BE
IMPACTED BY GUSTY WINDS NEAR THE SHOWERS THROUGH 05/02Z...OTHERWISE
VFR CONTINUES. SOME OF THESE GUSTS WILL EXCEED 35 MPH THROUGH
LATE EVENING. IN GENERAL THINGS QUIET DOWN AFTER MIDNIGHT WITH A
RETURN OF THE SHOWER AND THUNDERSTORM ACTIVITY TOMORROW AFTERNOON.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...JOE/TGR
LONG TERM...TGR
AVIATION...TGJT
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1100 PM MDT WED SEP 2 2015
.UPDATE...
ISSUED AT 707 PM MDT WED SEP 2 2015
UPDATED MAINLY POPS IN THE GRIDS/ZONES TO REFLECT LATEST
RADAR TRENDS AND HI RES GUIDANCE. LOTS OF UPSTREAM CONVECTION
STILL MOVING NORTHWARD THROUGH NRN NM...AND SOME OF THIS SHOULD
MOVE INTO SC AND SE CO THIS EVENING.BEST COVERAGE WILL BE OVER THE
ERN MTS AND SURROUNDING AREAS OVER THE NEXT FEW HOURS. WITHOUT ANY
STRONG FORCING...SHOULD SEE CONVECTION DIMINISH LATER THIS EVE BUT
CANNOT RULE OUT SOME ISOLD ACTIVITY OVER THE LOWER ELEVATIONS.
LATE TONIGHT...WILL START TO SEE THE INFLUENCE OF A SURGE OF
MONSOONAL MOISTURE INTO SW CO...SO HAVE BOOSTED POPS SLIGHTLY
EARLY THU FOR THE CONTDVD. ROSE
&&
.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
NORTHWESTERN 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
DEGREES 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 AFTERNOON AND
EVENING...WITH ISOLATED TO SCATTERED POPS OVER THE MTS AND
ISOLATED ELSEWHERE. LOOK FOR MILD NIGHTS...AND MAX TEMPS EACH
AFTERNOON 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
AFTERNOON 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 AFTERNOON 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 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1045 PM MDT WED SEP 2 2015
MONSOON PATTERN WILL CONTINUE NEXT 24 HOURS. SHOULD SEE INCREASE
IN THUNDERSTORM COVERAGE AND STRENGTH OVER THE MOUNTAINS TOMORROW
ALTHOUGH LITTLE CHANGE IS EXPECTED ACROSS THE PLAINS. GENERALLY
VFR ACROSS FLIGHT AREA BUT MVFR/IFR/LIFR FLIGHT CONDITIONS WILL
BE POSSIBLE IN AREAS OF PRECIPITATION...ESPECIALLY OVER THE
MOUNTAINS...AND ESPECIALLY 18Z-00Z. HEAVY RAIN...FLASH
FLOODING...GUSTY WINDS AND LIGHTNING ARE MAIN STORM
THREATS...ESPECIALLY OVER THE MOUNTAINS.
BEST CHANCE OF THUNDERSTORMS TOMORROW WILL BE AT KALS. FOR
NOW...WILL CARRY VCTS AT KALS 17Z-04Z THURSDAY. SECOND BEST CHANCE
OF A TERMINAL STORM IS AT KCOS. WILL CARRY VCTS THERE 18Z-04Z
THURSDAY. FOR KPUB...CURRENTLY LOOKS LIKE THUNDERSTORMS WILL
REMAIN TOO FAR WEST TO INCLUDE IN TERMINAL FORECAST SO NO MENTION
THERE AT THIS TIME. ALL 3 TAFS WILL BE SUBJECT TO AMENDMENTS TOMORROW
AFTERNOON PENDING CONVECTIVE EVOLUTION.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...ROSE
SHORT TERM...PETERSEN
LONG TERM...MOORE
AVIATION...LW
AREA FORECAST DISCUSSION
NWS NEW YORK NY
331 PM EDT THU SEP 3 2015
.SYNOPSIS...
A COLD FRONT PASSES THROUGH TONIGHT FROM THE NORTH. HIGH PRESSURE
BUILDS DOWN FROM SOUTHEASTERN CANADA ON FRIDAY AND REMAINS IN
CONTROL THROUGH THE MIDDLE OF NEXT WEEK...WITH A COLD FRONT
POSSIBLY APPROACHING LATE IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS OF 19Z...CONVECTION IS WELL NORTH AND WEST OVER THE MOUNTAINS.
PER LATEST HRRR AND RAP RUNS ALONG WITH NARRE-TL DISSIPATION OF
CONVECTION IS FORECAST WITH LOSS OF DAYTIME HEATING. ONLY AREA
THAT COULD GET A STORM THOUGH 8 PM IS ORANGE COUNTY WHERE MUCAPE`S
ARE NEAR 1500 J/KG.
HAVE LIMITED POPS TO ISOLATED OVERNIGHT BASED ON NWP, LIMITED
DYNAMICS (WEAK PVA) AND MODEST AT BEST INSTABILITY.
LOWS ARE A MOS BLEND IN THE MID 60S TO LOWER 70S IN THE NY METRO.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
BIG CHANGE IN THE WEATHER FOR FRI AS NE WIND USHERS IN COOLER AND
DRIER AIR. ALSO EXTENSIVE COULD COVER IS FORECAST. TEMPS COULD
ACTUALLY NOT BREAK 80 IN CENTRAL PARK FOR THE FIRST TIME IN NEARLY
2 MONTHS. HAVE GONE WITH COOLER GFS MOS BASED ON EXPECTATIONS OF
EXTENSIVE CLOUD COVER. MAX TEMPS ARE NEAR 80.
CLEARING FOR FRIDAY NIGHT WITH THE NE FLOW PERSISTING.
RIP CURRENT POTENTIAL INCREASE THROUGH THE DAY AS SEAS BUILD AND
LONG SHORE CURRENT INCREASES ALONG THE SOUTH SHORE OF LONG ISLAND.
HIGH RISK LIKELY PERSISTS INTO SATURDAY.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
GRADUALLY INCREASING DROUGHT AND FIRE WEATHER CONCERNS THROUGH THE
PERIOD.
MODELS IN GOOD AGREEMENT WITH UPPER RIDGING OVER THE REGION THIS
WEEKEND...GRADUALLY FLATTENING THROUGH MIDWEEK. THERE IS ALSO
OVERALL DEPICTION OF A BROAD AND WEAK UPPER LOW OVER THE SE
US...PART OF WHICH MAY SHEAR NE DURING THE WEEK. PREDICTABILITY ON
THE EVOLUTION OF THIS FEATURE IS LOW. OTHERWISE...DECENT AGREEMENT
ON THE APPROACH OF A NORTHERN STREAM SHORTWAVE LATE IN THE
WEEK...BUT STRENGTH AND TIMING IS AGAIN IN QUESTION.
CANADIAN HIGH PRESSURE BUILDS SOUTH OVER AND EAST OF THE REGION
SATURDAY. THIS WILL MAINTAIN A COOL AND DRY CANADIAN MARITIME
AIRMASS OVER THE REGION. ALONG THE COAST...POTENTIAL EXISTS FOR A
HIGH RIP CURRENT RISK SAT DUE TO 5 FT EASTERLY SWELLS/WAVES. HIGHS
SHOULD RUN NEAR SEASONABLE...UPPER 70S/LOWER 80S.
DRY AND VERY WARM TO HOT CONDITIONS ARE EXPECTED EARLY TO MID NEXT
WEEK AS HIGH PRESSURE SINKS SE OF THE REGION AND EVENTUALLY MERGES
WITH BERMUDA HIGH. A STEADY MODERATION IN HEAT AND HUMIDITY IS
LIKELY SUN THROUGH WED...WITH HIGHS INCREASING TO 5 TO 10 DEGREES
ABOVE SEASONABLE THROUGH THE EARLY WEEK PERIOD. GENERALLY UPPER 80S
TO LOWER 90S...WITH HEAT INDICES AT THIS POINT LOOKING JUST NEAR OR
SLIGHTLY HIGHER THAN TEMPS.
THE CAVEAT IN THE FORECAST FOR NEXT WEEK IS THAT WITH THE WEAK UPPER
LOW EXTENDING INTO THE WESTERN ATLANTIC...THERE IS POTENTIAL FOR
SOME TYPE OF SUBTROPICAL TROUGH LIFTING INTO THE MID ATLANTIC REGION
EARLY/MID WEEK. THIS WOULD POSE POTENTIAL FOR INCREASED CLOUD COVER
AND PERHAPS EVEN SOME SHOWERS DURING THE EARLY TO MID WEEK.
POTENTIAL IN THIS OCCURRENCE IS LOW AT THIS POINT.
OTHERWISE...POTENTIAL EXISTS FOR RIDGING TO FLATTEN ENOUGH BY
THURSDAY FOR APPROACH OF A WEAK SHORTWAVE AND ASSOCIATED COLD FRONT
BRINGING A CHANCE FOR SHOWERS AND THUNDERSTORMS. THIS WOULD ALSO
ALLOW FOR A COOLER AIRMASS TO INFILTRATE THE AREA.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
A COLD FRONT MOVE ACROSS THE AREA TONIGHT. HIGH PRESSURE STARTS
TO BUILD INTO THE REGION ON FRIDAY
VFR THROUGH MIDNIGHT. ISOLATED SHOWERS OR THUNDERSTORMS OVERNIGHT.
CONFIDENCE IN OCCURRENCE IS TOO LOW FOR INCLUSION IN TAFS.
MVFR CIGS ARE LIKELY EARLY FRIDAY MORNING WITH CIGS FALLING TO
2-3KFT. THERE MAY BE A FEW ISOLATED LOCATIONS WHICH FALL BELOW
2KFT. A GRADUAL IMPROVEMENT IN CIGS IS THEN LIKELY DURING THE
AFTERNOON.
SEA BREEZES ALONG THE COAST THIS AFTERNOON. WINDS BECOME LIGHT
AND VARIABLE THIS EVENING...BUT BECOME NE BEHIND THE FRONT. WINDS
INCREASE FRIDAY MORNING TO 10-15 KT...WITH GUSTS TO 20 KT.
...NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: AN OCCASIONAL GUST INTO THE TEENS POSSIBLE
LATE THIS AFTERNOON.
KLGA FCSTER COMMENTS: LOW TO MODERATE CONFIDENCE IN OCCURRENCE AND
TIMING OF SEABREEZE.
KEWR FCSTER COMMENTS: LOW TO MODERATE CONFIDENCE IN OCCURRENCE AND
TIMING OF SEABREEZE.
KTEB FCSTER COMMENTS: LOW CONFIDENCE OF SEABREEZE OCCURRING THIS
AFTERNOON.
KHPN FCSTER COMMENTS: LOW CONFIDENCE OF SEABREEZE OCCURRING THIS
AFTERNOON.
KISP FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.
.OUTLOOK FOR 18Z FRIDAY THROUGH TUESDAY...
.FRIDAY AFTERNOON...MVFR CIGS GIVING WAY TO VFR CIGS LATE.
NE-E WINDS G15-20KT POSSIBLE.
.FRIDAY NIGHT...VFR. E-NE WINDS G15-20KT POSSIBLE.
.SATURDAY-TUESDAY...VFR.
&&
.MARINE...
TRANQUIL CONDITIONS THIS EVENING WITH A SOUTHERLY SEA BREEZE.
A COLD FRONT PASSES THROUGH OVERNIGHT BRING IN A NE FLOW THAT
INCREASES THROUGH THE DAY ON FRIDAY. SCA IS ISSUES FOR THE OCEAN
STARTING AT 10 AM...THOUGH THE SCA CONDITION WILL SPREAD FROM EAST
TO WEST BETWEEN LATE MORNING AND EARLY AFTERNOON. POTENTIAL FOR
SMALL CRAFT ADVISORY LEVEL CONDITIONS TO CONTINUE ON THE OCEAN
INTO SATURDAY MORNING...THEN GRADUALLY SUBSIDING BELOW SCA LEVELS
BY SAT NIGHT AS HIGH PRESSURE BUILDS OVERHEAD.
THEREAFTER...SUB SCA CONDS EXPECTED THROUGH EARLY NEXT WEEK IN A WEAK
PRESSURE GRADIENT AS HIGH PRESSURE SINKS SE OF THE REGION.
&&
.FIRE WEATHER...
SEE SPECIAL ISSUANCE OF FIRE WEATHER PLANNING FORECAST RELATED TO
GUSTY WINDS TOMORROW.
FNUS51 KOKX / NYCFWFOKX
&&
.HYDROLOGY...
NO WIDESPREAD SIGNIFICANT RAINFALL IS FORECAST THROUGH THE MIDDLE
OF NEXT WEEK.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM FRIDAY TO 6 AM EDT SATURDAY
FOR ANZ350-353-355.
&&
$$
SYNOPSIS...TONGUE/NV
NEAR TERM...TONGUE
SHORT TERM...TONGUE
LONG TERM...NV
AVIATION...BC
MARINE...TONGUE/NV
FIRE WEATHER...
HYDROLOGY...TONGUE
AREA FORECAST DISCUSSION
NWS ALBANY NY
203 PM EDT THU SEP 3 2015
.SYNOPSIS...
A WEAK COLD FRONT WILL MOVE ACROSS THE REGION THIS
AFTERNOON INTO TONIGHT. THIS WILL BE THE MAIN FOCUS MECHANISM FOR
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS...WITH THE BEST
PROBABILITIES ACROSS THE HIGHER TERRAIN. THEREAFTER...HIGH PRESSURE
BUILDS ACROSS THE REGION FOR THE HOLIDAY WEEKEND WITH MAINLY DRY
CONDITIONS AND ABOVE NORMAL TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 135 PM EDT...THE COLD FRONT CONTINUES TO MOVE SOUTHWARD
ACROSS THE ADIRONDACKS. THE 0-6 KM BULK WIND SHEAR CONTINUES TO
VERY WEAK WITH LESS THAN 20KTS OVER THE NRN TIER OF THE FCST AREA.
THE ISOLD CELLS THAT FORMED ALONG THE RIM OF THE FOOTHILLS OF THE
ADIRONDACKS HAVE EXHIBITED PULSE TYPE CHARACTERISTICS...AS THEY
TAP INTO MODERATE INSTABILITY IN THE 1000-2000 J/KG RANGE BASED ON
THE LATEST SPC MESO-ANALYSIS PAGE. THE STEEPER MID LEVEL LAPSE
RATES ARE WEST OF THE ALY FCST AREA TOO. THE BEST CLOUD TO GROUND
LTG IS WITH THE CELL OVER SRN LEWIS/NRN ONEIDA COUNTIES...WEST OF
THE FCST AREA. EXPECTING MAINLY ISOLD TO PERHAPS SCT SHOWERS AND
THUNDERSTORMS WITH A LOCALLY HEAVY BURST OF RAIN. CAN NOT RULE OUT
A ROGUE SEVERE DUE TO PCPN LOADING INTO THE CELLS...AND CAPE
VALUES OF 1000 J/KG ESPECIALLY NORTH AND WEST OF ALY. PWATS HAVE
RISEN INTO THE 1-1.5" RANGE...SO SOME LOCALLY HEAVY RAINFALL IS
POSSIBLE. IT IS INTERESTING THAT THE LATEST HRRR HAS THE
CONVECTION WEAKEN AS IS MOVES SOUTH OF THE CAPITAL REGION/MOHAWK
VALLEY...AND KEEPS IT ISOLD.
TEMPERATURES WERE ADJUSTED A FEW DEGREES UP INTO THE U80S FROM
THE CAPITAL DISTRICT SOUTH AND EAST DUE TO MORE HEATING...WITH
U80S TO NEAR 90F IN SOME OF THE VALLEYS AREAS...WITH LOWER TO M80S
OVER THE MTNS. FURTHER NORTH EXPECT M70S TO M80S.
TONIGHT RESIDUAL CONVECTION SHOULD DISSIPATE AS SURFACE
ANTICYCLONE BUILDS IN FROM NORTHEAST CANADA. TRENDS IN THE MODEL
SUITE SUGGEST LOW LEVEL MOISTURE FROM THE ENE TRAJECTORIES ALONG
WITH UPSLOPE CONDITIONS INTO THE GREENS...BERKS AND NW CT AND SLOW
MOVEMENT OF THE FRONTAL MOVEMENT SOUTH OF I90 COULD KEEP CLOUDS A
BIT LONGER AND PERHAPS AN ISOLATED SHOWER UNTIL SHORTLY AFTER
MIDNIGHT. MOS VALUES OVERNIGHT ARE VERY CLOSE AND A BLENDED
APPROACH WAS UTILIZED. FOG POTENTIAL IS NOT THAT CLEAR AT THIS
TIME AS WE WATCH THE POTENTIAL FOR STRATUS DEVELOPMENT.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
FRIDAY...STILL SOME QUESTION JUST HOW MUCH LOW LEVEL STRATUS WILL
BE ACROSS THE REGION AS THE GFS IS MORE AGGRESSIVE THAN THE NAM.
HOWEVER...THEY BOTH AGREE THE WEAKENING FRONTAL BOUNDARY MAY GET
HUNG UP ALONG THE I84 CORRIDOR WHERE WE WILL KEEP THE SLIGHT
CHANCE POPS AT THIS TIME ALONG WITH ADDITIONAL CLOUD COVERAGE.
OTHERWISE...BREAKS IN THE CLOUD COVERAGE AND AS H925-850 COOL OFF
FROM THE ENE INTO THE LOWER TEENS...THIS SHOULD YIELD EVEN COOLER
AFTERNOON HIGHS WITH NEAR 80F FOR VALLEY LOCATIONS WITH MAINLY 70S
FOR THE ENTIRE CWFA.
FRI NIGHT...A PLEASANT EVENING IS EXPECTED WITH GRADUAL CLEARING
TO MOSTLY CLEAR SKIES AND CALM WINDS...AS THE SFC HIGH MOVES OVER
NY AND NEW ENGLAND. IDEAL RADIATIONAL COOLING CONDITIONS WILL
OCCUR...AND LOWS WILL BE MAINLY IN THE LOWER TO M50S WITH A FEW
U40S IN THE SRN DACKS. SOME PATCHY OR AREAS OF RADIATIONAL FOG MAY
FORM...AND MAY NEED TO BE ADDED TO THE FCST LATER IN TIME FOR MORE
WIDESPREAD FOG.
SATURDAY...A GOOD DEAL OF SUNSHINE AS TEMPS WILL BE SLIGHTLY
WARMER THAN FRIDAY WITH A MID AND UPPER LEVEL RIDGE BUILDING IN
OVER THE NORTHEAST. A CLOSED ANTICYCLONE MAY SET UP OVER NY AND
NEW ENGLAND LATE IN THE DAY. H925-850 TEMPS REBOUND BACK INTO THE
MID TEENS CELSIUS ALONG WITH INCREASING SUBSIDENCE WITH THE MID
AND UPPER RIDGE...AND THE SFC ANTICYCLONE FOR 80S IN THE VALLEYS
AND 70S FOR THE TERRAIN.
SATURDAY NIGHT...BIG BUBBLE...LITTLE TROUBLE AS THE COMBINATION OF
CLEAR SKIES...CALM WINDS AND LONGER NOCTURNAL PERIOD SHOULD ALLOW
FOR RADIATIONAL FOG TO FORM ONCE AGAIN AND COULD BE EVEN MORE
WIDESPREAD. THIS WILL CONTINUE TO BE MONITORED AND EVALUATED IN
LATER FORECASTS. LOWS MAINLY INTO THE 50S FOR THE REGION.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
THE LONG TERM PORTION OF THE FORECAST WILL FEATURE ABOVE NORMAL
TEMPERATURES AND BELOW NORMAL PRECIPITATION...CONTINUING THE TREND
FROM THE SHORT TERM.
A RIDGE OF HIGH PRESSURE AT ALL LEVELS OF THE ATMOSPHERE WILL
PROVIDE THE DRY AND VERY WARM CONDITIONS THROUGH AT LEAST LABOR DAY.
500 MB HEIGHTS AND 850 MB TEMPERATURES ARE FORECAST TO BE +1 TO +2
STDEV ACCORDING TO THE GEFS WHICH WILL RESULT IN MID LEVEL CAPPING
SUPPRESSING CONVECTION WITH PLENTY OF SUNSHINE. NORMAL HIGH
TEMPERATURES FOR ALBANY BY EARLY NEXT WEEK WILL BE THE MID
70S...HOWEVER WE WILL EXPERIENCE TEMPERATURES IN THE MID TO UPPER
80S...WITH SOME TEMPS POSSIBLY APPROACHING 90 IN PORTIONS OF THE MID
HUDSON VALLEY BY MONDAY. OVERNIGHT LOW TEMPERATURES SHOULD FALL INTO
THE 50S TO LOWER 60S FOR MON AM...THEN MAINLY LOWER/MID 60S FOR MON
NT/TUE AM ALTHOUGH SOME 50S COULD STILL OCCUR IN PORTIONS OF THE
ADIRONDACKS AND EASTERN CATSKILLS...AS WELL AS PORTIONS OF THE
SOUTHERN GREENS AND IN THE BERKSHIRES. HUMIDITY LEVELS SHOULD REMAIN
SOMEWHAT COMFORTABLE THROUGH MONDAY.
THE NEXT CHANCE OF ANY PRECIPITATION ARRIVES ON TUESDAY AS A
WEAKENING FRONTAL BOUNDARY APPROACHES FROM THE NORTH AND WEST.
LATEST MODELS SUGGEST THAT THIS FRONT WEAKENS QUITE A BIT BEFORE
REACHING OUR REGION...AS THE BEST UPPER LEVEL SUPPORT SHEARS WELL N
AND W OF THE REGION. THIS ENERGY SHOULD FLATTEN OUT THE UPPER LEVEL
RIDGE A BIT. WILL ONLY INCLUDE SOME SLIGHT CHANCE TO LOW CHC POPS
FOR THE ADIRONDACKS FOR LATE TUE...AND SLIGHT CHC TUE NT INTO WED
FOR MAINLY THE NORTHERN HALF OF THE REGION. TUESDAY MAX TEMPS SHOULD
STILL REACH THE MID/UPPER 80S FOR MOST AREAS...EXCEPT FOR LOWER 80S
ACROSS HIGHER ELEVATIONS. ONLY SLIGHTLY COOLER CONDITIONS WILL OCCUR
BEHIND THE FRONT...LEAVING WELL ABOVE NORMAL READINGS TO PERSIST.
OVERNIGHT MINS FOR TUE NT/WED AM SHOULD FALL INTO THE LOWER/MID
60S...EXCEPT FOR 50S ACROSS SOME HIGHER ELEVATIONS.
THERE ARE SOME INDICATIONS THAT A STRONGER COLD FRONT MAY APPROACH
THE REGION LATE NEXT WEEK...BUT THIS REMAINS UNCERTAIN. FOR NOW...
ABOVE NORMAL TEMPERATURES CAN BE EXPECTED TO CONTINUE THROUGH THE
NEXT 7-10 DAYS.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
A WEAK COLD FRONT WILL SETTLE SOUTHWARD ACROSS THE TAF SITES THIS
AFTERNOON/EARLY EVENING. ISOLATED SHOWERS/THUNDERSTORMS WILL BE
POSSIBLE WITH OR JUST AHEAD OF THIS FRONT.
OUTSIDE OF ISOLATED SHOWERS/THUNDERSTORMS...VFR CONDITIONS ARE
EXPECTED AT THE KGFL/KPSF/KPOU/KALB TAF SITES THROUGH MUCH OF
TONIGHT. THE ISOLATED/SCATTERED NATURE OF THE CONVECTION THIS
AFTN/EVE MEANS IT IS DIFFICULT TO TIME WHEN ANY SHWR/TSTMS WILL
AFFECT A TAF SITE...SO HAVE ONLY INCLUDED VCSH IN THE TAF
FORECASTS.
LATER TONIGHT AND EARLY FRIDAY MORNING...MVFR/IFR FOG/STRATUS
POSSIBLE AT KGFL/KPSF...BUT NOT AS LIKELY AS THE PAST FEW NIGHTS
SINCE THE REGION WILL BE IN A DRIER AIRMASS AND THERE COULD BE A
LIGHT NORTHEASTERLY FLOW THROUGH THE NIGHT. NO FOG FORECAST FOR
KALB/KPOU. AFTER 14Z FRIDAY...ALL TAF WILL BE VFR ONCE AGAIN.
NORTHERLY WINDS AT 4 TO 8 KTS THIS AFTERNOON...WILL SHIFT TO
NORTHEASTERLY TONIGHT. THE WINDS COULD BECOME LIGHT AND VARIABLE
OR CALM LATE TONIGHT. NORTHEAST TO EAST WINDS ON FRIDAY AT 5 TO 10
KTS.
OUTLOOK...
FRI AFTN-LABOR DAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
OUR RECENT DRY WEATHER...AND MORE EXPECTED IN THE FORECAST...
CONTINUES TO BE MONITORED. HOWEVER...LOW LEVEL MOISTURE REMAINS
ELEVATED AND WITH THE APPROACH OF A WEAK COLD FRONT COULD TOUCH
OFF ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS LATER THIS
MORNING INTO THE AFTERNOON HOURS. MOST OF THIS ACTIVITY SHOULD
DISSIPATE FOR THE REGION TONIGHT BUT A SHOWER OR TWO MAY LINGER
SOUTH OF I90 INTO FRIDAY.
THE RH VALUES WILL FALL TO 45-60 PERCENT THIS AFTERNOON. AN
EXCELLENT RECOVERY IS LIKELY FRIDAY MORNING WITH MAXIMUM RH VALUES
ONCE AGAIN OF 90 TO 100 PERCENT.
THE WINDS WILL BE LIGHT AND VARIABLE IN DIRECTION THIS MORNING.
THE WINDS WILL THEN SHIFT TO THE NORTHWEST TO NORTH AT 5-15 MPH
THIS AFTERNOON...AND THEN WILL BECOME NORTH TO NORTHEAST AT 5 TO
10 MPH BY THIS EVENING.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED THE NEXT 5 DAYS ENDING LABOR DAY.
ISOLATED TO SCATTERED SHOWERS AND OR THUNDERSTORMS WILL BE
POSSIBLE TODAY...AS A BACKDOOR COLD FRONT MOVES SOUTHWARD ACROSS
THE REGION....OTHERWISE IT WILL BE DRY THROUGH THE PERIOD.
RAINFALL AMOUNTS MAY RANGE FROM A TENTH TO QUARTER INCH WITH
LOCALLY HIGHER AMOUNTS FROM ANY THUNDERSTORMS.
ABOVE NORMAL TEMPERATURES WILL CONTINUE THROUGH THE
HOLIDAY WEEKEND...AS HIGH PRESSURE DOMINATES. RIVER FLOWS WILL
REMAIN BELOW NORMAL FOR EARLY SEPTEMBER.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR
WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...BGM/WASULA
NEAR TERM...GJM/BGM/WASULA
SHORT TERM...BGM/WASULA
LONG TERM...KL/JPV
AVIATION...GJM
FIRE WEATHER...BGM/WASULA
HYDROLOGY...BGM/WASULA
AREA FORECAST DISCUSSION
NWS ALBANY NY
135 PM EDT THU SEP 3 2015
.SYNOPSIS...
A WEAK COLD FRONT WILL MOVE ACROSS THE REGION THIS
AFTERNOON INTO TONIGHT. THIS WILL BE THE MAIN FOCUS MECHANISM FOR
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS...WITH THE BEST
PROBABILITIES ACROSS THE HIGHER TERRAIN. THEREAFTER...HIGH PRESSURE
BUILDS ACROSS THE REGION FOR THE HOLIDAY WEEKEND WITH MAINLY DRY
CONDITIONS AND ABOVE NORMAL TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 135 PM EDT...THE COLD FRONT CONTINUES TO MOVE SOUTHWARD
ACROSS THE ADIRONDACKS. THE 0-6 KM BULK WIND SHEAR CONTINUES TO
VERY WEAK WITH LESS THAN 20KTS OVER THE NRN TIER OF THE FCST AREA.
THE ISOLD CELLS THAT FORMED ALONG THE RIM OF THE FOOTHILLS OF THE
ADIRONDACKS HAVE EXHIBITED PULSE TYPE CHARACTERISTICS...AS THEY
TAP INTO MODERATE INSTABILITY IN THE 1000-2000 J/KG RANGE BASED ON
THE LATEST SPC MESO-ANALYSIS PAGE. THE STEEPER MID LEVEL LAPSE
RATES ARE WEST OF THE ALY FCST AREA TOO. THE BEST CLOUD TO GROUND
LTG IS WITH THE CELL OVER SRN LEWIS/NRN ONEIDA COUNTIES...WEST OF
THE FCST AREA. EXPECTING MAINLY ISOLD TO PERHAPS SCT SHOWERS AND
THUNDERSTORMS WITH A LOCALLY HEAVY BURST OF RAIN. CAN NOT RULE OUT
A ROGUE SEVERE DUE TO PCPN LOADING INTO THE CELLS...AND CAPE
VALUES OF 1000 J/KG ESPECIALLY NORTH AND WEST OF ALY. PWATS HAVE
RISEN INTO THE 1-1.5" RANGE...SO SOME LOCALLY HEAVY RAINFALL IS
POSSIBLE. IT IS INTERESTING THAT THE LATEST HRRR HAS THE
CONVECTION WEAKEN AS IS MOVES SOUTH OF THE CAPITAL REGION/MOHAWK
VALLEY...AND KEEPS IT ISOLD.
TEMPERATURES WERE ADJUSTED A FEW DEGREES UP INTO THE U80S FROM
THE CAPITAL DISTRICT SOUTH AND EAST DUE TO MORE HEATING...WITH
U80S TO NEAR 90F IN SOME OF THE VALLEYS AREAS...WITH LOWER TO M80S
OVER THE MTNS. FURTHER NORTH EXPECT M70S TO M80S.
TONIGHT RESIDUAL CONVECTION SHOULD DISSIPATE AS SURFACE
ANTICYCLONE BUILDS IN FROM NORTHEAST CANADA. TRENDS IN THE MODEL
SUITE SUGGEST LOW LEVEL MOISTURE FROM THE ENE TRAJECTORIES ALONG
WITH UPSLOPE CONDITIONS INTO THE GREENS...BERKS AND NW CT AND SLOW
MOVEMENT OF THE FRONTAL MOVEMENT SOUTH OF I90 COULD KEEP CLOUDS A
BIT LONGER AND PERHAPS AN ISOLATED SHOWER UNTIL SHORTLY AFTER
MIDNIGHT. MOS VALUES OVERNIGHT ARE VERY CLOSE AND A BLENDED
APPROACH WAS UTILIZED. FOG POTENTIAL IS NOT THAT CLEAR AT THIS
TIME AS WE WATCH THE POTENTIAL FOR STRATUS DEVELOPMENT.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
FRIDAY...STILL SOME QUESTION JUST HOW MUCH LOW LEVEL STRATUS WILL
BE ACROSS THE REGION AS THE GFS IS MORE AGGRESSIVE THAN THE NAM.
HOWEVER...THEY BOTH AGREE THE WEAKENING FRONTAL BOUNDARY MAY GET
HUNG UP ALONG THE I84 CORRIDOR WHERE WE WILL KEEP THE SLIGHT
CHANCE POPS AT THIS TIME ALONG WITH ADDITIONAL CLOUD COVERAGE.
OTHERWISE...BREAKS IN THE CLOUD COVERAGE AND AS H925-850 COOL OFF
FROM THE ENE INTO THE LOWER TEENS...THIS SHOULD YIELD EVEN COOLER
AFTERNOON HIGHS WITH NEAR 80F FOR VALLEY LOCATIONS WITH MAINLY 70S
FOR THE ENTIRE CWFA.
FRI NIGHT...A PLEASANT EVENING IS EXPECTED WITH GRADUAL CLEARING
TO MOSTLY CLEAR SKIES AND CALM WINDS...AS THE SFC HIGH MOVES OVER
NY AND NEW ENGLAND. IDEAL RADIATIONAL COOLING CONDITIONS WILL
OCCUR...AND LOWS WILL BE MAINLY IN THE LOWER TO M50S WITH A FEW
U40S IN THE SRN DACKS. SOME PATCHY OR AREAS OF RADIATIONAL FOG MAY
FORM...AND MAY NEED TO BE ADDED TO THE FCST LATER IN TIME FOR MORE
WIDESPREAD FOG.
SATURDAY...A GOOD DEAL OF SUNSHINE AS TEMPS WILL BE SLIGHTLY
WARMER THAN FRIDAY WITH A MID AND UPPER LEVEL RIDGE BUILDING IN
OVER THE NORTHEAST. A CLOSED ANTICYCLONE MAY SET UP OVER NY AND
NEW ENGLAND LATE IN THE DAY. H925-850 TEMPS REBOUND BACK INTO THE
MID TEENS CELSIUS ALONG WITH INCREASING SUBSIDENCE WITH THE MID
AND UPPER RIDGE...AND THE SFC ANTICYCLONE FOR 80S IN THE VALLEYS
AND 70S FOR THE TERRAIN.
SATURDAY NIGHT...BIG BUBBLE...LITTLE TROUBLE AS THE COMBINATION OF
CLEAR SKIES...CALM WINDS AND LONGER NOCTURNAL PERIOD SHOULD ALLOW
FOR RADIATIONAL FOG TO FORM ONCE AGAIN AND COULD BE EVEN MORE
WIDESPREAD. THIS WILL CONTINUE TO BE MONITORED AND EVALUATED IN
LATER FORECASTS. LOWS MAINLY INTO THE 50S FOR THE REGION.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
THE LONG TERM PORTION OF THE FORECAST WILL FEATURE ABOVE NORMAL
TEMPERATURES AND BELOW NORMAL PRECIPITATION...CONTINUING THE TREND
FROM THE SHORT TERM.
A RIDGE OF HIGH PRESSURE AT ALL LEVELS OF THE ATMOSPHERE WILL
PROVIDE THE DRY AND VERY WARM CONDITIONS THROUGH AT LEAST LABOR DAY.
500 MB HEIGHTS AND 850 MB TEMPERATURES ARE FORECAST TO BE +1 TO +2
STDEV ACCORDING TO THE GEFS WHICH WILL RESULT IN MID LEVEL CAPPING
SUPPRESSING CONVECTION WITH PLENTY OF SUNSHINE. NORMAL HIGH
TEMPERATURES FOR ALBANY BY EARLY NEXT WEEK WILL BE THE MID
70S...HOWEVER WE WILL EXPERIENCE TEMPERATURES IN THE MID TO UPPER
80S...WITH SOME TEMPS POSSIBLY APPROACHING 90 IN PORTIONS OF THE MID
HUDSON VALLEY BY MONDAY. OVERNIGHT LOW TEMPERATURES SHOULD FALL INTO
THE 50S TO LOWER 60S FOR MON AM...THEN MAINLY LOWER/MID 60S FOR MON
NT/TUE AM ALTHOUGH SOME 50S COULD STILL OCCUR IN PORTIONS OF THE
ADIRONDACKS AND EASTERN CATSKILLS...AS WELL AS PORTIONS OF THE
SOUTHERN GREENS AND IN THE BERKSHIRES. HUMIDITY LEVELS SHOULD REMAIN
SOMEWHAT COMFORTABLE THROUGH MONDAY.
THE NEXT CHANCE OF ANY PRECIPITATION ARRIVES ON TUESDAY AS A
WEAKENING FRONTAL BOUNDARY APPROACHES FROM THE NORTH AND WEST.
LATEST MODELS SUGGEST THAT THIS FRONT WEAKENS QUITE A BIT BEFORE
REACHING OUR REGION...AS THE BEST UPPER LEVEL SUPPORT SHEARS WELL N
AND W OF THE REGION. THIS ENERGY SHOULD FLATTEN OUT THE UPPER LEVEL
RIDGE A BIT. WILL ONLY INCLUDE SOME SLIGHT CHANCE TO LOW CHC POPS
FOR THE ADIRONDACKS FOR LATE TUE...AND SLIGHT CHC TUE NT INTO WED
FOR MAINLY THE NORTHERN HALF OF THE REGION. TUESDAY MAX TEMPS SHOULD
STILL REACH THE MID/UPPER 80S FOR MOST AREAS...EXCEPT FOR LOWER 80S
ACROSS HIGHER ELEVATIONS. ONLY SLIGHTLY COOLER CONDITIONS WILL OCCUR
BEHIND THE FRONT...LEAVING WELL ABOVE NORMAL READINGS TO PERSIST.
OVERNIGHT MINS FOR TUE NT/WED AM SHOULD FALL INTO THE LOWER/MID
60S...EXCEPT FOR 50S ACROSS SOME HIGHER ELEVATIONS.
THERE ARE SOME INDICATIONS THAT A STRONGER COLD FRONT MAY APPROACH
THE REGION LATE NEXT WEEK...BUT THIS REMAINS UNCERTAIN. FOR NOW...
ABOVE NORMAL TEMPERATURES CAN BE EXPECTED TO CONTINUE THROUGH THE
NEXT 7-10 DAYS.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
A WEAK COLD FRONT WILL SETTLE SOUTHWARD ACROSS THE TAF SITES THIS
AFTERNOON/EARLY EVENING. ISOLATED SHOWERS/THUNDERSTORMS WILL BE
POSSIBLE WITH OR JUST AHEAD OF THIS FRONT.
AREAS OF LOW CLOUDS/FOG SHOULD DISSIPATE AT KGFL AND KPSF BETWEEN
12Z-14Z/THU. THEREAFTER...VFR CONDITIONS ARE EXPECTED...OUTSIDE
OF ISOLATED SHOWERS/THUNDERSTORMS WHICH SHOULD DEVELOP BETWEEN
18Z- 22Z/THU. MOST OF THE CONVECTION IS EXPECTED TO REMAIN WEST
AND EAST OF THE TAF SITES...BUT CAN NOT RULE OUT A COUPLE
IMPACTING THE TAF SITES LATER THIS AFTERNOON. BRIEF PERIODS OF
MVFR/IFR VSBYS COULD OCCUR WITHIN THE CORES OF ANY
SHOWERS/THUNDERSTORMS.
CONVECTION SHOULD DECREASE AFTER 00Z/FRI...WITH MAINLY VFR
CONDITIONS CONTINUING THROUGH 06Z/FRI.
SOME LOW CLOUDS MAY DEVELOP AND/OR SPREAD WESTWARD BETWEEN 09Z-
12Z/FRI...ESP AT KPSF AND KPOU. GENERALLY MVFR CIGS WILL BE
POSSIBLE...ALTHOUGH KPSF COULD APPROACH IFR CIGS.
LIGHT/VARIABLE WINDS SHOULD PERSIST THROUGH 13Z/THU...THEN TREND
INTO THE NORTH TO NORTHWEST AT 5-10 KT THIS AFTERNOON. WINDS WILL
THEN SHIFT INTO THE N TO NE BETWEEN 01Z-04Z/FRI IN THE WAKE OF THE
COLD FRONT...AT 5-10 KT...ALTHOUGH COULD BRIEFLY GUST INTO THE
10-20 KT RANGE...ESP AT KGFL DUE TO CHANNELING DOWN THE UPPER
HUDSON/CHAMPLAIN VALLEY AND LAKE GEORGE.
OUTLOOK...
THU NT-LABOR DAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
OUR RECENT DRY WEATHER...AND MORE EXPECTED IN THE
FORECAST...CONTINUES TO BE MONITORED. HOWEVER...LOW LEVEL MOISTURE
REMAINS ELEVATED AND WITH THE APPROACH OF A WEAK COLD FRONT COULD
TOUCH OFF ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS LATER
THIS MORNING INTO THE AFTERNOON HOURS. MOST OF THIS ACTIVITY
SHOULD DISSIPATE FOR THE REGION TONIGHT BUT A SHOWER OR TWO MAY
LINGER SOUTH OF I90 INTO FRIDAY.
THE RH VALUES WILL FALL TO 45-60 PERCENT THIS AFTERNOON. AN
EXCELLENT RECOVERY IS LIKELY FRIDAY MORNING WITH MAXIMUM RH VALUES
ONCE AGAIN OF 90 TO 100 PERCENT.
THE WINDS WILL BE LIGHT AND VARIABLE IN DIRECTION THIS MORNING.
THE WINDS WILL THEN SHIFT TO THE NORTHWEST TO NORTH AT 5-15 MPH
THIS AFTERNOON...AND THEN WILL BECOME NORTH TO NORTHEAST AT 5 TO
10 MPH BY THIS EVENING.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED THE NEXT 5 DAYS ENDING LABOR DAY.
ISOLATED TO SCATTERED SHOWERS AND OR THUNDERSTORMS WILL BE
POSSIBLE TODAY...AS A BACKDOOR COLD FRONT MOVES SOUTHWARD ACROSS
THE REGION....OTHERWISE IT WILL BE DRY THROUGH THE PERIOD.
RAINFALL AMOUNTS MAY RANGE FROM A TENTH TO QUARTER INCH WITH
LOCALLY HIGHER AMOUNTS FROM ANY THUNDERSTORMS.
ABOVE NORMAL TEMPERATURES WILL CONTINUE THROUGH THE
HOLIDAY WEEKEND...AS HIGH PRESSURE DOMINATES. RIVER FLOWS WILL
REMAIN BELOW NORMAL FOR EARLY SEPTEMBER.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR
WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...BGM/WASULA
NEAR TERM...GJM/BGM/WASULA
SHORT TERM...BGM/WASULA
LONG TERM...KL/JPV
AVIATION...KL
FIRE WEATHER...BGM/WASULA
HYDROLOGY...BGM/WASULA
AREA FORECAST DISCUSSION
NWS ALBANY NY
654 AM EDT THU SEP 3 2015
.SYNOPSIS...
A WEAK COLD FRONT WILL TRACK ACROSS THE REGION TODAY. THIS WILL BE
THE MAIN FOCUS MECHANISM FOR ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS TODAY...WITH THE BEST PROBABILITIES ACROSS THE
TERRAIN. THEREAFTER...HIGH PRESSURE BUILDS ACROSS THE REGION FOR
THE HOLIDAY WEEKEND WITH MAINLY DRY CONDITIONS AND ABOVE
SEASONABLE TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 645 AM EDT...SATELLITE IMAGERY CONTINUES TO SHOW SCT-BKN
CI/CS WITH SOME PATCHY FOG PER METARS AND EARLY MORNING SUNRISE
WEB CAMS. 06Z GUIDANCE REMAINS SOMEWHAT CONSISTENT WITH THE
PASSAGE OF THE FRONTAL BOUNDARY/S/ YET COVERAGE REMAINS IN
QUESTION. HRRR REMAINS LESS THAN IDEAL YET THE MAV MOS POPS CAME
IN HIGHER. FOR NOW...NO CHANGES TO THE CURRENT FORECAST WITH THE
HIGHER VALUES ACROSS THE TERRAIN. OTHERWISE...MINOR TWEAKS PER
OBSERVATIONS AND SATELLITE ANALYSIS.
PREV DISC...PER THE SURFACE ANALYSIS A WEAK PRE FRONTAL TROUGH
AXIS WAS DRAPED ALONG THE ST LAWRENCE RIVER VALLEY WITH A SLIGHTLY
STRONGER FRONT /COLD FRONT/ ADVANCING SOUTHWARD ACROSS LOWER
ONTARIO/QUEBEC. TRENDS IN THE IR SATELLITE IMAGERY CONTINUE ALONG
THE PREVIOUS ESTF WITH WARMING CLOUD TOPS WHICH COINCIDES WITH THE
WEAKENING SHOWER TREND ACROSS THE NORTHERN DACKS AND CHAMPLAIN
VALLEY. OTHERWISE...A THIN SCT-BKN CI/CS CANOPY WAS ACROSS MOST OF
THE REGION AND WHERE ENOUGH BREAKS HAVE OCCURRED THIS HAS ALLOWED
FOR FOG FORMATION TO COMMENCE PER A FEW METARS AND REGIONAL WEB
CAMS. AS SUNRISE APPROACHES...EXPECT THE FOG TO LIFT AND DISSIPATE
AS THE CANOPY OF HIGH CLOUDS CONTINUES TO THICKEN. LATER THIS
MORNING AND INTO THE AFTERNOON...THE COMBINATION OF RELATIVELY
HIGH LOW LEVEL MOISTURE AND THE APPROACH OF THE WEAK COLD FRONT
WILL ALLOW FOR LOW LEVEL CONVERGENCE TO INCREASE AND FOR SOME
CONVECTION TO DEVELOP. LATEST NCEP MODEL SUITE OFFER QUITE A
DIFFERENT APPROACH TO THE AMOUNT OF INSTABILITY ACROSS THE REGION
WITH THE NAM REMAINING THE HIGHEST WITH SBCAPES CLIMBING IN EXCESS
OF 2K J/KG. THE GFS IS ABOUT HALF AS MUCH WHICH IS IN CLOSER
AGREEMENT WITH THE HOURLY MESOSCALE UPDATES FROM THE RAP13/HRRR.
THIS IS LIKELY THE CULPRIT OF THE FORECAST SFC DEWPOINTS AS
UPSTREAM VALUES WERE CURRENTLY IN THE MID 60S AS OPPOSED TO THE
NAM WITH VALUES CLOSE TO 70F. AS FOR LAPSE RATES...MODEST VALUES
SEEN IN THE BUFR PROFILES WITH AN AVERAGE 6.5-7.0 C/KM WITHIN THE
H850-500 LAYER. YET THE WIND SHEAR IS LESS THAN IDEAL FOR
ORGANIZED CONVECTION WITH VALUES 20KTS OR LESS. PER SPC
COORDINATION...GENERAL THUNDERSTORM THREAT AND PER THOSE
SOUNDINGS...COULD NOT RULE OUT 1-2 EVENTS ACROSS THE REGION AS THE
COMBINATION OF INVERTED-V TYPE SOUNDINGS AND PRECIP LOADING
CONVECTION COULD RESULT IN AN ISOLATED DOWNBURST.
TEMPERATURES REMAIN ABOVE NORMAL ONCE AGAIN BUT SLIGHTLY COOLER
THAN WEDNESDAYS HIGHS DUE TO THE AFOREMENTIONED CLOUD COVERAGE
AND THE CHANCE FOR PRECIP WITH MAINLY MID 80S FOR VALLEY LOCATIONS
AND 70S FOR THE TERRAIN.
TONIGHT RESIDUAL CONVECTION SHOULD DISSIPATE AS SURFACE
ANTICYCLONE BUILDS IN FROM NORTHEAST CANADA. TRENDS IN THE MODEL
SUITE SUGGEST LOW LEVEL MOISTURE FROM THE ENE TRAJECTORIES ALONG
WITH UPSLOPE CONDITIONS INTO THE GREENS...BERKS AND NW CT AND SLOW
MOVEMENT OF THE FRONTAL MOVEMENT SOUTH OF I90 COULD KEEP CLOUDS A
BIT LONGER AND PERHAPS AN ISOLATED SHOWER. MOS VALUES OVERNIGHT
ARE VERY CLOSE AND A BLENDED APPROACH WAS UTILIZED. FOG POTENTIAL
IS NOT THAT CLEAR AT THIS TIME AS WE WATCH THE POTENTIAL FOR
STRATUS DEVELOPMENT.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
FRIDAY...STILL SOME QUESTION JUST HOW MUCH LOW LEVEL STRATUS WILL
BE ACROSS THE REGION AS THE GFS IS MORE AGGRESSIVE THAN THE NAM.
HOWEVER...THEY BOTH AGREE THE WEAKENING FRONTAL BOUNDARY MAY GET
HUNG UP ALONG THE I84 CORRIDOR WHERE WE WILL KEEP THE SLIGHT
CHANCE POPS AT THIS TIME ALONG WITH ADDITIONAL CLOUD COVERAGE.
OTHERWISE...BREAKS IN THE CLOUD COVERAGE AND AS H925-850 COOL OFF
FROM THE ENE INTO THE LOWER TEENS...THIS SHOULD YIELD EVEN COOLER
AFTERNOON HIGHS WITH NEAR 80F FOR VALLEY LOCATIONS WITH MAINLY 70S
FOR THE ENTIRE CWFA.
FRI NIGHT...A PLEASANT EVENING IS EXPECTED WITH GRADUAL CLEARING
TO MOSTLY CLEAR SKIES AND CALM WINDS...AS THE SFC HIGH MOVES OVER
NY AND NEW ENGLAND. IDEAL RADIATIONAL COOLING CONDITIONS WILL
OCCUR...AND LOWS WILL BE MAINLY IN THE LOWER TO M50S WITH A FEW
U40S IN THE SRN DACKS. SOME PATCHY OR AREAS OF RADIATIONAL FOG MAY
FORM...AND MAY NEED TO BE ADDED TO THE FCST LATER IN TIME FOR MORE
WIDESPREAD FOG.
SATURDAY...A GOOD DEAL OF SUNSHINE AS TEMPS WILL BE SLIGHTLY
WARMER THAN FRIDAY WITH A MID AND UPPER LEVEL RIDGE BUILDING IN
OVER THE NORTHEAST. A CLOSED ANTICYCLONE MAY SET UP OVER NY AND
NEW ENGLAND LATE IN THE DAY. H925-850 TEMPS REBOUND BACK INTO THE
MID TEENS CELSIUS ALONG WITH INCREASING SUBSIDENCE WITH THE MID
AND UPPER RIDGE...AND THE SFC ANTICYCLONE FOR 80S IN THE VALLEYS
AND 70S FOR THE TERRAIN.
SATURDAY NIGHT...BIG BUBBLE...LITTLE TROUBLE AS THE COMBINATION OF
CLEAR SKIES...CALM WINDS AND LONGER NOCTURNAL PERIOD SHOULD ALLOW
FOR RADIATIONAL FOG TO FORM ONCE AGAIN AND COULD BE EVEN MORE
WIDESPREAD. THIS WILL CONTINUE TO BE MONITORED AND EVALUATED IN
LATER FORECASTS. LOWS MAINLY INTO THE 50S FOR THE REGION.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
THE LONG TERM PORTION OF THE FORECAST WILL FEATURE ABOVE NORMAL
TEMPERATURES AND BELOW NORMAL PRECIPITATION...CONTINUING THE TREND
FROM THE SHORT TERM.
A RIDGE OF HIGH PRESSURE AT ALL LEVELS OF THE ATMOSPHERE WILL
PROVIDE THE DRY AND VERY WARM CONDITIONS THROUGH AT LEAST LABOR DAY.
500 MB HEIGHTS AND 850 MB TEMPERATURES ARE FORECAST TO BE +1 TO +2
STDEV ACCORDING TO THE GEFS WHICH WILL RESULT IN MID LEVEL CAPPING
SUPPRESSING CONVECTION WITH PLENTY OF SUNSHINE. NORMAL HIGH
TEMPERATURES FOR ALBANY BY EARLY NEXT WEEK WILL BE THE MID
70S...HOWEVER WE WILL EXPERIENCE TEMPERATURES IN THE MID TO UPPER
80S...WITH SOME TEMPS POSSIBLY APPROACHING 90 IN PORTIONS OF THE MID
HUDSON VALLEY BY MONDAY. OVERNIGHT LOW TEMPERATURES SHOULD FALL INTO
THE 50S TO LOWER 60S FOR MON AM...THEN MAINLY LOWER/MID 60S FOR MON
NT/TUE AM ALTHOUGH SOME 50S COULD STILL OCCUR IN PORTIONS OF THE
ADIRONDACKS AND EASTERN CATSKILLS...AS WELL AS PORTIONS OF THE
SOUTHERN GREENS AND IN THE BERKSHIRES. HUMIDITY LEVELS SHOULD REMAIN
SOMEWHAT COMFORTABLE THROUGH MONDAY.
THE NEXT CHANCE OF ANY PRECIPITATION ARRIVES ON TUESDAY AS A
WEAKENING FRONTAL BOUNDARY APPROACHES FROM THE NORTH AND WEST.
LATEST MODELS SUGGEST THAT THIS FRONT WEAKENS QUITE A BIT BEFORE
REACHING OUR REGION...AS THE BEST UPPER LEVEL SUPPORT SHEARS WELL N
AND W OF THE REGION. THIS ENERGY SHOULD FLATTEN OUT THE UPPER LEVEL
RIDGE A BIT. WILL ONLY INCLUDE SOME SLIGHT CHANCE TO LOW CHC POPS
FOR THE ADIRONDACKS FOR LATE TUE...AND SLIGHT CHC TUE NT INTO WED
FOR MAINLY THE NORTHERN HALF OF THE REGION. TUESDAY MAX TEMPS SHOULD
STILL REACH THE MID/UPPER 80S FOR MOST AREAS...EXCEPT FOR LOWER 80S
ACROSS HIGHER ELEVATIONS. ONLY SLIGHTLY COOLER CONDITIONS WILL OCCUR
BEHIND THE FRONT...LEAVING WELL ABOVE NORMAL READINGS TO PERSIST.
OVERNIGHT MINS FOR TUE NT/WED AM SHOULD FALL INTO THE LOWER/MID
60S...EXCEPT FOR 50S ACROSS SOME HIGHER ELEVATIONS.
THERE ARE SOME INDICATIONS THAT A STRONGER COLD FRONT MAY APPROACH
THE REGION LATE NEXT WEEK...BUT THIS REMAINS UNCERTAIN. FOR NOW...
ABOVE NORMAL TEMPERATURES CAN BE EXPECTED TO CONTINUE THROUGH THE
NEXT 7-10 DAYS.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
A WEAK COLD FRONT WILL SETTLE SOUTHWARD ACROSS THE TAF SITES THIS
AFTERNOON/EARLY EVENING. ISOLATED SHOWERS/THUNDERSTORMS WILL BE
POSSIBLE WITH OR JUST AHEAD OF THIS FRONT.
AREAS OF LOW CLOUDS/FOG SHOULD DISSIPATE AT KGFL AND KPSF BETWEEN
12Z-14Z/THU. THEREAFTER...VFR CONDITIONS ARE EXPECTED...OUTSIDE
OF ISOLATED SHOWERS/THUNDERSTORMS WHICH SHOULD DEVELOP BETWEEN
18Z- 22Z/THU. MOST OF THE CONVECTION IS EXPECTED TO REMAIN WEST
AND EAST OF THE TAF SITES...BUT CAN NOT RULE OUT A COUPLE
IMPACTING THE TAF SITES LATER THIS AFTERNOON. BRIEF PERIODS OF
MVFR/IFR VSBYS COULD OCCUR WITHIN THE CORES OF ANY
SHOWERS/THUNDERSTORMS.
CONVECTION SHOULD DECREASE AFTER 00Z/FRI...WITH MAINLY VFR
CONDITIONS CONTINUING THROUGH 06Z/FRI.
SOME LOW CLOUDS MAY DEVELOP AND/OR SPREAD WESTWARD BETWEEN 09Z-
12Z/FRI...ESP AT KPSF AND KPOU. GENERALLY MVFR CIGS WILL BE
POSSIBLE...ALTHOUGH KPSF COULD APPROACH IFR CIGS.
LIGHT/VARIABLE WINDS SHOULD PERSIST THROUGH 13Z/THU...THEN TREND
INTO THE NORTH TO NORTHWEST AT 5-10 KT THIS AFTERNOON. WINDS WILL
THEN SHIFT INTO THE N TO NE BETWEEN 01Z-04Z/FRI IN THE WAKE OF THE
COLD FRONT...AT 5-10 KT...ALTHOUGH COULD BRIEFLY GUST INTO THE
10-20 KT RANGE...ESP AT KGFL DUE TO CHANNELING DOWN THE UPPER
HUDSON/CHAMPLAIN VALLEY AND LAKE GEORGE.
OUTLOOK...
THU NT-LABOR DAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
OUR RECENT DRY WEATHER...AND MORE EXPECTED IN THE
FORECAST...CONTINUES TO BE MONITORED. HOWEVER...LOW LEVEL MOISTURE
REMAINS ELEVATED AND WITH THE APPROACH OF A WEAK COLD FRONT COULD
TOUCH OFF ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS LATER
THIS MORNING INTO THE AFTERNOON HOURS. MOST OF THIS ACTIVITY
SHOULD DISSIPATE FOR THE REGION TONIGHT BUT A SHOWER OR TWO MAY
LINGER SOUTH OF I90 INTO FRIDAY.
THE RH VALUES WILL FALL TO 45-60 PERCENT THIS AFTERNOON. AN
EXCELLENT RECOVERY IS LIKELY FRIDAY MORNING WITH MAXIMUM RH VALUES
ONCE AGAIN OF 90 TO 100 PERCENT.
THE WINDS WILL BE LIGHT AND VARIABLE IN DIRECTION THIS MORNING.
THE WINDS WILL THEN SHIFT TO THE NORTHWEST TO NORTH AT 5-15 MPH
THIS AFTERNOON...AND THEN WILL BECOME NORTH TO NORTHEAST AT 5 TO
10 MPH BY THIS EVENING.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED THE NEXT 5 DAYS ENDING LABOR DAY.
ISOLATED TO SCATTERED SHOWERS AND OR THUNDERSTORMS WILL BE
POSSIBLE TODAY...AS A BACKDOOR COLD FRONT MOVES SOUTHWARD ACROSS
THE REGION....OTHERWISE IT WILL BE DRY THROUGH THE PERIOD.
RAINFALL AMOUNTS MAY RANGE FROM A TENTH TO QUARTER INCH WITH
LOCALLY HIGHER AMOUNTS FROM ANY THUNDERSTORMS.
ABOVE NORMAL TEMPERATURES WILL CONTINUE THROUGH THE
HOLIDAY WEEKEND...AS HIGH PRESSURE DOMINATES. RIVER FLOWS WILL
REMAIN BELOW NORMAL FOR EARLY SEPTEMBER.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR
WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...BGM
NEAR TERM...BGM
SHORT TERM...BGM/WASULA
LONG TERM...KL/JPV
AVIATION...KL
FIRE WEATHER...BGM/WASULA
HYDROLOGY...BGM/WASULA
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
913 AM EDT THU SEP 3 2015
.UPDATE...SFC DATA SHOWS WEAK LOW PRES NEAR THE SE GA COAST WITH
TROUGHING EXTENDING SW INTO THE FL BIG BEND AND INTO THE NE GULF
OF MEXICO. UPPER LEVEL FORCING NOTED NEAR THE GA COAST WITH VORT
MAX IN NW TO W FLOW...WITH WEAK MID LEVEL RIDGE OVER SW GA IN THE
WAKE OF THIS FEATURE. ANOTHER SHORTWAVE IN WATER VAPOR AND RUC
ANALYSIS THAT IS PRETTY WELL DEFINED WAS OVER ERN/SERN AL MOVING
EWD THAT WILL LIKELY AFFECT OUR WX LATER TODAY.
CURRENTLY AREAS OF LOW CLOUDS ARE IN SE GA WITH SOME PATCHY FOG
THIS IS BEGINNING TO LIFT. CONVECTION ASSOCD WITH REMNANT LOW ARE
OFF THE SE GA COAST AND WILL CONTINUE TO PUSH OUT TO SEA FURTHER.
PRIOR FCST OF ISOLD TO SCT SHOWERS AND ISOLD STORMS LOOKS GOOD
THOUGH WILL TWEAK THEM UP SLIGHTLY TO BASED ON HRRR MODEL RUNS
AND 12Z SOUNDING SHOWING PWAT 2.15 INCHES AND LI OF -7. THINK MOST
IF NOT ALL RAIN CHANCES WILL BE IN THE AFTN HOURS WITH SUBSIDENCE
ON THE BACK SIDE OF LOW/VORT MAX OFFSHORE TO LIMIT CONVECTIVE
POTENTIAL UNTIL DAYTIME HEATING LEADS TO INSTABILITY. SHORTWAVE
COMING INTO OUR LATE TODAY AND TONIGHT MAY INCREASE OUR RAIN
CHANCES AROUND THE 4 PM TO 10 PM TIME FRAME AND WILL BE MONITORED
DURING THE DAY.
&&
.AVIATION...LIFR TO IFR CIGS THIS MORNING ARE MAINLY LIMITED AT
THIS TIME TO JAX...SSI AND CRG WITH MVFR CIGS BY 15Z/16Z. REST OF
TAFS VFR AT THIS TIME. A FEW SHOWERS AND STORMS MAY IMPACT
TERMINALS THIS AFTN BUT LOW PROBABILITIES SUGGEST KEEPING VCTS AT
THIS TIME. OVERALL LOWER CHANCES OF SHOWERS AND STORMS THAN PRIOR
DAYS.
&&
.MARINE...
WEST TO NORTHWEST FLOW NEAR 10 TO OCNL 15 KT THIS MORNING WILL
DECREASE THIS AFTN. SEAS 2-3 FT. SCATTERED SHOWERS AND STORMS
POSSIBLE THIS AFTN ACROSS THE REGIONAL ATLANTIC WATERS. MINOR
TWEAKS IN THE UPDATED CWF.
RIP CURRENTS: LOW SEAS AND WEAK WINDS WILL ALLOW FOR RISK
THROUGH EARLY FRIDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 91 73 94 73 / 30 20 30 20
SSI 86 76 89 76 / 30 20 30 30
JAX 89 75 92 73 / 30 20 40 30
SGJ 91 75 89 75 / 30 20 40 30
GNV 92 73 92 72 / 30 30 50 40
OCF 92 74 91 73 / 40 30 50 40
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...NONE.
&&
$$
SHASHY/WALSH
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1004 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/JASPER COUNTIES OF INDIANA...WITH THE HIGHER
CONCERN EAST INTO CENTRAL INDIANA.
LIKE YESTERDAY...THE LOSS OF DAYTIME HEATING...WE SHOULD SEE
ACTIVITY DIMINISH QUICKLY. THE UPPER LOW LINGERS IN THE REGION
OVERNIGHT. ANOTHER WEAK WAVE WILL ATTEMPT TO MOVE INTO THE UPPER
LEVEL RIDGE THAT WILL BUILD IN FROM THE WEST OVERNIGHT. MANY
GUIDANCE MEMBERS SUGGEST THAT THIS COUPLED WITH SOME RAMPING UP OF
ISENTROPIC LIFT AHEAD OF THIS FEATURE MAY TRIGGER SOME ISOLATED
SHOWERS OR THUNDERSTORMS LATE TONIGHT INTO EARLY SATURDAY. HAVE
MOVED TOWARD THE DRIER NAM SOLUTION AT THIS POINT IN TIME WHICH IS
REFLECTED IN THE EXPERIMENTAL HRRR AND HI-RES NMM/ARW AS WE DO NOT
FEELING FORCING IS STRONG ENOUGH TO TAP INTO ANY ELEVATED
INSTABILITY BUT WILL BE A PERIOD TO WATCH.
THE UPPER RIDGE IS OVER WESTERN ILLINOIS...WITH THE UPPER LOW
INCHING EASTWARD. LOW LEVEL SOUTHWESTERLIES SHOULD ALLOW WARMING ALL
THE WAY TO THE LAKEFRONT WITH 90S INLAND AND UPPER 80S AT THE LAKE.
A WEAKENING OF THE PRESSURE GRADIENT NEAR THE LAKE WOULD SUPPORT A
SE WIND SHIFT NEAR THE LAKE LATER IN THE DAY TO SUPPORT SOME
COOLING. HEAT INDICES WILL GET INTO THE MID TO UPPER 90S IN MANY
SPOTS. HAVE HELD ONTO THE SLIGHT CHANCE POPS FOR TOMORROW
AFTERNOON GIVEN THE MOIST/UNSTABLE ENVIRONMENT...BUT AT THIS POINT
MOST AREAS LOOK TO REMAIN DRY AS THE MAIN TRIGGER IS LACKING.
KMD
&&
.LONG TERM...
SUNDAY THROUGH FRIDAY...
300 PM...MULTIPLE FORECAST CONCERNS INCLUDING HIGH TEMPS SUNDAY
AND MONDAY...PRECIP CHANCES/TIMING LATE SUNDAY NIGHT THRU
WEDNESDAY ALONG WITH HEAVY RAIN POTENTIAL MONDAY NIGHT/TUESDAY.
UPPER RIDGE WILL BE RIGHT OVER THE AREA SUNDAY WITH DRY WEATHER AND
MOSTLY SUNNY SKIES. THIS SHOULD ALLOW TEMPS TO EASILY REACH THE
LOWER 90S INCLUDING ALONG MUCH OF THE IL LAKESHORE AS SOUTHWESTERLY
WINDS APPEAR STRONG ENOUGH THRU MID AFTERNOON TO PREVENT A LAKE
BREEZE. AS THE WINDS DIMINISH IN THE LATER AFTERNOON...WINDS WILL
LIKELY TURN SOUTHEASTERLY ALONG THE IL SHORE COOLING TEMPS A BIT.
WITH DEWPOINTS IN THE UPPER 60S/LOWER 70S...AFTERNOON HEAT INDEX
VALUES COULD CLIMB INTO THE UPPER 90S.
A FRONTAL BOUNDARY WILL MOVE SOUTHEAST ACROSS THE MIDWEST AND
WESTERN LAKES REGION SUNDAY NIGHT REACHING THE AREA MONDAY MORNING.
THE SLOWER TIMING FROM 24 HOURS AGO HAS HELD WITH THE MOST RECENT
GUIDANCE WITH MUCH OF THE AREA STAYING DRY UNTIL EARLY MONDAY
MORNING AND THE BEST CHANCES FOR PRECIP ACROSS NORTHWEST IL TOWARD
DAYBREAK. IT STILL APPEARS THAT PRECIP WILL BE DISSIPATING MONDAY
MORNING BUT TO WHAT EXTENT IS UNCERTAIN. HAVE INTRODUCED MORE OF A
GRADIENT WITH POPS DROPPING OFF TO SLIGHT CHANCE ACROSS THE
SOUTHEAST. POSSIBLE ADDITIONAL DEVELOPMENT MAY OCCUR LATER IN THE
AFTERNOON/EARLY EVENING. PRECIP COVERAGE AND ASSOCIATED CLOUD COVER
MAKE FOR A TRICKY TEMP FORECAST. STILL POSSIBLE TEMPS MAY CLIMB TO
NEAR 90 ACROSS THE SOUTHEAST MONDAY AFTERNOON.
THIS FRONTAL BOUNDARY THEN SLOWS AND STALLS ACROSS THE REGION MONDAY
NIGHT INTO TUESDAY AS AN UPPER WAVE LIFTS NORTHEAST ACROSS THE AREA.
WITH MOISTURE POOLING ALONG THIS BOUNDARY...PERIODS OF HEAVY RAIN
WITH THUNDERSTORMS IS LIKELY SOMEWHERE ACROSS THE REGION...A BIT
EARLY FOR SPECIFICS AND LOCATIONS. AS A STRONGER COLD FRONT MOVES
ACROSS THE AREA TUESDAY INTO TUESDAY NIGHT...THIS SHOULD PUSH THE
PRECIP CHANCES SOUTH OF THE AREA BUT STILL SOME UNCERTAINTY AS TO
HOW FAST THIS OCCURS. ANOTHER WAVE MOVES ACROSS THE AREA LATE NEXT
WEEK AS A LARGE UPPER TROUGH IS PROGGED TO MOVE ACROSS THE LAKES
REGION. GFS/ECMWF HAVE BEEN SHOWING THIS FOR SOME TIME...BUT IT
CONTINUES TO BE DELAYED. IF/WHEN THIS FINALLY ARRIVES...MUCH COOLER
TEMPS AND MUCH LOWER HUMIDITY WITH SPREAD ACROSS THE REGION. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* OUTSIDE CHANCE OF A SHOWER LATE TONIGHT AND SATURDAY MORNING.
* POTENTIAL FOR IFR CIGS OVERNIGHT AND EARLY SATURDAY MORNING.
* CHANCE OF STORMS SATURDAY AFTERNOON.
* POSSIBILITY OF LAKE BREEZE WIND SHIFT LATE IN THE DAY SATURDAY.
//DISCUSSION...UPDATED 00Z...
PRIMARY SURFACE BOUNDARY IS MOVING SLOWLY SOUTHWARD JUST SOUTH OF
THE TRACON AREA AND TAKING THE CONVECTION WITH IT. HOWEVER...A
BROAD UPPER LEVEL DISTURBANCE CENTERED OVER LOWER MICHIGAN
CONTINUES TO PIVOT ACROSS THE REGION. A STRAY SHOWER IS POSSIBLE
ON ITS PERIPHERY OVERNIGHT AND SATURDAY MORNING.
OF GREATER LIKELIHOOD IS THE EXPANSION OF IFR CIGS ON THE WESTERN
PERIPHERY OF LAKE MICHIGAN...WITH SOME ALREADY PRESENT IN FAR
SOUTHEAST WISCONSIN AND AT WAUKEGAN EARLY THIS EVE. WITH THE LAKE
COOLING IN FAR NORTHEAST ILLINOIS THROUGHOUT TODAY...THE
ATMOSPHERE IS SOMEWHAT PRIMED FOR SATURATION IN THE LOW-LEVELS
AFTER DARK. WITH A SLIGHT WIND COMPONENT REMAINING...AT LEAST
THIS EVE...THE PROFILES SUPPORT STRATUS MORE THAN FOG. WILL WATCH
THIS CLOSELY BUT FAVORED TIME FOR CHICAGOLAND TAF SITES WOULD BE
WITHIN THE 07Z-15Z WINDOW.
ANOTHER UNSTABLE DAY IS FORECAST ACROSS THE REGION ON SATURDAY
WITH WEAK FORCING ALOFT...SO ISOLATED STORMS WILL BE
POSSIBLE...INCLUDING ON THE LAKE BREEZE BOUNDARY. THIS FEATURE IS
EXPECTED TO REMAIN EAST OF ORD AND MDW...AT LEAST FOR MOST OF THE
DAY. HOWEVER...IF ANY ISOLATED STORMS DEVELOP NEAR THIS SOURCE OF
CONVERGENCE...THEY COULD DRIFT WESTWARD AND SO HAVE CONTINUED THE
PROB30 FOR THIS CHANCE.
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* LOW IN ANY RAIN DURING THE TAF PERIOD AND LOW-MEDIUM IN TIMING.
* HIGH THAT IFR CIGS WILL FORM IN PARTS OF NORTHEAST ILLINOIS AND
SOUTHEAST WISCONSIN LATER TONIGHT...BUT LOW IF AT ORD AND MDW.
MEDIUM-HIGH IN TIMING IF THEY OCCUR.
* MEDIUM IN WINDS REMAINING SOUTH-SOUTHWEST THROUGHOUT THE ENTIRE
DAY SATURDAY.
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...VFR LIKELY. SOUTH WINDS.
MONDAY...CHANCE OF TSRA. SOUTHWEST WINDS.
TUESDAY...TSRA LIKELY. SOUTHWEST WINDS.
WEDNESDAY...CHANCE OF TSRA. NORTHEAST WINDS.
THURSDAY...SLIGHT CHANCE OF SHRA. NORTH WINDS.
MTF
&&
.MARINE...
315 PM...THE GRADIENT WILL SLOWLY TIGHTEN ACROSS LAKE MICHIGAN
THIS WEEKEND AS A LARGE TROUGH OF LOW PRESSURE OVER THE PLAINS
MOVES EAST WITH HIGH PRESSURE REMAINING OVER THE EASTERN U.S.
SOUTHERLY WINDS WILL LIKELY INCREASE INTO THE 15-25 KT RANGE ON
SUNDAY ESPECIALLY OVER THE NORTHERN PORTION OF THE LAKE. A COLD
FRONT WILL MOVE ACROSS THE LAKE MONDAY AFTERNOON INTO MONDAY
EVENING BUT THIS FRONT WILL SLOW AND STALL ACROSS THE SOUTHERN
LAKES REGION WITH WINDS TURNING BACK SOUTHERLY AHEAD OF ANOTHER
APPROACHING COLD FRONT THAT ARRIVES THURSDAY OR THURSDAY NIGHT
THOUGH CONFIDENCE REGARDING TIMING REMAINS LOW. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
659 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/JASPER COUNTIES OF INDIANA...WITH THE HIGHER
CONCERN EAST INTO CENTRAL INDIANA.
LIKE YESTERDAY...THE LOSS OF DAYTIME HEATING...WE SHOULD SEE
ACTIVITY DIMINISH QUICKLY. THE UPPER LOW LINGERS IN THE REGION
OVERNIGHT. ANOTHER WEAK WAVE WILL ATTEMPT TO MOVE INTO THE UPPER
LEVEL RIDGE THAT WILL BUILD IN FROM THE WEST OVERNIGHT. MANY
GUIDANCE MEMBERS SUGGEST THAT THIS COUPLED WITH SOME RAMPING UP OF
ISENTROPIC LIFT AHEAD OF THIS FEATURE MAY TRIGGER SOME ISOLATED
SHOWERS OR THUNDERSTORMS LATE TONIGHT INTO EARLY SATURDAY. HAVE
MOVED TOWARD THE DRIER NAM SOLUTION AT THIS POINT IN TIME WHICH IS
REFLECTED IN THE EXPERIMENTAL HRRR AND HI-RES NMM/ARW AS WE DO NOT
FEELING FORCING IS STRONG ENOUGH TO TAP INTO ANY ELEVATED
INSTABILITY BUT WILL BE A PERIOD TO WATCH.
THE UPPER RIDGE IS OVER WESTERN ILLINOIS...WITH THE UPPER LOW
INCHING EASTWARD. LOW LEVEL SOUTHWESTERLIES SHOULD ALLOW WARMING ALL
THE WAY TO THE LAKEFRONT WITH 90S INLAND AND UPPER 80S AT THE LAKE.
A WEAKENING OF THE PRESSURE GRADIENT NEAR THE LAKE WOULD SUPPORT A
SE WIND SHIFT NEAR THE LAKE LATER IN THE DAY TO SUPPORT SOME
COOLING. HEAT INDICES WILL GET INTO THE MID TO UPPER 90S IN MANY
SPOTS. HAVE HELD ONTO THE SLIGHT CHANCE POPS FOR TOMORROW
AFTERNOON GIVEN THE MOIST/UNSTABLE ENVIRONMENT...BUT AT THIS POINT
MOST AREAS LOOK TO REMAIN DRY AS THE MAIN TRIGGER IS LACKING.
KMD
&&
.LONG TERM...
SUNDAY THROUGH FRIDAY...
300 PM...MULTIPLE FORECAST CONCERNS INCLUDING HIGH TEMPS SUNDAY
AND MONDAY...PRECIP CHANCES/TIMING LATE SUNDAY NIGHT THRU
WEDNESDAY ALONG WITH HEAVY RAIN POTENTIAL MONDAY NIGHT/TUESDAY.
UPPER RIDGE WILL BE RIGHT OVER THE AREA SUNDAY WITH DRY WEATHER AND
MOSTLY SUNNY SKIES. THIS SHOULD ALLOW TEMPS TO EASILY REACH THE
LOWER 90S INCLUDING ALONG MUCH OF THE IL LAKESHORE AS SOUTHWESTERLY
WINDS APPEAR STRONG ENOUGH THRU MID AFTERNOON TO PREVENT A LAKE
BREEZE. AS THE WINDS DIMINISH IN THE LATER AFTERNOON...WINDS WILL
LIKELY TURN SOUTHEASTERLY ALONG THE IL SHORE COOLING TEMPS A BIT.
WITH DEWPOINTS IN THE UPPER 60S/LOWER 70S...AFTERNOON HEAT INDEX
VALUES COULD CLIMB INTO THE UPPER 90S.
A FRONTAL BOUNDARY WILL MOVE SOUTHEAST ACROSS THE MIDWEST AND
WESTERN LAKES REGION SUNDAY NIGHT REACHING THE AREA MONDAY MORNING.
THE SLOWER TIMING FROM 24 HOURS AGO HAS HELD WITH THE MOST RECENT
GUIDANCE WITH MUCH OF THE AREA STAYING DRY UNTIL EARLY MONDAY
MORNING AND THE BEST CHANCES FOR PRECIP ACROSS NORTHWEST IL TOWARD
DAYBREAK. IT STILL APPEARS THAT PRECIP WILL BE DISSIPATING MONDAY
MORNING BUT TO WHAT EXTENT IS UNCERTAIN. HAVE INTRODUCED MORE OF A
GRADIENT WITH POPS DROPPING OFF TO SLIGHT CHANCE ACROSS THE
SOUTHEAST. POSSIBLE ADDITIONAL DEVELOPMENT MAY OCCUR LATER IN THE
AFTERNOON/EARLY EVENING. PRECIP COVERAGE AND ASSOCIATED CLOUD COVER
MAKE FOR A TRICKY TEMP FORECAST. STILL POSSIBLE TEMPS MAY CLIMB TO
NEAR 90 ACROSS THE SOUTHEAST MONDAY AFTERNOON.
THIS FRONTAL BOUNDARY THEN SLOWS AND STALLS ACROSS THE REGION MONDAY
NIGHT INTO TUESDAY AS AN UPPER WAVE LIFTS NORTHEAST ACROSS THE AREA.
WITH MOISTURE POOLING ALONG THIS BOUNDARY...PERIODS OF HEAVY RAIN
WITH THUNDERSTORMS IS LIKELY SOMEWHERE ACROSS THE REGION...A BIT
EARLY FOR SPECIFICS AND LOCATIONS. AS A STRONGER COLD FRONT MOVES
ACROSS THE AREA TUESDAY INTO TUESDAY NIGHT...THIS SHOULD PUSH THE
PRECIP CHANCES SOUTH OF THE AREA BUT STILL SOME UNCERTAINTY AS TO
HOW FAST THIS OCCURS. ANOTHER WAVE MOVES ACROSS THE AREA LATE NEXT
WEEK AS A LARGE UPPER TROUGH IS PROGGED TO MOVE ACROSS THE LAKES
REGION. GFS/ECMWF HAVE BEEN SHOWING THIS FOR SOME TIME...BUT IT
CONTINUES TO BE DELAYED. IF/WHEN THIS FINALLY ARRIVES...MUCH COOLER
TEMPS AND MUCH LOWER HUMIDITY WITH SPREAD ACROSS THE REGION. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* OUTSIDE CHANCE OF A SHOWER LATE TONIGHT AND SATURDAY MORNING.
* POTENTIAL FOR IFR CIGS OVERNIGHT AND SATURDAY MORNING.
* CHANCE OF STORMS SATURDAY AFTERNOON.
* POSSIBILITY OF LAKE BREEZE WIND SHIFT LATE IN THE DAY SATURDAY.
//DISCUSSION...UPDATED 00Z...
PRIMARY SURFACE BOUNDARY IS MOVING SLOWLY SOUTHWARD JUST SOUTH OF
THE TRACON AREA AND TAKING THE CONVECTION WITH IT. HOWEVER...A
BROAD UPPER LEVEL DISTURBANCE CENTERED OVER LOWER MICHIGAN
CONTINUES TO PIVOT ACROSS THE REGION. A STRAY SHOWER IS POSSIBLE
ON ITS PERIPHERY OVERNIGHT AND SATURDAY MORNING.
OF GREATER LIKELIHOOD IS THE EXPANSION OF IFR CIGS ON THE WESTERN
PERIPHERY OF LAKE MICHIGAN...WITH SOME ALREADY PRESENT IN FAR
SOUTHEAST WISCONSIN AND AT WAUKEGAN EARLY THIS EVE. WITH THE LAKE
COOLING IN FAR NORTHEAST ILLINOIS THROUGHOUT TODAY...THE
ATMOSPHERE IS SOMEWHAT PRIMED FOR SATURATION IN THE LOW-LEVELS
AFTER DARK. WITH A SLIGHT WIND COMPONENT REMAINING...AT LEAST
THIS EVE...THE PROFILES SUPPORT STRATUS MORE THAN FOG. WILL WATCH
THIS CLOSELY BUT FAVORED TIME FOR CHICAGOLAND TAF SITES WOULD BE
WITHIN THE 07Z-15Z WINDOW.
ANOTHER UNSTABLE DAY IS FORECAST ACROSS THE REGION ON SATURDAY
WITH WEAK FORCING ALOFT...SO ISOLATED STORMS WILL BE
POSSIBLE...INCLUDING ON THE LAKE BREEZE BOUNDARY. THIS FEATURE IS
EXPECTED TO REMAIN EAST OF ORD AND MDW...AT LEAST FOR MOST OF THE
DAY. HOWEVER...IF ANY ISOLATED STORMS DEVELOP NEAR THIS SOURCE OF
CONVERGENCE...THEY COULD DRIFT WESTWARD AND SO HAVE CONTINUED THE
PROB30 FOR THIS CHANCE.
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* LOW IN ANY RAIN DURING THE TAF PERIOD AND LOW-MEDIUM IN TIMING.
* HIGH THAT IFR CIGS WILL FORM IN PARTS OF NORTHEAST ILLINOIS AND
SOUTHEAST WISCONSIN LATER TONIGHT...BUT LOW IF AT ORD AND MDW.
MEDIUM-HIGH IN TIMING IF THEY OCCUR.
* MEDIUM IN WINDS REMAINING SOUTH-SOUTHWEST THROUGHOUT THE ENTIRE
DAY SATURDAY.
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...VFR LIKELY. SOUTH WINDS.
MONDAY...CHANCE OF TSRA. SOUTHWEST WINDS.
TUESDAY...TSRA LIKELY. SOUTHWEST WINDS.
WEDNESDAY...CHANCE OF TSRA. NORTHEAST WINDS.
THURSDAY...SLIGHT CHANCE OF SHRA. NORTH WINDS.
MTF
&&
.MARINE...
315 PM...THE GRADIENT WILL SLOWLY TIGHTEN ACROSS LAKE MICHIGAN
THIS WEEKEND AS A LARGE TROUGH OF LOW PRESSURE OVER THE PLAINS
MOVES EAST WITH HIGH PRESSURE REMAINING OVER THE EASTERN U.S.
SOUTHERLY WINDS WILL LIKELY INCREASE INTO THE 15-25 KT RANGE ON
SUNDAY ESPECIALLY OVER THE NORTHERN PORTION OF THE LAKE. A COLD
FRONT WILL MOVE ACROSS THE LAKE MONDAY AFTERNOON INTO MONDAY
EVENING BUT THIS FRONT WILL SLOW AND STALL ACROSS THE SOUTHERN
LAKES REGION WITH WINDS TURNING BACK SOUTHERLY AHEAD OF ANOTHER
APPROACHING COLD FRONT THAT ARRIVES THURSDAY OR THURSDAY NIGHT
THOUGH CONFIDENCE REGARDING TIMING REMAINS LOW. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1225 PM CDT THU SEP 3 2015
.UPDATE...1153 AM CDT
MINOR REFINEMENTS TO THE TIMING OF POPS TODAY. THIS AFTERNOON...CU
STARTING TO BLOSSOM ACROSS THE REGION WITH THE BEST DEVELOPMENT
SO FAR ACROSS FAR NORTHEAST IL INCLUDING LAKE COUNTY AND NORTHERN
COOK COUNTY. CANNOT RULE AN ISOLATED STORM DEVELOPING OVER THESE
AREAS EARLY THIS AFTERNOON WITH RAP SOUNDINGS SHOWING THE
BOUNDARY LAYER UNCAPPED...HOWEVER FORCING IS FAIRLY NON-EXISTENT
WITH WEAK MID LEVEL HEIGHT RISES IN PLACE WHICH SHOULD KEEP
CONVECTION IN CHECK MOST OF THE AFTERNOON. THIS WILL CHANGE
STARTING EARLY THIS EVENING AS A LAKE BREEZE POSSIBLY ENHANCED BY
OUTFLOW FROM CONVECTION OVER THE LAKE DROPS INTO NORTHERN
ILLINOIS. THIS IS EXPECTED TO SERVE THE FOCUS FOR ISOLATED TO
SCATTERED THUNDERSTORMS. LATEST RUNS OF THE HRRR AND RAP SHOW THIS
OCCURRING STARTING AROUND 22-00Z WITH THE NAM RUNNING SLIGHTLY
SLOWER. BUMPED BACK THE TIMING OF THE HIGHEST POPS TO BETTER MATCH
THESE THOUGHTS.
DEUBELBEISS
&&
.SHORT TERM...
310 AM CDT
THROUGH FRIDAY...
PRIMARY CONCERN IN SHORT TERM IS CONVECTIVE CHANCES TODAY AND
SECONDARILY TEMPS. MCV OVER NORTHERN LAKE MICHIGAN WILL CONTINUE TO
PUSH VERY SLOWLY EAST INTO NORTHERN LOWER MICHIGAN TODAY. TRAILING
WEST-EAST LINE OF STORMS ACROSS EAST CENTRAL WISCONSIN HAS BEEN
SAGGING VERY SLOWLY SOUTHWARD AND AT ITS CURRENT PACE LOOKS TO MAKE
IT INTO THE HEART OF OUR CWA BY EARLY AFTERNOON. GIVEN RELATIVELY
WEAK CAPPING AND UNSEASONABLY WARM/HUMID AIR MASS QUITE PLAUSIBLE
THAT ISOLD TO POSSIBLY SCTD THUNDERSTORMS COULD DEVELOP ALONG THIS
BOUNDARY THIS AFTERNOON OR PERHAPS ALONG LAKE BREEZE LATE THIS
AFTERNOON AND EVENING. CONVECTIVE ALLOWING MODELS HAVE BEEN HAVING
ABSOLUTE FITS HANDLING THIS WEAKLY FORCED CONVECTION THE PAST COUPLE
DAYS WHICH LENDS ITSELF TO LOWER THAN AVERAGE CONFIDENCE IN HOW
THINGS EVOLVE TODAY. WITH SHORTWAVE MOVING EAST TONIGHT AND SOME
NOCTURNAL STABILIZATION WOULD ANTICIPATE ANY CONVECTION THAT DOES
DEVELOP TO DISSIPATE THIS EVENING.
ASSUMING CONVECTION AND CLOUD COVER ARE NOT OVERLY EXTENSIVE THROUGH
MID-AFTERNOON...WHICH WOULD APPEAR TO BE A GOOD ASSUMPTION AT THIS
POINT...THEN HIGHS TODAY WOULD LIKELY BE IN THE BALL PARK OF WHERE
THEY WERE YESTERDAY AROUND 90 DEGREES. IF CONVECTIVE OUTFLOW
ENHANCES A LAKE BREEZE THEN IT COULD TURN COOLER NEAR THE LAKE THIS
AFTERNOON...BUT THIS DOESNT APPEAR TO BE MOST LIKELY SCENARIO AT
THIS TIME SO DIDNT REFLECT THAT IN WIND/TEMP GRIDS.
WEAKNESS BETWEEN MAIN UPPER RIDGE AND WEAK RIDGE OVER QUEBEC SHOULD
RESULT IN WEAK CAPPING AT BEST FRIDAY AND A CONTINUED SLIGHT CHANCE
OF AT LEAST ISOLATED STORMS IN THE AFTERNOON AND EVENING. LAKE
BREEZE LOOKS MORE LIKELY TO KEEP LAKESHORE AREAS COOLER FRIDAY BUT
INLAND TEMPS SHOULD AGAIN WARM INTO THE UPPER 80S TO NEAR 90.
IZZI
&&
.LONG TERM...
310 AM CDT
FRIDAY NIGHT THROUGH WEDNESDAY...
UPPER RIDGE LOOKS TO FLEX A BIT MORE NORTHEAST INTO THE REGION OVER
THE WEEKEND AND WHILE ISOLATED STORMS CANNOT TOTALLY BE RULED
OUT...CHANCES LOOK SLIME WITH SATURDAY AND SUNDAY GENERALLY LOOKING
MAINLY RAIN FREE AT THIS POINT. TEMPERATURES LOOKS TO REMAIN VERY
WARM TO BORDERLINE HOT AND CONTINUED HUMID. HIGHS SHOULD EASILY
CLIMB INTO THE UPPER 80S WITH LOW 90S CERTAINLY POSSIBLE. LAKE
BREEZE IS POSSIBLE SATURDAY BUT LOOKS LESS LIKELY AT THIS POINT ON
SUNDAY.
COLD FRONT SHOULD BEGIN TO APPROACH FROM THE NORTHWEST SUNDAY NIGHT
OR MONDAY. IN GENERAL...MEDIUM RANGE GUIDANCE HAS SPED UP THE FRONT
SOME COMPARED TO RUNS 24 HOURS AGO. NOT CONVINCED IT WILL BE THIS
QUICK AND WORRIED THAT BLENDED MODEL HIGHS IN THE MID 80S MONDAY MAY
END UP BEING A BIT TOO COOL...BUT GIVEN RECENT MODEL TRENDS DIDNT
MAKE ANY CHANGES AT THIS POINT. IT DOES APPEAR AS THOUGH WE COULD
GET A BREAK FROM THE LATE RESURGENCE OF SUMMER BY THE MIDDLE OF NEXT
WEEK WITH HIGHS RETURNING INTO THE 70S AGAIN.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* TSRA/SHRA POSSIBLE WITH INCREASING CHANCES LATER THIS AFTERNOON
AND EVENING...WITH ISOLATED ACTIVITY LINGERING OVERNIGHT.
* ABRUPT WIND SHIFT TO AN NNE DIRECTION LATE THIS AFTERNOON OR EARLY
EVENING WITH WINDS ABOVE 10 KT POSSIBLE FOR A BRIEF TIME.
* MVFR CIGS THIS EVENING.
KMD
//DISCUSSION...UPDATED 18Z...
DESTABILIZATION CONTINUES ACROSS THE AREA THIS AFTERNOON WITH A BIT
MORE WIDESPREAD CUMULUS DEVELOPMENT ONGOING. SW WINDS ARE STRONG
ENOUGH TO KEEP A LAKE BREEZE AT BAY FOR THIS AFTERNOON...BUT
ATTENTION SHIFTS TO SOUTHWARD MOVING FRONTAL BOUNDARY MAKING DECENT
HEADWAY DOWN THE WESTERN SHORE OF LAKE MICHIGAN. WINDS SHIFT TO AN
NNE DIRECTION BEHIND THIS BOUNDARY...AND TO THIS POINT WINDS HAVE
LARGELY HELD UNDER 10 KT. THIS SHOULD LARGELY BE THE TREND AS THE
BOUNDARY MOVES SOUTH LATER THIS AFTERNOON AND EVENING...THOUGH A
BRIEF PERIOD OF WINDS IN EXCESS OF 10 KT ARE POSSIBLE.
OTHER CONCERN IS WITH CONVECTION ALONG THE LAKE BREEZE/FRONT AS LOW
PRESSURE IN NORTHWEST WISCONSIN MOVES SOUTH. SOME GUIDANCE IS TRYING
TO BREAK OUT SHOWERS THIS AFTERNOON...WHICH IS CERTAINLY POSSIBLE
GIVEN THE UNSTABLE ENVIRONMENT...BUT WITH THE FRONT/UPPER LOW NOT
ARRIVING UNTIL LATER THIS AFTERNOON AND EVENING...THIS STILL APPEARS
TO BE THE BEST FOCUS FOR THUNDERSTORMS. TIMING CONFIDENCE IS ONLY
MEDIUM AT THIS POINT...AND COVERAGE CONCERNS PRECLUDES MORE THAN A
VCTS MENTION AS WELL. MVFR CLOUDS WILL ACCOMPANY THE WIND
SHIFT...WITH AT LEAST A PERIOD OF BROKEN CIGS THROUGH THE
EVENING....POSSIBLY LONGER.
THE BOUNDARY WILL LINGER OVER THE AREA IN THE OVERNIGHT HOURS...AND
ENERGY ON THE BACK SIDE OF THE UPPER LOW CENTER IN MICHIGAN WHICH
WILL STALL OUT WILL MEAN ISOLATED DEVELOPMENT MAY CONTINUE
OVERNIGHT. CONFIDENCE IN COVERAGE IS LOW...THUS THE DRY TAF
FORECAST FOR OVERNIGHT.
KMD
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* LOW-MEDIUM WITH TSRA/SHRA CHANCES/COVERAGE THROUGH THIS EVENING.
MEDIUM ON TIMING.
* MEDIUM-HIGH WITH WIND SPEED/DIRECTION...MEDIUM ON TIMING OF WIND
SHIFT AND IF IT WILL STAY UNDER 10 KT WHEN IT OCCURS.
* HIGH ON MVFR CLOUDS FORMING THIS EVENING...LOW ON HOW LONG THEY
LAST.
KMD
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR.
SATURDAY...SLIGHT CHANCE OF TSRA.
SUNDAY...CHANCE OF TSRA LATE.
MONDAY...CHANCE OF TSRA.
TUESDAY...SLIGHT CHANCE OF TSRA.
WEDNESDAY...CHANCE OF TSRA.
RODRIGUEZ
&&
.MARINE...
428 AM CDT
AS A BOUNDARY REMAINS SITUATED ACROSS THE NORTHERN PORTIONS OF
THE LAKE THIS MORNING...A VARYING WIND FIELD IS OCCURRING ACROSS
THE LAKE. OVER THE NORTH...EAST NORTHEAST WINDS ARE OCCURRING AND
ACROSS THE SOUTH...SOUTHWEST WINDS ARE BEING OBSERVED. THIS WILL
LIKELY PERSIST FOR MOST OF TODAY...BUT WITH THE SOUTHWEST WINDS
ACROSS THE SOUTHERN PART OF LAKE TURNING MORE SOUTHEAST THIS
AFTERNOON. INCREASED WINDS OVER THE NORTH HALF TO 10 TO 20 KT FOR
THIS MORNING BUT HAVE THEM DIMINISHING IN THE AFTERNOON.
HOWEVER...DO THINK ITS POSSIBLE THAT 10 TO 20 KT WINDS COULD STILL
BE POSSIBLE IN THE AFTERNOON. WAVES SHOULD STAY CONFINED TO 1 TO 3
FEET TODAY AND TONIGHT BUT WITH THUNDERSTORMS PUSHING OVER THE
LAKE EARLY THIS MORNING...ASSOCIATED HIGHER WINDS COULD HELP TO
BRIEFLY BUILD THESE WAVES.
RODRIGUEZ
&&
.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
1157 AM CDT THU SEP 3 2015
.UPDATE...
1153 AM CDT
MINOR REFINEMENTS TO THE TIMING OF POPS TODAY. THIS AFTERNOON...CU
STARTING TO BLOSSOM ACROSS THE REGION WITH THE BEST DEVELOPMENT
SO FAR ACROSS FAR NORTHEAST IL INCLUDING LAKE COUNTY AND NORTHERN
COOK COUNTY. CANNOT RULE AN ISOLATED STORM DEVELOPING OVER THESE
AREAS EARLY THIS AFTERNOON WITH RAP SOUNDINGS SHOWING THE
BOUNDARY LAYER UNCAPPED...HOWEVER FORCING IS FAIRLY NON-EXISTANT
WITH WEAK MID LEVEL HEIGHT RISES IN PLACE WHICH SHOULD KEEP
CONVECTION IN CHECK MOST OF THE AFTERNOON. THIS WILL CHANGE
STARTING EARLY THIS EVENING AS A LAKE BREEZE POSSIBLY ENHANCED BY
OUTFLOW FROM CONVECTION OVER THE LAKE DROPS INTO NORTHERN
ILLINOIS. THIS IS EXPECTED TO SERVE THE FOCUS FOR ISOLATED TO
SCATTERED THUNDERSTORMS. LATEST RUNS OF THE HRRR AND RAP SHOW THIS
OCCURRING STARTING AROUND 22-00Z WITH THE NAM RUNNING SLIGHTLY
SLOWER. BUMPED BACK THE TIMING OF THE HIGHEST POPS TO BETTER MATCH
THESE THOUGHTS.
DEUBELBEISS
&&
.SHORT TERM...
310 AM CDT
THROUGH FRIDAY...
PRIMARY CONCERN IN SHORT TERM IS CONVECTIVE CHANCES TODAY AND
SECONDARILY TEMPS. MCV OVER NORTHERN LAKE MICHIGAN WILL CONTINUE TO
PUSH VERY SLOWLY EAST INTO NORTHERN LOWER MICHIGAN TODAY. TRAILING
WEST-EAST LINE OF STORMS ACROSS EAST CENTRAL WISCONSIN HAS BEEN
SAGGING VERY SLOWLY SOUTHWARD AND AT ITS CURRENT PACE LOOKS TO MAKE
IT INTO THE HEART OF OUR CWA BY EARLY AFTERNOON. GIVEN RELATIVELY
WEAK CAPPING AND UNSEASONABLY WARM/HUMID AIR MASS QUITE PLAUSIBLE
THAT ISOLD TO POSSIBLY SCTD THUNDERSTORMS COULD DEVELOP ALONG THIS
BOUNDARY THIS AFTERNOON OR PERHAPS ALONG LAKE BREEZE LATE THIS
AFTERNOON AND EVENING. CONVECTIVE ALLOWING MODELS HAVE BEEN HAVING
ABSOLUTE FITS HANDLING THIS WEAKLY FORCED CONVECTION THE PAST COUPLE
DAYS WHICH LENDS ITSELF TO LOWER THAN AVERAGE CONFIDENCE IN HOW
THINGS EVOLVE TODAY. WITH SHORTWAVE MOVING EAST TONIGHT AND SOME
NOCTURNAL STABILIZATION WOULD ANTICIPATE ANY CONVECTION THAT DOES
DEVELOP TO DISSIPATE THIS EVENING.
ASSUMING CONVECTION AND CLOUD COVER ARE NOT OVERLY EXTENSIVE THROUGH
MID-AFTERNOON...WHICH WOULD APPEAR TO BE A GOOD ASSUMPTION AT THIS
POINT...THEN HIGHS TODAY WOULD LIKELY BE IN THE BALL PARK OF WHERE
THEY WERE YESTERDAY AROUND 90 DEGREES. IF CONVECTIVE OUTFLOW
ENHANCES A LAKE BREEZE THEN IT COULD TURN COOLER NEAR THE LAKE THIS
AFTERNOON...BUT THIS DOESNT APPEAR TO BE MOST LIKELY SCENARIO AT
THIS TIME SO DIDNT REFLECT THAT IN WIND/TEMP GRIDS.
WEAKNESS BETWEEN MAIN UPPER RIDGE AND WEAK RIDGE OVER QUEBEC SHOULD
RESULT IN WEAK CAPPING AT BEST FRIDAY AND A CONTINUED SLIGHT CHANCE
OF AT LEAST ISOLATED STORMS IN THE AFTERNOON AND EVENING. LAKE
BREEZE LOOKS MORE LIKELY TO KEEP LAKESHORE AREAS COOLER FRIDAY BUT
INLAND TEMPS SHOULD AGAIN WARM INTO THE UPPER 80S TO NEAR 90.
IZZI
&&
.LONG TERM...
310 AM CDT
FRIDAY NIGHT THROUGH WEDNESDAY...
UPPER RIDGE LOOKS TO FLEX A BIT MORE NORTHEAST INTO THE REGION OVER
THE WEEKEND AND WHILE ISOLATED STORMS CANNOT TOTALLY BE RULED
OUT...CHANCES LOOK SLIME WITH SATURDAY AND SUNDAY GENERALLY LOOKING
MAINLY RAIN FREE AT THIS POINT. TEMPERATURES LOOKS TO REMAIN VERY
WARM TO BORDERLINE HOT AND CONTINUED HUMID. HIGHS SHOULD EASILY
CLIMB INTO THE UPPER 80S WITH LOW 90S CERTAINLY POSSIBLE. LAKE
BREEZE IS POSSIBLE SATURDAY BUT LOOKS LESS LIKELY AT THIS POINT ON
SUNDAY.
COLD FRONT SHOULD BEGIN TO APPROACH FROM THE NORTHWEST SUNDAY NIGHT
OR MONDAY. IN GENERAL...MEDIUM RANGE GUIDANCE HAS SPED UP THE FRONT
SOME COMPARED TO RUNS 24 HOURS AGO. NOT CONVINCED IT WILL BE THIS
QUICK AND WORRIED THAT BLENDED MODEL HIGHS IN THE MID 80S MONDAY MAY
END UP BEING A BIT TOO COOL...BUT GIVEN RECENT MODEL TRENDS DIDNT
MAKE ANY CHANGES AT THIS POINT. IT DOES APPEAR AS THOUGH WE COULD
GET A BREAK FROM THE LATE RESURGENCE OF SUMMER BY THE MIDDLE OF NEXT
WEEK WITH HIGHS RETURNING INTO THE 70S AGAIN.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* TSRA/SHRA POSSIBLE LATE THIS AFTERNOON AND EVENING.
* ABRUPT WIND SHIFT TO AN ENE DIRECTION LATE THIS AFTERNOON OR
EARLY EVENING WITH WINDS ABOVE 10 KT POSSIBLE.
* MVFR CIGS THIS EVENING
RODRIGUEZ
//DISCUSSION...UPDATED 12Z...
VFR CONDITIONS AND LIGHT SOUTHERLY WINDS IN PLACE THIS
MORNING...WHILE ANY PRECIP ACROSS THE REGION IS CURRENTLY TO THE
NORTH OF ALL THE TERMINALS. THIS WILL LIKELY CONTINUE...WITH ANY
FURTHER DEVELOPMENT THIS MORNING STAYING TO THE NORTH/NORTHEAST.
INCREASING SOUTHWEST WINDS THROUGH MIDDAY/EARLY AFTERNOON WILL
LIKELY OBSERVE A WIND SHIFT TO THE EAST...OWING TO BOUNDARY/LAKE
BREEZE. LOWER CONFIDENCE WITH EXACT TIMING AS WELL AS SPEED BEHIND
THE FRONT. AT THIS TIME...THINK SPEEDS WILL STAY BELOW 10 KT.
HOWEVER...SOME GUIDANCE IS HINTING AT POSSIBLE SUSTAINED SPEEDS
ABOVE 10 KT THROUGH THIS EVENING. THIS BOUNDARY COULD ALSO SERVE
AS A FOCUS FOR PRECIP DEVELOPMENT THIS AFTERNOON INTO THE EVENING.
WITH AT LEAST SCATTERED DEVELOPMENT POSSIBLE...HAVE MAINTAINED A
VCSH IN THE TAFS. WILL NEED TO MONITOR SPEEDS BEHIND WIND SHIFT AS
WELL AS PRECIP CHANCES/COVERAGE LATER THIS AFTERNOON.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* LOW-MEDIUM WITH TSRA/SHRA CHANCES/COVERAGE THIS
AFTERNOON/EVENING. MEDIUM ON TIMING IF IT OCCURS.
* MEDIUM HIGH WITH WIND SPEED/DIRECTION...MEDIUM ON TIMING OF
WIND SHIFT AND IF IT WILL STAY UNDER 10 KT WHEN IT OCCURS.
* MEDIUM ON MVFR CLOUDS FORMING THIS EVENING...LOW ON HOW LONG
THEY LAST.
KMD
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR.
SATURDAY...SLIGHT CHANCE OF TSRA.
SUNDAY...CHANCE OF TSRA LATE.
MONDAY...CHANCE OF TSRA.
TUESDAY...SLIGHT CHANCE OF TSRA.
WEDNESDAY...CHANCE OF TSRA.
RODRIGUEZ
&&
.MARINE...
428 AM CDT
AS A BOUNDARY REMAINS SITUATED ACROSS THE NORTHERN PORTIONS OF
THE LAKE THIS MORNING...A VARYING WIND FIELD IS OCCURRING ACROSS
THE LAKE. OVER THE NORTH...EAST NORTHEAST WINDS ARE OCCURRING AND
ACROSS THE SOUTH...SOUTHWEST WINDS ARE BEING OBSERVED. THIS WILL
LIKELY PERSIST FOR MOST OF TODAY...BUT WITH THE SOUTHWEST WINDS
ACROSS THE SOUTHERN PART OF LAKE TURNING MORE SOUTHEAST THIS
AFTERNOON. INCREASED WINDS OVER THE NORTH HALF TO 10 TO 20 KT FOR
THIS MORNING BUT HAVE THEM DIMINISHING IN THE AFTERNOON.
HOWEVER...DO THINK ITS POSSIBLE THAT 10 TO 20 KT WINDS COULD STILL
BE POSSIBLE IN THE AFTERNOON. WAVES SHOULD STAY CONFINED TO 1 TO 3
FEET TODAY AND TONIGHT BUT WITH THUNDERSTORMS PUSHING OVER THE
LAKE EARLY THIS MORNING...ASSOCIATED HIGHER WINDS COULD HELP TO
BRIEFLY BUILD THESE WAVES.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS DES MOINES IA
332 PM CDT THU SEP 3 2015
.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
MCW 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 ATTM.
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 LLJ 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
LONGWAVE 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
WITH THE UPPER LEVEL RIDGE FIRMLY PLANTED ABOVE...ANYTHING OF
CONSEQUENCE WILL STAY TO THE WEST AND NORTHWEST OF THE TAF SITES.
MODEL SOUNDINGS HINT AT SOME LOCALIZED FOG TOMORROW MORNING...BUT
WITH HRRR DEPICTING OTHERWISE AND LITTLE CHANGE OVERNIGHT
OTHERWISE...HAVE KEPT FOG MENTIONS OUT FOR THIS ITERATION.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...BEERENDS
AVIATION...CURTIS
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1236 PM CDT THU SEP 3 2015
...18Z AVIATION UPDATE...
.SHORT TERM /TODAY/...
ISSUED AT 335 AM CDT THU SEP 3 2015
PRECIPITATION CHANCES TODAY WILL BE MAIN FORECAST CONCERN. HAVE SEEN
DEVELOPMENT OF ONGOING LIGHT AND SCATTERED SHOWERS ACROSS SW
PORTIONS OF STATE...GENERALLY ALONG THE NOSE OF LLJ...AND EXPECT
THIS PRECIPITATION TO CONTINUE INTO THE EARLY MORNING
HOURS...DISSIPATING QUICKLY AFTER 12Z AS FORCING DIMINISHES. HAVE
TRENDED TOWARDS HIGH RES SOLUTIONS...THOUGH MAY BE TOO AGGRESSIVE
WITH EXTENT OF NORTHERN EDGE OF PRECIPITATION AND PERSISTENCE.
CHANCES FOR PRECIPITATION WILL THEN SHIFT TO THE NORTHEASTERN
PORTIONS OF THE CWA LATE IN THE PERIOD. MODELS INDICATE DECENT
INSTABILITY ACROSS THE AREA...THOUGH SOUNDINGS SHOWING A WEAK CAP
WHICH SHOULD BE SUFFICIENT TO KEEP PRECIPITATION CHANCES OUT OF CWA.
HAVE THEREFORE KEPT FORECAST DRY...WITH BEST FORCING FURTHER EAST OF
THE AREA. HOWEVER...DO NOT HAVE HIGH CONFIDENCE AND MAY SEE
THUNDERSTORMS DEVELOP IN THE AFTERNOON IN THIS AREA.
HAVE KEPT TEMPERATURES NEAR GOING...TOWARDS THE HIGHER GUIDANCE.
WITH GOOD SOUTHERLY SURFACE FLOW AND WARMER TEMPERATURES ALOFT
SHOULD SEE TEMPERATURES WARM TODAY. HUMID CONDITIONS WILL PERSIST
WITH HEAT INDEX VALUES GENERALLY 95-100 DEGREES IN THE AFTERNOON.
.LONG TERM /TONIGHT THROUGH WEDNESDAY/...
ISSUED AT 335 AM CDT THU SEP 3 2015
A FEW MORE DAYS OF SUMMER WHILE THE UPPER RIDGE REMAINS OVER THE
STATE. HIGH TEMPERATURES IN THE MID 80S TO LOWER 90S ARE EXPECTED TO
LAST THROUGH SUNDAY HOWEVER CHANGE IS ON THE WAY. SEVERAL FEATURES
TO MONITOR THROUGH THE PERIOD. THE FIRST WILL BE THE INCREASING
MONSOONAL FLOW AS AN UPPER LOW DIGS INTO THE PACIFIC NORTHWEST
FRIDAY INTO SATURDAY. THIS FLOW ENHANCE THE MOISTURE TRANSPORT INTO
THE REGION AND ALSO WILL INGEST TROPICAL VORTICITY FRAGMENTS FROM
THE SYSTEM CURRENTLY TROPICAL STORM KEVIN. THIS WILL BRING
INCREASING CHANCES FOR THUNDERSTORMS SATURDAY NIGHT INTO SUNDAY
AND WILL BE FOLLOWED BY ADDITIONAL CHANCES SUNDAY NIGHT AS A COLD
FRONT PASSES THROUGH THE STATE.
THIS WILL BE THE BEGINNING OF AN EVOLUTION TO A MORE FALL LIKE
PATTERN THAT OCCUR THROUGH THE PERIOD AS THE UPPER RIDGE IS
SUPPRESSES TO SOUTH AND EAST WHILE THE PACIFIC UPPER LOW LIFTS INTO
SOUTH CENTRAL CANADA AND WILL HELP DRIVE THE BOUNDARY INTO THE
STATE. THIS WILL PLACE THE MIDWEST IN A MORE PROGRESSIVE ZONAL FLOW
NEXT WEEK. THE BOUNDARY SUNDAY NIGHT WILL NOT BE ABLE TO DROP TOO
FAR SOUTH DUE TO THE ZONAL FLOW AND WILL LIFT BACK NORTH AS A WARM
FRONT TUESDAY. A STRONGER BOUNDARY WILL PUSH THROUGH TUESDAY NIGHT
INTO WEDNESDAY. EVEN COOLER AIR IS LIKELY TO ARRIVE JUST BEYOND THE
EXTENDED AND LIKELY SIGNALS THE END TO THE HOT AND HUMID WEATHER FOR
THE YEAR BEYOND THIS WEEKEND. WITH SUCH AN ACTIVE PATTERN AND STRONG
SYSTEMS...CAN NOT DISCOUNT A FEW SEVERE STORMS NEXT WEEK.
&&
.AVIATION...03/18Z
ISSUED AT 1229 PM CDT THU SEP 3 2015
WITH THE UPPER LEVEL RIDGE FIRMLY PLANTED ABOVE...ANYTHING OF
CONSEQUENCE WILL STAY TO THE WEST AND NORTHWEST OF THE TAF SITES.
MODEL SOUNDINGS HINT AT SOME LOCALIZED FOG TOMORROW MORNING...BUT
WITH HRRR DEPICTING OTHERWISE AND LITTLE CHANGE OVERNIGHT
OTHERWISE...HAVE KEPT FOG MENTIONS OUT FOR THIS ITERATION.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...AWB
LONG TERM...DONAVON
AVIATION...CURTIS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1138 PM CDT WED SEP 2 2015
...Update to aviation forecast discussion...
.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 06Z TAFS THROUGH 06Z Thursday NIGHT)
ISSUED AT 1138 PM CDT WED SEP 2 2015
For the 06z TAFs, VFR conditions are expected through the period.
There is a slight chance for a few isolated showers to develop early
Thursday morning, however confidence is not high enough on the
probability of these showers developing (let alone where they would
develop) to include in the TAFs at this time, but will continue to
monitor this potential. Otherwise, southerly winds will become
more gusty Thursday afternoon.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Omitt
LONG TERM...GDP
AVIATION...Hennecke
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
214 PM EDT THU SEP 3 2015
.UPDATE...
ISSUED AT 214 PM EDT THU SEP 3 2015
ISOLATED SHOWERS AND THUNDERSTORMS HAVE MANAGED TO DOT THE AREA
EVEN FURTHER SOUTHWEST. HAVE INCLUDED MOST OF THE AREA WITH AT
LEAST ISOLATED POPS FOR THE REST OF THE AFTERNOON BASED ON THE
RADAR TRENDS. FRESHENED UP THE HOURLY TEMPERATURES AND DEW POINTS
AS WELL TO JIVE BETTER WITH THE LATEST TRENDS IN OBSERVATIONS.
UPDATE ISSUED AT 1214 PM EDT THU SEP 3 2015
A FEW SHORT-LIVED SHOWERS MANAGED TO DEVELOP ACROSS PORTIONS OF
EASTERN PIKE COUNTY EARLIER...HOWEVER THESE HAVE SINCE DISSIPATED.
THE CU FIELD HAS BEEN MORE PREVALENT IN THE EAST SO FAR AND THE
LATEST HRRR MODEL OUTPUT CONTINUES TO SUGGEST THE BETTER POTENTIAL
FOR ANY ISOLATED ACTIVITY FOR THOSE LOCATIONS. DID GO AHEAD AND
ADD THUNDER FOR TODAY GIVEN THE MODERATELY STEEP LOW LEVEL LAPSE
RATES TO DEVELOP DURING PEAK HEATING. HIGHS TODAY LOOK ON
TARGET...WITH MOST LOCATIONS REACHING AROUND THE 90 DEGREE MARK.
UPDATE ISSUED AT 736 AM EDT THU SEP 3 2015
NO UPDATE THIS MORNING AS FORECAST IS ON TRACK. LOTS OF VALLEY FOG
OUT THERE SHOULD AND IT SHOULD BE BURNING OFF OVER THE NEXT FEW
HOURS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 257 AM EDT THU SEP 3 2015
NO PATTERN CHANGE EXPECTED THROUGH FRIDAY. THIS WILL MEAN A
CONTINUATION OF UNSEASONABLY WARM AND HUMID CONDITIONS THROUGH THE
END OF THE WEEK. A WEAK UPPER LEVEL TROUGH WILL CONTINUE TO
PRODUCE A MEAGER CHANCE OF A FEW AFTERNOON SHOWERS OR STORMS TODAY
AND AGAIN FRIDAY. HOWEVER...AS FAR AS TODAY GOES...HI RES MODELS
ARE INDICATING THAT WE MAY BE IN A HOLE WITH REGARDS TO CONVECTION
TODAY...KEEPING EVERYTHING FARTHER EAST. THERE DOES APPEAR TO BE A
WAVE IN THE FLOW TO OUR NORTHEAST...BUT REALLY SHOULD CLIP OUR
AREA. THUS...WILL DOWNPLAY PRECIPITATION CHANCES TODAY...JUST
GOING WITH A SLIGHT CHANCE OF A SHOWER IN THE FAR EAST/SOUTHEAST.
BETTER CHANCES FOR SHOWERS AND STORMS WILL COME IN ON FRIDAY
ACROSS SOUTHEAST KENTUCKY...BUT CHANCES WILL PROBABLY BE HIGHLY
DEPENDENT ON LOCAL BOUNDARIES AND PREVIOUS CONVECTION. THUS...WILL
GO WITH A GENERAL SLIGHT CHANCE OF THUNDER FOR FRIDAY AFTERNOON
ACROSS THE SOUTHEAST PORTION OF THE AREA. WILL KEEP HIGHS FAIRLY
CLOSE TO WHAT WE HAVE SEEN LATELY IN THE UPPER 80S TODAY AND
FRIDAY WITH LOWS IN THE 60S TONIGHT.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 346 AM EDT THU SEP 3 2015
THE UPPER LEVEL PATTERN THROUGH THE EXTENDED WILL CONTINUE TO
FEATURE AN UPPER LEVEL RIDGE OVER THE EASTERN CONUS. BY MONDAY
THOUGH...THE PATTERN BEGINS TO SHIFT AS THE RIDGE SHIFTS EAST AND
A STRONG TROUGH MOVES ACROSS THE UPPER PLAINS. THIS WILL BRING A
SIGNIFICANT SHIFT IN THE PATTERN. MODELS HAVE BEEN HINTING AT THIS
CHANGE FOR THE PAST FEW RUNS.
CLOSER TO THE SURFACE...UNDERNEATH THE RIDGE...THE AREA HAS BEEN
UNDER WARM AND UNSTABLE CONDITIONS EACH AFTERNOON WITH WEAK UPPER
LEVEL SUPPORT CAUSING SOME AFTERNOON CONVECTION EACH DAY. WARM AND
MOIST MAINLY WEAK SOUTHERLY FLOW CONTINUES THROUGH MONDAY WITH
MORNING FOG GIVING WAY TO SLIGHT TO LOW CHANCE POPS EACH
AFTERNOON. THIS DIURNAL TREND CONTINUES TILL MONDAY NIGHT INTO
TUESDAY WHEN THE MENTIONED UPPER TROUGH DRAGS A COLD FRONT THROUGH
THE AREA WITH A MORE PRONOUNCED SURFACE GRADIENT AND FORCING FOR
CONVECTION AND A BETTER CHANCE OF PRECIP NOT SEEN IN DAYS. AT
THIS TIME...MODELS ARE SLOWLY TRENDING WEAKER WITH THIS FRONT SO
HAVE GONE SLIGHTLY UNDER THE ALL MODEL BLEND SOLUTION BUT THIS
FEATURE STILL IS THE LARGEST CHANGE IN THE PATTERN YET. WENT WITH
LOW CHANCE POPS INTO WEDNESDAY AS THIS FEATURE MOVES THROUGH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 214 PM EDT THU SEP 3 2015
MAINLY VFR CONDITIONS WILL HOLD THROUGH 06Z...WITH THE EXCEPTION
OF WHERE ISOLATED CONVECTION CAN TRACK...WHICH WOULD LIKELY YIELD
SOME TEMPORARY MVFR OR WORSE CONDITIONS. GIVEN THE LIMITED AREAL
COVERAGE...HAVE ONLY INCLUDED VCSH OR VCTS EAST OF I-75.
CONVECTION WILL DIE OFF TOWARDS THIS EVENING...WITH FOG BECOMING
THE MAIN CONCERN ONCE AGAIN. HAVE MIRRORED VISIBILITIES AND
CEILINGS THAT WERE SEEN THIS MORNING AT THE TAF SITES...WITH THE
MAJORITY OF LOCATIONS LIKELY GOING DOWN HARD FOR A TIME BETWEEN 08
AND 12Z ONCE AGAIN. FOG WILL BURN OFF BETWEEN 12 AND 13Z...WITH A
REPEAT OF ISOLATED CONVECTION THREATENING BY FRIDAY AFTERNOON.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEOGERIAN
SHORT TERM...KAS
LONG TERM...SHALLENBERGER
AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1221 PM CDT THU SEP 3 2015
.UPDATE...
Issued at 1220 PM CDT THU SEP 3 2015
The AVIATION section has been updated for the 18Z TAF issuance.
&&
.SHORT TERM...(Today through Saturday)
Issued at 327 AM CDT THU SEP 3 2015
The 00Z models try to pinch the upper ridge from the east Friday
into Saturday, which leads to a little bit more pronounced surface
ridging by Saturday. The models are spitting out QPF just
northeast of our region, especially Friday night, but MOS PoPs are
mostly single digits. Won`t be surprised if we end up with some
PoPs Friday night or Saturday, but for now will just mention it
here and keep the forecast dry, and in line with neighboring
offices.
A literal handful of showers and one brief thunderstorm developed
across the forecast area yesterday afternoon. They were short-
lived, and with one exception, did not produce lightning. The 00Z
ARW and NMM WRF runs both generate some isolated convection across
the region this afternoon, and the latest HRRR shows some isolated
weak showers. With that support, will play the persistence card and
add isolated showers and storms to all but the far northwest and
western fringes of the area this afternoon. Will wait and see
what happens this afternoon before considering it for Friday
afternoon.
Temperatures climbed toward the warmer MAV/EC guidance yesterday
afternoon, so will continue to go that way with high temperatures
today and Friday. The 00Z MAV has 97 for Paducah Friday, but that
seems a bit spurious compared to surrounding MOS sites. Saturday
is a bit less clear cut, with the upper ridge weakening and
indications of a minor surge of surface high pressure over the
Evansville Tri State.
Stayed on the warm side of guidance Saturday over the Tri State,
but that does result in a couple of degrees of cooling from
Friday`s levels. Outside of the Tri State, Saturday could be just
as warm as Friday. The humidity is nothing like we had mid-summer,
but it could be just enough to allow heat indices to approach 100
in a few locations each afternoon.
Low temperatures tonight will be similar to this morning`s lows,
which are a bit lower than the consensus of guidance in most
locations. Lows Friday night may be closer to the consensus with
more wind expected.
.LONG TERM...(Saturday Night through Wednesday)
Issued at 327 AM CDT THU SEP 3 2015
The deterministic runs of the med range models have been somewhat
unstable of late, and the latest GFS 500 mb height spaghetti pattern
shows significantly increased chaos by Tue (Day 6), though the
latest GFS/ECMWF ensemble means appear quite similar overall. This
will affect confidence in the latter period forecast, regarding
impulses of energy in the nrn stream which may or may not produce a
secondary sfc front in our region.
Early in the extended period, the PAH forecast area will be affected
by an amplified srn stream pattern, with ridging aloft west of the
MS River and troffing over the Atlantic seaboard. Meanwhile, by Mon,
a cold front is progged to impinge on the ridge over our region.
There might be enough lift to produce a few showers and tstms in the
nwrn half of our region Mon afternoon, perhaps progressing a bit
farther sewd Mon night. The latest ECMWF appears to break down the
ridge more than the GFS by Tue, and is therefore more generous with
its QPF into Wed. For now, we downplayed PoPs a bit for Mon/Mon
night because of the lingering mid/upper ridge, then went generally
with the model initialization blend after that, which provided no
more than 40% PoPs for any 12 hour period. At this time, it appears
that model consensus and HPC point toward a bona fide sfc fropa at
the very end of the present Day 7 (Wed).
Expect above average temps through the extended period, slowly
decreasing by Day 7 to near seasonable levels.
&&
.AVIATION...
Issued at 1221 PM CDT THU SEP 3 2015
A few isolated showers or thunderstorms will be possible again across
the region this afternoon, but the coverage is expected to be too
sparse to mention in any of the TAFs. Otherwise, the only concern
to aviaton is MVFR fog potential at all terminals late tonight.
Like the last few nights, the fog, if it develops, will burn off
by around 14Z. Cu should then start developing soon after with
only isolated chances for convection.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS JACKSON KY
1214 PM EDT THU SEP 3 2015
.UPDATE...
ISSUED AT 1214 PM EDT THU SEP 3 2015
A FEW SHORT-LIVED SHOWERS MANAGED TO DEVELOP ACROSS PORTIONS OF
EASTERN PIKE COUNTY EARLIER...HOWEVER THESE HAVE SINCE DISSIPATED.
THE CU FIELD HAS BEEN MORE PREVALENT IN THE EAST SO FAR AND THE
LATEST HRRR MODEL OUTPUT CONTINUES TO SUGGEST THE BETTER POTENTIAL
FOR ANY ISOLATED ACTIVITY FOR THOSE LOCATIONS. DID GO AHEAD AND
ADD THUNDER FOR TODAY GIVEN THE MODERATELY STEEP LOW LEVEL LAPSE
RATES TO DEVELOP DURING PEAK HEATING. HIGHS TODAY LOOK ON
TARGET...WITH MOST LOCATIONS REACHING AROUND THE 90 DEGREE MARK.
UPDATE ISSUED AT 736 AM EDT THU SEP 3 2015
NO UPDATE THIS MORNING AS FORECAST IS ON TRACK. LOTS OF VALLEY FOG
OUT THERE SHOULD AND IT SHOULD BE BURNING OFF OVER THE NEXT FEW
HOURS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 257 AM EDT THU SEP 3 2015
NO PATTERN CHANGE EXPECTED THROUGH FRIDAY. THIS WILL MEAN A
CONTINUATION OF UNSEASONABLY WARM AND HUMID CONDITIONS THROUGH THE
END OF THE WEEK. A WEAK UPPER LEVEL TROUGH WILL CONTINUE TO
PRODUCE A MEAGER CHANCE OF A FEW AFTERNOON SHOWERS OR STORMS TODAY
AND AGAIN FRIDAY. HOWEVER...AS FAR AS TODAY GOES...HI RES MODELS
ARE INDICATING THAT WE MAY BE IN A HOLE WITH REGARDS TO CONVECTION
TODAY...KEEPING EVERYTHING FARTHER EAST. THERE DOES APPEAR TO BE A
WAVE IN THE FLOW TO OUR NORTHEAST...BUT REALLY SHOULD CLIP OUR
AREA. THUS...WILL DOWNPLAY PRECIPITATION CHANCES TODAY...JUST
GOING WITH A SLIGHT CHANCE OF A SHOWER IN THE FAR EAST/SOUTHEAST.
BETTER CHANCES FOR SHOWERS AND STORMS WILL COME IN ON FRIDAY
ACROSS SOUTHEAST KENTUCKY...BUT CHANCES WILL PROBABLY BE HIGHLY
DEPENDENT ON LOCAL BOUNDARIES AND PREVIOUS CONVECTION. THUS...WILL
GO WITH A GENERAL SLIGHT CHANCE OF THUNDER FOR FRIDAY AFTERNOON
ACROSS THE SOUTHEAST PORTION OF THE AREA. WILL KEEP HIGHS FAIRLY
CLOSE TO WHAT WE HAVE SEEN LATELY IN THE UPPER 80S TODAY AND
FRIDAY WITH LOWS IN THE 60S TONIGHT.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 346 AM EDT THU SEP 3 2015
THE UPPER LEVEL PATTERN THROUGH THE EXTENDED WILL CONTINUE TO
FEATURE AN UPPER LEVEL RIDGE OVER THE EASTERN CONUS. BY MONDAY
THOUGH...THE PATTERN BEGINS TO SHIFT AS THE RIDGE SHIFTS EAST AND
A STRONG TROUGH MOVES ACROSS THE UPPER PLAINS. THIS WILL BRING A
SIGNIFICANT SHIFT IN THE PATTERN. MODELS HAVE BEEN HINTING AT THIS
CHANGE FOR THE PAST FEW RUNS.
CLOSER TO THE SURFACE...UNDERNEATH THE RIDGE...THE AREA HAS BEEN
UNDER WARM AND UNSTABLE CONDITIONS EACH AFTERNOON WITH WEAK UPPER
LEVEL SUPPORT CAUSING SOME AFTERNOON CONVECTION EACH DAY. WARM AND
MOIST MAINLY WEAK SOUTHERLY FLOW CONTINUES THROUGH MONDAY WITH
MORNING FOG GIVING WAY TO SLIGHT TO LOW CHANCE POPS EACH
AFTERNOON. THIS DIURNAL TREND CONTINUES TILL MONDAY NIGHT INTO
TUESDAY WHEN THE MENTIONED UPPER TROUGH DRAGS A COLD FRONT THROUGH
THE AREA WITH A MORE PRONOUNCED SURFACE GRADIENT AND FORCING FOR
CONVECTION AND A BETTER CHANCE OF PRECIP NOT SEEN IN DAYS. AT
THIS TIME...MODELS ARE SLOWLY TRENDING WEAKER WITH THIS FRONT SO
HAVE GONE SLIGHTLY UNDER THE ALL MODEL BLEND SOLUTION BUT THIS
FEATURE STILL IS THE LARGEST CHANGE IN THE PATTERN YET. WENT WITH
LOW CHANCE POPS INTO WEDNESDAY AS THIS FEATURE MOVES THROUGH.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 736 AM EDT THU SEP 3 2015
ANOTHER TYPICAL EASTERN KENTUCKY MORNING WITH MORE VALLEY FOG.
THIS FOG WILL BURN OFF OVER THE NEXT HOUR TO TWO HOURS. THIS WILL
BRING A RETURN TO VFR CONDITIONS BY MID MORNING. SOME SCATTERED
CU WILL DEVELOP TOMORROW AFTERNOON...BUT CONDITIONS SHOULD STAY
VFR THROUGH THE EVENING. ANOTHER ROUND OF VALLEY FOG IS EXPECTED
LATE TONIGHT AND WILL BRING VISIBILITIES AND CEILINGS DOWN AT THE
TAF SITES ONCE MORE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEOGERIAN
SHORT TERM...KAS
LONG TERM...SHALLENBERGER
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS PADUCAH KY
641 AM CDT THU SEP 3 2015
.UPDATE...
Issued at 641 AM CDT THU SEP 3 2015
The AVIATION section has been updated for the 12Z TAF issuance.
&&
.SHORT TERM...(Today through Saturday)
Issued at 327 AM CDT THU SEP 3 2015
The 00Z models try to pinch the upper ridge from the east Friday
into Saturday, which leads to a little bit more pronounced surface
ridging by Saturday. The models are spitting out QPF just
northeast of our region, especially Friday night, but MOS PoPs are
mostly single digits. Won`t be surprised if we end up with some
PoPs Friday night or Saturday, but for now will just mention it
here and keep the forecast dry, and in line with neighboring
offices.
A literal handful of showers and one brief thunderstorm developed
across the forecast area yesterday afternoon. They were short-
lived, and with one exception, did not produce lightning. The 00Z
ARW and NMM WRF runs both generate some isolated convection across
the region this afternoon, and the latest HRRR shows some isolated
weak showers. With that support, will play the persistence card and
add isolated showers and storms to all but the far northwest and
western fringes of the area this afternoon. Will wait and see
what happens this afternoon before considering it for Friday
afternoon.
Temperatures climbed toward the warmer MAV/EC guidance yesterday
afternoon, so will continue to go that way with high temperatures
today and Friday. The 00Z MAV has 97 for Paducah Friday, but that
seems a bit spurious compared to surrounding MOS sites. Saturday
is a bit less clear cut, with the upper ridge weakening and
indications of a minor surge of surface high pressure over the
Evansville Tri State.
Stayed on the warm side of guidance Saturday over the Tri State,
but that does result in a couple of degrees of cooling from
Friday`s levels. Outside of the Tri State, Saturday could be just
as warm as Friday. The humidity is nothing like we had mid-summer,
but it could be just enough to allow heat indices to approach 100
in a few locations each afternoon.
Low temperatures tonight will be similar to this morning`s lows,
which are a bit lower than the consensus of guidance in most
locations. Lows Friday night may be closer to the consensus with
more wind expected.
.LONG TERM...(Saturday Night through Wednesday)
Issued at 327 AM CDT THU SEP 3 2015
The deterministic runs of the med range models have been somewhat
unstable of late, and the latest GFS 500 mb height spaghetti pattern
shows significantly increased chaos by Tue (Day 6), though the
latest GFS/ECMWF ensemble means appear quite similar overall. This
will affect confidence in the latter period forecast, regarding
impulses of energy in the nrn stream which may or may not produce a
secondary sfc front in our region.
Early in the extended period, the PAH forecast area will be affected
by an amplified srn stream pattern, with ridging aloft west of the
MS River and troffing over the Atlantic seaboard. Meanwhile, by Mon,
a cold front is progged to impinge on the ridge over our region.
There might be enough lift to produce a few showers and tstms in the
nwrn half of our region Mon afternoon, perhaps progressing a bit
farther sewd Mon night. The latest ECMWF appears to break down the
ridge more than the GFS by Tue, and is therefore more generous with
its QPF into Wed. For now, we downplayed PoPs a bit for Mon/Mon
night because of the lingering mid/upper ridge, then went generally
with the model initialization blend after that, which provided no
more than 40% PoPs for any 12 hour period. At this time, it appears
that model consensus and HPC point toward a bona fide sfc fropa at
the very end of the present Day 7 (Wed).
Expect above average temps through the extended period, slowly
decreasing by Day 7 to near seasonable levels.
&&
.AVIATION...
Issued at 641 AM CDT THU SEP 3 2015
A few isolated showers or thunderstorms will be possible again across
the region this afternoon, but the coverage is expected to be too
sparse to mention in any of the TAFs. Otherwise, the only concern
to aviaton is more fog potential at all terminals late tonight.
Guidance is too pessimistic at KCGI, and figure that persistence
should be pretty close. Used it as a guide in mentioning
prevailing MVFR fog at all sites in the last few hours of the
forecast.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...DRS
SHORT TERM...DRS
LONG TERM...DB
AVIATION...DRS
AREA FORECAST DISCUSSION
NWS PADUCAH KY
327 AM CDT THU SEP 3 2015
.SHORT TERM...(Today through Saturday)
Issued at 327 AM CDT THU SEP 3 2015
The 00Z models try to pinch the upper ridge from the east Friday
into Saturday, which leads to a little bit more pronounced surface
ridging by Saturday. The models are spitting out QPF just
northeast of our region, especially Friday night, but MOS PoPs are
mostly single digits. Won`t be surprised if we end up with some
PoPs Friday night or Saturday, but for now will just mention it
here and keep the forecast dry, and in line with neighboring
offices.
A literal handful of showers and one brief thunderstorm developed
across the forecast area yesterday afternoon. They were short-
lived, and with one exception, did not produce lightning. The 00Z
ARW and NMM WRF runs both generate some isolated convection across
the region this afternoon, and the latest HRRR shows some isolated
weak showers. With that support, will play the persistence card and
add isolated showers and storms to all but the far northwest and
western fringes of the area this afternoon. Will wait and see
what happens this afternoon before considering it for Friday
afternoon.
Temperatures climbed toward the warmer MAV/EC guidance yesterday
afternoon, so will continue to go that way with high temperatures
today and Friday. The 00Z MAV has 97 for Paducah Friday, but that
seems a bit spurious compared to surrounding MOS sites. Saturday
is a bit less clear cut, with the upper ridge weakening and
indications of a minor surge of surface high pressure over the
Evansville Tri State.
Stayed on the warm side of guidance Saturday over the Tri State,
but that does result in a couple of degrees of cooling from
Friday`s levels. Outside of the Tri State, Saturday could be just
as warm as Friday. The humidity is nothing like we had mid-summer,
but it could be just enough to allow heat indices to approach 100
in a few locations each afternoon.
Low temperatures tonight will be similar to this morning`s lows,
which are a bit lower than the consensus of guidance in most
locations. Lows Friday night may be closer to the consensus with
more wind expected.
.LONG TERM...(Saturday Night through Wednesday)
Issued at 327 AM CDT THU SEP 3 2015
The deterministic runs of the med range models have been somewhat
unstable of late, and the latest GFS 500 mb height spaghetti pattern
shows significantly increased chaos by Tue (Day 6), though the
latest GFS/ECMWF ensemble means appear quite similar overall. This
will affect confidence in the latter period forecast, regarding
impulses of energy in the nrn stream which may or may not produce a
secondary sfc front in our region.
Early in the extended period, the PAH forecast area will be affected
by an amplified srn stream pattern, with ridging aloft west of the
MS River and troffing over the Atlantic seaboard. Meanwhile, by Mon,
a cold front is progged to impinge on the ridge over our region.
There might be enough lift to produce a few showers and tstms in the
nwrn half of our region Mon afternoon, perhaps progressing a bit
farther sewd Mon night. The latest ECMWF appears to break down the
ridge more than the GFS by Tue, and is therefore more generous with
its QPF into Wed. For now, we downplayed PoPs a bit for Mon/Mon
night because of the lingering mid/upper ridge, then went generally
with the model initialization blend after that, which provided no
more than 40% PoPs for any 12 hour period. At this time, it appears
that model consensus and HPC point toward a bona fide sfc fropa at
the very end of the present Day 7 (Wed).
Expect above average temps through the extended period, slowly
decreasing by Day 7 to near seasonable levels.
&&
.AVIATION...
Issued at 1152 PM CDT WED SEP 2 2015
Little change from 00z Thursday TAF issuance. Main adjustment was
to reflect recent climatological visibility trends at KCGI, KEVV,
and KOWB. The lower visibility fog should be partial in coverage
and consist primarily of ground fog near each TAF site.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
SHORT TERM...DRS
LONG TERM...DB
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1152 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 isn`t 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 1152 PM CDT WED SEP 2 2015
Little change from 00z Thursday TAF issuance. Main adjustment was
to reflect recent climatological visibility trends at KCGI, KEVV,
and KOWB. The lower visibility fog should be partial in coverage
and consist primarily of ground fog near each TAF site.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1050 PM EDT FRI SEP 4 2015
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 323 PM EDT FRI SEP 4 2015
A WEAK LOW PRESSURE AREA WILL HELP TRIGGER SHOWERS AND POSSIBLY A
THUNDERSTORM THIS EVENING INTO EARLY TONIGHT OVER NORTHERN LOWER
MICHIGAN AS IT DRIFTS NORTHWARD. BEHIND IT...WARM AND HUMID AIR WILL
RETURN FROM THE SOUTH WITH SLIGHT CHANCES FOR SHOWERS AND
THUNDERSTORMS. SUNDAY WILL BE HOT AND DRY WITH HIGHS NEAR 90. THIS
WILL BE FOLLOWED BY A WET PERIOD LASTING LABOR DAY THROUGH TUESDAY
AS A COLD FRONT PASSES. BEHIND THIS FRONT...THE LATTER HALF OF THE
WORK WEEK WILL FEATURE MUCH DRIER CONDITIONS AND HIGHS IN THE LOW TO
MID 70S.
&&
.UPDATE...
ISSUED AT 1049 PM EDT FRI SEP 4 2015
DID NOT MAKE BIG CHANGES TO THE FORECAST...BUT DID ADD AREAS OF
FOG WORDING VERSUS PATCHY AS WE SHOULD SEE FOG IN MANY AREAS.
MASON AND CHARLOTTE HAVE ALREADY HAD VISIBILITIES DIP TO AROUND 1
MILE. EXPECTING FOG TO BECOME MORE PREVALENT THROUGH THE NIGHT
GIVEN LIGHT WINDS AND A MOIST AIR MASS.
AS FOR PRECIP CHANCES...FEEL WE MAY SEE ISOLATED TO SCATTERED
SHOWERS AND STORMS DEVELOP NEAR AND ESPECIALLY SOUTH OF INTERSTATE
96. THE RAP13 MODEL AS WELL AS THE NAM ARE INDICATING A WEAK LLJ
DEVELOPING ALONG WITH SOME MODEST 850MB MOISTURE TRANSPORT. THE
SOUTHERN CWA WILL BE NEAR A WEAK 850MB WARM FRONTAL FEATURE THAT
CAN BE SEEN IN THE 850MB DEW POINT FIELDS. HAVE ISOLATED SHOWERS
POSSIBLE NORTH WITH ISOLATED SHOWERS AND STORMS TO THE SOUTH.
LATEST RUN OF THE HRRR HAS THE SHOWERS AND STORMS DEVELOPING
TOWARD INTERSTATE 94 AROUND DAYBREAK. OTHER CONVECTION ALLOWING
MODELS HAVE ACTIVITY DEVELOPING SOONER IN THE NIGHT. NOTHING
STRONG...BUT WE WILL BE KEEPING AN EYE ON THE RADAR OVERNIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 323 PM EDT FRI SEP 4 2015
CONTINUED TO TRIM RAIN CHANCES FOR THIS EVENING AND EARLY TONIGHT AS
LOW LEVEL FORCING CONTINUES WITH SURFACE LOW DRIFTING NORTH. SOME
CONVECTION ALLOWING MODELS SUGGEST SHOWERS AND THUNDERSTORMS WILL
DEVELOP OR SPREAD NORTH TOWARDS THE I-94 CORRIDOR SATURDAY
MORNING...POSSIBLY ASSOCIATED WITH REMNANTS OF THE ONGOING
CONVECTION ACROSS NORTHERN INDIANA. ALSO EXPECT AT LEAST PATCHY FOG
AGAIN SATURDAY MORNING...BUT THIS WILL AGAIN BE TRICKY GIVEN THE
POTENTIAL FOR LOW CLOUDS.
SUNDAY STILL LOOKS HOT WITH HIGHS NEAR 90. ALSO STILL EXPECT IT TO
BE DRY PER GFS FORECAST SOUNDINGS...BUT AS NOTED IN THE PREVIOUS
DISCUSSION...LAKE BREEZE SHOWERS OR STORMS ARE NOT OUT OF THE
QUESTION AND THIS WILL HAVE TO BE WATCHED.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 323 PM EDT FRI SEP 4 2015
WE WILL SEE A BIG PATTERN CHANGE IN THE EXTENDED AS UPPER RIDGING AT
THE BEGINNING OF THE PERIOD IS REPLACED BY UPPER TROUGHING BY THE
END. IN BETWEEN WE ARE DEALING WITH A SLOW MOVING FRONT THAT SHOULD
BRING PERIODS OF RAIN...POSSIBLY HEAVY...FROM LATE MONDAY INTO EARLY
WEDNESDAY.
FORECAST UNCERTAINTY IS NOT SO MUCH WITH THE TIMING OF THAT INITIAL
FRONT BUT WITH THE HANDLING OF A SECONDARY FRONT THAT FOLLOWS AS THE
UPPER TROUGH DEEPENS. THE SPLIT BETWEEN THE SOLUTIONS VARIES FROM A
MUCH QUICKER GFS SOLUTION THAT BRINGS IT IN WEDNESDAY NIGHT AND
THURSDAY TO THE EURO WHICH HOLDS IF OFF UNTIL FRIDAY. DECIDED TO GO
TOWARDS THE LATER SOLUTION...SO KEPT THURSDAY DRY FOR NOW.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 858 PM EDT FRI SEP 4 2015
LOWER CLOUD HAS LIFTED AND SCATTERED OUT ACROSS MOST OF THE AREA
AT 00Z-01Z. CURRENT THINKING THOUGH IS THAT IT MAY REDEVELOP
OVERNIGHT ALONG A WEAK WARM FRONTAL FEATURE ALOFT MOVING INTO
SOUTHWEST LOWER MI. EXPECTING SOME LIGHT FOG TO DEVELOP (MVFR) IN
THE 03Z-06Z TIME FRAME WITH 2500FT CEILINGS DEVELOPING BETWEEN 08Z
AND 11Z. THERE MAY BE A FEW SHOWERS AND STORMS THAT OCCUR AFTER
06Z AND BROUGHT A VCTS GROUP INTO THE WESTERN TAF SITES OF
KMKG...KGRR AND KAZO LATE TONIGHT AND SATURDAY MORNING.
THE FOG AND MVFR CEILINGS SHOULD LIFT THROUGH THE COURSE OF
SATURDAY MORNING WITH VFR CONDITIONS EXPECTED THEREAFTER. STORMS
MAY REDEVELOP FOR KAZO...KBTL...KLAN AND KJXN SATURDAY AFTERNOON.
&&
.MARINE...
ISSUED AT 323 PM EDT FRI SEP 4 2015
WINDS AND WAVES EXPECTED TO STAY LOW THROUGH SATURDAY NIGHT WITH A
SLIGHT UPTICK SUNDAY AHEAD OF AN APPROACHING COLD FRONT. LABOR DAY
COULD FEATURE WAVES OF 3 OR MORE FEET NORTH OF MUSKEGON AS WINDS
FROM THE SOUTH PERSIST AND CONTINUE TO INCREASE.
&&
.HYDROLOGY...
ISSUED AT 1054 AM EDT FRI SEP 4 2015
NO CONCERNS EXIST IN THE NEAR TERM. QUESTIONS ARISE GOING INTO NEXT
WEEK AS A BOUNDARY DRAPES ITSELF SOMEWHERE THROUGH OR NEAR THE GREAT
LAKES REGION.
AREA RIVERS HAVE RESPONDED PRETTY WELL TO YESTERDAYS RAINFALL.
LOCALIZED TOTALS OF MORE THAN TWO INCHES RESULTED IN DECENT UPWARD
TRENDS AT A FEW FORECAST POINTS. MOST NOTABLE IS SYCAMORE CREEK AT
HOLT...WHICH HAS LEVELED OFF ABOUT A FOOT BELOW ADVISORY CRITERIA.
PROVIDED THAT ADDITIONAL RAINFALL IS LIMITED...HOLT SHOULD CONTINUE
ITS DOWNWARD TREND. OTHER SITES HAVE ALSO LEVELED OFF AND RESPONSES
HAVE BEEN MINOR.
RAINFALL THROUGH THE WEEKEND IS EXPECTED TO BE SCATTERED WITH
LOCALIZED HEAVY RAIN POSSIBLE IN OR AROUND THUNDERSTORMS. CONDITIONS
ARE NOT FAVORABLE FOR WIDESPREAD HEAVY RAIN. A PATTERN CHANGE WILL
TAKE PLACE NEXT WEEK AND ITS ASSOCIATED BOUNDARY LOOKS TO BE MOVING
SLOWLY. DIFFERENCES IN LONG RANGE MODELS PUT A CAP ON ANY HIGH
CONFIDENCE. HOWEVER...PWATS ARE 1.5-2.0 INCHES AND THE SLOW
PROGRESSION OF THE BOUNDARY COULD RESULT IN PRETTY DECENT RAINFALL
TOTALS MONDAY THROUGH WEDNESDAY. THE SETUP MAY SUGGEST MORE THAN AN
INCH...WITH AREAS EXCEEDING A COUPLE OF INCHES IF STORMS ARE SLOW
MOVERS. THIS WILL LIKELY BE THE FOCUS HYDRO-WISE OVER THE NEXT
FEW DAYS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...DUKE
SYNOPSIS...TJT
SHORT TERM...TJT
LONG TERM...OSTUNO
AVIATION...DUKE
HYDROLOGY...JAM
MARINE...TJT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
741 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 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 740 PM EDT FRI SEP 4 2015
VFR CONDITIONS WILL PREVAIL AT KIWD/KCMX/KSAW THRU THE EVENING HRS.
OVERNIGHT...AN INCREASE IN MOISTURE FROM THE SE SHOULD RESULT IN FOG
AND SOME STRATUS DEVELOPMENT...MAINLY AT KSAW WHICH IS CLOSER TO THE
ARRIVING MOISTURE POOL AND DUE TO BETTER UPSLOPING. AT KSAW...MVFR
CONDITIONS WILL DEVELOP OVERNIGHT WITH THE POTENTIAL OF A FEW HRS OF
LIFR CONDITIONS AROUND SUNRISE. A PERIOD OF MVFR VIS IS EXPECTED AT
KIWD/KCMX AROUND SUNRISE. FOG/STRATUS WILL BURN OFF IN THE
MORNING...RESULTING IN VFR CONDITIONS PREVAILING FROM MID MORNING
SAT THRU THE END OF THE FCST PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 318 PM EDT FRI SEP 4 2015
EAST TO NORTHEAST WINDS OF 10-15KT WILL CONTINUE UNTIL THE NEXT
CHANCE FOR WINDS GREATER THAN 20KT COMES ON MONDAY BEHIND A COLD
FRONT. FOG WILL CONTINUE TO BE PATCHY ACROSS THE LAKE UNTIL THE COLD
FRONT MOVES THROUGH.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...TITUS
LONG TERM...JLB
AVIATION...ROLFSON
MARINE...TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
357 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 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 137 PM EDT THU SEP 3 2015
EXPECT VFR CONDITIONS THROUGH THIS EVENING. CLEAR SKIES AND LIGHT
WINDS WILL LIKELY CAUSE IFR CONDITIONS ONCE AGAIN LATER TONIGHT INTO
FRIDAY MORNING...MAINLY AT KIWD/KSAW WHILE MVFR VSBY IS EXPECTED AT
KCMX.
&&
.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...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
317 PM EDT THU SEP 3 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 412 AM EDT THU SEP 3 2015
THE RAIN OVER THE SOUTHERN AND EASTERN PART OF THE FORECAST AREA
FINALLY SEEMS TO BE MOVING OUT OF THE AREA AS THE UPPER SHORT WAVE
MOVES EAST. THE BIG PROBLEM THIS MORNING IS ACTUALLY DENSE FOG
ACROSS THE WESTERN PART OF THE FORECAST AREA WHERE IT HAS CLEARED
OUT WITH SUFFICIENT LOW LEVEL MOISTURE FROM RAINFALL OVER THE PAST
24 HR. MOST OF THE WESTERN TIER OF COUNTIES HAVE VSBYS LESS THAN ONE
QUARTER OF A MILE AND AS SUCH HAVE OPTED TO GO WITH A DENSE FOG
ADVISORY FOR THIS AREA UNTIL 14Z.
OTHERWISE...AS THE UPPER SHORT WAVE SLOWLY MOVES EAST THIS
MORNING...EXPECT ANY REMAINING SHOWERS TO MOVE OUT OF THE AREA AS
WELL. THE RAP SUGGESTS THAT CYCLONIC FLOW WILL PERSIST THROUGH THE
DAY ACROSS THE EAST. THIS COMBINED WITH LAKE BREEZE CONVERGENCE
ACROSS THE EAST IMPLIES AT LEAST A SLIGHT CHANCE OF SHOWERS THIS
AFTERNOON ACROSS THE FAR EAST. NOT TOO EXCITED ABOUT THUNDERSTORM
CHANCES AS LOCAL RESEARCH SUGGESTS VERY MIMINAL THUNDERSTORM
DEVELOPMENT WITH NORTHERLY MID LEVEL FLOW. ACROSS THE REMAINDER OF
THE AREA...MINIMAL MLCAPE VALUES OF LESS THAN 300 J/KG PER THE
RAP...DRY AIR ASSOCIATED WITH THE HIGH PRES AND BUILDING HEIGHTS
SHOULD PRECLUDE ANY SHOWER/THUNDERSTORM DEVELOPMENT. DESPITE THE
NORTH-NORTHEAST FLOW...IT WILL STILL REMAIN MILD AND RATHER STICKY
WITH HIGHS IN THE UPPER 70S/LOWER 80S...STILL ABOVE NORMAL FOR EARLY
SEPTEMBER.
WITH HIGH PRESSURE IN CONTROL...IT SHOULD BE A QUIET NIGHT TONIGHT.
CANNOT RULE OUT MORE FOG DEVELOPMENT ACROSS THE INTERIOR WITH LIGHT
WINDS AND CLEAR SKIES. TEMPS SHOULD DROP INTO THE UPPER 50S/LOWER
60S.
.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 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 137 PM EDT THU SEP 3 2015
EXPECT VFR CONDITIONS THROUGH THIS EVENING. CLEAR SKIES AND LIGHT
WINDS WILL LIKELY CAUSE IFR CONDITIONS ONCE AGAIN LATER TONIGHT INTO
FRIDAY MORNING...MAINLY AT KIWD/KSAW WHILE MVFR VSBY IS EXPECTED AT
KCMX.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 412 AM EDT THU SEP 3 2015
DENSE FOG HAS DEVELOPED ACROSS THE WESTERN HALF OF THE
LAKE...ESPECIALLY OVER AREAS THAT SAW RAIN YESTERDAY. AS SUCH...HAVE
ISSUED A DENSE FOG ADVY FOR THE ENTIRE WEST HALF OF THE LAKE THROUGH
EARLY THIS AFTERNOON. 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...MRD
LONG TERM...TITUS
AVIATION...JLB
MARINE...MRD
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
217 PM EDT THU SEP 3 2015
.AVIATION...
DEEPER MOISTURE AXIS AND THERMAL ADVECTION SUPPORT OCCURRING ON
THE SOUTHEAST FORWARD FLANK OF MCS IS LEADING TO WIDESPREAD RAIN
AND THUNDERSTORM ACTIVITY THIS AFTERNOON. CONFIDENCE IS HIGH IN
CONTINUED ACTIVITY FOR THE NEXT 3-6 HOURS WITH INCREASING
UNCERTAINTY FOR TONIGHT. A STALLING OUT OF PARENT FORCING ALOFT DOES
SUPPORT THE POTENTIAL THAT SHOWER AND THUNDERSTORMS COULD AFFECT
THE AREA THROUGH MUCH OF TONIGHT. HIGH LOW LEVEL MOISTURE CONTENT
AND WET SOIL CONDITIONS SUPPORTS FOG DEVELOPMENT LATE.
POSSIBILITY EXISTS FOR ONE OR MORE TERMINALS TO DROP INTO LIFR
DURING THE EARLY MORNING PERIOD...CONFIDENCE TOO LOW YET TO
INCLUDE BUT WILL HIGHLIGHT WITH IFR VSBY RESTRICTIONS.
FOR DTW...GREATEST POTENTIAL FOR THUNDERSTORMS CENTERED WITHIN THE
18Z-00Z WINDOW...UNCERTAINTY IS HIGH WITH REGARDS TO THUNDERSTORM
POTENTIAL 00-12Z.
//DTW THRESHOLD PROBABILITIES...
* MEDIUM FOR CIG AOB 5KFT THIS AFTERNOON AND EVENING
* HIGH FOR THUNDERSTORMS THIS AFTERNOON AND EVENING
&&
.PREV DISCUSSION...ISSUED 1239 PM EDT THU SEP 3 2015
UPDATE...
DUAL SHORTWAVES OVER THE WESTERN AND CENTRAL GREAT LAKES WILL
REMAIN THE SOLE FORCING MECHANISMS THROUGH THE NEXT 18 HOURS. THE
SMALL MCS IMPACTING LOWER MICHIGAN IS TIED TO THE FIRST LOWER
COLUMN PV ANOMALY...THE SECOND IS THE SHORTWAVE CIRCULATION THAT
IS NOW DROPPING INTO THE BACKSIDE OF THE GEOPOTENTIAL HEIGHT
WEAKNESS OVER FAR NORTHERN WISCONSIN. AT THE BIG PICTURE...LOWER
DELTA X SOLUTIONS/GLOBAL MODELS SUGGEST A PHASING OF THE TWO
SHORTWAVES AND A SUBSEQUENT STALLING OF THE COMBINED PV ANOMALY
LATE THIS AFTERNOON AND TONIGHT.
THE MCS THAT HAS BEEN PUSHING ACROSS THE NORTHERN CWA CONTINUES TO
MAKE SOME PROGRESS EASTWARD. A LINEAR EXTRAPOLATION OF REGIONAL Z
MOSAIC CONTINUES TO SUPPORT SOME SLIGHT SOUTHWARD DRIFT WITH TIME
ON THE TRACK OF THE MCS. THIS SOUTHWARD DRIFT SHOULD AT LEAST BE
PARTIALLY SUPPORTIVE BY ADDITIONAL OUTFLOW DEVELOPMENT ALONG THE
SOUTHERN FLANK. THERE HAS BEEN SOME MODEST...CONTINUED DEVELOPMENT
DURING THE PAST FEW HOURS. NWP GUIDANCE WITH A BULLISH HRRR AND
BOTH NAM/ECMWF SUPPORT BRING ADDITIONAL CONVECTIVE DEVELOPMENT FOR
ALL OF SOUTHEASTERN MICHIGAN DURING THE AFTERNOON HOURS. GIVEN THE
LACK OF AN AGGRESSIVE SOUTHERN PROGRESSION TO THE
STRATUS/CIRRUS/CU DECK EXPECTATIONS ARE FOR THE
INSTABILITY/BUOYANCY GRADIENT TO REMAIN DRAPED THROUGH FAR
SOUTHERN SECTIONS OF THE CWA. THE FORECAST IS SKEWED ON THE
AGGRESSIVE SIDE WITH RESPECT TO RAIN AND THUNDERSTORM ACTIVITY
THIS LATER THIS AFTERNOON AND EVENING. THERE DOES REMAIN A SLIVER
OF DOUBT THAT THUNDERSTORMS WILL FILL IN COMPLETELY ACROSS FAR
SOUTHERN LOWER MICHIGAN AND IMPACT DETROIT METRO DIRECTLY. STORM
BEHAVIOR TODAY IS EXPECTED TO REMAIN MORE OF A PULSE TYPE NATURE
WITH PERHAPS SOME EMBEDDED LINE TYPE FEATURES. THEREFORE...A LOW
END DAMAGING WIND GUST THREAT EXISTS THIS AFTERNOON AND WILL
PERHAPS BE A CIRCUMSTANCE OF CONSTRUCTIVE CELL MERGERS OR
PRECIPITATION LOADING EFFECTS.
A CONCERNING POTENTIAL WILL CONTINUE TO BE A HEAVY RAINFALL
THREAT...ESPECIALLY UNDER THE DIRECTION OF ADVERTISED PHASING AND
STALLING OUT OF PV MAX OVERHEAD. PWATS ARE AT APPROXIMATELY 1.8
INCHES. SOME SAMPLED RAINFALL RATES EARLIER OFF OF RADAR BASED
PRECIPITATION PRODUCT SUGGESTS 1.25 INCHES OF RAINFALL IS
POSSIBLE IN ROUGHLY 40 MINUTES. WILL BE MONITORING ACTIVITY THIS
AFTERNOON FOR ANY TRAINING OR STATIONARY BEHAVIOR OF THUNDERSTORMS.
PREV DISCUSSION...ISSUED 333 AM EDT THU SEP 3 2015
SHORT TERM...TODAY AND TONIGHT
ATTENTION OVER THE NEXT 24 TO 36 HOURS CENTERS ON THE INBOUND SLOWLY
MOVING MID LEVEL WAVE CURRENTLY CENTERED ACROSS THE LAKE MICHIGAN
CORRIDOR. LITTLE VARIATION IN THE UNDERLYING LOW LEVEL
THERMODYNAMIC PROFILE HEADING INTO TODAY...WITH SE MICHIGAN FIRMLY
ENTRENCHED WITHIN A MOISTURE RICH LOW LEVEL ENVIRONMENT /LOWER 70S
DEWPOINTS/. AS NOTED YESTERDAY...THIS WILL AGAIN TRANSLATE INTO
SUBSTANTIAL LOW LEVEL INSTABILITY (2500+ J/KG SBCAPE) WITHIN A VERY
STEEP LAPSE RATE ENVIRONMENT. INCREASING DPVA AND AN ACCOMPANYING POCKET
OF COOLER MID LEVEL TEMPERATURES WILL CONTRIBUTE AN ADDITIONAL
COMPONENT OF DESTABILIZATION AND MORE FOCUSED ASCENT FOR TODAY.
THIS ENVIRONMENT SEEMS CONDUCIVE FOR A MORE SIZABLE EXPANSION IN
CONVECTIVE COVERAGE LOCALLY...AND WORTHY OF A NUDGE UPWARD IN
POPS...PARTICULARLY FOR THE AFTERNOON/EVENING PERIODS. THE HIGH
MOISTURE CONTENT AND CORRESPONDING POTENTIAL FOR SIGNIFICANT
PRECIPITATION LOADING WITHIN THE DEEPEST CONVECTIVE CELLS WILL
AGAIN PRESENT THE POTENTIAL FOR STRONGER WIND GUSTS...WITH AT
LEAST AN OUTSIDE POSSIBILITY THAT AN ISOLATED STORM OR TWO CAN
GENERATE A PEAK GUST NEARING SEVERE LIMITS. SOLID HEAVY RAINFALL
THREAT GIVEN LIKELY LIMITED STORM MOTION WITHIN THIS HIGH CAPE
ENVIRONMENT. HIGHS TODAY A TOUCH LOWER WITH THE ENSUING EXPANSION
IN CONVECTION/CLOUD COVER LIKELY UNDERCUTTING THE HEATING
POTENTIAL SLIGHTLY. READINGS TOPPING OUT IN THE LOWER AND MIDDLE
80S...HEAT INDICES APPROACHING 90.
GRADUAL COOLING VIA DIABATIC PROCESSES AND ANY OUTFLOW WILL FAVOR A
DIMINISHING TREND TO EXISTING CONVECTIVE ACTIVITY BY EARLY TONIGHT.
HOWEVER THE UNDERLYING ENVIRONMENT WILL STILL REMAIN FAVORABLE FOR
ADDITIONAL ISOLATED-SCATTERED DEVELOPMENT THROUGHOUT THE NIGHT.
INCREASING POTENTIAL FOR FOG OVERNIGHT...MOIST NEAR SURFACE
ENVIRONMENT AUGMENTED BY THE RAINFALL AND WEAK GRADIENT. A CORRIDOR
OF DENSE FOG FOR THE EARLY MORNING COMMUTE NOT OUT OF THE QUESTION.
LONG TERM...
MULTIPLE UPPER WAVES UPSTREAM OVER UPPER MISSISSIPPI RIVER VALLEY
THIS MORNING...WHICH WILL CONSOLIDATE OVER THE WESTERN/CENTRAL GREAT
LAKES TONIGHT INTO FRIDAY...BUT THE EXACT POSITION OF THE DEVELOPED
MID LEVEL CIRCULATION/500 MB LOW IS QUESTION...AS 00Z NAM/GFS ARE
INDICATING A FARTHER SOUTH/WEST SOLUTION...NEAR CHICAGO...WHILE
EURO/CANADIAN REMAIN STEADFAST WITH 500 MB LOW FARTHER NORTH/EAST
OVER NORTHERN LOWER MICHIGAN. EITHER WAY...CHANCE POPS STILL SEEM
WARRANTED...EVEN WITH THE STRENGTHENING HIGH PRESSURE OVER EASTERN
CANADA (1025 MB)...AS THE LOW LEVEL SOUTHEAST/EAST FLOW WILL
INCREASE A BIT...BUT THERE ACTUALLY LOOKS TO BE MODEST MOISTURE
ADVECTION FROM WESTERN PA/LAKE ERIE. MLCAPES PROGGED TO INCREASE
INTO THE 500 TO 1500 J/KG RANGE DURING FRIDAY...PER 00Z EURO.
STILL LINGERING UPPER LEVEL TROUGHINESS ON SATURDAY WITH MLCAPES
RISING INTO THE 1000-2000 J/KG RANGE TO SUPPORT LOW CHANCE POPS.
UPPER LEVEL RIDGE BUILDING OUT AHEAD OF STRONG GREAT BASIN 500 MB
LOW ON SATURDAY SHOULD EXERT A BIGGER INFLUENCE FOR THE SECOND HALF
OF THE WEEKEND...ALLOWING FOR TEMPERATURES TO HEAT UP ONCE
AGAIN...WITH 90 DEGREES LIKELY ON SUNDAY...AS SOUTH-SOUTHWEST FLOW
INCREASES OUT AHEAD OF NEXT COLD FRONT...WITH 850 MB TEMPS PROGGED
TO BE IN THE 18-19 C RANGE. UPPER LEVEL RIDGE AXIS ARRIVING SUNDAY
AFTERNOON IS EXPECTED TO PROVIDE ENOUGH MID LEVEL WARMING/SUBSIDENT
BACKDROP TO SQUELCH POTENTIAL CONVECTION. THE SAME CAN NOT BE SAID
FOR EARLY NEXT WEAK AS SOLID HEIGHT FALLS/MOISTURE PLUME/AXIS (PW
VALUES OF 2 INCHES) AND COLD FRONT TRACKS THROUGH THE GREAT LAKES
REGION.
MARINE...
STRENGTHENING HIGH PRESSURE OVER EASTERN CANADA WILL PROMOTE LIGHT
EASTERLY FLOW AS WE HEAD INTO FRIDAY. UPPER LEVEL DISTURBANCE WILL
RESULT IN SCATTERED SHOWERS AND THUNDERSTORMS THROUGH FRIDAY...WITH
A LOW CHANCE ON SATURDAY. WINDS WILL SHIFT TO THE SOUTH OVER THE
WEEKEND...BUT REMAIN LIGHT...AS VERY WARM AIR STREAMS INTO THE
REGION.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....CB
UPDATE.......CB
SHORT TERM...MR
LONG TERM....SF
MARINE.......SF
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
137 PM EDT THU SEP 3 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 412 AM EDT THU SEP 3 2015
THE RAIN OVER THE SOUTHERN AND EASTERN PART OF THE FORECAST AREA
FINALLY SEEMS TO BE MOVING OUT OF THE AREA AS THE UPPER SHORT WAVE
MOVES EAST. THE BIG PROBLEM THIS MORNING IS ACTUALLY DENSE FOG
ACROSS THE WESTERN PART OF THE FORECAST AREA WHERE IT HAS CLEARED
OUT WITH SUFFICIENT LOW LEVEL MOISTURE FROM RAINFALL OVER THE PAST
24 HR. MOST OF THE WESTERN TIER OF COUNTIES HAVE VSBYS LESS THAN ONE
QUARTER OF A MILE AND AS SUCH HAVE OPTED TO GO WITH A DENSE FOG
ADVISORY FOR THIS AREA UNTIL 14Z.
OTHERWISE...AS THE UPPER SHORT WAVE SLOWLY MOVES EAST THIS
MORNING...EXPECT ANY REMAINING SHOWERS TO MOVE OUT OF THE AREA AS
WELL. THE RAP SUGGESTS THAT CYCLONIC FLOW WILL PERSIST THROUGH THE
DAY ACROSS THE EAST. THIS COMBINED WITH LAKE BREEZE CONVERGENCE
ACROSS THE EAST IMPLIES AT LEAST A SLIGHT CHANCE OF SHOWERS THIS
AFTERNOON ACROSS THE FAR EAST. NOT TOO EXCITED ABOUT THUNDERSTORM
CHANCES AS LOCAL RESEARCH SUGGESTS VERY MIMINAL THUNDERSTORM
DEVELOPMENT WITH NORTHERLY MID LEVEL FLOW. ACROSS THE REMAINDER OF
THE AREA...MINIMAL MLCAPE VALUES OF LESS THAN 300 J/KG PER THE
RAP...DRY AIR ASSOCIATED WITH THE HIGH PRES AND BUILDING HEIGHTS
SHOULD PRECLUDE ANY SHOWER/THUNDERSTORM DEVELOPMENT. DESPITE THE
NORTH-NORTHEAST FLOW...IT WILL STILL REMAIN MILD AND RATHER STICKY
WITH HIGHS IN THE UPPER 70S/LOWER 80S...STILL ABOVE NORMAL FOR EARLY
SEPTEMBER.
WITH HIGH PRESSURE IN CONTROL...IT SHOULD BE A QUIET NIGHT TONIGHT.
CANNOT RULE OUT MORE FOG DEVELOPMENT ACROSS THE INTERIOR WITH LIGHT
WINDS AND CLEAR SKIES. TEMPS SHOULD DROP INTO THE UPPER 50S/LOWER
60S.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 452 AM EDT THU SEP 3 2015
PRIME CONCERNS IN LONG TERM INCLUDE EXTENT/STRENGTH OF SHRA/TSRA
THIS WEEKEND INTO LABOR DAY AND MAX TEMPS. FOG WILL ALSO BE ISSUE
AT TIMES WITH HUMID AIRMASS PERSISTING UNTIL COLD FRONT ARRIVES BY
LABOR DAY.
UPPER RIDGE BUILDS BACK OVER UPPER GREAT LAKES ON FRIDAY. REMNANT OF
SHORTWAVE THAT IS MOVING THROUGH ATTM MEANDERS OVER LOWER MICHIGAN
AND MAY DRIFT TOWARD EAST CWA BY EVENING. GFS/NAM SOUNDINGS SEEM TOO
DRY FOR SHRA/TSRA WITH GENERAL EAST SFC WINDS COMING OUT OF HIGH
OVER QUEBEC. SLIGHTLY DRIER TOO WITH UPR 50S TO LOW 60S DWPNTS
INSTEAD OF UPR 60S-NEAR 70. COULD BE FOG AROUND TO START DAY BUT
THAT SHOULD GIVE WAY TO MOSTLY SUNNY SKIES BY LATE MORNING. TEMPS
HELD DOWN BY OVERALL FLOW OFF THE GREAT LAKES AND COOLER TEMPS
ALOFT. EXPECT MID 80S INTERIOR WEST AND UPR 70S NEAR 80 OVER REST OF
CWA.
EDGE OF UPPER RIDGE DRAWS CLOSE ENOUGH FRIDAY NIGHT INTO SATURDAY TO
BRING SHRA/TSRA POSSIBILITY BACK TO THE AREA...ADVECTING IN FM
NORTHERN PLAINS WITH SW MEAN LAYER H85-H3 WINDS. EDGE OF MUCAPE OVER
1000J/KG AS CLOSE AS NORTHERN MN AND NORTHERN WI. ECMWF AND GFS ALSO
BOTH SHOWING SHORTWAVE CURRENTLY OVER FOUR CORNERS TRACKING OVER
NORTHERN MN AND LK SUPERIOR BY 12Z SATURDAY. INCREASING H85 JET
RAMPS UP MOISTURE ADVECTION OVER MN SO HAVE PUT CHANCE POPS OVER
WESTERN LK SUPERIOR ON FRIDAY NIGHT AND SPREAD THEM INTO FAR WEST
CWA ON SATURDAY AS THERE MAY BE GREATER CHANCE OF SHRA/TSRA IN VCNTY
OF THE SHORTWAVE AND GIVEN THE HIGHER MUCAPES. MLCAPES ALSO PUSH UP
TOWARD 1000J/KG DURING AFTN SO THERE MAY BE ADDITIONAL SHRA/TSRA TRY
TO FORM DUE TO DAYTIME HEATING AND POSSIBLY AFFECTS FM THE
SHORTWAVE. PROBABLY WILL BE SOME FOG AROUND TO START DAY AGAIN. SE
WINDS ADDING MOISTURE OFF LK MICHIGAN AND RADIATIONAL COOLING FRIDAY
NIGHT SHOULD LEAD TO BEST BET FOR FOG OVER INTERIOR CNTRL AND NEAR
LK MICHIGAN. ONCE FOG EVADES...PARTLY SUNNY SKIES WILL ALLOW TEMPS
TO WARM QUITE A BIT OVER FRIDAY. H85 TEMPS PUSHING 19-20C BY AFTN
AND MORE OF A SOUTH WIND COMPARED TO FRIDAY POINT TO MID-UPR 80S FOR
MOST WITH A FEW 90 DEGREE READINGS POSSIBLE INTERIOR WEST AND NEAR
LK SUPERIOR WITH DOWNSLOPING WINDS.
STRONGER SHORTWAVE LIFTS OVER UPPER MISSISSIPPI RIVER VALLEY SAT
NIGHT IN SW FLOW ALOFT. AT SFC...LOW PRESSURE SYSTEM WILL BE
DEVELOPING OVER HIGH PLAINS WHILE TROUGHING EXTENDS ACROSS NORTHERN
PLAINS AND TO NORTHWEST ONTARIO. SOUTH WINDS AHEAD OF TROUGH SHOULD
LEAD TO WARM/MUGGY NIGHT OVER UPR MICHIGAN. MUCAPES REMAIN HIGH AT
1000-2000J/KG FM NORTHERN PLAINS ACROSS UPPER GREAT LAKES. IF
SHORTWAVE TRACKS CLOSE ENOUGH...COULD SEE SHRA/TSRA PUSH OVER WEST
HALF OF CWA AT LEAST WITH H85-H3 WINDS FM THE WSW. UNLIKE FRIDAY
NIGHT WITH SIMILAR SETUP...SHEAR IS FORECAST TO BE MUCH STRONGER AS
1-6KM SHEAR VALUES ARE 30-40 KTS. LOW-LEVEL JET AT H85 OVER 40 KTS
IS AIMED TOWARD UPPER MISSISSIPPI RIVER VALLEY AND AT LEAST WESTERN
FRINGE OF UPPER GREAT LAKES. NOT SURE IF GREATER MLCAPES WELL TO SW
OF HERE WILL KEEP MAIN SHRA/TSRA THERE SINCE THE SHORTWAVE IS MUCH
FARTHER NORTH. CARRIED CHANCE POPS OVER WEST CWA...SLIGHT CHANCES
FARTHER EAST. GIVEN THE SHEAR AND INSTABILITY...THERE IS AT LEAST A
REMOTE CHANCE OF STRONG TO SEVERE STORMS AS SHOWN BY LATEST DAY3
OUTLOOK FM SPC.
STRONG SHORTWAVE SLIDES FM ROCKIES TO THE NORTHERN PLAINS SUNDAY
INTO SUNDAY NIGHT. ASSOCIATED SFC LOW BOTTOMS OUT AT 990-1000MB OVER
SOUTHERN MANITOBA BY MONDAY MORNING. MOISTURE ADVECTION AND
CONTINUAL FEED OF STRONG INSTABILITY SHOULD SUPPORT MULTIPLE CLUSTERS
OF SHRA/TSRA WITHIN H85 JET AXIS AND JUST AHEAD OF SFC FRONT. NEVER
SURE HOW FAR SHRA/TSRA WILL BREAK OUT AHEAD OF MAIN FRONT AS WITHOUT
STRONG FORCING FM A YET TO BE DETERMINED SHORTWAVE THERE CAN ALWAYS
BE CAPPING CONCERNS. WILL CONTINUE TO HIGHLIGHT WEST CWA FOR BETTER
CHANCES AT THIS POINT WITH WSW MEAN LAYER WINDS. ANOTHER WARM AND
HUMID DAY AHEAD OF THE FRONT. H85 RIDGE AHEAD OF THE FRONT POINTS TO
READINGS SIMILAR TO SAT AS LONG AS CLOUDS/SHRA/TSRA DONT DISRUPT
THINGS TOO MUCH. PUT THE WARMEST TEMPS ON SUNDAY OVER CNTRL CWA
CLOSER TO LK SUPERIOR WITH DOWNSLOPING SOUTH WINDS. BEST CHANCE FOR
READINGS TO HIT 90 DEGREES WOULD BE BARAGA/BIG
BAY/MARQUETTE/HARVEY/MUNISING.
ALL THIS SHRA/TSRA ACTIVITY SHOULD EASE EAST ACROSS REST OF CWA AS
THE MAIN SFC-H85 FRONTS AND ASSOCIATED THETA-E RIDGE AND RIBBON OF
PWATS OVER 1.75 INCHES CROSS SUNDAY NIGHT INTO MONDAY. MLCAPES OVER
1000J/KG INITIALLY BUT THESE TAIL OFF WITH NIGHTTIME COOLING.
MUCAPES WELL OVER 1000J/KG MAY ALLOW STORMS TO TRY TO BECOME
ELEVATED AFTER BECOMING SFC BASED...BUT THAT IS ALWAYS A TRICKY
TRANSITION. STRONG H85 JET AND MOISTURE TRANSPORT INTO THE AREA
OF HIGHER MUCAPES WILL AID THIS TRANSITION THOUGH. CONSENSUS HIGH
CHANCE TO LOW-END LIKELY POPS SEEMED FINE FOR SUNDAY NIGHT. BETTER
POPS ON LABOR DAY END UP BEING OVER EAST HALF WITH GREATER MOISTURE
ADVECTION AHEAD OF THE EXITING SFC-H85 FRONT. H85 TEMPS DO NOT CRASH
DOWN AS IT LOOKED LIKE A FEW DAYS AGO...SO UPR 70S TO LOW OR
POSSIBLY MID 80S WILL WORK FOR TEMPS ON MONDAY. WARMEST READINGS
CNTRL CWA IRON MTN TO MARQUETTE AND MUNISING. THROUGH THE COOLING IS
NOT AS SIGNIFICANT...THE DRYING IS WITH DWPNTS FALLING OFF INTO THE
50S ON MONDAY AFTN OVER THE WEST AND DOWN TO AROUND 50 BY LATE
MONDAY NIGHT. COULD EVEN SEE 40S DWPNTS ON TUESDAY AS COOLING
BECOMES MORE PRONOUNCED. EXPECT HIGHS UPR 60S TO LOW 70S ON TUE AND
THEN MAINLY IN THE 60S FOR WED. GUSTY WINDS AS THE COOLING OCCURS
ESPECIALLY NEAR LK SUPERIOR. NEXT CHANCE OF RAIN PRETTY WELL AGREED
UPON BY GFS AND ECMWF FOR TUE NIGHT INTO WED MORNING.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 137 PM EDT THU SEP 3 2015
EXPECT VFR CONDITIONS THROUGH THIS EVENING. CLEAR SKIES AND LIGHT
WINDS WILL LIKELY CAUSE IFR CONDITIONS ONCE AGAIN LATER TONIGHT INTO
FRIDAY MORNING...MAINLY AT KIWD/KSAW WHILE MVFR VSBY IS EXPECTED AT
KCMX.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 412 AM EDT THU SEP 3 2015
DENSE FOG HAS DEVELOPED ACROSS THE WESTERN HALF OF THE
LAKE...ESPECIALLY OVER AREAS THAT SAW RAIN YESTERDAY. AS SUCH...HAVE
ISSUED A DENSE FOG ADVY FOR THE ENTIRE WEST HALF OF THE LAKE THROUGH
EARLY THIS AFTERNOON. 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...
DENSE FOG ADVISORY UNTIL 2 PM EDT /1 PM CDT/ THIS AFTERNOON FOR
LSZ162-240>243-246-247-263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...MRD
LONG TERM...JLA
AVIATION...JLB
MARINE...MRD
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1239 PM EDT THU SEP 3 2015
.UPDATE...
DUAL SHORTWAVES OVER THE WESTERN AND CENTRAL GREAT LAKES WILL
REMAIN THE SOLE FORCING MECHANISMS THROUGH THE NEXT 18 HOURS. THE
SMALL MCS IMPACTING LOWER MICHIGAN IS TIED TO THE FIRST LOWER
COLUMN PV ANOMALY...THE SECOND IS THE SHORTWAVE CIRCULATION THAT
IS NOW DROPPING INTO THE BACKSIDE OF THE GEOPOTENTIAL HEIGHT
WEAKNESS OVER FAR NORTHERN WISCONSIN. AT THE BIG PICTURE...LOWER
DELTA X SOLUTIONS/GLOBAL MODELS SUGGEST A PHASING OF THE TWO
SHORTWAVES AND A SUBSEQUENT STALLING OF THE COMBINED PV ANOMALY
LATE THIS AFTERNOON AND TONIGHT.
THE MCS THAT HAS BEEN PUSHING ACROSS THE NORTHERN CWA CONTINUES TO
MAKE SOME PROGRESS EASTWARD. A LINEAR EXTRAPOLATION OF REGIONAL Z
MOSAIC CONTINUES TO SUPPORT SOME SLIGHT SOUTHWARD DRIFT WITH TIME
ON THE TRACK OF THE MCS. THIS SOUTHWARD DRIFT SHOULD AT LEAST BE
PARTIALLY SUPPORTIVE BY ADDITIONAL OUTFLOW DEVELOPMENT ALONG THE
SOUTHERN FLANK. THERE HAS BEEN SOME MODEST...CONTINUED DEVELOPMENT
DURING THE PAST FEW HOURS. NWP GUIDANCE WITH A BULLISH HRRR AND
BOTH NAM/ECMWF SUPPORT BRING ADDITIONAL CONVECTIVE DEVELOPMENT FOR
ALL OF SOUTHEASTERN MICHIGAN DURING THE AFTERNOON HOURS. GIVEN THE
LACK OF AN AGGRESSIVE SOUTHERN PROGRESSION TO THE
STRATUS/CIRRUS/CU DECK EXPECTATIONS ARE FOR THE
INSTABILITY/BUOYANCY GRADIENT TO REMAIN DRAPED THROUGH FAR
SOUTHERN SECTIONS OF THE CWA. THE FORECAST IS SKEWED ON THE
AGGRESSIVE SIDE WITH RESPECT TO RAIN AND THUNDERSTORM ACTIVITY
THIS LATER THIS AFTERNOON AND EVENING. THERE DOES REMAIN A SLIVER
OF DOUBT THAT THUNDERSTORMS WILL FILL IN COMPLETELY ACROSS FAR
SOUTHERN LOWER MICHIGAN AND IMPACT DETROIT METRO DIRECTLY. STORM
BEHAVIOR TODAY IS EXPECTED TO REMAIN MORE OF A PULSE TYPE NATURE
WITH PERHAPS SOME EMBEDDED LINE TYPE FEATURES. THEREFORE...A LOW
END DAMAGING WIND GUST THREAT EXISTS THIS AFTERNOON AND WILL
PERHAPS BE A CIRCUMSTANCE OF CONSTRUCTIVE CELL MERGERS OR
PRECIPITATION LOADING EFFECTS.
A CONCERNING POTENTIAL WILL CONTINUE TO BE A HEAVY RAINFALL
THREAT...ESPECIALLY UNDER THE DIRECTION OF ADVERTISED PHASING AND
STALLING OUT OF PV MAX OVERHEAD. PWATS ARE AT APPROXIMATELY 1.8
INCHES. SOME SAMPLED RAINFALL RATES EARLIER OFF OF RADAR BASED
PRECIPITATION PRODUCT SUGGESTS 1.25 INCHES OF RAINFALL IS
POSSIBLE IN ROUGHLY 40 MINUTES. WILL BE MONITORING ACTIVITY THIS
AFTERNOON FOR ANY TRAINING OR STATIONARY BEHAVIOR OF THUNDERSTORMS.
&&
.AVIATION...ISSUED 732 AM EDT THU SEP 3 2015
EXTREMELY MOIST AND UNSTABLE ENVIRONMENT TODAY WILL PROVIDE A
FAVORABLE ENVIRONMENT FOR SHOWER AND THUNDERSTORM DEVELOPMENT
AREAWIDE. WHILE THERE REMAINS SOME UNCERTAINTY AS TO POTENTIAL
COVERAGE...CONFIDENCE IS HIGH ENOUGH TO INCLUDE A SPECIFIC MENTION
TO HIGHLIGHT THE MOST LIKELY PERIOD FOR THUNDERSTORMS. OUTSIDE OF
THUNDERSTORMS...EXPANDING COVERAGE OF DIURNAL VFR CU CENTERED ON THE
AFTERNOON/EVENING PERIOD. THE MOIST LOW LEVEL CONDITIONS AND
PROSPECTS FOR WET GROUND WITH RECENT RAINFALL WILL BRING A GREATER
POTENTIAL FOR FOG DEVELOPMENT TONIGHT. POSSIBILITY EXISTS FOR ONE
OR MORE TERMINALS TO DROP INTO LIFR DURING THE EARLY MORNING
PERIOD...CONFIDENCE TOO LOW YET TO INCLUDE BUT WILL HIGHLIGHT WITH
IFR VSBY RESTRICTIONS.
FOR DTW...GREATEST POTENTIAL FOR THUNDERSTORMS CENTERED WITHIN THE
18Z-00Z WINDOW...ALTHOUGH A LOWER PROBABILITY WILL EXIST RIGHT
THROUGH THURSDAY NIGHT.
//DTW THRESHOLD PROBABILITIES...
* LOW FOR CIG AOB 5KFT THIS AFTERNOON AND EVENING
* MEDIUM FOR THUNDERSTORMS THIS AFTERNOON AND EVENING
&&
.PREV DISCUSSION...ISSUED 333 AM EDT THU SEP 3 2015
SHORT TERM...TODAY AND TONIGHT
ATTENTION OVER THE NEXT 24 TO 36 HOURS CENTERS ON THE INBOUND SLOWLY
MOVING MID LEVEL WAVE CURRENTLY CENTERED ACROSS THE LAKE MICHIGAN
CORRIDOR. LITTLE VARIATION IN THE UNDERLYING LOW LEVEL
THERMODYNAMIC PROFILE HEADING INTO TODAY...WITH SE MICHIGAN FIRMLY
ENTRENCHED WITHIN A MOISTURE RICH LOW LEVEL ENVIRONMENT /LOWER 70S
DEWPOINTS/. AS NOTED YESTERDAY...THIS WILL AGAIN TRANSLATE INTO
SUBSTANTIAL LOW LEVEL INSTABILITY (2500+ J/KG SBCAPE) WITHIN A VERY
STEEP LAPSE RATE ENVIRONMENT. INCREASING DPVA AND AN ACCOMPANYING POCKET
OF COOLER MID LEVEL TEMPERATURES WILL CONTRIBUTE AN ADDITIONAL
COMPONENT OF DESTABILIZATION AND MORE FOCUSED ASCENT FOR TODAY.
THIS ENVIRONMENT SEEMS CONDUCIVE FOR A MORE SIZABLE EXPANSION IN
CONVECTIVE COVERAGE LOCALLY...AND WORTHY OF A NUDGE UPWARD IN
POPS...PARTICULARLY FOR THE AFTERNOON/EVENING PERIODS. THE HIGH
MOISTURE CONTENT AND CORRESPONDING POTENTIAL FOR SIGNIFICANT
PRECIPITATION LOADING WITHIN THE DEEPEST CONVECTIVE CELLS WILL
AGAIN PRESENT THE POTENTIAL FOR STRONGER WIND GUSTS...WITH AT
LEAST AN OUTSIDE POSSIBILITY THAT AN ISOLATED STORM OR TWO CAN
GENERATE A PEAK GUST NEARING SEVERE LIMITS. SOLID HEAVY RAINFALL
THREAT GIVEN LIKELY LIMITED STORM MOTION WITHIN THIS HIGH CAPE
ENVIRONMENT. HIGHS TODAY A TOUCH LOWER WITH THE ENSUING EXPANSION
IN CONVECTION/CLOUD COVER LIKELY UNDERCUTTING THE HEATING
POTENTIAL SLIGHTLY. READINGS TOPPING OUT IN THE LOWER AND MIDDLE
80S...HEAT INDICES APPROACHING 90.
GRADUAL COOLING VIA DIABATIC PROCESSES AND ANY OUTFLOW WILL FAVOR A
DIMINISHING TREND TO EXISTING CONVECTIVE ACTIVITY BY EARLY TONIGHT.
HOWEVER THE UNDERLYING ENVIRONMENT WILL STILL REMAIN FAVORABLE FOR
ADDITIONAL ISOLATED-SCATTERED DEVELOPMENT THROUGHOUT THE NIGHT.
INCREASING POTENTIAL FOR FOG OVERNIGHT...MOIST NEAR SURFACE
ENVIRONMENT AUGMENTED BY THE RAINFALL AND WEAK GRADIENT. A CORRIDOR
OF DENSE FOG FOR THE EARLY MORNING COMMUTE NOT OUT OF THE QUESTION.
LONG TERM...
MULTIPLE UPPER WAVES UPSTREAM OVER UPPER MISSISSIPPI RIVER VALLEY
THIS MORNING...WHICH WILL CONSOLIDATE OVER THE WESTERN/CENTRAL GREAT
LAKES TONIGHT INTO FRIDAY...BUT THE EXACT POSITION OF THE DEVELOPED
MID LEVEL CIRCULATION/500 MB LOW IS QUESTION...AS 00Z NAM/GFS ARE
INDICATING A FARTHER SOUTH/WEST SOLUTION...NEAR CHICAGO...WHILE
EURO/CANADIAN REMAIN STEADFAST WITH 500 MB LOW FARTHER NORTH/EAST
OVER NORTHERN LOWER MICHIGAN. EITHER WAY...CHANCE POPS STILL SEEM
WARRANTED...EVEN WITH THE STRENGTHENING HIGH PRESSURE OVER EASTERN
CANADA (1025 MB)...AS THE LOW LEVEL SOUTHEAST/EAST FLOW WILL
INCREASE A BIT...BUT THERE ACTUALLY LOOKS TO BE MODEST MOISTURE
ADVECTION FROM WESTERN PA/LAKE ERIE. MLCAPES PROGGED TO INCREASE
INTO THE 500 TO 1500 J/KG RANGE DURING FRIDAY...PER 00Z EURO.
STILL LINGERING UPPER LEVEL TROUGHINESS ON SATURDAY WITH MLCAPES
RISING INTO THE 1000-2000 J/KG RANGE TO SUPPORT LOW CHANCE POPS.
UPPER LEVEL RIDGE BUILDING OUT AHEAD OF STRONG GREAT BASIN 500 MB
LOW ON SATURDAY SHOULD EXERT A BIGGER INFLUENCE FOR THE SECOND HALF
OF THE WEEKEND...ALLOWING FOR TEMPERATURES TO HEAT UP ONCE
AGAIN...WITH 90 DEGREES LIKELY ON SUNDAY...AS SOUTH-SOUTHWEST FLOW
INCREASES OUT AHEAD OF NEXT COLD FRONT...WITH 850 MB TEMPS PROGGED
TO BE IN THE 18-19 C RANGE. UPPER LEVEL RIDGE AXIS ARRIVING SUNDAY
AFTERNOON IS EXPECTED TO PROVIDE ENOUGH MID LEVEL WARMING/SUBSIDENT
BACKDROP TO SQUELCH POTENTIAL CONVECTION. THE SAME CAN NOT BE SAID
FOR EARLY NEXT WEAK AS SOLID HEIGHT FALLS/MOISTURE PLUME/AXIS (PW
VALUES OF 2 INCHES) AND COLD FRONT TRACKS THROUGH THE GREAT LAKES
REGION.
MARINE...
STRENGTHENING HIGH PRESSURE OVER EASTERN CANADA WILL PROMOTE LIGHT
EASTERLY FLOW AS WE HEAD INTO FRIDAY. UPPER LEVEL DISTURBANCE WILL
RESULT IN SCATTERED SHOWERS AND THUNDERSTORMS THROUGH FRIDAY...WITH
A LOW CHANCE ON SATURDAY. WINDS WILL SHIFT TO THE SOUTH OVER THE
WEEKEND...BUT REMAIN LIGHT...AS VERY WARM AIR STREAMS INTO THE
REGION.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
UPDATE.......CB
AVIATION.....MR
SHORT TERM...MR
LONG TERM....SF
MARINE.......SF
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
740 AM EDT THU SEP 3 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 412 AM EDT THU SEP 3 2015
THE RAIN OVER THE SOUTHERN AND EASTERN PART OF THE FORECAST AREA
FINALLY SEEMS TO BE MOVING OUT OF THE AREA AS THE UPPER SHORT WAVE
MOVES EAST. THE BIG PROBLEM THIS MORNING IS ACTUALLY DENSE FOG
ACROSS THE WESTERN PART OF THE FORECAST AREA WHERE IT HAS CLEARED
OUT WITH SUFFICIENT LOW LEVEL MOISTURE FROM RAINFALL OVER THE PAST
24 HR. MOST OF THE WESTERN TIER OF COUNTIES HAVE VSBYS LESS THAN ONE
QUARTER OF A MILE AND AS SUCH HAVE OPTED TO GO WITH A DENSE FOG
ADVISORY FOR THIS AREA UNTIL 14Z.
OTHERWISE...AS THE UPPER SHORT WAVE SLOWLY MOVES EAST THIS
MORNING...EXPECT ANY REMAINING SHOWERS TO MOVE OUT OF THE AREA AS
WELL. THE RAP SUGGESTS THAT CYCLONIC FLOW WILL PERSIST THROUGH THE
DAY ACROSS THE EAST. THIS COMBINED WITH LAKE BREEZE CONVERGENCE
ACROSS THE EAST IMPLIES AT LEAST A SLIGHT CHANCE OF SHOWERS THIS
AFTERNOON ACROSS THE FAR EAST. NOT TOO EXCITED ABOUT THUNDERSTORM
CHANCES AS LOCAL RESEARCH SUGGESTS VERY MIMINAL THUNDERSTORM
DEVELOPMENT WITH NORTHERLY MID LEVEL FLOW. ACROSS THE REMAINDER OF
THE AREA...MINIMAL MLCAPE VALUES OF LESS THAN 300 J/KG PER THE
RAP...DRY AIR ASSOCIATED WITH THE HIGH PRES AND BUILDING HEIGHTS
SHOULD PRECLUDE ANY SHOWER/THUNDERSTORM DEVELOPMENT. DESPITE THE
NORTH-NORTHEAST FLOW...IT WILL STILL REMAIN MILD AND RATHER STICKY
WITH HIGHS IN THE UPPER 70S/LOWER 80S...STILL ABOVE NORMAL FOR EARLY
SEPTEMBER.
WITH HIGH PRESSURE IN CONTROL...IT SHOULD BE A QUIET NIGHT TONIGHT.
CANNOT RULE OUT MORE FOG DEVELOPMENT ACROSS THE INTERIOR WITH LIGHT
WINDS AND CLEAR SKIES. TEMPS SHOULD DROP INTO THE UPPER 50S/LOWER
60S.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 452 AM EDT THU SEP 3 2015
PRIME CONCERNS IN LONG TERM INCLUDE EXTENT/STRENGTH OF SHRA/TSRA
THIS WEEKEND INTO LABOR DAY AND MAX TEMPS. FOG WILL ALSO BE ISSUE
AT TIMES WITH HUMID AIRMASS PERSISTING UNTIL COLD FRONT ARRIVES BY
LABOR DAY.
UPPER RIDGE BUILDS BACK OVER UPPER GREAT LAKES ON FRIDAY. REMNANT OF
SHORTWAVE THAT IS MOVING THROUGH ATTM MEANDERS OVER LOWER MICHIGAN
AND MAY DRIFT TOWARD EAST CWA BY EVENING. GFS/NAM SOUNDINGS SEEM TOO
DRY FOR SHRA/TSRA WITH GENERAL EAST SFC WINDS COMING OUT OF HIGH
OVER QUEBEC. SLIGHTLY DRIER TOO WITH UPR 50S TO LOW 60S DWPNTS
INSTEAD OF UPR 60S-NEAR 70. COULD BE FOG AROUND TO START DAY BUT
THAT SHOULD GIVE WAY TO MOSTLY SUNNY SKIES BY LATE MORNING. TEMPS
HELD DOWN BY OVERALL FLOW OFF THE GREAT LAKES AND COOLER TEMPS
ALOFT. EXPECT MID 80S INTERIOR WEST AND UPR 70S NEAR 80 OVER REST OF
CWA.
EDGE OF UPPER RIDGE DRAWS CLOSE ENOUGH FRIDAY NIGHT INTO SATURDAY TO
BRING SHRA/TSRA POSSIBILITY BACK TO THE AREA...ADVECTING IN FM
NORTHERN PLAINS WITH SW MEAN LAYER H85-H3 WINDS. EDGE OF MUCAPE OVER
1000J/KG AS CLOSE AS NORTHERN MN AND NORTHERN WI. ECMWF AND GFS ALSO
BOTH SHOWING SHORTWAVE CURRENTLY OVER FOUR CORNERS TRACKING OVER
NORTHERN MN AND LK SUPERIOR BY 12Z SATURDAY. INCREASING H85 JET
RAMPS UP MOISTURE ADVECTION OVER MN SO HAVE PUT CHANCE POPS OVER
WESTERN LK SUPERIOR ON FRIDAY NIGHT AND SPREAD THEM INTO FAR WEST
CWA ON SATURDAY AS THERE MAY BE GREATER CHANCE OF SHRA/TSRA IN VCNTY
OF THE SHORTWAVE AND GIVEN THE HIGHER MUCAPES. MLCAPES ALSO PUSH UP
TOWARD 1000J/KG DURING AFTN SO THERE MAY BE ADDITIONAL SHRA/TSRA TRY
TO FORM DUE TO DAYTIME HEATING AND POSSIBLY AFFECTS FM THE
SHORTWAVE. PROBABLY WILL BE SOME FOG AROUND TO START DAY AGAIN. SE
WINDS ADDING MOISTURE OFF LK MICHIGAN AND RADIATIONAL COOLING FRIDAY
NIGHT SHOULD LEAD TO BEST BET FOR FOG OVER INTERIOR CNTRL AND NEAR
LK MICHIGAN. ONCE FOG EVADES...PARTLY SUNNY SKIES WILL ALLOW TEMPS
TO WARM QUITE A BIT OVER FRIDAY. H85 TEMPS PUSHING 19-20C BY AFTN
AND MORE OF A SOUTH WIND COMPARED TO FRIDAY POINT TO MID-UPR 80S FOR
MOST WITH A FEW 90 DEGREE READINGS POSSIBLE INTERIOR WEST AND NEAR
LK SUPERIOR WITH DOWNSLOPING WINDS.
STRONGER SHORTWAVE LIFTS OVER UPPER MISSISSIPPI RIVER VALLEY SAT
NIGHT IN SW FLOW ALOFT. AT SFC...LOW PRESSURE SYSTEM WILL BE
DEVELOPING OVER HIGH PLAINS WHILE TROUGHING EXTENDS ACROSS NORTHERN
PLAINS AND TO NORTHWEST ONTARIO. SOUTH WINDS AHEAD OF TROUGH SHOULD
LEAD TO WARM/MUGGY NIGHT OVER UPR MICHIGAN. MUCAPES REMAIN HIGH AT
1000-2000J/KG FM NORTHERN PLAINS ACROSS UPPER GREAT LAKES. IF
SHORTWAVE TRACKS CLOSE ENOUGH...COULD SEE SHRA/TSRA PUSH OVER WEST
HALF OF CWA AT LEAST WITH H85-H3 WINDS FM THE WSW. UNLIKE FRIDAY
NIGHT WITH SIMILAR SETUP...SHEAR IS FORECAST TO BE MUCH STRONGER AS
1-6KM SHEAR VALUES ARE 30-40 KTS. LOW-LEVEL JET AT H85 OVER 40 KTS
IS AIMED TOWARD UPPER MISSISSIPPI RIVER VALLEY AND AT LEAST WESTERN
FRINGE OF UPPER GREAT LAKES. NOT SURE IF GREATER MLCAPES WELL TO SW
OF HERE WILL KEEP MAIN SHRA/TSRA THERE SINCE THE SHORTWAVE IS MUCH
FARTHER NORTH. CARRIED CHANCE POPS OVER WEST CWA...SLIGHT CHANCES
FARTHER EAST. GIVEN THE SHEAR AND INSTABILITY...THERE IS AT LEAST A
REMOTE CHANCE OF STRONG TO SEVERE STORMS AS SHOWN BY LATEST DAY3
OUTLOOK FM SPC.
STRONG SHORTWAVE SLIDES FM ROCKIES TO THE NORTHERN PLAINS SUNDAY
INTO SUNDAY NIGHT. ASSOCIATED SFC LOW BOTTOMS OUT AT 990-1000MB OVER
SOUTHERN MANITOBA BY MONDAY MORNING. MOISTURE ADVECTION AND
CONTINUAL FEED OF STRONG INSTABILITY SHOULD SUPPORT MULTIPLE CLUSTERS
OF SHRA/TSRA WITHIN H85 JET AXIS AND JUST AHEAD OF SFC FRONT. NEVER
SURE HOW FAR SHRA/TSRA WILL BREAK OUT AHEAD OF MAIN FRONT AS WITHOUT
STRONG FORCING FM A YET TO BE DETERMINED SHORTWAVE THERE CAN ALWAYS
BE CAPPING CONCERNS. WILL CONTINUE TO HIGHLIGHT WEST CWA FOR BETTER
CHANCES AT THIS POINT WITH WSW MEAN LAYER WINDS. ANOTHER WARM AND
HUMID DAY AHEAD OF THE FRONT. H85 RIDGE AHEAD OF THE FRONT POINTS TO
READINGS SIMILAR TO SAT AS LONG AS CLOUDS/SHRA/TSRA DONT DISRUPT
THINGS TOO MUCH. PUT THE WARMEST TEMPS ON SUNDAY OVER CNTRL CWA
CLOSER TO LK SUPERIOR WITH DOWNSLOPING SOUTH WINDS. BEST CHANCE FOR
READINGS TO HIT 90 DEGREES WOULD BE BARAGA/BIG
BAY/MARQUETTE/HARVEY/MUNISING.
ALL THIS SHRA/TSRA ACTIVITY SHOULD EASE EAST ACROSS REST OF CWA AS
THE MAIN SFC-H85 FRONTS AND ASSOCIATED THETA-E RIDGE AND RIBBON OF
PWATS OVER 1.75 INCHES CROSS SUNDAY NIGHT INTO MONDAY. MLCAPES OVER
1000J/KG INITIALLY BUT THESE TAIL OFF WITH NIGHTTIME COOLING.
MUCAPES WELL OVER 1000J/KG MAY ALLOW STORMS TO TRY TO BECOME
ELEVATED AFTER BECOMING SFC BASED...BUT THAT IS ALWAYS A TRICKY
TRANSITION. STRONG H85 JET AND MOISTURE TRANSPORT INTO THE AREA
OF HIGHER MUCAPES WILL AID THIS TRANSITION THOUGH. CONSENSUS HIGH
CHANCE TO LOW-END LIKELY POPS SEEMED FINE FOR SUNDAY NIGHT. BETTER
POPS ON LABOR DAY END UP BEING OVER EAST HALF WITH GREATER MOISTURE
ADVECTION AHEAD OF THE EXITING SFC-H85 FRONT. H85 TEMPS DO NOT CRASH
DOWN AS IT LOOKED LIKE A FEW DAYS AGO...SO UPR 70S TO LOW OR
POSSIBLY MID 80S WILL WORK FOR TEMPS ON MONDAY. WARMEST READINGS
CNTRL CWA IRON MTN TO MARQUETTE AND MUNISING. THROUGH THE COOLING IS
NOT AS SIGNIFICANT...THE DRYING IS WITH DWPNTS FALLING OFF INTO THE
50S ON MONDAY AFTN OVER THE WEST AND DOWN TO AROUND 50 BY LATE
MONDAY NIGHT. COULD EVEN SEE 40S DWPNTS ON TUESDAY AS COOLING
BECOMES MORE PRONOUNCED. EXPECT HIGHS UPR 60S TO LOW 70S ON TUE AND
THEN MAINLY IN THE 60S FOR WED. GUSTY WINDS AS THE COOLING OCCURS
ESPECIALLY NEAR LK SUPERIOR. NEXT CHANCE OF RAIN PRETTY WELL AGREED
UPON BY GFS AND ECMWF FOR TUE NIGHT INTO WED MORNING.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 740 AM EDT THU SEP 3 2015
LIFR/VLIFR CONDITIONS WILL PERSIST AT IWD AND CMX FOR THE NEXT HOUR
OR TWO BEFORE CLEARING. CONDITIONS AT SAW HAVE JUST LOWERED TO
IFR...BUT THE EXPECTATION IS THAT THEY WILL ALSO SEE MVFR THEN VFR
SOON AFTER SUNRISE. OTHERWISE...AFTER THE MORNING FOG AND LOW
STRATUS...EXPECT VFR CONDITIONS THROUGH THIS EVENING. CLEAR SKIES
AND LIGHT WINDS WILL LIKELY CAUSE IFR CONDITIONS ONCE AGAIN LATER
TONIGHT INTO FRIDAY MORNING AT ALL SITES.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 412 AM EDT THU SEP 3 2015
DENSE FOG HAS DEVELOPED ACROSS THE WESTERN HALF OF THE
LAKE...ESPECIALLY OVER AREAS THAT SAW RAIN YESTERDAY. AS SUCH...HAVE
ISSUED A DENSE FOG ADVY FOR THE ENTIRE WEST HALF OF THE LAKE THROUGH
EARLY THIS AFTERNOON. 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...
DENSE FOG ADVISORY UNTIL 10 AM EDT /9 AM CDT/ THIS MORNING FOR
MIZ001>003-009-084.
LAKE SUPERIOR...
DENSE FOG ADVISORY UNTIL 2 PM EDT /1 PM CDT/ THIS AFTERNOON FOR
LSZ162-240>248-263>265.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...MRD
LONG TERM...JLA
AVIATION...MRD
MARINE...MRD
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
454 AM EDT THU SEP 3 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 412 AM EDT THU SEP 3 2015
THE RAIN OVER THE SOUTHERN AND EASTERN PART OF THE FORECAST AREA
FINALLY SEEMS TO BE MOVING OUT OF THE AREA AS THE UPPER SHORT WAVE
MOVES EAST. THE BIG PROBLEM THIS MORNING IS ACTUALLY DENSE FOG
ACROSS THE WESTERN PART OF THE FORECAST AREA WHERE IT HAS CLEARED
OUT WITH SUFFICIENT LOW LEVEL MOISTURE FROM RAINFALL OVER THE PAST
24 HR. MOST OF THE WESTERN TIER OF COUNTIES HAVE VSBYS LESS THAN ONE
QUARTER OF A MILE AND AS SUCH HAVE OPTED TO GO WITH A DENSE FOG
ADVISORY FOR THIS AREA UNTIL 14Z.
OTHERWISE...AS THE UPPER SHORT WAVE SLOWLY MOVES EAST THIS
MORNING...EXPECT ANY REMAINING SHOWERS TO MOVE OUT OF THE AREA AS
WELL. THE RAP SUGGESTS THAT CYCLONIC FLOW WILL PERSIST THROUGH THE
DAY ACROSS THE EAST. THIS COMBINED WITH LAKE BREEZE CONVERGENCE
ACROSS THE EAST IMPLIES AT LEAST A SLIGHT CHANCE OF SHOWERS THIS
AFTERNOON ACROSS THE FAR EAST. NOT TOO EXCITED ABOUT THUNDERSTORM
CHANCES AS LOCAL RESEARCH SUGGESTS VERY MIMINAL THUNDERSTORM
DEVELOPMENT WITH NORTHERLY MID LEVEL FLOW. ACROSS THE REMAINDER OF
THE AREA...MINIMAL MLCAPE VALUES OF LESS THAN 300 J/KG PER THE
RAP...DRY AIR ASSOCIATED WITH THE HIGH PRES AND BUILDING HEIGHTS
SHOULD PRECLUDE ANY SHOWER/THUNDERSTORM DEVELOPMENT. DESPITE THE
NORTH-NORTHEAST FLOW...IT WILL STILL REMAIN MILD AND RATHER STICKY
WITH HIGHS IN THE UPPER 70S/LOWER 80S...STILL ABOVE NORMAL FOR EARLY
SEPTEMBER.
WITH HIGH PRESSURE IN CONTROL...IT SHOULD BE A QUIET NIGHT TONIGHT.
CANNOT RULE OUT MORE FOG DEVELOPMENT ACROSS THE INTERIOR WITH LIGHT
WINDS AND CLEAR SKIES. TEMPS SHOULD DROP INTO THE UPPER 50S/LOWER
60S.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 452 AM EDT THU SEP 3 2015
PRIME CONCERNS IN LONG TERM INCLUDE EXTENT/STRENGTH OF SHRA/TSRA
THIS WEEKEND INTO LABOR DAY AND MAX TEMPS. FOG WILL ALSO BE ISSUE
AT TIMES WITH HUMID AIRMASS PERSISTING UNTIL COLD FRONT ARRIVES BY
LABOR DAY.
UPPER RIDGE BUILDS BACK OVER UPPER GREAT LAKES ON FRIDAY. REMNANT OF
SHORTWAVE THAT IS MOVING THROUGH ATTM MEANDERS OVER LOWER MICHIGAN
AND MAY DRIFT TOWARD EAST CWA BY EVENING. GFS/NAM SOUNDINGS SEEM TOO
DRY FOR SHRA/TSRA WITH GENERAL EAST SFC WINDS COMING OUT OF HIGH
OVER QUEBEC. SLIGHTLY DRIER TOO WITH UPR 50S TO LOW 60S DWPNTS
INSTEAD OF UPR 60S-NEAR 70. COULD BE FOG AROUND TO START DAY BUT
THAT SHOULD GIVE WAY TO MOSTLY SUNNY SKIES BY LATE MORNING. TEMPS
HELD DOWN BY OVERALL FLOW OFF THE GREAT LAKES AND COOLER TEMPS
ALOFT. EXPECT MID 80S INTERIOR WEST AND UPR 70S NEAR 80 OVER REST OF
CWA.
EDGE OF UPPER RIDGE DRAWS CLOSE ENOUGH FRIDAY NIGHT INTO SATURDAY TO
BRING SHRA/TSRA POSSIBILITY BACK TO THE AREA...ADVECTING IN FM
NORTHERN PLAINS WITH SW MEAN LAYER H85-H3 WINDS. EDGE OF MUCAPE OVER
1000J/KG AS CLOSE AS NORTHERN MN AND NORTHERN WI. ECMWF AND GFS ALSO
BOTH SHOWING SHORTWAVE CURRENTLY OVER FOUR CORNERS TRACKING OVER
NORTHERN MN AND LK SUPERIOR BY 12Z SATURDAY. INCREASING H85 JET
RAMPS UP MOISTURE ADVECTION OVER MN SO HAVE PUT CHANCE POPS OVER
WESTERN LK SUPERIOR ON FRIDAY NIGHT AND SPREAD THEM INTO FAR WEST
CWA ON SATURDAY AS THERE MAY BE GREATER CHANCE OF SHRA/TSRA IN VCNTY
OF THE SHORTWAVE AND GIVEN THE HIGHER MUCAPES. MLCAPES ALSO PUSH UP
TOWARD 1000J/KG DURING AFTN SO THERE MAY BE ADDITIONAL SHRA/TSRA TRY
TO FORM DUE TO DAYTIME HEATING AND POSSIBLY AFFECTS FM THE
SHORTWAVE. PROBABLY WILL BE SOME FOG AROUND TO START DAY AGAIN. SE
WINDS ADDING MOISTURE OFF LK MICHIGAN AND RADIATIONAL COOLING FRIDAY
NIGHT SHOULD LEAD TO BEST BET FOR FOG OVER INTERIOR CNTRL AND NEAR
LK MICHIGAN. ONCE FOG EVADES...PARTLY SUNNY SKIES WILL ALLOW TEMPS
TO WARM QUITE A BIT OVER FRIDAY. H85 TEMPS PUSHING 19-20C BY AFTN
AND MORE OF A SOUTH WIND COMPARED TO FRIDAY POINT TO MID-UPR 80S FOR
MOST WITH A FEW 90 DEGREE READINGS POSSIBLE INTERIOR WEST AND NEAR
LK SUPERIOR WITH DOWNSLOPING WINDS.
STRONGER SHORTWAVE LIFTS OVER UPPER MISSISSIPPI RIVER VALLEY SAT
NIGHT IN SW FLOW ALOFT. AT SFC...LOW PRESSURE SYSTEM WILL BE
DEVELOPING OVER HIGH PLAINS WHILE TROUGHING EXTENDS ACROSS NORTHERN
PLAINS AND TO NORTHWEST ONTARIO. SOUTH WINDS AHEAD OF TROUGH SHOULD
LEAD TO WARM/MUGGY NIGHT OVER UPR MICHIGAN. MUCAPES REMAIN HIGH AT
1000-2000J/KG FM NORTHERN PLAINS ACROSS UPPER GREAT LAKES. IF
SHORTWAVE TRACKS CLOSE ENOUGH...COULD SEE SHRA/TSRA PUSH OVER WEST
HALF OF CWA AT LEAST WITH H85-H3 WINDS FM THE WSW. UNLIKE FRIDAY
NIGHT WITH SIMILAR SETUP...SHEAR IS FORECAST TO BE MUCH STRONGER AS
1-6KM SHEAR VALUES ARE 30-40 KTS. LOW-LEVEL JET AT H85 OVER 40 KTS
IS AIMED TOWARD UPPER MISSISSIPPI RIVER VALLEY AND AT LEAST WESTERN
FRINGE OF UPPER GREAT LAKES. NOT SURE IF GREATER MLCAPES WELL TO SW
OF HERE WILL KEEP MAIN SHRA/TSRA THERE SINCE THE SHORTWAVE IS MUCH
FARTHER NORTH. CARRIED CHANCE POPS OVER WEST CWA...SLIGHT CHANCES
FARTHER EAST. GIVEN THE SHEAR AND INSTABILITY...THERE IS AT LEAST A
REMOTE CHANCE OF STRONG TO SEVERE STORMS AS SHOWN BY LATEST DAY3
OUTLOOK FM SPC.
STRONG SHORTWAVE SLIDES FM ROCKIES TO THE NORTHERN PLAINS SUNDAY
INTO SUNDAY NIGHT. ASSOCIATED SFC LOW BOTTOMS OUT AT 990-1000MB OVER
SOUTHERN MANITOBA BY MONDAY MORNING. MOISTURE ADVECTION AND
CONTINUAL FEED OF STRONG INSTABILITY SHOULD SUPPORT MULTIPLE CLUSTERS
OF SHRA/TSRA WITHIN H85 JET AXIS AND JUST AHEAD OF SFC FRONT. NEVER
SURE HOW FAR SHRA/TSRA WILL BREAK OUT AHEAD OF MAIN FRONT AS WITHOUT
STRONG FORCING FM A YET TO BE DETERMINED SHORTWAVE THERE CAN ALWAYS
BE CAPPING CONCERNS. WILL CONTINUE TO HIGHLIGHT WEST CWA FOR BETTER
CHANCES AT THIS POINT WITH WSW MEAN LAYER WINDS. ANOTHER WARM AND
HUMID DAY AHEAD OF THE FRONT. H85 RIDGE AHEAD OF THE FRONT POINTS TO
READINGS SIMILAR TO SAT AS LONG AS CLOUDS/SHRA/TSRA DONT DISRUPT
THINGS TOO MUCH. PUT THE WARMEST TEMPS ON SUNDAY OVER CNTRL CWA
CLOSER TO LK SUPERIOR WITH DOWNSLOPING SOUTH WINDS. BEST CHANCE FOR
READINGS TO HIT 90 DEGREES WOULD BE BARAGA/BIG
BAY/MARQUETTE/HARVEY/MUNISING.
ALL THIS SHRA/TSRA ACTIVITY SHOULD EASE EAST ACROSS REST OF CWA AS
THE MAIN SFC-H85 FRONTS AND ASSOCIATED THETA-E RIDGE AND RIBBON OF
PWATS OVER 1.75 INCHES CROSS SUNDAY NIGHT INTO MONDAY. MLCAPES OVER
1000J/KG INITIALLY BUT THESE TAIL OFF WITH NIGHTTIME COOLING.
MUCAPES WELL OVER 1000J/KG MAY ALLOW STORMS TO TRY TO BECOME
ELEVATED AFTER BECOMING SFC BASED...BUT THAT IS ALWAYS A TRICKY
TRANSITION. STRONG H85 JET AND MOISTURE TRANSPORT INTO THE AREA
OF HIGHER MUCAPES WILL AID THIS TRANSITION THOUGH. CONSENSUS HIGH
CHANCE TO LOW-END LIKELY POPS SEEMED FINE FOR SUNDAY NIGHT. BETTER
POPS ON LABOR DAY END UP BEING OVER EAST HALF WITH GREATER MOISTURE
ADVECTION AHEAD OF THE EXITING SFC-H85 FRONT. H85 TEMPS DO NOT CRASH
DOWN AS IT LOOKED LIKE A FEW DAYS AGO...SO UPR 70S TO LOW OR
POSSIBLY MID 80S WILL WORK FOR TEMPS ON MONDAY. WARMEST READINGS
CNTRL CWA IRON MTN TO MARQUETTE AND MUNISING. THROUGH THE COOLING IS
NOT AS SIGNIFICANT...THE DRYING IS WITH DWPNTS FALLING OFF INTO THE
50S ON MONDAY AFTN OVER THE WEST AND DOWN TO AROUND 50 BY LATE
MONDAY NIGHT. COULD EVEN SEE 40S DWPNTS ON TUESDAY AS COOLING
BECOMES MORE PRONOUNCED. EXPECT HIGHS UPR 60S TO LOW 70S ON TUE AND
THEN MAINLY IN THE 60S FOR WED. GUSTY WINDS AS THE COOLING OCCURS
ESPECIALLY NEAR LK SUPERIOR. NEXT CHANCE OF RAIN PRETTY WELL AGREED
UPON BY GFS AND ECMWF FOR TUE NIGHT INTO WED MORNING.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 324 AM EDT THU SEP 3 2015
LIFR/VLIFR CONDITIONS IN FOG ARE EXPECTED AT KIWD/KCMX/KSAW
OVERNIGHT DUE TO WET GROUND FROM RECENT RAIN...LIGHT WINDS AND
CLOUDS THINNING OUT. FOG/STRATUS WILL CLEAR OUT WITHIN A FEW HRS
AFTER SUNRISE...LEADING TO VFR CONDITIONS THRU THE AFTN AT ALL
TERMINALS. MAY HAVE A RETURN OF SOME FOG TONIGHT...PROBABLY JUST
BEYOND THIS FCST PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 412 AM EDT THU SEP 3 2015
DENSE FOG HAS DEVELOPED ACROSS THE WESTERN HALF OF THE
LAKE...ESPECIALLY OVER AREAS THAT SAW RAIN YESTERDAY. AS SUCH...HAVE
ISSUED A DENSE FOG ADVY FOR THE ENTIRE WEST HALF OF THE LAKE THROUGH
EARLY THIS AFTERNOON. 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...
DENSE FOG ADVISORY UNTIL 10 AM EDT /9 AM CDT/ THIS MORNING FOR
MIZ001>003-009-084.
LAKE SUPERIOR...
DENSE FOG ADVISORY UNTIL 2 PM EDT /1 PM CDT/ THIS AFTERNOON FOR
LSZ162-240>248-263>265.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...MRD
LONG TERM...JLA
AVIATION...ROLFSON
MARINE...MRD
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
413 AM EDT THU SEP 3 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 412 AM EDT THU SEP 3 2015
THE RAIN OVER THE SOUTHERN AND EASTERN PART OF THE FORECAST AREA
FINALLY SEEMS TO BE MOVING OUT OF THE AREA AS THE UPPER SHORT WAVE
MOVES EAST. THE BIG PROBLEM THIS MORNING IS ACTUALLY DENSE FOG
ACROSS THE WESTERN PART OF THE FORECAST AREA WHERE IT HAS CLEARED
OUT WITH SUFFICIENT LOW LEVEL MOISTURE FROM RAINFALL OVER THE PAST
24 HR. MOST OF THE WESTERN TIER OF COUNTIES HAVE VSBYS LESS THAN ONE
QUARTER OF A MILE AND AS SUCH HAVE OPTED TO GO WITH A DENSE FOG
ADVISORY FOR THIS AREA UNTIL 14Z.
OTHERWISE...AS THE UPPER SHORT WAVE SLOWLY MOVES EAST THIS
MORNING...EXPECT ANY REMAINING SHOWERS TO MOVE OUT OF THE AREA AS
WELL. THE RAP SUGGESTS THAT CYCLONIC FLOW WILL PERSIST THROUGH THE
DAY ACROSS THE EAST. THIS COMBINED WITH LAKE BREEZE CONVERGENCE
ACROSS THE EAST IMPLIES AT LEAST A SLIGHT CHANCE OF SHOWERS THIS
AFTERNOON ACROSS THE FAR EAST. NOT TOO EXCITED ABOUT THUNDERSTORM
CHANCES AS LOCAL RESEARCH SUGGESTS VERY MIMINAL THUNDERSTORM
DEVELOPMENT WITH NORTHERLY MID LEVEL FLOW. ACROSS THE REMAINDER OF
THE AREA...MINIMAL MLCAPE VALUES OF LESS THAN 300 J/KG PER THE
RAP...DRY AIR ASSOCIATED WITH THE HIGH PRES AND BUILDING HEIGHTS
SHOULD PRECLUDE ANY SHOWER/THUNDERSTORM DEVELOPMENT. DESPITE THE
NORTH-NORTHEAST FLOW...IT WILL STILL REMAIN MILD AND RATHER STICKY
WITH HIGHS IN THE UPPER 70S/LOWER 80S...STILL ABOVE NORMAL FOR EARLY
SEPTEMBER.
WITH HIGH PRESSURE IN CONTROL...IT SHOULD BE A QUIET NIGHT TONIGHT.
CANNOT RULE OUT MORE FOG DEVELOPMENT ACROSS THE INTERIOR WITH LIGHT
WINDS AND CLEAR SKIES. TEMPS SHOULD DROP INTO THE UPPER 50S/LOWER
60S.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 318 PM EDT WED SEP 2 2015
SPENT MOST TIME HELPING WITH SHORT TERM WARNING OPERATIONS...SO
RELIED HEAVILY ON PREVIOUS FORECAST AND CONSENSUS FOR THE LONG TERM
FORECAST.
OVERALL...EXPECT A SOME LOW END SHOWER AND THUNDERSTORM CHANCES IN
THE REGION FRI AND SAT AS THE UPPER RIDGE SITS OVER THE AREA WITH
SHORTWAVES PUSHING THROUGH THE RIDGE. A LOW PRESSURE SYSTEM WILL
MOVE FROM THE INTER-MOUNTAIN WEST LATE SAT TO HUDSON BAY BY
TUE...BRINGING INCREASED SHOWER AND THUNDERSTORM CHANCES SUN THROUGH
MON AS A COLD FRONT MOVES ACROSS. THE PROLONGED HEAT WILL GIVE WAY
TO COOLER TEMPS EARLY NEXT WEEK WHEN HIGH TEMPS WILL DROP DOWN
CLOSER TO NORMAL IN THE 60S AND 70S. ANOTHER SYSTEM MAY MOVE THROUGH
NEXT WED...POSSIBLY BRINGING PRECIP TO MUCH OF THE AREA...BUT
PREDICTABILITY IS LOW WITH THIS SYSTEM.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 324 AM EDT THU SEP 3 2015
LIFR/VLIFR CONDITIONS IN FOG ARE EXPECTED AT KIWD/KCMX/KSAW
OVERNIGHT DUE TO WET GROUND FROM RECENT RAIN...LIGHT WINDS AND
CLOUDS THINNING OUT. FOG/STRATUS WILL CLEAR OUT WITHIN A FEW HRS
AFTER SUNRISE...LEADING TO VFR CONDITIONS THRU THE AFTN AT ALL
TERMINALS. MAY HAVE A RETURN OF SOME FOG TONIGHT...PROBABLY JUST
BEYOND THIS FCST PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 412 AM EDT THU SEP 3 2015
DENSE FOG HAS DEVELOPED ACROSS THE WESTERN HALF OF THE
LAKE...ESPECIALLY OVER AREAS THAT SAW RAIN YESTERDAY. AS SUCH...HAVE
ISSUED A DENSE FOG ADVY FOR THE ENTIRE WEST HALF OF THE LAKE THROUGH
EARLY THIS AFTERNOON. 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...
DENSE FOG ADVISORY UNTIL 10 AM EDT /9 AM CDT/ THIS MORNING FOR
MIZ001>003-009-084.
LAKE SUPERIOR...
DENSE FOG ADVISORY UNTIL 2 PM EDT /1 PM CDT/ THIS AFTERNOON FOR
LSZ162-240>248-263>265.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...MRD
LONG TERM...TITUS
AVIATION...ROLFSON
MARINE...MRD
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
826 PM CDT FRI SEP 4 2015
.UPDATE...
OVERALL SIMILAR FORECAST TO LAST NIGHT. AIRMASS HAS NOT CHANGED MUCH
OVERALL IN THE LAST 24 HOURS AS PW`S ARE IN THE 1.7 INCH RANGE WITH
MORE MOISTURE ALONG THE COAST AND DRIER CONDITIONS TO THE N/E.
THEREFORE...WOULD NOT RULE OUT SOME PATCHY FOG/LOW CLOUDS IN S/SE MS
OVERNIGHT AS WE HAD THIS MORNING. HRRR ISN`T HINTING AS MUCH FOR MORE
WIDESPREAD PATCHY FOG SO KEPT IT OUT OF THE GRIDS OVERNIGHT. OVERALL
ADJUSTED POPS TO ACCOUNT FOR CHANCES FOR SHOWERS IN CENTRAL/SE MS FOR
NEXT FEW HOURS UNTIL 03Z. BASED ON LOWS LAST NIGHT AND CURRENT
DEWPOINT TRENDS...ADJUSTED LOWS SLIGHTLY. QUIET NIGHT IS IN STORE
WITH HIGH CLOUDS THINNING OVERNIGHT. /DC/
&&
.AVIATION...VFR CONDITIONS WILL PREVAIL FOR THE MOST PART THROUGH
SATURDAY...BUT EXPECT A REPEAT OF PATCHY MVFR CATEGORY FOG IN THE
09- 14Z TIME FRAME GIVEN LITTLE IN THE WAY OF AIRMASS CHANGE DURING
THE PAST 24 HRS. PER LATEST HRRR GUIDANCE...THE LIFR STRATUS/FOG
POTENTIAL IN THE HBG AREA DOESN`T LOOK QUITE AS GREAT AS IT WAS
EARLIER THIS MORNING...BUT IT WILL STILL BE SOMETHING TO CONSIDER.
OTHERWISE...AFTERNOON SHRA/TSRA COVERAGE WILL BE FAIRLY SPARSE AGAIN
SATURDAY...ESPECIALLY NORTH OF HBG AND HAVE LEFT ANY MENTION IN THE
TAFS. /EC/
&&
.PREV DISCUSSION... /ISSUED 434 PM CDT FRI SEP 4 2015/
DISCUSSION...NO BIG CHANGES TO THE FORECAST. THE PATTERN DOES NOT
APPEAR TO CHANGE UNTIL THE END OF NEXT WEEK WITH THE NEXT COLD FRONT.
STUCK WITH GUIDANCE TEMPS. WENT WITH A BLEND FOR POPS. THE GFS
KEPT THE BEST POPS IN SOUTH/SOUTHWEST...BUT BASED ON TODAY AND THE
VERY LITTLE CHANGE EXPECTED OVER THE NEXT FEW DAYS...THINKING CENTRAL
AND EAST MISSISSIPPI MAY GET A FEW SHOWERS AND THUNDERSTORMS ALSO.
WHILE THERE WILL BE AFTERNOON/EVENING CONVECTION EXPECTED EACH
DAY...INSTABILITY LOOKS LIMITED ACROSS THE AREA...SO THE HWO WILL
REMAIN CLEAR THROUGH THE SHORT TERM.
MODELS WERE CONSISTENT...KEEPING SUMMER GOING FOR THE NEXT WEEK.
SOUTHEAST WINDS BRING IN SOME MOISTURE...BUT AFTERNOON MIXING AND A
LIGHT BREEZE ALLOW TEMPERATURES TO CLIMB INTO THE MID TO UPPER 90S
FOR THE NEXT FEW DAYS. A FEW PLACES WERE NEAR 100 THIS AFTERNOON.
THE AREA SEEMS TO BE TRAPPED AN UPPER RIDGE TO THE WEST AND AN UPPER
LOW OVER THE NORTHERN GULF. AS THE SYSTEMS SHIFT BACK AND FORTH...MOVE
EAST AND RETROGRADE A TIME OR TWO...OVER THE NEXT FEW
DAYS...CONVECTION WILL INCREASE. BY MID WEEK...RAIN CHANCES WILL
INCREASE...MAINLY SOUTH OF INTERSTATE 20. THE UPPER LOW FINALLY GETS
PICKED UP THE FRONT AT THE END OF THE WEEK...BRINGING A COOLER/DRIER
AIR.
MODELS SUGGEST A WEAK WAVE WILL MOVE OUT OF THE GULF SATURDAY
AFTERNOON/EVENING WHICH SUPPORTS THE LARGE AREA OF CONVECTION GOING
THROUGH LATE SATURDAY. LEFT SMALL RAIN CHANCES IN ACROSS THE AREA FOR
SATURDAY NIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 73 95 72 94 / 13 24 19 31
MERIDIAN 71 94 69 91 / 11 22 19 25
VICKSBURG 72 96 69 94 / 10 23 19 27
HATTIESBURG 73 95 72 93 / 14 29 19 50
NATCHEZ 73 92 72 92 / 11 31 19 50
GREENVILLE 72 98 71 96 / 10 17 11 9
GREENWOOD 72 95 69 93 / 10 15 10 14
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
DC/EC
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1151 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 DEEPENING 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 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1147 PM CDT WED SEP 2 2015
UNLIMITED CEILING AND VISIBILITY ARE FORECAST TONIGHT...THURSDAY
AND THURSDAY AFTERNOON. SOUTHEAST WIND 5 TO 10 MPH TONIGHT WILL
INCREASE TO 12-14KT AND BECOME MORE SOUTH EARLY THURSDAY
AFTERNOON.
THE EVENING MODEL RUNS ARE SHOWING THUNDERSTORMS THURSDAY EVENING
AS A WEAK FRONT MAKES ITS WAY INTO WESTERN NEBRASKA. WEST OF VTN...
LBF...TIF AND CROSSING INTO CENTRAL NEBRASKA AFTER 06Z.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CLB
SHORT TERM...JWS
LONG TERM...CLB
AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1106 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 DEEPENING 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 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1104 PM CDT WED SEP 2 2015
UNLIMITED CEILING AND VISIBILITY ARE FORECAST TONIGHT...THURSDAY
AND THURSDAY EVENING. SOUTHEAST WIND 5 TO 10 MPH TONIGHT WILL
INCREASE TO 12-14KT AND BECOME MORE SOUTH EARLY THURSDAY
AFTERNOON.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CLB
SHORT TERM...JWS
LONG TERM...CLB
AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
742 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 725 PM EDT FRIDAY...FORECAST REMAINS IN GOOD SHAPE AND ONLY
NOMINAL ADJUSTMENTS NEEDED TO SKY COVER AND T/TD DATA TO SHORE UP
WITH CURRENT OBSERVATIONAL TRENDS. LOOKING AT A VERY PLEASANT
EVENING AS TEMPERATURES FALL INTO THE 50S AND 60S BY 900 PM.
PRIOR DISCUSSION FROM 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 /00Z SATURDAY THROUGH WEDNESDAY/...
THROUGH 00Z SUNDAY...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. EXPECTING SOME AREAS OF
IFR CONDITIONS FOR SLK/MPV OVERNIGHT DUE TO FOG AND BACK TO VFR
SHORTLY AFTER SUNRISE.
WINDS WILL BE LIGHT OUT OF THE NORTH OVERNIGHT AND SHIFTING TO
LIGHT OUT OF THE SOUTH BY MID MORNING.
OUTLOOK 00Z SUNDAY 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...JMG/TABER
SHORT TERM...TABER
LONG TERM...WGH
AVIATION...WGH/MV
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
725 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 725 PM EDT FRIDAY...FORECAST REMAINS IN GOOD SHAPE AND ONLY
NOMINAL ADJUSTMENTS NEEDED TO SKY COVER AND T/TD DATA TO SHORE UP
WITH CURRENT OBSERVATIONAL TRENDS. LOOKING AT A VERY PLEASANT
EVENING AS TEMPERATURES FALL INTO THE 50S AND 60S BY 900 PM.
PRIOR DISCUSSION FROM 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 /00Z SATURDAY 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...JMG/TABER
SHORT TERM...TABER
LONG TERM...WGH
AVIATION...WGH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
608 AM EDT THU SEP 3 2015
.SYNOPSIS...
ABOVE NORMAL TEMPERATURES ARE EXPECTED TODAY THROUGH FRIDAY. A WEAK
TROUGH WILL LINGER IN THE AREA THROUGH EARLY FRIDAY. A RIDGE OF HIGH
PRESSURE WILL BUILD IN FROM THE NORTH BEHIND A COLD FRONT THIS
WEEKEND...BRINGING UNSETTLED WEATHER AND COOLER TEMPERATURES THROUGH
THE FIRST PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 615 AM THURSDAY...LAST OF THE CONVECTION IS NOW MOVING
OFFSHORE NORTHERN PENDER COUNTY. THAT SHOULD END THE THUNDERSTORM
THREAT...REMOTE THOUGH IT MAY HAVE BEEN...UNTIL THIS AFTERNOON.
PREVIOUS DISCUSSION FOLLOWS:
GUST FRONT FROM CONVECTION UP NORTH MOVING THROUGH OUR NORTH
CAROLINA COUNTIES AT THIS TIME. WINDS ARE NOT STRONG...BUT AT 5 TO
10 KTS ARE CREATING A NOTICEABLE WIND SHIFT. ASSOCIATED CONVECTION
STILL TO OUR NORTH BUT MAY SCRAPE PENDER COUNTY BEFORE MOVING
OFFSHORE.
WEAK PRESSURE PATTERN AND ABOVE-NORMAL TEMPERATURES CONTINUE FOR
ANOTHER DAY. PIEDMONT-STYLE THERMAL TROUGH TO OUR WEST STRENGTHENS
TODAY AND ALSO EXPECT THE DIURNALLY DRIVEN SEA BREEZE CIRCULATION TO
SET UP THIS AFTERNOON. A MODERATELY UNSTABLE COLUMN WILL DEVELOP
THIS AFTERNOON AND WITH PLENTIFUL AVAILABLE MOISTURE...WITH P/W
VALUES CLOSING IN ON 2 INCHES...STILL EXPECTING SCATTERED CONVECTION
TO DEVELOP. INITIAL FOCUS OF CONVECTION...FOR LACK OF AN OTHER
STRONG TRIGGERS...WILL BE ALONG THE SEA BREEZE FRONT THIS AFTERNOON.
DIURNALLY DRIVEN CONVECTION WILL FADE WITH THE SUNSET.
ABOVE NORMAL TEMPERATURES WILL CONTINUE AND WITH DEWPOINTS RANGING
FROM THE UPPER 60S TO MID 70S EXPECT APPARENT TEMPERATURES TO PEAK
AT AROUND 100 DEGREES THIS AFTERNOON. OVERNIGHT MINIMUMS PROJECTED
IN THE LOWER TO MID 70S.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 230 AM THURSDAY...H5 RIDGE AXIS IS SHOWN TO EXTEND FROM THE
SOUTHERN PLAINS AND LOWER MS VALLEY INTO THE MID WEST AND GREAT
LAKES REGION EARLY FRIDAY WITH A WEAK TROUGH ORIENTED NEARLY EAST-
WEST FROM THE MID-ATLANTIC REGION TOWARD THE OHIO VALLEY. THE H5
TROUGH WILL DRIFT SOUTH ACROSS THE SOUTHEASTERN STATES WITH SOME
DURING SATURDAY AS HIGH PRESSURE ALOFT EVOLVES ACROSS NEW ENGLAND.
AT THE SURFACE...A RIDGE WILL BUILD SOUTH ACROSS THE FORECAST AREA
FRIDAY NIGHT INTO SATURDAY BRINGING AN END TO THE ATYPICALLY WARM
TEMPERATURES. THE PRECIPITABLE WATER DOES NOT STAND OUT AS IT IS
EXPECTED TO AVERAGE A LITTLE OVER AN INCH AND A HALF EACH DAY. AN
INCREASE IN LOW-LEVEL CONVERGENCE ON SATURDAY IN NORTHEASTERLY FLOW
TRANSLATES TO SLIGHTLY HIGHER POPS COMPARED TO FRIDAY IN AN
ENVIRONMENT THAT IS UNSETTLED...BUT DEVOID OF A SIGNIFICANT LIFTING
MECHANISM.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 230 AM THURSDAY...WEAK/BROAD AREA OF LOW PRESSURE NOTED IN
500MB PROGS WILL LINGER OVER THE SOUTHEAST UNITED STATES SUNDAY
RESULTING IN A CONTINUATION OF UNSETTLED WEATHER THROUGH TUESDAY AS
IT GRADUALLY WEAKENS OVER THE REGION. THE SURFACE RIDGE WEAKENS
ACROSS THE CAROLINAS AS WELL DURING THE PERIOD WITH LOWER PRESSURE
LINGERING OFF THE COAST. ALTHOUGH THE PRECIPITABLE WATER IS EXPECTED
TO INCREASE TO JUST UNDER TWO INCHES BY MONDAY THE HIGHEST
PRECIPITABLE WATER WILL CONTINUE TO BE SUPPRESSED OFFSHORE TO THE
SOUTHEAST AND SOUTH OF THE AREA. EXPECTING SCATTERED SHOWERS AND A
FEW TSTMS EACH DAY WITH THE BEST CHANCES MONDAY COINCIDENT WITH THE
HIGHEST PRECIPITABLE WATER. MAX TEMPERATURES EACH DAY WILL RANGE
WITHIN A COUPLE DEGREES OF CLIMATOLOGY WHILE THE MINS REMAIN A
COUPLE CATEGORIES ABOVE NORMAL.
&&
.AVIATION /10Z THURSDAY THROUGH MONDAY/...
AS OF 06Z...THE HRRR MODEL HAS BEEN FAIRLY CONSISTENT IN BRINGING
SOME CONVECTION FROM THE NORTHWEST...ASSOCIATED WITH A MODERATE
VORT MAX DROPPING IN FROM VIRGINIA. THE CONVECTION WILL LIKELY
DISSIPATE BY 10-11Z AS IT MOVES OFF THE COAST OF SOUTHEAST NORTH
CAROLINA. THIS IS MAINLY LEANING ON THE NAM MODEL AS THE GFS
SHIFTS THE PRECIP OFFSHORE BEFORE IT GETS HERE. TOOK OUT THE TEMPO
LOWER FOG AT LBT AS THERE WILL LIKELY BE TOO MANY CLOUDS TO
RADIATE EFFECTIVELY. THURSDAY...ANOTHER HOT DAY WITH WEST
NORTHWEST FLOW. SOME SCATTERED CONVECTION MAY DEVELOP AROUND MAX
HEATING...ESPECIALLY ALONG THE RESULTANT.
EXTENDED OUTLOOK...PREDOMINATELY VFR WITH BRIEF MORNING FOG AND
ISOLATED/SCATTERED AFTERNOON SHOWERS AND THUNDERSTORMS.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 615 AM THURSDAY...NO CHANGES TO THE FORECAST WITH THE LATEST
UPDATE. PREVIOUS DISCUSSION FOLLOWS:
A WEAK PRESSURE PATTERN OVER THE WESTERN ATLANTIC WILL MAINTAIN A
WESTERLY FLOW OF 10 KTS OVER THE COASTAL WATERS EARLY
TODAY...INCREASING TO 10 TO 15 KTS WITH HIGHER GUSTS NEAR SHORE
THIS AFTERNOON. WINDS WILL DECREASE BACK TO AROUND 10 KTS OR LESS
OVERNIGHT WHILE BECOMING MORE SOUTHWESTERLY. SEAS WILL STAY IN THE
2 FT RANGE THROUGH THE PERIOD.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 230 AM THURSDAY...LIGHT/VARIABLE WINDS EXPECTED WITH A WEAK
PRESSURE GRADIENT ACROSS THE WATERS FRIDAY THROUGH FRIDAY EVENING.
AS RIDGE OF HIGH PRESSURE BUILDS SOUTH INTO THE CAROLINAS EARLY
SATURDAY MORNING THE WIND WILL VEER TO THE NORTHEAST AND INCREASE TO
10 TO 15 KNOTS...POSSIBLY CLOSER TO 15 KNOTS ACROSS THE CAPE FEAR
WATERS FOR A BIT SATURDAY AFTERNOON/EVENING. SEAS WILL INCREASE TO
AROUND 3 FT OR A LITTLE HIGHER AS THE NORTHEAST WINDS INCREASE.
LONG TERM /SUNDAY THROUGH MONDAY/...
AS OF 230 AM THURSDAY...NORTHEAST WINDS WILL BEGIN TO WEAKEN DURING
SUNDAY AS THE RIDGE WEAKENS. COULD SEE ANOTHER PERIOD OF
LIGHT/VARIABLE WINDS DURING MONDAY WITH A WEAK PRESSURE GRADIENT
RETURNING TO THE AREA. SEAS AROUND 3 FT SUNDAY WILL SUBSIDE TO 2-3
FT DURING MONDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SRP
NEAR TERM...REK
SHORT TERM...SRP
LONG TERM...JDW/SRP
AVIATION...DL
MARINE...REK/SRP
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
326 AM EDT THU SEP 3 2015
.SYNOPSIS...
ABOVE NORMAL TEMPERATURES ARE EXPECTED TODAY THROUGH FRIDAY. A WEAK
TROUGH WILL LINGER IN THE AREA THROUGH EARLY FRIDAY. A RIDGE OF HIGH
PRESSURE WILL BUILD IN FROM THE NORTH BEHIND A COLD FRONT THIS
WEEKEND...BRINGING UNSETTLED WEATHER AND COOLER TEMPERATURES THROUGH
THE FIRST PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 330 AM THURSDAY...GUST FRONT FROM CONVECTION UP NORTH
MOVING THROUGH OUR NORTH CAROLINA COUNTIES AT THIS TIME. WINDS ARE
NOT STRONG...BUT AT 5 TO 10 KTS ARE CREATING A NOTICEABLE WIND
SHIFT. ASSOCIATED CONVECTION STILL TO OUR NORTH BUT MAY SCRAPE
PENDER COUNTY BEFORE MOVING OFFSHORE.
WEAK PRESSURE PATTERN AND ABOVE-NORMAL TEMPERATURES CONTINUE FOR
ANOTHER DAY. PIEDMONT-STYLE THERMAL TROUGH TO OUR WEST STRENGTHENS
TODAY AND ALSO EXPECT THE DIURNALLY DRIVEN SEA BREEZE CIRCULATION TO
SET UP THIS AFTERNOON. A MODERATELY UNSTABLE COLUMN WILL DEVELOP
THIS AFTERNOON AND WITH PLENTIFUL AVAILABLE MOISTURE...WITH P/W
VALUES CLOSING IN ON 2 INCHES...STILL EXPECTING SCATTERED CONVECTION
TO DEVELOP. INITIAL FOCUS OF CONVECTION...FOR LACK OF AN OTHER
STRONG TRIGGERS...WILL BE ALONG THE SEA BREEZE FRONT THIS AFTERNOON.
DIURNALLY DRIVEN CONVECTION WILL FADE WITH THE SUNSET.
ABOVE NORMAL TEMPERATURES WILL CONTINUE AND WITH DEWPOINTS RANGING
FROM THE UPPER 60S TO MID 70S EXPECT APPARENT TEMPERATURES TO PEAK
AT AROUND 100 DEGREES THIS AFTERNOON. OVERNIGHT MINIMUMS PROJECTED
IN THE LOWER TO MID 70S.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 230 AM THURSDAY...H5 RIDGE AXIS IS SHOWN TO EXTEND FROM THE
SOUTHERN PLAINS AND LOWER MS VALLEY INTO THE MID WEST AND GREAT
LAKES REGION EARLY FRIDAY WITH A WEAK TROUGH ORIENTED NEARLY EAST-
WEST FROM THE MID-ATLANTIC REGION TOWARD THE OHIO VALLEY. THE H5
TROUGH WILL DRIFT SOUTH ACROSS THE SOUTHEASTERN STATES WITH SOME
DURING SATURDAY AS HIGH PRESSURE ALOFT EVOLVES ACROSS NEW ENGLAND.
AT THE SURFACE...A RIDGE WILL BUILD SOUTH ACROSS THE FORECAST AREA
FRIDAY NIGHT INTO SATURDAY BRINGING AN END TO THE ATYPICALLY WARM
TEMPERATURES. THE PRECIPITABLE WATER DOES NOT STAND OUT AS IT IS
EXPECTED TO AVERAGE A LITTLE OVER AN INCH AND A HALF EACH DAY. AN
INCREASE IN LOW-LEVEL CONVERGENCE ON SATURDAY IN NORTHEASTERLY FLOW
TRANSLATES TO SLIGHTLY HIGHER POPS COMPARED TO FRIDAY IN AN
ENVIRONMENT THAT IS UNSETTLED...BUT DEVOID OF A SIGNIFICANT LIFTING
MECHANISM.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 230 AM THURSDAY...WEAK/BROAD AREA OF LOW PRESSURE NOTED IN
500MB PROGS WILL LINGER OVER THE SOUTHEAST UNITED STATES SUNDAY
RESULTING IN A CONTINUATION OF UNSETTLED WEATHER THROUGH TUESDAY AS
IT GRADUALLY WEAKENS OVER THE REGION. THE SURFACE RIDGE WEAKENS
ACROSS THE CAROLINAS AS WELL DURING THE PERIOD WITH LOWER PRESSURE
LINGERING OFF THE COAST. ALTHOUGH THE PRECIPITABLE WATER IS EXPECTED
TO INCREASE TO JUST UNDER TWO INCHES BY MONDAY THE HIGHEST
PRECIPITABLE WATER WILL CONTINUE TO BE SUPPRESSED OFFSHORE TO THE
SOUTHEAST AND SOUTH OF THE AREA. EXPECTING SCATTERED SHOWERS AND A
FEW TSTMS EACH DAY WITH THE BEST CHANCES MONDAY COINCIDENT WITH THE
HIGHEST PRECIPITABLE WATER. MAX TEMPERATURES EACH DAY WILL RANGE
WITHIN A COUPLE DEGREES OF CLIMATOLOGY WHILE THE MINS REMAIN A
COUPLE CATEGORIES ABOVE NORMAL.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
AS OF 06Z...THE HRRR MODEL HAS BEEN FAIRLY CONSISTENT IN BRINGING
SOME CONVECTION FROM THE NORTHWEST...ASSOCIATED WITH A MODERATE
VORT MAX DROPPING IN FROM VIRGINIA. THE CONVECTION WILL LIKELY
DISSIPATE BY 10-11Z AS IT MOVES OFF THE COAST OF SOUTHEAST NORTH
CAROLINA. THIS IS MAINLY LEANING ON THE NAM MODEL AS THE GFS
SHIFTS THE PRECIP OFFSHORE BEFORE IT GETS HERE. TOOK OUT THE TEMPO
LOWER FOG AT LBT AS THERE WILL LIKELY BE TOO MANY CLOUDS TO
RADIATE EFFECTIVELY. THURSDAY...ANOTHER HOT DAY WITH WEST
NORTHWEST FLOW. SOME SCATTERED CONVECTION MAY DEVELOP AROUND MAX
HEATING...ESPECIALLY ALONG THE RESULTANT.
EXTENDED OUTLOOK...PREDOMINATELY VFR WITH BRIEF MORNING FOG AND
ISOLATED/SCATTERED AFTERNOON SHOWERS AND THUNDERSTORMS.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 330 AM THURSDAY...A WEAK PRESSURE PATTERN OVER THE WESTERN
ATLANTIC WILL MAINTAIN A WESTERLY FLOW OF 10 KTS OVER THE COASTAL
WATERS EARLY TODAY...INCREASING TO 10 TO 15 KTS WITH HIGHER GUSTS
NEAR SHORE THIS AFTERNOON. WINDS WILL DECREASE BACK TO AROUND 10
KTS OR LESS OVERNIGHT WHILE BECOMING MORE SOUTHWESTERLY. SEAS WILL
STAY IN THE 2 FT RANGE THROUGH THE PERIOD.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 230 AM THURSDAY...LIGHT/VARIABLE WINDS EXPECTED WITH A WEAK
PRESSURE GRADIENT ACROSS THE WATERS FRIDAY THROUGH FRIDAY EVENING.
AS RIDGE OF HIGH PRESSURE BUILDS SOUTH INTO THE CAROLINAS EARLY
SATURDAY MORNING THE WIND WILL VEER TO THE NORTHEAST AND INCREASE TO
10 TO 15 KNOTS...POSSIBLY CLOSER TO 15 KNOTS ACROSS THE CAPE FEAR
WATERS FOR A BIT SATURDAY AFTERNOON/EVENING. SEAS WILL INCREASE TO
AROUND 3 FT OR A LITTLE HIGHER AS THE NORTHEAST WINDS INCREASE.
LONG TERM /SUNDAY THROUGH MONDAY/...
AS OF 230 AM THURSDAY...NORTHEAST WINDS WILL BEGIN TO WEAKEN DURING
SUNDAY AS THE RIDGE WEAKENS. COULD SEE ANOTHER PERIOD OF
LIGHT/VARIABLE WINDS DURING MONDAY WITH A WEAK PRESSURE GRADIENT
RETURNING TO THE AREA. SEAS AROUND 3 FT SUNDAY WILL SUBSIDE TO 2-3
FT DURING MONDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SRP
NEAR TERM...REK
SHORT TERM...SRP
LONG TERM...JDW/SRP
AVIATION...DL
MARINE...REK/SRP
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
230 AM EDT THU SEP 3 2015
.SYNOPSIS...
ABOVE NORMAL TEMPERATURES ARE EXPECTED TODAY THROUGH FRIDAY. A WEAK
TROUGH WILL LINGER IN THE AREA THROUGH EARLY FRIDAY. A RIDGE OF HIGH
PRESSURE WILL BUILD IN FROM THE NORTH BEHIND A COLD FRONT THIS
WEEKEND...BRINGING UNSETTLED WEATHER AND COOLER TEMPERATURES THROUGH
THE FIRST PART OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 130 AM THURSDAY...RADAR LOOPS AND OBS SHOW IMPRESSIVE GUST
FRONT DROPPING SOUTH INTO THE FORECAST AREA FROM STORM ACTIVITY TO
THE NORTH. EXPECT NO BIG IMPACTS...JUST A WIND SHIFT TO THE NORTH.
STILL POSSIBLE THAT WE COULD SEE SOME OF THIS CONVECTION TO THE
NORTH DROP INTO OUR NORTHERN TIER OF COUNTIES. PREVIOUS
DISCUSSIONS FOLLOW:
STORMS IN NORTHEASTERN NORTH CAROLINA HAS DEVELOPED A MASSED
OUTFLOW BOUNDARY PUSHING SOUTH THROUGH RALEIGH AND GREENVILLE AT
THIS TIME. A SECOND CLUSTER OF STORMS FROM ASHEBORO TO LEXINGTON
IS MOVING SOUTHEASTWARD. THIS OUTFLOW BOUNDARY IS SURPRISINGLY
DEEP...THE RALEIGH RADAR SHOWS THE BOUNDARY EXTENDING UP TO AROUND
7000 FEET NEAR GREENVILLE WHICH IS DEEP ENOUGH TO LIFT PARCELS AT
THE LFC. ODDS ARE STILL ABOUT 1-IN-4 TO 1-IN-5 CONVECTION WILL
SURVIVE ALL THE WAY DOWN TO LUMBERTON...ELIZABETHTOWN AND BURGAW.
A SMALL (20%) POP IS BEING MAINTAINED HERE AFTER MIDNIGHT.
OTHERWISE MOSTLY CLEAR SKIES WILL CONTINUE OVERNIGHT WITH LOWS
70-75. DISCUSSION FROM 730 PM FOLLOWS...
CLOSELY WATCHING SCATTERED CONVECTIVE SHOWERS AND STORMS ACROSS
THE NORTHWESTERN HALF OF NC SINKING SOUTHEASTWARD. WHILE THE 500
MB COLD POOL CENTERED OVER VIRGINIA SHOULD NOT DIVE THIS FAR
SOUTH...A SURPRISING NUMBER OF MODELS STILL SHOW SHOWERS MAKING IT
INTO SE NORTH CAROLINA STARTING AROUND 3-4 AM. FORECAST SOUNDINGS
SHOW THIS WOULD NOT BE SURFACE- BASED CONVECTION BUT INSTEAD
ROOTED IN A LAYER AROUND 7000 FEET UP. LAPSE RATES BETWEEN 800-400
MB ARE STEEP ENOUGH THAT SHOULD ANYTHING SURVIVE THAT LATE IT
COULD STILL HAVE THUNDER. TO BLEND WITH NWS RAH AND MHX I HAVE
ADDED A 20 POP LATE TONIGHT FROM LUMBERTON TO ELIZABETHTOWN TO
BURGAW...OTHERWISE VERY FEW CHANGES WERE NEEDED TO THE FORECAST
WITH THIS EARLY EVENING UPDATE.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 230 AM THURSDAY...H5 RIDGE AXIS IS SHOWN TO EXTEND FROM THE
SOUTHERN PLAINS AND LOWER MS VALLEY INTO THE MID WEST AND GREAT
LAKES REGION EARLY FRIDAY WITH A WEAK TROUGH ORIENTED NEARLY EAST-
WEST FROM THE MID-ATLANTIC REGION TOWARD THE OHIO VALLEY. THE H5
TROUGH WILL DRIFT SOUTH ACROSS THE SOUTHEASTERN STATES WITH SOME
DURING SATURDAY AS HIGH PRESSURE ALOFT EVOLVES ACROSS NEW ENGLAND.
AT THE SURFACE...A RIDGE WILL BUILD SOUTH ACROSS THE FORECAST AREA
FRIDAY NIGHT INTO SATURDAY BRINGING AN END TO THE ATYPICALLY WARM
TEMPERATURES. THE PRECIPITABLE WATER DOES NOT STAND OUT AS IT IS
EXPECTED TO AVERAGE A LITTLE OVER AN INCH AND A HALF EACH DAY. AN
INCREASE IN LOW-LEVEL CONVERGENCE ON SATURDAY IN NORTHEASTERLY FLOW
TRANSLATES TO SLIGHTLY HIGHER POPS COMPARED TO FRIDAY IN AN
ENVIRONMENT THAT IS UNSETTLED...BUT DEVOID OF A SIGNIFICANT LIFTING
MECHANISM.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 230 AM THURSDAY...WEAK/BROAD AREA OF LOW PRESSURE NOTED IN
500MB PROGS WILL LINGER OVER THE SOUTHEAST UNITED STATES SUNDAY
RESULTING IN A CONTINUATION OF UNSETTLED WEATHER THROUGH TUESDAY AS
IT GRADUALLY WEAKENS OVER THE REGION. THE SURFACE RIDGE WEAKENS
ACROSS THE CAROLINAS AS WELL DURING THE PERIOD WITH LOWER PRESSURE
LINGERING OFF THE COAST. ALTHOUGH THE PRECIPITABLE WATER IS EXPECTED
TO INCREASE TO JUST UNDER TWO INCHES BY MONDAY THE HIGHEST
PRECIPITABLE WATER WILL CONTINUE TO BE SUPPRESSED OFFSHORE TO THE
SOUTHEAST AND SOUTH OF THE AREA. EXPECTING SCATTERED SHOWERS AND A
FEW TSTMS EACH DAY WITH THE BEST CHANCES MONDAY COINCIDENT WITH THE
HIGHEST PRECIPITABLE WATER. MAX TEMPERATURES EACH DAY WILL RANGE
WITHIN A COUPLE DEGREES OF CLIMATOLOGY WHILE THE MINS REMAIN A
COUPLE CATEGORIES ABOVE NORMAL.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 06Z...THE HRRR MODEL HAS BEEN FAIRLY CONSISTENT IN BRINGING
SOME CONVECTION FROM THE NORTHWEST...ASSOCIATED WITH A MODERATE
VORT MAX DROPPING IN FROM VIRGINIA. THE CONVECTION WILL LIKELY
DISSIPATE BY 10-11Z AS IT MOVES OFF THE COAST OF SOUTHEAST NORTH
CAROLINA. THIS IS MAINLY LEANING ON THE NAM MODEL AS THE GFS
SHIFTS THE PRECIP OFFSHORE BEFORE IT GETS HERE. TOOK OUT THE TEMPO
LOWER FOG AT LBT AS THERE WILL LIKELY BE TOO MANY CLOUDS TO
RADIATE EFFECTIVELY. THURSDAY...ANOTHER HOT DAY WITH WEST
NORTHWEST FLOW. SOME SCATTERED CONVECTION MAY DEVELOP AROUND MAX
HEATING...ESPECIALLY ALONG THE RESULTANT.
EXTENDED OUTLOOK...PREDOMINATELY VFR WITH BRIEF MORNING FOG AND
ISOLATED/SCATTERED AFTERNOON SHOWERS AND THUNDERSTORMS.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 130 AM THURSDAY...ABSOLUTELY NO CHANGES WERE NEEDED TO THE
FORECAST WITH THIS LATEST EVENING UPDATE. DISCUSSION FROM 300 PM
FOLLOWS...
A TROUGH WILL BE STRUNG OUT FROM WEST TO EAST SOUTH OF OUR LOCAL
WATERS BUT WEAK HIGH PRESSURE WILL HOLD LOCALLY THROUGH TODAY.
BASICALLY FLOW WILL BE DOMINATED BY THE SEA BREEZE THIS AFTERNOON
WITH ON SHORE GUSTIER WINDS...BASICALLY SE-S. WITH WINDS GENERALLY
10 KT OR LESS...SEAS WILL REMAIN 2 FT OR LESS.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 230 AM THURSDAY...LIGHT/VARIABLE WINDS EXPECTED WITH A WEAK
PRESSURE GRADIENT ACROSS THE WATERS FRIDAY THROUGH FRIDAY EVENING.
AS RIDGE OF HIGH PRESSURE BUILDS SOUTH INTO THE CAROLINAS EARLY
SATURDAY MORNING THE WIND WILL VEER TO THE NORTHEAST AND INCREASE TO
10 TO 15 KNOTS...POSSIBLY CLOSER TO 15 KNOTS ACROSS THE CAPE FEAR
WATERS FOR A BIT SATURDAY AFTERNOON/EVENING. SEAS WILL INCREASE TO
AROUND 3 FT OR A LITTLE HIGHER AS THE NORTHEAST WINDS INCREASE.
LONG TERM /SUNDAY THROUGH MONDAY/...
AS OF 230 AM THURSDAY...NORTHEAST WINDS WILL BEGIN TO WEAKEN DURING
SUNDAY AS THE RIDGE WEAKENS. COULD SEE ANOTHER PERIOD OF
LIGHT/VARIABLE WINDS DURING MONDAY WITH A WEAK PRESSURE GRADIENT
RETURNING TO THE AREA. SEAS AROUND 3 FT SUNDAY WILL SUBSIDE TO 2-3
FT DURING MONDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...REK
SHORT TERM...SRP
LONG TERM...SRP
AVIATION...DL/REK
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
143 AM EDT THU SEP 3 2015
.SYNOPSIS...
ABOVE NORMAL TEMPERATURES ARE EXPECTED THROUGH FRIDAY. A WEAK
TROUGH WILL LINGER IN THE AREA THROUGH EARLY FRIDAY. A RIDGE OF
HIGH PRESSURE WILL BUILD IN FROM THE NORTH BEHIND A COLD FRONT BY
THIS WEEKEND...BRINGING UNSETTLED WEATHER AND COOLER TEMPERATURES
THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 130 AM THURSDAY...RADAR LOOPS AND OBS SHOW IMPRESSIVE GUST
FRONT DROPPING SOUTH INTO THE FORECAST AREA FROM STORM ACTIVITY TO
THE NORTH. EXPECT NO BIG IMPACTS...JUST A WIND SHIFT TO THE NORTH.
STILL POSSIBLE THAT WE COULD SEE SOME OF THIS CONVECTION TO THE
NORTH DROP INTO OUR NORTHERN TIER OF COUNTIES. PREVIOUS
DISCUSSIONS FOLLOW:
STORMS IN NORTHEASTERN NORTH CAROLINA HAS DEVELOPED A MASSED
OUTFLOW BOUNDARY PUSHING SOUTH THROUGH RALEIGH AND GREENVILLE AT
THIS TIME. A SECOND CLUSTER OF STORMS FROM ASHEBORO TO LEXINGTON
IS MOVING SOUTHEASTWARD. THIS OUTFLOW BOUNDARY IS SURPRISINGLY
DEEP...THE RALEIGH RADAR SHOWS THE BOUNDARY EXTENDING UP TO AROUND
7000 FEET NEAR GREENVILLE WHICH IS DEEP ENOUGH TO LIFT PARCELS AT
THE LFC. ODDS ARE STILL ABOUT 1-IN-4 TO 1-IN-5 CONVECTION WILL
SURVIVE ALL THE WAY DOWN TO LUMBERTON...ELIZABETHTOWN AND BURGAW.
A SMALL (20%) POP IS BEING MAINTAINED HERE AFTER MIDNIGHT.
OTHERWISE MOSTLY CLEAR SKIES WILL CONTINUE OVERNIGHT WITH LOWS
70-75. DISCUSSION FROM 730 PM FOLLOWS...
CLOSELY WATCHING SCATTERED CONVECTIVE SHOWERS AND STORMS ACROSS
THE NORTHWESTERN HALF OF NC SINKING SOUTHEASTWARD. WHILE THE 500
MB COLD POOL CENTERED OVER VIRGINIA SHOULD NOT DIVE THIS FAR
SOUTH...A SURPRISING NUMBER OF MODELS STILL SHOW SHOWERS MAKING IT
INTO SE NORTH CAROLINA STARTING AROUND 3-4 AM. FORECAST SOUNDINGS
SHOW THIS WOULD NOT BE SURFACE- BASED CONVECTION BUT INSTEAD
ROOTED IN A LAYER AROUND 7000 FEET UP. LAPSE RATES BETWEEN 800-400
MB ARE STEEP ENOUGH THAT SHOULD ANYTHING SURVIVE THAT LATE IT
COULD STILL HAVE THUNDER. TO BLEND WITH NWS RAH AND MHX I HAVE
ADDED A 20 POP LATE TONIGHT FROM LUMBERTON TO ELIZABETHTOWN TO
BURGAW...OTHERWISE VERY FEW CHANGES WERE NEEDED TO THE FORECAST
WITH THIS EARLY EVENING UPDATE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/...
AS OF 300 PM WEDNESDAY...UPPER RIDGE BUILDS STRONGLY ACROSS MIDDLE
AMERICA AND THIS WILL RESULT IN A TROUGH DIGGING DOWN THE EAST
COAST THU INTO FRI. DEVELOPING NW FLOW ALOFT WILL ALLOW WEAK MID-
LEVEL DISTURBANCES...EMBEDDED IN FLOW...TO IMPACT THE EASTERN
CAROLINAS. THE STRONGEST OF THESE FEATURES DURING THIS TIME FRAME
WILL REACH THE AREA LATER THU AFTERNOON AND THU NIGHT. AT THE
SURFACE...HIGH PRESSURE WILL ASSERT A STRONG ENOUGH PUSH TO BRING
A BACKDOOR COLD FRONT ACROSS THE AREA FRIDAY NIGHT. THE PIEDMONT
TROUGH AND SEABREEZE BOUNDARIES WILL STRENGTHEN THU AFTERNOON AND
THESE MESOSCALE BOUNDARIES SHOULD PROVIDE SOME MODEST LIFT...THUS
ALLOWING SOME CONVECTION TO DEVELOP AS STRONG HEATING INCREASES
THE INSTABILITY.
THE HIGHEST PRECIPITABLE WATER VALUES AND THE GREATEST MOISTURE
DEPTH ARE STILL EXPECTED THU/THU NIGHT...ALTHOUGH NOT THAT
IMPRESSIVE EVEN FOR EARLY SEPTEMBER. AT THIS TIME...WILL KEEP
POPS IN THE SLIGHT CHANCE/CHANCE CATEGORY. HOWEVER...HIGHER POPS
MAY BE WARRANTED AS WE PROGRESS THROUGH LATE WEEK AND ARE BETTER
ABLE TO NAIL DOWN THE TIMING OF THE VARIOUS FEATURES PREVIOUSLY
DISCUSSED.
THE WARMEST DAY WILL BE THU WHEN HIGHS ARE EXPECTED MAINLY IN THE
MID 90S WITH LOWER 90S VERY NEAR THE COAST AND UPPER 80S AT THE
BEACHES. HIGHS ON FRI WILL BE MAINLY IN THE LOWER 90S...STILL ABOVE
NORMAL...UPPER 80S AT THE BEACHES. LOWS WILL BE IN THE LOWER 70S THU
NIGHT AND UPPER 60S TO LOWER 70S FRI NIGHT.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 300 PM WEDNESDAY...COMPLEX MID-LEVEL PATTERN WILL LEAD TO A
CHALLENGING FORECAST WITH LIKELY AN EXTENDED PERIOD OF UNSETTLED
WEATHER ACROSS THE SOUTHEAST. GFS AND ECMWF ARE IN PRETTY GOOD
AGREEMENT THROUGH THE EXTENDED WHICH CREATES HIGHER CONFIDENCE THIS
PERIOD...AND IT APPEARS MUCH OF THE EXTENDED WILL BE UNSETTLED WITH
BELOW NORMAL HIGHS AND SEASONABLE LOWS.
LARGE UPPER RIDGE WILL BUILD ACROSS THE NORTHEAST FROM THE GULF
COAST...DRIVING A SURFACE RIDGE DOWN THE EASTERN SEABOARD. AS THIS
OCCURS...A BACK DOOR TYPE FRONT WILL STALL SOUTH OF THE AREA...AS A
WEAKNESS IN THE PRESSURE FIELD STRENGTHENS AND EXPANDS FROM THE
NE...SOUTH OF THE RIDGE. THIS UPPER TROUGH WILL SHARPEN AND CUT OFF
ACROSS THE SOUTHEAST...AND THEN SIT BASICALLY IN PLACE THROUGH
TUESDAY AS IT IS BLOCKED BY RIDGING ON ALL SIDES. BENEATH THIS
TROUGH...THE REMNANTS OF ERIKA WILL MEANDER NEAR THE SOUTHEAST COAST
MAINTAINING CLOUDS...SHOWERS...AND COOL TEMPERATURES...ESPECIALLY
ALONG THE COAST. STILL SOME UNCERTAINTY INTO HOW MUCH QPF IS
EXPECTED SINCE FORCING IS WEAK...BUT TROPICAL MOISTURE IN THE
VICINITY OF ERIKAS REMNANTS WILL CREATE THE POTENTIAL FOR
SHOWERS...SOME OF WHICH MAY BE HEAVY AT TIMES...ESPECIALLY SUNDAY
THROUGH TUESDAY. WPC QPF SHOWS 1-2 INCHES THROUGH THE
PERIOD...HEAVIEST ALONG THE COAST. GUIDANCE SUGGESTS ERIKAS REMNANTS
WILL FINALLY DISSIPATE ENTIRELY BY WEDNESDAY AND LIFT TO THE NORTH
AS THE BLOCKING RIDGE WEAKENS...THIS WILL LEAD TO IMPROVING AND MORE
SEASONABLE WEATHER AT THE END OF THE EXTENDED.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 06Z...THE HRRR MODEL HAS BEEN FAIRLY CONSISTENT IN BRINGING
SOME CONVECTION FROM THE NORTHWEST...ASSOCIATED WITH A MODERATE
VORT MAX DROPPING IN FROM VIRGINIA. THE CONVECTION WILL LIKELY
DISSIPATE BY 10-11Z AS IT MOVES OFF THE COAST OF SOUTHEAST NORTH
CAROLINA. THIS IS MAINLY LEANING ON THE NAM MODEL AS THE GFS
SHIFTS THE PRECIP OFFSHORE BEFORE IT GETS HERE. TOOK OUT THE TEMPO
LOWER FOG AT LBT AS THERE WILL LIKELY BE TOO MANY CLOUDS TO
RADIATE EFFECTIVELY. THURSDAY...ANOTHER HOT DAY WITH WEST
NORTHWEST FLOW. SOME SCATTERED CONVECTION MAY DEVELOP AROUND MAX
HEATING...ESPECIALLY ALONG THE RESULTANT.
EXTENDED OUTLOOK...PREDOMINATELY VFR WITH BRIEF MORNING FOG AND
ISOLATED/SCATTERED AFTERNOON SHOWERS AND THUNDERSTORMS.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 130 AM THURSDAY...ABSOLUTELY NO CHANGES WERE NEEDED TO THE
FORECAST WITH THIS LATEST EVENING UPDATE. DISCUSSION FROM 300 PM
FOLLOWS...
A TROUGH WILL BE STRUNG OUT FROM WEST TO EAST SOUTH OF OUR LOCAL
WATERS BUT WEAK HIGH PRESSURE WILL HOLD LOCALLY THROUGH TODAY.
BASICALLY FLOW WILL BE DOMINATED BY THE SEA BREEZE THIS AFTERNOON
WITH ON SHORE GUSTIER WINDS...BASICALLY SE-S. WITH WINDS GENERALLY
10 KT OR LESS...SEAS WILL REMAIN 2 FT OR LESS.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 PM WEDNESDAY...THE SLACK PRESSURE GRADIENT...WHICH HAS
BEEN IN PLACE FOR SEVERAL DAYS...WILL FINALLY BEGIN TO TIGHTEN...
AND WITH THAT WE WILL SEE WIND SPEEDS INCREASING. THE HIGHEST
WINDS THIS PERIOD ARE EXPECTED IN THE WAKE OF A BACKDOOR COLD
FRONT FRI NIGHT. WIND SPEEDS FRI NIGHT ARE EXPECTED TO BE UP TO 15
TO 20 KT AS A NE SURGE EXPANDS SOUTHWARD ACROSS THE WATERS AS HIGH
PRESSURE BUILDS FROM THE N.
A LAND BREEZE WILL ALLOW FOR A LIGHT OFFSHORE WIND THU MORNING. THE
SEABREEZE AND PIEDMONT TROUGH WILL INCREASE SW WINDS TO AROUND 10 KT
THU AFTERNOON AND EVE. SEAS WILL BE 2 FT OR LESS WITH 3 FT SEAS
EXPANDING SOUTHWARD ACROSS THE WATERS FRI NIGHT.
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 300 PM WEDNESDAY...HIGH PRESSURE WILL RIDGE DOWN THE COAST
STRONGLY SAT/SUN BEFORE SLOWLY WEAKENING EARLY NEXT WEEK. AS THIS
HIGH BUILDS SW FROM NEW ENGLAND...IT WILL BE ACCOMPANIED BY A NE
SURGE...DRIVING WINDS UP TO AROUND 15 KT SATURDAY AND SUNDAY.
WINDS WILL VEER SLOWLY ON MONDAY TO BECOME MORE EASTERLY AS THE
RIDGE WEAKENS...WITH SPEEDS DROPPING TO AROUND 10 KT AT THE END OF
THE PERIOD. THE SEA SPECTRUM WILL BE SIGNIFICANTLY DOMINATED BY A
NE WIND WAVE THROUGH THE PERIOD...WHICH WILL MASK A LOW-AMPLITUDE
SE SWELL. WAVE HEIGHTS WILL BE 2-3 FT EARLY SATURDAY...RISING TO
3-4 FT LATE SATURDAY AND SUNDAY AS THE NE FETCH PERSISTS. WAVE
HEIGHTS WILL THEN EASE A BIT MONDAY ON THE SLACKENING WINDS.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...RJD
NEAR TERM...REK/TRA/RGZ
SHORT TERM...RJD
LONG TERM...JDW
AVIATION...DL
MARINE...REK/RJD/TRA/JDW/RGZ/SRP
AREA FORECAST DISCUSSION
NWS BISMARCK ND
948 PM CDT FRI SEP 4 2015
.UPDATE...
ISSUED AT 941 PM CDT FRI SEP 4 2015
NEXT IMPULSE IN SOUTHWEST FLOW IS PRODUCING SHOWERS AND
THUNDERSTORMS FROM FAR SOUTHEAST MONTANA INTO NORTHEAST WYOMING.
THIS ACTIVITY IS TRACKING NORTHEAST AROUND 30-35 MPH AND SHOULD
BEGIN TO MOVE INTO SOUTHWEST NORTH DAKOTA IN THE NEXT FEW HOURS.
LATEST MESOSCALE MODELS SHOW THIS AREA LIFTING THROUGH WESTERN AND
INTO NORTH CENTRAL NORTH DAKOTA THROUGH THE OVERNIGHT HOURS.
UPDATED POP/WX GRIDS BASED ON A BLEND OF THE TIME-LAGGED HRRR AND
PERSISTENCE THROUGH 14 UTC. ALSO EXPANDED OVERCAST CLOUD COVER
ACROSS MAINLY THE NORTH HALF OF THE FORECAST AREA THIS EVENING AND
EXPANDED IT FARTHER SOUTH THROUGH THE OVERNIGHT HOURS.
UPDATE ISSUED AT 637 PM CDT FRI SEP 4 2015
EVEN IN THE SUBSIDENCE BEHIND THE EXITING SHORTWAVE THERE IS STILL
ENOUGH LOW LEVEL INSTABILITY FOR A FEW SHOWERS OR THUNDERSTORMS
OVER CENTRAL NORTH DAKOTA EARLY THIS EVENING. AN ISOLATED
THUNDERSTORM DEVELOPED OVER SHERIDAN COUNTY RECENTLY AS TWO
OUTFLOW BOUNDARIES COLLIDED. WILL KEEP A SLIGHT CHANCE FOR ANOTHER
COUPLE HOURS FROM JUST NORTHEAST OF BISMARCK UP INTO THE TURTLE
MOUNTAINS. LATEST MESOSCALE MODELS ARE SHOWING SHOWERS MOVING INTO
WESTERN NORTH DAKOTA LATER THAN PREVIOUSLY FORECAST. CURRENT
INDICATIONS SUGGEST MORE LIKE AROUND MIDNIGHT OR THEREAFTER. THUS
CUT BACK ON POPS IN THE FAR WEST THIS EVENING. CURRENT RADAR
ANALYSIS INDICATES SHOWER ACTIVITY IS CURRENTLY AROUND GLASGOW AND
FARTHER WEST.
UPDATE ISSUED AT 520 PM CDT FRI SEP 4 2015
QUICK UPDATE FOR POPS/SKY COVER AND TO FRESHEN LATEST SENSIBLE
WEATHER ELEMENTS. SHOWERS HAVE ALL BUT EXITED THE FAR EASTERN
CWA. WILL KEEP A SLIGHT CHANCE OVER FAR EASTERN STUTSMAN INTO
LAMOURE/DICKEY COUNTIES. OTHERWISE EXPECT DRY CONDITIONS INTO THIS
EVENING. CHANCES RETURN OUT WEST AGAIN LATE THIS EVENING.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 225 PM CDT FRI SEP 4 2015
SHOWER AND THUNDERSTORM POTENTIAL TONIGHT THROUGH SATURDAY
HIGHLIGHTS THE SHORT TERM FORECAST.
A BREAK IN PRECIPITATION IS EXPECTED ACROSS NEARLY ALL OF WESTERN
AND CENTRAL NORTH DAKOTA THIS AFTERNOON INTO THE EARLY EVENING
WITH SUBSIDENCE IN THE WAKE OF THE SHORTWAVE PROPAGATING INTO THE
NORTHEASTERN PORTIONS OF THE STATE. THE NEXT WAVE EVIDENT ON WATER
VAPOR IMAGERY ACROSS CENTRAL WYOMING THIS AFTERNOON WILL CONTINUE
TO PROPAGATE NORTHEAST THROUGH THE EVENING AND IMPACT WESTERN
NORTH DAKOTA LATE THIS EVENING AND THROUGH THE OVERNIGHT. AS A
RESULT... SCATTERED SHOWERS AND THUNDERSTORMS RETURN TO THE
FORECAST GENERALLY WEST OF HIGHWAY 83 WITH THIS FEATURE. SEVERE
WEATHER IS NOT EXPECTED. DURING THE DAY ON SATURDAY...RAINFALL IS
EXPECTED TO CONTINUE ACROSS THE NORTHWEST THROUGHOUT THE DAY WITH
MULTIPLE IMPULSES EMBEDDED IN SOUTHWEST FLOW ALOFT. WHILE
NORTHWEST NORTH DAKOTA IS IN THE DAY TWO EXCESSIVE RAINFALL
OUTLOOK...THIS HAS BEEN THE DRIEST PORTION OF THE STATE THIS
SUMMER AND DO NOT ANTICIPATE ANY FLOOD CONCERNS.
ELSEWHERE...EXPECT MORE SCATTERED...DIURNALLY DRIVEN CONVECTIVE
ACTIVITY THROUGH THE AFTERNOON AND EVENING. GIVEN GOOD
AGREEMENT...UTILIZED A BLEND OF THE 12 UTC DETERMINISTIC AND
ENSEMBLE SUITES.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 225 PM CDT FRI SEP 4 2015
COOLER TEMPERATURES HIGHLIGHT THE EXTENDED FORECAST.
THE 12 UTC DETERMINISTIC AND ENSEMBLE SUITES ARE IN GOOD AGREEMENT
ON THE LOW OVER NORTH CENTRAL MONTANA SATURDAY NIGHT PROPAGATING
INTO SASKATCHEWAN THROUGH THE DAY ON SUNDAY. THIS WOULD MARK THE
END OF PRECIPITATION FROM THE SHORT TERM BY SUNDAY MORNING AS
DRIER AIR OVERTAKES THE AREA. THEREAFTER...A MEAN...LOW AMPLITUDE
UPPER LEVEL TROUGH ACROSS THE CENTRAL CONUS FAVORS BELOW NORMAL
TEMPERATURES IN THE 60S AND 70S NEXT WEEK. GIVEN THESE COOLER
TEMPERATES...WILL HAVE TO MONITOR FROST POTENTIAL FOR NEXT WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 941 PM CDT FRI SEP 4 2015
MVFR STRATUS STILL HANGING ON AROUND KMOT AND HAS EXPANDED BACK
INTO KISN. FOG AND STRATUS IS EXPECTED TO BUILD ACROSS MUCH OF
THE AREA AGAIN LATE TONIGHT. SCATTERED SHOWERS AND THUNDERSTORMS
ARE ALSO EXPECTED ACROSS WESTERN NORTH DAKOTA LATE TONIGHT INTO
SATURDAY MORNING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...AYD
LONG TERM...AYD
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
939 AM CDT THU SEP 3 2015
.UPDATE...
ISSUED AT 939 AM CDT THU SEP 3 2015
LOW CLOUDS WEST OF THE RED RIVER ARE BEING STUBBORN AND HANGING
AROUND A BIT LONGER THIS MORNING...ALTHOUGH MOST OF THE FOG HAS
DISSIPATED. THINK THAT THE CLOUDS WILL LINGER FOR A FEW MORE HOURS
BEFORE DISSIPATING COMPLETELY THIS AFTERNOON. STILL THINK THAT THE
NORTH DAKOTA SIDE WILL GET INTO THE LOW 90S...BUT WILL MONITOR IN
CASE THE CLOUDS HANG AROUND A BIT LONGER AND KEEP US A FEW DEGREES
COOLER THAN EXPECTED.
UPDATE ISSUED AT 630 AM CDT THU SEP 3 2015
NO CHANGES NEEDED THIS MORNING. PLENTY OF LOW CLOUDS AND PATCHY
FOG WILL CONTINUE THROUGH ABOUT 14Z OR 15Z BEFORE BURNING OFF.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 330 AM CDT THU SEP 3 2015
THE MAIN CHALLENGE WILL BE CONVECTIVE CHANCES AND TEMPS. MODELS
CONTINUE IN GOOD AGREEMENT OVERALL...WITH THE ECMWF AND NAM VERY
SIMILAR AND PREFERRED.
FOR TODAY...IT WILL BE HOT WITH HEAT INDICES AROUND 100 THIS
AFTERNOON. THERE WILL BE MORNING FOG AND LOW CLOUDS THAT WE WILL
MENTION THROUGH 14Z OR SO.
ON FRIDAY...CONVECTIVE CHANCES WILL INCREASE FROM WEST TO EAST
THROUGH THE DAY. EXPECT A SHORTWAVE TO MOVE INTO THE REGION BY
FRIDAY AFTERNOON/EVENING. THERE WILL BE AMPLE MOISTURE WITH PWATS
AROUND 2 INCHES FRIDAY EVENING...AND MLCAPE AROUND 2000 J/KG. THE
STRONGER DEEP LAYERED SHEAR REMAINS TO THE WEST...BUT GIVEN FAIRLY
STRONG INSTABILITY/MOISTURE...SOME SEVERE STORMS POSSIBLE FRIDAY
AFTERNOON AND OVERNIGHT NEAR THE SFC BOUNDARY.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 330 AM CDT THU SEP 3 2015
FOR FRIDAY NIGHT THROUGH SAT NIGHT...SHOWERS AND STORMS MAY
BECOME LIKELY AS LLJ INCREASES DURING THE EVENING. A SFC BOUNDARY
WILL REMAIN NEARLY STATIONARY AND WILL LIKELY FOCUS SEVERAL ROUNDS
OF STORMS THROUGH SATURDAY NIGHT. GIVEN THE INSTABILITY AND
MOISTURE PROFILE...EVEN WITH WEAKER SHEAR A FEW SEVERE STORMS WILL
BE POSSIBLE. HEAVY RAIN COULD ALSO BECOME A THREAT NEAR AREA THAT
GET REPEATED THUNDERSTORMS GIVEN VERY HIGH PWATS NEAR 2 INCHES.
SUNDAY-WEDNESDAY...THE UPPER LOW FINALLY WILL EJECT INTO THE HIGH
PLAINS ON SUNDAY WITH A COLD FRONT PUSHING THROUGH THE REGION.
DEPENDING ON THE TIMING OF THE FRONTAL PASSAGE AND DEGREE OF
DESTABILIZATION AHEAD OF THE FRONT...SOME STRONG STORMS ARE POSSIBLE
SOMEWHERE OVER THE REGION AS THE WARM MOIST AIR MASS REMAINS IN
PLACE PRECEDING THE BOUNDARY AND DEEP LAYER WIND FIELDS STRENGTHEN.
MONDAY WILL BE MAINLY DRY...BREEZY AND COOLER AS THE SFC LOW LIFTS
INTO SOUTHERN CANADA. TEMPS WILL REMAIN ON THE COOL SIDE THROUGH MID
WEEK WITH MANY AREAS REMAINING IN THE 60S FOR HIGHS. CURRENTLY HAVE
A MAINLY DRY FORECAST TUE-WED...ALTHOUGH MODEL VARIABILITY BECOMES
MUCH GREATER DURING THIS TIME...LEADING TO LOW FORECAST
CONFIDENCE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 630 AM CDT THU SEP 3 2015
IFR/LIFR CIGS AND VSBYS CONTINUE WITH LOW CLOUDS AND PATCHY FOG.
THE HRRR SLOWLY ERODES THESE CLOUDS AND FOG AROUND 15Z...AND HAVE
GONE VFR THEREAFTER. SOME AREAS COULD HOLD ON A BIT LONGER...WITH
SOUTHERLY WINDS GUSTING OVER 20KT POSSIBLE THIS AFTERNOON.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...DK
LONG TERM...DK/MAKOWSKI
AVIATION...DK
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
630 AM CDT THU SEP 3 2015
.UPDATE...
ISSUED AT 630 AM CDT THU SEP 3 2015
NO CHANGES NEEDED THIS MORNING. PLENTY OF LOW CLOUDS AND PATCHY
FOG WILL CONTINUE THROUGH ABOUT 14Z OR 15Z BEFORE BURNING OFF.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 330 AM CDT THU SEP 3 2015
THE MAIN CHALLENGE WILL BE CONVECTIVE CHANCES AND TEMPS. MODELS
CONTINUE IN GOOD AGREEMENT OVERALL...WITH THE ECMWF AND NAM VERY
SIMILAR AND PREFERRED.
FOR TODAY...IT WILL BE HOT WITH HEAT INDICES AROUND 100 THIS
AFTERNOON. THERE WILL BE MORNING FOG AND LOW CLOUDS THAT WE WILL
MENTION THROUGH 14Z OR SO.
ON FRIDAY...CONVECTIVE CHANCES WILL INCREASE FROM WEST TO EAST
THROUGH THE DAY. EXPECT A SHORTWAVE TO MOVE INTO THE REGION BY
FRIDAY AFTERNOON/EVENING. THERE WILL BE AMPLE MOISTURE WITH PWATS
AROUND 2 INCHES FRIDAY EVENING...AND MLCAPE AROUND 2000 J/KG. THE
STRONGER DEEP LAYERED SHEAR REMAINS TO THE WEST...BUT GIVEN FAIRLY
STRONG INSTABILITY/MOISTURE...SOME SEVERE STORMS POSSIBLE FRIDAY
AFTERNOON AND OVERNIGHT NEAR THE SFC BOUNDARY.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 330 AM CDT THU SEP 3 2015
FOR FRIDAY NIGHT THROUGH SAT NIGHT...SHOWERS AND STORMS MAY
BECOME LIKELY AS LLJ INCREASES DURING THE EVENING. A SFC BOUNDARY
WILL REMAIN NEARLY STATIONARY AND WILL LIKELY FOCUS SEVERAL ROUNDS
OF STORMS THROUGH SATURDAY NIGHT. GIVEN THE INSTABILITY AND
MOISTURE PROFILE...EVEN WITH WEAKER SHEAR A FEW SEVERE STORMS WILL
BE POSSIBLE. HEAVY RAIN COULD ALSO BECOME A THREAT NEAR AREA THAT
GET REPEATED THUNDERSTORMS GIVEN VERY HIGH PWATS NEAR 2 INCHES.
SUNDAY-WEDNESDAY...THE UPPER LOW FINALLY WILL EJECT INTO THE HIGH
PLAINS ON SUNDAY WITH A COLD FRONT PUSHING THROUGH THE REGION.
DEPENDING ON THE TIMING OF THE FRONTAL PASSAGE AND DEGREE OF
DESTABILIZATION AHEAD OF THE FRONT...SOME STRONG STORMS ARE POSSIBLE
SOMEWHERE OVER THE REGION AS THE WARM MOIST AIR MASS REMAINS IN
PLACE PRECEDING THE BOUNDARY AND DEEP LAYER WIND FIELDS STRENGTHEN.
MONDAY WILL BE MAINLY DRY...BREEZY AND COOLER AS THE SFC LOW LIFTS
INTO SOUTHERN CANADA. TEMPS WILL REMAIN ON THE COOL SIDE THROUGH MID
WEEK WITH MANY AREAS REMAINING IN THE 60S FOR HIGHS. CURRENTLY HAVE
A MAINLY DRY FORECAST TUE-WED...ALTHOUGH MODEL VARIABILITY BECOMES
MUCH GREATER DURING THIS TIME...LEADING TO LOW FORECAST
CONFIDENCE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 630 AM CDT THU SEP 3 2015
IFR/LIFR CIGS AND VSBYS CONTINUE WITH LOW CLOUDS AND PATCHY FOG.
THE HRRR SLOWLY ERODES THESE CLOUDS AND FOG AROUND 15Z...AND HAVE
GONE VFR THEREAFTER. SOME AREAS COULD HOLD ON A BIT LONGER...WITH
SOUTHERLY WINDS GUSTING OVER 20KT POSSIBLE THIS AFTERNOON.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...DK
SHORT TERM...DK
LONG TERM...DK/MAKOWSKI
AVIATION...DK
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1242 AM CDT THU SEP 3 2015
.UPDATE...
ISSUED AT 1242 AM CDT THU SEP 3 2015
MAIN CONCERN THIS UPDATE IS FOG POSSIBILITY...ESPECIALLY ACROSS
CENTRAL NORTH DAKOTA. DEWPOINT TEMPERATURES IN THE 60S TO LOWER 70S
WITH HUMID SOUTHEAST FLOW. RELATIVE HUMIDITY VALUES ALREADY REACHING
100 PERCENT SOME LOCALES. WENT WITH PATCHY FOG CENTRAL. ONLY
LIMITING FACTOR FOR MORE WIDESPREAD FOG WOULD BE THE SOUTHEAST WINDS
OF 5 TO 10 MPH THAT MAY BE ENOUGH TO KEEP SUFFICIENT MIXING TO LIMIT
WIDESPREAD NATURE OF FOG. OTHERWISE ADJUSTED CURRENT HOURLY
TEMPERATURE TRENDS. CURRENT FORECAST ON TRACK.
UPDATE ISSUED AT 943 PM CDT WED SEP 2 2015
NO CHANGES TO THE GOING FORECAST.
UPDATE ISSUED AT 754 PM CDT WED SEP 2 2015
MONTANA SHOWERS DISSIPATED AS THEY NEARED THE NORTH DAKOTA BORDER.
UPDATED TO DRY OUT THE FORECAST.
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 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1242 AM CDT THU SEP 3 2015
LOW PRESSURE IN EASTERN MONTANA IS FORECAST TO MOVE EASTWARD TO THE
ND/MT BORDER BY DAYBREAK...AND INTO CENTRAL NORTH DAKOTA BY AROUND
00Z. SOUTHEAST WINDS EARLY THIS MORNING WILL CONTINUE TO BRING HUMID
AIR INTO THE REGION...WITH PATCHY FOG POSSIBLE TOWARD DAYBREAK.
ADDED TEMPO 3SM BR BETWEEN 10Z-14Z FOR NOW AT KMOT/KBIS/KJMS.
OTHERWISE VFR CONDITIONS AFTER 14Z EXPECTED. ISOLATED THUNDERSTORMS
POSSIBLE THIS AFTERNOON NORTHWESTERN ND BUT CHANCES TOO SMALL TO
MENTION IN TAFS. SCATTERED TSTMS POSSIBLE AFT 00Z AT
KISN/KDIK/KMOT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JV
SHORT TERM...WAA
LONG TERM...NH
AVIATION...JV
AREA FORECAST DISCUSSION
NWS MEDFORD OR
853 PM PDT FRI SEP 4 2015
.UPDATE...COLD AIR MOVING IN PLACE THIS TONIGHT IS BRINGING
LOWERED SNOW LEVELS. SNOW LEVELS HAVE ALREADY DROPPED TO AROUND
6500 FEET BASED ON OBSERVATIONS NEAR CRATER LAKE. SNOW LEVELS ARE
EXPECTED TO LOWER DOWN TO AROUND 6000 TO 6500 FEET OVER MOST THE
AREA WITH SNOW LEVELS LOCALLY DOWN TO 5500 FT IN THE SOUTHERN
OREGON CASCADES. THIS MAY BRING A LIGHT DUSTING OF SNOW IN
CONTINUED LIGHT SHOWERS TONIGHT OVER THE HIGHER CASCADES AND FOR
HIGHER MOUNTAINS EAST OF THE CASCADES.
&&
.PREV DISCUSSION... /ISSUED 832 PM PDT FRI SEP 4 2015/
SHORT TERM...SHOWERS HAVE BEGUN TO DECREASE ON WEST SIDE WITH
MOST THE ACTIVITY FROM THE CASCADES EAST AND ISOLATED
THUNDERSTORMS HAVE ALSO DECREASED AND BECOME LIMITED TO EAST SIDE
AREAS. MODELS CONTINUE TO SHOW THAT SHOWER WILL SHIFT EAST IN
RESPONSE TO THE UPPER LOW GRADUALLY MOVING INTO EASTERN OREGON
TONIGHT, THEN BECOMING CENTERED NORTHEAST OF THE CWA ON SATURDAY.
SOME LINGERING SHOWERS AND CLOUDS ARE EXPECTED ON THE BACKSIDE OF
THE TROUGH MAINLY ALONG THE CASCADES AND SISKIYOUS TONIGHT AND
OVER PORTIONS OF THE EAST SIDE, MAINLY LAKE AND MODOC COUNTIES,
TONIGHT INTO EARLY SATURDAY MORNING.
MODELS CONTINUE TO SHOW DECREASING CLOUD COVER BY EARLY MORNING
SATURDAY AND HAVE TRENDED QUICKER WITH THE SHOWER ACTIVITY MOVING
EAST OF THE AREA BY EARLY SATURDAY AFTERNOON. THE CLEARING SKIES
COMBINED WITH COLD AIR ADVECTION AND WINDS BECOMING LIGHT IS
EXPECTED TO BRING A FROST RISK FOR EASTERN VALLEYS SATURDAY
MORNING. THEN TEMPERATURES WILL WARM DURING THE DAY INTO THE 70S
FOR WEST SIDE VALLEYS AND INTO THE 60S FOR EAST SIDE VALLEYS.
THESE TEMPERATURES WILL BE MUCH COOLER THAN NORMAL FOR THIS TIME
OF YEAR DUE TO THE LINGERING COLD AIRMASS OVER THE AREA.
LATE SATURDAY INTO SUNDAY, EXPECT DRY WEATHER TO REMAIN OVER
THE AREA WITH A BROAD UPPER TROUGH TO THE NORTH AND A HIGH
PRESSURE RIDGE OFFSHORE. EXPECT A COOL START TO THE DAY WITH SOME
COLD AIR REMAINING IN PLACE, ESPECIALLY EAST OF THE CASCADES WHERE
FREEZING TEMPERATURES ARE LIKELY. THEN DAYTIME TEMPERATURES WILL
WARM UP ON SUNDAY WITH HIGHS IN THE 70S EAST OF THE CASCADES AND
HIGH IN THE LOWER 80S TO UPPER 70S FOR WEST SIDE VALLEYS.
AVIATION...FOR THE 05/00Z TAF CYCLE... SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS EAST OF THE COASTAL RANGE WILL CONTINUE
THROUGH THIS EVENING. THESE WILL CAUSE PARTIAL TERRAIN
OBSCURATIONS AND ISOLATED MVFR CONDITIONS. OVERNIGHT...AREAS OF
MVFR AND LOCAL IFR IS EXPECTED IN LOW CLOUDS ON THE NORTH AND
NORTHWEST SLOPES IN SOUTHWEST OREGON. OTHERWISE, CONDITIONS WILL
BE VFR THROUGH SATURDAY EVENING. /DW
MARINE...UPDATED 530 PM PDT FRIDAY 4 SEPTEMBER 2015...MODERATE TO
STRONG NORTH WINDS WILL LIKELY CONTINUE THROUGH NEXT WEEK WITH THE
STRONGEST WINDS DURING THE AFTERNOON AND EVENING HOURS AND SOUTH
OF CAPE BLANCO BEYOND 10 NAUTICAL MILES FROM SHORE. WINDS ARE
LIKELY TO BE STRONGEST ON MONDAY WITH GALES POSSIBLE OVER THE
OUTER PORTION OF THE SOUTHERN WATERS ON MONDAY AND TUESDAY. /DW
PREV DISCUSSION (EDITED)... /ISSUED 556 PM PDT FRI SEP 4 2015/
UPDATE...AN UPPER LOW IS BRINGING SHOWERS WITH ISOLATED
THUNDERSTORMS TO THE AREA THIS EVENING. HAVE UPDATED THE FORECAST
TO INCLUDE ISOLATED THUNDERSTORMS IN THE UMPQUA AREA THIS
EVENING SINCE ISOLATED THUNDERSTORMS ARE STILL OCCURRING OVER
THIS AREA. MODELS INDICATE THAT SHOWER ACTIVITY WILL GRADUALLY
PUSH EASTWARD AS THE UPPER LOW MOVES TO THE EAST TONIGHT.
DURING THE MORNING SATURDAY, EXPECT THE LOW TO BECOME CENTERED
NORTHEAST OF THE AREA. SOME CONTINUED MOISTURE IN NORTHWEST FLOW
AROUND THE BACKSIDE OF UPPER TROUGH, WILL KEEP SOME LINGERING
CLOUDS AND SHOWERS IN PLACE, MAINLY ALONG THE CASCADES AND
SISKIYOUS AND INTO EASTERN AREAS, MAINLY IN EASTERN LAKE COUNTY.
COLD AIR ADVECTION IS EXPECTED TO LOWER THE MORNING TEMPERATURES
IN EAST SIDE AREAS INTO THE MID 30S. THIS COLD AIR COMBINED WITH SOME
PARTIAL CLEARING OF THE SKIES DURING THE EARLY MORNING MAY ALLOW
FOR TEMPERATURES TO LOWER FURTHER DOWN INTO THE LOWER 30S. THE LOW
TEMPERATURES COMBINED PARTIALLY CLEAR SKIES AND LIGHT WINDS MAY BRING
ANOTHER NIGHT WITH FROST POTENTIAL IN EAST SIDE VALLEYS. WHILE
THERE REMAINS SOME UNCERTAINTY ON HOW COLD CONDITIONS WILL GET
EARLY SATURDAY MORNING, MAINLY DUE TO CLOUD COVER, HAVE OPTED
TO ADD AREAS OF FROST ESPECIALLY GIVEN THAT THE LATEST HRRR HIGH
RESOLUTION MODEL RUN WHICH SUPPORTS CLEARING BETWEEN 10Z-15Z. HAVE
ISSUED A FROST ADVISORY FOR EASTERN VALLEYS.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...FROST ADVISORY FROM 3 AM TO 8 AM PDT SATURDAY FOR ORZ029>031.
FREEZE WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY MORNING FOR
ORZ029>031.
CA...FROST ADVISORY FROM 3 AM TO 8 AM PDT SATURDAY FOR CAZ084-085.
FREEZE WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY MORNING FOR
CAZ084-085.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR PZZ376.
SMALL CRAFT ADVISORY FROM 2 PM SATURDAY TO 11 PM PDT SUNDAY FOR
PZZ376.
SMALL CRAFT ADVISORY FROM 2 PM TO 11 PM PDT SATURDAY FOR PZZ356.
$$
CC/CC/CC
AREA FORECAST DISCUSSION
NWS MEDFORD OR
832 PM PDT FRI SEP 4 2015
.SHORT TERM...SHOWERS HAVE BEGUN TO DECREASE ON WEST SIDE WITH
MOST THE ACTIVITY FROM THE CASCADES EAST AND ISOLATED
THUNDERSTORMS HAVE ALSO DECREASED AND BECOME LIMITED TO EAST SIDE
AREAS. MODELS CONTINUE TO SHOW THAT SHOWER WILL SHIFT EAST IN
RESPONSE TO THE UPPER LOW GRADUALLY MOVING INTO EASTERN OREGON
TONIGHT, THEN BECOMING CENTERED NORTHEAST OF THE CWA ON SATURDAY.
SOME LINGERING SHOWERS AND CLOUDS ARE EXPECTED ON THE BACKSIDE OF
THE TROUGH MAINLY ALONG THE CASCADES AND SISKIYOUS TONIGHT AND
OVER PORTIONS OF THE EAST SIDE, MAINLY LAKE AND MODOC COUNTIES,
TONIGHT INTO EARLY SATURDAY MORNING.
MODELS CONTINUE TO SHOW DECREASING CLOUD COVER BY EARLY MORNING
SATURDAY AND HAVE TRENDED QUICKER WITH THE SHOWER ACTIVITY MOVING
EAST OF THE AREA BY EARLY SATURDAY AFTERNOON. THE CLEARING SKIES
COMBINED WITH COLD AIR ADVECTION AND WINDS BECOMING LIGHT IS
EXPECTED TO BRING A FROST RISK FOR EASTERN VALLEYS SATURDAY
MORNING. THEN TEMPERATURES WILL WARM DURING THE DAY INTO THE 70S
FOR WEST SIDE VALLEYS AND INTO THE 60S FOR EAST SIDE VALLEYS.
THESE TEMPERATURES WILL BE MUCH COOLER THAN NORMAL FOR THIS TIME
OF YEAR DUE TO THE LINGERING COLD AIRMASS OVER THE AREA.
LATE SATURDAY INTO SUNDAY, EXPECT DRY WEATHER TO REMAIN OVER
THE AREA WITH A BROAD UPPER TROUGH TO THE NORTH AND A HIGH
PRESSURE RIDGE OFFSHORE. EXPECT A COOL START TO THE DAY WITH SOME
COLD AIR REMAINING IN PLACE, ESPECIALLY EAST OF THE CASCADES WHERE
FREEZING TEMPERATURES ARE LIKELY. THEN DAYTIME TEMPERATURES WILL
WARM UP ON SUNDAY WITH HIGHS IN THE 70S EAST OF THE CASCADES AND
HIGH IN THE LOWER 80S TO UPPER 70S FOR WEST SIDE VALLEYS.
&&
.AVIATION...FOR THE 05/00Z TAF CYCLE... SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS EAST OF THE COASTAL RANGE WILL CONTINUE
THROUGH THIS EVENING. THESE WILL CAUSE PARTIAL TERRAIN
OBSCURATIONS AND ISOLATED MVFR CONDITIONS. OVERNIGHT...AREAS OF
MVFR AND LOCAL IFR IS EXPECTED IN LOW CLOUDS ON THE NORTH AND
NORTHWEST SLOPES IN SOUTHWEST OREGON. OTHERWISE, CONDITIONS WILL
BE VFR THROUGH SATURDAY EVENING. /DW
&&
.MARINE...UPDATED 530 PM PDT FRIDAY 4 SEPTEMBER 2015...MODERATE TO
STRONG NORTH WINDS WILL LIKELY CONTINUE THROUGH NEXT WEEK WITH
THE STRONGEST WINDS DURING THE AFTERNOON AND EVENING HOURS AND
SOUTH OF CAPE BLANCO BEYOND 10 NAUTICAL MILES FROM SHORE. WINDS
ARE LIKELY TO BE STRONGEST ON MONDAY WITH GALES POSSIBLE OVER THE
OUTER PORTION OF THE SOUTHERN WATERS ON MONDAY AND TUESDAY. /DW
&&
.PREV DISCUSSION (EDITED)... /ISSUED 556 PM PDT FRI SEP 4 2015/
UPDATE...AN UPPER LOW IS BRINGING SHOWERS WITH ISOLATED
THUNDERSTORMS TO THE AREA THIS EVENING. HAVE UPDATED THE FORECAST
TO INCLUDE ISOLATED THUNDERSTORMS IN THE UMPQUA AREA THIS
EVENING SINCE ISOLATED THUNDERSTORMS ARE STILL OCCURRING OVER
THIS AREA. MODELS INDICATE THAT SHOWER ACTIVITY WILL GRADUALLY
PUSH EASTWARD AS THE UPPER LOW MOVES TO THE EAST TONIGHT.
DURING THE MORNING SATURDAY, EXPECT THE LOW TO BECOME CENTERED
NORTHEAST OF THE AREA. SOME CONTINUED MOISTURE IN NORTHWEST FLOW
AROUND THE BACKSIDE OF UPPER TROUGH, WILL KEEP SOME LINGERING
CLOUDS AND SHOWERS IN PLACE, MAINLY ALONG THE CASCADES AND
SISKIYOUS AND INTO EASTERN AREAS, MAINLY IN EASTERN LAKE COUNTY.
COLD AIR ADVECTION IS EXPECTED TO LOWER THE MORNING TEMPERATURES
IN EAST SIDE AREAS INTO THE MID 30S. THIS COLD AIR COMBINED WITH SOME
PARTIAL CLEARING OF THE SKIES DURING THE EARLY MORNING MAY ALLOW
FOR TEMPERATURES TO LOWER FURTHER DOWN INTO THE LOWER 30S. THE LOW
TEMPERATURES COMBINED PARTIALLY CLEAR SKIES AND LIGHT WINDS MAY BRING
ANOTHER NIGHT WITH FROST POTENTIAL IN EAST SIDE VALLEYS. WHILE
THERE REMAINS SOME UNCERTAINTY ON HOW COLD CONDITIONS WILL GET
EARLY SATURDAY MORNING, MAINLY DUE TO CLOUD COVER, HAVE OPTED
TO ADD AREAS OF FROST ESPECIALLY GIVEN THAT THE LATEST HRRR HIGH
RESOLUTION MODEL RUN WHICH SUPPORTS CLEARING BETWEEN 10Z-15Z. HAVE
ISSUED A FROST ADVISORY FOR EASTERN VALLEYS.
PREV LONG RANGE DISCUSSION... /ISSUED 1258 PM PDT FRI SEP 4 2015/
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
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...FROST ADVISORY FROM 3 AM TO 8 AM PDT SATURDAY FOR ORZ029>031.
FREEZE WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY MORNING FOR
ORZ029>031.
CA...FROST ADVISORY FROM 3 AM TO 8 AM PDT SATURDAY FOR CAZ084-085.
FREEZE WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY MORNING FOR
CAZ084-085.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR PZZ376.
SMALL CRAFT ADVISORY FROM 2 PM SATURDAY TO 11 PM PDT SUNDAY FOR
PZZ376.
SMALL CRAFT ADVISORY FROM 2 PM TO 11 PM PDT SATURDAY FOR PZZ356.
$$
CC
AREA FORECAST DISCUSSION
NWS MEDFORD OR
556 PM PDT FRI SEP 4 2015
.UPDATE...AN UPPER LOW IS BRINGING SHOWERS WITH ISOLATED
THUNDERSTORMS TO THE AREA THIS EVENING. HAVE UPDATED THE FORECAST
TO INCLUDE ISOLATED THUNDERSTORMS IN THE UMPQUA AREA THIS
EVENING SINCE ISOLATED THUNDERSTORMS ARE STILL OCCURRING OVER
THIS AREA. MODELS INDICATE THAT SHOWER ACTIVITY WILL GRADUALLY
PUSH EASTWARD AS THE UPPER LOW MOVES TO THE EAST TONIGHT.
DURING THE MORNING SATURDAY, EXPECT THE LOW TO BECOME CENTERED
NORTHEAST OF THE AREA. SOME CONTINUED MOISTURE IN NORTHWEST FLOW
AROUND THE BACKSIDE OF UPPER TROUGH, WILL KEEP SOME LINGERING
CLOUDS AND SHOWERS IN PLACE, MAINLY ALONG THE CASCADES AND
SISKIYOUS AND INTO EASTERN AREAS, MAINLY IN EASTERN LAKE COUNTY.
COLD AIR ADVECTION IS EXPECTED TO LOWER THE MORNING TEMPERATURES
IN EAST SIDE AREAS INTO THE MID 30S. THIS COLD AIR COMBINED WITH SOME
PARTIAL CLEARING OF THE SKIES DURING THE EARLY MORNING MAY ALLOW
FOR TEMPERATURES TO LOWER FURTHER DOWN INTO THE LOWER 30S. THE LOW
TEMPERATURES COMBINED PARTIALLY CLEAR SKIES AND LIGHT WINDS MAY BRING
ANOTHER NIGHT WITH FROST POTENTIAL IN EAST SIDE VALLEYS. WHILE
THERE REMAINS SOME UNCERTAINTY ON HOW COLD CONDITIONS WILL GET
EARLY SATURDAY MORNING, MAINLY DUE TO CLOUD COVER, HAVE OPTED
TO ADD AREAS OF FROST ESPECIALLY GIVEN THAT THE LATEST HRRR HIGH
RESOLUTION MODEL RUN WHICH SUPPORTS CLEARING BETWEEN 10Z-15Z. HAVE
ISSUED A FROST ADVISORY FOR EASTERN VALLEYS.
LATE SATURDAY INTO SUNDAY, EXPECT DRY WEATHER OVER THE AREA WITH
A BROAD UPPER TROUGH TO THE NORTH AND A HIGH PRESSURE RIDGE
OFFSHORE. EXPECT A COOL START TO THE DAY WITH SOME COLD AIR
REMAINING IN PLACE, ESPECIALLY EAST OF THE CASCADES WHERE FREEZING
TEMPERATURES ARE LIKELY. THEN DAYTIME TEMPERATURES WILL WARM UP ON
SUNDAY WITH HIGHS IN THE 70S EAST OF THE CASCADES AND HIGH IN THE
LOWER 80S TO UPPER 70S FOR WEST SIDE VALLEYS.
&&
.AVIATION...FOR THE 05/00Z TAF CYCLE... NUMEROUS SHOWERS AND
ISOLATED THUNDERSTORMS EAST OF THE COASTAL RANGE WILL CONTINUE
THROUGH THIS EVENING. THESE WILL CAUSE PARTIAL TERRAIN OBSCURATIONS
AND ISOLATED MVFR CONDITIONS. OVERNIGHT...AREAS OF MVFR AND LOCAL
IFR CIGS ARE EXPECTED IN LOW CLOUDS ON THE NORTH AND NORTHWEST
SLOPES IN SOUTHWEST OREGON. OTHERWISE, CONDITIONS WILL BE VFR
THROUGH SATURDAY EVENING. /DW
&&
.MARINE...UPDATED 530 PM PDT FRIDAY 4 SEPTEMBER 2015...MODERATE
NORTH WINDS WILL LIKELY CONTINUE THROUGH NEXT WEEK WITH THE
STRONGEST WINDS DURING THE AFTERNOON AND EVENING HOURS AND SOUTH OF
CAPE BLANCO BEYOND 10 NAUTICAL MILES FROM SHORE. WINDS ARE LIKELY TO
BE STRONGEST ON MONDAY WITH GALES POSSIBLE OVER THE OUTER PORTION OF
THE SOUTHERN WATERS ON MONDAY AND TUESDAY. /DW
&&
.PREV DISCUSSION... /ISSUED 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 THE 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
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...FROST ADVISORY FROM 3 AM TO 8 AM PDT SATURDAY FOR ORZ029>031.
FREEZE WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY MORNING FOR
ORZ029>031.
CA...FROST ADVISORY FROM 3 AM TO 8 AM PDT SATURDAY FOR CAZ084-085.
FREEZE WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY MORNING FOR
CAZ084-085.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR PZZ376.
SMALL CRAFT ADVISORY FROM 2 PM SATURDAY TO 11 PM PDT SUNDAY FOR
PZZ376.
SMALL CRAFT ADVISORY FROM 2 PM TO 11 PM PDT SATURDAY FOR PZZ356.
$$
CC
AREA FORECAST DISCUSSION
NWS MEDFORD OR
1145 AM PDT THU SEP 3 2015
.DISCUSSION...THE LATEST VISIBLE IMAGE SHOWS A BAND OF CLOUDS
MOVING SOUTHWEST TO NORTHEAST IN SOUTHEAST KLAMATH, LAKE EASTERN
SISKIYOU AND MOST OF MODOC COUNTY. A FEW RAWS SITES IN THESE
LOCATIONS PICKED UP LIGHT RAINFALL WITH ANYWHERE BETWEEN 0.01 AND
0.10 OF AN INCH BETWEEN LAST NIGHT AND THIS MORNING. THE RADAR
IMAGE IS NOT SHOWING ANYTHING BECAUSE THE RAIN IS OCCURRING AT
LOWER LEVELS WHICH IS NOT BEING PICKED UP. MEANWHILE A ISOLATED
SHOWERS IN ASSOCIATION WITH A WEAK SHORTWAVE TROUGH WITHIN THE
MUCH LARGER UPPER LOW IS MOVING INLAND JUST NORTH OF OUR FORECAST
AREA. THESE ISOLATED SHOWERS SHOULD REMAIN TO OUR NORTH TODAY.
THE UPPER LOW WILL MOVE SOUTH TONIGHT AND MORE SHORTWAVE ENERGY
WILL ROTATE AROUND THE UPPER LOW WITH THE FIRST IN A SERIES
EXPECTED TO SWING INTO NORTHWEST CAL EARLY FRIDAY MORNING. COLD
AIR ALOFT WITH 500MB TEMPERATURES NEAR -23C WILL OVER THE MARINE
WATERS LATE TONIGHT SO COULD NOT RULE OUT AN ISOLATED THUNDERSTORM
OR TWO.
FRIDAY WILL BE THE MOST ACTIVE DAY IN THE PERIOD AS THE UPPER LOW
AND COLD AIR ALOFT MOVES OVERHEAD WITH SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS. IT`S POSSIBLE WE COULD HAVE MORE
THUNDERSTORM ACTIVITY FRIDAY AFTERNOON EAST OF THE CASCADES. IT`S
ALSO POSSIBLE SOME THUNDERSTORMS COULD PRODUCE GUSTY WINDS AND
SMALL HAIL. -PETRUCELLI
&&
.AVIATION...FOR THE 03/18Z TAF CYCLE... VFR CONDITIONS ARE EXPECTED
TO PREVAIL THROUGH TODAY AT VALLEY LOCATIONS. PARTIAL MOUNTAIN
OBSCURATION SHOULD BE EXPECTED ACROSS MOST MOUNTAIN AREAS TODAY,
PRIMARILY EAST OF MOUNT SHASTA AND KLAMATH FALLS AND FROM THE UMPQUA
DIVIDE NORTHWARD. LATE TONIGHT THROUGH FRIDAY MORNING SCATTERED MVFR
CEILINGS ARE POSSIBLE ON THE COAST NORTH OF CAPE BLANCO AND FROM THE
UMPQUA DIVIDE NORTHWARD. CLOUDS WILL INCREASE AFTER SUNRISE FRIDAY
MORNING, ESPECIALLY EAST OF THE COAST RANGE, WITH DETERIORATING
CIG/VIS CONDITIONS IN SHOWERS AND ISOLATED THUNDERSTORMS FRIDAY
AFTERNOON. BTL
&&
.MARINE...UPDATED 830 AM PDT THURSDAY 3 SEPTEMBER 2015...SMALL CRAFT
ADVISORY LEVEL NORTH WINDS AT THE LOW END OF CRITERIA WILL DEVELOP
SOUTH OF GOLD BEACH BEYOND 5 NM FROM SHORE LATE THIS MORNING. THESE
WINDS WILL REACH A PEAK IN THE EARLY EVENING THEN DIMINISH OVERNIGHT
BEFORE RETURNING TO ABOUT THE SAME STRENGTH FOR LATE FRIDAY MORNING
THROUGH FRIDAY EVENING. AFTER ANOTHER DECREASE IN WINDS LATE FRIDAY
NIGHT, WINDS WILL BECOME STRONGER DURING THE WEEKEND. WINDS WILL
STILL BE MODERATE SATURDAY BUT GALES ARE POSSIBLE IN THE SOUTHERN
OUTER WATERS WITH SMALL CRAFT WINDS ELSEWHERE SUNDAY INTO MONDAY.
WINDS ARE EXPECTED TO RETURN TO MODERATE STRENGTH BEYOND MONDAY.
BTL/DW
&&
.PREV DISCUSSION... /ISSUED 351 AM PDT THU SEP 3 2015/
DISCUSSION...A COLD FRONT THAT MOVED THROUGH LATE WEDNESDAY HAS
LEFT MOST OF THE AREA 5 TO 10 DEGREES COOLER VERSUS THIS TIME VERSUS
YESTERDAY. EVENING SHIFT PUT UP A FROST ADVISORY FOR SOME OF THE
EAST SIDE. THE DAY SHIFT TODAY WILL NEED TO CONSIDER THE SAME FOR
TONIGHT AND FRIDAY NIGHT AS THE CENTER OF AN UNUSUALLY COLD UPPER
LOW DIVES IN OVERHEAD. THIS LOW WILL BRING THE COOLEST AIR OF THE
SEASON WITH A COLD CORE OF -25C AT 500 MILLIBARS. AS THE TROUGH
SWINGS EASTWARD AND SKIES CLEAR SATURDAY NIGHT INTO SUNDAY...
THERE WILL BE A THREAT FOR FREEZING MORNING TEMPERATURES ACROSS
MUCH OF THE LOWLANDS EAST OF THE CASCADES. A SPECIAL WEATHER
STATEMENT WILL COVER THIS UPCOMING POTENTIAL FOR FROST AND FREEZE
FOR AGRICULTURAL INTERESTS.
RAIN WITH THIS SYSTEM TODAY SHOULD REMAIN FAIRLY SLIM. THE 88D IS
CURRENTLY SHOWING SOME WEAK ECHOES STREAMING SOUTHWEST TO
NORTHEAST BETWEEN KLAMATH FALLS AND LAKEVIEW IN REGION OF COLDER
CLOUD TOPS BETWEEN -10 TO -15C IN THICKER CLOUD. PER THE RUC AND
HRRR FORECASTS, WE DID BUMP UP PROBABILITIES A BIT FOR A HUNDREDTH
OR TWO OUR THERE AROUND SOUTHERN LAKE COUNTY WITH SHORT WAVE
ENERGY OVERRIDING THE SLOWLY PROGRESSING FRONTAL ZONE. THIS SHOULD
TAPER OFF THIS EVENING WITH A FAIRLY UNEVENTFUL NIGHT IN STORE.
ACTIVITY WILL INCREASE FRIDAY WITH THE APPROACH OF THE DEEP UPPER
LOW FROM THE NORTH. FAIRLY STRONG SHORT WAVE ENERGY IS FORECAST TO
DIG THROUGH THE BASE OF THE TROUGH OVER SOUTHERN OREGON AND NORTHERN
CALIFORNIA FRIDAY AFTERNOON AND EVENING. WITH THE COLD AIR ALOFT,
NUMEROUS SHOWERS AND A SLIGHT CHANCE FOR THUNDERSTORMS WITH SOME
LOCALIZED MODERATE RAINS ARE IN STORE. THE BEST SHOT AT GOOD RAIN
WILL BE EAST OF THE CASCADES. DUE TO BUILDING CONFIDENCE BASED ON
SUPPORT FROM RECENT MODEL RUNS, HAVE ALSO BUMPED UP POPS A BIT
MORE IN THIS TIME FRAME.
SHOWERS WILL BE LINGERING INTO SATURDAY MORNING MAINLY FROM THE
CASCADES EAST. SNOW LEVELS EARLY SATURDAY SHOULD BOTTOM OUT BETWEEN
6000 AND 6500 FEET OVER THE CASCADES, AND MORE LIKE 7KFT IN
NORTHERN CALIFORNIA. SO, A LITTLE DUSTING ON THE HIGHER TERRAIN
LOOKS LIKELY. SOME UNCERTAINTY EXISTS FOR AREAS IN LAKE COUNTY
WHERE THE MORE SIGNIFICANT PRECIP WILL FALL. THE WARNERS INCLUDING
HART MTN AREA ABOVE 6500 FEET SHOULD BE AWARE OF THE POTENTIAL FOR
A LITTLE MORE SNOW THERE.
AS THE SYSTEM CLEARS OUT SATURDAY AFTERNOON AND NIGHT, THIS WILL
LEAVE SUNDAY MORNING WITH A FAIR POTENTIAL TO FREEZE IN MANY AREAS
OF WHAT LOOKS LIKE MAINLY LAKE AND MODOC COUNTIES. A WARMING TREND
LOOKS LIKELY THEREAFTER THROUGH LATE WEEK. STAVISH
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR
PZZ356-376.
SMALL CRAFT ADVISORY FROM 11 AM TO 11 PM PDT FRIDAY FOR PZZ376.
$$
AREA FORECAST DISCUSSION
NWS MEDFORD OR
859 AM PDT THU SEP 3 2015
.DISCUSSION...THE LATEST VISIBLE IMAGE SHOWS A BAND OF CLOUDS
MOVING SOUTHWEST TO NORTHEAST IN SOUTHEAST KLAMATH, LAKE EASTERN
SISKIYOU AND MOST OF MODOC COUNTY. A FEW RAWS SITES IN THESE
LOCATIONS PICKED UP LIGHT RAINFALL WITH ANYWHERE BETWEEN 0.01 AND
0.10 OF AN INCH BETWEEN LAST NIGHT AND THIS MORNING. THE RADAR
IMAGE IS NOT SHOWING ANYTHING BECAUSE THE RAIN IS OCCURRING AT
LOWER LEVELS WHICH IS NOT BEING PICKED UP. MEANWHILE A ISOLATED
SHOWERS IN ASSOCIATION WITH A WEAK SHORTWAVE TROUGH WITHIN THE
MUCH LARGER UPPER LOW IS MOVING INLAND JUST NORTH OF OUR FORECAST
AREA. THESE ISOLATED SHOWERS SHOULD REMAIN TO OUR NORTH TODAY.
THE UPPER LOW WILL MOVE SOUTH TONIGHT AND MORE SHORTWAVE ENERGY
WILL ROTATE AROUND THE UPPER LOW WITH THE FIRST IN A SERIES
EXPECTED TO SWING INTO NORTHWEST CAL EARLY FRIDAY MORNING. COLD
AIR ALOFT WITH 500MB TEMPERATURES NEAR -23C WILL OVER THE MARINE
WATERS LATE TONIGHT SO COULD NOT RULE OUT AN ISOLATED THUNDERSTORM
OR TWO.
FRIDAY WILL BE THE MOST ACTIVE DAY IN THE PERIOD AS THE UPPER LOW
AND COLD AIR ALOFT MOVES OVERHEAD WITH SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS. IT`S POSSIBLE WE COULD HAVE MORE
THUNDERSTORM ACTIVITY FRIDAY AFTERNOON EAST OF THE CASCADES. IT`S
ALSO POSSIBLE SOME THUNDERSTORMS COULD PRODUCE GUSTY WINDS AND
SMALL HAIL. -PETRUCELLI
&&
.AVIATION...FOR THE 03/12Z TAF CYCLE...CONDITIONS WILL BE VFR
THROUGH THIS EVENING THEN ONSHORE FLOW WILL BRING MAINLY VFR CIGS
BUT LOCAL MVFR CIGS WITH MOUNTAIN OBSCURATION INTO SOUTHWEST OREGON
LATE TONIGHT INTO FRIDAY MORNING. /DW
&&
.MARINE...UPDATED 500 AM PDT THURSDAY 3 SEPTEMBER 2015...SMALL CRAFT
ADVISORY LEVEL NORTH WINDS AT THE LOW END OF CRITERIA WILL DEVELOP
SOUTH OF GOLD BEACH BEYOND 5 NM FROM SHORE LATE THIS MORNING. THESE
WINDS WILL REACH A PEAK IN THE EARLY EVENING THEN DIMINISH OVERNIGHT
BEFORE RETURNING TO ABOUT THE SAME STRENGTH FOR LATE FRIDAY MORNING
THROUGH FRIDAY EVENING. AFTER ANOTHER DECREASE IN WINDS LATE FRIDAY
NIGHT, WINDS WILL BECOME STRONGER DURING THE WEEKEND. WINDS WILL
STILL BE MODERATE SATURDAY BUT GALES ARE POSSIBLE IN THE SOUTHERN
OUTER WATERS WITH SMALL CRAFT WINDS ELSEWHERE SUNDAY INTO MONDAY.
WINDS ARE EXPECTED TO RETURN TO MODERATE STRENGTH BEYOND
MONDAY. /DW
&&
.PREV DISCUSSION... /ISSUED 351 AM PDT THU SEP 3 2015/
DISCUSSION...A COLD FRONT THAT MOVED THROUGH LATE WEDNESDAY HAS
LEFT MOST OF THE AREA 5 TO 10 DEGREES COOLER VERSUS THIS TIME VERSUS
YESTERDAY. EVENING SHIFT PUT UP A FROST ADVISORY FOR SOME OF THE
EAST SIDE. THE DAY SHIFT TODAY WILL NEED TO CONSIDER THE SAME FOR
TONIGHT AND FRIDAY NIGHT AS THE CENTER OF AN UNUSUALLY COLD UPPER
LOW DIVES IN OVERHEAD. THIS LOW WILL BRING THE COOLEST AIR OF THE
SEASON WITH A COLD CORE OF -25C AT 500 MILLIBARS. AS THE TROUGH
SWINGS EASTWARD AND SKIES CLEAR SATURDAY NIGHT INTO SUNDAY...
THERE WILL BE A THREAT FOR FREEZING MORNING TEMPERATURES ACROSS
MUCH OF THE LOWLANDS EAST OF THE CASCADES. A SPECIAL WEATHER
STATEMENT WILL COVER THIS UPCOMING POTENTIAL FOR FROST AND FREEZE
FOR AGRICULTURAL INTERESTS.
RAIN WITH THIS SYSTEM TODAY SHOULD REMAIN FAIRLY SLIM. THE 88D IS
CURRENTLY SHOWING SOME WEAK ECHOES STREAMING SOUTHWEST TO
NORTHEAST BETWEEN KLAMATH FALLS AND LAKEVIEW IN REGION OF COLDER
CLOUD TOPS BETWEEN -10 TO -15C IN THICKER CLOUD. PER THE RUC AND
HRRR FORECASTS, WE DID BUMP UP PROBABILITIES A BIT FOR A HUNDREDTH
OR TWO OUR THERE AROUND SOUTHERN LAKE COUNTY WITH SHORT WAVE
ENERGY OVERRIDING THE SLOWLY PROGRESSING FRONTAL ZONE. THIS SHOULD
TAPER OFF THIS EVENING WITH A FAIRLY UNEVENTFUL NIGHT IN STORE.
ACTIVITY WILL INCREASE FRIDAY WITH THE APPROACH OF THE DEEP UPPER
LOW FROM THE NORTH. FAIRLY STRONG SHORT WAVE ENERGY IS FORECAST TO
DIG THROUGH THE BASE OF THE TROUGH OVER SOUTHERN OREGON AND NORTHERN
CALIFORNIA FRIDAY AFTERNOON AND EVENING. WITH THE COLD AIR ALOFT,
NUMEROUS SHOWERS AND A SLIGHT CHANCE FOR THUNDERSTORMS WITH SOME
LOCALIZED MODERATE RAINS ARE IN STORE. THE BEST SHOT AT GOOD RAIN
WILL BE EAST OF THE CASCADES. DUE TO BUILDING CONFIDENCE BASED ON
SUPPORT FROM RECENT MODEL RUNS, HAVE ALSO BUMPED UP POPS A BIT
MORE IN THIS TIME FRAME.
SHOWERS WILL BE LINGERING INTO SATURDAY MORNING MAINLY FROM THE
CASCADES EAST. SNOW LEVELS EARLY SATURDAY SHOULD BOTTOM OUT BETWEEN
6000 AND 6500 FEET OVER THE CASCADES, AND MORE LIKE 7KFT IN
NORTHERN CALIFORNIA. SO, A LITTLE DUSTING ON THE HIGHER TERRAIN
LOOKS LIKELY. SOME UNCERTAINTY EXISTS FOR AREAS IN LAKE COUNTY
WHERE THE MORE SIGNIFICANT PRECIP WILL FALL. THE WARNERS INCLUDING
HART MTN AREA ABOVE 6500 FEET SHOULD BE AWARE OF THE POTENTIAL FOR
A LITTLE MORE SNOW THERE.
AS THE SYSTEM CLEARS OUT SATURDAY AFTERNOON AND NIGHT, THIS WILL
LEAVE SUNDAY MORNING WITH A FAIR POTENTIAL TO FREEZE IN MANY AREAS
OF WHAT LOOKS LIKE MAINLY LAKE AND MODOC COUNTIES. A WARMING TREND
LOOKS LIKELY THEREAFTER THROUGH LATE WEEK. STAVISH
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR
PZZ356-376.
SMALL CRAFT ADVISORY FROM 11 AM TO 11 PM PDT FRIDAY FOR PZZ376.
$$
AREA FORECAST DISCUSSION
NWS MEDFORD OR
351 AM PDT THU SEP 3 2015
.DISCUSSION...A COLD FRONT THAT MOVED THROUGH LATE WEDNESDAY HAS
LEFT MOST OF THE AREA 5 TO 10 DEGREES COOLER VERSUS THIS TIME VERSUS
YESTERDAY. EVENING SHIFT PUT UP A FROST ADVISORY FOR SOME OF THE
EAST SIDE. THE DAY SHIFT TODAY WILL NEED TO CONSIDER THE SAME FOR
TONIGHT AND FRIDAY NIGHT AS THE CENTER OF AN UNUSUALLY COLD UPPER
LOW DIVES IN OVERHEAD. THIS LOW WILL BRING THE COOLEST AIR OF THE
SEASON WITH A COLD CORE OF -25C AT 500 MILLIBARS. AS THE TROUGH
SWINGS EASTWARD AND SKIES CLEAR SATURDAY NIGHT INTO SUNDAY...
THERE WILL BE A THREAT FOR FREEZING MORNING TEMPERATURES ACROSS
MUCH OF THE LOWLANDS EAST OF THE CASCADES. A SPECIAL WEATHER
STATEMENT WILL COVER THIS UPCOMING POTENTIAL FOR FROST AND FREEZE
FOR AGRICULTURAL INTERESTS.
RAIN WITH THIS SYSTEM TODAY SHOULD REMAIN FAIRLY SLIM. THE 88D IS
CURRENTLY SHOWING SOME WEAK ECHOES STREAMING SOUTHWEST TO
NORTHEAST BETWEEN KLAMATH FALLS AND LAKEVIEW IN REGION OF COLDER
CLOUD TOPS BETWEEN -10 TO -15C IN THICKER CLOUD. PER THE RUC AND
HRRR FORECASTS, WE DID BUMP UP PROBABILITIES A BIT FOR A HUNDREDTH
OR TWO OUR THERE AROUND SOUTHERN LAKE COUNTY WITH SHORT WAVE
ENERGY OVERRIDING THE SLOWLY PROGRESSING FRONTAL ZONE. THIS SHOULD
TAPER OFF THIS EVENING WITH A FAIRLY UNEVENTFUL NIGHT IN STORE.
ACTIVITY WILL INCREASE FRIDAY WITH THE APPROACH OF THE DEEP UPPER
LOW FROM THE NORTH. FAIRLY STRONG SHORT WAVE ENERGY IS FORECAST TO
DIG THROUGH THE BASE OF THE TROUGH OVER SOUTHERN OREGON AND NORTHERN
CALIFORNIA FRIDAY AFTERNOON AND EVENING. WITH THE COLD AIR ALOFT,
NUMEROUS SHOWERS AND A SLIGHT CHANCE FOR THUNDERSTORMS WITH SOME
LOCALIZED MODERATE RAINS ARE IN STORE. THE BEST SHOT AT GOOD RAIN
WILL BE EAST OF THE CASCADES. DUE TO BUILDING CONFIDENCE BASED ON
SUPPORT FROM RECENT MODEL RUNS, HAVE ALSO BUMPED UP POPS A BIT
MORE IN THIS TIME FRAME.
SHOWERS WILL BE LINGERING INTO SATURDAY MORNING MAINLY FROM THE
CASCADES EAST. SNOW LEVELS EARLY SATURDAY SHOULD BOTTOM OUT BETWEEN
6000 AND 6500 FEET OVER THE CASCADES, AND MORE LIKE 7KFT IN
NORTHERN CALIFORNIA. SO, A LITTLE DUSTING ON THE HIGHER TERRAIN
LOOKS LIKELY. SOME UNCERTAINTY EXISTS FOR AREAS IN LAKE COUNTY
WHERE THE MORE SIGNIFICANT PRECIP WILL FALL. THE WARNERS INCLUDING
HART MTN AREA ABOVE 6500 FEET SHOULD BE AWARE OF THE POTENTIAL FOR
A LITTLE MORE SNOW THERE.
AS THE SYSTEM CLEARS OUT SATURDAY AFTERNOON AND NIGHT, THIS WILL
LEAVE SUNDAY MORNING WITH A FAIR POTENTIAL TO FREEZE IN MANY AREAS
OF WHAT LOOKS LIKE MAINLY LAKE AND MODOC COUNTIES. A WARMING TREND
LOOKS LIKELY THEREAFTER THROUGH LATE WEEK. STAVISH
&&
.AVIATION...FOR THE 03/06Z TAF CYCLE...ALONG THE COAST EXPECT
MAINLY VFR CONDITIONS WITH ISOLATED MVFR/ CIGS THROUGH EARLY THIS
MORNING...BECOMING VFR BY 18Z. INLAND, FOR AREAS WEST OF THE
CASCADES, CONDITIONS WILL BE MAINLY VFR BUT ONSHORE FLOW WILL
MAINTAIN SOME MID CLOUDS ALONG AND JUST WEST OF THE CASCADES LATE
TONIGHT AND EARLY THIS MORNING. THIS WILL BRING AREAS OF MOUNTAIN
OBSCURATION NEAR THE CASCADES. ALSO AREAS OF MVFR CIGS ARE
EXPECTED TO DEVELOP IN THE UMPQUA BASIN LATE TONIGHT INTO EARLY
THIS MORNING...WITH CLEARING AROUND 17Z. EAST OF THE CASCADES,
EXPECT SOME LIGHT SHOWERS AND AREAS OF MOUNTAIN OBSCURATIONS
THROUGH THE MORNING AS A FRONT SHIFTS EASTWARD OVER THE
AREA...WITH VFR IN THE AFTERNOON AND EVENING. /CC
&&
.MARINE...UPDATED 1030 PM PDT WEDNESDAY 2 SEPTEMBER 2015...A TROUGH
OF LOW PRESSURE WILL MOVE THROUGH THE WATERS TONIGHT THROUGH FRIDAY
WITH PERIODS OF SHOWERS POSSIBLE. IN ADDITION, THIS SYSTEM WILL
BRING A SLIGHT CHANCE OF THUNDERSTORMS OVER THE WATERS FRIDAY
MORNING. WINDS WILL INCREASE TONIGHT THROUGH THURSDAY...WITH SEAS
BECOMING A MIX OF SWELL AND SHORT PERIOD WIND WAVE BY THURSDAY
EVENING. SOME SMALLER LONGER PERIOD SWELLS WILL BE MIXED IN. THE
COASTAL WATERS WILL BE DOMINATED BY MODERATE TO STRONG NORTH WINDS
THURSDAY THROUGH THE WEEKEND...WITH SMALL CRAFT ADVISORY CONDITIONS
SOUTH OF CAPE BLANCO. THERE IS ENOUGH SUPPORT FROM MODELS TO BRING
SMALL CRAFT ADVISORY CONDITIONS INTO THE INNER WATERS SOUTH OF GOLD
BEACH THURSDAY AFTERNOON AND EVENING. MODERATE NORTH WINDS CONTINUE
FRIDAY INTO SATURDAY. THEN WINDS ARE FORECAST TO STRENGTHEN SUNDAY
INTO MONDAY WITH GALES POSSIBLE IN THE SOUTHERN OUTER WATERS. STRONG
NORTHERLY WINDS ARE LIKELY TO PERSIST THROUGH EARLY NEXT WEEK.
SK/CC
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...FROST ADVISORY UNTIL 8 AM PDT THIS MORNING FOR ORZ029>031.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING
TO 11 AM PDT FRIDAY FOR PZZ376.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 11 PM THIS EVENING
TO 11 AM PDT FRIDAY FOR PZZ376.
SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 11 PM PDT THIS
EVENING FOR PZZ356.
$$
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1116 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/...
AS THE SURFACE AND UPPER LEVEL HIGH SLIDES SOUTH ALONG THE NEW
ENGLAND COAST...IT IS FORCING A DEEP EASTERLY FLOW INTO THE AREA.
WEAK LOCAL FORCING...RESIDUAL INSTABILITY AND A GENERAL UPSLOPE
COMPONENT TO THE LOW LEVEL FLOW ARE ALL COMBINING TO KEEP SOME
SCATTERED SHOWERS AND THUNDERSTORMS FLOATING AROUND IN A RATHER
DISORGANIZED FASHION AS OF LATE EVENING.
THE HRRR KEEPS TRYING TO ORGANIZE A SMALL MCS WHICH IT TRACKS
THROUGH THE SOUTH CENTRAL MOUNTAINS BETWEEN ABOUT 5 AND 11Z. THIS
SEEMS OVERDONE AND WILL MORE LIKELY BE ISOLATED LEFT OVER
ACTIVITY... GIVEN THE NEGATIVE TREND IN OBSERVED CAPE AND THE
NORMAL DIURNAL DIE OFF TIME...AND EVEN COULD BE PORTRAYING AN
INCREASE IN LOW CLOUDS/MOISTURE THAT SHOULD START ADVECTING WEST
IN THE MARITIME FLOW.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
FOR SATURDAY MODEL MID LEVEL TEMPS ARE EXPECTED TO INCREASE TO
VALUES CLOSER TO WHAT WE NORMALLY SEE ACT AS AN EFFECTIVE CAP IN
THE LOCAL AREA. BETWEEN THAT AND MORE IN THE WAY OF LOW
CLOUDINESS...WE SHOULD BE COOLER IN THE LOW LEVELS AND WARMER
ALOFT WHICH WILL EQUATE TO LESS INSTABILITY AND A SMALLER CHANCE FOR
SHOWERS. THE BEST CHANCE FOR AN ISOLATED STORM WILL BE OVER
WESTERN AREAS DURING THE LATTER HALF OF THE DAY.
HIGHS WILL BE A FEW DEGREES COOLER THAN PREVIOUS DAYS AND
DEWPOINTS WILL EVEN NUDGE DOWN A BIT AS LOWER DEWPOINTS START TO
ADVECT IN FORM THE NORTHEAST.
&&
.LONG TERM /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 AMPLIFYING TROUGH ARE SIMPLY TOO MUDDY AT THIS TIME RANGE.
ONE THING MORE CERTAIN IN THIS MEDIUM RANGE FORECAST IS THE COOLING
TEMPS FOR THE LATTER HALF OF THE WEEK AND NEXT WEEKEND...WHEN BOTH
MAX AND MIN TEMPS COULD BE UP TO SEVERAL DEG F BELOW NORMAL
/ESPECIALLY OVER THE NRN AND WESTERN MTNS OF THE STATE...WHERE MORE
CLOUDS AND COOLER TEMPS ALOFT WILL BE FOUND/.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
05/03Z...COVERAGE OF SHOWERS/TSTMS HAS DIMINISHED CONSIDERABLY
SINCE 00Z. HOWEVER A FEW SMALL CLUSTERS STILL REMAIN OVER THE
SOUTH CENTRAL AIRSPACE /INVOF IPT AND AOO/. SO IT APPEARS THAT THE
COSPA/HRRR WAS NOT TOO FAR OFF ON LOCATION BUT TOO AGGRESSIVE WITH
SPATIAL COVERAGE. LATEST IR STLT AND SFC OBS CONFIRM LOW CIGS
DEVELOPING/SPREADING WWD INTO THE ERN TERMINALS A LITTLE EARLIER
THAN PREVIOUSLY FCST -- SO MOVED UP ONSET/TIMING OF MVFR CIGS.
THE MAIN CONCERN OVERNIGHT WILL BE DEVELOPING LOW CLOUDS AND FOG.
A MOIST LOW-LEVEL FLOW FROM THE SOUTHEAST BEHIND THE BACKDOOR COLD
FRONT WILL LIKELY PRODUCE MVFR TO IFR CONDS ACROSS MUCH OF THE
AIRSPACE INTO EARLY SATURDAY MORNING. CIGS MAY BE SLOW TO LIFT
AFTER DAYBREAK BUT EXPECT WIDESPREAD VFR TO RETURN BY THE AFTN.
SFC HIGH PRESSURE WILL BUILD INTO THE REGION FOR THE REST OF THE
WEEKEND AND PROVIDE MAINLY VFR FLYING THRU EARLY NEXT WEEK.
OUTLOOK...
SUN-TUE...PATCHY FOG IN THE MORNING...OTHERWISE VFR.
WED...COLD FROPA WITH SCT SHRA/TSRA.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...DANGELO/GARTNER
LONG TERM...LAMBERT
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1046 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/...
AS THE SURFACE AND UPPER LEVEL HIGH SLIDES SOUTH ALONG THE NEW
ENGLAND COAST...IT IS FORCING A DEEP EASTERLY FLOW INTO THE AREA.
WEAK LOCAL FORCING...RESIDUAL INSTABILITY AND A GENERAL UPSLOPE
COMPONENT TO THE LOW LEVEL FLOW ARE ALL COMBINING TO KEEP SOME
SCATTERED SHOWERS AND THUNDERSTORMS FLOATING AROUND IN A RATHER
DISORGANIZED FASHION AS OF LATE EVENING.
THE HRRR KEEPS TRYING TO ORGANIZE A SMALL MCS WHICH IT TRACKS
THROUGH THE SOUTH CENTRAL MOUNTAINS BETWEEN ABOUT 5 AND 11Z. THIS
SEEMS OVERDONE AND WILL MORE LIKELY BE ISOLATED LEFT OVER
ACTIVITY... GIVEN THE NEGATIVE TREND IN OBSERVED CAPE AND THE
NORMAL DIURNAL DIE OFF TIME...AND EVEN COULD BE PORTRAYING AN
INCREASE IN LOW CLOUDS/MOISTURE THAT SHOULD START ADVECTING WEST
IN THE MARITIME FLOW.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
FOR SATURDAY MODEL MID LEVEL TEMPS ARE EXPECTED TO INCREASE TO
VALUES CLOSER TO WHAT WE NORMALLY SEE ACT AS AN EFFECTIVE CAP IN
THE LOCAL AREA. BETWEEN THAT AND MORE IN THE WAY OF LOW
CLOUDINESS...WE SHOULD BE COOLER IN THE LOW LEVELS AND WARMER
ALOFT WHICH WILL EQUATE TO LESS INSTABILITY AND A SMALLER CHANCE FOR
SHOWERS. THE BEST CHANCE FOR AN ISOLATED STORM WILL BE OVER
WESTERN AREAS DURING THE LATTER HALF OF THE DAY.
HIGHS WILL BE A FEW DEGREES COOLER THAN PREVIOUS DAYS AND
DEWPOINTS WILL EVEN NUDGE DOWN A BIT AS LOWER DEWPOINTS START TO
ADVECT IN FORM THE NORTHEAST.
&&
.LONG TERM /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 AMPLIFYING TROUGH ARE SIMPLY TOO MUDDY AT THIS TIME RANGE.
ONE THING MORE CERTAIN IN THIS MEDIUM RANGE FORECAST IS THE COOLING
TEMPS FOR THE LATTER HALF OF THE WEEK AND NEXT WEEKEND...WHEN BOTH
MAX AND MIN TEMPS COULD BE UP TO SEVERAL DEG F BELOW NORMAL
/ESPECIALLY OVER THE NRN AND WESTERN MTNS OF THE STATE...WHERE MORE
CLOUDS AND COOLER TEMPS ALOFT WILL BE FOUND/.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
THE LOSS OF DAYTIME HEATING/INSTABILITY SHOULD LEAD TO GRADUAL
WEAKENING AND DISSIPATING TREND IN CONVECTIVE ACTIVITY THROUGH
LATE EVENING. THE COSPA/HRRR GUIDANCE IS CURIOUSLY AGGRESSIVE IN
MAINTAINING CONVECTIVE PCPN OVER THE SOUTH-CENTRAL AIRSPACE INTO
LATE TONIGHT...AND HAVE DISCOUNTED THIS FOR NOW AS BLYR BECOMES
MORE STABLE WITH TIME.
THE MAIN CONCERN OVERNIGHT WILL BE DEVELOPING LOW CLOUDS AND FOG.
A MOIST LOW-LEVEL FLOW FROM THE SOUTHEAST BEHIND THE BACKDOOR
COLD FRONT WILL LIKELY PRODUCE MVFR TO IFR CONDS ACROSS MUCH OF
THE AIRSPACE INTO EARLY SATURDAY MORNING. CIGS MAY BE SLOW TO LIFT
AFTER DAYBREAK BUT EXPECT WIDESPREAD VFR TO RETURN BY THE AFTN.
SFC HIGH PRESSURE WILL BUILD INTO THE REGION FOR THE REST OF THE
WEEKEND AND PROVIDE MAINLY VFR FLYING THRU EARLY NEXT WEEK.
OUTLOOK...
SUN-TUE...PATCHY FOG IN THE MORNING...OTHERWISE VFR.
WED...COLD FROPA WITH SCT SHRA/TSRA.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LAMBERT
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
810 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 AMPLIFYING TROUGH ARE SIMPLY TOO MUDDY AT THIS TIME RANGE.
ONE THING MORE CERTAIN IN THIS MEDIUM RANGE FORECAST IS THE COOLING
TEMPS FOR THE LATTER HALF OF THE WEEK AND NEXT WEEKEND...WHEN BOTH
MAX AND MIN TEMPS COULD BE UP TO SEVERAL DEG F BELOW NORMAL
/ESPECIALLY OVER THE NRN AND WESTERN MTNS OF THE STATE...WHERE MORE
CLOUDS AND COOLER TEMPS ALOFT WILL BE FOUND/.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
THE LOSS OF DAYTIME HEATING/INSTABILITY SHOULD LEAD TO GRADUAL
WEAKENING AND DISSIPATING TREND IN CONVECTIVE ACTIVITY THROUGH
LATE EVENING. THE COSPA/HRRR GUIDANCE IS CURIOUSLY AGGRESSIVE IN
MAINTAINING CONVECTIVE PCPN OVER THE SOUTH-CENTRAL AIRSPACE INTO
LATE TONIGHT...AND HAVE DISCOUNTED THIS FOR NOW AS BLYR BECOMES
MORE STABLE WITH TIME.
THE MAIN CONCERN OVERNIGHT WILL BE DEVELOPING LOW CLOUDS AND FOG.
A MOIST LOW-LEVEL FLOW FROM THE SOUTHEAST BEHIND THE BACKDOOR
COLD FRONT WILL LIKELY PRODUCE MVFR TO IFR CONDS ACROSS MUCH OF
THE AIRSPACE INTO EARLY SATURDAY MORNING. CIGS MAY BE SLOW TO LIFT
AFTER DAYBREAK BUT EXPECT WIDESPREAD VFR TO RETURN BY THE AFTN.
SFC HIGH PRESSURE WILL BUILD INTO THE REGION FOR THE REST OF THE
WEEKEND AND PROVIDE MAINLY VFR FLYING THRU EARLY NEXT WEEK.
OUTLOOK...
SUN-TUE...PATCHY FOG IN THE MORNING...OTHERWISE VFR.
WED...COLD FROPA WITH SCT SHRA/TSRA.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE/GARTNER
NEAR TERM...LA CORTE/GARTNER
SHORT TERM...DANGELO/GARTNER
LONG TERM...LAMBERT
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1035 PM EDT FRI SEP 4 2015
.SYNOPSIS...
A COOL AND MOIST WIND FLOW OFF THE ATLANTIC THIS WEEKEND WILL KEEP
CONSIDERABLE CLOUDINESS AND COOLER TEMPERATURES FOR OUR REGION.
EXPECT GRADUAL WARMING EARLY TO MIDDLE OF THE UPCOMING WEEK UNDER AN
UPPER RIDGE. A COLD FRONT AND UPPER TROUGH WILL ARRIVE AT THE END OF
THE WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 1030 PM...CONVECTION CONTINUES TO LINGER AND RE-FIRE ACROSS
THE AREA. HIRES GUIDANCE NOT HANDLING IT PARTICULARLY WELL BUT
CONTINUES TO HINT AT ADDITIONAL ROUNDS OF CONVECTION WORKING THEIR
WAY SOUTH ACROSS THE AREA AS THE SURFACE HIGH CONTINUES TO BUILD
TO THE NORTHEAST...PUSHING THE BACKDOOR FRONT INTO THE AREA. MADE
ADDITIONAL UPDATES TO POPS BUT THIS WILL LIKELY BE AN ONGOING
BATTLE ALL NIGHT.
AS OF 730 PM...HAVE SEEN AN INCREASE IN CONVECTIVE INTENSITY OVER
THE PAST HOUR OR SO AS STORMS START MOVING INTO AREAS NOT ALREADY
WORKED OVER BY PREVIOUS CONVECTION. HRRR AND OTHER CAM/HIRES
REFLECTIVITY GUIDANCE INDICATES ISOLATED STRONG TO POTENTIALLY
SEVERE CONVECTION WILL HANG AROUND THROUGH AROUND 06Z OR SO. WILL
CONTINUE TO ADJUST GRIDS BASED ON OBSERVED DATA
AS OF 430 PM...MADE SOME UPDATES TO SKY/POPS/WX BASED ON CURRENT
TRENDS. SEEING SOME NON-SEVERE DOWNBURSTS WITH THESE STORMS...
ESPECIALLY WITH THE AID OF THE TCLT TDWR. ISOLATED SEVERE STILL
DEFINITELY POSSIBLE...HAVE SEEN SOME REPORTS OF SEVERE WINDS AND
HAIL TO OUR SOUTH WHERE CAPE/DCAPE VALUES ARE A LITTLE HIGHER.
TRENDS INTO THE EVENING STILL LOOK GOOD BUT WILL UPDATE AS NECESSARY
THROUGH THE EVENING.
AS OF 230 PM...SATELLITE IMAGERY SHOWS ENHANCED CU OVER THE
RIDGETOPS AND RADAR IMAGERY SHOWS THAT DEEP CONVECTION HAS INITIATED
ACROSS PARTS OF NC AND ALONG THE BLUE RIDGE IN VA...AND DOWN ACROSS
THE AREA NEAR THE FALL LINE. COVERAGE SHOULD GRADUALLY EXPAND FROM
THERE. STILL THINK WE COULD SEE A FEW STORMS BECOME STRONG ENUF TO
PRODUCE DAMAGING WIND GUSTS NOW THAT WE HAVE REALIZED THE EXPECTED
ENVIRONMENT WITH DCAPE 1000+ J/KG. TEMPS LOOK GOOD.
THE NEXT 24 HOURS SHOULD SEE THE DEVELOPMENT OF A PSEUDO-WEDGE-LIKE
SCENARIO ACROSS THE WESTERN CAROLINAS. THE UPPER AIR PATTERN REMAINS
CONVOLUTED WITH AN OVERALL HIGH AMPLITUDE RIDGE ACROSS EASTERN NORTH
AMERICA...BUT WITH AN UPPER LOW CENTERED OFF THE SOUTHEAST COAST AND
WEAK CYCLONIC FLOW AT MID LEVELS ACROSS THE FCST AREA. WITHIN THIS
FLOW...A LARGE SURFACE HIGH WILL BE SUPPORTED TO OUR NE...LOOSELY
ANCHORED OVER NEW ENGLAND AND THE MARITIME PROVINCES. WHAT THIS DOES
IS PROVIDE A LOW LEVEL NE FLOW...WHICH IS NOT REALLY DAMMED ACROSS
THE AREA TO OUR N. HOWEVER...THE EASTERLY FLOW AND THE DEVELOPMENT
OF CONVECTIVE PRECIP ACROSS THE PIEDMONT AND FOOTHILLS OF VA AND
NRN NC MAY FORM A COOL POOL THAT OOZES SOUTH AND SOUTHWESTWARD
OVERNIGHT...PERHAPS ALONG CONVECTIVE OUTFLOWS. THIS IN EFFECT WILL
FORM A SORT OF IN-SITU WEDGE INTO THE FCST AREA...WHICH SHOULD
GRADUALLY PUSH S AND SW INTO SATURDAY MORNING. THE PROBLEM IS THE
E/NE FLOW IS FAIRLY DEEP AND THERE WILL NOT BE ANY ISENTROPIC LIFT
OR LLVL WARM ADVECTION OVER THE TOP OF A STABLE BOUNDARY LAYER TO
MAINTAIN IT. AS A RESULT...ON SATURDAY WE ARE LEFT WITH BASICALLY
A COOL AND CLOUDY NE FLOW NEAR THE SFC. THE MODELS PUSH PRECIP
PRODUCTION DOWN INTO NE GEORGIA AND ACROSS THE MTNS BY AFTERNOON.
WILL HEDGE AND KEEP AT LEAST A SLIGHT CHC OVER THE WRN NC PIEDMONT.
THIS WILL MAKE THE HIGH TEMP FCST TRICKY. NOT CONVINCED TEMPS
WILL REMAIN BELOW GUIDANCE...SO HAVE NUDGED THEM UP A BIT OVER
THE PIEDMONT.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AS OF 200 PM FRI...LITTLE IMPACTFUL CHANGE IS EXPECTED IN THE
OVERALL SFC/UPPER PATTERN OVER THE PERIOD. HIGH PRESSURE OVER THE
NE CONUS WILL WEAKEN SLOWLY AND MOVE OFFSHORE UNDER THE INFLUENCE
OF FALLING HEIGHTS OVER THE MIDWEST. NORTHEASTERLY TO EASTERLY
FLOW WILL CONTINUE INTO THE CAROLINAS ON THE SRN PERIPHERY OF
THE HIGH. THE MAIN EFFECT WILL BE TO MAINTAIN LOW TO MID LEVEL
MOISTURE TRANSPORT FROM THE ATLANTIC...BUT ONLY SLIGHT UPSLOPE
FORCING DUE TO THE WEAK WINDS. POPS ARE WARRANTED MAINLY ON ACCOUNT
OF INSTABILITY...BUT THE USUAL MODEL DIFFERENCES BETWEEN THE GFS
AND NAM ARE SEEN. THE NAM DEPICTS THE EASTERLY WINDS MAINTAINING
A MIXED LAYER ATOP THE BOUNDARY LAYER...FROM WHICH PARCELS WILL
REMAIN BUOYANT OVERNIGHT. GFS SHOWS THIS BEING LESS EFFECTIVE AND
ALSO SHOWS POORER MIDLEVEL LAPSE RATES. NEVERTHELESS SLIGHT CHANCE
NOCTURNAL POPS WITH SLIGHT FAVORITISM TOWARD THE BLUE RIDGE ARE
APPROPRIATE. AFTERNOON CAPE IS EXPECTED TO BE GREATER SUNDAY THAN
MONDAY AND SO THE HIGHEST OVERALL POPS ARE INCLUDED THEN.
MAX TEMPS WILL BE A DEGREE OR TWO BELOW CLIMO SUNDAY BUT REBOUND
TO ABOUT CLIMO ON MONDAY WITH AIRMASS MODIFICATION. MIN TEMPS WILL
BE SLIGHTLY ABOVE CLIMO WITH NOCTURNAL CLOUD COVER.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AT 150 PM EDT FRIDAY...STARTING MONDAY NIGHT THE 500MB PATTERN HAS
A SHALLOW RIDGE OVER THE SOUTHEAST STATES WITH A TROUGH AXIS OVER THE
WESTERN DAKOTAS AND PROGRESSING EAST IMPINGING ON THE SE RIDGE. THE
RIDGE WILL FLATTEN OUT THROUGH MID WEEK THEN THE TROUGH DIGS OVER
THE SE WITH AXIS BECOMING ESTABLISHED JUST WEST OF THE APPALACHIANS
BY LATE FRIDAY. RIDGE WILL BUILD AT WEEKS END OVER THE FAR WEST.
AT THE SURFACE...HIGH PRESSURE WILL BE OVER THE CAROLINAS AND MID
ATLANTIC TUESDAY THEN DRIFTS EAST AS COLD FRONT CROSSES THE MISS
VALLEY. THIS COLD FRONT REACHES THE OHIO VALLEY BY THURSDAY AND WILL
BE CROSSING OUR AREA BY FRIDAY. SCATTERED CONVECTION WILL INCREASE
AS THE FRONT GETS CLOSER LATE IN THE WEEK.
OVERALL...THE INSTABILITY WILL BE MODEST AT BEST. CAPE
VALUES AROUND 1000 ON THE GFS FOR PIEDMONT GA AND SC LATE
TUESDAY...WEAKER VALUES WED AND 700 TO 1000 THURSDAY AND FRIDAY.
WIND SPEEDS IN THE LOW TO MID LEVELS NOT EXCESSIVE AS H8GHER WINDS
AT THE END OF THE WEEK IN THE TROUGH. EVEN THEN THE 700MB WIND WILL
BE AROUND 20 KTS WHICH IS FAIRLY LIGHT.
TEMPS A LITTLE ABOVE NORMAL IN MID WEEK...DIPPING TO A LITTLE BELOW
NORMAL NEXT WEEKEND WITHIN THE TROUGH.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...FOR NOW...LOOKS LIKE CONVECTION HAS MOVED OUT OF
THE KCLT AREA. SKIES WILL BE CHAOTIC DUE TO CONVECTIVE DEBRIS
OVERNIGHT...THOUGH AS WITH PREVIOUS FORECAST GUIDANCE CONTINUES TO
SUGGEST A LOW CLOUD DECK MOVING INTO THE AREA FROM THE NE EARLY
IN THE MORNING. NE WINDS WILL HELP BRING THIS MOISTURE IN AND SO
KEPT TREND OF MVFR CIGS FOR A PERIOD LATE TONIGHT AND EARLY IN
THE MORNING. AFTER SUNRISE...LOW CLOUD BASE WILL GRADUALLY RISE
TO VFR AS BOUNDARY LAYER DEEPENS. ADDITIONAL SHOWERS OR STORMS
SHOULD DEVELOP WITH HEATING AROUND MIDDAY SO HAVE INTRODUCED PROB30
TSRA AGAIN.
ELSEWHERE...KGMU/KGSP/KAND HAVE BEST CHANCE OF CONVECTION FOR THE
NEXT HOUR OR SO BUT ALSO SEEING SOME STORMS UP NEAR KHKY SO WILL
HAVE TO CONTINUE TO MONITOR. AS MENTIONED ABOVE...CONTINUED TREND
OF MVFR CIGS FOR THE NORTHERN TAFS AS MOISTURE INCREASES FROM
THE NE...COULD ALSO SEE SOME SHRA BUT CONFIDENCE NOT AS HIGH ON
THIS. EXPECT VALLEY FOG TO FORM AT KAVL IN THE PRE-DAWN HOURS...MOST
LIKELY RESTRICTING VSBY TO MVFR...WITH OTHER SITES POSSIBLY SEEING
MVFR FOG DUE TO LOW-LEVEL MOISTURE REMAINING FROM CONVECTION THIS
EVENING. WIND SHOULD REMAIN N TO NE THRU THE PERIOD. ANOTHER ROUND
OF TSRA CAN BE EXPECTED WITH HEATING ON SATURDAY...WITH PROB30
COVERING THIS FOR NOW.
OUTLOOK...A MOIST EASTERLY FLOW WILL CONTINUE THRU SUNDAY...BRINGING
A GOOD CHANCE OF IFR/MVFR RESTRICTIONS SATURDAY NIGHT AND SUNDAY
MORNING. LIGHT PRECIP WILL REMAIN POSSIBLE. THE THREAT FOR
RESTRICTIONS WILL CONTINUE THRU SUNDAY NIGHT. DRY AIR WORKING IN
FROM THE E ON MONDAY WILL BEGIN TO DIMINISH THE THREAT FOR EARLY
NEXT WEEK.
CONFIDENCE TABLE...
02-08Z 08-14Z 14-20Z 20-00Z
KCLT HIGH 100% HIGH 90% HIGH 84% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 98% HIGH 100%
KAVL HIGH 100% HIGH 89% HIGH 96% HIGH 100%
KHKY HIGH 100% HIGH 88% HIGH 83% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 91% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...PM/TDP
SHORT TERM...WIMBERLEY
LONG TERM...DEO
AVIATION...TDP
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
747 PM EDT FRI SEP 4 2015
.SYNOPSIS...
A COOL AND MOIST WIND FLOW OFF THE ATLANTIC THIS WEEKEND WILL KEEP
CONSIDERABLE CLOUDINESS AND COOLER TEMPERATURES FOR OUR REGION.
EXPECT GRADUAL WARMING EARLY TO MIDDLE OF THE UPCOMING WEEK UNDER AN
UPPER RIDGE. A COLD FRONT AND UPPER TROUGH WILL ARRIVE AT THE END OF
THE WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 730 PM...HAVE SEEN AN INCREASE IN CONVECTIVE INTENSITY OVER
THE PAST HOUR OR SO AS STORMS START MOVING INTO AREAS NOT ALREADY
WORKED OVER BY PREVIOUS CONVECTION. HRRR AND OTHER CAM/HIRES
REFLECTIVITY GUIDANCE INDICATES ISOLATED STRONG TO POTENTIALLY
SEVERE CONVECTION WILL HANG AROUND THROUGH AROUND 06Z OR SO. WILL
CONTINUE TO ADJUST GRIDS BASED ON OBSERVED DATA
AS OF 430 PM...MADE SOME UPDATES TO SKY/POPS/WX BASED ON CURRENT
TRENDS. SEEING SOME NON-SEVERE DOWNBURSTS WITH THESE STORMS...
ESPECIALLY WITH THE AID OF THE TCLT TDWR. ISOLATED SEVERE STILL
DEFINITELY POSSIBLE...HAVE SEEN SOME REPORTS OF SEVERE WINDS AND
HAIL TO OUR SOUTH WHERE CAPE/DCAPE VALUES ARE A LITTLE HIGHER.
TRENDS INTO THE EVENING STILL LOOK GOOD BUT WILL UPDATE AS NECESSARY
THROUGH THE EVENING.
AS OF 230 PM...SATELLITE IMAGERY SHOWS ENHANCED CU OVER THE
RIDGETOPS AND RADAR IMAGERY SHOWS THAT DEEP CONVECTION HAS INITIATED
ACROSS PARTS OF NC AND ALONG THE BLUE RIDGE IN VA...AND DOWN ACROSS
THE AREA NEAR THE FALL LINE. COVERAGE SHOULD GRADUALLY EXPAND FROM
THERE. STILL THINK WE COULD SEE A FEW STORMS BECOME STRONG ENUF TO
PRODUCE DAMAGING WIND GUSTS NOW THAT WE HAVE REALIZED THE EXPECTED
ENVIRONMENT WITH DCAPE 1000+ J/KG. TEMPS LOOK GOOD.
THE NEXT 24 HOURS SHOULD SEE THE DEVELOPMENT OF A PSEUDO-WEDGE-LIKE
SCENARIO ACROSS THE WESTERN CAROLINAS. THE UPPER AIR PATTERN REMAINS
CONVOLUTED WITH AN OVERALL HIGH AMPLITUDE RIDGE ACROSS EASTERN NORTH
AMERICA...BUT WITH AN UPPER LOW CENTERED OFF THE SOUTHEAST COAST AND
WEAK CYCLONIC FLOW AT MID LEVELS ACROSS THE FCST AREA. WITHIN THIS
FLOW...A LARGE SURFACE HIGH WILL BE SUPPORTED TO OUR NE...LOOSELY
ANCHORED OVER NEW ENGLAND AND THE MARITIME PROVINCES. WHAT THIS DOES
IS PROVIDE A LOW LEVEL NE FLOW...WHICH IS NOT REALLY DAMMED ACROSS
THE AREA TO OUR N. HOWEVER...THE EASTERLY FLOW AND THE DEVELOPMENT
OF CONVECTIVE PRECIP ACROSS THE PIEDMONT AND FOOTHILLS OF VA AND
NRN NC MAY FORM A COOL POOL THAT OOZES SOUTH AND SOUTHWESTWARD
OVERNIGHT...PERHAPS ALONG CONVECTIVE OUTFLOWS. THIS IN EFFECT WILL
FORM A SORT OF IN-SITU WEDGE INTO THE FCST AREA...WHICH SHOULD
GRADUALLY PUSH S AND SW INTO SATURDAY MORNING. THE PROBLEM IS THE
E/NE FLOW IS FAIRLY DEEP AND THERE WILL NOT BE ANY ISENTROPIC LIFT
OR LLVL WARM ADVECTION OVER THE TOP OF A STABLE BOUNDARY LAYER TO
MAINTAIN IT. AS A RESULT...ON SATURDAY WE ARE LEFT WITH BASICALLY
A COOL AND CLOUDY NE FLOW NEAR THE SFC. THE MODELS PUSH PRECIP
PRODUCTION DOWN INTO NE GEORGIA AND ACROSS THE MTNS BY AFTERNOON.
WILL HEDGE AND KEEP AT LEAST A SLIGHT CHC OVER THE WRN NC PIEDMONT.
THIS WILL MAKE THE HIGH TEMP FCST TRICKY. NOT CONVINCED TEMPS
WILL REMAIN BELOW GUIDANCE...SO HAVE NUDGED THEM UP A BIT OVER
THE PIEDMONT.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AS OF 200 PM FRI...LITTLE IMPACTFUL CHANGE IS EXPECTED IN THE
OVERALL SFC/UPPER PATTERN OVER THE PERIOD. HIGH PRESSURE OVER THE
NE CONUS WILL WEAKEN SLOWLY AND MOVE OFFSHORE UNDER THE INFLUENCE
OF FALLING HEIGHTS OVER THE MIDWEST. NORTHEASTERLY TO EASTERLY
FLOW WILL CONTINUE INTO THE CAROLINAS ON THE SRN PERIPHERY OF
THE HIGH. THE MAIN EFFECT WILL BE TO MAINTAIN LOW TO MID LEVEL
MOISTURE TRANSPORT FROM THE ATLANTIC...BUT ONLY SLIGHT UPSLOPE
FORCING DUE TO THE WEAK WINDS. POPS ARE WARRANTED MAINLY ON ACCOUNT
OF INSTABILITY...BUT THE USUAL MODEL DIFFERENCES BETWEEN THE GFS
AND NAM ARE SEEN. THE NAM DEPICTS THE EASTERLY WINDS MAINTAINING
A MIXED LAYER ATOP THE BOUNDARY LAYER...FROM WHICH PARCELS WILL
REMAIN BUOYANT OVERNIGHT. GFS SHOWS THIS BEING LESS EFFECTIVE AND
ALSO SHOWS POORER MIDLEVEL LAPSE RATES. NEVERTHELESS SLIGHT CHANCE
NOCTURNAL POPS WITH SLIGHT FAVORITISM TOWARD THE BLUE RIDGE ARE
APPROPRIATE. AFTERNOON CAPE IS EXPECTED TO BE GREATER SUNDAY THAN
MONDAY AND SO THE HIGHEST OVERALL POPS ARE INCLUDED THEN.
MAX TEMPS WILL BE A DEGREE OR TWO BELOW CLIMO SUNDAY BUT REBOUND
TO ABOUT CLIMO ON MONDAY WITH AIRMASS MODIFICATION. MIN TEMPS WILL
BE SLIGHTLY ABOVE CLIMO WITH NOCTURNAL CLOUD COVER.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AT 150 PM EDT FRIDAY...STARTING MONDAY NIGHT THE 500MB PATTERN HAS
A SHALLOW RIDGE OVER THE SOUTHEAST STATES WITH A TROUGH AXIS OVER THE
WESTERN DAKOTAS AND PROGRESSING EAST IMPINGING ON THE SE RIDGE. THE
RIDGE WILL FLATTEN OUT THROUGH MID WEEK THEN THE TROUGH DIGS OVER
THE SE WITH AXIS BECOMING ESTABLISHED JUST WEST OF THE APPALACHIANS
BY LATE FRIDAY. RIDGE WILL BUILD AT WEEKS END OVER THE FAR WEST.
AT THE SURFACE...HIGH PRESSURE WILL BE OVER THE CAROLINAS AND MID
ATLANTIC TUESDAY THEN DRIFTS EAST AS COLD FRONT CROSSES THE MISS
VALLEY. THIS COLD FRONT REACHES THE OHIO VALLEY BY THURSDAY AND WILL
BE CROSSING OUR AREA BY FRIDAY. SCATTERED CONVECTION WILL INCREASE
AS THE FRONT GETS CLOSER LATE IN THE WEEK.
OVERALL...THE INSTABILITY WILL BE MODEST AT BEST. CAPE
VALUES AROUND 1000 ON THE GFS FOR PIEDMONT GA AND SC LATE
TUESDAY...WEAKER VALUES WED AND 700 TO 1000 THURSDAY AND FRIDAY.
WIND SPEEDS IN THE LOW TO MID LEVELS NOT EXCESSIVE AS H8GHER WINDS
AT THE END OF THE WEEK IN THE TROUGH. EVEN THEN THE 700MB WIND WILL
BE AROUND 20 KTS WHICH IS FAIRLY LIGHT.
TEMPS A LITTLE ABOVE NORMAL IN MID WEEK...DIPPING TO A LITTLE BELOW
NORMAL NEXT WEEKEND WITHIN THE TROUGH.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...SEEING ANOTHER ROUND OF CONVECTION BEGINNING TO MOVE
TOWARD THE KCLT AREA...SO CONTINUED TEMPO WORDING FOR ANOTHER
COUPLE OF HOURS. SKIES WILL BE CHAOTIC DUE TO CONVECTIVE DEBRIS
OVERNIGHT...THOUGH AS WITH PREVIOUS FORECAST GUIDANCE CONTINUES TO
SUGGEST A LOW CLOUD DECK MOVING INTO THE AREA FROM THE NE EARLY
IN THE MORNING. NE WINDS WILL HELP BRING THIS MOISTURE IN AND SO
KEPT TREND OF MVFR CIGS FOR A PERIOD LATE TONIGHT AND EARLY IN
THE MORNING. AFTER SUNRISE...LOW CLOUD BASE WILL GRADUALLY RISE
TO VFR AS BOUNDARY LAYER DEEPENS. ADDITIONAL SHOWERS OR STORMS
SHOULD DEVELOP WITH HEATING AROUND MIDDAY SO HAVE INTRODUCED PROB30
TSRA AGAIN.
ELSEWHERE...KGMU/KGSP/KAND HAVE BEST CHANCE OF CONVECTION FOR THE
NEXT HOUR OR SO BUT ALSO SEEING SOME STORMS UP NEAR KHKY SO WILL
HAVE TO CONTINUE TO MONITOR. AS MENTIONED ABOVE...CONTINUED TREND
OF MVFR CIGS FOR THE NORTHERN TAFS AS MOISTURE INCREASES FROM
THE NE...COULD ALSO SEE SOME SHRA BUT CONFIDENCE NOT AS HIGH ON
THIS. EXPECT VALLEY FOG TO FORM AT KAVL IN THE PRE-DAWN HOURS...MOST
LIKELY RESTRICTING VSBY TO MVFR...WITH OTHER SITES POSSIBLY SEEING
MVFR FOG DUE TO LOW-LEVEL MOISTURE REMAINING FROM CONVECTION THIS
EVENING. WIND SHOULD REMAIN N TO NE THRU THE PERIOD. ANOTHER ROUND
OF TSRA CAN BE EXPECTED WITH HEATING ON SATURDAY...WITH PROB30
COVERING THIS FOR NOW.
OUTLOOK...A MOIST EASTERLY FLOW WILL CONTINUE THRU SUNDAY...BRINGING
A GOOD CHANCE OF IFR/MVFR RESTRICTIONS SATURDAY NIGHT AND SUNDAY
MORNING. LIGHT PRECIP WILL REMAIN POSSIBLE. THE THREAT FOR
RESTRICTIONS WILL CONTINUE THRU SUNDAY NIGHT. DRY AIR WORKING IN
FROM THE E ON MONDAY WILL BEGIN TO DIMINISH THE THREAT FOR EARLY
NEXT WEEK.
CONFIDENCE TABLE...
23-05Z 05-11Z 11-17Z 17-18Z
KCLT HIGH 100% HIGH 100% MED 62% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% MED 62% HIGH 100%
KHKY HIGH 100% HIGH 100% MED 62% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 83% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...PM/TDP
SHORT TERM...WIMBERLEY
LONG TERM...DEO
AVIATION...TDP
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1009 AM CDT THU SEP 3 2015
.DISCUSSION...
SKIES ARE MOSTLY SUNNY ACROSS THE FORECAST AREA THIS MORNING WITH
TEMPERATURES MAINLY IN THE LOW TO MID 80S. LATEST HRRR MODEL STILL
SHOWS SOME THUNDERSTORM DEVELOPMENT IS POSSIBLE THIS AFTERNOON
OVER EASTERN SECTIONS OF THE FORECAST AREA. WILL UPDATE FORECAST
TO REMOVE MORNING WORDING WITH NO BIG CHANGES NEEDED.
ARS
&&
.PREV DISCUSSION... /ISSUED 618 AM CDT THU SEP 3 2015/
DISCUSSION...
AN UPPER LEVEL SHEAR AXIS THAT HAS PERSISTED ACROSS THE MID SOUTH
OVER THE PAST FEW DAYS HAS SHIFTED EAST THIS MORNING AND NOW
RESIDES ACROSS THE EASTERN HALF OF THE FORECAST AREA. DAYTIME
HEATING AND WEAK LIFT ASSOCIATED WITH THIS UPPER TROUGH WILL LEAD
TO MORE ISOLATED SHOWERS AND THUNDERSTORMS THIS AFTERNOON ACROSS
WEST TENNESSEE...NEAR THE TENNESSEE RIVER...AND NORTHEAST
MISSISSIPPI. ELSEWHERE...UPPER LEVEL RIDGING WILL BUILD FROM THE
WEST WITH DRIER MID LEVEL AIR AND SUBSIDENCE WHICH SHOULD
SUPPRESS MOST CONVECTION. HOT AND HUMID CONDITIONS WILL CONTINUE
WITH MOST LOCATIONS REACHING INTO THE LOWER TO MIDDLE 90S THIS
AFTERNOON WITH DEWPOINTS NEAR 70 DEGREES. HEAT INDEX VALUES WILL
RISE INTO THE LOWER 100S IN MANY AREAS MAKING CONDITIONS FEEL
UNCOMFORTABLY HOT FOR THIS TIME OF YEAR.
UPPER LEVEL RIDGING SHOULD BUILD EAST OVER THE ENTIRE MID SOUTH
FOR FRIDAY AND CONTINUE TO CONTROL THE WEATHER CONDITIONS THROUGH
THE WEEKEND INTO EARLY NEXT WEEK. PRIMARILY DRY WEATHER ALONG WITH
A CONTINUATION OF HOT AND HUMID CONDITIONS SHOULD CONTINUE
THROUGH NEXT MONDAY. HIGH TEMPERATURES SHOULD REMAIN IN THE LOWER
TO MIDDLE 90S WITH LOWS IN THE UPPER 60S TO MIDDLE 70S. HEAT INDEX
VALUES SHOULD CONTINUE TO EXCEED 100 DEGREES EACH AFTERNOON IN
MANY LOCATIONS.
THE UPPER RIDGE SHOULD BREAK DOWN BY NEXT TUESDAY ALLOWING A SERIES
OF UPPER LEVEL SHORTWAVE DISTURBANCES TO PASS ACROSS THE REGION
THROUGH THE MIDDLE OF NEXT WEEK. A COLD FRONT SHOULD ALSO MOVE
SOUTH AND STALL ACROSS THE REGION BY THE END OF THE EXTENDED
FORECAST PERIOD. THERE REMAINS PLENTY OF MODEL DIFFERENCES THROUGH
THIS TIME PERIOD...SO TOOK A MODEL BLEND AND INCREASED CHANCES FOR
SHOWERS AND THUNDERSTORMS. TEMPERATURES SHOULD DROP BACK TO NEAR
NORMAL VALUES BUT WITH CONTINUED HUMID CONDITIONS.
JLH
&&
.AVIATION...
12Z TAF SET
VFR WEATHER WILL PREVAIL THIS PERIOD WITH PATCHY FOG REDEVELOPING
AT MKL AND TUP LATE. AN ISOLATED SHOWER NEAR TUP IS ALSO POSSIBLE
THROUGHOUT THE AFTERNOON. CALM OR LIGHT WINDS THROUGH THE PERIOD.
JAB
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1229 PM CDT THU SEP 3 2015
.AVIATION...
VFR LEVEL CIGS WILL HANG ON FOR A FEW MORE HOURS IN AUSTIN AND SAN
ANTONIO. WINDS WILL PICK UP TO AROUND 10 KTS FROM THE SOUTHEAST AT
ALL TERMINALS THIS AFTERNOON. DEEP LAYER SOUTHEASTERLY FLOW WILL
CONTINUE THROUGH THE PERIOD AND MVFR CIGS WILL DEVELOP AGAIN
OVERNIGHT AT ALL TERMINALS. IMPROVEMENT TO VFR WILL COME LATE
MORNING FRIDAY.
&&
.PREV DISCUSSION... /ISSUED 1002 AM CDT THU SEP 3 2015/
UPDATE...NO SIGNIFICANT UPDATES THIS MORNING WITH TODAYS FORECAST
ON TRACK WEATHER AND TEMPERATURE WISE. ONE SMALL ADJUSTMENT MADE
WAS SLIGHTLY REDUCING THE 30% POP IN LAVACA AND FAYETTE COUNTIES
TO 20% AND SHIFTING THE 30% AREA INTO KARNES COUNTY THROUGH 1PM.
THIS SHIFTING WAS DUE TO ONGOING RADAR TRENDS. HOURLY DEWPOINTS
WERE ALSO INCREASED ACROSS EASTERN LOCATIONS TO BETTER MATCH
OBSERVATIONS. UPDATES ARE OUT AND MORE DETAILS CAN BE FOUND BELOW
IN THE UPDATED DISCUSSION.
DISCUSSION... SOME SHOWERS ARE ONGOING ALONG THE COAST AND EXTEND
INLAND INTO DEWITT AND KARNES COUNTY THIS MORNING. ADDITIONAL
ISOLATED TO SCATTERED SHOWERS WILL BE LIKELY THROUGH THE AFTERNOON
PRIMARILY EAST OF THE I-35/37 CORRIDOR WHERE THE SEA-BREEZE
ACTIVITY WILL BE MORE PRONOUNCED. WATER VAPOR AND MID TO UPPER
LEVEL RAP ANALYSIS DEPICTS A CLOSED CUT-OFF LOW OVER THE GULF OF
MEXICO SE OF THE TEXAS COAST. THIS FEATURE MAY BE JUST DISTANT
ENOUGH NOT TO HAVE TO MUCH BEARING ON OUR WEATHER TODAY OTHER THAN
DEEPER LEVEL STEERING FLOW FROM THE EAST. THIS FLOW MAY HELP SOME
SEA-BREEZE ACTIVITY PUSH FROM THE EAST TO WEST TOWARDS THE 35
CORRIDOR THIS AFTERNOON AND EARLY EVENING. HOWEVER...OVERALL
CHANCES REMAIN LOW WITH 20-30%. LOW 800-500MB LAPSE RATES AND A
WARM NOSE NEAR 500MB WILL HAMPER DEEPER DEVELOPMENT OF THE
CONVECTION AND THUNDERSTORMS MAY BE HARD TO COME BY IN THIS
ENVIRONMENT. AN UPDATE DURING THE AFTN MAY REMOVE THE CURRENT
THUNDER WORDING AND BE REPLACED WITH GENERAL SHOWERS INSTEAD.
PREV DISCUSSION... /ISSUED 650 AM CDT THU SEP 3 2015/
AVIATION...
STRATUS CLOUDS CONTINUE TO DEVELOP THIS MORNING...WITH MVFR CIGS
ALREADY IN PLACE ACROSS MOST AREAS. STILL THINK THERE IS SOME
OPPORTUNITY FOR IFR CIGS FOR THE NEXT FEW HOURS AND WILL MENTION
TEMPO GROUPS ALONG THE I-35 CORRIDOR THROUGH 15Z. IMPROVING
CONDITIONS ARE IN STORE AFTER 16Z-17Z WITH VFR CONDITIONS
RETURNING TO ALL TERMINALS. ISOLATED CONVECTION IS STILL POSSIBLE
TODAY...BUT GIVEN LACK OF COVERAGE...WILL NOT MENTION IN THE
FORECAST AT THIS TIME. LOW CLOUDS WILL DEVELOP AFTER LATE TONIGHT
INTO FRIDAY MORNING...WITH MVFR CIGS EXPECTED AFTER 04/08Z. WINDS
WILL GENERALLY REMAIN FROM THE EAST AND SOUTHEAST AT OR BELOW
10KTS THROUGH THE PERIOD.
PREV DISCUSSION... /ISSUED 419 AM CDT THU SEP 3 2015/
SHORT TERM (TODAY THROUGH FRIDAY)...
WV IMAGERY AND UPPER AIR ANALYSES SHOW THAT THE WEAK SHEAR AXIS
AND ASSOCIATED TROUGH THAT STRETCHES FROM THE LOWER MISSISSIPPI
RIVER VALLEY TO THE SE TX AND LA GULF COAST CONTINUES TO WEAKEN.
ISOLATED SHOWERS AND THUNDERSTORMS ARE FORMING OVER THE GULF AND
MOVING ONSHORE...BUT THE COVERAGE IS LOWER THAN THE LAST FEW
NIGHTS. MOST OF THESE SHOWERS WILL DISSIPATE...BUT A ROGUE
SHOWER OR TWO MAY MOVE INTO OUR SE COUNTIES TOWARDS DAYBREAK. LOW
STRATUS HAS BEEN SLOWER TO DEVELOP TONIGHT THAN THE PREVIOUS FEW
EVENINGS...BUT STILL EXPECT THEM TO MOVE IN WITHIN THE NEXT FEW
HOURS AND PERSIST FOR A FEW HOURS AFTER SUNRISE TODAY AND FRIDAY.
MODELS ARE CONSISTENT IN BUILDING AND INTENSIFYING THE UPPER
LEVEL RIDGE OVER THE SOUTHERN PLAINS TODAY AND FRIDAY AS AN
INVERTED TROUGH BREAKS OFF FROM THE PROGRESSIVE TROUGH AND
RETROGRADES UNDER THE RIDGE AS IT WEAKENS. THIS WILL HELP CAUSE A
0.2-0.3 INCH SURGE IN PWAT VALUES AND SLIGHTLY DEEPER CONVERGENCE
WITH THE SEA BREEZE THAN OCCURRED ON WEDNESDAY...ALLOWING FOR
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS IN THE COASTAL
PLAINS THAT WILL DISSIPATE AS THEY MOVE INTO THE I-35 CORRIDOR.
MODELS HAVE GENERALLY BACKED OFF FROM SHOWERS MOVING INTO THE HILL
COUNTRY EXCEPT FOR THE ECMWF AND A FEW HI-RES MODELS FOR FRIDAY.
LONG TERM (FRIDAY NIGHT THROUGH WEDNESDAY)...
THE UPPER LEVEL RIDGE WILL CONTINUE TO INTENSIFY THROUGH THE
WEEKEND AS THE RETROGRADING SHEAR AXIS DISSIPATES. THIS WILL LEAD
TO HOT AND GENERALLY DRY DAYS ASIDE FROM ISOLATED AFTERNOON
SHOWERS AND THUNDERSTORMS IN THE COASTAL PLAINS ON SATURDAY. HEAT
INDEX VALUES WILL RISE INTO THE 100-105 RANGE EVERYWHERE EXCEPT
THE COUNTRY FOR ALL OF LABOR DAY WEEKEND...WITH HIGH TEMPS IN THE
MID-TO-UPPER 90S EXCEPT FOR A FEW SPOTS IN THE RIO GRANDE PLAINS
THAT REACH THE CENTURY MARK. THE RIDGE GRADUALLY BEGINS TO WEAKEN
AND SLIDE TO THE WEST BY WEDNESDAY...WHICH MAY ALLOW A WEAK FRONT
TO MOVE INTO THE REGION LATE THURSDAY INTO FRIDAY JUST PAST THE
FORECAST PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 73 95 75 97 76 / 20 20 10 10 -
AUSTIN BERGSTROM INTL AIRPORT 72 94 73 96 73 / 20 20 10 10 -
NEW BRAUNFELS MUNI AIRPORT 73 96 74 97 75 / 20 20 10 10 -
BURNET MUNI AIRPORT 73 94 73 95 74 / 10 10 10 10 -
DEL RIO INTL AIRPORT 75 97 76 98 77 / 10 10 10 10 -
GEORGETOWN MUNI AIRPORT 73 94 75 95 75 / 10 10 10 10 -
HONDO MUNI AIRPORT 73 96 74 97 73 / 10 10 10 10 -
SAN MARCOS MUNI AIRPORT 73 94 75 96 74 / 20 20 10 10 -
LA GRANGE - FAYETTE REGIONAL 73 94 75 95 76 / 30 20 10 20 10
SAN ANTONIO INTL AIRPORT 74 95 76 96 76 / 20 10 10 10 -
STINSON MUNI AIRPORT 74 96 76 97 75 / 20 10 10 10 -
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...05
SYNOPTIC/GRIDS...ALLEN
PUBLIC SERVICE/DATA COLLECTION...30
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1002 AM CDT THU SEP 3 2015
.UPDATE...NO SIGNIFICANT UPDATES THIS MORNING WITH TODAYS FORECAST
ON TRACK WEATHER AND TEMPERATURE WISE. ONE SMALL ADJUSTMENT MADE
WAS SLIGHTLY REDUCING THE 30% POP IN LAVACA AND FAYETTE COUNTIES
TO 20% AND SHIFTING THE 30% AREA INTO KARNES COUNTY THROUGH 1PM.
THIS SHIFTING WAS DUE TO ONGOING RADAR TRENDS. HOURLY DEWPOINTS
WERE ALSO INCREASED ACROSS EASTERN LOCATIONS TO BETTER MATCH
OBSERVATIONS. UPDATES ARE OUT AND MORE DETAILS CAN BE FOUND BELOW
IN THE UPDATED DISCUSSION.
&&
.DISCUSSION... SOME SHOWERS ARE ONGOING ALONG THE COAST AND EXTEND
INLAND INTO DEWITT AND KARNES COUNTY THIS MORNING. ADDITIONAL
ISOLATED TO SCATTERED SHOWERS WILL BE LIKELY THROUGH THE AFTERNOON
PRIMARILY EAST OF THE I-35/37 CORRIDOR WHERE THE SEA-BREEZE
ACTIVITY WILL BE MORE PRONOUNCED. WATER VAPOR AND MID TO UPPER
LEVEL RAP ANALYSIS DEPICTS A CLOSED CUT-OFF LOW OVER THE GULF OF
MEXICO SE OF THE TEXAS COAST. THIS FEATURE MAY BE JUST DISTANT
ENOUGH NOT TO HAVE TO MUCH BEARING ON OUR WEATHER TODAY OTHER THAN
DEEPER LEVEL STEERING FLOW FROM THE EAST. THIS FLOW MAY HELP SOME
SEA-BREEZE ACTIVITY PUSH FROM THE EAST TO WEST TOWARDS THE 35
CORRIDOR THIS AFTERNOON AND EARLY EVENING. HOWEVER...OVERALL
CHANCES REMAIN LOW WITH 20-30%. LOW 800-500MB LAPSE RATES AND A
WARM NOSE NEAR 500MB WILL HAMPER DEEPER DEVELOPMENT OF THE
CONVECTION AND THUNDERSTORMS MAY BE HARD TO COME BY IN THIS
ENVIRONMENT. AN UPDATE DURING THE AFTN MAY REMOVE THE CURRENT
THUNDER WORDING AND BE REPLACED WITH GENERAL SHOWERS INSTEAD.
&&
.PREV DISCUSSION... /ISSUED 650 AM CDT THU SEP 3 2015/
AVIATION...
STRATUS CLOUDS CONTINUE TO DEVELOP THIS MORNING...WITH MVFR CIGS
ALREADY IN PLACE ACROSS MOST AREAS. STILL THINK THERE IS SOME
OPPORTUNITY FOR IFR CIGS FOR THE NEXT FEW HOURS AND WILL MENTION
TEMPO GROUPS ALONG THE I-35 CORRIDOR THROUGH 15Z. IMPROVING
CONDITIONS ARE IN STORE AFTER 16Z-17Z WITH VFR CONDITIONS
RETURNING TO ALL TERMINALS. ISOLATED CONVECTION IS STILL POSSIBLE
TODAY...BUT GIVEN LACK OF COVERAGE...WILL NOT MENTION IN THE
FORECAST AT THIS TIME. LOW CLOUDS WILL DEVELOP AFTER LATE TONIGHT
INTO FRIDAY MORNING...WITH MVFR CIGS EXPECTED AFTER 04/08Z. WINDS
WILL GENERALLY REMAIN FROM THE EAST AND SOUTHEAST AT OR BELOW
10KTS THROUGH THE PERIOD.
PREV DISCUSSION... /ISSUED 419 AM CDT THU SEP 3 2015/
SHORT TERM (TODAY THROUGH FRIDAY)...
WV IMAGERY AND UPPER AIR ANALYSES SHOW THAT THE WEAK SHEAR AXIS
AND ASSOCIATED TROUGH THAT STRETCHES FROM THE LOWER MISSISSIPPI
RIVER VALLEY TO THE SE TX AND LA GULF COAST CONTINUES TO WEAKEN.
ISOLATED SHOWERS AND THUNDERSTORMS ARE FORMING OVER THE GULF AND
MOVING ONSHORE...BUT THE COVERAGE IS LOWER THAN THE LAST FEW
NIGHTS. MOST OF THESE SHOWERS WILL DISSIPATE...BUT A ROGUE
SHOWER OR TWO MAY MOVE INTO OUR SE COUNTIES TOWARDS DAYBREAK. LOW
STRATUS HAS BEEN SLOWER TO DEVELOP TONIGHT THAN THE PREVIOUS FEW
EVENINGS...BUT STILL EXPECT THEM TO MOVE IN WITHIN THE NEXT FEW
HOURS AND PERSIST FOR A FEW HOURS AFTER SUNRISE TODAY AND FRIDAY.
MODELS ARE CONSISTENT IN BUILDING AND INTENSIFYING THE UPPER
LEVEL RIDGE OVER THE SOUTHERN PLAINS TODAY AND FRIDAY AS AN
INVERTED TROUGH BREAKS OFF FROM THE PROGRESSIVE TROUGH AND
RETROGRADES UNDER THE RIDGE AS IT WEAKENS. THIS WILL HELP CAUSE A
0.2-0.3 INCH SURGE IN PWAT VALUES AND SLIGHTLY DEEPER CONVERGENCE
WITH THE SEA BREEZE THAN OCCURRED ON WEDNESDAY...ALLOWING FOR
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS IN THE COASTAL
PLAINS THAT WILL DISSIPATE AS THEY MOVE INTO THE I-35 CORRIDOR.
MODELS HAVE GENERALLY BACKED OFF FROM SHOWERS MOVING INTO THE HILL
COUNTRY EXCEPT FOR THE ECMWF AND A FEW HI-RES MODELS FOR FRIDAY.
LONG TERM (FRIDAY NIGHT THROUGH WEDNESDAY)...
THE UPPER LEVEL RIDGE WILL CONTINUE TO INTENSIFY THROUGH THE
WEEKEND AS THE RETROGRADING SHEAR AXIS DISSIPATES. THIS WILL LEAD
TO HOT AND GENERALLY DRY DAYS ASIDE FROM ISOLATED AFTERNOON
SHOWERS AND THUNDERSTORMS IN THE COASTAL PLAINS ON SATURDAY. HEAT
INDEX VALUES WILL RISE INTO THE 100-105 RANGE EVERYWHERE EXCEPT
THE COUNTRY FOR ALL OF LABOR DAY WEEKEND...WITH HIGH TEMPS IN THE
MID-TO-UPPER 90S EXCEPT FOR A FEW SPOTS IN THE RIO GRANDE PLAINS
THAT REACH THE CENTURY MARK. THE RIDGE GRADUALLY BEGINS TO WEAKEN
AND SLIDE TO THE WEST BY WEDNESDAY...WHICH MAY ALLOW A WEAK FRONT
TO MOVE INTO THE REGION LATE THURSDAY INTO FRIDAY JUST PAST THE
FORECAST PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 93 73 95 75 97 / 20 20 20 10 10
AUSTIN BERGSTROM INTL AIRPORT 92 72 94 73 96 / 20 20 20 10 10
NEW BRAUNFELS MUNI AIRPORT 93 73 96 74 97 / 20 20 20 10 10
BURNET MUNI AIRPORT 92 73 94 73 95 / 10 10 10 10 10
DEL RIO INTL AIRPORT 97 75 97 76 98 / 10 10 10 10 10
GEORGETOWN MUNI AIRPORT 92 73 94 75 95 / 10 10 10 10 10
HONDO MUNI AIRPORT 95 73 96 74 97 / 10 10 10 10 10
SAN MARCOS MUNI AIRPORT 92 73 94 75 96 / 20 20 20 10 10
LA GRANGE - FAYETTE REGIONAL 92 73 94 75 95 / 30 30 20 10 20
SAN ANTONIO INTL AIRPORT 94 74 95 76 96 / 20 20 10 10 10
STINSON MUNI AIRPORT 95 74 96 76 97 / 20 20 10 10 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...05
SYNOPTIC/GRIDS...ALLEN
PUBLIC SERVICE/DATA COLLECTION...30
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
419 AM CDT THU SEP 3 2015
.SHORT TERM /TODAY THROUGH FRIDAY/...THE LATEST WV IMAGERY SHOWS A
CIRCULATION JUST TO THE EAST OF BRO THIS MORNING. THIS VERIFIES THE
MODEL FORECAST OF THIS FEATURE`S SOUTHWARD MOVEMENT FROM YESTERDAY.
DRIER AIR IS TO THE WEST OF THE CIRCULATION...PRETTY MUCH COVERING
THE CWA. RADAR SHOWS ISOLATED CONVECTION OVER THE GULF TO THE EAST
THROUGH SOUTH OF BRO HOWEVER.
THE MARINE CONVECTION SHOULD NOT POSE MUCH OF A PROBLEM FOR THE CWA.
ON THE OTHER HAND...FORECAST PWAT WILL REMAIN NEAR TWO INCHES TODAY
AND FRIDAY...WITH THE HRRR SHOWING THE DEVELOPMENT OF A SEA BREEZE
FROM LATE MORNING TO MID AFTERNOON. MOSTLY CLEAR SKIES THIS MORNING
WILL GIVE EARLY ON DAYTIME HEATING A CHANCE TO CONTRIBUTE TO THE
ACTION...WITH OUTFLOW BOUNDARIES FROM COLLAPSING CELLS INTERSECTING
WITH EACH OTHER AND WITH THE SEA BREEZE. EFFICIENT TROPICAL...SUMMER
TIME RAIN MAKING CELLS MAY RESULT IN BRIEFLY HEAVIER DOWNPOURS...
WITH NUISANCE FLOODING POSSIBLE IN SOME AREAS.
THE UPPER CIRCULATION MAY BE ABLE TO REMAIN IDENTIFIABLE FOR ANOTHER
24 HRS AS IT DRIFTS FARTHER SOUTH AND WEST...BUT IT WILL EVENTUALLY
BE OVERSHADOWED BY RIDGING BUILDING OVER TEXAS. HOWEVER...THIS WILL
NOT TOTALLY SUPPRESS ANOTHER DAY OF UNORGANIZED CONVECTION AROUND
THE AREA FRIDAY...SOME OF WHICH WILL FEED OFF THE SEA BREEZE.
HAD NO REAL ISSUES CONTINUING WITH A MODEL CONSENSUS TO BUILD THE
SHORT TERM FORECAST. HIGH TEMPERATURES OUT WEST ARE DRIFTING UP A
BIT...TOPPING OUT NEAR THE CENTURY MARK FRIDAY AFTERNOON. POPS ARE
STILL PAINTED SLIGHTLY HIGHER OVER THE GULF THAN OVER LAND AREAS.
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...500 MB RIDGING WILL
REBUILD OVER TX AND NORTHERN MEXICO THIS WEEKEND INTO NEXT WEEK.
THIS WILL ALLOW A DRIER AND MORE SUBSIDENT ATMS TO BUILD OVER THE
AREA. THE BETTER MOISTURE VALUES WILL REMAIN CONFINED MAINLY TO
THE OFFSHORE WATERS AND NEAR THE COASTLINE AS A 500 MB CLOSED LOW
DEVELOPS OVER THE EASTERN AND CENTRAL GULF OF MEX. OVERALL THIS
TREND WILL TEND TO LIMIT THE CONV POTENTIAL THROUGHOUT THE
EXTENDED RANGE PERIOD. HOWEVER ISOLD MAINLY SEA BREEZE/DIURNALLY
DRIVEN CONV WILL REMAIN A THREAT THROUGH NEXT WED DUE TO THE
BETTER TROPICAL MOISTURE VALUES REMAINING POSITIONED JUST
OFFSHORE.
1000-500 MB THICKNESS VALUES WILL START TO INCREASE STEADLY
THROUGH DAY 7 ALLOWING THE HIGH TEMPS TO WARM SOMEWHAT. HOWEVER
RECENT RAINFALL OVER THE REGION WILL TEND TO LIMIT THE WARMUP DUE
TO THE HIGHER SOIL MOISTURE VALUES.
THE ECMWF AND GFS MEX MOS GUIDANCE ARE IN PRETTY GOOD AGREEMENT
FOR BOTH POPS AND TEMPS THROUGH DAY 7. 500 MB HEIGHTS FIELDS
COMPARISONS BETWEEN THE GFS AND THE ECMWF THROUGH NEXT FRIDAY
INDICATE PRETTY GOOD AGREEMENT IN THE PLACEMENT OF THE 500 MB
RIDGE AXIS OVER TX AND MEXICO AND THE BROAD TROFFING OVER THE GULF
OF MEX. RUN TO RUN CONSISTENCY WITH THE GFS MEX MOS TEMPS AND POPS
ARE PRETTY STABLE. SO OVERALL CONFIDENCE IN THE LONGER RANGE MODEL
GUIDANCE IS ABOVE AVERAGE AT THIS TIME. WILL GO WITH A GENERAL
50/50 MODEL BLEND FOR BOTH TEMPS AND POPS IN THE LONGER TERM
PERIOD.
&&
.MARINE...TODAY THROUGH FRIDAY...LITTLE CHANGE IN THE SHORT TERM AS
HIGH PRESSURE REMAINS IN PLACE OVER THE NORTHWEST GULF...WITH
SLIGHTLY LOWER PRESSURE TO THE SOUTH AND INLAND. THE RESULT WILL
BE LIGHT TO MODERATE SOUTH SOUTHEAST WINDS AND LOW TO MODERATE
SEAS. THERE WILL BE LITTLE RELIEF FROM ISOLATED TO SCATTERED
SHOWERS AND TSTMS IN THE SHORT TERM HOWEVER...WITH A MID LEVEL LOW
APPROXIMATELY OVERHEAD.
FRIDAY NIGHT THROUGH SUNDAY...BROAD SURFACE RIDGING OVER THE GULF
OF MEX AND THE TX COASTLINE WILL MAINTAIN LIGHT TO MODERATE S-SE
SURFACE WINDS FOR BOTH THE BAY AND GULF WATERS. THE GULF SWELLS
WILL REMAIN FAIRLY LOW DUE TO THE WEAKER SURFACE FLOW. NO SCA
CONDITIONS EXPECTED THROUGH SUNDAY. THE LATEST TROPICAL WEATHER
OUTLOOK FROM NHC DISCUSSES TS FRED IN THE ATLANTIC AND A TROPICAL
WAVE MOVING OFF OF THE WEST COAST OF AFRICA. THE GULF OF MEX
AND THE CARIB SEA REMAIN CLEAR OF TROPICAL ACTIVITY AT THIS TIME.
&&
.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL 90 79 91 80 / 30 20 20 20
BROWNSVILLE 90 78 91 77 / 40 20 20 10
HARLINGEN 92 77 94 77 / 40 20 20 10
MCALLEN 94 79 96 80 / 30 10 20 10
RIO GRANDE CITY 97 77 98 77 / 20 20 10 10
SOUTH PADRE ISLAND 86 80 86 81 / 30 30 30 20
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
SHORT TERM...55
LONG TERM...60
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1153 PM CDT WED SEP 2 2015
.DISCUSSION...
06Z TAF DISCUSSION IN AVIATION SECTION.
&&
.AVIATION...
WINDS HAVE DECOUPLED AND HAVE ALLOWED T/TD SPREADS TO NARROW AT
THE SURFACE. WITH A SCT/BKN HIGH CLOUDS SOME MVFR CIGS HAVE
DEVELOPED IN A FEW SPOTS INCLUDING KIAH/KHOU. THINK LOW STRATOCU
WILL LIKELY BE SCT/BKN THROUGH THE MORNING BUT WILL CARRY MVFR
CIGS IN THE TAFS. ALSO ADDED MENTION OF IFR CIGS FOR KCLL AND
MENTIONED MORE PESSIMISTIC CONDITIONS AT KCLL/KUTS/KCXO MAINLY FOR
FOG BUT COULD SEE AN IFR CIG AS WELL.
SHORT RANGE HRRR STILL SHOWING CONVECTION COMING INLAND AROUND
10-12Z PERHAPS SOONER. ANY SHRA SHOULD WEAKEN LATE MORNING ALONG
THE COAST BUT THEN POSSILBY REDEVELOP WITH DAY TIME HEATING
FARTHER INLAND. NOT SEEING AS MUCH DEEP MOISTURE IN MODEL GUIDANCE
AND UPPER LOW MAY BE WEAKENING...SO THINK ACTIVITY WILL BE MORE
ISO IN NATURE. SHOWER ACTIVITY SHOULD END IN THE EVENING WITH LOSS
OF DAY TIME HEATING AGAIN.
39
&&
.PREV DISCUSSION... /ISSUED /
DISCUSSION...
SHOWERS ENDED WITH SUNSET ACROSS THE CWA AND WILL LEAVE A FEW
HOURS OF TRANQUIL WEATHER. EXPECT TO SEE AN INCREASE DURING THE
EARLY MORNING HOURS ONCE AGAIN OVER THE WARM WATER AND NEAR THE
COAST...SPREADING OVER MORE OF THE COASTAL REGIONS THROUGH
SUNRISE. OTHERWISE...NO CHANGES NEEDED OVERNIGHT.
PREV DISCUSSION... /ISSUED /
DISCUSSION...
00Z TAF DISCUSSION IN AVIATION SECTION.
AVIATION...
WATER VAPOR IMAGERY SHOWS UPPER LOW OFF THE LOWER TX COAST WITH A
SHEAR AXIS EXTENDING ACROSS THE AREA FROM THE LOW. SHOWER ACTIVITY
SHOULD BE COMING TO AN END THE NEXT COUPLE OF HOURS BUT UNTIL THEN
WILL HAVE MINOR IMPACTS AT KIAH. EXPECT VFR CIGS FOR MOST AREAS.
KCLL/KUTS/KCXO MAY SEE SOME REDUCED VSBY AND LOW CIGS FOR THE
MORNING HOURS. NAM/GFS/LAMP GUIDANCE ALL GO WITH IFR/LIFR
CATEGORIES FOR THE MORNING. DO NOT THINK IT WILL BE THAT
PESSIMISTIC SO WILL MENTION MVFR CIGS IN A TEMPO GROUP FOR NOW.
EXPECT MORE OF THE SAME WITH SHOWERS DEVELOPING EARLY MORNING
ALONG THE COAST. SHRA MAY DEVELOP INLAND LIKE TODAY WITH MAYBE AN
ISO TSRA BUT LOW CONFIDENCE AT THIS POINT.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 73 92 75 94 76 / 20 20 10 20 10
HOUSTON (IAH) 73 91 75 93 76 / 30 30 20 30 10
GALVESTON (GLS) 77 88 79 90 79 / 50 50 30 40 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...48
AVIATION/MARINE...39
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1143 AM MDT THU SEP 3 2015
.UPDATE...
ISSUED AT 1006 AM MDT THU SEP 3 2015
SHOWERS ARE SPREADING NORTHWARD OUT OF NORTHEAST COLORADO AT THIS
TIME. SHOWER ACTIVITY WILL SLOWLY CONTINUE NORTHWARD THROUGH THIS
AFTERNOON AND EVENING IN ASSOCIATION WITH A WEAK SHORTWAVE MOVING
THROUGH SOUTHWEST FLOW ALOFT. A FEW EMBEDDED THUNDERSTORMS WILL
ALSO DEVELOP THIS AFTERNOON BUT THERE IS NO THREAT FOR SEVERE
THUNDERSTORMS.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 300 AM MDT THU SEP 3 2015
PRETTY QUIET WEATHER EARLY THIS MORNING ACROSS THE FORECAST AREA.
CURRENT WATER VAPOR LOOP SHOWS A RIDGE AXIS BUILDING OVER THE
GREAT PLAINS AS A BROAD UPPER LEVEL TROUGH SETTLES OVER THE
PACIFIC NORTHWEST...BRINGING MUCH NEEDED RAINFALL TO WASHINGTON
AND OREGON. THIS SYSTEM WILL EVENTUALLY IMPACT WYOMING THIS
WEEKEND. BEFORE THIS...CURRENT WATER VAPOR ALSO SHOWS A WELL
DEFINED SHORTWAVE DISTURBANCE ALOFT NEAR THE FOUR CORNERS REGION
WITH MID TO HIGH CLOUDS MOVING NORTHWARD WELL AHEAD OF IT. THIS
FEATURE WILL BE THE MAIN FORECAST CONCERN TODAY. A FEW MODELS
SHOW THIS FEATURE MOVING OVER SOUTHEAST WYOMING THIS AFTERNOON
PRODUCING SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS.
THUNDERSTORMS MAY PRODUCE SOME HEAVY RAINFALL AS SHORT RANGE
MODELS SUCH AS THE HRRR INDICATE REDEVELOPMENT AND TRAINING OVER
THE SAME AREA INTO LATE THIS EVENING. THIS IS DUE TO A POTENT
UPPER LEVEL JET AND GOOD 300MB DIFFLUENCE ALOFT. HOWEVER...NOT
ALL MODELS AGREE ON THE TIMING OF THIS FEATURE...WITH THE ECMWF
AND GEM 3 TO 6 HOURS BEHIND THE GFS. DUE TO PEAK HEATING AND
AVAILABLE INSTABILITY...THIS TIMING DIFFERENCE IS SIGNIFICANT. THE
NEW 06Z NAM IS IN GOOD AGREEMENT WITH THE GFS AND HRRR...SO
CONFIDENCE IS INCREASING THAT SEVERAL BANDS OF SHOWERS AND TSTORMS
WILL DEVELOP OVER THE ROCKY MOUNTAINS AND QUICKLY LIFT NORTHEAST
ACROSS THE I25 AND I80 CORRIDORS BY THIS AFTERNOON. INCREASED POP
ACROSS MOST OF THE AREA WITH THE EXCEPTION OF CARBON COUNTY.
INCREASED POP BETWEEN 30 TO 60 PERCENT FURTHER SOUTH AND
WEST...SINCE THERE IS STILL LOW CONFIDENCE IN SHOWER/TSTORM
COVERAGE NORTH OF THE PLATTE RIVER VALLEY DUE TO TIMING
DIFFERENCES.
FRIDAY WILL BE PRETTY SIMILAR TO THURSDAY WITH HIGH TEMPERATURES
IN THE 80S TO MID 90S AND ANOTHER GOOD CHANCE OF AFTERNOON SHOWERS
AND TSTORMS. IN FACT...CONDITIONS APPEAR MORE FAVORABLE IN THE
EVENING AS THE NAM...GFS...AND ECMWF SHOW QUITE A BIT OF UPPER
LEVEL DIFFLUENCE DUE TO JET DYNAMICS ALOFT. THIS DYNAMIC LIFT
PEAKS BETWEEN 00Z TO 06Z FRIDAY EVENING BEFORE LIFTING NORTHEAST.
INCREASED POP UP TO 45 PERCENT ACROSS THE HIGH PLAINS FRIDAY
EVENING.
THE UPPER LEVEL TROUGH OVER THE PACIFIC NORTHWEST WILL MOVE
TOWARDS THE FORECAST AREA ON SATURDAY. IT WILL BE SLIGHTLY COOLER
WITH HIGHS IN THE UPPER 70S TO UPPER 80S...BUT THE PRIMARY COLD
FRONT WILL NOT ENTER SOUTHEAST WYOMING UNTIL LATE SATURDAY NIGHT.
THIS MAIN STORM SYSTEM IS EXPECTED TO MOVE NORTHEAST AND REMAIN
NORTH OF THE FORECAST AREA. KEPT POP BETWEEN 10 TO 20 PERCENT WITH
THE HIGHEST CHANCE ACROSS THE MOUNTAINS...DUE TO SOME DRIER AIR
ALOFT AND A STABLE LAYER AROUND 500MB WHICH WILL INHIBIT WIDESPREAD
CONVECTION.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 230 AM MDT THU SEP 3 2015
THE UPPER LEVEL TROUGH WILL SWING NORTHEASTWARD ACROSS NORTHERN WY
ON SAT NIGHT AND SUN MORNING WITH AN ASSOCIATED FROPA. WINDS WILL
REALLY INCREASE BEHIND THE FRONT ON SUN MORNING AS THE MODELS SHOW
700MB WINDS OF 35-40 KTS OVER SOUTHEAST WY. THE GRADIENT DOES BEGIN
TO RELAX BY THE AFTN SO WINDS WILL COME DOWN SOME. WITH A VERY DRY
AIR MASS IN PLACE ON SUN AND MIN RH VALUES FALLING TO AROUND 15
PERCENT...THERE WILL LIKELY BE SOME FIRE WEATHER CONCERNS DESPITE
THE COOLER TEMPS. DRY WESTERLY MID LEVEL FLOW WILL REMAIN IN PLACE
THROUGH EARLY NEXT WEEK WITH PW VALUES OF ONLY 0.25-0.5 INCHES AND
NO HINT OF ANY MONSOONAL MOISTURE INTRUSION. TEMPS WILL BE AROUND
NORMAL FOR EARLY SEP WITH COOLER NIGHTS THAN WE HAVE SEEN RECENTLY.
THE MODEL DIFFERENCES BETWEEN THE GFS AND ECMWF REALLY BEGIN TO SHOW
UP BY TUESDAY AS THE GFS SHOWS A STRONGER SHORTWAVE MOVING ACROSS WY.
REGARDLESS OF THE SOLUTION...A DRY FCST WILL PREVAIL WITH LIMITED
MOISTURE AND DYNAMICS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1138 AM MDT THU SEP 3 2015
VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD. WEST TO
SOUTHWEST SURFACE WINDS WILL BE BREEZY AT TIMES ACROSS SOUTHEAST
WY WITH GUSTS TO 25 KT POSSIBLE THIS AFTERNOON. SCATTERED SHOWERS
AND ISOLATED TSTORMS OVER NE CO WILL SPREAD NORTHEAST INTO
SOUTHEAST WY AND WESTERN NE THROUGH THE EVENING. GUSTY WINDS AND
BRIEF MVFR VISIBILITY IN MODERATE TO HEAVY RAIN WILL BE POSSIBLE.
&&
.FIRE WEATHER...
ISSUED AT 230 AM MDT THU SEP 3 2015
IT WILL BE PRETTY DRY INITIALLY THIS AFTERNOON OVER EAST CENTRAL
WYOMING BEFORE SOME SUBTROPICAL MOISTURE MOVES INTO THE
AREA...AHEAD OF AN UPPER LEVEL DISTURBANCE. ALTHOUGH FIRE WEATHER
CONCERNS ARE LOW TODAY...WILL HAVE TO MONITOR WIND SPEEDS ACROSS
ZONE 301 AND 302. FOR NOW...WINDS ARE EXPECTED TO BE BELOW 20 MPH
AT THIS TIME. MINIMAL FIRE WEATHER CONCERNS ARE ANTICIPATED FRIDAY
AND SATURDAY AS THUNDERSTORM COVERAGE WILL INCREASE AND RELATIVE
HUMIDITIES WILL TREND HIGHER...MINIMUM DAYTIME RELATIVE HUMIDITIES
WILL BE BETWEEN 20 TO 30 PERCENT BY SATURDAY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...SML
SHORT TERM...TJT
LONG TERM...ZF
AVIATION...MAJ
FIRE WEATHER...TJT
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1017 AM MDT THU SEP 3 2015
.UPDATE...
ISSUED AT 1006 AM MDT THU SEP 3 2015
SHOWERS ARE SPREADING NORTHWARD OUT OF NORTHEAST COLORADO AT THIS
TIME. SHOWER ACTIVITY WILL SLOWLY CONTINUE NORTHWARD THROUGH THIS
AFTERNOON AND EVENING IN ASSOCIATION WITH A WEAK SHORTWAVE MOVING
THROUGH SOUTHWEST FLOW ALOFT. A FEW EMBEDDED THUNDERSTORMS WILL
ALSO DEVELOP THIS AFTERNOON BUT THERE IS NO THREAT FOR SEVERE
THUNDERSTORMS.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 300 AM MDT THU SEP 3 2015
PRETTY QUIET WEATHER EARLY THIS MORNING ACROSS THE FORECAST AREA.
CURRENT WATER VAPOR LOOP SHOWS A RIDGE AXIS BUILDING OVER THE
GREAT PLAINS AS A BROAD UPPER LEVEL TROUGH SETTLES OVER THE
PACIFIC NORTHWEST...BRINGING MUCH NEEDED RAINFALL TO WASHINGTON
AND OREGON. THIS SYSTEM WILL EVENTUALLY IMPACT WYOMING THIS
WEEKEND. BEFORE THIS...CURRENT WATER VAPOR ALSO SHOWS A WELL
DEFINED SHORTWAVE DISTURBANCE ALOFT NEAR THE FOUR CORNERS REGION
WITH MID TO HIGH CLOUDS MOVING NORTHWARD WELL AHEAD OF IT. THIS
FEATURE WILL BE THE MAIN FORECAST CONCERN TODAY. A FEW MODELS
SHOW THIS FEATURE MOVING OVER SOUTHEAST WYOMING THIS AFTERNOON
PRODUCING SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS.
THUNDERSTORMS MAY PRODUCE SOME HEAVY RAINFALL AS SHORT RANGE
MODELS SUCH AS THE HRRR INDICATE REDEVELOPMENT AND TRAINING OVER
THE SAME AREA INTO LATE THIS EVENING. THIS IS DUE TO A POTENT
UPPER LEVEL JET AND GOOD 300MB DIFLUENCE ALOFT. HOWEVER...NOT ALL
MODELS AGREE ON THE TIMING OF THIS FEATURE...WITH THE ECMWF AND
GEM 3 TO 6 HOURS BEHIND THE GFS. DUE TO PEAK HEATING AND AVAILABLE
INSTABILITY...THIS TIMING DIFFERENCE IS SIGNIFICANT. THE NEW 06Z
NAM IS IN GOOD AGREEMENT WITH THE GFS AND HRRR...SO CONFIDENCE IS
INCREASING THAT SEVERAL BANDS OF SHOWERS AND TSTORMS WILL DEVELOP
OVER THE ROCKY MOUNTAINS AND QUICKLY LIFT NORTHEAST ACROSS THE I25
AND I80 CORRIDORS BY THIS AFTERNOON. INCREASED POP ACROSS MOST OF
THE AREA WITH THE EXCEPTION OF CARBON COUNTY. INCREASED POP
BETWEEN 30 TO 60 PERCENT FURTHER SOUTH AND WEST...SINCE THERE IS
STILL LOW CONFIDENCE IN SHOWER/TSTORM COVERAGE NORTH OF THE PLATTE
RIVER VALLEY DUE TO TIMING DIFFERENCES.
FRIDAY WILL BE PRETTY SIMILAR TO THURSDAY WITH HIGH TEMPERATURES
IN THE 80S TO MID 90S AND ANOTHER GOOD CHANCE OF AFTERNOON SHOWERS
AND TSTORMS. IN FACT...CONDITIONS APPEAR MORE FAVORABLE IN THE
EVENING AS THE NAM...GFS...AND ECMWF SHOW QUITE A BIT OF UPPER
LEVEL DIFLUENCE DUE TO JET DYNAMICS ALOFT. THIS DYNAMIC LIFT PEAKS
BETWEEN 00Z TO 06Z FRIDAY EVENING BEFORE LIFTING NORTHEAST.
INCREASED POP UP TO 45 PERCENT ACROSS THE HIGH PLAINS FRIDAY
EVENING.
THE UPPER LEVEL TROUGH OVER THE PACIFIC NORTHWEST WILL MOVE
TOWARDS THE FORECAST AREA ON SATURDAY. IT WILL BE SLIGHTLY COOLER
WITH HIGHS IN THE UPPER 70S TO UPPER 80S...BUT THE PRIMARY COLD
FRONT WILL NOT ENTER SOUTHEAST WYOMING UNTIL LATE SATURDAY NIGHT.
THIS MAIN STORM SYSTEM IS EXPECTED TO MOVE NORTHEAST AND REMAIN
NORTH OF THE FORECAST AREA. KEPT POP BETWEEN 10 TO 20 PERCENT WITH
THE HIGHEST CHANCE ACROSS THE MOUNTAINS...DUE TO SOME DRIER AIR
ALOFT AND A STABLE LAYER AROUND 500MB WHICH WILL INHIBIT WIDESPREAD
CONVECTION.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 230 AM MDT THU SEP 3 2015
THE UPPER LEVEL TROUGH WILL SWING NORTHEASTWARD ACROSS NORTHERN WY
ON SAT NIGHT AND SUN MORNING WITH AN ASSOCIATED FROPA. WINDS WILL
REALLY INCREASE BEHIND THE FRONT ON SUN MORNING AS THE MODELS SHOW
700MB WINDS OF 35-40 KTS OVER SOUTHEAST WY. THE GRADIENT DOES BEGIN
TO RELAX BY THE AFTN SO WINDS WILL COME DOWN SOME. WITH A VERY DRY
AIR MASS IN PLACE ON SUN AND MIN RH VALUES FALLING TO AROUND 15
PERCENT...THERE WILL LIKELY BE SOME FIRE WEATHER CONCERNS DESPITE
THE COOLER TEMPS. DRY WESTERLY MID LEVEL FLOW WILL REMAIN IN PLACE
THROUGH EARLY NEXT WEEK WITH PW VALUES OF ONLY 0.25-0.5 INCHES AND
NO HINT OF ANY MONSOONAL MOISTURE INTRUSION. TEMPS WILL BE AROUND
NORMAL FOR EARLY SEP WITH COOLER NIGHTS THAN WE HAVE SEEN RECENTLY.
THE MODEL DIFFERENCES BETWEEN THE GFS AND ECMWF REALLY BEGIN TO SHOW
UP BY TUESDAY AS THE GFS SHOWS A STRONGER SHORTWAVE MOVING ACROSS WY.
REGARDLESS OF THE SOLUTION...A DRY FCST WILL PREVAIL WITH LIMITED
MOISTURE AND DYNAMICS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 532 AM MDT THU SEP 3 2015
VFR CONDITIONS THROUGH THE TAF PERIOD. WINDS WILL MOSTLY REMAIN
BELOW 15 KTS...EXCEPT AT RWL WHERE GUSTS TO 20 KTS WILL BE
POSSIBLE DURING THE AFTERNOON. ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS WILL DEVELOP AFTER 20Z ACROSS SOUTHEAST WY AND THEN
MOVE EASTWARD INTO THE NEBRASKA PANHANDLE THROUGH THE EVENING.
GUSTY AND ERRATIC WINDS ALONG WITH BRIEF HEAVY RAIN WILL BE
POSSIBLE WITH THE STORMS.
&&
.FIRE WEATHER...
ISSUED AT 230 AM MDT THU SEP 3 2015
IT WILL BE PRETTY DRY INITIALLY THIS AFTERNOON OVER EAST CENTRAL
WYOMING BEFORE SOME SUBTROPICAL MOISTURE MOVES INTO THE
AREA...AHEAD OF AN UPPER LEVEL DISTURBANCE. ALTHOUGH FIRE WEATHER
CONCERNS ARE LOW TODAY...WILL HAVE TO MONITOR WIND SPEEDS ACROSS
ZONE 301 AND 302. FOR NOW...WINDS ARE EXPECTED TO BE BELOW 20 MPH
AT THIS TIME. MINIMAL FIRE WEATHER CONCERNS ARE ANTICIPATED FRIDAY
AND SATURDAY AS THUNDERSTORM COVERAGE WILL INCREASE AND RELATIVE
HUMIDITIES WILL TREND HIGHER...MINIMUM DAYTIME RELATIVE HUMIDITIES
WILL BE BETWEEN 20 TO 30 PERCENT BY SATURDAY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...SML
SHORT TERM...TJT
LONG TERM...ZF
AVIATION...ZF
FIRE WEATHER...TJT
AREA FORECAST DISCUSSION...CORRECTED SHORT TERM
NWS CHEYENNE WY
535 AM MDT THU SEP 3 2015
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 300 AM MDT THU SEP 3 2015
PRETTY QUIET WEATHER EARLY THIS MORNING ACROSS THE FORECAST AREA.
CURRENT WATER VAPOR LOOP SHOWS A RIDGE AXIS BUILDING OVER THE
GREAT PLAINS AS A BROAD UPPER LEVEL TROUGH SETTLES OVER THE
PACIFIC NORTHWEST...BRINGING MUCH NEEDED RAINFALL TO WASHINGTON
AND OREGON. THIS SYSTEM WILL EVENTUALLY IMPACT WYOMING THIS
WEEKEND. BEFORE THIS...CURRENT WATER VAPOR ALSO SHOWS A WELL
DEFINED SHORTWAVE DISTURBANCE ALOFT NEAR THE FOUR CORNERS REGION
WITH MID TO HIGH CLOUDS MOVING NORTHWARD WELL AHEAD OF IT. THIS
FEATURE WILL BE THE MAIN FORECAST CONCERN TODAY. A FEW MODELS
SHOW THIS FEATURE MOVING OVER SOUTHEAST WYOMING THIS AFTERNOON
PRODUCING SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS.
THUNDERSTORMS MAY PRODUCE SOME HEAVY RAINFALL AS SHORT RANGE
MODELS SUCH AS THE HRRR INDICATE REDEVELOPMENT AND TRAINING OVER
THE SAME AREA INTO LATE THIS EVENING. THIS IS DUE TO A POTENT
UPPER LEVEL JET AND GOOD 300MB DIFLUENCE ALOFT. HOWEVER...NOT ALL
MODELS AGREE ON THE TIMING OF THIS FEATURE...WITH THE ECMWF AND
GEM 3 TO 6 HOURS BEHIND THE GFS. DUE TO PEAK HEATING AND AVAILABLE
INSTABILITY...THIS TIMING DIFFERENCE IS SIGNIFICANT. THE NEW 06Z
NAM IS IN GOOD AGREEMENT WITH THE GFS AND HRRR...SO CONFIDENCE IS
INCREASING THAT SEVERAL BANDS OF SHOWERS AND TSTORMS WILL DEVELOP
OVER THE ROCKY MOUNTAINS AND QUICKLY LIFT NORTHEAST ACROSS THE I25
AND I80 CORRIDORS BY THIS AFTERNOON. INCREASED POP ACROSS MOST OF
THE AREA WITH THE EXCEPTION OF CARBON COUNTY. INCREASED POP
BETWEEN 30 TO 60 PERCENT FURTHER SOUTH AND WEST...SINCE THERE IS
STILL LOW CONFIDENCE IN SHOWER/TSTORM COVERAGE NORTH OF THE PLATTE
RIVER VALLEY DUE TO TIMING DIFFERENCES.
FRIDAY WILL BE PRETTY SIMILAR TO THURSDAY WITH HIGH TEMPERATURES
IN THE 80S TO MID 90S AND ANOTHER GOOD CHANCE OF AFTERNOON SHOWERS
AND TSTORMS. IN FACT...CONDITIONS APPEAR MORE FAVORABLE IN THE
EVENING AS THE NAM...GFS...AND ECMWF SHOW QUITE A BIT OF UPPER
LEVEL DIFLUENCE DUE TO JET DYNAMICS ALOFT. THIS DYNAMIC LIFT PEAKS
BETWEEN 00Z TO 06Z FRIDAY EVENING BEFORE LIFTING NORTHEAST.
INCREASED POP UP TO 45 PERCENT ACROSS THE HIGH PLAINS FRIDAY
EVENING.
THE UPPER LEVEL TROUGH OVER THE PACIFIC NORTHWEST WILL MOVE
TOWARDS THE FORECAST AREA ON SATURDAY. IT WILL BE SLIGHTLY COOLER
WITH HIGHS IN THE UPPER 70S TO UPPER 80S...BUT THE PRIMARY COLD
FRONT WILL NOT ENTER SOUTHEAST WYOMING UNTIL LATE SATURDAY NIGHT.
THIS MAIN STORM SYSTEM IS EXPECTED TO MOVE NORTHEAST AND REMAIN
NORTH OF THE FORECAST AREA. KEPT POP BETWEEN 10 TO 20 PERCENT WITH
THE HIGHEST CHANCE ACROSS THE MOUNTAINS...DUE TO SOME DRIER AIR
ALOFT AND A STABLE LAYER AROUND 500MB WHICH WILL INHIBIT WIDESPREAD
CONVECTION.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 230 AM MDT THU SEP 3 2015
THE UPPER LEVEL TROUGH WILL SWING NORTHEASTWARD ACROSS NORTHERN WY
ON SAT NIGHT AND SUN MORNING WITH AN ASSOCIATED FROPA. WINDS WILL
REALLY INCREASE BEHIND THE FRONT ON SUN MORNING AS THE MODELS SHOW
700MB WINDS OF 35-40 KTS OVER SOUTHEAST WY. THE GRADIENT DOES BEGIN
TO RELAX BY THE AFTN SO WINDS WILL COME DOWN SOME. WITH A VERY DRY
AIR MASS IN PLACE ON SUN AND MIN RH VALUES FALLING TO AROUND 15
PERCENT...THERE WILL LIKELY BE SOME FIRE WEATHER CONCERNS DESPITE
THE COOLER TEMPS. DRY WESTERLY MID LEVEL FLOW WILL REMAIN IN PLACE
THROUGH EARLY NEXT WEEK WITH PW VALUES OF ONLY 0.25-0.5 INCHES AND
NO HINT OF ANY MONSOONAL MOISTURE INTRUSION. TEMPS WILL BE AROUND
NORMAL FOR EARLY SEP WITH COOLER NIGHTS THAN WE HAVE SEEN RECENTLY.
THE MODEL DIFFERENCES BETWEEN THE GFS AND ECMWF REALLY BEGIN TO SHOW
UP BY TUESDAY AS THE GFS SHOWS A STRONGER SHORTWAVE MOVING ACROSS WY.
REGARDLESS OF THE SOLUTION...A DRY FCST WILL PREVAIL WITH LIMITED
MOISTURE AND DYNAMICS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 532 AM MDT THU SEP 3 2015
VFR CONDITIONS THROUGH THE TAF PERIOD. WINDS WILL MOSTLY REMAIN
BELOW 15 KTS...EXCEPT AT RWL WHERE GUSTS TO 20 KTS WILL BE
POSSIBLE DURING THE AFTERNOON. ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS WILL DEVELOP AFTER 20Z ACROSS SOUTHEAST WY AND THEN
MOVE EASTWARD INTO THE NEBRASKA PANHANDLE THROUGH THE EVENING.
GUSTY AND ERRATIC WINDS ALONG WITH BRIEF HEAVY RAIN WILL BE
POSSIBLE WITH THE STORMS.
&&
.FIRE WEATHER...
ISSUED AT 230 AM MDT THU SEP 3 2015
IT WILL BE PRETTY DRY INITIALLY THIS AFTERNOON OVER EAST CENTRAL
WYOMING BEFORE SOME SUBTROPICAL MOISTURE MOVES INTO THE
AREA...AHEAD OF AN UPPER LEVEL DISTURBANCE. ALTHOUGH FIRE WEATHER
CONCERNS ARE LOW TODAY...WILL HAVE TO MONITOR WIND SPEEDS ACROSS
ZONE 301 AND 302. FOR NOW...WINDS ARE EXPECTED TO BE BELOW 20 MPH
AT THIS TIME. MINIMAL FIRE WEATHER CONCERNS ARE ANTICIPATED FRIDAY
AND SATURDAY AS THUNDERSTORM COVERAGE WILL INCREASE AND RELATIVE
HUMIDITIES WILL TREND HIGHER...MINIMUM DAYTIME RELATIVE HUMIDITIES
WILL BE BETWEEN 20 TO 30 PERCENT BY SATURDAY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...TJT
LONG TERM...ZF
AVIATION...ZF
FIRE WEATHER...TJT
AREA FORECAST DISCUSSION...UPDATED
NWS CHEYENNE WY
334 AM MDT THU SEP 3 2015
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 300 AM MDT THU SEP 3 2015
PRETTY QUIET WEATHER EARLY THIS MORNING ACROSS THE FORECAST AREA.
CURRENT WATER VAPOR LOOP SHOWS A RIDGE AXIS BUILDING OVER THE
GREAT PLAINS AS A BROAD UPPER LEVEL TROUGH SETTLES OVER THE
PACIFIC NORTHWEST...BRINGING MUCH NEEDED RAINFALL TO WASHINGTON
AND OREGON. THIS SYSTEM WILL EVENTUALLY IMPACT WYOMING THIS
WEEKEND. BEFORE THIS...CURRENT WATER VAPOR ALSO SHOWS A WELL
DEFINED SHORTWAVE DISTURBANCE ALOFT NEAR THE FOUR CORNERS REGION
WITH MID TO HIGH CLOUDS MOVING NORTHWARD WELL AHEAD OF IT. THIS
FEATURE WILL BE THE MAIN FORECAST CONCERN TODAY. A FEW MODELS
SHOW THIS FEATURE MOVING OVER SOUTHEAST WYOMING THIS AFTERNOON
PRODUCING SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS.
THUNDERSTORMS MAY PRODUCE SOME HEAVY RAINFALL AS SHORT RANGE
MODELS SUCH AS THE HRRR INDICATE REDEVELOPMENT AND TRAINING OVER
THE SAME AREA INTO LATE THIS EVENING. THIS IS DUE TO A POTENT
UPPER LEVEL JET AND GOOD 300MB DIFLUENCE ALOFT. HOWEVER...NOT ALL
MODELS AGREE ON THE TIMING OF THIS FEATURE...WITH THE ECMWF AND
GEM 3 TO 6 HOURS BEHIND THE GFS. DUE TO PEAK HEATING AND AVAILABLE
INSTABILITY...THIS TIMING DIFFERENCE IS SIGNIFICANT. THE NEW 06Z
NAM IS IN GOOD AGREEMENT WITH THE GFS AND HRRR...SO CONFIDENCE IS
INCREASING THAT SEVERAL BANDS OF SHOWERS AND TSTORMS WILL DEVELOP
OVER THE ROCKY MOUNTAINS AND QUICKLY LIFT NORTHEAST ACROSS THE I25
AND I80 CORRIDORS BY THIS AFTERNOON. INCREASED POP ACROSS MOST OF
THE AREA WITH THE EXCEPTION OF CARBON COUNTY. INCREASED POP
BETWEEN 30 TO 60 PERCENT FURTHER SOUTH AND WEST...SINCE THERE IS
STILL LOW CONFIDENCE IN SHOWER/TSTORM COVERAGE NORTH OF THE PLATTE
RIVER VALLEY DUE TO TIMING DIFFERENCES.
FRIDAY WILL BE PRETTY SIMILAR TO THURSDAY WITH HIGH TEMPERATURES
IN THE 80S TO MID 90S AND ANOTHER GOOD CHANCE OF AFTERNOON SHOWERS
AND TSTORMS. IN FACT...CONDITIONS APPEAR MORE FAVORABLE IN THE
EVENING AS THE NAM...GFS...AND ECMWF SHOW QUITE A BIT OF UPPER
LEVEL DIFLUENCE DUE TO JET DYNAMICS ALOFT. THIS DYNAMIC LIFT PEAKS
BETWEEN 00Z TO 06Z FRIDAY EVENING BEFORE LIFTING NORTHEAST.
INCREASED POP UP TO 45 PERCENT ACROSS THE HIGH PLAINS FRIDAY
EVENING.
THE UPPER LEVEL TROUGH OVER THE PACIFIC NORTHWEST WILL MOVE
TOWARDS THE FORECAST AREA ON SATURDAY. IT WILL BE SLIGHTLY COOLER
WITH HIGHS IN THE UPPER 80S TO UPPER 80S...BUT THE PRIMARY COLD
FRONT WILL NOT ENTER SOUTHEAST WYOMING UNTIL LATE SATURDAY NIGHT.
THIS MAIN STORM SYSTEM IS EXPECTED TO MOVE NORTHEAST AND REMAIN
NORTH OF THE FORECAST AREA. KEPT POP BETWEEN 10 TO 20 PERCENT
WITH THE HIGHEST CHANCE ACROSS THE MOUNTAINS...DUE TO SOME DRIER
AIR ALOFT AND A STABLE LAYER AROUND 500MB WHICH WILL INHIBIT
WIDESPREAD CONVECTION.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 230 AM MDT THU SEP 3 2015
THE UPPER LEVEL TROUGH WILL SWING NORTHEASTWARD ACROSS NORTHERN WY
ON SAT NIGHT AND SUN MORNING WITH AN ASSOCIATED FROPA. WINDS WILL
REALLY INCREASE BEHIND THE FRONT ON SUN MORNING AS THE MODELS SHOW
700MB WINDS OF 35-40 KTS OVER SOUTHEAST WY. THE GRADIENT DOES BEGIN
TO RELAX BY THE AFTN SO WINDS WILL COME DOWN SOME. WITH A VERY DRY
AIRMASS IN PLACE ON SUN AND MIN RH VALUES FALLING TO AROUND 15
PERCENT...THERE WILL LIKELY BE SOME FIRE WEATHER CONCERNS DESPITE
THE COOLER TEMPS. DRY WESTERLY MIDLVL FLOW WILL REMAIN IN PLACE
THROUGH EARLY NEXT WEEK WITH PW VALUES OF ONLY 0.25-0.5 INCHES AND
NO HINT OF ANY MONSOONAL MOISTURE INTRUSION. TEMPS WILL BE AROUND
NORMAL FOR EARLY SEP WITH COOLER NIGHTS THAN WE HAVE SEEN RECENTLY.
THE MODEL DIFFERENCES BETWEEN THE GFS AND ECMWF REALLY BEGIN TO SHOW
UP BY TUES AS THE GFS SHOWS A STRONGER SHORTWAVE MOVING ACROSS WY.
REGARDLESS OF THE SOLN...A DRY FCST WILL PREVAIL WITH LIMITED
MOISTURE AND DYNAMICS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1157 PM MDT WED SEP 2 2015
VFR CONDITIONS THROUGH THE TAF PERIOD. WINDS WILL REMAIN LIGHT
THROUGH THURSDAY MORNING. ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS WILL DEVELOP AFTER 20Z THURS ACROSS MUCH OF THE
REGION. GUSTY AND ERRATIC WINDS ALONG WITH BRIEF HEAVY RAIN WILL
BE POSSIBLE WITH THE STORMS.
&&
.FIRE WEATHER...
ISSUED AT 230 AM MDT THU SEP 3 2015
IT WILL BE PRETTY DRY INITIALLY THIS AFTERNOON OVER EAST CENTRAL
WYOMING BEFORE SOME SUBTROPICAL MOISTURE MOVES INTO THE
AREA...AHEAD OF AN UPPER LEVEL DISTURBANCE. ALTHOUGH FIRE WEATHER
CONCERNS ARE LOW TODAY...WILL HAVE TO MONITOR WIND SPEEDS ACROSS
ZONE 301 AND 302. FOR NOW...WINDS ARE EXPECTED TO BE BELOW 20 MPH
AT THIS TIME. MINIMAL FIRE WEATHER CONCERNS ARE ANTICIPATED FRIDAY
AND SATURDAY AS THUNDERSTORM COVERAGE WILL INCREASE AND RELATIVE
HUMIDITIES WILL TREND HIGHER...MINIMUM DAYTIME RELATIVE HUMIDITIES
WILL BE BETWEEN 20 TO 30 PERCENT BY SATURDAY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...TJT
LONG TERM...ZF
AVIATION...ZF
FIRE WEATHER...TJT
AREA FORECAST DISCUSSION
NWS TUCSON AZ
919 PM MST FRI SEP 4 2015
.SYNOPSIS...A MOIST ATMOSPHERE WILL REMAIN IN PLACE THROUGH THIS
WEEKEND...WITH ISOLATED TO SCATTERED MAINLY AFTERNOON AND EVENING
SHOWERS AND THUNDERSTORMS THROUGH SUNDAY. A GRADUALLY REDUCTION IN
AREAL COVERAGE OF STORMS WILL OCCUR EARLY NEXT WEEK. BELOW NORMAL
DAYTIME TEMPERATURES WILL PREVAIL THROUGH THIS WEEKEND...WITH HIGH
TEMPERATURES RETURNING CLOSE TO SEASONAL NORMALS BY THE MIDDLE OF
NEXT WEEK.
&&
.DISCUSSION...IT FELT LIKE AN OCTOBER DAY OUT THERE TODAY...WITH
TUCSON RECORDING ITS COOLEST HIGH TEMPERATURE SINCE WAY BACK ON MAY
24TH (83 DEGREES F). CURRENTLY...KEMX RADAR SHOWS JUST LIGHT SHOWERS
CONTINUING MAINLY SOUTH AND EAST OF TUCSON WITH TRENDS TOWARDS
SLOWLY DECREASING COVERAGE. IR SATELLITE LOOPS SHOW MOSTLY CLOUDY TO
CLOUDY SKIES AREA-WIDE...WHICH SHOULD PERSIST THROUGH THE OVERNIGHT
HOURS HELPING TO TEMPER OUR LOWS SOMEWHAT. STILL...ANOTHER COOL
MORNING IS ON TAP TOMORROW WITH BELOW-NORMAL LOWS.
BASED ON SATELLITE AND RADAR TRENDS...AS WELL AS A GLANCE AT THE
RECENT RAP...UNIV OF AZ. WRF-NAM...AND NAM12...DROPPED POPS OUT WEST
BUT WILL KEEP A MENTION OF AT LEAST ISOLATED SHOWERS THROUGH THE
OVERNIGHT PERIOD BASICALLY FROM TUCSON AND POINTS SOUTH AND EAST
WHERE SOME SUBTLE RIPPLES IN THE FLOW MAY OFFER ENOUGH DYNAMIC
SUPPORT TO CONTINUE LIGHT PRECIP THERE INTO THE MORNING HOURS.
TOMORROW MAY ONCE AGAIN BE FAIRLY SUBDUED WEATHER-WISE AS POOR MID-
LEVEL LAPSE RATES AND CLOUD COVER LIMITS OUR OVERALL INSTABILITY.
THAT SAID...THE 05/02Z RAP AND NAM12 INDICATE WE MAY GET SOME
ASSISTANCE FROM WEAK MID-LEVEL FEATURES...AND THE UPPER-LEVEL FLOW
MAY BECOME A TOUCH MORE DIFFLUENT OVERALL.
&&
.AVIATION...VALID THRU 06/06Z.
ISOLATED TO SCATTERED -SHRA WILL PERSIST OVERNIGHT BUT CONTINUE TO
GRADUALLY DECREASE IN COVERAGE SOUTH AND EAST OF KTUS. EXPECT BKN-
OVC CLOUDS AT 9-12 KFT AGL. ISOLATED TO PERHAPS SCATTERED
-SHRA/-TSRA DEVELOPING TOMORROW AFTER ABOUT 05/20Z. BRIEF MVFR
CONDITIONS POSSIBLE IN AND AROUND THE STRONGEST STORMS. OUTSIDE OF
THUNDERSTORM WIND GUSTS...SURFACE WINDS WILL GENERALLY BE LESS THAN
10 KTS AND MAINTAIN A MORE SOUTHERLY COMPONENT THAN USUAL DURING
THE AFTERNOON. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...MOIST CONDITIONS WILL LINGER THROUGH THE NEXT 24
HOURS OVER EASTERN AREAS WITH HIGH TEMPERATURES BELOW NORMAL AND
GOOD RH RECOVERY AREA WIDE. WINDS WILL FAVOR A SOUTHERLY
DIRECTION...BUT WILL BE LIGHT ENOUGH TO SEE STRONG TERRAIN
INFLUENCES. AFTERNOON SHOWERS AND ISOLATED THUNDERSTORMS WILL REMAIN
IN THE FORECAST THROUGH THE HOLIDAY WEEKEND.
&&
.PREV DISCUSSION...A FEW LINGERING LIGHT SHOWERS ARE POSSIBLE
OVERNIGHT. SCATTERED SHOWERS AND THUNDERSTORMS SHOULD FIRE UP AGAIN
ON SATURDAY AFTERNOON AS MOISTURE CONTINUES TO HANG AROUND.
THEREAFTER...THE TROUGH CURRENTLY LOCATED IN THE PAC NW WILL SWING
EWD THRU THE NRN ROCKIES. SWLY FLOW WILL CONTINUE OVER THE AREA
THROUGH SUNDAY...AND IN CONJUNCTION WITH A BREAK BETWEEN TROPICAL
SYSTEMS...WILL USHER IN SOME DRIER AIR. THIS SLIGHT DOWNTURN IN
ACTIVITY WILL BE SHORT LIVED AS THE NEXT TROPICAL SYSTEM BEGINS TO
PUSH MOISTURE NORTHWARD INTO SE AZ EARLY NEXT WEEK. BY MIDWEEK...THE
UPPER LEVEL JET IS FAIRLY ZONAL FOR A SHORT TIME AND LOCATED NEAR
THE CANADIAN BORDER...ALLOWING FOR WESTERLY FLOW ACROSS THE DESERT
SW. THE TIMING AND LOCATION FOR THE BEST PRECIP CHANCES WILL BE
HIGHLY DEPENDENT ON THE TRACK OF THIS NEXT TROPICAL SYSTEM. THAT
SAID...ONLY MINOR CHANGES WERE MADE TO INHERITED POPS THROUGH THE
MIDDLE OF NEXT WEEK.
LATE NEXT WEEK...BOTH THE 04/12Z GFS/ECMWF INDICATED NWLY FLOW
RETURNING TO THE AREA...WITH RIDGING IN THE WEST AND A TROF DIGGING
THROUGH THE GREAT LAKES REGION. THIS SHOULD HELP TO DRY THINGS OUT
WITH THE CAVEAT BEING ANY LINGERING TROPICAL MOISTURE. FOR
NOW...HAVE MAINTAINED JUST SLIGHT CHANCES FOR PRECIP FOR SRN/ERN
ZONES.
TEMPERATURES THIS WEEKEND WILL REMAIN BELOW NORMAL...FOLLOWED BY A
GRADUAL WARMING TREND TO NEAR-NORMAL LEVELS BY THE MIDDLE OF NEXT
WEEK.
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
DISCUSSION...CARLAW
PREV DISCUSSION...FRENCH/CANTIN
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1114 PM MDT FRI SEP 4 2015
.UPDATE...
ISSUED AT 1059 PM MDT FRI SEP 4 2015
A DISTURBANCE PRODUCING A THICK LINE OF SHOWERS AND THUNDERSTORMS
ALONG THE CO AND UT BORDER WILL MOVE THROUGH SW AND CENTRAL CO
BETWEEN 11 PM AND ABOUT 3 AM. HAVE INCREASED POPS...CLOUDS...AND
QPF TO SHOW THIS LINE PROGRESSING ACROSS THE SOUTHERN TWO THIRDS
OF THE CWA IN THE NEXT SEVERAL HOURS.
&&
.SHORT TERM...(TONIGHT THROUGH SATURDAY NIGHT)
ISSUED AT 344 PM MDT FRI SEP 4 2015
AN UNSETTLED MOIST SW FLOW CONTINUES THROUGH THESE PERIODS.
THIS AFTERNOON-OVERNIGHT...THE MORNING MODEL RUNS CONTINUE TO NOT
RESOLVE ORGANIZED FORCING. JET SUPPORT REMAINS STRETCHED SW-NE
ACROSS THE FORECAST AREA AND PRECIP WATER VALUES ARE NEAR ONE INCH
IN THE LOWER ELEVATIONS. STORM MOTION IS BRISK...TO THE NE AT
25KTS. THE HRRR SEEMS TO BE CAPTURING THE EARLY AFTERNOON SHOWER
COVERAGE WITH THE NAM AND GFS TOO WET FOR THIS EVENING. THE HRRR
SUGGESTS THE EVENING STORMS WILL BE MAINLY NEAR THE CONTINENTAL
DIVIDE AND PERHAPS THE EASTERN UINTAS. THEN ISOLATED TO SCATTERED
SHOWERS LINGER OVER THE SOUTH INTO SATURDAY MORNING.
IF TODAY IS ANY INDICATION OF HOW TOMORROW WILL BE...THEN SOME SHOWERS
AND THUNDERSTORMS ARE EXPECTED BUT NOTHING TOO IMPRESSIVE. MODELS
HAVE BEEN OVERDOING COVERAGE AND INTENSITY LAST FEW DAYS WITH BOTH
NAM AND GFS PAINTING WIDESPREAD PRECIPITATION WHICH JUST HASN`T
BEEN PANNING OUT. EVEN WITH DECENT UPPER LEVEL SUPPORT...THERE`S
NOT BEEN ANY REAL GOOD SURFACE TRIGGER TO GET STRONG CONVECTION
GOING. FOR SATURDAY...GFS SHOWING ANOTHER DAY OF WIDESPREAD PRECIP
WHILE NAM HAS REALLY PULLED BACK. FORECAST FOLLOWS NAM SO DROPPED
POPS GOOD AMT. THAT`S NOT TO SAY WE WON`T SEE ANY PRECIP...WE
WILL...SOME AFTN/EVENING THUNDERSTORMS ARE EXPECTED WITH SOME
HEAVY RAIN UNDER THE STRONGER CELLS. EXPECT COVERAGE WILL BE
SIMILAR TO TODAY. OF COURSE...HAVING SAID THAT CHANCE HAS NOW
INCREASED FOR TOMORROW TO BE VERY ACTIVE DAY. STAY TUNED. AS FAR
AS TEMPS ARE CONCERNED...PLENTY OF CLOUD COVER WILL KEEP TEMPS
NEAR NORMAL TO A FEW DEGREES BELOW.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 344 PM MDT FRI SEP 4 2015
A FEW DAYS OF NICE WEATHER ON TAP AS LOW PRESSURE SHIFTS NORTH AND
THE ASSOD TROUGH FORCES THE MOISTURE STREAM TO OUR EAST. A FEW
GARDEN VARIETY SHOWERS/STORMS MAY POPUP IN THE AFTERNOON/EVENING
MORE SO FOR MONDAY AND TUESDAY BUT THEY WILL BE VERY FEW AND FAR
BETWEEN FAVORING THE HIGHEST TERRAIN. MOST OF THE CWA WILL SEE
PLENTY OF SUN WITH SOME CU BUILDUP IN THE AFTERNOON WITH SCATTERED
SKIES BEING PREDOMINANT.
THE REMAINDER OF THE LONG TERM WILL SEE PIECES OF ENERGY ROTATING
AROUND THE PERIPHERY OF HIGH PRESSURE TO OUR SOUTH KICKING OFF
SOME SHOWERS/STORMS MAINLY OVER THE SAN JUANS. MEAN FLOW REMAINS
FROM THE WEST TO NORTHWEST KEEPING TEMPS SEASONABLE FOR THIS TIME
OF YEAR.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1059 PM MDT FRI SEP 4 2015
A LINE OF SHOWERS AND THUNDERSTORMS WILL MOVE ACROSS THE FORECAST
AREA FROM WEST TO EAST UNTIL ABOUT 09Z. KGJT...KRIL...KEGE...
KMTJ...AND KTEX WILL BE AFFECTED BY STORMS WITH A HIGH PROBABILITY
OF CONDITIONS BELOW ILS CUTOFFS AND WIND GUSTS TO ABOUT 40 MPH.
EACH OF THESE SITES HAS ABOUT A 20 PERCENT CHANCE OF MVFR CIGS AND
VSBYS UNTIL ABOUT 09Z.
FOR THE REST OF THE TIME PERIOD MOIST SOUTHWEST FLOW WILL KEEP
ISOLATED TO SCATTERED SHOWERS POPPING OVER THE EASTERN GREAT BASIN
TO THE ROCKIES OVERNIGHT. IN GENERAL THINGS QUIET DOWN LATE
TONIGHT WITH A RETURN OF THE SHOWER AND THUNDERSTORM ACTIVITY
TOMORROW AFTERNOON.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
UPDATE...CC
SHORT TERM...JOE/TGR
LONG TERM...TGR
AVIATION...CC
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
104 AM CDT SAT SEP 5 2015
.SHORT TERM...
235 PM CDT
THROUGH SATURDAY NIGHT...
SHOWERS AND THUNDERSTORMS HAVE BEEN MOST CONCENTRATED...BUT STILL
LARGELY SCATTERED...IN NORTHWEST INDIANA...AND EAST INTO EASTERN
ILLINOIS BUT WELL SOUTH...CLOSER TO A REMNANT FRONTAL BOUNDARY FROM
LAST NIGHT THAT STALLED OUT SOMEWHERE IN THE ROCHELLE TO JOLIET TO
VALPARAISO LINE. MOST OF THIS ACTIVITY HAS CONTINUED EAST. THIS
BOUNDARY STILL REMAINS...BUT WE ALSO NOW HAVE A LAKE BREEZE BOUNDARY
THAT IS NOW MAKING STEADY BUT NOW SLOWING INLAND PROGRESS THIS
AFTERNOON. THIS COMBINED WITH UPPER LEVEL LOW PRESSURE ATOP THE AREA
1500-2500 J/KG OF MIXED LAYER CAPE AWAY FROM THE LAKE IS RESULTING
IN ADDITIONAL ISOLATED DEVELOPMENT THIS AFTERNOON. THE BETTER
INSTABILITY AND CONVERGENCE SLIGHTLY COOLER TEMPS ALOFT STILL RESIDE
FROM THE KANKAKEE RIVER EASTWARD WILL ADDITIONAL DEVELOPMENT WILL
LIKELY CONTINUE. THESE STORMS STILL POSE A HEAVY RAINFALL THREAT IF
THEY CAN CONGEAL AS THEY ARE SLOW MOVING...WITH A LOW CONCERN FOR
GUSTY WINDS IN FORD/IROQUOIS COUNTY ILLINOIS INTO
BENTON/NEWTON/JASPER COUNTIES OF INDIANA...WITH THE HIGHER
CONCERN EAST INTO CENTRAL INDIANA.
LIKE YESTERDAY...THE LOSS OF DAYTIME HEATING...WE SHOULD SEE
ACTIVITY DIMINISH QUICKLY. THE UPPER LOW LINGERS IN THE REGION
OVERNIGHT. ANOTHER WEAK WAVE WILL ATTEMPT TO MOVE INTO THE UPPER
LEVEL RIDGE THAT WILL BUILD IN FROM THE WEST OVERNIGHT. MANY
GUIDANCE MEMBERS SUGGEST THAT THIS COUPLED WITH SOME RAMPING UP OF
ISENTROPIC LIFT AHEAD OF THIS FEATURE MAY TRIGGER SOME ISOLATED
SHOWERS OR THUNDERSTORMS LATE TONIGHT INTO EARLY SATURDAY. HAVE
MOVED TOWARD THE DRIER NAM SOLUTION AT THIS POINT IN TIME WHICH IS
REFLECTED IN THE EXPERIMENTAL HRRR AND HI-RES NMM/ARW AS WE DO NOT
FEELING FORCING IS STRONG ENOUGH TO TAP INTO ANY ELEVATED
INSTABILITY BUT WILL BE A PERIOD TO WATCH.
THE UPPER RIDGE IS OVER WESTERN ILLINOIS...WITH THE UPPER LOW
INCHING EASTWARD. LOW LEVEL SOUTHWESTERLIES SHOULD ALLOW WARMING ALL
THE WAY TO THE LAKEFRONT WITH 90S INLAND AND UPPER 80S AT THE LAKE.
A WEAKENING OF THE PRESSURE GRADIENT NEAR THE LAKE WOULD SUPPORT A
SE WIND SHIFT NEAR THE LAKE LATER IN THE DAY TO SUPPORT SOME
COOLING. HEAT INDICES WILL GET INTO THE MID TO UPPER 90S IN MANY
SPOTS. HAVE HELD ONTO THE SLIGHT CHANCE POPS FOR TOMORROW
AFTERNOON GIVEN THE MOIST/UNSTABLE ENVIRONMENT...BUT AT THIS POINT
MOST AREAS LOOK TO REMAIN DRY AS THE MAIN TRIGGER IS LACKING.
KMD
&&
.LONG TERM...
SUNDAY THROUGH FRIDAY...
300 PM...MULTIPLE FORECAST CONCERNS INCLUDING HIGH TEMPS SUNDAY
AND MONDAY...PRECIP CHANCES/TIMING LATE SUNDAY NIGHT THRU
WEDNESDAY ALONG WITH HEAVY RAIN POTENTIAL MONDAY NIGHT/TUESDAY.
UPPER RIDGE WILL BE RIGHT OVER THE AREA SUNDAY WITH DRY WEATHER AND
MOSTLY SUNNY SKIES. THIS SHOULD ALLOW TEMPS TO EASILY REACH THE
LOWER 90S INCLUDING ALONG MUCH OF THE IL LAKESHORE AS SOUTHWESTERLY
WINDS APPEAR STRONG ENOUGH THRU MID AFTERNOON TO PREVENT A LAKE
BREEZE. AS THE WINDS DIMINISH IN THE LATER AFTERNOON...WINDS WILL
LIKELY TURN SOUTHEASTERLY ALONG THE IL SHORE COOLING TEMPS A BIT.
WITH DEWPOINTS IN THE UPPER 60S/LOWER 70S...AFTERNOON HEAT INDEX
VALUES COULD CLIMB INTO THE UPPER 90S.
A FRONTAL BOUNDARY WILL MOVE SOUTHEAST ACROSS THE MIDWEST AND
WESTERN LAKES REGION SUNDAY NIGHT REACHING THE AREA MONDAY MORNING.
THE SLOWER TIMING FROM 24 HOURS AGO HAS HELD WITH THE MOST RECENT
GUIDANCE WITH MUCH OF THE AREA STAYING DRY UNTIL EARLY MONDAY
MORNING AND THE BEST CHANCES FOR PRECIP ACROSS NORTHWEST IL TOWARD
DAYBREAK. IT STILL APPEARS THAT PRECIP WILL BE DISSIPATING MONDAY
MORNING BUT TO WHAT EXTENT IS UNCERTAIN. HAVE INTRODUCED MORE OF A
GRADIENT WITH POPS DROPPING OFF TO SLIGHT CHANCE ACROSS THE
SOUTHEAST. POSSIBLE ADDITIONAL DEVELOPMENT MAY OCCUR LATER IN THE
AFTERNOON/EARLY EVENING. PRECIP COVERAGE AND ASSOCIATED CLOUD COVER
MAKE FOR A TRICKY TEMP FORECAST. STILL POSSIBLE TEMPS MAY CLIMB TO
NEAR 90 ACROSS THE SOUTHEAST MONDAY AFTERNOON.
THIS FRONTAL BOUNDARY THEN SLOWS AND STALLS ACROSS THE REGION MONDAY
NIGHT INTO TUESDAY AS AN UPPER WAVE LIFTS NORTHEAST ACROSS THE AREA.
WITH MOISTURE POOLING ALONG THIS BOUNDARY...PERIODS OF HEAVY RAIN
WITH THUNDERSTORMS IS LIKELY SOMEWHERE ACROSS THE REGION...A BIT
EARLY FOR SPECIFICS AND LOCATIONS. AS A STRONGER COLD FRONT MOVES
ACROSS THE AREA TUESDAY INTO TUESDAY NIGHT...THIS SHOULD PUSH THE
PRECIP CHANCES SOUTH OF THE AREA BUT STILL SOME UNCERTAINTY AS TO
HOW FAST THIS OCCURS. ANOTHER WAVE MOVES ACROSS THE AREA LATE NEXT
WEEK AS A LARGE UPPER TROUGH IS PROGGED TO MOVE ACROSS THE LAKES
REGION. GFS/ECMWF HAVE BEEN SHOWING THIS FOR SOME TIME...BUT IT
CONTINUES TO BE DELAYED. IF/WHEN THIS FINALLY ARRIVES...MUCH COOLER
TEMPS AND MUCH LOWER HUMIDITY WITH SPREAD ACROSS THE REGION. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* POSSIBLE PATCHY FOG EARLY THIS MORNING...MAY REDUCE VSBYS.
MAINLY WEST OF ORD/MDW.
* ISOLATED STORMS POSSIBLE EARLY THIS AFTERNOON...COVERAGE WILL
REMAIN LOW.
* LIGHT SOUTHWEST TO SOUTH WINDS...MAY ALLOW WINDS TO TURN
SOUTHEAST FROM A LAKE BREEZE CLOSER TO MDW AND POSSIBLY ORD
LATE IN THE AFTN.
BEACHLER
//DISCUSSION...UPDATED 06Z...
UPPER LEVEL SYSTEM CONTINUES TO ROTATE OVER THE GREAT LAKES
REGION...WITH A VERY LIGHT GRADIENT. THIS HAS ALLOWED WARM/HUMID
AIR TO FLOW NORTH. WITH LIGHT WINDS EARLY THIS MORNING AND VERY
MOIST ENVIRONMENT...PATCHY FOG MAY BEGIN TO DEVELOP. VSBYS COULD
BECOME REDUCED TO ARND 3-4SM...AND POSSIBLY FURTHER REDUCTIONS
WELL WEST OF THE METRO AREA.
A WEAK AREA OF FORCING WILL FLOAT OVERHEAD AFTER DAYBREAK AND
COULD TOUCH OFF AN ISOLATED SHOWER/THUNDERSTORM FOR FAR
WEST/NORTHWEST IL THRU MID-MORNING. THEN THIS AREA WILL
WEAKEN...WITH SEVERAL HI-RESOLUTION GUIDANCE INDICATING ADDITIONAL
ISOLATED SHOWERS OR STORMS DEVELOPING AFTER 18Z. SINCE COVERAGE IS
EXPECTED TO BE SO LOW AND EVEN THE CONFIDENCE IS LOW THAT IT WOULD
IMPACT THE AIRFIELDS...HAVE OPTED TO PULL THE PROB30 GROUP AND
LIMIT WITH A VCSH. THIS MAY NEED TO BE REVISED LATER THIS MORNING
AS CONFIDENCE COULD INCREASE WITH RESPECT TO TIMING/COVERAGE.
WINDS WILL GENERALLY REMAIN LIGHT OR LESS THAN 8KT FROM THE
SOUTHWEST...THEN BEGIN TO TURN SOUTHERLY LATER THIS MORNING. THE
GRADIENT SHOULD REMAIN LIGHT ENOUGH TO ALLOW WINDS TO TURN
SOUTHEAST AND COULD BECOME ONSHORE LATE THIS AFTERNOON FOR
MDW/ORD FROM A LAKE BREEZE.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN WIND DIR/SPEED...MEDIUM CONFIDENCE IN LAKE
BREEZE DEVELOPING.
* HIGH CONFIDENCE IN ISOLATED SHOWERS/THUNDERSTORMS
DEVELOPING...BUT VERY LOW CONFIDENCE IN TIMING/COVERAGE.
* MEDIUM CONFIDENCE IN EARLY MORNING VSBY FORECAST.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...VFR LIKELY. SOUTH WINDS.
MONDAY...CHANCE OF TSRA. SOUTHWEST WINDS.
TUESDAY...TSRA LIKELY. SOUTHWEST WINDS.
WEDNESDAY...CHANCE OF TSRA. NORTHEAST WINDS.
THURSDAY...SLIGHT CHANCE OF SHRA. NORTH WINDS.
MTF
&&
.MARINE...
315 PM...THE GRADIENT WILL SLOWLY TIGHTEN ACROSS LAKE MICHIGAN
THIS WEEKEND AS A LARGE TROUGH OF LOW PRESSURE OVER THE PLAINS
MOVES EAST WITH HIGH PRESSURE REMAINING OVER THE EASTERN U.S.
SOUTHERLY WINDS WILL LIKELY INCREASE INTO THE 15-25 KT RANGE ON
SUNDAY ESPECIALLY OVER THE NORTHERN PORTION OF THE LAKE. A COLD
FRONT WILL MOVE ACROSS THE LAKE MONDAY AFTERNOON INTO MONDAY
EVENING BUT THIS FRONT WILL SLOW AND STALL ACROSS THE SOUTHERN
LAKES REGION WITH WINDS TURNING BACK SOUTHERLY AHEAD OF ANOTHER
APPROACHING COLD FRONT THAT ARRIVES THURSDAY OR THURSDAY NIGHT
THOUGH CONFIDENCE REGARDING TIMING REMAINS LOW. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS TOPEKA KS
251 AM CDT SAT SEP 5 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 231 AM CDT SAT SEP 5 2015
Not much change to the overall pattern with southwest flow aloft
over the central and southern plains keeping the lee side trough in
place and a decent pressure gradient across eastern KS. Temperatures
will be a few degrees higher today so expect highs in the low to mid
90s with a few locations possibly reaching the upper 90s in central
KS. Southerly winds will again increase later today around 15 to 25
mph with gusts up to 35 mph. Later this morning a weak shortwave
will track over western NE and support showers and storms possibly
as far east as north central KS. The latest runs of the HRRR are now
hinting at isolated development in that area around sunrise, but
decided not to increase pops given the low uncertainty. The models
are showing mid level moisture spreading northward from the gulf
today coupled with cooler 850 mb temperatures across southeast KS.
This may lead to a weaker cap and an isolated shower or storm could
be possible south of I-35 this afternoon as daytime heating erodes
this cap. There is no obvious mid level support or any other focus
for lift so did not increase pops, but it could not be completely
ruled out. Tonight a cold front will drift eastward through the high
plains while several weak mid-level shortwaves track over the same
area. This should support storm development along the front in NE
during the overnight hours although have kept the northern forecast
area dry through sunrise.
.LONG TERM...(Sunday THROUGH Friday)
ISSUED AT 231 AM CDT SAT SEP 5 2015
Front still advancing across the Northern Plains on Sunday and
just starts to move into the far northwestern CWA by the late
afternoon hours. This leaves much of the area parked under the
thermal ridge for Sunday, with temperatures rising well into the
middle 90s. Heat indicies look to range from near 100 to 102F by
the afternoon hours. Northern counties may get some relief
overnight as front moves southward about halfway across the CWA,
but stalls out without a strong push to get the front south of the
area. As storms move into the area, some of the storms could be
strong with good instability available and dry air in the low
levels, but wind shear is not strong nor are the lapse rates
aloft. Front may actually retreat back toward the north on Monday
as next upper shortwave trof moves into the northern plains,
before getting a push southward in the overnight hours Monday
night into early Tuesday. Have highs Monday near 90 in the south
to middle 80s north and will need to watch progression of the
front for sensible weather effects.
Synoptic pattern over the Central Plains remains zonal in nature,
with surface front near the area for much of the remainder of the
week with shortwave trofs passing through the flow overhead.
Temperatures slowly fall Tuesday through Friday with rain chances
for much of the period given close proximity of the front. Upper
trof looks to deepen across the Great Lakes late in the week, and
usher in cooler high pressure behind.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z Saturday NIGHT)
ISSUED AT 1137 PM CDT FRI SEP 4 2015
VFR conditions are expected through the entire TAF period. Winds
will increase with gusts by mid to late morning, losing gusts
again by 23Z.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Sanders
LONG TERM...67
AVIATION...Barjenbruch
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
325 AM EDT SAT SEP 5 2015
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/MARINE
.SYNOPSIS...
ISSUED AT 308 AM EDT SAT SEP 5 2015
A WARM FRONT WILL LIFT NORTHWARD THROUGH THE REGION TODAY LEADING
TO SOME SHOWERS AND THUNDERSTORMS. HIGH PRESSURE CONTROLS OUR
WEATHER ON SUNDAY WHICH SHOULD END UP A MOSTLY DRY AND VERY WARM
DAY. THE CHANCES FOR SHOWERS AND THUNDERSTORMS WILL INCREASE AS WE
GO THROUGH LABOR DAY AND INTO TUESDAY AS A SLOW MOVING COLD FRONT
NEARS FROM THE WEST. THE TEMPERATURES WILL STILL END UP WELL ABOVE
NORMAL EARLY NEXT WEEK.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 308 AM EDT SAT SEP 5 2015
DENSE FOG HAS BEEN INCREASING OVER THE PAST FEW HOURS AND NOW
COVERS MUCH OF THE REGION. HRRR RUC SUGGESTS THE FOG WILL PERSIST
THROUGH DAYBREAK. WILL GO WITH AN ADVISORY AND CARRY IT UNTIL MID
MORNING. WE MAY SEE GRADUAL IMPROVEMENT IN THE VISIBILITIES FROM
SOUTH TO NORTH BEFORE DAYBREAK AS THE ELEVATED WARM FRONT MOVES
IN.
THE ATMOSPHERE WILL BE UNSTABLE THROUGH THE DAY. SOME LIFT ARRIVES
WITH THE ELEVATED WARM FRONT MOVING IN THIS MORNING FROM THE
SOUTH. THEREFORE WILL KEEP THE MENTION OF SHOWERS AND
THUNDERSTORMS IN THE FORECAST. LITTLE OR NO FORCING IS AROUND
TONIGHT INTO SUNDAY. WILL KEEP IT DRY FOR NOW. THE ATMOSPHERE
BECOMES RATHER UNSTABLE ON SUNDAY...SO WILL NEED TO MONITOR THIS
CLOSELY. SUNDAY SHOULD BE ONE OF THE WARMEST DAYS OF THE SEASON AS
THE LOW LEVEL THERMAL RIDGE ADVECTS IN FROM THE SOUTHWEST.
WILL FEATURE AN INCREASING RISK FOR SHOWERS AND THUNDERSTORMS ON
LABOR DAY. MODELS VARY ON THE TIMING OF ANY PRECIPITATION. HOWEVER
GIVEN THE APPROACHING FRONT DURING THE AFTERNOON WILL ENCOUNTER AN
UNSTABLE AIRMASS...IS SEEMS THAT A RISK FOR THUNDERSTORMS WILL
EXIST. WILL HIGHLIGHT THE AFTERNOON FOR POSSIBLE THUNDERSTORMS.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 308 AM EDT SAT SEP 5 2015
MAIN FOCUS IS CURRENTLY ON THE THREAT FOR HEAVY RAINFALL MONDAY
NIGHT THROUGH TUESDAY NIGHT WITH SOME TRAINING THUNDERSTORMS
POSSIBLE IN ASSOCIATION WITH MAINLY UNIDIRECTIONAL WINDS IN THE
PROFILE...A VERY MOIST AIRMASS...AND A WARM FRONT LIFTING THROUGH
DURING THIS PERIOD. MANY AREAS NEAR AND NORTH OF I-96 ARE EXPECTED
TO RECEIVE ONE TO TWO INCHES OF RAIN BY WEDNESDAY MORNING WITH
HIGHER AMOUNTS QUITE POSSIBLE.
I BELIEVE THERE ARE SOME KEY INGREDIENTS COMING IN PLACE FOR LOCALLY
EXCESSIVE RAINFALL ACROSS WEST CENTRAL AND SOUTHWEST LOWER MI. AS
HAS BEEN MENTIONED MANY TIMES...A WEAK COLD FRONT WILL WASH OUT
ACROSS THE CWA MONDAY...WHICH WILL BECOME STATIONARY AND THEN LIFT
NORTH AS A WARM FRONT TUESDAY. JUST HOW FAR NORTH THIS BOUNDARY
LIFTS IS QUESTIONABLE GIVEN NUMEROUS AREAS OF CONVECTION THAT COULD
SUPPRESS THE FRONT SOUTHWARD. CURRENTLY FAVORING THE ECMWF WITH THIS
SYSTEM GIVEN A FEW DIFFERENT GYRATIONS NOTED WITH THE GFS RECENTLY
WITH HOW QUICK THE BOUNDARY WILL MOVE THROUGH.
DEEP LAYER RH (H1000-H500) ON TUESDAY COULD TOP 90% FOR A GOOD
PORTION OF THE CWA...ESPECIALLY FROM GRR TO THE NORTH. ALL OF THE
MODELS ARE ALSO SHOWING SOME H1000-H700 WIND CONVERGENCE. A 20 KT
LLJ AT 00Z TUES STRENGTHENS TO 30-35 KT BY 00Z WED. HIGHER UP...WE
WILL BE SQUARELY IN THE RIGHT ENTRANCE REGION OF A 100 KT JET STREAK
AS H500 POSITIVE VORTICITY ADVECTION MOVES INTO THE CWA DURING THE
MORNING AND AFTERNOON HOURS. NEAR THE SURFACE...THE WARM FRONT WILL
BE DRAPED ACROSS THE CWA NEAR GRR AT 12Z TUESDAY...POSSIBLY LIFTING
NORTH TOWARD ROUTE 10 BY 18Z. DEW POINT READINGS AROUND 70 COUPLED
WITH PW VALUES OF 2.00-2.25" STRONGLY SUGGEST ANY STORMS WOULD BE
CAPABLE OF HEAVY DOWNPOURS. IF THE NWP SOLUTIONS CONTINUE SUPPORTING
THESE DETAILS...COULD FORESEE A FLOOD THREAT FOR AREAS THAT GET THE
MOST PERSISTENT RAINS.
IN TERMS OF ANY SEVERE WEATHER THREAT...IT IS UNCLEAR AT THIS TIME.
ONGOING CONVECTION EARLY TUESDAY COULD HAMPER ANY DESTABILIZATION
DURING THE AFTERNOON. SFC BASED CAPE IS NOT MUCH MORE THAN 1000 J/KG
FOR THE AREA ON TUESDAY...THOUGH BULK SHEAR IS LOOKING MUCH BETTER
OFF THE ECMWF AT AROUND 35-40 KTS. IT IS ALSO SHOWING 100-150 M2/S2
OF 0-1 KM HELICITY COURTESY OF THE WARM FRONT NEARBY. NOT OUT OF THE
QUESTION THERE COULD BE SOME STRONGER STORMS CAPABLE OF GUSTY WINDS
AND SOME HAIL IF WE CAN DESTABILIZE SUFFICIENTLY.
BEYOND THIS PERIOD...LOOKING AT A PATTERN CHANGE FOR THE SECOND HALF
OF THE WEEK AND THE WEEKEND IN PARTICULAR. TROPICAL STORM IGNACIO
WILL GET SWEPT UP IN MID LEVEL FLOW OVER THE GULF OF ALASKA.
FOLLOWING THE ECMWF H500 HEIGHT FIELD...THIS HELPS DIG A TROUGH INTO
THE GREAT LAKES FOR FRIDAY AND SATURDAY...WITH CHILLY TEMPS AND
SCATTERED SHOWERS EXPECTED BY SATURDAY WITH HIGHS STRUGGLING INTO
THE 60S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 142 AM EDT SAT SEP 5 2015
AREAS OF FOG WILL LIKELY BE IN AND OUT OF THE TAF SITES THROUGH
12Z OR 13Z. ABRUPT CHANGES IN VIS/CIG CAN BE EXPECTED AS THE FOG
DEVELOPS MAINLY NORTH OF THE AZO/BTL TERMINALS WHERE MORE CLEARING
HAS OCCURRED. VCTS THREAT EXISTS THIS MORNING MAINLY FOR AZO/BTL
PER HIGH RES MODEL GUIDANCE AND RADAR COLLABORATION. DAYTIME POP-
UP STORMS ARE POSSIBLE JUST ABOUT ANYWHERE TODAY WITH THE THREAT
ENDING CLOSE TO DARK.
&&
.MARINE...
ISSUED AT 308 AM EDT SAT SEP 5 2015
WINDS AND WAVES INCREASE SUNDAY INTO SUNDAY NIGHT AS THE WARM AIR
ADVECTION STRENGTHS AHEAD OF THE APPROACHING COLD FRONT. WILL NEED
TO MONITOR LITTLE AND BIG SABLE POINTS FOR A POSSIBLE SMALL CRAFT
ADVISORY AND ASSOCIATED BEACH HAZARDS. RIGHT NOW I HAVE WAVES
INCREASING TO 2 TO 4 FEET.
&&
.HYDROLOGY...
ISSUED AT 1054 AM EDT FRI SEP 4 2015
NO CONCERNS EXIST IN THE NEAR TERM. QUESTIONS ARISE GOING INTO NEXT
WEEK AS A BOUNDARY DRAPES ITSELF SOMEWHERE THROUGH OR NEAR THE GREAT
LAKES REGION.
AREA RIVERS HAVE RESPONDED PRETTY WELL TO YESTERDAYS RAINFALL.
LOCALIZED TOTALS OF MORE THAN TWO INCHES RESULTED IN DECENT UPWARD
TRENDS AT A FEW FORECAST POINTS. MOST NOTABLE IS SYCAMORE CREEK AT
HOLT...WHICH HAS LEVELED OFF ABOUT A FOOT BELOW ADVISORY CRITERIA.
PROVIDED THAT ADDITIONAL RAINFALL IS LIMITED...HOLT SHOULD CONTINUE
ITS DOWNWARD TREND. OTHER SITES HAVE ALSO LEVELED OFF AND RESPONSES
HAVE BEEN MINOR.
RAINFALL THROUGH THE WEEKEND IS EXPECTED TO BE SCATTERED WITH
LOCALIZED HEAVY RAIN POSSIBLE IN OR AROUND THUNDERSTORMS. CONDITIONS
ARE NOT FAVORABLE FOR WIDESPREAD HEAVY RAIN. A PATTERN CHANGE WILL
TAKE PLACE NEXT WEEK AND ITS ASSOCIATED BOUNDARY LOOKS TO BE MOVING
SLOWLY. DIFFERENCES IN LONG RANGE MODELS PUT A CAP ON ANY HIGH
CONFIDENCE. HOWEVER...PWATS ARE 1.5-2.0 INCHES AND THE SLOW
PROGRESSION OF THE BOUNDARY COULD RESULT IN PRETTY DECENT RAINFALL
TOTALS MONDAY THROUGH WEDNESDAY. THE SETUP MAY SUGGEST MORE THAN AN
INCH...WITH AREAS EXCEEDING A COUPLE OF INCHES IF STORMS ARE SLOW
MOVERS. THIS WILL LIKELY BE THE FOCUS HYDRO-WISE OVER THE NEXT
FEW DAYS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR MIZ037>040-
043>046-050>052-056>059-064>067.
LM...NONE.
&&
$$
SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...HOVING
AVIATION...HOVING
HYDROLOGY...JAM
MARINE...MJS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
145 AM EDT SAT SEP 5 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 323 PM EDT FRI SEP 4 2015
A WEAK LOW PRESSURE AREA WILL HELP TRIGGER SHOWERS AND POSSIBLY A
THUNDERSTORM THIS EVENING INTO EARLY TONIGHT OVER NORTHERN LOWER
MICHIGAN AS IT DRIFTS NORTHWARD. BEHIND IT...WARM AND HUMID AIR WILL
RETURN FROM THE SOUTH WITH SLIGHT CHANCES FOR SHOWERS AND
THUNDERSTORMS. SUNDAY WILL BE HOT AND DRY WITH HIGHS NEAR 90. THIS
WILL BE FOLLOWED BY A WET PERIOD LASTING LABOR DAY THROUGH TUESDAY
AS A COLD FRONT PASSES. BEHIND THIS FRONT...THE LATTER HALF OF THE
WORK WEEK WILL FEATURE MUCH DRIER CONDITIONS AND HIGHS IN THE LOW TO
MID 70S.
&&
.UPDATE...
ISSUED AT 1049 PM EDT FRI SEP 4 2015
DID NOT MAKE BIG CHANGES TO THE FORECAST...BUT DID ADD AREAS OF
FOG WORDING VERSUS PATCHY AS WE SHOULD SEE FOG IN MANY AREAS.
MASON AND CHARLOTTE HAVE ALREADY HAD VISIBILITIES DIP TO AROUND 1
MILE. EXPECTING FOG TO BECOME MORE PREVALENT THROUGH THE NIGHT
GIVEN LIGHT WINDS AND A MOIST AIR MASS.
AS FOR PRECIP CHANCES...FEEL WE MAY SEE ISOLATED TO SCATTERED
SHOWERS AND STORMS DEVELOP NEAR AND ESPECIALLY SOUTH OF INTERSTATE
96. THE RAP13 MODEL AS WELL AS THE NAM ARE INDICATING A WEAK LLJ
DEVELOPING ALONG WITH SOME MODEST 850MB MOISTURE TRANSPORT. THE
SOUTHERN CWA WILL BE NEAR A WEAK 850MB WARM FRONTAL FEATURE THAT
CAN BE SEEN IN THE 850MB DEW POINT FIELDS. HAVE ISOLATED SHOWERS
POSSIBLE NORTH WITH ISOLATED SHOWERS AND STORMS TO THE SOUTH.
LATEST RUN OF THE HRRR HAS THE SHOWERS AND STORMS DEVELOPING
TOWARD INTERSTATE 94 AROUND DAYBREAK. OTHER CONVECTION ALLOWING
MODELS HAVE ACTIVITY DEVELOPING SOONER IN THE NIGHT. NOTHING
STRONG...BUT WE WILL BE KEEPING AN EYE ON THE RADAR OVERNIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 323 PM EDT FRI SEP 4 2015
CONTINUED TO TRIM RAIN CHANCES FOR THIS EVENING AND EARLY TONIGHT AS
LOW LEVEL FORCING CONTINUES WITH SURFACE LOW DRIFTING NORTH. SOME
CONVECTION ALLOWING MODELS SUGGEST SHOWERS AND THUNDERSTORMS WILL
DEVELOP OR SPREAD NORTH TOWARDS THE I-94 CORRIDOR SATURDAY
MORNING...POSSIBLY ASSOCIATED WITH REMNANTS OF THE ONGOING
CONVECTION ACROSS NORTHERN INDIANA. ALSO EXPECT AT LEAST PATCHY FOG
AGAIN SATURDAY MORNING...BUT THIS WILL AGAIN BE TRICKY GIVEN THE
POTENTIAL FOR LOW CLOUDS.
SUNDAY STILL LOOKS HOT WITH HIGHS NEAR 90. ALSO STILL EXPECT IT TO
BE DRY PER GFS FORECAST SOUNDINGS...BUT AS NOTED IN THE PREVIOUS
DISCUSSION...LAKE BREEZE SHOWERS OR STORMS ARE NOT OUT OF THE
QUESTION AND THIS WILL HAVE TO BE WATCHED.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 323 PM EDT FRI SEP 4 2015
WE WILL SEE A BIG PATTERN CHANGE IN THE EXTENDED AS UPPER RIDGING AT
THE BEGINNING OF THE PERIOD IS REPLACED BY UPPER TROUGHING BY THE
END. IN BETWEEN WE ARE DEALING WITH A SLOW MOVING FRONT THAT SHOULD
BRING PERIODS OF RAIN...POSSIBLY HEAVY...FROM LATE MONDAY INTO EARLY
WEDNESDAY.
FORECAST UNCERTAINTY IS NOT SO MUCH WITH THE TIMING OF THAT INITIAL
FRONT BUT WITH THE HANDLING OF A SECONDARY FRONT THAT FOLLOWS AS THE
UPPER TROUGH DEEPENS. THE SPLIT BETWEEN THE SOLUTIONS VARIES FROM A
MUCH QUICKER GFS SOLUTION THAT BRINGS IT IN WEDNESDAY NIGHT AND
THURSDAY TO THE EURO WHICH HOLDS IF OFF UNTIL FRIDAY. DECIDED TO GO
TOWARDS THE LATER SOLUTION...SO KEPT THURSDAY DRY FOR NOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 142 AM EDT SAT SEP 5 2015
AREAS OF FOG WILL LIKELY BE IN AND OUT OF THE TAF SITES THROUGH
12Z OR 13Z. ABRUPT CHANGES IN VIS/CIG CAN BE EXPECTED AS THE FOG
DEVELOPS MAINLY NORTH OF THE AZO/BTL TERMINALS WHERE MORE CLEARING
HAS OCCURRED. VCTS THREAT EXISTS THIS MORNING MAINLY FOR AZO/BTL
PER HIGH RES MODEL GUIDANCE AND RADAR COLLABORATION. DAYTIME POP-
UP STORMS ARE POSSIBLE JUST ABOUT ANYWHERE TODAY WITH THE THREAT
ENDING CLOSE TO DARK.
&&
.MARINE...
ISSUED AT 323 PM EDT FRI SEP 4 2015
WINDS AND WAVES EXPECTED TO STAY LOW THROUGH SATURDAY NIGHT WITH A
SLIGHT UPTICK SUNDAY AHEAD OF AN APPROACHING COLD FRONT. LABOR DAY
COULD FEATURE WAVES OF 3 OR MORE FEET NORTH OF MUSKEGON AS WINDS
FROM THE SOUTH PERSIST AND CONTINUE TO INCREASE.
&&
.HYDROLOGY...
ISSUED AT 1054 AM EDT FRI SEP 4 2015
NO CONCERNS EXIST IN THE NEAR TERM. QUESTIONS ARISE GOING INTO NEXT
WEEK AS A BOUNDARY DRAPES ITSELF SOMEWHERE THROUGH OR NEAR THE GREAT
LAKES REGION.
AREA RIVERS HAVE RESPONDED PRETTY WELL TO YESTERDAYS RAINFALL.
LOCALIZED TOTALS OF MORE THAN TWO INCHES RESULTED IN DECENT UPWARD
TRENDS AT A FEW FORECAST POINTS. MOST NOTABLE IS SYCAMORE CREEK AT
HOLT...WHICH HAS LEVELED OFF ABOUT A FOOT BELOW ADVISORY CRITERIA.
PROVIDED THAT ADDITIONAL RAINFALL IS LIMITED...HOLT SHOULD CONTINUE
ITS DOWNWARD TREND. OTHER SITES HAVE ALSO LEVELED OFF AND RESPONSES
HAVE BEEN MINOR.
RAINFALL THROUGH THE WEEKEND IS EXPECTED TO BE SCATTERED WITH
LOCALIZED HEAVY RAIN POSSIBLE IN OR AROUND THUNDERSTORMS. CONDITIONS
ARE NOT FAVORABLE FOR WIDESPREAD HEAVY RAIN. A PATTERN CHANGE WILL
TAKE PLACE NEXT WEEK AND ITS ASSOCIATED BOUNDARY LOOKS TO BE MOVING
SLOWLY. DIFFERENCES IN LONG RANGE MODELS PUT A CAP ON ANY HIGH
CONFIDENCE. HOWEVER...PWATS ARE 1.5-2.0 INCHES AND THE SLOW
PROGRESSION OF THE BOUNDARY COULD RESULT IN PRETTY DECENT RAINFALL
TOTALS MONDAY THROUGH WEDNESDAY. THE SETUP MAY SUGGEST MORE THAN AN
INCH...WITH AREAS EXCEEDING A COUPLE OF INCHES IF STORMS ARE SLOW
MOVERS. THIS WILL LIKELY BE THE FOCUS HYDRO-WISE OVER THE NEXT
FEW DAYS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...DUKE
SYNOPSIS...TJT
SHORT TERM...TJT
LONG TERM...OSTUNO
AVIATION...HOVING
HYDROLOGY...JAM
MARINE...TJT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
117 AM EDT SAT SEP 5 2015
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 318 PM EDT FRI SEP 4 2015
AN UPPER RIDGE IS STRETCHING FROM A HIGH OVER TX TO WRN UPPER
MI...WRAPPING INTO WRN QUEBEC AROUND A WEAK UPPER DISTURBANCE OVER
LOWER MI. THIS HAS RESULTED IN CLEAR SKIES OVER MOST OF THE
CWA...WHILE SERN SECTIONS HAVE SOME CLOUD COVER. SOME CU IS BREAKING
OUT OVER ERN AND SCENTRAL UPPER MI...AS LOW LEVEL MOISTURE MOVES IS
AHEAD OF THE SLOWLY NORTHWARD MEANDERING DISTURBANCE. UP TO 500J/KG
OF CAPE IS BEING ANALYZED BY THE RAP OVER ERN UPPER MI...WHERE MANY
HIGH-RES MODELS SHOW SOME ISOLATED SHOWERS AND THUNDERSTORMS
BREAKING OUT OVER THE NEXT FEW HOURS. THESE SHOWERS AND
THUNDERSTORMS DIE OFF TONIGHT...BUT WE COULD SEE SOME ADDITIONAL
SHOWERS OVER THAT DIRECTION AS THE DISTURBANCE MOVES OVER. SHOULD
SEE FOG TONIGHT OVER MAINLY CENTRAL AND ERN UPPER MI AS THE LOW
LEVEL MOISTURE CONTINUES TO MOVE IN FROM THE SE.
SAT LOOKS WARMER AS SW FLOW INCREASES AND 850MB TEMPS INCREASE FROM
AROUND 15C TODAY TO 18-21C BY 00Z SUN. EXPECT HIGHS IN THE 70S NEAR
LAKE MICHIGAN...BUT IN THE 80S ELSEWHERE...AND EVEN 90 IN BARAGA. A
WEAK SHORTWAVE MOVING W OF THE AREA LATE TONIGHT INTO SAT MORNING
MAY LEAD TO SOME ISOLATED SHOWERS AND THUNDERSTORMS OVER WRN UPPER
MI. ANOTHER SHORTWAVE MOVES W OF THE AREA SAT
AFTERNOON/EVENING...WHICH MAY LEAD TO SHOWERS AND THUNDERSTORMS OVER
WRN UPPER MI. THE HIGH-RES WRF ARW AND NMM ALONG WITH THE GFS HAVE
THE MOST PRECIP...BUT THE GFS IS VERY MUCH AN OUTLIER AND THE WRFS
ARE MORE REALISTIC. OTHER MODELS ARE DRY FOR THE MOST PART. AS
ALWAYS IN THESE SITUATIONS...CONVECTIVE DEVELOPMENT IS
UNCERTAIN...BUT IT DOES APPEAR THAT ISOLATED TO SCATTERED PRECIP IS
MORE LIKELY. IF AFTERNOON CONVECTION DOES FORM...SOME OF THE STORMS
OVER FAR WRN UPPER MI COULD BE STRONG TO POSSIBLY SEVERE AS MUCAPES
WILL BE 1000-2000J/KG AND 0-6KM BULK SHEAR AROUND 20KTS. THINK
SEVERE CHANCES ARE LOW...BUT IT CAN NOT BE RULED OUT.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 500 PM EDT FRI SEP 4 2015
MODELS SUGGEST THAT WITH A GRADUAL PATTERN PROGRESSION...THE
MID/UPPER LEVEL RIDGE DOMINATING THE CNTRL CONUS WILL TRANSITION TO
A MORE ZONAL PATTERN EARLY NEXT WEEK AND A TROUGH OVER THE CNTRL
CONUS BY THE END OF THE WEEK. SO...ABOVE NORMAL TEMPERATURES WILL
GIVE WAY TO MORE SEASONAL CONDITIONS BY TUESDAY AND BELOW NORMAL
TEMPS BY WED-FRI WITH MORE FALL-LIKE WEATHER.
SAT NIGHT...WITH SW MID/UPPER LEVEL FLOW FROM THE PLAINS TO WRN LAKE
SUPERIOR...THE POTENTIAL WILL REMAIN FOR WEAK SHORTWAVES TO LIFT
INTO THE AREA THAT COULD TRIGGER SCT SHRA/TSRA. LOWER END CHANCE
POPS FOR SHRA/TSRA CHANCES WILL BE CONFINED TO WRN UPPER MI.
SUNDAY THROUGH SUNDAY NIGHT...A VIGOROUS SHORTWAVE TROUGH OVER SW
SASK LIFTING INTO MANITOBA WILL HELP FLATTEN THE RIDGE. A SFC TROUGH
WILL DEVELOP INTO NRN ONTARIO WITH A COLD FRONT THROUGH THE UPPER MS
VALLEY LATE SUNDAY MOVING THROUGH UPPER MI BY LATE SUN NIGHT INTO
EARLY MON. ALTHOUGH SOME SHRA/TSRA MAY BRUSH THE WRN CWA...EXPECT
CAPPING WILL BE STRONG ENOUGH DURING THE PEAK HEATING AND HIGHER
INSTABILITY TO MINIMIZE SHRA/TSRA CHANCES. WITH 850 MB TEMPS NEAR
20C...TEMPS WILL CLIMB WELL ABOVE NORMAL WITH HIGHS IN THE UPPER 80S
TO POSSIBLY 90 IN SSW DOWNSLOPE FLOW LOCATIONS.
AS THE FRONT APPROACHES SUNDAY NIGHT...THE COMBINATION OF HEIGHT
FALLS...LOW LEVEL CONV NEAR THE FRONT AND THE LIKELIHOOD OF WEAKER
SHORTWAVES APPROACHING THE AREA IN SW FLOW FROM THE PLAINS WILL
SUPPORT LIKELY POPS. WITH MUCAPE VALUES TO AT LEAST 1K J/KG AND 0-
6KM SHEAR OF 30-35 KNOTS...SOME STRONGER STORMS WILL BE POSSIBLE.
HOWEVER...WITH HIGH FREEZING LEVELS...PWAT VALUES TO AROUND 2.0
INCHES...AND POTENTIAL FOR BACKBUILDING CONVECTION FROM 45 KT SW
INFLOW...PER CORFIDI VECTORS...HEAVY RAIN MAY BE THE GREATER HAZARD.
MON...SOME SHRA AND POSSIBLY TSRA MAY LINGER INTO EARLY MONDAY OVER
THE ERN CWA...PER SLOWER ECMWF. OTHERWISE...DRIER AIR AND CLEARING
WILL MOVE IN WITH WRLY LOW LEVEL FLOW.
TUE-FRI...PCPN CHANCES ARE MORE UNCERTAIN GIVEN LARGER MODEL
DIFFERENCES WITH THE STRENGTH AND POSITION OF SHORTWAVES AND THE
INTERACTION WITH THE FRONT TO THE SOUTH OF THE REGION. FOR
NOW...ONLY LOWER END SHRA CHANCES WERE INCLUDED...PER MDLS
CONSENSUS. WITH THE MID LEVEL TROUGH DEVELOPING OVER THE
REGION...ENOUGH COLD AIR MAY MOVE IN...PER ECMWF WITH 850 MB
TEMPS DOWN TO 3C...TO SUPPORT LAKE ENHANCED RAIN BY FRI.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 116 AM EDT SAT SEP 5 2015
AN INCREASE IN MOISTURE FROM THE SE SHOULD RESULT IN FOG AND SOME
STRATUS DEVELOPMENT OVERNIGHT...MAINLY AT KSAW WHICH IS CLOSER TO
THE ARRIVING MOISTURE POOL AND DUE TO BETTER UPSLOPING. AT
KSAW...EXPECT IFR CONDITIONS WITH THE POTENTIAL OF A PERIOD OF LIFR
CONDITIONS AROUND SUNRISE. A PERIOD OF MVFR VIS IS EXPECTED AT KCMX
AROUND SUNRISE...BUT KIWD WILL PROBABLY STAY VFR WITH A DOWNSLOPE
WIND THRU THE NIGHT. FOG/STRATUS WILL BURN OFF IN THE
MORNING...RESULTING IN VFR CONDITIONS PREVAILING FROM MID MORNING
INTO THE EVENING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 318 PM EDT FRI SEP 4 2015
EAST TO NORTHEAST WINDS OF 10-15KT WILL CONTINUE UNTIL THE NEXT
CHANCE FOR WINDS GREATER THAN 20KT COMES ON MONDAY BEHIND A COLD
FRONT. FOG WILL CONTINUE TO BE PATCHY ACROSS THE LAKE UNTIL THE COLD
FRONT MOVES THROUGH.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...TITUS
LONG TERM...JLB
AVIATION...ROLFSON
MARINE...TITUS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
400 AM CDT SAT SEP 5 2015
.SYNOPSIS...
ISSUED AT 400 AM CDT SAT SEP 5 2015
WEAK EMBEDDED SHORT WAVE MOVING QUICKLY ACROSS THE CENTRAL
ROCKIES AND ONTO THE HIGH PLAINS IN SWRLY FLOW ALOFT WORKING IN
CONCERT WITH LLJ TO GENERATE SHRA AND ISOLD TSRA ACROSS PORTIONS
OF WRN NEB EARLY THIS MORNING. MEANWHILE UPPER TROUGH AND
ASSOCIATED LOW OVER THE PAC NW STARTING TO MOVE EWD WHILE HEIGHTS
RISE ACROSS THE PLAINS. THESE TWO THINGS CONTRIBUTING TO
TIGHTEN/INCREASE THE UPPER FLOW AHEAD OF THE LOW IN THE NW.
MOISTURE AND ASSOCIATED CONVECTIVE ACTIVITY FROM TROPICAL STORM
KEVIN MOVING ONSHORE ON THE BAJA PENINSULA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 400 AM CDT SAT SEP 5 2015
FORECAST ISSUES FOR EARLY THIS MORNING INVOLVES THE POTENTIAL FOR
ADDITIONAL CONVECTIVE DEVELOPMENT IN SRN/WRN NEB WHICH SEVERAL OF
THE CAMS SUGGEST WILL HAPPEN THROUGH THE MORNING. RADAR ECHOES
OVER THE LAST FEW HOURS HAVE INCREASED IN THE ERN PANHANDLE...BUT
NEW DEVELOPMENT AS PER THE OPERATIONAL HRRR HAS YET TO OCCUR
ASSOCIATED WITH THE NWD ADVANCING WARM FRONT OVER SRN NEB. SHORT
RANGE MODELS DO HAVE ELEVATED INSTABILITY PRESENT AND SPC
MESOANALYSIS BASED ON RAP SHOWS DEEP MOIST CONVERGENCE INCREASING
TO SUPPORT THIS IDEA. HAVE TRENDED THE HOURLY POP GRIDS TO
REFLECT THIS OCCURRING...DESPITE EXP HRRR AND NSSL WRF NOT
EVOLVING IN THIS MANNER.
ATTENTION THEN TURNS TO ADDITIONAL TSRA DEVELOPMENT THIS
AFTERNOON. AS PREVIOUSLY MENTIONED SHORT WAVE CONTINUES TO MOVE
NEWD INTO THE DAKOTAS TODAY...WEAK LARGE SCALE HEIGHT FALLS ALSO
MOVE OUT OF THE AREA. HOWEVER AS PAC NW UPPER LOW CONTINUES TO
MOVE EWD GOOD HEIGHT FALLS DEVELOP ACROSS WRN MT. THE INCREASED
SWRLY FLOW AHEAD OF THIS FEATURE ALLOWS THE SFC LOW TO REDEVELOP
OVER ERN WY THIS AFTERNOON. AS THIS OCCURS...DEEPER MIXING SOUTH
OF THE SFC LOW WILL DEVELOP THIS AFTERNOON SERVING TO LOWER DEW
POINTS ACROSS THE PANHANDLE. AT THIS SAME TIME...INCREASING SERLY
LOW LEVEL FLOW IN THE TIGHTENING SFC GRADIENT WILL INCREASE DEW
POINTS/LOW LEVEL MOISTURE FURTHER EAST OVER TIME. THE RESULT IS
TO TIGHTEN THE GRADIENT AND EVENTUALLY TO DEVELOP THUNDERSTORMS
ASSOCIATED WITH THIS BOUNDARY. SUITE OF MODELS CONTAIN A WIDE
VARIETY OF SOLUTIONS HOWEVER IN HOW EXTENSIVE THE QPF WILL
BE...IF AT ALL. NAM SUGGESTS A LARGE INCREASE IN PW BY AFTERNOON
/PRIOR TO CONVECTIVE DEVELOPMENT IN THE MODEL/ ASSOCIATED WITH
THE FETCH OF MID/UPPER LEVEL MOISTURE ORIGINATING FROM THE ERN
PAC TROPICS VIA THE SWRLY FLOW. IF DEEP MOIST CONVECTION CAN
DEVELOP...THE WARM MOIST MID LEVELS WOULD ALLOW FOR A CAPE
PROFILE MORE CONDUCIVE TO HEAVY RAIN PRODUCING STORMS AND SHEAR
OF 25-30KTS WOULD BE MARGINAL FOR DEVELOPING STRONG STORMS. AS
ALWAYS HOWEVER SMALL SCALE STORM INTERACTIONS MAY ALLOW FOR MORE
ROBUST DEVELOPMENT ON OCCASION.
TEMPERATURES TODAY WILL BE TRICKY DUE TO LEFT OVER CLOUD COVER
FROM ONGOING CONVECTION AS WELL AS NEW CLOUD COVER FROM
ADDITIONAL DEVELOPMENT THIS AFTERNOON. ASSUMING SRN AREAS WOULD
RECEIVE BEST INSOLATION FOR A LONGER PERIOD OF TIME AND THEREFORE
MAXES ARE HIGHER THERE...THOUGH 90S WILL AGAIN BE COMMON TODAY.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 400 AM CDT SAT SEP 5 2015
SOUTHWEST FLOW TO START THE WEEK TRANSITIONS TO MORE ZONAL FLOW AS
AN UPPER LEVEL LOW LIFTS ACROSS THE NORTHERN ROCKIES INTO THE
CANADIAN PLAINS. A COUPLE OF COLD FRONTS WILL RESULT IN FALLING
TEMPS FOR THE WEEK. MAIN CONCERN IN THE EXTENDED WILL BE TIMING THE
COOL DOWNS AND LOW POP CHANCES THROUGHOUT THE PERIOD.
SUNDAY INTO MONDAY SW FLOW WILL TAP SOME PACIFIC MOISTURE. MODELS
SHOWING SOME MOISTURE FROM THE EASTERN PACIFIC TROPICAL SYSTEMS
GET DRAWN ACROSS THE 4 CORNERS AND TOWARDS THE HIGH PLAINS. THIS
MAY BE ENOUGH TO INCREASE THE MOISTURE IN THE MID/UPPER LEVELS THAT
CAN BE TAPPED BY WEAK DISTURBANCES RIDING ACROSS THE AREA. MODELS
HAVE INCREASE THE LIGHT QPF OVER THE CWA AND CAN NOT ARGUE
NEEDING LOW POPS WITH EACH PASSING WAVE.
MID WEEK A COLD FRONT WILL PUSH ACROSS THE AREA. TIMING OF THE
FRONT AND BETTER MOISTURE RESULTS IN BEST CHANCE FOR PRECIP TO BE
ACROSS THE EASTERN ZONES. BEHIND THE FRONT TEMPS COOL INTO THE
70S...WHICH WOULD BE BELOW NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1127 PM CDT FRI SEP 4 2015
ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED THE REST OF
TONIGHT IN WESTERN NEBRASKA. CONFIDENCE IN SHOWERS/THUNDERSTORMS
OCCURRING BEFORE 15Z IS LOW. IN FACT...THE PROBABILITY OF
SHOWERS/THUNDERSTORMS THROUGH THE PERIOD IS 30 PERCENT OR LOWER
WHICH DOES NOT INSPIRE A LOT OF CONFIDENCE THAT THEY WILL OCCUR
AT LBF OR VTN. THE BEST CONSENSUS AMONG THE EVENING MODEL RUNS
WOULD BE THAT THE CHANCES OF PRECIPITATION WILL BE 18-01Z
SATURDAY. WE HAVE ACCOUNTED FOR THAT BY USING PROB30 IN THE
FORECASTS FOR LBF AND VTN 19-24Z.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JWS
SHORT TERM...JWS
LONG TERM...MASEK
AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
248 AM PDT SAT SEP 5 2015
.SYNOPSIS...A FEED OF TROPICAL MOISTURE INTO ARIZONA WILL STILL
ALLOW FOR A SHOWER OR THUNDERSTORM AROUND THROUGH TUESDAY. OTHERWISE
A STORM SYSTEM PASSING ACROSS NEVADA TODAY WILL RESULT IN ANOTHER
DAY OF GUSTY SOUTH TO SOUTHWEST WINDS ACROSS THE AREA ESPECIALLY IN
LINCOLN COUNTY. WINDS WILL DECREASE IN ALL AREAS ON SUNDAY.
TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH THE WEEKEND THEN
RETURN TO ABOVE NORMAL BY THE END OF NEXT WEEK.
&&
.SHORT TERM...TODAY THROUGH SUNDAY NIGHT.
A SOUTHWEST FLOW ALOFT WAS TRANSPORTING A FEED OF TROPICAL MOISTURE
NORTHEAST TOWARD ARIZONA THIS MORNING. THIS IS EVIDENT FROM
INSPECTING INFRARED SATELLITE IMAGERY AS ONE CAN SEE AN EXTENSIVE
AMOUNT OF CLOUDS ACROSS THE EASTERN TWO-THIRDS OF THE STATE. OUR
AREA WILL BE ON THE EDGE OF THIS MOISTURE FEED BUT WE NEVER REALLY
APPEAR TO SHAKE IT AWAY ALTOGETHER DESPITE AN APPROACHING MID/UPPER
LEVEL TROUGH WORKING INTO CALIFORNIA AND WESTERN NEVADA. AS A RESULT
ONCE AGAIN TODAY WE SHOULD STAND THE PROSPECT OF SEEING CUMULUS POP
UP IN EASTERN MOHAVE COUNTY AND POSSIBLY A SHOWER OR THUNDERSTORM
ESPECIALLY TOWARD THE MOUNT TRUMBULL AREA. THE HRRR STILL SHOWS SOME
WEAK RETURNS THIS AFTERNOON AS FAR WEST AS THE COLORADO RIVER BUT
THE DRIER AIR ADVANCING EAST ON WATER VAPOR RESULTS IN MY THOUGHT
THAT AT BEST THIS WOULD BE A FEW CUMULUS.
THERE IS STILL A BELT OF STRONGER WINDS ALOFT COURTESY OF THE JET
STREAM CROSSING THE EASTERN PARTS OF THE AREA TODAY. HOWEVER,
SEVERAL FACTORS DO NOT SUPPORT WINDS AS STRONG TODAY. THE SURFACE
PRESSURE GRADIENT IS VERY, VERY WEAK AND NOT EVEN ON PAR WITH WHAT
WE WOULD SEE ON A NORMAL DAY WITH JUST THERMALS. SECONDLY, THE 700
MB WINDS ON THE GFS AND ECMWF ARE MUCH LOWER TODAY - ABOUT 20 TO 25
KTS. AS A RESULT, I HAVE CANNED THE WIND ADVISORIES FOR NORTHEAST
CLARK AND NORTHERN MOHAVE COUNTY. IN LINCOLN COUNTY, THERE IS SOME
HOPE THAT WE MAY SEE A FEW POCKETS IN EASTERN AREAS REACH THE 40 MPH
GUST MARK FOR 3 HOURS SUCH AS PANACA SUMMIT, EAGLE VALLEY, SPRING
VALLEY STATE PARK AND BEAVER DAM. THUS THE WIND ADVISORY REMAINS IN
EFFECT THERE FOR LATE THIS MORNING THROUGH EARLY THIS EVENING.
TEMPS WILL DROP A FEW DEGREES TODAY BUT WE STILL LEANED TOWARD THE
WARMER END OF GUIDANCE FOR HIGHS. LOWS TONIGHT WERE TWEAKED UP A BIT
BASED ON A BLEND OF THE LATEST GUIDANCE BUT IT WILL STILL BE A
REFRESHING NIGHT AND START TO SUNDAY WITH LESS WIND. SOME OF THE
COLDER SPOTS IN LINCOLN COUNTY LIKE SPRING VALLEY STATE PARK AND
URSINE MAY DROP INTO THE 30S AS WILL THE HIGHER SPOTS IN THE SIERRA
AND WHITE MOUNTAINS AS WELL AS WELL UP ON MOUNT CHARLESTON. BE
PREPARED FOR THE CHILL IF YOU PLAN TO CAMP.
THE TROUGH AXIS WILL SORT OF GET HUNG UP ACROSS SOUTH-CENTRAL NEVADA
ON SUNDAY BEFORE DISSOLVING. AS A RESULT, MOHAVE COUNTY REMAINS IN
ENOUGH OF A SOUTHWEST FLOW TO ENTRAIN MOISTURE ON IN AND THE CHANCE
OF A SHOWER OR THUNDERSTORM WAS ADDED AGAIN INTO EASTERN AREAS FOR
SUNDAY. THE REST OF THE CWFA LOOKS DRY. TEMPS WILL START TO REBOUND
AND JUMP UP A DEGREE OR TWO. WITH LESS UPPER LEVEL SUPPORT WINDS
WILL ALSO BE LIGHTER. OVERALL FOR MOST AREAS THIS WILL BE THE PICK
OF THE LABOR DAY WEEKEND FOR THE BEST WEATHER. SUNDAY NIGHT`S LOWS
WERE RAISED UP AS WELL SEVERAL DEGREES BASED ON THE LATEST GUIDANCE.
ENJOY THIS LITTLE BREAK FROM THE INTENSITY OF SUMMER.
.LONG TERM...MONDAY THROUGH SATURDAY.
THE MEDIUM RANGE MODELS INDICATE A GENERALLY DRY PATTERN FOR MOST OF
THE FORECAST AREA WITH A WARMING TREND THE SECOND HALF OF THE WEEK.
THERE IS SOME UNCERTAINTY WITH MOISTURE FORECASTS BETWEEN THE GFS
AND ECMWF BUT NEITHER SOLUTION DEPICTS SIGNIFICANT MOISTURE
SPREADING INTO THE AREA. THE GFS CONTINUES TO INDICATE LOW TO MID
LEVEL MOISTURE LINGERING OVER NORTHWEST ARIZONA THROUGH LABOR DAY
AND IT IS WORTH MENTIONING A SLIGHT CHANCE OF THUNDERSTORMS OVER THE
EASTERN HALF OF MOHAVE COUNTY. AN INCREASINGLY DRY WESTERLY FLOW
DEVELOPING TUESDAY SHOULD PUSH MOST OF THE MOISTURE TO THE EAST
TUESDAY BUT A SLIGHT CHANCE OF THUNDERSTORMS STILL EXISTS FOR THE
ARIZONA STRIP.
WE WILL NEED TO KEEP AN EYE ON ANOTHER TROPICAL SYSTEM NEAR SOUTHERN
BAJA WHICH THE MODELS INDICATE WILL DEVELOP AND MOVE TO THE WEST
NORTHWEST THOUGH THERE IS LITTLE CHANCE OF ANY SIGNIFICANT MOISTURE
BEING PULLED OUR WAY. THE WARMING TREND WILL COME DUE TO AN EASTERN
PACIFIC RIDGE MERGING WITH A RIDGE NEAR NORTHERN MEXICO EXPANDING TO
THE NORTHWEST AFTER WEDNESDAY. THE ECMWF SOLUTION IS A LITTLE WARMER
THAN THE GFS AND PROVIDES HIGH TEMPS SEVERAL DEGREES ABOVE NORMAL
WITH TRIPLE DIGIT READINGS BACK OVER MUCH OF THE MOJAVE DESERT
REGION FROM WEDNESDAY INTO NEXT WEEKEND.
&&
.AVIATION...FOR MCCARRAN...WINDS WILL AGAIN INCREASE LATE THIS
MORNING AND BE STRONGEST IN THE AFTERNOON AND EARLY EVENING GUSTING
OVER 20 KTS. THERE IS A SMALL WINDOW BETWEEN 14Z AND 17Z TODAY WHERE
WIND DIRECTION WILL BE NEAR THE 160 DEGREE LINE WHICH MAY CAUSE
CONFIGURATION ISSUES.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...THERE WILL AGAIN BE THE POSSIBILITY OF A SHRA/TSRA
TODAY AFTER 18Z AND BEFORE 06Z SUNDAY IN AND AROUND MT TRUMBILL. ALL
OTHER AREAS SHOULD BE DRY. OTHERWISE LOOK FOR SOUTH TO SOUTHWEST
WINDS INCREASING BETWEEN 16Z AND 20Z TODAY WITH GUSTS OF 20-30 KTS
EXCEPT IN LINCOLN COUNTY WHERE GUSTS TO AROUND 35 KTS ARE POSSIBLE.
WINDS WILL SLOWLY DECREASE BETWEEN 03Z AND 06Z SUNDAY. A CLEAR SKY
IS EXPECTED EXCEPT IN AREAS EAST AND NORTHEAST OF KIGM WHERE FEW-SCT
CLOUDS AOA 10K-15K FEET WILL BE AROUND IN THE AFTERNOON AND EARLY
EVENING.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
SHORT TERM/AVIATION...STACHELSKI
LONG TERM...ADAIR
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS BISMARCK ND
131 AM CDT SAT SEP 5 2015
.UPDATE...
ISSUED AT 130 AM CDT SAT SEP 5 2015
STRONG S/WV IMPULSE LIFTING NORTH ACROSS THE WESTERN DAKOTAS.
LARGE AREA OF SHOWERS AND THUNDERSTORMS MOVING NORTH WITH THE WAVE
ACROSS EASTERN MT AND SOUTHWESTERN ND WILL CONTINUE TO DEVELOP
NORTH. HIGH RES MODELS THEN BRING ANOTHER WAVE NORTH LATER THIS
MORNING AND AFTERNOON. INCREASED POPS AND ALSO CLOUDY COVER WITH
LARGE AREA OF LOW STRATUS BUILDING SOUTHWARD AS WINDS BECOME MORE
NORTHEAST.
UPDATE ISSUED AT 941 PM CDT FRI SEP 4 2015
NEXT IMPULSE IN SOUTHWEST FLOW IS PRODUCING SHOWERS AND
THUNDERSTORMS FROM FAR SOUTHEAST MONTANA INTO NORTHEAST WYOMING.
THIS ACTIVITY IS TRACKING NORTHEAST AROUND 30-35 MPH AND SHOULD
BEGIN TO MOVE INTO SOUTHWEST NORTH DAKOTA IN THE NEXT FEW HOURS.
LATEST MESOSCALE MODELS SHOW THIS AREA LIFTING THROUGH WESTERN AND
INTO NORTH CENTRAL NORTH DAKOTA THROUGH THE OVERNIGHT HOURS.
UPDATED POP/WX GRIDS BASED ON A BLEND OF THE TIME-LAGGED HRRR AND
PERSISTENCE THROUGH 14 UTC. ALSO EXPANDED OVERCAST CLOUD COVER
ACROSS MAINLY THE NORTH HALF OF THE FORECAST AREA THIS EVENING AND
EXPANDED IT FARTHER SOUTH THROUGH THE OVERNIGHT HOURS.
UPDATE ISSUED AT 637 PM CDT FRI SEP 4 2015
EVEN IN THE SUBSIDENCE BEHIND THE EXITING SHORTWAVE THERE IS STILL
ENOUGH LOW LEVEL INSTABILITY FOR A FEW SHOWERS OR THUNDERSTORMS
OVER CENTRAL NORTH DAKOTA EARLY THIS EVENING. AN ISOLATED
THUNDERSTORM DEVELOPED OVER SHERIDAN COUNTY RECENTLY AS TWO
OUTFLOW BOUNDARIES COLLIDED. WILL KEEP A SLIGHT CHANCE FOR ANOTHER
COUPLE HOURS FROM JUST NORTHEAST OF BISMARCK UP INTO THE TURTLE
MOUNTAINS. LATEST MESOSCALE MODELS ARE SHOWING SHOWERS MOVING INTO
WESTERN NORTH DAKOTA LATER THAN PREVIOUSLY FORECAST. CURRENT
INDICATIONS SUGGEST MORE LIKE AROUND MIDNIGHT OR THEREAFTER. THUS
CUT BACK ON POPS IN THE FAR WEST THIS EVENING. CURRENT RADAR
ANALYSIS INDICATES SHOWER ACTIVITY IS CURRENTLY AROUND GLASGOW AND
FARTHER WEST.
UPDATE ISSUED AT 520 PM CDT FRI SEP 4 2015
QUICK UPDATE FOR POPS/SKY COVER AND TO FRESHEN LATEST SENSIBLE
WEATHER ELEMENTS. SHOWERS HAVE ALL BUT EXITED THE FAR EASTERN
CWA. WILL KEEP A SLIGHT CHANCE OVER FAR EASTERN STUTSMAN INTO
LAMOURE/DICKEY COUNTIES. OTHERWISE EXPECT DRY CONDITIONS INTO THIS
EVENING. CHANCES RETURN OUT WEST AGAIN LATE THIS EVENING.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 225 PM CDT FRI SEP 4 2015
SHOWER AND THUNDERSTORM POTENTIAL TONIGHT THROUGH SATURDAY
HIGHLIGHTS THE SHORT TERM FORECAST.
A BREAK IN PRECIPITATION IS EXPECTED ACROSS NEARLY ALL OF WESTERN
AND CENTRAL NORTH DAKOTA THIS AFTERNOON INTO THE EARLY EVENING
WITH SUBSIDENCE IN THE WAKE OF THE SHORTWAVE PROPAGATING INTO THE
NORTHEASTERN PORTIONS OF THE STATE. THE NEXT WAVE EVIDENT ON WATER
VAPOR IMAGERY ACROSS CENTRAL WYOMING THIS AFTERNOON WILL CONTINUE
TO PROPAGATE NORTHEAST THROUGH THE EVENING AND IMPACT WESTERN
NORTH DAKOTA LATE THIS EVENING AND THROUGH THE OVERNIGHT. AS A
RESULT... SCATTERED SHOWERS AND THUNDERSTORMS RETURN TO THE
FORECAST GENERALLY WEST OF HIGHWAY 83 WITH THIS FEATURE. SEVERE
WEATHER IS NOT EXPECTED. DURING THE DAY ON SATURDAY...RAINFALL IS
EXPECTED TO CONTINUE ACROSS THE NORTHWEST THROUGHOUT THE DAY WITH
MULTIPLE IMPULSES EMBEDDED IN SOUTHWEST FLOW ALOFT. WHILE
NORTHWEST NORTH DAKOTA IS IN THE DAY TWO EXCESSIVE RAINFALL
OUTLOOK...THIS HAS BEEN THE DRIEST PORTION OF THE STATE THIS
SUMMER AND DO NOT ANTICIPATE ANY FLOOD CONCERNS.
ELSEWHERE...EXPECT MORE SCATTERED...DIURNALLY DRIVEN CONVECTIVE
ACTIVITY THROUGH THE AFTERNOON AND EVENING. GIVEN GOOD
AGREEMENT...UTILIZED A BLEND OF THE 12 UTC DETERMINISTIC AND
ENSEMBLE SUITES.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 225 PM CDT FRI SEP 4 2015
COOLER TEMPERATURES HIGHLIGHT THE EXTENDED FORECAST.
THE 12 UTC DETERMINISTIC AND ENSEMBLE SUITES ARE IN GOOD AGREEMENT
ON THE LOW OVER NORTH CENTRAL MONTANA SATURDAY NIGHT PROPAGATING
INTO SASKATCHEWAN THROUGH THE DAY ON SUNDAY. THIS WOULD MARK THE
END OF PRECIPITATION FROM THE SHORT TERM BY SUNDAY MORNING AS
DRIER AIR OVERTAKES THE AREA. THEREAFTER...A MEAN...LOW AMPLITUDE
UPPER LEVEL TROUGH ACROSS THE CENTRAL CONUS FAVORS BELOW NORMAL
TEMPERATURES IN THE 60S AND 70S NEXT WEEK. GIVEN THESE COOLER
TEMPERATES...WILL HAVE TO MONITOR FROST POTENTIAL FOR NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 130 AM CDT SAT SEP 5 2015
IFR-VLIFR STRATUS AND PATCHY FOG DEVELOPING ACROSS ALL TERMINALS
EARLY THIS SATURDAY MORNING AND SHOULD PERSIST THROUGH THE AM
HOURS. SCATTERED SHOWERS AND THUNDERSTORMS ACROSS WESTERN NORTH
DAKOTA LATE TONIGHT INTO SATURDAY MORNING...WITH THIS ACTIVITY
THEN POSSIBLE CENTRAL INTO EAST LATER THIS MORNING AND INTO
SATURDAY AFTERNOON.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...AYD
LONG TERM...AYD
AVIATION...NH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1148 PM CDT FRI SEP 4 2015
.UPDATE...
ISSUED AT 1143 PM CDT FRI SEP 4 2015
MAINTAINED SOME LOW POPS ACROSS THE FAR EAST AS HRRR INDICATING
POSSIBLE REDEVELOPMENT OF SCT TSRA AS CURRENT RADAR INDICATING
SOME WEAK ECHOES DEVELOPING OVER WEST CENTRAL MN. ALSO EXPANDED
FOG MENTION ACROSS NORTHERN MN WHERE HEAVIER RAIN FELL.
UPDATE ISSUED AT 641 PM CDT FRI SEP 4 2015
MOST OF THE SCT SHRA/TSRA HAVE SHIFTED E INTO NW MN AS SHORT WAVE
CONTINUES TO LIFT NE. WILL TREND ENDING OF PCPN FROM SW-NE
GRADUALLY THROUGH THE EVENING WITH ANY LINGERING PCPN OVER THE NE
THIRD OF THE FA BY LATE EVENING. BASED ON CURRENT RADAR TRENDS
LIFTED SEVERE MENTION ACROSS FAR NW MN AS CURRENT CONVECTION HAS
SHOWN NO SIGNS OF INCREASING INTENSITY. NO OTHER SIGNIFICANT
CHANGES TO FORECAST.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 256 PM CDT FRI SEP 4 2015
WHAT HAPPENS WITH THE CONVECTION THIS EVENING AND ROUND TWO
TOMORROW WILL BE THE MAIN HEADACHE FOR THE PERIOD.
WV LOOP SHOWS A STRONG LEAD SHORTWAVE TROUGH CURRENTLY LIFTING
THROUGH EASTERN ND. CONVECTION FIRING ACROSS NORTHEASTERN NORTH
DAKOTA AHEAD OF THE SHORTWAVE HAS WEAKENED AFTER SOME CELLS PULSED
UP TO SEVERE. STILL PLENTY OF MOISTURE WITH DEWPOINTS IN THE UPPER
60S AND 70S...BUT CLOUDS HAVE LINGERED OVER THE AREA MUCH OF THE
DAY AND THE ATMOSPHERE IS WORKED OVER FROM PREVIOUS CONVECTION.
VIS SATELLITE SHOWS A BIT OF THINNING CLOUDS OVER THE CENTRAL
CWA...AND THE SPC MESOANALYSIS FINALLY HAS A BIT OF SFC BASED CAPE
AFTER THE EARLIER ELEVATED CONVECTION. THINK THERE WILL BE A
NARROW WINDOW OF OPPORTUNITY FOR REDEVELOPMENT IF THE NORTHERN CWA
CAN DESTABILIZE AS THE UPPER LOW LIFTS TO THE NORTH. EVEN
THEN...THE DEEP LAYER BULK SHEAR IS NOT VERY IMPRESSIVE...AROUND
30 KTS. SOME MARGINALLY SEVERE REDEVELOPMENT IS POSSIBLE INTO THE
EVENING...BUT THINK THAT MOST AREAS WILL JUST SEE HEAVY RAIN WITH
PWATS NEARING 2 INCHES.
TOMORROW...THE MAIN UPPER TROUGH WILL STILL BE OUT OF THE NORTHERN
ROCKIES...BUT MODELS BRING THROUGH ANOTHER LEAD SHORTWAVE AND THIS
SEEMS REASONABLE GIVEN A WEAK DISTURBANCE CURRENTLY SEEN OVER THE
DESERT SOUTHWEST. MODELS SEEM TO BE IN FAIRLY GOOD AGREEMENT ON A
BREAK IN PRECIP FOR SATURDAY MORNING...AND SOME LOW CLOUDS AND FOG
ARE NOT OUT OF THE QUESTION WITH RECENT RAINFALL. THE SHORTWAVE
TROUGH SHOULD BE COMING IN DURING THE AFTERNOON. SOME QUESTION AS
TO HOW MUCH WE WILL DESTABILIZE...BUT THE NAM AT LEAST HAS SOME
CAPE VALUES NEAR 2000 J/KG...ALTHOUGH THE 40 KTS BULK SHEAR ARE
WEST OF WHERE THE BEST CAPE IS EXPECTED. A STALLED FRONTAL
BOUNDARY OVER THE AREA COULD PROVIDE THE FOCUS FOR SOME
DEVELOPMENT. SOME MARGINALLY SEVERE STORMS WILL BE POSSIBLE BUT
IF THE SHORTWAVE COMES IN EARLIER THAN EXPECTED IT COULD
COMPLICATE THINGS. SOME FAIRLY GOOD QPF IS EXPECTED MAINLY OVER
OUR NORTHEASTERN COUNTIES LATER SATURDAY NIGHT AS THE SHORTWAVE
LIFTS THROUGH. TEMPS WILL BE HIGHLY DEPENDENT ON CLOUDS BUT FOR
NOW HAVE SOME 80S IN THE SOUTH AND 70S IN THE NORTHWEST BEHIND A
STALLED FRONT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 256 PM CDT FRI SEP 4 2015
SUNDAY AND MONDAY...THE UPPER TROUGH WILL LIFT FROM THE NORTHERN
ROCKIES AND INTO SOUTHERN CANADA...WITH ANOTHER LOBE OF THE TROUGH
DIGGING INTO MONTANA AND KEEPING THE NORTHERN PLAINS IN
SOUTHWESTERLY FLOW ALOFT. THE MAIN WAVE MOVING NORTHEAST SHOULD
HELP PUSH A FAIRLY STRONG COLD FRONT THROUGH THE CWA. MODELS VARY
ON HOW MUCH PRECIP OCCURS WITH THE FRONTAL PASSAGE...FOR NOW KEPT
BEST CHANCES IN THE NORTH AND EAST SUNDAY INTO SUNDAY NIGHT. TEMPS
SHOULD STILL BE IN THE 70S AND LOW 80S ON SUNDAY BUT GOOD COOL AIR
ADVECTION WILL HELP KEEP READINGS IN THE 70S FOR MONDAY.
FOR MONDAY NIGHT THROUGH FRIDAY...WILL BE STARTING OFF THE PERIOD
WITH A CLOSED LOW MOVING ACROSS CENTRAL CANADA. WILL SEE WEST-NW
WINDS AND COOL AFTERNOON HIGHS FOR TUE. FLOW BECOMES MORE ZONAL FOR
WED/WED NIGHT WHICH WILL PUSH ANOTHER FRONT THROUGH THE AREA. WILL
KEEP SOME LOW CHANCES FOR PCPN TO ACCOUNT FOR THIS. ONCE THIS FRONT
MOVES THRU THE FLOW TURNS BACK TO THE NORTHWEST FOR THU/FRI.
THEREFORE LOOKING FOR MAINLY DRY BUT COOL CONDITIONS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1143 PM CDT FRI SEP 4 2015
BY MORNING WILL LIKELY SEE BAND OF IFR STRATUS FROM BDE-TVF AND
GFK SOUTHEASTWARD WHICH SHOULD GRADUALLY BURN OFF IN THE AM. COULD
STILL SEE SOME OVERNIGHT TSRA OVER THE FAR EASTERN FA. NEXT T
POTENTIAL LOOKS LIKE LATER SATURDAY AFTERNOON.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...JR
LONG TERM...JR/GODON
AVIATION...VOELKER
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
425 AM EDT SAT SEP 5 2015
.SYNOPSIS...
THE UPPER LEVEL DISTURBANCE OVER MICHIGAN WILL WEAKEN AND LIFT
NORTHEAST TODAY. A BROAD AREA OF HIGH PRESSURE OVER NEW ENGLAND WILL
MOVE SOUTH ALONG THE EAST COAST THROUGH THE HOLIDAY WEEKEND. A
WEAKENING FRONT WILL STALL JUST NORTH OF THE AREA ON TUESDAY...THEN
PUSH SOUTH ON WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WATER VAPOR IMAGERY STILL SHOWS AN UPPER LEVEL CIRCULATION CENTERED
OVER SOUTHERN LAKE MICHIGAN EARLY THIS MORNING. A FEW THUNDERSTORMS
HAVE BEEN DEVELOPING EARLY THIS MORNING ACROSS INDIANA AND NW OHIO
AHEAD OF THE DRIER AIR WRAPPING AROUND THE SOUTH SIDE OF THE
CIRCULATION. THE RUC SHOWS THIS SPOKE OF ENERGY WILL TEND TO WEAKEN
OVER THE NEXT SEVERAL HOURS. AFTER THAT MODELS SHOWS THE UPPER LEVEL
FEATURE WEAKENING AND SLOWLY LIFTING NE ACROSS LOWER MICHIGAN
THROUGH THE AFTERNOON. EXPECT TO SEE THE EARLY MORNING CONVECTION IN
THE WEST TEND TO WEAKEN THROUGH 13-14Z THEN WAIT FOR INSTABILITY TO
INCREASE THIS AFTERNOON. COVERAGE OF SHOWERS AND THUNDERSTORMS IS
EXPECTED TO BE LESS THAN THE PAST COUPLE DAYS GIVEN THE WEAKENING
UPPER LEVEL FEATURE. SUFFICIENT INSTABILITY IS EXPECTED TO DEVELOP
AGAIN THIS AFTERNOON WITH POCKETS OF CAPE IN EXCESS OF 2000 J/KG.
THERE WILL BE LESS OF A TRIGGER THIS AFTERNOON WITH BEST CHANCES FOR
INITIATION IN NW OHIO ON THE SOUTHERN FLANK OF THE WAVE AND NE OHIO
ALONG THE LAKE BREEZE.
WITH LESS CLOUD COVER AND PRECIP THAN YESTERDAY...TEMPERATURES WILL
REBOUND INTO THE MID 80S IN PA TO NEAR 90 IN NW OHIO.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
THUNDERSTORMS WILL DIMINISH THIS EVENING WITH HEIGHTS BUILDING ALOFT
ON SUNDAY. THE TREND WILL CONTINUE FOR LESS THUNDERSTORM ACTIVITY
EXCEPT FOR NE OHIO/NW PA WHERE THUNDERSTORMS WILL LIKELY DEVELOP
AGAIN ALONG THE LAKE BREEZE. DEWPOINTS START TO MIX OUT BY MONDAY
AND EXPECT DRY CONDITIONS TO FINALLY PREVAIL WITH THE ATMOSPHERE
BECOMING INCREASINGLY CAPPED.
THE RIDGE ALOFT STARTS TO FLATTEN BY TUESDAY AS THE UPPER TROUGH
APPROACHES THE MIDWEST. GFS IS STILL MORE AGGRESSIVE WITH SHORTWAVE
ENERGY STREAMING NORTHEAST THROUGH THE CENTRAL GREAT LAKES ON
TUESDAY AFTERNOON AHEAD OF THE TROUGH WITH THUNDERSTORMS DEVELOPING.
THE GFS IS AN OUTLIER WITH THIS ENERGY AND OUTPACES THE RETURN OF
THE LOW-LEVEL MOISTURE. EXPECT CONVECTION TO FILL IN TUESDAY NIGHT
AS THE SLOW MOVING FRONTAL BOUNDARY SINKS SOUTH. GIVEN THE SLOWER
TIMING...KEPT HIGHS IN THE UPPER 80S TO NEAR 90 THROUGH TUESDAY.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
BOTH MODELS SIGNALING
CHANGE OF THE CURRENT WEATHER PATTERN MID WEEK. UNFORTUNATELY THE
ECMWF IS COMING INTO LINE WITH THE LATEST GFS. ALTHOUGH GFS A
LITTLE FASTER ON THE TIMING TREND IS STILL THE SAME. MODELS PUSH
COLD FRONT ACROSS THE FORECAST AREA ON WEDNESDAY ONLY TO STALL THE
FRONT ACROSS CENTRAL OHIO...WITH LOW PRESSURE MOVING ACROSS THE
LOWER LAKES BY THE END OF THE WORK WEEK. MEANWHILE AT THE UPPER
LEVELS NICE UPPER RIDGE WILL GRADUALLY BE REPLACED BY A DIGGING
TROUGH BY THIS TIME NEXT WEEK.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
LITTLE CHANGE IN WEATHER PATTERN. AREAS OF MVFR BR TOWARD
DAYBREAK WITH ISOLATED CONVECTION THIS AFTERNOON. DO NOT THINK
THERE WILL BE AS MUCH CONVECTION THIS AFTERNOON AS YDY.
OUTLOOK...AREAS OF NON VFR EACH MORNING IN FOG AND HAZE.
&&
.MARINE...
QUIET WEATHER WILL CONTINUE ON THE LAKE THROUGH THE
WEEKEND...ALTHOUGH A CHANCE OF THUNDERSTORM ACTIVITY IS POSSIBLE
THIS AFTERNOON. SOUTHWEST FLOW WILL DEVELOP ON THE LAKE EARLY IN
THE WORK WEEK AHEAD OF SLOW MOVING COLD FRONT. MODELS CONTINUE TO
HOLD OFF THE NEXT FRONT UNTIL WEDNESDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KEC
NEAR TERM...KEC
SHORT TERM...KEC
LONG TERM...DJB
AVIATION...DJB
MARINE...DJB
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
504 AM EDT SAT SEP 5 2015
.SYNOPSIS...
HIGH PRESSURE WILL ENSURE MAINLY DRY WEATHER FOR LABOR DAY
WEEKEND WITH ABOVE NORMAL WARMTH AND JUST THE CHANCE OF AN
AFTERNOON OR EVENING POP-UP SHOWER OR THUNDERSTORM. THE PATTERN
WILL START TO CHANGE IN THE MIDDLE OF THE WEEK AS THE UPPER LEVEL
FLOW FLATTENS OUT AND A COLD FRONT DROPS DOWN FROM THE NORTH.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SHOWERS HAVE BEEN PERSISTENT IN THE SRN TIER THROUGH THE NIGHT.
THE WIND SHIFT/WEAK CONVERGENCE AND DEEP EASTERLY MOISTURE INFLUX
ARE PROBABLY DRIVING THESE SHOWERS SINCE DIURNAL INSTABILITY HAS
LONG SINCE DISAPPEARED. ONLY LIGHT SHOWERS /NO T/ LEFT IN THE SC
MTNS. HRRR AND RAP MOVE THESE SLIGHTLY TO THE WEST BEFORE KILLING
THEM OFF JUST AFTER SUNRISE. LOW CLOUDS HAVE OVERSPREAD/DEVELOPED
OVER THE ENTIRE REGION EXCEPT FOR WARREN CO. A FEW PATCHES OF
CLEAR EAST OF KIPT CAN BE IMAGINED WHEN PERUSING THE 11-3.9
MICRON IMAGERY THIS MORNING. OTHERWISE...IT IS CLOUDY. THESE
CLOUDS COULD BE TOUGH TO MIX OUT - AT LEAST IN A RAPID FASHION -
SINCE THEY ARE GENERALLY ABOVE 1KFT. THUS...WILL HANG ONTO SOME OF
THESE CLOUDS INTO THE MID TO LATE MORNING. THE EAST WILL BE
BREAKING OUT INTO THE SUN AND THE MIXING IN THE WEST COULD ALLOW A
SHOWER OR TWO TO DEVELOP IN THE AFTN. HOWEVER...MOST OF THESE WILL
REMAIN WEST OF THE CWA. ONLY THE NW IS WORTHY OF A CHC POP FOR
LATE THIS AFTN/THIS EVENING AS A LAKE BREEZE MAY KICK OFF A FEW
SHRA. THE CLOUDS WILL MAKE IT MORE DIFFICULT TO GET TO THE LOFTY
MAXES WE HAVE EXPERIENCED RECENTLY - INCLUDING TIES OF THE RECORD
HIGHS AT HARRISBURG...ALTOONA AND BRADFORD YESTERDAY. WILL GO FOR
MAXES BASED ON AN EQUAL BLEND OF MOS GUIDANCE MINUS ONE OR TWO
DEGS. THIS WILL RESULT IN ONLY A 10 DEGREE DIURNAL SWING AT MANY
PLACES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
THE UPPER LOW OVER THE UPPER GREAT LAKES WILL SLOLY FILL AND LOSE
CHARACTER. THE SFC HIGH WILL STILL NOSE INTO THE STATE...BUT THE
CENTER OF IT WILL SLIDE SOUTH INTO THE WESTERN ATLANTIC BY
MONDAY. ANY SHOWERS THIS EVENING WILL LIKELY BE IN THE NW...BUT
THE EXPECTED CELL MOTION SHOULD KEEP THEM EITHER OUT OF THE STATE
TO THE NORTH OR MAKE THE FEW THAT DO POP UP GO SLOWLY TO THE NORTH
AND OUT OF THE AREA EARLY THIS EVENING. THE LOW CLOUDS WILL
PROBABLY TRY TO REDEVELOP IN THE ERN MTNS. OTHER AREAS MAY SEE
THEM TRY TO FORM...BUT WILL KEEP IT GENERALLY P/C OVERNIGHT WITH
THE CLEARING PERHAPS ALLOWING FOR SOME MORNING FOG ON SUNDAY.
SUNDAY LOOKS TO BE DRIER AND SUNNIER...AND POPS ALMOST NON-
EXISTENT. TEMPS WILL GET A FEW DEGS F WARMER VS SATURDAY. ONCE
AGAIN...IT WILL BE THE FAR NW WHICH COULD SEE A POP UP SHOWER -
PERHAPS AGAIN BEING GENERATED ALONG A LAKE BREEZE BOUNDARY.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
THE HIGH PRESSURE WILL KEEP IT WARM AND MAINLY DRY INTO MONDAY.
A WEAK COLD FRONT WILL SLIDE SLOWLY TO THE ESE FROM THE GREAT
LAKES/MIDWEST STATES. THIS FEATURE COULD BRING SOME ISOLATED
SHRA/TSRA TO OUR NW ZONES BEGINNING TUESDAY AFTERNOON AND EVENING.
A SLOWLY AMPLIFYING BROAD TROUGH FROM THE NRN PLAINS THROUGH THE
NE U.S. WEDNESDAY AFTERNOON INTO NEXT WEEKEND WILL PUSH A
SECOND...STRONGER CFRONT EAST ACROSS THE COMMONWEALTH WEDNESDAY
NIGHT AND THURSDAY.
THIS PATTERN TRANSITION WILL BRING A FEW OPPORTUNITIES FOR
SHOWERS AND THUNDERSTORMS...ALBEIT MAINLY OF THE SCATTERED
AFTERNOON AND EVENING VARIETY.
12Z GEFS AND 12Z EC ARE IN GOOD AGREEMENT ON THE LOCATION OF THIS
TROUGH AXIS /FROM LAKE SUPERIOR TO THE MID MISS VALLEY AT 00Z
SAT/...THOUGH AS ONE WOULD EXPECT...THE ENSEMBLE MEAN DAMPENS OUT
THE AMPLITUDE OF THE TROUGH COMPARED TO THE EC.
DETAILS IN THE TIMING OF ANY SPECIFIC SHORTWAVES ROTATING THROUGH
THIS AMPLIFYING TROUGH ARE SIMPLY TOO MUDDY AT THIS TIME RANGE.
ONE THING MORE CERTAIN IN THIS MEDIUM RANGE FORECAST IS THE COOLING
TEMPS FOR THE LATTER HALF OF THE WEEK AND NEXT WEEKEND...WHEN BOTH
MAX AND MIN TEMPS COULD BE UP TO SEVERAL DEG F BELOW NORMAL
/ESPECIALLY OVER THE NRN AND WESTERN MTNS OF THE STATE...WHERE MORE
CLOUDS AND COOLER TEMPS ALOFT WILL BE FOUND/.
&&
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
11.3.9U IMAGERY AT 09Z SHOWS STRATUS HAS BECOME WIDESPREAD ACROSS
CENTRAL PA...THE RESULT OF MOIST SERLY FLOW AND OROGRAPHIC
LIFTING. BLEND OF LATEST HRRR/SFC OBS SUGGEST IFR CIGS ARE LIKELY
BTWN 09Z-13Z AT KBFD/KJST/KAOO AND POSSIBLE AT KUNV. LOWER
ELEVATIONS FURTHER EAST SHOULD FARE BETTER WITH MVFR CIGS
EXPECTED. WILL HAVE TO WATCH FOR POSSIBILITY OF FOG DEVELOPMENT AT
KLNS ARND DAWN. SOME MDL DATA SUGGESTS SKIES WILL CLEAR ACROSS
THAT PART OF THE STATE ARND 10Z...ALLOWING FOR DEVELOPMENT OF
RADIATION FOG BTWN 10Z-13Z.
DIURNAL HEATING/MIXING WILL CAUSE CIGS TO RISE BY LATE AM. MDL
SOUNDINGS INDICATE MVFR CIGS MAY LINGER ACROSS THE CENTRAL MTNS
UNTIL ARND NOON. HOWEVER...BY AFTN THERE IS A HIGH DEGREE OF
CONFIDENCE IN WIDESPREAD VFR CONDS AND LIGHT WIND.
MOSTLY CLEAR SKIES AND A LIGHT WIND WILL LIKELY RESULT IN PATCHY
VALLEY FOG AGAIN EARLY SUNDAY MORNING.
OUTLOOK...
SUN-TUE...PATCHY FOG IN THE MORNING...OTHERWISE VFR.
WED...ISOLD PM TSRA IMPACTS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...LAMBERT
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
452 AM EDT SAT SEP 5 2015
.SYNOPSIS...
HIGH PRESSURE WILL ENSURE MAINLY DRY WEATHER FOR LABOR DAY
WEEKEND WITH ABOVE NORMAL WARMTH AND JUST THE CHANCE OF AN
AFTERNOON OR EVENING POP-UP SHOWER OR THUNDERSTORM. THE PATTERN
WILL START TO CHANGE IN THE MIDDLE OF THE WEEK AS THE UPPER LEVEL
FLOW FLATTENS OUT AND A COLD FRONT DROPS DOWN FROM THE NORTH.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SHOWERS HAVE BEEN PERSISTENT IN THE SRN TIER THROUGH THE NIGHT.
THE WIND SHIFT/WEAK CONVERGENCE AND DEEP EASTERLY MOISTURE INFLUX
ARE PROBABLY DRIVING THESE SHOWERS SINCE DIURNAL INSTABILITY HAS
LONG SINCE DISAPPEARED. ONLY LIGHT SHOWERS /NO T/ LEFT IN THE SC
MTNS. HRRR AND RAP MOVE THESE SLIGHTLY TO THE WEST BEFORE KILLING
THEM OFF JUST AFTER SUNRISE. LOW CLOUDS HAVE OVERSPREAD/DEVELOPED
OVER THE ENTIRE REGION EXCEPT FOR WARREN CO. A FEW PATCHES OF
CLEAR EAST OF KIPT CAN BE IMAGINED WHEN PERUSING THE 11-3.9
MICRON IMAGERY THIS MORNING. OTHERWISE...IT IS CLOUDY. THESE
CLOUDS COULD BE TOUGH TO MIX OUT - AT LEAST IN A RAPID FASHION -
SINCE THEY ARE GENERALLY ABOVE 1KFT. THUS...WILL HANG ONTO SOME OF
THESE CLOUDS INTO THE MID TO LATE MORNING. THE EAST WILL BE
BREAKING OUT INTO THE SUN AND THE MIXING IN THE WEST COULD ALLOW A
SHOWER OR TWO TO DEVELOP IN THE AFTN. HOWEVER...MOST OF THESE WILL
REMAIN WEST OF THE CWA. ONLY THE NW IS WORTHY OF A CHC POP FOR
LATE THIS AFTN/THIS EVENING AS A LAKE BREEZE MAY KICK OFF A FEW
SHRA. THE CLOUDS WILL MAKE IT MORE DIFFICULT TO GET TO THE LOFTY
MAXES WE HAVE EXPERIENCED RECENTLY - INCLUDING TIES OF THE RECORD
HIGHS AT HARRISBURG...ALTOONA AND BRADFORD YESTERDAY. WILL GO FOR
MAXES BASED ON AN EQUAL BLEND OF MOS GUIDANCE MINUS ONE OR TWO
DEGS. THIS WILL RESULT IN ONLY A 10 DEGREE DIURNAL SWING AT MANY
PLACES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
THE UPPER LOW OVER THE UPPER GREAT LAKES WILL SLOLY FILL AND LOSE
CHARACTER. THE SFC HIGH WILL STILL NOSE INTO THE STATE...BUT THE
CENTER OF IT WILL SLIDE SOUTH INTO THE WESTERN ATLANTIC BY
MONDAY. ANY SHOWERS THIS EVENING WILL LIKELY BE IN THE NW...BUT
THE EXPECTED CELL MOTION SHOULD KEEP THEM EITHER OUT OF THE STATE
TO THE NORTH OR MAKE THE FEW THAT DO POP UP GO SLOWLY TO THE NORTH
AND OUT OF THE AREA EARLY THIS EVENING. THE LOW CLOUDS WILL
PROBABLY TRY TO REDEVELOP IN THE ERN MTNS. OTHER AREAS MAY SEE
THEM TRY TO FORM...BUT WILL KEEP IT GENERALLY P/C OVERNIGHT WITH
THE CLEARING PERHAPS ALLOWING FOR SOME MORNING FOG ON SUNDAY.
SUNDAY LOOKS TO BE DRIER AND SUNNIER...AND POPS ALMOST NON-
EXISTENT. TEMPS WILL GET A FEW DEGS F WARMER VS SATURDAY. ONCE
AGAIN...IT WILL BE THE FAR NW WHICH COULD SEE A POP UP SHOWER -
PERHAPS AGAIN BEING GENERATED ALONG A LAKE BREEZE BOUNDARY.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
THE HIGH PRESSURE WILL KEEP IT WARM AND MAINLY DRY INTO MONDAY.
A WEAK COLD FRONT WILL SLIDE SLOWLY TO THE ESE FROM THE GREAT
LAKES/MIDWEST STATES. THIS FEATURE COULD BRING SOME ISOLATED
SHRA/TSRA TO OUR NW ZONES BEGINNING TUESDAY AFTERNOON AND EVENING.
A SLOWLY AMPLIFYING BROAD TROUGH FROM THE NRN PLAINS THROUGH THE
NE U.S. WEDNESDAY AFTERNOON INTO NEXT WEEKEND WILL PUSH A
SECOND...STRONGER CFRONT EAST ACROSS THE COMMONWEALTH WEDNESDAY
NIGHT AND THURSDAY.
THIS PATTERN TRANSITION WILL BRING A FEW OPPORTUNITIES FOR
SHOWERS AND THUNDERSTORMS...ALBEIT MAINLY OF THE SCATTERED
AFTERNOON AND EVENING VARIETY.
12Z GEFS AND 12Z EC ARE IN GOOD AGREEMENT ON THE LOCATION OF THIS
TROUGH AXIS /FROM LAKE SUPERIOR TO THE MID MISS VALLEY AT 00Z
SAT/...THOUGH AS ONE WOULD EXPECT...THE ENSEMBLE MEAN DAMPENS OUT
THE AMPLITUDE OF THE TROUGH COMPARED TO THE EC.
DETAILS IN THE TIMING OF ANY SPECIFIC SHORTWAVES ROTATING THROUGH
THIS AMPLIFYING TROUGH ARE SIMPLY TOO MUDDY AT THIS TIME RANGE.
ONE THING MORE CERTAIN IN THIS MEDIUM RANGE FORECAST IS THE COOLING
TEMPS FOR THE LATTER HALF OF THE WEEK AND NEXT WEEKEND...WHEN BOTH
MAX AND MIN TEMPS COULD BE UP TO SEVERAL DEG F BELOW NORMAL
/ESPECIALLY OVER THE NRN AND WESTERN MTNS OF THE STATE...WHERE MORE
CLOUDS AND COOLER TEMPS ALOFT WILL BE FOUND/.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
ISOLD SHRA CONTINUE TO FIRE EARLY THIS AM ALONG DYING COLD FRONT
OVER SOUTH CENTRAL PA. LATEST HRRR SUGGESTS A BRIEF SHOWER WILL
REMAIN POSSIBLE THRU ARND 12Z FROM KUNV SOUTHWARD THRU KAOO AND
KJST. HOWEVER...THE MAIN CONCERN EARLY THIS MORNING WILL BE
DEVELOPING LOW CIGS...RESULTING FROM MOIST SERLY FLOW ASCENDING
THE MTNS OF CENTRAL PA. BLEND OF LATEST HRRR/LAMP SUGGEST IFR CIGS
ARE LIKELY AFTER 09Z AT KBFD/KJST AND POSSIBLE AT KAOO/KUNV. LOWER
ELEVATIONS FURTHER EAST SHOULD FARE BETTER WITH MVFR CIGS
EXPECTED. WILL HAVE TO WATCH FOR POSSIBILITY OF FOG DEVELOPMENT AT
KLNS ARND DAWN. SOME OF THE LATEST MDL DATA SUGGESTS SKIES WILL
CLEAR ACROSS THAT PART OF THE STATE ARND 10Z...ALLOWING FOR
DEVELOPMENT OF RADIATION FOG BTWN 10Z-13Z.
DIURNAL HEATING/MIXING WILL CAUSE CIGS TO RISE BY LATE AM. MDL
SOUNDINGS INDICATE MVFR CIGS MAY LINGER ACROSS THE CENTRAL MTNS
UNTIL ARND NOON. HOWEVER...BY AFTN THERE IS A HIGH DEGREE OF
CONFIDENCE IN WIDESPREAD VFR CONDS AND LIGHT WIND.
MOSTLY CLEAR SKIES AND A LIGHT WIND WILL LIKELY RESULT IN PATCHY
VALLEY FOG AGAIN EARLY SUNDAY MORNING.
OUTLOOK...
SUN-TUE...PATCHY FOG IN THE MORNING...OTHERWISE VFR.
WED...COLD FROPA WITH SCT SHRA/TSRA.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...LAMBERT
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
217 AM EDT SAT SEP 5 2015
.SYNOPSIS...
HIGH PRESSURE WILL ENSURE FAIR AND MAINLY DRY WEATHER FOR LABOR
DAY WEEKEND WITH ABOVE NORMAL WARMTH AND JUST THE CHANCE OF AN
AFTERNOON OR EVENING POP-UP SHOWER OR THUNDERSTORM.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS THE SURFACE AND UPPER LEVEL HIGH SLIDES SOUTH ALONG THE NEW
ENGLAND COAST...IT IS FORCING A DEEP EASTERLY FLOW INTO THE AREA.
WEAK LOCAL FORCING...RESIDUAL INSTABILITY AND A GENERAL UPSLOPE
COMPONENT TO THE LOW LEVEL FLOW ARE ALL COMBINING TO KEEP SOME
SCATTERED SHOWERS AND THUNDERSTORMS FLOATING AROUND IN A RATHER
DISORGANIZED FASHION AS OF LATE EVENING.
THE HRRR KEEPS TRYING TO ORGANIZE A SMALL MCS WHICH IT TRACKS
THROUGH THE SOUTH CENTRAL MOUNTAINS BETWEEN ABOUT 5 AND 11Z. THIS
SEEMS OVERDONE AND WILL MORE LIKELY BE ISOLATED LEFT OVER
ACTIVITY... GIVEN THE NEGATIVE TREND IN OBSERVED CAPE AND THE
NORMAL DIURNAL DIE OFF TIME...AND EVEN COULD BE PORTRAYING AN
INCREASE IN LOW CLOUDS/MOISTURE THAT SHOULD START ADVECTING WEST
IN THE MARITIME FLOW.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SUNDAY/...
FOR SATURDAY MODEL MID LEVEL TEMPS ARE EXPECTED TO INCREASE TO
VALUES CLOSER TO WHAT WE NORMALLY SEE ACT AS AN EFFECTIVE CAP IN
THE LOCAL AREA. BETWEEN THAT AND MORE IN THE WAY OF LOW
CLOUDINESS...WE SHOULD BE COOLER IN THE LOW LEVELS AND WARMER
ALOFT WHICH WILL EQUATE TO LESS INSTABILITY AND A SMALLER CHANCE FOR
SHOWERS. THE BEST CHANCE FOR AN ISOLATED STORM WILL BE OVER
WESTERN AREAS DURING THE LATTER HALF OF THE DAY.
HIGHS WILL BE A FEW DEGREES COOLER THAN PREVIOUS DAYS AND
DEWPOINTS WILL EVEN NUDGE DOWN A BIT AS LOWER DEWPOINTS START TO
ADVECT IN FORM THE NORTHEAST.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
A RATHER LARGE AREA OF HIGH PRESSURE AT THE SFC...AND A SLOWLY
FLATTENING UPPER RIDGE OVER THE EASTERN U.S...SHOULD MAINTAIN DRY
WEATHER SATURDAY NIGHT THROUGH MONDAY. PRECIPITABLE WATER VALUES
WILL RANGE FROM BELOW NORMAL AND ONLY AROUND ONE-HALF OF AN INCH
ACROSS FAR NERN PENN...TO SLIGHTLY ABOVE NORMAL ALONG THE SE SHORE
OF LAKE ERIE SUNDAY SATURDAY NIGHT INTO SUNDAY NIGHT. A FEW SHOWERS
OR EVEN A BRIEF TSRA COULD BRUSH OUR FAR NW ZONES DURING THIS
INITIAL 24 HOURS OF THE LONG TERM PERIOD...BUT POPS WILL BE LESS
THAN 25 PERCENT.
AN INITIAL...WEAK...COLD FRONT WILL SLIDE SLOWLY TO THE ESE FROM THE
GREAT LAKES/MIDWEST STATES. THIS FEATURE COULD BRING SOME ISOLATED
SHRA/TSRA TO OUR NW ZONES BEGINNING TUESDAY AFTERNOON AND EVENING.
A SLOWLY AMPLIFYING...BROAD TROUGH FROM THE NRN PLAINS THROUGH THE
NE U.S. WEDNESDAY AFTERNOON INTO NEXT WEEKEND WILL PUSH A
SECOND...STRONGER CFRONT EAST ACROSS THE COMMONWEALTH WEDNESDAY
NIGHT AND THURSDAY.
THIS PATTERN TRANSITION WILL BRING A FEW OPPORTUNITIES FOR
SHOWERS AND THUNDERSTORMS...ALBEIT MAINLY OF THE SCATTERED
AFTERNOON AND EVENING VARIETY.
12Z GEFS AND 12Z EC ARE IN GOOD AGREEMENT ON THE LOCATION OF THIS
TROUGH AXIS /FROM LAKE SUPERIOR TO THE MID MISS VALLEY AT 00Z
SAT/...THOUGH AS ONE WOULD EXPECT...THE ENSEMBLE MEAN DAMPENS OUT
THE AMPLITUDE OF THE TROUGH COMPARED TO THE EC.
DETAILS IN THE TIMING OF ANY SPECIFIC SHORTWAVES ROTATING THROUGH
THIS AMPLIFYING TROUGH ARE SIMPLY TOO MUDDY AT THIS TIME RANGE.
ONE THING MORE CERTAIN IN THIS MEDIUM RANGE FORECAST IS THE COOLING
TEMPS FOR THE LATTER HALF OF THE WEEK AND NEXT WEEKEND...WHEN BOTH
MAX AND MIN TEMPS COULD BE UP TO SEVERAL DEG F BELOW NORMAL
/ESPECIALLY OVER THE NRN AND WESTERN MTNS OF THE STATE...WHERE MORE
CLOUDS AND COOLER TEMPS ALOFT WILL BE FOUND/.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
ISOLD SHRA CONTINUE TO FIRE EARLY THIS AM ALONG DYING COLD FRONT
OVER SOUTH CENTRAL PA. LATEST HRRR SUGGESTS A BRIEF SHOWER WILL
REMAIN POSSIBLE THRU ARND 12Z FROM KUNV SOUTHWARD THRU KAOO AND
KJST. HOWEVER...THE MAIN CONCERN EARLY THIS MORNING WILL BE
DEVELOPING LOW CIGS...RESULTING FROM MOIST SERLY FLOW ASCENDING
THE MTNS OF CENTRAL PA. BLEND OF LATEST HRRR/LAMP SUGGEST IFR CIGS
ARE LIKELY AFTER 09Z AT KBFD/KJST AND POSSIBLE AT KAOO/KUNV. LOWER
ELEVATIONS FURTHER EAST SHOULD FARE BETTER WITH MVFR CIGS
EXPECTED. WILL HAVE TO WATCH FOR POSSIBILITY OF FOG DEVELOPMENT AT
KLNS ARND DAWN. SOME OF THE LATEST MDL DATA SUGGESTS SKIES WILL
CLEAR ACROSS THAT PART OF THE STATE ARND 10Z...ALLOWING FOR
DEVELOPMENT OF RADIATION FOG BTWN 10Z-13Z.
DIURNAL HEATING/MIXING WILL CAUSE CIGS TO RISE BY LATE AM. MDL
SOUNDINGS INDICATE MVFR CIGS MAY LINGER ACROSS THE CENTRAL MTNS
UNTIL ARND NOON. HOWEVER...BY AFTN THERE IS A HIGH DEGREE OF
CONFIDENCE IN WIDESPREAD VFR CONDS AND LIGHT WIND.
MOSTLY CLEAR SKIES AND A LIGHT WIND WILL LIKELY RESULT IN PATCHY
VALLEY FOG AGAIN EARLY SUNDAY MORNING.
OUTLOOK...
SUN-TUE...PATCHY FOG IN THE MORNING...OTHERWISE VFR.
WED...COLD FROPA WITH SCT SHRA/TSRA.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...DANGELO/GARTNER
LONG TERM...LAMBERT
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
345 AM CDT SAT SEP 5 2015
.SHORT TERM (TODAY THROUGH SUNDAY)...UPPER LEVEL RIDGE WILL
BUILD OVER SOUTH TEXAS TODAY INTO SUNDAY. MOISTURE WILL BE A
LITTLE LESS TODAY AS MODELS PROG PW VALUES BETWEEN 1.7 TO 1.9
INCHES. ISOLATED CONVECTION OVER THE MARINE WATERS MAY APPROACH
THE COAST LATER THIS MORNING. THEN...DAYTIME HEATING COMBINED WITH
THE SEA BREEZE MAY BE ENOUGH TO GENERATE ISOLATED TO POSSIBLY
SCATTERED SHOWERS AND A FEW STORMS. LAST FEW RUNS OF THE HRRR AT
LEAST SUPPORT THIS TO SOME EXTENT...AND HAVE KEPT 20 POPS ACROSS
THE EAST WITH SOME 30 POPS ACROSS THE VICTORIA CROSSROADS.
CONDITIONS SHOULD BE A LITTLE WARMER TODAY COMPARED TO YESTERDAY
AS HIGHS CLIMB INTO THE LOWER 100S OUT WEST...TO MID/LOWER 90S
ACROSS THE EAST AND NORTHEAST. MOISTURE DECREASES A LITTLE MORE ON
SUNDAY AND GUIDANCE IS NOT TOO OPTIMISTIC ABOUT RAIN CHANCES. WILL
LEAVE RAIN CHANCES OUT OF THE FORECAST FOR NOW. ABOVE NORMAL
TEMPERATURES WILL CONTINUE ON SUNDAY.
&&
.LONG TERM (SUNDAY NIGHT THROUGH FRIDAY)...CHANGES IN THE UPPER
PATTERN TAKE PLACE BY SUNDAY NIGHT WITH H5 RIDGE FLATTENS AND SLIDES
WEST AS A TROUGH SWINGS EAST ACROSS THE HIGH PLAINS AND A WEAK CUT
OFF LOW DRIFTS WEST ALONG ACROSS THE GULF STATES INTO THE WESTERN
GULF. MODELS DISAGREE ON THE AMOUNT OF MOISTURE AVAILABLE...BUT
OVERALL...A RELATIVE INCREASE IN MOISTURE MOVES INTO THE WESTERN
GULF AS WELL AS THE EASTERN HALF OF THE CWA...AND IS DRAWN NORTH
INTO THE CENTRAL PLAINS. WITH WEAKNESS ALOFT AND SLIGHTLY COOL H85-
H7 TEMPS...DAILY CONVECTION IS EXPECTED THROUGH THE WEEK IN THE FORM
OF SHOWERS IN THE MORNING ACROSS THE GULF...MOVING INLAND WITH
HEATING. THE GFS AND EURO BOTH HINT AT A SURFACE FRONT TO MOVE
THROUGH THE CENTRAL PLAINS AND PUSH SOUTH INTO TEXAS. DISAGREEMENTS
DEVELOP BETWEEN THE LONG TERM MODELS ON THE DEVELOPMENT AND TIMING
OF THE FRONT FROM THURSDAY AND ONWARD. THIS SAID...MAINLY KEPT
SLIGHT CHANCE POPS FROM MONDAY THROUGH WEDNESDAY FOR ISOLATED
ACTIVITY ACROSS THE NORTHERN COASTAL BEND AND COASTAL PLAINS...WITH
20-30 POPS INTRODUCED BY FRIDAY DUE TO PROXIMITY OF THE BOUNDARY.
TEMPERATURES FOR THE MOST PART WILL BE SLIGHTLY ABOVE NORMAL THROUGH
MUCH OF THE WEEK...WITH COOLER TEMPS TOWARD THE LATER OF THE WORK
WEEK MAINLY DUE TO THE INCREASED CLOUD COVERAGE AND RAIN CHANCES.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 94 79 94 77 94 / 20 10 10 10 20
VICTORIA 94 76 96 75 95 / 30 10 10 10 20
LAREDO 102 79 102 77 102 / 10 10 0 0 10
ALICE 97 76 98 75 98 / 20 10 10 10 10
ROCKPORT 91 80 91 79 90 / 30 10 10 10 20
COTULLA 101 77 101 75 102 / 10 10 0 0 10
KINGSVILLE 96 78 97 76 97 / 20 10 10 10 10
NAVY CORPUS 90 80 90 80 90 / 20 10 10 10 20
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
TB/78...SHORT TERM
CB/85...LONG TERM
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
427 AM EDT SAT SEP 5 2015
.SYNOPSIS...
A BACKDOOR COLD FRONT WILL DRIFT INTO FAR SOUTHWEST VIRGINIA AND
NORTHWEST NORTH CAROLINA BY EVENING AND STALL AS SURFACE HIGH
PRESSURE BUILDS SOUTHWESTWARD FROM THE NORTHERN MID-
ATLANTIC...ALLOWING FOR COOLER CONDITIONS TODAY AND CONFINING
THUNDERSTORMS TO WESTERN AREAS. LOW PRESSURE ALOFT WILL LINGER
ACROSS THE SOUTHEAST STATES OVER THE NEXT SEVERAL DAYS ALLOWING
WARM AND HUMID CONDITIONS ALONG WITH SCATTERED SHOWERS AND
THUNDERSTORMS TO RETURN TO THE ENTIRE AREA BY EARLY NEXT WEEK. A
STRONGER COLD FRONT WILL ARRIVE LATE NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 415 AM EDT SATURDAY...
A CONVECTIVE OUTFLOW BOUNDARY FROM FRIDAY EVENING WIDESPREAD
THUNDERSTORM ACTIVITY APPEARS TO BE IN PLACE ACROSS FAR SOUTHWEST
VA/EASTERN TN/WESTERN NC...BUT THE TRUE BACKDOOR FRONT IS EVIDENT
JUST EAST OF THE BLUE RIDGE. NEAR THIS BACKDOOR FRONTAL
BOUNDARY...SPOTTY SHOWERS HAVE CONTINUED TO DEVELOP THROUGHOUT THE
NIGHT. HRRR AND LOCAL WRF MODELS SUPPORT A CONTINUATION OF THIS
PATTERN INTO THE MORNING...SHIFTING FURTHER WEST BY AFTERNOON. AT
THAT POINT...SUFFICIENT INSTABILITY WILL BE PRESENT FOR MORE
THUNDERSTORMS. CURRENT THINKING IS THAT A MORE STABLE AIR MASS
WILL SPREAD ACROSS THE PIEDMONT AND TOWARD THE ALLEGHANY FRONT BY
AFTERNOON...CONFINING THUNDERSTORMS TO THE I-77 CORRIDOR AND
POINTS WEST.
WITH A HEALTHY MARITIME EASTERLY FLOW DEVELOPING ACROSS AREAS
EAST OF THE ALLEGHANY FRONT IN THE WAKE OF THE BACKDOOR
FRONT...WIDESPREAD LOW CLOUDS ARE EXPECTED TO DEVELOP AND PERSIST
THROUGH MUCH OF THE DAY. THIS IS ALREADY EVIDENT ON THE LATEST
SATELLITE IMAGES. THESE CLOUDS WILL RESULT IN CONSIDERABLY COOLER
TEMPERATURES THAN WE HAVE SEEN IN RECENT DAYS ACROSS EASTERN PARTS
OF THE CWA...ESPECIALLY THE PIEDMONT WITH MAX AFTERNOON
TEMPERATURES STRUGGLING TO RISE OUT OF THE 70S...SOME 10-15
DEGREES COOLER THAN THE LAST SEVERAL DAYS. WEST OF THE I-77
CORRIDOR...TEMPERATURES ARE STILL EXPECTED TO BE QUITE WARM AND
NEAR TO ABOVE NORMAL...WITH AFTERNOON MAX TEMPS WELL INTO THE 80S
IN LOWER ELEVATIONS TOWARD THE TN BORDER...WITH 70S ACROSS THE
WESTERN MOUNTAINS.
THE WEDGE WILL PEAK OVERNIGHT AND INTO SUNDAY. LOW CLOUDS ARE
EXPECTED TO PERSIST INTO SUNDAY MORNING...WHICH WILL HOLD MIN
TEMPS CLOSER TO NORMAL VALUES FOR EARLY SEPTEMBER. ONLY LIMITED
SHOWER ACTIVITY IS EXPECTED OVERNIGHT IN THE FAR SOUTHWEST. CANNOT
COMPLETELY RULE OUT SOME LIGHT DRIZZLE ON THE EAST SIDE OF THE
ALLEGHANY FRONT (BCB-LWB AREA) EARLY SUNDAY...BUT NOT ENOUGH
CONFIDENCE TO INCLUDE IN THE GRIDS AT THIS TIME. FOG DEVELOPMENT
SUN MORNING SHOULD BE LIMITED BECAUSE OF CLOUDS AND WIDESPREAD
EASTERLY LOW-LEVEL FLOW.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
AS OF 300 AM EDT SATURDAY...
A PRETTY IMPRESSIVE HYBRID WEDGE FOR AUGUST WILL REMAIN OVER THE
EAST COAST SUNDAY...STRETCHING FROM NEW ENGLAND SOUTH INTO GEORGIA.
MODELS ARE USHERING IN MORE DRIER AIR WITH THE 00Z RUN...PLACING
HIGHER RAINFALL AMOUNTS OF A TENTH OF AN INCH /0.10/ OR MORE OVER
NORTH CAROLINA AND SOUTH. THE INTERACTION OF THE WEDGE BOUNDARY AND
A BROAD BUT WEAK UPPER LEVEL LOW OVER THE SOUTHEASTERN USA WILL KEEP
THE STRONGER CONVECTION OUT OF THE AREA. WE STILL CAN NOT RULE OUT
SOME SHOWERS AND THUNDERSTORMS AS WEAK IMPULSES TRACK AROUND THIS
LOW AND OVER THE AREA. THE COMBINATION OF EASTERLY FLOW AND A
STRONGER WEDGE WILL KEEP TEMPERATURES COOLER THAN NORMAL ALONG AND
EAST OF THE BLUE RIDGE SUNDAY AFTERNOON. DOWNSLOPE FLOW WILL HELP
WARM THE WEST WITH TEMPERATURES RUNNING ABOVE NORMAL. THE OVERALL
TEMPERATURE PICTURE FOR THE AREA WILL BE UNIFORM WITH SUNDAY`S
AFTERNOON HIGHS RANGING FROM THE UPPER 70S TO LOWER 80S.
ON MONDAY...THE PARENT HIGH OVER NEW ENGLAND WILL DRIFT
EAST...LEAVING A RESIDUAL BAGGY HIGH OVER THE MID ATLANTIC REGION.
MEANWHILE...THE UPPER LEVEL LOW RETROGRADES WEST ACROSS THE GULF
STATES. WITH THE DEPARTURE OF THE TWO MAIN WEATHER
FEATURES...AFTERNOON HEATING WILL GENERATE SCATTERED SHOWERS AND
THUNDERSTORMS OVER THE MOUNTAINS DURING THE AFTERNOON. THESE SLOW
MOVING STORMS COULD PRODUCE LOCALIZED HEAVY DOWNPOURS. THESE SHOWERS
WILL FADE WITH LOSE OF HEATING. MORE SUN IS EXPECTED MONDAY WHICH
WILL LEAD TO TEMPERATURES RETURNING TO NORMAL...ESPECIALLY ACROSS
THE PIEDMONT. HOWEVER...WITH LIGHT SOUTHEASTERLY FLOW...WE STILL
EXPECT UNIFORM TEMPERATURES IN THE LOW TO MID 80S ACROSS THE
AREA...UPPER 70S ALONG HIGHER RIDGES.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 330 PM EDT FRIDAY...
A GENERAL SUMMERTIME WEATHER PATTERN WILL RETURN FOR THE MIDDLE OF
NEXT WEEK...WITH SPOTTY SHOWERS AND THUNDERSTORMS DEVELOPING EARLY
EACH AFTERNOON WITH DAYTIME HEATING...AND DIMINISHING TOWARD SUNSET
AS HEATING ENDS. EXPECT ONLY SPOTTY COVERAGE OF RAINFALL ON TUESDAY
DUE TO WEAK SUPPORTING DYNAMICS...HOWEVER COVERAGE WILL INCREASE
EACH DAY FOR WEDNESDAY AND THURSDAY AS A COLD FRONT APPROACHES FROM
THE NORTHWEST.
BY NEXT THURSDAY...LONG RANGE WEATHER FORECAST MODELS DIFFER AS TO
WHERE THE COLD FRONT WILL BE LOCATED...WITH THE ECMWF MODEL BRINGING
THE FRONT ACROSS OUR AREA...WHILE THE GFS MODEL KEEPS THE FRONT WELL
TO OUR NORTH. GIVEN WHAT APPEARS TO BE WEAK UPPER LEVEL SUPPORT TO
GIVE THE FRONT A SOUTHWARD PUSH...HAVE TRENDED TOWARD THE GFS MODEL
AND TRIMMED BACK RAIN CHANCES FOR THAT DAY.
EXPECT WARM AND MUGGY CONDITIONS FOR THE PERIOD...WITH HIGHS RANGING
FROM THE UPPER 70S/LOW 80S ACROSS THE MOUNTAINS...TO THE UPPER 80S
FOR THE PIEDMONT. LOWS WILL HOLD GENERALLY IN THE LOW TO MID
60S...PERHAPS WITH A FEW UPPER 50S ACROSS THE MOUNTAINS.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
AS OF 145 AM EDT SATURDAY...
BACKDOOR COLD FRONT...LIKELY AIDED BY EVENING CONVECTION...APPEARS
TO BE NEAR A CRW- TRI- CLT LINE...DRIFTING SLOWLY WEST.
HOWEVER...THE TRUE BACKDOOR FRONT APPEARS TO BE NEAR THE BLUE
RIDGE. EVENING SHRA/TSRA ACTIVITY HAS GENERALLY DISSIPATED...BUT
AN ISOLATED SHRA/TSRA PERSISTS BETWEEN LYH AND ROA NEAR THE TRUE
BACKDOOR FRONTAL BOUNDARY. CANNOT TOTALLY RULE OUT AN ISOLD SHRA
TRACKING WEST TO NEAR ROA/BCB OVER THE NEXT FEW HOURS...BUT NOT
ENOUGH CONFIDENCE TO INCLUDE IN THE TAF. OTHERWISE...WITH LOSS OF
DAYTIME HEATING...NOT EXPECTING MUCH MORE OVERNIGHT EXCEPT FOR AN
OCCASIONAL SPRINKLE EAST OF THE BOUNDARY. MARITIME FLOW WILL
CONTINUE TO ADVECT INTO THE AREA FROM THE EAST AND IS EXPECTED TO
RESULT IN DETERIORATING CEILINGS IN THE 08Z-12Z TIME FRAME FROM
EAST TO WEST...ESPECIALLY EAST OF THE BLUE RIDGE. WIDESPREAD MVFR
CIGS ARE EXPECTED TO BE IN PLACE FOR ROA/LYH/DAN IN THIS TIME
FRAME...LINGERING INTO THE MID/LATE MORNING HOURS BEFORE IMPROVING
TO LOW END VFR CIGS. TO THE WEST...EARLIER RAINFALL AND
RADIATIONAL COOLING UNDER CURRENTLY MOSTLY CLEAR SKIES AT LWB WILL
ALLOW FOR DEVELOPMENT OF DENSE FOG...PAR FOR THE COURSE IN RECENT
DAYS. THIS WILL EVOLVE INTO AN MVFR CIG AFT 14Z...LINGERING
THROUGHOUT MUCH OF THE DAY. SIMILAR CONDITIONS EXPECTED AT
BCB...ALTHOUGH CONFIDENCE IN IFR-LIFR BR/FG LESS. FOR BLF...SKIES
ARE CURRENTLY CLEAR...BUT EAST FLOW SHOULD RESULT IN DEVELOPMENT
OF MVFR CIGS BY DAYBREAK...LINGERING THROUGHOUT MUCH OF THE DAY.
FOG DEVELOPMENT APPEARS LESS LIKELY THERE GIVEN EAST WINDS.
FINALLY...INSTABILITY/DEWPOINT BOUNDARY WILL RESIDE NEAR THE I-77
CORRIDOR BY PEAK AFTERNOON HEATING...WHICH COULD SUPPORT
THUNDERSTORMS IN THAT PART OF THE STATE AGAIN THIS AFTERNOON.
WINDS GENERALLY NE-E 6-10KTS WITH LOW END GUSTS AFTER DAYBREAK.
MEDIUM CONFIDENCE IN CIGS THROUGH THE TAF VALID PERIOD.
MEDIUM CONFIDENCE IN VSBYS THROUGH THE TAF VALID PERIOD.
MEDIUM TO HIGH CONFIDENCE IN WIND SPD/DIR THROUGH THE TAF VALID
PERIOD.
MEDIUM CONFIDENCE IN TSRA POTENTIAL WEST THIS AFTERNOON.
EXTENDED AVIATION DISCUSSION...
HIGH PRESSURE WILL GRADUALLY WORK INTO THE REGION BY THE END OF
THE WEEKEND...AND REMAIN OVER THE AREA INTO THE EARLY PART OF
NEXT WEEK. LINGERING MOISTURE AND AN EASTERLY FETCH WILL HELP
MAINTAIN SOME ISOLATED TO SCATTERED SHOWERS ACROSS MAINLY WESTERN
PARTS OF THE AREA. THIS MOISTURE WILL BEGIN TO RETURN NORTH AND
EAST BY MONDAY WITH CHANCES FOR SHOWERS AND THUNDERSTORMS
INCREASING THROUGH MID-WEEK AS INSTABILITY INCREASES AND A COLD
FRONT APPROACHES FROM THE WEST.
PAST SATURDAY...CEILINGS AND VISIBILITIES WILL PRIMARILY BE
VFR OUTSIDE EARLY MORNING PATCHY DENSE FOG AND AFTERNOON
SHOWERS/THUNDERSTORMS.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...RAB
NEAR TERM...RAB
SHORT TERM...RCS
LONG TERM...NF
AVIATION...DS/RAB/WP
AREA FORECAST DISCUSSION
NWS TUCSON AZ
320 AM MST SAT SEP 5 2015
.SYNOPSIS...A MOIST ATMOSPHERE WILL REMAIN IN PLACE THROUGH THIS
WEEKEND...WITH ISOLATED TO SCATTERED MAINLY AFTERNOON AND EVENING
SHOWERS AND THUNDERSTORMS THROUGH SUNDAY. A GRADUALLY REDUCTION IN
AREAL COVERAGE OF STORMS WILL OCCUR EARLY NEXT WEEK. BELOW NORMAL
DAYTIME TEMPERATURES WILL PREVAIL THROUGH THIS WEEKEND...WITH HIGH
TEMPERATURES RETURNING CLOSE TO SEASONAL NORMALS BY THE MIDDLE OF
NEXT WEEK.
&&
.DISCUSSION...MOSTLY CLOUDY CONDITIONS PREVAILED ACROSS THE AREA
THIS MORNING WITH ISOLATED LIGHT SHOWERS OCCURRING. QPF VALUES
RATHER LIGHT...LESS THAN 0.05". LATEST SATELLITE IMAGERY SHOWED THAT
THE MID LEVEL CIRCULATION FROM WEAKENING TS KEVIN HAS BROKEN AWAY
FROM THE LOW LEVELS AND IS BEING LIFTED NE ACROSS CENTRAL BAJA WITH
EYES ON SE AZ. LATEST RUNS OF THE HRRR AND RUC13 INCREASE AREAL
COVERAGE OF LIGHT SHOWERS LATER THIS MORNING INTO THIS AFTERNOON.
WITH THAT IN MIND MADE SOME SLIGHT ADJUSTMENTS TO THE FORECAST.
EMBEDDED AREAS OF THUNDER WILL ALSO OCCUR LATER TODAY. HIGHS TODAY
WELL BELOW NORMAL.
MOISTURE REMAINING IN PLACE ON SUNDAY FOR A CHANCE OF SHOWERS AND
THUNDERSTORMS WITH HIGHS SLIGHTLY WARMER THAN TODAY.
MONDAY AND TUESDAY...ANOTHER TROPICAL SYSTEM IS FORECAST TO PASS
WEST OF SRN BAJA. FOR OUT NECK OF THE CACTI...FLOW ALOFT WILL
BECOME MORE WESTERLY...ESPECIALLY ON TUESDAY. STILL ENOUGH MOISTURE
AROUND FOR A SLIGHT CHANCE OF STORMS BOTH DAYS.
WEDNESDAY AND THURSDAY...THE TRACK OF ABOVE MENTIONED TROPICAL
SYSTEM WILL BE THE DRIVING FACTOR FOR THESE TWO DAYS. EC/CANADIAN
HAS TRACK CLOSER/FURTHER N OFF BAJA COAST VERSUS GFS. FOR NOW WILL
MAINTAIN LOW GRADE MONSOON FORECAST.
HIGHS WILL GRADUALLY WARM TO NEAR NORMAL LEVEL BY EARLY NEXT WEEK.
&&
.AVIATION...VALID THRU 06/12Z.
BKN CLOUDS AT 9-12 KFT AGL. ISOLD -SHRA THIS AM...MAINLY FROM KTUS S
AND E...WILL BECOME SCTD AREA WIDE AFTER 05/20Z WITH ISOLD EMBDD TS.
BRIEF MVFR CONDITIONS POSSIBLE IN AND AROUND THE STRONGEST STORMS.
OUTSIDE OF THUNDERSTORM WIND GUSTS...SURFACE WINDS WILL GENERALLY BE
LESS THAN 10 KTS AND MAINTAIN A MORE SOUTHERLY COMPONENT THAN USUAL
DURING THE AFTERNOON. AVIATION DISCUSSION NOT UPDATED FOR TAF
AMENDMENTS.
&&
.FIRE WEATHER...SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THROUGH
THIS HOLIDAY WEEKEND INTO EARLY NEXT WEEK. WINDS WILL FAVOR A
SOUTHERLY DIRECTION...BUT WILL BE LIGHT ENOUGH TO SEE STRONG TERRAIN
INFLUENCES.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS TOPEKA KS
609 AM CDT SAT SEP 5 2015
...Update to aviation forecast discussion...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 231 AM CDT SAT SEP 5 2015
Not much change to the overall pattern with southwest flow aloft
over the central and southern plains keeping the lee side trough in
place and a decent pressure gradient across eastern KS. Temperatures
will be a few degrees higher today so expect highs in the low to mid
90s with a few locations possibly reaching the upper 90s in central
KS. Southerly winds will again increase later today around 15 to 25
mph with gusts up to 35 mph. Later this morning a weak shortwave
will track over western NE and support showers and storms possibly
as far east as north central KS. The latest runs of the HRRR are now
hinting at isolated development in that area around sunrise, but
decided not to increase pops given the low uncertainty. The models
are showing mid level moisture spreading northward from the gulf
today coupled with cooler 850 mb temperatures across southeast KS.
This may lead to a weaker cap and an isolated shower or storm could
be possible south of I-35 this afternoon as daytime heating erodes
this cap. There is no obvious mid level support or any other focus
for lift so did not increase pops, but it could not be completely
ruled out. Tonight a cold front will drift eastward through the high
plains while several weak mid-level shortwaves track over the same
area. This should support storm development along the front in NE
during the overnight hours although have kept the northern forecast
area dry through sunrise.
.LONG TERM...(Sunday THROUGH Friday)
ISSUED AT 231 AM CDT SAT SEP 5 2015
Front still advancing across the Northern Plains on Sunday and
just starts to move into the far northwestern CWA by the late
afternoon hours. This leaves much of the area parked under the
thermal ridge for Sunday, with temperatures rising well into the
middle 90s. Heat indicies look to range from near 100 to 102F by
the afternoon hours. Northern counties may get some relief
overnight as front moves southward about halfway across the CWA,
but stalls out without a strong push to get the front south of the
area. As storms move into the area, some of the storms could be
strong with good instability available and dry air in the low
levels, but wind shear is not strong nor are the lapse rates
aloft. Front may actually retreat back toward the north on Monday
as next upper shortwave trot moves into the northern plains,
before getting a push southward in the overnight hours Monday
night into early Tuesday. Have highs Monday near 90 in the south
to middle 80s north and will need to watch progression of the
front for sensible weather effects.
Synoptic pattern over the Central Plains remains zonal in nature,
with surface front near the area for much of the remainder of the
week with shortwave profs passing through the flow overhead.
Temperatures slowly fall Tuesday through Friday with rain chances
for much of the period given close proximity of the front. Upper
trot looks to deepen across the Great Lakes late in the week, and
usher in cooler high pressure behind.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z Sunday MORNING)
ISSUED AT 608 AM CDT SAT SEP 5 2015
VFR conditions expected through the taf period.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Sanders
LONG TERM...67
AVIATION...Sanders
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
748 AM CDT SAT SEP 5 2015
...SOUNDING DISCUSSION...
AN UNSTABLE AND MOIST ATMOSPHERE WAS SAMPLED BY THE BALLOON THIS
MORNING WITH AN MLCAPE OVER 2000 J/KG AND A PRECIPITABLE WATER
THAT HAS PERSISTED ABOVE 2 INCHES FOR THE THE LAST 2 DAYS. MOST OF
THIS MOISTURE RICH AIR IS FOUND IN THE LOWER HALF OF THE
ATMOSPHERE WHERE WINDS ARE VARIABLE AND GENERALLY UNDER 10 KNOTS.
IN THE UPPER HALF OF THE ATMOSPHERE...THERE IS SOME DRIER AIR WITH
WINDS FROM THE NORTHWEST OR NORTH WITH A LAYER AVERAGE WIND SPEED
OF 25 TO 35 KNOTS. A CONVECTIVE TEMPERATURE OF 89 SHOULD BE
REACHED NEAR MIDDAY AND THE LATEST HRRR TRENDS TOWARD AN INCREASE
IN AREAL COVERAGE OF SHOWERS AND THUNDERSTORMS BETWEEN 17 AND 18Z.
12Z BALLOON INFO: THERE WERE NO ISSUES WITH THE FLIGHT THIS
MORNING THAT LASTED 101 MINUTES AND TRAVELED 28 MILES DOWNRANGE
FROM THE OFFICE. THE BALLOON ASCENDED TO A HEIGHT OF 19.3 MILES
ABOVE THE GROUND BURSTING OVER THE LOWER NINTH WARD.
ANSORGE
&&
.PREV DISCUSSION... /ISSUED 401 AM CDT SAT SEP 5 2015/
SHORT TERM...
ANOTHER DAY OF SUMMER WEATHER ACROSS THE FORECAST AREA...WITH
TEMPERATURES RISING BACK INTO THE LOWER TO MIDDLE 90S AND SOME
SCATTERED DIURNALLY INDUCED CONVECTION FROM LATE MORNING THROUGH
THE AFTERNOON HOURS. IT LOOKS LIKE CONVECTIVE CHANCES WILL BE
HIGHEST ALONG THE IMMEDIATE COAST OF LOUISIANA THIS MORNING...AND
THEN THE RISK OF CONVECTION WILL TRANSITION MORE INLAND AS THE DAY
PROCEEDS. IT LOOKS LIKE SOME HIGHER THETA E VALUES AND INCREASED
MOISTURE POOLING DUE TO A CONVERGENT WIND FIELD WILL BE FOUND
OVER THE FAR WESTERN PART OF THE CWA...CLOSER TO THE ATCHAFALAYA
BASIN...AND WOULD EXPECT TO SEE SOMEWHAT HIGHER CONVECTIVE CHANCES
IN THAT REGION. RAIN CHANCES COULD INCREASE TO AROUND 30-40
PERCENT OVER THE FAR WESTERN PARISHES...WITH 20 TO 30 PERCENT RAIN
CHANCES FOR THE REMAINDER OF THE AREA TODAY. ANY CONVECTION WILL
BE TROPICAL IN NATURE...WITH A QUICK HIT OF HEAVY RAINFALL FOR
SEVERAL MINUTES AND THEN A RETURN TO THE HOT AND STEAMY
CONDITIONS THAT PRECEDED THE SHOWER OR STORM.
A SLOWLY RETROGRADING UPPER LEVEL LOW WILL SHIFT FROM THE
SOUTHEASTERN CONUS INTO THE EASTERN GULF OF MEXICO SUNDAY THROUGH
TUESDAY. INITIALLY...THE REGION WILL REMAIN ON THE DRIER AND MORE
STABLE SIDE OF THE UPPER LEVEL LOW...AND EXPECT TO SEE CONTINUED
SUMMER LIKE WEATHER ACROSS THE AREA WITH SCATTERED AFTERNOON
CONVECTION AND HIGHS RISING INTO THE LOWER TO MIDDLE 90S ACROSS
THE AREA THROUGH MONDAY. HOWEVER...ON TUESDAY...THE UPPER LEVEL
LOW WILL BECOME MORE CENTERED OVER THE FORECAST AREA. WITH THE LOW
DIRECTLY OVER THE AREA...STRONGER FORCING WILL TAKE HOLD
ALOFT...AND A PLUME OF DEEPER TROPICAL MOISTURE WILL STREAM INTO
THE REGION ON THE BACK OF DEEPENING SOUTHEASTERLY FLOW. AS A
RESULT...EXPECT TO SEE HIGHER CHANCES OF RAIN ALONG THE COAST AND
HAVE POPS BOOSTED UP TO 40 PERCENT. CLOUD COVER WILL ALSO BE ON
THE INCREASE...AND EXPECT TO SEE DAYTIME HIGHS FALL BACK INTO THE
UPPER 80S AND LOWER 90S BY TUESDAY.
LONG TERM...
BOTH THE EURO AND GFS INDICATE THAT THE RETROGRADING TROUGH WILL
BEGIN TO WEAKEN ON WEDNESDAY...AS A DEEPENING NORTHERN STREAM
TROUGH BEGINS TO INFLUENCE THE REGION. THERE WILL STILL BE AMPLE
FORCING AND LIFT OVER THE REGION AS THE COMBINATION OF THE
WEAKENING SYSTEM AND INCREASING POSITIVE VORTICITY ADVECTION FROM
THE APPROACHING NORTHERN STREAM TROUGH WORK IN CONJUNCTION. AS A
RESULT...KEEP CHANCE POPS IN PLACE DURING PEAK HEATING HOURS ON
WEDNESDAY.
BY THURSDAY...THE SOUTHERN STREAM TROUGH WILL HAVE BECOME FULLY
INTEGRATED INTO THE MUCH STRONGER NORTHERN STREAM TROUGH AS IT
CONTINUES TO DIG INTO THE LOWER MISSISSIPPI VALLEY. AS THIS TROUGH
DEEPENS...A FAIRLY STRONG COLD FRONT WILL FORM OVER THE SOUTHERN
PLAINS AND BEGIN TO APPROACH THE GULF COAST. HOWEVER...THE
FORECAST AREA SHOULD BE JUST FAR ENOUGH SOUTH TO AVOID IMPACTS
FROM THIS FRONT ON THURSDAY. AS A RESULT...ONLY EXPECT TO SEE THE
SAME PATTERN OF SCATTERED MAINLY AFTERNOON CONVECTION ON THURSDAY.
THE FRONT WILL BEGIN TO INFLUENCE THE REGION MORE DIRECTLY
THURSDAY NIGHT AND ESPECIALLY ON FRIDAY AND SATURDAY AS A SLOW FRONTAL
PASSAGE OCCURS. EXPECT TO SEE SEVERAL WAVES OF SHOWERS AND
THUNDERSTORMS MOVE ACROSS THE AREA AS A SERIES OF WEAK UPPER
LEVEL IMPULSES RIDING ON THE BACK OF A JET STREAK ALOFT SLIDE
ACROSS THE GULF SOUTH. THE SURFACE FRONT WILL SERVE AS A LOW LEVEL
FOCUS FOR CONVECTION TO INITIATE AS THESE IMPULSES ALOFT MOVE
THROUGH. GIVEN THESE CONDITIONS...HAVE HIGH END CHANCE POPS IN
PLACE FOR THE END OF THE WEEK. HIGHS WILL BE MUCH COOLER DUE TO
THE EXPECTED RAINFALL AND CLOUD COVER...WITH TEMPERATURES ONLY
RISING INTO THE MIDDLE TO UPPER 80S.
AVIATION...
NOT AS MUCH TS COVERAGE EXPECTED TODAY. WILL SHOW VCTS FOR BTR AND
HDC SINCE THOSE TWO TERMINALS SHOULD HAVE THE BEST CHANCES OF
RECEIVING ANY ACTIVITY. VFR CONDITIONS WILL BE THE NORM THROUGH THE
TAF PERIOD FOR MOST SITES. WILL SHOW SOME VIS RESTRICTIONS FOR
BTR...HDC AND HUM SINCE THEY MAY GET RAIN TODAY. IF NO RAIN...THEN
VIS WILL ONLY HAVE MINOR MVFR RESTRICTIONS. &&
MARINE...
PRESSURE GRADIENT IS RELAXED ACROSS THE GULF...FAIRLY NORMAL FOR THE
LATE SUMMER DOLDRUMS. DEEP TROPICAL MOISTURE AND AN UPPER TROUGH WILL
REMAIN OVER THE GULF. THIS WEAKNESS WILL KEEP HIGHER CHANCES OF TS
ACTIVITY IN THE COASTAL WATERS THROUGH MUCH OF THE FORECAST. WINDS
AND SEAS WILL BE HIGHER NEAR SCATTERED TS. WIND GUSTS COULD BE AS
HIGH AS 30 KNOTS WITH THE STRONGEST ACTIVITY. OUTSIDE TS
ACTIVITY...CONDITIONS WILL REMAIN RATHER BENIGN WITH A WEAK
PRESSURE GRADIENT. NOCTURNAL ACTIVITY WILL BE THE MOST ABUNDANT
WHILE THERE WILL BE A GENERAL DECREASE IN ACTIVITY DURING THE
LATE MORNING THROUGH LATE AFTERNOON HOURS.
DECISION SUPPORT...
DSS CODE....GREEN.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...NONE.
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED WATCH/WARNING/ADVISORY
ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE RISK SVR AND/OR DIRECT
TROPICAL THREATS; EVENTS OF NATIONAL SIGNIFICANCE
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 96 72 95 70 / 30 30 20 20
BTR 92 73 95 73 / 30 20 20 20
ASD 92 75 92 73 / 30 30 20 20
MSY 91 77 92 76 / 30 20 30 20
GPT 91 76 90 74 / 30 20 30 20
PQL 91 74 91 73 / 30 20 30 20
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1039 AM EDT SAT SEP 5 2015
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 308 AM EDT SAT SEP 5 2015
A WARM FRONT WILL LIFT NORTHWARD THROUGH THE REGION TODAY LEADING
TO SOME SHOWERS AND THUNDERSTORMS. HIGH PRESSURE CONTROLS OUR
WEATHER ON SUNDAY WHICH SHOULD END UP A MOSTLY DRY AND VERY WARM
DAY. THE CHANCES FOR SHOWERS AND THUNDERSTORMS WILL INCREASE AS WE
GO THROUGH LABOR DAY AND INTO TUESDAY AS A SLOW MOVING COLD FRONT
NEARS FROM THE WEST. THE TEMPERATURES WILL STILL END UP WELL ABOVE
NORMAL EARLY NEXT WEEK.
&&
.UPDATE...
ISSUED AT 1039 AM EDT SAT SEP 5 2015
WE HAVE UPDATED TO FCST THIS MORNING TO EXTEND THE DENSE FOG
ADVISORY UNTIL NOON UP NORTH. WE HAVE ALSO INCREASED THE
SHOWER/STORM CHCS DOWN SOUTH WITH PLENTY OF COVERAGE ALREADY IN
PLACE DOWN THERE.
THE FOG UP NORTH HAS BEEN SLOW TO DISSIPATE THIS MORNING WITH MANY
LOCATIONS STILL AT 1/4SM OR LESS LEADING UP TO THE INITIAL
EXPIRATION TIME OF 10 AM THIS MORNING. WITH A LACK OF WIND TO MIX
THINGS UP AND PLENTY OF STRATUS IN PLACE...IT WILL TAKE A LITTLE
LONGER THAN PREVIOUSLY EXPECTED TO MIX IT OUT. WE GAVE IT UNTIL
NOON FOR MORE OF A BUFFER. WE WILL CANCEL IT EARLY IF ALL SITES
COME UP SOONER.
PLENTY OF SHOWERS AND STORMS ACROSS THE SOUTH THIS MORNING. THE
PESKY WEAK UPPER LOW THAT HAS BEEN MEANDERING ACROSS THE STATE THE
PAST COUPLE OF DAYS IS OVER LAKE MICHIGAN EARLY THIS MORNING. IT
NOW LOOKS LIKE IT IS MAKING A MOVE TO THE EAST...AND FIRING PLENTY
OF SHOWERS/STORMS AHEAD OF IT WITH THE MOIST AIR MASS IN PLACE.
IT APPEARS THIS WILL CONTINUE EAST THROUGH THE DAY AND PUSH THE
MORE WIDESPREAD COVERAGE EAST BY LATER THIS AFTERNOON. WE CAN NOT
RULE OUT A POP UP SHOWER/STORM WITH THE UPPER LOW STILL NEARBY.
WEAK SHEAR AND LIMITED INSTABILITY WILL KEEP THINGS GENERALLY
TAME. HEAVY DOWNPOURS WOULD BE THE GREATEST THREAT WITH THE SLOW
MOVEMENT.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 308 AM EDT SAT SEP 5 2015
DENSE FOG HAS BEEN INCREASING OVER THE PAST FEW HOURS AND NOW
COVERS MUCH OF THE REGION. HRRR RUC SUGGESTS THE FOG WILL PERSIST
THROUGH DAYBREAK. WILL GO WITH AN ADVISORY AND CARRY IT UNTIL MID
MORNING. WE MAY SEE GRADUAL IMPROVEMENT IN THE VISIBILITIES FROM
SOUTH TO NORTH BEFORE DAYBREAK AS THE ELEVATED WARM FRONT MOVES
IN.
THE ATMOSPHERE WILL BE UNSTABLE THROUGH THE DAY. SOME LIFT ARRIVES
WITH THE ELEVATED WARM FRONT MOVING IN THIS MORNING FROM THE
SOUTH. THEREFORE WILL KEEP THE MENTION OF SHOWERS AND
THUNDERSTORMS IN THE FORECAST. LITTLE OR NO FORCING IS AROUND
TONIGHT INTO SUNDAY. WILL KEEP IT DRY FOR NOW. THE ATMOSPHERE
BECOMES RATHER UNSTABLE ON SUNDAY...SO WILL NEED TO MONITOR THIS
CLOSELY. SUNDAY SHOULD BE ONE OF THE WARMEST DAYS OF THE SEASON AS
THE LOW LEVEL THERMAL RIDGE ADVECTS IN FROM THE SOUTHWEST.
WILL FEATURE AN INCREASING RISK FOR SHOWERS AND THUNDERSTORMS ON
LABOR DAY. MODELS VARY ON THE TIMING OF ANY PRECIPITATION. HOWEVER
GIVEN THE APPROACHING FRONT DURING THE AFTERNOON WILL ENCOUNTER AN
UNSTABLE AIRMASS...IS SEEMS THAT A RISK FOR THUNDERSTORMS WILL
EXIST. WILL HIGHLIGHT THE AFTERNOON FOR POSSIBLE THUNDERSTORMS.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 308 AM EDT SAT SEP 5 2015
MAIN FOCUS IS CURRENTLY ON THE THREAT FOR HEAVY RAINFALL MONDAY
NIGHT THROUGH TUESDAY NIGHT WITH SOME TRAINING THUNDERSTORMS
POSSIBLE IN ASSOCIATION WITH MAINLY UNIDIRECTIONAL WINDS IN THE
PROFILE...A VERY MOIST AIRMASS...AND A WARM FRONT LIFTING THROUGH
DURING THIS PERIOD. MANY AREAS NEAR AND NORTH OF I-96 ARE EXPECTED
TO RECEIVE ONE TO TWO INCHES OF RAIN BY WEDNESDAY MORNING WITH
HIGHER AMOUNTS QUITE POSSIBLE.
I BELIEVE THERE ARE SOME KEY INGREDIENTS COMING IN PLACE FOR LOCALLY
EXCESSIVE RAINFALL ACROSS WEST CENTRAL AND SOUTHWEST LOWER MI. AS
HAS BEEN MENTIONED MANY TIMES...A WEAK COLD FRONT WILL WASH OUT
ACROSS THE CWA MONDAY...WHICH WILL BECOME STATIONARY AND THEN LIFT
NORTH AS A WARM FRONT TUESDAY. JUST HOW FAR NORTH THIS BOUNDARY
LIFTS IS QUESTIONABLE GIVEN NUMEROUS AREAS OF CONVECTION THAT COULD
SUPPRESS THE FRONT SOUTHWARD. CURRENTLY FAVORING THE ECMWF WITH THIS
SYSTEM GIVEN A FEW DIFFERENT GYRATIONS NOTED WITH THE GFS RECENTLY
WITH HOW QUICK THE BOUNDARY WILL MOVE THROUGH.
DEEP LAYER RH (H1000-H500) ON TUESDAY COULD TOP 90% FOR A GOOD
PORTION OF THE CWA...ESPECIALLY FROM GRR TO THE NORTH. ALL OF THE
MODELS ARE ALSO SHOWING SOME H1000-H700 WIND CONVERGENCE. A 20 KT
LLJ AT 00Z TUES STRENGTHENS TO 30-35 KT BY 00Z WED. HIGHER UP...WE
WILL BE SQUARELY IN THE RIGHT ENTRANCE REGION OF A 100 KT JET STREAK
AS H500 POSITIVE VORTICITY ADVECTION MOVES INTO THE CWA DURING THE
MORNING AND AFTERNOON HOURS. NEAR THE SURFACE...THE WARM FRONT WILL
BE DRAPED ACROSS THE CWA NEAR GRR AT 12Z TUESDAY...POSSIBLY LIFTING
NORTH TOWARD ROUTE 10 BY 18Z. DEW POINT READINGS AROUND 70 COUPLED
WITH PW VALUES OF 2.00-2.25" STRONGLY SUGGEST ANY STORMS WOULD BE
CAPABLE OF HEAVY DOWNPOURS. IF THE NWP SOLUTIONS CONTINUE SUPPORTING
THESE DETAILS...COULD FORESEE A FLOOD THREAT FOR AREAS THAT GET THE
MOST PERSISTENT RAINS.
IN TERMS OF ANY SEVERE WEATHER THREAT...IT IS UNCLEAR AT THIS TIME.
ONGOING CONVECTION EARLY TUESDAY COULD HAMPER ANY DESTABILIZATION
DURING THE AFTERNOON. SFC BASED CAPE IS NOT MUCH MORE THAN 1000 J/KG
FOR THE AREA ON TUESDAY...THOUGH BULK SHEAR IS LOOKING MUCH BETTER
OFF THE ECMWF AT AROUND 35-40 KTS. IT IS ALSO SHOWING 100-150 M2/S2
OF 0-1 KM HELICITY COURTESY OF THE WARM FRONT NEARBY. NOT OUT OF THE
QUESTION THERE COULD BE SOME STRONGER STORMS CAPABLE OF GUSTY WINDS
AND SOME HAIL IF WE CAN DESTABILIZE SUFFICIENTLY.
BEYOND THIS PERIOD...LOOKING AT A PATTERN CHANGE FOR THE SECOND HALF
OF THE WEEK AND THE WEEKEND IN PARTICULAR. TROPICAL STORM IGNACIO
WILL GET SWEPT UP IN MID LEVEL FLOW OVER THE GULF OF ALASKA.
FOLLOWING THE ECMWF H500 HEIGHT FIELD...THIS HELPS DIG A TROUGH INTO
THE GREAT LAKES FOR FRIDAY AND SATURDAY...WITH CHILLY TEMPS AND
SCATTERED SHOWERS EXPECTED BY SATURDAY WITH HIGHS STRUGGLING INTO
THE 60S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 730 AM EDT SAT SEP 5 2015
SCATTERED THUNDERSTORMS THIS MORNING WILL IMPACT SOME OF THE TAF
SITES AS A WARM FRONT PUSHES NORTH. WIDESPREAD DENSE FOG WILL
LIFT SLOWLY NORTH AND DISSIPATE THIS MORNING. GENERALLY VFR
WEATHER THEN SETS UP IN AN UNSTABLE AIRMASS. SO WILL MAINTAIN A
RISK FOR THUNDERSTORMS...AS VCTS. TONIGHT THE RISK FOR
THUNDERSTORMS LOWERS...BUT WE MAY SEE FOG REFORMING ONCE AGAIN.
&&
.MARINE...
ISSUED AT 308 AM EDT SAT SEP 5 2015
WINDS AND WAVES INCREASE SUNDAY INTO SUNDAY NIGHT AS THE WARM AIR
ADVECTION STRENGTHS AHEAD OF THE APPROACHING COLD FRONT. WILL NEED
TO MONITOR LITTLE AND BIG SABLE POINTS FOR A POSSIBLE SMALL CRAFT
ADVISORY AND ASSOCIATED BEACH HAZARDS. RIGHT NOW I HAVE WAVES
INCREASING TO 2 TO 4 FEET.
&&
.HYDROLOGY...
ISSUED AT 1054 AM EDT FRI SEP 4 2015
NO CONCERNS EXIST IN THE NEAR TERM. QUESTIONS ARISE GOING INTO NEXT
WEEK AS A BOUNDARY DRAPES ITSELF SOMEWHERE THROUGH OR NEAR THE GREAT
LAKES REGION.
AREA RIVERS HAVE RESPONDED PRETTY WELL TO YESTERDAYS RAINFALL.
LOCALIZED TOTALS OF MORE THAN TWO INCHES RESULTED IN DECENT UPWARD
TRENDS AT A FEW FORECAST POINTS. MOST NOTABLE IS SYCAMORE CREEK AT
HOLT...WHICH HAS LEVELED OFF ABOUT A FOOT BELOW ADVISORY CRITERIA.
PROVIDED THAT ADDITIONAL RAINFALL IS LIMITED...HOLT SHOULD CONTINUE
ITS DOWNWARD TREND. OTHER SITES HAVE ALSO LEVELED OFF AND RESPONSES
HAVE BEEN MINOR.
RAINFALL THROUGH THE WEEKEND IS EXPECTED TO BE SCATTERED WITH
LOCALIZED HEAVY RAIN POSSIBLE IN OR AROUND THUNDERSTORMS. CONDITIONS
ARE NOT FAVORABLE FOR WIDESPREAD HEAVY RAIN. A PATTERN CHANGE WILL
TAKE PLACE NEXT WEEK AND ITS ASSOCIATED BOUNDARY LOOKS TO BE MOVING
SLOWLY. DIFFERENCES IN LONG RANGE MODELS PUT A CAP ON ANY HIGH
CONFIDENCE. HOWEVER...PWATS ARE 1.5-2.0 INCHES AND THE SLOW
PROGRESSION OF THE BOUNDARY COULD RESULT IN PRETTY DECENT RAINFALL
TOTALS MONDAY THROUGH WEDNESDAY. THE SETUP MAY SUGGEST MORE THAN AN
INCH...WITH AREAS EXCEEDING A COUPLE OF INCHES IF STORMS ARE SLOW
MOVERS. THIS WILL LIKELY BE THE FOCUS HYDRO-WISE OVER THE NEXT
FEW DAYS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...DENSE FOG ADVISORY UNTIL NOON EDT TODAY FOR MIZ037>040-043>046-
050>052.
LM...NONE.
&&
$$
UPDATE...NJJ
SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...HOVING
AVIATION...MJS
HYDROLOGY...JAM
MARINE...MJS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
734 AM EDT SAT SEP 5 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 308 AM EDT SAT SEP 5 2015
A WARM FRONT WILL LIFT NORTHWARD THROUGH THE REGION TODAY LEADING
TO SOME SHOWERS AND THUNDERSTORMS. HIGH PRESSURE CONTROLS OUR
WEATHER ON SUNDAY WHICH SHOULD END UP A MOSTLY DRY AND VERY WARM
DAY. THE CHANCES FOR SHOWERS AND THUNDERSTORMS WILL INCREASE AS WE
GO THROUGH LABOR DAY AND INTO TUESDAY AS A SLOW MOVING COLD FRONT
NEARS FROM THE WEST. THE TEMPERATURES WILL STILL END UP WELL ABOVE
NORMAL EARLY NEXT WEEK.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 308 AM EDT SAT SEP 5 2015
DENSE FOG HAS BEEN INCREASING OVER THE PAST FEW HOURS AND NOW
COVERS MUCH OF THE REGION. HRRR RUC SUGGESTS THE FOG WILL PERSIST
THROUGH DAYBREAK. WILL GO WITH AN ADVISORY AND CARRY IT UNTIL MID
MORNING. WE MAY SEE GRADUAL IMPROVEMENT IN THE VISIBILITIES FROM
SOUTH TO NORTH BEFORE DAYBREAK AS THE ELEVATED WARM FRONT MOVES
IN.
THE ATMOSPHERE WILL BE UNSTABLE THROUGH THE DAY. SOME LIFT ARRIVES
WITH THE ELEVATED WARM FRONT MOVING IN THIS MORNING FROM THE
SOUTH. THEREFORE WILL KEEP THE MENTION OF SHOWERS AND
THUNDERSTORMS IN THE FORECAST. LITTLE OR NO FORCING IS AROUND
TONIGHT INTO SUNDAY. WILL KEEP IT DRY FOR NOW. THE ATMOSPHERE
BECOMES RATHER UNSTABLE ON SUNDAY...SO WILL NEED TO MONITOR THIS
CLOSELY. SUNDAY SHOULD BE ONE OF THE WARMEST DAYS OF THE SEASON AS
THE LOW LEVEL THERMAL RIDGE ADVECTS IN FROM THE SOUTHWEST.
WILL FEATURE AN INCREASING RISK FOR SHOWERS AND THUNDERSTORMS ON
LABOR DAY. MODELS VARY ON THE TIMING OF ANY PRECIPITATION. HOWEVER
GIVEN THE APPROACHING FRONT DURING THE AFTERNOON WILL ENCOUNTER AN
UNSTABLE AIRMASS...IS SEEMS THAT A RISK FOR THUNDERSTORMS WILL
EXIST. WILL HIGHLIGHT THE AFTERNOON FOR POSSIBLE THUNDERSTORMS.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 308 AM EDT SAT SEP 5 2015
MAIN FOCUS IS CURRENTLY ON THE THREAT FOR HEAVY RAINFALL MONDAY
NIGHT THROUGH TUESDAY NIGHT WITH SOME TRAINING THUNDERSTORMS
POSSIBLE IN ASSOCIATION WITH MAINLY UNIDIRECTIONAL WINDS IN THE
PROFILE...A VERY MOIST AIRMASS...AND A WARM FRONT LIFTING THROUGH
DURING THIS PERIOD. MANY AREAS NEAR AND NORTH OF I-96 ARE EXPECTED
TO RECEIVE ONE TO TWO INCHES OF RAIN BY WEDNESDAY MORNING WITH
HIGHER AMOUNTS QUITE POSSIBLE.
I BELIEVE THERE ARE SOME KEY INGREDIENTS COMING IN PLACE FOR LOCALLY
EXCESSIVE RAINFALL ACROSS WEST CENTRAL AND SOUTHWEST LOWER MI. AS
HAS BEEN MENTIONED MANY TIMES...A WEAK COLD FRONT WILL WASH OUT
ACROSS THE CWA MONDAY...WHICH WILL BECOME STATIONARY AND THEN LIFT
NORTH AS A WARM FRONT TUESDAY. JUST HOW FAR NORTH THIS BOUNDARY
LIFTS IS QUESTIONABLE GIVEN NUMEROUS AREAS OF CONVECTION THAT COULD
SUPPRESS THE FRONT SOUTHWARD. CURRENTLY FAVORING THE ECMWF WITH THIS
SYSTEM GIVEN A FEW DIFFERENT GYRATIONS NOTED WITH THE GFS RECENTLY
WITH HOW QUICK THE BOUNDARY WILL MOVE THROUGH.
DEEP LAYER RH (H1000-H500) ON TUESDAY COULD TOP 90% FOR A GOOD
PORTION OF THE CWA...ESPECIALLY FROM GRR TO THE NORTH. ALL OF THE
MODELS ARE ALSO SHOWING SOME H1000-H700 WIND CONVERGENCE. A 20 KT
LLJ AT 00Z TUES STRENGTHENS TO 30-35 KT BY 00Z WED. HIGHER UP...WE
WILL BE SQUARELY IN THE RIGHT ENTRANCE REGION OF A 100 KT JET STREAK
AS H500 POSITIVE VORTICITY ADVECTION MOVES INTO THE CWA DURING THE
MORNING AND AFTERNOON HOURS. NEAR THE SURFACE...THE WARM FRONT WILL
BE DRAPED ACROSS THE CWA NEAR GRR AT 12Z TUESDAY...POSSIBLY LIFTING
NORTH TOWARD ROUTE 10 BY 18Z. DEW POINT READINGS AROUND 70 COUPLED
WITH PW VALUES OF 2.00-2.25" STRONGLY SUGGEST ANY STORMS WOULD BE
CAPABLE OF HEAVY DOWNPOURS. IF THE NWP SOLUTIONS CONTINUE SUPPORTING
THESE DETAILS...COULD FORESEE A FLOOD THREAT FOR AREAS THAT GET THE
MOST PERSISTENT RAINS.
IN TERMS OF ANY SEVERE WEATHER THREAT...IT IS UNCLEAR AT THIS TIME.
ONGOING CONVECTION EARLY TUESDAY COULD HAMPER ANY DESTABILIZATION
DURING THE AFTERNOON. SFC BASED CAPE IS NOT MUCH MORE THAN 1000 J/KG
FOR THE AREA ON TUESDAY...THOUGH BULK SHEAR IS LOOKING MUCH BETTER
OFF THE ECMWF AT AROUND 35-40 KTS. IT IS ALSO SHOWING 100-150 M2/S2
OF 0-1 KM HELICITY COURTESY OF THE WARM FRONT NEARBY. NOT OUT OF THE
QUESTION THERE COULD BE SOME STRONGER STORMS CAPABLE OF GUSTY WINDS
AND SOME HAIL IF WE CAN DESTABILIZE SUFFICIENTLY.
BEYOND THIS PERIOD...LOOKING AT A PATTERN CHANGE FOR THE SECOND HALF
OF THE WEEK AND THE WEEKEND IN PARTICULAR. TROPICAL STORM IGNACIO
WILL GET SWEPT UP IN MID LEVEL FLOW OVER THE GULF OF ALASKA.
FOLLOWING THE ECMWF H500 HEIGHT FIELD...THIS HELPS DIG A TROUGH INTO
THE GREAT LAKES FOR FRIDAY AND SATURDAY...WITH CHILLY TEMPS AND
SCATTERED SHOWERS EXPECTED BY SATURDAY WITH HIGHS STRUGGLING INTO
THE 60S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 730 AM EDT SAT SEP 5 2015
SCATTERED THUNDERSTORMS THIS MORNING WILL IMPACT SOME OF THE TAF
SITES AS A WARM FRONT PUSHES NORTH. WIDESPREAD DENSE FOG WILL
LIFT SLOWLY NORTH AND DISSIPATE THIS MORNING. GENERALLY VFR
WEATHER THEN SETS UP IN AN UNSTABLE AIRMASS. SO WILL MAINTAIN A
RISK FOR THUNDERSTORMS...AS VCTS. TONIGHT THE RISK FOR
THUNDERSTORMS LOWERS...BUT WE MAY SEE FOG REFORMING ONCE AGAIN.
&&
.MARINE...
ISSUED AT 308 AM EDT SAT SEP 5 2015
WINDS AND WAVES INCREASE SUNDAY INTO SUNDAY NIGHT AS THE WARM AIR
ADVECTION STRENGTHS AHEAD OF THE APPROACHING COLD FRONT. WILL NEED
TO MONITOR LITTLE AND BIG SABLE POINTS FOR A POSSIBLE SMALL CRAFT
ADVISORY AND ASSOCIATED BEACH HAZARDS. RIGHT NOW I HAVE WAVES
INCREASING TO 2 TO 4 FEET.
&&
.HYDROLOGY...
ISSUED AT 1054 AM EDT FRI SEP 4 2015
NO CONCERNS EXIST IN THE NEAR TERM. QUESTIONS ARISE GOING INTO NEXT
WEEK AS A BOUNDARY DRAPES ITSELF SOMEWHERE THROUGH OR NEAR THE GREAT
LAKES REGION.
AREA RIVERS HAVE RESPONDED PRETTY WELL TO YESTERDAYS RAINFALL.
LOCALIZED TOTALS OF MORE THAN TWO INCHES RESULTED IN DECENT UPWARD
TRENDS AT A FEW FORECAST POINTS. MOST NOTABLE IS SYCAMORE CREEK AT
HOLT...WHICH HAS LEVELED OFF ABOUT A FOOT BELOW ADVISORY CRITERIA.
PROVIDED THAT ADDITIONAL RAINFALL IS LIMITED...HOLT SHOULD CONTINUE
ITS DOWNWARD TREND. OTHER SITES HAVE ALSO LEVELED OFF AND RESPONSES
HAVE BEEN MINOR.
RAINFALL THROUGH THE WEEKEND IS EXPECTED TO BE SCATTERED WITH
LOCALIZED HEAVY RAIN POSSIBLE IN OR AROUND THUNDERSTORMS. CONDITIONS
ARE NOT FAVORABLE FOR WIDESPREAD HEAVY RAIN. A PATTERN CHANGE WILL
TAKE PLACE NEXT WEEK AND ITS ASSOCIATED BOUNDARY LOOKS TO BE MOVING
SLOWLY. DIFFERENCES IN LONG RANGE MODELS PUT A CAP ON ANY HIGH
CONFIDENCE. HOWEVER...PWATS ARE 1.5-2.0 INCHES AND THE SLOW
PROGRESSION OF THE BOUNDARY COULD RESULT IN PRETTY DECENT RAINFALL
TOTALS MONDAY THROUGH WEDNESDAY. THE SETUP MAY SUGGEST MORE THAN AN
INCH...WITH AREAS EXCEEDING A COUPLE OF INCHES IF STORMS ARE SLOW
MOVERS. THIS WILL LIKELY BE THE FOCUS HYDRO-WISE OVER THE NEXT
FEW DAYS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR MIZ037>040-
043>046-050>052-056>059-064>067.
LM...NONE.
&&
$$
SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...HOVING
AVIATION...MJS
HYDROLOGY...JAM
MARINE...MJS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
656 AM CDT SAT SEP 5 2015
.SYNOPSIS...
ISSUED AT 400 AM CDT SAT SEP 5 2015
WEAK EMBEDDED SHORT WAVE MOVING QUICKLY ACROSS THE CENTRAL
ROCKIES AND ONTO THE HIGH PLAINS IN SWRLY FLOW ALOFT WORKING IN
CONCERT WITH LLJ TO GENERATE SHRA AND ISOLD TSRA ACROSS PORTIONS
OF WRN NEB EARLY THIS MORNING. MEANWHILE UPPER TROUGH AND
ASSOCIATED LOW OVER THE PAC NW STARTING TO MOVE EWD WHILE HEIGHTS
RISE ACROSS THE PLAINS. THESE TWO THINGS CONTRIBUTING TO
TIGHTEN/INCREASE THE UPPER FLOW AHEAD OF THE LOW IN THE NW.
MOISTURE AND ASSOCIATED CONVECTIVE ACTIVITY FROM TROPICAL STORM
KEVIN MOVING ONSHORE ON THE BAJA PENINSULA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 400 AM CDT SAT SEP 5 2015
FORECAST ISSUES FOR EARLY THIS MORNING INVOLVES THE POTENTIAL FOR
ADDITIONAL CONVECTIVE DEVELOPMENT IN SRN/WRN NEB WHICH SEVERAL OF
THE CAMS SUGGEST WILL HAPPEN THROUGH THE MORNING. RADAR ECHOES
OVER THE LAST FEW HOURS HAVE INCREASED IN THE ERN PANHANDLE...BUT
NEW DEVELOPMENT AS PER THE OPERATIONAL HRRR HAS YET TO OCCUR
ASSOCIATED WITH THE NWD ADVANCING WARM FRONT OVER SRN NEB. SHORT
RANGE MODELS DO HAVE ELEVATED INSTABILITY PRESENT AND SPC
MESOANALYSIS BASED ON RAP SHOWS DEEP MOIST CONVERGENCE INCREASING
TO SUPPORT THIS IDEA. HAVE TRENDED THE HOURLY POP GRIDS TO
REFLECT THIS OCCURRING...DESPITE EXP HRRR AND NSSL WRF NOT
EVOLVING IN THIS MANNER.
ATTENTION THEN TURNS TO ADDITIONAL TSRA DEVELOPMENT THIS
AFTERNOON. AS PREVIOUSLY MENTIONED SHORT WAVE CONTINUES TO MOVE
NEWD INTO THE DAKOTAS TODAY...WEAK LARGE SCALE HEIGHT FALLS ALSO
MOVE OUT OF THE AREA. HOWEVER AS PAC NW UPPER LOW CONTINUES TO
MOVE EWD GOOD HEIGHT FALLS DEVELOP ACROSS WRN MT. THE INCREASED
SWRLY FLOW AHEAD OF THIS FEATURE ALLOWS THE SFC LOW TO REDEVELOP
OVER ERN WY THIS AFTERNOON. AS THIS OCCURS...DEEPER MIXING SOUTH
OF THE SFC LOW WILL DEVELOP THIS AFTERNOON SERVING TO LOWER DEW
POINTS ACROSS THE PANHANDLE. AT THIS SAME TIME...INCREASING SERLY
LOW LEVEL FLOW IN THE TIGHTENING SFC GRADIENT WILL INCREASE DEW
POINTS/LOW LEVEL MOISTURE FURTHER EAST OVER TIME. THE RESULT IS
TO TIGHTEN THE GRADIENT AND EVENTUALLY TO DEVELOP THUNDERSTORMS
ASSOCIATED WITH THIS BOUNDARY. SUITE OF MODELS CONTAIN A WIDE
VARIETY OF SOLUTIONS HOWEVER IN HOW EXTENSIVE THE QPF WILL
BE...IF AT ALL. NAM SUGGESTS A LARGE INCREASE IN PW BY AFTERNOON
/PRIOR TO CONVECTIVE DEVELOPMENT IN THE MODEL/ ASSOCIATED WITH
THE FETCH OF MID/UPPER LEVEL MOISTURE ORIGINATING FROM THE ERN
PAC TROPICS VIA THE SWRLY FLOW. IF DEEP MOIST CONVECTION CAN
DEVELOP...THE WARM MOIST MID LEVELS WOULD ALLOW FOR A CAPE
PROFILE MORE CONDUCIVE TO HEAVY RAIN PRODUCING STORMS AND SHEAR
OF 25-30KTS WOULD BE MARGINAL FOR DEVELOPING STRONG STORMS. AS
ALWAYS HOWEVER SMALL SCALE STORM INTERACTIONS MAY ALLOW FOR MORE
ROBUST DEVELOPMENT ON OCCASION.
TEMPERATURES TODAY WILL BE TRICKY DUE TO LEFT OVER CLOUD COVER
FROM ONGOING CONVECTION AS WELL AS NEW CLOUD COVER FROM
ADDITIONAL DEVELOPMENT THIS AFTERNOON. ASSUMING SRN AREAS WOULD
RECEIVE BEST INSOLATION FOR A LONGER PERIOD OF TIME AND THEREFORE
MAXES ARE HIGHER THERE...THOUGH 90S WILL AGAIN BE COMMON TODAY.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 400 AM CDT SAT SEP 5 2015
SOUTHWEST FLOW TO START THE WEEK TRANSITIONS TO MORE ZONAL FLOW AS
AN UPPER LEVEL LOW LIFTS ACROSS THE NORTHERN ROCKIES INTO THE
CANADIAN PLAINS. A COUPLE OF COLD FRONTS WILL RESULT IN FALLING
TEMPS FOR THE WEEK. MAIN CONCERN IN THE EXTENDED WILL BE TIMING THE
COOL DOWNS AND LOW POP CHANCES THROUGHOUT THE PERIOD.
SUNDAY INTO MONDAY SW FLOW WILL TAP SOME PACIFIC MOISTURE. MODELS
SHOWING SOME MOISTURE FROM THE EASTERN PACIFIC TROPICAL SYSTEMS
GET DRAWN ACROSS THE 4 CORNERS AND TOWARDS THE HIGH PLAINS. THIS
MAY BE ENOUGH TO INCREASE THE MOISTURE IN THE MID/UPPER LEVELS THAT
CAN BE TAPPED BY WEAK DISTURBANCES RIDING ACROSS THE AREA. MODELS
HAVE INCREASE THE LIGHT QPF OVER THE CWA AND CAN NOT ARGUE
NEEDING LOW POPS WITH EACH PASSING WAVE.
MID WEEK A COLD FRONT WILL PUSH ACROSS THE AREA. TIMING OF THE
FRONT AND BETTER MOISTURE RESULTS IN BEST CHANCE FOR PRECIP TO BE
ACROSS THE EASTERN ZONES. BEHIND THE FRONT TEMPS COOL INTO THE
70S...WHICH WOULD BE BELOW NORMAL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 655 AM CDT SAT SEP 5 2015
FCST DIFFICULTIES TODAY INVOLVE THE PRECIP FCST AND ASSOCIATED
CLOUD COVER. ONGOING SHRA OVER NC NEB HAS HAD A COUPLE OF
LIGHTNING FLASHES BUT OVERALL INTENSITY NOT TOO IMPRESSIVE.
OPERATIONAL HRRR HAS HAD POOR RUN TO RUN CONSISTENCY AND EARLIER
DEVELOPED TSRA OVER THE SW NEAR THE WARM FRONT WITH ELEVATED
INSTABILITY BUT PRECIP NEVER MATERIALIZED THOUGH MID LEVEL
CLOUDINESS DID. AGAIN SEVERAL POTENTIAL SOLUTIONS IN THE
CONVECTIVE INITIATION ENVELOPE FOR LATER THIS MORNING AS WELL AS
THIS AFTERNOON WHEN LL FLOW INCREASES IN RESPSONE TO DEVELOPING
LOW PRESSURE IN ERN WY. NAM HAS BEEN TOO AGGRESSIVE WITH DRY LOWER
LAYERS PRESENT UP THROUGH 12Z THIS MORNING. END RESULT IS LITTLE
CONFIDENCE IN ANY ONE SOLUTION. IN ADDITION...BASED ON LATEST SFC OBS
AND RADAR VWP THERE DOES EXISTS SOME LOW LEVEL DIRECTIONAL AND
SPEED SHEAR...BUT AT THIS TIME THE DIFFERENCE IS BELOW CRITERIA.
AS SFC LOW DEVELPS LATER...THERE STILL APPEARS TO BE SOME
TIGHTENING OF THE LOW LEVEL MOISTURE GRAIENT SO HAVE INCLUDED SOME
GUSTS IN TAFS AND...LIKE HAS BEEN THE CASE WITH THE LAST WEEK OR
SO...POTENTIAL CONVECTIVE DEVELOPMENT LOOKS POSSIBLE BUT LACK OF
SHEAR AND LARGE CAPE SHOULD KEEP COVERAGE AND INTENSITY TO A
MINIMUM. FCST CONFIDENCE IS BELOW AVERAGE ON TIMING OF CONVECTION
AT KLBF AND KVTN FOR LATER TODAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JWS
SHORT TERM...JWS
LONG TERM...MASEK
AVIATION...JWS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1010 AM CDT SAT SEP 5 2015
.UPDATE...
ISSUED AT 1010 AM CDT SAT SEP 5 2015
ADJUSTED POPS A BIT FOR CURRENT RADAR TRENDS. THINK WE SHOULD STAY
DRY UNTIL THIS AFTERNOON WHEN THE PRECIP IN WESTERN AND CENTRAL ND
AND SD BEGINS TO MOVE INTO OUR WESTERN COUNTIES. STILL SOME
UNCERTAINTY ON HOW STRONG THE STORMS WILL BE...AS EVEN OUR EASTERN
COUNTIES WHERE THERE HAS BEEN CLEARING ON THE WARM SIDE OF THE
FRONT ARE SEEING MORE CLOUDS MOVE IN. MARGINAL RISK SEEMS ON TRACK
AT THIS POINT BUT WILL MONITOR. FOG ON THE COOL SIDE OF THE FRONT
HAS ALSO BEEN STICKING AROUND LONGER THAN EXPECTED SO EXTENDED THE
MENTION. LOWERED HIGHS A BIT ACROSS THE CWA FOR INCREASED CLOUD
COVER.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 334 AM CDT SAT SEP 5 2015
CONCERN FOR TODAY WILL AGAIN BE SEVERE THUNDERSTORM AND HEAVY RAIN
POTENTIAL. MUCH LIKE YESTERDAY...STRENGTH OF STORMS WILL DEPEND ON
TIMING OF UPPER WAVE AND CLOUD COVER. THE SHORTWAVE OF THE DAY IS
CURRENTLY (08Z) LOCATED ACROSS WESTERN NEBRASKA AND WILL PROPAGATE
TO THE NE THROUGH THE DAY. EXPECTED TIMING OF THIS FEATURE WILL
BRING FORCING INTO THE SOUTHERN FA AFTER 18Z...AND INTO THE
NORTHERN FA AFTER 21Z. THIS TIMING IS SLIGHTLY SLOWER COMPARED
WITH FRIDAY...WHICH MAY ALLOW MORE TIME FOR HEATING. DEEP LAYER
SHEAR WILL NOT BE MUCH STRONGER TODAY...AND SEVERE POTENTIAL WILL
DEPEND ON ENHANCED INSTABILITY DUE TO HEATING. AS OF 08Z...LOW
CLOUDS ON THE COOL SIDE OF THE SFC BOUNDARY ARE ADVANCING TO THE
SOUTH/SOUTHEAST. ANTICIPATE THIS SOUTH/SOUTHEAST ADVANCEMENT OF
CLOUDS TO STALL AROUND MID-MORNING FROM AROUND BEMIDJI TO WAHPETON
(FOLLOWING THE HRRR). ALTHOUGH CLOUDS WILL LIKELY REMAIN ACROSS
MUCH OF EASTERN NORTH DAKOTA...THERE IS THE POTENTIAL FOR
CLEARING ACROSS THE MINNESOTA COUNTIES. MOST CAMS INDICATE THE
BEST POTENTIAL FOR SEVERE STORMS WILL BE TOWARD LATE AFTERNOON
ACROSS NW MN (WHERE FORCING WILL ARRIVE LAST...PROVIDING MORE TIME
FOR HEATING AND GREATER INSTABILITY). WITH PWATS NEAR 2 INCHES
EXPECTED...LOCALLY HEAVY RAIN WILL ALSO BE A CONCERN...ALTHOUGH
THE ENTIRE SYSTEM SHOULD BE PROGRESSIVE AND LIMIT THE COVERAGE OF
FLASH FLOOD POTENTIAL. WILL MENTION RW+ ACROSS NW MN WHERE STRONGER
STORMS ARE MORE LIKELY. CONSIDERING THE MANY VARIABLES
INVOLVED...WILL NOT YET MENTION T+.
COLD FRONT WILL MOVE THROUGH THE REGION ON SUNDAY...WITH
THUNDERSTORMS AGAIN POSSIBLE. TIMING WILL DETERMINE SEVERE
POTENTIAL...WITH MOST GUIDANCE SUGGESTING BEST CHANCES EAST OF THE
REGION (ALTHOUGH SPC DID PLACE THE FAR EASTERN FA IN A SLIGHT
RISK).
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 320 AM CDT SAT SEP 5 2015
SUNDAY NIGHT-MONDAY NIGHT...COOL AND DRY AIRMASS WILL BE IN PLACE.
CYCLONIC FLOW ALOFT MAY LEAD TO SOME SHOWERS.
TUESDAY-FRIDAY...PERIOD BEGINS WITH ZONAL FLOW ALOFT AND AN UPPER
WAVE MOVING ACROSS THE NORTHERN TIER WITH ASSOCIATED COLD FRONT.
THIS WILL BRING A CHANCE OF CONVECTION TO PORTIONS OF NORTHWEST
AND W CNTRL MN. LWT THEN MOVES ACROSS MN THU NIGHT INTO FRI WITH
NW FLOW PATTERN SETTING UP FOR THE END OF THE WEEK. SFC HIGH
PRESSURE OVER THE DAKOTAS SHOULD KEEP REGION DRY FROM FRIDAY INTO
THE WEEKEND. DAYTIME HIGHS WILL BE SEASONALLY COOL WITH MAX TEMPS
THU AND FRI STRUGGLING TO REACH THE 70S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 631 AM CDT SAT SEP 5 2015
LIFR CIGS AFFECTING MOST AREAS EARLY THIS MORNING (EXCEPT FARGO).
THESE CIGS WILL GRADUALLY RISE THROUGH THE DAY...OR MOVE NORTH AS
THE NEXT SYSTEM MOVES TOWARD THE REGION. USED HRRR GUIDANCE FOR
TIMING OF CIGS. THUNDERSTORMS EXPECTED THIS AFTERNOON AND EVENING
ACROSS MUCH OF THE REGION.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...TG
LONG TERM...TG/SPEICHER
AVIATION...TG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1002 AM CDT SAT SEP 5 2015
.UPDATE...
ISSUED AT 951 AM CDT SAT SEP 5 2015
NO SIGNIFICANT CHANGES WITH THIS FORECAST UPDATE. EXPECT A PEAK IN
PRECIPITATION COVERAGE BETWEEN NOW AND MID DAY...DECREASING
THEREAFTER THROUGH THE LATE AFTERNOON AND EARLY EVENING AS THE
SHORTWAVE ACROSS CENTRAL SOUTH DAKOTA THIS MORNING PROPAGATES INTO
NORTHEAST NORTH DAKOTA. SPC HAS MAINTAINED OUR AREA IN A MARGINAL
RISK FOR SEVERE STORMS. THIS IS PLAUSIBLE...YET DEPENDENT ON
HEATING IN LIGHT OF THE WIDESPREAD CLOUD COVER THIS MORNING.
SHOULD CLOUD COVER THIN A BIT...WHICH IS MOST LIKELY ACROSS THE
SOUTHWEST... 60S F DEWPOINTS IN PLACE UNDER SOUTHWEST FLOW ALOFT
WOULD SUPPORT THE POTENTIAL FOR A SEVERE STORM OR TWO.
FOR LATE THIS EVENING AND INTO THE OVERNIGHT...THE 10-13 UTC
OPERATIONAL AND EXPERIMENTAL HRRR ITERATIONS...12 UTC NAM NEST AND
00 UTC WRF-ARW/NMM RUNS ALL SHOW A CONVECTIVE COMPLEX PROPAGATING
OUT OF MONTANA INTO WESTERN NORTH DAKOTA ASSOCIATED WITH STRONG
DIFFLUENCE AHEAD OF THE DEEPENING UPPER LEVEL LOW ACROSS
SOUTHEAST ALBERTA. CERTAINLY COULD NOT RULE OUT A STRONG TO SEVERE
STORM WITH AROUND 1000 J/KG OF ELEVATED CAPE AND AROUND 30-40KTS
OF DEEP LAYER SHEAR.
UPDATE ISSUED AT 603 AM CDT SAT SEP 5 2015
FOR MORNING UPDATE HAVE ADJUSTED POPS A BIT TOWARDS CURRENT
TRENDS WHICH SEEM TO BE PICKED UP RATHER WELL BY THE HRRR MODEL.
HEAVIER PRECIPITATION WILL CONTINUE TO PUSH NORTH TOWARDS
CANADA...BUT BEHIND IT A LINE OF SHOWERS/THUNDERSTORMS STRETCHING
SOUTHWARD WILL SHIFT EASTWARD AND FILL IN A BIT. HAVE ALSO BUMPED
UP FOG COVERAGE A BIT OVER SOUTH CENTRAL NORTH DAKOTA INTO THE
JAMES RIVER VALLEY WHERE VISIBILITIES HAVE DIPPED DOWN TO AROUND
1/4 MILE AT TIMES. THE COVERAGE OF THIS IS NOT WIDESPREAD SO WILL
REFRAIN FROM ISSUING AN ADVISORY...BUT WILL COVER WITH A SPECIAL
WEATHER STATEMENT FOR EARLY THIS MORNING.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY AFTERNOON)
ISSUED AT 410 AM CDT SAT SEP 5 2015
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD CONTINUES TO BE
SHOWER AND THUNDERSTORM POTENTIAL.
CURRENTLY...STRONG EMBEDDED S/WV LIFTING NORTH-NORTHEAST INTO
WESTERN NORTH DAKOTA RESPONSIBLE FOR ROBUST CONVECTION NOW MOVING
INTO MY NORTHWEST AND NORTH CENTRAL. THIS ACTIVITY WILL QUICKLY
MOVE NORTH OF THE CANADIAN BORDER BY 12Z. CONTINUED CHANCES FOR
SHOWERS AND THUNDERSTORMS THIS MORNING WEST AHEAD OF AN UPPER
LEVEL JET AND NEAR A QUASI-STATIONARY FRONTAL BOUNDARY.
ONCE AGAIN A WIDE VARIETY OF SOLUTIONS WITH FORECAST QPF FOR
TODAY. HOWEVER...THERE APPEARS TO BE A DECENT ENOUGH CONSENSUS TO
KEEP HIGH POPS CENTRAL INTO EAST THIS MORNING INTO THE AFTERNOON
WITH ANOTHER STRONG EMBEDDED WAVE LIFTING NORTH-NORTHEAST ACROSS
CENTRAL SOUTH DAKOTA THIS MORNING AND INTO EASTERN NORTH DAKOTA
THIS AFTERNOON. FORCING WILL BE ENHANCED AS THE NOSE OF A STRONG
UPPER LEVEL JET PUSHES NORTHEAST INTO THE DAKOTAS. FOCUSED HIGHER
POPS ALONG THE AFOREMENTIONED QUASI-STATIONARY BOUNDARY. STRONG
MOISTURE FEED CONTINUES FROM TROPICAL STORM KEVIN...SO HEAVY
RAINERS WILL ONCE AGAIN BE POSSIBLE TODAY. IN ADDITION...A FEW
STRONGER STORMS ONCE AGAIN POSSIBLE 1-1.5K MUCAPE AND AROUND 35KTS
OF WIND SHEAR.
THE UPPER JET WILL FORCE THE STATIONARY SFC LOW FINALLY OFF TO
OUR NORTH AND EAST THIS EVENING INTO THE OVERNIGHT ALLOWING FOR A
DRY WESTERLY FLOW TO DEVELOP INTO THE WESTERN DAKOTAS AFTER 00Z.
LINGERING PRECIPITATION POSSIBLE EAST WITH BETTER CHANCES
NORTHWEST AND NORTH CENTRAL TONIGHT NEAR THE TRACK OF THE BASE OF
THE WEST COAST TROUGH LIFTING NORTHEAST ACROSS MONTANA AND INTO
SASKATCHEWAN. ALL AREAS SHOULD BE DRY BY SUNDAY AFTERNOON AS THE
DRY WESTERLY FLOW CONTINUES TO EXPAND ACROSS THE NORTHERN PLAINS.
BREEZY BUT PLEASANT FOR SUNDAY AS SFC DEWPOINT TEMPERATURES FALL
FROM THE 60S AND LOW 70S WE HAVE SEEN THE PAST COUPLE OF DAYS
DOWN INTO THE 40S AND LOW 50S BY SUNDAY AFTERNOON.
.LONG TERM...(SUNDAY EVENING THROUGH FRIDAY)
ISSUED AT 345 AM CDT SAT SEP 5 2015
QUIET WEATHER IS EXPECTED SUNDAY NIGHT AS BROAD AREA OF
PRECIPITATION CONTINUES TO LIFT TO THE NORTHEAST. ON
MONDAY...AREA WILL BE UNDER COOL BROAD CYCLONIC FLOW. THIS MAY
LEAD TO SOME SHOWERS DEVELOPING...AND POSSIBLY A WEAK THUNDERSTORM
OR TWO...OVER SOUTH CENTRAL NORTH DAKOTA INTO THE JAMES RIVER
VALLEY. QUIET WEATHER RETURNS IN THE EVENING WITH LOSS OF DAYTIME
HEATING. QUIET WEATHER IS EXPECTED ON MONDAY WITH WEAK RIDGE
PASSING OVER...THOUGH TEMPERATURES WILL REMAIN COOL. THROUGH THE
REMAINDER OF THE WEEK WILL HAVE OCCASIONAL LOW CHANCES FOR
PRECIPITATION AS A VARIETY OF WEAK DISTURBANCES PASS THROUGH.
TEMPERATURES WILL GRADUALLY WARM TOWARDS THE END OF THE WEEK WITH
RIDGING OVER THE WESTERN CONUS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 951 AM CDT SAT SEP 5 2015
IFR-VLIFR STRATUS AND PATCHY FOG DEVELOPING ACROSS ALL TERMINALS
EARLY THIS SATURDAY MORNING AND SHOULD PERSIST THROUGH THE AM
HOURS. SCATTERED SHOWERS AND THUNDERSTORMS ACROSS WESTERN INTO
NORTH CENTRAL NORTH DAKOTA EARLY THIS SATURDAY MORNING...WITH
THIS ACTIVITY CONTINUING/REDEVELOPING CENTRAL INTO EAST LATER
THIS MORNING AND INTO THE AFTERNOON. FOG AND STRATUS IS EXPECTED
ONCE AGAIN LATE TONIGHT INTO SUNDAY MORNING ACROSS MUCH OF THE
AREA.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...NH
LONG TERM...JJS
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
631 AM CDT SAT SEP 5 2015
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 334 AM CDT SAT SEP 5 2015
CONCERN FOR TODAY WILL AGAIN BE SEVERE THUNDERSTORM AND HEAVY RAIN
POTENTIAL. MUCH LIKE YESTERDAY...STRENGTH OF STORMS WILL DEPEND ON
TIMING OF UPPER WAVE AND CLOUD COVER. THE SHORTWAVE OF THE DAY IS
CURRENTLY (08Z) LOCATED ACROSS WESTERN NEBRASKA AND WILL PROPAGATE
TO THE NE THROUGH THE DAY. EXPECTED TIMING OF THIS FEATURE WILL
BRING FORCING INTO THE SOUTHERN FA AFTER 18Z...AND INTO THE
NORTHERN FA AFTER 21Z. THIS TIMING IS SLIGHTLY SLOWER COMPARED
WITH FRIDAY...WHICH MAY ALLOW MORE TIME FOR HEATING. DEEP LAYER
SHEAR WILL NOT BE MUCH STRONGER TODAY...AND SEVERE POTENTIAL WILL
DEPEND ON ENHANCED INSTABILITY DUE TO HEATING. AS OF 08Z...LOW
CLOUDS ON THE COOL SIDE OF THE SFC BOUNDARY ARE ADVANCING TO THE
SOUTH/SOUTHEAST. ANTICIPATE THIS SOUTH/SOUTHEAST ADVANCEMENT OF
CLOUDS TO STALL AROUND MID-MORNING FROM AROUND BEMIDJI TO WAHPETON
(FOLLOWING THE HRRR). ALTHOUGH CLOUDS WILL LIKELY REMAIN ACROSS
MUCH OF EASTERN NORTH DAKOTA...THERE IS THE POTENTIAL FOR
CLEARING ACROSS THE MINNESOTA COUNTIES. MOST CAMS INDICATE THE
BEST POTENTIAL FOR SEVERE STORMS WILL BE TOWARD LATE AFTERNOON
ACROSS NW MN (WHERE FORCING WILL ARRIVE LAST...PROVIDING MORE TIME
FOR HEATING AND GREATER INSTABILITY). WITH PWATS NEAR 2 INCHES
EXPECTED...LOCALLY HEAVY RAIN WILL ALSO BE A CONCERN...ALTHOUGH
THE ENTIRE SYSTEM SHOULD BE PROGRESSIVE AND LIMIT THE COVERAGE OF
FLASH FLOOD POTENTIAL. WILL MENTION RW+ ACROSS NW MN WHERE STRONGER
STORMS ARE MORE LIKELY. CONSIDERING THE MANY VARIABLES
INVOLVED...WILL NOT YET MENTION T+.
COLD FRONT WILL MOVE THROUGH THE REGION ON SUNDAY...WITH
THUNDERSTORMS AGAIN POSSIBLE. TIMING WILL DETERMINE SEVERE
POTENTIAL...WITH MOST GUIDANCE SUGGESTING BEST CHANCES EAST OF THE
REGION (ALTHOUGH SPC DID PLACE THE FAR EASTERN FA IN A SLIGHT
RISK).
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 320 AM CDT SAT SEP 5 2015
SUNDAY NIGHT-MONDAY NIGHT...COOL AND DRY AIRMASS WILL BE IN PLACE.
CYCLONIC FLOW ALOFT MAY LEAD TO SOME SHOWERS.
TUESDAY-FRIDAY...PERIOD BEGINS WITH ZONAL FLOW ALOFT AND AN UPPER
WAVE MOVING ACROSS THE NORTHERN TIER WITH ASSOCIATED COLD FRONT.
THIS WILL BRING A CHANCE OF CONVECTION TO PORTIONS OF NORTHWEST
AND W CNTRL MN. LWT THEN MOVES ACROSS MN THU NIGHT INTO FRI WITH
NW FLOW PATTERN SETTING UP FOR THE END OF THE WEEK. SFC HIGH
PRESSURE OVER THE DAKOTAS SHOULD KEEP REGION DRY FROM FRIDAY INTO
THE WEEKEND. DAYTIME HIGHS WILL BE SEASONALLY COOL WITH MAX TEMPS
THU AND FRI STRUGGLING TO REACH THE 70S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 631 AM CDT SAT SEP 5 2015
LIFR CIGS AFFECTING MOST AREAS EARLY THIS MORNING (EXCEPT FARGO).
THESE CIGS WILL GRADUALLY RISE THROUGH THE DAY...OR MOVE NORTH AS
THE NEXT SYSTEM MOVES TOWARD THE REGION. USED HRRR GUIDANCE FOR
TIMING OF CIGS. THUNDERSTORMS EXPECTED THIS AFTERNOON AND EVENING
ACROSS MUCH OF THE REGION.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...TG
LONG TERM...TG/SPEICHER
AVIATION...TG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
611 AM CDT SAT SEP 5 2015
.UPDATE...
ISSUED AT 603 AM CDT SAT SEP 5 2015
FOR MORNING UPDATE HAVE ADJUSTED POPS A BIT TOWARDS CURRENT
TRENDS WHICH SEEM TO BE PICKED UP RATHER WELL BY THE HRRR MODEL.
HEAVIER PRECIPITATION WILL CONTINUE TO PUSH NORTH TOWARDS
CANADA...BUT BEHIND IT A LINE OF SHOWERS/THUNDERSTORMS STRETCHING
SOUTHWARD WILL SHIFT EASTWARD AND FILL IN A BIT. HAVE ALSO BUMPED
UP FOG COVERAGE A BIT OVER SOUTH CENTRAL NORTH DAKOTA INTO THE
JAMES RIVER VALLEY WHERE VISIBILITIES HAVE DIPPED DOWN TO AROUND
1/4 MILE AT TIMES. THE COVERAGE OF THIS IS NOT WIDESPREAD SO WILL
REFRAIN FROM ISSUING AN ADVISORY...BUT WILL COVER WITH A SPECIAL
WEATHER STATEMENT FOR EARLY THIS MORNING.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY AFTERNOON)
ISSUED AT 410 AM CDT SAT SEP 5 2015
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD CONTINUES TO BE
SHOWER AND THUNDERSTORM POTENTIAL.
CURRENTLY...STRONG EMBEDDED S/WV LIFTING NORTH-NORTHEAST INTO
WESTERN NORTH DAKOTA RESPONSIBLE FOR ROBUST CONVECTION NOW MOVING
INTO MY NORTHWEST AND NORTH CENTRAL. THIS ACTIVITY WILL QUICKLY
MOVE NORTH OF THE CANADIAN BORDER BY 12Z. CONTINUED CHANCES FOR
SHOWERS AND THUNDERSTORMS THIS MORNING WEST AHEAD OF AN UPPER
LEVEL JET AND NEAR A QUASI-STATIONARY FRONTAL BOUNDARY.
ONCE AGAIN A WIDE VARIETY OF SOLUTIONS WITH FORECAST QPF FOR
TODAY. HOWEVER...THERE APPEARS TO BE A DECENT ENOUGH CONSENSUS TO
KEEP HIGH POPS CENTRAL INTO EAST THIS MORNING INTO THE AFTERNOON
WITH ANOTHER STRONG EMBEDDED WAVE LIFTING NORTH-NORTHEAST ACROSS
CENTRAL SOUTH DAKOTA THIS MORNING AND INTO EASTERN NORTH DAKOTA
THIS AFTERNOON. FORCING WILL BE ENHANCED AS THE NOSE OF A STRONG
UPPER LEVEL JET PUSHES NORTHEAST INTO THE DAKOTAS. FOCUSED HIGHER
POPS ALONG THE AFOREMENTIONED QUASI-STATIONARY BOUNDARY. STRONG
MOISTURE FEED CONTINUES FROM TROPICAL STORM KEVIN...SO HEAVY
RAINERS WILL ONCE AGAIN BE POSSIBLE TODAY. IN ADDITION...A FEW
STRONGER STORMS ONCE AGAIN POSSIBLE 1-1.5K MUCAPE AND AROUND 35KTS
OF WIND SHEAR.
THE UPPER JET WILL FORCE THE STATIONARY SFC LOW FINALLY OFF TO
OUR NORTH AND EAST THIS EVENING INTO THE OVERNIGHT ALLOWING FOR A
DRY WESTERLY FLOW TO DEVELOP INTO THE WESTERN DAKOTAS AFTER 00Z.
LINGERING PRECIPITATION POSSIBLE EAST WITH BETTER CHANCES
NORTHWEST AND NORTH CENTRAL TONIGHT NEAR THE TRACK OF THE BASE OF
THE WEST COAST TROUGH LIFTING NORTHEAST ACROSS MONTANA AND INTO
SASKATCHEWAN. ALL AREAS SHOULD BE DRY BY SUNDAY AFTERNOON AS THE
DRY WESTERLY FLOW CONTINUES TO EXPAND ACROSS THE NORTHERN PLAINS.
BREEZY BUT PLEASANT FOR SUNDAY AS SFC DEWPOINT TEMPERATURES FALL
FROM THE 60S AND LOW 70S WE HAVE SEEN THE PAST COUPLE OF DAYS
DOWN INTO THE 40S AND LOW 50S BY SUNDAY AFTERNOON.
.LONG TERM...(SUNDAY EVENING THROUGH FRIDAY)
ISSUED AT 345 AM CDT SAT SEP 5 2015
QUIET WEATHER IS EXPECTED SUNDAY NIGHT AS BROAD AREA OF
PRECIPITATION CONTINUES TO LIFT TO THE NORTHEAST. ON
MONDAY...AREA WILL BE UNDER COOL BROAD CYCLONIC FLOW. THIS MAY
LEAD TO SOME SHOWERS DEVELOPING...AND POSSIBLY A WEAK THUNDERSTORM
OR TWO...OVER SOUTH CENTRAL NORTH DAKOTA INTO THE JAMES RIVER
VALLEY. QUIET WEATHER RETURNS IN THE EVENING WITH LOSS OF DAYTIME
HEATING. QUIET WEATHER IS EXPECTED ON MONDAY WITH WEAK RIDGE
PASSING OVER...THOUGH TEMPERATURES WILL REMAIN COOL. THROUGH THE
REMAINDER OF THE WEEK WILL HAVE OCCASIONAL LOW CHANCES FOR
PRECIPITATION AS A VARIETY OF WEAK DISTURBANCES PASS THROUGH.
TEMPERATURES WILL GRADUALLY WARM TOWARDS THE END OF THE WEEK WITH
RIDGING OVER THE WESTERN CONUS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 400 AM CDT SAT SEP 5 2015
IFR-VLIFR STRATUS AND PATCHY FOG DEVELOPING ACROSS ALL TERMINALS
EARLY THIS SATURDAY MORNING AND SHOULD PERSIST THROUGH THE AM
HOURS. SCATTERED SHOWERS AND THUNDERSTORMS ACROSS WESTERN INTO
NORTH CENTRAL NORTH DAKOTA EARLY THIS SATURDAY MORNING...WITH
THIS ACTIVITY CONTINUING/REDEVELOPING CENTRAL INTO EAST LATER
THIS MORNING AND INTO THE AFTERNOON.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JJS
SHORT TERM...NH
LONG TERM...JJS
AVIATION...NH
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
710 AM EDT SAT SEP 5 2015
.SYNOPSIS...
THE UPPER LEVEL DISTURBANCE OVER MICHIGAN WILL WEAKEN AND LIFT
NORTHEAST TODAY. A BROAD AREA OF HIGH PRESSURE OVER NEW ENGLAND WILL
MOVE SOUTH ALONG THE EAST COAST THROUGH THE HOLIDAY WEEKEND. A
WEAKENING FRONT WILL STALL JUST NORTH OF THE AREA ON TUESDAY...THEN
PUSH SOUTH ON WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CLUSTER OF THUNDERSTORMS WITH EFFICIENT RAINFALL RATES DEVELOPED
OVER THE LAST 2 HOURS PRODUCING HEAVY RAINFALL FROM VANLUE TO
FOSTORIA TO NEAR WOODVILLE. STORM MOTION IS VERY SLOW WITH STORMS
BUILDING TO NORTH AT 5-10 MPH. RADAR ESTIMATES THAT SOME AREAS
HAVE ALREADY HAD OVER 2 INCHES OF RAIN AND ARE MONITORING FOR ANY
FLOODING ISSUES. STORMS ARE APPROACHING THE TOLEDO AREA AND HEAVY
RAIN LOOKS TO IMPACT AT LEAST THE EARLY PORTION OF THE MORNING
COMMUTE. IT APPEARS THESE THUNDERSTORMS HAVE DEVELOPED IN AN AREA
OF MOISTURE CONVERGENCE AHEAD OF THE UPPER LEVEL CIRCULATION.
PREVIOUS DISCUSSION...WATER VAPOR IMAGERY STILL SHOWS AN UPPER
LEVEL CIRCULATION CENTERED OVER SOUTHERN LAKE MICHIGAN EARLY THIS
MORNING. A FEW THUNDERSTORMS HAVE BEEN DEVELOPING EARLY THIS
MORNING ACROSS INDIANA AND NW OHIO AHEAD OF THE DRIER AIR WRAPPING
AROUND THE SOUTH SIDE OF THE CIRCULATION. THE RUC SHOWS THIS SPOKE
OF ENERGY WILL TEND TO WEAKEN OVER THE NEXT SEVERAL HOURS. AFTER
THAT MODELS SHOWS THE UPPER LEVEL FEATURE WEAKENING AND SLOWLY
LIFTING NE ACROSS LOWER MICHIGAN THROUGH THE AFTERNOON. EXPECT TO
SEE THE EARLY MORNING CONVECTION IN THE WEST TEND TO WEAKEN
THROUGH 13-14Z THEN WAIT FOR INSTABILITY TO INCREASE THIS
AFTERNOON. COVERAGE OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO BE
LESS THAN THE PAST COUPLE DAYS GIVEN THE WEAKENING UPPER LEVEL
FEATURE. SUFFICIENT INSTABILITY IS EXPECTED TO DEVELOP AGAIN THIS
AFTERNOON WITH POCKETS OF CAPE IN EXCESS OF 2000 J/KG. THERE WILL
BE LESS OF A TRIGGER THIS AFTERNOON WITH BEST CHANCES FOR
INITIATION IN NW OHIO ON THE SOUTHERN FLANK OF THE WAVE AND NE
OHIO ALONG THE LAKE BREEZE. ALTHOUGH SEVERE THUNDERSTORMS ARE
GENERALLY NOT EXPECTED...CAN NOT RULE OUT A WARNING OR TWO AS
STRONG CELLS COLLAPSE. NOT ENOUGH SHEAR FOR ANYTHING MORE
ORGANIZED TODAY.
WITH LESS CLOUD COVER AND PRECIP THAN YESTERDAY...TEMPERATURES WILL
REBOUND INTO THE MID 80S IN PA TO NEAR 90 IN NW OHIO.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
THUNDERSTORMS WILL DIMINISH THIS EVENING WITH HEIGHTS BUILDING ALOFT
ON SUNDAY. THE TREND WILL CONTINUE FOR LESS THUNDERSTORM ACTIVITY
EXCEPT FOR NE OHIO/NW PA WHERE THUNDERSTORMS WILL LIKELY DEVELOP
AGAIN ALONG THE LAKE BREEZE. DEWPOINTS START TO MIX OUT BY MONDAY
AND EXPECT DRY CONDITIONS TO FINALLY PREVAIL WITH THE ATMOSPHERE
BECOMING INCREASINGLY CAPPED.
THE RIDGE ALOFT STARTS TO FLATTEN BY TUESDAY AS THE UPPER TROUGH
APPROACHES THE MIDWEST. GFS IS STILL MORE AGGRESSIVE WITH SHORTWAVE
ENERGY STREAMING NORTHEAST THROUGH THE CENTRAL GREAT LAKES ON
TUESDAY AFTERNOON AHEAD OF THE TROUGH WITH THUNDERSTORMS DEVELOPING.
THE GFS IS AN OUTLIER WITH THIS ENERGY AND OUTPACES THE RETURN OF
THE LOW-LEVEL MOISTURE. EXPECT CONVECTION TO FILL IN TUESDAY NIGHT
AS THE SLOW MOVING FRONTAL BOUNDARY SINKS SOUTH. GIVEN THE SLOWER
TIMING...KEPT HIGHS IN THE UPPER 80S TO NEAR 90 THROUGH TUESDAY.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
BOTH MODELS SIGNALING
CHANGE OF THE CURRENT WEATHER PATTERN MID WEEK. UNFORTUNATELY THE
ECMWF IS COMING INTO LINE WITH THE LATEST GFS. ALTHOUGH GFS A
LITTLE FASTER ON THE TIMING TREND IS STILL THE SAME. MODELS PUSH
COLD FRONT ACROSS THE FORECAST AREA ON WEDNESDAY ONLY TO STALL THE
FRONT ACROSS CENTRAL OHIO...WITH LOW PRESSURE MOVING ACROSS THE
LOWER LAKES BY THE END OF THE WORK WEEK. MEANWHILE AT THE UPPER
LEVELS NICE UPPER RIDGE WILL GRADUALLY BE REPLACED BY A DIGGING
TROUGH BY THIS TIME NEXT WEEK.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
CONVECTION FROM NW OH INTO THE WESTERN BASIN WILL DISSIPATE BY MID
MORNING. EXPECT ISOLATED TO SCATTED TSRA TO REDEVELOP LATE THIS
AFTERNOON. BEST CHANCE AGAIN APPEARS TO BE NW OHIO. ADDED VCTS
LATE THIS AFTERNOON FOR TOL AND FDY.
OUTLOOK...AREAS OF NON VFR EACH MORNING IN FOG AND HAZE.
&&
.MARINE...
QUIET WEATHER WILL CONTINUE ON THE LAKE THROUGH THE
WEEKEND...ALTHOUGH A CHANCE OF THUNDERSTORM ACTIVITY IS POSSIBLE
THIS AFTERNOON. SOUTHWEST FLOW WILL DEVELOP ON THE LAKE EARLY IN
THE WORK WEEK AHEAD OF SLOW MOVING COLD FRONT. MODELS CONTINUE TO
HOLD OFF THE NEXT FRONT UNTIL WEDNESDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KEC
NEAR TERM...KEC
SHORT TERM...KEC
LONG TERM...DJB
AVIATION...DJB
MARINE...DJB
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
648 AM EDT SAT SEP 5 2015
.SYNOPSIS...
THE UPPER LEVEL DISTURBANCE OVER MICHIGAN WILL WEAKEN AND LIFT
NORTHEAST TODAY. A BROAD AREA OF HIGH PRESSURE OVER NEW ENGLAND WILL
MOVE SOUTH ALONG THE EAST COAST THROUGH THE HOLIDAY WEEKEND. A
WEAKENING FRONT WILL STALL JUST NORTH OF THE AREA ON TUESDAY...THEN
PUSH SOUTH ON WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CLUSTER OF THUNDERSTORMS WITH EFFICIENT RAINFALL RATES DEVELOPED
OVER THE LAST 2 HOURS PRODUCING HEAVY RAINFALL FROM VANLUE TO
FOSTORIA TO NEAR WOODVILLE. STORM MOTION IS VERY SLOW WITH STORMS
BUILDING TO NORTH AT 5-10 MPH. RADAR ESTIMATES THAT SOME AREAS
HAVE ALREADY HAD OVER 2 INCHES OF RAIN AND ARE MONITORING FOR ANY
FLOODING ISSUES. STORMS ARE APPROACHING THE TOLEDO AREA AND HEAVY
RAIN LOOKS TO IMPACT AT LEAST THE EARLY PORTION OF THE MORNING
COMMUTE. IT APPEARS THESE THUNDERSTORMS HAVE DEVELOPED IN AN AREA
OF MOISTURE CONVERGENCE AHEAD OF THE UPPER LEVEL CIRCULATION.
PREVIOUS DISCUSSION...WATER VAPOR IMAGERY STILL SHOWS AN UPPER
LEVEL CIRCULATION CENTERED OVER SOUTHERN LAKE MICHIGAN EARLY THIS
MORNING. A FEW THUNDERSTORMS HAVE BEEN DEVELOPING EARLY THIS
MORNING ACROSS INDIANA AND NW OHIO AHEAD OF THE DRIER AIR WRAPPING
AROUND THE SOUTH SIDE OF THE CIRCULATION. THE RUC SHOWS THIS SPOKE
OF ENERGY WILL TEND TO WEAKEN OVER THE NEXT SEVERAL HOURS. AFTER
THAT MODELS SHOWS THE UPPER LEVEL FEATURE WEAKENING AND SLOWLY
LIFTING NE ACROSS LOWER MICHIGAN THROUGH THE AFTERNOON. EXPECT TO
SEE THE EARLY MORNING CONVECTION IN THE WEST TEND TO WEAKEN
THROUGH 13-14Z THEN WAIT FOR INSTABILITY TO INCREASE THIS
AFTERNOON. COVERAGE OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO BE
LESS THAN THE PAST COUPLE DAYS GIVEN THE WEAKENING UPPER LEVEL
FEATURE. SUFFICIENT INSTABILITY IS EXPECTED TO DEVELOP AGAIN THIS
AFTERNOON WITH POCKETS OF CAPE IN EXCESS OF 2000 J/KG. THERE WILL
BE LESS OF A TRIGGER THIS AFTERNOON WITH BEST CHANCES FOR
INITIATION IN NW OHIO ON THE SOUTHERN FLANK OF THE WAVE AND NE
OHIO ALONG THE LAKE BREEZE. ALTHOUGH SEVERE THUNDERSTORMS ARE
GENERALLY NOT EXPECTED...CAN NOT RULE OUT A WARNING OR TWO AS
STRONG CELLS COLLAPSE. NOT ENOUGH SHEAR FOR ANYTHING MORE
ORGANIZED TODAY.
WITH LESS CLOUD COVER AND PRECIP THAN YESTERDAY...TEMPERATURES WILL
REBOUND INTO THE MID 80S IN PA TO NEAR 90 IN NW OHIO.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
THUNDERSTORMS WILL DIMINISH THIS EVENING WITH HEIGHTS BUILDING ALOFT
ON SUNDAY. THE TREND WILL CONTINUE FOR LESS THUNDERSTORM ACTIVITY
EXCEPT FOR NE OHIO/NW PA WHERE THUNDERSTORMS WILL LIKELY DEVELOP
AGAIN ALONG THE LAKE BREEZE. DEWPOINTS START TO MIX OUT BY MONDAY
AND EXPECT DRY CONDITIONS TO FINALLY PREVAIL WITH THE ATMOSPHERE
BECOMING INCREASINGLY CAPPED.
THE RIDGE ALOFT STARTS TO FLATTEN BY TUESDAY AS THE UPPER TROUGH
APPROACHES THE MIDWEST. GFS IS STILL MORE AGGRESSIVE WITH SHORTWAVE
ENERGY STREAMING NORTHEAST THROUGH THE CENTRAL GREAT LAKES ON
TUESDAY AFTERNOON AHEAD OF THE TROUGH WITH THUNDERSTORMS DEVELOPING.
THE GFS IS AN OUTLIER WITH THIS ENERGY AND OUTPACES THE RETURN OF
THE LOW-LEVEL MOISTURE. EXPECT CONVECTION TO FILL IN TUESDAY NIGHT
AS THE SLOW MOVING FRONTAL BOUNDARY SINKS SOUTH. GIVEN THE SLOWER
TIMING...KEPT HIGHS IN THE UPPER 80S TO NEAR 90 THROUGH TUESDAY.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
BOTH MODELS SIGNALING
CHANGE OF THE CURRENT WEATHER PATTERN MID WEEK. UNFORTUNATELY THE
ECMWF IS COMING INTO LINE WITH THE LATEST GFS. ALTHOUGH GFS A
LITTLE FASTER ON THE TIMING TREND IS STILL THE SAME. MODELS PUSH
COLD FRONT ACROSS THE FORECAST AREA ON WEDNESDAY ONLY TO STALL THE
FRONT ACROSS CENTRAL OHIO...WITH LOW PRESSURE MOVING ACROSS THE
LOWER LAKES BY THE END OF THE WORK WEEK. MEANWHILE AT THE UPPER
LEVELS NICE UPPER RIDGE WILL GRADUALLY BE REPLACED BY A DIGGING
TROUGH BY THIS TIME NEXT WEEK.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
LITTLE CHANGE IN WEATHER PATTERN. AREAS OF MVFR BR TOWARD
DAYBREAK WITH ISOLATED CONVECTION THIS AFTERNOON. DO NOT THINK
THERE WILL BE AS MUCH CONVECTION THIS AFTERNOON AS YDY.
OUTLOOK...AREAS OF NON VFR EACH MORNING IN FOG AND HAZE.
&&
.MARINE...
QUIET WEATHER WILL CONTINUE ON THE LAKE THROUGH THE
WEEKEND...ALTHOUGH A CHANCE OF THUNDERSTORM ACTIVITY IS POSSIBLE
THIS AFTERNOON. SOUTHWEST FLOW WILL DEVELOP ON THE LAKE EARLY IN
THE WORK WEEK AHEAD OF SLOW MOVING COLD FRONT. MODELS CONTINUE TO
HOLD OFF THE NEXT FRONT UNTIL WEDNESDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KEC
NEAR TERM...KEC
SHORT TERM...KEC
LONG TERM...DJB
AVIATION...DJB
MARINE...DJB
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
731 AM EDT SAT SEP 5 2015
.SYNOPSIS...
HIGH PRESSURE WILL ENSURE MAINLY DRY WEATHER FOR LABOR DAY
WEEKEND WITH ABOVE NORMAL WARMTH AND JUST THE CHANCE OF AN
AFTERNOON OR EVENING POP-UP SHOWER OR THUNDERSTORM. THE PATTERN
WILL START TO CHANGE IN THE MIDDLE OF THE WEEK AS THE UPPER LEVEL
FLOW FLATTENS OUT AND A COLD FRONT DROPS DOWN FROM THE NORTH.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SHOWERS HAVE BEEN PERSISTENT IN THE SRN TIER THROUGH THE NIGHT.
THE WIND SHIFT/WEAK CONVERGENCE AND DEEP EASTERLY MOISTURE INFLUX
ARE PROBABLY DRIVING THESE SHOWERS SINCE DIURNAL INSTABILITY HAS
LONG SINCE DISAPPEARED. ONLY LIGHT SHOWERS /NO T/ LEFT IN THE SC
MTNS. HRRR AND RAP MOVE THESE SLIGHTLY TO THE WEST BEFORE KILLING
THEM OFF JUST AFTER SUNRISE. LOW CLOUDS HAVE OVERSPREAD/DEVELOPED
OVER THE ENTIRE REGION EXCEPT FOR WARREN CO. A FEW PATCHES OF
CLEAR EAST OF KIPT CAN BE IMAGINED WHEN PERUSING THE 11-3.9
MICRON IMAGERY THIS MORNING. OTHERWISE...IT IS CLOUDY. THESE
CLOUDS COULD BE TOUGH TO MIX OUT - AT LEAST IN A RAPID FASHION -
SINCE THEY ARE GENERALLY ABOVE 1KFT. THUS...WILL HANG ONTO SOME OF
THESE CLOUDS INTO THE MID TO LATE MORNING. THE EAST WILL BE
BREAKING OUT INTO THE SUN AND THE MIXING IN THE WEST COULD ALLOW A
SHOWER OR TWO TO DEVELOP IN THE AFTN. HOWEVER...MOST OF THESE WILL
REMAIN WEST OF THE CWA. ONLY THE NW IS WORTHY OF A CHC POP FOR
LATE THIS AFTN/THIS EVENING AS A LAKE BREEZE MAY KICK OFF A FEW
SHRA. THE CLOUDS WILL MAKE IT MORE DIFFICULT TO GET TO THE LOFTY
MAXES WE HAVE EXPERIENCED RECENTLY - INCLUDING TIES OF THE RECORD
HIGHS AT HARRISBURG...ALTOONA AND BRADFORD YESTERDAY. WILL GO FOR
MAXES BASED ON AN EQUAL BLEND OF MOS GUIDANCE MINUS ONE OR TWO
DEGS. THIS WILL RESULT IN ONLY A 10 DEGREE DIURNAL SWING AT MANY
PLACES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
THE UPPER LOW OVER THE UPPER GREAT LAKES WILL SLOLY FILL AND LOSE
CHARACTER. THE SFC HIGH WILL STILL NOSE INTO THE STATE...BUT THE
CENTER OF IT WILL SLIDE SOUTH INTO THE WESTERN ATLANTIC BY
MONDAY. ANY SHOWERS THIS EVENING WILL LIKELY BE IN THE NW...BUT
THE EXPECTED CELL MOTION SHOULD KEEP THEM EITHER OUT OF THE STATE
TO THE NORTH OR MAKE THE FEW THAT DO POP UP GO SLOWLY TO THE NORTH
AND OUT OF THE AREA EARLY THIS EVENING. THE LOW CLOUDS WILL
PROBABLY TRY TO REDEVELOP IN THE ERN MTNS. OTHER AREAS MAY SEE
THEM TRY TO FORM...BUT WILL KEEP IT GENERALLY P/C OVERNIGHT WITH
THE CLEARING PERHAPS ALLOWING FOR SOME MORNING FOG ON SUNDAY.
SUNDAY LOOKS TO BE DRIER AND SUNNIER...AND POPS ALMOST NON-
EXISTENT. TEMPS WILL GET A FEW DEGS F WARMER VS SATURDAY. ONCE
AGAIN...IT WILL BE THE FAR NW WHICH COULD SEE A POP UP SHOWER -
PERHAPS AGAIN BEING GENERATED ALONG A LAKE BREEZE BOUNDARY.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
THE HIGH PRESSURE WILL KEEP IT WARM AND MAINLY DRY INTO MONDAY.
A WEAK COLD FRONT WILL SLIDE SLOWLY TO THE ESE FROM THE GREAT
LAKES/MIDWEST STATES. THIS FEATURE COULD BRING SOME ISOLATED
SHRA/TSRA TO OUR NW ZONES BEGINNING TUESDAY AFTERNOON AND EVENING.
A SLOWLY AMPLIFYING BROAD TROUGH FROM THE NRN PLAINS THROUGH THE
NE U.S. WEDNESDAY AFTERNOON INTO NEXT WEEKEND WILL PUSH A
SECOND...STRONGER CFRONT EAST ACROSS THE COMMONWEALTH WEDNESDAY
NIGHT AND THURSDAY.
THIS PATTERN TRANSITION WILL BRING A FEW OPPORTUNITIES FOR
SHOWERS AND THUNDERSTORMS...ALBEIT MAINLY OF THE SCATTERED
AFTERNOON AND EVENING VARIETY.
12Z GEFS AND 12Z EC ARE IN GOOD AGREEMENT ON THE LOCATION OF THIS
TROUGH AXIS /FROM LAKE SUPERIOR TO THE MID MISS VALLEY AT 00Z
SAT/...THOUGH AS ONE WOULD EXPECT...THE ENSEMBLE MEAN DAMPENS OUT
THE AMPLITUDE OF THE TROUGH COMPARED TO THE EC.
DETAILS IN THE TIMING OF ANY SPECIFIC SHORTWAVES ROTATING THROUGH
THIS AMPLIFYING TROUGH ARE SIMPLY TOO MUDDY AT THIS TIME RANGE.
ONE THING MORE CERTAIN IN THIS MEDIUM RANGE FORECAST IS THE COOLING
TEMPS FOR THE LATTER HALF OF THE WEEK AND NEXT WEEKEND...WHEN BOTH
MAX AND MIN TEMPS COULD BE UP TO SEVERAL DEG F BELOW NORMAL
/ESPECIALLY OVER THE NRN AND WESTERN MTNS OF THE STATE...WHERE MORE
CLOUDS AND COOLER TEMPS ALOFT WILL BE FOUND/.
&&
.AVIATION /11Z SATURDAY THROUGH WEDNESDAY/...
11.3.9U IMAGERY AT 11Z SHOWS STRATUS HAS BECOME WIDESPREAD ACROSS
CENTRAL PA...THE RESULT OF MOIST SERLY FLOW AND OROGRAPHIC
LIFTING. BLEND OF LATEST HRRR/SFC OBS SUGGEST IFR CIGS ARE LIKELY
BTWN 12Z-13Z AT KBFD/KJST AND POSSIBLE AT KAOO. LOWER ELEVATIONS
FURTHER EAST SHOULD FARE BETTER WITH MVFR CIGS EXPECTED.
DIURNAL HEATING/MIXING WILL CAUSE CIGS TO RISE BY LATE AM. MDL
SOUNDINGS INDICATE MVFR CIGS MAY LINGER ACROSS THE CENTRAL MTNS
UNTIL ARND NOON. HOWEVER...BY AFTN THERE IS A HIGH DEGREE OF
CONFIDENCE IN WIDESPREAD VFR CONDS AND LIGHT WIND.
MOSTLY CLEAR SKIES AND A LIGHT WIND WILL LIKELY RESULT IN PATCHY
VALLEY FOG AGAIN EARLY SUNDAY MORNING.
OUTLOOK...
SUN-TUE...PATCHY FOG IN THE MORNING...OTHERWISE VFR.
WED...ISOLD PM TSRA IMPACTS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...LAMBERT
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1015 AM CDT SAT SEP 5 2015
.DISCUSSION...A FEW CHANGES TO THE PREVIOUS FORECAST...MAINLY DEW
POINTS WHICH WERE TOO LOW IN A FEW LOCATIONS. STILL...GIVEN THE
UPDATED VALUES...HEAT INDICES BETWEEN 105 AND 109 ARE BEING
FORECAST (SPS HAS BEEN SENT OUT). WILL MONITOR AS THIS IS THE
LABOR DAY WEEKEND SO WILL HAVE TO KEEP A KEENER EYE ON THIS.
BOUNDARY LAYER WINDS A BIT HIGHER TODAY AND THE RIDGE A BIT
STRONGER...FEEL CONVECTION THIS AFTERNOON WILL BE MORE LIMITED AND
MAINLY OVER THE NORTHERN AREAS BEFORE ENDING BY LATE AFTERNOON.
THIS KIND OF FOLLOWS WHAT THE HRRR AND NSSL MODELS ARE INDICATING
SO ADJUSTED AFTERNOON POPS ACCORDINGLY. HIGH TEMPERATURE FORECAST
LOOKS REASONABLE. ADJUSTED CLOUD COVER TOO. MINOR ADJUSTMENTS TO
SECOND PERIOD TO ACCOUNT FOR FIRST PERIOD CHANGES. NO OTHER
UPDATES FOR OTHER PERIODS AT THIS TIME.
&&
.PREV DISCUSSION... /ISSUED 638 AM CDT SAT SEP 5 2015/
DISCUSSION...UPDATED FOR 12Z AVIATION.
AVIATION...POCKETS OF PATCHY FOG AND LOW CLOUDS HAVE DEVELOPED
THIS MORNING AND COULD IMPACT ALI/VCT/LRD FOR THE NEXT COUPLE OF
HOURS. ALSO...ISOLATED SHOWERS HAVE DEVELOPED NORTH OF PORT
ARANSAS INTO THE NORTHERN COASTAL BEND AND WILL CONTINUE TO MOVE
INLAND THIS MORNING. ONLY HAVE INCLUDED VCSH REMARKS FOR THE VCT
TERMINAL AS CONFIDENCE IS LOW TO MENTION PRECIP REMARKS AT THE
OTHER TERMINALS. WINDS WILL BE PREDOMINANTLY OUT OF THE SSE AND SE
WITH GUSTS AOA 20 KNOTS IN THE AFTERNOON. ANOTHER ROUND OF LOW
CLOUDS MAY DEVELOP LATE TONIGHT AND HAVE MENTIONED MVFR CIGS AT
ALI/VCT/CRP.
PREV DISCUSSION... /ISSUED 345 AM CDT SAT SEP 5 2015/
SHORT TERM (TODAY THROUGH SUNDAY)...UPPER LEVEL RIDGE WILL
BUILD OVER SOUTH TEXAS TODAY INTO SUNDAY. MOISTURE WILL BE A
LITTLE LESS TODAY AS MODELS PROG PW VALUES BETWEEN 1.7 TO 1.9
INCHES. ISOLATED CONVECTION OVER THE MARINE WATERS MAY APPROACH
THE COAST LATER THIS MORNING. THEN...DAYTIME HEATING COMBINED WITH
THE SEA BREEZE MAY BE ENOUGH TO GENERATE ISOLATED TO POSSIBLY
SCATTERED SHOWERS AND A FEW STORMS. LAST FEW RUNS OF THE HRRR AT
LEAST SUPPORT THIS TO SOME EXTENT...AND HAVE KEPT 20 POPS ACROSS
THE EAST WITH SOME 30 POPS ACROSS THE VICTORIA CROSSROADS.
CONDITIONS SHOULD BE A LITTLE WARMER TODAY COMPARED TO YESTERDAY
AS HIGHS CLIMB INTO THE LOWER 100S OUT WEST...TO MID/LOWER 90S
ACROSS THE EAST AND NORTHEAST. MOISTURE DECREASES A LITTLE MORE ON
SUNDAY AND GUIDANCE IS NOT TOO OPTIMISTIC ABOUT RAIN CHANCES. WILL
LEAVE RAIN CHANCES OUT OF THE FORECAST FOR NOW. ABOVE NORMAL
TEMPERATURES WILL CONTINUE ON SUNDAY.
LONG TERM (SUNDAY NIGHT THROUGH FRIDAY)...CHANGES IN THE UPPER
PATTERN TAKE PLACE BY SUNDAY NIGHT WITH H5 RIDGE FLATTENS AND SLIDES
WEST AS A TROUGH SWINGS EAST ACROSS THE HIGH PLAINS AND A WEAK CUT
OFF LOW DRIFTS WEST ALONG ACROSS THE GULF STATES INTO THE WESTERN
GULF. MODELS DISAGREE ON THE AMOUNT OF MOISTURE AVAILABLE...BUT
OVERALL...A RELATIVE INCREASE IN MOISTURE MOVES INTO THE WESTERN
GULF AS WELL AS THE EASTERN HALF OF THE CWA...AND IS DRAWN NORTH
INTO THE CENTRAL PLAINS. WITH WEAKNESS ALOFT AND SLIGHTLY COOL H85-
H7 TEMPS...DAILY CONVECTION IS EXPECTED THROUGH THE WEEK IN THE FORM
OF SHOWERS IN THE MORNING ACROSS THE GULF...MOVING INLAND WITH
HEATING. THE GFS AND EURO BOTH HINT AT A SURFACE FRONT TO MOVE
THROUGH THE CENTRAL PLAINS AND PUSH SOUTH INTO TEXAS. DISAGREEMENTS
DEVELOP BETWEEN THE LONG TERM MODELS ON THE DEVELOPMENT AND TIMING
OF THE FRONT FROM THURSDAY AND ONWARD. THIS SAID...MAINLY KEPT
SLIGHT CHANCE POPS FROM MONDAY THROUGH WEDNESDAY FOR ISOLATED
ACTIVITY ACROSS THE NORTHERN COASTAL BEND AND COASTAL PLAINS...WITH
20-30 POPS INTRODUCED BY FRIDAY DUE TO PROXIMITY OF THE BOUNDARY.
TEMPERATURES FOR THE MOST PART WILL BE SLIGHTLY ABOVE NORMAL THROUGH
MUCH OF THE WEEK...WITH COOLER TEMPS TOWARD THE LATER OF THE WORK
WEEK MAINLY DUE TO THE INCREASED CLOUD COVERAGE AND RAIN CHANCES.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 94 79 94 77 94 / 20 10 10 10 20
VICTORIA 94 76 96 75 95 / 30 10 10 10 20
LAREDO 102 79 102 77 102 / 10 10 0 0 10
ALICE 97 76 98 75 98 / 20 10 10 10 10
ROCKPORT 91 80 91 79 90 / 30 10 10 10 20
COTULLA 101 77 101 75 102 / 10 10 0 0 10
KINGSVILLE 96 78 97 76 97 / 20 10 10 10 10
NAVY CORPUS 90 80 90 80 90 / 20 10 10 10 20
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
GW/86...SHORT TERM
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
638 AM CDT SAT SEP 5 2015
.DISCUSSION...UPDATED FOR 12Z AVIATION.
&&
.AVIATION...POCKETS OF PATCHY FOG AND LOW CLOUDS HAVE DEVELOPED
THIS MORNING AND COULD IMPACT ALI/VCT/LRD FOR THE NEXT COUPLE OF
HOURS. ALSO...ISOLATED SHOWERS HAVE DEVELOPED NORTH OF PORT
ARANSAS INTO THE NORTHERN COASTAL BEND AND WILL CONTINUE TO MOVE
INLAND THIS MORNING. ONLY HAVE INCLUDED VCSH REMARKS FOR THE VCT
TERMINAL AS CONFIDENCE IS LOW TO MENTION PRECIP REMARKS AT THE
OTHER TERMINALS. WINDS WILL BE PREDOMINANTLY OUT OF THE SSE AND SE
WITH GUSTS AOA 20 KNOTS IN THE AFTERNOON. ANOTHER ROUND OF LOW
CLOUDS MAY DEVELOP LATE TONIGHT AND HAVE MENTIONED MVFR CIGS AT
ALI/VCT/CRP.
&&
.PREV DISCUSSION... /ISSUED 345 AM CDT SAT SEP 5 2015/
SHORT TERM (TODAY THROUGH SUNDAY)...UPPER LEVEL RIDGE WILL
BUILD OVER SOUTH TEXAS TODAY INTO SUNDAY. MOISTURE WILL BE A
LITTLE LESS TODAY AS MODELS PROG PW VALUES BETWEEN 1.7 TO 1.9
INCHES. ISOLATED CONVECTION OVER THE MARINE WATERS MAY APPROACH
THE COAST LATER THIS MORNING. THEN...DAYTIME HEATING COMBINED WITH
THE SEA BREEZE MAY BE ENOUGH TO GENERATE ISOLATED TO POSSIBLY
SCATTERED SHOWERS AND A FEW STORMS. LAST FEW RUNS OF THE HRRR AT
LEAST SUPPORT THIS TO SOME EXTENT...AND HAVE KEPT 20 POPS ACROSS
THE EAST WITH SOME 30 POPS ACROSS THE VICTORIA CROSSROADS.
CONDITIONS SHOULD BE A LITTLE WARMER TODAY COMPARED TO YESTERDAY
AS HIGHS CLIMB INTO THE LOWER 100S OUT WEST...TO MID/LOWER 90S
ACROSS THE EAST AND NORTHEAST. MOISTURE DECREASES A LITTLE MORE ON
SUNDAY AND GUIDANCE IS NOT TOO OPTIMISTIC ABOUT RAIN CHANCES. WILL
LEAVE RAIN CHANCES OUT OF THE FORECAST FOR NOW. ABOVE NORMAL
TEMPERATURES WILL CONTINUE ON SUNDAY.
LONG TERM (SUNDAY NIGHT THROUGH FRIDAY)...CHANGES IN THE UPPER
PATTERN TAKE PLACE BY SUNDAY NIGHT WITH H5 RIDGE FLATTENS AND SLIDES
WEST AS A TROUGH SWINGS EAST ACROSS THE HIGH PLAINS AND A WEAK CUT
OFF LOW DRIFTS WEST ALONG ACROSS THE GULF STATES INTO THE WESTERN
GULF. MODELS DISAGREE ON THE AMOUNT OF MOISTURE AVAILABLE...BUT
OVERALL...A RELATIVE INCREASE IN MOISTURE MOVES INTO THE WESTERN
GULF AS WELL AS THE EASTERN HALF OF THE CWA...AND IS DRAWN NORTH
INTO THE CENTRAL PLAINS. WITH WEAKNESS ALOFT AND SLIGHTLY COOL H85-
H7 TEMPS...DAILY CONVECTION IS EXPECTED THROUGH THE WEEK IN THE FORM
OF SHOWERS IN THE MORNING ACROSS THE GULF...MOVING INLAND WITH
HEATING. THE GFS AND EURO BOTH HINT AT A SURFACE FRONT TO MOVE
THROUGH THE CENTRAL PLAINS AND PUSH SOUTH INTO TEXAS. DISAGREEMENTS
DEVELOP BETWEEN THE LONG TERM MODELS ON THE DEVELOPMENT AND TIMING
OF THE FRONT FROM THURSDAY AND ONWARD. THIS SAID...MAINLY KEPT
SLIGHT CHANCE POPS FROM MONDAY THROUGH WEDNESDAY FOR ISOLATED
ACTIVITY ACROSS THE NORTHERN COASTAL BEND AND COASTAL PLAINS...WITH
20-30 POPS INTRODUCED BY FRIDAY DUE TO PROXIMITY OF THE BOUNDARY.
TEMPERATURES FOR THE MOST PART WILL BE SLIGHTLY ABOVE NORMAL THROUGH
MUCH OF THE WEEK...WITH COOLER TEMPS TOWARD THE LATER OF THE WORK
WEEK MAINLY DUE TO THE INCREASED CLOUD COVERAGE AND RAIN CHANCES.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 94 79 94 77 94 / 20 10 10 10 20
VICTORIA 94 76 96 75 95 / 30 10 10 10 20
LAREDO 102 79 102 77 102 / 10 10 0 0 10
ALICE 97 76 98 75 98 / 20 10 10 10 10
ROCKPORT 91 80 91 79 90 / 30 10 10 10 20
COTULLA 101 77 101 75 102 / 10 10 0 0 10
KINGSVILLE 96 78 97 76 97 / 20 10 10 10 10
NAVY CORPUS 90 80 90 80 90 / 20 10 10 10 20
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
TB/78...AVIATION
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
747 AM EDT SAT SEP 5 2015
.SYNOPSIS...
A BACKDOOR COLD FRONT WILL DRIFT INTO FAR SOUTHWEST VIRGINIA AND
NORTHWEST NORTH CAROLINA BY EVENING AND STALL AS SURFACE HIGH
PRESSURE BUILDS SOUTHWESTWARD FROM THE NORTHERN MID-
ATLANTIC...ALLOWING FOR COOLER CONDITIONS TODAY AND CONFINING
THUNDERSTORMS TO WESTERN AREAS. LOW PRESSURE ALOFT WILL LINGER
ACROSS THE SOUTHEAST STATES OVER THE NEXT SEVERAL DAYS ALLOWING
WARM AND HUMID CONDITIONS ALONG WITH SCATTERED SHOWERS AND
THUNDERSTORMS TO RETURN TO THE ENTIRE AREA BY EARLY NEXT WEEK. A
STRONGER COLD FRONT WILL ARRIVE LATE NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 745 AM EDT SATURDAY...
PER HRRR...LIGHT TO MODERATE RAIN SHOWERS NOW DEVELOPING ALONG THE
LEADING EDGE OF THE ADVANCING BACKDOOR FRONT/WEDGE BOUNDARY NEAR
THE BLUE RIDGE. PREVIOUS POPS GENERALLY WELL ACCOUNTED FOR
THIS...BUT HAVE NUDGED THEM UP SLIGHTLY FURTHER EAST TO ACCOUNT
FOR THIS LATEST DEVELOPMENT. THIS ACTIVITY WILL ADVECT WEST TOWARD
THE ALLEGHANYS BY LATE MORNING/AFTERNOON...AT WHICH POINT SOME
THUNDERSTORMS WILL ALSO BEGIN TO DEVELOP ON THE EDGE OF THE
WEDGE/COOLER AIR. WIDESPREAD LOW CLOUDS ALSO DEVELOPING BEHIND THE
BACKDOOR FRONT AND EXTEND WELL NORTH INTO NORTHERN VA AND EAST
TOWARD THE COAST. HAVE INCREASED CLOUD COVER TO MOSTLY CLOUDY
THROUGHOUT THE DAY NEARLY ALL AREAS. NO SIGNIFICANT CHANGES TO
TEMPERATURE OR DEWPOINT READINGS NEEDED AT THIS TIME.
AS OF 415 AM EDT SATURDAY...
A CONVECTIVE OUTFLOW BOUNDARY FROM FRIDAY EVENING WIDESPREAD
THUNDERSTORM ACTIVITY APPEARS TO BE IN PLACE ACROSS FAR SOUTHWEST
VA/EASTERN TN/WESTERN NC...BUT THE TRUE BACKDOOR FRONT IS EVIDENT
JUST EAST OF THE BLUE RIDGE. NEAR THIS BACKDOOR FRONTAL
BOUNDARY...SPOTTY SHOWERS HAVE CONTINUED TO DEVELOP THROUGHOUT THE
NIGHT. HRRR AND LOCAL WRF MODELS SUPPORT A CONTINUATION OF THIS
PATTERN INTO THE MORNING...SHIFTING FURTHER WEST BY AFTERNOON. AT
THAT POINT...SUFFICIENT INSTABILITY WILL BE PRESENT FOR MORE
THUNDERSTORMS. CURRENT THINKING IS THAT A MORE STABLE AIR MASS
WILL SPREAD ACROSS THE PIEDMONT AND TOWARD THE ALLEGHANY FRONT BY
AFTERNOON...CONFINING THUNDERSTORMS TO THE I-77 CORRIDOR AND
POINTS WEST.
WITH A HEALTHY MARITIME EASTERLY FLOW DEVELOPING ACROSS AREAS
EAST OF THE ALLEGHANY FRONT IN THE WAKE OF THE BACKDOOR
FRONT...WIDESPREAD LOW CLOUDS ARE EXPECTED TO DEVELOP AND PERSIST
THROUGH MUCH OF THE DAY. THIS IS ALREADY EVIDENT ON THE LATEST
SATELLITE IMAGES. THESE CLOUDS WILL RESULT IN CONSIDERABLY COOLER
TEMPERATURES THAN WE HAVE SEEN IN RECENT DAYS ACROSS EASTERN PARTS
OF THE CWA...ESPECIALLY THE PIEDMONT WITH MAX AFTERNOON
TEMPERATURES STRUGGLING TO RISE OUT OF THE 70S...SOME 10-15
DEGREES COOLER THAN THE LAST SEVERAL DAYS. WEST OF THE I-77
CORRIDOR...TEMPERATURES ARE STILL EXPECTED TO BE QUITE WARM AND
NEAR TO ABOVE NORMAL...WITH AFTERNOON MAX TEMPS WELL INTO THE 80S
IN LOWER ELEVATIONS TOWARD THE TN BORDER...WITH 70S ACROSS THE
WESTERN MOUNTAINS.
THE WEDGE WILL PEAK OVERNIGHT AND INTO SUNDAY. LOW CLOUDS ARE
EXPECTED TO PERSIST INTO SUNDAY MORNING...WHICH WILL HOLD MIN
TEMPS CLOSER TO NORMAL VALUES FOR EARLY SEPTEMBER. ONLY LIMITED
SHOWER ACTIVITY IS EXPECTED OVERNIGHT IN THE FAR SOUTHWEST. CANNOT
COMPLETELY RULE OUT SOME LIGHT DRIZZLE ON THE EAST SIDE OF THE
ALLEGHANY FRONT (BCB-LWB AREA) EARLY SUNDAY...BUT NOT ENOUGH
CONFIDENCE TO INCLUDE IN THE GRIDS AT THIS TIME. FOG DEVELOPMENT
SUN MORNING SHOULD BE LIMITED BECAUSE OF CLOUDS AND WIDESPREAD
EASTERLY LOW-LEVEL FLOW.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
AS OF 300 AM EDT SATURDAY...
A PRETTY IMPRESSIVE HYBRID WEDGE FOR AUGUST WILL REMAIN OVER THE
EAST COAST SUNDAY...STRETCHING FROM NEW ENGLAND SOUTH INTO GEORGIA.
MODELS ARE USHERING IN MORE DRIER AIR WITH THE 00Z RUN...PLACING
HIGHER RAINFALL AMOUNTS OF A TENTH OF AN INCH /0.10/ OR MORE OVER
NORTH CAROLINA AND SOUTH. THE INTERACTION OF THE WEDGE BOUNDARY AND
A BROAD BUT WEAK UPPER LEVEL LOW OVER THE SOUTHEASTERN USA WILL KEEP
THE STRONGER CONVECTION OUT OF THE AREA. WE STILL CAN NOT RULE OUT
SOME SHOWERS AND THUNDERSTORMS AS WEAK IMPULSES TRACK AROUND THIS
LOW AND OVER THE AREA. THE COMBINATION OF EASTERLY FLOW AND A
STRONGER WEDGE WILL KEEP TEMPERATURES COOLER THAN NORMAL ALONG AND
EAST OF THE BLUE RIDGE SUNDAY AFTERNOON. DOWNSLOPE FLOW WILL HELP
WARM THE WEST WITH TEMPERATURES RUNNING ABOVE NORMAL. THE OVERALL
TEMPERATURE PICTURE FOR THE AREA WILL BE UNIFORM WITH SUNDAY`S
AFTERNOON HIGHS RANGING FROM THE UPPER 70S TO LOWER 80S.
ON MONDAY...THE PARENT HIGH OVER NEW ENGLAND WILL DRIFT
EAST...LEAVING A RESIDUAL BAGGY HIGH OVER THE MID ATLANTIC REGION.
MEANWHILE...THE UPPER LEVEL LOW RETROGRADES WEST ACROSS THE GULF
STATES. WITH THE DEPARTURE OF THE TWO MAIN WEATHER
FEATURES...AFTERNOON HEATING WILL GENERATE SCATTERED SHOWERS AND
THUNDERSTORMS OVER THE MOUNTAINS DURING THE AFTERNOON. THESE SLOW
MOVING STORMS COULD PRODUCE LOCALIZED HEAVY DOWNPOURS. THESE SHOWERS
WILL FADE WITH LOSE OF HEATING. MORE SUN IS EXPECTED MONDAY WHICH
WILL LEAD TO TEMPERATURES RETURNING TO NORMAL...ESPECIALLY ACROSS
THE PIEDMONT. HOWEVER...WITH LIGHT SOUTHEASTERLY FLOW...WE STILL
EXPECT UNIFORM TEMPERATURES IN THE LOW TO MID 80S ACROSS THE
AREA...UPPER 70S ALONG HIGHER RIDGES.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 330 PM EDT FRIDAY...
A GENERAL SUMMERTIME WEATHER PATTERN WILL RETURN FOR THE MIDDLE OF
NEXT WEEK...WITH SPOTTY SHOWERS AND THUNDERSTORMS DEVELOPING EARLY
EACH AFTERNOON WITH DAYTIME HEATING...AND DIMINISHING TOWARD SUNSET
AS HEATING ENDS. EXPECT ONLY SPOTTY COVERAGE OF RAINFALL ON TUESDAY
DUE TO WEAK SUPPORTING DYNAMICS...HOWEVER COVERAGE WILL INCREASE
EACH DAY FOR WEDNESDAY AND THURSDAY AS A COLD FRONT APPROACHES FROM
THE NORTHWEST.
BY NEXT THURSDAY...LONG RANGE WEATHER FORECAST MODELS DIFFER AS TO
WHERE THE COLD FRONT WILL BE LOCATED...WITH THE ECMWF MODEL BRINGING
THE FRONT ACROSS OUR AREA...WHILE THE GFS MODEL KEEPS THE FRONT WELL
TO OUR NORTH. GIVEN WHAT APPEARS TO BE WEAK UPPER LEVEL SUPPORT TO
GIVE THE FRONT A SOUTHWARD PUSH...HAVE TRENDED TOWARD THE GFS MODEL
AND TRIMMED BACK RAIN CHANCES FOR THAT DAY.
EXPECT WARM AND MUGGY CONDITIONS FOR THE PERIOD...WITH HIGHS RANGING
FROM THE UPPER 70S/LOW 80S ACROSS THE MOUNTAINS...TO THE UPPER 80S
FOR THE PIEDMONT. LOWS WILL HOLD GENERALLY IN THE LOW TO MID
60S...PERHAPS WITH A FEW UPPER 50S ACROSS THE MOUNTAINS.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 740 AM EDT SATURDAY...
TRUE BACKDOOR COLD FRONT LOCATED NEAR AN MRB-LYH-RDU LINE...WITH
MARITIME AIR NOW SURGING INTO THE EASTERN PART OF THE STATE. THIS
UPSLOPE MARITIME EASTERLY FLOW IS QUICKLY BEING REALIZED IN MVFR
CIGS AND MVFR VSBYS IN LOW CLOUDS AND FOG. ALSO...AS WELL DEPICTED
BY THE HRRR...PATCHES OF -SHRA/-DZ ALSO BEGINNING TO DEVELOP ALONG
THE LEADING EDGE OF THIS BOUNDARY...AND THIS ACTIVITY WILL
TRANSLATE WEST TOWARD THE ALLEGHANYS WITH THE BACKDOOR FRONT
THROUGH EARLY AFTERNOON. EXPECT WIDESPREAD MVFR...SOME IFR CIGS
ROA/LYH/DAN THROUGH 15Z...THROUGHOUT THE DAY. ANY IMPROVEMENT
DURING LATE AFTERNOON/EARLY EVENING...WILL QUICKLY DETERIORATEAGAIN
AFT 00Z. VSBYS ARE NOT EXPECTED TO GO BELOW MVFR CONDITIONS IN
THESE AREAS. PRECIPITATION EAST OF THE BLUE RIDGE WILL BE LIMITED
MOSTLY TO THIS MORNING.
TO THE WEST...LOW CLOUDS WERE ALSO ADVECTING/DEVELOPING INTO THE
REGION...BUT WILL LIKELY NOT PERSIST ALL DAY WEST OF THE BLUE
RIDGE. HOWEVER...NEAR THE ALLEGHANY FRONT AND I-77
CORRIDOR...GREATER POTENTIAL FOR SHOWERS/THUNDERSTORMS DURING THE
AFTERNOON...SO HAVE CONTINUED TO INCLUDE A VCTS AT BLF...BUT FEEL
THAT LWB/BCB WILL ESCAPE THIS. BETTER CHANCE FOR CONVECTION WILL
BE NEAR THE VA/NC/TN BORDER. CIGS MOSTLY MVFR IN THESE
AREAS...WITH SOME PERIOD OF VFR CIGS POSSIBLE DURING THE LATE
AFTERNOON/EARLY EVENING. THESE AREAS WILL SEE MVFR-IFR CIGS BY SUN
MORNING...HOWEVER WITH MVFR BR. EXCEPTION IS LWB...WHICH HAD
ENOUGH CLEARING FRI EVENING TO ALLOW LIFR FG TO DEVELOP AGAIN THIS
MORNING. THIS COULD PERSIST UNTIL AROUND 15
WINDS NE 6-9KTS WITH LOW END GUSTS...ESPECIALLY EAST OF THE BLUE
RIDGE LATE MORNING INTO MID-AFTERNOON.
MEDIUM CONFIDENCE IN CIGS THROUGH THE TAF VALID PERIOD.
MEDIUM CONFIDENCE IN VSBYS THROUGH THE TAF VALID PERIOD.
MEDIUM TO HIGH CONFIDENCE IN WIND SPD/DIR THROUGH THE TAF VALID
PERIOD.
MEDIUM CONFIDENCE IN TSRA POTENTIAL WEST THIS AFTERNOON.
EXTENDED AVIATION DISCUSSION...
HIGH PRESSURE WILL GRADUALLY WORK INTO THE REGION BY THE END OF
THE WEEKEND...AND REMAIN OVER THE AREA INTO THE EARLY PART OF
NEXT WEEK. LINGERING MOISTURE AND AN EASTERLY FETCH WILL HELP
MAINTAIN SOME ISOLATED TO SCATTERED SHOWERS ACROSS MAINLY WESTERN
PARTS OF THE AREA. THIS MOISTURE WILL BEGIN TO RETURN NORTH AND
EAST BY MONDAY WITH CHANCES FOR SHOWERS AND THUNDERSTORMS
INCREASING THROUGH MID-WEEK AS INSTABILITY INCREASES AND A COLD
FRONT APPROACHES FROM THE WEST.
PAST SATURDAY...CEILINGS AND VISIBILITIES WILL PRIMARILY BE
VFR OUTSIDE EARLY MORNING PATCHY DENSE FOG AND AFTERNOON
SHOWERS/THUNDERSTORMS.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...RAB
NEAR TERM...RAB
SHORT TERM...RCS
LONG TERM...NF
AVIATION...DS/RAB/WP
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
951 AM MDT SAT SEP 5 2015
.UPDATE...
ISSUED AT 951 AM MDT SAT SEP 5 2015
A FEW LIGHT SHOWERS AND SPRINKLES MOVING ACROSS NORTHERN PORTIONS
OF THE NEBRASKA PANHANDLE AT THIS TIME. THIS AREA OF SHOWERS WILL
QUICKLY MOVE OUT OF THE AREA BEFORE MORNINGS END BUT MORE SHOWER
ACTIVITY TO DEVELOP ACROSS THE FORECAST AREA THIS AFTERNOON.
UPDATED POP AND SKY COVER FORECAST TO REFLECT CURRENT CONDITIONS
AND TWEAKED CHANCES FOR SHOWERS AND THUNDERSTORMS THIS AFTERNOON.
BASED ON THE HRRR MODEL PERFORMANCE THE LAST FEW DAYS...ADDED
ISOLATED SHOWERS AND THUNDERSTORMS TO THE ENTIRE WESTERN NEBRAKSA
PANHANDLE THIS AFTERNOON.
ONCE AGAIN VERY LITTLE IN THE WAY OF MEASURABLE PRECIPITATION IS
EXPECTED. MAINLY LOOKING FOR A TRACE TO A FEW HUNDRETHS OF AN INCH
OF PRECIPITATION WITH LOCALLY HIGHER AMOUNTS WITH ANY THUNDERSTORM
ACTIVITY. THUNDERSTORMS WILL BE FEW AND FAR BETWEEN. INVERTED V
SOUNDINGS WILL ONCE AGAIN SUGGESTIVE OF GUSTY DOWNDRAFT/OUTFLOW
WINDS WITH SOME SHOWERS AND THUNDERSTORMS TODAY. GUSTS OF 40 TO 50
MPH LIKELY WITH SOME SHOWERS AND THUNDERSTORMS.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 303 AM MDT SAT SEP 5 2015
PREDAWN WATER VAPOR IMAGERY DEPICTED A UPPER TROUGH OVER THE
NORTHWEST CONUS WITH A LOW CENTERED OVER OR. A LARGE UPPER RIDGE
ENCOMPASSED THE EASTERN 2/3 OF THE NATION. SUBTROPICAL/MONSOON
MOISTURE CONTINUED TO STREAM NORTHEAST FROM BAJA CA INTO THE
ROCKIES AND HIGH PLAINS. A PASSING WEAK SHORT WAVE OVER FAR
SOUTHEAST WY AND WESTERN NE PRODUCED SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS. THIS ACTIVITY WILL END BY DAYBREAK. SKIES
WERE MOSTLY CLOUDY WITH LIGHT WINDS AND TEMPERATURES IN THE 50S
AND 60S.
THE SHORT RANGE MODELS HAVE MAINTAINED THEIR RUN-TO-RUN CONSISTENCY
FOR SEVERAL DAYS PROGGING THE PACIFIC NORTHWEST UPPER LOW TO LIFT
NORTHEAST THROUGH ID AND MT DURING THE NEXT 24 HOURS. THE MOIST
SOUTHWEST FLOW ALOFT WILL PROVIDE CHANCES FOR SHOWERS AND ISOLATED
THUNDERSTORMS FROM LATE THIS MORNING THROUGH THE AFTERNOON AND
EVENING...ESPECIALLY WEST OF I-25. GUSTY WINDS UP TO 45 MPH...
LIGHTNING AND BRIEF MODERATE TO HEAVY RAIN WILL BE THE PRIMARY
HAZARDS. OUTSIDE OF THE CONVECTION...SOUTHWEST WINDS WILL GUST TO
35 MPH WEST OF THE LARAMIE RANGE. IT WILL BE ANOTHER WARM AFTERNOON
FOR THE PLAINS WITH HIGHS IN THE 80S TO AROUND 90.
A PACIFIC COLD FRONT IS FORECAST TO MOVE EAST ACROSS THE CWA LATE
TONIGHT AND EARLY SUNDAY MORNING...USHERING IN A DRIER AND MORE
STABLE AIR MASS. WEST TO NORTHWEST WINDS WILL INCREASE TO 25 TO
35 MPH BEHIND THE FRONT SUNDAY MORNING...WITH HIGHER GUSTS
POSSIBLE IN WIND PRONE AREAS OF SOUTHEAST WY. SUNDAY WILL BE 5 TO
10 DEGREES COOLER WITH HIGHS IN THE 70S TO LOWER 80S.
MONDAY WILL BE A PLEASANT DAY WITH NEAR SEASONABLE TEMPERATURES. A
WEAK SURFACE TROUGH IS PROGGED BY MOST OF THE MODELS TO SET UP NEAR
THE WY-NE BORDER MONDAY WITH A FEW SHOWERS OR THUNDERSTORMS POSSIBLE
OVER THE FAR SOUTHEAST PART OF THE CWA...ROUGHLY EAST OF A ALLIANCE
TO SIDNEY LINE. BREEZY WEST WINDS WILL DEVELOP ALONG AND WEST OF
THE LARAMIE RANGE MONDAY AFTERNOON.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 300 AM MDT SAT SEP 5 2015
A LOW AMPLITUDE CYCLONIC UPPER FLOW SHOULD EXIST OVER SRN CANADA
AND THE NORTHERN TIER STATES MOST OF NEXT WEEK. SEVERAL UPPER
SHORT WAVES WILL TRANSLATE EAST ACROSS THE REGION IN THIS FLOW
PATTERN BRINGING SURGES OF COOLER AIR. ONE MINOR FRONT WILL SCOOT
ACROSS MONDAY NIGHT BUT HAVE LITTLE EFFECT ON THE SENSIBLE WEATHER
ACROSS THE CWA WITH WARM AND DRY WEATHER EXPECTED FOR TUESDAY AND
WEDS. A LITTLE STRONGER FRONT LOOKS TO PASS ACROSS LATER WEDS BUT
AGAIN LOOKS DRY. MILD TEMPS THURSDAY THEN A STRONGER SHORTWAVE
WILL MOVE SOUTHEAST OUT OF SOUTHERN CANADA INTO THE PLAINS THURSDAY
NIGHT DRIVING YET ANOTHER PUSH OF COOLER AIR SOUTH OUT OF CANADA
AND REINFORCING THE MILD AIR MASS OVER THE REGION. THIS SYSTEM MAY
BRING A FEW SHOWERS TO MAINLY THE PANHANDLE FRIDAY IN ASSOCIATION
WITH THE PASSING OF THE SHORT WAVE...THOUGH BETTER ENERGY SHOULD
PASS TO THE EAST OF THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 300 AM MDT SAT SEP 5 2015
VFR EXPECTED OVER ALL TERMINALS THROUGH THE PERIOD. ISOLATED
SHOWERS AND TSTMS SHOULD DEVELOP OVER PARTS OF THE AREA THIS
AFTERNOON THEN DISSIPATE THIS EVENING. SURFACE COLD FRONT WILL
PASS ACROSS THE AREA LATER TONIGHT.
&&
.FIRE WEATHER...
ISSUED AT 300 AM MDT SAT SEP 5 2015
MOIST SOUTHWEST FLOW ALOFT WILL PRODUCE SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS TO MOST OF THE FORECAST AREA THIS AFTERNOON
AND EVENING. THERE IS A LOW RISK OF DRY LIGHTNING. CRITICAL FIRE
WEATHER CONDITIONS WILL DEVELOP SUNDAY FOLLOWING THE PASSAGE OF A
COLD FRONT. WESTERLY WINDS WITH FREQUENT GUSTS OF 30 TO 40 MPH ARE
EXPECTED. DESPITE THE COOLER TEMPERATURES...RELATIVE HUMIDITIES
WILL FALL TO 10 TO 15 PERCENT SUNDAY AFTERNOON OVER PORTIONS OF
EAST AND SOUTH CENTRAL WYOMING.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...FIRE WEATHER WATCH FROM SUNDAY MORNING THROUGH SUNDAY EVENING
FOR WYZ301>303-308.
NE...NONE.
&&
$$
UPDATE...SML
SHORT TERM...MAJ
LONG TERM...RE
AVIATION...RE
FIRE WEATHER...MAJ
AREA FORECAST DISCUSSION
NWS TUCSON AZ
955 AM MST SAT SEP 5 2015
.SYNOPSIS...EXPECT SCATTERED SHOWERS THROUGH TONIGHT. HOWEVER...ANY
THUNDERSTORMS WILL BE QUITE LIMITED INTO TONIGHT. SCATTERED SHOWERS
AND THUNDERSTORMS WILL THEN OCCUR SUNDAY THROUGH TUESDAY. A SLIGHT
CHANCE OF THUNDERSTORMS WILL PREVAIL WEDNESDAY THROUGH FRIDAY...
ESPECIALLY EAST OF TUCSON. BELOW NORMAL TEMPERATURES WILL OCCUR
TODAY FOLLOWED BY A WARMING TREND STARTING SUNDAY AND
CONTINUING DURING THE UPCOMING WEEK.
&&
.DISCUSSION...SCATTERED TO NUMEROUS SHOWERS PRODUCING MOSTLY LIGHT
RAINFALL WAS OCCURRING ACROSS PORTIONS OF SE ARIZONA AT THIS TIME.
THE BULK OF THESE SHOWERS WAS ACROSS SE PINAL COUNTY...CENTRAL/ERN
PIMA COUNTY SWD INTO SANTA CRUZ COUNTY. MOST RAINFALL AMOUNTS SINCE
7 AM MST HAVE BEEN LESS THAN ONE TENTH OF AN INCH. HOWEVER...A FEW
GAUGES IN THE MOUNTAINS HAVE RECORDED UP TO ONE QUARTER ON AN INCH.
OTHERWISE...IR/VISIBLE SATELLITE IMAGERY DEPICTED CLOUDY SKIES
ACROSS MUCH OF SE ARIZONA. HOWEVER...MOSTLY SUNNY SKIES PREVAILED
ACROSS FAR WRN PIMA COUNTY. AMPLE MOISTURE WAS IN PLACE ACROSS THIS
FORECAST AREA...WITH 05/12Z KTWC SOUNDING TOTAL PRECIP WATER VALUE
OF 1.64 INCHES. THE SOUNDING DEPICTED A MARGINALLY UNSTABLE
ENVIRONMENT...WITH LIFTED INDEX VALUES RANGING FROM MINUS 1 TO MINUS
3 DEPENDING UPON THE LIFTING METHOD. 05/12Z UPPER AIR PLOTS DEPICTED
UPPER TROUGH OVER THE PACIFIC NW WITH HIGH PRESSURE ALOFT CENTERED
OVER WEST CENTRAL TEXAS. LIGHT TO MODERATE SWLY FLOW ALOFT PREVAILED
ACROSS SE ARIZONA.
BASED ON RADAR/SATELLITE TRENDS AND SEVERAL HRRR SOLUTIONS...APPEARS
THAT THE ONGOING AREA OF SHOWERS WILL GRADUALLY SHIFT EASTWARD
DURING THE NEXT SEVERAL HOURS. HAVE NOTED THAT THE 05/12Z UNIV OF AZ
WRF-NAM DEPICTS SOME STRONGER PRECIP ECHOES SUGGESTING THE POTENTIAL
FOR THUNDERSTORMS MAY OCCUR THIS AFTERNOON ACROSS WRN SECTIONS...AND
ACROSS WRN/CENTRAL COCHISE COUNTY. BELIEVE THAT THERE WILL NEED TO
BE AT LEAST SOME CLEARING FOR ANY THUNDERSTORMS TO EVENTUALLY OCCUR.
THERE ARE SOME INDICATIONS AS PER VISIBLE SATELLITE IMAGERY
SUGGESTING BRIEF CLEARING MAY OCCUR DURING THE NEXT 1-2 HOURS SE OF
TUCSON.
AT ANY RATE...WILL MAINTAIN SCATTERED SHOWERS AND A SLIGHT CHANCE OF
THUNDERSTORMS INTO THIS EVENING. WILL LIKELY MAKE SOME MINOR
DOWNWARD ADJUSTMENTS TO HIGH TEMPS FOR TODAY...ESPECIALLY FOR
LOCALES WHERE SHOWERS ARE ONGOING.
PLEASE REFER TO THE ADDITIONAL SECTIONS FOR FURTHER DETAIL.
&&
.AVIATION...VALID THRU 06/18Z.
SCATTERED TO NUMEROUS -SHRA WILL OCCUR INTO THIS EVENING. THERE WILL
ALSO BE A SLIGHT CHANCE OF -TSRA...PARTICULARLY THIS AFTERNOON AND
EVENING. ISOLATED TO SCATTERED -SHRA AND A SLIGHT CHANCE OF -TSRA
WILL THEN OCCUR LATE TONIGHT INTO SUNDAY MORNING. OTHERWISE...
BROKEN TO OVERCAST CLOUDS RANGING FROM 8-12K FT AGL AND SURFACE WIND
MAINLY LESS THAN 10 KTS WILL PREVAIL INTO SUNDAY MORNING. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...SCATTERED SHOWERS AND A SLIGHT CHANCE OF
THUNDERSTORMS WILL OCCUR INTO TONIGHT. SCATTERED SHOWERS AND
THUNDERSTORMS WILL THEN PREVAIL SUNDAY THROUGH TUESDAY. ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS ARE FORECAST TO OCCUR WEDNESDAY
THROUGH FRIDAY. THE BULK OF THESE SHOWERS AND THUNDERSTORMS DURING
THE LATTER PART OF THE WEEK SHOULD BE EAST OF TUCSON.
&&
.PREVIOUS DISCUSSION /325 AM MST/...MOISTURE REMAINING IN PLACE ON
SUNDAY FOR A CHANCE OF SHOWERS AND THUNDERSTORMS WITH HIGHS SLIGHTLY
WARMER THAN TODAY.
MONDAY AND TUESDAY...ANOTHER TROPICAL SYSTEM IS FORECAST TO PASS
WEST OF SRN BAJA. FOR OUT NECK OF THE CACTI...FLOW ALOFT WILL BECOME
MORE WESTERLY...ESPECIALLY ON TUESDAY. STILL ENOUGH MOISTURE AROUND
FOR A SLIGHT CHANCE OF STORMS BOTH DAYS.
WEDNESDAY AND THURSDAY...THE TRACK OF ABOVE MENTIONED TROPICAL
SYSTEM WILL BE THE DRIVING FACTOR FOR THESE TWO DAYS. EC/CANADIAN
HAS TRACK CLOSER/FURTHER N OFF BAJA COAST VERSUS GFS. FOR NOW WILL
MAINTAIN LOW GRADE MONSOON FORECAST.
HIGHS WILL GRADUALLY WARM TO NEAR NORMAL LEVEL BY EARLY NEXT WEEK.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
FRANCIS
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
238 PM MDT SAT SEP 5 2015
.SHORT TERM...(TONIGHT THROUGH SUNDAY NIGHT)
ISSUED AT 234 PM MDT SAT SEP 5 2015
AVAILABLE MOISTURE REMAINS ABOVE NORMAL AND IS LENDING ITSELF TO
SOME CONVECTION THAT HAS ALREADY FORMED THIS EARLY AFTERNOON.
STORMS ARE MOVING AT A GOOD CLIP SO BIGGEST CONCERN FROM STORMS
WILL BE GUSTY WINDS OF 30 TO 40 MPH WITH SOME HEAVY SHOWERS UNDER
THE STRONGER CELLS. HRRR INITIALIZED VERY WELL...MUCH BETTER THAN
NAM12/GFS...AND IT HIGHLIGHTS CURRENT CONVECTION AND MORE ISOLD
STORMS/SHOWERS AS THE AFTERNOON WEARS ON AS OPPOSED TO MORE
WIDESPREAD PRECIP. WOULDN`T BE SURPRISED TO SEE SOME STRONGER
STORMS ALONG THE PERIPHERY OF THE CLOUD SHIELD DOWN SOUTH DUE TO
DIFFERENTIAL HEATING. EITHER WAY...ONE LAST DAY OF SHOWERS AND
THUNDERSTORMS BEFORE DRYING REALLY KICKS IN. MOST CONVECTION WILL
DIE DOWN SHORTLY AFTER SUNSET THOUGH A FEW ISOLATED SHOWERS/STORMS
POSSIBLE OVERNIGHT.
SUNDAY THE STALLED FRONT STRETCHED ACROSS THE CENTRAL FORECAST
AREA QUICKLY ERODES. ITS DRIER AIR MASS DOES LIMIT AVAILABLE
MOISTURE. BETTER MOISTURE REMAINS OVER THE SOUTHERN AND CENTRAL
ZONES FOR ANOTHER ROUND OF SCATTERED LATE DAY SHOWERS AND STORMS.
TEMPERATURES WILL SHOW LITTLE CHANGE.
SUNDAY NIGHT THE NEXT TROUGH WORKS THROUGH THE NORTHERN ROCKIES
FOR SOME FORCING NEAR THE WYOMING BORDER. SHOWERS MAY PERSIST INTO
MONDAY MORNING OVER NW COLORADO.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 234 PM MDT SAT SEP 5 2015
PROGRESSIVE WESTERLIES ACROSS THE NORTHERN TIER OF STATES PROVIDE
A DRIER W-NW FLOW THROUGH THE NEW WORK WEEK. THIS PROVIDES A DRY
WEEK IN THE MIDST OF WHAT IS NORMALLY OUR WETTEST TIME OF YEAR.
MONDAY THROUGH TUESDAY...OPEN TROUGHS CONTINUE TO SWEEP THROUGH
THE NORTHERN ROCKIES. WEAK FORCING ACROSS THE NORTH IS LIMITED BY
A DRY AIR MASS THERE. ISOLATED TO SCATTERED LATE-DAY STORMS WILL
FAVOR THE CENTRAL-SOUTHERN COLORADO MOUNTAINS. AFTERNOONS WILL BE
BREEZY TO WINDY AT TIMES.
WEDNESDAY THROUGH THURSDAY...DISTURBANCES CONTINUE TO DIVE THROUGH
THE NORTHERN ROCKIES BUT WITH THE SUB-TROPICAL RIDGE AMPLIFYING
ALONG THE WEST COAST SHIFTS THE FLOW TO DRIER NW. STORM COVERAGE
WILL BE ISOLATED AT BEST. AFTERNOON TEMPERATURES CLIMB WELL ABOVE
NORMAL FOR LATE SUMMER.
FRIDAY THROUGH SATURDAY...THE RIDGE AMPLIFIES ALONG THE WEST
COAST. THE EC HAS THE RIDGE INLAND WHILE THE PREFERRED GFS KEEPS
THE RIDGE CENTER OFFSHORE. EITHER SOLUTION SHIELDS THE REGION FROM
HURRICANE IGNACIO AND KEEPS THE DRY PATTERN IN PLACE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 235 PM MDT SAT SEP 5 2015
LATE DAY STORMS ARE FAST MOVING...TO THE NE AT 20-25KTS. FOR MTN
TAF SITES AND KMTJ...CIG/VIS MAY DROP BRIEFLY BELOW ILS BREAK
POINTS. CONVECTION WILL DIE DOWN BY 03Z WITH ONLY ISOLATED
SHOWERS/STORMS CONTINUING OVERNIGHT. AFT 18Z SUNDAY STORMS WILL BE
ISOLATED IN COVERAGE MAINLY SOUTH OF THE I-70 CORRIDOR.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...TGR/JOE
LONG TERM...JOE
AVIATION...JOE
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
353 PM EDT SAT SEP 5 2015
.REST OF THE AFTERNOON...SCT TO NUMEROUS SHOWERS AND STORMS
FORMED QUICKLY TODAY OVER NE FL AND PROPAGATED WWD TO INLAND
AREAS. COVERAGE ENDING UP A BIT HIGHER SO HAVE ADJUSTED POPS TO
60-70 PERCENT OVER INLAND NE FL. MAIN CONCERNS WILL BE GUSTY
WINDS...LIGHTNING AND HEAVY DOWNPOURS. FOR SE GA AND REST OF
COASTAL NE FL ONLY 20-40 PERCENT RAIN CHANCES EXPECTED PER RADAR
TRENDS AND HRRR MODEL RUNS. PREVAILING FLOW ON LATEST ANALYSIS IS
NE TO E WITH THE FOCUS OF CONVERGENCE OVER THE SUWANNEE VALLEY
AREA.
.SHORT TERM /TONIGHT THROUGH TUESDAY/...
TONIGHT...AS MENTIONED...FOCUS OF CONVECTION WILL BE OVER
INTERIOR NERN FL WITH ACTIVITY WINDING DOWN FAIRLY QUICKLY THROUGH
THE EVENING HOURS. WARM OCEAN WATERS AND CONVERGENCE IN N TO NE
10-15KT FLOW SHOULD ALLOW FOR OCNL ISOLD TO SCT SHOWERS AND
PERHAPS A THUNDERSTORM FOR THE ATLC MARINE WATERS. SOME SHOWER
ACTIVITY OFF THE ATLC WATERS WILL BE POSSIBLE FOR THE COASTAL
COUNTIES OVERNIGHT WITH 0-5KFT LEVEL FLOW JUST STRONG ENOUGH AT
10-15 KT. SFC HIGH PRES RIDGE WILL REMAIN ACROSS THE MID ATLC AREA
AT 1024 MB.
SUNDAY...WEAK INVERTED TROUGH BEGINS THE DAY ALONG THE COASTAL
WATERS WITH HIGH PRES RIDGE NOSING DOWN THROUGH NRN GA AND AL.
GFS AND NAM SUGGESTS SOMEWHAT LOWER MOISTURE TO WORK WITH FOR
CONVECTIVE CHANCES. THINK HIGH END SCATTERED RANGE AROUND 40-50
PERCENT IS REASONABLE AT THIS TIME. SHOWERS AND STORMS WILL BEGIN
OVER THE ERN ZONES FIRST HALF OF THE DAY...LIKE TODAY...THEN
PROPAGATE INLAND. WITH A SLIGHTLY STRONGER CAP...INSTABILITY
RELEASED IN THE AFTN COULD RESULT IN ISOLD STRONG STORMS GIVEN A
BIT STEEPER LAPSE RATES WITH THE MID AND UPPER LEVEL LOW MOVING
ACROSS THE REGION. TEMPS EXPECTED FROM MID 80S TO NEAR 90...LOWER
THAN PRIOR DAYS WITH 850 MB TEMPS AT LEAST 1 DEG LOWER. NE-E
WINDS STAY BELOW BREEZY LEVELS.
SUNDAY NIGHT THROUGH TUESDAY...
THIS PERIOD WILL BE MARKED BY A CONTINUATION OF WARM AND HUMID
CONDITIONS WITH SCATTERED TO NUMEROUS SHOWERS AND STORMS EACH DAY.
THE CLOSED UPPER LOW OVER THE REGION WILL CONTINUE TO RETROGRADE
WEST SOUTHWEST SUNDAY NIGHT INTO EARLY NEXT WEEK. UPPER RIDGING TO
OUR SOUTHEAST WILL TAKE BACK OVER BY MID WEEK AS THE UPPER LOW
RETROGRADES ALL THE WAY TO THE WESTERN GULF OF MEXICO. AT THE
SURFACE...AN INVERTED TROUGH NEAR THE COAST WILL REMAIN
INFLUENTIAL EARLY IN THE WEEK. DEEP MOISTURE WILL REMAIN IN PLACE
AND OUR DIURNAL STORM CHANCES WILL REMAIN HIGHER THAN NORMAL FOR
THIS TIME OF YEAR. ONSHORE FLOW WILL INITIALLY FAVOR AN EAST TO
WEST PROGRESSION OF SHOWERS/STORMS WITH ACTIVITY GETTING STARTED
NEAR THE ATLANTIC COAST DURING THE MORNING HOURS. BY
TUESDAY...FLOW WILL BECOME LIGHT ENOUGH TO SUPPORT AN EARLY START
TO BOTH SEABREEZES WITH CONVECTION MOVING IN FROM BOTH COASTS
DURING THE MORNING HOURS.
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
INVERTED TROUGH BREAKS DOWN AND SURFACE RIDGING WILL SHIFT TO OUR
SOUTH AS A FRONT STALLS TO OUR NORTH. THIS WILL SHIFT THE PATTERN
TO A SOUTHWESTERLY FLOW WITH AT LEAST SCATTERED SHOWERS/STORMS
PROGRESSING WEST TO EAST EACH DAY WITH ACTIVITY GETTING OFF TO A
MORNING START ACROSS OUR WESTERN ZONES. BROAD UPPER TROUGHING WILL
BRING A DECREASE IN HEIGHTS BY LATE IN THE WEEK...BUT THE OVERALL
FORECAST DOES NOT CHANGE ALL THAT MUCH...PERHAPS A LITTLE LOWER
ON DAYTIME TEMPS...BUT RAIN CHANCES WILL REMAIN ABOVE NORMAL
LEVELS.
&&
.AVIATION...SHOWERS AND STORMS AFFECTING LOCATIONS AROUND GNV AND
SGJ WITH MOST OTHER ACTIVITY IN THE VICINITY. ANTICIPATE
PREVAILING VFR LATER THIS AFTERNOON AND OVERNIGHT. MVFR VSBY IN
BR POSSIBLE AT GNV AND VQQ AFTER 06Z-13Z. SHOWERS AND A FEW
STORMS POSSIBLE BY MID TO LATE SUN MORNING BUT CHANCES REMAIN LOW
WITH VCSH FOR NOW BY 15Z.
&&
.MARINE...NE TO E FLOW EXPECTED THROUGH SUNDAY AS HIGH PRES
WEDGES SOUTH TO ACROSS THE APPALACHIANS. WINDS AND SEAS STILL
EXPECTED TO REMAIN BELOW HEADLINE CRITERIA. WINDS DECREASE
BEGINNING EARLY NEXT WEEK AS THE WEDGE AND INVERTED TROUGH WEAKEN.
RIP CURRENTS: A LOW RISK CONTINUES TODAY WITH A MODERATE RISK
POSSIBLE FOR SUNDAY AS AN ONSHORE FLOW INCREASES.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 71 89 70 89 / 30 40 10 50
SSI 75 85 74 85 / 20 50 30 40
JAX 73 87 71 88 / 20 40 20 50
SGJ 75 86 74 85 / 20 50 20 50
GNV 70 89 71 88 / 20 40 30 60
OCF 71 89 71 88 / 20 50 30 60
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...NONE.
&&
$$
SHASHY/SHULER/
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1222 PM CDT SAT SEP 5 2015
...Update to aviation forecast discussion...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 231 AM CDT SAT SEP 5 2015
Not much change to the overall pattern with southwest flow aloft
over the central and southern plains keeping the lee side trough in
place and a decent pressure gradient across eastern KS. Temperatures
will be a few degrees higher today so expect highs in the low to mid
90s with a few locations possibly reaching the upper 90s in central
KS. Southerly winds will again increase later today around 15 to 25
mph with gusts up to 35 mph. Later this morning a weak shortwave
will track over western NE and support showers and storms possibly
as far east as north central KS. The latest runs of the HRRR are now
hinting at isolated development in that area around sunrise, but
decided not to increase pops given the low uncertainty. The models
are showing mid level moisture spreading northward from the gulf
today coupled with cooler 850 mb temperatures across southeast KS.
This may lead to a weaker cap and an isolated shower or storm could
be possible south of I-35 this afternoon as daytime heating erodes
this cap. There is no obvious mid level support or any other focus
for lift so did not increase pops, but it could not be completely
ruled out. Tonight a cold front will drift eastward through the high
plains while several weak mid-level shortwaves track over the same
area. This should support storm development along the front in NE
during the overnight hours although have kept the northern forecast
area dry through sunrise.
.LONG TERM...(Sunday THROUGH Friday)
ISSUED AT 231 AM CDT SAT SEP 5 2015
Front still advancing across the Northern Plains on Sunday and
just starts to move into the far northwestern CWA by the late
afternoon hours. This leaves much of the area parked under the
thermal ridge for Sunday, with temperatures rising well into the
middle 90s. Heat indicies look to range from near 100 to 102F by
the afternoon hours. Northern counties may get some relief
overnight as front moves southward about halfway across the CWA,
but stalls out without a strong push to get the front south of the
area. As storms move into the area, some of the storms could be
strong with good instability available and dry air in the low
levels, but wind shear is not strong nor are the lapse rates
aloft. Front may actually retreat back toward the north on Monday
as next upper shortwave trot moves into the northern plains,
before getting a push southward in the overnight hours Monday
night into early Tuesday. Have highs Monday near 90 in the south
to middle 80s north and will need to watch progression of the
front for sensible weather effects.
Synoptic pattern over the Central Plains remains zonal in nature,
with surface front near the area for much of the remainder of the
week with shortwave profs passing through the flow overhead.
Temperatures slowly fall Tuesday through Friday with rain chances
for much of the period given close proximity of the front. Upper
trot looks to deepen across the Great Lakes late in the week, and
usher in cooler high pressure behind.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z Sunday AFTERNOON)
ISSUED AT 1222 PM CDT SAT SEP 5 2015
VFR conditions will persist. Minor occasional gusts are likely in
the 16-23Z periods. LLWS may develop after 03Z but at this point
looks too uncertain to include.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Sanders
LONG TERM...67
AVIATION...65
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
158 PM EDT SAT SEP 5 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 308 AM EDT SAT SEP 5 2015
A WARM FRONT WILL LIFT NORTHWARD THROUGH THE REGION TODAY LEADING
TO SOME SHOWERS AND THUNDERSTORMS. HIGH PRESSURE CONTROLS OUR
WEATHER ON SUNDAY WHICH SHOULD END UP A MOSTLY DRY AND VERY WARM
DAY. THE CHANCES FOR SHOWERS AND THUNDERSTORMS WILL INCREASE AS WE
GO THROUGH LABOR DAY AND INTO TUESDAY AS A SLOW MOVING COLD FRONT
NEARS FROM THE WEST. THE TEMPERATURES WILL STILL END UP WELL ABOVE
NORMAL EARLY NEXT WEEK.
&&
.UPDATE...
ISSUED AT 1039 AM EDT SAT SEP 5 2015
WE HAVE UPDATED TO FCST THIS MORNING TO EXTEND THE DENSE FOG
ADVISORY UNTIL NOON UP NORTH. WE HAVE ALSO INCREASED THE
SHOWER/STORM CHCS DOWN SOUTH WITH PLENTY OF COVERAGE ALREADY IN
PLACE DOWN THERE.
THE FOG UP NORTH HAS BEEN SLOW TO DISSIPATE THIS MORNING WITH MANY
LOCATIONS STILL AT 1/4SM OR LESS LEADING UP TO THE INITIAL
EXPIRATION TIME OF 10 AM THIS MORNING. WITH A LACK OF WIND TO MIX
THINGS UP AND PLENTY OF STRATUS IN PLACE...IT WILL TAKE A LITTLE
LONGER THAN PREVIOUSLY EXPECTED TO MIX IT OUT. WE GAVE IT UNTIL
NOON FOR MORE OF A BUFFER. WE WILL CANCEL IT EARLY IF ALL SITES
COME UP SOONER.
PLENTY OF SHOWERS AND STORMS ACROSS THE SOUTH THIS MORNING. THE
PESKY WEAK UPPER LOW THAT HAS BEEN MEANDERING ACROSS THE STATE THE
PAST COUPLE OF DAYS IS OVER LAKE MICHIGAN EARLY THIS MORNING. IT
NOW LOOKS LIKE IT IS MAKING A MOVE TO THE EAST...AND FIRING PLENTY
OF SHOWERS/STORMS AHEAD OF IT WITH THE MOIST AIR MASS IN PLACE.
IT APPEARS THIS WILL CONTINUE EAST THROUGH THE DAY AND PUSH THE
MORE WIDESPREAD COVERAGE EAST BY LATER THIS AFTERNOON. WE CAN NOT
RULE OUT A POP UP SHOWER/STORM WITH THE UPPER LOW STILL NEARBY.
WEAK SHEAR AND LIMITED INSTABILITY WILL KEEP THINGS GENERALLY
TAME. HEAVY DOWNPOURS WOULD BE THE GREATEST THREAT WITH THE SLOW
MOVEMENT.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 308 AM EDT SAT SEP 5 2015
DENSE FOG HAS BEEN INCREASING OVER THE PAST FEW HOURS AND NOW
COVERS MUCH OF THE REGION. HRRR RUC SUGGESTS THE FOG WILL PERSIST
THROUGH DAYBREAK. WILL GO WITH AN ADVISORY AND CARRY IT UNTIL MID
MORNING. WE MAY SEE GRADUAL IMPROVEMENT IN THE VISIBILITIES FROM
SOUTH TO NORTH BEFORE DAYBREAK AS THE ELEVATED WARM FRONT MOVES
IN.
THE ATMOSPHERE WILL BE UNSTABLE THROUGH THE DAY. SOME LIFT ARRIVES
WITH THE ELEVATED WARM FRONT MOVING IN THIS MORNING FROM THE
SOUTH. THEREFORE WILL KEEP THE MENTION OF SHOWERS AND
THUNDERSTORMS IN THE FORECAST. LITTLE OR NO FORCING IS AROUND
TONIGHT INTO SUNDAY. WILL KEEP IT DRY FOR NOW. THE ATMOSPHERE
BECOMES RATHER UNSTABLE ON SUNDAY...SO WILL NEED TO MONITOR THIS
CLOSELY. SUNDAY SHOULD BE ONE OF THE WARMEST DAYS OF THE SEASON AS
THE LOW LEVEL THERMAL RIDGE ADVECTS IN FROM THE SOUTHWEST.
WILL FEATURE AN INCREASING RISK FOR SHOWERS AND THUNDERSTORMS ON
LABOR DAY. MODELS VARY ON THE TIMING OF ANY PRECIPITATION. HOWEVER
GIVEN THE APPROACHING FRONT DURING THE AFTERNOON WILL ENCOUNTER AN
UNSTABLE AIRMASS...IS SEEMS THAT A RISK FOR THUNDERSTORMS WILL
EXIST. WILL HIGHLIGHT THE AFTERNOON FOR POSSIBLE THUNDERSTORMS.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 308 AM EDT SAT SEP 5 2015
MAIN FOCUS IS CURRENTLY ON THE THREAT FOR HEAVY RAINFALL MONDAY
NIGHT THROUGH TUESDAY NIGHT WITH SOME TRAINING THUNDERSTORMS
POSSIBLE IN ASSOCIATION WITH MAINLY UNIDIRECTIONAL WINDS IN THE
PROFILE...A VERY MOIST AIRMASS...AND A WARM FRONT LIFTING THROUGH
DURING THIS PERIOD. MANY AREAS NEAR AND NORTH OF I-96 ARE EXPECTED
TO RECEIVE ONE TO TWO INCHES OF RAIN BY WEDNESDAY MORNING WITH
HIGHER AMOUNTS QUITE POSSIBLE.
I BELIEVE THERE ARE SOME KEY INGREDIENTS COMING IN PLACE FOR LOCALLY
EXCESSIVE RAINFALL ACROSS WEST CENTRAL AND SOUTHWEST LOWER MI. AS
HAS BEEN MENTIONED MANY TIMES...A WEAK COLD FRONT WILL WASH OUT
ACROSS THE CWA MONDAY...WHICH WILL BECOME STATIONARY AND THEN LIFT
NORTH AS A WARM FRONT TUESDAY. JUST HOW FAR NORTH THIS BOUNDARY
LIFTS IS QUESTIONABLE GIVEN NUMEROUS AREAS OF CONVECTION THAT COULD
SUPPRESS THE FRONT SOUTHWARD. CURRENTLY FAVORING THE ECMWF WITH THIS
SYSTEM GIVEN A FEW DIFFERENT GYRATIONS NOTED WITH THE GFS RECENTLY
WITH HOW QUICK THE BOUNDARY WILL MOVE THROUGH.
DEEP LAYER RH (H1000-H500) ON TUESDAY COULD TOP 90% FOR A GOOD
PORTION OF THE CWA...ESPECIALLY FROM GRR TO THE NORTH. ALL OF THE
MODELS ARE ALSO SHOWING SOME H1000-H700 WIND CONVERGENCE. A 20 KT
LLJ AT 00Z TUES STRENGTHENS TO 30-35 KT BY 00Z WED. HIGHER UP...WE
WILL BE SQUARELY IN THE RIGHT ENTRANCE REGION OF A 100 KT JET STREAK
AS H500 POSITIVE VORTICITY ADVECTION MOVES INTO THE CWA DURING THE
MORNING AND AFTERNOON HOURS. NEAR THE SURFACE...THE WARM FRONT WILL
BE DRAPED ACROSS THE CWA NEAR GRR AT 12Z TUESDAY...POSSIBLY LIFTING
NORTH TOWARD ROUTE 10 BY 18Z. DEW POINT READINGS AROUND 70 COUPLED
WITH PW VALUES OF 2.00-2.25" STRONGLY SUGGEST ANY STORMS WOULD BE
CAPABLE OF HEAVY DOWNPOURS. IF THE NWP SOLUTIONS CONTINUE SUPPORTING
THESE DETAILS...COULD FORESEE A FLOOD THREAT FOR AREAS THAT GET THE
MOST PERSISTENT RAINS.
IN TERMS OF ANY SEVERE WEATHER THREAT...IT IS UNCLEAR AT THIS TIME.
ONGOING CONVECTION EARLY TUESDAY COULD HAMPER ANY DESTABILIZATION
DURING THE AFTERNOON. SFC BASED CAPE IS NOT MUCH MORE THAN 1000 J/KG
FOR THE AREA ON TUESDAY...THOUGH BULK SHEAR IS LOOKING MUCH BETTER
OFF THE ECMWF AT AROUND 35-40 KTS. IT IS ALSO SHOWING 100-150 M2/S2
OF 0-1 KM HELICITY COURTESY OF THE WARM FRONT NEARBY. NOT OUT OF THE
QUESTION THERE COULD BE SOME STRONGER STORMS CAPABLE OF GUSTY WINDS
AND SOME HAIL IF WE CAN DESTABILIZE SUFFICIENTLY.
BEYOND THIS PERIOD...LOOKING AT A PATTERN CHANGE FOR THE SECOND HALF
OF THE WEEK AND THE WEEKEND IN PARTICULAR. TROPICAL STORM IGNACIO
WILL GET SWEPT UP IN MID LEVEL FLOW OVER THE GULF OF ALASKA.
FOLLOWING THE ECMWF H500 HEIGHT FIELD...THIS HELPS DIG A TROUGH INTO
THE GREAT LAKES FOR FRIDAY AND SATURDAY...WITH CHILLY TEMPS AND
SCATTERED SHOWERS EXPECTED BY SATURDAY WITH HIGHS STRUGGLING INTO
THE 60S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 157 PM EDT SAT SEP 5 2015
VFR CONDITIONS WILL PREVAIL THROUGH THE AFTERNOON WITH ONLY A FEW
ISOLATED AREAS OF IFR WITH SHOWERS AND THUNDERSTORMS. AREAS OF IFR
IN FOG IS EXPECTED ONCE AGAIN TONIGHT. WINDS WILL BE FROM THE SOUTH
OR SOUTHWEST AOB 10 KNOTS.
&&
.MARINE...
ISSUED AT 308 AM EDT SAT SEP 5 2015
WINDS AND WAVES INCREASE SUNDAY INTO SUNDAY NIGHT AS THE WARM AIR
ADVECTION STRENGTHS AHEAD OF THE APPROACHING COLD FRONT. WILL NEED
TO MONITOR LITTLE AND BIG SABLE POINTS FOR A POSSIBLE SMALL CRAFT
ADVISORY AND ASSOCIATED BEACH HAZARDS. RIGHT NOW I HAVE WAVES
INCREASING TO 2 TO 4 FEET.
&&
.HYDROLOGY...
ISSUED AT 1214 AM EDT SAT SEP 5 2015
LOCALIZED HEAVY RAINFALL HAS FALLEN OVER SOUTHERN PORTIONS OF THE
FORECAST AREA THIS MORNING. RADAR ESTIMATES SHOW MOST OF THE
RAINFALL ALONG AND SOUTH OF I-96 WITH SPOTTY ESTIMATES POSSIBLY
EXCEEDING ONE INCH. THOUGH THIS IS NOT AN IMMEDIATE PLAYER IN ANY
RIVER FLOODING IT COULD PLAY A ROLE IN NEXT WEEKS RAINFALL
POTENTIAL.
A BRIEF DRY PERIOD LATE TONIGHT THROUGH THE EARLY HALF OF MONDAY
WILL HELP IN ALLOWING RUNOFF TO MAKE ITS WAY DOWN STREAMS AND
RIVERS. THIS MAY BE BENEFICIAL IN THE EVENT THAT THE LATE MONDAY
THROUGH WEDNESDAY TIMEFRAME BRINGS HEAVY RAIN. THOUGH QUESTIONS
STILL EXIST IN PLACEMENT...IT IS BECOMING MORE EVIDENT THAT
MOISTURE FLOWS IN THIS DIRECTION AS PWATS APPROACH 2.0 INCHES.
THIS COUPLED WITH THE SLOW MOVEMENT OF THE FRONTAL BOUNDARY MAY
AID IN ROUNDS OF HEAVY RAINFALL ALONG THE BOUNDARY THROUGH
PORTIONS OF THE FORECAST AREA. WHILE EVERYONE HAS THE THE
POTENTIAL TO SEE SOME DECENT RAINFALL...SOME LOCATIONS MAY EASILY
ACCUMULATE AN INCH OR MORE IN OR AROUND THUNDERSTORMS. ANY
PREVIOUS RAINFALL FROM TODAY COULD HAVE DEPOSITED ENOUGH MOISTURE
TO SOUTHERN SECTIONS... ALLOCATING ADDITIONAL RAINFALL MORE SO TO
RUNOFF THAN TO GROUND WATER. SO THE PLACEMENT OF THE HEAVY RAIN
NEXT WEEK IS SOMETHING TO WATCH.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...NJJ
SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...HOVING
AVIATION...OSTUNO
HYDROLOGY...JAM
MARINE...MJS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1214 PM EDT SAT SEP 5 2015
LATEST UPDATE...
HYDRO
.SYNOPSIS...
ISSUED AT 308 AM EDT SAT SEP 5 2015
A WARM FRONT WILL LIFT NORTHWARD THROUGH THE REGION TODAY LEADING
TO SOME SHOWERS AND THUNDERSTORMS. HIGH PRESSURE CONTROLS OUR
WEATHER ON SUNDAY WHICH SHOULD END UP A MOSTLY DRY AND VERY WARM
DAY. THE CHANCES FOR SHOWERS AND THUNDERSTORMS WILL INCREASE AS WE
GO THROUGH LABOR DAY AND INTO TUESDAY AS A SLOW MOVING COLD FRONT
NEARS FROM THE WEST. THE TEMPERATURES WILL STILL END UP WELL ABOVE
NORMAL EARLY NEXT WEEK.
&&
.UPDATE...
ISSUED AT 1039 AM EDT SAT SEP 5 2015
WE HAVE UPDATED TO FCST THIS MORNING TO EXTEND THE DENSE FOG
ADVISORY UNTIL NOON UP NORTH. WE HAVE ALSO INCREASED THE
SHOWER/STORM CHCS DOWN SOUTH WITH PLENTY OF COVERAGE ALREADY IN
PLACE DOWN THERE.
THE FOG UP NORTH HAS BEEN SLOW TO DISSIPATE THIS MORNING WITH MANY
LOCATIONS STILL AT 1/4SM OR LESS LEADING UP TO THE INITIAL
EXPIRATION TIME OF 10 AM THIS MORNING. WITH A LACK OF WIND TO MIX
THINGS UP AND PLENTY OF STRATUS IN PLACE...IT WILL TAKE A LITTLE
LONGER THAN PREVIOUSLY EXPECTED TO MIX IT OUT. WE GAVE IT UNTIL
NOON FOR MORE OF A BUFFER. WE WILL CANCEL IT EARLY IF ALL SITES
COME UP SOONER.
PLENTY OF SHOWERS AND STORMS ACROSS THE SOUTH THIS MORNING. THE
PESKY WEAK UPPER LOW THAT HAS BEEN MEANDERING ACROSS THE STATE THE
PAST COUPLE OF DAYS IS OVER LAKE MICHIGAN EARLY THIS MORNING. IT
NOW LOOKS LIKE IT IS MAKING A MOVE TO THE EAST...AND FIRING PLENTY
OF SHOWERS/STORMS AHEAD OF IT WITH THE MOIST AIR MASS IN PLACE.
IT APPEARS THIS WILL CONTINUE EAST THROUGH THE DAY AND PUSH THE
MORE WIDESPREAD COVERAGE EAST BY LATER THIS AFTERNOON. WE CAN NOT
RULE OUT A POP UP SHOWER/STORM WITH THE UPPER LOW STILL NEARBY.
WEAK SHEAR AND LIMITED INSTABILITY WILL KEEP THINGS GENERALLY
TAME. HEAVY DOWNPOURS WOULD BE THE GREATEST THREAT WITH THE SLOW
MOVEMENT.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 308 AM EDT SAT SEP 5 2015
DENSE FOG HAS BEEN INCREASING OVER THE PAST FEW HOURS AND NOW
COVERS MUCH OF THE REGION. HRRR RUC SUGGESTS THE FOG WILL PERSIST
THROUGH DAYBREAK. WILL GO WITH AN ADVISORY AND CARRY IT UNTIL MID
MORNING. WE MAY SEE GRADUAL IMPROVEMENT IN THE VISIBILITIES FROM
SOUTH TO NORTH BEFORE DAYBREAK AS THE ELEVATED WARM FRONT MOVES
IN.
THE ATMOSPHERE WILL BE UNSTABLE THROUGH THE DAY. SOME LIFT ARRIVES
WITH THE ELEVATED WARM FRONT MOVING IN THIS MORNING FROM THE
SOUTH. THEREFORE WILL KEEP THE MENTION OF SHOWERS AND
THUNDERSTORMS IN THE FORECAST. LITTLE OR NO FORCING IS AROUND
TONIGHT INTO SUNDAY. WILL KEEP IT DRY FOR NOW. THE ATMOSPHERE
BECOMES RATHER UNSTABLE ON SUNDAY...SO WILL NEED TO MONITOR THIS
CLOSELY. SUNDAY SHOULD BE ONE OF THE WARMEST DAYS OF THE SEASON AS
THE LOW LEVEL THERMAL RIDGE ADVECTS IN FROM THE SOUTHWEST.
WILL FEATURE AN INCREASING RISK FOR SHOWERS AND THUNDERSTORMS ON
LABOR DAY. MODELS VARY ON THE TIMING OF ANY PRECIPITATION. HOWEVER
GIVEN THE APPROACHING FRONT DURING THE AFTERNOON WILL ENCOUNTER AN
UNSTABLE AIRMASS...IS SEEMS THAT A RISK FOR THUNDERSTORMS WILL
EXIST. WILL HIGHLIGHT THE AFTERNOON FOR POSSIBLE THUNDERSTORMS.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 308 AM EDT SAT SEP 5 2015
MAIN FOCUS IS CURRENTLY ON THE THREAT FOR HEAVY RAINFALL MONDAY
NIGHT THROUGH TUESDAY NIGHT WITH SOME TRAINING THUNDERSTORMS
POSSIBLE IN ASSOCIATION WITH MAINLY UNIDIRECTIONAL WINDS IN THE
PROFILE...A VERY MOIST AIRMASS...AND A WARM FRONT LIFTING THROUGH
DURING THIS PERIOD. MANY AREAS NEAR AND NORTH OF I-96 ARE EXPECTED
TO RECEIVE ONE TO TWO INCHES OF RAIN BY WEDNESDAY MORNING WITH
HIGHER AMOUNTS QUITE POSSIBLE.
I BELIEVE THERE ARE SOME KEY INGREDIENTS COMING IN PLACE FOR LOCALLY
EXCESSIVE RAINFALL ACROSS WEST CENTRAL AND SOUTHWEST LOWER MI. AS
HAS BEEN MENTIONED MANY TIMES...A WEAK COLD FRONT WILL WASH OUT
ACROSS THE CWA MONDAY...WHICH WILL BECOME STATIONARY AND THEN LIFT
NORTH AS A WARM FRONT TUESDAY. JUST HOW FAR NORTH THIS BOUNDARY
LIFTS IS QUESTIONABLE GIVEN NUMEROUS AREAS OF CONVECTION THAT COULD
SUPPRESS THE FRONT SOUTHWARD. CURRENTLY FAVORING THE ECMWF WITH THIS
SYSTEM GIVEN A FEW DIFFERENT GYRATIONS NOTED WITH THE GFS RECENTLY
WITH HOW QUICK THE BOUNDARY WILL MOVE THROUGH.
DEEP LAYER RH (H1000-H500) ON TUESDAY COULD TOP 90% FOR A GOOD
PORTION OF THE CWA...ESPECIALLY FROM GRR TO THE NORTH. ALL OF THE
MODELS ARE ALSO SHOWING SOME H1000-H700 WIND CONVERGENCE. A 20 KT
LLJ AT 00Z TUES STRENGTHENS TO 30-35 KT BY 00Z WED. HIGHER UP...WE
WILL BE SQUARELY IN THE RIGHT ENTRANCE REGION OF A 100 KT JET STREAK
AS H500 POSITIVE VORTICITY ADVECTION MOVES INTO THE CWA DURING THE
MORNING AND AFTERNOON HOURS. NEAR THE SURFACE...THE WARM FRONT WILL
BE DRAPED ACROSS THE CWA NEAR GRR AT 12Z TUESDAY...POSSIBLY LIFTING
NORTH TOWARD ROUTE 10 BY 18Z. DEW POINT READINGS AROUND 70 COUPLED
WITH PW VALUES OF 2.00-2.25" STRONGLY SUGGEST ANY STORMS WOULD BE
CAPABLE OF HEAVY DOWNPOURS. IF THE NWP SOLUTIONS CONTINUE SUPPORTING
THESE DETAILS...COULD FORESEE A FLOOD THREAT FOR AREAS THAT GET THE
MOST PERSISTENT RAINS.
IN TERMS OF ANY SEVERE WEATHER THREAT...IT IS UNCLEAR AT THIS TIME.
ONGOING CONVECTION EARLY TUESDAY COULD HAMPER ANY DESTABILIZATION
DURING THE AFTERNOON. SFC BASED CAPE IS NOT MUCH MORE THAN 1000 J/KG
FOR THE AREA ON TUESDAY...THOUGH BULK SHEAR IS LOOKING MUCH BETTER
OFF THE ECMWF AT AROUND 35-40 KTS. IT IS ALSO SHOWING 100-150 M2/S2
OF 0-1 KM HELICITY COURTESY OF THE WARM FRONT NEARBY. NOT OUT OF THE
QUESTION THERE COULD BE SOME STRONGER STORMS CAPABLE OF GUSTY WINDS
AND SOME HAIL IF WE CAN DESTABILIZE SUFFICIENTLY.
BEYOND THIS PERIOD...LOOKING AT A PATTERN CHANGE FOR THE SECOND HALF
OF THE WEEK AND THE WEEKEND IN PARTICULAR. TROPICAL STORM IGNACIO
WILL GET SWEPT UP IN MID LEVEL FLOW OVER THE GULF OF ALASKA.
FOLLOWING THE ECMWF H500 HEIGHT FIELD...THIS HELPS DIG A TROUGH INTO
THE GREAT LAKES FOR FRIDAY AND SATURDAY...WITH CHILLY TEMPS AND
SCATTERED SHOWERS EXPECTED BY SATURDAY WITH HIGHS STRUGGLING INTO
THE 60S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 730 AM EDT SAT SEP 5 2015
SCATTERED THUNDERSTORMS THIS MORNING WILL IMPACT SOME OF THE TAF
SITES AS A WARM FRONT PUSHES NORTH. WIDESPREAD DENSE FOG WILL
LIFT SLOWLY NORTH AND DISSIPATE THIS MORNING. GENERALLY VFR
WEATHER THEN SETS UP IN AN UNSTABLE AIRMASS. SO WILL MAINTAIN A
RISK FOR THUNDERSTORMS...AS VCTS. TONIGHT THE RISK FOR
THUNDERSTORMS LOWERS...BUT WE MAY SEE FOG REFORMING ONCE AGAIN.
&&
.MARINE...
ISSUED AT 308 AM EDT SAT SEP 5 2015
WINDS AND WAVES INCREASE SUNDAY INTO SUNDAY NIGHT AS THE WARM AIR
ADVECTION STRENGTHS AHEAD OF THE APPROACHING COLD FRONT. WILL NEED
TO MONITOR LITTLE AND BIG SABLE POINTS FOR A POSSIBLE SMALL CRAFT
ADVISORY AND ASSOCIATED BEACH HAZARDS. RIGHT NOW I HAVE WAVES
INCREASING TO 2 TO 4 FEET.
&&
.HYDROLOGY...
ISSUED AT 1214 AM EDT SAT SEP 5 2015
LOCALIZED HEAVY RAINFALL HAS FALLEN OVER SOUTHERN PORTIONS OF THE
FORECAST AREA THIS MORNING. RADAR ESTIMATES SHOW MOST OF THE
RAINFALL ALONG AND SOUTH OF I-96 WITH SPOTTY ESTIMATES POSSIBLY
EXCEEDING ONE INCH. THOUGH THIS IS NOT AN IMMEDIATE PLAYER IN ANY
RIVER FLOODING IT COULD PLAY A ROLE IN NEXT WEEKS RAINFALL
POTENTIAL.
A BRIEF DRY PERIOD LATE TONIGHT THROUGH THE EARLY HALF OF MONDAY
WILL HELP IN ALLOWING RUNOFF TO MAKE ITS WAY DOWN STREAMS AND
RIVERS. THIS MAY BE BENEFICIAL IN THE EVENT THAT THE LATE MONDAY
THROUGH WEDNESDAY TIMEFRAME BRINGS HEAVY RAIN. THOUGH QUESTIONS
STILL EXIST IN PLACEMENT...IT IS BECOMING MORE EVIDENT THAT
MOISTURE FLOWS IN THIS DIRECTION AS PWATS APPROACH 2.0 INCHES.
THIS COUPLED WITH THE SLOW MOVEMENT OF THE FRONTAL BOUNDARY MAY
AID IN ROUNDS OF HEAVY RAINFALL ALONG THE BOUNDARY THROUGH
PORTIONS OF THE FORECAST AREA. WHILE EVERYONE HAS THE THE
POTENTIAL TO SEE SOME DECENT RAINFALL...SOME LOCATIONS MAY EASILY
ACCUMULATE AN INCH OR MORE IN OR AROUND THUNDERSTORMS. ANY
PREVIOUS RAINFALL FROM TODAY COULD HAVE DEPOSITED ENOUGH MOISTURE
TO SOUTHERN SECTIONS... ALLOCATING ADDITIONAL RAINFALL MORE SO TO
RUNOFF THAN TO GROUND WATER. SO THE PLACEMENT OF THE HEAVY RAIN
NEXT WEEK IS SOMETHING TO WATCH.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...NJJ
SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...HOVING
AVIATION...MJS
HYDROLOGY...JAM
MARINE...MJS
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
358 PM CDT SAT SEP 5 2015
.DISCUSSION...
Issued at 358 PM CDT SAT SEP 5 2015
Very warm and muggy conditions across the area this afternoon with
gusty winds in the 20 to 30 mph range. The resultant heat indices
have reached into the middle to upper 90s this afternoon. Satellite
imagery has indicated a well formed CU field across the entire area,
likely in response to the surface temperatures approaching or even
reaching convective temperature. A few storms have formed in central
Missouri across the far southeastern EAX zones, but this activity is
anticipated to be isolated in nature. There is no real surface
boundary, nor much in the way of upper level support as mid level
pressure heights are actually rising a bit through the afternoon.
Have introduced some low end SChc PoPs for the southeastern zones
for this concern. Otherwise, RAP forecast soundings indicate that
there is still a bit of a CAP over the area, so without any of the
aforementioned support for ascent it`s pretty unlikely that
convection will get going this afternoon. Expect a repeat on Sunday
of Saturday`s conditions with another day reaching the lower to
middle 90s, with moist conditions allowing heat indices to reach the
upper 90s to perhaps 100 degrees.
Large scale pattern change is in store for the late part of Sunday
into next week. The large ridge will ultimately break down as a
large trough moves into the northern plains. Ultimately a surface
boundary will slide into the area and be accompanied by decreasing
mid level pressure heights, allowing for convection to pick up first
across southeast Nebraska and southwest Iowa on Sunday night, then
eventually forming and moving into northwest Missouri. Thereafter
for the remainder of the Sunday through Wednesday time frame
increases mid level flow aloft as well as the boundary will bring
off and on chances for rain through the first half of next week. The
formation of 1 or more MCS`s look to be likely, mainly north of I-70
for the Sunday night through Tuesday night period, with perhaps a
couple rounds of very heavy rain across far northern Missouri into
southern Iowa. Chances for rain will generally slide south with the
boundary as the week progresses. Instability and shear don`t look to
be astronomically high, however there will likely be enough of both
parameters to warrant at least a concern for some marginally
organized storm formations, that could bring some wind along with
the heavy rain threat. Perhaps the most concerning aspect of this
event will be the potential for heavy rain. PWAT values across
northern Missouri could approach or even surpass 2 inches, which is
incredibly high for the early September time period. There is
certainly some concern for some flooding and flash flooding as a
result of repeated rounds of heavy rain through mid week. By
Wednesday evening, the boundary looks like it`ll be south of the
forecast area, with a more continental influenced air mass. The
result will be a drying out period and very comfortable temperatures
for the late part of the upcoming week, into the next weekend.
Expect Highs in the 80s for Thursday, then all the way down into the
upper 60s and lower 70s for late in the week into the Sat/Sun time
period.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon)
Issued at 106 PM CDT SAT SEP 5 2015
VFR expected for next 24 hours with winds diminishing over night
then picking back up on Sunday.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
DISCUSSION...Leighton
AVIATION...Leighton
AREA FORECAST DISCUSSION
NWS BILLINGS MT
422 PM MDT SAT SEP 5 2015
.UPDATE...
SFC LOW DEVELOPING IN NORTHERN WY IS ALLOWING FOR COOLER AIR TO
SURGE INTO OUR WESTERN ZONES...WITH A TEMP DOWN TO 48 AT JUDITH
GAP AND 63 AT BILLINGS. THIS HAS ELIMINATED ANY RISK OF SEVERE
STORMS FROM ROUNDUP-BILLINGS WESTWARD. MOST RECENT HRRR RUNS
SUGGEST STRONG STORMS DEVELOPING IN SOUTHERN BIG HORN COUNTY SOON
AND TRACKING ACROSS OUR SOUTHEAST THIS EVENING. THIS SEEMS TO BE A
REASONABLE SCENARIO AS WEAK COOL ADVECTION CONTINUES TO IMPACT
MORE NORTHERN LOCATIONS SUCH AS HYSHAM...FORSYTH AND MILES CITY...
WHERE LATEST MESOANALYSIS SHOWS QUITE A BIT OF CIN.
JKL
&&
.SHORT TERM...VALID FOR SUN AND MON...
CONDITIONS STILL FAVORABLE FOR A PERIOD OF SEVERE WX LATE THIS
AFTERNOON AND EVENING AS APPROACHING PACIFIC TROF INTERACTS WITH A
MOIST AND UNSTABLE AIRMASS WITH AMPLE SHEAR. GREATEST SEVERE
POTENTIAL IS FROM BILLINGS EASTWARD FROM ABOUT 4 PM THRU MIDNIGHT.
LATEST HIGH RES MODELS SUGGEST SOME SLIGHT DEVIATIONS IN THE
LOCATION OF THE SEVERE POTENTIAL. DEPARTING ENERGY IN THE DAKOTAS
AND STRATUS OVER NE MT HAS RESULTED IN A LIGHT N-NW WIND FROM
FORSYTH TO MILES CITY...A MODEST STABILIZING WIND AND MILES CITY
REMAINS AT 67 DEGREES W/ AN MVFR CIG AS OF 3PM. LATEST NSSL-WRF
ALSO SHOWS GREATEST UPDRAFT HELICITY ACROSS SOUTHEAST MT AND THIS
SEEMS REASONABLE GIVEN GREATEST OBSERVED PRESSURE FALLS AND SFC
LOW IN NORTHEAST WY...WHERE DRIER MIXED SW WINDS HAVE DEVELOPED.
HRRR HAS THUS BEEN TRENDING SLIGHTLY SOUTH WITH DEVELOPMENT OF A
FEW STRONGER CELLS OVER THE NEXT FEW HOURS AND THIS SEEMS
REASONABLE GIVEN WHAT WE HAVE SEEN TODAY. SO GREATEST THREAT MAY
NOT BE FROM HYSHAM-FORSYTH-MLS BUT RATHER CLOSER TO HARDIN-LAME
DEER-BROADUS-EKALAKA-BAKER. BILLINGS IS ON THE WESTERN EDGE OF THE
THREAT. IT IS POSSIBLE THAT THE JUNKY CONVECTION CURRENTLY COMING
OFF THE BEARTOOTH ABSAROKAS WILL MUDDLE UP OUR AIRMASS ENOUGH TO
KEEP THE BETTER SEVERE POTENTIAL EAST OF BILLINGS...WHICH IS ALSO
A RECENT TREND OF THE HRRR. OVERALL IT IS A SOMEWHAT COMPLICATED
PICTURE OUT THERE AND PEOPLE WHO ARE OUTDOORS SHOULD STAY ALERT OF
THE WX FROM NOW THRU MIDNIGHT.
FURTHER WEST...WE ARE SEEING DRIER MIXED WINDS AT LIVINGSTON.
WHEREAS THIS GREATLY REDUCES THE SVR RISK ALONG THE FOOTHILLS THIS
AREA WILL BE PRONE TO SEE STRONG WIND GUSTS WITH ANY WEAK CELLS.
THIS INCLUDES LIVINGSTON WHERE FLOW ALOFT IS PARALLEL TO THE
PARADISE VALLEY...IE A PRIME SET UP FOR A STRONG CONVECTIVELY
INDUCED GAP WIND AT LVM.
DRIER WEST WINDS WILL PUSH ACROSS THE CWA LATE TONIGHT AND PCPN
SHOULD EXIT OUR EAST BY 12Z. A MUCH DRIER AND COOLER-THAN-NORMAL
REGIME CAN BE EXPECTED MONDAY AND TUESDAY...WITH HIGH TEMPS
RANGING FROM THE MID 60S TO MID 70S AND FAIRLY CHILLY LOWS MOSTLY
IN THE UPPER 30S AND 40S. WEAK SHORTWAVE SUNDAY NIGHT WILL HAVE
VERY LITTLE MOISTURE TO WORK WITH SO WILL KEEP FORECAST DRY.
STRONGER ENERGY WILL HAVE A BETTER CHANCE OF PRODUCING SOME LIGHT
SHOWERS MONDAY NIGHT AND HAVE ADDED A LOW POP IN WEST AND CENTRAL
PARTS TO COVER THIS. THIS IS WELL AGREED UPON BY THE GFS...ECMWF
AND CANADIAN MODELS.
JKL
.LONG TERM...VALID FOR TUE...WED...THU...FRI...SAT...
MADE A FEW MINOR CHANGES THE EXTENDED FORECAST PERIOD...BUT
OVERALL THE STORY REMAINS THE SAME...WITH GENERALLY QUIET AND
MAINLY DRY WEATHER THROUGH NEXT WEEK.
TEMPS ARE LOOKING SLIGHTLY COOLER OVERALL THAN PREVIOUS MODELS
INDICATED...DUE TO A SUCCESSION OF SHORTWAVES BRINGING REINFORCING
SHOTS OF COOL AIR. MORNINGS LOWS IN THE 40S F MOST NIGHTS...AND
HIGHS BETWEEN 65 AND 75 F THROUGH THURSDAY. TEMPS CLIMB BACK TO
AROUND NORMAL OR EVEN SLIGHTLY ABOVE FOR FRIDAY AND SATURDAY.
AS MENTIONED...MAINLY DRY CONDITIONS WILL PREVAIL THROUGH THE
PERIOD...IN GENERALLY DRY AIRMASS...BUT DID ADD POPS FOR TUESDAY
MORNING...AND THROUGH THE DAY WEDNESDAY. A SHORTWAVE IS EXITING
THE REGION TUESDAY MORNING...AND A COUPLE MORE APPEAR TO CROSS THE
REGION WEDNESDAY MORNING AND EVENING. MODELS HAVE BEEN TRENDING
STRONGER AND WETTER WITH THESE WAVES OVER PAST COUPLE OF RUNS...SO
DID NOT FEEL COMFORTABLE LEAVING COMPLETELY DRY. AAG
&&
.AVIATION...
MVFR CIGS CONTINUE IN EXTREME EASTERN MONTANA...WITH IMPROVING
CIGS FROM KSHR TO KBIL AND WEST. A FEW SHOWERS ARE DEVELOPING
WEST OF KBIL...INCLUDING KLVM...AND ARE POSSIBLE THROUGH MID
AFTERNOON. STRONGER STORMS ARE EXPECTED TO BEGIN DEVELOPING BY 22Z
AND MOVE ACROSS SOUTH CENTRAL AND SOUTHEASTERN MT THROUGH THE
EVENING HOURS. MVFR TO IFR CONDITIONS WITH HEAVY RAIN...STRONG
WINDS...AND LARGE HAIL ARE POSSIBLE WITH THE STRONGEST STORMS.
FINALLY...AREA MOUNTAINS WILL BE FREQUENTLY OBSCURED THROUGH THIS
EVENING. AAG
&&
.PRELIMINARY POINT TEMP/POPS...
SUN MON TUE WED THU FRI SAT
-----------------------------------------------------------
BIL 048/073 044/071 045/074 048/070 046/071 046/078 051/080
60/N 00/B 22/W 22/T 21/B 11/U 11/U
LVM 043/069 035/068 039/072 043/071 042/073 044/079 046/080
30/N 01/B 22/W 22/T 21/U 11/U 10/U
HDN 048/073 042/072 042/075 047/072 045/072 045/079 049/082
80/N 00/B 22/W 22/T 21/B 11/U 11/U
MLS 052/072 044/071 045/074 049/070 044/069 045/076 049/080
80/N 00/B 12/W 22/T 21/B 10/U 00/U
4BQ 052/071 043/071 046/074 050/071 047/070 046/075 050/079
70/N 00/B 12/W 22/T 21/B 10/U 00/U
BHK 053/070 043/070 043/072 047/069 043/067 041/072 047/077
70/N 01/B 02/W 22/T 21/B 10/U 11/U
SHR 047/071 038/072 041/074 044/072 042/070 042/076 046/080
30/B 00/B 12/W 22/T 21/B 11/U 11/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
134 PM CDT SAT SEP 5 2015
.SYNOPSIS...
ISSUED AT 400 AM CDT SAT SEP 5 2015
WEAK EMBEDDED SHORT WAVE MOVING QUICKLY ACROSS THE CENTRAL
ROCKIES AND ONTO THE HIGH PLAINS IN SWRLY FLOW ALOFT WORKING IN
CONCERT WITH LLJ TO GENERATE SHRA AND ISOLD TSRA ACROSS PORTIONS
OF WRN NEB EARLY THIS MORNING. MEANWHILE UPPER TROUGH AND
ASSOCIATED LOW OVER THE PAC NW STARTING TO MOVE EWD WHILE HEIGHTS
RISE ACROSS THE PLAINS. THESE TWO THINGS CONTRIBUTING TO
TIGHTEN/INCREASE THE UPPER FLOW AHEAD OF THE LOW IN THE NW.
MOISTURE AND ASSOCIATED CONVECTIVE ACTIVITY FROM TROPICAL STORM
KEVIN MOVING ONSHORE ON THE BAJA PENINSULA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 400 AM CDT SAT SEP 5 2015
FORECAST ISSUES FOR EARLY THIS MORNING INVOLVES THE POTENTIAL FOR
ADDITIONAL CONVECTIVE DEVELOPMENT IN SRN/WRN NEB WHICH SEVERAL OF
THE CAMS SUGGEST WILL HAPPEN THROUGH THE MORNING. RADAR ECHOES
OVER THE LAST FEW HOURS HAVE INCREASED IN THE ERN PANHANDLE...BUT
NEW DEVELOPMENT AS PER THE OPERATIONAL HRRR HAS YET TO OCCUR
ASSOCIATED WITH THE NWD ADVANCING WARM FRONT OVER SRN NEB. SHORT
RANGE MODELS DO HAVE ELEVATED INSTABILITY PRESENT AND SPC
MESOANALYSIS BASED ON RAP SHOWS DEEP MOIST CONVERGENCE INCREASING
TO SUPPORT THIS IDEA. HAVE TRENDED THE HOURLY POP GRIDS TO
REFLECT THIS OCCURRING...DESPITE EXP HRRR AND NSSL WRF NOT
EVOLVING IN THIS MANNER.
ATTENTION THEN TURNS TO ADDITIONAL TSRA DEVELOPMENT THIS
AFTERNOON. AS PREVIOUSLY MENTIONED SHORT WAVE CONTINUES TO MOVE
NEWD INTO THE DAKOTAS TODAY...WEAK LARGE SCALE HEIGHT FALLS ALSO
MOVE OUT OF THE AREA. HOWEVER AS PAC NW UPPER LOW CONTINUES TO
MOVE EWD GOOD HEIGHT FALLS DEVELOP ACROSS WRN MT. THE INCREASED
SWRLY FLOW AHEAD OF THIS FEATURE ALLOWS THE SFC LOW TO REDEVELOP
OVER ERN WY THIS AFTERNOON. AS THIS OCCURS...DEEPER MIXING SOUTH
OF THE SFC LOW WILL DEVELOP THIS AFTERNOON SERVING TO LOWER DEW
POINTS ACROSS THE PANHANDLE. AT THIS SAME TIME...INCREASING SERLY
LOW LEVEL FLOW IN THE TIGHTENING SFC GRADIENT WILL INCREASE DEW
POINTS/LOW LEVEL MOISTURE FURTHER EAST OVER TIME. THE RESULT IS
TO TIGHTEN THE GRADIENT AND EVENTUALLY TO DEVELOP THUNDERSTORMS
ASSOCIATED WITH THIS BOUNDARY. SUITE OF MODELS CONTAIN A WIDE
VARIETY OF SOLUTIONS HOWEVER IN HOW EXTENSIVE THE QPF WILL
BE...IF AT ALL. NAM SUGGESTS A LARGE INCREASE IN PW BY AFTERNOON
/PRIOR TO CONVECTIVE DEVELOPMENT IN THE MODEL/ ASSOCIATED WITH
THE FETCH OF MID/UPPER LEVEL MOISTURE ORIGINATING FROM THE ERN
PAC TROPICS VIA THE SWRLY FLOW. IF DEEP MOIST CONVECTION CAN
DEVELOP...THE WARM MOIST MID LEVELS WOULD ALLOW FOR A CAPE
PROFILE MORE CONDUCIVE TO HEAVY RAIN PRODUCING STORMS AND SHEAR
OF 25-30KTS WOULD BE MARGINAL FOR DEVELOPING STRONG STORMS. AS
ALWAYS HOWEVER SMALL SCALE STORM INTERACTIONS MAY ALLOW FOR MORE
ROBUST DEVELOPMENT ON OCCASION.
TEMPERATURES TODAY WILL BE TRICKY DUE TO LEFT OVER CLOUD COVER
FROM ONGOING CONVECTION AS WELL AS NEW CLOUD COVER FROM
ADDITIONAL DEVELOPMENT THIS AFTERNOON. ASSUMING SRN AREAS WOULD
RECEIVE BEST INSOLATION FOR A LONGER PERIOD OF TIME AND THEREFORE
MAXES ARE HIGHER THERE...THOUGH 90S WILL AGAIN BE COMMON TODAY.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 400 AM CDT SAT SEP 5 2015
SOUTHWEST FLOW TO START THE WEEK TRANSITIONS TO MORE ZONAL FLOW AS
AN UPPER LEVEL LOW LIFTS ACROSS THE NORTHERN ROCKIES INTO THE
CANADIAN PLAINS. A COUPLE OF COLD FRONTS WILL RESULT IN FALLING
TEMPS FOR THE WEEK. MAIN CONCERN IN THE EXTENDED WILL BE TIMING THE
COOL DOWNS AND LOW POP CHANCES THROUGHOUT THE PERIOD.
SUNDAY INTO MONDAY SW FLOW WILL TAP SOME PACIFIC MOISTURE. MODELS
SHOWING SOME MOISTURE FROM THE EASTERN PACIFIC TROPICAL SYSTEMS
GET DRAWN ACROSS THE 4 CORNERS AND TOWARDS THE HIGH PLAINS. THIS
MAY BE ENOUGH TO INCREASE THE MOISTURE IN THE MID/UPPER LEVELS THAT
CAN BE TAPPED BY WEAK DISTURBANCES RIDING ACROSS THE AREA. MODELS
HAVE INCREASE THE LIGHT QPF OVER THE CWA AND CAN NOT ARGUE
NEEDING LOW POPS WITH EACH PASSING WAVE.
MID WEEK A COLD FRONT WILL PUSH ACROSS THE AREA. TIMING OF THE
FRONT AND BETTER MOISTURE RESULTS IN BEST CHANCE FOR PRECIP TO BE
ACROSS THE EASTERN ZONES. BEHIND THE FRONT TEMPS COOL INTO THE
70S...WHICH WOULD BE BELOW NORMAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 102 PM CDT SAT SEP 5 2015
MID AND UPPER LEVEL MOISTURE IN THE FORM OF MID AND HIGH LEVEL
CLOUDINESS CONTINUES TO STREAM NORTHEAST ACROSS THE AREA. A FEW
SCATTERED SHOWERS OR TSTMS COULD DEVELOP FROM THE MID CLOUD DECK
THIS AFTERNOON INTO TONIGHT. GENERALLY EXPECT VFR
CONDITIONS...WITH SOUTH WINDS 10 TO 20 KTS TODAY INTO
TONIGHT...SHIFTING TO THE NORTHWEST AT 10 TO 20 KTS SUNDAY AS
COLD FRONT CROSSES THE AREA.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JWS
SHORT TERM...JWS
LONG TERM...MASEK
AVIATION...TAYLOR
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
935 AM PDT SAT SEP 5 2015
.SYNOPSIS...A FEED OF TROPICAL MOISTURE INTO ARIZONA WILL STILL
ALLOW FOR A SHOWER OR THUNDERSTORM AROUND THROUGH TUESDAY. OTHERWISE
A STORM SYSTEM PASSING ACROSS NEVADA TODAY WILL RESULT IN ANOTHER
DAY OF GUSTY SOUTH TO SOUTHWEST WINDS ACROSS THE AREA ESPECIALLY IN
LINCOLN COUNTY. WINDS WILL DECREASE IN ALL AREAS ON SUNDAY.
TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH THE WEEKEND THEN
RETURN TO ABOVE NORMAL BY THE END OF NEXT WEEK.
&&
.UPDATE...OVERALL THE FORECAST IS IN GOOD SHAPE. I DID NUDGE POPS
UPWARDS ACROSS EASTERN MOHAVE COUNTY MAINLY EAST OF KINGMAN. MODELS
AGREE ON INSTABILITY AXIS ROUGHLY ALONG THE COLORADO RIVER AND
EASTWARD. WHILE SOUTHWEST FLOW WILL WORK TO BRING IN DRIER AIR TODAY
ENOUGH MOISTURE REMAINS IN PLACE FOR SOME ISOLATED ACTIVITY ACROSS
THESE AREAS LATER THIS AFTERNOON. COVERAGE HOWEVER WILL BE HIGHLY
ISOLATED AT BEST.
-OUTLER-
&&
.SHORT TERM...TODAY THROUGH SUNDAY NIGHT.
A SOUTHWEST FLOW ALOFT WAS TRANSPORTING A FEED OF TROPICAL MOISTURE
NORTHEAST TOWARD ARIZONA THIS MORNING. THIS IS EVIDENT FROM
INSPECTING INFRARED SATELLITE IMAGERY AS ONE CAN SEE AN EXTENSIVE
AMOUNT OF CLOUDS ACROSS THE EASTERN TWO-THIRDS OF THE STATE. OUR
AREA WILL BE ON THE EDGE OF THIS MOISTURE FEED BUT WE NEVER REALLY
APPEAR TO SHAKE IT AWAY ALTOGETHER DESPITE AN APPROACHING MID/UPPER
LEVEL TROUGH WORKING INTO CALIFORNIA AND WESTERN NEVADA. AS A RESULT
ONCE AGAIN TODAY WE SHOULD STAND THE PROSPECT OF SEEING CUMULUS POP
UP IN EASTERN MOHAVE COUNTY AND POSSIBLY A SHOWER OR THUNDERSTORM
ESPECIALLY TOWARD THE MOUNT TRUMBULL AREA. THE HRRR STILL SHOWS SOME
WEAK RETURNS THIS AFTERNOON AS FAR WEST AS THE COLORADO RIVER BUT
THE DRIER AIR ADVANCING EAST ON WATER VAPOR RESULTS IN MY THOUGHT
THAT AT BEST THIS WOULD BE A FEW CUMULUS.
THERE IS STILL A BELT OF STRONGER WINDS ALOFT COURTESY OF THE JET
STREAM CROSSING THE EASTERN PARTS OF THE AREA TODAY. HOWEVER,
SEVERAL FACTORS DO NOT SUPPORT WINDS AS STRONG TODAY. THE SURFACE
PRESSURE GRADIENT IS VERY, VERY WEAK AND NOT EVEN ON PAR WITH WHAT
WE WOULD SEE ON A NORMAL DAY WITH JUST THERMALS. SECONDLY, THE 700
MB WINDS ON THE GFS AND ECMWF ARE MUCH LOWER TODAY - ABOUT 20 TO 25
KTS. AS A RESULT, I HAVE CANNED THE WIND ADVISORIES FOR NORTHEAST
CLARK AND NORTHERN MOHAVE COUNTY. IN LINCOLN COUNTY, THERE IS SOME
HOPE THAT WE MAY SEE A FEW POCKETS IN EASTERN AREAS REACH THE 40 MPH
GUST MARK FOR 3 HOURS SUCH AS PANACA SUMMIT, EAGLE VALLEY, SPRING
VALLEY STATE PARK AND BEAVER DAM. THUS THE WIND ADVISORY REMAINS IN
EFFECT THERE FOR LATE THIS MORNING THROUGH EARLY THIS EVENING.
TEMPS WILL DROP A FEW DEGREES TODAY BUT WE STILL LEANED TOWARD THE
WARMER END OF GUIDANCE FOR HIGHS. LOWS TONIGHT WERE TWEAKED UP A BIT
BASED ON A BLEND OF THE LATEST GUIDANCE BUT IT WILL STILL BE A
REFRESHING NIGHT AND START TO SUNDAY WITH LESS WIND. SOME OF THE
COLDER SPOTS IN LINCOLN COUNTY LIKE SPRING VALLEY STATE PARK AND
URSINE MAY DROP INTO THE 30S AS WILL THE HIGHER SPOTS IN THE SIERRA
AND WHITE MOUNTAINS AS WELL AS WELL UP ON MOUNT CHARLESTON. BE
PREPARED FOR THE CHILL IF YOU PLAN TO CAMP.
THE TROUGH AXIS WILL SORT OF GET HUNG UP ACROSS SOUTH-CENTRAL NEVADA
ON SUNDAY BEFORE DISSOLVING. AS A RESULT, MOHAVE COUNTY REMAINS IN
ENOUGH OF A SOUTHWEST FLOW TO ENTRAIN MOISTURE ON IN AND THE CHANCE
OF A SHOWER OR THUNDERSTORM WAS ADDED AGAIN INTO EASTERN AREAS FOR
SUNDAY. THE REST OF THE CWFA LOOKS DRY. TEMPS WILL START TO REBOUND
AND JUMP UP A DEGREE OR TWO. WITH LESS UPPER LEVEL SUPPORT WINDS
WILL ALSO BE LIGHTER. OVERALL FOR MOST AREAS THIS WILL BE THE PICK
OF THE LABOR DAY WEEKEND FOR THE BEST WEATHER. SUNDAY NIGHT`S LOWS
WERE RAISED UP AS WELL SEVERAL DEGREES BASED ON THE LATEST GUIDANCE.
ENJOY THIS LITTLE BREAK FROM THE INTENSITY OF SUMMER.
.LONG TERM...MONDAY THROUGH SATURDAY.
THE MEDIUM RANGE MODELS INDICATE A GENERALLY DRY PATTERN FOR MOST OF
THE FORECAST AREA WITH A WARMING TREND THE SECOND HALF OF THE WEEK.
THERE IS SOME UNCERTAINTY WITH MOISTURE FORECASTS BETWEEN THE GFS
AND ECMWF BUT NEITHER SOLUTION DEPICTS SIGNIFICANT MOISTURE
SPREADING INTO THE AREA. THE GFS CONTINUES TO INDICATE LOW TO MID
LEVEL MOISTURE LINGERING OVER NORTHWEST ARIZONA THROUGH LABOR DAY
AND IT IS WORTH MENTIONING A SLIGHT CHANCE OF THUNDERSTORMS OVER THE
EASTERN HALF OF MOHAVE COUNTY. AN INCREASINGLY DRY WESTERLY FLOW
DEVELOPING TUESDAY SHOULD PUSH MOST OF THE MOISTURE TO THE EAST
TUESDAY BUT A SLIGHT CHANCE OF THUNDERSTORMS STILL EXISTS FOR THE
ARIZONA STRIP.
WE WILL NEED TO KEEP AN EYE ON ANOTHER TROPICAL SYSTEM NEAR SOUTHERN
BAJA WHICH THE MODELS INDICATE WILL DEVELOP AND MOVE TO THE WEST
NORTHWEST THOUGH THERE IS LITTLE CHANCE OF ANY SIGNIFICANT MOISTURE
BEING PULLED OUR WAY. THE WARMING TREND WILL COME DUE TO AN EASTERN
PACIFIC RIDGE MERGING WITH A RIDGE NEAR NORTHERN MEXICO EXPANDING TO
THE NORTHWEST AFTER WEDNESDAY. THE ECMWF SOLUTION IS A LITTLE WARMER
THAN THE GFS AND PROVIDES HIGH TEMPS SEVERAL DEGREES ABOVE NORMAL
WITH TRIPLE DIGIT READINGS BACK OVER MUCH OF THE MOJAVE DESERT
REGION FROM WEDNESDAY INTO NEXT WEEKEND.
&&
.AVIATION...FOR MCCARRAN...WINDS WILL AGAIN INCREASE LATE THIS
MORNING AND BE STRONGEST IN THE AFTERNOON AND EARLY EVENING GUSTING
OVER 20 KTS. THERE IS A SMALL WINDOW BETWEEN 14Z AND 17Z TODAY WHERE
WIND DIRECTION WILL BE NEAR THE 160 DEGREE LINE WHICH MAY CAUSE
CONFIGURATION ISSUES.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...THERE WILL AGAIN BE THE POSSIBILITY OF A SHRA/TSRA
TODAY AFTER 18Z AND BEFORE 06Z SUNDAY IN AND AROUND MT TRUMBILL. ALL
OTHER AREAS SHOULD BE DRY. OTHERWISE LOOK FOR SOUTH TO SOUTHWEST
WINDS INCREASING BETWEEN 16Z AND 20Z TODAY WITH GUSTS OF 20-30 KTS
EXCEPT IN LINCOLN COUNTY WHERE GUSTS TO AROUND 35 KTS ARE POSSIBLE.
WINDS WILL SLOWLY DECREASE BETWEEN 03Z AND 06Z SUNDAY. A CLEAR SKY
IS EXPECTED EXCEPT IN AREAS EAST AND NORTHEAST OF KIGM WHERE FEW-SCT
CLOUDS AOA 10K-15K FEET WILL BE AROUND IN THE AFTERNOON AND EARLY
EVENING.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
SHORT TERM/AVIATION...STACHELSKI
LONG TERM...ADAIR
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
316 PM MDT SAT SEP 5 2015
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS WILL CONTINUE THIS EVENING FAVORING THE
WESTERN TWO-THIRDS OF NEW MEXICO. A FEW STORMS MAY BRIEFING BECOME
STRONG WITH HEAVY RAIN AND SMALL HAIL. STARTING SUNDAY AND
CONTINUING INTO THE MIDDLE OF THE WEEK...A DRYING TREND WILL BE
IN STORE ACROSS AT LEAST THE NORTHERN HALF OF THE STATE. THIS WILL
GENERALLY CONFINE STORMS TO AREAS SOUTH OF INTERSTATE 40. ONE
EXCEPTION WILL BE A BACK DOOR FRONT THAT ARRIVES ON TUESDAY WHICH
MAY SPARK A FEW STORMS ACROSS NORTHEAST NEW MEXICO. A STRONGER
BACK DOOR FRONT LOOKS TO ARRIVE THURSDAY INTO FRIDAY...
SIGNIFICANTLY INCREASING STORM CHANCES...INITIALLY ACROSS EASTERN
NEW MEXICO...BUT EVENTUALLY ACROSS CENTRAL AND WESTERN NEW MEXICO
AS WELL.
&&
.DISCUSSION...
MID AND HIGH LEVEL CLOUDS CONTINUE TO INHIBIT INSTABILITY ACROSS
MUCH OF WESTERN NM...SIMILAR TO YESTERDAY...THANKS TO THE FORMER
TS KEVIN. HOWEVER...CLOUDS ARE BEGINNING TO THIN...AND WHERE THERE
ARE ENOUGH BREAKS IN THE CLOUDS FOR SOME INSOLATION...TSTMS HAVE
DEVELOPED. THE STRONGEST THUS FAR HAS BEEN BETWEEN NAVAJO DAM AND
DULCE...WHICH LIKELY PRODUCED SOME SMALL HAIL. FOR THE REST OF THE
EVENING...STORMS SHOULD CONTINUE THRU AT LEAST SUNSET...AND
QUICKLY DIMINISH IN COVERAGE THEREAFTER. LARGELY WENT WITH THE
HRRR FOR THE POP FORECAST TONIGHT...WHICH PLACES MUCH OF THE QPF
ACROSS THE NORTHERN MTNS AS A WEAK VORT MAX QUICKLY MOVES THRU THE
SW FLOW.
STILL LOOKS TO BE A FAIR AMOUNT OF CLOUD COVER ON SUNDAY...
DESPITE THE PLUME BECOMING LESS ORGANIZED. HOWEVER...THE CLOUD
COVER LOOKS LIKE IT MAY BE DISPLACED A BIT EASTWARD FROM WHERE IT
WAS LARGELY LOCATED TODAY. IF THIS IS THE CASE...A BIT MORE
CONVECTION WILL BE POSSIBLE FOR WESTERN NM.
DRIER MID LEVEL AIR STILL LOOKS LIKE IT WILL MOVE INTO NORTHERN
NM ON MONDAY...LIMITING CONVECTION A BIT MORE THAN ON SUNDAY
PERHAPS. HOWEVER...THOUGH THE GFS AND EC AGREE ON THIS...THE NAM
IS QUITE BULLISH AT BREAKING OUT PRECIP ACROSS MUCH OF THE EASTERN
TWO-THIRDS OF THE FORECAST AREA AS ANOTHER WEAK VORT MAX CROSSES
THE AREA. INCREASED POPS A BIT...BUT WOULD LIKE TO SEE MORE MODEL
CONSISTENCY BEFORE INCREASING POPS MUCH FURTHER.
MID LEVEL DRY AIR CONTINUES TO MOVE IN TO NW NM ON TUESDAY AS THE
UPPER CENTERS ITSELF SOUTH OF THE STATE ALLOWING FOR MORE WESTERLY
FLOW OVER NM. THIS SHOULD AGAIN KEEP THE HIGHEST CHANCES FOR
PRECIP SOUTH OF I-40...HOWEVER A BACK DOOR COLD FRONT WILL NUDGE
INTO NE NM WHICH MAY SPARK A FEW STORMS IF THE MID LEVEL DRYING IS
NOT OVERWHELMING.
DRIER CONDITIONS WILL PERSIST ACROSS MUCH OF WESTERN AND EVEN
PORTIONS OF CENTRAL NM WED AND THURS WHILE ACROSS THE EAST...AS
THE FRONT WASHES OUT...SOME GULF MOSITRUE SHOULD BE PULLED INTO
THE EASTERN PLAINS. A STRONGER BACK DOOR FRONT LOOKS TO ARRIVE
AROUND THE THURS NIGHT TIME FRAME...WHICH BOTH THE EC AND GFS
SUGGEST COULD BRING SOME DECENT QPF TO AT LEAST EASTERN NM. THE
FRONT LOOKS TO PUSH THRU THE GAPS OF THE CENTRAL MTN CHAIN THURS
NIGHT/FRI MORNING...SETTING THE STAGE FOR A GREATER COVERAGE OF
TSTMS DURING FRIDAY/SATURDAY PERIOD.
34
&&
.FIRE WEATHER...
LITTLE CHANGE IN THE OVERALL PATTERN TODAY WITH A STREAM OF MOISTURE
PERSISTING OVER NEW MEXICO. EXTENSIVE CLOUD COVER FRIDAY HAS THINNED
OUT TODAY...WITH SOMEWHAT BETTER HEATING AND POTENTIAL FOR STORMS
WEST AND CENTRAL...THOUGH FOR THE MOST PART...EXISTING STORMS
APPEAR TO BE STRUGGLING. CELLS WILL MOVE TO THE NORTHEAST AT A GOOD
RATE...AROUND 25 MPH.
WHILE AREAS ALONG AND NEAR THE CONTDVD AS WELL AS THE NORTH CENTRAL
MAY BE FAVORED FOR WETTING RAIN TONIGHT...THE HRRR IS NOW ONBOARD
WITH A LINE OF CONVECTION ALONG THE EAST SLOPES OF THE CENTRAL MT
CHAIN...WHICH PROGRESSES EASTWARD INTO THE PLAINS LATE THIS
AFTERNOON/EARLY THIS EVENING BEFORE DIMINISHING. CURRENT SATELLITE
TRENDS SUPPORT THIS IDEA.
MODELS CONTINUE TO BACK OFF ON THE ANTICIPATED DRYING FOR
SUNDAY/MONDAY. THE MAIN UPPER LOW MOVES EAST OVER THE NRN
ROCKIES...LEAVING A WEAK TROUGH BEHIND AND TO OUR WEST...WHICH KEEPS
AT LEAST SOME MOISTURE FLOWING INTO NM. THE HIGHER POPS WILL FAVOR
LOCALES ALONG AND SOUTH OF INTERSTATE 40. A WEAK WIND SHIFT IS STILL
ON TAP FOR SUNDAY IN THE NORTHEAST BUT IT/S INCONSEQUENTIAL. A
SOMEWHAT STRONGER BOUNDARY WILL IMPACT THE NORTHEAST TUESDAY...AND
YET ANOTHER STRONGER ONE THURSDAY NIGHT/FRIDAY. TIMING ON THE MID TO
LATE WEEK FRONTS HAS BEEN PROBLEMATIC AND EXPECT THERE WILL BE
CHANGES. AREAS ALONG THE CONTDVD AND WWD WILL SEE DEW POINTS DRY OUT
AS THE WEEK PROGRESSES AND WHERE HIGH HAINES IS FORECAST LATE NEXT
WEEK...BUT THE FRONTS WILL REPLENISH LOW LEVEL MOISTURE EAST AND
CENTRAL...WHERE CHANCES FOR WETTING RAIN INCREASE FRIDAY/FRIDAY
NIGHT.
MIN RH VALUES COULD FALL BELOW 15 PERCENT LATE NEXT WEEK FAR
NORTHWEST...AND WILL BE COMBINED WITH FAIR TO POOR OVERNIGHT
RECOVERIES. OVERNIGHT RECOVERIES MAY ONLY BE FAIR FOR SOME OF THE
LOWER TERRAIN CENTRAL AND WEST NEXT TUESDAY AND WEDNESDAY NIGHTS.
HIGHS WILL RUN WITHIN A FEW DEGREES OF AVERAGE FOR MOST OF NEXT
WEEK.
VENT RATES WILL BE MOSTLY GOOD SUNDAY AND MONDAY WITH SOME POCKETS
OF FAIR TO POOR CENTRAL AND WEST. THERE IS SLIGHT IMPROVEMENT
OVERALL TUESDAY AND WEDNESDAY...BUT SOME AREAS OF FAIR TO POOR EAST
WEDNESDAY.
&&
.AVIATION...
18Z TAF CYCLE
UPPER TROF TO THE WEST CONTINUING TO PULL MOISTURE OVR NM WITH
RELATIVELY STRONG SW WINDS ALF AOA MT TOP LEVELS. MTS BECOMING
OCCASIONALLY OBSCURED IN SCT CONVECTION WITH SOME MVFR CIGS/VSBYS
IN STRONGER STORMS. POTENTIAL FOR WIND GUSTS TO 40KT. STORM MOTION
WOULD PERMIT CONVECTION TO MOVE OFF THE CENTRAL MT CHAIN AND INTO
THE ERN PLAINS BUT SHORT TERM MODELS NOT ENTHUSED ABOUT THIS UNTIL
AFT 03Z WHEN HRRR/RAP MOVES A CLUSTER INTO THE NE
HIGHLANDS/PLAINS.
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 56 83 57 85 / 40 5 10 10
DULCE........................... 45 76 45 77 / 60 20 20 10
CUBA............................ 50 75 50 77 / 50 20 20 20
GALLUP.......................... 48 80 50 81 / 40 20 20 20
EL MORRO........................ 48 75 49 77 / 50 30 30 30
GRANTS.......................... 50 79 50 80 / 50 20 20 20
QUEMADO......................... 53 76 54 77 / 40 30 30 30
GLENWOOD........................ 56 80 56 84 / 30 20 20 30
CHAMA........................... 46 73 45 75 / 60 20 20 20
LOS ALAMOS...................... 56 78 58 79 / 50 10 20 20
PECOS........................... 54 77 55 79 / 30 10 10 20
CERRO/QUESTA.................... 51 76 51 77 / 50 10 10 10
RED RIVER....................... 43 68 41 70 / 60 20 20 20
ANGEL FIRE...................... 48 70 47 72 / 50 20 20 20
TAOS............................ 50 78 47 80 / 50 10 10 10
MORA............................ 52 74 51 77 / 30 20 20 20
ESPANOLA........................ 54 83 53 84 / 50 5 10 10
SANTA FE........................ 58 78 58 82 / 50 10 10 10
SANTA FE AIRPORT................ 56 82 56 85 / 50 10 10 10
ALBUQUERQUE FOOTHILLS........... 61 83 62 84 / 50 5 10 20
ALBUQUERQUE HEIGHTS............. 62 84 64 85 / 50 5 10 10
ALBUQUERQUE VALLEY.............. 60 86 61 87 / 50 5 10 10
ALBUQUERQUE WEST MESA........... 61 84 63 85 / 50 5 10 10
LOS LUNAS....................... 58 86 59 87 / 50 5 10 10
RIO RANCHO...................... 62 85 62 86 / 50 5 10 10
SOCORRO......................... 62 86 63 88 / 30 20 20 30
SANDIA PARK/CEDAR CREST......... 56 78 57 82 / 50 10 10 20
TIJERAS......................... 58 81 59 83 / 40 5 10 20
MORIARTY/ESTANCIA............... 52 81 52 84 / 20 10 10 20
CLINES CORNERS.................. 55 79 56 81 / 20 20 20 30
GRAN QUIVIRA.................... 58 81 59 81 / 30 20 20 30
CARRIZOZO....................... 62 84 62 84 / 30 10 20 20
RUIDOSO......................... 58 77 58 78 / 30 30 40 40
CAPULIN......................... 56 81 54 84 / 20 10 10 5
RATON........................... 53 84 52 86 / 30 10 10 10
SPRINGER........................ 54 85 54 87 / 20 10 10 10
LAS VEGAS....................... 54 81 54 83 / 20 10 10 20
CLAYTON......................... 63 89 63 91 / 20 10 10 20
ROY............................. 59 85 58 87 / 20 10 10 20
CONCHAS......................... 66 92 65 93 / 20 10 10 20
SANTA ROSA...................... 64 90 65 91 / 30 10 10 30
TUCUMCARI....................... 66 94 66 95 / 20 10 10 30
CLOVIS.......................... 64 91 64 92 / 10 20 20 30
PORTALES........................ 67 92 65 92 / 10 20 20 30
FORT SUMNER..................... 66 91 66 92 / 20 10 20 30
ROSWELL......................... 68 94 68 94 / 20 20 20 30
PICACHO......................... 62 88 63 88 / 20 20 20 30
ELK............................. 61 82 61 82 / 30 30 40 30
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
34
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
245 PM EDT SAT SEP 5 2015
.SYNOPSIS...
WETTER AND SLIGHTLY COOLER WEATHER IS EXPECTED THE NEXT FEW DAYS
AS HIGH PRESSURE PUSHING FROM THE NORTH COMBINES WITH DEEP AND
MOIST WINDS OFF THE ATLANTIC. A WARMING TREND WITH A DECREASE IN
RAIN CHANCES IS EXPECTED TUESDAY THROUGH MID-WEEK. A COLD FRONT
WILL APPROACH LATE IN THE WEEK AND MAY STALL ALONG THE COAST NEXT
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 245 PM SATURDAY...THE NORTHEAST FLOW CONTINUES ACROSS THE
REGION THIS AFTERNOON AND WILL MAINTAIN THIS PATTERN THROUGH
SUNDAY MORNING. SHALLOW CONVECTION DEVELOPING TO THE NORTH AND
EXPECT SOME ISOLATED ACTIVITY TO MEANDER INTO AND OR DEVELOP
ACROSS OUR AREA THIS AFTERNOON. COVERAGE SHOULD BE LIMITED AS THE
AFFECTS OF A DRY TONGUE AROUND 800MB SLOWLY ABATE. THE LIMITED
CONVECTION IS MOSTLY DIURNALLY DRIVEN AND HAVE DECREASED POPS FOR
THE OVERNIGHT HOURS WHILE NOT REMOVING ENTIRELY. WITH LITTLE TO NO
DECOUPLING EXPECTED...I PEGGED LOWS AT A DEGREE OR TWO ABOVE
GUIDANCE. SHOULD SEE UPPER 60S TO LOWER 70S.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 245 PM SATURDAY...PRIME WEATHER CAPTION THIS PERIOD REMAINS
ELEVATED RAIN CHANCES AND EARLY FALL LIKE DAYTIME TEMPERATURES.
SURFACE HIGH PRESSURE IN WEDGE FASHION WILL PRESS FROM THE NORTH
WHILE THE COLUMN UNDERGOES A DEEP AND MOIST ONSHORE FLOW OFF THE
WESTERN ATLANTIC. H7-H5 VORTICITY DEPICTIONS OVERLAID WITH PCPN
FIELDS SHOW A CYCLONIC UPPER CIRCULATION OFFSHORE OF JAX FLORIDA
ALONG 30N DIRECTING IMPULSES ALOFT INTO COASTAL NE SC AND SE NC
SUNDAY AND MONDAY. TIME HEIGHT PLOTS SHOW LIGHT COLUMN WINDS AND
STEERING FLOW THIS PERIOD WITH HIGH PRECIPITABLE WATERS...WHICH WILL
LEND TO A POTENTIAL FOR LOCALIZED FLOODING BENEATH AND NEAR STOUT
CELLS. DAYTIME HIGHS ARE SETTING UP TO RUN NEAR OR BELOW NORMAL FOR
VERY EARLY SEPTEMBER DUE TO CLOUDS AND RAIN-COOLED AIR. THE WEDGE
WILL LIKELY MEAN LESS RAINFALL INLAND COMPARED TO THE COAST...AND
WPC SUNDAY/MONDAY QPF FORECASTS SHOW UP TO AN INCH NEAR THE COAST
TAPERING TO LESS THAN A QUARTER INCH NEAR AND WEST OF I-95. BECAUSE
OF CLOUDS AND MOISTURE RICH AIR...MINIMUMS MAY RUN A BIT ABOVE
NORMAL EARLY ON MONDAY AND TUESDAY...VERY UPPER 60S INLAND AND LOW
TO MIDDLE 70S NEAR THE COAST.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 245 PM SATURDAY...THERE MAY BE A LITTLE BAGGINESS IN THE
MID LEVEL HEIGHT FIELD TO OUR WEST ON TUESDAY IN ASSOC WITH THE
RETROGRADING AND WEAKENING TROUGH TO SUPPORT SLIGHTLY ELEVATED
POPS. THE SEA BREEZE WILL ALSO MAKE A CONTRIBUTION TO THE COVERAGE
OF CONVECTION WHILE TEMPERATURES HANG CLOSE TO SEASONABLE NORMS.
WESTERLY MID LEVEL FLOW RETURNS ON WEDNESDAY WHILE THE SURFACE
FLOW REMAINS WEAK AS THE BERMUDA HIGH HAS TROUBLE REASSERTING
ITSELF. ISOLATED CONVECTION REMAINS POSSIBLE HOWEVER WITH THE SEA
BREEZE AND ONLY WEAK CAPPING. MUCH OF THIS WILL HOLD TRUE ON
THURSDAY THOUGH A PIEDMONT TROUGH WILL CREATE SOME LOW LEVEL
STEERING FOR THE SEA BREEZE IN ADDITION TO YIELDING ITS OWN
ISOLATED CONVECTION. MOISTURE SHOULD DEEPEN ON FRIDAY AS MID LEVEL
FLOW BACKS IN RESPONSE TO DEEP TROUGH DIGGING INTO THE GREAT
LAKES. THIS UPPER SYSTEM DRIVES WHAT MAY BE A STRONG COLD FRONT
INTO THE REGION COME SATURDAY.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 18Z...HIGH PRESSURE WILL CONTINUE TO RIDGE INTO THE REGION
THROUGH THE AFTERNOON HOURS WITH ONLY A SLIGHT CHANCE FOR
SHOWERS...MAINLY INLAND. THE LATEST HRRR MODEL CONFIRMS THIS WITH
ONLY ISOLATED CONVECTION THROUGH THE AFTERNOON HOURS ALONG THE
RESULTANT AND POINTS WEST. LIGHT NORTHEAST FLOW WILL CONTINUE THIS
EVENING. THERE IS A MODERATE RISK FOR MVFR/IFR CONDITIONS TOWARD
MORNING WITH THE WEDGE IN PLACE. MAINLY A MVFR CEILING FOR SUNDAY
WITH SCATTERED CONVECTION POSSIBLE.
EXTENDED OUTLOOK...PREDOMINATELY VFR WITH BRIEF MVFR AND POSSIBLY
IFR...IN MORNING FOG...AND ISOLATED/SCATTERED AFTERNOON EARLY
EVENING SHOWERS AND THUNDERSTORMS THROUGH THE EXTENDED.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 245 PM SATURDAY...WINDS FAIRLY STEADY AT JUST UNDER 15
KNOTS AT JMPN7 WITH SLIGHTLY HIGHER VALUES FOR 41013 AT THIS HOUR.
12 UTC GUIDANCE SHOWS A BRIEF SURGE MOVING THROUGH AT 925MB WHICH
IS KICKING UP WINDS A BIT MORE THAN EXPECTED. A BRIEF 15-20 KNOT
RANGE SHOULD COVER THE NC ZONES THIS AFTERNOON WHILE ALL WATERS
SETTLE INTO A 10-15 KNOT RANGE THIS EVENING AND OVERNIGHT. THE
SWAN MODEL HAS INITIALIZED SEAS WELL WITH FOUR FOOTERS ACROSS THE
OUTER WATERS. THE TREND ALONG WITH THE WINDS SHOULD BE DOWN THIS
EVENING AND OVERNIGHT SETTLING INTO A 2-3 FOOT RANGE.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 245 PM SATURDAY...10-15 KT NE-ENE WINDS WILL KEEP SEAS A
MODERATELY BUMPY 3 FOOT MOST AREAS...EXCEPT 2 FEET OR LESS IN
THE PROTECTED LOCATIONS OFF THE BRUNSWICK COAST FROM NE WIND.
BY TUESDAY WINDS WILL VEER TO E-SE AS HIGH PRESSURE WEAKENS OVER
THE AREA. SCATTERED SHOWERS AND ISOLATED TSTMS CAN BE EXPECTED
OVER THE WATERS THIS PERIOD AS SEVERAL WEAK DISTURBANCES ALOFT
MOVE ONSHORE SUNDAY AND MONDAY. VSBYS COULD BE LIMITED AT TIMES
IN RAIN TO 2 NM. SEAS 3 FEET IN ESE WAVES 2 FEET EVERY 9 SECONDS
AND NE-E WAVES 1-2 FEET EVERY 4-5 SECONDS.
LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 245 PM SATURDAY...THE GRADIENT WILL BE POORLY DEFINED ON
TUESDAY LEADING TO A LIGHT AND SOMEWHAT VARIABLE WIND AT LEAST
INITIALLY. AS THE DAY WEARS ON A RATHER SEASONABLY NORMAL SOUTHERLY
COMPONENT WILL BECOME ESTABLISHED EVEN AS SPEEDS REMAIN BELOW 10 KT.
AN EASTERLY SWELL COMPONENT OF 10-11 SECONDS WILL COMBINE WITH THE
MINIMAL WIND WAVES FOR A 2 FT SEAS FORECAST. SOUTH TO SOUTHWEST FLOW
MAY INCREASE 5 FT ON WEDNESDAY SEEMINGLY DUE TO SLIGHTLY HIGHER
WINDS ALOFT RATHER THAN ANY REAL INCREASE OR CHANGE IN THE SURFACE
PRESSURE PATTERN. A PIEDMONT TROUGH ON THE OTHER HAND WILL KEEP US
LOCKED INTO A 10-15KT SOUTHWESTERLY FLOW. EACH DAY WILL SEE A
NEARSHORE SEABREEZE VEER IN WIND DIRECTION.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MJC
NEAR TERM...SHK
SHORT TERM...MJC
LONG TERM...MBB
AVIATION...DL/SHK
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
122 PM EDT SAT SEP 5 2015
.SYNOPSIS...
HIGH PRESSURE WILL RIDGE DOWN FROM NEW ENGLAND TODAY BRINGING
COOLER TEMPERATURES. THIS HIGH PRESSURE WILL PERSIST INTO EARLY
NEXT WEEK CONTINUING SOMEWHAT BELOW NORMAL TEMPERATURES...BUT WITH
INCREASING CHANCES FOR SHOWERS. A RETURN TO MORE TYPICAL LATE
SUMMER WEATHER WILL DEVELOP TUESDAY AND PERSIST THROUGH THE END OF
THE WEEK. A COLD FRONT WILL APPROACH BY NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 125 PM SATURDAY...THE NORTHEAST FLOW CONTINUES ACROSS THE REGION
THIS AFTERNOON AND WILL MAINTAIN THIS PATTERN THROUGH SUNDAY
MORNING. SHALLOW CONVECTION DEVELOPING TO THE NORTH AND EXPECT
SOME ISOLATED ACTIVITY TO MEANDER INTO AND OR DEVELOP ACROSS OUR
AREA THIS AFTERNOON. COVERAGE SHOULD BE LIMITED AS THE AFFECTS OF
A DRY TONGUE AROUND 800MB SLOWLY ABATE. THE LIMITED CONVECTION IS
MOSTLY DIURANNALY DRIVEN AND HAVE DECREASED POPS FOR THE OVERNIGHT
HOURS WHILE NOT REMOVING ENTIRELY. WITH LITTLE TO NO DECOUPLING
EXPECTED...I PEGGED LOWS AT A DEGREE OR TWO ABOVE GUIDANCE. SHOULD
SEE UPPER 60S TO LOWER 70S.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SATURDAY...UPPER TROUGH WILL CLOSE OFF AND BE FORCED TO
RETROGRADE FROM THE WESTERN ATLANTIC OCEAN BACK ACROSS THE SOUTHEAST
THIS PERIOD AS LARGE RIDGING BLOCKS ITS PROGRESSION TO THE NORTH OR
EAST. BENEATH THIS FEATURE...A SURFACE TROUGH WILL ALSO BACK IN FROM
THE ATLANTIC AND INTO THE CAROLINAS SUNDAY INTO MONDAY...ALONG WITH
HIGHER PRECIPITABLE WATERS FROM REMNANT TROPICAL MOISTURE POOLED
FROM EX-TROPICAL STORM ERIKA. ALL OF THESE FEATURES TOGETHER WILL
CREATE A GOOD CHANCE FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY
DURING THE AFTNS WHEN HEATING OF THE DAY WILL HELP TRIGGER
CONVECTION ALONG THE SURFACE TROUGH. HOWEVER...AT LEAST SCHC POP
WILL BE CARRIED EVEN AT NIGHT DUE TO HIGH COLUMN MOISTURE...THE
SURFACE FEATURE...AND RELATIVELY STEEPER LAPSE RATES THANKS TO THE
500MB TROUGH OVERHEAD.
TEMPS BOTH DAYS WILL LIKELY FEATURE LOW DIURNAL RANGES AS CLOUD
COVER AND PRECIP KEEPS MINS ABOVE NORMAL AND HIGHS BELOW. EXPECT
LOWS EACH NIGHT TO DROP TO 68-72...WARMEST AT THE COAST...WITH
HIGHS IN THE LOW 80S AT THE COAST...MID 80S WELL INLAND.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 300 AM SATURDAY...UPPER TROUGH PLAGUING THE SOUTHEAST THE
SEVERAL DAYS LEADING UP TO THIS PERIOD WILL SLOWLY FILL AND
DISSIPATE BY MID-WEEK AS RIDGING DEVELOPS NEAR FLORIDA AND EXPANDS
TO THE NORTH. WHILE OVERALL THICKNESS INCREASE WILL BE
MARGINAL...THE EROSION OF THE SURFACE TROUGH ASSOCIATED WITH THE
BUILDING HEIGHTS COMBINED WITH BERMUDA-TYPE RIDGING WILL BRING DRIER
AND WARMER CONDITIONS MUCH OF NEXT WEEK. TUESDAY MAY STILL FEATURE
ABOVE-CLIMO PRECIP CHANCES AS IT IS THE TRANSITION DAY...BUT WED-FRI
WILL BE MORE SUMMER-LIKE WITH TYPICAL DIURNAL CONVECTIVE CHANCES AND
TEMPS SEVERAL DEGREES ABOVE CLIMO FOR BOTH HIGHS AND LOWS. A COLD
FRONT WILL APPROACH LATE IN THE PERIOD BUT FOR NOW WILL KEEP IT JUST
NW OF THE AREA UNTIL THE WEEKEND.
&&
.AVIATION /17Z SATURDAY THROUGH WEDNESDAY/...
AS OF 18Z...HIGH PRESSURE WILL CONTINUE TO RIDGE INTO THE REGION
THROUGH THE AFTERNOON HOURS WITH ONLY A SLIGHT CHANCE FOR
SHOWERS...MAINLY INLAND. THE LATEST HRRR MODEL CONFIRMS THIS WITH
ONLY ISOLATED CONVECTION THROUGH THE AFTERNOON HOURS ALONG THE
RESULTANT AND POINTS WEST. LIGHT NORTHEAST FLOW WILL CONTINUE THIS
EVENING. THERE IS A MODERATE RISK FOR MVFR/IFR CONDITIONS TOWARD
MORNING WITH THE WEDGE IN PLACE. MAINLY A MVFR CEILING FOR SUNDAY
WITH SCATTERED CONVECTION POSSIBLE.
EXTENDED OUTLOOK...PREDOMINATELY VFR WITH BRIEF MVFR AND POSSIBLY
IFR...IN MORNING FOG...AND ISOLATED/SCATTERED AFTERNOON EARLY
EVENING SHOWERS AND THUNDERSTORMS THROUGH THE EXTENDED.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 125 PM SATURDAY...WINDS FAIRLY STEADY AT JUST UNDER 15 KNOTS AT
JMPN7 WITH SLIGHTLY HIGHER VALUES FOR 41013 AT THIS HOUR. 12 UTC
GUIDANCE SHOWS A BRIEF SURGE MOVING THROUGH AT 925MB WHICH IS
KICKING UP WINDS A BIT MORE THAN EXPECTED. A BRIEF 15-20 KNOT RANGE
SHOULD COVER THE NC ZONES THIS AFTERNOON WHILE ALL WATERS SETTLE
INTO A 10-15 KNOT RANGE THIS EVENING AND OVERNIGHT. THE SWAN MODEL
HAS INITIALIZED SEAS WELL WITH FOUR FOOTERS ACROSS TEH OUTER WATERS.
THE TREND ALONG WITH THE WINDS SHOULD BE DOWN THIS EVENING AND
OVERNIGHT SETTLING INTO A 2-3 FOOT RANGE.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM FRIDAY...SURFACE RIDGE OF HIGH PRESSURE WILL BUILD DOWN
THE COAST THROUGH THE SHORT TERM...WHILE A COASTAL TROUGH PUSHES
SLOWLY INLAND BENEATH A MID-LEVEL TROUGH. THIS WILL MAINTAIN NE
WINDS SUNDAY AND MUCH OF MONDAY...WITH SLIGHT VEERING TO MORE
EASTERLY WINDS LATE MONDAY AS THE SURFACE TROUGH PUSHES INLAND.
HIGHEST SPEEDS THIS PERIOD WILL BE SUNDAY WHEN THE RIDGE IS
STRONGEST AND THE GRADIENT IS PINCHED...AS WINDS REACH 15-20 KTS
BEFORE FALLING BACK TO 10-15 KTS BY MONDAY...AND THEN BELOW 10 KTS
MONDAY NIGHT. THE SEA SPECTRUM WILL BE DOMINATED BY A 5-6 SEC NE
WIND WAVE WHICH WILL EASE AND LENGTHEN INTO MONDAY...CREATING 3-4 FT
SEAS SUNDAY...DROPPING TO 1-3 FT ON MONDAY.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 300 AM SATURDAY...HIGH PRESSURE EXPANDING OFF THE FLORIDA
COAST WILL DRIVE A RETURN TO MORE TYPICAL SUMMERTIME CONDITIONS
THROUGH MID WEEK. TUESDAY WILL BE THE TRANSITION DAY AS WINDS VEER
BETWEEN E/NE EARLY TO SOUTH LATE...AND THEN EVEN FURTHER TO SW ON
WEDNESDAY THANKS TO RETURN FLOW DEVELOPING AROUND THE SURFACE HIGH.
ALTHOUGH THIS VARIETY OF WIND DIRECTION MAY CAUSE A CONFUSED
SPECTRUM TUESDAY...WIND SPEEDS WILL BE LIGHT AROUND 10 KTS...SO WAVE
AMPLITUDES WILL BE 1-3 FT TUESDAY. AS THE SW WINDS BECOME DOMINANT
WEDNESDAY...SEAS WILL REMAIN 1-3 FT BUT A GROUND SWELL WILL BEGIN TO
INCREASE IN AMPLITUDE WITHIN THE SPECTRUM.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SHK
NEAR TERM...SHK
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...DL
AREA FORECAST DISCUSSION
NWS BISMARCK ND
541 PM CDT SAT SEP 5 2015
.UPDATE...
ISSUED AT 534 PM CDT SAT SEP 5 2015
UPDATE TO CLEAN UP POPS A BIT ACROSS CENTRAL NORTH DAKOTA. SHOWERS
AND SCATTERED THUNDERSTORMS CONTINUE TO LIFT NORTHEAST ACROSS
CENTRAL NORTH DAKOTA. THE WEST AND SOUTH CENTRAL HAVE CLEARED OUT
AND HAVE LOWERED POPS...AT LEAST FOR A WHILE. STILL REMAINS VERY
UNSTABLE OUT WEST AND ANOTHER ROUND OF CONVECTION IS EXPECTED TO
DEVELOP OVER SOUTHEAST MONTANA LATE THIS AFTERNOON OR EARLY
EVENING AND TRACK INTO WESTERN NORTH DAKOTA. WILL CONTINUE TO
MONITOR FOR POSSIBLE SEVERE...BUT FOR THE TIME BEING A LITTLE
BREAK IN THE CONVECTION ACROSS THE WEST.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 230 PM CDT SAT SEP 5 2015
THUNDERSTORM POTENTIAL THIS AFTERNOON THROUGH TONIGHT HIGHLIGHTS
THE SHORT TERM FORECAST.
AS OF 1930 UTC...TWO CONVECTIVE COMPLEXES ACROSS CENTRAL NORTH
DAKOTA IN ASSOCIATION WITH A SHORTWAVE ACROSS NORTH CENTRAL SOUTH
DAKOTA...AND A THIRD COMPLEX ACROSS NORTHWEST NORTH DAKOTA ON THE
APEX OF THE LOW LEVEL JET WHERE WARM AIR ADVECTION IS BEING
MAXIMIZED...WILL CONTINUE TO PROPAGATE NORTHEAST THROUGH THE
AFTERNOON. LOCALLY HEAVY RAINFALL IS THE PRIMARY THREAT WITH THESE
PRECIPITATION AREAS. SPC HAS UPGRADED THE SOUTHWEST TO A SLIGHT
RISK FOR SEVERE STORMS THIS AFTERNOON AND EVENING. WHILE
CONVECTIVE COVERAGE WILL BE MORE SCATTERED...THE AREA IS BEGINNING
TO CLEAR OUT WITH 60S F DEWPOINTS IN PLACE UNDER FAVORABLE
SOUTHWEST FLOW ALOFT.
FOR LATE THIS EVENING AND INTO THE OVERNIGHT...THE 14-18 UTC
OPERATIONAL AND EXPERIMENTAL HRRR ITERATIONS...12 UTC NAM NEST AND
12 UTC WRF-ARW/NMM RUNS ALL SHOW A CONVECTIVE COMPLEX PROPAGATING
OUT OF MONTANA INTO WESTERN NORTH DAKOTA ASSOCIATED WITH STRONG
DIFFLUENCE AHEAD OF THE DEEPENING UPPER LEVEL LOW ACROSS SOUTHEAST
ALBERTA. CERTAINLY COULD NOT RULE OUT A STRONG TO SEVERE STORM
WITH AROUND 1000 J/KG OF ELEVATED CAPE AND AROUND 30-40KTS OF DEEP
LAYER SHEAR. IN REGARDS TO FOG FOR TONIGHT...A SIMILAR SETUP IS
IN PLACE FOR TONIGHT AS IT WAS LAST NIGHT...SO ADDED FOG TO MOST
OF THE AREA. THE DRY SLOT OF THE AFOREMENTIONED LOW WILL OVERTAKE
WESTERN AND CENTRAL NORTH DAKOTA ON SUNDAY...WITH A
COOLER...BREEZY BUT DRIER SUNDAY AHEAD.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 534 PM CDT SAT SEP 5 2015
IFR STRATUS AND PATCHY FOG FROM THIS MORNING HAS IMPROVED THIS
AFTERNOON. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ACROSS
THE NORTH CENTRAL AND EAST WILL CONTINUE...WITH ANOTHER ROUND
ENTERING WESTERN NORTH DAKOTA TONIGHT. FOG AND STRATUS IS EXPECTED
ONCE AGAIN LATE TONIGHT INTO SUNDAY MORNING ACROSS MUCH OF THE
AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 230 PM CDT SAT SEP 5 2015
IFR STRATUS AND PATCHY FOG FROM THIS MORNING WILL SLOWLY IMPROVE
THIS AFTERNOON. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS
ACROSS THE AREA THIS AFTERNOON WILL CONTINUE...WITH ANOTHER ROUND
ENTERING WESTERN NORTH DAKOTA TONIGHT. FOG AND STRATUS IS
EXPECTED ONCE AGAIN LATE TONIGHT INTO SUNDAY MORNING ACROSS MUCH
OF THE AREA.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
244 PM CDT SAT SEP 5 2015
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 230 PM CDT SAT SEP 5 2015
THUNDERSTORM POTENTIAL THIS AFTERNOON THROUGH TONIGHT HIGHLIGHTS
THE SHORT TERM FORECAST.
AS OF 1930 UTC...TWO CONVECTIVE COMPLEXES ACROSS CENTRAL NORTH
DAKOTA IN ASSOCIATION WITH A SHORTWAVE ACROSS NORTH CENTRAL SOUTH
DAKOTA...AND A THIRD COMPLEX ACROSS NORTHWEST NORTH DAKOTA ON THE
APEX OF THE LOW LEVEL JET WHERE WARM AIR ADVECTION IS BEING
MAXIMIZED...WILL CONTINUE TO PROPAGATE NORTHEAST THROUGH THE
AFTERNOON. LOCALLY HEAVY RAINFALL IS THE PRIMARY THREAT WITH THESE
PRECIPITATION AREAS. SPC HAS UPGRADED THE SOUTHWEST TO A SLIGHT
RISK FOR SEVERE STORMS THIS AFTERNOON AND EVENING. WHILE
CONVECTIVE COVERAGE WILL BE MORE SCATTERED...THE AREA IS BEGINNING
TO CLEAR OUT WITH 60S F DEWPOINTS IN PLACE UNDER FAVORABLE
SOUTHWEST FLOW ALOFT.
FOR LATE THIS EVENING AND INTO THE OVERNIGHT...THE 14-18 UTC
OPERATIONAL AND EXPERIMENTAL HRRR ITERATIONS...12 UTC NAM NEST AND
12 UTC WRF-ARW/NMM RUNS ALL SHOW A CONVECTIVE COMPLEX PROPAGATING
OUT OF MONTANA INTO WESTERN NORTH DAKOTA ASSOCIATED WITH STRONG
DIFFLUENCE AHEAD OF THE DEEPENING UPPER LEVEL LOW ACROSS SOUTHEAST
ALBERTA. CERTAINLY COULD NOT RULE OUT A STRONG TO SEVERE STORM
WITH AROUND 1000 J/KG OF ELEVATED CAPE AND AROUND 30-40KTS OF DEEP
LAYER SHEAR. IN REGARDS TO FOG FOR TONIGHT...A SIMILAR SETUP IS
IN PLACE FOR TONIGHT AS IT WAS LAST NIGHT...SO ADDED FOG TO MOST
OF THE AREA. THE DRY SLOT OF THE AFOREMENTIONED LOW WILL OVERTAKE
WESTERN AND CENTRAL NORTH DAKOTA ON SUNDAY...WITH A
COOLER...BREEZY BUT DRIER SUNDAY AHEAD.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 230 PM CDT SAT SEP 5 2015
THE LONG TERM APPEARS QUIET AND COOL.
WESTERLY FLOW ALOFT WILL BRING MILD TEMPERATURES INTO THE REGION
THROUGH NEXT WEEK. TEMPERATURES WILL HOVER NEAR NORMAL WITH
READINGS IN THE UPPER 60S AND 70S DURING THE DAY AND 40S AT NIGHT.
WESTERLY FLOW ALOFT SHOULD LIMIT ANY MAJOR STORM SYSTEMS FROM
IMPACTING THE REGION THROUGH THE NEXT WEEK. HOWEVER...SEVERAL
QUICK MOVING SHORTWAVE TROUGHS MAY MOVE THROUGH AND BRING A SLIGHT
CHANCE FOR SOME SHOWERS AND THUNDERSTORMS MIDWEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 230 PM CDT SAT SEP 5 2015
IFR STRATUS AND PATCHY FOG FROM THIS MORNING WILL SLOWLY IMPROVE
THIS AFTERNOON. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS
ACROSS THE AREA THIS AFTERNOON WILL CONTINUE...WITH ANOTHER ROUND
ENTERING WESTERN NORTH DAKOTA TONIGHT. FOG AND STRATUS IS
EXPECTED ONCE AGAIN LATE TONIGHT INTO SUNDAY MORNING ACROSS MUCH
OF THE AREA.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AYD
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
118 PM CDT SAT SEP 5 2015
.UPDATE...
ISSUED AT 107 PM CDT SAT SEP 5 2015
AS OF 18 UTC...TWO CONVECTIVE COMPLEXES ACROSS THE CENTRAL DAKOTAS
IN ASSOCIATION WITH A SHORTWAVE ACROSS NORTH CENTRAL SOUTH
DAKOTA...AND A THIRD COMPLEX ACROSS NORTHWEST NORTH DAKOTA ON THE
APEX OF THE LOW LEVEL JET WHERE WARM AIR ADVECTION IS BEING
MAXIMIZED...WILL CONTINUE TO PROPAGATE NORTHEAST THROUGH THE
AFTERNOON. LOCALLY HEAVY RAINFALL IS THE PRIMARY THREAT WITH THESE
PRECIPITATION AREAS. SPC HAS UPGRADED THE SOUTHWEST TO A SLIGHT
RISK FOR SEVERE STORMS THIS AFTERNOON AND EVENING. WHILE
CONVECTIVE COVERAGE WILL BE MORE SCATTERED...THE AREA IS
BEGINNING TO CLEAR OUT WITH 60S F DEWPOINTS IN PLACE UNDER
FAVORABLE SOUTHWEST FLOW ALOFT.
UPDATE ISSUED AT 951 AM CDT SAT SEP 5 2015
NO SIGNIFICANT CHANGES WITH THIS FORECAST UPDATE. EXPECT A PEAK IN
PRECIPITATION COVERAGE BETWEEN NOW AND MID DAY...DECREASING
THEREAFTER THROUGH THE LATE AFTERNOON AND EARLY EVENING AS THE
SHORTWAVE ACROSS CENTRAL SOUTH DAKOTA THIS MORNING PROPAGATES INTO
NORTHEAST NORTH DAKOTA. SPC HAS MAINTAINED OUR AREA IN A MARGINAL
RISK FOR SEVERE STORMS. THIS IS PLAUSIBLE...YET DEPENDENT ON
HEATING IN LIGHT OF THE WIDESPREAD CLOUD COVER THIS MORNING.
SHOULD CLOUD COVER THIN A BIT...WHICH IS MOST LIKELY ACROSS THE
SOUTHWEST... 60S F DEWPOINTS IN PLACE UNDER SOUTHWEST FLOW ALOFT
WOULD SUPPORT THE POTENTIAL FOR A SEVERE STORM OR TWO.
FOR LATE THIS EVENING AND INTO THE OVERNIGHT...THE 10-13 UTC
OPERATIONAL AND EXPERIMENTAL HRRR ITERATIONS...12 UTC NAM NEST AND
00 UTC WRF-ARW/NMM RUNS ALL SHOW A CONVECTIVE COMPLEX PROPAGATING
OUT OF MONTANA INTO WESTERN NORTH DAKOTA ASSOCIATED WITH STRONG
DIFFLUENCE AHEAD OF THE DEEPENING UPPER LEVEL LOW ACROSS
SOUTHEAST ALBERTA. CERTAINLY COULD NOT RULE OUT A STRONG TO SEVERE
STORM WITH AROUND 1000 J/KG OF ELEVATED CAPE AND AROUND 30-40KTS
OF DEEP LAYER SHEAR.
UPDATE ISSUED AT 603 AM CDT SAT SEP 5 2015
FOR MORNING UPDATE HAVE ADJUSTED POPS A BIT TOWARDS CURRENT
TRENDS WHICH SEEM TO BE PICKED UP RATHER WELL BY THE HRRR MODEL.
HEAVIER PRECIPITATION WILL CONTINUE TO PUSH NORTH TOWARDS
CANADA...BUT BEHIND IT A LINE OF SHOWERS/THUNDERSTORMS STRETCHING
SOUTHWARD WILL SHIFT EASTWARD AND FILL IN A BIT. HAVE ALSO BUMPED
UP FOG COVERAGE A BIT OVER SOUTH CENTRAL NORTH DAKOTA INTO THE
JAMES RIVER VALLEY WHERE VISIBILITIES HAVE DIPPED DOWN TO AROUND
1/4 MILE AT TIMES. THE COVERAGE OF THIS IS NOT WIDESPREAD SO WILL
REFRAIN FROM ISSUING AN ADVISORY...BUT WILL COVER WITH A SPECIAL
WEATHER STATEMENT FOR EARLY THIS MORNING.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY AFTERNOON)
ISSUED AT 410 AM CDT SAT SEP 5 2015
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD CONTINUES TO BE
SHOWER AND THUNDERSTORM POTENTIAL.
CURRENTLY...STRONG EMBEDDED S/WV LIFTING NORTH-NORTHEAST INTO
WESTERN NORTH DAKOTA RESPONSIBLE FOR ROBUST CONVECTION NOW MOVING
INTO MY NORTHWEST AND NORTH CENTRAL. THIS ACTIVITY WILL QUICKLY
MOVE NORTH OF THE CANADIAN BORDER BY 12Z. CONTINUED CHANCES FOR
SHOWERS AND THUNDERSTORMS THIS MORNING WEST AHEAD OF AN UPPER
LEVEL JET AND NEAR A QUASI-STATIONARY FRONTAL BOUNDARY.
ONCE AGAIN A WIDE VARIETY OF SOLUTIONS WITH FORECAST QPF FOR
TODAY. HOWEVER...THERE APPEARS TO BE A DECENT ENOUGH CONSENSUS TO
KEEP HIGH POPS CENTRAL INTO EAST THIS MORNING INTO THE AFTERNOON
WITH ANOTHER STRONG EMBEDDED WAVE LIFTING NORTH-NORTHEAST ACROSS
CENTRAL SOUTH DAKOTA THIS MORNING AND INTO EASTERN NORTH DAKOTA
THIS AFTERNOON. FORCING WILL BE ENHANCED AS THE NOSE OF A STRONG
UPPER LEVEL JET PUSHES NORTHEAST INTO THE DAKOTAS. FOCUSED HIGHER
POPS ALONG THE AFOREMENTIONED QUASI-STATIONARY BOUNDARY. STRONG
MOISTURE FEED CONTINUES FROM TROPICAL STORM KEVIN...SO HEAVY
RAINERS WILL ONCE AGAIN BE POSSIBLE TODAY. IN ADDITION...A FEW
STRONGER STORMS ONCE AGAIN POSSIBLE 1-1.5K MUCAPE AND AROUND 35KTS
OF WIND SHEAR.
THE UPPER JET WILL FORCE THE STATIONARY SFC LOW FINALLY OFF TO
OUR NORTH AND EAST THIS EVENING INTO THE OVERNIGHT ALLOWING FOR A
DRY WESTERLY FLOW TO DEVELOP INTO THE WESTERN DAKOTAS AFTER 00Z.
LINGERING PRECIPITATION POSSIBLE EAST WITH BETTER CHANCES
NORTHWEST AND NORTH CENTRAL TONIGHT NEAR THE TRACK OF THE BASE OF
THE WEST COAST TROUGH LIFTING NORTHEAST ACROSS MONTANA AND INTO
SASKATCHEWAN. ALL AREAS SHOULD BE DRY BY SUNDAY AFTERNOON AS THE
DRY WESTERLY FLOW CONTINUES TO EXPAND ACROSS THE NORTHERN PLAINS.
BREEZY BUT PLEASANT FOR SUNDAY AS SFC DEWPOINT TEMPERATURES FALL
FROM THE 60S AND LOW 70S WE HAVE SEEN THE PAST COUPLE OF DAYS
DOWN INTO THE 40S AND LOW 50S BY SUNDAY AFTERNOON.
.LONG TERM...(SUNDAY EVENING THROUGH FRIDAY)
ISSUED AT 345 AM CDT SAT SEP 5 2015
QUIET WEATHER IS EXPECTED SUNDAY NIGHT AS BROAD AREA OF
PRECIPITATION CONTINUES TO LIFT TO THE NORTHEAST. ON
MONDAY...AREA WILL BE UNDER COOL BROAD CYCLONIC FLOW. THIS MAY
LEAD TO SOME SHOWERS DEVELOPING...AND POSSIBLY A WEAK THUNDERSTORM
OR TWO...OVER SOUTH CENTRAL NORTH DAKOTA INTO THE JAMES RIVER
VALLEY. QUIET WEATHER RETURNS IN THE EVENING WITH LOSS OF DAYTIME
HEATING. QUIET WEATHER IS EXPECTED ON MONDAY WITH WEAK RIDGE
PASSING OVER...THOUGH TEMPERATURES WILL REMAIN COOL. THROUGH THE
REMAINDER OF THE WEEK WILL HAVE OCCASIONAL LOW CHANCES FOR
PRECIPITATION AS A VARIETY OF WEAK DISTURBANCES PASS THROUGH.
TEMPERATURES WILL GRADUALLY WARM TOWARDS THE END OF THE WEEK WITH
RIDGING OVER THE WESTERN CONUS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 107 PM CDT SAT SEP 5 2015
IFR STRATUS AND PATCHY FOG FROM THIS MORNING WILL SLOWLY IMPROVE
THIS AFTERNOON. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS
ACROSS THE AREA THIS AFTERNOON WILL CONTINUE...WITH ANOTHER ROUND
ENTERING WESTERN NORTH DAKOTA TONIGHT. FOG AND STRATUS IS
EXPECTED ONCE AGAIN LATE TONIGHT INTO SUNDAY MORNING ACROSS MUCH
OF THE AREA.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...NH
LONG TERM...JJS
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS PORTLAND OR
257 PM PDT SAT SEP 5 2015
.SYNOPSIS...AN UPPER LEVEL TROUGH WILL MOVE EAST OF THE CASCADES
TODAY WITH SHOWERS OVER THE CASCADES GRADUALLY ENDING. A WEAK FRONT
WILL BRING SOME LIGHT RAIN TO THE COAST OVERNIGHT SATURDAY...AND
POSSIBLY NORTHERN INLAND AREAS SUNDAY AFTERNOON. DRY WEATHER IS
EXPECTED FOR LABOR DAY. ANOTHER WEAK FRONT MAY BRING LIGHT RAIN TO
AREAS NORTH OF THE COLUMBIA RIVER TUESDAY MORNING. AN UPPER LEVEL
RIDGE SHOULD KEEP THE NEXT APPROACHING DISTURBANCES NORTH OF THE
AREA THEREAFTER WITH WARMING TEMPERATURES THROUGH THE REMAINDER OF
THE WEEK.
&&
.SHORT TERM...THE UPPER TROUGH HAS SHIFTED WELL EAST OF THE CASCADES
TODAY WITH THE NEXT DISTURBANCE PRESENTLY LOCATED OFF THE NORTHERN
END OF VANCOUVER ISLAND. AS OF 2 PM PDT...NWS DOPPLER RADAR DEPICTS
WIDESPREAD SHOWERS ACROSS THE NORTHERN PORTION OF THE FORECAST
AREA...NORTH OF A ROUGHLY PACIFIC CITY TO SALEM LINE. SURFACE
ANALYSIS REVEALS A WEAK WARM FRONT ALIGNED NORTH TO SOUTH NEAR THE
COAST...THE LIKELY CAUSE FOR SOME WEAK FORCED ASCENT THAT IS TAPPING
INTO WEAK INSTABILITY TO CREATE SCATTERED SHOWERS ACROSS MUCH OF THE
NORTHERN PORTION OF THE FORECAST AREA THIS AFTERNOON. KRTX DOPPLER
RADAR DEPICTS THESE SHOWERS REMAINING GENERALLY NORTH OF A PACIFIC
CITY TO SALEM LINE. EXPECT THESE SHOWERS TO CONTINUE INTO THIS
EVENING BUT TAPER OFF FROM WEST TO EAST.
MEANWHILE...LATEST VISIBLE SATELLITE IMAGERY AND OBSERVATIONS DEPICT
THE MAIN SURFACE FRONT APPROACHING THE NORTHERN SIDE OF VANCOUVER
ISLAND AT THIS TIME. SURFACE ANALYSIS REVEALS A HIGHLY KINKED SURFACE
COLD FRONT...LENDING SOME ADDITIONAL UNCERTAINTY IN TIMING THE
PROGRESS OF THE SYSTEM. ADDITIONALLY...A FEW OF THE HIGH-RES MODELS
SUGGEST A FASTER PROGRESSION...WHILE THE 12Z SUITE OF LARGER SCALE
MODELS REMAIN FAIRLY IN LINE WITH PREVIOUS RUNS. NUDGED THE TIMING OF
INCREASED POPS A FEW HOURS EARLIER IN A BIT OF COMPROMISE. HAVE A
HARD TIME COMING ALL THE WAY UP TO THE HRRR TIMING GIVEN SOME
DISCREPANCIES IN THE BETWEEN MOISTURE AND WIND FIELDS.
NONETHELESS...INCREASING CLOUDS WILL MOVE INTO INTO THE NORTH COAST
TONIGHT AND PUSH INLAND. EXPECT MORE PROMINENT RAIN INTO THE COAST BY
AROUND 11 PM AND INLAND SUNDAY MORNING. STILL THINK HIGHEST QPF WILL
BE ALONG THE NORTHERN COAST AND COAST RANGE...BUT LATEST MODEL TRENDS
GIVE A LITTLE REASON TO SUGGEST SOME WIDESPREAD MEASURABLE RAIN IN
THE NORTHERN INTERIOR TOO...PARTICULARLY WITH A SWATH OF MOISTURE
EVIDENT IN LATEST WATER VAPOR IMAGERY WITH PW VALUES IN EXCESS OF ONE
INCH. THIS REMAINS THE LOWEST CONFIDENCE OF THE FORECAST
PERIOD...ALONG WITH THE PRECISE TIMING OF THE ARRIVAL OF THE FRONT.
ASSOCIATED CLOUDINESS SHOULD KEEP TEMPERATURES AROUND 70 DEGREES
INLAND FROM SALEM NORTHWARD...BUT FEWER CLOUDS SOUTH COULD LET EUGENE
WARM INTO THE MID 70S.
SHORTWAVE TROUGH PASSES THROUGH THE AREA WITH HEIGHTS RISING SUNDAY
NIGHT INTO MONDAY. THIS WILL BRING DRY WEATHER AND SLIGHTLY WARMER
TEMPERATURES FOR THE LABOR DAY HOLIDAY. ANOTHER DISTURBANCE MOVES
INTO SOUTHERN B.C. ON TUESDAY BUT WITH A STRENGTHENING UPPER RIDGE
SUSPECT THE PRIMARY IMPACT WILL BE SOME ADDITIONAL CLOUDS MOST RAIN
REMAINS NORTH OF THE AREA EXCEPT FOR PERHAPS SOME LIGHT DRIZZLE
NORTHER OF THE COLUMBIA RIVER LATER TUE AFTERNOON. CULLEN
.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY. UPPER LEVEL RIDGE KEEPS
THE STORM TRACK NORTH OF OUR AREA THROUGH AT LEAST SATURDAY. THIS
WILL KEEP OUR AREA DRY...AND WILL WARM INLAND TEMPERATURES INTO THE
LOW 80S BY WEDNESDAY. WINDS SHIFT MORE OFFSHORE LATE IN THE
WEEK...WHICH WILL ALLOW TEMPERATURES TO GET INTO THE MIDDLE OR MAYBE
UPPER 80S BY SATURDAY. ALONG THE COAST...TEMPERATURES GET INTO THE
LOW 70S BY WEDNESDAY...AND REMAIN ABOVE SEASONAL NORMAL THROUGH
SATURDAY. -MCCOY
&&
.AVIATION...A WEAK DISTURBANCE IS CURRENTLY MOVING ACROSS THE
REGION BRINGING AN INCREASE IN CLOUD COVER AND SOME SCATTERED
SHOWERS. THE MAIN FRONTAL SYSTEM WILL MOVE ACROSS THE REGION LATE
TONIGHT THROUGH SUNDAY MORNING. CONDITIONS LOOK TO REMAIN MOSTLY
VFR THROUGH TONIGHT. THE COAST WILL LIKELY LOWER TOWARDS
MVFR...AND POSSIBLY IFR...BETWEEN 06-10Z. THE INTERIOR LOOKS TO
REMAIN VFR...BUT BRIEF PERIODS OF REDUCED CIGS AND VSBY MAY BE
POSSIBLE UNDER HEAVIER RAIN BANDS AFTER 10Z. RAIN ACTIVITY AND
CLOUD COVER SHOULD DECREASE LATE SUNDAY.
KPDX AND APPROACHES...VFR THROUGH TONIGHT. SCATTERED SHOWERS
CONTINUE THROUGH THIS EVENING. CLOUD COVER AND RAIN CHANCES
INCREASE AFTER 10Z...WITH REDUCED CIGS AND VSBY POSSIBLE UNDER
HEAVIER RAIN BANDS. /64
&&
.MARINE...BENIGN WINDS AND SEAS CONTINUE THROUGH EARLY NEXT WEEK.
A WEAK FRONT MOVING ACROSS THE WATERS EARLY SUNDAY MORNING WILL
BRING A FEW HOURS OF SOUTHERLY WINDS...BUT WINDS SHOULD GENERALLY
REMAIN UNDER 20 KT. A FEW GUSTS TO 25 KT POSSIBLE UNDER HEAVIER
RAIN BANDS. HIGH PRESSURE REBUILDING OVER THE NORTHEAST PACIFIC
AND THERMAL LOW PRESSURE STRENGTHENING OVER SOUTHERN OREGON SHOULD
BRING GUSTY AFTERNOON/EVENING WINDS TO THE CENTRAL OREGON WATERS
THROUGH THE UPCOMING WEEK...WITH SOLID ADVISORY GUSTS DEVELOPING
LATE IN THE WEEK. A FEW WEAK DISTURBANCE MAY BRUSH THE NORTHERN
WATERS EARLY NEXT WEEK...BUT IMPACTS REMAIN MINIMAL.
SEAS REMAIN AROUND 4 TO 6 FT THROUGH MUCH OF THE UPCOMING WEEK.
MAY SEE SEAS CLIMB ABOVE 7 FT LATE NEXT WEEK...BUT CONFIDENCE IS
LOW. /64
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...NONE.
&&
$$
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
343 PM CDT SAT SEP 5 2015
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 342 PM CDT SAT SEP 5 2015
SHORT WAVE LIFTING NORTH NORTHEAST OUT OF NORTH CENTRAL NEBRASKA
WILL TRACK THROUGH SOUTH CENTRAL SOUTH DAKOTA INTO EAST CENTRAL
MINNESOTA LATE THIS EVENING. PLENTY OF LOW LEVEL MOISTURE AND WARM
AIR ADVECTION IS STREAMING ACROSS THE REGION AHEAD OF THIS WAVE. MID
AND HIGH CLOUDS BLANKETING OUR EASTERN HALF HAVE REALLY PREVENTED
TEMPERATURES FROM HEATING MUCH SO FAR TODAY. WITH THE FILTERED
SUNSHINE AND COOLER THAN EXPECTED TEMPERATURES...STRONG CAPPING
SHOULD PREVENT ANY SEVERE WEATHER FROM DEVELOPING THIS AFTERNOON AND
EVENING. THE HRRR AND NAM ARE FAR TOO AGGRESSIVE WITH DEVELOPING
CONVECTION...WHILE THE GFS...CANADIAN AND ECMWF PAINT VERY LITTLE
PRECIPITATION THROUGH MUCH OF THE OVERNIGHT. DID SOMETHING OF A
BLEND OF ALL OF THESE MODELS TO ACCOUNT FOR SOME ONGOING SCATTERED
SHOWER ACTIVITY WHICH THE LATER MODELS ARE NOT HANDLING WELL.
OTHERWISE...EXPECT THE SOME SCATTERED HIGH BASED SHOWERS LIFTING
INTO SOUTH CENTRAL SD TO CONTINUE LIFTING NORTH NORTHEAST ACROSS OUR
WESTERN HALF...WITH THE LINE SLOWLY SHIFTING EASTWARD THROUGH THE
OVERNIGHT HOURS. NOT SEEING MUCH LIGHTNING WITH THIS ACTIVITY...BUT
WE COULD SEE A FEW EMBEDDED CELLS BECOME MORE ORGANIZED WITH SOME
LIGHTNING STRIKES SO WILL LEAVE THE THUNDER MENTION IN PLACE. WHILE
THIS ACTIVITY MAY WAN SOME IN THE EARLY MORNING HOURS...THE LOW
LEVEL JET ONCE AGAIN KICKS IN LATE TONIGHT AND WILL LIKELY REIGNITE
SHOWERS AND STORMS. BY MID MORNING THE LOW LEVEL JET
WEAKENS...HOWEVER A COLD FRONT IS EXPECTED TO PUSH INTO THE WESTERN
FORECAST AREA AND GRADUALLY TRACK SOUTHEAST THROUGH THE FORECAST
AREA INTO THE AFTERNOON. BY MID AFTERNOON...THUNDERSTORM ACTIVITY
MAY INCREASE AGAIN IN THE AFTERNOON AHEAD OF THE FRONT IN OUR FAR
SOUTHEASTERN COUNTIES. THE BIG QUESTION WILL BE HOW WELL THIS AREA
WILL BE ABLE TO DESTABILIZE IN THE AFTERNOON. WITH CLOUDS AND
PRECIPITATION EARLY IN THE DAY...TEMPERATURES MAY NOT HEAT AS WELL
AS MODELS INDICATE. MEAGER SHEAR PROFILES BUT CONDITIONALLY GOOD
CAPE VALUES MAY ALLOW A FEW STRONG TO SEVERE STORMS TO FORM MID TO
AFTERNOON. WITH CLOUDS AROUND FOR MUCH OF THE DAY...HIGHS WILL BE
TRICKY. EXPECT MOST PLACES TO REACH THE LOW TO MID 80S.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 342 PM CDT SAT SEP 5 2015
CONVOLUTED FORECAST IN THE MEDIUM RANGE AS FORECAST IS VERY
DEPENDENT ON FRONTAL PLACEMENT. CURRENTLY...MODELS ARE OFFERING A
VARIETY OF SOLUTIONS IN TERMS OF FRONTAL PLACEMENT...MAKING FOR A
DIFFICULT FORECAST IN THE NEAR TERM. MODELS ARE DIFFERING WITHIN
THE TYPICAL BIAS REGIME...WITH THE GFS OFFERING A MORE PROGRESSIVE
SOLUTION THAN THE NAM AND REALITY LIKELY LYING IN THE MIDDLE. AHEAD
OF THE BOUNDARY...ATMOSPHERE IS UNSTABLE WITH 1000-1500 CAPE WITH
LIMITED CIN. SPC HAS EXPANDED SEVERE THREAT FOR DAY 2...BUT AM NOT
OVERLY EXCITED BY SEVERE THREAT WITH SHEAR VALUES FAIRLY LIMITED.
AM ONCE AGAIN CONCERNED ABOUT HEAVY RAIN POTENTIAL AND TRAINING OF
STORMS AHEAD OF THE FRONT...WITH PRECONVECTIVE PWAT VALUES NEAR
1.8"...NEAR RECORD LEVELS FOR THIS TIME OF YEAR.
THE BOUNDARY IS EXPECTED TO STALL OUT. CONSENSUS SUGGESTS THE
BOUNDARY WILL STALL JUST SOUTH OF THE FORECAST AREA...AND WITH THE
BOUNDARY HANGING AROUND..THERE IS LINGERING CHANCE OF PRECIPITATION
NEAR THE BOUNDARY. WITH FAIRLY STRONG SHORT WAVE TRACKING JUST SOUTH
OF THE FORECAST AREA ON MONDAY AFTERNOON INTO MONDAY NIGHT...HAVE
KEPT POPS IN THE SOUTH...BUT HAVE CUT POPS BACK ACROSS THE NORTH.
MODELS SUGGEST A STRONG COLD FRONT MOVING THROUGH THE AREA ON
WEDNESDAY. UPPER WAVE CONCENTRATED TO THE NORTH EAST...BUT A CHANCE
OF SHOWERS ACROSS THE AREA WITH VERY LIMITED INSTABILITY AS THE
FRONT MOVES THROUGH. HAVE CUT HIGHS BACK SOME ON WEDNESDAY WITH
CLOUDS AND FLOW BECOMING NORTHEAST.
COOL AND DRY CONDITIONS EXPECTED FOR THE REGION THROUGH THE
REMAINDER OF THE WEEK...WITH HIGHS 5-10 BELOW AVERAGE AND LOWS
AROUND 5 DEGREES BELOW NORMAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1249 PM CDT SAT SEP 5 2015
HIGH BASED CLOUDS AND CONVECTION WILL BE THE MAIN CONCERNS THROUGH
THE TAF PERIOD. EXPECT SOME SCATTERED SHRA TO TRACK FROM SOUTH
CENTRAL SD INTO NORTHEAST SD THIS AFTERNOON...WITH THIS BAND
NUDGING SLOWLY EASTWARD THROUGH THE OVERNIGHT HOURS.
ADDITIONALLY...A FEW MORE ORGANIZED TSRA MAY DEVELOP IN NORTH
CENTRAL NEBRASKA LATE AFTERNOON AND EVENING AND TRACK INTO OUR
WESTERN COUNTIES...ALLOWING FOR SOME MVFR VISIBILITY UNDER THE
STRONGER TSRA. FRONTAL BOUNDARY DROPPING INTO OUR WEST LATE
TONIGHT WILL APPROACH THE I29 CORRIDOR AROUND 18Z. EXPECT BREEZY
WINDS AHEAD OF AND BEHIND THE FRONT. LATE TONIGHT THERE MAY BE A
CONCERN WITH LOW LEVEL WINDS CREATING SOME WIND SHEAR CONCERNS AT
KSUX AND KHON THROUGH MID MORNING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...
LONG TERM...
AVIATION...
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1243 PM CDT SAT SEP 5 2015
.DISCUSSION...SEE 18Z AVIATION DISCUSSION.
&&
.AVIATION...WILL MAINTAIN THE VCSH/TEMPO SHRA AT KVCT BASED ON
RADAR AND HRRR DATA...BUT ONLY UNTIL 21Z/20Z...RESPECTIVELY AS
EXPECT ACTIVITY TO MOVE NORTH AFTER 21Z. NO CONVECTION MENTIONED
ELSEWHERE IN THE TERMINALS. GUSTY SSE WINDS THIS AFTERNOON LOSE
THEIR GUSTS ABOUT AN HOUR AFTER SUNSET (KLRD ABOUT 3 HOURS
AFTER)...THEN BECOME RELATIVELY LIGHT OVERNIGHT. COULD HAVE SOME
LIGHT FOG AGAIN AT KALI AND KVCT...BUT ONLY PUT IT IN FOR KVCT
SINCE BOUNDARY LAYER WINDS MAY BE A BIT TOO HIGH IN KALI AND HAVE
MVFR CIGS THERE. OTHERWISE...MVFR CIGS (AT LEAST TEMPO) AT KCRP
AND KALI BY 11Z...THEN END ABOUT 14Z. WINDS SOUTH AFTER SUNRISE
AROUND 11 KNOTS (MORE AT KCRP AND KLRD...LESS OTHER TWO SITE) FOR
THE REMAINDER OF THE TERMINAL FORECAST. NO CONVECTION EXPECTED AND
NONE MENTIONED IN THE TERMINALS FOR SUNDAY.
&&
.PREV DISCUSSION... /ISSUED 1015 AM CDT SAT SEP 5 2015/
DISCUSSION...A FEW CHANGES TO THE PREVIOUS FORECAST...MAINLY DEW
POINTS WHICH WERE TOO LOW IN A FEW LOCATIONS. STILL...GIVEN THE
UPDATED VALUES...HEAT INDICES BETWEEN 105 AND 109 ARE BEING
FORECAST (SPS HAS BEEN SENT OUT). WILL MONITOR AS THIS IS THE
LABOR DAY WEEKEND SO WILL HAVE TO KEEP A KEENER EYE ON THIS.
BOUNDARY LAYER WINDS A BIT HIGHER TODAY AND THE RIDGE A BIT
STRONGER...FEEL CONVECTION THIS AFTERNOON WILL BE MORE LIMITED AND
MAINLY OVER THE NORTHERN AREAS BEFORE ENDING BY LATE AFTERNOON.
THIS KIND OF FOLLOWS WHAT THE HRRR AND NSSL MODELS ARE INDICATING
SO ADJUSTED AFTERNOON POPS ACCORDINGLY. HIGH TEMPERATURE FORECAST
LOOKS REASONABLE. ADJUSTED CLOUD COVER TOO. MINOR ADJUSTMENTS TO
SECOND PERIOD TO ACCOUNT FOR FIRST PERIOD CHANGES. NO OTHER
UPDATES FOR OTHER PERIODS AT THIS TIME.
PREV DISCUSSION... /ISSUED 638 AM CDT SAT SEP 5 2015/
DISCUSSION...UPDATED FOR 12Z AVIATION.
AVIATION...POCKETS OF PATCHY FOG AND LOW CLOUDS HAVE DEVELOPED
THIS MORNING AND COULD IMPACT ALI/VCT/LRD FOR THE NEXT COUPLE OF
HOURS. ALSO...ISOLATED SHOWERS HAVE DEVELOPED NORTH OF PORT
ARANSAS INTO THE NORTHERN COASTAL BEND AND WILL CONTINUE TO MOVE
INLAND THIS MORNING. ONLY HAVE INCLUDED VCSH REMARKS FOR THE VCT
TERMINAL AS CONFIDENCE IS LOW TO MENTION PRECIP REMARKS AT THE
OTHER TERMINALS. WINDS WILL BE PREDOMINANTLY OUT OF THE SSE AND SE
WITH GUSTS AOA 20 KNOTS IN THE AFTERNOON. ANOTHER ROUND OF LOW
CLOUDS MAY DEVELOP LATE TONIGHT AND HAVE MENTIONED MVFR CIGS AT
ALI/VCT/CRP.
PREV DISCUSSION... /ISSUED 345 AM CDT SAT SEP 5 2015/
SHORT TERM (TODAY THROUGH SUNDAY)...UPPER LEVEL RIDGE WILL
BUILD OVER SOUTH TEXAS TODAY INTO SUNDAY. MOISTURE WILL BE A
LITTLE LESS TODAY AS MODELS PROG PW VALUES BETWEEN 1.7 TO 1.9
INCHES. ISOLATED CONVECTION OVER THE MARINE WATERS MAY APPROACH
THE COAST LATER THIS MORNING. THEN...DAYTIME HEATING COMBINED WITH
THE SEA BREEZE MAY BE ENOUGH TO GENERATE ISOLATED TO POSSIBLY
SCATTERED SHOWERS AND A FEW STORMS. LAST FEW RUNS OF THE HRRR AT
LEAST SUPPORT THIS TO SOME EXTENT...AND HAVE KEPT 20 POPS ACROSS
THE EAST WITH SOME 30 POPS ACROSS THE VICTORIA CROSSROADS.
CONDITIONS SHOULD BE A LITTLE WARMER TODAY COMPARED TO YESTERDAY
AS HIGHS CLIMB INTO THE LOWER 100S OUT WEST...TO MID/LOWER 90S
ACROSS THE EAST AND NORTHEAST. MOISTURE DECREASES A LITTLE MORE ON
SUNDAY AND GUIDANCE IS NOT TOO OPTIMISTIC ABOUT RAIN CHANCES. WILL
LEAVE RAIN CHANCES OUT OF THE FORECAST FOR NOW. ABOVE NORMAL
TEMPERATURES WILL CONTINUE ON SUNDAY.
LONG TERM (SUNDAY NIGHT THROUGH FRIDAY)...CHANGES IN THE UPPER
PATTERN TAKE PLACE BY SUNDAY NIGHT WITH H5 RIDGE FLATTENS AND SLIDES
WEST AS A TROUGH SWINGS EAST ACROSS THE HIGH PLAINS AND A WEAK CUT
OFF LOW DRIFTS WEST ALONG ACROSS THE GULF STATES INTO THE WESTERN
GULF. MODELS DISAGREE ON THE AMOUNT OF MOISTURE AVAILABLE...BUT
OVERALL...A RELATIVE INCREASE IN MOISTURE MOVES INTO THE WESTERN
GULF AS WELL AS THE EASTERN HALF OF THE CWA...AND IS DRAWN NORTH
INTO THE CENTRAL PLAINS. WITH WEAKNESS ALOFT AND SLIGHTLY COOL H85-
H7 TEMPS...DAILY CONVECTION IS EXPECTED THROUGH THE WEEK IN THE FORM
OF SHOWERS IN THE MORNING ACROSS THE GULF...MOVING INLAND WITH
HEATING. THE GFS AND EURO BOTH HINT AT A SURFACE FRONT TO MOVE
THROUGH THE CENTRAL PLAINS AND PUSH SOUTH INTO TEXAS. DISAGREEMENTS
DEVELOP BETWEEN THE LONG TERM MODELS ON THE DEVELOPMENT AND TIMING
OF THE FRONT FROM THURSDAY AND ONWARD. THIS SAID...MAINLY KEPT
SLIGHT CHANCE POPS FROM MONDAY THROUGH WEDNESDAY FOR ISOLATED
ACTIVITY ACROSS THE NORTHERN COASTAL BEND AND COASTAL PLAINS...WITH
20-30 POPS INTRODUCED BY FRIDAY DUE TO PROXIMITY OF THE BOUNDARY.
TEMPERATURES FOR THE MOST PART WILL BE SLIGHTLY ABOVE NORMAL THROUGH
MUCH OF THE WEEK...WITH COOLER TEMPS TOWARD THE LATER OF THE WORK
WEEK MAINLY DUE TO THE INCREASED CLOUD COVERAGE AND RAIN CHANCES.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 94 79 94 77 94 / 20 10 10 10 20
VICTORIA 94 76 96 75 95 / 30 10 10 10 20
LAREDO 102 79 102 77 102 / 10 10 0 0 10
ALICE 97 76 98 75 98 / 20 10 10 10 10
ROCKPORT 91 80 91 79 90 / 30 10 10 10 20
COTULLA 101 77 101 75 102 / 10 10 0 0 10
KINGSVILLE 96 78 97 76 97 / 20 10 10 10 10
NAVY CORPUS 90 80 90 80 90 / 20 10 10 10 20
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
GW/86...AVIATION
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
328 PM CDT SAT SEP 5 2015
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 328 PM CDT SAT SEP 5 2015
SURFACE OBSERVATIONS ACROSS THE REGION THIS AFTERNOON INDICATE A
STATIONARY FRONT POSITIONED FROM NEAR MANKATO MINNESOTA EAST TO THE
MISSISSIPPI RIVER EXTENDING SOUTHEAST THROUGH SOUTHWEST WISCONSIN. A
LOW LEVEL JET WAS FOCUSED INTO THE FRONT EARLIER TODAY AND
PRODUCED SHOWERS AND THUNDERSTORMS ACROSS PORTIONS OF SOUTHERN
MINNESOTA. THE SHOWERS AND STORMS GRADUALLY WEAKENED LATE THIS
MORNING AND ENDED EARLY THIS AFTERNOON. ABUNDANT MID TO HIGH LEVEL
CLOUDS WERE ACROSS THE FORECAST AREA TODAY THANKS TO THIS EARLY
DAY CONVECTION ACROSS MINNESOTA. FURTHER TO THE SOUTH...PARTLY TO
MOSTLY SUNNY SKIES HAVE ALLOWED TEMPERATURES TO SOAR INTO THE
UPPER 80S TO LOWER 90S ACROSS PORTIONS OF EASTERN AND NORTHERN
IOWA. INCREASING SOUTHERLY FLOW IS ADVECTING THIS WARMER AIR INTO
THE FORECAST AREA. IN ADDITION...WE ARE SEEING SOME
BREAKS/THINNING IN THE CLOUD COVER SO TEMPERATURES ARE GRADUALLY
WARMING ACROSS MUCH OF THE FORECAST AREA WITH MANY LOCATIONS
ALREADY CLIMBING INTO THE MID TO UPPER 80S. LOOK FOR THESE
TEMPERATURES TO CONTINUE TO CLIMB THIS AFTERNOON WITH HIGHS
RANGING FROM THE MID 80S ACROSS NORTHERN WISCONSIN TO AROUND 90S
ACROSS PORTIONS OF NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN.
LOW PRESSURE WILL TRACK FROM SOUTH DAKOTA INTO SOUTHWEST ONTARIO
TONIGHT THROUGH SUNDAY PUSHING A COLD FRONT TOWARDS THE FORECAST
AREA. ALSO...FLOW ALOFT WILL GRADUALLY TURN SOUTHWEST TONIGHT
INTO SUNDAY MORNING WITH A COUPLE OF WEAK SHORTWAVE TROUGHS MOVING
THROUGH. THESE WAVES COMBINED WITH WEAK MOISTURE TRANSPORT INTO
THE REGION MAY GENERATE ISOLATED SHOWERS AND THUNDERSTORMS
TONIGHT INTO SUNDAY MORNING. IF THESE DEVELOP...THEY WOULD MAINLY
BE FOCUSED ACROSS PORTIONS OF NORTHEAST IOWA...SOUTHEAST MINNESOTA
INTO PORTIONS OF WEST CENTRAL WISCONSIN. THE COLD FRONT WILL SLIDE
INTO THE FORECAST AREA BY SUNDAY AFTERNOON WITH SHOWERS AND STORMS
EXPECTED TO ERUPT ALONG THE FRONT. MESOSCALE MODELS ARE SHOWING
SOME DIFFERENCES IN TIMING THE FRONT INTO THE AREA. THE HI-RES ARW
IS INITIATING CONVECTION ACROSS WESTERN SECTIONS OF THE FORECAST
AREA BY MID AFTERNOON. THE LINE OF CONVECTION THEN SLIDES
SOUTHEAST THROUGH LATE AFTERNOON INTO THE EARLY EVENING HOURS AND
WEAKENS WITH TIME. THE HI-RES NMM JUST WEST OF THE FORECAST AREA
LATE IN THE AFTERNOON AND THEN TAKES THE LINE OF CONVECTION
EAST...SIMILAR TO THE ARW...BUT THEN ATTEMPTS TO SPLIT THE
CONVECTION INTO TWO SEGMENTS. ONE SEGMENT TRACKS ACROSS NORTH
CENTRAL WISCONSIN AND THE SECOND DIVES SOUTH INTO CENTRAL IOWA.
THE NAM NEST OFFERS A SIMILAR SOLUTION TO THE NMM. CAPE VALUES
WANE CONSIDERABLY EAST OF THE MISSISSIPPI RIVER SUNDAY EVENING SO
THINKING ANY CHANCES OF SEEING A FEW STRONG TO PERHAPS SEVERE
STORMS WOULD BE WEST OF THE MISSISSIPPI RIVER MAINLY DURING THE
MID TO LATE AFTERNOON ON SUNDAY. ALSO...SHEAR IS RATHER WEAK
ACROSS THE FORECAST AREA SUNDAY AFTERNOON INTO SUNDAY NIGHT WITH
0-3 KM BULK SHEAR VALUES IN THE 15 TO 20 KT RANGE. WE SHOULD SEE A
BROKEN LINE OF SHOWERS AND STORMS PUSH ACROSS THE FORECAST AREA
SUNDAY AFTERNOON INTO SUNDAY NIGHT...WITH A GRADUAL WEAKENING
TREND DURING THE EVENING INTO THE OVERNIGHT HOURS AS CAPE WANES.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 328 PM CDT SAT SEP 5 2015
THE COLD FRONT STALLS ACROSS NORTHERN IOWA INTO NORTHERN ILLINOIS MONDAY
INTO TUESDAY AS ANOTHER SHORTWAVE EJECTS OUT OF THE DESERT
SOUTHWEST. THIS WILL BRING A GOOD CHANCE OF SHOWERS AND STORMS TO
THE FORECAST AREA..ESPECIALLY FOR AREAS ALONG AND SOUTH OF
INTERSTATE 90. IN FACT...SOME HEAVY RAINFALL IS POSSIBLE ALONG THE
FRONT ACROSS CENTRAL IOWA INTO NORTHERN ILLINOIS. AT THIS
TIME...IT APPEARS THE FORECAST AREA WILL BE UNDER THE RIGHT
ENTRANCE REGION OF THE UPPER JET...PROVIDING SUPPORT FOR SHOWERS
AND EMBEDDED THUNDERSTORMS FROM LATE MONDAY INTO TUESDAY. THE
FRONT FINALLY PUSHES SOUTH OF THE REGION TUESDAY NIGHT INTO
WEDNESDAY WITH DRY HIGH PRESSURE BUILDING INTO THE UPPER
MISSISSIPPI RIVER VALLEY. A TROUGH THEN LOOKS TO PUSH THROUGH THE
REGION WEDNESDAY INTO THURSDAY CARVING OUT A MUCH BROADER TROUGH
ACROSS THE UPPER MISSISSIPPI RIVER VALLEY FOR LATE NEXT WEEK. ITS
LOOKING LIKE WE WILL SEE MUCH COOLER TEMPERATURES TO END NEXT WEEK
AS THIS TROUGH TAKES SHAPE. HIGHS FROM THURSDAY ALL THE WAY INTO
THE WEEKEND LOOK TO BE IN THE 60S WITH CHANCES FOR SHOWERS. IT
APPEARS FALL WEATHER WILL MAKE ITS APPEARANCE LATE NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1155 AM CDT SAT SEP 5 2015
CONVECTION OVER SOUTHERN MN HAS BEEN RELUCTANT TO DIE LATE THIS
MORNING...BEING FUELED BY THE LOW LEVEL JET/MOISTURE TRANSPORT. SOME
SIGNS THAT IT WAS WANING...BUT IT COULD LAST LONGER INTO THE
AFTERNOON THAN MESO MODELS SUGGEST - WHICH WEREN/T DOING A GREAT JOB
WITH IT ANYWAY. ULTIMATELY...DON/T THINK IT WILL IMPACT KRST ASIDE
FROM A VEIL OF MID/UPPER LEVEL CLOUDS...WHICH WILL ALSO HOLD ACROSS
KLSE.
TONIGHT SEE SOME POTENTIAL FOR ISOLATED SHRA/TS DEVELOPMENT. HINTS
IN THE RAP ON A BRANCH OF THE LOW LEVEL JET EDGING OVER THE LOCAL
AREA...WITH WEAK INSTABILITY A LOFT AND A MOISTURE FEED. NOT GOING TO
INCLUDE IN THE FORECAST AT THIS TIME...BUT THE POTENTIAL WILL HAVE
TO BE MONITORED.
SHRA/TS ARE LIKELY SUNDAY NIGHT AS A COLD FRONT SWEEPS IN FROM THE
WEST.
ONE LAST POTENTIAL CONCERN FOR TONIGHT IS THE POSSIBILITY OF LLWS.
RAP/HRRR/NAM BUFKIT SOUNDINGS ALL SUGGESTING BETWEEN 35-40 KTS BY
1500 FT. BORDERLINE LLWS IF SFC WINDS STAY UP TONIGHT AS FORECAST.
IF NOT...MAY NEED TO BE ADDED TO THE FORECAST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION.....RIECK
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND SUNDAY
ISSUED AT 251 PM CDT SAT SEP 5 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW LOW
PRESSURE CENTERED OVER NORTHWEST ONTARIO AND A CONNECTING COLD FRONT
RUNNING SOUTHWEST FROM THE LOW ACROSS THE DAKOTAS. AHEAD OF THE
FRONT...SHOWERS AND STORMS ARE OCCURRING WITH HELP FROM A SHORTWAVE
TROUGH. CLOSER TO HOME...A WEAK ELEVATED FRONT REMAINS OVER NE
WISCONSIN...AND CONTINUES TO KICK OFF ISOLATED SHOWERS. THE THREAT
FOR SHOWERS SHOULD COME TO AN END BY LATE THIS AFTERNOON AS THIS
BOUNDARY EXITS. AS THE SHORTWAVE ARRIVES LATE TONIGHT...FOLLOWED BY
THE COLD FRONT LATE ON SUNDAY...SHOWER AND THUNDERSTORM CHANCES ARE
THE MAIN FORECAST CONCERN.
TONIGHT...MID-LEVEL RIDGING WILL HANG OVERHEAD FOR MUCH OF THE
NIGHT. SOUTHWEST MID-LEVEL WINDS WILL ADVECT IN CLOUDS GENERALLY
ABOVE 12KFT THAT ARE CURRENTLY OVER SOUTHWEST WISCONSIN FOR THE
EVENING. THEN THE TAIL END OF A SHORTWAVE WHICH WILL LIFT INTO
ONTARIO WILL GRAZE NORTH-CENTRAL WISCONSIN OVERNIGHT. THIS
SHORTWAVE IN COMBINATION WITH INCREASING MID-LEVEL THETAE AND LLJ
MAY GENERATE A FEW SHOWERS AND STORMS OVER N-C WISCONSIN LATE.
CONFIDENCE IS RATHER LOW SO WILL KEEP PRECIP CHANCES AT OR BELOW 30
PCT. THE PRESSURE GRADIENT WILL BE TIGHTENING SO SHOULD SEE A
STEADY SOUTHEAST TO SOUTH WIND THROUGH THE NIGHT. THIS SHOULD
PROHIBIT DENSE FOG FROM FORMING...EXCEPT NEAR LAKE MICHIGAN WHERE
ONSHORE FLOW WILL BE OCCURRING. MUGGY LOWS IN THE UPPER 60S TO LOW
70S.
SUNDAY...A CHANCE OF SPOTTY SHOWERS AND STORMS WILL CONTINUE THROUGH
THE MORNING...MAINLY OVER N-C WISCONSIN...THOUGH AM NOT EXPECTING
MUCH ACTIVITY UNTIL INSTABILITY INCREASES LATER IN THE DAY. AS A
COLD FRONT MOVES INTO THE NORTHERN MISSISSIPPI VALLEY...THE PWAT
PLUME IN EXCESS OF 2.0 INCHES WILL SPREAD EAST ACROSS CENTRAL AND
NORTH-CENTRAL WISCONSIN DURING THE AFTERNOON. CONVECTIVE TEMPS WILL
ONLY BE IN THE MID 80S...AND PROGGED SOUNDINGS INDICATE LITTLE
CAPPING WHILE ML CAPES REACH TO AROUND 2000 J/KG. SO CONDITIONS
LOOK GOOD FOR SCT THUNDERSTORM DEVELOPMENT BY MID-AFTERNOON. WINDS
ALOFT ALSO INCREASE LATE IN THE AFTERNOON...WHICH COULD GIVE AN
ISOLATED DAMAGING WIND THREAT WITHIN ANY THUNDERSTORMS.
OTHERWISE...THE SKINNY CAPES AND HIGH PWATS SHOULD PRODUCE HEAVY
RAIN MAKERS. VERY WARM AND MUGGY WITH HIGHS RANGING FROM THE MID
80S NORTH TO NEAR 90 SOUTH.
.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY
ISSUED AT 251 PM CDT SAT SEP 5 2015
A COLD FRONT SHOULD MOVE SLOWLY ACROSS WISCONSIN SUNDAY NIGHT AND
BECOME STATIONARY OVER NORTHERN ILLINOIS MONDAY. MODEL THEN BRING
A SURFACE WAVE NORTHEAST AND PUSH THE FRONT BACK NORTH TUESDAY.
THERE ARE DIFFERENCES IN THE TIMING AND NORTHWARD EXTENT OF THE
SHOWERS AND THUNDERSTORMS ASSOCIATED WITH THE FEATURE BUT IT LOOKS
LIKE THE BULK OF THE PRECIPITATION WILL BE ACROSS THE SOUTHEAST
HALF OF OUR FORECAST AREA.
THE FRONT GETS A SHOVE TO THE SOUTH TUESDAY NIGHT WITH DRY AND
COOLER CONDITIONS EXPECTED WEDNESDAY THROUGH PART OF THURSDAY
BEFORE AN UPPER TROUGH SWINGS THROUGH WITH POSSIBLE SHOWERS
THURSDAY NIGHT AND FRIDAY. TEMPERATURES WILL REMAIN WARMER THAN
NORMAL THROUGH THE MIDDLE OF THE WEEK AND THEN FALL TO NORMAL OR
EVEN A BIT COOLER THAN NORMAL BY THE END OF THE WEEK AS HEIGHTS
FALL.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1200 PM CDT SAT SEP 5 2015
ISOLATED SHOWERS ARE POSSIBLE ALONG A WEAK BOUNDARY THAT
WILL RETREAT TO THE NORTHEAST OVER NORTHEAST WISCONSIN THROUGH MID-
AFTERNOON. THEREAFTER...WILL GRADUALLY SEE AN INCREASE OF MID-
CLOUDS. THE COMBO OF CLOUDS AND A SOUTHERLY BREEZE SHOULD PREVENT
WIDESPREAD FOG FROM FORMING...EXCEPT ALONG LAKE MICHIGAN. DID BACK
OFF FOG IMPACTS AS STATISTICAL AND UPS FOG TECHINIQUE ARE MORE
OPTIMISTIC. ANY LOWER VSBYS SHOULD IMPROVE QUICKLY SUNDAY MORNING.
THE CHANCE OF SHOWERS AND STORMS THOUGH WILL INCREASE WITH HEATING
OF THE DAY ON SUNDAY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......RDM
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1155 AM CDT SAT SEP 5 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 250 AM CDT SAT SEP 5 2015
FORECAST FOCUS IS ON RAIN CHANCES TODAY WITH WEAK DISTURBANCE
MOVING THROUGH THE REGION. AMOUNT OF CLOUD COVER AND RESULTING
TEMPERATURES THEN ON THE FOREFRONT.
REGIONAL RADAR LOOPS SHOW NARROW BAND OF SHOWERS MOVING SLOWLY
EAST THROUGH THE FORECAST AREA...LOCATED RIGHT ALONG THE
MISSISSIPPI RIVER AT 07Z. THIS OCCURRING IN A FAVORABLE
THERMODYNAMIC FORCING RIBBON. THIS EXPECTED TO TRANSLATE EAST
AND WEAKEN WITH TIME THIS MORNING. ONCE THIS AREA MOVES OFF...
HAZY SUNSHINE AND HUMID CONDITIONS WILL ONCE AGAIN PREVAIL SIMILAR
TO THE PAST FEW DAYS. MODELS ALL POINT TO ANOTHER WEAK SHORT WAVE
TROUGH MOVING NORTHEAST UP THE RIDGE AND INTO WESTERN MN BY
EVENING. THIS SHOULD HELP FIRE CONVECTION TO THE WEST OF THE
FORECAST AREA...AND SOME OF THIS COULD TRY AND SNEAK IN TO THE
WESTERN FRINGES OF OUR FORECAST AREA OVERNIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 250 AM CDT SAT SEP 5 2015
A PATTERN SHIFT WILL TAKE PLACE AS THE UPPER RIDGE SHIFTS EAST AND
FLATTENS IN RESPONSE TO THE LARGER WESTERN LONG WAVE TROUGH
OPENING AND EJECTING NORTHEAST INTO SOUTHERN CANADA BY SUNDAY. AS
THE FORCING FROM THE MAIN WAVE PASSES...IT SENDS A COLD FRONT
THROUGH THE LOCAL AREA LATE SUNDAY. WARM AIR AND DEEP MIXING AHEAD
OF THE FRONT WILL KEEP TEMPERATURES AND HEAT INDEX VALUES UP FOR
ONE LAST DAY. CAPE IS EXPECTED TO RISE TO 1500-2000 J/KG BUT SHEAR
WILL BE LIMITED...LAGGING THE FRONTAL PASSAGE. SOME STRONG STORMS
ARE POSSIBLE BUT NOT VERY CONFIDENT IN ANY SIGNIFICANT SEVERE
POTENTIAL. RAIN WILL END AND MUCH MORE SEPTEMBER-LIKE TEMPERATURES
ANTICIPATED BEHIND THE FRONT NEXT WEEK. AS UPPER FLOW BECOMES
ZONAL TO SLIGHTLY NORTHWEST...SOME WEAK RIPPLES WILL BE
TRANSITIONING THROUGH THE AREA. ONE SUCH DISTURBANCE MAY BRING
RAIN MONDAY NIGHT AND TUESDAY...WITH ANOTHER WEDNESDAY NIGHT INTO
THURSDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1155 AM CDT SAT SEP 5 2015
CONVECTION OVER SOUTHERN MN HAS BEEN RELUCTANT TO DIE LATE THIS
MORNING...BEING FUELED BY THE LOW LEVEL JET/MOISTURE TRANSPORT. SOME
SIGNS THAT IT WAS WANING...BUT IT COULD LAST LONGER INTO THE
AFTERNOON THAN MESO MODELS SUGGEST - WHICH WEREN/T DOING A GREAT JOB
WITH IT ANYWAY. ULTIMATELY...DON/T THINK IT WILL IMPACT KRST ASIDE
FROM A VEIL OF MID/UPPER LEVEL CLOUDS...WHICH WILL ALSO HOLD ACROSS
KLSE.
TONIGHT SEE SOME POTENTIAL FOR ISOLATED SHRA/TS DEVELOPMENT. HINTS
IN THE RAP ON A BRANCH OF THE LOW LEVEL JET EDGING OVER THE LOCAL
AREA...WITH WEAK INSTABILITY A LOFT AND A MOISTURE FEED. NOT GOING TO
INCLUDE IN THE FORECAST AT THIS TIME...BUT THE POTENTIAL WILL HAVE
TO BE MONITORED.
SHRA/TS ARE LIKELY SUNDAY NIGHT AS A COLD FRONT SWEEPS IN FROM THE
WEST.
ONE LAST POTENTIAL CONCERN FOR TONIGHT IS THE POSSIBILITY OF LLWS.
RAP/HRRR/NAM BUFKIT SOUNDINGS ALL SUGGESTING BETWEEN 35-40 KTS BY
1500 FT. BORDERLINE LLWS IF SFC WINDS STAY UP TONIGHT AS FORECAST.
IF NOT...MAY NEED TO BE ADDED TO THE FORECAST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...MW
LONG TERM....MW
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1144 AM MDT SAT SEP 5 2015
.UPDATE...
ISSUED AT 951 AM MDT SAT SEP 5 2015
A FEW LIGHT SHOWERS AND SPRINKLES MOVING ACROSS NORTHERN PORTIONS
OF THE NEBRASKA PANHANDLE AT THIS TIME. THIS AREA OF SHOWERS WILL
QUICKLY MOVE OUT OF THE AREA BEFORE MORNINGS END BUT MORE SHOWER
ACTIVITY TO DEVELOP ACROSS THE FORECAST AREA THIS AFTERNOON.
UPDATED POP AND SKY COVER FORECAST TO REFLECT CURRENT CONDITIONS
AND TWEAKED CHANCES FOR SHOWERS AND THUNDERSTORMS THIS AFTERNOON.
BASED ON THE HRRR MODEL PERFORMANCE THE LAST FEW DAYS...ADDED
ISOLATED SHOWERS AND THUNDERSTORMS TO THE ENTIRE WESTERN NEBRAKSA
PANHANDLE THIS AFTERNOON.
ONCE AGAIN VERY LITTLE IN THE WAY OF MEASURABLE PRECIPITATION IS
EXPECTED. MAINLY LOOKING FOR A TRACE TO A FEW HUNDRETHS OF AN INCH
OF PRECIPITATION WITH LOCALLY HIGHER AMOUNTS WITH ANY THUNDERSTORM
ACTIVITY. THUNDERSTORMS WILL BE FEW AND FAR BETWEEN. INVERTED V
SOUNDINGS WILL ONCE AGAIN SUGGESTIVE OF GUSTY DOWNDRAFT/OUTFLOW
WINDS WITH SOME SHOWERS AND THUNDERSTORMS TODAY. GUSTS OF 40 TO 50
MPH LIKELY WITH SOME SHOWERS AND THUNDERSTORMS.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 303 AM MDT SAT SEP 5 2015
PREDAWN WATER VAPOR IMAGERY DEPICTED A UPPER TROUGH OVER THE
NORTHWEST CONUS WITH A LOW CENTERED OVER OR. A LARGE UPPER RIDGE
ENCOMPASSED THE EASTERN 2/3 OF THE NATION. SUBTROPICAL/MONSOON
MOISTURE CONTINUED TO STREAM NORTHEAST FROM BAJA CA INTO THE
ROCKIES AND HIGH PLAINS. A PASSING WEAK SHORT WAVE OVER FAR
SOUTHEAST WY AND WESTERN NE PRODUCED SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS. THIS ACTIVITY WILL END BY DAYBREAK. SKIES
WERE MOSTLY CLOUDY WITH LIGHT WINDS AND TEMPERATURES IN THE 50S
AND 60S.
THE SHORT RANGE MODELS HAVE MAINTAINED THEIR RUN-TO-RUN CONSISTENCY
FOR SEVERAL DAYS PROGGING THE PACIFIC NORTHWEST UPPER LOW TO LIFT
NORTHEAST THROUGH ID AND MT DURING THE NEXT 24 HOURS. THE MOIST
SOUTHWEST FLOW ALOFT WILL PROVIDE CHANCES FOR SHOWERS AND ISOLATED
THUNDERSTORMS FROM LATE THIS MORNING THROUGH THE AFTERNOON AND
EVENING...ESPECIALLY WEST OF I-25. GUSTY WINDS UP TO 45 MPH...
LIGHTNING AND BRIEF MODERATE TO HEAVY RAIN WILL BE THE PRIMARY
HAZARDS. OUTSIDE OF THE CONVECTION...SOUTHWEST WINDS WILL GUST TO
35 MPH WEST OF THE LARAMIE RANGE. IT WILL BE ANOTHER WARM AFTERNOON
FOR THE PLAINS WITH HIGHS IN THE 80S TO AROUND 90.
A PACIFIC COLD FRONT IS FORECAST TO MOVE EAST ACROSS THE CWA LATE
TONIGHT AND EARLY SUNDAY MORNING...USHERING IN A DRIER AND MORE
STABLE AIR MASS. WEST TO NORTHWEST WINDS WILL INCREASE TO 25 TO
35 MPH BEHIND THE FRONT SUNDAY MORNING...WITH HIGHER GUSTS
POSSIBLE IN WIND PRONE AREAS OF SOUTHEAST WY. SUNDAY WILL BE 5 TO
10 DEGREES COOLER WITH HIGHS IN THE 70S TO LOWER 80S.
MONDAY WILL BE A PLEASANT DAY WITH NEAR SEASONABLE TEMPERATURES. A
WEAK SURFACE TROUGH IS PROGGED BY MOST OF THE MODELS TO SET UP NEAR
THE WY-NE BORDER MONDAY WITH A FEW SHOWERS OR THUNDERSTORMS POSSIBLE
OVER THE FAR SOUTHEAST PART OF THE CWA...ROUGHLY EAST OF A ALLIANCE
TO SIDNEY LINE. BREEZY WEST WINDS WILL DEVELOP ALONG AND WEST OF
THE LARAMIE RANGE MONDAY AFTERNOON.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 300 AM MDT SAT SEP 5 2015
A LOW AMPLITUDE CYCLONIC UPPER FLOW SHOULD EXIST OVER SRN CANADA
AND THE NORTHERN TIER STATES MOST OF NEXT WEEK. SEVERAL UPPER
SHORT WAVES WILL TRANSLATE EAST ACROSS THE REGION IN THIS FLOW
PATTERN BRINGING SURGES OF COOLER AIR. ONE MINOR FRONT WILL SCOOT
ACROSS MONDAY NIGHT BUT HAVE LITTLE EFFECT ON THE SENSIBLE WEATHER
ACROSS THE CWA WITH WARM AND DRY WEATHER EXPECTED FOR TUESDAY AND
WEDS. A LITTLE STRONGER FRONT LOOKS TO PASS ACROSS LATER WEDS BUT
AGAIN LOOKS DRY. MILD TEMPS THURSDAY THEN A STRONGER SHORTWAVE
WILL MOVE SOUTHEAST OUT OF SOUTHERN CANADA INTO THE PLAINS THURSDAY
NIGHT DRIVING YET ANOTHER PUSH OF COOLER AIR SOUTH OUT OF CANADA
AND REINFORCING THE MILD AIR MASS OVER THE REGION. THIS SYSTEM MAY
BRING A FEW SHOWERS TO MAINLY THE PANHANDLE FRIDAY IN ASSOCIATION
WITH THE PASSING OF THE SHORT WAVE...THOUGH BETTER ENERGY SHOULD
PASS TO THE EAST OF THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1140 AM MDT SAT SEP 5 2015
A FEW LIGHT SHOWERS OR SPRINKLES MAY DEVELOP OVER THE AREA THIS
AFTERNOON...BUT THIS ACTIVITY WILL BE FEW AND FAR BETWEEN.
OUTSIDE ANY SHOWERS...WIND SPEEDS WILL GENERALLY BE LESS THAN
15KTS EAST OF THE LARAMIE RANGE THIS AFTERNOON. MEANWHILE...TAF
SITES SUCH AS LARAMIE AND RAWLINS WILL HAVE GUSTY SOUTHWEST WINDS
TODAY AT SPEEDS OF 20 TO 30 MPH WITH SOME GUSTS UP TO 35 MPH
POSSIBLE AS THE UPPER LEVEL DISTURBANCE IN THE NORTHWEST U.S. BEGINS
TO SHIFT NORTHEAST.
COX
&&
.FIRE WEATHER...
ISSUED AT 300 AM MDT SAT SEP 5 2015
MOIST SOUTHWEST FLOW ALOFT WILL PRODUCE SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS TO MOST OF THE FORECAST AREA THIS AFTERNOON
AND EVENING. THERE IS A LOW RISK OF DRY LIGHTNING. CRITICAL FIRE
WEATHER CONDITIONS WILL DEVELOP SUNDAY FOLLOWING THE PASSAGE OF A
COLD FRONT. WESTERLY WINDS WITH FREQUENT GUSTS OF 30 TO 40 MPH ARE
EXPECTED. DESPITE THE COOLER TEMPERATURES...RELATIVE HUMIDITIES
WILL FALL TO 10 TO 15 PERCENT SUNDAY AFTERNOON OVER PORTIONS OF
EAST AND SOUTH CENTRAL WYOMING.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...FIRE WEATHER WATCH FROM SUNDAY MORNING THROUGH SUNDAY EVENING
FOR WYZ301>303-308.
NE...NONE.
&&
$$
UPDATE...SML
SHORT TERM...MAJ
LONG TERM...RE
AVIATION...REC
FIRE WEATHER...MAJ