Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/09/15
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
642 PM CDT SAT AUG 8 2015
.AVIATION...
A FEW THUNDERSTORMS DEVELOPED THIS AFTERNOON BUT ALL HAVE
DISSIPATED AT THIS TIME IN THE CWFA. PATCHY FOG IS EXPECTED IN THE
MORNING WITH MVFR CONDITIONS AND HIGH PRESSURE IN PLACE OVER THE
AREA. MAINLY SCATTERED CUMULUS ARE EXPECTED SUNDAY WITH VFR
CONDITIONS.
&&
.PREV DISCUSSION... /ISSUED 304 PM CDT SAT AUG 8 2015/
SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT
A FEW ISOLATED SHOWERS AND THUNDERSTORMS HAVE POPPED UP ACROSS THE
STATE DURING THE LAST COUPLE OF HOURS AND THESE HAVE BEEN EXTREMELY
ISOLATED IN NATURE. WITH A STALLED BOUNDARY ACROSS THE STATE...DO
EXPECT A FEW MORE SHOWERS AND THUNDERSTORMS TO POP UP IN THE HEAT OF
THE DAY...WHICH THE HRRR HAS BEEN CONSISTENT IN SHOWING AS WELL.
SUNDAY WILL BE SLIGHTLY HOTTER AS THE RIDGE BUILDS INTO THE
AREA...THE AXIS OF HIGHEST DEW POINTS WILL SHIFT A BIT MORE TO THE
EAST. AS A RESULT...THIS WILL ADD NE ARKANSAS INTO THE HEAT ADVISORY.
A HOT DAY CAN BE EXPECTED ON MONDAY AS WELL WITH SLIGHTLY LOWER DEW
POINTS. AT THIS POINT IT APPEARS THE ONLY AREAS ABLE TO REACH
EXCESSIVE HEAT WARNING CRITERIA WILL BE ACROSS SE PORTIONS OF THE
CWA...BUT AT THIS POINT ITS BORDERLINE. WILL DEFER TO THE MID
SHIFT...AS THE NUMBERS ARE SO CLOSE TO CRITERIA. A FRONT WILL MOVE
THROUGH THE STATE ON MONDAY...WITH LITTLE IN THE WAY OF
PRECIPITATION EXPECTED UNTIL THE FRONT REACHES SOUTHERN ARKANSAS. IT
CONTINUES TO LOOK THAT THE BEST CHANCES FOR PRECIPITATION WILL BE TO
THE SOUTH OF THE STATE...BUT DID GO AND INCLUDE SLIGHT CHANCE POPS
ACROSS SOUTHERN PORTIONS OF THE STATE.
LONG TERM...WEDNESDAY THROUGH FRIDAY
SOME EXCESSIVE HEAT RELIEF IS IN STORE BEGINNING WEDNESDAY. AS
THE UPPER RIDGE SHIFTS WEST ALLOWING AND IN THE WAKE OF A WEAK
COLD FRONT MAX TEMPS DURING THIS PERIOD WILL RUN AT OR BELOW
NORMAL. DRIER CONDITIONS AS WELL AS DEWPOINTS FALL INTO THE UPPER
50S TO MID 60S. LOOKS TO BE A DRY PERIOD AS STABLE NORTHERLY FLOW
ALOFT AND WEAK NE SURFACE FLOW DOMINATE AND EMBEDDED UPPER LEVEL
DISTURBANCES SEEM UNLIKELY AT THIS TIME.
&&
.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR 74 99 79 98 / 0 0 10 20
CAMDEN AR 77 104 78 103 / 0 0 10 10
HARRISON AR 74 97 74 94 / 0 0 10 20
HOT SPRINGS AR 78 103 78 102 / 0 0 10 10
LITTLE ROCK AR 77 103 80 102 / 0 0 10 10
MONTICELLO AR 77 103 80 103 / 0 0 10 10
MOUNT IDA AR 75 102 74 102 / 0 0 10 10
MOUNTAIN HOME AR 74 98 75 96 / 0 0 10 20
NEWPORT AR 73 98 77 96 / 0 0 10 20
PINE BLUFF AR 76 103 78 101 / 0 0 10 10
RUSSELLVILLE AR 76 101 75 101 / 0 0 10 10
SEARCY AR 73 100 76 98 / 0 0 10 20
STUTTGART AR 75 101 77 99 / 0 0 10 20
&&
.LZK WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR BAXTER-BOONE-
CLEBURNE-INDEPENDENCE-JACKSON-MARION-MONROE-NEWTON-SEARCY-STONE-
VAN BUREN-WOODRUFF.
HEAT ADVISORY FROM 11 AM TO 8 PM CDT SUNDAY FOR BAXTER-BOONE-
CLEBURNE-FULTON-INDEPENDENCE-IZARD-JACKSON-MARION-NEWTON-SEARCY-
SHARP-STONE-VAN BUREN.
EXCESSIVE HEAT WARNING UNTIL 8 PM CDT THIS EVENING FOR ARKANSAS-
BRADLEY-CALHOUN-CLARK-CLEVELAND-CONWAY-DALLAS-DESHA-DREW-
FAULKNER-GARLAND-GRANT-HOT SPRING-JEFFERSON-JOHNSON-LINCOLN-
LOGAN-LONOKE-MONTGOMERY-OUACHITA-PERRY-PIKE-POLK-POPE-PRAIRIE-
PULASKI-SALINE-SCOTT-WHITE-YELL.
EXCESSIVE HEAT WARNING FROM 11 AM TO 8 PM CDT SUNDAY FOR
ARKANSAS-BRADLEY-CALHOUN-CLARK-CLEVELAND-CONWAY-DALLAS-DESHA-
DREW-FAULKNER-GARLAND-GRANT-HOT SPRING-JEFFERSON-JOHNSON-LINCOLN-
LOGAN-LONOKE-MONROE-MONTGOMERY-OUACHITA-PERRY-PIKE-POLK-POPE-
PRAIRIE-PULASKI-SALINE-SCOTT-WHITE-WOODRUFF-YELL.
HEAT ADVISORY FROM 11 AM TO 8 PM CDT MONDAY FOR ARKANSAS-BRADLEY-
CALHOUN-CLARK-CLEBURNE-CLEVELAND-CONWAY-DALLAS-DESHA-DREW-
FAULKNER-GARLAND-GRANT-HOT SPRING-JACKSON-JEFFERSON-JOHNSON-
LINCOLN-LOGAN-LONOKE-MONROE-MONTGOMERY-OUACHITA-PERRY-PIKE-POLK-
POPE-PRAIRIE-PULASKI-SALINE-SCOTT-VAN BUREN-WHITE-WOODRUFF-YELL.
&&
$$
AVIATION...51
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
239 PM CDT FRI AUG 7 2015
.SHORT TERM...TONIGHT THROUGH MONDAY NIGHT
AN AREA OF SHOWERS AND THUNDERSTORMS MOVED FROM SOUTH CENTRAL
MISSOURI AND TRACKED SOUTHEAST THROUGH PORTIONS OF EASTERN ARKANSAS.
THESE STORMS CONTINUED TO STRENGTHEN DURING THE MID MORNING HOURS
AND LED TO INCREASED CLOUD COVER THROUGH THE EASTERN HALF OF THE
STATE. BY THE EARLY AFTERNOON HOURS...MOSTLY SUNNY SKIES WERE SEEN
AROUND THE STATE WITH TEMPERATURES WARMING INTO THE MID TO UPPER 90S
WITH A FEW LOCATIONS IN WESTERN ARKANSAS ALREADY TOPPING 100
DEGREES. HEAT INDICES AROUND THE STATE HAVE REACHED 112 AT
RUSSELLVILLE WITH A FEW LOCATIONS TOPPING 110.
FOR TONIGHT...KEPT SLIGHT CHANCE POPS ACROSS EASTERN PORTIONS OF THE
AREA WITH BOTH THE HRRR AND WRF SHOWING REDEVELOPMENT ACROSS EASTERN
ARKANSAS.
IN THE COMING DAYS...WILL CONTINUE TO SEE A STRONG RIDGE OF HIGH
PRESSURE BUILD INTO THE REGION WITH TEMPERATURES EXPECTED TO CLIMB
EVEN HOTTER THAN WHAT HAS BEEN SEEN TODAY. FOR NOW...HAVE EXTENDED
AND EXPANDED THE EXCESSIVE HEAT WARNING INTO SATURDAY AND CONTINUED
WITH THE HEAT ADVISORY AT THE REMAINING COUNTIES EXCEPT ACROSS
NORTHEAST ARKANSAS.
HOT TEMPERATURES WILL CONTINUE ON SUNDAY WITH FEWER CLOUDS AND
SLIGHTLY LOWER DEWPOINTS...GENERALLY ACROSS SOUTHWEST AND CENTRAL
ARKANSAS. HOWEVER DEWPOINTS WILL GENERALLY INCREASE ACROSS NORTHEAST
ARKANSAS WHICH WILL LIKELY CAUSE HEAT ADVISORIES/WARNINGS TO BE
EXTENDED AND EXPANDED.
UPPER LEVEL RIDGE WILL BEGIN TO RETREAT ON MONDAY...ALLOWING A COLD
FRONT TO APPROACH THE STATE FROM THE NORTH. AT THIS POINT...IT DOES
NOT APPEAR THAT THERE WILL BE HIGH CHANCE FOR PRECIPITATION WITH
THIS FRONT...BUT SLIGHTLY COOLER TEMPS AND DRIER AIR WILL MOVE INTO
THE STATE FOR THE LONG TERM.
&&
.LONG TERM...TUESDAY THROUGH FRIDAY NIGHT
THE UPPER LEVEL RIDGE OF HIGH PRESSURE THAT HAS PERSISTED OVER THE
REGION FOR THE PAST SEVERAL WEEKS WILL RETREAT WESTARD DURING THE
EXTENDED TERM...CHANGING THE UPPER LEVEL FLOW PATTERN TO A
NORTHERLY TO NORTHWESTERLY FLOW. AT THE SURFACE A HIGH PRESSURE
SYSTEM WILL SLOWLY MOVE TO THE EAST ACROSS THE UPPER MIDWEST INTO
THE OHIO VALLEY...KEEPING THE FORECAST AREA ALONG THE SOUTHERN
PERIPHERY OF THE HIGH. THIS WILL RESULT IN A DRY NORTHERLY TO
NORTHEASTERLY SURFACE FLOW.
THIS SETUP WILL ALLOW TEMPERATURES TO REMAIN JUST A BIT COOLER THAN
THEY HAVE BEEN AT PRESENT...MOST NOTABLY ACROSS THE NORTHERN HALF OF
THE AREA. SURFACE DEWPOINTS WILL EVENTUALLY DROP DOWN TO BE ABOUT 10
TO 15 DEGREES LOWER THAN THEY ARE RIGHT NOW...WHICH WILL BE A
WELCOME RELIEF...PUSHING MAXIMUM APPARENT TEMPERATURES DOWN INTO THE
MID 80S ACROSS THE NORTH TO THE MID 90S ACROSS THE SOUTH.
WITH THE NORTH TO NORTHWESTERLY FLOW AT THE UPPER LEVELS...A
SHORTWAVE OR TWO COULD RIPPLE ACROSS THE FORECAST AREA DURING THE
EXTENDED TERM...AND ISOLATED SHOWERS AND THUNDERSTORMS CANNOT BE
RULED OUT. HOWEVER...WITH THE MOISTURE LEVELS REMAINING LOWER...THE
CHANCES FOR PRECIPITATION SHOULD BE RATHER LOW...AND BELOW MENTION
IN MANY AREAS.
&&
.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR 74 93 76 100 / 20 10 0 10
CAMDEN AR 80 102 79 103 / 10 10 0 10
HARRISON AR 74 96 74 98 / 20 10 0 10
HOT SPRINGS AR 79 102 78 102 / 10 10 0 10
LITTLE ROCK AR 78 100 79 102 / 20 10 0 10
MONTICELLO AR 79 103 79 104 / 20 10 0 10
MOUNT IDA AR 74 102 74 102 / 10 10 0 10
MOUNTAIN HOME AR 73 95 74 100 / 20 10 0 10
NEWPORT AR 73 94 75 97 / 20 10 0 10
PINE BLUFF AR 77 100 78 101 / 20 10 0 10
RUSSELLVILLE AR 78 101 75 102 / 10 10 0 10
SEARCY AR 76 96 75 100 / 20 10 0 10
STUTTGART AR 76 96 76 99 / 20 10 0 10
&&
.LZK WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY FROM 7 AM SATURDAY TO 7 PM CDT SUNDAY FOR BAXTER-
BOONE-INDEPENDENCE-JACKSON-MARION-NEWTON-SEARCY-STONE.
EXCESSIVE HEAT WARNING UNTIL 7 PM CDT SATURDAY FOR BRADLEY-
CALHOUN-CLARK-CLEVELAND-CONWAY-DALLAS-DESHA-DREW-FAULKNER-
GARLAND-GRANT-HOT SPRING-JEFFERSON-JOHNSON-LINCOLN-LOGAN-LONOKE-
OUACHITA-PERRY-POPE-PULASKI-SALINE-YELL.
EXCESSIVE HEAT WARNING FROM 7 AM TO 7 PM CDT SATURDAY FOR
ARKANSAS-MONTGOMERY-PIKE-POLK-PRAIRIE-SCOTT-WHITE.
HEAT ADVISORY UNTIL 7 AM CDT SATURDAY FOR ARKANSAS-MONTGOMERY-
PIKE-POLK-PRAIRIE-SCOTT-WHITE.
HEAT ADVISORY UNTIL 7 PM CDT SUNDAY FOR CLEBURNE-MONROE-VAN
BUREN-WOODRUFF.
&&
$$
SHORT TERM...65 / LONG TERM...53
AREA FORECAST DISCUSSION...UPDATE FOR AVIATION
NWS LITTLE ROCK AR
1240 AM CDT FRI AUG 2015
.AVIATION...
FORECAST WILL START WITH VFR CONDITIONS WITH SCATTERED CEILINGS.
WINDS WILL BE LIGHT AND VARIABLE TO A SE TO SW WIND AT 3 TO 8 MPH.
OVERNIGHT ISOLATED CONVECTION MAY DEVELOP OVER NORTHERN AR TO PARTS
OF CENTRAL AR AROUND SUNRISE FRIDAY...BUT DUE TO UNCERTAINTY IN
LOCATION AND COVERAGE...ONLY USED VCTS. VFR CEILINGS WILL BE SEEN
WITH CONVECTION. ON FRIDAY...ISOLATED CONVECTION WILL BE POSSIBLE
MAINLY OVER NE TO EAST AR AND ONLY USED VCTS DUE TO UNCERTAINTY.
WINDS ON FRIDAY WILL BE SE TO SW AT 5 TO 15 MPH...WHILE BECOMING
MORE W TO NW OVER NORTHERN AR DURING THE DAY. (59)
&&
.PREV DISCUSSION... /ISSUED 258 PM CDT THU AUG 6 2015/
.SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT
HOT AND HUMID CONDITIONS HAVE CONTINUED AROUND THE NATURAL STATE
TODAY WITH SHOWERS AND THUNDERSTORMS DEVELOPING ACROSS PORTIONS OF
CENTRAL ARKANSAS DURING THE DAY TODAY AND CONTINUING TO PUSH TO THE
SOUTHEAST THROUGH THE AFTERNOON. THERE ARE SOME SLIGHT CHANCES THAT
ADDITIONAL SHOWERS AND THUNDERSTORMS COULD DEVELOP THIS
AFTERNOON...GENERALLY SOUTH OF THE INTERSTATE 40 CORRIDOR. HRRR AND
WRF...HAVE CONTINUALLY SHOWED CHANCES FOR DEVELOPMENT THIS
AFTERNOON...BUT BASED ON CURRENT SATELLITE TRENDS...COULD NOT
JUSTIFY MORE THAN SLIGHT CHANCE POPS.
TONIGHT...EXPECT SHOWERS AND THUNDERSTORMS TO ONCE AGAIN DEVELOP
ACROSS NORTHWEST ARKANSAS IN RESPONSE TO AN UPPER LEVEL SHORTWAVE
THAT WILL PUSH SOUTHEAST...WITH BEST CHANCES NORTH OF THE INTERSTATE
40 WEST OF LITTLE ROCK TO NORTH OF INTERSTATE 530. THIS WILL ONCE
AGAIN KEEP TEMPERATURES SOMEWHAT LIMITED ACROSS NORTHERN ARKANSAS
AGAIN ON FRIDAY. HOWEVER...TEMPERATURES WILL WARM ALONG THE ARKANSAS
RIVER VALLEY AND TO THE SOUTHWEST ON FRIDAY WITH HEAT INDICES LIKELY
TOPPING 110 DEGREES. AS A RESULT...HAVE GONE AND ISSUED AN EXCESSIVE
HEAT WARNING ALONG THE ARKANSAS RIVER VALLEY.
UPPER LEVEL RIDGE WILL BUILD INTO THE REGION FOR THE WEEKEND AND
BRING EVEN HOTTER TEMPERATURES TO THE NATURAL STATE...WITH NO
PRECIPITATION EXPECTED. AT THIS POINT...FELT CONFIDENT IN EXTENDING
THE HEAT ADVISORY THROUGH SATURDAY...HOWEVER DID NOT EXTEND THE
EXCESSIVE HEAT WARNING. WILL LET FUTURE SHIFTS MONITOR THE THREAT.
&&
.LONG TERM...MONDAY THROUGH THURSDAY
UPPER AIR PATTERNS ACROSS NORTH AMERICA ARE EXPECTED TO UNDERGO
SUBTANTIAL AMPLIFICATION EARLY IN THIS PERIOD. A COLD FRONT WILL
MOVE SOUTH THROUGH THE MID SOUTH EARLY IN THIS PERIOD. AT THIS
TIME...PRECIPITATION AMOUNT SHOULD BE LIGHT. MAIN EFFECT OF THIS
FEATURE WILL BE TO BRING AN AIR MASS WITH NEAR NORMAL TEMPERATURES.
&&
.LZK WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY FROM NOON TO 7 PM CDT SATURDAY FOR BAXTER-BOONE-
INDEPENDENCE-JACKSON-MARION-NEWTON-SEARCY-STONE.
EXCESSIVE HEAT WARNING FROM NOON TO 7 PM CDT FRIDAY FOR BRADLEY-
CALHOUN-CLARK-CLEVELAND-CONWAY-DALLAS-DESHA-DREW-FAULKNER-
GARLAND-GRANT-HOT SPRING-JEFFERSON-JOHNSON-LINCOLN-LOGAN-LONOKE-
OUACHITA-PERRY-POPE-PULASKI-SALINE-YELL.
HEAT ADVISORY FROM NOON FRIDAY TO 7 PM CDT SATURDAY FOR ARKANSAS-
CLEBURNE-CONWAY-DESHA-FAULKNER-JEFFERSON-JOHNSON-LINCOLN-LOGAN-
LONOKE-MONROE-PERRY-POPE-PRAIRIE-PULASKI-SALINE-VAN BUREN-WHITE-
WOODRUFF-YELL.
HEAT ADVISORY UNTIL 7 PM CDT SATURDAY FOR BRADLEY-CALHOUN-CLARK-
CLEVELAND-DALLAS-DREW-GARLAND-GRANT-HOT SPRING-MONTGOMERY-
OUACHITA-PIKE-POLK-SCOTT.
&&
$$
AREA FORECAST DISCUSSION
NWS SACRAMENTO CA
307 PM PDT FRI AUG 7 2015
.SYNOPSIS...
DRIER WEATHER OVER THE WEEKEND WITH HIGH TEMPERATURES NEAR NORMAL.
MINOR COOLING NEXT WEEK WITH A SLIGHT CHANCE OF AFTERNOON THUNDERSTORMS
OVER THE NORTHERN MOUNTAINS TUESDAY INTO THURSDAY.
&&
.DISCUSSION...
UPPER LOW OVER THE SIERRA NEVADA WILL PUSH INTO THE GREAT BASIN
THIS EVENING AS UPSTREAM WEAK SHORT WAVE RIDGING BEGINS TO NUDGE
INLAND. HRRR SHOWING ISOLATED SHOWERS OR THUNDERSTORMS POSSIBLE
OVER THE HIGHER TERRAIN OF THE COASTAL RANGE BETWEEN WESTERN
SHASTA AND NORTH LAKE COUNTY, WESTERN PLUMAS, AND SIERRA NEVADA
UNTIL DARK. KSFO-KSAC SURFACE GRADIENT IS TRENDING UP WITH
MODERATE DELTA BREEZE, WHICH IS EXPECTED TO PERSIST OVERNIGHT,
PROVIDING COOLING INTO THE SOUTHERN SAC VALLEY. HAZE AND PATCHY
SMOKE POSSIBLE IN VICINITY OF WILDFIRES LATER TONIGHT AS BOUNDARY
LAYER STABILIZES.
WEAK UPPER RIDGING MOVES THROUGH EARLY SATURDAY. FLOW ALOFT TURNS
SOUTHWESTERLY OVER THE WEEKEND AND MONDAY AS A DEEP UPPER LOW
MOVES INTO THE NE PACIFIC AND ASSOCIATED TROUGHING EXTENDS
SOUTHWARD NEAR 130W. MODERATE ONSHORE FLOW WILL RESULT WITH NEAR
NORMAL HIGH TEMPERATURES.
&&
.EXTENDED DISCUSSION (TUESDAY THROUGH FRIDAY)
MODELS ARE CONTINUING TO SHOW DIFFERING SOLUTION WITH THE DEEP
UPPER LOW IN NE PAC EARLY NEXT WEEK. 18Z OPER GFS CONTINUES TO
SPLIT ENERGY AND DEVELOPS A SECONDARY LOW OFF THE NORCAL COAST
MONDAY AND SPINS AND DEEPENS THIS FEATURE THROUGH THE WEEK.
MEANWHILE THE 12Z EC CONTINUES TO KEEP THE ENERGY CONSOLIDATED,
DROPPING IT SLOWLY SOUTH ALONG 125W TO OFF THE NORCAL COAST
TUE/WED THEN PROGRESSING NE IT ACROSS THE PACNW THURSDAY. WITH
MODEL UNCERTAINTIES HAVE CONTINUED MENTION OF SLIGHT THREAT OF
AFTERNOON SHOWERS/THUNDERSTORMS OVER THE MOUNTAINS TUE/WED. HAVE
ADDED POPS TO THE NORTHERN MOUNTAINS AGAIN THURSDAY, AS EITHER
MODEL SOLUTION WOULD SUPPORT THIS. BELOW NORMAL TEMPERATURES
EXPECTED THROUGH THURSDAY WITH 80S TO MID 90S FOR THE CENTRAL
VALLEY AND 60S TO LOW 80S FOR THE MOUNTAINS AND FOOTHILLS.
PCH
&&
.AVIATION...
UPR LOW MOVS E INTO GRT BASIN THIS EVE, FLWD BY WK UPR RDG. VFR
CONDS NXT 24 HRS OVR INTR NORCAL EXC MVFR POSS IN ISOLD TSTM OVR
CSTL RNG AND HYR SIERNEV TIL 04Z. LCL SWLY SFC WND GSTS TO 30 KTS
POSS THRU DELTA TNGT.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 5 PM PDT THIS AFTERNOON FOR NORTHERN
MOTHERLODE FROM 1000 TO 3000 FT. INCLUDES PORTIONS OF NEVADA-
YUBA-PLACER-AMADOR AND ELDORADO UNITS-NORTHERN SIERRA INCLUDING
THE TAHOE AND ELDORADO NF/S WEST OF THE SIERRA CREST-SOUTHERN
MOTHERLODE FROM 1000 TO 3000 FT. INCLUDES PORTIONS OF CALAVERAS-
TUOLUMNE UNIT-STANISLAUS NF WEST OF THE SIERRA CREST.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS TAUNTON MA
1000 PM EDT SAT AUG 8 2015
.SYNOPSIS...
HIGH PRESSURE WILL MAINTAIN DRY WEATHER THROUGH SUN AS LOW
PRESSURE REMAINS WELL OFFSHORE...THOUGH A SPOT SHOWER IS POSSIBLE
ACROSS THE INTERIOR SUN AFTERNOON. LOW PRESSURE WILL RESULT IN
SCATTERED SHOWERS AND THUNDERSTORMS AT TIMES MON NIGHT INTO WED
MORNING. A TREND TOWARD DRIER WEATHER IS LIKELY THROUGH THE
REMAINDER OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
10 PM UPDATE...
LITTLE ADDITIONAL CHANGES NECESSARY WITH THIS UPDATE. IN SPITE OF
THE CLOUD COVER SEVERAL LOCATIONS ARE ALREADY MAKING A RUN INTO
THE MID 60S. DWPTS ACROSS THE REGION ARE AS LOW AS THE LOW-MID
50S SO THERE IS MORE ROOM TO DROP THROUGH THE OVERNIGHT HOURS.
THEREFORE...DID LOWER MINS BY A BIT...BUT THAT WAS THE ONLY REAL
CHANGE.
315 PM UPDATE...
PLENTY OF DIURNAL CU ACROSS INTERIOR WHERE HRRR AND 12Z NAM WANT
TO BRING SOME ISOLATED SHOWER ACTIVITY THIS AFTERNOON. COLUMN IS
FAIRLY DRY SO AM NOT BUYING INTO THAT...MODELS ARE MORE LIKELY
INDICATING BUILDING CU WHICH IS EVIDENT ON SATELLITE NEAR
BERKSHIRES.
MEANWHILE COASTAL LOW IS THROWING BACK SOME PATCHY MID AND HIGH
CLOUDS ALONG S COAST...CAPE COD AND ISLANDS. EXPECT THESE CLOUDS
TO THICKEN UP TONIGHT BUT NO RAIN EXPECTED AS BEST LIFT STAYS
OFFSHORE WITH PROGRESSIVE UPPER FLOW. SOME OF HIGH-RES MODELS
/HRRR...RAP AND ARW-WRF/ WANT TO BRING RAINFALL TO SE NEW ENGLAND
LATER TONIGHT BUT THAT LOOKS TO BE OVERDONE.
ANOTHER PLEASANTLY COOL NIGHT AHEAD WITH GOOD RADIATIONAL COOLING
CONDITIONS AWAY FROM INFLUENCE OF MID/HIGH CLOUDS NEAR S COAST.
LEANED TOWARD COOLER GFS LAMP GUIDANCE WHICH BRINGS LOWS INTO
UPPER 40S ACROSS NW MA AND MAINLY 50S ELSEWHERE.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
EXPECTING A GOOD AMOUNT OF CLOUDINESS NEAR CAPE COD AND ISLANDS
SUN DUE TO INCREASING NE FLOW ON PERIPHERY OF COASTAL LOW. MODEL
CROSS SECTIONS SHOW GOOD AMOUNT OF LOW LEVEL MOISTURE BELOW 950 MB
WHICH SHOULD BECOME TRAPPED. NO REAL MECHANISM FOR RAINFALL SO DRY
WEATHER ANTICIPATED AS DEEPER MOISTURE AND LIFT REMAIN WELL
OFFSHORE. SOME QUESTION AS TO WHETHER OR NOT LOW CLOUDS WILL BREAK
DURING AFTERNOON...BUT FOR NOW LEANED TOWARD THEM HANGING ON.
ACROSS INTERIOR...MODELS CONTINUE TO HINT AT POSSIBILITY OF FEW
SHOWERS BY AFTERNOON DUE TO SUBTLE LIFT FROM UPPER TROUGH. LOW
LEVEL CONVERGENCE IS MINIMAL DUE TO WEAK WIND FIELDS...SO ANY
ACTIVITY WOULD BE TIED TO TERRAIN. STABILITY PARAMETERS MARGINAL
SO EXPECT AN ISOLATED SHOWER OR PERHAPS A THUNDERSTORM ACROSS NW
AND POSSIBLY N CENTRAL MA.
HIGHS SHOULD BE A LITTLE COOLER THAN TODAY...ESPECIALLY NEAR COAST
DUE TO NE FLOW AND CLOUDINESS...RANGING FROM AROUND 70 ON OUTER
CAPE TO AROUND 80 FARTHER INLAND.
SUBSIDENCE AND SOME DRYING SUN NIGHT SHOULD LEAD TO AT LEAST
PARTIAL CLEARING...BUT CONTINUED ONSHORE FLOW MAY KEEP CLOUDS
LOCKED IN CLOSER TO COAST. LOWS SHOULD DROP BACK INTO 50S AND
LOWER 60S.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
HIGHLIGHTS...
* UNSETTLED WEATHER LIKELY LATE MON NIGHT THROUGH WED MORNING
* TEMPS SLIGHTLY BELOW NORMAL FOR MUCH OF THE WEEK
* POSSIBLE RETURN TO AUGUST HEAT FOR SATURDAY
OVERALL...MODELS ARE IN DECENT AGREEMENT THROUGH MUCH OF THE LONG
TERM. THERE ARE A COUPLE OF DISCREPANCIES THAT CONTINUE THROUGH THE
PERIOD. AS FAR AS SENSIBLE WEATHER GOES...THE MODELS ARE IN
AGREEMENT. LOOKING AT AN UPPER LEVEL TROUGH IN THE GREAT LAKES
MONDAY SLOWLY MOVING EASTWARD OVER THE NORTHEAST AND NEW ENGLAND BY
WEDNESDAY AND POTENTIALLY STALLING THERE THROUGH THE END OF THE
FORECAST PERIOD. THE ECMWF KEEPS THE PATTERN MORE AMPLIFIED...WHILE
THE GFS HAS A FLATTER FLOW AT THE MID-LEVELS WITH THE TROUGH
RETREATING INTO SOUTHEASTERN CANADA.
THIS TROUGH RESULTS IN LOW PRESSURE DEVELOPING IN THE GREAT LAKES
AND MOVING INTO QUEBEC TUESDAY. THE ECMWF PRODUCES A TRIPLE POINT
LOW OVER NEW JERSEY OFF THE MAIN LOW IN QUEBEC AND TRANSLATES THE
TRIPLE POINT LOW ALONG THE SOUTHERN NEW ENGLAND COAST. THE GFS
DEPICTS NO SUCH REDEVELOPMENT BUT KEEPS A STRONG SOUTHERLY FLOW
AHEAD OF THE COLD FRONT EXTENDING FROM THE QUEBEC LOW. THESE
DIFFERENCES COULD AFFECT THE OVERALL NATURE OF THE RAIN /WHETHER ITS
MORE STRATIFORM OR SHOWERY/ BUT REGARDLESS OF THE NATURE OR THE TYPE
OF SYSTEM...TUESDAY IS LIKELY TO BE WET. MODELS HINT THAT THE RAIN
COULD MOVE INTO OUR WESTERN ZONES LATE MONDAY NIGHT INTO EARLY
TUESDAY MORNING...BUT THE BULK OF THE RAIN APPEARS TO HOLD OFF TIL
AFTER 12Z TUESDAY. RAIN CONTINUES THROUGH TUESDAY INTO THE FIRST
PART OF THE DAY ON WEDNESDAY BUT THEN WILL TAPER OFF AS EITHER THE
FRONT MOVES THROUGH OR THE LOW PRESSURE EJECTS TOWARDS THE MARITIMES.
THE REMAINDER OF THE WEEK LOOKS TO BE DRY WITH A POSSIBILITY OF A
FEW DIURNAL SHOWERS HERE AND THERE EACH DAY. TEMPERATURES ARE
EXPECTED TO BE BELOW TO NEAR NORMAL UNTIL THE WEEKEND WHEN DEPENDING
ON THE MODEL COULD SEE A RETURN TO AUGUST HEAT AND HUMIDITY.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
00Z UPDATE...HIGH CONFIDENCE.
VFR TONIGHT WITH LIGHT N/NE WINDS. SHOULD SEE MVFR CIGS SPREAD
FROM OCEAN ONTO CAPE COD AND ISLANDS EARLY SUN MORNING. SOME
QUESTION AS TO WHETHER OR NOT CIGS SCT OUT OR LIFT TO VFR SUN
AFTERNOON. FOR NOW WE THINK CIGS WILL REMAIN MVFR THROUGH MUCH OF
DAY AND INTO SUN NIGHT. OTHERWISE VFR ELSEWHERE WITH BRIEF SHOWER
POSSIBLE ACROSS NW MA SUN AFTERNOON.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.
OUTLOOK /MONDAY THROUGH THURSDAY/...
MONDAY...HIGH CONFIDENCE. MAINLY VFR. LOW PROBABILITY OF MVFR/IFR
CIGS/VSBYS ENTERING WESTERN ZONES LATE MONDAY NIGHT WITH -RA.
TUESDAY...MODERATE CONFIDENCE. MVFR/IFR CONDITIONS LIKELY IN
WIDESPREAD RAIN/FOG.
WEDNESDAY...MODERATE CONFIDENCE. LINGERING MVFR/IFR CONDITIONS IN
DEPARTING RAIN. IMPROVING CONDITIONS THROUGH THE DAY.
THURSDAY...MODERATE CONFIDENCE. MAINLY VFR. LOW PROBABILITY OF
BRIEF MVFR CONDITIONS IN DIURNAL -SHRA.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
HIGH CONFIDENCE THROUGH SUN NIGHT.
DROPPED SCA ON OUTER S COASTAL WATERS WHERE SEAS HAVE SUBSIDED.
LIGHT N/NE WINDS GIVE WAY TO INCREASING NE WINDS SUN AND
ESPECIALLY SUN NIGHT...AS LOW PRESSURE PASSES WELL SE OF NEW
ENGLAND. SEAS SHOULD BEGIN TO BUILD LATER IN DAY AND COULD REACH 5
FT BY SUN NIGHT E AND S OF NANTUCKET...WHICH MAY REQUIRE SCA IN
LATER FORECASTS. DRY WEATHER EXPECTED THROUGH PERIOD.
OUTLOOK /MONDAY THROUGH THURSDAY/...
MONDAY...HIGH CONFIDENCE. WINDS AND SEAS DIMINISH AS HIGH PRESSURE
BUILDS OVER THE WATERS.
TUESDAY...MODERATE CONFIDENCE. WINDS AND SEAS INCREASE AS EITHER A
COLD FRONT OR A LOW PRESSURE SYSTEM MOVE OVER THE WATERS. SMALL
CRAFT ADVISORIES WILL LIKELY BE NEEDED FOR SEAS IF NOT WINDS AS
WELL. VISIBILITIES MAY BE LIMITED AT TIMES IN RAIN.
WEDNESDAY...MODERATE CONFIDENCE. WINDS AND SEAS DIMINISH AS LOW
PRESSURE PULLS AWAY FROM SOUTHERN NEW ENGLAND.
THURSDAY...MODERATE CONFIDENCE. QUIET BOATING WEATHER EXPECTED.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...RLG/JWD
NEAR TERM...DOODY/JWD
SHORT TERM...JWD
LONG TERM...RLG
AVIATION...RLG/JWD
MARINE...RLG/JWD
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
820 PM EDT SAT AUG 8 2015
.UPDATE...00Z TBW SOUNDING REVEALED LOWER PRECIPITABLE WATER
VALUE OF 1.86 INCHES COMPARED TO THE 2.04 INCHES AT 12Z. DRIER AIR
CONTINUES TO PUSH OVER THE AREA BEHIND THE CONVECTIVE COMPLEX
THAT MOVED SOUTHWARD OVER WEST- CENTRAL AND SOUTHWEST FLORIDA
THROUGHOUT TODAY DELIVERING PERIODS OF HEAVY RAINFALL AND FORCING
URBAN FLOODING IN SOME LOCATIONS ACROSS THE TAMPA BAY AREA.
LOWERED THE RAINFALL CHANCES THROUGH MUCH OF THE NIGHT AS THE
CONVECTION CONTINUES TO WEAKEN AND PUSH FARTHER SOUTH OVER THE
GULF. HRRR DATA SUGGESTS ISOLATED SHOWERS DEVELOPING ALONG THE
COAST EARLY SUNDAY MORNING HOWEVER WOULD EXPECT ANY DEVELOPMENT TO
BE LIMITED IN AREAL COVERAGE GIVEN THE DIMINISHING MOISTURE
PROFILES OVERSPREADING THE AREA.
WATER VAPOR SATELLITE IMAGERY DEPICTS A CLOSED LOW/VORT PACKAGE
NORTH OF THE CONUS OVER MANITOBA/ONTARIO MOVING EASTWARD. THIS
FEATURE WILL BE A MAJOR PLAYER IN THE EXTENDED FORECAST AS IT
CARVES OUT ANOTHER LONGWAVE TROUGH OVER THE EASTERN U.S. AS
RIDGING BUILDS OVER THE ROCKY MOUNTAINS AND SOUTHERN PLAINS MID-
LATE NEXT WEEK. THE NORTHWEST FLOW PATTERN WILL ENABLE SHORTWAVE
ENERGY TO PHASE WITH DEEPENING MOISTURE PROFILES TO ONCE AGAIN
INCREASE THE POTENTIAL FOR RAINFALL. 12Z ECMWF HAS COME A BIT MORE
IN LINE WITH THE GFS IN DEPICTING SURFACE LOW DEVELOPMENT ALONG
THE SW-NE SURFACE TROUGH OVER FLORIDA AND OFF THE SOUTHEAST U.S.
CLEARLY AN ACTIVE PATTERN FOR AWARENESS TO REMAIN HIGH GIVEN
RECENT AND ONGOING RIVER AND URBAN FLOODING IN MANY LOCATIONS
ACROSS THE GREATER TAMPA BAY REGION.
REISSUED AND EXTENDED THE HIGH RISK OF RIP CURRENTS THROUGH SUNDAY
EVENING GIVEN THE ONSHORE FLOW AND HIGH SURF EXPECTED. ONSHORE
FLOW PATTERN WILL WEAKEN LATER SUNDAY WITH IMPROVING SURF
CONDITIONS FOR A BRIEF PERIOD BEFORE ONSHORE FLOW AND UNSETTLED
WEATHER REDEVELOPS MID-LATE WEEK.
&&
.AVIATION...NO FLIGHT LIMITATIONS EXPECTED OVERNIGHT WITH VFR
CONDITIONS IN PLACE BEHIND THE AREA OF THUNDERSTORMS THAT PUSHED
SOUTHWARD OVER THE TERMINALS THIS AFTERNOON AND EVENING. SHRA/TSRA
CONTINUES TO WEAKEN AND PUSH SOUTH OF FMY/RSW THIS EVENING WITH
IMPROVING CIGS AND VSBYS TO VFR THROUGH THE NIGHT. ISOLATED AND
PATCHY GROUND FOG NOT OUT OF THE QUESTION OVERNIGHT AND INTO
SUNDAY MORNING GIVEN THE RECENT RAIN AND ALREADY SATURATED SOILS
AROUND THE TERMINAL LOCATIONS.
&&
.MARINE...WEAK PRESSURE GRADIENT RESIDES OVER THE AREA IN THE WAKE
OF THE THUNDERSTORM COMPLEX THAT PUSHED SOUTHWARD OVER THE WATERS
THROUGH MUCH OF TODAY. SHOWER AND THUNDERSTORM ACTIVITY HAS
DIMINISHED AND MOVED OUT OF THE SOUTHERN WATERS SOUTH OF SANIBEL
AND OFFSHORE NAPLES.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 80 92 78 91 / 20 40 50 40
FMY 77 92 77 91 / 30 40 50 50
GIF 76 94 76 93 / 20 50 50 40
SRQ 77 91 76 91 / 20 30 50 40
BKV 74 93 73 93 / 20 40 50 30
SPG 80 91 79 91 / 20 30 50 30
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...HIGH RIP CURRENT RISK UNTIL 8 PM EDT SUNDAY EVENING FOR
COASTAL CHARLOTTE-COASTAL HILLSBOROUGH-COASTAL LEE- COASTAL
MANATEE-COASTAL SARASOTA-PINELLAS.
GULF WATERS...NONE.
&&
$$
UPDATE/AVIATION/MARINE...10/LAMARRE
DECISION SUPPORT...09/RUDE
UPPER AIR/DATA COLLECTION...11/MCKAUGHAN
THERE IS NOT A LOT TO ADD FROM THE PREVIOUS FORECAST DISCUSSION. A
RATHER ANOMALOUS DEEP WESTERLY FLOW PATTERN IS IN PLACE BUT THE
MORNING SOUNDINGS SHOW AVERAGE DEEP MOISTURE AND LAPSE RATES.
HOWEVER...PRE FRONTAL MOISTURE IS HIGHER TO OUR NORTH AND THE FRONTAL
TROUGH WILL DROP SLOWLY THROUGH GEORGIA...SO AT LEAST OUR NORTHERN
HALF WILL SEE AROUND A QUARTER OF AN INCH INCREASE IN PRECIPITABLE
WATER. THIS IS ALREADY INDICATED BY SOME SHOWERS SPREADING WELL INLAND
FROM THE GULF.
THE EARLY MORNING HRRR AND LOCAL WRF MODELS SHOWED AFTERNOON
CONVECTION FORMING OVER NORTH FLORIDA AND ZIPPING EAST/SOUTHEAST...
MOVING OFFSHORE JUST TO OUR NORTH. WOULD EXPECT THAT SOME CELLS
COULD CLIP OUR NORTHERN SECTIONS OR SEND DOWN AN OUTFLOW BOUNDARY
THAT GENERATES NEW CONVECTION.
THE MESOSCALE MODELS ALSO SHOWED AN AREA OF CONVECTION DEVELOPING
ALONG THE SPACE/TREASURE COAST THIS AFTERNOON...PROBABLY AS WEST
COAST BOUNDARY MOVES ACROSS AND INTERACTS WITH THE LAKE OKEECHOBEE
BOUNDARY.
THE CURRENT AND PROGGED LOW LEVEL WINDS WILL BE STRONGER THAN NORMAL
WITH 925 MB WINDS AROUND 25 KNOTS ACROSS THE NORTH HALF.
THEREFORE...CELLS THIS AFTERNOON WILL PRODUCE STRONG WIND GUSTS AND
MARINERS WILL NEED TO BE PARTICULARLY AWARE OF THIS.
AN OVERALL SCATTERED COVERAGE SEEMS REASONABLE WITH THE HIGHEST
VALUES IN THE NORTH...SO NOT PLANNING MUCH CHANGE TO THE CURRENT
FORECAST.
&&
.AVIATION...
PRE FRONTAL MOISTENING WILL OCCUR ACROSS THE NORTH AND IS PROBABLY
ALREADY INDICATED BY SOME MORNING MVFR STRATUS THERE. EVEN THOUGH
THE EARLY MORNING MESOSCALE MODELS DID NOT PROJECT GULF SHOWERS TO
SPREAD INLAND...SOME ARE ALREADY APPROACHING THE NORTHERN
TERMINALS. WITH THE STRONGER THAN NORMAL WINDS IN THE LOWER LEVELS...
WIND GUSTS 30-40 KNOTS ARE EXPECTED MAINLY WITH THE AFTERNOON
SHOWERS/STORMS.
&&
.MARINE...(NO CHANGE TO PREVIOUS DISCUSSION)
TODAY...LOW LEVEL RIDGE AXIS HAS DROPPED BACK ACROSS SOUTH FL SO
THERE WILL BE A STRONGER OFFSHORE (W/SW) FLOW WITH WIND SPEEDS UP TO
15 KNOTS. IN ADDITION TO PRODUCING SOME CHOPPY SEAS OVER THE OPEN
ATLC...THE FASTER STORM MOTION WILL PRODUCE A THREAT FOR STRONG WIND
GUSTS AS THEY CROSS THE INTRACOASTAL AND ONTO THE NEARSHORE ATLC.
BOATERS SHOULD BE PREPARED FOR A COUPLE/FEW SPECIAL MARINE WARNINGS
THIS AFTN.
TONIGHT...EXPECT A CAUTION HEADLINE FOR THE OFFSHORE VOLUSIA AND
BREVARD WATERS FOR 15-20 KNOTS AS LOW PRESSURE PUSHES OFF THE
CAROLINA COAST AND PRES GRAD TIGHTENS.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
FORECASTS...LASCODY
IMPACT WX...SEDLOCK
AREA FORECAST DISCUSSION...UPDATED
NWS MELBOURNE FL
445 AM EDT FRI AUG 7 2015
.DISCUSSION...
TODAY...
A MID LEVEL SHORTWAVE TROUGH WILL PASS BY TO OUR NORTH AND INDUCE
SFC LOW DEVELOPMENT ALONG THE CAROLINA COAST. HIGHER MOISTURE
COMBINED WITH SOME MID LEVEL ENERGY WILL GENERATE SCATTERED TO
NUMEROUS STORMS ACROSS N FL. THE DEVELOPING NW FLOW ALOFT SHOULD
STEER SOME OF THESE STORMS AND THEIR OUTFLOWS INTO OUR NORTHERN
SECTIONS THIS AFTN. SO HAVE DRAWN HIGHER POPS (50 PERCENT) ACROSS
THE NORTH AND 20 PERCENT ACROSS THE FAR SOUTH. AT THE SFC...A BREEZY
W/SW FLOW IS EXPECTED WHICH WILL INHIBIT FORMATION OF THE EAST COAST
SEA BREEZE AND PRODUCE ABOVE NORMAL TEMPERATURES ESP AT THE COAST.
RECORD HIGHS APPEAR A BIT OUT OF REACH BUT WIDESPREAD MID 90S
EXPECTED.
TEMPS ALOFT ARE NOT VERY COOL (-6 TO -7C AT 500MB) BUT HOT SFC
TEMPS WILL HELP GROW INSTABILITY. AND LINGERING DRY AIR ALOFT
WILL COMBINE WITH THE STRONGER WIND FIELDS TO PRODUCE A RISK OF
STRONG WIND GUSTS WITH THE STORMS.
SAT-SUN...
WX PATTERN OVER THE ERN CONUS WILL BCM HIGHLY AMPLIFIED AS A 60-80KT
JET OVER W OF THE MS RIVER DIGS INTO THE MIDWEST AND COMBINES WITH A
DEPARTING 80-100KT JET S OF THE CANADIAN MARITIMES TO SPIN UP A
BROAD AREA OF LOW PRES OVER THE MID ATLC. WHILE THE RELATIVELY LOW
JET SPEEDS DO NOT IMPLY SIGNIFICANT DEEPENING AS THE LOW MOVES
INTO THE W ATLC...POST FRONTAL NWRLY FLOW WILL BE PROVIDED BY A
MID LVL ANTICYCLONE OVER THE TX PLAINS. COMBINED...THERE SHOULD BE
SUFFICIENT "PUSH AND PULL" TO CRANK A WEAK FRONTAL BOUNDARY FROM
THE MID SOUTH INTO N FL ON SAT...THEN INTO CENTRAL FL ON SUN.
OUTSIDE OF THE IMMEDIATE FRONTAL TROF...LATEST RAP ANALYSIS SHOWS
DEEP LYR MOISTURE OVER THE GOMEX/DEEP SOUTH IS SOMEWHAT
LACKING...ESP IN THE H100-H70 LYR. INDEED...WHILE MODEL SOUNDINGS
ARE INDICATING PREFRONTAL PWAT VALUES ON SAT BTWN 1.8"-2.0"...MUCH
OF THIS IS TRAPPED ABV THE H50 LVL. POST FRONTAL PWAT VALUES ON
SUN DROP TO 1.7"-1.8"...AGAIN MOSTLY ABV H50 WITH A NOTEWORTHY
AMOUNT OF DRY AIR IN THE H85-H50 LYR.
STRONG/SVR WX THREAT APPEARS MINIMAL FOR THE UPCOMING WEEKEND AS THE
APPROACHING FRONT PULLS A MID LVL THERMAL RIDGE FROM THE DEEP SOUTH
INTO THE FL PENINSULA. H70 TEMPS ARND 10C AND H50 TEMPS BTWN
-4/-5C...YIELDING AVG LAPSE RATES BTWN 5-6C/KM THRU THE LYR. MID LVL
DYNAMIC SUPPORT ON SAT WILL BE ENHANCED BY A TIGHT BAND OF VORTICITY
AS THE FRONT SAGS THROUGH N FL...THOUGH UPR LVL WINDS AOB 20KTS WILL
NOT GENERATE MUCH DIVERGENCE. VORTICITY DIMINISHES ON SUN AS THE
TROF AXIS WORKS ITS WAY INTO STATE...BUT UPR LVL DIVERGENCE SHOULD
INCREASE AS THE AMPLIFYING WX PATTERN ALLOWS 40-50KT WINDS TO WORK
THEIR WAY ACRS THE FL PENINSULA.
HIGHEST PRECIP CHANCES ON SAT AHEAD OF THE FRONT...60PCT OVER MOST
OF THE CWA...50PCT ARND LAKE OKEECHOBEE AS THE FRONT IS EXPECTED TO
STALL IN THE VICINITY OF THE I-4 CORRIDOR. PRECIP CHANCES DIMINISH
TO 40PCT AREAWIDE ON SUN DUE TO DRIER MID LVL AIR AND DIMINISHED MID
LVL DYNAMIC SUPPORT. PREVAILING WRLY FLOW ON SAT WILL PUSH MAX TEMPS
INTO THE L/M90S. SEA BREEZE FORMATION ON SUN WILL KEEP COASTAL
TEMPS IN THE U80S. MIN TEMPS IN THE L/M70S THRU THE WEEKEND.
MON-THU...
BOTH GFS/ECMWF MODELS INDICATE A STRONG MID LVL RIDGING PATTERN
PREVAILING OVER THE NATION`S MID SECTION INTO THE MIDDLE OF NEXT
WEEK. THIS WILL PROMOTE A PERSISTENT TROFFING PATTERN OVER THE ERN
CONUS WHICH IN TURN WILL PREVENT THE ATLC RIDGE AXIS FROM REBUILDING
ACRS THE FL PENINSULA. THE RESULTING WRLY STEERING FLOW WILL FAVOR
THE ERN FL PENINSULA FOR DAILY PRECIP.
NOTHING STANDING OUT THAT WOULD INDICATE HIGH PRECIP COVERAGE
ATTM...WILL KEEP POPS AOB 50PCT FOR NOW AS THE WEAKER FLOW REGIME
WILL ALLOW THE EAST COAST SEA BREEZE TO DVLP...WHILE THE RELATIVELY
LOW PRES OVER THE ERN SEABOARD WILL ALLOW SUFFICIENT MOISTURE TO
POOL ACRS THE REGION. TEMPERATURES CLOSE TO CLIMO WITH AFTN MAXES IN
THE U80S/L90S...MRNG MINS IN THE L/M70S.
&&
.AVIATION...
A STRONGER WESTERLY FLOW EXPECTED TODAY SO WILL NOT INDICATE A SEA
BREEZE AT COASTAL TERMINALS. SOME GUSTS NEAR 20 KNOTS CAN BE
EXPECTED DURING THE MID DAY NEAR PEAK HEATING. BEST CHANCE FOR
STORMS WILL BE OVER NORTHERN TERMINALS AND WILL PROBABLY ADD A
TEMPO GROUP FOR LEE/DAB IN THE NEXT TAF ISSUANCE...ROUGHLY 20Z-
22Z. WILL HOLD ONTO VCTS AT OTHER TERMINALS FOR NOW. FASTER CELL
MOTION WILL PROMOTE A RISK OF STRONG CONVECTIVE WIND GUSTS IN AND
NEAR STORMS.
&&
.MARINE...
TODAY...LOW LEVEL RIDGE AXIS HAS DROPPED BACK ACROSS SOUTH FL SO
THERE WILL BE A STRONGER OFFSHORE (W/SW) FLOW WITH WIND SPEEDS UP
TO 15 KNOTS. IN ADDITION TO PRODUCING SOME CHOPPY SEAS OVER THE
OPEN ATLC...THE FASTER STORM MOTION WILL PRODUCE A THREAT FOR
STRONG WIND GUSTS AS THEY CROSS THE INTRACOASTAL AND ONTO THE
NEARSHORE ATLC. BOATERS SHOULD BE PREPARED FOR A COUPLE/FEW
SPECIAL MARINE WARNINGS THIS AFTN.
TONIGHT...EXPECT A CAUTION HEADLINE FOR THE OFFSHORE VOLUSIA AND
BREVARD WATERS FOR 15-20 KNOTS AS LOW PRESSURE PUSHES OFF THE
CAROLINA COAST AND PRES GRAD TIGHTENS.
SAT-SAT NIGHT...GENTLE TO MODERATE W/SW BREEZE WILL PREVAIL AS A
BROAD LOW PRES SYSTEM OVER THE MID ATLC CRANKS A FRONTAL BOUNDARY
INTO N FL. THE WRLY COMPONENT WILL GENERATE SHORT PD WIND CHOP
INCREASING SEAWARD... 1-2FT NEARSHORE AND 2-3FT OFFSHORE...UP TO 4FT
IN THE GULF STREAM. SCT/NMRS OFFSHORE MOVING SHRAS AND TSTMS.
SUN-SUN NIGHT...LCL PGRAD WILL SLACKEN AS THE FRONTAL BNDRY SAGS
INTO CENTRAL FL. LIGHT TO GENTLE WRLY BREEZE BCMG S/SE NEAR THE
COAST IN THE AFTN WITH THE FORMATION OF THE EAST COAST SEA BREEZE...
THEN A LIGHT SRLY BREEZE OVERNIGHT AS THE FRONT WASHES OUT OVER S
FL. SEAS AOB 2FT NEARSHORE AND 2-3FT OFFSHORE. SCT SHRAS/ISOLD TSRAS
MOVING ONSHORE.
MON-MON NIGHT...WEAK PGRAD WILL PERSIST IN THE WAKE OF THE
DISSIPATED FRONT. LIGHT ERLY BREEZE THRU THE DAY...BCMG A LIGHT
TO GENTLE S/SE BREEZE OVERNIGHT AS A NEW STORM SYSTEM PULLS
ANOTHER FRONTAL BOUNDARY INTO THE DEEP SOUTH. SEAS AOB 2FT
NEARSHORE AND 2-3FT OFFSHORE.
TUE-TUE NIGHT...LIGHT TO GENTLE S/SERLY BREEZE THRU THE DAY BCMG A
GENTLE TO MODERATE S/SWRLY BREEZE OVERNIGHT AS THE FRONTAL TROF SAGS
INTO N FL AND STALLS. LIMITED FETCH WILL KEEP NEARSHORE SEAS AOB
2FT...OFFSHORE SEAS 2-3FT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 91 76 89 75 / 50 30 60 20
MCO 92 76 92 76 / 30 20 60 20
MLB 94 75 92 76 / 30 20 60 20
VRB 94 75 92 74 / 30 20 60 20
LEE 90 77 91 77 / 40 30 60 20
SFB 92 77 91 76 / 40 20 60 20
ORL 92 78 92 77 / 30 20 60 20
FPR 94 73 92 75 / 30 20 50 20
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM...KELLY
LONG TERM....BRAGAW
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
433 AM EDT FRI AUG 7 2015
.DISCUSSION...
TODAY...A MID LEVEL SHORTWAVE TROUGH WILL PASS BY TO OUR NORTH
AND INDUCE SFC LOW DEVELOPMENT ALONG THE CAROLINA COAST. HIGHER
MOISTURE COMBINED WITH SOME MID LEVEL ENERGY WILL GENERATE
SCATTERED TO NUMEROUS STORMS ACROSS N FL. THE DEVELOPING NW FLOW
ALOFT SHOULD STEER SOME OF THESE STORMS AND THEIR OUTFLOWS INTO
OUR NORTHERN SECTIONS THIS AFTN. SO HAVE DRAWN HIGHER POPS (50
PERCENT) ACROSS THE NORTH AND 20 PERCENT ACROSS THE FAR SOUTH. AT
THE SFC...A BREEZY W/SW FLOW IS EXPECTED WHICH WILL INHIBIT
FORMATION OF THE EAST COAST SEA BREEZE AND PRODUCE ABOVE NORMAL
TEMPERATURES ESP AT THE COAST. RECORD HIGHS APPEAR A BIT OUT OF
REACH BUT WIDESPREAD MID 90S EXPECTED.
TEMPS ALOFT ARE NOT VERY COOL (-6 TO -7C AT 500MB) BUT HOT SFC
TEMPS WILL HELP GROW INSTABILITY. AND LINGERING DRY AIR ALOFT
WILL COMBINE WITH THE STRONGER WIND FIELDS TO PRODUCE A RISK OF
STRONG WIND GUSTS WITH THE STORMS.
SAT-SUN...
WX PATTERN OVER THE ERN CONUS WILL BCM HIGHLY AMPLIFIED AS A 60-80KT
JET OVER W OF THE MS RIVER DIGS INTO THE MIDWEST AND COMBINES WITH A
DEPARTING 80-100KT JET S OF THE CANADIAN MARITIMES TO SPIN UP A
BROAD AREA OF LOW PRES OVER THE MID ATLC. WHILE THE RELATIVELY LOW
JET SPEEDS DO NOT IMPLY SIGNIFICANT DEEPENING AS THE LOW MOVES
INTO THE W ATLC...POST FRONTAL NWRLY FLOW WILL BE PROVIDED BY A
MID LVL ANTICYCLONE OVER THE TX PLAINS. COMBINED...THERE SHOULD BE
SUFFICIENT "PUSH AND PULL" TO CRANK A WEAK FRONTAL BOUNDARY FROM
THE MID SOUTH INTO N FL ON SAT...THEN INTO CENTRAL FL ON SUN.
OUTSIDE OF THE IMMEDIATE FRONTAL TROF...LATEST RAP ANALYSIS SHOWS
DEEP LYR MOISTURE OVER THE GOMEX/DEEP SOUTH IS SOMEWHAT
LACKING...ESP IN THE H100-H70 LYR. INDEED...WHILE MODEL SOUNDINGS
ARE INDICATING PREFRONTAL PWAT VALUES ON SAT BTWN 1.8"-2.0"...MUCH
OF THIS IS TRAPPED ABV THE H50 LVL. POST FRONTAL PWAT VALUES ON
SUN DROP TO 1.7"-1.8"...AGAIN MOSTLY ABV H50 WITH A NOTEWORTHY
AMOUNT OF DRY AIR IN THE H85-H50 LYR.
STRONG/SVR WX THREAT APPEARS MINIMAL FOR THE UPCOMING WEEKEND AS THE
APPROACHING FRONT PULLS A MID LVL THERMAL RIDGE FROM THE DEEP SOUTH
INTO THE FL PENINSULA. H70 TEMPS ARND 10C AND H50 TEMPS BTWN
-4/-5C...YIELDING AVG LAPSE RATES BTWN 5-6C/KM THRU THE LYR. MID LVL
DYNAMIC SUPPORT ON SAT WILL BE ENHANCED BY A TIGHT BAND OF VORTICITY
AS THE FRONT SAGS THROUGH N FL...THOUGH UPR LVL WINDS AOB 20KTS WILL
NOT GENERATE MUCH DIVERGENCE. VORTICITY DIMINISHES ON SUN AS THE
TROF AXIS WORKS ITS WAY INTO STATE...BUT UPR LVL DIVERGENCE SHOULD
INCREASE AS THE AMPLIFYING WX PATTERN ALLOWS 40-50KT WINDS TO WORK
THEIR WAY ACRS THE FL PENINSULA.
HIGHEST PRECIP CHANCES ON SAT AHEAD OF THE FRONT...60PCT OVER MOST
OF THE CWA...50PCT ARND LAKE OKEECHOBEE AS THE FRONT IS EXPECTED TO
STALL IN THE VICINITY OF THE I-4 CORRIDOR. PRECIP CHANCES DIMINISH
TO 40PCT AREAWIDE ON SUN DUE TO DRIER MID LVL AIR AND DIMINISHED MID
LVL DYNAMIC SUPPORT. PREVAILING WRLY FLOW ON SAT WILL PUSH MAX TEMPS
INTO THE L/M90S. SEA BREEZE FORMATION ON SUN WILL KEEP COASTAL
TEMPS IN THE U80S. MIN TEMPS IN THE L/M70S THRU THE WEEKEND.
MON-THU...UPDATE TO FOLLOW.
&&
.AVIATION...
A STRONGER WESTERLY FLOW EXPECTED TODAY SO WILL NOT INDICATE A SEA
BREEZE AT COASTAL TERMINALS. SOME GUSTS NEAR 20 KNOTS CAN BE
EXPECTED DURING THE MID DAY NEAR PEAK HEATING. BEST CHANCE FOR
STORMS WILL BE OVER NORTHERN TERMINALS AND WILL PROBABLY ADD A
TEMPO GROUP FOR LEE/DAB IN THE NEXT TAF ISSUANCE...ROUGHLY 20Z-
22Z. WILL HOLD ONTO VCTS AT OTHER TERMINALS FOR NOW. FASTER CELL
MOTION WILL PROMOTE A RISK OF STRONG CONVECTIVE WIND GUSTS IN AND
NEAR STORMS.
&&
.MARINE...
TODAY...LOW LEVEL RIDGE AXIS HAS DROPPED BACK ACROSS SOUTH FL SO
THERE WILL BE A STRONGER OFFSHORE (W/SW) FLOW WITH WIND SPEEDS UP
TO 15 KNOTS. IN ADDITION TO PRODUCING SOME CHOPPY SEAS OVER THE
OPEN ATLC...THE FASTER STORM MOTION WILL PRODUCE A THREAT FOR
STRONG WIND GUSTS AS THEY CROSS THE INTRACOASTAL AND ONTO THE
NEARSHORE ATLC. BOATERS SHOULD BE PREPARED FOR A COUPLE/FEW
SPECIAL MARINE WARNINGS THIS AFTN.
TONIGHT...EXPECT A CAUTION HEADLINE FOR THE OFFSHORE VOLUSIA AND
BREVARD WATERS FOR 15-20 KNOTS AS LOW PRESSURE PUSHES OFF THE
CAROLINA COAST AND PRES GRAD TIGHTENS.
SAT-SAT NIGHT...GENTLE TO MODERATE W/SW BREEZE WILL PREVAIL AS A
BROAD LOW PRES SYSTEM OVER THE MID ATLC CRANKS A FRONTAL BOUNDARY
INTO N FL. THE WRLY COMPONENT WILL GENERATE SHORT PD WIND CHOP
INCREASING SEAWARD... 1-2FT NEARSHORE AND 2-3FT OFFSHORE...UP TO 4FT
IN THE GULF STREAM. SCT/NMRS OFFSHORE MOVING SHRAS AND TSTMS.
SUN-SUN NIGHT...LCL PGRAD WILL SLACKEN AS THE FRONTAL BNDRY SAGS
INTO CENTRAL FL. LIGHT TO GENTLE WRLY BREEZE BCMG S/SE NEAR THE
COAST IN THE AFTN WITH THE FORMATION OF THE EAST COAST SEA BREEZE...
THEN A LIGHT SRLY BREEZE OVERNIGHT AS THE FRONT WASHES OUT OVER S
FL. SEAS AOB 2FT NEARSHORE AND 2-3FT OFFSHORE. SCT SHRAS/ISOLD TSRAS
MOVING ONSHORE.
MON-MON NIGHT...WEAK PGRAD WILL PERSIST IN THE WAKE OF THE
DISSIPATED FRONT. LIGHT ERLY BREEZE THRU THE DAY...BCMG A LIGHT
TO GENTLE S/SE BREEZE OVERNIGHT AS A NEW STORM SYSTEM PULLS
ANOTHER FRONTAL BOUNDARY INTO THE DEEP SOUTH. SEAS AOB 2FT
NEARSHORE AND 2-3FT OFFSHORE.
TUE-TUE NIGHT...LIGHT TO GENTLE S/SERLY BREEZE THRU THE DAY BCMG A
GENTLE TO MODERATE S/SWRLY BREEZE OVERNIGHT AS THE FRONTAL TROF SAGS
INTO N FL AND STALLS. LIMITED FETCH WILL KEEP NEARSHORE SEAS AOB
2FT...OFFSHORE SEAS 2-3FT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 91 76 89 75 / 50 30 60 20
MCO 92 76 92 76 / 30 20 60 20
MLB 94 75 92 76 / 30 20 60 20
VRB 94 75 92 74 / 30 20 60 20
LEE 90 77 91 77 / 40 30 60 20
SFB 92 77 91 76 / 40 20 60 20
ORL 92 78 92 77 / 30 20 60 20
FPR 94 73 92 75 / 30 20 50 20
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM...KELLY
LONG TERM....BRAGAW
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
633 AM EDT FRI AUG 7 2015
.SYNOPSIS...
AN UPPER TROUGH AND ASSOCIATED FRONTAL BOUNDARY WILL MOVE EAST OF
THE FORECAST AREA BY TONIGHT. DRIER AIR WILL RETURN FOR THE
WEEKEND. ANOTHER FRONT MAY AFFECT THE REGION BY THE MIDDLE OF NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SCATTERED SHOWERS CONTINUE OVER PORTIONS OF THE EASTERN AND
SOUTHERN MIDLANDS THIS MORNING AHEAD OF SHORT WAVE ENERGY IN THE
WESTERN CAROLINAS. LATEST HRRR INDICATING THAT MOST OF THE
PRECIPITATION WILL END BY AROUND 13Z...ALTHOUGH SOME LATER
DEVELOPMENT WILL BE POSSIBLE ESPECIALLY DURING THE AFTERNOON AS A
FRONTAL BOUNDARY PUSHES THROUGH THE AREA. HOWEVER...WITH THE SHORT
WAVE ENERGY MOVING EASTWARD...THE BEST CHANCE FOR PRECIPITATION
WILL BE MAINLY THIS MORNING. AFTERNOON HIGH TEMPERATURES WILL BE
GENERALLY IN THE UPPER 80S NORTH TO AROUND 90 DEGREES ELSEWHERE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
DRIER ATMOSPHERE FOR SATURDAY AS WEAK HIGH PRESSURE BUILDS IN FROM
THE WEST. WEAK COOL ADVECTION BEHIND THE FRONT AND DEPARTING LOW
EXPECTED TO KEEP TEMPS DOWN TO NEAR CLIMATOLOGY SATURDAY.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
NO CHANGES TO THE EXTENDED FORECAST AT THIS TIME. MODELS INDICATE
UPPER RIDGE WILL SHIFT BACK TO THE WEST SOME...WITH UPPER TROUGH
DEEPENING OVER THE E CONUS...EARLY TO MID NEXT WEEK. THIS ALONG
WITH SOME EXPECTED INCREASE IN MOISTURE AND INDICATIONS OF A
POSSIBLE FRONT SUGGESTS TREND TOWARDS INCREASING POPS. GENERALLY
ACCEPTED BLEND OF GUIDANCE.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
UPPER TROUGH AXIS IS CROSSING THE AREA THIS MORNING AND THE SHOWERS
ASSOCIATED WITH IT ARE SHIFTING NORTH AND EAST OF THE TERMINALS.
WIDESPREAD MVFR CIGS ASSOCIATED WITH THE PASSING UPPER TROUGH WILL
LINGER THROUGH MID MORNING BEFORE VFR CIGS RETURN BY 15Z. ISOLATED
TO SCATTERED SHOWERS AND AN ISOLATED THUNDERSTORM POSSIBLE TODAY BUT
CONFIDENCE IS LOW AS DRIER AIR MOVES IN FROM THE WEST AND THEREFORE
NO MENTION OF STORMS IN THE FORECAST. WINDS WILL PICK UP FROM THE
WEST AROUND 10 KNOTS AFTER 15Z THEN A WEAK COLD FRONT WILL CROSS THE
REGION AND WINDS WILL SHIFT TO THE NORTHWEST.
EXTENDED AVIATION OUTLOOK...NO WIDESPREAD RESTRICTIONS TO
AVIATION EXPECTED THROUGH MONDAY. SHOWERS AND THUNDERSTORMS
POSSIBLE TUESDAY AS A COLD FRONT CROSSES THE REGION.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
99
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1002 PM CDT SAT AUG 8 2015
.SHORT TERM...
320 PM CDT
THROUGH SUNDAY...
MAIN CONCERN IS WITH CONVECTIVE POTENTIAL LATE TONIGHT INTO
SUNDAY. RAOBS AND AIRCRAFT SOUNDINGS TODAY SHOWED AN ENVIRONMENT
HOSTILE TO PRECIP MAINTENANCE. THEREFORE DESPITE SOME FORCING FROM
A CONVECTIVELY INDUCED SHORTWAVE OVERHEAD...LIGHT RADAR ECHOES
OVER AREA ARE LIKELY VIRGA AND HAVE PULLED MENTION OF SPRINKLES
THE REST OF TODAY. CONVERGENT AXIS IN FRONTAL ZONE OF DISSIPATING
WEAK LOW OVER SOUTHERN LAKE MICHIGAN DID INITIATIVE SOME
CONVECTION OVER NORTH CENTRAL INDIANA...AND WOULD EXPECT FURTHER
DEVELOPMENT TO REMAIN EAST OF THE CWA. OVERALL...WITH PLENTY OF
CLOUD COVER WELL BACK TO THE WEST...INCLUDING PATCHY LOWER CLOUDS
IN SPOTS...JUST EXPECTING A MOSTLY CLOUDY REST OF THE DAY INTO
TONIGHT. VERY WEAK GRADIENT WILL YIELD LIGHT/CALM WINDS OVERNIGHT
AND LOW DEWPOINT SPREADS COULD SET STAGE FOR SOME PATCHY FOG OR
HAZE. LOW TEMPS WILL BE IN THE MID 60S TO AROUND 70.
FOCUS LATE TONIGHT INTO SUNDAY WILL BE ON MCS EXPECTED TO DEVELOP
OVER EASTERN NEBRASKA AND WESTERN IOWA THIS EVENING. MCS IS LIKELY
TO RIDE ALONG INSTABILITY AXIS THAT WILL MAINLY BE SOUTH OF THE
CWA OFF TO THE EAST-SOUTHEAST INTO SUNDAY MORNING. CONSENSUS OF
MODEL GUIDANCE IS TO KEEP INSTABILITY MINIMAL AT BEST FOR MUCH OF
THE CWA...LIMITING THUNDER POTENTIAL. CANNOT COMPLETELY RULE OUT
THUNDER GIVEN MODEST LOW LEVEL JET/WAA REGIME. RECENT HI-RES
CAMS...INCLUDING 4KM NAM AND EXPERIMENTAL HRRR DEPICT A REASONABLE
SCENARIO IN WHICH STRATIFORM NORTH OF MCS OVERSPREADS MUCH OF CWA
FROM WESTNORTHWEST TO EAST SOUTHEAST AFTER MIDNIGHT THROUGH MID
SUNDAY MORNING/BY WHICH TIME IT WILL PROBABLY BE DECAYING. HAVE
FOCUSED CATEGORICAL POPS INTO SOUTHERN CWA WHERE CONFIDENCE IS
HIGHEST IN WIDESPREAD COVERAGE. ITS POSSIBLE FAR NORTHEAST CWA
COULD SEE LITTLE OR NO RAIN. BEST CHANCE FOR HEAVY DOWNPOURS LOOKS
TO BE IN FAR SOUTHERN CWA WHERE MORE ROBUST CONVECTION COULD PASS
THROUGH...THOUGH ANY THREAT FOR STRONG TO SEVERE STORMS SHOULD
STAY SOUTHWEST OF THE CWA GIVEN ANTICIPATED DECAYING TREND OF MCS.
A GOOD DEAL OF UNCERTAINTY THE REMAINDER OF SUNDAY REGARDING
CONVECTIVE TRENDS. A SURFACE LOW LOOKS TO EVOLVE EASTWARD INTO THE
MID MISSISSIPPI VALLEY BY LATER IN THE DAY...WITH RETURN FLOW AND
WEST-SOUTHWEST LLJ ALSO DEVELOPING. LINGERING CLOUD COVER WILL
LIMIT DESTABILIZATION AND THUNDER POTENTIAL...ESPECIALLY FARTHER
NORTH UNTIL LATE DAY. ANOTHER SHORTWAVE WILL APPROACH FROM WEST IN
LATE AFTERNOON AND THERE SHOULD BE ENOUGH 925-850 MB MOISTURE
CONVERGENCE TO SUPPORT CHANCE POPS NORTH OF I-80 AND LIKELIESSOUTH
OF I-80. MODERATE WESTERLY MIDLEVEL FLOW WILL RESULT IN 30-40 KT
OF WEST-NORTHWEST 0-6KM SHEAR. THIS WILL SUPPORT SOME THREAT FOR
STRONG TO SEVERE STORMS WELL SOUTH OF I-80 CLOSER TO EXPECTED
TRACK OF SFC LOW AND WHERE TEMPS AROUND 80 AND LOW-MID 70S
DEWPOINTS COULD BRING SLIGHTLY BETTER INSTABILITY. MAIN THREAT
WOULD BE GUSTY TO DAMAGING WINDS...AS HAIL APPEARS UNLIKELY WITH
700-500 MB LAPSE RATES LESS THAN 6 CELSIUS PER KM. SUNDAY OVERALL
WILL BE A CLOUDY AND MUGGY DAY...WITH HIGHS IN THE MID 70S TO
AROUND 80.
RC
&&
.LONG TERM...
320 PM CDT
SUNDAY NIGHT THROUGH SATURDAY...
THE BEST CHANCE FOR PRECIP IN THE EXTENDED WILL BE SUNDAY EVENING
THROUGH MONDAY AFTERNOON...WITH VERY SLIGHT CHANCES OF PRECIP LATE
NEXT WEEK.
A COMPLEX OF STORMS WILL BE DIMINISHING OVER THE REGION SUNDAY
EVENING AND NIGHT. THE UPPER LEVEL VORTICITY PATTERN IS VERY CHAOTIC
WITH GUIDANCE INDICATING THE MAIN MCV WILL BE OVER CENTRAL IL AND
VORT STREAMERS ASSOCIATED WITH THE UPPER LEVEL TROUGH WILL BE OVER
WISCONSIN. WITH SUCH A MESSY PATTERN...DECIDED TO ONLY MAKE MINOR
ADJUSTMENTS TO PRECIP CHANCES SUNDAY NIGHT. HAVE A CHANCE OF
THUNDERSTORMS ALONG AND EAST OF I-39 WITH BETTER CHANCES EAST OF I-
55. COULD SEE A FEW STRONG TO SEVERE STORMS SOUTH OF I-80 BUT
CONDITIONS WILL BE WEAKENING AS THE EVENING PROGRESSES.
OVERALL...HAVE LOW CONFIDENCE IN EXACTLY HOW SUNDAY NIGHT WILL PLAY
OUT DUE TO SO MANY MESOSCALE FEATURES AND WHETHER OR NOT THE
ATMOSPHERE WILL BE ABLE TO RECOVER FROM SUNDAY MORNING/S STORMS.
A SHORT WAVE MOVING WITH THE UPPER LEVEL TROUGH ROTATES THROUGH
MONDAY WITH A DECENT VORTICITY STREAMER. WENT WITH A CHANCE OF
SHOWERS AND STORMS MAINLY NORTH OF I-80 MONDAY. THINKING THE NAM IS
ONCE AGAIN TOO MOIST LEADING TO TOO MUCH CONVECTIVE DEVELOPMENT.
THINKING SHOWERS AND STORMS WILL DRIFT SOUTH OF THE IL/WI STATE LINE
MONDAY AFTERNOON AND THEN WEAKEN AS THEY CONTINUE TO SHIFT SOUTH
MONDAY EVENING. MONDAY EVENING MAY END UP BEING DRY...BUT DID NOT
HAVE ENOUGH CONFIDENCE IN A DRY FORECAST SO KEPT A SLIGHT CHANCE OF
SHOWERS AND STORMS ALONG AND SOUTH OF I-80 MONDAY EVENING.
THE UPPER LEVEL TROUGH AXIS SHIFTS EAST THROUGH WISCONSIN WITH
COOLER UPPER LEVEL AIR SINKING SOUTH THROUGH THE REGION. HIGH
PRESSURE THEN BUILDS IN FOR WEDNESDAY AND THURSDAY LEADING TO DRY
CONDITIONS THROUGH THURSDAY. HIGH TEMPS TUESDAY WILL BE AROUND
80...THEN IN THE UPPER 70S WEDNESDAY. LAKE BREEZES BOTH DAYS WILL
KEEP LOCATIONS ALONG THE LAKE IN THE MID 70S. TEMPS REBOUND INTO
THE LOW TO MID 80S THURSDAY WITH NO LAKE COOLING.
THE NEXT LOW PRESSURE SYSTEM MOVES OVER JAMES BAY THURSDAY EVENING
AND PUSHES THE HIGH PRESSURE SOUTH OVER THE OHIO VALLEY. THE LOWS
COLD FRONT SINKS SOUTH OVER FAR NORTHERN IL FRIDAY AFTERNOON SO HAVE
A SLIGHT CHANCE TO CHANCE OF SHOWERS AND STORMS.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* LIGHT NORTHEAST WINDS BECOMING VARIABLE OVERNIGHT.
* PERIOD OF RAIN LIKELY SUNDAY MORNING...POSSIBLY WITH MVFR
CIGS/VIS.
* CHANCE OF SHOWERS AGAIN LATER IN THE DAY...ISOLATED THUNDER
POSSIBLE BUT MORE LIKELY SOUTH OF TERMINALS.
RATZER
//DISCUSSION...UPDATED 00Z...
WEAK SFC LOW PRESSURE EAST OF AREA ALONG MI/IN BORDER EARLY THIS
EVENING...WITH WEAK HIGH PRESSURE OVER WI/NORTHERN IL AND THE
LAKE. WINDS HAVE SHIFTED TO THE NORTHEAST ACROSS THE AREA AS THE
LOW DEPARTS...AND WHILE SOME GUSTS IN THE 15 KT RANGE HAVE BEEN
NOTED AS THE WIND SHIFT PUSHES DOWN THE LAKE SHORE...WINDS INLAND
ARE EXPECTED TO REMAIN 10 KTS OR LESS THIS EVENING.
LACK OF STRONG DRYING MAY ALLOW FOR DEVELOPMENT OF PATCHY MVFR
CIGS OR 4-5SM HAZE/FOG LATE TONIGHT...THOUGH EXTENSIVE CLOUD COVER
WILL NOT LIKELY SUPPORT WIDESPREAD VISIBILITY REDUCTION BELOW
MVFR. ATTENTION THEN TURNS TO A MID-LEVEL DISTURBANCE APPROACHING
FROM THE PLAINS EARLY SUNDAY MORNING...WITH AN ATTENDANT
THUNDERSTORM COMPLEX CURRENTLY TAKING SHAPE FROM KS INTO IA.
HIGH-RES MODELS DEPICT THIS COMPLEX MOVING INTO IL EARLY SUNDAY
MORNING...THOUGH WITH THE GREATEST POTENTIAL FOR THUNDER MAINLY
SOUTH OF THE TERMINALS ALONG WARM FRONT. MORNING RAIN/CLOUD COVER
WILL ALSO LIKELY SUPPRESS THE WARM FRONT AND GREATER INSTABILITY
SOUTH OF THE TERMINALS WITH LITTLE FOCUS FOR ORGANIZED
THUNDERSTORM DEVELOPMENT IN THE IMMEDIATE VICINITY. HIGH-RES
MODELS THEN DEPICT ANOTHER CLUSTER OF THUNDERSTORMS PASSING SOUTH
OF THE TERMINALS SUNDAY EVENING.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* HIGH IN WINDS AND OTHER ELEMENTS THIS EVENING.
* MEDIUM IN RAIN COVERAGE/TIMING AND MVFR POTENTIAL SUNDAY
MORNING.
* MEDIUM-LOW IN WINDS SUNDAY...THOUGH SHOULD BE GENERALLY LESS
THAN 10 KTS.
* LOW IN SHRA/ISOLATED TSRA COVERAGE SUNDAY AFTERNOON/EVE.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...
MONDAY...CHANCE OF SHRA/TSRA AND MVFR. NORTH-NORTHEAST WINDS.
TUESDAY AND WEDNESDAY...VFR. NORTHEAST WINDS.
THURSDAY...VFR. WEST-SOUTHWEST WINDS.
FRIDAY...SLIGHT CHANCE TSRA. WEST-SOUTHWEST WINDS.
RATZER
&&
.MARINE...
320 PM CDT
HIGH PRESSURE STRETCHES FROM QUEBEC THROUGH THE OHIO VALLEY WHILE
LOW PRESSURE IS OVER MANITOBA. BOTH SYSTEMS WILL SHIFT EAST WITH THE
LOW REACHING JAMES BAY BY MONDAY MORNING. AS SUCH LIGHT NORTHEAST
WINDS BECOME SOUTH TO SOUTHEAST SUNDAY. THE TROUGH ASSOCIATED WITH
THE LOWS COLD/STATIONARY FRONT SHIFTS THROUGH LATE SUNDAY NIGHT INTO
MONDAY MORNING WITH WINDS BECOMING NORTH BEHIND IT. A WEAK CLOSED
LOW FORMS OVER THE EASTERN GREAT LAKES MONDAY EVENING AND DEEPENS AS
IT SHIFTS NORTHEAST. AT THE SAME TIME HIGH PRESSURE WILL BE PUSHING
EAST OVER THE WESTERN GREAT LAKES. THIS WILL LEAD TO NORTH WINDS
INCREASING TO 10 TO 20 KT MONDAY NIGHT THROUGH TUESDAY NIGHT. WINDS
WEAKEN WEDNESDAY WITH THE HIGH OVERHEAD...AND THEN BACK TO SOUTHWEST
AS THE HIGH IS PUSHED SOUTH BY THE NEXT LOW OVER JAMES BAY THURSDAY.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS LINCOLN IL
847 PM CDT SAT AUG 8 2015
.UPDATE...
ISSUED AT 835 PM CDT SAT AUG 8 2015
WEAK SURFACE WIND SHIFT STILL DEPICTED ON THE LASTEST SURFACE
ANALYSIS OVER PARTS OF EAST CENTRAL THROUGH SOUTH CENTRAL IL
EARLY THIS EVENING. HAD A FEW LIGHT SHOWERS DEVELOP ALONG IT
EARLIER BUT NOT MUCH SINCE THEN. A BAND OF MID LEVEL CLOUDS
AND OCCASIONAL LIGHT SHOWERS STRETCHED FROM EAST CENTRAL IOWA
INTO PARTS OF CENTRAL ILLINOIS. THE STRONGER LOW LEVEL WARM
ADVECTION AND MOISTURE CONVERGENCE IS WELL OUT WEST OF OUR
AREA OVER THE MISSOURI RIVER VALLEY WHERE JUST RECENTLY CONVECTION
HAS FINALLY DEVELOPED OVER FAR SOUTHEAST NEBRASKA. THAT AREA
SHOULD INCREASE IN COVERAGE AS IT PUSHES EAST LATE THIS EVENING
WITH OUR AREA SEEING THE BULK OF THE SHOWERS AND STORMS DURING
THE MORNING HOURS OF SUNDAY. PRECIPITABLE WATER VALUES OF OVER
2 INCHES NOTED OVER PARTS OF SOUTHEAST NEBRASKA INTO WESTERN IOWA
WITH FORECAST MODELS SUGGESTING SIMILAR VALUES AS THE CONVECTIVE
SYSTEM ARRIVES IN OUR AREA EARLY SUNDAY MORNING. RAINFALL AMOUNTS
OF 1 TO 2 INCHES WILL BE POSSIBLE OVER PARTS OF WEST CENTRAL IL
BY SUNDAY MORNING WITH SOME OF THE MORE INTENSE THUNDERSTORMS.
HAVE MADE SOME MINOR ADJUSTMENTS TO THE GRIDS WITH RESPECT TO
TIMING OF THE MORE WIDESPREAD SHOWERS AND STORMS LATE TONIGHT AND
ADDED SOME LIGHTER SHOWERS FURTHER SOUTH AND EAST TO TAKE INTO
ACCOUNT THE WIDELY SCATTERED SHOWERS NOW OCCURRING WITH SOME OF
THE MID LEVEL CLOUDS TRACKING ESE ACROSS THE REGION THIS EVE.
SHOULD HAVE THE UPDATED ZONES OUT BY 900 PM.
&&
.SHORT TERM...(TONIGHT)
ISSUED AT 307 PM CDT SAT AUG 8 2015
REMNANTS OF AN MCS OVER EASTERN MO AT MID AFTERNOON HAS ISOLATED
LIGHT SHOWERS AND SPRINKLES OVER CENTRAL IL WEST OF I-57 AND
DRIFTING EASTWARD. MOST OF OUR AREA SHOULD STAY DRY INTO THIS
EVENING WITH JUST A FEW LIGHT SHOWERS OR SPRINKLES POSSIBLE OVER
PARTS OF CENTRAL IL WITH PARTLY TO MOSTLY CLOUDY SKIES. ANOTHER MCS
WILL LIKELY DEVELOP OVER WESTERN IA AND FAR EASTERN NEBRASKA ON NOSE
OF AN 35-45 KT 850 MB SW JET THIS EVENING AND TRACK ESE ACROSS IA
AND EVENTUALLY INTO CENTRAL IL DURING OVERNIGHT. 4KM WRF AND TAIL
END OF HRRR MODEL SHOWS MOST OF CONVECTION SREADING EAST TOWARD IL
RIVER VALLEY BETWEEN 08Z-10Z AND APPROACHING I-57 AROUND 12Z.
CONTINUED MENTION OF HEAVY RAIN FROM PEORIA NW LATE TONIGHT AFTER
09Z/4 AM WITH QPF OVERNIGHT HALF TO THREE QUARTER INCHES AND LOCALLY
1 INCH FROM GALESBURG AND MACOMB WEST. SPC HAS MARGINAL RISK OF
SEVERE STORMS OVERNIGHT WEST OF PEORIA AND SPRINGFIELD FOR GUSTY
WINDS AND SMALL HAIL WHILE SLIGHT RISK OF SEVERE IS FROM QUINCY
WESTWARD ACROSS NORTHERN MO AND SOUTHERN IA. SE IL/WABASH RIVER
VALLEY WILL LIKELY STAY DRY MOST OF TONIGHT AND PATCHY FOG COULD
FORM OVERNIGHT IN FAR SOUTHEAST IL WHERE LESS CLOUD COVER. MUGGY
LOWS TONIGHT IN THE UPPER 60S AND LOWER 70S WHICH IS CLOSE TO
CURRENT DEWPOINTS AND LIGHT WINDS TONIGHT.
.LONG TERM...(SUNDAY THROUGH SATURDAY)
ISSUED AT 307 PM CDT SAT AUG 8 2015
A THUNDERSTORM COMPLEX/MCS IS EXPECTED TO TRACK EASTWARD ACROSS
ILLINOIS SUNDAY MORNING...LIKELY WEAKENING THROUGH THE DAYTIME.
ALTHOUGH STILL WAITING FOR THIS SYSTEM TO DEVELOP AROUND EASTERN
NB/WESTERN IA THIS EVENING...RECENT TRENDS HAVE BEEN FOR SIMILAR
SYSTEMS TO DEVELOP SLIGHTLY SOUTHWARD FROM EARLY FORECASTS...AND
LATEST MODEL RUNS HINT AT THIS AS WELL. THEREFORE...HAVE TRENDED
HEAVIER PRECIPITATION AMOUNTS A BIT SOUTHWARD FROM PREVIOUS PACKAGE
WITH AMOUNTS FROM AROUND 1 TO 1.5 INCHES POSSIBLE NORTH OF I-72 AND
WEST OF I-55 BY NOON SUNDAY...WITH THE HIGHER END OF THAT RANGE MORE
LIKELY TOWARD THE GALESBURG AREA. LOWER AMOUNTS AND LOWER
PRECIPITATION CHANCES EXPECTED WITH THIS SYSTEM SOUTH OF I-72 TOWARD
THE EFFINGHAM/I-70 AREA.
A BIT OF A BREAK IN THUNDERSTORM ACTIVITY LIKELY FOR MIDDAY SUNDAY
AS THE OVERNIGHT SYSTEM MOVES OFF TO THE EAST. EXACT TIMING...CLOUD
COVER LEFT BEHIND...AND BOUNDARIES LEFT BEHIND FROM THE OVERNIGHT
SYSTEM WILL IMPACT THE POSSIBILITY OF ANOTHER THUNDERSTORM COMPLEX
DEVELOPING SUNDAY NIGHT. CURRENT MODEL CONSENSUS FORMS THIS FARTHER
SOUTH TOWARD THE OHIO VALLEY AREA AND HAVE TRENDED PRECIP CHANCES
TOWARD THAT AREA FOR SUNDAY NIGHT INTO MONDAY.
AFTER THAT...UPPER RIDGING WILL BUILD OVER THE CENTRAL CONUS AND
DEEP TROUGHING WILL DEVELOP DOWNSTREAM ACROSS THE GREAT LAKES/OHIO
RIVER VALLEY. AS A RESULT...MUCH OF THE EXTENDED BEYOND MONDAY IS
COOL/DRY. GFS/ECMWF SHOW THE NEXT FRONTAL BOUNDARY DROPPING INTO
THE GREAT LAKES AREA JUST NORTH OF CENTRAL IL FRIDAY. HOWEVER...BOTH
LARGELY DISSIPATE THE FEATURE AND WILL MENTION JUST A SLIGHT CHANCE
POP ACROSS THE NORTHERN HALF OF THE CWA ON FRIDAY UNTIL BETTER MODEL
CONSISTENCY IS ACHIEVED.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 600 PM CDT SAT AUG 8 2015
MAIN FORECAST CHALLENGE THIS PERIOD WILL BE TIMING OF A LARGE
COMPLEX OF STORMS THAT IS EXPECTED TO DEVELOP OVER SOUTHWEST
IOWA THIS EVENING AND TRACK EAST INTO OUR AREA AFTER 05Z. VFR
CONDITIONS ARE EXPECTED THIS EVENING UNTIL THE CLUSTER OF SHOWERS
ADN STORMS ARRIVES OVERNIGHT. ONCE THAT OCCURS...LOOK FOR CIGS AND
VSBYS TO DROP TO MVFR OR POSSIBLY A BRIEF PERIOD OF IFR CONDITIONS
IN SOME OF THE HEAVIER RAINFALL. THE MAIN PERIOD OF CONCERN
APPEARS TO BE FROM 05Z-13Z FROM WEST TO EAST ACROSS THE FORECAST
AREA. THE STORMS ARE THEN FORECAST TO EXIT CENTRAL IL BY EARLY
AFTERNOON WITH VFR CONDITIONS RETURNING. THERE WILL BE A CHANCE
FOR SOME REDEVELOPMENT OF SHOWERS AND STORMS BUT JUST WHERE THOSE
WILL IGNITE IS NOT CERTAIN THIS FAR OUT. SURFACE WINDS...WILL BE
LIGHT AND VARIABLE...MOSTLY FROM AN EAST TO SOUTHEAST DIRECTION
TONIGHT INTO SUNDAY. HOWEVER...WIND DIRECTION AND SPEED WILL BE
QUITE VARIABLE IN AN NEAR ANY THUNDERSTORM LATE TONIGHT AND THRU
THE MORNING HOURS.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SMITH
SHORT TERM...07
LONG TERM...ONTON
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
704 PM CDT SAT AUG 8 2015
.SHORT TERM...
320 PM CDT
THROUGH SUNDAY...
MAIN CONCERN IS WITH CONVECTIVE POTENTIAL LATE TONIGHT INTO
SUNDAY. RAOBS AND AIRCRAFT SOUNDINGS TODAY SHOWED AN ENVIRONMENT
HOSTILE TO PRECIP MAINTENANCE. THEREFORE DESPITE SOME FORCING FROM
A CONVECTIVELY INDUCED SHORTWAVE OVERHEAD...LIGHT RADAR ECHOES
OVER AREA ARE LIKELY VIRGA AND HAVE PULLED MENTION OF SPRINKLES
THE REST OF TODAY. CONVERGENT AXIS IN FRONTAL ZONE OF DISSIPATING
WEAK LOW OVER SOUTHERN LAKE MICHIGAN DID INITIATIVE SOME
CONVECTION OVER NORTH CENTRAL INDIANA...AND WOULD EXPECT FURTHER
DEVELOPMENT TO REMAIN EAST OF THE CWA. OVERALL...WITH PLENTY OF
CLOUD COVER WELL BACK TO THE WEST...INCLUDING PATCHY LOWER CLOUDS
IN SPOTS...JUST EXPECTING A MOSTLY CLOUDY REST OF THE DAY INTO
TONIGHT. VERY WEAK GRADIENT WILL YIELD LIGHT/CALM WINDS OVERNIGHT
AND LOW DEWPOINT SPREADS COULD SET STAGE FOR SOME PATCHY FOG OR
HAZE. LOW TEMPS WILL BE IN THE MID 60S TO AROUND 70.
FOCUS LATE TONIGHT INTO SUNDAY WILL BE ON MCS EXPECTED TO DEVELOP
OVER EASTERN NEBRASKA AND WESTERN IOWA THIS EVENING. MCS IS LIKELY
TO RIDE ALONG INSTABILITY AXIS THAT WILL MAINLY BE SOUTH OF THE
CWA OFF TO THE EAST-SOUTHEAST INTO SUNDAY MORNING. CONSENSUS OF
MODEL GUIDANCE IS TO KEEP INSTABILITY MINIMAL AT BEST FOR MUCH OF
THE CWA...LIMITING THUNDER POTENTIAL. CANNOT COMPLETELY RULE OUT
THUNDER GIVEN MODEST LOW LEVEL JET/WAA REGIME. RECENT HI-RES
CAMS...INCLUDING 4KM NAM AND EXPERIMENTAL HRRR DEPICT A REASONABLE
SCENARIO IN WHICH STRATIFORM NORTH OF MCS OVERSPREADS MUCH OF CWA
FROM WESTNORTHWEST TO EAST SOUTHEAST AFTER MIDNIGHT THROUGH MID
SUNDAY MORNING/BY WHICH TIME IT WILL PROBABLY BE DECAYING. HAVE
FOCUSED CATEGORICAL POPS INTO SOUTHERN CWA WHERE CONFIDENCE IS
HIGHEST IN WIDESPREAD COVERAGE. ITS POSSIBLE FAR NORTHEAST CWA
COULD SEE LITTLE OR NO RAIN. BEST CHANCE FOR HEAVY DOWNPOURS LOOKS
TO BE IN FAR SOUTHERN CWA WHERE MORE ROBUST CONVECTION COULD PASS
THROUGH...THOUGH ANY THREAT FOR STRONG TO SEVERE STORMS SHOULD
STAY SOUTHWEST OF THE CWA GIVEN ANTICIPATED DECAYING TREND OF MCS.
A GOOD DEAL OF UNCERTAINTY THE REMAINDER OF SUNDAY REGARDING
CONVECTIVE TRENDS. A SURFACE LOW LOOKS TO EVOLVE EASTWARD INTO THE
MID MISSISSIPPI VALLEY BY LATER IN THE DAY...WITH RETURN FLOW AND
WEST-SOUTHWEST LLJ ALSO DEVELOPING. LINGERING CLOUD COVER WILL
LIMIT DESTABILIZATION AND THUNDER POTENTIAL...ESPECIALLY FARTHER
NORTH UNTIL LATE DAY. ANOTHER SHORTWAVE WILL APPROACH FROM WEST IN
LATE AFTERNOON AND THERE SHOULD BE ENOUGH 925-850 MB MOISTURE
CONVERGENCE TO SUPPORT CHANCE POPS NORTH OF I-80 AND LIKELIESSOUTH
OF I-80. MODERATE WESTERLY MIDLEVEL FLOW WILL RESULT IN 30-40 KT
OF WEST-NORTHWEST 0-6KM SHEAR. THIS WILL SUPPORT SOME THREAT FOR
STRONG TO SEVERE STORMS WELL SOUTH OF I-80 CLOSER TO EXPECTED
TRACK OF SFC LOW AND WHERE TEMPS AROUND 80 AND LOW-MID 70S
DEWPOINTS COULD BRING SLIGHTLY BETTER INSTABILITY. MAIN THREAT
WOULD BE GUSTY TO DAMAGING WINDS...AS HAIL APPEARS UNLIKELY WITH
700-500 MB LAPSE RATES LESS THAN 6 CELSIUS PER KM. SUNDAY OVERALL
WILL BE A CLOUDY AND MUGGY DAY...WITH HIGHS IN THE MID 70S TO
AROUND 80.
RC
&&
.LONG TERM...
320 PM CDT
SUNDAY NIGHT THROUGH SATURDAY...
THE BEST CHANCE FOR PRECIP IN THE EXTENDED WILL BE SUNDAY EVENING
THROUGH MONDAY AFTERNOON...WITH VERY SLIGHT CHANCES OF PRECIP LATE
NEXT WEEK.
A COMPLEX OF STORMS WILL BE DIMINISHING OVER THE REGION SUNDAY
EVENING AND NIGHT. THE UPPER LEVEL VORTICITY PATTERN IS VERY CHAOTIC
WITH GUIDANCE INDICATING THE MAIN MCV WILL BE OVER CENTRAL IL AND
VORT STREAMERS ASSOCIATED WITH THE UPPER LEVEL TROUGH WILL BE OVER
WISCONSIN. WITH SUCH A MESSY PATTERN...DECIDED TO ONLY MAKE MINOR
ADJUSTMENTS TO PRECIP CHANCES SUNDAY NIGHT. HAVE A CHANCE OF
THUNDERSTORMS ALONG AND EAST OF I-39 WITH BETTER CHANCES EAST OF I-
55. COULD SEE A FEW STRONG TO SEVERE STORMS SOUTH OF I-80 BUT
CONDITIONS WILL BE WEAKENING AS THE EVENING PROGRESSES.
OVERALL...HAVE LOW CONFIDENCE IN EXACTLY HOW SUNDAY NIGHT WILL PLAY
OUT DUE TO SO MANY MESOSCALE FEATURES AND WHETHER OR NOT THE
ATMOSPHERE WILL BE ABLE TO RECOVER FROM SUNDAY MORNING/S STORMS.
A SHORT WAVE MOVING WITH THE UPPER LEVEL TROUGH ROTATES THROUGH
MONDAY WITH A DECENT VORTICITY STREAMER. WENT WITH A CHANCE OF
SHOWERS AND STORMS MAINLY NORTH OF I-80 MONDAY. THINKING THE NAM IS
ONCE AGAIN TOO MOIST LEADING TO TOO MUCH CONVECTIVE DEVELOPMENT.
THINKING SHOWERS AND STORMS WILL DRIFT SOUTH OF THE IL/WI STATE LINE
MONDAY AFTERNOON AND THEN WEAKEN AS THEY CONTINUE TO SHIFT SOUTH
MONDAY EVENING. MONDAY EVENING MAY END UP BEING DRY...BUT DID NOT
HAVE ENOUGH CONFIDENCE IN A DRY FORECAST SO KEPT A SLIGHT CHANCE OF
SHOWERS AND STORMS ALONG AND SOUTH OF I-80 MONDAY EVENING.
THE UPPER LEVEL TROUGH AXIS SHIFTS EAST THROUGH WISCONSIN WITH
COOLER UPPER LEVEL AIR SINKING SOUTH THROUGH THE REGION. HIGH
PRESSURE THEN BUILDS IN FOR WEDNESDAY AND THURSDAY LEADING TO DRY
CONDITIONS THROUGH THURSDAY. HIGH TEMPS TUESDAY WILL BE AROUND
80...THEN IN THE UPPER 70S WEDNESDAY. LAKE BREEZES BOTH DAYS WILL
KEEP LOCATIONS ALONG THE LAKE IN THE MID 70S. TEMPS REBOUND INTO
THE LOW TO MID 80S THURSDAY WITH NO LAKE COOLING.
THE NEXT LOW PRESSURE SYSTEM MOVES OVER JAMES BAY THURSDAY EVENING
AND PUSHES THE HIGH PRESSURE SOUTH OVER THE OHIO VALLEY. THE LOWS
COLD FRONT SINKS SOUTH OVER FAR NORTHERN IL FRIDAY AFTERNOON SO HAVE
A SLIGHT CHANCE TO CHANCE OF SHOWERS AND STORMS.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* NORTHEAST WINDS 10 KTS OR LESS THIS EVENING.
* PERIOD OF RAIN LIKELY SUNDAY MORNING...POSSIBLY WITH MVFR
CIGS/VIS.
* CHANCE OF SHOWERS AGAIN LATER IN THE DAY...ISOLATED THUNDER
POSSIBLE BUT MORE LIKELY SOUTH OF TERMINALS.
RATZER
//DISCUSSION...UPDATED 00Z...
WEAK SFC LOW PRESSURE EAST OF AREA ALONG MI/IN BORDER EARLY THIS
EVENING...WITH WEAK HIGH PRESSURE OVER WI/NORTHERN IL AND THE
LAKE. WINDS HAVE SHIFTED TO THE NORTHEAST ACROSS THE AREA AS THE
LOW DEPARTS...AND WHILE SOME GUSTS IN THE 15 KT RANGE HAVE BEEN
NOTED AS THE WIND SHIFT PUSHES DOWN THE LAKE SHORE...WINDS INLAND
ARE EXPECTED TO REMAIN 10 KTS OR LESS THIS EVENING.
LACK OF STRONG DRYING MAY ALLOW FOR DEVELOPMENT OF PATCHY MVFR
CIGS OR 4-5SM HAZE/FOG LATE TONIGHT...THOUGH EXTENSIVE CLOUD COVER
WILL NOT LIKELY SUPPORT WIDESPREAD VISIBILITY REDUCTION BELOW
MVFR. ATTENTION THEN TURNS TO A MID-LEVEL DISTURBANCE APPROACHING
FROM THE PLAINS EARLY SUNDAY MORNING...WITH AN ATTENDANT
THUNDERSTORM COMPLEX CURRENTLY TAKING SHAPE FROM KS INTO IA.
HIGH-RES MODELS DEPICT THIS COMPLEX MOVING INTO IL EARLY SUNDAY
MORNING...THOUGH WITH THE GREATEST POTENTIAL FOR THUNDER MAINLY
SOUTH OF THE TERMINALS ALONG WARM FRONT. MORNING RAIN/CLOUD COVER
WILL ALSO LIKELY SUPPRESS THE WARM FRONT AND GREATER INSTABILITY
SOUTH OF THE TERMINALS WITH LITTLE FOCUS FOR ORGANIZED
THUNDERSTORM DEVELOPMENT IN THE IMMEDIATE VICINITY. HIGH-RES
MODELS THEN DEPICT ANOTHER CLUSTER OF THUNDERSTORMS PASSING SOUTH
OF THE TERMINALS SUNDAY EVENING.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* HIGH IN WINDS AND OTHER ELEMENTS THIS EVENING.
* MEDIUM IN RAIN COVERAGE/TIMING AND MVFR POTENTIAL SUNDAY
MORNING.
* MEDIUM-LOW IN WINDS SUNDAY...THOUGH SHOULD BE GENERALLY LESS
THAN 10 KTS.
* LOW IN SHRA/ISOLATED TSRA COVERAGE SUNDAY AFTERNOON/EVE.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...
MONDAY...CHANCE OF SHRA/TSRA AND MVFR. NORTH-NORTHEAST WINDS.
TUESDAY AND WEDNESDAY...VFR. NORTHEAST WINDS.
THURSDAY...VFR. WEST-SOUTHWEST WINDS.
FRIDAY...SLIGHT CHANCE TSRA. WEST-SOUTHWEST WINDS.
RATZER
&&
.MARINE...
320 PM CDT
HIGH PRESSURE STRETCHES FROM QUEBEC THROUGH THE OHIO VALLEY WHILE
LOW PRESSURE IS OVER MANITOBA. BOTH SYSTEMS WILL SHIFT EAST WITH THE
LOW REACHING JAMES BAY BY MONDAY MORNING. AS SUCH LIGHT NORTHEAST
WINDS BECOME SOUTH TO SOUTHEAST SUNDAY. THE TROUGH ASSOCIATED WITH
THE LOWS COLD/STATIONARY FRONT SHIFTS THROUGH LATE SUNDAY NIGHT INTO
MONDAY MORNING WITH WINDS BECOMING NORTH BEHIND IT. A WEAK CLOSED
LOW FORMS OVER THE EASTERN GREAT LAKES MONDAY EVENING AND DEEPENS AS
IT SHIFTS NORTHEAST. AT THE SAME TIME HIGH PRESSURE WILL BE PUSHING
EAST OVER THE WESTERN GREAT LAKES. THIS WILL LEAD TO NORTH WINDS
INCREASING TO 10 TO 20 KT MONDAY NIGHT THROUGH TUESDAY NIGHT. WINDS
WEAKEN WEDNESDAY WITH THE HIGH OVERHEAD...AND THEN BACK TO SOUTHWEST
AS THE HIGH IS PUSHED SOUTH BY THE NEXT LOW OVER JAMES BAY THURSDAY.
JEE
&&
.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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AREA FORECAST DISCUSSION
NWS LINCOLN IL
603 PM CDT SAT AUG 8 2015
.SHORT TERM...(TONIGHT)
ISSUED AT 307 PM CDT SAT AUG 8 2015
REMNANTS OF AN MCS OVER EASTERN MO AT MID AFTERNOON HAS ISOLATED
LIGHT SHOWERS AND SPRINKLES OVER CENTRAL IL WEST OF I-57 AND
DRIFTING EASTWARD. MOST OF OUR AREA SHOULD STAY DRY INTO THIS
EVENING WITH JUST A FEW LIGHT SHOWERS OR SPRINKLES POSSIBLE OVER
PARTS OF CENTRAL IL WITH PARTLY TO MOSTLY CLOUDY SKIES. ANOTHER MCS
WILL LIKELY DEVELOP OVER WESTERN IA AND FAR EASTERN NEBRASKA ON NOSE
OF AN 35-45 KT 850 MB SW JET THIS EVENING AND TRACK ESE ACROSS IA
AND EVENTUALLY INTO CENTRAL IL DURING OVERNIGHT. 4KM WRF AND TAIL
END OF HRRR MODEL SHOWS MOST OF CONVECTION SREADING EAST TOWARD IL
RIVER VALLEY BETWEEN 08Z-10Z AND APPROACHING I-57 AROUND 12Z.
CONTINUED MENTION OF HEAVY RAIN FROM PEORIA NW LATE TONIGHT AFTER
09Z/4 AM WITH QPF OVERNIGHT HALF TO THREE QUARTER INCHES AND LOCALLY
1 INCH FROM GALESBURG AND MACOMB WEST. SPC HAS MARGINAL RISK OF
SEVERE STORMS OVERNIGHT WEST OF PEORIA AND SPRINGFIELD FOR GUSTY
WINDS AND SMALL HAIL WHILE SLIGHT RISK OF SEVERE IS FROM QUINCY
WESTWARD ACROSS NORTHERN MO AND SOUTHERN IA. SE IL/WABASH RIVER
VALLEY WILL LIKELY STAY DRY MOST OF TONIGHT AND PATCHY FOG COULD
FORM OVERNIGHT IN FAR SOUTHEAST IL WHERE LESS CLOUD COVER. MUGGY
LOWS TONIGHT IN THE UPPER 60S AND LOWER 70S WHICH IS CLOSE TO
CURRENT DEWPOINTS AND LIGHT WINDS TONIGHT.
.LONG TERM...(SUNDAY THROUGH SATURDAY)
ISSUED AT 307 PM CDT SAT AUG 8 2015
A THUNDERSTORM COMPLEX/MCS IS EXPECTED TO TRACK EASTWARD ACROSS
ILLINOIS SUNDAY MORNING...LIKELY WEAKENING THROUGH THE DAYTIME.
ALTHOUGH STILL WAITING FOR THIS SYSTEM TO DEVELOP AROUND EASTERN
NB/WESTERN IA THIS EVENING...RECENT TRENDS HAVE BEEN FOR SIMILAR
SYSTEMS TO DEVELOP SLIGHTLY SOUTHWARD FROM EARLY FORECASTS...AND
LATEST MODEL RUNS HINT AT THIS AS WELL. THEREFORE...HAVE TRENDED
HEAVIER PRECIPITATION AMOUNTS A BIT SOUTHWARD FROM PREVIOUS PACKAGE
WITH AMOUNTS FROM AROUND 1 TO 1.5 INCHES POSSIBLE NORTH OF I-72 AND
WEST OF I-55 BY NOON SUNDAY...WITH THE HIGHER END OF THAT RANGE MORE
LIKELY TOWARD THE GALESBURG AREA. LOWER AMOUNTS AND LOWER
PRECIPITATION CHANCES EXPECTED WITH THIS SYSTEM SOUTH OF I-72 TOWARD
THE EFFINGHAM/I-70 AREA.
A BIT OF A BREAK IN THUNDERSTORM ACTIVITY LIKELY FOR MIDDAY SUNDAY
AS THE OVERNIGHT SYSTEM MOVES OFF TO THE EAST. EXACT TIMING...CLOUD
COVER LEFT BEHIND...AND BOUNDARIES LEFT BEHIND FROM THE OVERNIGHT
SYSTEM WILL IMPACT THE POSSIBILITY OF ANOTHER THUNDERSTORM COMPLEX
DEVELOPING SUNDAY NIGHT. CURRENT MODEL CONSENSUS FORMS THIS FARTHER
SOUTH TOWARD THE OHIO VALLEY AREA AND HAVE TRENDED PRECIP CHANCES
TOWARD THAT AREA FOR SUNDAY NIGHT INTO MONDAY.
AFTER THAT...UPPER RIDGING WILL BUILD OVER THE CENTRAL CONUS AND
DEEP TROUGHING WILL DEVELOP DOWNSTREAM ACROSS THE GREAT LAKES/OHIO
RIVER VALLEY. AS A RESULT...MUCH OF THE EXTENDED BEYOND MONDAY IS
COOL/DRY. GFS/ECMWF SHOW THE NEXT FRONTAL BOUNDARY DROPPING INTO
THE GREAT LAKES AREA JUST NORTH OF CENTRAL IL FRIDAY. HOWEVER...BOTH
LARGELY DISSIPATE THE FEATURE AND WILL MENTION JUST A SLIGHT CHANCE
POP ACROSS THE NORTHERN HALF OF THE CWA ON FRIDAY UNTIL BETTER MODEL
CONSISTENCY IS ACHIEVED.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 600 PM CDT SAT AUG 8 2015
MAIN FORECAST CHALLENGE THIS PERIOD WILL BE TIMING OF A LARGE
COMPLEX OF STORMS THAT IS EXPECTED TO DEVELOP OVER SOUTHWEST
IOWA THIS EVENING AND TRACK EAST INTO OUR AREA AFTER 05Z. VFR
CONDITIONS ARE EXPECTED THIS EVENING UNTIL THE CLUSTER OF SHOWERS
ADN STORMS ARRIVES OVERNIGHT. ONCE THAT OCCURS...LOOK FOR CIGS AND
VSBYS TO DROP TO MVFR OR POSSIBLY A BRIEF PERIOD OF IFR CONDITIONS
IN SOME OF THE HEAVIER RAINFALL. THE MAIN PERIOD OF CONCERN
APPEARS TO BE FROM 05Z-13Z FROM WEST TO EAST ACROSS THE FORECAST
AREA. THE STORMS ARE THEN FORECAST TO EXIT CENTRAL IL BY EARLY
AFTERNOON WITH VFR CONDITIONS RETURNING. THERE WILL BE A CHANCE
FOR SOME REDEVELOPMENT OF SHOWERS AND STORMS BUT JUST WHERE THOSE
WILL IGNITE IS NOT CERTAIN THIS FAR OUT. SURFACE WINDS...WILL BE
LIGHT AND VARIABLE...MOSTLY FROM AN EAST TO SOUTHEAST DIRECTION
TONIGHT INTO SUNDAY. HOWEVER...WIND DIRECTION AND SPEED WILL BE
QUITE VARIABLE IN AN NEAR ANY THUNDERSTORM LATE TONIGHT AND THRU
THE MORNING HOURS.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...07
LONG TERM...ONTON
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
248 PM CDT FRI AUG 7 2015
.UPDATE...
1143 AM CDT
A WEAKENING SURFACE LOW RESIDES OVER FAR WESTERN WISCONSIN...WITH
HIGH PRESSURE CENTERED OVER THE EASTERN AND CENTRAL GREAT LAKES
LATE THIS MORNING. GLANCING BLOW FROM THE MID/UPPER WAVE
ASSOCIATED FROM THE SURFACE LOW THAT IS MAINLY FOCUSED INTO
WISCONSIN WILL GRADUALLY SPREAD ISOLATED TO WIDELY SCATTERED
SHOWERS/SPRINKLES EASTWARD IN NORTHERN ILLINOIS NORTH OF
INTERSTATE 80. WEAKER FORCING WITH SOUTHWARD EXTENT AND DRY LOWER
LEVELS NOTED ON 12Z DVN RAOB AND AIRCRAFT SOUNDINGS WILL KEEP
AREAL COVERAGE LOW. MANY AREAS WILL NOT SEE ANY MEASURABLE
RAINFALL GIVEN THE WEAK FORCING AND LOW AREAL COVERAGE. IN
ADDITION...POOR MIDLEVEL LAPSE RATES WILL LIMIT
DESTABILIZATION...WITH ML AND SB CAPE AXIS STAYING WEST OF THE
AREA THROUGH THE AFTERNOON. THERE COULD BE ENOUGH MUCAPE FOR
SLIGHT CHANCE OF THUNDER THIS AFTERNOON MAINLY NORTHWEST OF A
STERLING TO ANTIOCH LINE...THOUGH THIS COULD EVEN END UP BULLISH.
TEMPERATURES FROM INHERITED FORECAST HAVE BEEN TRACKING VERY WELL
WITH HOURLY OBS...SO HIGHS GENERALLY IN THE LOWER 80S APPEAR ON
TRACK...WITH MID 80S POSSIBLE IN CHICAGO HEAT ISLAND AWAY FROM
MINOR COOLING INFLUENCE OF LAKE BREEZE.
RC
&&
.SHORT TERM...
349 AM CDT
THROUGH SUNDAY...
CONCERNS REVOLVE AROUND PRECIPITATION CHANCES EACH OF THE NEXT FEW
DAYS.
A COMPACT BUT POTENT UPPER LEVEL DISTURBANCE IN MN IS PRODUCING A
COMPLEX OF THUNDERSTORMS NOW MOVING INTO WESTERN WISCONSIN. THERE IS
A WEAK SURFACE REFLECTION WITH THIS FEATURE WHERE THE MORE ORGANIZED
ACTIVITY IS ONGOING. CLOSER TO HOME...SURFACE HIGH PRESSURE IS
HOLDING FIRM JUST NEAR LAKE HURON...WITH THE RIDGE AXIS ORIENTED
SOUTHWESTWARD. IR IMAGERY EARLY THIS MORNING HAS SHOWN A CONTINUAL
EROSION OF THE DEEPER CLOUDS ON THE SOUTHERN END OF THIS COMPLEX AS
IT MOVES INTO DRIER AIR FARTHER SOUTH AND EAST.
AN UPPER LEVEL JET MOVING INTO THE NORTHERN PLAINS WILL ALLOW THIS
UPPER DISTURBANCE TO MOVE SOUTH AND EAST TOWARD THE AREA
TODAY...EVEN OUTRUNNING THE SURFACE LOW. MUCH OF THE NEAR TERM
GUIDANCE KEEPS ERODING PRECIP SOUTH OF THE WISCONSIN BORDER AHEAD OF
THIS SYSTEM. THE EXCEPTION TO THIS THE EXPERIMENTAL HRRR AND
SEVERAL HOP-WRF MEMBERS WHICH ARE A BIT MORE AGGRESSIVE WITH
DRIVING PRECIP THROUGH THE AREA...ESPECIALLY THIS AFTERNOON.
OBSERVATIONS SUGGEST SOME CONTINUED DEVELOPMENT SOUTHWARD THROUGH
THE MORNING INTO THE INSTABILITY AXIS WHICH WILL GRADUALLY
APPROACH FROM THE WEST TODAY. HAVE STILL KEPT POPS ON THE LOWER
SIDE AWAY FROM NORTH CENTRAL ILLINOIS AND POINTS WEST...THOUGH
EXPECT OUR NORTHWESTERN ZONES INTO WINNEBAGO/BOONE/MCHENRY
COUNTIES STAND A CHANCE OF SOME SHOWERS OR A STRAY STORM LATER
THIS MORNING INTO THE AFTERNOON. CONTINUED DRY AIR SHOULD FURTHER
ERODE AT THE PRECIP...THOUGH AS THE DAY GOES ON AND THE
INSTABILITY AXIS SHIFTS EASTWARD WITH THE UPPER LOW...EXPECT THAT
SOME SHOWERS WILL BE POSSIBLE. SOUNDINGS ARE NOT THRILLED ABOUT
THE THUNDER POTENTIAL CLOSER TO CHICAGO WITH CAPPING HOLDING.
TONIGHT...THE UPPER LOW SHIFTS EAST AND OUTPACES THE SURFACE LOW AND
THUS EXPECT SOME DECREASE IN COVERAGE OF SHOWERS AND COULD JUST BE
DRY...THOUGH WILL HANG ONTO A LOW POP MENTION OVERNIGHT FOR SOME
LINGERING LOW LEVEL CONVERGENCE.
SATURDAY...FOCUS SHIFTS TO ENERGY PROPAGATING FROM THE TROUGH OFF
THE CA COAST THIS MORNING. THIS IS FORECAST TO RIDE A DECENT UPPER
JET THROUGH THE PLAINS OVERNIGHT INTO THE MORNING AND ALONG THE
NORTHERN FRINGES OF THE UPPER LEVEL RIDGE AXIS THAT EXTENDS FROM
TEXAS NORTH INTO THE CENTRAL PLAINS. THIS WAVE CRUISES THROUGH
SATURDAY MORNING WITH SURFACE HIGH PRESSURE IN PLACE AND A LACK OF
DEEPER MOISTURE...SO HAVE CONTINUED A DRY FORECAST...AND THAT GOES
FOR SATURDAY AFTERNOON AS WELL AS THE WAVE MOVES EAST. WILL HAVE
TO WATCH THE MORNING PERIOD IF THE LOWER LEVELS MOISTEN UP A BIT
MORE THAN FORECAST THAT A STRAY SHOWER OR STORM WOULD BE POSSIBLE.
THE NAM IS A LITTLE SLOWER WITH THIS WAVE...BUT STILL DRY IN THE
AFTERNOON AS THE STRONGER FORCING REMAINS TO OUR WEST.
CHANCES FOR SHOWERS AND STORMS INCREASE SATURDAY NIGHT INTO SUNDAY
MORNING AS WE GET A BETTER CO-LOCATION OF DEEPER MOISTURE TRANSPORT
COURTESY OF A DECENT LOW LEVEL JET...ANOTHER PACIFIC
DISTURBANCE...AND PWATS APPROACHING 2 INCHES. WE HANG ONTO SE FLOW
AT THE SURFACE FARTHER EAST...WHICH WOULD THEN GIVE THE HIGHER
CONCERN FOR MODERATE TO HEAVY PRECIP RATES SOUTH AND WEST. THERE
IS A SEVERE THREAT GIVEN THE MODEST WESTERLY FLOW NORTH OF THE
RIDGE AND HIGHER DEWPOINTS ADVECTING IN...BUT DESTABILIZATION
CONCERNS EXIST AT THIS POINT IN TIME TO NAIL DOWN THE SPECIFICS
YET. THE MARGINAL RISK IS FOCUSED IN OUR SOUTHWEST AT THIS TIME.
KMD
&&
.LONG TERM...
407 AM CDT
SUNDAY NIGHT THROUGH THURSDAY...
.LONG TERM...
AN UPPER LEVEL LOW QUICKLY MOVES EASTWARD THROUGH SOUTHERN ONTARIO SUNDAY
NIGHT INTO MONDAY...AS THIS OCCURS AND A DEEP TROUGH BUILDS ALONG
THE PACIFIC COAST...UPPER LEVEL RIDGING IN THE WEST WILL CONTINUE
TO AMPLIFY THE FLOW PATTERN. NW FLOW ON MONDAY WILL KEEP A CHANCE
FOR SHOWERS AND STORMS AROUND AS A WEAK COLD FRONT MOVES THROUGH.
ANOTHER DISTURBANCE GLIDES BY TO OUR NORTH TUESDAY FOR A SOMEWHAT
COOLER THOUGH GENERALLY DRY DAY. A STRAY SHOWER IS POSSIBLE. HIGH
PRESSURE BUILDS IN FOR MID WEEK.
KMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* LAKE BREEZE POTENTIAL THIS AFTERNOON.
* ISOLATED SHOWERS TONIGHT.
* BRIEF REDUCTION IN VSBY DUE TO FOG SATURDAY MORNING.
MM
//DISCUSSION...UPDATED 18Z...
TERMINAL DOPPLER RADAR INDICATES LAKE BREEZE BOUNDARY MAKING
INROADS TOWARD ORD EARLY THIS AFTERNOON. LOW LEVEL SOUTHWEST WINDS
HAVE BEEN COMBATING THIS WEAK BOUNDARY TODAY...AND IT DOES APPEAR
THAT THE BOUNDARY MAY REMAIN EAST OF ORD. THE RESULT LEAVES PREVAILING
SSW WINDS LIKELY. IF THE BOUNDARY WERE TO PENETRATE FURTHER...IT
WILL LIKELY BE AFTER A FEW MORE HOURS OF DAYTIME HEATING...NEAR
22Z.
OVERNIGHT A NON-STANDARD WARM FRONT WILL APPROACH THE
AREA...PROVIDING FOCUS FOR SOME SCATTERED SHOWERS. TAF SITES WILL
BE IN THE WARM SECTOR OF THE LOW IN THE MORNING WHICH WILL HELP
FORMATION OF FOG IN THE MORNING. THIS FRONT BECOMES NEARLY
STATIONARY EARLY SATURDAY. THE PRESSURE PATTERN WILL FAVOR WEAK
SOUTHERLY WINDS DURING THE DAY...VEERING TO BECOME NORTHWEST IN
THE LATE AFTERNOON. A LAKE BREEZE IS AGAIN POSSIBLE AFTER 22Z.
MM
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM-LOW IN LAKE BREEZE TODAY.
* MEDIUM IN SHOWERS TONIGHT.
* MEDIUM-LOW IN FOG DENSITY.
MM
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...SLIGHT CHANCE OF THUNDERSTORMS.
SUNDAY...CHANCE OF THUNDERSTORMS.
MONDAY...CHANCE OF THUNDERSTORMS.
TUESDAY...VFR.
WEDNESDAY...VFR.
THURSDAY...VFR.
RODRIGUEZ
&&
.MARINE...
302 AM CDT
LIGHTER EASTERLY WINDS IN PLACE EARLY THIS MORNING WILL OBSERVE A
STEADY INCREASE TODAY WHILE SHIFTING TO MORE OF A SOUTHERLY
COMPONENT...AS LOW PRESSURE TO THE WEST OVER THE NORTHERN PLAINS
SLOWLY PUSHES EAST. STILL THINK A 10 TO 20 KT WIND WILL BE THE
HIGHEST TODAY...BUT SOME GUIDANCE IS HINTING AT POSSIBLE HIGHER
SPEEDS THROUGHOUT THE DAY. ALTHOUGH I DID INCREASE SPEEDS...DID
NOT GO AS HIGH. HOWEVER...DID MENTION A FEW GUSTS TO 25KT FOR THE
OPEN WATERS TODAY. IT DOES LOOK LIKE A BETTER WINDOW FOR STRONGER
WINDS OF 15 TO 25 KT ACROSS THE NORTH TONIGHT INTO SATURDAY
MORNING...AND HAVE TRENDED THAT WAY WITH THE FORECAST. THIS WILL
BE IN RESPONSE TO THE APPROACHING LOW...BUT WITH IT
WEAKENING...SPEEDS WILL DIMINISH SATURDAY INTO SATURDAY NIGHT.
EXACT TIMING AND PLACEMENT OF THE NEXT SYSTEM LATE IN THE WEEKEND
IS STILL UNCERTAIN BUT IT DOES APPEAR TO BE ANOTHER PERIOD WHEN
SPEEDS WILL ONCE AGAIN INCREASE...AT LEAST FOR THE SOUTHERN HALF
OF THE LAKE.
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
1252 PM CDT FRI AUG 7 2015
.UPDATE...
1143 AM CDT
A WEAKENING SURFACE LOW RESIDES OVER FAR WESTERN WISCONSIN...WITH
HIGH PRESSURE CENTERED OVER THE EASTERN AND CENTRAL GREAT LAKES
LATE THIS MORNING. GLANCING BLOW FROM THE MID/UPPER WAVE
ASSOCIATED FROM THE SURFACE LOW THAT IS MAINLY FOCUSED INTO
WISCONSIN WILL GRADUALLY SPREAD ISOLATED TO WIDELY SCATTERED
SHOWERS/SPRINKLES EASTWARD IN NORTHERN ILLINOIS NORTH OF
INTERSTATE 80. WEAKER FORCING WITH SOUTHWARD EXTENT AND DRY LOWER
LEVELS NOTED ON 12Z DVN RAOB AND AIRCRAFT SOUNDINGS WILL KEEP
AREAL COVERAGE LOW. MANY AREAS WILL NOT SEE ANY MEASURABLE
RAINFALL GIVEN THE WEAK FORCING AND LOW AREAL COVERAGE. IN
ADDITION...POOR MIDLEVEL LAPSE RATES WILL LIMIT
DESTABILIZATION...WITH ML AND SB CAPE AXIS STAYING WEST OF THE
AREA THROUGH THE AFTERNOON. THERE COULD BE ENOUGH MUCAPE FOR
SLIGHT CHANCE OF THUNDER THIS AFTERNOON MAINLY NORTHWEST OF A
STERLING TO ANTIOCH LINE...THOUGH THIS COULD EVEN END UP BULLISH.
TEMPERATURES FROM INHERITED FORECAST HAVE BEEN TRACKING VERY WELL
WITH HOURLY OBS...SO HIGHS GENERALLY IN THE LOWER 80S APPEAR ON
TRACK...WITH MID 80S POSSIBLE IN CHICAGO HEAT ISLAND AWAY FROM
MINOR COOLING INFLUENCE OF LAKE BREEZE.
RC
&&
.SHORT TERM...
349 AM CDT
THROUGH SUNDAY...
CONCERNS REVOLVE AROUND PRECIPITATION CHANCES EACH OF THE NEXT FEW
DAYS.
A COMPACT BUT POTENT UPPER LEVEL DISTURBANCE IN MN IS PRODUCING A
COMPLEX OF THUNDERSTORMS NOW MOVING INTO WESTERN WISCONSIN. THERE IS
A WEAK SURFACE REFLECTION WITH THIS FEATURE WHERE THE MORE ORGANIZED
ACTIVITY IS ONGOING. CLOSER TO HOME...SURFACE HIGH PRESSURE IS
HOLDING FIRM JUST NEAR LAKE HURON...WITH THE RIDGE AXIS ORIENTED
SOUTHWESTWARD. IR IMAGERY EARLY THIS MORNING HAS SHOWN A CONTINUAL
EROSION OF THE DEEPER CLOUDS ON THE SOUTHERN END OF THIS COMPLEX AS
IT MOVES INTO DRIER AIR FARTHER SOUTH AND EAST.
AN UPPER LEVEL JET MOVING INTO THE NORTHERN PLAINS WILL ALLOW THIS
UPPER DISTURBANCE TO MOVE SOUTH AND EAST TOWARD THE AREA
TODAY...EVEN OUTRUNNING THE SURFACE LOW. MUCH OF THE NEAR TERM
GUIDANCE KEEPS ERODING PRECIP SOUTH OF THE WISCONSIN BORDER AHEAD OF
THIS SYSTEM. THE EXCEPTION TO THIS THE EXPERIMENTAL HRRR AND
SEVERAL HOP-WRF MEMBERS WHICH ARE A BIT MORE AGGRESSIVE WITH
DRIVING PRECIP THROUGH THE AREA...ESPECIALLY THIS AFTERNOON.
OBSERVATIONS SUGGEST SOME CONTINUED DEVELOPMENT SOUTHWARD THROUGH
THE MORNING INTO THE INSTABILITY AXIS WHICH WILL GRADUALLY
APPROACH FROM THE WEST TODAY. HAVE STILL KEPT POPS ON THE LOWER
SIDE AWAY FROM NORTH CENTRAL ILLINOIS AND POINTS WEST...THOUGH
EXPECT OUR NORTHWESTERN ZONES INTO WINNEBAGO/BOONE/MCHENRY
COUNTIES STAND A CHANCE OF SOME SHOWERS OR A STRAY STORM LATER
THIS MORNING INTO THE AFTERNOON. CONTINUED DRY AIR SHOULD FURTHER
ERODE AT THE PRECIP...THOUGH AS THE DAY GOES ON AND THE
INSTABILITY AXIS SHIFTS EASTWARD WITH THE UPPER LOW...EXPECT THAT
SOME SHOWERS WILL BE POSSIBLE. SOUNDINGS ARE NOT THRILLED ABOUT
THE THUNDER POTENTIAL CLOSER TO CHICAGO WITH CAPPING HOLDING.
TONIGHT...THE UPPER LOW SHIFTS EAST AND OUTPACES THE SURFACE LOW AND
THUS EXPECT SOME DECREASE IN COVERAGE OF SHOWERS AND COULD JUST BE
DRY...THOUGH WILL HANG ONTO A LOW POP MENTION OVERNIGHT FOR SOME
LINGERING LOW LEVEL CONVERGENCE.
SATURDAY...FOCUS SHIFTS TO ENERGY PROPAGATING FROM THE TROUGH OFF
THE CA COAST THIS MORNING. THIS IS FORECAST TO RIDE A DECENT UPPER
JET THROUGH THE PLAINS OVERNIGHT INTO THE MORNING AND ALONG THE
NORTHERN FRINGES OF THE UPPER LEVEL RIDGE AXIS THAT EXTENDS FROM
TEXAS NORTH INTO THE CENTRAL PLAINS. THIS WAVE CRUISES THROUGH
SATURDAY MORNING WITH SURFACE HIGH PRESSURE IN PLACE AND A LACK OF
DEEPER MOISTURE...SO HAVE CONTINUED A DRY FORECAST...AND THAT GOES
FOR SATURDAY AFTERNOON AS WELL AS THE WAVE MOVES EAST. WILL HAVE
TO WATCH THE MORNING PERIOD IF THE LOWER LEVELS MOISTEN UP A BIT
MORE THAN FORECAST THAT A STRAY SHOWER OR STORM WOULD BE POSSIBLE.
THE NAM IS A LITTLE SLOWER WITH THIS WAVE...BUT STILL DRY IN THE
AFTERNOON AS THE STRONGER FORCING REMAINS TO OUR WEST.
CHANCES FOR SHOWERS AND STORMS INCREASE SATURDAY NIGHT INTO SUNDAY
MORNING AS WE GET A BETTER CO-LOCATION OF DEEPER MOISTURE TRANSPORT
COURTESY OF A DECENT LOW LEVEL JET...ANOTHER PACIFIC
DISTURBANCE...AND PWATS APPROACHING 2 INCHES. WE HANG ONTO SE FLOW
AT THE SURFACE FARTHER EAST...WHICH WOULD THEN GIVE THE HIGHER
CONCERN FOR MODERATE TO HEAVY PRECIP RATES SOUTH AND WEST. THERE
IS A SEVERE THREAT GIVEN THE MODEST WESTERLY FLOW NORTH OF THE
RIDGE AND HIGHER DEWPOINTS ADVECTING IN...BUT DESTABILIZATION
CONCERNS EXIST AT THIS POINT IN TIME TO NAIL DOWN THE SPECIFICS
YET. THE MARGINAL RISK IS FOCUSED IN OUR SOUTHWEST AT THIS TIME.
KMD
&&
.LONG TERM...
407 AM CDT
SUNDAY NIGHT THROUGH THURSDAY...
.LONG TERM...
AN UPPER LEVEL LOW QUICKLY MOVES EASTWARD THROUGH SOUTHERN ONTARIO SUNDAY
NIGHT INTO MONDAY...AS THIS OCCURS AND A DEEP TROUGH BUILDS ALONG
THE PACIFIC COAST...UPPER LEVEL RIDGING IN THE WEST WILL CONTINUE
TO AMPLIFY THE FLOW PATTERN. NW FLOW ON MONDAY WILL KEEP A CHANCE
FOR SHOWERS AND STORMS AROUND AS A WEAK COLD FRONT MOVES THROUGH.
ANOTHER DISTURBANCE GLIDES BY TO OUR NORTH TUESDAY FOR A SOMEWHAT
COOLER THOUGH GENERALLY DRY DAY. A STRAY SHOWER IS POSSIBLE. HIGH
PRESSURE BUILDS IN FOR MID WEEK.
KMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* LAKE BREEZE POTENTIAL THIS AFTERNOON.
* ISOLATED SHOWERS TONIGHT.
* BRIEF REDUCTION IN VSBY DUE TO FOG SATURDAY MORNING.
MM
//DISCUSSION...UPDATED 18Z...
TERMINAL DOPPLER RADAR INDICATES LAKE BREEZE BOUNDARY MAKING
INROADS TOWARD ORD EARLY THIS AFTERNOON. LOW LEVEL SOUTHWEST WINDS
HAVE BEEN COMBATING THIS WEAK BOUNDARY TODAY...AND IT DOES APPEAR
THAT THE BOUNDARY MAY REMAIN EAST OF ORD. THE RESULT LEAVES PREVAILING
SSW WINDS LIKELY. IF THE BOUNDARY WERE TO PENETRATE FURTHER...IT
WILL LIKELY BE AFTER A FEW MORE HOURS OF DAYTIME HEATING...NEAR
22Z.
OVERNIGHT A NON-STANDARD WARM FRONT WILL APPROACH THE
AREA...PROVIDING FOCUS FOR SOME SCATTERED SHOWERS. TAF SITES WILL
BE IN THE WARM SECTOR OF THE LOW IN THE MORNING WHICH WILL HELP
FORMATION OF FOG IN THE MORNING. THIS FRONT BECOMES NEARLY
STATIONARY EARLY SATURDAY. THE PRESSURE PATTERN WILL FAVOR WEAK
SOUTHERLY WINDS DURING THE DAY...VEERING TO BECOME NORTHWEST IN
THE LATE AFTERNOON. A LAKE BREEZE IS AGAIN POSSIBLE AFTER 22Z.
MM
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM-LOW IN LAKE BREEZE TODAY.
* MEDIUM IN SHOWERS TONIGHT.
* MEDIUM-LOW IN FOG DENSITY.
MM
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...SLIGHT CHANCE OF THUNDERSTORMS.
SUNDAY...CHANCE OF THUNDERSTORMS.
MONDAY...CHANCE OF THUNDERSTORMS.
TUESDAY...VFR.
WEDNESDAY...VFR.
THURSDAY...VFR.
RODRIGUEZ
&&
.MARINE...
302 AM CDT
LIGHTER EASTERLY WINDS IN PLACE EARLY THIS MORNING WILL OBSERVE A
STEADY INCREASE TODAY WHILE SHIFTING TO MORE OF A SOUTHERLY
COMPONENT...AS LOW PRESSURE TO THE WEST OVER THE NORTHERN PLAINS
SLOWLY PUSHES EAST. STILL THINK A 10 TO 20 KT WIND WILL BE THE
HIGHEST TODAY...BUT SOME GUIDANCE IS HINTING AT POSSIBLE HIGHER
SPEEDS THROUGHOUT THE DAY. ALTHOUGH I DID INCREASE SPEEDS...DID
NOT GO AS HIGH. HOWEVER...DID MENTION A FEW GUSTS TO 25KT FOR THE
OPEN WATERS TODAY. IT DOES LOOK LIKE A BETTER WINDOW FOR STRONGER
WINDS OF 15 TO 25 KT ACROSS THE NORTH TONIGHT INTO SATURDAY
MORNING...AND HAVE TRENDED THAT WAY WITH THE FORECAST. THIS WILL
BE IN RESPONSE TO THE APPROACHING LOW...BUT WITH IT
WEAKENING...SPEEDS WILL DIMINISH SATURDAY INTO SATURDAY NIGHT.
EXACT TIMING AND PLACEMENT OF THE NEXT SYSTEM LATE IN THE WEEKEND
IS STILL UNCERTAIN BUT IT DOES APPEAR TO BE ANOTHER PERIOD WHEN
SPEEDS WILL ONCE AGAIN INCREASE...AT LEAST FOR THE SOUTHERN HALF
OF THE LAKE.
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
1143 AM CDT FRI AUG 7 2015
.UPDATE...
1143 AM CDT
A WEAKENING SURFACE LOW RESIDES OVER FAR WESTERN WISCONSIN...WITH
HIGH PRESSURE CENTERED OVER THE EASTERN AND CENTRAL GREAT LAKES
LATE THIS MORNING. GLANCING BLOW FROM THE MID/UPPER WAVE
ASSOCIATED FROM THE SURFACE LOW THAT IS MAINLY FOCUSED INTO
WISCONSIN WILL GRADUALLY SPREAD ISOLATED TO WIDELY SCATTERED
SHOWERS/SPRINKLES EASTWARD IN NORTHERN ILLINOIS NORTH OF
INTERSTATE 80. WEAKER FORCING WITH SOUTHWARD EXTENT AND DRY LOWER
LEVELS NOTED ON 12Z DVN RAOB AND AIRCRAFT SOUNDINGS WILL KEEP
AREAL COVERAGE LOW. MANY AREAS WILL NOT SEE ANY MEASURABLE
RAINFALL GIVEN THE WEAK FORCING AND LOW AREAL COVERAGE. IN
ADDITION...POOR MIDLEVEL LAPSE RATES WILL LIMIT
DESTABILIZATION...WITH ML AND SB CAPE AXIS STAYING WEST OF THE
AREA THROUGH THE AFTERNOON. THERE COULD BE ENOUGH MUCAPE FOR
SLIGHT CHANCE OF THUNDER THIS AFTERNOON MAINLY NORTHWEST OF A
STERLING TO ANTIOCH LINE...THOUGH THIS COULD EVEN END UP BULLISH.
TEMPERATURES FROM INHERITED FORECAST HAVE BEEN TRACKING VERY WELL
WITH HOURLY OBS...SO HIGHS GENERALLY IN THE LOWER 80S APPEAR ON
TRACK...WITH MID 80S POSSIBLE IN CHICAGO HEAT ISLAND AWAY FROM
MINOR COOLING INFLUENCE OF LAKE BREEZE.
RC
&&
.SHORT TERM...
349 AM CDT
THROUGH SUNDAY...
CONCERNS REVOLVE AROUND PRECIPITATION CHANCES EACH OF THE NEXT FEW
DAYS.
A COMPACT BUT POTENT UPPER LEVEL DISTURBANCE IN MN IS PRODUCING A
COMPLEX OF THUNDERSTORMS NOW MOVING INTO WESTERN WISCONSIN. THERE IS
A WEAK SURFACE REFLECTION WITH THIS FEATURE WHERE THE MORE ORGANIZED
ACTIVITY IS ONGOING. CLOSER TO HOME...SURFACE HIGH PRESSURE IS
HOLDING FIRM JUST NEAR LAKE HURON...WITH THE RIDGE AXIS ORIENTED
SOUTHWESTWARD. IR IMAGERY EARLY THIS MORNING HAS SHOWN A CONTINUAL
EROSION OF THE DEEPER CLOUDS ON THE SOUTHERN END OF THIS COMPLEX AS
IT MOVES INTO DRIER AIR FARTHER SOUTH AND EAST.
AN UPPER LEVEL JET MOVING INTO THE NORTHERN PLAINS WILL ALLOW THIS
UPPER DISTURBANCE TO MOVE SOUTH AND EAST TOWARD THE AREA
TODAY...EVEN OUTRUNNING THE SURFACE LOW. MUCH OF THE NEAR TERM
GUIDANCE KEEPS ERODING PRECIP SOUTH OF THE WISCONSIN BORDER AHEAD OF
THIS SYSTEM. THE EXCEPTION TO THIS THE EXPERIMENTAL HRRR AND
SEVERAL HOP-WRF MEMBERS WHICH ARE A BIT MORE AGGRESSIVE WITH
DRIVING PRECIP THROUGH THE AREA...ESPECIALLY THIS AFTERNOON.
OBSERVATIONS SUGGEST SOME CONTINUED DEVELOPMENT SOUTHWARD THROUGH
THE MORNING INTO THE INSTABILITY AXIS WHICH WILL GRADUALLY
APPROACH FROM THE WEST TODAY. HAVE STILL KEPT POPS ON THE LOWER
SIDE AWAY FROM NORTH CENTRAL ILLINOIS AND POINTS WEST...THOUGH
EXPECT OUR NORTHWESTERN ZONES INTO WINNEBAGO/BOONE/MCHENRY
COUNTIES STAND A CHANCE OF SOME SHOWERS OR A STRAY STORM LATER
THIS MORNING INTO THE AFTERNOON. CONTINUED DRY AIR SHOULD FURTHER
ERODE AT THE PRECIP...THOUGH AS THE DAY GOES ON AND THE
INSTABILITY AXIS SHIFTS EASTWARD WITH THE UPPER LOW...EXPECT THAT
SOME SHOWERS WILL BE POSSIBLE. SOUNDINGS ARE NOT THRILLED ABOUT
THE THUNDER POTENTIAL CLOSER TO CHICAGO WITH CAPPING HOLDING.
TONIGHT...THE UPPER LOW SHIFTS EAST AND OUTPACES THE SURFACE LOW AND
THUS EXPECT SOME DECREASE IN COVERAGE OF SHOWERS AND COULD JUST BE
DRY...THOUGH WILL HANG ONTO A LOW POP MENTION OVERNIGHT FOR SOME
LINGERING LOW LEVEL CONVERGENCE.
SATURDAY...FOCUS SHIFTS TO ENERGY PROPAGATING FROM THE TROUGH OFF
THE CA COAST THIS MORNING. THIS IS FORECAST TO RIDE A DECENT UPPER
JET THROUGH THE PLAINS OVERNIGHT INTO THE MORNING AND ALONG THE
NORTHERN FRINGES OF THE UPPER LEVEL RIDGE AXIS THAT EXTENDS FROM
TEXAS NORTH INTO THE CENTRAL PLAINS. THIS WAVE CRUISES THROUGH
SATURDAY MORNING WITH SURFACE HIGH PRESSURE IN PLACE AND A LACK OF
DEEPER MOISTURE...SO HAVE CONTINUED A DRY FORECAST...AND THAT GOES
FOR SATURDAY AFTERNOON AS WELL AS THE WAVE MOVES EAST. WILL HAVE
TO WATCH THE MORNING PERIOD IF THE LOWER LEVELS MOISTEN UP A BIT
MORE THAN FORECAST THAT A STRAY SHOWER OR STORM WOULD BE POSSIBLE.
THE NAM IS A LITTLE SLOWER WITH THIS WAVE...BUT STILL DRY IN THE
AFTERNOON AS THE STRONGER FORCING REMAINS TO OUR WEST.
CHANCES FOR SHOWERS AND STORMS INCREASE SATURDAY NIGHT INTO SUNDAY
MORNING AS WE GET A BETTER CO-LOCATION OF DEEPER MOISTURE TRANSPORT
COURTESY OF A DECENT LOW LEVEL JET...ANOTHER PACIFIC
DISTURBANCE...AND PWATS APPROACHING 2 INCHES. WE HANG ONTO SE FLOW
AT THE SURFACE FARTHER EAST...WHICH WOULD THEN GIVE THE HIGHER
CONCERN FOR MODERATE TO HEAVY PRECIP RATES SOUTH AND WEST. THERE
IS A SEVERE THREAT GIVEN THE MODEST WESTERLY FLOW NORTH OF THE
RIDGE AND HIGHER DEWPOINTS ADVECTING IN...BUT DESTABILIZATION
CONCERNS EXIST AT THIS POINT IN TIME TO NAIL DOWN THE SPECIFICS
YET. THE MARGINAL RISK IS FOCUSED IN OUR SOUTHWEST AT THIS TIME.
KMD
&&
.LONG TERM...
407 AM CDT
SUNDAY NIGHT THROUGH THURSDAY...
.LONG TERM...
AN UPPER LEVEL LOW QUICKLY MOVES EASTWARD THROUGH SOUTHERN ONTARIO SUNDAY
NIGHT INTO MONDAY...AS THIS OCCURS AND A DEEP TROUGH BUILDS ALONG
THE PACIFIC COAST...UPPER LEVEL RIDGING IN THE WEST WILL CONTINUE
TO AMPLIFY THE FLOW PATTERN. NW FLOW ON MONDAY WILL KEEP A CHANCE
FOR SHOWERS AND STORMS AROUND AS A WEAK COLD FRONT MOVES THROUGH.
ANOTHER DISTURBANCE GLIDES BY TO OUR NORTH TUESDAY FOR A SOMEWHAT
COOLER THOUGH GENERALLY DRY DAY. A STRAY SHOWER IS POSSIBLE. HIGH
PRESSURE BUILDS IN FOR MID WEEK.
KMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* LAKE BREEZE TO EAST/SOUTHEAST WINDS THIS AFTERNOON.
* SLIGHT CHANCE OF SHOWERS THIS AFTERNOON INTO THE EVENING.
MM
//DISCUSSION...UPDATED 12Z...
VFR CONDITIONS PERSISTING THIS MORNING WHILE SOUTH/SOUTHEAST
WINDS STEADILY INCREASE. VFR CONDITIONS ARE STILL EXPECTED FOR
MOST OF THE FORECAST PERIOD. HOWEVER...THE POTENTIAL FOR SCATTERED
SHOWERS IS INCREASING AND BECOMING SOONER THAN PREVIOUSLY
EXPECTED. ALTHOUGH THE HIGHEST CHANCES FOR PRECIP WILL STAY TO
THE NORTH...AT LEAST SCATTERED DEVELOPMENT IS NOW POSSIBLE THIS
AFTERNOON INTO THE EARLY EVENING. INSTABILITY DOES NOT APPEAR TO
BE THE GREATEST...AND SO THINK THE LIKELIHOOD OF THUNDER IS LOW AT
THIS TIME. LAKE BREEZE PUSH IS STILL APPEARING TO BE LIKELY THIS
AFTERNOON...WITH EAST SOUTHEAST WINDS AT OR ABOVE 10KT EXPECTED
LATER THIS AFTERNOON.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* MEDIUM CONFIDENCE FOR WINDS/LAKE BREEZE TODAY.
* MEDIUM CONFIDENCE FOR ISOLATED SHOWERS.
MM
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...SLIGHT CHANCE OF THUNDERSTORMS.
SUNDAY...CHANCE OF THUNDERSTORMS.
MONDAY...CHANCE OF THUNDERSTORMS.
TUESDAY...VFR.
WEDNESDAY...VFR.
THURSDAY...VFR.
RODRIGUEZ
&&
.MARINE...
302 AM CDT
LIGHTER EASTERLY WINDS IN PLACE EARLY THIS MORNING WILL OBSERVE A
STEADY INCREASE TODAY WHILE SHIFTING TO MORE OF A SOUTHERLY
COMPONENT...AS LOW PRESSURE TO THE WEST OVER THE NORTHERN PLAINS
SLOWLY PUSHES EAST. STILL THINK A 10 TO 20 KT WIND WILL BE THE
HIGHEST TODAY...BUT SOME GUIDANCE IS HINTING AT POSSIBLE HIGHER
SPEEDS THROUGHOUT THE DAY. ALTHOUGH I DID INCREASE SPEEDS...DID
NOT GO AS HIGH. HOWEVER...DID MENTION A FEW GUSTS TO 25KT FOR THE
OPEN WATERS TODAY. IT DOES LOOK LIKE A BETTER WINDOW FOR STRONGER
WINDS OF 15 TO 25 KT ACROSS THE NORTH TONIGHT INTO SATURDAY
MORNING...AND HAVE TRENDED THAT WAY WITH THE FORECAST. THIS WILL
BE IN RESPONSE TO THE APPROACHING LOW...BUT WITH IT
WEAKENING...SPEEDS WILL DIMINISH SATURDAY INTO SATURDAY NIGHT.
EXACT TIMING AND PLACEMENT OF THE NEXT SYSTEM LATE IN THE WEEKEND
IS STILL UNCERTAIN BUT IT DOES APPEAR TO BE ANOTHER PERIOD WHEN
SPEEDS WILL ONCE AGAIN INCREASE...AT LEAST FOR THE SOUTHERN HALF
OF THE LAKE.
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
907 AM CDT FRI AUG 7 2015
.SHORT TERM...
349 AM CDT
THROUGH SUNDAY...
CONCERNS REVOLVE AROUND PRECIPITATION CHANCES EACH OF THE NEXT FEW
DAYS.
A COMPACT BUT POTENT UPPER LEVEL DISTURBANCE IN MN IS PRODUCING A
COMPLEX OF THUNDERSTORMS NOW MOVING INTO WESTERN WISCONSIN. THERE IS
A WEAK SURFACE REFLECTION WITH THIS FEATURE WHERE THE MORE ORGANIZED
ACTIVITY IS ONGOING. CLOSER TO HOME...SURFACE HIGH PRESSURE IS
HOLDING FIRM JUST NEAR LAKE HURON...WITH THE RIDGE AXIS ORIENTED
SOUTHWESTWARD. IR IMAGERY EARLY THIS MORNING HAS SHOWN A CONTINUAL
EROSION OF THE DEEPER CLOUDS ON THE SOUTHERN END OF THIS COMPLEX AS
IT MOVES INTO DRIER AIR FARTHER SOUTH AND EAST.
AN UPPER LEVEL JET MOVING INTO THE NORTHERN PLAINS WILL ALLOW THIS
UPPER DISTURBANCE TO MOVE SOUTH AND EAST TOWARD THE AREA
TODAY...EVEN OUTRUNNING THE SURFACE LOW. MUCH OF THE NEAR TERM
GUIDANCE KEEPS ERODING PRECIP SOUTH OF THE WISCONSIN BORDER AHEAD OF
THIS SYSTEM. THE EXCEPTION TO THIS THE EXPERIMENTAL HRRR AND
SEVERAL HOP-WRF MEMBERS WHICH ARE A BIT MORE AGGRESSIVE WITH
DRIVING PRECIP THROUGH THE AREA...ESPECIALLY THIS AFTERNOON.
OBSERVATIONS SUGGEST SOME CONTINUED DEVELOPMENT SOUTHWARD THROUGH
THE MORNING INTO THE INSTABILITY AXIS WHICH WILL GRADUALLY
APPROACH FROM THE WEST TODAY. HAVE STILL KEPT POPS ON THE LOWER
SIDE AWAY FROM NORTH CENTRAL ILLINOIS AND POINTS WEST...THOUGH
EXPECT OUR NORTHWESTERN ZONES INTO WINNEBAGO/BOONE/MCHENRY
COUNTIES STAND A CHANCE OF SOME SHOWERS OR A STRAY STORM LATER
THIS MORNING INTO THE AFTERNOON. CONTINUED DRY AIR SHOULD FURTHER
ERODE AT THE PRECIP...THOUGH AS THE DAY GOES ON AND THE
INSTABILITY AXIS SHIFTS EASTWARD WITH THE UPPER LOW...EXPECT THAT
SOME SHOWERS WILL BE POSSIBLE. SOUNDINGS ARE NOT THRILLED ABOUT
THE THUNDER POTENTIAL CLOSER TO CHICAGO WITH CAPPING HOLDING.
TONIGHT...THE UPPER LOW SHIFTS EAST AND OUTPACES THE SURFACE LOW AND
THUS EXPECT SOME DECREASE IN COVERAGE OF SHOWERS AND COULD JUST BE
DRY...THOUGH WILL HANG ONTO A LOW POP MENTION OVERNIGHT FOR SOME
LINGERING LOW LEVEL CONVERGENCE.
SATURDAY...FOCUS SHIFTS TO ENERGY PROPAGATING FROM THE TROUGH OFF
THE CA COAST THIS MORNING. THIS IS FORECAST TO RIDE A DECENT UPPER
JET THROUGH THE PLAINS OVERNIGHT INTO THE MORNING AND ALONG THE
NORTHERN FRINGES OF THE UPPER LEVEL RIDGE AXIS THAT EXTENDS FROM
TEXAS NORTH INTO THE CENTRAL PLAINS. THIS WAVE CRUISES THROUGH
SATURDAY MORNING WITH SURFACE HIGH PRESSURE IN PLACE AND A LACK OF
DEEPER MOISTURE...SO HAVE CONTINUED A DRY FORECAST...AND THAT GOES
FOR SATURDAY AFTERNOON AS WELL AS THE WAVE MOVES EAST. WILL HAVE
TO WATCH THE MORNING PERIOD IF THE LOWER LEVELS MOISTEN UP A BIT
MORE THAN FORECAST THAT A STRAY SHOWER OR STORM WOULD BE POSSIBLE.
THE NAM IS A LITTLE SLOWER WITH THIS WAVE...BUT STILL DRY IN THE
AFTERNOON AS THE STRONGER FORCING REMAINS TO OUR WEST.
CHANCES FOR SHOWERS AND STORMS INCREASE SATURDAY NIGHT INTO SUNDAY
MORNING AS WE GET A BETTER CO-LOCATION OF DEEPER MOISTURE TRANSPORT
COURTESY OF A DECENT LOW LEVEL JET...ANOTHER PACIFIC
DISTURBANCE...AND PWATS APPROACHING 2 INCHES. WE HANG ONTO SE FLOW
AT THE SURFACE FARTHER EAST...WHICH WOULD THEN GIVE THE HIGHER
CONCERN FOR MODERATE TO HEAVY PRECIP RATES SOUTH AND WEST. THERE
IS A SEVERE THREAT GIVEN THE MODEST WESTERLY FLOW NORTH OF THE
RIDGE AND HIGHER DEWPOINTS ADVECTING IN...BUT DESTABILIZATION
CONCERNS EXIST AT THIS POINT IN TIME TO NAIL DOWN THE SPECIFICS
YET. THE MARGINAL RISK IS FOCUSED IN OUR SOUTHWEST AT THIS TIME.
KMD
&&
.LONG TERM...
407 AM CDT
SUNDAY NIGHT THROUGH THURSDAY...
.LONG TERM...
AN UPPER LEVEL LOW QUICKLY MOVES EASTWARD THROUGH SOUTHERN ONTARIO SUNDAY
NIGHT INTO MONDAY...AS THIS OCCURS AND A DEEP TROUGH BUILDS ALONG
THE PACIFIC COAST...UPPER LEVEL RIDGING IN THE WEST WILL CONTINUE
TO AMPLIFY THE FLOW PATTERN. NW FLOW ON MONDAY WILL KEEP A CHANCE
FOR SHOWERS AND STORMS AROUND AS A WEAK COLD FRONT MOVES THROUGH.
ANOTHER DISTURBANCE GLIDES BY TO OUR NORTH TUESDAY FOR A SOMEWHAT
COOLER THOUGH GENERALLY DRY DAY. A STRAY SHOWER IS POSSIBLE. HIGH
PRESSURE BUILDS IN FOR MID WEEK.
KMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* LAKE BREEZE TO EAST/SOUTHEAST WINDS THIS AFTERNOON.
* SLIGHT CHANCE OF SHOWERS THIS AFTERNOON INTO THE EVENING.
MM
//DISCUSSION...UPDATED 12Z...
VFR CONDITIONS PERSISTING THIS MORNING WHILE SOUTH/SOUTHEAST
WINDS STEADILY INCREASE. VFR CONDITIONS ARE STILL EXPECTED FOR
MOST OF THE FORECAST PERIOD. HOWEVER...THE POTENTIAL FOR SCATTERED
SHOWERS IS INCREASING AND BECOMING SOONER THAN PREVIOUSLY
EXPECTED. ALTHOUGH THE HIGHEST CHANCES FOR PRECIP WILL STAY TO
THE NORTH...AT LEAST SCATTERED DEVELOPMENT IS NOW POSSIBLE THIS
AFTERNOON INTO THE EARLY EVENING. INSTABILITY DOES NOT APPEAR TO
BE THE GREATEST...AND SO THINK THE LIKELIHOOD OF THUNDER IS LOW AT
THIS TIME. LAKE BREEZE PUSH IS STILL APPEARING TO BE LIKELY THIS
AFTERNOON...WITH EAST SOUTHEAST WINDS AT OR ABOVE 10KT EXPECTED
LATER THIS AFTERNOON.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* MEDIUM CONFIDENCE FOR WINDS/LAKE BREEZE TODAY.
* MEDIUM CONFIDENCE FOR ISOLATED SHOWERS.
MM
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...SLIGHT CHANCE OF THUNDERSTORMS.
SUNDAY...CHANCE OF THUNDERSTORMS.
MONDAY...CHANCE OF THUNDERSTORMS.
TUESDAY...VFR.
WEDNESDAY...VFR.
THURSDAY...VFR.
RODRIGUEZ
&&
.MARINE...
302 AM CDT
LIGHTER EASTERLY WINDS IN PLACE EARLY THIS MORNING WILL OBSERVE A
STEADY INCREASE TODAY WHILE SHIFTING TO MORE OF A SOUTHERLY
COMPONENT...AS LOW PRESSURE TO THE WEST OVER THE NORTHERN PLAINS
SLOWLY PUSHES EAST. STILL THINK A 10 TO 20 KT WIND WILL BE THE
HIGHEST TODAY...BUT SOME GUIDANCE IS HINTING AT POSSIBLE HIGHER
SPEEDS THROUGHOUT THE DAY. ALTHOUGH I DID INCREASE SPEEDS...DID
NOT GO AS HIGH. HOWEVER...DID MENTION A FEW GUSTS TO 25KT FOR THE
OPEN WATERS TODAY. IT DOES LOOK LIKE A BETTER WINDOW FOR STRONGER
WINDS OF 15 TO 25 KT ACROSS THE NORTH TONIGHT INTO SATURDAY
MORNING...AND HAVE TRENDED THAT WAY WITH THE FORECAST. THIS WILL
BE IN RESPONSE TO THE APPROACHING LOW...BUT WITH IT
WEAKENING...SPEEDS WILL DIMINISH SATURDAY INTO SATURDAY NIGHT.
EXACT TIMING AND PLACEMENT OF THE NEXT SYSTEM LATE IN THE WEEKEND
IS STILL UNCERTAIN BUT IT DOES APPEAR TO BE ANOTHER PERIOD WHEN
SPEEDS WILL ONCE AGAIN INCREASE...AT LEAST FOR THE SOUTHERN HALF
OF THE LAKE.
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
642 AM CDT FRI AUG 7 2015
.SHORT TERM...
349 AM CDT
THROUGH SUNDAY...
CONCERNS REVOLVE AROUND PRECIPITATION CHANCES EACH OF THE NEXT FEW
DAYS.
A COMPACT BUT POTENT UPPER LEVEL DISTURBANCE IN MN IS PRODUCING A
COMPLEX OF THUNDERSTORMS NOW MOVING INTO WESTERN WISCONSIN. THERE IS
A WEAK SURFACE REFLECTION WITH THIS FEATURE WHERE THE MORE ORGANIZED
ACTIVITY IS ONGOING. CLOSER TO HOME...SURFACE HIGH PRESSURE IS
HOLDING FIRM JUST NEAR LAKE HURON...WITH THE RIDGE AXIS ORIENTED
SOUTHWESTWARD. IR IMAGERY EARLY THIS MORNING HAS SHOWN A CONTINUAL
EROSION OF THE DEEPER CLOUDS ON THE SOUTHERN END OF THIS COMPLEX AS
IT MOVES INTO DRIER AIR FARTHER SOUTH AND EAST.
AN UPPER LEVEL JET MOVING INTO THE NORTHERN PLAINS WILL ALLOW THIS
UPPER DISTURBANCE TO MOVE SOUTH AND EAST TOWARD THE AREA
TODAY...EVEN OUTRUNNING THE SURFACE LOW. MUCH OF THE NEAR TERM
GUIDANCE KEEPS ERODING PRECIP SOUTH OF THE WISCONSIN BORDER AHEAD OF
THIS SYSTEM. THE EXCEPTION TO THIS THE EXPERIMENTAL HRRR AND
SEVERAL HOP-WRF MEMBERS WHICH ARE A BIT MORE AGGRESSIVE WITH
DRIVING PRECIP THROUGH THE AREA...ESPEICALLY THIS AFTERNOON.
OBSERVATIONS SUGGEST SOME CONTINUED DEVELOPMENT SOUTHWARD THROUGH
THE MORNING INTO THE INSTABILITY AXIS WHICH WILL GRADUALLY
APPROACH FROM THE WEST TODAY. HAVE STILL KEPT POPS ON THE LOWER
SIDE AWAY FROM NORTH CENTRAL ILLINOIS AND POINTS WEST...THOUGH
EXPECT OUR NORTHWESTERN ZONES INTO WINNEBAGO/BOONE/MCHENRY
COUNTIES STAND A CHANCE OF SOME SHOWERS OR A STRAY STORM LATER
THIS MORNING INTO THE AFTERNOON. CONTINUED DRY AIR SHOULD FURTHER
ERODE AT THE PRECIP...THOUGH AS THE DAY GOES ON AND THE
INSTABILITY AXIS SHIFTS EASTWARD WITH THE UPPER LOW...EXPECT THAT
SOME SHOWERS WILL BE POSSIBLE. SOUNDINGS ARE NOT THRILLED ABOUT
THE THUNDER POTENTIAL CLOSER TO CHICAGO WITH CAPPING HOLDING.
TONIGHT...THE UPPER LOW SHIFTS EAST AND OUTPACES THE SURFACE LOW AND
THUS EXPECT SOME DECREASE IN COVERAGE OF SHOWERS AND COULD JUST BE
DRY...THOUGH WILL HANG ONTO A LOW POP MENTION OVERNIGHT FOR SOME
LINGERING LOW LEVEL CONVERGENCE.
SATURDAY...FOCUS SHIFTS TO ENERGY PROPAGATING FROM THE TROUGH OFF
THE CA COAST THIS MORNING. THIS IS FORECAST TO RIDE A DECENT UPPER
JET THROUGH THE PLAINS OVERNIGHT INTO THE MORNING AND ALONG THE
NORTHERN FRINGES OF THE UPPER LEVEL RIDGE AXIS THAT EXTENDS FROM
TEXAS NORTH INTO THE CENTRAL PLAINS. THIS WAVE CRUISES THROUGH
SATURDAY MORNING WITH SURFACE HIGH PRESSURE IN PLACE AND A LACK OF
DEEPER MOISTURE...SO HAVE CONTINUED A DRY FORECAST...AND THAT GOES
FOR SATURDAY AFTERNOON AS WELL AS THE WAVE MOVES EAST. WILL HAVE
TO WATCH THE MORNING PERIOD IF THE LOWER LEVELS MOISTEN UP A BIT
MORE THAN FORECAST THAT A STRAY SHOWER OR STORM WOULD BE POSSIBLE.
THE NAM IS A LITTLE SLOWER WITH THIS WAVE...BUT STILL DRY IN THE
AFTERNOON AS THE STRONGER FORCING REMAINS TO OUR WEST.
CHANCES FOR SHOWERS AND STORMS INCREASE SATURDAY NIGHT INTO SUNDAY
MORNING AS WE GET A BETTER CO-LOCATION OF DEEPER MOISTURE TRANSPORT
COURTESY OF A DECENT LOW LEVEL JET...ANOTHER PACIFIC
DISTURBANCE...AND PWATS APPROACHING 2 INCHES. WE HANG ONTO SE FLOW
AT THE SURFACE FARTHER EAST...WHICH WOULD THEN GIVE THE HIGHER
CONCERN FOR MODERATE TO HEAVY PRECIP RATES SOUTH AND WEST. THERE
IS A SEVERE THREAT GIVEN THE MODEST WESTERLY FLOW NORTH OF THE
RIDGE AND HIGHER DEWPOINTS ADVECTING IN...BUT DESTABILIZATION
CONCERNS EXIST AT THIS POINT IN TIME TO NAIL DOWN THE SPECIFICS
YET. THE MARGINAL RISK IS FOCUSED IN OUR SOUTHWEST AT THIS TIME.
KMD
&&
.LONG TERM...
407 AM CDT
SUNDAY NIGHT THROUGH THURSDAY...
.LONG TERM...
AN UPPER LEVEL LOW QUICKLY MOVES EASTWARD THROUGH SOUTHERN ONTARIO SUNDAY
NIGHT INTO MONDAY...AS THIS OCCURS AND A DEEP TROUGH BUILDS ALONG
THE PACIFIC COAST...UPPER LEVEL RIDGING IN THE WEST WILL CONTINUE
TO AMPLIFY THE FLOW PATTTERN. NW FLOW ON MONDAY WILL KEEP A CHANCE
FOR SHOWERS AND STORMS AROUND AS A WEAK COLD FRONT MOVES THROUGH.
ANOTHER DISTURBANCE GLIDES BY TO OUR NORTH TUESDAY FOR A SOMEWHAT
COOLER THORUGH GENERALLY DRY DAY. A STRAY SHOWER IS POSSIBLE. HIGH
PRESSURE BUILDS IN FOR MID WEEK.
KMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* LAKE BREEZE/SHIFT TO EAST/SOUTHEAST WINDS THIS AFTERNOON.
* POSSIBLE SCATTERED SHOWERS THIS AFTERNOON INTO THE EVENING.
RODRIGUEZ
//DISCUSSION...UPDATED 12Z...
VFR CONDITIONS PERSISTING THIS MORNING WHILE SOUTH/SOUTHEAST
WINDS STEADILY INCREASE. VFR CONDITIONS ARE STILL EXPECTED FOR
MOST OF THE FORECAST PERIOD. HOWEVER...THE POTENTIAL FOR SCATTERED
SHOWERS IS INCREASING AND BECOMING SOONER THAN PREVIOUSLY
EXPECTED. ALTHOUGH THE HIGHEST CHANCES FOR PREIP WILL STAY TO THE
NORTH...AT LEAST SCATTERED DEVELOPMENT IS NOW POSSIBLE THIS
AFTERNOON INTO THE EARLY EVENING. INSTABILITY DOES NOT APPEAR TO
BE THE GREATEST...AND SO THINK THE LIKELIHOOD OF THUNDER IS LOW
AT THIS TIME. LAKE BREEZE PUSH IS STILL APPEARING TO BE LIKELY
THIS AFTERNOON...WITH EAST SOUTHEAST WINDS AT OR ABOVE 10KT
EXPECTED LATER THIS AFTERNOON.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* MEDIUM CONFIDENCE FOR WINDS/LAKE BREEZE TODAY.
* MEDIUM CONFIDENCE FOR SCATTERED SHOWERS.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...SLIGHT CHANCE OF THUNDERSTORMS.
SUNDAY...CHANCE OF THUNDERSTORMS.
MONDAY...CHANCE OF THUNDERSTORMS.
TUESDAY...VFR.
WEDNESDAY...VFR.
THURSDAY...VFR.
RODRIGUEZ
&&
.MARINE...
302 AM CDT
LIGHTER EASTERLY WINDS IN PLACE EARLY THIS MORNING WILL OBSERVE A
STEADY INCREASE TODAY WHILE SHIFTING TO MORE OF A SOUTHERLY
COMPONENT...AS LOW PRESSURE TO THE WEST OVER THE NORTHERN PLAINS
SLOWLY PUSHES EAST. STILL THINK A 10 TO 20 KT WIND WILL BE THE
HIGHEST TODAY...BUT SOME GUIDANCE IS HINTING AT POSSIBLE HIGHER
SPEEDS THROUGHOUT THE DAY. ALTHOUGH I DID INCREASE SPEEDS...DID
NOT GO AS HIGH. HOWEVER...DID MENTION A FEW GUSTS TO 25KT FOR THE
OPEN WATERS TODAY. IT DOES LOOK LIKE A BETTER WINDOW FOR STRONGER
WINDS OF 15 TO 25 KT ACROSS THE NORTH TONIGHT INTO SATURDAY
MORNING...AND HAVE TRENDED THAT WAY WITH THE FORECAST. THIS WILL
BE IN RESPONSE TO THE APPROACHING LOW...BUT WITH IT
WEAKENING...SPEEDS WILL DIMINISH SATURDAY INTO SATURDAY NIGHT.
EXACT TIMING AND PLACEMENT OF THE NEXT SYSTEM LATE IN THE WEEKEND
IS STILL UNCERTAIN BUT IT DOES APPEAR TO BE ANOTHER PERIOD WHEN
SPEEDS WILL ONCE AGAIN INCREASE...AT LEAST FOR THE SOUTHERN HALF
OF THE LAKE.
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
413 AM CDT FRI AUG 7 2015
.SHORT TERM...
349 AM CDT
THROUGH SUNDAY...
CONCERNS REVOLVE AROUND PRECIPITATION CHANCES EACH OF THE NEXT FEW
DAYS.
A COMPACT BUT POTENT UPPER LEVEL DISTURBANCE IN MN IS PRODUCING A
COMPLEX OF THUNDERSTORMS NOW MOVING INTO WESTERN WISCONSIN. THERE IS
A WEAK SURFACE REFLECTION WITH THIS FEATURE WHERE THE MORE ORGANIZED
ACTIVITY IS ONGOING. CLOSER TO HOME...SURFACE HIGH PRESSURE IS
HOLDING FIRM JUST NEAR LAKE HURON...WITH THE RIDGE AXIS ORIENTED
SOUTHWESTWARD. IR IMAGERY EARLY THIS MORNING HAS SHOWN A CONTINUAL
EROSION OF THE DEEPER CLOUDS ON THE SOUTHERN END OF THIS COMPLEX AS
IT MOVES INTO DRIER AIR FARTHER SOUTH AND EAST.
AN UPPER LEVEL JET MOVING INTO THE NORTHERN PLAINS WILL ALLOW THIS
UPPER DISTURBANCE TO MOVE SOUTH AND EAST TOWARD THE AREA
TODAY...EVEN OUTRUNNING THE SURFACE LOW. MUCH OF THE NEAR TERM
GUIDANCE KEEPS ERODING PRECIP SOUTH OF THE WISCONSIN BORDER AHEAD OF
THIS SYSTEM. THE EXCEPTION TO THIS THE EXPERIMENTAL HRRR AND
SEVERAL HOP-WRF MEMBERS WHICH ARE A BIT MORE AGGRESSIVE WITH
DRIVING PRECIP THROUGH THE AREA...ESPEICALLY THIS AFTERNOON.
OBSERVATIONS SUGGEST SOME CONTINUED DEVELOPMENT SOUTHWARD THROUGH
THE MORNING INTO THE INSTABILITY AXIS WHICH WILL GRADUALLY
APPROACH FROM THE WEST TODAY. HAVE STILL KEPT POPS ON THE LOWER
SIDE AWAY FROM NORTH CENTRAL ILLINOIS AND POINTS WEST...THOUGH
EXPECT OUR NORTHWESTERN ZONES INTO WINNEBAGO/BOONE/MCHENRY
COUNTIES STAND A CHANCE OF SOME SHOWERS OR A STRAY STORM LATER
THIS MORNING INTO THE AFTERNOON. CONTINUED DRY AIR SHOULD FURTHER
ERODE AT THE PRECIP...THOUGH AS THE DAY GOES ON AND THE
INSTABILITY AXIS SHIFTS EASTWARD WITH THE UPPER LOW...EXPECT THAT
SOME SHOWERS WILL BE POSSIBLE. SOUNDINGS ARE NOT THRILLED ABOUT
THE THUNDER POTENTIAL CLOSER TO CHICAGO WITH CAPPING HOLDING.
TONIGHT...THE UPPER LOW SHIFTS EAST AND OUTPACES THE SURFACE LOW AND
THUS EXPECT SOME DECREASE IN COVERAGE OF SHOWERS AND COULD JUST BE
DRY...THOUGH WILL HANG ONTO A LOW POP MENTION OVERNIGHT FOR SOME
LINGERING LOW LEVEL CONVERGENCE.
SATURDAY...FOCUS SHIFTS TO ENERGY PROPAGATING FROM THE TROUGH OFF
THE CA COAST THIS MORNING. THIS IS FORECAST TO RIDE A DECENT UPPER
JET THROUGH THE PLAINS OVERNIGHT INTO THE MORNING AND ALONG THE
NORTHERN FRINGES OF THE UPPER LEVEL RIDGE AXIS THAT EXTENDS FROM
TEXAS NORTH INTO THE CENTRAL PLAINS. THIS WAVE CRUISES THROUGH
SATURDAY MORNING WITH SURFACE HIGH PRESSURE IN PLACE AND A LACK OF
DEEPER MOISTURE...SO HAVE CONTINUED A DRY FORECAST...AND THAT GOES
FOR SATURDAY AFTERNOON AS WELL AS THE WAVE MOVES EAST. WILL HAVE
TO WATCH THE MORNING PERIOD IF THE LOWER LEVELS MOISTEN UP A BIT
MORE THAN FORECAST THAT A STRAY SHOWER OR STORM WOULD BE POSSIBLE.
THE NAM IS A LITTLE SLOWER WITH THIS WAVE...BUT STILL DRY IN THE
AFTERNOON AS THE STRONGER FORCING REMAINS TO OUR WEST.
CHANCES FOR SHOWERS AND STORMS INCREASE SATURDAY NIGHT INTO SUNDAY
MORNING AS WE GET A BETTER CO-LOCATION OF DEEPER MOISTURE TRANSPORT
COURTESY OF A DECENT LOW LEVEL JET...ANOTHER PACIFIC
DISTURBANCE...AND PWATS APPROACHING 2 INCHES. WE HANG ONTO SE FLOW
AT THE SURFACE FARTHER EAST...WHICH WOULD THEN GIVE THE HIGHER
CONCERN FOR MODERATE TO HEAVY PRECIP RATES SOUTH AND WEST. THERE
IS A SEVERE THREAT GIVEN THE MODEST WESTERLY FLOW NORTH OF THE
RIDGE AND HIGHER DEWPOINTS ADVECTING IN...BUT DESTABILIZATION
CONCERNS EXIST AT THIS POINT IN TIME TO NAIL DOWN THE SPECIFICS
YET. THE MARGINAL RISK IS FOCUSED IN OUR SOUTHWEST AT THIS TIME.
KMD
&&
.LONG TERM...
407 AM CDT
SUNDAY NIGHT THROUGH THURSDAY...
.LONG TERM...
AN UPPER LEVEL LOW QUICKLY MOVES EASTWARD THROUGH SOUTHERN ONTARIO SUNDAY
NIGHT INTO MONDAY...AS THIS OCCURS AND A DEEP TROUGH BUILDS ALONG
THE PACIFIC COAST...UPPER LEVEL RIDGING IN THE WEST WILL CONTINUE
TO AMPLIFY THE FLOW PATTTERN. NW FLOW ON MONDAY WILL KEEP A CHANCE
FOR SHOWERS AND STORMS AROUND AS A WEAK COLD FRONT MOVES THROUGH.
ANOTHER DISTURBANCE GLIDES BY TO OUR NORTH TUESDAY FOR A SOMEWHAT
COOLER THORUGH GENERALLY DRY DAY. A STRAY SHOWER IS POSSIBLE. HIGH
PRESSURE BUILDS IN FOR MID WEEK.
KMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* LAKE BREEZE/SHIFT TO EAST/SOUTHEAST WINDS THIS AFTERNOON.
* POSSIBLE SCATTERED SHOWERS LATE IN THE FORECAST PERIOD.
RODRIGUEZ
//DISCUSSION...UPDATED 06Z...
VFR CONDITIONS IN PLACE EARLY THIS MORNING...WITH LIGHT WINDS AND
ONLY HIGH LEVEL CLOUD COVER IN PLACE. VFR CONDITIONS ARE EXPECTED
MOST OF THE FORECAST PERIOD...WHILE SOUTHERLY WINDS STEADILY
INCREASE LATER THIS MORNING. MONITORING SHOWERS/THUNDERSTORMS TO
THE NORTHWEST MOVING THROUGH PORTIONS OF IOWA AND
WISCONSIN...LIKELY CONTINUING EAST THIS MORNING.
HOWEVER...SOUTHERN EXTENT OF THIS PRECIP SHIELD WILL LIKELY ERODE
KEEPING DRY CONDITIONS ACROSS THE TERMINALS THROUGH MIDDAY. THIS
SYSTEM/FRONT WILL SHIFT EAST LATER TODAY WITH ADDITIONAL SHOWERS
AND THUNDERSTORMS LIKELY PUSHING TOWARDS THE TERMINALS IN THE
AFTERNOON...WITH RFD HAVING THE HIGHER CHANCES OF OBSERVING THIS
PRECIP. THE REMAINING TERMINALS WILL THEN HAVE THESE HIGHER
CHANCES BY THE EVENING. WITH SOME POTENTIAL FOR THIS PRECIP TO
STAY NORTH THIS EVENING...HAVE EXCLUDED ANY MENTION FOR THE OTHER
TERMINALS AT THIS TIME.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* MEDIUM CONFIDENCE FOR WINDS/LAKE BREEZE TODAY.
* LOW MEDIUM CONFIDENCE FOR SHOWERS.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
* SATURDAY...DRY/VFR. SOUTHEAST WINDS.
* SUNDAY...CHANCE OF SHRA/TSRA. SOUTHEAST WINDS.
* MONDAY...CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* TUESDAY AND WEDNESDAY...DRY/VFR. NORTH/NORTHEAST WINDS.
&&
.MARINE...
302 AM CDT
LIGHTER EASTERLY WINDS IN PLACE EARLY THIS MORNING WILL OBSERVE A
STEADY INCREASE TODAY WHILE SHIFTING TO MORE OF A SOUTHERLY
COMPONENT...AS LOW PRESSURE TO THE WEST OVER THE NORTHERN PLAINS
SLOWLY PUSHES EAST. STILL THINK A 10 TO 20 KT WIND WILL BE THE
HIGHEST TODAY...BUT SOME GUIDANCE IS HINTING AT POSSIBLE HIGHER
SPEEDS THROUGHOUT THE DAY. ALTHOUGH I DID INCREASE SPEEDS...DID
NOT GO AS HIGH. HOWEVER...DID MENTION A FEW GUSTS TO 25KT FOR THE
OPEN WATERS TODAY. IT DOES LOOK LIKE A BETTER WINDOW FOR STRONGER
WINDS OF 15 TO 25 KT ACROSS THE NORTH TONIGHT INTO SATURDAY
MORNING...AND HAVE TRENDED THAT WAY WITH THE FORECAST. THIS WILL
BE IN RESPONSE TO THE APPROACHING LOW...BUT WITH IT
WEAKENING...SPEEDS WILL DIMINISH SATURDAY INTO SATURDAY NIGHT.
EXACT TIMING AND PLACEMENT OF THE NEXT SYSTEM LATE IN THE WEEKEND
IS STILL UNCERTAIN BUT IT DOES APPEAR TO BE ANOTHER PERIOD WHEN
SPEEDS WILL ONCE AGAIN INCREASE...AT LEAST FOR THE SOUTHERN HALF
OF THE LAKE.
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
353 AM CDT FRI AUG 7 2015
.SHORT TERM...
349 AM CDT
THROUGH SUNDAY...
CONCERNS REVOLVE AROUND PRECIPITATION CHANCES EACH OF THE NEXT FEW
DAYS.
A COMPACT BUT POTENT UPPER LEVEL DISTURBANCE IN MN IS PRODUCING A
COMPLEX OF THUNDERSTORMS NOW MOVING INTO WESTERN WISCONSIN. THERE IS
A WEAK SURFACE REFLECTION WITH THIS FEATURE WHERE THE MORE ORGANIZED
ACTIVITY IS ONGOING. CLOSER TO HOME...SURFACE HIGH PRESSURE IS
HOLDING FIRM JUST NEAR LAKE HURON...WITH THE RIDGE AXIS ORIENTED
SOUTHWESTWARD. IR IMAGERY EARLY THIS MORNING HAS SHOWN A CONTINUAL
EROSION OF THE DEEPER CLOUDS ON THE SOUTHERN END OF THIS COMPLEX AS
IT MOVES INTO DRIER AIR FARTHER SOUTH AND EAST.
AN UPPER LEVEL JET MOVING INTO THE NORTHERN PLAINS WILL ALLOW THIS
UPPER DISTURBANCE TO MOVE SOUTH AND EAST TOWARD THE AREA
TODAY...EVEN OUTRUNNING THE SURFACE LOW. MUCH OF THE NEAR TERM
GUIDANCE KEEPS ERODING PRECIP SOUTH OF THE WISCONSIN BORDER AHEAD OF
THIS SYSTEM. THE EXCEPTION TO THIS THE EXPERIMENTAL HRRR AND SEVERAL
HOP-WRF MEMBERS WHICH ARE QUITE A BIT MORE AGGRESSIVE WITH DRIVING
PRECIP THROUGH THE AREA LATER THIS MORNING/EARLY AFTERNOON.
OBSERVATIONS SUGGEST SOME CONTINUED DEVELOPMENT SOUTHWARD THROUGH
THE MORNING INTO THE INSTABILITY AXIS WHICH WILL GRADUALLY APPROACH
FROM THE WEST TODAY. HAVE STILL KEPT POPS ON THE LOWER SIDE AWAY
FROM NORTH CENTRAL ILLINOIS AND POINTS WEST...THOUGH EXPECT OUR
NORTHWESTERN ZONES INTO WINNEBAGO/BOONE/MCHENRY COUNTIES STAND A
DECENT CHANCE OF SOME SHOWERS AND THUNDERSTORMS LATER THIS MORNING
INTO THE AFTERNOON. CONTINUED DRY AIR SHOULD FURTHER ERODE AT THE
PRECIP...THOUGH AS THE DAY GOES ON AND THE INSTABILITY AXIS SHIFTS
EASTWARD WITH THE UPPER LOW...EXPECT THAT SOME SHOWERS WILL
AROUND...WITH THE BETTER CHANCE FOR A STORM IN NORTH CENTRAL
ILLINOIS.
TONIGHT...THE UPPER LOW SHIFTS EAST AND OUTPACES THE SURFACE LOW AND
THUS EXPECT SOME DECREASE IN COVERAGE OF SHOWERS...THOUGH WILL HANG
ONTO A LOW POP MENTION OVERNIGHT FOR SOME LINGERING LOW LEVEL
CONVERGENCE.
SATURDAY...FOCUS SHIFTS TO ENERGY PROPAGATING FROM THE TROUGH OFF
THE CA COAST THIS MORNING. THIS IS FORECAST TO RIDE A DECENT UPPER
JET THROUGH THE PLAINS OVERNIGHT INTO THE MORNING AND ALONG THE
NORTHERN FRINGES OF THE UPPER LEVEL RIDGE AXIS THAT EXTENDS FROM
TEXAS NORTH INTO THE CENTRAL PLAINS. THIS WAVES CRUISES THROUGH
SATURDAY MORNING WITH SURFACE HIGH PRESSURE IN PLACE AND A LACK OF
DEEPER MOISTURE...SO HAVE CONTINUED A DRY FORECAST...AND THAT GOES
FOR SATURDAY AFTERNOON AS WELL AS THE WAVE MOVES EAST. WILL HAVE TO
WATCH THE MORNING PERIOD IF THE LOWER LEVELS MOISTEN UP A BIT MORE
THAN FORECAST THAT A STRAY SHOWER OR STORM WOULD BE POSSIBLE. THE
NAM IS A LITTLE SLOWER WITH THIS WAVE...BUT STILL DRY IN THE
AFTERNOON AS THE STRONGER FORCING REMAINS TO OUR WEST.
CHANCES FOR SHOWERS AND STORMS INCREASE SATURDAY NIGHT INTO SUNDAY
MORNING AS WE GET A BETTER CO-LOCATION OF DEEPER MOISTURE TRANSPORT
COURTESY OF A DECENT LOW LEVEL JET...ANOTHER PACIFIC
DISTURBANCE...AND PWATS APPROACHING 2 INCHES. WE HANG ONTO SE FLOW
AT THE SURFACE FARTHER EAST...WHICH WOULD THEN GIVE THE HIGHER
CONCERN FOR MODERATE TO HEAVY PRECIP RATES SOUTH AND WEST. THERE
IS A SEVERE THREAT GIVEN THE MODEST WESTERLY FLOW NORTH OF THE
RIDGE...BUT DESTABILIZATION CONCERNS EXIST AT THIS POINT IN TIME
TO NAIL DOWN THE SPECIFICS YET.
KMD
&&
.LONG TERM...
303 PM CDT
MORNING LONG TERM DISCUSSION FORTHCOMING...PREVIOUS DISCUSSION
FOLLOWS.
FRIDAY NIGHT THROUGH THURSDAY...
THE GENERAL TREND FOR THE EXTENDED FORECAST PERIOD WILL BE FOR A
SLOWLY PROGRESSIVE UPPER LEVEL PATTERN THAT TRANSITIONS FROM A LOW
AMPLITUDE PATTERN TO ONE OF HIGH AMPLITUDE LONG WAVELENGTH. AT THE
BEGINNING OF THE EXTENDED PERIOD...BROAD RIDGING COVERS THE CNTRL
CONUS AND TROUGHING OVER THE WEST AND EAST COASTS.
FOR FRIDAY NIGHT THROUGH MONDAY NIGHT...THE MAIN CONCERNS WILL BE A
SERIES OF WEAK SHORTWAVES OVERTOPPING THE RIDGE. THESE SHORTWAVES
WILL BE THE MAIN FORCING FOR PERIODIC CHANCES FOR SHRA/TSRA. A DEEP
UPPER LOW CROSSING THE CANADIAN PRAIRIES WILL BEGIN TO SUPPRESS THE
RIDING OVER THE NRN PLAINS/GREAT LAKES REGIONS. THROUGH THE
WEEKEND...THE MAIN TRACK OF SHORTWAVE ENERGY WILL SHIFT TO THE SOUTH
WITH UPPER LEVEL FLOW GRADUALLY SHIFTING TO NWLY ALOFT AS THE UPPER
RIDGE BUILDS BACK OVER THE ROCKIES AND A LONG WAVE TROUGH DIGS OVER
THE EAST COAST. THE NEXT EFFECT OF THE PATTERN SHIFT IS TO RELOCATE
THE FOCUS OF PCPN POTENTIAL FROM THE UPPER MIDWEST AND GREAT LAKES
TO THE MIDDLE MISSISSIPPI AND OHIO VALLEYS. THE MOST LIKELY CHANCES
FOR PCPN ACROSS THE CWA WILL BE DURG THE PERIOD FROM LATE SATURDAY
NIGHT INTO EARLY MONDAY...THOUGH THERE MAY STILL BE A LINGERING
CHANCE FOR SOME SHRA/TSRA FRIDAY EVENING GENERALLY FOR THE NRN
PORTIONS OF THE CWA. WHILE THE LARGER SCALE MODELS HAVE A DECENT
HANDLE ON THE GENERAL PATTERN...TIMING DIFFERENCES FOR THE WEAK
SHORTWAVES INTRODUCE A FAIR AMOUNT OF UNCERTAINTY TO TIMING OF PCPN
IMPACTING THE REGION. BY MONDAY NIGHT AND THROUGH EARLY NEXT
WEEK...THE UPPER RIDGE WILL GRADUALLY BUILD EAST ACROSS THE CNTRL
PLAINS...SHIFTING THE NWLY FLOW AND SHORTWAVE TRACK TO THE
EAST...KEEPING THE REMAINDER OF THE EXTENDED PERIOD DRY.
THE TEMPERATURE TREND THROUGH THE EXTENDED PERIOD WILL BE FOR
GENERALLY BELOW NORMAL TEMPERATURES UNDER THE NWLY FLOW ALOFT. FOR
THE WEEKEND AND INTO EARLY NEXT WEEK...HIGHS SHOULD BE IN THE LOWER
80S...WITH LOWS IN THE 60S. BY EARLY NEXT WEEK...TEMPERATURES WILL
TREND A BIT LOW AS SFC HIGH PRESSURE BUILDS ACROSS THE REGION
SETTING UP FLOW OFF OF THE LAKE. FOR THE MIDDLE OF NEXT WEEK...HIGHS
SHOULD ONLY BE IN THE MIDDLE TO UPPER 70S WITH LOWS IN THE UPPER
50S.
KREIN
&&
.CLIMATE...
309 AM CDT
THURSDAY WAS THE 20TH CONSECUTIVE DAY WITH HIGH TEMPERATURES AT OR
ABOVE 80F OFFICIALLY FOR ROCKFORD AND CHICAGO. CURRENT FORECAST
WOULD SUGGEST AT LEAST ANOTHER 4 DAYS...POSSIBLY MORE TACKED ON TO
THE CURRENT STREAK DURING THE NEXT 7 DAYS. FOR ROCKFORD...IT IS
NOT ALL THAT UNCOMMON FOR LONG STRETCHES OF 80F+ WEATHER IN THE
SUMMER DUE TO THEIR GREATER DISTANCE FROM THE COOLING EFFECTS OF
LAKE MICHIGAN. IN FACT...ASSUMING THE CURRENT STREAK REACHES 24
DAYS IN ROCKFORD THAT WOULD JUST BARELY BREAK THE TOP 50 FOR
LONGEST STRETCHES OF 80F OR GREATER HIGHS. THE LONGEST STRETCH WAS
86 DAYS BACK IN 1895...THOUGH MORE RECENTLY IN 2012 THERE WAS A 56
DAY STRETCH OF HIGHS AT OR ABOVE 80 EVERY DAY.
FOR CHICAGO...THANKS TO THE COOLING EFFECTS OF LAKE MICHIGAN IT IS
MORE UNUSUAL TO SEE STREAKS OF GREATER THAN 3 WEEKS OF HIGHS 80 OR
ABOVE. ASSUMING THE CURRENT STREAK CONTINUES THROUGH SUNDAY AS
FORECAST THAT WOULD BRING THE TOTAL UP TO 24 DAYS STRAIGHT WHICH
WOULD PUT MAKE THIS STREAK ONE OF THE TOP 15 LONGEST ON RECORD.
HERE ARE THE TOP 15 LONGEST STREAKS OF DAYS WITH HIGHS 80F OR
ABOVE IN CHICAGO...
RANK # DAYS END DATE
1 46 8/16/2010 <--
2 44 8/ 8/2012 <--
3 42 8/ 7/1955
4 34 9/ 6/1995
5 32 8/ 8/1983
6 30 7/19/1921
7 29 8/18/1988
8 27 8/ 9/2011 <--
27 8/ 6/1999
27 7/14/1966
11 25 8/15/2007 <--
12 24 7/26/2005 <--
24 9/ 5/1983
24 8/25/1947
15 23 8/ 7/1987
23 7/ 9/1949
ASSUMING THE CURRENT STREAK REACHES AT LEAST 24 DAYS AS
FORECAST...THEN 6 OUT OF THE TOP 15 LONGEST STREAKS OF 80F OR
GREATER DAYS IN CHICAGO WILL HAVE OCCURRED SINCE 2005...4 OF THOSE
YEARS WILL HAVE BEEN SINCE 2010 ALONE!
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* LAKE BREEZE/SHIFT TO EAST/SOUTHEAST WINDS THIS AFTERNOON.
* POSSIBLE SCATTERED SHOWERS LATE IN THE FORECAST PERIOD.
RODRIGUEZ
//DISCUSSION...UPDATED 06Z...
VFR CONDITIONS IN PLACE EARLY THIS MORNING...WITH LIGHT WINDS AND
ONLY HIGH LEVEL CLOUD COVER IN PLACE. VFR CONDITIONS ARE EXPECTED
MOST OF THE FORECAST PERIOD...WHILE SOUTHERLY WINDS STEADILY
INCREASE LATER THIS MORNING. MONITORING SHOWERS/THUNDERSTORMS TO
THE NORTHWEST MOVING THROUGH PORTIONS OF IOWA AND
WISCONSIN...LIKELY CONTINUING EAST THIS MORNING.
HOWEVER...SOUTHERN EXTENT OF THIS PRECIP SHIELD WILL LIKELY ERODE
KEEPING DRY CONDITIONS ACROSS THE TERMINALS THROUGH MIDDAY. THIS
SYSTEM/FRONT WILL SHIFT EAST LATER TODAY WITH ADDITIONAL SHOWERS
AND THUNDERSTORMS LIKELY PUSHING TOWARDS THE TERMINALS IN THE
AFTERNOON...WITH RFD HAVING THE HIGHER CHANCES OF OBSERVING THIS
PRECIP. THE REMAINING TERMINALS WILL THEN HAVE THESE HIGHER
CHANCES BY THE EVENING. WITH SOME POTENTIAL FOR THIS PRECIP TO
STAY NORTH THIS EVENING...HAVE EXCLUDED ANY MENTION FOR THE OTHER
TERMINALS AT THIS TIME.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE FOR WINDS/LAKE BREEZE TODAY.
* LOW MEDIUM CONFIDENCE FOR SHOWERS.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
* SATURDAY...DRY/VFR. SOUTHEAST WINDS.
* SUNDAY...CHANCE OF SHRA/TSRA. SOUTHEAST WINDS.
* MONDAY...CHANCE OF SHRA/TSRA. NORTHEAST WINDS.
* TUESDAY AND WEDNESDAY...DRY/VFR. NORTH/NORTHEAST WINDS.
&&
.MARINE...
302 AM CDT
LIGHTER EASTERLY WINDS IN PLACE EARLY THIS MORNING WILL OBSERVE A
STEADY INCREASE TODAY WHILE SHIFTING TO MORE OF A SOUTHERLY
COMPONENT...AS LOW PRESSURE TO THE WEST OVER THE NORTHERN PLAINS
SLOWLY PUSHES EAST. STILL THINK A 10 TO 20 KT WIND WILL BE THE
HIGHEST TODAY...BUT SOME GUIDANCE IS HINTING AT POSSIBLE HIGHER
SPEEDS THROUGHOUT THE DAY. ALTHOUGH I DID INCREASE SPEEDS...DID
NOT GO AS HIGH. HOWEVER...DID MENTION A FEW GUSTS TO 25KT FOR THE
OPEN WATERS TODAY. IT DOES LOOK LIKE A BETTER WINDOW FOR STRONGER
WINDS OF 15 TO 25 KT ACROSS THE NORTH TONIGHT INTO SATURDAY
MORNING...AND HAVE TRENDED THAT WAY WITH THE FORECAST. THIS WILL
BE IN RESPONSE TO THE APPROACHING LOW...BUT WITH IT
WEAKENING...SPEEDS WILL DIMINISH SATURDAY INTO SATURDAY NIGHT.
EXACT TIMING AND PLACEMENT OF THE NEXT SYSTEM LATE IN THE WEEKEND
IS STILL UNCERTAIN BUT IT DOES APPEAR TO BE ANOTHER PERIOD WHEN
SPEEDS WILL ONCE AGAIN INCREASE...AT LEAST FOR THE SOUTHERN HALF
OF THE LAKE.
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:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION...CORRECTED
NWS NORTHERN INDIANA
412 PM EDT FRI AUG 7 2015
.SYNOPSIS...
ISSUED AT 410 PM EDT FRI AUG 7 2015
AN UPPER LEVEL DISTURBANCE TRACKING ACROSS THE GREAT LAKES TONIGHT
MAY BRING ISOLATED SHOWERS TO PORTIONS OF EXTREME NORTHERN INDIANA
AND SOUTHERN LOWER MICHIGAN THROUGH SATURDAY MORNING. MOST AREAS
WILL REMAIN DRY THROUGH SATURDAY...BUT CLOUDS WILL BE ON THE
INCREASE. LOW TEMPERATURES TONIGHT WILL RANGE FROM THE UPPER 50S TO
LOWER 60S. HIGH TEMPERATURES ON SATURDAY CAN BE EXPECTED TO REACH
BACK AROUND THE 80 DEGREE MARK.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 410 PM EDT FRI AUG 7 2015
A COMPACT UPPER LEVEL SHORT WAVE WILL CONTINUE EASTWARD ACROSS
THE WESTERN GREAT LAKES THIS EVENING...ALTHOUGH LATEST SHORT TERM
TRENDS SEEM TO SUGGEST THIS SHORT WAVE IS BECOMING INCREASINGLY
SHEARED. A LARGE AREA OF SHOWERS WITH A FEW EMBEDDED THUNDERSTORMS
IS ACCOMPANYING THIS VORT. SHORT TERM RAP TRENDS SUGGEST THIS WAVE
WILL BECOMING INCREASINGLY SHEARED WITH A MORE NARROWED CHANNEL OF
DPVA WORKING FROM WEST TO EAST ACROSS THE LOCAL AREA IN THE 22Z-
04Z TIMEFRAME. LOW LEVEL THETAE TROUGH CURRENTLY RESIDING ACROSS
THE AREA IS PROVIDING A FAIRLY SHARP WEST-EAST INSTABILITY
GRADIENT FROM THE MID MS VALLEY TO THE OHIO VALLEY...AND WOULD
EXPECT SOME DIMINISHING TREND IN COVERAGE AS THIS WAVE LOSES SOME
POTENCY AND DUE TO EFFECTS OF INITIALLY DRY AIR MASS ACROSS THE
REGION. HAVE MAINTAINED SOME SLIGHT CHANCE POPS PARTICULARLY
ACROSS THE FAR NORTHWEST/NORTH THIS EVENING FOLLOWING THIS
FORCING...WITH MORE QUESTIONABLE MOISTURE RETURN ACROSS REMAINDER
OF THE AREA ARGUING FOR MAINTENANCE OF DRY FORECAST.
FORCING WITH THIS WAVE WILL WANE LATE EVENING...BUT LAGGING LOW
LEVEL THETAE RIDGE MAY BEGIN TO HAVE SOME INFLUENCE OVERNIGHT INTO
EARLY SATURDAY MORNING. HAVE OPTED TO KEEP SOME SLIGHT CHANCE POPS
GOING OVERNIGHT INTO EARLY SATURDAY MORNING ACROSS THE
NORTH/NORTHWEST DUE TO LINGERING ADVECTIVE FORCING AND APPROACH OF A
VERY WEAK REMNANT SFC TROUGH. SOME EASTWARD PROGRESSION OF DAMPENED
LOW LEVEL THERMAL RIDGING ON SATURDAY SHOULD SOMEWHAT OFFSET
EXPECTED MORE CLOUD COVER ON SATURDAY FOR HIGHS ONCE AGAIN AROUND
80...OR POSSIBLY INTO THE LOWER 80S DEPENDING ON EXTENT OF CLOUD
COVER.
&&
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 410 PM EDT FRI AUG 7 2015
AN UPPER LEVEL SYSTEM OVER THE WESTERN CONUS WILL EJECT AN
UPPER LEVEL TROF OVER THE LARGE UPPER LEVEL SOUTHERN PLAINS RIDGE
AND THEN THE TROF WILL MOVE INTO THE UPPER GREAT LAKES REGION BY
EARLY SUNDAY. NCEP MODELS...THE CANADIAN GEM AND THE ECMWF WERE
SHOWING LARGE DIFFERENCES IN HANDLING THIS SYSTEM. FAVOR A
SOUTHERN TRACK WHICH IS SUPPORTED THE BY ECMWF AND THE CPS
ANALOGS. ALSO...MOST MODELS TRACKED THE SYSTEM EARLIER THIS WEEK
TOO FAR NORTH. SO FOR THIS PACKAGE...KEPT A CHANCE FOR STORMS
SUNDAY. HOWEVER...INCREASED STORM CHANCES A LITTLE OVER SOUTHWEST
AREAS IN DEFERENCE TO THE ECMWF. IF THE SOUTHERN TRACK
VERIFIES...CHANCES FOR SEVERE STORMS SHOULD BE LIMITED MORE TO THE
SOUTH AND SOUTHWEST. OTHERWISE...SOME LINGERING SHOWERS AND STORMS
ARE POSSIBLE MONDAY AND THEN CONDITIONS SHOULD BE DRY WITH
TEMPERATURES A LITTLE BELOW NORMAL AS A LARGE UPPER LEVEL TROF
REMAINS OVER THE AREA NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 410 PM EDT FRI AUG 7 2015
(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 555 AM EDT FRI AUG 7 2015
SOME WEAK LOW LEVEL WARM/MOIST ADVECTION WILL COMMENCE LATE THIS
EVENING/TONIGHT ACROSS NORTHWEST INDIANA/SOUTHWEST LOWER MICHIGAN.
A SMALL SCALE BUT FAIRLY STRONG VORT MAX TRACKING OUT OF CENTRAL
WISCONSIN COMBINED WITH ADVECTIVE FORCING MAY BE ENOUGH FOR A FEW
SHOWERS MOVING INTO PORTIONS OF NORTHWEST INDIANA THIS EVENING.
GREATER PROBABILITIES OF AN ISOLATED SHOWER WILL LIKELY REMAIN
NORTH OF KSBN SO WILL MAINTAIN A DRY FORECAST FOR SNOW. THE
INITIALLY DRY SUBCLOUD LAYER WILL ALLOW FOR MAINTENANCE OF VFR
CONDITIONS THROUGH THIS PERIOD...WITH ANY PATCHY SHALLOW FOG
FORMATION EARLY SATURDAY MORNING NOT LIKELY TO AFFECT TERMINALS.
EAST/SOUTHEAST WINDS TODAY WILL VEER SOUTHERLY FOR SATURDAY WITH
SPEEDS UNDER 10 KNOTS CONTINUING.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...SKIPPER
AVIATION...MARSILI
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS GOODLAND KS
335 PM MDT FRI AUG 7 2015
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 159 PM MDT FRI AUG 7 2015
BIGGEST CHALLENGE IN SHORT TERM IS THUNDERSTORM POTENTIAL THIS
AFTERNOON AND OVERNIGHT. NUMEROUS RUNS OF THE RAP PERSIST IN
BREAKING OUT SCATTERED AFTERNOON CONVECTION ACROSS THE CENTRAL
AND NORTHEAST COUNTIES...GENERALLY IN THE VICINITY OF A VERY WEAK
DECAYING SURFACE BOUNDARY. HAVE SOME DOUBTS ABOUT THIS LOOKING AT
CURRENT SATELLITE TRENDS AND SPC MESOANALYSIS CINH...BUT HAVE LEFT
THE SLIGHT CHANCE POPS NONETHELESS.
BIGGER ISSUE IS DEVELOPMENT OF STORMS OVER COLORADO LATER THIS
AFTERNOON AND THEIR SUBSEQUENT MOVEMENT. WATER VAPOR IMAGERY
SHOWS THE APPROACH OF THE NEXT UPSTREAM SHORTWAVE TROUGH AND RADAR
NOW SHOWS INITIAL THUNDERSTORM DEVELOPMENT SOUTH OF DENVER. MOST
GUIDANCE...INCLUDING THE CONVECTION-ALLOWING MODELS...INDICATES
BEST COVERAGE OF STORMS WILL BE ACROSS NORTHEAST COLORADO INTO
SOUTHWEST NEBRASKA...CLIPPING NORTHWEST KANSAS WITH LESSER
COVERAGE SOUTH AND EAST. ULTIMATELY IT DEPENDS ON UPSCALE
DEVELOPMENT AND WHETHER OR NOT A DECENT MCS CAN DEVELOP AND
PRODUCE STORMS FURTHER SOUTHEAST OF THE MAIN SHORTWAVE. HAVE
CONTINUED THE PREVIOUS FORECAST TREND OF BEST COVERAGE NORTH AND
NORTHWEST WITH LESSER POTENTIAL SOUTH OF I-70.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 334 PM MDT FRI AUG 7 2015
FORECAST PROBLEM WILL BE THUNDERSTORM CHANCES AND ANY HEAVY
RAINFALL THREAT. SATELLITE IS SHOWING AN AMPLIFIED AND MOSTLY
PROGRESSIVE FLOW FROM THE PACIFIC INTO NORTH AMERICA. THIS FLOW
BECOMES MORE OF A SPLIT WITH THE TROUGHS ALONG THE WEST AND EAST
COASTS. A LOT OF PACIFIC AND MONSOONAL MOISTURE IS BEING PULLED UP
INTO THE REGION. CURRENTLY A SYNOPTIC BOUNDARY REMAINS DRAPED TO
OUR SOUTH AND WEST.
AT JET LEVEL...MODELS STARTED OUT FINE. AT MID LEVELS...MODELS WERE
NOT TOO FAR APART. THE CANADIAN/UKMET/GFS LED THE PACK WITH OTHERS
NOT FAR BEHIND WITH THE SREF THE WORST. THE NAM/SREF WERE HANLDING
THE SURFACE WIND AND PRESSURE FIELD THE BEST. MODELS TENDED TO BE A
LITTLE COOL ON THE LOW LEVEL THERMAL FIELD WITH THE GFS/CANADIAN
DOING THE BEST.
SATURDAY NIGHT...TO BEGIN THE NIGHT...SURFACE BOUNDARY IS DRAPED
OVER THE FAR SOUTH AND WEST CENTRAL PORTION OF THE AREA. THIS
BOUNDARY GRADUALLY SINKS SOUTH THROUGH THE NIGHT. SHORTWAVE TROUGH
MOVES THROUGH FROM THE SOUTHWEST THROUGH THE NIGHT WITH THE BEST
LIFT BASICALLY OVER THE SOUTHWEST HALF. MAIN JET AXIS/LIFT STAYS NOT
TOO FAR TO OUR NORTH AND WEST THROUGH MOST OF THE PERIOD. LATE IN
THE NIGHT A RIGHT REAR QUADRANT GETS CLOSER TO THE NORTHWEST PORTION.
RIGHT NOW THE HIGHEST POPS LOOK TO BE IN THE SOUTHWEST HALF. PWS
REMAIN NEAR 1.5 INCHES. THAT WITH STORM MOTIONS ONLY 10 TO 15 KNOTS
ALONG THAT FLOW COMING OVER THE TOP OF THE SOUTHERN BOUNDARY WILL
MAKE MODERATE TO LOCALLY HEAVY RAINFALL POSSIBLE. ALSO POSSIBLE LATE
IN THE NIGHT WITH MOIST LOW LEVELS AND LITTLE TO NO WIND THAT PATCHY
FOG COULD DEVELOP WHERE NO PRECIPITATION IS GOING ON.
SUNDAY/SUNDAY NIGHT...IT LOOKS LIKE THERE MAY BE SOME LINGERING
RAINFALL AND PATCHY FOG IN THE MORNING. FOR THE REMAINDER OF THE
PERIOD...BOUNDARY LOOKS TO BE TO THE SOUTH AND WEST OF THE AREA WITH
A WEAK LOW LEVEL UPSLOPE REGIME IN PLACE. HOWEVER...MODELS ARE
HINTING AT A WEAK SECONDARY BOUNDARY MOVING INTO THE NORTHWEST HALF
OF THE AREA DURING THE LATE AFTERNOON INTO THE EVENING. THIS SINKS A
LITTLE FURTHER SOUTHEAST DURING THE LAST HALF OF THE NIGHT.
THE MID LEVEL FORCING THROUGH THE PERIOD REMAINS RATHER WEAK WITH
THE STRONGEST IN THE EVENING. RIGHT REAR QUADRANT OF THE JET REMAINS
NEAR THE NORTHERN AND WESTERN PORTIONS OF THE AREA THROUGH THE DAY
BUT GETS CLOSER/HAS MORE AFFECT ON THOSE LOCATIONS BY THE END OF THE
DAY. THE NORTHERN PORTION OF THE AREA KEEPS GETTING AFFECTED BY THIS
THROUGH THE MIDDLE OF THE NIGHT. WITH A VARIETY OF FORCING IN
DIFFERENT TIMES AND PLACES...WILL BROADBRUSH CHANCE POPS FOR THE
ENTIRE NIGHT.
FOR THE HIGH TEMPERATURES...WILL HAVE LOW LEVEL UPSLOPE IN PLACE
THROUGH THE DAY ALONG WITH LINGERING CLOUD COVER IN THE MORNING AND
DEVELOPING CLOUD COVER IN THE AFTERNOON WITH THE CONVECTION. MODEL
GUIDANCE HAS TENDED TO BE A LITTLE WARM.
MONDAY...JET REMAINS WELL NORTH OF THE AREA THROUGH THE DAY. MID
LEVEL SHORTWAVE RIDGE IS IN PLACE THROUGH THE DAY WITH A LOT OF
DRYING. A SHORTWAVE TROUGH STARTS GETTING CLOSER DURING THE END OF
THE DAY. AREA IS IN A POST FRONTAL AIR MASS. DEPENDING ON WHICH
MODEL YOU USE...THERE COULD BE A WEAK SUBTLE SURFACE BOUNDARY IN THE
FAR SOUTH/SOUTHWEST. SO AT THIS TIME...WILL HAVE SLIGHT TO LOW
CHANCE POPS IN THE FAR SOUTH AND SOUTHWEST PORTION OF THE AREA IN
THE AFTERNOON.
HIGH TEMPERATURES WILL BE COOLER THAN THE PREVIOUS DAY DUE TO LOWER
850 MB TEMPERATURES...UPSLOPE WINDS AND LINGERING MORNING FOG/STRATUS
THAT BEGINS SUNDAY NIGHT.
MONDAY NIGHT THROUGH SATURDAY...CONTINUED AMPLIFIED PATTERN
REMAINS IN PLACE THROUGH THE PERIOD. HOWEVER...THE DETERMINISTIC
AND ENSEMBLE OUTPUT SPREAD GETS WORSE WITH TIME...ALMOST
COMPLETELY OUT OF PHASE AT TIMES. THE DIFFERENCES INVOLVE HOW THE
PERSISTENT SOUTHERN UNITED STATES RIDGE AND WEST TROUGH EVOLVE
WITH TIME. IN GENERAL THE ECMWF REMAINS STRONGER WITH THE RIDGE.
FOR THE WESTERN TROUGH...ALL OUTPUT SUPPORTS A DEEPENING ALONG THE
COAST UPPER TROUGH.
DESPITE THOSE DIFFERENCES...THE CENTER OF THE RIDGE...STILL RATHER
FAR SOUTH...AND THE POSITION OF THE UPPER TROUGH SHOULD CONTINUE TO
ALLOW PACIFIC AND MONSOONAL MOISTURE TO PULLED UP INTO THE REGION
WITH PERIODIC SHORTWAVE TROUGHS EMBEDDED WITHIN THIS FLOW. AT THE
SURFACE...WPC GRAPHICS SHOW A PERSISTENT FRONTAL BOUNDARY STILL
DRAPED NOT TOO FAR TO OUR SOUTH AND WEST OR OVER THE AREA. THIS
KEEPS A CONTINUED UPSLOPE FLOW OVER THE AREA.
GIVEN THE BIG MODEL DIFFERENCES...THE GENERAL PATTERN SUPPORTED
CONTINUED BOUTS OF MOISTURE/LIFT/RAINFALL...AND THE PROXIMITY OF A
BOUNDARY AND UPSLOPE FLOW...SHOULD SEE A CONTINUED THREAT FOR
THUNDERSTORMS AND DO NOT FEEL COMFORTABLE MAKING ANY MAJOR
ADJUSTMENTS TO THE GUIDANCE. THE DETAILS WILL HAVE TO BE REFINED AS
WE GET CLOSER TO EACH EVENT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1139 AM MDT FRI AUG 7 2015
VFR WITH STRENGTHENING SOUTHEAST WINDS THIS AFTERNOON AT BOTH
TERMINALS. A FEW SCATTERED STORMS WILL BE POSSIBLE NEAR KMCK BY
MID-AFTERNOON...BUT A WEATHER SYSTEM ALOFT MOVING UP FROM THE
SOUTHWEST WILL HELP INITIATE THE MAIN ROUND OF THUNDERSTORMS THIS
EVENING...GENERALLY IN THE 01Z-06Z TIME FRAME. HEAVY RAINFALL...LARGE
HAIL AND STRONG WINDS WILL ACCOMPANY STRONGER STORMS. POTENTIAL
ONCE AGAIN FOR FOG/STRATUS AT KMCK TOWARD SUNRISE.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DLF
LONG TERM...BULLER
AVIATION...DLF
AREA FORECAST DISCUSSION
NWS GOODLAND KS
200 PM MDT FRI AUG 7 2015
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 159 PM MDT FRI AUG 7 2015
BIGGEST CHALLENGE IN SHORT TERM IS THUNDERSTORM POTENTIAL THIS
AFTERNOON AND OVERNIGHT. NUMEROUS RUNS OF THE RAP PERSIST IN
BREAKING OUT SCATTERED AFTERNOON CONVECTION ACROSS THE CENTRAL
AND NORTHEAST COUNTIES...GENERALLY IN THE VICINITY OF A VERY WEAK
DECAYING SURFACE BOUNDARY. HAVE SOME DOUBTS ABOUT THIS LOOKING AT
CURRENT SATELLITE TRENDS AND SPC MESOANALYSIS CINH...BUT HAVE LEFT
THE SLIGHT CHANCE POPS NONETHELESS.
BIGGER ISSUE IS DEVELOPMENT OF STORMS OVER COLORADO LATER THIS
AFTERNOON AND THEIR SUBSEQUENT MOVEMENT. WATER VAPOR IMAGERY
SHOWS THE APPROACH OF THE NEXT UPSTREAM SHORTWAVE TROUGH AND RADAR
NOW SHOWS INITIAL THUNDERSTORM DEVELOPMENT SOUTH OF DENVER. MOST
GUIDANCE...INCLUDING THE CONVECTION-ALLOWING MODELS...INDICATES
BEST COVERAGE OF STORMS WILL BE ACROSS NORTHEAST COLORADO INTO
SOUTHWEST NEBRASKA...CLIPPING NORTHWEST KANSAS WITH LESSER
COVERAGE SOUTH AND EAST. ULTIMATELY IT DEPENDS ON UPSCALE
DEVELOPMENT AND WHETHER OR NOT A DECENT MCS CAN DEVELOP AND
PRODUCE STORMS FURTHER SOUTHEAST OF THE MAIN SHORTWAVE. HAVE
CONTINUED THE PREVIOUS FORECAST TREND OF BEST COVERAGE NORTH AND
NORTHWEST WITH LESSER POTENTIAL SOUTH OF I-70.
.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 235 AM MDT FRI AUG 7 2015
AN UPPER LEVEL RIDGE WILL BE IN PLACE OVER THE TRI STATE AREA TO
START OFF THE LONG TERM PERIOD MONDAY. THE CENTRAL AREA OF HIGH
PRESSURE WILL CONTINUE TO RETROGRADE AND INCREASE IN AMPLITUDE OVER
THE ROCKY MOUNTAIN RANGE AND THE NORTHERN PLAINS TUESDAY. WITH THE
PRESENCE OF THE UPPER RIDGE...JET AREAS AND POCKETS OF VORTICITY
WILL REMAIN WELL AWAY FROM THE TRI STATE AREA...WHICH WILL BRING
UPPER STABILITY FOR THE REST OF THE FORECAST PERIOD.
AT THE SURFACE...A COLD FRONT WILL MOVE THROUGH THE FORECAST AREA
MONDAY AND BRING COOLER THAN NORMAL TEMPERATURES IN THE MIDDLE 80S.
THE FRONT WILL STALL OUT SOMEWHERE ALONG THE SOUTHERN EDGES OF THE
FORECAST AREA...SO CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE
GREATEST THERE MONDAY AFTERNOON AND EVENING WITH SURFACE CONVERGENCE
AND SOME INSTABILITY ALOFT. MODEL SOUNDINGS SHOW PLENTY OF MOIST
AIR WITH PRECIPITABLE WATER VALUES BETWEEN 1 AND 1.5...SO ANY
DEVELOPING STORMS COULD BRING SOME HEAVY DOWNPOURS AT TIMES.
SURFACE SOUTHERLY FLOW AND WARM AIR ADVECTION RETURNS TUESDAY
THROUGH THE REST OF THE PERIOD AS THE FORMER SURFACE COLD FRONT
DISSOLVES. ALTHOUGH THE UPPER LEVEL HIGH WILL BE POSITIONED RIGHT
OVER THE FORECAST AREA...A SURFACE TROUGH IN EASTERN COLORADO IN
COMBINATION WITH THE PRESENCE OF A DRY LINE IN THE AFTERNOON HOURS
COULD BRING SOME CHANCES FOR THUNDERSTORM DEVELOPMENT. MODEL
SOUNDINGS SHOW THAT SURFACE HEATING MAY NOT BE ENOUGH TO BREAK CAP
IN PLACE...BUT ANY FORCING PROVIDED IN AREAS OF UPSLOPE FLOW OR
ALONG THE DRY LINE MAY PRODUCE SOME STRONGER THUNDERSTORMS. NOT
THINKING SEVERE STORMS WILL BE WIDESPREAD DUE TO THE LACK OF JET OR
BULK SHEAR VALUES IN PLACE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1139 AM MDT FRI AUG 7 2015
VFR WITH STRENGTHENING SOUTHEAST WINDS THIS AFTERNOON AT BOTH
TERMINALS. A FEW SCATTERED STORMS WILL BE POSSIBLE NEAR KMCK BY
MID-AFTERNOON...BUT A WEATHER SYSTEM ALOFT MOVING UP FROM THE
SOUTHWEST WILL HELP INITIATE THE MAIN ROUND OF THUNDERSTORMS THIS
EVENING...GENERALLY IN THE 01Z-06Z TIME FRAME. HEAVY RAINFALL...LARGE
HAIL AND STRONG WINDS WILL ACCOMPANY STRONGER STORMS. POTENTIAL
ONCE AGAIN FOR FOG/STRATUS AT KMCK TOWARD SUNRISE.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DLF
LONG TERM...MK
AVIATION...DLF
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1009 PM CDT SAT AUG 8 2015
.UPDATE...TEMPERATURES HAVE FALLEN INTO THE 80S AREA WIDE THIS
EVENING, HOWEVER TEMPS ARE EXPECTED TO QUICKLY RISE AGAIN BEFORE
NOON SUNDAY. AWAY FROM THE IMMEDIATE COAST HIGH TEMPS ARE EXPECTED
TO RUN IN THE MID 90S LOW 100S WITH HEAT INDEX VALUES VERY CLOSE
TO, REACHING, OR SURPASSING THE ADV CRITERIA OF 108, THEREFORE A
HEAT ADV HAS BEEN ISSUED FOR THE ENTIRE AREA FROM 11 AM THROUGH
7PM SUNDAY.
ASIDE FROM THE TEMPS THE WX IS EXPECTED TO REMAIN QUIET AND NO
OTHER CHANGES WERE NEEDED THIS EVENING.
TINGLER
&&
.PREV DISCUSSION... /ISSUED 637 PM CDT SAT AUG 8 2015/
DISCUSSION...
FOR THE 09/00Z TAF ISSUANCE.
AVIATION...
A COUPLE OF STORMS HAVE DEVELOPED OVER EXTREME NORTHEAST LOUISIANA
AND WESTERN MISSISSIPPI...MOVING TO THE SOUTH AND SOUTHWEST.
LATEST HRRR DOES TAKE THE ACTIVITY TO THE DOOR STEP OF KAEX AROUND
09/01-02Z. AT THIS POINT...ACTIVITY SHOULD WEAKEN OR DISSIPATE
BEFORE REACHING KAEX. SO WILL NOT MENTION IN TAF.
OTHERWISE...PERSISTENCE LOOKS LIKE THE WAY TO GO. SOUTH WINDS
AROUND 10 KNOTS AND SCATTERED CU WITH THE PASSING SEA BREEZE WILL
DIMINISH AFTER SUNSET...WITH MAINLY VFR FOR THE REMAINDER OF THE
EVENING. ALTHOUGH WILL NOT PLACE IN THE TAF...SLIGHT CHANCE THAT
SOME MVFR CONDITIONS MAY BRIEFLY OCCUR AT SITES DURING THE
OVERNIGHT AND BEFORE SUNRISE FROM PATCHY FOG/HAZE LOW STRATUS.
THEN MAINLY A REPEAT ON SUNDAY...WITH VFR CONDITIONS AND SOUTH
WINDS AROUND 10 KNOTS WITH SCATTERED CU DEVELOPING ALONG THE SEA
BREEZE AFTER 09/20Z.
RUA
PREV DISCUSSION... /ISSUED 423 PM CDT SAT AUG 8 2015/
UPDATE...THE HEAT ADV HAS BEEN EXPANDED TO COVER THE REST OF THE
CWA THROUGH 0Z. HEAT INDEX VALUES HAVE TOUCHED 110 AT KLCH AND 111
AT KUXL WITH MANY OTHER SITES RANGING AROUND OR CLOSE TO 108
OUTSIDE THE PREVIOUS ADV AND GENERALLY 10 MILES AWAY FROM THE
COAST. CAMERON IS THE ONLY ZONE WHERE TEMPS WERE NOT CLOSE TO
108, HOWEVER THE ONLY RELIABLE OBS ARE AT THE SOMEWHAT COOLER
COAST.
WILL LOOK AT TOMORROW AFTERNOON SOON AND LIKELY ISSUE AN ADV FOR
SUN AFTERNOON AT OR BY THE EXPIRATION TIME OF THE CURRENT ADV.
TINGLER
PREV DISCUSSION... /ISSUED 318 PM CDT SAT AUG 8 2015/
SYNOPSIS...DYNAMIC HIGH PRESSURE WILL REMAIN ANCHORED OVER EAST
TEXAS AND LOUISIANA INTO MONDAY. SUBSIDENCE EACH DAY SHOULD HAVE A
POSITIVE FEEDBACK EFFECT WITH INCREASING MAX TEMPS SUNDAY AND
MONDAY.
SHORT TERM...WENT JUST BELOW GUIDANCE ON MIN TEMPS TNITE WITH
LACK OF CLOUD COVER AND DRY CONDITIONS WITH SOUTHWESTERLY FLOW.
CONVECTIVE INHIBITION SHOULD DOMINATE THRU MONDAY, SHOULD CONTINUE
DRY. A HEAT ADVISORY WILL LIKELY BE NEEDED FOR SUNDAY OVER
PORTIONS OF THE AREA.
LONG TERM...EXCESSIVE HEAT ON MONDAY WILL LIKELY REQUIRE AN
AREA-WIDE HEAT ADVISORY. RELIEF WILL COME AS A STRONG TROF THRU
THE GREAT LAKES BRINGS AN APPROACHING COOL FRONT ON WEDNESDAY.
THIS COULD TRIGGER A FEW SHOWERS AND THUNDERSTORMS INTO THURSDAY
AS THERE SHOULD BE SUFFICIENT MOISTURE OUT AHEAD OF THIS SYSTEM.
THERE IS GOOD AGREEMENT ON THIS FRONT BETWEEN THE GFS AND THE
EURO.
CLIMATE...LOOKS LIKE RECORD HIGH TEMPERATURES WILL BE APPROACHED
ON MONDAY AUG 11TH.
LOCATION RECORD YEAR
ALEXANDRIA 105 1907;
LAKE CHARLES 101 2007;
BEAUMONT 102 1962;
LAFAYETTE 101 2007;
NEW IBERIA 102 2007.
SWEENEY
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 77 101 78 103 / 10 0 10 10
LCH 79 98 78 99 / 0 0 10 10
LFT 80 99 79 100 / 0 10 10 10
BPT 76 99 77 100 / 0 0 10 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...HEAT ADVISORY FROM 11 AM TO 7 PM CDT SUNDAY FOR LAZ027>033-
041>045-052>055-073-074.
TX...HEAT ADVISORY FROM 11 AM TO 7 PM CDT SUNDAY FOR TXZ180-201-215-
216-259>262.
GM...NONE.
&&
$$
PUBLIC...05
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
637 PM CDT SAT AUG 8 2015
.DISCUSSION...
FOR THE 09/00Z TAF ISSUANCE.
&&
.AVIATION...
A COUPLE OF STORMS HAVE DEVELOPED OVER EXTREME NORTHEAST LOUISIANA
AND WESTERN MISSISSIPPI...MOVING TO THE SOUTH AND SOUTHWEST.
LATEST HRRR DOES TAKE THE ACTIVITY TO THE DOOR STEP OF KAEX AROUND
09/01-02Z. AT THIS POINT...ACTIVITY SHOULD WEAKEN OR DISSIPATE
BEFORE REACHING KAEX. SO WILL NOT MENTION IN TAF.
OTHERWISE...PERSISTENCE LOOKS LIKE THE WAY TO GO. SOUTH WINDS
AROUND 10 KNOTS AND SCATTERED CU WITH THE PASSING SEA BREEZE WILL
DIMINISH AFTER SUNSET...WITH MAINLY VFR FOR THE REMAINDER OF THE
EVENING. ALTHOUGH WILL NOT PLACE IN THE TAF...SLIGHT CHANCE THAT
SOME MVFR CONDITIONS MAY BRIEFLY OCCUR AT SITES DURING THE
OVERNIGHT AND BEFORE SUNRISE FROM PATCHY FOG/HAZE LOW STRATUS.
THEN MAINLY A REPEAT ON SUNDAY...WITH VFR CONDITIONS AND SOUTH
WINDS AROUND 10 KNOTS WITH SCATTERED CU DEVELOPING ALONG THE SEA
BREEZE AFTER 09/20Z.
RUA
&&
.PREV DISCUSSION... /ISSUED 423 PM CDT SAT AUG 8 2015/
UPDATE...THE HEAT ADV HAS BEEN EXPANDED TO COVER THE REST OF THE
CWA THROUGH 0Z. HEAT INDEX VALUES HAVE TOUCHED 110 AT KLCH AND 111
AT KUXL WITH MANY OTHER SITES RANGING AROUND OR CLOSE TO 108
OUTSIDE THE PREVIOUS ADV AND GENERALLY 10 MILES AWAY FROM THE
COAST. CAMERON IS THE ONLY ZONE WHERE TEMPS WERE NOT CLOSE TO
108, HOWEVER THE ONLY RELIABLE OBS ARE AT THE SOMEWHAT COOLER
COAST.
WILL LOOK AT TOMORROW AFTERNOON SOON AND LIKELY ISSUE AN ADV FOR
SUN AFTERNOON AT OR BY THE EXPIRATION TIME OF THE CURRENT ADV.
TINGLER
PREV DISCUSSION... /ISSUED 318 PM CDT SAT AUG 8 2015/
SYNOPSIS...DYNAMIC HIGH PRESSURE WILL REMAIN ANCHORED OVER EAST
TEXAS AND LOUISIANA INTO MONDAY. SUBSIDENCE EACH DAY SHOULD HAVE A
POSITIVE FEEDBACK EFFECT WITH INCREASING MAX TEMPS SUNDAY AND
MONDAY.
SHORT TERM...WENT JUST BELOW GUIDANCE ON MIN TEMPS TNITE WITH
LACK OF CLOUD COVER AND DRY CONDITIONS WITH SOUTHWESTERLY FLOW.
CONVECTIVE INHIBITION SHOULD DOMINATE THRU MONDAY, SHOULD CONTINUE
DRY. A HEAT ADVISORY WILL LIKELY BE NEEDED FOR SUNDAY OVER
PORTIONS OF THE AREA.
LONG TERM...EXCESSIVE HEAT ON MONDAY WILL LIKELY REQUIRE AN
AREA-WIDE HEAT ADVISORY. RELIEF WILL COME AS A STRONG TROF THRU
THE GREAT LAKES BRINGS AN APPROACHING COOL FRONT ON WEDNESDAY.
THIS COULD TRIGGER A FEW SHOWERS AND THUNDERSTORMS INTO THURSDAY
AS THERE SHOULD BE SUFFICIENT MOISTURE OUT AHEAD OF THIS SYSTEM.
THERE IS GOOD AGREEMENT ON THIS FRONT BETWEEN THE GFS AND THE
EURO.
CLIMATE...LOOKS LIKE RECORD HIGH TEMPERATURES WILL BE APPROACHED
ON MONDAY AUG 11TH.
LOCATION RECORD YEAR
ALEXANDRIA 105 1907;
LAKE CHARLES 101 2007;
BEAUMONT 102 1962;
LAFAYETTE 101 2007;
NEW IBERIA 102 2007.
SWEENEY
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 75 100 78 103 / 10 0 10 10
LCH 77 98 78 99 / 0 0 10 10
LFT 76 100 79 100 / 0 10 10 10
BPT 77 100 77 100 / 0 0 10 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR LAZ027>033-041>045-
052>055-073-074.
TX...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR TXZ180-201-215-216-
259>262.
GM...NONE.
&&
$$
AVIATION...07
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
756 PM EDT SAT AUG 8 2015
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 250 PM EDT SAT AUG 8 2015
THE UPPER GREAT LAKES REGION WILL BE BETWEEN UPPER LEVEL FEATURES
OVER THE NEXT 24 HOURS...LEADING TO SOME UNCERTAINTY IN THE COVERAGE
AND AMOUNT OF PRECIPITATION THAT WILL OCCUR AHEAD OF THE COLD FRONT
TONIGHT. THE MAIN SHORTWAVE IS CURRENTLY LOCATED JUST TO THE EAST OF
LAKE WINNIPEG AND HAS A 1002MB SURFACE LOW LOCATED WITH IT. A COLD
FRONT STRETCHES SOUTH-SOUTHEAST FROM THIS LOW AND INTO NORTHERN
MINNESOTA (CURRENTLY FROM THE LAKE OF THE WOODS TO JUST TO THE EAST
OF FARGO). HAVE SEEN SOME SHOWERS AND THUNDERSTORMS DEVELOP AROUND
PARK RAPIDS MINNESOTA A COUPLE HOURS AGO AND THEY HAVE BEEN MAKING
THERE WAY TO THE EAST TOWARDS LEECH LAKE AHEAD OF THAT FRONT AND IN
THE RIBBON OF DEEPER MOISTURE FROM 925-700MB AHEAD OF THE ASSOCIATED
TROUGH. OVER THE U.P....THE ABUNDANT DRY AIR SEEN ABOVE 700MB ON THE
12Z KGRB SOUNDING AND ON RAP ANALYSIS DATA...ASSOCIATED WITH THE
SURFACE RIDGE FROM A HIGH NEAR JAMES BAY...HAS BEEN LIMITING THE
EASTWARD EXTENT OF THE OF SHOWERS AS THEY MOVE INTO WESTERN LAKE
SUPERIOR. BUT WITH THE MOISTURE BELOW 700MB...HAVE SEEN DIURNAL CU
FILL IN THE GAPS FROM EARLIER TODAY BETWEEN THE SOUTHEASTERLY FLOW
UPSLOPE FOG AND LOW CLOUDS. TEMPERATURES HAVE WARMED INTO THE 70S
ACROSS THE AREA...WITH THE WARMEST VALUES OVER THE EAST WITH MORE
SUNSHINE. FINALLY FARTHER TO THE SOUTH...A SHORTWAVE ROUNDING THE
UPPER RIDGE OVER TEXAS/OKLAHOMA LED TO AN MCS MOVING THROUGH
NORTHEAST KANSAS AND SOUTHWEST MISSOURI EARLY THIS MORNING AND IT
HAS SINCE DISSIPATED. BUT WITH ANOTHER WAVE ROUNDING THE RIDGE
THROUGH NEBRASKA...WOULD EXPECT REDEVELOPMENT TO THE EAST OF THAT
AREA OVER THE NEXT COUPLE OF HOURS.
WITH THE SOUTHERN SHORTWAVE STAYING WELL TO THE SOUTH OF THE
AREA...THE MAIN FOCUS WILL BE WITH THE UPPER LOW NEAR LAKE WINNIPEG
SLOWLY WEAKENING AS IT MOVES EAST TOWARDS JAMES BAY. THIS WILL LEAD
TO THE SURFACE LOW FOLLOWING SUIT AND SLOWLY DRAGGING THE COLD FRONT
EAST ACROSS THE CWA. HAVE ALREADY SEEN SHOWERS/THUNDERSTORMS DEVELOP
IN NORTHERN MINNESOTA AHEAD OF THE FRONT AND WITH THE STORM MOTION
VALUES INDICATING EASTWARD MOVEMENT UP TO 30KTS...WOULD EXPECT THE
SHOWERS TO SPREAD EAST INTO WESTERN LAKE SUPERIOR AND EVENTUALLY THE
WESTERN U.P. TONIGHT. LIKE LAST NIGHT AND TODAY...THEY WILL BE
BATTLING THE EXISTING DRY MID LEVEL AIR AS THEY MOVE OUT AHEAD OF
THE SLOW MOVING SURFACE-850MB TROUGH...SO WOULD EXPECT SOME
DIMINISHMENT AS THEY HEAD TO THE EAST AND INTO THE CWA TONIGHT.
WOULD EXPECT SOME MARGINALLY SEVERE STORMS TO MOVE INTO WESTERN LAKE
SUPERIOR BEFORE THE DRY AIR AND LOSS OF DIURNAL HEATING STARTS TO
TAKE ITS TOLL. OVER THE CENTRAL AND EASTERN U.P....AM EXPECTED SOME
PATCHY GROUND FOG TO DEVELOP TONIGHT. THICKNESS WILL DEPEND ON THE
AMOUNT OF DECOUPLING THAT OCCURS TONIGHT. HAVE SHOWN THE THICKEST
FOG (AREAS COVERAGE) OVER THE CENTRAL U.P. FOR SOUTHERN
MARQUETTE...DICKINSON...DELTA...AND NORTHERN MENOMINEE COUNTIES.
WITH THE COLD FRONT STILL OFF TO THE WEST OF THE U.P. ON SUNDAY
MORNING...EXPECT THERE TO BE TIME FOR DIURNAL HEATING TO INCREASE
THE POTENTIAL FOR SHOWERS/THUNDERSTORMS OVER THE WEST/CENTRAL U.P.
DURING THE AFTERNOON. MODELS HAVE A VARIETY OF IDEAS ON ML CAPE
VALUES...RANGING FROM 250-2000 J/KG TOMORROW AFTERNOON JUST AHEAD OF
THE FRONT. LOOKING AT MODIFIED SOUNDINGS AND MEAN ML CAPE VALUES
FROM THE NCAR ENSEMBLES AND SREF...FEEL THAT VALUES AROUND 500-750
J/KG ARE A FAIRLY REASONABLE EXPECTATION AT THIS POINT. WITH 0-6KM
BULK SHEAR VALUES GENERALLY AROUND 25-30KTS...THERE IS THE POTENTIAL
FOR AN ISOLATED STRONGER STORM TOMORROW AFTERNOON. THAT MATCHES THE
IDEA FROM UPDRAFT VELOCITY/HELICITY FROM THE CAM/S AND CAM
ENSEMBLES. WITH WET BULB ZERO VALUES NEARING 10KFT AND FREEZING
LEVEL ABOVE 12KFT...THINK THAT WILL COMBINE WITH THE MARGINAL SHEAR
TO KEEP THE HAIL THREAT BORDERLINE. LIKED THE PREVIOUS SHIFTS
HANDLING OF THE DEVELOPMENT OF THE SHOWERS/THUNDERSTORMS ACROSS THE
CENTRAL U.P. (RAMPING UP TO LOCALIZED LIKELY VALUES OVER MARQUETTE
COUNTY) AND HAVE ONLY MADE MINOR ADJUSTMENTS BASED OFF LATEST MODEL
TRENDS.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 315 PM EDT SAT AUG 8 2015
AFTER ANY LINGERING SHOWERS END ON MON FOLLOWING A SUN NGT COLD
FROPA...THE NW FLOW BTWN A BLDG UPR RDG IN THE PLAINS AND AN
AMPLIFYING TROF OVER ERN NAMERICA WL BE THE DOMINATING INFLUENCE ON
UPR MI WX EARLY IN THE WEEK. THE RESULT WL BE A RETURN OF DRY AND
COOLER WX FOR THE MOST PART MON INTO WED. THE NEXT CHC OF SHOWERS/TS
WL ARRIVE WITH WARMER AIR WED NGT THRU THU NGT AHEAD OF A SHRTWV
MOVING OVER THE TOP OF THE RDG/THRU NW ONTARIO AND ITS ATTENDANT
COLD FNT. HI PRES TRAILING THIS COLD FNT SHOULD BRING A SEASONABLE
AIRMASS/DRIER WX LATE IN THE WEEK.
SUN NGT...SHRTWV DRIFTING ESEWD THRU FAR NORTHERN ONTARIO WL REACH
NEAR JAMES BAY BY 12Z MON AND DRAG ATTENDANT COLD FNT SLOWLY THRU
THE UPR LKS. SINCE THE SHARPER DYNAMIC FORCING ASSOCIATED WITH THE
ONTARIO SHRTWV WL BE REMAIN TO THE N AND H85 THETA E ADVECTION/
DEEPER MSTR INFLOW WL BE WEAK AT BEST...EXPECT NO MORE THAN A CHC OF
SHOWERS/TS. THE BEST CHC FOR THIS PCPN WL BE IN THE EVNG OVER
CENTRAL UPR MI...WHERE AXIS OF SOMEWHAT HIER H85 THETA E WL BE
PRESENT AT TIME WHEN DAYTIME HEATING WL STILL BE A FACTOR. THE
MAJORITY OF THE MODELS SHOW A TRAILING SHRTWV/AREA OF HIER MID LVL
MSTR/SOME DPVA AND H7-3 QVECTOR CNVGC APRCHG FM CENTRAL MN FOLLOWING
THE COLD FROPA. HOWEVER...NOCTURNAL COOLING AND LLVL DRYING/
NEGATIVE H85 THETA E ADVCTN WL LIMIT THE COVERAGE/INTENSITY OF ANY
SHOWERS THAT MIGHT ACCOMPANYING THIS HIER LVL FORCING. EXPECT THE
LOWEST MIN TEMPS OVER THE W...WHERE H85 TEMPS ARE FCST TO FALL TO
ARND 11C BY DAYBREAK.
MON...EXPECT ANY LINGERING SHOWERS OVER THE E AND SCENTRAL TO
DIMINISH WITH ARRIVAL OF DEEP DRYING/INCRSG LLVL ACYC NNW FLOW AHEAD
OF CNDN HI PRES BLDG INTO MANITOBA. LINGERING MID CLDS WL GIVE WAY
TO SOME DIURNAL CU/SC IN THE AFTN. EXPECT HI TEMPS MAINLY IN THE 70S
TO NEAR 80 OVER THE SCNTRL WITH H85 TEMPS IN THE 12-14C RANGE.
LOCATIONS NEAR LK SUP WL BE COOLEST WITH A NW FLOW OFF THE WATER.
MON NGT THRU TUE NGT...ARRIVAL OF MORE VIGOROUS DEEP LYR QVECTOR
DVGC/SUBSIDENCE UNDER CONFLUENT NW FLOW ALOFT BTWN PLAINS RDG/ERN
TROF AND H85 TEMPS FALLING AS LO AS 8 TO 10C IN THE LLVL NLY FLOW
AHEAD OF CNDN HI PRES BLDG TOWARD THE UPR LKS WL RESULT IN A PERIOD
OF COOLER AND DRIER WX FOR THE CWA. SOME OF THE MODELS HAVE BEEN
GENERATING SOME LGT PCPN MAINLY DURING DAYTIME HEATING ON TUE
ACCOMPANYING THE PASSAGE OF A SHRTWV IN THE NW FLOW. BUT ABSENCE OF
ANY MSTR INFLOW...LARGER SCALE NEGATIVE DYNAMIC FORCING/SUBSIDENCE
THAT WL MAINTAIN MID LVL CAPPING SHOWN ON THE GFS FCST SDNGS AS WELL
AS DIFFLUENT LLVL FLOW WARRANTS MAINTAINING GOING DRY FCST FOR NOW.
BUT THERE WL BE A GOOD DEAL OF DIURNAL CU ON TUE UNDER INCOMING H85
THERMAL TROF. EXPECT LO TEMPS ON TUE NGT TO FALL INTO THE 40S AT THE
COOLER INTERIOR LOCATIONS WITH MOCLR SKIES/LIGHT WINDS AS THE SFC HI
PRES MOVES OVHD.
WED...AS THE HI CENTER DRIFTS TO THE S...THE LLVL FLOW WL TURN TO
THE WSW. THE WARMING RELATED TO SOME WAA AND CONTINUED SUBSIDENCE
UNDER THE SLOWLY EXPANDING PLAINS RDG/RISING HGTS IS FCST TO BOOST
H85 TEMPS TO ARND 16C OVER THE W LATE IN THE DAY. EXPECT A WARMER
DAY THAN ON TUE...WITH HI TEMPS AT LEAST APRCHG 80 ESPECIALLY OVER
THE W AWAY FM LK MODERATION...EVEN IF SOME WAA CLDS SPILL OVER THE
CWA IN THE AFTN.
WED NGT THRU THU NGT...ALTHOUGH THERE ARE SOME DIFFERENCES IN THE
DETAILS AS EXPECTED SO FAR INTO THE FUTURE...THE LONGER RANGE
GUIDANCE INDICATES A SHRTWV RIDING OVER THE PLAINS RDG WL DROP SEWD
THRU NW ONTARIO ON THU/THU NGT AND DRAG A COLD FNT THRU THE UPR LKS
ON THU NGT. SOME OF THE MODELS GENERATE SOME LGT PCPN AS EARLY AS
WED NGT IN THE WSW FLOW/WAA BTWN THE RETREATING HI PRES TO THE S AND
FALLING MSLP OVER SCENTRAL CANADA AHEAD OF THE SHRTWV. BUT LINGERING
LLVL ACYC FLOW AND RELATIVE DRYNESS OF AIRMASS INDICATE ANY SHOWERS
WL BE WIDELY SCT AT BEST. A BETTER CHC FOR SHOWERS/TS APPEARS WL
COME LATE THU/THU EVNG WITH THE ARRIVAL OF SOME DEEP LYR QVECTOR
CNVGC ASSOCIATED WITH THE ONTARIO SHRTWV AND AHEAD OF APRCHG COLD
FNT DURING PERIOD OF DAYTIME HEATING. THE 12Z GFS IS MOST VIGOROUS
WITH THIS DISTURBANCE AND INDICATES THE POTENTIAL FOR SOME SVR
STORMS WITH MUCAPE FCST AS HI AS 2500 J/KG AND DEEP LYR SHEAR UP TO
40 KTS. THE 12Z ECMWF/CNDN MODELS SHOW A LESS IMPRESSIVE SCENARIO
WITH WEAKER MSTR RETURN. GIVEN MODEL DIFFERENCES AND UNCERTAINTY ON
THE DEGREE OF MSTR RETURN WITH SHARPEST FORCING REMAINING TO THE
NE...CONSENSUS LO CHC POPS AT THIS POINT SEEM REASONABLE. THU LOOKS
TO BE THE WARMEST DAY OF THE WEEK UNDER THERMAL RDG/H85 TEMPS UP TO
18-20C AHEAD OF INCOMING COLD FNT.
FRI/SAT...HI PRES TRAILING THE SHRTWV SHOULD BRING DRY AND SOMEWHAT
COOLER WX AT LEAST ON FRI/FRI NGT. THERE IS SOME UNCERTAINTY ON HOW
QUICKLY WAA SHOWERS/TS RETURN BTWN THE RETREATING HI AND ANOTHER
SHRTWV RIDING OVER THE PLAINS RDG LATER ON SAT.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 755 PM EDT SAT AUG 8 2015
THUNDERSTORMS OVER MN ASSOCIATED WITH THE COLD FRONT WILL DIMINISH
AS THEY MOVE EAST THIS EVENING. COULD NOT RULE OUT A SHOWER AT IWD
OR EVEN CMX OVERNIGHT...BUT THIS SEEMS UNLIKELY AS THE AIRMASS IS
FAIRLY DRY ACROSS THE AREA. MAIN CONCERN FOR TONIGHT WILL BE
POSSIBLE FOG AND LOW CLOUDS AT SAW OVERNIGHT. SOME GUIDANCE SUGGESTS
LIFR CONDITIONS DEVELOPING AT SAW OVERNIGHT INTO EARLY SUN MORNING.
HOWEVER...WITH THE HIGH CLOUDS IN PLACE ACROSS THE AREA DO NOT FEEL
LIKE THERE WILL BE THE BEST OPPORTUNITY FOR LIFR CONDITIONS. IF
ANYTHING...EXPECT MVFR FOG TO DEVELOP LATER TONIGHT.
OTHERWISE...THE COLD FRONT WILL PASS ACROSS UPPER MICHIGAN ON
SUNDAY. EXPECT SHOWERS AND THUNDERSTORMS TO DEVELOP ALONG THE FRONT
IN CENTRAL UPPER MICHIGAN SUN AFTN. THESE COULD CERTAINLY IMPACT
SAW...BUT TIMING AND COVERAGE IS STILL UNCERTAIN SO AS SUCH WILL
KEEP ANY MENTION OF THUNDER OUT OF THE TERMINAL FOR NOW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 250 PM EDT SAT AUG 8 2015
A LOW MOVING FROM JUST EAST OF LAKE WINNIPEG TO JAMES BAY THIS
WEEKEND WILL SWEEP A SURFACE TROUGH ACROSS LAKE SUPERIOR ON
SUNDAY...LEADING TO A SHIFT IN THE WINDS FROM A LIGHT SOUTH TO
SOUTHEASTERLY DIRECTION TO THE NORTHWEST BY MONDAY. WITH A
GENERALLY LIGHT PRESSURE GRADIENT IN PLACE...EXPECT WINDS TO STAY
BELOW 20KTS THROUGH THE PERIOD...ESPECIALLY AFTER TUESDAY WHEN HIGH
PRESSURE WILL SETTLE OVER THE GREAT LAKES REGION FOR THE MIDDLE OF
NEXT WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...KC
AVIATION...MRD
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
315 PM EDT FRI AUG 7 2015
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 254 PM EDT FRI AUG 7 2015
A SHORTWAVE HAS UNDERCUT THE UPPER RIDGE OVER THE UPPER MISSISSIPPI
VALLEY AND IS NOW DIVING SOUTHEAST ACROSS EASTERN WISCONSIN. THAT
WAVE IS SUPPORTING THE SHOWERS AND A FEW EMBEDDED THUNDERSTORMS
MOVING ACROSS THAT AREA. FARTHER TO THE WEST...A 1008MB SURFACE LOW
IS LOCATED NEAR EAU CLAIRE WISCONSIN. TO THE NORTHEAST OF THE
SURFACE LOW...AN AREA OF SHOWERS ARE MOVING EAST ACROSS UPPER
MICHIGAN AT THIS TIME...TIED TO THE NORTHERN EDGE OF THE 850-700MB Q-
VECTOR CONVERGENCE AND BROAD WARM AIR ADVECTION. THE HEAVIEST RAIN
SO FAR TODAY HAS FALLEN OVER THE WESTERN HALF OF THE U.P....WITH 0.5
TO 0.65 INCHES OF RAIN FALLING OVER THE BARAGA PLAINS TODAY. AMOUNTS
DIMINISH TO A TENTH OF AN INCH THROUGH 2PM FROM NEGAUNEE SOUTH TO
IRON MOUNTAIN AND EVEN LESS FARTHER TO THE EAST.
THE SURFACE LOW AND SHORTWAVE WILL SLOWLY DISSIPATE AS THEY MOVE TO
THE EAST-SOUTHEAST TONIGHT...LIMITING THE INFLUENCE OF BOTH FEATURES
THROUGH THE NIGHT. EXPECT THE SHOWERS TO DIMINISH AND DRIFT TO THE
SOUTHEAST THROUGH THE EVENING (TIED TO THE 850-700MB Q-VECTOR
CONVERGENCE)...AND LARGELY BE OUT OF THE CWA AROUND 06Z. BUT WITH
THE MODELS CONTINUING TO SHOW LOW LEVEL MOISTURE PIVOTING TO THE
NORTHWEST ON THE NORTHEAST SIDE OF THE 925-850 TROUGH IN
CENTRAL/NORTHERN WISCONSIN...EXPECT ABUNDANT LOW CLOUDS TO BE IN
PLACE ACROSS THE AREA. THESE LOW CLOUDS CAN ALREADY BE SEEN OVER
EASTERN MINNESOTA AND WESTERN WISCONSIN...AND THEY HAVE BEEN WORKING
INTO WESTERN UPPER MICHIGAN THROUGH THE DAY. THINK DRYING AND
INCREASING SUBSIDENCE ABOVE THAT...GENERALLY ABOVE 750MB OVER THE
WEST...WILL ALSO HELP THE DIMINISHMENT OF THE WIDESPREAD SHOWERS.
DID HOLD ONTO THE SHOWERS A LITTLE LONGER OVER THE HIGHER TERRAIN
UPSLOPE AREAS IN CENTRAL UPPER MICHIGAN DUE TO THE FAVORABLY
SOUTHEASTERLY FLOW...BUT THE PRECIPITATION MAY FALL MORE AS DRIZZLE
THAN RAIN. IN ADDITION...HAVE TRENDED FOG UP TO AREAS TO WIDESPREAD
VALUES OVER THE WEST/CENTRAL U.P. WHERE THE BETTER RAIN HAS FALLEN
AND TIED TO THE LOWEST 5KFT BEING SATURATED ON THE NAM/GFS
SOUNDINGS. ONE ITEM TO WATCH...THE LATEST RAP RUNS HAVE BEEN HOLDING
ONTO DRIER NEAR SURFACE AIR OVER THE NORTH CENTRAL...WHICH WOULD
GREATLY REDUCE THE POTENTIAL FOR LOW CLOUDS AND FOG.
EXPECT THE LOW LEVEL MOISTURE TO HOLD ON THROUGH THE FIRST HALF OF
SATURDAY OVER THE WESTERN HALF TO TWO-THIRDS OF THE U.P. BEFORE THE
CONTINUED SUBSIDENCE AND INFLUX OF DRIER AIR TRIES TO BREAK OF THE
CLOUDS. WHILE THAT SHOULD RAISE THE CEILINGS ACROSS THE AREA...STILL
EXPECT THE WESTERN CWA TO REMAIN MOSTLY CLOUDY...WHILE THE EASTERN
THIRD OF THE U.P. WILL EXPERIENCE LINGERING MID CLOUDS IN THE
MORNING...TRANSITIONING TO DIURNAL CU IN THE AFTERNOON.
CONTINUED TO SHOW SLIGHT CHANCE POPS MOVING INTO WESTERN LAKE
SUPERIOR AND FAR WESTERN UPPER MICHIGAN TOMORROW AFTERNOON...AHEAD
OF THE SURFACE TROUGH MOVING INTO NORTHERN MINNESOTA AND THE
NORTHERN EDGE OF A SHORTWAVE MOVING THROUGH SOUTHERN MINNESOTA AND
NORTHERN IOWA. THINK MOST OF THE PRECIPITATION WILL STAY OFF TO THE
WEST FOR TOMORROW.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 314 PM EDT FRI AUG 7 2015
FCST FOCUS IN THE MEDIUM RANGE PERIOD WL BE ON POPS THE SECOND HALF
OF THIS WEEKEND ASSOCIATED WITH STRONG DISTUBANCE OVER SCENTRAL
CANADA THAT WL BE DROPPING SLOWLY ESEWD THRU NW ONTARIO AND DRAGGING
A COLD FNT ACRS UPR MI ON SUN NGT. TEMPS AHEAD OF THE COLD FROPA WL
BE AOA NORMAL. DURING THE FIRST HALF OF THE NEXT WEEK...EXPECT TEMPS
TO FALL BLO NORMAL WITH NW FLOW ALOFT DEVELOPING BTWN A BLDG UPR RDG
IN THE PLAINS AND DEEPENING TROF DOWNSTREAM IN ERN NAMERICA. CNDN HI
PRES UNDER THIS NW FLOW ALOFT WL BRING GENERALLY DRY WX DURING THE
MON THRU WED PERIOD. LOOKS LIKE TEMPS WL REBOUND AOA NORMAL LATER IN
THE WEEK AS PLAINS RDG BLDS TOWARD THE WRN LKS.
SAT NGT THRU SUN NGT...STRONG SHRTWV OVER FAR NW ONTARIO THAT WL BE
TOPPING UPR RDG IN THE PLAINS IS FCST TO SLIDE SLOWLY ESE THRU NRN
ONTARIO. ALTHOUGH THERE ARE STILL SOME TIMING DIFFERENCES...MOST OF
THE LATEST GUIDANCE INDICATE A FASTER PRIMARY COLD FROPA ON SUN NGT.
SINCE THE SHARPER DYNAMIC FORCING ASSOCIATED WITH THE ONTARIO SHRTWV
WL REMAIN TO THE N OF UPR MI...POPS/PCPN AMOUNTS AS EARLY AS SAT NGT
IN ADVANCE OF THIS COLD FNT WL DEPEND ON THE DEGREE TO WHICH MSTR
INFLOW INTO THE UPR LKS WL BE DISRUPTED BY A W-E ORIENTED BNDRY
STRETCHING FM IOWA INTO THE LOWER LKS AND CONVECTION THAT FIRES
ALONG THIS AXIS ACCOMPANYING THE PASSAGE OF ANOTHER SHRTWV OVER THAT
AREA. THE 12Z NAM IS MOST EXTREME SHOWING A NEAR ABSENCE OF PCPN
ACRS THE CWA DURING THIS ENTIRE PERIOD WITH A LACK OF ANY MSTR
INFLOW/DYNAMIC FORCING TO THE N OF STRONG TS COMPLEX/DEEPER SFC LO
TRACKING ALONG THE BNDRY. THE OTHER MODELS SHOW A MORE PRONOUNCED
AXIS OF HIER H85 THETA E AND THUS MORE DEEP LYR MSTR CNVGC/FORCING/
QPF. BEST CHC FOR SOMWHAT HIER POPS WL BE OVER THE W ON SAT EVNG AND
THEN THE CENTRAL ON SUN AFTN/EVNG...WHEN THE 12Z GFS SHOWS MUCAPE AS
HI AS 2500 J/KG...DURING PERIODS OF DAYTIME HEATING. BUT GIVEN
MODEL/TIMING UNCERTAINTIES AND SUPPORT FOR LARGER SCALE FORCING TO
PASS TO THE N AND S OF THE CWA...FCST WL POPS WL BE NO HIER THAN THE
CHC CATEGORY.
MON...SINCE RECENT MEDIUM RANGE GUIDANCE HAS TRENDED TO SPEED UP
PASSAGE OF COLD FROPA ATTENDANT TO SHRTWV SHIFTING ESEWD THRU NW
ONTARIO AND ARRIVAL OF DEEP LYR QVECTOR DVGC/LARGER SCALE
SUBSIDENCE/MID LVL DRYING...PCPN CHCS FOR MON LOOK TO BE
DIMINISHING. WITH MORE SUNSHINE...H85 TEMPS FCST IN IN THE 10 TO 12C
RANGE WL SUPPORT MAX TEMPS IN THE 70S. LOCATIONS NEAR LK SUP WL BE
COOLEST WITH LLVL NNW FLOW IN ADVANCE OF APRCHG CNDN HI PRES.
MON NGT THRU WED...THE UPR RDG IN THE PLAINS IS FCST TO AMPLIFY
EARLY IN THE WEEK...ALLOWING THE TROF IN ERN NAMERICA TO DEEPEN AND
A MORE PRONOUNCED NW FLOW ALOFT BTWN THESE FEATURES TO PREVAIL OVER
THE GREAT LKS. THE ARRIVAL OF CNDN HI PRES/H85 TEMPS AS LO AS 8 TO
10C WL RESULT IN GENERALLY DRY AND COOLER WX FOR MON NGT INTO WED.
ALTHOUGH SOME OF THE MODELS INDICATE A SHRTWV EMBEDDED IN THE NW
FLOW ALOFT COULD CAUSE SOME SHOWERS DURING DAYTIME HEATING ON TUE...
THE COVERAGE/INTENSITY OF THESE SHOWERS WL BE LIMITED BY THE ABSENCE
OF ANY DEEPER MSTR AND GENERAL LARGER SCALE SUBSIDENCE UNDER THE
CONFLUENT NW FLOW ALOFT. RETAINED GOING DRY FCST FOR NOW. WITH
PLENTY OF SUNSHINE...WED AFTN WL TURN WARMER AS H85 TEMPS REBOUND
TOWARD 15C OVER THE W AS THE PLAINS RDG SHIFTS TOWARD THE WRN LKS.
LATE WEEK...A NUMBER OF THE EXTENDED MODELS SHOW ANOTHER SHRTWV
ROUNDING THE TOP OF THE PLAINS RDG WL INFLUENCE THE AREA ON THU AND
BRING THE THREAT OF SOME SHOWERS/TS. AS THE UPR RDG TO THE W BUILDS
BACK TOWARD THE UPR LKS IN THE WAKE OF THIS SHRTWV PASSAGE...FRI
SHOULD BE DRY AND WARMER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 147 PM EDT FRI AUG 7 2015
A LOW CENTERED IN WISCONSIN IS SHIFTING RAIN SHOWERS EAST ACROSS
WESTERN UPPER MICHIGAN AND EXPECT THAT TO CONTINUE THROUGH THE
AFTERNOON. THIS WILL USHER IN INCREASING LOW LEVEL MOISTURE AND THE
BIGGEST QUESTION IS THE TIMING OF THE LOW CLOUDS ARRIVING AT
KCMX/KSAW. WITH THE HEAVIEST PRECIPITATION DIVING FARTHER TO THE
SOUTH...WONDERING IF THE LOW LEVEL MOISTENING WILL TAKE A LITTLE
LONGER THAN INITIALLY EXPECTED AND HAVE DELAYED THE ARRIVAL
SLIGHTLY. ONCE THE LOW CLOUDS ARRIVE...WOULD EXPECT IFR OR LOWER
CONDITIONS TO PREVAIL FOR MUCH OF THE REST OF THE PERIOD. DID
CONTINUE THE LOWER VISIBILITIES DUE TO FOG...ESPECIALLY FOR KSAW
WHERE THE FAVORABLE UPSLOPE SOUTHEASTERLY FLOW WILL BE IN PLACE.
DRIER AIR SHOULD GRADUALLY MOVE INTO THE AREA DURING THE DAY ON
SATURDAY AND BRINGING INCREASING CEILINGS AND VISIBILITIES.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 254 PM EDT FRI AUG 7 2015
A LOW PRESSURE SYSTEM OVER WESTERN WISCONSIN WILL DISSIPATE TONIGHT
INTO SATURDAY MORNING AS IT MOVES EAST. MEANWHILE...A STRONGER LOW
NEAR LAKE WINNIPEG WILL MOVE TO JAMES BAY BY MONDAY..SWEEPING A
BROAD TROUGH ACROSS THE UPPER GREAT LAKES REGION. HIGH PRESSURE
WILL BUILD IN BEHIND THE TROUGH...AND CONTINUE INTO THE MIDDLE OF
NEXT WEEK. WITH WEAK PRESSURE GRADIENTS EXPECTED...WINDS ARE
EXPECTED TO STAY BELOW 20KTS THROUGH THE PERIOD. FINALLY...WITH
RAIN AND ABUNDANT LOW LEVEL MOISTURE MOVING OVER WESTERN AND
CENTRAL LAKE SUPERIOR...COULD SEE SOME PATCHY FOG OVER THOSE AREAS
TONIGHT INTO SATURDAY MORNING...BUT DON/T EXPECT WIDESPREAD...DENSE
FOG AT THIS TIME.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...KC
AVIATION...SRF
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
254 PM EDT FRI AUG 7 2015
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 254 PM EDT FRI AUG 7 2015
A SHORTWAVE HAS UNDERCUT THE UPPER RIDGE OVER THE UPPER MISSISSIPPI
VALLEY AND IS NOW DIVING SOUTHEAST ACROSS EASTERN WISCONSIN. THAT
WAVE IS SUPPORTING THE SHOWERS AND A FEW EMBEDDED THUNDERSTORMS
MOVING ACROSS THAT AREA. FARTHER TO THE WEST...A 1008MB SURFACE LOW
IS LOCATED NEAR EAU CLAIRE WISCONSIN. TO THE NORTHEAST OF THE
SURFACE LOW...AN AREA OF SHOWERS ARE MOVING EAST ACROSS UPPER
MICHIGAN AT THIS TIME...TIED TO THE NORTHERN EDGE OF THE 850-700MB Q-
VECTOR CONVERGENCE AND BROAD WARM AIR ADVECTION. THE HEAVIEST RAIN
SO FAR TODAY HAS FALLEN OVER THE WESTERN HALF OF THE U.P....WITH 0.5
TO 0.65 INCHES OF RAIN FALLING OVER THE BARAGA PLAINS TODAY. AMOUNTS
DIMINISH TO A TENTH OF AN INCH THROUGH 2PM FROM NEGAUNEE SOUTH TO
IRON MOUNTAIN AND EVEN LESS FARTHER TO THE EAST.
THE SURFACE LOW AND SHORTWAVE WILL SLOWLY DISSIPATE AS THEY MOVE TO
THE EAST-SOUTHEAST TONIGHT...LIMITING THE INFLUENCE OF BOTH FEATURES
THROUGH THE NIGHT. EXPECT THE SHOWERS TO DIMINISH AND DRIFT TO THE
SOUTHEAST THROUGH THE EVENING (TIED TO THE 850-700MB Q-VECTOR
CONVERGENCE)...AND LARGELY BE OUT OF THE CWA AROUND 06Z. BUT WITH
THE MODELS CONTINUING TO SHOW LOW LEVEL MOISTURE PIVOTING TO THE
NORTHWEST ON THE NORTHEAST SIDE OF THE 925-850 TROUGH IN
CENTRAL/NORTHERN WISCONSIN...EXPECT ABUNDANT LOW CLOUDS TO BE IN
PLACE ACROSS THE AREA. THESE LOW CLOUDS CAN ALREADY BE SEEN OVER
EASTERN MINNESOTA AND WESTERN WISCONSIN...AND THEY HAVE BEEN WORKING
INTO WESTERN UPPER MICHIGAN THROUGH THE DAY. THINK DRYING AND
INCREASING SUBSIDENCE ABOVE THAT...GENERALLY ABOVE 750MB OVER THE
WEST...WILL ALSO HELP THE DIMINISHMENT OF THE WIDESPREAD SHOWERS.
DID HOLD ONTO THE SHOWERS A LITTLE LONGER OVER THE HIGHER TERRAIN
UPSLOPE AREAS IN CENTRAL UPPER MICHIGAN DUE TO THE FAVORABLY
SOUTHEASTERLY FLOW...BUT THE PRECIPITATION MAY FALL MORE AS DRIZZLE
THAN RAIN. IN ADDITION...HAVE TRENDED FOG UP TO AREAS TO WIDESPREAD
VALUES OVER THE WEST/CENTRAL U.P. WHERE THE BETTER RAIN HAS FALLEN
AND TIED TO THE LOWEST 5KFT BEING SATURATED ON THE NAM/GFS
SOUNDINGS. ONE ITEM TO WATCH...THE LATEST RAP RUNS HAVE BEEN HOLDING
ONTO DRIER NEAR SURFACE AIR OVER THE NORTH CENTRAL...WHICH WOULD
GREATLY REDUCE THE POTENTIAL FOR LOW CLOUDS AND FOG.
EXPECT THE LOW LEVEL MOISTURE TO HOLD ON THROUGH THE FIRST HALF OF
SATURDAY OVER THE WESTERN HALF TO TWO-THIRDS OF THE U.P. BEFORE THE
CONTINUED SUBSIDENCE AND INFLUX OF DRIER AIR TRIES TO BREAK OF THE
CLOUDS. WHILE THAT SHOULD RAISE THE CEILINGS ACROSS THE AREA...STILL
EXPECT THE WESTERN CWA TO REMAIN MOSTLY CLOUDY...WHILE THE EASTERN
THIRD OF THE U.P. WILL EXPERIENCE LINGERING MID CLOUDS IN THE
MORNING...TRANSITIONING TO DIURNAL CU IN THE AFTERNOON.
CONTINUED TO SHOW SLIGHT CHANCE POPS MOVING INTO WESTERN LAKE
SUPERIOR AND FAR WESTERN UPPER MICHIGAN TOMORROW AFTERNOON...AHEAD
OF THE SURFACE TROUGH MOVING INTO NORTHERN MINNESOTA AND THE
NORTHERN EDGE OF A SHORTWAVE MOVING THROUGH SOUTHERN MINNESOTA AND
NORTHERN IOWA. THINK MOST OF THE PRECIPITATION WILL STAY OFF TO THE
WEST FOR TOMORROW.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 504 AM EDT FRI AUG 7 2015
DURING THE LONG TERM...ZONALLY ORIENTED FLOW WILL PREVAIL THRU THE
UPPER GREAT LAKES INITIALLY...JUST S OF A TROF/RIDGE/TROF PATTERN
ACROSS SRN CANADA. UNDER THIS FLOW...MID LEVEL LOW CURRENTLY OVER
SRN SASKATCHEWAN IS FCST TO SLOWLY MOVE E INTO NRN ONTARIO BY SUN
MORNING. IN ITS WAKE...A FAIRLY AMPLIFIED RIDGE WILL DEVELOP TO THE
LEE OF THE ROCKIES EARLY NEXT WEEK AND THEN DRIFT SLIGHTLY E TO
CNTRL NAMERICA MIDWEEK. THIS WILL FORCE INCREASED TROFFING INTO ERN
NAMERICA DURING THE FIRST HALF OF NEXT WEEK...RESULTING IN
PRONOUNCED NNW FLOW DEVELOPING INTO THE UPPER GREAT LAKES. THESE
CHANGES WILL LEAD TO OPPORTUNITIES FOR PCPN OVER THE NEXT FEW DAYS
UNTIL NNW FLOW SHARPENS EARLY NEXT WEEK. HOPEFULLY...AREAS THAT NEED
A GOOD SOAKING RAIN WILL RECEIVE MUCH NEEDED RAINFALL IN THE NEXT
FEW DAYS. THE SHARP NNW FLOW DEVELOPING EARLY NEXT WEEK WITH SFC
HIGH PRES PREVAILING WILL BRING A RETURN TO DRY WEATHER.
HOWEVER...TYPICAL FOR SUMMERTIME NW FLOW...ANY SUBTLE SHORTWAVE
DROPPING THRU THE AREA COULD SPARK ISOLD AFTN CONVECTION. AS FOR
TEMPS...READINGS WON`T BE TOO FAR FROM NORMAL THRU THE WEEKEND (ON
THE WARM SIDE OF NORMAL FOR MOST LOCATIONS). NW FLOW DEVELOPING
EARLY NEXT WEEK WILL DROP TEMPS TO BLO NORMAL...BUT NOT
SIGNIFICANTLY AS THERE WON`T BE A TAP OF CHILLY AIR FROM NORTHERN
CANADA.
BEGINNING SAT...COMPLEX OF SHORTWAVE ENERGY RESPONSIBLE FOR SHRA
TODAY/TONIGHT WILL BE SHIFTING E OF THE AREA BY MORNING. AFTER ANY
LINGERING SHRA END...WEAK HEIGHT RISES/DEEP LAYER QVECTOR DIVERGENCE
SUGGEST DRY WEATHER WILL FOLLOW. MID LEVEL LOW CURRENTLY OVER SRN
SASKATCHEWAN WILL REACH THE MANITOBA/ONTARIO BORDER BY 00Z SUN.
WHILE ASSOCIATED COLD FRONT WILL STILL BE WELL W OF HERE IN NW MN
LATE IN THE AFTN...A NUMBER OF MODELS GENERATE SOME PCPN FARTHER E
INTO WRN UPPER MI WHERE MLCAPES INCREASE UPWARDS OF 500J/KG OR SO IN
THE PRESENCE OF THE ARRIVAL OF WEAK DEEP LAYER QVECTOR CONVERGENCE.
WILL KEEP FLAVOR OF INHERITED FCST AND MAINTAIN SCHC POPS IN THE
LATE AFTN OVER THE W.
SAT NIGHT THRU SUN NIGHT...MID LEVEL LOW DRIFTS ACROSS NRN ONTARIO.
TO THE S OF THIS FEATURE...MODELS INDICATE A TRAIN OF WEAK SHORTWAVE
ENERGY TRACKING E FROM THE NRN ROCKIES TO THE UPPER GREAT LAKES.
LACK OF A COHERENT FEATURE MAKES FOR LOW CONFIDENCE IN FORECASTING
COVERAGE OF SHRA/TSTMS AND TIMING OF BEST CHANCE OF PCPN. GIVEN THE
INHERENT UNCERTAINTY IN HOW CONVECTION WILL DEVELOP WITH THE STREAM
OF WEAK SHORTWAVE ENERGY...PLAN TO UTILIZE A CONSENSUS OF CURRENT
AND RECENT MODEL RUNS TO CONSTRUCT POPS. ALSO...IT APPEARS AT THIS
POINT THAT THERE PROBABLY WON`T BE SUFFICIENT INSTABILITY DEVELOPING
TO SUPPORT AN ORGANIZED SVR TSTM RISK...ESPECIALLY WITH DEEP LAYER
SHEAR UNDER 30KT THRU THE PERIOD. LATEST SPC OUTLOOKS CONCUR WITH
ONLY A GENERAL THUNDER OUTLOOK FOR UPPER MI.
BY THE TIME MON ROLLS AROUND...AFOREMENTIONED NNW FLOW WILL BE
LOCKING IN WITH COLD FRONT LIKELY E OF THE FCST AREA BY 12Z...
LEADING TO A DRYING TREND. DRY WEATHER SHOULD THEN BE THE RULE
TUE/WED AS SFC HIGH PRES ASSOCIATED WITH SHARP UPSTREAM RIDGE
ARRIVES. HOWEVER...ANY SUBTLE SHORTWAVE DROPPING THRU THE AREA COULD
SPARK ISOLD AFTN CONVECTION...ESPECIALLY TUE...BEFORE SFC HIGH PRES
SETTLES INTO THE AREA. RIGHT NOW...POTENTIAL IS NOT GREAT ENOUGH TO
INCLUDE AN EXPLICIT MENTION OF PCPN.
HEADING INTO THU...FCST WILL DEPEND ON WHETHER THE UPSTREAM RIDGE IS
PROGRESSIVE...BEGINS TO BREAK DOWN OR WHETHER ANY SHORTWAVES RIDE
AROUND THE RIDGE AND DROP TOWARD THE AREA. RECENT MEDIUM RANGE MODEL
RUNS HINT THAT THE RIDGE AXIS WILL REMAIN TO THE W AND SHORTWAVE
ENERGY WILL ROUND IT...PERHAPS BRINGING SHRA/TSRA CHC LATE IN THE
DAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 147 PM EDT FRI AUG 7 2015
A LOW CENTERED IN WISCONSIN IS SHIFTING RAIN SHOWERS EAST ACROSS
WESTERN UPPER MICHIGAN AND EXPECT THAT TO CONTINUE THROUGH THE
AFTERNOON. THIS WILL USHER IN INCREASING LOW LEVEL MOISTURE AND THE
BIGGEST QUESTION IS THE TIMING OF THE LOW CLOUDS ARRIVING AT
KCMX/KSAW. WITH THE HEAVIEST PRECIPITATION DIVING FARTHER TO THE
SOUTH...WONDERING IF THE LOW LEVEL MOISTENING WILL TAKE A LITTLE
LONGER THAN INITIALLY EXPECTED AND HAVE DELAYED THE ARRIVAL
SLIGHTLY. ONCE THE LOW CLOUDS ARRIVE...WOULD EXPECT IFR OR LOWER
CONDITIONS TO PREVAIL FOR MUCH OF THE REST OF THE PERIOD. DID
CONTINUE THE LOWER VISIBILITIES DUE TO FOG...ESPECIALLY FOR KSAW
WHERE THE FAVORABLE UPSLOPE SOUTHEASTERLY FLOW WILL BE IN PLACE.
DRIER AIR SHOULD GRADUALLY MOVE INTO THE AREA DURING THE DAY ON
SATURDAY AND BRINGING INCREASING CEILINGS AND VISIBILITIES.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 254 PM EDT FRI AUG 7 2015
A LOW PRESSURE SYSTEM OVER WESTERN WISCONSIN WILL DISSIPATE TONIGHT
INTO SATURDAY MORNING AS IT MOVES EAST. MEANWHILE...A STRONGER LOW
NEAR LAKE WINNIPEG WILL MOVE TO JAMES BAY BY MONDAY..SWEEPING A
BROAD TROUGH ACROSS THE UPPER GREAT LAKES REGION. HIGH PRESSURE
WILL BUILD IN BEHIND THE TROUGH...AND CONTINUE INTO THE MIDDLE OF
NEXT WEEK. WITH WEAK PRESSURE GRADIENTS EXPECTED...WINDS ARE
EXPECTED TO STAY BELOW 20KTS THROUGH THE PERIOD. FINALLY...WITH
RAIN AND ABUNDANT LOW LEVEL MOISTURE MOVING OVER WESTERN AND
CENTRAL LAKE SUPERIOR...COULD SEE SOME PATCHY FOG OVER THOSE AREAS
TONIGHT INTO SATURDAY MORNING...BUT DON/T EXPECT WIDESPREAD...DENSE
FOG AT THIS TIME.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...ROLFSON
AVIATION...SRF
MARINE...SRF
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
247 PM EDT FRI AUG 7 2015
.SHORT TERM...TONIGHT
ORGANIZING DEFORMATION ASSOCIATED WITH THE LOW AMPLITUDE WAVE
APPROACHING THE WESTERN SHORES OF LAKE MICHIGAN AT PRESS TIME IS
SUPPORTING AN ORGANIZING RAIN SHIELD OVER EASTERN WISCONSIN. MODEL
PROGS REMAIN INSISTENT THAT THIS WAVE WILL BECOME INCREASINGLY
SHEARED THIS EVENING, THE EARLY SIGNS OF WHICH ARE ALREADY BECOMING
EVIDENT ON CURRENT WV IMAGERY. CEILINGS WITHIN THE ACTIVE AREA OF
PRECIP ARE GENERALLY ABOVE 7KFT, A TESTAMENT TO THE AMOUNT OF DRY
AIR IN THE COLUMN. PER 12Z DTX SOUNDING AND LATEST RAP PROGS, EVEN
DRIER AIR RESIDES OVER SOUTHEAST MICHIGAN. TAKEN IN CONSIDERATION
WITH RAPIDLY WEAKENING FORCING OVER THE NEXT SEVERAL HOURS, THIS
CASTS DOUBT ON THE ABILITY OF PRECIP TO SURVIVE ITS TREK INTO
SOUTHEAST MICHIGAN. SOME SEMBLENCE OF THE MID-LEVEL CIRCULATION MAY
PROVIDE JUST ENOUGH ASCENT/DEFORMATION TO RESULT IN A PERIOD OF
LIGHT RAIN FALLING OUT OF HIGH CLOUDS OVER THE SAGINAW VALLEY WHERE
A HIGH CHC POP IS IN PLACE. ELSEWHERE...JUST A CHC LATE TONIGHT
NORTH OF I-69 WITH NO WX MENTION ELSEWHERE. GUIDANCE LOOKS ON TRACK
WITH LOWS IN THE LOW TO MID 60S...A FEW DEGREES WARMER THAN LAST
NIGHT OWING TO INCREASED CLOUD COVER.
&&
.LONG TERM...SATURDAY THROUGH THURSDAY
DAMPENING MID LEVEL WAVE AND ATTENDANT 100 KNOT UPPER JET CORE IN
THE PROCESS OF PIVOTING THROUGH LOWER MICHIGAN EARLY SATURDAY. MOST
FAVORABLE UPPER LEVEL FORCING TIED TO THESE FEATURES WILL TEND TO
ALIGN FROM THE TRI-CITIES/THUMB INTO NORTHERN LOWER MICHIGAN THROUGH
THIS TIME. THIS WILL MAINTAIN A WINDOW FOR LIGHT SHOWER PRODUCTION
ACROSS THIS CORRIDOR DURING THE MORNING PERIOD...PERPETUATION OF A
STABLE EASTERLY FLOW SUGGESTING MINIMAL POTENTIAL FOR THUNDERSTORMS.
HI RES MODEL GUIDANCE DOES HINT THAT SOME FORM OF TRAILING PV
FILAMENT AND/OR WEAK SURFACE TROUGH MAY THEN SHIFT ACROSS SE
MICHIGAN DURING PEAK HEATING. THIS IN THE PRESENCE OF SOME LEFT
EXIT REGION JET DYNAMICS MAY PROVE SUFFICIENT IN GENERATING A LOW
END COVERAGE OF SHOWERS /EMBEDDED THUNDER/ DURING THE MID-LATE
AFTERNOON. THE OVERALL SETUP REMAINS SOMEWHAT NEBULOUS AT THIS
STAGE WITH MOISTURE QUALITY AND DEGREE OF DESTABILIZATION AN
ISSUE...AND WILL SIMPLY PROVIDE A SLIGHT CHANCE MENTION. LITTLE
VARIATION IN THE TEMPERATURE PATTERN...WITH AT LEAST PARTIAL SUN
STILL SUPPORTING AFTERNOON HIGHS IN THE VICINITY OF 80 DEGREES.
ATTENTION HEADING INTO THE LATTER HALF OF THE WEEKEND TURNS TO
ANOTHER LOW AMPLITUDE SHORTWAVE EJECTING OVER THE MEAN SOUTHERN
PLAINS RIDGE. HIGH DEGREE OF VARIABILITY YET WITHIN THE MODEL
SOLUTION SPACE IN TERMS OF POTENTIAL STRENGTH...TIMING AND
POSITIONING OF THE ASSOCIATED LOW-MID LEVEL RESPONSE AS THIS SYSTEM
LIFTS EAST OF THE MISSISSIPPI. 12Z NAM TRENDING TOWARD A MUCH MORE
DYNAMIC SOLUTION...NETTING A MORE PRONOUNCED AND PROGRESSIVE
DOWNSTREAM EXPANSION OF LARGE SCALE ASCENT AND MOISTURE TRANSPORT
NORTH OF THE ATTENDANT WARM FRONTAL BOUNDARY AND INTO LOWER MICHIGAN
BY LATE SUNDAY. THIS SOLUTION SUGGESTS AN INCREASING POTENTIAL FOR
SHOWERS AND ELEVATED THUNDERSTORMS SUNDAY AFTERNOON AND EVENING.
HOWEVER 4 KM NAM AND CONSENSUS OF REMAINING GUIDANCE POINTS TOWARD A
MORE TEMPERED/SLOWER EVOLUTION...A GREATER WINDOW FOR PRECIPITATION
DEVELOPMENT HOLDING OFF UNTIL SUNDAY NIGHT/EARLY MONDAY. EVENTUAL
OUTCOME LIKELY CARRIES STRONG DEPENDENCE ON HOW CONVECTIVE TRENDS
EVOLVE UPSTREAM AND SPILL EASTWARD...SE MICHIGAN STILL SEEMINGLY
POSITIONED OUTSIDE OF THE GREATER INSTABILITY AXIS THROUGH THIS
PERIOD. FOR NOW...WILL HOLD TIGHT WITH A DRY FORECAST ON
SUNDAY...CENTERING POPS FOR SUNDAY NIGHT AND MONDAY. ASSUMING AN
EARLIER ONSET OF THICKER CLOUDINESS AND/OR PRECIPITATION NEVER
MATERIALIZES THROUGH PEAK HEATING...PERSISTENCE WILL LEAVE HIGHS
AGAIN WITHIN A COUPLE DEGREE OF 80F.
ZONAL FLOW ACROSS THE CORN BELT MONDAY EXPECTED TO AMPLIFY INTO A
TROUGH AS 80+ KT H25 JET STREAK DEVELOPS. WEAK CYCLOGENESIS ALONG
WITH SOME FORCING FROM FAVORABLE POSITIONING OF POLEWARD JET EXIT
REGION OVER THE LOWER GREAT LAKES ARGUES FOR AT LEAST CHANCE POPS
MONDAY. INSTABILITY LOOKS LIMITED WITH LI ONLY DROPPING TO AROUND
-2...SO HAVE CHC SHOWERS AND SLIGHT CHC T-STORMS. SURFACE CYCLONE
PROGGED TO INTENSIFY OVER THE NORTHEASTERN US WHICH FAVORS MORE
AGRESSIVE COLD/DRY AIR ADVECTION TUESDAY. UPPER TROUGH AMPLIFIES
OVER THE NORTHEASTERN US MIDWEEK WITH LOWER MI IN THE SUBSIDENCE
REGION UPSTREAM OF THE TROUGH. UPSHOT IS MAINLY DRY/COOL FORECAST
MIDWEEK.
&&
.MARINE...
MODEST NORTHEAST WINDS THROUGH THE EVENING WILL MAINTAIN SOME
ENHANCED WAVE DEVELOPMENT OVER THE NEARSHORE WATERS. GENERALLY
WEAKER EAST TO SOUTHEAST WINDS WILL THEN HOLD THROUGH THE WEEKEND AS
THE HIGH PRESSURE CENTER REMAINS POSITIONED JUST NORTHEAST OF THE
REGION.
&&
.AVIATION...ISSUED 110 PM EDT FRI AUG 7 2015
VFR THROUGH THE PERIOD WITH HIGH BASED CU THIS AFTN DISSIPATING WITH
THE LOSS OF HEATING THIS EVENING. LIGHT EAST WINDS WILL SUPPORT VERY
DRY RESIDENT COLUMN AND MAINTENANCE OF HIGH CEILINGS AS A WEAK UPPER
WAVE PASSES TONIGHT. A BRIEF PERIOD OF HIGH BASED RAIN SHOWERS WILL
BE POSSIBLE AT KMBS AND PERHAPS FNT LATE.
FOR DTW...SCATTERED TO BROKEN COVERAGE OF DIURNAL CU AT 4-5KFT
EXPECTED THIS AFTN BASED ON LATEST SATELLITE TRENDS AND OBS.
CU WILL DISSIPATE WITH THE ONSET OF NOCTURNAL STABILIZATION.
//DTW THRESHOLD PROBABILITIES...
* LOW FOR CIG AOB 5KFT
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
SHORT TERM...JVC
LONG TERM....MR/DT
MARINE.......MR
AVIATION.....JVC
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
110 PM EDT FRI AUG 7 2015
.AVIATION...
VFR THROUGH THE PERIOD WITH HIGH BASED CU THIS AFTN DISSIPATING WITH
THE LOSS OF HEATING THIS EVENING. LIGHT EAST WINDS WILL SUPPORT VERY
DRY RESIDENT COLUMN AND MAINTENANCE OF HIGH CEILINGS AS A WEAK UPPER
WAVE PASSES TONIGHT. A BRIEF PERIOD OF HIGH BASED RAIN SHOWERS WILL
BE POSSIBLE AT KMBS AND PERHAPS FNT LATE.
FOR DTW...SCATTERED TO BROKEN COVERAGE OF DIURNAL CU AT 4-5KFT
EXPECTED THIS AFTN BASED ON LATEST SATELLITE TRENDS AND OBS.
CU WILL DISSIPATE WITH THE ONSET OF NOCTURNAL STABILIZATION.
//DTW THRESHOLD PROBABILITIES...
* LOW FOR CIG AOB 5KFT
&&
.PREV DISCUSSION...ISSUED 846 AM EDT FRI AUG 7 2015
UPDATE...
QUICK UPDATE TO REMOVE CLOUD COVER FOR THIS MORNING BASED ON
SATELLITE TRENDS OVER THE LAST COUPLE OF HOURS AND PULL SCHC POPS
FOR THIS AFTERNOON ACROSS THE WEST AS WAA LOOKS TOO WEAK TO OVERCOME
THE DEEP LAYER OF VERY DRY AIR EVIDENT ON 12Z DTX SOUNDING. MID-
CLOUD AND DIURNAL CU WILL INCREASE BY LATE MORNING/EARLY AFTN
SUPPORTING CURRENT FORECAST HIGHS IN THE MID 70S TO AROUND 80, RIGHT
ABOUT NORMAL FOR EARLY AUGUST. UPDATE TO THE GRIDS AND ZFP
FORTHCOMING.
PREV DISCUSSION...ISSUED 254 AM EDT FRI AUG 7 2015
SHORT TERM...TODAY AND TONIGHT
UPPER SHORTWAVE OVER THE UPPER MIDWEST WILL TRACK ACROSS MICHIGAN
LATE TODAY AND TONIGHT AS IT RIDES ALONG THE NORTHERN PERIPHERY OF
AN UPPER RIDGE CENTERED OVER THE SOUTHERN PLAINS. THIS SHORTWAVE HAS
BEEN LOOKING MORE IMPRESSIVE ON WATER VAPOR AS THE NIGHT
PROGRESSES...AND HAS BEEN KICKING OFF A PRETTY GOOD COVERAGE OF
SHOWERS AND THUNDERSTORMS OVER MINNESOTA AND WISCONSIN. 00Z NAM/GFS
ONLY CREDIT THIS WAVE WITH A MODEST PUSH OF MID-LEVEL THETA-E
ADVECTION LATE TODAY/TONIGHT...AND LITTLE TO NO QPF OUTPUT OVER THE
AREA. ACTUALLY PREFER THE MORE AGRESSIVE SOLUTIONS SUCH AS THE
12Z/00Z EURO AND THE HRRR (EVEN THOUGH IT DOESN`T GO OUT QUITE FAR
ENOUGH YET) GIVEN APPEARANCE ON WATER VAPOR. INHERITED FORECAST WAS
ALREADY ON THE AGGRESSIVE SIDE AND CHANGES TO THE FORECAST WERE
MAINLY TO ADJUST TIMING AND INCREASE POPS SLIGHTLY OVER THE SAGINAW
VALLEY. SHOWERS AND PERHAPS A THUNDERSTORM COULD ARRIVE INTO THE
WESTERN PORTION OF THE FORECAST AREA AS EARLY AS 20Z/4PM. BEST
POTENTIAL STILL LOOKS BETWEEN BETWEEN 8PM AND 2AM...AHEAD OF THE
UPPER WAVE AS IT TRACKS INTO MICHIGAN. HIGHEST POPS OVERALL REMAIN
OVER THE SAGINAW VALLEY (MID-RANGE CHANCE)...AND THEN TAPER TO JUST
A SLIGHT CHANCE TOWARDS THE DETROIT AND ANN ARBOR AREAS. ALTHOUGH IT
IS ONLY 12-24 HOUR OUT...MODELS ARE STILL STRUGGLING A LITTLE WITH
TRACK AND TIMING OF THIS SMALL FEATURE. THIS LEADS TO LOWER
CONFIDENCE REGARDING COVERAGE AND TIMING OVERALL.
WITH PLENTY OF HIGH CLOUDS STREAMING IN AHEAD OF THIS UPPER WAVE FOR
THE EARLY PART OF THE DAY...AND A LIGHT EAST FLOW OFF THE
LAKES...EXPECT MAX TEMPERATURES TO CONTINUE RUNNING SLIGHTLY BELOW
NORMAL IN THE MID 70S TO NEAR 80. CLOUD COVER WILL THEN KEEP MIN
TEMPS MILD TONIGHT IN THE UPPER 50S TO LOW 60S.
LONG TERM...
ASIDE FROM A FEW LINGERING SHOWERS OVER THE NORTHERN FORECAST AREA
SATURDAY MORNING...EXPECT A BULK OF THE WEEKEND TO REMAIN DRY AS A
RIDGE OF SURFACE HIGH PRESSURE PERSISTS FROM EASTERN ONTARIO BACK
INTO LAKE HURON AND SOUTHEAST MICHIGAN. A SUBTLE SHORTWAVE RIDGE
WILL ALSO BUILD THROUGH THE AREA AS A FILLING UPPER LOW PRESSURE
SYSTEM LUMBERS EAST ACROSS SOUTHERN CANADA. THIS WILL PROVIDE A
SLIGHTLY WARMER AIRMASS AND ALLOW MAXIMUM TEMPERATURES TO CLIMB INTO
THE LOWER 80S IN MANY AREAS BOTH SATURDAY AND SUNDAY AFTERNOON.
AS THE AFOREMENTIONED RIDGE SHIFTS EAST OF THE AREA EARLY NEXT WEEK
AND MEAN TROUGH AXIS ASSOCIATED WITH WHAT STILL EXISTS OF SOUTHERN
CANADA UPPER LOW ENCROACHES ON THE CENTRAL GREAT LAKES...EXPECT RAIN
CHANCES TO INCREASE FROM SUNDAY EVENING/NIGHT INTO MONDAY. THIS WILL
BE FURTHER ENHANCED AS ADDITIONAL SHORTWAVE ENERGY CURRENTLY OFF THE
CALIFORNIA COAST GRADUALLY WORKS NORTHEAST INTO THE NORTHERN ROCKIES
AND PLAIN STATES AND IS EVENTUALLY FUNNELED INTO THE GREAT LAKES
AROUND THE SOUTHERN PERIPHERY OF LEAD SYSTEM IN CANADA.
ONCE EAST OF THE AREA BY MID NEXT WEEK...THIS SYSTEM WILL AMPLIFY
OVER EASTERN CANADA AND LEAD TO A RATHER NOTABLE UPPER TROUGH FROM
THE CENTRAL/EASTERN GREAT LAKES INTO EASTERN CANADA/NORTHEAST CONUS.
EXPECT DRIER WEATHER WITHIN NORTH/NORTHWEST FLOW ON THE BACK SIDE OF
THIS DEVELOPING TROUGH. THIS EVOLVING PATTERN WILL ALSO LEAD TO
COOLER READINGS ONCE AGAIN WITH MID 70S COMMON FOR AFTERNOON HIGH
TEMPERATURES MID/LATE NEXT WEEK.
MARINE...
HIGH PRESSURE CENTERED OVER LAKE HURON WILL SUSTAIN A LIGHT WIND
INTO TODAY...WITH JUST A MODEST INCREASE IN NORTHEAST WIND LATE IN
THE DAY LEADING TO SOME ENHANCED WAVE DEVELOPMENT OVER THE NEARSHORE
WATERS BY THIS EVENING. GENERALLY WEAKER EAST TO SOUTHEAST WINDS
WILL THEN HOLD THROUGH THE WEEKEND AS THE HIGH PRESSURE CENTER
REMAINS POSITIONED JUST NORTHEAST OF THE REGION.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....JVC
UPDATE.......JVC
SHORT TERM...HLO
LONG TERM....DG
MARINE.......DG
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
846 AM EDT FRI AUG 7 2015
.UPDATE...
QUICK UPDATE TO REMOVE CLOUD COVER FOR THIS MORNING BASED ON
SATELLITE TRENDS OVER THE LAST COUPLE OF HOURS AND PULL SCHC POPS
FOR THIS AFTERNOON ACROSS THE WEST AS WAA LOOKS TOO WEAK TO OVERCOME
THE DEEP LAYER OF VERY DRY AIR EVIDENT ON 12Z DTX SOUNDING. MID-
CLOUD AND DIURNAL CU WILL INCREASE BY LATE MORNING/EARLY AFTN
SUPPORTING CURRENT FORECAST HIGHS IN THE MID 70S TO AROUND 80, RIGHT
ABOUT NORMAL FOR EARLY AUGUST. UPDATE TO THE GRIDS AND ZFP
FORTHCOMING.
&&
.AVIATION...ISSUED 604 AM EDT FRI AUG 7 2015
AN UPPER LEVEL DISTURBANCE NEAR THE MINNESOTA/WISCONSIN BORDER WILL
TRACK EAST INTO MICHIGAN TODAY. THIS WILL BRING AN INCREASE IN
CLOUDS THROUGH THE DAY...AND PROVIDE A CHANCE FOR SHOWERS FROM VERY
LATE THIS AFTERNOON THROUGH TONIGHT. A THUNDERSTORM IS ALSO
POSSIBLE...BUT POTENTIAL IS LOW DUE TO LIMITED INSTABILITY. BEST
POTENTIAL FOR SHOWERS WILL BE FURTHER NORTH...NEAR MBS...WITH
CHANCES TAPERING OFF AS YOU MOVE SOUTHWARD. WITH COVERAGE EXPECTED
TO BE LOW OVERALL...MBS WAS THE ONLY TERMINAL TO INCLUDE A
PREVAILING LIGHT SHOWER MENTION IN THE 12Z TAFS.
FOR DTW...A FEW CLOUDS BETWEEN 5000-6000 FEET ARE ALREADY BEING
OBSERVED OVER WISCONSIN THIS MORNING AND SHOULD MOVE INTO THE AREA
AFTER 14Z. LATEST FORECAST MODEL DATA SUGGESTS DAYTIME HEATING AND
AN OVERALL INCREASE IN MOISTURE SHOULD PROVIDE A CEILING NEAR 5000
FEET STARTING AT AROUND 16Z...HOWEVER CONFIDENCE IS NOT HIGH. THIS
CEILING SHOULD BREAK AROUND 00Z AS WE LOSE HEATING. POTENTIAL FOR
SHOWERS THIS EVENING AND EARLY TONIGHT IS VERY LOW...AND NO MENTION
WAS INCLUDED IN THE TAF.
//DTW THRESHOLD PROBABILITIES...
* LOW CONFIDENCE WITH CEILINGS BELOW 5000 FEET THIS AFTERNOON AND
EARLY EVENING.
&&
.PREV DISCUSSION...ISSUED 254 AM EDT FRI AUG 7 2015
SHORT TERM...TODAY AND TONIGHT
UPPER SHORTWAVE OVER THE UPPER MIDWEST WILL TRACK ACROSS MICHIGAN
LATE TODAY AND TONIGHT AS IT RIDES ALONG THE NORTHERN PERIPHERY OF
AN UPPER RIDGE CENTERED OVER THE SOUTHERN PLAINS. THIS SHORTWAVE HAS
BEEN LOOKING MORE IMPRESSIVE ON WATER VAPOR AS THE NIGHT
PROGRESSES...AND HAS BEEN KICKING OFF A PRETTY GOOD COVERAGE OF
SHOWERS AND THUNDERSTORMS OVER MINNESOTA AND WISCONSIN. 00Z NAM/GFS
ONLY CREDIT THIS WAVE WITH A MODEST PUSH OF MID-LEVEL THETA-E
ADVECTION LATE TODAY/TONIGHT...AND LITTLE TO NO QPF OUTPUT OVER THE
AREA. ACTUALLY PREFER THE MORE AGRESSIVE SOLUTIONS SUCH AS THE
12Z/00Z EURO AND THE HRRR (EVEN THOUGH IT DOESN`T GO OUT QUITE FAR
ENOUGH YET) GIVEN APPEARANCE ON WATER VAPOR. INHERITED FORECAST WAS
ALREADY ON THE AGGRESSIVE SIDE AND CHANGES TO THE FORECAST WERE
MAINLY TO ADJUST TIMING AND INCREASE POPS SLIGHTLY OVER THE SAGINAW
VALLEY. SHOWERS AND PERHAPS A THUNDERSTORM COULD ARRIVE INTO THE
WESTERN PORTION OF THE FORECAST AREA AS EARLY AS 20Z/4PM. BEST
POTENTIAL STILL LOOKS BETWEEN BETWEEN 8PM AND 2AM...AHEAD OF THE
UPPER WAVE AS IT TRACKS INTO MICHIGAN. HIGHEST POPS OVERALL REMAIN
OVER THE SAGINAW VALLEY (MID-RANGE CHANCE)...AND THEN TAPER TO JUST
A SLIGHT CHANCE TOWARDS THE DETROIT AND ANN ARBOR AREAS. ALTHOUGH IT
IS ONLY 12-24 HOUR OUT...MODELS ARE STILL STRUGGLING A LITTLE WITH
TRACK AND TIMING OF THIS SMALL FEATURE. THIS LEADS TO LOWER
CONFIDENCE REGARDING COVERAGE AND TIMING OVERALL.
WITH PLENTY OF HIGH CLOUDS STREAMING IN AHEAD OF THIS UPPER WAVE FOR
THE EARLY PART OF THE DAY...AND A LIGHT EAST FLOW OFF THE
LAKES...EXPECT MAX TEMPERATURES TO CONTINUE RUNNING SLIGHTLY BELOW
NORMAL IN THE MID 70S TO NEAR 80. CLOUD COVER WILL THEN KEEP MIN
TEMPS MILD TONIGHT IN THE UPPER 50S TO LOW 60S.
LONG TERM...
ASIDE FROM A FEW LINGERING SHOWERS OVER THE NORTHERN FORECAST AREA
SATURDAY MORNING...EXPECT A BULK OF THE WEEKEND TO REMAIN DRY AS A
RIDGE OF SURFACE HIGH PRESSURE PERSISTS FROM EASTERN ONTARIO BACK
INTO LAKE HURON AND SOUTHEAST MICHIGAN. A SUBTLE SHORTWAVE RIDGE
WILL ALSO BUILD THROUGH THE AREA AS A FILLING UPPER LOW PRESSURE
SYSTEM LUMBERS EAST ACROSS SOUTHERN CANADA. THIS WILL PROVIDE A
SLIGHTLY WARMER AIRMASS AND ALLOW MAXIMUM TEMPERATURES TO CLIMB INTO
THE LOWER 80S IN MANY AREAS BOTH SATURDAY AND SUNDAY AFTERNOON.
AS THE AFOREMENTIONED RIDGE SHIFTS EAST OF THE AREA EARLY NEXT WEEK
AND MEAN TROUGH AXIS ASSOCIATED WITH WHAT STILL EXISTS OF SOUTHERN
CANADA UPPER LOW ENCROACHES ON THE CENTRAL GREAT LAKES...EXPECT RAIN
CHANCES TO INCREASE FROM SUNDAY EVENING/NIGHT INTO MONDAY. THIS WILL
BE FURTHER ENHANCED AS ADDITIONAL SHORTWAVE ENERGY CURRENTLY OFF THE
CALIFORNIA COAST GRADUALLY WORKS NORTHEAST INTO THE NORTHERN ROCKIES
AND PLAIN STATES AND IS EVENTUALLY FUNNELED INTO THE GREAT LAKES
AROUND THE SOUTHERN PERIPHERY OF LEAD SYSTEM IN CANADA.
ONCE EAST OF THE AREA BY MID NEXT WEEK...THIS SYSTEM WILL AMPLIFY
OVER EASTERN CANADA AND LEAD TO A RATHER NOTABLE UPPER TROUGH FROM
THE CENTRAL/EASTERN GREAT LAKES INTO EASTERN CANADA/NORTHEAST CONUS.
EXPECT DRIER WEATHER WITHIN NORTH/NORTHWEST FLOW ON THE BACK SIDE OF
THIS DEVELOPING TROUGH. THIS EVOLVING PATTERN WILL ALSO LEAD TO
COOLER READINGS ONCE AGAIN WITH MID 70S COMMON FOR AFTERNOON HIGH
TEMPERATURES MID/LATE NEXT WEEK.
MARINE...
HIGH PRESSURE CENTERED OVER LAKE HURON WILL SUSTAIN A LIGHT WIND
INTO TODAY...WITH JUST A MODEST INCREASE IN NORTHEAST WIND LATE IN
THE DAY LEADING TO SOME ENHANCED WAVE DEVELOPMENT OVER THE NEARSHORE
WATERS BY THIS EVENING. GENERALLY WEAKER EAST TO SOUTHEAST WINDS
WILL THEN HOLD THROUGH THE WEEKEND AS THE HIGH PRESSURE CENTER
REMAINS POSITIONED JUST NORTHEAST OF THE REGION.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
UPDATE.......JVC
AVIATION.....HLO
SHORT TERM...HLO
LONG TERM....DG
MARINE.......DG
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
604 AM EDT FRI AUG 7 2015
.AVIATION...
AN UPPER LEVEL DISTURBANCE NEAR THE MINNESOTA/WISCONSIN BORDER WILL
TRACK EAST INTO MICHIGAN TODAY. THIS WILL BRING AN INCREASE IN
CLOUDS THROUGH THE DAY...AND PROVIDE A CHANCE FOR SHOWERS FROM VERY
LATE THIS AFTERNOON THROUGH TONIGHT. A THUNDERSTORM IS ALSO
POSSIBLE...BUT POTENTIAL IS LOW DUE TO LIMITED INSTABILITY. BEST
POTENTIAL FOR SHOWERS WILL BE FURTHER NORTH...NEAR MBS...WITH
CHANCES TAPERING OFF AS YOU MOVE SOUTHWARD. WITH COVERAGE EXPECTED
TO BE LOW OVERALL...MBS WAS THE ONLY TERMINAL TO INCLUDE A
PREVAILING LIGHT SHOWER MENTION IN THE 12Z TAFS.
FOR DTW...A FEW CLOUDS BETWEEN 5000-6000 FEET ARE ALREADY BEING
OBSERVED OVER WISCONSIN THIS MORNING AND SHOULD MOVE INTO THE AREA
AFTER 14Z. LATEST FORECAST MODEL DATA SUGGESTS DAYTIME HEATING AND
AN OVERALL INCREASE IN MOISTURE SHOULD PROVIDE A CEILING NEAR 5000
FEET STARTING AT AROUND 16Z...HOWEVER CONFIDENCE IS NOT HIGH. THIS
CEILING SHOULD BREAK AROUND 00Z AS WE LOSE HEATING. POTENTIAL FOR
SHOWERS THIS EVENING AND EARLY TONIGHT IS VERY LOW...AND NO MENTION
WAS INCLUDED IN THE TAF.
//DTW THRESHOLD PROBABILITIES...
* LOW CONFIDENCE WITH CEILINGS BELOW 5000 FEET THIS AFTERNOON AND
EARLY EVENING.
&&
.PREV DISCUSSION...ISSUED 254 AM EDT FRI AUG 7 2015
SHORT TERM...TODAY AND TONIGHT
UPPER SHORTWAVE OVER THE UPPER MIDWEST WILL TRACK ACROSS MICHIGAN
LATE TODAY AND TONIGHT AS IT RIDES ALONG THE NORTHERN PERIPHERY OF
AN UPPER RIDGE CENTERED OVER THE SOUTHERN PLAINS. THIS SHORTWAVE HAS
BEEN LOOKING MORE IMPRESSIVE ON WATER VAPOR AS THE NIGHT
PROGRESSES...AND HAS BEEN KICKING OFF A PRETTY GOOD COVERAGE OF
SHOWERS AND THUNDERSTORMS OVER MINNESOTA AND WISCONSIN. 00Z NAM/GFS
ONLY CREDIT THIS WAVE WITH A MODEST PUSH OF MID-LEVEL THETA-E
ADVECTION LATE TODAY/TONIGHT...AND LITTLE TO NO QPF OUTPUT OVER THE
AREA. ACTUALLY PREFER THE MORE AGRESSIVE SOLUTIONS SUCH AS THE
12Z/00Z EURO AND THE HRRR (EVEN THOUGH IT DOESN`T GO OUT QUITE FAR
ENOUGH YET) GIVEN APPEARANCE ON WATER VAPOR. INHERITED FORECAST WAS
ALREADY ON THE AGGRESSIVE SIDE AND CHANGES TO THE FORECAST WERE
MAINLY TO ADJUST TIMING AND INCREASE POPS SLIGHTLY OVER THE SAGINAW
VALLEY. SHOWERS AND PERHAPS A THUNDERSTORM COULD ARRIVE INTO THE
WESTERN PORTION OF THE FORECAST AREA AS EARLY AS 20Z/4PM. BEST
POTENTIAL STILL LOOKS BETWEEN BETWEEN 8PM AND 2AM...AHEAD OF THE
UPPER WAVE AS IT TRACKS INTO MICHIGAN. HIGHEST POPS OVERALL REMAIN
OVER THE SAGINAW VALLEY (MID-RANGE CHANCE)...AND THEN TAPER TO JUST
A SLIGHT CHANCE TOWARDS THE DETROIT AND ANN ARBOR AREAS. ALTHOUGH IT
IS ONLY 12-24 HOUR OUT...MODELS ARE STILL STRUGGLING A LITTLE WITH
TRACK AND TIMING OF THIS SMALL FEATURE. THIS LEADS TO LOWER
CONFIDENCE REGARDING COVERAGE AND TIMING OVERALL.
WITH PLENTY OF HIGH CLOUDS STREAMING IN AHEAD OF THIS UPPER WAVE FOR
THE EARLY PART OF THE DAY...AND A LIGHT EAST FLOW OFF THE
LAKES...EXPECT MAX TEMPERATURES TO CONTINUE RUNNING SLIGHTLY BELOW
NORMAL IN THE MID 70S TO NEAR 80. CLOUD COVER WILL THEN KEEP MIN
TEMPS MILD TONIGHT IN THE UPPER 50S TO LOW 60S.
LONG TERM...
ASIDE FROM A FEW LINGERING SHOWERS OVER THE NORTHERN FORECAST AREA
SATURDAY MORNING...EXPECT A BULK OF THE WEEKEND TO REMAIN DRY AS A
RIDGE OF SURFACE HIGH PRESSURE PERSISTS FROM EASTERN ONTARIO BACK
INTO LAKE HURON AND SOUTHEAST MICHIGAN. A SUBTLE SHORTWAVE RIDGE
WILL ALSO BUILD THROUGH THE AREA AS A FILLING UPPER LOW PRESSURE
SYSTEM LUMBERS EAST ACROSS SOUTHERN CANADA. THIS WILL PROVIDE A
SLIGHTLY WARMER AIRMASS AND ALLOW MAXIMUM TEMPERATURES TO CLIMB INTO
THE LOWER 80S IN MANY AREAS BOTH SATURDAY AND SUNDAY AFTERNOON.
AS THE AFOREMENTIONED RIDGE SHIFTS EAST OF THE AREA EARLY NEXT WEEK
AND MEAN TROUGH AXIS ASSOCIATED WITH WHAT STILL EXISTS OF SOUTHERN
CANADA UPPER LOW ENCROACHES ON THE CENTRAL GREAT LAKES...EXPECT RAIN
CHANCES TO INCREASE FROM SUNDAY EVENING/NIGHT INTO MONDAY. THIS WILL
BE FURTHER ENHANCED AS ADDITIONAL SHORTWAVE ENERGY CURRENTLY OFF THE
CALIFORNIA COAST GRADUALLY WORKS NORTHEAST INTO THE NORTHERN ROCKIES
AND PLAIN STATES AND IS EVENTUALLY FUNNELED INTO THE GREAT LAKES
AROUND THE SOUTHERN PERIPHERY OF LEAD SYSTEM IN CANADA.
ONCE EAST OF THE AREA BY MID NEXT WEEK...THIS SYSTEM WILL AMPLIFY
OVER EASTERN CANADA AND LEAD TO A RATHER NOTABLE UPPER TROUGH FROM
THE CENTRAL/EASTERN GREAT LAKES INTO EASTERN CANADA/NORTHEAST CONUS.
EXPECT DRIER WEATHER WITHIN NORTH/NORTHWEST FLOW ON THE BACK SIDE OF
THIS DEVELOPING TROUGH. THIS EVOLVING PATTERN WILL ALSO LEAD TO
COOLER READINGS ONCE AGAIN WITH MID 70S COMMON FOR AFTERNOON HIGH
TEMPERATURES MID/LATE NEXT WEEK.
MARINE...
HIGH PRESSURE CENTERED OVER LAKE HURON WILL SUSTAIN A LIGHT WIND
INTO TODAY...WITH JUST A MODEST INCREASE IN NORTHEAST WIND LATE IN
THE DAY LEADING TO SOME ENHANCED WAVE DEVELOPMENT OVER THE NEARSHORE
WATERS BY THIS EVENING. GENERALLY WEAKER EAST TO SOUTHEAST WINDS
WILL THEN HOLD THROUGH THE WEEKEND AS THE HIGH PRESSURE CENTER
REMAINS POSITIONED JUST NORTHEAST OF THE REGION.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....HLO
SHORT TERM...HLO
LONG TERM....DG
MARINE.......DG
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
254 AM EDT FRI AUG 7 2015
.SHORT TERM...TODAY AND TONIGHT
UPPER SHORTWAVE OVER THE UPPER MIDWEST WILL TRACK ACROSS MICHIGAN
LATE TODAY AND TONIGHT AS IT RIDES ALONG THE NORTHERN PERIPHERY OF
AN UPPER RIDGE CENTERED OVER THE SOUTHERN PLAINS. THIS SHORTWAVE HAS
BEEN LOOKING MORE IMPRESSIVE ON WATER VAPOR AS THE NIGHT
PROGRESSES...AND HAS BEEN KICKING OFF A PRETTY GOOD COVERAGE OF
SHOWERS AND THUNDERSTORMS OVER MINNESOTA AND WISCONSIN. 00Z NAM/GFS
ONLY CREDIT THIS WAVE WITH A MODEST PUSH OF MID-LEVEL THETA-E
ADVECTION LATE TODAY/TONIGHT...AND LITTLE TO NO QPF OUTPUT OVER THE
AREA. ACTUALLY PREFER THE MORE AGRESSIVE SOLUTIONS SUCH AS THE
12Z/00Z EURO AND THE HRRR (EVEN THOUGH IT DOESN`T GO OUT QUITE FAR
ENOUGH YET) GIVEN APPEARANCE ON WATER VAPOR. INHERITED FORECAST WAS
ALREADY ON THE AGGRESSIVE SIDE AND CHANGES TO THE FORECAST WERE
MAINLY TO ADJUST TIMING AND INCREASE POPS SLIGHTLY OVER THE SAGINAW
VALLEY. SHOWERS AND PERHAPS A THUNDERSTORM COULD ARRIVE INTO THE
WESTERN PORTION OF THE FORECAST AREA AS EARLY AS 20Z/4PM. BEST
POTENTIAL STILL LOOKS BETWEEN BETWEEN 8PM AND 2AM...AHEAD OF THE
UPPER WAVE AS IT TRACKS INTO MICHIGAN. HIGHEST POPS OVERALL REMAIN
OVER THE SAGINAW VALLEY (MID-RANGE CHANCE)...AND THEN TAPER TO JUST
A SLIGHT CHANCE TOWARDS THE DETROIT AND ANN ARBOR AREAS. ALTHOUGH IT
IS ONLY 12-24 HOUR OUT...MODELS ARE STILL STRUGGLING A LITTLE WITH
TRACK AND TIMING OF THIS SMALL FEATURE. THIS LEADS TO LOWER
CONFIDENCE REGARDING COVERAGE AND TIMING OVERALL.
WITH PLENTY OF HIGH CLOUDS STREAMING IN AHEAD OF THIS UPPER WAVE FOR
THE EARLY PART OF THE DAY...AND A LIGHT EAST FLOW OFF THE
LAKES...EXPECT MAX TEMPERATURES TO CONTINUE RUNNING SLIGHTLY BELOW
NORMAL IN THE MID 70S TO NEAR 80. CLOUD COVER WILL THEN KEEP MIN
TEMPS MILD TONIGHT IN THE UPPER 50S TO LOW 60S.
&&
.LONG TERM...
ASIDE FROM A FEW LINGERING SHOWERS OVER THE NORTHERN FORECAST AREA
SATURDAY MORNING...EXPECT A BULK OF THE WEEKEND TO REMAIN DRY AS A
RIDGE OF SURFACE HIGH PRESSURE PERSISTS FROM EASTERN ONTARIO BACK
INTO LAKE HURON AND SOUTHEAST MICHIGAN. A SUBTLE SHORTWAVE RIDGE
WILL ALSO BUILD THROUGH THE AREA AS A FILLING UPPER LOW PRESSURE
SYSTEM LUMBERS EAST ACROSS SOUTHERN CANADA. THIS WILL PROVIDE A
SLIGHTLY WARMER AIRMASS AND ALLOW MAXIMUM TEMPERATURES TO CLIMB INTO
THE LOWER 80S IN MANY AREAS BOTH SATURDAY AND SUNDAY AFTERNOON.
AS THE AFOREMENTIONED RIDGE SHIFTS EAST OF THE AREA EARLY NEXT WEEK
AND MEAN TROUGH AXIS ASSOCIATED WITH WHAT STILL EXISTS OF SOUTHERN
CANADA UPPER LOW ENCROACHES ON THE CENTRAL GREAT LAKES...EXPECT RAIN
CHANCES TO INCREASE FROM SUNDAY EVENING/NIGHT INTO MONDAY. THIS WILL
BE FURTHER ENHANCED AS ADDITIONAL SHORTWAVE ENERGY CURRENTLY OFF THE
CALIFORNIA COAST GRADUALLY WORKS NORTHEAST INTO THE NORTHERN ROCKIES
AND PLAIN STATES AND IS EVENTUALLY FUNNELED INTO THE GREAT LAKES
AROUND THE SOUTHERN PERIPHERY OF LEAD SYSTEM IN CANADA.
ONCE EAST OF THE AREA BY MID NEXT WEEK...THIS SYSTEM WILL AMPLIFY
OVER EASTERN CANADA AND LEAD TO A RATHER NOTABLE UPPER TROUGH FROM
THE CENTRAL/EASTERN GREAT LAKES INTO EASTERN CANADA/NORTHEAST CONUS.
EXPECT DRIER WEATHER WITHIN NORTH/NORTHWEST FLOW ON THE BACK SIDE OF
THIS DEVELOPING TROUGH. THIS EVOLVING PATTERN WILL ALSO LEAD TO
COOLER READINGS ONCE AGAIN WITH MID 70S COMMON FOR AFTERNOON HIGH
TEMPERATURES MID/LATE NEXT WEEK.
&&
.MARINE...
HIGH PRESSURE CENTERED OVER LAKE HURON WILL SUSTAIN A LIGHT WIND
INTO TODAY...WITH JUST A MODEST INCREASE IN NORTHEAST WIND LATE IN
THE DAY LEADING TO SOME ENHANCED WAVE DEVELOPMENT OVER THE NEARSHORE
WATERS BY THIS EVENING. GENERALLY WEAKER EAST TO SOUTHEAST WINDS
WILL THEN HOLD THROUGH THE WEEKEND AS THE HIGH PRESSURE CENTER
REMAINS POSITIONED JUST NORTHEAST OF THE REGION.
&&
.AVIATION...ISSUED 1159 PM EDT THU AUG 6 2015
WEAK HIGH PRESSURE WILL REMAIN POSITIONED OVER SE MICHIGAN DURING
THE REST OF THE NIGHT AND THROUGH THE DAY/THURSDAY. WEAK LOW
PRESSURE OVER THE MIDWEST WILL SEND GENEROUS COVERAGE OF HIGH
CLOUDS OVER THE TERMINAL CORRIDOR WHICH WILL HELP PREVENT ANY
MEANINGFUL FOG AS THE WIND BECOMES LIGHT AND VARIABLE OR CALM
TOWARD SUNRISE. IF THERE IS ANY WIND...IT WILL BE LIGHT AND FROM
AN EASTERLY DIRECTION THROUGH THE DAY. VARYING AMOUNTS OF HIGH
CLOUDS WILL COMBINE WITH SOME POCKETS OF CUMULUS BY MID AFTERNOON
TO PRODUCE VFR CEILING ABOVE 5000 FEET AT TIMES. SPRINKLES OR
LIGHT RAIN SHOWERS MAY BE ABLE TO REACH THE FNT AND MBS AREAS
FRIDAY EVENING BUT WITH LOW COVERAGE EXPECTED AT THIS POINT WITH
NO RESTRICTIONS.
//DTW THRESHOLD PROBABILITIES...
* NONE.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
SHORT TERM...HLO
LONG TERM....DG
MARINE.......DG
AVIATION.....BT
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
1046 AM CDT FRI AUG 7 2015
.DISCUSSION...SEVERE TS WATCH 477 HAS BEEN POSTED GENERALLY FOR AREAS
EAST OF I-55 AND NORTH OF MS 16. DESPITE HRRR EXPECTATIONS THE MCS
MOVING ACROSS NORTH MS WOULD WEAKEN EARLIER THIS MORNING, IT HAS
PERSISTED AND IS NOW MOVING INTO AN INCREASINGLY UNSTABLE ENVIRONMENT
CHARACTERIZED BY SBCAPE IN THE 2000-3000 J/KG RANGE. IN ADDITION,
SOMEWHAT GREATER DEEP LAYER SHEAR EXISTS OVER THE NORTHEASTERN
PORTION OF THE AREA. CURRENT THINKING IS THIS REGIME WILL ALLOW THIS
COMPLEX TO CONTINUE SE-WARD OVER THE NEXT SEVERAL HOURS. PRIMARY
CONCERN IS DAMAGING WINDS, BUT CANNOT RULE OUT MARGINALLY SEVERE HAIL
GIVEN AMPLE INSTABILITY. HAZARD GRAPHICS/HWO WILL BE UPDATED TO
HIGHLIGHT THE AREA IN THE WATCH.
THE SHORT TERM FORECAST HAS BEEN UPDATED TO INCREASE POPS FOR AREAS
IN THE PATH OF THE ONGOING CONVECTION. THE RESULTING TEMP FORECAST
WILL BE PROBLEMATIC, BUT MADE AN EFFORT TO ACCOUNT FOR THE COOLING
THAT WILL TAKE PLACE IN THESE AREAS OVER THE NEXT FEW HOURS. UPDATED
PRODUCTS HAVE BEEN SENT. /DL/
&&
.AVIATION...VFR FLIGHT CATEGORIES ARE PREVAILING ONCE AGAIN AT TAF
SITES ACROSS THE REGION THIS MORNING. WITH HIGH CLOUDS..ASSOCIATED
WITH AN EAST SOUTHEAST MOVING COMPLEX OF STORMS CURRENTLY OVER NORTH
CENTRAL MISSISSIPPI...INCREASING FROM THE NORTH...VFR CATEGORIES ARE
EXPECTED TO PREVAIL AT MOST SITES THROUGH THE COURSE OF THE NEXT 24
HOURS. SHOWERS AND STORMS ARE EXPECTED TO BE MORE PREVALENT OVER
NORTH CENTRAL...NORTHEAST...AND EAST CENTRAL MISSISSIPPI TODAY...
PARTICULARLY THE GOLDEN TRIANGLE AREA WHICH COULD BE CLIPPED BY THE
AFORMENTIONED COMPLEX OF STORMS BY 17Z TODAY. STORMS WILL AGAIN
HAVE THE POTENTIAL OF PRODUCING DAMAGING WIND GUSTS OF 52 KNOTS...
ALONG WITH FREQUENT CLOUD TO GROUND LIGHTNING STRIKES AND HEAVY
DOWNPOURS. FLIGHT CATEGORIES WILL BRIEFLY BE REDUCED TO MVFR/IFR
STATUSES IF CONVECTION IS OBSERVED ON SITE. CONVECTION WILL BEGIN
TO WANE IN BOTH COVERAGE AND INTENSITY AROUND 00Z THIS EVENING...
WITH QUIET CONDITIONS EXPECTED TONIGHT INTO SATURDAY MORNING. /19/
&&
.PREV DISCUSSION... /ISSUED 419 AM CDT FRI AUG 7 2015/
SHORT TERM...TODAY THROUGH SATURDAY NIGHT...TODAY WILL BE SIMILAR TO
THURSDAY IN THAT HEAT AND HUMIDITY WILL REMAIN THE CONCERNS IN THE
WEST WHILE A STRONG TO SEVERE STORM OR TWO WILL AGAIN BE POSSIBLE IN
THE EAST THIS AFTERNOON AND EARLY EVENING. EARLY MORNING WATER VAPOR
IMAGERY/RAP ANALYSIS SHOWED THE CIRCULATION AROUND THE LARGE 594DAM
HIGH CENTERED OVER THE SOUTHERN PLAINS. A WEAK SHORTWAVE WAS NOTED
TOPPING THE HIGH AND SETTING OFF SOME CONVECTION OVER SOUTHWEST
MISSOURI. THIS SHORTWAVE IS EXPECTED TO CONTINUE TRACKING AROUND THE
PERIPHERY OF THE HIGH TODAY AND DROP OVER THE NORTHEAST PORTIONS OF
OUR CWA DURING PEAK HEATING. IT WILL COMBINE WITH OUR MOIST AIR MASS
AND A WEAK SURFACE BOUNDARY TO DEVELOP SOUTHEASTWARD MOVING STORMS
THIS AFTERNOON AND EVENING. A FEW STORMS WILL BE CAPABLE OF 50 TO 60
MPH WINDS. CURRENTLY THE SURFACE BOUNDARY WAS NOTED STALLED JUST
NORTH OF OUR CWA. A FEW SHOWERS WERE BEING DETECTED ON LOCAL RADARS
OVER OUR NORTHEAST MOST COUNTIES. SHOWERS AND A FEW STORMS WILL
REMAIN POSSIBLE OVER OUR NORTHEAST THIS MORNING BUT THIS BOUNDARY IS
EXPECTED TO SAG FARTHER SOUTH INTO OUR CWA AND BECOME ORIENTED
NORTHWEST TO SOUTHEAST BY AFTERNOON RESULTING IN THE MAIN AREA FOR
STRONG TO SEVERE STORMS EAST OF A GREENWOOD TO HATTIESBURG LINE. NO
RAIN IS EXPECTED IN OUR WEST TODAY WHERE TEMPERATURES WILL CONTINUE
TO TOP OUT A LITTLE WARMER THAN THURSDAY. COMBINED WITH THE HUMIDITY
PEAK HEAT INDEX VALUES WILL AGAIN BE 106 TO 110 WHERE A HEAT ADVISORY
WILL REMAIN IN EFFECT. THE LARGE MID LEVEL HIGH WILL BEGIN SHIFTING
EAST SATURDAY WHICH WILL FURTHER LIMIT RAIN CHANCES OVER OUR CWA AND
ALLOW FOR HOTTER TEMPERATURES. WL STILL MAINTAIN A MOIST AIR MASS
WHICH WILL RESULT IN MORE OF OUR CWA COMING UNDER A HEAT ADVISORY.
MODEL CONSENSUS STILL BREAKS OUT CONVECTION OVER OUR EAST THAT WILL
TRACK AROUND THE PERIPHERY OF THE HIGH. THIS ACTIVITY MAY NEGATE THE
EASTERN PORTIONS OF OUR FROM AN ADVISORY. HOWEVER...THE HIGHEST HEAT
INDEX VALUES ARE EXPECTED OVER OUR WEST AGAIN WHERE AN EXCESSIVE HEAT
WARNING MAY BE NEEDED FOR OUR SOUTHEAST ARKANSAS COUNTIES AND
NORTHEAST LOUISIANA PARISHES. AFTERNOON HIGHS ARE EXPECTED TO REACH
THE LOWER 100S THERE AND LEAD TO HEAT INDEX VALUES GREATER THAN 110.
/22/
LONG TERM...SUNDAY THROUGH THURSDAY...THE HOTTEST DAYS OF THE
SUMMER THUS FAR WILL LIKELY OCCUR ON SUNDAY AND MONDAY. THIS COMES
AS THE REGION REMAINS UNDER THE GRIP OF A 595DM UPPER RIDGE. THE
CENTER OF THE RIDGE WILL BE LOCATED ACROSS THE ARKLATEX REGION ON
SUNDAY BEFORE EVENTUALLY RETREATING A LITTLE FURTHER WEST ON MONDAY.
MODELS CONTINUE TO INDICATE THAT SUNDAY AND MONDAY SHOULD BE THE
HOTTEST WE HAVE SEEN THIS SUMMER WITH HIGHS EXCEEDING 100 DEGREES
AREAWIDE BOTH DAYS AND SOME LOCATIONS IN THE WEST EVEN NEARING 105
DEGREES ON MONDAY. NOT ONLY WILL THE ACTUAL AIR TEMPERATURE BE
DANGEROUS ENOUGH BUT THE COMBINATION OF HEAT AND HUMIDITY WILL MAKE
FOR OPPRESSIVE CONDITIONS. THE WESTERN HALF OF THE CWA WILL LIKELY
SEE HEAT INDICES OF 110-115 DEGREES ON SUNDAY AND MONDAY WHILE THE
REMAINDER OF THE CWA WILL BE AROUND 105-110 DEGREES. HEAT ADVISORIES
WILL MOST DEFINITELY BE ISSUED AND EXCESSIVE HEAT WARNINGS WILL BE
LIKELY FOR AT LEAST THE WESTERN AREAS IN LATER FORECAST PACKAGES.
THE CENTER OF THE RIDGE WILL CONTINUE TO TRACK WEST BUT THE REGION
WILL STILL GET HOT AS A COLD FRONT APPROACHES THE REGION FROM THE
NORTH. MODELS INDICATE A SLOW PROGRESSION INTO THE CWA AND COULD
SPARK SOME LATE AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS
ACROSS THE EASTERN PORTION OF THE FORECAST AREA ON MONDAY BUT MOST
LOCATIONS WILL BE DRY. AS THE UPPER RIDGE STRENGTHENS OVER WEST
TEXAS AND THE SOUTHERN PLAINS...THE ARKLAMISS REGION WILL COME UNDER
MORE OF A NORTHWEST FLOW REGIME WHICH WILL HELP DROP THE FRONT SOUTH
INTO AND MOSTLY THROUGH THE CWA ON TUESDAY. BETTER CHANCES OF
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE DURING THE AFTERNOON AND
EVENING HOURS WHICH SHOULD HELP BREAK THE OPPRESSIVE HEAT WE HAD
BEEN SEEING FOR SOME LOCATIONS. THE FRONT WILL STALL NEAR THE COAST
AND KEEP RAIN CHANCES CONFINED TO THE HIGHWAY 84 CORRIDOR AND SOUTH
ON WEDNESDAY. MODELS CONTINUE TO INDICATE THAT MUCH DRIER AIR WILL
MOVE SOUTH INTO THE CWA AS A SFC HIGH FROM CANADA MOVES INTO THE
OHIO VALLEY AND NOSES INTO THE NORTHERN PORTIONS OF THE CWA. AS THIS
OCCURS...AN UPPER LOW/TROUGH WILL TRACK SOUTHWEST ACROSS THE EASTERN
PORTION OF THE COUNTRY. PW VALUES ARE FORECAST TO DROP BELOW AN INCH
THROUGH THE END OF THE WEEK INTO NEXT WEEKEND...WITH EVEN SOME
VALUES AROUND A HALF OF AN INCH POSSIBLE. IN ADDITION...TEMPERATURES
LOOK TO DROP FURTHER FROM THE CENTURY MARK AND CLOSER TO WHAT WE
WOULD NORMALLY EXPECT FOR THIS TIME OF YEAR. DESPITE THE FACT THAT
RAIN CHANCES LOOK SLIM TO NONE IN THIS WEATHER PATTERN AND WITH THE
DRIER AIR...PERHAPS THIS IS OUR REWARD FROM MOTHER NATURES REWARD
FOR HAVING TO ENDURE THIS UPCOMING WEEKENDS OPPRESSIVE HEAT AND
HUMIDITY. /28/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 98 78 100 78 / 20 20 22 5
MERIDIAN 96 75 97 75 / 38 36 28 9
VICKSBURG 98 78 100 77 / 8 10 12 3
HATTIESBURG 99 78 98 77 / 24 24 31 13
NATCHEZ 97 78 98 77 / 6 8 14 4
GREENVILLE 98 78 100 78 / 20 17 12 3
GREENWOOD 97 76 98 77 / 54 25 13 3
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR MSZ018-019-034-035-
040>043-047>049-053-054-059.
LA...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR LAZ007>009-015-016-
023>026.
AR...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR ARZ074-075.
&&
$$
DL/19/22/28
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1059 PM CDT SAT AUG 8 2015
.UPDATE:
ISSUED AT 908 PM CDT SAT AUG 8 2015
LOW-MID LEVEL CLOUDINESS HAS EXPANDED AND ADVECTED SOUTHEASTWARD
THROUGH PORTIONS OF NORTHEAST AND EAST CENTRAL MO AND WEST
CENTRAL INTO SOUTHWEST IL IN A REGION OF 850 MB MOISTURE
CONVERGENCE. COULD NOT RULE OUT A FEW SPRINKLES OR LIGHT SHOWERS
FROM THESE CLOUDS. THE MORE SIGNIFICANT CONVECTION HAS BEGUN TO
DEVELOP ACROSS PARTS OF SOUTHEAST NEBRASKA...SOUTHWEST IA AND
NORTHWEST MO. THIS ACTIVITY WILL GROW UPSCALE INTO AN MCS AND MOVE
THROUGH NORTHEAST MO AND WEST CENTRAL IL LATE TONIGHT. THE LATEST
RUN OF THE HRRR AND THE NAM MODELS KEEP THIS ACTIVITY NORTH OF
I-70 THROUGH 12Z. LOW TEMPERATURES TONIGHT WILL BE WARMER THAN THE
PREVIOUS NIGHT DUE TO GREATER CLOUD COVER AND HIGHER SURFACE DEW
POINTS.
GKS
&&
.SHORT TERM: (TONIGHT AND SUNDAY)
ISSUED AT 320 PM CDT SAT AUG 8 2015
MAIN ISSUE FOR TONIGHT IS THE PROBABILITY OF THUNDERSTORMS IN
ASSOCIATION WITH ANTIPICATED UPSTREAM MCS DEVELOPMENT. STILL LOTS
OF UNCERTAINTY EXACTLY WHERE THE MCS WILL EVOLVE WITH A VARIETY OF
MODEL SOLUTIONS. THINKING AT THIS TIME IS THE MOST LIKELY REGION
FOR CONVECTIVE INITIATION IS IN THE VICINITY OF EXTREME NORTH
CENTRAL KS-SOUTHEAST NE NEAR THE JUXTAPOSITION OF SURFACE BOUNDARIES.
RATHER DEEP MOISTURE CONVERGENCE IS CURRENTLY FOCUSED IN THIS
REGION ASSOCIATED WITH THE BOUNDARIES AND SOUTHWESTERLY LLJ, AND
AN UPSTREAM SHORT WAVE EXITING THE CENTRAL ROCKIES WILL ADD LARGE
SCALE LIFT THIS EVENING. IT STILL APPEARS THAT CONVECTION WILL
EXPAND INTO SOUTHWEST IA AND EVOLVE INTO AN MCS. EAST-SOUTHEAST
ORIENTED DEEP LAYER SHEAR VECTORS AND FORWARD PROPAGATING MCS
MOTION VECTORS AND A VEERING LLJ SUGGEST THAT THE MCS WILL TRACK
E/SE AND IMPACT PARTS OF NORTHERN MO AND WEST CENTRAL IL. THE
SOUTHERN PERIPHERY OF THE MCS OR ADDITIONAL DEVELOPMENT WITH THE
OUTFLOW BOUNDARY COULD GET AS FAR SOUTH AS INTERSTATE 70 VERY LATE
TONIGHT.
THE UNCERTAINTY IN THE CONVECTION TONIGHT EXTENDS INTO SUNDAY, NOT
ONLY FOR THE LOCATION AND TIMING OF PRECIPITATION BUT ALSO THE
IMPACT ON ANY EXCESSIVE HEAT POTENTIAL AS WELL. THE MCS WHICH
MOVED ACROSS WESTERN MO THIS MORNING IS A CLASSIC EXAMPLE OF HOW
AN MCS CAN MESS UP A TEMP FORECAST. PRESENT INDICATIONS ARE THE
LONGEVITY AND SOUTHERN EXTENT OF SHOWERS AND THUNDERSTORMS ON
SUNDAY MORNING WILL BE GREATER THAN PREVIOUSLY THOUGHT AND THERE
IS INCREASING PROBABILITY THAT SCATTERED SHOWERS AND
THUNDERSTORMS WITH THE TRAILING MCS OUTFLOW BOUNDARY WILL IMPACT
THE ST. LOUIS AREA AND POINTS EAST, WITH THE THRUST OF MCS
RELATED SHOWERS/STORMS STAYING ACROSS WEST CENTRAL/CENTRAL IL.
WITH THE ANTICIPATION OF MORE CLOUDS, BOUNDARIES AND CONVECTION,
THE TEMPERATURES FOR MUCH OF THE AREA ARE A BIT COOLER AND MAX HEAT
INDICES LOWER IN THE 100-105 RANGE. THE HIGHEST READINGS ARE
LIKELY TO BE TO THE WEST/SOUTHWEST OF ST. LOUIS INTO MID MO. GIVEN
THE LESSER MAGNITUDE OF HEAT EXPECTED ON SUNDAY WE WONT BE REACHING
HEAT ADVISORY CRITERIA. LATER SHIFTS WILL NEED TO MONITOR THIS
CLOSELY IN CASE THE MCS AND IMPACTS ARE MUCH FURTHER NORTH WHICH
WOULD THEN INCREASE THE ODDS OF HIGHER TEMPS AND HI VALUES.
GLASS
.LONG TERM: (SUNDAY NIGHT THROUGH NEXT SATURDAY)
ISSUED AT 320 PM CDT SAT AUG 8 2015
THUNDERSTORM CHANCES RAMP UP ON SUNDAY NIGHT AS THE INITIAL EAST-
WEST COLD FRONT MOVES SOUTHWARD ACROSS THE REGION WITH THE MAIN
FOCUS ALONG THE I-70 CORRIDOR. WILL NEED TO MONITOR THIS AREA FOR
HEAVY RAIN POTENTIAL IN NEWER GUIDANCE TO SEE IF THE THREAT OF
PERSISTENT AND TRAINING STORMS BECOMES CLEARER. A SECONDARY COLD
FRONT THEN MOVES THROUGH THE AREA MONDAY AFTERNOON AND EVENING AND
THIS IS THE ONE THAT WILL REALLY BRING COOLER AND DRIER AIR INTO
THE REGION WITH SURFACE HIGH PRESSURE BUILDING IN ON TUESDAY.
SURFACE HIGH PRESSURE WILL THEN PERSIST MUCH OF THE REMAINDER OF
NEXT WEEK AS A HIGHLY AMPLIFIED UPPER AIR PATTERN AND IMPRESSIVE
EASTERN UPPER TROF DOMINATE, BRINGING SLIGHTLY BELOW AVERAGE
TEMPS AND LESSER HUMIDITY.
GLASS
&&
.AVIATION: (FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1038 PM CDT SAT AUG 8 2015
BAND OF LOW-MID LEVEL CLOUDINESS EXTENDING FROM UIN SOUTH-SOUTHEAST
INTO THE THE ST LOUIS METRO AREA SHOULD ADVECT EAST OF THE TAF
SITES BY 06Z SUNDAY. COMPLEX OF STORMS OVER SOUTHEAST
NEBRASKA...SOUTHWEST IA AND NORTHWEST MO IS FORECAST TO MOVE INTO
NORTHEAST MO AND WEST CENTRAL IL LATE TONIGHT/EARLY SUNDAY
MORNING. STILL SOME UNCERTAINTY AS TO THE SOUTHWARD EXTENT OF THE
CONVECTION, BUT THE LATEST MODEL GUIDANCE KEEPS IT NORTH OF COU
AND THE ST LOUIS METRO AREA AT LEAST THROUGH 12Z SUNDAY. WILL
INCLUDE A TEMPO GROUP OF TSRA FOR UIN TAF LATE TONIGHT/EARLY
SUNDAY MORNING. SCATTERED STORMS WILL LIKELY REDEVELOP ALONG
OUTFLOW BOUNDARY LEFTOVER FROM THE NOCTURNAL MCS SUNDAY AFTERNOON
AND EVENING PARTICULARLY FROM COU TO STL. SELY SURFACE WINDS
LATE TONIGHT WILL VEER AROUND TO A MORE SLY DIRECTION ON SUNDAY.
SPECIFICS FOR KSTL: MUCH OF THE MID LEVEL CLOUDINESS OVER STL
WILL ADVECT E OF STL BY 06Z SUNDAY...BUT THEN RETURN LATE
TONIGHT/EARLY SUNDAY MORNING AS AN MCS APPROACHES. A FEW STORMS
MAY DROP SOUTHEASTWARD INTO STL AREA SUNDAY MORNING...BUT IT
APPEARS THAT MOST OF THE CONVECTION WILL REMAIN NORTH OF STL.
ANOTHER ROUND OF CONVECTION IS EXPECTED LATE SUNDAY AFTERNOON AND
EVENING. SELY SURFACE WINDS LATE TONIGHT WILL BECOME MORE SLY ON
SUNDAY.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
922 PM CDT SAT AUG 8 2015
.UPDATE:
ISSUED AT 908 PM CDT SAT AUG 8 2015
LOW-MID LEVEL CLOUDINESS HAS EXPANDED AND ADVECTED SOUTHEASTWARD
THROUGH PORTIONS OF NORTHEAST AND EAST CENTRAL MO AND WEST
CENTRAL INTO SOUTHWEST IL IN A REGION OF 850 MB MOISTURE
CONVERGENCE. COULD NOT RULE OUT A FEW SPRINKLES OR LIGHT SHOWERS
FROM THESE CLOUDS. THE MORE SIGNIFICANT CONVECTION HAS BEGUN TO
DEVELOP ACROSS PARTS OF SOUTHEAST NEBRASKA...SOUTHWEST IA AND
NORTHWEST MO. THIS ACTIVITY WILL GROW UPSCALE INTO AN MCS AND MOVE
THROUGH NORTHEAST MO AND WEST CENTRAL IL LATE TONIGHT. THE LATEST
RUN OF THE HRRR AND THE NAM MODELS KEEP THIS ACTIVITY NORTH OF
I-70 THROUGH 12Z. LOW TEMPERATURES TONIGHT WILL BE WARMER THAN THE
PREVIOUS NIGHT DUE TO GREATER CLOUD COVER AND HIGHER SURFACE DEW
POINTS.
GKS
&&
.SHORT TERM: (TONIGHT AND SUNDAY)
ISSUED AT 320 PM CDT SAT AUG 8 2015
MAIN ISSUE FOR TONIGHT IS THE PROBABILITY OF THUNDERSTORMS IN
ASSOCIATION WITH ANTIPICATED UPSTREAM MCS DEVELOPMENT. STILL LOTS
OF UNCERTAINTY EXACTLY WHERE THE MCS WILL EVOLVE WITH A VARIETY OF
MODEL SOLUTIONS. THINKING AT THIS TIME IS THE MOST LIKELY REGION
FOR CONVECTIVE INITIATION IS IN THE VICINITY OF EXTREME NORTH
CENTRAL KS-SOUTHEAST NE NEAR THE JUXTAPOSITION OF SURFACE BOUNDARIES.
RATHER DEEP MOISTURE CONVERGENCE IS CURRENTLY FOCUSED IN THIS
REGION ASSOCIATED WITH THE BOUNDARIES AND SOUTHWESTERLY LLJ, AND
AN UPSTREAM SHORT WAVE EXITING THE CENTRAL ROCKIES WILL ADD LARGE
SCALE LIFT THIS EVENING. IT STILL APPEARS THAT CONVECTION WILL
EXPAND INTO SOUTHWEST IA AND EVOLVE INTO AN MCS. EAST-SOUTHEAST
ORIENTED DEEP LAYER SHEAR VECTORS AND FORWARD PROPAGATING MCS
MOTION VECTORS AND A VEERING LLJ SUGGEST THAT THE MCS WILL TRACK
E/SE AND IMPACT PARTS OF NORTHERN MO AND WEST CENTRAL IL. THE
SOUTHERN PERIPHERY OF THE MCS OR ADDITIONAL DEVELOPMENT WITH THE
OUTFLOW BOUNDARY COULD GET AS FAR SOUTH AS INTERSTATE 70 VERY LATE
TONIGHT.
THE UNCERTAINTY IN THE CONVECTION TONIGHT EXTENDS INTO SUNDAY, NOT
ONLY FOR THE LOCATION AND TIMING OF PRECIPITATION BUT ALSO THE
IMPACT ON ANY EXCESSIVE HEAT POTENTIAL AS WELL. THE MCS WHICH
MOVED ACROSS WESTERN MO THIS MORNING IS A CLASSIC EXAMPLE OF HOW
AN MCS CAN MESS UP A TEMP FORECAST. PRESENT INDICATIONS ARE THE
LONGEVITY AND SOUTHERN EXTENT OF SHOWERS AND THUNDERSTORMS ON
SUNDAY MORNING WILL BE GREATER THAN PREVIOUSLY THOUGHT AND THERE
IS INCREASING PROBABILITY THAT SCATTERED SHOWERS AND
THUNDERSTORMS WITH THE TRAILING MCS OUTFLOW BOUNDARY WILL IMPACT
THE ST. LOUIS AREA AND POINTS EAST, WITH THE THRUST OF MCS
RELATED SHOWERS/STORMS STAYING ACROSS WEST CENTRAL/CENTRAL IL.
WITH THE ANTICIPATION OF MORE CLOUDS, BOUNDARIES AND CONVECTION,
THE TEMPERATURES FOR MUCH OF THE AREA ARE A BIT COOLER AND MAX HEAT
INDICES LOWER IN THE 100-105 RANGE. THE HIGHEST READINGS ARE
LIKELY TO BE TO THE WEST/SOUTHWEST OF ST. LOUIS INTO MID MO. GIVEN
THE LESSER MAGNITUDE OF HEAT EXPECTED ON SUNDAY WE WONT BE REACHING
HEAT ADVISORY CRITERIA. LATER SHIFTS WILL NEED TO MONITOR THIS
CLOSELY IN CASE THE MCS AND IMPACTS ARE MUCH FURTHER NORTH WHICH
WOULD THEN INCREASE THE ODDS OF HIGHER TEMPS AND HI VALUES.
GLASS
.LONG TERM: (SUNDAY NIGHT THROUGH NEXT SATURDAY)
ISSUED AT 320 PM CDT SAT AUG 8 2015
THUNDERSTORM CHANCES RAMP UP ON SUNDAY NIGHT AS THE INITIAL EAST-
WEST COLD FRONT MOVES SOUTHWARD ACROSS THE REGION WITH THE MAIN
FOCUS ALONG THE I-70 CORRIDOR. WILL NEED TO MONITOR THIS AREA FOR
HEAVY RAIN POTENTIAL IN NEWER GUIDANCE TO SEE IF THE THREAT OF
PERSISTENT AND TRAINING STORMS BECOMES CLEARER. A SECONDARY COLD
FRONT THEN MOVES THROUGH THE AREA MONDAY AFTERNOON AND EVENING AND
THIS IS THE ONE THAT WILL REALLY BRING COOLER AND DRIER AIR INTO
THE REGION WITH SURFACE HIGH PRESSURE BUILDING IN ON TUESDAY.
SURFACE HIGH PRESSURE WILL THEN PERSIST MUCH OF THE REMAINDER OF
NEXT WEEK AS A HIGHLY AMPLIFIED UPPER AIR PATTERN AND IMPRESSIVE
EASTERN UPPER TROF DOMINATE, BRINGING SLIGHTLY BELOW AVERAGE
TEMPS AND LESSER HUMIDITY.
GLASS
&&
.AVIATION: (FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 539 PM CDT SAT AUG 8 2015
COMPLEX OF STORMS IS FORECAST TO MOVE ACROSS NORTHERN MO AND WEST
CENTRAL IL LATER THIS EVENING AND OVERNIGHT. UNCERTAINTY AS TO THE
SOUTHWARD EXTENT OF THE CONVECTION, SO FOR NOW WILL INCLUDE A
TEMPO GROUP OF TSRA FOR UIN TAF LATE TONIGHT AND JUST VCTS AT THE
OTHER TAF SITES. SCATTERED STORMS WILL LIKELY REDEVELOP ALONG
OUTFLOW BOUNDARY LEFTOVER FROM THE NOCTURNAL MCS SUNDAY AFTERNOON
INTO THE EVENING. SELY SURFACE WINDS TONIGHT WILL VEER AROUND TO A
MORE SLY DIRECTION ON SUNDAY.
SPECIFICS FOR KSTL: MUCH OF THE MID-UPPER LEVEL CLOUDINESS MAY
ADVECT E-SE OF STL LATER THIS EVENING...BUT THEN RETURN LATE
TONIGHT AS AN MCS APPROACHES. THUNDERSTORMS MAY DROP SOUTHEASTWARD
INTO STL AREA LATE TONIGHT/EARLY SUNDAY MORNING. ANOTHER ROUND OF
CONVECTION IS EXPECTED LATE SUNDAY AFTERNOON AND EVENING. SELY
SURFACE WINDS TONIGHT WILL BECOME MORE SLY ON SUNDAY.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
1157 AM CDT FRI AUG 7 2015
...18z Aviation Forecast Update...
.SHORT TERM...(Today and Tonight)
Issued at 0322 AM CDT FRI AUG 07 2015
Convection has developed over southwestern Missouri fueled by a
shortwave aloft and modest low level jet/moisture transport. HRRR
and RAP has good handle on this and pushes it southeast into south
central Missouri shortly after 12Z and should weaken and dissipate
through midday. After that, upper level high over the southern
plains and southwest conus will expand northeast towards the
Ozarks later today and tonight. This will be the beginning of
warming temperatures. Expect mainly sunny skies by this afternoon
which will aid in the rise. Expect warmest readings across
southeast Kansas into southwest Missouri where highs will be in
the lower to middle 90s, and just middle 80s over the eastern
Ozarks. Heat index values will flirt with advisory criteria for a
few hours this afternoon over southeast Kansas and southwest
Missouri, but will hold off on any headlines. A warm and humid
night is in store tonight with lows in the lower to middle 70s.
.LONG TERM...(Saturday through Thursday)
Issued at 0322 AM CDT FRI AUG 07 2015
Main forecast concern in this time frame is heat and heat index
values for both Saturday and Sunday and the need for any heat
related headlines. Upper ridge firmly in place across the Ozarks
both days. The hottest days looks to be Sunday with heat index
values in the 105 to 110 degree range. will likely need advisories
area-wide Sunday and perhaps only the western half of the forecast
area Saturday.
Medium range models continue to advertise a shortwave breaking down
the northern extent of the ridge Sunday night and Monday allowing
for a frontal boundary to make into the area. This will bring rain
chances back into the forecast, with the better chances across
central Missouri. It will also help cool temperatures off. This
wave should be east of the area later Monday with northwest flow
and surface high pressure nudging into the area for Tuesday
through Thursday, for cooler and quieter weather.
&&
.AVIATION...(For the 18Z TAFS through 18Z Saturday Afternoon)
Issued at 1155 AM CDT FRI AUG 07 2015
Pilots flying in and out of the local area can expect VFR
conditions. Winds will be light and variable becoming light
south-southeast tonight. There may be some light ground fog or
mist in the morning. Have a TEMPO group from 10z to 13z for MVFR
vis or 5sm for this potential.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
SHORT TERM...Raberding
LONG TERM...Raberding
AVIATION...Griffin
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
629 AM CDT FRI AUG 7 2015
.SHORT TERM...(Today and Tonight)
Issued at 0322 AM CDT FRI AUG 07 2015
Convection has developed over southwestern Missouri fueled by a
shortwave aloft and modest low level jet/moisture transport. HRRR
and RAP has good handle on this and pushes it southeast into south
central Missouri shortly after 12Z and should weaken and dissipate
through midday. After that, upper level high over the southern
plains and southwest conus will expand northeast towards the
Ozarks later today and tonight. This will be the beginning of
warming temperatures. Expect mainly sunny skies by this afternoon
which will aid in the rise. Expect warmest readings across
southeast Kansas into southwest Missouri where highs will be in
the lower to middle 90s, and just middle 80s over the eastern
Ozarks. Heat index values will flirt with advisory criteria for a
few hours this afternoon over southeast Kansas and southwest
Missouri, but will hold off on any headlines. A warm and humid
night is in store tonight with lows in the lower to middle 70s.
.LONG TERM...(Saturday through Thursday)
Issued at 0322 AM CDT FRI AUG 07 2015
Main forecast concern in this time frame is heat and heat index
values for both Saturday and Sunday and the need for any heat
related headlines. Upper ridge firmly in place across the Ozarks
both days. The hottest days looks to be Sunday with heat index
values in the 105 to 110 degree range. will likely need advisories
area-wide Sunday and perhaps only the western half of the forecast
area Saturday.
Medium range models continue to advertise a shortwave breaking down
the northern extent of the ridge Sunday night and Monday allowing
for a frontal boundary to make into the area. This will bring rain
chances back into the forecast, with the better chances across
central Missouri. It will also help cool temperatures off. This
wave should be east of the area later Monday with northwest flow
and surface high pressure nudging into the area for Tuesday
through Thursday, for cooler and quieter weather.
&&
.AVIATION...(For the 12Z TAFS through 12Z Saturday Morning)
Issued at 0629 AM CDT FRI AUG 07 2015
Convection will move east of the of KBBG and KSGF terminals by
14Z. After that ceilings will rise into the VFR category for the
remainder of the period as upper ridging builds into the area.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
SHORT TERM...Raberding
LONG TERM...Raberding
AVIATION...Raberding
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
324 AM CDT FRI AUG 7 2015
.SHORT TERM...(Today and Tonight)
Issued at 0322 AM CDT FRI AUG 07 2015
Convection has developed over southwestern Missouri fueled by a
shortwave aloft and modest low level jet/moisture transport. HRRR
and RAP has good handle on this and pushes it southeast into south
central Missouri shortly after 12Z and should weaken and dissipate
through midday. After that, upper level high over the southern
plains and southwest conus will expand northeast towards the
Ozarks later today and tonight. This will be the beginning of
warming temperatures. Expect mainly sunny skies by this afternoon
which will aid in the rise. Expect warmest readings across
southeast Kansas into southwest Missouri where highs will be in
the lower to middle 90s, and just middle 80s over the eastern
Ozarks. Heat index values will flirt with advisory criteria for a
few hours this afternoon over southeast Kansas and southwest
Missouri, but will hold off on any headlines. A warm and humid
night is in store tonight with lows in the lower to middle 70s.
.LONG TERM...(Saturday through Thursday)
Issued at 0322 AM CDT FRI AUG 07 2015
Main forecast concern in this time frame is heat and heat index
values for both Saturday and Sunday and the need for any heat
related headlines. Upper ridge firmly in place across the Ozarks
both days. The hottest days looks to be Sunday with heat index
values in the 105 to 110 degree range. will likely need advisories
area-wide Sunday and perhaps only the western half of the forecast
area Saturday.
Medium range models continue to advertise a shortwave breaking down
the northern extent of the ridge Sunday night and Monday allowing
for a frontal boundary to make into the area. This will bring rain
chances back into the forecast, with the better chances across
central Missouri. It will also help cool temperatures off. This
wave should be east of the area later Monday with northwest flow
and surface high pressure nudging into the area for Tuesday
through Thursday, for cooler and quieter weather.
&&
.AVIATION...(For the 06Z TAFS through 06Z Friday Night)
Issued at 1130 PM CDT THU AUG 06 2015
VFR conditions at area terminals will persist much of the
overnight. However changes are anticipated overnight as scattered
showers and thunderstorms develop from southeastern Kansas into
southwestern Missouri north of a warm front. This could result in
thunderstorms in the terminal vicinities and intervals of MVFR
conditions. The scattered storms will diminish by midday Friday as
the warm front lifts north. Expect an increase in southerly winds
by Friday afternoon.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
SHORT TERM...Raberding
LONG TERM...Raberding
AVIATION...Foster
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
621 PM CDT SAT AUG 8 2015
.SHORT TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 315 PM CDT SAT AUG 8 2015
NO BIG CHANGES FROM PREVIOUS THINKING...MAIN CONCERN IS POTENTIAL
FOR SEVERE WEATHER AND HEAVY RAIN. THE SEVERE THREAT WOULD MAINLY
BE PRIOR TO 06Z TONIGHT AND THEN ALSO LATE SUN AFTN/SUN EVENING.
HEAVY RAIN THREAT IS PRIOR TO ABOUT 08Z TONIGHT...AND MAINLY IN
SWRN IA.
JET PATTERN AT 12Z SHOWED 300 MB WINDS OF 50 TO 80 KNOTS FROM SRN
CA INTO SD/ND/MN. A 500 MB LOW WAS OVER SRN ID AT 12Z BUT WATER
VAPOR IMAGERY/RECENT RUC MODEL INITILIZATIONS SHOWED IT HAD MOVED
TO NEAR THE ID/MT/WY BORDER AREA AS OF EARLY THIS AFTN. THIS WILL
CONTINUE TO TRACK SLOWLY NEWD/EWD TONIGHT. THE 19Z KOAX SOUNDING
SHOWED THAT THE MID LEVELS HAD WARMED A BIT SINCE 12Z. OUR 12Z
700 MB TEMP WAS 7.6 C BUT HAD INCREASED TO 10.7 C AS OF 19Z.
19Z SPC MESOANALYSIS SHOWED THAT THERE WAS STILL QUITE A BIT OF
LOWEST 100 MB CONVECTIVE INHIBITION (MLCIN) AND MOST OF THE AREA
WAS NOT OVERLY UNSTABLE. HIGHEST MLCAPE WAS NEAR THE KS BORDER...
AROUND 2000 J/KG. CAP WAS WEAKEST FROM SWRN KS INTO PARTS OF CNTRL
KS AS OF MID AFTN...NEAR AND AHEAD OF SFC LOW PRES CENTER.
THERE REMAINS A CONDITIONAL THREAT OF SEVERE WEATHER FOR MOST OF
THE AREA. 0-6 KM SHEAR IS EXPECTED TO BE ADEQUATE FOR ROTATING
STORMS...BUT THERE IS SOME UNCERTAINTY AS TO WHEN AND WHERE
STRONG/SEVERE STORMS MAY FORM. THE MODELS OFFER VARYING SOLUTIONS.
ONE THING WE SAY IS THAT IT DOES APPEAR THAT BEST FOCUS WILL
SHIFT TO IA AND NRN MO LATER TONIGHT WITH A 30-50 KNOT LOW LEVEL
JET. LOWS SHOULD RANGE FROM MID 60S N TO AROUND 70 S.
WILL KEEP STORM CHANCES OVERNIGHT AND SUNDAY MORNING FOR AT LEAST
PARTS OF THE FCST AREA. BETTER POTENTIAL THOUGH APPEARS TO BE
LATER IN THE DAY ACRS OUR NRN ZONES...AS A FRONTAL SYSTEM DROPS
INTO THE AREA. KEPT SOME LOW POPS FOR LATE SUNDAY NIGHT AND MONDAY
BUT NOT IMPRESSED WITH RAIN POTENTIAL IN THOSE PERIODS FOR NOW...
ESPECIALLY MONDAY WHEN SURFACE RIDGE AXIS WILL BE BUILDING DOWN
ACROSS THE REGION.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 315 PM CDT SAT AUG 8 2015
PCPN CHANCES LOOK TO BE 14 PERCENT OR LESS FROM MONDAY NIGHT
ONWARD...SO FCST TEXT WILL NOT HAVE ANY MENTION OF TSTMS IN THOSE
PERIODS. 500 MB RIDGE IS EXPECTED TO BUILD W AND N FROM OK AND TX
MUCH OF THE WEEK...THEN FLATTEN A BIT BY NEXT WEEKEND AS TROUGH
MOVES EAST FROM THE PACIFIC NW AND NRN ROCKIES. LEFT A BLEND OF
GFS AND ECMWF TEMPS IN THE EXTENDED PERIOD...BUT HIGHS MAY END UP
BEING A BIT WARMER THAN THAT.
&&
.AVIATION...(00Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 618 PM CDT SAT AUG 8 2015
HAVE MOVED BACK TIMING OF POTENTIAL FOR SHOWERS TO AFFECT
KOMA/KLNK...AND STILL AM LOWER ON CONFIDENCE ABOUT WHETHER
SHOWERS/STORMS WILL BE IN THE VICINITY OF EITHER SITE...BUT
THOUGHT IT WARRANTED A MENTION OF AT LEAST SHOWERS FOR NOW. VFR
CONDITIONS ARE CURRENTLY IN PLACE...BUT MODELS CONTINUE TO HINT AT
A POTENTIAL FOR MVFR TO IFR STRATUS LATER TONIGHT/SUNDAY MORNING.
CONDITIONS SHOULD IMPROVE TO VFR BY AROUND MIDDAY AT ALL SITES.
WINDS WILL BE LIGHT AND VARIABLE TONIGHT...BECOMING SOUTHEASTERLY
UNDER 10KT BY SUNDAY AFTERNOON.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...MILLER
LONG TERM...MILLER
AVIATION...MAYES
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
315 PM CDT FRI AUG 7 2015
.SHORT TERM...(TONIGHT THROUGH MONDAY)
ISSUED AT 315 PM CDT FRI AUG 7 2015
THE PRIMARY FORECAST CONCERNS ARE IN REGARDS TO THE POTENTIAL FOR
TSTMS/RAIN LATER TONIGHT AND INTO SATURDAY...PLUS THE CHANCE OF
SEVERE WEATHER SATURDAY.
MAIN FEATURES FROM THE UPPER AIR MAPS THIS MORNING INCLUDED THE
FOLLOWING. AT 300 MB A 75 KT JET STREAK WAS OVER SRN CA PUNCHING TO
THE E/NE. THE 500 MB PATTERN IN GENERAL SHOWED TROUGHING ACROSS THE
W AND E COASTS AND A RIDGE CENTERED OVER TX/OK. CLOSED LOWS WERE
NOTED OVER SRN ALTA AND OVER CNTRL CA. 12 HOUR HEIGHT FALLS WERE
AROUND 50 METERS WITH THE CA SYSTEM...WHICH CONTINUED TO LIFT INTO
NV ACCORDING TO RECENT WATER VAPOR IMAGERY AND RECENT RUC MODEL
INITIALIZATIONS. A THERMAL RIDGE AT 700 MB EXTENDED FROM THE TX
PNHDL UP INTO CO. FAIRLY DECENT MOISTURE WAS NOTED AT 700 MB FROM
AZ INTO SRN NV WITH DEWPOINTS 5-8 DEGREES C. THE KOAX SOUNDING
THIS MORNING HAD ABOUT 0.94 INCHES OF PRECIPITABLE WATER (PW). THIS
WILL BE INCREASING OVER THE AREA TONIGHT. 12Z GFS SHOWED VALUES
APPROACHING 2 INCHES FOR MOST OF OUR AREA BY 12Z SAT AND NEAR 2.25
INCHES BY 00Z SUN. THE 12Z NAM WAS A BIT HIGHER AND MIGHT HAVE
BEEN A BIT OVERDONE.
PREVIOUS FORECAST TREND WAS FOR INCREASING POPS OVERNIGHT AND THAT
STILL SEEMS ON TRACK. WILL KEEP HIGHEST POPS PRIOR TO 12Z SAT OVER
ERN NE...SHIFTING HIGHEST NUMBERS TO NERN NE BY LATE MORNING. MID
LEVEL TEMPS ARE EXPECTED TO WARM SAT MORNING OVER THE SRN HALF OF
THE FCST AREA...SO SHIFTED HIGHEST POPS TO OUR WRN IA ZONES FOR THE
LATE AFTN AND EVENING. CONVECTIVE EVOLUTION AFTER THE MORNING STORMS
IS UNCERTAIN...BUT SHEAR PARAMETERS COULD BE FAVORABLE FOR SOME
SUPERCELLS IN THE AFTN AND EVENING. BEST SHOT FOR HEAVY RAIN WILL
BE ACROSS IOWA SATURDAY NIGHT.
STORM CHANCES SHOULD DIMINISH AFTER MIDNIGHT SATURDAY NIGHT...AND
SUNDAY RAIN CHANCES LOOK FAIRLY LOW. MID LEVEL RIDGE AXIS WILL START
TO BUILD FROM TX UP INTO SASK MONDAY WITH DECENT TROUGHING OVER THE
GREAT LAKES REGION.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 315 PM CDT FRI AUG 7 2015
A STRONG MID TROPOSPHERIC RIDGE WILL BE BUILDING AT THE START OF
THIS PERIOD OVER MID AMERICA. BY LATE WEEK...THE CENTER OF THE
ANTICYCLONE THAT STARTED OUT OVER TX/OK SHOULD RETROGRADE BACK
INTO NM AND CO. THIS PATTERN GENERALLY PRODUCES WARMER THAN NORMAL
TEMPERATURES (ESPECIALLY HIGHS) AND BELOW NORMAL PCPN. SO...BUMPED
UP HIGHS A BIT COMPARED TO A GFS/ECMWF BLEND.
&&
.AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 119 PM CDT FRI AUG 7 2015
VFR CONDITIONS ARE EXPECTED THROUGH THE AFTERNOON AND INTO
TONIGHT. A STORM SYSTEM MOVING INTO THE HIGH PLAINS WILL SPREAD
SHRA/TSRA EWD OVERNIGHT AND THIS ACTIVITY WILL LIKELY IMPACT ALL 3
TAF SITES /ESPECIALLY KOMA-KOFK/ LATE TONIGHT AND INTO SAT MRNG.
WILL INCLUDE PREVAILING CONDITIONS AT KOFK...AND TEMPO GROUPS AT
KOMA/KLNK. MVFR VSBY IS POSSIBLE IN THIS ACTIVITY. LIGHT WINDS
THIS AFTERNOON SHOULD BECOME SOUTHEAST THIS EVENING...BUT WILL
LIKELY BE VARIABLE AROUND RA LATE TONIGHT AND INTO SAT MRNG.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...MILLER
LONG TERM...MILLER
AVIATION...BOUSTEAD
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
341 AM CDT FRI AUG 7 2015
.SYNOPSIS...
ISSUED AT 341 AM CDT FRI AUG 7 2015
AT H5 UPPER RIDGE CENTERED OVER TEXAS WITH WEAK RIDGING INTO
NORTHERN PLAINS. THIS RIDGE IS BEING KNOCKED DOWN BY CLOSED LOW
ALONG THE CANADIAN BORDER. AN UPPER WAVE MOVING ACROSS WISCONSIN
INTO THE GREAT LAKES REGION AND ANOTHER WAVE...TROUGH OVER THE
CAROLINAS AND NORTHERN FLORIDA. CLOSED LOW MOVING ONSHORE IN
CENTRAL CALIFORNIA WITH MOISTURE STREAMING NORTH ALONG MEXICAN
COAST ON THE BACKSIDE OF THE RIDGE WRAPPING INTO LOW OVER
CALIFORNIA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 341 AM CDT FRI AUG 7 2015
MODELS DIFFER SOME IN THE SHORT TERM WITH NAM FAVORING A MORE
NORTHERLY TRACK FFOR WESTERN NEBRASKA BUT GFS AND GEM HAVE BEEN
FAVORING INTERSTATE 80 CORRIDOR THE LAST SEVERAL DAYS. GREETED BY
FOG AGAIN THIS MORNING BUT NOT AS DENSE OR WIDESPREAD AS THE LAST
SEVERAL DAYS. WILL BLEND THE GFS AND NAM SOLUTIONS. TIMING OF
WAVES MOVING THROUGH SOUTHWEST FLOW WILL BRING INITIATION OVER THE
WEST THROUGH THE AFTERNOON ALONG INVERTED SURFACE TROUGH ACROSS
THE PANHANDLE. 850MB LLJ KICKING IN EARLY AND MOVING EAST THROUGH
THE EARLY EVENING AND INCREASING TO AROUND 50KTS. STRONG WARM AIR
AND MOISTURE ADVECTION AHEAD OF THE SYSTEM THROUGH THE LATE
MORNING INTO EARLY EVENING. PWATS LAST NIGHT AROUND 11O PERCENT OF
NORMAL AT KLBF WITH 1.04 AND 127 PERCENT OF NORMAL AT KDDC WITH
1.28 INCHES. TDS IN THE MID 60S AND INCREASING INTO THE UPPER 60S
THIS AFTERNOON. OUTLOOKED WITH SLIGHT RISK ALL OF WESTERN
NEBRASKA. UPSLOPE FLOW...BULK SHEAR 30 TO 40KTS FAVORABLE FOR
SUPER CELL DEVELOPMENT. MU CAPE LATE AFTERNOON IN THE 2500-3000
J/KG. HIGHS AROUND 90 THIS AFTERNOON. FOG LAYER IS SHALLOW ENOUGH
THAT IT SHOULD NOT IMPEDE DAYTIME INSOLATION AS MUCH AS IT HAS THE
LAST SEVERAL DAYS. STRONG TO SEVERE STORMS EXPECTED TO CONGEAL
INTO MCS AND SHIFT EAST WITH THE LOW LEVEL JET AND UPPER FORCING.
EFFICIENT RAIN PROCESSES WILL KEEP THE FLASH FLOOD WATCH GOING
OVER THE WEST. HAVE INCLUDED MODERATE RAIN THROUGH THE AFTERNOON
AND THEN HEAVY RAIN THROUGH THE EVENING. LOWS IN THE 60S.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 341 AM CDT FRI AUG 7 2015
12Z SATURDAY AND BEYOND. THE MCS WILL CONTINUE ACROSS EASTERN
PORTIONS OF THE FORECAST AREA SATURDAY MORNING...WITH CLEARING
COMMENCING FROM WEST TO EAST. A GENERAL MODEL CONSENSUS WOULD
INDICATE ADDITIONAL QPF OF A FEW TENTHS OF AN INCH ACROSS NORTH
CENTRAL NEBRASKA...BUT NO MORE...THUS THE HEAVY RAIN THREAT WILL
DIMINISH AND SEE NO REASON TO EXTEND THE FLASH FLOOD WATCH BEYOND
11Z.
LATE AFTERNOON SATURDAY THE MODELS SEEM TO BE KEYING ON
ADDITIONAL DEVELOPMENT OF THUNDERSTORMS AS A DISTURBANCE/WAVE
WORKS IN CONJUNCTION WITH A LINGERING SURFACE TROUGH AND RIDGING
OF RICH THETA-E AIR ACROSS THE PANHANDLE. THE MAJORITY OF THE
QPF/HIGHEST CHANCES REMAIN OFF TO OUR NORTH AND WEST HOWEVER AS
THERE REMAINS LITTLE SUPPORT FOR A SUSTAINED COMPLEX. WILL
MAINTAIN THE HIGHEST POPS DURING THIS TIME PERIOD ACROSS NORTHWEST
NEBRASKA...BUT AT THAT WILL KEEP POPS AT 40 PERCENT OR LESS.
LINGERING CHANCES OF POPS TARGET MAINLY OUR NORTHERN ZONES ON
SUNDAY AS THE WAVE PROGRESSES EAST ACROSS THE NORTHERN PLAINS. A
WEAK BOUNDARY MAY SPARK OFF ADDITIONAL THUNDERSTORMS ACROSS OUR
EAST SUNDAY NIGHT AND INTO MONDAY...HOWEVER THE BEST MOISTURE AND
INSTABILITY ARE PROGGED TO BE EAST OF THE FORECAST AREA.
FOR NEXT WEEK...A WARMING AND DRYING TREND IS FORECAST AS LONGWAVE
RIDGING AMPLIFIES OVER THE CENTRAL CONUS...WITH BOOKEND VORTICIES
OVER THE NORTHWESTERN AND NORTHEASTERN COASTS. THE WARMEST
CONDITIONS APPEAR TO ARRIVE MID TO LATE WEEK WHEN TEMPERATURES
CLIMB ONCE AGAIN ABOVE AVERAGE. A CAPPING INVERSION IS SHOWN TO BE
QUITE STRONG DURING THE PERIOD...BUT A STEADY TAP OF LL MOISTURE
WOULD PROVIDE AT LEAST FOR A PERIODIC ISOLATED TO SCATTERED
MENTION OF STORMS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1128 PM CDT THU AUG 6 2015
FOG IS BEGINNING TO FORM IN THE PLATTE VALLEY AND REPUBLICAN
VALLEY. THE NAM...RAP AND HRRR SHOW FOG FORMING IN THESE AREAS AND
SPREADING NORTH AND WEST INTO THE SRN SANDHILLS TONIGHT. BURNOFF
IS EXPECTED BY 15Z-16Z. VFR IS EXPECTED THRU 16Z-21Z. THEREAFTER
THUNDERSTORMS SHOULD MOVE INTO WRN NEB...BECOME NUMEROUS...AND
SPREAD SOUTH AND EAST THROUGH THE FCST FRIDAY EVENING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH FROM THIS EVENING THROUGH LATE TONIGHT FOR
NEZ022-035>038-056>059-069>071.
&&
$$
SYNOPSIS...POWER
SHORT TERM...POWER
LONG TERM...JACOBS
AVIATION...CDC
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1128 PM CDT THU AUG 6 2015
.SYNOPSIS...
ISSUED AT 350 PM CDT THU AUG 6 2015
H5 ANALYSIS FROM THIS MORNING HAD A TROUGH OF LOW
PRESSURE EXTENDING FROM A CLOSED LOW OVER ALBERTA. THIS TROUGH
EXTENDED SWD INTO CENTRAL IDAHO. EAST OF THE TROUGH...A DECENT LEAD
SHORTWAVE EXTENDED ACROSS ERN MT INTO WESTERN SOUTH DAKOTA. ANOTHER
SHORTWAVE TROUGH EXTENDED FROM SERN WYOMING INTO EASTERN COLORADO.
HIGH PRESSURE REMAINED ANCHORED OVER ERN NEW MEXICO WITH A SECONDARY
LOW NOTED ACROSS THE LOWER OHIO VALLEY. AT THE SURFACE...LOW
PRESSURE WAS LOCATED OVER SOUTH CENTRAL SOUTH DAKOTA WITH A FRONTAL
BOUNDARY EXTENDING SWWD INTO THE SERN NEBRASKA PANHANDLE. EAST OF
THIS FEATURE...WINDS WERE SOUTHERLY AND DEW POINTS WERE IN THE MID
TO UPPER 60S. WEST OF THE FRONT...GUSTY NORTHWESTERLY WINDS AND MUCH
DRIER DEW POINTS IN THE 40S AND LOWER 50S WERE PRESENT ACROSS THE
NEBR PANHANDLE. THUNDERSTORMS FROM EARLIER THIS MORNING...HAD PUSHED
INTO SOUTH CENTRAL NEBRASKA AND NORTHERN KS. SKIES WERE MOSTLY CLEAR
IN THE WAKE OF THE THUNDERSTORMS FROM EARLIER TODAY...HOWEVER...A
STRIP OF LOW CLOUDS EXTENDED FROM SOUTHWESTERN NEBRASKA INTO THE
CENTRAL SANDHILLS. THIS CLOUD COVER HAS HELD TEMPS IN THE 70S THIS
AFTERNOON...WITH 80S NOTED ELSEWHERE.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 350 PM CDT THU AUG 6 2015
MAIN FORECAST CHALLENGE OVER THE NEXT 24 HOURS WILL BE THUNDERSTORM
CHANCES AS A WEAK UPPER LEVEL PV ANOMALY TRACKS ACROSS THE
DAKOTAS...WHICH WILL PUSH A COLD FRONT THROUGH THE CWA. AS OF 20Z
THE FRONT WAS SITUATED FROM NEAR MOBRIDGE SOUTH DAKOTA SOUTHWARD
THROUGH THE WESTERN SANDHILLS. CU FIELD HAS STEADILY DEEPENED ALONG
THE FRONT WITH SHOWERS AND THUNDERSTORMS DEVELOPING AS IT MOVES INTO
AN ENVIRONMENT THAT HAS BECOME INCREASINGLY UNSTABLE. MOST OF THE
CONVECTION HAS BEEN CONTAINED TO THE NE/SD BORDER AND POINTS
NORTHWARD. FURTHER DEVELOPMENT IS EXPECTED ALONG THE FRONT THROUGH
THE EVENING. THE SOUTHWARD EXTENT OF THE CONVECTION IS IN QUESTION
AS CURRENT MESOANALYSIS AND LAPS SOUNDINGS INDICATE A STRONG CAP
SOUTH OF HWY 2...A RESULT OF MORNING CONVECTION AND PERSISTENT
DAYTIME CLOUD COVER. MLCAPE HAS INCREASED TO AOA 1000 J/KG IN AREAS
THAT HAVE SEEN AMPLE SUNSHINE AND BL RECOVERY TODAY...MAINLY IN
NORTH CENTRAL NEBRASKA FROM AINSWORTH TO O`NEILL. DEEP LAYER SHEAR
IS SUPPORTIVE OF ORGANIZED ROBUST UPDRAFTS...SO THIS AREA WILL NEED
TO BE MONITORED FOR COUPLE STRONG TO SEVERE STORMS CAPABLE OF HAIL
AND GUSTY WINDS THROUGH THROUGH THE EVENING HOURS.
PRECIP CHANCES COME TO AN END BEHIND THE FRONT AS WINDS BECOME
NORTHWESTERLY AND DRIER AIR FILTERS IN FROM THE WEST. QUIET AND CALM
CONDITIONS ARE EXPECTED OVERNIGHT AS THE BOUNDARY LAYER DECOUPLES
AND LOCAL SURFACE PRESSURE TENDENCIES RELAX. LARGE SCALE SUBSIDENCE
IN THE WAKE OF THE DEPARTING PV MAX SHOULD CLEAR OUT THE MAJORITY OF
THE CLOUD OVER AS WELL.
SURFACE LEE SIDE TROUGH JUST EAST OF THE FRONT RANGE DEEPENS FRIDAY
AS DPVA INCREASES ALOFT IN ADVANCE OF THE NEXT SHORTWAVE TROUGH TO
IMPACT THE CENTRAL PLAINS. RESPONSE JUST TO THE EAST WILL BE
SOUTHERLY FLOW AND THE POLEWARD ADVECTION OF A VERY MOIST AIRMASS
INTO THE CWA. IN FACT...MODELS ARE IN SOLID AGREEMENT WITH H85
DEWPOINTS AS HIGH AS 16C TO 18C BY LATE AFTERNOON...NEAR THE
CLIMATOLOGY MAX FOR WESTERN NEBRASKA. THETA-E GRADIENT AND DEEP
MOISTURE CONVERGENCE FOCUSES ALONG THE SURFACE TROUGH WITH THE
APPROACH OF THE UPPER LEVEL SHORTWAVE...WHICH SHOULD BE ENOUGH TO
BREAK THE CAP AFTER 18Z OVER THE HIGH PLAINS OF EASTERN WY/CO/NEB
PANHANDLE. A FEW OF THE STORMS MAY MOVE INTO OUR WESTERN CWA BY LATE
AFTERNOON/EARLY EVENING. LARGE HAIL...STRONG GUSTY WINDS...AND HEAVY
RAINFALL WILL BE A CONCERN WITH ANY THUNDERSTORM...BUT THE MOST
WIDESPREAD ACTIVTY WILL MOST LIKELY OCCUR IN OUR CWA AFTER 00Z
SATURDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 350 PM CDT THU AUG 6 2015
FRIDAY NIGHT THROUGH SUNDAY...IN THE MID RANGE...THE
THREAT FOR HEAVY RAIN FRIDAY NIGHT INTO EARLY SATURDAY IS THE MAIN
FORECAST CONCERN. CONVECTION IS EXPECTED TO BE ONGOING LATE FRIDAY
AFTERNOON IN THE PANHANDLE. FURTHER EAST...THE CWA WILL BE FAIRLY
CAPPED FRIDAY AFTERNOON...SO CONVECTIVE INITIATION WILL BE ACROSS
THE NEBR PANHANDLE INVOF OF THE SURFACE TROUGH AND THETAE RIDGE
AXIS. BY EARLY EVENING...THIS CONVECTION WILL TRACK EAST INTO A VERY
MOIST LOW LEVEL ENVIRONMENT. H85 DEW POINTS REACH 14 TO 16C FRIDAY
AFTERNOON ACROSS THE WEST AND SWRN CWA WITH LAYER PWATS REACHING 1.5
TO 1.75 INCHES LATE FRIDAY AFTERNOON. THIS EQUATES TO THE 99TH
PERCENTILE FOR CLIMATOLOGY. THAT BEING SAID...THERE IS A HUGE AMOUNT
OF LOW LEVEL MOISTURE AVAILABLE FOR CONVECTION FRIDAY
AFTERNOON/EVENING. AS THIS CONVECTION MOVES EAST INTO SWRN NEBRASKA
BY EARLY EVENING...ABUNDANT DEEP LAYER SHEAR...ALONG WITH THE NOSE
OF AN H850 LOW LEVEL JET WILL COMBINE OVER SWRN NEBRASKA ENHANCING
CONVECTIVE DEVELOPMENT AS THE INITIAL THUNDERSTORMS MOVE EAST INTO
SWRN NEBRASKA. WITH THESE INGREDIENTS COMING TOGETHER...HEAVY RAIN
AND THE POSSIBILITY OF SEVERE STORMS LOOKS LIKE A DECENT BET FRIDAY
EVENING/FRIDAY NIGHT. THE LATEST NAM...GFS...AND SREF PUSH A MCS
ACROSS SWRN NEBRASKA FRIDAY EVENING INTO PORTIONS OF CENTRAL
NEBRASKA OVERNIGHT. GIVEN THE DEGREE OF MOISTURE...HEAVY RAIN LOOKS
LIKE A GOOD BET AND WITH THE FORECAST DEEP LAYER SHEAR OF 40+
KTS...STORMS HAVE A GOOD POTENTIAL TO BE SEVERE. WITH THE RECENT
HEAVY RAIN ACROSS SOUTHWESTERN NEBRASKA ON TUESDAY...AND ADDITIONAL
HEAVY RAIN IN CUSTER COUNTY FROM EARLIER TODAY...3 HR FFG HAS BEEN
RUNNING AROUND 1.5 INCHES...UP TO 2.0 INCHES. WITH THE NAM AND GFS
DEVELOPING 6 HR QPF`S OF 2 TO 4 INCHES...AND AFTER COORDINATING WITH
WPC...FELT IT NECESSARY TO HOIST A FLASH FLOOD WATCH FOR SWRN
NEBRASKA FOR FRIDAY NIGHT. GIVEN THE STRONG MODEL AGREEMENT WITH
THIS SYSTEM TOMORROW NIGHT...KEEP LIKELY POPS IN THE 70 TO 80
PERCENT RANGE ACROSS SWRN NEBRASKA AND WORDED THE FCST WITH HEAVY
RAIN...PARTICULARLY SOUTH OF A LINE FROM OSHKOSH TO SARGENT...WHERE
THE FLASH FLOOD WATCH WILL BE ISSUED FOR. FOR SATURDAY...CONVECTION
WILL LINGER INTO SATURDAY MORNING IN THE EASTERN CWA WITH MAINLY DRY
CONDS EXPECTED IN THE CENTRAL AND WEST. BY LATE AFTERNOON...THE
MODELS INITIATE CONVECTION IN THE PANHANDLE AND SWRN SD. THIS SEEMS
PLAUSIBLE AS THE THETA E RIDGE WILL BE ANCHORED ACROSS THE
PANHANDLE...AND A SURFACE TROUGH WILL LINGER IN THIS AREA AS WELL.
ATTM...NOT EXPECTING CONVECTION TO SUSTAIN ITSELF AFTER EVENING...AS
THE LOW LEVEL JET IS WEAK AND FOCUSED IN THE EASTERN PANHANDLE AND
WESTERN COUNTIES.
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY...THE LATEST LONG RANGE
MODEL SOLUTIONS...ARE TRENDING TOWARD THE DEVELOPMENT OF AN
AMPLIFIED RIDGE ACROSS THE ROCKIES OR CENTRAL PLAINS BEGINNING
EARLY NEXT WEEK. IF THIS CAN COME TO FRUITION...THE CURRENT WET
PATTERN WILL BEGIN TO DRY OUT EARLY NEXT WEEK...AND TEMPERATURES
WILL RETURN TO THE 90S. THE LATEST MEX GUIDANCE IS HINTING AT
WARMER TEMPS TOWARD THE END OF NEXT WEEK AND THIS IS SUPPORTED BY
THE ECMWF AS WELL...AS IT BUILDS A RIDGE ACROSS THE CENTRAL PLAINS
NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1128 PM CDT THU AUG 6 2015
FOG IS BEGINNING TO FORM IN THE PLATTE VALLEY AND REPUBLICAN
VALLEY. THE NAM...RAP AND HRRR SHOW FOG FORMING IN THESE AREAS AND
SPREADING NORTH AND WEST INTO THE SRN SANDHILLS TONIGHT. BURNOFF
IS EXPECTED BY 15Z-16Z. VFR IS EXPECTED THRU 16Z-21Z. THEREAFTER
THUNDERSTORMS SHOULD MOVE INTO WRN NEB...BECOME NUMEROUS...AND
SPREAD SOUTH AND EAST THROUGH THE FCST FRIDAY EVENING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH FROM FRIDAY EVENING THROUGH LATE FRIDAY NIGHT
FOR NEZ022-035>038-056>059-069>071.
&&
$$
SYNOPSIS...CLB
SHORT TERM...MARTIN
LONG TERM...CLB
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
1018 AM PDT FRI AUG 7 2015
.SYNOPSIS...MONSOON MOISTURE IN PLACE ACROSS THE REGION WILL BRING
CONTINUED CHANCES FOR SHOWERS AND THUNDERSTORMS TODAY. THUNDERSTORM
ACTIVITY WILL DECREASE FROM WEST TO EAST TODAY AS DRIER AIR PUSHES
INTO THE REGION FOR THE WEEKEND. ANOTHER ROUND OF MOISTURE MAY BE ON
TAP FOR THE MIDDLE OF NEXT WEEK.
&&
.UPDATE...THE LATEST OBSERVATION AND MODEL GUIDANCE TRENDS INDICATE
THERE WILL BE LITTLE TO NO CHANCE OF CONVECTION THE REST OF THE DAY
FROM CENTRAL CLARK COUNTY AND AREAS TO THE SOUTH AND WEST DUE TO
VERY STRONG SHEAR ALOFT AND INCREASINGLY DRY SOUTHWEST FLOW
SPREADING IN. ADJUSTMENTS WERE MADE TO THE POP/WX/QPF/SKY GRIDS
ACCORDINGLY. THUNDERSTORMS WILL CONTINUE TO BE FAST MOVING ACROSS
MOHAVE AND LINCOLN COUNTIES BUT TRAINING WILL BE A POSSIBILITY AND
THE FLASH FLOOD WATCH FOR THESE COUNTIES WILL REMAIN IN EFFECT
THROUGH THIS EVENING. THE REST OF THE FORECAST TRENDS AS DETAILED IN
THE PREVIOUS DISCUSSION LOOK FINE.
&&
.AVIATION...FOR MCCARRAN...DRIER AIR ALOFT SPREADING IN FROM THE
SOUTHWEST HAS DIMINISHED THE THREAT OF ADDITIONAL THUNDERSTORMS IN
THE TERMINAL AREA TODAY. NORTHEAST WINDS AROUND 10 KNOTS THROUGH
EARLY AFTERNOON WILL GIVE WAY TO SOUTHWEST WINDS WITH GUSTS OF 25-30
KTS BY MID TO LATE AFTERNOON. DRIER AND CALMER CONDITIONS ARE
EXPECTED THIS WEEKEND.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...ISOLATED TO SCATTERED THUNDERSTORMS WILL REMAIN
POSSIBLE TODAY...PRIMARILY IN AN ARC FROM THE SOUTHERN SIERRA ACROSS
CENTRA AND SOUTHEAST NEVADA INTO NORTHWEST ARIZONA. THIS LINE WILL
PUSH EAST THROUGH THE DAY WITH DRY CONDITIONS EXPECTED AREA WIDE BY
ROUGHLY 06Z SATURDAY. CIGS AROUND 6-8K FEET...GUSTY WINDS...HEAVY
RAIN WITH LOWERED VISIBILITY... STRONG TURBULENCE AND HAIL WILL ALL
BE POSSIBLE WITH STORMS. OUTSIDE OF THUNDERSTORM ACTIVITY EXPECT
GUSTY SOUTHWEST WINDS TO DEVELOP THIS AFTERNOON WITH SPEEDS OF 15-20
KTS AND GUSTS 25-30 KTS. &&
.PREV DISCUSSION...
245 AM PDT FRI AUG 7 2015
.SHORT TERM...TODAY THROUGH TONIGHT.
SIGNIFICANT MOISTURE HAS OVERSPREAD THE REGION WITH SURFACE
DEWPOINTS RANGING FROM THE UPPER 40`S ACROSS THE SOUTHERN GREAT
BASIN TO NEAR 70 ALONG THE COLORADO RIVER VALLEY NEAR LAKE HAVASU.
IPW SENSORS AND SPC MESOANALYSIS SHOW PRECIPITABLE WATER VALUES OF
1.5 TO NEARLY 2 INCHES ACROSS THE SOUTHEASTERN HALF OF THE FORECAST
AREA WHICH HAS MADE FOR EFFICIENT RAINFALL FROM STORMS OVERNIGHT.
FORTUNATELY STORM MOTION HAS BEEN AND WILL CONTINUE TO BE QUITE
RAPID AND THUS ONLY THE STRONGEST STORMS OR TRAINING STORMS HAVE
POSED A THREAT OF FLASH FLOODING. THE MAIN AREA OF ACTIVITY OVER THE
PAST 6 HOURS HAS BEEN OVER FAR EASTERN SAN BERNARDINO AND THE
SOUTHERN 2/3RDS OF MOHAVE COUNTY ASSOCIATED WITH DIVERGENCE AHEAD OF
AN APPROACHING UPPER LEVEL LOW ACTING ON A MODESTLY UNSTABLE
ATMOSPHERE. TO THE WEST OF THIS...ACTIVITY HAS BEEN MUCH WEAKER WITH
NUMEROUS WEAK SHOWERS AND VERY ISOLATED EMBEDDED THUNDERSTORMS.
VERY CHALLENGING FORECAST OVER THE NEXT 18 HOURS...ESPECIALLY WITH
RESPECT TO PRECIPITATION PLACEMENT. DRYING IS STILL EXPECTED TO
SWEEP FROM WEST TO EAST ACROSS THE REGION TODAY...WITH DRY
CONDITIONS EXPECTED AREA WIDE BY 06Z SATURDAY. HOWEVER...THE LATEST
HIGH-RES GUIDANCE HAS DELAYED DRYING ACROSS THE AREA BY 2-4 HOURS
COMPARED TO THE RUNS FROM YESTERDAY AFTERNOON AND EVENING...THIS MAY
BE IN PART DUE TO THE HIGHER THAN ANTICIPATED MOISTURE LEVELS
CURRENTLY IN PLACE. I HAVE TWEAKED THE FORECAST TO REFLECT THIS
DELAY. FOR INSTANCE...LAST EVENING IT APPEARED THAT THE BEST WINDOW
OF OPPORTUNITY FOR LAS VEGAS WOULD BE BETWEEN 11-16Z. HOWEVER THE
LATEST RUNS OF THE HRRR AND RAP HAVE SHUT MUCH OF THIS ACTIVITY
DOWN...AND HAVE BEGUN TO LATCH ON TO THE IDEA OF DELAYED DRYING. AS
A RESULT...THEY NOW INDICATE DECREASING ACTIVITY (WHICH IS CURRENTLY
BEING NOTED) BETWEEN NOW AND 16Z OR SO AND THEN AN INCREASING TREND
ALONG THE MOISTURE BOUNDARY BETWEEN 16-19Z...WITH THINGS FINALLY
PUSHING EAST OF THE VALLEY BY 22Z OR SO. MY CONFIDENCE IN THIS
SCENARIO IS MODERATE AT BEST...BUT IT DOES FIT WITH THE CURRENT
TRENDS AND OBSERVED MOISTURE IN PLACE AT THIS TIME. IN ANY
CASE...THE GENERAL THREATS WITH STORMS TODAY HAVEN`T CHANGED. THE
FLOOD THREAT WILL BE GREATEST TO THE SOUTH AND EAST OF LAS VEGAS
WHERE THE HIGHEST MOISTURE VALUES RESIDE. TO THE NORTH OF LAS VEGAS
THERE WILL BE AN INCREASED THREAT OF DAMAGING WIND GUSTS AND HAIL
DUE TO STRONG 0-6KM SHEAR AND SOMEWHAT DRIER AND COOLER AIR. IN
FACT...SPC NOW HAS A MARGINAL RISK OF SEVERE STORMS INDICATED ACROSS
THE ESMERALDA...NORTHERN NYE AND LINCOLN COUNTIES ON THEIR DAY 1
OUTLOOK DUE TO THE THREAT OF DAMAGING WINDS AND HAIL.
OUTSIDE OF THE THREAT FROM THUNDERSTORMS...WINDS COULD ALSO BE AN
ISSUE AS DRIER AT PUNCHES INTO THE REGION. THE WIND ADVISORY AND RED
FLAG WARNING IN PLACE FOR SOUTHERN/CENTRAL NYE AND FAR WESTERN CLARK
COUNTIES STILL LOOKS OK...BOTH WILL BE MARGINAL...BUT THE WIND IN
PARTICULAR IS ABNORMAL FOR THIS TIME OF YEAR SO NO CHANGES WILL BE
MADE.
.LONG TERM...SATURDAY THROUGH FRIDAY.
LATEST GUIDANCE IS TRYING TO DEVELOP SOME LIGHT PRECIP ACROSS THE
SIERRA SATURDAY AFTERNOON AND EARLY EVENING. HAVE INCREASED CLOUD
COVER FOR THIS AREA, BUT DID NOT MENTION PRECIP AT THIS TIME. WILL
MONITOR MODEL TRENDS WITH LINGERING MOISTURE IN THAT AREA THE NEXT
12 HOURS OR SO. OTHERWISE, DRY SOUTHWEST FLOW WILL TAKE HOLD THROUGH
MONDAY.
HIGH PRESSURE OVER TEXAS IS STILL ON TRACK TO EXPAND WEST TOWARD NEW
MEXICO STARTING LATE MONDAY. AT THE SAME TIME, A STRONG AREA OF LOW
PRESSURE WILL BUILD ALONG THE NORTHERN CALIFORNIA COAST. THE
COMBINATION OF THESE TWO FEATURES WILL PRODUCE SOUTHERLY FLOW OVER
OUR AREA. MOISTURE WILL TRACK NORTHWARD, MAINLY INTO MOHAVE COUNTY
TUESDAY, WITH SHOWERS AND THUNDERSTORMS POSSIBLE. SOUTHERLY FLOW
SHOULD STICK AROUND THROUGH THURSDAY, MAYBE INTO FRIDAY. MOISTURE
MAY SLIGHTLY EDGE WEST WEDNESDAY AND THURSDAY, BUT THAT WILL DEPEND
ON THE EVENTUAL POSITION OF THE WEST-COAST LOW. WITH PLENTY OF
UNCERTAINTY, DID NOT MAKE MANY CHANGES TO THE CURRENT FORECAST AT
THIS TIME.
AS FOR TEMPERATURES, MONDAY STILL APPEARS TO BE THE WARMEST DAY WITH
TEMPS A DEGREE OR TWO ABOVE NORMAL. OTHERWISE, NORMAL OR SLIGHTLY
BELOW NORMAL TEMPS ARE EXPECTED THROUGHOUT THE LONG-TERM PERIOD.
BREEZY SOUTH TO SOUTHWEST WINDS WILL BE COMMON EACH AFTERNOON AND
EARLY EVENING. WILL HAVE TO MONITOR THE EVENTUAL POSITION AND TRACK
OF THE WEST-COAST LOW AS WE COULD SEE LOCALLY WINDY CONDITIONS
ACROSS OUR NORTHERN FORECAST AREA TUESDAY THROUGH THURSDAY.
&&
.FIRE WEATHER...DRIER AIR WILL PUSH FROM WEST TO EAST ACROSS THE
REGION TODAY. THIS WILL LOWER RH`S TO CRITICAL LEVELS FRIDAY
AFTERNOON AND COMBINE WITH GUSTY WINDS ACROSS MUCH OF CENTRAL AND
SOUTHERN NYE COUNTY TO BRING CRITICAL FIRE CONDITIONS TO THE ZONE
462. IT APPEARS THAT THIS AREA HAS RECEIVED LITTLE PRECIPITATION AND
CURRENT FUEL CONDITIONS WARRANT THE RED FLAG WARNING FOR THIS
AFTERNOON INTO THIS EVENING.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
UPDATE/AVIATION...ADAIR
SHORT TERM........WOLCOTT
LONG TERM.........PADDOCK
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
245 AM PDT FRI AUG 7 2015
.SYNOPSIS...MONSOON MOISTURE IN PLACE ACROSS THE REGION WILL BRING
CONTINUED CHANCES FOR SHOWERS AND THUNDERSTORMS TODAY. THUNDERSTORM
ACTIVITY WILL DECREASE FROM WEST TO EAST TODAY AS DRIER AIR PUSHES
INTO THE REGION FOR THE WEEKEND. ANOTHER ROUND OF MOISTURE MAY BE ON
TAP FOR THE MIDDLE OF NEXT WEEK.
&&
.SHORT TERM...TODAY THROUGH TONIGHT.
SIGNIFICANT MOISTURE HAS OVERSPREAD THE REGION WITH SURFACE
DEWPOINTS RANGING FROM THE UPPER 40`S ACROSS THE SOUTHERN GREAT
BASIN TO NEAR 70 ALONG THE COLORADO RIVER VALLEY NEAR LAKE HAVASU.
IPW SENSORS AND SPC MESOANALYSIS SHOW PRECIPITABLE WATER VALUES OF
1.5 TO NEARLY 2 INCHES ACROSS THE SOUTHEASTERN HALF OF THE FORECAST
AREA WHICH HAS MADE FOR EFFICIENT RAINFALL FROM STORMS OVERNIGHT.
FORTUNATELY STORM MOTION HAS BEEN AND WILL CONTINUE TO BE QUITE
RAPID AND THUS ONLY THE STRONGEST STORMS OR TRAINING STORMS HAVE
POSED A THREAT OF FLASH FLOODING. THE MAIN AREA OF ACTIVITY OVER THE
PAST 6 HOURS HAS BEEN OVER FAR EASTERN SAN BERNARDINO AND THE
SOUTHERN 2/3RDS OF MOHAVE COUNTY ASSOCIATED WITH DIVERGENCE AHEAD OF
AN APPROACHING UPPER LEVEL LOW ACTING ON A MODESTLY UNSTABLE
ATMOSPHERE. TO THE WEST OF THIS...ACTIVITY HAS BEEN MUCH WEAKER WITH
NUMEROUS WEAK SHOWERS AND VERY ISOLATED EMBEDDED THUNDERSTORMS.
VERY CHALLENGING FORECAST OVER THE NEXT 18 HOURS...ESPECIALLY WITH
RESPECT TO PRECIPITATION PLACEMENT. DRYING IS STILL EXPECTED TO
SWEEP FROM WEST TO EAST ACROSS THE REGION TODAY...WITH DRY
CONDITIONS EXPECTED AREA WIDE BY 06Z SATURDAY. HOWEVER...THE LATEST
HIGH-RES GUIDANCE HAS DELAYED DRYING ACROSS THE AREA BY 2-4 HOURS
COMPARED TO THE RUNS FROM YESTERDAY AFTERNOON AND EVENING...THIS MAY
BE IN PART DUE TO THE HIGHER THAN ANTICIPATED MOISTURE LEVELS
CURRENTLY IN PLACE. I HAVE TWEAKED THE FORECAST TO REFLECT THIS
DELAY. FOR INSTANCE...LAST EVENING IT APPEARED THAT THE BEST WINDOW
OF OPPORTUNITY FOR LAS VEGAS WOULD BE BETWEEN 11-16Z. HOWEVER THE
LATEST RUNS OF THE HRRR AND RAP HAVE SHUT MUCH OF THIS ACTIVITY
DOWN...AND HAVE BEGUN TO LATCH ON TO THE IDEA OF DELAYED DRYING. AS
A RESULT...THEY NOW INDICATE DECREASING ACTIVITY (WHICH IS CURRENTLY
BEING NOTED) BETWEEN NOW AND 16Z OR SO AND THEN AN INCREASING TREND
ALONG THE MOISTURE BOUNDARY BETWEEN 16-19Z...WITH THINGS FINALLY
PUSHING EAST OF THE VALLEY BY 22Z OR SO. MY CONFIDENCE IN THIS
SCENARIO IS MODERATE AT BEST...BUT IT DOES FIT WITH THE CURRENT
TRENDS AND OBSERVED MOISTURE IN PLACE AT THIS TIME. IN ANY
CASE...THE GENERAL THREATS WITH STORMS TODAY HAVEN`T CHANGED. THE
FLOOD THREAT WILL BE GREATEST TO THE SOUTH AND EAST OF LAS VEGAS
WHERE THE HIGHEST MOISTURE VALUES RESIDE. TO THE NORTH OF LAS VEGAS
THERE WILL BE AN INCREASED THREAT OF DAMAGING WIND GUSTS AND HAIL
DUE TO STRONG 0-6KM SHEAR AND SOMEWHAT DRIER AND COOLER AIR. IN
FACT...SPC NOW HAS A MARGINAL RISK OF SEVERE STORMS INDICATED ACROSS
THE ESMERALDA...NORTHERN NYE AND LINCOLN COUNTIES ON THEIR DAY 1
OUTLOOK DUE TO THE THREAT OF DAMAGING WINDS AND HAIL.
OUTSIDE OF THE THREAT FROM THUNDERSTORMS...WINDS COULD ALSO BE AN
ISSUE AS DRIER AT PUNCHES INTO THE REGION. THE WIND ADVISORY AND RED
FLAG WARNING IN PLACE FOR SOUTHERN/CENTRAL NYE AND FAR WESTERN CLARK
COUNTIES STILL LOOKS OK...BOTH WILL BE MARGINAL...BUT THE WIND IN
PARTICULAR IS ABNORMAL FOR THIS TIME OF YEAR SO NO CHANGES WILL BE
MADE.
.LONG TERM...SATURDAY THROUGH FRIDAY.
LATEST GUIDANCE IS TRYING TO DEVELOP SOME LIGHT PRECIP ACROSS THE
SIERRA SATURDAY AFTERNOON AND EARLY EVENING. HAVE INCREASED CLOUD
COVER FOR THIS AREA, BUT DID NOT MENTION PRECIP AT THIS TIME. WILL
MONITOR MODEL TRENDS WITH LINGERING MOISTURE IN THAT AREA THE NEXT
12 HOURS OR SO. OTHERWISE, DRY SOUTHWEST FLOW WILL TAKE HOLD THROUGH
MONDAY.
HIGH PRESSURE OVER TEXAS IS STILL ON TRACK TO EXPAND WEST TOWARD NEW
MEXICO STARTING LATE MONDAY. AT THE SAME TIME, A STRONG AREA OF LOW
PRESSURE WILL BUILD ALONG THE NORTHERN CALIFORNIA COAST. THE
COMBINATION OF THESE TWO FEATURES WILL PRODUCE SOUTHERLY FLOW OVER
OUR AREA. MOISTURE WILL TRACK NORTHWARD, MAINLY INTO MOHAVE COUNTY
TUESDAY, WITH SHOWERS AND THUNDERSTORMS POSSIBLE. SOUTHERLY FLOW
SHOULD STICK AROUND THROUGH THURSDAY, MAYBE INTO FRIDAY. MOISTURE
MAY SLIGHTLY EDGE WEST WEDNESDAY AND THURSDAY, BUT THAT WILL DEPEND
ON THE EVENTUAL POSITION OF THE WEST-COAST LOW. WITH PLENTY OF
UNCERTAINTY, DID NOT MAKE MANY CHANGES TO THE CURRENT FORECAST AT
THIS TIME.
AS FOR TEMPERATURES, MONDAY STILL APPEARS TO BE THE WARMEST DAY WITH
TEMPS A DEGREE OR TWO ABOVE NORMAL. OTHERWISE, NORMAL OR SLIGHTLY
BELOW NORMAL TEMPS ARE EXPECTED THROUGHOUT THE LONG-TERM PERIOD.
BREEZY SOUTH TO SOUTHWEST WINDS WILL BE COMMON EACH AFTERNOON AND
EARLY EVENING. WILL HAVE TO MONITOR THE EVENTUAL POSITION AND TRACK
OF THE WEST-COAST LOW AS WE COULD SEE LOCALLY WINDY CONDITIONS
ACROSS OUR NORTHERN FORECAST AREA TUESDAY THROUGH THURSDAY.
&&
.AVIATION...FOR MCCARRAN...LIGHT NORTHEAST WINDS WERE PERSISTING AT
MCCARRAN DUE TO THUNDERSTORM OUTFLOW FROM LAST EVENING. SHOWERS WILL
CONTINUE TO DRIFT ACROSS THE LAS VEGAS VALLEY THROUGH AT LEAST 12Z.
CONFIDENCE IN THUNDERSTORM ACTIVITY BEYOND THIS IS RELATIVELY
LOW...BUT CHANCES WILL EXIST THROUGH ROUGHLY 22Z BEFORE DRIER AIR
PUSHES THROUGH. CIGS AROUND 8K FEET...GUSTY WINDS...HEAVY RAIN WITH
LOWERED VISIBILITY...TURBULENCE AND HAIL WILL ALL BE POSSIBLE WITH
STORMS. SOUTHWEST WINDS ARE EXPECTED TO INCREASE DURING THE
AFTERNOON AND GUSTS TO 25-30 KTS ARE LIKELY. DRIER AND CALMER
CONDITIONS ARE EXPECTED THIS WEEKEND.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...ISOLATED TO SCATTERED THUNDERSTORMS WILL REMAIN
POSSIBLE TODAY...PRIMARILY NORTH AND EAST OF A KNXP-KDRA-KBIH LINE.
THIS LINE WILL PUSH EAST THROUGH THE DAY WITH DRY CONDITIONS
EXPECTED AREA WIDE BY ROUGHLY 06Z SATURDAY. CIGS AROUND 6-8K
FEET...GUSTY WINDS...HEAVY RAIN WITH LOWERED VISIBILITY... STRONG
TURBULENCE AND HAIL WILL ALL BE POSSIBLE WITH STORMS. OUTSIDE OF
THUNDERSTORM ACTIVITY EXPECT GUSTY SOUTHWEST WINDS TO DEVELOP THIS
AFTERNOON WITH SPEEDS OF 15-20 KTS AND GUSTS 25-30 KTS.
&&
.FIRE WEATHER...DRIER AIR WILL PUSH FROM WEST TO EAST ACROSS THE
REGION TODAY. THIS WILL LOWER RH`S TO CRITICAL LEVELS FRIDAY
AFTERNOON AND COMBINE WITH GUSTY WINDS ACROSS MUCH OF CENTRAL AND
SOUTHERN NYE COUNTY TO BRING CRITICAL FIRE CONDITIONS TO THE ZONE
462. IT APPEARS THAT THIS AREA HAS RECEIVED LITTLE PRECIPITATION AND
CURRENT FUEL CONDITIONS WARRANT THE RED FLAG WARNING FOR THIS
AFTERNOON INTO THIS EVENING.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
SHORT TERM/AVIATION...WOLCOTT
LONG TERM.............PADDOCK
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
1217 AM PDT FRI AUG 7 2015
.SYNOPSIS...MONSOON MOISTURE CREEPING INTO THE AREA WILL BRING
INCREASED CHANCES FOR SHOWERS AND THUNDERSTORMS TO THE REGION
OVERNIGHT. THUNDERSTORM ACTIVITY WILL DECREASE RAPIDLY FROM WEST TO
EAST TODAY AS DRIER AIR PUSHES INTO THE REGION FOR THE WEEKEND.
ANOTHER ROUND OF MOISTURE MAY BE ON TAP FOR THE MIDDLE OF NEXT WEEK.
&&
.UPDATE...MADE SOME CHANGES TO THE POP/SKY/WX GRIDS THROUGH 12Z TO
ACCOUNT FOR THE LATEST TRENDS. A SIGNIFICANT UPTICK IN ACTIVITY HAS
BEEN NOTED OVER THE PAST 30-60 MINUTES OVER EASTERN SAN
BERNARDINO...CLARK AND SOUTHERN MOHAVE COUNTIES. HAVE RAISED POPS
AGAIN IN THOSE AREAS AS THIS ACTIVITY IS LIKELY TO PERSIST FOR AT
LEAST THE NEXT COUPLE HOURS OVER THOSE AREAS. THIS ACTIVITY HAS
DEVELOPED IN RESPONSE TO UPPER LEVEL DIVERGENCE ACTING ON A VERY
MOIST (PWATS OF 1.5-2 INCHES) AND MODERATELY UNSTABLE (MUCAPE OF 500-
1000 J/KG) ATMOSPHERE. THIS UNSTABLE AIRMASS IS EXPECTED TO CONTINUE
TO MOVE NORTHWARD THROUGH THE MORNING HOURS. FOR LAS VEGAS...THE
BEST ODDS OF SIGNIFICANT ACTIVITY REMAINS IN THE 11Z-16Z TIMEFRAME.
HOWEVER SHOWERS AND WEAK THUNDERSTORMS ARE ONGOING OVER THE VALLEY
AT THIS TIME...WHICH COULD BLUNT THE POTENTIAL BY THE TIME 11Z ROLLS
AROUND. WILL CONTINUE TO MONITOR THE SITUATION AND UPDATE AS
NECESSARY.
&&
.PREV UPDATE...1055 PM PDT THU AUG 6 2015...QUICK UPDATE TO EXPAND
POPS SOUTH TO THE SOUTHERN SAN BERNARDINO COUNTY BORDER WHERE
CONVECTION WAS STILL ONGOING AS OF 06Z. NO OTHER CHANGES AT THIS
TIME.
&&
.PREV UPDATE...956 PM PDT THU AUG 6 2015...IT`S BEEN A RELATIVELY
ACTIVE EVENING ACROSS PARTS OF THE FORECAST AREA. MOST OF THE
IMPACTFUL ACTIVITY HAS BEEN NEAR THE COLORADO RIVER NEAR THE EAST
END OF LAKE MEAD AND THE WESTERN END OF THE GRAND CANYON WHERE ONE
GAUGE HAS REPORTED 3.62 INCHES OF RAIN THUS FAR.
ADDITIONALLY...SPORADIC AND SEEMINGLY RANDOM GUSTS IN EXCESS OF 58
MPH HAVE BEEN REPORTED WITH ACTIVITY. THIS CONVECTION IS ASSOCIATED
WITH A VORTICITY LOBE THAT WILL CONTINUE TO PUSH NORTHEAST INTO UTAH
OVERNIGHT AND THUS WILL BECOME LESS OF A CONCERN OVER THE NEXT FEW
HOURS.
INSTEAD...FOCUS NOW TURNS TO THE WEST WHERE UPPER LEVEL DYNAMICS
ASSOCIATED WITH AN INCOMING CLOSED LOW WILL HELP TO TRIGGER NEW
CONVECTION FROM NOW THROUGH FRIDAY EVENING. THIS AREA IS RELATIVELY
QUIET AT THE MOMENT AS THE FORCING IS ACTING ON MOISTURE STARVED
AIR. HOWEVER AS IT PUSHES EAST AND ENCOUNTERS THE MOISTURE BOUNDARY
DRAPED ACROSS CENTRAL SAN BERNARDINO...CLARK AND LINCOLN COUNTIES IT
SHOULD BECOME MORE ACTIVE. AN ISOLATED CLUSTER OF STORMS HAS
DEVELOPED OUT AHEAD OF THIS LINE IN RIVERSIDE COUNTY AND WAS MOVING
INTO SAN BERNARDINO COUNTY AS OF 940 PM. POPS HAVE BEEN ADJUSTED TO
BETTER REFLECT THIS THINKING THROUGH FRIDAY. FOR LAS VEGAS...IT
CURRENTLY APPEARS THAT BEST ODDS FOR SHOWER/THUNDERSTORM ACTIVITY
WILL BE BETWEEN ABOUT 4AM AND 9AM AND POPS WERE ADJUSTED UP TO
REFLECT THIS. THE HRRR HAS SHOWN THIS FOR SEVERAL RUNS NOW SO
CONFIDENCE IS INCREASING. SINCE STORM MOTION WILL BE QUITE RAPID (25-
30 MPH)...FLOODING CONCERNS LIE MAINLY WITH TRAINING STORMS...WHICH
IS POSSIBLE DOWNWIND (TO THE NORTHEAST) OF TERRAIN FEATURES. THE
LARGER CONCERN WILL CONTINUE TO BE WITH DAMAGING WIND GUSTS AND TO A
LESSER EXTENT...HAIL. THE RED FLAG WARNING FOR DRY LIGHTNING WAS
CANCELLED SINCE LIGHTNING ACTIVITY HAD ENDED IN THE DRIER AREAS.
WILL CONTINUE TO MONITOR TRENDS OVERNIGHT AND UPDATE AS NECESSARY.
&&
.PREV UPDATE...431 PM PDT THU AUG 6 2015...I DID A QUICK UPDATE TO
TWEAK POPS BASED ON RADAR TRENDS WHERE WE ARE SEEING SHOWERS AND
THUNDERSTORMS. DRY LOW-LEVELS ARE RESULTING IN SPRINKLES TO VERY
LIGHT RAIN TOTALS SO FAR BUT STORMS WITH SURPRISINGLY WEAK RETURNS
ON 0.5 DEGREE RADAR REFLECTIVITY FROM BOTH KEYX AND KESX. DCAPE
VALUES ARE SHOWING A TIGHT GRADIENT OVER WESTERN CLARK AND
WESTERN/CENTRAL SAN BERNARDINO COUNTIES SO THE NORTHWEST PART OF THE
AREA WILL SEE LITTLE THREAT FOR GUSTY WINDS. HOWEVER FROM A
MERCURY/DESERT ROCK TO AMBOY TO LAKE HAVASU LINE ON EAST, GUSTS OF
30-50 MPH OR GREATER ARE POSSIBLE. THUS THE AREA OF GUSTY WINDS WAS
INCREASED IN THE WORDED FORECAST AS A THUNDERSTORM HAZARD. STORMS
SHOULD STILL TRANSITION TO A WETTER TYPE TONIGHT AS LOWER LEVEL
MOISTURE INCREASES.
&&
.PREVIOUS DISCUSSION...
ISSUED AT 205 PM PDT THU AUG 6 2015
.SHORT TERM...TODAY THROUGH FRIDAY NIGHT.
CONVECTION THUS FAR THIS AFTERNOON HAS BEEN CONFINED TO MAINLY
WESTERN SAN BERNARDINO COUNTY WHERE SOME MID LEVEL INSTABILITY IS
FUELING FAST MOVING STORMS ALONG THE LEADING EDGE OF A STRONG UPPER
LEVEL JET. SUB-CLOUD LAYERS IN THIS AREA ARE QUITE DRY WITH SURFACE
DEWPOINTS MAINLY IN THE 30S...SO GUSTY DOWNBURST WINDS ARE A CONCERN
BUT STORMS WILL STRUGGLE TO PRODUCE ANY MEASURABLE RAINFALL. WHILE
THE STORMS HAVE STRUGGLED TO DEPOSIT RAINFALL....THEY HAVE BEEN VERY
EFFICIENT LIGHTNING PRODUCERS WITH OVER 250 CLOUD TO GROUND
LIGHTNING STRIKES SINCE THE NOON HOUR IN WESTERN SAN BERNARDINO
COUNTY. WITH THIS ACTIVITY MOVING NORTHWARD...A RED FLAG WARNING HAS
BEEN POSTED FOR DRY LIGHTNING FOR MUCH OF SAN BERNARDINO COUNTY AND
THE EASTERN HALF OF INYO COUNTY THROUGH LATE TONIGHT.
STILL EXPECTING ATTENTION TO SHIFT FURTHER EAST THIS AFTERNOON AS
MORE ROBUST CONVECTION DEVELOPS ACROSS THE LOWER COLORADO RIVER
VALLEY. CURRENT MESOANALYSIS SHOWS SURFACE BASED INSTABILITY
BUILDING ACROSS THIS AREA WITH CAPE VALUES EXCEEDING 1000 J/KG WITH
LIMITED CAPPING. SEVERAL CONSECUTIVE HRRR RUNS HAVE INSISTED ON
BREAKING THIS AREA OUT IN THE NEXT FEW HOURS. THE POTENTIAL FOR
STRONG AND POTENTIALLY DAMAGING DOWNBURST WINDS IS QUITE HIGH ALONG
THE COLORADO RIVER ROUGHLY FROM BULLHEAD CITY SOUTHWARD TO LAKE
HAVASU...SO THIS AREA WILL BE WATCHED CLOSELY FOR THE POSSIBILITY OF
SEVERE STORMS.
TONIGHT...ACTIVITY ACROSS MOHAVE AND EASTERN SAN BERNARDINO COUNTIES
WILL DRIFT NORTHWARD INTO SOUTHERN NEVADA WHILE ADDITIONAL ACTIVITY
IS LIKELY TO BREAK OUT ACROSS OUR SOUTHERN GREAT BASIN ZONES. WITH
INCREASING SOUTHWESTERLY SHEAR AS A PACIFIC TROUGH APPROACHES...A
FEW BANDS OF PERSISTENT CONVECTION MAY DEVELOP OVERNIGHT WHICH WILL
BE OUR PRIMARY CONCERN FOR ANY FLASH FLOODING. INDIVIDUAL STORM
MOTION WILL BE RATHER SWIFT...BUT TRAINING STORMS WILL POSE A FLOOD
RISK WITH THE HIGH PRECIPITABLE WATER IN PLACE...SO MAINTAINED THE
FLASH FLOOD WATCH TO ACCOUNT FOR THIS FOR MOHAVE AND LINCOLN
COUNTIES. STRONG AND POTENTIALLY DAMAGING WINDS WILL REMAIN
POSSIBLE OVERNIGHT DUE TO STRENGTHENING DEEP LAYER WIND SHEAR AS
WELL AS THE POSSIBILITY OF HAIL WITH THE STRONGER STORMS.
FRIDAY...PACIFIC TROUGH WILL SWEEP EASTWARD ON FRIDAY DRAGGING THE
DEEPER MOISTURE AND INSTABILITY WITH IT. ANTICIPATE ONGOING
CONVECTION AND CLOUD COVER TO BE CONFINED MAINLY TO SOUTHERN NEVADA
AND NORTHWEST ARIZONA IN THE MORNING WHILE SHIFTING EASTWARD THROUGH
THE DAY. BY 5 PM...ANY REMAINING THUNDERSTORM ACTIVITY WILL BE
PRIMARILY CONFINED TO EASTERN MOHAVE COUNTY AND FAR EASTERN AND
NORTHERN LINCOLN COUNTIES. FLASH FLOODING WILL REMAIN A CONCERN WITH
TRAINING STORMS...BUT THE THREAT WILL BE TRANSLATING EASTWARD
THROUGH THE DAY. WITH STRONG SHEAR IN PLACE...SEVERE STORMS WILL BE
A POSSIBILITY AS WELL DEPENDING ON THE DEGREE OF CLOUD COVER AND HOW
MUCH IT INHIBITS DAYTIME HEATING. BY FRIDAY EVENING MOSTLY DRY AND
CLEAR CONDITIONS WILL OVERSPREAD THE ENTIRE REGION.
.LONG TERM...SATURDAY THROUGH THURSDAY.
A DRY SOUTHWEST FLOW WILL BE OVER THE ENTIRE FORECAST AREA SATURDAY
THROUGH MONDAY. HIGH PRESSURE OVER TEXAS WILL EXPAND WEST TOWARD NEW
MEXICO WHILE A TROUGH OF LOW PRESSURE STRETCHES GENERALLY NORTH-
SOUTH ALONG THE WEST COAST STARTING LATE MONDAY. THIS COMBINATION
WILL ALLOW SOUTHERLY FLOW TO DEVELOP WITH MOISTURE TRACKING
NORTHWARD MAINLY INTO MOHAVE COUNTY. WILL CONTINUE THE SHOWER AND
THUNDERSTORM CHANCES FOR THIS AREA TUESDAY. SOUTHERLY FLOW APPEARS
TO STICK AROUND THROUGH THURSDAY, WITH MOISTURE SLIGHTLY EDGING WEST
WEDNESDAY AND PERHAPS LINGERING INTO THURSDAY. THERE REMAINS
UNCERTAINTY IN JUST HOW MUCH MOISTURE WILL ARRIVE AND HOW FAR WEST
IT MAY TRACK. OTHERWISE NEAR NORMAL TEMPS ARE EXPECTED THROUGHOUT
THE LONG-TERM PERIOD. BREEZY SOUTH TO SOUTHWEST WINDS WILL BE COMMON
EACH AFTERNOON AND EARLY EVENING.
&&
.AVIATION...FOR MCCARRAN...OUTFLOW BOUNDARIES HAVE BEEN THE DRIVING
FACTOR FOR CONDITIONS AT MCCARRAN THIS EVENING. THIS IS EXPECTED TO
CONTINUE TO BE THE CASE THROUGH THE OVERNIGHT HOURS. AS OF THIS
WRITING...GUSTY EAST WINDS WERE MOVING INTO THE VALLEY WITH GUSTS 20-
25 KTS EXPECTED. SHOWERS CONTINUE TO DRIFT ACROSS THE REGION AND
MORE VIGOROUS THUNDERSTORMS ARE POSSIBLE DURING THE MORNING HOURS.
AT THIS TIME IT APPEARS THAT THE BEST WINDOW FOR TS WILL BE BETWEEN
11-16Z. CIGS AROUND 8K FEET...GUSTY WINDS...HEAVY RAIN WITH LOWERED
VISIBILITY...STRONG TURBULENCE AND HAIL WILL ALL BE POSSIBLE WITH
STORMS DURING THE MORNING. BY 18Z CONDITIONS SHOULD DRY OUT AND
WINDS WILL BECOME SOUTHWESTERLY AND GUSTY.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...ISOLATED TO SCATTERED THUNDERSTORMS WILL REMAIN
POSSIBLE MAINLY EAST OF A KTPH-KNXP LINE OVERNIGHT AND INTO FRIDAY
MORNING. THIS LINE WILL THEN PUSH EAST THROUGH THE DAY. CIGS AROUND
6-8K FEET...GUSTY WINDS...HEAVY RAIN WITH LOWERED VISIBILITY...
STRONG TURBULENCE AND HAIL WILL ALL BE POSSIBLE WITH STORMS DURING
THE MORNING. OUTSIDE OF THUNDERSTORM ACTIVITY EXPECT GUSTY SOUTHWEST
WINDS FRIDAY OF 15-20 KTS WITH GUSTS 25-30 KTS ACROSS MUCH OF THE
AREA.
&&
.FIRE WEATHER...AS DRIER AIR SWEEPS IN FROM THE SOUTHWEST THROUGH
FRIDAY...THIS WILL HELP TO END THE POTENTIAL FOR SHOWERS AND
THUNDERSTORMS FROM WEST TO EAST. HOWEVER...THIS WILL ALSO HELP TO
INCREASE WINDS FROM THE SOUTH TO SOUTHWEST. RELATIVE HUMIDITY VALUES
AT OR BELOW 15 PERCENT...WIND GUSTS OF 35 MPH OR GREATER AS WELL AS
FUELS BEING DRIED OUT ENOUGH LOOK TO BE MET IN NEVADA ZONE 462 AND
THE FIRE WEATHER WATCH WAS UPGRADED TO A RED FLAG WARNING HERE.
ELSEWHERE, ONLY ONE OR TWO OF THESE CRITERIA LOOK TO BE MET SO NO
HEADLINES WERE ISSUED.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
UPDATES/AVIATION/FIRE WEATHER...WOLCOTT
FIRST UPDATE...STACHELSKI
SHORT TERM...OUTLER
LONG TERM...PADDOCK
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
1055 PM PDT THU AUG 6 2015
.SYNOPSIS...MONSOON MOISTURE CREEPING INTO THE AREA WILL BRING
INCREASED CHANCES FOR SHOWERS AND THUNDERSTORMS TO THE REGION TODAY.
THUNDERSTORM ACTIVITY WILL DECREASE RAPIDLY FROM WEST TO EAST FRIDAY
AS DRIER AIR PUSHES INTO THE REGION FOR THE WEEKEND. ANOTHER ROUND
OF MOISTURE MAY BE ON TAP FOR THE MIDDLE OF NEXT WEEK.
&&
.UPDATE...QUICK UPDATE TO EXPAND POPS SOUTH TO THE SOUTHERN SAN
BERNARDINO COUNTY BORDER WHERE CONVECTION WAS STILL ONGOING AS OF
06Z. NO OTHER CHANGES AT THIS TIME.
&&
.AVIATION...FOR MCCARRAN...OUTFLOW BOUNDARIES HAVE BEEN THE DRIVING
FACTOR FOR CONDITIONS AT MCCARRAN THIS EVENING. THIS IS EXPECTED TO
CONTINUE TO BE THE CASE THROUGH THE OVERNIGHT HOURS. AS OF THIS
WRITING...GUSTY EAST WINDS WERE MOVING INTO THE VALLEY WITH GUSTS 20-
25 KTS EXPECTED. SHOWERS CONTINUE TO DRIFT ACROSS THE REGION AND
MORE VIGOROUS THUNDERSTORMS ARE POSSIBLE DURING THE MORNING HOURS.
AT THIS TIME IT APPEARS THAT THE BEST WINDOW FOR TS WILL BE BETWEEN
11-16Z. CIGS AROUND 8K FEET...GUSTY WINDS...HEAVY RAIN WITH LOWERED
VISIBILITY...STRONG TURBULENCE AND HAIL WILL ALL BE POSSIBLE WITH
STORMS DURING THE MORNING. BY 18Z CONDITIONS SHOULD DRY OUT AND
WINDS WILL BECOME SOUTHWESTERLY AND GUSTY.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...ISOLATED TO SCATTERED THUNDERSTORMS WILL REMAIN
POSSIBLE MAINLY EAST OF A KTPH-KNXP LINE OVERNIGHT AND INTO FRIDAY
MORNING. THIS LINE WILL THEN PUSH EAST THROUGH THE DAY. CIGS AROUND
6-8K FEET...GUSTY WINDS...HEAVY RAIN WITH LOWERED VISIBILITY...
STRONG TURBULENCE AND HAIL WILL ALL BE POSSIBLE WITH STORMS DURING
THE MORNING. OUTSIDE OF THUNDERSTORM ACTIVITY EXPECT GUSTY SOUTHWEST
WINDS FRIDAY OF 15-20 KTS WITH GUSTS 25-30 KTS ACROSS MUCH OF THE
AREA.
&&
.PREV UPDATE...956 PM PDT THU AUG 6 2015...IT`S BEEN A RELATIVELY
ACTIVE EVENING ACROSS PARTS OF THE FORECAST AREA. MOST OF THE
IMPACTFUL ACTIVITY HAS BEEN NEAR THE COLORADO RIVER NEAR THE EAST
END OF LAKE MEAD AND THE WESTERN END OF THE GRAND CANYON WHERE ONE
GAUGE HAS REPORTED 3.62 INCHES OF RAIN THUS FAR.
ADDITIONALLY...SPORADIC AND SEEMINGLY RANDOM GUSTS IN EXCESS OF 58
MPH HAVE BEEN REPORTED WITH ACTIVITY. THIS CONVECTION IS ASSOCIATED
WITH A VORTICITY LOBE THAT WILL CONTINUE TO PUSH NORTHEAST INTO UTAH
OVERNIGHT AND THUS WILL BECOME LESS OF A CONCERN OVER THE NEXT FEW
HOURS.
INSTEAD...FOCUS NOW TURNS TO THE WEST WHERE UPPER LEVEL DYNAMICS
ASSOCIATED WITH AN INCOMING CLOSED LOW WILL HELP TO TRIGGER NEW
CONVECTION FROM NOW THROUGH FRIDAY EVENING. THIS AREA IS RELATIVELY
QUIET AT THE MOMENT AS THE FORCING IS ACTING ON MOISTURE STARVED
AIR. HOWEVER AS IT PUSHES EAST AND ENCOUNTERS THE MOISTURE BOUNDARY
DRAPED ACROSS CENTRAL SAN BERNARDINO...CLARK AND LINCOLN COUNTIES IT
SHOULD BECOME MORE ACTIVE. AN ISOLATED CLUSTER OF STORMS HAS
DEVELOPED OUT AHEAD OF THIS LINE IN RIVERSIDE COUNTY AND WAS MOVING
INTO SAN BERNARDINO COUNTY AS OF 940 PM. POPS HAVE BEEN ADJUSTED TO
BETTER REFLECT THIS THINKING THROUGH FRIDAY. FOR LAS VEGAS...IT
CURRENTLY APPEARS THAT BEST ODDS FOR SHOWER/THUNDERSTORM ACTIVITY
WILL BE BETWEEN ABOUT 4AM AND 9AM AND POPS WERE ADJUSTED UP TO
REFLECT THIS. THE HRRR HAS SHOWN THIS FOR SEVERAL RUNS NOW SO
CONFIDENCE IS INCREASING. SINCE STORM MOTION WILL BE QUITE RAPID (25-
30 MPH)...FLOODING CONCERNS LIE MAINLY WITH TRAINING STORMS...WHICH
IS POSSIBLE DOWNWIND (TO THE NORTHEAST) OF TERRAIN FEATURES. THE
LARGER CONCERN WILL CONTINUE TO BE WITH DAMAGING WIND GUSTS AND TO A
LESSER EXTENT...HAIL. THE RED FLAG WARNING FOR DRY LIGHTNING WAS
CANCELLED SINCE LIGHTNING ACTIVITY HAD ENDED IN THE DRIER AREAS.
WILL CONTINUE TO MONITOR TRENDS OVERNIGHT AND UPDATE AS NECESSARY.
&&
.PREV UPDATE...431 PM PDT THU AUG 6 2015...I DID A QUICK UPDATE TO
TWEAK POPS BASED ON RADAR TRENDS WHERE WE ARE SEEING SHOWERS AND
THUNDERSTORMS. DRY LOW-LEVELS ARE RESULTING IN SPRINKLES TO VERY
LIGHT RAIN TOTALS SO FAR BUT STORMS WITH SURPRISINGLY WEAK RETURNS
ON 0.5 DEGREE RADAR REFLECTIVITY FROM BOTH KEYX AND KESX. DCAPE
VALUES ARE SHOWING A TIGHT GRADIENT OVER WESTERN CLARK AND
WESTERN/CENTRAL SAN BERNARDINO COUNTIES SO THE NORTHWEST PART OF THE
AREA WILL SEE LITTLE THREAT FOR GUSTY WINDS. HOWEVER FROM A
MERCURY/DESERT ROCK TO AMBOY TO LAKE HAVASU LINE ON EAST, GUSTS OF
30-50 MPH OR GREATER ARE POSSIBLE. THUS THE AREA OF GUSTY WINDS WAS
INCREASED IN THE WORDED FORECAST AS A THUNDERSTORM HAZARD. STORMS
SHOULD STILL TRANSITION TO A WETTER TYPE TONIGHT AS LOWER LEVEL
MOISTURE INCREASES.
&&
.PREVIOUS DISCUSSION...
ISSUED AT 205 PM PDT THU AUG 6 2015
.SHORT TERM...TODAY THROUGH FRIDAY NIGHT.
CONVECTION THUS FAR THIS AFTERNOON HAS BEEN CONFINED TO MAINLY
WESTERN SAN BERNARDINO COUNTY WHERE SOME MID LEVEL INSTABILITY IS
FUELING FAST MOVING STORMS ALONG THE LEADING EDGE OF A STRONG UPPER
LEVEL JET. SUB-CLOUD LAYERS IN THIS AREA ARE QUITE DRY WITH SURFACE
DEWPOINTS MAINLY IN THE 30S...SO GUSTY DOWNBURST WINDS ARE A CONCERN
BUT STORMS WILL STRUGGLE TO PRODUCE ANY MEASURABLE RAINFALL. WHILE
THE STORMS HAVE STRUGGLED TO DEPOSIT RAINFALL....THEY HAVE BEEN VERY
EFFICIENT LIGHTNING PRODUCERS WITH OVER 250 CLOUD TO GROUND
LIGHTNING STRIKES SINCE THE NOON HOUR IN WESTERN SAN BERNARDINO
COUNTY. WITH THIS ACTIVITY MOVING NORTHWARD...A RED FLAG WARNING HAS
BEEN POSTED FOR DRY LIGHTNING FOR MUCH OF SAN BERNARDINO COUNTY AND
THE EASTERN HALF OF INYO COUNTY THROUGH LATE TONIGHT.
STILL EXPECTING ATTENTION TO SHIFT FURTHER EAST THIS AFTERNOON AS
MORE ROBUST CONVECTION DEVELOPS ACROSS THE LOWER COLORADO RIVER
VALLEY. CURRENT MESOANALYSIS SHOWS SURFACE BASED INSTABILITY
BUILDING ACROSS THIS AREA WITH CAPE VALUES EXCEEDING 1000 J/KG WITH
LIMITED CAPPING. SEVERAL CONSECUTIVE HRRR RUNS HAVE INSISTED ON
BREAKING THIS AREA OUT IN THE NEXT FEW HOURS. THE POTENTIAL FOR
STRONG AND POTENTIALLY DAMAGING DOWNBURST WINDS IS QUITE HIGH ALONG
THE COLORADO RIVER ROUGHLY FROM BULLHEAD CITY SOUTHWARD TO LAKE
HAVASU...SO THIS AREA WILL BE WATCHED CLOSELY FOR THE POSSIBILITY OF
SEVERE STORMS.
TONIGHT...ACTIVITY ACROSS MOHAVE AND EASTERN SAN BERNARDINO COUNTIES
WILL DRIFT NORTHWARD INTO SOUTHERN NEVADA WHILE ADDITIONAL ACTIVITY
IS LIKELY TO BREAK OUT ACROSS OUR SOUTHERN GREAT BASIN ZONES. WITH
INCREASING SOUTHWESTERLY SHEAR AS A PACIFIC TROUGH APPROACHES...A
FEW BANDS OF PERSISTENT CONVECTION MAY DEVELOP OVERNIGHT WHICH WILL
BE OUR PRIMARY CONCERN FOR ANY FLASH FLOODING. INDIVIDUAL STORM
MOTION WILL BE RATHER SWIFT...BUT TRAINING STORMS WILL POSE A FLOOD
RISK WITH THE HIGH PRECIPITABLE WATER IN PLACE...SO MAINTAINED THE
FLASH FLOOD WATCH TO ACCOUNT FOR THIS FOR MOHAVE AND LINCOLN
COUNTIES. STRONG AND POTENTIALLY DAMAGING WINDS WILL REMAIN
POSSIBLE OVERNIGHT DUE TO STRENGTHENING DEEP LAYER WIND SHEAR AS
WELL AS THE POSSIBILITY OF HAIL WITH THE STRONGER STORMS.
FRIDAY...PACIFIC TROUGH WILL SWEEP EASTWARD ON FRIDAY DRAGGING THE
DEEPER MOISTURE AND INSTABILITY WITH IT. ANTICIPATE ONGOING
CONVECTION AND CLOUD COVER TO BE CONFINED MAINLY TO SOUTHERN NEVADA
AND NORTHWEST ARIZONA IN THE MORNING WHILE SHIFTING EASTWARD THROUGH
THE DAY. BY 5 PM...ANY REMAINING THUNDERSTORM ACTIVITY WILL BE
PRIMARILY CONFINED TO EASTERN MOHAVE COUNTY AND FAR EASTERN AND
NORTHERN LINCOLN COUNTIES. FLASH FLOODING WILL REMAIN A CONCERN WITH
TRAINING STORMS...BUT THE THREAT WILL BE TRANSLATING EASTWARD
THROUGH THE DAY. WITH STRONG SHEAR IN PLACE...SEVERE STORMS WILL BE
A POSSIBILITY AS WELL DEPENDING ON THE DEGREE OF CLOUD COVER AND HOW
MUCH IT INHIBITS DAYTIME HEATING. BY FRIDAY EVENING MOSTLY DRY AND
CLEAR CONDITIONS WILL OVERSPREAD THE ENTIRE REGION.
.LONG TERM...SATURDAY THROUGH THURSDAY.
A DRY SOUTHWEST FLOW WILL BE OVER THE ENTIRE FORECAST AREA SATURDAY
THROUGH MONDAY. HIGH PRESSURE OVER TEXAS WILL EXPAND WEST TOWARD NEW
MEXICO WHILE A TROUGH OF LOW PRESSURE STRETCHES GENERALLY NORTH-
SOUTH ALONG THE WEST COAST STARTING LATE MONDAY. THIS COMBINATION
WILL ALLOW SOUTHERLY FLOW TO DEVELOP WITH MOISTURE TRACKING
NORTHWARD MAINLY INTO MOHAVE COUNTY. WILL CONTINUE THE SHOWER AND
THUNDERSTORM CHANCES FOR THIS AREA TUESDAY. SOUTHERLY FLOW APPEARS
TO STICK AROUND THROUGH THURSDAY, WITH MOISTURE SLIGHTLY EDGING WEST
WEDNESDAY AND PERHAPS LINGERING INTO THURSDAY. THERE REMAINS
UNCERTAINTY IN JUST HOW MUCH MOISTURE WILL ARRIVE AND HOW FAR WEST
IT MAY TRACK. OTHERWISE NEAR NORMAL TEMPS ARE EXPECTED THROUGHOUT
THE LONG-TERM PERIOD. BREEZY SOUTH TO SOUTHWEST WINDS WILL BE COMMON
EACH AFTERNOON AND EARLY EVENING.
&&
.FIRE WEATHER...AS DRIER AIR SWEEPS IN FROM THE SOUTHWEST THROUGH
FRIDAY...THIS WILL HELP TO END THE POTENTIAL FOR SHOWERS AND
THUNDERSTORMS FROM WEST TO EAST. HOWEVER...THIS WILL ALSO HELP TO
INCREASE WINDS FROM THE SOUTH TO SOUTHWEST. RELATIVE HUMIDITY VALUES
AT OR BELOW 15 PERCENT...WIND GUSTS OF 35 MPH OR GREATER AS WELL AS
FUELS BEING DRIED OUT ENOUGH LOOK TO BE MET IN NEVADA ZONE 462 AND
THE FIRE WEATHER WATCH WAS UPGRADED TO A RED FLAG WARNING HERE.
ELSEWHERE, ONLY ONE OR TWO OF THESE CRITERIA LOOK TO BE MET SO NO
HEADLINES WERE ISSUED.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
UPDATE/AVIATION/FIRE WEATHER...WOLCOTT
PREV UPDATE...STACHELSKI
SHORT TERM...OUTLER
LONG TERM...PADDOCK
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
956 PM PDT THU AUG 6 2015
.SYNOPSIS...MONSOON MOISTURE CREEPING INTO THE AREA WILL BRING
INCREASED CHANCES FOR SHOWERS AND THUNDERSTORMS TO THE REGION TODAY.
THUNDERSTORM ACTIVITY WILL DECREASE RAPIDLY FROM WEST TO EAST FRIDAY
AS DRIER AIR PUSHES INTO THE REGION FOR THE WEEKEND. ANOTHER ROUND
OF MOISTURE MAY BE ON TAP FOR THE MIDDLE OF NEXT WEEK.
&&
.UPDATE...IT`S BEEN A RELATIVELY ACTIVE EVENING ACROSS PARTS OF THE
FORECAST AREA. MOST OF THE IMPACTFUL ACTIVITY HAS BEEN NEAR THE
COLORADO RIVER NEAR THE EAST END OF LAKE MEAD AND THE WESTERN END OF
THE GRAND CANYON WHERE ONE GAUGE HAS REPORTED 3.62 INCHES OF RAIN
THUS FAR. ADDITIONALLY...SPORADIC AND SEEMINGLY RANDOM GUSTS IN
EXCESS OF 58 MPH HAVE BEEN REPORTED WITH ACTIVITY. THIS CONVECTION
IS ASSOCIATED WITH A VORTICITY LOBE THAT WILL CONTINUE TO PUSH
NORTHEAST INTO UTAH OVERNIGHT AND THUS WILL BECOME LESS OF A CONCERN
OVER THE NEXT FEW HOURS.
INSTEAD...FOCUS NOW TURNS TO THE WEST WHERE UPPER LEVEL DYNAMICS
ASSOCIATED WITH AN INCOMING CLOSED LOW WILL HELP TO TRIGGER NEW
CONVECTION FROM NOW THROUGH FRIDAY EVENING. THIS AREA IS RELATIVELY
QUIET AT THE MOMENT AS THE FORCING IS ACTING ON MOISTURE STARVED
AIR. HOWEVER AS IT PUSHES EAST AND ENCOUNTERS THE MOISTURE BOUNDARY
DRAPED ACROSS CENTRAL SAN BERNARDINO...CLARK AND LINCOLN COUNTIES IT
SHOULD BECOME MORE ACTIVE. AN ISOLATED CLUSTER OF STORMS HAS
DEVELOPED OUT AHEAD OF THIS LINE IN RIVERSIDE COUNTY AND WAS MOVING
INTO SAN BERNARDINO COUNTY AS OF 940 PM. POPS HAVE BEEN ADJUSTED TO
BETTER REFLECT THIS THINKING THROUGH FRIDAY. FOR LAS VEGAS...IT
CURRENTLY APPEARS THAT BEST ODDS FOR SHOWER/THUNDERSTORM ACTIVITY
WILL BE BETWEEN ABOUT 4AM AND 9AM AND POPS WERE ADJUSTED UP TO
REFLECT THIS. THE HRRR HAS SHOWN THIS FOR SEVERAL RUNS NOW SO
CONFIDENCE IS INCREASING. SINCE STORM MOTION WILL BE QUITE RAPID (25-
30 MPH)...FLOODING CONCERNS LIE MAINLY WITH TRAINING STORMS...WHICH
IS POSSIBLE DOWNWIND (TO THE NORTHEAST) OF TERRAIN FEATURES. THE
LARGER CONCERN WILL CONTINUE TO BE WITH DAMAGING WIND GUSTS AND TO A
LESSER EXTENT...HAIL. THE RED FLAG WARNING FOR DRY LIGHTNING WAS
CANCELLED SINCE LIGHTNING ACTIVITY HAD ENDED IN THE DRIER AREAS.
WILL CONTINUE TO MONITOR TRENDS OVERNIGHT AND UPDATE AS NECESSARY.
&&
.AVIATION...FOR MCCARRAN...OUTFLOW BOUNDARIES HAVE BEEN THE DRIVING
FACTOR FOR CONDITIONS AT MCCARRAN THIS EVENING. THIS IS EXPECTED TO
CONTINUE TO BE THE CASE THROUGH THE OVERNIGHT HOURS. AS OF THIS
WRITING...GUSTY EAST WINDS WERE MOVING INTO THE VALLEY WITH GUSTS 20-
25 KTS EXPECTED. SHOWERS CONTINUE TO DRIFT ACROSS THE REGION AND
MORE VIGOROUS THUNDERSTORMS ARE POSSIBLE DURING THE MORNING HOURS.
AT THIS TIME IT APPEARS THAT THE BEST WINDOW FOR TS WILL BE BETWEEN
11-16Z. CIGS AROUND 8K FEET...GUSTY WINDS...HEAVY RAIN WITH LOWERED
VISIBILITY...STRONG TURBULENCE AND HAIL WILL ALL BE POSSIBLE WITH
STORMS DURING THE MORNING. BY 18Z CONDITIONS SHOULD DRY OUT AND
WINDS WILL BECOME SOUTHWESTERLY AND GUSTY.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...ISOLATED TO SCATTERED THUNDERSTORMS WILL REMAIN
POSSIBLE MAINLY EAST OF A KTPH-KNXP LINE OVERNIGHT AND INTO FRIDAY
MORNING. THIS LINE WILL THEN PUSH EAST THROUGH THE DAY. CIGS AROUND
6-8K FEET...GUSTY WINDS...HEAVY RAIN WITH LOWERED VISIBILITY...
STRONG TURBULENCE AND HAIL WILL ALL BE POSSIBLE WITH STORMS DURING
THE MORNING. OUTSIDE OF THUNDERSTORM ACTIVITY EXPECT GUSTY SOUTHWEST
WINDS FRIDAY OF 15-20 KTS WITH GUSTS 25-30 KTS ACROSS MUCH OF THE
AREA.
&&
.PREV UPDATE...431 PM PDT THU AUG 6 2015...I DID A QUICK UPDATE TO
TWEAK POPS BASED ON RADAR TRENDS WHERE WE ARE SEEING SHOWERS AND
THUNDERSTORMS. DRY LOW-LEVELS ARE RESULTING IN SPRINKLES TO VERY
LIGHT RAIN TOTALS SO FAR BUT STORMS WITH SURPRISINGLY WEAK RETURNS
ON 0.5 DEGREE RADAR REFLECTIVITY FROM BOTH KEYX AND KESX. DCAPE
VALUES ARE SHOWING A TIGHT GRADIENT OVER WESTERN CLARK AND
WESTERN/CENTRAL SAN BERNARDINO COUNTIES SO THE NORTHWEST PART OF THE
AREA WILL SEE LITTLE THREAT FOR GUSTY WINDS. HOWEVER FROM A
MERCURY/DESERT ROCK TO AMBOY TO LAKE HAVASU LINE ON EAST, GUSTS OF
30-50 MPH OR GREATER ARE POSSIBLE. THUS THE AREA OF GUSTY WINDS WAS
INCREASED IN THE WORDED FORECAST AS A THUNDERSTORM HAZARD. STORMS
SHOULD STILL TRANSITION TO A WETTER TYPE TONIGHT AS LOWER LEVEL
MOISTURE INCREASES.
&&
.PREVIOUS DISCUSSION...
ISSUED AT 205 PM PDT THU AUG 6 2015
.SHORT TERM...TODAY THROUGH FRIDAY NIGHT.
CONVECTION THUS FAR THIS AFTERNOON HAS BEEN CONFINED TO MAINLY
WESTERN SAN BERNARDINO COUNTY WHERE SOME MID LEVEL INSTABILITY IS
FUELING FAST MOVING STORMS ALONG THE LEADING EDGE OF A STRONG UPPER
LEVEL JET. SUB-CLOUD LAYERS IN THIS AREA ARE QUITE DRY WITH SURFACE
DEWPOINTS MAINLY IN THE 30S...SO GUSTY DOWNBURST WINDS ARE A CONCERN
BUT STORMS WILL STRUGGLE TO PRODUCE ANY MEASURABLE RAINFALL. WHILE
THE STORMS HAVE STRUGGLED TO DEPOSIT RAINFALL....THEY HAVE BEEN VERY
EFFICIENT LIGHTNING PRODUCERS WITH OVER 250 CLOUD TO GROUND
LIGHTNING STRIKES SINCE THE NOON HOUR IN WESTERN SAN BERNARDINO
COUNTY. WITH THIS ACTIVITY MOVING NORTHWARD...A RED FLAG WARNING HAS
BEEN POSTED FOR DRY LIGHTNING FOR MUCH OF SAN BERNARDINO COUNTY AND
THE EASTERN HALF OF INYO COUNTY THROUGH LATE TONIGHT.
STILL EXPECTING ATTENTION TO SHIFT FURTHER EAST THIS AFTERNOON AS
MORE ROBUST CONVECTION DEVELOPS ACROSS THE LOWER COLORADO RIVER
VALLEY. CURRENT MESOANALYSIS SHOWS SURFACE BASED INSTABILITY
BUILDING ACROSS THIS AREA WITH CAPE VALUES EXCEEDING 1000 J/KG WITH
LIMITED CAPPING. SEVERAL CONSECUTIVE HRRR RUNS HAVE INSISTED ON
BREAKING THIS AREA OUT IN THE NEXT FEW HOURS. THE POTENTIAL FOR
STRONG AND POTENTIALLY DAMAGING DOWNBURST WINDS IS QUITE HIGH ALONG
THE COLORADO RIVER ROUGHLY FROM BULLHEAD CITY SOUTHWARD TO LAKE
HAVASU...SO THIS AREA WILL BE WATCHED CLOSELY FOR THE POSSIBILITY OF
SEVERE STORMS.
TONIGHT...ACTIVITY ACROSS MOHAVE AND EASTERN SAN BERNARDINO COUNTIES
WILL DRIFT NORTHWARD INTO SOUTHERN NEVADA WHILE ADDITIONAL ACTIVITY
IS LIKELY TO BREAK OUT ACROSS OUR SOUTHERN GREAT BASIN ZONES. WITH
INCREASING SOUTHWESTERLY SHEAR AS A PACIFIC TROUGH APPROACHES...A
FEW BANDS OF PERSISTENT CONVECTION MAY DEVELOP OVERNIGHT WHICH WILL
BE OUR PRIMARY CONCERN FOR ANY FLASH FLOODING. INDIVIDUAL STORM
MOTION WILL BE RATHER SWIFT...BUT TRAINING STORMS WILL POSE A FLOOD
RISK WITH THE HIGH PRECIPITABLE WATER IN PLACE...SO MAINTAINED THE
FLASH FLOOD WATCH TO ACCOUNT FOR THIS FOR MOHAVE AND LINCOLN
COUNTIES. STRONG AND POTENTIALLY DAMAGING WINDS WILL REMAIN
POSSIBLE OVERNIGHT DUE TO STRENGTHENING DEEP LAYER WIND SHEAR AS
WELL AS THE POSSIBILITY OF HAIL WITH THE STRONGER STORMS.
FRIDAY...PACIFIC TROUGH WILL SWEEP EASTWARD ON FRIDAY DRAGGING THE
DEEPER MOISTURE AND INSTABILITY WITH IT. ANTICIPATE ONGOING
CONVECTION AND CLOUD COVER TO BE CONFINED MAINLY TO SOUTHERN NEVADA
AND NORTHWEST ARIZONA IN THE MORNING WHILE SHIFTING EASTWARD THROUGH
THE DAY. BY 5 PM...ANY REMAINING THUNDERSTORM ACTIVITY WILL BE
PRIMARILY CONFINED TO EASTERN MOHAVE COUNTY AND FAR EASTERN AND
NORTHERN LINCOLN COUNTIES. FLASH FLOODING WILL REMAIN A CONCERN WITH
TRAINING STORMS...BUT THE THREAT WILL BE TRANSLATING EASTWARD
THROUGH THE DAY. WITH STRONG SHEAR IN PLACE...SEVERE STORMS WILL BE
A POSSIBILITY AS WELL DEPENDING ON THE DEGREE OF CLOUD COVER AND HOW
MUCH IT INHIBITS DAYTIME HEATING. BY FRIDAY EVENING MOSTLY DRY AND
CLEAR CONDITIONS WILL OVERSPREAD THE ENTIRE REGION.
.LONG TERM...SATURDAY THROUGH THURSDAY.
A DRY SOUTHWEST FLOW WILL BE OVER THE ENTIRE FORECAST AREA SATURDAY
THROUGH MONDAY. HIGH PRESSURE OVER TEXAS WILL EXPAND WEST TOWARD NEW
MEXICO WHILE A TROUGH OF LOW PRESSURE STRETCHES GENERALLY NORTH-
SOUTH ALONG THE WEST COAST STARTING LATE MONDAY. THIS COMBINATION
WILL ALLOW SOUTHERLY FLOW TO DEVELOP WITH MOISTURE TRACKING
NORTHWARD MAINLY INTO MOHAVE COUNTY. WILL CONTINUE THE SHOWER AND
THUNDERSTORM CHANCES FOR THIS AREA TUESDAY. SOUTHERLY FLOW APPEARS
TO STICK AROUND THROUGH THURSDAY, WITH MOISTURE SLIGHTLY EDGING WEST
WEDNESDAY AND PERHAPS LINGERING INTO THURSDAY. THERE REMAINS
UNCERTAINTY IN JUST HOW MUCH MOISTURE WILL ARRIVE AND HOW FAR WEST
IT MAY TRACK. OTHERWISE NEAR NORMAL TEMPS ARE EXPECTED THROUGHOUT
THE LONG-TERM PERIOD. BREEZY SOUTH TO SOUTHWEST WINDS WILL BE COMMON
EACH AFTERNOON AND EARLY EVENING.
&&
.FIRE WEATHER...AS DRIER AIR SWEEPS IN FROM THE SOUTHWEST THROUGH
FRIDAY...THIS WILL HELP TO END THE POTENTIAL FOR SHOWERS AND
THUNDERSTORMS FROM WEST TO EAST. HOWEVER...THIS WILL ALSO HELP TO
INCREASE WINDS FROM THE SOUTH TO SOUTHWEST. RELATIVE HUMIDITY VALUES
AT OR BELOW 15 PERCENT...WIND GUSTS OF 35 MPH OR GREATER AS WELL AS
FUELS BEING DRIED OUT ENOUGH LOOK TO BE MET IN NEVADA ZONE 462 AND
THE FIRE WEATHER WATCH WAS UPGRADED TO A RED FLAG WARNING HERE.
ELSEWHERE, ONLY ONE OR TWO OF THESE CRITERIA LOOK TO BE MET SO NO
HEADLINES WERE ISSUED.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
UPDATE/AVIATION/FIRE WEATHER...WOLCOTT
PREV UPDATE...STACHELSKI
SHORT TERM...OUTLER
LONG TERM...PADDOCK
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION...UPDATED
NWS WILMINGTON NC
434 PM EDT FRI AUG 7 2015
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS WILL PRECEDE AN APPROACHING COLD FRONT
THROUGH THIS EVENING. THE FRONT WILL CROSS THE COAST VERY EARLY
ON SATURDAY...USHERING DRIER AND COOLER CONDITIONS THIS WEEKEND
INTO EARLY NEXT WEEK. RAIN CHANCES WILL INCREASE TUESDAY INTO
THE MIDDLE OF NEXT WEEK...AS A FRONT STALLS ALONG OUR COAST.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 430 PM FRIDAY...QUICK FORECAST UPDATE MAINLY TO ALIGN THE
FORECAST TO EXTRAPOLATED RADAR TRENDS. THE LOW IS CENTERED NEAR
THE PENDER/BLADEN COUNTY LINE AND MOVING EASTWARD...PUSHING THE
MAIN CONVECTIVE LINE ACROSS THE WILMINGTON AREA AT THIS TIME.
BEHIND THIS FEATURE LIGHTER SHOWERS WILL PERSIST THROUGH SUNSET.
ALTHOUGH I WOULD LIKE TO END THE POTENTIAL FOR SHOWERS AT THAT
TIME...MODELS ARE QUITE INSISTENT THAT SOME WRAPAROUND CLOUDS AND
LIGHT PRECIP MAY CONTINUE OVERNIGHT...PARTICULARLY ACROSS SE NORTH
CAROLINA. DISCUSSION FROM 222 PM FOLLOWS...
SURFACE ANALYSIS PLACED THE FRONTAL BOUNDARY ALONG A LINE FROM
NEAR KINGSTREE TO ELIZABETHTOWN. LATEST HRRR GUIDANCE INDICATES
THE BOUNDARY WILL SLOW LATE THIS AFTERNOON AS IT NEARS THE COAST
BUT WILL PUSH OFFSHORE AFTER 00Z. CONVECTION WILL DIMINISH WITH
THE LOSS OF DAYTIME HEATING AND WITH INFILTRATION OF DRIER AIR
EVIDENT IN WATER VAPOR IMAGERY. WILL HANG ON TO CHANCE POPS FOR
THE COASTAL COUNTIES OF SOUTHEASTERN NC FOR A FEW HOURS AFTER
SUNSET AS A FEW LINGERING SHOWERS MAY WRAP AROUND THE DEPARTING
SURFACE LOW.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
AS OF 222 PM FRIDAY...CENTRAL WEEKEND HEADLINE REMAINS ADVANCEMENT
OF AN AIR MASS CHANGE INTO THE REGION...OFFERING COOLER AND DRIER
HOURLY...MAXIMUM...MINIMUM TEMPERATURES BOTH SATURDAY AND SUNDAY.
DAYBREAK SATURDAY A SURFACE LOW WILL BECOME POSITIONED ROUGHLY 125
MILES ENE OF CAPE FEAR...RESULTING IN A SURFACE FRONT ACROSS THE
OUTER WATER...AND OFFSHORE N-NNW WINDS OVER OUR LAND ZONES. THIS
MARKS THE ONSET OF DEWPOINT DROPS THROUGHOUT MOST OF THE WEEKEND
MAKING FOR A VERY COMFORTABLE FEEL. A FEW SHOWERS MAY WRAP ON THE
BACK SIDE OF THE SURFACE LOW NEAR CAPE FEAR EARLY SATURDAY BUT A
DRYING TREND WILL PREVAIL THROUGH THE DAY.
MAXIMUMS SATURDAY 85-90...WARMEST WELL INLAND...AND 2-3 DEGREES
F WARMER SUNDAY ON MAXIMUMS. THE DRIER AIR MASS UNDER MOSTLY
CLEAR CONDITIONS WILL ALLOW OVERNIGHT TEMPERATURES TO DIP INTO
THE 60S SUNRISE SUNDAY OVER MOST AREAS...AROUND 70 SC INTERIOR.
A DEGREE OR 2 MILDER MONDAY MORNING BUT STILL PLEASANTLY VOID
OF HIGH HUMIDITY.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 222 PM FRIDAY...THE MID LEVEL RIDGE THAT HAS BEEN SITTING
OVER TEXAS FOR SOME TIME STARTS OUT THE PERIOD WITH AN EXTENSION
ACROSS THE SOUTHEAST. THE RIDGE GETS PUSHED BACK TO THE WEST AS A
STRONG SHORTWAVE MOVES ACROSS THE MIDWEST. THIS WILL LEAD TO
UNUSUALLY STRONG TROUGHING ACROSS THE SOUTHEAST THROUGH THE END OF
THE PERIOD. AT THE SURFACE HIGH PRESSURE MONDAY WILL GIVE WAY TO A
DECENT COLD FRONT ASSOCIATED WITH THE TROUGH THAT MOVES ACROSS
LATE TUESDAY AND WEDNESDAY. WE CONTINUE WITH GOOD POPS TUESDAY
LINGERING INTO WEDNESDAY. THURSDAY AND FRIDAY SHOULD SEE A DRYING
TREND. TEMPERATURES ARE A LITTLE ON THE WARM SIDE EARLY...DROPPING
TO SEASONAL NORMALS BY MID AND LATE WEEK.
&&
.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
AS OF 18Z...DYNAMIC CONDITIONS WITH DEEP MOISTURE IN PLACE. LOOK
FOR SCT SHRA AND ISOLD TSTMS TO FIRE AT ANY TIME TODAY AND
CONCENTRATED IN THE EASTERN PORTION OF THE CWA. CEILINGS AND VIS
WILL VARY FROM VFR TO POTENTIALLY LIFR IN THE HEAVIEST
ACTIVITY...BUT PREDOMINATELY MVFR. THE PRESSURE GRADIENT WILL BE
FAIRLY STRONG TODAY...WITH GUSTS OVER 20 KTS EXPECTED...STRONGER
IN CONVECTION. MOST OF THE ACTIVITY WILL END BY 00Z...WITH
ISOLATED ACTIVITY OVERNIGHT. WINDS SWING TO THE NORTH THIS EVENING
AS SURFACE LOW MOVES BY TO THE NORTHEAST. POST FRONTAL STRATUS IS
GOOD BET OVERNIGHT. SATURDAY...SLOWLY IMPROVING CONDITIONS BUT
STILL A CHANCE FOR PRECIP ALONG THE COAST.
EXTENDED OUTLOOK...PREDOMINATELY VFR SUNDAY. STORMS AGAIN MONDAY AND
TUESDAY...WITH PERIODS OF MVFR POSSIBLE. VFR WEDNESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 430 PM FRIDAY...QUICK FORECAST UPDATE TO ADJUST SHOWER AND
THUNDERSTORM CHANCES AND TIMING BASED ON RADAR TRENDS. ALSO
BUMPED UP WINDS JUST A TOUCH AHEAD OF THE CONVECTIVE LINE WHERE
THE SOUTHERLY JET AHEAD OF THE WEAK LOW NW OF WILMINGTON HAS
PRODUCED SUSTAINED WIND SPEEDS NEAR 15 KNOTS FROM FRYING PAN
SHOALS BUOY UP TO WRIGHTSVILLE BEACH. DISCUSSION FROM 222 PM
FOLLOWS...
THE COLD FRONT WAS POSITIONED NEAR A KINGSTREE TO ELIZABETHTOWN
LINE EARLY THIS AFTERNOON...AND WILL MOVE OFFSHORE AND ACROSS THE
COASTAL WATERS DURING THE EARLY EVENING HOURS. THE PRESSURE
GRADIENT ALONG AND BEHIND THE FRONT IS RELATIVELY WEAK SO EXPECT
NO ADVISORIES WILL BE REQUIRED. THE POTENTIAL FOR SCATTERED
SHOWERS AND A FEW THUNDERSTORMS WILL CONTINUE UNTIL THE FRONT
CLEARS THE COASTAL WATERS AROUND MIDNIGHT.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 222 PM FRIDAY...MAIN MARINE HEADLINE REMAINS THE PREVAILING
NORTH WIND MUCH OF THE WEEKEND IN WAKE OF A COLD FRONT AND LOW
PRESSURE SYSTEM LINGERING OVER THE OFFSHORE WATERS SATURDAY AND
SUNDAY. BECAUSE OF THE WIND TRAJECTORY...TAMEST SEA CONDITIONS
WILL RESIDE NEAR SHORE...WHEREAS FARTHER OUT AS THE FETCH LENGTH
INCREASES...SEAS WILL BECOME INCREASINGLY BUMPY IN WIND-DEVELOPED
CHOP. WINDSPEEDS WILL BEGIN TO DECREASE THROUGH SUNDAY AS THE
SURFACE LOW PULLS FARTHER EAST TO SEA AND THE LOCAL PRESSURE
GRADIENT LOOSENS-UP. BY SUNDAY NIGHT OR EARLY MONDAY WINDS WILL
SWING AROUND TO THE S-SE LIGHTLY. SLIGHTLY BUMPY SATURDAY IN THE
EARLY GOING AS RESIDUAL SSW WAVES 3-4 FT EVERY 6 SEC INTERACT
WITH NNW WIND CHOP MAKING FOR A PITCHY SPECTRUM. A FEW TSTMS MAY
IMPACT THE OFFSHORE WATERS SATURDAY...MAINLY GULF STREAM WATERS.
LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 222 PM FRIDAY...LIGHT WINDS SHOULD PREVAIL OVER THE WATERS
MONDAY UNDER A WEAK PRESSURE GRADIENT. BY TUESDAY A DECENT SOUTHWEST
FLOW SETS UP AHEAD OF A COLD FRONT MOVING ACROSS THE APPALACHIANS.
THE FRONT WILL VERY SLOWLY MOVE ACROSS THE WATERS AND IN FACT...THIS
WILL OCCUR JUST AFTER THE END OF THIS FORECAST PERIOD. WITH THE
SOUTHWEST FLOW OF 15-20 KNOTS TUESDAY...SEAS COULD INCREASE TO 3-5
FEET FOR SOME TIME OTHERWISE THE STANDARD 2-4 FEET SHOULD SUFFICE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...TRA/CRM
SHORT TERM...MJC
LONG TERM...SHK
AVIATION...DL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
222 PM EDT FRI AUG 7 2015
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS WILL PRECEDE AN APPROACHING COLD FRONT
THROUGH THIS EVENING. THE FRONT WILL CROSS THE COAST VERY EARLY
ON SATURDAY...USHERING DRIER AND COOLER CONDITIONS THIS WEEKEND
INTO EARLY NEXT WEEK. RAIN CHANCES WILL INCREASE TUESDAY INTO
THE MIDDLE OF NEXT WEEK...AS A FRONT STALLS ALONG OUR COAST.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 222 PM FRIDAY...AS OF THIS AFTERNOON...SURFACE ANALYSIS
PLACED THE FRONTAL BOUNDARY ALONG A LINE FROM NEAR KINGSTREE TO
ELIZABETHTOWN. LATEST HRRR GUIDANCE INDICATES THE BOUNDARY WILL
SLOW LATE THIS AFTERNOON AS IT NEARS THE COAST BUT WILL PUSH
OFFSHORE AFTER 00Z. CONVECTION WILL DIMINISH WITH THE LOSS OF
DAYTIME HEATING AND WITH INFILTRATION OF DRIER AIR EVIDENT IN
WATER VAPOR IMAGERY. WILL HANG ON TO CHANCE POPS FOR THE COASTAL
COUNTIES OF SOUTHEASTERN NC FOR A FEW HOURS AFTER SUNSET AS A FEW
LINGERING SHOWERS MAY WRAP AROUND THE DEPARTING SURFACE LOW.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 222 PM FRIDAY...CENTRAL WEEKEND HEADLINE REMAINS ADVANCEMENT
OF AN AIR MASS CHANGE INTO THE REGION...OFFERING COOLER AND DRIER
HOURLY...MAXIMUM...MINIMUM TEMPERATURES BOTH SATURDAY AND SUNDAY.
DAYBREAK SATURDAY A SURFACE LOW WILL BECOME POSITIONED ROUGHLY 125
MILES ENE OF CAPE FEAR...RESULTING IN A SURFACE FRONT ACROSS THE
OUTER WATER...AND OFFSHORE N-NNW WINDS OVER OUR LAND ZONES. THIS
MARKS THE ONSET OF DEWPOINT DROPS THROUGHOUT MOST OF THE WEEKEND
MAKING FOR A VERY COMFORTABLE FEEL. A FEW SHOWERS MAY WRAP ON THE
BACK SIDE OF THE SURFACE LOW NEAR CAPE FEAR EARLY SATURDAY BUT A
DRYING TREND WILL PREVAIL THROUGH THE DAY.
MAXIMUMS SATURDAY 85-90...WARMEST WELL INLAND...AND 2-3 DEGREES
F WARMER SUNDAY ON MAXIMUMS. THE DRIER AIR MASS UNDER MOSTLY
CLEAR CONDITIONS WILL ALLOW OVERNIGHT TEMPERATURES TO DIP INTO
THE 60S SUNRISE SUNDAY OVER MOST AREAS...AROUND 70 SC INTERIOR.
A DEGREE OR 2 MILDER MONDAY MORNING BUT STILL PLEASANTLY VOID
OF HIGH HUMIDITY.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 222 PM FRIDAY...THE MID LEVEL RIDGE THAT HAS BEEN SITTING
OVER TEXAS FOR SOME TIME STARTS OUT THE PERIOD WITH AN EXTENSION
ACROSS THE SOUTHEAST. THE RIDGE GETS PUSHED BACK TO THE WEST AS A
STRONG SHORTWAVE MOVES ACROSS THE MIDWEST. THIS WILL LEAD TO
UNUSUALLY STRONG TROUGHING ACROSS THE SOUTHEAST THROUGH THE END OF
THE PERIOD. AT THE SURFACE HIGH PRESSURE MONDAY WILL GIVE WAY TO A
DECENT COLD FRONT ASSOCIATED WITH THE TROUGH THAT MOVES ACROSS
LATE TUESDAY AND WEDNESDAY. WE CONTINUE WITH GOOD POPS TUESDAY
LINGERING INTO WEDNESDAY. THURSDAY AND FRIDAY SHOULD SEE A DRYING
TREND. TEMPERATURES ARE A LITTLE ON THE WARM SIDE EARLY...DROPPING
TO SEASONAL NORMALS BY MID AND LATE WEEK.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AS OF 18Z...DYNAMIC CONDITIONS WITH DEEP MOISTURE IN PLACE. LOOK
FOR SCT SHRA AND ISOLD TSTMS TO FIRE AT ANY TIME TODAY AND
CONCENTRATED IN THE EASTERN PORTION OF THE CWA. CEILINGS AND VIS
WILL VARY FROM VFR TO POTENTIALLY LIFR IN THE HEAVIEST
ACTIVITY...BUT PREDOMINATELY MVFR. THE PRESSURE GRADIENT WILL BE
FAIRLY STRONG TODAY...WITH GUSTS OVER 20 KTS EXPECTED...STRONGER
IN CONVECTION. MOST OF THE ACTIVITY WILL END BY 00Z...WITH
ISOLATED ACTIVITY OVERNIGHT. WINDS SWING TO THE NORTH THIS EVENING
AS SURFACE LOW MOVES BY TO THE NORTHEAST. POST FRONTAL STRATUS IS
GOOD BET OVERNIGHT. SATURDAY...SLOWLY IMPROVING CONDITIONS BUT
STILL A CHANCE FOR PRECIP ALONG THE COAST.
EXTENDED OUTLOOK...PREDOMINATELY VFR SUNDAY. STORMS AGAIN MONDAY AND
TUESDAY...WITH PERIODS OF MVFR POSSIBLE. VFR WEDNESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 222 PM FRIDAY...THE COLD FRONT WAS POSITIONED NEAR A
KINGSTREE TO ELIZABETHTOWN LINE EARLY THIS AFTERNOON...AND WILL
MOVE OFFSHORE AND ACROSS THE COASTAL WATERS DURING THE EARLY
EVENING HOURS. THE PRESSURE GRADIENT ALONG AND BEHIND THE FRONT IS
RELATIVELY WEAK SO EXPECT NO ADVISORIES WILL BE REQUIRED. THE
POTENTIAL FOR SCATTERED SHOWERS AND A FEW THUNDERSTORMS WILL
CONTINUE UNTIL THE FRONT CLEARS THE COASTAL WATERS AROUND
MIDNIGHT.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 222 PM FRIDAY...MAIN MARINE HEADLINE REMAINS THE PREVAILING
NORTH WIND MUCH OF THE WEEKEND IN WAKE OF A COLD FRONT AND LOW
PRESSURE SYSTEM LINGERING OVER THE OFFSHORE WATERS SATURDAY AND
SUNDAY. BECAUSE OF THE WIND TRAJECTORY...TAMEST SEA CONDITIONS
WILL RESIDE NEAR SHORE...WHEREAS FARTHER OUT AS THE FETCH LENGTH
INCREASES...SEAS WILL BECOME INCREASINGLY BUMPY IN WIND-DEVELOPED
CHOP. WINDSPEEDS WILL BEGIN TO DECREASE THROUGH SUNDAY AS THE
SURFACE LOW PULLS FARTHER EAST TO SEA AND THE LOCAL PRESSURE
GRADIENT LOOSENS-UP. BY SUNDAY NIGHT OR EARLY MONDAY WINDS WILL
SWING AROUND TO THE S-SE LIGHTLY. SLIGHTLY BUMPY SATURDAY IN THE
EARLY GOING AS RESIDUAL SSW WAVES 3-4 FT EVERY 6 SEC INTERACT
WITH NNW WIND CHOP MAKING FOR A PITCHY SPECTRUM. A FEW TSTMS MAY
IMPACT THE OFFSHORE WATERS SATURDAY...MAINLY GULF STREAM WATERS.
LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 222 PM FRIDAY...LIGHT WINDS SHOULD PREVAIL OVER THE WATERS
MONDAY UNDER A WEAK PRESSURE GRADIENT. BY TUESDAY A DECENT SOUTHWEST
FLOW SETS UP AHEAD OF A COLD FRONT MOVING ACROSS THE APPALACHIANS.
THE FRONT WILL VERY SLOWLY MOVE ACROSS THE WATERS AND IN FACT...THIS
WILL OCCUR JUST AFTER THE END OF THIS FORECAST PERIOD. WITH THE
SOUTHWEST FLOW OF 15-20 KNOTS TUESDAY...SEAS COULD INCREASE TO 3-5
FEET FOR SOME TIME OTHERWISE THE STANDARD 2-4 FEET SHOULD SUFFICE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...CRM
SHORT TERM...MJC
LONG TERM...SHK
AVIATION...DL/CRM
AREA FORECAST DISCUSSION
NWS RALEIGH NC
622 AM EDT FRI AUG 7 2015
.SYNOPSIS...LOW PRESSURE AND A COLD FRONT WILL PUSH TO OUR SOUTHEAST
TODAY AND TONIGHT. HIGH PRESSURE WILL BUILD OVER THE REGION THIS
WEEKEND.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 622 AM FRIDAY...
QUICK UPDATE TO LOWER POPS ACROSS OUR WESTERN AND CENTRAL
ZONES...INCLUDING THE TRIAD. LATEST HRRR SHOWS THAT WHILE A FEW
SPOTTY SHOWERS ARE POSSIBLE ACROSS OUR WESTERN ZONES TODAY...THE
BEST CHANCE FOR RAIN TODAY WILL BE ACROSS OUR EAST AND NORTHEAST
ZONES. THIS IS SUPPORTED BY THE LATEST WATER VAPOR SATELLITE THAT
SHOWS THE SHORT WAVE TROUGH AXIS AND INFLECTION POINT NOW MOVING
ACROSS OUR NW ZONES...WITH SUBSIDENCE AND DRYING IN ITS WAKE.
PREV NEAR TERM DISC AS OF 320 AM FRIDAY...
LATEST WATER VAPOR SHOWS A WELL-DEFINED SHORT WAVE...THE CENTER OF
WHICH IS MOVING ACROSS SW VA...PROGRESSING EASTWARD. LATEST MODEL
SUITE SHOWS THIS SHORT WAVE MOVING ACROSS THE CAROLINAS DURING THE
DAYTIME TODAY...THEN SHIFTING OFFSHORE TONIGHT. AT THE SURFACE AT
07Z...LOW PRESSURE WAS NOTED JUST WEST OF KRDU...WITH A BOUNDARY
FROM KORF-KIGX-KSVH. THIS SFC LOW AND BOUNDARY WILL SHIFT TO THE
SOUTH AND EAST AS THE AFOREMENTIONED SHORT WAVE MOVES EAST. AS THE
DAY PROGRESSES...LOOK FOR RAIN TO DEVELOP INVOF OF THE BOUNDARY AS
IT SLOWLY PROGRESSES EASTWARD. THE BEST CHANCE FOR TSTM ACTIVITY
WILL BE ALONG, SOUTH, AND EAST OF THIS BOUNDARY WHERE THE UNSTABLE
AIRMASS WILL BE LOCATED. NORTH AND WEST OF THIS BOUNDARY...
INCREASINGLY STABLE AIRMASS SHOULD PRECLUDE THUNDER AND KEEP ANY
RAIN THAT OCCURS THERE ON THE LIGHTER SIDE. THE COMBINATION OF
CONSIDERABLE CLOUDINESS AND PRECIP...AND FALLING LOW LEVEL
THICKNESSES BEHIND THE FRONT WILL RESULT IN COOLER TEMPS...HIGHS
RANGING FROM AROUND 80 NW TO MID 80S SE.
WITH THE SFC BOUNDARY AND MID LEVEL SHORT WAVE SHIFTING OFFSHORE
TONIGHT...LOOK FOR FAIR WEATHER TONIGHT WITH LOWS 65-70...COOLEST NW.
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 320 AM FRIDAY...
A SHORT WAVE CURRENTLY OVER MN WILL MOVE SE TODAY AND TONIGHT...AND
ON SATURDAY WILL CROSS THE MID ATLANTIC REGION WHILE DROPPING INTO
THE BASE OF THE L/W TROUGH OFF THE EAST COAST. WHILE THIS SHORT WAVE
MAY RESULT IN A FEW SHOWERS ACROSS THE E/NE PORTION OF THE STATE...
CENTRAL NC IS EXPECTED TO REMAIN DRY. NE LOW LEVEL FLOW WILL KEEP
TEMPS A FEW DEGREES COOLER THAN NORMAL...HIGHS IN THE MID 80S. THEN
AS HIGH PRESSURE BUILDS TO OUR NORTH SATURDAY NIGHT...LOOK FOR
DECREASING CLOUDINESS AND COOLER TEMPS...LOWS 62-67...COOLEST NW.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 340 AM FRIDAY...
WEAK HIGH PRESSURE WILL RESIDE OVER THE REGION ON SUNDAY AS THE
UPPER TROUGH ALONG THE EAST COAST SHIFTS EAST AND HEIGHTS ALOFT
BRIEFLY BUILD OVER THE TN/OH VALLEY. MODELS SHOW A FEW WEAK
DISTURBANCES ROUNDING THE NORTHEAST PERIPHERY OF THE RIDGE BOTH
SUNDAY AND MONDAY...THOUGH MOISTURE RETURN AND AMPLE DESTABILIZATION
IS MORE LIKELY ON MONDAY...BEFORE A DEEPER PACIFIC SHORTWAVE IS
PROGGED TO TOP THE RIDGE AND THEN CARVE OUT A DEEPER EAST COAST
TROUGH TUESDAY/WEDNESDAY. A COLD FRONT ATTENDANT TO THE LATTER
SHORTWAVE WILL THEN PUSH INTO THE AREA FROM THE NORTHWEST BY TUESDAY
NIGHT. THE ECMWF AND GFS ARE SHOWING TYPICAL BIASES WITH THE RIDGE
BREAKING DOWN MORE QUICKLY IN THE GFS...AND THUS AN EARLIER ARRIVAL
OF THE FRONT. GIVEN SOME RUN-TO-RUN INCONSISTENCIES AND THE
POTENTIAL FOR CONVECTION TO INFLUENCE THE FRONT...WILL SPLIT THE
DIFFERENCE IN THE TWO MODELS FOR NOW AND SHOW THE FRONT (AND BEST
CHANCE POPS) MOVING INTO THE AREA TUESDAY AFTERNOON. THE FRONT WILL
THEN SETTLE SOUTH OF THE AREA BY WEDNESDAY AS THE ENTIRE UPPER LEVEL
PATTERN AMPLIFIES AND A RELATIVELY COOL HIGH SETTLES FROM THE
MIDWEST TO THE MID-ATLANTIC STATES FOR THE LATTER HALF OF THE WEEK.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 622 AM FRIDAY...
24-HOUR TAF PERIOD: LOW CLOUDS AND FOG WITH LOW-MVFR OR IFR
CONDITIONS EXPECTED THROUGH 14Z...ESP FROM KIXA-KHNZ-KBUY-KGSO-
KEXX...BASICALLY INVOF OF THE FRONT AND WHERE WINDS ARE LIGHT. THIS
WILL GRADUALLY IMPROVE AFTER 14Z THROUGH ABOUT 18Z...WHEN CIGS MAY
LIFT TO LOW-VFR. SHOWERS WILL BE POSSIBLE LATER TODAY MAINLY FROM
KFAY-KRWI...AND NORTHEASTWARD. LOW CLOUDS AND FOG EXPECTED AGAIN
TONIGHT INTO SATURDAY MORNING.
LOOKING AHEAD: VFR CONDITIONS EXPECTED TO RETURN AFTER SUNRISE
SATURDAY...LASTING THROUGH THE WEEKEND. SUB-VFR CONDITIONS POSSIBLE
EARLY NEXT WEEK ASSOC WITH THE NEXT FRONT.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RAH
NEAR TERM...RAH
SHORT TERM...RAH
LONG TERM...22
AVIATION...RAH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1000 PM CDT SAT AUG 8 2015
.UPDATE...
ISSUED AT 956 PM CDT SAT AUG 8 2015
MADE SOME POP CHANGES USING THE LATEST HRRR RUNS AND TRENDING
EARLY TOWARD THE RADAR. LIGHTNING IS SLOWLY CREEPING TOWARD THE
BORDER. LOOKS LIKE MUCH OF THE EARLY PRECIP SUFFERED FROM WEAK
FORCING AND EVAPORATION BELOW CLOUDS BASE. NOW LOOKS LIKE MORE
SUBSTANTIAL SHOWERS/THUNDERSTORMS WILL MOVE INTO SOUTHWEST ND AS
MIDNIGHT APPROACHES.
UPDATE ISSUED AT 646 PM CDT SAT AUG 8 2015
RADAR TRENDS SHOW SEVERAL BANDS OF PRECIPITATION MOVING INTO SOUTHWEST
AND SOUTH CENTRAL NORTH DAKOTA. SO FAR VERY LITTLE IF ANY APPEARS
TO BE REACHING THE GROUND AS OF 630 PM CDT. ONE REASON MAY BE THE
DRY SUBCLOUD LAYER RESULTING IN CONSIDERABLE EVAPORATION. EVENTUALLY
THERE WILL BE RAIN SOUTHWEST. WILL CONTINUE THE HIGHER POPS TREND
WITH TIME THIS EVENING ACROSS THE FAR SOUTHWEST AND SOUTH CENTRAL.
LITTLE RAIN WILL REACH THE AREA NORTH OF I94 EVEN THROUGH MUSH OF
THE DAY TOMORROW. SO FAR INSTABILITY IS SLIM SO REDUCED THE TREAT
FOR THUNDERSTORMS TO WIDELY SCATTERED.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 238 PM CDT SAT AUG 8 2015
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE CHANCES FOR
SHOWERS AND ISOLATED THUNDERSTORMS SOUTHWEST THIS
AFTERNOON...EXPANDING INTO THE SOUTH CENTRAL TONIGHT...WITH
THUNDERSTORM CHANCES CONTINUING ON SUNDAY ACROSS THE SOUTH.
CURRENTLY...TRANSITIONAL FLOW ALOFT WAS OCCURRING OVER SOUTHWESTERN
NORTH DAKOTA...FROM ZONAL/WEAK RIDGE ALOFT TO SOUTHWESTERLY. THE
STACKED LOW PRESSURE SYSTEM OVER MANITOBA CONTINUED MOVING EAST
TODAY AS AN UPPER LEVEL SHORTWAVE TROUGH PROGRESSES NORTHEASTWARD
OUT OF IDAHO ACROSS WYOMING AND MONTANA. THIS IDAHO SHORTWAVE WAS
UNDERCUTTING A LARGER WESTERN RIDGE THAT EXTENDED NORTHWARD OVER THE
CANADIAN ROCKIES. MEANWHILE AT THE SURFACE...A COLD FRONT EXTENDING
FROM THE MANITOBA LOW HAD MOVED THROUGH ALL OF WESTERN AND MOST OF
CENTRAL NORTH DAKOTA. DEWPOINTS WERE IN THE 40S IN THE WEST...50S
CENTRAL...WITH A VERY HUMID 70 READING AT OAKES SOUTH OF JAMESTOWN.
THE MODELS ARE IN AGREEMENT THAT THE ZONAL/WEAK RIDGING ALOFT WAS
SLOWING THE PROGRESSION OF SHOWERS INTO SOUTHWESTERN NORTH DAKOTA
EARLIER TODAY. LATEST REGIONAL RADAR LOOPS INDICATE LIGHT SHOWERS
MOVING INTO THE BOWMAN/HETTINGER AREAS. CONFIDENCE IS LOW AS TO
WHETHER THIS REFLECTS SHOWERS REACHING THE GROUND OR VIRGA. IN ANY
CASE...THE MODELS ARE INDICATING THE VIGOROUS SHORTWAVE MOVING INTO
THE SOUTHWEST WILL CONTINUE TO PROVIDE MID-LEVEL BASED SHOWERS
THROUGH TONIGHT AND INTO SUNDAY. AT SOME POINT...SHOWERS SHOULD
REACH THE GROUND AS THE CONVECTION CONTINUES ITS ADVANCEMENT AND
FORCING INCREASES.
THE MODELS ALSO INDICATE THAT RIDGING ALOFT OVER THE CANADIAN
ROCKIES SHOULD LIMIT THE NORTHERN EXTENT OF THE CONVECTION...AND
ONLY THE SOUTHERN HALF OF WESTERN AND CENTRAL NORTH DAKOTA SHOULD
HAVE CHANCES OF SHOWERS/THUNDER.
LIMITED CAPE THIS EVENING AND OVERNIGHT...BUT CAPE INCREASES ON
SUNDAY. THEREFORE ISOLATED THUNDERSTORMS EXPECTED WITH SHOWERS
TONIGHT...WITH CHANCES OF SHOWERS AND THUNDERSTORMS SUNDAY. BEST
CHANCES ALONG THE SOUTHERN TIER OF COUNTIES.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 238 PM CDT SAT AUG 8 2015
THE LONG TERM LOOKS WARM AND MAINLY DRY...WITH SLIGHT CHANCES FOR
THUNDERSTORMS LATER NEXT WEEK.
THE MODELS ARE IN FAIRLY GOOD AGREEMENT ABOUT BUILDING IN A HIGH
AMPLITUDE RIDGE ACROSS THE MOUNTAIN WEST. THE RIDGE IS EXPECTED
TO START BUILDING IN SUNDAY ACROSS THE WESTERN ROCKIES. BOTH THE
GFS AND ECMWF HAVE THE RIDGE EVER SO SLOWLY PROPAGATING EASTWARD
THROUGH NEXT WEEK. SOME OF THE WARMEST AIR OF THE YEAR IS POSSIBLE
ACROSS WESTERN NORTH DAKOTA THIS WEEK. TEMPERATURES IN THE UPPER
90S SEEM LIKELY...WITH SOME 100S POSSIBLE. SEVERAL FAST MOVING
SHORTWAVE TROUGHS WILL LIKELY TRAVERSE THE RIDGE MID/LATE NEXT
WEEK. HOWEVER...TIMING OF INDIVIDUAL WAVES AND ASSOCIATED
PRECIPITATION IS DIFFICULT AT BEST THIS FAR OUT.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 646 PM CDT SAT AUG 8 2015
MAIN HAZARD TO AVIATION WILL BE POSSIBLE MVFR CONDITIONS IN CLOUDS
AND RAIN ACROSS SOUTHWEST NORTH DAKOTA TONIGHT. ISOLATED
THUNDERSTORMS ARE POSSIBLE KDIK AFTER 05Z. OTHERWISE VFR.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...JV
LONG TERM...AJ
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1251 PM CDT FRI AUG 7 2015
.UPDATE...
ISSUED AT 1242 PM CDT FRI AUG 7 2015
FRONTAL BOUNDARY SITUATED FROM AROUND HARVEY TO BISMARCK EARLY
THIS AFTERNOON. STILL A CHANCE OF A SHOWER OR THUNDERSTORM SOUTH
AND EAST OF THE FRONT THIS AFTERNOON. LATEST HRRR ITERATION IS
INDICATING CONVECTION DEVELOPING AROUND ASHLEY TO EDGELEY AND
ELLENDALE AROUND 20-21 UTC. INCREASING INSTABILITY OVER THIS AREA
WITH MLCAPES AROUND 1000-1500 J/KG ALONG THE SOUTH DAKOTA BORDER
AND 40 KNOTS OF BULK SHEAR. WILL NEED TO MONITOR THIS AREA FOR
STRONG CONVECTION YET THIS AFTERNOON. OTHERWISE...MOSTLY SUNNY
SKIES EARLY THIS AFTERNOON. EXPECT INCREASING CLOUDS AND WINDS
ACROSS THE NORTH ASSOCIATED WITH THE UPPER LEVEL LOW IN SOUTHERN
CANADA. CURRENT FORECAST HAS A GOOD HANDLE ON THIS.
UPDATE ISSUED AT 918 AM CDT FRI AUG 7 2015
SURFACE AND UPPER LEVEL LOW OVER SOUTHEAST SASKATCHEWAN WITH A
COLD FRONT MOVING THROUGH CENTRAL NORTH DAKOTA. SCATTERED SHOWERS
AND ISOLATED THUNDER ALONG THE FRONT WILL TRACK ACROSS CENTRAL
NORTH DAKOTA THIS MORNING. WILL KEEP THE THREAT OF THUNDER OVER
THE SOUTHEAST CWA INTO THE AFTERNOON WITH FRONT LAGGING HERE AND
MOVING INTO A MORE UNSTABLE AIRMASS. FOR THE MORNING UPDATE...MAIN
MAIN CHANGE WAS CLOUDS AND POPS BASED ON LATEST SATELLITE AND
RADAR. ALSO...FOG HAS RAPIDLY DISSIPATED DURING THE PAST HOUR OR
SO.
UPDATE ISSUED AT 618 AM CDT FRI AUG 7 2015
FOG IS CLEARLY EVIDENT VIA WEBCAMS THIS MORNING. THE LAYER IS
QUITE THIN AS THE MOON IS VISIBLE WHEN LOOKING UP...DESPITE LESS
THAN 1/4 MILE VISIBILITY WHEN LOOKING HORIZONTALLY. LIGHT
PRECIPITATION MOVING THROUGH SOUTH CENTRAL SHOULD DISSIPATE FOG
RAPIDLY THIS MORNING.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CDT FRI AUG 7 2015
FORECAST HIGHLIGHT IN THE SHORT TERM PERIOD IS FOG THIS MORNING.
CURRENTLY...ZONAL FLOW ALOFT WITH DEEP LOW PRESSURE OVER FAR
SOUTH CENTRAL CANADA AND RIDGING OVER THE SOUTHERN AND CENTRAL
PLAINS. BAND OF SHOWERS OVER SOUTHEAST MONTANA STRETCHING EASTWARD
INTO FAR SOUTHWEST NORTH DAKOTA ALONG A COLD FRONTAL BOUNDARY AND
UNDERNEATH AN UPPER JET. HIGH RES MODELS CONTINUE TO BRING THIS
PRECIPITATION INTO MY SOUTHWEST NOW THROUGH 10Z...SPREADING EAST
INTO MY SOUTH CENTRAL COUNTIES THROUGH THE AM HOURS. A FEW
LIGHTNING STRIKES BUT WILL KEEP THUNDER OUT OF THE MORNING
FORECAST WITH LITTLE TO NO CAPE ACROSS SOUTHERN NORTH DAKOTA.
AREAS OF FOG MAINLY OVER NORTHWESTERN...CENTRAL AND EASTERN
PORTIONS OF THE STATE. LATEST HRRR VISIBILITY OUTPUT INDICATES FOG
PERSISTING UNTIL 12-15Z THIS MORNING ACROSS THE AFOREMENTIONED
AREAS. HRRR DOES REMOVE FOG NORTHWEST WHERE WE CURRENTLY HAVE
INCREASING UPPER CLOUDS AND WHERE WINDS WILL SHIFT TO SOUTHWEST
PROMOTING DRY AIR ADVECTION. WITH VISIBILITIES COMING UP AND DOWN
OPTING TO GO WITH A SPECIAL WEATHER STATEMENT FOR NOW HIGHLIGHTING
THE FOG VERSUS HEADLINES.
CHANCES FOR PRECIPITATION WILL CONTINUE TO MOVE EAST ACROSS THE
SOUTH NEAR THE COLD FRONTAL BOUNDARY TODAY INTO THE EVENING HOURS
WHEN FORCING ALOFT WILL BE PRESENT WITH THE UPPER JET. WILL
MENTION THUNDER POTENTIAL IN THE AFTERNOON AND EVENING WHEN
DAYTIME HEATING WILL RESULT IN DIURNAL INSTABILITY. FORCING
DECREASING LATER THIS EVENING SO WENT DRY OVERNIGHT. BREEZY ACROSS
THE NORTH TODAY NEAR THE UPPER LOW...SUB WIND ADVISORY MAGNITUDES.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 322 AM CDT FRI AUG 7 2015
THE MAIN FORECAST FOCUS IS ON THE POTENTIAL FOR PRECIPITATION ALONG
AND SOUTH OF I-94 THIS WEEKEND.
FAR SOUTHERN NORTH DAKOTA AND THE NORTHERN THIRD OF SOUTH DAKOTA ARE
THE CONSENSUS HOT SPOT FOR CONVECTION SATURDAY NIGHT AND
SUNDAY...ACCORDING TO THE 00 UTC GFS/ECMWF/GEFS/GEM GLOBAL
CONSENSUS. THUNDERSTORMS WILL LIKELY MOVE SLOWLY...BUT FLOOD RISK IS
LOW GIVEN LACK OF ANOMALOUS PRECIPITABLE WATER AND RECENT
DEMONSTRATION THAT SOILS CAN HANDLE OVER TWO INCHES PER HOUR WITHOUT
FLASH FLOODING.
IN ITS WAKE...THERE IS GENERAL CONSENSUS AMONG THE 00 UTC
GFS/ECMWF/GEFS/GEM GLOBAL SUITE THAT COMPLEX UPPER LEVEL FLOW WILL
EVOLVE INTO A SIMPLER WEST COAST TROUGH WITH AMPLIFIED RIDGING OVER
THE GREAT PLAINS BY MONDAY MORNING. ASSOCIATED BROAD SCALE
SUBSIDENCE SHOULD BE SUFFICIENT TO SQUELCH CONVECTION UNTIL AT LEAST
WEDNESDAY MORNING. UNCERTAINTY INCREASES THEREAFTER AS SEVERAL
ENSEMBLE MEMBERS EJECT SHORTWAVE ENERGY INTO EASTERN MONTANA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1242 PM CDT FRI AUG 7 2015
VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD. SCATTERED
THUNDERSTORMS POSSIBLE OVER SOUTHEAST NORTH DAKOTA THIS AFTERNOON
BUT AT THIS TIME THINK BEST CHANCES WILL REMAIN SOUTH AND EAST OF
KJMS...THUS NO MENTION OF THUNDER FOR THE KJMS TAF.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...NH
LONG TERM...SCHECK
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1235 PM CDT FRI AUG 7 2015
.UPDATE...
ISSUED AT 1235 PM CDT FRI AUG 7 2015
MADE SOME MINOR ADJUSTMENTS TO CLOUD AND PCPN TRENDS FOR THIS
UPDATE. STILL WATCHING WAVE MOVG ACROSS SRN CANADA AND SFC TROF
ACROSS ND FOR DEVELOPMENT OF LATE AFTERNOON AND EVENING
CONVECTION...AND CURRENT TIMING STILL LOOKS GOOD. REST OF FCST
REMAINS ON TARGET.
UPDATE ISSUED AT 954 AM CDT FRI AUG 7 2015
BASED ON CURRENT TRENDS...INCREASED SKY COVER OVER THE AREA AND
ADDED SOME -RW OVER ERN ND. CURRENT RADAR SHOWS A BAND OF SHOWERS
MOVG INTO THE DVL BASIN AND EXPECT THEM TO CONTINUE E THRU THE
MORNING INTO THE EARLY AFTERNOON HOURS. OTHERWISE...REST OF FCST
LOOKS GOOD.
UPDATE ISSUED AT 632 AM CDT FRI AUG 7 2015
AREAS OF DENSE FOG REMAIN...BUT CONDITIONS APPEAR TO BE SLOWLY
IMPROVING. MAIN CONCERN IS STILL SEVERE POTENTIAL THIS AFTERNOON.
LATEST HRRR DEVELOPS STORMS BY 19Z-20Z...BUT IS USUALLY TOO QUICK
WITH BREAKING THE CAP AND WILL STICK WITH AFTER 21Z TIMING. WILL
NEED TO MONITOR MESOANALYSIS THROUGH THE MORNING TO DETERMINE
EXTENT OF SEVERE POTENTIAL.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 345 AM CDT FRI AUG 7 2015
PATCHY FOG ACROSS THE REGION THIS MORNING WILL DISSIPATE JUST
AFTER SUNRISE.
MAIN CONCERN WILL BE SEVERE POTENTIAL FOR THIS AFTERNOON. STRONG
UPPER LOW ACROSS SOUTHERN CANADA WILL CONTINUE TO PROPAGATE
EASTWARD...SENDING A SFC TROUGH THROUGH THE REGION THIS AFTERNOON.
MLCAPE AHEAD OF THIS FEATURE EXPECTED TO REACH NEAR 2000 J/KG.
SFC CONVERGENCE WILL BE RELATIVELY WEAK (WITH STRONGEST FORCING
REMAIN ACROSS CANADA)...AND COVERAGE OF STORMS WILL BE LIMITED TO
ISOLD/SCT. HOWEVER...GIVEN 0-6KM BULK SHEAR 35-40 KNTS...ANY
STORM THAT DOES INITIATE WILL HAVE THE POTENTIAL TO BECOME SEVERE.
SPC INDICATES A MARGINAL RISK FOR SEVERE STORMS CLOSER TO THE
INTERNATIONAL BORDER...WHICH IS CLOSER TO THE UPPER LOW.
THE NEXT UPPER WAVE WILL APPROACH THE REGION FROM THE SOUTHWEST ON
SATURDAY...BRINING THUNDER CHANCES TO THE SOUTHERN FA (ALONG WITH
STALLED SFC TROUGH). MOST GUIDANCE SUGGESTS STRONGER INSTABILITY
WILL REMAIN SOUTH OF THE REGION...SIGNIFICANTLY LIMITING SEVERE
POTENTIAL.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 345 AM CDT FRI AUG 7 2015
SATURDAY NIGHT-SUNDAY NIGHT...MOST GUIDANCE SUGGESTS HIGH PRESSURE
AND A DRIER AIRMASS WILL BE IN PLACE BY SUNDAY ACROSS THE
REGION...LEADING TO DRY WEATHER. THE OUTLIER IS THE ECMWF WHICH
ATTEMPTS TO MOVE AN UPPER WAVE INTO THE REGION ON SUNDAY. KEPT LOW
POPS ACROSS SE ND...ALTHOUGH ANY ACTIVITY SHOULD REMAIN WEAK GIVEN
THE VERY WEAK INSTABILITY THE MODELS ARE INDICATING.
MONDAY-THURSDAY...EXTENDED PERIOD FEATURES MAINLY DRY CONDITIONS
AT LEAST THROUGH WEDNESDAY AS AN UPPER RIDGE DOMINATES THE HIGH
PLAINS AND EDGES TOWARD THE FORECAST AREA WITH TIME. THIS WILL
TRANSLATE TO SURFACE TEMPERATURES IN THE SEASONALLY WARM LOW TO
MID EIGHTIES DURING THE MIDDLE OF THE WEEK. UPPER LOW ANCHORED
VICINITY OF PACIFIC NORTHWEST WILL MOVE SLOWLY TO THE EAST...SHORT
WAVE(S) OUT AHEAD COULD AFFECT OUR AREA WITH RW/TRW ACTIVITY BY
THURSDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1235 PM CDT FRI AUG 7 2015
SOME BRIEF MVFR CU CIGS CAN BE EXPECTED GENERALLY EAST OF THE VALLEY
EARLY THIS AFTERNOON BEFORE LIFTING INTO VFR RANGE AND SCATTERING BY
LATE AFTERNOON. TSRA PSBL LATE AFTERNOON AND EARLY EVENING MAINLY
OVER THE FAR NORTH HOWEVER FAVORED GUIDANCE SHOWING ANY TSRA ISOLD
SO FOR NOW WILL OMIT FROM TAFS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...HOPKINS
SHORT TERM...TG
LONG TERM...WJB/TG
AVIATION...VOELKER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
954 AM CDT FRI AUG 7 2015
.UPDATE...
ISSUED AT 954 AM CDT FRI AUG 7 2015
BASED ON CURRENT TRENDS...INCREASED SKY COVER OVER THE AREA AND
ADDED SOME -RW OVER ERN ND. CURRENT RADAR SHOWS A BAND OF SHOWERS
MOVG INTO THE DVL BASIN AND EXPECT THEM TO CONTINUE E THRU THE
MORNING INTO THE EARLY AFTERNOON HOURS. OTHERWISE...REST OF FCST
LOOKS GOOD.
UPDATE ISSUED AT 632 AM CDT FRI AUG 7 2015
AREAS OF DENSE FOG REMAIN...BUT CONDITIONS APPEAR TO BE SLOWLY
IMPROVING. MAIN CONCERN IS STILL SEVERE POTENTIAL THIS AFTERNOON.
LATEST HRRR DEVELOPS STORMS BY 19Z-20Z...BUT IS USUALLY TOO QUICK
WITH BREAKING THE CAP AND WILL STICK WITH AFTER 21Z TIMING. WILL
NEED TO MONITOR MESOANALYSIS THROUGH THE MORNING TO DETERMINE
EXTENT OF SEVERE POTENTIAL.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 345 AM CDT FRI AUG 7 2015
PATCHY FOG ACROSS THE REGION THIS MORNING WILL DISSIPATE JUST
AFTER SUNRISE.
MAIN CONCERN WILL BE SEVERE POTENTIAL FOR THIS AFTERNOON. STRONG
UPPER LOW ACROSS SOUTHERN CANADA WILL CONTINUE TO PROPAGATE
EASTWARD...SENDING A SFC TROUGH THROUGH THE REGION THIS AFTERNOON.
MLCAPE AHEAD OF THIS FEATURE EXPECTED TO REACH NEAR 2000 J/KG.
SFC CONVERGENCE WILL BE RELATIVELY WEAK (WITH STRONGEST FORCING
REMAIN ACROSS CANADA)...AND COVERAGE OF STORMS WILL BE LIMITED TO
ISOLD/SCT. HOWEVER...GIVEN 0-6KM BULK SHEAR 35-40 KNTS...ANY
STORM THAT DOES INITIATE WILL HAVE THE POTENTIAL TO BECOME SEVERE.
SPC INDICATES A MARGINAL RISK FOR SEVERE STORMS CLOSER TO THE
INTERNATIONAL BORDER...WHICH IS CLOSER TO THE UPPER LOW.
THE NEXT UPPER WAVE WILL APPROACH THE REGION FROM THE SOUTHWEST ON
SATURDAY...BRINING THUNDER CHANCES TO THE SOUTHERN FA (ALONG WITH
STALLED SFC TROUGH). MOST GUIDANCE SUGGESTS STRONGER INSTABILITY
WILL REMAIN SOUTH OF THE REGION...SIGNIFICANTLY LIMITING SEVERE
POTENTIAL.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 345 AM CDT FRI AUG 7 2015
SATURDAY NIGHT-SUNDAY NIGHT...MOST GUIDANCE SUGGESTS HIGH PRESSURE
AND A DRIER AIRMASS WILL BE IN PLACE BY SUNDAY ACROSS THE
REGION...LEADING TO DRY WEATHER. THE OUTLIER IS THE ECMWF WHICH
ATTEMPTS TO MOVE AN UPPER WAVE INTO THE REGION ON SUNDAY. KEPT LOW
POPS ACROSS SE ND...ALTHOUGH ANY ACTIVITY SHOULD REMAIN WEAK GIVEN
THE VERY WEAK INSTABILITY THE MODELS ARE INDICATING.
MONDAY-THURSDAY...EXTENDED PERIOD FEATURES MAINLY DRY CONDITIONS
AT LEAST THROUGH WEDNESDAY AS AN UPPER RIDGE DOMINATES THE HIGH
PLAINS AND EDGES TOWARD THE FORECAST AREA WITH TIME. THIS WILL
TRANSLATE TO SURFACE TEMPERATURES IN THE SEASONALLY WARM LOW TO
MID EIGHTIES DURING THE MIDDLE OF THE WEEK. UPPER LOW ANCHORED
VICINITY OF PACIFIC NORTHWEST WILL MOVE SLOWLY TO THE EAST...SHORT
WAVE(S) OUT AHEAD COULD AFFECT OUR AREA WITH RW/TRW ACTIVITY BY
THURSDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 632 AM CDT FRI AUG 7 2015
FOG WILL DISSIPATE QUICKLY THIS MORNING...LEADING TO VFR
CONDITIONS THROUGH THE DAY. ALTHOUGH THERE IS A CHANCE FOR
THUNDERSTORMS THIS AFTERNOON...COVERAGE IS EXPECTED TO REMAIN
LIMITED.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...HOPKINS
SHORT TERM...TG
LONG TERM...WJB/TG
AVIATION...TG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
929 AM CDT FRI AUG 7 2015
.UPDATE...
ISSUED AT 918 AM CDT FRI AUG 7 2015
SURFACE AND UPPER LEVEL LOW OVER SOUTHEAST SASKATCHEWAN WITH A
COLD FRONT MOVING THROUGH CENTRAL NORTH DAKOTA. SCATTERED SHOWERS
AND ISOLATED THUNDER ALONG THE FRONT WILL TRACK ACROSS CENTRAL
NORTH DAKOTA THIS MORNING. WILL KEEP THE THREAT OF THUNDER OVER
THE SOUTHEAST CWA INTO THE AFTERNOON WITH FRONT LAGGING HERE AND
MOVING INTO A MORE UNSTABLE AIRMASS. FOR THE MORNING UPDATE...MAIN
MAIN CHANGE WAS CLOUDS AND POPS BASED ON LATEST SATELLITE AND
RADAR. ALSO...FOG HAS RAPIDLY DISSIPATED DURING THE PAST HOUR OR
SO.
UPDATE ISSUED AT 618 AM CDT FRI AUG 7 2015
FOG IS CLEARLY EVIDENT VIA WEBCAMS THIS MORNING. THE LAYER IS
QUITE THIN AS THE MOON IS VISIBLE WHEN LOOKING UP...DESPITE LESS
THAN 1/4 MILE VISIBILITY WHEN LOOKING HORIZONTALLY. LIGHT
PRECIPITATION MOVING THROUGH SOUTH CENTRAL SHOULD DISSIPATE FOG
RAPIDLY THIS MORNING.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CDT FRI AUG 7 2015
FORECAST HIGHLIGHT IN THE SHORT TERM PERIOD IS FOG THIS MORNING.
CURRENTLY...ZONAL FLOW ALOFT WITH DEEP LOW PRESSURE OVER FAR
SOUTH CENTRAL CANADA AND RIDGING OVER THE SOUTHERN AND CENTRAL
PLAINS. BAND OF SHOWERS OVER SOUTHEAST MONTANA STRETCHING EASTWARD
INTO FAR SOUTHWEST NORTH DAKOTA ALONG A COLD FRONTAL BOUNDARY AND
UNDERNEATH AN UPPER JET. HIGH RES MODELS CONTINUE TO BRING THIS
PRECIPITATION INTO MY SOUTHWEST NOW THROUGH 10Z...SPREADING EAST
INTO MY SOUTH CENTRAL COUNTIES THROUGH THE AM HOURS. A FEW
LIGHTNING STRIKES BUT WILL KEEP THUNDER OUT OF THE MORNING
FORECAST WITH LITTLE TO NO CAPE ACROSS SOUTHERN NORTH DAKOTA.
AREAS OF FOG MAINLY OVER NORTHWESTERN...CENTRAL AND EASTERN
PORTIONS OF THE STATE. LATEST HRRR VISIBILITY OUTPUT INDICATES FOG
PERSISTING UNTIL 12-15Z THIS MORNING ACROSS THE AFOREMENTIONED
AREAS. HRRR DOES REMOVE FOG NORTHWEST WHERE WE CURRENTLY HAVE
INCREASING UPPER CLOUDS AND WHERE WINDS WILL SHIFT TO SOUTHWEST
PROMOTING DRY AIR ADVECTION. WITH VISIBILITIES COMING UP AND DOWN
OPTING TO GO WITH A SPECIAL WEATHER STATEMENT FOR NOW HIGHLIGHTING
THE FOG VERSUS HEADLINES.
CHANCES FOR PRECIPITATION WILL CONTINUE TO MOVE EAST ACROSS THE
SOUTH NEAR THE COLD FRONTAL BOUNDARY TODAY INTO THE EVENING HOURS
WHEN FORCING ALOFT WILL BE PRESENT WITH THE UPPER JET. WILL
MENTION THUNDER POTENTIAL IN THE AFTERNOON AND EVENING WHEN
DAYTIME HEATING WILL RESULT IN DIURNAL INSTABILITY. FORCING
DECREASING LATER THIS EVENING SO WENT DRY OVERNIGHT. BREEZY ACROSS
THE NORTH TODAY NEAR THE UPPER LOW...SUB WIND ADVISORY MAGNITUDES.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 322 AM CDT FRI AUG 7 2015
THE MAIN FORECAST FOCUS IS ON THE POTENTIAL FOR PRECIPITATION ALONG
AND SOUTH OF I-94 THIS WEEKEND.
FAR SOUTHERN NORTH DAKOTA AND THE NORTHERN THIRD OF SOUTH DAKOTA ARE
THE CONSENSUS HOT SPOT FOR CONVECTION SATURDAY NIGHT AND
SUNDAY...ACCORDING TO THE 00 UTC GFS/ECMWF/GEFS/GEM GLOBAL
CONSENSUS. THUNDERSTORMS WILL LIKELY MOVE SLOWLY...BUT FLOOD RISK IS
LOW GIVEN LACK OF ANOMALOUS PRECIPITABLE WATER AND RECENT
DEMONSTRATION THAT SOILS CAN HANDLE OVER TWO INCHES PER HOUR WITHOUT
FLASH FLOODING.
IN ITS WAKE...THERE IS GENERAL CONSENSUS AMONG THE 00 UTC
GFS/ECMWF/GEFS/GEM GLOBAL SUITE THAT COMPLEX UPPER LEVEL FLOW WILL
EVOLVE INTO A SIMPLER WEST COAST TROUGH WITH AMPLIFIED RIDGING OVER
THE GREAT PLAINS BY MONDAY MORNING. ASSOCIATED BROAD SCALE
SUBSIDENCE SHOULD BE SUFFICIENT TO SQUELCH CONVECTION UNTIL AT LEAST
WEDNESDAY MORNING. UNCERTAINTY INCREASES THEREAFTER AS SEVERAL
ENSEMBLE MEMBERS EJECT SHORTWAVE ENERGY INTO EASTERN MONTANA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 918 AM CDT FRI AUG 7 2015
AREAS OF FOG ACROSS THE REGION WITH SHORT RANGE MODELS HINTING AT
FOG PERSISTING UNTIL 13-15Z. LIFR-VLIFR CIGS ALSO OCCURRING WITH THE
FOG. VFR FOR THE REMAINDER OF THE PERIOD.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...NH
LONG TERM...SCHECK
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
632 AM CDT FRI AUG 7 2015
.UPDATE...
ISSUED AT 632 AM CDT FRI AUG 7 2015
AREAS OF DENSE FOG REMAIN...BUT CONDITIONS APPEAR TO BE SLOWLY
IMPROVING. MAIN CONCERN IS STILL SEVERE POTENTIAL THIS AFTERNOON.
LATEST HRRR DEVELOPS STORMS BY 19Z-20Z...BUT IS USUALLY TOO QUICK
WITH BREAKING THE CAP AND WILL STICK WITH AFTER 21Z TIMING. WILL
NEED TO MONITOR MESOANALYSIS THROUGH THE MORNING TO DETERMINE
EXTENT OF SEVERE POTENTIAL.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 345 AM CDT FRI AUG 7 2015
PATCHY FOG ACROSS THE REGION THIS MORNING WILL DISSIPATE JUST
AFTER SUNRISE.
MAIN CONCERN WILL BE SEVERE POTENTIAL FOR THIS AFTERNOON. STRONG
UPPER LOW ACROSS SOUTHERN CANADA WILL CONTINUE TO PROPAGATE
EASTWARD...SENDING A SFC TROUGH THROUGH THE REGION THIS AFTERNOON.
MLCAPE AHEAD OF THIS FEATURE EXPECTED TO REACH NEAR 2000 J/KG.
SFC CONVERGENCE WILL BE RELATIVELY WEAK (WITH STRONGEST FORCING
REMAIN ACROSS CANADA)...AND COVERAGE OF STORMS WILL BE LIMITED TO
ISOLD/SCT. HOWEVER...GIVEN 0-6KM BULK SHEAR 35-40 KNTS...ANY
STORM THAT DOES INITIATE WILL HAVE THE POTENTIAL TO BECOME SEVERE.
SPC INDICATES A MARGINAL RISK FOR SEVERE STORMS CLOSER TO THE
INTERNATIONAL BORDER...WHICH IS CLOSER TO THE UPPER LOW.
THE NEXT UPPER WAVE WILL APPROACH THE REGION FROM THE SOUTHWEST ON
SATURDAY...BRINING THUNDER CHANCES TO THE SOUTHERN FA (ALONG WITH
STALLED SFC TROUGH). MOST GUIDANCE SUGGESTS STRONGER INSTABILITY
WILL REMAIN SOUTH OF THE REGION...SIGNIFICANTLY LIMITING SEVERE
POTENTIAL.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 345 AM CDT FRI AUG 7 2015
SATURDAY NIGHT-SUNDAY NIGHT...MOST GUIDANCE SUGGESTS HIGH PRESSURE
AND A DRIER AIRMASS WILL BE IN PLACE BY SUNDAY ACROSS THE
REGION...LEADING TO DRY WEATHER. THE OUTLIER IS THE ECMWF WHICH
ATTEMPTS TO MOVE AN UPPER WAVE INTO THE REGION ON SUNDAY. KEPT LOW
POPS ACROSS SE ND...ALTHOUGH ANY ACTIVITY SHOULD REMAIN WEAK GIVEN
THE VERY WEAK INSTABILITY THE MODELS ARE INDICATING.
MONDAY-THURSDAY...EXTENDED PERIOD FEATURES MAINLY DRY CONDITIONS
AT LEAST THROUGH WEDNESDAY AS AN UPPER RIDGE DOMINATES THE HIGH
PLAINS AND EDGES TOWARD THE FORECAST AREA WITH TIME. THIS WILL
TRANSLATE TO SURFACE TEMPERATURES IN THE SEASONALLY WARM LOW TO
MID EIGHTIES DURING THE MIDDLE OF THE WEEK. UPPER LOW ANCHORED
VICINITY OF PACIFIC NORTHWEST WILL MOVE SLOWLY TO THE EAST...SHORT
WAVE(S) OUT AHEAD COULD AFFECT OUR AREA WITH RW/TRW ACTIVITY BY
THURSDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 632 AM CDT FRI AUG 7 2015
FOG WILL DISSIPATE QUICKLY THIS MORNING...LEADING TO VFR
CONDITIONS THROUGH THE DAY. ALTHOUGH THERE IS A CHANCE FOR
THUNDERSTORMS THIS AFTERNOON...COVERAGE IS EXPECTED TO REMAIN
LIMITED.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...TG
SHORT TERM...TG
LONG TERM...WJB/TG
AVIATION...TG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
628 AM CDT FRI AUG 7 2015
.UPDATE...
ISSUED AT 618 AM CDT FRI AUG 7 2015
FOG IS CLEARLY EVIDENT VIA WEBCAMS THIS MORNING. THE LAYER IS
QUITE THIN AS THE MOON IS VISIBLE WHEN LOOKING UP...DESPITE LESS
THAN 1/4 MILE VISIBILITY WHEN LOOKING HORIZONTALLY. LIGHT
PRECIPITATION MOVING THROUGH SOUTH CENTRAL SHOULD DISSIPATE FOG
RAPIDLY THIS MORNING.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CDT FRI AUG 7 2015
FORECAST HIGHLIGHT IN THE SHORT TERM PERIOD IS FOG THIS MORNING.
CURRENTLY...ZONAL FLOW ALOFT WITH DEEP LOW PRESSURE OVER FAR
SOUTH CENTRAL CANADA AND RIDGING OVER THE SOUTHERN AND CENTRAL
PLAINS. BAND OF SHOWERS OVER SOUTHEAST MONTANA STRETCHING EASTWARD
INTO FAR SOUTHWEST NORTH DAKOTA ALONG A COLD FRONTAL BOUNDARY AND
UNDERNEATH AN UPPER JET. HIGH RES MODELS CONTINUE TO BRING THIS
PRECIPITATION INTO MY SOUTHWEST NOW THROUGH 10Z...SPREADING EAST
INTO MY SOUTH CENTRAL COUNTIES THROUGH THE AM HOURS. A FEW
LIGHTNING STRIKES BUT WILL KEEP THUNDER OUT OF THE MORNING
FORECAST WITH LITTLE TO NO CAPE ACROSS SOUTHERN NORTH DAKOTA.
AREAS OF FOG MAINLY OVER NORTHWESTERN...CENTRAL AND EASTERN
PORTIONS OF THE STATE. LATEST HRRR VISIBILITY OUTPUT INDICATES FOG
PERSISTING UNTIL 12-15Z THIS MORNING ACROSS THE AFOREMENTIONED
AREAS. HRRR DOES REMOVE FOG NORTHWEST WHERE WE CURRENTLY HAVE
INCREASING UPPER CLOUDS AND WHERE WINDS WILL SHIFT TO SOUTHWEST
PROMOTING DRY AIR ADVECTION. WITH VISIBILITIES COMING UP AND DOWN
OPTING TO GO WITH A SPECIAL WEATHER STATEMENT FOR NOW HIGHLIGHTING
THE FOG VERSUS HEADLINES.
CHANCES FOR PRECIPITATION WILL CONTINUE TO MOVE EAST ACROSS THE
SOUTH NEAR THE COLD FRONTAL BOUNDARY TODAY INTO THE EVENING HOURS
WHEN FORCING ALOFT WILL BE PRESENT WITH THE UPPER JET. WILL
MENTION THUNDER POTENTIAL IN THE AFTERNOON AND EVENING WHEN
DAYTIME HEATING WILL RESULT IN DIURNAL INSTABILITY. FORCING
DECREASING LATER THIS EVENING SO WENT DRY OVERNIGHT. BREEZY ACROSS
THE NORTH TODAY NEAR THE UPPER LOW...SUB WIND ADVISORY MAGNITUDES.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 322 AM CDT FRI AUG 7 2015
THE MAIN FORECAST FOCUS IS ON THE POTENTIAL FOR PRECIPITATION ALONG
AND SOUTH OF I-94 THIS WEEKEND.
FAR SOUTHERN NORTH DAKOTA AND THE NORTHERN THIRD OF SOUTH DAKOTA ARE
THE CONSENSUS HOT SPOT FOR CONVECTION SATURDAY NIGHT AND
SUNDAY...ACCORDING TO THE 00 UTC GFS/ECMWF/GEFS/GEM GLOBAL
CONSENSUS. THUNDERSTORMS WILL LIKELY MOVE SLOWLY...BUT FLOOD RISK IS
LOW GIVEN LACK OF ANOMALOUS PRECIPITABLE WATER AND RECENT
DEMONSTRATION THAT SOILS CAN HANDLE OVER TWO INCHES PER HOUR WITHOUT
FLASH FLOODING.
IN ITS WAKE...THERE IS GENERAL CONSENSUS AMONG THE 00 UTC
GFS/ECMWF/GEFS/GEM GLOBAL SUITE THAT COMPLEX UPPER LEVEL FLOW WILL
EVOLVE INTO A SIMPLER WEST COAST TROUGH WITH AMPLIFIED RIDGING OVER
THE GREAT PLAINS BY MONDAY MORNING. ASSOCIATED BROAD SCALE
SUBSIDENCE SHOULD BE SUFFICIENT TO SQUELCH CONVECTION UNTIL AT LEAST
WEDNESDAY MORNING. UNCERTAINTY INCREASES THEREAFTER AS SEVERAL
ENSEMBLE MEMBERS EJECT SHORTWAVE ENERGY INTO EASTERN MONTANA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 618 AM CDT FRI AUG 7 2015
AREAS OF FOG ACROSS THE REGION WITH SHORT RANGE MODELS HINTING AT
FOG PERSISTING UNTIL 13-15Z. LIFR-VLIFR CIGS ALSO OCCURRING WITH THE
FOG. VFR FOR THE REMAINDER OF THE PERIOD.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SCHECK
SHORT TERM...NH
LONG TERM...SCHECK
AVIATION...NH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
351 AM CDT FRI AUG 7 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CDT FRI AUG 7 2015
FORECAST HIGHLIGHT IN THE SHORT TERM PERIOD IS FOG THIS MORNING.
CURRENTLY...ZONAL FLOW ALOFT WITH DEEP LOW PRESSURE OVER FAR
SOUTH CENTRAL CANADA AND RIDGING OVER THE SOUTHERN AND CENTRAL
PLAINS. BAND OF SHOWERS OVER SOUTHEAST MONTANA STRETCHING EASTWARD
INTO FAR SOUTHWEST NORTH DAKOTA ALONG A COLD FRONTAL BOUNDARY AND
UNDERNEATH AN UPPER JET. HIGH RES MODELS CONTINUE TO BRING THIS
PRECIPITATION INTO MY SOUTHWEST NOW THROUGH 10Z...SPREADING EAST
INTO MY SOUTH CENTRAL COUNTIES THROUGH THE AM HOURS. A FEW
LIGHTNING STRIKES BUT WILL KEEP THUNDER OUT OF THE MORNING
FORECAST WITH LITTLE TO NO CAPE ACROSS SOUTHERN NORTH DAKOTA.
AREAS OF FOG MAINLY OVER NORTHWESTERN...CENTRAL AND EASTERN
PORTIONS OF THE STATE. LATEST HRRR VISIBILITY OUTPUT INDICATES FOG
PERSISTING UNTIL 12-15Z THIS MORNING ACROSS THE AFOREMENTIONED
AREAS. HRRR DOES REMOVE FOG NORTHWEST WHERE WE CURRENTLY HAVE
INCREASING UPPER CLOUDS AND WHERE WINDS WILL SHIFT TO SOUTHWEST
PROMOTING DRY AIR ADVECTION. WITH VISIBILITIES COMING UP AND DOWN
OPTING TO GO WITH A SPECIAL WEATHER STATEMENT FOR NOW HIGHLIGHTING
THE FOG VERSUS HEADLINES.
CHANCES FOR PRECIPITATION WILL CONTINUE TO MOVE EAST ACROSS THE
SOUTH NEAR THE COLD FRONTAL BOUNDARY TODAY INTO THE EVENING HOURS
WHEN FORCING ALOFT WILL BE PRESENT WITH THE UPPER JET. WILL
MENTION THUNDER POTENTIAL IN THE AFTERNOON AND EVENING WHEN
DAYTIME HEATING WILL RESULT IN DIURNAL INSTABILITY. FORCING
DECREASING LATER THIS EVENING SO WENT DRY OVERNIGHT. BREEZY ACROSS
THE NORTH TODAY NEAR THE UPPER LOW...SUB WIND ADVISORY MAGNITUDES.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 322 AM CDT FRI AUG 7 2015
THE MAIN FORECAST FOCUS IS ON THE POTENTIAL FOR PRECIPITATION ALONG
AND SOUTH OF I-94 THIS WEEKEND.
FAR SOUTHERN NORTH DAKOTA AND THE NORTHERN THIRD OF SOUTH DAKOTA ARE
THE CONSENSUS HOT SPOT FOR CONVECTION SATURDAY NIGHT AND
SUNDAY...ACCORDING TO THE 00 UTC GFS/ECMWF/GEFS/GEM GLOBAL
CONSENSUS. THUNDERSTORMS WILL LIKELY MOVE SLOWLY...BUT FLOOD RISK IS
LOW GIVEN LACK OF ANOMALOUS PRECIPITABLE WATER AND RECENT
DEMONSTRATION THAT SOILS CAN HANDLE OVER TWO INCHES PER HOUR WITHOUT
FLASH FLOODING.
IN ITS WAKE...THERE IS GENERAL CONSENSUS AMONG THE 00 UTC
GFS/ECMWF/GEFS/GEM GLOBAL SUITE THAT COMPLEX UPPER LEVEL FLOW WILL
EVOLVE INTO A SIMPLER WEST COAST TROUGH WITH AMPLIFIED RIDGING OVER
THE GREAT PLAINS BY MONDAY MORNING. ASSOCIATED BROAD SCALE
SUBSIDENCE SHOULD BE SUFFICIENT TO SQUELCH CONVECTION UNTIL AT LEAST
WEDNESDAY MORNING. UNCERTAINTY INCREASES THEREAFTER AS SEVERAL
ENSEMBLE MEMBERS EJECT SHORTWAVE ENERGY INTO EASTERN MONTANA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 345 AM CDT FRI AUG 7 2015
AREAS OF FOG ACROSS THE REGION WITH SHORT RANGE MODELS HINTING AT
FOG PERSISTING UNTIL 13-15Z. HAVE ADDED FOG WORDING INTO ALL TAFS
WITH THE EXCEPTION OF KDIK. LIFR-VLIFR CIGS ALSO OCCURRING WITH
THE FOG. VFR FOR THE REMAINDER OF THE PERIOD.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...NH
LONG TERM...SCHECK
AVIATION...NH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
136 AM CDT FRI AUG 7 2015
.UPDATE...
ISSUED AT 136 AM CDT FRI AUG 7 2015
AREAS OF FOG DEVELOPING ACROSS MUCH OF WESTERN AND CENTRAL NORTH
DAKOTA THIS MORNING. THE EXCEPTION RIGHT NOW APPEARS TO BE THE
SOUTHWEST. A FEW OBSERVATION SITES HAVE COME IN AT A QUARTER MILE
OR LESS NORTHWEST AND AT KJMS. LATEST HRRR VISIBILITY OUTPUT
INDICATES FOG PERSISTING UNTIL 12-15Z THIS MORNING. AS WINDS
BECOME MORE SOUTHWEST ALONG TO SOUTH AND WEST OF THE
MISSOURI RIVER...VISIBILITIES SHOULD IMPROVE FOR THOSE LOCATIONS.
WILL CONTINUE TO MONITOR IN CASE A SPECIAL WEATHER STATEMENT OR
DENSE FOG ADVISORY BECOMES NEEDED.
OTHERWISE A MOSTLY CLEAR SKY AT THE MOMENT. INCREASING CLOUDS
SOUTHWEST AHEAD OF A BAND OF SHOWERS OVER SOUTHEAST MONTANA
STRETCHED ALONG A COLD FRONTAL BOUNDARY AND UNDERNEATH AN UPPER
JET. HIGH RES MODELS BRING THIS PRECIPITATION INTO MY SOUTHWEST
08-10Z...THEN SPREADS/CONTINUES THE LIGHT SHOWERS EAST ACROSS THE
SOUTHWEST INTO THE SOUTH CENTRAL THROUGH THE AM HOURS. KEPT
THUNDER OUT FOR NOW WITH ONLY ONE LIGHTNING STRIKE THE PAST HOUR
OR TWO AND NOT MUCH CAPE TO WORK WITH OVER HERE.
UPDATE ISSUED AT 928 PM CDT THU AUG 6 2015
ISOLATED THUNDERSTORMS FORMING ALONG A COLD FRONT ACROSS
NORTHWEST NORTH DAKOTA IN DIVIDE COUNTY. THIS MAY LAST A FEW
HOURS..AT LEAST THROUGH MIDNIGHT. FOLLOWING THE FRONT INTO
MONTANA THERE APPEARS TO BE SOME SUPPORT FROM THE H300 JET FOR
SOME SHOWERS LATE TONIGHT SOUTHWEST. ADDED SLIGHT CHANCE ALONG THE
NORTHWEST CANADIAN BORDER TONIGHT AND ALONG THE SOUTHWEST SOUTH
DAKOTA BORDER LATE AS WELL. HRRR SUGGESTS SOME PATCHY FOG TONIGHT
CENTRAL AND EAST. ADDED FOG AFTER MIDNIGHT.
UPDATE ISSUED AT 737 PM CDT THU AUG 6 2015
RADAR AND SATELLITE DATA SHOW THE MAIN AREA OF PRECIPITATION IS
EXITING THE REGION. WILL CANCEL THE FLASH FLOOD WATCH. THIS WILL
END THE PRECIPITATION FOR TONIGHT EAST.
COLD FRONT ASSOCIATED WITH THE MAIN LOW LAGS BACK IN EASTERN
MONTANA. WITH LIMITED SUPPORT ALOFT WILL NOT ADD POPS TO THE
SOUTHWEST AT THIS TIME. BUT ACROSS THE NORTHWEST A BAND OF
SHOWERS AND ISOLATED THUNDERSTORMS MAY LINGER THROUGH THE EVENING
ACROSS THE NORTHWEST. WILL WATCH THE HRRR TRENDS FOR THE AFTER
MIDNIGHT PERIOD.
UPDATE ISSUED AT 534 PM CDT THU AUG 6 2015
CANCELED THE FLASH FLOOD WATCH FOR ALL BUT THE JAMES RIVER
VALLEY.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 250 PM CDT THU AUG 6 2015
HEAVY RAINFALL POTENTIAL THROUGH EARLY THIS EVENING SOUTH CENTRAL
AND INTO THE JAMES RIVER VALLEY HIGHLIGHTS THE SHORT TERM
FORECAST.
THE FLASH FLOOD WATCH FOR THE SOUTH CENTRAL AND JAMES RIVER VALLEY
REMAINS IN EFFECT UNTIL 10 PM CDT THIS EVENING. RADAR TRENDS
THROUGH 20 UTC DEPICT NUMEROUS SLOWING MOVING...WARM RAIN PROCESS
DOMINATED STORMS ACROSS THE AFOREMENTIONED AREAS. GIVEN TRENDS IN
THE 17-19 UTC HRRR ITERATIONS WHICH HAVE OVERALL HANDLED THE EVENT
WELL...EXPECT ACTIVITY TO BEGIN TO WANE/PROPAGATE EAST INTO THE
RED RIVER VALLEY BY 23-00 UTC. FURTHER WEST NEAR THE OCCLUDED
FRONTAL BOUNDARY FROM NORTHEAST MONTANA THROUGH LAKE
OAHE...DIURNALLY DRIVEN ISOLATED CONVECTION IS EXPECTED.
HOWEVER...SEVERE WEATHER IS NOT ANTICIPATED.
GIVEN GOOD AGREEMENT ON THE 12 UTC DETERMINISTIC SUITE...A DRY
COLD FRONTAL PASSAGE IS EXPECTED ON FRIDAY...WITH SEASONABLE
TEMPERATURES AND MOSTLY SUNNY SKIES.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 250 PM CDT THU AUG 6 2015
A POTENTIAL WARM UP NEXT WEEK HIGHLIGHTS THE EXTENDED FORECAST.
THE 12 UTC GUIDANCE SUITE IS IN AGREEMENT ON QUASI-ZONAL THIS
WEEKEND AMPLIFYING EARLY NEXT WEEK AS AN INTERMOUNTAIN
WEST/CENTRAL CONUS UPPER LEVEL RIDGE BUILDS. THIS SUPPORTS A
POSSIBLE TRANSITION FROM NEAR NORMAL TEMPERATURES THIS
WEEKEND...WARMING THROUGH NEXT WEEK. GIVEN WEAK WAVES EMBEDDED IN THE
FAST QUASI-ZONAL FLOW THIS WEEKEND...DAILY CHANCES FOR
THUNDERSTORMS ARE FORECAST SATURDAY AND SUNDAY GENERALLY SOUTH OF
ND HIGHWAY 200. SEVERE THUNDERSTORMS ARE NOT EXPECTED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 136 AM CDT FRI AUG 7 2015
AREAS OF FOG DEVELOPING ACROSS THE REGION WITH SHORT RANGE MODELS
HINTING AT FOG PERSISTING UNTIL 13-15Z. HAVE ADDED FOG WORDING
INTO ALL TAFS WITH THE EXCEPTION OF KDIK. LIFR-VLIFR CIGS ALSO
OCCURRING WITH THE FOG.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...AYD
LONG TERM...AYD
AVIATION...NH
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1029 PM EDT SAT AUG 8 2015
.SYNOPSIS...
WEAK FLOW THROUGH THE WEEKEND. LOW PRESSURE SYSTEM CROSSES MONDAY
INTO MONDAY NIGHT. MID/UPPER LEVEL TROF AXIS PASSES TUESDAY.
&&
.NEAR TERM /THROUGH SUNDAY/...
UPDATE...
FORECAST ON TRACK THIS EVENING.
PREVIOUS DISCUSSION...
A WEAK FLOW REMAINS OVER THE REGION THROUGH THE WEEKEND. MESO MODELS
SHOWING THAT THERE COULD BE ENOUGH MOISTURE TO FIRE SOME
SHOWERS/THUNDERSTORMS THIS AFTERNOON AND EVENING IN SOUTHEAST
OHIO...NORTHERN WV...AND THE WV MOUNTAINS...WITH THE BEST CHANCES IN
NORTHEASTERN WV.
SHOULD SEE DECENT RADIATION CONDITIONS TONIGHT...ALLOWING FOR
TEMPERATURES TO BOTTOM OUT A BIT BELOW THE DEW POINTS. EXPECT SOME
VALLEY FOG TO FORM LATE TONIGHT.
MODELS ARE A BIT MORE QUESTIONABLE WITH THE MOISTURE ON SUNDAY
AFTERNOON. WILL KEEP A SMALL POP IN NORTHEASTERN WV...AND ADD A
SMALL POP TO THE WESTERN COUNTIES DUE TO GFS.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
A DEVELOPING WARM FRONT SHOULD PROVIDE THE FOCUS FOR SCT SHRA/TSRA
TOWARD MONDAY MORNING. WITH DAYTIME HEATING EXPECT THE COVERAGE TO
INCREASE MONDAY AFTERNOON ACROSS THE N. A STRONG COLD FRONT WILL
SWEEP THRU MONDAY NIGHT. HOWEVER...ENOUGH LOW LEVEL MOISTURE WILL
REMAIN FOR TUESDAY FOR SCT SHRA MOVE ACROSS AS THE UPPER TROF
SETTLES IN. THINK MOST OF THIS WOULD BE CONFINED TO THE MOUNTAINS
BY THE AFTERNOON.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
A FRESH AIRMASS WILL SETTLE IN FOR THE EXTENDED WITH MILD
COMFORTABLE DAYS AND COOL NIGHTS. SOME MODERATION OVER THE
WEEKEND.
&&
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
EXPECTING MORE CLOUD COVER TONIGHT WHICH SHOULD PRECLUDE FOG
DEVELOPMENT OVERNIGHT. THE SOURCE FOR THIS CLOUD COVER WILL BE
UPPER LEVEL DISTURBANCES IN THE NORTHWEST FLOW ALOFT. GUIDANCE IS
ONCE AGAIN VERY PESSIMISTIC WITH LIFR VALLEY FOG IN THE
FORECAST...BUT WILL GO CONSERVATIVE...EVEN MORE SO THAN LAST
NIGHT. WILL KEEP ALL SITES VFR FOR NOW GIVEN THE RAP CLOUD COVER
FORECAST WHICH HAS 50-70 PERCENT SKY COVER THROUGH 12Z.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z MONDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: CLOUD COVER/FOG VARIABILITY TONIGHT COULD
REQUIRE AMENDMENTS.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE SUN 08/09/15
UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11
EDT 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H H H H H H H H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 00Z MONDAY...
IFR POSSIBLE IN SHOWERS AND THUNDERSTORMS MONDAY AND MONDAY
NIGHT...THEN IN LINGERING LOW CEILINGS IN THE WAKE OF THE PCPN
TUESDAY MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...RPY/30
NEAR TERM...RPY/26
SHORT TERM...30
LONG TERM...30
AVIATION...26
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
724 PM EDT SAT AUG 8 2015
.SYNOPSIS...
WEAK FLOW THROUGH THE WEEKEND. LOW PRESSURE SYSTEM CROSSES MONDAY
INTO MONDAY NIGHT. MID/UPPER LEVEL TROF AXIS PASSES TUESDAY.
&&
.NEAR TERM /THROUGH SUNDAY/...
UPDATE...
NO MAJOR CHANGES THIS EVENING EXCEPT FOR AN INCREASE IN SKY COVER
TONIGHT PER THE RAP AND SATELLITE TRENDS.
PREVIOUS DISCUSSION...
A WEAK FLOW REMAINS OVER THE REGION THROUGH THE WEEKEND. MESO MODELS
SHOWING THAT THERE COULD BE ENOUGH MOISTURE TO FIRE SOME
SHOWERS/THUNDERSTORMS THIS AFTERNOON AND EVENING IN SOUTHEAST
OHIO...NORTHERN WV...AND THE WV MOUNTAINS...WITH THE BEST CHANCES IN
NORTHEASTERN WV.
SHOULD SEE DECENT RADIATION CONDITIONS TONIGHT...ALLOWING FOR
TEMPERATURES TO BOTTOM OUT A BIT BELOW THE DEW POINTS. EXPECT SOME
VALLEY FOG TO FORM LATE TONIGHT.
MODELS ARE A BIT MORE QUESTIONABLE WITH THE MOISTURE ON SUNDAY
AFTERNOON. WILL KEEP A SMALL POP IN NORTHEASTERN WV...AND ADD A
SMALL POP TO THE WESTERN COUNTIES DUE TO GFS.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
A DEVELOPING WARM FRONT SHOULD PROVIDE THE FOCUS FOR SCT SHRA/TSRA
TOWARD MONDAY MORNING. WITH DAYTIME HEATING EXPECT THE COVERAGE TO
INCREASE MONDAY AFTERNOON ACROSS THE N. A STRONG COLD FRONT WILL
SWEEP THRU MONDAY NIGHT. HOWEVER...ENOUGH LOW LEVEL MOISTURE WILL
REMAIN FOR TUESDAY FOR SCT SHRA MOVE ACROSS AS THE UPPER TROF
SETTLES IN. THINK MOST OF THIS WOULD BE CONFINED TO THE MOUNTAINS
BY THE AFTERNOON.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
A FRESH AIRMASS WILL SETTLE IN FOR THE EXTENDED WITH MILD
COMFORTABLE DAYS AND COOL NIGHTS. SOME MODERATION OVER THE
WEEKEND.
&&
.AVIATION /23Z SATURDAY THROUGH THURSDAY/...
EXPECTING MORE CLOUD COVER TONIGHT WHICH SHOULD PRECLUDE FOG
DEVELOPMENT OVERNIGHT. THE SOURCE FOR THIS CLOUD COVER WILL BE
UPPER LEVEL DISTURBANCES IN THE NORTHWEST FLOW ALOFT. GUIDANCE IS
ONCE AGAIN VERY PESSIMISTIC WITH LIFR VALLEY FOG IN THE
FORECAST...BUT WILL GO CONSERVATIVE...EVEN MORE SO THAN LAST
NIGHT. WILL KEEP ALL SITES VFR FOR NOW GIVEN THE RAP CLOUD COVER
FORECAST WHICH HAS 50-70 PERCENT SKY COVER THROUGH 12Z.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z MONDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: CLOUD COVER/FOG VARIABILITY TONIGHT COULD
REQUIRE AMENDMENTS.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 21 22 23 00 01 02 03 04 05 06 07 08
EDT 1HRLY 17 18 19 20 21 22 23 00 01 02 03 04
CRW CONSISTENCY H H H H H H H H H H M M
HTS CONSISTENCY H H H H H H H H H H M M
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H H H H H H H H M M
PKB CONSISTENCY H H H H H H H H H H M M
CKB CONSISTENCY H H H H H H H H H H M M
AFTER 00Z MONDAY...
IFR POSSIBLE IN SHOWERS AND THUNDERSTORMS MONDAY AND MONDAY
NIGHT...THEN IN LINGERING LOW CEILINGS IN THE WAKE OF THE PCPN
TUESDAY MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...RPY/30
NEAR TERM...RPY/26
SHORT TERM...30
LONG TERM...30
AVIATION...26
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
650 PM CDT SAT AUG 8 2015
.AVIATION...
THE MAIN AVIATION CONCERN IS THE POTENTIAL FOR ISOLATED HIGH-BASED
T-STORM ACTIVITY TO APPROACH KLBB AND KPVW FROM THE WEST THIS
EVENING. THE MAIN THREATS FROM THIS ACTIVITY WILL BE
STRONG...ERRATIC WIND GUSTS AND LIGHTNING. CONFIDENCE IS TOO LOW
AT THIS TIME TO INCLUDE A TEMPO GROUP IN THE TAFS. OTHERWISE...VFR
CONDITIONS ARE EXPECTED WITH PERHAPS A LOW THREAT OF T-STORMS
AGAIN VERY LATE IN THE FORECAST PERIOD.
&&
.PREV DISCUSSION... /ISSUED 625 PM CDT SAT AUG 8 2015/
UPDATE...
SCATTERED THUNDERSTORMS HAVE DEVELOPED ACROSS EAST-CENTRAL NEW
MEXICO AND APPEAR POISED TO AFFECT THE FAR SOUTHWEST TEXAS
PANHANDLE AND PERHAPS THE EXTREME NORTHWESTERN SOUTH PLAINS.
GIVEN THIS WE HAVE INCREASED POPS CONSIDERABLY FOR OUR FAR
NORTHWESTERN ZONES THIS EVENING. THE REMAINDER OF THE FORECAST
REMAINS IN GOOD SHAPE AND NO OTHER ADJUSTMENTS WERE MADE ATTM.
PREV DISCUSSION... /ISSUED 234 PM CDT SAT AUG 8 2015/
SHORT TERM...
BIGGEST CHANGE FROM EARLIER FORECASTS WAS TO EXPAND ISOLATED STORM
MENTION EASTWARD ACROSS MUCH OF THE CAPROCK THIS EVENING. EARLY
AFTERNOON ANALYSIS INDICATES A FAVORABLE COLLOCATION OF SURFACE
TROUGHING AND STEEP MID-LEVEL LAPSE RATES JUST WEST OF THE TX-NM
BORDER. SURFACE DEWPOINTS AREA WIDE ARE RUNNING 5-15 DEGS HIGHER
THAN THIS TIME YESTERDAY AND ARE YIELDING 1000-2000 J/KG OF MLCAPE
ACROSS THE SOUTH PLAINS. ALREADY NOTICING SOME CU BUILDING SOUTH OF
CVS AT 19Z AS DEEP MIXING THERE CATAPULTS PARCELS TO THEIR CCL
LEVELS. THIS THEME SHOULD EXPAND SOUTHWARD ALONG THE SURFACE TROUGH
WITH A FEW STORMS LIKELY TO BE DOTTING OUR WESTERN ZONES BY LATE
AFTERNOON. AS THESE PULSE-TYPE CELLS MOVE SLOWLY NORTHEAST...OUTFLOW
REGENERATION OF NEW STORMS SEEMS PLAUSIBLE THROUGH EARLY EVENING IN
LIGHT OF MEAGER CIN. HRRR HAS BEEN QUITE ADAMANT IN BLOSSOMING A
LARGER COVERAGE OF STORMS BEFORE SUNSET...BUT WITH NO DISCERNIBLE
BACKGROUND SUPPORT AVAILABLE IT SEEMS A SAFER BET TO KEEP PRECIP
MENTION ON THE ISOLATED SIDE. A DECENT NOCTURNAL LLJ MAY KEEP SOME
SEMBLANCE OF THESE EARLIER STORMS INTACT AFTER MIDNIGHT.
SUNDAY WILL SEE A TALL AND CLOSED ANTICYCLONE RETROGRADE TO CENTRAL
TEXAS COMPLETE WITH RISING HEIGHTS AND THICKNESSES LOCALLY. THIS
PROCESS WILL HELP REORIENT THE SURFACE TROUGH FROM N-S TO NE-SW
ACROSS THE WRN TX PANHANDLE INTO ERN NM. BEST STORM CHANCES SHOULD
PLAY OUT IN THE NRN PANHANDLE NEAR THE INTERSECTION OF THE TROUGH
AND A STALLING FRONT...BUT DEEP MIXING AND WEAK CAPE IN OUR NW
COUNTIES COULD SPUR A FEW LATE AFTERNOON STORMS. OTHERWISE...MAX
TEMPS LOOK TO SHAKE OUT A DEGREE OR TWO WARMER THAN TODAY.
LONG TERM...
UPPER LEVEL RIDGE IS EXPECTED TO BE CENTERED OVER EAST
TEXAS SUNDAY EVENING WHILST VIGOROUS UPPER LEVEL LOW SLIDES DOWN THE
COAST OF BRITISH COLUMBIA. THE STRENGTH OF THE RIDGE IS EXPECTED TO
BE SUFFICIENTLY STRONG TO HOLD THE LOW OFF THE PACIFIC NORTHWEST
COAST AT LEAST THROUGH 120 HOURS BEFORE IT EJECTS NEWRD INTO SRN
CANADA. TO OUR NORTH A SHORTWAVE PASSES EARLY MONDAY ACROSS THE
CENTRAL PLAINS FOLLOWED BY ANOTHER SURGE OF ENERGY ROTATING ABOUT
HUDSON BAY LOW EARLY TUESDAY BEFORE RIDGE BUILDS STRONGLY ALL THE
WAY UP TO NUNAVUT. AS THE HIGH SLOWLY RETROGRADES...FLOW WILL
BECOME MORE NORTHERLY TO NORTHEASTERLY WITH TIME AND THIS SHOULD
HELP COOL TEMPS A BIT IN THE LATTER EXTENDED.
BEST RAIN CHANCES DURING THE EXTENDED WILL EXIST FROM SUNDAY EVENING
INTO TUESDAY AS FRONTAL BOUNDARY SAGS INTO THE REGION. HIGHEST
POTENTIAL WILL EXIST NORTH AND WEST. TRENDS HAVE BEEN EDGING THE
BOUNDARY FURTHER SOUTH WITH EACH RUN AND THIS CERTAINLY FITS THE
PATTERN THIS SUMMER. THINGS LOOK TO DRY OUT ON WEDNESDAY WITH
PERHAPS A FEW SCT SHOWERS NEAR THE ESCARPMENT BUT OVERALL TRENDING
DRIER FOR THE REMAINDER OF THE EXTENDED.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 64 94 67 90 / 50 20 20 30
TULIA 66 95 68 92 / 20 0 20 30
PLAINVIEW 65 95 70 93 / 20 0 10 20
LEVELLAND 68 96 70 95 / 20 0 10 20
LUBBOCK 71 98 72 96 / 20 0 10 10
DENVER CITY 68 98 69 96 / 20 0 10 10
BROWNFIELD 68 98 70 96 / 20 0 10 10
CHILDRESS 73 102 75 99 / 0 0 10 20
SPUR 70 101 72 99 / 0 0 10 0
ASPERMONT 75 104 75 103 / 0 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
33/23
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
625 PM CDT SAT AUG 8 2015
.UPDATE...
SCATTERED THUNDERSTORMS HAVE DEVELOPED ACROSS EAST-CENTRAL NEW
MEXICO AND APPEAR POISED TO AFFECT THE FAR SOUTHWEST TEXAS
PANHANDLE AND PERHAPS THE EXTREME NORTHWESTERN SOUTH PLAINS.
GIVEN THIS WE HAVE INCREASED POPS CONSIDERABLY FOR OUR FAR
NORTHWESTERN ZONES THIS EVENING. THE REMAINDER OF THE FORECAST
REMAINS IN GOOD SHAPE AND NO OTHER ADJUSTMENTS WERE MADE ATTM.
&&
.PREV DISCUSSION... /ISSUED 234 PM CDT SAT AUG 8 2015/
SHORT TERM...
BIGGEST CHANGE FROM EARLIER FORECASTS WAS TO EXPAND ISOLATED STORM
MENTION EASTWARD ACROSS MUCH OF THE CAPROCK THIS EVENING. EARLY
AFTERNOON ANALYSIS INDICATES A FAVORABLE COLLOCATION OF SURFACE
TROUGHING AND STEEP MID-LEVEL LAPSE RATES JUST WEST OF THE TX-NM
BORDER. SURFACE DEWPOINTS AREA WIDE ARE RUNNING 5-15 DEGS HIGHER
THAN THIS TIME YESTERDAY AND ARE YIELDING 1000-2000 J/KG OF MLCAPE
ACROSS THE SOUTH PLAINS. ALREADY NOTICING SOME CU BUILDING SOUTH OF
CVS AT 19Z AS DEEP MIXING THERE CATAPULTS PARCELS TO THEIR CCL
LEVELS. THIS THEME SHOULD EXPAND SOUTHWARD ALONG THE SURFACE TROUGH
WITH A FEW STORMS LIKELY TO BE DOTTING OUR WESTERN ZONES BY LATE
AFTERNOON. AS THESE PULSE-TYPE CELLS MOVE SLOWLY NORTHEAST...OUTFLOW
REGENERATION OF NEW STORMS SEEMS PLAUSIBLE THROUGH EARLY EVENING IN
LIGHT OF MEAGER CIN. HRRR HAS BEEN QUITE ADAMANT IN BLOSSOMING A
LARGER COVERAGE OF STORMS BEFORE SUNSET...BUT WITH NO DISCERNIBLE
BACKGROUND SUPPORT AVAILABLE IT SEEMS A SAFER BET TO KEEP PRECIP
MENTION ON THE ISOLATED SIDE. A DECENT NOCTURNAL LLJ MAY KEEP SOME
SEMBLANCE OF THESE EARLIER STORMS INTACT AFTER MIDNIGHT.
SUNDAY WILL SEE A TALL AND CLOSED ANTICYCLONE RETROGRADE TO CENTRAL
TEXAS COMPLETE WITH RISING HEIGHTS AND THICKNESSES LOCALLY. THIS
PROCESS WILL HELP REORIENT THE SURFACE TROUGH FROM N-S TO NE-SW
ACROSS THE WRN TX PANHANDLE INTO ERN NM. BEST STORM CHANCES SHOULD
PLAY OUT IN THE NRN PANHANDLE NEAR THE INTERSECTION OF THE TROUGH
AND A STALLING FRONT...BUT DEEP MIXING AND WEAK CAPE IN OUR NW
COUNTIES COULD SPUR A FEW LATE AFTERNOON STORMS. OTHERWISE...MAX
TEMPS LOOK TO SHAKE OUT A DEGREE OR TWO WARMER THAN TODAY.
LONG TERM...
UPPER LEVEL RIDGE IS EXPECTED TO BE CENTERED OVER EAST
TEXAS SUNDAY EVENING WHILST VIGOROUS UPPER LEVEL LOW SLIDES DOWN THE
COAST OF BRITISH COLUMBIA. THE STRENGTH OF THE RIDGE IS EXPECTED TO
BE SUFFICIENTLY STRONG TO HOLD THE LOW OFF THE PACIFIC NORTHWEST
COAST AT LEAST THROUGH 120 HOURS BEFORE IT EJECTS NEWRD INTO SRN
CANADA. TO OUR NORTH A SHORTWAVE PASSES EARLY MONDAY ACROSS THE
CENTRAL PLAINS FOLLOWED BY ANOTHER SURGE OF ENERGY ROTATING ABOUT
HUDSON BAY LOW EARLY TUESDAY BEFORE RIDGE BUILDS STRONGLY ALL THE
WAY UP TO NUNAVUT. AS THE HIGH SLOWLY RETROGRADES...FLOW WILL
BECOME MORE NORTHERLY TO NORTHEASTERLY WITH TIME AND THIS SHOULD
HELP COOL TEMPS A BIT IN THE LATTER EXTENDED.
BEST RAIN CHANCES DURING THE EXTENDED WILL EXIST FROM SUNDAY EVENING
INTO TUESDAY AS FRONTAL BOUNDARY SAGS INTO THE REGION. HIGHEST
POTENTIAL WILL EXIST NORTH AND WEST. TRENDS HAVE BEEN EDGING THE
BOUNDARY FURTHER SOUTH WITH EACH RUN AND THIS CERTAINLY FITS THE
PATTERN THIS SUMMER. THINGS LOOK TO DRY OUT ON WEDNESDAY WITH
PERHAPS A FEW SCT SHOWERS NEAR THE ESCARPMENT BUT OVERALL TRENDING
DRIER FOR THE REMAINDER OF THE EXTENDED.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 64 94 67 90 / 50 20 20 30
TULIA 66 95 68 92 / 20 0 20 30
PLAINVIEW 65 95 70 93 / 20 0 10 20
LEVELLAND 68 96 70 95 / 20 0 10 20
LUBBOCK 71 98 72 96 / 20 0 10 10
DENVER CITY 68 98 69 96 / 20 0 10 10
BROWNFIELD 68 98 70 96 / 20 0 10 10
CHILDRESS 73 102 75 99 / 0 0 10 20
SPUR 70 101 72 99 / 0 0 10 0
ASPERMONT 75 104 75 103 / 0 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
33/23
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
942 PM EDT SAT AUG 8 2015
.SYNOPSIS...
WEAK HIGH PRESSURE WILL MOVE OVERHEAD SUNDAY. RAIN CHANCES WILL
INCREASE MONDAY INTO MONDAY NIGHT AS A COMPLEX FRONTAL SYSTEM
MOVES INTO THE REGION. A COLD FRONT WILL SWEEP ACROSS THE AREA
TUESDAY FOLLOWED BY HIGH PRESSURE THAT BRING ANOTHER ROUND OF
DRIER AND COOLER WEATHER FOR MID AND LATE WEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
AS OF 940 PM EDT SATURDAY...
PERSISTENT AREA OF SHOWERS CONTINUE TO IMPACT CENTRAL PART OF FCST
AREA FROM NEAR WV/VA BORDER INTO NEW RIVER VALLEY AND MAY REACH
TO NEAR BLUE RIDGE OF FAR SW VA BY 11PM BEFORE LIKELY DISSIPATING
BY AROUND MIDNIGHT. LATEST HRRR RUN ACTUALLY NOW HAS PRETTY GOOD
HANDLE ON CURRENT RADAR DEPICTION AND DOES SHOW STEADY
WEAKENING...EXCEPT FOR AROUND THE BLUE RIDGE OF FAR SW VA AND NW
NC WELL AFTER MIDNIGHT. HAVE ONCE AGAIN EXTENDED SOME SLIGHT CHC
POPS A LITTLE LATER INTO THE OVERNIGHT BUT STILL REMOVING
COMPLETELY BY 07Z AS STILL FEEL THAT WITH NEGLIBLE INSTABILITY BY
THAT TIME THAT NAM AND SOME OTHER HI RES MODELS ARE OVERDOING IT
PERHAPS DUE TO A WEAK S/WV IN NW FLOW COMING FROM OHIO VALLEY THAT
NOT SURE IS EVEN REALLY THERE. REDUCED SKY COVER ON THE SW AND SE
FRINGES BUT LEFT MOSTLY CLOUDY IN THE MIDDLE OVERNIGHT WITH THE
WEAK LOW LEVEL CONVERGENCE NEAR BLUE RIDGE. KEPT PATCHY FOG BUT A
FORMING A BIT LATER. OTHERWISE TEMPS OVERNIGHT LOOK GOOD SO NO
OTHER CHANGES.
PREV DISCUSSION AS OF 655 PM EDT SATURDAY...
ISOLATED SHOWERS CONTINUE TO SLOWLY DRIFT SOUTHEASTWARD ACROSS
ALLEGHENY HIGHLANDS INTO SOUTHERN SHENANDOAH VALLEY AND IN A FEW
OTHER SPOTS ACROSS SOUTHEAST WV AND MTNS OF SW VA AND FAR NW NC.
HAVE NOT OBSERVED ANY IN-CLOUD OR CLOUD-TO-GROUND LIGHTNING SO
FAR THIS AFT AND EARLY EVE. WHILE HI RES MODELS LIKE HRRR...AS
WELL AS 18Z NAM...TRY TO LINGER THESE UNTIL MIDNIGHT OR EVEN
BEYOND...DO NOT SEE SIGNIFICANT MECHANISM ONCE WE LOSE HEATING TO
KEEP THESE GOING...OTHER THAN SOME WEAK LOW-LEVEL CONVERGENCE NEAR
THE BLUE RIDGE WHICH MAY BE ENOUGH TO EXTEND A FEW MORE HOURS PAST
SUNSET BUT NOT ALL THAT CONFIDENT. INSTABILITY REMAINS QUITE LOW
AND CONFINED MAINLY TO THE WESTERN SLOPES SO AS THESE MOVE FARTHER
EAST THEY SHOULD SLOWLY DIE. NEVERTHELESS...HAVE STRETCHED THE
15-20 POP AREA JUST EAST OF THE BLUE RIDGE AND EXTENDED IN TIME
UNTIL ABOUT MIDNIGHT PER THESE MODELS...BUT NOT READY TO GO BEYOND
THAT YET. OTHERWISE OTHER THAN A FEW NUDGES TO TEMPS, DEW PTS AND
SKY COVER PER LATEST OBSERVATIONS...NOT OTHER CHANGES THROUGH THE
OVERNIGHT.
PREV DISCUSSION AS OF 222 PM EDT SATURDAY...
LOCAL WRF/HRRR ISOLATED TO WIDELY SCATTERED SHOWERS FROM THE
ALLEGHANY HIGHLANDS WV/VA SOUTHWARD TO THE VA FOOTHILLS THROUGH
EARLY EVENING BEFORE DISSIPATING. MAY SEE A FEW SHOWER SOUTHWEST
TOWARD THE MTNS OF NC/FAR SW VA AS WELL CLOSER TO HIGHER THETA-E
AIR. STILL NOT MUCH OUT THERE...AND EVEN THREAT OF THUNDERSTORMS IS
LOW WITH MARGINAL CAPE.
OVERNIGHT HAVE INCREASED CLOUD COVER AS THINK WE WILL SEE AN
INVERSION SET UP WITH LITTLE TO NIL MIXING AND ANY LINGERING
STRATOCU/CU WILL SPREAD OUT THROUGH THE NIGHT. NOT COMPLETELY CLOUDY
SO NOT OUT OF THE QUESTION TO SEE FOG FORM IN THE VALLEYS OVERNIGHT.
LOWS WILL STAY CLOSE TO SEASONAL NORMS OF LOW TO MID 60S.
SUNDAY...THE 5H RIDGE AND HEIGHTS BUILD A LITTLE TO THE NORTHEAST.
WEAK UPPER SUPPORT TO COMBINE WITH LOW LEVEL THETA-E RIDGE OVER THE
BLUE RIDGE TO FORM A FEW SHOWERS/ISOLATED STORMS IN THE AFTERNOON.
SKIES WILL BE MOSTLY SUNNY OVER THE PIEDMONT...TO PARTLY
SUNNY...BECOMING MOSTLY CLOUDY WEST. HIGHS TO RANGE FROM THE UPPER
70S TO LOWER 80S IN THE MOUNTAINS...TO MID TO UPPER 80S EAST.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
AS OF 330 PM SATURDAY...
SIMILAR TO PAST FEW EVENINGS...ONGOING SHOWERS AND THUNDERSTORMS
SUNDAY WILL DIMINISH BEFORE MIDNIGHT.
FORCING WILL BE A COMBINATION OF WARM AIR ADVECTION AND OVERRUNNING
ACROSS THE WARM FRONT AND LIFT AHEAD OF THE COLD FRONT MONDAY NIGHT
AND TUESDAY MORNING. THE MOST UNSTABLE AIR WILL BE JUST ALONG THE
FRONT SO STRONG THUNDERSTORMS ARE STILL POSSIBLE IN THE EASTERN
COUNTY WARNING AREA TUESDAY AFTERNOON BUT THIS IS HEAVILY DEPENDENT
ON THE SPEED OF THE FRONT. DEEP MOISTURE WITH PRECIPITABLE WATER
VALUES JUST UNDER 2.0 INCHES WILL FILL IN ACROSS THE FORECAST AREA
ON SUNDAY NIGHT.
USED WARMER GUIDANCE FOR MINIMUM TEMPERATURES ON SUNDAY NIGHT SINCE
DEW POINTS WILL BE INCREASING. CLOUDS AND PRECIPITATION WILL LIMIT
TEMPERATURE RISE ON MONDAY. HAVE TRIMMED BACK MAXIMUM TEMPERATURES.
FORECAST AREA WILL STILL BE AHEAD OF THE COLD FRONT ON MONDAY NIGHT
SO TEMPERATURES WILL REMAIN MILD. MAV GUIDANCE LOOKS REASONABLE FOR
MONDAY NIGHT LOWS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 200 PM SATURDAY...
CLOSED 500 MB LOW OVER SOUTHEAST CANADA BY TUESDAY NIGHT AND A DEEP
TROF REMAINS OVER THE EAST THROUGH THURSDAY. BY FRIDAY THERE IS
STILL TROUGHING OVER THE EASTERN UNITED STATES BUT THE UPPER LOW HAS
RETREATED NORTH AND HEIGHTS ARE HIGHER OVER THE MID ATLANTIC STATES.
THERE MAY BE ENOUGH VORTICITY ROTATING AROUND THE UPPER LOW ON
WEDNESDAY TO PROVIDE SOME LIFT TO THE MOUNTAINS IN SOUTHEAST WEST
VIRGINIA.
SURFACE HIGH PRESSURE OVER THE MISSISSIPPI VALLEY ON TUESDAY NIGHT
WILL GRADUALLY BUILD EAST. BY FRIDAY MORNING AT LEAST A PIECE OF THE
HIGH WILL BE CENTERED OVER THE FORECAST AREA. THE HIGH STAYS IN THE
REGION THROUGH THE WEEKEND.
ECMWF HAS BEEN PERSISTENT LAST FEW DAYS BRINGING COOLER AND DRIER
AIR MASS INTO THE FORECAST AREA WITH 850 MB TEMPERATURES IN +10 TO
+12 RANGE BY THURSDAY MORNING. THEN AIR MASS MODERATES ON FRIDAY AND
SATURDAY WITH NEAR NORMAL TEMPERATURES.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
AS OF 720 PM EDT SATURDAY...
VFR CONDITIONS PREVAIL ACROSS THE REGION CURRENTLY WITH ISOLATED
TO SCATTERED SHOWERS MAINLY WITHIN A REGION BOUNDED TO THE RIGHT
OF A KLWB-KLYH-KBCB-KLWB LINE. WILL HAVE VCSH MENTIONED AT EACH OF
THESE TERMINALS THROUGH 03Z/11PM TO ACCOUNT FOR THE ACTIVITY.
WHILE NO PREVAILING WEATHER IS FORECAST AT THIS TIME...KBCB MAY BE
THE SITE OF THE THREE TWO WATCH FOR POSSIBLE AMENDMENTS TO THE
CONTRARY.
THROUGH THE OVERNIGHT...STRATOCUMULUS CLOUD COVER IS EXPECTED TO
REDEVELOP ACROSS THE REGION BELOW THE NOCTURNAL INVERSION. THIS
WOULD PLACE LOW END VFR CLOUDS EAST OF THE BLUE RIDGE WITH MVFR
ACROSS THE MOUNTAINS. PATCHY MIST WILL REDUCE VISIBILITIES TO MVFR
LEVELS MAINLY WITHIN SOME THE MOUNTAIN AND RIVER VALLEYS.
ANY SUB-VFR CONDITIONS ARE EXPECTED TO IMPROVE TO VFR BY
15-16Z/11AM-NOON ON SUNDAY. ADDITIONAL ISOLATED TO SCATTERED
AFTERNOON SHOWERS ARE EXPECTED ON SUNDAY...ESPECIALLY ACROSS THE
MOUNTAINS.
EXTENDED AVIATION DISCUSSION...
AS OF 125 PM EDT SATURDAY...
MONDAY INTO TUESDAY...SHOWERS AND STORMS INCREASE AGAIN ACROSS THE
REGION THANKS TO BOTH A FRONTAL BOUNDARY ENTERING THE REGION AND A
SHORTWAVE TROUGH PROGRESSING EASTWARD THROUGH THE OHIO VALLEY.
MAINLY VFR CONDITIONS ARE EXPECTED EXCEPT SUB-VFR CONDITIONS
WHERE CONVECTION BECOMES MORE ORGANIZED. FOR NOW APPEARS THE BEST
CHANCE AT SEEING MORE WIDESPREAD POOR FLYING CONDITIONS WILL COME
LATER MONDAY INTO MONDAY EVENING AS AN AXIS OF DEEPER MOISTURE
PIVOTS ACROSS.
BY WEDNESDAY INTO THURSDAY...ANOTHER AREA OF HIGH PRESSURE BUILDS
INTO THE REGION. PATCHY LATE NIGHT AND EARLY MORNING MOUNTAIN AND
RIVER VALLEY FOG WILL AGAIN BE POSSIBLE...THOUGH AIRMASS WILL BE
DRIER.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...DS/JH/WP
NEAR TERM...SK/WP
SHORT TERM...AMS
LONG TERM...AMS
AVIATION...DS/JH/WP
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1053 PM CDT SAT AUG 8 2015
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND SUNDAY
ISSUED AT 241 PM CDT SAT AUG 8 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW SURFACE
HIGH PRESSURE CENTERED OVER NORTHERN LAKE MICHIGAN...AND NOSING INTO
THE SOUTHERN PART OF THE STATE. MEANWHILE...A COLD FRONT IS SLOWLY
MOVING INTO NE MINNESOTA WHERE SMALL CLUSTERS OF THUNDERSTORMS
OCCASIONALLY DEVELOP. A FEW OTHER STORMS HAVE FIRED OVER SOUTHERN
MINNESOTA IN A WARM ADVECTION ZONE. OTHERWISE...LOW LEVEL COOL AIR
HAS DELAYED CLEARING ACROSS MUCH OF THE REGION EXCEPT FOR FAR N-C
WISCONSIN WHERE SKIES ARE STARTING TO CLEAR. AREAS OF SPRINKLES OR
LIGHT RAIN ARE FALLING OUT OF A MID-DECK OVER WESTERN AND SOUTHERN
WISCONSIN...BUT HAVE BEEN DISSIPATING AS THEY APPROACH CENTRAL
WISCONSIN. FORECAST CONCERNS INCLUDE CLOUD TRENDS AND THUNDERSTORM
POTENTIAL OVER THE NEXT 24 HOURS.
TONIGHT...MID-LEVEL WARM ADVECTION WILL RAMP UP OVER SOUTHWEST
WISCONSIN...WHILE A COLD FRONT SAGS INTO NORTHWEST WISCONSIN LATE.
THE MAJORITY OF SHORT-TERM GUIDANCE SUGGESTS ANY CONVECTION THAT
DEVELOPS OVER SOUTHERN MINNESOTA AND NORTHERN IOWA WILL DROP TO THE
SOUTHEAST OF THE AREA TONIGHT. A BETTER CHANCE OF SHOWERS AND
STORMS LOOK TO OCCUR OVER N-C WISCONSIN ALONG THE FRONT WHERE
ELEVATED INSTABILITY WILL SHIFT INTO LATE IN THE NIGHT. THIS SEEMS
REASONABLE SINCE ISOLATED CONVECTION HAS BEEN OCCURRING ALL DAY OVER
NE MINNESOTA. SO LEFT A SLIGHT CHANCE TO ACCOUNT FOR THAT.
OTHERWISE...CLOUD TRENDS CONTINUE TO POSE A HEADACHE. EAST TO
SOUTHEAST LOW LEVEL FLOW WILL CONTINUE TO COLD ADVECT THROUGH THE
EVENING OVER EASTERN WISCONSIN...BELOW A WARM LAYER CENTERED AROUND
850MB. THIS WOULD ARGUE TO SLOW DOWN THE CLEARING TREND LATER THIS
AFTERNOON AND EVENING. IF CLEARING DOES OCCUR...PATCHY FOG COULD
BECOME AN ISSUE...BUT THATS MAINLY OVER CENTRAL AND N-C WI. LOWS IN
THE UPPER 50S TO LOW 60S.
SUNDAY...WEAK MID-LEVEL WARM ADVECTION WILL SPREAD OVER NORTHEAST
WISCONSIN AS THE COLD FRONT STALLS ACROSS NW WISCONSIN. COULD HAVE
A FEW LIGHT SHOWERS/SPRINKLES GRAZE THE SOUTHERN FORECAST AREA IN
THE WARM ADVECTION ZONE...MAINLY IN THE MORNING. MOST OF THE
ATTENTION WILL BE PLACED ON THE COLD FRONT THOUGH. ISOLATED
CONVECTION WILL OCCUR ACROSS N-C WISCONSIN DURING THE
MORNING...BEFORE INSTABILITY BUILDS THROUGH THE AFTERNOON. PROGGED
SOUNDINGS INDICATE AMPLE INSTABILITY (ML CAPE UP TO 2000 J/KG)...BUT
0-6KM BULK SHEARS ARE ONLY AROUND 20 KTS. THESE PROGGED CONDITIONS
WOULD ARGUE FOR PULSE TYPE STORMS...WITH A FEW STRONG OR ISOLATED
SEVERE STORMS POSSIBLE. THE BEST COVERAGE OF STORMS APPEARS TO BE
AFTER 3 PM IN THE AFTERNOON. HIGHS RANGING FROM THE UPPER 70S NORTH
TO MID 80S SOUTH.
.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY
ISSUED AT 241 PM CDT SAT AUG 8 2015
A WEAK LOW PRESSURE SYSTEM OVER MANITOBA WILL MOVE EAST TO
SOUTHERN HUDSON BAY DURING THE NEXT COUPLE OF DAYS. THE LOW WILL
DRAG A COLD FRONT ACROSS WISCONSIN. THERE WILL BE A CHANCE FOR
SHOWERS AND THUNDERSTORMS AHEAD OF AND ALONG THE FRONT...ENDING
MONDAY AFTERNOON AS NORTHWEST WINDS FOLLOW IN AND MOISTURE GETS
SCOURED OUT OF THE AREA. ONLY AN ISOLATED SHOWER OR TWO IS
EXPECTED MONDAY NIGHT.
AFTER THE FRONT MOVES ON BY...A HIGH PRESSURE RIDGE WILL
STRENGTHEN OVER THE U.S. PLAINS STATES/MIDWEST. THE LONGWAVE
PATTERN OVER NORTH AMERICA WILL BECOME INCREASINGLY AMPLIFIED AND
A LOW PRESSURE TROUGH WILL EXPAND SOUTH OVER THE EASTERN UNITED
STATES. THIS PATTERN WILL PRODUCE A NORTHWEST FLOW OVER WISCONSIN
AND CREATE CONSIDERABLE UNCERTAINTY IN PRECIPITATION PREDICTION
FOR THE WORK WEEK. HOWEVER...THE PREDICTION OF TEMPERATURES
SHOULD BE RELIABLY WITHIN THE NORMAL TO SLIGHTLY BELOW NORMAL
RANGE FOR THIS TIME OF THE YEAR THROUGH NEXT WEEKEND. THE BLEND
OF MODELS SUGGESTS THAT...AFTER MONDAY...THE NEXT SIGNIFICANT
CHANCE FOR PRECIPITATION COMES ON FRIDAY AS A SHORTWAVE RIDES DOWN
ON THE NORTHWEST FLOW OUT OF CANADA.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1050 PM CDT SAT AUG 8 2015
SCATTERED TO BROKEN CLOUDS BETWEEN 2500 AND 3500 FEET
WILL EXIT EASTERN WISCONSIN SHORTLY AFTER MIDNIGHT. THERE IS A HIGHER
DECK AROUND 12000 FEET WHICH SHOULD KEEP MOST PLACES FROM DENSE GROUND
FOG. IF SKIES CLEAR FOR SEVERAL HOURS DENSE FOG IS POSSIBLE. SOME
MVFR OR IFR CLOUDS ARE EXPECTED TO FORM LATE TONIGHT AND DISSIPATE
BY 15Z SUNDAY WITH MAINLY VFR WEATHER IN THE AFTERNOON.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......ML
AVIATION.......RDM
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
639 PM CDT SAT AUG 8 2015
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND SUNDAY
ISSUED AT 241 PM CDT SAT AUG 8 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW SURFACE
HIGH PRESSURE CENTERED OVER NORTHERN LAKE MICHIGAN...AND NOSING INTO
THE SOUTHERN PART OF THE STATE. MEANWHILE...A COLD FRONT IS SLOWLY
MOVING INTO NE MINNESOTA WHERE SMALL CLUSTERS OF THUNDERSTORMS
OCCASIONALLY DEVELOP. A FEW OTHER STORMS HAVE FIRED OVER SOUTHERN
MINNESOTA IN A WARM ADVECTION ZONE. OTHERWISE...LOW LEVEL COOL AIR
HAS DELAYED CLEARING ACROSS MUCH OF THE REGION EXCEPT FOR FAR N-C
WISCONSIN WHERE SKIES ARE STARTING TO CLEAR. AREAS OF SPRINKLES OR
LIGHT RAIN ARE FALLING OUT OF A MID-DECK OVER WESTERN AND SOUTHERN
WISCONSIN...BUT HAVE BEEN DISSIPATING AS THEY APPROACH CENTRAL
WISCONSIN. FORECAST CONCERNS INCLUDE CLOUD TRENDS AND THUNDERSTORM
POTENTIAL OVER THE NEXT 24 HOURS.
TONIGHT...MID-LEVEL WARM ADVECTION WILL RAMP UP OVER SOUTHWEST
WISCONSIN...WHILE A COLD FRONT SAGS INTO NORTHWEST WISCONSIN LATE.
THE MAJORITY OF SHORT-TERM GUIDANCE SUGGESTS ANY CONVECTION THAT
DEVELOPS OVER SOUTHERN MINNESOTA AND NORTHERN IOWA WILL DROP TO THE
SOUTHEAST OF THE AREA TONIGHT. A BETTER CHANCE OF SHOWERS AND
STORMS LOOK TO OCCUR OVER N-C WISCONSIN ALONG THE FRONT WHERE
ELEVATED INSTABILITY WILL SHIFT INTO LATE IN THE NIGHT. THIS SEEMS
REASONABLE SINCE ISOLATED CONVECTION HAS BEEN OCCURRING ALL DAY OVER
NE MINNESOTA. SO LEFT A SLIGHT CHANCE TO ACCOUNT FOR THAT.
OTHERWISE...CLOUD TRENDS CONTINUE TO POSE A HEADACHE. EAST TO
SOUTHEAST LOW LEVEL FLOW WILL CONTINUE TO COLD ADVECT THROUGH THE
EVENING OVER EASTERN WISCONSIN...BELOW A WARM LAYER CENTERED AROUND
850MB. THIS WOULD ARGUE TO SLOW DOWN THE CLEARING TREND LATER THIS
AFTERNOON AND EVENING. IF CLEARING DOES OCCUR...PATCHY FOG COULD
BECOME AN ISSUE...BUT THATS MAINLY OVER CENTRAL AND N-C WI. LOWS IN
THE UPPER 50S TO LOW 60S.
SUNDAY...WEAK MID-LEVEL WARM ADVECTION WILL SPREAD OVER NORTHEAST
WISCONSIN AS THE COLD FRONT STALLS ACROSS NW WISCONSIN. COULD HAVE
A FEW LIGHT SHOWERS/SPRINKLES GRAZE THE SOUTHERN FORECAST AREA IN
THE WARM ADVECTION ZONE...MAINLY IN THE MORNING. MOST OF THE
ATTENTION WILL BE PLACED ON THE COLD FRONT THOUGH. ISOLATED
CONVECTION WILL OCCUR ACROSS N-C WISCONSIN DURING THE
MORNING...BEFORE INSTABILITY BUILDS THROUGH THE AFTERNOON. PROGGED
SOUNDINGS INDICATE AMPLE INSTABILITY (ML CAPE UP TO 2000 J/KG)...BUT
0-6KM BULK SHEARS ARE ONLY AROUND 20 KTS. THESE PROGGED CONDITIONS
WOULD ARGUE FOR PULSE TYPE STORMS...WITH A FEW STRONG OR ISOLATED
SEVERE STORMS POSSIBLE. THE BEST COVERAGE OF STORMS APPEARS TO BE
AFTER 3 PM IN THE AFTERNOON. HIGHS RANGING FROM THE UPPER 70S NORTH
TO MID 80S SOUTH.
.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY
ISSUED AT 241 PM CDT SAT AUG 8 2015
A WEAK LOW PRESSURE SYSTEM OVER MANITOBA WILL MOVE EAST TO
SOUTHERN HUDSON BAY DURING THE NEXT COUPLE OF DAYS. THE LOW WILL
DRAG A COLD FRONT ACROSS WISCONSIN. THERE WILL BE A CHANCE FOR
SHOWERS AND THUNDERSTORMS AHEAD OF AND ALONG THE FRONT...ENDING
MONDAY AFTERNOON AS NORTHWEST WINDS FOLLOW IN AND MOISTURE GETS
SCOURED OUT OF THE AREA. ONLY AN ISOLATED SHOWER OR TWO IS
EXPECTED MONDAY NIGHT.
AFTER THE FRONT MOVES ON BY...A HIGH PRESSURE RIDGE WILL
STRENGTHEN OVER THE U.S. PLAINS STATES/MIDWEST. THE LONGWAVE
PATTERN OVER NORTH AMERICA WILL BECOME INCREASINGLY AMPLIFIED AND
A LOW PRESSURE TROUGH WILL EXPAND SOUTH OVER THE EASTERN UNITED
STATES. THIS PATTERN WILL PRODUCE A NORTHWEST FLOW OVER WISCONSIN
AND CREATE CONSIDERABLE UNCERTAINTY IN PRECIPITATION PREDICTION
FOR THE WORK WEEK. HOWEVER...THE PREDICTION OF TEMPERATURES
SHOULD BE RELIABLY WITHIN THE NORMAL TO SLIGHTLY BELOW NORMAL
RANGE FOR THIS TIME OF THE YEAR THROUGH NEXT WEEKEND. THE BLEND
OF MODELS SUGGESTS THAT...AFTER MONDAY...THE NEXT SIGNIFICANT
CHANCE FOR PRECIPITATION COMES ON FRIDAY AS A SHORTWAVE RIDES DOWN
ON THE NORTHWEST FLOW OUT OF CANADA.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 639 PM CDT SAT AUG 8 2015
SCATTERED TO BROKEN CLOUDS BETWEEN 2500 AND 3500 FEET
EXPECTED THIS EVENING WITH A HIGHER DECK AROUND 12000 FEET. DENSE
GROUND FOG IS POSSIBLE LATE TONIGHT IF SKIES CLEAR FOR SEVERAL
HOURS BUT THAT IS NOT CERTAIN. IF ANY LOW CLOUDS OR FOG FORM LATE
TONIGHT IT SHOULD DIMINISH BY 15Z WITH VFR WEATHER IN THE
AFTERNOON.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......ML
AVIATION.......RDM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
312 PM CDT FRI AUG 7 2015
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 312 PM CDT FRI AUG 7 2015
SEVERAL CONCERNS WITH THE FORECAST DURING THIS PERIOD. THE FIRST
COMES TONIGHT AND WHETHER THERE WILL BE ANY VALLEY FOG OR NOT. IN
FAVOR OF THE FOG FORMING IS THE LITTLE BIT OF RAIN THIS MORNING
AND THE CLOUDS THAT HAVE TRAPPED THIS MOISTURE. THE 07.12Z NAM IS
THE MOST AGGRESSIVE WITH SHOWING SATURATION OCCURRING AT THE
SURFACE FOR THE VALLEY LOCATIONS. THE NAM ALSO HAS THE MOST AMOUNT
OF WIND JUST ABOVE THE SURFACE FOR MORE MIXING...WHICH GOES
AGAINST FOG FORMATION. 07.17Z RAP SOUNDINGS WHILE HAVING A DEEPER
LAYER OF LIGHT WINDS...COMES CLOSE TO SATURATING AT THE SURFACE
AND THEN REALLY DRIES OUT JUST ABOVE THE SURFACE. THE 07.12Z GFS
IS EVEN DRIER THAN THE RAP...SO HAVE DOUBTS THAT THERE WILL BE A
LOT OF FOG IN THE VALLEYS TONIGHT. ANOTHER COMPLICATING FACTOR
COULD BE THE INCREASE IN HIGH LEVEL CLOUDS FOR LATE TONIGHT AHEAD
OF AN APPROACHING SHORT WAVE TROUGH. PATCHY VALLEY FOG WAS ALREADY
IN THE FORECAST AND DO NOT PLAN TO MAKE ANY CHANGES TO THIS.
WITH THE APPROACHING SHORT WAVE TROUGH...THE GFS SEEMS TO HAVE THE
MOST SUPPORT FROM THE OTHER MODELS WITH THE 07.12Z ECMWF LOOKING
SIMILAR ALONG WITH THE 07.12Z HI-RES ARW AND NMM. WATER VAPOR
SATELLITE INDICATES THIS WAVE IS COMING OUT OF THE ROCKIES OVER
EASTERN WYOMING AND NORTHERN COLORADO THIS AFTERNOON AND SHOULD
THEN TRACK EAST ACROSS IOWA INTO SOUTHERN WISCONSIN AND NORTHERN
ILLINOIS BY LATE SATURDAY MORNING. THE GFS SUGGESTS THIS WAVE WILL
PRODUCE SOME WEAK TO MODERATE PV ADVECTION IN THE 500-300 MB LAYER
ACROSS NORTHEAST IOWA INTO FAR SOUTHERN WISCONSIN LATE TONIGHT
INTO EARLY SATURDAY MORNING. THE BOUNDARY THAT WENT THROUGH TODAY
SHOULD BE HUNG UP OVER CENTRAL IOWA AND IT IS EXPECTED THAT WEAK
TO MODERATE FRONTOGENESIS WILL OCCUR NORTH OF THIS BOUNDARY. THE
BEST ISENTROPIC UP GLIDE ON THE 310K SURFACE IS EXPECTED TO
REMAIN SOUTH OF THE BOUNDARY ACROSS CENTRAL AND SOUTHERN IOWA WITH
POSSIBLY 1 TO 2 UBAR/S OVER NORTHEAST IOWA. THE GENERAL CONSENSUS
AMONG THE MODELS IS THAT A COMPLEX OF SHOWERS AND STORMS SHOULD
FORM OVER NEBRASKA TONIGHT AND MOVE EAST ALONG AND NORTH OF THE
BOUNDARY. THE GFS AND HI-RES ARW AND NMM WOULD SUGGEST THERE IS AT
LEAST A CHANCE THAT THIS COMPLEX SURVIVES LONG ENOUGH TO GET INTO
THE SOUTHERN PARTS OF THE FORECAST AREA WHILE THE 07.12Z ECMWF
STARTS TO DISSIPATE THE COMPLEX AND ONLY BRINGS IN SOME REMAINS
SATURDAY AFTERNOON ACROSS THE SOUTH. WILL BRING IN SOME 20 TO 40
PERCENT CHANCES ACROSS NORTHEAST IOWA SATURDAY MORNING FOR THIS
COMPLEX.
ANOTHER SHORT WAVE TROUGH IS THEN EXPECTED TO COME OUT OF THE
ROCKIES AND TRACK ACROSS THE REGION SATURDAY NIGHT. THE TRACK AND
FORCING LOOK TO BE VERY SIMILAR TO THE WAVE FOR LATE TONIGHT INTO
SATURDAY MORNING WITH THE EXCEPTION THAT THE SURFACE BOUNDARY
SHOULD GET PUSHED FARTHER SOUTH INTO SOUTHERN IOWA OR NORTHERN
MISSOURI. THE COMPLEX OF STORMS WITH THIS NEXT WAVE IS EXPECTED TO
FORM OVER SOUTHWEST IOWA AND THEN TRACK EAST AND SHOULD LARGELY
STAY TO THE SOUTH OF THE FORECAST AREA. THE GFS IS SLIGHTLY
FARTHER NORTH THAN THE ECMWF AND TO HONOR THIS WILL HAVE SOME 20
TO 40 PERCENT CHANCES FROM ABOUT INTERSTATE 90 SOUTH.
BY SUNDAY NIGHT THE MEAN RIDGE WILL BE TRYING TO BUILD OVER THE
ROCKIES WITH AN UPPER LEVEL LOW OVER NORTHERN ONTARIO. THIS WILL
START TO SET UP A NORTHWEST FLOW OVER THE REGION WITH THE
POSSIBILITY OF A WEAK SHORT WAVE TROUGH ROTATING AROUND THE UPPER
LEVEL LOW AND ACROSS THE AREA. THE FORCING WITH THIS WAVE LOOKS TO
BE RATHER WEAK...BUT IT COULD PUSH A WEAK SURFACE BOUNDARY INTO
THE AREA WITH THE POSSIBILITY OF SOME ACTIVITY ALONG IT. WILL
CARRY SOME 30 TO 40 PERCENT CHANCES SUNDAY FOR THIS FEATURE WITH
SOME LINGERING 20 TO 30 PERCENT CHANCES INTO SUNDAY NIGHT.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 312 PM CDT FRI AUG 7 2015
ONCE THE SHORT WAVE TROUGH FROM SUNDAY NIGHT EXITS THE AREA...A
LARGE AREA OF HIGH PRESSURE WILL BUILD IN OVER THE UPPER MIDWEST.
THIS HIGH LOOKS TO DOMINATE THE REGION FROM MONDAY NIGHT THROUGH
WEDNESDAY NIGHT. THE ECMWF WOULD SUGGESTS IT HOLDS TIGHT OVER THE
REGION THROUGH THE END OF THE WEEK WHILE THE GFS BRINGS A COLD
FRONT ACROSS THE UPPER MIDWEST THURSDAY THROUGH FRIDAY. WILL JUST
CARRY SOME LOW 20 TO 30 PERCENT RAIN CHANCES LATE IN THE PERIOD TO
HONOR THE GFS SOLUTION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1250 PM CDT FRI AUG 7 2015
WITH SHOWERS AND THUNDERSTORMS FROM THIS MORNING NOW WELL EAST OF
TAF AIRFIELDS AND CEILINGS RISING ABOVE 3000 FT AGL...EXPECT VFR
CONDITIONS AT KRST/KLSE THROUGH AT LEAST 08.06Z. SCT-BKN AFTERNOON
CU WILL BREAK UP AND DISSIPATE LATER THIS EVENING...LEAVING MOSTLY
CLEAR SKIES FOR THE LATE EVENING INTO THE EARLY MORNING HOURS.
WEST-NORTHWEST WINDS FROM 8 TO 12 KTS WILL DECREASE SOON AFTER
SUNSET...BECOMING LIGHT THIS EVENING.
PRIMARY CONCERN TONIGHT WILL BE FOG POTENTIAL...ESPECIALLY AT
KLSE. VARIOUS FORECAST GUIDANCE DIFFERS ON THE DEPTH OF LIGHT
WINDS OVERNIGHT AS WELL AS THE DEGREE OF INCREASING MID-HIGH
CLOUDS DURING THE CRITICAL 09-13Z PERIOD. IF CLOUDS ARE SLOWER TO
MOVE INTO THE REGION AND A DEEP LAYER OF LIGHT WIND MATERIALIZES...
FOG CHANCES INCREASE GREATLY. FOR NOW...NOT ENOUGH CONFIDENCE TO
INTRODUCE IFR CONDITIONS IN FOG AND WILL KEEP 4SM/BR AT KLSE
BEGINNING AT 08.10Z. WILL ALLOW FUTURE SHIFTS TO MONITOR
CONDITIONS AND ADJUST AS NECESSARY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...04
LONG TERM...04
AVIATION...ROGERS
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1205 PM CDT FRI AUG 7 2015
UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE
.UPDATE...
ISSUED AT 1205 PM CDT FRI AUG 7 2015
THE LARGE SHIELD OF RAIN HAS MOVED INTO THE NORTHEASTERN QUARTER
OF WISCONSIN WITH LOCALLY HEAVY RAIN FALLING AT TIMES. A FEW
LOCATIONS IN CENTRAL WISCONSIN HAVE ALREADY EXCEEDED AN INCH OF
RAIN BEFORE NOON. A RELATIVELY STABLE ATMOSPHERE APPEARS TO BE
SUPPRESSING THUNDER POTENTIAL...BUT A SMALL HANDFUL OF STRIKES
HAVE BEEN DETECTED THROUGH THE MORNING IN THE SOUTHERN TIER OF THE
CWA. TO THIS POINT...THE HEAVIEST RAIN ALSO SEEMS CONFINED TO THE
SOUTH...AND FORECAST UPDATES THROUGH THE MORNING HAVE ATTEMPTED
TO REFLECT THIS. MESO MODELS CONTINUE TO INSIST ON DEVELOPMENT OF
HEAVIER RAIN IN NORTHEAST WISCONSIN THIS AFTERNOON...AND IN
DEFERENCE TO THEIR CONSISTENCY WILL NOT TOTALLY ABANDON THAT
POTENTIAL IN FORECAST THERE YET. BUT TO THIS POINT...RAIN THERE
HAS BEEN LIGHTER AND MORE SCATTERED.
&&
.SYNOPSIS...
ISSUED AT 406 AM CDT FRI AUG 7 2015
MUCH NEEDED RAINFALL EXPECTED FOR MOST OF THE AREA TODAY.
THE POSN OF THE MAIN LARGE-SCALE FEATURES WL CHG LITTLE DURING THE
FCST PERIOD...WITH TROF POSNS NEAR THE COASTS AND RIDGING ACRS
THE CENTRAL PART OF THE CONTINENT. THE MAIN WESTERLIES ACRS THE
NRN CONUS CURRENTLY ARE RATHER LOW-AMPLITUDE...AS A SERIES OF
SHRTWVS IS DISTORTING THE MID-CONUS RIDGE. THE MAIN CHG DURING THE
FCST PERIOD WL BE A MARKED AMPLIFICATION OF THE RIDGE NEXT WEEK.
TEMPS WL NOT VARY TOO MUCH FM SEASONAL NORMALS. THE MAIN
OPPORTUNITIES FOR PCPN WL OCCUR TDA AND DURING THE LATTER PART OF
THE WEEKEND. AFTER TDA/S SYSTEM EXITS THE AREA...PCPN AMNTS WL
PROBABLY BE BLO NORMAL FOR THE REST OF THE PERIOD.
&&
.SHORT TERM...TODAY...TONIGHT...AND SATURDAY
ISSUED AT 406 AM CDT FRI AUG 7 2015
FCST FOCUS IS ON SHARS-LIKE SYSTEM CROSSING THE AREA TDA. THE
SYSTEM PRODUCED SIG WX TO OUR W YDA...WITH SEVERAL TORNADOES
APPARENTLY OCCURRING IN MN...AND HVY RAIN IN SOME PLACES AS WELL.
THE SYSTEM IS MOVG OUT OF THE AXIS OF GREATEST MOISTURE AND
INSTABILITY...SO AN EXACT REPEAT IS UNLIKELY ACRS OUR AREA TDA.
STILL...THE SYSTEM WL ACT ON INCRG MOISTURE TO GENERATE FAIRLY
WIDESPREAD SHRA ACRS THE FCST AREA TDA. BASED ON EXTRAP OF RADAR
AND STLT IMAGERY...NEARLY CLOSED UPR SHRTWV WL DRIVE EWD RIGHT
ACRS THE FCST AREA. COMMA-HEAD STRUCTURE WL LIKELY TRACK ACRS
N-C/NE WI...GENERALLY N OF HIGHWAY 29...RESULTING IN A WIDESPREAD
SOAKING RAINFALL ACRS THE N. WIDESPREAD CLDS AND PCPN WL GREATLY
LIMIT DESTABILIZATION...AND SUPPORT ONLY ISOLD THUNDER. BUT WL
NEED TO KEEP A CLOSE WATCH ON THE FAR SRN PART OF THE FCST AREA.
ALTHOUGH UNLIKELY...IF SUFFICIENT BREAKS IN THE CLDS WERE TO
DEVELOP FOR DESTABILIZATION TO OCCUR...CONDITIONS COULD BECOME
FAVORABLE FOR LOW-TOPPED SUPERCELLS.
ADDED HVY RAINFALL ATTRIBUTE TO THE GRIDS...NOT BECAUSE OF THE
POTENTIAL FOR TORRENTIAL RAINS WITH TSTMS...BUT MORE FOR EFFICIENT
SHRA/TSRA THAT COULD PERSIST FOR SEVERAL HRS AS THE COMMA HEAD
STRUCTURE PUSHES ACRS THE AREA. SOME RUNS OF THE HRRR PRODUCED
RAINFALLS OF UP TO 3.5 INCHES ACRS PORTIONS OF THE FCST AREA. A
WIDESPREAD 1-2 INCH RAINFALL ACRS THE N SEEMS MORE LIKELY...WITH A
FEW LOCATIONS POSSIBLY EXCEEDING 2 INCHES. THE DURATION OF THE
RAINFALL SEEMS TO FAVOR MAINLY PONDING OF WATER IN LOW-LYING AREAS
RATHER THAN FLASH FLOODING. WL DETAIL SITN IN THE HWO.
TIMING THE ENDING OF THE PCPN WAS DIFFICULT. BACK EDGE OF PCPN WAS
STILL MAKING STEADY EWD PROGRESS EARLY THIS MORNING...AND PURE
EXTRAPOLATION WOULD TAKE IT OUT OF THE ARE MUCH FASTER THAN
DEPICTED ON THE MODELS. SUSPECT SYSTEM WL SLOW A BIT AS UPR
SPEED MAX BECOMES SITUATED MORE ON THE UPSTREAM SIDE OF THE
TROF...AND SOME ADDITIONAL PCPN DEVELOPMENT WL EVENTUALLY OCCUR
ALONG THE TRAILING EDGE OF THE SYSTEM. BUILT POP GRIDS WITH
CATEGORICAL POPS SHIFTG THROUGH THE N DURING THE DAY...BUT
LINGERED SCT/ISOLD POPS BACK TO THE SW WELL INTO TNGT. TEMPS TDA
NOT LIKELY TO RISE VERY FAR WITH WIDESPREAD CLDS AND PCPN.
EXPECT SOME FOG TO DEVELOP OVERNIGHT. THERE COULD ALSO BE QUITE A
BIT OF LINGERING LOW CLD COVER. IF BREAKS IN THE LOW CLDS ARE MORE
SIG THAN EXPECTED...DENSE FOG COULD BECOME A PROBLEM.
QUIET WX EXPECTED SAT AS THE NEXT SYSTEM WL FIRST BE APPROACHING
FM THE W. SLOWED THE ARRIVAL OF THE POPS WITH THAT SYSTEM FM WHAT
WAS IN PREV FCST.
.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY
ISSUED AT 406 AM CDT FRI AUG 7 2015
A PATTERN SHIFT IS EXPECTED BY EARLY NEXT WEEK AS 500MB RIDGE
BUILDS ACROSS THE ROCKIES AND TROUGH DEEPENS ACROSS EASTERN
CANADA. THIS WILL LEAVE THE REGION IN A NORTHWEST FLOW PATTERN.
TEMPERATURES WILL TREND TOWARDS BELOW NORMAL READINGS BY THE
MIDDLE OF NEXT WEEK BEFORE REBOUNDING LATE IN THE WEEK AHEAD
OF A COLD FRONT.
MAIN CONCERN WILL BE THE TIMING OF PRECIPITATION CHANCES SATURDAY
NIGHT INTO SUNDAY NIGHT AS A COLD FRONT MOVES THROUGH THE AREA.
MODELS IN BETTER AGREEMENT WITH TIMING OF PRECIPITATION. CHANCES
FOR SHOWERS AND STORMS WILL INCREASE LATER SATURDAY NIGHT...WITH
THE BEST CHANCE FOR SHOWERS AND STORMS SUNDAY INTO SUNDAY EVENING
AS FRONT MOVES THROUGH THE REGION. MAIN CONCERN WILL THE
POSSIBILITY OF LOCALLY HEAVY RAIN. ENOUGH LINGERING MOISTURE AND
WEAK DISTURBANCE MOVING ACROSS THE REGION ON MONDAY COULD TRIGGER
AN ISOLATED SHOWER OR STORM ACROSS NORTHEAST OR EAST-CENTRAL
WISCONSIN. ANOTHER DISTURBANCE DROPPING SOUTHEAST OUT OF CANADA
NEEDS TO BE WATCHED FOR TUESDAY INTO TUESDAY AFTERNOON. LATEST
ECMWF DOES DEPICT PRECIPITATION DURING THIS PERIOD. WILL WAIT
FOR A FEW MORE MODEL RUNS TO SEE IF THIS SCENARIO IS STILL
DEPICTED BEFORE ADDING A CHANCE OF PRECIPITATION DURING THIS
PERIOD. OTHERWISE...DRY CONDITIONS WILL PREVAIL THROUGH THURSDAY.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1205 PM CDT FRI AUG 7 2015
FLIGHT CONDITIONS HAVE GENERALLY DETERIORATED AS EXPECTED
TODAY...BUT HAVE BEEN FLUCTUATING WITH RAIN INTENSITY THROUGH THE
MORNING. CONDITIONS ARE EXPECTED TO REMAIN POOR TONIGHT...AND LOW
CIGS/VIS SHOULD BE EXPECTED BEHIND THE RAIN. GUIDANCE SUGGESTS
SEVERAL HOURS OF DENSE FOG FOR THE WESTERN SITES OVERNIGHT. THIS
MAY BE OVERKILL...BUT FOG IS A TRICKY BEAST...AND WILL INTRODUCE
A TEMPO PERIOD OF LIFR AT RHI...AUW...AND CWA IN THE PRE-DAWN
HOURS AS WE WILL HAVE POOR CONDITIONS...LIGHT WINDS...AND PLENTY
OF LINGERING MOISTURE. LATER ISSUANCES WILL HAVE TO REFINE BASED
ON THE EVOLUTION OF THE POST-RAIN ENVIRONMENT. &&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE.........LUCHS
SYNOPSIS.......SKOWRONSKI
SHORT TERM.....SKOWRONSKI
LONG TERM......ECKBERG
AVIATION.......LUCHS
AREA FORECAST DISCUSSION...UPDATED
NWS GREEN BAY WI
644 AM CDT FRI AUG 7 2015
NEW INFORMATION ADDED TO UPDATE SECTION
.UPDATE...
ISSUED AT 639 AM CDT FRI AUG 7 2015
SOME VERY IMPRESSIVE RAINFALL TOTALS COMING IN FM WRN WI. EAU HAD
2.88 INCHES ALREADY. THE ATM IS STILL MUCH MORE STABLE IN THE
E...THOUGH THE INSTABILITY AXIS OUT W SHOULD GRADUALLY LEAN EWD
INTO THE FCST AREA. POSN OF UPR VORT ON STLT IMAGERY AS WELL AS
THE HIGHEST RETURNS ON RADAR MOSAIC SUGGEST AXIS OF HEAVIEST RAIN
COULD OCCUR FARTHER S THAN EARLIER ANTICIPATED. UPDATED GRIDS
BASED ON THIS IDEA ALREADY SENT. WL TWEAK HWO TO REMOVE WORDING
CONFINING HEAVY RAIN TO THE NORTH...AND ISSUE AN SPS.
&&
.SYNOPSIS...
ISSUED AT 406 AM CDT FRI AUG 7 2015
MUCH NEEDED RAINFALL EXPECTED FOR MOST OF THE AREA TODAY.
THE POSN OF THE MAIN LARGE-SCALE FEATURES WL CHG LITTLE DURING THE
FCST PERIOD...WITH TROF POSNS NEAR THE COASTS AND RIDGING ACRS
THE CENTRAL PART OF THE CONTINENT. THE MAIN WESTERLIES ACRS THE
NRN CONUS CURRENTLY ARE RATHER LOW-AMPLITUDE...AS A SERIES OF
SHRTWVS IS DISTORTING THE MID-CONUS RIDGE. THE MAIN CHG DURING THE
FCST PERIOD WL BE A MARKED AMPLIFICATION OF THE RIDGE NEXT WEEK.
TEMPS WL NOT VARY TOO MUCH FM SEASONAL NORMALS. THE MAIN
OPPORTUNITIES FOR PCPN WL OCCUR TDA AND DURING THE LATTER PART OF
THE WEEKEND. AFTER TDA/S SYSTEM EXITS THE AREA...PCPN AMNTS WL
PROBABLY BE BLO NORMAL FOR THE REST OF THE PERIOD.
&&
.SHORT TERM...TODAY...TONIGHT...AND SATURDAY
ISSUED AT 406 AM CDT FRI AUG 7 2015
FCST FOCUS IS ON SHARS-LIKE SYSTEM CROSSING THE AREA TDA. THE
SYSTEM PRODUCED SIG WX TO OUR W YDA...WITH SEVERAL TORNADOES
APPARENTLY OCCURRING IN MN...AND HVY RAIN IN SOME PLACES AS WELL.
THE SYSTEM IS MOVG OUT OF THE AXIS OF GREATEST MOISTURE AND
INSTABILITY...SO AN EXACT REPEAT IS UNLIKELY ACRS OUR AREA TDA.
STILL...THE SYSTEM WL ACT ON INCRG MOISTURE TO GENERATE FAIRLY
WIDESPREAD SHRA ACRS THE FCST AREA TDA. BASED ON EXTRAP OF RADAR
AND STLT IMAGERY...NEARLY CLOSED UPR SHRTWV WL DRIVE EWD RIGHT
ACRS THE FCST AREA. COMMA-HEAD STRUCTURE WL LIKELY TRACK ACRS
N-C/NE WI...GENERALLY N OF HIGHWAY 29...RESULTING IN A WIDESPREAD
SOAKING RAINFALL ACRS THE N. WIDESPREAD CLDS AND PCPN WL GREATLY
LIMIT DESTABILIZATION...AND SUPPORT ONLY ISOLD THUNDER. BUT WL
NEED TO KEEP A CLOSE WATCH ON THE FAR SRN PART OF THE FCST AREA.
ALTHOUGH UNLIKELY...IF SUFFICIENT BREAKS IN THE CLDS WERE TO
DEVELOP FOR DESTABILIZATION TO OCCUR...CONDITIONS COULD BECOME
FAVORABLE FOR LOW-TOPPED SUPERCELLS.
ADDED HVY RAINFALL ATTRIBUTE TO THE GRIDS...NOT BECAUSE OF THE
POTENTIAL FOR TORRENTIAL RAINS WITH TSTMS...BUT MORE FOR EFFICIENT
SHRA/TSRA THAT COULD PERSIST FOR SEVERAL HRS AS THE COMMA HEAD
STRUCTURE PUSHES ACRS THE AREA. SOME RUNS OF THE HRRR PRODUCED
RAINFALLS OF UP TO 3.5 INCHES ACRS PORTIONS OF THE FCST AREA. A
WIDESPREAD 1-2 INCH RAINFALL ACRS THE N SEEMS MORE LIKELY...WITH A
FEW LOCATIONS POSSIBLY EXCEEDING 2 INCHES. THE DURATION OF THE
RAINFALL SEEMS TO FAVOR MAINLY PONDING OF WATER IN LOW-LYING AREAS
RATHER THAN FLASH FLOODING. WL DETAIL SITN IN THE HWO.
TIMING THE ENDING OF THE PCPN WAS DIFFICULT. BACK EDGE OF PCPN WAS
STILL MAKING STEADY EWD PROGRESS EARLY THIS MORNING...AND PURE
EXTRAPOLATION WOULD TAKE IT OUT OF THE ARE MUCH FASTER THAN
DEPICTED ON THE MODELS. SUSPECT SYSTEM WL SLOW A BIT AS UPR
SPEED MAX BECOMES SITUATED MORE ON THE UPSTREAM SIDE OF THE
TROF...AND SOME ADDITIONAL PCPN DEVELOPMENT WL EVENTUALLY OCCUR
ALONG THE TRAILING EDGE OF THE SYSTEM. BUILT POP GRIDS WITH
CATEGORICAL POPS SHIFTG THROUGH THE N DURING THE DAY...BUT
LINGERED SCT/ISOLD POPS BACK TO THE SW WELL INTO TNGT. TEMPS TDA
NOT LIKELY TO RISE VERY FAR WITH WIDESPREAD CLDS AND PCPN.
EXPECT SOME FOG TO DEVELOP OVERNIGHT. THERE COULD ALSO BE QUITE A
BIT OF LINGERING LOW CLD COVER. IF BREAKS IN THE LOW CLDS ARE MORE
SIG THAN EXPECTED...DENSE FOG COULD BECOME A PROBLEM.
QUIET WX EXPECTED SAT AS THE NEXT SYSTEM WL FIRST BE APPROACHING
FM THE W. SLOWED THE ARRIVAL OF THE POPS WITH THAT SYSTEM FM WHAT
WAS IN PREV FCST.
.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY
ISSUED AT 406 AM CDT FRI AUG 7 2015
A PATTERN SHIFT IS EXPECTED BY EARLY NEXT WEEK AS 500MB RIDGE
BUILDS ACROSS THE ROCKIES AND TROUGH DEEPENS ACROSS EASTERN
CANADA. THIS WILL LEAVE THE REGION IN A NORTHWEST FLOW PATTERN.
TEMPERATURES WILL TREND TOWARDS BELOW NORMAL READINGS BY THE
MIDDLE OF NEXT WEEK BEFORE REBOUNDING LATE IN THE WEEK AHEAD
OF A COLD FRONT.
MAIN CONCERN WILL BE THE TIMING OF PRECIPITATION CHANCES SATURDAY
NIGHT INTO SUNDAY NIGHT AS A COLD FRONT MOVES THROUGH THE AREA.
MODELS IN BETTER AGREEMENT WITH TIMING OF PRECIPITATION. CHANCES
FOR SHOWERS AND STORMS WILL INCREASE LATER SATURDAY NIGHT...WITH
THE BEST CHANCE FOR SHOWERS AND STORMS SUNDAY INTO SUNDAY EVENING
AS FRONT MOVES THROUGH THE REGION. MAIN CONCERN WILL THE
POSSIBILITY OF LOCALLY HEAVY RAIN. ENOUGH LINGERING MOISTURE AND
WEAK DISTURBANCE MOVING ACROSS THE REGION ON MONDAY COULD TRIGGER
AN ISOLATED SHOWER OR STORM ACROSS NORTHEAST OR EAST-CENTRAL
WISCONSIN. ANOTHER DISTURBANCE DROPPING SOUTHEAST OUT OF CANADA
NEEDS TO BE WATCHED FOR TUESDAY INTO TUESDAY AFTERNOON. LATEST
ECMWF DOES DEPICT PRECIPITATION DURING THIS PERIOD. WILL WAIT
FOR A FEW MORE MODEL RUNS TO SEE IF THIS SCENARIO IS STILL
DEPICTED BEFORE ADDING A CHANCE OF PRECIPITATION DURING THIS
PERIOD. OTHERWISE...DRY CONDITIONS WILL PREVAIL THROUGH THURSDAY.
&&
.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 406 AM CDT FRI AUG 7 2015
FLIGHT CONDITIONS EXPECTED TO DETERIORATE TDA...AND WL PROBABLY
REMAIN POOR TNGT. PREV TAF SET BROUGHT CONDITIONS DOWN TO LOWER-
END MVFR AND IFR CONDITIONS BY MIDNIGHT SAT. PLAN TO CONT THAT
WITH THE 12Z ISSUANCE AS THE POOR FLIGHT CONDITIONS WL TAKE UNTIL
AT LEAST SAT MORNING TO IMPROVE.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE.........SKOWRONSKI
SYNOPSIS.......SKOWRONSKI
SHORT TERM.....SKOWRONSKI
LONG TERM......ECKBERG
AVIATION.......SKOWRONSKI
FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE
.SYNOPSIS...
ISSUED AT 406 AM CDT FRI AUG 7 2015
MUCH NEEDED RAINFALL EXPECTED FOR MOST OF THE AREA TODAY.
THE POSN OF THE MAIN LARGE-SCALE FEATURES WL CHG LITTLE DURING THE
FCST PERIOD...WITH TROF POSNS NEAR THE COASTS AND RIDGING ACRS
THE CENTRAL PART OF THE CONTINENT. THE MAIN WESTERLIES ACRS THE
NRN CONUS CURRENTLY ARE RATHER LOW-AMPLITUDE...AS A SERIES OF
SHRTWVS IS DISTORTING THE MID-CONUS RIDGE. THE MAIN CHG DURING THE
FCST PERIOD WL BE A MARKED AMPLIFICATION OF THE RIDGE NEXT WEEK.
TEMPS WL NOT VARY TOO MUCH FM SEASONAL NORMALS. THE MAIN
OPPORTUNITIES FOR PCPN WL OCCUR TDA AND DURING THE LATTER PART OF
THE WEEKEND. AFTER TDA/S SYSTEM EXITS THE AREA...PCPN AMNTS WL
PROBABLY BE BLO NORMAL FOR THE REST OF THE PERIOD. &&
.SHORT TERM...TODAY...TONIGHT...AND SATURDAY
ISSUED AT 406 AM CDT FRI AUG 7 2015
FCST FOCUS IS ON SHARS-LIKE SYSTEM CROSSING THE AREA TDA. THE
SYSTEM PRODUCED SIG WX TO OUR W YDA...WITH SEVERAL TORNADOES
APPARENTLY OCCURRING IN MN...AND HVY RAIN IN SOME PLACES AS WELL.
THE SYSTEM IS MOVG OUT OF THE AXIS OF GREATEST MOISTURE AND
INSTABILITY...SO AN EXACT REPEAT IS UNLIKELY ACRS OUR AREA TDA.
STILL...THE SYSTEM WL ACT ON INCRG MOISTURE TO GENERATE FAIRLY
WIDESPREAD SHRA ACRS THE FCST AREA TDA. BASED ON EXTRAP OF RADAR
AND STLT IMAGERY...NEARLY CLOSED UPR SHRTWV WL DRIVE EWD RIGHT
ACRS THE FCST AREA. COMMA-HEAD STRUCTURE WL LIKELY TRACK ACRS
N-C/NE WI...GENERALLY N OF HIGHWAY 29...RESULTING IN A WIDESPREAD
SOAKING RAINFALL ACRS THE N. WIDESPREAD CLDS AND PCPN WL GREATLY
LIMIT DESTABILIZATION...AND SUPPORT ONLY ISOLD THUNDER. BUT WL
NEED TO KEEP A CLOSE WATCH ON THE FAR SRN PART OF THE FCST AREA.
ALTHOUGH UNLIKELY...IF SUFFICIENT BREAKS IN THE CLDS WERE TO
DEVELOP FOR DESTABILIZATION TO OCCUR...CONDITIONS COULD BECOME
FAVORABLE FOR LOW-TOPPED SUPERCELLS.
ADDED HVY RAINFALL ATTRIBUTE TO THE GRIDS...NOT BECAUSE OF THE
POTENTIAL FOR TORRENTIAL RAINS WITH TSTMS...BUT MORE FOR EFFICIENT
SHRA/TSRA THAT COULD PERSIST FOR SEVERAL HRS AS THE COMMA HEAD
STRUCTURE PUSHES ACRS THE AREA. SOME RUNS OF THE HRRR PRODUCED
RAINFALLS OF UP TO 3.5 INCHES ACRS PORTIONS OF THE FCST AREA. A
WIDESPREAD 1-2 INCH RAINFALL ACRS THE N SEEMS MORE LIKELY...WITH A
FEW LOCATIONS POSSIBLY EXCEEDING 2 INCHES. THE DURATION OF THE
RAINFALL SEEMS TO FAVOR MAINLY PONDING OF WATER IN LOW-LYING AREAS
RATHER THAN FLASH FLOODING. WL DETAIL SITN IN THE HWO.
TIMING THE ENDING OF THE PCPN WAS DIFFICULT. BACK EDGE OF PCPN WAS
STILL MAKING STEADY EWD PROGRESS EARLY THIS MORNING...AND PURE
EXTRAPOLATION WOULD TAKE IT OUT OF THE ARE MUCH FASTER THAN
DEPICTED ON THE MODELS. SUSPECT SYSTEM WL SLOW A BIT AS UPR
SPEED MAX BECOMES SITUATED MORE ON THE UPSTREAM SIDE OF THE
TROF...AND SOME ADDITIONAL PCPN DEVELOPMENT WL EVENTUALLY OCCUR
ALONG THE TRAILING EDGE OF THE SYSTEM. BUILT POP GRIDS WITH
CATEGORICAL POPS SHIFTG THROUGH THE N DURING THE DAY...BUT
LINGERED SCT/ISOLD POPS BACK TO THE SW WELL INTO TNGT. TEMPS TDA
NOT LIKELY TO RISE VERY FAR WITH WIDESPREAD CLDS AND PCPN.
EXPECT SOME FOG TO DEVELOP OVERNIGHT. THERE COULD ALSO BE QUITE A
BIT OF LINGERING LOW CLD COVER. IF BREAKS IN THE LOW CLDS ARE MORE
SIG THAN EXPECTED...DENSE FOG COULD BECOME A PROBLEM.
QUIET WX EXPECTED SAT AS THE NEXT SYSTEM WL FIRST BE APPROACHING
FM THE W. SLOWED THE ARRIVAL OF THE POPS WITH THAT SYSTEM FM WHAT
WAS IN PREV FCST.
.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY
ISSUED AT 406 AM CDT FRI AUG 7 2015
A PATTERN SHIFT IS EXPECTED BY EARLY NEXT WEEK AS 500MB RIDGE
BUILDS ACROSS THE ROCKIES AND TROUGH DEEPENS ACROSS EASTERN
CANADA. THIS WILL LEAVE THE REGION IN A NORTHWEST FLOW PATTERN.
TEMPERATURES WILL TREND TOWARDS BELOW NORMAL READINGS BY THE
MIDDLE OF NEXT WEEK BEFORE REBOUNDING LATE IN THE WEEK AHEAD
OF A COLD FRONT.
MAIN CONCERN WILL BE THE TIMING OF PRECIPITATION CHANCES SATURDAY
NIGHT INTO SUNDAY NIGHT AS A COLD FRONT MOVES THROUGH THE AREA.
MODELS IN BETTER AGREEMENT WITH TIMING OF PRECIPITATION. CHANCES
FOR SHOWERS AND STORMS WILL INCREASE LATER SATURDAY NIGHT...WITH
THE BEST CHANCE FOR SHOWERS AND STORMS SUNDAY INTO SUNDAY EVENING
AS FRONT MOVES THROUGH THE REGION. MAIN CONCERN WILL THE
POSSIBILITY OF LOCALLY HEAVY RAIN. ENOUGH LINGERING MOISTURE AND
WEAK DISTURBANCE MOVING ACROSS THE REGION ON MONDAY COULD TRIGGER
AN ISOLATED SHOWER OR STORM ACROSS NORTHEAST OR EAST-CENTRAL
WISCONSIN. ANOTHER DISTURBANCE DROPPING SOUTHEAST OUT OF CANADA
NEEDS TO BE WATCHED FOR TUESDAY INTO TUESDAY AFTERNOON. LATEST
ECMWF DOES DEPICT PRECIPITATION DURING THIS PERIOD. WILL WAIT
FOR A FEW MORE MODEL RUNS TO SEE IF THIS SCENARIO IS STILL
DEPICTED BEFORE ADDING A CHANCE OF PRECIPITATION DURING THIS
PERIOD. OTHERWISE...DRY CONDITIONS WILL PREVAIL THROUGH THURSDAY.
&&
.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 406 AM CDT FRI AUG 7 2015
FLIGHT CONDITIONS EXPECTED TO DETERIORATE TDA...AND WL PROBABLY
REMAIN POOR TNGT. PREV TAF SET BROUGHT CONDITIONS DOWN TO LOWER-
END MVFR AND IFR CONDITIONS BY MIDNIGHT SAT. PLAN TO CONT THAT
WITH THE 12Z ISSUANCE AS THE POOR FLIGHT CONDITIONS WL TAKE UNTIL
AT LEAST SAT MORNING TO IMPROVE.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS.......SKOWRONSKI
SHORT TERM.....SKOWRONSKI
LONG TERM......ECKBERG
AVIATION.......SKOWRONSKI
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1231 PM MDT FRI AUG 7 2015
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 400 AM MDT FRI AUG 7 2015
THE MAIN CONCERN WITH THIS PORTION OF THE FORECAST IS THE POTENTIAL
FOR SEVERE CONVECTION THIS AFTERNOON/EVENING IN THE NEBRASKA PANHANDLE
AND THE POTENTIAL FOR RAIN AND THUNDERSTORMS ACROSS AREAS WEST OF
THE LARAMIE RANGE THIS EVENING.
TODAY AND TONIGHT:
LATEST WATER VAPOR LOOP WAS SHOWING A FAIRLY STRONG SHORTWAVE
MOVING THROUGH CENTRAL CALIFORNIA. AHEAD OF THIS FEATURE...THERE
IS A GOOD FETCH OF MOISTURE FROM THE PACIFIC WITH THE BULK OF THIS
MOISTURE STILL IN NEVADA AND UTAH. MEANWHILE...IN THE HIGH PLAINS
OF NORTHEAST COLORADO AND THE SOUTHERN PANHANDLE THE SURFACE
OBSERVATIONS ARE SHOWING QUITE A POOL OF LOW LEVEL MOISTURE WITH
DEWPOINTS IN THE 60S. SURFACE ANALYSIS IS ALREADY SHOWING THE LEE
TROUGH DEVELOPING IN RESPONSE TO THE SHORTWAVE IN CALIFORNIA.
PIECES OF ENERGY EJECTING AHEAD OF THIS SHORTWAVE COULD SET THE
STAGE FOR AN ACTIVE SEVERE WEATHER DAY ACROSS THE HIGH PLAINS OF
NEBRASKA AND PORTIONS OF SOUTHEAST WYOMING. THE MAIN QUESTION WILL
BE THE LOCATION OF THE BEST LOW LEVEL CONVERGENCE. THE HRRR IS
SHOWING THE INITIAL BOUNDARY SITUATED FROM KIMBALL TO ALLIANCE
NEBRASKA AROUND MID AFTERNOON. THEN THE PICTURE GETS MORE COMPLEX
AS THE AFTERNOON WEARS ON. THE NAM/HRRR SHOW ANOTHER FOCUS FOR
CONVERGENCE JUST EAST OF THE LARAMIE RANGE NEAR WHEATLAND AND
TORRINGTON. IF THIS SECONDARY AREA OF CONVERGENCE GETS
GOING....THE SEVERE WEATHER MAY SPREAD FURTHER NORTH AND WEST.
SHEAR IS QUITE STRONG FOR THIS TIME OF YEAR WITH 0-6KM VALUES OF
40 TO 50 KTS AND SURFACE BASED CAPES OF 2000 TO 3000J/KG. THESE
CONVERGENT BOUNDARIES COULD ALSO SERVE AS A FOCUS FOR TORNADOS
ESPECIALLY IF WE GET GOOD STRETCHING FROM THE STEEP LOW LEVEL
LAPSE RATES. AT THIS POINT...WE WOULD SAY THAT THE BEST SHOT FOR
SUPERCELLS PRODUCING LARGE HAIL...DAMAGING WINDS AND POSSIBLY
ISOLATED TORNADOS WOULD BE SOUTH OF A TORRINGTON TO ALLIANCE LINE
WITH THE RIGHT MOVERS GENERALLY MOVING EAST-SOUTHEAST. IF STORMS
GET GOING FURTHER NORTH THEY WILL GENERALLY LIFT NORTHEAST WITH
THE MAIN THREATS BEING GUSTY WINDS AND SMALL HAIL.
THIS EVENING:
ONGOING SEVERE WEATHER WILL BE POSSIBLE IN THE PANHANDLE. MEANWHILE...
THE MODELS ARE ADVERTISING A MID LEVEL SHORTWAVE MOVING THROUGH AREAS
WEST OF THE LARAMIE RANGE. THE DEEPER MOISTURE IS ALSO PROGGED TO
MOVE INTO THIS REGION DURING THAT TIME. NOT EXPECTING MUCH IN THE
WAY OF SEVERE WEATHER WITH THIS WAVE...BUT IT COULD BRING A GOOD
SHOT OF BENEFICIAL RAINFALL TO AREAS WEST OF THE LARAMIE RANGE
WHERE WILDFIRES HAVE BEEN PRESENT. THE RAIN SHOULD DIMINISH BY
MIDNIGHT OR SO AND MAY DISSIPATE AS IT CROSSES OVER THE LARAMIE
RANGE.
SATURDAY-SATURDAY NIGHT:
THE MAIN UPPER LEVEL WAVE IS PROGGED TO LIFT NORTHEAST TOWARDS
NORTHWEST WYOMING DURING THE MORNING AND THEN PUSH THROUGH NORTHERN
WYOMING AND SOUTHERN MONTANA DURING THE AFTERNOON AND EARLY EVENING.
THE TRACK OF THIS WAVE IS STILL A BIT UNCERTAIN...BUT IT IS VERY
DYNAMIC...SO WE DID INCREASE THE CHANCES OF PRECIP A BIT ACROSS
OUR NORTHERN COUNTIES SATURDAY AND SATURDAY EVENING. THIS AREA MAY
ALSO SEE A STRONG/SEVERE STORMS DUE TO GOOD SHEAR AND DECENT
INSTABILITY. NOT AS CONFIDENT ABOUT THE CONVECTION CHANCES CLOSER
TO I-80...BUT IF THERE IS ENOUGH MOISTURE PRESENT WE WOULD NOT BE
SURPRISED TO SEE A FEW STORMS DEVELOP OVER THE MOUNTAINS.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 400 AM MDT FRI AUG 7 2015
THE 00Z MEDIUM RANGE MODELS CONCUR THAT THE UPPER RIDGE WILL REBUILD
OVER THE ROCKY MOUNTAINS LATE SUNDAY AND EXTEND INTO THE GREAT PLAINS
THROUGH THE MIDDLE OF NEXT WEEK WHILE A UPPER LOW AND ASSOCIATED TROUGH
IMPACTS THE FAR WEST. NORMALLY THIS IS A STABLE PATTERN WITH WARM
TEMPERATURES ALOFT QUASHING DIURNAL CONVECTION. WHILE MOST OF THE
MONSOON MOISTURE WILL BE CHANNELED BETWEEN THE RIDGE AND TROUGH TO
THE WEST...THE ECMWF AND GFS INDICATE SOME MONSOON MOISTURE TRYING
TO INFILTRATE THE RIDGE. OROGRAPHIC LIFT AND THIS MOISTURE MAY RESULT
IN ISOLATED AFTERNOON TSTORM ACTIVITY OVER THE HIGHER TERRAIN OF
SOUTHEAST WY. OTHERWISE...MOST OF THE CWA WILL REMAIN DRY WITH
TEMPERATURES GRADUALLY WARMING EACH DAY. OTHER THAN THE TYPICAL
BREEZES EACH AFTERNOON...WINDS SHOULD NOT BE A PROBLEM FOR FIRE
WEATHER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1231 PM MDT FRI AUG 7 2015
MAIN AVIATION CONCERN FOR THIS TAF CYCLE WILL BE SHOWERS AND
THUNDERSTORMS EXPECTED TO DEVELOP THIS AFTERNOON AND CONTINUE AT
TIMES THRU SATURDAY. A SFC BOUNDARY HAS SET UP ROUGHLY FROM
CHEYENNE TO ALLIANCE...WITH SOUTHWEST WINDS IN A RATHER MOIST
ENVIRONMENT EAST OF THIS BOUNDARY. STILL EXPECT STORMS TO FIRE
ALONG THIS BOUNDARY AND TRAVEL NORTHEAST...WITH MVFR/IFR
CONDITIONS IN MODERATE TO HEAVY RAIN...STRONG WINDS...AND HAIL
POSSIBLE OUT OF A FEW STRONGER STORMS. ELSEWHERE...ISOLATED TO
SCATTERED SHOWERS AND STORMS ARE LIKELY AS WELL THROUGH TONIGHT
BUT SHOULD CARRY LESS IMPACT TO TERMINALS.
&&
.FIRE WEATHER...
ISSUED AT 400 AM MDT FRI AUG 7 2015
MONSOON MOISTURE WILL BE ON THE INCREASE TODAY IN RESPONSE TO AN UPPER
LEVEL DISTURBANCE MOVING NORTHEAST FROM THE DESERT SOUTHWEST. ALONG
WITH THE INCREASING MOISTURE...SHOWERS AND THUNDERSTORMS WILL BE A
GOOD POSSIBILITY ESPECIALLY IN THE NEBRASKA PANHANDLE THIS AFTERNOON
AND EVENING...AS WELL AS SOME BENEFICIAL RAINFALL MOVING INTO AREAS
WEST OF THE LARAMIE RANGE DURING THE EVENING. OVERALL...WIND SPEEDS
SHOULD ALSO BE LIGHTER TODAY...BUT THEY WILL BE GUSTY AND ERRATIC
NEAR THUNDERSTORMS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...REC
LONG TERM...MAJ
AVIATION...RJM
FIRE WEATHER...REC
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
414 AM MDT FRI AUG 7 2015
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 400 AM MDT FRI AUG 7 2015
THE MAIN CONCERN WITH THIS PORTION OF THE FORECAST IS THE POTENTIAL
FOR SEVERE CONVECTION THIS AFTERNOON/EVENING IN THE NEBRASKA PANHANDLE
AND THE POTENTIAL FOR RAIN AND THUNDERSTORMS ACROSS AREAS WEST OF
THE LARAMIE RANGE THIS EVENING.
TODAY AND TONIGHT:
LATEST WATER VAPOR LOOP WAS SHOWING A FAIRLY STRONG SHORTWAVE
MOVING THROUGH CENTRAL CALIFORNIA. AHEAD OF THIS FEATURE...THERE
IS A GOOD FETCH OF MOISTURE FROM THE PACIFIC WITH THE BULK OF THIS
MOISTURE STILL IN NEVADA AND UTAH. MEANWHILE...IN THE HIGH PLAINS
OF NORTHEAST COLORADO AND THE SOUTHERN PANHANDLE THE SURFACE
OBSERVATIONS ARE SHOWING QUITE A POOL OF LOW LEVEL MOISTURE WITH
DEWPOINTS IN THE 60S. SURFACE ANALYSIS IS ALREADY SHOWING THE LEE
TROUGH DEVELOPING IN RESPONSE TO THE SHORTWAVE IN CALIFORNIA.
PIECES OF ENERGY EJECTING AHEAD OF THIS SHORTWAVE COULD SET THE
STAGE FOR AN ACTIVE SEVERE WEATHER DAY ACROSS THE HIGH PLAINS OF
NEBRASKA AND PORTIONS OF SOUTHEAST WYOMING. THE MAIN QUESTION WILL
BE THE LOCATION OF THE BEST LOW LEVEL CONVERGENCE. THE HRRR IS
SHOWING THE INITIAL BOUNDARY SITUATED FROM KIMBALL TO ALLIANCE
NEBRASKA AROUND MID AFTERNOON. THEN THE PICTURE GETS MORE COMPLEX
AS THE AFTERNOON WEARS ON. THE NAM/HRRR SHOW ANOTHER FOCUS FOR
CONVERGENCE JUST EAST OF THE LARAMIE RANGE NEAR WHEATLAND AND
TORRINGTON. IF THIS SECONDARY AREA OF CONVERGENCE GETS
GOING....THE SEVERE WEATHER MAY SPREAD FURTHER NORTH AND WEST.
SHEAR IS QUITE STRONG FOR THIS TIME OF YEAR WITH 0-6KM VALUES OF
40 TO 50 KTS AND SURFACE BASED CAPES OF 2000 TO 3000J/KG. THESE
CONVERGENT BOUNDARIES COULD ALSO SERVE AS A FOCUS FOR TORNADOS
ESPECIALLY IF WE GET GOOD STRETCHING FROM THE STEEP LOW LEVEL
LAPSE RATES. AT THIS POINT...WE WOULD SAY THAT THE BEST SHOT FOR
SUPERCELLS PRODUCING LARGE HAIL...DAMAGING WINDS AND POSSIBLY
ISOLATED TORNADOS WOULD BE SOUTH OF A TORRINGTON TO ALLIANCE LINE
WITH THE RIGHT MOVERS GENERALLY MOVING EAST-SOUTHEAST. IF STORMS
GET GOING FURTHER NORTH THEY WILL GENERALLY LIFT NORTHEAST WITH
THE MAIN THREATS BEING GUSTY WINDS AND SMALL HAIL.
THIS EVENING:
ONGOING SEVERE WEATHER WILL BE POSSIBLE IN THE PANHANDLE. MEANWHILE...
THE MODELS ARE ADVERTISING A MID LEVEL SHORTWAVE MOVING THROUGH AREAS
WEST OF THE LARAMIE RANGE. THE DEEPER MOISTURE IS ALSO PROGGED TO
MOVE INTO THIS REGION DURING THAT TIME. NOT EXPECTING MUCH IN THE
WAY OF SEVERE WEATHER WITH THIS WAVE...BUT IT COULD BRING A GOOD
SHOT OF BENEFICIAL RAINFALL TO AREAS WEST OF THE LARAMIE RANGE
WHERE WILDFIRES HAVE BEEN PRESENT. THE RAIN SHOULD DIMINISH BY
MIDNIGHT OR SO AND MAY DISSIPATE AS IT CROSSES OVER THE LARAMIE
RANGE.
SATURDAY-SATURDAY NIGHT:
THE MAIN UPPER LEVEL WAVE IS PROGGED TO LIFT NORTHEAST TOWARDS
NORTHWEST WYOMING DURING THE MORNING AND THEN PUSH THROUGH NORTHERN
WYOMING AND SOUTHERN MONTANA DURING THE AFTERNOON AND EARLY EVENING.
THE TRACK OF THIS WAVE IS STILL A BIT UNCERTAIN...BUT IT IS VERY
DYNAMIC...SO WE DID INCREASE THE CHANCES OF PRECIP A BIT ACROSS
OUR NORTHERN COUNTIES SATURDAY AND SATURDAY EVENING. THIS AREA MAY
ALSO SEE A STRONG/SEVERE STORMS DUE TO GOOD SHEAR AND DECENT
INSTABILITY. NOT AS CONFIDENT ABOUT THE CONVECTION CHANCES CLOSER
TO I-80...BUT IF THERE IS ENOUGH MOISTURE PRESENT WE WOULD NOT BE
SURPRISED TO SEE A FEW STORMS DEVELOP OVER THE MOUNTAINS.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 400 AM MDT FRI AUG 7 2015
THE 00Z MEDIUM RANGE MODELS CONCUR THAT THE UPPER RIDGE WILL REBUILD
OVER THE ROCKY MOUNTAINS LATE SUNDAY AND EXTEND INTO THE GREAT PLAINS
THROUGH THE MIDDLE OF NEXT WEEK WHILE A UPPER LOW AND ASSOCIATED TROUGH
IMPACTS THE FAR WEST. NORMALLY THIS IS A STABLE PATTERN WITH WARM
TEMPERATURES ALOFT QUASHING DIURNAL CONVECTION. WHILE MOST OF THE
MONSOON MOISTURE WILL BE CHANNELED BETWEEN THE RIDGE AND TROUGH TO
THE WEST...THE ECMWF AND GFS INDICATE SOME MONSOON MOISTURE TRYING
TO INFILTRATE THE RIDGE. OROGRAPHIC LIFT AND THIS MOISTURE MAY RESULT
IN ISOLATED AFTERNOON TSTORM ACTIVITY OVER THE HIGHER TERRAIN OF
SOUTHEAST WY. OTHERWISE...MOST OF THE CWA WILL REMAIN DRY WITH
TEMPERATURES GRADUALLY WARMING EACH DAY. OTHER THAN THE TYPICAL
BREEZES EACH AFTERNOON...WINDS SHOULD NOT BE A PROBLEM FOR FIRE
WEATHER.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 400 AM MDT FRI AUG 7 2015
VFR CONDITIONS WILL PREVAIL OUTSIDE TSTORM ACTIVITY. TSTORMS WILL
INITIALLY FORM LATE THIS MORNING OVER THE MOUNTAINS...WITH ADDITIONAL
DEVELOPMENT ACROSS THE PLAINS DURING THE AFTERNOON. THE MAIN HAZARDS
WILL BE HAIL AND STRONG WIND GUSTS...AS WELL AS MVFR OR LOWER VSBY
UNDER THE HEAVIER SHOWERS. TSTORMS WILL LINGER THROUGH TONIGHT OVER
WESTERN NE PANHANDLE AND WEST OF THE LARAMIE RANGE.
&&
.FIRE WEATHER...
ISSUED AT 400 AM MDT FRI AUG 7 2015
MONSOON MOISTURE WILL BE ON THE INCREASE TODAY IN RESPONSE TO AN UPPER
LEVEL DISTURBANCE MOVING NORTHEAST FROM THE DESERT SOUTHWEST. ALONG
WITH THE INCREASING MOISTURE...SHOWERS AND THUNDERSTORMS WILL BE A
GOOD POSSIBILITY ESPECIALLY IN THE NEBRASKA PANHANDLE THIS AFTERNOON
AND EVENING...AS WELL AS SOME BENEFICIAL RAINFALL MOVING INTO AREAS
WEST OF THE LARAMIE RANGE DURING THE EVENING. OVERALL...WIND SPEEDS
SHOULD ALSO BE LIGHTER TODAY...BUT THEY WILL BE GUSTY AND ERRATIC
NEAR THUNDERSTORMS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...REC
LONG TERM...MAJ
AVIATION...MAJ
FIRE WEATHER...REC
AREA FORECAST DISCUSSION...UPDATE FOR AVIATION
NWS LITTLE ROCK AR
1240 AM CDT SUN AUG 9 2015
.AVIATION...
OVERALL VFR FLIGHT CONDITIONS ARE EXPECTED OVER THE NEXT 24 HOURS.
PATCHY MVFR MAY DEVELOP TOWARD SUNDAY MORNING...BUT COVERAGE IS
EXPECTED TO REMAIN LOW. AN ISOLATED SHOWER OR THUNDERSTORM MAY
DEVELOP BUT COVERAGE WILL BE VERY LOW AND DID NOT INCLUDE IN TAFS.
WINDS WILL BE LIGHT AND VARIABLE OVER CENTRAL AREAS...WHILE LIGHT
FROM THE SOUTH OVER SOUTHERN AR...SW TO SE AT 3 TO 9 MPH OVER
NORTHERN AR. VFR CONDITIONS ARE EXPECTED ON SUNDAY WITH OVERALL A
SOUTH WIND FLOW.
&&
.PREV DISCUSSION... /ISSUED 304 PM CDT SAT AUG 8 2015/
SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT
A FEW ISOLATED SHOWERS AND THUNDERSTORMS HAVE POPPED UP ACROSS THE
STATE DURING THE LAST COUPLE OF HOURS AND THESE HAVE BEEN EXTREMELY
ISOLATED IN NATURE. WITH A STALLED BOUNDARY ACROSS THE STATE...DO
EXPECT A FEW MORE SHOWERS AND THUNDERSTORMS TO POP UP IN THE HEAT OF
THE DAY...WHICH THE HRRR HAS BEEN CONSISTENT IN SHOWING AS WELL.
SUNDAY WILL BE SLIGHTLY HOTTER AS THE RIDGE BUILDS INTO THE
AREA...THE AXIS OF HIGHEST DEW POINTS WILL SHIFT A BIT MORE TO THE
EAST. AS A RESULT...THIS WILL ADD NE ARKANSAS INTO THE HEAT ADVISORY.
A HOT DAY CAN BE EXPECTED ON MONDAY AS WELL WITH SLIGHTLY LOWER DEW
POINTS. AT THIS POINT IT APPEARS THE ONLY AREAS ABLE TO REACH
EXCESSIVE HEAT WARNING CRITERIA WILL BE ACROSS SE PORTIONS OF THE
CWA...BUT AT THIS POINT ITS BORDERLINE. WILL DEFER TO THE MID
SHIFT...AS THE NUMBERS ARE SO CLOSE TO CRITERIA. A FRONT WILL MOVE
THROUGH THE STATE ON MONDAY...WITH LITTLE IN THE WAY OF
PRECIPITATION EXPECTED UNTIL THE FRONT REACHES SOUTHERN ARKANSAS. IT
CONTINUES TO LOOK THAT THE BEST CHANCES FOR PRECIPITATION WILL BE TO
THE SOUTH OF THE STATE...BUT DID GO AND INCLUDE SLIGHT CHANCE POPS
ACROSS SOUTHERN PORTIONS OF THE STATE.
LONG TERM...WEDNESDAY THROUGH FRIDAY
SOME EXCESSIVE HEAT RELIEF IS IN STORE BEGINNING WEDNESDAY. AS
THE UPPER RIDGE SHIFTS WEST ALLOWING AND IN THE WAKE OF A WEAK
COLD FRONT MAX TEMPS DURING THIS PERIOD WILL RUN AT OR BELOW
NORMAL. DRIER CONDITIONS AS WELL AS DEWPOINTS FALL INTO THE UPPER
50S TO MID 60S. LOOKS TO BE A DRY PERIOD AS STABLE NORTHERLY FLOW
ALOFT AND WEAK NE SURFACE FLOW DOMINATE AND EMBEDDED UPPER LEVEL
DISTURBANCES SEEM UNLIKELY AT THIS TIME.
&&
.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR 74 99 79 98 / 0 0 10 20
CAMDEN AR 77 104 78 103 / 0 0 10 10
HARRISON AR 74 97 74 94 / 0 0 10 20
HOT SPRINGS AR 78 103 78 102 / 0 0 10 10
LITTLE ROCK AR 77 103 80 102 / 0 0 10 10
MONTICELLO AR 77 103 80 103 / 0 0 10 10
MOUNT IDA AR 75 102 74 102 / 0 0 10 10
MOUNTAIN HOME AR 74 98 75 96 / 0 0 10 20
NEWPORT AR 73 98 77 96 / 0 0 10 20
PINE BLUFF AR 76 103 78 101 / 0 0 10 10
RUSSELLVILLE AR 76 101 75 101 / 0 0 10 10
SEARCY AR 73 100 76 98 / 0 0 10 20
STUTTGART AR 75 101 77 99 / 0 0 10 20
&&
.LZK WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR BAXTER-BOONE-
CLEBURNE-INDEPENDENCE-JACKSON-MARION-MONROE-NEWTON-SEARCY-STONE-
VAN BUREN-WOODRUFF.
HEAT ADVISORY FROM 11 AM TO 8 PM CDT SUNDAY FOR BAXTER-BOONE-
CLEBURNE-FULTON-INDEPENDENCE-IZARD-JACKSON-MARION-NEWTON-SEARCY-
SHARP-STONE-VAN BUREN.
EXCESSIVE HEAT WARNING UNTIL 8 PM CDT THIS EVENING FOR ARKANSAS-
BRADLEY-CALHOUN-CLARK-CLEVELAND-CONWAY-DALLAS-DESHA-DREW-
FAULKNER-GARLAND-GRANT-HOT SPRING-JEFFERSON-JOHNSON-LINCOLN-
LOGAN-LONOKE-MONTGOMERY-OUACHITA-PERRY-PIKE-POLK-POPE-PRAIRIE-
PULASKI-SALINE-SCOTT-WHITE-YELL.
EXCESSIVE HEAT WARNING FROM 11 AM TO 8 PM CDT SUNDAY FOR
ARKANSAS-BRADLEY-CALHOUN-CLARK-CLEVELAND-CONWAY-DALLAS-DESHA-
DREW-FAULKNER-GARLAND-GRANT-HOT SPRING-JEFFERSON-JOHNSON-LINCOLN-
LOGAN-LONOKE-MONROE-MONTGOMERY-OUACHITA-PERRY-PIKE-POLK-POPE-
PRAIRIE-PULASKI-SALINE-SCOTT-WHITE-WOODRUFF-YELL.
HEAT ADVISORY FROM 11 AM TO 8 PM CDT MONDAY FOR ARKANSAS-BRADLEY-
CALHOUN-CLARK-CLEBURNE-CLEVELAND-CONWAY-DALLAS-DESHA-DREW-
FAULKNER-GARLAND-GRANT-HOT SPRING-JACKSON-JEFFERSON-JOHNSON-
LINCOLN-LOGAN-LONOKE-MONROE-MONTGOMERY-OUACHITA-PERRY-PIKE-POLK-
POPE-PRAIRIE-PULASKI-SALINE-SCOTT-VAN BUREN-WHITE-WOODRUFF-YELL.
&&
$$
AVIATION...51
AREA FORECAST DISCUSSION
NWS TAUNTON MA
139 AM EDT SUN AUG 9 2015
.SYNOPSIS...
HIGH PRESSURE WILL MAINTAIN DRY WEATHER THROUGH SUN AS LOW
PRESSURE REMAINS WELL OFFSHORE...THOUGH A SPOT SHOWER IS POSSIBLE
ACROSS THE INTERIOR SUN AFTERNOON. LOW PRESSURE WILL RESULT IN
SCATTERED SHOWERS AND THUNDERSTORMS AT TIMES MON NIGHT INTO WED
MORNING. A TREND TOWARD DRIER WEATHER IS LIKELY THROUGH THE
REMAINDER OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
10 PM UPDATE...
LITTLE ADDITIONAL CHANGES NECESSARY WITH THIS UPDATE. IN SPITE OF
THE CLOUD COVER SEVERAL LOCATIONS ARE ALREADY MAKING A RUN INTO
THE MID 60S. DWPTS ACROSS THE REGION ARE AS LOW AS THE LOW-MID
50S SO THERE IS MORE ROOM TO DROP THROUGH THE OVERNIGHT HOURS.
THEREFORE...DID LOWER MINS BY A BIT...BUT THAT WAS THE ONLY REAL
CHANGE.
315 PM UPDATE...
PLENTY OF DIURNAL CU ACROSS INTERIOR WHERE HRRR AND 12Z NAM WANT
TO BRING SOME ISOLATED SHOWER ACTIVITY THIS AFTERNOON. COLUMN IS
FAIRLY DRY SO AM NOT BUYING INTO THAT...MODELS ARE MORE LIKELY
INDICATING BUILDING CU WHICH IS EVIDENT ON SATELLITE NEAR
BERKSHIRES.
MEANWHILE COASTAL LOW IS THROWING BACK SOME PATCHY MID AND HIGH
CLOUDS ALONG S COAST...CAPE COD AND ISLANDS. EXPECT THESE CLOUDS
TO THICKEN UP TONIGHT BUT NO RAIN EXPECTED AS BEST LIFT STAYS
OFFSHORE WITH PROGRESSIVE UPPER FLOW. SOME OF HIGH-RES MODELS
/HRRR...RAP AND ARW-WRF/ WANT TO BRING RAINFALL TO SE NEW ENGLAND
LATER TONIGHT BUT THAT LOOKS TO BE OVERDONE.
ANOTHER PLEASANTLY COOL NIGHT AHEAD WITH GOOD RADIATIONAL COOLING
CONDITIONS AWAY FROM INFLUENCE OF MID/HIGH CLOUDS NEAR S COAST.
LEANED TOWARD COOLER GFS LAMP GUIDANCE WHICH BRINGS LOWS INTO
UPPER 40S ACROSS NW MA AND MAINLY 50S ELSEWHERE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM MONDAY/...
EXPECTING A GOOD AMOUNT OF CLOUDINESS NEAR CAPE COD AND ISLANDS
SUN DUE TO INCREASING NE FLOW ON PERIPHERY OF COASTAL LOW. MODEL
CROSS SECTIONS SHOW GOOD AMOUNT OF LOW LEVEL MOISTURE BELOW 950 MB
WHICH SHOULD BECOME TRAPPED. NO REAL MECHANISM FOR RAINFALL SO DRY
WEATHER ANTICIPATED AS DEEPER MOISTURE AND LIFT REMAIN WELL
OFFSHORE. SOME QUESTION AS TO WHETHER OR NOT LOW CLOUDS WILL BREAK
DURING AFTERNOON...BUT FOR NOW LEANED TOWARD THEM HANGING ON.
ACROSS INTERIOR...MODELS CONTINUE TO HINT AT POSSIBILITY OF FEW
SHOWERS BY AFTERNOON DUE TO SUBTLE LIFT FROM UPPER TROUGH. LOW
LEVEL CONVERGENCE IS MINIMAL DUE TO WEAK WIND FIELDS...SO ANY
ACTIVITY WOULD BE TIED TO TERRAIN. STABILITY PARAMETERS MARGINAL
SO EXPECT AN ISOLATED SHOWER OR PERHAPS A THUNDERSTORM ACROSS NW
AND POSSIBLY N CENTRAL MA.
HIGHS SHOULD BE A LITTLE COOLER THAN TODAY...ESPECIALLY NEAR COAST
DUE TO NE FLOW AND CLOUDINESS...RANGING FROM AROUND 70 ON OUTER
CAPE TO AROUND 80 FARTHER INLAND.
SUBSIDENCE AND SOME DRYING SUN NIGHT SHOULD LEAD TO AT LEAST
PARTIAL CLEARING...BUT CONTINUED ONSHORE FLOW MAY KEEP CLOUDS
LOCKED IN CLOSER TO COAST. LOWS SHOULD DROP BACK INTO 50S AND
LOWER 60S.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
HIGHLIGHTS...
* UNSETTLED WEATHER LIKELY LATE MON NIGHT THROUGH WED MORNING
* TEMPS SLIGHTLY BELOW NORMAL FOR MUCH OF THE WEEK
* POSSIBLE RETURN TO AUGUST HEAT FOR SATURDAY
OVERALL...MODELS ARE IN DECENT AGREEMENT THROUGH MUCH OF THE LONG
TERM. THERE ARE A COUPLE OF DISCREPANCIES THAT CONTINUE THROUGH THE
PERIOD. AS FAR AS SENSIBLE WEATHER GOES...THE MODELS ARE IN
AGREEMENT. LOOKING AT AN UPPER LEVEL TROUGH IN THE GREAT LAKES
MONDAY SLOWLY MOVING EASTWARD OVER THE NORTHEAST AND NEW ENGLAND BY
WEDNESDAY AND POTENTIALLY STALLING THERE THROUGH THE END OF THE
FORECAST PERIOD. THE ECMWF KEEPS THE PATTERN MORE AMPLIFIED...WHILE
THE GFS HAS A FLATTER FLOW AT THE MID-LEVELS WITH THE TROUGH
RETREATING INTO SOUTHEASTERN CANADA.
THIS TROUGH RESULTS IN LOW PRESSURE DEVELOPING IN THE GREAT LAKES
AND MOVING INTO QUEBEC TUESDAY. THE ECMWF PRODUCES A TRIPLE POINT
LOW OVER NEW JERSEY OFF THE MAIN LOW IN QUEBEC AND TRANSLATES THE
TRIPLE POINT LOW ALONG THE SOUTHERN NEW ENGLAND COAST. THE GFS
DEPICTS NO SUCH REDEVELOPMENT BUT KEEPS A STRONG SOUTHERLY FLOW
AHEAD OF THE COLD FRONT EXTENDING FROM THE QUEBEC LOW. THESE
DIFFERENCES COULD AFFECT THE OVERALL NATURE OF THE RAIN /WHETHER ITS
MORE STRATIFORM OR SHOWERY/ BUT REGARDLESS OF THE NATURE OR THE TYPE
OF SYSTEM...TUESDAY IS LIKELY TO BE WET. MODELS HINT THAT THE RAIN
COULD MOVE INTO OUR WESTERN ZONES LATE MONDAY NIGHT INTO EARLY
TUESDAY MORNING...BUT THE BULK OF THE RAIN APPEARS TO HOLD OFF TIL
AFTER 12Z TUESDAY. RAIN CONTINUES THROUGH TUESDAY INTO THE FIRST
PART OF THE DAY ON WEDNESDAY BUT THEN WILL TAPER OFF AS EITHER THE
FRONT MOVES THROUGH OR THE LOW PRESSURE EJECTS TOWARDS THE MARITIMES.
THE REMAINDER OF THE WEEK LOOKS TO BE DRY WITH A POSSIBILITY OF A
FEW DIURNAL SHOWERS HERE AND THERE EACH DAY. TEMPERATURES ARE
EXPECTED TO BE BELOW TO NEAR NORMAL UNTIL THE WEEKEND WHEN DEPENDING
ON THE MODEL COULD SEE A RETURN TO AUGUST HEAT AND HUMIDITY.
&&
.AVIATION /05Z SUNDAY THROUGH THURSDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
THROUGH TODAY...HIGH CONFIDENCE.
VFR EXPECTED INLAND OF THE CAPE AND ISLANDS. CAPE/ISLAND TERMINALS
WILL SEE SOME MVFR CIGS LATER THIS MORNING AND CONTINUING INTO THE
EARLY AFTERNOON BEFORE DISSIPATING. A SPRINKLE MIGHT ACCOMPANY
THESE LOWER CLOUDS.
OTHERWISE DRY INLAND...BUT A SPOT SHOWER IS POSSIBLE IN THE HIGHER
TERRAIN DURING THE AFTERNOON HOURS.
TONIGHT INTO MON...HIGH CONFIDENCE.
MAINLY VFR. DIURNAL CU EXPECTED AGAIN MON. ALTHOUGH WINDS MAY LEAN
SLIGHTLY E OF N...SEA BREEZES ARE LIKELY DURING THE DAY MON.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.
OUTLOOK /MONDAY NIGHT THROUGH THURSDAY/...
TUESDAY...MODERATE CONFIDENCE. MVFR/IFR CONDITIONS LIKELY IN
WIDESPREAD RAIN/FOG.
WEDNESDAY...MODERATE CONFIDENCE. LINGERING MVFR/IFR CONDITIONS IN
DEPARTING RAIN. IMPROVING CONDITIONS THROUGH THE DAY.
THURSDAY...MODERATE CONFIDENCE. MAINLY VFR. LOW PROBABILITY OF
BRIEF MVFR CONDITIONS IN DIURNAL -SHRA.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
HIGH CONFIDENCE THROUGH SUN NIGHT.
DROPPED SCA ON OUTER S COASTAL WATERS WHERE SEAS HAVE SUBSIDED.
LIGHT N/NE WINDS GIVE WAY TO INCREASING NE WINDS SUN AND
ESPECIALLY SUN NIGHT...AS LOW PRESSURE PASSES WELL SE OF NEW
ENGLAND. SEAS SHOULD BEGIN TO BUILD LATER IN DAY AND COULD REACH 5
FT BY SUN NIGHT E AND S OF NANTUCKET...WHICH MAY REQUIRE SCA IN
LATER FORECASTS. DRY WEATHER EXPECTED THROUGH PERIOD.
OUTLOOK /MONDAY THROUGH THURSDAY/...
MONDAY...HIGH CONFIDENCE. WINDS AND SEAS DIMINISH AS HIGH PRESSURE
BUILDS OVER THE WATERS.
TUESDAY...MODERATE CONFIDENCE. WINDS AND SEAS INCREASE AS EITHER A
COLD FRONT OR A LOW PRESSURE SYSTEM MOVE OVER THE WATERS. SMALL
CRAFT ADVISORIES WILL LIKELY BE NEEDED FOR SEAS IF NOT WINDS AS
WELL. VISIBILITIES MAY BE LIMITED AT TIMES IN RAIN.
WEDNESDAY...MODERATE CONFIDENCE. WINDS AND SEAS DIMINISH AS LOW
PRESSURE PULLS AWAY FROM SOUTHERN NEW ENGLAND.
THURSDAY...MODERATE CONFIDENCE. QUIET BOATING WEATHER EXPECTED.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...RLG/JWD
NEAR TERM...DOODY/JWD
SHORT TERM...JWD
LONG TERM...RLG
AVIATION...DOODY/RLG
MARINE...RLG/JWD
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
231 AM CDT SUN AUG 9 2015
.SHORT TERM...
320 PM CDT
THROUGH SUNDAY...
MAIN CONCERN IS WITH CONVECTIVE POTENTIAL LATE TONIGHT INTO
SUNDAY. RAOBS AND AIRCRAFT SOUNDINGS TODAY SHOWED AN ENVIRONMENT
HOSTILE TO PRECIP MAINTENANCE. THEREFORE DESPITE SOME FORCING FROM
A CONVECTIVELY INDUCED SHORTWAVE OVERHEAD...LIGHT RADAR ECHOES
OVER AREA ARE LIKELY VIRGA AND HAVE PULLED MENTION OF SPRINKLES
THE REST OF TODAY. CONVERGENT AXIS IN FRONTAL ZONE OF DISSIPATING
WEAK LOW OVER SOUTHERN LAKE MICHIGAN DID INITIATIVE SOME
CONVECTION OVER NORTH CENTRAL INDIANA...AND WOULD EXPECT FURTHER
DEVELOPMENT TO REMAIN EAST OF THE CWA. OVERALL...WITH PLENTY OF
CLOUD COVER WELL BACK TO THE WEST...INCLUDING PATCHY LOWER CLOUDS
IN SPOTS...JUST EXPECTING A MOSTLY CLOUDY REST OF THE DAY INTO
TONIGHT. VERY WEAK GRADIENT WILL YIELD LIGHT/CALM WINDS OVERNIGHT
AND LOW DEWPOINT SPREADS COULD SET STAGE FOR SOME PATCHY FOG OR
HAZE. LOW TEMPS WILL BE IN THE MID 60S TO AROUND 70.
FOCUS LATE TONIGHT INTO SUNDAY WILL BE ON MCS EXPECTED TO DEVELOP
OVER EASTERN NEBRASKA AND WESTERN IOWA THIS EVENING. MCS IS LIKELY
TO RIDE ALONG INSTABILITY AXIS THAT WILL MAINLY BE SOUTH OF THE
CWA OFF TO THE EAST-SOUTHEAST INTO SUNDAY MORNING. CONSENSUS OF
MODEL GUIDANCE IS TO KEEP INSTABILITY MINIMAL AT BEST FOR MUCH OF
THE CWA...LIMITING THUNDER POTENTIAL. CANNOT COMPLETELY RULE OUT
THUNDER GIVEN MODEST LOW LEVEL JET/WAA REGIME. RECENT HI-RES
CAMS...INCLUDING 4KM NAM AND EXPERIMENTAL HRRR DEPICT A REASONABLE
SCENARIO IN WHICH STRATIFORM NORTH OF MCS OVERSPREADS MUCH OF CWA
FROM WESTNORTHWEST TO EAST SOUTHEAST AFTER MIDNIGHT THROUGH MID
SUNDAY MORNING/BY WHICH TIME IT WILL PROBABLY BE DECAYING. HAVE
FOCUSED CATEGORICAL POPS INTO SOUTHERN CWA WHERE CONFIDENCE IS
HIGHEST IN WIDESPREAD COVERAGE. ITS POSSIBLE FAR NORTHEAST CWA
COULD SEE LITTLE OR NO RAIN. BEST CHANCE FOR HEAVY DOWNPOURS LOOKS
TO BE IN FAR SOUTHERN CWA WHERE MORE ROBUST CONVECTION COULD PASS
THROUGH...THOUGH ANY THREAT FOR STRONG TO SEVERE STORMS SHOULD
STAY SOUTHWEST OF THE CWA GIVEN ANTICIPATED DECAYING TREND OF MCS.
A GOOD DEAL OF UNCERTAINTY THE REMAINDER OF SUNDAY REGARDING
CONVECTIVE TRENDS. A SURFACE LOW LOOKS TO EVOLVE EASTWARD INTO THE
MID MISSISSIPPI VALLEY BY LATER IN THE DAY...WITH RETURN FLOW AND
WEST-SOUTHWEST LLJ ALSO DEVELOPING. LINGERING CLOUD COVER WILL
LIMIT DESTABILIZATION AND THUNDER POTENTIAL...ESPECIALLY FARTHER
NORTH UNTIL LATE DAY. ANOTHER SHORTWAVE WILL APPROACH FROM WEST IN
LATE AFTERNOON AND THERE SHOULD BE ENOUGH 925-850 MB MOISTURE
CONVERGENCE TO SUPPORT CHANCE POPS NORTH OF I-80 AND LIKELIESSOUTH
OF I-80. MODERATE WESTERLY MIDLEVEL FLOW WILL RESULT IN 30-40 KT
OF WEST-NORTHWEST 0-6KM SHEAR. THIS WILL SUPPORT SOME THREAT FOR
STRONG TO SEVERE STORMS WELL SOUTH OF I-80 CLOSER TO EXPECTED
TRACK OF SFC LOW AND WHERE TEMPS AROUND 80 AND LOW-MID 70S
DEWPOINTS COULD BRING SLIGHTLY BETTER INSTABILITY. MAIN THREAT
WOULD BE GUSTY TO DAMAGING WINDS...AS HAIL APPEARS UNLIKELY WITH
700-500 MB LAPSE RATES LESS THAN 6 CELSIUS PER KM. SUNDAY OVERALL
WILL BE A CLOUDY AND MUGGY DAY...WITH HIGHS IN THE MID 70S TO
AROUND 80.
RC
&&
.LONG TERM...
320 PM CDT
SUNDAY NIGHT THROUGH SATURDAY...
THE BEST CHANCE FOR PRECIP IN THE EXTENDED WILL BE SUNDAY EVENING
THROUGH MONDAY AFTERNOON...WITH VERY SLIGHT CHANCES OF PRECIP LATE
NEXT WEEK.
A COMPLEX OF STORMS WILL BE DIMINISHING OVER THE REGION SUNDAY
EVENING AND NIGHT. THE UPPER LEVEL VORTICITY PATTERN IS VERY CHAOTIC
WITH GUIDANCE INDICATING THE MAIN MCV WILL BE OVER CENTRAL IL AND
VORT STREAMERS ASSOCIATED WITH THE UPPER LEVEL TROUGH WILL BE OVER
WISCONSIN. WITH SUCH A MESSY PATTERN...DECIDED TO ONLY MAKE MINOR
ADJUSTMENTS TO PRECIP CHANCES SUNDAY NIGHT. HAVE A CHANCE OF
THUNDERSTORMS ALONG AND EAST OF I-39 WITH BETTER CHANCES EAST OF I-
55. COULD SEE A FEW STRONG TO SEVERE STORMS SOUTH OF I-80 BUT
CONDITIONS WILL BE WEAKENING AS THE EVENING PROGRESSES.
OVERALL...HAVE LOW CONFIDENCE IN EXACTLY HOW SUNDAY NIGHT WILL PLAY
OUT DUE TO SO MANY MESOSCALE FEATURES AND WHETHER OR NOT THE
ATMOSPHERE WILL BE ABLE TO RECOVER FROM SUNDAY MORNING/S STORMS.
A SHORT WAVE MOVING WITH THE UPPER LEVEL TROUGH ROTATES THROUGH
MONDAY WITH A DECENT VORTICITY STREAMER. WENT WITH A CHANCE OF
SHOWERS AND STORMS MAINLY NORTH OF I-80 MONDAY. THINKING THE NAM IS
ONCE AGAIN TOO MOIST LEADING TO TOO MUCH CONVECTIVE DEVELOPMENT.
THINKING SHOWERS AND STORMS WILL DRIFT SOUTH OF THE IL/WI STATE LINE
MONDAY AFTERNOON AND THEN WEAKEN AS THEY CONTINUE TO SHIFT SOUTH
MONDAY EVENING. MONDAY EVENING MAY END UP BEING DRY...BUT DID NOT
HAVE ENOUGH CONFIDENCE IN A DRY FORECAST SO KEPT A SLIGHT CHANCE OF
SHOWERS AND STORMS ALONG AND SOUTH OF I-80 MONDAY EVENING.
THE UPPER LEVEL TROUGH AXIS SHIFTS EAST THROUGH WISCONSIN WITH
COOLER UPPER LEVEL AIR SINKING SOUTH THROUGH THE REGION. HIGH
PRESSURE THEN BUILDS IN FOR WEDNESDAY AND THURSDAY LEADING TO DRY
CONDITIONS THROUGH THURSDAY. HIGH TEMPS TUESDAY WILL BE AROUND
80...THEN IN THE UPPER 70S WEDNESDAY. LAKE BREEZES BOTH DAYS WILL
KEEP LOCATIONS ALONG THE LAKE IN THE MID 70S. TEMPS REBOUND INTO
THE LOW TO MID 80S THURSDAY WITH NO LAKE COOLING.
THE NEXT LOW PRESSURE SYSTEM MOVES OVER JAMES BAY THURSDAY EVENING
AND PUSHES THE HIGH PRESSURE SOUTH OVER THE OHIO VALLEY. THE LOWS
COLD FRONT SINKS SOUTH OVER FAR NORTHERN IL FRIDAY AFTERNOON SO HAVE
A SLIGHT CHANCE TO CHANCE OF SHOWERS AND STORMS.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* SHORT PERIOD OF MVFR CEILINGS IN THE NEAR TERM...MAINLY FOR
ORD.
* PERIOD OF RAIN LIKELY THIS MORNING...POSSIBLY WITH MVFR VIS.
* CHANCE OF SHOWERS AGAIN LATER IN THE DAY...ISOLATED THUNDER
POSSIBLE BUT MORE LIKELY SOUTH OF TERMINALS.
* LOW CEILINGS BECOMING LIKELY LATER TODAY WITH MVFR LIKELY...AND
POSSIBLY IFR.
RODRIGUEZ
//DISCUSSION...UPDATED 06Z...
BULK OF ANY PRECIP ACTIVITY REMAINING TO THE WEST OF THE TERMINALS
EARLY THIS MORNING...WHILE GENERALLY VFR CONDITIONS IN PLACE.
HOWEVER...SOME ISOLATED MVFR CEILINGS ARE REMAIN AROUND THE
TERMINALS AND WHILE FOG IS DEVELOPING ACROSS THE AREA. FOG WILL
LIKELY REMAIN THROUGH THE MORNING WHILE THE PRECIP OVER THE
IOWA/ILLINOIS BORDER SLOWLY SHIFTS EAST. TRYING TO GET A TIME OF
ARRIVAL ON THE LEADING EDGE...BUT EASTERN EDGE CONTINUES TO ERODE.
HAVE MAINTAINED SIMILAR TIMING TO PREVIOUS FORECAST...WITH SHORT
TERM GUIDANCE LIKEWISE SUPPORTING THIS TIMING. STILL FEEL GOOD
WITH KEEPING THUNDER OUT OF THE TAFS AS INSTABILITY IS TO THE
WEST/SOUTH OF THE TERMINALS. AS THIS PUSHES THROUGH THIS
MORNING...UPSTREAM DEVELOPMENT WILL PROVIDE ADDITIONAL CHANCES FOR
PRECIP LATER THIS AFTERNOON INTO EARLY EVENING. HAVE MAINTAINED
SIMILAR START TIMES AND EVEN KEPT THUNDER OUT OF THE TAFS...WITH
THE EXCEPTION OF GYY WHERE A SLIGHTLY HIGHER CHANCE WILL RESIDE.
DID LOWER CEILINGS THOUGH LATER THIS AFTERNOON INTO THE EVENING AS
ITS APPEARING POSSIBLE THAT A PERIOD OF LOW STRATUS WILL SET
UP...ALTHOUGH CONFIDENCE IS LOW WITH REGARD TO HOW LOW CEILINGS
WILL GET. SURFACE WIND FIELD THIS MORNING THROUGH THIS EVENING
LOOKS TO BE HIGHLY VARIABLE WITH A WEAK SURFACE PATTERN AND THEN
APPROACHING SYSTEM...BUT SPEEDS STILL LOOK TO REMAIN UNDER 10 KT.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE WITH CEILINGS IN THE NEAR TERM.
* MEDIUM IN RAIN COVERAGE/TIMING AND MVFR POTENTIAL THIS MORNING.
* MEDIUM-LOW IN WINDS TODAY...THOUGH SHOULD BE GENERALLY LESS
THAN 10 KTS.
* LOW IN SHRA/ISOLATED TSRA COVERAGE SUNDAY AFTERNOON/EVE.
* HIGH WITH MVFR CEILINGS LATER TODAY...LOW ON IFR.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...
MONDAY...CHANCE OF SHRA/TSRA AND MVFR. NORTH-NORTHEAST WINDS.
TUESDAY AND WEDNESDAY...VFR. NORTHEAST WINDS.
THURSDAY...VFR. WEST-SOUTHWEST WINDS.
FRIDAY...SLIGHT CHANCE TSRA. WEST-SOUTHWEST WINDS.
RATZER
&&
.MARINE...
230 AM CDT
HIGHLY VARIABLE WIND FIELD ACROSS THE LAKE THIS MORNING AS A
WEAKER SURFACE PATTERN IN PLACE...WITH HIGH PRESSURE SITUATED TO
THE EAST AND NORTHEAST. THESE VARIABLE WINDS WILL LIKELY PERSIST
ACROSS THE NORTHERN HALF OF THE LAKE TODAY WHILE THE SOUTHERN END
BECOMES MORE SOUTHERLY THIS MORNING...AS LOW PRESSURE SLOWLY MOVES
EAST TOWARDS THE REGION. AS THIS THIS LOW CONTINUES EAST NORTHEAST
TO THE SOUTHERN END OF THE LAKE AND A SEPARATE LOW OVER ONTARIO
MOVES EAST TO HUDSON BAY TONIGHT...WINDS WILL LIKELY CONTINUE TO
BE VARIABLE ACROSS THE LAKE. HOWEVER...IT DOES APPEAR THAT SPEEDS
WILL STAY ON THE LIGHTER SIDE THROUGH THIS PERIOD. THIS LOW WILL
THEN MOVE TO THE EASTERN LAKES MONDAY INTO MONDAY NIGHT AS HIGH
PRESSURE TO THE NORTHWEST BEGINS SPREADING SOUTHEAST...WITH
NORTHERLY WINDS SETTING UP ACROSS THE ENTIRE LAKE. AS THE SURFACE
GRADIENT TIGHTENS UP OVER THE LAKE LATE MONDAY AND MONDAY
NIGHT...NORTHERLY SPEEDS WILL BEGIN TO INCREASE. THIS INCREASING
TREND WITH THE NORTHERLY WINDS CONTINUES TUESDAY WITH 15 TO 25 KT
WINDS BECOMING LIKELY DURING THIS TIME.
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
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WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
100 AM CDT SUN AUG 9 2015
.SHORT TERM...
320 PM CDT
THROUGH SUNDAY...
MAIN CONCERN IS WITH CONVECTIVE POTENTIAL LATE TONIGHT INTO
SUNDAY. RAOBS AND AIRCRAFT SOUNDINGS TODAY SHOWED AN ENVIRONMENT
HOSTILE TO PRECIP MAINTENANCE. THEREFORE DESPITE SOME FORCING FROM
A CONVECTIVELY INDUCED SHORTWAVE OVERHEAD...LIGHT RADAR ECHOES
OVER AREA ARE LIKELY VIRGA AND HAVE PULLED MENTION OF SPRINKLES
THE REST OF TODAY. CONVERGENT AXIS IN FRONTAL ZONE OF DISSIPATING
WEAK LOW OVER SOUTHERN LAKE MICHIGAN DID INITIATIVE SOME
CONVECTION OVER NORTH CENTRAL INDIANA...AND WOULD EXPECT FURTHER
DEVELOPMENT TO REMAIN EAST OF THE CWA. OVERALL...WITH PLENTY OF
CLOUD COVER WELL BACK TO THE WEST...INCLUDING PATCHY LOWER CLOUDS
IN SPOTS...JUST EXPECTING A MOSTLY CLOUDY REST OF THE DAY INTO
TONIGHT. VERY WEAK GRADIENT WILL YIELD LIGHT/CALM WINDS OVERNIGHT
AND LOW DEWPOINT SPREADS COULD SET STAGE FOR SOME PATCHY FOG OR
HAZE. LOW TEMPS WILL BE IN THE MID 60S TO AROUND 70.
FOCUS LATE TONIGHT INTO SUNDAY WILL BE ON MCS EXPECTED TO DEVELOP
OVER EASTERN NEBRASKA AND WESTERN IOWA THIS EVENING. MCS IS LIKELY
TO RIDE ALONG INSTABILITY AXIS THAT WILL MAINLY BE SOUTH OF THE
CWA OFF TO THE EAST-SOUTHEAST INTO SUNDAY MORNING. CONSENSUS OF
MODEL GUIDANCE IS TO KEEP INSTABILITY MINIMAL AT BEST FOR MUCH OF
THE CWA...LIMITING THUNDER POTENTIAL. CANNOT COMPLETELY RULE OUT
THUNDER GIVEN MODEST LOW LEVEL JET/WAA REGIME. RECENT HI-RES
CAMS...INCLUDING 4KM NAM AND EXPERIMENTAL HRRR DEPICT A REASONABLE
SCENARIO IN WHICH STRATIFORM NORTH OF MCS OVERSPREADS MUCH OF CWA
FROM WESTNORTHWEST TO EAST SOUTHEAST AFTER MIDNIGHT THROUGH MID
SUNDAY MORNING/BY WHICH TIME IT WILL PROBABLY BE DECAYING. HAVE
FOCUSED CATEGORICAL POPS INTO SOUTHERN CWA WHERE CONFIDENCE IS
HIGHEST IN WIDESPREAD COVERAGE. ITS POSSIBLE FAR NORTHEAST CWA
COULD SEE LITTLE OR NO RAIN. BEST CHANCE FOR HEAVY DOWNPOURS LOOKS
TO BE IN FAR SOUTHERN CWA WHERE MORE ROBUST CONVECTION COULD PASS
THROUGH...THOUGH ANY THREAT FOR STRONG TO SEVERE STORMS SHOULD
STAY SOUTHWEST OF THE CWA GIVEN ANTICIPATED DECAYING TREND OF MCS.
A GOOD DEAL OF UNCERTAINTY THE REMAINDER OF SUNDAY REGARDING
CONVECTIVE TRENDS. A SURFACE LOW LOOKS TO EVOLVE EASTWARD INTO THE
MID MISSISSIPPI VALLEY BY LATER IN THE DAY...WITH RETURN FLOW AND
WEST-SOUTHWEST LLJ ALSO DEVELOPING. LINGERING CLOUD COVER WILL
LIMIT DESTABILIZATION AND THUNDER POTENTIAL...ESPECIALLY FARTHER
NORTH UNTIL LATE DAY. ANOTHER SHORTWAVE WILL APPROACH FROM WEST IN
LATE AFTERNOON AND THERE SHOULD BE ENOUGH 925-850 MB MOISTURE
CONVERGENCE TO SUPPORT CHANCE POPS NORTH OF I-80 AND LIKELIESSOUTH
OF I-80. MODERATE WESTERLY MIDLEVEL FLOW WILL RESULT IN 30-40 KT
OF WEST-NORTHWEST 0-6KM SHEAR. THIS WILL SUPPORT SOME THREAT FOR
STRONG TO SEVERE STORMS WELL SOUTH OF I-80 CLOSER TO EXPECTED
TRACK OF SFC LOW AND WHERE TEMPS AROUND 80 AND LOW-MID 70S
DEWPOINTS COULD BRING SLIGHTLY BETTER INSTABILITY. MAIN THREAT
WOULD BE GUSTY TO DAMAGING WINDS...AS HAIL APPEARS UNLIKELY WITH
700-500 MB LAPSE RATES LESS THAN 6 CELSIUS PER KM. SUNDAY OVERALL
WILL BE A CLOUDY AND MUGGY DAY...WITH HIGHS IN THE MID 70S TO
AROUND 80.
RC
&&
.LONG TERM...
320 PM CDT
SUNDAY NIGHT THROUGH SATURDAY...
THE BEST CHANCE FOR PRECIP IN THE EXTENDED WILL BE SUNDAY EVENING
THROUGH MONDAY AFTERNOON...WITH VERY SLIGHT CHANCES OF PRECIP LATE
NEXT WEEK.
A COMPLEX OF STORMS WILL BE DIMINISHING OVER THE REGION SUNDAY
EVENING AND NIGHT. THE UPPER LEVEL VORTICITY PATTERN IS VERY CHAOTIC
WITH GUIDANCE INDICATING THE MAIN MCV WILL BE OVER CENTRAL IL AND
VORT STREAMERS ASSOCIATED WITH THE UPPER LEVEL TROUGH WILL BE OVER
WISCONSIN. WITH SUCH A MESSY PATTERN...DECIDED TO ONLY MAKE MINOR
ADJUSTMENTS TO PRECIP CHANCES SUNDAY NIGHT. HAVE A CHANCE OF
THUNDERSTORMS ALONG AND EAST OF I-39 WITH BETTER CHANCES EAST OF I-
55. COULD SEE A FEW STRONG TO SEVERE STORMS SOUTH OF I-80 BUT
CONDITIONS WILL BE WEAKENING AS THE EVENING PROGRESSES.
OVERALL...HAVE LOW CONFIDENCE IN EXACTLY HOW SUNDAY NIGHT WILL PLAY
OUT DUE TO SO MANY MESOSCALE FEATURES AND WHETHER OR NOT THE
ATMOSPHERE WILL BE ABLE TO RECOVER FROM SUNDAY MORNING/S STORMS.
A SHORT WAVE MOVING WITH THE UPPER LEVEL TROUGH ROTATES THROUGH
MONDAY WITH A DECENT VORTICITY STREAMER. WENT WITH A CHANCE OF
SHOWERS AND STORMS MAINLY NORTH OF I-80 MONDAY. THINKING THE NAM IS
ONCE AGAIN TOO MOIST LEADING TO TOO MUCH CONVECTIVE DEVELOPMENT.
THINKING SHOWERS AND STORMS WILL DRIFT SOUTH OF THE IL/WI STATE LINE
MONDAY AFTERNOON AND THEN WEAKEN AS THEY CONTINUE TO SHIFT SOUTH
MONDAY EVENING. MONDAY EVENING MAY END UP BEING DRY...BUT DID NOT
HAVE ENOUGH CONFIDENCE IN A DRY FORECAST SO KEPT A SLIGHT CHANCE OF
SHOWERS AND STORMS ALONG AND SOUTH OF I-80 MONDAY EVENING.
THE UPPER LEVEL TROUGH AXIS SHIFTS EAST THROUGH WISCONSIN WITH
COOLER UPPER LEVEL AIR SINKING SOUTH THROUGH THE REGION. HIGH
PRESSURE THEN BUILDS IN FOR WEDNESDAY AND THURSDAY LEADING TO DRY
CONDITIONS THROUGH THURSDAY. HIGH TEMPS TUESDAY WILL BE AROUND
80...THEN IN THE UPPER 70S WEDNESDAY. LAKE BREEZES BOTH DAYS WILL
KEEP LOCATIONS ALONG THE LAKE IN THE MID 70S. TEMPS REBOUND INTO
THE LOW TO MID 80S THURSDAY WITH NO LAKE COOLING.
THE NEXT LOW PRESSURE SYSTEM MOVES OVER JAMES BAY THURSDAY EVENING
AND PUSHES THE HIGH PRESSURE SOUTH OVER THE OHIO VALLEY. THE LOWS
COLD FRONT SINKS SOUTH OVER FAR NORTHERN IL FRIDAY AFTERNOON SO HAVE
A SLIGHT CHANCE TO CHANCE OF SHOWERS AND STORMS.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* SHORT PERIOD OF MVFR CEILINGS IN THE NEAR TERM...MAINLY FOR
ORD.
* PERIOD OF RAIN LIKELY THIS MORNING...POSSIBLY WITH MVFR VIS.
* CHANCE OF SHOWERS AGAIN LATER IN THE DAY...ISOLATED THUNDER
POSSIBLE BUT MORE LIKELY SOUTH OF TERMINALS.
* LOW CEILINGS BECOMING LIKELY LATER TODAY WITH MVFR LIKELY...AND
POSSIBLY IFR.
RODRIGUEZ
//DISCUSSION...UPDATED 06Z...
BULK OF ANY PRECIP ACTIVITY REMAINING TO THE WEST OF THE TERMINALS
EARLY THIS MORNING...WHILE GENERALLY VFR CONDITIONS IN PLACE.
HOWEVER...SOME ISOLATED MVFR CEILINGS ARE REMAIN AROUND THE
TERMINALS AND WHILE FOG IS DEVELOPING ACROSS THE AREA. FOG WILL
LIKELY REMAIN THROUGH THE MORNING WHILE THE PRECIP OVER THE
IOWA/ILLINOIS BORDER SLOWLY SHIFTS EAST. TRYING TO GET A TIME OF
ARRIVAL ON THE LEADING EDGE...BUT EASTERN EDGE CONTINUES TO ERODE.
HAVE MAINTAINED SIMILAR TIMING TO PREVIOUS FORECAST...WITH SHORT
TERM GUIDANCE LIKEWISE SUPPORTING THIS TIMING. STILL FEEL GOOD
WITH KEEPING THUNDER OUT OF THE TAFS AS INSTABILITY IS TO THE
WEST/SOUTH OF THE TERMINALS. AS THIS PUSHES THROUGH THIS
MORNING...UPSTREAM DEVELOPMENT WILL PROVIDE ADDITIONAL CHANCES FOR
PRECIP LATER THIS AFTERNOON INTO EARLY EVENING. HAVE MAINTAINED
SIMILAR START TIMES AND EVEN KEPT THUNDER OUT OF THE TAFS...WITH
THE EXCEPTION OF GYY WHERE A SLIGHTLY HIGHER CHANCE WILL RESIDE.
DID LOWER CEILINGS THOUGH LATER THIS AFTERNOON INTO THE EVENING AS
ITS APPEARING POSSIBLE THAT A PERIOD OF LOW STRATUS WILL SET
UP...ALTHOUGH CONFIDENCE IS LOW WITH REGARD TO HOW LOW CEILINGS
WILL GET. SURFACE WIND FIELD THIS MORNING THROUGH THIS EVENING
LOOKS TO BE HIGHLY VARIABLE WITH A WEAK SURFACE PATTERN AND THEN
APPROACHING SYSTEM...BUT SPEEDS STILL LOOK TO REMAIN UNDER 10 KT.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE WITH CEILINGS IN THE NEAR TERM.
* MEDIUM IN RAIN COVERAGE/TIMING AND MVFR POTENTIAL THIS MORNING.
* MEDIUM-LOW IN WINDS TODAY...THOUGH SHOULD BE GENERALLY LESS
THAN 10 KTS.
* LOW IN SHRA/ISOLATED TSRA COVERAGE SUNDAY AFTERNOON/EVE.
* HIGH WITH MVFR CEILINGS LATER TODAY...LOW ON IFR.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...
MONDAY...CHANCE OF SHRA/TSRA AND MVFR. NORTH-NORTHEAST WINDS.
TUESDAY AND WEDNESDAY...VFR. NORTHEAST WINDS.
THURSDAY...VFR. WEST-SOUTHWEST WINDS.
FRIDAY...SLIGHT CHANCE TSRA. WEST-SOUTHWEST WINDS.
RATZER
&&
.MARINE...
320 PM CDT
HIGH PRESSURE STRETCHES FROM QUEBEC THROUGH THE OHIO VALLEY WHILE
LOW PRESSURE IS OVER MANITOBA. BOTH SYSTEMS WILL SHIFT EAST WITH THE
LOW REACHING JAMES BAY BY MONDAY MORNING. AS SUCH LIGHT NORTHEAST
WINDS BECOME SOUTH TO SOUTHEAST SUNDAY. THE TROUGH ASSOCIATED WITH
THE LOWS COLD/STATIONARY FRONT SHIFTS THROUGH LATE SUNDAY NIGHT INTO
MONDAY MORNING WITH WINDS BECOMING NORTH BEHIND IT. A WEAK CLOSED
LOW FORMS OVER THE EASTERN GREAT LAKES MONDAY EVENING AND DEEPENS AS
IT SHIFTS NORTHEAST. AT THE SAME TIME HIGH PRESSURE WILL BE PUSHING
EAST OVER THE WESTERN GREAT LAKES. THIS WILL LEAD TO NORTH WINDS
INCREASING TO 10 TO 20 KT MONDAY NIGHT THROUGH TUESDAY NIGHT. WINDS
WEAKEN WEDNESDAY WITH THE HIGH OVERHEAD...AND THEN BACK TO SOUTHWEST
AS THE HIGH IS PUSHED SOUTH BY THE NEXT LOW OVER JAMES BAY THURSDAY.
JEE
&&
.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
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AREA FORECAST DISCUSSION
NWS LINCOLN IL
1104 PM CDT SAT AUG 8 2015
.UPDATE...
ISSUED AT 835 PM CDT SAT AUG 8 2015
WEAK SURFACE WIND SHIFT STILL DEPICTED ON THE LASTEST SURFACE
ANALYSIS OVER PARTS OF EAST CENTRAL THROUGH SOUTH CENTRAL IL
EARLY THIS EVENING. HAD A FEW LIGHT SHOWERS DEVELOP ALONG IT
EARLIER BUT NOT MUCH SINCE THEN. A BAND OF MID LEVEL CLOUDS
AND OCCASIONAL LIGHT SHOWERS STRETCHED FROM EAST CENTRAL IOWA
INTO PARTS OF CENTRAL ILLINOIS. THE STRONGER LOW LEVEL WARM
ADVECTION AND MOISTURE CONVERGENCE IS WELL OUT WEST OF OUR
AREA OVER THE MISSOURI RIVER VALLEY WHERE JUST RECENTLY CONVECTION
HAS FINALLY DEVELOPED OVER FAR SOUTHEAST NEBRASKA. THAT AREA
SHOULD INCREASE IN COVERAGE AS IT PUSHES EAST LATE THIS EVENING
WITH OUR AREA SEEING THE BULK OF THE SHOWERS AND STORMS DURING
THE MORNING HOURS OF SUNDAY. PRECIPITABLE WATER VALUES OF OVER
2 INCHES NOTED OVER PARTS OF SOUTHEAST NEBRASKA INTO WESTERN IOWA
WITH FORECAST MODELS SUGGESTING SIMILAR VALUES AS THE CONVECTIVE
SYSTEM ARRIVES IN OUR AREA EARLY SUNDAY MORNING. RAINFALL AMOUNTS
OF 1 TO 2 INCHES WILL BE POSSIBLE OVER PARTS OF WEST CENTRAL IL
BY SUNDAY MORNING WITH SOME OF THE MORE INTENSE THUNDERSTORMS.
HAVE MADE SOME MINOR ADJUSTMENTS TO THE GRIDS WITH RESPECT TO
TIMING OF THE MORE WIDESPREAD SHOWERS AND STORMS LATE TONIGHT AND
ADDED SOME LIGHTER SHOWERS FURTHER SOUTH AND EAST TO TAKE INTO
ACCOUNT THE WIDELY SCATTERED SHOWERS NOW OCCURRING WITH SOME OF
THE MID LEVEL CLOUDS TRACKING ESE ACROSS THE REGION THIS EVE.
SHOULD HAVE THE UPDATED ZONES OUT BY 900 PM.
&&
.SHORT TERM...(TONIGHT)
ISSUED AT 307 PM CDT SAT AUG 8 2015
REMNANTS OF AN MCS OVER EASTERN MO AT MID AFTERNOON HAS ISOLATED
LIGHT SHOWERS AND SPRINKLES OVER CENTRAL IL WEST OF I-57 AND
DRIFTING EASTWARD. MOST OF OUR AREA SHOULD STAY DRY INTO THIS
EVENING WITH JUST A FEW LIGHT SHOWERS OR SPRINKLES POSSIBLE OVER
PARTS OF CENTRAL IL WITH PARTLY TO MOSTLY CLOUDY SKIES. ANOTHER MCS
WILL LIKELY DEVELOP OVER WESTERN IA AND FAR EASTERN NEBRASKA ON NOSE
OF AN 35-45 KT 850 MB SW JET THIS EVENING AND TRACK ESE ACROSS IA
AND EVENTUALLY INTO CENTRAL IL DURING OVERNIGHT. 4KM WRF AND TAIL
END OF HRRR MODEL SHOWS MOST OF CONVECTION SREADING EAST TOWARD IL
RIVER VALLEY BETWEEN 08Z-10Z AND APPROACHING I-57 AROUND 12Z.
CONTINUED MENTION OF HEAVY RAIN FROM PEORIA NW LATE TONIGHT AFTER
09Z/4 AM WITH QPF OVERNIGHT HALF TO THREE QUARTER INCHES AND LOCALLY
1 INCH FROM GALESBURG AND MACOMB WEST. SPC HAS MARGINAL RISK OF
SEVERE STORMS OVERNIGHT WEST OF PEORIA AND SPRINGFIELD FOR GUSTY
WINDS AND SMALL HAIL WHILE SLIGHT RISK OF SEVERE IS FROM QUINCY
WESTWARD ACROSS NORTHERN MO AND SOUTHERN IA. SE IL/WABASH RIVER
VALLEY WILL LIKELY STAY DRY MOST OF TONIGHT AND PATCHY FOG COULD
FORM OVERNIGHT IN FAR SOUTHEAST IL WHERE LESS CLOUD COVER. MUGGY
LOWS TONIGHT IN THE UPPER 60S AND LOWER 70S WHICH IS CLOSE TO
CURRENT DEWPOINTS AND LIGHT WINDS TONIGHT.
.LONG TERM...(SUNDAY THROUGH SATURDAY)
ISSUED AT 307 PM CDT SAT AUG 8 2015
A THUNDERSTORM COMPLEX/MCS IS EXPECTED TO TRACK EASTWARD ACROSS
ILLINOIS SUNDAY MORNING...LIKELY WEAKENING THROUGH THE DAYTIME.
ALTHOUGH STILL WAITING FOR THIS SYSTEM TO DEVELOP AROUND EASTERN
NB/WESTERN IA THIS EVENING...RECENT TRENDS HAVE BEEN FOR SIMILAR
SYSTEMS TO DEVELOP SLIGHTLY SOUTHWARD FROM EARLY FORECASTS...AND
LATEST MODEL RUNS HINT AT THIS AS WELL. THEREFORE...HAVE TRENDED
HEAVIER PRECIPITATION AMOUNTS A BIT SOUTHWARD FROM PREVIOUS PACKAGE
WITH AMOUNTS FROM AROUND 1 TO 1.5 INCHES POSSIBLE NORTH OF I-72 AND
WEST OF I-55 BY NOON SUNDAY...WITH THE HIGHER END OF THAT RANGE MORE
LIKELY TOWARD THE GALESBURG AREA. LOWER AMOUNTS AND LOWER
PRECIPITATION CHANCES EXPECTED WITH THIS SYSTEM SOUTH OF I-72 TOWARD
THE EFFINGHAM/I-70 AREA.
A BIT OF A BREAK IN THUNDERSTORM ACTIVITY LIKELY FOR MIDDAY SUNDAY
AS THE OVERNIGHT SYSTEM MOVES OFF TO THE EAST. EXACT TIMING...CLOUD
COVER LEFT BEHIND...AND BOUNDARIES LEFT BEHIND FROM THE OVERNIGHT
SYSTEM WILL IMPACT THE POSSIBILITY OF ANOTHER THUNDERSTORM COMPLEX
DEVELOPING SUNDAY NIGHT. CURRENT MODEL CONSENSUS FORMS THIS FARTHER
SOUTH TOWARD THE OHIO VALLEY AREA AND HAVE TRENDED PRECIP CHANCES
TOWARD THAT AREA FOR SUNDAY NIGHT INTO MONDAY.
AFTER THAT...UPPER RIDGING WILL BUILD OVER THE CENTRAL CONUS AND
DEEP TROUGHING WILL DEVELOP DOWNSTREAM ACROSS THE GREAT LAKES/OHIO
RIVER VALLEY. AS A RESULT...MUCH OF THE EXTENDED BEYOND MONDAY IS
COOL/DRY. GFS/ECMWF SHOW THE NEXT FRONTAL BOUNDARY DROPPING INTO
THE GREAT LAKES AREA JUST NORTH OF CENTRAL IL FRIDAY. HOWEVER...BOTH
LARGELY DISSIPATE THE FEATURE AND WILL MENTION JUST A SLIGHT CHANCE
POP ACROSS THE NORTHERN HALF OF THE CWA ON FRIDAY UNTIL BETTER MODEL
CONSISTENCY IS ACHIEVED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1100 PM CDT SAT AUG 8 2015
AREA OF SHOWERS AND THUNDERSTORMS WAS BEGINNING TO INCREASE IN
COVERAGE ACROSS IOWA AND SHOULD CONTINUE TO PUSH EAST INTO OUR
AREA OVERNIGHT AND THRU MOST OF SUNDAY MORNING. THE MAIN FORECAST
CONCERN WILL BE AFFECT ON CIGS/VSBYS ACROSS THE TAF SITES INTO
EARLY SUNDAY AFTERNOON. WITH THE ONSET OF THE MORE SIGNIFICANT
RAINS AND TSRA AFTER 08Z...IT APPEARS MOST AREAS WILL EXPERIENCE
A DROP TO MVFR AND OCCASIONALLY IFR CIGS. THAT SHOULD CONTINUE
INTO EARLY AFTERNOON AND AS THE SYSTEM SHIFTS OFF TO OUR EAST...
WE SHOULD THEN SEE A GRADUAL IMPROVEMENT IN CIGS ACROSS THE
AREA. SOME OF THE SHORT TERM FORECAST MODELS NOW SUGGESTING
THE POTENTIAL FOR A BAND OF LOW LEVEL CLOUDS (1000-2000 FEET)
MAY AFFECT CMI AND BMI IN THE 05-08Z TIME FRAME BEFORE THE
MORE WIDESPREAD RAINS AND THUNDER ARRIVE. RIGHT NOW WILL
INTRODUCE A SCATTERED GROUP AT 600-1000 FEET AT BOTH SITES.
SURFACE WINDS WILL ONCE AGAIN BE A NON-FACTOR...UNLESS ONE OF THE
TAF SITES IS AFFECTED BY A STRONGER THUNDERSTORM LATE TONIGHT.
THEN WE COULD SEE SOME GUSTY WINDS WITH A VARIABLE DIRECTION.
OTHERWISE...AN EAST TO SOUTHEAST DIRECTION WILL PREVAIL TONIGHT
INTO SUNDAY MORNING AT 5 TO 10 KTS...AND THEN VEER MORE INTO A
SOUTHERLY DIRECTION BY AFTERNOON WITH AGAIN SPEEDS OF 10 KTS
OR LESS.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SMITH
SHORT TERM...07
LONG TERM...ONTON
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS GOODLAND KS
250 AM MDT SUN AUG 9 2015
.SHORT TERM...(THIS AFTERNOON THROUGH SUNDAY)
ISSUED AT 229 PM MDT SAT AUG 8 2015
EARLY AFTERNOON WV IMAGERY AND RAP H5 ANALYSIS SHOWS 595 DM RIDGE
ACROSS SOUTHERN PLAINS WITH PLUME OF PACIFIC MOISTURE STREAMING INTO
THE CENTRAL ROCKIES AND ACROSS OUR CWA. SEVERAL WEAK
RIPPLES/SHORTWAVE TROUGHS WITHIN THE H5/H7 SW FLOW ARE UPSTREAM OF
THE REGION WITH SOME ENHANCEMENT ACROSS THE HIGHER TERRAIN IN THE
CENTRAL AND SOUTHERN ROCKIES. AT THE SURFACE LOW PRESSURE EXTENDS
ACROSS EASTERN COLORADO AND SOUTHWEST KANSAS. STATIONARY/WARM
FRONT IS CURRENTLY JUST OVER THE SOUTHEAST PORTIONS OF OUR CWA.
THIS AFTERNOON-TONIGHT...BAROCLINIC ZONE EXTENDING ACROSS SE CWA AND
ACROSS EASTERN COLORADO WILL ACT AS FOCUS FOR INITIATION NEAR OUR CWA
AS HEIGHT FALLS AND INCREASING ISENTROPIC ASCENT MOVES SOUTH OF
INTERSTATE 70. STRONGEST PRECIP SIGNAL IS ALONG STATIONARY FRONT IN
THE SOUTH...ESPECIALLY BY ARW/HRRR. RAP ANALYSIS SHOWS CAPE VALUES
ALREADY AROUND 4000 J/KG IN THE SOUTHEAST...WITH EFFECTIVE BULK
SHEER VALUES IN EXCESS OF 40KT. WHILE THERE IS SOME LOW LEVEL
VEERING...OVERALL SEVERE INDICES FAVOR DAMAGING WINDS AND LARGE
HAIL WITH ON A SMALL THREAT FOR TORNADOS WITHIN PROXIMITY TO MAIN
TROUGH AXIS. VERY MOIST AIR MASS...THE POSSIBILITY FOR BACKBUILDING
ALONG FRONTAL ZONE...AND STORM MOTIONS GENERALLY LESS THAN 20KT WILL
TEND TO SUPPORT POTENTIAL FOR LOCALIZED FLASH FLOODING. HI RES
GUIDANCE IS INDICATING POTENTIAL FOR THUNDERSTORMS TO FORM INTO ONE
OR SEVERAL SMALL MCS CLUSTERS ACROSS THE SOUTHERN PART OF THE
FORECAST AREA. EARLIER GUIDANCE WAS SHOWING THIS SPREADING AS FAR
NORTH AS THE I-70 CORRIDOR.
WITH LINGERING WAA ACROSS THE SE CWA...ALONG WITH SEVERAL MORE
WEAK SHORTWAVES PASSING THROUGH THE REGION...SE PORTIONS OF THE
FORECAST AREA COULD CONTINUE TO SEE SHOWER/THUNDERSTORM ACTIVITY
LINGER THROUGH SUNDAY MORNING. TREND WILL BE FOR DECREASING
INSTABILITY...SO SEVERE THREAT SHOULD BE LIMITED TO JUST THE
EVENING HOURS. VERY MOIST AIR MASS AND LIGHT WINDS WILL ALSO TEND
TO SUPPORT POTENTIAL FOR FOG/STRATUS TO REDEVELOP BY SUNRISE.
SUNDAY...WITH WEAK FORCING AND LINGERING FRONT IN OUR SE...THERE
WILL BE THE POTENTIAL FOR SHOWERS/THUNDERSTORMS THROUGH MIDDAY. NAM
SHOWS INCREASING FORCING BY LATE MORNING EARLY AFTERNOON AS A
STRONGER TROUGH DIGS INTO THE NORTHERN PLAINS. OTHER GUIDANCE IS NOT
QUITE AS FAR SOUTH...PRIMARILY FAVORS THE SOUTHER PARTS OF OUR CWA
FOR BEST THUNDERSTORM CHANCES. THERE SHOULD BE ENOUGH
INSTABILITY/SHEER IN THE AFTERNOON TO SUPPORT AT LEAST A FEW MORE
ORGANIZED THUNDERSTORMS. LOW CONFIDENCE IN HI TEMP FORECAST AS (LIKE
TODAY) TEMPS WILL BE HIGHLY DEPENDENT ON STRATUS CLEARING AND TIMING
OF THUNDERSTORM ACTIVITY. THE AIR MASS ADVERTISED OVER THE CWA WITH
AVERAGE MIXING WOULD SUPPORT SEASONAL HIGHS IN THE UPPER 80S/LOWER
90S.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 248 AM MDT SUN AUG 9 2015
AN UPPER LEVEL RIDGE WILL CONTINUE TO BE IN PLACE OVER THE TRI STATE
AREA TO START OFF THE LONG TERM PERIOD WEDNESDAY. THE CENTRAL AREA
OF HIGH PRESSURE WILL REMAIN OVER THE ROCKY MOUNTAIN RANGE AND THE
CENTRAL PLAINS WEDNESDAY. WITH THE PRESENCE OF THE UPPER
RIDGE...JET AREAS AND POCKETS OF VORTICITY WILL REMAIN WELL AWAY
FROM THE TRI STATE AREA...WHICH WILL BRING UPPER STABILITY FOR THE
REST OF THE FORECAST PERIOD.
AT THE SURFACE...MAINLY SOUTHERLY FLOW WILL ADVECT WARM MOIST AIR
INTO THE HIGH PLAINS WITH A BIT OF AN UPSLOPE COMPONENT AS WINDS ARE
SOMEWHAT SOUTHEASTERLY. GFS/ECMWF MODEL SOUNDINGS SHOW PRECIPITABLE
WATER VALUES BETWEEN 1 AND 1.5 INCHES OVER THE TRI STATE AREA WITH
SOME CAPE IN THE PROFILE THAT WOULD BE CONDUCIVE TO STEADY RAINFALL
PRODUCTION. WITH CAP VIA MODEL SOUNDINGS APPEARING CLOSE TO BEING
ABLE TO BREAK DUE TO SURFACE HEATING DESPITE A LACK OF STRONG
SURFACE AND UPPER LEVEL FORCING...CHANCES FOR SHOWERS AND
THUNDERSTORMS ARE POSSIBLE WEDNESDAY EVENING MAINLY FOR SOUTH OF
INTERSTATE 70 ALONG THE SURFACE TROUGH AND A WEAK DRY LINE
FEATURE.
CHANCES FOR AFTERNOON SHOWERS AND THUNDERSTORMS ARE ALSO POSSIBLE
HEADING INTO THURSDAY...FRIDAY AND SATURDAY WITH A WEAK QUASI
STATIONARY SURFACE DEFORMATION ZONE INDICATED BY THE GFS/ECMWF
SURFACE FORECASTS. CURRENTLY THINKING THE BEST CHANCE FOR STORMS
WILL BE IN EASTERN COLORADO ALONG A SURFACE CONFLUENT LINE THAT
REMAINS IN PLACE DURING THE LATER PART OF THE FORECAST PERIOD.
HIGH TEMPERATURES THROUGH THE PERIOD ARE EXPECTED TO BE ABOUT NORMAL
IN THE UPPER 80S TO LOWER 90S...AND LOW TEMPERATURES IN THE LOW TO
MID 60S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1132 PM MDT SAT AUG 8 2015
VFR CONDITIONS WILL CONTINUE FOR A FEW MORE HOURS BEFORE BOUNDARY
LAYER MOISTURE INCREASES TO THE POINT THAT STRATUS AND FOG
DEVELOPS AT KGLD AND KMCK. MVFR CONDITIONS CAN BE EXPECTED AT
BOTH SITES. VFR CONDITIONS RETURN BY LATE SUNDAY MORNING AND
CONTINUE THROUGH THE AFTERNOON AND EVENING. THERE IS ONLY A SLIGHT
CHANCE OF THUNDERSTORMS SUNDAY AFTERNOON AND EVENING WITH BETTER
CHANCES WELL TO THE SOUTH SO WILL LEAVE OUT OF THE TAFS FOR NOW.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...MK
AVIATION...FS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1141 PM MDT SAT AUG 8 2015
.SHORT TERM...(THIS AFTERNOON THROUGH SUNDAY)
ISSUED AT 229 PM MDT SAT AUG 8 2015
EARLY AFTERNOON WV IMAGERY AND RAP H5 ANALYSIS SHOWS 595 DM RIDGE
ACROSS SOUTHERN PLAINS WITH PLUME OF PACIFIC MOISTURE STREAMING INTO
THE CENTRAL ROCKIES AND ACROSS OUR CWA. SEVERAL WEAK
RIPPLES/SHORTWAVE TROUGHS WITHIN THE H5/H7 SW FLOW ARE UPSTREAM OF
THE REGION WITH SOME ENHANCEMENT ACROSS THE HIGHER TERRAIN IN THE
CENTRAL AND SOUTHERN ROCKIES. AT THE SURFACE LOW PRESSURE EXTENDS
ACROSS EASTERN COLORADO AND SOUTHWEST KANSAS. STATIONARY/WARM
FRONT IS CURRENTLY JUST OVER THE SOUTHEAST PORTIONS OF OUR CWA.
THIS AFTERNOON-TONIGHT...BAROCLINIC ZONE EXTENDING ACROSS SE CWA AND
ACROSS EASTERN COLORADO WILL ACT AS FOCUS FOR INITIATION NEAR OUR CWA
AS HEIGHT FALLS AND INCREASING ISENTROPIC ASCENT MOVES SOUTH OF
INTERSTATE 70. STRONGEST PRECIP SIGNAL IS ALONG STATIONARY FRONT IN
THE SOUTH...ESPECIALLY BY ARW/HRRR. RAP ANALYSIS SHOWS CAPE VALUES
ALREADY AROUND 4000 J/KG IN THE SOUTHEAST...WITH EFFECTIVE BULK
SHEER VALUES IN EXCESS OF 40KT. WHILE THERE IS SOME LOW LEVEL
VEERING...OVERALL SEVERE INDICES FAVOR DAMAGING WINDS AND LARGE
HAIL WITH ON A SMALL THREAT FOR TORNADOS WITHIN PROXIMITY TO MAIN
TROUGH AXIS. VERY MOIST AIR MASS...THE POSSIBILITY FOR BACKBUILDING
ALONG FRONTAL ZONE...AND STORM MOTIONS GENERALLY LESS THAN 20KT WILL
TEND TO SUPPORT POTENTIAL FOR LOCALIZED FLASH FLOODING. HI RES
GUIDANCE IS INDICATING POTENTIAL FOR THUNDERSTORMS TO FORM INTO ONE
OR SEVERAL SMALL MCS CLUSTERS ACROSS THE SOUTHERN PART OF THE
FORECAST AREA. EARLIER GUIDANCE WAS SHOWING THIS SPREADING AS FAR
NORTH AS THE I-70 CORRIDOR.
WITH LINGERING WAA ACROSS THE SE CWA...ALONG WITH SEVERAL MORE
WEAK SHORTWAVES PASSING THROUGH THE REGION...SE PORTIONS OF THE
FORECAST AREA COULD CONTINUE TO SEE SHOWER/THUNDERSTORM ACTIVITY
LINGER THROUGH SUNDAY MORNING. TREND WILL BE FOR DECREASING
INSTABILITY...SO SEVERE THREAT SHOULD BE LIMITED TO JUST THE
EVENING HOURS. VERY MOIST AIR MASS AND LIGHT WINDS WILL ALSO TEND
TO SUPPORT POTENTIAL FOR FOG/STRATUS TO REDEVELOP BY SUNRISE.
SUNDAY...WITH WEAK FORCING AND LINGERING FRONT IN OUR SE...THERE
WILL BE THE POTENTIAL FOR SHOWERS/THUNDERSTORMS THROUGH MIDDAY. NAM
SHOWS INCREASING FORCING BY LATE MORNING EARLY AFTERNOON AS A
STRONGER TROUGH DIGS INTO THE NORTHERN PLAINS. OTHER GUIDANCE IS NOT
QUITE AS FAR SOUTH...PRIMARILY FAVORS THE SOUTHER PARTS OF OUR CWA
FOR BEST THUNDERSTORM CHANCES. THERE SHOULD BE ENOUGH
INSTABILITY/SHEER IN THE AFTERNOON TO SUPPORT AT LEAST A FEW MORE
ORGANIZED THUNDERSTORMS. LOW CONFIDENCE IN HI TEMP FORECAST AS (LIKE
TODAY) TEMPS WILL BE HIGHLY DEPENDENT ON STRATUS CLEARING AND TIMING
OF THUNDERSTORM ACTIVITY. THE AIR MASS ADVERTISED OVER THE CWA WITH
AVERAGE MIXING WOULD SUPPORT SEASONAL HIGHS IN THE UPPER 80S/LOWER
90S.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 306 PM MDT SAT AUG 8 2015
FORECAST PROBLEM WILL BE CONTINUED THUNDERSTORM CHANCES. SATELLITE
IS SHOWING AN AMPLIFIED AND MOSTLY PROGRESSIVE FLOW FROM THE PACIFIC
INTO NORTH AMERICA. THIS FLOW BECOMES MORE OF A SPLIT WITH THE
TROUGHS OVER THE WESTERN AND EASTERN PORTIONS OF THE COUNTRY. OLD
CUTOFF LOW IS NOW BEING EJECTED INTO THE NORTH CENTRAL PORTION OF
THE COUNTRY. MONSOONAL MOISTURE CONTINUES TO PULLED UP INTO THE
REGION WITH EMBEDDED SHORTWAVE TROUGHS WITHIN THIS FLOW. AIR MASS
REMAINS MOIST THROUGH A SIGNIFICANT DEPTH.
AT JET LEVEL...THE GFS FOLLOWED BY THE NAM/CANADIAN WERE INITIALLY
DOING THE BEST HERE. AT MID LEVELS...MODELS WERE CLOSE WITH THE
GFS/CANADIAN/UKMET DOING SLIGHTLY BETTER. THE SREF AND NAM WERE
DOING THE BEST ON THE SURFACE WIND AND PRESSURE FIELD. MODELS WERE
HAVING A LITTLE TROUBLE ON THE LOW LEVEL THERMAL FIELD...THEY TENDED
TO BE TOO COOL. OVERALL WOULD HAVE TO GIVE A SLIGHT EDGE TO THE NAM
AND SREF.
SUNDAY NIGHT...LOOKS LIKE SOME WEAK BOUNDARY SAGS SOUTH ACROSS THE
AREA. MODELS ARE A LITTLE FASTER IN TAKING THE INITIAL SHORTWAVE
THROUGH ALTHOUGH THERE IS NOT VERY GOOD AGREEMENT IN THAT. MODELS
WANT TO BRING ANOTHER SHORTWAVE IN NORTHWEST FLOW DURING THE
OVERNIGHT HOURS WITH ALSO NOT A LOT OF AGREEMENT. RIGHT REAR
QUADRANT AFFECTS THE FAR NORTHERN PORTION OF THE AREA. WILL KEEP THE
SLIGHT TO LOW CHANCE POPS WITH A GRADUAL DECREASE THROUGH THE NIGHT.
LOOKS LIKE THERE WILL BE MAINLY STRATUS WITH NOT AS GOOD OF A CHANCE
OF FOG.
MONDAY/MONDAY NIGHT...RIDGE BEGINS TO BUILD INTO THE AREA WITH THE
UPPER JET BEING PUSHED FURTHER NORTH AWAY FROM THE AREA. AREA IS IN
POST FRONTAL UPSLOPE REGIME. RIDGING ALOFT LOOKS A LITTLE STRONGER
AND FURTHER WEST DURING THE DAY THAN WAS SHOWN YESTERDAY SO WILL
PUSH THE POPS FURTHER WEST. WILL HAVE SOME CLOUD COVER TO START THE
DAY WITH A COOLER AIR MASS AND UPSLOPE WINDS PRESENT THROUGH THE DAY
SO WILL DEFINITELY BE COOLER.
700 MB RIDGE MOVES A LITTLE TO THE EAST DURING THE NIGHT WITH
INCREASING LIFT COMING IN FROM THE SOUTHWEST. SO POPS SHOULD STAY
CONFINED TO THE SOUTHWEST HALF OF THE AREA WITH A GRADUAL INCREASE
THROUGH WITH STORMS NOT MOVING VERY FAST. THAT COMBINED WITH HIGH
PWS WILL SET THE STAGE MODERATE TO LOCALLY HEAVY RAINFALL.
TUESDAY...ABOVE MENTIONED SHORTWAVE RIDGE AND TROUGH CONTINUE TO
MOVE SLOWLY EAST THROUGH THE DAY. MOIST AIR MASS REMAIN IN PLACE
WITH INCREASING LIFT. IT IS POSSIBLE THAT THERE COULD BE SOME
PRECIPITATION AT THE BEGINNING AND THEN IT SHOULD GRADUALLY
INCREASE IN COVERAGE AND INTENSITY. SO HAVE THE HIGHER POPS IN THE
AFTERNOON.
EASTERLY WINDS...CLOUD COVER AND DEVELOPING PRECIPITATION SHOULD
KEEP TEMPERATURES SHOULD KEEP TEMPERATURES FROM WARMING VERY MUCH.
TUESDAY NIGHT THROUGH SATURDAY...DETERMINISTIC AND ENSEMBLE OUTPUT
IN BETTER AGREEMENT IN REGARDS TO THE EVOLUTION OF THE UPPER
PATTERN. ESSENTIALLY MODELS BUILD THE RIDGE...NOW CENTERED TO OUR
SOUTH...FURTHER TO THE WEST AND NORTH. THE DIFFERENCES INCREASE A
LITTLE TOWARD THE END OF THE PERIOD BUT NOT AS BAD AS YESTERDAY. THE
CENTER OF THE RIDGE WILL BE NEAR THE FOUR CORNERS REGION LEAVING A
WEAKER NORTHERLY FLOW OVER THE AREA.
IN THIS PATTERN WOULD ANTICIPATE THE SUBTROPICAL MOISTURE TO BE ABLE
TO ROTATE AROUND THE RIDGE WITH WEAK/SUBTLE SHORTWAVES ROTATING
AROUND IT. WPC PROGS SHOW A PERSISTENT FRONTAL BOUNDARY ALONG OR
OVER THE WESTERN PORTION OF THE AREA UNTIL THE LAST DAY WHEN A DRY
LINE/SURFACE TROUGH SETS UP IN THE SAME PLACE. WITH VERY SUBTLE
FEATURES...I CANNOT RULE OUT CHANCES FOR THUNDERSTORMS ALMOST EVERY
PERIOD.
SO ANY SLIGHT CHANCE TO LOW CHANCE POPS TO DRY CONDITIONS DO NOT
SEEM UNREASONABLE DEPENDING ON HOW THE DETAILS WORK OUT. SO ONCE
AGAIN DID NOT MAKE ANY CHANGES TO WHAT THE CRH_INIT GAVE ME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1132 PM MDT SAT AUG 8 2015
VFR CONDITIONS WILL CONTINUE FOR A FEW MORE HOURS BEFORE BOUNDARY
LAYER MOISTURE INCREASES TO THE POINT THAT STRATUS AND FOG
DEVELOPS AT KGLD AND KMCK. MVFR CONDTIONS CAN BE EXPECTED AT
BOTH SITES. VFR CONDITIONS RETURN BY LATE SUNDAY MORNING AND
CONTINUE THROUGH THE AFTERNOON AND EVENING. THERE IS ONLY A SLIGHT
CHANCE OF THUNDERSTORMS SUNDAY AFTERNOON AND EVENING WITH BETTER
CHANCES WELL TO THE SOUTH SO WILL LEAVE OUT OF THE TAFS FOR NOW.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...BULLER
AVIATION...FS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
532 AM EDT SUN AUG 9 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 532 AM EDT SUN AUG 9 2015
WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A VIGOROUS SHORTWAVE
MOVING ACROSS NRN ONTARIO. SEVERAL OTHER SHORTWAVES ACCOMPANIED BY
SHRA/TSTMS ARE NOTED MOVING ACROSS THE NRN AND CNTRL PLAINS. TAIL
END OF FORCING ASSOCIATED WITH NRN ONTARIO SHORTWAVE OVERTOP 850MB
THETA-E RIDGE HAS BEEN SUPPORTING ISOLD/SCT SHRA/TSTM DEVELOPMENT
OVE WRN UPPER MI SINCE SHORTLY AFTER MIDNIGHT. DESPITE LACK OF
INSTABILITY (MUCAPE NO HIGHER THAN 400J/KG)...A FEW OF THE STORMS
WERE FAIRLY STRONG AND LIKELY PRODUCED AT LEAST PEA-SIZE HAIL. RADAR
ESTIMATED INSTANTANEOUS PCPN RATES HAVE BEEN PRETTY IMPRESSIVE AS
WELL...THOUGH RAINFALL CORES HAVE BEEN VERY SMALL.
00Z MODEL RUNS INCLUDING HOURLY RAP/HRRR RUNS SINCE 00Z INDICATE
ONGOING ISOLD/SCT SHRA/TSTMS WILL PROBABLY PERSIST AND REACH CNTRL
UPPER MI BEFORE DIMINISHING AND PERHAPS ENDING FOR THE MOST PART.
ATTENTION THEN TURNS TO THE AFTN. BUILDING INSTABILITY AND
APPROACHING COLD FRONT WILL SPARK A NEW ROUND OF SHRA/TSTMS WITH
MODELS POINTING TOWARD BARAGA/MARQUETTE/IRON COUNTIES AS THE LIKELY
FOCAL AREA FOR GREATEST COVERAGE OF DEVELOPMENT. NAM CONTINUES TO BE
VERY AGGRESSIVE BUILDING MLCAPES TO OVER 1500J/KG OVER WRN UPPER MI
AND AS HIGH AS NEARLY 2500J/KG. GFS TOPS OUT AROUND 1000J/KG WHILE
RECENT RAP RUNS ONLY TOP OUT NEAR 500J/KG. 21Z SREF INDICATES ABOUT
A 30PCT CHANCE OF MLCAPES INCREASING TO OVER 1000J/KG...SO THE NAM
DEFINITELY LOOKS LIKE A HIGH OUTLIER. A REASONABLE EXPECTATION IS
PROBABLY MLCAPES OF 500-1000J/KG. WITH DEEP LAYER SHEAR TOPPING OUT
AROUND 25KT...SVR RISK APPEARS MINIMAL...UNLESS INSTABILITY BUILDS
HIGHER THAN CURRENTLY EXPECTED. SOME SMALL HAIL WILL BE POSSIBLE
WITH THE STRONGEST STORMS. ALSO...EXPECT BRIEF LOCALLY HVY RAINFALL.
SHRA/TSTMS WILL SHIFT E TONIGHT AND DIMINISH. LIGHT WINDS IN THE
VCNTY OF THE PASSING FRONT ALONG WITH EXPECTED RAINFALL SHOULD
RESULT IN FOG DEVELOPING...ESPECIALLY ACROSS SCNTRL/SE UPPER MI.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 444 AM EDT SUN AUG 9 2015
AT 12Z MONDAY THE APEX OF THE 500MB TROUGH /EXTENDING FROM THE LOW
OVER JAMES BAY/ WILL BE OVERHEAD...WITH SHOWERS EXITING THE E CWA.
A SECONDARY SHORTWAVE SWINGING AROUND THE MAIN TROUGH WILL PUSH IN
FROM THE NW MONDAY NIGHT. WITH LIMITED MOISTURE...DO NOT EXPECT MUCH
IN THE WAY OF PRECIP. MODELS DO SHOW SOME INCREASE IN LOW LEVEL
MOISTURE...BELOW 800MB...WITH THE BEST MOISTURE ASSISTED BY N-NNW
FLOW OVER THE E THIRD OF UPPER MI.
EXPECT A MAINLY N WIND TO REMAIN JUST ABOVE THE SFC THROUGH THE
FIRST HALF OF THE WORK WEEK. 850MB TEMPS OF 8-11C WILL HELP KEEP
AFTERNOON SFC TEMPS IN THE 70S MONDAY-WEDNESDAY. AT THIS POINT
TUESDAY LOOKS TO BE THE COOLEST DAY...WITH A FEW READINGS IN THE
UPPER 60S ALONG LAKE SUPERIOR AS A LARGE AREA OF HIGH PRESSURE AT
THE SFC SETTLES OVERHEAD.
THE BROAD 500MB TROUGH WILL EXIT E WEDNESDAY...WITH RIDGING BUILDING
ACROSS THE UPPER GREAT LAKES REGION. THE DRY WEATHER WILL BE SHORT
LIVED AS A SLIGHT CHANCE OF RETURNS OVER LAKE SUPERIOR WEDNESDAY
NIGHT...AS THE 500MB RIDGE BECOMES SUPPRESSED SETTING THE STAGE FOR
NW FLOW ALOFT AND ADDITIONAL DISTURBANCES/UNSETTLED WX THROUGH
THURSDAY NIGHT. THE SFC LOW WELL TO OUR N IN CANADA WILL DRAG A COLD
FRONT NW-SE FROM AROUND 21Z THURSDAY TO 12Z FRIDAY.
DRY WEATHER SHOULD RETURN AGAIN AS THE COLD FRONT SLIPS ACROSS LOWER
MI FRIDAY AND HIGH PRESSURE BUILDS IN FOR THE START OF THE WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 126 AM EDT SUN AUG 9 2015
MVFR VSBYS ARE POSSIBLE THRU THE EARLY MORNING HRS AT KSAW...
ALTHOUGH THE LIKELIHOOD OF IFR OR LOWER CONDITIONS HAVE DECREASED DUE
TO THE MID LEVEL CLOUDS ACROSS THE AREA FROM THE THUNDERSTORMS ACROSS
MN. THERE IS A POSSIBILITY OF A STRAY SHOWER OR STORM AT KIWD AND
KCMX LATE IN THE NIGHT...BUT DRY AIR ACROSS THE AREA WILL LIKELY
KEEP ANY STORMS WEST OF THE AREA UNTIL LATE MORNING/AFTN AS THE COLD
FRONT PASSES THROUGH. THE BEST CHANCE OF SHOWERS AND STORMS WOULD BE
AT KSAW THIS AFTERNOON...BUT AT THIS TIME WILL KEEP OUT OF THE
TERMINAL FORECAST OTHER THAN VCSH. BEHIND THE FRONT...WINDS WILL TURN
WESTERLY AND THE SHOWER ACTIVITY WILL END. SOME INDICATIONS OF IFR
VSBYS TONIGHT INTO MONDAY MORNING...BUT THIS WILL LIKELY DEPEND OF
HOW MUCH RAIN WE GET TODAY.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 532 AM EDT SUN AUG 9 2015
COLD FRONT MOVING ACROSS LAKE SUPERIOR THIS AFTN AND TONIGHT WILL
LEAD TO A WIND SHIFT FROM SOUTHERLY TO NORTHWESTERLY. WITH GENERALLY
A WEAK PRES GRADIENT...WINDS SHOULD REMAIN UNDER 20KT TODAY THRU
MON. MON NIGHT/TUE...GRADIENT TIGHTENS A BIT AHEAD OF APPROACHING
SFC HIGH PRES...SO WINDS OVER THE E HALF OF LAKE SUPERIOR WILL
PROBABLY BEGIN TO GUST MORE FREQUENTLY TO AROUND 20KT. ARRIVAL OF
SFC HIGH PRES RIDGE WILL RESULT IN WINDS UNDER 15KT TUE NIGHT/WED.
WINDS WILL THEN INCREASE SOME INTO THU AHEAD OF THE NEXT APPROACHING
COLD FRONT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KF
AVIATION...MRD
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
445 AM EDT SUN AUG 9 2015
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 250 PM EDT SAT AUG 8 2015
THE UPPER GREAT LAKES REGION WILL BE BETWEEN UPPER LEVEL FEATURES
OVER THE NEXT 24 HOURS...LEADING TO SOME UNCERTAINTY IN THE COVERAGE
AND AMOUNT OF PRECIPITATION THAT WILL OCCUR AHEAD OF THE COLD FRONT
TONIGHT. THE MAIN SHORTWAVE IS CURRENTLY LOCATED JUST TO THE EAST OF
LAKE WINNIPEG AND HAS A 1002MB SURFACE LOW LOCATED WITH IT. A COLD
FRONT STRETCHES SOUTH-SOUTHEAST FROM THIS LOW AND INTO NORTHERN
MINNESOTA (CURRENTLY FROM THE LAKE OF THE WOODS TO JUST TO THE EAST
OF FARGO). HAVE SEEN SOME SHOWERS AND THUNDERSTORMS DEVELOP AROUND
PARK RAPIDS MINNESOTA A COUPLE HOURS AGO AND THEY HAVE BEEN MAKING
THERE WAY TO THE EAST TOWARDS LEECH LAKE AHEAD OF THAT FRONT AND IN
THE RIBBON OF DEEPER MOISTURE FROM 925-700MB AHEAD OF THE ASSOCIATED
TROUGH. OVER THE U.P....THE ABUNDANT DRY AIR SEEN ABOVE 700MB ON THE
12Z KGRB SOUNDING AND ON RAP ANALYSIS DATA...ASSOCIATED WITH THE
SURFACE RIDGE FROM A HIGH NEAR JAMES BAY...HAS BEEN LIMITING THE
EASTWARD EXTENT OF THE OF SHOWERS AS THEY MOVE INTO WESTERN LAKE
SUPERIOR. BUT WITH THE MOISTURE BELOW 700MB...HAVE SEEN DIURNAL CU
FILL IN THE GAPS FROM EARLIER TODAY BETWEEN THE SOUTHEASTERLY FLOW
UPSLOPE FOG AND LOW CLOUDS. TEMPERATURES HAVE WARMED INTO THE 70S
ACROSS THE AREA...WITH THE WARMEST VALUES OVER THE EAST WITH MORE
SUNSHINE. FINALLY FARTHER TO THE SOUTH...A SHORTWAVE ROUNDING THE
UPPER RIDGE OVER TEXAS/OKLAHOMA LED TO AN MCS MOVING THROUGH
NORTHEAST KANSAS AND SOUTHWEST MISSOURI EARLY THIS MORNING AND IT
HAS SINCE DISSIPATED. BUT WITH ANOTHER WAVE ROUNDING THE RIDGE
THROUGH NEBRASKA...WOULD EXPECT REDEVELOPMENT TO THE EAST OF THAT
AREA OVER THE NEXT COUPLE OF HOURS.
WITH THE SOUTHERN SHORTWAVE STAYING WELL TO THE SOUTH OF THE
AREA...THE MAIN FOCUS WILL BE WITH THE UPPER LOW NEAR LAKE WINNIPEG
SLOWLY WEAKENING AS IT MOVES EAST TOWARDS JAMES BAY. THIS WILL LEAD
TO THE SURFACE LOW FOLLOWING SUIT AND SLOWLY DRAGGING THE COLD FRONT
EAST ACROSS THE CWA. HAVE ALREADY SEEN SHOWERS/THUNDERSTORMS DEVELOP
IN NORTHERN MINNESOTA AHEAD OF THE FRONT AND WITH THE STORM MOTION
VALUES INDICATING EASTWARD MOVEMENT UP TO 30KTS...WOULD EXPECT THE
SHOWERS TO SPREAD EAST INTO WESTERN LAKE SUPERIOR AND EVENTUALLY THE
WESTERN U.P. TONIGHT. LIKE LAST NIGHT AND TODAY...THEY WILL BE
BATTLING THE EXISTING DRY MID LEVEL AIR AS THEY MOVE OUT AHEAD OF
THE SLOW MOVING SURFACE-850MB TROUGH...SO WOULD EXPECT SOME
DIMINISHMENT AS THEY HEAD TO THE EAST AND INTO THE CWA TONIGHT.
WOULD EXPECT SOME MARGINALLY SEVERE STORMS TO MOVE INTO WESTERN LAKE
SUPERIOR BEFORE THE DRY AIR AND LOSS OF DIURNAL HEATING STARTS TO
TAKE ITS TOLL. OVER THE CENTRAL AND EASTERN U.P....AM EXPECTED SOME
PATCHY GROUND FOG TO DEVELOP TONIGHT. THICKNESS WILL DEPEND ON THE
AMOUNT OF DECOUPLING THAT OCCURS TONIGHT. HAVE SHOWN THE THICKEST
FOG (AREAS COVERAGE) OVER THE CENTRAL U.P. FOR SOUTHERN
MARQUETTE...DICKINSON...DELTA...AND NORTHERN MENOMINEE COUNTIES.
WITH THE COLD FRONT STILL OFF TO THE WEST OF THE U.P. ON SUNDAY
MORNING...EXPECT THERE TO BE TIME FOR DIURNAL HEATING TO INCREASE
THE POTENTIAL FOR SHOWERS/THUNDERSTORMS OVER THE WEST/CENTRAL U.P.
DURING THE AFTERNOON. MODELS HAVE A VARIETY OF IDEAS ON ML CAPE
VALUES...RANGING FROM 250-2000 J/KG TOMORROW AFTERNOON JUST AHEAD OF
THE FRONT. LOOKING AT MODIFIED SOUNDINGS AND MEAN ML CAPE VALUES
FROM THE NCAR ENSEMBLES AND SREF...FEEL THAT VALUES AROUND 500-750
J/KG ARE A FAIRLY REASONABLE EXPECTATION AT THIS POINT. WITH 0-6KM
BULK SHEAR VALUES GENERALLY AROUND 25-30KTS...THERE IS THE POTENTIAL
FOR AN ISOLATED STRONGER STORM TOMORROW AFTERNOON. THAT MATCHES THE
IDEA FROM UPDRAFT VELOCITY/HELICITY FROM THE CAM/S AND CAM
ENSEMBLES. WITH WET BULB ZERO VALUES NEARING 10KFT AND FREEZING
LEVEL ABOVE 12KFT...THINK THAT WILL COMBINE WITH THE MARGINAL SHEAR
TO KEEP THE HAIL THREAT BORDERLINE. LIKED THE PREVIOUS SHIFTS
HANDLING OF THE DEVELOPMENT OF THE SHOWERS/THUNDERSTORMS ACROSS THE
CENTRAL U.P. (RAMPING UP TO LOCALIZED LIKELY VALUES OVER MARQUETTE
COUNTY) AND HAVE ONLY MADE MINOR ADJUSTMENTS BASED OFF LATEST MODEL
TRENDS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 444 AM EDT SUN AUG 9 2015
AT 12Z MONDAY THE APEX OF THE 500MB TROUGH /EXTENDING FROM THE LOW
OVER JAMES BAY/ WILL BE OVERHEAD...WITH SHOWERS EXITING THE E CWA.
A SECONDARY SHORTWAVE SWINGING AROUND THE MAIN TROUGH WILL PUSH IN
FROM THE NW MONDAY NIGHT. WITH LIMITED MOISTURE...DO NOT EXPECT MUCH
IN THE WAY OF PRECIP. MODELS DO SHOW SOME INCREASE IN LOW LEVEL
MOISTURE...BELOW 800MB...WITH THE BEST MOISTURE ASSISTED BY N-NNW
FLOW OVER THE E THIRD OF UPPER MI.
EXPECT A MAINLY N WIND TO REMAIN JUST ABOVE THE SFC THROUGH THE
FIRST HALF OF THE WORK WEEK. 850MB TEMPS OF 8-11C WILL HELP KEEP
AFTERNOON SFC TEMPS IN THE 70S MONDAY-WEDNESDAY. AT THIS POINT
TUESDAY LOOKS TO BE THE COOLEST DAY...WITH A FEW READINGS IN THE
UPPER 60S ALONG LAKE SUPERIOR AS A LARGE AREA OF HIGH PRESSURE AT
THE SFC SETTLES OVERHEAD.
THE BROAD 500MB TROUGH WILL EXIT E WEDNESDAY...WITH RIDGING BUILDING
ACROSS THE UPPER GREAT LAKES REGION. THE DRY WEATHER WILL BE SHORT
LIVED AS A SLIGHT CHANCE OF RETURNS OVER LAKE SUPERIOR WEDNESDAY
NIGHT...AS THE 500MB RIDGE BECOMES SUPPRESSED SETTING THE STAGE FOR
NW FLOW ALOFT AND ADDITIONAL DISTURBANCES/UNSETTLED WX THROUGH
THURSDAY NIGHT. THE SFC LOW WELL TO OUR N IN CANADA WILL DRAG A COLD
FRONT NW-SE FROM AROUND 21Z THURSDAY TO 12Z FRIDAY.
DRY WEATHER SHOULD RETURN AGAIN AS THE COLD FRONT SLIPS ACROSS LOWER
MI FRIDAY AND HIGH PRESSURE BUILDS IN FOR THE START OF THE WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 126 AM EDT SUN AUG 9 2015
MVFR VSBYS ARE POSSIBLE THRU THE EARLY MORNING HRS AT KSAW...
ALTHOUGH THE LIKELIHOOD OF IFR OR LOWER CONDITIONS HAVE DECREASED DUE
TO THE MID LEVEL CLOUDS ACROSS THE AREA FROM THE THUNDERSTORMS ACROSS
MN. THERE IS A POSSIBILITY OF A STRAY SHOWER OR STORM AT KIWD AND
KCMX LATE IN THE NIGHT...BUT DRY AIR ACROSS THE AREA WILL LIKELY
KEEP ANY STORMS WEST OF THE AREA UNTIL LATE MORNING/AFTN AS THE COLD
FRONT PASSES THROUGH. THE BEST CHANCE OF SHOWERS AND STORMS WOULD BE
AT KSAW THIS AFTERNOON...BUT AT THIS TIME WILL KEEP OUT OF THE
TERMINAL FORECAST OTHER THAN VCSH. BEHIND THE FRONT...WINDS WILL TURN
WESTERLY AND THE SHOWER ACTIVITY WILL END. SOME INDICATIONS OF IFR
VSBYS TONIGHT INTO MONDAY MORNING...BUT THIS WILL LIKELY DEPEND OF
HOW MUCH RAIN WE GET TODAY.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 250 PM EDT SAT AUG 8 2015
A LOW MOVING FROM JUST EAST OF LAKE WINNIPEG TO JAMES BAY THIS
WEEKEND WILL SWEEP A SURFACE TROUGH ACROSS LAKE SUPERIOR ON
SUNDAY...LEADING TO A SHIFT IN THE WINDS FROM A LIGHT SOUTH TO
SOUTHEASTERLY DIRECTION TO THE NORTHWEST BY MONDAY. WITH A
GENERALLY LIGHT PRESSURE GRADIENT IN PLACE...EXPECT WINDS TO STAY
BELOW 20KTS THROUGH THE PERIOD...ESPECIALLY AFTER TUESDAY WHEN HIGH
PRESSURE WILL SETTLE OVER THE GREAT LAKES REGION FOR THE MIDDLE OF
NEXT WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...KF
AVIATION...MRD
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
129 AM EDT SUN AUG 9 2015
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 250 PM EDT SAT AUG 8 2015
THE UPPER GREAT LAKES REGION WILL BE BETWEEN UPPER LEVEL FEATURES
OVER THE NEXT 24 HOURS...LEADING TO SOME UNCERTAINTY IN THE COVERAGE
AND AMOUNT OF PRECIPITATION THAT WILL OCCUR AHEAD OF THE COLD FRONT
TONIGHT. THE MAIN SHORTWAVE IS CURRENTLY LOCATED JUST TO THE EAST OF
LAKE WINNIPEG AND HAS A 1002MB SURFACE LOW LOCATED WITH IT. A COLD
FRONT STRETCHES SOUTH-SOUTHEAST FROM THIS LOW AND INTO NORTHERN
MINNESOTA (CURRENTLY FROM THE LAKE OF THE WOODS TO JUST TO THE EAST
OF FARGO). HAVE SEEN SOME SHOWERS AND THUNDERSTORMS DEVELOP AROUND
PARK RAPIDS MINNESOTA A COUPLE HOURS AGO AND THEY HAVE BEEN MAKING
THERE WAY TO THE EAST TOWARDS LEECH LAKE AHEAD OF THAT FRONT AND IN
THE RIBBON OF DEEPER MOISTURE FROM 925-700MB AHEAD OF THE ASSOCIATED
TROUGH. OVER THE U.P....THE ABUNDANT DRY AIR SEEN ABOVE 700MB ON THE
12Z KGRB SOUNDING AND ON RAP ANALYSIS DATA...ASSOCIATED WITH THE
SURFACE RIDGE FROM A HIGH NEAR JAMES BAY...HAS BEEN LIMITING THE
EASTWARD EXTENT OF THE OF SHOWERS AS THEY MOVE INTO WESTERN LAKE
SUPERIOR. BUT WITH THE MOISTURE BELOW 700MB...HAVE SEEN DIURNAL CU
FILL IN THE GAPS FROM EARLIER TODAY BETWEEN THE SOUTHEASTERLY FLOW
UPSLOPE FOG AND LOW CLOUDS. TEMPERATURES HAVE WARMED INTO THE 70S
ACROSS THE AREA...WITH THE WARMEST VALUES OVER THE EAST WITH MORE
SUNSHINE. FINALLY FARTHER TO THE SOUTH...A SHORTWAVE ROUNDING THE
UPPER RIDGE OVER TEXAS/OKLAHOMA LED TO AN MCS MOVING THROUGH
NORTHEAST KANSAS AND SOUTHWEST MISSOURI EARLY THIS MORNING AND IT
HAS SINCE DISSIPATED. BUT WITH ANOTHER WAVE ROUNDING THE RIDGE
THROUGH NEBRASKA...WOULD EXPECT REDEVELOPMENT TO THE EAST OF THAT
AREA OVER THE NEXT COUPLE OF HOURS.
WITH THE SOUTHERN SHORTWAVE STAYING WELL TO THE SOUTH OF THE
AREA...THE MAIN FOCUS WILL BE WITH THE UPPER LOW NEAR LAKE WINNIPEG
SLOWLY WEAKENING AS IT MOVES EAST TOWARDS JAMES BAY. THIS WILL LEAD
TO THE SURFACE LOW FOLLOWING SUIT AND SLOWLY DRAGGING THE COLD FRONT
EAST ACROSS THE CWA. HAVE ALREADY SEEN SHOWERS/THUNDERSTORMS DEVELOP
IN NORTHERN MINNESOTA AHEAD OF THE FRONT AND WITH THE STORM MOTION
VALUES INDICATING EASTWARD MOVEMENT UP TO 30KTS...WOULD EXPECT THE
SHOWERS TO SPREAD EAST INTO WESTERN LAKE SUPERIOR AND EVENTUALLY THE
WESTERN U.P. TONIGHT. LIKE LAST NIGHT AND TODAY...THEY WILL BE
BATTLING THE EXISTING DRY MID LEVEL AIR AS THEY MOVE OUT AHEAD OF
THE SLOW MOVING SURFACE-850MB TROUGH...SO WOULD EXPECT SOME
DIMINISHMENT AS THEY HEAD TO THE EAST AND INTO THE CWA TONIGHT.
WOULD EXPECT SOME MARGINALLY SEVERE STORMS TO MOVE INTO WESTERN LAKE
SUPERIOR BEFORE THE DRY AIR AND LOSS OF DIURNAL HEATING STARTS TO
TAKE ITS TOLL. OVER THE CENTRAL AND EASTERN U.P....AM EXPECTED SOME
PATCHY GROUND FOG TO DEVELOP TONIGHT. THICKNESS WILL DEPEND ON THE
AMOUNT OF DECOUPLING THAT OCCURS TONIGHT. HAVE SHOWN THE THICKEST
FOG (AREAS COVERAGE) OVER THE CENTRAL U.P. FOR SOUTHERN
MARQUETTE...DICKINSON...DELTA...AND NORTHERN MENOMINEE COUNTIES.
WITH THE COLD FRONT STILL OFF TO THE WEST OF THE U.P. ON SUNDAY
MORNING...EXPECT THERE TO BE TIME FOR DIURNAL HEATING TO INCREASE
THE POTENTIAL FOR SHOWERS/THUNDERSTORMS OVER THE WEST/CENTRAL U.P.
DURING THE AFTERNOON. MODELS HAVE A VARIETY OF IDEAS ON ML CAPE
VALUES...RANGING FROM 250-2000 J/KG TOMORROW AFTERNOON JUST AHEAD OF
THE FRONT. LOOKING AT MODIFIED SOUNDINGS AND MEAN ML CAPE VALUES
FROM THE NCAR ENSEMBLES AND SREF...FEEL THAT VALUES AROUND 500-750
J/KG ARE A FAIRLY REASONABLE EXPECTATION AT THIS POINT. WITH 0-6KM
BULK SHEAR VALUES GENERALLY AROUND 25-30KTS...THERE IS THE POTENTIAL
FOR AN ISOLATED STRONGER STORM TOMORROW AFTERNOON. THAT MATCHES THE
IDEA FROM UPDRAFT VELOCITY/HELICITY FROM THE CAM/S AND CAM
ENSEMBLES. WITH WET BULB ZERO VALUES NEARING 10KFT AND FREEZING
LEVEL ABOVE 12KFT...THINK THAT WILL COMBINE WITH THE MARGINAL SHEAR
TO KEEP THE HAIL THREAT BORDERLINE. LIKED THE PREVIOUS SHIFTS
HANDLING OF THE DEVELOPMENT OF THE SHOWERS/THUNDERSTORMS ACROSS THE
CENTRAL U.P. (RAMPING UP TO LOCALIZED LIKELY VALUES OVER MARQUETTE
COUNTY) AND HAVE ONLY MADE MINOR ADJUSTMENTS BASED OFF LATEST MODEL
TRENDS.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 315 PM EDT SAT AUG 8 2015
AFTER ANY LINGERING SHOWERS END ON MON FOLLOWING A SUN NGT COLD
FROPA...THE NW FLOW BTWN A BLDG UPR RDG IN THE PLAINS AND AN
AMPLIFYING TROF OVER ERN NAMERICA WL BE THE DOMINATING INFLUENCE ON
UPR MI WX EARLY IN THE WEEK. THE RESULT WL BE A RETURN OF DRY AND
COOLER WX FOR THE MOST PART MON INTO WED. THE NEXT CHC OF SHOWERS/TS
WL ARRIVE WITH WARMER AIR WED NGT THRU THU NGT AHEAD OF A SHRTWV
MOVING OVER THE TOP OF THE RDG/THRU NW ONTARIO AND ITS ATTENDANT
COLD FNT. HI PRES TRAILING THIS COLD FNT SHOULD BRING A SEASONABLE
AIRMASS/DRIER WX LATE IN THE WEEK.
SUN NGT...SHRTWV DRIFTING ESEWD THRU FAR NORTHERN ONTARIO WL REACH
NEAR JAMES BAY BY 12Z MON AND DRAG ATTENDANT COLD FNT SLOWLY THRU
THE UPR LKS. SINCE THE SHARPER DYNAMIC FORCING ASSOCIATED WITH THE
ONTARIO SHRTWV WL BE REMAIN TO THE N AND H85 THETA E ADVECTION/
DEEPER MSTR INFLOW WL BE WEAK AT BEST...EXPECT NO MORE THAN A CHC OF
SHOWERS/TS. THE BEST CHC FOR THIS PCPN WL BE IN THE EVNG OVER
CENTRAL UPR MI...WHERE AXIS OF SOMEWHAT HIER H85 THETA E WL BE
PRESENT AT TIME WHEN DAYTIME HEATING WL STILL BE A FACTOR. THE
MAJORITY OF THE MODELS SHOW A TRAILING SHRTWV/AREA OF HIER MID LVL
MSTR/SOME DPVA AND H7-3 QVECTOR CNVGC APRCHG FM CENTRAL MN FOLLOWING
THE COLD FROPA. HOWEVER...NOCTURNAL COOLING AND LLVL DRYING/
NEGATIVE H85 THETA E ADVCTN WL LIMIT THE COVERAGE/INTENSITY OF ANY
SHOWERS THAT MIGHT ACCOMPANYING THIS HIER LVL FORCING. EXPECT THE
LOWEST MIN TEMPS OVER THE W...WHERE H85 TEMPS ARE FCST TO FALL TO
ARND 11C BY DAYBREAK.
MON...EXPECT ANY LINGERING SHOWERS OVER THE E AND SCENTRAL TO
DIMINISH WITH ARRIVAL OF DEEP DRYING/INCRSG LLVL ACYC NNW FLOW AHEAD
OF CNDN HI PRES BLDG INTO MANITOBA. LINGERING MID CLDS WL GIVE WAY
TO SOME DIURNAL CU/SC IN THE AFTN. EXPECT HI TEMPS MAINLY IN THE 70S
TO NEAR 80 OVER THE SCNTRL WITH H85 TEMPS IN THE 12-14C RANGE.
LOCATIONS NEAR LK SUP WL BE COOLEST WITH A NW FLOW OFF THE WATER.
MON NGT THRU TUE NGT...ARRIVAL OF MORE VIGOROUS DEEP LYR QVECTOR
DVGC/SUBSIDENCE UNDER CONFLUENT NW FLOW ALOFT BTWN PLAINS RDG/ERN
TROF AND H85 TEMPS FALLING AS LO AS 8 TO 10C IN THE LLVL NLY FLOW
AHEAD OF CNDN HI PRES BLDG TOWARD THE UPR LKS WL RESULT IN A PERIOD
OF COOLER AND DRIER WX FOR THE CWA. SOME OF THE MODELS HAVE BEEN
GENERATING SOME LGT PCPN MAINLY DURING DAYTIME HEATING ON TUE
ACCOMPANYING THE PASSAGE OF A SHRTWV IN THE NW FLOW. BUT ABSENCE OF
ANY MSTR INFLOW...LARGER SCALE NEGATIVE DYNAMIC FORCING/SUBSIDENCE
THAT WL MAINTAIN MID LVL CAPPING SHOWN ON THE GFS FCST SDNGS AS WELL
AS DIFFLUENT LLVL FLOW WARRANTS MAINTAINING GOING DRY FCST FOR NOW.
BUT THERE WL BE A GOOD DEAL OF DIURNAL CU ON TUE UNDER INCOMING H85
THERMAL TROF. EXPECT LO TEMPS ON TUE NGT TO FALL INTO THE 40S AT THE
COOLER INTERIOR LOCATIONS WITH MOCLR SKIES/LIGHT WINDS AS THE SFC HI
PRES MOVES OVHD.
WED...AS THE HI CENTER DRIFTS TO THE S...THE LLVL FLOW WL TURN TO
THE WSW. THE WARMING RELATED TO SOME WAA AND CONTINUED SUBSIDENCE
UNDER THE SLOWLY EXPANDING PLAINS RDG/RISING HGTS IS FCST TO BOOST
H85 TEMPS TO ARND 16C OVER THE W LATE IN THE DAY. EXPECT A WARMER
DAY THAN ON TUE...WITH HI TEMPS AT LEAST APRCHG 80 ESPECIALLY OVER
THE W AWAY FM LK MODERATION...EVEN IF SOME WAA CLDS SPILL OVER THE
CWA IN THE AFTN.
WED NGT THRU THU NGT...ALTHOUGH THERE ARE SOME DIFFERENCES IN THE
DETAILS AS EXPECTED SO FAR INTO THE FUTURE...THE LONGER RANGE
GUIDANCE INDICATES A SHRTWV RIDING OVER THE PLAINS RDG WL DROP SEWD
THRU NW ONTARIO ON THU/THU NGT AND DRAG A COLD FNT THRU THE UPR LKS
ON THU NGT. SOME OF THE MODELS GENERATE SOME LGT PCPN AS EARLY AS
WED NGT IN THE WSW FLOW/WAA BTWN THE RETREATING HI PRES TO THE S AND
FALLING MSLP OVER SCENTRAL CANADA AHEAD OF THE SHRTWV. BUT LINGERING
LLVL ACYC FLOW AND RELATIVE DRYNESS OF AIRMASS INDICATE ANY SHOWERS
WL BE WIDELY SCT AT BEST. A BETTER CHC FOR SHOWERS/TS APPEARS WL
COME LATE THU/THU EVNG WITH THE ARRIVAL OF SOME DEEP LYR QVECTOR
CNVGC ASSOCIATED WITH THE ONTARIO SHRTWV AND AHEAD OF APRCHG COLD
FNT DURING PERIOD OF DAYTIME HEATING. THE 12Z GFS IS MOST VIGOROUS
WITH THIS DISTURBANCE AND INDICATES THE POTENTIAL FOR SOME SVR
STORMS WITH MUCAPE FCST AS HI AS 2500 J/KG AND DEEP LYR SHEAR UP TO
40 KTS. THE 12Z ECMWF/CNDN MODELS SHOW A LESS IMPRESSIVE SCENARIO
WITH WEAKER MSTR RETURN. GIVEN MODEL DIFFERENCES AND UNCERTAINTY ON
THE DEGREE OF MSTR RETURN WITH SHARPEST FORCING REMAINING TO THE
NE...CONSENSUS LO CHC POPS AT THIS POINT SEEM REASONABLE. THU LOOKS
TO BE THE WARMEST DAY OF THE WEEK UNDER THERMAL RDG/H85 TEMPS UP TO
18-20C AHEAD OF INCOMING COLD FNT.
FRI/SAT...HI PRES TRAILING THE SHRTWV SHOULD BRING DRY AND SOMEWHAT
COOLER WX AT LEAST ON FRI/FRI NGT. THERE IS SOME UNCERTAINTY ON HOW
QUICKLY WAA SHOWERS/TS RETURN BTWN THE RETREATING HI AND ANOTHER
SHRTWV RIDING OVER THE PLAINS RDG LATER ON SAT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 126 AM EDT SUN AUG 9 2015
MVFR VSBYS ARE POSSIBLE THRU THE EARLY MORNING HRS AT KSAW...
ALTHOUGH THE LIKELIHOOD OF IFR OR LOWER CONDITIONS HAVE DECREASED DUE
TO THE MID LEVEL CLOUDS ACROSS THE AREA FROM THE THUNDERSTORMS ACROSS
MN. THERE IS A POSSIBILITY OF A STRAY SHOWER OR STORM AT KIWD AND
KCMX LATE IN THE NIGHT...BUT DRY AIR ACROSS THE AREA WILL LIKELY
KEEP ANY STORMS WEST OF THE AREA UNTIL LATE MORNING/AFTN AS THE COLD
FRONT PASSES THROUGH. THE BEST CHANCE OF SHOWERS AND STORMS WOULD BE
AT KSAW THIS AFTERNOON...BUT AT THIS TIME WILL KEEP OUT OF THE
TERMINAL FORECAST OTHER THAN VCSH. BEHIND THE FRONT...WINDS WILL TURN
WESTERLY AND THE SHOWER ACTIVITY WILL END. SOME INDICATIONS OF IFR
VSBYS TONIGHT INTO MONDAY MORNING...BUT THIS WILL LIKELY DEPEND OF
HOW MUCH RAIN WE GET TODAY.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 250 PM EDT SAT AUG 8 2015
A LOW MOVING FROM JUST EAST OF LAKE WINNIPEG TO JAMES BAY THIS
WEEKEND WILL SWEEP A SURFACE TROUGH ACROSS LAKE SUPERIOR ON
SUNDAY...LEADING TO A SHIFT IN THE WINDS FROM A LIGHT SOUTH TO
SOUTHEASTERLY DIRECTION TO THE NORTHWEST BY MONDAY. WITH A
GENERALLY LIGHT PRESSURE GRADIENT IN PLACE...EXPECT WINDS TO STAY
BELOW 20KTS THROUGH THE PERIOD...ESPECIALLY AFTER TUESDAY WHEN HIGH
PRESSURE WILL SETTLE OVER THE GREAT LAKES REGION FOR THE MIDDLE OF
NEXT WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...KC
AVIATION...MRD
MARINE...SRF
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
328 AM CDT SUN AUG 9 2015
.SYNOPSIS...
ISSUED AT 328 AM CDT SUN AUG 9 2015
AN AREA OF SHOWERS AND THUNDERSTORMS CONTINUES TO MOVE FROM CENTRAL
INTO EASTERN SOUTH DAKOTA ASSOCIATED NEAR A WEAK FRONTAL BOUNDARY
EXTENDING FROM SRN MINN THROUGH CENTRAL SOUTH DAKOTA INTO THE
WESTERN NEBR PNHDL. ANOTHER AREA OF THUNDERSTORMS REMAINS ANCHORED
ON THE CUSP OF A WARM FRONT FROM ECTRL NEBR INTO SWRN IA.
DEWPOINTS IN WRN NEBR RANGING IN THE MID TO UPPER 60S. PATCHY FOG
EXISTS FROM CENTRAL INTO NERN NEBR.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 328 AM CDT SUN AUG 9 2015
NEAR TERM CONCERN IS THE DEVELOPMENT OF PATCHY FOG UNTIL MID
MORNING. MODELS ARE IN FAIR AGREEMENT FOR FOG TO CONTINUE EXPANDING
WESTWARD INTO THE SERN PNHDL AND SWRN NEBR. SKIES LOOK TO BE PARTLY
SUNNY TODAY...WITH ANY STRATUS FROM EARLY MORNING FOG TO BURN OFF BY
10AM CDT. FCST HIGHS TODAY TO RANGE MAINLY FROM 86 TO 90 DEGREES
WITH A DOWNSLOPING WESTERLY WINDS HELPING TO MIX DOWN H85 TEMPS OF
23 TO 27C. SHOWERS AND THUNDERSTORMS ARE FORECAST TO DEVELOP THIS
AFTERNOON IN NCTRL NEBR SOUTHWARD ACROSS THE ERN HALF OF THE FA.
WHILE MID LEVEL LAPSE RATES ARE ONLY 6.5 TO 7C/KM...SBCAPES WILL
INCREASE TO 1500 TO 2000 J/KG EAST OF AN ANW THROUGH NORTH PLATTE
LINE. THE STRONGEST DEEP LAYER SHEAR WILL BE IN NERN FA RANGING FROM
40 TO 50 KTS SUPPORTIVE OF A FEW SEVERE STORMS. AREA FOR BEST STORM
DEVELOPMENT WILL BE FROM SCTRL SD INTO THE ERN HALF OF NCTRL NEBR.
ISOLATED DEVELOPMENT POSSIBLE FURTHER SOUTHWEST INTO LINCOLN AND
FRONTIER COUNTY.
STORM INITIATION THIS AFTERNOON WILL KEEP CHCS THIS EVENING ACROSS
THE ERN HALF OF FA EXITING FAR ERN ZONES AFTER 06Z. A FEW SEVERE
STORMS POSSIBLE THIS EVENING EAST OF VALENTINE THROUGH BURWELL WITH
A FEW STRONG STORMS POSSIBLE SOUTHWEST OF THIS LINE TO AROUND THE
NORTH PLATTE AREA.
UPPER RIDGING IS FORECAST ACROSS THE CNTRL AND NRN ROCKIES AS A
CLOSED LOW MOVES OVER THE HUDSON BAY REGION. SURFACE HIGH PRESSURE
WILL BUILD ACROSS THE NRN INTO THE CNTRL PLAINS OVERNIGHT. LOWS IN
WRN NEBR SLIGHTLY COOLER THAN RECENT NIGHTS RANGING FROM THE UPPER
50S TO LOWER 60S MOST AREAS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 328 AM CDT SUN AUG 9 2015
MODEL GUIDANCE REMAINS IN GOOD AGREEMENT WITH THE AMPLIFICATION OF
A UPPER LEVEL RIDGE ACROSS THE INTERMOUNTAIN WEST EARLY NEXT WEEK.
THIS WILL FAVOR A GENERAL NORTHWEST STEERING FLOW ACROSS THE HIGH
PLAINS AND ADJACENT SANDHILLS THROUGH THE ENTIRE WORK WEEK. WHILE
THE FORECAST AREA REMAINS ON THE EASTERN PERIPHERY OF THE BUILDING
RIDGE AND PLENTIFUL LOWER TROPOSPHERIC MOISTURE WILL BE IN
PLACE...PRECIPITATION CHANCE WILL BE MAINLY TIED TO THE HIGHER
TERRAIN OFF TO OUR WEST. PRECIPITATION CHANCES ARE NOT NIL HOWEVER
AS THE OCCASIONAL PASSAGE OF A WEAK PERTURBATION MAY BE SUFFICIENT
TO GENERATE/MAINTAIN AN ISOLATED THUNDERSTORM. ONE SUCH
OPPORTUNITY ARRIVES LATE MONDAY OR EARLY ON TUESDAY...BUT THE
TREND OF THE MODELS CONTINUES TO CONFINE THE CHANCES ONLY ACROSS
OUR FAR SOUTHWEST. OTHERWISE THE NEXT NOTABLE SHOT A QPF ARRIVES
LATE WEEK WHEN A SHORTWAVE BREAKSDOWN THE UPPER RIDGE AND FORCES A
COLD FRONT ACROSS THE PLAINS.
POST FRONTAL CONDITIONS WILL PROMOTE A SLIGHT COOL DOWN ON
MONDAY...BUT THEREAFTER DAYTIME TEMPERATURES ARE FORECAST TO
GRADUALLY INCREASE AS HIGH PRESSURE BUILDS TO THE SOUTHWEST OF THE
FORECAST AREA AND INCREASING THERMAL ADVECTION SPREADS EAST FROM
THE ROCKIES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1125 PM CDT SAT AUG 8 2015
THE NAM AND RAP MODELS SUGGEST AREAS OF FOG WILL FORM OVERNIGHT.
THE FORECAST USES THE NAM BUT NOTE THE RAP SHOWS THE FOG FORMING
FARTHER WEST ALONG HIGHWAY 61 WHILE THE NAM KEEPS THE FOG CLOSER
TO HIGHWAY 83.
VFR IS EXPECTED ALL AREAS BY 15Z SUNDAY. ISOLATED TO SCATTERED
TSTM COVERAGE IS EXPECTED LATE SUNDAY AFTN AND EARLY SUNDAY
EVENING ALONG AND EAST OF HIGHWAY 183.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ROBERG
SHORT TERM...ROBERG
LONG TERM...JACOBS
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1210 AM CDT SUN AUG 9 2015
.SHORT TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 315 PM CDT SAT AUG 8 2015
NO BIG CHANGES FROM PREVIOUS THINKING...MAIN CONCERN IS POTENTIAL
FOR SEVERE WEATHER AND HEAVY RAIN. THE SEVERE THREAT WOULD MAINLY
BE PRIOR TO 06Z TONIGHT AND THEN ALSO LATE SUN AFTN/SUN EVENING.
HEAVY RAIN THREAT IS PRIOR TO ABOUT 08Z TONIGHT...AND MAINLY IN
SWRN IA.
JET PATTERN AT 12Z SHOWED 300 MB WINDS OF 50 TO 80 KNOTS FROM SRN
CA INTO SD/ND/MN. A 500 MB LOW WAS OVER SRN ID AT 12Z BUT WATER
VAPOR IMAGERY/RECENT RUC MODEL INITIALIZATIONS SHOWED IT HAD
MOVED TO NEAR THE ID/MT/WY BORDER AREA AS OF EARLY THIS AFTN. THIS
WILL CONTINUE TO TRACK SLOWLY NEWD/EWD TONIGHT. THE 19Z KOAX
SOUNDING SHOWED THAT THE MID LEVELS HAD WARMED A BIT SINCE 12Z.
OUR 12Z 700 MB TEMP WAS 7.6 C BUT HAD INCREASED TO 10.7 C AS OF
19Z. 19Z SPC MESOANALYSIS SHOWED THAT THERE WAS STILL QUITE A BIT
OF LOWEST 100 MB CONVECTIVE INHIBITION (MLCIN) AND MOST OF THE
AREA WAS NOT OVERLY UNSTABLE. HIGHEST MLCAPE WAS NEAR THE KS
BORDER... AROUND 2000 J/KG. CAP WAS WEAKEST FROM SWRN KS INTO
PARTS OF CNTRL KS AS OF MID AFTN...NEAR AND AHEAD OF SFC LOW PRES
CENTER.
THERE REMAINS A CONDITIONAL THREAT OF SEVERE WEATHER FOR MOST OF
THE AREA. 0-6 KM SHEAR IS EXPECTED TO BE ADEQUATE FOR ROTATING
STORMS...BUT THERE IS SOME UNCERTAINTY AS TO WHEN AND WHERE
STRONG/SEVERE STORMS MAY FORM. THE MODELS OFFER VARYING SOLUTIONS.
ONE THING WE SAY IS THAT IT DOES APPEAR THAT BEST FOCUS WILL
SHIFT TO IA AND NRN MO LATER TONIGHT WITH A 30-50 KNOT LOW LEVEL
JET. LOWS SHOULD RANGE FROM MID 60S N TO AROUND 70 S.
WILL KEEP STORM CHANCES OVERNIGHT AND SUNDAY MORNING FOR AT LEAST
PARTS OF THE FCST AREA. BETTER POTENTIAL THOUGH APPEARS TO BE
LATER IN THE DAY ACRS OUR NRN ZONES...AS A FRONTAL SYSTEM DROPS
INTO THE AREA. KEPT SOME LOW POPS FOR LATE SUNDAY NIGHT AND MONDAY
BUT NOT IMPRESSED WITH RAIN POTENTIAL IN THOSE PERIODS FOR NOW...
ESPECIALLY MONDAY WHEN SURFACE RIDGE AXIS WILL BE BUILDING DOWN
ACROSS THE REGION.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 315 PM CDT SAT AUG 8 2015
PCPN CHANCES LOOK TO BE 14 PERCENT OR LESS FROM MONDAY NIGHT
ONWARD...SO FCST TEXT WILL NOT HAVE ANY MENTION OF TSTMS IN THOSE
PERIODS. 500 MB RIDGE IS EXPECTED TO BUILD W AND N FROM OK AND TX
MUCH OF THE WEEK...THEN FLATTEN A BIT BY NEXT WEEKEND AS TROUGH
MOVES EAST FROM THE PACIFIC NW AND NRN ROCKIES. LEFT A BLEND OF
GFS AND ECMWF TEMPS IN THE EXTENDED PERIOD...BUT HIGHS MAY END UP
BEING A BIT WARMER THAN THAT.
&&
.AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1207 AM CDT SUN AUG 9 2015
THUNDERSTORMS IN THE VICINITY OF KLNK/KOMA COULD LINGER FOR A
COUPLE HOURS AT TAF ISSUANCE. STORMS WILL DEFINITELY AFFECT
KOMA...BUT COULD VERY WELL MISS KLNK. KOFK REMAINS DRY. SOME MVFR
FOG COULD DEVELOP LATER TONIGHT AT ALL TAF SITES...AND COULD
TEMPORARILY BE IFR AT KOFK FOR A PERIOD. ADDITIONAL STORMS WILL BE
POSSIBLE AT KOFK VERY LATE IN THE TAF PERIOD...AFTER 10/02Z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...MILLER
LONG TERM...MILLER
AVIATION...DEWALD
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1126 PM CDT SAT AUG 8 2015
.SYNOPSIS...
ISSUED AT 333 PM CDT SAT AUG 8 2015
UA ANALYSIS FROM THIS MORNING HAD A FAIRLY ACTIVE
PATTERN ACROSS THE WESTERN HALF OF THE CONUS AND SRN CANADA. CLOSED
LOWS WERE NOTED OVER MANITOBA...AND OFF THE COAST OF BRITISH
COLUMBIA. ACROSS THE INTERMOUNTAIN WEST...SHORTWAVES WERE NOTED OVER
SRN IDAHO AND OVER CENTRAL CALIFORNIA. A WEAK SHORTWAVE WAS LOCATED
OVER SERN SD AND HAS SINCE PUSHED INTO SRN MN BASED ON WV IMAGERY.
ABUNDANT MID AND HIGH CLOUDINESS HAS STREAMED INTO THE FORECAST AREA
TDY FROM THE FOUR CORNERS IN ASSOCIATION WITH MONSOONAL MOISTURE
FROM MEXICO. THIS HIGH CLOUDINESS HAS ALLOWED LOW CLOUDINESS LEFT
OVER FROM THIS MORNING TO PERSIST INTO THE AFTERNOON HRS. THIS HAS
LED TO COOL TEMPS THIS AFTERNOON WITH READINGS MAINLY IN THE 70S.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 333 PM CDT SAT AUG 8 2015
VERY LIGHT WINDS EXPECTED TONIGHT ACROSS THE AREA...AND WITH THE WET
GROUND FROM RECENT RAINFALL...APPEARS TO BE A FAVORABLE SET UP FOR
AT LEAST PATCHY FOG OVERNIGHT. OTHERWISE...A STRONG SHORTWAVE ALOFT
IS CURRENTLY MOVING INTO SOUTHWEST MONTANA. EXPECT THE BEST FORCING
ASSOCIATED WITH THIS WAVE TO STAY NORTH AND WEST OF THE REGION
TONIGHT...BUT CANNOT RULE OUT A STRAY THUNDERSTORM ACROSS NORTHWEST
NEBRASKA IN CLOSER PROXIMITY TO THE SHORTWAVE.
THE WAVE ALOFT WILL WEAKEN SOME SUNDAY AS IT TURNS EAST AND MOVES
INTO THE DAKOTAS. A WEAK COLD FRONT/SURFACE TROUGH WILL TRY AND
ADVANCE EAST ACROSS THE AREA AS SURFACE LOW PRESSURE DEEPENS A BIT
IN CENTRAL SOUTH DAKOTA. THIS WILL BE A FOCUS FOR A FEW TSTMS LATE
SUNDAY AFTERNOON...WITH THE BEST CHANCES ACROSS EASTERN PORTIONS OF
NORTH CENTRAL NEBRASKA WHERE SOMEWHAT BETTER UPPER LEVEL FORCING
WILL BE LOCATED. AGREE WITH THE SPC SLIGHT RISK FOR SEVERE STORMS
ACROSS HOLT AND BOYD COUNTIES...AS MLCAPE APPROACHES 1500 TO 2500
J/KG ALONG AND AHEAD OF THE FRONT. AMPLE WIND SHEAR WOULD SUPPORT A
SUPERCELL OR TWO IF STORMS DEVELOP...WITH LARGE HAIL AND DAMAGING
WINDS THE MAIN THREATS.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 333 PM CDT SAT AUG 8 2015
MID RANGE...SUNDAY NIGHT THROUGH TUESDAY...IN THE MID
RANGE...PRECIPITATION CHANCES SUNDAY NIGHT...AND MONDAY NIGHT ARE
THE MAIN FORECAST CHALLENGES. FOR SUNDAY NIGHT...A COLD FRONTAL
BOUNDARY WILL PUSH INTO NORTHWESTERN AROUND 00Z MONDAY...THEN
CENTRAL NEBRASKA DURING THE EVENING HOURS...EXITING THE CWA AROUND
THE 06Z MONDAY TIME FRAME. SOUTH OF THE FRONT A DRYLINE WILL EXTEND
FROM ROUGHLY NORTH PLATTE...TO AINSWORTH...WHERE SB CAPES APPROACH
3000 J/KG. DECENT MOISTURE CONVERGENCE ALONG THE DRYLINE...COUPLED
WITH A WEAK CAP WILL LEAD TO THE DEVELOPMENT OF THUNDERSTORMS SUNDAY
EVENING. AS THIS ACTIVITY MIGRATES EAST...ABUNDANT DEEP LAYER SHEAR
OF 40 TO 45 KTS EXISTS EAST OF THE DRYLINE SUNDAY EVENING...WHICH
WOULD SUPPORT STRONG STORMS IN THE CENTRAL AND SOUTH...AND SOME
SEVERE STORMS IN THE NERN CWA...WHERE SHEAR IS STRONGER AND
AVAILABLE CAPE IS GREATER. IN ADDITION...INSTABILITY IN THE MID
LEVELS IS STRONGER IN THE NERN CWA AS IT WILL BE LOCATED IN CLOSER
PROXIMITY TO THE H5 SHORTWAVE. DECIDED TO KEEP IN A MENTION OF
SLIGHT CHANCE POPS ALONG AND EAST OF THE DRYLINE...AND INCREASED
POPS TO 30 TO 40 PERCENT IN THE NORTHEAST WHERE BETTER DYNAMICS AND
INSTABILITY ALOFT EXISTS. THE COLD FRONT WILL DROP SOUTH INTO KANSAS
OVERNIGHT...AND REMAIN OFF TO THE SOUTH OF THE FORECAST AREA FOR
MONDAY AS SURFACE HIGH PRESSURE BUILDS INTO NORTHERN NEBRASKA. THIS
WILL LEAD TO COOLER TEMPS WITH HIGHS AROUND 80 MONDAY. FOR MONDAY
NIGHT...THE GFS AND NAM SOLNS...DO INITIATE CONVECTION ALONG THE
HIGH PLAINS OF COLORADO AND WYOMING MONDAY AFTERNOON...SOME OF WHICH
BEGINS TO APPROACH THE FAR WESTERN AND SWRN CWA LATER IN THE
EVENING. INHERITED FCST HAD PRECIP CHANCES AS FAR EAST AS HIGHWAY
83. BASED ON THE MODEL TRENDS...TRIMMED POPS BACK...CONFINING THEM
TO THE SERN PANHANDLE AND FAR SWRN NEBRASKA. ON TUESDAY...ANOTHER
ROUND OF THUNDERSTORMS WILL DEVELOP ACROSS THE FRONT RANGE AND HIGH
PLAINS OF COLORADO AND WYOMING. HOWEVER...H5 WINDS WILL TURN MORE TO
THE NORTHWEST AS HIGH PRESSURE BEGINS TO BUILD INTO NEW MEXICO AND
COLORADO. WITH NOT MUCH IN THE WAY OF CONVECTION EXPECTED OVER THE
BLACK HILLS...THINKING MOST LEE SIDE CONVECTION TUESDAY SHOULD STAY
WEST OF THE FORECAST AREA AND HAVE OPTED FOR A DRY FCST.
LONG RANGE...TUESDAY NIGHT THROUGH SATURDAY...IN THE
EXTENDED...RIDGING IS STILL ON TRACK TO BUILD INTO THE CENTRAL AND
NORTHERN ROCKIES...AS WELL AS THE HIGH PLAINS BY MIDWEEK. HIGH
PRESSURE AT THE BASE OF THE RIDGE...WILL BUILD NORTH INTO COLORADO
LATE IN THE WEEK. THIS WILL RESULT IN DRY CONDS AND INCREASING
TEMPERATURES ACROSS THE FORECAST AREA. AFTER HIGHS IN THE MID TO
UPPER 80S WEDNESDAY...READINGS WILL REACH THE 90S BY THE LATTER
HALF OF NEXT WEEK. THE RIDGE WILL BEGIN TO FLATTEN ACROSS THE
ROCKIES FRIDAY NIGHT AS A DECENT SHORTWAVE TROUGH TRACKS ACROSS
SRN CANADA. THIS FEATURE WILL FORCE A COLD FRONT ACROSS THE
DAKOTAS SATURDAY...THE SRN FRINGES OF WHICH...WILL APPROACH THE
NWRN CWA. DECIDED TO INTRODUCE SOME POPS IN THE NWRN CWA SATURDAY
TO ACCOUNT FOR THE FRONT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1125 PM CDT SAT AUG 8 2015
THE NAM AND RAP MODELS SUGGEST AREAS OF FOG WILL FORM OVERNIGHT.
THE FORECAST USES THE NAM BUT NOTE THE RAP SHOWS THE FOG FORMING
FARTHER WEST ALONG HIGHWAY 61 WHILE THE NAM KEEPS THE FOG CLOSER
TO HIGHWAY 83.
VFR IS EXPECTED ALL AREAS BY 15Z SUNDAY. ISOLATED TO SCATTERED
TSTM COVERAGE IS EXPECTED LATE SUNDAY AFTN AND EARLY SUNDAY
EVENING ALONG AND EAST OF HIGHWAY 183.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CLB
SHORT TERM...TAYLOR
LONG TERM...CLB
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
356 AM EDT SUN AUG 9 2015
.SYNOPSIS...
ANOTHER NICE DAY IS EXPECTED ACROSS THE NORTH COUNTRY
WITH MAINLY DRY CONDITIONS AND NEAR NORMAL TEMPERATURES. AN ISOLATED
SHOWER OR SPRINKLE IS POSSIBLE ACROSS NORTHEAST VERMONT THIS
AFTERNOON. OTHERWISE...DRY CONDITIONS WITH SLIGHTLY ABOVE NORMAL
TEMPERATURES ARE FORECASTED FOR MONDAY...BEFORE SHOWERS ARRIVE ON
MONDAY NIGHT INTO TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 345 AM EDT SUNDAY...FORECAST FOCUS TODAY WILL BE CHANCE FOR
AN ISOLATED SHOWER ACROSS THE NORTHEAST KINGDOM OF VT. CRNT WATER
VAPOR SHOWS MID/UPPER LVL TROF CONTS...WITH WEAK S/W ENERGY DIVING
SOUTH FROM EASTERN CANADA. ALSO...WATER VAPOR SHOWS VERY DRY AIR
AHEAD OF THIS SYSTEM...SO ANY PRECIP CHCS TODAY WILL BE VERY
ISOLATED AND CONFINED TO THE NORTHEAST KINGDOM OR MTNS OF NORTHERN
VT. BTV 4KM IS MOST AGGRESSIVE WITH SHOWING QPF AND ASSOCIATED
COMPOSITE REFLECTIVITY RETURNS ACROSS MOST OF THE HIGHER TRRN OF VT
THIS AFTN...BUT GIVEN PROGGED SOUNDING MOISTURE PROFILES...THINKING
THIS IS OVERDONE. WL USE A BLEND OF NAM/GFS AND HRRR TO MENTION SCHC
WITH A SMALL AREA OF CHC POPS ACROSS ESSEX COUNTY VT. REST OF CWA
WILL REMAIN DRY. TEMPS WILL BE SEVERAL DEGREES WARMER THAN YESTERDAY
WITH HIGHS GENERALLY IN THE 70S TO NEAR 80F.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
AS OF 345 AM EDT SUNDAY...OUR NICE PERIOD OF DRY
WEATHER WILL BE COMING TO AN END BY TUESDAY...AS MID/UPPER LVL TROF
AND ASSOCIATED SFC LOW PRES IMPACT THE NE CONUS. FOR MONDAY...BEST
850 TO 500MB MOISTURE IS WEST OF OUR CWA THRU 00Z..ALONG WITH
FORCING ASSOCIATED WITH INITIAL 5H VORT. WILL CONT TO MENTION CHC
POPS TWD 00Z TUESDAY ACROSS THE SLV AND WESTERN DACKS. PROGGED 85H
TEMPS WARM BTWN 12-14C BY 18Z MONDAY...SUPPORTING M/U 70S MTN TOWNS
TO L/M 80S WARMER VALLEYS.
OVERALL...NAM/GFS AND ECMWF HAVE COME INTO PRETTY GOOD AGREEMENT
WITH HANDLING THE DEEPENING OF MID/UPPER LVL TROF ACROSS THE GREAT
LAKES AND SFC LOW PRES TRACKING FROM THE OHIO VALLEY MONDAY NIGHT
INTO THE SLV BY TUES. IN ADDITION...MODELS HAVE TRENDED SEVERAL
HOURS SLOWER WITH THE PRECIP ARRIVE ON MONDAY NIGHT INTO TUESDAY
ACROSS OUR CWA...WITH HEAVIEST QPF AXIS OF UP TO 1.0 OF RAIN
EXPECTED OVER NORTHERN NY BY TUES AFTN. LOW LEVEL FORCING/ ADVECTION
OF MOISTURE IS IMPRESSIVE ASSOCIATED WITH NOSE OF 85H JET OF 45 TO
50 KNOTS IMPACTING OUR CWA BY 12Z TUESDAY. GFS/NAM SHOW A STRONG
BAND OF 850 TO 700MB FGEN FORCING...ALONG WITH GOOD LVLL MOISTURE
CONVERGENCE LIFTING FROM SW TO NE ACRS OUR CWA BTWN 09Z AND 18Z
TUESDAY.
HAVE NOTED SOME HIGHER RESOLUTION MODELS SHOWING IMPACTS OF
SE TO SOUTHWEST WINDS ON THE ASSOCIATED QPF FIELDS WITH SOME
SHADOWING OVER THE CPV AND PARTS OF THE NEK. GIVEN THE MOISTURE FEED
WITH PWS AROUND 1.50" AND GOOD UPPER LEVEL DYNAMICS WITH APPROACHING
TROF AND HEIGHT FALLS...A WIDESPREAD RAINFALL IS VERY LIKELY LATE
MONDAY NIGHT INTO TUESDAY. WILL CONT THE TREND AND MENTION CAT POPS
ACRS OUR CWA...BUT TRRN WILL INFLUENCE QPF FIELDS....WITH HIGHEST
VALUES OF UP TO 1.0 OCCURRING ACRS THE NORTHERN NY/HIGH PEAKS
REGION...GIVEN THE LLVL JET ORIENTATION. MEANWHILE...VALUES ACROSS
VT WILL RANGE FROM 0.25 TO 0.75" WITH HIGHEST AMOUNTS ON SE UPSLOPE
AREAS OF THE GREEN MTNS.
SOUNDINGS SHOW RIDGETOP WINDS BTWN 45 AND 50 KNOTS ON TUESDAY
MORNING...BUT INVERSION LEVEL IS AROUND 2000 FT....SUPPORTING
MIXED LAYER WINDS TO THE SURFACE UP TO 35 MPH OR SO ALONG THE
WESTERN SLOPES AND HIGHER TRRN. TEMPS TUES WILL BE TRICKY WITH
1000 TO 500MB THICKNESS RIDGE OVERHEAD...BUT LOTS OF CLOUDS AND
PRECIP AROUND. THINKING A FEW BREAKS WILL DEVELOP IN MID LVL DRY
SLOT OVER THE SLV/WESTERN DACKS AND THIS AREA WILL REACH
80F...WHILE MOST OF THE OTHER SITES STAY IN THE M/U 60S MTNS TO
L/M 70S CPV/SOUTHERN VT.
A RUMBLE OF THUNDER ASSOCIATED WITH THE DYNAMICS CANNOT BE RULED
OUT ON TUESDAY MORNING...WITH ANOTHER CHC OF A RUMBLE ON TUES AFTN
IN THE WARM SECTOR OVER SLV. ALSO...NOTED WEAK ELEVATED
INSTABILITY LAYER WITH ML CAPE VALUES AROUND 400 J/KG ON MONDAY
NIGHT/TUESDAY MORNING...ASSOCIATED WITH NOSE OF 85H JET AND STRONG
LLVL WAA.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 354 AM EDT SUNDAY...RATHER ACTIVE WEATHER WITH CHANCE OF
SHOWERS FOR MUCH OF THE PERIOD AS UPPER LEVEL TROUGH REMAINS OVER
THE EAST.
WEAK SURFACE BOUNDARY WILL MOVE SLOWLY EAST OF THE AREA TUESDAY
NIGHT...WITH HIGHEST PRECIPITABLE WATER VALUES SHIFTING TO THE EAST
AS WELL. UPPER LEVEL LOW LAGS BEHIND HOWEVER...SO WHILE HIGHEST
CHANCE OF SHOWERS WILL BE DURING THE EVENING...THERE WILL BE A
CONTINUED CHANCE FOR A FEW SHOWERS DURING THE OVERNIGHT AS WELL.
WITH UPPER LEVEL LOW AND ASSOCIATED COLD POOL ALOFT STILL OVER THE
REGION ON WEDNESDAY...WE CAN EXPECT MORE CLOUDS AND A CONTINUED
CHANCE OF SHOWERS. WEST TO NORTHWEST UPSLOPE FLOW WILL HELP PROVIDE
SOURCE OF LIFT FOR BETTER COVERAGE OVER THE HIGHER TERRAIN. LIMITED
INSTABILITY...BUT AN ISOLATED THUNDERSTORM ALSO POSSIBLE.
UPPER TROUGH SLOW TO DEPART THURSDAY...SO STILL CHANCE OF A FEW
SHOWERS. DRIER CONDITIONS LATER THURSDAY INTO FRIDAY MORNING WITH
SHORTWAVE RIDGING ALOFT AT 500MB. FROM FRIDAY ONWARD YET ANOTHER
UPPER LEVEL TROUGH WILL APPROACH FROM THE NORTHERN GREAT LAKES
REGION AND RE-ESTABLISH THE EASTERN US TROUGH AND A CHANCE FOR MORE
SHOWERS AND A FEW WIDELY SCATTERED STORMS.
AS FOR TEMPS...MAX TEMPS WILL AVERAGE SEVERAL DEGREES BELOW NORMAL
WITH HIGHS MAINLY IN THE 70S...PERHAPS AROUND 80 IN SPOTS FRIDAY AND
SATURDAY. MINS WILL BE IN THE 50S TO AROUND 60...GENERALLY WITHIN
A FEW DEGREES OF NORMAL FOR MID AUGUST.
&&
.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
THROUGH 06Z MONDAY...MAINLY VFR EXPECTED...WITH THE EXCEPTION OF
SOME IFR/LIFR FOG/BR LATE TONIGHT AND EARLY SUNDAY MORNING AT
SLK/MSS/MPV. BKN HIGH CIRRUS DECK WILL PROGRESS EASTWARD
OVERNIGHT...SLOWLY CLEARING THE REGION BETWEEN THROUGH 11Z. WITH
THE CLEARING WILL COME THE POTENTIAL FOR FOG/BR DEVELOPMENT.
GREATEST LIKELIHOOD TO SEE LIFR FOG WILL BE AT SLK & MPV...WITH
THE POSSIBILITY AT MSS AS WELL. FOG/BR LIFTS BY AROUND 12Z WITH
CLEAR SKIES GIVING WAY TO A DEVELOPING CU FIELD IN THE
AFTERNOON...WITH ALL SITES VFR. WINDS LIGHT AND LOCALLY VARIABLE
OVERNIGHT (EXCEPT SE AT RUT WITH DRAINAGE WIND) BECOME GENERALLY
NORTHERLY FROM 4-7 KNOTS ON SUNDAY...BUT WITH LIGHT FLOW...THEY
WILL BE LOCALLY VARIABLE.
OUTLOOK 06Z MONDAY THROUGH THURSDAY...
06Z MONDAY THROUGH 00Z TUESDAY...VFR EXCEPT LOCAL IFR WITH OVERNIGHT
PATCHY FOG MAINLY MPV AND SLK.
00Z TUESDAY THROUGH 00Z WEDNESDAY...DETERIORATING CONDITIONS
LIKELY (MVFR POSSIBLE IFR) WITH PERIODS OF RAIN SHOWERS AND
STRATUS.
00Z WEDNESDAY ONWARD...VFR WITH PERIODS OF MVFR IN LINGERING
SCATTERED SHOWERS. SHOWERS DIMINISHING THURSDAY.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...TABER
NEAR TERM...TABER
SHORT TERM...TABER
LONG TERM...RJS
AVIATION...RJS/MUCCILLI
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
348 AM EDT SUN AUG 9 2015
.SYNOPSIS...
ANOTHER NICE DAY IS EXPECTED ACROSS THE NORTH COUNTRY
WITH MAINLY DRY CONDITIONS AND NEAR NORMAL TEMPERATURES. AN ISOLATED
SHOWER OR SPRINKLE IS POSSIBLE ACROSS NORTHEAST VERMONT THIS
AFTERNOON. OTHERWISE...DRY CONDITIONS WITH SLIGHTLY ABOVE NORMAL
TEMPERATURES ARE FORECASTED FOR MONDAY...BEFORE SHOWERS ARRIVE ON
MONDAY NIGHT INTO TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 345 AM EDT SUNDAY...FORECAST FOCUS TODAY WILL BE CHANCE FOR
AN ISOLATED SHOWER ACROSS THE NORTHEAST KINGDOM OF VT. CRNT WATER
VAPOR SHOWS MID/UPPER LVL TROF CONTS...WITH WEAK S/W ENERGY DIVING
SOUTH FROM EASTERN CANADA. ALSO...WATER VAPOR SHOWS VERY DRY AIR
AHEAD OF THIS SYSTEM...SO ANY PRECIP CHCS TODAY WILL BE VERY
ISOLATED AND CONFINED TO THE NORTHEAST KINGDOM OR MTNS OF NORTHERN
VT. BTV 4KM IS MOST AGGRESSIVE WITH SHOWING QPF AND ASSOCIATED
COMPOSITE REFLECTIVITY RETURNS ACROSS MOST OF THE HIGHER TRRN OF VT
THIS AFTN...BUT GIVEN PROGGED SOUNDING MOISTURE PROFILES...THINKING
THIS IS OVERDONE. WL USE A BLEND OF NAM/GFS AND HRRR TO MENTION SCHC
WITH A SMALL AREA OF CHC POPS ACROSS ESSEX COUNTY VT. REST OF CWA
WILL REMAIN DRY. TEMPS WILL BE SEVERAL DEGREES WARMER THAN YESTERDAY
WITH HIGHS GENERALLY IN THE 70S TO NEAR 80F.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
AS OF 345 AM EDT SUNDAY...OUR NICE PERIOD OF DRY
WEATHER WILL BE COMING TO AN END BY TUESDAY...AS MID/UPPER LVL TROF
AND ASSOCIATED SFC LOW PRES IMPACT THE NE CONUS. FOR MONDAY...BEST
850 TO 500MB MOISTURE IS WEST OF OUR CWA THRU 00Z..ALONG WITH
FORCING ASSOCIATED WITH INITIAL 5H VORT. WILL CONT TO MENTION CHC
POPS TWD 00Z TUESDAY ACROSS THE SLV AND WESTERN DACKS. PROGGED 85H
TEMPS WARM BTWN 12-14C BY 18Z MONDAY...SUPPORTING M/U 70S MTN TOWNS
TO L/M 80S WARMER VALLEYS.
OVERALL...NAM/GFS AND ECMWF HAVE COME INTO PRETTY GOOD AGREEMENT
WITH HANDLING THE DEEPENING OF MID/UPPER LVL TROF ACROSS THE GREAT
LAKES AND SFC LOW PRES TRACKING FROM THE OHIO VALLEY MONDAY NIGHT
INTO THE SLV BY TUES. IN ADDITION...MODELS HAVE TRENDED SEVERAL
HOURS SLOWER WITH THE PRECIP ARRIVE ON MONDAY NIGHT INTO TUESDAY
ACROSS OUR CWA...WITH HEAVIEST QPF AXIS OF UP TO 1.0 OF RAIN
EXPECTED OVER NORTHERN NY BY TUES AFTN. LOW LEVEL FORCING/ ADVECTION
OF MOISTURE IS IMPRESSIVE ASSOCIATED WITH NOSE OF 85H JET OF 45 TO
50 KNOTS IMPACTING OUR CWA BY 12Z TUESDAY. GFS/NAM SHOW A STRONG
BAND OF 850 TO 700MB FGEN FORCING...ALONG WITH GOOD LVLL MOISTURE
CONVERGENCE LIFTING FROM SW TO NE ACRS OUR CWA BTWN 09Z AND 18Z
TUESDAY.
HAVE NOTED SOME HIGHER RESOLUTION MODELS SHOWING IMPACTS OF
SE TO SOUTHWEST WINDS ON THE ASSOCIATED QPF FIELDS WITH SOME
SHADOWING OVER THE CPV AND PARTS OF THE NEK. GIVEN THE MOISTURE FEED
WITH PWS AROUND 1.50" AND GOOD UPPER LEVEL DYNAMICS WITH APPROACHING
TROF AND HEIGHT FALLS...A WIDESPREAD RAINFALL IS VERY LIKELY LATE
MONDAY NIGHT INTO TUESDAY. WILL CONT THE TREND AND MENTION CAT POPS
ACRS OUR CWA...BUT TRRN WILL INFLUENCE QPF FIELDS....WITH HIGHEST
VALUES OF UP TO 1.0 OCCURRING ACRS THE NORTHERN NY/HIGH PEAKS
REGION...GIVEN THE LLVL JET ORIENTATION. MEANWHILE...VALUES ACROSS
VT WILL RANGE FROM 0.25 TO 0.75" WITH HIGHEST AMOUNTS ON SE UPSLOPE
AREAS OF THE GREEN MTNS.
SOUNDINGS SHOW RIDGETOP WINDS BTWN 45 AND 50 KNOTS ON TUESDAY
MORNING...BUT INVERSION LEVEL IS AROUND 2000 FT....SUPPORTING
MIXED LAYER WINDS TO THE SURFACE UP TO 35 MPH OR SO ALONG THE
WESTERN SLOPES AND HIGHER TRRN. TEMPS TUES WILL BE TRICKY WITH
1000 TO 500MB THICKNESS RIDGE OVERHEAD...BUT LOTS OF CLOUDS AND
PRECIP AROUND. THINKING A FEW BREAKS WILL DEVELOP IN MID LVL DRY
SLOT OVER THE SLV/WESTERN DACKS AND THIS AREA WILL REACH
80F...WHILE MOST OF THE OTHER SITES STAY IN THE M/U 60S MTNS TO
L/M 70S CPV/SOUTHERN VT.
A RUMBLE OF THUNDER ASSOCIATED WITH THE DYNAMICS CANNOT BE RULED
OUT ON TUESDAY MORNING...WITH ANOTHER CHC OF A RUMBLE ON TUES AFTN
IN THE WARM SECTOR OVER SLV. ALSO...NOTED WEAK ELEVATED
INSTABILITY LAYER WITH ML CAPE VALUES AROUND 400 J/KG ON MONDAY
NIGHT/TUESDAY MORNING...ASSOCIATED WITH NOSE OF 85H JET AND STRONG
LLVL WAA.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 247 PM EDT SATURDAY...RATHER ACTIVE IF NOT SOGGY WEATHER
FOR MUCH OF THE EXTENDED PERIOD AS FLOW AT 500MB EVOLVES INTO A
HIGH AMPLITUDE TROUGH IN THE EAST.
FORECAST MODELS COMING MORE IN LINE WITH EACH OTHER WITH UPPER
TROUGH SETTLING IN ACROSS THE NORTHEAST AND SURFACE LOW SLOWLY
MOVING THROUGH THE AREA DURING THE DAY TUESDAY. AREA OF SHOWERS
ALONG AND AHEAD OF THE FRONT WILL SLOW MOVE WEST TO EAST. SMALL
CHANCE FOR SOME THUNDER WITH SURFACE BASED CAPE 150-200 J/KG, AND
THUNDER MENTION IN THE FORECAST IS SECONDARY TO RAIN. PRECIPITABLE
WATER INCREASES OVER 1.5 INCHES IN THE SOUTHERLY FLOW AHEAD OF THE
FRONT...AND MOST MODEL GUIDANCE SHOWS AROUND .50 TO .75 INCH OF
RAIN DURING THE DAY ON TUESDAY. NOT A HYDRO THREAT BUT WILL BE A
WET DAY.
TUESDAY NIGHT INTO WEDNESDAY THE WEAK SURFACE BOUNDARY MOVES EAST
OF THE REGION...BUT UPPER LOW LAGS BEHIND. COLD POOL ALOFT WILL BE
OVER THE AREA WEDNESDAY PROVIDING INSTABILITY TO GENERATE
ADDITIONAL SHOWERS, AND WEST TO NORTHWEST UPSLOPE FLOW WILL HELP
PROVIDE SOURCE OF LIFT FOR BETTER COVERAGE OVER THE HIGHER
TERRAIN. UPPER TROUGH SLOW TO DEPART THURSDAY...SO STILL CHANCE OF
A FEW SHOWERS. SHORTWAVE RIDGING ALOFT AT 500MB, SO IF THERE IS
ANY TIME WHEN IT SHOULDN`T RAIN WILL BE LATE THURSDAY INTO EARLY
FRIDAY. FROM FRIDAY ONWARD YET ANOTHER UPPER LEVEL TROUGH WILL
APPROACH FROM THE NORTHERN GREAT LAKES REGION AND RE- ESTABLISH
THE EASTERN US TROUGH AND A CHANCE FOR MORE SHOWERS.
AS FOR TEMPS...MAX TEMPS WILL AVERAGE SEVERAL DEGREES BELOW
NORMAL WITH HIGHS MAINLY IN THE 70S. MINS WILL BE ABOVE NORMAL
EARLY IN THE PERIOD WITH READINGS IN THE UPPER 50S TO MID
60S...THEN RETURN TO NEAR SEASONAL WITH LOWS MAINLY IN THE 50S.
&&
.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
THROUGH 06Z MONDAY...MAINLY VFR EXPECTED...WITH THE EXCEPTION OF
SOME IFR/LIFR FOG/BR LATE TONIGHT AND EARLY SUNDAY MORNING AT
SLK/MSS/MPV. BKN HIGH CIRRUS DECK WILL PROGRESS EASTWARD
OVERNIGHT...SLOWLY CLEARING THE REGION BETWEEN THROUGH 11Z. WITH
THE CLEARING WILL COME THE POTENTIAL FOR FOG/BR DEVELOPMENT.
GREATEST LIKELIHOOD TO SEE LIFR FOG WILL BE AT SLK & MPV...WITH
THE POSSIBILITY AT MSS AS WELL. FOG/BR LIFTS BY AROUND 12Z WITH
CLEAR SKIES GIVING WAY TO A DEVELOPING CU FIELD IN THE
AFTERNOON...WITH ALL SITES VFR. WINDS LIGHT AND LOCALLY VARIABLE
OVERNIGHT (EXCEPT SE AT RUT WITH DRAINAGE WIND) BECOME GENERALLY
NORTHERLY FROM 4-7 KNOTS ON SUNDAY...BUT WITH LIGHT FLOW...THEY
WILL BE LOCALLY VARIABLE.
OUTLOOK 06Z MONDAY THROUGH THURSDAY...
06Z MONDAY THROUGH 00Z TUESDAY...VFR EXCEPT LOCAL IFR WITH OVERNIGHT
PATCHY FOG MAINLY MPV AND SLK.
00Z TUESDAY THROUGH 00Z WEDNESDAY...DETERIORATING CONDITIONS
LIKELY (MVFR POSSIBLE IFR) WITH PERIODS OF RAIN SHOWERS AND
STRATUS.
00Z WEDNESDAY ONWARD...VFR WITH PERIODS OF MVFR IN LINGERING
SCATTERED SHOWERS. SHOWERS DIMINISHING THURSDAY.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...TABER
NEAR TERM...TABER
SHORT TERM...TABER
LONG TERM...HANSON
AVIATION...RJS/MUCCILLI
AREA FORECAST DISCUSSION
NWS BISMARCK ND
354 AM CDT SUN AUG 9 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM CDT SUN AUG 9 2015
THE MAIN FOCUS TODAY IS ON SHOWERS AND THUNDERSTORMS ALONG AND
SOUTH OF U.S. HIGHWAY 2.
SO FAR THIS MORNING...THE 00 UTC NAM ARW/NAM NMM AND THE LAST FEW
RUNS OF THE HRRR HAVE A GOOD HANDLE ON SHOWERS INITIATING IN
SOUTHWEST AND SOUTH CENTRAL NORTH DAKOTA AS ONGOING CONVECTION
SHIFTS INTO NORTHEASTERN SOUTH DAKOTA.
THUS FAR...THUNDERSTORMS HAVE BEEN CONFINED TO SOUTH DAKOTA...BUT
THAT SHOULD CHANGE AROUND NOON AS SOLAR HEATING HELPS
DESTABILIZATION BENEATH THE MID LEVEL LOW OVER EASTERN MONTANA IN
08 UTC WATER VAPOR IMAGERY. BASED ON HIRES MODELS...AND VALIDATED
BY THE STORM PREDICTION CENTER CONVECTIVE OUTLOOKS...THE SEVERE
THREAT IS LOW.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 334 AM CDT SUN AUG 9 2015
MODELS ARE IN GOOD AGREEMENT BUILDING STRONG UPPER LEVEL RIDGE
ACROSS THE WEST EARLY IN THE WEEK WITH THE RIDGE AXIS SLOWLY
MOVING EAST. DRY WEATHER EXPECTED THROUGH MOST OF THE WEEK WITH
TEMPERATURES BUILDING TO MUCH ABOVE NORMAL BY MID-WEEK...UPPER
90S POSSIBLE WEST BY WEDNESDAY. SOME MODEL DIFFERENCES DEVELOP BY
LATE WEEK AS STRONG UPPER LEVEL LOW MOVES INTO THE PAC NW WITH THE
UPPER LEVEL RIDGE AXIS SHIFTING EAST OF THE NORTHERN PLAINS BY
EARLY WEEKEND. MAX TEMPS MODERATE BY LATE WEEK...STILL ABOVE
NORMAL IN THE UPPER 80S...WITH INCREASING CHANCES OF
SHOWERS/THUNDERSTORMS INTO THE WEEKEND AS UPPER LEVEL RIDGE BREAKS
DOWN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 334 AM CDT SUN AUG 9 2015
THE MAIN HAZARD TO AVIATION WILL BE POSSIBLE MVFR CONDITIONS IN
CLOUDS AND RAIN ACROSS SOUTHWEST NORTH DAKOTA TODAY. OTHERWISE
CONDITIONS WILL REMAIN VFR.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SCHECK
LONG TERM...JNS
AVIATION...SCHECK
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1244 AM CDT SUN AUG 9 2015
.UPDATE...
ISSUED AT 1238 AM CDT SUN AUG 9 2015
THE MAIN FOCUS THIS MORNING IS ON RAIN SHOWERS.
SCATTERED LIGHT TO MODERATE RAIN SHOWERS ARE MEANDERING EASTWARD
ALONG AND SOUTH OF I-94. THE 02-04 UTC HRRR RUNS SEEM TO HAVE A
GOOD HANDLE ON THE TIMING AND EVOLUTION OF THIS EVENT...SO UPDATED
PRECIPITATION CHANCES WERE DERIVED FROM A TIME-LAGGED BLEND OF
THOSE RUNS.
UPDATE ISSUED AT 956 PM CDT SAT AUG 8 2015
MADE SOME POP CHANGES USING THE LATEST HRRR RUNS AND TRENDING
EARLY TOWARD THE RADAR. LIGHTNING IS SLOWLY CREEPING TOWARD THE
BORDER. LOOKS LIKE MUCH OF THE EARLY PRECIP SUFFERED FROM WEAK
FORCING AND EVAPORATION BELOW CLOUDS BASE. NOW LOOKS LIKE MORE
SUBSTANTIAL SHOWERS/THUNDERSTORMS WILL MOVE INTO SOUTHWEST ND AS
MIDNIGHT APPROACHES.
UPDATE ISSUED AT 646 PM CDT SAT AUG 8 2015
RADAR TRENDS SHOW SEVERAL BANDS OF PRECIPITATION MOVING INTO SOUTHWEST
AND SOUTH CENTRAL NORTH DAKOTA. SO FAR VERY LITTLE IF ANY APPEARS
TO BE REACHING THE GROUND AS OF 630 PM CDT. ONE REASON MAY BE THE
DRY SUBCLOUD LAYER RESULTING IN CONSIDERABLE EVAPORATION. EVENTUALLY
THERE WILL BE RAIN SOUTHWEST. WILL CONTINUE THE HIGHER POPS TREND
WITH TIME THIS EVENING ACROSS THE FAR SOUTHWEST AND SOUTH CENTRAL.
LITTLE RAIN WILL REACH THE AREA NORTH OF I94 EVEN THROUGH MUSH OF
THE DAY TOMORROW. SO FAR INSTABILITY IS SLIM SO REDUCED THE TREAT
FOR THUNDERSTORMS TO WIDELY SCATTERED.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 238 PM CDT SAT AUG 8 2015
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE CHANCES FOR
SHOWERS AND ISOLATED THUNDERSTORMS SOUTHWEST THIS
AFTERNOON...EXPANDING INTO THE SOUTH CENTRAL TONIGHT...WITH
THUNDERSTORM CHANCES CONTINUING ON SUNDAY ACROSS THE SOUTH.
CURRENTLY...TRANSITIONAL FLOW ALOFT WAS OCCURRING OVER SOUTHWESTERN
NORTH DAKOTA...FROM ZONAL/WEAK RIDGE ALOFT TO SOUTHWESTERLY. THE
STACKED LOW PRESSURE SYSTEM OVER MANITOBA CONTINUED MOVING EAST
TODAY AS AN UPPER LEVEL SHORTWAVE TROUGH PROGRESSES NORTHEASTWARD
OUT OF IDAHO ACROSS WYOMING AND MONTANA. THIS IDAHO SHORTWAVE WAS
UNDERCUTTING A LARGER WESTERN RIDGE THAT EXTENDED NORTHWARD OVER THE
CANADIAN ROCKIES. MEANWHILE AT THE SURFACE...A COLD FRONT EXTENDING
FROM THE MANITOBA LOW HAD MOVED THROUGH ALL OF WESTERN AND MOST OF
CENTRAL NORTH DAKOTA. DEWPOINTS WERE IN THE 40S IN THE WEST...50S
CENTRAL...WITH A VERY HUMID 70 READING AT OAKES SOUTH OF JAMESTOWN.
THE MODELS ARE IN AGREEMENT THAT THE ZONAL/WEAK RIDGING ALOFT WAS
SLOWING THE PROGRESSION OF SHOWERS INTO SOUTHWESTERN NORTH DAKOTA
EARLIER TODAY. LATEST REGIONAL RADAR LOOPS INDICATE LIGHT SHOWERS
MOVING INTO THE BOWMAN/HETTINGER AREAS. CONFIDENCE IS LOW AS TO
WHETHER THIS REFLECTS SHOWERS REACHING THE GROUND OR VIRGA. IN ANY
CASE...THE MODELS ARE INDICATING THE VIGOROUS SHORTWAVE MOVING INTO
THE SOUTHWEST WILL CONTINUE TO PROVIDE MID-LEVEL BASED SHOWERS
THROUGH TONIGHT AND INTO SUNDAY. AT SOME POINT...SHOWERS SHOULD
REACH THE GROUND AS THE CONVECTION CONTINUES ITS ADVANCEMENT AND
FORCING INCREASES.
THE MODELS ALSO INDICATE THAT RIDGING ALOFT OVER THE CANADIAN
ROCKIES SHOULD LIMIT THE NORTHERN EXTENT OF THE CONVECTION...AND
ONLY THE SOUTHERN HALF OF WESTERN AND CENTRAL NORTH DAKOTA SHOULD
HAVE CHANCES OF SHOWERS/THUNDER.
LIMITED CAPE THIS EVENING AND OVERNIGHT...BUT CAPE INCREASES ON
SUNDAY. THEREFORE ISOLATED THUNDERSTORMS EXPECTED WITH SHOWERS
TONIGHT...WITH CHANCES OF SHOWERS AND THUNDERSTORMS SUNDAY. BEST
CHANCES ALONG THE SOUTHERN TIER OF COUNTIES.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 238 PM CDT SAT AUG 8 2015
THE LONG TERM LOOKS WARM AND MAINLY DRY...WITH SLIGHT CHANCES FOR
THUNDERSTORMS LATER NEXT WEEK.
THE MODELS ARE IN FAIRLY GOOD AGREEMENT ABOUT BUILDING IN A HIGH
AMPLITUDE RIDGE ACROSS THE MOUNTAIN WEST. THE RIDGE IS EXPECTED
TO START BUILDING IN SUNDAY ACROSS THE WESTERN ROCKIES. BOTH THE
GFS AND ECMWF HAVE THE RIDGE EVER SO SLOWLY PROPAGATING EASTWARD
THROUGH NEXT WEEK. SOME OF THE WARMEST AIR OF THE YEAR IS POSSIBLE
ACROSS WESTERN NORTH DAKOTA THIS WEEK. TEMPERATURES IN THE UPPER
90S SEEM LIKELY...WITH SOME 100S POSSIBLE. SEVERAL FAST MOVING
SHORTWAVE TROUGHS WILL LIKELY TRAVERSE THE RIDGE MID/LATE NEXT
WEEK. HOWEVER...TIMING OF INDIVIDUAL WAVES AND ASSOCIATED
PRECIPITATION IS DIFFICULT AT BEST THIS FAR OUT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1238 AM CDT SUN AUG 9 2015
THE MAIN HAZARD TO AVIATION WILL BE POSSIBLE MVFR CONDITIONS IN
CLOUDS AND RAIN ACROSS SOUTHWEST NORTH DAKOTA TONIGHT. OTHERWISE
CONDITIONS WILL REMAIN VFR.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SCHECK
SHORT TERM...JV
LONG TERM...AJ
AVIATION...SCHECK
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
401 AM EDT SUN AUG 9 2015
.SYNOPSIS... WEAK FLOW CONTINUES TODAY. LOW PRESSURE SYSTEM PASSES
NORTH MONDAY INTO MONDAY NIGHT. MID/UPPER LEVEL TROF AXIS CROSSES
TUESDAY. DRIER AIR WITH COOLER NIGHTS WEDNESDAY AND THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
ANOTHER EARLY MORNING WITH AREAS OF CLOUDS VERSUS VALLEY FOG IN THE
WEAK DOG DAY WIND FLOW. A FEW SHOWERS REDEVELOPED OVER THE CENTRAL
WV MOUNTAINS BETWEEN 06Z AND 08Z PROBABLY AIDED BY A WEAK MID LEVEL
VORT MAX INDICATED ON RAP SOLUTION. BY 10Z FIGURING ANY SURVIVING
SHOWER WOULD BE IN VIRGINIA.
LESS INSTABILITY INDICATED THIS AFTERNOON OVER THE MOUNTAIN COUNTIES
COMPARED TO SATURDAY...BUT WITH THE WEAK FLOW AND SOME WEAK E TO W
COMPONENT IN THE LOW LEVELS ON THE EASTERN SLOPES...WILL LEAVE MORE
CLOUDS AND THE 20/30 POPS FOR AFTERNOON AND EARLY EVENING CONVECTION.
STRONGER BUT WEAKENING 500 MB VORT MAXIMUMS STREAK SE FROM NRN IL
AND INDIANA TODAY. THIS SHOULD INCREASE HIGH CLOUDS IN SE OHIO THIS
AFTERNOON...AND MAY HOLD TEMP DOWN A DEGREE OR 2. WILL BE SLOWER
INCREASING POPS IN NE KY AND HTS VCNTY BUT WILL ACTUALLY BE A BIT
FASTER INCREASING POPS FURTHER TO THE NORTH THIS EVENING...IN SE
OHIO...THEN TOWARD THE MID OHIO VALLEY INCLUDING PKB.
00Z MODEL SOLUTIONS DROP WEAKENING 500 MB VORT MAXIMUMS SE THRU CWA
OVERNIGHT SUNDAY NIGHT. QUESTION IS HOW FAST TO INCREASE POPS
FURTHER E...IN RESPONSE TO THESE FEATURES. 00Z GFS SEEMS A BIT
GENEROUS ON LIGHT PCPN FURTHER EAST AND SOUTH OVERNIGHT. WILL HAVE
20 POPS REACHING EKN TO CRW LINE TOWARD DAWN...CHANCE POPS FURTHER
WEST.
WITH INCREASING LAYERED CLOUDS OVERNIGHT...KEPT TEMPS A BIT HIGHER IN
THE MID OHIO VALLEY. STILL THINK THE SRN WV INTO SW VA COAL FIELD
COUNTIES COULD SEE VALLEY FOG OVERNIGHT.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
MODELS IN DECENT AGREEMENT ON MOVEMENT OF SURFACE LOW ACROSS LAKES
ERIE AND ONTARIO THROUGH TUESDAY. THE ECMWF IS THE FASTEST...AND NAM
THE SLOWEST MOVING THE LOW NORTHEAST...WITH THE GFS IN THE MIDDLE.
WARM FRONT WILL LIFT ACROSS CWA MONDAY...AND HAVE LIKELY POPS.
MODELS HAVE TRENDED FARTHER NORTH WITH THE SURFACE LOW...AND NOW
SHOW THE BEST SHEAR REMAINING NORTH OF CWA FOR THE DAY MONDAY. WITH
CONVECTION STARTING EARLY...SOME QUESTION AS TO HOW ORGANIZED THINGS
CAN GET WITH LACK OF STRONG DIURNAL HEATING. PWAT VALUES OF 1.5 TO 2
INCHES WILL LEAD TO DOWNPOURS...BUT THE GROUND HAS DRIED OUT SO DO
NOT ENVISION WIDESPREAD WATER CONCERNS.
MODEL TIMING DIFFERENCES DO HAVE SOME IMPACT ON TIMING THE COLD
FRONT PASSAGE...FOR NOW TRENDED TOWARD THE SLOWER SIDE OF THE
ENVELOPE WITH THE FRONT CROSSING SE OHIO LATE MONDAY NIGHT AND
EXITING THE WV MOUNTAINS EARLY TUESDAY AFTERNOON.
MID AND UPPER LEVEL TROUGH FOLLOW THE COLD FRONT...SO LINGERED
SHOWERS AND CLOUDS INTO TUESDAY EVENING ACROSS THE WEST...AND INTO
TUESDAY NIGHT IN THE WV MOUNTAINOUS COUNTIES. MODELS SHOW UPPER
TROUGH CLOSING OFF ON WEDNESDAY OVER SOUTHERN QUEBEC. WITH NW FLOW
AND WRAPAROUND MOISTURE INCLUDED ISOLATED SHOWERS IN THE NE CWA
WEDNESDAY. MAY EVENTUALLY NEED TO EXPAND THESE WESTWARD...JUST
DEPENDS ON HOW QUICKLY LOW LEVELS DRY OUT.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
A FRESH AIRMASS WILL SETTLE IN FOR THE EXTENDED WITH MILD
COMFORTABLE DAYS AND COOL NIGHTS. SOME MODERATION OVER THE
WEEKEND.
&&
.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
ANOTHER 06Z TO 12Z TIME FRAME WITH CLOUDS AND A FEW LINGERING
MOUNTAIN SHOWERS WHILE VALLEY FOG FORMS WHERE CLOUDS BREAK UP.
NEAR 06Z...FOG HAS ALREADY FORMED S OF CRW IN DEEP SRN WV COAL
FIELD COUNTIES.
CONFIDENCE SET AT MEDIUM...MAINLY FOR HOW FOG VERSUS CLOUDS WILL REACT
THROUGH 13Z THIS MORNING.
WEAK WIND FLOW ALSO CONTINUES TODAY.
LIKE SATURDAY...MORE DAYTIME CU FIGURED OVER THE MOUNTAIN COUNTIES WITH
CEILINGS 2 TO 3 THSD FT...WHILE MOSTLY SCT CU OVER LOWLANDS AT 3 TO 5
THSD FT AGL. FEW MOUNTAIN SHOWERS OR THUNDERSTORMS 17Z SUNDAY
THROUGH 02Z MONDAY.
LAYERED CL0UDS AT 5 TO 10 THSD FT INCREASING IN OHIO VALLEY COUNTIES
FOR 00Z TO 06Z MONDAY...WITH POSSIBLE SHOWER INTO SOUTHEAST OHIO
AND VSBY NEAR 5 MILES.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z MONDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: CLOUD COVER/FOG VARIABILITY 06Z TO 13Z SUNDAY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE SUN 08/09/15
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EDT 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13
CRW CONSISTENCY H H M L L L L L H H H H
HTS CONSISTENCY H M M L L L L H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H M M L L L L L H H H H
PKB CONSISTENCY H H M M M M M H H H H H
CKB CONSISTENCY H M L L L L L L H H H H
AFTER 06Z MONDAY...
IFR POSSIBLE IN SHOWERS AND THUNDERSTORMS MONDAY AND MONDAY
NIGHT...THEN IN LINGERING LOW CEILINGS AND SHOWERS TUESDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/MZ
NEAR TERM...KTB
SHORT TERM...MZ
LONG TERM...30
AVIATION...KTB
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1137 PM CDT SAT AUG 8 2015
.AVIATION...
AN OUTFLOW BOUNDARY...OR POSSIBLY TWO...WILL MOVE THROUGH KPVW AND
KLBB EARLY THIS MORNING AND BRING A SHIFT IN WIND
DIRECTION...HOWEVER WIND SPEEDS ARE EXPECTED TO REMAIN AROUND 12
KTS OR LESS. THERE IS A REMOTE CHANCE THAT A WEAK T-STORM COULD
APPROACH EITHER TERMINAL BETWEEN ABOUT 06 AND 10 UTC...BUT
CONFIDENCE NOT SUFFICIENT TO INCLUDE IN THE TAF. OTHERWISE...VFR
CONDITIONS WITH SOUTHERLY WINDS ARE EXPECTED AT ALL TERMINALS
WITH PERHAPS A LOW THREAT OF T-STORMS FOR KLBB AND KPVW AGAIN
SUNDAY EVENING.
&&
.PREV DISCUSSION... /ISSUED 650 PM CDT SAT AUG 8 2015/
AVIATION...
THE MAIN AVIATION CONCERN IS THE POTENTIAL FOR ISOLATED HIGH-BASED
T-STORM ACTIVITY TO APPROACH KLBB AND KPVW FROM THE WEST THIS
EVENING. THE MAIN THREATS FROM THIS ACTIVITY WILL BE
STRONG...ERRATIC WIND GUSTS AND LIGHTNING. CONFIDENCE IS TOO LOW
AT THIS TIME TO INCLUDE A TEMPO GROUP IN THE TAFS. OTHERWISE...VFR
CONDITIONS ARE EXPECTED WITH PERHAPS A LOW THREAT OF T-STORMS
AGAIN VERY LATE IN THE FORECAST PERIOD.
PREV DISCUSSION... /ISSUED 625 PM CDT SAT AUG 8 2015/
UPDATE...
SCATTERED THUNDERSTORMS HAVE DEVELOPED ACROSS EAST-CENTRAL NEW
MEXICO AND APPEAR POISED TO AFFECT THE FAR SOUTHWEST TEXAS
PANHANDLE AND PERHAPS THE EXTREME NORTHWESTERN SOUTH PLAINS.
GIVEN THIS WE HAVE INCREASED POPS CONSIDERABLY FOR OUR FAR
NORTHWESTERN ZONES THIS EVENING. THE REMAINDER OF THE FORECAST
REMAINS IN GOOD SHAPE AND NO OTHER ADJUSTMENTS WERE MADE ATTM.
PREV DISCUSSION... /ISSUED 234 PM CDT SAT AUG 8 2015/
SHORT TERM...
BIGGEST CHANGE FROM EARLIER FORECASTS WAS TO EXPAND ISOLATED STORM
MENTION EASTWARD ACROSS MUCH OF THE CAPROCK THIS EVENING. EARLY
AFTERNOON ANALYSIS INDICATES A FAVORABLE COLLOCATION OF SURFACE
TROUGHING AND STEEP MID-LEVEL LAPSE RATES JUST WEST OF THE TX-NM
BORDER. SURFACE DEWPOINTS AREA WIDE ARE RUNNING 5-15 DEGS HIGHER
THAN THIS TIME YESTERDAY AND ARE YIELDING 1000-2000 J/KG OF MLCAPE
ACROSS THE SOUTH PLAINS. ALREADY NOTICING SOME CU BUILDING SOUTH OF
CVS AT 19Z AS DEEP MIXING THERE CATAPULTS PARCELS TO THEIR CCL
LEVELS. THIS THEME SHOULD EXPAND SOUTHWARD ALONG THE SURFACE TROUGH
WITH A FEW STORMS LIKELY TO BE DOTTING OUR WESTERN ZONES BY LATE
AFTERNOON. AS THESE PULSE-TYPE CELLS MOVE SLOWLY NORTHEAST...OUTFLOW
REGENERATION OF NEW STORMS SEEMS PLAUSIBLE THROUGH EARLY EVENING IN
LIGHT OF MEAGER CIN. HRRR HAS BEEN QUITE ADAMANT IN BLOSSOMING A
LARGER COVERAGE OF STORMS BEFORE SUNSET...BUT WITH NO DISCERNIBLE
BACKGROUND SUPPORT AVAILABLE IT SEEMS A SAFER BET TO KEEP PRECIP
MENTION ON THE ISOLATED SIDE. A DECENT NOCTURNAL LLJ MAY KEEP SOME
SEMBLANCE OF THESE EARLIER STORMS INTACT AFTER MIDNIGHT.
SUNDAY WILL SEE A TALL AND CLOSED ANTICYCLONE RETROGRADE TO CENTRAL
TEXAS COMPLETE WITH RISING HEIGHTS AND THICKNESSES LOCALLY. THIS
PROCESS WILL HELP REORIENT THE SURFACE TROUGH FROM N-S TO NE-SW
ACROSS THE WRN TX PANHANDLE INTO ERN NM. BEST STORM CHANCES SHOULD
PLAY OUT IN THE NRN PANHANDLE NEAR THE INTERSECTION OF THE TROUGH
AND A STALLING FRONT...BUT DEEP MIXING AND WEAK CAPE IN OUR NW
COUNTIES COULD SPUR A FEW LATE AFTERNOON STORMS. OTHERWISE...MAX
TEMPS LOOK TO SHAKE OUT A DEGREE OR TWO WARMER THAN TODAY.
LONG TERM...
UPPER LEVEL RIDGE IS EXPECTED TO BE CENTERED OVER EAST
TEXAS SUNDAY EVENING WHILST VIGOROUS UPPER LEVEL LOW SLIDES DOWN THE
COAST OF BRITISH COLUMBIA. THE STRENGTH OF THE RIDGE IS EXPECTED TO
BE SUFFICIENTLY STRONG TO HOLD THE LOW OFF THE PACIFIC NORTHWEST
COAST AT LEAST THROUGH 120 HOURS BEFORE IT EJECTS NEWRD INTO SRN
CANADA. TO OUR NORTH A SHORTWAVE PASSES EARLY MONDAY ACROSS THE
CENTRAL PLAINS FOLLOWED BY ANOTHER SURGE OF ENERGY ROTATING ABOUT
HUDSON BAY LOW EARLY TUESDAY BEFORE RIDGE BUILDS STRONGLY ALL THE
WAY UP TO NUNAVUT. AS THE HIGH SLOWLY RETROGRADES...FLOW WILL
BECOME MORE NORTHERLY TO NORTHEASTERLY WITH TIME AND THIS SHOULD
HELP COOL TEMPS A BIT IN THE LATTER EXTENDED.
BEST RAIN CHANCES DURING THE EXTENDED WILL EXIST FROM SUNDAY EVENING
INTO TUESDAY AS FRONTAL BOUNDARY SAGS INTO THE REGION. HIGHEST
POTENTIAL WILL EXIST NORTH AND WEST. TRENDS HAVE BEEN EDGING THE
BOUNDARY FURTHER SOUTH WITH EACH RUN AND THIS CERTAINLY FITS THE
PATTERN THIS SUMMER. THINGS LOOK TO DRY OUT ON WEDNESDAY WITH
PERHAPS A FEW SCT SHOWERS NEAR THE ESCARPMENT BUT OVERALL TRENDING
DRIER FOR THE REMAINDER OF THE EXTENDED.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 64 94 67 90 / 50 20 20 30
TULIA 66 95 68 92 / 20 0 20 30
PLAINVIEW 65 95 70 93 / 20 0 10 20
LEVELLAND 68 96 70 95 / 20 0 10 20
LUBBOCK 71 98 72 96 / 20 0 10 10
DENVER CITY 68 98 69 96 / 20 0 10 10
BROWNFIELD 68 98 70 96 / 20 0 10 10
CHILDRESS 73 102 75 99 / 0 0 10 20
SPUR 70 101 72 99 / 0 0 10 0
ASPERMONT 75 104 75 103 / 0 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
33/23/
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1259 AM EDT SUN AUG 9 2015
.SYNOPSIS...
WEAK HIGH PRESSURE WILL MOVE OVERHEAD SUNDAY. RAIN CHANCES WILL
INCREASE MONDAY INTO MONDAY NIGHT AS A COMPLEX FRONTAL SYSTEM
MOVES INTO THE REGION. A COLD FRONT WILL SWEEP ACROSS THE AREA
TUESDAY FOLLOWED BY HIGH PRESSURE THAT BRING ANOTHER ROUND OF
DRIER AND COOLER WEATHER FOR MID AND LATE WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 940 PM EDT SATURDAY...
PERSISTENT AREA OF SHOWERS CONTINUE TO IMPACT CENTRAL PART OF FCST
AREA FROM NEAR WV/VA BORDER INTO NEW RIVER VALLEY AND MAY REACH
TO NEAR BLUE RIDGE OF FAR SW VA BY 11PM BEFORE LIKELY DISSIPATING
BY AROUND MIDNIGHT. LATEST HRRR RUN ACTUALLY NOW HAS PRETTY GOOD
HANDLE ON CURRENT RADAR DEPICTION AND DOES SHOW STEADY
WEAKENING...EXCEPT FOR AROUND THE BLUE RIDGE OF FAR SW VA AND NW
NC WELL AFTER MIDNIGHT. HAVE ONCE AGAIN EXTENDED SOME SLIGHT CHC
POPS A LITTLE LATER INTO THE OVERNIGHT BUT STILL REMOVING
COMPLETELY BY 07Z AS STILL FEEL THAT WITH NEGLIBLE INSTABILITY BY
THAT TIME THAT NAM AND SOME OTHER HI RES MODELS ARE OVERDOING IT
PERHAPS DUE TO A WEAK S/WV IN NW FLOW COMING FROM OHIO VALLEY THAT
NOT SURE IS EVEN REALLY THERE. REDUCED SKY COVER ON THE SW AND SE
FRINGES BUT LEFT MOSTLY CLOUDY IN THE MIDDLE OVERNIGHT WITH THE
WEAK LOW LEVEL CONVERGENCE NEAR BLUE RIDGE. KEPT PATCHY FOG BUT A
FORMING A BIT LATER. OTHERWISE TEMPS OVERNIGHT LOOK GOOD SO NO
OTHER CHANGES.
PREV DISCUSSION AS OF 655 PM EDT SATURDAY...
ISOLATED SHOWERS CONTINUE TO SLOWLY DRIFT SOUTHEASTWARD ACROSS
ALLEGHENY HIGHLANDS INTO SOUTHERN SHENANDOAH VALLEY AND IN A FEW
OTHER SPOTS ACROSS SOUTHEAST WV AND MTNS OF SW VA AND FAR NW NC.
HAVE NOT OBSERVED ANY IN-CLOUD OR CLOUD-TO-GROUND LIGHTNING SO
FAR THIS AFT AND EARLY EVE. WHILE HI RES MODELS LIKE HRRR...AS
WELL AS 18Z NAM...TRY TO LINGER THESE UNTIL MIDNIGHT OR EVEN
BEYOND...DO NOT SEE SIGNIFICANT MECHANISM ONCE WE LOSE HEATING TO
KEEP THESE GOING...OTHER THAN SOME WEAK LOW-LEVEL CONVERGENCE NEAR
THE BLUE RIDGE WHICH MAY BE ENOUGH TO EXTEND A FEW MORE HOURS PAST
SUNSET BUT NOT ALL THAT CONFIDENT. INSTABILITY REMAINS QUITE LOW
AND CONFINED MAINLY TO THE WESTERN SLOPES SO AS THESE MOVE FARTHER
EAST THEY SHOULD SLOWLY DIE. NEVERTHELESS...HAVE STRETCHED THE
15-20 POP AREA JUST EAST OF THE BLUE RIDGE AND EXTENDED IN TIME
UNTIL ABOUT MIDNIGHT PER THESE MODELS...BUT NOT READY TO GO BEYOND
THAT YET. OTHERWISE OTHER THAN A FEW NUDGES TO TEMPS, DEW PTS AND
SKY COVER PER LATEST OBSERVATIONS...NOT OTHER CHANGES THROUGH THE
OVERNIGHT.
PREV DISCUSSION AS OF 222 PM EDT SATURDAY...
LOCAL WRF/HRRR ISOLATED TO WIDELY SCATTERED SHOWERS FROM THE
ALLEGHANY HIGHLANDS WV/VA SOUTHWARD TO THE VA FOOTHILLS THROUGH
EARLY EVENING BEFORE DISSIPATING. MAY SEE A FEW SHOWER SOUTHWEST
TOWARD THE MTNS OF NC/FAR SW VA AS WELL CLOSER TO HIGHER THETA-E
AIR. STILL NOT MUCH OUT THERE...AND EVEN THREAT OF THUNDERSTORMS IS
LOW WITH MARGINAL CAPE.
OVERNIGHT HAVE INCREASED CLOUD COVER AS THINK WE WILL SEE AN
INVERSION SET UP WITH LITTLE TO NIL MIXING AND ANY LINGERING
STRATOCU/CU WILL SPREAD OUT THROUGH THE NIGHT. NOT COMPLETELY CLOUDY
SO NOT OUT OF THE QUESTION TO SEE FOG FORM IN THE VALLEYS OVERNIGHT.
LOWS WILL STAY CLOSE TO SEASONAL NORMS OF LOW TO MID 60S.
SUNDAY...THE 5H RIDGE AND HEIGHTS BUILD A LITTLE TO THE NORTHEAST.
WEAK UPPER SUPPORT TO COMBINE WITH LOW LEVEL THETA-E RIDGE OVER THE
BLUE RIDGE TO FORM A FEW SHOWERS/ISOLATED STORMS IN THE AFTERNOON.
SKIES WILL BE MOSTLY SUNNY OVER THE PIEDMONT...TO PARTLY
SUNNY...BECOMING MOSTLY CLOUDY WEST. HIGHS TO RANGE FROM THE UPPER
70S TO LOWER 80S IN THE MOUNTAINS...TO MID TO UPPER 80S EAST.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY/...
AS OF 330 PM SATURDAY...
SIMILAR TO PAST FEW EVENINGS...ONGOING SHOWERS AND THUNDERSTORMS
SUNDAY WILL DIMINISH BEFORE MIDNIGHT.
FORCING WILL BE A COMBINATION OF WARM AIR ADVECTION AND OVERRUNNING
ACROSS THE WARM FRONT AND LIFT AHEAD OF THE COLD FRONT MONDAY NIGHT
AND TUESDAY MORNING. THE MOST UNSTABLE AIR WILL BE JUST ALONG THE
FRONT SO STRONG THUNDERSTORMS ARE STILL POSSIBLE IN THE EASTERN
COUNTY WARNING AREA TUESDAY AFTERNOON BUT THIS IS HEAVILY DEPENDENT
ON THE SPEED OF THE FRONT. DEEP MOISTURE WITH PRECIPITABLE WATER
VALUES JUST UNDER 2.0 INCHES WILL FILL IN ACROSS THE FORECAST AREA
ON SUNDAY NIGHT.
USED WARMER GUIDANCE FOR MINIMUM TEMPERATURES ON SUNDAY NIGHT SINCE
DEW POINTS WILL BE INCREASING. CLOUDS AND PRECIPITATION WILL LIMIT
TEMPERATURE RISE ON MONDAY. HAVE TRIMMED BACK MAXIMUM TEMPERATURES.
FORECAST AREA WILL STILL BE AHEAD OF THE COLD FRONT ON MONDAY NIGHT
SO TEMPERATURES WILL REMAIN MILD. MAV GUIDANCE LOOKS REASONABLE FOR
MONDAY NIGHT LOWS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 200 PM SATURDAY...
CLOSED 500 MB LOW OVER SOUTHEAST CANADA BY TUESDAY NIGHT AND A DEEP
TROF REMAINS OVER THE EAST THROUGH THURSDAY. BY FRIDAY THERE IS
STILL TROUGHING OVER THE EASTERN UNITED STATES BUT THE UPPER LOW HAS
RETREATED NORTH AND HEIGHTS ARE HIGHER OVER THE MID ATLANTIC STATES.
THERE MAY BE ENOUGH VORTICITY ROTATING AROUND THE UPPER LOW ON
WEDNESDAY TO PROVIDE SOME LIFT TO THE MOUNTAINS IN SOUTHEAST WEST
VIRGINIA.
SURFACE HIGH PRESSURE OVER THE MISSISSIPPI VALLEY ON TUESDAY NIGHT
WILL GRADUALLY BUILD EAST. BY FRIDAY MORNING AT LEAST A PIECE OF THE
HIGH WILL BE CENTERED OVER THE FORECAST AREA. THE HIGH STAYS IN THE
REGION THROUGH THE WEEKEND.
ECMWF HAS BEEN PERSISTENT LAST FEW DAYS BRINGING COOLER AND DRIER
AIR MASS INTO THE FORECAST AREA WITH 850 MB TEMPERATURES IN +10 TO
+12 RANGE BY THURSDAY MORNING. THEN AIR MASS MODERATES ON FRIDAY AND
SATURDAY WITH NEAR NORMAL TEMPERATURES.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 1240 AM EDT SUNDAY...
PERSISTENT SHOWERS CONTINUE TO MEANDER ALONG A CORRIDOR FROM KLWB
SOUTH TO KPSK/KHLX TONIGHT WHERE LOW LEVEL MOISTURE CONVERGENCE
REMAINS UNDER THETA-E RIDGING AND SUPPORTED BY LOW LEVEL EASTERLY
FLOW. EXPECT THESE SHOWERS TO DRIFT SOUTH AND FINALLY FADE BY
DAYBREAK BUT STILL MAY NEED TO KEEP A VFR PREVAILING GROUP OR VCSH IN
AT KLWB A WHILE LONGER.
OTRW STRATOCUMULUS CLOUD COVER CONTINUES TO ALSO FILL IN UNDER
THE STRONG MID LEVEL INVERSION AND EXPECT ANOTHER WIDESPREAD
CANOPY BY DAYBREAK. HOWEVER STILL APPEARS THAT MOST SPOTS EAST OF
THE BLUE RIDGE WILL STAY WITH MAINLY LOW END VFR CIGS WHILE MVFR
TO IFR LIKELY OVER THE WEST ESPCLY WHERE RAIN HAS OCCURRED. PATCHY
MIST WILL REDUCE VISIBILITIES TO MVFR OR BRIEF IFR LEVELS MAINLY
WITHIN SOME THE MOUNTAIN AND RIVER VALLEYS.
ANY SUB-VFR CONDITIONS ARE EXPECTED TO IMPROVE TO VFR BY
15-16Z/11AM-NOON ON SUNDAY. ADDITIONAL ISOLATED TO SCATTERED
AFTERNOON SHOWERS ARE EXPECTED ON SUNDAY...ESPECIALLY ACROSS THE
MOUNTAINS BUT AGAIN TOO LOCALIZED TO INCLUDE MENTION IN THE TAFS
FOR NOW. HOWEVER WITH A SIMILAR SETUP TO TONIGHT...MAY SEE
ADDITIONAL SHOWERS LINGER IN SPOTS THROUGH SUNDAY NIGHT WITH
MOSTLY VFR CIGS EXCEPT MVFR OR WORSE NEAR ANY SHRA ESPCLY DURING
THE EVENING.
EXTENDED AVIATION DISCUSSION...
AS OF 125 PM EDT SATURDAY...
MONDAY INTO TUESDAY...SHOWERS AND STORMS INCREASE AGAIN ACROSS THE
REGION THANKS TO BOTH A FRONTAL BOUNDARY ENTERING THE REGION AND A
SHORTWAVE TROUGH PROGRESSING EASTWARD THROUGH THE OHIO VALLEY.
MAINLY VFR CONDITIONS ARE EXPECTED EXCEPT SUB-VFR CONDITIONS
WHERE CONVECTION BECOMES MORE ORGANIZED. FOR NOW APPEARS THE BEST
CHANCE AT SEEING MORE WIDESPREAD POOR FLYING CONDITIONS WILL COME
LATER MONDAY INTO MONDAY EVENING AS AN AXIS OF DEEPER MOISTURE
PIVOTS ACROSS.
BY WEDNESDAY INTO THURSDAY...ANOTHER AREA OF HIGH PRESSURE BUILDS
INTO THE REGION MAKING FOR OVERALL VFR CONDITIONS. PATCHY LATE
NIGHT AND EARLY MORNING MOUNTAIN AND RIVER VALLEY FOG WILL AGAIN
BE POSSIBLE...THOUGH AIRMASS WILL BE DRIER.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...DS/JH/WP
NEAR TERM...SK/WP
SHORT TERM...AMS
LONG TERM...AMS
AVIATION...DS/JH/WP
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1018 AM CDT SUN AUG 9 2015
.UPDATE...
959 AM CDT
THE CONVECTIVE COMPLEX OVERHEAD IS QUICKLY WARMING ALOFT THIS
MORNING WITH THE SYSTEM CONTINUING TO REFOCUS OVER CENTRAL IL.
RAIN HAS STRUGGLED TO SPREAD NORTH OF A ROCHELLE TO JOLIET TO DE
MOTTE INDIANA LINE THIS MORNING DESPITE A SURGING GRAVITY WAVE
ESQ BOUNDARY SHIFTING NORTHEAST EARLIER THIS MORNING. THE
BOUNDARY HAS WEAKENED CONSIDERABLY AND AREAS ALONG THE
AFOREMENTIONED LINE ARE JUST NOW POSSIBLY SEEING SOME SPRINKLES.
IN GENERAL THE RAIN WILL GRADUALLY WEAKEN AS IT SHIFTS EAST WITH
THE MAJORITY OF RAIN FALLING SOUTH OF A MENDOTA TO JOLIET TO DE
MOTTE INDIANA LINE. FAR NORTHEAST IL INCLUDING THE CHICAGO METRO
MAY SEE SOME SPRINKLES TO A LIGHT RAIN SHOWER CLOSER TO NOON...BUT
NOTHING OVERLY SIGNIFICANT. ISOLATED EMBEDDED THUNDERSTORMS ARE
ALSO POSSIBLE SOUTH OF THE MENDOTA...JOLIET...DE MOTTE LINE
THROUGH THE MORNING BUT NO SEVERE WEATHER IS EXPECTED.
GUIDANCE IS REALLY STRUGGLING WITH THE CONVECTIVE EVOLUTION GOING
INTO THIS AFTERNOON WITH THE RAP AND HRRR LOOKING THE MOST
REASONABLE THUS FAR. MADE MINOR TWEAKS TO PRECIP CHANCES THROUGH
THIS AFTN WITH THE FOCUS FOR EITHER FESTERING RAIN AND STORMS OR
SOME REDEVELOPMENT ALONG AND SOUTH OF I-80. KEPT A CHANCE OF
SHOWERS AND STORMS ACROSS THE CWA THIS AFTERNOON AS CONFIDENCE IS
LOW AS TO HOW FAR NORTH ACTIVITY WILL CONTINUE TO FESTER. WITH THE
MCV OVER CENTRAL IL...HAVE MUCH HIGHER CONFIDENCE IN AREAS SOUTH
OF I-80 SEEING THE MAJORITY OF ACTIVITY. DEBATED GOING DRY NORTH
OF I-88 THIS AFTN...BUT CANNOT RULE OUT A FEW SHOWERS AND PERHAPS
A STORM.
AS FAR AS STRONG TO SEVERE STORMS...CANNOT RULE OUT ONE OR TWO
STRONG STORMS...BUT THINKING WE WILL STRUGGLE TO RECOVER THIS AFTN
GIVEN THE THICK CLOUD COVER AND LINGERING RAIN. AGREE WITH THE
MARGINAL RISK FROM SPC. THINKING THE AREA OF CONCERN WOULD BE
SOUTH OF A STREATOR TO DE MOTTE LINE WITH THE BEST ACTIVITY WELL
SOUTH OF THE CWA OVER CENTRAL IL MUCH CLOSER TO THE MCV.
JEE
&&
.SHORT TERM...
358 AM CDT
THROUGH SUNDAY NIGHT...
TWO COMPLEXES OF SHOWERS AND THUNDERSTORMS ARE ONGOING EARLY THIS
MORNING THOUGH HAVE GENERALLY BEEN MERGING INTO ONE TO SOME
DEGREE...THOUGH STILL LOOK TO BE DISTINCT BASED ON THE LIGHTNING
AXES IN CENTRAL IOWA EXTENDING INTO WESTERN ILLINOIS..AND A
SEPARATE AREA IN SOUTHERN IOWA INTO NORTHERN MISSOURI.
AT THE MOMENT...THE NORTHERN EXTENT OF THE NORTHERN BATCH ENTERING
NW ILLINOIS IS IN A LESS HOSPITABLE ENVIRONMENT FOR CONTINUED FORWARD
PROPAGATION AND GROWTH AND BEING DRIVEN MORE SO FROM AN UPPER
LEVEL SHORTWAVE RIDING THE NORTHERN FRINGE OF THE RIDGE AXIS. THE
DEPTH OF THESE SHOWERS IS NOT IMPRESSIVE...AND EROSION ON THIS
ACTIVITY CONTINUES WITH JUST SOME LIGHT RAIN/SPRINKLES...WITH THE BEST
CHANCE FOR EROSION TO CONTINUE WILL BE IN NORTHERN ILLINOIS WITH
THE DRIEST AIRMASS AND MOST REMOVED FROM THE MAIN LOWER LEVEL
FORCING/BAROCLINIC ZONE. THE LLJ IS FOCUSED MORE-SO INTO THE
SOUTHERN MOST STORMS WHICH HAVE THE UPPER ENERGY SUPPORT COMBINED
WITH A BETTER THERMODYNAMIC ENVIRONMENT. LASALLE/LIVINGSTON/LEE
COUNTIES OR ON THE EASTERN EXTENT OF THE BETTER LLJ FORCING WHERE
MORE ORGANIZED AND SUSTAINED DEVELOPMENT WILL CONTINUE IN THE
COMING HOURS. MORE ROBUST DEVELOPMENT IS OCCURRING ON THE BACK
SIDE OF THIS COMPLEX WHERE A PORTION OF THE STRONGER LLJ WHICH
FEEDING THE SOUTHERN SYSTEM IS ABLE TO ADVECT NORTH INTO THE
NORTHERN STREAM ACTIVITY.
WITH THIS COMPLEX SETUP AT THE MOMENT...CONFIDENCE ON THE EVOLUTION
IS NOT AS HIGH AS I WOULD LIKE IT TO BE WITH MODELS STRUGGLING WITH
INITIALIZATIONS. THERE IS LITTLE TO SUGGEST THAT THESE SHOWERS AND
STORMS WON`T CONTINUE EASTWARD ONCE THE SHORTWAVE DRIVING IT
MOVES RIGHT ON THROUGH NE ILLINOIS...BUT DO PREFER THE HRRR
SOLUTION WHICH JUST BRINGS SOME LIGHTER RAIN NORTH (AND POSSIBLY
DRY IN FAR NORTH/NE ILLINOIS) AND FOCUSES ACTIVITY SOUTH THIS
MORNING. THE LLJ WHICH IS STILL STRONGEST IA BASED ON AREA VWPS
WILL BECOME ORIENTED SW-NE WITH THE MOISTURE CONVERGENCE AXIS
POINTED RIGHT AT US. THE INSTABILITY AXIS LOOKS TO BE POSITIONED
ACROSS THE CENTER OF THE CWA WHICH WILL LIKELY KEEP THE NORTHERN
AREAS JUST RAIN...WHEREAS POINTS SOUTH WILL AT LEAST SEE EMBEDDED
THUNDER DESPITE MARGINAL MID LEVEL LAPSE RATES. PRECIPITABLE WATER
VALUES ARE QUITE AN UPTICK THIS MORNING...SO THE I-80 SOUTHWARD
CORRIDOR MAY SEE SOME 1" PER HOUR RATES IN AN EFFICIENT
ENVIRONMENT.
SOME UNCERTAINTIES ON REMAINING FORCING IN THE AFTERNOON...AND
POTENTIAL FOR MORNING ACTIVITY TO KEEP ANY OUTFLOW FOCUSED SOUTH
OF THE AREA. THE LOCATION OF THE SURFACE FRONT MAY BECOME A BIT
MORE UNCERTAIN AFTER THESE STORMS LAY OUT ANY OUTFLOW. THE AIR
MASS WILL BE MOIST...THERE WILL BE SOME SHEAR AROUND...AND A LOW
LEVEL BOUNDARY...WHICH PRESENTS SOME CONCERNS WITH ANY ADDITIONAL
SUBTLE SHORTWAVES THAT MAY PASS THROUGH IN PROGRESSIVE WESTERLY
FLOW. HI-RES GUIDANCE IS RE-GENERATING STORMS IN IOWA THIS
AFTERNOON...AND DEPENDING ON WHERE THE SURFACE BOUNDARY ENDS UP
COULD POSE A MARGINAL SVR THREAT AS OUTLINED IN THE DAY 1 OUTLOOK
AND WILL NEED TO BE IRONED OUT BY THE DAY SHIFT.
AFTER WHAT COULD BE AN AFTERNOON LULL..THE SURFACE LOW TO OUR SOUTH
LIFTS NORTHEASTWARD SUNDAY NIGHT INTO EARLY MONDAY. ANOTHER
SHORTWAVE APPROACHES WITH THE INVERTED TROUGH AXIS POINTED RIGHT
OVER NORTHEAST ILLINOIS TONIGHT FOR POTENTIALLY A REINVIGORATION OF
SHOWERS...BUT STILL SOME UNCERTAINTY ON COVERAGE AT THIS POINT.
KMD
&&
.LONG TERM...
ONE LAST HOORAH AS THE UPPER LOW IN THE CANADIAN PRAIRIES LIFTS
TOWARD HUDSON BAY...OPENING THE DOOR FOR ONE LAST SHORTWAVE IN
NORTHWEST FLOW ALOFT TO MOVE THROUGH WISCONSIN COUPLED WITH
ADDITIONAL FAST MOVING WAVES COMING FROM THE PACIFIC. SLIGHTLY
BETTER LAPSE RATES ALOFT COUPLED WITH A SOUTHWARD MOVING COLD FRONT
WOULD SUGGEST THE POTENTIAL FOR SOME SCATTERED SHOWERS AND
THUNDERSTORMS MONDAY AFTERNOON/EARLY EVENING. SCATTERED MENTION DUE
TO THE TIMING/MOISTURE ISSUES AND THE FACT THE BETTER FORCING SWINGS
BY TO THE NORTH.
THE STRONG UPPER DISTURBANCE SOUTH OF HUDSON BAY WILL MOVE SOUTHEAST
ON MONDAY NIGHT INTO TUESDAY AND HIGH PRESSURE BUILDS IN FOR SEVERAL
DAYS. A HIGHLY AMPLIFIED PATTERN WILL SLOW THE PROGRESSION OF
SHORTWAVE ACTIVITY. WE WILL LARGELY BE UNDER THE INFLUENCE OF A
COMBINATION OF THE WESTERN U.S. RIDGE SUPPLYING THE DRY WEATHER AND
THE COOLING INFLUENCE OF NORTHWEST FLOW ON THE BACK SIDE OF THE
EASTERN U.S TROUGH. HIGHS WILL BE SLIGHTLY BELOW NORMAL WITH
COMFORTABLE HUMIDITY AND DECENT SUNSHINE. MOISTURE RETURN IS LACKING
UNTIL LATER IN THE WEEK WHEN A FRONTAL BOUNDARY DROPS THROUGH
THURSDAY NIGHT INTO FRIDAY. THIS WILL BE OUR NEXT CHANCE FOR SHOWERS
AND THUNDERSTORMS.
KMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* FOG WITH MVFR VIS THIS MORNING.
* WINDS VARIABLE TURNING EAST AT 7-9KT THIS AFTERNOON.
* SHOWERS THIS AFTERNOON INTO THE EVENING.
* FOG AND LOW CEILINGS TONIGHT...LOW END MVFR CEILINGS WITH IFR
POSSIBLE.
MM
//DISCUSSION...UPDATED 12Z...
LATEST RADAR IMAGERY DEPICTING PRECIP SHIELD STILL SLOWLY MOVING
EAST ACROSS NORTHERN ILLINOIS...WITH ITS EASTERN EXTENT STILL
ERODING AT THIS TIME. MOST GUIDANCE INCLUDING SHORT TERM...NOT
QUITE HANDLING EVOLUTION OF THIS PRECIP TOO WELL THIS
MORNING...BUT STILL THINKING PRECIP WILL REACH THE TERMINALS LATER
TODAY. PERSISTENT FORCING WILL CONTINUE THROUGH MIDDAY AND WHILE
THE COLUMN SATURATES...SHOULD BEGIN TO SEE PRECIP REACHING THE
TERMINALS BY LATE MORNING/MIDDAY. HOWEVER...COVERAGE MAY BE MORE
SCATTERED DURING THIS TIME. CONFIDENCE IS HIGHER THAT ANY THUNDER
TODAY WILL BE WELL SOUTH OF THE TERMINALS...AND HAVE CONTINUED TO
EXCLUDE FROM TAFS. WITH THIS SLOW MOVING SYSTEM ITS POSSIBLE AT
LEAST ISOLATED TO WIDELY SCATTERED SHOWERS MAY LINGER ACROSS THE
TERMINALS THROUGH THIS EVENING...BEFORE DEPARTING TO THE EAST. VFR
CONDITIONS TODAY WILL EVENTUALLY LOWER AND SLOWED THIS TREND THAN
WHAT GUIDANCE IS INDICATING...THINKING THE LOWER CEILINGS WONT
ARRIVE UNTIL LATER THIS EVENING WHEN SURFACE LOW/TROUGH MOVES
OVERHEAD. HAVE LOW END MVFR CEILINGS BUT DO THINK IFR WILL
EVENTUALLY BE POSSIBLE. DONT HAVE A GOOD FEEL WITH TIMING OF THIS
POSSIBLE IFR...AND SO HAVE LEFT OUT AT THIS TIME.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH WITH FOG/VIS THIS MORNING.
* HIGH WITH EASTERLY WIND DIRECTION...MEDIUM THAT SPEEDS STAY
BELOW 10KT.
* MEDIUM-LOW CONFIDENCE WITH SHOWERS THIS AFTERNOON/EVENING.
* HIGH CONFIDENCE WITH FOG AND LOW CEILINGS OCCURRING
TONIGHT...MEDIUM LOW WITH LOWEST HEIGHT AND TIMING/DURATION.
MM
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...SLIGHT CHANCE OF THUNDERSTORMS EARLY.
TUESDAY...VFR.
WEDNESDAY...VFR.
THURSDAY...VFR.
FRIDAY...CHANCE OF THUNDERSTORMS.
SATURDAY...VFR.
RODRIGUEZ
&&
.MARINE...
230 AM CDT
HIGHLY VARIABLE WIND FIELD ACROSS THE LAKE THIS MORNING AS A
WEAKER SURFACE PATTERN IN PLACE...WITH HIGH PRESSURE SITUATED TO
THE EAST AND NORTHEAST. THESE VARIABLE WINDS WILL LIKELY PERSIST
ACROSS THE NORTHERN HALF OF THE LAKE TODAY WHILE THE SOUTHERN END
BECOMES MORE SOUTHERLY THIS MORNING...AS LOW PRESSURE SLOWLY MOVES
EAST TOWARDS THE REGION. AS THIS THIS LOW CONTINUES EAST NORTHEAST
TO THE SOUTHERN END OF THE LAKE AND A SEPARATE LOW OVER ONTARIO
MOVES EAST TO HUDSON BAY TONIGHT...WINDS WILL LIKELY CONTINUE TO
BE VARIABLE ACROSS THE LAKE. HOWEVER...IT DOES APPEAR THAT SPEEDS
WILL STAY ON THE LIGHTER SIDE THROUGH THIS PERIOD. THIS LOW WILL
THEN MOVE TO THE EASTERN LAKES MONDAY INTO MONDAY NIGHT AS HIGH
PRESSURE TO THE NORTHWEST BEGINS SPREADING SOUTHEAST...WITH
NORTHERLY WINDS SETTING UP ACROSS THE ENTIRE LAKE. AS THE SURFACE
GRADIENT TIGHTENS UP OVER THE LAKE LATE MONDAY AND MONDAY
NIGHT...NORTHERLY SPEEDS WILL BEGIN TO INCREASE. THIS INCREASING
TREND WITH THE NORTHERLY WINDS CONTINUES TUESDAY WITH 15 TO 25 KT
WINDS BECOMING LIKELY DURING THIS TIME.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS DODGE CITY KS
604 AM CDT SUN AUG 9 2015
...Updated aviation discussion...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 330 AM CDT SUN AUG 9 2015
Upper level ridging will migrate westward from the southern
plains into the southern and central Rockies through mid week. A
shortwave trough will progress across the northern plains over the
upper level ridge today and tonight, helping to push a cold front
through the remainder of southwestern Kansas. There will be a
good chance of thunderstorms as the cold front passes, with the
best chances being this afternoon and evening ahead of the front
or south of a line from Liberal to Bucklin to Stafford where
temperatures will warm into the 90s. Marginally severe hail and
wind gusts to 60 mph are possible with these storms. However,
despite the slightly cooler temperatures north of the front, low
level moisture will be very rich with dewpoints near 70F.
Therefore, surface based CAPE values will be even higher in this
area. The greatest shear will also be north of the front given
the stronger upper level winds and easterly low level winds. Thus,
storms that develop from Garden City to Dodge City northeastward
to Ness City, Jetmore and Rush Center this afternoon will be
capable of large hail.
.LONG TERM...(Monday THROUGH Saturday)
ISSUED AT 330 AM CDT SUN AUG 9 2015
Thunderstorms will end late Sunday night in south central Kansas.
Surface high pressure will edge into western Kansas Monday with
north winds. Thunderstorm activity will likely be suppressed into
the southern plains on Monday. By Monday night into Wednesday,
there will be chances for thunderstorms from Dodge City west to
the Colorado state line despite the proximity of upper level
ridging since post frontal, moist upslope flow is expected to
persist for several days. The beat chance for thunderstorms will
be over far southwest Kansas where the best moisture and upslope
flow will be, with western high plains convection moving into
this area. Severe weather is unlikely through this week as the
mid to upper level winds will be very weak; but localized heavy
rain is a possibility in far western Kansas. Temperatures will be
cooler with highs mainly in the upper 80s Monday, mid 80s Tuesday
and Wednesday and upper 80s on Thursday and Friday. Drier weather
is likely starting Thursday as the upper level ridge becomes even
more amplified, with a less favorable northerly mid level flow
regime across the high plains. Temperatures should warm into the
lower 90s by the weekend.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z Monday MORNING)
ISSUED AT 602 AM CDT SUN AUG 9 2015
BUFR soundings, RAP and HRRR indicating VFR conditions can be
expected today at all three taf sites. There will be a chance for
some scattered thunderstorms later today, especially in the DDC
area. At this time the probability of these storm impacting either
GCK or HYS is low so am leaning towards not inserting a mention of
thunderstorms into these taf sites just yet. May insert a prob30
at GCK. At DDC will include a tempo group of -TSRA in the tafs
between 21z Sunday and 00z Monday based on location of the surface
boundary and late day instability. The prevailing wind today will
be northeast at 10 knots or less.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 91 69 89 66 / 50 40 10 20
GCK 89 68 86 66 / 30 20 10 30
EHA 92 67 86 66 / 40 30 30 50
LBL 93 70 89 68 / 50 40 20 40
HYS 90 69 87 65 / 30 30 10 10
P28 98 73 91 70 / 40 60 20 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Finch
LONG TERM...Finch
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
855 AM EDT SUN AUG 9 2015
...FORECAST UPDATE...
ISSUED AT 855 AM EDT SUN AUG 9 2015
HAVE A NEW NORTH/SOUTH ORIENTED BAND OF STORMS FORMING OVER
SOUTHWEST ILLINOIS THIS HOUR. THE HRRR FROM 08-09Z HAD THIS
BAND...BUT THE LATEST RUN DOES NOT. THE EARLIER RUNS SHOWED THIS
BAND DISSIPATING BEFORE IT GETS INTO OUR REGION...BUT DOES SHOW A
CHANCE IN THE MID TO LATE AFTERNOON HOURS FOR SOME LIGHT RAINS WITH
PERHAPS A RUMBLE OF THUNDER OVER OUR NORTHERN FORECAST HOUR. STILL
LOOKING LIKE A SWATH OF STORMS WILL MOVE ACROSS SOME PARTS OF THE
REGION OVERNIGHT. MADE SOME SLIGHT TWEAKS TO THE EVENING FORECAST
POPS...AS WELL AS BLENDED CURRENT OBS INTO THE ONGOING FORECAST.
.SHORT TERM (NOW THROUGH MONDAY)...
ISSUED AT 330 AM EDT SUN AUG 9 2015
IN THE NEAR TERM, CLEAR TO PARTLY CLOUDY SKIES WERE NOTED ACROSS THE
FORECAST AREA. EARLY MORNING TEMPERATURES WERE IN THE MID-UPPER
60S. SOME PATCHY FOG WAS DEVELOPING ACROSS THE TYPICAL FOG PRONE
AREAS. CLEAR TO PARTLY CLOUDY SKIES WILL CONTINUE FOR THE REMAINDER
OF THE NIGHT WITH LOW TEMPERATURES HITTING THEIR MINIMUMS TOWARD
DAWN.
FOR TODAY, THE OHIO VALLEY WILL SEE ONE MORE DAY UNDER THE INFLUENCE
OF AN UPPER LEVEL RIDGE. WE`RE ON THE NORTHEASTERN PERIPHERY OF THE
RIDGE AXIS AND THIS RIDGE IS FORECAST TO RETROGRADE WESTWARD THROUGH
THE PERIOD. AS THIS OCCURS, WE`LL SEE OUR FLOW PATTERN REVERT BACK
TO A NORTHWESTERLY FLOW. WITHIN THIS NORTHWESTERLY FLOW, A SERIES
OF MID-LEVEL WAVES ROTATING AROUND THE EDGE OF THE RIDGE WILL ROLL
THROUGH THE REGION. CLOUDS WILL BE ON THE INCREASE TODAY WITH HIGH
CIRRUS ROLLING INTO THE REGION. AFTERNOON HIGHS SHOULD BE SLIGHTLY
WARMER THAN WHAT WE SAW SATURDAY AFTERNOON WITH MID-UPPER 80S ACROSS
THE REGION.
FOR TONIGHT, THE FIRST IN A SERIES OF WAVES WILL PUSH INTO THE
REGION LATE. THIS FEATURE SHOULD SPAWN AN MCS TO OUR NORTHWEST
WHICH SHOULD THEN DIVE EAST-SOUTHEAST. BY THE TIME IT REACHES OUR
AREA EARLY MONDAY MORNING, IT IS FORECAST TO BE IN A WEAKENING
PHASE. NONETHELESS, WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY
LOOKS LIKELY LATE TONIGHT AND INTO MONDAY MORNING. THEREFORE, WILL
CONTINUE HIGH POPS FOR LATE TONIGHT. TEMPERATURES LOOK TO REMAIN
MILD WITH LOWS IN THE UPPER 60S TO THE LOWER 70S.
FOR MONDAY, SOMEWHAT OF A MORE COMPLEX FORECAST HERE AS WIDESPREAD
CONVECTION IN THE MORNING HOURS WILL LIKELY RESULT IN MORE LIMITED
INSTABILITY AS A FRONT PUSHES IN FROM THE NORTHWEST. MID-LEVEL FLOW
STILL LOOKS TO BE DECENT WITH 30-35 KT MID-LEVEL FLOW OVERSPREADING
THE REGION. HOWEVER, QUESTION REMAINS HOW MUCH CLOUD COVER WILL
LIMIT INSTABILITY. BASED ON THERMODYNAMIC AND KINEMATIC PROFILES,
MULTI-CELLULAR CONVECTION SEEMS TO BE THE PRIMARY CONVECTIVE MODE ON
MONDAY WITH GUSTY WINDS BEING THE MAIN THREAT WITH A LOWER LEVEL
THREAT OF MARGINALLY SEVERE HAIL. CLOUDS AND PRECIPITATION WILL
LIKELY HOLD TEMPERATURES DOWN WITH READINGS GENERALLY IN THE MIDDLE
80S. IF CURRENT MODEL TRENDS CONTINUE, SOME DOWNWARD ADJUSTMENT IN
MAX TEMPS MONDAY MAY BE REQUIRED IN SUBSEQUENT FORECASTS.
.LONG TERM (MONDAY NIGHT THROUGH SATURDAY)...
ISSUED AT 300 AM EDT SUN AUG 9 2015
AT THE START OF THE EXTENDED PERIOD MONDAY NIGHT, A SURFACE COLD
FRONT WILL PUSH THROUGH SOUTH-CENTRAL INDIANA AND CENTRAL KENTUCKY
AS A MID-LEVEL TROUGH DIGS ACROSS THE GREAT LAKES STATES. WHILE MUCH
OF THE DEEP-LAYERED MOISTURE WILL HAVE PUSHED TO OUR EAST, RESIDUAL
LOW-LEVEL MOISTURE AND INSTABILITY COMBINED WITH MODEST FRONTAL
CONVERGENCE SHOULD BE ENOUGH TO FORCE ISOLATED/SCATTERED CONVECTION
ALONG/AHEAD OF THE FRONT MONDAY EVENING, BEFORE WEAKENING OVERNIGHT.
THEREAFTER, THE EXTENDED PERIOD WILL BE CHARACTERIZED BY A MID-LEVEL
AVERAGE TROUGH POSITION ALONG THE EAST COAST, AND A PERSISTENT RIDGE
FROM THE SOUTHWEST U.S. NORTHWARD INTO THE NORTHERN HIGH PLAINS.
THIS WILL KEEP A DRY NORTHWEST FLOW ALOFT OVER THE OHIO VALLEY AS
HIGH PRESSURE AT THE SURFACE BUILDS FROM THE MIDWEST BEHIND THE
FRONT BEFORE SETTLING ACROSS THE OHIO VALLEY FOR THE MID AND LATTER
PORTIONS OF THIS COMING WEEK. MODELS DO SUGGEST THAT WEAK DIURNAL
INSTABILITY COULD DEVELOP TUESDAY AFTERNOON WITH COOL NORTHWEST FLOW
ALOFT, SO WILL KEEP A SLIGHT CHANCE OF SHOWERS OVER OUR SOUTHEAST
COUNTIES IN CENTRAL KY.
AS HIGH PRESSURE SETTLES IN, HIGH TEMPERATURES WILL BE SEVERAL
DEGREES BELOW NORMAL BY MID NEXT WEEK, PEAKING OUT ONLY IN THE UPPER
70S AND LOWER 80S WEDNESDAY AND THURSDAY. HUMIDITY LEVELS (SURFACE
DEWPOINTS) WILL BE LOW AS WELL. LOW TEMPERATURES THURSDAY AND FRIDAY
MORNINGS SHOULD RANGE FROM THE MID 50S TO LOWER 60S. BY NEXT
WEEKEND, TEMPERATURES SHOULD RETURN TO NEAR OR ABOVE NORMAL AS
SUMMER AIR RETURNS.
&&
.AVIATION (12Z TAF UPDATE)...
ISSUED AT 635 AM EDT SUN AUG 9 2015
QUIET WEATHER CONDITIONS ARE EXPECTED AT THE TAF SITES TODAY. SOME
PATCHY FOG WILL BE POSSIBLE AT THE TEMRINALS THIS
MORNING...ESPECIALLY KBWG AND KLEX. THIS FOG SHOULD MIX OUT BY
09/13Z WITH VFR CONDITIONS RETURNING. VFR CONDITIONS ARE EXPECTED
THROUGH THE DAY WITH LIGHT AND VARIABLE WINDS.
CLOUDS WILL BE ON THE INCREASE LATE THIS EVENING AHEAD OF AN
APPROACHING MID-LEVEL WAVE. PRECIPITATION ASSOCIATED WITH THIS
SYSTEM LOOKS TO OCCUR LATE IN THE FORECAST PERIOD...PERHAPS HOLDING
OFF UNTIL JUST AFTER THE FORECAST PERIOD.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
UPDATE.........RJS
SHORT TERM.....MJ
LONG TERM......TWF
AVIATION.......MJ
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
1051 AM EDT SUN AUG 9 2015
.UPDATE...
ISSUED AT 1050 AM EDT SUN AUG 9 2015
ABUNDANT LOW CLOUDS ARE LOCATED OUT AHEAD OF THE COLD FRONT WHICH
IS STRETCHING FROM THUNDER BAY...ALONG THE WESTERN LAKE SUPERIOR
SHORELINE AND THEN SOUTHWEST INTO CENTRAL MINNESOTA. STARTING TO
HAVE SOME CONCERNS THAT THESE WIDESPREAD AND FAIRLY THICK CLOUDS
WILL HAVE SOME DIFFICULTY BURNING OFF THROUGH THE DAY...WHICH WOULD
LIMIT INSTABILITY AND LIKELY THUNDERSTORM DEVELOPMENT OVER PARTS OF
THE WESTERN U.P.. IN ADDITION...A WEAK SHORTWAVE MOVING EAST
THROUGH CENTRAL MINNESOTA IS PRODUCING LIGHT SHOWERS AND PLENTY OF
MID CLOUDS. THAT WAVE AND ITS ASSOCIATED FEATURES SHOULD MOVE EAST
THROUGH THE UPPER GREAT LAKES REGION THIS AFTERNOON INTO THE
EVENING HOURS. WITH THAT FEATURE MOVING THROUGH...WON/T DEVIATE TOO
MUCH FROM THE GOING FORECAST/POPS AT THIS POINT...BUT MAY NEED TO
FOCUS DEVELOPMENT (POPS) ON THE EASTERN EDGE OF THE CLOUDS AND MORE
INTO THE CENTRAL U.P. WHERE THE INSTABILITY WILL BE GREATEST. THAT
WOULD BE MORE IN LINE WITH THE LATEST HRRR/RAP RUNS...WHICH HAVE THE
RIBBON OF BEST MLCAPE VALUES ALONG THAT DIFFERENTIAL HEATING GRADIENT
(KSAW TO CRYSTAL FALLS). &&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 532 AM EDT SUN AUG 9 2015
WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A VIGOROUS SHORTWAVE
MOVING ACROSS NRN ONTARIO. SEVERAL OTHER SHORTWAVES ACCOMPANIED BY
SHRA/TSTMS ARE NOTED MOVING ACROSS THE NRN AND CNTRL PLAINS. TAIL
END OF FORCING ASSOCIATED WITH NRN ONTARIO SHORTWAVE OVERTOP 850MB
THETA-E RIDGE HAS BEEN SUPPORTING ISOLD/SCT SHRA/TSTM DEVELOPMENT
OVE WRN UPPER MI SINCE SHORTLY AFTER MIDNIGHT. DESPITE LACK OF
INSTABILITY (MUCAPE NO HIGHER THAN 400J/KG)...A FEW OF THE STORMS
WERE FAIRLY STRONG AND LIKELY PRODUCED AT LEAST PEA-SIZE HAIL. RADAR
ESTIMATED INSTANTANEOUS PCPN RATES HAVE BEEN PRETTY IMPRESSIVE AS
WELL...THOUGH RAINFALL CORES HAVE BEEN VERY SMALL.
00Z MODEL RUNS INCLUDING HOURLY RAP/HRRR RUNS SINCE 00Z INDICATE
ONGOING ISOLD/SCT SHRA/TSTMS WILL PROBABLY PERSIST AND REACH CNTRL
UPPER MI BEFORE DIMINISHING AND PERHAPS ENDING FOR THE MOST PART.
ATTENTION THEN TURNS TO THE AFTN. BUILDING INSTABILITY AND
APPROACHING COLD FRONT WILL SPARK A NEW ROUND OF SHRA/TSTMS WITH
MODELS POINTING TOWARD BARAGA/MARQUETTE/IRON COUNTIES AS THE LIKELY
FOCAL AREA FOR GREATEST COVERAGE OF DEVELOPMENT. NAM CONTINUES TO BE
VERY AGGRESSIVE BUILDING MLCAPES TO OVER 1500J/KG OVER WRN UPPER MI
AND AS HIGH AS NEARLY 2500J/KG. GFS TOPS OUT AROUND 1000J/KG WHILE
RECENT RAP RUNS ONLY TOP OUT NEAR 500J/KG. 21Z SREF INDICATES ABOUT
A 30PCT CHANCE OF MLCAPES INCREASING TO OVER 1000J/KG...SO THE NAM
DEFINITELY LOOKS LIKE A HIGH OUTLIER. A REASONABLE EXPECTATION IS
PROBABLY MLCAPES OF 500-1000J/KG. WITH DEEP LAYER SHEAR TOPPING OUT
AROUND 25KT...SVR RISK APPEARS MINIMAL...UNLESS INSTABILITY BUILDS
HIGHER THAN CURRENTLY EXPECTED. SOME SMALL HAIL WILL BE POSSIBLE
WITH THE STRONGEST STORMS. ALSO...EXPECT BRIEF LOCALLY HVY RAINFALL.
SHRA/TSTMS WILL SHIFT E TONIGHT AND DIMINISH. LIGHT WINDS IN THE
VCNTY OF THE PASSING FRONT ALONG WITH EXPECTED RAINFALL SHOULD
RESULT IN FOG DEVELOPING...ESPECIALLY ACROSS SCNTRL/SE UPPER MI.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 444 AM EDT SUN AUG 9 2015
AT 12Z MONDAY THE APEX OF THE 500MB TROUGH /EXTENDING FROM THE LOW
OVER JAMES BAY/ WILL BE OVERHEAD...WITH SHOWERS EXITING THE E CWA.
A SECONDARY SHORTWAVE SWINGING AROUND THE MAIN TROUGH WILL PUSH IN
FROM THE NW MONDAY NIGHT. WITH LIMITED MOISTURE...DO NOT EXPECT MUCH
IN THE WAY OF PRECIP. MODELS DO SHOW SOME INCREASE IN LOW LEVEL
MOISTURE...BELOW 800MB...WITH THE BEST MOISTURE ASSISTED BY N-NNW
FLOW OVER THE E THIRD OF UPPER MI.
EXPECT A MAINLY N WIND TO REMAIN JUST ABOVE THE SFC THROUGH THE
FIRST HALF OF THE WORK WEEK. 850MB TEMPS OF 8-11C WILL HELP KEEP
AFTERNOON SFC TEMPS IN THE 70S MONDAY-WEDNESDAY. AT THIS POINT
TUESDAY LOOKS TO BE THE COOLEST DAY...WITH A FEW READINGS IN THE
UPPER 60S ALONG LAKE SUPERIOR AS A LARGE AREA OF HIGH PRESSURE AT
THE SFC SETTLES OVERHEAD.
THE BROAD 500MB TROUGH WILL EXIT E WEDNESDAY...WITH RIDGING BUILDING
ACROSS THE UPPER GREAT LAKES REGION. THE DRY WEATHER WILL BE SHORT
LIVED AS A SLIGHT CHANCE OF RETURNS OVER LAKE SUPERIOR WEDNESDAY
NIGHT...AS THE 500MB RIDGE BECOMES SUPPRESSED SETTING THE STAGE FOR
NW FLOW ALOFT AND ADDITIONAL DISTURBANCES/UNSETTLED WX THROUGH
THURSDAY NIGHT. THE SFC LOW WELL TO OUR N IN CANADA WILL DRAG A COLD
FRONT NW-SE FROM AROUND 21Z THURSDAY TO 12Z FRIDAY.
DRY WEATHER SHOULD RETURN AGAIN AS THE COLD FRONT SLIPS ACROSS LOWER
MI FRIDAY AND HIGH PRESSURE BUILDS IN FOR THE START OF THE WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 752 AM EDT SUN AUG 9 2015
SHOWERS OVERNIGHT HAVE AIDED DEVELOPMENT OF MVFR CONDITIONS AT KIWD.
IT MAY NOT BE UNTIL AFTN THAT CONDITIONS IMPROVE TO VFR. AT KSAW...
FOG/STRATUS AND LIFR CONDITIONS ARE IMPROVING. MAY SEE LIFR
CONDITIONS AT TIMES FOR THE NEXT HR OR SO. OTHERWISE....VFR
CONDTIONS SHOULD BE THE RULE AT KIWD/KCMX/KSAW TODAY. SHRA/TSTMS
WILL LIKELY DEVELOP DURING THE AFTN AS A COLD FRONT APPROACHES. WITH
KSAW HAVING THE BEST CHC OF SEEING PCPN...SHRA AND VCTS HAVE BEEN
INCLUDED IN FCST LATE THIS AFTN/EVENING. IF ANY TERMINALS SEE
PCPN...IT`S NOT OUT OF THE QUESTION THAT THERE COULD BE BRIEF IFR
CONDITIONS. OTHERWISE...VFR CONDITIONS SHOULD CONTINUE TONIGHT
KIWD/KCMX. PROVIDED THAT IT DOES RAIN...FOG/IFR CONDITIONS ARE
EXPECTED AT KSAW OVERNIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 532 AM EDT SUN AUG 9 2015
COLD FRONT MOVING ACROSS LAKE SUPERIOR THIS AFTN AND TONIGHT WILL
LEAD TO A WIND SHIFT FROM SOUTHERLY TO NORTHWESTERLY. WITH GENERALLY
A WEAK PRES GRADIENT...WINDS SHOULD REMAIN UNDER 20KT TODAY THRU
MON. MON NIGHT/TUE...GRADIENT TIGHTENS A BIT AHEAD OF APPROACHING
SFC HIGH PRES...SO WINDS OVER THE E HALF OF LAKE SUPERIOR WILL
PROBABLY BEGIN TO GUST MORE FREQUENTLY TO AROUND 20KT. ARRIVAL OF
SFC HIGH PRES RIDGE WILL RESULT IN WINDS UNDER 15KT TUE NIGHT/WED.
WINDS WILL THEN INCREASE SOME INTO THU AHEAD OF THE NEXT APPROACHING
COLD FRONT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...SRF
SHORT TERM...ROLFSON
LONG TERM...KF
AVIATION...ROLFSON
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
753 AM EDT SUN AUG 9 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 532 AM EDT SUN AUG 9 2015
WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A VIGOROUS SHORTWAVE
MOVING ACROSS NRN ONTARIO. SEVERAL OTHER SHORTWAVES ACCOMPANIED BY
SHRA/TSTMS ARE NOTED MOVING ACROSS THE NRN AND CNTRL PLAINS. TAIL
END OF FORCING ASSOCIATED WITH NRN ONTARIO SHORTWAVE OVERTOP 850MB
THETA-E RIDGE HAS BEEN SUPPORTING ISOLD/SCT SHRA/TSTM DEVELOPMENT
OVE WRN UPPER MI SINCE SHORTLY AFTER MIDNIGHT. DESPITE LACK OF
INSTABILITY (MUCAPE NO HIGHER THAN 400J/KG)...A FEW OF THE STORMS
WERE FAIRLY STRONG AND LIKELY PRODUCED AT LEAST PEA-SIZE HAIL. RADAR
ESTIMATED INSTANTANEOUS PCPN RATES HAVE BEEN PRETTY IMPRESSIVE AS
WELL...THOUGH RAINFALL CORES HAVE BEEN VERY SMALL.
00Z MODEL RUNS INCLUDING HOURLY RAP/HRRR RUNS SINCE 00Z INDICATE
ONGOING ISOLD/SCT SHRA/TSTMS WILL PROBABLY PERSIST AND REACH CNTRL
UPPER MI BEFORE DIMINISHING AND PERHAPS ENDING FOR THE MOST PART.
ATTENTION THEN TURNS TO THE AFTN. BUILDING INSTABILITY AND
APPROACHING COLD FRONT WILL SPARK A NEW ROUND OF SHRA/TSTMS WITH
MODELS POINTING TOWARD BARAGA/MARQUETTE/IRON COUNTIES AS THE LIKELY
FOCAL AREA FOR GREATEST COVERAGE OF DEVELOPMENT. NAM CONTINUES TO BE
VERY AGGRESSIVE BUILDING MLCAPES TO OVER 1500J/KG OVER WRN UPPER MI
AND AS HIGH AS NEARLY 2500J/KG. GFS TOPS OUT AROUND 1000J/KG WHILE
RECENT RAP RUNS ONLY TOP OUT NEAR 500J/KG. 21Z SREF INDICATES ABOUT
A 30PCT CHANCE OF MLCAPES INCREASING TO OVER 1000J/KG...SO THE NAM
DEFINITELY LOOKS LIKE A HIGH OUTLIER. A REASONABLE EXPECTATION IS
PROBABLY MLCAPES OF 500-1000J/KG. WITH DEEP LAYER SHEAR TOPPING OUT
AROUND 25KT...SVR RISK APPEARS MINIMAL...UNLESS INSTABILITY BUILDS
HIGHER THAN CURRENTLY EXPECTED. SOME SMALL HAIL WILL BE POSSIBLE
WITH THE STRONGEST STORMS. ALSO...EXPECT BRIEF LOCALLY HVY RAINFALL.
SHRA/TSTMS WILL SHIFT E TONIGHT AND DIMINISH. LIGHT WINDS IN THE
VCNTY OF THE PASSING FRONT ALONG WITH EXPECTED RAINFALL SHOULD
RESULT IN FOG DEVELOPING...ESPECIALLY ACROSS SCNTRL/SE UPPER MI.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 444 AM EDT SUN AUG 9 2015
AT 12Z MONDAY THE APEX OF THE 500MB TROUGH /EXTENDING FROM THE LOW
OVER JAMES BAY/ WILL BE OVERHEAD...WITH SHOWERS EXITING THE E CWA.
A SECONDARY SHORTWAVE SWINGING AROUND THE MAIN TROUGH WILL PUSH IN
FROM THE NW MONDAY NIGHT. WITH LIMITED MOISTURE...DO NOT EXPECT MUCH
IN THE WAY OF PRECIP. MODELS DO SHOW SOME INCREASE IN LOW LEVEL
MOISTURE...BELOW 800MB...WITH THE BEST MOISTURE ASSISTED BY N-NNW
FLOW OVER THE E THIRD OF UPPER MI.
EXPECT A MAINLY N WIND TO REMAIN JUST ABOVE THE SFC THROUGH THE
FIRST HALF OF THE WORK WEEK. 850MB TEMPS OF 8-11C WILL HELP KEEP
AFTERNOON SFC TEMPS IN THE 70S MONDAY-WEDNESDAY. AT THIS POINT
TUESDAY LOOKS TO BE THE COOLEST DAY...WITH A FEW READINGS IN THE
UPPER 60S ALONG LAKE SUPERIOR AS A LARGE AREA OF HIGH PRESSURE AT
THE SFC SETTLES OVERHEAD.
THE BROAD 500MB TROUGH WILL EXIT E WEDNESDAY...WITH RIDGING BUILDING
ACROSS THE UPPER GREAT LAKES REGION. THE DRY WEATHER WILL BE SHORT
LIVED AS A SLIGHT CHANCE OF RETURNS OVER LAKE SUPERIOR WEDNESDAY
NIGHT...AS THE 500MB RIDGE BECOMES SUPPRESSED SETTING THE STAGE FOR
NW FLOW ALOFT AND ADDITIONAL DISTURBANCES/UNSETTLED WX THROUGH
THURSDAY NIGHT. THE SFC LOW WELL TO OUR N IN CANADA WILL DRAG A COLD
FRONT NW-SE FROM AROUND 21Z THURSDAY TO 12Z FRIDAY.
DRY WEATHER SHOULD RETURN AGAIN AS THE COLD FRONT SLIPS ACROSS LOWER
MI FRIDAY AND HIGH PRESSURE BUILDS IN FOR THE START OF THE WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 752 AM EDT SUN AUG 9 2015
SHOWERS OVERNIGHT HAVE AIDED DEVELOPMENT OF MVFR CONDITIONS AT KIWD.
IT MAY NOT BE UNTIL AFTN THAT CONDITIONS IMPROVE TO VFR. AT KSAW...
FOG/STRATUS AND LIFR CONDITIONS ARE IMPROVING. MAY SEE LIFR
CONDITIONS AT TIMES FOR THE NEXT HR OR SO. OTHERWISE....VFR
CONDTIONS SHOULD BE THE RULE AT KIWD/KCMX/KSAW TODAY. SHRA/TSTMS
WILL LIKELY DEVELOP DURING THE AFTN AS A COLD FRONT APPROACHES. WITH
KSAW HAVING THE BEST CHC OF SEEING PCPN...SHRA AND VCTS HAVE BEEN
INCLUDED IN FCST LATE THIS AFTN/EVENING. IF ANY TERMINALS SEE
PCPN...IT`S NOT OUT OF THE QUESTION THAT THERE COULD BE BRIEF IFR
CONDITIONS. OTHERWISE...VFR CONDITIONS SHOULD CONTINUE TONIGHT
KIWD/KCMX. PROVIDED THAT IT DOES RAIN...FOG/IFR CONDITIONS ARE
EXPECTED AT KSAW OVERNIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 532 AM EDT SUN AUG 9 2015
COLD FRONT MOVING ACROSS LAKE SUPERIOR THIS AFTN AND TONIGHT WILL
LEAD TO A WIND SHIFT FROM SOUTHERLY TO NORTHWESTERLY. WITH GENERALLY
A WEAK PRES GRADIENT...WINDS SHOULD REMAIN UNDER 20KT TODAY THRU
MON. MON NIGHT/TUE...GRADIENT TIGHTENS A BIT AHEAD OF APPROACHING
SFC HIGH PRES...SO WINDS OVER THE E HALF OF LAKE SUPERIOR WILL
PROBABLY BEGIN TO GUST MORE FREQUENTLY TO AROUND 20KT. ARRIVAL OF
SFC HIGH PRES RIDGE WILL RESULT IN WINDS UNDER 15KT TUE NIGHT/WED.
WINDS WILL THEN INCREASE SOME INTO THU AHEAD OF THE NEXT APPROACHING
COLD FRONT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KF
AVIATION...ROLFSON
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
855 AM PDT SUN AUG 9 2015
.SYNOPSIS...LIMITED MOISTURE HAS BEEN PULLED UP INTO NORTHWEST
ARIZONA AND SOUTHEAST NEVADA TODAY WHICH WILL LEAD TO ISOLATED
SHOWERS OR THUNDERSTORMS. DRY CONDITIONS CAN BE EXPECTED ELSEWHERE.
DEVELOPING LOW PRESSURE OFF THE WEST COAST AND HIGH PRESSURE OVER
NEW MEXICO WILL OPEN THE DOOR FOR MONSOON MOISTURE TO RETURN FOR THE
MIDDLE OF THE WEEK. DURING THIS TIME IT APPEARS THE BEST CHANCES FOR
THUNDERSTORMS WILL BE FROM LAS VEGAS SOUTH AND EAST.
&&
.UPDATE...SATELLITE AND RADAR LOOPS SHOWED ISOLATED SHOWERS POPPING
THIS MORNING OVER NORTHWEST ARIZONA EASTERN PORTIONS OF CLARK
COUNTY. A LOOK BACK AT THE IR SATELLITE LOOP REVEALS THAT THIS
MOISTURE WAS TRANSPORTED UP FROM SOUTH CENTRAL ARIZONA IN A
SOUTHEAST FLOW THAT DEVELOPED IN THE 850-700 LAYER. THIS IS
INDICATED IN MOST MODELS EVEN THOUGH THE FLOW THE H5 AND ABOVE FLOW
IS STILL DRY SOUTHWEST. RADAR CROSS SECTIONS SHOW INDIVIDUAL CELLS
EXTEND FROM 10-25 KFT MSL AND NO LIGHTNING HAS BEEN DETECTED YET.
LOCAL HIGH RES MODELS AND THE HRRR ALL INDICATE CONVECTION
CONTINUING ACROSS MOHAVE COUNTY AND NORTHEAST CLARK COUNTY THROUGH
THE AFTERNOON. A BRIEF THUNDERSTORM CANNOT BE COMPLETELY RULED OUT
OVER EASTERN PARTS OF THE LAS VEGAS VALLEY OR THE NEARBY MOUNTAINS.
THE FORECAST WAS UPDATED TO REFLECT THESE TRENDS.
&&
.AVIATION...FOR MCCARRAN...A FEW SHOWERS OR THUNDERSTORMS WILL BE
POSSIBLE IN THE PEACH SPRINGS CORRIDOR AND OVER EASTERN CLARK COUNTY
TODAY DUE TO MOISTURE THAT WAS PULLED UP FROM SOUTH CENTRAL ARIZONA
OVERNIGHT. WINDS WILL FAVOR AN EAST TO SOUTHEAST DIRECTION DURING
THE AFTERNOON AND SOUTHWEST OVERNIGHT.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...FEW-SCT CLOUDS AOA 12K FEET WITH ISOLATED SHOWERS OR
THUNDERSTORMS ARE EXPECTED OVER NORTHWEST ARIZONA AND SOUTHEAST
NEVADA TODAY. SMOKE FROM THE 1 WILLOW FIRE NEAR KEED IS EXPECTED TO
DRIFT NORTH AND MAY IMPACT SITES ALONG THE COLORADO RIVER VALLEY AND
ACROSS NORTHWEST ARIZONA. OTHERWISE QUIET CONDITIONS ARE EXPECTED
WITH SOUTHERLY WINDS INCREASING TO 10-20 KTS DURING THE AFTERNOON
HOURS.
&&
.PREV DISCUSSION...
208 AM PDT SUN AUG 9 2015
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT.
CONDITIONS REMAIN QUIET THIS MORNING. THE MAIN ITEM OF CONCERN IS
THE 1 WILLOW FIRE BETWEEN MOHAVE VALLEY AND TOPOCK AND THE SMOKE
ASSOCIATED WITH IT. A TRAINED SPOTTER REPORTED VISIBILITY DOWN TO 3/4
MILE NEAR GRAND CANYON WEST (SOME 90 MILES AWAY FROM THE FIRE) LAST
EVENING AND HAVE KEPT SMOKE IN THE FORECAST FOR TODAY. BASED ON
RADAR DATA SMOKE ACTIVITY HAS BEEN SOMEWHAT TEMPERED OVERNIGHT AND
THUS HAVE REDUCED THE AREAL EXTENT OF SMOKE AFTER 12Z. ONCE THE SUN
COMES UP WE`LL HAVE TO RE-EVALUATE BASED ON SATELLITE IMAGERY AND
MAKE FURTHER ADJUSTMENTS. SMOKE IS EXPECTED TO CONTINUE TO DRIFT
NORTH-NORTHEAST DURING THE MORNING...BUT 700MB FLOW DOES BACK
SLIGHTLY BY THE AFTERNOON AND COULD DIRECT SMOKE UP THE COLORADO
RIVER VALLEY...OR EVEN TOWARD LAS VEGAS (IF THE FIRE REMAINS ACTIVE
ENOUGH TO PRODUCE A PLUME).
OUTSIDE OF THE SMOKE...MAINLY QUIET CONDITIONS ARE EXPECTED TODAY
AND MONDAY AS DRY SOUTHWEST FLOW REMAINS IN PLACE ACROSS THE REGION.
THIS WILL HELP KEEP THE BRUNT OF THE MONSOON MOISTURE EAST OF THE
FORECAST AREA. LIKE YESTERDAY...THE BOUNDARY BETWEEN DRY AND MOIST
WILL BE SOMEWHERE IN THE VICINITY OF THE EASTERN MOHAVE COUNTY LINE
BOTH TODAY AND MONDAY. THIS MEANS THAT A STRAY SHOWER IS
POSSIBLE...BUT THE CHANCES ARE LARGELY BELOW 10 PERCENT. A WEAK WAVE
MOVING THROUGH THE FLOW WILL ACT TO HELP ENHANCE SOUTHERLY BREEZES
THIS AFTERNOON...AND THESE BREEZES WILL CONTINUE THROUGH MONDAY.
FOR TUESDAY...I`VE CARRIED ON THE SLIGHT CHANCE OF PRECIPITATION
OVER MOHAVE AND FAR EASTERN LINCOLN COUNTIES. THE GOING FORECAST
APPEARS TO BE LEANED HEAVILY TOWARD THE GFS...AND WITH IT`S RECENT
TRACK RECORD I WAS RELUCTANT TO CHANGE IT TOO MUCH. HOWEVER IT`S
WORTH NOTING THAT MODEL AGREEMENT IS POOR ON THE PLACEMENT OF
MOISTURE AND INSTABILITY THERE...WITH THE ECMWF KEEPING THINGS DRY
AND STABLE UNTIL WEDNESDAY.
.LONG TERM...WEDNESDAY THROUGH SATURDAY.
NOT MUCH CHANGE FROM PREVIOUS THINKING. CWA STILL REMAINS CAUGHT
BETWEEN DRY SOUTHWEST FLOW FARTHER TO THE NORTHWEST /ASSOCIATED WITH
A PACIFIC TROUGH/ AND MOIST SOUTH TO SOUTHEAST FLOW TO THE EAST
/ASSOCIATED WITH A BIG RIDGE TO THE EAST/. THE MODELS DIFFER A BIT
IN THEIR HANDLING OF THE LARGE SCALE FEATURES...WITH THE ECMWF
HAVING TRENDED TOWARD A STRONGER RIDGE DRIFTING FARTHER WEST /NEARLY
OVERHEAD BY SATURDAY/ AND THE GFS LOOKING NEARLY IDENTICAL TO ITS
PREVIOUS RUNS. MADE VERY LITTLE CHANGE TO THE FORECAST...WHICH
DEPICTS THUNDERSTORM CHANCES ROUGHLY FROM LAS VEGAS EASTWARD ON
WEDNESDAY AND THURSDAY...FOLLOWED BY A SLIGHT DRYING TREND FRIDAY
AND SATURDAY. TEMPERATURES ARE A MINOR CONCERN. THE ECMWF...SINCE IT
SHOWS THE RIDGE RETROGRADING TOWARD OUR AREA...RAMPS HIGH TEMPS UP
TO NEAR EXCESSIVE HEAT WARNING CRITERIA BY SATURDAY. SINCE THIS IS
THE FIRST RUN OF THE ECMWF TO SHOW THIS TREND...AND THE GFS DOES NOT
SUPPORT IT...CONSIDER IT TO BE A LOW PROBABILITY SOLUTION AT THIS
TIME...AND FORECAST REMAINS ABOUT FIVE DEGREES BELOW THE ECE MOS
GUIDANCE. BUT IT IS SOMETHING TO KEEP IN THE BACK OF THE MIND.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
UPDATE/AVIATION...ADAIR
SHORT TERM...WOLCOTT
LONG TERM.............MORGAN
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1040 AM EDT SUN AUG 9 2015
.SYNOPSIS...
ANOTHER NICE DAY IS EXPECTED ACROSS THE NORTH COUNTRY
WITH MAINLY DRY CONDITIONS AND NEAR NORMAL TEMPERATURES. AN ISOLATED
SHOWER OR SPRINKLE IS POSSIBLE ACROSS NORTHEAST VERMONT THIS
AFTERNOON. OTHERWISE...DRY CONDITIONS WITH SLIGHTLY ABOVE NORMAL
TEMPERATURES ARE FORECASTED FOR MONDAY...BEFORE SHOWERS ARRIVE ON
MONDAY NIGHT INTO TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1040 AM EDT SUNDAY...JUST A FEW MINOR UPDATES NEEDED TO
THIS MORNING`S FORECAST AT THIS TIME, MAINLY TO ADJUST FOR CURRENT
TEMP AND SKY COVER TRENDS. TEMPS RUNNING A DEGREE OR TWO WARMER
THAN PREVIOUS FORECAST SO HAVE BUMPED UP SLIGHTLY THERE. OF
GREATER INTEREST IS AN AREA OF FOG AND LOW CLOUDS OVER THE UPPER
ST. LAWRENCE AND MONTREAL WHICH IS TRYING TO SAG SOUTHWARD ACROSS
THE BORDER INTO NORTHERN NEW YORK. ITS HAVING A TOUGH TIME THOUGH
WITH THE STRONG SUBSIDENCE OVER THE BTV CWA AND EXPECT AS MIXING
GETS GOING HERE IN A COUPLE OF HOURS THIS AREA WILL DISSIPATE.
WE`LL BE LEFT WITH SOME FAIR WEATHER CUMULUS BECOMING SCT-BKN
THROUGH THE AFTERNOON AND DISSIPATING TOWARDS SUNSET. REST OF
FORECAST UNCHANGED.
PREVIOUS DISCUSSION...FORECAST FOCUS TODAY WILL BE CHANCE FOR AN
ISOLATED SHOWER ACROSS THE NORTHEAST KINGDOM OF VT. CRNT WATER
VAPOR SHOWS MID/UPPER LVL TROF CONTS...WITH WEAK S/W ENERGY DIVING
SOUTH FROM EASTERN CANADA. ALSO...WATER VAPOR SHOWS VERY DRY AIR
AHEAD OF THIS SYSTEM...SO ANY PRECIP CHCS TODAY WILL BE VERY
ISOLATED AND CONFINED TO THE NORTHEAST KINGDOM OR MTNS OF NORTHERN
VT. BTV 4KM IS MOST AGGRESSIVE WITH SHOWING QPF AND ASSOCIATED
COMPOSITE REFLECTIVITY RETURNS ACROSS MOST OF THE HIGHER TRRN OF
VT THIS AFTN...BUT GIVEN PROGGED SOUNDING MOISTURE
PROFILES...THINKING THIS IS OVERDONE. WL USE A BLEND OF NAM/GFS
AND HRRR TO MENTION SCHC WITH A SMALL AREA OF CHC POPS ACROSS
ESSEX COUNTY VT. REST OF CWA WILL REMAIN DRY. TEMPS WILL BE
SEVERAL DEGREES WARMER THAN YESTERDAY WITH HIGHS GENERALLY IN THE
70S TO NEAR 80F.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
AS OF 345 AM EDT SUNDAY...OUR NICE PERIOD OF DRY
WEATHER WILL BE COMING TO AN END BY TUESDAY...AS MID/UPPER LVL TROF
AND ASSOCIATED SFC LOW PRES IMPACT THE NE CONUS. FOR MONDAY...BEST
850 TO 500MB MOISTURE IS WEST OF OUR CWA THRU 00Z..ALONG WITH
FORCING ASSOCIATED WITH INITIAL 5H VORT. WILL CONT TO MENTION CHC
POPS TWD 00Z TUESDAY ACROSS THE SLV AND WESTERN DACKS. PROGGED 85H
TEMPS WARM BTWN 12-14C BY 18Z MONDAY...SUPPORTING M/U 70S MTN TOWNS
TO L/M 80S WARMER VALLEYS.
OVERALL...NAM/GFS AND ECMWF HAVE COME INTO PRETTY GOOD AGREEMENT
WITH HANDLING THE DEEPENING OF MID/UPPER LVL TROF ACROSS THE GREAT
LAKES AND SFC LOW PRES TRACKING FROM THE OHIO VALLEY MONDAY NIGHT
INTO THE SLV BY TUES. IN ADDITION...MODELS HAVE TRENDED SEVERAL
HOURS SLOWER WITH THE PRECIP ARRIVE ON MONDAY NIGHT INTO TUESDAY
ACROSS OUR CWA...WITH HEAVIEST QPF AXIS OF UP TO 1.0 OF RAIN
EXPECTED OVER NORTHERN NY BY TUES AFTN. LOW LEVEL FORCING/ ADVECTION
OF MOISTURE IS IMPRESSIVE ASSOCIATED WITH NOSE OF 85H JET OF 45 TO
50 KNOTS IMPACTING OUR CWA BY 12Z TUESDAY. GFS/NAM SHOW A STRONG
BAND OF 850 TO 700MB FGEN FORCING...ALONG WITH GOOD LVLL MOISTURE
CONVERGENCE LIFTING FROM SW TO NE ACRS OUR CWA BTWN 09Z AND 18Z
TUESDAY.
HAVE NOTED SOME HIGHER RESOLUTION MODELS SHOWING IMPACTS OF
SE TO SOUTHWEST WINDS ON THE ASSOCIATED QPF FIELDS WITH SOME
SHADOWING OVER THE CPV AND PARTS OF THE NEK. GIVEN THE MOISTURE FEED
WITH PWS AROUND 1.50" AND GOOD UPPER LEVEL DYNAMICS WITH APPROACHING
TROF AND HEIGHT FALLS...A WIDESPREAD RAINFALL IS VERY LIKELY LATE
MONDAY NIGHT INTO TUESDAY. WILL CONT THE TREND AND MENTION CAT POPS
ACRS OUR CWA...BUT TRRN WILL INFLUENCE QPF FIELDS....WITH HIGHEST
VALUES OF UP TO 1.0 OCCURRING ACRS THE NORTHERN NY/HIGH PEAKS
REGION...GIVEN THE LLVL JET ORIENTATION. MEANWHILE...VALUES ACROSS
VT WILL RANGE FROM 0.25 TO 0.75" WITH HIGHEST AMOUNTS ON SE UPSLOPE
AREAS OF THE GREEN MTNS.
SOUNDINGS SHOW RIDGETOP WINDS BTWN 45 AND 50 KNOTS ON TUESDAY
MORNING...BUT INVERSION LEVEL IS AROUND 2000 FT....SUPPORTING
MIXED LAYER WINDS TO THE SURFACE UP TO 35 MPH OR SO ALONG THE
WESTERN SLOPES AND HIGHER TRRN. TEMPS TUES WILL BE TRICKY WITH
1000 TO 500MB THICKNESS RIDGE OVERHEAD...BUT LOTS OF CLOUDS AND
PRECIP AROUND. THINKING A FEW BREAKS WILL DEVELOP IN MID LVL DRY
SLOT OVER THE SLV/WESTERN DACKS AND THIS AREA WILL REACH
80F...WHILE MOST OF THE OTHER SITES STAY IN THE M/U 60S MTNS TO
L/M 70S CPV/SOUTHERN VT.
A RUMBLE OF THUNDER ASSOCIATED WITH THE DYNAMICS CANNOT BE RULED
OUT ON TUESDAY MORNING...WITH ANOTHER CHC OF A RUMBLE ON TUES AFTN
IN THE WARM SECTOR OVER SLV. ALSO...NOTED WEAK ELEVATED
INSTABILITY LAYER WITH ML CAPE VALUES AROUND 400 J/KG ON MONDAY
NIGHT/TUESDAY MORNING...ASSOCIATED WITH NOSE OF 85H JET AND STRONG
LLVL WAA.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 354 AM EDT SUNDAY...RATHER ACTIVE WEATHER WITH CHANCE OF
SHOWERS FOR MUCH OF THE PERIOD AS UPPER LEVEL TROUGH REMAINS OVER
THE EAST.
WEAK SURFACE BOUNDARY WILL MOVE SLOWLY EAST OF THE AREA TUESDAY
NIGHT...WITH HIGHEST PRECIPITABLE WATER VALUES SHIFTING TO THE EAST
AS WELL. UPPER LEVEL LOW LAGS BEHIND HOWEVER...SO WHILE HIGHEST
CHANCE OF SHOWERS WILL BE DURING THE EVENING...THERE WILL BE A
CONTINUED CHANCE FOR A FEW SHOWERS DURING THE OVERNIGHT AS WELL.
WITH UPPER LEVEL LOW AND ASSOCIATED COLD POOL ALOFT STILL OVER THE
REGION ON WEDNESDAY...WE CAN EXPECT MORE CLOUDS AND A CONTINUED
CHANCE OF SHOWERS. WEST TO NORTHWEST UPSLOPE FLOW WILL HELP PROVIDE
SOURCE OF LIFT FOR BETTER COVERAGE OVER THE HIGHER TERRAIN. LIMITED
INSTABILITY...BUT AN ISOLATED THUNDERSTORM ALSO POSSIBLE.
UPPER TROUGH SLOW TO DEPART THURSDAY...SO STILL CHANCE OF A FEW
SHOWERS. DRIER CONDITIONS LATER THURSDAY INTO FRIDAY MORNING WITH
SHORTWAVE RIDGING ALOFT AT 500MB. FROM FRIDAY ONWARD YET ANOTHER
UPPER LEVEL TROUGH WILL APPROACH FROM THE NORTHERN GREAT LAKES
REGION AND RE-ESTABLISH THE EASTERN US TROUGH AND A CHANCE FOR MORE
SHOWERS AND A FEW WIDELY SCATTERED STORMS.
AS FOR TEMPS...MAX TEMPS WILL AVERAGE SEVERAL DEGREES BELOW NORMAL
WITH HIGHS MAINLY IN THE 70S...PERHAPS AROUND 80 IN SPOTS FRIDAY AND
SATURDAY. MINS WILL BE IN THE 50S TO AROUND 60...GENERALLY WITHIN
A FEW DEGREES OF NORMAL FOR MID AUGUST.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
THROUGH 12Z MONDAY...MAINLY VFR EXPECTED...WITH THE EXCEPTION OF
SOME IFR/LIFR FOG/BR EARLY TODAY AT MPV/SLK AND AGAIN LATE
TONIGHT AT MPV/SLK/MSS. FOG/BR LIFTS BY AROUND 13Z TODAY WITH
CLEAR SKIES THIS MORNING GIVING WAY TO SCT-BKN DECK OF CUMULUS IN
THE AFTERNOON...WITH ALL SITES VFR. WINDS BECOME GENERALLY
NORTHERLY FROM 4-8 KNOTS TODAY...BUT WITH LIGHT FLOW...THEY WILL
BE LOCALLY VARIABLE. WINDS LIGHT/CALM TONIGHT...EXCEPT SE 8-10 KTS
AT RUT WITH DRAINAGE WIND.
OUTLOOK 12Z MONDAY THROUGH THURSDAY...
12Z MONDAY THROUGH 00Z TUESDAY...VFR.
00Z TUESDAY THROUGH 00Z WEDNESDAY...DETERIORATING CONDITIONS
LIKELY (MVFR POSSIBLE IFR) WITH PERIODS OF RAIN SHOWERS AND
STRATUS.
00Z WEDNESDAY ONWARD...VFR WITH PERIODS OF MVFR IN LINGERING
SCATTERED SHOWERS. SHOWERS DIMINISHING THURSDAY.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...TABER
NEAR TERM...LAHIFF/TABER
SHORT TERM...TABER
LONG TERM...RJS
AVIATION...RJS
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
740 AM EDT SUN AUG 9 2015
.SYNOPSIS...
ANOTHER NICE DAY IS EXPECTED ACROSS THE NORTH COUNTRY
WITH MAINLY DRY CONDITIONS AND NEAR NORMAL TEMPERATURES. AN ISOLATED
SHOWER OR SPRINKLE IS POSSIBLE ACROSS NORTHEAST VERMONT THIS
AFTERNOON. OTHERWISE...DRY CONDITIONS WITH SLIGHTLY ABOVE NORMAL
TEMPERATURES ARE FORECASTED FOR MONDAY...BEFORE SHOWERS ARRIVE ON
MONDAY NIGHT INTO TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 711 AM EDT SUNDAY...VERY MINOR CHANGES TO CRNT FCST THAT
INCLUDED ADJUSTING FOR LATEST SATL TRENDS AND PLACE THE LATEST OBS
INTO THE GRIDS. DEEPER MOISTURE ASSOCIATED WITH 5H VORT CONTS TO
MOVE ACROSS CENTRAL/EASTERN VT THIS MORNING....WITH WATER VAPOR
SHOWING LARGE SCALE AREA OF SUBSIDENCE DEVELOPING OVER NORTHERN
NY. THIS WILL RESULT IN MOSTLY SUNNY SKIES TODAY AND LIMIT OVERALL
COVERAGE OF ANY POTENTIAL SHOWERS. HIGHS WILL WARM INTO THE 70S TO
NEAR 80 MOST LOCATIONS WITH LIGHT NORTH WINDS.
FORECAST FOCUS TODAY WILL BE CHANCE FOR AN ISOLATED SHOWER ACROSS
THE NORTHEAST KINGDOM OF VT. CRNT WATER VAPOR SHOWS MID/UPPER LVL
TROF CONTS...WITH WEAK S/W ENERGY DIVING SOUTH FROM EASTERN
CANADA. ALSO...WATER VAPOR SHOWS VERY DRY AIR AHEAD OF THIS
SYSTEM...SO ANY PRECIP CHCS TODAY WILL BE VERY ISOLATED AND
CONFINED TO THE NORTHEAST KINGDOM OR MTNS OF NORTHERN VT. BTV 4KM
IS MOST AGGRESSIVE WITH SHOWING QPF AND ASSOCIATED COMPOSITE
REFLECTIVITY RETURNS ACROSS MOST OF THE HIGHER TRRN OF VT THIS
AFTN...BUT GIVEN PROGGED SOUNDING MOISTURE PROFILES...THINKING
THIS IS OVERDONE. WL USE A BLEND OF NAM/GFS AND HRRR TO MENTION
SCHC WITH A SMALL AREA OF CHC POPS ACROSS ESSEX COUNTY VT. REST OF
CWA WILL REMAIN DRY. TEMPS WILL BE SEVERAL DEGREES WARMER THAN
YESTERDAY WITH HIGHS GENERALLY IN THE 70S TO NEAR 80F.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
AS OF 345 AM EDT SUNDAY...OUR NICE PERIOD OF DRY
WEATHER WILL BE COMING TO AN END BY TUESDAY...AS MID/UPPER LVL TROF
AND ASSOCIATED SFC LOW PRES IMPACT THE NE CONUS. FOR MONDAY...BEST
850 TO 500MB MOISTURE IS WEST OF OUR CWA THRU 00Z..ALONG WITH
FORCING ASSOCIATED WITH INITIAL 5H VORT. WILL CONT TO MENTION CHC
POPS TWD 00Z TUESDAY ACROSS THE SLV AND WESTERN DACKS. PROGGED 85H
TEMPS WARM BTWN 12-14C BY 18Z MONDAY...SUPPORTING M/U 70S MTN TOWNS
TO L/M 80S WARMER VALLEYS.
OVERALL...NAM/GFS AND ECMWF HAVE COME INTO PRETTY GOOD AGREEMENT
WITH HANDLING THE DEEPENING OF MID/UPPER LVL TROF ACROSS THE GREAT
LAKES AND SFC LOW PRES TRACKING FROM THE OHIO VALLEY MONDAY NIGHT
INTO THE SLV BY TUES. IN ADDITION...MODELS HAVE TRENDED SEVERAL
HOURS SLOWER WITH THE PRECIP ARRIVE ON MONDAY NIGHT INTO TUESDAY
ACROSS OUR CWA...WITH HEAVIEST QPF AXIS OF UP TO 1.0 OF RAIN
EXPECTED OVER NORTHERN NY BY TUES AFTN. LOW LEVEL FORCING/ ADVECTION
OF MOISTURE IS IMPRESSIVE ASSOCIATED WITH NOSE OF 85H JET OF 45 TO
50 KNOTS IMPACTING OUR CWA BY 12Z TUESDAY. GFS/NAM SHOW A STRONG
BAND OF 850 TO 700MB FGEN FORCING...ALONG WITH GOOD LVLL MOISTURE
CONVERGENCE LIFTING FROM SW TO NE ACRS OUR CWA BTWN 09Z AND 18Z
TUESDAY.
HAVE NOTED SOME HIGHER RESOLUTION MODELS SHOWING IMPACTS OF
SE TO SOUTHWEST WINDS ON THE ASSOCIATED QPF FIELDS WITH SOME
SHADOWING OVER THE CPV AND PARTS OF THE NEK. GIVEN THE MOISTURE FEED
WITH PWS AROUND 1.50" AND GOOD UPPER LEVEL DYNAMICS WITH APPROACHING
TROF AND HEIGHT FALLS...A WIDESPREAD RAINFALL IS VERY LIKELY LATE
MONDAY NIGHT INTO TUESDAY. WILL CONT THE TREND AND MENTION CAT POPS
ACRS OUR CWA...BUT TRRN WILL INFLUENCE QPF FIELDS....WITH HIGHEST
VALUES OF UP TO 1.0 OCCURRING ACRS THE NORTHERN NY/HIGH PEAKS
REGION...GIVEN THE LLVL JET ORIENTATION. MEANWHILE...VALUES ACROSS
VT WILL RANGE FROM 0.25 TO 0.75" WITH HIGHEST AMOUNTS ON SE UPSLOPE
AREAS OF THE GREEN MTNS.
SOUNDINGS SHOW RIDGETOP WINDS BTWN 45 AND 50 KNOTS ON TUESDAY
MORNING...BUT INVERSION LEVEL IS AROUND 2000 FT....SUPPORTING
MIXED LAYER WINDS TO THE SURFACE UP TO 35 MPH OR SO ALONG THE
WESTERN SLOPES AND HIGHER TRRN. TEMPS TUES WILL BE TRICKY WITH
1000 TO 500MB THICKNESS RIDGE OVERHEAD...BUT LOTS OF CLOUDS AND
PRECIP AROUND. THINKING A FEW BREAKS WILL DEVELOP IN MID LVL DRY
SLOT OVER THE SLV/WESTERN DACKS AND THIS AREA WILL REACH
80F...WHILE MOST OF THE OTHER SITES STAY IN THE M/U 60S MTNS TO
L/M 70S CPV/SOUTHERN VT.
A RUMBLE OF THUNDER ASSOCIATED WITH THE DYNAMICS CANNOT BE RULED
OUT ON TUESDAY MORNING...WITH ANOTHER CHC OF A RUMBLE ON TUES AFTN
IN THE WARM SECTOR OVER SLV. ALSO...NOTED WEAK ELEVATED
INSTABILITY LAYER WITH ML CAPE VALUES AROUND 400 J/KG ON MONDAY
NIGHT/TUESDAY MORNING...ASSOCIATED WITH NOSE OF 85H JET AND STRONG
LLVL WAA.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 354 AM EDT SUNDAY...RATHER ACTIVE WEATHER WITH CHANCE OF
SHOWERS FOR MUCH OF THE PERIOD AS UPPER LEVEL TROUGH REMAINS OVER
THE EAST.
WEAK SURFACE BOUNDARY WILL MOVE SLOWLY EAST OF THE AREA TUESDAY
NIGHT...WITH HIGHEST PRECIPITABLE WATER VALUES SHIFTING TO THE EAST
AS WELL. UPPER LEVEL LOW LAGS BEHIND HOWEVER...SO WHILE HIGHEST
CHANCE OF SHOWERS WILL BE DURING THE EVENING...THERE WILL BE A
CONTINUED CHANCE FOR A FEW SHOWERS DURING THE OVERNIGHT AS WELL.
WITH UPPER LEVEL LOW AND ASSOCIATED COLD POOL ALOFT STILL OVER THE
REGION ON WEDNESDAY...WE CAN EXPECT MORE CLOUDS AND A CONTINUED
CHANCE OF SHOWERS. WEST TO NORTHWEST UPSLOPE FLOW WILL HELP PROVIDE
SOURCE OF LIFT FOR BETTER COVERAGE OVER THE HIGHER TERRAIN. LIMITED
INSTABILITY...BUT AN ISOLATED THUNDERSTORM ALSO POSSIBLE.
UPPER TROUGH SLOW TO DEPART THURSDAY...SO STILL CHANCE OF A FEW
SHOWERS. DRIER CONDITIONS LATER THURSDAY INTO FRIDAY MORNING WITH
SHORTWAVE RIDGING ALOFT AT 500MB. FROM FRIDAY ONWARD YET ANOTHER
UPPER LEVEL TROUGH WILL APPROACH FROM THE NORTHERN GREAT LAKES
REGION AND RE-ESTABLISH THE EASTERN US TROUGH AND A CHANCE FOR MORE
SHOWERS AND A FEW WIDELY SCATTERED STORMS.
AS FOR TEMPS...MAX TEMPS WILL AVERAGE SEVERAL DEGREES BELOW NORMAL
WITH HIGHS MAINLY IN THE 70S...PERHAPS AROUND 80 IN SPOTS FRIDAY AND
SATURDAY. MINS WILL BE IN THE 50S TO AROUND 60...GENERALLY WITHIN
A FEW DEGREES OF NORMAL FOR MID AUGUST.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
THROUGH 12Z MONDAY...MAINLY VFR EXPECTED...WITH THE EXCEPTION OF
SOME IFR/LIFR FOG/BR EARLY TODAY AT MPV/SLK AND AGAIN LATE
TONIGHT AT MPV/SLK/MSS. FOG/BR LIFTS BY AROUND 13Z TODAY WITH
CLEAR SKIES THIS MORNING GIVING WAY TO SCT-BKN DECK OF CUMULUS IN
THE AFTERNOON...WITH ALL SITES VFR. WINDS BECOME GENERALLY
NORTHERLY FROM 4-8 KNOTS TODAY...BUT WITH LIGHT FLOW...THEY WILL
BE LOCALLY VARIABLE. WINDS LIGHT/CALM TONIGHT...EXCEPT SE 8-10 KTS
AT RUT WITH DRAINAGE WIND.
OUTLOOK 12Z MONDAY THROUGH THURSDAY...
12Z MONDAY THROUGH 00Z TUESDAY...VFR.
00Z TUESDAY THROUGH 00Z WEDNESDAY...DETERIORATING CONDITIONS
LIKELY (MVFR POSSIBLE IFR) WITH PERIODS OF RAIN SHOWERS AND
STRATUS.
00Z WEDNESDAY ONWARD...VFR WITH PERIODS OF MVFR IN LINGERING
SCATTERED SHOWERS. SHOWERS DIMINISHING THURSDAY.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...TABER
NEAR TERM...TABER
SHORT TERM...TABER
LONG TERM...RJS
AVIATION...RJS
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
713 AM EDT SUN AUG 9 2015
.SYNOPSIS...
ANOTHER NICE DAY IS EXPECTED ACROSS THE NORTH COUNTRY
WITH MAINLY DRY CONDITIONS AND NEAR NORMAL TEMPERATURES. AN ISOLATED
SHOWER OR SPRINKLE IS POSSIBLE ACROSS NORTHEAST VERMONT THIS
AFTERNOON. OTHERWISE...DRY CONDITIONS WITH SLIGHTLY ABOVE NORMAL
TEMPERATURES ARE FORECASTED FOR MONDAY...BEFORE SHOWERS ARRIVE ON
MONDAY NIGHT INTO TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 711 AM EDT SUNDAY...VERY MINOR CHANGES TO CRNT FCST THAT
INCLUDED ADJUSTING FOR LATEST SATL TRENDS AND PLACE THE LATEST OBS
INTO THE GRIDS. DEEPER MOISTURE ASSOCIATED WITH 5H VORT CONTS TO
MOVE ACROSS CENTRAL/EASTERN VT THIS MORNING....WITH WATER VAPOR
SHOWING LARGE SCALE AREA OF SUBSIDENCE DEVELOPING OVER NORTHERN
NY. THIS WILL RESULT IN MOSTLY SUNNY SKIES TODAY AND LIMIT OVERALL
COVERAGE OF ANY POTENTIAL SHOWERS. HIGHS WILL WARM INTO THE 70S TO
NEAR 80 MOST LOCATIONS WITH LIGHT NORTH WINDS.
FORECAST FOCUS TODAY WILL BE CHANCE FOR AN ISOLATED SHOWER ACROSS
THE NORTHEAST KINGDOM OF VT. CRNT WATER VAPOR SHOWS MID/UPPER LVL
TROF CONTS...WITH WEAK S/W ENERGY DIVING SOUTH FROM EASTERN
CANADA. ALSO...WATER VAPOR SHOWS VERY DRY AIR AHEAD OF THIS
SYSTEM...SO ANY PRECIP CHCS TODAY WILL BE VERY ISOLATED AND
CONFINED TO THE NORTHEAST KINGDOM OR MTNS OF NORTHERN VT. BTV 4KM
IS MOST AGGRESSIVE WITH SHOWING QPF AND ASSOCIATED COMPOSITE
REFLECTIVITY RETURNS ACROSS MOST OF THE HIGHER TRRN OF VT THIS
AFTN...BUT GIVEN PROGGED SOUNDING MOISTURE PROFILES...THINKING
THIS IS OVERDONE. WL USE A BLEND OF NAM/GFS AND HRRR TO MENTION
SCHC WITH A SMALL AREA OF CHC POPS ACROSS ESSEX COUNTY VT. REST OF
CWA WILL REMAIN DRY. TEMPS WILL BE SEVERAL DEGREES WARMER THAN
YESTERDAY WITH HIGHS GENERALLY IN THE 70S TO NEAR 80F.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
AS OF 345 AM EDT SUNDAY...OUR NICE PERIOD OF DRY
WEATHER WILL BE COMING TO AN END BY TUESDAY...AS MID/UPPER LVL TROF
AND ASSOCIATED SFC LOW PRES IMPACT THE NE CONUS. FOR MONDAY...BEST
850 TO 500MB MOISTURE IS WEST OF OUR CWA THRU 00Z..ALONG WITH
FORCING ASSOCIATED WITH INITIAL 5H VORT. WILL CONT TO MENTION CHC
POPS TWD 00Z TUESDAY ACROSS THE SLV AND WESTERN DACKS. PROGGED 85H
TEMPS WARM BTWN 12-14C BY 18Z MONDAY...SUPPORTING M/U 70S MTN TOWNS
TO L/M 80S WARMER VALLEYS.
OVERALL...NAM/GFS AND ECMWF HAVE COME INTO PRETTY GOOD AGREEMENT
WITH HANDLING THE DEEPENING OF MID/UPPER LVL TROF ACROSS THE GREAT
LAKES AND SFC LOW PRES TRACKING FROM THE OHIO VALLEY MONDAY NIGHT
INTO THE SLV BY TUES. IN ADDITION...MODELS HAVE TRENDED SEVERAL
HOURS SLOWER WITH THE PRECIP ARRIVE ON MONDAY NIGHT INTO TUESDAY
ACROSS OUR CWA...WITH HEAVIEST QPF AXIS OF UP TO 1.0 OF RAIN
EXPECTED OVER NORTHERN NY BY TUES AFTN. LOW LEVEL FORCING/ ADVECTION
OF MOISTURE IS IMPRESSIVE ASSOCIATED WITH NOSE OF 85H JET OF 45 TO
50 KNOTS IMPACTING OUR CWA BY 12Z TUESDAY. GFS/NAM SHOW A STRONG
BAND OF 850 TO 700MB FGEN FORCING...ALONG WITH GOOD LVLL MOISTURE
CONVERGENCE LIFTING FROM SW TO NE ACRS OUR CWA BTWN 09Z AND 18Z
TUESDAY.
HAVE NOTED SOME HIGHER RESOLUTION MODELS SHOWING IMPACTS OF
SE TO SOUTHWEST WINDS ON THE ASSOCIATED QPF FIELDS WITH SOME
SHADOWING OVER THE CPV AND PARTS OF THE NEK. GIVEN THE MOISTURE FEED
WITH PWS AROUND 1.50" AND GOOD UPPER LEVEL DYNAMICS WITH APPROACHING
TROF AND HEIGHT FALLS...A WIDESPREAD RAINFALL IS VERY LIKELY LATE
MONDAY NIGHT INTO TUESDAY. WILL CONT THE TREND AND MENTION CAT POPS
ACRS OUR CWA...BUT TRRN WILL INFLUENCE QPF FIELDS....WITH HIGHEST
VALUES OF UP TO 1.0 OCCURRING ACRS THE NORTHERN NY/HIGH PEAKS
REGION...GIVEN THE LLVL JET ORIENTATION. MEANWHILE...VALUES ACROSS
VT WILL RANGE FROM 0.25 TO 0.75" WITH HIGHEST AMOUNTS ON SE UPSLOPE
AREAS OF THE GREEN MTNS.
SOUNDINGS SHOW RIDGETOP WINDS BTWN 45 AND 50 KNOTS ON TUESDAY
MORNING...BUT INVERSION LEVEL IS AROUND 2000 FT....SUPPORTING
MIXED LAYER WINDS TO THE SURFACE UP TO 35 MPH OR SO ALONG THE
WESTERN SLOPES AND HIGHER TRRN. TEMPS TUES WILL BE TRICKY WITH
1000 TO 500MB THICKNESS RIDGE OVERHEAD...BUT LOTS OF CLOUDS AND
PRECIP AROUND. THINKING A FEW BREAKS WILL DEVELOP IN MID LVL DRY
SLOT OVER THE SLV/WESTERN DACKS AND THIS AREA WILL REACH
80F...WHILE MOST OF THE OTHER SITES STAY IN THE M/U 60S MTNS TO
L/M 70S CPV/SOUTHERN VT.
A RUMBLE OF THUNDER ASSOCIATED WITH THE DYNAMICS CANNOT BE RULED
OUT ON TUESDAY MORNING...WITH ANOTHER CHC OF A RUMBLE ON TUES AFTN
IN THE WARM SECTOR OVER SLV. ALSO...NOTED WEAK ELEVATED
INSTABILITY LAYER WITH ML CAPE VALUES AROUND 400 J/KG ON MONDAY
NIGHT/TUESDAY MORNING...ASSOCIATED WITH NOSE OF 85H JET AND STRONG
LLVL WAA.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 354 AM EDT SUNDAY...RATHER ACTIVE WEATHER WITH CHANCE OF
SHOWERS FOR MUCH OF THE PERIOD AS UPPER LEVEL TROUGH REMAINS OVER
THE EAST.
WEAK SURFACE BOUNDARY WILL MOVE SLOWLY EAST OF THE AREA TUESDAY
NIGHT...WITH HIGHEST PRECIPITABLE WATER VALUES SHIFTING TO THE EAST
AS WELL. UPPER LEVEL LOW LAGS BEHIND HOWEVER...SO WHILE HIGHEST
CHANCE OF SHOWERS WILL BE DURING THE EVENING...THERE WILL BE A
CONTINUED CHANCE FOR A FEW SHOWERS DURING THE OVERNIGHT AS WELL.
WITH UPPER LEVEL LOW AND ASSOCIATED COLD POOL ALOFT STILL OVER THE
REGION ON WEDNESDAY...WE CAN EXPECT MORE CLOUDS AND A CONTINUED
CHANCE OF SHOWERS. WEST TO NORTHWEST UPSLOPE FLOW WILL HELP PROVIDE
SOURCE OF LIFT FOR BETTER COVERAGE OVER THE HIGHER TERRAIN. LIMITED
INSTABILITY...BUT AN ISOLATED THUNDERSTORM ALSO POSSIBLE.
UPPER TROUGH SLOW TO DEPART THURSDAY...SO STILL CHANCE OF A FEW
SHOWERS. DRIER CONDITIONS LATER THURSDAY INTO FRIDAY MORNING WITH
SHORTWAVE RIDGING ALOFT AT 500MB. FROM FRIDAY ONWARD YET ANOTHER
UPPER LEVEL TROUGH WILL APPROACH FROM THE NORTHERN GREAT LAKES
REGION AND RE-ESTABLISH THE EASTERN US TROUGH AND A CHANCE FOR MORE
SHOWERS AND A FEW WIDELY SCATTERED STORMS.
AS FOR TEMPS...MAX TEMPS WILL AVERAGE SEVERAL DEGREES BELOW NORMAL
WITH HIGHS MAINLY IN THE 70S...PERHAPS AROUND 80 IN SPOTS FRIDAY AND
SATURDAY. MINS WILL BE IN THE 50S TO AROUND 60...GENERALLY WITHIN
A FEW DEGREES OF NORMAL FOR MID AUGUST.
&&
.AVIATION /11Z SUNDAY THROUGH THURSDAY/...
THROUGH 06Z MONDAY...MAINLY VFR EXPECTED...WITH THE EXCEPTION OF
SOME IFR/LIFR FOG/BR LATE TONIGHT AND EARLY SUNDAY MORNING AT
SLK/MSS/MPV. BKN HIGH CIRRUS DECK WILL PROGRESS EASTWARD
OVERNIGHT...SLOWLY CLEARING THE REGION BETWEEN THROUGH 11Z. WITH
THE CLEARING WILL COME THE POTENTIAL FOR FOG/BR DEVELOPMENT.
GREATEST LIKELIHOOD TO SEE LIFR FOG WILL BE AT SLK & MPV...WITH
THE POSSIBILITY AT MSS AS WELL. FOG/BR LIFTS BY AROUND 12Z WITH
CLEAR SKIES GIVING WAY TO A DEVELOPING CU FIELD IN THE
AFTERNOON...WITH ALL SITES VFR. WINDS LIGHT AND LOCALLY VARIABLE
OVERNIGHT (EXCEPT SE AT RUT WITH DRAINAGE WIND) BECOME GENERALLY
NORTHERLY FROM 4-7 KNOTS ON SUNDAY...BUT WITH LIGHT FLOW...THEY
WILL BE LOCALLY VARIABLE.
OUTLOOK 06Z MONDAY THROUGH THURSDAY...
06Z MONDAY THROUGH 00Z TUESDAY...VFR EXCEPT LOCAL IFR WITH OVERNIGHT
PATCHY FOG MAINLY MPV AND SLK.
00Z TUESDAY THROUGH 00Z WEDNESDAY...DETERIORATING CONDITIONS
LIKELY (MVFR POSSIBLE IFR) WITH PERIODS OF RAIN SHOWERS AND
STRATUS.
00Z WEDNESDAY ONWARD...VFR WITH PERIODS OF MVFR IN LINGERING
SCATTERED SHOWERS. SHOWERS DIMINISHING THURSDAY.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...TABER
NEAR TERM...TABER
SHORT TERM...TABER
LONG TERM...RJS
AVIATION...RJS/MUCCILLI
AREA FORECAST DISCUSSION
NWS RALEIGH NC
945 AM EDT SUN AUG 9 2015
.SYNOPSIS...WEAK HIGH PRESSURE WILL EXTEND INTO THE REGION THROUGH
TONIGHT. A WARM FRONT WILL LIFT NORTH ACROSS THE AREA ON MONDAY. A
COLD FRONT WILL SWEEP THROUGH THE REGION TUESDAY AND TUESDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 945 AM SUNDAY...
BAND OF LIGHT SHOWERS ORIENTED NNW TO SSE WHICH DROPPED SSE THROUGH
THE NRN PIEDMONT EARLIER THIS MORNING HAS PUSHED INTO THE SANDHILLS
WHILE DIMINISHING IN COVERAGE. THE SUBTLE FORCING DRIVING THIS
FEATURE INCLUDING WEAK LOW LEVEL MASS CONVERGENCE ALONG THE LEADING
EDGE OF AN 850 MB MOISTURE BOUNDARY APPEARS TO BE DWINDLING... AND
WITH THE DEPARTURE OF A WEAKENING MID LEVEL WAVE/MCV BY AFTERNOON...
THIS SHOULD CONTINUE TO FALL APART SLOWLY. MODELS SHOW MOUNTAIN
CONVECTION FORMING THIS AFTERNOON... AND THE MEAN FLOW PATTERN WOULD
SUPPORT SOME OF THIS ACTIVITY SLIPPING SE INTO THE FAR WRN PIEDMONT
AFTER SUNSET... SO WILL RETAIN LOW CHANCE POPS LATER TONIGHT. PATCHY
MOISTURE IS EXPECTED TO PERSIST AT 700 MB WITH WEAK FLOW... SO
EXPECT GENERALLY PARTLY CLOUDY SKIES AREAWIDE TODAY ESPECIALLY AS WE
APPROACH PEAK MIXING... WITH SHORTER PERIODS OF MOSTLY CLOUDY SKIES.
OBSERVED TRENDS AND HI-RES GUIDANCE SUPPORT HIGHS OF 85-90...
ASSUMING ENOUGH BREAKS IN THE CLOUDS FOR SUFFICIENT INSOLATION. -GIH
EARLIER DISCUSSION FROM 250 AM: LATEST SURFACE ANALYSIS SHOWS WEAK
HIGH PRESSURE CENTERED OVER THE MID ATLANTIC REGION AS LOW PRESSURE
OFF THE VA COAST MOVES AWAY FROM THE REGION. SATELLITE IMAGERY SHOWS
A REGION OF SCT TO MOSTLY BKN LOW/MID CLOUDS FROM CENTRAL PA
SOUTHWARD TO WESTERN NC. THESE CLOUDS HAVE BEEN EXPANDING SOUTHWARD
AND ARE ASSOCIATED WITH A REGION OF ENHANCED MOISTURE AND WEAK
ISENTROPIC UPGLIDE ABOUT THE 305K SURFACE. REGIONAL RADAR SHOWS A
FEW SHOWERS JUST NORTH OF THE TRIAD IN FAR NORTHERN NC AND
SOUTHWESTERN VA. EARLIER RUNS OF THE HRRR INDICATED THESE SHOWERS
COULD PUSH SOUTHEAST TOWARD THE TRIANGLE AREA BUT THE LAST RUN OR
TWO HAVE BACKED OFF THIS SCENARIO. WILL INCLUDE A SLIGHT CHANCE OF A
SHOWER FOR A SMALL AREA IN THE TRIAD FOR THE NEXT FEW HOURS AS THESE
SPRINKLES/SHOWERS MOVE SOUTHEAST AND LIKELY DISSIPATE.
THE REMAINDER OF TODAY SHOULD FEATURE FAIR WEATHER WITH PARTLY
CLOUDY SKIES FEATURING MULTIPLE CLOUD LAYERS. LITTLE FORCING FOR
ASCENT AND PRECIPITATION IS AVAILABLE ACROSS CENTRAL NC. ISOLATED TO
SCATTERED THUNDERSTORMS WILL DEVELOP ACROSS THE NC MOUNTAINS THIS
AFTERNOON. A FEW OF THESE STORMS COULD PUSH OFF THE MOUNTAINS AND
APPROACH THE TRIAD AREA TOWARD DINNER TIME BUT GIVEN THE LIMITED
COVERAGE AND STABLE AIRMASS ACROSS THE TRIAD...WILL NOT INCLUDE ANY
STORMS FOR THIS AFTERNOON OR EARLY EVENING. SCT CONVECTION THAT
DEVELOPS FURTHER UPSTREAM ACROSS THE OH VALLEY AND THE MID ATLANTIC
THIS AFTERNOON MAY HAVE SUFFICIENT SUPPORT TO ALLOW A SHOWER OR
STORM MOVE INTO THE NORTHWEST PIEDMONT VERY LATE IN THE EVENING.
THIS SCENARIO IS SUPPORTED BY A FEW OF THE CONVECTION ALLOWING
MODELS INCLUDING THE NCAR ENSEMBLE. SO WILL INCLUDE A SLIGHT CHC POP
FOR THIS AREA TO COVER THE POTENTIAL. OTHERWISE...FAIR WEATHER AND
DRY CONDITIONS ARE EXPECTED TODAY AND TONIGHT. THICKNESSES VALUES
AND STATISTICAL GUIDANCE HAVE TRENDED A LITTLE COOLER FOR TODAYS
HIGHS WHICH SHOULD RANGE BETWEEN 86 AND 90. LOWS TONIGHT WILL RANGE
BETWEEN 66-72. LIGHT AND VARIABLE WINDS WILL BECOME LIGHT
SOUTHEASTERLY AND SOUTHERLY ACROSS THE WESTERN PIEDMONT TODAY AND
BECOME LIGHT NORTHEAST AND EASTERLY EAST OF THE RIDGE AXIS ACROSS
THE EASTERN PIEDMONT AND COASTAL PLAIN. -BLAES
&&
.SHORT TERM /MONDAY AND MONDAY NIGHT/...
AS OF 312 AM SUNDAY...
A NORTHWEST FLOW ALOFT ACROSS CENTRAL NC EARLY MONDAY BECOMES MORE
WESTERLY AND SLIGHTLY SOUTHWESTERLY BY MONDAY NIGHT AS UPPER LEVEL
TROUGHING AND THE ASSOCIATED HEIGHT FALLS MOVE INTO THE GREAT LAKES
REGION. AT THE SURFACE...A WARM FRONT WILL LIFT NORTH ACROSS NC
EARLY MONDAY WITH AN APPROACHING COLD FRONT REACHING THE WESTERN
APPALACHIANS TOWARD DAYBREAK TUESDAY. CHANCES FOR SHOWERS AND
THUNDERSTORMS GRADUALLY INCREASE DURING THE PERIOD FROM WEST TO
EAST. WITH THE BEST FORCING REMAINING NORTH OF OUR REGION AND
INDICATIONS OF LIMITED INSTABILITY AND MEAGER MID LEVEL LAPSE
RATES...HAVE CUT BACK ON POPS A BIT. NEW SPC DAY 2 OUTLOOK KEEPS THE
MARGINAL SEVERE WEATHER THREAT WEST OF OUR AREA...MAINLY OWING TO
THE LIMITED INSTABILITY IN OUR FORECAST AREA. DESPITE A WARMING
ATMOSPHERE AND INCREASING THICKNESS VALUES...CLOUDS SHOULD HOLD
HIGHS BACK SLIGHTLY ON MONDAY...HIGH SHOULD RANGE BETWEEN 86 AND 92.
LOWS MONDAY NIGHT WILL BE MODERATED BY THE CLOUD COVER AND RANGE
BETWEEN 69 AND 74 DEGREES. -BLAES
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 310 AM SUNDAY...
FOR THE PERIOD TUESDAY THROUGH WEDNESDAY...DIFFERENCES BETWEEN THE
GFS AND THE NAM FOR TUESDAY INTO TUESDAY NIGHT MAKE THIS FORECAST OF
SOMEWHAT LOWER CONFIDENCE...AS THE GFS BY EARLY TUESDAY FORECASTS A
DRY SLOT MOVING INTO CENTRAL NORTH CAROLINA REALLY REDUCING
PRECIPITATION CHANCES FOR THE MORNING INTO THE EARLY AFTERNOON...
WHILE THE NAM IS MUCH MORE MOIST TO START THE DAY...AND THROUGHOUT
THE DAY TOWARD INTERSTATE 95. THE GFS MAY BE ON TO SOMETHING TO
START THE DAY...BUT FOR THE AFTERNOON THINK SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS SHOULD BEGIN TO OCCUR. CONSENSUS OF THE
NAM AND GFS MODELS IS THAT AT LEAST MODEST LIFT SHOULD BE IN PLACE
AS THE SURFACE FRONT APPROACHES...WITH GOOD UPPER DIVERGENCE BY THE
AFTERNOON. K INDICES AND 850MB THETA-E VALUES ARE HIGH...AND MLCAPE
THROUGH THE LOWEST KM OR SO IS ON THE ORDER OF 1000J/KG ON THE
GFS...TO ABOUT 1500J/KG ON THE NAM. THE NAM TENDS TO BE SLOWER AND
FARTHER WEST WHILE THE GFS CERTAINLY CONCENTRATES ITS HIGHER VALUES
OF INSTABILITY AND LIFT ALONG AND EAST OF U.S. 1. WILL TEND TO LOWER
CHANCES FOR SHOWERS FOR TUESDAY MORNING...RETAINING THE LIKELY
CHANCES FOR SHOWERS AND THUNDERSTORMS FOR THE MID-AFTERNOON ON ALONG
AND EAST OF U.S. 1 AND CONTINUING INTO THE EVENING FOR MUCH OF THAT
AREA. IF THE GFS BUFR SOUNDINGS ARE CORRECT...PRECIPITATION COULD
END EARLIER...BUT THE PREVIOUS FORECAST CAPTURED A GOOD BLEND OF THE
NAM AND GFS WITH A SLIGHT CHANCE OF SHOWERS LINGERING IN THE FAR
EAST INTO EARLY WEDNESDAY MORNING.
BOTH THE NAM AND GFS FORECAST MODEST 0-3KM SHEAR AT BEST...AND WIND
FIELDS ARE NOT THAT STRONG DESPITE THE FRONT WITH THE 250MB RIGHT
ENTRANCE REGION OF THE JET NORTH IN VIRGINIA. 850MB WINDS TO AROUND
20KT OR SO...AND THE MID- AND UPPER-LEVEL JETS BEING NORTH...SUGGEST
LIMITED FORCING ALOFT. HOWEVER...IF THE GFS BUFR SOUNDINGS ARE
CORRECT...THERE IS AN INVERTED-V PROFILE THAT COULD RESULT IN
INSTANCES OF STRONG WIND GUSTS. THINK THAT THERE IS THE POTENTIAL
FOR ISOLATED SEVERE STORMS TUESDAY AFTERNOON INTO THE EVENING...
MAINLY ALONG AND EAST OF U.S. 1 WHERE THE MORE FAVORABLE PARAMETERS
SHOULD EXIST PARTICULARLY IF ONE LEANS TOWARD THE GFS. PLAN TO LEAN
MORE TOWARD THE GFS MOS GUIDANCE TEMPERATURES FOR TUESDAY...AROUND
90 FOR MUCH OF CENTRAL NORTH CAROLINA WITH HEAT INDICES JUST ABOVE
100 SOUTHEAST.
WEDNESDAY...GFS BUFR SOUNDINGS DRY AND AFTER ANY EARLY MORNING
ISOLATED SHOWER TOWARD KGSB AND KCTZ BUFR SOUNDINGS WOULD SUGGEST
LOW CHANCES FOR ANY DEEP CONVECTION...WITH POSSIBLY SOME HIGH-BASED
CU. DEW POINTS SHOULD BE NOTICEABLY LOWER OR BECOME NOTICEABLY LOWER
ACROSS THE AREA. ACCOMPANIED BY A NORTH TO NORTHEAST LOW-LEVEL
FLOW...HIGH TEMPERATURES MAINLY 85 TO 90.
FOR THE PERIOD WEDNESDAY NIGHT THROUGH SATURDAY...THE UPPER-AIR
PATTERN FEATURES A PERSISTENT RIDGE AXIS FROM THE SOUTHERN PLAINS
AND FOUR CORNERS NORTH ALONG THE ROCKIES AND INTO THE PLAINS OF
CANADA...WHILE BROAD TROUGHINESS EXISTS OVER THE EASTERN THIRD OF
THE CONUS. THE COLD FRONT SHOULD BE SOUTH OF CENTRAL NORTH CAROLINA
WEDNESDAY INTO WEDNESDAY NIGHT...CONTINUING TO GRADUALLY MOVE SOUTH
AS HIGH PRESSURE BUILDS IN FROM THE NORTH. WEAK PIEDMONT SURFACE
TROUGHING RETURNS BY SATURDAY. THE ECMWF AND THE GFS TO SOME DEGREE
FEATURE A WEAK SURFACE WAVE DEVELOPING ALONG THE FRONT WHICH MAY
SLOW ITS PROGRESS OR RESULT IN SOME LINGERING MOISTURE NEAR THE
COASTAL PLAIN OVERNIGHT WEDNESDAY...BUT FOR THIS FORECAST WILL
MAINTAIN CONSISTENCY AND LEAVE THE FORECAST DRY OVERNIGHT ALONG AND
EAST OF INTERSTATE 95 AS THE MEAN DRY AIR ON THE GFS IS QUITE
NOTICEABLE. ON THURSDAY AFTERNOON...WITH THE SURFACE FRONT JUST TO
THE SOUTH...A VERY ISOLATED SHOWER COULD OCCUR MAINLY SOUTH OF A
LINE FROM KMEB TO KCTZ...BUT AGAIN AT THIS STAGE LEAVING THE
FORECAST DRY AND MAINTAINING CONSISTENCY SEEMS A WISE APPROACH. AT
THE END OF THE WEEK...THE GFS IN PARTICULAR...WITH WEAKNESS IN
HEIGHTS ALOFT...FORECASTS SOME DEEP CONVECTION IN VICINITY OF THE
MOUNTAINS...AND SOME QPF TRIES TO GRAZE THE FAR WESTERN PIEDMONT
ESPECIALLY LATE FRIDAY. HOWEVER...THE STEERING FLOW SEEMS QUITE WEAK
AND THICKNESS PROFILES WOULD SUGGEST FOR NOW THE EASTWARD PROGRESS
OF SUCH CONVECTION SHOULD REMAIN WEST OF CENTRAL NORTH CAROLINA.
OVERALL...WITH ALL OF THIS SAID...THIS FORECAST WILL CONTINUE TO BE
DRY FOR CENTRAL NORTH CAROLINA WEDNESDAY NIGHT THROUGH SATURDAY.
TEMPERATURES SHOULD AVERAGE ABOUT A CATEGORY BELOW NORMAL BEHIND THE
COLD FRONT BY THURSDAY...GRADUALLY RECOVERING TO AT OR ABOVE NORMAL
BY SATURDAY USING A COMBINATION OF 1000-850MB THICKNESSES WHICH ARE
QUITE WARM...AND MOS GUIDANCE CONSENSUS.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AS OF 705 AM SUNDAY...
VFR CONDITIONS ARE EXPECTED TO DOMINATE ACROSS CENTRAL NC DURING THE
NEXT 24 HOURS. AN UPPER LEVEL DISTURBANCE WAS PRODUCING AN AREA OF
SCT-BKN CLOUDS WITH VFR BASES OF 6-8KFT ACROSS THE PIEDMONT
AREA THIS MORNING. THESE CLOUDS WILL CONTINUE TO IMPACT THE
TERMINALS AT KINT/KGSO/KRDU THROUGH MID MORNING. RADAR AND SURFACE
OBSERVATIONS WERE INDICATING A FEW SHOWERS BETWEEN THE TRIAD AND
TRIANGLE IMPACTING KBUY AND KSCR THAT WERE SHIFTING EAST. A LOWERING
OF THE CLOUD DECK AND A BRIEF MVFR VSBY RESTRICTION IN A LIGHT RAIN
SHOWER CAN BE EXPECTED. WILL OMIT ANY MENTION IN THE TAFS AS THIS
FEATURE SHOULD DIMINISH BY THE TIME IT WOULD APPROACH KRDU. A FEW
THUNDERSTORMS MAY DEVELOP ACROSS THE
BLUE RIDGE THIS AFTERNOON AND DRIFT INTO THE WESTERN PIEDMONT DURING
THE EARLY EVENING. COVERAGE OF THESE STORMS SHOULD BE LIMITED AND
CONFIDENCE THAT THEY WILL MAKE IT TO THE KINT/KGSO TERMINALS IS VERY
SMALL SO WILL NOT INCLUDE IT IN THE TERMINALS.
OTHERWISE...LOOK FOR MAINLY SCT TO OCCASIONALLY BKN CLOUDS AT 5-8KFT
TODAY WITH PERIODS OF BKN MID AND HIGH CLOUDS. LIGHT AND VARIABLE
WINDS THIS MORNING WILL BECOME LIGHT SOUTHWEST IN THE WESTERN
PIEDMONT (KINT/KGSO)AND LIGHT NORTHEASTERLY IN THE EASTERN PIEDMONT
AND COASTAL PLAIN TERMINALS (KRDU/KRWI/KFAY).
LOOKING FURTHER AHEAD... A TREND FOR MORE ACTIVE WEATHER AND
POTENTIAL ADVERSE AVIATION CONDITIONS WITH SCT CONVECTION RETURNS ON
MONDAY AND INCREASES FOR MONDAY NIGHT AND TUESDAY/TUESDAY NIGHT AS A
COLD FRONT MOVES THROUGH THE AREA. FAIR WEATHER SHOULD RETURN ON
WEDNESDAY AND PERSIST INTO THURSDAY. -BLAES
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLAES
NEAR TERM...HARTFIELD/BLAES
SHORT TERM...BLAES
LONG TERM...DJF
AVIATION...BLAES
AREA FORECAST DISCUSSION
NWS BISMARCK ND
903 AM CDT SUN AUG 9 2015
.UPDATE...
ISSUED AT 900 AM CDT SUN AUG 9 2015
LATEST WATER VAPOR WITH RAP13 UPPER HEIGHTS OVERLAID ACCURATELY
PORTRAY A MID/UPPER LOW CIRCULATION OVER SOUTHEAST MONTANA WITH A
COUPLE OF SHORTWAVES ROTATING AROUND THE LOW INTO SOUTHWEST NORTH
DAKOTA. BOWMAN RADAR CONTINUES TO SHOW INCREASING RAIN SHOWER
COVERAGE SOUTHWEST...WITH BISMARCK RADAR INDICATING ISOLATED TO
SCATTERED SHOWERS IN SOUTH CENTRAL NORTH DAKOTA AND INTO THE
SOUTHERN JAMES RIVER VALLEY. FOR THIS UPDATE...BLENDED IN CURRENT
FORECAST WITH THE LATEST HRRR AND ADJUSTED THOSE POPS BASED ON
CURRENT RADAR TRENDS AND SURFACE OBSERVATIONS.
OVERALL...MODEL CONSENSUS AND FORECAST OVERALL REMAINS NEARLY
UNCHANGED WITH ISOLATED TO SCATTERED SHOWERS MAINLY ALONG AND
SOUTH OF I-94 REST OF THIS MORNING. FOR THE AFTERNOON...SCATTERED
SHOWERS AND THUNDERSTORMS DEVELOPING A BIT FARTHER NORTH AS THE
MID/UPPER LOW SLIDES INTO NORTHWEST SOUTH DAKOTA.
UPDATE ISSUED AT 643 AM CDT SUN AUG 9 2015
LOWERED SHORT TERM POPS SLIGHTLY ACROSS THE SOUTHWEST BASED ON
LATEST RADAR IMAGERY. CURRENTLY SEEING A SLIGHT LULL IN SHOWERS
ACROSS SOUTHWEST. HOWEVER...WV IMAGERY SHOWS WEAK DISTURBANCE IN
CYCLONIC FLOW OVER SOUTHEASTERN MONTANA THAT IS APPROACHING OUR
CWA. IR IMAGERY SHOWS COOLER CLOUD TOPS APPROACHING OUR SOUTHWEST AND
LAST FEW SCANS FROM BOWMAN RADAR SHOW ECHOES DEVELOPING AGAIN OVER
THE SAME AREA. OTHERWISE...BLENDED OTHER FORECAST ELEMENTS TO
LATEST OBS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM CDT SUN AUG 9 2015
THE MAIN FOCUS TODAY IS ON SHOWERS AND THUNDERSTORMS ALONG AND
SOUTH OF U.S. HIGHWAY 2.
SO FAR THIS MORNING...THE 00 UTC NAM ARW/NAM NMM AND THE LAST FEW
RUNS OF THE HRRR HAVE A GOOD HANDLE ON SHOWERS INITIATING IN
SOUTHWEST AND SOUTH CENTRAL NORTH DAKOTA AS ONGOING CONVECTION
SHIFTS INTO NORTHEASTERN SOUTH DAKOTA.
THUS FAR...THUNDERSTORMS HAVE BEEN CONFINED TO SOUTH DAKOTA...BUT
THAT SHOULD CHANGE AROUND NOON AS SOLAR HEATING HELPS
DESTABILIZATION BENEATH THE MID LEVEL LOW OVER EASTERN MONTANA IN
08 UTC WATER VAPOR IMAGERY. BASED ON HIRES MODELS...AND VALIDATED
BY THE STORM PREDICTION CENTER CONVECTIVE OUTLOOKS...THE SEVERE
THREAT IS LOW.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 334 AM CDT SUN AUG 9 2015
MODELS ARE IN GOOD AGREEMENT BUILDING STRONG UPPER LEVEL RIDGE
ACROSS THE WEST EARLY IN THE WEEK WITH THE RIDGE AXIS SLOWLY
MOVING EAST. DRY WEATHER EXPECTED THROUGH MOST OF THE WEEK WITH
TEMPERATURES BUILDING TO MUCH ABOVE NORMAL BY MID-WEEK...UPPER
90S POSSIBLE WEST BY WEDNESDAY. SOME MODEL DIFFERENCES DEVELOP BY
LATE WEEK AS STRONG UPPER LEVEL LOW MOVES INTO THE PAC NW WITH THE
UPPER LEVEL RIDGE AXIS SHIFTING EAST OF THE NORTHERN PLAINS BY
EARLY WEEKEND. MAX TEMPS MODERATE BY LATE WEEK...STILL ABOVE
NORMAL IN THE UPPER 80S...WITH INCREASING CHANCES OF
SHOWERS/THUNDERSTORMS INTO THE WEEKEND AS UPPER LEVEL RIDGE BREAKS
DOWN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 643 AM CDT SUN AUG 9 2015
THE MAIN HAZARD TO AVIATION WILL BE POSSIBLE MVFR CONDITIONS IN
SHOWERS AND THUNDERSTORMS AT KDIK/KBIS/KJMS TODAY. TIMING INDICATED
IN TAFS IS LOW TO AVERAGE CONFIDENCE. OTHERWISE CONDITIONS WILL
REMAIN VFR.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...SCHECK
LONG TERM...JNS
AVIATION...SCHECK
AREA FORECAST DISCUSSION
NWS BISMARCK ND
643 AM CDT SUN AUG 9 2015
.UPDATE...
ISSUED AT 643 AM CDT SUN AUG 9 2015
LOWERED SHORT TERM POPS SLIGHTLY ACROSS THE SOUTHWEST BASED ON
LATEST RADAR IMAGERY. CURRENTLY SEEING A SLIGHT LULL IN SHOWERS
ACROSS SOUTHWEST. HOWEVER...WV IMAGERY SHOWS WEAK DISTURBANCE IN
CYCLONIC FLOW OVER SOUTHEASTERN MONTANA THAT IS APPROACHING OUR
CWA. IR IMAGERY SHOWS COOLER CLOUD TOPS APPROACHING OUR SOUTHWEST AND
LAST FEW SCANS FROM BOWMAN RADAR SHOW ECHOES DEVELOPING AGAIN OVER
THE SAME AREA. OTHERWISE...BLENDED OTHER FORECAST ELEMENTS TO
LATEST OBS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM CDT SUN AUG 9 2015
THE MAIN FOCUS TODAY IS ON SHOWERS AND THUNDERSTORMS ALONG AND
SOUTH OF U.S. HIGHWAY 2.
SO FAR THIS MORNING...THE 00 UTC NAM ARW/NAM NMM AND THE LAST FEW
RUNS OF THE HRRR HAVE A GOOD HANDLE ON SHOWERS INITIATING IN
SOUTHWEST AND SOUTH CENTRAL NORTH DAKOTA AS ONGOING CONVECTION
SHIFTS INTO NORTHEASTERN SOUTH DAKOTA.
THUS FAR...THUNDERSTORMS HAVE BEEN CONFINED TO SOUTH DAKOTA...BUT
THAT SHOULD CHANGE AROUND NOON AS SOLAR HEATING HELPS
DESTABILIZATION BENEATH THE MID LEVEL LOW OVER EASTERN MONTANA IN
08 UTC WATER VAPOR IMAGERY. BASED ON HIRES MODELS...AND VALIDATED
BY THE STORM PREDICTION CENTER CONVECTIVE OUTLOOKS...THE SEVERE
THREAT IS LOW.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 334 AM CDT SUN AUG 9 2015
MODELS ARE IN GOOD AGREEMENT BUILDING STRONG UPPER LEVEL RIDGE
ACROSS THE WEST EARLY IN THE WEEK WITH THE RIDGE AXIS SLOWLY
MOVING EAST. DRY WEATHER EXPECTED THROUGH MOST OF THE WEEK WITH
TEMPERATURES BUILDING TO MUCH ABOVE NORMAL BY MID-WEEK...UPPER
90S POSSIBLE WEST BY WEDNESDAY. SOME MODEL DIFFERENCES DEVELOP BY
LATE WEEK AS STRONG UPPER LEVEL LOW MOVES INTO THE PAC NW WITH THE
UPPER LEVEL RIDGE AXIS SHIFTING EAST OF THE NORTHERN PLAINS BY
EARLY WEEKEND. MAX TEMPS MODERATE BY LATE WEEK...STILL ABOVE
NORMAL IN THE UPPER 80S...WITH INCREASING CHANCES OF
SHOWERS/THUNDERSTORMS INTO THE WEEKEND AS UPPER LEVEL RIDGE BREAKS
DOWN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 643 AM CDT SUN AUG 9 2015
THE MAIN HAZARD TO AVIATION WILL BE POSSIBLE MVFR CONDITIONS IN
SHOWERS AND THUNDERSTORMS AT KDIK/KBIS/KJMS TODAY. TIMING INDICATED
IN TAFS IS LOW TO AVERAGE CONFIDENCE. OTHERWISE CONDITIONS WILL
REMAIN VFR.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JNS
SHORT TERM...SCHECK
LONG TERM...JNS
AVIATION...SCHECK
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1047 AM EDT SUN AUG 9 2015
.SYNOPSIS...
WEAK FLOW CONTINUES TODAY. LOW PRESSURE SYSTEM PASSES
NORTH MONDAY INTO MONDAY NIGHT. MID/UPPER LEVEL TROF AXIS CROSSES
TUESDAY. DRIER AIR WITH COOLER NIGHTS WEDNESDAY AND THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
1030 AM UPDATE. NO SIGNIFICANT CHANGES.
PREVIOUS DISCUSSION...
ANOTHER EARLY MORNING WITH AREAS OF CLOUDS VERSUS VALLEY FOG IN THE
WEAK DOG DAY WIND FLOW. A FEW SHOWERS REDEVELOPED OVER THE CENTRAL
WV MOUNTAINS BETWEEN 06Z AND 08Z PROBABLY AIDED BY A WEAK MID LEVEL
VORT MAX INDICATED ON RAP SOLUTION. BY 10Z FIGURING ANY SURVIVING
SHOWER WOULD BE IN VIRGINIA.
LESS INSTABILITY INDICATED THIS AFTERNOON OVER THE MOUNTAIN COUNTIES
COMPARED TO SATURDAY...BUT WITH THE WEAK FLOW AND SOME WEAK E TO W
COMPONENT IN THE LOW LEVELS ON THE EASTERN SLOPES...WILL LEAVE MORE
CLOUDS AND THE 20/30 POPS FOR AFTERNOON AND EARLY EVENING CONVECTION.
STRONGER BUT WEAKENING 500 MB VORT MAXIMUMS STREAK SE FROM NRN IL
AND INDIANA TODAY. THIS SHOULD INCREASE HIGH CLOUDS IN SE OHIO THIS
AFTERNOON...AND MAY HOLD TEMP DOWN A DEGREE OR 2. WILL BE SLOWER
INCREASING POPS IN NE KY AND HTS VCNTY BUT WILL ACTUALLY BE A BIT
FASTER INCREASING POPS FURTHER TO THE NORTH THIS EVENING...IN SE
OHIO...THEN TOWARD THE MID OHIO VALLEY INCLUDING PKB.
00Z MODEL SOLUTIONS DROP WEAKENING 500 MB VORT MAXIMUMS SE THRU CWA
OVERNIGHT SUNDAY NIGHT. QUESTION IS HOW FAST TO INCREASE POPS
FURTHER E...IN RESPONSE TO THESE FEATURES. 00Z GFS SEEMS A BIT
GENEROUS ON LIGHT PCPN FURTHER EAST AND SOUTH OVERNIGHT. WILL HAVE
20 POPS REACHING EKN TO CRW LINE TOWARD DAWN...CHANCE POPS FURTHER
WEST.
WITH INCREASING LAYERED CLOUDS OVERNIGHT...KEPT TEMPS A BIT HIGHER IN
THE MID OHIO VALLEY. STILL THINK THE SRN WV INTO SW VA COAL FIELD
COUNTIES COULD SEE VALLEY FOG OVERNIGHT.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
MODELS IN DECENT AGREEMENT ON MOVEMENT OF SURFACE LOW ACROSS LAKES
ERIE AND ONTARIO THROUGH TUESDAY. THE ECMWF IS THE FASTEST...AND NAM
THE SLOWEST MOVING THE LOW NORTHEAST...WITH THE GFS IN THE MIDDLE.
WARM FRONT WILL LIFT ACROSS CWA MONDAY...AND HAVE LIKELY POPS.
MODELS HAVE TRENDED FARTHER NORTH WITH THE SURFACE LOW...AND NOW
SHOW THE BEST SHEAR REMAINING NORTH OF CWA FOR THE DAY MONDAY. WITH
CONVECTION STARTING EARLY...SOME QUESTION AS TO HOW ORGANIZED THINGS
CAN GET WITH LACK OF STRONG DIURNAL HEATING. PWAT VALUES OF 1.5 TO 2
INCHES WILL LEAD TO DOWNPOURS...BUT THE GROUND HAS DRIED OUT SO DO
NOT ENVISION WIDESPREAD WATER CONCERNS.
MODEL TIMING DIFFERENCES DO HAVE SOME IMPACT ON TIMING THE COLD
FRONT PASSAGE...FOR NOW TRENDED TOWARD THE SLOWER SIDE OF THE
ENVELOPE WITH THE FRONT CROSSING SE OHIO LATE MONDAY NIGHT AND
EXITING THE WV MOUNTAINS EARLY TUESDAY AFTERNOON.
MID AND UPPER LEVEL TROUGH FOLLOW THE COLD FRONT...SO LINGERED
SHOWERS AND CLOUDS INTO TUESDAY EVENING ACROSS THE WEST...AND INTO
TUESDAY NIGHT IN THE WV MOUNTAINOUS COUNTIES. MODELS SHOW UPPER
TROUGH CLOSING OFF ON WEDNESDAY OVER SOUTHERN QUEBEC. WITH NW FLOW
AND WRAPAROUND MOISTURE INCLUDED ISOLATED SHOWERS IN THE NE CWA
WEDNESDAY. MAY EVENTUALLY NEED TO EXPAND THESE WESTWARD...JUST
DEPENDS ON HOW QUICKLY LOW LEVELS DRY OUT.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
A FRESH AIRMASS WILL SETTLE IN FOR THE EXTENDED WITH MILD
COMFORTABLE DAYS AND COOL NIGHTS. SOME MODERATION OVER THE
WEEKEND.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
TIL 00Z...SCT-BKN 2500-4000 FEET AGL ABV 1500 FEET...ELSEWHERE
SCT-BKN 4000-5000 FEET AGL. JUST A FEW MOUNTAIN SHOWERS OR
THUNDERSTORMS 18Z THROUGH 00Z. WILL LEAVE CONFIDENCE AT
MEDIUM...WEAKENING 500 MB VORT MAXIMUMS OVERNIGHT SUNDAY NIGHT. DO
HAVE CHANCE OF A SHOWER OR THUNDERSTORM INTO SE OHIO AFTER
21Z....BUT DIFFICULT TO FIGURE IF SHOWERS WILL CONTINUE TO SURVIVE
AND MOVE DEEPER INTO WV OVERNIGHT.
WILL MENTION SOME SHOWERS PKB AFTER 04Z AND CKB AFTER 08Z MONDAY.
LAYERED CL0UDS AT 5 TO 10 THSD FT INCREASING IN OHIO VALLEY
COUNTIES FOR 00Z TO 06Z MONDAY...THEN AREA WIDE 06Z TO 12Z MONDAY.
VSBY NEAR 5 MILES IN ANY SHOWER SOUTHEAST OHIO AND INTO WV
OVERNIGHT.
DO HAVE PATCHY VALLEY FOG FORMING MAINLY E AND S OF CRW 06Z TO 12Z
MONDAY...INCLUDING THE SOUTHERN WV COAL FIELD VALLEYS. IF CLOUDS ARE
SLOW...THEN FOG AT EKN TOO.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z MONDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: COVERAGE OF SHOWERS 00Z TO 12Z MONDAY MAY BE
MORE THAN FORECAST.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 12 13 14 15 16 17 18 19 20 21 22 23
EDT 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19
CRW CONSISTENCY L L H H H H H H H H H H
HTS CONSISTENCY L H H H H H H H H H H H
BKW CONSISTENCY H H H H H H M M H H H H
EKN CONSISTENCY L L H H H H H H H H H H
PKB CONSISTENCY M H H H H H H H H H H H
CKB CONSISTENCY L L H H H H H H H H H H
AFTER 12Z MONDAY...
IFR POSSIBLE IN SHOWERS AND THUNDERSTORMS MONDAY AND MONDAY
NIGHT...THEN IN LINGERING LOW CEILINGS AND SHOWERS TUESDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/MZ
NEAR TERM...KTB/JMV
SHORT TERM...MZ
LONG TERM...30
AVIATION...KTB/JMV
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
625 AM EDT SUN AUG 9 2015
.SYNOPSIS...
WEAK FLOW CONTINUES TODAY. LOW PRESSURE SYSTEM PASSES
NORTH MONDAY INTO MONDAY NIGHT. MID/UPPER LEVEL TROF AXIS CROSSES
TUESDAY. DRIER AIR WITH COOLER NIGHTS WEDNESDAY AND THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
ANOTHER EARLY MORNING WITH AREAS OF CLOUDS VERSUS VALLEY FOG IN THE
WEAK DOG DAY WIND FLOW. A FEW SHOWERS REDEVELOPED OVER THE CENTRAL
WV MOUNTAINS BETWEEN 06Z AND 08Z PROBABLY AIDED BY A WEAK MID LEVEL
VORT MAX INDICATED ON RAP SOLUTION. BY 10Z FIGURING ANY SURVIVING
SHOWER WOULD BE IN VIRGINIA.
LESS INSTABILITY INDICATED THIS AFTERNOON OVER THE MOUNTAIN COUNTIES
COMPARED TO SATURDAY...BUT WITH THE WEAK FLOW AND SOME WEAK E TO W
COMPONENT IN THE LOW LEVELS ON THE EASTERN SLOPES...WILL LEAVE MORE
CLOUDS AND THE 20/30 POPS FOR AFTERNOON AND EARLY EVENING CONVECTION.
STRONGER BUT WEAKENING 500 MB VORT MAXIMUMS STREAK SE FROM NRN IL
AND INDIANA TODAY. THIS SHOULD INCREASE HIGH CLOUDS IN SE OHIO THIS
AFTERNOON...AND MAY HOLD TEMP DOWN A DEGREE OR 2. WILL BE SLOWER
INCREASING POPS IN NE KY AND HTS VCNTY BUT WILL ACTUALLY BE A BIT
FASTER INCREASING POPS FURTHER TO THE NORTH THIS EVENING...IN SE
OHIO...THEN TOWARD THE MID OHIO VALLEY INCLUDING PKB.
00Z MODEL SOLUTIONS DROP WEAKENING 500 MB VORT MAXIMUMS SE THRU CWA
OVERNIGHT SUNDAY NIGHT. QUESTION IS HOW FAST TO INCREASE POPS
FURTHER E...IN RESPONSE TO THESE FEATURES. 00Z GFS SEEMS A BIT
GENEROUS ON LIGHT PCPN FURTHER EAST AND SOUTH OVERNIGHT. WILL HAVE
20 POPS REACHING EKN TO CRW LINE TOWARD DAWN...CHANCE POPS FURTHER
WEST.
WITH INCREASING LAYERED CLOUDS OVERNIGHT...KEPT TEMPS A BIT HIGHER IN
THE MID OHIO VALLEY. STILL THINK THE SRN WV INTO SW VA COAL FIELD
COUNTIES COULD SEE VALLEY FOG OVERNIGHT.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
MODELS IN DECENT AGREEMENT ON MOVEMENT OF SURFACE LOW ACROSS LAKES
ERIE AND ONTARIO THROUGH TUESDAY. THE ECMWF IS THE FASTEST...AND NAM
THE SLOWEST MOVING THE LOW NORTHEAST...WITH THE GFS IN THE MIDDLE.
WARM FRONT WILL LIFT ACROSS CWA MONDAY...AND HAVE LIKELY POPS.
MODELS HAVE TRENDED FARTHER NORTH WITH THE SURFACE LOW...AND NOW
SHOW THE BEST SHEAR REMAINING NORTH OF CWA FOR THE DAY MONDAY. WITH
CONVECTION STARTING EARLY...SOME QUESTION AS TO HOW ORGANIZED THINGS
CAN GET WITH LACK OF STRONG DIURNAL HEATING. PWAT VALUES OF 1.5 TO 2
INCHES WILL LEAD TO DOWNPOURS...BUT THE GROUND HAS DRIED OUT SO DO
NOT ENVISION WIDESPREAD WATER CONCERNS.
MODEL TIMING DIFFERENCES DO HAVE SOME IMPACT ON TIMING THE COLD
FRONT PASSAGE...FOR NOW TRENDED TOWARD THE SLOWER SIDE OF THE
ENVELOPE WITH THE FRONT CROSSING SE OHIO LATE MONDAY NIGHT AND
EXITING THE WV MOUNTAINS EARLY TUESDAY AFTERNOON.
MID AND UPPER LEVEL TROUGH FOLLOW THE COLD FRONT...SO LINGERED
SHOWERS AND CLOUDS INTO TUESDAY EVENING ACROSS THE WEST...AND INTO
TUESDAY NIGHT IN THE WV MOUNTAINOUS COUNTIES. MODELS SHOW UPPER
TROUGH CLOSING OFF ON WEDNESDAY OVER SOUTHERN QUEBEC. WITH NW FLOW
AND WRAPAROUND MOISTURE INCLUDED ISOLATED SHOWERS IN THE NE CWA
WEDNESDAY. MAY EVENTUALLY NEED TO EXPAND THESE WESTWARD...JUST
DEPENDS ON HOW QUICKLY LOW LEVELS DRY OUT.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
A FRESH AIRMASS WILL SETTLE IN FOR THE EXTENDED WITH MILD
COMFORTABLE DAYS AND COOL NIGHTS. SOME MODERATION OVER THE
WEEKEND.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
LINGERING VALLEY FOG SHOULD DISSIPATE AROUND 13Z.
WILL LEAVE CONFIDENCE AT MEDIUM...WEAKENING 500 MB VORT MAXIMUMS
OVERNIGHT SUNDAY NIGHT. DO HAVE CHANCE OF A SHOWER OR THUNDERSTORM
INTO SE OHIO AFTER 21Z....BUT DIFFICULT TO FIGURE IF SHOWERS WILL
CONTINUE TO SURVIVE AND MOVE DEEPER INTO WV OVERNIGHT.
WILL MENTION SOME SHOWERS PKB AFTER 04Z AND CKB AFTER 08Z MONDAY.
LIKE SATURDAY...MORE DAYTIME CU FIGURED OVER THE MOUNTAIN COUNTIES WITH
CEILINGS 2 TO 3 THSD FT...WHILE MOSTLY SCT CU OVER LOWLANDS AT 3 TO
5 THSD FT AGL. THICKENING CIRRUS CLOUDS ABOVE...ADVANCING ESE AFTER
17Z. A FEW MOUNTAIN SHOWERS OR THUNDERSTORMS 17Z SUNDAY THROUGH 02Z
MONDAY.
LAYERED CL0UDS AT 5 TO 10 THSD FT INCREASING IN OHIO VALLEY COUNTIES
FOR 00Z TO 06Z MONDAY...THEN AREA WIDE 06Z TO 12Z MONDAY. VSBY NEAR
5 MILES IN ANY SHOWER SOUTHEAST OHIO AND INTO WV OVERNIGHT.
DO HAVE PATCHY VALLEY FOG FORMING MAINLY E AND S OF CRW 06Z TO 12Z
MONDAY...INCLUDING THE SOUTHERN WV COAL FIELD VALLEYS. IF CLOUDS ARE
SLOW...THEN FOG AT EKN TOO.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z MONDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: COVERAGE OF SHOWERS 00Z TO 12Z MONDAY. MAY BE
MORE THAN FORECAST.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE SUN 08/09/15
UTC 1HRLY 09 10 11 12 13 14 15 16 17 18 19 20
EDT 1HRLY 05 06 07 08 09 10 11 12 13 14 15 16
CRW CONSISTENCY L L L L L H H H H H H H
HTS CONSISTENCY L L L L H H H H H H H H
BKW CONSISTENCY H H H H H H H H H M M H
EKN CONSISTENCY L L L L L H H H H H H H
PKB CONSISTENCY M M M M H H H H H H H H
CKB CONSISTENCY L L L L L H H H H H H H
AFTER 12Z MONDAY...
IFR POSSIBLE IN SHOWERS AND THUNDERSTORMS MONDAY AND MONDAY
NIGHT...THEN IN LINGERING LOW CEILINGS AND SHOWERS TUESDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/MZ
NEAR TERM...KTB
SHORT TERM...MZ
LONG TERM...30
AVIATION...KTB
AREA FORECAST DISCUSSION
NWS TUCSON AZ
226 PM MST SUN AUG 9 2015
.SYNOPSIS...ISOLATED TO SCATTERED THUNDERSTORMS MAINLY FROM TUCSON
EAST AND SOUTH THROUGH MIDWEEK FOLLOWED BY MARKEDLY REDUCED COVERAGE
OF THUNDERSTORMS BY LATE NEXT WEEK AND INTO THE EARLY PART OF NEXT
WEEKEND. ABOVE NORMAL DAYTIME TEMPERATURES WILL PREVAIL DURING THE
WEEK.
&&
.DISCUSSION...WATER VAPOR IMAGERY AND 09/12Z UPPER-AIR PLOTS SHOW A
RIDGE CENTERED OVER EAST TEXAS WITH A LOW PRESSURE SYSTEM OVER THE
PACIFIC NORTHWEST...AND A SHORTWAVE TROUGH OFF THE SOUTHERN
CALIFORNIA AND NORTHERN BAJA COASTS. A LARGE SWATH OF DRY MID-UPPER
LEVEL AIR COVERS MUCH OF THE EASTERN PACIFIC...SRN CALIFORNIA...
NORTHERN BAJA AND INTO WESTERN ARIZONA.
VISIBLE AND IR SATELLITE IMAGERY INDICATES THAT CUMULUS HAVE BEEN
DEVELOPING MAINLY OVER THE MOUNTAINS WITH THUNDERSTORMS NOW OVER
MOST OF THE MOUNTAIN TOPS. VALLEYS STILL MOSTLY SUNNY TO PARTLY
CLOUDY WITH SOME ACTIVITY PUSHING OFF INTO VALLEYS.
THIS MORNINGS 12Z KTWC SOUNDING REVEALED A DRIER AIRMASS COMPARED TO
24 HOURS AGO...WITH A PW OF 1.47 INCHES. YESTERDAYS 12Z KTWC PW WAS
1.72 INCHES. VARIOUS SOURCES OF PW THIS MORNING POINT TO AROUND 1.4-
1.5 INCHES. AT ANY RATE...ALL OF THIS MORNINGS PARAMETERS ON THE
SOUNDING INDICATE A `RELATIVELY` DRIER AIRMASS...AS WELL AS A TAD
LESS UNSTABLE. STILL AMPLE MOISTURE AND INSTABILITY TO ACCOUNT FOR
ISOLATED TO SCATTERED THUNDERSTORMS THIS AFTERNOON FOR AREAS MAINLY
FROM TUCSON EAST AND SOUTH.
A WEAK DISTURBANCE CAN BE SEEN IN WV IMAGERY OVER SOUTHWEST
CHIHUAHUA MEXICO AND IS COINCIDENT WITH A COMPLEX OVER SRN SONORA.
THIS FEATURE SHOULD HEAD TO THE NORTHWEST THROUGH SONORA AND
EVENTUALLY TOWARD OR INTO SOUTHERN ARIZONA BY LATE TONIGHT. U OF A
WRF/NAM & RR SHOW ACTIVITY INCREASING OVER PARTS OF SANTA CRUZ AND
COCHISE COUNTIES LATE THIS EVENING...THEN THE COMPLEX EVOLVES TO AN
MCV OVER PORTIONS OF COCHISE COUNTY AS IT MOVES NORTH OVERNIGHT AND
EARLY MONDAY. IN ADDITION...MODELS SHOW PW`S INCREASE AS MOIST AIR
FROM THE SOUTH SPREADS NORTH OVERNIGHT AND INTO THE DAY ON MONDAY
WITH VALUES OF AROUND 1.5-1.7 INCHES ACROSS MOST OF THE
AREA...ALTHOUGH LESSER VALUES TOWARD NEW MEXICO. SO ALL THAT
SAID...I TRIED TO REFLECT CHANCE CATEGORY POPS FROM NOW THROUGH
AROUND SUNSET THIS EVENING FOR MOSTLY AREAS FROM TUCSON SOUTH AND
EAST...AND LESSER CHANCES FARTHER WEST. IN ADDITION...WITH THE
DISTURBANCE TO OUR SOUTH POTENTIALLY COMING UP AND TRIGGERING LATE
EVENING CONVECTION AS THE WRF/NAM IS SUGGESTING...MAINLY OVER SANTA
CRUZ AND COCHISE COUNTIES...I KEPT HIGHER POPS IN THAT AREA THROUGH
AROUND 09Z (2 AM MST). THEREAFTER...RAIN CHANCES SHOULD DECREASE
THROUGH MID MORNING MONDAY...BEFORE PICKING BACK UP AGAIN LATE
MONDAY MORNING INTO THE AFTERNOON. MONDAY SHOULD BE AS...OR EVEN
MORE...ACTIVE AS TODAY AS HIGHER MOISTURE...INCREASING INSTABILITY
AND ENHANCEMENT FROM THE DISTURBANCE AFFECTS SOUTHERN ARIZONA.
FOR LATE TUESDAY INTO WEDNESDAY MODELS SUGGEST THAT DRIER AIR WILL
SPREAD IN FROM THE EAST IN RESPONSE TO THE HIGH RETROGRADING TO A
POSITION NEAR EASTERN NEW MEXICO/TEXAS PANHANDLE MIDDAY WEDNESDAY.
THIS WILL RESULT IN THE BEST THREAT FOR THUNDERSTORMS WEDNESDAY
OCCURRING FROM AROUND THE NOGALES AREA TO THE WEST ACROSS THE TOHONO
O`ODHAM NATION.
BY LATE THURSDAY THE HIGH SHOULD BE IN THE GENERAL VICINITY OF
WESTERN/NORTHERN NEW MEXICO WITH EVEN LESSER RAIN CHANCES...
GENERALLY JUST ISOLATED IN NATURE FOR DESERTS/VALLEYS AND LOW END
SCATTERED FOR MOUNTAINS. A SIMILAR PICTURE FOR FRIDAY AND SATURDAY
AS THE HIGH SHOULD BE IN VIRTUALLY THE SAME LOCATION.
BY SUNDAY THE HIGH SHOULD BE OVER THE AZ/NM BORDER PER THE GFS
SOLUTION...OR OVER WESTERN AZ...BASED ON THE ECMWF. SOME RETURN IN
MOISTURE IS EXPECTED AT THAT TIME WITH A SLIGHT UPTICK IN RAIN
CHANCES.
FOR TUCSON...HIGH TEMPERATURES WILL GENERALLY BE NEAR NORMAL
MONDAY...THEN RANGING FROM 5 TO 8 DEGS ABOVE NORMAL DURING THE REST
OF THE FORECAST PERIOD...ALTHOUGH THE WARMEST DAYS WILL OCCUR
THURSDAY AND FRIDAY. LOW TEMPS WILL RANGE FROM AROUND 3 TO 5 DEGS
ABOVE NORMAL EACH MORNING.
&&
.AVIATION...VALID THRU 11/00Z.
ISO/SCT -TSRA/-SHRA POSSIBLE NEAR MOST TERMINALS THIS AFTERNOON
AND EVENING...WITH A FOCUS NEAR KOLS AND KDUG. ACTIVITY WILL
CONTINUE INTO TONIGHT...EVENTUALLY TRANSITIONING FROM MOSTLY
-TSRA TO MOSTLY -SHRA AFTER 10/08Z...-SHRA LINGERING A BIT LONGER
NEAR KDUG. BRIEF MVFR CONDITIONS AND WIND GUSTS 30 TO 40 KTS WILL
BE POSSIBLE NEAR STRONGER STORMS. OTHERWISE...OUTSIDE OF
THUNDERSTORM INFLUENCE SKIES WILL GENERALLY BE SCT TO BKN 7 TO 12
KFT...WITH DIURNAL WINDS GENERALLY UNDER 12 KTS. SCT TSRA/-SHRA WILL
AGAIN BE POSSIBLE AFTER 19/20Z NEAR MOST TERMINALS. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL
CONTINUE THIS AFTERNOON AND EVENING...WITH A FOCUS SOUTH AND EAST OF
TUCSON. SCATTERED ACTIVITY WILL THEN SPREAD ACROSS MUCH OF SOUTHEAST
ARIZONA MONDAY AND TUESDAY BEFORE A WARMING AND DRYING TREND LIMITS
ACTIVITY FOR THE LATTER PART OF THE WEEK. HOWEVER...THERE WILL STILL
BE ENOUGH MOISTURE FOR ISOLATED TO SCATTERED THUNDERSTORMS OVER THE
WHITE MOUNTAINS AND IN THE HIGHER ELEVATIONS SOUTH OF TUCSON.
OUTSIDE OF THUNDERSTORM WIND GUSTS...20-FT WINDS WILL GENERALLY BE
LIGHT AND DIURNAL AT LESS THAN 15 MPH. HOWEVER...THERE WILL STILL BE
SOME OCCASIONAL AFTERNOON AND EARLY EVENING GUSTINESS.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...MOLLERE
AVIATION/FIRE WEATHER...HUMPHREYS
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
908 AM MST SUN AUG 9 2015
.SYNOPSIS...
STORM CHANCES WILL WANE WITH WARMING TEMPERATURES ACROSS THE ENTIRE
AREA TODAY AS DRIER AIR MOVES INTO THE AREA THROUGH THE BEGINNING OF
THE WEEK. A RETURN TO A MORE TYPICAL MONSOON FLOW WILL OCCUR BY THE
MIDDLE OF THE WEEK...ALTHOUGH DRIER AIR SHOULD ONCE AGAIN OVERSPREAD
THE AREA THURSDAY INTO NEXT WEEKEND.
&&
.DISCUSSION...
RELATIVELY SHARP MOISTURE GRADIENT PERSISTS ACROSS THE AREA WITH
SURFACE DEWPOINTS IN THE LOWER 40S ALONG THE CO RIVER VALLEY AND MID
TO UPPER 60S IN THE PHOENIX AREA. MORNING PSR SOUNDING AND TEMPE GPS-
IPW MEASURED A PWAT OF 1.5 INCHES...WHICH IS NEAR THE CLIMATOLOGICAL
MEAN.
LATEST CAMS INCLUDING THE HRRR CONTINUE TO SUGGEST THAT CONVECTION
WILL BE MOST CONCENTRATED ACROSS EASTERN AZ THIS AFTERNOON.
MEANWHILE...WARMING TREND WILL CONTINUE WITH SLIGHTLY ABOVE NORMAL
TEMPERATURES EXPECTED. ONLY MINOR ADJUSTMENTS TO THE SHORT-TERM
TEMPERATURES ARE ANTICIPATED THIS MORNING.
&&
.PREVIOUS DISCUSSION...
EARLY MORNING WATER VAPOR IMAGERY AND UPPER AIR DATA CONTINUE TO
DEPICT BROAD SOUTHWESTERLY FLOW ACROSS THE REGION...WITH A SHARP
MOISTURE GRADIENT STRETCHING FROM THE FOUR CORNERS THROUGH PHOENIX
AND INTO THE GULF OF CALIFORNIA. PWATS PER BLENDED TPW IMAGERY ARE
GENERALLY AROUND 0.5-0.6 INCHES ACROSS SOUTHEAST CALIFORNIA AND
CLOSER TO 1.4-1.5 ALONG THE ARIZONA/NEW MEXICO BORDER. NOT
SURPRISINGLY MOST OF THE STORM ACTIVITY ON SATURDAY WAS CONFINED TO
THE MOISTURE-RICH AREAS SOUTH/EAST OF PHOENIX. STORMS HAVE LONG SINCE
DIED OUT WITH MOSTLY CLEAR SKIES PREVALENT ACROSS THE REGION AS OF
08Z.
THE WEST-TO-EAST DRYING TREND WILL CONTINUE TODAY WITH DRY AIR
EVENTUALLY FORECAST TO SPREAD ALL THE WAY TO GILA COUNTY THIS
AFTERNOON. HARD TO IMAGINE THAT THERE WON`T BE AT LEAST SOME STORM
ACTIVITY EAST OF PHOENIX TODAY...SPC SSEO AND NCAR HI-RES ENSEMBLE
SUGGEST A FEW SHOWERS. MAINTAINING 10-20 POPS EAST OF PHOENIX THIS
AFTERNOON AND EVENING FOR THAT REASON.
LOOKING AHEAD TO MONDAY...THE MID LEVEL 700-300MB STEERING FLOW WILL
BEGIN TO TAKE ON A MORE TYPICAL MONSOONAL PATTERN WITH WEAK MOISTURE
ADVECTION EXPECTED TO COMMENCE MONDAY AFTERNOON. GLOBAL MODELS AND
CONVECTIVE ALLOWING MODELS SUGGEST THE MAJORITY OF THE STORM ACTIVITY
WILL BE CONFINED TO THE MOUNTAINS EAST OF PHOENIX MONDAY AFTERNOON
AND THIS SEEMS REASONABLE. TUESDAY COULD BE A BIT MORE ACTIVE AS
DEEPER MOISTURE IS FORECAST TO MOVE INTO THE AREA FROM THE SOUTHEAST.
THIS INFLUX OF MOISTURE WILL ALSO ARRIVE COINCIDENT WITH THE PASSAGE
OF AN UPPER LEVEL PV ANOMALY AS WELL AS AN INVERTED MID LEVEL TROUGH.
BOTH GFS/EC INDICATE THESE FEATURES AND THEY`RE ALSO BEING REFLECTED
IN SOME OF THE LONGER-RANGE HI-RES GUIDANCE. MADE SOME MINOR UPWARD
ADJUSTMENTS TO POPS FOR TUESDAY/TUESDAY NIGHT ACCORDINGLY. OF
COURSE...JUST HOW ACTIVE TUESDAY IS WILL DICTATE HOW ACTIVE WEDNESDAY
WILL BE AS CONDITIONS WILL REMAIN FAIRLY UNCHANGED. STICKING WITH THE
IDEA OF A DOWN DAY CONVECTIVELY ON WEDNESDAY ALTHOUGH NOT NEARLY
CONFIDENT ENOUGH TO CUT BACK POPS. STICKING WITH A BROAD-BRUSHED
10-20 POP FORECAST FOR ALL LOCATIONS ON WEDNESDAY AT THIS POINT AND
THIS SEEMS SUPPORTED BY THE ENSEMBLES.
DRY ADVECTION STILL LOOKS LIKELY LATER IN THE WEEK AS THE BOUNDARY
LAYER SEES MIXING RATIOS FALL TO 4-5 G/KG THURSDAY AND FRIDAY
COURTESY OF EASTERLY FLOW VS. SOUTHEASTERLY FLOW. NOT ONLY WILL THIS
SERVE TO REDUCE RAINFALL CHANCES...BUT IT WILL ALSO LEAD TO
INCREASING TEMPERATURES LATE IN THE WEEK. LATEST BLENDED GUIDANCE IS
SUGGESTING DESERT HIGHS IN THE 110-113 RANGE LATE IN THE WEEK AND
OUR FORECAST HIGHS WERE RAISED A FEW DEGREES. IF THIS TREND CONTINUES
AND/OR EVEN DRIER AIR IS ADVECTED INTO THE AREA...MAY NEED TO LOOK AT
EXCESSIVE HEAT WARNINGS FOR PORTIONS OF THE FORECAST AREA. SOME
MOISTURE WILL RETURN BY NEXT WEEKEND...PUTTING THE BRAKES ON THE
WARMING TREND.
&&
.AVIATION......SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND
KSDL...
DRY SOUTHWESTERLY FLOW ALOFT WILL KEEP THUNDERSTORM ACTIVITY WELL
OFF TO THE EAST AND CLOUD COVERAGE DOWN INTO THE FEW-SCT RANGE
THROUGH THE TAF PERIOD WITH CLOUD BASES REMAINING MAINLY AOA 10K
FEET. WINDS TO REMAIN MAINLY ON THE LIGHT SIDE THROUGH THE TAF
PERIOD...MAINLY AOB 8 KTS...MAINLY FOLLOWING TYPICAL DIURNAL TRENDS.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
DRY SOUTHWESTERLY FLOW ALOFT TO KEEP SKIES MAINLY CLEAR THROUGH THE
TAF PERIOD. WINDS TO REMAIN MAINLY FROM A SOUTHERLY DIRECTION AT
KBLH AND FOLLOW TYPICAL DIURNAL TRENDS AT KIPL.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
A SUBTLE RETURN OF MONSOON MOISTURE COUPLED WITH SOME PASSING UPPER
LEVEL DISTURBANCES FROM THE SOUTHEAST WILL RAISE STORM CHANCES AND
HUMIDITIES FOR TUESDAY. STORM CHANCES WILL EXPAND OUT OF THE EASTERN
AZ HIGHER TERRAIN THROUGH THE LOWER DESERT LOCALES AND TOWARDS THE
CO RIVER VALLEY. CONDITIONS DRY OUT AGAIN BY THE MIDDLE PART OF THE
WEEK AND DAYTIME TEMPERATURES RESPOND IN KIND...WITH THE POTENTIAL
TO GO ABOVE SEASONALLY NORMAL READINGS. WINDS WILL BE LIGHT THROUGH
MUCH OF THE PERIOD FOLLOWING TYPICAL DIURNAL DIRECTIONS EXCEPT FOR
AFTERNOON UPSLOPE BREEZES GUSTING AT TIMES UP TO 20 MPH.
&&
.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT CONDITIONS ACCORDING TO STANDARD
OPERATING PROCEDURES.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...HIRSCH
PREVIOUS DISCUSSION...LEINS
AVIATION...PERCHA
FIRE WEATHER...NOLTE
AREA FORECAST DISCUSSION...CORRECTED
NWS GRAND JUNCTION CO
303 PM MDT SUN AUG 9 2015
CORRECTED WORDING IN LONG TERM
.SHORT TERM...(TONIGHT THROUGH MONDAY NIGHT)
ISSUED AT 302 PM MDT SUN AUG 9 2015
SIGNIFICANTLY DRIER AIR WILL REMAIN OVER THE AREA OVERNIGHT. THE
12Z KGJT SOUNDING HAD PRECIPITABLE WATER OF 0.63 IN. DEWPOINTS
WILL CONTINUE TO DROP INTO THE 40S AND EVEN UPPER 30S AT SOME
LOCATIONS. CAPE VALUES ARE PROJECTED IN THE RAP13 AND HRRR TO
REMAIN LOW AS WELL...SO CONVECTION EARLY THIS EVENING WILL BE
WEAK AND ONLY OVER AND DOWNWIND OF RIDGES. ONLY LIGHT
PRECIPITATION IS EXPECTED WITH THESE STORMS ALONG WITH GUSTY
WINDS. THUNDERSTORMS SHOULD DISSIPATE WELL BEFORE MIDNIGHT WITH
NEARLY CLEAR SKIES EXPECTED AGAIN OVERNIGHT.
MOISTURE BEGINS TO INCREASE FROM THE SOUTH AGAIN ON MONDAY...SO EXPECTING
SCATTERED ACTIVITY IN THE SAN JUANS MONDAY EVENING AS THE 12Z NAM
AND GFS INDICATE A H5 VORTICITY MAX REACHING THE FOUR CORNERS
MONDAY EVENING. THE EURO IS A BIT SLOWER WITH THIS ENERGY...BUT IN
ANY CASE IT DOES LOOK LIKE SHOWERS AND ISO TSTORMS WILL CONTINUE
THROUGH THE OVERNIGHT HOURS ON MONDAY NIGHT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 302 PM MDT SUN AUG 9 2015
TUESDAY MORNING WILL BE A MUGGY ONE...WITH CLOUD COVER AND RAIN
SHOWERS ACROSS MUCH OF THE REGION BY MIDDAY. MONSOONAL MOISTURE
WILL BE AT ITS HIGHEST THIS WEEK ON TUESDAY AFTERNOON AS
PRECIPITABLE WATER VALUES ACROSS THE FOUR CORNERS REACH UPWARDS OF
1.2 INCHES AND MORE THAN 0.75 INCHES REACHING THE UT/CO/WY BORDER.
THOUGH DEEP MOISTURE WILL BE IN PLACE...NOT FEELING VERY CONFIDENT
ON THE THREAT OF FLASH FLOODING SINCE WE WILL LIKELY BE DEALING
WITH WIDESPREAD CLOUD COVER AGAIN AND LACK OF LIFTING DUE TO
DAYTIME HEATING. LOCALIZED FLASH FLOODING COULD OCCUR IF THERE IS
SOME CLEARING WHICH PRODUCES ENOUGH LIFT FOR MORE VERTICALLY
SUPPORTED THUNDERSTORMS. WEDNESDAY WILL LIKELY BE MORE OF A THREAT
DAY FOR FLASH FLOODING WITH SKY CONDITIONS LESS CLOUDY BUT WITH
DEEP MOISTURE STILL IN PLACE. FORECAST CONVECTIVE INDICES ON THE
NAM ARE MORE FAVORABLE FOR HEAVY RAIN PRODUCING THUNDERSTORMS ON
WEDNESDAY THAN TUESDAY...SO THESE DAYS WILL NEED TO BE WATCHED FOR
POTENTIAL IMPACTS. THE LACK OF JET SUPPORT WILL KEEP STEERING
WINDS LIGHT THROUGH THE END OF THE WEEK SO ANY SHOWERS AND STORMS
WHICH DEVELOP WILL MOVE SLOWLY. SOME DRYING OCCURS LATER IN THE
WORK WEEK DUE TO HIGH PRESSURE AMPLIFYING OVER THE ROCKIES...BUT
PRECIPITABLE WATER VALUES REMAIN NEAR THREE QUARTERS OF AN INCH
SO DIURNALLY INDUCED SHOWERS AND THUNDERSTORMS WILL DEVELOP
EVERYDAY OVER HIGHER TERRAIN.
NEXT SATURDAY...A TROUGH OVER THE PACIFIC NORTHWEST IS PROGGED TO MOVE
INLAND NORTH OF COLORADO. THE INTERACTION OF THIS TROUGH WITH THE
HIGH PRESSURE IN PLACE OVER THE ROCKIES WILL DRIVE A 50 KT JET
INTO NE UTAH AND NW COLORADO AND POTENTIALLY CREATE MORE
CONVECTIVE ACTIVITY UP NORTH NEXT WEEKEND.
BUMPED HIGH TEMPS UP A COUPLE OF DEGREES IN THE LOWER VALLEYS
TOWARD THE END OF THE WEEK CLOSER TO MOS GUIDANCE FOR A MIDDLE
GROUND SOLUTION. FEEL THAT MOS GUIDANCE IS TOO HOT BUT PREVIOUS
FORECAST WAS TOO LOW CONSIDERING THE EXPECTED AMOUNT OF SUNSHINE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 302 PM MDT SUN AUG 9 2015
VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES THE NEXT 24 HOURS.
THROUGH ABOUT 02Z ISOLATED THUNDERSTORMS WILL CONTINUE OVER THE
MOUNTAINS OF NORTHERN AND CENTRAL COLORADO...AND EASTERN UTAH...
WITH SCATTERED STORMS OVER THE SAN JUAN MOUNTAINS. LOCAL MODERATE
RAIN SHOWERS AND WIND GUSTS TO 35 MPH ARE POSSIBLE IN THE VICINITY
OF THESE STORMS. AREAL COVERAGE OF THUNDERSTORMS WILL INCREASE A
BIT MONDAY AFTERNOON OVER SOUTHWEST COLORADO AND CENTRAL COLORADO
NEAR THE CONTINENTAL DIVIDE.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...CC/JAM
LONG TERM...JAM
AVIATION...CC
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
508 PM CDT SUN AUG 9 2015
.SHORT TERM...
219 PM CDT
THROUGH MONDAY...
THINKING THIS AFTERNOON AND EVENING WILL BE RELATIVELY QUIET AND
POSSIBLY QUIETER THAN WHAT IS CURRENTLY FORECAST. STRAY SHOWERS ARE
OUT OVER THE LAKE AND SOUTH OF I-80 NEAR OTTAWA AND OVER NW
INDIANA. THE MCV FROM THIS MORNING/S COMPLEX IS SPINNING OVER
WESTERN MO AND SOUTHERN IL BASED ON SATELLITE DATA WITH NEW
CONVECTION FIRING OVER NORTHERN MO. THE LATEST RAP ANALYSIS
INDICATES THERE IS ABOUT 500 J/KG OF CAPE OVER THE FAR SOUTHERN
CWA WITH LITTLE TO NO CAPE OVER THE REST OF THE CWA.
GUIDANCE IS STRUGGLING WITH WHERE CONVECTION WILL FIRE GOING INTO
THIS AFTN AND HAVE LOW CONFIDENCE IN THE EXACT DETAILS MYSELF.
THINKING THE MAJORITY OF CONVECTION WILL OCCUR TO THE WEST AND SOUTH
OF THE CWA...BUT CANNOT RULE OUT A FEW SHOWERS AND/OR STORMS AS THE
MCV SHIFTS EAST OVER SOUTHERN IL. LOWERED PRECIP CHANCES INTO THE
CHANCE RANGE BELOW 50% AT BEST WITH THE HIGHEST VALUES SOUTH OF I-
80. WHILE STORMS MAY PRODUCE HEAVY DOWNPOURS AND A GUST OF
WIND...SEVERE WEATHER IS NOT EXPECTED. ONCE AGAIN...AREAS NORTH OF
I-88 MAY END UP BEING DRY BUT DID NOT HAVE ENOUGH CONFIDENCE TO GO
DRY AT THIS TIME. LONG STORY SHORT...ISOLATED SHOWERS ARE POSSIBLE
NORTH OF I-80 WITH ISOLATED TO SCATTERED SHOWERS AND A FEW STORMS
SOUTH OF I-80.
AS THE MCV SHIFTS EAST THIS EVENING...THE THREAT OF SHOWERS AND
STORMS WILL ALSO SHIFT TO LOCATIONS ALONG AND EAST OF I-55.
EXPECTING FOG TO DEVELOP OVERNIGHT AS WINDS DIMINISH AND SATURATED
AIR COOLS. SOME AREAS MAY SEE DENSE FOG...VSBY OF 1/4 A MILE OR
LESS...BUT AS OF RIGHT NOW EXPECTING MOSTLY AREAS OF FOG WITH VSBY
GREATER THAN 1/4 OF A MILE.
A SHORTWAVE TROUGH TRAVELS ACROSS WI TOMORROW WITH VORTICITY
STREAMERS PASSING OVER FAR NORTHERN IL. THINKING SCATTERED SHOWERS
AND STORMS WILL FORM ALONG THE VORT STREAMERS WITH BETTER COVERAGE
NORTH OF I-80 ESPECIALLY ALONG THE WI/IL STATE LINE. THINKING
COVERAGE WILL BE HIT OR MISS WITH PLENTY OF RAIN FREE HOURS. DID
NOT MAKE MANY CHANGES TO HIGH TEMPS MONDAY WITH COOLER AIR SINKING
IN FROM THE NORTH AND THICK CLOUD COVER. EXPECTING HIGHS AROUND 80
ALONG THE IL/WI STATE LINE AND ALONG THE LAKE WITH LOW TO MID 80S
SOUTH OF I-80.
JEE
&&
.LONG TERM...
MONDAY NIGHT THROUGH SUNDAY...
251 PM...MAIN FORECAST CONCERN IS THE CHANCE OF THUNDERSTORMS
THURSDAY NIGHT THRU FRIDAY NIGHT.
WEAK LOW PRESSURE IS EXPECTED TO BE EAST OF THE AREA AND MOVING
ACROSS THE SOUTHERN GREAT LAKES REGION MONDAY EVENING. THERE IS A
SLIGHT CHANCE OF AN EVENING SHOWER OR THUNDERSTORM BUT ANY ACTIVITY
SHOULD BE QUICKLY DIMINISHING BY MID/LATE EVENING. HIGH PRESSURE
THEN BUILDS ACROSS THE REGION TUESDAY AND WEDNESDAY. NORTHERLY
WINDS MAY BE A BIT BREEZY NEAR THE LAKE INTO NORTHWEST INDIANA
TUESDAY WITH THE CENTER OF THE HIGH STILL WEST OF THE AREA WITH
CONTINUED LIGHTER NORTHERLY WINDS ON WEDNESDAY...WITH COOLER TEMPS
AT THE LAKESHORE BOTH DAYS.
WEDNESDAY NIGHT/THURSDAY MORNING WILL BE A BIT COOLER WITH LOWS
POSSIBLY IN THE MID/UPPER 50S AWAY FROM THE URBAN AREAS. BUT AS
THE HIGH SHIFTS EAST THURSDAY...WARMER SOUTHWESTERLY FLOW WILL
RETURN WITH WINDS PERHAPS BECOMING BREEZY THURSDAY AFTERNOON.
HIGHS WILL LIKELY REBOUND INTO THE MID 80S THOUGH STILL SOME
DIFFERENCES REGARDING HOW MUCH WARMER TEMPS COULD BECOME.
DIFFERENCES BEGIN TO SHOW UP FRIDAY AND FRIDAY NIGHT WITH THE GFS
BRINGING A FRONTAL BOUNDARY ACROSS THE AREA FRIDAY AFTERNOON/
EVENING WHILE THE ECMWF KEEPS THIS FRONT NORTH OF THE CWA. A
LITTLE TOO EARLY TO DETERMINE SPECIFICS BUT GRADIENT APPEARS
LIGHT ENOUGH THAT A LAKE BREEZE IS POSSIBLE FRIDAY AFTERNOON.
PRECIP CHANCES WILL LIKELY DEPEND ON HOW MUCH OF THE FRONTAL
BOUNDARY REACHES THE AREA. HAVE LOW CHANCE POPS FOR NOW...BUT
CONFIDENCE IS FAIRLY LOW. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* VARIABLE WIND DIRECTIONS WITH SPEEDS LESS THAN 10 KTS TRENDING
SOUTHEAST- EAST THROUGH EARLY EVENING.
* PATCHY LIGHT RAIN NEXT 1-2 HOURS BUT GENERALLY VFR CONDITIONS.
* LOWERING CEILINGS THROUGH TONIGHT...BECOMING WIDESPREAD MVFR
WITH PERIODS OF IFR. VLIFR ALSO POSSIBLE.
* ISOLATED THUNDER CHANCE LATE MONDAY AFTERNOON.
MM/RATZER
//DISCUSSION...UPDATED 18Z...
RADAR AND OBSERVATION TRENDS INDICATE IMPROVED VSBY AND CEILINGS
FOR THE REMAINDER OF THE AFTERNOON AS A WEAKENING THUNDERSTORM
COMPLEX PASSES/DIES NEAR IND. SOME SITES IN WI CONTINUE TO
INDICATE MVFR CIGS WHICH MAY BRIEFLY SNEAK INTO THE TAF SITES.
AS LOW PRESSURE CONTINUES TO PASS SOUTH AND EAST OF THE
AREA...WINDS WILL REMAIN EAST...TURNING MORE NORTHERLY MONDAY.
REMNANT LOW LEVEL MOISTURE AND A TEMPERATURE INVERSION WILL KEEP
FOG LIKELY FOR TONIGHT. MODEL CONSENSUS INDICATES IFR IS LIKELY
WITH VLIFR ALSO POSSIBLE. IMPROVEMENTS WILL START AFTER SUNRISE
MONDAY...BUT VFR CONDITIONS ARE NOT EXPECTED UNTIL LATE MORNING.
THUNDER CHANCES REMAIN QUITE LOW FOR MONDAY...DEPENDING ON THE
DEGREE OF HEATING TOMORROW AND THE DEVELOPMENT OF A FORCING
MECHANISM. STILL NOT OUT OF THE QUESTION THOUGH.
MM
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* MEDIUM-HIGH ON WINDS.
* HIGH ON MVFR OVERNIGHT...MEDIUM ON IFR...LOW ON VLIFR.
* LOW ON THUNDER CHANCES MONDAY.
MM/RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...SLIGHT CHANCE OF THUNDERSTORMS EARLY.
TUESDAY...VFR.
WEDNESDAY...VFR.
THURSDAY...VFR.
FRIDAY...CHANCE OF THUNDERSTORMS.
SATURDAY...VFR.
RODRIGUEZ
&&
.MARINE...
251 PM...LOW PRESSURE OVER NORTHERN ONTARIO WILL MOVE INTO QUEBEC
BY MONDAY EVENING. A TRAILING COLD FRONT WILL MOVE ACROSS THE LAKE
LATE TONIGHT INTO MONDAY MORNING SHIFTING WINDS NORTHERLY. ANOTHER
WEAK LOW WILL MOVE SOUTH OF THE LAKE MONDAY AFTERNOON AS HIGH
PRESSURE BUILDS INTO THE NORTHERN PLAINS. THE GRADIENT WILL
TIGHTEN BETWEEN THESE TWO FEATURES WITH NORTHERLY WINDS INCREASING
TO 15-25 KTS BY TUESDAY MORNING. AS THE HIGH MOVES EAST...THESE
NORTHERLY WINDS WILL SLOWLY DIMINISH TUESDAY NIGHT INTO WEDNESDAY.
WINDS WILL SHIFT TO THE SOUTHWEST WEDNESDAY NIGHT AS THE HIGH
SETTLES SOUTHEAST OF THE LAKE AND DEPENDING ON HOW STRONG THE
GRADIENT BECOMES...SPEEDS MAY INCREASE INTO THE 15-25KT RANGE
THURSDAY INTO THURSDAY NIGHT. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS LINCOLN IL
253 PM CDT SUN AUG 9 2015
.SHORT TERM...(TONIGHT)
ISSUED AT 253 PM CDT SUN AUG 9 2015
BASED ON SURFACE DATA...APPEARS THERE IS A BOUNDARY STRETCHING FROM
NORTHERN MO/SOUTHERN IA INTO NORTHERN PART OF CENTRAL IL.
HOWEVER...THE EFFECTIVE BOUNDARY SHOULD BE MUCH FURTHER SOUTH AS A
RESULT OF THE MCS THAT MOVED ACROSS THE AREA EARLIER THIS MORNING
PUSHING IT SOUTH OF THE CWA. HRRR DOES NOT SHOW ANY PCPN IN THE CWA
TONIGHT...BUT DOES HAVE THE SMALL AREA OF PCPN IN NORTHERN MO MOVING
EAST-SOUTHEAST INTO SOUTHERN IL THIS EVENING. BUT WITH A WEAK
CONVERGENT BOUNDARY IN THE AREA AM INCLINED TO KEEP A CHANCE FOR
POPS IN THE FORECAST FOR TONIGHT. TREND SHOULD BE...AND MODELS DO
SUPPORT THAT THIS WEAK BOUNDARY SHOULD MOVE SOUTH DURING THE
OVERNIGHT PERIOD. SO CHANCE POPS SOUTHEAST OF THE ILLINOIS RIVER
TONIGHT. ENDING OF PCPN CHANCES WILL START ALONG THE RIVER AND THEN
PROGRESS SOUTHEAST THROUGH THE PERIOD. OTHER ISSUE OVERNIGHT WILL BE
FOG DEVELOPMENT. WITH LOTS OF BREAKS IN THE CLOUDS THIS EVENING AND
OVERNIGHT...COMBINED WITH THE ABUNDANCE OF LOW LEVEL MOISTURE FROM
THE RAIN THIS MORNING...AND LIGHT WINDS...BELIEVE FOG WILL DEVELOP
THIS EVENING AND CONTINUE INTO THE OVERNIGHT HOURS. SO HAVE INCLUDED
AREAS OF FOG IN THE FORECAST THE NORTHERN AND CENTRAL PARTS OF THE
AREA. ONLY PLACE WITHOUT ANY FOG WILL BE AREAS SOUTHEAST OF I-70.
OVERNIGHT LOWS AROUND 70S LOOKS REASONABLE WITH COOLEST TEMPS UP
NORTH WHERE MORE BREAKS IN CLOUDS SHOULD BE.
&&
.LONG TERM...(MONDAY THROUGH SUNDAY)
ISSUED AT 253 PM CDT SUN AUG 9 2015
A FRONTAL BOUNDARY CURRENTLY FROM NORTHERN WISCONSIN TO NORTHERN
NEBRASKA WILL PUSH INTO SOUTHEAST ILLINOIS BY MID MORNING
MONDAY...AIDED BY SEVERAL AREAS OF THUNDERSTORM DEVELOPMENT AHEAD OF
THE FRONT THIS EVENING INTO TONIGHT. THE EFFECTIVE FRONT WILL LIKELY
BE LINGERING IN SOUTHEAST PORTIONS OF THE CENTRAL IL FORECAST AREA
THROUGH THE MORNING AND HAVE CONTINUED PRECIPITATION CHANCES IN THAT
AREA THROUGH NOON. MOST OF THE THUNDERSTORM ACTIVITY WILL TEND TO
MOVE EASTWARD THROUGH THE DAY...HOWEVER AN UPPER LEVEL SHORTWAVE
WILL APPROACH FROM THE NORTHWEST BY AFTERNOON...AND LIFT ASSOCIATED
WITH THIS FEATURE WILL CAUSE CHANCES FOR SHOWERS AND THUNDERSTORMS
TO RE-DEVELOP FOR AFTERNOON AND EARLY EVENING...MAINLY FROM THE
ILLINOIS RIVER NORTHWESTWARD. HIGHS EXPECTED TO REACH FROM AROUND 81
IN GALESBURG TO THE MID 80S SPRINGFIELD TO PARIS SOUTHWARD WITH
WINDS BECOMING NORTHWEST UP TO 10 MPH.
AFTER THIS FEATURE PASSES THROUGH...DRY CONDITIONS ARE EXPECTED
THROUGH MUCH OF THE WEEK AS A PRONOUNCED UPPER LEVEL RIDGE BUILDS
OVER THE CENTRAL U.S. AND TROUGHING OVER THE NORTHEASTERN U.S. A
COOL NORTHWEST FLOW PATTERN BETWEEN THE RIDGE AND TROUGH WILL BRING
HIGH TEMPERATURES PRIMARILY IN THE LOW 80S AND LOWS IN THE LOW 60S
THROUGH THURSDAY. A COLD FRONT EMBEDDED IN THIS FLOW PATTERN WILL
DROP INTO THE GREAT LAKES/MIDWEST AREA FRIDAY. MODELS CONTINUE SOME
RUN TO RUN INCONSISTENCIES FOR THIS FEATURE...BUT BULK OF GUIDANCE
CONTINUES TO SUGGEST PRECIPITATION ASSOCIATED WITH THIS FEATURE MAY
STRUGGLE TO REACH AS FAR SOUTHWEST AS CENTRAL ILLINOIS.
THEREFORE...HAVE INCORPORATED SLIGHT CHANCES FOR THUNDERSTORMS
MAINLY I-72 NORTHWARD. DRY CONDITIONS SHOULD THEN RETURN THROUGH THE
WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1232 PM CDT SUN AUG 9 2015
MCS HAS DECAYED AND MOVED EAST OF THE TAF SITES LATE THIS MORNING.
THIS HAS PUSHED THE EFFECTIVE FRONT SOUTH OF THE TAFS AND CURRENT
THINKING...WHICH IS SUPPORTED BY THE CURRENT HRRR MODEL
RUN...SHOWS ALL PCPN SHOULD BE SOUTH OF THE TAF SITES THIS
AFTERNOON AND TONIGHT. ONLY CONCERN IS WITH WINDS BECOMING
LIGHTER AND SKIES BECOMING MOSTLY CLEAR...WITH ALL THE MOISTURE
HAD THIS MORNING...BELIEVE FOG WILL BE AN ISSUE THIS EVENING AND
INTO THE OVERNIGHT HOURS. SO HAVE INCLUDED MVFR CONDITIONS THIS
EVENING AND THEN GOING WITH IFR CONDITIONS DURING THE OVERNIGHT.
WINDS WILL BE SOUTHERLY REMAINDER OF THE AFTERNOON AND THEN BECOME
LIGHT AND VARIABLE THIS EVENING AND OVERNIGHT.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...AUTEN
LONG TERM...ONTON
AVIATION...AUTEN
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
251 PM CDT SUN AUG 9 2015
.SHORT TERM...
219 PM CDT
THROUGH MONDAY...
THINKING THIS AFTERNOON AND EVENING WILL BE RELATIVELY QUIET AND
POSSIBLY QUIETER THAN WHAT IS CURRENTLY FORECAST. STRAY SHOWERS ARE
OUT OVER THE LAKE AND SOUTH OF I-80 NEAR OTTAWA AND OVER NW
INDIANA. THE MCV FROM THIS MORNING/S COMPLEX IS SPINNING OVER
WESTERN MO AND SOUTHERN IL BASED ON SATELLITE DATA WITH NEW
CONVECTION FIRING OVER NORTHERN MO. THE LATEST RAP ANALYSIS
INDICATES THERE IS ABOUT 500 J/KG OF CAPE OVER THE FAR SOUTHERN
CWA WITH LITTLE TO NO CAPE OVER THE REST OF THE CWA.
GUIDANCE IS STRUGGLING WITH WHERE CONVECTION WILL FIRE GOING INTO
THIS AFTN AND HAVE LOW CONFIDENCE IN THE EXACT DETAILS MYSELF.
THINKING THE MAJORITY OF CONVECTION WILL OCCUR TO THE WEST AND SOUTH
OF THE CWA...BUT CANNOT RULE OUT A FEW SHOWERS AND/OR STORMS AS THE
MCV SHIFTS EAST OVER SOUTHERN IL. LOWERED PRECIP CHANCES INTO THE
CHANCE RANGE BELOW 50% AT BEST WITH THE HIGHEST VALUES SOUTH OF I-
80. WHILE STORMS MAY PRODUCE HEAVY DOWNPOURS AND A GUST OF
WIND...SEVERE WEATHER IS NOT EXPECTED. ONCE AGAIN...AREAS NORTH OF
I-88 MAY END UP BEING DRY BUT DID NOT HAVE ENOUGH CONFIDENCE TO GO
DRY AT THIS TIME. LONG STORY SHORT...ISOLATED SHOWERS ARE POSSIBLE
NORTH OF I-80 WITH ISOLATED TO SCATTERED SHOWERS AND A FEW STORMS
SOUTH OF I-80.
AS THE MCV SHIFTS EAST THIS EVENING...THE THREAT OF SHOWERS AND
STORMS WILL ALSO SHIFT TO LOCATIONS ALONG AND EAST OF I-55.
EXPECTING FOG TO DEVELOP OVERNIGHT AS WINDS DIMINISH AND SATURATED
AIR COOLS. SOME AREAS MAY SEE DENSE FOG...VSBY OF 1/4 A MILE OR
LESS...BUT AS OF RIGHT NOW EXPECTING MOSTLY AREAS OF FOG WITH VSBY
GREATER THAN 1/4 OF A MILE.
A SHORTWAVE TROUGH TRAVELS ACROSS WI TOMORROW WITH VORTICITY
STREAMERS PASSING OVER FAR NORTHERN IL. THINKING SCATTERED SHOWERS
AND STORMS WILL FORM ALONG THE VORT STREAMERS WITH BETTER COVERAGE
NORTH OF I-80 ESPECIALLY ALONG THE WI/IL STATE LINE. THINKING
COVERAGE WILL BE HIT OR MISS WITH PLENTY OF RAIN FREE HOURS. DID
NOT MAKE MANY CHANGES TO HIGH TEMPS MONDAY WITH COOLER AIR SINKING
IN FROM THE NORTH AND THICK CLOUD COVER. EXPECTING HIGHS AROUND 80
ALONG THE IL/WI STATE LINE AND ALONG THE LAKE WITH LOW TO MID 80S
SOUTH OF I-80.
JEE
&&
.LONG TERM...
MONDAY NIGHT THROUGH SUNDAY...
251 PM...MAIN FORECAST CONCERN IS THE CHANCE OF THUNDERSTORMS
THURSDAY NIGHT THRU FRIDAY NIGHT.
WEAK LOW PRESSURE IS EXPECTED TO BE EAST OF THE AREA AND MOVING
ACROSS THE SOUTHERN GREAT LAKES REGION MONDAY EVENING. THERE IS A
SLIGHT CHANCE OF AN EVENING SHOWER OR THUNDERSTORM BUT ANY ACTIVITY
SHOULD BE QUICKLY DIMINISHING BY MID/LATE EVENING. HIGH PRESSURE
THEN BUILDS ACROSS THE REGION TUESDAY AND WEDNESDAY. NORTHERLY
WINDS MAY BE A BIT BREEZY NEAR THE LAKE INTO NORTHWEST INDIANA
TUESDAY WITH THE CENTER OF THE HIGH STILL WEST OF THE AREA WITH
CONTINUED LIGHTER NORTHERLY WINDS ON WEDNESDAY...WITH COOLER TEMPS
AT THE LAKESHORE BOTH DAYS.
WEDNESDAY NIGHT/THURSDAY MORNING WILL BE A BIT COOLER WITH LOWS
POSSIBLY IN THE MID/UPPER 50S AWAY FROM THE URBAN AREAS. BUT AS
THE HIGH SHIFTS EAST THURSDAY...WARMER SOUTHWESTERLY FLOW WILL
RETURN WITH WINDS PERHAPS BECOMING BREEZY THURSDAY AFTERNOON.
HIGHS WILL LIKELY REBOUND INTO THE MID 80S THOUGH STILL SOME
DIFFERENCES REGARDING HOW MUCH WARMER TEMPS COULD BECOME.
DIFFERENCES BEGIN TO SHOW UP FRIDAY AND FRIDAY NIGHT WITH THE GFS
BRINGING A FRONTAL BOUNDARY ACROSS THE AREA FRIDAY AFTERNOON/
EVENING WHILE THE ECMWF KEEPS THIS FRONT NORTH OF THE CWA. A
LITTLE TOO EARLY TO DETERMINE SPECIFICS BUT GRADIENT APPEARS
LIGHT ENOUGH THAT A LAKE BREEZE IS POSSIBLE FRIDAY AFTERNOON.
PRECIP CHANCES WILL LIKELY DEPEND ON HOW MUCH OF THE FRONTAL
BOUNDARY REACHES THE AREA. HAVE LOW CHANCE POPS FOR NOW...BUT
CONFIDENCE IS FAIRLY LOW. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* EAST WINDS UNDER 8KT TODAY.
* LOWERING CEILINGS THROUGH TONIGHT...BECOMING WIDESPREAD MVFR
WITH PERIODS OF IFR. VLIFR ALSO POSSIBLE.
* ISOLATED THUNDER CHANCE LATE MONDAY AFTERNOON.
MM
//DISCUSSION...UPDATED 18Z...
RADAR AND OBSERVATION TRENDS INDICATE IMPROVED VSBY AND CEILINGS
FOR THE REMAINDER OF THE AFTERNOON AS A WEAKENING THUNDERSTORM
COMPLEX PASSES/DIES NEAR IND. SOME SITES IN WI CONTINUE TO
INDICATE MVFR CIGS WHICH MAY BRIEFLY SNEAK INTO THE TAF SITES.
AS LOW PRESSURE CONTINUES TO PASS SOUTH AND EAST OF THE
AREA...WINDS WILL REMAIN EAST...TURNING MORE NORTHERLY MONDAY.
REMNANT LOW LEVEL MOISTURE AND A TEMPERATURE INVERSION WILL KEEP
FOG LIKELY FOR TONIGHT. MODEL CONSENSUS INDICATES IFR IS LIKELY
WITH VLIFR ALSO POSSIBLE. IMPROVEMENTS WILL START AFTER SUNRISE
MONDAY...BUT VFR CONDITIONS ARE NOT EXPECTED UNTIL LATE MORNING.
THUNDER CHANCES REMAIN QUITE LOW FOR MONDAY...DEPENDING ON THE
DEGREE OF HEATING TOMORROW AND THE DEVELOPMENT OF A FORCING
MECHANISM. STILL NOT OUT OF THE QUESTION THOUGH.
MM
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH ON WINDS.
* HIGH ON MVFR OVERNIGHT...MEDIUM ON IFR...LOW ON VLIFR.
* LOW ON THUNDER CHANCES MONDAY.
MM
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...SLIGHT CHANCE OF THUNDERSTORMS EARLY.
TUESDAY...VFR.
WEDNESDAY...VFR.
THURSDAY...VFR.
FRIDAY...CHANCE OF THUNDERSTORMS.
SATURDAY...VFR.
RODRIGUEZ
&&
.MARINE...
251 PM...LOW PRESSURE OVER NORTHERN ONTARIO WILL MOVE INTO QUEBEC
BY MONDAY EVENING. A TRAILING COLD FRONT WILL MOVE ACROSS THE LAKE
LATE TONIGHT INTO MONDAY MORNING SHIFTING WINDS NORTHERLY. ANOTHER
WEAK LOW WILL MOVE SOUTH OF THE LAKE MONDAY AFTERNOON AS HIGH
PRESSURE BUILDS INTO THE NORTHERN PLAINS. THE GRADIENT WILL
TIGHTEN BETWEEN THESE TWO FEATURES WITH NORTHERLY WINDS INCREASING
TO 15-25 KTS BY TUESDAY MORNING. AS THE HIGH MOVES EAST...THESE
NORTHERLY WINDS WILL SLOWLY DIMINISH TUESDAY NIGHT INTO WEDNESDAY.
WINDS WILL SHIFT TO THE SOUTHWEST WEDNESDAY NIGHT AS THE HIGH
SETTLES SOUTHEAST OF THE LAKE AND DEPENDING ON HOW STRONG THE
GRADIENT BECOMES...SPEEDS MAY INCREASE INTO THE 15-25KT RANGE
THURSDAY INTO THURSDAY NIGHT. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
221 PM CDT SUN AUG 9 2015
.SHORT TERM...
219 PM CDT
THROUGH MONDAY...
THINKING THIS AFTERNOON AND EVENING WILL BE RELATIVELY QUIET AND
POSSIBLY QUIETER THAN WHAT IS CURRENTLY FORECAST. STRAY SHOWERS ARE
OUT OVER THE LAKE AND SOUTH OF I-80 NEAR OTTAWA AND OVER NW
INDIANA. THE MCV FROM THIS MORNING/S COMPLEX IS SPINNING OVER
WESTERN MO AND SOUTHERN IL BASED ON SATELLITE DATA WITH NEW
CONVECTION FIRING OVER NORTHERN MO. THE LATEST RAP ANALYSIS
INDICATES THERE IS ABOUT 500 J/KG OF CAPE OVER THE FAR SOUTHERN
CWA WITH LITTLE TO NO CAPE OVER THE REST OF THE CWA.
GUIDANCE IS STRUGGLING WITH WHERE CONVECTION WILL FIRE GOING INTO
THIS AFTN AND HAVE LOW CONFIDENCE IN THE EXACT DETAILS MYSELF.
THINKING THE MAJORITY OF CONVECTION WILL OCCUR TO THE WEST AND SOUTH
OF THE CWA...BUT CANNOT RULE OUT A FEW SHOWERS AND/OR STORMS AS THE
MCV SHIFTS EAST OVER SOUTHERN IL. LOWERED PRECIP CHANCES INTO THE
CHANCE RANGE BELOW 50% AT BEST WITH THE HIGHEST VALUES SOUTH OF I-
80. WHILE STORMS MAY PRODUCE HEAVY DOWNPOURS AND A GUST OF
WIND...SEVERE WEATHER IS NOT EXPECTED. ONCE AGAIN...AREAS NORTH OF
I-88 MAY END UP BEING DRY BUT DID NOT HAVE ENOUGH CONFIDENCE TO GO
DRY AT THIS TIME. LONG STORY SHORT...ISOLATED SHOWERS ARE POSSIBLE
NORTH OF I-80 WITH ISOLATED TO SCATTERED SHOWERS AND A FEW STORMS
SOUTH OF I-80.
AS THE MCV SHIFTS EAST THIS EVENING...THE THREAT OF SHOWERS AND
STORMS WILL ALSO SHIFT TO LOCATIONS ALONG AND EAST OF I-55.
EXPECTING FOG TO DEVELOP OVERNIGHT AS WINDS DIMINISH AND SATURATED
AIR COOLS. SOME AREAS MAY SEE DENSE FOG...VSBY OF 1/4 A MILE OR
LESS...BUT AS OF RIGHT NOW EXPECTING MOSTLY AREAS OF FOG WITH VSBY
GREATER THAN 1/4 OF A MILE.
A SHORTWAVE TROUGH TRAVELS ACROSS WI TOMORROW WITH VORTICITY
STREAMERS PASSING OVER FAR NORTHERN IL. THINKING SCATTERED SHOWERS
AND STORMS WILL FORM ALONG THE VORT STREAMERS WITH BETTER COVERAGE
NORTH OF I-80 ESPECIALLY ALONG THE WI/IL STATE LINE. THINKING
COVERAGE WILL BE HIT OR MISS WITH PLENTY OF RAIN FREE HOURS. DID
NOT MAKE MANY CHANGES TO HIGH TEMPS MONDAY WITH COOLER AIR SINKING
IN FROM THE NORTH AND THICK CLOUD COVER. EXPECTING HIGHS AROUND 80
ALONG THE IL/WI STATE LINE AND ALONG THE LAKE WITH LOW TO MID 80S
SOUTH OF I-80.
JEE
&&
.LONG TERM...
ONE LAST HOORAH AS THE UPPER LOW IN THE CANADIAN PRAIRIES LIFTS
TOWARD HUDSON BAY...OPENING THE DOOR FOR ONE LAST SHORTWAVE IN
NORTHWEST FLOW ALOFT TO MOVE THROUGH WISCONSIN COUPLED WITH
ADDITIONAL FAST MOVING WAVES COMING FROM THE PACIFIC. SLIGHTLY
BETTER LAPSE RATES ALOFT COUPLED WITH A SOUTHWARD MOVING COLD FRONT
WOULD SUGGEST THE POTENTIAL FOR SOME SCATTERED SHOWERS AND
THUNDERSTORMS MONDAY AFTERNOON/EARLY EVENING. SCATTERED MENTION DUE
TO THE TIMING/MOISTURE ISSUES AND THE FACT THE BETTER FORCING SWINGS
BY TO THE NORTH.
THE STRONG UPPER DISTURBANCE SOUTH OF HUDSON BAY WILL MOVE SOUTHEAST
ON MONDAY NIGHT INTO TUESDAY AND HIGH PRESSURE BUILDS IN FOR SEVERAL
DAYS. A HIGHLY AMPLIFIED PATTERN WILL SLOW THE PROGRESSION OF
SHORTWAVE ACTIVITY. WE WILL LARGELY BE UNDER THE INFLUENCE OF A
COMBINATION OF THE WESTERN U.S. RIDGE SUPPLYING THE DRY WEATHER AND
THE COOLING INFLUENCE OF NORTHWEST FLOW ON THE BACK SIDE OF THE
EASTERN U.S TROUGH. HIGHS WILL BE SLIGHTLY BELOW NORMAL WITH
COMFORTABLE HUMIDITY AND DECENT SUNSHINE. MOISTURE RETURN IS LACKING
UNTIL LATER IN THE WEEK WHEN A FRONTAL BOUNDARY DROPS THROUGH
THURSDAY NIGHT INTO FRIDAY. THIS WILL BE OUR NEXT CHANCE FOR SHOWERS
AND THUNDERSTORMS.
KMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* EAST WINDS UNDER 8KT TODAY.
* LOWERING CEILINGS THROUGH TONIGHT...BECOMING WIDESPREAD MVFR
WITH PERIODS OF IFR. VLIFR ALSO POSSIBLE.
* ISOLATED THUNDER CHANCE LATE MONDAY AFTERNOON.
MM
//DISCUSSION...UPDATED 18Z...
RADAR AND OBSERVATION TRENDS INDICATE IMPROVED VSBY AND CEILINGS
FOR THE REMAINDER OF THE AFTERNOON AS A WEAKENING THUNDERSTORM
COMPLEX PASSES/DIES NEAR IND. SOME SITES IN WI CONTINUE TO
INDICATE MVFR CIGS WHICH MAY BRIEFLY SNEAK INTO THE TAF SITES.
AS LOW PRESSURE CONTINUES TO PASS SOUTH AND EAST OF THE
AREA...WINDS WILL REMAIN EAST...TURNING MORE NORTHERLY MONDAY.
REMNANT LOW LEVEL MOISTURE AND A TEMPERATURE INVERSION WILL KEEP
FOG LIKELY FOR TONIGHT. MODEL CONSENSUS INDICATES IFR IS LIKELY
WITH VLIFR ALSO POSSIBLE. IMPROVEMENTS WILL START AFTER SUNRISE
MONDAY...BUT VFR CONDITIONS ARE NOT EXPECTED UNTIL LATE MORNING.
THUNDER CHANCES REMAIN QUITE LOW FOR MONDAY...DEPENDING ON THE
DEGREE OF HEATING TOMORROW AND THE DEVELOPMENT OF A FORCING
MECHANISM. STILL NOT OUT OF THE QUESTION THOUGH.
MM
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH ON WINDS.
* HIGH ON MVFR OVERNIGHT...MEDIUM ON IFR...LOW ON VLIFR.
* LOW ON THUNDER CHANCES MONDAY.
MM
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...SLIGHT CHANCE OF THUNDERSTORMS EARLY.
TUESDAY...VFR.
WEDNESDAY...VFR.
THURSDAY...VFR.
FRIDAY...CHANCE OF THUNDERSTORMS.
SATURDAY...VFR.
RODRIGUEZ
&&
.MARINE...
230 AM CDT
HIGHLY VARIABLE WIND FIELD ACROSS THE LAKE THIS MORNING AS A
WEAKER SURFACE PATTERN IN PLACE...WITH HIGH PRESSURE SITUATED TO
THE EAST AND NORTHEAST. THESE VARIABLE WINDS WILL LIKELY PERSIST
ACROSS THE NORTHERN HALF OF THE LAKE TODAY WHILE THE SOUTHERN END
BECOMES MORE SOUTHERLY THIS MORNING...AS LOW PRESSURE SLOWLY MOVES
EAST TOWARDS THE REGION. AS THIS THIS LOW CONTINUES EAST NORTHEAST
TO THE SOUTHERN END OF THE LAKE AND A SEPARATE LOW OVER ONTARIO
MOVES EAST TO HUDSON BAY TONIGHT...WINDS WILL LIKELY CONTINUE TO
BE VARIABLE ACROSS THE LAKE. HOWEVER...IT DOES APPEAR THAT SPEEDS
WILL STAY ON THE LIGHTER SIDE THROUGH THIS PERIOD. THIS LOW WILL
THEN MOVE TO THE EASTERN LAKES MONDAY INTO MONDAY NIGHT AS HIGH
PRESSURE TO THE NORTHWEST BEGINS SPREADING SOUTHEAST...WITH
NORTHERLY WINDS SETTING UP ACROSS THE ENTIRE LAKE. AS THE SURFACE
GRADIENT TIGHTENS UP OVER THE LAKE LATE MONDAY AND MONDAY
NIGHT...NORTHERLY SPEEDS WILL BEGIN TO INCREASE. THIS INCREASING
TREND WITH THE NORTHERLY WINDS CONTINUES TUESDAY WITH 15 TO 25 KT
WINDS BECOMING LIKELY DURING THIS TIME.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1256 PM CDT SUN AUG 9 2015
.UPDATE...
959 AM CDT
THE CONVECTIVE COMPLEX OVERHEAD IS QUICKLY WARMING ALOFT THIS
MORNING WITH THE SYSTEM CONTINUING TO REFOCUS OVER CENTRAL IL.
RAIN HAS STRUGGLED TO SPREAD NORTH OF A ROCHELLE TO JOLIET TO DE
MOTTE INDIANA LINE THIS MORNING DESPITE A SURGING GRAVITY WAVE
ESQ BOUNDARY SHIFTING NORTHEAST EARLIER THIS MORNING. THE
BOUNDARY HAS WEAKENED CONSIDERABLY AND AREAS ALONG THE
AFOREMENTIONED LINE ARE JUST NOW POSSIBLY SEEING SOME SPRINKLES.
IN GENERAL THE RAIN WILL GRADUALLY WEAKEN AS IT SHIFTS EAST WITH
THE MAJORITY OF RAIN FALLING SOUTH OF A MENDOTA TO JOLIET TO DE
MOTTE INDIANA LINE. FAR NORTHEAST IL INCLUDING THE CHICAGO METRO
MAY SEE SOME SPRINKLES TO A LIGHT RAIN SHOWER CLOSER TO NOON...BUT
NOTHING OVERLY SIGNIFICANT. ISOLATED EMBEDDED THUNDERSTORMS ARE
ALSO POSSIBLE SOUTH OF THE MENDOTA...JOLIET...DE MOTTE LINE
THROUGH THE MORNING BUT NO SEVERE WEATHER IS EXPECTED.
GUIDANCE IS REALLY STRUGGLING WITH THE CONVECTIVE EVOLUTION GOING
INTO THIS AFTERNOON WITH THE RAP AND HRRR LOOKING THE MOST
REASONABLE THUS FAR. MADE MINOR TWEAKS TO PRECIP CHANCES THROUGH
THIS AFTN WITH THE FOCUS FOR EITHER FESTERING RAIN AND STORMS OR
SOME REDEVELOPMENT ALONG AND SOUTH OF I-80. KEPT A CHANCE OF
SHOWERS AND STORMS ACROSS THE CWA THIS AFTERNOON AS CONFIDENCE IS
LOW AS TO HOW FAR NORTH ACTIVITY WILL CONTINUE TO FESTER. WITH THE
MCV OVER CENTRAL IL...HAVE MUCH HIGHER CONFIDENCE IN AREAS SOUTH
OF I-80 SEEING THE MAJORITY OF ACTIVITY. DEBATED GOING DRY NORTH
OF I-88 THIS AFTN...BUT CANNOT RULE OUT A FEW SHOWERS AND PERHAPS
A STORM.
AS FAR AS STRONG TO SEVERE STORMS...CANNOT RULE OUT ONE OR TWO
STRONG STORMS...BUT THINKING WE WILL STRUGGLE TO RECOVER THIS AFTN
GIVEN THE THICK CLOUD COVER AND LINGERING RAIN. AGREE WITH THE
MARGINAL RISK FROM SPC. THINKING THE AREA OF CONCERN WOULD BE
SOUTH OF A STREATOR TO DE MOTTE LINE WITH THE BEST ACTIVITY WELL
SOUTH OF THE CWA OVER CENTRAL IL MUCH CLOSER TO THE MCV.
JEE
&&
.SHORT TERM...
358 AM CDT
THROUGH SUNDAY NIGHT...
TWO COMPLEXES OF SHOWERS AND THUNDERSTORMS ARE ONGOING EARLY THIS
MORNING THOUGH HAVE GENERALLY BEEN MERGING INTO ONE TO SOME
DEGREE...THOUGH STILL LOOK TO BE DISTINCT BASED ON THE LIGHTNING
AXES IN CENTRAL IOWA EXTENDING INTO WESTERN ILLINOIS..AND A
SEPARATE AREA IN SOUTHERN IOWA INTO NORTHERN MISSOURI.
AT THE MOMENT...THE NORTHERN EXTENT OF THE NORTHERN BATCH ENTERING
NW ILLINOIS IS IN A LESS HOSPITABLE ENVIRONMENT FOR CONTINUED FORWARD
PROPAGATION AND GROWTH AND BEING DRIVEN MORE SO FROM AN UPPER
LEVEL SHORTWAVE RIDING THE NORTHERN FRINGE OF THE RIDGE AXIS. THE
DEPTH OF THESE SHOWERS IS NOT IMPRESSIVE...AND EROSION ON THIS
ACTIVITY CONTINUES WITH JUST SOME LIGHT RAIN/SPRINKLES...WITH THE BEST
CHANCE FOR EROSION TO CONTINUE WILL BE IN NORTHERN ILLINOIS WITH
THE DRIEST AIRMASS AND MOST REMOVED FROM THE MAIN LOWER LEVEL
FORCING/BAROCLINIC ZONE. THE LLJ IS FOCUSED MORE-SO INTO THE
SOUTHERN MOST STORMS WHICH HAVE THE UPPER ENERGY SUPPORT COMBINED
WITH A BETTER THERMODYNAMIC ENVIRONMENT. LASALLE/LIVINGSTON/LEE
COUNTIES OR ON THE EASTERN EXTENT OF THE BETTER LLJ FORCING WHERE
MORE ORGANIZED AND SUSTAINED DEVELOPMENT WILL CONTINUE IN THE
COMING HOURS. MORE ROBUST DEVELOPMENT IS OCCURRING ON THE BACK
SIDE OF THIS COMPLEX WHERE A PORTION OF THE STRONGER LLJ WHICH
FEEDING THE SOUTHERN SYSTEM IS ABLE TO ADVECT NORTH INTO THE
NORTHERN STREAM ACTIVITY.
WITH THIS COMPLEX SETUP AT THE MOMENT...CONFIDENCE ON THE EVOLUTION
IS NOT AS HIGH AS I WOULD LIKE IT TO BE WITH MODELS STRUGGLING WITH
INITIALIZATIONS. THERE IS LITTLE TO SUGGEST THAT THESE SHOWERS AND
STORMS WON`T CONTINUE EASTWARD ONCE THE SHORTWAVE DRIVING IT
MOVES RIGHT ON THROUGH NE ILLINOIS...BUT DO PREFER THE HRRR
SOLUTION WHICH JUST BRINGS SOME LIGHTER RAIN NORTH (AND POSSIBLY
DRY IN FAR NORTH/NE ILLINOIS) AND FOCUSES ACTIVITY SOUTH THIS
MORNING. THE LLJ WHICH IS STILL STRONGEST IA BASED ON AREA VWPS
WILL BECOME ORIENTED SW-NE WITH THE MOISTURE CONVERGENCE AXIS
POINTED RIGHT AT US. THE INSTABILITY AXIS LOOKS TO BE POSITIONED
ACROSS THE CENTER OF THE CWA WHICH WILL LIKELY KEEP THE NORTHERN
AREAS JUST RAIN...WHEREAS POINTS SOUTH WILL AT LEAST SEE EMBEDDED
THUNDER DESPITE MARGINAL MID LEVEL LAPSE RATES. PRECIPITABLE WATER
VALUES ARE QUITE AN UPTICK THIS MORNING...SO THE I-80 SOUTHWARD
CORRIDOR MAY SEE SOME 1" PER HOUR RATES IN AN EFFICIENT
ENVIRONMENT.
SOME UNCERTAINTIES ON REMAINING FORCING IN THE AFTERNOON...AND
POTENTIAL FOR MORNING ACTIVITY TO KEEP ANY OUTFLOW FOCUSED SOUTH
OF THE AREA. THE LOCATION OF THE SURFACE FRONT MAY BECOME A BIT
MORE UNCERTAIN AFTER THESE STORMS LAY OUT ANY OUTFLOW. THE AIR
MASS WILL BE MOIST...THERE WILL BE SOME SHEAR AROUND...AND A LOW
LEVEL BOUNDARY...WHICH PRESENTS SOME CONCERNS WITH ANY ADDITIONAL
SUBTLE SHORTWAVES THAT MAY PASS THROUGH IN PROGRESSIVE WESTERLY
FLOW. HI-RES GUIDANCE IS RE-GENERATING STORMS IN IOWA THIS
AFTERNOON...AND DEPENDING ON WHERE THE SURFACE BOUNDARY ENDS UP
COULD POSE A MARGINAL SVR THREAT AS OUTLINED IN THE DAY 1 OUTLOOK
AND WILL NEED TO BE IRONED OUT BY THE DAY SHIFT.
AFTER WHAT COULD BE AN AFTERNOON LULL..THE SURFACE LOW TO OUR SOUTH
LIFTS NORTHEASTWARD SUNDAY NIGHT INTO EARLY MONDAY. ANOTHER
SHORTWAVE APPROACHES WITH THE INVERTED TROUGH AXIS POINTED RIGHT
OVER NORTHEAST ILLINOIS TONIGHT FOR POTENTIALLY A REINVIGORATION OF
SHOWERS...BUT STILL SOME UNCERTAINTY ON COVERAGE AT THIS POINT.
KMD
&&
.LONG TERM...
ONE LAST HOORAH AS THE UPPER LOW IN THE CANADIAN PRAIRIES LIFTS
TOWARD HUDSON BAY...OPENING THE DOOR FOR ONE LAST SHORTWAVE IN
NORTHWEST FLOW ALOFT TO MOVE THROUGH WISCONSIN COUPLED WITH
ADDITIONAL FAST MOVING WAVES COMING FROM THE PACIFIC. SLIGHTLY
BETTER LAPSE RATES ALOFT COUPLED WITH A SOUTHWARD MOVING COLD FRONT
WOULD SUGGEST THE POTENTIAL FOR SOME SCATTERED SHOWERS AND
THUNDERSTORMS MONDAY AFTERNOON/EARLY EVENING. SCATTERED MENTION DUE
TO THE TIMING/MOISTURE ISSUES AND THE FACT THE BETTER FORCING SWINGS
BY TO THE NORTH.
THE STRONG UPPER DISTURBANCE SOUTH OF HUDSON BAY WILL MOVE SOUTHEAST
ON MONDAY NIGHT INTO TUESDAY AND HIGH PRESSURE BUILDS IN FOR SEVERAL
DAYS. A HIGHLY AMPLIFIED PATTERN WILL SLOW THE PROGRESSION OF
SHORTWAVE ACTIVITY. WE WILL LARGELY BE UNDER THE INFLUENCE OF A
COMBINATION OF THE WESTERN U.S. RIDGE SUPPLYING THE DRY WEATHER AND
THE COOLING INFLUENCE OF NORTHWEST FLOW ON THE BACK SIDE OF THE
EASTERN U.S TROUGH. HIGHS WILL BE SLIGHTLY BELOW NORMAL WITH
COMFORTABLE HUMIDITY AND DECENT SUNSHINE. MOISTURE RETURN IS LACKING
UNTIL LATER IN THE WEEK WHEN A FRONTAL BOUNDARY DROPS THROUGH
THURSDAY NIGHT INTO FRIDAY. THIS WILL BE OUR NEXT CHANCE FOR SHOWERS
AND THUNDERSTORMS.
KMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* EAST WINDS UNDER 8KT TODAY.
* LOWERING CEILINGS THROUGH TONIGHT...BECOMING WIDESPREAD MVFR
WITH PERIODS OF IFR. VLIFR ALSO POSSIBLE.
* ISOLATED THUNDER CHANCE LATE MONDAY AFTERNOON.
MM
//DISCUSSION...UPDATED 18Z...
RADAR AND OBSERVATION TRENDS INDICATE IMPROVED VSBY AND CEILINGS
FOR THE REMAINDER OF THE AFTERNOON AS A WEAKENING THUNDERSTORM
COMPLEX PASSES/DIES NEAR IND. SOME SITES IN WI CONTINUE TO
INDICATE MVFR CIGS WHICH MAY BRIEFLY SNEAK INTO THE TAF SITES.
AS LOW PRESSURE CONTINUES TO PASS SOUTH AND EAST OF THE
AREA...WINDS WILL REMAIN EAST...TURNING MORE NORTHERLY MONDAY.
REMNANT LOW LEVEL MOISTURE AND A TEMPERATURE INVERSION WILL KEEP
FOG LIKELY FOR TONIGHT. MODEL CONSENSUS INDICATES IFR IS LIKELY
WITH VLIFR ALSO POSSIBLE. IMPROVEMENTS WILL START AFTER SUNRISE
MONDAY...BUT VFR CONDITIONS ARE NOT EXPECTED UNTIL LATE MORNING.
THUNDER CHANCES REMAIN QUITE LOW FOR MONDAY...DEPENDING ON THE
DEGREE OF HEATING TOMORROW AND THE DEVELOPMENT OF A FORCING
MECHANISM. STILL NOT OUT OF THE QUESTION THOUGH.
MM
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH ON WINDS.
* HIGH ON MVFR OVERNIGHT...MEDIUM ON IFR...LOW ON VLIFR.
* LOW ON THUNDER CHANCES MONDAY.
MM
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...SLIGHT CHANCE OF THUNDERSTORMS EARLY.
TUESDAY...VFR.
WEDNESDAY...VFR.
THURSDAY...VFR.
FRIDAY...CHANCE OF THUNDERSTORMS.
SATURDAY...VFR.
RODRIGUEZ
&&
.MARINE...
230 AM CDT
HIGHLY VARIABLE WIND FIELD ACROSS THE LAKE THIS MORNING AS A
WEAKER SURFACE PATTERN IN PLACE...WITH HIGH PRESSURE SITUATED TO
THE EAST AND NORTHEAST. THESE VARIABLE WINDS WILL LIKELY PERSIST
ACROSS THE NORTHERN HALF OF THE LAKE TODAY WHILE THE SOUTHERN END
BECOMES MORE SOUTHERLY THIS MORNING...AS LOW PRESSURE SLOWLY MOVES
EAST TOWARDS THE REGION. AS THIS THIS LOW CONTINUES EAST NORTHEAST
TO THE SOUTHERN END OF THE LAKE AND A SEPARATE LOW OVER ONTARIO
MOVES EAST TO HUDSON BAY TONIGHT...WINDS WILL LIKELY CONTINUE TO
BE VARIABLE ACROSS THE LAKE. HOWEVER...IT DOES APPEAR THAT SPEEDS
WILL STAY ON THE LIGHTER SIDE THROUGH THIS PERIOD. THIS LOW WILL
THEN MOVE TO THE EASTERN LAKES MONDAY INTO MONDAY NIGHT AS HIGH
PRESSURE TO THE NORTHWEST BEGINS SPREADING SOUTHEAST...WITH
NORTHERLY WINDS SETTING UP ACROSS THE ENTIRE LAKE. AS THE SURFACE
GRADIENT TIGHTENS UP OVER THE LAKE LATE MONDAY AND MONDAY
NIGHT...NORTHERLY SPEEDS WILL BEGIN TO INCREASE. THIS INCREASING
TREND WITH THE NORTHERLY WINDS CONTINUES TUESDAY WITH 15 TO 25 KT
WINDS BECOMING LIKELY DURING THIS TIME.
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:
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AREA FORECAST DISCUSSION
NWS LINCOLN IL
1232 PM CDT SUN AUG 9 2015
.UPDATE...
ISSUED AT 1032 AM CDT SUN AUG 9 2015
MCS CONTINUES TO MOVE EAST AND BASED ON RADAR AND SATELLITE
TRENDS...SHOULD CONTINUE TO DECAY AS WELL. STRONGEST PART OF THE
STORM ALSO CONTINUES TO TRANSLATE SOUTH AND WILL MOVE ACROSS
PORTIONS OF SOUTHEAST ILLINOIS THIS AFTERNOON. ONCE THIS MOVES
THROUGH BY EARLY THIS AFTERNOON...SKIES SHOULD BECOME PARTLY SUNNY
WITH MAYBE SOME SCATTERED SHOWERS. WILL BE MAKING SOME ADJUSTMENTS
TO THE GOING FORECAST TO ACCOUNT FOR THIS TREND IN PCPN AND CLOUD
COVER. THIS DECAYING MCS WILL ALSO ACT TO PUSH THE SURFACE
BOUNDARY LITTLE FURTHER SOUTH FOR REMAINDER OF THE AFTERNOON.
UPDATE WILL BE OUT SHORTLY.
&&
.SHORT TERM...(TODAY)
ISSUED AT 304 AM CDT SUN AUG 9 2015
07Z/2AM SURFACE ANALYSIS SHOWS 1008MB LOW OVER NORTHEAST
KANSAS...WITH WEAK FRONTAL BOUNDARY EXTENDING ACROSS NORTHERN
MISSOURI INTO CENTRAL ILLINOIS. SEVERAL CLUSTERS OF THUNDERSTORMS
HAVE DEVELOPED JUST NORTH OF THE BOUNDARY NEAR THE LOW...AIDED BY A
35-40KT 850MB JET AS EVIDENCED BY REGIONAL VWP NETWORK. STORMS WERE
SLIGHTLY SLOWER TO DEVELOP THAN PREVIOUSLY THOUGHT...SO THEIR
EASTWARD PROGRESSION HAS BEEN DELAYED AS WELL. AS LOW-LEVEL JET
VEERS...STORMS WILL BEGIN TO DEVELOP/PROPAGATE EASTWARD ALONG THE
BOUNDARY AND WILL SPILL INTO WEST-CENTRAL ILLINOIS BETWEEN 09Z AND
12Z. THANKS TO AN INFLOW OF RICH LOW-LEVEL MOISTURE RESULTING IN
PRECIPITABLE WATER VALUES INCREASING TO OVER 2 INCHES...LOCALLY
HEAVY RAINFALL WILL BE LIKELY AS THE MCS ARRIVES. HIGHEST POPS WILL
BE FOCUSED ALONG/WEST OF I-55 WHERE RAINFALL AMOUNTS OF 1 TO 1.50
WILL BE LIKELY. AS MCS UNDERGOES DIURNAL WEAKENING...RAIN TOTALS
WILL STEADILY DECREASE FURTHER EAST...WITH ONLY AROUND 0.25 EXPECTED
NEAR THE INDIANA BORDER. BASED ON POSITION OF FRONTAL
BOUNDARY...THINK THE FAR SOUTHEAST KILX CWA ALONG/SOUTH OF I-70 WILL
SEE LITTLE OR NO RAIN FROM THIS SYSTEM. DUE TO PRECIP AND EXTENSIVE
CLOUD COVER FROM THE MORNING MCS...HIGH TEMPS WILL BE TRICKY TODAY.
HAVE GONE WITH AFTERNOON HIGHS IN THE LOWER 80S ACROSS THE NORTHERN
HALF OF THE CWA...WITH MIDDLE TO UPPER 80S FAR SOUTHEAST.
.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 304 AM CDT SUN AUG 9 2015
ADDITIONAL CONVECTION MAY DEVELOP ALONG THE OUTFLOW BOUNDARY LEFT
BEHIND BY THE MORNING MCS...HOWEVER EXACT POSITION OF THAT BOUNDARY
REMAINS IN QUESTION. MODEL CONSENSUS SEEMS TO BE FOCUSING
ALONG/SOUTH OF I-70 THIS EVENING...SO HAVE CARRIED LIKELY POPS
ACROSS THIS AREA. FURTHER NORTH...HAVE GONE WITH CHANCE POPS ACROSS
THE REMAINDER OF THE CWA THROUGH THE EVENING...FOLLOWED BY MAINLY
DRY CONDITIONS AFTER MIDNIGHT. DESPITE FRONTAL BOUNDARY DROPPING
SOUTH OF THE AREA...HAVE HUNG ON TO SLIGHT CHANCE POPS MONDAY AND
MONDAY EVENING DUE TO A TRAILING 500MB WAVE AND WEAK SURFACE TROUGH.
LAPSE RATES APPEAR TO BECOME STEEP ENOUGH TO SUPPORT AT LEAST
ISOLATED SHOWERS/THUNDER...PRIMARILY DURING PEAK HEATING. ONCE
DAYTIME INSTABILITY IS LOST...CONVECTION WILL QUICKLY DISSIPATE
AFTER SUNSET.
AFTER THAT...PRONOUNCED UPPER RIDGE WILL BUILD OVER THE CENTRAL
CONUS INTO SOUTHERN CANADA FOR THE MIDDLE AND END OF THE WEEK.
DOWNSTREAM TROUGHING ACROSS THE GREAT LAKES/OHIO RIVER VALLEY WILL
ENSURE A COOL/DRY PATTERN FOR CENTRAL ILLINOIS TUESDAY THROUGH
THURSDAY. ONLY POTENTIAL FLY-IN-THE-OINTMENT WILL COME INTO PLAY ON
FRIDAY AS A WEAK COLD FRONT DROPS TOWARD THE REGION. BOTH THE GFS
AND ECMWF BRING THE BOUNDARY INTO NORTHERN ILLINOIS BY FRIDAY
AFTERNOON...THEN WASH IT OUT ACROSS CENTRAL ILLINOIS FRIDAY NIGHT
INTO SATURDAY AS UPPER HEIGHTS RISE ACROSS THE AREA. WILL CARRY
SLIGHT CHANCE POPS ALONG/NORTH OF I-74 DURING THE DAY FRIDAY...BUT
WILL RETURN TO A DRY FORECAST FRIDAY NIGHT INTO SATURDAY ACCORDINGLY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1232 PM CDT SUN AUG 9 2015
MCS HAS DECAYED AND MOVED EAST OF THE TAF SITES LATE THIS MORNING.
THIS HAS PUSHED THE EFFECTIVE FRONT SOUTH OF THE TAFS AND CURRENT
THINKING...WHICH IS SUPPORTED BY THE CURRENT HRRR MODEL
RUN...SHOWS ALL PCPN SHOULD BE SOUTH OF THE TAF SITES THIS
AFTERNOON AND TONIGHT. ONLY CONCERN IS WITH WINDS BECOMING
LIGHTER AND SKIES BECOMING MOSTLY CLEAR...WITH ALL THE MOISTURE
HAD THIS MORNING...BELIEVE FOG WILL BE AN ISSUE THIS EVENING AND
INTO THE OVERNIGHT HOURS. SO HAVE INCLUDED MVFR CONDITIONS THIS
EVENING AND THEN GOING WITH IFR CONDITIONS DURING THE OVERNIGHT.
WINDS WILL BE SOUTHERLY REMAINDER OF THE AFTERNOON AND THEN BECOME
LIGHT AND VARIABLE THIS EVENING AND OVERNIGHT.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AUTEN
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...AUTEN
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1101 AM CDT SUN AUG 9 2015
.UPDATE...
959 AM CDT
THE CONVECTIVE COMPLEX OVERHEAD IS QUICKLY WARMING ALOFT THIS
MORNING WITH THE SYSTEM CONTINUING TO REFOCUS OVER CENTRAL IL.
RAIN HAS STRUGGLED TO SPREAD NORTH OF A ROCHELLE TO JOLIET TO DE
MOTTE INDIANA LINE THIS MORNING DESPITE A SURGING GRAVITY WAVE
ESQ BOUNDARY SHIFTING NORTHEAST EARLIER THIS MORNING. THE
BOUNDARY HAS WEAKENED CONSIDERABLY AND AREAS ALONG THE
AFOREMENTIONED LINE ARE JUST NOW POSSIBLY SEEING SOME SPRINKLES.
IN GENERAL THE RAIN WILL GRADUALLY WEAKEN AS IT SHIFTS EAST WITH
THE MAJORITY OF RAIN FALLING SOUTH OF A MENDOTA TO JOLIET TO DE
MOTTE INDIANA LINE. FAR NORTHEAST IL INCLUDING THE CHICAGO METRO
MAY SEE SOME SPRINKLES TO A LIGHT RAIN SHOWER CLOSER TO NOON...BUT
NOTHING OVERLY SIGNIFICANT. ISOLATED EMBEDDED THUNDERSTORMS ARE
ALSO POSSIBLE SOUTH OF THE MENDOTA...JOLIET...DE MOTTE LINE
THROUGH THE MORNING BUT NO SEVERE WEATHER IS EXPECTED.
GUIDANCE IS REALLY STRUGGLING WITH THE CONVECTIVE EVOLUTION GOING
INTO THIS AFTERNOON WITH THE RAP AND HRRR LOOKING THE MOST
REASONABLE THUS FAR. MADE MINOR TWEAKS TO PRECIP CHANCES THROUGH
THIS AFTN WITH THE FOCUS FOR EITHER FESTERING RAIN AND STORMS OR
SOME REDEVELOPMENT ALONG AND SOUTH OF I-80. KEPT A CHANCE OF
SHOWERS AND STORMS ACROSS THE CWA THIS AFTERNOON AS CONFIDENCE IS
LOW AS TO HOW FAR NORTH ACTIVITY WILL CONTINUE TO FESTER. WITH THE
MCV OVER CENTRAL IL...HAVE MUCH HIGHER CONFIDENCE IN AREAS SOUTH
OF I-80 SEEING THE MAJORITY OF ACTIVITY. DEBATED GOING DRY NORTH
OF I-88 THIS AFTN...BUT CANNOT RULE OUT A FEW SHOWERS AND PERHAPS
A STORM.
AS FAR AS STRONG TO SEVERE STORMS...CANNOT RULE OUT ONE OR TWO
STRONG STORMS...BUT THINKING WE WILL STRUGGLE TO RECOVER THIS AFTN
GIVEN THE THICK CLOUD COVER AND LINGERING RAIN. AGREE WITH THE
MARGINAL RISK FROM SPC. THINKING THE AREA OF CONCERN WOULD BE
SOUTH OF A STREATOR TO DE MOTTE LINE WITH THE BEST ACTIVITY WELL
SOUTH OF THE CWA OVER CENTRAL IL MUCH CLOSER TO THE MCV.
JEE
&&
.SHORT TERM...
358 AM CDT
THROUGH SUNDAY NIGHT...
TWO COMPLEXES OF SHOWERS AND THUNDERSTORMS ARE ONGOING EARLY THIS
MORNING THOUGH HAVE GENERALLY BEEN MERGING INTO ONE TO SOME
DEGREE...THOUGH STILL LOOK TO BE DISTINCT BASED ON THE LIGHTNING
AXES IN CENTRAL IOWA EXTENDING INTO WESTERN ILLINOIS..AND A
SEPARATE AREA IN SOUTHERN IOWA INTO NORTHERN MISSOURI.
AT THE MOMENT...THE NORTHERN EXTENT OF THE NORTHERN BATCH ENTERING
NW ILLINOIS IS IN A LESS HOSPITABLE ENVIRONMENT FOR CONTINUED FORWARD
PROPAGATION AND GROWTH AND BEING DRIVEN MORE SO FROM AN UPPER
LEVEL SHORTWAVE RIDING THE NORTHERN FRINGE OF THE RIDGE AXIS. THE
DEPTH OF THESE SHOWERS IS NOT IMPRESSIVE...AND EROSION ON THIS
ACTIVITY CONTINUES WITH JUST SOME LIGHT RAIN/SPRINKLES...WITH THE BEST
CHANCE FOR EROSION TO CONTINUE WILL BE IN NORTHERN ILLINOIS WITH
THE DRIEST AIRMASS AND MOST REMOVED FROM THE MAIN LOWER LEVEL
FORCING/BAROCLINIC ZONE. THE LLJ IS FOCUSED MORE-SO INTO THE
SOUTHERN MOST STORMS WHICH HAVE THE UPPER ENERGY SUPPORT COMBINED
WITH A BETTER THERMODYNAMIC ENVIRONMENT. LASALLE/LIVINGSTON/LEE
COUNTIES OR ON THE EASTERN EXTENT OF THE BETTER LLJ FORCING WHERE
MORE ORGANIZED AND SUSTAINED DEVELOPMENT WILL CONTINUE IN THE
COMING HOURS. MORE ROBUST DEVELOPMENT IS OCCURRING ON THE BACK
SIDE OF THIS COMPLEX WHERE A PORTION OF THE STRONGER LLJ WHICH
FEEDING THE SOUTHERN SYSTEM IS ABLE TO ADVECT NORTH INTO THE
NORTHERN STREAM ACTIVITY.
WITH THIS COMPLEX SETUP AT THE MOMENT...CONFIDENCE ON THE EVOLUTION
IS NOT AS HIGH AS I WOULD LIKE IT TO BE WITH MODELS STRUGGLING WITH
INITIALIZATIONS. THERE IS LITTLE TO SUGGEST THAT THESE SHOWERS AND
STORMS WON`T CONTINUE EASTWARD ONCE THE SHORTWAVE DRIVING IT
MOVES RIGHT ON THROUGH NE ILLINOIS...BUT DO PREFER THE HRRR
SOLUTION WHICH JUST BRINGS SOME LIGHTER RAIN NORTH (AND POSSIBLY
DRY IN FAR NORTH/NE ILLINOIS) AND FOCUSES ACTIVITY SOUTH THIS
MORNING. THE LLJ WHICH IS STILL STRONGEST IA BASED ON AREA VWPS
WILL BECOME ORIENTED SW-NE WITH THE MOISTURE CONVERGENCE AXIS
POINTED RIGHT AT US. THE INSTABILITY AXIS LOOKS TO BE POSITIONED
ACROSS THE CENTER OF THE CWA WHICH WILL LIKELY KEEP THE NORTHERN
AREAS JUST RAIN...WHEREAS POINTS SOUTH WILL AT LEAST SEE EMBEDDED
THUNDER DESPITE MARGINAL MID LEVEL LAPSE RATES. PRECIPITABLE WATER
VALUES ARE QUITE AN UPTICK THIS MORNING...SO THE I-80 SOUTHWARD
CORRIDOR MAY SEE SOME 1" PER HOUR RATES IN AN EFFICIENT
ENVIRONMENT.
SOME UNCERTAINTIES ON REMAINING FORCING IN THE AFTERNOON...AND
POTENTIAL FOR MORNING ACTIVITY TO KEEP ANY OUTFLOW FOCUSED SOUTH
OF THE AREA. THE LOCATION OF THE SURFACE FRONT MAY BECOME A BIT
MORE UNCERTAIN AFTER THESE STORMS LAY OUT ANY OUTFLOW. THE AIR
MASS WILL BE MOIST...THERE WILL BE SOME SHEAR AROUND...AND A LOW
LEVEL BOUNDARY...WHICH PRESENTS SOME CONCERNS WITH ANY ADDITIONAL
SUBTLE SHORTWAVES THAT MAY PASS THROUGH IN PROGRESSIVE WESTERLY
FLOW. HI-RES GUIDANCE IS RE-GENERATING STORMS IN IOWA THIS
AFTERNOON...AND DEPENDING ON WHERE THE SURFACE BOUNDARY ENDS UP
COULD POSE A MARGINAL SVR THREAT AS OUTLINED IN THE DAY 1 OUTLOOK
AND WILL NEED TO BE IRONED OUT BY THE DAY SHIFT.
AFTER WHAT COULD BE AN AFTERNOON LULL..THE SURFACE LOW TO OUR SOUTH
LIFTS NORTHEASTWARD SUNDAY NIGHT INTO EARLY MONDAY. ANOTHER
SHORTWAVE APPROACHES WITH THE INVERTED TROUGH AXIS POINTED RIGHT
OVER NORTHEAST ILLINOIS TONIGHT FOR POTENTIALLY A REINVIGORATION OF
SHOWERS...BUT STILL SOME UNCERTAINTY ON COVERAGE AT THIS POINT.
KMD
&&
.LONG TERM...
ONE LAST HOORAH AS THE UPPER LOW IN THE CANADIAN PRAIRIES LIFTS
TOWARD HUDSON BAY...OPENING THE DOOR FOR ONE LAST SHORTWAVE IN
NORTHWEST FLOW ALOFT TO MOVE THROUGH WISCONSIN COUPLED WITH
ADDITIONAL FAST MOVING WAVES COMING FROM THE PACIFIC. SLIGHTLY
BETTER LAPSE RATES ALOFT COUPLED WITH A SOUTHWARD MOVING COLD FRONT
WOULD SUGGEST THE POTENTIAL FOR SOME SCATTERED SHOWERS AND
THUNDERSTORMS MONDAY AFTERNOON/EARLY EVENING. SCATTERED MENTION DUE
TO THE TIMING/MOISTURE ISSUES AND THE FACT THE BETTER FORCING SWINGS
BY TO THE NORTH.
THE STRONG UPPER DISTURBANCE SOUTH OF HUDSON BAY WILL MOVE SOUTHEAST
ON MONDAY NIGHT INTO TUESDAY AND HIGH PRESSURE BUILDS IN FOR SEVERAL
DAYS. A HIGHLY AMPLIFIED PATTERN WILL SLOW THE PROGRESSION OF
SHORTWAVE ACTIVITY. WE WILL LARGELY BE UNDER THE INFLUENCE OF A
COMBINATION OF THE WESTERN U.S. RIDGE SUPPLYING THE DRY WEATHER AND
THE COOLING INFLUENCE OF NORTHWEST FLOW ON THE BACK SIDE OF THE
EASTERN U.S TROUGH. HIGHS WILL BE SLIGHTLY BELOW NORMAL WITH
COMFORTABLE HUMIDITY AND DECENT SUNSHINE. MOISTURE RETURN IS LACKING
UNTIL LATER IN THE WEEK WHEN A FRONTAL BOUNDARY DROPS THROUGH
THURSDAY NIGHT INTO FRIDAY. THIS WILL BE OUR NEXT CHANCE FOR SHOWERS
AND THUNDERSTORMS.
KMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* MVFR CONDITIONS IN FOG AND LIGHT RAIN SHOWERS...IMPROVING AFTER
20Z.
* WINDS EAST AT 7-9KT THIS AFTERNOON.
* FOG AND LOW CEILINGS TONIGHT...LOW END MVFR CEILINGS WITH IFR
POSSIBLE.
MM
//DISCUSSION...UPDATED 12Z...
LATEST RADAR IMAGERY DEPICTING PRECIP SHIELD STILL SLOWLY MOVING
EAST ACROSS NORTHERN ILLINOIS...WITH ITS EASTERN EXTENT STILL
ERODING AT THIS TIME. MOST GUIDANCE INCLUDING SHORT TERM...NOT
QUITE HANDLING EVOLUTION OF THIS PRECIP TOO WELL THIS
MORNING...BUT STILL THINKING PRECIP WILL REACH THE TERMINALS LATER
TODAY. PERSISTENT FORCING WILL CONTINUE THROUGH MIDDAY AND WHILE
THE COLUMN SATURATES...SHOULD BEGIN TO SEE PRECIP REACHING THE
TERMINALS BY LATE MORNING/MIDDAY. HOWEVER...COVERAGE MAY BE MORE
SCATTERED DURING THIS TIME. CONFIDENCE IS HIGHER THAT ANY THUNDER
TODAY WILL BE WELL SOUTH OF THE TERMINALS...AND HAVE CONTINUED TO
EXCLUDE FROM TAFS. WITH THIS SLOW MOVING SYSTEM ITS POSSIBLE AT
LEAST ISOLATED TO WIDELY SCATTERED SHOWERS MAY LINGER ACROSS THE
TERMINALS THROUGH THIS EVENING...BEFORE DEPARTING TO THE EAST. VFR
CONDITIONS TODAY WILL EVENTUALLY LOWER AND SLOWED THIS TREND THAN
WHAT GUIDANCE IS INDICATING...THINKING THE LOWER CEILINGS WONT
ARRIVE UNTIL LATER THIS EVENING WHEN SURFACE LOW/TROUGH MOVES
OVERHEAD. HAVE LOW END MVFR CEILINGS BUT DO THINK IFR WILL
EVENTUALLY BE POSSIBLE. DONT HAVE A GOOD FEEL WITH TIMING OF THIS
POSSIBLE IFR...AND SO HAVE LEFT OUT AT THIS TIME.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH WITH FOG AND RAIN VSBY RESTRICTIONS.
* HIGH WITH EASTERLY WIND DIRECTION...MEDIUM THAT SPEEDS STAY
BELOW 10KT.
* MEDIUM CONFIDENCE WITH SHOWERS THIS AFTERNOON/EVENING.
* HIGH CONFIDENCE WITH FOG AND LOW CEILINGS OCCURRING
TONIGHT...MEDIUM LOW WITH CIG HEIGHT AND TIMING/DURATION.
MM
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...SLIGHT CHANCE OF THUNDERSTORMS EARLY.
TUESDAY...VFR.
WEDNESDAY...VFR.
THURSDAY...VFR.
FRIDAY...CHANCE OF THUNDERSTORMS.
SATURDAY...VFR.
RODRIGUEZ
&&
.MARINE...
230 AM CDT
HIGHLY VARIABLE WIND FIELD ACROSS THE LAKE THIS MORNING AS A
WEAKER SURFACE PATTERN IN PLACE...WITH HIGH PRESSURE SITUATED TO
THE EAST AND NORTHEAST. THESE VARIABLE WINDS WILL LIKELY PERSIST
ACROSS THE NORTHERN HALF OF THE LAKE TODAY WHILE THE SOUTHERN END
BECOMES MORE SOUTHERLY THIS MORNING...AS LOW PRESSURE SLOWLY MOVES
EAST TOWARDS THE REGION. AS THIS THIS LOW CONTINUES EAST NORTHEAST
TO THE SOUTHERN END OF THE LAKE AND A SEPARATE LOW OVER ONTARIO
MOVES EAST TO HUDSON BAY TONIGHT...WINDS WILL LIKELY CONTINUE TO
BE VARIABLE ACROSS THE LAKE. HOWEVER...IT DOES APPEAR THAT SPEEDS
WILL STAY ON THE LIGHTER SIDE THROUGH THIS PERIOD. THIS LOW WILL
THEN MOVE TO THE EASTERN LAKES MONDAY INTO MONDAY NIGHT AS HIGH
PRESSURE TO THE NORTHWEST BEGINS SPREADING SOUTHEAST...WITH
NORTHERLY WINDS SETTING UP ACROSS THE ENTIRE LAKE. AS THE SURFACE
GRADIENT TIGHTENS UP OVER THE LAKE LATE MONDAY AND MONDAY
NIGHT...NORTHERLY SPEEDS WILL BEGIN TO INCREASE. THIS INCREASING
TREND WITH THE NORTHERLY WINDS CONTINUES TUESDAY WITH 15 TO 25 KT
WINDS BECOMING LIKELY DURING THIS TIME.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS GOODLAND KS
244 PM MDT SUN AUG 9 2015
.SHORT TERM...(THIS AFTERNOON THROUGH MONDAY)
ISSUED AT 132 PM MDT SUN AUG 9 2015
EARLY AFTERNOON WV IMAGERY AND RAP H5 ANALYSIS SHOW RIDGE CONTINUING
TO DOMINATE PATTERN ACROSS SOUTHERN P.LAINS WITH WESTERLY FLOW
ACROSS THE NORTHERN PLAINS. H7 SHORTWAVE TROUGH HAS WEAKENED AND
SHIFTED EAST...WITH ANOTHER H7 SHORTWAVE TROUGH OVER NORTHCENTRAL
COLORADO. AT THE SURFACE HIGH PRESSURE IS IN PLACE OVER OUR
CWA...WITH A STATIONARY FRONT EXTENDING FROM NORTHEAST COLORADO
ACROSS NORTHCENTRAL NEBRASKA.
THIS AFTERNOON-TONIGHT...AS FIRST H7 TROUGH HAS WEAKENED AND SHIFTED
EAST SUBSIDENCE HAS SPREAD INTO THE WESTERN PART OF THE FORECAST
AREA WITH LOWER TD VALUES (UPPER 40S/LOWER 50S) ADVECTING INTO THE
WESTERN PARTS OF THE FORECAST AREA. RESULT HAS BEEN CAPE VALUES
DROPPING OFF SHARPLY AND SABLE AIR MOVING BACK OVER THE CWA. SHORT
RANGE GUIDANCE CONTINUES TO KEEP HIGHER TD/CAPE VALUES IN OUR
EASTERN CWA WITH ONLY 100-500 J/KG IN THE WEST THROUGH THE EVENING.
CAPE VALUES AROUND 2000 J/KG ACROSS OUR EASTERN CWA COULD SUPPORT A
FEW MARGINALLY SEVERE THUNDERSTORMS IF SOMETHING WAS TO DEVELOP
ALONG WHAT IS LIKELY A DEVELOPING DRY LINE. NOT A LOT OF CONFIDENCE
AND HI RES GUIDANCE HAS TRENDED AWAY FROM ADDITIONAL DEVELOPMENT IN
OUR EAST. IT APPEARS THAT CHANCES ARE DECREASING FOR MOST OF THE CWA
THIS AFTERNOON. THERE IS THE POSSIBILITY FOR A SHOWER OR
THUNDERSTORM IN THE WESTERN CWA AS ANOTHER SHORTWAVE MOVES IN FROM
THE WEST LATE THIS AFTERNOON THROUGH THIS EVENING...WITH BEST
PRECIP SIGNAL IN THE SW. NOT A LOT OF CONFIDENCE AT THIS POINT IN
COVERAGE...SO I DECIDED TO LIMIT POPS TO THE WEST THIS EVENING
WITH A DOWNWARD TREND THROUGH 06Z.
IT DOES APPEAR THAT HIGHER TD VALUES WILL BEGIN TO RECOVER OVERNIGHT
FROM THE EAST/NORTHEAST WITH SURFACE HIGH PRESSURE/LOW LEVEL
STABILITY SUPPORTING POSSIBLE FOG/STRATUS DEVELOPMENT. BASED ON
SHORT RANGE GUIDANCE AND PERSISTENCE I KEPT HIGHER FOG COVERAGE
(AREAS) LIMITED TO REPUBLICAN RIVER VALLEY IN SW NEBRASKA.
MONDAY...GUIDANCE CONTINUES TO SHOW PRECIP SIGNAL LINGERING ACROSS
THE SW PART OF OUR CWA. ANY SHORTWAVE TROUGHS/VORT MAXES ROTATING
THROUGH PERIPHERY OF THE RIDGE APPEAR TO REMAIN SW OF OUR CWA WITH
VERY LIMITED FORCING. INSTABILITY DOES BEGIN TO INCREASE SO IF
ACTIVITY WAS TO DEVELOP TO THE WEST WE COULD SEE DEVELOPMENT TOWARDS
THE SW PART OF OUR FORECAST AREA. I WASNT CONFIDENT ENOUGH TO
INCREASE POPS DESPITE OVERLAPPING QPF FIELDS IN GUIDANCE...SO I
LIMITED POPS TO 20/30 RANGE MONDAY AFTERNOON. HIGH TEMPS AS WITH THE
LAST FEW DAYS WILL BE HIGHLY DEPENDENT ON MORNING STRATUS CLEARING
WHICH IS CURRENTLY EXPECTED. RESULT SHOULD BE SEASONAL HIGHS IN THE
UPPER 80S/AROUND 90.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 244 PM MDT SUN AUG 9 2015
FORECAST PROBLEM WILL BE CONTINUED THUNDERSTORM CHANCES. SATELLITE
IS SHOWING AN AMPLIFIED AND MOSTLY PROGRESSIVE FLOW FROM THE PACIFIC
INTO NORTH AMERICA. SOUTHERN UNITED STATES RIDGE REMAINS CENTERED
OVER CENTRAL/EASTERN TEXAS.
MODELS STARTED OUT FINE AT JET LEVEL. AT MID LEVELS...THE
GFS/CANADIAN WERE INITIALLY DOING BETTER THAN THE REST OF THE OUT
WITH THE NAM/SREF THE WORST OF THE REST OF THE BUNCH. THE SREF
LOOKED LIKE IT WAS THE BEST AT THE SURFACE. IT LOOKED LIKE THE
GFS...CANADIAN AND ECMWF WERE DOING THE BEST ON THE LOW LEVEL
THERMAL FIELD AT THIS TIME.
MONDAY NIGHT...LOW LEVEL UPSLOPE WINDS WILL BE IN PLACE THROUGH THE
NIGHT AS SURFACE RIDGE NOSES DOWN INTO THE AREA. AS SHOWN THE LAST
TWO DAYS...THE SHORTWAVE RIDGE AT 700 MB WILL SLOWLY MOVE TOWARD THE
EAST THROUGH THE NIGHT AS A SHORTWAVE MOVES IN FROM THE WEST. MODELS
HAVE SLOWED THINGS UP A LITTLE...AS HAS THE TREND BEEN THE LAST FEW
DAYS AS WELL. THE GFS IS THE FURTHEST EAST WHICH IS NOT AN UCOMMON
THING WHEN IT COMES TO BREAKING DOWN RIDGES TOO FAST.
SO ONLY PROGRESSED THE POPS SLOWLY TO THE EAST THROUGH THE NIGHT.
THE COMBINATION OF SLOW STORM MOVEMENT...PWS OF 1 TO 1.5 INCHES AND
THE COMMON HEAVY RAIN SCENARIO OF A SHORTWAVE MOVING UP THE WEST
SIDE OF A RIDGE COULD PRODUCE SOME LOCALIZED HEAVY RAINFALL. RAMPED
THE AMOUNTS UP A LITTLE AND INCREASED THE INTENSITY OF THE RAINFALL
AS WELL. THE BEST CHANCE FOR RAINFALL WILL BE IN THE SOUTHWEST THIRD
TO HALF OF THE AREA. THIS PERIOD WILL NEED TO BE WASHED CLOSELY.
TUESDAY/TUESDAY NIGHT...SLOWLY EVOLVING SITUATION THAT BEGINS MONDAY
NIGHT...SLOWLY MOVING CONVECTIVELY INDUCED SYSTEM...CONTINUE THROUGH
THIS ENTIRE PERIOD. MODELS ARE IN GOOD AGREEMENT ABOUT THIS. MORE
THAN LIKELY SOME DEGREE OF CONVECTION WILL CONTINUE FROM THIS
PREVIOUS THROUGH THIS ENTIRE PERIOD. AGAIN SAME HEAVY RAIN SCENARIO
IS IN PLACE AS IN THE PREVIOUS PERIOD AND WILL HAVE TO BE WATCHED
CLOSELY. ALSO THE SOUTHWEST THIRD TO HALF WILL HAVE THE BEST CHANCE
OF RAINFALL...ESPECIALLY DURING THE DAY. THE AREA OF RAINFALL WILL
SLOWLY MOVE TO THE SOUTH AND EAST DURING THE NIGHT.
COMBINATION OF UPSLOPE SURFACE WINDS...LOTS OF CLOUD COVER AND
ONGOING PRECIPITATION...WILL KEEP TEMPERATURES FROM WARMING UP TOO
MUCH...ESPECIALLY IN THE SOUTHWEST HALF. SO LOWERED TEMPERATURES
AROUND 5 DEGREES OR SO. THE COOLEST OUTPUT HAS TEMPERATURES COOLER
THAN WHAT I HAVE THEM.
WEDNESDAY...SLOW MOVING UPPER SYSTEM WILL KEEP RAINFALL AROUND
THROUGH THE MORNING HOURS IN THE SOUTHEAST HALF. IF THERE IS ANY
MORE SLOWLY...THE POPS WILL NEED TO BE RAISED. TEMPERATURES WILL BE
A LITTLE WARMER BUT HOW MUCH WILL DEPEND ON HOW FAST THE SYSTEM AND
ASSOCIATED CLOUDS/RAINFALL MOVE OUT OF THE AREA. AGAIN IF ANY MORE
SLOWING TEMPERATURES WILL NEED TO BE LOWERED.
WEDNESDAY NIGHT THROUGH SUNDAY...NOT TOO MUCH HAS CHANGED FROM WHAT
THE MODELS HAVE BEEN DOING/SHOWING FROM THE LAST FEW DAYS. MODELS
STILL DIFFER ON THE AMPLITUDED AND POSITION OF WHAT IS NOW THE
SOUTHERN RIDGE THAT TRANSITIONS TO A MORE CENTERED WESTERN RIDGE. IN
GENERAL UPPER RIDGE STAYS CENTERED NEAR THE FOUR CORNERS REGION.
SINCE MUCH DOES CHANGE ALOFT...THE SURFACE ALSO DOES NOT CHANGE TOO
MUCH. A SURFACE TROUGH OR LINGERING FRONTAL BOUNDARY STAYS NEAR OR
OVER THE WESTERN PORTION OF THE AREA.
FORECAST WILL HINGE ON SMALL IMPORTANT DETAILS THAT WILL BE HARD TO
PIN DOWN AT THIS TIME SCALE. POSITION OF THE RIDGE SHOULD ALLOW
SUBTROPICAL MOISTURE/WEAK SHORTWAVE TROUGHS TO ROTATE AROUND THE
RIDGE INTO THE AREA. ALSO THE SURFACE BOUNDARY SHOULD HELP SET
THUNDERSTORMS OFF. THERE WILL NOT BE HIGH PRECIPITATION CHANCES BUT
HARD TO SAY THERE WILL NOT BE ANYTHING AT ALL. PER THE OVERNIGHT
DISCUSSION/REASONING...THE WESTERN PORTION OF THE AREA WILL PROBABLY
SEE THE BEST CHANCE DUE TO THE PROXIMITY OF THE SURFACE BOUNDARY.
THE NEW CRH_INIT IS IN GOOD AGREEMENT WITH THE ABOVE MENTIONED
SCENARIO/REASONING...SO ONCE AGAIN MADE NO CHANGES TO IT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1124 AM MDT SUN AUG 9 2015
ISOLATED TO SCATTERED SHOWER ACTIVITY IS CURRENTLY MOVING WITHIN
THE VICINITY OF BOTH KGLD AND KMCK TERMINALS. UPPER LEVEL SYSTEM
RESPONSIBLE FOR THIS ACTIVITY WILL CONTINUE TO SHIFT EAST THROUGH
THIS AFTERNOON AS INSTABILITY INCREASES...SO A FEW THUNDERSTORMS
COULD DEVELOP THIS AFTERNOON/EVENING. AT THIS TIME IT APPEARS MOST
THUNDERSTORM ACTIVITY SHOULD BE EAST/SOUTHEAST AND COVERAGE AND
POTENTIAL IMPACT AT EITHER TERMINAL IS IN QUESTION. DECIDED TO
KEEP VCSH MENTION AND HOLD OFF ON THUNDERSTORM MENTION DURING THIS
UPDATE.
SURFACE HIGH PRESSURE WILL CONTINUE TO SPREAD SOUTH WITH
LIGHT WINDS AT BOTH TERMINALS THROUGH THE TAF PERIOD. FOG/STRATUS
IS EXPECTED TO REDEVELOP 10-12Z AT KMCK AND LAST THROUGH MID
MORNING MONDAY. WITH AMPLE MOISTURE IN PLACE AND VERY STABLE LOW
LEVELS FOG/STRATUS COULD SPREAD AS FAR WEST AS KGLD. CONFIDENCE IS
HIGHER AT KMCK WHERE IFR CONDITIONS APPEAR LIKELY AND BRIEF LIFR
CONDITIONS WILL BE POSSIBLE.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...BULLER
AVIATION...DR
AREA FORECAST DISCUSSION
NWS TOPEKA KS
313 PM CDT SUN AUG 9 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 313 PM CDT SUN AUG 9 2015
CURRENT SURFACE ANALYSIS SHOWS THE MAIN SYNOPTIC BOUNDARY EXTENDING
SOUTHWARD FROM KANSAS CITY TO WICHITA, WHICH IS FORECAST TO SAG
SOUTHWARD THROUGH THE AFTERNOON AND EVENING HOURS. ALTHOUGH THE MORE
EVIDENT THERMAL GRADIENT HAS PUSHED INTO SOUTHEAST KS AND HAS BEEN
RESPONSIBLE FOR SCATTERED SHOWERS AND ISOLATED THUNDER THIS MORNING.
THIS HAS KEPT THE CLOUD COVER AROUND MUCH LONGER THAN FORECASTED,
BUT AN AREA OF CLEAR SKIES IS WORKING EASTWARD ACROSS NORTHEAST KS,
WHICH MAY ALLOW TEMPERATURES TO WARM INTO THE LOWER TO MIDDLE 90S.
HIGH MOISTURE POOLING IN THE BOUNDARY LAYER HAS KEPT DEW POINTS IN
THE MID TO UPPER 70S. EXPECT THAT HEAT INDICES WILL BE IN THE LOWER
100S THROUGH EARLY EVENING FOR LOCATIONS ALONG AND SOUTH OF I-70.
THERE WILL BE A FEW THINGS OF CONCERN LATER THIS EVENING AND
OVERNIGHT. THE MODELS SHOW A SHORTWAVE TROUGH ON THE NORTHERN
PERIPHERY OF THE UPPER HIGH CENTERED OVER THE SOUTHERN PLAINS WILL
TRACK ACROSS SOUTHERN KS TONIGHT. THIS MAY SUPPORT THE DEVELOPMENT
OF AN MCS OR MULTICELL CLUSTER IN WESTERN OR CENTRAL KS THIS EVENING
NORTH OF THE SURFACE BOUNDARY. SURFACE BASED CONVECTION HAS ALREADY
BEGAN IN NORTHWEST KS. AS THAT BOUNDARY DRIFTS SOUTHWARD THE TRACK
OF THE MCS MAY ALSO DO THE SAME AS DEPICTED BY THE NAM. THE PAST FEW
RUNS OF THE HRRR HAVE BEEN CLIPPING THE SOUTHERN FORECAST AREA WITH
THIS MCS. INSTABILITY HAS BEEN SOMEWHAT LIMITED TODAY ACROSS
SOUTHERN KS AS OPPOSED TO NORTHERN KS, WHICH HAS SET UP A DECENT
GRADIENT. THEREFORE IT IS UNCERTAIN HOW SEVERE THESE STORMS WILL BE
THIS EVENING, BUT THE TRACK MAY BE MORE FOCUSED ALONG THIS
INSTABILITY GRADIENT INSTEAD. AS FOR NOW THE BEST CHANCES FOR PRECIP
WILL BE SOUTH OF I-70 LATE THIS EVENING AND EARLY MORNING WITH THE
SLIGHT CHANCE FOR A STRONG STORM. WITH PLENTY OF MOISTURE AROUND AND
LIGHT LOW LEVEL WINDS ASSOCIATED WITH THE BOUNDARY THERE IS A CHANCE
FOR HAZE AND OR FOG EARLY TOMORROW MORNING. THERE ARE SOME
INDICATIONS THAT THE SKIES COULD CLEAR LATE TONIGHT AND ALLOW FOR
BOUNDARY LAYER COOLING. A FEW OF THE MODELS ARE HINTING AT A
NORTHERN SHORTWAVE THAT WILL TRACK OVER SD AND NE OVERNIGHT. THIS
MAY ALSO SUPPORT A SOUTHEASTWARD MOVING MCS THAT COULD REACH
NORTHERN KS AROUND SUNRISE. IN FACT, THE INSTABILITY IS ALREADY
DECENT IN THAT AREA, WHICH WOULD SUPPORT THIS SCENARIO BETTER.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 313 PM CDT SUN AUG 9 2015
THERE IS NOT MUCH CHANGE IN THE FORECAST FOR MONDAY NIGHT THROUGH
SUNDAY AS MODELS CONTINUE TO SHOW AN UPPER LEVEL RIDGE AMPLIFYING
TO THE WEST AND SOUTHWEST CAUSING NORTHWEST FLOW TO SET UP OVER
THE FORECAST AREA. ABOUT THE ONLY THING OF CONCERN IS THE
POSSIBILITY FOR SOME ELEVATED PRECIP ACROSS NORTH CENTRAL KS LATE
TUESDAY NIGHT AND WEDNESDAY MORNING. THERE ARE INDICATIONS THAT
CONVECTION IN THE MOUNTAINS COULD GENERATE A VORT MAX AND THEN
DRIFT EAST AND SOUTH THROUGH CENTRAL KS. FOR NOW MOST GUIDANCE
KEEPS ANY PRECIP JUST TO THE WEST OF THE FORECAST AREA. THIS SEEMS
TO MAKE SINCE AS MODELS BRING THE CENTER OF THE 850 MB RIDGE OVER
THE FORECAST AREA BY 12Z WED WITH NO REAL RETURN FLOW AND THE
DEEPER MOISTURE AXIS REMAINING OVER WESTERN KS. SO THE FORECAST
REMAINS DRY THROUGH NEXT WEEKEND WITH NO OBVIOUS SIGNS OF FORCING
IMPACTING THE FORECAST AREA AFTER WEDNESDAY.
TEMPS ARE EXPECTED TO BE COOLER THAN NORMAL FOR TUESDAY THROUGH
THURSDAY. MODELS ARE IN AGREEMENT THAT A MODIFIED HIGH PRESSURE
SYSTEM WILL BUILD INTO THE AREA WITH SOME WEAK COLD AIR ADVECTION
AND DRYER AIR. BECAUSE OF THIS LOWS SHOULD BE IN THE LOWER AND MID
60S WITH HIGHS IN THE 80S. BY FRIDAY AND INTO THE WEEKEND, THE
UPPER RIDGE IS EXPECTED TO PROPAGATE EAST INTO THE PLAINS AS AN
UPPER TROUGH OVER THE PACIFIC NORTHWEST COAST MOVES INLAND. THIS
SHOULD SHIFT THE THERMAL RIDGE OUT INTO THE PLAINS WITH HIGHS
WARMING BACK INTO THE LOWER AND MID 90S FOR THE WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1225 PM CDT SUN AUG 9 2015
THERE IS A CHANCE FOR SHOWERS AND STORMS LATE THIS AFTERNOON AND
EARLY EVENING. HEAVY RAIN COULD REDUCE VISIBILITIES FOR A BRIEF
PERIOD OTHERWISE VFR. WITH LIGHT WIND AND CLEARING SKIES FOG/HAZE
WILL BE POSSIBLE TOMORROW MORNING AROUND SUNRISE. NOT SURE HOW LOW
THE VISIBILITIES WILL GO BUT WENT WITH MVFR FOR NOW. THERE IS A
CHANCE THAT MOISTURE MIXES INTO A MVFR CLOUD DECK AT THE END OF
THE TAF PERIOD.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...SANDERS
LONG TERM...WOLTERS
AVIATION...SANDERS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
132 PM MDT SUN AUG 9 2015
.SHORT TERM...(THIS AFTERNOON THROUGH MONDAY)
ISSUED AT 132 PM MDT SUN AUG 9 2015
EARLY AFTERNOON WV IMAGERY AND RAP H5 ANALYSIS SHOW RIDGE CONTINUING
TO DOMINATE PATTERN ACROSS SOUTHERN P.LAINS WITH WESTERLY FLOW
ACROSS THE NORTHERN PLAINS. H7 SHORTWAVE TROUGH HAS WEAKENED AND
SHIFTED EAST...WITH ANOTHER H7 SHORTWAVE TROUGH OVER NORTHCENTRAL
COLORADO. AT THE SURFACE HIGH PRESSURE IS IN PLACE OVER OUR
CWA...WITH A STATIONARY FRONT EXTENDING FROM NORTHEAST COLORADO
ACROSS NORTHCENTRAL NEBRASKA.
THIS AFTERNOON-TONIGHT...AS FIRST H7 TROUGH HAS WEAKENED AND SHIFTED
EAST SUBSIDENCE HAS SPREAD INTO THE WESTERN PART OF THE FORECAST
AREA WITH LOWER TD VALUES (UPPER 40S/LOWER 50S) ADVECTING INTO THE
WESTERN PARTS OF THE FORECAST AREA. RESULT HAS BEEN CAPE VALUES
DROPPING OFF SHARPLY AND SABLE AIR MOVING BACK OVER THE CWA. SHORT
RANGE GUIDANCE CONTINUES TO KEEP HIGHER TD/CAPE VALUES IN OUR
EASTERN CWA WITH ONLY 100-500 J/KG IN THE WEST THROUGH THE EVENING.
CAPE VALUES AROUND 2000 J/KG ACROSS OUR EASTERN CWA COULD SUPPORT A
FEW MARGINALLY SEVERE THUNDERSTORMS IF SOMETHING WAS TO DEVELOP
ALONG WHAT IS LIKELY A DEVELOPING DRY LINE. NOT A LOT OF CONFIDENCE
AND HI RES GUIDANCE HAS TRENDED AWAY FROM ADDITIONAL DEVELOPMENT IN
OUR EAST. IT APPEARS THAT CHANCES ARE DECREASING FOR MOST OF THE CWA
THIS AFTERNOON. THERE IS THE POSSIBILITY FOR A SHOWER OR
THUNDERSTORM IN THE WESTERN CWA AS ANOTHER SHORTWAVE MOVES IN FROM
THE WEST LATE THIS AFTERNOON THROUGH THIS EVENING...WITH BEST
PRECIP SIGNAL IN THE SW. NOT A LOT OF CONFIDENCE AT THIS POINT IN
COVERAGE...SO I DECIDED TO LIMIT POPS TO THE WEST THIS EVENING
WITH A DOWNWARD TREND THROUGH 06Z.
IT DOES APPEAR THAT HIGHER TD VALUES WILL BEGIN TO RECOVER OVERNIGHT
FROM THE EAST/NORTHEAST WITH SURFACE HIGH PRESSURE/LOW LEVEL
STABILITY SUPPORTING POSSIBLE FOG/STRATUS DEVELOPMENT. BASED ON
SHORT RANGE GUIDANCE AND PERSISTENCE I KEPT HIGHER FOG COVERAGE
(AREAS) LIMITED TO REPUBLICAN RIVER VALLEY IN SW NEBRASKA.
MONDAY...GUIDANCE CONTINUES TO SHOW PRECIP SIGNAL LINGERING ACROSS
THE SW PART OF OUR CWA. ANY SHORTWAVE TROUGHS/VORT MAXES ROTATING
THROUGH PERIPHERY OF THE RIDGE APPEAR TO REMAIN SW OF OUR CWA WITH
VERY LIMITED FORCING. INSTABILITY DOES BEGIN TO INCREASE SO IF
ACTIVITY WAS TO DEVELOP TO THE WEST WE COULD SEE DEVELOPMENT TOWARDS
THE SW PART OF OUR FORECAST AREA. I WASNT CONFIDENT ENOUGH TO
INCREASE POPS DESPITE OVERLAPPING QPF FIELDS IN GUIDANCE...SO I
LIMITED POPS TO 20/30 RANGE MONDAY AFTERNOON. HIGH TEMPS AS WITH THE
LAST FEW DAYS WILL BE HIGHLY DEPENDENT ON MORNING STRATUS CLEARING
WHICH IS CURRENTLY EXPECTED. RESULT SHOULD BE SEASONAL HIGHS IN THE
UPPER 80S/AROUND 90.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 248 AM MDT SUN AUG 9 2015
AN UPPER LEVEL RIDGE WILL CONTINUE TO BE IN PLACE OVER THE TRI STATE
AREA TO START OFF THE LONG TERM PERIOD WEDNESDAY. THE CENTRAL AREA
OF HIGH PRESSURE WILL REMAIN OVER THE ROCKY MOUNTAIN RANGE AND THE
CENTRAL PLAINS WEDNESDAY. WITH THE PRESENCE OF THE UPPER
RIDGE...JET AREAS AND POCKETS OF VORTICITY WILL REMAIN WELL AWAY
FROM THE TRI STATE AREA...WHICH WILL BRING UPPER STABILITY FOR THE
REST OF THE FORECAST PERIOD.
AT THE SURFACE...MAINLY SOUTHERLY FLOW WILL ADVECT WARM MOIST AIR
INTO THE HIGH PLAINS WITH A BIT OF AN UPSLOPE COMPONENT AS WINDS ARE
SOMEWHAT SOUTHEASTERLY. GFS/ECMWF MODEL SOUNDINGS SHOW PRECIPITABLE
WATER VALUES BETWEEN 1 AND 1.5 INCHES OVER THE TRI STATE AREA WITH
SOME CAPE IN THE PROFILE THAT WOULD BE CONDUCIVE TO STEADY RAINFALL
PRODUCTION. WITH CAP VIA MODEL SOUNDINGS APPEARING CLOSE TO BEING
ABLE TO BREAK DUE TO SURFACE HEATING DESPITE A LACK OF STRONG
SURFACE AND UPPER LEVEL FORCING...CHANCES FOR SHOWERS AND
THUNDERSTORMS ARE POSSIBLE WEDNESDAY EVENING MAINLY FOR SOUTH OF
INTERSTATE 70 ALONG THE SURFACE TROUGH AND A WEAK DRY LINE
FEATURE.
CHANCES FOR AFTERNOON SHOWERS AND THUNDERSTORMS ARE ALSO POSSIBLE
HEADING INTO THURSDAY...FRIDAY AND SATURDAY WITH A WEAK QUASI
STATIONARY SURFACE DEFORMATION ZONE INDICATED BY THE GFS/ECMWF
SURFACE FORECASTS. CURRENTLY THINKING THE BEST CHANCE FOR STORMS
WILL BE IN EASTERN COLORADO ALONG A SURFACE CONFLUENT LINE THAT
REMAINS IN PLACE DURING THE LATER PART OF THE FORECAST PERIOD.
HIGH TEMPERATURES THROUGH THE PERIOD ARE EXPECTED TO BE ABOUT NORMAL
IN THE UPPER 80S TO LOWER 90S...AND LOW TEMPERATURES IN THE LOW TO
MID 60S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1124 AM MDT SUN AUG 9 2015
ISOLATED TO SCATTERED SHOWER ACTIVITY IS CURRENTLY MOVING WITHIN
THE VICINITY OF BOTH KGLD AND KMCK TERMINALS. UPPER LEVEL SYSTEM
RESPONSIBLE FOR THIS ACTIVITY WILL CONTINUE TO SHIFT EAST THROUGH
THIS AFTERNOON AS INSTABILITY INCREASES...SO A FEW THUNDERSTORMS
COULD DEVELOP THIS AFTERNOON/EVENING. AT THIS TIME IT APPEARS MOST
THUNDERSTORM ACTIVITY SHOULD BE EAST/SOUTHEAST AND COVERAGE AND
POTENTIAL IMPACT AT EITHER TERMINAL IS IN QUESTION. DECIDED TO
KEEP VCSH MENTION AND HOLD OFF ON THUNDERSTORM MENTION DURING THIS
UPDATE.
SURFACE HIGH PRESSURE WILL CONTINUE TO SPREAD SOUTH WITH
LIGHT WINDS AT BOTH TERMINALS THROUGH THE TAF PERIOD. FOG/STRATUS
IS EXPECTED TO REDEVELOP 10-12Z AT KMCK AND LAST THROUGH MID
MORNING MONDAY. WITH AMPLE MOISTURE IN PLACE AND VERY STABLE LOW
LEVELS FOG/STRATUS COULD SPREAD AS FAR WEST AS KGLD. CONFIDENCE IS
HIGHER AT KMCK WHERE IFR CONDITIONS APPEAR LIKELY AND BRIEF LIFR
CONDITIONS WILL BE POSSIBLE.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...MK
AVIATION...DR
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
345 PM EDT SUN AUG 9 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 345 PM EDT SUN AUG 9 2015
18Z SFC ANALYSIS SHOWS HIGH PRESSURE STILL IN CONTROL OF THE
WEATHER ACROSS EAST KENTUCKY. HIGH CLOUDS ARE MOVING IN FROM THE
NORTHWEST AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM WHILE
SCATTERED CU IS DISSIPATING OVER THE AREA. TEMPERATURES ARE
TOPPING OUT IN THE MIDDLE TO UPPER 80S THROUGH EAST KENTUCKY WHILE
DEWPOINTS VARY FROM THE MID 60S NORTH TO THE LOWER 70S IN THE
SOUTH WITH LIGHT AND VARIABLE WINDS.
THE MODELS ARE IN GOOD AGREEMENT WITH THE PATTERN ALOFT OVER THE
REGION. THEY ALL DEPICT KENTUCKY ON THE NORTHEAST FRINGE OF A
STRONG RIDGE CENTERED OVER CENTRAL TEXAS. THIS PLACES THE AREA IN
NORTHWEST FLOW WITH A COUPLE OF MINOR SHORTWAVES GLIDING PAST THE
CWA INTO MONDAY MORNING. THE PATTERN WILL FURTHER AMPLIFY THROUGH
THE OHIO VALLEY AND APPALACHIANS AS A TROUGH FROM CENTRAL CANADA
WILL DIVE INTO THE GREAT LAKES LATER MONDAY...SWEEPING INTO THE
OHIO VALLEY BY 12Z TUESDAY. SIGNIFICANT HEIGHT FALLS WILL SPREAD
OVER EASTERN KENTUCKY AS A RESPONSE ALONG WITH ADDITIONAL ENERGY
CLUSTERS. GIVEN THE MODEL AGREEMENT HAVE FOLLOWED THE HIGHER
RESOLUTION HRRR AND NAM12 MOST CLOSELY INITIALLY FOLLOWING WITH
WITH IDEAS FROM THE GFS AND ECMWF LATER ON IN THE SHORT TERM.
SENSIBLE WEATHER WILL FEATURE A QUIET EVENING UNDER HIGH
CLOUDS...THIN ENOUGH TO YIELD A SMALL RIDGE TO VALLEY TEMPERATURE
SPLIT. THE CLOUDS WILL THICKEN UP DURING THE EARLY MORNING HOURS
WITH A SEMI-ORGANIZED AREA OF SHOWERS AND THUNDERSTORMS
POTENTIALLY MOVING INTO THE AREA DURING THE PRE-DAWN HOURS FROM
NORTHWEST TO SOUTHEAST. THIS MAY STABILIZE THE ENVIRONMENT FOR A
TIME BEFORE INSTABILITY BUILDS ENOUGH FOR ANOTHER ROUND OF
ACTIVITY LATER IN THE DAY MONDAY. FROM EITHER OF THESE ROUNDS OF
CONVECTION A STORM OR TWO COULD GET STRONG ENOUGH TO MAKE DAMAGING
WIND GUSTS A POTENTIAL THREAT - WILL ADDRESS THIS IN THE
FORTHCOMING HWO. THIS SYSTEM/S COLD FRONT WILL PASS THROUGH LATER
MONDAY NIGHT WITH A LINGER SHOT AT SHOWERS OR STORMS AS IT EXITS
EARLY TUESDAY MORNING. DUE TO THE CLOUD COVER TONIGHT AND MONDAY
NIGHT HAVE KEPT FOG TO A MINIMUM IN THE GRIDS...BUT IT COULD BE
MORE SUBSTANTIAL TUESDAY MORNING SHOULD THE CLOUDS AND PCPN MANAGE
TO CLEAR OUT EARLIER MONDAY NIGHT.
AGAIN USED THE SHORTBLEND GUIDANCE AS A STARTING POINT THROUGH
THE FIRST PART OF THE FORECAST FOR THE T/TD/WIND GRIDS WITH A
SWITCH TO THE SUPERBLEND FOR THE REMAINDER. DID MAKE SOME
MINOR CHANGES TO LOWS TONIGHT BASED ON THE TERRAIN WITH A SMALL
RIDGE TO VALLEY SPLIT EXPECTED INTO THE EARLY MORNING HOURS. AS
FOR POPS...ENDED UP CLOSEST TO THE MET NUMBERS THROUGH THE
PERIOD.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 313 PM EDT SUN AUG 9 2015
THE MAJORITY OF THE EXTENDED LOOKS TO BE DRY AND PLEASANT WITH
SHOWERS AND STORMS AFFECTING EASTERN KENTUCKY DURING THE DAY ON
TUESDAY...AND BELOW NORMAL TEMPERATURES TUESDAY THROUGH FRIDAY.
MOIST UPSLOPE FLOW BEHIND A DEPARTING WEATHER SYSTEM WILL ALLOW
PRECIPITATION TO LINGER ACROSS THE AREA THROUGH LATE TUESDAY
AFTERNOON. THE PRECIPITATION WILL BE USHERED OUT OF EASTERN KENTUCKY
AS A STRONG RIDGE OF HIGH PRESSURE BEGINS BUILDING INTO THE AREA
FROM THE WEST. THIS FEATURE WILL BRING DRY CONDITIONS AND COOLER
THAN NORMAL TEMPERATURES TO EAST KENTUCKY FOR THE REST OF THE
WEEK...AS A COOL AND DRY AIR MASS MOVES FROM THE NORTHERN ROCKY
MOUNTAIN REGION AND INTO THE OHIO AND TENNESSEE VALLEY REGIONS.
HIGH TEMPERATURES ON WEDNESDAY AND THURSDAY ARE EXPECTED TO MAX OUT
IN THE UPPER 70S FOR MOST LOCATIONS...WITH LOWER 80S FOR HIGHS ON
TAP FOR TUESDAY AND FRIDAY. OVERNIGHT LOWS MAY FALL AS LOW AS THE
MID TO UPPER 50S WEDNESDAY NIGHT AND THURSDAY NIGHT AS CLEAR SKIES
AND NEAR CALM WINDS REMAIN IN PLACE. MINIMUM READINGS ARE EXPECTED
TO BOTTOM OUT IN THE 60S THE OTHER NIGHTS OF THE UPCOMING WORK
WEEK...WITH LOW TO MID 60S EXPECTED FOR FRIDAY NIGHT AND SATURDAY
NIGHT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 230 PM EDT SUN AUG 9 2015
CONDITIONS WILL BE VFR EVENING STILL A BIT OF UNCERTAINTY IN HOW
MUCH FOG WILL PLAY A ROLE...IF ANY...IN TAFS TONIGHT GIVEN
INCREASING HIGH AND THEN MID LEVEL CLOUDS AHEAD OF THE APPROACHING
COLD FRONT. ACCORDINGLY...HAVE LEANED AWAY FROM ANY SIGNIFICANT
FOG AND INSTEAD FOCUSED ON THE POTENTIAL FOR A SEMI-ORGANIZED
CLUSTER OF SHOWERS AND STORMS TO MOVE THROUGH DURING THE EARLY
MORNING HOURS OF MONDAY. INTRODUCED A TEMPO WITH CIGS AND VIS
INTO THE IFR TO MVFR RANGE WITH THE CONVECTION. ADDITIONAL STORMS
WILL BE POSSIBLE THROUGH THE REST OF THE DAY WITH VCTS PREVAILING
IN THE TAFS AFTER THE FIRST ROUND FADES OUT. ALTHOUGH NEAR STORM
WINDS COULD BE NEAR 25 KTS...THE BULK OF THE TIME THEY WILL BE
LIGHT AND VARIABLE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
123 PM EDT SUN AUG 9 2015
...UPDATED AVIATION DISCUSSION...
...FORECAST UPDATE...
ISSUED AT 855 AM EDT SUN AUG 9 2015
HAVE A NEW NORTH/SOUTH ORIENTED BAND OF STORMS FORMING OVER
SOUTHWEST ILLINOIS THIS HOUR. THE HRRR FROM 08-09Z HAD THIS
BAND...BUT THE LATEST RUN DOES NOT. THE EARLIER RUNS SHOWED THIS
BAND DISSIPATING BEFORE IT GETS INTO OUR REGION...BUT DOES SHOW A
CHANCE IN THE MID TO LATE AFTERNOON HOURS FOR SOME LIGHT RAINS WITH
PERHAPS A RUMBLE OF THUNDER OVER OUR NORTHERN FORECAST HOUR. STILL
LOOKING LIKE A SWATH OF STORMS WILL MOVE ACROSS SOME PARTS OF THE
REGION OVERNIGHT. MADE SOME SLIGHT TWEAKS TO THE EVENING FORECAST
POPS...AS WELL AS BLENDED CURRENT OBS INTO THE ONGOING FORECAST.
.SHORT TERM (NOW THROUGH MONDAY)...
ISSUED AT 330 AM EDT SUN AUG 9 2015
IN THE NEAR TERM, CLEAR TO PARTLY CLOUDY SKIES WERE NOTED ACROSS THE
FORECAST AREA. EARLY MORNING TEMPERATURES WERE IN THE MID-UPPER
60S. SOME PATCHY FOG WAS DEVELOPING ACROSS THE TYPICAL FOG PRONE
AREAS. CLEAR TO PARTLY CLOUDY SKIES WILL CONTINUE FOR THE REMAINDER
OF THE NIGHT WITH LOW TEMPERATURES HITTING THEIR MINIMUMS TOWARD
DAWN.
FOR TODAY, THE OHIO VALLEY WILL SEE ONE MORE DAY UNDER THE INFLUENCE
OF AN UPPER LEVEL RIDGE. WE`RE ON THE NORTHEASTERN PERIPHERY OF THE
RIDGE AXIS AND THIS RIDGE IS FORECAST TO RETROGRADE WESTWARD THROUGH
THE PERIOD. AS THIS OCCURS, WE`LL SEE OUR FLOW PATTERN REVERT BACK
TO A NORTHWESTERLY FLOW. WITHIN THIS NORTHWESTERLY FLOW, A SERIES
OF MID-LEVEL WAVES ROTATING AROUND THE EDGE OF THE RIDGE WILL ROLL
THROUGH THE REGION. CLOUDS WILL BE ON THE INCREASE TODAY WITH HIGH
CIRRUS ROLLING INTO THE REGION. AFTERNOON HIGHS SHOULD BE SLIGHTLY
WARMER THAN WHAT WE SAW SATURDAY AFTERNOON WITH MID-UPPER 80S ACROSS
THE REGION.
FOR TONIGHT, THE FIRST IN A SERIES OF WAVES WILL PUSH INTO THE
REGION LATE. THIS FEATURE SHOULD SPAWN AN MCS TO OUR NORTHWEST
WHICH SHOULD THEN DIVE EAST-SOUTHEAST. BY THE TIME IT REACHES OUR
AREA EARLY MONDAY MORNING, IT IS FORECAST TO BE IN A WEAKENING
PHASE. NONETHELESS, WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY
LOOKS LIKELY LATE TONIGHT AND INTO MONDAY MORNING. THEREFORE, WILL
CONTINUE HIGH POPS FOR LATE TONIGHT. TEMPERATURES LOOK TO REMAIN
MILD WITH LOWS IN THE UPPER 60S TO THE LOWER 70S.
FOR MONDAY, SOMEWHAT OF A MORE COMPLEX FORECAST HERE AS WIDESPREAD
CONVECTION IN THE MORNING HOURS WILL LIKELY RESULT IN MORE LIMITED
INSTABILITY AS A FRONT PUSHES IN FROM THE NORTHWEST. MID-LEVEL FLOW
STILL LOOKS TO BE DECENT WITH 30-35 KT MID-LEVEL FLOW OVERSPREADING
THE REGION. HOWEVER, QUESTION REMAINS HOW MUCH CLOUD COVER WILL
LIMIT INSTABILITY. BASED ON THERMODYNAMIC AND KINEMATIC PROFILES,
MULTI-CELLULAR CONVECTION SEEMS TO BE THE PRIMARY CONVECTIVE MODE ON
MONDAY WITH GUSTY WINDS BEING THE MAIN THREAT WITH A LOWER LEVEL
THREAT OF MARGINALLY SEVERE HAIL. CLOUDS AND PRECIPITATION WILL
LIKELY HOLD TEMPERATURES DOWN WITH READINGS GENERALLY IN THE MIDDLE
80S. IF CURRENT MODEL TRENDS CONTINUE, SOME DOWNWARD ADJUSTMENT IN
MAX TEMPS MONDAY MAY BE REQUIRED IN SUBSEQUENT FORECASTS.
.LONG TERM (MONDAY NIGHT THROUGH SATURDAY)...
ISSUED AT 300 AM EDT SUN AUG 9 2015
AT THE START OF THE EXTENDED PERIOD MONDAY NIGHT, A SURFACE COLD
FRONT WILL PUSH THROUGH SOUTH-CENTRAL INDIANA AND CENTRAL KENTUCKY
AS A MID-LEVEL TROUGH DIGS ACROSS THE GREAT LAKES STATES. WHILE MUCH
OF THE DEEP-LAYERED MOISTURE WILL HAVE PUSHED TO OUR EAST, RESIDUAL
LOW-LEVEL MOISTURE AND INSTABILITY COMBINED WITH MODEST FRONTAL
CONVERGENCE SHOULD BE ENOUGH TO FORCE ISOLATED/SCATTERED CONVECTION
ALONG/AHEAD OF THE FRONT MONDAY EVENING, BEFORE WEAKENING OVERNIGHT.
THEREAFTER, THE EXTENDED PERIOD WILL BE CHARACTERIZED BY A MID-LEVEL
AVERAGE TROUGH POSITION ALONG THE EAST COAST, AND A PERSISTENT RIDGE
FROM THE SOUTHWEST U.S. NORTHWARD INTO THE NORTHERN HIGH PLAINS.
THIS WILL KEEP A DRY NORTHWEST FLOW ALOFT OVER THE OHIO VALLEY AS
HIGH PRESSURE AT THE SURFACE BUILDS FROM THE MIDWEST BEHIND THE
FRONT BEFORE SETTLING ACROSS THE OHIO VALLEY FOR THE MID AND LATTER
PORTIONS OF THIS COMING WEEK. MODELS DO SUGGEST THAT WEAK DIURNAL
INSTABILITY COULD DEVELOP TUESDAY AFTERNOON WITH COOL NORTHWEST FLOW
ALOFT, SO WILL KEEP A SLIGHT CHANCE OF SHOWERS OVER OUR SOUTHEAST
COUNTIES IN CENTRAL KY.
AS HIGH PRESSURE SETTLES IN, HIGH TEMPERATURES WILL BE SEVERAL
DEGREES BELOW NORMAL BY MID NEXT WEEK, PEAKING OUT ONLY IN THE UPPER
70S AND LOWER 80S WEDNESDAY AND THURSDAY. HUMIDITY LEVELS (SURFACE
DEWPOINTS) WILL BE LOW AS WELL. LOW TEMPERATURES THURSDAY AND FRIDAY
MORNINGS SHOULD RANGE FROM THE MID 50S TO LOWER 60S. BY NEXT
WEEKEND, TEMPERATURES SHOULD RETURN TO NEAR OR ABOVE NORMAL AS
SUMMER AIR RETURNS.
&&
.AVIATION (18Z TAF UPDATE)...
ISSUED AT 120 PM EDT SUN AUG 9 2015
CONTINUE TO SEE BANDS OF STORMS FORM UPSTREAM AND THEN FADE AS THEY
APPROACH SOUTHWEST INDIANA. MODEL AND AMDAR SOUNDINGS SHOW A STABLE
LAYER AROUND 800 MB OVER KSDF...BUT THIS AIR SHOULD BECOME MODIFIED
THROUGH THE AFTERNOON. A FEW OF THE HIGH-RES MODELS INDICATE SOME
STORMS COULD NEAR THE KSDF TERMINAL EARLIER THAN WHAT IS IN THIS
TAF, BUT WENT WITH THE MAJORITY AND HELD OFF STORM CHANCES UNTIL 3Z.
CHANCES ARE LOWER FOR THOSE STORMS MAKING IT TO KLEX/KBWG...BUT
ENOUGH TO PUT IN A PROB30 GROUP AROUND DAYBREAK MONDAY. THINK BY
LATE MORNING THERE SHOULD BE A BREAK IN THE STORM CHANCES AT EACH
SITE...BUT CANNOT RULE OUT SOME LIGHT RAINS. SWITCHED OVER TO
VICINITY SHOWERS AT THAT POINT.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
UPDATE.........RJS
SHORT TERM.....MJ
LONG TERM......TWF
AVIATION.......RJS
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
306 PM EDT SUN AUG 9 2015
.SYNOPSIS...
HIGH PRESSURE WILL GRADUALLY MOVE TO THE NORTHEAST TONIGHT. A
WARM FRONT WILL APPROACH FROM THE SOUTHWEST MONDAY AND LIFT TO THE
NORTH MONDAY NIGHT. A COLD FRONT WILL THEN SWEEP EASTWARD TUESDAY
AFTERNOON. HIGH PRESSURE BUILDS IN AGAIN BY MIDWEEK.
&&
.NEAR TERM /THROUGH MONDAY/...
BROAD BUT WEAK HIGH PRESSURE STRETCHES ALONG THE EASTERN SEABOARD
THIS AFTERNOON. A ZONAL UPPER LEVEL JET STRETCHES ACROSS THE GREAT
LAKES. THERE IS ENOUGH MOISTURE IN THE COLUMN TO PRODUCE MOSTLY
CLOUDY SKIES AT TIMES AS WELL AS ISOLATED/SCATTERED SHOWERS THIS
AFTERNOON. MOST OF THESE ARE BEING DRIVEN BY THE
TERRAIN...ALTHOUGH ONE ALSO DEVELOPED NORTH OF BALTIMORE. THUNDER
SHOULD BE LIMITED TO WESTERN AREAS IF THERE IS ANY...AS THIS IS
WHERE INSTBY IS SLIGHTLY HIGHER.
I DON/T HAVE THE HIGHEST CONFIDENCE IN THE FORECAST OVERNIGHT IN
REGARDS TO SHOWERS AS ANY FORCING WILL BE SUBTLE. MODELS HAVE HAD
SLIGHT DIFFERENCES ON HOW TO HANDLE VORT MAX APPROACHING FROM
ILLINOIS...AS WELL AS THE MAGNITUDE OF A POSSIBLE LOW LEVEL JET
DEVELOPING LATE EAST OF THE MOUNTAINS. HAVE NOT USED THE 09.12Z
12KM NAM AFTER 06Z THOUGH AS ITS RAPID CYCLOGENESIS OVER LAKE
ERIE SEEMS SPURIOUS AND IS NOT SUPPORTED ELSEWHERE. NEVERTHELESS
AS A MAJORITY OF BOTH SYNOPTIC AND MESOSCALE MODELS PAINT SOME
SORT OF PRECIP POTENTIAL THROUGH THE NIGHT...HAVE MAINTAINED THE
SLIGHT CHANCE POPS PROGRESSING EASTWARD WITH TIME. AS DEW POINTS
RISE...OVERNIGHT LOWS WILL BE LIMITED TO THE MID 60S TO LOWER 70S.
SIMILAR UNCERTAINTY IN THE COVERAGE IN SHOWERS CONTINUES THROUGH
MONDAY MORNING. THERE WILL BE BROAD ISENTROPIC LIFT IN A MOIST
ENVIRONMENT THOUGH SO CANNOT RULE OUT A FEW SHOWERS. STRONGER
FORCING ASSOCIATED WITH A DIGGING UPPER LEVEL TROUGH WILL REMAIN
TO THE WEST DURING THE MORNING. THEREFORE IT APPEARS THE CHANCE
OF SHOWERS AND SOME THUNDERSTORMS WILL INCREASE DURING THE
AFTERNOON FROM WEST TO EAST. IT WILL BE A MOSTLY CLOUDY DAY...SO
INSTBY SHOULD BE LIMITED. DEEP LAYER SHEAR ALSO DOES NOT INCREASE
INTO VERY LATE IN THE DAY. WHILE THERE MAY BE A FEW STRONGER
STORMS...MOST SHOULD JUST BE HEAVY RAINERS AS PWATS INCREASE
APPRECIABLY. HIGHS MAY MAKE IT INTO THE LOWER TO MID 80S BEFORE
THE SHOWERS BECOME MORE WIDESPREAD.
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
A WARM FRONT EXTENDING FROM LOW PRESSURE OVER THE OHIO VALLEY WILL
CROSS THE REGION OVERNIGHT MONDAY NIGHT. INSTABILITY WILL GRADUALLY
INCREASE THROUGH THE NIGHT...AND COUPLED WITH ISENTROPIC LIFT WILL
LIKELY GENERATE SCATTERED TO NUMEROUS SHOWERS AND EMBEDDED
THUNDERSTORMS. HEAVY DOWNPOURS ARE POSSIBLE WITH STRONGER ACTIVITY
AS PRECIPITABLE WATER VALUES EXCEED 1.75 INCHES. ONCE HEATING
COMMENCES TUESDAY MORNING...AS LONG AS LOW-LEVEL SHEAR ALONG THE
WARM FRONT IS STILL LINGERING THEN THERE COULD BE A BRIEF SPIN UP.
OTHERWISE...BETTER CHANCE FOR STRONG TO SEVERE STORMS WOULD BE ALONG
AND AHEAD OF A COLD FRONT TUESDAY AFTERNOON. THERE IS UNCERTAINTY AS
TO HOW FAR EAST THE FRONT GETS BY PEAK HEATING...WHICH WILL
DETERMINE WHICH AREAS HAVE THE BETTER CHANCES OF CONVECTION. OF SOME
CONCERN IS MODEL SOUNDINGS DEPICTING THE FATTER PART OF CAPE
PROFILES IN THE HAIL GROWTH ZONE /AROUND -20 C/ WHICH WOULD SUPPORT
STRONG ELEVATED CORES WITH DOWNBURSTS/HAIL. EFFECTIVE BULK SHEAR
APPROACHES 30 KT DURING THE AFTERNOON AND COULD LEND TO SOME
MULTICELLULAR ORGANIZATION/GUSTY WIND POTENTIAL AS WELL. GIVEN
UNCERTAINTIES IN FRONTAL PLACEMENT/CLOUD COVER/INSTABILITY...OVERALL
RISK APPEARS MARGINAL FOR NOW AND CONFINED TO EAST OF THE BLUE RIDGE
MOUNTAINS TUE /THOUGH AN ISOLATED STRONG STORM COULD FIND ITS WAY
OVER THE MOUNTAINS MON NIGHT FURTHER WEST/.
THE FRONT WILL MOVE OFFSHORE...ENDING THE THREAT OF SHOWERS AND
STORMS TUESDAY EVENING.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
ESSENTIALLY NOTHING HAS CHANGED SINCE THIS TIME YESTERDAY WITH
REGARDS TO FORECAST FOR THE LONG TERM. COLD FRONT THAT PASSES
THROUGH TUESDAY WILL SCOUR OUT QUALITY MOISTURE...WHICH WILL LEAVE
CWA IN AN EXTENDED PERIOD OF WARM...COMFORTABLE...AND PRECIP FREE
WEATHER.
HIGH PRESSURE BEHIND THE FRONT BUILDS IN THROUGH THE WEEK...AND WITH
LITTLE CLOUD COVER AND LOWER DEWPOINTS...EXPECT STRONG RADIATIONAL
COOLING AT NIGHT...ESPECIALLY AS THE HIGH BUILDS OVERHEAD THURSDAY
INTO FRIDAY MORNING. AS MENTIONED YESTERDAY...TEMPS ALONG OUR FAR
WESTERN BORDER COULD DROP INTO THE U40S THURSDAY AND FRIDAY MORNING.
ELSEWHERE...EXPECT LOWS GENERALLY IN THE 50S WEST OF BLUE RIDGE AND
L/M60S EAST...WITH U60S IN URBAN AREAS.
LITTLE CLOUD COVER THROUGH THE PERIOD WILL ALSO LEAD TO STRONG
DAYTIME HEATING...SO EXPECT TEMPS TO GRADUALLY RISE EACH DAY AS
AIRMASS SLOWLY MODIFIES. BY FRIDAY AND SATURDAY...HIGH TEMPS WILL
RETURN TO AOA NORMAL.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
VFR CONDITIONS WILL PREVAIL A MAJORITY OF THE TIME THROUGH THIS
AFTERNOON ALTHOUGH CIGS COULD BE AS LOW AS 4 KFT AT TIMES. SOME
SHOWERS ARE POPPING ACROSS THE MOUNTAINS...WITH MRB BEING THE MOST
LIKELY TO BE AFFECTED...BUT COULD REACH THE OTHER TERMINALS AS
WELL. HOWEVER...ANY AVIATION IMPACTS WOULD BE BRIEF. A STRAY
SHOWER WILL REMAIN POSSIBLE OVERNIGHT INTO MONDAY
MORNING...ALTHOUGH AREAL COVERAGE IS LOWER CONFIDENCE. WINDS WILL
REMAIN LESS THAN 10 KT THROUGH TONIGHT. SHOWERS AND PERHAPS A
THUNDERSTORM WILL BECOME INCREASINGLY LIKELY FROM WEST TO EAST
MONDAY AFTERNOON. BRIEF VSBY REDUCTIONS WILL BE POSSIBLE AS RAIN
COULD BE LOCALLY HEAVY. SOUTHERLY WINDS MAY GUST UP TO 15-20 KT.
IFR PSBL MON NIGHT-TUE AM W/ LWR CIGS/VSBYS IN SHRA/ISO
TSTMS AHEAD OF WARM FRONT. SELY WIND 10-15 KT AT THE
SURFACE...VEERING TO WLY AROUND 30 KT AT 2 KFT. RESTRICTIONS PSBL
TUE IN SCTD TSTMS AHEAD OF COLD FRONT. SWLY WIND 10-15 KT.
TIMING/PLACEMENT OF FRONT AND SUBSEQUENT TSTMS CHANCES/EXACT WIND
DIRECTION A BIT UNCERTAIN AT THIS TIME. FRONT MOVES OFFSHORE TUE
EVE...VFR RETURNS W/ NWLY FLOW AOB 10 KT.
VFR EXPECTED FROM TUESDAY NIGHT ONWARD UNDER HIGH PRESSURE.
&&
.MARINE...
LIGHT WINDS WILL CONTINUE UNDER HIGH PRESSURE THROUGH THIS
AFTERNOON. A STRAY SHOWER MAY CROSS THE NORTHERN BAY. BIGGEST
CHANGE TO THE FORECAST IS THAT THE PREPONDERANCE OF GUIDANCE IS NOW
SUGGESTING A LOW LEVEL JET AND SOUTHERLY CHANNELING WILL BEGIN
OVER THE BAY THIS EVENING. HAVE ISSUED A SCA UP TO POOLES ISLAND
FOR THIS. HAVE ENDED THIS AT 3 AM AS GFS AND RAP SHOW LOW LEVEL
WINDS DECREASING. SOUTHERLY FLOW WILL THEN INCREASE AGAIN DURING
THE DAY MONDAY AHEAD OF AN APPROACHING FRONT. EXPANDED THE SCA TO
ALL WATERS BEGINNING AT NOON. WHILE A SHOWER OR STORM COULD POP
UP AT NEARLY ANY TIME OF THE DAY...SUBSTANTIAL COVERAGE IS NOT
EXPECTED UNTIL AT LEAST LATE AFTERNOON.
SOUTHERLY LLJ OF ABOUT 30 KT AROUND 2000 FEET MON NIGHT
WILL LEND TO SOLID SCA GUSTS. WIND GUSTS AT THE SURFACE COULD EXCEED
30 KT IN HEAVIER ACTIVITY ESPECIALLY EARLY TUE AM. COULD BE SOME
GUSTY WINDS W/ SCTD TSTM ACTIVITY TUE PM AS WELL...BUT CONFIDENCE
TOO MARGINAL AT THIS POINT TO INCLUDE A MENTION IN THE HWO.
NO MARINE HAZARDS EXPECTED FROM WEDNESDAY THROUGH THE REMAINDER OF
THE PERIOD...AS HIGH PRESSURE DOMINATES.
&&
.TIDES/COASTAL FLOODING...
TIDAL ANOMALIES ARE NOW INCREASING ABOVE ONE FOOT AT MOST COASTAL
LOCATIONS. CONSIDERING RECENT TRENDS...IT IS LIKELY ANNAPOLIS AND
STRAITS POINT WILL EXCEED MINOR FLOOD THRESHOLDS DURING THE PM
TIDE CYCLE. A FEW OTHER SITES WILL NEED TO BE WATCHED THOUGH.
WITH SOUTHERLY/SOUTHEASTERLY FLOW...THE EXISTING ANOMALY LIKELY
PERSISTS OR BUILDS MONDAY INTO TUESDAY. A MORE WIDESPREAD COASTAL
FLOOD THREAT WILL LIKELY DEVELOP DURING THIS TIME...ESPECIALLY
DURING THE HIGHER-ASTRONOMICALLY OVERNIGHT TIDE CYCLES.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...COASTAL FLOOD ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM EDT
MONDAY FOR MDZ014.
COASTAL FLOOD ADVISORY FROM 8 PM THIS EVENING TO 1 AM EDT
MONDAY FOR MDZ017.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 3 AM EDT MONDAY
FOR ANZ531>534-537>543.
SMALL CRAFT ADVISORY FROM NOON MONDAY TO 6 AM EDT TUESDAY FOR
ANZ530>543.
&&
$$
SYNOPSIS...ADS
NEAR TERM...ADS
SHORT TERM...DFH
LONG TERM...MSE
AVIATION...ADS/MSE/DFH
MARINE...ADS/MSE/DFH
TIDES/COASTAL FLOODING...ADS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
332 PM EDT SUN AUG 9 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 308 PM EDT SUN AUG 9 2015
MUCH OF THE FOCUS ON THE SHORT TERM FORECAST IS ON THE CONVECTIVE
DEVELOPMENT EXPECTED OVER THE WEST/CENTRAL U.P. IN THE NEXT FEW
HOURS AND CONTINUING INTO THE EVENING. A LARGE AREA OF MVFR CLOUDS
HAS BEEN SETUP OVER NORTHWEST WISCONSIN AND WESTERN UPPER MICHIGAN
THIS MORNING AND INTO THE EARLY AFTERNOON HOURS. THIS HAS HELPED
SUPPRESS THE DIURNAL HEATING AND HAS KEPT ML CAPE VALUES OVER THE
WESTERN THIRD OF THE U.P. BELOW 500 J/KG. FARTHER TO THE EAST AND
ALONG THE EDGE OF THE LOW CLOUDS...DIURNAL CU HAS DEVELOPED AND RAP
ANALYSIS DATA IS SHOWING 500-1000 J/KG OF ML CAPE. HAVE STARTED TO
SEE SOME SHOWERS DEVELOP IN CENTRAL IRON COUNTY AND ALSO ALONG THE
WISCONSIN BORDER SOUTH OF BESSEMER. THESE ARE OUT AHEAD OF THE COLD
FRONT STRETCHING SOUTHWEST ACROSS WESTERN LAKE SUPERIOR AND INTO
CENTRAL MINNESOTA. A SHORTWAVE HAS BEEN MOVING THROUGH CENTRAL
MINNESOTA THIS MORNING AND INTO THE EARLY AFTERNOON HOURS...WHICH
HAS BEEN THE MAIN FOCUS OF SHOWERS AND THUNDERSTORMS THUS FAR. WITH
THE SHORTWAVE EXPECTED TO CONTINUE EASTWARD...THINK THE CWA WILL
ONLY BE BRUSHED BY THE NORTHERN EDGE...BUT WITH THE SUPPORT OF THE
WEAK COLD FRONT MOVING INTO THE WESTERN U.P. STILL THINK ISOLATED TO
SCATTERED SHOWERS AND A FEW THUNDERSTORMS ARE POSSIBLE THE REST OF
THIS AFTERNOON INTO THIS EVENING. RAP MUCAPE VALUES EXCEED 1000 J/KG
OVER THE WESTERN U.P. SO THERE IS STILL SOME SUPPORT FOR STRONGER
STORMS IF THEY CAN GET GOING. UNFORTUNATELY MID CLOUDS FROM THE
SHORTWAVE ARE MASKING THE LOWER CLOUD FIELD AND IT IS MAKING IT
DIFFICULT TO SEE HOW DEVELOPMENT IS GOING...BUT AM ABLE TO MAKE OUT
SOME SCATTERING OF THE LOW CLOUDS TO THE SOUTHWEST OF MARQUETTE
COUNTY...SO THAT MAY BE ENOUGH TO GET SHOWERS DEVELOPING FURTHER AS
THEY INTERACT WITH THE BETTER INSTABILITY JUST TO THE EAST. IN
ADDITION...HAVE SEEN SOME HINTS OF A LAKE BREEZE NEAR MARQUETTE ON
OBS AND RADAR...WHICH WILL LEAD TO SOME SHOWER DEVELOPMENT. ADJUSTED
THE FORECAST EARLIER THIS MORNING WITH THE AXIS OF HIGHEST POPS
TOWARDS THAT AREA AND WILL MAKE SLIGHT ADJUSTMENTS TO THAT AREA
(SLIGHTLY TO THE WEST AND TOWARDS THE COLD FRONT) BEFORE FINAL
ISSUANCE.
THE FRONT WILL SLOWLY MOVE EAST ACROSS THE U.P. TONIGHT AND EXIT THE
NEWBERRY/MANISTIQUE AREA A COUPLE HOURS AFTER SUNRISE. A LOT OF THE
FORECAST FOR THIS EVENING WILL DEPEND ON THE DEVELOPMENT/COVERAGE OF
THE SHOWERS AND THUNDERSTORMS OVER THE WESTERN/CENTRAL U.P....BUT
THINK THE COMBINED FRONT AND SHORTWAVE WILL KEEP THE SCATTERED
SHOWER POTENTIAL PUSHING EAST THROUGH THE AREA INTO THE FIRST PART
OF THE OVERNIGHT HOURS...ESPECIALLY OVER THE CENTRAL. THEN...EXPECT
SHOWERS TO DIMINISH OVERNIGHT AS THE COLD FRONT AND WEAK SHORTWAVE
SHIFTS OFF TO THE EAST. THAT WILL LEAVE THE AREA BETWEEN THE
DEPARTING COLD FRONT AND A HIGH BUILDING INTO THE NORTHERN PLAINS.
WITH LIGHT WINDS AND PARTLY CLOUDY TO MOSTLY CLEAR SKIES BEHIND THE
FRONT...EXPECT THERE TO BE SOME FOG DEVELOPMENT
OVERNIGHT...ESPECIALLY OVER THE CENTRAL. THE WEST AND EAST THIRDS
WILL BE A LITTLE MORE UNCERTAIN...DUE TO THE POTENTIAL FOR LESS LOW
LEVEL MOISTENING FROM RAIN AND CLOUD COVER FROM THE DEPARTING
SHORTWAVE OVER THE EAST AND INCREASING LOW LEVEL NORTH-NORTHWESTERLY
FLOW OVER THE WEST.
THOSE NORTHERLY WINDS WILL INCREASE THROUGH THE MORNING TOMORROW AS
THE FRONT MOVES AWAY FROM THE AREA AND THE HIGH BUILDS INTO THE
NORTHERLY PLAINS. OVERALL...IT SHOULDN/T BE TOO WINDY WITH MOSTLY
LOCATIONS SEEING GUSTS AROUND 10-12KTS. WITH THE WINDS AIDING MIXING
AND DIURNAL HEATING...SHOULD SEE THE FOG THAT DEVELOPS OVERNIGHT
TRANSITION TO SOME DIURNAL CU THROUGH THE MORNING AND EARLY
AFTERNOON HOURS. MODELS SHOWING LIMITED MOISTURE THAT IT IS MIXING
INTO...SO WOULDN/T EXPECT THE COVERAGE TO BE MORE THAN PARTLY
CLOUDY. THERE CONTINUES TO BE INDICATIONS IN THE HIGHER RESOLUTION
MODELS THAT ISOLATED SHOWERS WILL DEVELOP OVER THE SOUTH CENTRAL IN
THE AFTERNOON AND ALSO AROUND OR JUST SOUTHEAST OF KERY. THERE IS
BETTER MOISTURE LINGERING IN THAT AREA AND INDICATIONS OF MLCAPE
VALUES RISING TOWARDS 300 J/KG. FINALLY...DEEPER MOISTURE ARRIVES
LATE IN THE DAY FROM THE NORTHWEST AS A 700-500MB TROUGH DROPS
SOUTHEAST AROUND THE DISSIPATING JAMES BAY UPPER LOW. WITH THE
STRENGTH OF THE WAVE...COULD SEE A FEW SHOWERS DROP SOUTHEAST ACROSS
NORTHWEST LAKE SUPERIOR LATE IN THE DAY AND MAYBE APPROACH THE
KEWEENAW PENINSULA. HAVE LEFT THE SLIGHT CHANCES JUST TO THE
NORTHWEST OF THE KEWEENAW FOR NOW...AS THE BEST OPPORTUNITY WOULD
COME AFTER 00Z.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 332 PM EDT SUN AUG 9 2015
A NW FLOW BTWN AN UPR RDG IN THE PLAINS AND A DOWNSTREAM TROF OVER
ERN CANADA WL DOMINATE THE GREAT LKS EARLY THIS WEEK...BRINGING A
PERIOD OF BLO NORMAL TEMPS FOR MON NGT INTO WED. WARMER WX AND A CHC
OF SHOWERS/TS WL THEN BE THE RULE ON THU IN ADVANCE OF A COLD FNT
ASSOCIATED WITH A DISTURBANCE DROPPING SEWD THRU NW ONTARIO. EXPECT
DRY AND A BIT COOLER WX LATE IN THE WEEK WITH HI PRES TRAILING THE
FNT. THE NEXT CHC OF SHOWERS/TS AND WARMER WX WL RETURN NEXT SUN
AHEAD OF THE NEXT SHRTWV/COLD FNT TOPPING THE PERSISTENT UPR RDG IN
THE PLAINS.
MON NGT...SHRTWV DIVING SEWD IN THE NW FLOW ALF BTWN PLAINS RDG AND
ERN TROF IS FCST TO DIG THRU THE AREA. SOME OF THE MODELS SHOW SOME
WEAK DEEP LYR QVECTOR CNVGC ASSOCIATED WITH THE PVA AHEAD OF THIS
DISTURBANCE AND GENERATE SOME SPOTTY LGT PCPN OVER THE AREA...MAINLY
OVER THE HIER TERRAIN NEAR LK SUP WITH UPSLOPE N WINDS. BUT ABSENCE
OF STRONGER FORCING AND ARRIVAL OF THIS DISTURBANCE DURING PERIOD OF
NOCTURNAL COOLING WL LIMIT INTENSITY AND COVERAGE OF ANY SHOWERS. DO
EXPECT MORE LO CLDS IN THESE UPSLOPE AREAS WITH AN INCRS IN LLVL RH
AS H85 TEMPS WITHIN THERMAL TROF FALL TO 8-10C BY 12Z TUE. STEADY N
WINDS WL LIMIT THE DIURNAL TEMP FALL DESPITE THE LLVL COOLING TREND.
MOST PLACES SHOULD SEE MINS IN THE 50S...WITH THE LOWER TEMPS AT THE
COOLER SPOTS OVER THE INTERIOR W HALF WHERE THE WINDS WL BE A BIT
LIGHTER CLOSER TO SFC HI PRES RDG BLDG INTO MN.
TUE/TUE NGT...EXPECT DRY WX TO PREVAIL DURING THIS TIME UNDER
CONFLUENT NW FLOW ALF/DEEP LYR QVECTOR DVGC/SUBSIDENCE LEFT IN THE
WAKE OF EXITING SHRTWV. SC IN THE UPSLOPE AREAS ON TUE MRNG SHOULD
EXPAND WITH DAYTIME HEATING UNDER THERMAL TROF...BUT CLOSER APRCH OF
SFC HI PRES FCST TO ARRIVE OVER THE W BY 00Z WED/INCRSGLY ACYC LLVL
FLOW/LOWERING SUBSIDENCE INVRN WL LIKELY RESULT IN MORE SUNSHINE W-E
THRU THE AFTN. UNDER MOCLR SKIES...TUE NGT WL BE COOL ESPECIALLY
OVER THE INTERIOR W HALF WITH LIGHTER WINDS CLOSER TO SFC HI PRES
RDG SINKING INTO WI. BUT WITH MIN PWAT NOT MUCH BLO 0.75 INCH IN
THIS AREA...DO NOT EXPECT MIN TEMPS TO BE TOO CHILLY.
WED/WED NGT...SFC HI PRES IS FCST TO SINK S INTO THE MID MS RIVER
VALLEY THRU THIS TIME. AS THE MSLP FALLS OVER NW ONTARIO IN ADVANCE
OF SHRTWV RIDING OVER THE TOP OF PLAINS RDG INTO FAR NW ONTARIO...
UPR MI WL BE DOMINATED BY AN INCRSG WSW FLOW. EXPECT SOME CLDS
ASSOCIATED WITH BAND OF INCRSG WAA/ISENTROPIC ASCENT BEST SHOWN ON
THE 300-305K SFCS TO IMPACT THE UPR LKS WED AFTN/EVNG. MANY OF THE
MODELS GENERATE SOME PCPN AS WELL...BUT RELATIVE DRYNESS OF THE
LLVLS AND MODEST PWAT FCST NEAR 1 INCH /ABOUT NORMAL/ WARRANT ONLY
LO CHC POPS.
THU/THU NGT...SHRTWV OVER FAR NW ONTARIO AT 12Z THU IS PROGGED TO
SLIDE SE INTO WRN QUEBEC THU NGT AND DRAG A COLD FNT ACRS UPR MI
SOMETIME THU AFTN/EVNG. ARRIVAL OF THIS BNDRY/BAND OF MODEST DEEP
LYR FORCING AT A TIME WHEN DAYTIME HEATING WL HAVE AN IMPACT FAVORS
SOME SHOWERS/TS...BUT ABSENCE OF MUCH IN THE WAY OF HGT FALLS WELL
TO THE SW OF TRACK OF SHRTWV/SHARPEST FORCING...QUESTIONS ABOUT
DEGREE OF MSTR INFLOW AHEAD OF THE FNT AND TIMING DIFFERENCES AMONG
THE MODELS ON FROPA TIMING WARRANT NO HIER THAN LO CHC POPS ATTM.
THU LOOKS TO BE A WARM DAY WITH H85 TEMPS PUSHING 18-20C AHEAD OF
THE FNT.
EXTENDED...HI PRES TRAILING THE COLD FROPA WL BRING MOCLR WX FOR FRI
AND SAT. FRI WL BE COOLER WITH H85 TEMPS DIPPING TO ARND 14C...BUT
THEN SAT WL TURN WARMER AS THE HI SHIFTS TO THE E AND RETURN SSW
FLOW LIFTS H85 TEMPS UP TO 16C. THE NEXT CHC OF SHOWERS/TS WL ARRIVE
ON SUN AHEAD OF NEXT DISTURBANCE RIDING OVER THE PLAINS RDG.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 150 PM EDT SUN AUG 9 2015
IFR TO MVFR CLOUDS THIS MORNING OVER THE WESTERN U.P. SHOULD LIMIT
THE THUNDER POTENTIAL AT KIWD/KCMX THIS AFTERNOON...BUT THE
NORTHERN EDGE OF A WEAK DISTURBANCE MOVING THROUGH THE AREA THIS
AFTERNOON COULD LEAD TO A STRAY SHOWER AT KIWD. HAVE SEEN CEILINGS
RISING OVER THE LAST TWO HOURS AT THOSE SITES AND THEY SHOULD
TRANSITION TO LOW END VFR THIS AFTERNOON. FARTHER TO THE EAST AT
KSAW...MORE SUNSHINE THIS MORNING HAS STARTED TO PRODUCE A LAKE
BREEZE NEAR MARQUETTE AND EXPECT THAT TO MOVE INLAND. PLANNING ON
SHOWERS AND THUNDERSTORMS DEVELOPING ALONG THAT BREEZE AND THIS
AFTERNOON AND PRODUCE A THUNDERSTORM AT KSAW. DID INCLUDE A TWO
HOUR PERIOD DURING GREATEST CONFIDENCE...AND COULD SEE CONDITIONS
FALL TO MVFR OR EVEN IFR DURING THE THUNDERSTORM.
ONCE THE COLD FRONT MOVES THROUGH THE AREA TONIGHT AND BREAKS IN
THE CLOUDS OCCUR...BELIEVE GROUND FOG WILL DEVELOP AT ALL THREE
SITES. WILL SHOW THE WORST CONDITIONS AT KSAW WITH THE HELP OF RAIN
THIS AFTERNOON AND THE LIGHTEST WINDS. DIDN/T GO TOO LOW OVER THE
WEST SITES...AS LOW LEVEL WINDS WILL SLOWLY BE INCREASING THROUGH
THE NIGHT AND LEAD TO MORE MIXING INTO THE DRIER AIR ALOFT. WILL
NEED TO WATCH THE FOG OVER THE WESTERN LAKE...AS THAT COULD LEAD TO
LOWER CONDITIONS THAN FORECAST FOR KCMX. FINALLY FOR
TOMORROW...EXPECT CONDITIONS IMPROVING TO VFR THROUGH THE MORNING
HOURS AS THE AREA IS IN BETWEEN THE DEPARTING FRONT AND ANOTHER
UPPER LEVEL DISTURBANCE ARRIVING LATE MONDAY AFTERNOON AND EVENING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 308 PM EDT SUN AUG 9 2015
A COLD FRONT MOVING ACROSS WEST-CENTRAL LAKE SUPERIOR AT THIS TIME
WILL PUSH EAST ACROSS THE REST OF THE LAKE TONIGHT WILL LEAD TO A
WIND SHIFT FROM SOUTHERLY TO NORTHWESTERLY. WITH GENERALLY A WEAK
PRES GRADIENT...WINDS SHOULD REMAIN UNDER 20KT THRU MON. PATCHY TO
AREAS OF FOG HAS BEEN OBSERVED ON SATELLITE FOR PORTIONS OF THE
LAKE AND EXPECT THAT TO DIMINISH TONIGHT INTO MONDAY AS SLIGHTLY
DRIER AIR ARRIVES BEHIND THE FRONT. MON NIGHT/TUE...THE GRADIENT
TIGHTENS A BIT AHEAD OF APPROACHING SFC HIGH PRES...SO WINDS OVER
THE E HALF OF LAKE SUPERIOR WILL PROBABLY BEGIN TO GUST MORE
FREQUENTLY TO AROUND 20KT. ARRIVAL OF SFC HIGH PRES RIDGE WILL
RESULT IN WINDS UNDER 15KT TUE NIGHT/WED. WINDS WILL THEN INCREASE
SOME OUT OF THE SOUTHWEST INTO THU AHEAD OF THE NEXT APPROACHING
COLD FRONT. THAT FRONT WILL SHIFT WINDS TO THE NORTHWEST FOR
FRIDAY...BUT SHOULD STAY BELOW 20KTS AT HIGH PRESSURE BUILDS BACK
OVER THE AREA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...KC
AVIATION...SRF
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
308 PM EDT SUN AUG 9 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 308 PM EDT SUN AUG 9 2015
MUCH OF THE FOCUS ON THE SHORT TERM FORECAST IS ON THE CONVECTIVE
DEVELOPMENT EXPECTED OVER THE WEST/CENTRAL U.P. IN THE NEXT FEW
HOURS AND CONTINUING INTO THE EVENING. A LARGE AREA OF MVFR CLOUDS
HAS BEEN SETUP OVER NORTHWEST WISCONSIN AND WESTERN UPPER MICHIGAN
THIS MORNING AND INTO THE EARLY AFTERNOON HOURS. THIS HAS HELPED
SUPPRESS THE DIURNAL HEATING AND HAS KEPT ML CAPE VALUES OVER THE
WESTERN THIRD OF THE U.P. BELOW 500 J/KG. FARTHER TO THE EAST AND
ALONG THE EDGE OF THE LOW CLOUDS...DIURNAL CU HAS DEVELOPED AND RAP
ANALYSIS DATA IS SHOWING 500-1000 J/KG OF ML CAPE. HAVE STARTED TO
SEE SOME SHOWERS DEVELOP IN CENTRAL IRON COUNTY AND ALSO ALONG THE
WISCONSIN BORDER SOUTH OF BESSEMER. THESE ARE OUT AHEAD OF THE COLD
FRONT STRETCHING SOUTHWEST ACROSS WESTERN LAKE SUPERIOR AND INTO
CENTRAL MINNESOTA. A SHORTWAVE HAS BEEN MOVING THROUGH CENTRAL
MINNESOTA THIS MORNING AND INTO THE EARLY AFTERNOON HOURS...WHICH
HAS BEEN THE MAIN FOCUS OF SHOWERS AND THUNDERSTORMS THUS FAR. WITH
THE SHORTWAVE EXPECTED TO CONTINUE EASTWARD...THINK THE CWA WILL
ONLY BE BRUSHED BY THE NORTHERN EDGE...BUT WITH THE SUPPORT OF THE
WEAK COLD FRONT MOVING INTO THE WESTERN U.P. STILL THINK ISOLATED TO
SCATTERED SHOWERS AND A FEW THUNDERSTORMS ARE POSSIBLE THE REST OF
THIS AFTERNOON INTO THIS EVENING. RAP MUCAPE VALUES EXCEED 1000 J/KG
OVER THE WESTERN U.P. SO THERE IS STILL SOME SUPPORT FOR STRONGER
STORMS IF THEY CAN GET GOING. UNFORTUNATELY MID CLOUDS FROM THE
SHORTWAVE ARE MASKING THE LOWER CLOUD FIELD AND IT IS MAKING IT
DIFFICULT TO SEE HOW DEVELOPMENT IS GOING...BUT AM ABLE TO MAKE OUT
SOME SCATTERING OF THE LOW CLOUDS TO THE SOUTHWEST OF MARQUETTE
COUNTY...SO THAT MAY BE ENOUGH TO GET SHOWERS DEVELOPING FURTHER AS
THEY INTERACT WITH THE BETTER INSTABILITY JUST TO THE EAST. IN
ADDITION...HAVE SEEN SOME HINTS OF A LAKE BREEZE NEAR MARQUETTE ON
OBS AND RADAR...WHICH WILL LEAD TO SOME SHOWER DEVELOPMENT. ADJUSTED
THE FORECAST EARLIER THIS MORNING WITH THE AXIS OF HIGHEST POPS
TOWARDS THAT AREA AND WILL MAKE SLIGHT ADJUSTMENTS TO THAT AREA
(SLIGHTLY TO THE WEST AND TOWARDS THE COLD FRONT) BEFORE FINAL
ISSUANCE.
THE FRONT WILL SLOWLY MOVE EAST ACROSS THE U.P. TONIGHT AND EXIT THE
NEWBERRY/MANISTIQUE AREA A COUPLE HOURS AFTER SUNRISE. A LOT OF THE
FORECAST FOR THIS EVENING WILL DEPEND ON THE DEVELOPMENT/COVERAGE OF
THE SHOWERS AND THUNDERSTORMS OVER THE WESTERN/CENTRAL U.P....BUT
THINK THE COMBINED FRONT AND SHORTWAVE WILL KEEP THE SCATTERED
SHOWER POTENTIAL PUSHING EAST THROUGH THE AREA INTO THE FIRST PART
OF THE OVERNIGHT HOURS...ESPECIALLY OVER THE CENTRAL. THEN...EXPECT
SHOWERS TO DIMINISH OVERNIGHT AS THE COLD FRONT AND WEAK SHORTWAVE
SHIFTS OFF TO THE EAST. THAT WILL LEAVE THE AREA BETWEEN THE
DEPARTING COLD FRONT AND A HIGH BUILDING INTO THE NORTHERN PLAINS.
WITH LIGHT WINDS AND PARTLY CLOUDY TO MOSTLY CLEAR SKIES BEHIND THE
FRONT...EXPECT THERE TO BE SOME FOG DEVELOPMENT
OVERNIGHT...ESPECIALLY OVER THE CENTRAL. THE WEST AND EAST THIRDS
WILL BE A LITTLE MORE UNCERTAIN...DUE TO THE POTENTIAL FOR LESS LOW
LEVEL MOISTENING FROM RAIN AND CLOUD COVER FROM THE DEPARTING
SHORTWAVE OVER THE EAST AND INCREASING LOW LEVEL NORTH-NORTHWESTERLY
FLOW OVER THE WEST.
THOSE NORTHERLY WINDS WILL INCREASE THROUGH THE MORNING TOMORROW AS
THE FRONT MOVES AWAY FROM THE AREA AND THE HIGH BUILDS INTO THE
NORTHERLY PLAINS. OVERALL...IT SHOULDN/T BE TOO WINDY WITH MOSTLY
LOCATIONS SEEING GUSTS AROUND 10-12KTS. WITH THE WINDS AIDING MIXING
AND DIURNAL HEATING...SHOULD SEE THE FOG THAT DEVELOPS OVERNIGHT
TRANSITION TO SOME DIURNAL CU THROUGH THE MORNING AND EARLY
AFTERNOON HOURS. MODELS SHOWING LIMITED MOISTURE THAT IT IS MIXING
INTO...SO WOULDN/T EXPECT THE COVERAGE TO BE MORE THAN PARTLY
CLOUDY. THERE CONTINUES TO BE INDICATIONS IN THE HIGHER RESOLUTION
MODELS THAT ISOLATED SHOWERS WILL DEVELOP OVER THE SOUTH CENTRAL IN
THE AFTERNOON AND ALSO AROUND OR JUST SOUTHEAST OF KERY. THERE IS
BETTER MOISTURE LINGERING IN THAT AREA AND INDICATIONS OF MLCAPE
VALUES RISING TOWARDS 300 J/KG. FINALLY...DEEPER MOISTURE ARRIVES
LATE IN THE DAY FROM THE NORTHWEST AS A 700-500MB TROUGH DROPS
SOUTHEAST AROUND THE DISSIPATING JAMES BAY UPPER LOW. WITH THE
STRENGTH OF THE WAVE...COULD SEE A FEW SHOWERS DROP SOUTHEAST ACROSS
NORTHWEST LAKE SUPERIOR LATE IN THE DAY AND MAYBE APPROACH THE
KEWEENAW PENINSULA. HAVE LEFT THE SLIGHT CHANCES JUST TO THE
NORTHWEST OF THE KEWEENAW FOR NOW...AS THE BEST OPPORTUNITY WOULD
COME AFTER 00Z.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 444 AM EDT SUN AUG 9 2015
AT 12Z MONDAY THE APEX OF THE 500MB TROUGH /EXTENDING FROM THE LOW
OVER JAMES BAY/ WILL BE OVERHEAD...WITH SHOWERS EXITING THE E CWA.
A SECONDARY SHORTWAVE SWINGING AROUND THE MAIN TROUGH WILL PUSH IN
FROM THE NW MONDAY NIGHT. WITH LIMITED MOISTURE...DO NOT EXPECT MUCH
IN THE WAY OF PRECIP. MODELS DO SHOW SOME INCREASE IN LOW LEVEL
MOISTURE...BELOW 800MB...WITH THE BEST MOISTURE ASSISTED BY N-NNW
FLOW OVER THE E THIRD OF UPPER MI.
EXPECT A MAINLY N WIND TO REMAIN JUST ABOVE THE SFC THROUGH THE
FIRST HALF OF THE WORK WEEK. 850MB TEMPS OF 8-11C WILL HELP KEEP
AFTERNOON SFC TEMPS IN THE 70S MONDAY-WEDNESDAY. AT THIS POINT
TUESDAY LOOKS TO BE THE COOLEST DAY...WITH A FEW READINGS IN THE
UPPER 60S ALONG LAKE SUPERIOR AS A LARGE AREA OF HIGH PRESSURE AT
THE SFC SETTLES OVERHEAD.
THE BROAD 500MB TROUGH WILL EXIT E WEDNESDAY...WITH RIDGING BUILDING
ACROSS THE UPPER GREAT LAKES REGION. THE DRY WEATHER WILL BE SHORT
LIVED AS A SLIGHT CHANCE OF RETURNS OVER LAKE SUPERIOR WEDNESDAY
NIGHT...AS THE 500MB RIDGE BECOMES SUPPRESSED SETTING THE STAGE FOR
NW FLOW ALOFT AND ADDITIONAL DISTURBANCES/UNSETTLED WX THROUGH
THURSDAY NIGHT. THE SFC LOW WELL TO OUR N IN CANADA WILL DRAG A COLD
FRONT NW-SE FROM AROUND 21Z THURSDAY TO 12Z FRIDAY.
DRY WEATHER SHOULD RETURN AGAIN AS THE COLD FRONT SLIPS ACROSS LOWER
MI FRIDAY AND HIGH PRESSURE BUILDS IN FOR THE START OF THE WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 150 PM EDT SUN AUG 9 2015
IFR TO MVFR CLOUDS THIS MORNING OVER THE WESTERN U.P. SHOULD LIMIT
THE THUNDER POTENTIAL AT KIWD/KCMX THIS AFTERNOON...BUT THE
NORTHERN EDGE OF A WEAK DISTURBANCE MOVING THROUGH THE AREA THIS
AFTERNOON COULD LEAD TO A STRAY SHOWER AT KIWD. HAVE SEEN CEILINGS
RISING OVER THE LAST TWO HOURS AT THOSE SITES AND THEY SHOULD
TRANSITION TO LOW END VFR THIS AFTERNOON. FARTHER TO THE EAST AT
KSAW...MORE SUNSHINE THIS MORNING HAS STARTED TO PRODUCE A LAKE
BREEZE NEAR MARQUETTE AND EXPECT THAT TO MOVE INLAND. PLANNING ON
SHOWERS AND THUNDERSTORMS DEVELOPING ALONG THAT BREEZE AND THIS
AFTERNOON AND PRODUCE A THUNDERSTORM AT KSAW. DID INCLUDE A TWO
HOUR PERIOD DURING GREATEST CONFIDENCE...AND COULD SEE CONDITIONS
FALL TO MVFR OR EVEN IFR DURING THE THUNDERSTORM.
ONCE THE COLD FRONT MOVES THROUGH THE AREA TONIGHT AND BREAKS IN
THE CLOUDS OCCUR...BELIEVE GROUND FOG WILL DEVELOP AT ALL THREE
SITES. WILL SHOW THE WORST CONDITIONS AT KSAW WITH THE HELP OF RAIN
THIS AFTERNOON AND THE LIGHTEST WINDS. DIDN/T GO TOO LOW OVER THE
WEST SITES...AS LOW LEVEL WINDS WILL SLOWLY BE INCREASING THROUGH
THE NIGHT AND LEAD TO MORE MIXING INTO THE DRIER AIR ALOFT. WILL
NEED TO WATCH THE FOG OVER THE WESTERN LAKE...AS THAT COULD LEAD TO
LOWER CONDITIONS THAN FORECAST FOR KCMX. FINALLY FOR
TOMORROW...EXPECT CONDITIONS IMPROVING TO VFR THROUGH THE MORNING
HOURS AS THE AREA IS IN BETWEEN THE DEPARTING FRONT AND ANOTHER
UPPER LEVEL DISTURBANCE ARRIVING LATE MONDAY AFTERNOON AND EVENING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 308 PM EDT SUN AUG 9 2015
A COLD FRONT MOVING ACROSS WEST-CENTRAL LAKE SUPERIOR AT THIS TIME
WILL PUSH EAST ACROSS THE REST OF THE LAKE TONIGHT WILL LEAD TO A
WIND SHIFT FROM SOUTHERLY TO NORTHWESTERLY. WITH GENERALLY A WEAK
PRES GRADIENT...WINDS SHOULD REMAIN UNDER 20KT THRU MON. PATCHY TO
AREAS OF FOG HAS BEEN OBSERVED ON SATELLITE FOR PORTIONS OF THE
LAKE AND EXPECT THAT TO DIMINISH TONIGHT INTO MONDAY AS SLIGHTLY
DRIER AIR ARRIVES BEHIND THE FRONT. MON NIGHT/TUE...THE GRADIENT
TIGHTENS A BIT AHEAD OF APPROACHING SFC HIGH PRES...SO WINDS OVER
THE E HALF OF LAKE SUPERIOR WILL PROBABLY BEGIN TO GUST MORE
FREQUENTLY TO AROUND 20KT. ARRIVAL OF SFC HIGH PRES RIDGE WILL
RESULT IN WINDS UNDER 15KT TUE NIGHT/WED. WINDS WILL THEN INCREASE
SOME OUT OF THE SOUTHWEST INTO THU AHEAD OF THE NEXT APPROACHING
COLD FRONT. THAT FRONT WILL SHIFT WINDS TO THE NORTHWEST FOR
FRIDAY...BUT SHOULD STAY BELOW 20KTS AT HIGH PRESSURE BUILDS BACK
OVER THE AREA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...KF
AVIATION...SRF
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
150 PM EDT SUN AUG 9 2015
.UPDATE...
ISSUED AT 1050 AM EDT SUN AUG 9 2015
ABUNDANT LOW CLOUDS ARE LOCATED OUT AHEAD OF THE COLD FRONT WHICH
IS STRETCHING FROM THUNDER BAY...ALONG THE WESTERN LAKE SUPERIOR
SHORELINE AND THEN SOUTHWEST INTO CENTRAL MINNESOTA. STARTING TO
HAVE SOME CONCERNS THAT THESE WIDESPREAD AND FAIRLY THICK CLOUDS
WILL HAVE SOME DIFFICULTY BURNING OFF THROUGH THE DAY...WHICH WOULD
LIMIT INSTABILITY AND LIKELY THUNDERSTORM DEVELOPMENT OVER PARTS OF
THE WESTERN U.P.. IN ADDITION...A WEAK SHORTWAVE MOVING EAST
THROUGH CENTRAL MINNESOTA IS PRODUCING LIGHT SHOWERS AND PLENTY OF
MID CLOUDS. THAT WAVE AND ITS ASSOCIATED FEATURES SHOULD MOVE EAST
THROUGH THE UPPER GREAT LAKES REGION THIS AFTERNOON INTO THE
EVENING HOURS. WITH THAT FEATURE MOVING THROUGH...WON/T DEVIATE TOO
MUCH FROM THE GOING FORECAST/POPS AT THIS POINT...BUT MAY NEED TO
FOCUS DEVELOPMENT (POPS) ON THE EASTERN EDGE OF THE CLOUDS AND MORE
INTO THE CENTRAL U.P. WHERE THE INSTABILITY WILL BE GREATEST. THAT
WOULD BE MORE IN LINE WITH THE LATEST HRRR/RAP RUNS...WHICH HAVE THE
RIBBON OF BEST MLCAPE VALUES ALONG THAT DIFFERENTIAL HEATING GRADIENT
(KSAW TO CRYSTAL FALLS).
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 532 AM EDT SUN AUG 9 2015
WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A VIGOROUS SHORTWAVE
MOVING ACROSS NRN ONTARIO. SEVERAL OTHER SHORTWAVES ACCOMPANIED BY
SHRA/TSTMS ARE NOTED MOVING ACROSS THE NRN AND CNTRL PLAINS. TAIL
END OF FORCING ASSOCIATED WITH NRN ONTARIO SHORTWAVE OVERTOP 850MB
THETA-E RIDGE HAS BEEN SUPPORTING ISOLD/SCT SHRA/TSTM DEVELOPMENT
OVE WRN UPPER MI SINCE SHORTLY AFTER MIDNIGHT. DESPITE LACK OF
INSTABILITY (MUCAPE NO HIGHER THAN 400J/KG)...A FEW OF THE STORMS
WERE FAIRLY STRONG AND LIKELY PRODUCED AT LEAST PEA-SIZE HAIL. RADAR
ESTIMATED INSTANTANEOUS PCPN RATES HAVE BEEN PRETTY IMPRESSIVE AS
WELL...THOUGH RAINFALL CORES HAVE BEEN VERY SMALL.
00Z MODEL RUNS INCLUDING HOURLY RAP/HRRR RUNS SINCE 00Z INDICATE
ONGOING ISOLD/SCT SHRA/TSTMS WILL PROBABLY PERSIST AND REACH CNTRL
UPPER MI BEFORE DIMINISHING AND PERHAPS ENDING FOR THE MOST PART.
ATTENTION THEN TURNS TO THE AFTN. BUILDING INSTABILITY AND
APPROACHING COLD FRONT WILL SPARK A NEW ROUND OF SHRA/TSTMS WITH
MODELS POINTING TOWARD BARAGA/MARQUETTE/IRON COUNTIES AS THE LIKELY
FOCAL AREA FOR GREATEST COVERAGE OF DEVELOPMENT. NAM CONTINUES TO BE
VERY AGGRESSIVE BUILDING MLCAPES TO OVER 1500J/KG OVER WRN UPPER MI
AND AS HIGH AS NEARLY 2500J/KG. GFS TOPS OUT AROUND 1000J/KG WHILE
RECENT RAP RUNS ONLY TOP OUT NEAR 500J/KG. 21Z SREF INDICATES ABOUT
A 30PCT CHANCE OF MLCAPES INCREASING TO OVER 1000J/KG...SO THE NAM
DEFINITELY LOOKS LIKE A HIGH OUTLIER. A REASONABLE EXPECTATION IS
PROBABLY MLCAPES OF 500-1000J/KG. WITH DEEP LAYER SHEAR TOPPING OUT
AROUND 25KT...SVR RISK APPEARS MINIMAL...UNLESS INSTABILITY BUILDS
HIGHER THAN CURRENTLY EXPECTED. SOME SMALL HAIL WILL BE POSSIBLE
WITH THE STRONGEST STORMS. ALSO...EXPECT BRIEF LOCALLY HVY RAINFALL.
SHRA/TSTMS WILL SHIFT E TONIGHT AND DIMINISH. LIGHT WINDS IN THE
VCNTY OF THE PASSING FRONT ALONG WITH EXPECTED RAINFALL SHOULD
RESULT IN FOG DEVELOPING...ESPECIALLY ACROSS SCNTRL/SE UPPER MI.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 444 AM EDT SUN AUG 9 2015
AT 12Z MONDAY THE APEX OF THE 500MB TROUGH /EXTENDING FROM THE LOW
OVER JAMES BAY/ WILL BE OVERHEAD...WITH SHOWERS EXITING THE E CWA.
A SECONDARY SHORTWAVE SWINGING AROUND THE MAIN TROUGH WILL PUSH IN
FROM THE NW MONDAY NIGHT. WITH LIMITED MOISTURE...DO NOT EXPECT MUCH
IN THE WAY OF PRECIP. MODELS DO SHOW SOME INCREASE IN LOW LEVEL
MOISTURE...BELOW 800MB...WITH THE BEST MOISTURE ASSISTED BY N-NNW
FLOW OVER THE E THIRD OF UPPER MI.
EXPECT A MAINLY N WIND TO REMAIN JUST ABOVE THE SFC THROUGH THE
FIRST HALF OF THE WORK WEEK. 850MB TEMPS OF 8-11C WILL HELP KEEP
AFTERNOON SFC TEMPS IN THE 70S MONDAY-WEDNESDAY. AT THIS POINT
TUESDAY LOOKS TO BE THE COOLEST DAY...WITH A FEW READINGS IN THE
UPPER 60S ALONG LAKE SUPERIOR AS A LARGE AREA OF HIGH PRESSURE AT
THE SFC SETTLES OVERHEAD.
THE BROAD 500MB TROUGH WILL EXIT E WEDNESDAY...WITH RIDGING BUILDING
ACROSS THE UPPER GREAT LAKES REGION. THE DRY WEATHER WILL BE SHORT
LIVED AS A SLIGHT CHANCE OF RETURNS OVER LAKE SUPERIOR WEDNESDAY
NIGHT...AS THE 500MB RIDGE BECOMES SUPPRESSED SETTING THE STAGE FOR
NW FLOW ALOFT AND ADDITIONAL DISTURBANCES/UNSETTLED WX THROUGH
THURSDAY NIGHT. THE SFC LOW WELL TO OUR N IN CANADA WILL DRAG A COLD
FRONT NW-SE FROM AROUND 21Z THURSDAY TO 12Z FRIDAY.
DRY WEATHER SHOULD RETURN AGAIN AS THE COLD FRONT SLIPS ACROSS LOWER
MI FRIDAY AND HIGH PRESSURE BUILDS IN FOR THE START OF THE WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 150 PM EDT SUN AUG 9 2015
IFR TO MVFR CLOUDS THIS MORNING OVER THE WESTERN U.P. SHOULD LIMIT
THE THUNDER POTENTIAL AT KIWD/KCMX THIS AFTERNOON...BUT THE
NORTHERN EDGE OF A WEAK DISTURBANCE MOVING THROUGH THE AREA THIS
AFTERNOON COULD LEAD TO A STRAY SHOWER AT KIWD. HAVE SEEN CEILINGS
RISING OVER THE LAST TWO HOURS AT THOSE SITES AND THEY SHOULD
TRANSITION TO LOW END VFR THIS AFTERNOON. FARTHER TO THE EAST AT
KSAW...MORE SUNSHINE THIS MORNING HAS STARTED TO PRODUCE A LAKE
BREEZE NEAR MARQUETTE AND EXPECT THAT TO MOVE INLAND. PLANNING ON
SHOWERS AND THUNDERSTORMS DEVELOPING ALONG THAT BREEZE AND THIS
AFTERNOON AND PRODUCE A THUNDERSTORM AT KSAW. DID INCLUDE A TWO
HOUR PERIOD DURING GREATEST CONFIDENCE...AND COULD SEE CONDITIONS
FALL TO MVFR OR EVEN IFR DURING THE THUNDERSTORM.
ONCE THE COLD FRONT MOVES THROUGH THE AREA TONIGHT AND BREAKS IN
THE CLOUDS OCCUR...BELIEVE GROUND FOG WILL DEVELOP AT ALL THREE
SITES. WILL SHOW THE WORST CONDITIONS AT KSAW WITH THE HELP OF RAIN
THIS AFTERNOON AND THE LIGHTEST WINDS. DIDN/T GO TOO LOW OVER THE
WEST SITES...AS LOW LEVEL WINDS WILL SLOWLY BE INCREASING THROUGH
THE NIGHT AND LEAD TO MORE MIXING INTO THE DRIER AIR ALOFT. WILL
NEED TO WATCH THE FOG OVER THE WESTERN LAKE...AS THAT COULD LEAD TO
LOWER CONDITIONS THAN FORECAST FOR KCMX. FINALLY FOR
TOMORROW...EXPECT CONDITIONS IMPROVING TO VFR THROUGH THE MORNING
HOURS AS THE AREA IS IN BETWEEN THE DEPARTING FRONT AND ANOTHER
UPPER LEVEL DISTURBANCE ARRIVING LATE MONDAY AFTERNOON AND EVENING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 532 AM EDT SUN AUG 9 2015
COLD FRONT MOVING ACROSS LAKE SUPERIOR THIS AFTN AND TONIGHT WILL
LEAD TO A WIND SHIFT FROM SOUTHERLY TO NORTHWESTERLY. WITH GENERALLY
A WEAK PRES GRADIENT...WINDS SHOULD REMAIN UNDER 20KT TODAY THRU
MON. MON NIGHT/TUE...GRADIENT TIGHTENS A BIT AHEAD OF APPROACHING
SFC HIGH PRES...SO WINDS OVER THE E HALF OF LAKE SUPERIOR WILL
PROBABLY BEGIN TO GUST MORE FREQUENTLY TO AROUND 20KT. ARRIVAL OF
SFC HIGH PRES RIDGE WILL RESULT IN WINDS UNDER 15KT TUE NIGHT/WED.
WINDS WILL THEN INCREASE SOME INTO THU AHEAD OF THE NEXT APPROACHING
COLD FRONT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...SRF
SHORT TERM...ROLFSON
LONG TERM...KF
AVIATION...SRF
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
336 PM CDT SUN AUG 9 2015
.SHORT TERM...(TONIGHT THROUGH WEDNESDAY)
ISSUED AT 333 PM CDT SUN AUG 9 2015
CHANCE FOR THUNDERSTORMS AND THEIR SEVERITY TONIGHT ARE THE PRIMARY
FORECAST CONCERNS.
THUNDERSTORMS WERE FIRING AT MID AFTERNOON ALONG A WEAK SURFACE
BOUNDARY STRETCHING FROM SOUTHEAST SOUTH DAKOTA INTO WESTERN
NEBRASKA. THESE STORMS HAVE PLENTY OF INSTABILITY AND SHEAR TO FEED
ON...SOME 2500 J/KG OF MLCAPE AND 40KT OF EFFECTIVE BULK SHEAR...AS
PER LATEST RAP OBJECTIVE ANALYSIS. ALREADY GETTING REPORTS OF SEVERE
HAIL JUST WEST OF OUR AREA WHERE VIGOROUS UPDRAFTS WERE SEEN. AND
FREEZING LEVELS ARE QUITE A BIT LOWER THAN LAST EVENING. SO A
CONTINUED HAIL THREAT IS CERTAINLY EXPECTED...WITH MODEST MICROBURST
POTENTIAL ALSO NOTED ON RAP PROGS.
PERHAPS A BIGGER SHOW WITH POTENTIALLY MORE WIDESPREAD SEVERE LATER
THIS EVENING IS POSSIBLE. MID LEVEL SHORTWAVE DIVING INTO WESTERN
SOUTH DAKOTA WILL CONTINUE SOUTHEAST THIS EVENING...PUSHING A COLD
FRONT ALONG WITH IT. SHEAR PROFILES SHOULD ACTUALLY INCREASE IN
MAGNITUDE GIVEN MID LEVEL SPEED MAX TIED TO WAVE. SHEAR VECTORS ARE
LINING UP NEARLY PARALLEL WITH EXPECTED FRONTAL/CONVECTIVE
LINE...SUPPORTING MORE OF A LINEAR STORM MODE. WIND
FIELDS...PREDICTED DOWNDRAFT CAPE AND LAYER THETA-E DIFFERENCES
APPROACHING 30 ALL SUGGEST SEVERE WIND POTENTIAL AS LINE RACES INTO
EASTERN NEBRASKA. SEVERAL MESOSCALE HI-RES MODELS ARE OFFERING
VARIED OPINIONS AROUND THIS LINE OF THINKING...SO WILL HIT EVENING
THUNDER CHANCES PRETTY HARD. EXPECT STORMS TO SLOWLY DIE OFF LATER
THIS EVENING AND OVERNIGHT AS THEY APPROACH INTERSTATE 80 AND
BEYOND...HOWEVER SEVERE THREAT APPEARS TO LINGER FOR SOME TIME AFTER
DARK.
BY MONDAY MORNING LINGERING STORMS SHOULD BE EXITING OUR
SOUTHEAST CWA. HOWEVER WEAK IMPULSE IN MID LEVEL FLOW COULD TAP
WANING INSTABILITY IN THE MID AFTERNOON TO PRODUCE A STORM OR TWO
IN SOUTHWEST IOWA. THEN NORTHERLY SURFACE FLOW UNDER HIGH PRESSURE
WILL FORETELL A RELATIVELY DRY PERIOD OVER THE NEXT COUPLE OF
DAYS.
HIGHS BOTH TUESDAY AND WEDNESDAY WILL GRADUALLY INCREASE INTO THE
LOWER AND MIDDLE 80S UNDER PLENTY OF SUNSHINE. AND DEW POINTS SHOULD
BE LOWER ON TUESDAY BEFORE BEGINNING TO RETURN WEDNESDAY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 333 PM CDT SUN AUG 9 2015
OUR RELATIVELY QUIET WEATHER PATTERN IS EXPECTED TO CONTINUE THROUGH
THE REST OF THE WEEK. MID LEVEL HIGH PRESSURE RIDGE IS FORECAST BY
BOTH ECMWF AND GFS TO BUILD FROM THE SOUTHERN PLAINS INTO THE
NORTHERN ROCKIES...AND EXPAND A BIT TO THE EAST. THIS WILL TAKE MAIN
STORM TRACK NORTH AND EAST OF OUR AREA...AND ALLOW FOR WARMER
TEMPERATURES BOTH AT THE SURFACE AND ALOFT. WILL MAINTAIN OUR DRY
FORECAST UNTIL MAYBE SATURDAY NIGHT OR SUNDAY WHEN RIDGE IS FORECAST
TO BEGIN TO BREAK DOWN. HIGHS MAINLY IN THE UPPER 80S AND LOWER 90S
SHOULD PREVAIL.
&&
.AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1246 PM CDT SUN AUG 9 2015
ALL THREE TAF SITES HAVE IMPROVED TO MVFR WITH REGARD TO CEILINGS
AND VISIBILITY. THIS IMPROVEMENT TREND WILL CONTINUE THROUGH THE
EARLY HOURS OF THIS FORECAST CYCLE WITH MVFR BKN/OVC CIGS BECOMING
SCT. A COLD FRONT WILL APPROACH NORTHEAST NEBRASKA AFTER 00Z WHICH
WILL BRING THE NEXT ROUND OF THUNDERSTORMS. HAVE THUNDER IN ALL
THREE TAF SITES AFTER 03Z...STARTING THE EARLIEST AT KOFK. SOME
QUESTION AS TO TIMING SO WILL ADJUST AS NEEDED ONCE CONVECTION
INITIATES. THUNDERSTORMS SHOULD BE CLEAR OF THE FORECAST AREA
AFTER 12Z BUT HAVE LINGERING MVFR CIGS BEHIND THE COLD FRONT.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...DERGAN
LONG TERM...DERGAN
AVIATION...MEYER
AREA FORECAST DISCUSSION
NWS ELKO NV
318 PM PDT SUN AUG 9 2015
.SYNOPSIS...TEMPERATURES RUNNING SLIGHTLY BELOW NORMAL FOR THIS
TIME OF YEAR. ISOLATED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE
ACROSS NORTHERN NEVADA THIS AFTERNOON. THERE IS A CHANCE FOR
MONSOON MOISTURE MIDWEEK...FOLLOWED BY ANOTHER PACIFIC STORM NEXT
WEEKEND.
&&
.SHORT TERM...TODAY THROUGH TUESDAY. THE HRRR IS PRETTY CONVECTIVE
NORTH OF INTERSTATE 80 THIS AFTERNOON AND INTO THE EVENING...WHICH
GAINS SOME SUPPORT FROM THE LATEST VISIBLE IMAGE ON SATELLITE.
HOWEVER...WITH REGARD TO QPF...THE NAM AND THE HRRR MAY BE OVER
DOING IT A BIT...ALTHOUGH THE PLACEMENT OF THE CONVECTION IS
VERY FEASIBLE. LIGHTNING STRIKES HAVE BEEN OBSERVED OVER PORTIONS
OF ELKO COUNTY NEAR THE IDAHO BORDER. THE HRRR HAS THE CONVECTION
BASICALLY BEING SHUNTED AT 2Z...AND BY 5Z THE LKN CWA IS TSRA
FREE. TOMORROW THE GFS BRINGS A SLUG OF MOISTURE BY 18Z AND THE
NAM HAS NOTHING AT 18Z...AND A FRACTION OF THE QPF SHIELD BY 00Z
WITH AN OFF SET PLACEMENT. THE POPS IN THIS FORECAST PACKAGE
REPRESENTS A CONSALL MODEL BLEND APPROACH...BUT NOT THE BEST
CONFIDENCE. TUESDAY...MORE OF THE SAME CONSALL BLENDING...WITH THE
QPF ON THE EASTERN PORTION OF THE CWA...WHICH ACCOUNTS FOR THE
PROGRESSIVE NATURE OF THE INCOMING PACIFIC LOW.
.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY. A NORTHEAST PACIFIC LOW
MOVES ASHORE AND STRUGGLES TO ENTER THE INTERIOR WEST AS IT MOVES
AGAINST THE FOUR CORNERS RIDGE. THIS CREATES MOSTLY DRY FLOW INTO
THE GREAT BASIN...BUT AT TIMES WEAKNESSES IN THE RIDGE-TROUGH
BOUNDARY WILL ALLOW FOR LIMITED MOISTURE INTO THE REGION.
HENCE...PERIODS OF ISOLATED THUNDERSTORMS OF THE HYBRID VARIETY
THROUGH ABOUT FRIDAY. NEXT WEEKEND LOOKS DRY. TEMPS NEAR NORMAL. ONE
THING THOUGH...WINDS INCREASE WEDNESDAY AND THURSDAY WITH LOWER RH
VALUES FOR A POSSIBLE FIRE WEATHER SITUATION. STAY TUNED FOR WHEN
THIS TIME COMES INTO THE SHORT TERM PERIOD.
&&
.AVIATION...VFR CONDITIONS ARE EXPECTED AT KWMC KEKO KELY AND KTPH
THROUGH MONDAY AFTERNOON. ISOLATED THUNDERSTORMS ARE POSSIBLE OVER
NORTHERN NEVADA EARLY SUNDAY EVENING AND MONDAY AFTERNOON. MOST WILL
STAY CLEAR OF KWMC AND KEKO.
&&
.FIRE WEATHER...VIRGA...ISOLATED SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE ACROSS NORTHERN NEVADA THIS AFTERNOON. SO FAR FWZ 470...HAS
GOTTEN THE LIONS SHARE OF THE LIGHTNING AS CONVECTION HAS BEGUN
TO PERCOLATE OVER NORTHERN NV. THERE IS A CHANCE FOR MONSOON
MOISTURE MIDWEEK...FOLLOWED BY A WIND EVENT THURSDAY AND FRIDAY.
THE MODELS ARE FLIPPING A BIT AND NOT HANDLING THE MONSOON SURGE
FOLLOWED BY A ANOTHER PACNW STORM WELL. THIS ASSESSMENT IS BACKED
BY THE NCEP RMOP WHICH IS IN MARKEDLY LESS CONFIDENT TERRITORY BY
F72...WITH REGARD TO THE ENSEMBLE MEAN FORECAST AT 500 MB.
&&
.LKN WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
97/98/98/97
AREA FORECAST DISCUSSION
NWS RALEIGH NC
215 PM EDT SUN AUG 9 2015
.SYNOPSIS...WEAK HIGH PRESSURE WILL EXTEND INTO THE REGION THROUGH
TONIGHT. A WARM FRONT WILL LIFT NORTH ACROSS THE AREA ON MONDAY. A
COLD FRONT WILL SWEEP THROUGH THE REGION TUESDAY AND TUESDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 945 AM SUNDAY...
BAND OF LIGHT SHOWERS ORIENTED NNW TO SSE WHICH DROPPED SSE THROUGH
THE NRN PIEDMONT EARLIER THIS MORNING HAS PUSHED INTO THE SANDHILLS
WHILE DIMINISHING IN COVERAGE. THE SUBTLE FORCING DRIVING THIS
FEATURE INCLUDING WEAK LOW LEVEL MASS CONVERGENCE ALONG THE LEADING
EDGE OF AN 850 MB MOISTURE BOUNDARY APPEARS TO BE DWINDLING... AND
WITH THE DEPARTURE OF A WEAKENING MID LEVEL WAVE/MCV BY AFTERNOON...
THIS SHOULD CONTINUE TO FALL APART SLOWLY. MODELS SHOW MOUNTAIN
CONVECTION FORMING THIS AFTERNOON... AND THE MEAN FLOW PATTERN WOULD
SUPPORT SOME OF THIS ACTIVITY SLIPPING SE INTO THE FAR WRN PIEDMONT
AFTER SUNSET... SO WILL RETAIN LOW CHANCE POPS LATER TONIGHT. PATCHY
MOISTURE IS EXPECTED TO PERSIST AT 700 MB WITH WEAK FLOW... SO
EXPECT GENERALLY PARTLY CLOUDY SKIES AREAWIDE TODAY ESPECIALLY AS WE
APPROACH PEAK MIXING... WITH SHORTER PERIODS OF MOSTLY CLOUDY SKIES.
OBSERVED TRENDS AND HI-RES GUIDANCE SUPPORT HIGHS OF 85-90...
ASSUMING ENOUGH BREAKS IN THE CLOUDS FOR SUFFICIENT INSOLATION. -GIH
EARLIER DISCUSSION FROM 250 AM: LATEST SURFACE ANALYSIS SHOWS WEAK
HIGH PRESSURE CENTERED OVER THE MID ATLANTIC REGION AS LOW PRESSURE
OFF THE VA COAST MOVES AWAY FROM THE REGION. SATELLITE IMAGERY SHOWS
A REGION OF SCT TO MOSTLY BKN LOW/MID CLOUDS FROM CENTRAL PA
SOUTHWARD TO WESTERN NC. THESE CLOUDS HAVE BEEN EXPANDING SOUTHWARD
AND ARE ASSOCIATED WITH A REGION OF ENHANCED MOISTURE AND WEAK
ISENTROPIC UPGLIDE ABOUT THE 305K SURFACE. REGIONAL RADAR SHOWS A
FEW SHOWERS JUST NORTH OF THE TRIAD IN FAR NORTHERN NC AND
SOUTHWESTERN VA. EARLIER RUNS OF THE HRRR INDICATED THESE SHOWERS
COULD PUSH SOUTHEAST TOWARD THE TRIANGLE AREA BUT THE LAST RUN OR
TWO HAVE BACKED OFF THIS SCENARIO. WILL INCLUDE A SLIGHT CHANCE OF A
SHOWER FOR A SMALL AREA IN THE TRIAD FOR THE NEXT FEW HOURS AS THESE
SPRINKLES/SHOWERS MOVE SOUTHEAST AND LIKELY DISSIPATE.
THE REMAINDER OF TODAY SHOULD FEATURE FAIR WEATHER WITH PARTLY
CLOUDY SKIES FEATURING MULTIPLE CLOUD LAYERS. LITTLE FORCING FOR
ASCENT AND PRECIPITATION IS AVAILABLE ACROSS CENTRAL NC. ISOLATED TO
SCATTERED THUNDERSTORMS WILL DEVELOP ACROSS THE NC MOUNTAINS THIS
AFTERNOON. A FEW OF THESE STORMS COULD PUSH OFF THE MOUNTAINS AND
APPROACH THE TRIAD AREA TOWARD DINNER TIME BUT GIVEN THE LIMITED
COVERAGE AND STABLE AIRMASS ACROSS THE TRIAD...WILL NOT INCLUDE ANY
STORMS FOR THIS AFTERNOON OR EARLY EVENING. SCT CONVECTION THAT
DEVELOPS FURTHER UPSTREAM ACROSS THE OH VALLEY AND THE MID ATLANTIC
THIS AFTERNOON MAY HAVE SUFFICIENT SUPPORT TO ALLOW A SHOWER OR
STORM MOVE INTO THE NORTHWEST PIEDMONT VERY LATE IN THE EVENING.
THIS SCENARIO IS SUPPORTED BY A FEW OF THE CONVECTION ALLOWING
MODELS INCLUDING THE NCAR ENSEMBLE. SO WILL INCLUDE A SLIGHT CHC POP
FOR THIS AREA TO COVER THE POTENTIAL. OTHERWISE...FAIR WEATHER AND
DRY CONDITIONS ARE EXPECTED TODAY AND TONIGHT. THICKNESSES VALUES
AND STATISTICAL GUIDANCE HAVE TRENDED A LITTLE COOLER FOR TODAYS
HIGHS WHICH SHOULD RANGE BETWEEN 86 AND 90. LOWS TONIGHT WILL RANGE
BETWEEN 66-72. LIGHT AND VARIABLE WINDS WILL BECOME LIGHT
SOUTHEASTERLY AND SOUTHERLY ACROSS THE WESTERN PIEDMONT TODAY AND
BECOME LIGHT NORTHEAST AND EASTERLY EAST OF THE RIDGE AXIS ACROSS
THE EASTERN PIEDMONT AND COASTAL PLAIN. -BLAES
&&
.SHORT TERM /MONDAY AND MONDAY NIGHT/...
AS OF 312 AM SUNDAY...
A NORTHWEST FLOW ALOFT ACROSS CENTRAL NC EARLY MONDAY BECOMES MORE
WESTERLY AND SLIGHTLY SOUTHWESTERLY BY MONDAY NIGHT AS UPPER LEVEL
TROUGHING AND THE ASSOCIATED HEIGHT FALLS MOVE INTO THE GREAT LAKES
REGION. AT THE SURFACE...A WARM FRONT WILL LIFT NORTH ACROSS NC
EARLY MONDAY WITH AN APPROACHING COLD FRONT REACHING THE WESTERN
APPALACHIANS TOWARD DAYBREAK TUESDAY. CHANCES FOR SHOWERS AND
THUNDERSTORMS GRADUALLY INCREASE DURING THE PERIOD FROM WEST TO
EAST. WITH THE BEST FORCING REMAINING NORTH OF OUR REGION AND
INDICATIONS OF LIMITED INSTABILITY AND MEAGER MID LEVEL LAPSE
RATES...HAVE CUT BACK ON POPS A BIT. NEW SPC DAY 2 OUTLOOK KEEPS THE
MARGINAL SEVERE WEATHER THREAT WEST OF OUR AREA...MAINLY OWING TO
THE LIMITED INSTABILITY IN OUR FORECAST AREA. DESPITE A WARMING
ATMOSPHERE AND INCREASING THICKNESS VALUES...CLOUDS SHOULD HOLD
HIGHS BACK SLIGHTLY ON MONDAY...HIGH SHOULD RANGE BETWEEN 86 AND 92.
LOWS MONDAY NIGHT WILL BE MODERATED BY THE CLOUD COVER AND RANGE
BETWEEN 69 AND 74 DEGREES. -BLAES
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
AS OF 200 PM SUNDAY...
TUESDAY AND WEDNESDAY: MODELS ARE COMING INTO FAIRLY GOOD AGREEMENT
AS FAR AS THE SYNOPTIC PATTERN IS CONCERNED FOR TUESDAY.
ALOFT...EXPECT AN EASTERN CONUS TROUGH WITH A STRONG RIDGE OVER THE
MOUNTAIN WEST. WHILE THE TROUGH IS EXPECTED TO DEEPEN OVER THE
CAROLINAS ON TUESDAY...IT IS NOT EXPECTED TO TRANSLATE MUCH TO THE
EAST AND THUS CENTRAL NC WILL REMAIN NEAR THE BASE OF THIS TROUGH
WITH RELATIVELY WEAK WINDS ALOFT. AT THE SURFACE...LOW PRESSURE OVER
NEW YORK STATE WILL HELP MOVE A COLD FRONT THROUGH THE APPALACHIANS
AND INTO THE CAROLINAS ON TUESDAY AFTERNOON...EXITING TUESDAY NIGHT
INTO WEDNESDAY MORNING.
ONGOING PREFRONTAL CONVECTIVE ACTIVITY ON TUESDAY MORNING MAY PLAY A
KEY ROLE IN LIMITING DESTABILIZATION OVER THE AREA AND FORECAST
SOUNDINGS CERTAINLY INDICATE THIS WITH BOTH THE GFS AND THE NAM
SHOWING MAX INSTABILITY NEAR 1000 J/KG AS OPPOSED TO THE 1500-2000
J/KG SHOWN IN PRIOR SIMULATIONS. BULK SHEAR HAS ALSO COME DOWN BUT
STILL SHOULD REMAIN AROUND 20-25 KTS. THIS COULD SUPPORT SOME
MULTICELLULAR TO BROKEN LINE SEGMENT ACTIVITY AS THE FRONT MOVES
THROUGH LATER IN THE DAY ON TUESDAY. THEREFORE EXPECT STRONG STORMS
WITH A FEW ISOLATED SEVERE THUNDERSTORMS POSSIBLE WITH DAMAGING
WINDS THE MOST LIKELY THREAT. CURRENTLY THE SPC DAY 3 CONVECTIVE
OUTLOOK HAS THE AREA UNDER A MARGINAL RISK FOR SEVERE STORMS ON
TUESDAY. WITH PRE-FRONTAL CLOUD COVER EXPECT HIGHS IN THE UPPER 80S
TO LOW 90S WITH LOWS TUESDAY NIGHT IN THE UPPER 60S TO LOWER 70S.
WEDNESDAY THROUGH SUNDAY:
THE FRONT WILL EXIT TO THE EAST ON WEDNESDAY ALTHOUGH SOME LINGERING
SHOWERS COULD STILL THREATEN THE EXTREME SOUTHEASTERN
COUNTIES...PARTICULARLY WEDNESDAY AFTERNOON ON A SEABREEZE.
OTHERWISE HIGH PRESSURE OVER THE OHIO VALLEY WILL BUILD INTO THE
AREA FROM THE NORTHWEST...YIELDING COOL NORTHERLY FLOW AND DRY
CONDITIONS. HIGH WILL BUILD IN OVER THE CAROLINAS FOR THE END OF THE
WEEK AND INTO THE WEEKEND AS UPPER LEVEL FLOW BECOMES VERY STAGNANT.
THIS WILL LEAD TO A PROLONGED PERIOD OF QUIET WEATHER AND RELATIVELY
COOLER TEMPERATURES. HIGH TEMPERATURES GENERALLY IN THE MID TO UPPER
80S WITH LOWS IN THE LOW TO UPPER 60S.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 215 PM SUNDAY...
VFR CONDITIONS EXPECTED TO DOMINATE THROUGH TONIGHT... ALTHOUGH
THERE IS A CHANCE OF MVFR CONDITIONS TONIGHT INTO MON MORNING AT
INT/GSO AFTER 08Z. WEAK HIGH PRESSURE SITS ACROSS CENTRAL NC THIS
AFTERNOON... AND THIS WILL GIVE WAY TO A WARM FRONT MOVING FROM OUR
SW TO THE NE THROUGH NC LATE TONIGHT THROUGH MON... RESULTING IN THE
CURRENT LIGHT/VARIABLE SURFACE WINDS TO INCREASE TO 7-12 KTS MON
MORNING FROM THE S/SW. WE`LL CONTINUE TO SEE TYPICAL DAYTIME CLOUDS
WITH VFR CIGS INTO EARLY THIS EVENING... FOLLOWED BY INCREASING AND
THICKENING MID AND HIGH CLOUDS (ALSO VFR) DURING THE EVENING AND
CONTINUING OVERNIGHT AS THE REMNANT CLOUDINESS LEFTOVER FROM
UPSTREAM STORM COMPLEXES DRIFT SOUTHEASTWARD OVER OUR REGION.
ISOLATED SHOWERS ARE POSSIBLE TONIGHT NEAR INT/GSO AND PERHAPS
REACHING RDU LATE TONIGHT. DESPITE THIS... VSBYS/CIGS SHOULD STAY
PREDOMINANTLY VFR... ALTHOUGH THERE IS A SMALL CHANCE THAT CIGS
COULD DROP TO HIGH-END MVFR AFTER 08Z TONIGHT AT INT/GSO... AND
AVIATION INTERESTS SHOULD CHECK BACK FOR LATER FORECASTS. SCATTERED
STORMS ARE EXPECTED TO DEVELOP NEAR THE END OF THE TAF VALID PERIOD.
LOOKING BEYOND 18Z MON: SCATTERED TO NUMEROUS SHOWERS AND STORMS ARE
EXPECTED MON AFTERNOON... AFFECTING INT/GSO FIRST THEN REACHING RDU
AND FINALLY RWI/FAY BY LATE AFTERNOON... AND STRONG ERRATIC GUSTY
WINDS ALONG WITH SUB-VFR CONDITIONS CAN BE EXPECTED IN AND NEAR ANY
SUCH STORMS. STORMS WILL DECREASE IN INTENSITY MON EVENING/NIGHT BUT
CHANCES REMAIN HIGH FOR SUB-VFR VSBYS/CIGS IN RAIN/ISOLD THUNDER
THROUGH MON NIGHT. ANOTHER ROUND OF AFTERNOON STORMS IS EXPECTED TUE
AS A COLD FRONT MOVES THROUGH THE AREA. MAINLY VFR CONDITIONS
EXPECTED WED-FRI AS HIGH PRESSURE BUILDS IN FROM THE NW. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLAES
NEAR TERM...HARTFIELD/BLAES
SHORT TERM...BLAES
LONG TERM...ELLIS
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
153 PM EDT SUN AUG 9 2015
.SYNOPSIS...WEAK HIGH PRESSURE WILL EXTEND INTO THE REGION THROUGH
TONIGHT. A WARM FRONT WILL LIFT NORTH ACROSS THE AREA ON MONDAY. A
COLD FRONT WILL SWEEP THROUGH THE REGION TUESDAY AND TUESDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 945 AM SUNDAY...
BAND OF LIGHT SHOWERS ORIENTED NNW TO SSE WHICH DROPPED SSE THROUGH
THE NRN PIEDMONT EARLIER THIS MORNING HAS PUSHED INTO THE SANDHILLS
WHILE DIMINISHING IN COVERAGE. THE SUBTLE FORCING DRIVING THIS
FEATURE INCLUDING WEAK LOW LEVEL MASS CONVERGENCE ALONG THE LEADING
EDGE OF AN 850 MB MOISTURE BOUNDARY APPEARS TO BE DWINDLING... AND
WITH THE DEPARTURE OF A WEAKENING MID LEVEL WAVE/MCV BY AFTERNOON...
THIS SHOULD CONTINUE TO FALL APART SLOWLY. MODELS SHOW MOUNTAIN
CONVECTION FORMING THIS AFTERNOON... AND THE MEAN FLOW PATTERN WOULD
SUPPORT SOME OF THIS ACTIVITY SLIPPING SE INTO THE FAR WRN PIEDMONT
AFTER SUNSET... SO WILL RETAIN LOW CHANCE POPS LATER TONIGHT. PATCHY
MOISTURE IS EXPECTED TO PERSIST AT 700 MB WITH WEAK FLOW... SO
EXPECT GENERALLY PARTLY CLOUDY SKIES AREAWIDE TODAY ESPECIALLY AS WE
APPROACH PEAK MIXING... WITH SHORTER PERIODS OF MOSTLY CLOUDY SKIES.
OBSERVED TRENDS AND HI-RES GUIDANCE SUPPORT HIGHS OF 85-90...
ASSUMING ENOUGH BREAKS IN THE CLOUDS FOR SUFFICIENT INSOLATION. -GIH
EARLIER DISCUSSION FROM 250 AM: LATEST SURFACE ANALYSIS SHOWS WEAK
HIGH PRESSURE CENTERED OVER THE MID ATLANTIC REGION AS LOW PRESSURE
OFF THE VA COAST MOVES AWAY FROM THE REGION. SATELLITE IMAGERY SHOWS
A REGION OF SCT TO MOSTLY BKN LOW/MID CLOUDS FROM CENTRAL PA
SOUTHWARD TO WESTERN NC. THESE CLOUDS HAVE BEEN EXPANDING SOUTHWARD
AND ARE ASSOCIATED WITH A REGION OF ENHANCED MOISTURE AND WEAK
ISENTROPIC UPGLIDE ABOUT THE 305K SURFACE. REGIONAL RADAR SHOWS A
FEW SHOWERS JUST NORTH OF THE TRIAD IN FAR NORTHERN NC AND
SOUTHWESTERN VA. EARLIER RUNS OF THE HRRR INDICATED THESE SHOWERS
COULD PUSH SOUTHEAST TOWARD THE TRIANGLE AREA BUT THE LAST RUN OR
TWO HAVE BACKED OFF THIS SCENARIO. WILL INCLUDE A SLIGHT CHANCE OF A
SHOWER FOR A SMALL AREA IN THE TRIAD FOR THE NEXT FEW HOURS AS THESE
SPRINKLES/SHOWERS MOVE SOUTHEAST AND LIKELY DISSIPATE.
THE REMAINDER OF TODAY SHOULD FEATURE FAIR WEATHER WITH PARTLY
CLOUDY SKIES FEATURING MULTIPLE CLOUD LAYERS. LITTLE FORCING FOR
ASCENT AND PRECIPITATION IS AVAILABLE ACROSS CENTRAL NC. ISOLATED TO
SCATTERED THUNDERSTORMS WILL DEVELOP ACROSS THE NC MOUNTAINS THIS
AFTERNOON. A FEW OF THESE STORMS COULD PUSH OFF THE MOUNTAINS AND
APPROACH THE TRIAD AREA TOWARD DINNER TIME BUT GIVEN THE LIMITED
COVERAGE AND STABLE AIRMASS ACROSS THE TRIAD...WILL NOT INCLUDE ANY
STORMS FOR THIS AFTERNOON OR EARLY EVENING. SCT CONVECTION THAT
DEVELOPS FURTHER UPSTREAM ACROSS THE OH VALLEY AND THE MID ATLANTIC
THIS AFTERNOON MAY HAVE SUFFICIENT SUPPORT TO ALLOW A SHOWER OR
STORM MOVE INTO THE NORTHWEST PIEDMONT VERY LATE IN THE EVENING.
THIS SCENARIO IS SUPPORTED BY A FEW OF THE CONVECTION ALLOWING
MODELS INCLUDING THE NCAR ENSEMBLE. SO WILL INCLUDE A SLIGHT CHC POP
FOR THIS AREA TO COVER THE POTENTIAL. OTHERWISE...FAIR WEATHER AND
DRY CONDITIONS ARE EXPECTED TODAY AND TONIGHT. THICKNESSES VALUES
AND STATISTICAL GUIDANCE HAVE TRENDED A LITTLE COOLER FOR TODAYS
HIGHS WHICH SHOULD RANGE BETWEEN 86 AND 90. LOWS TONIGHT WILL RANGE
BETWEEN 66-72. LIGHT AND VARIABLE WINDS WILL BECOME LIGHT
SOUTHEASTERLY AND SOUTHERLY ACROSS THE WESTERN PIEDMONT TODAY AND
BECOME LIGHT NORTHEAST AND EASTERLY EAST OF THE RIDGE AXIS ACROSS
THE EASTERN PIEDMONT AND COASTAL PLAIN. -BLAES
&&
.SHORT TERM /MONDAY AND MONDAY NIGHT/...
AS OF 312 AM SUNDAY...
A NORTHWEST FLOW ALOFT ACROSS CENTRAL NC EARLY MONDAY BECOMES MORE
WESTERLY AND SLIGHTLY SOUTHWESTERLY BY MONDAY NIGHT AS UPPER LEVEL
TROUGHING AND THE ASSOCIATED HEIGHT FALLS MOVE INTO THE GREAT LAKES
REGION. AT THE SURFACE...A WARM FRONT WILL LIFT NORTH ACROSS NC
EARLY MONDAY WITH AN APPROACHING COLD FRONT REACHING THE WESTERN
APPALACHIANS TOWARD DAYBREAK TUESDAY. CHANCES FOR SHOWERS AND
THUNDERSTORMS GRADUALLY INCREASE DURING THE PERIOD FROM WEST TO
EAST. WITH THE BEST FORCING REMAINING NORTH OF OUR REGION AND
INDICATIONS OF LIMITED INSTABILITY AND MEAGER MID LEVEL LAPSE
RATES...HAVE CUT BACK ON POPS A BIT. NEW SPC DAY 2 OUTLOOK KEEPS THE
MARGINAL SEVERE WEATHER THREAT WEST OF OUR AREA...MAINLY OWING TO
THE LIMITED INSTABILITY IN OUR FORECAST AREA. DESPITE A WARMING
ATMOSPHERE AND INCREASING THICKNESS VALUES...CLOUDS SHOULD HOLD
HIGHS BACK SLIGHTLY ON MONDAY...HIGH SHOULD RANGE BETWEEN 86 AND 92.
LOWS MONDAY NIGHT WILL BE MODERATED BY THE CLOUD COVER AND RANGE
BETWEEN 69 AND 74 DEGREES. -BLAES
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
AS OF 200 PM SUNDAY...
TUESDAY AND WEDNESDAY: MODELS ARE COMING INTO FAIRLY GOOD AGREEMENT
AS FAR AS THE SYNOPTIC PATTERN IS CONCERNED FOR TUESDAY.
ALOFT...EXPECT AN EASTERN CONUS TROUGH WITH A STRONG RIDGE OVER THE
MOUNTAIN WEST. WHILE THE TROUGH IS EXPECTED TO DEEPEN OVER THE
CAROLINAS ON TUESDAY...IT IS NOT EXPECTED TO TRANSLATE MUCH TO THE
EAST AND THUS CENTRAL NC WILL REMAIN NEAR THE BASE OF THIS TROUGH
WITH RELATIVELY WEAK WINDS ALOFT. AT THE SURFACE...LOW PRESSURE OVER
NEW YORK STATE WILL HELP MOVE A COLD FRONT THROUGH THE APPALACHIANS
AND INTO THE CAROLINAS ON TUESDAY AFTERNOON...EXITING TUESDAY NIGHT
INTO WEDNESDAY MORNING.
ONGOING PREFRONTAL CONVECTIVE ACTIVITY ON TUESDAY MORNING MAY PLAY A
KEY ROLE IN LIMITING DESTABILIZATION OVER THE AREA AND FORECAST
SOUNDINGS CERTAINLY INDICATE THIS WITH BOTH THE GFS AND THE NAM
SHOWING MAX INSTABILITY NEAR 1000 J/KG AS OPPOSED TO THE 1500-2000
J/KG SHOWN IN PRIOR SIMULATIONS. BULK SHEAR HAS ALSO COME DOWN BUT
STILL SHOULD REMAIN AROUND 20-25 KTS. THIS COULD SUPPORT SOME
MULTICELLULAR TO BROKEN LINE SEGMENT ACTIVITY AS THE FRONT MOVES
THROUGH LATER IN THE DAY ON TUESDAY. THEREFORE EXPECT STRONG STORMS
WITH A FEW ISOLATED SEVERE THUNDERSTORMS POSSIBLE WITH DAMAGING
WINDS THE MOST LIKELY THREAT. CURRENTLY THE SPC DAY 3 CONVECTIVE
OUTLOOK HAS THE AREA UNDER A MARGINAL RISK FOR SEVERE STORMS ON
TUESDAY. WITH PRE-FRONTAL CLOUD COVER EXPECT HIGHS IN THE UPPER 80S
TO LOW 90S WITH LOWS TUESDAY NIGHT IN THE UPPER 60S TO LOWER 70S.
WEDNESDAY THROUGH SUNDAY:
THE FRONT WILL EXIT TO THE EAST ON WEDNESDAY ALTHOUGH SOME LINGERING
SHOWERS COULD STILL THREATEN THE EXTREME SOUTHEASTERN
COUNTIES...PARTICULARLY WEDNESDAY AFTERNOON ON A SEABREEZE.
OTHERWISE HIGH PRESSURE OVER THE OHIO VALLEY WILL BUILD INTO THE
AREA FROM THE NORTHWEST...YIELDING COOL NORTHERLY FLOW AND DRY
CONDITIONS. HIGH WILL BUILD IN OVER THE CAROLINAS FOR THE END OF THE
WEEK AND INTO THE WEEKEND AS UPPER LEVEL FLOW BECOMES VERY STAGNANT.
THIS WILL LEAD TO A PROLONGED PERIOD OF QUIET WEATHER AND RELATIVELY
COOLER TEMPERATURES. HIGH TEMPERATURES GENERALLY IN THE MID TO UPPER
80S WITH LOWS IN THE LOW TO UPPER 60S.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AS OF 705 AM SUNDAY...
VFR CONDITIONS ARE EXPECTED TO DOMINATE ACROSS CENTRAL NC DURING THE
NEXT 24 HOURS. AN UPPER LEVEL DISTURBANCE WAS PRODUCING AN AREA OF
SCT-BKN CLOUDS WITH VFR BASES OF 6-8KFT ACROSS THE PIEDMONT
AREA THIS MORNING. THESE CLOUDS WILL CONTINUE TO IMPACT THE
TERMINALS AT KINT/KGSO/KRDU THROUGH MID MORNING. RADAR AND SURFACE
OBSERVATIONS WERE INDICATING A FEW SHOWERS BETWEEN THE TRIAD AND
TRIANGLE IMPACTING KBUY AND KSCR THAT WERE SHIFTING EAST. A LOWERING
OF THE CLOUD DECK AND A BRIEF MVFR VSBY RESTRICTION IN A LIGHT RAIN
SHOWER CAN BE EXPECTED. WILL OMIT ANY MENTION IN THE TAFS AS THIS
FEATURE SHOULD DIMINISH BY THE TIME IT WOULD APPROACH KRDU. A FEW
THUNDERSTORMS MAY DEVELOP ACROSS THE
BLUE RIDGE THIS AFTERNOON AND DRIFT INTO THE WESTERN PIEDMONT DURING
THE EARLY EVENING. COVERAGE OF THESE STORMS SHOULD BE LIMITED AND
CONFIDENCE THAT THEY WILL MAKE IT TO THE KINT/KGSO TERMINALS IS VERY
SMALL SO WILL NOT INCLUDE IT IN THE TERMINALS.
OTHERWISE...LOOK FOR MAINLY SCT TO OCCASIONALLY BKN CLOUDS AT 5-8KFT
TODAY WITH PERIODS OF BKN MID AND HIGH CLOUDS. LIGHT AND VARIABLE
WINDS THIS MORNING WILL BECOME LIGHT SOUTHWEST IN THE WESTERN
PIEDMONT (KINT/KGSO)AND LIGHT NORTHEASTERLY IN THE EASTERN PIEDMONT
AND COASTAL PLAIN TERMINALS (KRDU/KRWI/KFAY).
LOOKING FURTHER AHEAD... A TREND FOR MORE ACTIVE WEATHER AND
POTENTIAL ADVERSE AVIATION CONDITIONS WITH SCT CONVECTION RETURNS ON
MONDAY AND INCREASES FOR MONDAY NIGHT AND TUESDAY/TUESDAY NIGHT AS A
COLD FRONT MOVES THROUGH THE AREA. FAIR WEATHER SHOULD RETURN ON
WEDNESDAY AND PERSIST INTO THURSDAY. -BLAES
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLAES
NEAR TERM...HARTFIELD/BLAES
SHORT TERM...BLAES
LONG TERM...ELLIS
AVIATION...BLAES
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1156 AM CDT SUN AUG 9 2015
.UPDATE...
ISSUED AT 1126 AM CDT SUN AUG 9 2015
WATER VAPOR IMAGERY LOOP CONTINUES TO SHOW A MID/UPPER LEVEL LOW
CIRCULATING OVER SOUTHEAST MONTANA...WITH A LEAD SHORTWAVE SEEN
SCOOTING ALONG THE ND/SD BORDER...LOCATED CLOSE TO LEMMON SD.
LOCAL/REGIONAL RADAR DETAILS AN AREA AND A LINE OF SHOWERS/THUNDERSTORMS
ASSOCIATED WITH THIS SHORTWAVE...MOVING EAST BUT ALSO SLOWLY
DEVELOPING NORTH. SPC MESOANALYSIS OVER SOUTHERN NORTH DAKOTA
CERTAINLY INDICATING DESTABILIZING CONDITIONS WITH INCREASING SFC
BASED CAPE TO 1000 J/KG...AND LOW LEVEL LAPSE RATES TO 7-7.5 C/KM.
0-6KM SHEAR NUDGING NORTH ACROSS THE BORDER TO 25KT. MID LEVEL
LAPSE RATES REMAIN WEAK AT THIS TIME. AS THE UPPER LOW EDGES CLOSER
INTO NORTHWEST SOUTH DAKOTA THIS AFTERNOON SCATTERED SHOWERS/THUNDERSTORMS
WILL CONTINUE TO DEVELOP ACROSS SOUTHERN NORTH DAKOTA. NOT EXPECTING
SEVERE WEATHER AT THIS TIME...AS THE HIGHEST INSTABILITY PARAMETERS
WILL REMAIN IN SOUTH DAKOTA. FOR THIS UPDATE...MAIN MINOR CHANGES
TO HOURLY TEMPERATURES AND POPS BASED ON LATEST SATELLITE/SURFACE
OBSERVATIONS...ALONG WITH THE HRRR AND RADAR TRENDS.
UPDATE ISSUED AT 900 AM CDT SUN AUG 9 2015
LATEST WATER VAPOR WITH RAP13 UPPER HEIGHTS OVERLAID ACCURATELY
PORTRAY A MID/UPPER LOW CIRCULATION OVER SOUTHEAST MONTANA WITH A
COUPLE OF SHORTWAVES ROTATING AROUND THE LOW INTO SOUTHWEST NORTH
DAKOTA. BOWMAN RADAR CONTINUES TO SHOW INCREASING RAIN SHOWER
COVERAGE SOUTHWEST...WITH BISMARCK RADAR INDICATING ISOLATED TO
SCATTERED SHOWERS IN SOUTH CENTRAL NORTH DAKOTA AND INTO THE
SOUTHERN JAMES RIVER VALLEY. FOR THIS UPDATE...BLENDED IN CURRENT
FORECAST WITH THE LATEST HRRR AND ADJUSTED THOSE POPS BASED ON
CURRENT RADAR TRENDS AND SURFACE OBSERVATIONS.
OVERALL...MODEL CONSENSUS AND FORECAST OVERALL REMAINS NEARLY
UNCHANGED WITH ISOLATED TO SCATTERED SHOWERS MAINLY ALONG AND
SOUTH OF I-94 REST OF THIS MORNING. FOR THE AFTERNOON...SCATTERED
SHOWERS AND THUNDERSTORMS DEVELOPING A BIT FARTHER NORTH AS THE
MID/UPPER LOW SLIDES INTO NORTHWEST SOUTH DAKOTA.
UPDATE ISSUED AT 643 AM CDT SUN AUG 9 2015
LOWERED SHORT TERM POPS SLIGHTLY ACROSS THE SOUTHWEST BASED ON
LATEST RADAR IMAGERY. CURRENTLY SEEING A SLIGHT LULL IN SHOWERS
ACROSS SOUTHWEST. HOWEVER...WV IMAGERY SHOWS WEAK DISTURBANCE IN
CYCLONIC FLOW OVER SOUTHEASTERN MONTANA THAT IS APPROACHING OUR
CWA. IR IMAGERY SHOWS COOLER CLOUD TOPS APPROACHING OUR SOUTHWEST AND
LAST FEW SCANS FROM BOWMAN RADAR SHOW ECHOES DEVELOPING AGAIN OVER
THE SAME AREA. OTHERWISE...BLENDED OTHER FORECAST ELEMENTS TO
LATEST OBS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM CDT SUN AUG 9 2015
THE MAIN FOCUS TODAY IS ON SHOWERS AND THUNDERSTORMS ALONG AND
SOUTH OF U.S. HIGHWAY 2.
SO FAR THIS MORNING...THE 00 UTC NAM ARW/NAM NMM AND THE LAST FEW
RUNS OF THE HRRR HAVE A GOOD HANDLE ON SHOWERS INITIATING IN
SOUTHWEST AND SOUTH CENTRAL NORTH DAKOTA AS ONGOING CONVECTION
SHIFTS INTO NORTHEASTERN SOUTH DAKOTA.
THUS FAR...THUNDERSTORMS HAVE BEEN CONFINED TO SOUTH DAKOTA...BUT
THAT SHOULD CHANGE AROUND NOON AS SOLAR HEATING HELPS
DESTABILIZATION BENEATH THE MID LEVEL LOW OVER EASTERN MONTANA IN
08 UTC WATER VAPOR IMAGERY. BASED ON HIRES MODELS...AND VALIDATED
BY THE STORM PREDICTION CENTER CONVECTIVE OUTLOOKS...THE SEVERE
THREAT IS LOW.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 334 AM CDT SUN AUG 9 2015
MODELS ARE IN GOOD AGREEMENT BUILDING STRONG UPPER LEVEL RIDGE
ACROSS THE WEST EARLY IN THE WEEK WITH THE RIDGE AXIS SLOWLY
MOVING EAST. DRY WEATHER EXPECTED THROUGH MOST OF THE WEEK WITH
TEMPERATURES BUILDING TO MUCH ABOVE NORMAL BY MID-WEEK...UPPER
90S POSSIBLE WEST BY WEDNESDAY. SOME MODEL DIFFERENCES DEVELOP BY
LATE WEEK AS STRONG UPPER LEVEL LOW MOVES INTO THE PAC NW WITH THE
UPPER LEVEL RIDGE AXIS SHIFTING EAST OF THE NORTHERN PLAINS BY
EARLY WEEKEND. MAX TEMPS MODERATE BY LATE WEEK...STILL ABOVE
NORMAL IN THE UPPER 80S...WITH INCREASING CHANCES OF
SHOWERS/THUNDERSTORMS INTO THE WEEKEND AS UPPER LEVEL RIDGE BREAKS
DOWN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1126 AM CDT SUN AUG 9 2015
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS CAN BE EXPECTED FROM
KDIK/KBIS/KJMS THROUGH 00Z MONDAY. DESPITE THE PRECIPITATION...VFR
CIGS/VSBYS REMAIN ON TRACK THROUGH THE TAF PERIOD. A MAINLY CLEAR
SKY WILL ENSUE SUNDAY NIGHT THROUGH MONDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...SCHECK
LONG TERM...JNS
AVIATION...KS
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
102 PM CDT SUN AUG 9 2015
.UPDATE...
ISSUED AT 1247 PM CDT SUN AUG 9 2015
STRATUS LIKELY HAVING AN AFFECT ON THE AREA SO FAR AND THIS IS
SEEN WITH THE LATEST HRRR OUTPUT. WHILE TEMPERATURES ARE IN THE
UPPER 70S TO NEAR 80 IN MOST LOCATIONS THE HRRR RAISES
TEMPERATURES INTO THE MID 80S ALONG HIGHWAY 14 BY 18Z WHICH SEEMS
UNLIKELY. THE HRRR REALLY CRANKS OUT STRONG TO SEVERE
THUNDERSTORMS IN THE NORTHERN CWA BETWEEN 18Z-21Z BECAUSE OF THIS
HEATING. SO THIS SEEMS VERY DOUBTFUL BUT THERE IS AN OUTFLOW ALONG
HIGHWAY 14 SO WILL KEEP AN EYE. ALSO OF CONCERN ARE THE VERY LOW
LFC LEVELS WHICH MIGHT SUPPORT BRIEF SPIN UPS AND POSSIBLE
TORNADOES IF A STRONG THUNDERSTORM CAN DEVELOP. AT THIS TIME THE
MOST LIKELY LOCATION FOR DEVELOPMENT STILL SEEMS LIKE ALONG AND
WEST OF THE JAMES RIVER VALLEY...ESPECIALLY SOUTH CENTRAL SD
NEAREST THE WEAK SURFACE LOW. LATEST ANALYSIS HAS ABOUT 40 KNOTS
OF DEEP LAYER SHEAR ACROSS THE AREA AND ABOUT 2000 J/KG CAPE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM CDT SUN AUG 9 2015
CONVECTION AND ASSOCIATED SEVERE THREAT ARE MAIN FOCUS FOR TODAY.
MORNING HOURS SHOULD BE RATHER BENIGN...WITH CHANCE FOR NON-SEVERE
ACTIVITY DRIFTING INTO OUR FAR WEST OUT OF CENTRAL SD. MAIN FOCUS
WILL BE ON WELL-DEFINED UPPER WAVE CURRENTLY IN CENTRAL MONTANA AS
IT MOVES INTO THE DAKOTAS. ASSOCIATED SURFACE LOW WILL MOVE INTO
SOUTH CENTRAL SD BY MIDDAY/EARLY AFTERNOON. EVENTUAL TRACK OF THE
LOW WILL LIKELY BE DRIVEN BY CONVECTION...BUT CURRENTLY LOOKS TO
TRACK EAST-SOUTHEAST THROUGH THE MISSOURI RIVER VALLEY THROUGH THE
AFTERNOON/EARLY EVENING. FORECAST SOUNDINGS SHOW MINIMAL CAP...SO
SHOULD NOT BE DIFFICULT TO GET STORMS GOING ACROSS OUR WEST BY THE
EARLY-MID AFTERNOON. WITH PROXIMITY TO SURFACE LOW AND ASSOCIATED
WARM FRONT...LOW LEVEL HELICITY SHOULD BE LOCALLY ENHANCED AND
PRESENT A RISK OF TORNADOES. THINK THIS WILL BE FOCUSED IN AREAS
WEST OF THE JAMES RIVER VALLEY DURING THE MID-LATE AFTERNOON.
PRIMARY QUESTION AT THIS POINT IS EXACTLY WHERE THE SURFACE LOW
AND ATTENDANT BOUNDARIES WILL BE LOCATED...AS MODELS VARY FROM
NORTH CENTRAL NEBRASKA TO NEAR I-90 CORRIDOR. HAVE LEANED TOWARD
THE MORE NORTHERN SOLUTION FOR NOW...BUT WILL HAVE TO BE MONITORED
THROUGH THE DAY.
ALONG WITH THREAT OF ISOLATED TORNADOES WILL COME POTENTIAL FOR
LARGE HAIL AND DAMAGING WINDS. HAIL THREAT IN PARTICULAR WILL
EXTEND FARTHER NORTH INTO THE DEEPER EASTERLY LOW LEVEL FLOW...AND
CONTINUE AS THE STORMS TRACK EAST-SOUTHEAST ACROSS THE REGION
THROUGH THE EVENING...WITH SEVERE THREAT WANING AFTER MIDNIGHT AS
THE STORMS CONTINUE EAST AND AIRMASS BECOMES LESS UNSTABLE. WITH
MODELS INDICATING PRECIPITABLE WATER VALUES NEAR 1.5-2 INCHES...
COULD ALSO SEE LOCALLY HEAVY RAIN. HOWEVER EXPECT STORMS TO BE
SOMEWHAT PROGRESSIVE SO FLASH FLOODING THREAT SHOULD BE MINIMIZED
OUTSIDE ISOLATED URBAN LOCATIONS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 408 AM CDT SUN AUG 9 2015
SHOWERS WILL EXIT THE SOUTHEAST PART OF THE AREA BY EARLY MONDAY
AFTERNOON AS THE DRY AIR PUSHES IN BEHIND THE COLD FRONT. THIS LEADS
INTO AN OTHERWISE DRY MONDAY THROUGH FRIDAY PERIOD AS THE DIGGING
TROUGH TO THE EAST AND THE PERSISTENT MONSTER RIDGE TO THE SOUTHWEST
PRODUCE A DRY FLOW. AS THIS RIDGE BUILDS SLOWLY TOWARD THE AREA
DURING THE WEEK...TEMPERATURES WILL WARM GRADUALLY FROM NEAR TO JUST
BELOW NORMAL TO ABOVE NORMAL...BUT THE WARMING PATTERN WILL BE
UNFAVORABLE TO PROVIDE THERMAL LIFT FOR STORMS...WHICH MAY BE MOOT
SINCE THE SLOWNESS OF ANY MOISTURE INCREASE IN THIS PATTERN WILL
ALSO PUT THE CLAMPS ON ANY STORM THREAT.
BY SATURDAY THE APPROACH OF A FRONT AND UPPER WAVE FROM THE
WEST/NORTHWEST MAY ALLOW A THREAT OF STORMS TO BEGIN FROM THAT
SIDE OF THE AREA.
THE GRADUAL NATURE OF THE RIDGE BUILDING AND WARMING SHOULD KEEP THE
WARMING TO NO WORSE THAN THE UPPER 80S TO LOW 90S FOR HIGHS BY THE
END OF THE WEEK. SHOULD THE RIDGE BUILD IN ON THE STRONGER
SIDE...WE MAY HAVE TO BUMP UP THOSE HIGHS LATER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1240 PM CDT SUN AUG 9 2015
OCCASIONAL MVFR CEILINGS THROUGH THE AFTERNOON THEN THUNDERSTORMS
BECOME THE FOCUS AFTER ABOUT 20Z. A FEW OF THESE STORMS WILL BE
STRONG TO SEVERE. THE MAIN THREAT FOR MVFR CEILINGS AND
THUNDERSTORMS WILL BE BEFORE ABOUT 5Z.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...08
SHORT TERM...JH
LONG TERM...
AVIATION...08
AREA FORECAST DISCUSSION
NWS AMARILLO TX
431 PM CDT SUN AUG 9 2015
.DISCUSSION...
A WEAK BOUNDARY SLOWLY SAGGING SOUTH SHOULD BE THE FOCUS FOR STORM
DEVELOPMENT THIS AFTERNOON AND INTO THE OVERNIGHT HOURS. STORMS COULD
ALSO DEVELOP ALONG AN AREA OF CONVERGENCE FROM CANADIAN TO BUSHLAND.
THIS DEVELOPMENT IS SHOWN IN THE HRRR OUTPUT, BUT MORNING CLOUD
COVER HAS SLOWED THE WARMING IN THESE AREAS WHICH MAY DELAY THE
INITIATION TO LATER IN THIS EVENING. ANY STORMS THAT DO DEVELOP ALONG
THIS CONVERGENCE AREA SHOULD MOVE OFF INTO WESTERN OKLAHOMA LATER
THIS EVENING AS A WEAK SHORTWAVE SEEN IN WATER VAPOR IMAGERY OVER
SOUTHERN NEW MEXICO ROUND THE RIDGE. THIS SHORTWAVE SHOULD ALSO HELP
CONVECTION TO DEVELOP ALONG THE SOUTHWARD MOVING BOUNDARY. BOTH
ROUNDS OF STORMS SHOULD HAVE THE POTENTIAL TO BECOME STRONG TO
MARGINALLY SEVERE WITH AROUND 2000 J/KG AND DEEP LAYER SHEAR AROUND
20-25KT. HEAVY RAIN WILL ALSO BE OF CONCERN WITH ANY STORM THAT
DEVELOPS. PWAT VALUES OVERNIGHT CONTINUE TO HOVER RIGHT AROUND THE
+2SD FOR THIS TIME OF YEAR. WHILE AVERAGE FORECAST AMOUNTS RANGE FROM
A QUARTER OF AN INCH UP TO THREE QUARTERS OF AN INCH, THERE REMAINS
AS RISK FOR LOCALIZED AMOUNTS UP TO 1.5 INCHES WITH THE STORMS
THROUGH MONDAY MORNING.
A FEW LINGERING SHOWERS AND THUNDERSTORMS ARE POSSIBLE FOR THE
MONDAY MORNING COMMUTE BUT RAINFALL AMOUNTS FROM THESE STORMS SHOULD
BE LESS THAN THE OVERNIGHT STORMS. AFTER A BRIEF LULL AROUND MIDDAY
THE NEXT ROUND OF STORMS IS EXPECTED TO DEVELOP AS THE UPPER LEVEL
FLOW BECOMES MORE NORTHWESTERLY. THE WIND SHIFT, WHILE MOSTLY SOUTH
OF THE PANHANDLES, SHOULD STILL BE POSITIONED TO ALLOW SIZABLE
ISENTROPIC UPGLIDE MONDAY AFTERNOON INTO TUESDAY. THE THOUGHT OF A
FLASH FLOOD WATCH FOR MONDAY AFTERNOON INTO TUESDAY MORNING
CONTINUES TO COME UP BUT THERE HAS BEEN SIGNIFICANT DISCREPANCIES
BETWEEN MODEL RUNS. YESTERDAY THE GFS SHOWED UP TO 3 INCHES FOR THE
NORTHWEST AND SHOWS AROUND AN INCH STORM TOTAL (JUST LIKE THE ECMWF
SHOWED YESTERDAY). TODAY IT`S THE MORNING NAM WHICH SHOWS 2-4 INCHES
ACROSS THE WESTERN OKLAHOMA PANHANDLE WITH EVEN HIGHER AMOUNTS IN
SOUTHEASTERN COLORADO (ALTHOUGH THE 18Z RUN HAS ALREADY BEGUN TO
BACK OFF ON THESE AMOUNTS). AS A RESULT OF THESE DISCREPANCIES WILL
HOLD OFF ON ISSUING A WATCH UNTIL THE IMPACTED AREA CAN BE NARROWED
DOWN. RAINFALL AMOUNTS WITH THIS ROUND ARE EXPECTED TO BE HIGHEST
ACROSS THE NORTHERN TEXAS AND OKLAHOMA PANHANDLES AND RANGE BETWEEN
THREE QUARTERS OF AN INCH UP TO 1.5 INCHES WITH LOCALLY HIGHER
AMOUNTS POSSIBLE. AMOUNTS ACROSS THE SOUTHERN TEXAS PANHANDLE LOOK TO
RANGE BETWEEN A QUARTER OF AN INCH UP TO THREE QUARTERS OF AN INCH
WITH LOCALLY HIGHER AMOUNTS POSSIBLE.
WEDNESDAY THROUGH THE REST OF THE WEEK...THE RIDGE CONTINUES TO MOVE
INTO THE CONTINENTAL DIVIDE TO KEEP THE PANHANDLES WITH A NORTH-
NORTHWEST FLOW REGIME ALOFT. THIS WILL KEEP OFF AN ON RAIN CHANCES IN
THE FORECAST AND SLIGHTLY COOLER TEMPERATURES THROUGH THE END OF THE
WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMARILLO TX 70 88 68 86 68 / 50 30 40 30 20
BEAVER OK 70 90 70 86 67 / 50 40 50 30 20
BOISE CITY OK 65 86 65 80 64 / 40 50 70 40 20
BORGER TX 73 90 71 86 70 / 50 40 50 30 20
BOYS RANCH TX 70 90 70 86 67 / 40 50 50 30 20
CANYON TX 69 89 70 87 67 / 40 30 30 30 10
CLARENDON TX 73 92 71 88 70 / 30 30 20 20 10
DALHART TX 68 87 68 83 65 / 40 50 70 30 20
GUYMON OK 69 90 68 83 67 / 40 40 70 40 20
HEREFORD TX 69 90 69 87 67 / 30 40 30 30 10
LIPSCOMB TX 72 92 71 87 68 / 60 30 40 30 20
PAMPA TX 70 88 69 84 68 / 50 30 50 30 20
SHAMROCK TX 71 94 71 89 69 / 40 30 30 30 20
WELLINGTON TX 71 96 71 91 70 / 30 20 20 20 10
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
2/14
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
323 PM CDT SUN AUG 9 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 323 PM CDT SUN AUG 9 2015
MAIN FOCUS IS THE RAIN RISK TONIGHT THROUGH MONDAY. FRONTAL
BOUNDARY HELPED TO MAINTAIN A FOCUS FOR CONVECTIVE DEVELOPMENT
ACROSS CENTRAL MN THROUGH THE DAY...ASSISTED GREATLY BY THE MCV
FROM THE SOUTH DAKOTA CONVECTION OVERNIGHT. THIS CLUSTER RAMPED
UP SHORTLY AFTER THE NOON HOUR...AND WAS PROGRESSING ACROSS
NORTHERN WI. MEANWHILE...THE TRAILING EDGE OF THE FRONT REACHED
WEST BACK INTO EASTERN SD. SOUTHEAST WINDS HAVE FED BOUNDARY LAYER
MOISTURE INTO THIS BOUNDARY...AND AS AFTERNOON HEATING MAXIMIZED
INSTABILITY...NEW CONVECTION IS FORMING. WATER VAPOR IMAGERY AND
MODELS SHOW A SHORT WAVE MOVING THROUGH THE FLOW IN THIS AREA AS
WELL. EXPECT THIS SD CONVECTIVE ACTIVITY TO MOVE EAST TOWARD THE
AREA OVERNIGHT. HAVE INCREASED RAIN CHANCES IN THE FORECAST DURING
THE EVENING HOURS...AND A LITTLE BIT OVERNIGHT. MODELS ARE
INSISTENT THAT THIS WILL ALL WEAKEN OR EVEN FIZZLE OUT
OVERNIGHT...AND HENCE OUR LOWER POP CHANCES. BUT IF THE SD
ACTIVITY CONTINUES TO RAMP UP AND GENERATES ANOTHER MCV...THOSE
OVERNIGHT CHANCES WILL HAVE TO BE INCREASED.
DURING THE DAY MONDAY...THE WAVE PASSES...AND THE FRONT SHIFTS
SOUTH OF THE REGION. ANOTHER SHORT WAVE TROUGH ROTATES AROUND THE
HUDSON BAY UPPER TROUGH AND DROPS INTO THE GREAT LAKES LATE
MONDAY. THIS LOOKS TO GENERATE SOME AFTERNOON SHRA/TSRA...BUT THAT
ACTION LOOKS TO REMAIN NORTHEAST OF OUR FORECAST AREA. THIS ALSO
BEARS WATCHING HOWEVER...AS SOMEWHAT STEEP LAPSE RATES IN THE COOL
AIR REGIME COULD ASSIST DEVELOPMENT OF ROBUST CUMULUS THAT COULD
GENERATE PRECIP.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 323 PM CDT SUN AUG 9 2015
THE TROUGH PASSES AND HIGH PRESSURE MOVES IN BY MONDAY NIGHT.
COOLER AIR WILL ALSO BE POURING IN...SETTING THE STAGE FOR A
COUPLE OF COOL NIGHTS. LOWS LOOK TO BE IN THE 50S AND LOWER 60S
BY TUESDAY MORNING...AND EVEN A BIT COOLER WEDNESDAY MORNING.
WOULD NOT BE SURPRISED TO SEE SOME 40S OVER THE TYPICAL COOL SPOT
AREAS. WITH THE COOL TEMPS AND LIGHT WINDS BOTH TUE/WED MORNING...
ANTICIPATE THAT VALLEY FOG WILL ONCE AGAIN BECOME PREVALENT.
THE RIDGE HOLDS THROUGH THURSDAY BEFORE THE NEXT SHORT WAVE MOVES
OVER THE TOP AND DROPS INTO THE AREA BY THURSDAY NIGHT. WHILE THE
GREATEST SUPPORT LOOKS TO PRIMARILY BE NORTH AND EAST OF THE
AREA...A CROSSING BOUNDARY AND ENOUGH THERMODYNAMIC ASSISTANCE IS
PRESENT FOR AT LEAST A CHANCE FOR SOME RAIN.
A BRIEF PERIOD OF RIDGING LOOKS LIKELY FRI/SAT...ALONG WITH A
RETURN TO MORE WARM AND HUMID WEATHER. THE MODELS ARE TRENDING
TOWARD A SIGNIFICANT UPPER SYSTEM OVER WESTERN CANADA...PUSHING
THE UPPER RIDGE OVER OUR AREA...AND EVENTUALLY LEADING TO THE
PASSAGE OF A STRONG COLD FRONT. AT THIS TIME IT LOOKS LIKE THIS
WOULD OCCUR LATE SUNDAY OR EVEN MONDAY. BUT THE TIMING IS
DIFFICULT TO PIN DOWN IN THIS EVOLVING PATTERN SHIFT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1204 PM CDT SUN AUG 9 2015
WEAK COLD FRONT ACROSS FAR NORTHWEST WISCONSIN INTO SOUTHWEST
MINNESOTA IS EXPECTED TO CONTINUE MOVING SLOWLY SOUTHEAST WHILE
WEAKENING. WHAT REMAINS OF THE FRONT SHOULD PASS THROUGH THE AREA
THIS EVENING WITH A WIND SHIFT TO THE NORTH NORTHWEST BUT WITH
VERY LIGHT WIND SPEEDS. CONVECTIVE ACTIVITY ALONG THE FRONT OVER
WESTERN MINNESOTA IS SHOWN BY THE 09.15Z RUN OF THE HRRR TO
CONTINUE MOVING EAST BEFORE WEAKENING OVER WISCONSIN WHILE STAYING
TO THE NORTH OF BOTH TAF SITES. OTHER CONVECTION MAY FORM OVER
SOUTHWEST MINNESOTA AND MOVE SOUTHEAST INTO IOWA MISSING THE TAF
SITES TO THE SOUTH. FOR NOW...DO NOT PLAN TO SHOW ANY RAIN CHANCES
FOR EITHER SITE AND WILL BRING THE FRONT THROUGH WITH JUST A HIGH
VFR CEILING. SOME POTENTIAL FOR FOG AGAIN TONIGHT AS THE WINDS
WILL BE LIGHT AND MAY NOT CHANGE OVER THE BOUNDARY LAYER ENOUGH TO
HELP LOWER THE DEW POINTS. RIGHT NOW THINKING THE CLOUDS WITH THE
FRONT WILL KEEP THE FOG FROM FORMING...BUT IF THESE DO NOT
OCCUR...THE CONDITIONS FOR FOG FORMATION WILL BE MUCH BETTER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...MW
LONG TERM...MW
AVIATION...04
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 214 PM CDT SUN AUG 9 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A COLD
FRONT STRETCHING FROM SOUTHWEST MINNESOTA TO THE WESTERN UPPER
PENINSULA. THIS FRONT HAS BEEN MOSTLY INACTIVE SO FAR
TODAY...OUTSIDE OF A FEW SHOWERS OVER VILAS COUNTY EARLY THIS
MORNING. LOW STRATUS OVER NORTHERN WISCONSIN HAVE HELD BACK TEMPS
SOMEWHAT...WHICH IS KEEPING INSTABILITY LIMITED TO UNDER 800 J/KG SO
FAR THIS AFTERNOON. THE STRATUS IS SHOWING NO SIGNS OF BREAKING UP
EITHER. BIGGER CONCERNS REVOLVE AROUND THE SHOWERS AND
THUNDERSTORMS MOVING INTO WESTERN WISCONSIN ASSOCIATED WITH A
SHORTWAVE IMPULSE. THUNDERSTORMS ARE EXPANDING WITHIN THE
INSTABILITY AXIS OVER NORTHWEST WISCONSIN...AND A ROUGH TIMING SHOWS
STORMS MOVING INTO NORTH-CENTRAL WISCONSIN IN THE 3-5PM RANGE. DUE
TO THE LIMITED INSTABILITY...STILL THE SEVERE THREAT IS RATHER LOW.
BUT SMALL HAIL AND GUSTY STRAIGHT LINE WINDS WILL BE POSSIBLE.
FORECAST CONCERNS REVOLVE AROUND THUNDERSTORM POTENTIAL.
TONIGHT...THE COLD FRONT WILL REMAIN NEARLY STATIONARY FOR THE REST
OF THE AFTERNOON...AND THEN SHIFT SOUTHEAST AS THE SHORTWAVE IMPULSE
MOVES ACROSS THE AREA THIS EVENING. SHOWERS AND THUNDERSTORMS NOW
LOOK LIKELY ACROSS MOST OF THE AREA THIS EVENING...EXCEPT FOR MAYBE
THE SOUTHERN TIER. HAVE INCREASED PRECIP CHANCES INTO THE LIKELY
RANGE...AS THE SHORTWAVE SHOULD BE ABLE TO INTERACT WITH SOME OF
LINGERING DAYTIME INSTABILITY. THE RAINFALL SHOULD HELP GIVE SOME
SOUTHEAST PUSH TO THE COLD FRONT WHICH WILL MOVE INTO EAST-CENTRAL
WISCONSIN LATE. WITH THE RAINFALL AND FRONT NEARBY...THINK LOW
STRATUS AND/OR FOG WILL REDEVELOP AFTER MIDNIGHT. SOME DENSE FOG
LIKE EARLY THIS MORNING IS POSSIBLE IN SPOTS.
MONDAY...THE FRONT DOES NOT MAKE MUCH PROGRESS SOUTHWARD...LEAVING
NORTHEAST WISCONSIN IN CLOSE PROXIMITY TO THE FRONT. THOUGH HAVE
SOME CONCERN THAT TONIGHTS RAIN WILL PUSH THE FRONT SOUTH OF THE
AREA...LEFT A CHANCE OF STORMS IN THE FORECAST DURING THE AFTERNOON
OVER THE EAST. NO SEVERE STORMS ARE EXPECTED DUE TO MEAGER 0-6KM
SHEAR OF 10 KTS. HIGHS TO RANGE FROM THE MID 70S TO LOW 80S.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 214 PM CDT SUN AUG 9 2015
A TRANSITION IN THE UPPER LEVEL FLOW IS EXPECTED STARTING
TUESDAY...WHEN HIGH PRESSURE WILL STRENGTHEN OVER THE ROCKIES IN A
BLOCKING PATTERN THAT WILL KEEP THE NORTHEAST U.S. UNDER A LOW
PRESSURE TROUGH AND WISCONSIN UNDER A NORTHWEST FLOW. THIS
SCENARIO WILL PRODUCE DRIER CONDITIONS IN GENERAL FOR NORTHEAST
WISCONSIN...ALTHOUGH MODELS AGREE ON A CHANCE FOR PRECIPITATION
LATER IN THE WORK WEEK AS A WEAK COLD FRONT SWEEPS DOWN ON THE
NORTHWEST FLOW OUT OF CANADA.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1149 AM CDT SUN AUG 9 2015
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS
AFTERNOON ALONG A WEAK COLD FRONT OVER NORTHERN WISCONSIN. AN UPPER
LEVEL DISTURBANCE OVER MINNESOTA WILL HELP MAKE COVERAGE MORE
WIDESPREAD...SO INCLUDED A TEMPO GROUP FOR STORMS AT AUW/CWA THIS
EVENING. UNCERTAINTY INCREASES FURTHER EAST DUE TO THE LATER
ARRIVAL OF THE FRONT/UPPER DISTURBANCE AND NIGHT TIME STABILIZATION.
ESPECIALLY IF THERE IS RAINFALL...LOWER CIGS AND VSBYS ARE EXPECTED
TO REDEVELOP TONIGHT AND THEN IMPROVE AGAIN BY MID MORNING ON MONDAY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......ML
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1204 PM CDT SUN AUG 9 2015
.SHORT TERM...(TODAY INTO MONDAY)
ISSUED AT 230 AM CDT SUN AUG 9 2015
TWO AREAS OF CONVECTION EARLY THIS MORNING. FIRST IS AN MCS FUELED
BY LOW LEVEL MOISTURE TRANSPORT AND DRIVEN BY AN UPPER LEVEL
SHORTWAVE - TRACKING EAST ACROSS EASTERN IA. RADAR AND MESO MODEL
TRENDS CONTINUE TO MOVE THIS EAST/SOUTHEAST...LIKELY AWAY FROM
NORTHEAST IA/SOUTHWEST WI BY 12Z. MEANWHILE TO THE NORTH...SCATTERED
CONVECTION OVER NORTHEAST MN/NORTHWEST WI IS BEING SPARKED BY A
FRONTOGENETIC REGION ASSOCIATED WITH A SHORTWAVE SLIDING ACROSS
SOUTHERN CANADA. WANING INSTABILITY/WEAKENING MOISTURE TRANSPORT IN
THIS REGION SHOULD LEAD TO A DECREASE IN COVERAGE THROUGH THE EARLY
MORNING HOURS.
THIS NORTHERN BOUNDARY COULD ACT TO SPARK A FEW MORE SHOWERS/STORMS
LATER TODAY AS A RIBBON OF INSTABILITY IS ANTICIPATED TO REDEVELOP
AROUND IT. ITS NOT AN OVERLY CONVERGENT BOUNDARY...BUT ENOUGH TO
INCLUDE SMALL CHANCES...ESPECIALLY LATE AFTERNOON/EARLY EVENING.
NEXT...RIPPLE IN THE UPPER LEVEL FLOW IS PROGGED TO MOVE SOUTHEAST
ACROSS THE NORTHERN PLAINS...TAKING AIM ON IA EARLY MONDAY MORNING.
MODELS HAVE ANOTHER MCS DEVELOP IN RESPONSE...WITH THE BRUNT OF ITS
IMPACT AGAIN FOCUSED ON THE HAWKEYE STATE. THERE WILL LIKELY BE SOME
INTERACTION BETWEEN THE SHORTWAVE AND LINGERING SFC FRONT...WITH
SOME PCPN CHANCES EXTENDING NORTH/EAST ALONG THE BOUNDARY.
HOWEVER...THE BULK OF THE PCPN THREAT/AMOUNTS LOOKS TO BE JUST
WEST/SOUTH OF THE LOCAL AREA.
OVERALL...THOSE IN THE I-90 CORRIDOR AND NORTH WHO WERE HOPING FOR
SOAKING RAINS MIGHT BE DISAPPOINTED AS THE HIGHER CHANCES WILL HOLD
SOUTH OF THERE THROUGH MONDAY.
.LONG TERM...(TUESDAY INTO SATURDAY)
ISSUED AT 230 AM CDT SUN AUG 9 2015
MODELS REMAIN IN GOOD AGREEMENT WITH AMPLIFYING AN UPPER LEVEL RIDGE
OVER THE HEART OF THE U.S. THIS WEEK...KEEPING THE UPPER MISSISSIPPI
RIVER VALLEY UNDER NORTHWEST FLOW. AT THE SFC...A HIGH IS STILL
PROGGED TO DROP OUT OF CANADA AND ACROSS THE AREA TUE-THU. THE SETUP
IS FAVORABLE FOR RIVER VALLEY FOG...WITH WED MORNING CURRENTLY
LOOKING THE MOST LIKELY.
THE UPPER LEVEL RIDGE NEVER QUITE MAKES IT TO THE GREAT LAKES AS THE
VARIOUS LONG TERM MODELS DRIVE SHORTWAVE TROUGHS ACROSS THE TOP OF
IT...WITH SOME HINTS THAT EITHER THE FLOW WILL BECOME MORE ZONAL
TOWARD THE END OF NEXT WEEKEND...OR THE RIDGE WILL REESTABLISH
ITSELF OVER THE WEST COAST.
IT SHOULD STAY DRY INTO THU...BUT THEN THE GFS/EC DROP A BIT OF
UPPER LEVEL ENERGY OVER THE RIDGE AND ACROSS THE GREAT LAKES THU
AFTERNOON/NIGHT. WHILE THE BULK OF THE LIFT STAYS NORTH/EAST OF THE
LOCAL AREA...AN ASSOCIATED SFC FRONT LOOKS TO DROP SOUTH ACROSS THE
REGION. SOME MOISTURE TRANSPORT INTO THE BOUNDARY AND INSTABILITY TO
PLAY WITH SHOULD SPARK AT LEAST SCATTERED CONVECTION ALONG IT. THIS
BOUNDARY WILL SLIDE SOUTH BUT COULD GET CAUGHT UP WEST-EAST ACROSS
IA/ILL...REMAINING A POTENTIAL FOCUS FOR SHOWERS/STORMS INTO THE
WEEKEND.
FOR TEMPERATURES...WHILE THE RIDGE AXIS STAYS TO THE WEST...MODELS
ARE STARTING TO SUGGEST THAT SOME OF THAT WARMER AIR WILL WORK
ACROSS THE FORECAST AREA. INSTEAD OF AT OR BELOW NORMAL HIGHS...TEMPS
COULD WARM TO AT OR ABOVE NORMAL AS THE WEEK PROGRESSES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1204 PM CDT SUN AUG 9 2015
WEAK COLD FRONT ACROSS FAR NORTHWEST WISCONSIN INTO SOUTHWEST
MINNESOTA IS EXPECTED TO CONTINUE MOVING SLOWLY SOUTHEAST WHILE
WEAKENING. WHAT REMAINS OF THE FRONT SHOULD PASS THROUGH THE AREA
THIS EVENING WITH A WIND SHIFT TO THE NORTH NORTHWEST BUT WITH
VERY LIGHT WIND SPEEDS. CONVECTIVE ACTIVITY ALONG THE FRONT OVER
WESTERN MINNESOTA IS SHOWN BY THE 09.15Z RUN OF THE HRRR TO
CONTINUE MOVING EAST BEFORE WEAKENING OVER WISCONSIN WHILE STAYING
TO THE NORTH OF BOTH TAF SITES. OTHER CONVECTION MAY FORM OVER
SOUTHWEST MINNESOTA AND MOVE SOUTHEAST INTO IOWA MISSING THE TAF
SITES TO THE SOUTH. FOR NOW...DO NOT PLAN TO SHOW ANY RAIN CHANCES
FOR EITHER SITE AND WILL BRING THE FRONT THROUGH WITH JUST A HIGH
VFR CEILING. SOME POTENTIAL FOR FOG AGAIN TONIGHT AS THE WINDS
WILL BE LIGHT AND MAY NOT CHANGE OVER THE BOUNDARY LAYER ENOUGH TO
HELP LOWER THE DEW POINTS. RIGHT NOW THINKING THE CLOUDS WITH THE
FRONT WILL KEEP THE FOG FROM FORMING...BUT IF THESE DO NOT
OCCUR...THE CONDITIONS FOR FOG FORMATION WILL BE MUCH BETTER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...04