Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/10/13
AREA FORECAST DISCUSSION
NWS EUREKA CA
349 PM PDT THU AUG 8 2013
.SYNOPSIS...AN UPPER LEVEL LOW CONTINUES TO SIT JUST OFFSHORE.
THIS MAY BRING SOME ISOLATED THUNDERSTORMS TO THE INLAND AREAS
THIS EVENING AND TONIGHT...MAINLY NORTH OF HIGHWAY 36. THERE IS A
SLIGHT CHANCE OF THUNDERSTORMS ALONG THE COAST TONIGHT NORTH OF
ORICK. FRIDAY THUNDERSTORMS ARE POSSIBLE AGAIN BEFORE HIGH
PRESSURE RETURNS FOR THE WEEKEND.
&&
.SHORT TERM...UPPER LEVEL LOW CONTINUES TO SIT AND SPIN THIS
AFTERNOON. IT CURRENTLY IS CENTERED SOUTHWEST OF CAPE MENDOCINO.
THIS IS CONTINUING TO BRING SHOWERS AND THUNDERSTORMS TO NORTHERN
CA. HOWEVER...IN THE EUREKA CWA CONVECTION IS STRUGGLING. THIS
LOOKS TO BE DUE A AN AREA OF POOR LAPSE RATES AROUND 600 MB. THE
NAM AND RUC ARE STILL INDICATING THAT LATER THIS EVENING A FEW
SHOWERS WILL POP UP...MAINLY IN TRINITY COUNTY. TRIMMED BACK POPS
SLIGHTLY FOR THIS AFTERNOON...BUT MAINLY LEFT THINGS ALONE WITH
ISOLATED TO SCATTERED COVERAGE. ALONG THE COAST SKIES HAVE
PARTIALLY CLEARED OUT WITH THE INCREASED MIXING...BUT EXPECT
CLOUDS WILL RETURN THIS EVENING. THIS INCREASED MIXING HAS ALSO
LIFTED TEMPERATURES INTO THE LOW 60S AT THE COAST.
LATE TONIGHT INTO FRIDAY MORNING THE MODELS ARE SHOWING A
SHORTWAVE ROTATING AROUND THE LOW. MODELS ARE INDICATING SOME
ELEVATED INSTABILITY WITH THIS SO IT MAY KICK OFF A FEW
THUNDERSTORMS. THE BEST CHANCE WILL BE NORTH OF HWY 299. SINCE
THESE ARE ELEVATED SEE NO REASON IF THEY DO FORM THAT THEY WONT
MAKE IT ALL THE WAY THE COAST. AS WITH MOST NOCTURNAL
THUNDERSTORMS IN THIS AREA CONFIDENCE IS LOW. THERE IS AN OUTSIDE
CHANCE A FEW COULD MAKE IT AS FAR SOUTH AS EUREKA...BUT WAS NOT
CONFIDENT ENOUGH IN THIS TO PUT THEM IN THE FORECAST. FRIDAY
AFTERNOON THERE IS AN ADDITIONAL CHANCE FOR THUNDERSTORMS OVER THE
INLAND AREAS. LAPSE RATES LOOK MARGINAL...SO LEFT THE FORECAST
BASICALLY UNCHANGED. ALONG THE COAST EXPECT THERE WILL BE CLEARING
AGAIN IN THE AFTERNOON AND TEMPERATURES MAY REACH THE LOW 60S ONCE
AGAIN. INLAND TEMPERATURES WILL BE SIMILAR TO TODAY AS WELL.
SATURDAY AND SUNDAY THE LOW STARTS TO PULL OFF TO THE NORTH AND
THE AIR STABILIZES. SATURDAY THERE IS AN SLIGHT CHANCE FOR SOME
THUNDERSTORMS ALONG THE SISKIYOU/TRINITY COUNTY...BUT EVEN THAT IS
DOUBTFUL. TEMPERATURES INLAND WILL GRADUALLY START TO WARM AGAIN
AS THE LOW PULLS OFF THE NORTH. ALONG THE COAST THERE MAY BE SOME
CLEARING EACH AFTERNOON...BUT THIS WILL LIKELY BE BRIEF. MKK
&&
.LONG TERM(MONDAY THROUGH THURSDAY)...
NOT MUCH TO SAY REGARDING THE FORECAST NEXT WEEK. IT SHOULD BE A
PRETTY QUIET PERIOD OVERALL, AND WHILE WE LEFT SOME `GHOST POPS`
OVER THE MTS OF ERN MENDO/TRINITY MON PM, THE ATMOSPHERE LOOKS
INCREASINGLY DRY AND STABLE HEADING THROUGH THE WEEK. TEMPERATURES
WILL WARM TO NEAR SEASONABLE LEVELS WITH HIGHS IN THE LOW 90S ACROSS
THE WARMER INTERIOR VALLEYS. AT THE COAST, SOME INCREASE IN
NORTHERLY WINDS AND THE LACK OF A STRONG RIDGE OF HIGH PRESSURE
LENDS HOPE FOR SOME PARTIALLY SUNNY AFTERNOONS, ESPECIALLY ALONG THE
MENDOCINO COAST. HOWEVER GIVEN THE TIME OF YEAR, AND STILL PLENTY OF
BOUNDARY LAYER MOISTURE AROUND WITH NORTHERLY AND ONSHORE FLOW,
MORNING AND OVERNIGHT LOW CLOUDS AND FOG WILL REMAIN PERSISTENT. AAD
&&
.AVIATION...RELATIVELY LOW CONFIDENCE FORECAST TONIGHT. CURRENT
VISIBLE IMAGERY SHOWS 1000-1500FT DECK OVER THE INLAND COASTAL HILLS
OF HUMBOLDT COUNTY WITH SCATTERED LOWER STRATUS IN PATCHES ALONG THE
MENDOCINO COAST AND DEL NORTE COUNTY NEAR KCEC. EXPECT THE CLEAR
SPOTS TO FILL BACK BETWEEN 02Z AND 05Z AND GO BELOW 1000FT BY
8Z-12Z. HOWEVER WITH THE UPPER LOW MOVING THROUGH WOULD NOT BE
SURPRISED TO SEE THE CEILINGS LIFT A BIT BEFORE COMING BACK DOWN
CLOSER TO DAWN TOMORROW. HIGHER CONFIDENCE THAT VSBYS WILL STAY
MOSTLY UNRESTRICTED, DESPITE THE GUIDANCE SHOWING OTHERWISE.
CLEARING TOMORROW SHOULD BE A BIT EASIER TO COME BY WITH THE LESS
STABLE ENVIRONMENT, BUT DO NOT EXPECT MUCH MORE THAN A FEW HOURS
WITH LIGHT NORTHERLY WINDS IN THE BL NOT SUPPORTING MUCH MIXING.
CIGS SHOULD AT LEAST BE ABOVE 1000 OR 1500 FT AFTER EARLY TO MID
MORNING. AWAY FROM THE COAST...THERE WILL BE A THREAT FOR SCATTERED
SHOWERS AND A STRAY THUNDERSTORM OR TWO OVER THE SISKIYOUS OR
TRINITY ALPS. SMOKE NEAR FIRES IN SRN SISKIYOU COUNTY WILL CONTINUE
TO LOWER VISIBILITY IN LOCALIZED AREAS. AAD
&&
.MARINE...VERY LITTLE CHANGE TO THE PREVIOUS FORECAST. SEAS WERE
RUNNING 2 TO 4 FEET ACROSS THE COASTAL WATERS AS OF THIS WRITING,
WITH VERY LIGHT WINDS WITHIN 5 TO 10 NM OF SHORE. NO ASCAT PASS
YET TODAY, BUT NORTHERLY WINDS ARE PROBABLY PICKING UP A BIT MORE
ACROSS THE OUTER WATERS BEYOND 10 NM, ON THE ORDER OF 10 TO 15
KNOTS, ESPECIALLY TO THE LEE OF CAPE MENDOCINO. ISOLATED SHOWER
ACTIVITY WILL BE POSSIBLE LATER TONIGHT AND TOMORROW MORNING. WITH
THE UPPER LOW STILL TRACKING THROUGH, BUT DO NOT EXPECT ANY
LIGHTNING AS THE BETTER DYNAMICS AND FORCING SHIFT EAST AND NORTH.
AS THE UPPER LOW PASSES BY AND RIDGING TRIES TO BUILD BACK IN,
NORTHERLY WINDS WILL INCREASE BY SUNDAY OR MONDAY. HOWEVER, WE ARE
THINKING 20-25 KTS OVER THE SRN OUTER WATERS AND NEAR CAPE
MENDOCINO AT WORST, AS THE RIDGE REMAINS FLAT AT BEST, AND HIGH
PRESSURE OFFSHORE REMAINS WEAK. OTHERWISE, OUTSIDE OF LOCALLY
GENERATED LOW WAVES GENERATED BY THESE NORTHERLIES, A NW SWELL
AROUND 10-12 SEC PERIOD WILL PEAK AT ABOUT 4 FT ON SATURDAY BEFORE
GRADUALLY DECAYING. A 1-2 FT SOUTHERLY SWELL NEAR 14 SEC PERIOD
MAY ALSO BE NOTICEABLE WHERE THE WINDS AND SEAS ARE OTHERWISE
LIGHT AND LOW. AAD
&&
.FIRE WEATHER...A FEW SHOWERS HAVE STARTED TO POP UP THIS
AFTERNOON SO IT LOOKS REASONABLE THAT WE WILL GET SOME
STRIKES...ALTHOUGH THE EXACT COVERAGE AND LOCATION MAY BE
SLIGHTLY LESS THAN FORECASTED. LEFT THE RED FLAG WARNING IN PLACE
FOR THIS EVENING. LATE TONIGHT A SHORTWAVE ROTATING AROUND THE LOW
LOOKS TO SPARK OFF SOME THUNDERSTORMS. EXPECT THESE WILL MAINLY BE
NORTH OF HWY 299 SO UPGRADED THE FIRE WEATHER WATCHES TO WARNINGS
IN THE NORTH AND CANCELLED THE WATCHES IN THE SOUTH. CONFIDENCE
REMAINS LOW ON THIS NOCTURNAL CONVECTION. FRIDAY AFTERNOON SOME
CONVECTION MAY RETURN...HOWEVER THE LAPSE RATES ALOFT LOOK A BIT
MARGINAL SO LEFT THE FIRE WEATHER WATCH IN PLACE. THE BEST CHANCE
FOR THUNDERSTORMS LOOK TO BE ALONG THE SISKIYOU/TRINITY COUNTY
BORDER. FOR THE WEEKEND THE THREAT LOOKS TO DIMINISH AS THE LOW
PULLS AWAY SO IT IS UNLIKELY THAT ANY ADDITIONAL WATCHES OR
WARNINGS WILL BE ISSUED FOR THEN. MKK
&&
.EKA WATCHES/WARNINGS/ADVISORIES...
CA...RED FLAG WARNING UNTIL 11 PM PDT THIS EVENING CAZ076.
FIRE WEATHER WATCH FROM FRIDAY MORNING THROUGH FRIDAY
EVENING CAZ003-004-076.
RED FLAG WARNING UNTIL 11 AM PDT FRIDAY CAZ003-004.
NORTHWEST CALIFORNIA COASTAL WATERS...NONE.
&&
$$
VISIT US AT HTTP://WWW.WEATHER.GOV/EUREKA
FOLLOW US ON FACEBOOK AND TWITTER AT:
HTTP://WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.EUREKA.GOV
HTTP://WWW.TWITTER.COM/NWSEUREKA
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
742 PM MDT FRI AUG 9 2013
.UPDATE...CONVECTION ALREADY DECREASING ACROSS THE AREA. MAY SEE
SHOWERS AND STORMS STAY ALIVE AND MOVE INTO LINCOLN COUNTY. WILL
HAVE THE HIGHEST POPS HERE. DECREASED POPS MAINLY TO 10S ACROSS
THE AREA FOR POSSIBLE STRAY SHOWERS OR STORMS THROUGH MIDNIGHT.
THE RAP AND NAM HINT AT SOME FOG LATE TONIGHT OVER WASHINGTON AND
LINCOLN COUNTIES. PREVIOUS FORECAST HAD A MENTION OF FOG AND WILL
ADJUSTED THE FORECAST TO THE CURRENT TREND OF THE MODELS.
&&
.AVIATION...JUST A VERY SMALL THREAT FOR STORMS THROUGH THE REST
OF THE EVENING...NOT ENOUGH TO MENTION IN THE TAFS. EXPECT MID AND
HIGHS CLOUDS TO CONTINUE THROUGH TONIGHT AND INTO SATURDAY.
SOUTHERLY WINDS ARE EXPECTED TO LINGER THROUGH 12Z...WITH LIGHT
WINDS AFTER THAT. ANOTHER CHANCE FOR STORMS SATURDAY AFTERNOON AND
EARLY EVENING.
&&
.PREV DISCUSSION... /ISSUED 328 PM MDT FRI AUG 9 2013/
SHORT TERM...MID/UPPER-LEVEL RIDGE OVER THE ROCKY MOUNTAIN REGION
NEXT 24 HOURS WITH A NUMBER OF POORLY DEFINED PERTABATIONS ROUNDING
THE TOP OF THE RIDGE. MEAN CIRCULATION ABOUT THE RIDGE WILL CONTINUE
TO DRAW SUBTROPICAL MOISTURE NORTH OVER COLORADO DURING THE SHORT
TERM. ALTHOUGH 600-400 MB SPECIFIC HUMIDITY VALUES ARE PROGGED TO
REMAIN GENERALLY AT OR BELOW 5 G/KG...A THRESHOLD OFTEN ASSOCIATED
WITH HEAVY RAIN POTENTIAL OVER AND ALONG THE FRONT RANGE. WESTERLY
STEERING WINDS WILL CARRY SCATTERED CONVECTION OFF THE HIGH COUNTRY
AND OVER THE ADJACENT HIGH PLAINS NEXT SEVERAL HOURS. CIN HAS ALL
BUT DISAPPEARED...AND SFC BASED CAPES IN THE 500-1000 J/KG RANGE
OVER THE FRONT RANGE AND ON THE PLAINS THIS HOUR. CURRENT INTEGRATED
PRECIPITABLE WATER VALUES NEAR THE FRONT RANGE HOVERING AROUND 0.80
INCH...DOWN FROM THE INCH OR SO IPWS OBSERVED YESTERDAY AT THIS
TIME. IPW HAVE LEVELED OUT AFTER SLOW RISING THIS MORNING. ABOVE
MENTIONED MODELS STILL INDICATE A BROKEN LINE OF T-STORMS
TRANSLATING EAST ACROSS THE I-25 URBAN CORRIDOR DURING THE NEXT 3-5
HOURS. ITS POSSIBLE A COUPLE STORMS COULD PASS OVER DENVER
INTERNATIONAL AIRPORT SOMETIME BETWEEN 22Z-01Z. GUSTS TO AROUND 30
KTS AND RAINFALL RATES OF 0.30 TO 0.60 INCH PER HOUR POSSIBLE WITH
THESE STORMS. CAN/T RULE OUT AN INCH PER HOUR RAIN RATE...BUT STORMS
ARE MOVING FASTER TODAY. SO CHANCES OF SEEING A REPEAT OF THE
INTENSE RAINFALL THAT FLOODED SE DENVER LAST EVENING NOT AS GREAT.
MAY ALSO SEE SOME SMALL HAIL WITH STRONGER STORMS FORMING JUST EAST
OF I-25 EARLY THIS EVENING. STORMS WILL CONTINUE TO MOVE EAST ACROSS
THE PLAINS...BUT MODELS SHOW THIS CONVECTION DYING OUT ALONG THE
WAY. STORMS SHOULD DISSIPATE BEFORE MIDNIGHT WITH CLEARING SKIES
REST OF THE NIGHT. MESOSCALE MODELS ALSO INDICATE GUSTY SOUTHERLY
LOW-LEVEL FLOW DEVELOPING ON THE PLAINS OVERNIGHT...WITH 15-25KT
BNDRY LAYER WINDS DEVELOPING EAST OF THE I-25 CORRIDOR AFTER 06Z.
SPEEDS MAY BE A BIT OVERDONE BUT DIRECTION LOOKS GOOD. WINDS ONE
REASON FOR THE PATCHY FOG FCSTD IN THE FAR EASTERN ZONES LATE
TONIGHT AND EARLY SATURDAY MORNING.
ON SATURDAY...STORM CHANCES DECREASE FOR THE MTNS AND ADJACENT HIGH
PLAINS EVEN WITH A SIMILAR AMOUNT OF MID/UPPER LEVEL MOISTURE OVER
THE REGION. HOWEVER...LOW LEVELS LOOK MUCH DRIER WITH PREVAILING
WESTERLY FLOW. STORM CHANCES GREATER FARTHER OUT ON THE PLAINS WHERE
15-25KT BNDRY LAYER FLOW CONTINUES TO ADVECT MOIST/UNSTABLE AIR
NORTHWARD. BY LATE AFTERNOON...MODELS INDICATE 1000-1500 J/KG CAPES
EAST OF A STERLING-TO-LIMON LINE.. SHEAR NOT ALL THAT GREAT...BUT
CHANCE FOR T-STORMS BETTER OUT THAT WAY. TEMPERATURES NEXT 24 HOURS
WARM BY A FEW DEGS F WITH HIGHS IN THE LOW/MID 80S ON THE PLAINS AND
60S/70S IN THE HIGH COUNTRY.
LONG TERM...MODELS HAVE THE UPPER RIDGE AXIS OVER COLORADO THROUGH
MONDAY NIGHT...WITH WEST-SOUTHWESTERLY FLOW ALOFT TO CONTINUE FOR
THE CWA. THE SYNOPTIC SCALE ENERGY REMAINS BENIGN THROUGH MONDAY
NIGHT. THE BOUNDARY LAYER FLOW LOOKS PRETTY TYPICAL SATURDAY NIGHT
INTO MONDAY. THE GFS HAS SOME EASTERLIES MONDAY AFTERNOON...THE
OTHER MODELS DO NOT. FOR MOISTURE...THE GFS HAS QUITE A BIT IN
THE MID AND UPPER LEVELS SUNDAY NIGHT THROUGH MONDAY...THE
EARLIER PERIODS LOOK DRIER. THE REST OF THE MODELS HAVE OK
MOISTURE...BUT NOTHING LIKE THE GFS. ALL OF THEM DO SHOW MONDAY
AND MONDAY NIGHT A BIT MORE MOIST THEN SATURDAY NIGHT THROUGH
SUNDAY NIGHT. OVER THE WESTERN PLAINS...THE PRECIPITABLE WATER
VALUES ARE IN THE 0.50 TO 0.60 INCH RANGE SUNDAY...THEN THE 0.60
TO 0.70 INCH RANGE SUNDAY NIGHT AND MONDAY. THEY ARE IN THE 0.85
TO 1.00 INCH RANGE FOR THE FAR EASTERN PLAINS THROUGH THE
PERIODS. THE BOUNDARY LAYER DEW POINT PROGGS HAVE READINGS IN THE
30S TO 40S F OVER THE WESTERN THREE-QUARTERS OF THE CWA SATURDAY
NIGHT THROUGH SUNDAY EVENING....WITH SOME 50S OVER THE FAR EAST.
THEY INCREASE A BIT MONDAY AND MONDAY NIGHT...WITH 40S F OVER THE
WESTERN PLAINS AND FOOTHILLS...AND 50S OVER THE REST OF THE
PLAINS. THERE IS SOME CAPE PROGGED OVER THE EASTERN ZONES SATURDAY
NIGHT. THERE IS BETTER COVERAGE OF CAPE LATE DAY SUNDAY AND
MONDAY...BUT VALUES ARE LOW. THE BEST CAPE IS STILL OVER THE FAR
EASTERN BORDER AREA. THE QPF FIELDS SHOW SPARSE COVERAGE AND
SLIGHT AMOUNTS SATURDAY EVENING...SAME FOR LATE DAY SUNDAY. THERE
IS A TAD MORE LATE DAY MONDAY...BUT STILL NOTHING GREAT AND THE
GFS LEADS THE WAY AS USUAL. WILL GO WITH 10-30% POPS SATURDAY
EVENING AND LATE DAY SUNDAY. A BIT HIGHER FOR LATE DAY MONDAY. FOR
TEMPERATURES...SUNDAY`S HIGHS ARE 0-1.5 C WARMER THEN SATURDAY`S.
MONDAY`S HIGHS ARE CLOSE TO SUNDAY`S. FOR THE LATER DAYS...TUESDAY
THROUGH FRIDAY...THE UPPER RIDGE AND IT`S AXIS ARE STILL AROUND
..HOWEVER THE FLOW ALOFT OVER THE CWA BECOMES WEST-
NORTHWESTERLY MOST OF THE FOUR DAYS. MOISTURE DECREASES A BIT.
TEMPERATURES ARE PROGGED TO WARM-UP...ESPECIALLY THURSDAY AND
FRIDAY.
AVIATION...STORMS SLOW TO MOVE OFF THE HIGH TERRAIN...BUT MODELS
STILL SHOW A BROKEN LINE OF SHOWERS/T-STORMS MOVING EAST ACROSS THE
I-25 URBAN CORRIDOR...INCLUDING THE DENVER METRO AREA...BETWEEN
23Z AND 01Z. CIGS OF 6000-7000 FT AGL WITH PASSING STORMS. VSBYS
COULD BRIEFLY LOWER TO 4-5 MILES...BUT CONFIDENCE LOW. MAY ALSO
SEE VARIABLE GUSTS TO 28 KTS AND POSSIBILITY SOME SMALL HAIL.
SKIES CLEAR AFTER STORMS MOVE OUT THIS EVENING WITH DRAINAGE WINDS
SETTING UP. DIA COULD SEE SLY WIND GUSTS TO 20 KTS AFTER MIDNIGHT.
TOMORROW...DAY MOSTLY SUNNY/PARTLY CLOUDY WITH DRIER WEST-
SOUTHWEST FLOW OVER THE AREA. CHANCE OF STORMS ALSO LOWER TOMORROW
WITH 10-20 PCT POPS THAT BEST WE/LL SEE IN THE DENVER METRO AREA
LATE IN THE DAY.
HYDROLOGY...ISOLATED STORMS IN THE MTNS AND NEARBY PLAINS NEXT
3-5 HOURS COULD PRODUCE 0.30 TO 0.60 INCH PER HOUR RAINFALL RATES.
STORM MOVEMENTS FASTER TODAY...SO LOWER FLOOD RISK.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BAKER
LONG TERM....RJK
UPDATE/AVIATION...MEIER
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1039 PM MDT WED AUG 7 2013
.UPDATE...
ISSUED AT 1039 PM MDT WED AUG 7 2013
UPDATED TO CANCEL THE FLASH FLOOD WATCH. MUCH OF THE PRECIPITATION
OVER SOUTHERN COLORADO AND SOUTHEAST UT HAS DIMINISHED AND THE
THREAT OF FLOODING HAS ENDED.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 320 PM MDT WED AUG 7 2013
COMPLEX WEATHER PATTERN AFFECTING THE REGION THIS AFTERNOON. AT
THE SURFACE THERE IS A WEAK QUASI STATIONARY FRONTAL BOUNDARY
DRAPED NEAR THE WY BORDER. ALOFT AND STUCK IN AN UPPER LEVEL RIDGE
AXIS IS A SHORTWAVE TROUGH CENTERED IN SOUTH CENTRAL UT. WHILE THE
CENTER OF ROTATION WILL STRUGGLE TO MOVE EAST TONIGHT AS EVIDENCED
BY THE RAP MODEL...ITS TROUGH WILL ROTATE NORTHEAST INTO SOUTHERN
CO. AXIS OF GREATEST INSTABILITY...MUCAPES 1000 TO 2000 J/KG...
EXTENDS ALONG THE CO/NM BORDER AT THIS TIME AND THIS INDEED IS
WHERE THE MOST VIGOROUS CONVECTION HAS DEVELOPED. THESE STORMS
WILL MOVE NORTHEAST INTO SOUTHWEST CO AND INTO THE SAN JUAN MTNS
THROUGH EARLY EVENING. MEANWHILE...RAINFALL ASSOCIATED WITH THE
CENTER OF ROTATION ACROSS SRN UT WILL ALSO MOVE EAST. OBSERVED
RAINFALL RATES SO FAR THIS AFTERNOON HAVE BEEN 0.2 TO 0.3/HOUR IN
PARTS OF THE SAN JUANS AND IN THE CENTRAL MTNS. EXPECT EVEN HIGHER
RATES TO OCCUR WITH THE STRONG CONVECTION. SO FLASH FLOOD WATCH
LOOKS GOOD AND WILL REMAIN IN EFFECT THROUGH MIDNIGHT. THERE IS A
MID LEVEL SHEAR AXIS BASICALLY ALONG I-70 WITH DRIER AIR TO THE
NORTH. CONSEQUENTLY CONVECTION NORTH OF I-70 WILL BE LESS ROBUST.
EXPECT SHOWERS TO DIMINISH OVERNIGHT BUT LINGER OVER THE CENTRAL
AND SOUTHERN AREAS TO SOME EXTENT.
ON THURSDAY...THE SHORTWAVE SHOULD BE EAST OF THE AREA WITH THE
RIDGE AXIS AGAIN DOMINATING. HOWEVER...THERE WILL STILL BE MID TO
HIGH LEVEL MOISTURE TRAPPED UNDER THE RIDGE...SO EXPECT ISOLATED
TO SCATTERED CONVECTION DIURNAL CONVECTION WEST TO NUMEROUS STORMS
EAST...FOCUSED ON THE USUAL HIGHER TERRAIN LOCATIONS.
SLIGHTLY LESS CLOUD COVER INITIALLY ON THURSDAY WILL HELP TEMPS
RISE A LITTLE QUICKER AND HIGHER THAN TODAY...THOUGH STILL REMAIN
BELOW NORMAL.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 320 PM MDT WED AUG 7 2013
THE LARGE SCALE PATTERN CHANGES LITTLE AS A LOW PRESSURE TROUGH
CONTINUES TO SIT ALONG THE WEST COAST...AND HIGH PRESSURE REMAINS
PARKED OVER TEXAS. AFTER A BRIEF PERIOD OF NORTH/NORTHWEST FLOW
BEHIND TODAY`S DISTURBANCE...SOUTHERLY FLOW WILL QUICKLY BECOME
REESTABLISHED ON FRIDAY. HOWEVER MODELS CONTINUE TO ADVERTISE A
MODEST DROP IN MOISTURE ACROSS THE AREA. THESE SOMEWHAT DRIER
CONDITIONS WILL THEN PERSIST THROUGH THE EARLY PART OF NEXT WEEK.
PRECIPITABLE WATER WILL DROP FROM TODAY`S VALUES OF 0.6-1.0 INCH
...NORTH-SOUTH/CENTRAL TO MORE LIKE 0.4-0.6 INCH ACROSS MOST OF
THE AREA. THE LATEST MODEL RUNS HAVE DELAYED FURTHER DRYING UNTIL
AROUND MIDWEEK. BETTER SUNSHINE AND THIS MODEST AMOUNT OF MOISTURE
WILL STILL RESULT IN ISOLATED TO SCATTERED AFTERNOON SHOWER AND
THUNDERSTORM DEVELOPMENT...BUT THIS WILL GENERALLY BE TIED TO THE
HIGHER TERRAIN IN THIS DRIER ENVIRONMENT. ONE WEAK DISTURBANCE
WILL PASS ACROSS ID/WY AROUND THE TOP OF THE RIDGE ON FRIDAY FOR A
LITTLE ENHANCEMENT ACROSS THE NORTH...OTHERWISE THE SOUTH WILL BE
FAVORED.
THE 12Z GFS AND ECMWF RUNS SHOW GOOD AGREEMENT WITH THIS
PERSISTENT PATTERN...AND AS THE HIGH EVENTUALLY SHIFTS WEST INTO
SOUTHERN NM/AZ BY THE MIDDLE OF NEXT WEEK. AS THE HIGH REACHES
SOUTHERN NM...IT WILL TEND TO BLOCK THE SUBTROPICAL MOISTURE
STREAM. THEREFORE LOOK FOR ANOTHER NOTCH OF DRYING. IN SPITE OF
GOOD MODEL AGREEMENT...SUBSEQUENT MODEL RUNS HAVE SLOWED THE
DRYING TREND. THEREFORE CONFIDENCE IS NOT OVERLY HIGH.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1039 PM MDT WED AUG 7 2013
VFR CONDITIONS WILL PREVAIL AT THE TAFS SITES TONIGHT. AREAS OF
PRECIPITATION OVER SW CO AND SE UT WILL PRODUCE LOCAL MOUNTAIN
OBSCURATIONS. SCATTERED THUNDERSTORMS SHOULD FORM THURSDAY
AFTERNOON AND EVENING...MAINLY OVER THE MOUNTAINS. KASE...KRIL...
AND KEGE HAVE ABOUT AT 15 PERCENT CHANCE OF MVFR VSBYS IN STRONGER
RAIN SHOWERS. THE STORMS WILL CAUSE LOCAL MOUNTAINS OBSCURATIONS.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
UPDATE...CC
SHORT TERM...BWM
LONG TERM...EH
AVIATION...CC
AREA FORECAST DISCUSSION
NWS ALBANY NY
134 PM EDT THU AUG 8 2013
.SYNOPSIS...
AHEAD OF A SLOW MOVING COLD FRONT...A MUGGY AIR MASS IN PLACE WILL
ALLOW FOR SOME SHOWERS AND THUNDERSTORMS THIS AFTERNOON. AS THE
COLD FRONT MOVES ACROSS THE REGION...ADDITIONAL SHOWERS AND
THUNDERSTORMS...SOME WITH HEAVY RAINFALL...WILL OCCUR TONIGHT INTO
TOMORROW. DRIER AND LESS HUMID CONDITIONS WILL RETURN FOR THE
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 100 PM EDT...RADARS INDICATING STILL NO REAL CONVECTION HAS
DEVELOPED OVER THE AREA. THERE WERE PLENTY OF CU AND SOME HIGH
CLOUDS AND MSAS ANALYSIS INDICATED SURFACE BASED CAPES UP TO 1500
J/KG.
THE LATEST HRRR AND HIRES WRF MODELS CONTINUE TO INDICATE CONVECTION
WILL DEVELOP DURING THE AFTERNOON.
FORCING REMAINS WEAK BUT ANY WEAK BOUNDARIES INCLUDING A DEWPOINT
BOUNDARY WELL TO OUR WEST IN SW NY...AND EVEN TERRAIN ASPECT COULD
ALLOW FOR SOME CONVECTION TO DEVELOP LATER IN THE AFTERNOON. THERE
ARE BREAKS OF SUNSHINE...ALBEIT NOT MANY...THAT COULD HELP THE
CAUSE.
FOR THIS UPDATE...PUSHED BACK THE TIME OF DEVELOPMENT (LATER) AND
LOWERED POPS A TAD...GENERALLY HELD TO THE 30-50 PERCENT FOR LATE
AFTERNOON. THE 12Z ALY/MODEL SOUNDINGS DO INDICATE A DISTINCT MID
LEVEL DRY AREA THAT COULD ALLOW FOR MOMENTUM OF MODEST WINDS ALOFT
TO MIX DOWN...ALTHOUGH THEY ARE ONLY AROUND 40 KTS AROUND THE
20,000+ LEVEL. WILL LEAVE THEM IN
KEPT HIGH TEMPERATURES VERY SIMILAR TO BEFORE DESPITE THE FACT THAT
SOME AREAS WERE ALREADY APPROACHING HIGH TEMPERATURES. THE CLOUDS
SHOULD KEEP HIGH TEMPERATURES FROM RISING MUCH MORE. LOOK FOR HIGHS
WITHIN A FEW DEGREES OF 80. HOWEVER DEWPOINTS 65 TO 70 WILL ACTUALLY
MAKE THESE READINGS FEEL A TAD HIGHER.
SOME OF THE MORE SPECIFIC PARAMETERS AFFECTING CONVECTIVE MODE
THIS AFTERNOON AND EVENING ARE DESCRIBED IN THE PREVIOUS AFD
BELOW...
WITH SFC CAPE VALUES EXPECTED TO REACH AROUND 1000 J/KG...AND 500
HPA WINDS OF AROUND 25-30 KTS IN PLACE...THERE MAY BE JUST ENOUGH
INGREDIENTS IN PLACE FOR A FEW STRONG STORMS ACROSS OUR AREA.
WHILE WIDESPREAD SVR STORMS IS NOT ANTICIPATED...IT/S POSSIBLE
THAT A ROGUE STORM OR TWO COULD PRODUCE GUSTY WINDS...ESP
CONSIDERING INCREASING HIGH PWAT VALUES AROUND 1.50 INCHES
MAY ALLOW FOR A PRECIP LOADING INDUCED WIND GUST WITHIN ANY HEAVY
SHOWER OR THUNDERSTORM. SPC HAS PLACED OUR AREA IN A 5% PROB FOR SVR
WX...AND THIS LOOKS TO BE RIGHT. WE WILL MENTION THE POTENTIAL FOR
GUSTY WINDS IN THE ZONES AND HWO PRODUCT.
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
THE SFC FRONT WILL STALL CLOSE TO OR OVER OUR AREA TONIGHT INTO
FRIDAY WHILE THE UPPER LEVEL ENERGY SLOWLY BARRELS ACROSS ONTARIO.
A STRONG JET STREAK AT 250 HPA OF AROUND 125 KTS WILL UNDERCUT THE
UPPER LEVEL LOW AND BE SITUATED OVER THE UPPER GREAT LAKES AND
SOUTHERN CANADA. WITH THE UPSTREAM JET STREAK...HIGH MOISTURE IN
PLACE...AND PROXIMITY OF THE SFC BOUNDARY...SHOWERS AND
THUNDERSTORMS LOOK LIKELY TONIGHT INTO FRIDAY OVER MUCH OF THE
REGION. A WEAK SURFACE WAVE MAY DEVELOP ALONG THE BOUNDARY FOR
FRIDAY AS WELL...WHICH MAY HELP INCREASE COVERAGE OF
SHOWERS/STORMS...AS WELL AS HELP MOVE THE BOUNDARY SOUTHEAST
SOMEWHAT BY LATE IN THE DAY FRIDAY.
IT WILL BE DIFFICULT TO SAY EXACTLY WHERE AND WHEN
SHOWERS/TSTMS WILL TRACK THROUGH THE PERIOD. WITH THE CONVECTIVE
NATURE OF THE PRECIP...THERE IS THE POTENTIAL FOR QPF AMOUNTS TO
BE RATHER VARIABLE ACROSS THE REGION. HOWEVER WE CAN SAY WITH
CERTAINTY THAT WITH PWATS STILL AROUND TWO INCHES...HEAVY RAINFALL
WILL BE A POSSIBILITY WITH ANY SHOWER/STORM...AND WE WILL CONTINUE
TO MENTION THIS IN BOTH THE GRIDS AND HWO. SEE OUR HYDRO SECTION
ON HOW WE EXPECT THIS RAINFALL TO IMPACT THE HSA.
SIMILAR TO TODAY /THURS/...SPC HAS OUR REGION IN A /SEE TEXT/ FOR
STORMS ON FRIDAY WITH A 5% PROB FOR SVR IN PLACE. AGAIN...LIMITED
INSTABILITY AND WEAK LAPSE RATES WILL PREVENT WIDESPREAD SVR
WX...BUT ANY BREAKS IN THE CLOUDS WILL INCREASE THE THREAT FOR A
ROGUE STRONGER STORM.
MIN TEMPS TONIGHT WILL BE WARM AND MUGGY...WITH MID 60S TO LOW 70S
EXPECTED. MAX TEMPS ON FRIDAY WILL GENERALLY BE IN THE 70S TO NEAR
80.
THE FRONT WILL FINALLY START TO MOVE AWAY ON FRIDAY NIGHT. SOME
SHOWERS MAY LINGER ACROSS SOUTHEASTERN AREAS INTO FRIDAY
EVENING...BUT THE ENTIRE REGION SHOULD BE CLEARED OUT BY SAT
MORNING. MIN TEMPS ON FRI NIGHT WILL STILL BE IN THE 60S IN MOST
PLACES.
DRIER AND LESS HUMID CONDITIONS ARE EXPECTED SAT INTO SAT NIGHT AS
SFC HIGH PRESSURE BUILDS INTO THE REGION FROM THE GREAT LAKES. MAX
TEMPS ON SAT WILL BE IN THE 70S TO LOW 80S AND MIN TEMPS SAT NIGHT
WITH BE IN THE 40S AND 50S.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
MAINLY DRY WEATHER IS EXPECTED DURING THE LONG TERM PERIOD WITH ONLY
A CHANCE OF SHOWERS AND THUNDERSTORMS ON TUESDAY.
SUNDAY THROUGH MONDAY NIGHT...EXPECT DRY CONDITIONS AS A RIDGE OF
HIGH PRESSURE BUILDS ACROSS THE REGION AT THE SURFACE. EXPECT HIGHS
ON SUNDAY AND MONDAY TO RANGE FROM THE LOWER 70S NORTHWEST TO THE
LOWER 80S SOUTHEAST. LOWS SATURDAY NIGHT ARE EXPECTED TO RANGE FROM
THE LOWER 40S NORTHWEST TO MID 50S SOUTHEAST WITH LOWS SUNDAY NIGHT
RANGING FROM THE UPPER 40S NORTHWEST TO UPPER 50S SOUTHEAST AND LOWS
MONDAY NIGHT IN THE 50S TO LOWER 60S.
TUESDAY...A WEAK TROUGH OF LOW PRESSURE WILL SLIDE SOUTHEAST FROM
THE EASTERN GREAT LAKES AND SOUTHEAST CANADA. SCATTERED SHOWERS AND
THUNDERSTORMS ARE EXPECTED ALONG AND AHEAD OF THIS FEATURE WITH SB
CAPES RISING TO BTWN 500 AND 1000 J/KG HIGHS ON TUESDAY ARE EXPECTED
TO BE IN THE 70S TO AROUND 80 WITH A FEW AREAS ACROSS THE SRN
ADIRONDACKS IN THE UPPER 60S.
TUESDAY NIGHT AND WEDNESDAY...EXPECT A RETURN TO DRY CONDITIONS AS
HIGH PRESSURE BUILDS BACK INTO THE NORTHEAST. LOWS TUESDAY NIGHT ARE
EXPECTED TO RANGE FROM THE UPPER 40S NORTHWEST TO UPPER 50S
SOUTHEAST WITH HIGHS ON WEDNESDAY RANGING FROM THE UPPER 60S
NORTHWEST TO UPPER 70S SOUTHEAST.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
SOME ISOLATED SHOWERS AND THUNDERSTORMS ARE BEGINNING TO FORM IN
THE EASTERN CATSKILLS AND COULD TRACK TOWARD KPOU LATER THIS
AFTERNOON. OTHERWISE...VERY LITTLE ORGANIZED FORCING TO TRIGGER
SHOWERS AND THUNDERSTORMS IN OTHER AREAS THROUGH THIS
AFTERNOON...EVEN INTO EARLY THIS EVENING. THERE ARE SCATTERED
VARIABLE BROKEN CLOUDS NEAR AND ABOVE 3000 FEET ACROSS THE REGION
AND SOME ISOALTED TO SCATTERED SHOWERS AND THUNDERSTORMS COULD
FORM IN THE WESTERN MOHAWK VALLEY OR SOUTHERN ADIRONDACKS THAT
COULD TRACK TOWARD KALB...KGFL AND KPSF THIS EVENING. MORE
ORGANIZED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO TRACK INTO THE
REGION FROM THE GREAT LAKES OVERNIGHT INTO TOMORROW MORNING WITH
SOLID MVFR CEILINGS AND VISIBILITIES TONIGHT INTO TOMORROW...
POSSIBLY DROPPING INTO IFR. UNTIL CONFIDENCE IN IFR IS HIGHER...
KEEPING LOW MVFR TONIGHT AND TOMORROW MORNING WITH SHOWERS.
SOUTH TO SOUTHWEST WINDS AT 10 MPH OR LESS THIS AFTERNOON SHOULD
BECOMING LIGHT SOUTH TONIGHT AND THEN INCREASE AGAIN TO 6-10 KT
TOMORROW MORNING.
OUTLOOK...
THURSDAY NIGHT AND FRIDAY: HIGH OPERATIONAL IMPACT. LIKELY
SHRA...TSRA.
SATURDAY THROUGH MONDAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
NO FIRE WX ISSUES ARE ANTICIPATED OVER THE NEXT SEVERAL DAYS.
SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS THE REGION TODAY
THROUGH TOMORROW NIGHT. DRY WEATHER WILL RETURN OVER THE WEEKEND.
RH VALUES WILL ONLY DROP TO 65 PERCENT THIS AFTERNOON WITH
SOUTHERLY WINDS OF 5 TO 10 MPH. RH VALUES WILL RETURN TO NEAR 100
PERCENT TONIGHT WITH SOUTH WINDS AT 5 MPH. RH VALUES GENERALLY
GREATER THAN 70 PERCENT WILL BE IN PLACE FOR TOMORROW WITH RAIN
SHOWERS LIKELY.
&&
.HYDROLOGY...
SHOWERS AND THUNDERSTORMS WILL MOVE ACROSS THE REGION TODAY
THROUGH TOMORROW NIGHT AS A COLD FRONT MOVES ACROSS THE REGION.
THE MOST LIKELY PERIOD FOR SEEING RAINFALL WILL BE TONIGHT INTO
FRIDAY. AREAS SOUTH AND EAST OF THE CAPITAL REGION LOOK
TO SEE THE HEAVIEST RAINFALL...AS THE FRONTAL BOUNDARY WILL STALL
CLOSE TO THIS AREA...AND A WAVE OF LOW PRESSURE WILL MOVE ALONG
THE BOUNDARY.
WITH PWATS NEAR TWO INCHES AND DEWPOINTS IN THE MID 60S TO NEAR
70...HEAVY RAINFALL WILL BE POSSIBLE WITHIN ANY OF THE SHOWERS AND
THUNDERSTORMS. FFG VALUES LOOK TO BE AT TYPICAL VALUES FOR EARLY
AUGUST...AND IT WILL REQUIRE ABOUT TWO TO THREE INCHES OF RAINFALL
IN A ONE HOUR PERIOD TO CAUSE FLASH FLOODING. DEPENDING ON WHERE
SHOWERS AND THUNDERSTORMS TRACK...MINOR FLOODING OF URBAN...POOR
DRAINAGE...AND LOW LYING AREAS WILL BE POSSIBLE THROUGH
FRIDAY...MAINLY FOR AREAS SOUTH AND EAST OF THE CAPITAL REGION.
DRIER WEATHER WILL RETURN TO THE REGION OVER THE WEEKEND. WHILE
THERE MAY BE SOME IN BANKS RISES ON MAIN STEM RIVERS AND STREAMS LATE
THIS WEEK...DRY WEATHER OVER THE WEEKEND WILL ALLOW THESE FLOWS TO
RECEDE.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS/NAS
NEAR TERM...HWJIV/NAS
SHORT TERM...FRUGIS
LONG TERM...11
AVIATION...NAS
FIRE WEATHER...FRUGIS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS ALBANY NY
100 PM EDT THU AUG 8 2013
.SYNOPSIS...
AHEAD OF A SLOW MOVING COLD FRONT...A MUGGY AIR MASS IN PLACE WILL
ALLOW FOR SOME SHOWERS AND THUNDERSTORMS THIS AFTERNOON. AS THE
COLD FRONT MOVES ACROSS THE REGION...ADDITIONAL SHOWERS AND
THUNDERSTORMS...SOME WITH HEAVY RAINFALL...WILL OCCUR TONIGHT INTO
TOMORROW. DRIER AND LESS HUMID CONDITIONS WILL RETURN FOR THE
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 100 PM EDT...RADARS INDICATING STILL NO REAL CONVECTION HAS
DEVELOPED OVER THE AREA. THERE WERE PLENTY OF CU AND SOME HIGH
CLOUDS AND MSAS ANALYSIS INDICATED SURFACE BASED CAPES UP TO 1500
J/KG.
THE LATEST HRRR AND HIRES WRF MODELS CONTINUE TO INDICATE CONVECTION
WILL DEVELOP DURING THE AFTERNOON.
FORCING REMAINS WEAK BUT ANY WEAK BOUNDARIES INCLUDING A DEWPOINT
BOUNDARY WELL TO OUR WEST IN SW NY...AND EVEN TERRAIN ASPECT COULD
ALLOW FOR SOME CONVECTION TO DEVELOP LATER IN THE AFTERNOON. THERE
ARE BREAKS OF SUNSHINE...ALBEIT NOT MANY...THAT COULD HELP THE
CAUSE.
FOR THIS UPDATE...PUSHED BACK THE TIME OF DEVELOPMENT (LATER) AND
LOWERED POPS A TAD...GENERALLY HELD TO THE 30-50 PERCENT FOR LATE
AFTERNOON. THE 12Z ALY/MODEL SOUNDINGS DO INDICATE A DISTINCT MID
LEVEL DRY AREA THAT COULD ALLOW FOR MOMENTUM OF MODEST WINDS ALOFT
TO MIX DOWN...ALTHOUGH THEY ARE ONLY AROUND 40 KTS AROUND THE
20,000+ LEVEL. WILL LEAVE THEM IN
KEPT HIGH TEMPERATURES VERY SIMILAR TO BEFORE DESPITE THE FACT THAT
SOME AREAS WERE ALREADY APPROACHING HIGH TEMPERATURES. THE CLOUDS
SHOULD KEEP HIGH TEMPERATURES FROM RISING MUCH MORE. LOOK FOR HIGHS
WITHIN A FEW DEGREES OF 80. HOWEVER DEWPOINTS 65 TO 70 WILL ACTUALLY
MAKE THESE READINGS FEEL A TAD HIGHER.
SOME OF THE MORE SPECIFIC PARAMETERS AFFECTING CONVECTIVE MODE
THIS AFTERNOON AND EVENING ARE DESCRIBED IN THE PREVIOUS AFD
BELOW...
WITH SFC CAPE VALUES EXPECTED TO REACH AROUND 1000 J/KG...AND 500
HPA WINDS OF AROUND 25-30 KTS IN PLACE...THERE MAY BE JUST ENOUGH
INGREDIENTS IN PLACE FOR A FEW STRONG STORMS ACROSS OUR AREA.
WHILE WIDESPREAD SVR STORMS IS NOT ANTICIPATED...IT/S POSSIBLE
THAT A ROGUE STORM OR TWO COULD PRODUCE GUSTY WINDS...ESP
CONSIDERING INCREASING HIGH PWAT VALUES AROUND 1.50 INCHES
MAY ALLOW FOR A PRECIP LOADING INDUCED WIND GUST WITHIN ANY HEAVY
SHOWER OR THUNDERSTORM. SPC HAS PLACED OUR AREA IN A 5% PROB FOR SVR
WX...AND THIS LOOKS TO BE RIGHT. WE WILL MENTION THE POTENTIAL FOR
GUSTY WINDS IN THE ZONES AND HWO PRODUCT.
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
THE SFC FRONT WILL STALL CLOSE TO OR OVER OUR AREA TONIGHT INTO
FRIDAY WHILE THE UPPER LEVEL ENERGY SLOWLY BARRELS ACROSS ONTARIO.
A STRONG JET STREAK AT 250 HPA OF AROUND 125 KTS WILL UNDERCUT THE
UPPER LEVEL LOW AND BE SITUATED OVER THE UPPER GREAT LAKES AND
SOUTHERN CANADA. WITH THE UPSTREAM JET STREAK...HIGH MOISTURE IN
PLACE...AND PROXIMITY OF THE SFC BOUNDARY...SHOWERS AND
THUNDERSTORMS LOOK LIKELY TONIGHT INTO FRIDAY OVER MUCH OF THE
REGION. A WEAK SURFACE WAVE MAY DEVELOP ALONG THE BOUNDARY FOR
FRIDAY AS WELL...WHICH MAY HELP INCREASE COVERAGE OF
SHOWERS/STORMS...AS WELL AS HELP MOVE THE BOUNDARY SOUTHEAST
SOMEWHAT BY LATE IN THE DAY FRIDAY.
IT WILL BE DIFFICULT TO SAY EXACTLY WHERE AND WHEN
SHOWERS/TSTMS WILL TRACK THROUGH THE PERIOD. WITH THE CONVECTIVE
NATURE OF THE PRECIP...THERE IS THE POTENTIAL FOR QPF AMOUNTS TO
BE RATHER VARIABLE ACROSS THE REGION. HOWEVER WE CAN SAY WITH
CERTAINTY THAT WITH PWATS STILL AROUND TWO INCHES...HEAVY RAINFALL
WILL BE A POSSIBILITY WITH ANY SHOWER/STORM...AND WE WILL CONTINUE
TO MENTION THIS IN BOTH THE GRIDS AND HWO. SEE OUR HYDRO SECTION
ON HOW WE EXPECT THIS RAINFALL TO IMPACT THE HSA.
SIMILAR TO TODAY /THURS/...SPC HAS OUR REGION IN A /SEE TEXT/ FOR
STORMS ON FRIDAY WITH A 5% PROB FOR SVR IN PLACE. AGAIN...LIMITED
INSTABILITY AND WEAK LAPSE RATES WILL PREVENT WIDESPREAD SVR
WX...BUT ANY BREAKS IN THE CLOUDS WILL INCREASE THE THREAT FOR A
ROGUE STRONGER STORM.
MIN TEMPS TONIGHT WILL BE WARM AND MUGGY...WITH MID 60S TO LOW 70S
EXPECTED. MAX TEMPS ON FRIDAY WILL GENERALLY BE IN THE 70S TO NEAR
80.
THE FRONT WILL FINALLY START TO MOVE AWAY ON FRIDAY NIGHT. SOME
SHOWERS MAY LINGER ACROSS SOUTHEASTERN AREAS INTO FRIDAY
EVENING...BUT THE ENTIRE REGION SHOULD BE CLEARED OUT BY SAT
MORNING. MIN TEMPS ON FRI NIGHT WILL STILL BE IN THE 60S IN MOST
PLACES.
DRIER AND LESS HUMID CONDITIONS ARE EXPECTED SAT INTO SAT NIGHT AS
SFC HIGH PRESSURE BUILDS INTO THE REGION FROM THE GREAT LAKES. MAX
TEMPS ON SAT WILL BE IN THE 70S TO LOW 80S AND MIN TEMPS SAT NIGHT
WITH BE IN THE 40S AND 50S.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
MAINLY DRY WEATHER IS EXPECTED DURING THE LONG TERM PERIOD WITH ONLY
A CHANCE OF SHOWERS AND THUNDERSTORMS ON TUESDAY.
SUNDAY THROUGH MONDAY NIGHT...EXPECT DRY CONDITIONS AS A RIDGE OF
HIGH PRESSURE BUILDS ACROSS THE REGION AT THE SURFACE. EXPECT HIGHS
ON SUNDAY AND MONDAY TO RANGE FROM THE LOWER 70S NORTHWEST TO THE
LOWER 80S SOUTHEAST. LOWS SATURDAY NIGHT ARE EXPECTED TO RANGE FROM
THE LOWER 40S NORTHWEST TO MID 50S SOUTHEAST WITH LOWS SUNDAY NIGHT
RANGING FROM THE UPPER 40S NORTHWEST TO UPPER 50S SOUTHEAST AND LOWS
MONDAY NIGHT IN THE 50S TO LOWER 60S.
TUESDAY...A WEAK TROUGH OF LOW PRESSURE WILL SLIDE SOUTHEAST FROM
THE EASTERN GREAT LAKES AND SOUTHEAST CANADA. SCATTERED SHOWERS AND
THUNDERSTORMS ARE EXPECTED ALONG AND AHEAD OF THIS FEATURE WITH SB
CAPES RISING TO BTWN 500 AND 1000 J/KG HIGHS ON TUESDAY ARE EXPECTED
TO BE IN THE 70S TO AROUND 80 WITH A FEW AREAS ACROSS THE SRN
ADIRONDACKS IN THE UPPER 60S.
TUESDAY NIGHT AND WEDNESDAY...EXPECT A RETURN TO DRY CONDITIONS AS
HIGH PRESSURE BUILDS BACK INTO THE NORTHEAST. LOWS TUESDAY NIGHT ARE
EXPECTED TO RANGE FROM THE UPPER 40S NORTHWEST TO UPPER 50S
SOUTHEAST WITH HIGHS ON WEDNESDAY RANGING FROM THE UPPER 60S
NORTHWEST TO UPPER 70S SOUTHEAST.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
EARLY THIS MORNING EXPECT MAINLY VFR VSBYS AND VFR/MVFR CIGS WHICH
WILL GIVE WAY TO ENTIRELY VFR CONDITIONS AFT 14Z. HAVE PLACED VCSH
IN THE TAFS AFT 14Z AS CONVECTION TO THE WEST MOVES EAST INTO THE
HUDSON VALLEY. THE BIG QUESTION WILL BE HOW MUCH OF THIS PCPN HOLDS
TOGETHER AS IT MOVES INTO A SLIGHTLY MORE STABLE AIRMASS. THIS
AFTERNOON THROUGH THIS EVENING LOOKS TO HAVE A BETTER CHANCE OF
CONVECTION AND MORE WIDESPREAD SHOWER ACTIVITY IS EXPECTED LATE
TONIGHT AFT 09Z WITH MAINLY MVFR CONDITIONS.
WINDS SHOULD BE SOUTH TO SOUTHWEST AT 6-10 KTS WITH GUSTS TO 16 KTS
AT KALB. WINDS WILL DIMINISH TONIGHT TO LESS THAN 6 KTS EXCEPT AT
KALB WHERE SOUTH WINDS WILL REMAIN AT 8-10 KTS.
OUTLOOK...
THURSDAY NIGHT AND FRIDAY: HIGH OPERATIONAL IMPACT. LIKELY
SHRA...TSRA.
SATURDAY THROUGH MONDAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
NO FIRE WX ISSUES ARE ANTICIPATED OVER THE NEXT SEVERAL DAYS.
SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS THE REGION TODAY
THROUGH TOMORROW NIGHT. DRY WEATHER WILL RETURN OVER THE WEEKEND.
RH VALUES WILL ONLY DROP TO 65 PERCENT THIS AFTERNOON WITH
SOUTHERLY WINDS OF 5 TO 10 MPH. RH VALUES WILL RETURN TO NEAR 100
PERCENT TONIGHT WITH SOUTH WINDS AT 5 MPH. RH VALUES GENERALLY
GREATER THAN 70 PERCENT WILL BE IN PLACE FOR TOMORROW WITH RAIN
SHOWERS LIKELY.
&&
.HYDROLOGY...
SHOWERS AND THUNDERSTORMS WILL MOVE ACROSS THE REGION TODAY
THROUGH TOMORROW NIGHT AS A COLD FRONT MOVES ACROSS THE REGION.
THE MOST LIKELY PERIOD FOR SEEING RAINFALL WILL BE TONIGHT INTO
FRIDAY. AREAS SOUTH AND EAST OF THE CAPITAL REGION LOOK
TO SEE THE HEAVIEST RAINFALL...AS THE FRONTAL BOUNDARY WILL STALL
CLOSE TO THIS AREA...AND A WAVE OF LOW PRESSURE WILL MOVE ALONG
THE BOUNDARY.
WITH PWATS NEAR TWO INCHES AND DEWPOINTS IN THE MID 60S TO NEAR
70...HEAVY RAINFALL WILL BE POSSIBLE WITHIN ANY OF THE SHOWERS AND
THUNDERSTORMS. FFG VALUES LOOK TO BE AT TYPICAL VALUES FOR EARLY
AUGUST...AND IT WILL REQUIRE ABOUT TWO TO THREE INCHES OF RAINFALL
IN A ONE HOUR PERIOD TO CAUSE FLASH FLOODING. DEPENDING ON WHERE
SHOWERS AND THUNDERSTORMS TRACK...MINOR FLOODING OF URBAN...POOR
DRAINAGE...AND LOW LYING AREAS WILL BE POSSIBLE THROUGH
FRIDAY...MAINLY FOR AREAS SOUTH AND EAST OF THE CAPITAL REGION.
DRIER WEATHER WILL RETURN TO THE REGION OVER THE WEEKEND. WHILE
THERE MAY BE SOME IN BANKS RISES ON MAIN STEM RIVERS AND STREAMS LATE
THIS WEEK...DRY WEATHER OVER THE WEEKEND WILL ALLOW THESE FLOWS TO
RECEDE.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS/NAS
NEAR TERM...HWJIV/NAS/FRUGIS
SHORT TERM...FRUGIS
LONG TERM...11
AVIATION...11
FIRE WEATHER...FRUGIS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1030 AM EDT THU AUG 8 2013
.SYNOPSIS...
SHOWERS AND HUMIDITY WILL INCREASE TODAY AS A WEAK WARM FRONT
MOVES NORTH OF THE REGION. A COLD FRONT WILL SHIFT SLOWLY INTO
NEW ENGLAND THURSDAY AND FRIDAY BRINGING SHOWERS AND
THUNDERSTORMS...SOME WITH HEAVY RAINFALL. THIS FRONT WILL FINALLY
PUSH OFF THE COAST SATURDAY. HIGH PRESSURE BUILDS OVER THE REGION
SUNDAY AND MONDAY. ANOTHER COLD FRONT BRINGS SHOWERS ON TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1030 AM UPDATE...
MORNING ACTIVITY LOCALIZED ALONG THE H85 DEWPOINT GRADIENT AND
ATTENDANT LOW- TO MID-LEVEL WARM FRONT PRESSING EAST THRU THE GULF
OF MAINE DRAPING SOUTHWESTWARD TOWARDS NANTUCKET. AS SEEN PER
WSR-88D RETURNS...RAIN DIMINISHING ACROSS THE SOUTHEAST OUTER
WATERS. WILL CONTINUE CHANCE POPS ALONG THE DEWPOINT GRADIENT THRU
THE DAY WITH SLIGHT CHANCE POPS EAST OF THERE WITHIN THE MORE
DRIER AIR.
FOCUSING BACK ON THE INTERIOR...ENTRENCHING INTO THE WARM-MOIST
SECTOR AS THE SURFACE WARM FRONT ACROSS THE NORTHERN HUDSON RIVER
VALLEY DRAPED SOUTH THROUGH WESTERN AND CENTRAL PORTIONS OF NEW
ENGLAND SLOWLY PUSHES EAST AGAINST OFFSHORE HIGH PRESSURE AND
DRIER AIR. MODEST SURFACE-H85 SOUTHWEST MOISTURE TRANSPORT PUSHING
UPPER 60S INTO 70S DEWPOINTS INTO NEW ENGLAND /RETURN OF MUGGY
CONDITION/ RESULTING IN PWATS GETTING UP TO 2 INCHES.
SO WE HAVE THE MOISTURE...NOW ITS A QUESTION OF DESTABILIZATION.
BUT A CAVEAT. 12Z ALBANY SOUNDING AND RAP MESOANALYSIS SHOWS A DRY
POCKET OF AIR ACROSS THE CENTRAL TO LOWER HUDSON RIVER VALLEY.
EARLIER LINE OF STORMS ACROSS UPSTATE NY INTO NORTHERN PA HAS RUN
INTO THIS AIRMASS AND DIMINISHED ENTIRELY. RAP FORECAST GUIDANCE
HAS THIS AIRMASS MOVING EAST INTO NEW ENGLAND DURING THE DAY
RESULTING IN THE POSSIBILITY OF LITTLE TO NO ACTIVITY. ADDITIONAL
GUIDANCE IS FAIRLY QUIET AS WELL WITH THE WRF-ARW THE MOST ROBUST.
CONSIDERING THE 12Z SOUNDING OUT OF BUFFALO WHICH LOOKS MORE
FAVORABLE FOR THUNDERSTORM DEVELOPMENT...FEEL THIS AIRMASS WILL
PUSH EAST INTO THE HUDSON VALLEY DURING THE DAY. FACTORING IN
SUNSHINE AND A DESTABILIZING BOUNDARY LAYER...EXPECT MLCAPE
INSTABILITY UP TO 2K J/KG SHOULD BE UTILIZED. USING A THRESHOLD OF
SURFACE LIFTED INDICES OF -4C...HAVE DEFINED WHERE THERE IS A
BETTER CHANCE OF THUNDERSTORMS WHICH IS MAINLY ACROSS WESTERN AND
CENTRAL PORTIONS OF NEW ENGLAND.
WILL KEEP POPS AT CHANCE. WILL NOT MENTION ANY THREATS TILL
ACTIVITY DEVELOPS DUE TO CONTINUED UNCERTAINTY. MID-LEVEL LAPSE
RATES ARE POOR. BULK SHEAR IS WEAK WHILE UNI-DIRECTIONAL. SO ANY
THREATS LOOK TO BE POSSIBLE WIND DAMAGE WITH HEAVY RAIN AND
NUISANCE FLOODING. HAVE A FEELING TODAY MAY NOT MATERIALIZE INTO
MUCH THAN SCATTERED ACTIVITY WEST THAT REMAINS FAIRLY WEAK.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
TONIGHT AND FRIDAY...
SEVERAL MEMBERS OF THE MODEL SUITE...NAMELY THE 00Z GFS AND 12Z
ECMWF ALONG WITH THEIR ENSEMBLES APPEAR TO HAVE A GOOD HANDLE ON
THE EVOLUTION OF THE SLOW MOVING COLD FRONT ACROSS THE REGION. H5
WINDS WITH THE UPPER TROUGH BACK TO SW...WHICH WILL ALLOW DEEP
MOISTURE PLUME TO MOVE ACROSS THE REGION. EXPECT SHOWERS AND
THUNDERSTORMS TO PRODUCE LOCALLY HEAVY RAINFALL DURING THIS
TIMEFRAME. MORE DETAILS IN THE HYDRO SECTION BELOW.
FRIDAY COULD BE INTERESTING WITH SOME OF THE THUNDERSTORMS. MIXED
LAYER CAPE VALUES FORECAST TO 1000-1500 J/KG DURING THE AFTERNOON
AHEAD OF THE FRONT...ALONG WITH A WEAK MID LEVEL DISTURBANCE MOVING
ACROSS THE REGION. ALSO FAIRLY GOOD SHEAR IN PLACE WITH SW WINDS
AROUND 30 KT. THIS MAY PRODUCE SOME LOCALLY GUSTY WINDS IN ANY
STRONGER THUNDERSTORMS. WILL NEED TO MONITOR THIS FOR POSSIBILITY
OF LOCALLY DAMAGING WINDS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
BIG PICTURE/PREFERENCES...
SUBTROPICAL RIDGE HOLDS ACROSS THE SOUTHERN USA AND BUILDS OVER
THE ROCKIES INTO WESTERN CANADA. CLOSED UPPER LOW EJECTS THROUGH
EASTERN CANADA FRIDAY-SATURDAY. A SHORTWAVE FROM THE CANADIAN
ARCTIC THEN DROPS SOUTH THROUGH HUDSON BAY...MAINTAINING AND
POSSIBLY DEEPENING THE UPPER TROUGH OVER EASTERN CANADA/NORTHEAST
USA DURING THE FIRST HALF OF NEXT WEEK. THERMAL FIELDS SHOW
COOLING ALOFT OVER THE WEEKEND AND EARLY NEXT WEEK. THE ECMWF
SHOWS A COUPLE OF DEGREES MORE COOLING THAN THE GFS.
OUR MAIN PREFERENCE WAS HPC/WPC GRIDS WHERE AVAILABLE...A BLEND OF
GFS/ECMWF GRIDS OTHERWISE.
THE DAILIES...
FRIDAY NIGHT-SATURDAY...
A COLD FRONT MOVES THROUGH THE REGION OVERNIGHT. THIS IS DRIVEN
BY THE UPPER LOW PASSING NORTH OF NEW ENGLAND. THERE IS SOME
VARIATION IN THE PLACEMENT OF THE COLD FRONT FRIDAY EVENING...BUT
THE 00Z ECMWF AND GENERAL CONSENSUS CENTER ON THE HUDSON VALLEY.
SUFFICIENT LIFT/INSTABILITY AND PRECIPITABLE WATER VALUES 2 INCHES
OR HIGHER ALL POINT TO SHOWERS/TSTMS LEADING THE FRONT. COVERAGE
MAY NOT BE 100 PERCENT AS IS NORMAL FOR SHOWERS...BUT STRONG
CONFIDENCE IN OCCURRENCE. DEEP MOISTURE/HIGH PW VALUES SUGGEST
HEAVY DOWNPOURS WITH POTENTIAL FOR URBAN/POOR DRAINAGE FLOODING. A
FLASH FLOOD WATCH MAY BE NEEDED IN THE NEAR FUTURE TO COVER THIS
PRE-FRONTAL WEATHER. THE COLD FRONT SWEEPS ACROSS SOUTHERN NEW
ENGLAND DURING THE NIGHT WITH SHOWERS TAPERING OFF WITH FRONTAL
PASSAGE AND THE WIND SHIFT TO NORTHWEST. HIGH DEWPOINTS IN THE
EVENING...BUT LOWERING AFTER FROPA OVERNIGHT.
COULD BE SOME LINGERING CLOUDS/SHOWERS ALONG THE EAST AND SOUTH
COASTS SATURDAY MORNING BUT THE OVERALL TREND WILL BE FOR CLEARING
AND DIMINISHING HUMIDITY. MIXING SHOULD REACH TO AT LEAST 850 MB
AND POSSIBLY HIGHER. TEMPS AT THE TOP OF THE MIXED LAYER SHOULD
REACH 12-15C...WHICH WOULD ALLOW MAX TEMPS IN THE LOW TO MID 80S. A
MILD START COULD ADD A COUPLE OF DEGREES TO THE HIGH SIDE OF THIS
RANGE. WINDS AT THE TOP OF THIS MIXED LAYER WILL REACH AROUND 20
KNOTS...SO WE ARE FORECASTING A POTENTIAL FOR AFTERNOON GUSTS 20-25
MPH.
SUNDAY-MONDAY...
HIGH PRESSURE BUILDS OVER THE EAST AND SHOULD PROVIDE DRY
SEASONABLE WEATHER BOTH DAYS. SHORTWAVE MOVING ALONG THE CANADIAN
BORDER MAY BRING SOME COOLING ALOFT SUNDAY AND DESTABILIZE THE
AIRMASS FOR SOME DIURNAL CUMULUS. DEWPOINTS IN THE 50S AND LIGHT
WINDS WILL ALLOW EARLY MORNING LOWS IN THE 50S AND LOWER 60S EACH
DAY. TEMPS AT THE TOP OF THE MIXED LAYER WILL SUPPORT MAX TEMPS
AROUND 80 SUNDAY AND 80-85 MONDAY. IF MIXING GOES A LITTLE DEEPER
THAN FORECAST THEN WE MAY GET A COUPLE OF DEGREES WARMER.
TUESDAY...
SHORTWAVE DROPPING SOUTH TO THE GREAT LAKES MONDAY WILL SWING
EAST AND DRIVE PAST NORTHERN NEW ENGLAND TUESDAY. THIS WILL BRING
A COLD FRONT THROUGH THE REGION WHICH MAY GENERATE A FEW
SHOWERS/TSTMS. PW VALUES CLIMB ABOVE 1.5 INCHES WITH THE 2 INCH
CONTOUR LURKING JUST TO OUR SOUTH. SO HEAVY DOWNPOURS MAY AGAIN BE
A CONCERN.
WEDNESDAY...
THE NEXT HIGH PRESSURE AREA MOVES IN WITH DRY SEASONABLE AIR.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW THROUGH FRIDAY...HIGH CONFIDENCE IN TRENDS...LOW CONFIDENCE
IN TIMING.
TODAY...EXPECT MVFR-IFR CIGS ACROSS MOST AREAS WHICH SHOULD
IMPROVE TO VFR BY AFTERNOON. VSBYS MAINLY VFR...THOUGH WILL SEE
LOCAL MVFR-IFR VSBYS IN SHOWERS AND ISOLD TSTMS OFF AND ON
THROUGH THE DAY.
TONIGHT AND FRIDAY...EXPECT CIGS/VSBYS TO LOWER TO MVFR-IFR IN
LOW CLOUDS...PATCHY FOG AND SHOWERS/TSTMS. WILL SEE LOCALLY HEAVY
RAINFALL WHICH WILL ALSO LOWER VSBYS. MAY SEE SLOWLY IMPROVING
CONDITIONS LATE FRIDAY ACROSS SW NH/W MA...DEPENDING UPON THE
TIMING OF THE COLD FRONT.
KBOS TERMINAL...HIGH CONFIDENCE IN TRENDS...LOW CONFIDENCE IN
TIMING.
KBDL TERMINAL...HIGH CONFIDENCE IN TRENDS...LOW CONFIDENCE IN
TIMING.
OUTLOOK...FRIDAY NIGHT THROUGH MONDAY...
FRIDAY NIGHT... LOW CIGS AND POOR VSBYS IN SHOWERS/TSTMS AND AREAS
OF FOG. LOCALLY HEAVY DOWNPOURS ARE EXPECTED WITH POTENTIAL FOR POOR
DRAINAGE FLOODING. THE COLD FRONT SHOULD CROSS THE CT VALLEY AROUND
OR JUST AFTER SUNSET...AND REACH THE COASTAL AREAS AROUND MIDNIGHT
OR A LITTLE LATER. EXPECT SHOWERS TO TAPER OFF AFTER THE FRONT MOVES
THROUGH. LOCALLY LOW CIGS/VSBY POSSIBLE OVERNIGHT IN FOG.
SATURDAY-SUNDAY-MONDAY... VFR THROUGH THE PERIOD. NORTHWEST WINDS
SATURDAY MAY GUST TO 25 KNOTS DURING THE AFTERNOON AS DAYTIME
HEATING DRAWS THE STRONGER WINDS LOWER FROM HIGH ALTITUDES.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
TODAY THROUGH FRIDAY...HIGH CONFIDENCE.
TODAY AND TONIGHT...EXPECT S WINDS TO PICK UP DURING THE DAY WITH
AN INCREASING S SWELL. WINDS AND SEAS REMAIN BELOW SMALL CRAFT
CRITERIA. SHOWERS/SCT TSTMS EXPECTED WITH REDUCED VSBYS. MAY SEE
HEAVY DOWNPOURS IN SOME SHOWERS AND STORMS TONIGHT. PATCHY FOG
DEVELOPS TONIGHT WITH VSBYS 1-3NM.
FRIDAY...SW WINDS PICK UP DURING THE LATE MORNING AND AFTERNOON...
GUSTING TO 25 KT ON THE OPEN WATERS. SEAS ALSO INCREASE...UP TO 5-6
FT...HIGHEST ON THE SOUTHERN OUTER WATERS. DECIDED TO HOLD OFF ON
PUTTING SMALL CRAFT UP FOR NOW. WILL SEE SHOWERS/TSTMS WHICH MAY
PRODUCE HEAVY DOWNPOURS AND BRIEF GUSTY WINDS. PATCHY FOG AGAIN
REDUCING VSBYS.
OUTLOOK...FRIDAY NIGHT INTO MONDAY...
MODERATE CONFIDENCE.
FRIDAY NIGHT...
SHOWERS/TSTMS MOVE THROUGH DURING THE FIRST PART OF THE NIGHT. A
COLD FRONT WILL MOVE ACROSS THE WATERS LATER IN THE NIGHT WITH
SHOWERS ENDING AND WINDS SHIFTING TO NORTHWEST. SEAS WILL REMAIN
AROUND 5-6 FEET ON THE EXPOSED WATERS UNTIL THE WIND SHIFT AND
THEN DIMINISH. SMALL CRAFT ADVISORY WILL BE LIKELY FOR THESE
AREAS.
SATURDAY THROUGH MONDAY...
WINDS AND SEAS BELOW SMALL CRAFT THRESHOLDS DURING THIS PERIOD.
&&
.HYDROLOGY...
INCREASING LOW LEVEL MOISTURE FEED WILL MOVE INTO THE REGION LATE
TONIGHT AND FRIDAY ALONG A SLOW MOVING COLD FRONT. THE FRONT MAY
STALL FOR A TIME DURING FRIDAY...ALLOWING FOR TRAINING OF PRECIP
ACROSS THE REGION. EXPECT PWATS TO INCREASE TO 2 TO 2.25 INCHES
LATE TONIGHT AND FRIDAY. THIS...ALONG WITH THE INCREASING MOISTURE
CONVERGENCE AND SLOW MOVEMENT OF THE FRONT WILL BRING LOCALLY
HEAVY RAINFALL WITH THE SHOWERS/TSTMS AHEAD OF THE FRONT. QPF
AMOUNTS FORECAST TO BE A GENERAL 1-2 INCHES...BUT COULD SEE
LOCALLY HIGHER AMOUNTS IN HEAVIER PRECIP. HOWEVER...THE LOCATION
AND TIMING OF HEAVIEST RAINS REMAINS IN QUESTION.
MAIN THREAT WILL BE MINOR URBAN AND POOR DRAINAGE FLOODING...BUT
FLASH FLOODING IS POSSIBLE WITH ANY TRAINING CONVECTION. FLASHY
SMALL STREAM FLOODING COULD BECOME A CONCERN IF SEVERAL ROUNDS OF
CONVECTION OCCUR OVER THE SAME BASINS. THIS ASPECT WILL NEED TO
BE MONITORED CLOSELY...AND A FLASH FLOOD WATCH MAY NEED TO BE
ISSUED.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...WTB/EVT
NEAR TERM...SIPPRELL
SHORT TERM...EVT
LONG TERM...WTB
AVIATION...WTB/EVT
MARINE...WTB/EVT
HYDROLOGY...WFO BOX STAFF
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
117 PM EDT THU AUG 8 2013
.SYNOPSIS...
LOW PRESSURE MOVING ACROSS SOUTHEASTERN CANADA WILL ALLOW A COLD
FRONT TO APPROACH THE REGION ON FRIDAY AND CROSS THE AREA BY LATE
FRIDAY OR EARLY SATURDAY. THIS FRONT WILL EVENTUALLY STALL TO OUR
SOUTH FOR SUNDAY. EARLY NEXT WEEK, A FEW WAVES OF LOW PRESSURE ARE
FORECAST TO MOVE ALONG THE STALLED BOUNDARY. HIGH PRESSURE WILL
THEN BUILD IN TOWARD MIDWEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NOT A CONFIDENT ESTF UPDATE. WE HAVE DECIDED TO COMPROMISE BETWEEN
PREVIOUS FCST AND CURRENT SUGGESTIONS BY THE HRRR AND COSPA. WE
ARE SEEING A SHORT WAVE EMERGE FROM WV AND COUPLED WITH CONVECTIVE
TEMPERATURES BEING REACHED BELIEVE THIS SHOULD START TRIGGERING
AND ENHANCING CONVECTION AS WE MOVE FORWARD. THE PREVIOUS MCS HAS
LEFT A RELATIVELY STABLE POOL NW OF OUR CWA FOR NOW. SO THE
ADJUSTMENTS GOING FORWARD WERE TO LOWER POPS INITIALLY NORTHWEST
AND GIVE THAT SHORT WAVE A BIT MORE CREDIT AND INCREASE POPS IN
THE CENTRAL THIRD OF OUR CWA FOR THIS AFTERNOON. WE DID SEE A
NOTICEABLE DROP OFF IN 925MB OR 850MB MOISTURE OFF THE WALLOPS
SOUNDING THIS MORNING, SO CHANCES WERE KEPT IN THE SERN PART OF
OUR CWA. WE ARE WARMING AT 700MB AND 500MB, SO WITH BULK SHEAR
VALUES BEST NORTH AS WELL AS FORECAST TT(S), WE KEPT THE SOMEWHAT
ENHANCED WORDING TIED TO LIKELY POPS. THE FCST DCAPES ARE NOT
IMPRESSIVE AND NEITHER ARE THETA E DROP WITH HEIGHT, SO ANY STRONG
TO SEVERE ARE GOING TO HAVE TO BE TIED TO SOME RELATIVELY STRONGER
UPDRAFTS OR IF AN EFFECTIVE COOL POOL CAN FORM. THE LATTER DOES
NOT LOOK PROMISING. WE HAVE NOT HAD MANY DRY STRETCHES THIS
SUMMER, BUT THE RELATIVE LACK OF FLOODING RAINS LAST SEVERAL DAYS
HAS PERMITTED FFG AND FFH GUIDANCE TO GET CLOSER TO NORMAL SUMMER
VALUES. SO WHILE A FFW MIGHT STILL OCCUR, THIS WOULD SEEM TO BE
MORE OF AN ISOLATED OCCURRENCE.
12Z SOUNDINGS GIVE 90F AS A POSSIBLE HIGH SOUTHERN PART OF OUR
CWA (CONVECTIVE TEMP LOW 80S), SO BUMPED MAX TEMPS UPWARD IN
DELMARVA, KEPT THE REST RELATIVELY THE SAME.
UPPER HEIGHTS WILL BE RISING THRU THE DAY AND THERE ARE ONLY WEAK
S/W MOVING THRU THE FLOW. BREAKS WILL OCCUR TODAY ALLOWING FOR
POCKETS OF HEATING/INSTABILITY TO DEVELOP. WE WILL GO ALONG WITH THE
DETERMINISTIC MODELS AND MOS AND MOSTLY KEEP THE HIGHER CHC FOR POPS
NORTH MOSTLY THIS AFTERNOON WITH SLGT CHC OR LOW CHC POPS
SOUTH/EAST. THERE WILL BE SOME CAPE VALUES AROUND 750-1250 J/KG
ACROSS THE AREA...BUT THE HIGHEST VALUES WILL OCCUR WITH ANY
BREAKS IN THE CLOUDS TODAY. SPC HAS OUR AREA IN `SEE TEXT` AND
MENTIONS ONLY SMALL POSSIBILITY OF SOME STRONGER WIND GUSTS WITH
ANY CONVECTION THAT DEVELOPS. QPF BASIN AVERAGES...1/2 INCH NORTH
RANGING DOWN TO LIGHT AMTS SOUTH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM FRIDAY/...
WE WILL CONTINUE IN THE WARM SECTOR TONIGHT WITH THE UPPER FLOW
BECOMING A BIT MORE SWRLY ALOFT. A COLD FRONT WILL BE SLOWING ITS
APPROACH INTO WRN NY AND WRN PA. SHOWERS AND SCT THUNDERSTORMS WILL
CONTINUE FROM THE LATE AFTERNOON INTO THE EARLY OVERNIGHT PERIODS.
THE AREAS NORTH/WEST WILL HAVE THE BETTER CHCS FOR THE RAINS. WE
WILL CARRY THE LIKELY POPS INTO THE OVERNIGHT NORTH/WEST AND HOLD
THE HIGHER CHC POPS SOUTH/EAST. QPF...1/2 INCH NORTH 1/10 INCH
SOUTH.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
AN AREA OF LOW PRESSURE IN SERN CANAD WILL WORK ITS WAY EWD. AS IT
DOES A CDFNT WILL CROSS THE AREA FROM W TO E ON FRI INTO FRI
NIGHT. THE LATEST MDL GUID CURRENTLY INDICATES THAT THE FRI
DAYTIME PD COULD BE FAIRLY WET, FOR AT LEAST A PORTION OF THE
AREA, AND THERE COULD BE LOCALIZED CONVECTION WHICH COULD MAKE FOR
PDS OF HEAVY RAIN. IT IS PSBL, IF THE MDLS CONTINUE TO AGREE ON A
LOCATION AS THEY ARE NOW (N AND W) THAT A FFA MAY BE NEEDED AS
RNFL AMTS APPEAR TO BE AOA 1 INCH. THE FRONT SHUD CLEAR THE AREA
DURG THE OVERNIGHT HOURS ON FRI AND CLEARING WILL OCCUR FROM N TO
S. PRECIP MAY LINGER ACRS THE DELMARVA INTO ERLY SAT. THE ECMWF
DOES CLEAR THINGS OUT FASTER THAN THE GFS. BOTH MDLS KEEP THE
FRONT CLOSE BY, SO IT WON`T TAKE MUCH IN THE WAY OF A PERTURBATION
FOR IT TO BRING ANOTHER SHOT OF PRECIP, BUT FOR BOTH MDLS DRY
THINGS OUT BY LATER SAT AT THE LATEST, AS HIGH PRESSURE BUILDS IN.
SUN THEN LOOKS DRY. MUCH LESS CONFIDENCE INTO MON AS THE GFS WANTS
TO BRING A WAVE ACRS THE STALLED FRONT, WHICH WOULD BRING PRECIP,
MAINLY ACRS THE S. THE ECMWF IS DRY DURG THIS TIME. THE CMC ALSO
HAS A WAVE ON MON, BUT ITS OVERALL SYNOPTIC PATN IS A BUT SUSPECT
OVERALL. BY TUE, THE MDLS BRING ANOTHER LOW TO THE N AND ANOTHER
CDFNT ACRS THE REGION, AND ANOTHER CHC OF RAIN.
THIS IS A LOW CONFIDENCE FCST FOR THE EARLY PORTION OF NEXT WEEK
AS IT WILL BE DEPENDENT ON THE POSN OF THE FRONT AND IF ANY WAVES
DEVELOP ALG IT AND WHERE THEY MOVE. BASED ON THE ECMWF`S GENLY
SUPERIOR PERFORMANCE, WANT TO GIVE IT A BIT OF A NOD, BUT CAN`T
RULE OUT A MORE PESSIMIST SOLN EITHER. FOR NOW, WILL BRING IN LOW
POPS MON, LOW CHC POPS ON TUE TO SEE HOW THINGS PLAY OUT AND THEN
A DRY FCST ON WED AS HIGH PRESSURE BUILDS IN.
TEMPS WILL GENLY BE AT OR SLIGHTLY ABV NRML THRU THE PD.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
THE 18Z TAF PACKAGE IS NOT THAT OPTIMISTIC WITH A COUPLE OF ROUNDS
OF SHOWERS AND THUNDERSTORMS EXPECTED WITH CONDITIONS GOING BACK
TO PREDOMINATELY MVFR TONIGHT.
FOR THIS AFTERNOON, CIGS SHOULD BECOME OR BE VFR FROM TAF ONSET
TIME FROM THE KPHL AIRPORTS SOUTH AND EAST. NOT AS CONFIDENT ABOUT
NW TERMINALS. WE ARE EXPECTING AN UPPER AIR DISTURBANCE TO
INITIATE SHOWERS AND THUNDERSTORMS AND MOVE ACROSS (OR HAVE THE
POTENTIAL TO) ALL THE TERMINALS LATER THIS AFTERNOON. MVFR
CONDITIONS ARE LIKELY DURING THE CONVECTION. TIMING IS FROM THE
SOUTHWEST TERMINALS TO THE NORTHEAST TERMINALS. SOUTH TO SOUTHWEST
WINDS WILL AVERAGE AROUND 10 KTS,
FOR TONIGHT AS A WHOLE, IT LOOKS AS THOUGH THERE WILL ONE,
POSSIBLY A SECOND WAVE OF CONVECTION. THE INITIAL WAVE TIMING IS
AN ESTIMATE AT THIS POINT AND THERE MIGHT BE A SECOND WAVE TOWARD
MORNING. REGARDLESS OF THE WAVES, WE ARE EXPECTING CIGS AND VSBYS
TO LOWER TO MVFR AGAIN WITH POSSIBLY SOME IFR CONDITIONS
ESPECIALLY NWRN AIRPORTS AND TERMINALS. LIGHTER SOUTH WINDS
EXPECTED.
ON FRIDAY, EVEN MORE WIDESPREAD SHOWERS AND THUNDERSTORMS ARE
EXPECTED. THERE SHOULD BE A QUICKER STARTING TIME ALSO. WHILE NO
THUNDER HAS BEEN PUT INTO THE TAFS, IT IS LIKELY THEY WILL HAVE AN
IMPACT ON THE TERMINALS WHETHER OR NOT THEY DIRECTLY PASS OVER THEM.
SOUTHWEST WINDS WILL AVERAGE AROUND 10 KNOTS.
OUTLOOK...
FRIDAY NIGHT THROUGH EARLY MORNING SATURDAY...MAINLY MVFR OR IFR
CONDITIONS EXPECTED IN SHOWERS AND PSBL TSTMS. SOME HVY RAIN PSBL.
MDT CONFIDENCE.
REMAINDER OF SATURDAY THROUGH MONDAY...MOSTLY VFR CONDITIONS.
ISOLATED SHWRS/TSTMS REMAIN POSSIBLE, ESPECIALLY MON. SUN SHOULD
BE DRY. MDT TO HIGH CONFIDENCE.
&&
.MARINE...
A MODERATE SOUTH WIND CONTINUES ACROSS THE OCEAN WATERS AND MORE OF
A SWLY WIND ACROSS DEL BAY. OVERALL...THE WIND SPEEDS AND SEAS WILL
REMAIN BELOW SCA CRITERIA TODAY AND TONIGHT. A FEW WIND GUSTS TO 25
KTS MAY OCCUR EARLY THIS MORNING AND LATER TONIGHT...BUT THEY WILL
NOT PERSIST. THE MAIN MARINE HAZARD TODAY AND TONIGHT WOULD BE ANY
GUSTY WINDS ASSD WITH TSTMS WHICH WILL BE AROUND EARLY THIS
MORNING...THIS AFTERNOON AND TONIGHT. SEAS...ON THE OCEAN 3-4 FT AND
DEL BAY 1-2 FT (NORTH) AND 2-3FT (SOUTH).
OUTLOOK...
OVERALL, SUB-SCA CONDITIONS ARE EXPECTED FOR OUR AREA WATERS THROUGH
THE BULK OF THE OUTLOOK PERIOD. GUIDANCE IS SHOWING AN INCREASE IN
THE SOUTHERLY TO SOUTHWESTERLY FLOW DURING FRIDAY AHEAD OF AN
APPROACHING CDFNT. THE WIND CUD GUST TO AROUND 20 KTS OR SO AS
WELL DURG THIS TIME. IN ADDITION, WAVEWATCH GUIDANCE ALSO INDICATES
SEAS RISING TO AROUND 5 OR PSBLY 6 FEET FOR OUR COASTAL WATERS
DURING THIS TIMEFRAME. HOWEVER, THIS GUIDANCE TENDS TO RUN A
LITTLE HIGH IN SOUTHERLY FLOW, AND CONFIDENCE IS BELOW AVERAGE. SO
WILL CONTINUE TO MONITOR FOR ANY PSBL FLAGS. SEAS SHOULD THEN
LOWER BEHIND THE CFP INTO THE WEEKEND, AS WINDS SHIFT TO THE NW.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...NIERENBERG
NEAR TERM...GIGI/O`HARA
SHORT TERM...O`HARA
LONG TERM...NIERENBERG
AVIATION...GIGI/NIERENBERG
MARINE...NIERENBERG/O`HARA
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1133 AM EDT THU AUG 8 2013
.SYNOPSIS...
LOW PRESSURE MOVING ACROSS SOUTHEASTERN CANADA WILL ALLOW A COLD
FRONT TO APPROACH THE REGION ON FRIDAY AND CROSS THE AREA BY LATE
FRIDAY OR EARLY SATURDAY. THIS FRONT WILL EVENTUALLY STALL TO OUR
SOUTH FOR SUNDAY. EARLY NEXT WEEK, A FEW WAVES OF LOW PRESSURE ARE
FORECAST TO MOVE ALONG THE STALLED BOUNDARY. HIGH PRESSURE WILL
THEN BUILD IN TOWARD MIDWEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NOT A CONFIDENT ESTF UPDATE. WE HAVE DECIDED TO COMPROMISE BETWEEN
PREVIOUS FCST AND CURRENT SUGGESTIONS BY THE HRRR AND COSPA. WE
ARE SEEING A SHORT WAVE EMERGE FROM WV AND COUPLED WITH CONVECTIVE
TEMPERATURES BEING REACHED BELIEVE THIS SHOULD START TRIGGERING
AND ENHANCING CONVECTION AS WE MOVE FORWARD. THE PREVIOUS MCS HAS
LEFT A RELATIVELY STABLE POOL NW OF OUR CWA FOR NOW. SO THE
ADJUSTMENTS GOING FORWARD WERE TO LOWER POPS INITIALLY NORTHWEST
AND GIVE THAT SHORT WAVE A BIT MORE CREDIT AND INCREASE POPS IN
THE CENTRAL THIRD OF OUR CWA FOR THIS AFTERNOON. WE DID SEE A
NOTICEABLE DROP OFF IN 925MB OR 850MB MOISTURE OFF THE WALLOPS
SOUNDING THIS MORNING, SO CHANCES WERE KEPT IN THE SERN PART OF
OUR CWA. WE ARE WARMING AT 700MB AND 500MB, SO WITH BULK SHEAR
VALUES BEST NORTH AS WELL AS FORECAST TT(S), WE KEPT THE SOMEWHAT
ENHANCED WORDING TIED TO LIKELY POPS. THE FCST DCAPES ARE NOT
IMPRESSIVE AND NEITHER ARE THETA E DROP WITH HEIGHT, SO ANY STRONG
TO SEVERE ARE GOING TO HAVE TO BE TIED TO SOME RELATIVELY STRONGER
UPDRAFTS OR IF AN EFFECTIVE COOL POOL CAN FORM. THE LATTER DOES
NOT LOOK PROMISING. WE HAVE NOT HAD MANY DRY STRETCHES THIS
SUMMER, BUT THE RELATIVE LACK OF FLOODING RAINS LAST SEVERAL DAYS
HAS PERMITTED FFG AND FFH GUIDANCE TO GET CLOSER TO NORMAL SUMMER
VALUES. SO WHILE A FFW MIGHT STILL OCCUR, THIS WOULD SEEM TO BE
MORE OF AN ISOLATED OCCURRENCE.
12Z SOUNDINGS GIVE 90F AS A POSSIBLE HIGH SOUTHERN PART OF OUR
CWA (CONVECTIVE TEMP LOW 80S), SO BUMPED MAX TEMPS UPWARD IN
DELMARVA, KEPT THE REST RELATIVELY THE SAME.
UPPER HEIGHTS WILL BE RISING THRU THE DAY AND THERE ARE ONLY WEAK
S/W MOVING THRU THE FLOW. BREAKS WILL OCCUR TODAY ALLOWING FOR
POCKETS OF HEATING/INSTABILITY TO DEVELOP. WE WILL GO ALONG WITH THE
DETERMINISTIC MODELS AND MOS AND MOSTLY KEEP THE HIGHER CHC FOR POPS
NORTH MOSTLY THIS AFTERNOON WITH SLGT CHC OR LOW CHC POPS
SOUTH/EAST. THERE WILL BE SOME CAPE VALUES AROUND 750-1250 J/KG
ACROSS THE AREA...BUT THE HIGHEST VALUES WILL OCCUR WITH ANY
BREAKS IN THE CLOUDS TODAY. SPC HAS OUR AREA IN `SEE TEXT` AND
MENTIONS ONLY SMALL POSSIBILITY OF SOME STRONGER WIND GUSTS WITH
ANY CONVECTION THAT DEVELOPS. QPF BASIN AVERAGES...1/2 INCH NORTH
RANGING DOWN TO LIGHT AMTS SOUTH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM FRIDAY/...
WE WILL CONTINUE IN THE WARM SECTOR TONIGHT WITH THE UPPER FLOW
BECOMING A BIT MORE SWRLY ALOFT. A COLD FRONT WILL BE SLOWING ITS
APPROACH INTO WRN NY AND WRN PA. SHOWERS AND SCT THUNDERSTORMS WILL
CONTINUE FROM THE LATE AFTERNOON INTO THE EARLY OVERNIGHT PERIODS.
THE AREAS NORTH/WEST WILL HAVE THE BETTER CHCS FOR THE RAINS. WE
WILL CARRY THE LIKELY POPS INTO THE OVERNIGHT NORTH/WEST AND HOLD
THE HIGHER CHC POPS SOUTH/EAST. QPF...1/2 INCH NORTH 1/10 INCH
SOUTH.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
AN AREA OF LOW PRESSURE IN SERN CANAD WILL WORK ITS WAY EWD. AS IT
DOES A CDFNT WILL CROSS THE AREA FROM W TO E ON FRI INTO FRI
NIGHT. THE LATEST MDL GUID CURRENTLY INDICATES THAT THE FRI
DAYTIME PD COULD BE FAIRLY WET, FOR AT LEAST A PORTION OF THE
AREA, AND THERE COULD BE LOCALIZED CONVECTION WHICH COULD MAKE FOR
PDS OF HEAVY RAIN. IT IS PSBL, IF THE MDLS CONTINUE TO AGREE ON A
LOCATION AS THEY ARE NOW (N AND W) THAT A FFA MAY BE NEEDED AS
RNFL AMTS APPEAR TO BE AOA 1 INCH. THE FRONT SHUD CLEAR THE AREA
DURG THE OVERNIGHT HOURS ON FRI AND CLEARING WILL OCCUR FROM N TO
S. PRECIP MAY LINGER ACRS THE DELMARVA INTO ERLY SAT. THE ECMWF
DOES CLEAR THINGS OUT FASTER THAN THE GFS. BOTH MDLS KEEP THE
FRONT CLOSE BY, SO IT WON`T TAKE MUCH IN THE WAY OF A PERTURBATION
FOR IT TO BRING ANOTHER SHOT OF PRECIP, BUT FOR BOTH MDLS DRY
THINGS OUT BY LATER SAT AT THE LATEST, AS HIGH PRESSURE BUILDS IN.
SUN THEN LOOKS DRY. MUCH LESS CONFIDENCE INTO MON AS THE GFS WANTS
TO BRING A WAVE ACRS THE STALLED FRONT, WHICH WOULD BRING PRECIP,
MAINLY ACRS THE S. THE ECMWF IS DRY DURG THIS TIME. THE CMC ALSO
HAS A WAVE ON MON, BUT ITS OVERALL SYNOPTIC PATN IS A BUT SUSPECT
OVERALL. BY TUE, THE MDLS BRING ANOTHER LOW TO THE N AND ANOTHER
CDFNT ACRS THE REGION, AND ANOTHER CHC OF RAIN.
THIS IS A LOW CONFIDENCE FCST FOR THE EARLY PORTION OF NEXT WEEK
AS IT WILL BE DEPENDENT ON THE POSN OF THE FRONT AND IF ANY WAVES
DEVELOP ALG IT AND WHERE THEY MOVE. BASED ON THE ECMWF`S GENLY
SUPERIOR PERFORMANCE, WANT TO GIVE IT A BIT OF A NOD, BUT CAN`T
RULE OUT A MORE PESSIMIST SOLN EITHER. FOR NOW, WILL BRING IN LOW
POPS MON, LOW CHC POPS ON TUE TO SEE HOW THINGS PLAY OUT AND THEN
A DRY FCST ON WED AS HIGH PRESSURE BUILDS IN.
TEMPS WILL GENLY BE AT OR SLIGHTLY ABV NRML THRU THE PD.
&&
.AVIATION /16Z THURSDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
TODAY...IMPROVING CIGS WITH BREAKS IN THE CLOUDS AND SLOW MIXING
OUT OF ANY LIGHT FOG THIS MORNING...THEN SCT SHOWERS/TSTMS OCCUR
LATER TODAY. LOWER CONDITIONS WITH THE CONVECTION.
TONIGHT...SHOWERS/TSTMS GRADUALLY ENDING. LOWER CIGS/VSBYS AGAIN
INDICTED IN THE GUIDANCE MVFR?...IFR? LOW CONFID OVERALL.
OUTLOOK...
FRIDAY THROUGH EARLY MORNING SATURDAY...MAINLY MVFR OR IFR
CONDITIONS EXPECTED IN SHOWERS AND PSBL TSTMS. SOME HVY RAIN PSBL.
MDT CONFIDENCE.
REMAINDER OF SATURDAY THROUGH MONDAY...MOSTLY VFR CONDITIONS.
ISOLATED SHWRS/TSTMS REMAIN POSSIBLE, ESPECIALLY MON. SUN SHOULD
BE DRY. MDT TO HIGH CONFIDENCE.
&&
.MARINE...
A MODERATE SOUTH WIND CONTINUES ACROSS THE OCEAN WATERS AND MORE OF
A SWLY WIND ACROSS DEL BAY. OVERALL...THE WIND SPEEDS AND SEAS WILL
REMAIN BELOW SCA CRITERIA TODAY AND TONIGHT. A FEW WIND GUSTS TO 25
KTS MAY OCCUR EARLY THIS MORNING AND LATER TONIGHT...BUT THEY WILL
NOT PERSIST. THE MAIN MARINE HAZARD TODAY AND TONIGHT WOULD BE ANY
GUSTY WINDS ASSD WITH TSTMS WHICH WILL BE AROUND EARLY THIS
MORNING...THIS AFTERNOON AND TONIGHT. SEAS...ON THE OCEAN 3-4 FT AND
DEL BAY 1-2 FT (NORTH) AND 2-3FT (SOUTH).
OUTLOOK...
OVERALL, SUB-SCA CONDITIONS ARE EXPECTED FOR OUR AREA WATERS THROUGH
THE BULK OF THE OUTLOOK PERIOD. GUIDANCE IS SHOWING AN INCREASE IN
THE SOUTHERLY TO SOUTHWESTERLY FLOW DURING FRIDAY AHEAD OF AN
APPROACHING CDFNT. THE WIND CUD GUST TO AROUND 20 KTS OR SO AS
WELL DURG THIS TIME. IN ADDITION, WAVEWATCH GUIDANCE ALSO INDICATES
SEAS RISING TO AROUND 5 OR PSBLY 6 FEET FOR OUR COASTAL WATERS
DURING THIS TIMEFRAME. HOWEVER, THIS GUIDANCE TENDS TO RUN A
LITTLE HIGH IN SOUTHERLY FLOW, AND CONFIDENCE IS BELOW AVERAGE. SO
WILL CONTINUE TO MONITOR FOR ANY PSBL FLAGS. SEAS SHOULD THEN
LOWER BEHIND THE CFP INTO THE WEEKEND, AS WINDS SHIFT TO THE NW.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...NIERENBERG
NEAR TERM...GIGI/O`HARA
SHORT TERM...O`HARA
LONG TERM...NIERENBERG
AVIATION...NIERENBERG/O`HARA
MARINE...NIERENBERG/O`HARA
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
908 AM EDT THU AUG 8 2013
.SYNOPSIS...
LOW PRESSURE MOVING ACROSS SOUTHEASTERN CANADA WILL ALLOW A COLD
FRONT TO APPROACH THE REGION ON FRIDAY AND CROSS THE AREA BY LATE
FRIDAY OR EARLY SATURDAY. THIS FRONT WILL EVENTUALLY STALL TO OUR
SOUTH FOR SUNDAY. EARLY NEXT WEEK, A FEW WAVES OF LOW PRESSURE ARE
FORECAST TO MOVE ALONG THE STALLED BOUNDARY. HIGH PRESSURE WILL
THEN BUILD IN TOWARD MIDWEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
QUITE THE FORECASTING CONUNDRUM FOR TODAY ACROSS OUR CWA. AS BEST
KINEMATIC AND THERMODYNAMIC SUPPORT FOR CONVECTION IS AT ODDS WITH
ONGOING CLOUD COVER AND LOWER EXPECTED TEMPERATURES. LIKE
YESTERDAY MOST OF THE MESOSCALE MODELS ARE NOT VERIFYING WELL AT
ALL IN OUR CWA THIS MORNING AND THIS INCLUDES THE RAP. CLOSEST TO
REALITY IN OUR CWA HAS BEEN THE NSSL WRF. BECAUSE OF THEIR HOURLY
INITIALIZATION THE HRRR AND COSPA HAVE BEEN DOING OK 1-3HRS DOWN
THE ROAD; THE SAME CAN NOT BE SAID FOR THE RAP. THE LATTER PAIR
ARE DISSIPATING THE MCS BEFORE MUCH OF IT CAN GET INTO OUR NRN CWA
THIS MORNING AND THEN ARE ESTABLISHING A DIFFERENTIAL HEATING
BOUNDARY INDUCED CONVECTION CLOSE TO THE PHL METRO AREA LATER THIS
MORNING. GOING AGAINST THIS IS RELATIVELY DRIER AIR COMING IN
FROM THE ATLANTIC ACROSS THE SERN PART OF OUR CWA. WANT TO SEE HOW
CLEARING EVOLVES BEFORE MAKING ANY BIG CHANGES AS THIS ESTF UPDATE
WILL KEEP THE HIGHEST POPS NW. THERE IS CLEARING BEHIND THE
DEPARTING MCS WESTERN NY AND FORECAST CONVECTIVE TEMPS ARE LOWER
NORTH THAN SOUTH. 12Z SOUNDINGS GIVE 90F AS A POSSIBLE HIGH
SOUTHERN PART OF OUR CWA (CONVECTIVE TEMP LOW 80S), SO BUMPED MAX
TEMPS UPWARD IN DELMARVA, KEPT THE REST RELATIVELY THE SAME.
AN ILL DEFINED WARM FRONT ACROSS THE AREA EARLY THIS MORNING WILL
MOVE OFF TO THE NORTH/EAST LATER TODAY. WE WILL SPEND THE REST OF
TODAY (AND TONIGHT) IN THE WARM SECTOR. ABUNDANT MOISTURE WILL
REMAIN IN PLACE ACROSS THE REGION.
ANOTHER BATCH OF SHOWERS/TSTMS ACROSS WRN NY APPEARS TO BE
WEAKENING SLOW ALSO. IT MAY BRING EXTRA CLOUDINESS LATER THIS
MORNING ACROSS THE NORTH.
UPPER HEIGHTS WILL BE RISING THRU THE DAY AND THERE ARE ONLY WEAK
S/W MOVING THRU THE FLOW. BREAKS WILL OCCUR TODAY ALLOWING FOR
POCKETS OF HEATING/INSTABILITY TO DEVELOP. WE WILL GO ALONG WITH THE
DETERMINISTIC MODELS AND MOS AND MOSTLY KEEP THE HIGHER CHC FOR POPS
NORTH/WEST MOSTLY THIS AFTERNOON WITH SLGT CHC OR LOW CHC POPS
SOUTH/EAST. THERE WILL BE SOME CAPE VALUES AROUND 750-1250 J/KG
ACROSS THE AREA...BUT THE HIGHEST VALUES WILL OCCUR WITH ANY BREAKS
IN THE CLOUDS TODAY. SPC HAS OUR AREA IN `SEE TEXT` AND MENTIONS
ONLY SMALL POSSIBILITY OF SOME STRONGER WIND GUSTS WITH ANY
CONVECTION THAT DEVELOPS. QPF...1/2 INCH NORTH RANGING DOWN TO
LIGHT AMTS SOUTH.
TEMPERATURES WILL BE HELD IN CHECK EARLY TODAY WITH ABUNDANT AMOUNTS
OF CLOUDS EARLY. WE WENT WITH MOSTLY MAV MOS AND OFFERED LOW 80S
OVER MOST AREAS TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM FRIDAY/...
WE WILL CONTINUE IN THE WARM SECTOR TONIGHT WITH THE UPPER FLOW
BECOMING A BIT MORE SWRLY ALOFT. A COLD FRONT WILL BE SLOWING ITS
APPROACH INTO WRN NY AND WRN PA. SHOWERS AND SCT THUNDERSTORMS WILL
CONTINUE FROM THE LATE AFTERNOON INTO THE EARLY OVERNIGHT PERIODS.
THE AREAS NORTH/WEST WILL HAVE THE BETTER CHCS FOR THE RAINS. WE
WILL CARRY THE LIKELY POPS INTO THE OVERNIGHT NORTH/WEST AND HOLD
THE HIGHER CHC POPS SOUTH/EAST. QPF...1/2 INCH NORTH 1/10 INCH
SOUTH.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
AN AREA OF LOW PRESSURE IN SERN CANAD WILL WORK ITS WAY EWD. AS IT
DOES A CDFNT WILL CROSS THE AREA FROM W TO E ON FRI INTO FRI
NIGHT. THE LATEST MDL GUID CURRENTLY INDICATES THAT THE FRI
DAYTIME PD COULD BE FAIRLY WET, FOR AT LEAST A PORTION OF THE
AREA, AND THERE COULD BE LOCALIZED CONVECTION WHICH COULD MAKE FOR
PDS OF HEAVY RAIN. IT IS PSBL, IF THE MDLS CONTINUE TO AGREE ON A
LOCATION AS THEY ARE NOW (N AND W) THAT A FFA MAY BE NEEDED AS
RNFL AMTS APPEAR TO BE AOA 1 INCH. THE FRONT SHUD CLEAR THE AREA
DURG THE OVERNIGHT HOURS ON FRI AND CLEARING WILL OCCUR FROM N TO
S. PRECIP MAY LINGER ACRS THE DELMARVA INTO ERLY SAT. THE ECMWF
DOES CLEAR THINGS OUT FASTER THAN THE GFS. BOTH MDLS KEEP THE
FRONT CLOSE BY, SO IT WON`T TAKE MUCH IN THE WAY OF A PERTURBATION
FOR IT TO BRING ANOTHER SHOT OF PRECIP, BUT FOR BOTH MDLS DRY
THINGS OUT BY LATER SAT AT THE LATEST, AS HIGH PRESSURE BUILDS IN.
SUN THEN LOOKS DRY. MUCH LESS CONFIDENCE INTO MON AS THE GFS WANTS
TO BRING A WAVE ACRS THE STALLED FRONT, WHICH WOULD BRING PRECIP,
MAINLY ACRS THE S. THE ECMWF IS DRY DURG THIS TIME. THE CMC ALSO
HAS A WAVE ON MON, BUT ITS OVERALL SYNOPTIC PATN IS A BUT SUSPECT
OVERALL. BY TUE, THE MDLS BRING ANOTHER LOW TO THE N AND ANOTHER
CDFNT ACRS THE REGION, AND ANOTHER CHC OF RAIN.
THIS IS A LOW CONFIDENCE FCST FOR THE EARLY PORTION OF NEXT WEEK
AS IT WILL BE DEPENDENT ON THE POSN OF THE FRONT AND IF ANY WAVES
DEVELOP ALG IT AND WHERE THEY MOVE. BASED ON THE ECMWF`S GENLY
SUPERIOR PERFORMANCE, WANT TO GIVE IT A BIT OF A NOD, BUT CAN`T
RULE OUT A MORE PESSIMIST SOLN EITHER. FOR NOW, WILL BRING IN LOW
POPS MON, LOW CHC POPS ON TUE TO SEE HOW THINGS PLAY OUT AND THEN
A DRY FCST ON WED AS HIGH PRESSURE BUILDS IN.
TEMPS WILL GENLY BE AT OR SLIGHTLY ABV NRML THRU THE PD.
&&
.AVIATION /13Z THURSDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
TODAY...IMPROVING CIGS WITH BREAKS IN THE CLOUDS AND SLOW MIXING
OUT OF ANY LIGHT FOG THIS MORNING...THEN SCT SHOWERS/TSTMS OCCUR
LATER TODAY. LOWER CONDITIONS WITH THE CONVECTION. THE PROB30 FROM
EARLIER WAS RETAINED IN THE 06Z TAFS...WE`LL DECIDE LATER WHAT TO
DO FOR THE 12Z TAFS...SINCE THE 9 HOUR WINDOW OF `NO PROB30S` WILL
BE OPEN AT THAT POINT.
TONIGHT...SHOWERS/TSTMS GRADUALLY ENDING. LOWER CIGS/VSBYS AGAIN
INDICTED IN THE GUIDANCE MVFR?...IFR? LOW CONFID OVERALL.
OUTLOOK...
FRIDAY THROUGH EARLY MORNING SATURDAY...MAINLY MVFR OR IFR
CONDITIONS EXPECTED IN SHOWERS AND PSBL TSTMS. SOME HVY RAIN PSBL.
MDT CONFIDENCE.
REMAINDER OF SATURDAY THROUGH MONDAY...MOSTLY VFR CONDITIONS.
ISOLATED SHWRS/TSTMS REMAIN POSSIBLE, ESPECIALLY MON. SUN SHOULD
BE DRY. MDT TO HIGH CONFIDENCE.
&&
.MARINE...
A MODERATE SOUTH WIND CONTINUES ACROSS THE OCEAN WATERS AND MORE OF
A SWLY WIND ACROSS DEL BAY. OVERALL...THE WIND SPEEDS AND SEAS WILL
REMAIN BELOW SCA CRITERIA TODAY AND TONIGHT. A FEW WIND GUSTS TO 25
KTS MAY OCCUR EARLY THIS MORNING AND LATER TONIGHT...BUT THEY WILL
NOT PERSIST. THE MAIN MARINE HAZARD TODAY AND TONIGHT WOULD BE ANY
GUSTY WINDS ASSD WITH TSTMS WHICH WILL BE AROUND EARLY THIS
MORNING...THIS AFTERNOON AND TONIGHT. SEAS...ON THE OCEAN 3-4 FT AND
DEL BAY 1-2 FT (NORTH) AND 2-3FT (SOUTH).
OUTLOOK...
OVERALL, SUB-SCA CONDITIONS ARE EXPECTED FOR OUR AREA WATERS THROUGH
THE BULK OF THE OUTLOOK PERIOD. GUIDANCE IS SHOWING AN INCREASE IN
THE SOUTHERLY TO SOUTHWESTERLY FLOW DURING FRIDAY AHEAD OF AN
APPROACHING CDFNT. THE WIND CUD GUST TO AROUND 20 KTS OR SO AS
WELL DURG THIS TIME. IN ADDITION, WAVEWATCH GUIDANCE ALSO INDICATES
SEAS RISING TO AROUND 5 OR PSBLY 6 FEET FOR OUR COASTAL WATERS
DURING THIS TIMEFRAME. HOWEVER, THIS GUIDANCE TENDS TO RUN A
LITTLE HIGH IN SOUTHERLY FLOW, AND CONFIDENCE IS BELOW AVERAGE. SO
WILL CONTINUE TO MONITOR FOR ANY PSBL FLAGS. SEAS SHOULD THEN
LOWER BEHIND THE CFP INTO THE WEEKEND, AS WINDS SHIFT TO THE NW.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...NIERENBERG
NEAR TERM...GIGI/O`HARA
SHORT TERM...O`HARA
LONG TERM...NIERENBERG
AVIATION...NIERENBERG/O`HARA
MARINE...NIERENBERG/O`HARA
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
1015 PM EDT FRI AUG 9 2013
.DISCUSSION...
ATLC RIDGE AXIS OVER THE DEEP SOUTH WILL MAINTAIN A DEEP SERLY FLOW
ACRS THE REGION OVERNIGHT. DIURNAL CONVECTION ONCE AGAIN
CONCENTRATED OVER THE W PENINSULA WITH LITTLE SIG ACTIVITY PAST
SUNSET. PERSISTENT CELLS OVER N LAKE COUNTY GENERATED LCL HEAVY RAIN
IN THE LEESBURG AREA...KLEE REPORTED 1.55" OF PRECIP AS OF 02Z.
OTHER THAN THAT...ONLY KFPR REPORTED MEASURABLE PRECIP...AND ONLY
0.03" AT THAT.
NO SIGN OF REDEVELOPMENT DESPITE THE FACT THE FL PENINSULA HAS
GAINED THE BACK SIDE OF THE TUTT. SAT PICS/SFC OBS INDICATE SKIES
SLOWLY CLEARING SINCE SUNSET...WHILE WIND PROFILERS INDICATE DEEP
S/SE FLOW THRU 10KFT. RUC ANALYSIS INDICATES H100-H70 MEAN RH VALUES
AOB 70PCT BTWN THE BAHAMAS AND THE FL PENINSULA. ISOLD SHRAS DVLPG
DOWNWIND OF GRAND BAHAMA ISLAND...SERLY FLOW WILL MAKE IT DIFFICULT
TO PUSH THESE ONSHORE. WILL KEEP SLGT CHANCE IN THE FOR THE COAST S
OF THE CAPE...BUT ANY PRECIP WILL HAVE NEGLIGIBLE IMPACT.
&&
.AVIATION...
VFR ALL SITES UNLESS OTHERWISE STATED. THRU 10/06Z...E/SE SFC WNDS
DECREASING TO 3-6KTS. BTWN 10/14Z-10/17Z...E/SE SFC WNDS INCREASING
TO 12-15KTS WITH OCNL SFC G20-22KTS S OF KTIX. BTWN 10/17Z-10/23Z...
ISOLD MVFR SHRAS/IFR TSRAS ALL SITES MVG NW ARND 15KTS.
&&
.MARINE...
HI PRES RIDGE OVER THE DEEP SOUTH WILL MAINTAIN A LIGHT TO GENTLE
E/SE BREEZE OVERNIGHT...SEAS 2-3FT WITH DOMINANT PDS 4-5SECS. BRIEF
ISOLD SHRAS OVER THE GULF STREAM AND DOWNWIND OF THE NRN BAHAMAS.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
FORECAST....BRAGAW
IMPACT WX...ULRICH
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
900 PM EDT FRI AUG 9 2013
.UPDATE (REST OF TONIGHT THROUGH SUNDAY)...
00Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS THE REGION ON THE EASTERN
SIDE OF A RETROGRADING TUTT CELL OVER THE SE GULF OF MEXICO. STILL
AMPLE COLUMN MOISTURE IN PLACE TODAY. THIS MOISTURE COMBINED WITH A
FAVORABLE EASTERLY FLOW FOR WEST COAST SEA-BREEZE INTERACTIONS...AND
RESULTED IN ANOTHER ACTIVE AFTERNOON/EARLY EVENING OF CONVECTION
ACROSS MUCH OF WEST-CENTRAL AND SOUTHWEST FLORIDA. MUCH OF THE
INSTABILITY WITHIN THE COLUMN HAS NOW BEEN "WORKED OVER" BY THE
EARLIER STORMS...AND THIS COMBINED WITH THE LOSS OF DIURNAL HEATING
HAS RESULTED IN A STEADY REDUCTION IN STORM COVERAGE AND INTENSITY
OVER THE PAST 90 MINUTES. STILL A FEW SHOWER OUT THERE AND WILL KEEP
A 30% POP IN THE GRIDS...ALMOST REGION-WIDE UNTIL 03Z...AND THEN
REMOVE RAIN CHANCES FROM THE LAND ZONES. THE REMAINDER OF THE
OVERNIGHT AFTER LATE EVENING SHOULD FEATURE A DECAYING CIRRUS SHIELD
AND MAINLY DRY CONDITIONS.
FOR SATURDAY...MODEL ENSEMBLES ARE IN GOOD AGREEMENT SHOWING A
TONGUE OF DRIER MID/UPPER LEVEL AIR ARRIVING ACROSS SOUTHEAST
FLORIDA BEHIND THE DEPARTING TUTT BY THE MORNING HOURS AND THEN
EXPANDING NORTH AND EAST THROUGH THE DAY. LOOKING AT THE LATEST
GUIDANCE...IT IS UNLIKELY THAT ENOUGH DRY AIR WILL ARRIVE OVER MOST
OF OUR FORECAST AREA TO SIGNIFICANTLY SLOW THE CONVECTIVE POTENTIAL.
PERHAPS DOWN TOWARD FORT MYERS LATE IN THE DAY A DECENT REDUCTION IN
PW WILL BE POSSIBLE...HOWEVER WITH EASTERLY FLOW...THIS REGION TENDS
TO CONVECT BY EARLY AFTERNOON ANYWAY. THE ATMOSPHERE WILL CERTAINLY
NOT BE QUITE AS CONDUCIVE AND FRIENDLY TO CONVECTION ON SATURDAY AS
IT HAS BEEN THE PAST FEW DAYS...HOWEVER WILL SEE SHOW A 40%
AFTERNOON/EARLY EVENING RAIN PERCENTAGE ALONG AND WEST OF THE I-75
CORRIDOR IN CLOSEST PROXIMITY TO THE SEA-BREEZE. COVERAGE SHOULD NOT
BE SIGNIFICANT ENOUGH TO REALLY IMPACT OUTDOOR ACTIVITIES FOR AN
EXTENDED DURATION...BUT THE STORMS WILL BE SCATTERED AROUND AFTER
1-2 PM.
NOW...BY SUNDAY...THE DRY AIR ALOFT WILL HAVE EXPANDED OVER THE
ENTIRE AREA. THIS COMBINED WITH BETTER SYNOPTIC SUPPRESSION UNDER A
BUILDING UPPER RIDGE SHOULD KEEP OUR CONVECTIVE COVERAGE FAR BELOW
SEASONAL NORMALS FOR MID-AUGUST. THERE WILL HOWEVER BE A TRADE OFF.
LESS CONVECTION AND LARGE SCALE SUBSIDENCE WILL ALLOW TEMPERATURES
TO GET QUITE HOT. LIKELY LOOKING AT WIDESPREAD MIDDLE 90S AWAY FROM
THE IMMEDIATE COAST WITH A FEW SPOTS POSSIBLY MAKING A RUN AT THE
UPPER 90S.
&&
.AVIATION...
AREAS OF SHOWERS AND THUNDERSTORMS HAVE MOVED OFFSHORE OVER THE GULF
BUT ANOTHER SMALL CLUSTER IS MOVING NORTHWESTWARD THROUGH THE
CENTRAL PENINSULA. THOSE CONVECTIVE ELEMENTS MAY IMPACT LAL WITH A
REMOTE CHANCE OF GLAZING TPA AND PIE. AFTER THOSE FEW CELLS ARE OUT
OF THE PICTURE... THE NIGHT SHOULD BE QUIET UNTIL STORMS BEGIN
TOMORROW DEVELOPING NEAR THE SOUTHERN AIRPORTS AND PROPAGATING NORTH
UNDER SOUTHEASTERLY FLOW.
&&
.MARINE...
THE MAIN CONCERN THROUGH THE REST OF FRIDAY AFTERNOON AND EVENING
WILL BE STRONG THUNDERSTORMS OVER THE WATERS...ESPECIALLY OVER
TAMPA BAY AND THE NEAR SHORE WATERS...WITH THE MOST FAVORABLE
TIME FRAME FOR STRONG THUNDERSTORMS BETWEEN 4 PM AND 7 PM.
ACTIVITY SHOULD WIND DOWN A FEW HOURS AFTER SUNSET.
OUTSIDE OF CONVECTION...WIND SPEEDS WILL GENERALLY REMAIN 15
KNOTS OR LESS THROUGH THE NEXT SEVERAL DAYS WITH SEAS AROUND 3
FEET OR LESS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 74 92 77 93 / 30 40 20 20
FMY 73 93 76 93 / 30 30 20 20
GIF 74 94 75 96 / 30 30 10 20
SRQ 75 92 77 92 / 30 40 20 20
BKV 72 93 73 95 / 30 40 20 20
SPG 77 92 79 92 / 30 40 20 20
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE...MROCZKA
AVIATION...PAXTON
FORECAST DISCUSSION BELOW.
20
PREVIOUS LONG TERM DISCUSSION/FRIDAY NIGHT THROUGH WEDNESDAY/...
/ISSUED 414 AM EDT THU AUG 8 2013/
FLAT UPPER RIDGE CONTINUES OVER THE REGION THROUGH THE WEEKEND WITH
MULTIPLE IMPULSES IN THE UPPER FLOW AFFECTING THE CWA. PLENTY OF
AVAILABLE MOISTURE COMBINED WITH THE DYNAMICS SHOULD SUPPORT AT LEAST
CHANCE OR SLIGHT CHANCE POPS WITH A TREND TOWARD THE DIURNAL PATTERN.
BY THE BEGINNING OF NEXT WEEK AN UPPER TROUGH DEEPENING OVER THE
NORTHEAST SHOULD HELP PUSH A FRONT SOUTHWARD INTO GA. NOT SURE AT
THIS TIME HOW FAR INTO THE CWA THE FRONT WILL ACTUALLY GET...BUT
THERE IS SOME INDICATION THAT THERE MAY BE SOME DRYING ACROSS THE
NORTH BY THE END OF THE PERIOD. NOT CONFIDENT IT WILL BE DRY ENOUGH
TO REMOVE ANY POPS HOWEVER.
41
HYDROLOGY...
AN AREA OF SHOWERS AND THUNDERSTORMS CONTINUES TO PUSH INTO NORTH
GEORGIA...THOUGH INTENSITY HAS BEEN DECREASING THIS EVENING. THE
STRONGEST DEVELOPMENT OCCURRED OVER DADE AND WALKER
COUNTIES...PROMPTING A FLASH FLOOD WARNING THROUGH 1130 PM THIS
EVENING. FLOOD WATCH CONTINUES TO BE IN EFFECT UNTIL FRIDAY
MORNING. ALTHOUGH ACTIVITY IS FORECAST TO DECREASE TONIGHT...WITH
PW/S AROUND 2 INCHES AGAIN ON FRIDAY...IT IS POSSIBLE THAT THE
FLOOD WATCH WILL NEED TO BE EXTENDED FURTHER IN TIME. WITH TIME
LEFT TO MAKE THE DECISION THOUGH...WILL LET THE MIDNIGHT SHIFT
MAKE THIS DECISION BASED ON LATEST TRENDS AND GUIDANCE.
&&
.AVIATION...
06Z UPDATE...
EXPECT DEGRADING CONDITIONS THROUGH THE OVERNIGHT...WITH GENERALLY
VFR ACROSS THE AREA BECOMING IFR LEVELS AFTER 08-09Z...EXCEPT FOR
A FEW OF THE SOUTHERN TAF SITES WHERE MVFR IS EXPECTED.
IMPROVEMENT EXPECTED 15-16Z WITH CONVECTION POTENTIAL AGAIN IN THE
LATE MORNING THROUGH AFTERNOON. SE WINDS OVERNIGHT WILL BECOME SW
AROUND 14-16Z...AND WILL GENERALLY BE 6 KTS OR LESS THROUGH THE PERIOD.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM ON MORNING CIGS.
HIGH CONFIDENCE ON ALL OTHER ELEMENTS.
31
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 88 71 89 72 / 50 30 40 20
ATLANTA 87 73 88 73 / 50 30 40 30
BLAIRSVILLE 82 68 84 67 / 60 40 50 40
CARTERSVILLE 88 70 88 71 / 60 40 50 30
COLUMBUS 91 74 92 74 / 40 20 30 20
GAINESVILLE 85 71 88 72 / 60 40 50 30
MACON 91 71 93 73 / 30 20 20 20
ROME 89 71 88 72 / 60 40 50 40
PEACHTREE CITY 88 71 89 70 / 40 30 40 20
VIDALIA 92 73 93 75 / 20 20 20 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 6 AM EDT EARLY THIS MORNING FOR THE
FOLLOWING ZONES: BANKS...BARROW...BARTOW...BUTTS...CARROLL...
CATOOSA...CHATTOOGA...CHEROKEE...CLARKE...CLAYTON...COBB...
COWETA...DADE...DAWSON...DEKALB...DOUGLAS...FANNIN...FAYETTE...
FLOYD...FORSYTH...GILMER...GORDON...GREENE...GWINNETT...HALL...
HARALSON...HEARD...HENRY...JACKSON...JASPER...LAMAR...LUMPKIN...
MADISON...MERIWETHER...MORGAN...MURRAY...NEWTON...NORTH FULTON...
OCONEE...OGLETHORPE...PAULDING...PICKENS...PIKE...POLK...
PUTNAM...ROCKDALE...SOUTH FULTON...SPALDING...TALIAFERRO...
TOWNS...TROUP...UNION...WALKER...WALTON...WHITE...WHITFIELD...
WILKES.
&&
$$
SHORT TERM...31
LONG TERM....41
AVIATION...31
AREA FORECAST DISCUSSION
NWS BOISE ID
950 AM MDT THU AUG 8 2013
.DISCUSSION...SPEED MAX MOVING NORTH ON THE EAST SIDE OF THE UPPER
LOW IS EVIDENT IN FAR NE CA AS OF 930 AM MDT. THIS IS ALREADY
HELPING TO INITIATE AND STRENGTHEN CONVECTION IN SE OREGON...AND
THE EFFECT IS GOING TO BE FELT EVEN IN OUR SW IDAHO ZONES. AS WE
HEAT UP TODAY...WE EXPECT SCATTERED SHOWERS AND THUNDERSTORMS
OVER A LARGE PORTION OF THE CWA. RED FLAG WARNINGS ARE STILL IN
EFFECT FOR MUCH OF THE AREA. LATEST HRRR OUTPUT HAS BEEN
CONSISTENT IN BRINGING CONVECTION EVEN INTO THE VALLEYS...SO HAVE
SLIGHTLY RAISED POPS IN THE LOWER ELEVATIONS FOR THIS AFTERNOON.
CONCERNING TOMORROW...THE DRY SLOT APPEARS HEADED MAINLY FOR THE
IDAHO SIDE OF OUR CWA. WE HAVE ALREADY UPDATED POP GRIDS TO TAKE
THIS INTO ACCOUNT FOR FRIDAY...AND MAY TWEAK THEM A BIT MORE THIS
AFTERNOON BEFORE THE FINAL PACKAGE COMES OUT. ANOTHER UPDATE WILL
BE DONE SHORTLY.
&&
.AVIATION...VFR. THIS MORNING...SCATTERED TO BROKEN MID LEVEL
CLOUDS AND ISOLATED SHOWERS. THIS AFTERNOON THROUGH TONIGHT...
ISOLATED THUNDERSTORMS OVER THE WEST CENTRAL IDAHO AND BOISE
MOUNTAINS. SCATTERED THUNDERSTORMS ACROSS EASTERN OREGON AND
SOUTHWEST IDAHO SOUTH OF THE SNAKE RIVER VALLEY. SURFACE WINDS...
LIGHT THIS MORNING THEN NORTH TO NORTHWEST 5-15 KTS THIS AFTERNOON
AND TONIGHT. LOCAL GUSTY WINDS NEAR THUNDERSTORMS. WINDS ALOFT...
NORTHEAST TO SOUTHEAST AROUND 10 KTS.
&&
.PREV DISCUSSION...
SHORT TERM...TODAY THROUGH FRIDAY...UPPER LOW OFF THE NORTHERN
CALIFORNIA COAST WILL MOVE LITTLE THROUGH FRIDAY AS IT MEANDERS
OFFSHORE. LATEST SATELLITE IMAGERY REVEALS PARTLY TO MOSTLY CLOUDY
SKIES ACROSS SE OREGON AND SW IDAHO...BUT RADAR RETURNS ONLY SHOWED
ISOLATED SHOWERS ACROSS PORTIONS OF SE OREGON AND IN SW IDAHO SOUTH
OF THE SNAKE RIVER. THERE HAS NOT BEEN LIGHTNING FOR SEVERAL HOURS
AND EXPECT ONLY ISOLATED SHOWERS THIS MORNING. SHORTWAVES ROTATING
THROUGH THE REGION ASSOCIATED WITH UPPER LOW...COMBINED WITH
INSTABILITY FROM DAYTIME HEATING...WILL SUPPORT ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS THIS AFTERNOON. THE COVERAGE WILL BE
GREATER THAN WEDNESDAY IN SW IDAHO...ESPECIALLY IN THE HIGHER
TERRAIN...DUE TO AN INCREASE IN MOISTURE. THERE WILL ALSO BE ANOTHER
ROUND OF SCATTERED THUNDERSTORMS IN SE OREGON THIS AFTERNOON.
CONVECTION WILL REMAIN ACTIVE THIS EVENING THEN GRADUALLY DIMINISH
OVERNIGHT. MODELS SHOW THE MOST ACTIVE AREA WILL BE ACROSS SE OREGON
WITH CONVECTION LINGERING INTO FRIDAY MORNING AS MORE SHORT WAVES
PIVOT AROUND THE UPPER LOW. MEANWHILE...MUCH DRIER AIR OVER SOUTHERN
NEVADA WILL MOVE NORTHWARD AND REACH PORTIONS OF SW IDAHO ON FRIDAY.
POPS MAY NEED TO BE TRIMMED LOWER IF THIS MODEL TREND CONTINUES. IN
THE MEANTIME...WILL KEEP GENERALLY ISOLATED POPS ACROSS THE HIGHER
TERRAIN WITH NO MENTION OF CONVECTION IN THE SW IDAHO VALLEYS.
CHANCE OF SHOWERS/THUNDERSTORMS WILL CONTINUE IN SE OREGON INTO THE
AFTERNOON DUE TO THE CLOSER PROXIMITY TO THE LOW. TEMPERATURES WILL
BE A FEW DEGREES LOWER TODAY AND FRIDAY...ALTHOUGH STILL A LITTLE
ABOVE NORMAL. NO SIGNIFICANT WINDS ARE FORECAST...EXCEPT LOCALLY
STRONG WIND GUSTS WILL ACCOMPANY THE THUNDERSTORMS.
LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...LITTLE CHANGE IN THE
WEATHER PATTERN AS A CLOSED UPPER LEVEL LOW WILL BE OVER NORTHERN
CALIFORNIA FRIDAY NIGHT AND THEN SLOWLY LIFT TO THE NORTH ALONG THE
WEST COAST SATURDAY THROUGH MONDAY NIGHT AND THEN REMAIN NEARLY
STATIONARY JUST OFF THE WEST COAST OF WASHINGTON TUESDAY THROUGH
WEDNESDAY. WITH THE LOW SHIFTING TO THE NORTH PRECIPITATION
ASSOCIATED WITH THIS LOW WILL ALSO SHIFT TO NORTHERN ZONES AND
DECREASE TO A SLIGHT CHANCE. TEMPERATURES THROUGH THE EXTENDED
PERIOD WILL REMAIN A FEW DEGREES ABOVE NORMAL.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...RED FLAG WARNING UNTIL 6 AM MDT FRIDAY IDZ402-403-421-426.
RED FLAG WARNING UNTIL MIDNIGHT MDT FRIDAY NIGHT IDZ423.
OR...RED FLAG WARNING UNTIL MIDNIGHT MDT /11 PM PDT/ FRIDAY NIGHT
ORZ636-637.
&&
$$
WEATHER.GOV/BOISE
DISCUSSION...SP
AVIATION.....JT
PREV SHORT TERM...BW
PREV LONG TERM....JA
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
742 PM EDT FRI AUG 9 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 340 PM EDT FRI AUG 9 2013
SCATTERED SHOWERS WILL LINGER OVER SOUTHERN COUNTIES TONIGHT AS A
REMNANT BOUNDARY DRIFTS SLOWLY SOUTH OF THE OHIO RIVER. A SECONDARY
COLD FRONT WILL MOVE ACROSS THE REGION SATURDAY...WITH HIGH PRESSURE
AND DRIER AIR BUILDING INTO CENTRAL INDIANA FOR SATURDAY NIGHT AND
SUNDAY. A STRONGER COLD FRONT WILL BRING THE NEXT CHANCE FOR SHOWERS
AND THUNDERSTORMS MONDAY AND TUESDAY. COOLER AIR WILL EXPAND INTO
THE OHIO VALLEY IN THE WAKE OF THIS FRONT FOR MUCH OF THE REST OF
NEXT WEEK.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 342 PM EDT FRI AUG 9 2013
MUCH OF THE THICKER CLOUD COVER HAS SCATTERED OUT INTO A CU FIELD
THIS AFTERNOON...AS THE OLD FRONTAL BOUNDARY NOW APPEARS TO HAVE
SHIFTED SOUTH CLOSER TO THE OHIO RIVER. WITH THE INCREASING
SUNSHINE...TEMPS HAD WARMED INTO LOWER 80S OVER MUCH OF THE REGION
AS OF 19Z.
DRIER AIRMASS SLOWLY ADVECTING SOUTH INTO THE FORECAST AREA...WITH
DEWPOINTS NOW INTO THE LOWER AND MIDDLE 60S NORTH OF I-70. WHILE
DEEPER MOISTURE IS STEADILY BEING SHOVED SOUTH...REMNANT DISTURBANCE
ALOFT OVER SOUTHEAST MISSOURI WILL NEED TO BE MONITORED AS IT TRACKS
INTO THE OHIO VALLEY TONIGHT. STEERING FLOW ALOFT GENERALLY
E/NE...WHICH SHOULD BRING CONVECTION ASSOCIATED WITH THE DISTURBANCE
INTO SOUTHWEST INDIANA BY 22Z. UNLIKE THE MCV FROM LAST NIGHT...THIS
FEATURE IS WEAKER AND IS TRACKING FURTHER TO THE SOUTH.
ADDITIONALLY...INSTABILITY GRADIENT JUST GRAZES SOUTHERN FORECAST
AREA WITH ONLY SUBTLE DESTABILIZATION EXPECTED BETWEEN NOW AND
SUNSET. ONCE AGAIN...CURRENT HRRR GUIDANCE SEEMS TO HAVE CAPTURED
CONVECTION WELL AND HAVE UTILIZED IT FOR THE NEXT SEVERAL HOURS.
WILL CARRY LOW CHANCE POPS MAINLY ALONG AND SOUTH OF A SULLIVAN-
BLOOMINGTON-GREENSBURG LINE THIS EVENING...GRADUALLY ENDING FROM
WEST TO EAST OVERNIGHT. COULD SEE A FEW RUMBLES OF THUNDER OVER
EXTREME SOUTHERN COUNTIES INTO THE EVENING AS WELL.
PRESENCE OF THE DRIER AIRMASS TO THE NORTH AND LESS FAVORABLE
ATMOSPHERIC CONDITIONS SHOULD KEEP ANY APPRECIABLE RAINFALL FROM
PROGRESSING MUCH FURTHER NORTH THAN THE LINE OUTLINED. MUCH OF THE
FORECAST AREA ON THE OTHER HAND WILL BE ENCOMPASSED BY THE BROAD
MID/HIGH LEVEL CLOUD SHIELD ASSOCIATED WITH THE DISTURBANCE...LIKELY
CREATING A PERIOD WITH INCREASED CLOUD COVERAGE THROUGH THE EVENING.
AS HIGHER CLOUDS DIMINISH OVERNIGHT...MODEL SOUNDINGS SUGGEST A
FAVORABLE SETUP FOR REDEVELOPMENT OF STRATUS AND POSSIBLY SOME
PATCHY FOG.
TEMPS...MAVMOS GUIDANCE LOOKED REASONABLE CONSIDERING LOW LEVEL
THERMALS AS MOST AREAS SHOULD FALL INTO THE MID 60S.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
ISSUED AT 342 PM EDT FRI AUG 9 2013
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES IN THE SOUTH SATURDAY
AND ACROSS THE ENTIRE AREA ON MONDAY.
OLD BOUNDARY SHOULD STILL BE SOMEWHERE NEAR OR JUST SOUTH OF THE
OHIO RIVER SATURDAY MORNING WITH LINGERING LOW LEVEL MOISTURE
EXTENDING NORTH INTO THE FORECAST AREA. SECONDARY FRONT DROPPING
SOUTH FROM THE GREAT LAKES LIKELY TO BE LOCATED SOMEWHERE ACROSS THE
NORTHERN PART OF THE FORECAST AREA AT 12Z. THIS FRONT WILL STEADILY
PUSH SOUTH ACROSS THE FORECAST AREA THROUGH THE DAY...EVENTUALLY
DROPPING SOUTH OF THE OHIO RIVER SATURDAY NIGHT. VERY LITTLE FORCING
ALOFT ACCOMPANYING THE BOUNDARY...BUT PRESENCE OF THE LINGERING LOW
LEVEL MOISTURE OVER SOUTHERN COUNTIES COMBINED WITH WEAK INSTABILITY
MAY BE ENOUGH TO GENERATE ISOLATED CONVECTION DURING THE AFTERNOON
AND EARLY EVENING. WILL CARRY LOW CHANCE POPS SOUTH OF A TERRE
HAUTE-RUSHVILLE LINE.
DEEPER MOISTURE PLUME WILL FINALLY DEPART TO THE SOUTH OVERNIGHT
SATURDAY AS WEAK HIGH PRESSURE BUILDS INTO THE REGION. THE HIGH WILL
REMAIN CENTERED ACROSS CENTRAL INDIANA ON SUNDAY...SQUEEZED BETWEEN
AN UPPER LEVEL DISTURBANCE TRACKING INTO THE WESTERN GREAT LAKES
AND THE BACK EDGE OF THE DEEPER MOISTURE PLUME WHICH IS LIKELY TO
NOT PROGRESS MUCH FURTHER SOUTH THAN THE TENNESSEE AND LOWER OHIO
VALLEYS. WEAK INSTABILITY SHOULD LEND TOWARDS SOME CU DEVELOPMENT IN
THE AFTERNOON BUT LACK OF ANY APPRECIABLE FORCING ALOFT SHOULD KEEP
DRY CONDITIONS IN PLACE ON SUNDAY. THE HIGH WILL SHIFT EAST SUNDAY
NIGHT WITH LOW LEVEL FLOW VEERING BACK AROUND TO A W/SW DIRECTION
MONDAY. THIS WILL ALLOW THE DEEPER MOISTURE PLUME TO ADVECT BACK
NORTH INTO THE REGION ON MONDAY AND INTERACT WITH A COLD FRONT
MOVING IN FROM THE NORTHWEST. THE COMBINATION OF PRECIP WATER VALUES
BACK UP TO 1.5-2 INCHES AND MODEST INSTABILITY SHOULD LEND TO
SCATTERED CONVECTIVE DEVELOPMENT WITH THE FRONT MONDAY AFTERNOON.
TEMPS...GENERALLY LEANED TOWARDS COOLER MAVMOS THROUGH THE PERIOD AS
THE NAM SEEMS TO BE HANGING LOW LEVEL MOISTURE UP A BIT TOO MUCH.
HIGH TEMPS SHOULD REMAIN LARGELY IN THE 80S OVER THE WEEKEND AS LOW
LEVEL THERMALS NOT NEARLY AS COOL AS WERE PROGGED JUST A FEW DAYS
AGO. EDGE WILL BE TAKEN OFF THE HUMIDITY LEVELS HOWEVER WITH COOLER
NIGHTS. POTENTIAL IS THERE FOR TEMPS TO FALL INTO THE MID AND UPPER
50S IN A NUMBER OF LOCATIONS SUNDAY MORNING.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
ISSUED AT 232 PM EDT FRI AUG 9 2013
MODELS ARE SIMILAR ENOUGH THAT THE ALLBLEND INITIALIZATION CAN BE
USED FOR MOST ITEMS IN THE LONG TERM.
AN UPPER TROUGH WILL CONTINUE ACROSS THE AREA THROUGH THE LONG TERM.
THIS WILL KEEP TEMPERATURES BELOW AVERAGE THROUGH THE PERIOD.
AS THE COLD FRONT USHERS IN THE COOL CANADIAN AIR MONDAY NIGHT INTO
TUESDAY SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE...MAINLY MONDAY
NIGHT. AFTERWARD HIGH PRESSURE WILL BUILD IN AND PROVIDE DRY
CONDITIONS TUESDAY NIGHT THROUGH FRIDAY.
&&
.AVIATION /DISCUSSION FOR THE 10/0000Z TAF ISSUANCE/...
ISSUED AT 726 PM EDT FRI AUG 9 2013
VERY SIMILAR FORECAST TONIGHT AS THE LAST SEVERAL NIGHTS AT TAF
SITES...MVFR/IFR CONDITIONS AFTER SAT 06Z AS FOG FORMS AND
CEILINGS LOWER. HOWEVER...THIS PATTERN SHOULD BREAK BY TOMORROW
NIGHT AS MUCH DRIER AIR SETTLES INTO THE REGION WITH HIGH
PRESSURE. FOG AND CEILINGS WILL LIFT AROUND MID-MORNING
TOMORROW...AND VFR CONDITIONS WILL RETURN. EXPECT VFR CONDITIONS
THIS EVENING AS WELL UNTIL THE FOG FORMS LATER TONIGHT. WINDS WILL
BE NORTHERLY AT 2 TO 8 KTS...AND THEN BECOME WESTERLY LATE IN TAF
PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....50
AVIATION...TDUD
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
438 PM EDT THU AUG 8 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 332 PM EDT THU AUG 8 2013
WEAK DIFFUSE FRONTAL BOUNDARY WILL SAG SOUTH THROUGH THE REGION INTO
FRIDAY AS SEVERAL SURFACE WAVES RIPPLE ALONG THE BOUNDARY. THIS WILL
KEEP SCATTERED SHOWERS AND THUNDERSTORMS ACROSS CENTRAL INDIANA INTO
FRIDAY...AND OVER SOUTHERN PORTIONS OF THE AREA INTO EARLY SATURDAY
AS THE FRONT MAKES ONLY SLOW PROGRESS SOUTH INTO THE TENNESSEE
VALLEY. HIGH PRESSURE DRIFTING THROUGH THE GREAT LAKES WILL BRING
DRIER AND SLIGHTLY COOLER WEATHER SATURDAY AND SUNDAY. A COLD FRONT
WILL PASS THROUGH THE AREA EARLY NEXT WEEK WITH RAIN...FOLLOWED BY
REINFORCING SHOT OF COOLER AIR BY MIDWEEK AS THE UPPER TROUGH
DEEPENS OVER THE EASTERN U S.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 332 PM EDT THU AUG 8 2013
MESOLOW RESIDES ACROSS NORTHERN COUNTIES WITH THE FRONTAL BOUNDARY
EXTENDING SOUTHWEST INTO EAST CENTRAL ILLINOIS. LINEAR CONVECTION
HAS DEVELOPED ALONG A DIFFUSE FRONT TO THE WEST OF THE INDY
METRO...WITH ADDITIONAL CONVECTION NOW BEGINNING TO DEVELOP IN
VICINITY OF THE BOUNDARY OVER SOUTH CENTRAL ILLINOIS. MUGGY
AFTERNOON IN PROGRESS AS TEMPS HAVE RISEN INTO THE MID 80S OVER ALL
BUT FAR NORTHERN COUNTIES.
COMPLEX AND LOW CONFIDENCE FORECAST FOR THE REST OF THE AFTERNOON
AND TONIGHT AS THE PRESENCE OF THE BOUNDARY SLOWLY SAGGING SOUTH
THROUGH THE FORECAST AREA AND THE APPROACHING REMNANT MCV NEAR KSTL
ARE LIKELY TO BE FACTORS IN CONVECTIVE COVERAGE INTO THE OVERNIGHT.
HRRR HANDLING CURRENT CONVECTIVE COVERAGE REASONABLY WELL AND WAS
USED AS A START FOR THE NEXT SEVERAL HOURS.
CURRENT MESOANALYSIS INDICATES AIRMASS HAS SUFFICIENTLY DESTABILIZED
ALONG AND IMMEDIATELY AHEAD OF THE BOUNDARY. MUCH OF THE CONVECTION
HAS WEAKENED WITHIN THE VICINITY OF THE WELL DEFINED MCV OVER
EASTERN MISSOURI. HOWEVER AS THIS FEATURE CONTINUES TO APPROACH
CENTRAL INDIANA OVER THE NEXT SEVERAL HOURS AND INTERACTS WITH THE
UNSTABLE AND VERY MOIST AIRMASS OVER THE REGION...EXPECT AN INCREASE
IN CONVECTIVE COVERAGE INTO THE EVENING...LIKELY CONTINUING
OVERNIGHT AS THE MCV MOVES THROUGH THE REGION. BOTH THE RAP AND 12Z
GFS HINT AT THE LOW LEVEL JET REESTABLISHING ALONG THE OHIO RIVER
TONIGHT...WITH A LOW LEVEL BAROCLINIC ZONE SETTING UP ACROSS
SOUTHERN PORTIONS OF THE FORECAST AREA. THINK ULTIMATELY SHOULD THIS
COME TO PASS...THE HEAVIEST RAINFALL WILL SET UP OVER SOUTHERN
COUNTIES OVERNIGHT AND WILL CARRY HIGHEST POPS IN THESE AREAS.
IMPRESSIVE PRECIP WATER VALUES IN EXCESS OF 2 INCHES COMBINED WITH
STORM MOTIONS UNDER 10KTS AND STEERING CURRENTS PARALLEL TO THE
BOUNDARY ARE SUPPORTIVE OF TORRENTIAL RAINFALL...BACKBUILDING AND
TRAINING ECHOES AND POTENTIAL FOR LOCALIZED FLOODING. WITH 1 HR/3 HR
FLASH FLOOD GUIDANCE VALUES IN EXCESS OF 2 INCHES/2.5-3.5 INCHES AND
UNCERTAINTY IN HOW EXTENSIVE THE PRECIP COVERAGE BECOMES...HAVE NO
PLANS TO ISSUE A FLASH FLOOD WATCH AT THIS TIME.
TEMPS...WARMER MAVMOS LOOKS REASONABLE CONSIDERING HIGH LOW LEVEL
MOISTURE PRESENT OVER THE REGION. NAM APPEARS TO BE ADVECTING DRIER
AIR INTO THE REGION TOO AGGRESSIVELY EARLY FRIDAY AND THIS IS LIKELY
IMPACTING MET GUIDANCE LOWS.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 332 PM EDT THU AUG 8 2013
FORECAST CHALLENGES REMAIN ON PRECIP CHANCES INTO EARLY SATURDAY AS
THE FRONTAL BOUNDARY MAKES ONLY SLOW PROGRESS SOUTH.
REMNANT MCV AND A WEAK SURFACE WAVE WILL BE SHIFTING EAST OF THE
REGION BY 12Z FRIDAY. FOCUS FOR ADDITIONAL CONVECTIVE DEVELOPMENT
WILL BE SOUTH OF I-70 AS THE BOUNDARY SETTLES OVER SOUTHERN INDIANA
BY FRIDAY AFTERNOON. WILL ONCE AGAIN FOCUS HIGHEST POPS OVER
SOUTHERN COUNTIES WITH LOW CHANCE POPS NORTH OF I-70 AS SLIGHTLY
DRIER AIR BEGINS TO EXPAND SOUTH FROM THE GREAT LAKES. THE BOUNDARY
WILL CONTINUE TO SHIFT SOUTH THROUGH KENTUCKY ON FRIDAY NIGHT AS AN
UPPER LOW PIVOTS SOUTH OF JAMES BAY AND INTRODUCES A BROAD UPPER
LEVEL TROUGH OVER THE EASTERN U S. WILL HANG ONTO LOW CHANCE POPS
OVER SOUTHERN COUNTIES FRIDAY NIGHT AND EARLY SATURDAY DUE TO THE
CLOSE PROXIMITY OF THE BOUNDARY...BUT OVERALL TREND INTO SATURDAY
SHOULD BE TOWARDS DRIER AND SLIGHTLY COOLER AIR EXPANDING INTO THE
FORECAST AREA AS THE DEEPER MOISTURE IS PUSHED SOUTH.
SURFACE HIGH PRESSURE WILL BUILD ACROSS THE LOWER GREAT LAKES
SATURDAY AFTERNOON THROUGH SUNDAY WITH DRY WEATHER. LOW LEVEL
MOISTURE ATTEMPTS TO IMMEDIATELY RETURN BACK NORTH INTO THE OHIO
VALLEY SUNDAY AFTERNOON AS THE HIGH SHIFTS AWAY TO THE EAST. HAVE
KEPT DRY CONDITIONS THROUGH 00Z MONDAY AS LITTLE FORCING ALOFT
PRESENT...ALTHOUGH WILL HAVE TO MONITOR FOR ISOLATED SHOWERS OVER
THE LOWER WABASH VALLEY AS INSTABILITY AXIS WILL BE CLOSE BY ACROSS
THE LOWER OHIO VALLEY.
TEMPS...MOS GUIDANCE IN GENERAL WORKS WELL CONSIDERING LOW LEVEL
THERMALS THROUGHOUT THE PERIOD. HIGH TEMPS FRIDAY AND SATURDAY WILL
BE HIGHLY DEPENDENT ON CLOUD COVER...BUT GENERALLY LOOKING AT LOW TO
MID 80S BOTH DAYS...SLIGHTLY COOLER WHERE RAIN/CLOUDS IMPACT. CORE
OF THE COOLER AIR ASSOCIATED WITH THE UPPER TROUGH LIKELY DELAYED TO
SUNDAY AS 850MB TEMPS FALL TO AROUND 11C. LOCATIONS SUNDAY SHOULD
REMAIN IN THE UPPER 70S AND LOWER 80S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 229 PM EDT THU AUG 8 2013
MODELS ARE SIMILAR ENOUGH THAT THE ALLBLEND INITIALIZATION CAN BE
USED FOR MOST ITEMS IN THE LONG TERM.
UPPER TROUGH WILL DEEPEN ACROSS THE AREA IN THE EXTENDED. THIS WILL
KEEP CENTRAL INDIANA IN COOLER NORTHWEST FLOW. TEMPERATURES WILL
REMAIN BELOW AVERAGE THROUGH THE PERIOD.
A COLD FRONT WILL WORK ITS WAY SOUTH MONDAY INTO TUESDAY BRINGING
THE COOLER AIR TO THE AREA. MODELS AND SOME ENSEMBLES ARE SHOWING
CHANCES FOR RAIN LINGERING INTO TUESDAY WITH SOME TIMING DIFFERENCES
BETWEEN THEM. GIVEN THE UNCERTAINTIES INVOLVED WILL GO WITH
ALLBLEND/S CHANCES FOR RAIN MONDAY INTO TUESDAY...BUT AT THE MOMENT
&&
.AVIATION /DISCUSSION FOR THE 08/2100Z TAF UPDATE/...
ISSUED AT 431 PM EDT THU AUG 8 2013
UPDATE...
SCATTERED SHOWERS AND THUNDERSTORMS WILL IMPACT TAF SITES INTO
EARLY EVENING...CAUSING PERIODS OF MVFR/IFR CONDITIONS.
PREVIOUS DISCUSSION...
LOW CONFIDENCE FORECAST...BUT GENERALLY VFR CONDITIONS GIVING WAY
TO MVFR CONDITIONS OVERNIGHT WITH POTENTIAL FOR IFR. SCATTERED
CONVECTION AROUND THROUGH THE PERIOD...ALONG WITH VARIABLE WINDS.
WEAK BOUNDARY WILL REMAIN ACROSS CENTRAL INDIANA THIS AFTERNOON...
MAKING WINDS VARIABLE. SCATTERED CONVECTION WILL PERSIST AROUND
THIS BOUNDARY...BUT AT THE MOMENT IT APPEARS ORGANIZED CONVECTION
WILL REMAIN OUT OF THE AREA. ANY CEILINGS BELOW MVFR SHOULD LIFT
TO VFR BY VALID TIME EXCEPT FOR KLAF WHERE THEY WILL LINGER.
DURING THE NIGHT...THREAT FOR CONVECTION WILL CONTINUE BUT AT THE
MOMENT DO NOT EXPECT WIDESPREAD CONVECTION /ALTHOUGH SOME MODELS
INDICATE THIS POSSIBILITY...BUT ODDS ARE LOW WITHOUT ANY
SIGNIFICANT FORCING NEARBY/. MOIST AIRMASS WILL LEAD TO MVFR
VISIBILITIES/CEILINGS WITH POTENTIAL FOR IFR. THESE SHOULD IMPROVE
ON FRIDAY WITH DRIER AIR WORKING IN AS BOUNDARY SHIFTS FARTHER
SOUTH.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....50
AVIATION...50/TDUD
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
332 PM EDT THU AUG 8 2013
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED
BELOW.
&&
.SYNOPSIS...
ISSUED AT 332 PM EDT THU AUG 8 2013
WEAK DIFFUSE FRONTAL BOUNDARY WILL SAG SOUTH THROUGH THE REGION INTO
FRIDAY AS SEVERAL SURFACE WAVES RIPPLE ALONG THE BOUNDARY. THIS WILL
KEEP SCATTERED SHOWERS AND THUNDERSTORMS ACROSS CENTRAL INDIANA INTO
FRIDAY...AND OVER SOUTHERN PORTIONS OF THE AREA INTO EARLY SATURDAY
AS THE FRONT MAKES ONLY SLOW PROGRESS SOUTH INTO THE TENNESSEE
VALLEY. HIGH PRESSURE DRIFTING THROUGH THE GREAT LAKES WILL BRING
DRIER AND SLIGHTLY COOLER WEATHER SATURDAY AND SUNDAY. A COLD FRONT
WILL PASS THROUGH THE AREA EARLY NEXT WEEK WITH RAIN...FOLLOWED BY
REINFORCING SHOT OF COOLER AIR BY MIDWEEK AS THE UPPER TROUGH
DEEPENS OVER THE EASTERN U S.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 332 PM EDT THU AUG 8 2013
MESOLOW RESIDES ACROSS NORTHERN COUNTIES WITH THE FRONTAL BOUNDARY
EXTENDING SOUTHWEST INTO EAST CENTRAL ILLINOIS. LINEAR CONVECTION
HAS DEVELOPED ALONG A DIFFUSE FRONT TO THE WEST OF THE INDY
METRO...WITH ADDITIONAL CONVECTION NOW BEGINNING TO DEVELOP IN
VICINITY OF THE BOUNDARY OVER SOUTH CENTRAL ILLINOIS. MUGGY
AFTERNOON IN PROGRESS AS TEMPS HAVE RISEN INTO THE MID 80S OVER ALL
BUT FAR NORTHERN COUNTIES.
COMPLEX AND LOW CONFIDENCE FORECAST FOR THE REST OF THE AFTERNOON
AND TONIGHT AS THE PRESENCE OF THE BOUNDARY SLOWLY SAGGING SOUTH
THROUGH THE FORECAST AREA AND THE APPROACHING REMNANT MCV NEAR KSTL
ARE LIKELY TO BE FACTORS IN CONVECTIVE COVERAGE INTO THE OVERNIGHT.
HRRR HANDLING CURRENT CONVECTIVE COVERAGE REASONABLY WELL AND WAS
USED AS A START FOR THE NEXT SEVERAL HOURS.
CURRENT MESOANALYSIS INDICATES AIRMASS HAS SUFFICIENTLY DESTABILIZED
ALONG AND IMMEDIATELY AHEAD OF THE BOUNDARY. MUCH OF THE CONVECTION
HAS WEAKENED WITHIN THE VICINITY OF THE WELL DEFINED MCV OVER
EASTERN MISSOURI. HOWEVER AS THIS FEATURE CONTINUES TO APPROACH
CENTRAL INDIANA OVER THE NEXT SEVERAL HOURS AND INTERACTS WITH THE
UNSTABLE AND VERY MOIST AIRMASS OVER THE REGION...EXPECT AN INCREASE
IN CONVECTIVE COVERAGE INTO THE EVENING...LIKELY CONTINUING
OVERNIGHT AS THE MCV MOVES THROUGH THE REGION. BOTH THE RAP AND 12Z
GFS HINT AT THE LOW LEVEL JET REESTABLISHING ALONG THE OHIO RIVER
TONIGHT...WITH A LOW LEVEL BAROCLINIC ZONE SETTING UP ACROSS
SOUTHERN PORTIONS OF THE FORECAST AREA. THINK ULTIMATELY SHOULD THIS
COME TO PASS...THE HEAVIEST RAINFALL WILL SET UP OVER SOUTHERN
COUNTIES OVERNIGHT AND WILL CARRY HIGHEST POPS IN THESE AREAS.
IMPRESSIVE PRECIP WATER VALUES IN EXCESS OF 2 INCHES COMBINED WITH
STORM MOTIONS UNDER 10KTS AND STEERING CURRENTS PARALLEL TO THE
BOUNDARY ARE SUPPORTIVE OF TORRENTIAL RAINFALL...BACKBUILDING AND
TRAINING ECHOES AND POTENTIAL FOR LOCALIZED FLOODING. WITH 1 HR/3 HR
FLASH FLOOD GUIDANCE VALUES IN EXCESS OF 2 INCHES/2.5-3.5 INCHES AND
UNCERTAINTY IN HOW EXTENSIVE THE PRECIP COVERAGE BECOMES...HAVE NO
PLANS TO ISSUE A FLASH FLOOD WATCH AT THIS TIME.
TEMPS...WARMER MAVMOS LOOKS REASONABLE CONSIDERING HIGH LOW LEVEL
MOISTURE PRESENT OVER THE REGION. NAM APPEARS TO BE ADVECTING DRIER
AIR INTO THE REGION TOO AGGRESSIVELY EARLY FRIDAY AND THIS IS LIKELY
IMPACTING MET GUIDANCE LOWS.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 332 PM EDT THU AUG 8 2013
FORECAST CHALLENGES REMAIN ON PRECIP CHANCES INTO EARLY SATURDAY AS
THE FRONTAL BOUNDARY MAKES ONLY SLOW PROGRESS SOUTH.
REMNANT MCV AND A WEAK SURFACE WAVE WILL BE SHIFTING EAST OF THE
REGION BY 12Z FRIDAY. FOCUS FOR ADDITIONAL CONVECTIVE DEVELOPMENT
WILL BE SOUTH OF I-70 AS THE BOUNDARY SETTLES OVER SOUTHERN INDIANA
BY FRIDAY AFTERNOON. WILL ONCE AGAIN FOCUS HIGHEST POPS OVER
SOUTHERN COUNTIES WITH LOW CHANCE POPS NORTH OF I-70 AS SLIGHTLY
DRIER AIR BEGINS TO EXPAND SOUTH FROM THE GREAT LAKES. THE BOUNDARY
WILL CONTINUE TO SHIFT SOUTH THROUGH KENTUCKY ON FRIDAY NIGHT AS AN
UPPER LOW PIVOTS SOUTH OF JAMES BAY AND INTRODUCES A BROAD UPPER
LEVEL TROUGH OVER THE EASTERN U S. WILL HANG ONTO LOW CHANCE POPS
OVER SOUTHERN COUNTIES FRIDAY NIGHT AND EARLY SATURDAY DUE TO THE
CLOSE PROXIMITY OF THE BOUNDARY...BUT OVERALL TREND INTO SATURDAY
SHOULD BE TOWARDS DRIER AND SLIGHTLY COOLER AIR EXPANDING INTO THE
FORECAST AREA AS THE DEEPER MOISTURE IS PUSHED SOUTH.
SURFACE HIGH PRESSURE WILL BUILD ACROSS THE LOWER GREAT LAKES
SATURDAY AFTERNOON THROUGH SUNDAY WITH DRY WEATHER. LOW LEVEL
MOISTURE ATTEMPTS TO IMMEDIATELY RETURN BACK NORTH INTO THE OHIO
VALLEY SUNDAY AFTERNOON AS THE HIGH SHIFTS AWAY TO THE EAST. HAVE
KEPT DRY CONDITIONS THROUGH 00Z MONDAY AS LITTLE FORCING ALOFT
PRESENT...ALTHOUGH WILL HAVE TO MONITOR FOR ISOLATED SHOWERS OVER
THE LOWER WABASH VALLEY AS INSTABILITY AXIS WILL BE CLOSE BY ACROSS
THE LOWER OHIO VALLEY.
TEMPS...MOS GUIDANCE IN GENERAL WORKS WELL CONSIDERING LOW LEVEL
THERMALS THROUGHOUT THE PERIOD. HIGH TEMPS FRIDAY AND SATURDAY WILL
BE HIGHLY DEPENDENT ON CLOUD COVER...BUT GENERALLY LOOKING AT LOW TO
MID 80S BOTH DAYS...SLIGHTLY COOLER WHERE RAIN/CLOUDS IMPACT. CORE
OF THE COOLER AIR ASSOCIATED WITH THE UPPER TROUGH LIKELY DELAYED TO
SUNDAY AS 850MB TEMPS FALL TO AROUND 11C. LOCATIONS SUNDAY SHOULD
REMAIN IN THE UPPER 70S AND LOWER 80S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 229 PM EDT THU AUG 8 2013
MODELS ARE SIMILAR ENOUGH THAT THE ALLBLEND INITIALIZATION CAN BE
USED FOR MOST ITEMS IN THE LONG TERM.
UPPER TROUGH WILL DEEPEN ACROSS THE AREA IN THE EXTENDED. THIS WILL
KEEP CENTRAL INDIANA IN COOLER NORTHWEST FLOW. TEMPERATURES WILL
REMAIN BELOW AVERAGE THROUGH THE PERIOD.
A COLD FRONT WILL WORK ITS WAY SOUTH MONDAY INTO TUESDAY BRINGING
THE COOLER AIR TO THE AREA. MODELS AND SOME ENSEMBLES ARE SHOWING
CHANCES FOR RAIN LINGERING INTO TUESDAY WITH SOME TIMING DIFFERENCES
BETWEEN THEM. GIVEN THE UNCERTAINTIES INVOLVED WILL GO WITH
ALLBLEND/S CHANCES FOR RAIN MONDAY INTO TUESDAY...BUT AT THE MOMENT
&&
.AVIATION /DISCUSSION FOR THE 081800Z TAF ISSUANCE/...
ISSUED AT 100 PM EDT THU AUG 8 2013
LOW CONFIDENCE FORECAST...BUT GENERALLY VFR CONDITIONS GIVING WAY TO
MVFR CONDITIONS OVERNIGHT WITH POTENTIAL FOR IFR. SCATTERED
CONVECTION AROUND THROUGH THE PERIOD...ALONG WITH VARIABLE WINDS.
WEAK BOUNDARY WILL REMAIN ACROSS CENTRAL INDIANA THIS
AFTERNOON...MAKING WINDS VARIABLE. SCATTERED CONVECTION WILL PERSIST
AROUND THIS BOUNDARY...BUT AT THE MOMENT IT APPEARS ORGANIZED
CONVECTION WILL REMAIN OUT OF THE AREA. ANY CEILINGS BELOW MVFR
SHOULD LIFT TO VFR BY VALID TIME EXCEPT FOR KLAF WHERE THEY WILL
LINGER.
DURING THE NIGHT THREAT FOR CONVECTION WILL CONTINUE BUT AT THE
MOMENT DO NOT EXPECT WIDESPREAD CONVECTION /ALTHOUGH SOME MODELS
INDICATE THIS POSSIBILITY...BUT ODDS ARE LOW WITHOUT ANY SIGNIFICANT
FORCING NEARBY/. MOIST AIRMASS WILL LEAD TO MVFR
VISIBILITIES/CEILINGS WITH POTENTIAL FOR IFR. THESE SHOULD IMPROVE
ON FRIDAY WITH DRIER AIR WORKING IN AS BOUNDARY SHIFTS FARTHER SOUTH.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....50
AVIATION...50
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
229 PM EDT THU AUG 8 2013
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 210 AM EDT THU AUG 8 2013
WARM AND HUMID AIR WILL REMAIN OVER INDIANA FOR THE NEXT FEW DAYS
AS A FRONTAL BOUNDARY LINGERS ACROSS SOUTHERN INDIANA. CHANCES FOR
SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH FRIDAY NIGHT AS
SEVERAL UPPER LEVEL WEATHER DISTURBANCES PUSH INTO THE OHIO VALLEY.
DRY AND LESS HUMID WEATHER WILL ARRIVE SATURDAY AS HIGH PRESSURE
FROM CANADA BUILDS ACROSS THE REGION.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1003 AM EDT THU AUG 8 2013
LOW STRATUS STUBBORNLY HANGING ON ACROSS A GOOD PORTION OF THE
FORECAST AREA...WITH CLOUDS HAVING ACTUALLY INCREASED IN COVERAGE
OVER NORTHERN COUNTIES SINCE 12Z. SCATTERED CONVECTION HAS ALSO
DEVELOPED OVER THE NORTHERN WABASH VALLEY OVER THE LAST HOUR OR
SO. 13Z SURFACE ANALYSIS PLACES THE WEAK REMNANT BOUNDARY ACROSS
THE FORECAST AREA...ROUGHLY EXTENDING FROM NEAR RICHMOND W/SW TO
JUST SOUTH OF THE INDY METRO AND KHUF. MUGGY MORNING WITH TEMPS
MAINLY IN THE 70S.
COMPLEX FORECAST FOR THE REMAINDER OF THE DAY AS CONVECTION HAS
DEVELOPED SOONER THAN ANTICIPATED. VERY WEAK FORCING ALOFT WITHIN
A POORLY DEFINED UPPER TROUGH COMBINED WITH AN AREA OF LOW LEVEL
MOISTURE CONVERGENCE APPEAR TO BE CONTRIBUTING TO THE CONVECTIVE
DEVELOPMENT NORTHWEST OF INDY THIS MORNING. HRRR GUIDANCE IS
CAPTURING THIS TO SOME DEGREE...AND TRENDS TOWARDS FURTHER
CONVECTIVE DEVELOPMENT ACROSS THE FORECAST AREA INTO THE
AFTERNOON. CONSIDERING INCREASING INSTABILITY OVER THE NEXT FEW
HOURS COMBINED WITH THE DEEP LOW LEVEL MOISTURE PRESENT...WEAK
FORCING ALOFT AND THE PRESENCE OF THE BOUNDARY ACROSS THE
REGION...REALLY HARD TO ARGUE WITH THIS SCENARIO AT THIS POINT.
BUMPED UP POPS TO BEGIN NORTHWEST OF INDY NOW...THEN INCREASE TO
30-50 POPS OVER ENTIRE FORECAST AREA FOR THE AFTERNOON. MENTIONING
ONLY ISOLATED THUNDER THROUGH MIDDAY AS MESOANALYSIS SHOWS LITTLE
INSTABILITY PRESENT RIGHT NOW. EXPECT A BETTER CHANCE FOR THUNDER
THIS AFTERNOON AS INSTABILITY INCREASES WITH DIURNAL HEATING.
WHILE THERE ARE BREAKS IN THE CLOUD COVER THIS MORNING...
ESPECIALLY OVER SOUTHERN COUNTIES...HAVE INCREASED CLOUD COVERAGE
FOR THE AFTERNOON AS CU LIKELY TO FILL IN AS CONVECTIVE TEMPS ARE
MET. ADDITIONALLY...CLOUD DEBRIS FROM WEAKENING MCS OVER THE
OZARKS POISED TO EXPAND INTO THE REGION THIS AFTERNOON. WITH THE
INCREASE IN CLOUDS...DROPPED HIGH TEMPS A COUPLE DEGREES AS WELL.
ZONE AND GRID UPDATES OUT SHORTLY.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 210 AM EDT THU AUG 8 2013
LITTLE CHANGE APPEARS IN THE OVERALL PATTERN THROUGH FRIDAY
AFTERNOON. GFS AND NAM CONTINUE TO SUGGEST WEAK...POORLY ORGANIZED
SHORT WAVES PUSHING THROUGH THE FLOW ALOFT. MEANWHILE THE FRONTAL
BOUNDARY LINGERS NEAR THE OHIO VALLEY. 310K GFS ISENTROPIC SURFACE
FAILS TO SHOW MUCH IN THE WAY OF LIFT...BUT DOES MANAGE TO
ILLUSTRATE THE VERY MOIST AIR MASS ACROSS THE AREA SHOWING
SPECIFIC HUMIDITIES IN EXCESS OF 4 G/KG ON FRIDAY. FORECAST
SOUNDINGS THROUGH FRIDAY SHOW LESS FAVORABLE LAPSE RATES WITH
LESS CAPE THAN TODAY. HOWEVER WITH THE MOIST FLOW ALOFT...MOIST
AIR IN PLACE AT THE SURFACE AND UNCERTAINTY REMAINING WITH ANY
EMBEDDED SHORT WAVES WILL CONTINUE TO KEEP LOW CHC POPS TONIGHT
AND AGAIN ON FRIDAY. WILL TREND LOWS WARMER THAN MAVMOS AND STICK
CLOSE ON HIGHS FOR FRIDAY.
ON FRIDAY NIGHT THE GFS AND NAM BOTH SUGGEST A STRONG SHORT WAVE
ALOFT SWEEPING THROUGH THE FLOW. TIME HEIGHT SECTIONS BEGIN TO
SHOW MORE VV WHILE THE NAM SOUNDINGS SHOW DEEP SATURATION. THE GFS
IS MUCH LESS AGGRESSIVE WITH SATURATION...BUT STILL DOES SHOW THE
MAIN WAVE ALOFT. MEANWHILE GFS 310K ISENTROPIC SURFACE SHOWS
MINIMAL LIFT...BUT A VERY MOIST AIR MASS IN PLACE WITH SPECIFIC
HUMIDITIES OVER 5 G/KG AGAIN. IN THE LOWER LEVELS...BEST
CONVERGENCE REMAINS NEAR THE FRONT...LINGERING NEAR THE OHIO
RIVER. THUS WILL USE A BLEND OF THE LOW GFS POPS AND THE HIGHER
NAM POPS FOR FRIDAY NIGHT.
A MUCH DIFFERENT AIR MASS ARRIVES ON SATURDAY AND SATURDAY NIGHT
AS HIGH PRESSURE BUILDS ACROSS THE AREA FROM CANADA. FORECAST
SOUNDINGS AGREE AS THE COLUMN DRIES OUT DRAMATICALLY AMID
SUBSIDENCE. CONVECTIVE TEMPERATURES LOOK QUITE REACHABLE WITH A
MID LEVEL CAP IN PLACE...THUS EXPECTED SOME AFTERNOON CU ON
SATURDAY AND MOSTLY CLEAR SKIES THAT NIGHT. GIVEN THE FORECAST
SOUNDINGS WILL TREND HIGHS ON SATURDAY COOLER THAN MAVMOS AND
STICK CLOSE ON LOWS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 229 PM EDT THU AUG 8 2013
MODELS ARE SIMILAR ENOUGH THAT THE ALLBLEND INITIALIZATION CAN BE
USED FOR MOST ITEMS IN THE LONG TERM.
UPPER TROUGH WILL DEEPEN ACROSS THE AREA IN THE EXTENDED. THIS WILL
KEEP CENTRAL INDIANA IN COOLER NORTHWEST FLOW. TEMPERATURES WILL
REMAIN BELOW AVERAGE THROUGH THE PERIOD.
A COLD FRONT WILL WORK ITS WAY SOUTH MONDAY INTO TUESDAY BRINGING
THE COOLER AIR TO THE AREA. MODELS AND SOME ENSEMBLES ARE SHOWING
CHANCES FOR RAIN LINGERING INTO TUESDAY WITH SOME TIMING DIFFERENCES
BETWEEN THEM. GIVEN THE UNCERTAINTIES INVOLVED WILL GO WITH
ALLBLEND/S CHANCES FOR RAIN MONDAY INTO TUESDAY...BUT AT THE MOMENT
FEEL THAT BEST CHANCES WILL BE LATER ON MONDAY INTO MONDAY NIGHT.
&&
.AVIATION /DISCUSSION FOR THE 081800Z TAF ISSUANCE/...
ISSUED AT 100 PM EDT THU AUG 8 2013
LOW CONFIDENCE FORECAST...BUT GENERALLY VFR CONDITIONS GIVING WAY TO
MVFR CONDITIONS OVERNIGHT WITH POTENTIAL FOR IFR. SCATTERED
CONVECTION AROUND THROUGH THE PERIOD...ALONG WITH VARIABLE WINDS.
WEAK BOUNDARY WILL REMAIN ACROSS CENTRAL INDIANA THIS
AFTERNOON...MAKING WINDS VARIABLE. SCATTERED CONVECTION WILL PERSIST
AROUND THIS BOUNDARY...BUT AT THE MOMENT IT APPEARS ORGANIZED
CONVECTION WILL REMAIN OUT OF THE AREA. ANY CEILINGS BELOW MVFR
SHOULD LIFT TO VFR BY VALID TIME EXCEPT FOR KLAF WHERE THEY WILL
LINGER.
DURING THE NIGHT THREAT FOR CONVECTION WILL CONTINUE BUT AT THE
MOMENT DO NOT EXPECT WIDESPREAD CONVECTION /ALTHOUGH SOME MODELS
INDICATE THIS POSSIBILITY...BUT ODDS ARE LOW WITHOUT ANY SIGNIFICANT
FORCING NEARBY/. MOIST AIRMASS WILL LEAD TO MVFR
VISIBILITIES/CEILINGS WITH POTENTIAL FOR IFR. THESE SHOULD IMPROVE
ON FRIDAY WITH DRIER AIR WORKING IN AS BOUNDARY SHIFTS FARTHER SOUTH.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...RYAN
SHORT TERM...PUMA
LONG TERM....50
AVIATION...50
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1032 AM EDT THU AUG 8 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 210 AM EDT THU AUG 8 2013
WARM AND HUMID AIR WILL REMAIN OVER INDIANA FOR THE NEXT FEW DAYS
AS A FRONTAL BOUNDARY LINGERS ACROSS SOUTHERN INDIANA. CHANCES FOR
SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH FRIDAY NIGHT AS
SEVERAL UPPER LEVEL WEATHER DISTURBANCES PUSH INTO THE OHIO VALLEY.
DRY AND LESS HUMID WEATHER WILL ARRIVE SATURDAY AS HIGH PRESSURE
FROM CANADA BUILDS ACROSS THE REGION.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1003 AM EDT THU AUG 8 2013
LOW STRATUS STUBBORNLY HANGING ON ACROSS A GOOD PORTION OF THE
FORECAST AREA...WITH CLOUDS HAVING ACTUALLY INCREASED IN COVERAGE
OVER NORTHERN COUNTIES SINCE 12Z. SCATTERED CONVECTION HAS ALSO
DEVELOPED OVER THE NORTHERN WABASH VALLEY OVER THE LAST HOUR OR
SO. 13Z SURFACE ANALYSIS PLACES THE WEAK REMNANT BOUNDARY ACROSS
THE FORECAST AREA...ROUGHLY EXTENDING FROM NEAR RICHMOND W/SW TO
JUST SOUTH OF THE INDY METRO AND KHUF. MUGGY MORNING WITH TEMPS
MAINLY IN THE 70S.
COMPLEX FORECAST FOR THE REMAINDER OF THE DAY AS CONVECTION HAS
DEVELOPED SOONER THAN ANTICIPATED. VERY WEAK FORCING ALOFT WITHIN
A POORLY DEFINED UPPER TROUGH COMBINED WITH AN AREA OF LOW LEVEL
MOISTURE CONVERGENCE APPEAR TO BE CONTRIBUTING TO THE CONVECTIVE
DEVELOPMENT NORTHWEST OF INDY THIS MORNING. HRRR GUIDANCE IS
CAPTURING THIS TO SOME DEGREE...AND TRENDS TOWARDS FURTHER
CONVECTIVE DEVELOPMENT ACROSS THE FORECAST AREA INTO THE
AFTERNOON. CONSIDERING INCREASING INSTABILITY OVER THE NEXT FEW
HOURS COMBINED WITH THE DEEP LOW LEVEL MOISTURE PRESENT...WEAK
FORCING ALOFT AND THE PRESENCE OF THE BOUNDARY ACROSS THE
REGION...REALLY HARD TO ARGUE WITH THIS SCENARIO AT THIS POINT.
BUMPED UP POPS TO BEGIN NORTHWEST OF INDY NOW...THEN INCREASE TO
30-50 POPS OVER ENTIRE FORECAST AREA FOR THE AFTERNOON. MENTIONING
ONLY ISOLATED THUNDER THROUGH MIDDAY AS MESOANALYSIS SHOWS LITTLE
INSTABILITY PRESENT RIGHT NOW. EXPECT A BETTER CHANCE FOR THUNDER
THIS AFTERNOON AS INSTABILITY INCREASES WITH DIURNAL HEATING.
WHILE THERE ARE BREAKS IN THE CLOUD COVER THIS MORNING...
ESPECIALLY OVER SOUTHERN COUNTIES...HAVE INCREASED CLOUD COVERAGE
FOR THE AFTERNOON AS CU LIKELY TO FILL IN AS CONVECTIVE TEMPS ARE
MET. ADDITIONALLY...CLOUD DEBRIS FROM WEAKENING MCS OVER THE
OZARKS POISED TO EXPAND INTO THE REGION THIS AFTERNOON. WITH THE
INCREASE IN CLOUDS...DROPPED HIGH TEMPS A COUPLE DEGREES AS WELL.
ZONE AND GRID UPDATES OUT SHORTLY.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 210 AM EDT THU AUG 8 2013
LITTLE CHANGE APPEARS IN THE OVERALL PATTERN THROUGH FRIDAY
AFTERNOON. GFS AND NAM CONTINUE TO SUGGEST WEAK...POORLY ORGANIZED
SHORT WAVES PUSHING THROUGH THE FLOW ALOFT. MEANWHILE THE FRONTAL
BOUNDARY LINGERS NEAR THE OHIO VALLEY. 310K GFS ISENTROPIC SURFACE
FAILS TO SHOW MUCH IN THE WAY OF LIFT...BUT DOES MANAGE TO
ILLUSTRATE THE VERY MOIST AIR MASS ACROSS THE AREA SHOWING
SPECIFIC HUMIDITIES IN EXCESS OF 4 G/KG ON FRIDAY. FORECAST
SOUNDINGS THROUGH FRIDAY SHOW LESS FAVORABLE LAPSE RATES WITH
LESS CAPE THAN TODAY. HOWEVER WITH THE MOIST FLOW ALOFT...MOIST
AIR IN PLACE AT THE SURFACE AND UNCERTAINTY REMAINING WITH ANY
EMBEDDED SHORT WAVES WILL CONTINUE TO KEEP LOW CHC POPS TONIGHT
AND AGAIN ON FRIDAY. WILL TREND LOWS WARMER THAN MAVMOS AND STICK
CLOSE ON HIGHS FOR FRIDAY.
ON FRIDAY NIGHT THE GFS AND NAM BOTH SUGGEST A STRONG SHORT WAVE
ALOFT SWEEPING THROUGH THE FLOW. TIME HEIGHT SECTIONS BEGIN TO
SHOW MORE VV WHILE THE NAM SOUNDINGS SHOW DEEP SATURATION. THE GFS
IS MUCH LESS AGGRESSIVE WITH SATURATION...BUT STILL DOES SHOW THE
MAIN WAVE ALOFT. MEANWHILE GFS 310K ISENTROPIC SURFACE SHOWS
MINIMAL LIFT...BUT A VERY MOIST AIR MASS IN PLACE WITH SPECIFIC
HUMIDITIES OVER 5 G/KG AGAIN. IN THE LOWER LEVELS...BEST
CONVERGENCE REMAINS NEAR THE FRONT...LINGERING NEAR THE OHIO
RIVER. THUS WILL USE A BLEND OF THE LOW GFS POPS AND THE HIGHER
NAM POPS FOR FRIDAY NIGHT.
A MUCH DIFFERENT AIR MASS ARRIVES ON SATURDAY AND SATURDAY NIGHT
AS HIGH PRESSURE BUILDS ACROSS THE AREA FROM CANADA. FORECAST
SOUNDINGS AGREE AS THE COLUMN DRIES OUT DRAMATICALLY AMID
SUBSIDENCE. CONVECTIVE TEMPERATURES LOOK QUITE REACHABLE WITH A
MID LEVEL CAP IN PLACE...THUS EXPECTED SOME AFTERNOON CU ON
SATURDAY AND MOSTLY CLEAR SKIES THAT NIGHT. GIVEN THE FORECAST
SOUNDINGS WILL TREND HIGHS ON SATURDAY COOLER THAN MAVMOS AND
STICK CLOSE ON LOWS.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
ISSUED AT 230 AM EDT THU AUG 8 2013
LONG TERM PERIOD CONTINUES TO BE CHARACTERIZED BY ZONAL TO
MODERATELY CYCLONIC FLOW...SUGGESTING TEMPERATURES NEAR TO A FEW
DEGREES BELOW NORMAL. INITIALIZATION HANDLES THIS WELL AND FEW
CHANGES REQUIRED.
DID CONFINE ONLY SLIGHT CHANCE POPS TO MONDAY AS GFS SUGGESTS A
WEAK FRONTAL PASSAGE WHICH COULD POP A SHOWER OR ISOLATED STORM.
BEYOND MONDAY...IN OTHER PERIODS POPS ARE NOT MERITED...AND WERE
REMOVED.
&&
.AVIATION /DISCUSSION FOR THE 081500Z TAF UPDATE/...
ISSUED AT 1032 AM EDT THU AUG 8 2013
LOW LEVEL STRATUS HAS BROKEN UP...BUT ADDITIONAL CLOUDS AROUND
5000FT HAVE DEVELOPED. A WEAK SURFACE TROUGH WILL CONTINUE TO
MEANDER NEAR KIND FOR THE NEXT FEW HOURS...KEEPING WINDS VARIABLE IN
DIRECTION. SCATTERED SHOWERS WILL CONTINUE TO POP-UP AS WELL...SO
ADDED VCSH. CANNOT RULE OUT MVFR CONDITIONS IN SHOWERS.
PREVIOUS DISCUSSION FOLLOWS...
SO FAR THIS MORNING...IND HAS MADE IT TO IFR BUT OTHER SITES HAVE
ONLY FLIRTED WITH MVFR. ANY RESTRICTIONS SHOULD END BY MID
MORNING...WITH BROKEN VFR STRATOCU REPLACING THEM.
CANNOT ENTIRELY RULE OUT A FEW SHOWERS OR STORMS TODAY...BUT WITH
MAJOR UNCERTAINTY IN TIMING AND PLACEMENT...CANNOT MENTION RIGHT NOW.
LATE IN THE PERIOD...GUIDANCE WANTS TO REDEVELOP
RESTRICTIONS...QUITE LOW IN SOME SPOTS. LAMP WAS SIGNIFICANTLY
OVERAGGRESSIVE TONIGHT...SO WILL LEAVE ANY MENTION OF RESTRICTIONS
OUT FOR NOW EXCEPT AT BMG...WHICH IS ONE OF THE FOGGIER SITES AND
WILL BE A BIT CLOSER TO THE BOUNDARY AND IN A SLIGHTLY RICHER
AIRMASS.
WINDS WILL BE BELOW 10KT THROUGHOUT THE PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...RYAN
SHORT TERM...PUMA
LONG TERM....NIELD
AVIATION...NIELD/50
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1003 AM EDT THU AUG 8 2013
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 210 AM EDT THU AUG 8 2013
WARM AND HUMID AIR WILL REMAIN OVER INDIANA FOR THE NEXT FEW DAYS
AS A FRONTAL BOUNDARY LINGERS ACROSS SOUTHERN INDIANA. CHANCES FOR
SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH FRIDAY NIGHT AS
SEVERAL UPPER LEVEL WEATHER DISTURBANCES PUSH INTO THE OHIO VALLEY.
DRY AND LESS HUMID WEATHER WILL ARRIVE SATURDAY AS HIGH PRESSURE
FROM CANADA BUILDS ACROSS THE REGION.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1003 AM EDT THU AUG 8 2013
LOW STRATUS STUBBORNLY HANGING ON ACROSS A GOOD PORTION OF THE
FORECAST AREA...WITH CLOUDS HAVING ACTUALLY INCREASED IN COVERAGE
OVER NORTHERN COUNTIES SINCE 12Z. SCATTERED CONVECTION HAS ALSO
DEVELOPED OVER THE NORTHERN WABASH VALLEY OVER THE LAST HOUR OR
SO. 13Z SURFACE ANALYSIS PLACES THE WEAK REMNANT BOUNDARY ACROSS
THE FORECAST AREA...ROUGHLY EXTENDING FROM NEAR RICHMOND W/SW TO
JUST SOUTH OF THE INDY METRO AND KHUF. MUGGY MORNING WITH TEMPS
MAINLY IN THE 70S.
COMPLEX FORECAST FOR THE REMAINDER OF THE DAY AS CONVECTION HAS
DEVELOPED SOONER THAN ANTICIPATED. VERY WEAK FORCING ALOFT WITHIN
A POORLY DEFINED UPPER TROUGH COMBINED WITH AN AREA OF LOW LEVEL
MOISTURE CONVERGENCE APPEAR TO BE CONTRIBUTING TO THE CONVECTIVE
DEVELOPMENT NORTHWEST OF INDY THIS MORNING. HRRR GUIDANCE IS
CAPTURING THIS TO SOME DEGREE...AND TRENDS TOWARDS FURTHER
CONVECTIVE DEVELOPMENT ACROSS THE FORECAST AREA INTO THE
AFTERNOON. CONSIDERING INCREASING INSTABILITY OVER THE NEXT FEW
HOURS COMBINED WITH THE DEEP LOW LEVEL MOISTURE PRESENT...WEAK
FORCING ALOFT AND THE PRESENCE OF THE BOUNDARY ACROSS THE
REGION...REALLY HARD TO ARGUE WITH THIS SCENARIO AT THIS POINT.
BUMPED UP POPS TO BEGIN NORTHWEST OF INDY NOW...THEN INCREASE TO
30-50 POPS OVER ENTIRE FORECAST AREA FOR THE AFTERNOON. MENTIONING
ONLY ISOLATED THUNDER THROUGH MIDDAY AS MESOANALYSIS SHOWS LITTLE
INSTABILITY PRESENT RIGHT NOW. EXPECT A BETTER CHANCE FOR THUNDER
THIS AFTERNOON AS INSTABILITY INCREASES WITH DIURNAL HEATING.
WHILE THERE ARE BREAKS IN THE CLOUD COVER THIS MORNING...
ESPECIALLY OVER SOUTHERN COUNTIES...HAVE INCREASED CLOUD COVERAGE
FOR THE AFTERNOON AS CU LIKELY TO FILL IN AS CONVECTIVE TEMPS ARE
MET. ADDITIONALLY...CLOUD DEBRIS FROM WEAKENING MCS OVER THE
OZARKS POISED TO EXPAND INTO THE REGION THIS AFTERNOON. WITH THE
INCREASE IN CLOUDS...DROPPED HIGH TEMPS A COUPLE DEGREES AS WELL.
ZONE AND GRID UPDATES OUT SHORTLY.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 210 AM EDT THU AUG 8 2013
LITTLE CHANGE APPEARS IN THE OVERALL PATTERN THROUGH FRIDAY
AFTERNOON. GFS AND NAM CONTINUE TO SUGGEST WEAK...POORLY ORGANIZED
SHORT WAVES PUSHING THROUGH THE FLOW ALOFT. MEANWHILE THE FRONTAL
BOUNDARY LINGERS NEAR THE OHIO VALLEY. 310K GFS ISENTROPIC SURFACE
FAILS TO SHOW MUCH IN THE WAY OF LIFT...BUT DOES MANAGE TO
ILLUSTRATE THE VERY MOIST AIR MASS ACROSS THE AREA SHOWING
SPECIFIC HUMIDITIES IN EXCESS OF 4 G/KG ON FRIDAY. FORECAST
SOUNDINGS THROUGH FRIDAY SHOW LESS FAVORABLE LAPSE RATES WITH
LESS CAPE THAN TODAY. HOWEVER WITH THE MOIST FLOW ALOFT...MOIST
AIR IN PLACE AT THE SURFACE AND UNCERTAINTY REMAINING WITH ANY
EMBEDDED SHORT WAVES WILL CONTINUE TO KEEP LOW CHC POPS TONIGHT
AND AGAIN ON FRIDAY. WILL TREND LOWS WARMER THAN MAVMOS AND STICK
CLOSE ON HIGHS FOR FRIDAY.
ON FRIDAY NIGHT THE GFS AND NAM BOTH SUGGEST A STRONG SHORT WAVE
ALOFT SWEEPING THROUGH THE FLOW. TIME HEIGHT SECTIONS BEGIN TO
SHOW MORE VV WHILE THE NAM SOUNDINGS SHOW DEEP SATURATION. THE GFS
IS MUCH LESS AGGRESSIVE WITH SATURATION...BUT STILL DOES SHOW THE
MAIN WAVE ALOFT. MEANWHILE GFS 310K ISENTROPIC SURFACE SHOWS
MINIMAL LIFT...BUT A VERY MOIST AIR MASS IN PLACE WITH SPECIFIC
HUMIDITIES OVER 5 G/KG AGAIN. IN THE LOWER LEVELS...BEST
CONVERGENCE REMAINS NEAR THE FRONT...LINGERING NEAR THE OHIO
RIVER. THUS WILL USE A BLEND OF THE LOW GFS POPS AND THE HIGHER
NAM POPS FOR FRIDAY NIGHT.
A MUCH DIFFERENT AIR MASS ARRIVES ON SATURDAY AND SATURDAY NIGHT
AS HIGH PRESSURE BUILDS ACROSS THE AREA FROM CANADA. FORECAST
SOUNDINGS AGREE AS THE COLUMN DRIES OUT DRAMATICALLY AMID
SUBSIDENCE. CONVECTIVE TEMPERATURES LOOK QUITE REACHABLE WITH A
MID LEVEL CAP IN PLACE...THUS EXPECTED SOME AFTERNOON CU ON
SATURDAY AND MOSTLY CLEAR SKIES THAT NIGHT. GIVEN THE FORECAST
SOUNDINGS WILL TREND HIGHS ON SATURDAY COOLER THAN MAVMOS AND
STICK CLOSE ON LOWS.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
ISSUED AT 230 AM EDT THU AUG 8 2013
LONG TERM PERIOD CONTINUES TO BE CHARACTERIZED BY ZONAL TO
MODERATELY CYCLONIC FLOW...SUGGESTING TEMPERATURES NEAR TO A FEW
DEGREES BELOW NORMAL. INITIALIZATION HANDLES THIS WELL AND FEW
CHANGES REQUIRED.
DID CONFINE ONLY SLIGHT CHANCE POPS TO MONDAY AS GFS SUGGESTS A
WEAK FRONTAL PASSAGE WHICH COULD POP A SHOWER OR ISOLATED STORM.
BEYOND MONDAY...IN OTHER PERIODS POPS ARE NOT MERITED...AND WERE
REMOVED.
&&
.AVIATION /DISCUSSION FOR THE 08/12Z TAFS/...
ISSUED AT 705 AM EDT THU AUG 8 2013
SO FAR THIS MORNING...IND HAS MADE IT TO IFR BUT OTHER SITES HAVE
ONLY FLIRTED WITH MVFR. ANY RESTRICTIONS SHOULD END BY MID
MORNING...WITH BROKEN VFR STRATOCU REPLACING THEM.
CANNOT ENTIRELY RULE OUT A FEW SHOWERS OR STORMS TODAY...BUT WITH
MAJOR UNCERTAINTY IN TIMING AND PLACEMENT...CANNOT MENTION RIGHT NOW.
LATE IN THE PERIOD...GUIDANCE WANTS TO REDEVELOP
RESTRICTIONS...QUITE LOW IN SOME SPOTS. LAMP WAS SIGNIFICANTLY
OVERAGGRESSIVE TONIGHT...SO WILL LEAVE ANY MENTION OF RESTRICTIONS
OUT FOR NOW EXCEPT AT BMG...WHICH IS ONE OF THE FOGGIER SITES AND
WILL BE A BIT CLOSER TO THE BOUNDARY AND IN A SLIGHTLY RICHER
AIRMASS.
WINDS WILL BE BELOW 10KT THROUGHOUT THE PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...RYAN
SHORT TERM...PUMA
LONG TERM....NIELD
AVIATION...NIELD
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS WICHITA KS
108 PM CDT THU AUG 8 2013
.UPDATE...
ISSUED AT 102 PM CDT THU AUG 8 2013
MCV OVER EASTERN KS WAS NOT WELL HANDLED BY OVERNIGHT GUIDANCE AND
ONLY MARGINALLY WELL BY 1200 UTC RUNS. RADAR/SATELLITE TRENDS SHOW
PRECIPITATION ON THE WANE. BEST CHANCES LIKELY WILL BE IN SOUTHEAST
KS WHERE DEEPER MOISTURE/BETTER INSOLATION AND INSTABILITY MAY BE
SUFFICIENT TO BREAK CAP LATE THIS AFTERNOON/EVENING. ANTICIPATING
PRECIPITATION TO WANE THIS EVENING AND MUCH OF THE NIGHT...BUT
SIMILAR TO THIS MORNING...BELIEVE PRECIPITATION WILL DEVELOP AND
MOVE INTO SOUTH CENTRAL/SOUTHEAST KS JUST PRIOR TO DAYBREAK. EARLY
LOOK APPEARS TO SUGGEST THAT PRECIPITATION MAY NOT BE AS HEAVY AS
PREVIOUS DAYS. TEMPERATURES THIS AFTERNOON WILL LIKELY REBOUND
WITH SOME BREAKS IN CLOUDS IN SOUTHEAST KS. -HOWERTON
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 328 AM CDT THU AUG 8 2013
TODAY & TONIGHT:
AS ALL OBVIOUSLY KNOW...FLOODING TO CONTINUE BEINGING THE HIGHLIGHT OF
FOR PERIODS AS FLOOD WATCH REMAINS IN EFFECT TIL 7 AM FRIDAY.
DURING THE NIGHT A POORLY-DEFINED STATIONARY FRONT WAS DRAPED IN AN E-W
MANNER GENERALLY THROUGH CNTRL OK WITH A WEAK 700-MB TROF SITUATED FROM
THE UT/CO BORDER TO ~CA/AZ BORDER. WITH THE TROF SLOWLY EVOLVING INTO A
WEAK LOW AS IT VENTURES E TO WRN KS RICH & DEEP MOISTURE WILL CONTINUE
TO SPREAD NE ACROSS KS. WITH THE MID-LVL "KICKER" LACKING THE SFC-850MB
FRONTS WILL MOVE VERY LITTLE...IF AT ALL...THEREBY PROMOTING BROAD ECHO
TRAINING OVER KICT COUNTRY WHICH IN TURN WOULD EXACERBATE THE FLOODING
SITUATION ACROSS THE CWA. ONLY CHANGES TO INHERITED FORECAST WERE TO
SHIFT THE POP GRADIENT TO GENERALLY A N/S ORIENTATION TO BETTER ALIGN
WITH THE BROAD LWR-MID DECK MOISTURE CHANNEL. ASSIGNED 80-100% TO CNTRL
& SC KS THIS MORNING WITH HIGHEST POPS & ASSOCIATED TSRA SHIFTED E OVER
SE KS THIS AFTERNOON AS HRRR DEPICTS. PW`S REMAIN IN 175-200% RANGE SO
CONTINUED TO HIT QPFS HARD.
FRI & FRI NIGHT:
A FAIRLY BROAD UPR-DECK RIDGE IS FORECAST MOVE SLOWLY MOVG E TOWARD THE
CNTRL ROCKIES...THE WEAK MID-LVL LOW WILL GET FORCED E TOWARD...THEN
ACROSS...ERN KS. THIS WOULD THEREFORE SHIFT BULK OF +TSRA E ACROSS THE
KS/MO BORDER ON FRI WITH -TSRA CONFINED FROM GENERALLY THE FLINT HILLS
E FRI NGT. AS SUCH WILL CONTINUE TO SCHEDULE THE FLOOD WATCH TO END AT
7AM FRI.
SAT & SAT NGT:
MOST AREAS WILL EXPERIENCE AN INTERMISSION FROM TSRA. A FEW TSRA SHOULD
VENTURE TOWARD THE WRN CORRIDOR SAT NGT AS WEAK LWR-DECK TROFFING
BEGINS ALONG THE FRONT RANGE.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 328 AM CDT THU AUG 8 2013
ALL AREAS TO BE UNDER A WEAK NW FLOW REGIME FOR MOST OF THESE PERIODS.
A WEAK COLD FRONT WILL VENTURE SE TOWARD & PERHAPS ACROSS KICGT COUNTRY
EARLY NEXT WEEK WHICH WOULD INCREASE TSRA CHANCES FOR MUCH OF THESE
PERIODS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 102 PM CDT THU AUG 8 2013
ANTICIPATE VFR CONDITIONS THIS AFTERNOON...ALTHOUGH A FEW SITES MAY
BRIEFLY HAVE MVFR CEILINGS AT THE ONSET. ISOLATED/SCATTERED
THUNDERSTORMS POSSIBLE AT KCNU/SE KS LATER THIS AFTERNOON/EVENING
DRIVEN BY AFTERNOON HEATING AND DEEP LOW LEVEL MOISTURE. BETTER
CHANCES OF PRECIPTATION WILL OCCUR CLOSER TO DAYBREAK AT
KHUT/KICT/KCNU AS NEXT IN SERIES OF UPPER SHORTWAVES MOVE THROUGH
THE AREA. -HOWERTON
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 68 79 65 83 / 50 40 10 10
HUTCHINSON 65 76 63 82 / 40 40 10 10
NEWTON 66 76 63 81 / 40 50 10 10
ELDORADO 67 79 64 82 / 50 50 20 10
WINFIELD-KWLD 70 82 66 84 / 60 30 10 10
RUSSELL 63 76 62 82 / 20 40 10 10
GREAT BEND 63 75 61 81 / 30 40 10 10
SALINA 65 77 63 83 / 30 50 10 10
MCPHERSON 65 76 63 82 / 30 50 10 10
COFFEYVILLE 71 86 68 84 / 80 40 20 10
CHANUTE 69 81 66 82 / 70 60 20 10
IOLA 68 80 66 81 / 60 70 20 10
PARSONS-KPPF 70 84 67 83 / 80 50 20 10
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH THROUGH FRIDAY MORNING FOR KSZ032-033-047>053-
067>072-082-083-091>096-098>100.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1159 AM MDT THU AUG 8 2013
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 446 AM MDT THU AUG 8 2013
FORECAST CONCERNS WILL BE THREAT OF HEAVY RAINFALL AND CHANCES OF
PRECIPITATION. SATELLITE SHOWING LITTLE CHANGE AS A COMPLEX AND
AMPLIFIED PATTERN FROM THE CENTRAL PACIFIC INTO NORTH AMERICA
REMAINS IN PLACE. COMPLEX AND SLOW MOVING UPPER HAS MOVED INTO
COLORADO AND NEW MEXICO. SEVERAL SHORTWAVE TROUGHS ROTATING AROUND
THIS MAIN SYSTEM. AIR MASS REMAINS MOIST THROUGH A DEEP LAYER.
PERSISTENT FRONTAL BOUNDARY REMAINS DRAPED TO OUR SOUTH AND WEST.
AT JET LEVEL...THE CANADIAN AND THE UKMET INITIALIZED BEST ON THE
JET THAT IS OVER/NEAR OUR AREA. AT MID LEVELS...SATELLITE AND UPPER
AIR ANALYSIS SHOW THAT THE ECMWF/CANADIAN FOLLOWED BY THE GFS ARE
HANDLING CURRENT SYSTEM THE BEST. SREF AND RUC WERE DOING BEST AT
THE SURFACE.
COMPLICATED AND DIFFICULT PRECIPITATION FORECAST MADE MORE DIFFICULT
BY THE FACT THAT MOST IF NOT ALL THE MODEL OUTPUT HAS CURRENT
PRECIPITATION SHIELD TOO FAR SOUTH AND IS BASICALLY IGNORING IT.
TODAY/TONIGHT...WEAK RIGHT REAR QUADRANT OF THE UPPER JET REMAINS
OVER THE AREA FOR MOST OF THE DAY. MODELS ARE IN A LITTLE MORE
DISAGREEMENT ON HOW FAST TO MOVE THIS SEGMENT EAST. ALTHOUGH THE
GENERAL TREND IS TO HAVE THIS SLOWER/FURTHER WEST THAN THE PREVIOUS
TWO DAYS. THE SLOWEST OF THE MODELS DO NOT TAKE THIS RIGHT REAR
QUADRANT TO THE EAST OF THE FORECAST AREA UNTIL BETWEEN 06Z AND 12Z.
BASED ON CURRENT SATELLITE...LATEST ECMWF IS CATCHING THE POSITION
AND COMPLEXITY OF THE UPPER TROUGH THE BEST. CONSIDERING THE
POSITION OF THE 700 MB LOW CIRCULATION...MODELS INDICATING WARM
ADVECTION/UPGLIDE IN ADVANCE OF IT...PLUS STRONG UPPER DIVERGENCE
INDICATED THE EASTERN PORTION OF THE AREA...BELIEVE THE CURRENT
PRECIPITATION WILL CONTINUE TO MOVE AND DEVELOP AND MAINLY AFFECT
THE EASTERN THIRD TO HALF OF THE FORECAST AREA.
THIS LOOKS TO BE THE BEST AREA FOR MODERATE TO HEAVY RAINFALL TO
CONTINUE THROUGH AT LEAST THIS AFTERNOON. GREELEY AND WALLACE
COUNTIES APPEAR TO BE ON THE EDGE THIS AREA AT THIS TIME. HOWEVER...
BOTH OF THOSE COUNTIES...ESPECIALLY WALLACE...GOT AT LEAST 2 TO 5
INCHES OF RAINFALL LAST. SO BELIEVE CHEYENNE COUNTY COLORADO DID
NOT RECEIVE A LOT OF HEAVY RAINFALL AND DO NOT EXPECT IT TODAY...
REMOVED THEM FROM THE FLASH FLOOD WATCH. KEPT THE REMAINDER IN THE
WATCH AND EXTENDED IT THROUGH THE AFTERNOON HOURS DUE TO THE SLOW
PROGRESSION OF THE SYSTEM ACROSS THE AREA.
QUESTION THEN BECOMES HOW FAR WEST TO BRING THE PRECIPITATION. THE
ECMWF IS SHOWING WRAP AROUND PRECIPITATION AND THE HRRR INDICATING
THE SAME IDEA. VERY INTERESTING OCCURRENCE FOR THIS TIME OF YEAR.
CURRENT RADAR TRENDS WOULD INDICATE THIS IS TAKING PLACE. SO KEPT
HIGHER POPS FURTHER WEST AS A RESULT. OVERALL...IF THE ECMWF IS RIGHT
AND IT IS SUPPORTED BY THE GEFS...THIS RAINFALL...EVEN AFTER THE
INTENSITY LETS UP...WILL BE SLOW TO END AND WILL PROBABLY NOT DO SO
UNTIL LATE TONIGHT. DID NOT INSERT AT THIS TIME BUT FOG WILL BE
POSSIBLE IF RAIN QUITS SOONER AND CLEARING CAN OCCUR.
LOWERED MAXES TODAY DUE TO CONTINUED PRECIPITATION AND THICK CLOUD
COVER.
FRIDAY/FRIDAY NIGHT...INTEREST PATTERN CONTINUES. THE ECMWF SHOWING
IT MORE BUT ALSO INDICATED BY THE OTHER MODELS AND GEFS OUTPUT...
MID LEVEL TROUGH REMAINS NEAR TO OVER THE AREA WITH WHAT LOOKS TO BE
A DECENT AMOUNT OF MOISTURE LEFT. ALSO A LEFT FRONT QUADRANT OF A
SOUTHERN JET BECOMES ESTABLISHED OVER THE AREA...ESPECIALLY THE
SOUTHEAST HALF...BY THE MIDDLE OF THE DAY. THIS CONTINUES TO AFFECT
THE AREA...ESPECIALLY THE SOUTHERN HALF...THROUGH THE ENTIRE NIGHT.
SO INSERTED POPS WITH THE HIGHEST IN THE SOUTHEAST PORTION. WITH
PERSISTENT CLOUD COVER AND UNFAVORABLE SURFACE WINDS...TRENDED
MAXES DOWN A LITTLE. IF ENOUGH CLEARING CAN OCCUR AND WITH THE MOIST
AIR MASS AND WET GROUND IN PLACE...WOULD NOT BE SURPRISED TO SEE FOG
DEVELOP.
SATURDAY/SATURDAY NIGHT...SOME DIFFERENCE IN THE JET STRUCTURE
THROUGH THE DAY. AS A RESULT IT LOOKS LIKE SOME OR MOST OF THE AREA
COULD GET LIFT FROM THE JET IN THE AREA. MID LEVEL RIDGE MOVES A
LITTLE EAST WITH A SHORTWAVE TROUGH APPROACHING FROM THE WEST IN THE
AFTERNOON. LEE TROUGH STRENGTHENS WITH SOUTHERLY WINDS INCREASING.
POSSIBILITY OF SOME SURFACE CONVERGENCE IN THE FAR WEST. SO PUT IN
A SLIGHT CHANCE IN THE FAR WEST.
ABOVE MENTIONED SHORTWAVE TROUGH AND INCREASING MID LEVEL WARM AIR
ADVECTION PATTERN ALONG WITH INCREASING JET LIFT COULD CAUSE SOME
ISOLATED THUNDERSTORMS OVER THE MOST OF THE AREA. SO PULLED THE
SLIGHT CHANCE FURTHER EAST DURING THE NIGHT.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 446 AM MDT THU AUG 8 2013
UPPER PATTERN THIS PERIOD WILL SLOWLY EVOLVE FROM AN ELONGATED
EAST-WEST UPPER HIGH OVER THE SOUTHERN U.S. TO A HIGH CENTERED OVER
NEW MEXICO AND A SUBSEQUENT GRADUAL BUILDING OF HEIGHTS OVER THE
CENTRAL ROCKIES. MEANWHILE...UPPER LOWS WILL REMAIN ANCHORED OFF
THE PAC NW COAST AND NEAR JAMES BAY...RESULTING IN WEAK TO MODERATE
NORTHWEST FLOW ALOFT ACROSS THE NORTHERN AND CENTRAL PLAINS. A FEW
WEAK SHORT WAVE TROUGHS WILL LIFT OUT OF THE WEST COAST TROUGH AND
RIDE OVER THE TOP OF THE ROCKIES RIDGE...PROVIDING A FEW
OPPORTUNITIES FOR PRECIP NEXT WEEK AS THEY EMERGE ONTO THE PLAINS.
CURRENT GUIDANCE SUGGESTS THE MON-TUE TIME FRAME WILL PROVIDE
SOMEWHAT BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS...AND THIS IS
INDICATED WITH 30-40 POPS COMPARED TO 20 POPS ON REMAINING DAYS.
NORTHWEST FLOW ALOFT WILL BRING A SURFACE CANADIAN AIRMASS DOWN NEXT
WEEK SUGGESTING HIGH TEMPERATURES WILL REMAIN SEASONAL IN THE 80S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1159 AM MDT THU AUG 8 2013
SHOWERS AND MVFR CEILINGS SHOULD SLOWLY DIMINISH ACROSS THE TRI-
STATE AREA OVER THE NEXT COUPLE OF HOURS WITH VFR CONDITIONS
TAKING OVER THIS AFTERNOON. SKIES ARE EXPECTED TO GRADUALLY
CLEAR...ESPECIALLY AT KMCK...ALLOWING FOR GOOD RADIATIONAL COOLING
TONIGHT. WITH RECENT RAINFALL AND LIGHT WINDS...FOG AND STRATUS IS
EXPECTED TO DEVELOP WITH IFR TO LIFR CONDITIONS FORECAST. IF SKIES
DO NOT CLEAR OUT TONIGHT...CONDITIONS MAY NOT BE AS BAD DURING THE
OVERNIGHT HOURS. MOST GUIDANCE IS NOT SUGGESTING FOG...HOWEVER IT
SEEMS MODELS ARE HAVING A TOUGH TIME CAPTURING PRESENT WEATHER
CONDITIONS. WINDS ARE EXPECTED TO REMAIN LIGHT THROUGHOUT THE TAF
PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...FLASH FLOOD WATCH UNTIL 6 PM MDT /7 PM CDT/ THIS EVENING FOR
KSZ027>029-041-042.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...DLF
AVIATION...RRH
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1205 PM CDT Thu Aug 8 2013
...Updated for the aviation discussion...
.SYNOPSIS...
ISSUED AT 1010 PM CDT WED AUG 7 2013
The 08.00Z 250 hPa showed 50 KT flow extending from KDDC increasing
to around 100 KT at KAPX. @ 500 hPa, a 577-580 decameter cyclone was
spinning off northwest California. Downstream, an open wave was moving
across the central Rockies. A huge 550 decameter cyclone was noted across
west central Ontario. @ 700 hPa, easterly upslope flow was observed
at KDDC. This upslope flow also continued at 850 hPa and down to the
sfc. The precipitable water for KDDC was 1.41" (above the 75th percentile
for a Gaussian distribution). At the sfc, a stationary front was located
across the KS/OK state border. KDDC WSR-88D was busy indicating an
MCS to the west.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 254 AM CDT THU AUG 8 2013
...Pretty busy shift this morning. Most of the attention was paid to
overnight convection and then some to this afternoon...
This morning:
A fairly significant rain event occurred through the overnight period.
Rainfall reports have been pretty sparse given the fact that it is O`Dark
Thirty. We should get more reports by dawn. A few reports have trickled
in with 3.00" in Hugoton, 1.50" by Richfield, and a few flash flooding
reports. Here at the KDDC airport as of 07:24Z, we have had a measly
half of an inch. Southern Ford county and other areas probably saw 2"
to 4" via estimation from radar. Anyway, given the initial event, canceled
the Flood Watch and issued a Flash Flood Watch instead. So, why all
the precip? Well, an upper level wave, 850 hPa theta-e advection, pwats
around the 75th percentile, sfc-700 hPa upslope flow, and isentropic
lift was the impetus for MCS formation. For the rest of the early morning,
will taper precipitation probability percentage points west to east
via radar trends and HRRR guidance. FWIW, the 00Z NAM performed poorly
for the event.
Will carry the FF.A (Flash Flood Watch) until 18Z.
Today/tonight:
We should see some break in the precipitation from the morning activity
to possible additional activity later this afternoon as temporary subsidence
builds in the wake of the departing MCS. Forecast skew-t/log-p`s show
pwats still in the 1.50-1.70" range this afternoon. A moist upslope
flow will also continue from the sfc up through 800 hPa. The main synoptic
wave mentioned in the synopsis will have translated over western Kansas by
afternoon, and this will provide some upper level support for additional
lift. The atmosphere will become unstable again with 1000-2000 J/kg
of SBCAPE. Low to mid level lapse rates are fairly moist adiabatic,
so the CAPE profile is fairly skinny. Bulk shear vectors are SW/40 KT.
All and all, tomorrow does not look that impressive for severe weather
(supercells etc). What does look more promising is another MCS. There
is significant questions in regarding convective initiation/placement.
The ECMWF and both cores of the WRF look reasonable. The atmosphere
could be "worked over" from the morning convection, so a lack of additional
activity is also possible. Anywho, will carry chance precipitation probabilities
this afternoon and ramp them up to likely region wide by tonight. Maximums
will be in the 70sF and minimums in the 60sF.
.LONG TERM...(Friday through Wednesday)
ISSUED AT 353 AM CDT THU AUG 8 2013
A shortwave trough will move across the central plains reaching
the lower Missouri River Valley by late Friday with shortwave
ridging moving into the western plains. This will provide a break
in precipitation chances from late Friday into Saturday night with
surface ridging across Kansas. Low level moisture will still be
around, however, given all the saturated ground providing ample
evapotranspiration...so dewpoint temperatures will remain int he
60s for the most part despite there being some mid level
subsidence. Some subtropical jet energy will begin to move into
the desert Southwest region impinging on the southern Rockies by
Sunday night into early next week...and this is when precipitation
chances will once again be on the increase. As far as the grids
go...no changes were made to the forecast and the latest all-blend
guidance was used for the Sunday-Thursday time frame.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 1154 AM CDT THU AUG 8 2013
For much of the forecast, expect just scatttered clouds in the 020
range this afternoon, with a scattered to broken deck at 120-150.
As the abundant low level moisture hangs around tonight, and light
easterly upslope winds continue, low stratus in the ovc007 ifr
range will form after 04Z tonight.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 75 63 78 61 / 80 80 20 10
GCK 74 61 77 57 / 70 70 20 10
EHA 77 62 80 60 / 60 60 10 10
LBL 79 63 80 61 / 60 60 20 10
HYS 74 62 76 61 / 90 80 30 10
P28 80 67 81 65 / 80 80 30 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH until 1 PM CDT /Noon MDT/ this afternoon FOR
KSZ030-031-043>046-061>066-074>081-084>090.
&&
$$
SYNOPSIS...SUGDEN
SHORT TERM...SUGDEN
LONG TERM...UMSCHEID
AVIATION...BURKE
AREA FORECAST DISCUSSION
NWS WICHITA KS
708 AM CDT THU AUG 8 2013
UPDATED 12Z AVIATION SECTION.
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 328 AM CDT THU AUG 8 2013
TODAY & TONIGHT:
AS ALL OBVIOUSLY KNOW...FLOODING TO CONTINUE BEINGING THE HIGHLIGHT OF
FOR PERIODS AS FLOOD WATCH REMAINS IN EFFECT TIL 7 AM FRIDAY.
DURING THE NIGHT A POORLY-DEFINED STATIONARY FRONT WAS DRAPED IN AN E-W
MANNER GENERALLY THROUGH CNTRL OK WITH A WEAK 700-MB TROF SITUATED FROM
THE UT/CO BORDER TO ~CA/AZ BORDER. WITH THE TROF SLOWLY EVOLVING INTO A
WEAK LOW AS IT VENTURES E TO WRN KS RICH & DEEP MOISTURE WILL CONTINUE
TO SPREAD NE ACROSS KS. WITH THE MID-LVL "KICKER" LACKING THE SFC-850MB
FRONTS WILL MOVE VERY LITTLE...IF AT ALL...THEREBY PROMOTING BROAD ECHO
TRAINING OVER KICT COUNTRY WHICH IN TURN WOULD EXACERBATE THE FLOODING
SITUATION ACROSS THE CWA. ONLY CHANGES TO INHERITED FORECAST WERE TO
SHIFT THE POP GRADIENT TO GENERALLY A N/S ORIENTATION TO BETTER ALIGN
WITH THE BROAD LWR-MID DECK MOISTURE CHANNEL. ASSIGNED 80-100% TO CNTRL
& SC KS THIS MORNING WITH HIGHEST POPS & ASSOCIATED TSRA SHIFTED E OVER
SE KS THIS AFTERNOON AS HRRR DEPICTS. PW`S REMAIN IN 175-200% RANGE SO
CONTINUED TO HIT QPFS HARD.
FRI & FRI NIGHT:
A FAIRLY BROAD UPR-DECK RIDGE IS FORECAST MOVE SLOWLY MOVG E TOWARD THE
CNTRL ROCKIES...THE WEAK MID-LVL LOW WILL GET FORCED E TOWARD...THEN
ACROSS...ERN KS. THIS WOULD THEREFORE SHIFT BULK OF +TSRA E ACROSS THE
KS/MO BORDER ON FRI WITH -TSRA CONFINED FROM GENERALLY THE FLINT HILLS
E FRI NGT. AS SUCH WILL CONTINUE TO SCHEDULE THE FLOOD WATCH TO END AT
7AM FRI.
SAT & SAT NGT:
MOST AREAS WILL EXPERIENCE AN INTERMISSION FROM TSRA. A FEW TSRA SHOULD
VENTURE TOWARD THE WRN CORRIDOR SAT NGT AS WEAK LWR-DECK TROFFING
BEGINS ALONG THE FRONT RANGE.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 328 AM CDT THU AUG 8 2013
ALL AREAS TO BE UNDER A WEAK NW FLOW REGIME FOR MOST OF THESE PERIODS.
A WEAK COLD FRONT WILL VENTURE SE TOWARD & PERHAPS ACROSS KICGT COUNTRY
EARLY NEXT WEEK WHICH WOULD INCREASE TSRA CHANCES FOR MUCH OF THESE
PERIODS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 706 AM CDT THU AUG 8 2013
LARGE MESOSCALE CONVECTIVE SYSTEM (MCS)CONTINUES TO MAKE SLOW
PROGRESS ACROSS THE ERN HALF OF KS AT THIS TIME. THIS WILL LEAD TO
MVFR VSBYS WITH SHRA/VCTS FOR MOST TAF SITES UNTIL 15-16Z. AFTER
THIS MCS MOVES EAST...WILL SEE SOME MID LEVEL CLOUDS AT 4K FEET HAND
AROUND FOR THE AFTERNOON HOURS.
SHOWERS/STORMS COULD REDEVELOP AND BECOME FAIRLY WIDESPREAD LATE
THIS EVENING INTO THE OVERNIGHT...ESPECIALLY ACROSS SRN KS. COULD
SEE SOME VSBY/CIG REDUCTIONS INTO AT LEAST THE MVFR RANGE AT TIMES
OVERNIGHT.
KETCHAM
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 80 68 79 65 / 100 90 40 10
HUTCHINSON 78 65 76 63 / 100 90 40 10
NEWTON 78 66 76 63 / 100 90 50 10
ELDORADO 79 67 79 64 / 100 90 50 20
WINFIELD-KWLD 82 70 82 66 / 100 70 30 10
RUSSELL 77 63 76 62 / 100 70 40 10
GREAT BEND 77 63 75 61 / 100 80 40 10
SALINA 78 65 77 63 / 100 80 50 10
MCPHERSON 78 65 76 63 / 100 80 50 10
COFFEYVILLE 85 71 86 68 / 80 80 40 20
CHANUTE 81 69 81 66 / 80 80 60 20
IOLA 80 68 80 66 / 80 80 70 20
PARSONS-KPPF 83 70 84 67 / 80 80 50 20
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH THROUGH FRIDAY MORNING FOR KSZ032-033-047>053-
067>072-082-083-091>096-098>100.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
554 AM MDT THU AUG 8 2013
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 446 AM MDT THU AUG 8 2013
FORECAST CONCERNS WILL BE THREAT OF HEAVY RAINFALL AND CHANCES OF
PRECIPITATION. SATELLITE SHOWING LITTLE CHANGE AS A COMPLEX AND
AMPLIFIED PATTERN FROM THE CENTRAL PACIFIC INTO NORTH AMERICA
REMAINS IN PLACE. COMPLEX AND SLOW MOVING UPPER HAS MOVED INTO
COLORADO AND NEW MEXICO. SEVERAL SHORTWAVE TROUGHS ROTATING AROUND
THIS MAIN SYSTEM. AIR MASS REMAINS MOIST THROUGH A DEEP LAYER.
PERSISTENT FRONTAL BOUNDARY REMAINS DRAPED TO OUR SOUTH AND WEST.
AT JET LEVEL...THE CANADIAN AND THE UKMET INITIALIZED BEST ON THE
JET THAT IS OVER/NEAR OUR AREA. AT MID LEVELS...SATELLITE AND UPPER
AIR ANALYSIS SHOW THAT THE ECMWF/CANADIAN FOLLOWED BY THE GFS ARE
HANDLING CURRENT SYSTEM THE BEST. SREF AND RUC WERE DOING BEST AT
THE SURFACE.
COMPLICATED AND DIFFICULT PRECIPITATION FORECAST MADE MORE DIFFICULT
BY THE FACT THAT MOST IF NOT ALL THE MODEL OUTPUT HAS CURRENT
PRECIPITATION SHIELD TOO FAR SOUTH AND IS BASICALLY IGNORING IT.
TODAY/TONIGHT...WEAK RIGHT REAR QUADRANT OF THE UPPER JET REMAINS
OVER THE AREA FOR MOST OF THE DAY. MODELS ARE IN A LITTLE MORE
DISAGREEMENT ON HOW FAST TO MOVE THIS SEGMENT EAST. ALTHOUGH THE
GENERAL TREND IS TO HAVE THIS SLOWER/FURTHER WEST THAN THE PREVIOUS
TWO DAYS. THE SLOWEST OF THE MODELS DO NOT TAKE THIS RIGHT REAR
QUADRANT TO THE EAST OF THE FORECAST AREA UNTIL BETWEEN 06Z AND 12Z.
BASED ON CURRENT SATELLITE...LATEST ECMWF IS CATCHING THE POSITION
AND COMPLEXITY OF THE UPPER TROUGH THE BEST. CONSIDERING THE
POSITION OF THE 700 MB LOW CIRCULATION...MODELS INDICATING WARM
ADVECTION/UPGLIDE IN ADVANCE OF IT...PLUS STRONG UPPER DIVERGENCE
INDICATED THE EASTERN PORTION OF THE AREA...BELIEVE THE CURRENT
PRECIPITATION WILL CONTINUE TO MOVE AND DEVELOP AND MAINLY AFFECT
THE EASTERN THIRD TO HALF OF THE FORECAST AREA.
THIS LOOKS TO BE THE BEST AREA FOR MODERATE TO HEAVY RAINFALL TO
CONTINUE THROUGH AT LEAST THIS AFTERNOON. GREELEY AND WALLACE
COUNTIES APPEAR TO BE ON THE EDGE THIS AREA AT THIS TIME. HOWEVER...
BOTH OF THOSE COUNTIES...ESPECIALLY WALLACE...GOT AT LEAST 2 TO 5
INCHES OF RAINFALL LAST. SO BELIEVE CHEYENNE COUNTY COLORADO DID
NOT RECEIVE A LOT OF HEAVY RAINFALL AND DO NOT EXPECT IT TODAY...
REMOVED THEM FROM THE FLASH FLOOD WATCH. KEPT THE REMAINDER IN THE
WATCH AND EXTENDED IT THROUGH THE AFTERNOON HOURS DUE TO THE SLOW
PROGRESSION OF THE SYSTEM ACROSS THE AREA.
QUESTION THEN BECOMES HOW FAR WEST TO BRING THE PRECIPITATION. THE
ECMWF IS SHOWING WRAP AROUND PRECIPITATION AND THE HRRR INDICATING
THE SAME IDEA. VERY INTERESTING OCCURRENCE FOR THIS TIME OF YEAR.
CURRENT RADAR TRENDS WOULD INDICATE THIS IS TAKING PLACE. SO KEPT
HIGHER POPS FURTHER WEST AS A RESULT. OVERALL...IF THE ECMWF IS RIGHT
AND IT IS SUPPORTED BY THE GEFS...THIS RAINFALL...EVEN AFTER THE
INTENSITY LETS UP...WILL BE SLOW TO END AND WILL PROBABLY NOT DO SO
UNTIL LATE TONIGHT. DID NOT INSERT AT THIS TIME BUT FOG WILL BE
POSSIBLE IF RAIN QUITS SOONER AND CLEARING CAN OCCUR.
LOWERED MAXES TODAY DUE TO CONTINUED PRECIPITATION AND THICK CLOUD
COVER.
FRIDAY/FRIDAY NIGHT...INTEREST PATTERN CONTINUES. THE ECMWF SHOWING
IT MORE BUT ALSO INDICATED BY THE OTHER MODELS AND GEFS OUTPUT...
MID LEVEL TROUGH REMAINS NEAR TO OVER THE AREA WITH WHAT LOOKS TO BE
A DECENT AMOUNT OF MOISTURE LEFT. ALSO A LEFT FRONT QUADRANT OF A
SOUTHERN JET BECOMES ESTABLISHED OVER THE AREA...ESPECIALLY THE
SOUTHEAST HALF...BY THE MIDDLE OF THE DAY. THIS CONTINUES TO AFFECT
THE AREA...ESPECIALLY THE SOUTHERN HALF...THROUGH THE ENTIRE NIGHT.
SO INSERTED POPS WITH THE HIGHEST IN THE SOUTHEAST PORTION. WITH
PERSISTENT CLOUD COVER AND UNFAVORABLE SURFACE WINDS...TRENDED
MAXES DOWN A LITTLE. IF ENOUGH CLEARING CAN OCCUR AND WITH THE MOIST
AIR MASS AND WET GROUND IN PLACE...WOULD NOT BE SURPRISED TO SEE FOG
DEVELOP.
SATURDAY/SATURDAY NIGHT...SOME DIFFERENCE IN THE JET STRUCTURE
THROUGH THE DAY. AS A RESULT IT LOOKS LIKE SOME OR MOST OF THE AREA
COULD GET LIFT FROM THE JET IN THE AREA. MID LEVEL RIDGE MOVES A
LITTLE EAST WITH A SHORTWAVE TROUGH APPROACHING FROM THE WEST IN THE
AFTERNOON. LEE TROUGH STRENGTHENS WITH SOUTHERLY WINDS INCREASING.
POSSIBILITY OF SOME SURFACE CONVERGENCE IN THE FAR WEST. SO PUT IN
A SLIGHT CHANCE IN THE FAR WEST.
ABOVE MENTIONED SHORTWAVE TROUGH AND INCREASING MID LEVEL WARM AIR
ADVECTION PATTERN ALONG WITH INCREASING JET LIFT COULD CAUSE SOME
ISOLATED THUNDERSTORMS OVER THE MOST OF THE AREA. SO PULLED THE
SLIGHT CHANCE FURTHER EAST DURING THE NIGHT.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 446 AM MDT THU AUG 8 2013
UPPER PATTERN THIS PERIOD WILL SLOWLY EVOLVE FROM AN ELONGATED
EAST-WEST UPPER HIGH OVER THE SOUTHERN U.S. TO A HIGH CENTERED OVER
NEW MEXICO AND A SUBSEQUENT GRADUAL BUILDING OF HEIGHTS OVER THE
CENTRAL ROCKIES. MEANWHILE...UPPER LOWS WILL REMAIN ANCHORED OFF
THE PAC NW COAST AND NEAR JAMES BAY...RESULTING IN WEAK TO MODERATE
NORTHWEST FLOW ALOFT ACROSS THE NORTHERN AND CENTRAL PLAINS. A FEW
WEAK SHORT WAVE TROUGHS WILL LIFT OUT OF THE WEST COAST TROUGH AND
RIDE OVER THE TOP OF THE ROCKIES RIDGE...PROVIDING A FEW
OPPORTUNITIES FOR PRECIP NEXT WEEK AS THEY EMERGE ONTO THE PLAINS.
CURRENT GUIDANCE SUGGESTS THE MON-TUE TIME FRAME WILL PROVIDE
SOMEWHAT BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS...AND THIS IS
INDICATED WITH 30-40 POPS COMPARED TO 20 POPS ON REMAINING DAYS.
NORTHWEST FLOW ALOFT WILL BRING A SURFACE CANADIAN AIRMASS DOWN NEXT
WEEK SUGGESTING HIGH TEMPERATURES WILL REMAIN SEASONAL IN THE 80S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 549 AM MDT THU AUG 8 2013
COMPLEX AND UNCERTAIN SET OF TAFS. MODEL PERFORMANCE HAS BEEN POOR
TONIGHT WITH THE HRRR FINALLY HAVING SOME GLIMMER AS TO WHAT
REALITY IS. AT THIS TIME EXPECT THE WORST CONDITIONS TO BE AT
KGLD. AT KGLD HAVE IFR CONDITIONS DUE TO STRATUS. HOWEVER THAT MAY
LIFT WITH THE APPROACHING OF PRECIPITATION. AS IT STANDS NOW IFR
CEILINGS ARE EXPECTED FOR MOST OF THE PERIOD AT KGLD. RAINFALL
ENDS AT KGLD BY LATE AFTERNOON INTO EARLY EVENING WITH FOG THEN
DEVELOPING. VFR CONDITIONS ARE EXPECTED AT KMCK UNTIL EARLY THIS
EVENING IFR TO MVFR CONDITIONS ARE EXPECTED TO OCCUR.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR KSZ027>029-041-042.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...DLF
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
446 AM MDT THU AUG 8 2013
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 446 AM MDT THU AUG 8 2013
FORECAST CONCERNS WILL BE THREAT OF HEAVY RAINFALL AND CHANCES OF
PRECIPITATION. SATELLITE SHOWING LITTLE CHANGE AS A COMPLEX AND
AMPLIFIED PATTERN FROM THE CENTRAL PACIFIC INTO NORTH AMERICA
REMAINS IN PLACE. COMPLEX AND SLOW MOVING UPPER HAS MOVED INTO
COLORADO AND NEW MEXICO. SEVERAL SHORTWAVE TROUGHS ROTATING AROUND
THIS MAIN SYSTEM. AIR MASS REMAINS MOIST THROUGH A DEEP LAYER.
PERSISTENT FRONTAL BOUNDARY REMAINS DRAPED TO OUR SOUTH AND WEST.
AT JET LEVEL...THE CANADIAN AND THE UKMET INITIALIZED BEST ON THE
JET THAT IS OVER/NEAR OUR AREA. AT MID LEVELS...SATELLITE AND UPPER
AIR ANALYSIS SHOW THAT THE ECMWF/CANADIAN FOLLOWED BY THE GFS ARE
HANDLING CURRENT SYSTEM THE BEST. SREF AND RUC WERE DOING BEST AT
THE SURFACE.
COMPLICATED AND DIFFICULT PRECIPITATION FORECAST MADE MORE DIFFICULT
BY THE FACT THAT MOST IF NOT ALL THE MODEL OUTPUT HAS CURRENT
PRECIPITATION SHIELD TOO FAR SOUTH AND IS BASICALLY IGNORING IT.
TODAY/TONIGHT...WEAK RIGHT REAR QUADRANT OF THE UPPER JET REMAINS
OVER THE AREA FOR MOST OF THE DAY. MODELS ARE IN A LITTLE MORE
DISAGREEMENT ON HOW FAST TO MOVE THIS SEGMENT EAST. ALTHOUGH THE
GENERAL TREND IS TO HAVE THIS SLOWER/FURTHER WEST THAN THE PREVIOUS
TWO DAYS. THE SLOWEST OF THE MODELS DO NOT TAKE THIS RIGHT REAR
QUADRANT TO THE EAST OF THE FORECAST AREA UNTIL BETWEEN 06Z AND 12Z.
BASED ON CURRENT SATELLITE...LATEST ECMWF IS CATCHING THE POSITION
AND COMPLEXITY OF THE UPPER TROUGH THE BEST. CONSIDERING THE
POSITION OF THE 700 MB LOW CIRCULATION...MODELS INDICATING WARM
ADVECTION/UPGLIDE IN ADVANCE OF IT...PLUS STRONG UPPER DIVERGENCE
INDICATED THE EASTERN PORTION OF THE AREA...BELIEVE THE CURRENT
PRECIPITATION WILL CONTINUE TO MOVE AND DEVELOP AND MAINLY AFFECT
THE EASTERN THIRD TO HALF OF THE FORECAST AREA.
THIS LOOKS TO BE THE BEST AREA FOR MODERATE TO HEAVY RAINFALL TO
CONTINUE THROUGH AT LEAST THIS AFTERNOON. GREELEY AND WALLACE
COUNTIES APPEAR TO BE ON THE EDGE THIS AREA AT THIS TIME. HOWEVER...
BOTH OF THOSE COUNTIES...ESPECIALLY WALLACE...GOT AT LEAST 2 TO 5
INCHES OF RAINFALL LAST. SO BELIEVE CHEYENNE COUNTY COLORADO DID
NOT RECEIVE A LOT OF HEAVY RAINFALL AND DO NOT EXPECT IT TODAY...
REMOVED THEM FROM THE FLASH FLOOD WATCH. KEPT THE REMAINDER IN THE
WATCH AND EXTENDED IT THROUGH THE AFTERNOON HOURS DUE TO THE SLOW
PROGRESSION OF THE SYSTEM ACROSS THE AREA.
QUESTION THEN BECOMES HOW FAR WEST TO BRING THE PRECIPITATION. THE
ECMWF IS SHOWING WRAP AROUND PRECIPITATION AND THE HRRR INDICATING
THE SAME IDEA. VERY INTERESTING OCCURRENCE FOR THIS TIME OF YEAR.
CURRENT RADAR TRENDS WOULD INDICATE THIS IS TAKING PLACE. SO KEPT
HIGHER POPS FURTHER WEST AS A RESULT. OVERALL...IF THE ECMWF IS RIGHT
AND IT IS SUPPORTED BY THE GEFS...THIS RAINFALL...EVEN AFTER THE
INTENSITY LETS UP...WILL BE SLOW TO END AND WILL PROBABLY NOT DO SO
UNTIL LATE TONIGHT. DID NOT INSERT AT THIS TIME BUT FOG WILL BE
POSSIBLE IF RAIN QUITS SOONER AND CLEARING CAN OCCUR.
LOWERED MAXES TODAY DUE TO CONTINUED PRECIPITATION AND THICK CLOUD
COVER.
FRIDAY/FRIDAY NIGHT...INTEREST PATTERN CONTINUES. THE ECMWF SHOWING
IT MORE BUT ALSO INDICATED BY THE OTHER MODELS AND GEFS OUTPUT...
MID LEVEL TROUGH REMAINS NEAR TO OVER THE AREA WITH WHAT LOOKS TO BE
A DECENT AMOUNT OF MOISTURE LEFT. ALSO A LEFT FRONT QUADRANT OF A
SOUTHERN JET BECOMES ESTABLISHED OVER THE AREA...ESPECIALLY THE
SOUTHEAST HALF...BY THE MIDDLE OF THE DAY. THIS CONTINUES TO AFFECT
THE AREA...ESPECIALLY THE SOUTHERN HALF...THROUGH THE ENTIRE NIGHT.
SO INSERTED POPS WITH THE HIGHEST IN THE SOUTHEAST PORTION. WITH
PERSISTENT CLOUD COVER AND UNFAVORABLE SURFACE WINDS...TRENDED
MAXES DOWN A LITTLE. IF ENOUGH CLEARING CAN OCCUR AND WITH THE MOIST
AIR MASS AND WET GROUND IN PLACE...WOULD NOT BE SURPRISED TO SEE FOG
DEVELOP.
SATURDAY/SATURDAY NIGHT...SOME DIFFERENCE IN THE JET STRUCTURE
THROUGH THE DAY. AS A RESULT IT LOOKS LIKE SOME OR MOST OF THE AREA
COULD GET LIFT FROM THE JET IN THE AREA. MID LEVEL RIDGE MOVES A
LITTLE EAST WITH A SHORTWAVE TROUGH APPROACHING FROM THE WEST IN THE
AFTERNOON. LEE TROUGH STRENGTHENS WITH SOUTHERLY WINDS INCREASING.
POSSIBILITY OF SOME SURFACE CONVERGENCE IN THE FAR WEST. SO PUT IN
A SLIGHT CHANCE IN THE FAR WEST.
ABOVE MENTIONED SHORTWAVE TROUGH AND INCREASING MID LEVEL WARM AIR
ADVECTION PATTERN ALONG WITH INCREASING JET LIFT COULD CAUSE SOME
ISOLATED THUNDERSTORMS OVER THE MOST OF THE AREA. SO PULLED THE
SLIGHT CHANCE FURTHER EAST DURING THE NIGHT.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 446 AM MDT THU AUG 8 2013
UPPER PATTERN THIS PERIOD WILL SLOWLY EVOLVE FROM AN ELONGATED
EAST-WEST UPPER HIGH OVER THE SOUTHERN U.S. TO A HIGH CENTERED OVER
NEW MEXICO AND A SUBSEQUENT GRADUAL BUILDING OF HEIGHTS OVER THE
CENTRAL ROCKIES. MEANWHILE...UPPER LOWS WILL REMAIN ANCHORED OFF
THE PAC NW COAST AND NEAR JAMES BAY...RESULTING IN WEAK TO MODERATE
NORTHWEST FLOW ALOFT ACROSS THE NORTHERN AND CENTRAL PLAINS. A FEW
WEAK SHORT WAVE TROUGHS WILL LIFT OUT OF THE WEST COAST TROUGH AND
RIDE OVER THE TOP OF THE ROCKIES RIDGE...PROVIDING A FEW
OPPORTUNITIES FOR PRECIP NEXT WEEK AS THEY EMERGE ONTO THE PLAINS.
CURRENT GUIDANCE SUGGESTS THE MON-TUE TIME FRAME WILL PROVIDE
SOMEWHAT BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS...AND THIS IS
INDICATED WITH 30-40 POPS COMPARED TO 20 POPS ON REMAINING DAYS.
NORTHWEST FLOW ALOFT WILL BRING A SURFACE CANADIAN AIRMASS DOWN NEXT
WEEK SUGGESTING HIGH TEMPERATURES WILL REMAIN SEASONAL IN THE 80S.
&&
.AVIATION....FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1110 PM MDT WED AUG 7 2013
AS TEMPERATURES COOL TO SATURATION...LOW CEILINGS SHOULD BECOME
PREDOMINANT BY SUNRISE...WITH OCCASIONAL REDUCTIONS IN VISIBILITY
IN LIGHT RAIN AND/OR FOG. FLIGHT CATEGORIES WILL BE SLOW TO
IMPROVE THURSDAY WITH MOIST CONDITIONS AND LIGHT SOUTHERLY WINDS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...FLASH FLOOD WATCH UNTIL 11 PM MDT /MIDNIGHT CDT/ THIS EVENING
FOR KSZ027>029-041-042.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...DLF
AVIATION...024
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
403 AM CDT Thu Aug 8 2013
...UPDATED LONG TERM SECTION...
.SYNOPSIS...
ISSUED AT 1010 PM CDT WED AUG 7 2013
The 08.00Z 250 hPa showed 50 KT flow extending from KDDC increasing
to around 100 KT at KAPX. @ 500 hPa, a 577-580 decameter cyclone was
spinning off northwest California. Downstream, an open wave was moving
across the central Rockies. A huge 550 decameter cyclone was noted across
west central Ontario. @ 700 hPa, easterly upslope flow was observed
at KDDC. This upslope flow also continued at 850 hPa and down to the
sfc. The precipitable water for KDDC was 1.41" (above the 75th percentile
for a Gaussian distribution). At the sfc, a stationary front was located
across the KS/OK state border. KDDC WSR-88D was busy indicating an
MCS to the west.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 254 AM CDT THU AUG 8 2013
...Pretty busy shift this morning. Most of the attention was paid to
overnight convection and then some to this afternoon...
This morning:
A fairly significant rain event occurred through the overnight period.
Rainfall reports have been pretty sparse given the fact that it is O`Dark
Thirty. We should get more reports by dawn. A few reports have trickled
in with 3.00" in Hugoton, 1.50" by Richfield, and a few flash flooding
reports. Here at the KDDC airport as of 07:24Z, we have had a measly
half of an inch. Southern Ford county and other areas probably saw 2"
to 4" via estimation from radar. Anyway, given the initial event, canceled
the Flood Watch and issued a Flash Flood Watch instead. So, why all
the precip? Well, an upper level wave, 850 hPa theta-e advection, pwats
around the 75th percentile, sfc-700 hPa upslope flow, and isentropic
lift was the impetus for MCS formation. For the rest of the early morning,
will taper precipitation probability percentage points west to east
via radar trends and HRRR guidance. FWIW, the 00Z NAM performed poorly
for the event.
Will carry the FF.A (Flash Flood Watch) until 18Z.
Today/tonight:
We should see some break in the precipitation from the morning activity
to possible additional activity later this afternoon as temporary subsidence
builds in the wake of the departing MCS. Forecast skew-t/log-p`s show
pwats still in the 1.50-1.70" range this afternoon. A moist upslope
flow will also continue from the sfc up through 800 hPa. The main synoptic
wave mentioned in the synopsis will have translated over western Kansas by
afternoon, and this will provide some upper level support for additional
lift. The atmosphere will become unstable again with 1000-2000 J/kg
of SBCAPE. Low to mid level lapse rates are fairly moist adiabatic,
so the CAPE profile is fairly skinny. Bulk shear vectors are SW/40 KT.
All and all, tomorrow does not look that impressive for severe weather
(supercells etc). What does look more promising is another MCS. There
is significant questions in regarding convective initiation/placement.
The ECMWF and both cores of the WRF look reasonable. The atmosphere
could be "worked over" from the morning convection, so a lack of additional
activity is also possible. Anywho, will carry chance precipitation probabilities
this afternoon and ramp them up to likely region wide by tonight. Maximums
will be in the 70sF and minimums in the 60sF.
.LONG TERM...(Friday through Wednesday)
ISSUED AT 353 AM CDT THU AUG 8 2013
A shortwave trough will move across the central plains reaching
the lower Missouri River Valley by late Friday with shortwave
ridging moving into the western plains. This will provide a break
in precipitation chances from late Friday into Saturday night with
surface ridging across Kansas. Low level moisture will still be
around, however, given all the saturated ground providing ample
evapotranspiration...so dewpoint temperatures will remain int he
60s for the most part despite there being some mid level
subsidence. Some subtropical jet energy will begin to move into
the desert Southwest region impinging on the southern Rockies by
Sunday night into early next week...and this is when precipitation
chances will once again be on the increase. As far as the grids
go...no changes were made to the forecast and the latest all-blend
guidance was used for the Sunday-Thursday time frame.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
ISSUED AT 1212 AM CDT THU AUG 8 2013
MVFR cigs expected through the overnight with VFR cigs after 15Z
or so. NE-E 8-11 KT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 75 63 78 61 / 60 70 20 10
GCK 74 61 77 57 / 60 70 20 10
EHA 77 62 80 60 / 60 70 10 10
LBL 79 63 80 61 / 60 70 20 10
HYS 74 62 76 61 / 100 70 30 10
P28 80 67 81 65 / 100 80 30 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH until 1 PM CDT /Noon MDT/ this afternoon FOR
KSZ030-031-043>046-061>066-074>081-084>090.
&&
$$
SYNOPSIS...Sugden
SHORT TERM...Sugden
LONG TERM...UMSCHEID
AVIATION...Sugden
AREA FORECAST DISCUSSION
NWS WICHITA KS
328 AM CDT THU AUG 8 2013
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 328 AM CDT THU AUG 8 2013
TODAY & TONIGHT:
AS ALL OBVIOUSLY KNOW...FLOODING TO CONTINUE BEINGING THE HIGHLIGHT OF
FOR PERIODS AS FLOOD WATCH REMAINS IN EFFECT TIL 7 AM FRIDAY.
DURING THE NIGHT A POORLY-DEFINED STATIONARY FRONT WAS DRAPED IN AN E-W
MANNER GENERALLY THROUGH CNTRL OK WITH A WEAK 700-MB TROF SITUATED FROM
THE UT/CO BORDER TO ~CA/AZ BORDER. WITH THE TROF SLOWLY EVOLVING INTO A
WEAK LOW AS IT VENTURES E TO WRN KS RICH & DEEP MOISTURE WILL CONTINUE
TO SPREAD NE ACROSS KS. WITH THE MID-LVL "KICKER" LACKING THE SFC-850MB
FRONTS WILL MOVE VERY LITTLE...IF AT ALL...THEREBY PROMOTING BROAD ECHO
TRAINING OVER KICT COUNTRY WHICH IN TURN WOULD EXACERBATE THE FLOODING
SITUATION ACROSS THE CWA. ONLY CHANGES TO INHERITED FORECAST WERE TO
SHIFT THE POP GRADIENT TO GENERALLY A N/S ORIENTATION TO BETTER ALIGN
WITH THE BROAD LWR-MID DECK MOISTURE CHANNEL. ASSIGNED 80-100% TO CNTRL
& SC KS THIS MORNING WITH HIGHEST POPS & ASSOCIATED TSRA SHIFTED E OVER
SE KS THIS AFTERNOON AS HRRR DEPICTS. PW`S REMAIN IN 175-200% RANGE SO
CONTINUED TO HIT QPFS HARD.
FRI & FRI NIGHT:
A FAIRLY BROAD UPR-DECK RIDGE IS FORECAST MOVE SLOWLY MOVG E TOWARD THE
CNTRL ROCKIES...THE WEAK MID-LVL LOW WILL GET FORCED E TOWARD...THEN
ACROSS...ERN KS. THIS WOULD THEREFORE SHIFT BULK OF +TSRA E ACROSS THE
KS/MO BORDER ON FRI WITH -TSRA CONFINED FROM GENERALLY THE FLINT HILLS
E FRI NGT. AS SUCH WILL CONTINUE TO SCHEDULE THE FLOOD WATCH TO END AT
7AM FRI.
SAT & SAT NGT:
MOST AREAS WILL EXPERIENCE AN INTERMISSION FROM TSRA. A FEW TSRA SHOULD
VENTURE TOWARD THE WRN CORRIDOR SAT NGT AS WEAK LWR-DECK TROFFING
BEGINS ALONG THE FRONT RANGE.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 328 AM CDT THU AUG 8 2013
ALL AREAS TO BE UNDER A WEAK NW FLOW REGIME FOR MOST OF THESE PERIODS.
A WEAK COLD FRONT WILL VENTURE SE TOWARD & PERHAPS ACROSS KICGT COUNTRY
EARLY NEXT WEEK WHICH WOULD INCREASE TSRA CHANCES FOR MUCH OF THESE
PERIODS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1137 PM CDT WED AUG 7 2013
MAIN MCS STRETCHING FROM WESTERN KS INTO WESTERN OK WILL TRACK
EASTWARD ACROSS CENTRAL/SOUTH CENTRAL/SOUTHEAST KS LATE TONIGHT
INTO THE EARLY MORNING HOURS THURSDAY. STRONGEST ACTIVITY COULD
PRODUCE SOME GUSTY WINDS/HEAVY RAIN AT HUT AND ICT FROM 08-12Z.
SHOWERS/STORMS COULD REDEVELOP AND BECOME FAIRLY WIDESPREAD LATER
THURSDAY AFTERNOON INTO THURSDAY NIGHT WITH SOME VSBY/CIG
REDUCTIONS INTO AT LEAST THE MVFR RANGE AT TIMES.
JMC
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 80 68 79 65 / 100 90 40 10
HUTCHINSON 78 65 76 63 / 100 90 40 10
NEWTON 78 66 76 63 / 100 90 50 10
ELDORADO 79 67 79 64 / 100 90 50 20
WINFIELD-KWLD 82 70 82 66 / 100 70 30 10
RUSSELL 77 63 76 62 / 100 70 40 10
GREAT BEND 77 63 75 61 / 100 80 40 10
SALINA 78 65 77 63 / 100 80 50 10
MCPHERSON 78 65 76 63 / 100 80 50 10
COFFEYVILLE 85 71 86 68 / 80 80 40 20
CHANUTE 81 69 81 66 / 80 80 60 20
IOLA 80 68 80 66 / 80 80 70 20
PARSONS-KPPF 83 70 84 67 / 80 80 50 20
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH THROUGH FRIDAY MORNING FOR KSZ032-033-047>053-
067>072-082-083-091>096-098>100.
&&
$$
ES
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
254 AM CDT Thu Aug 8 2013
...Update to short term discussion...
.SYNOPSIS...
ISSUED AT 1010 PM CDT WED AUG 7 2013
The 08.00Z 250 hPa showed 50 KT flow extending from KDDC increasing
to around 100 KT at KAPX. @ 500 hPa, a 577-580 decameter cyclone was
spinning off northwest California. Downstream, an open wave was moving
across the central Rockies. A huge 550 decameter cyclone was noted across
west central Ontario. @ 700 hPa, easterly upslope flow was observed
at KDDC. This upslope flow also continued at 850 hPa and down to the
sfc. The precipitable water for KDDC was 1.41" (above the 75th percentile
for a Gaussian distribution). At the sfc, a stationary front was located
across the KS/OK state border. KDDC WSR-88D was busy indicating an
MCS to the west.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 254 AM CDT THU AUG 8 2013
...Pretty busy shift this morning. Most of the attention was paid to
overnight convection and then some to this afternoon...
This morning:
A fairly significant rain event occurred through the overnight period.
Rainfall reports have been pretty sparse given the fact that it is O`Dark
Thirty. We should get more reports by dawn. A few reports have trickled
in with 3.00" in Hugoton, 1.50" by Richfield, and a few flash flooding
reports. Here at the KDDC airport as of 07:24Z, we have had a measly
half of an inch. Southern Ford county and other areas probably saw 2"
to 4" via estimation from radar. Anyway, given the initial event, canceled
the Flood Watch and issued a Flash Flood Watch instead. So, why all
the precip? Well, an upper level wave, 850 hPa theta-e advection, pwats
around the 75th percentile, sfc-700 hPa upslope flow, and isentropic
lift was the impetus for MCS formation. For the rest of the early morning,
will taper precipitation probability percentage points west to east
via radar trends and HRRR guidance. FWIW, the 00Z NAM performed poorly
for the event.
Will carry the FF.A (Flash Flood Watch) until 18Z.
Today/tonight:
We should see some break in the precipitation from the morning activity
to possible additional activity later this afternoon as temporary subsidence
builds in the wake of the departing MCS. Forecast skew-t/log-p`s show
pwats still in the 1.50-1.70" range this afternoon. A moist upslope
flow will also continue from the sfc up through 800 hPa. The main synoptic
wave mentioned in the synopsis will have translated over western Kansas by
afternoon, and this will provide some upper level support for additional
lift. The atmosphere will become unstable again with 1000-2000 J/kg
of SBCAPE. Low to mid level lapse rates are fairly moist adiabatic,
so the CAPE profile is fairly skinny. Bulk shear vectors are SW/40 KT.
All and all, tomorrow does not look that impressive for severe weather
(supercells etc). What does look more promising is another MCS. There
is significant questions in regarding convective initiation/placement.
The ECMWF and both cores of the WRF look reasonable. The atmosphere
could be "worked over" from the morning convection, so a lack of additional
activity is also possible. Anywho, will carry chance precipitation probabilities
this afternoon and ramp them up to likely region wide by tonight. Maximums
will be in the 70sF and minimums in the 60sF.
.LONG TERM...(Thursday night through Wednesday)
ISSUED AT 228 PM CDT WED AUG 7 2013
Medium range models indicate little change to the overall large
scale pattern through early next week with a low amplitude upper
level ridge remaining in place across the central and southern
Rockies. Early in the period, a significant upper level shortwave
is expected to eject out of the southern Rockies east-northeast
into the western high plains bringing the possibility for more
showers and thunderstorms to portions of western Kansas Thursday
night into early Friday. As the shortwave approaches, a prevailing
surface low across the Texas panhandle and an attendant frontal
boundary extending generally east across northern Oklahoma, will
provide increased lift within a low level convergence zone generally
along and just north of the Kansas border. Although the flow aloft
will remain fairly weak, a few showers and isolated thunderstorms
will be possible across much of southwest and central Kansas with
enough instability present as surface dewpoints remain well up into
the 60s(F).
A brief break in precip chances is expected generally Friday night
into Saturday as surface high pressure migrates southward into
western Kansas pushing a frontal boundary just to our south further
down into west Texas and southern Oklahoma. Chances for
thunderstorms will return to portions of western Kansas Sunday as
the weak upper level ridge begins to build across the Rockies
returning a westerly flow aloft to the western high plains. In
response, the frontal boundary well to our south is expected to
return northward providing the focus for thunderstorm development
across the region into early next week.
Below normal temperatures are likely Friday as the aforementioned
surface low in the Texas panhandle pushes off to the east setting up
a more north to northeasterly low level flow across western Kansas.
Slightly cooler air will filter down into western Kansas with H85
temperatures ranging from the mid teens(C) across central Kansas to
near 20C in far southwest Kansas. Along with increased clouds, look
for highs only up into the 70s(F) to possibly near 80F across much
of central and southwest Kansas Friday afternoon. A gradual warming
trend is then expected through the weekend as the upper level
ridging in the intermountain west begins to amplify. Highs back up
into the 80s(F) to near 90F are likely over the weekend.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
ISSUED AT 1212 AM CDT THU AUG 8 2013
MVFR cigs expected through the overnight with VFR cigs after 15Z
or so. NE-E 8-11 KT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 75 63 78 61 / 60 70 20 10
GCK 74 61 77 57 / 60 70 20 10
EHA 77 62 80 60 / 60 70 10 10
LBL 79 63 80 61 / 60 70 20 10
HYS 74 62 76 61 / 100 70 30 10
P28 80 67 81 65 / 100 80 30 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH until 1 PM CDT /Noon MDT/ this afternoon FOR
KSZ030-031-043>046-061>066-074>081-084>090.
&&
$$
SYNOPSIS...Sugden
SHORT TERM...Sugden
LONG TERM...JJOHNSON
AVIATION...Sugden
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1114 PM MDT WED AUG 7 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 221 PM MDT WED AUG 7 2013
LATEST WV IMAGERY AND RAP H5 ANALYSIS INDICATES ZONAL FLOW STILL IN
PLACE ACROSS THE CONUS WITH STRONG CLOSED LOW OVER CENTRAL CANADA.
AN EMBEDDED H5/H7 LOW IN IN PLACE UPSTREAM OF THE CWA OVER THE FOUR
CORNER REGION.
LARGE SCALE FORCING AND MID LEVEL MOISTURE CONTINUE TO ADVECT INTO
THE CWA FROM THE SOUTHWEST AHEAD OF THE FOUR CORNERS TROUGH. RAP
ANALYSIS STILL SHOWS 500-1500 J/KG OF MUCAPE IN PLACE...SO
THUNDERSTORMS ARE CERTAINLY POSSIBLE. AT THIS POINT OVERALL THREAT
FOR SEVERE THUNDERSTORMS SEEMS LOW. MODELS CONTINUE TO PAIN BULLS EYE
OF 0.50+ QPF...FAVORING SOUTHERN LOCATIONS. AT THE SAME
TIME...NAM/SREF HAVE TRENDED FURTHER NORTH WHICH DOES SEEM TO HAVE
SUPPORT LOOKING AT LATEST RADAR TRENDS. I ADJUSTED POPS ACCORDINGLY.
RAP INDICATES PWATS IN EXCESS OF 1.3"...AND WHILE LOWER THAN THE LAST
FEW DAYS IS STILL CLIMATOLOGICALLY HIGH. BASED ON RADAR/SATELLITE
TRENDS...AND THE NATURE OF THIS PATTERN...I AM CURRENTLY EXPECTING
SEVERAL PERIODS OF SHOWERS/THUNDERSTORMS ROTATING ACROSS OUR CWA
THROUGH TONIGHT...BEFORE THE MAIN TROUGH MOVES ACROSS THE REGION. AS
THIS OCCURS WE MIGHT SEE OUR BEST CHANCE FOR HEAVY PRECIP ACROSS
MOST OF THE CWA. THERE IS STILL SOME INDICATION THIS COULD OCCUR
LATER IN THE DAY THURSDAY...HOWEVER CONSENSUS SUPPORTS A MORNING
TROUGH PASSAGE AND DECREASING CHANCES THROUGH MIDDAY THURSDAY.
REGARDING WATCH...CONSIDERING THE LIKELIHOOD THAT PRECIPITATION WILL
REMAIN LIGHT TO MODERATE ACROSS MOST OF THE AREA WITH HIGHEST
TOTALS SPREAD OUT OVER 6-12HR PERIOD...I AM STARTING TO QUESTION
THE POTENTIAL FOR FLASH FLOODING. LATEST 6HR FLASH FLOOD GUIDANCE IS
GENERALLY IN THE 2-3 INCH RANGE OVER THE WATCH AREA AND UNLESS WE CAN
GET A STRONG THUNDERSTORM EMBEDDED WITHIN THE LARGER AREA OF
LIGHT-MODERATE RAIN IM NOT SURE WE WILL SEE THESE RATES. WE MAY BE
ABLE TO CANCEL THE WATCH LATER THIS EVENING...BUT I WOULD RATHER
WAIT AND SEE HOW CONVECTION EVOLVES.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 221 PM MDT WED AUG 7 2013
THURSDAY EVENING THE UPPER LEVEL SHORT WAVE TROUGH WILL MOVE EAST OF
THE AREA. WITH THE NOSE OF THE LOW LEVEL JET OVER THE EASTERN PART
OF THE AREA AS WELL...AND A WEAK RIGHT ENTRANCE REGION OF THE 300MB
JET OVER THE AREA...THERE MAY BE SOME LINGERING PRECIP. ACTIVITY
AHEAD OF THE EXITING TROUGH. MEANWHILE BEHIND THE TROUGH DRIER AIR
WILL BE MOVING IN WHICH WILL CAUSE PRECIP. CHANCES TO DECLINE FROM
WEST TO EAST. HOWEVER WITH COOLER AIR MOVING IN THERE WILL BE SOME
INSTABILITY LINGERING BEHIND THE TROUGH. WITH SOME MUCH SMALLER
UPPER LEVEL DISTURBANCES MOVING THROUGH BEHIND THE MAIN
FEATURE...ISOLATED STORMS CANNOT BE RULED OUT DURING THE EVENING AND
INTO THE OVERNIGHT HOURS.
FRIDAY ANOTHER UPPER LEVEL SHORT WAVE TROUGH WILL DEVELOP OVER FAR
EASTERN COLORADO IN THE LATE AFTERNOON. AT THE SURFACE A TROUGH
WILL BE OVER THE WESTERN BORDER OF THE TRI-STATE AREA BENEATH THE
SHORT WAVE. WITH SURFACE CONVERGENCE AND UPPER LEVEL
LIFT...ANTICIPATE SOME STORMS DEVELOPING ALONG THE SURFACE TROUGH
DURING THE MID AFTERNOON INTO THE EARLY EVENING. MEAN STORM
MOTIONS WILL BE VERY SLOW...WITH MOTIONS TURNING FROM THE WEST TO
THE NORTH. THESE MOTIONS WILL KEEP THE STORMS CONFINED TO THE
SURFACE TROUGH. BY THE LATE EVENING ANY STORMS THAT DEVELOPED WILL
DISSIPATE AS THE ENVIRONMENT STABILIZES. THE MAIN THREAT WITH ANY
STORMS THAT DEVELOP WILL BE HEAVY RAINFALL.
SATURDAY THROUGH WEDNESDAY THE UPPER LEVEL RIDGE OVER THE SOUTHWEST
CONUS WILL SLOWLY BUILD NORTHWARD...WITH THE TRI-STATE AREA
REMAINING UNDER THE PERIPHERY OF THE RIDGE. AS A RESULT MULTIPLE
UPPER LEVEL SHORT WAVE TROUGHS WILL MOVE OVER THE AREA THROUGH THE
PERIOD. THE STRONGER TROUGHS WILL MOVE OVER THE AREA AFTER THE
WEEKEND. MEANWHILE A FRONT WILL WAFFLE BACK AND FORTH OVER THE
AREA DURING THIS PERIOD WHICH WILL CAUSE TEMPERATURES TO VARY
SOMEWHAT. AT THIS TIME RANGE DIFFICULT TO KNOW WHERE THE FRONT WILL
BE SO WILL KEEP THE CONSENSUS TEMP. FORECAST OF NEAR NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1110 PM MDT WED AUG 7 2013
AS TEMPERATURES COOL TO SATURATION...LOW CEILINGS SHOULD BECOME
PREDOMINANT BY SUNRISE...WITH OCCASIONAL REDUCTIONS IN VISIBILITY
IN LIGHT RAIN AND/OR FOG. FLIGHT CATEGORIES WILL BE SLOW TO
IMPROVE THURSDAY WITH MOIST CONDITIONS AND LIGHT SOUTHERLY WINDS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...FLASH FLOOD WATCH THROUGH THURSDAY MORNING FOR KSZ027>029-041-
042.
CO...FLASH FLOOD WATCH THROUGH THURSDAY MORNING FOR COZ092.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JTL
AVIATION...024
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1133 PM CDT Wed Aug 7 2013
.UPDATE...
Issued at 940 PM CDT WED AUG 7 2013
Increase pops based on the new runs the HRRR model. The HRRR did a
good job last night forecasting the outflow boundary propagating northeast
off the MCS and causing numerous showers and thunderstorms to
develop farther north along and and south of the boundary, from
the southern counties to north of I-70.
The greatest potential for likely
to categorical pops will remain across the southern counties with
a sharp gradient in pops from east central KS, along I-70 into
north central KS along the NE border. Northeast KS may not see any
rainfall until Thursday afternoon. Also increased pops for the southern
CWA into Thursday morning as the brunt of MCS will move across southeast
KS and the northern fringe may cause heavy rainfall across the
extreme southeast counties.
&&
.SHORT TERM...(THIS EVENING THROUGH Thursday)
ISSUED AT 331 PM CDT WED AUG 7 2013
Extensive cloud cover has kept high temperatures today mainly in
upper 70s to lower to middle 80s across the area. Diffuse boundary
has been draped E to W across the area but is difficult to find
because of very weak surface wind fields. Isolated brief showers
have popped up and quickly died where greater instability exists,
near and south of boundary. Wouldn`t expect this activity to be
more than isolated late this afternoon and evening with weak
convergence and no organized upper support.
Nearly all short range (and medium range) models now consistent in
keeping weak upper disturbance south of area, so most of northeast
quarter of KS dry overnight. Only outlier is now the 09Z SREF, and
have disregarded that in coming up with POP and QPF forecast. Thus,
have considerably decreased previous forecast POPs for tonight with
highest values across far south and west forecast area and least in
far northeast KS. Latest model runs also increase influence of
surface high pressure nosing into area from the upper
midwest/western Great Lakes. This will also inhibit chances for
thunderstorms on Thursday as well, with best chances still south and
west and lowest chances northeast. With this guidance, would not
expect any significantly heavy precipitation and very low chances
for any new flooding, or increase on current river flooding through
Thursday.
.LONG TERM...(Thursday NIGHT THROUGH Wednesday)
ISSUED AT 331 PM CDT WED AUG 7 2013
Thursday evening through Saturday...
On Thursday evening, widespread moderate to at times heavy rainfall
is expected to spread northeast through the cwa. Weak mid level flow
will allow a slow northeast progression of the main shortwave trof
and therefore prolonged duration of scattered showers and
thunderstorms in the area. Strong southerly fetch of moisture
combined with warm air overriding the h85 front is expected to
center heaviest rainfall along and just north of the axis. Latest
model runs of the GFS and NAM are beginning to focus higher qpf
values just south and east of the cwa. This will need to be
monitored for consistency in consideration of flood potential. Areas
especially south of Interstate 70 who have persistently seen
rainfall each evening and/or have had flooding issues need to be
most aware to flash flooding potential from Thursday evening into
Friday. Based on the uncertainty mentioned will defer issuing flood
watch until next issuance. Where heavy precip does develop forecast
soundings depict completely saturated columns during this period
with pwat values extending above 2 inches. Showers and thunderstorms
should gradually exit the area through the day on Friday before
surface high builds southward Friday evening. Cloud cover gradually
clearing out with exiting showers should hold temps to the upper 70s
and low 80s on Friday. Light northeast winds hover around 10 mph.
Ridge flattens out Saturday with mid level zonal flow keeping most
of the rain showers out of the area. Cool air advection filtering
southward on the backside of the cool front will keep highs quite
pleasant for August in the low 80s. Slightly drier air accompanying
the wave should alleviate dewpoints a bit into the low 60s. The 12Z
NAM and ECMWF try to redevelop scattered convection over east
central areas during the late aftn in vcnty of the frontal boundary.
With this being the only run will keep forecast dry for now and
monitor model trends in upcoming forecasts.
Saturday evening through Wednesday...
On Sunday an upper trof begins to deepen across the Ontario region.
A series of embedded waves will continue to bring off and on showers
and thunderstorm chances. GFS has pretty consistent between each run
by carrying southward a sfc trough and complex of showers and
thunderstorms southeast Sunday evening into Monday. Frontal boundary
accompanying the trough becomes nearly stationary over central
Kansas with a similar pattern for precip chances through Wednesday.
Confidence is not high after Monday as the 12Z ECMWF has been
inconsistent with the frontal boundary positioning well south of
the cwa and therefore keeping much of the period dry. Temperatures
while progged to be slightly warmer will largely depend on rainfall
and cloud cover. For now will keep highs in the low to mid 80s with
lows in the 60s.
&&
.AVIATION...(For the 06Z TAFs through 06Z Thursday Night)
Issued at 1129 PM CDT WED AUG 7 2013
The complex of storms across southwest KS may reach the TAF sites
late this morning according to some models. I may place VCTS from
16Z through 19Z. A much stronger upper disturbance will bring a
better chance for thunderstorms at the TAF sites after 3Z Friday
and I may insert a VCTS group in the TAFS for later Tonight.
Expect VFR conditions outside of possible Thunderstorms.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Gargan
SHORT TERM...PHILLIPS
LONG TERM...BOWEN
AVIATION...Gargan
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
902 PM EDT Fri Aug 9 2013
...Forecast Update...
Issued at 901 PM EDT Fri Aug 9 2013
Cluster of showers and storms currently across south central
Kentucky will continue to head off to the ENE through the next few
hours. Although trends with these storms have weakened, periods of
intense rainfall can still occur, especially with repeated
thunderstorms over the area. Use caution if traveling as flooding
problems will still be possible through late evening.
A pocket of drier air evident on water vapor imagery is working into
the region behind this last cluster of precipitation. Will go dry
for much of the late evening into the early morning hours, before
deeper moisture will again surge into the area and small chances for
a shower or storm will return. The concern for this dry period will
be for fog formation as skies will become mostly clear across much
of Kentucky. With the recent heavy rainfall, fog and even dense fog
will likely form. Actually already seeing some fog form on webcams.
Have include fog mention in the grids for now, but may need to
update if obs start showing dense fog development. As we move into
the pre-dawn hours, will likely see thicker cloud cover move back
over, which should improve the situation.
Issued at 533 PM EDT Fri Aug 9 2013
Updated the grids to reflect higher coverage of showers and storms
across SW portions of the CWA. Issued a Flood Advisory for areas
around Bowling Green as some training of showers and storms with
rainfall rates over 2 inches per hour at times will overspread the
area. Will need to watch for Flash Flood Warnings in the region over
the next couple of hours. Will also keep our eye on a cluster of
storms moving into the western fringes of our CWA in a couple of
hours. A few severe reports have come from the strongest storm,
however expect a weakening trend as the cluster moves in. Overall,
will mention numerous showers and storms early this evening in areas
where the biggest clusters are located, with isolated to scattered
coverage elsewhere. Please be aware that very heavy rainfall is
likely with any shower or storm and quick ponding of water on
roadways will occur.
.SHORT TERM (Now through Saturday Night)...
Issued at 305 PM EDT Fri Aug 9 2013
A line of showers and thunderstorms have begun to form along the
frontal boundary, currently draped along the Ohio River. As has been
the case this week, these are efficient rain producers, dumping a
lot of rain in a short amount of time. Traffic cameras in the
Louisville metro along with obs from SDF confirm the reduced
visibilities accompanying these cells. Thankfully, the line has been
moving relatively quickly off to the east-southeast so unless the
line really fills in, setting up a potential training effect,
flooding shouldn`t be a major concern, especially in north-central
KY where the rain has been much more hit and miss as of late. If it
is able to hold together and makes its way into the Bluegrass
region, there could be some localized problems since FFG is much
lower there due to the recent heavy rains and already saturated
soils. Unfortunately, the models aren`t handling it very well with
the exception of the latest NAM (but its performance this week has
been less than stellar) so its tough to get a solid idea of how this
will play out. While the HRRR doesn`t necessarily depict it well,
this has been one of the top performing models under this regime
and its showing scattered cells developing across much of the center
of the commonwealth. Later tonight, a mid-level wave traverses
through and the HRRR grabs onto it, bringing a cluster of showers
and embedded thunderstorms through northern KY and southern IN. This
may be a bit bullish but it would be the last hurrah for the
northern half of the forecast area as the boundary slowly sinks
south (assuming this scenario holds true).
By tomorrow, the focus for convection shifts to the south once again
along the quasi-stationary boundary. As it stands right now, any
storms that fire up during the heat of the day (despite the
continued cloud cover) should wane after sunset Saturday, allowing
for most of the area to remain dry. Under light to calm winds and
lingering low-level moisture, patchy fog could be a factor for not
only tonight (wherever it doesn`t rain) but for tomorrow night as
well. Overnight lows for both nights will range from the upper 60s
to the lower 70s from north to south, respectively. Under the
aforementioned cloud cover, highs tomorrow will again be below
normal, primarily in the mid 80s. Expect this tropical-feeling
airmass to remain in place for the entirety of this forecast period.
.LONG TERM (Sunday through Friday)...
Issued at 312 PM EDT Fri Aug 9 2013
The start of the long term period will feature generally zonal upper
flow, which will transition to an eastern trough/western ridge by
the end of the long term period. This pattern shift will allow for
drier conditions and cooler/less humid air by the middle of next
week.
A quasi-stationary frontal boundary will be draped from southwest to
northeast across southern Kentucky on Sunday. This will serve as
the focus for showers and thunderstorms to continue, mainly across
southern Kentucky as a shortwave trough rides along the boundary and
brings enhanced vertical motion. As winds turn northerly across
southern Indiana and northern Kentucky due to incoming high
pressure, think enough dry air will work in to actually keep much of
Sunday dry for those regions.
On Sunday night, the surface high will scoot east as another
shortwave trough dives through the Great Lakes region. Guidance
suggests this wave will pull the quasi-stationary front back north
which would give much more of central and northern KY decent
rainfall chances. However, am a bit skeptical of this solution as
the progged system does not appear strong enough to force the front
northward (especially if it`s continually being convectively
reinforced further south). Therefore, the more widespread activity
will likely remain across southern KY, with a general lull in
activity across northern KY and southern Indiana. Given the
continued moist atmosphere south of the front, localized flooding
will need to continue to be watched especially if areas receive
heavy rainfall through the short term period.
By Monday night into Tuesday, another surface front will approach
from the northwest. This front looks much more progressive as the
upper-level flow begins to transition to more northwesterly. As
mentioned in the previous discussion, am a bit skeptical on just how
much moisture will remain ahead of this secondary front, thus will
continue with 30-40 pops as it passes through on Tuesday. Given
the likely moist bias in guidance, instability along this front will
be less than currently progged, thus do not expect severe weather.
However, the drier air working in will help support a few healthy
downdrafts, which may lead to some sub-severe gusts in the
heavier storm cores.
The front will clear the region by Tuesday night, allowing Canadian
high pressure to build into the Ohio Valley. This will bring
welcomed relief from the muggy airmass we have seen of late, as
temperatures fall into the upper 70s/lower 80s with dewpoints in the
50s and lower 60s. This pleasant airmass will also get rid of any
additional storm potential, with dry weather expected Wednesday
through at least the end of next week.
&&
.AVIATION (00Z TAF Update)...
Issued at 700 PM EDT Fri Aug 9 2013
Surface analysis reveals a quasi-stationary boundary extending from
Arkansas northeastward through south-central Kentucky. The boundary
is generally south of the Western Kentucky and Bluegrass Parkways
and that is where majority of the convection will be focused this
evening and into the overnight hours. For this evening, expect
showers to be in the vicinity of all three terminals. KBWG and KLEX
look to have the best shots of rainfall...mainly in the 10/00-02Z
time frame.
While the models do hint at another mid-level wave moving in
overnight, overall confidence is not all that high for several
reasons. First, the models have struggled recently with capturing
these small scale perturbations. Secondly, we`re going to be pretty
worked over from this afternoon`s convection which should limit
overall convective coverage. Main concern overnight will be fog
potential due to the afternoon rainfall. We expect visibilities and
ceilings to drop overnight especially down at KBWG where IFR to LIFR
visibilities may occur during the overnight period. MVFR vsbys and
cigs look likely at KSDF and KLEX overnight with improvement toward
10/12Z.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Updates........BJS
Short Term.....LG
Long Term......KJD
Aviation.......MJ
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
701 PM EDT Fri Aug 9 2013
...Updated Aviation Discussion...
...Forecast Update...
Issued at 533 PM EDT Fri Aug 9 2013
Updated the grids to reflect higher coverage of showers and storms
across SW portions of the CWA. Issued a Flood Advisory for areas
around Bowling Green as some training of showers and storms with
rainfall rates over 2 inches per hour at times will overspread the
area. Will need to watch for Flash Flood Warnings in the region over
the next couple of hours. Will also keep our eye on a cluster of
storms moving into the western fringes of our CWA in a couple of
hours. A few severe reports have come from the strongest storm,
however expect a weakening trend as the cluster moves in. Overall,
will mention numerous showers and storms early this evening in areas
where the biggest clusters are located, with isolated to scattered
coverage elsewhere. Please be aware that very heavy rainfall is
likely with any shower or storm and quick ponding of water on
roadways will occur.
.SHORT TERM (Now through Saturday Night)...
Issued at 305 PM EDT Fri Aug 9 2013
A line of showers and thunderstorms have begun to form along the
frontal boundary, currently draped along the Ohio River. As has been
the case this week, these are efficient rain producers, dumping a
lot of rain in a short amount of time. Traffic cameras in the
Louisville metro along with obs from SDF confirm the reduced
visibilities accompanying these cells. Thankfully, the line has been
moving relatively quickly off to the east-southeast so unless the
line really fills in, setting up a potential training effect,
flooding shouldn`t be a major concern, especially in north-central
KY where the rain has been much more hit and miss as of late. If it
is able to hold together and makes its way into the Bluegrass
region, there could be some localized problems since FFG is much
lower there due to the recent heavy rains and already saturated
soils. Unfortunately, the models aren`t handling it very well with
the exception of the latest NAM (but its performance this week has
been less than stellar) so its tough to get a solid idea of how this
will play out. While the HRRR doesn`t necessarily depict it well,
this has been one of the top performing models under this regime
and its showing scattered cells developing across much of the center
of the commonwealth. Later tonight, a mid-level wave traverses
through and the HRRR grabs onto it, bringing a cluster of showers
and embedded thunderstorms through northern KY and southern IN. This
may be a bit bullish but it would be the last hurrah for the
northern half of the forecast area as the boundary slowly sinks
south (assuming this scenario holds true).
By tomorrow, the focus for convection shifts to the south once again
along the quasi-stationary boundary. As it stands right now, any
storms that fire up during the heat of the day (despite the
continued cloud cover) should wane after sunset Saturday, allowing
for most of the area to remain dry. Under light to calm winds and
lingering low-level moisture, patchy fog could be a factor for not
only tonight (wherever it doesn`t rain) but for tomorrow night as
well. Overnight lows for both nights will range from the upper 60s
to the lower 70s from north to south, respectively. Under the
aforementioned cloud cover, highs tomorrow will again be below
normal, primarily in the mid 80s. Expect this tropical-feeling
airmass to remain in place for the entirety of this forecast period.
.LONG TERM (Sunday through Friday)...
Issued at 312 PM EDT Fri Aug 9 2013
The start of the long term period will feature generally zonal upper
flow, which will transition to an eastern trough/western ridge by
the end of the long term period. This pattern shift will allow for
drier conditions and cooler/less humid air by the middle of next
week.
A quasi-stationary frontal boundary will be draped from southwest to
northeast across southern Kentucky on Sunday. This will serve as
the focus for showers and thunderstorms to continue, mainly across
southern Kentucky as a shortwave trough rides along the boundary and
brings enhanced vertical motion. As winds turn northerly across
southern Indiana and northern Kentucky due to incoming high
pressure, think enough dry air will work in to actually keep much of
Sunday dry for those regions.
On Sunday night, the surface high will scoot east as another
shortwave trough dives through the Great Lakes region. Guidance
suggests this wave will pull the quasi-stationary front back north
which would give much more of central and northern KY decent
rainfall chances. However, am a bit skeptical of this solution as
the progged system does not appear strong enough to force the front
northward (especially if it`s continually being convectively
reinforced further south). Therefore, the more widespread activity
will likely remain across southern KY, with a general lull in
activity across northern KY and southern Indiana. Given the
continued moist atmosphere south of the front, localized flooding
will need to continue to be watched especially if areas receive
heavy rainfall through the short term period.
By Monday night into Tuesday, another surface front will approach
from the northwest. This front looks much more progressive as the
upper-level flow begins to transition to more northwesterly. As
mentioned in the previous discussion, am a bit skeptical on just how
much moisture will remain ahead of this secondary front, thus will
continue with 30-40 pops as it passes through on Tuesday. Given
the likely moist bias in guidance, instability along this front will
be less than currently progged, thus do not expect severe weather.
However, the drier air working in will help support a few healthy
downdrafts, which may lead to some sub-severe gusts in the
heavier storm cores.
The front will clear the region by Tuesday night, allowing Canadian
high pressure to build into the Ohio Valley. This will bring
welcomed relief from the muggy airmass we have seen of late, as
temperatures fall into the upper 70s/lower 80s with dewpoints in the
50s and lower 60s. This pleasant airmass will also get rid of any
additional storm potential, with dry weather expected Wednesday
through at least the end of next week.
&&
.AVIATION (00Z TAF Update)...
Issued at 700 PM EDT Fri Aug 9 2013
Surface analysis reveals a quasi-stationary boundary extending from
Arkansas northeastward through south-central Kentucky. The boundary
is generally south of the Western Kentucky and Bluegrass Parkways
and that is where majority of the convection will be focused this
evening and into the overnight hours. For this evening, expect
showers to be in the vicinity of all three terminals. KBWG and KLEX
look to have the best shots of rainfall...mainly in the 10/00-02Z
time frame.
While the models do hint at another mid-level wave moving in
overnight, overall confidence is not all that high for several
reasons. First, the models have struggled recently with capturing
these small scale perturbations. Secondly, we`re going to be pretty
worked over from this afternoon`s convection which should limit
overall convective coverage. Main concern overnight will be fog
potential due to the afternoon rainfall. We expect visibilities and
ceilings to drop overnight especially down at KBWG where IFR to LIFR
visibilities may occur during the overnight period. MVFR vsbys and
cigs look likely at KSDF and KLEX overnight with improvement toward
10/12Z.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Update.........BJS
Short Term.....LG
Long Term......KJD
Aviation.......MJ
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
649 PM EDT Thu Aug 8 2013
...Forecast Update...
Issued at 648 PM EDT Thu Aug 8 2013
Cluster of light to moderate rain showers continues to trek eastward
across portions of north-central Kentucky. This activity is
expected to continue for the next several hours, but should weaken
as it heads toward the I-75 corridor. More strongly forced
convection is rapidly developing on the southern side of a vorticity
max pushing eastward into Indiana. Storms are forming along a
differential heating and wind shift axis across southern Illinois.
This activity should continue to develop and track eastward along
the I-64 corridor this evening. Latest NAM and HRRR runs suggest
that this would impact north-central Kentucky during the overnight
period. Secondary area of storms is developing over southern MO and
northern AR, this activity will also head east, but may stay just
south of the forecast area late tonight.
With this update, have increased PoPs for the next few hours across
the central portions of the forecast area with the batch of
light-moderate rain moving through. Will continue to ramp up PoPs
tonight as the cluster of storms out to the west heads eastward into
the Ohio Valley.
.SHORT TERM (Now through Friday Night)...
Issued at 315 PM EDT Thu Aug 8 2013
An obstructed blocky flow continues over Canada late today with an
elongated west to east orientated 500mb low over Ontario and Quebec.
Farther south, a moderate westerly flow continues over the northern
Ohio Valley. Precipitable water values of near two inches or more
will continue through mid-day Friday, indicative of a tropical
airmass.
Quite a bit uncertainty still exists about where exactly convection
develops this evening. An circulation left over from last night`s
convection is now moving east northeast just to the south of St
Louis. This feature will move over southern Indiana late this
evening. This feature is supporting a cluster of thunderstorms now
moving east over western Kentucky. These storms are moving into an
unstable airmass southwest of Kentucky and should hold together
through this evening. Therefore, think storms late this afternoon
and early evening will become most numerous across west central
Kentucky, west of Interstate 65 and mostly to the south of
Interstate 64 across southern Indiana. A second area of convection
may drop south into south central Indiana late this evening. These
northern storms will form along a cold front slowly sagging south
across central Indiana. Will go likely for areas in Kentucky west of
Interstate 65 with scattered wording elsewhere.
Last night isolated storms over the Bluegrass produced very isolated
torrential rainfall amounts and flooding. This same scenario may play itself
out again tonight. Across south central Kentucky, localized heavy
rain and possible flooding are again possible in a few spots.
For Friday, a nearly stationary front will lie across southern
Indiana, nearly parallel to the Ohio River, any thunderstorm
development will highly depend on the location of any residual cloud
cover and outflow boundaries from overnight convection. Our best
moisture and convergence will lie over southern portions of our
Commonwealth. Slightly drier air will slowly filter in across
southern Indiana, limiting convective coverage there. Will continue
likely pops across southern Kentucky during the day Friday. Think
that any scattered storms will diminish across the north late
Friday, while hanging on near Tennessee.
Tonight will stay humid and muggy, with lows in the lower 70s, highs
Friday will reach the mid to upper 80s.
.LONG TERM (Saturday through Thursday)...
Issued at 309 PM EDT Thu Aug 8 2013
Quasi-stationary boundary laid out across the commonwealth will be
starting off this forecast period, allowing for the primary focus
for convection to be limited to southern portions of KY. Have
trended back PoPs for the northern half of the forecast area as such
since surface winds will have begun to back to the north by this
point, assuming the general deterministic model consensus holds
true. With the loss of daytime heating and as the front slowly
slides off to the south and east, have gone dry for the early
morning hours on Sunday. Couldn`t completely remove PoPs out of the
forecast for the afternoon hours as a surface low riding along the
frontal boundary traverses across from west to east, once again
serving as a focus for renewed convection chances as surface high
pressure centered over the southern Great Lakes fights for control
over us. This fight, however, is very short lived as the high moves
off toward the East Coast and the next frontal boundary approaches
the Ohio Valley. This front is seemingly much faster with strong
Canadian high pressure pushing it southward from behind. What this
translates to for us is a continued unsettled period from Monday
through Tuesday night. By Wednesday, am hopeful that the boundary
will be south of the TN border, although the 12Z GFS tries to keep
the southern tier of counties wet through Wednesday night. Even if
the timing ends up being slightly off, the end result will be the
same for all of us: clearing skies, a much drier airmass, and cool
temperatures for this time of year.
Speaking of temperatures, we`ll see highs ranging from the lower to
upper 80s throughout the entire period with the warmest day looking
to be Monday and the coolest day on Thursday. Dewpoints will keep it
muggy from this weekend through mid-week before a noticeable
difference comes in by Wednesday-Thursday. Lows will be near normal
Saturday night through Tuesday night, dropping off to below normal
by Wednesday night. Looking at 850mb anomalous temps on NCEP`s
ensemble, the cool temps are depicted to prevail under the
aforementioned high for much of the end of next week.
&&
.AVIATION (18Z TAF Update)...
Issued at 120 PM EDT Thu Aug 8 2013
Very humid air and a series of weak waves will bring scattered
convection across the region late this afternoon and evening.
Earlier convection around LEX will be diminishing by 18 to 19z, and
much of this evening until 01z or so should be dry.
On the other hand, scattered convection will begin to move towards
BWG after 20z and may periodically affect the terminal site through
the late evening hours. At SDF, convection will stay away from the
terminal through around 22z, after which, storms will become more
numerous late this evening towards midnight.
VFR conditions are expected at SDF through this evening, until
thunderstorms approach. At LEX and BWG, occasional broken ceilings
right around the MVFR/VFR threshold will continue through mid
afternoon, become more scattered this evening.
Winds will remain light from the southwest through early this
evening, then become light and variable overnight and Friday.
With scattered thunderstorm lasting possibly through the overnight
period, occasional MVFR visibilities and ceilings may be expected
through the morning hours. Scattered thunderstorms are possible
Friday.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Update.........MJ
Short Term.....JSD
Long Term......LG
Aviation.......JSD
AREA FORECAST DISCUSSION
NWS JACKSON KY
255 PM EDT THU AUG 8 2013
.UPDATE...
ISSUED AT 255 PM EDT THU AUG 8 2013
MOST PRECIP HAS ENDED...WITH SCATTERED SHOWERS REMAINING AT MID
AFTERNOON. WILL LOOK FOR THEM TO PERSIST INTO THIS EVENING. CLOUDS
AND PRECIP HAVE SLOWED THE TEMPERATURE CLIMB...AND HAVE LOWERED
FORECAST MAX TEMPS SLIGHTLY FOR TODAY.
UPDATE ISSUED AT 1125 AM EDT THU AUG 8 2013
HEAVY RAINFALL DID NOT MATERIALIZE OVER THE FORECAST AREA THIS
MORNING...BUT STAYED TO OUR SOUTHWEST. THE MAIN PORTION OF AN MCS
REMAINED ANCHORED IN TN...WITH JUST DEBRIS/BLOW-OFF STREAMING OVER
OUR SOUTHERN COUNTIES IN KY. NOT CONFIDENT IN HEAVY RAINFALL TODAY
THROUGH FRIDAY...BUT WILL NOT DISPUTE THAT WITH THE HIGH MOISTURE
CONTENT OF THE ATMOSPHERE...RECENT HISTORY TO OUR WEST...AND WEAK TO
MODERATE LARGELY UNIDIRECTIONAL FLOW WITH HEIGHT...THAT SOME POTENTIAL
FOR TRAINING AND HEAVY RAINFALL EXISTS. WITH FFA ALREADY IN
PLACE...WILL LEAVE IT AS IS.
HAVE REDUCED POPS A BIT FOR TODAY...HOLDING ON TO LIKELY CATEGORY IN
OUR SOUTHEAST COUNTIES WHERE NUMEROUS SHOWERS WERE ONGOING LATE THIS
MORNING...BUT ONLY USING 50 PERCENT POPS ELSEWHERE.
UPDATE ISSUED AT 628 AM EDT THU AUG 8 2013
AFTER TALKING WITH NEIGHBORING OFFICES LMK AND RLX...AS WELL AS
SEEING THE LATEST HPC QPF GUIDANCE...MADE THE DECISION TO ISSUE AN
FFA FOR THE REGION THROUGH FRIDAY EVENING. SCT CONVECTION CONTINUES
TO DEVELOP ALONG THE BOUNDARY CURRENTLY PUSHING SOUTH INTO
KENTUCKY...WITH PWAT VALUES EXPECTED TO BE IN THE 2.0 AND ABOVE RANGE
FOR A 6 HOUR TIME PERIOD BOTH THIS MORNING AND FRIDAY MORNING. WITH
SOME OF THESE SHOWERS AND THUNDERSTORMS...RAIN RATES OF 2 TO 3 INCHES
AN HOUR ARE VERY POSSIBLE. LOCALIZED FLASH FLOODING WILL BE A THREAT
THEREFORE...ESPECIALLY IN AREAS THAT HAVE MULTIPLE STORMS PASS OVER
THEIR LOCATION IN THE NEXT 48 HOURS. LATEST NAM IS ALSO TARGETING
ANOTHER SWATH OF HEAVIER PRECIP MOVING INTO THE REGION SATURDAY
MORNING...AFTER THE EXPIRATION OF THE FFA. THIS IS SUBJECT TO CHANGE
WITH LATER MODEL RUNS...SO FIGURED IT WOULD BE EASIER TO EXTEND THE
FFA IN THE FUTURE IF NEEDED RATHER THAN HAVE TO CANCEL IT AND END UP
NEEDING TO REISSUE. THE LATEST SPENES PRODUCT FROM THE SATELLITE
BRANCH ALSO PINPOINTED A LARGE SECTION OF OUR SOUTHWESTERN CWA IN
THEIR AREA OF CONCERN FOR EXCESSIVE RAINFALL THIS MORNING. THIS JUST
FURTHER SOLIDIFIED THE DECISION TO GO AHEAD AND ISSUE THE FFA FOR THE
REGION.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 413 AM EDT THU AUG 8 2013
THE COLD FRONT THAT HAS REMAINED NEARLY STATIONARY JUST NORTH OF THE
OHIO RIVER VALLEY YESTERDAY WILL FINALLY BEGIN ITS PUSH SEWARD
ACROSS KY DURING THE DAY TODAY...REACHING THE SE PORTION OF THE
STATE BY EVENING. AS WAS THE CASE WITH THIS SYSTEM YESTERDAY...HIGH
HUMIDITY VALUES IN ADDITION TO THE ISENTROPIC LIFT PROVIDED BY THIS
FRONT WILL WORK TO SPAWN CONVECTION...ESPECIALLY WITH THE ADDITION
OF DAYTIME HEATING AND GREATER INSTABILITY. EXPECT A LARGE AREA OF
SHOWERS AND POTENTIAL THUNDERSTORMS TO DEVELOP JUST AHEAD OF THE
FRONT AND ENCOMPASS MUCH OF THE CWA...THEN SHIFT SLIGHTLY EASTWARD
AS THE FRONT NEARS INTO THE REGION. CURRENT RADAR TRENDS ARE ALREADY
SUPPORTING THIS IDEA...WITH SCATTERED SHOWERS CONTINUING TO DEVELOP
ACROSS THE WESTERN HALF OF THE CWA. WHILE MODELS REMAIN FAIRLY
CONSISTENT THAT PRECIP WILL OVERSPREAD THE AREA...THERE IS STILL
SOME SUBTLE DIFFERENCES IN RESOLUTION AS TO WHERE THE HEAVIEST
PRECIP WILL OCCUR. BASED ON THE LATEST HRRR AND NAM12...EXPECT BEST
PRECIP DEVELOPMENT ACROSS THE SOUTHERN EXTENT OF THE CWA IN THE
MORNING...SPREADING TO THE NORTH BY THE AFTERNOON.
BY 0Z FRIDAY...FRONT WILL ONCE AGAIN BECOME STATIONARY...THIS TIME
PARKING ITSELF ACROSS EASTERN KY. WITH SUCH HUMID AND UNSTABLE
CONDITIONS IN PLACE...WILL CONTINUE WITH ONGOING FORECAST OF SOME
SCT CONVECTIVE POSSIBILITY THROUGHOUT THE NIGHT...SINCE ANY STORM
ONGOING IN THE AFTERNOON WILL TAKE SOME TIME TO DIE OFF...AND THERE
IS ALWAYS THE POSSIBILITY THAT ANY LITTLE AREA OF LIFT COULD
INITIATE SOME MORE SHOWERS. LUCKILY...WITH LOSS OF DAYTIME
HEATING...BEST INSTABILITY AND THUNDERSTORM POTENTIAL WILL LESSON.
HIGH DEW POINTS WILL ALSO LEAD TO LITTLE VARIATION FOR
TEMPERATURES...WITH LOWS ONLY DROPPING TO AROUND 70.
FRIDAY WILL BRING ABOUT SIMILAR CONDITIONS TO TODAY...WITH THE
STATIONARY FRONT LIFTING SLIGHTLY JUST TO THE NORTH OF THE CWA. AN
UPPER LEVEL SHORTWAVE MOVING THROUGH EASTERN KY BY FRIDAY MORNING
WILL BE ENOUGH TO KICK START SHOWER AND THUNDERSTORM DEVELOPMENT
ACROSS THE REGION. WHILE PRECIPITABLE WATER VALUES WERE NEARING 2
INCHES FOR TODAY/S FORECAST...ACCORDING TO LATEST NAM12
SOUNDINGS...FRIDAY/S SOUNDINGS ARE POINTING AT WELL OVER 2.10 INCHES
IN MANY LOCATIONS WITHIN A 6 HOUR PERIOD. IF A STRONG SHOWER OR
THUNDERSTORM DEVELOPS AND MOVES OVER A PARTICULAR SITE...FLASH
FLOODING IS A DEFINITE THREAT...ESPECIALLY IF THEY ARE IMPACTED BY
TODAY/S CONVECTIVE ACTIVITY. MOST OF THIS MOISTURE IS EXPECTED TO
FALL DURING THE MORNING AND EARLY AFTERNOON HOURS...WITH PWAT VALUES
SLIGHTLY LESS...IN THE 1.5-2.0 RANGE IN THE AFTERNOON HOURS.
TEMPERATURES SHOULD REMAIN FAIRLY SIMILAR TO TODAY WITH LITTLE
CHANGE IN THE OVERALL PATTERN.
SINCE A LOT OF THE EXPECTED PRECIP IS BASED ON MESOSCALE
DEVELOPMENT...DISCUSSED THE IDEA OF ISSUING A FFA FOR THE AREA...BUT
ULTIMATELY DECIDED TO HOLD OFF FOR RIGHT NOW. FUTURE SHIFTS MAY
DECIDE TO PULL THE TRIGGER BASED ON HOW WIDESPREAD AND HEAVY THE
DAY/S CONVECTIVE DEVELOPMENT PROVES TO BE.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 413 AM EDT THU AUG 8 2013
THE MODELS CONTINUE TO BE IN GOOD AGREEMENT ON THE GENERAL UPPER AIR
PATTERN THAT WILL GUIDE OUR WEATHER THROUGH THE EXTENDED PORTION OF
THE FORECAST. THIS CONSISTS PRIMARILY OF A DEEP AND PERSISTENT
TROUGH OVER SOUTHEAST CANADA AND A FLAT RIDGE OVER THE SOUTHERN TIER
OF THIS NATION. BETWEEN THESE...FAIRLY FAST MID LEVEL FLOW WILL
CARRY SHORT WAVE ENERGY FROM THE WEST COAST THROUGH THE OHIO VALLEY
BEFORE EXITING OFF THE EASTERN SEABOARD. THIS FLOW WILL BE FAIRLY
ZONAL OVER KENTUCKY THROUGH THE WEEKEND BEFORE A WESTERN RESURGENCE
IN THE CANADIAN TROUGH INDUCES A DIP SOUTH THROUGH THE GREAT LAKES
AND INTO THE NORTHERN OHIO VALLEY. THIS WILL RESULT IN MORE OF A
NORTHWEST FLOW PATTERN FOLLOWING THE WEEKEND INTO THE MIDDLE OF NEXT
WEEK. THE GFS AND ECMWF DIFFER MOST DURING THE LATTER PORTION OF THE
FORECAST AS THE ECMWF RUNS A BIT FASTER AND FURTHER EAST WITH THE
CANADIAN LOW/S REDEVELOPMENT INTO THE DAY MONDAY. THE GFS TAKES THE
CORE OF THIS LOW FURTHER SOUTH ON TUESDAY...DIPPING INTO THE
STATES...BEFORE LIFTING IT JUST NORTH OF EAST. DURING THIS TIME OF
LARGER GFS/ECMWF DISCREPANCY THE GEM SEEMS TO BE SIDING WITH THE
ECMWF SO THE MORE EXTREME GFS SOLUTION FOR MONDAY TO WEDNESDAY WILL
BE DISCOUNTED. ALSO...ITS RUN TO RUN CONSISTENCY HAS BEEN POOR...NOT
THAT THE ECMWF HAS BEEN ALL THAT MUCH BETTER/JUST NOT SO OUT THERE
AT TIMES...FOR THE LATTER PART OF THE EXTENDED. ACCORDINGLY...WILL
FAVOR THE BLENDED RESULTS THROUGH THE WEEKEND BEFORE LEANING MORE
TOWARD THE ECMWF INTO THE MIDDLE OF NEXT WEEK.
SENSIBLE WEATHER WILL FEATURE A CONTINUATION OF OUR WET PATTERN THAT
IS PRIMED FOR BOUTS OF HEAVY RAIN. THE SFC BOUNDARY WILL REMAIN
STALLED THROUGH THE REGION INTO THE WEEKEND WITH EACH SFC WAVE
RIPPLING PAST...POTENTIALLY SENDING THE BOUNDARY AND ITS HEAVIEST
RAIN OUR WAY. HIGH PW AIR AND DAYTIME INSTABILITY WILL PROVIDE THE
FUEL FOR THIS MCS ACTIVITY. THEREFORE...POPS WILL REMAIN HIGH INTO
THE WEEKEND WITH MAX TEMPERATURES CAPPED BELOW NORMAL DUE TO CLOUDS
AND CONVECTION. FOR THE START OF NEXT WEEK...IT LOOKS LIKE THE
AMPLIFYING TROUGH ALOFT WILL BE ENOUGH TO EVENTUALLY PUSH THE FRONT
SOUTH OF THE AREA AND ALLOW DRIER AIR TO FLOW INTO THE STATE. THE
FAVORED 12Z ECMWF DOES TAKE THE DEEPER MOISTURE SOUTH LATER MONDAY
WHILE THE GFS WAITS UNTIL A SECONDARY FRONT PUSHES THROUGH ON
TUESDAY NIGHT. WILL CONTINUE SMALL POPS INTO TUESDAY FOR THIS
TRANSITION...BUT NOT AS HIGH AS THE GFS WOULD IMPLY. HOPEFULLY
WEDNESDAY WILL TURN OUT AS PLEASANT AS THE MODEL CONSENSUS SUGGESTS
WITH A RETURN OF DECENT SUNSHINE AND MUCH DRIER AIR. WE WILL SEE...
BUT AT LEAST THIS SEEMS TO BE A BUILDING AND STABILIZING ASPECT OF
THE FORECAST FROM THE LATEST MEDIUM RANGE MODELS.
THE CR GRID LOAD CAME IN NICELY FOR THIS UNSETTLED FORECAST THROUGH
THE WEEKEND. DID TWEAK POPS TO ADD MORE OF A DIURNAL CYCLE AND ALSO
TOWARD THE LATEST SPECIFICS FROM THE 12Z ECMWF FOR MONDAY ON INTO
WEDNESDAY. ONLY MADE MINOR TERRAIN BASED ADJUSTMENTS FOR TEMPS
THROUGHOUT THE BULK OF THIS EXTENDED PERIOD GIVEN THE HIGH MOISTURE
CONTENT...AT LEAST THROUGH TUESDAY MORNING.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 255 PM EDT THU AUG 8 2013
WIDESPREAD MVFR WAS PRESENT AT THE START OF THE PERIOD. IMPROVEMENT
TO LARGELY VFR IS EXPECTED THIS AFTERNOON. HOWEVER...AREAS OF MVFR
AND IFR WILL PERSIST IN SCATTERED SHOWERS AND THUNDERSTORMS. THIS
SHOULD BE THE CASE INTO THE NIGHT. LATE TONIGHT A DETERIORATION TO
MVFR IS EXPECTED...WITH EVENTUAL IFR IN MANY AREAS ON FRIDAY MORNING.
THIS WILL OCCUR AS DUE TO THE LIKELIHOOD OF SHOWERS AND THUNDERSTORMS
DEVELOPING.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR KYZ044-050>052-
058>060-068-069-079-080-083>088-104-106>120.
&&
$$
UPDATE...HAL
SHORT TERM...JMW
LONG TERM...GREIF
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS JACKSON KY
1125 AM EDT THU AUG 8 2013
.UPDATE...
ISSUED AT 1125 AM EDT THU AUG 8 2013
HEAVY RAINFALL DID NOT MATERIALIZE OVER THE FORECAST AREA THIS
MORNING...BUT STAYED TO OUR SOUTHWEST. THE MAIN PORTION OF AN MCS
REMAINED ANCHORED IN TN...WITH JUST DEBRIS/BLOW-OFF STREAMING OVER
OUR SOUTHERN COUNTIES IN KY. NOT CONFIDENT IN HEAVY RAINFALL TODAY
THROUGH FRIDAY...BUT WILL NOT DISPUTE THAT WITH THE HIGH MOISTURE
CONTENT OF THE ATMOSPHERE...RECENT HISTORY TO OUR WEST...AND WEAK TO
MODERATE LARGELY UNIDIRECTIONAL FLOW WITH HEIGHT...THAT SOME POTENTIAL
FOR TRAINING AND HEAVY RAINFALL EXISTS. WITH FFA ALREADY IN
PLACE...WILL LEAVE IT AS IS.
HAVE REDUCED POPS A BIT FOR TODAY...HOLDING ON TO LIKELY CATEGORY IN
OUR SOUTHEAST COUNTIES WHERE NUMEROUS SHOWERS WERE ONGOING LATE THIS
MORNING...BUT ONLY USING 50 PERCENT POPS ELSEWHERE.
UPDATE ISSUED AT 628 AM EDT THU AUG 8 2013
AFTER TALKING WITH NEIGHBORING OFFICES LMK AND RLX...AS WELL AS
SEEING THE LATEST HPC QPF GUIDANCE...MADE THE DECISION TO ISSUE AN
FFA FOR THE REGION THROUGH FRIDAY EVENING. SCT CONVECTION CONTINUES
TO DEVELOP ALONG THE BOUNDARY CURRENTLY PUSHING SOUTH INTO
KENTUCKY...WITH PWAT VALUES EXPECTED TO BE IN THE 2.0 AND ABOVE RANGE
FOR A 6 HOUR TIME PERIOD BOTH THIS MORNING AND FRIDAY MORNING. WITH
SOME OF THESE SHOWERS AND THUNDERSTORMS...RAIN RATES OF 2 TO 3 INCHES
AN HOUR ARE VERY POSSIBLE. LOCALIZED FLASH FLOODING WILL BE A THREAT
THEREFORE...ESPECIALLY IN AREAS THAT HAVE MULTIPLE STORMS PASS OVER
THEIR LOCATION IN THE NEXT 48 HOURS. LATEST NAM IS ALSO TARGETING
ANOTHER SWATH OF HEAVIER PRECIP MOVING INTO THE REGION SATURDAY
MORNING...AFTER THE EXPIRATION OF THE FFA. THIS IS SUBJECT TO CHANGE
WITH LATER MODEL RUNS...SO FIGURED IT WOULD BE EASIER TO EXTEND THE
FFA IN THE FUTURE IF NEEDED RATHER THAN HAVE TO CANCEL IT AND END UP
NEEDING TO REISSUE. THE LATEST SPENES PRODUCT FROM THE SATELLITE
BRANCH ALSO PINPOINTED A LARGE SECTION OF OUR SOUTHWESTERN CWA IN
THEIR AREA OF CONCERN FOR EXCESSIVE RAINFALL THIS MORNING. THIS JUST
FURTHER SOLIDIFIED THE DECISION TO GO AHEAD AND ISSUE THE FFA FOR THE
REGION.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 413 AM EDT THU AUG 8 2013
THE COLD FRONT THAT HAS REMAINED NEARLY STATIONARY JUST NORTH OF THE
OHIO RIVER VALLEY YESTERDAY WILL FINALLY BEGIN ITS PUSH SEWARD
ACROSS KY DURING THE DAY TODAY...REACHING THE SE PORTION OF THE
STATE BY EVENING. AS WAS THE CASE WITH THIS SYSTEM YESTERDAY...HIGH
HUMIDITY VALUES IN ADDITION TO THE ISENTROPIC LIFT PROVIDED BY THIS
FRONT WILL WORK TO SPAWN CONVECTION...ESPECIALLY WITH THE ADDITION
OF DAYTIME HEATING AND GREATER INSTABILITY. EXPECT A LARGE AREA OF
SHOWERS AND POTENTIAL THUNDERSTORMS TO DEVELOP JUST AHEAD OF THE
FRONT AND ENCOMPASS MUCH OF THE CWA...THEN SHIFT SLIGHTLY EASTWARD
AS THE FRONT NEARS INTO THE REGION. CURRENT RADAR TRENDS ARE ALREADY
SUPPORTING THIS IDEA...WITH SCATTERED SHOWERS CONTINUING TO DEVELOP
ACROSS THE WESTERN HALF OF THE CWA. WHILE MODELS REMAIN FAIRLY
CONSISTENT THAT PRECIP WILL OVERSPREAD THE AREA...THERE IS STILL
SOME SUBTLE DIFFERENCES IN RESOLUTION AS TO WHERE THE HEAVIEST
PRECIP WILL OCCUR. BASED ON THE LATEST HRRR AND NAM12...EXPECT BEST
PRECIP DEVELOPMENT ACROSS THE SOUTHERN EXTENT OF THE CWA IN THE
MORNING...SPREADING TO THE NORTH BY THE AFTERNOON.
BY 0Z FRIDAY...FRONT WILL ONCE AGAIN BECOME STATIONARY...THIS TIME
PARKING ITSELF ACROSS EASTERN KY. WITH SUCH HUMID AND UNSTABLE
CONDITIONS IN PLACE...WILL CONTINUE WITH ONGOING FORECAST OF SOME
SCT CONVECTIVE POSSIBILITY THROUGHOUT THE NIGHT...SINCE ANY STORM
ONGOING IN THE AFTERNOON WILL TAKE SOME TIME TO DIE OFF...AND THERE
IS ALWAYS THE POSSIBILITY THAT ANY LITTLE AREA OF LIFT COULD
INITIATE SOME MORE SHOWERS. LUCKILY...WITH LOSS OF DAYTIME
HEATING...BEST INSTABILITY AND THUNDERSTORM POTENTIAL WILL LESSON.
HIGH DEW POINTS WILL ALSO LEAD TO LITTLE VARIATION FOR
TEMPERATURES...WITH LOWS ONLY DROPPING TO AROUND 70.
FRIDAY WILL BRING ABOUT SIMILAR CONDITIONS TO TODAY...WITH THE
STATIONARY FRONT LIFTING SLIGHTLY JUST TO THE NORTH OF THE CWA. AN
UPPER LEVEL SHORTWAVE MOVING THROUGH EASTERN KY BY FRIDAY MORNING
WILL BE ENOUGH TO KICK START SHOWER AND THUNDERSTORM DEVELOPMENT
ACROSS THE REGION. WHILE PRECIPITABLE WATER VALUES WERE NEARING 2
INCHES FOR TODAY/S FORECAST...ACCORDING TO LATEST NAM12
SOUNDINGS...FRIDAY/S SOUNDINGS ARE POINTING AT WELL OVER 2.10 INCHES
IN MANY LOCATIONS WITHIN A 6 HOUR PERIOD. IF A STRONG SHOWER OR
THUNDERSTORM DEVELOPS AND MOVES OVER A PARTICULAR SITE...FLASH
FLOODING IS A DEFINITE THREAT...ESPECIALLY IF THEY ARE IMPACTED BY
TODAY/S CONVECTIVE ACTIVITY. MOST OF THIS MOISTURE IS EXPECTED TO
FALL DURING THE MORNING AND EARLY AFTERNOON HOURS...WITH PWAT VALUES
SLIGHTLY LESS...IN THE 1.5-2.0 RANGE IN THE AFTERNOON HOURS.
TEMPERATURES SHOULD REMAIN FAIRLY SIMILAR TO TODAY WITH LITTLE
CHANGE IN THE OVERALL PATTERN.
SINCE A LOT OF THE EXPECTED PRECIP IS BASED ON MESOSCALE
DEVELOPMENT...DISCUSSED THE IDEA OF ISSUING A FFA FOR THE AREA...BUT
ULTIMATELY DECIDED TO HOLD OFF FOR RIGHT NOW. FUTURE SHIFTS MAY
DECIDE TO PULL THE TRIGGER BASED ON HOW WIDESPREAD AND HEAVY THE
DAY/S CONVECTIVE DEVELOPMENT PROVES TO BE.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 413 AM EDT THU AUG 8 2013
THE MODELS CONTINUE TO BE IN GOOD AGREEMENT ON THE GENERAL UPPER AIR
PATTERN THAT WILL GUIDE OUR WEATHER THROUGH THE EXTENDED PORTION OF
THE FORECAST. THIS CONSISTS PRIMARILY OF A DEEP AND PERSISTENT
TROUGH OVER SOUTHEAST CANADA AND A FLAT RIDGE OVER THE SOUTHERN TIER
OF THIS NATION. BETWEEN THESE...FAIRLY FAST MID LEVEL FLOW WILL
CARRY SHORT WAVE ENERGY FROM THE WEST COAST THROUGH THE OHIO VALLEY
BEFORE EXITING OFF THE EASTERN SEABOARD. THIS FLOW WILL BE FAIRLY
ZONAL OVER KENTUCKY THROUGH THE WEEKEND BEFORE A WESTERN RESURGENCE
IN THE CANADIAN TROUGH INDUCES A DIP SOUTH THROUGH THE GREAT LAKES
AND INTO THE NORTHERN OHIO VALLEY. THIS WILL RESULT IN MORE OF A
NORTHWEST FLOW PATTERN FOLLOWING THE WEEKEND INTO THE MIDDLE OF NEXT
WEEK. THE GFS AND ECMWF DIFFER MOST DURING THE LATTER PORTION OF THE
FORECAST AS THE ECMWF RUNS A BIT FASTER AND FURTHER EAST WITH THE
CANADIAN LOW/S REDEVELOPMENT INTO THE DAY MONDAY. THE GFS TAKES THE
CORE OF THIS LOW FURTHER SOUTH ON TUESDAY...DIPPING INTO THE
STATES...BEFORE LIFTING IT JUST NORTH OF EAST. DURING THIS TIME OF
LARGER GFS/ECMWF DISCREPANCY THE GEM SEEMS TO BE SIDING WITH THE
ECMWF SO THE MORE EXTREME GFS SOLUTION FOR MONDAY TO WEDNESDAY WILL
BE DISCOUNTED. ALSO...ITS RUN TO RUN CONSISTENCY HAS BEEN POOR...NOT
THAT THE ECMWF HAS BEEN ALL THAT MUCH BETTER/JUST NOT SO OUT THERE
AT TIMES...FOR THE LATTER PART OF THE EXTENDED. ACCORDINGLY...WILL
FAVOR THE BLENDED RESULTS THROUGH THE WEEKEND BEFORE LEANING MORE
TOWARD THE ECMWF INTO THE MIDDLE OF NEXT WEEK.
SENSIBLE WEATHER WILL FEATURE A CONTINUATION OF OUR WET PATTERN THAT
IS PRIMED FOR BOUTS OF HEAVY RAIN. THE SFC BOUNDARY WILL REMAIN
STALLED THROUGH THE REGION INTO THE WEEKEND WITH EACH SFC WAVE
RIPPLING PAST...POTENTIALLY SENDING THE BOUNDARY AND ITS HEAVIEST
RAIN OUR WAY. HIGH PW AIR AND DAYTIME INSTABILITY WILL PROVIDE THE
FUEL FOR THIS MCS ACTIVITY. THEREFORE...POPS WILL REMAIN HIGH INTO
THE WEEKEND WITH MAX TEMPERATURES CAPPED BELOW NORMAL DUE TO CLOUDS
AND CONVECTION. FOR THE START OF NEXT WEEK...IT LOOKS LIKE THE
AMPLIFYING TROUGH ALOFT WILL BE ENOUGH TO EVENTUALLY PUSH THE FRONT
SOUTH OF THE AREA AND ALLOW DRIER AIR TO FLOW INTO THE STATE. THE
FAVORED 12Z ECMWF DOES TAKE THE DEEPER MOISTURE SOUTH LATER MONDAY
WHILE THE GFS WAITS UNTIL A SECONDARY FRONT PUSHES THROUGH ON
TUESDAY NIGHT. WILL CONTINUE SMALL POPS INTO TUESDAY FOR THIS
TRANSITION...BUT NOT AS HIGH AS THE GFS WOULD IMPLY. HOPEFULLY
WEDNESDAY WILL TURN OUT AS PLEASANT AS THE MODEL CONSENSUS SUGGESTS
WITH A RETURN OF DECENT SUNSHINE AND MUCH DRIER AIR. WE WILL SEE...
BUT AT LEAST THIS SEEMS TO BE A BUILDING AND STABILIZING ASPECT OF
THE FORECAST FROM THE LATEST MEDIUM RANGE MODELS.
THE CR GRID LOAD CAME IN NICELY FOR THIS UNSETTLED FORECAST THROUGH
THE WEEKEND. DID TWEAK POPS TO ADD MORE OF A DIURNAL CYCLE AND ALSO
TOWARD THE LATEST SPECIFICS FROM THE 12Z ECMWF FOR MONDAY ON INTO
WEDNESDAY. ONLY MADE MINOR TERRAIN BASED ADJUSTMENTS FOR TEMPS
THROUGHOUT THE BULK OF THIS EXTENDED PERIOD GIVEN THE HIGH MOISTURE
CONTENT...AT LEAST THROUGH TUESDAY MORNING.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 750 AM EDT THU AUG 8 2013
FOR THE MOST PART...EXPECT VFR CONDITIONS AT TAF SITES UNLESS
INFLUENCED BY THE PASSAGE OF A RAIN SHOWER. BEST CONVECTIVE CHANCES
WILL DEVELOP IN THE MORNING...WITH POSSIBLE MVFR CIGS EXPECTED AT
ONSET. THE EXACT SET UP OF THESE STORMS IN RELATION TO HOW THEY
WILL AFFECT THE TAF SITES IS STILL SOMEWHAT UNCERTAIN. IF A HEAVY
SHOWER OR THUNDERSTORM DOES IMPACT A SITE DURING THE DAY...VIS COULD
TEMPORARILY BE REDUCED BELOW MVFR. SHOWERS AND THUNDERSTORMS WILL DIE
DOWN LATER THIS EVENING WITH LOSS OF DAYTIME HEATING...THOUGH SOME
SCT CONVECTION IS STILL POSSIBLE THROUGH THE REMAINDER OF THE TAF
PERIOD. MUCH LIKE THIS PAST NIGHT...EXPECT OVERALL CONDITIONS TO
IMPROVE TO VFR WITH LOWER CONDITIONS EXPECTED IF A SHOWER OR
LINGERING THUNDERSTORM PASSES OVER A TAF SITE. AS FAR AS FOG...SOME
TEMPORARY BR IS BEING REPORTED AT KJKL IN CONJUNCTION WITH THE
EARLIER RAIN INTERACTING WITH THE WARM HUMID CONDITIONS. LIKEWISE...
FOR TONIGHT WITH EXTENSIVE CLOUD COVER EXPECTED ACROSS MUCH OF THE
REGION...ANY WIDESPREAD FOG DEVELOPMENT IS UNLIKELY...ESPECIALLY TO A
DEGREE THAT IT WILL SIGNIFICANTLY AFFECT THE TAF SITES. WINDS THROUGH
THE PERIOD WILL BE LIGHT AND VARIABLE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR KYZ044-050>052-
058>060-068-069-079-080-083>088-104-106>120.
&&
$$
UPDATE...HAL
SHORT TERM...JMW
LONG TERM...GREIF
AVIATION...JMW/GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
750 AM EDT THU AUG 8 2013
.UPDATE...
ISSUED AT 628 AM EDT THU AUG 8 2013
AFTER TALKING WITH NEIGHBORING OFFICES LMK AND RLX...AS WELL AS
SEEING THE LATEST HPC QPF GUIDANCE...MADE THE DECISION TO ISSUE AN
FFA FOR THE REGION THROUGH FRIDAY EVENING. SCT CONVECTION CONTINUES
TO DEVELOP ALONG THE BOUNDARY CURRENTLY PUSHING SOUTH INTO
KENTUCKY...WITH PWAT VALUES EXPECTED TO BE IN THE 2.0 AND ABOVE RANGE
FOR A 6 HOUR TIME PERIOD BOTH THIS MORNING AND FRIDAY MORNING. WITH
SOME OF THESE SHOWERS AND THUNDERSTORMS...RAIN RATES OF 2 TO 3 INCHES
AN HOUR ARE VERY POSSIBLE. LOCALIZED FLASH FLOODING WILL BE A THREAT
THEREFORE...ESPECIALLY IN AREAS THAT HAVE MULTIPLE STORMS PASS OVER
THEIR LOCATION IN THE NEXT 48 HOURS. LATEST NAM IS ALSO TARGETING
ANOTHER SWATH OF HEAVIER PRECIP MOVING INTO THE REGION SATURDAY
MORNING...AFTER THE EXPIRATION OF THE FFA. THIS IS SUBJECT TO CHANGE
WITH LATER MODEL RUNS...SO FIGURED IT WOULD BE EASIER TO EXTEND THE
FFA IN THE FUTURE IF NEEDED RATHER THAN HAVE TO CANCEL IT AND END UP
NEEDING TO REISSUE. THE LATEST SPENES PRODUCT FROM THE SATELLITE
BRANCH ALSO PINPOINTED A LARGE SECTION OF OUR SOUTHWESTERN CWA IN
THEIR AREA OF CONCERN FOR EXCESSIVE RAINFALL THIS MORNING. THIS JUST
FURTHER SOLIDIFIED THE DECISION TO GO AHEAD AND ISSUE THE FFA FOR THE
REGION.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 413 AM EDT THU AUG 8 2013
THE COLD FRONT THAT HAS REMAINED NEARLY STATIONARY JUST NORTH OF THE
OHIO RIVER VALLEY YESTERDAY WILL FINALLY BEGIN ITS PUSH SEWARD
ACROSS KY DURING THE DAY TODAY...REACHING THE SE PORTION OF THE
STATE BY EVENING. AS WAS THE CASE WITH THIS SYSTEM YESTERDAY...HIGH
HUMIDITY VALUES IN ADDITION TO THE ISENTROPIC LIFT PROVIDED BY THIS
FRONT WILL WORK TO SPAWN CONVECTION...ESPECIALLY WITH THE ADDITION
OF DAYTIME HEATING AND GREATER INSTABILITY. EXPECT A LARGE AREA OF
SHOWERS AND POTENTIAL THUNDERSTORMS TO DEVELOP JUST AHEAD OF THE
FRONT AND ENCOMPASS MUCH OF THE CWA...THEN SHIFT SLIGHTLY EASTWARD
AS THE FRONT NEARS INTO THE REGION. CURRENT RADAR TRENDS ARE ALREADY
SUPPORTING THIS IDEA...WITH SCATTERED SHOWERS CONTINUING TO DEVELOP
ACROSS THE WESTERN HALF OF THE CWA. WHILE MODELS REMAIN FAIRLY
CONSISTENT THAT PRECIP WILL OVERSPREAD THE AREA...THERE IS STILL
SOME SUBTLE DIFFERENCES IN RESOLUTION AS TO WHERE THE HEAVIEST
PRECIP WILL OCCUR. BASED ON THE LATEST HRRR AND NAM12...EXPECT BEST
PRECIP DEVELOPMENT ACROSS THE SOUTHERN EXTENT OF THE CWA IN THE
MORNING...SPREADING TO THE NORTH BY THE AFTERNOON.
BY 0Z FRIDAY...FRONT WILL ONCE AGAIN BECOME STATIONARY...THIS TIME
PARKING ITSELF ACROSS EASTERN KY. WITH SUCH HUMID AND UNSTABLE
CONDITIONS IN PLACE...WILL CONTINUE WITH ONGOING FORECAST OF SOME
SCT CONVECTIVE POSSIBILITY THROUGHOUT THE NIGHT...SINCE ANY STORM
ONGOING IN THE AFTERNOON WILL TAKE SOME TIME TO DIE OFF...AND THERE
IS ALWAYS THE POSSIBILITY THAT ANY LITTLE AREA OF LIFT COULD
INITIATE SOME MORE SHOWERS. LUCKILY...WITH LOSS OF DAYTIME
HEATING...BEST INSTABILITY AND THUNDERSTORM POTENTIAL WILL LESSON.
HIGH DEWPOINTS WILL ALSO LEAD TO LITTLE VARIATION FOR
TEMPERATURES...WITH LOWS ONLY DROPPING TO AROUND 70.
FRIDAY WILL BRING ABOUT SIMILAR CONDITIONS TO TODAY...WITH THE
STATIONARY FRONT LIFTING SLIGHTLY JUST TO THE NORTH OF THE CWA. AN
UPPER LEVEL SHORTWAVE MOVING THROUGH EASTERN KY BY FRIDAY MORNING
WILL BE ENOUGH TO KICK START SHOWER AND THUNDERSTORM DEVELOPMENT
ACROSS THE REGION. WHILE PRECIPITABLE WATER VALUES WERE NEARING 2
INCHES FOR TODAY/S FORECAST...ACCORDING TO LATEST NAM12
SOUNDINGS...FRIDAY/S SOUNDINGS ARE POINTING AT WELL OVER 2.10 INCHES
IN MANY LOCATIONS WITHIN A 6 HOUR PERIOD. IF A STRONG SHOWER OR
THUNDERSTORM DEVELOPS AND MOVES OVER A PARTICULAR SITE...FLASH
FLOODING IS A DEFINITE THREAT...ESPECIALLY IF THEY ARE IMPACTED BY
TODAY/S CONVECTIVE ACTIVITY. MOST OF THIS MOISTURE IS EXPECTED TO
FALL DURING THE MORNING AND EARLY AFTERNOON HOURS...WITH PWAT VALUES
SLIGHTLY LESS...IN THE 1.5-2.0 RANGE IN THE AFTERNOON HOURS.
TEMPERATURES SHOULD REMAIN FAIRLY SIMILAR TO TODAY WITH LITTLE
CHANGE IN THE OVERALL PATTERN.
SINCE A LOT OF THE EXPECTED PRECIP IS BASED ON MESOSCALE
DEVELOPMENT...DISCUSSED THE IDEA OF ISSUING A FFA FOR THE AREA...BUT
ULTIMATELY DECIDED TO HOLD OFF FOR RIGHT NOW. FUTURE SHIFTS MAY
DECIDE TO PULL THE TRIGGER BASED ON HOW WIDESPREAD AND HEAVY THE
DAY/S CONVECTIVE DEVELOPMENT PROVES TO BE.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 413 AM EDT THU AUG 8 2013
THE MODELS CONTINUE TO BE IN GOOD AGREEMENT ON THE GENERAL UPPER AIR
PATTERN THAT WILL GUIDE OUR WEATHER THROUGH THE EXTENDED PORTION OF
THE FORECAST. THIS CONSISTS PRIMARILY OF A DEEP AND PERSISTENT
TROUGH OVER SOUTHEAST CANADA AND A FLAT RIDGE OVER THE SOUTHERN TIER
OF THIS NATION. BETWEEN THESE...FAIRLY FAST MID LEVEL FLOW WILL
CARRY SHORT WAVE ENERGY FROM THE WEST COAST THROUGH THE OHIO VALLEY
BEFORE EXITING OFF THE EASTERN SEABOARD. THIS FLOW WILL BE FAIRLY
ZONAL OVER KENTUCKY THROUGH THE WEEKEND BEFORE A WESTERN RESURGENCE
IN THE CANADIAN TROUGH INDUCES A DIP SOUTH THROUGH THE GREAT LAKES
AND INTO THE NORTHERN OHIO VALLEY. THIS WILL RESULT IN MORE OF A
NORTHWEST FLOW PATTERN FOLLOWING THE WEEKEND INTO THE MIDDLE OF NEXT
WEEK. THE GFS AND ECMWF DIFFER MOST DURING THE LATTER PORTION OF THE
FORECAST AS THE ECMWF RUNS A BIT FASTER AND FURTHER EAST WITH THE
CANADIAN LOW/S REDEVELOPMENT INTO THE DAY MONDAY. THE GFS TAKES THE
CORE OF THIS LOW FURTHER SOUTH ON TUESDAY...DIPPING INTO THE
STATES...BEFORE LIFTING IT JUST NORTH OF EAST. DURING THIS TIME OF
LARGER GFS/ECMWF DISCREPANCY THE GEM SEEMS TO BE SIDING WITH THE
ECMWF SO THE MORE EXTREME GFS SOLUTION FOR MONDAY TO WEDNESDAY WILL
BE DISCOUNTED. ALSO...ITS RUN TO RUN CONSISTENCY HAS BEEN POOR...NOT
THAT THE ECMWF HAS BEEN ALL THAT MUCH BETTER/JUST NOT SO OUT THERE
AT TIMES...FOR THE LATTER PART OF THE EXTENDED. ACCORDINGLY...WILL
FAVOR THE BLENDED RESULTS THROUGH THE WEEKEND BEFORE LEANING MORE
TOWARD THE ECMWF INTO THE MIDDLE OF NEXT WEEK.
SENSIBLE WEATHER WILL FEATURE A CONTINUATION OF OUR WET PATTERN THAT
IS PRIMED FOR BOUTS OF HEAVY RAIN. THE SFC BOUNDARY WILL REMAIN
STALLED THROUGH THE REGION INTO THE WEEKEND WITH EACH SFC WAVE
RIPPLING PAST...POTENTIALLY SENDING THE BOUNDARY AND ITS HEAVIEST
RAIN OUR WAY. HIGH PW AIR AND DAYTIME INSTABILITY WILL PROVIDE THE
FUEL FOR THIS MCS ACTIVITY. THEREFORE...POPS WILL REMAIN HIGH INTO
THE WEEKEND WITH MAX TEMPERATURES CAPPED BELOW NORMAL DUE TO CLOUDS
AND CONVECTION. FOR THE START OF NEXT WEEK...IT LOOKS LIKE THE
AMPLIFYING TROUGH ALOFT WILL BE ENOUGH TO EVENTUALLY PUSH THE FRONT
SOUTH OF THE AREA AND ALLOW DRIER AIR TO FLOW INTO THE STATE. THE
FAVORED 12Z ECMWF DOES TAKE THE DEEPER MOISTURE SOUTH LATER MONDAY
WHILE THE GFS WAITS UNTIL A SECONDARY FRONT PUSHES THROUGH ON
TUESDAY NIGHT. WILL CONTINUE SMALL POPS INTO TUESDAY FOR THIS
TRANSITION...BUT NOT AS HIGH AS THE GFS WOULD IMPLY. HOPEFULLY
WEDNESDAY WILL TURN OUT AS PLEASANT AS THE MODEL CONSENSUS SUGGESTS
WITH A RETURN OF DECENT SUNSHINE AND MUCH DRIER AIR. WE WILL SEE...
BUT AT LEAST THIS SEEMS TO BE A BUILDING AND STABILIZING ASPECT OF
THE FORECAST FROM THE LATEST MEDIUM RANGE MODELS.
THE CR GRID LOAD CAME IN NICELY FOR THIS UNSETTLED FORECAST THROUGH
THE WEEKEND. DID TWEAK POPS TO ADD MORE OF A DIURNAL CYCLE AND ALSO
TOWARD THE LATEST SPECIFICS FROM THE 12Z ECMWF FOR MONDAY ON INTO
WEDNESDAY. ONLY MADE MINOR TERRAIN BASED ADJUSTMENTS FOR TEMPS
THROUGHOUT THE BULK OF THIS EXTENDED PERIOD GIVEN THE HIGH MOISTURE
CONTENT...AT LEAST THROUGH TUESDAY MORNING.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 750 AM EDT THU AUG 8 2013
FOR THE MOST PART...EXPECT VFR CONDITIONS AT TAF SITES UNLESS
INFLUENCED BY THE PASSAGE OF A RAIN SHOWER. BEST CONVECTIVE CHANCES
WILL DEVELOP IN THE MORNING...WITH POSSIBLE MVFR CIGS EXPECTED AT
ONSET. THE EXACT SET UP OF THESE STORMS IN RELATION TO HOW THEY
WILL AFFECT THE TAF SITES IS STILL SOMEWHAT UNCERTAIN. IF A HEAVY
SHOWER OR THUNDERSTORM DOES IMPACT A SITE DURING THE DAY...VIS COULD
TEMPORARILY BE REDUCED BELOW MVFR. SHOWERS AND THUNDERSTORMS WILL DIE
DOWN LATER THIS EVENING WITH LOSS OF DAYTIME HEATING...THOUGH SOME
SCT CONVECTION IS STILL POSSIBLE THROUGH THE REMAINDER OF THE TAF
PERIOD. MUCH LIKE THIS PAST NIGHT...EXPECT OVERALL CONDITIONS TO
IMPROVE TO VFR WITH LOWER CONDITIONS EXPECTED IF A SHOWER OR
LINGERING THUNDERSTORM PASSES OVER A TAF SITE. AS FAR AS FOG...SOME
TEMPORARY BR IS BEING REPORTED AT KJKL IN CONJUNCTION WITH THE
EARLIER RAIN INTERACTING WITH THE WARM HUMID CONDITIONS. LIKEWISE...
FOR TONIGHT WITH EXTENSIVE CLOUD COVER EXPECTED ACROSS MUCH OF THE
REGION...ANY WIDESPREAD FOG DEVELOPMENT IS UNLIKELY...ESPECIALLY TO A
DEGREE THAT IT WILL SIGNIFICANTLY AFFECT THE TAF SITES. WINDS THROUGH
THE PERIOD WILL BE LIGHT AND VARIABLE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR KYZ044-050>052-
058>060-068-069-079-080-083>088-104-106>120.
&&
$$
UPDATE...JMW
SHORT TERM...JMW
LONG TERM...GREIF
AVIATION...JMW/GREIF
AREA FORECAST DISCUSSION
NWS JACKSON KY
628 AM EDT THU AUG 8 2013
.UPDATE...
ISSUED AT 628 AM EDT THU AUG 8 2013
AFTER TALKING WITH NEIGHBORING OFFICES LMK AND RLX...AS WELL AS
SEEING THE LATEST HPC QPF GUIDANCE...MADE THE DECISION TO ISSUE AN
FFA FOR THE REGION THROUGH FRIDAY EVENING. SCT CONVECTION CONTINUES
TO DEVELOP ALONG THE BOUNDARY CURRENTLY PUSHING SOUTH INTO
KENTUCKY...WITH PWAT VALUES EXPECTED TO BE IN THE 2.0 AND ABOVE RANGE
FOR A 6 HOUR TIME PERIOD BOTH THIS MORNING AND FRIDAY MORNING. WITH
SOME OF THESE SHOWERS AND THUNDERSTORMS...RAIN RATES OF 2 TO 3 INCHES
AN HOUR ARE VERY POSSIBLE. LOCALIZED FLASH FLOODING WILL BE A THREAT
THEREFORE...ESPECIALLY IN AREAS THAT HAVE MULTIPLE STORMS PASS OVER
THEIR LOCATION IN THE NEXT 48 HOURS. LATEST NAM IS ALSO TARGETING
ANOTHER SWATH OF HEAVIER PRECIP MOVING INTO THE REGION SATURDAY
MORNING...AFTER THE EXPIRATION OF THE FFA. THIS IS SUBJECT TO CHANGE
WITH LATER MODEL RUNS...SO FIGURED IT WOULD BE EASIER TO EXTEND THE
FFA IN THE FUTURE IF NEEDED RATHER THAN HAVE TO CANCEL IT AND END UP
NEEDING TO REISSUE. SPENES ALSO PINPOINTED A LARGE SECTION OF OUR
SOUTHWESTERN CWA IN THEIR AREA OF CONCERN FOR EXCESSIVE RAINFALL THIS
MORNING. THIS JUST FURTHER SOLIDIFIED THE DECISION TO GO AHEAD AND
ISSUE THE FFA FOR THE REGION.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 413 AM EDT THU AUG 8 2013
THE COLD FRONT THAT HAS REMAINED NEARLY STATIONARY JUST NORTH OF THE
OHIO RIVER VALLEY YESTERDAY WILL FINALLY BEGIN ITS PUSH SEWARD
ACROSS KY DURING THE DAY TODAY...REACHING THE SE PORTION OF THE
STATE BY EVENING. AS WAS THE CASE WITH THIS SYSTEM YESTERDAY...HIGH
HUMIDITY VALUES IN ADDITION TO THE ISENTROPIC LIFT PROVIDED BY THIS
FRONT WILL WORK TO SPAWN CONVECTION...ESPECIALLY WITH THE ADDITION
OF DAYTIME HEATING AND GREATER INSTABILITY. EXPECT A LARGE AREA OF
SHOWERS AND POTENTIAL THUNDERSTORMS TO DEVELOP JUST AHEAD OF THE
FRONT AND ENCOMPASS MUCH OF THE CWA...THEN SHIFT SLIGHTLY EASTWARD
AS THE FRONT NEARS INTO THE REGION. CURRENT RADAR TRENDS ARE ALREADY
SUPPORTING THIS IDEA...WITH SCATTERED SHOWERS CONTINUING TO DEVELOP
ACROSS THE WESTERN HALF OF THE CWA. WHILE MODELS REMAIN FAIRLY
CONSISTENT THAT PRECIP WILL OVERSPREAD THE AREA...THERE IS STILL
SOME SUBTLE DIFFERENCES IN RESOLUTION AS TO WHERE THE HEAVIEST
PRECIP WILL OCCUR. BASED ON THE LATEST HRRR AND NAM12...EXPECT BEST
PRECIP DEVELOPMENT ACROSS THE SOUTHERN EXTENT OF THE CWA IN THE
MORNING...SPREADING TO THE NORTH BY THE AFTERNOON.
BY 0Z FRIDAY...FRONT WILL ONCE AGAIN BECOME STATIONARY...THIS TIME
PARKING ITSELF ACROSS EASTERN KY. WITH SUCH HUMID AND UNSTABLE
CONDITIONS IN PLACE...WILL CONTINUE WITH ONGOING FORECAST OF SOME
SCT CONVECTIVE POSSIBILITY THROUGHOUT THE NIGHT...SINCE ANY STORM
ONGOING IN THE AFTERNOON WILL TAKE SOME TIME TO DIE OFF...AND THERE
IS ALWAYS THE POSSIBILITY THAT ANY LITTLE AREA OF LIFT COULD
INITIATE SOME MORE SHOWERS. LUCKILY...WITH LOSS OF DAYTIME
HEATING...BEST INSTABILITY AND THUNDERSTORM POTENTIAL WILL LESSON.
HIGH DEWPOINTS WILL ALSO LEAD TO LITTLE VARIATION FOR
TEMPERATURES...WITH LOWS ONLY DROPPING TO AROUND 70.
FRIDAY WILL BRING ABOUT SIMILAR CONDITIONS TO TODAY...WITH THE
STATIONARY FRONT LIFTING SLIGHTLY JUST TO THE NORTH OF THE CWA. AN
UPPER LEVEL SHORTWAVE MOVING THROUGH EASTERN KY BY FRIDAY MORNING
WILL BE ENOUGH TO KICK START SHOWER AND THUNDERSTORM DEVELOPMENT
ACROSS THE REGION. WHILE PRECIPITABLE WATER VALUES WERE NEARING 2
INCHES FOR TODAY/S FORECAST...ACCORDING TO LATEST NAM12
SOUNDINGS...FRIDAY/S SOUNDINGS ARE POINTING AT WELL OVER 2.10 INCHES
IN MANY LOCATIONS WITHIN A 6 HOUR PERIOD. IF A STRONG SHOWER OR
THUNDERSTORM DEVELOPS AND MOVES OVER A PARTICULAR SITE...FLASH
FLOODING IS A DEFINITE THREAT...ESPECIALLY IF THEY ARE IMPACTED BY
TODAY/S CONVECTIVE ACTIVITY. MOST OF THIS MOISTURE IS EXPECTED TO
FALL DURING THE MORNING AND EARLY AFTERNOON HOURS...WITH PWAT VALUES
SLIGHTLY LESS...IN THE 1.5-2.0 RANGE IN THE AFTERNOON HOURS.
TEMPERATURES SHOULD REMAIN FAIRLY SIMILAR TO TODAY WITH LITTLE
CHANGE IN THE OVERALL PATTERN.
SINCE A LOT OF THE EXPECTED PRECIP IS BASED ON MESOSCALE
DEVELOPMENT...DISCUSSED THE IDEA OF ISSUING A FFA FOR THE AREA...BUT
ULTIMATELY DECIDED TO HOLD OFF FOR RIGHT NOW. FUTURE SHIFTS MAY
DECIDE TO PULL THE TRIGGER BASED ON HOW WIDESPREAD AND HEAVY THE
DAY/S CONVECTIVE DEVELOPMENT PROVES TO BE.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 413 AM EDT THU AUG 8 2013
THE MODELS CONTINUE TO BE IN GOOD AGREEMENT ON THE GENERAL UPPER AIR
PATTERN THAT WILL GUIDE OUR WEATHER THROUGH THE EXTENDED PORTION OF
THE FORECAST. THIS CONSISTS PRIMARILY OF A DEEP AND PERSISTENT
TROUGH OVER SOUTHEAST CANADA AND A FLAT RIDGE OVER THE SOUTHERN TIER
OF THIS NATION. BETWEEN THESE...FAIRLY FAST MID LEVEL FLOW WILL
CARRY SHORT WAVE ENERGY FROM THE WEST COAST THROUGH THE OHIO VALLEY
BEFORE EXITING OFF THE EASTERN SEABOARD. THIS FLOW WILL BE FAIRLY
ZONAL OVER KENTUCKY THROUGH THE WEEKEND BEFORE A WESTERN RESURGENCE
IN THE CANADIAN TROUGH INDUCES A DIP SOUTH THROUGH THE GREAT LAKES
AND INTO THE NORTHERN OHIO VALLEY. THIS WILL RESULT IN MORE OF A
NORTHWEST FLOW PATTERN FOLLOWING THE WEEKEND INTO THE MIDDLE OF NEXT
WEEK. THE GFS AND ECMWF DIFFER MOST DURING THE LATTER PORTION OF THE
FORECAST AS THE ECMWF RUNS A BIT FASTER AND FURTHER EAST WITH THE
CANADIAN LOW/S REDEVELOPMENT INTO THE DAY MONDAY. THE GFS TAKES THE
CORE OF THIS LOW FURTHER SOUTH ON TUESDAY...DIPPING INTO THE
STATES...BEFORE LIFTING IT JUST NORTH OF EAST. DURING THIS TIME OF
LARGER GFS/ECMWF DISCREPANCY THE GEM SEEMS TO BE SIDING WITH THE
ECMWF SO THE MORE EXTREME GFS SOLUTION FOR MONDAY TO WEDNESDAY WILL
BE DISCOUNTED. ALSO...ITS RUN TO RUN CONSISTENCY HAS BEEN POOR...NOT
THAT THE ECMWF HAS BEEN ALL THAT MUCH BETTER/JUST NOT SO OUT THERE
AT TIMES...FOR THE LATTER PART OF THE EXTENDED. ACCORDINGLY...WILL
FAVOR THE BLENDED RESULTS THROUGH THE WEEKEND BEFORE LEANING MORE
TOWARD THE ECMWF INTO THE MIDDLE OF NEXT WEEK.
SENSIBLE WEATHER WILL FEATURE A CONTINUATION OF OUR WET PATTERN THAT
IS PRIMED FOR BOUTS OF HEAVY RAIN. THE SFC BOUNDARY WILL REMAIN
STALLED THROUGH THE REGION INTO THE WEEKEND WITH EACH SFC WAVE
RIPPLING PAST...POTENTIALLY SENDING THE BOUNDARY AND ITS HEAVIEST
RAIN OUR WAY. HIGH PW AIR AND DAYTIME INSTABILITY WILL PROVIDE THE
FUEL FOR THIS MCS ACTIVITY. THEREFORE...POPS WILL REMAIN HIGH INTO
THE WEEKEND WITH MAX TEMPERATURES CAPPED BELOW NORMAL DUE TO CLOUDS
AND CONVECTION. FOR THE START OF NEXT WEEK...IT LOOKS LIKE THE
AMPLIFYING TROUGH ALOFT WILL BE ENOUGH TO EVENTUALLY PUSH THE FRONT
SOUTH OF THE AREA AND ALLOW DRIER AIR TO FLOW INTO THE STATE. THE
FAVORED 12Z ECMWF DOES TAKE THE DEEPER MOISTURE SOUTH LATER MONDAY
WHILE THE GFS WAITS UNTIL A SECONDARY FRONT PUSHES THROUGH ON
TUESDAY NIGHT. WILL CONTINUE SMALL POPS INTO TUESDAY FOR THIS
TRANSITION...BUT NOT AS HIGH AS THE GFS WOULD IMPLY. HOPEFULLY
WEDNESDAY WILL TURN OUT AS PLEASANT AS THE MODEL CONSENSUS SUGGESTS
WITH A RETURN OF DECENT SUNSHINE AND MUCH DRIER AIR. WE WILL SEE...
BUT AT LEAST THIS SEEMS TO BE A BUILDING AND STABILIZING ASPECT OF
THE FORECAST FROM THE LATEST MEDIUM RANGE MODELS.
THE CR GRID LOAD CAME IN NICELY FOR THIS UNSETTLED FORECAST THROUGH
THE WEEKEND. DID TWEAK POPS TO ADD MORE OF A DIURNAL CYCLE AND ALSO
TOWARD THE LATEST SPECIFICS FROM THE 12Z ECMWF FOR MONDAY ON INTO
WEDNESDAY. ONLY MADE MINOR TERRAIN BASED ADJUSTMENTS FOR TEMPS
THROUGHOUT THE BULK OF THIS EXTENDED PERIOD GIVEN THE HIGH MOISTURE
CONTENT...AT LEAST THROUGH TUESDAY MORNING.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 137 AM EDT THU AUG 8 2013
SIMILAR SITUATION TO LAST NIGHT...WITH SCT PRECIP ACROSS THE AREA AND
CLOUD HEIGHTS VARYING FROM POCKETS OF MVFR TO MID LEVEL VFR ACROSS
THE AREA. WHERE THE TAF SITES WILL CONTINUE TO FALL WITHIN THIS
PATTERN WILL BE THE MAIN CONCERN OVERNIGHT. FOR THE MOST
PART...EXPECT VFR CONDITIONS AT TAF SITES UNLESS INFLUENCED BY THE
PASSAGE OF A RAIN SHOWER. BEST CONVECTIVE CHANCES WILL DEVELOP IN THE
MORNING...WITH POSSIBLE MVFR CIGS EXPECTED WITH ONSET. THE EXACT SET
UP OF THESE STORMS IN RELATION TO HOW THEY WILL AFFECT THE TAF SITES
IS STILL SOMEWHAT UNCERTAIN. IF A HEAVY SHOWER OR THUNDERSTORM DOES
IMPACT A SITE DURING THE DAY...VIS COULD TEMPORARILY BE REDUCED BELOW
MVFR. SHOWERS AND THUNDERSTORMS WILL DIE DOWN TOMORROW EVENING WITH
LOSS OF DAYTIME HEATING...THOUGH SOME SCT CONVECTION IS STILL
POSSIBLE THROUGH THE REMAINDER OF THE TAF PERIOD. MUCH LIKE
TONIGHT...EXPECT OVERALL CONDITIONS TO IMPROVE TO VFR WITH SOME
POSSIBLE ADJUSTMENTS IF A SHOWER OR LINGERING THUNDERSTORM PASSES OVER
TAF SITE. AS FAR AS FOG OVERNIGHT...SOME TEMPORARY BR IS BEING
REPORTED AT KJKL IN CONJUNCTION WITH THE RAIN THAT JUST PASSED OVER
INTERACTING WITH THE WARM HUMID CONDITIONS. OTHERWISE...WITH CLOUD COVER
ACROSS MUCH OF THE REGION...ANY WIDESPREAD FOG DEVELOPMENT IS
UNLIKELY...ESPECIALLY TO A DEGREE THAT IT WILL AFFECT THE TAF SITES.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR KYZ044-050>052-
058>060-068-069-079-080-083>088-104-106>120.
&&
$$
UPDATE...JMW
SHORT TERM...JMW
LONG TERM...GREIF
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS JACKSON KY
413 AM EDT THU AUG 8 2013
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 413 AM EDT THU AUG 8 2013
THE COLD FRONT THAT HAS REMAINED NEARLY STATIONARY JUST NORTH OF THE
OHIO RIVER VALLEY YESTERDAY WILL FINALLY BEGIN ITS PUSH SEWARD
ACROSS KY DURING THE DAY TODAY...REACHING THE SE PORTION OF THE
STATE BY EVENING. AS WAS THE CASE WITH THIS SYSTEM YESTERDAY...HIGH
HUMIDITY VALUES IN ADDITION TO THE ISENTROPIC LIFT PROVIDED BY THIS
FRONT WILL WORK TO SPAWN CONVECTION...ESPECIALLY WITH THE ADDITION
OF DAYTIME HEATING AND GREATER INSTABILITY. EXPECT A LARGE AREA OF
SHOWERS AND POTENTIAL THUNDERSTORMS TO DEVELOP JUST AHEAD OF THE
FRONT AND ENCOMPASS MUCH OF THE CWA...THEN SHIFT SLIGHTLY EASTWARD
AS THE FRONT NEARS INTO THE REGION. CURRENT RADAR TRENDS ARE ALREADY
SUPPORTING THIS IDEA...WITH SCATTERED SHOWERS CONTINUING TO DEVELOP
ACROSS THE WESTERN HALF OF THE CWA. WHILE MODELS REMAIN FAIRLY
CONSISTENT THAT PRECIP WILL OVERSPREAD THE AREA...THERE IS STILL
SOME SUBTLE DIFFERENCES IN RESOLUTION AS TO WHERE THE HEAVIEST
PRECIP WILL OCCUR. BASED ON THE LATEST HRRR AND NAM12...EXPECT BEST
PRECIP DEVELOPMENT ACROSS THE SOUTHERN EXTENT OF THE CWA IN THE
MORNING...SPREADING TO THE NORTH BY THE AFTERNOON.
BY 0Z FRIDAY...FRONT WILL ONCE AGAIN BECOME STATIONARY...THIS TIME
PARKING ITSELF ACROSS EASTERN KY. WITH SUCH HUMID AND UNSTABLE
CONDITIONS IN PLACE...WILL CONTINUE WITH ONGOING FORECAST OF SOME
SCT CONVECTIVE POSSIBILITY THROUGHOUT THE NIGHT...SINCE ANY STORM
ONGOING IN THE AFTERNOON WILL TAKE SOME TIME TO DIE OFF...AND THERE
IS ALWAYS THE POSSIBILITY THAT ANY LITTLE AREA OF LIFT COULD
INITIATE SOME MORE SHOWERS. LUCKILY...WITH LOSS OF DAYTIME
HEATING...BEST INSTABILITY AND THUNDERSTORM POTENTIAL WILL LESSON.
HIGH DEWPOINTS WILL ALSO LEAD TO LITTLE VARIATION FOR
TEMPERATURES...WITH LOWS ONLY DROPPING TO AROUND 70.
FRIDAY WILL BRING ABOUT SIMILAR CONDITIONS TO TODAY...WITH THE
STATIONARY FRONT LIFTING SLIGHTLY JUST TO THE NORTH OF THE CWA. AN
UPPER LEVEL SHORTWAVE MOVING THROUGH EASTERN KY BY FRIDAY MORNING
WILL BE ENOUGH TO KICK START SHOWER AND THUNDERSTORM DEVELOPMENT
ACROSS THE REGION. WHILE PRECIPITABLE WATER VALUES WERE NEARING 2
INCHES FOR TODAY/S FORECAST...ACCORDING TO LATEST NAM12
SOUNDINGS...FRIDAY/S SOUNDINGS ARE POINTING AT WELL OVER 2.10 INCHES
IN MANY LOCATIONS WITHIN A 6 HOUR PERIOD. IF A STRONG SHOWER OR
THUNDERSTORM DEVELOPS AND MOVES OVER A PARTICULAR SITE...FLASH
FLOODING IS A DEFINITE THREAT...ESPECIALLY IF THEY ARE IMPACTED BY
TODAY/S CONVECTIVE ACTIVITY. MOST OF THIS MOISTURE IS EXPECTED TO
FALL DURING THE MORNING AND EARLY AFTERNOON HOURS...WITH PWAT VALUES
SLIGHTLY LESS...IN THE 1.5-2.0 RANGE IN THE AFTERNOON HOURS.
TEMPERATURES SHOULD REMAIN FAIRLY SIMILAR TO TODAY WITH LITTLE
CHANGE IN THE OVERALL PATTERN.
SINCE A LOT OF THE EXPECTED PRECIP IS BASED ON MESOSCALE
DEVELOPMENT...DISCUSSED THE IDEA OF ISSUING A FFA FOR THE AREA...BUT
ULTIMATELY DECIDED TO HOLD OFF FOR RIGHT NOW. FUTURE SHIFTS MAY
DECIDE TO PULL THE TRIGGER BASED ON HOW WIDESPREAD AND HEAVY THE
DAY/S CONVECTIVE DEVELOPMENT PROVES TO BE.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 413 AM EDT THU AUG 8 2013
THE MODELS CONTINUE TO BE IN GOOD AGREEMENT ON THE GENERAL UPPER AIR
PATTERN THAT WILL GUIDE OUR WEATHER THROUGH THE EXTENDED PORTION OF
THE FORECAST. THIS CONSISTS PRIMARILY OF A DEEP AND PERSISTENT
TROUGH OVER SOUTHEAST CANADA AND A FLAT RIDGE OVER THE SOUTHERN TIER
OF THIS NATION. BETWEEN THESE...FAIRLY FAST MID LEVEL FLOW WILL
CARRY SHORT WAVE ENERGY FROM THE WEST COAST THROUGH THE OHIO VALLEY
BEFORE EXITING OFF THE EASTERN SEABOARD. THIS FLOW WILL BE FAIRLY
ZONAL OVER KENTUCKY THROUGH THE WEEKEND BEFORE A WESTERN RESURGENCE
IN THE CANADIAN TROUGH INDUCES A DIP SOUTH THROUGH THE GREAT LAKES
AND INTO THE NORTHERN OHIO VALLEY. THIS WILL RESULT IN MORE OF A
NORTHWEST FLOW PATTERN FOLLOWING THE WEEKEND INTO THE MIDDLE OF NEXT
WEEK. THE GFS AND ECMWF DIFFER MOST DURING THE LATTER PORTION OF THE
FORECAST AS THE ECMWF RUNS A BIT FASTER AND FURTHER EAST WITH THE
CANADIAN LOW/S REDEVELOPMENT INTO THE DAY MONDAY. THE GFS TAKES THE
CORE OF THIS LOW FURTHER SOUTH ON TUESDAY...DIPPING INTO THE
STATES...BEFORE LIFTING IT JUST NORTH OF EAST. DURING THIS TIME OF
LARGER GFS/ECMWF DISCREPANCY THE GEM SEEMS TO BE SIDING WITH THE
ECMWF SO THE MORE EXTREME GFS SOLUTION FOR MONDAY TO WEDNESDAY WILL
BE DISCOUNTED. ALSO...ITS RUN TO RUN CONSISTENCY HAS BEEN POOR...NOT
THAT THE ECMWF HAS BEEN ALL THAT MUCH BETTER/JUST NOT SO OUT THERE
AT TIMES...FOR THE LATTER PART OF THE EXTENDED. ACCORDINGLY...WILL
FAVOR THE BLENDED RESULTS THROUGH THE WEEKEND BEFORE LEANING MORE
TOWARD THE ECMWF INTO THE MIDDLE OF NEXT WEEK.
SENSIBLE WEATHER WILL FEATURE A CONTINUATION OF OUR WET PATTERN THAT
IS PRIMED FOR BOUTS OF HEAVY RAIN. THE SFC BOUNDARY WILL REMAIN
STALLED THROUGH THE REGION INTO THE WEEKEND WITH EACH SFC WAVE
RIPPLING PAST...POTENTIALLY SENDING THE BOUNDARY AND ITS HEAVIEST
RAIN OUR WAY. HIGH PW AIR AND DAYTIME INSTABILITY WILL PROVIDE THE
FUEL FOR THIS MCS ACTIVITY. THEREFORE...POPS WILL REMAIN HIGH INTO
THE WEEKEND WITH MAX TEMPERATURES CAPPED BELOW NORMAL DUE TO CLOUDS
AND CONVECTION. FOR THE START OF NEXT WEEK...IT LOOKS LIKE THE
AMPLIFYING TROUGH ALOFT WILL BE ENOUGH TO EVENTUALLY PUSH THE FRONT
SOUTH OF THE AREA AND ALLOW DRIER AIR TO FLOW INTO THE STATE. THE
FAVORED 12Z ECMWF DOES TAKE THE DEEPER MOISTURE SOUTH LATER MONDAY
WHILE THE GFS WAITS UNTIL A SECONDARY FRONT PUSHES THROUGH ON
TUESDAY NIGHT. WILL CONTINUE SMALL POPS INTO TUESDAY FOR THIS
TRANSITION...BUT NOT AS HIGH AS THE GFS WOULD IMPLY. HOPEFULLY
WEDNESDAY WILL TURN OUT AS PLEASANT AS THE MODEL CONSENSUS SUGGESTS
WITH A RETURN OF DECENT SUNSHINE AND MUCH DRIER AIR. WE WILL SEE...
BUT AT LEAST THIS SEEMS TO BE A BUILDING AND STABILIZING ASPECT OF
THE FORECAST FROM THE LATEST MEDIUM RANGE MODELS.
THE CR GRID LOAD CAME IN NICELY FOR THIS UNSETTLED FORECAST THROUGH
THE WEEKEND. DID TWEAK POPS TO ADD MORE OF A DIURNAL CYCLE AND ALSO
TOWARD THE LATEST SPECIFICS FROM THE 12Z ECMWF FOR MONDAY ON INTO
WEDNESDAY. ONLY MADE MINOR TERRAIN BASED ADJUSTMENTS FOR TEMPS
THROUGHOUT THE BULK OF THIS EXTENDED PERIOD GIVEN THE HIGH MOISTURE
CONTENT...AT LEAST THROUGH TUESDAY MORNING.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 137 AM EDT THU AUG 8 2013
SIMILAR SITUATION TO LAST NIGHT...WITH SCT PRECIP ACROSS THE AREA AND
CLOUD HEIGHTS VARYING FROM POCKETS OF MVFR TO MID LEVEL VFR ACROSS
THE AREA. WHERE THE TAF SITES WILL CONTINUE TO FALL WITHIN THIS
PATTERN WILL BE THE MAIN CONCERN OVERNIGHT. FOR THE MOST
PART...EXPECT VFR CONDITIONS AT TAF SITES UNLESS INFLUENCED BY THE
PASSAGE OF A RAIN SHOWER. BEST CONVECTIVE CHANCES WILL DEVELOP IN THE
MORNING...WITH POSSIBLE MVFR CIGS EXPECTED WITH ONSET. THE EXACT SET
UP OF THESE STORMS IN RELATION TO HOW THEY WILL AFFECT THE TAF SITES
IS STILL SOMEWHAT UNCERTAIN. IF A HEAVY SHOWER OR THUNDERSTORM DOES
IMPACT A SITE DURING THE DAY...VIS COULD TEMPORARILY BE REDUCED BELOW
MVFR. SHOWERS AND THUNDERSTORMS WILL DIE DOWN TOMORROW EVENING WITH
LOSS OF DAYTIME HEATING...THOUGH SOME SCT CONVECTION IS STILL
POSSIBLE THROUGH THE REMAINDER OF THE TAF PERIOD. MUCH LIKE
TONIGHT...EXPECT OVERALL CONDITIONS TO IMPROVE TO VFR WITH SOME
POSSIBLE ADJUSTMENTS IF A SHOWER OR LINGERING THUNDERSTORM PASSES OVER
TAF SITE. AS FAR AS FOG OVERNIGHT...SOME TEMPORARY BR IS BEING
REPORTED AT KJKL IN CONJUNCTION WITH THE RAIN THAT JUST PASSED OVER
INTERACTING WITH THE WARM HUMID CONDITIONS. OTHERWISE...WITH CLOUD COVER
ACROSS MUCH OF THE REGION...ANY WIDESPREAD FOG DEVELOPMENT IS
UNLIKELY...ESPECIALLY TO A DEGREE THAT IT WILL AFFECT THE TAF SITES.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...JMW
LONG TERM...GREIF
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS JACKSON KY
137 AM EDT THU AUG 8 2013
.UPDATE...
ISSUED AT 1214 AM EDT THU AUG 8 2013
UPDATED POPS TO ACCOUNT FOR POSSIBILITY OF DEVELOPMENT OUTSIDE OF
MAIN SHIELD OF PRECIP CURRENTLY OVER THE NW AND CENTRAL CWA.
CONVECTION IN THE CWA SEEMS TO BE FAIRLY LIGHT WITH A DIMINISHING
TREND OVER THE LAST HOUR...BUT EXPECT SOME LIGHT RAIN AND A POSSIBLE
RUMBLE OF THUNDER TO CONTINUE OVER THE NEXT FEW HOURS FOR THE ABOVE
MENTIONED AREAS. MEANWHILE...ISOLATED CONVECTION TO OUR SW WILL MOVE
EASTWARD INTO THE AREA...THEN INCREASE IN COVERAGE AS WE WORK INTO
TOMORROW MORNING. ALSO UPDATED ONGOING TEMPS/DEW POINTS/AND WIND
FORECASTS WITH LATEST OBSERVATIONS TO MAKE SURE THEY REFLECTED THE
MOST CURRENT CONDITIONS.
UPDATE ISSUED AT 1102 PM EDT WED AUG 7 2013
RAIN IS STARTING TO PUSH INTO AREAS FROM MOUNT STERLING TO MOUNT
VERNON...BUT IS BEGINNING TO FALL APART. HRRR SEEMS TO HAVE A GOOD
HANDLE ON THIS TREND WITH THE CURRENT COMPLEX COLLAPSING WITH VERY
LITTLE FOR THE REST OF THE NIGHT. UPDATE HAS BEEN SENT.
UPDATE ISSUED AT 746 PM EDT WED AUG 7 2013
SHOWER AND THUNDERSTORM ACTIVITY HAS DIMINISHED ACROSS EASTERN
KENTUCKY. HAVE SEEN SOME NEW DEVELOPMENT OUT WEST OF LEXINGTON. THIS
ACTIVITY COULD MAKE IT INTO THE I-75 CORRIDOR OVER THE NEXT FEW
HOURS...BUT STILL SOME QUESTION IF THIS WILL MAKE IT INTO AREAS
FURTHER EAST. FOR NOW...GOING TO DOWNPLAY POPS FOR THE REST OF THE
NIGHT GIVEN THE CURRENT LACK OF ORGANIZED ACTIVITY. LATEST HRRR HAS
ALMOST NO SHOWER OR THUNDERSTORM ACTIVITY ACROSS THE AREA UNTIL 11Z.
THUS...THE DOWNWARD TREND IN POPS SEEMS REASONABLE. CAN`T IGNORE
THOSE HIGH PW`S NEAR 2 LATER TONIGHT...SO IT WON`T TAKE MUCH TO GET
SOME LOCALLY HEAVY RAIN...BUT STILL PLANNING TO PUSH ANY MENTION
UNTIL AFTER 12Z.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 315 PM EDT WED AUG 7 2013
AFTER INITIAL ROUND OF SHOWERS AND A FEW THUNDERSTORMS THIS MORNING
CONVECTION HAS REMAINED LIMITED THIS AFTERNOON...WITH MOSTLY
SCATTERED SHOWERS...AND VERY LITTLE THUNDER. CLOUD COVER HAS INHIBITED
DESTABILIZATION AND WITH LOSS OF DAYTIME HEATING EXPECT CONVECTION TO
DIMINISH EVEN FURTHER THIS EVENING.
HOWEVER THIS WILL BE TEMPORARY...WITH A MID LEVEL SHORT WAVE TROUGH
MOVING EAST TONIGHT...AND A LOW LEVEL JET AT 8H IMPINGING ON EASTERN
KY AFTER 06Z. AT THE SAME TIME EXPECT A SURFACE WAVE OF LOW PRESSURE
TO TREK ALONG THE SURFACE FRONT TO THE NORTHWEST OF THE FORECAST AREA
THURSDAY MORNING. THERE IS GOOD MODEL AGREEMENT WITH INCREASING
THREAT OF SHOWERS AND THUNDERSTORMS LATE TONIGHT INTO THE DAY ON
THURSDAY. DETERMINISTIC MODELS ALONG WITH THE SERF ARE POINTING
TOWARDS PRECIPITABLE WATER IN EXCESS OF 2 INCHES BY THURSDAY
MORNING. PRECIPITABLE WATER SHOULD APPROACH OR EXCEED THE 99TH
PERCENTILE. BASED ON THIS WILL ADD THE THREAT OF HEAVY RAIN TO THE
THURSDAY FORECAST AND THE HAZARDOUS WEATHER OUTLOOK. WITH ALL THIS IN
MIND WILL INCREASE RAIN PROBABILITIES LATE TONIGHT TO LIKELY IN THE
WEST...THEN LIKELY ACROSS THE ENTIRE AREA ON THURSDAY...BEFORE
DECREASING CHANCES AGAIN LATE IN THE DAY THURSDAY.
WITH THE FRONT STALLING SOMEWHERE IN THE OH VALLEY...THE TREAT OF
SHOWERS AND THUNDERSTORMS WILL CONTINUE INTO THURSDAY NIGHT. THERE IS
LESS MODEL AGREEMENT ON THE TIMING OF THE NEXT SHORT WAVE WHICH WOULD
TRIGGER ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS BUT FOR FOR NOW
WILL CONTINUE THE PREVIOUS FORECAST IDEA OF INCREASING CHANCES AGAIN
LATE THURSDAY NIGHT.
HIGH DEWPOINTS WILL KEEP MINIMUM TEMPERATURES AROUND 70 TONIGHT AND
AGAIN THURSDAY NIGHT. WITH RAIN AND CLOUD IN THE FORECAST ON
THURSDAY...WILL GO WITH HIGHS IN THE LOWER 80S.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 358 PM EDT WED AUG 7 2013
UNSETTLED WEATHER WILL CONTINUE INTO THE LONG TERM PERIOD. THE PERIOD
SHOULD BEGIN WITH A NEARLY STATIONARY BOUNDARY ACROSS THE OH VALLEY
EXTENDING SOUTHWEST INTO THE OH VALLEY FROM LOW PRESSURE OVER QUEBEC.
THERE MAY BE A WAVE OR SERIES OF SFC WAVES ALONG THE BOUNDARY TO OUR
WEST AT THAT POINT AS DISTURBANCES MOVING INTO THE REGION. AT THE
START OF THE PERIOD UPPER LEVEL RIDGING IS EXPECTED TO EXTEND ACROSS
THE SOUTHERN STATES AND NORTH INTO THE ROCKIES. AN UPPER LEVEL LOW
SHOULD BE ROTATING TO THE NORTH OF THE GREAT LAKES FROM ONTARIO.
THERE WILL PROBABLY BE SOME SHORTWAVES ROTATING TOWARD THE LOWER OH
VALLEY FROM THE PLAINS...BUT THERE ARE MODEL DIFFERENCES IN TIMING.
THE MODELS GRADUALLY SAG THE BOUNDARY SOUTH OF THE OH RIVER AND
EVENTUALLY INTO THE JKL CWA AND STRING IT OUT MORE WEST TO EAST AS THE
UPPER LOW WORKS TOWARD THE MARITIMES OVER THE WEEKEND. FROM EARLY TO
THE MIDDLE PART OF NEXT WEEK...THE TROUGH SHOULD DEEPEN AGAIN OVER
EASTERN CANADA AND THE NORTHEAST AS ANOTHER UPPER LEVEL LOW ROTATES
FROM THE HUDSON BAY REGION NORTH OF THE GREAT LAKES AND TOWARD THE
MARITIMES. THE MODEL CONSENSUS FROM EARLY TO THE MIDDLE PART OF NEXT
WEEK IS FOR MORE AMPLIFIED PATTERN WITH THE BOUNDARY PUSHING SOUTH OF
THE AREA...BUT WEST NORTHWEST UPPER FLOW SHOULD REMAIN. DISTURBANCES
IN THIS FLOW WILL STILL KEEP A THREAT OF CONVECTION IN THE PICTURE
FOR AT LEAST MON AND TUE...ESPECIALLY EACH AFTERNOON AND EVENING.
ENOUGH DRIER AIR MAY WORK INTO THE REGION LATE IN THE PERIOD IF THE
12Z ECMWF VERIFIES FOR DRY WEATHER ON WEDNESDAY OR TUESDAY AND
WEDNESDAY. HOWEVER...MODEL TO MODEL DIFFERENCES AND RUN TO RUN
DIFFERENCE REMAIN AND THE EXTENDED GRID LOAD OF ISOLATED TO
SCATTERED POPS WAS REASONABLE.
PW WILL REMAIN VERY HIGH ABOVE THE 90TH TO 95TH PERCENTILE RANGE INTO
EARLY IN THE PERIOD AHEAD OF THE BOUNDARY. THERE IS THE POTENTIAL FOR
ANY CONVECTION TO HAVE DEEP WARM CLOUD DEPTH AND THEY COULD PRODUCE
AT LEAST LOCALLY HEAVY RAIN. TIMING AND STRENGTH OF PASSING UPPER
LEVEL SHORTWAVES WILL BE A KEY INGREDIENT AND CONFIDENCE IN THIS IS
NOT HIGH AT THIS POINT. HOWEVER...WE WILL HIGHLIGHT THIS IN THE HWO.
TEMPERATURES THROUGH THE PERIOD SHOULD REMAIN NEAR IF NOT A BIT BELOW
NORMAL FOR DAYTIME HIGHS WITH OVERNIGHT LOWS EARLY IN THE PERIOD A
BIT ABOVE NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 137 AM EDT THU AUG 8 2013
SIMILAR SITUATION TO LAST NIGHT...WITH SCT PRECIP ACROSS THE AREA AND
CLOUD HEIGHTS VARYING FROM POCKETS OF MVFR TO MID LEVEL VFR ACROSS
THE AREA. WHERE THE TAF SITES WILL CONTINUE TO FALL WITHIN THIS
PATTERN WILL BE THE MAIN CONCERN OVERNIGHT. FOR THE MOST
PART...EXPECT VFR CONDITIONS AT TAF SITES UNLESS INFLUENCED BY THE
PASSAGE OF A RAIN SHOWER. BEST CONVECTIVE CHANCES WILL DEVELOP IN THE
MORNING...WITH POSSIBLE MVFR CIGS EXPECTED WITH ONSET. THE EXACT SET
UP OF THESE STORMS IN RELATION TO HOW THEY WILL AFFECT THE TAF SITES
IS STILL SOMEWHAT UNCERTAIN. IF A HEAVY SHOWER OR THUNDERSTORM DOES
IMPACT A SITE DURING THE DAY...VIS COULD TEMPORARILY BE REDUCED BELOW
MVFR. SHOWERS AND THUNDERSTORMS WILL DIE DOWN TOMORROW EVENING WITH
LOSS OF DAYTIME HEATING...THOUGH SOME SCT CONVECTION IS STILL
POSSIBLE THROUGH THE REMAINDER OF THE TAF PERIOD. MUCH LIKE
TONIGHT...EXPECT OVERALL CONDITIONS TO IMPROVE TO VFR WITH SOME
POSSIBLE ADJUSTMENTS IF A SHOWER OR LINGERING THUNDERSTORM PASSES OVER
TAF SITE. AS FAR AS FOG OVERNIGHT...SOME TEMPORARY BR IS BEING
REPORTED AT KJKL IN CONJUNCTION WITH THE RAIN THAT JUST PASSED OVER
INTERACTING WITH THE WARM HUMID CONDITIONS. OTHERWISE...WITH CLOUD COVER
ACROSS MUCH OF THE REGION...ANY WIDESPREAD FOG DEVELOPMENT IS
UNLIKELY...ESPECIALLY TO A DEGREE THAT IT WILL AFFECT THE TAF SITES.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JMW
SHORT TERM...SBH
LONG TERM...JP
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS JACKSON KY
1216 AM EDT THU AUG 8 2013
.UPDATE...
ISSUED AT 1214 AM EDT THU AUG 8 2013
UPDATED POPS TO ACCOUNT FOR POSSIBILITY OF DEVELOPMENT OUTSIDE OF
MAIN SHIELD OF PRECIP CURRENTLY OVER THE NW AND CENTRAL CWA.
CONVECTION IN THE CWA SEEMS TO BE FAIRLY LIGHT WITH A DIMINISHING
TREND OVER THE LAST HOUR...BUT EXPECT SOME LIGHT RAIN AND A POSSIBLE
RUMBLE OF THUNDER TO CONTINUE OVER THE NEXT FEW HOURS FOR THE ABOVE
MENTIONED AREAS. MEANWHILE...ISOLATED CONVECTION TO OUR SW WILL MOVE
EASTWARD INTO THE AREA...THEN INCREASE IN COVERAGE AS WE WORK INTO
TOMORROW MORNING. ALSO UPDATED ONGOING TEMPS/DEW POINTS/AND WIND
FORECASTS WITH LATEST OBSERVATIONS TO MAKE SURE THEY REFLECTED THE
MOST CURRENT CONDITIONS.
UPDATE ISSUED AT 1102 PM EDT WED AUG 7 2013
RAIN IS STARTING TO PUSH INTO AREAS FROM MOUNT STERLING TO MOUNT
VERNON...BUT IS BEGINNING TO FALL APART. HRRR SEEMS TO HAVE A GOOD
HANDLE ON THIS TREND WITH THE CURRENT COMPLEX COLLAPSING WITH VERY
LITTLE FOR THE REST OF THE NIGHT. UPDATE HAS BEEN SENT.
UPDATE ISSUED AT 746 PM EDT WED AUG 7 2013
SHOWER AND THUNDERSTORM ACTIVITY HAS DIMINISHED ACROSS EASTERN
KENTUCKY. HAVE SEEN SOME NEW DEVELOPMENT OUT WEST OF LEXINGTON. THIS
ACTIVITY COULD MAKE IT INTO THE I-75 CORRIDOR OVER THE NEXT FEW
HOURS...BUT STILL SOME QUESTION IF THIS WILL MAKE IT INTO AREAS
FURTHER EAST. FOR NOW...GOING TO DOWNPLAY POPS FOR THE REST OF THE
NIGHT GIVEN THE CURRENT LACK OF ORGANIZED ACTIVITY. LATEST HRRR HAS
ALMOST NO SHOWER OR THUNDERSTORM ACTIVITY ACROSS THE AREA UNTIL 11Z.
THUS...THE DOWNWARD TREND IN POPS SEEMS REASONABLE. CAN`T IGNORE
THOSE HIGH PW`S NEAR 2 LATER TONIGHT...SO IT WON`T TAKE MUCH TO GET
SOME LOCALLY HEAVY RAIN...BUT STILL PLANNING TO PUSH ANY MENTION
UNTIL AFTER 12Z.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 315 PM EDT WED AUG 7 2013
AFTER INITIAL ROUND OF SHOWERS AND A FEW THUNDERSTORMS THIS MORNING
CONVECTION HAS REMAINED LIMITED THIS AFTERNOON...WITH MOSTLY
SCATTERED SHOWERS...AND VERY LITTLE THUNDER. CLOUD COVER HAS INHIBITED
DESTABILIZATION AND WITH LOSS OF DAYTIME HEATING EXPECT CONVECTION TO
DIMINISH EVEN FURTHER THIS EVENING.
HOWEVER THIS WILL BE TEMPORARY...WITH A MID LEVEL SHORT WAVE TROUGH
MOVING EAST TONIGHT...AND A LOW LEVEL JET AT 8H IMPINGING ON EASTERN
KY AFTER 06Z. AT THE SAME TIME EXPECT A SURFACE WAVE OF LOW PRESSURE
TO TREK ALONG THE SURFACE FRONT TO THE NORTHWEST OF THE FORECAST AREA
THURSDAY MORNING. THERE IS GOOD MODEL AGREEMENT WITH INCREASING
THREAT OF SHOWERS AND THUNDERSTORMS LATE TONIGHT INTO THE DAY ON
THURSDAY. DETERMINISTIC MODELS ALONG WITH THE SERF ARE POINTING
TOWARDS PRECIPITABLE WATER IN EXCESS OF 2 INCHES BY THURSDAY
MORNING. PRECIPITABLE WATER SHOULD APPROACH OR EXCEED THE 99TH
PERCENTILE. BASED ON THIS WILL ADD THE THREAT OF HEAVY RAIN TO THE
THURSDAY FORECAST AND THE HAZARDOUS WEATHER OUTLOOK. WITH ALL THIS IN
MIND WILL INCREASE RAIN PROBABILITIES LATE TONIGHT TO LIKELY IN THE
WEST...THEN LIKELY ACROSS THE ENTIRE AREA ON THURSDAY...BEFORE
DECREASING CHANCES AGAIN LATE IN THE DAY THURSDAY.
WITH THE FRONT STALLING SOMEWHERE IN THE OH VALLEY...THE TREAT OF
SHOWERS AND THUNDERSTORMS WILL CONTINUE INTO THURSDAY NIGHT. THERE IS
LESS MODEL AGREEMENT ON THE TIMING OF THE NEXT SHORT WAVE WHICH WOULD
TRIGGER ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS BUT FOR FOR NOW
WILL CONTINUE THE PREVIOUS FORECAST IDEA OF INCREASING CHANCES AGAIN
LATE THURSDAY NIGHT.
HIGH DEWPOINTS WILL KEEP MINIMUM TEMPERATURES AROUND 70 TONIGHT AND
AGAIN THURSDAY NIGHT. WITH RAIN AND CLOUD IN THE FORECAST ON
THURSDAY...WILL GO WITH HIGHS IN THE LOWER 80S.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 358 PM EDT WED AUG 7 2013
UNSETTLED WEATHER WILL CONTINUE INTO THE LONG TERM PERIOD. THE PERIOD
SHOULD BEGIN WITH A NEARLY STATIONARY BOUNDARY ACROSS THE OH VALLEY
EXTENDING SOUTHWEST INTO THE OH VALLEY FROM LOW PRESSURE OVER QUEBEC.
THERE MAY BE A WAVE OR SERIES OF SFC WAVES ALONG THE BOUNDARY TO OUR
WEST AT THAT POINT AS DISTURBANCES MOVING INTO THE REGION. AT THE
START OF THE PERIOD UPPER LEVEL RIDGING IS EXPECTED TO EXTEND ACROSS
THE SOUTHERN STATES AND NORTH INTO THE ROCKIES. AN UPPER LEVEL LOW
SHOULD BE ROTATING TO THE NORTH OF THE GREAT LAKES FROM ONTARIO.
THERE WILL PROBABLY BE SOME SHORTWAVES ROTATING TOWARD THE LOWER OH
VALLEY FROM THE PLAINS...BUT THERE ARE MODEL DIFFERENCES IN TIMING.
THE MODELS GRADUALLY SAG THE BOUNDARY SOUTH OF THE OH RIVER AND
EVENTUALLY INTO THE JKL CWA AND STRING IT OUT MORE WEST TO EAST AS THE
UPPER LOW WORKS TOWARD THE MARITIMES OVER THE WEEKEND. FROM EARLY TO
THE MIDDLE PART OF NEXT WEEK...THE TROUGH SHOULD DEEPEN AGAIN OVER
EASTERN CANADA AND THE NORTHEAST AS ANOTHER UPPER LEVEL LOW ROTATES
FROM THE HUDSON BAY REGION NORTH OF THE GREAT LAKES AND TOWARD THE
MARITIMES. THE MODEL CONSENSUS FROM EARLY TO THE MIDDLE PART OF NEXT
WEEK IS FOR MORE AMPLIFIED PATTERN WITH THE BOUNDARY PUSHING SOUTH OF
THE AREA...BUT WEST NORTHWEST UPPER FLOW SHOULD REMAIN. DISTURBANCES
IN THIS FLOW WILL STILL KEEP A THREAT OF CONVECTION IN THE PICTURE
FOR AT LEAST MON AND TUE...ESPECIALLY EACH AFTERNOON AND EVENING.
ENOUGH DRIER AIR MAY WORK INTO THE REGION LATE IN THE PERIOD IF THE
12Z ECMWF VERIFIES FOR DRY WEATHER ON WEDNESDAY OR TUESDAY AND
WEDNESDAY. HOWEVER...MODEL TO MODEL DIFFERENCES AND RUN TO RUN
DIFFERENCE REMAIN AND THE EXTENDED GRID LOAD OF ISOLATED TO
SCATTERED POPS WAS REASONABLE.
PW WILL REMAIN VERY HIGH ABOVE THE 90TH TO 95TH PERCENTILE RANGE INTO
EARLY IN THE PERIOD AHEAD OF THE BOUNDARY. THERE IS THE POTENTIAL FOR
ANY CONVECTION TO HAVE DEEP WARM CLOUD DEPTH AND THEY COULD PRODUCE
AT LEAST LOCALLY HEAVY RAIN. TIMING AND STRENGTH OF PASSING UPPER
LEVEL SHORTWAVES WILL BE A KEY INGREDIENT AND CONFIDENCE IN THIS IS
NOT HIGH AT THIS POINT. HOWEVER...WE WILL HIGHLIGHT THIS IN THE HWO.
TEMPERATURES THROUGH THE PERIOD SHOULD REMAIN NEAR IF NOT A BIT BELOW
NORMAL FOR DAYTIME HIGHS WITH OVERNIGHT LOWS EARLY IN THE PERIOD A
BIT ABOVE NORMAL.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 746 PM EDT WED AUG 7 2013
SHOWERS HAVE DIMINISHED ACROSS EASTERN KENTUCKY AND TAFS WILL ALL
START OFF VFR. WITH LOTS OF LOW LEVEL MOISTURE PRESENT...SOME STRATUS
SHOULD DEVELOP OVERNIGHT...MUCH LIKE LAST NIGHT. IN ADDITION SOME
RAIN COULD START TO INVADE THE AREA TOWARDS DAYBREAK. WITH CLOUD
COVER FAIRLY HIGH TONIGHT...NO FOG EXPECTED AT THE TAF SITES.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JMW
SHORT TERM...SBH
LONG TERM...JP
AVIATION...KAS
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
1154 AM EDT THU AUG 8 2013
.SYNOPSIS...
A WARM FRONT WILL LIFT INTO THE AREA TODAY AND STALL ACROSS THE
HIGHER TERRAIN THROUGH FRIDAY. A COLD FRONT MOVES THROUGH ON
FRIDAY AND FRIDAY EVENING. HIGH PRESSURE BUILDS IN FOR THE END OF
THE WEEKEND AND INTO EARLY NEXT WEEK. LOW PRESSURE WILL APPROACH
FROM THE WEST IN THE MIDDLE OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
.UPDATE...
PLENTY OF CLEARING/INSOLATION TO OUR WEST IN NY BUT LITTLE SUN
THIS FAR EAST. SOME STORMS STILL EXPECTED LATER THIS AFTERNOON AND
EVENING...ESPECIALLY OVER SOUTHERN NH AND NORTHERN MAINE WITH
SURFACE TROUGH IN THE AREA. HAVE UPDATED TEMPERATURES...DEW
POINTS...AND POPS. POPS WERE LOWERED QUITE A BIT AND ONLY
EXPECTING 20-40% COVERAGE THIS EVENING.
&&
PREVIOUS DISCUSSION...
FIRST LINE OF SHOWERS HAS NOW EXITED THE FORECAST AREA. HAVE
ADJUSTED POPS DOWN QUITE A BIT. MOST AREAS ARE STILL OVERCAST BUT
THERE ARE A FEW BREAKS SHOWING UP IN NORTHERN NH. THIS TREND
SHOULD CONTINUE AS NEXT SURFACE TROUGH ARRIVES LATER THIS AFTERNOON.
SHOULD GET ENOUGH INSOLATION FOR A FEW STORMS DEVELOPING/MOVING
OUT OF VT EARLY THIS AFTERNOON. HRRR INITIALIZES WELL AND HAVE
FOLLOWED IT FOR THIS AFTERNOON`S CONVECTION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
ATTENTION THEN TURNS TO FNT STALLING ALONG OR S OF THE SRN CWFA
BORDER. TO THE S WILL BE AN EXTREMELY MOIST AIR MASS...WITH PWAT
VALUES INCREASING TO NEAR 2 INCHES. FOR THE GYX AREA THIS
REPRESENTATION AOA +2 SD ABOVE NORMAL. HEAVY RNFL IS LIKELY WITH
ANY CONVECTION...WITH EXTREME RNFL RATES AT TIMES. IN
ADDITION...BOUNDARY WILL PROVIDE A FOCUS FOR TRAINING CELLS. ATTM
UNCERTAINTY STILL EXISTS ON LOCATION FNT STALLS...BUT AS
CONFIDENCE GROWS SOME SORT OF FLOOD/FLASH FLOOD HEADLINE MAY BE
NECESSARY FOR A PORTION OF THE AREA. MUCH OF THAT MAY ALSO DEPEND
ON WHERE HEAVY RAIN FALLS TODAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
A COLD FRONT WILL SLOWLY PUSH THROUGH THE REGION FRIDAY
EVENING...SWEEPING THE HIGHER SURFACE DEW POINTS AND PRECIPITABLE
WATER VALUES OFF THE COAST. MODELS STILL HAVE SOME ISSUES WITH THE
TIMING OF THE PASSAGE OF THE FRONT. HAVE USED A BLEND BETWEEN THE
VERY PROGRESSIVE...FAST MOVING FRONTAL PASSAGE WITH THE GFS/EURO
SOLUTION...AND THE SLOWER FROPA WITH THE NAM/GGEM SOLUTION.
SURFACE HIGH PRESSURE BEGINS TO BUILD IN FROM THE WEST ON
SATURDAY. HOWEVER...STILL PLENTY OF COLD AIR AND CYCLONIC FLOW ALOFT
ALLOWING FOR A FEW DIURNALLY DRIVEN SPRINKLES OR SCATTERED
SHOWERS...MAINLY ACROSS THE HIGHER TERRAIN OF THE MOUNTAINS. THIS
AIR MASS WILL BE NOTICEABLY COOLER AND DRIER. EXPECT CHILLY NIGHTS
WITH PATCHY FOG AS THIS SYSTEM BUILDS OVERHEAD.
MODELS IN GOOD AGREEMENT ADVANCING THE AREA OF HIGH PRESSURE OVER
OUR REGION SUNDAY INTO MONDAY. BY TUESDAY...LOW PRESSURE WILL
BEGIN TO EXIT THE GREAT LAKES REGION...BRINGING MORE SCATTERED
SHOWERS TO OUR REGION DURING THE MIDWEEK PERIOD.
&&
.AVIATION /16Z THURSDAY THROUGH MONDAY/...
SHORT TERM...CONDS EXPECTED TO DETERIORATE INTO GENERALLY MVFR
CIGS AND VSBYS AS FNT APPROACHES TODAY. SOME LOCAL IFR IS PSBL IN
NEAR COAST STRATUS OR SHRA/TSTM. IFR CONDS COULD BECOME MORE
WIDESPREAD NEAR THE COAST AS FNT STALL TONIGHT AND FRI AND DEEPER
MOISTURE WORKS NWD.
LONG TERM...SHOWERS AND A FEW EMBEDDED THUNDERSTORMS EARLY FRIDAY
EVENING MAY BRING MVFR TO IFR CONDITIONS. EXPECT IMPROVING
CONDITIONS BEHIND A COLD FRONT FRIDAY NIGHT WITH VFR CONDITIONS
CONTINUING INTO EARLY NEXT WEEK.
&&
.MARINE...
SHORT TERM...SUSTAINED ONSHORE FLOW WILL DEVELOP TODAY AHEAD OF AN
APPROACHING FNT. THIS WILL GRADUALLY BUILD SEAS TO NEAR 5 FT BY
LATE THIS EVENING...DESPITE WINDS REMAINING BLO 25 KTS. USED A
BLEND OF THE NAM BASED SWAN WITH THE WNA4 IN THE FIRST PERIOD...AS
GFS IS USUALLY TOO AGGRESSIVE WITH WINDS AND SEAS IN SLY FLOW.
LONG TERM...SOUTHERLY FLOW WILL END FRIDAY EVENING. HOWEVER SEAS
STILL EXPECTED TO BE RELATIVELY HIGH IN THE 4 TO 6 FOOT RANGE.
THEREFORE....SMALL CRAFT ADVISORIES MAY STILL BE NEEDED THROUGH
MUCH OF FRIDAY NIGHT AND POSSIBLY INTO EARLY SATURDAY MORNING.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
UPDATE...HANES
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
942 AM EDT THU AUG 8 2013
.SYNOPSIS...
A WARM FRONT WILL LIFT INTO THE AREA TODAY AND STALL ACROSS THE
HIGHER TERRAIN THROUGH FRIDAY. A COLD FRONT MOVES THROUGH ON
FRIDAY AND FRIDAY EVENING. HIGH PRESSURE BUILDS IN FOR THE END OF
THE WEEKEND AND INTO EARLY NEXT WEEK. LOW PRESSURE WILL APPROACH
FROM THE WEST IN THE MIDDLE OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
FIRST LINE OF SHOWERS HAS NOW EXITED THE FORECAST AREA. HAVE
ADJUSTED POPS DOWN QUITE A BIT. MOST AREAS ARE STILL OVERCAST BUT
THERE ARE A FEW BREAKS SHOWING UP IN NORTHERN NH. THIS TREND
SHOULD CONTINUE AS NEXT SURFACE TROUGH ARRIVES LATER THIS AFTERNOON.
SHOULD GET ENOUGH INSOLATION FOR A FEW STORMS DEVELOPING/MOVING
OUT OF VT EARLY THIS AFTERNOON. HRRR INITIALIZES WELL AND HAVE
FOLLOWED IT FOR THIS AFTERNOON`S CONVECTION.
&&
PREVIOUS DISCUSSION...FNT WILL APPROACH THE AREA TODAY AND BRING
AT LEAST A COUPLE ROUNDS OF SHRA/TSTMS.
EARLY TODAY AN INCREASINGLY MOISTENING ATMOSPHERE WILL RESULT IN
CLOUDS SPREADING EWD AND THICKENING. ADDITIONALLY...WAA WILL
SUPPORT WIDELY SCT SHRA ACROSS THE AREA THRU SUNRISE. A LINE OF
SHRA AND TSTMS ALONG THE FNT WILL ALSO PUSH EWD INTO WRN ZONES IN
THE NEXT SEVERAL HOURS. SO IN THE NEAR TERM HAVE TRIED TO TIME
POP WITH THIS TREND...WHICH THE HRRR SEEM TO HAVE A DECENT HANDLE
ON. A BLEND OF THAT AND THE LOCAL WRF WAS USED AS THE BASE FOR THE
FIRST HALF OF THE DAY.
AS THIS EARLY CONVECTION WEAKENS AND MOVES E...EXPECT THAT A FEW
PARTIAL BREAKS IN THE OVERCAST WILL DEVELOP THIS AFTERNOON. IT IS
THESE POCKETS OF SFC HEATING THAT WILL BECOME THE FOCUS FOR THE
AFTERNOON FORECAST. LAPSE RATES ARE MARGINAL AT BEST...BUT DEW
POINTS INCREASING TO THE UPR 60S TO NEAR 70 WILL SUPPORT MODERATE
INSTABILITY FOR LOCATIONS THAT CAN GLIMPSE SOME SUNSHINE. AMPLE
MID LVL WLY FLOW WILL SUPPORT ENOUGH EFFECTIVE SHEAR FOR SOME
STORM ORGANIZATION. AT LEAST TRANSIENT SUPERCELL STRUCTURE WILL
LEAD TO STRONGER CONVECTION CONTAINING GUSTY WINDS AND SMALL HAIL.
GREATER THREAT IS PROBABLY WIND...AS DEEP...MOIST AIR MASS WILL BE
MORE SUPPORTIVE OF MELTING HAIL. PCPN LOADING IN THE COLUMN AND
STEEP LLVL LAPSE RATES WHERE SUN PEEKS OUT IS MORE THAN ENOUGH FOR
SOME GUSTY DOWNDRAFTS. THIS HAS BEEN ADDED TO THE GRIDS...MAINLY
ACROSS NH AND EXTREME WRN ME. NOT EXPECTING ANYTHING
WIDESPREAD...BUT AN ISOLD SEVERE WX REPORT IS ENTIRELY PSBL TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
ATTENTION THEN TURNS TO FNT STALLING ALONG OR S OF THE SRN CWFA
BORDER. TO THE S WILL BE AN EXTREMELY MOIST AIR MASS...WITH PWAT
VALUES INCREASING TO NEAR 2 INCHES. FOR THE GYX AREA THIS
REPRESENTATION AOA +2 SD ABOVE NORMAL. HEAVY RNFL IS LIKELY WITH
ANY CONVECTION...WITH EXTREME RNFL RATES AT TIMES. IN
ADDITION...BOUNDARY WILL PROVIDE A FOCUS FOR TRAINING CELLS. ATTM
UNCERTAINTY STILL EXISTS ON LOCATION FNT STALLS...BUT AS
CONFIDENCE GROWS SOME SORT OF FLOOD/FLASH FLOOD HEADLINE MAY BE
NECESSARY FOR A PORTION OF THE AREA. MUCH OF THAT MAY ALSO DEPEND
ON WHERE HEAVY RAIN FALLS TODAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
A COLD FRONT WILL SLOWLY PUSH THROUGH THE REGION FRIDAY
EVENING...SWEEPING THE HIGHER SURFACE DEW POINTS AND PRECIPITABLE
WATER VALUES OFF THE COAST. MODELS STILL HAVE SOME ISSUES WITH THE
TIMING OF THE PASSAGE OF THE FRONT. HAVE USED A BLEND BETWEEN THE
VERY PROGRESSIVE...FAST MOVING FRONTAL PASSAGE WITH THE GFS/EURO
SOLUTION...AND THE SLOWER FROPA WITH THE NAM/GGEM SOLUTION.
SURFACE HIGH PRESSURE BEGINS TO BUILD IN FROM THE WEST ON
SATURDAY. HOWEVER...STILL PLENTY OF COLD AIR AND CYCLONIC FLOW ALOFT
ALLOWING FOR A FEW DIURNALLY DRIVEN SPRINKLES OR SCATTERED
SHOWERS...MAINLY ACROSS THE HIGHER TERRAIN OF THE MOUNTAINS. THIS
AIR MASS WILL BE NOTICEABLY COOLER AND DRIER. EXPECT CHILLY NIGHTS
WITH PATCHY FOG AS THIS SYSTEM BUILDS OVERHEAD.
MODELS IN GOOD AGREEMENT ADVANCING THE AREA OF HIGH PRESSURE OVER
OUR REGION SUNDAY INTO MONDAY. BY TUESDAY...LOW PRESSURE WILL
BEGIN TO EXIT THE GREAT LAKES REGION...BRINGING MORE SCATTERED
SHOWERS TO OUR REGION DURING THE MIDWEEK PERIOD.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
SHORT TERM...CONDS EXPECTED TO DETERIORATE INTO GENERALLY MVFR
CIGS AND VSBYS AS FNT APPROACHES TODAY. SOME LOCAL IFR IS PSBL IN
NEAR COAST STRATUS OR SHRA/TSTM. IFR CONDS COULD BECOME MORE
WIDESPREAD NEAR THE COAST AS FNT STALL TONIGHT AND FRI AND DEEPER
MOISTURE WORKS NWD.
LONG TERM...SHOWERS AND A FEW EMBEDDED THUNDERSTORMS EARLY FRIDAY
EVENING MAY BRING MVFR TO IFR CONDITIONS. EXPECT IMPROVING
CONDITIONS BEHIND A COLD FRONT FRIDAY NIGHT WITH VFR CONDITIONS
CONTINUING INTO EARLY NEXT WEEK.
&&
.MARINE...
SHORT TERM...SUSTAINED ONSHORE FLOW WILL DEVELOP TODAY AHEAD OF AN
APPROACHING FNT. THIS WILL GRADUALLY BUILD SEAS TO NEAR 5 FT BY
LATE THIS EVENING...DESPITE WINDS REMAINING BLO 25 KTS. USED A
BLEND OF THE NAM BASED SWAN WITH THE WNA4 IN THE FIRST PERIOD...AS
GFS IS USUALLY TOO AGGRESSIVE WITH WINDS AND SEAS IN SLY FLOW.
LONG TERM...SOUTHERLY FLOW WILL END FRIDAY EVENING. HOWEVER SEAS
STILL EXPECTED TO BE RELATIVELY HIGH IN THE 4 TO 6 FOOT RANGE.
THEREFORE....SMALL CRAFT ADVISORIES MAY STILL BE NEEDED THROUGH
MUCH OF FRIDAY NIGHT AND POSSIBLY INTO EARLY SATURDAY MORNING.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
UPDATE...HANES
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
544 AM EDT THU AUG 8 2013
.SYNOPSIS...
A WARM FRONT WILL LIFT INTO THE AREA TODAY AND STALL ACROSS THE
HIGHER TERRAIN THROUGH FRIDAY. A COLD FRONT MOVES THROUGH ON
FRIDAY AND FRIDAY EVENING. HIGH PRESSURE BUILDS IN FOR THE END OF
THE WEEKEND AND INTO EARLY NEXT WEEK. LOW PRESSURE WILL APPROACH
FROM THE WEST IN THE MIDDLE OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATE...SCT WAA SHRA ARE PUSHING ACROSS THE AREA ATTM...ROUGHLY
ALIGNED WITH NH/ME BORDER. A FEW OF THE STRONGER CELLS HAVE HAD
SOME IN CLOUD LIGHTNING WITH THEM...BUT MOSTLY JUST SOME BRIEF
-SHRA. THIS WAVE OF PCPN WILL CONTINUE EWD THRU THE MORNING HOURS.
FARTHER W...BROKEN LINE OF SHRA/TSTMS FROM THE ST. LAWRENCE VALLEY
SWWD TOWARDS KBUF CONTINUES TO TRACK EWD. COMPLEX OF TSTMS NEAR
THE EASTERN TOWNSHIPS WILL LIKELY EFFECT NRN COOS AND THE WRN ME
MTNS. SATELLITE TRENDS SUGGEST WEAKENING IS OCCURRING...WITH CLOUD
TOPS WARMING AND LIGHTNING DECREASING. ACROSS WRN NY...COMPLEX OF
TSTMS THERE IS MAINTAINING STRENGTH WITH CLOUD TOPS COOLING AND
LIGHTNING INCREASING. THIS GROWING COMPLEX MAY BE THE REASON FOR
THE RELATIVE LACK OF CONVECTIVE ACTIVITY ACROSS THE ADIRONDACKS
AND VT. HAVE TRENDED POP BASED ON THE LATEST HRRR AND RADAR.
PREVIOUS DISCUSSION...FNT WILL APPROACH THE AREA TODAY AND BRING
AT LEAST A COUPLE ROUNDS OF SHRA/TSTMS.
EARLY TODAY AN INCREASINGLY MOISTENING ATMOSPHERE WILL RESULT IN
CLOUDS SPREADING EWD AND THICKENING. ADDITIONALLY...WAA WILL
SUPPORT WIDELY SCT SHRA ACROSS THE AREA THRU SUNRISE. A LINE OF
SHRA AND TSTMS ALONG THE FNT WILL ALSO PUSH EWD INTO WRN ZONES IN
THE NEXT SEVERAL HOURS. SO IN THE NEAR TERM HAVE TRIED TO TIME
POP WITH THIS TREND...WHICH THE HRRR SEEM TO HAVE A DECENT HANDLE
ON. A BLEND OF THAT AND THE LOCAL WRF WAS USED AS THE BASE FOR THE
FIRST HALF OF THE DAY.
AS THIS EARLY CONVECTION WEAKENS AND MOVES E...EXPECT THAT A FEW
PARTIAL BREAKS IN THE OVERCAST WILL DEVELOP THIS AFTERNOON. IT IS
THESE POCKETS OF SFC HEATING THAT WILL BECOME THE FOCUS FOR THE
AFTERNOON FORECAST. LAPSE RATES ARE MARGINAL AT BEST...BUT DEW
POINTS INCREASING TO THE UPR 60S TO NEAR 70 WILL SUPPORT MODERATE
INSTABILITY FOR LOCATIONS THAT CAN GLIMPSE SOME SUNSHINE. AMPLE
MID LVL WLY FLOW WILL SUPPORT ENOUGH EFFECTIVE SHEAR FOR SOME
STORM ORGANIZATION. AT LEAST TRANSIENT SUPERCELL STRUCTURE WILL
LEAD TO STRONGER CONVECTION CONTAINING GUSTY WINDS AND SMALL HAIL.
GREATER THREAT IS PROBABLY WIND...AS DEEP...MOIST AIR MASS WILL BE
MORE SUPPORTIVE OF MELTING HAIL. PCPN LOADING IN THE COLUMN AND
STEEP LLVL LAPSE RATES WHERE SUN PEEKS OUT IS MORE THAN ENOUGH FOR
SOME GUSTY DOWNDRAFTS. THIS HAS BEEN ADDED TO THE GRIDS...MAINLY
ACROSS NH AND EXTREME WRN ME. NOT EXPECTING ANYTHING
WIDESPREAD...BUT AN ISOLD SEVERE WX REPORT IS ENTIRELY PSBL TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
ATTENTION THEN TURNS TO FNT STALLING ALONG OR S OF THE SRN CWFA
BORDER. TO THE S WILL BE AN EXTREMELY MOIST AIR MASS...WITH PWAT
VALUES INCREASING TO NEAR 2 INCHES. FOR THE GYX AREA THIS
REPRESENTATION AOA +2 SD ABOVE NORMAL. HEAVY RNFL IS LIKELY WITH
ANY CONVECTION...WITH EXTREME RNFL RATES AT TIMES. IN
ADDITION...BOUNDARY WILL PROVIDE A FOCUS FOR TRAINING CELLS. ATTM
UNCERTAINTY STILL EXISTS ON LOCATION FNT STALLS...BUT AS
CONFIDENCE GROWS SOME SORT OF FLOOD/FLASH FLOOD HEADLINE MAY BE
NECESSARY FOR A PORTION OF THE AREA. MUCH OF THAT MAY ALSO DEPEND
ON WHERE HEAVY RAIN FALLS TODAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
A COLD FRONT WILL SLOWLY PUSH THROUGH THE REGION FRIDAY
EVENING...SWEEPING THE HIGHER SURFACE DEW POINTS AND PRECIPITABLE
WATER VALUES OFF THE COAST. MODELS STILL HAVE SOME ISSUES WITH THE
TIMING OF THE PASSAGE OF THE FRONT. HAVE USED A BLEND BETWEEN THE
VERY PROGRESSIVE...FAST MOVING FRONTAL PASSAGE WITH THE GFS/EURO
SOLUTION...AND THE SLOWER FROPA WITH THE NAM/GGEM SOLUTION.
SURFACE HIGH PRESSURE BEGINS TO BUILD IN FROM THE WEST ON
SATURDAY. HOWEVER...STILL PLENTY OF COLD AIR AND CYCLONIC FLOW ALOFT
ALLOWING FOR A FEW DIURNALLY DRIVEN SPRINKLES OR SCATTERED
SHOWERS...MAINLY ACROSS THE HIGHER TERRAIN OF THE MOUNTAINS. THIS
AIR MASS WILL BE NOTICEABLY COOLER AND DRIER. EXPECT CHILLY NIGHTS
WITH PATCHY FOG AS THIS SYSTEM BUILDS OVERHEAD.
MODELS IN GOOD AGREEMENT ADVANCING THE AREA OF HIGH PRESSURE OVER
OUR REGION SUNDAY INTO MONDAY. BY TUESDAY...LOW PRESSURE WILL
BEGIN TO EXIT THE GREAT LAKES REGION...BRINGING MORE SCATTERED
SHOWERS TO OUR REGION DURING THE MIDWEEK PERIOD.
&&
.AVIATION /10Z THURSDAY THROUGH MONDAY/...
SHORT TERM...CONDS EXPECTED TO DETERIORATE INTO GENERALLY MVFR
CIGS AND VSBYS AS FNT APPROACHES TODAY. SOME LOCAL IFR IS PSBL IN
NEAR COAST STRATUS OR SHRA/TSTM. IFR CONDS COULD BECOME MORE
WIDESPREAD NEAR THE COAST AS FNT STALL TONIGHT AND FRI AND DEEPER
MOISTURE WORKS NWD.
LONG TERM...SHOWERS AND A FEW EMBEDDED THUNDERSTORMS EARLY FRIDAY
EVENING MAY BRING MVFR TO IFR CONDITIONS. EXPECT IMPROVING
CONDITIONS BEHIND A COLD FRONT FRIDAY NIGHT WITH VFR CONDITIONS
CONTINUING INTO EARLY NEXT WEEK.
&&
.MARINE...
SHORT TERM...SUSTAINED ONSHORE FLOW WILL DEVELOP TODAY AHEAD OF AN
APPROACHING FNT. THIS WILL GRADUALLY BUILD SEAS TO NEAR 5 FT BY
LATE THIS EVENING...DESPITE WINDS REMAINING BLO 25 KTS. USED A
BLEND OF THE NAM BASED SWAN WITH THE WNA4 IN THE FIRST PERIOD...AS
GFS IS USUALLY TOO AGGRESSIVE WITH WINDS AND SEAS IN SLY FLOW.
LONG TERM...SOUTHERLY FLOW WILL END FRIDAY EVENING. HOWEVER SEAS
STILL EXPECTED TO BE RELATIVELY HIGH IN THE 4 TO 6 FOOT RANGE.
THEREFORE....SMALL CRAFT ADVISORIES MAY STILL BE NEEDED THROUGH
MUCH OF FRIDAY NIGHT AND POSSIBLY INTO EARLY SATURDAY MORNING.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
LEGRO/JC
AREA FORECAST DISCUSSION
NWS GRAY ME
318 AM EDT THU AUG 8 2013
.SYNOPSIS...
A WARM FRONT WILL LIFT INTO THE AREA TODAY AND STALL ACROSS THE
HIGHER TERRAIN THROUGH FRIDAY. A COLD FRONT MOVES THROUGH ON
FRIDAY AND FRIDAY EVENING. HIGH PRESSURE BUILDS IN FOR THE END OF
THE WEEKEND AND INTO EARLY NEXT WEEK. LOW PRESSURE WILL APPROACH
FROM THE WEST IN THE MIDDLE OF THE WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
FNT WILL APPROACH THE AREA TODAY AND BRING AT LEAST A COUPLE ROUNDS
OF SHRA/TSTMS.
EARLY TODAY AN INCREASINGLY MOISTENING ATMOSPHERE WILL RESULT IN
CLOUDS SPREADING EWD AND THICKENING. ADDITIONALLY...WAA WILL
SUPPORT WIDELY SCT SHRA ACROSS THE AREA THRU SUNRISE. A LINE OF
SHRA AND TSTMS ALONG THE FNT WILL ALSO PUSH EWD INTO WRN ZONES IN
THE NEXT SEVERAL HOURS. SO IN THE NEAR TERM HAVE TRIED TO TIME
POP WITH THIS TREND...WHICH THE HRRR SEEM TO HAVE A DECENT HANDLE
ON. A BLEND OF THAT AND THE LOCAL WRF WAS USED AS THE BASE FOR THE
FIRST HALF OF THE DAY.
AS THIS EARLY CONVECTION WEAKENS AND MOVES E...EXPECT THAT A FEW
PARTIAL BREAKS IN THE OVERCAST WILL DEVELOP THIS AFTERNOON. IT IS
THESE POCKETS OF SFC HEATING THAT WILL BECOME THE FOCUS FOR THE
AFTERNOON FORECAST. LAPSE RATES ARE MARGINAL AT BEST...BUT DEW
POINTS INCREASING TO THE UPR 60S TO NEAR 70 WILL SUPPORT MODERATE
INSTABILITY FOR LOCATIONS THAT CAN GLIMPSE SOME SUNSHINE. AMPLE
MID LVL WLY FLOW WILL SUPPORT ENOUGH EFFECTIVE SHEAR FOR SOME
STORM ORGANIZATION. AT LEAST TRANSIENT SUPERCELL STRUCTURE WILL
LEAD TO STRONGER CONVECTION CONTAINING GUSTY WINDS AND SMALL HAIL.
GREATER THREAT IS PROBABLY WIND...AS DEEP...MOIST AIR MASS WILL BE
MORE SUPPORTIVE OF MELTING HAIL. PCPN LOADING IN THE COLUMN AND
STEEP LLVL LAPSE RATES WHERE SUN PEEKS OUT IS MORE THAN ENOUGH FOR
SOME GUSTY DOWNDRAFTS. THIS HAS BEEN ADDED TO THE GRIDS...MAINLY
ACROSS NH AND EXTREME WRN ME. NOT EXPECTING ANYTHING
WIDESPREAD...BUT AN ISOLD SEVERE WX REPORT IS ENTIRELY PSBL TODAY.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM FRIDAY/...
ATTENTION THEN TURNS TO FNT STALLING ALONG OR S OF THE SRN CWFA
BORDER. TO THE S WILL BE AN EXTREMELY MOIST AIR MASS...WITH PWAT
VALUES INCREASING TO NEAR 2 INCHES. FOR THE GYX AREA THIS
REPRESENTATION AOA +2 SD ABOVE NORMAL. HEAVY RNFL IS LIKELY WITH
ANY CONVECTION...WITH EXTREME RNFL RATES AT TIMES. IN
ADDITION...BOUNDARY WILL PROVIDE A FOCUS FOR TRAINING CELLS. ATTM
UNCERTAINTY STILL EXISTS ON LOCATION FNT STALLS...BUT AS
CONFIDENCE GROWS SOME SORT OF FLOOD/FLASH FLOOD HEADLINE MAY BE
NECESSARY FOR A PORTION OF THE AREA. MUCH OF THAT MAY ALSO DEPEND
ON WHERE HEAVY RAIN FALLS TODAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
A COLD FRONT WILL SLOWLY PUSH THROUGH THE REGION FRIDAY
EVENING...SWEEPING THE HIGHER SURFACE DEW POINTS AND PRECIPITABLE
WATER VALUES OFF THE COAST. MODELS STILL HAVE SOME ISSUES WITH THE
TIMING OF THE PASSAGE OF THE FRONT. HAVE USED A BLEND BETWEEN THE
VERY PROGRESSIVE...FAST MOVING FRONTAL PASSAGE WITH THE GFS/EURO
SOLUTION...AND THE SLOWER FROPA WITH THE NAM/GGEM SOLUTION.
SURFACE HIGH PRESSURE BEGINS TO BUILD IN FROM THE WEST ON
SATURDAY. HOWEVER...STILL PLENTY OF COLD AIR AND CYCLONIC FLOW ALOFT
ALLOWING FOR A FEW DIURNALLY DRIVEN SPRINKLES OR SCATTERED
SHOWERS...MAINLY ACROSS THE HIGHER TERRAIN OF THE MOUNTAINS. THIS
AIR MASS WILL BE NOTICEABLY COOLER AND DRIER. EXPECT CHILLY NIGHTS
WITH PATCHY FOG AS THIS SYSTEM BUILDS OVERHEAD.
MODELS IN GOOD AGREEMENT ADVANCING THE AREA OF HIGH PRESSURE OVER
OUR REGION SUNDAY INTO MONDAY. BY TUESDAY...LOW PRESSURE WILL
BEGIN TO EXIT THE GREAT LAKES REGION...BRINGING MORE SCATTERED
SHOWERS TO OUR REGION DURING THE MIDWEEK PERIOD.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
SHORT TERM...CONDS EXPECTED TO DETERIORATE INTO GENERALLY MVFR
CIGS AND VSBYS AS FNT APPROACHES TODAY. SOME LOCAL IFR IS PSBL IN
NEAR COAST STRATUS OR SHRA/TSTM. IFR CONDS COULD BECOME MORE
WIDESPREAD NEAR THE COAST AS FNT STALL TONIGHT AND FRI AND DEEPER
MOISTURE WORKS NWD.
LONG TERM...SHOWERS AND A FEW EMBEDDED THUNDERSTORMS EARLY FRIDAY
EVENING MAY BRING MVFR TO IFR CONDITIONS. EXPECT IMPROVING
CONDITIONS BEHIND A COLD FRONT FRIDAY NIGHT WITH VFR CONDITIONS
CONTINUING INTO EARLY NEXT WEEK.
&&
.MARINE...
SHORT TERM...SUSTAINED ONSHORE FLOW WILL DEVELOP TODAY AHEAD OF AN
APPROACHING FNT. THIS WILL GRADUALLY BUILD SEAS TO NEAR 5 FT BY
LATE THIS EVENING...DESPITE WINDS REMAINING BLO 25 KTS. USED A
BLEND OF THE NAM BASED SWAN WITH THE WNA4 IN THE FIRST PERIOD...AS
GFS IS USUALLY TOO AGGRESSIVE WITH WINDS AND SEAS IN SLY FLOW.
LONG TERM...SOUTHERLY FLOW WILL END FRIDAY EVENING. HOWEVER SEAS
STILL EXPECTED TO BE RELATIVELY HIGH IN THE 4 TO 6 FOOT RANGE.
THEREFORE....SMALL CRAFT ADVISORIES MAY STILL BE NEEDED THROUGH
MUCH OF FRIDAY NIGHT AND POSSIBLY INTO EARLY SATURDAY MORNING.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
LEGRO/JC
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1257 AM EDT THU AUG 8 2013
.SYNOPSIS...
HIGH PRESSURE WILL MOVE SOUTHEAST OF THE AREA OVERNIGHT. A COLD FRONT
WILL APPROACH FROM QUEBEC THURSDAY NIGHT...THEN CROSS THE REGION
FRIDAY WHILE LOW PRESSURE MOVES NORTH ALONG THE FRONT.
&&
.NEAR TERM /THROUGH TODAY/...
1250 AM UPDATE...CLOUDS WILL CONTINUE TO INCREASE OVERNIGHT AND
THE CLOUD COVER WILL KEEP TEMPERATURES FROM FALLING ALL THAT MUCH.
THEREFORE...HAVE RAISED OVERNIGHT LOWS A FEW DEGREES. OTHERWISE
THE FORECAST STILL LOOKS ON TRACK. THE LATEST HRRR AND RUC INDICATE
THAT SHOWERS WILL START TO MAKE IT INTO THE WESTERN ZONES AFTER
06Z AND THE CURRENT GRIDDED DATABASE SEEMS TO HAVE A GOOD HANDLE ON
THIS.
PREVIOUS DISCUSSION
HIGH PRESSURE WILL MOVE EAST OVERNIGHT. CLEAR SKIES AND LIGHT
WINDS WILL ALLOW TEMPERATURES TO FALL INTO THE LOW 50S WITH A FEW
READINGS IN THE UPPER 40S POSSIBLE TOWARDS THE EASTERN BORDER OF
THE STATE. CLOUDS INCREASE THURSDAY AS AN OCCLUDED FRONT
APPROACHES. THIS FRONT IS ASSOCIATED WITH A CUT OFF UPPER LOW IN
WESTERN ONTARIO. A SHORTWAVE ROTATING AROUND THE LOW WILL WEAKEN
AS IT MOVES INTO QUEBEC. AS A RESULT...THE FRONT WILL ALSO WEAKEN
AS IT MOVES INTO THE FORECAST AREA THURSDAY MORNING. BESIDES
INCREASING CLOUDS...SOME SHOWER ACTIVITY IS EXPECTED WITH A TENTH
OR TWO OF AN INCH OF RAIN POSSIBLE. THE SURFACE FRONT IS NOT
EXPECTED TO CROSS THE STATE THURSDAY...BUT MORE HUMID AIR WILL BE
INTRODUCED IN WESTERN PORTIONS OF THE FORECAST AREA THURSDAY
AFTERNOON. THIS HUMID AIR AND SOME PERIODS OF AFTERNOON SUNSHINE
IS EXPECTED TO DESTABILIZE THE ATMOSPHERE AND ALLOW SOME
THUNDERSTORMS TO DEVELOP...MOSTLY FOR PISCATAQUIS COUNTY AND FAR
SOUTHWESTERN PENOBSCOT COUNTY. ELSEWHERE...A COMBINATION OF CLOUD
COVER AND MARINE INFLUENCES SHOULD PREVENT MUCH DAYTIME HEATING
AND INSTABILITY. HIGHS WILL ONLY REACH THE UPPER 60S TO LOW 70S.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM FRIDAY/...
A COLD FRONT WILL APPROACH THURSDAY NIGHT WITH A CHANCE OF SHOWERS
ACROSS THE FORECAST AREA IN ADVANCE OF THE FRONT. THE COLD FRONT
THEN CROSSES THE REGION FRIDAY THROUGH FRIDAY NIGHT WHILE AN AREA
OF LOW PRESSURE MOVES NORTH ALONG THE FRONT. AN AREA OF RAIN WILL
CROSS THE REGION FRIDAY THROUGH EARLY FRIDAY NIGHT...WITH THE
SLIGHT CHANCE OF A THUNDERSTORM FRIDAY AFTERNOON. THE
PRECIPITATION WILL THEN TAPER TO SHOWERS IN THE WAKE OF THE FRONT
LATER FRIDAY NIGHT. THE COLD FRONT WILL MOVE EAST OF THE REGION
EARLY SATURDAY...WHILE AN UPPER LOW TRACKS NORTH OF MAINE SATURDAY
AFTERNOON. COULD HAVE AN ISOLATED SHOWER DOWNEAST EARLY SATURDAY.
OTHERWISE...EXPECT PARTLY/MOSTLY SUNNY SKIES DOWNEAST SATURDAY. A
CHANCE OF SHOWERS COULD EXIST ACROSS NORTHERN AREAS INTO THE
EARLY AFTERNOON SATURDAY WITH THE UPPER LOW. OTHERWISE...EXPECT
PARTLY/MOSTLY CLOUDY SKIES ACROSS NORTHERN AREAS DURING THE
MORNING WITH DECREASING CLOUDS DURING THE AFTERNOON. HIGH PRESSURE
THEN BUILDS ACROSS THE REGION SATURDAY NIGHT. TEMPERATURES WILL BE
AT BELOW NORMAL LEVELS FRIDAY...WITH SLIGHTLY BELOW NORMAL LEVEL
TEMPERATURES SATURDAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
SUNDAY WILL FEATURE MAINLY SUNNY SKIES WITH SEASONAL TEMPERATURES
TO ROUND OUT THE WEEKEND ALONG WITH COMFORTABLY LOW LEVELS OF
HUMIDITY. EXPECT MAINLY CLEAR AND COOL CONDITIONS SUNDAY NIGHT
UNDER HIGH PRESSURE. CLOUDS BEGIN TO INCREASE MONDAY WITH THE
APPROACH OF THE NEXT SYSTEM. THIS SYSTEM WILL BRING A CHANCE OF
SHOWERS ARRIVING BY LATE DAY MONDAY AND LASTING INTO TUESDAY.
CONDITIONS WILL CLEAR OUT ONCE AGAIN FOR THE MIDDLE OF NEXT WEEK.
AT THIS POINT NO MAJOR HOT SPELLS ARE ON THE HORIZON WITH THE
OVERALL PATTERN FAVORING AVERAGE TO BELOW AVERAGE TEMPERATURES.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
NEAR TERM: VFR THROUGH TONIGHT. MVFR CEILINGS ARE EXPECTED TO
DEVELOP THURSDAY MORNING IN SHOWERS.
SHORT TERM: MVFR/IFR...WITH OCCASIONAL LIFR...CONDITIONS ARE
EXPECTED THURSDAY NIGHT INTO EARLY FRIDAY NIGHT. VFR/MVFR
CONDITIONS ARE EXPECTED LATER FRIDAY NIGHT. OCCASIONAL MVFR
CONDITIONS ARE POSSIBLE ACROSS NORTHERN AREAS EARLY SATURDAY.
OTHERWISE...VFR CONDITIONS ARE EXPECTED ACROSS THE REGION SATURDAY
THROUGH SATURDAY NIGHT. EXPECT VFR SUNDAY INTO MONDAY WITH
MVFR/IFR POSSIBLE BY TUESDAY.
&&
.MARINE...
NEAR TERM: WINDS WILL INCREASE THURSDAY WITH GUSTS UP TO 15 KTS
FROM THE SOUTH. SEAS WILL ALSO INCREASE TOWARDS 3 TO 4 FEET BY
LATER THURSDAY.
SHORT TERM: SMALL CRAFT ADVISORY LEVEL SEAS ARE POSSIBLE THURSDAY
NIGHT INTO EARLY SATURDAY. VISIBILITIES COULD BE REDUCED IN RAIN
AND FOG THURSDAY NIGHT INTO FRIDAY NIGHT...WITH A LINGERING
SHOWER POSSIBLE EARLY SATURDAY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DUDA
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
850 PM EDT FRI AUG 9 2013
.SYNOPSIS...
LOW PRESSURE MOVING EAST THROUGH CANADA WILL DRAG A COLD FRONT
SOUTHEAST INTO THE MID ATLANTIC OVERNIGHT. THE FRONT WILL STALL OVER
THE SOUTHERN MID ATLANTIC THIS WEEKEND AND MONDAY BEFORE ANOTHER A
COLD FRONT CROSSES THE REGION TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
CDFNT APPEARS TO BE ACRS NRN MD/ERN WVA ATTM. AMS IN THIS RGN
STBL...EVIDENCED BY PBZ 00Z RAOB...AND EVEN SHRA ALONG THE FNT
HAVING DFCLTY SUSTAINING THEMSELVES. THE FNT ITSELF WL BE
SNEAKING THRU THE CWFA TNGT.
THE MORE AGGRESSIVE ACTIVITY ACRS SRN MD ATTM...INVOF A LEE TROF.
HERE THE COMBO OF 2000 J/KG SBCAPE...30-35 KT EFFECTIVE BULK
SHEAR...AND MID 70S DEWPTS WORKING IN CONCERT W/ THE LLVL FORCING
OF THE TROF AXIS AND BAY BNDRYS HV BEEN ENUF TO OVERCOME POOR
MID-LVL LAPSE RATES. HRRR SUGGESTS THESE STORMS WL CONT PAST
MIDNGT. RDR TRENDS SUGGEST THAT MAY BE A BIT LONG...AND WL STRIKE
A BALANCE IN THE GRIDS.
TRULY DRIER AIR STILL BACK ACRS NWRN PA. DO XPCT SOME TO DRAIN SWD
BY MRNG...BUT IT WL BE A SLOW PROCESS. WHILE MOST OF THE OVNGT HRS
WL BE DRY IN TERMS OF LACK OF RAFL...IT STILL WL BE A BIT HUMID.
THIS POSES THE PATCHY FOG THREAT ONCE AGN.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
MODELS ARE A LITTLE MORE AGGRESSIVE PUSHING THE FRONTAL BOUNDARY
INTO SOUTHERN VIRGINIA ON SATURDAY. AM WORRIED THIS IS A LITTLE TOO
FAR SOUTH TOO SOON AND FORECAST REFLECTS FRONT LOCATED OVER
CENTRAL VIRGINIA ON SATURDAY. THUS...CHANCE POPS IN THIS AREA.
MEANWHILE...GUIDANCE SHOWS SOME DRIER AIR PUSHING SOUTH OF THE
MASON DIXON LINE INTO WESTERN/CENTRAL MARYLAND...EASTERN WEST
VIRGINIA AND NORTHERN VA/DC. IN RESPONSE...HAVE TRIMMED POPS IN
THIS AREA FOR SATURDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
A ZONAL PATTERN WILL SET UP ACROSS THE MID ATLANTIC FOR THE END OF
THE WEEKEND. THE STALLED COLD FRONT SHOULD BE ACROSS THE VA/NC
BORDER AND CONVERGENCE ALONG IT WILL CONTINUE TO PRODUCE SHOWERS AND
THUNDERSTORMS. WEAK NORTHERLY FLOW WILL BRING IN SOME LOWER DEWPT
AIR SUNDAY BUT GFS AND NAM BOTH SHOW THE STALLED FROPA MOVING NORTH
AS A WARM FRONT. PWAT VALUES WILL STILL BE NEAR 1.5IN ACROSS THE
REGION. AS FLOW STAYS ZONAL AND HIGH PRESSURE ALOFT BLOCKS THE
SOUTHWARD PROGRESSION OF FROPA...DEWPTS IN THE LOW 70S AND MARGINAL
LAPSE RATES MAY PRODUCE THUNDERSTORMS MAINLY SOUTH OF I-66 IN
VICINITY OF FROPA SUNDAY AFTERNOON. AN ISOLATED THUNDERSTORM MAY
PRODUCE DAMAGING WIND IN THE AFTERNOON. TEMPS ARE EXPECTED TO REACH
THE MID TO UPPER 80S SUNDAY.
ANOTHER CENTER OF LOW PRESSURE WILL DIP DOWN ACROSS THE HUDSON BAY
AND A COLD FRONT WILL MOVE THROUGH THE GREAT LAKES REGION MONDAY.
THE SLOW MOVING FROPA WILL STAY ACROSS THE SOUTHERN PORTIONS OF LWX
WHILE MULTIPLE DISTURBANCES CROSS THE REGION. E-SE FLOW FORMS
DURING THE DAY AND SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE MAINLY
NEAR THE BLUE RIDGE AND WEST. THE GREAT LAKES FROPA WILL MOVE
ACROSS THE REGION TUESDAY AFTERNOON AND EVENING PER THE GFS AND
ECMWF. PROGRESSION OF THIS FRONT WILL BE QUICKER AS THE UPPER LEVEL
TROUGH SWINGS THROUGH THE EASTERN US. HIGH PRESSURE MOVES INTO THE
REGION TOWARDS THE END OF THE WORK WEEK. SLIGHTLY BELOW NORMAL HIGH
TEMPS WILL CONTINUE THROUGH THE LONG TERM.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
TSTMS NOW SE OF TERMINALS. VFR XPCTD OVNGT OUTSIDE OF PATCHY FOG.
WL BE KEEPING THAT THREAT TO THE W /IAD/CHO/MRB/ AT MVFR LVLS...
BRIEFLY DOWN TO IFR AT CHO.
TEH FNT WL LINGER ACRS CENTRL/SRN VA SAT. CHO MAY REMAIN IN THE
ZONE WHERE SCT TSRA PSBL. ANY RESTRICTIONS WUD BE LMTD AND BRIEF.
ELSW...VFR SHUD REMAIN IN LGT NW FLOW.
A STALLED FRONTAL BOUNDARY WILL PERSIST ACROSS SOUTHERN VA SUNDAY AND
MONDAY. SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE MAINLY FOR CHO.
MVFR/IFR CONDITIONS WILL BE POSSIBLE IN ACTIVITY. A QUICKER FROPA
WILL CROSS THE REGION TUESDAY. HIGH PRESSURE MOVES INTO THE REGION
TOWARDS THE END OF THE WORK WEEK.
&&
.MARINE...
HV ALLOWED SCA TO EXPIRE AT 8PM. THAT/S NOT TO SAY WX THREATS
OVER...AS A LINE OF STRONG TSRA REMAIN ACRS SRN MD...INCL ADJACENT
WATERS. HV SPECIAL MARINE WRNGS IN EFFECT TO COVER THE ASSOCD WND
GUSTS.
LGT W/NW WNDS OVNGT-TMRW. SINCE FNT WL ONLY SLOWLY CLR THE AREA...
GRADIENT NOT XPCTD TO BE TOO STRONG.
A STALLED FRONTAL BOUNDARY WILL PERSIST ACROSS SOUTHERN VA SUNDAY AND
MONDAY. SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE MAINLY FOR THE
SOUTHERN PORTIONS OF THE WATERS. SOME THUNDERSTORMS MAY WARRANT A
SMW OR MWS SUNDAY AFTERNOON AND EVENING. ANOTHER FROPA WILL CROSS
THE WATERS TUESDAY NIGHT.
&&
.TIDES/COASTAL FLOODING...
TIDAL DEPARTURES ON THE BAY AROUND 1/2 TO 3/4 OF A FT ABV NORMAL.
THESE LVLS LOW ENUF SO THAT NO FLOODING HAS TAKEN PLACE WITH THE
EVNG TIDE CYCLE. WNDS OVNGT-SAT WL TURN W/NW...WHICH WL FURTHER
EASE THE SITUATION. THUS...NO ADDTL FLOODING XPCTD ATTM.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
205 PM EDT THU AUG 8 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 518 AM EDT THU AUG 8 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A DEEP MID LEVEL LOW OVER
NRN ONTARIO JUST E OF THE MANITOBA/ONTARIO BORDER. FOR THIS TIME OF
YEAR...THE LOW IS UNUSUALLY DEEP WITH 500MB HEIGHTS 2.5 STANDARD
DEVIATIONS BELOW THE LONG TERM AVG. THE UPPER LAKES ARE UNDER THE
SRN PORTION OF ITS RATHER EXPANSIVE CIRCULATION. IN THE WAKE OF THE
SHORTWAVES THAT PASSED ACROSS THE UPPER LAKES YESTERDAY...A DRY AIR
MASS HAS PUSHED INTO UPPER MI. COMBINED WITH CLEAR SKIES AND
LIGHT/CALM WIND...TEMPS HAVE ONCE AGAIN DIPPED AS LOW AS THE UPPER
30S IN SOME OF THE TRADITIONAL COLD SPOTS IN THE INTERIOR (DOE LAKE
AND SPINCICH LAKE IN PARTICULAR). JUST TO THE W...A SHORTWAVE THAT
WAS MUCH MORE WELL DEFINED YESTERDAY AFTN HAS WEAKENED/SHEARED E
INTO MN...AND IT IS SPREADING A BAND OF MID CLOUDS ACROSS NRN MN AND
WRN LAKE SUPERIOR. AFTER DIMINISHING...A BAND OF SHRA HAS
REDEVELOPED ACROSS NRN MN IN ASSOCIATION WITH THE SHORTWAVE. TO THE
NW OVER MANITOBA...A SHORTWAVE SPOKE IS EVIDENT ROTATING AROUND THE
DEEP MIDLEVEL LOW OVER NRN ONTARIO. BOTH OF THESE SHORTWAVES WILL
HAVE SOME IMPACT ON THE WEATHER HERE TODAY/TONIGHT.
FIRST UP...THE WEAKENING SHORTWAVE OVER MN WILL PASS ACROSS THE AREA
THIS MORNING. SEVERAL OF THE HIGH RES MODELS INCLUDING NAM AND HIGH
RES WRF-ARW/WRF-NMM HAVE DONE A NICE JOB PICKING UP ON THE LOCATION
OF SHRA TO THE W AND SUGGEST SHRA WILL TEND TO DISSIPATE AS THEY
SHIFT E INTO WRN UPPER MI THIS MORNING. WILL GENERALLY FOLLOW THIS
IDEA AND SPREAD ISOLD -SHRA INTO PORTIONS OF WRN UPPER MI THIS
MORNING. DURING THE AFTN...NEXT SHORTWAVE CURRENTLY ROTATING THRU
SRN MANITOBA SHOULD PROVIDE FORCING FOR ISOLD TO PERHAPS SCT AFTN
CONVECTION WITH LAKE BREEZES PROVIDING A LOW LEVEL FOCUS AS WELL.
WITH MLCAPES ONLY UP TO A COUPLE HUNDRED J/KG...THUNDER POTENTIAL IS
MINIMAL...BUT PROBABLY STILL WORTHY OF INCLUDING MENTION IN FCST.
ISOLD/SCT SHRA SHOULD SLOWLY SHIFT E AND SE TONIGHT AS PRONOUNCED
MID LEVEL DRYING PUSHES IN FROM THE W. THIS SHOULD ALSO LEAD TO
CLEARING OVER AT LEAST THE W HALF OR SO OF THE FCST AREA. LEANED
SOMEWHAT TOWARD THE LOWER SIDE OF AVBL GUIDANCE FOR MINS OVER THE W
WITH EXPECATION OF CLEARING AND A DRYING COLUMN.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 518 AM EDT THU AUG 8 2013
OMEGA BLOCKING FROM ALASKA TO EASTERN CANADA WILL FINALLY BEGIN TO
BREAKDOWN...ALBEIT SLOWLY...BY THIS WEEKEND. BESIDE A CHANCE FOR
SHOWERS AND STORMS SUNDAY AFTERNOON INTO MONDAY NIGHT...THE LONG
TERM TREND WILL BE DRY AND SLIGHTLY COOLER THAN NORMAL.
FRIDAY THROUGH SATURDAY NIGHT...A DEEP CLOSED MID-LEVEL LOW OVER
NORTHERN ONTARIO WILL BE SENDING A SHORTWAVE TROUGH ACROSS THE CWA
THURSDAY NIGHT. THE ASSOCIATED COLD FRONT IS PROGGED TO CLEAR THE
CWA BY 12Z FRIDAY...WITH MUCH DRIER AIR USHERING IN BEHIND IT. SOME
LOW-LEVEL MOISTURE COULD LINGER ACROSS THE EAST HALF AFTER 12Z UNDER
INCREASING SUBSIDENCE BEHIND THE FRONT...SO KEPT SLIGHT CHANCE POPS
FOR A FEW HOURS BEYOND 12Z FOR THE FAR EAST.
THE MAIN TROUGH AXIS WILL THEN PUSH SOUTHEASTWARD ACROSS THE CWA
FRIDAY AFTERNOON INTO LATE FRIDAY NIGHT. WHILE MOISTURE IS LACKING
IN THE MID-LEVELS...H8 TO H7 FGEN UNDER MODEST MID-LEVEL
Q-VECTOR CONVERGENCE WILL LEAD TO INCREASED CLOUDINESS BELOW H5. THE
NAM IS THE ONLY MODEL TO INDICATE A SHOT AT ISOLATED SHOWERS ACROSS
THE NORTH CLOSER TO THE MAIN FORCING. HAVE OPTED TO KEEP ANY PRECIP
OUT OF THE FORECAST FOR NOW GIVEN VERY DRY LOW LEVELS AND THAT MOST
MODELS HAVE BEEN CONSISTENT WITH ALL PRECIP REMAINING OUT OF THE
CWA. MODEL TRENDS HAVE ALSO SHOWED A STRONGER PRESSURE
GRADIENT...ESPECIALLY NORTH....WITH THE TROUGH PASSAGE. WEAK
STABILITY SUGGESTS THAT MIXING COULD BRING GUSTY WNW OF UP TO 25 MPH
TO MUCH OF THE NORTH HALF BY THE AFTERNOON.
SFC HIGH PRESSURE WILL THEN BUILD INTO THE UPPER GREAT LAKES WITH
MID-LEVEL SHORTWAVE RIDGING FRIDAY NIGHT THROUGH SATURDAY. GENERALLY
CLEAR SKIES AND LOW PWATS OF AROUND 0.5 INCHES WILL BE CONDUCIVE FOR
GOOD RADIATIONAL COOLING ACROSS MUCH OF THE CWA...PARTICULARLY THE
INTERIOR WEST HALF. HAVE FOLLOWED THE PREVIOUS SHIFTS TREND OF
LOWERING TEMPS. WIDESPREAD 40S ARE LIKELY FOR ALL BUT THE IMMEDIATE
GREAT LAKES SHORELINES. WEAK LOW-LEVEL MOISTURE RETURN WILL BEGIN
ACROSS THE WEST SATURDAY AFTERNOON AS THE SFC HIGH MOVES EAST. WITH
THIS MOISTURE INCREASE...AFTERNOON CUMULUS DEVELOPMENT WILL BE
COMMON. A FEW ISOLATED DIURNAL SHOWERS COULD EVEN BE POSSIBLE...BUT
ONCE AGAIN...CONFIDENCE IS TOO LOW TO INTRODUCE ANY PRECIP ATTM. LOW
TO MID-LEVEL CLOUDINESS WILL CONTINUE TO INCREASE WITH THE MOISTURE
RETURN SATURDAY NIGHT...KEEPING TEMPS SEVERAL DEGREES WARMER THAN
FRIDAY NIGHT.
SUNDAY THROUGH MONDAY...ANOTHER SHORTWAVE TROUGH ON THE BACKSIDE OF
THE DEEP EASTERN CANADIAN MID-LEVEL TROUGH WILL BE DIGGING SOUTHWARD
ACROSS FAR WESTERN ONTARIO LATE SATURDAY NIGHT. THE ECMWF HAS SLOWED
THIS TROUGH PASSAGE OVER THE LAST FEW RUNS...AND NOW LINES UP WELL
WITH THE GFS IN BRINGING THE MAIN TROUGH AXIS THROUGH MONDAY
EVENING. BOTH MODELS HAVE ALSO RECENTLY PICKED UP ON A WEAK LEAD
SHORTWAVE TROUGH FROM PHASING BETWEEN A PORTION OF THE MAIN TROUGH
AND A WEAK WAVE MOVING EASTWARD FROM WESTERN CANADA. THE TIMING OF
THIS WEAK WAVE IS A LITTLE DIFFERENT BETWEEN THE TWO MODELS...WITH
THE CONSENSUS BEING EARLY SUNDAY EVENING. INSTABILITY WILL BE QUITE
POOR NORTH OF THE WI BORDER AND SHOULD PRECLUDE ANY STRONG
THUNDERSTORM THREAT ATTM. THE TROUGH WILL CONTINUE TO SLOWLY WORK
EASTWARD ACROSS THE CWA AND BRING ISOLATED TO SCATTERED SHOWERS
THROUGH MONDAY AFTERNOON.
MONDAY NIGHT THROUGH WEDNESDAY...BY THIS POINT...THE ECMWF AND GFS
HAVE SOME DISAGREEMENT ON THE STRENGTH OF THE SHORTWAVE...AND HOW
QUICK IT WILL DEPART. THE ECMWF IS MUCH QUICKER AND BRINGS GENERALLY
DRY CONDITIONS THROUGH WEDNESDAY. THE GFS SWINGS A STRONG SECONDARY
TROUGH ACROSS THE EASTERN CWA ON TUESDAY...BUT LIMITS SHOWERS TO
ONLY THE EAST HALF. STUCK WITH OVERALL MODEL CONSENSUS FOR
NOW...THROUGH MUCH OF THE PERIOD SHOULD REMAIN DRY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 205 PM EDT THU AUG 8 2013
CONDITIONS ARE EXPECTED TO REMAIN VFR THROUGH THE TAF PERIOD. A WEAK
LOW PRESSURE TROUGH IS CROSSING UPPER MICHIGAN THIS AFTERNOON...AND
HAS LED TO THE DEVELOPMENT OF ISOLATED RAIN SHOWERS ACROSS MAINLY
WESTERN AND FAR NORTH CENTRAL UPPER MICHIGAN. THESE SHOWERS HAVE
BEEN VERY LIGHT...AND ARE EXPECTED TO CONTINUE TO DEVELOP NEAR
KSAW/KCMX/KIWD THROUGH EARLY EVENING. KIWD HAS THE BEST CHANCE
EARLIER ON...AS SHOWERS ARE JUST PASSING BAYFIELD WI. IN HEAVIER
SHOWERS CONDITIONS COULD DROP TO MVFR...HOWEVER NOT CONFIDENT ENOUGH
TO PUT IN THE TAF. HAVE KEPT VCSH IN FOR NOW. TOMORROW AFTERNOON YET
ANOTHER TROUGH WILL MAKE ITS WAY INTO THE U.P. EXCEPT THE AIRMASS IS
MUCH DRIER THAN TODAY. EXPECTING THAT KCMX HAS THE ONLY CHANCE OF
SEEING THESE SHOWERS...AND WAS NOT CONFIDENT ENOUGH TO PLACE IN THE
TAF.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 518 AM EDT THU AUG 8 2013
EXPECT WINDS UNDER 20KT ACROSS LAKE SUPERIOR TODAY/TONIGHT UNDER A
GENERALLY WEAK PRES GRADIENT. HOWEVER...WINDS WILL BEGIN TO INCREASE
OVERNIGHT TONIGHT AHEAD OF THE NEXT COLD FRONT DROPPING SE. AN
INCREASING PRESSURE GRADIENT BETWEEN HIGH PRESSURE BUILDING IN FROM
SOUTH CENTRAL CANADA AND LOW PRESSURE EXITING TO THE EAST ACROSS
EASTERN ONTARIO WILL CREATE W TO WNW WINDS OF 15 TO 25 KNOTS ACROSS
WESTERN LAKE SUPERIOR FRIDAY MORNING...AND CENTRAL AND EASTERN LAKE
SUPERIOR FRIDAY AFTERNOON. WEST WINDS UNDER 15 KNOTS WILL THEN BE THE
RULE THROUGH THE WEEKEND AS THE HIGH PRESSURE SETTLES OVER THE UPPER
GREAT LAKES. ANOTHER TROUGH WILL CROSS LAKE SUPERIOR ON MONDAY AND
BRING NW WINDS UNDER 15 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KLUBER
AVIATION...MCD
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
137 PM EDT THU AUG 8 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 518 AM EDT THU AUG 8 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A DEEP MID LEVEL LOW OVER
NRN ONTARIO JUST E OF THE MANITOBA/ONTARIO BORDER. FOR THIS TIME OF
YEAR...THE LOW IS UNUSUALLY DEEP WITH 500MB HEIGHTS 2.5 STANDARD
DEVIATIONS BELOW THE LONG TERM AVG. THE UPPER LAKES ARE UNDER THE
SRN PORTION OF ITS RATHER EXPANSIVE CIRCULATION. IN THE WAKE OF THE
SHORTWAVES THAT PASSED ACROSS THE UPPER LAKES YESTERDAY...A DRY AIR
MASS HAS PUSHED INTO UPPER MI. COMBINED WITH CLEAR SKIES AND
LIGHT/CALM WIND...TEMPS HAVE ONCE AGAIN DIPPED AS LOW AS THE UPPER
30S IN SOME OF THE TRADITIONAL COLD SPOTS IN THE INTERIOR (DOE LAKE
AND SPINCICH LAKE IN PARTICULAR). JUST TO THE W...A SHORTWAVE THAT
WAS MUCH MORE WELL DEFINED YESTERDAY AFTN HAS WEAKENED/SHEARED E
INTO MN...AND IT IS SPREADING A BAND OF MID CLOUDS ACROSS NRN MN AND
WRN LAKE SUPERIOR. AFTER DIMINISHING...A BAND OF SHRA HAS
REDEVELOPED ACROSS NRN MN IN ASSOCIATION WITH THE SHORTWAVE. TO THE
NW OVER MANITOBA...A SHORTWAVE SPOKE IS EVIDENT ROTATING AROUND THE
DEEP MIDLEVEL LOW OVER NRN ONTARIO. BOTH OF THESE SHORTWAVES WILL
HAVE SOME IMPACT ON THE WEATHER HERE TODAY/TONIGHT.
FIRST UP...THE WEAKENING SHORTWAVE OVER MN WILL PASS ACROSS THE AREA
THIS MORNING. SEVERAL OF THE HIGH RES MODELS INCLUDING NAM AND HIGH
RES WRF-ARW/WRF-NMM HAVE DONE A NICE JOB PICKING UP ON THE LOCATION
OF SHRA TO THE W AND SUGGEST SHRA WILL TEND TO DISSIPATE AS THEY
SHIFT E INTO WRN UPPER MI THIS MORNING. WILL GENERALLY FOLLOW THIS
IDEA AND SPREAD ISOLD -SHRA INTO PORTIONS OF WRN UPPER MI THIS
MORNING. DURING THE AFTN...NEXT SHORTWAVE CURRENTLY ROTATING THRU
SRN MANITOBA SHOULD PROVIDE FORCING FOR ISOLD TO PERHAPS SCT AFTN
CONVECTION WITH LAKE BREEZES PROVIDING A LOW LEVEL FOCUS AS WELL.
WITH MLCAPES ONLY UP TO A COUPLE HUNDRED J/KG...THUNDER POTENTIAL IS
MINIMAL...BUT PROBABLY STILL WORTHY OF INCLUDING MENTION IN FCST.
ISOLD/SCT SHRA SHOULD SLOWLY SHIFT E AND SE TONIGHT AS PRONOUNCED
MID LEVEL DRYING PUSHES IN FROM THE W. THIS SHOULD ALSO LEAD TO
CLEARING OVER AT LEAST THE W HALF OR SO OF THE FCST AREA. LEANED
SOMEWHAT TOWARD THE LOWER SIDE OF AVBL GUIDANCE FOR MINS OVER THE W
WITH EXPECATION OF CLEARING AND A DRYING COLUMN.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 518 AM EDT THU AUG 8 2013
OMEGA BLOCKING FROM ALASKA TO EASTERN CANADA WILL FINALLY BEGIN TO
BREAKDOWN...ALBEIT SLOWLY...BY THIS WEEKEND. BESIDE A CHANCE FOR
SHOWERS AND STORMS SUNDAY AFTERNOON INTO MONDAY NIGHT...THE LONG
TERM TREND WILL BE DRY AND SLIGHTLY COOLER THAN NORMAL.
FRIDAY THROUGH SATURDAY NIGHT...A DEEP CLOSED MID-LEVEL LOW OVER
NORTHERN ONTARIO WILL BE SENDING A SHORTWAVE TROUGH ACROSS THE CWA
THURSDAY NIGHT. THE ASSOCIATED COLD FRONT IS PROGGED TO CLEAR THE
CWA BY 12Z FRIDAY...WITH MUCH DRIER AIR USHERING IN BEHIND IT. SOME
LOW-LEVEL MOISTURE COULD LINGER ACROSS THE EAST HALF AFTER 12Z UNDER
INCREASING SUBSIDENCE BEHIND THE FRONT...SO KEPT SLIGHT CHANCE POPS
FOR A FEW HOURS BEYOND 12Z FOR THE FAR EAST.
THE MAIN TROUGH AXIS WILL THEN PUSH SOUTHEASTWARD ACROSS THE CWA
FRIDAY AFTERNOON INTO LATE FRIDAY NIGHT. WHILE MOISTURE IS LACKING
IN THE MID-LEVELS...H8 TO H7 FGEN UNDER MODEST MID-LEVEL
Q-VECTOR CONVERGENCE WILL LEAD TO INCREASED CLOUDINESS BELOW H5. THE
NAM IS THE ONLY MODEL TO INDICATE A SHOT AT ISOLATED SHOWERS ACROSS
THE NORTH CLOSER TO THE MAIN FORCING. HAVE OPTED TO KEEP ANY PRECIP
OUT OF THE FORECAST FOR NOW GIVEN VERY DRY LOW LEVELS AND THAT MOST
MODELS HAVE BEEN CONSISTENT WITH ALL PRECIP REMAINING OUT OF THE
CWA. MODEL TRENDS HAVE ALSO SHOWED A STRONGER PRESSURE
GRADIENT...ESPECIALLY NORTH....WITH THE TROUGH PASSAGE. WEAK
STABILITY SUGGESTS THAT MIXING COULD BRING GUSTY WNW OF UP TO 25 MPH
TO MUCH OF THE NORTH HALF BY THE AFTERNOON.
SFC HIGH PRESSURE WILL THEN BUILD INTO THE UPPER GREAT LAKES WITH
MID-LEVEL SHORTWAVE RIDGING FRIDAY NIGHT THROUGH SATURDAY. GENERALLY
CLEAR SKIES AND LOW PWATS OF AROUND 0.5 INCHES WILL BE CONDUCIVE FOR
GOOD RADIATIONAL COOLING ACROSS MUCH OF THE CWA...PARTICULARLY THE
INTERIOR WEST HALF. HAVE FOLLOWED THE PREVIOUS SHIFTS TREND OF
LOWERING TEMPS. WIDESPREAD 40S ARE LIKELY FOR ALL BUT THE IMMEDIATE
GREAT LAKES SHORELINES. WEAK LOW-LEVEL MOISTURE RETURN WILL BEGIN
ACROSS THE WEST SATURDAY AFTERNOON AS THE SFC HIGH MOVES EAST. WITH
THIS MOISTURE INCREASE...AFTERNOON CUMULUS DEVELOPMENT WILL BE
COMMON. A FEW ISOLATED DIURNAL SHOWERS COULD EVEN BE POSSIBLE...BUT
ONCE AGAIN...CONFIDENCE IS TOO LOW TO INTRODUCE ANY PRECIP ATTM. LOW
TO MID-LEVEL CLOUDINESS WILL CONTINUE TO INCREASE WITH THE MOISTURE
RETURN SATURDAY NIGHT...KEEPING TEMPS SEVERAL DEGREES WARMER THAN
FRIDAY NIGHT.
SUNDAY THROUGH MONDAY...ANOTHER SHORTWAVE TROUGH ON THE BACKSIDE OF
THE DEEP EASTERN CANADIAN MID-LEVEL TROUGH WILL BE DIGGING SOUTHWARD
ACROSS FAR WESTERN ONTARIO LATE SATURDAY NIGHT. THE ECMWF HAS SLOWED
THIS TROUGH PASSAGE OVER THE LAST FEW RUNS...AND NOW LINES UP WELL
WITH THE GFS IN BRINGING THE MAIN TROUGH AXIS THROUGH MONDAY
EVENING. BOTH MODELS HAVE ALSO RECENTLY PICKED UP ON A WEAK LEAD
SHORTWAVE TROUGH FROM PHASING BETWEEN A PORTION OF THE MAIN TROUGH
AND A WEAK WAVE MOVING EASTWARD FROM WESTERN CANADA. THE TIMING OF
THIS WEAK WAVE IS A LITTLE DIFFERENT BETWEEN THE TWO MODELS...WITH
THE CONSENSUS BEING EARLY SUNDAY EVENING. INSTABILITY WILL BE QUITE
POOR NORTH OF THE WI BORDER AND SHOULD PRECLUDE ANY STRONG
THUNDERSTORM THREAT ATTM. THE TROUGH WILL CONTINUE TO SLOWLY WORK
EASTWARD ACROSS THE CWA AND BRING ISOLATED TO SCATTERED SHOWERS
THROUGH MONDAY AFTERNOON.
MONDAY NIGHT THROUGH WEDNESDAY...BY THIS POINT...THE ECMWF AND GFS
HAVE SOME DISAGREEMENT ON THE STRENGTH OF THE SHORTWAVE...AND HOW
QUICK IT WILL DEPART. THE ECMWF IS MUCH QUICKER AND BRINGS GENERALLY
DRY CONDITIONS THROUGH WEDNESDAY. THE GFS SWINGS A STRONG SECONDARY
TROUGH ACROSS THE EASTERN CWA ON TUESDAY...BUT LIMITS SHOWERS TO
ONLY THE EAST HALF. STUCK WITH OVERALL MODEL CONSENSUS FOR
NOW...THROUGH MUCH OF THE PERIOD SHOULD REMAIN DRY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 136 PM EDT THU AUG 8 2013
CONDITIONS ARE EXPECTED TO REMAIN VFR THROUGH THE TAF PERIOD. A WEAK
LOW PRESSURE TROUGH IS CROSSING UPPER MICHIGAN THIS AFTERNOON...AND
HAS LED TO THE DEVELOPMENT OF ISOLATED RAIN SHOWERS ACROSS MAINLY
WESTERN AND FAR NORTH CENTRAL UPPER MICHIGAN. THESE SHOWERS HAVE
BEEN VERY LIGHT...AND ARE EXPECTED TO CONTINUE TO DEVELOP NEAR
MAINLY KSAW/KCMX THROUGH EARLY EVENING. IN HEAVIER SHOWERS
CONDITIONS COULD DROP TO MVFR...HOWEVER NOT CONFIDENT ENOUGH TO PUT
IN THE TAF. TOMORROW AFTERNOON YET ANOTHER TROUGH WILL MAKE ITS WAY
INTO THE U.P. EXCEPT THE AIRMASS IS MUCH DRIER THAN TODAY. EXPECTING
THAT KCMX HAS THE ONLY CHANCE OF SEEING THESE SHOWERS...AND WAS NOT
CONFIDENT ENOUGH TO PLACE IN THE TAF.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 518 AM EDT THU AUG 8 2013
EXPECT WINDS UNDER 20KT ACROSS LAKE SUPERIOR TODAY/TONIGHT UNDER A
GENERALLY WEAK PRES GRADIENT. HOWEVER...WINDS WILL BEGIN TO INCREASE
OVERNIGHT TONIGHT AHEAD OF THE NEXT COLD FRONT DROPPING SE. AN
INCREASING PRESSURE GRADIENT BETWEEN HIGH PRESSURE BUILDING IN FROM
SOUTH CENTRAL CANADA AND LOW PRESSURE EXITING TO THE EAST ACROSS
EASTERN ONTARIO WILL CREATE W TO WNW WINDS OF 15 TO 25 KNOTS ACROSS
WESTERN LAKE SUPERIOR FRIDAY MORNING...AND CENTRAL AND EASTERN LAKE
SUPERIOR FRIDAY AFTERNOON. WEST WINDS UNDER 15 KNOTS WILL THEN BE THE
RULE THROUGH THE WEEKEND AS THE HIGH PRESSURE SETTLES OVER THE UPPER
GREAT LAKES. ANOTHER TROUGH WILL CROSS LAKE SUPERIOR ON MONDAY AND
BRING NW WINDS UNDER 15 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KLUBER
AVIATION...MCD
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
725 AM EDT THU AUG 8 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 518 AM EDT THU AUG 8 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A DEEP MID LEVEL LOW OVER
NRN ONTARIO JUST E OF THE MANITOBA/ONTARIO BORDER. FOR THIS TIME OF
YEAR...THE LOW IS UNUSUALLY DEEP WITH 500MB HEIGHTS 2.5 STANDARD
DEVIATIONS BELOW THE LONG TERM AVG. THE UPPER LAKES ARE UNDER THE
SRN PORTION OF ITS RATHER EXPANSIVE CIRCULATION. IN THE WAKE OF THE
SHORTWAVES THAT PASSED ACROSS THE UPPER LAKES YESTERDAY...A DRY AIR
MASS HAS PUSHED INTO UPPER MI. COMBINED WITH CLEAR SKIES AND
LIGHT/CALM WIND...TEMPS HAVE ONCE AGAIN DIPPED AS LOW AS THE UPPER
30S IN SOME OF THE TRADITIONAL COLD SPOTS IN THE INTERIOR (DOE LAKE
AND SPINCICH LAKE IN PARTICULAR). JUST TO THE W...A SHORTWAVE THAT
WAS MUCH MORE WELL DEFINED YESTERDAY AFTN HAS WEAKENED/SHEARED E
INTO MN...AND IT IS SPREADING A BAND OF MID CLOUDS ACROSS NRN MN AND
WRN LAKE SUPERIOR. AFTER DIMINISHING...A BAND OF SHRA HAS
REDEVELOPED ACROSS NRN MN IN ASSOCIATION WITH THE SHORTWAVE. TO THE
NW OVER MANITOBA...A SHORTWAVE SPOKE IS EVIDENT ROTATING AROUND THE
DEEP MIDLEVEL LOW OVER NRN ONTARIO. BOTH OF THESE SHORTWAVES WILL
HAVE SOME IMPACT ON THE WEATHER HERE TODAY/TONIGHT.
FIRST UP...THE WEAKENING SHORTWAVE OVER MN WILL PASS ACROSS THE AREA
THIS MORNING. SEVERAL OF THE HIGH RES MODELS INCLUDING NAM AND HIGH
RES WRF-ARW/WRF-NMM HAVE DONE A NICE JOB PICKING UP ON THE LOCATION
OF SHRA TO THE W AND SUGGEST SHRA WILL TEND TO DISSIPATE AS THEY
SHIFT E INTO WRN UPPER MI THIS MORNING. WILL GENERALLY FOLLOW THIS
IDEA AND SPREAD ISOLD -SHRA INTO PORTIONS OF WRN UPPER MI THIS
MORNING. DURING THE AFTN...NEXT SHORTWAVE CURRENTLY ROTATING THRU
SRN MANITOBA SHOULD PROVIDE FORCING FOR ISOLD TO PERHAPS SCT AFTN
CONVECTION WITH LAKE BREEZES PROVIDING A LOW LEVEL FOCUS AS WELL.
WITH MLCAPES ONLY UP TO A COUPLE HUNDRED J/KG...THUNDER POTENTIAL IS
MINIMAL...BUT PROBABLY STILL WORTHY OF INCLUDING MENTION IN FCST.
ISOLD/SCT SHRA SHOULD SLOWLY SHIFT E AND SE TONIGHT AS PRONOUNCED
MID LEVEL DRYING PUSHES IN FROM THE W. THIS SHOULD ALSO LEAD TO
CLEARING OVER AT LEAST THE W HALF OR SO OF THE FCST AREA. LEANED
SOMEWHAT TOWARD THE LOWER SIDE OF AVBL GUIDANCE FOR MINS OVER THE W
WITH EXPECATION OF CLEARING AND A DRYING COLUMN.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 518 AM EDT THU AUG 8 2013
OMEGA BLOCKING FROM ALASKA TO EASTERN CANADA WILL FINALLY BEGIN TO
BREAKDOWN...ALBEIT SLOWLY...BY THIS WEEKEND. BESIDE A CHANCE FOR
SHOWERS AND STORMS SUNDAY AFTERNOON INTO MONDAY NIGHT...THE LONG
TERM TREND WILL BE DRY AND SLIGHTLY COOLER THAN NORMAL.
FRIDAY THROUGH SATURDAY NIGHT...A DEEP CLOSED MID-LEVEL LOW OVER
NORTHERN ONTARIO WILL BE SENDING A SHORTWAVE TROUGH ACROSS THE CWA
THURSDAY NIGHT. THE ASSOCIATED COLD FRONT IS PROGGED TO CLEAR THE
CWA BY 12Z FRIDAY...WITH MUCH DRIER AIR USHERING IN BEHIND IT. SOME
LOW-LEVEL MOISTURE COULD LINGER ACROSS THE EAST HALF AFTER 12Z UNDER
INCREASING SUBSIDENCE BEHIND THE FRONT...SO KEPT SLIGHT CHANCE POPS
FOR A FEW HOURS BEYOND 12Z FOR THE FAR EAST.
THE MAIN TROUGH AXIS WILL THEN PUSH SOUTHEASTWARD ACROSS THE CWA
FRIDAY AFTERNOON INTO LATE FRIDAY NIGHT. WHILE MOISTURE IS LACKING
IN THE MID-LEVELS...H8 TO H7 FGEN UNDER MODEST MID-LEVEL
Q-VECTOR CONVERGENCE WILL LEAD TO INCREASED CLOUDINESS BELOW H5. THE
NAM IS THE ONLY MODEL TO INDICATE A SHOT AT ISOLATED SHOWERS ACROSS
THE NORTH CLOSER TO THE MAIN FORCING. HAVE OPTED TO KEEP ANY PRECIP
OUT OF THE FORECAST FOR NOW GIVEN VERY DRY LOW LEVELS AND THAT MOST
MODELS HAVE BEEN CONSISTENT WITH ALL PRECIP REMAINING OUT OF THE
CWA. MODEL TRENDS HAVE ALSO SHOWED A STRONGER PRESSURE
GRADIENT...ESPECIALLY NORTH....WITH THE TROUGH PASSAGE. WEAK
STABILITY SUGGESTS THAT MIXING COULD BRING GUSTY WNW OF UP TO 25 MPH
TO MUCH OF THE NORTH HALF BY THE AFTERNOON.
SFC HIGH PRESSURE WILL THEN BUILD INTO THE UPPER GREAT LAKES WITH
MID-LEVEL SHORTWAVE RIDGING FRIDAY NIGHT THROUGH SATURDAY. GENERALLY
CLEAR SKIES AND LOW PWATS OF AROUND 0.5 INCHES WILL BE CONDUCIVE FOR
GOOD RADIATIONAL COOLING ACROSS MUCH OF THE CWA...PARTICULARLY THE
INTERIOR WEST HALF. HAVE FOLLOWED THE PREVIOUS SHIFTS TREND OF
LOWERING TEMPS. WIDESPREAD 40S ARE LIKELY FOR ALL BUT THE IMMEDIATE
GREAT LAKES SHORELINES. WEAK LOW-LEVEL MOISTURE RETURN WILL BEGIN
ACROSS THE WEST SATURDAY AFTERNOON AS THE SFC HIGH MOVES EAST. WITH
THIS MOISTURE INCREASE...AFTERNOON CUMULUS DEVELOPMENT WILL BE
COMMON. A FEW ISOLATED DIURNAL SHOWERS COULD EVEN BE POSSIBLE...BUT
ONCE AGAIN...CONFIDENCE IS TOO LOW TO INTRODUCE ANY PRECIP ATTM. LOW
TO MID-LEVEL CLOUDINESS WILL CONTINUE TO INCREASE WITH THE MOISTURE
RETURN SATURDAY NIGHT...KEEPING TEMPS SEVERAL DEGREES WARMER THAN
FRIDAY NIGHT.
SUNDAY THROUGH MONDAY...ANOTHER SHORTWAVE TROUGH ON THE BACKSIDE OF
THE DEEP EASTERN CANADIAN MID-LEVEL TROUGH WILL BE DIGGING SOUTHWARD
ACROSS FAR WESTERN ONTARIO LATE SATURDAY NIGHT. THE ECMWF HAS SLOWED
THIS TROUGH PASSAGE OVER THE LAST FEW RUNS...AND NOW LINES UP WELL
WITH THE GFS IN BRINGING THE MAIN TROUGH AXIS THROUGH MONDAY
EVENING. BOTH MODELS HAVE ALSO RECENTLY PICKED UP ON A WEAK LEAD
SHORTWAVE TROUGH FROM PHASING BETWEEN A PORTION OF THE MAIN TROUGH
AND A WEAK WAVE MOVING EASTWARD FROM WESTERN CANADA. THE TIMING OF
THIS WEAK WAVE IS A LITTLE DIFFERENT BETWEEN THE TWO MODELS...WITH
THE CONSENSUS BEING EARLY SUNDAY EVENING. INSTABILITY WILL BE QUITE
POOR NORTH OF THE WI BORDER AND SHOULD PRECLUDE ANY STRONG
THUNDERSTORM THREAT ATTM. THE TROUGH WILL CONTINUE TO SLOWLY WORK
EASTWARD ACROSS THE CWA AND BRING ISOLATED TO SCATTERED SHOWERS
THROUGH MONDAY AFTERNOON.
MONDAY NIGHT THROUGH WEDNESDAY...BY THIS POINT...THE ECMWF AND GFS
HAVE SOME DISAGREEMENT ON THE STRENGTH OF THE SHORTWAVE...AND HOW
QUICK IT WILL DEPART. THE ECMWF IS MUCH QUICKER AND BRINGS GENERALLY
DRY CONDITIONS THROUGH WEDNESDAY. THE GFS SWINGS A STRONG SECONDARY
TROUGH ACROSS THE EASTERN CWA ON TUESDAY...BUT LIMITS SHOWERS TO
ONLY THE EAST HALF. STUCK WITH OVERALL MODEL CONSENSUS FOR
NOW...THROUGH MUCH OF THE PERIOD SHOULD REMAIN DRY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 724 AM EDT THU AUG 8 2013
VFR CONDITIONS WILL PERSIST THRU THIS FCST PERIOD AT KIWD/KCMX/KSAW
AS AIR MASS REMAINS DRY IN THE LOW-LEVELS. A COUPLE OF DISTURBANCES
WILL BRING THE POTENTIAL FOR A FEW -SHRA...FIRST OVER WRN UPPER MI
THIS MORNING AND THEN MAINLY OVER CNTRL UPPER MI THIS AFTN/EVENING.
PER RADAR TRENDS...IT APPEARS THAT IF -SHRA/SPRINKLES CURRENTLY OVER
WRN LAKE SUPERIOR HOLD TOGETHER...THEY WILL PASS BTWN KIWD/KCMX THIS
MORNING. EVEN IF PCPN REACHES EITHER TERMINAL...CONDITIONS WILL
REMAIN VFR. CONFIDENCE IN PLACEMENT/COVERAGE OF ANY AFTN -SHRA IN
CNTRL UPPER MI IS TOO LOW RIGHT NOW TO WARRANT ANYTHING MORE THAN A
MENTION OF VCSH AT KSAW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 518 AM EDT THU AUG 8 2013
EXPECT WINDS UNDER 20KT ACROSS LAKE SUPERIOR TODAY/TONIGHT UNDER A
GENERALLY WEAK PRES GRADIENT. HOWEVER...WINDS WILL BEGIN TO INCREASE
OVERNIGHT TONIGHT AHEAD OF THE NEXT COLD FRONT DROPPING SE. AN
INCREASING PRESSURE GRADIENT BETWEEN HIGH PRESSURE BUILDING IN FROM
SOUTH CENTRAL CANADA AND LOW PRESSURE EXITING TO THE EAST ACROSS
EASTERN ONTARIO WILL CREATE W TO WNW WINDS OF 15 TO 25 KNOTS ACROSS
WESTERN LAKE SUPERIOR FRIDAY MORNING...AND CENTRAL AND EASTERN LAKE
SUPERIOR FRIDAY AFTERNOON. WEST WINDS UNDER 15 KNOTS WILL THEN BE THE
RULE THROUGH THE WEEKEND AS THE HIGH PRESSURE SETTLES OVER THE UPPER
GREAT LAKES. ANOTHER TROUGH WILL CROSS LAKE SUPERIOR ON MONDAY AND
BRING NW WINDS UNDER 15 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KLUBER
AVIATION...ROLFSON
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
525 AM EDT THU AUG 8 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 518 AM EDT THU AUG 8 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A DEEP MID LEVEL LOW OVER
NRN ONTARIO JUST E OF THE MANITOBA/ONTARIO BORDER. FOR THIS TIME OF
YEAR...THE LOW IS UNUSUALLY DEEP WITH 500MB HEIGHTS 2.5 STANDARD
DEVIATIONS BELOW THE LONG TERM AVG. THE UPPER LAKES ARE UNDER THE
SRN PORTION OF ITS RATHER EXPANSIVE CIRCULATION. IN THE WAKE OF THE
SHORTWAVES THAT PASSED ACROSS THE UPPER LAKES YESTERDAY...A DRY AIR
MASS HAS PUSHED INTO UPPER MI. COMBINED WITH CLEAR SKIES AND
LIGHT/CALM WIND...TEMPS HAVE ONCE AGAIN DIPPED AS LOW AS THE UPPER
30S IN SOME OF THE TRADITIONAL COLD SPOTS IN THE INTERIOR (DOE LAKE
AND SPINCICH LAKE IN PARTICULAR). JUST TO THE W...A SHORTWAVE THAT
WAS MUCH MORE WELL DEFINED YESTERDAY AFTN HAS WEAKENED/SHEARED E
INTO MN...AND IT IS SPREADING A BAND OF MID CLOUDS ACROSS NRN MN AND
WRN LAKE SUPERIOR. AFTER DIMINISHING...A BAND OF SHRA HAS
REDEVELOPED ACROSS NRN MN IN ASSOCIATION WITH THE SHORTWAVE. TO THE
NW OVER MANITOBA...A SHORTWAVE SPOKE IS EVIDENT ROTATING AROUND THE
DEEP MIDLEVEL LOW OVER NRN ONTARIO. BOTH OF THESE SHORTWAVES WILL
HAVE SOME IMPACT ON THE WEATHER HERE TODAY/TONIGHT.
FIRST UP...THE WEAKENING SHORTWAVE OVER MN WILL PASS ACROSS THE AREA
THIS MORNING. SEVERAL OF THE HIGH RES MODELS INCLUDING NAM AND HIGH
RES WRF-ARW/WRF-NMM HAVE DONE A NICE JOB PICKING UP ON THE LOCATION
OF SHRA TO THE W AND SUGGEST SHRA WILL TEND TO DISSIPATE AS THEY
SHIFT E INTO WRN UPPER MI THIS MORNING. WILL GENERALLY FOLLOW THIS
IDEA AND SPREAD ISOLD -SHRA INTO PORTIONS OF WRN UPPER MI THIS
MORNING. DURING THE AFTN...NEXT SHORTWAVE CURRENTLY ROTATING THRU
SRN MANITOBA SHOULD PROVIDE FORCING FOR ISOLD TO PERHAPS SCT AFTN
CONVECTION WITH LAKE BREEZES PROVIDING A LOW LEVEL FOCUS AS WELL.
WITH MLCAPES ONLY UP TO A COUPLE HUNDRED J/KG...THUNDER POTENTIAL IS
MINIMAL...BUT PROBABLY STILL WORTHY OF INCLUDING MENTION IN FCST.
ISOLD/SCT SHRA SHOULD SLOWLY SHIFT E AND SE TONIGHT AS PRONOUNCED
MID LEVEL DRYING PUSHES IN FROM THE W. THIS SHOULD ALSO LEAD TO
CLEARING OVER AT LEAST THE W HALF OR SO OF THE FCST AREA. LEANED
SOMEWHAT TOWARD THE LOWER SIDE OF AVBL GUIDANCE FOR MINS OVER THE W
WITH EXPECATION OF CLEARING AND A DRYING COLUMN.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 518 AM EDT THU AUG 8 2013
OMEGA BLOCKING FROM ALASKA TO EASTERN CANADA WILL FINALLY BEGIN TO
BREAKDOWN...ALBEIT SLOWLY...BY THIS WEEKEND. BESIDE A CHANCE FOR
SHOWERS AND STORMS SUNDAY AFTERNOON INTO MONDAY NIGHT...THE LONG
TERM TREND WILL BE DRY AND SLIGHTLY COOLER THAN NORMAL.
FRIDAY THROUGH SATURDAY NIGHT...A DEEP CLOSED MID-LEVEL LOW OVER
NORTHERN ONTARIO WILL BE SENDING A SHORTWAVE TROUGH ACROSS THE CWA
THURSDAY NIGHT. THE ASSOCIATED COLD FRONT IS PROGGED TO CLEAR THE
CWA BY 12Z FRIDAY...WITH MUCH DRIER AIR USHERING IN BEHIND IT. SOME
LOW-LEVEL MOISTURE COULD LINGER ACROSS THE EAST HALF AFTER 12Z UNDER
INCREASING SUBSIDENCE BEHIND THE FRONT...SO KEPT SLIGHT CHANCE POPS
FOR A FEW HOURS BEYOND 12Z FOR THE FAR EAST.
THE MAIN TROUGH AXIS WILL THEN PUSH SOUTHEASTWARD ACROSS THE CWA
FRIDAY AFTERNOON INTO LATE FRIDAY NIGHT. WHILE MOISTURE IS LACKING
IN THE MID-LEVELS...H8 TO H7 FGEN UNDER MODEST MID-LEVEL
Q-VECTOR CONVERGENCE WILL LEAD TO INCREASED CLOUDINESS BELOW H5. THE
NAM IS THE ONLY MODEL TO INDICATE A SHOT AT ISOLATED SHOWERS ACROSS
THE NORTH CLOSER TO THE MAIN FORCING. HAVE OPTED TO KEEP ANY PRECIP
OUT OF THE FORECAST FOR NOW GIVEN VERY DRY LOW LEVELS AND THAT MOST
MODELS HAVE BEEN CONSISTENT WITH ALL PRECIP REMAINING OUT OF THE
CWA. MODEL TRENDS HAVE ALSO SHOWED A STRONGER PRESSURE
GRADIENT...ESPECIALLY NORTH....WITH THE TROUGH PASSAGE. WEAK
STABILITY SUGGESTS THAT MIXING COULD BRING GUSTY WNW OF UP TO 25 MPH
TO MUCH OF THE NORTH HALF BY THE AFTERNOON.
SFC HIGH PRESSURE WILL THEN BUILD INTO THE UPPER GREAT LAKES WITH
MID-LEVEL SHORTWAVE RIDGING FRIDAY NIGHT THROUGH SATURDAY. GENERALLY
CLEAR SKIES AND LOW PWATS OF AROUND 0.5 INCHES WILL BE CONDUCIVE FOR
GOOD RADIATIONAL COOLING ACROSS MUCH OF THE CWA...PARTICULARLY THE
INTERIOR WEST HALF. HAVE FOLLOWED THE PREVIOUS SHIFTS TREND OF
LOWERING TEMPS. WIDESPREAD 40S ARE LIKELY FOR ALL BUT THE IMMEDIATE
GREAT LAKES SHORELINES. WEAK LOW-LEVEL MOISTURE RETURN WILL BEGIN
ACROSS THE WEST SATURDAY AFTERNOON AS THE SFC HIGH MOVES EAST. WITH
THIS MOISTURE INCREASE...AFTERNOON CUMULUS DEVELOPMENT WILL BE
COMMON. A FEW ISOLATED DIURNAL SHOWERS COULD EVEN BE POSSIBLE...BUT
ONCE AGAIN...CONFIDENCE IS TOO LOW TO INTRODUCE ANY PRECIP ATTM. LOW
TO MID-LEVEL CLOUDINESS WILL CONTINUE TO INCREASE WITH THE MOISTURE
RETURN SATURDAY NIGHT...KEEPING TEMPS SEVERAL DEGREES WARMER THAN
FRIDAY NIGHT.
SUNDAY THROUGH MONDAY...ANOTHER SHORTWAVE TROUGH ON THE BACKSIDE OF
THE DEEP EASTERN CANADIAN MID-LEVEL TROUGH WILL BE DIGGING SOUTHWARD
ACROSS FAR WESTERN ONTARIO LATE SATURDAY NIGHT. THE ECMWF HAS SLOWED
THIS TROUGH PASSAGE OVER THE LAST FEW RUNS...AND NOW LINES UP WELL
WITH THE GFS IN BRINGING THE MAIN TROUGH AXIS THROUGH MONDAY
EVENING. BOTH MODELS HAVE ALSO RECENTLY PICKED UP ON A WEAK LEAD
SHORTWAVE TROUGH FROM PHASING BETWEEN A PORTION OF THE MAIN TROUGH
AND A WEAK WAVE MOVING EASTWARD FROM WESTERN CANADA. THE TIMING OF
THIS WEAK WAVE IS A LITTLE DIFFERENT BETWEEN THE TWO MODELS...WITH
THE CONSENSUS BEING EARLY SUNDAY EVENING. INSTABILITY WILL BE QUITE
POOR NORTH OF THE WI BORDER AND SHOULD PRECLUDE ANY STRONG
THUNDERSTORM THREAT ATTM. THE TROUGH WILL CONTINUE TO SLOWLY WORK
EASTWARD ACROSS THE CWA AND BRING ISOLATED TO SCATTERED SHOWERS
THROUGH MONDAY AFTERNOON.
MONDAY NIGHT THROUGH WEDNESDAY...BY THIS POINT...THE ECMWF AND GFS
HAVE SOME DISAGREEMENT ON THE STRENGTH OF THE SHORTWAVE...AND HOW
QUICK IT WILL DEPART. THE ECMWF IS MUCH QUICKER AND BRINGS GENERALLY
DRY CONDITIONS THROUGH WEDNESDAY. THE GFS SWINGS A STRONG SECONDARY
TROUGH ACROSS THE EASTERN CWA ON TUESDAY...BUT LIMITS SHOWERS TO
ONLY THE EAST HALF. STUCK WITH OVERALL MODEL CONSENSUS FOR
NOW...THROUGH MUCH OF THE PERIOD SHOULD REMAIN DRY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 144 AM EDT THU AUG 8 2013
VFR CONDITIONS WILL PERSIST THRU THE END OF THIS FCST PERIOD AT
KIWD/KCMX/KSAW. LAKE BREEZES WILL MOVE INTO KSAW LATER IN THE
AFTERNOON. PCPN CHANCE IS TOO LOW AT THIS POINT TO PUT INTO THE TAFS
AS NEXT UPPER LEVEL DISTURBANCE PASSES THROUGH TODAY.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 518 AM EDT THU AUG 8 2013
EXPECT WINDS UNDER 20KT ACROSS LAKE SUPERIOR TODAY/TONIGHT UNDER A
GENERALLY WEAK PRES GRADIENT. HOWEVER...WINDS WILL BEGIN TO INCREASE
OVERNIGHT TONIGHT AHEAD OF THE NEXT COLD FRONT DROPPING SE. AN
INCREASING PRESSURE GRADIENT BETWEEN HIGH PRESSURE BUILDING IN FROM
SOUTH CENTRAL CANADA AND LOW PRESSURE EXITING TO THE EAST ACROSS
EASTERN ONTARIO WILL CREATE W TO WNW WINDS OF 15 TO 25 KNOTS ACROSS
WESTERN LAKE SUPERIOR FRIDAY MORNING...AND CENTRAL AND EASTERN LAKE
SUPERIOR FRIDAY AFTERNOON. WEST WINDS UNDER 15 KNOTS WILL THEN BE THE
RULE THROUGH THE WEEKEND AS THE HIGH PRESSURE SETTLES OVER THE UPPER
GREAT LAKES. ANOTHER TROUGH WILL CROSS LAKE SUPERIOR ON MONDAY AND
BRING NW WINDS UNDER 15 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KLUBER
AVIATION...07
MARINE...ROLFSON
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
935 PM CDT Fri Aug 9 2013
.UPDATE:
Issued at 935 PM CDT Fri Aug 9 2013
The highly unusual August pattern continues.
A weak cold front has since pushed further into central IL and
about halfway between KUIN and KSTL in MO. As a result, the old
line of SHRA/TSRA has dissipated, but it has helped to give more
form to the sprinkles that have been moving through the area, and
has resulted in isolated SHRA in parts of SW IL. This feature is
essentially going to merge with the upper level disturbance now
moving through east- central MO, where the SHRA there has all but
faded after sunset. Look for a continued low threat for SHRA into
the overnight between this upper level disturbance moving through
and the weak cold front that will primarily be focused on the IL
side of the MS river.
If clouds exit faster than anticipated, the low temp-dewpoint
spreads may result in another night of patchy fog. Current
indications are they will linger for much of the night, though.
Just south of the forecast area, an old frontal boundary exists
and has been the main focus for waves of rain for the past several
nights on the cool side. The next 24 hours will probably not be
much different, with another wave of SHRA/TSRA expected to move
into SE MO Saturday morning, the difference expected to be the
trend for rain further and further south with each day.
Temps look to be in the ballpark for mins in the 60s.
TES
&&
.SHORT TERM: (Through Late Tonight)
Issued at 317 PM CDT Fri Aug 9 2013
Area of rain extending from central Missouri into southwest Illinois
has persisted on the north side of a side of MCV that is currently
tracking through southeast Missouri. This rain will continue to
show a slow decrease in areal coverage and intensity as the vort
moves off to the east. Focus for additional showers and
thunderstorms this evening will then shift closer to a front over
southern Missouri into southern Illinois. RAP and Local WRF shows
low level forcing persisting along and north of this front most of
the night, so will keep chances of showers and thunderstorms mainly
in areas along and south of I-44 in Missouri and I-64 in
Illinois.
Britt
.LONG TERM: (Saturday through Next Friday)
Issued at 317 PM CDT Fri Aug 9 2013
Primary concern for Saturday through early next week continues to be
timing and intensity of precipitation as quasi-zonal/northwest flow
pattern continues to control our weather. Am continuing the
persistence forecast with high chance/likely pops across the eastern
Ozarks and extreme southwest Illinois, fading to low chance/slight
chance up along the I-70 corridor for Saturday. This morning`s
850mb analysis showed a strong dewpoint gradient along the I-70 with
northerly flow across northern Missouri and moist west-southwest
flow to the south of the gradient. This gradient along with the
northerly flow feeding it is probably at least partially responsible
for the lack of northward progress for today`s precipitation. All
short range guidance keeps the 850mb dewpoint gradient in basically
the same place, hence the persistence forecast. The gradient washes
out on Sunday allowing deeper moisture to filter back into the
region. However, there appears to be a general lack of dynamic
forcing on Sunday with just some weak isentropic lift on 10kt low
level southwest flow. With nothing obvious to focus convection,
will spread chance pops further north, but am not particularly
excited about going with pops higher than chance anywhere at this
time. On Monday, a strong shortwave is forecast to drop down into
the Great Lakes region which should amplify the eastern trof and
push a cold front into the mid Mississippi Valley with a
corresponding increase in pops across the area.
Medium range guidance shows a sprawling high pressure system
building down across the Upper Midwest into the Great Lakes region
late Tuesday into Wednesday. This airmass will be cooler and much
drier than is normal for mid August. 850mb temps on the GFS are
progged to be around 10-12C...which would mix down to the low to mid
70s. The ECMWF is somewhat warmer at 12-14C. Given the
discrepancy...have opted to to stick with ensemble guidance with
highs in the upper 70s to low 80s and lows in the upper 50s to low
to 60s.
Carney
&&
.AVIATION: (For the 00z TAFs through 00z Saturday Evening)
Issued at 541 PM CDT Fri Aug 9 2013
Scattered light showers and sprinkles will continue during the
early evening hours. There was scattered showers along a
secondary weak cold front extending from nrn IL sw through nwrn MO
and dropping slowly sewd. Most of this activity on the front will
likely dissipate later this evening with loss of daytime heating.
Focus for significant convection later tonight and SAT should
continue to be s of the taf sites. There should be mainly VFR low-
mid level cloudiness tonight...although there will be patchy MVFR
stratus clouds tonight along with patchy fog late tonight/early
SAT morning...especially at SUS...with a light nly sfc wind. Much
of the low-mid level cloud cover will shift s of the taf sites by
late sat morning into the afternoon with a n-nely sfc wind only
increasing to around 7 kts.
Specifics for KSTL: Should have intermittent sprinkles early this
evening. VFR low-mid level clouds will continue tgt into SAT
morning, then scatter out by late SAT morning or afternoon. Nly
sfc wind will become light later this evening...then increase to
around 7 kts SAT afternoon.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
720 PM CDT Fri Aug 9 2013
.UPDATE:
Issued at 720 PM CDT Fri Aug 9 2013
A weak cold front exists from NE MO to just S of the Chicago area.
This front has generated scattered SHRA/TSRA along it but is
showing signs of fading as it moves SE into an area that has been
under clouds all day and is slightly more stable, plus the sun is
going down, so do not expect this to hang on for much longer and
probably will not impact the forecast.
Further south into the I-70 corridor, the atmospheric column is
much more moist, with an upper level disturbance near central MO
creating an area of SHRA just ahead of it. Further downstream, we
are seeing sprinkles from a mid deck of clouds. We should see more
of the same heading into the night, with scattered sprinkles
downstream of the upper level disturbance, but as this disturbance
moves east down I-70, we will see enhanced chances for measuring
showers. This disturbance should exit SW IL shortly after
midnight.
Just south of the forecast area, an old stationary frontal
boundary exists and has been the main focus for waves of rain for
the past several nights on the cool side. This night will probably
not be much different, with another wave of SHRA/TSRA expected to
move into SE MO Saturday morning and make another run towards I-70
during the day before receding late in the day.
TES
&&
.SHORT TERM: (Through Late Tonight)
Issued at 317 PM CDT Fri Aug 9 2013
Area of rain extending from central Missouri into southwest Illinois
has persisted on the north side of a side of MCV that is currently
tracking through southeast Missouri. This rain will continue to
show a slow decrease in areal coverage and intensity as the vort
moves off to the east. Focus for additional showers and
thunderstorms this evening will then shift closer to a front over
southern Missouri into southern Illinois. RAP and Local WRF shows
low level forcing persisting along and north of this front most of
the night, so will keep chances of showers and thunderstorms mainly
in areas along and south of I-44 in Missouri and I-64 in
Illinois.
Britt
.LONG TERM: (Saturday through Next Friday)
Issued at 317 PM CDT Fri Aug 9 2013
Primary concern for Saturday through early next week continues to be
timing and intensity of precipitation as quasi-zonal/northwest flow
pattern continues to control our weather. Am continuing the
persistence forecast with high chance/likely pops across the eastern
Ozarks and extreme southwest Illinois, fading to low chance/slight
chance up along the I-70 corridor for Saturday. This morning`s
850mb analysis showed a strong dewpoint gradient along the I-70 with
northerly flow across northern Missouri and moist west-southwest
flow to the south of the gradient. This gradient along with the
northerly flow feeding it is probably at least partially responsible
for the lack of northward progress for today`s precipitation. All
short range guidance keeps the 850mb dewpoint gradient in basically
the same place, hence the persistence forecast. The gradient washes
out on Sunday allowing deeper moisture to filter back into the
region. However, there appears to be a general lack of dynamic
forcing on Sunday with just some weak isentropic lift on 10kt low
level southwest flow. With nothing obvious to focus convection,
will spread chance pops further north, but am not particularly
excited about going with pops higher than chance anywhere at this
time. On Monday, a strong shortwave is forecast to drop down into
the Great Lakes region which should amplify the eastern trof and
push a cold front into the mid Mississippi Valley with a
corresponding increase in pops across the area.
Medium range guidance shows a sprawling high pressure system
building down across the Upper Midwest into the Great Lakes region
late Tuesday into Wednesday. This airmass will be cooler and much
drier than is normal for mid August. 850mb temps on the GFS are
progged to be around 10-12C...which would mix down to the low to mid
70s. The ECMWF is somewhat warmer at 12-14C. Given the
discrepancy...have opted to to stick with ensemble guidance with
highs in the upper 70s to low 80s and lows in the upper 50s to low
to 60s.
Carney
&&
.AVIATION: (For the 00z TAFs through 00z Saturday Evening)
Issued at 541 PM CDT Fri Aug 9 2013
Scattered light showers and sprinkles will continue during the
early evening hours. There was scattered showers along a
secondary weak cold front extending from nrn IL sw through nwrn MO
and dropping slowly sewd. Most of this activity on the front will
likely dissipate later this evening with loss of daytime heating.
Focus for significant convection later tonight and SAT should
continue to be s of the taf sites. There should be mainly VFR low-
mid level cloudiness tonight...although there will be patchy MVFR
stratus clouds tonight along with patchy fog late tonight/early
SAT morning...especially at SUS...with a light nly sfc wind. Much
of the low-mid level cloud cover will shift s of the taf sites by
late sat morning into the afternoon with a n-nely sfc wind only
increasing to around 7 kts.
Specifics for KSTL: Should have intermittent sprinkles early this
evening. VFR low-mid level clouds will continue tgt into SAT
morning, then scatter out by late SAT morning or afternoon. Nly
sfc wind will become light later this evening...then increase to
around 7 kts SAT afternoon.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
608 PM CDT Fri Aug 9 2013
.SHORT TERM: (Through Late Tonight)
Issued at 317 PM CDT Fri Aug 9 2013
Area of rain extending from central Missouri into southwest Illinois
has persisted on the north side of a side of MCV that is currently
tracking through southeast Missouri. This rain will continue to
show a slow decrease in areal coverage and intensity as the vort
moves off to the east. Focus for additional showers and
thunderstorms this evening will then shift closer to a front over
southern Missouri into southern Illinois. RAP and Local WRF shows
low level forcing persisting along and north of this front most of
the night, so will keep chances of showers and thunderstorms mainly
in areas along and south of I-44 in Missouri and I-64 in
Illinois.
Britt
.LONG TERM: (Saturday through Next Friday)
Issued at 317 PM CDT Fri Aug 9 2013
Primary concern for Saturday through early next week continues to be
timing and intensity of precipitation as quasi-zonal/northwest flow
pattern continues to control our weather. Am continuing the
persistence forecast with high chance/likely pops across the eastern
Ozarks and extreme southwest Illinois, fading to low chance/slight
chance up along the I-70 corridor for Saturday. This morning`s
850mb analysis showed a strong dewpoint gradient along the I-70 with
northerly flow across northern Missouri and moist west-southwest
flow to the south of the gradient. This gradient along with the
northerly flow feeding it is probably at least partially responsible
for the lack of northward progress for today`s precipitation. All
short range guidance keeps the 850mb dewpoint gradient in basically
the same place, hence the persistence forecast. The gradient washes
out on Sunday allowing deeper moisture to filter back into the
region. However, there appears to be a general lack of dynamic
forcing on Sunday with just some weak isentropic lift on 10kt low
level southwest flow. With nothing obvious to focus convection,
will spread chance pops further north, but am not particularly
excited about going with pops higher than chance anywhere at this
time. On Monday, a strong shortwave is forecast to drop down into
the Great Lakes region which should amplify the eastern trof and
push a cold front into the mid Mississippi Valley with a
corresponding increase in pops across the area.
Medium range guidance shows a sprawling high pressure system
building down across the Upper Midwest into the Great Lakes region
late Tuesday into Wednesday. This airmass will be cooler and much
drier than is normal for mid August. 850mb temps on the GFS are
progged to be around 10-12C...which would mix down to the low to mid
70s. The ECMWF is somewhat warmer at 12-14C. Given the
discrepancy...have opted to to stick with ensemble guidance with
highs in the upper 70s to low 80s and lows in the upper 50s to low
to 60s.
Carney
&&
.AVIATION: (For the 00z TAFs through 00z Saturday Evening)
Issued at 541 PM CDT Fri Aug 9 2013
Scattered light showers and sprinkles will continue during the
early evening hours. There was scattered showers along a
secondary weak cold front extending from nrn IL sw through nwrn MO
and dropping slowly sewd. Most of this activity on the front will
likely dissipate later this evening with loss of daytime heating.
Focus for significant convection later tonight and SAT should
continue to be s of the taf sites. There should be mainly VFR low-
mid level cloudiness tonight...although there will be patchy MVFR
stratus clouds tonight along with patchy fog late tonight/early
SAT morning...especially at SUS...with a light nly sfc wind. Much
of the low-mid level cloud cover will shift s of the taf sites by
late sat morning into the afternoon with a n-nely sfc wind only
increasing to around 7 kts.
Specifics for KSTL: Should have intermittent sprinkles early this
evening. VFR low-mid level clouds will continue tgt into SAT morning
...then scatter out by late SAT morning or afternoon. Nly sfc
wind will become light later this evening...then increase to around
7 kts SAT afternoon.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
111 PM CDT Thu Aug 8 2013
.UPDATE:
Issued at 1004 AM CDT Thu Aug 8 2013
Have updated forecast to reflect that area of showers and thunderstorms
over the Ozarks continues to moves east and slightly north. In addition,
scattered thunderstorms have developed recently along the across
Gasconade and Franklin counties. Latest runs of the HRRR and RAP
are showing that a low level moisture convergence maximum will
move east into southern Illinois later this morning. Now believe
that north edge of the rain will move north to about the Missouri
River before diminishing with greatest chances shifting eastward
from the Ozarks into southern Illinois. Will keep with the idea
that areal coverage of the rain will diminish early-mid afternoon.
Then the atmosphere will become increasing unstable by late
afternoon, particularly over southern Missouri at the same time
that low level moisture convergences increases from southern
Missouri into central Missouri between 21-00Z. HRRR reflectivity
shows that discrete storms may initially develop late this
afternoon into early this evening. A few severe thunderstorms will
be possible depending on the amount of instability that is able to
work into the area. Storms will also be possible of producing
heavy rainfall rates.
Britt
&&
.SHORT TERM: (Through Sunday)
Issued at 404 AM CDT Thu Aug 8 2013
Cold front is now over southern portions of forecast area early
this morning. Storms that had fired along it have long since
dissipated. Otherwise...storms have fired on nose of low level jet
once again, but further south over far southwestern Missouri.
Also, an MCS has developed over north central Oklahoma and it`s
associated MCV will continue to track to the east along frontal
boundary today. So will see scattered storms fire and move along
front, making some progress to the north, but remain along and
south of I-70. Because of the light surface winds and plenty of
low level moisture, some patchy dense fog has developed over far
southern and eastern portions of forecast area this morning, but
should dissipate as high and mid clouds move in later this
morning. As for high temperatures, low to mid 80s a good bet.
By tonight, models continue to develop another MCS over eastern
Kansas and slide it east, but have differing opinions on placement
of system, with NAM the furthest north. Will go with a blend of the
models and keep likely pops going for tonight for a good portion of
the forecast area, but back off main area of activity til after 06z
and continue through day on Friday before tapering off Friday night.
Will see decent qpf amounts, but placement of heaviest rains still
hard to pin down, so will not issue a Flash Flood Watch at this
time. One may be needed for late tonight through Friday,
especially for central and southern portions of forecast area. Lows
tonight will be in the mid 60s to around 70 with highs on Friday
in the upper 70s to mid 80s.
Weak surface ridge is still expected to build in for the weekend and
into early next week, so precipitation chances to shift off to the
south, though kept chance pops for southeast Missouri and far
southwestern Illinois through Sunday. Highs to remain below normal
in the low to mid 80s through the weekend.
Byrd
.LONG TERM: (Sunday Night through Wednesday)
Issued at 404 AM CDT Thu Aug 8 2013
Surface ridge to move off to the east ahead of next weather system
by Monday, so have chances of showers and thunderstorms across the
area on Monday as system moves through, tapering off Monday night.
Then dry conditions return to the region for the rest of the
forecast period with below normal temperatures.
Byrd
&&
.AVIATION: (For the 18z TAFs through 18z Friday Afternoon)
Issued at 111 PM CDT Thu Aug 8 2013
Area of showers and thunderstorms is quickly diminishing as it
moves east. Still expect 1-2 more hours of light rain at the St.
Louis metro area TAF sites before it ends. There will also be some
lingering MVFR (isolated IFR) ceilings and visibilities before
turning VFR later this afternoon. Additional thunderstorm
development will be possible later this afternoon and this
evening...particularly over southern Missouri. Better chance for
rain with MVFR ceilings and visibilities will be between 06-14Z
Saturday when another complex of thunderstorms is expected to move
across southern Missouri.
Specifics for KSTL: Expect dry and VFR conditions to return to
airport in the next hour. Airport may see additional thunderstorms
late tonight and early Saturday on the northern fringe of another
complex of storms. This rain may bring MVFR ceilings and
visibilities with it.
Britt
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1226 PM CDT Thu Aug 8 2013
.SHORT TERM...(Today through Friday)
Issued at 322 AM CDT THU AUG 8 2013
Another night of conceptual forecasting as none of the 00Z solutions
have initialized the anticipated MCS riding along the KS/OK border,
and continue to poorly handle the subtle but key features emanating
out of the western trough each afternoon. The HRRR continues to
perform exceptionally well (albeit slow on timing), but its short-
term guidance only goes so far. In any case, 07Z surface analysis
depicts a strongly convergent frontal zone across nrn OK/AR with the
greatest lift once again focused about 50 miles north of this
boundary. A secondary elevated boundary, roughly juxtaposed with the
southern extent of dry surface air, extends NE from Wichita to
Clinton to Jefferson City. Developing MCV along over SW KS will
likely begin to make the turn ENE along this northern boundary.
With that said, dry northeasterly flow should keep most of the CWA
quiet through daybreak. Much like the past several nights, a sub-
synoptic occlusion should occur as the eastward advancing MCS
overtakes the W-E stationary front. This would place the southwestern
zones under the best chances for thunder by 12Z, with a rapid
transition to a stratiform rain/embedded thunder event as an
enlarging precipitation shield pushes into the dry air over east
central KS/west central MO. A well-defined MCV should lift slowly
across the southern CWA during the day, with QPF diminishing.
The MCV passage will mark the return of deeper warm/air moisture
advection that will place us back in a preferred zone for deep moist
convection tonight and Friday. As for highs today, generally went
around 80 across the board. Despite better chances for sunshine over
the NE CWA (at least early), CAA should yield similar readings as
points further south. Convective debris/showers should limit
insolation over the srn CWA through the morning, but expect some PM
sun to boost them back up.
For tonight, the large scale mid-level trough will begin to
finally eject out of the central Rockies, establishing a surface low
across OK. Deepening southwesterly flow aloft will lift the surface
warm front back to near I-44. This will place the southern CWA in a
precarious region of strong deep layer ascent/convergence amidst
increasing moisture advection. Based only on persistence from the
past 4-5 days, greatest QPF should fall in the 06-15Z time frame
Friday. Given the frontogenetic forcing, upper support and boundary-
relative shear profiles, have significantly bumped POPs and QPF from
06Z-18Z Friday. A flash flood watch will likely be required south of
the MO river given antecedent rainfall and prospects for very heavy
rainfall tonight/Friday morning.
Highs Friday honestly a hedge toward some afternoon clearing, but
could conceivably end up in the low-mid 70s if this doesn`t occur.
Friday Night remains the biggest question mark given the large model
spread in timing of the upper trough passage. Areas along/ahead of
this mid level wind shift certainly remain under the gun for
additional precipitation and have retained moderate POPs across all
but far NW MO for that reason.
.LONG TERM...(Saturday through Wednesday)
Issued at 322 AM CDT THU AUG 8 2013
The upcoming weekend should remain dry as the region will fall under
the influence of high pressure moving southeast through the Great
Lakes. With little change in the synoptic pattern and a continuance
of progressive zonal to northwesterly flow heading into into next
week, it appears there will only be a short break to the rainfall in
the region. By Monday, upper troughing will temporarily deepen over
Manitoba and Ontario, pushing a weak shortwave into the Central
Plains. Increasing warm advection ahead of this wave will induce
showers and thunderstorms over a large area of the central CONUS
Monday into Monday night. Have increased PoPs from late Sunday
night into Tuesday morning.
Latest guidance suggests a cold front will sweep southward through
the region by Tuesday morning, with high pressure once again moving
into the western Great Lakes providing dry conditions to the local
area.
As far as temperatures are concerned, warm advection and
southwesterly surface flow on Sunday will push temperatures back
towards seasonal normals. However, past the frontal passage on
Tuesday, temperatures will likely remain below normal into the
middle of next week.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday Afternoon)
Issued at 1226 PM CDT THU AUG 8 2013
Over the next 2-3 hours, scattered light rain showers will continue
to lift east northeast across central and northeast KS, but will
gradually erode just east of the Missouri border. Ceilings with this
area of precipitation should stay around 10 kft; thus, much of the
region should remain VFR through at least 09z. Showers and storms are
still expected to develop across south central KS after midnight and
lift into the region between 09z-12z Friday. Most precipitation
should remain focused along and south of I-70, and should begin to
weaken and push off to the east around 18z Friday. Winds will remain
around or less than 10 kts through the period, varying in direction
from northeast to east.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...FLASH FLOOD WATCH from Midnight CDT tonight through Friday
morning FOR KSZ057-060-105.
MO...FLASH FLOOD WATCH from Midnight CDT tonight through Friday
morning FOR MOZ037>040-043>046-053-054.
&&
$$
SHORT TERM...Bookbinder
LONG TERM...Dux
AVIATION...Laflin
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1010 AM CDT Thu Aug 8 2013
.UPDATE:
Issued at 1004 AM CDT Thu Aug 8 2013
Have updated forecast to reflect that area of showers and thunderstorms
over the Ozarks continues to moves east and slightly north. In addition,
scattered thunderstorms have developed recently along the across
Gasconade and Franklin counties. Latest runs of the HRRR and RAP
are showing that a low level moisture convergence maximum will
move east into southern Illinois later this morning. Now believe
that north edge of the rain will move north to about the Missouri
River before diminishing with greatest chances shifting eastward
from the Ozarks into southern Illinois. Will keep with the idea
that areal coverage of the rain will diminish early-mid afternoon.
Then the atmosphere will become increasing unstable by late
afternoon, particularly over southern Missouri at the same time
that low level moisture convergences increases from southern
Missouri into central Missouri between 21-00Z. HRRR reflectivity
shows that discrete storms may initially develop late this
afternoon into early this evening. A few severe thunderstorms will
be possible depending on the amount of instability that is able to
work into the area. Storms will also be possible of producing
heavy rainfall rates.
Britt
&&
.SHORT TERM: (Through Sunday)
Issued at 404 AM CDT Thu Aug 8 2013
Cold front is now over southern portions of forecast area early
this morning. Storms that had fired along it have long since
dissipated. Otherwise...storms have fired on nose of low level jet
once again, but further south over far southwestern Missouri.
Also, an MCS has developed over north central Oklahoma and it`s
associated MCV will continue to track to the east along frontal
boundary today. So will see scattered storms fire and move along
front, making some progress to the north, but remain along and
south of I-70. Because of the light surface winds and plenty of
low level moisture, some patchy dense fog has developed over far
southern and eastern portions of forecast area this morning, but
should dissipate as high and mid clouds move in later this
morning. As for high temperatures, low to mid 80s a good bet.
By tonight, models continue to develop another MCS over eastern
Kansas and slide it east, but have differing opinions on placement
of system, with NAM the furthest north. Will go with a blend of the
models and keep likely pops going for tonight for a good portion of
the forecast area, but back off main area of activity til after 06z
and continue through day on Friday before tapering off Friday night.
Will see decent qpf amounts, but placement of heaviest rains still
hard to pin down, so will not issue a Flash Flood Watch at this
time. One may be needed for late tonight through Friday,
especially for central and southern portions of forecast area. Lows
tonight will be in the mid 60s to around 70 with highs on Friday
in the upper 70s to mid 80s.
Weak surface ridge is still expected to build in for the weekend and
into early next week, so precipitation chances to shift off to the
south, though kept chance pops for southeast Missouri and far
southwestern Illinois through Sunday. Highs to remain below normal
in the low to mid 80s through the weekend.
Byrd
.LONG TERM: (Sunday Night through Wednesday)
Issued at 404 AM CDT Thu Aug 8 2013
Surface ridge to move off to the east ahead of next weather system
by Monday, so have chances of showers and thunderstorms across the
area on Monday as system moves through, tapering off Monday night.
Then dry conditions return to the region for the rest of the
forecast period with below normal temperatures.
Byrd
&&
.AVIATION: (For the 12z TAFs through 12z Friday Morning)
Issued at 642 AM CDT Thu Aug 8 2013
Areas of ifr cigs are floating around far eastern missouri early
this morning while they become more continuous into illinois. this
low cloud may impact the st louis area taf sites through 14z then
expecting generally vfr conditions with scattered cu and high
clouds to prevail through the evening. the exception to this is
central missouri and kcou where I`m still expecting vfr conditions
but some showers could move into around midday and last for
several hours. for tonight mvfr cigs should redevelop across the
area late tonight with showers and maybe a few thunderstorms
spreading from west to east.
Specifics for KSTL:
Areas of ifr cigs are floating around far eastern missouri early
this morning and they could impact the terminal through 14z.
thereafter expecting generally vfr conditions with scattered cu
and high clouds to prevail through the evening. mvfr cigs should
redevelop across the area late tonight with showers and maybe a
few thunderstorms spreading in from the west near daybreak friday.
Glass
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
647 AM CDT Thu Aug 8 2013
.SHORT TERM...(Today through Friday)
Issued at 322 AM CDT THU AUG 8 2013
Another night of conceptual forecasting as none of the 00Z solutions
have initialized the anticipated MCS riding along the KS/OK border,
and continue to poorly handle the subtle but key features emanating
out of the western trough each afternoon. The HRRR continues to
perform exceptionally well (albeit slow on timing), but its short-
term guidance only goes so far. In any case, 07Z surface analysis
depicts a strongly convergent frontal zone across nrn OK/AR with the
greatest lift once again focused about 50 miles north of this
boundary. A secondary elevated boundary, roughly juxtaposed with the
southern extent of dry surface air, extends NE from Wichita to
Clinton to Jefferson City. Developing MCV along over SW KS will
likely begin to make the turn ENE along this northern boundary.
With that said, dry northeasterly flow should keep most of the CWA
quiet through daybreak. Much like the past several nights, a sub-
synoptic occlusion should occur as the eastward advancing MCS
overtakes the W-E stationary front. This would place the southwestern
zones under the best chances for thunder by 12Z, with a rapid
transition to a stratiform rain/embedded thunder event as an
enlarging precipitation shield pushes into the dry air over east
central KS/west central MO. A well-defined MCV should lift slowly
across the southern CWA during the day, with QPF diminishing.
The MCV passage will mark the return of deeper warm/air moisture
advection that will place us back in a preferred zone for deep moist
convection tonight and Friday. As for highs today, generally went
around 80 across the board. Despite better chances for sunshine over
the NE CWA (at least early), CAA should yield similar readings as
points further south. Convective debris/showers should limit
insolation over the srn CWA through the morning, but expect some PM
sun to boost them back up.
For tonight, the large scale mid-level trough will begin to
finally eject out of the central Rockies, establishing a surface low
across OK. Deepening southwesterly flow aloft will lift the surface
warm front back to near I-44. This will place the southern CWA in a
precarious region of strong deep layer ascent/convergence amidst
increasing moisture advection. Based only on persistence from the
past 4-5 days, greatest QPF should fall in the 06-15Z time frame
Friday. Given the frontogenetic forcing, upper support and boundary-
relative shear profiles, have significantly bumped POPs and QPF from
06Z-18Z Friday. A flash flood watch will likely be required south of
the MO river given antecedent rainfall and prospects for very heavy
rainfall tonight/Friday morning.
Highs Friday honestly a hedge toward some afternoon clearing, but
could conceivably end up in the low-mid 70s if this doesn`t occur.
Friday Night remains the biggest question mark given the large model
spread in timing of the upper trough passage. Areas along/ahead of
this mid level wind shift certainly remain under the gun for
additional precipitation and have retained moderate POPs across all
but far NW MO for that reason.
.LONG TERM...(Saturday through Wednesday)
Issued at 322 AM CDT THU AUG 8 2013
The upcoming weekend should remain dry as the region will fall under
the influence of high pressure moving southeast through the Great
Lakes. With little change in the synoptic pattern and a continuance
of progressive zonal to northwesterly flow heading into into next
week, it appears there will only be a short break to the rainfall in
the region. By Monday, upper troughing will temporarily deepen over
Manitoba and Ontario, pushing a weak shortwave into the Central
Plains. Increasing warm advection ahead of this wave will induce
showers and thunderstorms over a large area of the central CONUS
Monday into Monday night. Have increased PoPs from late Sunday
night into Tuesday morning.
Latest guidance suggests a cold front will sweep southward through
the region by Tuesday morning, with high pressure once again moving
into the western Great Lakes providing dry conditions to the local
area.
As far as temperatures are concerned, warm advection and
southwesterly surface flow on Sunday will push temperatures back
towards seasonal normals. However, past the frontal passage on
Tuesday, temperatures will likely remain below normal into the
middle of next week.
&&
.AVIATION...(For the 12Z TAFS through 12Z Friday Morning)
Issued at 644 AM CDT THU AUG 8 2013
Mesoscale convective complex continues to move ENE across southern KS
early this morning. As cloud tops have begun to warm, sharp linear
convection has now broadened into an expanding area of stratiform
rain with embedded thunder. This precipitation will be moving into an
area of drier air, so uncertainty remains as to how far northeast
lightning will persist as the system approaches. Since conditions
will otherwise be VFR, this is really the only aspect of this MCC
that is impactful to the terminals this morning. For now went with a
tempo group for thunder across the KC terminals from 14-16Z based on
linear extrapolation.
Otherwise, as the system decays, winds should remain east-northeast
to northeast at 6-8 knots, with speeds slowly increasing tonight
ahead of the next disturbance. Conditions appear favorable,
especially south of Kansas City, for an organized thunderstorm
complex once again after midnight. Outlook period of the TAF reflects
a somewhat higher confidence for rain/embedded thunder and perhaps
some lower ceilings after midnight.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...FLASH FLOOD WATCH from late tonight through Friday morning FOR
KSZ057-060-105.
MO...FLASH FLOOD WATCH from late tonight through Friday morning FOR
MOZ037>040-043>046-053-054.
&&
$$
SHORT TERM...Bookbinder
LONG TERM...Dux
AVIATION...Bookbinder
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
330 AM CDT Thu Aug 8 2013
.SHORT TERM...(Today through Friday)
Issued at 322 AM CDT THU AUG 8 2013
Another night of conceptual forecasting as none of the 00Z solutions
have initialized the anticipated MCS riding along the KS/OK border,
and continue to poorly handle the subtle but key features emanating
out of the western trough each afternoon. The HRRR continues to
perform exceptionally well (albiet slow on timing), but its short-
term guidance only goes so far. In any case, 07Z surface analysis
depicts a strongly convergent frontal zone across nrn OK/AR with the
greatest lift once again focused about 50 miles north of this
boundary. A secondary elevated boundary, roughly juxtaposed with the
southern extent of dry surface air, extends NE from Wichita to
Clinton to Jefferson City. Developing MCV along over SW KS will
likely begin to make the turn ENE along this northern boundary. Its
also possible that additional showers/storms develop along this
elevated boundary over the next several hours, remaining /just/ south
of the CWA border.
With that said, dry northeasterly flow should keep most of the CWA
quiet through daybreak. Much like the past several nights, a sub-
synoptic occlusion should occur as the eastward advancing MCS
overtakes the W-E stationary front. This would place the southwestern
zones under the best chances for thunder by 12Z, with more
stratiform rain/embedded rumbles further north. The MCV should lift
slowly NE across the CWA during the day, with QPF diminishing.
However, the MCV passage will mark the return of deeper warm/air
moisture advection that will place us back in a preferred zone for
deep moist convection tonight and Friday. As for highs today,
generally went around 80 across the board. Despite better chances for
sunshine over the NE CWA (at least early), CAA should yield similar
readings as points further south. Convective debris/showers should
limit insolation over the srn CWA through the morning, but expect
some PM sun to boost them back up.
For tonight, the large scale mid-level trough will begin to
finally eject out of the central Rockies, establishing a surface low
across OK. Deepening southwesterly flow aloft will lift the surface
warm front back to near I-44. This will place the southern CWA in a
precarious region of strong deep layer ascent/convergence amidst
increasing moisture advection. Based only on persistence from the
past 4-5 days, greatest QPF should fall in the 06-15Z time frame
Friday. Given the frontogenetic forcing, upper support and boundary-
relative shear profiles, have significantly bumped POPs and QPF from
06Z-18Z Friday. A flash flood watch will likely be required south of
the MO river given antecedent rainfall and prospects for very heavy
rainfall tonight/Friday morning.
Highs Friday honestly a hedge toward some afternoon clearing, but
could conceivably end up in the low-mid 70s if this doesn`t occur.
Friday Night remains the biggest question mark given the large model
spread in timing of the upper trough passage. Areas along/ahead of
this mid level wind shift certainly remain under the gun for
additional precipitation and have retained moderate POPs across all
but far NW MO for that reason.
.LONG TERM...(Saturday through Wednesday)
Issued at 322 AM CDT THU AUG 8 2013
The upcoming weekend should remain dry as the region will fall under
the influence of high pressure moving southeast through the Great
Lakes. With little change in the synoptic pattern and a continuance
of progressive zonal to northwesterly flow heading into into next
week, it appears there will only be a short break to the rainfall in
the region. By Monday, upper troughing will temporarily deepen over
Manitoba and Ontario, pushing a weak shortwave into the Central
Plains. Increasing warm advection ahead of this wave will induce
showers and thunderstorms over a large area of the central CONUS
Monday into Monday night. Have increased PoPs from late Sunday
night into Tuesday morning.
Latest guidance suggests a cold front will sweep southward through
the region by Tuesday morning, with high pressure once again moving
into the western Great Lakes providing dry conditions to the local
area.
As far as temperatures are concerned, warm advection and
southwesterly surface flow on Sunday will push temperatures back
towards seasonal normals. However, past the frontal passage on
Tuesday, temperatures will likely remain below normal into the
middle of next week.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday Night)
Issued at 1153 PM CDT WED AUG 7 2013
VFR conditions are expected through the entire forecast. There may be
a brief period around sunrise of minor fog or haze reducing
visibilities to around 4 miles or so. Have kept this out of the
forecast for now as winds around 5 knots from the north to northeast
should keep the lowest levels mixed enough to prevent much fog
formation. Otherwise, only mid to high level clouds are expected with
winds becoming more easterly tomorrow but still remaining light. any
chances for storms should remain to the south for the rest of the
overnight. A dying area of showers or storms is possible by late
morning but the dry air in the lowest levels may kill things off
before getting to the terminals.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
SHORT TERM...Bookbinder
LONG TERM...Dux
AVIATION...CDB
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
933 PM MDT Fri Aug 9 2013
.UPDATE...
Scattered afternoon thunderstorms dissipated with sunset. However,
an upper level shortwave feature lifting northward through western
Montana is associated with a line of thunderstorms from Missoula to
Helena and Bozeman. Evening HRRR guidance splits a portion of the
shortwave to the east and brings precipitation through N. central
MT through 12Z Saturday morning. Satellite and radar trends this
split as thunderstorms in NW Montana are drifting NW while those
in the Helena area are drifting NE. RUC and NAM guidance do not
support this nocturnal activity as thunderstorms encounter the
relatively cooler and more stable air mass in place over N.
central MT. Raised POPs along the Rocky Mountain front for tonight
to reflect these trends. Nutter
&&
.AVIATION...
UPDATED 2344Z.
A weak upper level disturbance and an unstable airmass will keep
isolated to scattered thunderstorms across central Montana. Most
thunderstorm activity is expected to consist of heavy rain and small
hail. In addition, gusty surface winds should be expected near
thunderstorms but otherwise, winds will remain light. The airmass
becomes unstable again Saturday afternoon and scattered
thunderstorms are again expected. MVFR conditions are possible near
showers and thunderstorms. Elsewhere, VFR conditions will prevail
through the next 24 hours.
&&
.PREV DISCUSSION...
/ISSUED 550 PM MDT Fri Aug 9 2013/
Tonight through Sunday...Monsoonal moisture continues to be drawn
up and across southern Montana this afternoon resulting in the
development of scattered thunderstorms. Moisture is present as
well as decent CAPE values but the shear environment is marginal
at best. As a result, the storms are fairly slow moving and
generally low-topped. With precipitable water values continuing
around an inch or so, heavy rains are possible with these
thunderstorms. Convective activity should gradually end by
midnight with clearing skies. Saturday looks to be a similar day
to today as monsoonal moisture will continue to move north.
Thunderstorms will develop again Saturday afternoon and will be a
bit more widespread in areal coverage. Isolated to scattered
thunderstorms will continue Sunday afternoon and evening as
conditions will change little through the weekend. Temperatures
will warm over the weekend with readings slightly above seasonal
averages. Emanuel
Sunday night through Friday...Early in the week an upper ridge is
forecast to be over the Rockies with southwest to west flow aloft
over the forecast area. Expect a few weather disturbances to be
embedded in the flow aloft but the models are not in good agreement
with their details so will employ a broadbrush approach to the
forecast. There is some evidence from the models that southwest
Montana could have a drier airmass in comparison to locations
farther north so during the afternoon and evening will generally go
with isolated thunderstorms over southwest Montana and scattered
thunderstorms over northwest Montana. Also will play the diurnal
card and have lower chances of precipitation during the late night
and morning relative to during the afternoon and evening. Thursday
the latest GEM (Canadian) and ECMWF (European) model runs redevelop
the upper ridge west of the forecast area and then move it over the
forecast area by early Friday. The GFS (U.S.) model run does not
forecast this redevelopment and continues a southwest flow aloft.
However other forecast guidance from the GFS does show some support
for the ECMWF solution for Friday. Will go with slightly lower
chances of precipitation later in the week relative to early in the
week due to the possibility of an upper ridge over the forecast area
later in the week. Expect little day-to-day change in high
temperatures with highs in the 80s.
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 54 86 55 88 / 20 30 20 20
CTB 51 82 52 83 / 20 20 20 50
HLN 56 88 57 89 / 30 30 20 20
BZN 49 88 49 88 / 30 30 20 20
WEY 37 79 37 78 / 20 20 10 10
DLN 48 85 49 85 / 20 30 20 20
HVR 53 83 55 85 / 10 20 20 20
LWT 52 81 54 83 / 30 30 30 20
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING until 10 PM MDT this evening Beaverhead...
Jefferson...Madison.
&&
$$
weather.gov/greatfalls
AREA FORECAST DISCUSSION...UPDATED
NWS GLASGOW MT
822 PM MDT FRI AUG 9 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SUNDAY...
SENT AN UPDATE TONIGHT TO MORE ACCURATELY REFLECT THE RECENT RADAR
TRENDS COMBINED WITH THE LATEST CONVECTIVE OUTLOOKS FROM SPC. CUT
BACK POPS TONIGHT TO SPRINKLES...THEN SLIGHT CHANCE STRIP OF
SHOWERS OVERNIGHT...FALLING MORE IN LINE WITH RECENTLY UPDATED
SHORT TERM AND HIGH RESOLUTION MODEL CONSENSUS. BMICKELSON
PREVIOUS SHORT TERM DISCUSSION...MAIN CONCERN THIS EVENING WILL
BE CONVECTIVE POTENTIAL FOR THE SOUTHERN ZONES. MAINTAINED
ISOLATED MENTION...HOWEVER...BEST INSTABILITY LOOKS TO REMAIN
SOUTH OF THE FORECAST REGION. THERE IS EXCELLENT AGREEMENT ON THIS
IDEA FROM THE 12Z/09 MODEL GUIDANCE. THE GFS IS FURTHER SOUTH BUT
THE NAM/ECMWF BRINGS QPF CLOSE ENOUGH TO THE CWA THAT LEAVING IN
ISOLATED SHOWERS/THUNDERSTORMS IS ACCEPTABLE. THIS HAS FURTHER
SUPPORT FROM RECENT HRRR MODEL RUNS AS WELL. OTHERWISE IT LOOKS
LIKE IT WILL BE A QUIET EVENING ACROSS NORTHEAST MONTANA WITH
NORTHWEST FLOW ALOFT DOMINATING AS A RESULT OF A RIDGE ACROSS THE
WESTERN PORTIONS OF THE STATE.
SATURDAY INTO SATURDAY NIGHT...A MOIST UNSTABLE AIR MASS TO THE SOUTH
OF THE CWA WILL GRADUALLY LIFT NORTHWARD. CURRENT ECMWF BRINGS
OVER 1000 J/KG OF CAPE INTO PETROLEUM COUNTY AND SOUTHERN
GARFIELD. PROXIMITY TO THE RIDGE MAY KEEP ENOUGH LARGE SCALE
SUBSIDENCE IN PLACE THAT WIDESPREAD CONVECTION WOULD SEEM
UNLIKELY. GIVEN ABUNDANT CAPE HOWEVER IN THE FAR SOUTHWESTERN
ZONES...ANY STORMS THAT DO DEVELOP WOULD HAVE THE POTENTIAL TO
BECOME STRONG. THERE IS ALSO POOR AGREEMENT WITH THE MODELS AS THE
GFS IS SOMEWHAT MORE BULLISH AND THE NAM/ECMWF SHOWING LESS IN THE
WAY OF QPF...ALTHOUGH CAPE AND SOME OF THE CONVECTIVE PARAMETERS
DO POINT TO SOME OPPORTUNITY. WILL KEEP THE ENTIRE CWA IN A SLIGHT
CHANCE...WITH LOW END CHANCE POPS IN THE SOUTH COINCIDENT WITH THE
HIGHER CAPE/INSTABILITY. GIVEN POTENTIAL DRYING EFFECT FROM
NORTHWEST FLOW ALOFT AND SUBSIDENCE FROM THE RIDGE...CONVECTION
SHOULD BE ISOLATED IN NATURE. HOWEVER...WITH MID LEVEL DRY
AIR...GOOD DIRECTIONAL SHEAR...AND ABUNDANT CAPE...CANNOT RULE OUT
ONE OR TWO SEVERE STORMS IF CONVECTION INITIATION GETS GOING...ESPECIALLY
IN THE FAR SOUTHERN ZONES.
SUNDAY...THE SYNOPTIC PATTERN WILL EXHIBIT VERY LITTLE CHANGE BUT THE
RIDGE AXIS IS EXPECTED TO TRANSLATE FURTHER EAST AND CLOSER TO THE CWA.
THIS SHOULD PROMOTE LARGE SCALE SUBSIDENCE AND SHOULD KEEP CONVECTIVE
POTENTIAL VERY LIMITED. WILL NOT RULE OUT AN ISOLATED SHOWER OR
STORM DUE TO DIURNAL HEATING BUT WITH LACK OF INSTABILITY PRESENT
STORMS SHOULD NOT BECOME STRONG. TEMPERATURES ARE EXPECTED TO
REMAIN SEASONABLY COOL AS COMPARED TO AVERAGES FOR AUGUST...HOWEVER
WITH THE RIDGE BUILDING IN LATER IN THE WEEKEND...RISING HEIGHTS
WOULD FAVOR A SLOW MODERATING TREND. MUCH OF THE CWA WILL RETURN
TO SEEING HIGHS IN THE 80S BY SUNDAY. MALIAWCO
.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...
MODELS CONTINUE TO ADVERTISE A BIT WITH INCREASED INSTABILITY ABOUT
MIDWEEK. IT MAY BE A BIT EARLY BUT WENT AHEAD AND MADE MENTION OF IT
IN THE HWO. REST OF FORECAST LOOKED GOOD. MODELS ARE BEGINNING TO
SHOW SIGNS OF A STRONGER RIDGE OF HIGH PRESSURE FOR LATE NEXT
WEEK...RESULTING IN TEMPERATURES THAT MAY HIT 90 IN PLACES. TFJ
PREVIOUS DISCUSSION...
THE LONG TERM FORECAST PERIOD IS CHARACTERIZED BY A VERY GRADUAL
BUT CONSISTENTLY STRENGTHENING UPPER LEVEL RIDGE ACROSS THE ROCKY
MOUNTAIN AND HIGH PLAINS REGIONS. THIS WILL SLOWLY PUSH THE LOW
PRESSURE SYSTEM OVER THE PACIFIC NORTHWEST COAST FURTHER NORTH
BEFORE IT JOINS WITH THE LARGER SCALE LOW PRESSURE SYSTEM FROM THE
GULF OF ALASKA BY MID WEEK.
THE SPLIT FLOW OVER THE ROCKY MOUNTAINS QUICKLY REJOINS ON THE LEE
SIDE. THIS IS WHERE THE FORECAST GETS A LITTLE DIFFICULT. BY
THURSDAY OVER MONTANA...THE UPPER LEVEL FLOW SHOWS MORE ZONAL WITH
SOME SUBTLE...UNCERTAIN...AND SMALL SCALE DISTURBANCES TRYING TO
MAKE THEIR WAY THROUGH THE SPLIT FLOW.
MODEL OUTPUTS ALSO INDICATE THE FORECAST COMPLEXITIES WITH THIS BY
CONTINUING TO SHOW DIFFERING SOLUTIONS. GENERALLY SPEAKING...WHERE
THE GFS SHOWS DRY...THE EC SHOWS WET AND VICE VERSA.
GRANTED...LARGE SCALE FORCING FOR ASCENT SHOWS VIRTUALLY NO
ACTIVITY WHAT SO EVER. SO IF ANY PRECIPITATION SYSTEMS MOVE
THROUGH THE REGION...THE IMPACTS ARE EXPECTED TO BE MINIMAL WITH
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS FROM TIME TO TIME.
TEMPERATURES ARE EXPECTED TO GRADUALLY WARM TO NEAR NORMAL LEVELS
FOR THIS TIME OF YEAR. BMICKELSON
&&
.AVIATION...
VFR. A MIDLEVEL RIDGE WILL GENERATE DRY CONDITIONS AND LIGHT
SURFACE WINDS GIVING GOOD FLYING CONDITIONS THROUGH THE NEXT 24
HOURS. HIGH CLOUDS FROM THUNDERSTORMS TO OUR SOUTHWEST SHOULD BE
ALL THAT MOVES IN LATER TONIGHT. EAST WINDS WILL REMAIN LIGHT.
STORMS LATE SATURDAY COULD MOVE A BIT CLOSER...BUT NOT ENOUGH TO
AFFECT FLIGHT OPERATIONS. TFJ/WJM
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
905 AM MDT THU AUG 8 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH SATURDAY...
FAIRLY QUIET AND RELATIVELY STABLE ATMOSPHERE OVER THE REGION THIS
MORNING. DOESN/T LOOK LIKE SHOWER/THUNDERSTORM ACTIVITY THIS MORNING
WILL BE GENERATED SO REMOVED THEM...BUT DID EXPAND A BIT ACROSS THE
NORTHERN ZONES FOR THE AFTERNOON. WILL AGAIN LEAN ON THE HRRR AND
RAP (RUC) MODELS AS THEY HAVE DONE BETTER AS OF LATE. TFJ
PREVIOUS DISCUSSION...
NORTHWEST FLOW ALOFT WILL CONTINUE TODAY WITH DEEP UPPER LOW OVER
WESTERN ONTARIO AND UPPER RIDGE OVER IDAHO. SHORTWAVE TROUGH OVER
SOUTHERN ALBERTA IS BRING SOME SHOWERS AND THUNDERSTORMS TO THAT
AREA AND TO A LESSER DEGREE NORTH CENTRAL MONTANA. THE SHOWERS
HAVE BEEN DISSIPATING WHEN THEY GET TO THE HAVRE AREA OVERNIGHT.
HOWEVER... WITH THE WAVE MOVING TO THE EAST... A FEW OF THESE
SHOWERS/T-STORMS COULD MAKE INTO THE NORTHERN PARTS OF THE
FORECAST AREA THIS MORNING. WILL MENTION ISOLATED SHOWERS AND
THUNDERSTORMS. SURFACE HIGH BUILDS INTO THE AREA FROM THE NORTH
THIS AFTERNOON WITH DRY WEATHER.
THE UPPER LOW MOVES TO THE EAST TONIGHT AND FRIDAY AND UPPER RIDGE
BUILDS INTO MONTANA. WITH AN UPPER TROUGH/CUT OFF LOW OVER
CALIFORNIA...SOUTHERLY FLOW ALOFT TO THE SOUTH OF MONTANA WILL
ALLOW MONSOONAL MOISTURE TO ADVECT NORTH INTO THE STATE. THIS
MOISTURE WILL MAKE INTO THE SOUTHERN ZONES FRIDAY AFTERNOON AND
SPREAD INTO THE ENTIRE FORECAST AREA FRIDAY NIGHT. THE SHOWERS AND
THUNDERSTORMS WILL BE SPOTTY SO WILL MENTION A CHANCE OR SLIGHT
CHANCE.
THE RIDGE CONTINUES TO BUILD INTO MONTANA ON SATURDAY WITH
SOMEWHAT WARMER TEMPERATURES. UNSTABLE AIRMASS WILL COMBINE WITH
WEAK FRONTAL BOUNDARY AND LINGERING MONSOONAL MOISTURE FOR A
SLIGHT CHANCE OF THUNDERSTORMS. FORRESTER
.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY...
SYNOPTIC SET UP...A LARGE BROAD COOL CORE TROUGH EXISTS OVER THE
HUDSON BAY AND THE CANADIAN SHIELD AND PRAIRIES. A LARGE HIGH
PRESSURE HEAT DOME RESIDES OVER THE SOUTHERN AND CENTRAL PLAINS...
THE DESERT SOUTHWEST... AND INTERMOUNTAIN WEST. A RIDGE JUTS OUT OF
THIS DOME THROUGH NORTHERN IDAHO INTO BRITISH COLUMBIA. NORTHEAST
MONTANA LIES BETWEEN THESE TWO FEATURES IN ZONAL TO NORTHWEST
FLOW. TO THE WEST A TROUGH IS STEPPING ON SHORE OF NORTHERN
CALIFORNIA AND IS PUMPING SHORTWAVES INTO THE FLOW TOWARD MONTANA
AND MONSOONAL MOISTURE INTO THE DESERT SOUTHWEST AND INTERMOUNTAIN
WEST WHICH WILL CLIP SOUTHERN MONTANA.
SATURDAY NIGHT THROUGH MONDAY...FLOW ALOFT WILL BECOME NORTHWEST
WHILE THE RIDGE TO THE EAST SLOWLY ACCUMULATES MORE MOISTURE AND
MIGRATES EASTWARD INTO CENTRAL MONTANA. SLIGHT CHANCE TO CHANCE
POPS FOR AFTERNOON THUNDER COULD INITIATED ALONG A SURFACE BOUNDARY
ORIENTED NORTHWEST TO SOUTHEAST ACROSS CENTRAL AND EASTERN
MONTANA AND THEN FURTHER CONTINUED OVERNIGHT AS AIR-MASS
THUNDERSTORM DYNAMICS FED BY MONSOONAL MOISTURE TAKE OVER.
TEMPERATURES SHOULD ALSO BE TICKING UP SLOWLY. THE ONLY QUESTION
IS WHERE IS THE SURFACE BOUNDARY DRIFTING AT ANY PARTICULAR TIME.
MONDAY NIGHT TO WEDNESDAY... THE TROUGH TO THE WEST WILL MOVE
NORTH UP THE COAST OF THE PACIFIC NORTHWEST AND BRITISH COLUMBIA
AND ALLOW THE MAIN RIDGE AXIS TO MOVE EAST ACROSS MONTANA. THE TOP
OF THE RIDGE WILL BE BLUNTED AROUND THE INTERNATIONAL BORDER AND
ALLOW A FEW SHORTWAVES TO PASS BY. THIS WILL CONTINUE THE CHANCES
FOR RAIN SHOWERS EACH AFTERNOON AND OVERNIGHT PERIOD BUT FROM A
SLIGHTLY DIFFERENT LIFT MECHANISM AS THE OLD SURFACE BOUNDARY
MOVES OFF TO THE EAST AND A LEE SURFACE TROUGH TAKES OVER THE ROLE
OF AFTERNOON INITIATION.
WEDNESDAY NIGHT ONWARD... SOME DISCREPANCIES BETWEEN THE MODELS
BEGIN TO PRESENT THEMSELVES HERE AND THEREFORE DECREASE
CONFIDENCE. MAIN ISSUE IS WITH THE RIDGE BROADENING OVER THE
CANADIAN ROCKIES AND PLAINS. THIS IS A COMMON WARMING SUMMER
OCCURRENCE. HOWEVER... THIS YEAR HAS BEEN LESS THAN COMMON WITH FAR
COOLER CONDITIONS. EC AND GEM HAVE TYPICALLY CAUGHT ONTO THIS
WHERE THE GFS HAS FAILED OVER THE LAST MONTH. YET AGAIN... WE GET
A GFS THAT IS GUNG HO ON A VERY SOLID WARMING RIDGE WHILE THE EC
ENSEMBLES ALONG WITH THE UKMET... GEM... AND NOGAPS MEMBERS
LITERALLY POKE HOLES IN THE RIDGE TO THE NORTH WITH EMBEDDED
TROUGHS AND COLD CLOSED LOWS. AT THIS TIME FAR MORE LIKELY TO
BELIEVE THE OTHER MODELS AND PREDICT SOME WEAK COOLER AIR DROPPING
BACK DOWN THAN A DRAMATIC WARM UP... OR AT LEAST KEEPING
TEMPERATURES TRENDING STABLE THIS FAR OUT.
GAH
&&
.AVIATION...
VFR CEILINGS AND VISIBILITIES ARE ANTICIPATED AT THE TERMINALS
THROUGH THE TAF PERIOD. EAST TO NORTHEAST WINDS ARE EXPECTED TO
RANGE AROUND 10 KTS THROUGH THE PERIOD AS WELL. MALIAWCO
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS HASTINGS NE
941 PM CDT FRI AUG 9 2013
.UPDATE...
ISSUED AT 941 PM CDT FRI AUG 9 2013
TRIMMED BACK POPS FOR THE TONIGHT PERIOD...MAINLY TO AREAS
CONFINED TO OUR NORTHWESTERN COUNTIES. THESE SHOWERS SHOULD N0T
LAST PAST MIDNIGHT AS MESOSCALE ANALYSIS INDICATES AN INCREASE IN
CAPPING ACROSS AREAS WHERE CURRENT THUNDERSTORM ACTIVITY IS
ONGOING. ALSO TRIMMED BACK THE PATCHY FOG TO ACCOUNT FOR INCREASE
CLOUD COVER ACROSS OUR NORTH...WHICH SHOULD INHIBIT FOG IN THESE
AREAS. THE PATCHY FOG STILL INCLUDES THE TRI-CITIES AND AREAS
SOUTH OF I-80...WITH A TIME FRAME FROM ROUGHLY 08Z TO 13Z THIS
MORNING.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 345 PM CDT FRI AUG 9 2013
THE PRIMARY ISSUES DURING THE NEXT 24 HOURS INVOLVES ISOLATED AND
LIKELY NON-SEVERE SHOWER/STORM DEVELOPMENT INTO THIS
EVENING...AND WHETHER OR NOT ANY IMPACTFUL FOG MIGHT DEVELOP AGAIN
OVERNIGHT. HAVE MAINTAINED A SHOWER/STORM-FREE FORECAST CWA-WIDE
FROM LATE THIS EVENING THROUGH SATURDAY AFTERNOON.
20Z OBJECTIVE SURFACE ANALYSIS REVEALS A VERY SUBTLE...WEAK COLD
FRONT ALIGNED GENERALLY EAST-WEST ACROSS THE HEART OF THE NEB
CWA...ALTHOUGH ONE HAS TO LOOK PRETTY TO FIND IT...AS ALL IT
REALLY DOES IS SEPARATE A LIGHT EAST-NORTHEAST BREEZE FROM A LIGHT
EAST TO EAST-SOUTHEAST ONE. THIS LIGHT FLOW WITH SUSTAINED BREEZES
MOST ALL AREAS NO MORE THAN 5-10 MPH IS A RESULT OF BROAD SURFACE
HIGH PRESSURE OVER THE REGION...WITH THE CORE OF THE PARENT HIGH
AROUND 1027 MILLIBARS CENTERED WELL TO THE NORTH OVER
SASKATCHEWAN. ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL
DATA REVEALS RATHER WEAK FLOW ALOFT OVER THE CWA...GENERALLY
WESTERLY UP AT 300MB...NORTHERLY AT 500 MB...AND EVEN FARTHER DOWN
FROM THE EAST-NORTHEAST AT 700MB. ON THE LARGE SCALE...THE CENTRAL
PLAINS LIES IN THE INTERFACE BETWEEN A BROAD TROUGH AND EMBEDDED
VIGOROUS SHORTWAVE TRACKING EAST ACROSS SOUTHEAST CANADA...AND A
RIDGE AXIS EXTENDING EAST-WEST ACROSS THE SOUTHERN CONUS AND THEN
NORTHWARD INTO THE ROCKIES. ON A MORE REGIONAL LEVEL...A LOW-
AMPLITUDE MID LEVEL DISTURBANCE IS LIFTING OUT ACROSS EASTERN
KS/WESTERN MO. OTHER VERY SUBTLE DISTURBANCES APPEAR TO BE
RIPPLING OUT OF THE WY AREA TOWARD WESTERN NEB/SOUTHWEST SD...AND
HELPING TO KICK OFF STORMS IN THE NORTHERN PANHANDLE.
LOCALLY...JUST WITHIN THE PAST HOUR A FEW SMALL...ISOLATED
SHOWERS/POSSIBLY WEAK STORMS HAVE BUBBLED UP OVER DAWSON/BUFFALO
COUNTIES BUT HAVE SHOWED LITTLE SIGN OF MAINTAINING ORGANIZATION.
VISIBLE SATELLITE REVEALS PARTLY TO MOSTLY CLOUDY SKIES OVER THE
CWA AT MID-AFTERNOON...WITH A DECENT LOW LEVEL CUMULUS FIELD
ACROSS MUCH OF THE CENTRAL/WEST...AND SOME LINGERING HIGH CIRRUS
STILL GRADUALLY DEPARTING EASTERN COUNTIES. HIGH TEMPS APPEAR TO
BE FAIRLY WELL ON TRACK...WITH MOST AREAS LIKELY TO END UP IN THE
81-84 RANGE.
GOING FORWARD THROUGH THE LATE AFTERNOON HOURS THROUGH
03Z/10PM...HAVE OPTED TO KEEP THINGS SIMPLE AND ADVERTISE A SLIGHT
CHANCE OF SHOWERS/ISOLATED THUNDERSTORMS CWA-WIDE...ALTHOUGH WOULD
ANTICIPATE THE MOST LIKELY LOCALIZED DEVELOPMENT TO CONTINUE
TARGETING THE WESTERN HALF OF THE NEB CWA...WHERE LATEST MESO-
ANALYSIS INDICATES 0-1KM MLCAPE UP TO AROUND 1500 J/KG...AND WITH
LITTLE IF ANY CINH BUT ALSO VERY LIMITED FORCING FOR ASCENT. WITH
DEEP-LAYER SHEAR AVERAGING NO MORE THAN 15-20KT AND MID LEVEL
LAPSE RATES RATHER SHALLOW AT ONLY 5-6 C/KM...THE THREAT FOR
STRONG TO SEVERE STORMS APPEARS TO BE QUITE LIMITED IF NOT NON-
EXISTENT. POST-03Z/10PM...WILL AIM FOR A DRY REST OF THE
NIGHT...AS ANY DIURNAL SUPPORT FOR CONVECTION FROM AFTERNOON
HEATING WILL BE ON THE WANE...AND GIVEN THAT THE MAIN TRACK OF LOW
AMPLITUDE MID LEVEL DISTURBANCES OVERNIGHT SHOULD GENERALLY TARGET
THE NEB/SD BORDER AREA. FURTHERMORE...THE NOSE OF A MODEST 35KT
850MB LOW LEVEL JET CLEARLY AIMS INTO SOUTHERN SD/FAR NORTH CENTRAL
NEB OVERNIGHT...WHICH IS WHERE MOST MODELS INCLUDING THE NAM AND
4M WRF-NMM FOCUS CONVECTION. THAT BEING SAID...WILL HAVE TO KEEP
AN EYE ON THE NORTHWEST CWA AS THE LATEST HRRR MAINTAINS SOME
SANDHILLS CONVECTION WITHIN 50 MILES OF THE CWA THROUGH AROUND
MIDNIGHT...BUT FEEL THIS MAY BE A BIT CLOSER TO HOME THAN IT
ACTUALLY WILL BE. AT THE SURFACE TONIGHT...BREEZES WILL REMAIN
QUITE LIGHT AND AVERAGE UNDER 5 MPH...WHILE GRADUALLY TURNING TO A
SOUTHERLY DIRECTION. GIVEN THE LIGHT WIND SETUP...THERE IS AT
LEAST SOME CONCERN THAT FOG COULD AGAIN DEVELOP AND REDUCE
VISIBILITY TO 1 MILE OR LESS. HOWEVER...THE CONSENSUS OF
MODELS/GUIDANCE IS THAT TONIGHT/S FOG EVENT SHOULDN/T BE AS
DENSE/IMPACTFUL...POSSIBLY DUE TO SLIGHTLY BETTER BETTER MIXING
JUST ABOVE THE SURFACE. FOR NOW...WILL MAINTAIN THE GENERIC PATCHY
FOG MENTION CWA-WIDE FOR THE LATE NIGHT/EARLY MORNING HOURS
INTRODUCED BY THE PREVIOUS SHIFT...BUT WILL DEFER TO THE NEXT FEW
SHIFTS TO POTENTIALLY RAMP UP THIS FOG WORDING IF NEED BE. AS FOR
LOW TEMPS...ACTUALLY NUDGED DOWN 1-2 DEGREES FROM PREVIOUS IN MOST
SPOTS PER A GUIDANCE BLEND...WHICH PUTS MOST AREAS DOWN BETWEEN
57-61 DEGREES.
TURNING TO THE SATURDAY DAYTIME PERIOD 12Z-00Z/7AM-7PM...MAINTAINED
A RAIN-FREE FORECAST CWA-WIDE. IN THE MID/UPPER LEVELS...FAIRLY
WEAK TO MODEST WEST-NORTHWEST FLOW WILL MAINTAIN OVER THE CENTRAL
PLAINS AT/ABOVE 500MB...AND THERE SHOULD BE SOME SUBTLE HEIGHT
RISES AS WELL...AS THE SOUTHERN PLAINS/SOUTHERN ROCKIES RIDGE
EDGES NORTH JUST A BIT. THE PRIMARY MID LEVEL SHORTWAVE TROUGH
TRACK DURING THE DAY WILL BE FROM SD TOWARD SOUTHWEST MN/NORTHWEST
IA...AND THIS DISTURBANCE SHOULD TEAM WITH AN EAST-WEST QUASI-
STATIONARY FRONT SETTING UP NEAR THE NEB/SD BORDER TO FOCUS THE
VAST MAJORITY OF DAYTIME CONVECTION AT LEAST 50-100 MILES NORTH
AND POSSIBLY NORTHWEST OF THE CWA. THE ODDS OF CONVECTION FORMING
LOCALLY WITH DAYTIME HEATING SEEMS SMALLER THAN TODAY GIVEN
SLIGHTLY WARMER TEMPS EVIDENT AT 700MB...DESPITE MODEST MLCAPE
VALUES CLIMBING INTO THE 500-1000 J/KG RANGE PER THE 18Z NAM.
MODEL FORECASTS SOUNDINGS ALSO CLEARLY SHOW A WEAK BUT EVIDENT CAP.
OTHERWISE...ALTHOUGH BY NO MEANS WINDY...THE LATE MORNING-
AFTERNOON HOURS SHOULD FEATURE SOME OF THE MOST NOTICEABLE MODEST
BREEZES FELT IN MOST OF THE CWA IN SEVERAL DAYS...AS A TIGHTENED
PRESSURE GRADIENT TO THE EAST OF HIGH PLAINS LEE TROUGH SHOULD
PROMOTE SUSTAINED SOUTHERLY SPEEDS 10-15 MPH MOST AREAS. GIVEN THE
SOUTHERLY BREEZES...SLIGHTLY WARMER TEMPS AT 850MB...AND LIKELY NO
WORSE THAN PARTLY CLOUDY SKIES...SEE LITTLE REASON WHY HIGH TEMPS
SHOULDN/T BE AT LEAST A TOUCH HIGHER THAN TODAY. AS A
RESULT...NUDGED UP PREVIOUS HIGHS 1-2 DEGREES IN MOST AREAS...WITH
MOST OF THE CWA AIMED FOR FAIRLY UNIFORM HIGHS BETWEEN 83-86
DEGREES.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 344 PM CDT FRI AUG 9 2013
GUIDANCE SUGGESTS QUASI-ZONAL TO NORTHWESTERLY MID TO UPPER LEVEL
FLOW WILL PERSIST OVER THE CENTRAL PLAINS THROUGH MUCH OF THE LONG
TERM FORECAST PERIOD...WITH THE POSSIBILITY OF MULTIPLE MID LEVEL
PERTURBATIONS MOVING OVER THE AREA. PRECIPITATION CHANCES REMAIN
INTACT THROUGHOUT THE LONG TERM FORECAST PERIOD AS A RESULT.
STARTING SATURDAY NIGHT...THERE ARE SIGNS...PRIMARILY FROM THE
EC...OPERATIONAL GFS AND SREF-MEAN...THAT CENTRAL TO NORTHERN HIGH
PLAINS CONVECTION FROM SATURDAY AFTERNOON/EVENING MAY HOLD TOGETHER
LONG ENOUGH...PRIMARILY DUE TO LOW LEVEL THERMAL ADVECTION ALONG THE
AXIS OF A ~30KT 850MB JET STREAK...TO IMPACT NORTHERN PORTIONS OF
OUR CWA. CONFIDENCE IS NOT OVERLY HIGH THAT MEASURABLE PRECIPITATION
WILL BE REALIZED ACROSS OUR AREA SATURDAY NIGHT AND AS A
RESULT...POPS ONLY IN THE 20-30% RANGE CURRENTLY EXIST. HEADING INTO
THE DAY SUNDAY...LOW LEVEL CONVERGENCE ALONG A LOW LEVEL BAROCLINIC
ZONE/TROUGH COULD PROMOTE ENOUGH LIFT...ALONG WITH A PASSING MID
LEVEL PERTURBATION...TO PROMOTE PRECIPITATION PRODUCTION ACROSS
PORTIONS OF THE REGION. WHERE EXACTLY THE BOUNDARY POSITIONS ITSELF
IS THE BIGGEST QUESTION AT THIS TIME. THE NAM...EC...AND SREF-MEAN
ALL SUGGEST THE BOUNDARY WILL MOVE INTO NORTHERN OR CENTRAL PORTIONS
OF OUR CWA...WHILE THE OPERATIONAL GFS KEEPS THE BOUNDARY TO THE NORTH OF
OUR AREA. GIVEN THE UNCERTAINTY WITH RESPECT TO BOUNDARY
LOCATION...WENT NO HIGHER THAN 20-30% FOR THE DAY SUNDAY. CHANCES
FOR PRECIPITATION...ALBEIT LOW CHANCES DUE TO LOW CONFIDENCE...THEN
CONTINUE ACROSS MUCH OF OUR AREA SUNDAY NIGHT AS THE AXIS OF A
25-30KT 850MB JET STREAK DEVELOPS AND YET ANOTHER MID LEVEL
PERTURBATION POTENTIALLY MOVES OVER PORTIONS OF THE REGION. 20-30%
POPS REMAIN INTACT ACROSS THE AREA SUNDAY NIGHT AS A RESULT.
FINALLY...DURING THE DAY MONDAY...YET ANOTHER WEAK MID LEVEL
PERTURBATION MAY MOVE OVER THE AREA. CONFIDENCE IS LOW WITH RESPECT
TO ANY ONE LOCATION ACROSS THE AREA RECEIVING MEASURABLE
PRECIPITATION BUT RATHER THAN ELIMINATE POPS...WENT AHEAD AND
PRESENTED MOSTLY ~20% POPS TO MUCH OF OUR AREA FOR MONDAY.
MID LEVEL PERTURBATIONS MOVING OVER THE AREA WILL ALSO PROMOTE
CHANCES FOR PRECIPITATION ACROSS OUR AREA MONDAY NIGHT ONWARD AND AS
A RESULT...ALLBLEND PRESENTED POPS RANGING ANYWHERE FROM 20% TO 50%.
AFTER COORDINATION WITH SURROUNDING OFFICES...A FEW MINOR TWEAKS
WERE MADE TO TUESDAY POPS. OTHERWISE...ALLBLEND POPS WERE LEFT
UNCHANGED FOR THE MOST PART DUE TO THE LOW PROBABILITY OF IMPROVING
ON THE ALLBLEND SOLUTION.
DECENT LOW LEVEL MOISTURE...WITH SURFACE DEWPOINTS IN THE UPPER 60S
TO NEAR 70...WILL HELP PROMOTE RESPECTABLE LEVELS OF POTENTIAL
INSTABILITY BOTH SUNDAY AND MONDAY...WITH THE NAM AND OPERATIONAL GFS
BOTH SUGGESTING MUCAPE VALUES IN THE 2500-3500J/KG RANGE. DEEP LAYER
BULK SHEAR DOES NOT APPEAR AS THOUGH IT WILL BE OVERLY
IMPRESSIVE...GENERALLY IN THE 20-25KT RANGE...BUT GIVEN THE EXPECTED
POTENTIAL INSTABILITY WILL GO AHEAD AND OUTLOOK STRONG TO SEVERE
STORMS IN THE HWO FOR SUNDAY AND MONDAY. A SOMEWHAT DRIER LOW LEVEL
AIRMASS IS THEN EXPECTED TO INFILTRATE THE AREA TUESDAY ONWARD THUS
RESULTING IN LOWER POTENTIAL INSTABILITY VALUES. AS A RESULT...WILL
REFRAIN FROM ANY STRONG/SEVERE WEATHER WORDING IN THE HWO TUESDAY
AND BEYOND.
&&
.AVIATION...(FOR THE 00Z KGRI TAF THROUGH 00Z SATURDAY EVENING)
ISSUED AT 640 PM CDT FRI AUG 9 2013
VFR CONDITIONS ARE EXPECTED TO CONTINUE AT KGRI FOR THE NEXT
SEVERAL HOURS AS TSRA DEVELOPMENT THIS AFTERNOON HAS BEEN VERY
ISOLATED. HOWEVER AS THE SUN SETS AND SKIES CLEAR THIS
EVENING...EXPECT THE POTENTIAL FOR FOG DEVELOPMENT NEAR THE
TERMINAL...AND DECIDED TO INTRODUCE SOME LIFR CIGS AND MVFR VSBYS
JUST BEFORE SUNRISE TO ACCOUNT FOR THIS. OTHERWISE...ANY FOG THAT
DOES DEVELOP IS EXPECTED TO BE SHORT LIVED...AS LIGHT WINDS
OVERNIGHT WILL BE REPLACED BY SOUTHERLY WINDS NEAR 10KTS AROUND
10/13-10/14Z...WHICH WILL HELP SCOUR OUT THE FOG AND RESULT IN VFR
VSBYS AND CIGS FOR THE REMAINDER OF THE TAF PERIOD.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...GUERRERO
SHORT TERM...PFANNKUCH
LONG TERM...BRYANT
AVIATION...SAR
AREA FORECAST DISCUSSION
NWS HASTINGS NE
646 PM CDT FRI AUG 9 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 345 PM CDT FRI AUG 9 2013
THE PRIMARY ISSUES DURING THE NEXT 24 HOURS INVOLVES ISOLATED AND
LIKELY NON-SEVERE SHOWER/STORM DEVELOPMENT INTO THIS
EVENING...AND WHETHER OR NOT ANY IMPACTFUL FOG MIGHT DEVELOP AGAIN
OVERNIGHT. HAVE MAINTAINED A SHOWER/STORM-FREE FORECAST CWA-WIDE
FROM LATE THIS EVENING THROUGH SATURDAY AFTERNOON.
20Z OBJECTIVE SURFACE ANALYSIS REVEALS A VERY SUBTLE...WEAK COLD
FRONT ALIGNED GENERALLY EAST-WEST ACROSS THE HEART OF THE NEB
CWA...ALTHOUGH ONE HAS TO LOOK PRETTY TO FIND IT...AS ALL IT
REALLY DOES IS SEPARATE A LIGHT EAST-NORTHEAST BREEZE FROM A LIGHT
EAST TO EAST-SOUTHEAST ONE. THIS LIGHT FLOW WITH SUSTAINED BREEZES
MOST ALL AREAS NO MORE THAN 5-10 MPH IS A RESULT OF BROAD SURFACE
HIGH PRESSURE OVER THE REGION...WITH THE CORE OF THE PARENT HIGH
AROUND 1027 MILLIBARS CENTERED WELL TO THE NORTH OVER
SASKATCHEWAN. ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL
DATA REVEALS RATHER WEAK FLOW ALOFT OVER THE CWA...GENERALLY
WESTERLY UP AT 300MB...NORTHERLY AT 500 MB...AND EVEN FARTHER DOWN
FROM THE EAST-NORTHEAST AT 700MB. ON THE LARGE SCALE...THE CENTRAL
PLAINS LIES IN THE INTERFACE BETWEEN A BROAD TROUGH AND EMBEDDED
VIGOROUS SHORTWAVE TRACKING EAST ACROSS SOUTHEAST CANADA...AND A
RIDGE AXIS EXTENDING EAST-WEST ACROSS THE SOUTHERN CONUS AND THEN
NORTHWARD INTO THE ROCKIES. ON A MORE REGIONAL LEVEL...A LOW-
AMPLITUDE MID LEVEL DISTURBANCE IS LIFTING OUT ACROSS EASTERN
KS/WESTERN MO. OTHER VERY SUBTLE DISTURBANCES APPEAR TO BE
RIPPLING OUT OF THE WY AREA TOWARD WESTERN NEB/SOUTHWEST SD...AND
HELPING TO KICK OFF STORMS IN THE NORTHERN PANHANDLE.
LOCALLY...JUST WITHIN THE PAST HOUR A FEW SMALL...ISOLATED
SHOWERS/POSSIBLY WEAK STORMS HAVE BUBBLED UP OVER DAWSON/BUFFALO
COUNTIES BUT HAVE SHOWED LITTLE SIGN OF MAINTAINING ORGANIZATION.
VISIBLE SATELLITE REVEALS PARTLY TO MOSTLY CLOUDY SKIES OVER THE
CWA AT MID-AFTERNOON...WITH A DECENT LOW LEVEL CUMULUS FIELD
ACROSS MUCH OF THE CENTRAL/WEST...AND SOME LINGERING HIGH CIRRUS
STILL GRADUALLY DEPARTING EASTERN COUNTIES. HIGH TEMPS APPEAR TO
BE FAIRLY WELL ON TRACK...WITH MOST AREAS LIKELY TO END UP IN THE
81-84 RANGE.
GOING FORWARD THROUGH THE LATE AFTERNOON HOURS THROUGH
03Z/10PM...HAVE OPTED TO KEEP THINGS SIMPLE AND ADVERTISE A SLIGHT
CHANCE OF SHOWERS/ISOLATED THUNDERSTORMS CWA-WIDE...ALTHOUGH WOULD
ANTICIPATE THE MOST LIKELY LOCALIZED DEVELOPMENT TO CONTINUE
TARGETING THE WESTERN HALF OF THE NEB CWA...WHERE LATEST MESO-
ANALYSIS INDICATES 0-1KM MLCAPE UP TO AROUND 1500 J/KG...AND WITH
LITTLE IF ANY CINH BUT ALSO VERY LIMITED FORCING FOR ASCENT. WITH
DEEP-LAYER SHEAR AVERAGING NO MORE THAN 15-20KT AND MID LEVEL
LAPSE RATES RATHER SHALLOW AT ONLY 5-6 C/KM...THE THREAT FOR
STRONG TO SEVERE STORMS APPEARS TO BE QUITE LIMITED IF NOT NON-
EXISTENT. POST-03Z/10PM...WILL AIM FOR A DRY REST OF THE
NIGHT...AS ANY DIURNAL SUPPORT FOR CONVECTION FROM AFTERNOON
HEATING WILL BE ON THE WANE...AND GIVEN THAT THE MAIN TRACK OF LOW
AMPLITUDE MID LEVEL DISTURBANCES OVERNIGHT SHOULD GENERALLY TARGET
THE NEB/SD BORDER AREA. FURTHERMORE...THE NOSE OF A MODEST 35KT
850MB LOW LEVEL JET CLEARLY AIMS INTO SOUTHERN SD/FAR NORTH CENTRAL
NEB OVERNIGHT...WHICH IS WHERE MOST MODELS INCLUDING THE NAM AND
4M WRF-NMM FOCUS CONVECTION. THAT BEING SAID...WILL HAVE TO KEEP
AN EYE ON THE NORTHWEST CWA AS THE LATEST HRRR MAINTAINS SOME
SANDHILLS CONVECTION WITHIN 50 MILES OF THE CWA THROUGH AROUND
MIDNIGHT...BUT FEEL THIS MAY BE A BIT CLOSER TO HOME THAN IT
ACTUALLY WILL BE. AT THE SURFACE TONIGHT...BREEZES WILL REMAIN
QUITE LIGHT AND AVERAGE UNDER 5 MPH...WHILE GRADUALLY TURNING TO A
SOUTHERLY DIRECTION. GIVEN THE LIGHT WIND SETUP...THERE IS AT
LEAST SOME CONCERN THAT FOG COULD AGAIN DEVELOP AND REDUCE
VISIBILITY TO 1 MILE OR LESS. HOWEVER...THE CONSENSUS OF
MODELS/GUIDANCE IS THAT TONIGHT/S FOG EVENT SHOULDN/T BE AS
DENSE/IMPACTFUL...POSSIBLY DUE TO SLIGHTLY BETTER BETTER MIXING
JUST ABOVE THE SURFACE. FOR NOW...WILL MAINTAIN THE GENERIC PATCHY
FOG MENTION CWA-WIDE FOR THE LATE NIGHT/EARLY MORNING HOURS
INTRODUCED BY THE PREVIOUS SHIFT...BUT WILL DEFER TO THE NEXT FEW
SHIFTS TO POTENTIALLY RAMP UP THIS FOG WORDING IF NEED BE. AS FOR
LOW TEMPS...ACTUALLY NUDGED DOWN 1-2 DEGREES FROM PREVIOUS IN MOST
SPOTS PER A GUIDANCE BLEND...WHICH PUTS MOST AREAS DOWN BETWEEN
57-61 DEGREES.
TURNING TO THE SATURDAY DAYTIME PERIOD 12Z-00Z/7AM-7PM...MAINTAINED
A RAIN-FREE FORECAST CWA-WIDE. IN THE MID/UPPER LEVELS...FAIRLY
WEAK TO MODEST WEST-NORTHWEST FLOW WILL MAINTAIN OVER THE CENTRAL
PLAINS AT/ABOVE 500MB...AND THERE SHOULD BE SOME SUBTLE HEIGHT
RISES AS WELL...AS THE SOUTHERN PLAINS/SOUTHERN ROCKIES RIDGE
EDGES NORTH JUST A BIT. THE PRIMARY MID LEVEL SHORTWAVE TROUGH
TRACK DURING THE DAY WILL BE FROM SD TOWARD SOUTHWEST MN/NORTHWEST
IA...AND THIS DISTURBANCE SHOULD TEAM WITH AN EAST-WEST QUASI-
STATIONARY FRONT SETTING UP NEAR THE NEB/SD BORDER TO FOCUS THE
VAST MAJORITY OF DAYTIME CONVECTION AT LEAST 50-100 MILES NORTH
AND POSSIBLY NORTHWEST OF THE CWA. THE ODDS OF CONVECTION FORMING
LOCALLY WITH DAYTIME HEATING SEEMS SMALLER THAN TODAY GIVEN
SLIGHTLY WARMER TEMPS EVIDENT AT 700MB...DESPITE MODEST MLCAPE
VALUES CLIMBING INTO THE 500-1000 J/KG RANGE PER THE 18Z NAM.
MODEL FORECASTS SOUNDINGS ALSO CLEARLY SHOW A WEAK BUT EVIDENT CAP.
OTHERWISE...ALTHOUGH BY NO MEANS WINDY...THE LATE MORNING-
AFTERNOON HOURS SHOULD FEATURE SOME OF THE MOST NOTICEABLE MODEST
BREEZES FELT IN MOST OF THE CWA IN SEVERAL DAYS...AS A TIGHTENED
PRESSURE GRADIENT TO THE EAST OF HIGH PLAINS LEE TROUGH SHOULD
PROMOTE SUSTAINED SOUTHERLY SPEEDS 10-15 MPH MOST AREAS. GIVEN THE
SOUTHERLY BREEZES...SLIGHTLY WARMER TEMPS AT 850MB...AND LIKELY NO
WORSE THAN PARTLY CLOUDY SKIES...SEE LITTLE REASON WHY HIGH TEMPS
SHOULDN/T BE AT LEAST A TOUCH HIGHER THAN TODAY. AS A
RESULT...NUDGED UP PREVIOUS HIGHS 1-2 DEGREES IN MOST AREAS...WITH
MOST OF THE CWA AIMED FOR FAIRLY UNIFORM HIGHS BETWEEN 83-86
DEGREES.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 344 PM CDT FRI AUG 9 2013
GUIDANCE SUGGESTS QUASI-ZONAL TO NORTHWESTERLY MID TO UPPER LEVEL
FLOW WILL PERSIST OVER THE CENTRAL PLAINS THROUGH MUCH OF THE LONG
TERM FORECAST PERIOD...WITH THE POSSIBILITY OF MULTIPLE MID LEVEL
PERTURBATIONS MOVING OVER THE AREA. PRECIPITATION CHANCES REMAIN
INTACT THROUGHOUT THE LONG TERM FORECAST PERIOD AS A RESULT.
STARTING SATURDAY NIGHT...THERE ARE SIGNS...PRIMARILY FROM THE
EC...OPERATIONAL GFS AND SREF-MEAN...THAT CENTRAL TO NORTHERN HIGH
PLAINS CONVECTION FROM SATURDAY AFTERNOON/EVENING MAY HOLD TOGETHER
LONG ENOUGH...PRIMARILY DUE TO LOW LEVEL THERMAL ADVECTION ALONG THE
AXIS OF A ~30KT 850MB JET STREAK...TO IMPACT NORTHERN PORTIONS OF
OUR CWA. CONFIDENCE IS NOT OVERLY HIGH THAT MEASURABLE PRECIPITATION
WILL BE REALIZED ACROSS OUR AREA SATURDAY NIGHT AND AS A
RESULT...POPS ONLY IN THE 20-30% RANGE CURRENTLY EXIST. HEADING INTO
THE DAY SUNDAY...LOW LEVEL CONVERGENCE ALONG A LOW LEVEL BAROCLINIC
ZONE/TROUGH COULD PROMOTE ENOUGH LIFT...ALONG WITH A PASSING MID
LEVEL PERTURBATION...TO PROMOTE PRECIPITATION PRODUCTION ACROSS
PORTIONS OF THE REGION. WHERE EXACTLY THE BOUNDARY POSITIONS ITSELF
IS THE BIGGEST QUESTION AT THIS TIME. THE NAM...EC...AND SREF-MEAN
ALL SUGGEST THE BOUNDARY WILL MOVE INTO NORTHERN OR CENTRAL PORTIONS
OF OUR CWA...WHILE THE OPERATIONAL GFS KEEPS THE BOUNDARY TO THE NORTH OF
OUR AREA. GIVEN THE UNCERTAINTY WITH RESPECT TO BOUNDARY
LOCATION...WENT NO HIGHER THAN 20-30% FOR THE DAY SUNDAY. CHANCES
FOR PRECIPITATION...ALBEIT LOW CHANCES DUE TO LOW CONFIDENCE...THEN
CONTINUE ACROSS MUCH OF OUR AREA SUNDAY NIGHT AS THE AXIS OF A
25-30KT 850MB JET STREAK DEVELOPS AND YET ANOTHER MID LEVEL
PERTURBATION POTENTIALLY MOVES OVER PORTIONS OF THE REGION. 20-30%
POPS REMAIN INTACT ACROSS THE AREA SUNDAY NIGHT AS A RESULT.
FINALLY...DURING THE DAY MONDAY...YET ANOTHER WEAK MID LEVEL
PERTURBATION MAY MOVE OVER THE AREA. CONFIDENCE IS LOW WITH RESPECT
TO ANY ONE LOCATION ACROSS THE AREA RECEIVING MEASURABLE
PRECIPITATION BUT RATHER THAN ELIMINATE POPS...WENT AHEAD AND
PRESENTED MOSTLY ~20% POPS TO MUCH OF OUR AREA FOR MONDAY.
MID LEVEL PERTURBATIONS MOVING OVER THE AREA WILL ALSO PROMOTE
CHANCES FOR PRECIPITATION ACROSS OUR AREA MONDAY NIGHT ONWARD AND AS
A RESULT...ALLBLEND PRESENTED POPS RANGING ANYWHERE FROM 20% TO 50%.
AFTER COORDINATION WITH SURROUNDING OFFICES...A FEW MINOR TWEAKS
WERE MADE TO TUESDAY POPS. OTHERWISE...ALLBLEND POPS WERE LEFT
UNCHANGED FOR THE MOST PART DUE TO THE LOW PROBABILITY OF IMPROVING
ON THE ALLBLEND SOLUTION.
DECENT LOW LEVEL MOISTURE...WITH SURFACE DEWPOINTS IN THE UPPER 60S
TO NEAR 70...WILL HELP PROMOTE RESPECTABLE LEVELS OF POTENTIAL
INSTABILITY BOTH SUNDAY AND MONDAY...WITH THE NAM AND OPERATIONAL GFS
BOTH SUGGESTING MUCAPE VALUES IN THE 2500-3500J/KG RANGE. DEEP LAYER
BULK SHEAR DOES NOT APPEAR AS THOUGH IT WILL BE OVERLY
IMPRESSIVE...GENERALLY IN THE 20-25KT RANGE...BUT GIVEN THE EXPECTED
POTENTIAL INSTABILITY WILL GO AHEAD AND OUTLOOK STRONG TO SEVERE
STORMS IN THE HWO FOR SUNDAY AND MONDAY. A SOMEWHAT DRIER LOW LEVEL
AIRMASS IS THEN EXPECTED TO INFILTRATE THE AREA TUESDAY ONWARD THUS
RESULTING IN LOWER POTENTIAL INSTABILITY VALUES. AS A RESULT...WILL
REFRAIN FROM ANY STRONG/SEVERE WEATHER WORDING IN THE HWO TUESDAY
AND BEYOND.
&&
.AVIATION...(FOR THE 00Z KGRI TAF THROUGH 00Z SATURDAY EVENING)
ISSUED AT 640 PM CDT FRI AUG 9 2013
VFR CONDITIONS ARE EXPECTED TO CONTINUE AT KGRI FOR THE NEXT
SEVERAL HOURS AS TSRA DEVELOPMENT THIS AFTERNOON HAS BEEN VERY
ISOLATED. HOWEVER AS THE SUN SETS AND SKIES CLEAR THIS
EVENING...EXPECT THE POTENTIAL FOR FOG DEVELOPMENT NEAR THE
TERMINAL...AND DECIDED TO INTRODUCE SOME LIFR CIGS AND MVFR VSBYS
JUST BEFORE SUNRISE TO ACCOUNT FOR THIS. OTHERWISE...ANY FOG THAT
DOES DEVELOP IS EXPECTED TO BE SHORT LIVED...AS LIGHT WINDS
OVERNIGHT WILL BE REPLACED BY SOUTHERLY WINDS NEAR 10KTS AROUND
10/13-10/14Z...WHICH WILL HELP SCOUR OUT THE FOG AND RESULT IN VFR
VSBYS AND CIGS FOR THE REMAINDER OF THE TAF PERIOD.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...BRYANT
AVIATION...SAR
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
342 PM CDT THU AUG 8 2013
.DISCUSSION...
MAIN SHORT TERM CONCERN IS POPS THROUGH TONIGHT AS SCATTERED
SHOWERS CONTINUE TO DRIFT EAST ACROSS THE CWA.
LATEST WATER VAPOR IMAGERY AND LATEST RAP 500MB ANALYSIS SHOW A
LARGE UPPER LOW OVER ONTARIO WITH A RIDGE EXTENDING FROM THE FOUR
CORNERS REGION INTO BRITISH COLUMBIA. IN BETWEEN THIS...A WEAK
SHORTWAVE EXTENDS FROM EASTERN NEBRASKA INTO NORTHEAST KANSAS WITH
ANOTHER CIRCULATION IN SOUTH CENTRAL COLORADO.
THE SHORTWAVE ENERGY OVER THE REGION CONTINUES TO SUPPORT AN AREA
OF WIDELY SCATTERED SHOWERS OVER THE FORECAST AREA. THE LATEST RAP
SEEMS TO HAVE A GOOD HANDLE...ALBEIT A BIT OVERDONE ON QPF...AND
HAVE FOLLOWED MORE CLOSELY TO ITS TRENDS. UPPER LEVEL SUPPORT WILL
MOVE OUT OF THE AREA EARLY THIS EVENING SO HAVE ONLY CARRIED A
MENTION OF PCPN THROUGH THIS TIME. DID CONTINUE A MENTION OF SMALL
POPS IN THE FAR SOUTHEAST AFTER 06Z WITH SOME WEAK UPPER LEVEL
SUPPORT REMAINING INTO THE MORNING.
FRIDAY CONTINUES TO LOOK MOSTLY DRY BUT DID KEEP A SMALL POP IN
FOR THE SOUTH WITH SOME WEAK UPPER LEVEL SUPPORT IN THE AREA.
WITH MID/UPPER LEVEL FLOW OUT OF THE NORTHWEST THROUGH THE
WEEKEND...AND INCREASING WAA REGIME...WILL KEEP SOME SCATTERED
POPS ACROSS THE AREA...MAINLY IN THE NORTH. A STRONGER SHORTWAVE
WILL SLIDE ACROSS SOUTH DAKOTA THROUGH THE NORTHWEST FLOW
SATURDAY...SO BEST CHANCES WILL BE IN THE NORTH...ALTHOUGH WE
SHOULD NOTE THAT THE NEW 12Z ECMWF IS TRENDING THIS WAVE A BIT
FARTHER SOUTH.
ON AND OFF AGAIN SHOWERS AND TSTMS CANNOT BE RULED OUT THROUGH THE
EXTENDED WITH WEAK UPPER LEVEL SUPPORT SLIDING THROUGH THE REGION.
&&
.AVIATION...
18Z TAFS FOR KOMA...KLNK AND KOFK.
VFR CONDITIONS ARE EXPECTED TO CONTINUE AT ALL THREE SITES
FOR MUCH OF THE PERIOD. KOFK LIKELY TO SEE SOME PATCHY LIGHT
SHOWERS INTO TONIGHT BUT KOMA AND KLNK SHOULD STAY DRY. A PERIOD
OF MVFR FOG ALSO POSSIBLE AT KOFK TOWARDS DAWN.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BUFFALO NY
314 PM EDT THU AUG 8 2013
.SYNOPSIS...
A WEAK FRONTAL BOUNDARY ACROSS THE AREA WILL PROVIDE FOCUS FOR
SCATTERED SHOWERS AND THUNDERSTORMS THIS EVENING THROUGH EARLY
FRIDAY. THE FRONT WILL MOVE EAST OF THE AREA BY FRIDAY AFTERNOON
AND BRING AN END TO THE RISK OF RAIN FOR A WHILE. A MORE PRONOUNCED
COLD FRONT WILL CROSS THE AREA FRIDAY NIGHT...BUT WILL COME THROUGH
DRY WITH A COOLER AND DRIER AIRMASS FOR THE WEEKEND AS HIGH PRESSURE
BUILDS ACROSS THE GREAT LAKES.
&&
.NEAR TERM /THROUGH FRIDAY/...
THE COLD FRONT WHICH MOVED ACROSS SOUTHERN ONTARIO OVERNIGHT HAS
STALLED AND LAST MOST OF ITS THERMAL CHARACTERISTICS. THE SURFACE
TROUGH AND ASSOCIATED WIND SHIFT REMAINS ACROSS SOUTHERN ONTARIO AND
THE BASINS OF THE EASTERN GREAT LAKES. THERE IS A SURGE IN LOW LEVEL
MOISTURE TO THE EAST OF THE TROUGH...OVER WESTERN AND CENTRAL NEW
YORK...WITH DEWPOINTS RISING BACK TO THE UPPER 60S AND EVEN LOWER
70S.
ISOLATED TO SCATTERED CONVECTION WILL DEVELOP WITHIN THIS AREA OF
LOW LEVEL MOISTURE POOLING TO THE EAST OF THE SURFACE TROUGH...AIDED
BY LAKE BREEZE BOUNDARIES AND OUTFLOW BOUNDARIES FROM ADJACENT
COLLAPSING CONVECTIVE CELLS. HRRR AND LOCAL WRF MODELS IMPLY THAT
THIS DIURNAL CYCLE CONVECTION WILL FILL IN MORE AND PEAK DURING
EARLY EVENING...THEN DIMINISH SOMEWHAT...AND REGENERATE OVERNIGHT AS
THE TROUGH MOVES FARTHER TO THE EAST.
WILL MAINTAIN MID TO HIGH LIKELY POPS ACROSS MUCH OF THE FORECAST
AREA TONIGHT...WANING TO CHANCE POPS FOR THE NORTHERN NIAGARA
FRONTIER AND WESTERN TO CENTRAL LAKE ONTARIO. THE BULK OF PRECIP
WILL MOVE EAST THROUGH FRIDAY MORNING...WITH A CLEARING TREND TO
FOLLOW THROUGH THE AFTERNOON.
WE SHOULD HAVE ONE MORE MILD AND RATHER MUGGY NIGHT WITH LOWS IN THE
LOWER TO MID 60S ACROSS WESTERN NY...AND MID TO UPPER 60S FOR
CENTRAL AND NORTHERN NY. HIGHS ON FRIDAY WILL BE IN THE LOWER TO MID
70S ACROSS THE HILLS OF THE SOUTHERN TIER AND TUG HILL REGION...AND
THE MID TO UPPER 70S ELSEWHERE AIDED BY AFTERNOON SUNSHINE.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
A TRIO OF ENERGETIC SHORTWAVES WILL DROP INTO AND THROUGH AN ALREADY
ESTABLISHED HEMISPHERIC LONGWAVE TROUGH OVER EASTERN NORTH AMERICA
DURING THIS PERIOD...AND THIS WILL GUARANTEE THAT THE TROUGH WILL
REMAIN IN PLACE WHILE TEMPERATURES WILL AVERAGE BELOW NORMAL. WHILE
IT WILL BE SEASONABLY COOL...H85 TEMPS ARE NOT FORECAST TO DROP
BELOW 8C...SO ANOMALOUSLY CHILLY WEATHER IS NOT EXPECTED.
MEANWHILE AT THE SFC...EXPANSIVE HIGH PRESSURE WILL BUILD SOUTHEAST
FROM THE CANADIAN PRAIRIES ACROSS THE GREAT LAKES REGION TO THE OHIO
VALLEY. THIS WILL ENSURE MAINLY DRY WEATHER FOR THE PERIOD ALONG
WITH ABUNDANT SUNSHINE. THERE IS LITTLE ADDITIONAL DETAILED
INFORMATION TO ADD TO THIS OVERVIEW/FORECAST...BUT LETS TRY TO FILL
IN ANY REMAINING GAPS.
IN THE WAKE OF THE PASSING OF A PRIMARY COLD FRONT AND AN ENSUING
SHORTWAVE RIDGE DURING THE DAY FRIDAY...A SECONDARY COLD FRONT WILL
DROP ACROSS THE LOWER GREAT LAKES FRIDAY NIGHT. A DRY AIRMASS ABV 5K
FEET IS STILL BEING ADVERTISED BY THE GUIDANCE PACKAGES TO ACCOMPANY
THIS EVENT...SO WILL KEEP A DRY FORECAST INTACT WITH ONLY A BIT OF
LOW LEVEL CLOUD COVER.
ON SATURDAY...A LARGE CANADIAN HIGH WILL WORK ITS WAY ACROSS THE
UPPER GREAT LAKES...WHILE HELPING TO CIRCULATE COOLER AND NOTICEABLY
DRIER AIR ACROSS OUR FORECAST AREA. AFTERNOON HIGHS WILL BE IN THE
70S REGIONWIDE...BUT MORE IMPORTANTLY...DEW POINTS WILL BE SOME 10
DEG F LOWER THAN THE PREVIOUS DAY WITH READINGS IN THE LOWER 50S.
THIS SHOULD MAKE FOR A SALUBRIOUS DAY WITH AMPLE SUNSHINE TO GO
ALONG WITH THE COMFORTABLE CONDITIONS.
SATURDAY NIGHT WILL BE SOMEWHAT CHILLY AS THE SFC HIGH WILL DRIFT
CLOSE BY...RESULTING IN CLEAR SKIES AND LIGHT WINDS. OVERNIGHT LOWS
WILL RANGE FROM THE MID-UPPER 40S IN THE VALLEYS OF THE SRN TIER AND
EAST OF THE BLACK RIVER VALLEY...TO THE MID 50S ALONG THE LAKE
SHORES.
A SCINTILLATING DAY CAN THEN BE EXPECTED ON SUNDAY WITH THE CENTER
OF THE SFC HIGH DRIFTING BY TO OUR SOUTH. ONCE AGAIN...SUN FILLED
SKIES AND H85 TEMPS UNDER 10 C WILL RESULT IN A NICE DAY FOR OUTDOOR
ACTIVITIES.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
THE MEDIUM RANGE ENSEMBLES CONTINUE TO KEEP A DEEP LONGWAVE TROUGH
OVER THE EASTERN HALF OF NORTH AMERICA DURING THIS PERIOD. THIS WILL
FAVOR COOLER THAN AVERAGE TEMPERATURES...ALTHOUGH WE SHOULD
EXPERIENCE ONE DAY OF NEAR NORMAL READINGS AHEAD OF A REINFORCING
COLD FRONT. OUTSIDE OF RAIN FALL WITH THIS FRONTAL PASSAGE...DRY
WEATHER WILL PREVAIL.
A VIGOROUS SHORTWAVE DIVING SOUTH ACROSS WESTERN ONTARIO WILL PUSH A
COLD FRONT ACROSS THE UPPER GREAT LAKES ON MONDAY. SEASONABLY WARM
AIR WILL SURGE NORTHWARDS AHEAD OF THIS FRONT...AND THIS IN
COMBINATION WITH THE RETURN FLOW AROUND AN EXITING SFC HIGH WILL
HELP TO BOOST OUR TEMPERATURES TO NEAR 80F IN MANY AEREAS. WILL KEEP
RAIN FREE WEATHER IN PLACE FOR THE DAYLIGHT HOURS...BUT AS WE PUSH
THROUGH MONDAY NIGHT...THE FRONT IS EXPECTED TO MAKE ITS WAY ACROSS
MUCH OF OUR FORECAST AREA. THERE DOES NOT APPEAR TO BE MUCH MOISTURE
ASSOCIATED WITH THIS FRONT...SO WILL ONLY USE LOW CHC POPS AT THIS
POINT...INTRODUCING SUCH FOR MONDAY NIGHT AND EARLY TUESDAY.
AS THE ROBUST SHORTWAVE SWINGS THROUGH THE BASE OF THE TROUGH OVE
LAKE ONTARIO ON TUESDAY...THE NEXT EXPANSIVE SFC HIGH WILL SPRAWL
SOUTHWARDS ACROSS ALL OF THE GREAT LAKES REGION. THIS WILL OFFER
CLEARING SKIES FOR OUR REGION WITH ANY LEFTOVER SHOWER ACTIVITY
ENDING EARLY. H85 TEMPS ARE FORECAST DROP TO ABOUT 8C BY THE
AFTERNOON...SO IT WILL BE NOTICEABLY COOLER THAN MONDAY WITH
READINGS ONLY REACHING 70 TO 75 FOR MOST AREAS.
THE LARGE SFC HIGH WILL DRIFT ACROSS OUR FORECAST AREA WEDNESDAY AND
THURSDAY WHILE H85 TEMPS WILL REMAIN AT OR BELOW 10C. THIS WILL KEEP
FAIR DRY WEATHER IN PLACE WITH DAYTIME HIGHS GENERALLY IN THE LWOER
70S WHILE OVERNIGHT LOWS TUES AND WED NIGHTS WILL RANGE FROM THE MID
50S NEAR THE LAKES TO THE MID 40S IN THE COOLEST SRN TIER VALLEYS
AND EAST OF THE BLACK RIVER VALLEY.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
ALTHOUGH SHOWERS AND THUNDERSTORMS WILL BE LIKELY ACROSS MUCH OF THE
FORECAST AREA THIS EVENING THROUGH FRIDAY MORNING...THE MAJORITY OF
THE CONVECTION WILL BE TO THE SOUTH AND EAST OF MOST TAF SITES. THE
EXCEPTION WILL BE KJHW WHERE TSRA MAY DIRECTLY IMPACT THE SITE
THROUGH 22Z...THE EXPECT IFR CONDITIONS OVERNIGHT AFTER 08Z IN
LOCALLY DENSE FOG.
VFR CONDITIONS WILL PREVAIL ON FRIDAY AS THE WEAK SURFACE TROUGH
MOVES TO THE EAST OF THE AREA AND PARTIAL CLEARING OVERSPREADS.
OUTLOOK...
FRIDAY...MAINLY VFR WITH A CHANCE OF SHOWERS AND THUNDERSTORMS IN
CENTRAL NY WITH ASSOCIATED BRIEF MVFR/IFR.
SATURDAY AND SUNDAY...VFR.
MONDAY...VFR WITH CHANCE OF AFTERNOON SHOWERS AND THUNDERSTORMS.
TUESDAY...VFR.
&&
.MARINE...
THE PASSAGE OF A WEAK FRONTAL ZONE WILL SHIFT WINDS TO THE NORTHWEST
OR EVEN NORTH TONIGHT AND BRING WAVES UP TO AROUND 2 FEET ON THE
SOUTH SHORE OF BOTH LAKES. WINDS WILL DIMINISH AS HIGH PRESSURE
BUILDS IN THROUGH THE WEEKEND. AS IS TYPICAL OF MID SUMMER...WINDS
AND WAVES SHOULD REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA THROUGH
THE WEEKEND WITH A RELATIVELY WEAK PRESSURE GRADIENT IN PLACE.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...WCH
NEAR TERM...WCH
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...WCH
MARINE...HITCHCOCK/WCH
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
152 PM EDT THU AUG 8 2013
.SYNOPSIS...
A SLOW MOVING COLD FRONT WILL EVENTUALLY MOVE PAST THE REGION ON
FRIDAY NIGHT. IN THE MEANTIME...CHANCES FOR PERIODIC SHOWERS AND
A THUNDERSTORM OR TWO WILL CONTINUE FOR TODAY AND FRIDAY. A DRIER
WEEKEND IS IN STORE WITH TEMPERATURES REMAINING ON THE COOLER SIDE
OF NORMAL FOR AUGUST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1025 AM UPDATE...
AREA OF SHOWERS AND SOME THUNDER CONTINUES TO DIMINISH. WHILE MOST
OF THE AREA WILL REMAIN DRY THROUGH EARLY AFTERNOON...SHOWERS WILL
STILL BE POSSIBLE OVER THE NORTHERN TIER OF PA AND OTSEGO/DELAWARE
COUNTIES AS THESE CONTINUE TO DIMINISH. MEANWHILE AN AREA OF
CLEARING OVER THE FINGER LAKES AND CNY MAY BE ENOUGH WITH A COLD
FRONT OVER LAKE ERIE TO PROVIDE ANOTHER CHANCE THIS AFTERNOON.
BLENDED WITH THE PREVIOUS FORECAST OF HIGH CHANCE TO LOW LIKELY
LATER TODAY...BUT I DID TRY TO SHOW A NICE GAP OF MAINLY DRY
WEATHER BETWEEN NOW AND THEN. THE PREVIOUS AFD IS BELOW...
730 AM UPDATE... QUICK UPDATE TO ACCOUNT FOR LINE OF
STORMS MVG ACRS THE AREA EARLY THIS MRNG. HV TRIED TO TRACK
CATEGORICAL POPS THRU THE REGION THRU NOON TDA. TSTMS WL TAKE
AWHILE TO REACH THE I-81 CORRIDOR IN NEPA AND MAY FALL APART BFR
THEY DO AS THEY WL BE MVG INTO INCREASINGLY STABLE AIRMASS. MLCAPE
IS 500+ JOULES WHERE THEY ARE LOCATED NOW AND FURTHER TO THE EAST
IT DIMINISHES TO NR 250 J/KG PER SPC MESOANALYSIS PAGE. HWVR THINK
THAT A GOOD CHUNK OF THE AREA BTWN I-86/I-88 AND I-80 WILL SEE
SOME FORM OF PCPN THIS MORNING AND HV BUMPED POPS TO LKLY-
CATEGORICAL TO ACCNT FOR THIS. ONCE THIS LINE OF STORMS ROLLS THRU
THINK THAT MANY PLACES WL STABILIZE FOR THE REMAINDER OF THE DAY
WITH LITTLE ELSE EXPECTED. BUT THAT WL BE LOOKED AT IN FURTHER
DETAIL FOR THE NEXT UPDATE.
PREV DISCO BLO...
TODAY WILL BE A CRAZY...CONVOLUTED AND LOW CONFIDENCE FORECAST
GIVEN THE NATURE OF ZONAL FLOW PATTERNS IN THE SUMMER MONTHS. THE
FIRST ORDER OF BUSINESS WITH THIS MORNING`S UPDATE IS TO TRACK
AND TIME THE CONVECTION MOVING THROUGH WESTERN NEW YORK AND IT`S
IMPACT HERE IN CENTRAL DURING THE EARLY HOURS. CONVECTION LOOKS TO
BE MAINLY DRIVEN NOW BY COLD POOL INTERACTION WITHIN A BROAD
UNSTABLE ENVIRONMENT...AS WV LOOP SHOWS INITIATING SHORT WAVE IS
RUNNING OUT AHEAD OF THE CONVECTION ACROSS LOWER ONTARIO. LINEAR
TRACKING TAKES THE RAIN AND EMBEDDED TSRA ACROSS MAINLY THE FINGER
LAKES REGION AND NORTHERN PORTIONS OF THE SOUTHERN TIER DURING THE
EARLY DAYLIGHT HOURS AND HAVE ACCOUNTED FOR THIS WITH ABOUT 4-6
HOURS OF CATEGORICAL-LIKELY POPS OVER NORTHERN COUNTIES WITH SOME
SLACK ON THE SOUTHERN END OF THE POP FIELD FOR NEW DEVELOPMENT.
THINK THERE WILL ALSO CONTINUE TO BE WEAKENING OF THIS FEATURE AS
THE MORNING WEARS ON.
THEN...ATTENTION TURNS TO SLOWLY APPROACHING FRONTAL BOUNDARY FOR
LATER THIS AFTERNOON. AFTER SCOURING MANY MODEL SOLUTIONS...AND
PICKING THROUGH THE NOISE OF CONVECTIVE FEEDBACK...WE ARE HARD
PRESSED TO FIND MUCH IN THE WAY OF FORCING FOR NEW CONVECTION THIS
AFTERNOON ASIDE FROM MINOR HEIGHT AND PRESSURE FALLS ASSOCIATED
WITH THE FRONTAL BOUNDARY...FORMING IN TANDEM WITH DECREASING
DIURNAL STABILITY. THE MESOSCALE MODELS LIKE THE HRRR AND WRF-ARW
CONVECT MAINLY ALONG THE FRONTAL BOUNDARY MOVING INTO WRN NY THIS
AFTERNOON WITH SPOTTY ACTIVITY IN OUR AREA. WE THEREFORE FEEL MUCH
OF THE DAY WILL FEATURE...AT BEST... SCATTERED NEW CONVECTIVE
DEVELOPMENT ONCE THIS LINGERING RAIN FEATURE MAKES ITS WAY THROUGH
OR DISSIPATES IN THE PROCESS. HAVE THUS SCALED BACK ON ANY LIKELY
POPS WE HAD GOING THIS AFTERNOON.
OTHER PARAMETERS ARE FAIRLY ROUTINE. TEMPERATURES AS A BLEND OF
PREV FORECAST/00Z MOS AND 2M MODEL TEMPS AND LOOK TO BE MAINLY IN
THE UPPER 70S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
THE FORECAST GETS NO EASIER TONIGHT WITH FRONT ONLY SAGGING INTO
THE REGION. 00Z NAM AND GFS ARE SIMILAR IN FRONTAL PLACEMENT AND
UPPER AIR MASS FIELDS...BUT THE RESULTANT QPF FIELDS ARE VERY
DIFFERENT TONIGHT AND FRIDAY AND SEEM OVERDONE WITH RESPECT TO
VERY SUBTLE FORCING MECHANISMS. AGAIN...WEEDING THROUGH THE
CONVECTIVE FEEDBACK PROBLEMS AS BOTH MODELS TRY TO LIFT SOUTHERN
PLAINS CONVECTIVE VORTS THROUGH OUR REGION OVERNIGHT...WE ARE
AGAIN HARD PRESSED TO FIND SIGNIFICANT SYNOPTIC SUPPORT FOR AS
MUCH RAIN AS THESE MODELS ARE CRANKING OUT ON US. THAT SAID...THE
SFC FRONT WILL BE MOVING INTO THE REGION AND THERE IS A
POSSIBILITY THAT SOME MINOR UPPER LEVEL FEATURE COULD RUN FAST
THROUGH THE REGION. BOTH MODELS ALSO HINT AT AN INCRG SOUTHERLY
LOW LEVEL JET IMPINGING ON THE FRONTAL ZONE AND OUR HIGHER TERRAIN
AREAS IN NEPA/SENY LATE TONIGHT. WITHOUT MAKING TOO DRAMATIC A
SWING IN THE FORECAST...HAVE LOWERED SOME OF THE PREVIOUS FORECAST
POPS FOR TONIGHT AND FRIDAY...BUT HAVE MAINTAINED THE LIKELY
TERMINOLOGY AS THERE JUST DOESN`T SEEM TO BE MUCH THERE TO WARRANT
WIDESPREAD AREAS OF SHOWERS/TSRA. ALSO SHIFTED THE AXIS OF HIGHER
POPS A BIT WESTWARD TO LINE UP BETTER WITH THE FRONTAL MOVEMENT.
THE FOCUS ON THE SOUTHEAST ZONES JUST SEEMS UNREALISTIC AND THE
GFS SEEMED TO HAVE TRENDED A BIT WEST THIS RUN WITH NAM MORE IN
OUR EASTERN ZONES.
THE TRENDS THEN SUPPORT THE FRONT TO MOVE EAST OF THE REGION
FRIDAY NIGHT WITH DECREASING PRECIP PROBABILITY FROM WEST TO EAST
THROUGH THE DAY FRIDAY AND EVENTUALLY A DRY OVERNIGHT INTO SATURDAY.
HIGH PRESSURE AND COOL NORTHWESTERLY FLOW OVERSPREADS THE REGION
THIS WEEKEND. BEST CHANCE FOR SUNSHINE LOOKS TO BE SUNDAY AS COLD
ADVECTION CLOUDS ON THE FIRST DAY (SATURDAY) BEHIND A COLD FROPA
HERE SPELLS STRATOCU FIELDS GALORE AND PARTLY TO MOSTLY CLOUDY
CONDITIONS.
FOLLOWED MOS AND 2M MODEL BLENDED TEMPS ALONG WITH PREVIOUS
FORECAST WHICH HELPED TO COOL THINGS SLIGHTLY ON FRIDAY AND
SATURDAY FROM PREV FORECAST. THE TREND ON SATURDAY WILL CERTAINLY
FIT THE CLOUD IDEA.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
2 PM UPDATE...
MED RANGE MODELS IN FAIR AGREEMENT THRU THE LONG TERM. MODELS
ADVERTISING FROPA BEGINNING MON NGT AND THRU MOST OF THE AREA ON
TUESDAY, THUS HV POPS FOR THIS TIME PD. SHOWERS AND TSTMS EXPECTED
DRG THE AFTN HRS. 1020MB SFC HIGH WL BUILD IN AND LV DRY WX THRU
THE REST OF THE PD. TEMPS WL BE RUNNING BLO NORMAL THRU MID-WEEK.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
18Z UPDATE...
CIGS ARE MVFR/VFR AT THIS TIME AHEAD OF CDFNT THAT IS SAGGING
SOUTH TOWARD THE AREA. SHOWERS AND THUNDERSTORMS WILL DEVELOP
BETWEEN 20Z AND 24Z THUS HAVE TEMPO/D IN MVFR RESTRICTIONS. AFTER
THIS TIME ANY PRECIPITATION THAT DEVELOPS WILL BE AT RANDOM THUS
HAVE NOT INCLUDED IN TERMINAL FORECASTS AT THIS TIME. CIGS WILL
LOWER AFTER 06Z AT KSYR/KRME/KELM, AFTER 04Z AT HIGHER ELEVATION
TERMINALS OF KITH/KBGM. WITH MARINE LAYER EXPECTED TO MOVE BACK IN
KAVP WILL BE THE FIRST SITE TO SEE MVFR RESTRICTIONS AT 02Z.
POTENTIAL FOR IFR WILL EXIST AT KITH AND KBGM BETWEEN 08Z AND 12Z.
FRONTAL PASSAGE EXPECTED TO OCCUR AT NY TERMINALS AROUND 15Z WITH
MVFR CIGS HANGING AROUND THROUGH 18Z FRIDAY.
WINDS OUT OF THE SOUTH AROUND 5KTS WILL BECOME LIGHT OVERNIGHT
THEN SWITCH AROUND TO NORTHWEST AFTER 15Z FRIDAY.
OUTLOOK...
FRI...VFR BUT MVFR IN SCATTERED SHRA/TSRA MAINLY SOUTH.
SAT THRU MON...VFR.
MON NGT/TUE...MVFR RESTRICTION IN SHRA/TSRA.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JAB
NEAR TERM...HEDEN/JAB/PVN
SHORT TERM...JAB
LONG TERM...PVN
AVIATION...PVN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1025 AM EDT THU AUG 8 2013
.SYNOPSIS...
A SLOW MOVING COLD FRONT WILL EVENTUALLY MOVE PAST THE REGION ON
FRIDAY NIGHT. IN THE MEANTIME...CHANCES FOR PERIODIC SHOWERS AND
A THUNDERSTORM OR TWO WILL CONTINUE FOR TODAY AND FRIDAY. A DRIER
WEEKEND IS IN STORE WITH TEMPERATURES REMAINING ON THE COOLER SIDE
OF NORMAL FOR AUGUST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1025 AM UPDATE...
AREA OF SHOWERS AND SOME THUNDER CONTINUES TO DIMINISH. WHILE MOST
OF THE AREA WILL REMAIN DRY THROUGH EARLY AFTERNOON...SHOWERS WILL
STILL BE POSSIBLE OVER THE NORTHERN TIER OF PA AND OTSEGO/DELAWARE
COUNTIES AS THESE CONTINUE TO DIMINISH. MEANWHILE AN AREA OF
CLEARING OVER THE FINGER LAKES AND CNY MAY BE ENOUGH WITH A COLD
FRONT OVER LAKE ERIE TO PROVIDE ANOTHER CHANCE THIS AFTERNOON.
BLENDED WITH THE PREVIOUS FORECAST OF HIGH CHANCE TO LOW LIKELY
LATER TODAY...BUT I DID TRY TO SHOW A NICE GAP OF MAINLY DRY
WEATHER BETWEEN NOW AND THEN. THE PREVIOUS AFD IS BELOW...
730 AM UPDATE... QUICK UPDATE TO ACCOUNT FOR LINE OF
STORMS MVG ACRS THE AREA EARLY THIS MRNG. HV TRIED TO TRACK
CATEGORICAL POPS THRU THE REGION THRU NOON TDA. TSTMS WL TAKE
AWHILE TO REACH THE I-81 CORRIDOR IN NEPA AND MAY FALL APART BFR
THEY DO AS THEY WL BE MVG INTO INCREASINGLY STABLE AIRMASS. MLCAPE
IS 500+ JOULES WHERE THEY ARE LOCATED NOW AND FURTHER TO THE EAST
IT DIMINISHES TO NR 250 J/KG PER SPC MESOANALYSIS PAGE. HWVR THINK
THAT A GOOD CHUNK OF THE AREA BTWN I-86/I-88 AND I-80 WILL SEE
SOME FORM OF PCPN THIS MORNING AND HV BUMPED POPS TO LKLY-
CATEGORICAL TO ACCNT FOR THIS. ONCE THIS LINE OF STORMS ROLLS THRU
THINK THAT MANY PLACES WL STABILIZE FOR THE REMAINDER OF THE DAY
WITH LITTLE ELSE EXPECTED. BUT THAT WL BE LOOKED AT IN FURTHER
DETAIL FOR THE NEXT UPDATE.
PREV DISCO BLO...
TODAY WILL BE A CRAZY...CONVOLUTED AND LOW CONFIDENCE FORECAST
GIVEN THE NATURE OF ZONAL FLOW PATTERNS IN THE SUMMER MONTHS. THE
FIRST ORDER OF BUSINESS WITH THIS MORNING`S UPDATE IS TO TRACK
AND TIME THE CONVECTION MOVING THROUGH WESTERN NEW YORK AND IT`S
IMPACT HERE IN CENTRAL DURING THE EARLY HOURS. CONVECTION LOOKS TO
BE MAINLY DRIVEN NOW BY COLD POOL INTERACTION WITHIN A BROAD
UNSTABLE ENVIRONMENT...AS WV LOOP SHOWS INITIATING SHORT WAVE IS
RUNNING OUT AHEAD OF THE CONVECTION ACROSS LOWER ONTARIO. LINEAR
TRACKING TAKES THE RAIN AND EMBEDDED TSRA ACROSS MAINLY THE FINGER
LAKES REGION AND NORTHERN PORTIONS OF THE SOUTHERN TIER DURING THE
EARLY DAYLIGHT HOURS AND HAVE ACCOUNTED FOR THIS WITH ABOUT 4-6
HOURS OF CATEGORICAL-LIKELY POPS OVER NORTHERN COUNTIES WITH SOME
SLACK ON THE SOUTHERN END OF THE POP FIELD FOR NEW DEVELOPMENT.
THINK THERE WILL ALSO CONTINUE TO BE WEAKENING OF THIS FEATURE AS
THE MORNING WEARS ON.
THEN...ATTENTION TURNS TO SLOWLY APPROACHING FRONTAL BOUNDARY FOR
LATER THIS AFTERNOON. AFTER SCOURING MANY MODEL SOLUTIONS...AND
PICKING THROUGH THE NOISE OF CONVECTIVE FEEDBACK...WE ARE HARD
PRESSED TO FIND MUCH IN THE WAY OF FORCING FOR NEW CONVECTION THIS
AFTERNOON ASIDE FROM MINOR HEIGHT AND PRESSURE FALLS ASSOCIATED
WITH THE FRONTAL BOUNDARY...FORMING IN TANDEM WITH DECREASING
DIURNAL STABILITY. THE MESOSCALE MODELS LIKE THE HRRR AND WRF-ARW
CONVECT MAINLY ALONG THE FRONTAL BOUNDARY MOVING INTO WRN NY THIS
AFTERNOON WITH SPOTTY ACTIVITY IN OUR AREA. WE THEREFORE FEEL MUCH
OF THE DAY WILL FEATURE...AT BEST... SCATTERED NEW CONVECTIVE
DEVELOPMENT ONCE THIS LINGERING RAIN FEATURE MAKES ITS WAY THROUGH
OR DISSIPATES IN THE PROCESS. HAVE THUS SCALED BACK ON ANY LIKELY
POPS WE HAD GOING THIS AFTERNOON.
OTHER PARAMETERS ARE FAIRLY ROUTINE. TEMPERATURES AS A BLEND OF
PREV FORECAST/00Z MOS AND 2M MODEL TEMPS AND LOOK TO BE MAINLY IN
THE UPPER 70S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
THE FORECAST GETS NO EASIER TONIGHT WITH FRONT ONLY SAGGING INTO
THE REGION. 00Z NAM AND GFS ARE SIMILAR IN FRONTAL PLACEMENT AND
UPPER AIR MASS FIELDS...BUT THE RESULTANT QPF FIELDS ARE VERY
DIFFERENT TONIGHT AND FRIDAY AND SEEM OVERDONE WITH RESPECT TO
VERY SUBTLE FORCING MECHANISMS. AGAIN...WEEDING THROUGH THE
CONVECTIVE FEEDBACK PROBLEMS AS BOTH MODELS TRY TO LIFT SOUTHERN
PLAINS CONVECTIVE VORTS THROUGH OUR REGION OVERNIGHT...WE ARE
AGAIN HARD PRESSED TO FIND SIGNIFICANT SYNOPTIC SUPPORT FOR AS
MUCH RAIN AS THESE MODELS ARE CRANKING OUT ON US. THAT SAID...THE
SFC FRONT WILL BE MOVING INTO THE REGION AND THERE IS A
POSSIBILITY THAT SOME MINOR UPPER LEVEL FEATURE COULD RUN FAST
THROUGH THE REGION. BOTH MODELS ALSO HINT AT AN INCRG SOUTHERLY
LOW LEVEL JET IMPINGING ON THE FRONTAL ZONE AND OUR HIGHER TERRAIN
AREAS IN NEPA/SENY LATE TONIGHT. WITHOUT MAKING TOO DRAMATIC A
SWING IN THE FORECAST...HAVE LOWERED SOME OF THE PREVIOUS FORECAST
POPS FOR TONIGHT AND FRIDAY...BUT HAVE MAINTAINED THE LIKELY
TERMINOLOGY AS THERE JUST DOESN`T SEEM TO BE MUCH THERE TO WARRANT
WIDESPREAD AREAS OF SHOWERS/TSRA. ALSO SHIFTED THE AXIS OF HIGHER
POPS A BIT WESTWARD TO LINE UP BETTER WITH THE FRONTAL MOVEMENT.
THE FOCUS ON THE SOUTHEAST ZONES JUST SEEMS UNREALISTIC AND THE
GFS SEEMED TO HAVE TRENDED A BIT WEST THIS RUN WITH NAM MORE IN
OUR EASTERN ZONES.
THE TRENDS THEN SUPPORT THE FRONT TO MOVE EAST OF THE REGION
FRIDAY NIGHT WITH DECREASING PRECIP PROBABILITY FROM WEST TO EAST
THROUGH THE DAY FRIDAY AND EVENTUALLY A DRY OVERNIGHT INTO SATURDAY.
HIGH PRESSURE AND COOL NORTHWESTERLY FLOW OVERSPREADS THE REGION
THIS WEEKEND. BEST CHANCE FOR SUNSHINE LOOKS TO BE SUNDAY AS COLD
ADVECTION CLOUDS ON THE FIRST DAY (SATURDAY) BEHIND A COLD FROPA
HERE SPELLS STRATOCU FIELDS GALORE AND PARTLY TO MOSTLY CLOUDY
CONDITIONS.
FOLLOWED MOS AND 2M MODEL BLENDED TEMPS ALONG WITH PREVIOUS
FORECAST WHICH HELPED TO COOL THINGS SLIGHTLY ON FRIDAY AND
SATURDAY FROM PREV FORECAST. THE TREND ON SATURDAY WILL CERTAINLY
FIT THE CLOUD IDEA.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
4 AM UPDATE...
VERY FEW CHANGES MADE TO INHERITED GRIDS AS GOOD AGREEMENT BETWEEN
THE GFS AND ECMWF SUPPORTS BETTER THAN AVERAGE CONFIDENCE THROUGH
THE PERIOD. UPPER PATTERN THROUGH THE TIME FRAME WILL BE DOMINATED
BY BROAD CYCLONIC FLOW ALOFT AS A BLOCKY MID-LATITUDE PATTERN
PERSISTS THANKS TO STRONG HIGH PRESSURE ACROSS THE NORTHERN ATLANTIC
AND CANADIAN PRAIRIE PROVINCES. BOTH THE GFS AND ECMWF AGREE THAT A
SECOND UPPER LOW WILL SWING SOUTH FROM HUDSON BAY BY LATE MON/EARLY
TUESDAY WHICH WILL SEND A COLD FRONT EAST ACROSS OUR REGION AS LOW
PRESSURE TRACKS JUST OFF TO OUR NORTH. THUS EXPECT RENEWED SHWR AND
THUNDERSTORM CHANCES BY TUESDAY BEFORE DRY WX RETURNS TO CONCLUDE
THE PERIOD. BELOW NORMAL TEMPS EXPECTED WITH NO HINTS OF ANY MAJOR
WARMING SEEN FOR THE FORESEEABLE FUTURE.
200 PM UPDATE...
AREA REMAINS UNDER A BROAD LONG WAVE UPPER LEVEL TROUGH THROUGH
THE PERIOD AND SLIGHTLY COOLER THAN NORMAL TEMPERATURES WITH HIGHS
IN LOWER TO MIDDLE 70S AND NIGHTTIME LOWS IN THE 50S.
A FRONT THAT MOVED THROUGH THE AREA EARLY SATURDAY IS FORECAST TO
STALL IN A EAST-WEST MANNER ACROSS VIRGINA SATURDAY NIGHT INTO
SUNDAY. FROM THIS POINT MODELS HAVE DIFFERENCES OF TIMING AND
POSITIONING OF WAVES MOVING EASTWARD ALONG THIS FRONT THROUGH
MIDWEEK CAUSING SOME UNCERTAINTY IN THE FORECAST.
FORECASTED CLOUDS TO SPREAD NORTH WITH A WAVE ON SUNDAY BUT JUST
PLACED A SLIGHT CHANCE THUNDERSTORMS IN THE POCONOS FOR SUNDAY
AFTERNOON. HIGH PRESSURE BUILDS ACROSS SUNDAY NIGHT BEHIND THIS
WAVE. A SHORT-WAVE MOVING AROUND THE UPR LEVEL LOW TO OUR NORTH
MAY BRING A SLIGHT CHANCE OF SHOWERS OR THUNDERSTORMS IN THE
AFTERNOON MONDAY.
UNCERTAINTY INCREASES TUESDAY AS GFS LINKS A SHORT-WAVE MOVING
AROUND THE UPR LOW TO THE NORTH WITH A SURFACE LOW AND WAVE MOVING
NORTHEAST ALONG THAT FRONTAL ZONE AND SPREADS CLOUDS AND
PRECIPITATION NORTHEAST ACROSS THE AREA TUESDAY. ON THE OTHER HAND
THE ECMWF DOES NOT LINK A WAVE UP FROM THE SOUTH WITH JUST AN
ISOLATED CHANCE. PUT A 30 POP IN TUESDAY AFTERNOON. SURFACE HIGH
PRESSURE BUILDS IN FOR WEDNESDAY WITH A SHORTWAVE RIDGE ALOFT.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
AN AREA OF SHWRS AND EMBEDDED THUNDER WILL CONTINUE MOVING EAST
THROUGH THE REGION THIS MORNING. BASED ON LATEST RADAR
TRENDS...MOST CONCENTRATED ACTIVITY WILL PREVAIL FROM THE CENTRAL
FINGER LAKES SOUTH THROUGH THE TWIN TIERS WHERE TEMPORARY MVFR AND
POTENTIALLY SOME SHORT DURATION IFR WILL BE POSSIBLE. ELSEWHERE
AT SYR AND RME...CURRENT ACTIVITY WILL LIKELY POSE LITTLE IF ANY
RESTRICTIONS AS HEAVIEST RAINS REMAIN SOUTH. A LITTLE MORE
UNCERTAIN DOWN AT AVP AS A FAIR AMOUNT OF LAND STILL NEEDS TO BE
COVERED BEFORE REACHING THE TERMINAL. FOR NOW...HAVE INSERTED A
TEMPO GROUP STARTING AT 14Z FOR POSSIBLE MVFR RESTRICTIONS.
AFTER THIS PASSES...FCST BECOMES MUCH MORE CONVOLUTED AS MODELS
CONTINUE TO SHOW SEVERAL CLUSTERS OF SHWRS/STORMS DEVELOPING AFTER
THE 18Z TIME FRAME. FOR NOW...HAVE DECIDED TO OFFER A TEMPO TSRA
MENTION EVERYWHERE BETWEEN 18-21Z UNDER THE PREMISE THAT DAYSHIFT
CAN UPDATE ONCE TRENDS BEHIND THIS MORNING/S DEPARTING WAVE BECOME
A LITTLE MORE CERTAIN. BY TONIGHT...MAIN ACTIVITY TO LIKELY
IMPACT AVP AS ADDITIONAL MOISTURE BEGINS WORKING NORTH ALONG A
COLD FRONT. ELSEWHERE...WIDESPREAD MVFR RESTRICTIONS EXPECTED TO
DEVELOP WITH OCCASIONAL IFR POSSIBLE AT BGM AND ITH AS MOISTURE
BECOMES TRAPPED BELOW DEVELOPING FRONTAL INVERSION.
OUTLOOK...
FRI...VFR BUT MVFR IN SCATTERED SHRA/TSRA MAINLY SOUTH.
SAT THRU MON...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JAB
NEAR TERM...HEDEN/JAB/PVN
SHORT TERM...JAB
LONG TERM...BMW/CMG
AVIATION...CMG
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
747 AM EDT THU AUG 8 2013
.SYNOPSIS...
A SLOW MOVING COLD FRONT WILL EVENTUALLY MOVE PAST THE REGION ON
FRIDAY NIGHT. IN THE MEANTIME...CHANCES FOR PERIODIC SHOWERS AND
A THUNDERSTORM OR TWO WILL CONTINUE FOR TODAY AND FRIDAY. A DRIER
WEEKEND IS IN STORE WITH TEMPERATURES REMAINING ON THE COOLER SIDE
OF NORMAL FOR AUGUST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
730 AM UPDATE...
QUICK UPDATE TO ACCOUNT FOR LINE OF STORMS MVG ACRS THE AREA EARLY
THIS MRNG. HV TRIED TO TRACK CATEGORICAL POPS THRU THE REGION THRU
NOON TDA. TSTMS WL TAKE AWHILE TO REACH THE I-81 CORRIDOR IN NEPA
AND MAY FALL APART BFR THEY DO AS THEY WL BE MVG INTO INCREASINGLY
STABLE AIRMASS. MLCAPE IS 500+ JOULES WHERE THEY ARE LOCATED NOW
AND FURTHER TO THE EAST IT DIMINISHES TO NR 250 J/KG PER SPC
MESOANALYSIS PAGE. HWVR THINK THAT A GOOD CHUNK OF THE AREA BTWN
I-86/I-88 AND I-80 WILL SEE SOME FORM OF PCPN THIS MORNING AND HV BUMPED
POPS TO LKLY-CATEGORICAL TO ACCNT FOR THIS. ONCE THIS LINE OF
STORMS ROLLS THRU THINK THAT MANY PLACES WL STABILIZE FOR THE
REMAINDER OF THE DAY WITH LITTLE ELSE EXPECTED. BUT THAT WL BE
LOOKED AT IN FURTHER DETAIL FOR THE NEXT UPDATE.
PREV DISCO BLO...
TODAY WILL BE A CRAZY...CONVOLUTED AND LOW CONFIDENCE FORECAST
GIVEN THE NATURE OF ZONAL FLOW PATTERNS IN THE SUMMER MONTHS. THE
FIRST ORDER OF BUSINESS WITH THIS MORNING`S UPDATE IS TO TRACK
AND TIME THE CONVECTION MOVING THROUGH WESTERN NEW YORK AND IT`S
IMPACT HERE IN CENTRAL DURING THE EARLY HOURS. CONVECTION LOOKS TO
BE MAINLY DRIVEN NOW BY COLD POOL INTERACTION WITHIN A BROAD
UNSTABLE ENVIRONMENT...AS WV LOOP SHOWS INITIATING SHORT WAVE IS
RUNNING OUT AHEAD OF THE CONVECTION ACROSS LOWER ONTARIO. LINEAR
TRACKING TAKES THE RAIN AND EMBEDDED TSRA ACROSS MAINLY THE FINGER
LAKES REGION AND NORTHERN PORTIONS OF THE SOUTHERN TIER DURING THE
EARLY DAYLIGHT HOURS AND HAVE ACCOUNTED FOR THIS WITH ABOUT 4-6
HOURS OF CATEGORICAL-LIKELY POPS OVER NORTHERN COUNTIES WITH SOME
SLACK ON THE SOUTHERN END OF THE POP FIELD FOR NEW DEVELOPMENT.
THINK THERE WILL ALSO CONTINUE TO BE WEAKENING OF THIS FEATURE AS
THE MORNING WEARS ON.
THEN...ATTENTION TURNS TO SLOWLY APPROACHING FRONTAL BOUNDARY FOR
LATER THIS AFTERNOON. AFTER SCOURING MANY MODEL SOLUTIONS...AND
PICKING THROUGH THE NOISE OF CONVECTIVE FEEDBACK...WE ARE HARD
PRESSED TO FIND MUCH IN THE WAY OF FORCING FOR NEW CONVECTION THIS
AFTERNOON ASIDE FROM MINOR HEIGHT AND PRESSURE FALLS ASSOCIATED
WITH THE FRONTAL BOUNDARY...FORMING IN TANDEM WITH DECREASING
DIURNAL STABILITY. THE MESOSCALE MODELS LIKE THE HRRR AND WRF-ARW
CONVECT MAINLY ALONG THE FRONTAL BOUNDARY MOVING INTO WRN NY THIS
AFTERNOON WITH SPOTTY ACTIVITY IN OUR AREA. WE THEREFORE FEEL MUCH
OF THE DAY WILL FEATURE...AT BEST... SCATTERED NEW CONVECTIVE
DEVELOPMENT ONCE THIS LINGERING RAIN FEATURE MAKES ITS WAY THROUGH
OR DISSIPATES IN THE PROCESS. HAVE THUS SCALED BACK ON ANY LIKELY
POPS WE HAD GOING THIS AFTERNOON.
OTHER PARAMETERS ARE FAIRLY ROUTINE. TEMPERATURES AS A BLEND OF
PREV FORECAST/00Z MOS AND 2M MODEL TEMPS AND LOOK TO BE MAINLY IN
THE UPPER 70S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
THE FORECAST GETS NO EASIER TONIGHT WITH FRONT ONLY SAGGING INTO
THE REGION. 00Z NAM AND GFS ARE SIMILAR IN FRONTAL PLACEMENT AND
UPPER AIR MASS FIELDS...BUT THE RESULTANT QPF FIELDS ARE VERY
DIFFERENT TONIGHT AND FRIDAY AND SEEM OVERDONE WITH RESPECT TO
VERY SUBTLE FORCING MECHANISMS. AGAIN...WEEDING THROUGH THE
CONVECTIVE FEEDBACK PROBLEMS AS BOTH MODELS TRY TO LIFT SOUTHERN
PLAINS CONVECTIVE VORTS THROUGH OUR REGION OVERNIGHT...WE ARE
AGAIN HARD PRESSED TO FIND SIGNIFICANT SYNOPTIC SUPPORT FOR AS
MUCH RAIN AS THESE MODELS ARE CRANKING OUT ON US. THAT SAID...THE
SFC FRONT WILL BE MOVING INTO THE REGION AND THERE IS A
POSSIBILITY THAT SOME MINOR UPPER LEVEL FEATURE COULD RUN FAST
THROUGH THE REGION. BOTH MODELS ALSO HINT AT AN INCRG SOUTHERLY
LOW LEVEL JET IMPINGING ON THE FRONTAL ZONE AND OUR HIGHER TERRAIN
AREAS IN NEPA/SENY LATE TONIGHT. WITHOUT MAKING TOO DRAMATIC A
SWING IN THE FORECAST...HAVE LOWERED SOME OF THE PREVIOUS FORECAST
POPS FOR TONIGHT AND FRIDAY...BUT HAVE MAINTAINED THE LIKELY
TERMINOLOGY AS THERE JUST DOESN`T SEEM TO BE MUCH THERE TO WARRANT
WIDESPREAD AREAS OF SHOWERS/TSRA. ALSO SHIFTED THE AXIS OF HIGHER
POPS A BIT WESTWARD TO LINE UP BETTER WITH THE FRONTAL MOVEMENT.
THE FOCUS ON THE SOUTHEAST ZONES JUST SEEMS UNREALISTIC AND THE
GFS SEEMED TO HAVE TRENDED A BIT WEST THIS RUN WITH NAM MORE IN
OUR EASTERN ZONES.
THE TRENDS THEN SUPPORT THE FRONT TO MOVE EAST OF THE REGION
FRIDAY NIGHT WITH DECREASING PRECIP PROBABILITY FROM WEST TO EAST
THROUGH THE DAY FRIDAY AND EVENTUALLY A DRY OVERNIGHT INTO SATURDAY.
HIGH PRESSURE AND COOL NORTHWESTERLY FLOW OVERSPREADS THE REGION
THIS WEEKEND. BEST CHANCE FOR SUNSHINE LOOKS TO BE SUNDAY AS COLD
ADVECTION CLOUDS ON THE FIRST DAY (SATURDAY) BEHIND A COLD FROPA
HERE SPELLS STRATOCU FIELDS GALORE AND PARTLY TO MOSTLY CLOUDY
CONDITIONS.
FOLLOWED MOS AND 2M MODEL BLENDED TEMPS ALONG WITH PREVIOUS
FORECAST WHICH HELPED TO COOL THINGS SLIGHTLY ON FRIDAY AND
SATURDAY FROM PREV FORECAST. THE TREND ON SATURDAY WILL CERTAINLY
FIT THE CLOUD IDEA.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
4 AM UPDATE...
VERY FEW CHANGES MADE TO INHERITED GRIDS AS GOOD AGREEMENT BETWEEN
THE GFS AND ECMWF SUPPORTS BETTER THAN AVERAGE CONFIDENCE THROUGH
THE PERIOD. UPPER PATTERN THROUGH THE TIME FRAME WILL BE DOMINATED
BY BROAD CYCLONIC FLOW ALOFT AS A BLOCKY MID-LATITUDE PATTERN
PERSISTS THANKS TO STRONG HIGH PRESSURE ACROSS THE NORTHERN ATLANTIC
AND CANADIAN PRAIRIE PROVINCES. BOTH THE GFS AND ECMWF AGREE THAT A
SECOND UPPER LOW WILL SWING SOUTH FROM HUDSON BAY BY LATE MON/EARLY
TUESDAY WHICH WILL SEND A COLD FRONT EAST ACROSS OUR REGION AS LOW
PRESSURE TRACKS JUST OFF TO OUR NORTH. THUS EXPECT RENEWED SHWR AND
THUNDERSTORM CHANCES BY TUESDAY BEFORE DRY WX RETURNS TO CONCLUDE
THE PERIOD. BELOW NORMAL TEMPS EXPECTED WITH NO HINTS OF ANY MAJOR
WARMING SEEN FOR THE FORESEEABLE FUTURE.
200 PM UPDATE...
AREA REMAINS UNDER A BROAD LONG WAVE UPPER LEVEL TROUGH THROUGH
THE PERIOD AND SLIGHTLY COOLER THAN NORMAL TEMPERATURES WITH HIGHS
IN LOWER TO MIDDLE 70S AND NIGHTTIME LOWS IN THE 50S.
A FRONT THAT MOVED THROUGH THE AREA EARLY SATURDAY IS FORECAST TO
STALL IN A EAST-WEST MANNER ACROSS VIRGINA SATURDAY NIGHT INTO
SUNDAY. FROM THIS POINT MODELS HAVE DIFFERENCES OF TIMING AND
POSITIONING OF WAVES MOVING EASTWARD ALONG THIS FRONT THROUGH
MIDWEEK CAUSING SOME UNCERTAINTY IN THE FORECAST.
FORECASTED CLOUDS TO SPREAD NORTH WITH A WAVE ON SUNDAY BUT JUST
PLACED A SLIGHT CHANCE THUNDERSTORMS IN THE POCONOS FOR SUNDAY
AFTERNOON. HIGH PRESSURE BUILDS ACROSS SUNDAY NIGHT BEHIND THIS
WAVE. A SHORT-WAVE MOVING AROUND THE UPR LEVEL LOW TO OUR NORTH
MAY BRING A SLIGHT CHANCE OF SHOWERS OR THUNDERSTORMS IN THE
AFTERNOON MONDAY.
UNCERTAINTY INCREASES TUESDAY AS GFS LINKS A SHORT-WAVE MOVING
AROUND THE UPR LOW TO THE NORTH WITH A SURFACE LOW AND WAVE MOVING
NORTHEAST ALONG THAT FRONTAL ZONE AND SPREADS CLOUDS AND
PRECIPITATION NORTHEAST ACROSS THE AREA TUESDAY. ON THE OTHER HAND
THE ECMWF DOES NOT LINK A WAVE UP FROM THE SOUTH WITH JUST AN
ISOLATED CHANCE. PUT A 30 POP IN TUESDAY AFTERNOON. SURFACE HIGH
PRESSURE BUILDS IN FOR WEDNESDAY WITH A SHORTWAVE RIDGE ALOFT.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AN AREA OF SHWRS AND EMBEDDED THUNDER WILL CONTINUE MOVING EAST
THROUGH THE REGION THIS MORNING. BASED ON LATEST RADAR
TRENDS...MOST CONCENTRATED ACTIVITY WILL PREVAIL FROM THE CENTRAL
FINGER LAKES SOUTH THROUGH THE TWIN TIERS WHERE TEMPORARY MVFR AND
POTENTIALLY SOME SHORT DURATION IFR WILL BE POSSIBLE. ELSEWHERE
AT SYR AND RME...CURRENT ACTIVITY WILL LIKELY POSE LITTLE IF ANY
RESTRICTIONS AS HEAVIEST RAINS REMAIN SOUTH. A LITTLE MORE
UNCERTAIN DOWN AT AVP AS A FAIR AMOUNT OF LAND STILL NEEDS TO BE
COVERED BEFORE REACHING THE TERMINAL. FOR NOW...HAVE INSERTED A
TEMPO GROUP STARTING AT 14Z FOR POSSIBLE MVFR RESTRICTIONS.
AFTER THIS PASSES...FCST BECOMES MUCH MORE CONVOLUTED AS MODELS
CONTINUE TO SHOW SEVERAL CLUSTERS OF SHWRS/STORMS DEVELOPING AFTER
THE 18Z TIME FRAME. FOR NOW...HAVE DECIDED TO OFFER A TEMPO TSRA
MENTION EVERYWHERE BETWEEN 18-21Z UNDER THE PREMISE THAT DAYSHIFT
CAN UPDATE ONCE TRENDS BEHIND THIS MORNING/S DEPARTING WAVE BECOME
A LITTLE MORE CERTAIN. BY TONIGHT...MAIN ACTIVITY TO LIKELY
IMPACT AVP AS ADDITIONAL MOISTURE BEGINS WORKING NORTH ALONG A
COLD FRONT. ELSEWHERE...WIDESPREAD MVFR RESTRICTIONS EXPECTED TO
DEVELOP WITH OCCASIONAL IFR POSSIBLE AT BGM AND ITH AS MOISTURE
BECOMES TRAPPED BELOW DEVELOPING FRONTAL INVERSION.
OUTLOOK...
FRI...VFR BUT MVFR IN SCATTERED SHRA/TSRA MAINLY SOUTH.
SAT THRU MON...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JAB
NEAR TERM...JAB/PVN
SHORT TERM...JAB
LONG TERM...BMW/CMG
AVIATION...CMG
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
652 AM EDT THU AUG 8 2013
.SYNOPSIS...
A SLOW MOVING COLD FRONT WILL EVENTUALLY MOVE PAST THE REGION ON
FRIDAY NIGHT. IN THE MEANTIME...CHANCES FOR PERIODIC SHOWERS AND
A THUNDERSTORM OR TWO WILL CONTINUE FOR TODAY AND FRIDAY. A DRIER
WEEKEND IS IN STORE WITH TEMPERATURES REMAINING ON THE COOLER SIDE
OF NORMAL FOR AUGUST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
TODAY WILL BE A CRAZY...CONVOLUTED AND LOW CONFIDENCE FORECAST
GIVEN THE NATURE OF ZONAL FLOW PATTERNS IN THE SUMMER MONTHS. THE
FIRST ORDER OF BUSINESS WITH THIS MORNING`S UPDATE IS TO TRACK
AND TIME THE CONVECTION MOVING THROUGH WESTERN NEW YORK AND IT`S
IMPACT HERE IN CENTRAL DURING THE EARLY HOURS. CONVECTION LOOKS TO
BE MAINLY DRIVEN NOW BY COLD POOL INTERACTION WITHIN A BROAD
UNSTABLE ENVIRONMENT...AS WV LOOP SHOWS INITIATING SHORT WAVE IS
RUNNING OUT AHEAD OF THE CONVECTION ACROSS LOWER ONTARIO. LINEAR
TRACKING TAKES THE RAIN AND EMBEDDED TSRA ACROSS MAINLY THE FINGER
LAKES REGION AND NORTHERN PORTIONS OF THE SOUTHERN TIER DURING THE
EARLY DAYLIGHT HOURS AND HAVE ACCOUNTED FOR THIS WITH ABOUT 4-6
HOURS OF CATEGORICAL-LIKELY POPS OVER NORTHERN COUNTIES WITH SOME
SLACK ON THE SOUTHERN END OF THE POP FIELD FOR NEW DEVELOPMENT.
THINK THERE WILL ALSO CONTINUE TO BE WEAKENING OF THIS FEATURE AS
THE MORNING WEARS ON.
THEN...ATTENTION TURNS TO SLOWLY APPROACHING FRONTAL BOUNDARY FOR
LATER THIS AFTERNOON. AFTER SCOURING MANY MODEL SOLUTIONS...AND
PICKING THROUGH THE NOISE OF CONVECTIVE FEEDBACK...WE ARE HARD
PRESSED TO FIND MUCH IN THE WAY OF FORCING FOR NEW CONVECTION THIS
AFTERNOON ASIDE FROM MINOR HEIGHT AND PRESSURE FALLS ASSOCIATED
WITH THE FRONTAL BOUNDARY...FORMING IN TANDEM WITH DECREASING
DIURNAL STABILITY. THE MESOSCALE MODELS LIKE THE HRRR AND WRF-ARW
CONVECT MAINLY ALONG THE FRONTAL BOUNDARY MOVING INTO WRN NY THIS
AFTERNOON WITH SPOTTY ACTIVITY IN OUR AREA. WE THEREFORE FEEL MUCH
OF THE DAY WILL FEATURE...AT BEST... SCATTERED NEW CONVECTIVE
DEVELOPMENT ONCE THIS LINGERING RAIN FEATURE MAKES ITS WAY THROUGH
OR DISSIPATES IN THE PROCESS. HAVE THUS SCALED BACK ON ANY LIKELY
POPS WE HAD GOING THIS AFTERNOON.
OTHER PARAMETERS ARE FAIRLY ROUTINE. TEMPERATURES AS A BLEND OF
PREV FORECAST/00Z MOS AND 2M MODEL TEMPS AND LOOK TO BE MAINLY IN
THE UPPER 70S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
THE FORECAST GETS NO EASIER TONIGHT WITH FRONT ONLY SAGGING INTO
THE REGION. 00Z NAM AND GFS ARE SIMILAR IN FRONTAL PLACEMENT AND
UPPER AIR MASS FIELDS...BUT THE RESULTANT QPF FIELDS ARE VERY
DIFFERENT TONIGHT AND FRIDAY AND SEEM OVERDONE WITH RESPECT TO
VERY SUBTLE FORCING MECHANISMS. AGAIN...WEEDING THROUGH THE
CONVECTIVE FEEDBACK PROBLEMS AS BOTH MODELS TRY TO LIFT SOUTHERN
PLAINS CONVECTIVE VORTS THROUGH OUR REGION OVERNIGHT...WE ARE
AGAIN HARD PRESSED TO FIND SIGNIFICANT SYNOPTIC SUPPORT FOR AS
MUCH RAIN AS THESE MODELS ARE CRANKING OUT ON US. THAT SAID...THE
SFC FRONT WILL BE MOVING INTO THE REGION AND THERE IS A
POSSIBILITY THAT SOME MINOR UPPER LEVEL FEATURE COULD RUN FAST
THROUGH THE REGION. BOTH MODELS ALSO HINT AT AN INCRG SOUTHERLY
LOW LEVEL JET IMPINGING ON THE FRONTAL ZONE AND OUR HIGHER TERRAIN
AREAS IN NEPA/SENY LATE TONIGHT. WITHOUT MAKING TOO DRAMATIC A
SWING IN THE FORECAST...HAVE LOWERED SOME OF THE PREVIOUS FORECAST
POPS FOR TONIGHT AND FRIDAY...BUT HAVE MAINTAINED THE LIKELY
TERMINOLOGY AS THERE JUST DOESN`T SEEM TO BE MUCH THERE TO WARRANT
WIDESPREAD AREAS OF SHOWERS/TSRA. ALSO SHIFTED THE AXIS OF HIGHER
POPS A BIT WESTWARD TO LINE UP BETTER WITH THE FRONTAL MOVEMENT.
THE FOCUS ON THE SOUTHEAST ZONES JUST SEEMS UNREALISTIC AND THE
GFS SEEMED TO HAVE TRENDED A BIT WEST THIS RUN WITH NAM MORE IN
OUR EASTERN ZONES.
THE TRENDS THEN SUPPORT THE FRONT TO MOVE EAST OF THE REGION
FRIDAY NIGHT WITH DECREASING PRECIP PROBABILITY FROM WEST TO EAST
THROUGH THE DAY FRIDAY AND EVENTUALLY A DRY OVERNIGHT INTO SATURDAY.
HIGH PRESSURE AND COOL NORTHWESTERLY FLOW OVERSPREADS THE REGION
THIS WEEKEND. BEST CHANCE FOR SUNSHINE LOOKS TO BE SUNDAY AS COLD
ADVECTION CLOUDS ON THE FIRST DAY (SATURDAY) BEHIND A COLD FROPA
HERE SPELLS STRATOCU FIELDS GALORE AND PARTLY TO MOSTLY CLOUDY
CONDITIONS.
FOLLOWED MOS AND 2M MODEL BLENDED TEMPS ALONG WITH PREVIOUS
FORECAST WHICH HELPED TO COOL THINGS SLIGHTLY ON FRIDAY AND
SATURDAY FROM PREV FORECAST. THE TREND ON SATURDAY WILL CERTAINLY
FIT THE CLOUD IDEA.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
4 AM UPDATE...
VERY FEW CHANGES MADE TO INHERITED GRIDS AS GOOD AGREEMENT BETWEEN
THE GFS AND ECMWF SUPPORTS BETTER THAN AVERAGE CONFIDENCE THROUGH
THE PERIOD. UPPER PATTERN THROUGH THE TIME FRAME WILL BE DOMINATED
BY BROAD CYCLONIC FLOW ALOFT AS A BLOCKY MID-LATITUDE PATTERN
PERSISTS THANKS TO STRONG HIGH PRESSURE ACROSS THE NORTHERN ATLANTIC
AND CANADIAN PRAIRIE PROVINCES. BOTH THE GFS AND ECMWF AGREE THAT A
SECOND UPPER LOW WILL SWING SOUTH FROM HUDSON BAY BY LATE MON/EARLY
TUESDAY WHICH WILL SEND A COLD FRONT EAST ACROSS OUR REGION AS LOW
PRESSURE TRACKS JUST OFF TO OUR NORTH. THUS EXPECT RENEWED SHWR AND
THUNDERSTORM CHANCES BY TUESDAY BEFORE DRY WX RETURNS TO CONCLUDE
THE PERIOD. BELOW NORMAL TEMPS EXPECTED WITH NO HINTS OF ANY MAJOR
WARMING SEEN FOR THE FORESEEABLE FUTURE.
200 PM UPDATE...
AREA REMAINS UNDER A BROAD LONG WAVE UPPER LEVEL TROUGH THROUGH
THE PERIOD AND SLIGHTLY COOLER THAN NORMAL TEMPERATURES WITH HIGHS
IN LOWER TO MIDDLE 70S AND NIGHTTIME LOWS IN THE 50S.
A FRONT THAT MOVED THROUGH THE AREA EARLY SATURDAY IS FORECAST TO
STALL IN A EAST-WEST MANNER ACROSS VIRGINA SATURDAY NIGHT INTO
SUNDAY. FROM THIS POINT MODELS HAVE DIFFERENCES OF TIMING AND
POSITIONING OF WAVES MOVING EASTWARD ALONG THIS FRONT THROUGH
MIDWEEK CAUSING SOME UNCERTAINTY IN THE FORECAST.
FORECASTED CLOUDS TO SPREAD NORTH WITH A WAVE ON SUNDAY BUT JUST
PLACED A SLIGHT CHANCE THUNDERSTORMS IN THE POCONOS FOR SUNDAY
AFTERNOON. HIGH PRESSURE BUILDS ACROSS SUNDAY NIGHT BEHIND THIS
WAVE. A SHORT-WAVE MOVING AROUND THE UPR LEVEL LOW TO OUR NORTH
MAY BRING A SLIGHT CHANCE OF SHOWERS OR THUNDERSTORMS IN THE
AFTERNOON MONDAY.
UNCERTAINTY INCREASES TUESDAY AS GFS LINKS A SHORT-WAVE MOVING
AROUND THE UPR LOW TO THE NORTH WITH A SURFACE LOW AND WAVE MOVING
NORTHEAST ALONG THAT FRONTAL ZONE AND SPREADS CLOUDS AND
PRECIPITATION NORTHEAST ACROSS THE AREA TUESDAY. ON THE OTHER HAND
THE ECMWF DOES NOT LINK A WAVE UP FROM THE SOUTH WITH JUST AN
ISOLATED CHANCE. PUT A 30 POP IN TUESDAY AFTERNOON. SURFACE HIGH
PRESSURE BUILDS IN FOR WEDNESDAY WITH A SHORTWAVE RIDGE ALOFT.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AN AREA OF SHWRS AND EMBEDDED THUNDER WILL CONTINUE MOVING EAST
THROUGH THE REGION THIS MORNING. BASED ON LATEST RADAR
TRENDS...MOST CONCENTRATED ACTIVITY WILL PREVAIL FROM THE CENTRAL
FINGER LAKES SOUTH THROUGH THE TWIN TIERS WHERE TEMPORARY MVFR AND
POTENTIALLY SOME SHORT DURATION IFR WILL BE POSSIBLE. ELSEWHERE
AT SYR AND RME...CURRENT ACTIVITY WILL LIKELY POSE LITTLE IF ANY
RESTRICTIONS AS HEAVIEST RAINS REMAIN SOUTH. A LITTLE MORE
UNCERTAIN DOWN AT AVP AS A FAIR AMOUNT OF LAND STILL NEEDS TO BE
COVERED BEFORE REACHING THE TERMINAL. FOR NOW...HAVE INSERTED A
TEMPO GROUP STARTING AT 14Z FOR POSSIBLE MVFR RESTRICTIONS.
AFTER THIS PASSES...FCST BECOMES MUCH MORE CONVOLUTED AS MODELS
CONTINUE TO SHOW SEVERAL CLUSTERS OF SHWRS/STORMS DEVELOPING AFTER
THE 18Z TIME FRAME. FOR NOW...HAVE DECIDED TO OFFER A TEMPO TSRA
MENTION EVERYWHERE BETWEEN 18-21Z UNDER THE PREMISE THAT DAYSHIFT
CAN UPDATE ONCE TRENDS BEHIND THIS MORNING/S DEPARTING WAVE BECOME
A LITTLE MORE CERTAIN. BY TONIGHT...MAIN ACTIVITY TO LIKELY
IMPACT AVP AS ADDITIONAL MOISTURE BEGINS WORKING NORTH ALONG A
COLD FRONT. ELSEWHERE...WIDESPREAD MVFR RESTRICTIONS EXPECTED TO
DEVELOP WITH OCCASIONAL IFR POSSIBLE AT BGM AND ITH AS MOISTURE
BECOMES TRAPPED BELOW DEVELOPING FRONTAL INVERSION.
OUTLOOK...
FRI...VFR BUT MVFR IN SCATTERED SHRA/TSRA MAINLY SOUTH.
SAT THRU MON...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JAB
NEAR TERM...
SHORT TERM...JAB
LONG TERM...BMW/CMG
AVIATION...CMG
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
405 AM EDT THU AUG 8 2013
.SYNOPSIS...
A SLOW MOVING COLD FRONT WILL EVENTUALLY MOVE PAST THE REGION ON
FRIDAY NIGHT. IN THE MEANTIME...CHANCES FOR PERIODIC SHOWERS AND
A THUNDERSTORM OR TWO WILL CONTINUE FOR TODAY AND FRIDAY. A DRIER
WEEKEND IS IN STORE WITH TEMPERATURES REMAINING ON THE COOLER SIDE
OF NORMAL FOR AUGUST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
TODAY WILL BE A CRAZY...CONVOLUTED AND LOW CONFIDENCE FORECAST
GIVEN THE NATURE OF ZONAL FLOW PATTERNS IN THE SUMMER MONTHS. THE
FIRST ORDER OF BUSINESS WITH THIS MORNING`S UPDATE IS TO TRACK
AND TIME THE CONVECTION MOVING THROUGH WESTERN NEW YORK AND IT`S
IMPACT HERE IN CENTRAL DURING THE EARLY HOURS. CONVECTION LOOKS TO
BE MAINLY DRIVEN NOW BY COLD POOL INTERACTION WITHIN A BROAD
UNSTABLE ENVIRONMENT...AS WV LOOP SHOWS INITIATING SHORT WAVE IS
RUNNING OUT AHEAD OF THE CONVECTION ACROSS LOWER ONTARIO. LINEAR
TRACKING TAKES THE RAIN AND EMBEDDED TSRA ACROSS MAINLY THE FINGER
LAKES REGION AND NORTHERN PORTIONS OF THE SOUTHERN TIER DURING THE
EARLY DAYLIGHT HOURS AND HAVE ACCOUNTED FOR THIS WITH ABOUT 4-6
HOURS OF CATEGORICAL-LIKELY POPS OVER NORTHERN COUNTIES WITH SOME
SLACK ON THE SOUTHERN END OF THE POP FIELD FOR NEW DEVELOPMENT.
THINK THERE WILL ALSO CONTINUE TO BE WEAKENING OF THIS FEATURE AS
THE MORNING WEARS ON.
THEN...ATTENTION TURNS TO SLOWLY APPROACHING FRONTAL BOUNDARY FOR
LATER THIS AFTERNOON. AFTER SCOURING MANY MODEL SOLUTIONS...AND
PICKING THROUGH THE NOISE OF CONVECTIVE FEEDBACK...WE ARE HARD
PRESSED TO FIND MUCH IN THE WAY OF FORCING FOR NEW CONVECTION THIS
AFTERNOON ASIDE FROM MINOR HEIGHT AND PRESSURE FALLS ASSOCIATED
WITH THE FRONTAL BOUNDARY...FORMING IN TANDEM WITH DECREASING
DIURNAL STABILITY. THE MESOSCALE MODELS LIKE THE HRRR AND WRF-ARW
CONVECT MAINLY ALONG THE FRONTAL BOUNDARY MOVING INTO WRN NY THIS
AFTENROON WITH SPOTTY ACTIVITY IN OUR ARAE. WE THEREFORE FEEL MUCH
OF THE DAY WILL FEATURE...AT BEST... SCATTERED NEW CONVECTIVE
DEVELOPMENT ONCE THIS LINGERING RAIN FEATURE MAKES ITS WAY THROUGH
OR DISSIPATES IN THE PROCESS. HAVE THUS SCALED BACK ON ANY LIKELY
POPS WE HAD GOING THIS AFTERNOON.
OTHER PARAMETERS ARE FAIRLY ROUTINE. TEMPERATURES AS A BLEND OF
PREV FORECAST/00Z MOS AND 2M MODEL TEMPS AND LOOK TO BE MAINLY IN
THE UPPER 70S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
THE FORECAST GETS NO EASIER TONIGHT WITH FRONT ONLY SAGGING INTO
THE REGION. 00Z NAM AND GFS ARE SIMILAR IN FRONTAL PLACEMENT AND
UPPER AIR MASS FIELDS...BUT THE RESULTANT QPF FIELDS ARE VERY
DIFFERENT TONIGHT AND FRIDAY AND SEEM OVERDONE WITH RESPECT TO
VERY SUBTLE FORCING MECHANISMS. AGAIN...WEEDING THROUGH THE
CONVECTIVE FEEDBACK PROBLEMS AS BOTH MODELS TRY TO LIFT SOUTHERN
PLAINS CONVECTIVE VORTS THROUGH OUR REGION OVERNIGHT...WE ARE
AGAIN HARD PRESSED TO FIND SIGNIFICANT SYNOPTIC SUPPORT FOR AS
MUCH RAIN AS THESE MODELS ARE CRANKING OUT ON US. THAT SAID...THE
SFC FRONT WILL BE MOVING INTO THE REGION AND THERE IS A
POSSIBILITY THAT SOME MINOR UPPER LEVEL FEATURE COULD RUN FAST
THROUGH THE REGION. BOTH MODELS ALSO HINT AT AN INCRG SOUTHERLY
LOW LEVEL JET IMPINGING ON THE FRONTAL ZONE AND OUR HIGHER TERRAIN
AREAS IN NEPA/SENY LATE TONIGHT. WITHOUT MAKING TOO DRAMATIC A
SWING IN THE FORECAST...HAVE LOWERED SOME OF THE PREVIOUS FORECAST
POPS FOR TONIGHT AND FRIDAY...BUT HAVE MAINTAINED THE LIKELY
TERMINOLOGY AS THERE JUST DOESN`T SEEM TO BE MUCH THERE TO WARRANT
WIDESPREAD AREAS OF SHOWERS/TSRA. ALSO SHIFTED THE AXIS OF HIGHER
POPS A BIT WESTWARD TO LINE UP BETTER WITH THE FRONTAL MOVEMENT.
THE FOCUS ON THE SOUTHEAST ZONES JUST SEEMS UNREALISTIC AND THE
GFS SEEMED TO HAVE TRENDED A BIT WEST THIS RUN WITH NAM MORE IN
OUR EASTERN ZONES.
THE TRENDS THEN SUPPORT THE FRONT TO MOVE EAST OF THE REGION
FRIDAY NIGHT WITH DECREASING PRECIP PROBABILITY FROM WEST TO EAST
THROUGH THE DAY FRIDAY AND EVENTUALLY A DRY OVERNIGHT INTO SATURDAY.
HIGH PRESSURE AND COOL NORTHWESTERLY FLOW OVERSPREADS THE REGION
THIS WEEKEND. BEST CHANCE FOR SUNSHINE LOOKS TO BE SUNDAY AS COLD
ADVECTION CLOUDS ON THE FIRST DAY (SATURDAY) BEHIND A COLD FROPA
HERE SPELLS STRATOCU FIELDS GALORE AND PARTLY TO MOSTLY CLOUDY
CONDITIONS.
FOLLOWED MOS AND 2M MODEL BLENDED TEMPS ALONG WITH PREVIOUS
FORECAST WHICH HELPED TO COOL THINGS SLIGHTLY ON FRIDAY AND
SATURDAY FROM PREV FORECAST. THE TREND ON SATURDAY WILL CERTAINLY
FIT THE CLOUD IDEA.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
4 AM UPDATE...
VERY FEW CHANGES MADE TO INHERITED GRIDS AS GOOD AGREEMENT BETWEEN
THE GFS AND ECMWF SUPPORTS BETTER THAN AVERAGE CONFIDENCE THROUGH
THE PERIOD. UPPER PATTERN THROUGH THE TIME FRAME WILL BE DOMINATED
BY BROAD CYCLONIC FLOW ALOFT AS A BLOCKY MID-LATITUDE PATTERN
PERSISTS THANKS TO STRONG HIGH PRESSURE ACROSS THE NORTHERN ATLANTIC
AND CANADIAN PRAIRIE PROVINCES. BOTH THE GFS AND ECMWF AGREE THAT A
SECOND UPPER LOW WILL SWING SOUTH FROM HUDSON BAY BY LATE MON/EARLY
TUESDAY WHICH WILL SEND A COLD FRONT EAST ACROSS OUR REGION AS LOW
PRESSURE TRACKS JUST OFF TO OUR NORTH. THUS EXPECT RENEWED SHWR AND
THUNDERSTORM CHANCES BY TUESDAY BEFORE DRY WX RETURNS TO CONCLUDE
THE PERIOD. BELOW NORMAL TEMPS EXPECTED WITH NO HINTS OF ANY MAJOR
WARMING SEEN FOR THE FORESEEABLE FUTURE.
200 PM UPDATE...
AREA REMAINS UNDER A BROAD LONG WAVE UPPER LEVEL TROUGH THROUGH
THE PERIOD AND SLIGHTLY COOLER THAN NORMAL TEMPERATURES WITH HIGHS
IN LOWER TO MIDDLE 70S AND NIGHTTIME LOWS IN THE 50S.
A FRONT THAT MOVED THROUGH THE AREA EARLY SATURDAY IS FORECAST TO
STALL IN A EAST-WEST MANNER ACROSS VIRGINA SATURDAY NIGHT INTO
SUNDAY. FROM THIS POINT MODELS HAVE DIFFERENCES OF TIMING AND
POSITIONING OF WAVES MOVING EASTWARD ALONG THIS FRONT THROUGH
MIDWEEK CAUSING SOME UNCERTAINTY IN THE FORECAST.
FORECASTED CLOUDS TO SPREAD NORTH WITH A WAVE ON SUNDAY BUT JUST
PLACED A SLIGHT CHANCE THUNDERSTORMS IN THE POCONOS FOR SUNDAY
AFTERNOON. HIGH PRESSURE BUILDS ACROSS SUNDAY NIGHT BEHIND THIS
WAVE. A SHORT-WAVE MOVING AROUND THE UPR LEVEL LOW TO OUR NORTH
MAY BRING A SLIGHT CHANCE OF SHOWERS OR THUNDERSTORMS IN THE
AFTERNOON MONDAY.
UNCERTAINTY INCREASES TUESDAY AS GFS LINKS A SHORT-WAVE MOVING
AROUND THE UPR LOW TO THE NORTH WITH A SURFACE LOW AND WAVE MOVING
NORTHEAST ALONG THAT FRONTAL ZONE AND SPREADS CLOUDS AND
PRECIPITATION NORTHEAST ACROSS THE AREA TUESDAY. ON THE OTHER HAND
THE ECMWF DOES NOT LINK A WAVE UP FROM THE SOUTH WITH JUST AN
ISOLATED CHANCE. PUT A 30 POP IN TUESDAY AFTERNOON. SURFACE HIGH
PRESSURE BUILDS IN FOR WEDNESDAY WITH A SHORTWAVE RIDGE ALOFT.
&&
.AVIATION /07Z THURSDAY THROUGH MONDAY/...
VERY DIFFICULT FCST THIS MORNING AS LATEST SATELLITE AND
OBSERVATION TRENDS HAVE SHOWN A NOTABLE DECREASE IN LOW STRATUS
ACROSS THE REGION OVER THE PAST FEW HRS. ADDITIONALLY...CONVECTION
NOW ENTERING THE GREATER BUFFALO METRO WILL CONTINUE WORKING EAST
OVERNIGHT WITH POSSIBLE IMPACTS AT BOTH ELM AND ITH BY 10Z OR SO.
THAT SAID...HAVE DELAYED IFR MENTION AT BGM FOR A FEW HRS BASED ON
LATEST TRENDS...HOWEVER CONCERNS ARE THAT LOW CLOUDS WILL FILL
BACK IN AS WE PROGRESS THROUGH THE EARLY MORNING. IF THIS DOES
OCCUR...WE MAINLY EXPECT MVFR CONDITIONS AT REMAINING FCST LOCATIONS.
AFTER 12Z...FCST BECOMES MORE CLOUDED AS WEAK TO MODERATE
INSTABILITY DEVELOPS OVER THE REGION. ITS NEARLY IMPOSSIBLE TO
DISCERN ANY SPECIFIC TIMING AS THERE REMAINS VERY LITTLE IN THE
WAY OF ANY APPRECIABLE FORCING MECHANISMS. FOR NOW...WILL CONTINUE
WITH EARLIER LINE OF THINKING WITH POSSIBLE SHWRS/STORMS
DEVELOPING ALONG AND EAST OF THE I-81 CORRIDOR LATER THIS AFTERNOON.
RAIN TO LIKELY CONTINUE INTO THE EVENING HRS...ESPECIALLY AT AVP
AS NEXT SFC WAVE WORKS NORTH WITH TIME.
OUTLOOK...
FRI...VFR BUT MVFR IN SCATTERED SHRA/TSRA MAINLY SOUTH.
SAT THRU MON...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JAB
NEAR TERM...
SHORT TERM...JAB
LONG TERM...BMW/CMG
AVIATION...CMG
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
341 AM EDT THU AUG 8 2013
.SYNOPSIS...
SOUTHERLY FLOW WILL PERSIST ACROSS THE NORTH COUNTRY OVERNIGHT
THROUGH THURSDAY WITH A CHANCE OF RAIN SHOWERS OVERNIGHT AND A
CHANCE OF SHOWERS AND THUNDERSTORMS ON THURSDAY. A COLD FRONT WILL
MOVE INTO THE REGION ON FRIDAY BRINGING MORE SHOWERS AND THUNDERSTORMS
TO THE NORTH COUNTRY. SOME THUNDERSTORMS ON FRIDAY COULD PRODUCE
LOCALLY HEAVY RAINFALL. A RIDGE OF HIGH PRESSURE WILL BUILD INTO
THE NORTH COUNTRY ON FRIDAY NIGHT AND WILL BRING FAIR AND DRY
WEATHER TO THE REGION THIS WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1223 AM EDT THURSDAY...CURRENT FORECAST IN GREAT SHAPE AND
ONLY MINOR ADJUSTMENTS TO T/TD/MIN TEMP DATASETS AS OF THE
MIDNIGHT HOUR. SCT CONVECTION ALONG PRE-FRONTAL TROUGH HAVING A
HARD TIME MAKING IT INTO OUR REGION AND TRUDGING SLOWLY EAST FROM
ONTARIO/OTTAWA VALLEY ATTM. INDEED...LATEST CAM MODEL RUNS
ACTUALLY SHOWING MUCH OF THIS ACTIVITY EITHER WANING OR SPLITTING
NORTH AND/OR SOUTH OF OUR AREA OVERNIGHT LEAVING MANY AREAS DRY.
THUS PRIOR IDEA OF LOWERING POPS TO CHANCE (30/40 PCT) LOOKS RIGHT
ON TRACK. TEMPERATURES WILL REMAIN MILD AND HOLD GENERALLY IN THE
60S TO LOCALLY NEAR 70 IN THE CHAMPLAIN VALLEY AS LIGHT TO
MODERATE SOUTH FLOW CONTINUES. HAVE A GREAT NIGHT. PRIOR
DISCUSSION FOLLOWS...
BASED ON CURRENT RADAR AND RECENT NAM/RAP/HRRR GUIDANCE TRENDS
HAVE MADE FAIRLY SIGNIFICANT DOWNWARD TWEAKS TO POPS TONIGHT INTO
THURSDAY MORNING. ASIDE FOR SOME SHOWERS THAT HAD MOVED ACROSS THE
NORTHERN CHAMPLAIN VALLEY INTO NORTHERN VERMONT...STEADIER/HEAVIER
SHOWERS AND THUNDERSTORMS REMAIN ACROSS EASTERN ONTARIO AND THE
NORTHERN SHORE OF LAKE ONTARIO. THE RADAR RETURNS ACROSS THE SAINT
LAWRENCE VALLEY ARE MERELY ANVIL SHADOWS...AND RECENT TRENDS SHOW
BETTER CONVECTIVE DEVELOPMENT TRAILING BACK ALONG THE NORTHERN
SHORE OF LAKE ONTARIO IN THE VICINITY OF THE TORONTO AREA. AS
MENTIONED...FEEL THAT THE NAM...RAP AND HRRR MODELS ARE CURRENTLY
HANDLING PRESENT CONDITIONS THE BEST AND HAVE THEREFORE ALIGNED
THE FORECAST CLOSER TO THAT SUITE OF GUIDANCE. SPECULATING THAT
OTHER WETTER GUIDANCE...E.G. THE GFS...MAY HAVE BEEN KEYING ON
DEEPER MOISTURE FEED WHICH THE EARLIER MCS OVER PA MAY HAVE TAPPED
INTO. NEVERTHELESS...STILL EXPECT SFC COLD FRONT ACROSS ONTARIO TO
APPROACH THE NORTH COUNTRY THROUGH OVERNIGHT BUT WILL ONLY BE
GOING WITH CHANCE TO HIGH CHANCE POPS THROUGH SUNRISE...AND THEN
SLIGHT CHANCE TO CHANCE THROUGH THE THURSDAY MORNING PERIOD.
CURRENT TEMPS/DEWPOINTS STILL LOOK ON TRACK AND IT SHOULD
OTHERWISE BE A CLOUDY...MILDER AND SLIGHTLY MORE HUMID NIGHT THAN
RECENTLY WITH LOWS IN THE UPPER 50S TO THE 60S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY/...
AS OF 428 PM EDT WEDNESDAY...ON THURSDAY MODELS SHOW MOISTURE
STREAMING NORTHEASTWARD INTO THE REGION FROM THE OHIO VALLEY.
CONDITIONS DESTABILIZE DURING THE DAY ON THURSDAY...SO HAVE GONE
WITH LIKELY POPS FOR SHOWERS AND THUNDERSTORMS. EXPECTING THIS
ACTIVITY TO CONTINUE INTO THURSDAY NIGHT. MOISTURE WILL CONTINUE
TO STREAM INTO THE REGION ON FRIDAY WITH PRECIPITABLE WATER VALUES
APPROACHING 2 INCHES. HAVE ADDED ENHANCED WORDING TO THE FORECAST
TO MENTION LOCALLY HEAVY RAINFALL POSSIBLE ON FRIDAY. A COLD FRONT
WILL MOVE THROUGH THE REGION DURING THE DAY ON FRIDAY. DRIER AIR
WORKING INTO THE REGION FRIDAY NIGHT AFTER THE COLD FRONTAL
PASSAGE. EXPECTING SHOWER AND THUNDERSTORM ACTIVITY TO DIMINISH
EARLY FRIDAY EVENING.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 341 AM EDT THURSDAY...ELONGATED AREA OF SFC HIGH PRESSURE
STRETCHING FROM THE GREAT LKS REGION TO THE EAST COAST FOR THE
SAT NGT-MONDAY MORNING PERIOD W/ END RESULT OF RIDGE SHIFTING
OFFSHORE THRU THE DAY MONDAY. EXPECTING NICE STRETCH OF WX OVER
THE UPCOMING WEEKEND AS A RESULT. THE NORTH COUNTRY WILL FEEL THE
EFFECTS OF BROAD UPPER LOW OVER EASTERN CANADA. ANOTHER LOW
PINWHEELING AROUND THIS SYSTEM WILL DIVE SE THRU THE GREAT LKS
MONDAY AND ACROSS THE NORTHEAST REGION INTO MIDWEEK. ZONAL
MIDLEVEL FLOW COMBINED WITH SOUTHERLY WINDS AT THE SFC...WILL
ALLOW FOR SLOW MVMNT THRU AREA AND WILL BRING AMPLE POTENTIAL QPF
AS A RESULT OF SSW FLOW. WILL BE CARRYING -RW FOR THE LATTER
PORTION OF EXTENDED INTO EARLY TUESDAY EVENING BFR SFC RIDGE
RETURNS FROM THE WEST DRYING REGION OUT AGAIN WED INTO THURS.
TEMPS NEAR NORMAL THRU PERIOD WITH HIGHS RANGING IN THE MID TO
UPPER 70S AND LOWS IN THE 40S TO L50S. PRECIP/CLD COVER MONDAY NGT
INTO TUESDAY COULD HAMPER TEMPS.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
THROUGH 06Z FRIDAY...SCT -RW WITH SOME POSSIBLE FG THRU 12Z
THURSDAY WILL BRING MVFR COND WITH VSBY DOWN TO 3-6SM AT TIMES AND
CEILINGS DOWN TO BKN025-030 AT TIMES. FROM 12Z THURSDAY VFR
CONDITIONS WITH CEILINGS BKN040-060 AND VCSH. CHANCE FOR TRW TO
DEVELOP LATE IN AFTNOON INTO EVENING HRS. AFT 00Z FRI...SOME MVFR
FG FOR SLK/MPV ALONG WITH CHANCE FOR RW/TRW AS BOUNDARY PUSHES
THRU REGION. WINDS SSW 10-20KTS WITH GUSTS NEAR 30KTS FOR BTV.
LGT/VAR FOR MPV/SLK AFT 00Z FRI.
OUTLOOK 06Z FRIDAY THROUGH MONDAY...
06Z FRIDAY THROUGH 00Z SATURDAY...VFR WITH OCCASIONAL MVFR/IFR IN
SHOWERS/THUNDERSTORMS AS A WARM/OCCLUDED FRONT LIFTS ACROSS THE
AREA.
00Z SATURDAY THROUGH MONDAY...MAINLY VFR UNDER SURFACE HIGH PRESSURE.
&&
.MARINE...
A LAKE WIND ADVISORY IS IN EFFECT THROUGH EARLY THURSDAY MORNING. SOUTH
WINDS WILL INCREASE THIS EVENING TO 15 TO 25 KNOTS...PEAKING
AROUND MIDNIGHT WITH SOME GUSTS UP TO 30 KNOTS..ESPECIALLY ACROSS
THE OPEN WATERS OF CENTRAL AND NORTHERN LAKE CHAMPLAIN. WINDS
WILL GRADUALLY DECREASE TOWARDS THURSDAY MORNING WITH SOUTH WINDS
FROM 10 TO 20 KNOTS EXPECTED ON THURSDAY. THESE WINDS WILL CREATE
WAVES OF 2 TO 4 FEET ON THE BROAD LAKE...ESPECIALLY ACROSS THE
CENTRAL AND NORTHERN PORTIONS. WAVE HEIGHTS WILL DECREASE TO 1 TO
3 FEET FOR THURSDAY. IN ADDITION...SCATTERED SHOWERS AND POSSIBLE
THUNDERSTORMS MAY AFFECT THE AREA TONIGHT THROUGH THURSDAY...WITH
MORE WIDESPREAD SHOWERS AND THUNDERSTORMS LIKELY LATE THURSDAY
NIGHT AND INTO FRIDAY.
&&
.EQUIPMENT...
AS OF 456 PM EDT WEDNESDAY...THE KTYX 88D DOPPLER RADAR IN
NORTHERN NEW YORK HAS BEEN RESTORED TO SERVICE. SOME ADDITIONAL
WORK ON THIS RADAR WILL NEED TO BE DONE ON THURSDAY.
AS OF 350 AM EDT WEDNESDAY...NOAA WEATHER RADIO STATION WXM 44...
BROADCASTING FROM THE TOP OF MOUNT ASCUTNEY VERMONT...REMAINS OFF
THE AIR UNTIL FURTHER NOTICE DUE TO A DAMAGED ANTENNA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...WGH
NEAR TERM...JMG/LOCONTO
SHORT TERM...WGH
LONG TERM...JN
AVIATION...LAHIFF/JN
MARINE...BTV
EQUIPMENT...BTV
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
139 AM EDT THU AUG 8 2013
.SYNOPSIS...
SOUTHERLY FLOW WILL PERSIST ACROSS THE NORTH COUNTRY OVERNIGHT
THROUGH THURSDAY WITH A CHANCE OF RAIN SHOWERS OVERNIGHT AND A
CHANCE OF SHOWERS AND THUNDERSTORMS ON THURSDAY. A COLD FRONT WILL
MOVE INTO THE REGION ON FRIDAY BRINGING MORE SHOWERS AND THUNDERSTORMS
TO THE NORTH COUNTRY. SOME THUNDERSTORMS ON FRIDAY COULD PRODUCE
LOCALLY HEAVY RAINFALL. A RIDGE OF HIGH PRESSURE WILL BUILD INTO
THE NORTH COUNTRY ON FRIDAY NIGHT AND WILL BRING FAIR AND DRY
WEATHER TO THE REGION THIS WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1223 AM EDT THURSDAY...CURRENT FORECAST IN GREAT SHAPE AND
ONLY MINOR ADJUSTMENTS TO T/TD/MIN TEMP DATASETS AS OF THE
MIDNIGHT HOUR. SCT CONVECTION ALONG PRE-FRONTAL TROUGH HAVING A
HARD TIME MAKING IT INTO OUR REGION AND TRUDGING SLOWLY EAST FROM
ONTARIO/OTTAWA VALLEY ATTM. INDEED...LATEST CAM MODEL RUNS
ACTUALLY SHOWING MUCH OF THIS ACTIVITY EITHER WANING OR SPLITTING
NORTH AND/OR SOUTH OF OUR AREA OVERNIGHT LEAVING MANY AREAS DRY.
THUS PRIOR IDEA OF LOWERING POPS TO CHANCE (30/40 PCT) LOOKS RIGHT
ON TRACK. TEMPERATURES WILL REMAIN MILD AND HOLD GENERALLY IN THE
60S TO LOCALLY NEAR 70 IN THE CHAMPLAIN VALLEY AS LIGHT TO
MODERATE SOUTH FLOW CONTINUES. HAVE A GREAT NIGHT. PRIOR
DISCUSSION FOLLOWS...
BASED ON CURRENT RADAR AND RECENT NAM/RAP/HRRR GUIDANCE TRENDS
HAVE MADE FAIRLY SIGNIFICANT DOWNWARD TWEAKS TO POPS TONIGHT INTO
THURSDAY MORNING. ASIDE FOR SOME SHOWERS THAT HAD MOVED ACROSS THE
NORTHERN CHAMPLAIN VALLEY INTO NORTHERN VERMONT...STEADIER/HEAVIER
SHOWERS AND THUNDERSTORMS REMAIN ACROSS EASTERN ONTARIO AND THE
NORTHERN SHORE OF LAKE ONTARIO. THE RADAR RETURNS ACROSS THE SAINT
LAWRENCE VALLEY ARE MERELY ANVIL SHADOWS...AND RECENT TRENDS SHOW
BETTER CONVECTIVE DEVELOPMENT TRAILING BACK ALONG THE NORTHERN
SHORE OF LAKE ONTARIO IN THE VICINITY OF THE TORONTO AREA. AS
MENTIONED...FEEL THAT THE NAM...RAP AND HRRR MODELS ARE CURRENTLY
HANDLING PRESENT CONDITIONS THE BEST AND HAVE THEREFORE ALIGNED
THE FORECAST CLOSER TO THAT SUITE OF GUIDANCE. SPECULATING THAT
OTHER WETTER GUIDANCE...E.G. THE GFS...MAY HAVE BEEN KEYING ON
DEEPER MOISTURE FEED WHICH THE EARLIER MCS OVER PA MAY HAVE TAPPED
INTO. NEVERTHELESS...STILL EXPECT SFC COLD FRONT ACROSS ONTARIO TO
APPROACH THE NORTH COUNTRY THROUGH OVERNIGHT BUT WILL ONLY BE
GOING WITH CHANCE TO HIGH CHANCE POPS THROUGH SUNRISE...AND THEN
SLIGHT CHANCE TO CHANCE THROUGH THE THURSDAY MORNING PERIOD.
CURRENT TEMPS/DEWPOINTS STILL LOOK ON TRACK AND IT SHOULD
OTHERWISE BE A CLOUDY...MILDER AND SLIGHTLY MORE HUMID NIGHT THAN
RECENTLY WITH LOWS IN THE UPPER 50S TO THE 60S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/...
AS OF 428 PM EDT WEDNESDAY...ON THURSDAY MODELS SHOW MOISTURE
STREAMING NORTHEASTWARD INTO THE REGION FROM THE OHIO VALLEY.
CONDITIONS DESTABILIZE DURING THE DAY ON THURSDAY...SO HAVE GONE
WITH LIKELY POPS FOR SHOWERS AND THUNDERSTORMS. EXPECTING THIS
ACTIVITY TO CONTINUE INTO THURSDAY NIGHT. MOISTURE WILL CONTINUE
TO STREAM INTO THE REGION ON FRIDAY WITH PRECIPITABLE WATER VALUES
APPROACHING 2 INCHES. HAVE ADDED ENHANCED WORDING TO THE FORECAST
TO MENTION LOCALLY HEAVY RAINFALL POSSIBLE ON FRIDAY. A COLD FRONT
WILL MOVE THROUGH THE REGION DURING THE DAY ON FRIDAY. DRIER AIR
WORKING INTO THE REGION FRIDAY NIGHT AFTER THE COLD FRONTAL
PASSAGE. EXPECTING SHOWER AND THUNDERSTORM ACTIVITY TO DIMINISH
EARLY FRIDAY EVENING.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 341 PM EDT WEDNESDAY...THE EXTENDED PORTION OF THE FORECAST
WILL FEATURE PRETTY QUIET AND COOL WEATHER...NO SIGNIFICANT
CHANCES FOR PRECIPITATION. UPPER LEVEL LOW LIFTS NORTHEAST AND
AWAY FROM THE NORTH COUNTRY SATURDAY AND A RIDGE OF SURFACE HIGH
PRESSURE BUILDS INTO THE AREA. MAINLY DRY WEATHER IS EXPECTED
FROM SATURDAY THROUGH MONDAY. A LOW PRESSURE SYSTEM PASSING NORTH
OF OUR REGION ON MONDAY NIGHT WILL BRING A CHANCE FOR SOME
SHOWERS...THOUGH BEST DYNAMICS REMAIN WELL NORTH OF OUR FORECAST
AREA. TUESDAY THROUGH WEDNESDAY WILL ALSO BE QUIET WITH ANOTHER
RIDGE OF HIGH PRESSURE BUILDING INTO THE AREA.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
THROUGH 06Z FRIDAY...SCT -RW WITH SOME POSSIBLE FG THRU 12Z
THURSDAY WILL BRING MVFR COND WITH VSBY DOWN TO 3-6SM AT TIMES AND
CEILINGS DOWN TO BKN025-030 AT TIMES. FROM 12Z THURSDAY VFR
CONDITIONS WITH CEILINGS BKN040-060 AND VCSH. CHANCE FOR TRW TO
DEVELOP LATE IN AFTNOON INTO EVENING HRS. AFT 00Z FRI...SOME MVFR
FG FOR SLK/MPV ALONG WITH CHANCE FOR RW/TRW AS BOUNDARY PUSHES
THRU REGION. WINDS SSW 10-20KTS WITH GUSTS NEAR 30KTS FOR BTV.
LGT/VAR FOR MPV/SLK AFT 00Z FRI.
OUTLOOK 06Z FRIDAY THROUGH MONDAY...
06Z FRIDAY THROUGH 00Z SATURDAY...VFR WITH OCCASIONAL MVFR/IFR IN
SHOWERS/THUNDERSTORMS AS A WARM/OCCLUDED FRONT LIFTS ACROSS THE
AREA.
00Z SATURDAY THROUGH MONDAY...MAINLY VFR UNDER SURFACE HIGH PRESSURE.
&&
.MARINE...
A LAKE WIND ADVISORY IS IN EFFECT THROUGH EARLY THURSDAY MORNING. SOUTH
WINDS WILL INCREASE THIS EVENING TO 15 TO 25 KNOTS...PEAKING
AROUND MIDNIGHT WITH SOME GUSTS UP TO 30 KNOTS..ESPECIALLY ACROSS
THE OPEN WATERS OF CENTRAL AND NORTHERN LAKE CHAMPLAIN. WINDS
WILL GRADUALLY DECREASE TOWARDS THURSDAY MORNING WITH SOUTH WINDS
FROM 10 TO 20 KNOTS EXPECTED ON THURSDAY. THESE WINDS WILL CREATE
WAVES OF 2 TO 4 FEET ON THE BROAD LAKE...ESPECIALLY ACROSS THE
CENTRAL AND NORTHERN PORTIONS. WAVE HEIGHTS WILL DECREASE TO 1 TO
3 FEET FOR THURSDAY. IN ADDITION...SCATTERED SHOWERS AND POSSIBLE
THUNDERSTORMS MAY AFFECT THE AREA TONIGHT THROUGH THURSDAY...WITH
MORE WIDESPREAD SHOWERS AND THUNDERSTORMS LIKELY LATE THURSDAY
NIGHT AND INTO FRIDAY.
&&
.EQUIPMENT...
AS OF 456 PM EDT WEDNESDAY...THE KTYX 88D DOPPLER RADAR IN
NORTHERN NEW YORK HAS BEEN RESTORED TO SERVICE. SOME ADDITIONAL
WORK ON THIS RADAR WILL NEED TO BE DONE ON THURSDAY.
AS OF 350 AM EDT WEDNESDAY...NOAA WEATHER RADIO STATION WXM 44...
BROADCASTING FROM THE TOP OF MOUNT ASCUTNEY VERMONT...REMAINS OFF
THE AIR UNTIL FURTHER NOTICE DUE TO A DAMAGED ANTENNA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...WGH
NEAR TERM...JMG/LOCONTO
SHORT TERM...WGH
LONG TERM...NEILES
AVIATION...LAHIFF/JN
MARINE...BTV
EQUIPMENT...BTV
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1223 AM EDT THU AUG 8 2013
.SYNOPSIS...
SOUTHERLY FLOW WILL PERSIST ACROSS THE NORTH COUNTRY OVERNIGHT
THROUGH THURSDAY WITH A CHANCE OF RAIN SHOWERS OVERNIGHT AND A
CHANCE OF SHOWERS AND THUNDERSTORMS ON THURSDAY. A COLD FRONT WILL
MOVE INTO THE REGION ON FRIDAY BRINGING MORE SHOWERS AND THUNDERSTORMS
TO THE NORTH COUNTRY. SOME THUNDERSTORMS ON FRIDAY COULD PRODUCE
LOCALLY HEAVY RAINFALL. A RIDGE OF HIGH PRESSURE WILL BUILD INTO
THE NORTH COUNTRY ON FRIDAY NIGHT AND WILL BRING FAIR AND DRY
WEATHER TO THE REGION THIS WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1223 AM EDT THURSDAY...CURRENT FORECAST IN GREAT SHAPE AND
ONLY MINOR ADJUSTMENTS TO T/TD/MIN TEMP DATASETS AS OF THE
MIDNIGHT HOUR. SCT CONVECTION ALONG PRE-FRONTAL TROUGH HAVING A
HARD TIME MAKING IT INTO OUR REGION AND TRUDGING SLOWLY EAST FROM
ONTARIO/OTTAWA VALLEY ATTM. INDEED...LATEST CAM MODEL RUNS
ACTUALLY SHOWING MUCH OF THIS ACTIVITY EITHER WANING OR SPLITTING
NORTH AND/OR SOUTH OF OUR AREA OVERNIGHT LEAVING MANY AREAS DRY.
THUS PRIOR IDEA OF LOWERING POPS TO CHANCE (30/40 PCT) LOOKS RIGHT
ON TRACK. TEMPERATURES WILL REMAIN MILD AND HOLD GENERALLY IN THE
60S TO LOCALLY NEAR 70 IN THE CHAMPLAIN VALLEY AS LIGHT TO
MODERATE SOUTH FLOW CONTINUES. HAVE A GREAT NIGHT. PRIOR
DISCUSSION FOLLOWS...
BASED ON CURRENT RADAR AND RECENT NAM/RAP/HRRR GUIDANCE TRENDS
HAVE MADE FAIRLY SIGNIFICANT DOWNWARD TWEAKS TO POPS TONIGHT INTO
THURSDAY MORNING. ASIDE FOR SOME SHOWERS THAT HAD MOVED ACROSS THE
NORTHERN CHAMPLAIN VALLEY INTO NORTHERN VERMONT...STEADIER/HEAVIER
SHOWERS AND THUNDERSTORMS REMAIN ACROSS EASTERN ONTARIO AND THE
NORTHERN SHORE OF LAKE ONTARIO. THE RADAR RETURNS ACROSS THE SAINT
LAWRENCE VALLEY ARE MERELY ANVIL SHADOWS...AND RECENT TRENDS SHOW
BETTER CONVECTIVE DEVELOPMENT TRAILING BACK ALONG THE NORTHERN
SHORE OF LAKE ONTARIO IN THE VICINITY OF THE TORONTO AREA. AS
MENTIONED...FEEL THAT THE NAM...RAP AND HRRR MODELS ARE CURRENTLY
HANDLING PRESENT CONDITIONS THE BEST AND HAVE THEREFORE ALIGNED
THE FORECAST CLOSER TO THAT SUITE OF GUIDANCE. SPECULATING THAT
OTHER WETTER GUIDANCE...E.G. THE GFS...MAY HAVE BEEN KEYING ON
DEEPER MOISTURE FEED WHICH THE EARLIER MCS OVER PA MAY HAVE TAPPED
INTO. NEVERTHELESS...STILL EXPECT SFC COLD FRONT ACROSS ONTARIO TO
APPROACH THE NORTH COUNTRY THROUGH OVERNIGHT BUT WILL ONLY BE
GOING WITH CHANCE TO HIGH CHANCE POPS THROUGH SUNRISE...AND THEN
SLIGHT CHANCE TO CHANCE THROUGH THE THURSDAY MORNING PERIOD.
CURRENT TEMPS/DEWPOINTS STILL LOOK ON TRACK AND IT SHOULD
OTHERWISE BE A CLOUDY...MILDER AND SLIGHTLY MORE HUMID NIGHT THAN
RECENTLY WITH LOWS IN THE UPPER 50S TO THE 60S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/...
AS OF 428 PM EDT WEDNESDAY...ON THURSDAY MODELS SHOW MOISTURE
STREAMING NORTHEASTWARD INTO THE REGION FROM THE OHIO VALLEY.
CONDITIONS DESTABILIZE DURING THE DAY ON THURSDAY...SO HAVE GONE
WITH LIKELY POPS FOR SHOWERS AND THUNDERSTORMS. EXPECTING THIS
ACTIVITY TO CONTINUE INTO THURSDAY NIGHT. MOISTURE WILL CONTINUE
TO STREAM INTO THE REGION ON FRIDAY WITH PRECIPITABLE WATER VALUES
APPROACHING 2 INCHES. HAVE ADDED ENHANCED WORDING TO THE FORECAST
TO MENTION LOCALLY HEAVY RAINFALL POSSIBLE ON FRIDAY. A COLD FRONT
WILL MOVE THROUGH THE REGION DURING THE DAY ON FRIDAY. DRIER AIR
WORKING INTO THE REGION FRIDAY NIGHT AFTER THE COLD FRONTAL
PASSAGE. EXPECTING SHOWER AND THUNDERSTORM ACTIVITY TO DIMINISH
EARLY FRIDAY EVENING.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 341 PM EDT WEDNESDAY...THE EXTENDED PORTION OF THE FORECAST
WILL FEATURE PRETTY QUIET AND COOL WEATHER...NO SIGNIFICANT
CHANCES FOR PRECIPITATION. UPPER LEVEL LOW LIFTS NORTHEAST AND
AWAY FROM THE NORTH COUNTRY SATURDAY AND A RIDGE OF SURFACE HIGH
PRESSURE BUILDS INTO THE AREA. MAINLY DRY WEATHER IS EXPECTED
FROM SATURDAY THROUGH MONDAY. A LOW PRESSURE SYSTEM PASSING NORTH
OF OUR REGION ON MONDAY NIGHT WILL BRING A CHANCE FOR SOME
SHOWERS...THOUGH BEST DYNAMICS REMAIN WELL NORTH OF OUR FORECAST
AREA. TUESDAY THROUGH WEDNESDAY WILL ALSO BE QUIET WITH ANOTHER
RIDGE OF HIGH PRESSURE BUILDING INTO THE AREA.
&&
.AVIATION /04Z THURSDAY THROUGH MONDAY/...
THROUGH 00Z FRIDAY...DIFFICULT AVIATION FORECAST OVER THE NEXT 24
HOURS AS MOST MODELS NOT HANDLING THE CURRENT CONDITIONS VERY
WELL. BROKEN LINE OF SHOWERS/STORMS ENTERING THE OTTAWA RIVER
VALLEY ASSOCIATED WITH A PRE-FRONTAL SURFACE TROUGH WILL SHIFT
EAST INTO THE NORTH COUNTRY OVERNIGHT WHILE DISSIPATING. HAVE PUT
IN SOME VCTS FOR KMSS/KSLK BUT ONLY VCSH EASTWARD AS INSTABILITY
WEAKENS BY THE TIME PRECIP GETS THERE. SCATTERED SHOWERS PERSIST
THROUGH 09-12Z ALONG WITH SOME MVFR CIGS...THEN DISSIPATE FOR THE
MORNING HOURS AS THE REAL COLD FRONT BEGINS TO MOVE INTO THE SAINT
LAWRENCE VALLEY. MAINLY VFR CONDITIONS ARE THEN EXPECTED THURSDAY
WITH SCATTERED SHOWERS AND POSSIBLY STORMS ARE LIKELY AGAIN FROM
THE CHAMPLAIN VALLEY EAST DURING THE AFTERNOON...THOUGH DIFFICULT
TO FORECAST TIMING AND LOCATION SO HAVE JUST GONE WITH SOME MORE
VCSH. WINDS REMAIN MODERATE AT 5-10 KNOTS THROUGH THE PERIOD...
GUSTING A BIT THIS EVENING AND AGAIN TOMORROW AFTERNOON.
OUTLOOK 00Z FRIDAY THROUGH MONDAY...
00Z FRIDAY THROUGH 00Z SATURDAY...VFR WITH OCCASIONAL MVFR/IFR IN
SHOWERS/THUNDERSTORMS AS A WARM/OCCLUDED FRONT LIFTS ACROSS THE
AREA.
00Z SATURDAY THROUGH MONDAY...MAINLY VFR UNDER SURFACE HIGH PRESSURE.
&&
.MARINE...
A LAKE WIND ADVISORY IS IN EFFECT THROUGH EARLY THURSDAY MORNING. SOUTH
WINDS WILL INCREASE THIS EVENING TO 15 TO 25 KNOTS...PEAKING
AROUND MIDNIGHT WITH SOME GUSTS UP TO 30 KNOTS..ESPECIALLY ACROSS
THE OPEN WATERS OF CENTRAL AND NORTHERN LAKE CHAMPLAIN. WINDS
WILL GRADUALLY DECREASE TOWARDS THURSDAY MORNING WITH SOUTH WINDS
FROM 10 TO 20 KNOTS EXPECTED ON THURSDAY. THESE WINDS WILL CREATE
WAVES OF 2 TO 4 FEET ON THE BROAD LAKE...ESPECIALLY ACROSS THE
CENTRAL AND NORTHERN PORTIONS. WAVE HEIGHTS WILL DECREASE TO 1 TO
3 FEET FOR THURSDAY. IN ADDITION...SCATTERED SHOWERS AND POSSIBLE
THUNDERSTORMS MAY AFFECT THE AREA TONIGHT THROUGH THURSDAY...WITH
MORE WIDESPREAD SHOWERS AND THUNDERSTORMS LIKELY LATE THURSDAY
NIGHT AND INTO FRIDAY.
&&
.EQUIPMENT...
AS OF 456 PM EDT WEDNESDAY...THE KTYX 88D DOPPLER RADAR IN
NORTHERN NEW YORK HAS BEEN RESTORED TO SERVICE. SOME ADDITIONAL
WORK ON THIS RADAR WILL NEED TO BE DONE ON THURSDAY.
AS OF 350 AM EDT WEDNESDAY...NOAA WEATHER RADIO STATION WXM 44...
BROADCASTING FROM THE TOP OF MOUNT ASCUTNEY VERMONT...REMAINS OFF
THE AIR UNTIL FURTHER NOTICE DUE TO A DAMAGED ANTENNA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...WGH
NEAR TERM...JMG/LOCONTO
SHORT TERM...WGH
LONG TERM...NEILES
AVIATION...LAHIFF
MARINE...MUCCILLI
EQUIPMENT...BTV
AREA FORECAST DISCUSSION
NWS RALEIGH NC
321 PM EDT THU AUG 8 2013
.SYNOPSIS...
AN AREA OF HIGH PRESSURE ANCHORED OFFSHORE WILL RESULT IN A MOIST
SOUTHERLY FLOW ACROSS THE CAROLINAS THROUGH FRIDAY. A WEAK COLD
FRONT WILL APPROACH THE REGION FROM THE NORTH OVER THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 200 PM THURSDAY...
A WEAK WEST-EAST OR WSW-ENE ORIENTED UPPER LEVEL RIDGE ACROSS THE
SOUTH-CENTRAL AND SOUTHEAST CONUS WILL REMAIN IN PLACE THROUGH
TONIGHT...WITH THE PRIMARY BELT OF WESTERLIES LOCATED ACROSS THE
NORTHERN TIER OF THE CONUS (I.E. GREAT LAKES). WEAK WSW FLOW ALOFT
WILL PREVAIL ACROSS THE CAROLINAS. SOUTHERLY LOW-LEVEL RETURN FLOW
WILL PERSIST ACROSS THE REGION...ON THE WESTERN PERIPHERY OF A BROAD
SFC-H85 RIDGE CENTERED OFFSHORE IN THE ATLANTIC. LOW-LEVEL FLOW IS
PROGGED TO STRENGTHEN FROM 5-10 KT EARLY THIS AFTERNOON TO 15-25 KT
TONIGHT AS A POTENT UPPER LEVEL LOW IN ONTARIO PROGRESSES EAST
TOWARD QUEBEC AND AN ATTENDANT LOW-LEVEL TROUGH PROGRESSES INTO THE
OH VALLEY AND MID-ATLANTIC.
THIS AFTERNOON THROUGH MIDNIGHT:
ISOLD SHOWERS DEVELOPED IN THE FOOTHILLS AND FAR WESTERN PIEDMONT
THIS MORNING AND HAVE PERSISTED THROUGH EARLY THIS AFTERNOON. THIS
ACTIVITY IS ASSOCIATED WITH WEAK H85 CONFLUENCE IN THE PRESENCE OF
MARGINAL DIURNAL DESTABILIZATION AND DEEP MOISTURE (PWAT ~2.00").
THIS ACTIVITY MAY ALSO BE AIDED BY A VERY SUBTLE SMALL AMPLITUDE
DISTURBANCE EMBEDDED WITHIN WEAK WSW FLOW ALOFT OVER UPSTATE SC AND
SOUTHWEST NC. RAP GUIDANCE SUGGESTS THAT THE ZONE OF WEAK H85
CONFLUENCE ACTING AS A FOCUS WILL SHIFT EAST OF THE I-77 CORRIDOR
INTO THE FAR WESTERN PIEDMONT LATE THIS AFT/EVE...AND PROBABILITIES
FOR ISOLD TO SCT SHOWER ACTIVITY SHOULD ACCORDINGLY INCREASE
(40-50%) IN THE TRIAD AND W/SW PIEDMONT. ACTIVITY SHOULD PEAK IN
COVERAGE/INTENSITY BETWEEN 20-00Z WHEN DIURNAL DESTABILIZATION WILL
BE MAXIMIZED WITH MLCAPE VALUES OF 500-1000 J/KG...FOLLOWED BY
DECREASING COVERAGE/ INTENSITY THEREAFTER IN ASSOC/W THE ONSET OF
NOCTURNAL STABILIZATION. AN ISOLD THUNDERSTORM CANNOT BE RULED
OUT...THOUGH MARGINAL MLCAPE...WEAK MID-LEVEL LAPSE RATES AND WEAK
OVERALL FORCING MAY ULTIMATELY SERVE AS A LIMITING FACTOR W/REGARD
TO LIGHTNING. ALONG AND EAST OF THE HWY 1 CORRIDOR...STRONGER
INSOLATION WILL RESULT IN BETTER INSTABILITY WITH MLCAPE VALUES OF
1000-1500 J/KG EXPECTED. ALTHOUGH A WHOLESALE LACK OF FORCING MAY
LARGELY PRECLUDE CONVECTIVE DEVELOPMENT ALONG/EAST OF HWY 1...DEEP
MOISTURE...SEASONABLE DIURNAL DESTABILIZATION AND LITTLE OR NO CIN
SHOULD AT LEAST ALLOW FOR VERY ISOLD DEVELOPMENT...AND WILL INDICATE
A SLIGHT CHANCE (20%) OF SHOWERS IN THAT AREA PRIOR TO SUNSET.
OUTSIDE OF SOUTHERN SAMPSON COUNTY...ANTICIPATE LITTLE INFLUENCE
FROM THE SEABREEZE GIVEN LOW-LEVEL FLOW BECOMING INCREASINGLY
PARALLEL TO THE COAST THIS AFT/EVE. EXPECT HIGHS TODAY RANGING FROM
87-91F ALONG/EAST OF HWY 1 TO 82-85F IN THE WESTERN PIEDMONT WHERE
MORE CLOUD COVER IS PRESENT AND ISOLD SHOWER ACTIVITY MORE LIKELY.
MIDNIGHT THROUGH SUNRISE FRI:
FORCING FOR ASCENT WILL LARGELY BE ABSENT OVERNIGHT GIVEN WEAK FLOW
ALOFT...UNIDIRECTIONAL (SW) LOW-LEVEL FLOW AND LITTLE OR NO WARM
ADVECTION. A FEW ISOLD SHOWERS OR SPRINKLES CANNOT BE RULED OUT
GIVEN SUCH DEEP MOISTURE (PWAT ~2.00")...MARGINAL MUCAPE ASSOC/W A
925 MB AIRMASS CHARACTERIZED BY A T/TD OF 22/19C AND A SMALL
POTENTIAL FOR SUBTLE DISTURBANCES ALOFT OR WEAK LOW-LEVEL
CONVERGENCE...PRIMARILY IN THE W/NW PIEDMONT. WILL INDICATE A SLIGHT
CHANCE OF SHOWERS IN THE TRIAD AND FAR WESTERN PIEDMONT. EXPECT
RELATIVELY WARM LOWS IN THE LOWER 70S. -VINCENT
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
AS OF 315 PM THURSDAY...
WEAK RIDGING ALOFT WILL PERSIST ACROSS THE SOUTH-CENTRAL AND
SOUTHEAST CONUS FRI/FRI NIGHT...WITH THE PRIMARY BELT OF WESTERLIES
CONFINED TO THE FAR NORTHERN MID-ATLANTIC...GREAT LAKES...AND NEW
ENGLAND. DEEP MOISTURE WILL PERSIST OVER THE CAROLINAS WITH PWAT
VALUES IN VICINITY OF 2.00"...AND DIURNAL DESTABILIZATION WILL BE
SOMEWHAT TEMPERED BY THE EXPECTATION OF OCCASIONALLY BROKEN CLOUD
COVER AND VERY WEAK (NEAR MOIST-ADIABATIC) MID-LEVEL LAPSE RATES...
WITH MLCAPE VALUES GENERALLY 750-1500 J/KG...THOUGH 1500-2000 J/KG
WILL BE POSSIBLE IF INSOLATION REMAINS UNINHIBITED IN SOME AREAS.
LITTLE IF ANY DIRECT UPPER LEVEL FORCING WILL BE PRESENT OVER
CENTRAL NC ON FRI/FRI NIGHT GIVEN THAT THE REGION IS AT THE FAR
SOUTHERN FRINGE OF THE WESTERLIES. HOWEVER...AN UPPER LEVEL LOW OVER
ONTARIO THIS AFTERNOON WILL TRACK EAST INTO QUEBEC TONIGHT/FRI...AND
AN ATTENDANT LOW-LEVEL TROUGH /SFC COLD FRONT/ WILL PUSH EAST FROM
THE GREAT LAKES INTO NEW ENGLAND AND THE NORTHERN MID-ATLANTIC. AN
EXTENSION OF THIS LOW-LEVEL TROUGH IS EXPECTED TO STRETCH SOUTHWEST
INTO WEST/NW PORTIONS OF THE CAROLINAS LATE FRIDAY AFT/EVE AND
FRIDAY NIGHT...AND THIS WILL LIKELY SERVE AS AN EFFECTIVE FOCUS FOR
CONVECTIVE DEVELOPMENT GIVEN EXCELLENT DEEP-LAYER MOISTURE...
MODERATE INSTABILITY AROUND/SHORTLY AFTER PEAK HEATING AND AT LEAST
MARGINAL INSTABILITY PERSISTING OVERNIGHT. ANTICIPATE THAT THE
SEABREEZE WILL REMAIN PINNED SOUTHEAST OF CUMBERLAND/SAMPSON/WAYNE
COUNTIES FRIDAY AFT/EVE GIVEN 15-20 KT SW/WSW LOW-LEVEL FLOW THAT
WILL BE NEAR PARALLEL TO THE NC COAST...ESPECIALLY GIVEN HIGHS AT
LEAST SOMEWHAT TEMPERED BY CLOUD COVER AND A RESULTING WEAKER
LAND/WATER TEMPERATURE GRADIENT. WITH THE ABOVE IN MIND...WILL
INDICATE PRECIP CHANCES RANGING FROM 40-60% WEST OF HWY 1 FRIDAY
AFTERNOON THROUGH MIDNIGHT...AND SLIGHT TO LOW CHANCE (20-40%) EAST
OF HWY 1...LOWEST EAST OF I-95 AND SOUTH OF HWY 64. WILL INDICATE A
SLIGHT TO LOW CHANCE (20-30%) OF CONVECTION PERSISTING OVERNIGHT
GIVEN CONTINUED (ALBEIT WEAK) LOW-LEVEL CONVERGENCE...DEEP
MOISTURE...AND MARGINAL INSTABILITY...PRIMARILY ALONG AND NORTH OF
HWY 64 AS THE LOW-LEVEL TROUGH BECOMES INCREASINGLY WEST-EAST
ORIENTED AND APPROACHES THE NC/VA BORDER FROM THE NORTH. HIGHS
FRIDAY RANGING FROM THE MID/UPPER 80S TO LOWER 90S...DEPENDENT
PRIMARILY ON CLOUD COVER. LOWS FRI NIGHT LOWER/MID 70S. -VINCENT
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
AS OF 230 PM THURSDAY...
THIS WEEKEND...SURFACE HIGH OFFSHORE FLATTENS AND ALIGNS MORE
EAST-WEST ACROSS THE SOUTHERN GULF STATES. ENSUING WESTERLY FLOW
WILL SHARPEN LEE TROUGHING OVER CENTRAL NC...INTO WHICH A WEAK COLD
FRONT SAGGING SOUTH OUT OF THE OHIO VALLEY WILL MERGE SATURDAY
NIGHT. MEANWHILE...FLOW WILL REMAIN WEAK AND NEAR ZONAL ALOFT. LOW
LEVEL FORCING FROM THE TWO BOUNDARIES WILL BE SUFFICIENT FOR
DEVELOPMENT OF FAIRLY WIDESPREAD CONVECTION IN THE LATE DAY AS HIGHS
WILL BE WITHIN A COUPLE OF DEGREES EITHER SIDE OF 90. EXPECT THE
FRONT DROPPING SOUTH TO BE THE STRONGER OF THE TWO AND WILL HAVE
LIKELY POPS ACROSS THE NORTH TO CHANCE IN THE SOUTH.
WE WILL HAVE A CONTINUING CHANCE OF SHOWERS OVERNIGHT SATURDAY NIGHT
AS THE BOUNDARIES MERGE...WHILE SUNDAY SHOULD BE QUITE ACTIVE
CONVECTIVELY...50 POP NORTHWEST TO 70 SOUTHEAST...ESPECIALLY ACROSS
THE SOUTHERN TIER WHERE MODELS HINT THAT WE COULD SEE A WEAK SURFACE
WAVE DEVELOP ALONG THE FRONT. NOT SEEING MUCH COOL AIR ADVECTION OR
HEIGHT FALLS SUNDAY...BUT HEAVY CLOUDINESS AND PRECIP WILL HAMPER
THE DIURNAL CLIMB...WITH HIGHS IN THE MID AND UPPER 80S. -MLM
ON MONDAY MOSTLY ZONAL FLOW OVER THE EASTERN US WILL YIELD TO A
TROUGH DIGGING SOUTHWARD FROM NORTHERN ONTARIO. THIS TROUGH WILL
DOMINATE THE SENSIBLE WEATHER THROUGH MIDWEEK...WITH LOWER THAN
NORMAL HIGH TEMPERATURES AND AN ABOVE NORMAL CHANCE OF RAIN.
AN INITIAL STATIONARY SURFACE FRONT OVER CENTRAL NC ON MONDAY WILL
BE PUSHED TO THE SE BY A SECOND APPROACHING SURFACE FRONT ASSOCIATED
WITH THE DIGGING TROUGH AROUND TUESDAY NIGHT. BOTH GFS AND EURO
MODELS SHOW THIS GREAT LAKES TROUGH AXIS AMPLIFYING SOUTHWARD INTO
KY AND TN BY EARLY TUESDAY. THESE MODELS HAVE SOME DISAGREEMENT IN
HOW QUICKLY THIS TROUGH MIGRATES EASTWARD. THE EASTWARD TROUGH
MOVEMENT WILL DETERMINE WHEN AND WHERE THIS SECOND SURFACE FRONT
WILL SET UP OVER CENTRAL NC. BOTH THE EURO AND GFS PREDICT THIS
FRONT TO BECOME ZONALLY ORIENTED...THE GFS EXPECTS THE FRONT TO
STALL OUT AND REMAIN STATIONARY OVER CENTRAL NC THROUGH WEDNESDAY
AND THURSDAY AS SURFACE HIGH PRESSURE BUILDS TO THE NORTH...WHILE
THE EURO HAS THE FRONT SLOWLY PASS THROUGH CENTRAL NC THROUGH
TUESDAY AND TUESDAY NIGHT BEFORE STALLING OUT MUCH FARTHER TO THE
SOUTH ON THURSDAY MORNING. THE LOCATION OF THIS FRONT WILL HIGHLY
IMPACT WHERE THE GREATEST PRECIP CHANCES WILL BE...WHILE THE SURFACE
HIGH AND ASSOCIATED DRY AIR WILL PUSH HIGH TEMPERATURES TO BE LOWER
INTO THE MIDWEEK.
THEREFORE...WILL PREDICT AN ABOVE NORMAL CHANCE OF POPS ACROSS THE
FORECAST AREA FOR MONDAY AND TUESDAY ASSOCIATED WITH THE INITIAL
FRONT...FOR WEDNESDAY AND THURSDAY...WITH MODEL AGREEMENT THAT THE
SECOND FRONT WILL BE OVER CENTRAL NC...HIGHER POPS TO THE SE AS
DRIER AIR IS EXPECTED TO BUILD BEHIND THE FRONT TO THE FAR NW OF THE
FORECAST AREA. HIGHS UPPER 80S-LOW 90S FOR MONDAY, COOLING TO THE
MID 80S FOR TUESDAY AND WEDNESDAY BEFORE MAINLY LOWER 80S ON
THURSDAY. LOWS NEAR PERSISTENCE ON MONDAY NIGHT...UPPER 60S AND LOW
70S...DECREASING TO THE MID AND UPPER 60S FOR TUESDAY AND WEDNESDAY
NIGHT. -BAS
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 200 PM THURSDAY...
24-HR TAF PERIOD:
VFR CONDITIONS WILL LARGELY PREVAIL THIS AFTERNOON THROUGH 06Z
TONIGHT. THE EXCEPTION WILL BE AT THE INT/GSO TERMINALS WHERE
PERIODIC MVFR CEILINGS AND PERHAPS ISOLD SHOWER ACTIVITY WILL BE
POSSIBLE THROUGH 00-03Z THIS EVENING. OVERNIGHT...MVFR/IFR CEILINGS
WILL BE POSSIBLE AT ALL TERMINALS...THOUGH CONFIDENCE IS RELATIVELY
LOW W/REGARD TO THE TIMING AND COVERAGE OF SUB-VFR CEILINGS ASSOC/W
WITH POTENTIAL STRATUS DEVELOPMENT IN THE 08-14Z TIME FRAME.
MVFR/IFR VISBYS IN FOG WILL ALSO BE POSSIBLE BETWEEN 08-12Z AT THE
FAY/RWI TERMINALS (SIMILAR TO PREVIOUS NIGHTS)...THOUGH THIS WILL
DEPEND ON CLOUD COVER. A BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS
IS EXPECTED FRIDAY AFTERNOON AS A LOW-LEVEL TROUGH DEVELOPS IN THE
LEE OF THE APPALACHIANS.
LOOKING AHEAD:
EXPECT AN ABOVE AVERAGE CHANCE FOR SHOWERS AND THUNDERSTORMS
(PRIMARILY AFTERNOON AND EVENING HOURS) SATURDAY THROUGH EARLY TO
MID NEXT WEEK AS A FRONT APPROACHES FROM THE NORTH AND THEN STALLS
OVER THE CAROLINAS/VA IN THE PRESENCE OF CYCLONIC FLOW ALOFT.
MORNING FOG OR STRATUS WILL ALSO BE POSSIBLE EACH DAY... PRIMARILY
IN THE 08-14Z TIME FRAME. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM..VINCENT
LONG TERM...MLM/BAS
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
226 PM EDT THU AUG 8 2013
.SYNOPSIS...
AN AREA OF HIGH PRESSURE ANCHORED OFFSHORE WILL RESULT IN A MOIST
SOUTHERLY FLOW ACROSS THE CAROLINAS THROUGH FRIDAY. A WEAK COLD
FRONT WILL APPROACH THE REGION FROM THE NORTH OVER THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 200 PM THURSDAY...
A WEAK WEST-EAST OR WSW-ENE ORIENTED UPPER LEVEL RIDGE ACROSS THE
SOUTH-CENTRAL AND SOUTHEAST CONUS WILL REMAIN IN PLACE THROUGH
TONIGHT...WITH THE PRIMARY BELT OF WESTERLIES LOCATED ACROSS THE
NORTHERN TIER OF THE CONUS (I.E. GREAT LAKES). WEAK WSW FLOW ALOFT
WILL PREVAIL ACROSS THE CAROLINAS. SOUTHERLY LOW-LEVEL RETURN FLOW
WILL PERSIST ACROSS THE REGION...ON THE WESTERN PERIPHERY OF A BROAD
SFC-H85 RIDGE CENTERED OFFSHORE IN THE ATLANTIC. LOW-LEVEL FLOW IS
PROGGED TO STRENGTHEN FROM 5-10 KT EARLY THIS AFTERNOON TO 15-25 KT
TONIGHT AS A POTENT UPPER LEVEL LOW IN ONTARIO PROGRESSES EAST
TOWARD QUEBEC AND AN ATTENDANT LOW-LEVEL TROUGH PROGRESSES INTO THE
OH VALLEY AND MID-ATLANTIC.
THIS AFTERNOON THROUGH MIDNIGHT:
ISOLD SHOWERS DEVELOPED IN THE FOOTHILLS AND FAR WESTERN PIEDMONT
THIS MORNING AND HAVE PERSISTED THROUGH EARLY THIS AFTERNOON. THIS
ACTIVITY IS ASSOCIATED WITH WEAK H85 CONFLUENCE IN THE PRESENCE OF
MARGINAL DIURNAL DESTABILIZATION AND DEEP MOISTURE (PWAT ~2.00").
THIS ACTIVITY MAY ALSO BE AIDED BY A VERY SUBTLE SMALL AMPLITUDE
DISTURBANCE EMBEDDED WITHIN WEAK WSW FLOW ALOFT OVER UPSTATE SC AND
SOUTHWEST NC. RAP GUIDANCE SUGGESTS THAT THE ZONE OF WEAK H85
CONFLUENCE ACTING AS A FOCUS WILL SHIFT EAST OF THE I-77 CORRIDOR
INTO THE FAR WESTERN PIEDMONT LATE THIS AFT/EVE...AND PROBABILITIES
FOR ISOLD TO SCT SHOWER ACTIVITY SHOULD ACCORDINGLY INCREASE
(40-50%) IN THE TRIAD AND W/SW PIEDMONT. ACTIVITY SHOULD PEAK IN
COVERAGE/INTENSITY BETWEEN 20-00Z WHEN DIURNAL DESTABILIZATION WILL
BE MAXIMIZED WITH MLCAPE VALUES OF 500-1000 J/KG...FOLLOWED BY
DECREASING COVERAGE/ INTENSITY THEREAFTER IN ASSOC/W THE ONSET OF
NOCTURNAL STABILIZATION. AN ISOLD THUNDERSTORM CANNOT BE RULED
OUT...THOUGH MARGINAL MLCAPE...WEAK MID-LEVEL LAPSE RATES AND WEAK
OVERALL FORCING MAY ULTIMATELY SERVE AS A LIMITING FACTOR W/REGARD
TO LIGHTNING. ALONG AND EAST OF THE HWY 1 CORRIDOR...STRONGER
INSOLATION WILL RESULT IN BETTER INSTABILITY WITH MLCAPE VALUES OF
1000-1500 J/KG EXPECTED. ALTHOUGH A WHOLESALE LACK OF FORCING MAY
LARGELY PRECLUDE CONVECTIVE DEVELOPMENT ALONG/EAST OF HWY 1...DEEP
MOISTURE...SEASONABLE DIURNAL DESTABILIZATION AND LITTLE OR NO CIN
SHOULD AT LEAST ALLOW FOR VERY ISOLD DEVELOPMENT...AND WILL INDICATE
A SLIGHT CHANCE (20%) OF SHOWERS IN THAT AREA PRIOR TO SUNSET.
OUTSIDE OF SOUTHERN SAMPSON COUNTY...ANTICIPATE LITTLE INFLUENCE
FROM THE SEABREEZE GIVEN LOW-LEVEL FLOW BECOMING INCREASINGLY
PARALLEL TO THE COAST THIS AFT/EVE. EXPECT HIGHS TODAY RANGING FROM
87-91F ALONG/EAST OF HWY 1 TO 82-85F IN THE WESTERN PIEDMONT WHERE
MORE CLOUD COVER IS PRESENT AND ISOLD SHOWER ACTIVITY MORE LIKELY.
MIDNIGHT THROUGH SUNRISE FRI:
FORCING FOR ASCENT WILL LARGELY BE ABSENT OVERNIGHT GIVEN WEAK FLOW
ALOFT...UNIDIRECTIONAL (SW) LOW-LEVEL FLOW AND LITTLE OR NO WARM
ADVECTION. A FEW ISOLD SHOWERS OR SPRINKLES CANNOT BE RULED OUT
GIVEN SUCH DEEP MOISTURE (PWAT ~2.00")...MARGINAL MUCAPE ASSOC/W A
925 MB AIRMASS CHARACTERIZED BY A T/TD OF 22/19C AND A SMALL
POTENTIAL FOR SUBTLE DISTURBANCES ALOFT OR WEAK LOW-LEVEL
CONVERGENCE...PRIMARILY IN THE W/NW PIEDMONT. WILL INDICATE A SLIGHT
CHANCE OF SHOWERS IN THE TRIAD AND FAR WESTERN PIEDMONT. EXPECT
RELATIVELY WARM LOWS IN THE LOWER 70S. -VINCENT
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
AS OF 250 AM THURSDAY...
FRIDAY/FRIDAY NIGHT...
THE COLD FRONT OVER THE MIDWEST WILL MOVE VERY SLOWLY INTO THE OHIO
VALLEY REGION BY FRIDAY AS IT RUNS INTO A MODEST RIDGE OVER THE
SOUTHEAST US. AHEAD OF THE FRONT...LOW-LEVEL TRAJECTORIES WILL
BECOME MORE SOUTHWESTERLY WITH SIGNS OF A PREFRONTAL/LEE TROUGH
BEGINNING TO DEVELOP. PW WILL BE QUITE HIGH (ABOVE 2 INCHES) AND
INSTABILITY SLIGHTLY HIGHER THAN THE PAST COUPLE OF DAYS (AROUND
1000 J/KG). THUS...CHANCE POPS WILL BE INCLUDED ACROSS THE ENTIRE
CWA...THOUGH COVERAGE IS LIKELY TO BE GREATEST IN THE WEST. DEEP
SHEAR WILL CONTINUE T BE WEAK...SO THE MAIN THREAT WILL BE HEAVY
RAINS FROM SLOW MOVING STORMS. HIGHS RIGHT AROUND NORMAL...87-91. A
FEW SHOWERS AND STORMS MAY BE POSSIBLE ACROSS THE NORTH FRIDAY NIGHT
AS THE 850MB TROUGH DROPS SOUTH INTO VIRGINIA. LOWS IN THE LOWER
70S. -SMITH
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
AS OF 230 PM THURSDAY...
THIS WEEKEND...SURFACE HIGH OFFSHORE FLATTENS AND ALIGNS MORE
EAST-WEST ACROSS THE SOUTHERN GULF STATES. ENSUING WESTERLY FLOW
WILL SHARPEN LEE TROUGHING OVER CENTRAL NC...INTO WHICH A WEAK COLD
FRONT SAGGING SOUTH OUT OF THE OHIO VALLEY WILL MERGE SATURDAY
NIGHT. MEANWHILE...FLOW WILL REMAIN WEAK AND NEAR ZONAL ALOFT. LOW
LEVEL FORCING FROM THE TWO BOUNDARIES WILL BE SUFFICIENT FOR
DEVELOPMENT OF FAIRLY WIDESPREAD CONVECTION IN THE LATE DAY AS HIGHS
WILL BE WITHIN A COUPLE OF DEGREES EITHER SIDE OF 90. EXPECT THE
FRONT DROPPING SOUTH TO BE THE STRONGER OF THE TWO AND WILL HAVE
LIKELY POPS ACROSS THE NORTH TO CHANCE IN THE SOUTH.
WE WILL HAVE A CONTINUING CHANCE OF SHOWERS OVERNIGHT SATURDAY NIGHT
AS THE BOUNDARIES MERGE...WHILE SUNDAY SHOULD BE QUITE ACTIVE
CONVECTIVELY...50 POP NORTHWEST TO 70 SOUTHEAST...ESPECIALLY ACROSS
THE SOUTHERN TIER WHERE MODELS HINT THAT WE COULD SEE A WEAK SURFACE
WAVE DEVELOP ALONG THE FRONT. NOT SEEING MUCH COOL AIR ADVECTION OR
HEIGHT FALLS SUNDAY...BUT HEAVY CLOUDINESS AND PRECIP WILL HAMPER
THE DIURNAL CLIMB...WITH HIGHS IN THE MID AND UPPER 80S. -MLM
ON MONDAY MOSTLY ZONAL FLOW OVER THE EASTERN US WILL YIELD TO A
TROUGH DIGGING SOUTHWARD FROM NORTHERN ONTARIO. THIS TROUGH WILL
DOMINATE THE SENSIBLE WEATHER THROUGH MIDWEEK...WITH LOWER THAN
NORMAL HIGH TEMPERATURES AND AN ABOVE NORMAL CHANCE OF RAIN.
AN INITIAL STATIONARY SURFACE FRONT OVER CENTRAL NC ON MONDAY WILL
BE PUSHED TO THE SE BY A SECOND APPROACHING SURFACE FRONT ASSOCIATED
WITH THE DIGGING TROUGH AROUND TUESDAY NIGHT. BOTH GFS AND EURO
MODELS SHOW THIS GREAT LAKES TROUGH AXIS AMPLIFYING SOUTHWARD INTO
KY AND TN BY EARLY TUESDAY. THESE MODELS HAVE SOME DISAGREEMENT IN
HOW QUICKLY THIS TROUGH MIGRATES EASTWARD. THE EASTWARD TROUGH
MOVEMENT WILL DETERMINE WHEN AND WHERE THIS SECOND SURFACE FRONT
WILL SET UP OVER CENTRAL NC. BOTH THE EURO AND GFS PREDICT THIS
FRONT TO BECOME ZONALLY ORIENTED...THE GFS EXPECTS THE FRONT TO
STALL OUT AND REMAIN STATIONARY OVER CENTRAL NC THROUGH WEDNESDAY
AND THURSDAY AS SURFACE HIGH PRESSURE BUILDS TO THE NORTH...WHILE
THE EURO HAS THE FRONT SLOWLY PASS THROUGH CENTRAL NC THROUGH
TUESDAY AND TUESDAY NIGHT BEFORE STALLING OUT MUCH FARTHER TO THE
SOUTH ON THURSDAY MORNING. THE LOCATION OF THIS FRONT WILL HIGHLY
IMPACT WHERE THE GREATEST PRECIP CHANCES WILL BE...WHILE THE SURFACE
HIGH AND ASSOCIATED DRY AIR WILL PUSH HIGH TEMPERATURES TO BE LOWER
INTO THE MIDWEEK.
THEREFORE...WILL PREDICT AN ABOVE NORMAL CHANCE OF POPS ACROSS THE
FORECAST AREA FOR MONDAY AND TUESDAY ASSOCIATED WITH THE INITIAL
FRONT...FOR WEDNESDAY AND THURSDAY...WITH MODEL AGREEMENT THAT THE
SECOND FRONT WILL BE OVER CENTRAL NC...HIGHER POPS TO THE SE AS
DRIER AIR IS EXPECTED TO BUILD BEHIND THE FRONT TO THE FAR NW OF THE
FORECAST AREA. HIGHS UPPER 80S-LOW 90S FOR MONDAY, COOLING TO THE
MID 80S FOR TUESDAY AND WEDNESDAY BEFORE MAINLY LOWER 80S ON
THURSDAY. LOWS NEAR PERSISTENCE ON MONDAY NIGHT...UPPER 60S AND LOW
70S...DECREASING TO THE MID AND UPPER 60S FOR TUESDAY AND WEDNESDAY
NIGHT. -BAS
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 200 PM THURSDAY...
24-HR TAF PERIOD:
VFR CONDITIONS WILL LARGELY PREVAIL THIS AFTERNOON THROUGH 06Z
TONIGHT. THE EXCEPTION WILL BE AT THE INT/GSO TERMINALS WHERE
PERIODIC MVFR CEILINGS AND PERHAPS ISOLD SHOWER ACTIVITY WILL BE
POSSIBLE THROUGH 00-03Z THIS EVENING. OVERNIGHT...MVFR/IFR CEILINGS
WILL BE POSSIBLE AT ALL TERMINALS...THOUGH CONFIDENCE IS RELATIVELY
LOW W/REGARD TO THE TIMING AND COVERAGE OF SUB-VFR CEILINGS ASSOC/W
WITH POTENTIAL STRATUS DEVELOPMENT IN THE 08-14Z TIME FRAME.
MVFR/IFR VISBYS IN FOG WILL ALSO BE POSSIBLE BETWEEN 08-12Z AT THE
FAY/RWI TERMINALS (SIMILAR TO PREVIOUS NIGHTS)...THOUGH THIS WILL
DEPEND ON CLOUD COVER. A BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS
IS EXPECTED FRIDAY AFTERNOON AS A LOW-LEVEL TROUGH DEVELOPS IN THE
LEE OF THE APPALACHIANS.
LOOKING AHEAD:
EXPECT AN ABOVE AVERAGE CHANCE FOR SHOWERS AND THUNDERSTORMS
(PRIMARILY AFTERNOON AND EVENING HOURS) SATURDAY THROUGH EARLY TO
MID NEXT WEEK AS A FRONT APPROACHES FROM THE NORTH AND THEN STALLS
OVER THE CAROLINAS/VA IN THE PRESENCE OF CYCLONIC FLOW ALOFT.
MORNING FOG OR STRATUS WILL ALSO BE POSSIBLE EACH DAY... PRIMARILY
IN THE 08-14Z TIME FRAME. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM..SMITH
LONG TERM...MLM/BAS
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
705 AM EDT THU AUG 8 2013
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO RIDGE INTO THE CAROLINAS FROM THE
EAST OVER THE NEXT SEVERAL DAYS. WARMER AND MORE HUMID AIR WILL MOVE
INTO THE CAROLINAS ON SOUTH WINDS...ACCOMPANIED BY SCATTERED SHOWERS
AND THUNDERSTORMS. A COLD FRONT WILL STALL NEAR OR JUST NORTH OF THE
AREA MONDAY THROUGH WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM THURSDAY...LOW STRATUS DID NOT DEVELOP AT ALL INLAND
THIS MORNING...RATHER UNEXPECTED GIVEN THE VERY GOOD RADIATIONAL
COOLING CONDITIONS WE HAD. OVER THE NEXT 3 HOURS LOOK FOR SCATTERED
SHOWERS TO DEVELOP NEAR CAPE FEAR AND SPREAD NORTH ACROSS
SOUTHEASTERN NORTH CAROLINA. OTHERWISE NO SIGNIFICANT CHANGES HAVE
BEEN MADE TO THE FORECAST. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
AFTER ENJOYING SEVERAL DAYS OF BELOW-NORMAL TEMPERATURES AND
HUMIDITY...THE REALITY OF AUGUST RETURNS TO THE CAROLINAS TODAY. THE
SURFACE RIDGE AXIS THAT HELD OUR SURFACE WINDS EASTERLY OVER THE
PAST SEVERAL DAYS IS GONE. BERMUDA HIGH PRESSURE WILL ESTABLISH A
SOUTH FLOW ACROSS THE AREA TODAY WITH TEMPERATURES RISING TO AROUND
90 INLAND AND UPPER 80S NEAR THE COAST.
WITH NO SUBSIDENCE INVERSIONS TO DEAL WITH TODAY AND SURFACE-BASED
CAPE BUILDING TO AROUND 1000 J/KG...LOOK FOR SCATTERED SHOWERS AND A
FEW T-STORMS TODAY AS WELL. ACTIVITY COULD GET A VERY EARLY START
ALONG THE COAST AND PARTICULARLY IN THE CAPE FEAR REGION WHERE THE
LAST SEVERAL RUNS OF THE HRRR INDICATE SHOWERS MAY DEVELOP AS EARLY
AS SUNRISE NEAR SOUTHPORT AND WILMINGTON. BY LATE MORNING SCATTERED
CONVECTION SHOULD BE LINING UP ALONG THE DEVELOPING SEABREEZE
BOUNDARY...LIFTING SLOWLY INLAND THROUGH THE AFTERNOON HOURS.
FORECAST POPS RANGE FROM 20-40 PERCENT...HIGHEST ACROSS SE NORTH
CAROLINA.
FOR TONIGHT...INLAND CONVECTIVE ACTIVITY SHOULD GRADUALLY DIMINISH
DURING THE EVENING HOURS WITH SKIES BECOMING MOSTLY CLEAR TO PARTLY
CLOUDY. SOME LOW STRATUS MAY DEVELOP VERY LATE TONIGHT INLAND AS
SATURATION OCCURS WITHIN THE BOUNDARY LAYER BUT 1000-FOOT WINDS
REMAIN A LITTLE TOO STRONG FOR FOG. LOWS WILL FALL TO 72-74 INLAND
AND 73-78 NEAR THE COAST. SOME SOUTH-FACING BEACHES COULD SEE LOW
TEMPERATURES STRUGGLE TO DROP BELOW 80 IF THE ONSHORE WIND CONTINUES
THROUGH THE NIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 AM THURSDAY...MID LEVEL RIDGE WILL REMAIN ACROSS THE AREA
AS A WESTERLY PATTERN DEVELOPS AT THE MID LEVELS. HOWEVER THERE WILL
BE INTERVALS OF RICHER THETA-E AIR TRAVERSING THE ZONAL FLOW WHICH
WARRANTS AT LEAST LOW CHANCE POPS THROUGH THE PERIOD. THE NUMEROUS
CLUSTERS OF THUNDERSTORMS WE HAVE SEEN MOVING ACROSS THE TENNESSEE
VALLEY WILL NOW TAKE AIM ON THE CAROLINAS. THE PIEDMONT TROUGH WILL
BE ENHANCED WITH THE WESTERLY FLOW WHICH WILL ASSIST IN THE FORCING
AS WELL. I HAVE MAINTAINED THE CHANCE POPS...MAINLY ON A DIURNAL
BASIS THROUGH THE PERIOD. AS WE GET CLOSER TO THE WEEKEND...THERE
WILL BE TIMES WHEN LIKELY POPS WILL BE WARRANTED BUT THIS WILL BE
BETTER ADDRESSED WITH THE NEAR TERM FORECAST. TEMPERATURE TRENDS
REMAIN RELATIVELY UNCHANGED WITH THE STRONG RIDGE AND DOWNSLOPE
COMPONENT LEADING TO READINGS SLIGHTLY ABOVE CLIMATOLOGY.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 300 AM THURSDAY...MEDIUM RANGE GUIDANCE IS TRENDING TOWARD A
RATHER WET SCENARIO FOR THE EXTENDED PERIOD. ELONGATED MID LEVEL
RIDGE SHIFTS WEST AND TROUGHING DEVELOPS ACROSS THE OHIO VALLEY.
THE TROUGH REMAINS IN PLACE AS DOES THE FRONT ASSOCIATED WITH
IT...WHICH IS POSITIONED RIGHT ACROSS OUR AREA. THIS WILL PROVIDE
A GOOF FOCUSING MECHANISM FOR INTERVALS OF SHOWERS AND
THUNDERSTORMS. HAVE INCREMENTALLY INCREASED POPS TO REPRESENT THIS
TREND. TEMPERATURES FORECAST IS ALREADY SHOWING LOWER THAN USUAL
DIURNAL RANGE WITH THE MOISTURE AND NEEDED NO CHANGES WITH THE
MORNING UPDATE.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AS OF 12Z...HRRR MODEL HAS BEEN PRETTY CONSISTENT IN DEVELOPING
CONVECTION BY LATE MORNING ALONG THE COAST...ASSOCIATED WITH THE
CONVERGING RESULTANT BOUNDARY. ISOLATED/SCATTERED CONVECTION WILL
TAKE A WHILE TO DEVELOP INLAND...DUE TO RELATIVELY HIGH LFC`S. MOST
OF THE CONVECTION WILL END BY 22Z OR SO. THERE IS A CHANCE OF SOME
NEAR IFR TO IFR STRATUS AFTER MIDNIGHT. WILL REEVALUATE THIS SCENARIO
WITH THE NEXT SET OF MODEL RUNS.
EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS
POSSIBLE THURSDAY THROUGH SATURDAY...BECOMING SCATTERED SUNDAY AND
MONDAY. OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM THURSDAY...SEAS HAVE BUILT TO 3 FT ABOUT 6 HOURS FASTER
THAN ANTICIPATED AT THE WRIGHTSVILLE BEACH NEARSHORE BUOY. ASIDE
FROM THIS CHANGE...THE PREVIOUS FORECAST REMAINS IN GOOD SHAPE.
PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
THE SURFACE RIDGE AXIS THAT HAS HELD OUR WIND DIRECTIONS EASTERLY
FOR THE PAST SEVERAL DAYS HAS FINALLY BROKEN DOWN. RATHER THAN
CANADIAN HIGH PRESSURE POKING DOWN FROM THE NORTHEAST...OUR WEATHER
TODAY AND TONIGHT WILL COME UNDER THE INFLUENCE OF BERMUDA HIGH
PRESSURE FROM THE EAST. THIS MEANS WINDS WILL BECOME SOUTHERLY TODAY
AND SOUTH-SOUTHWESTERLY TONIGHT...WITH SPEEDS AVERAGING 10-12 KNOTS.
SEAS ARE CURRENTLY 2-3 FT WITH PERIODS SPLIT BETWEEN A 6 SECOND WIND
WAVE AND A WEAK 9-10 SECOND SOUTHEAST SWELL. SEAS MAY BUILD HALF A
FOOT THROUGH TONIGHT AS SOUTH WINDS FURTHER DEVELOP THE WIND WAVE
COMPONENT.
RADAR CURRENTLY SHOWS ONLY ISOLATED SHOWERS OUT BEYOND 30 MILES FROM
SHORE...BUT MODELS ARE SHOWING WE SHOULD HAVE SCATTERED SHOWERS
DEVELOPING NEARSHORE NEAR AND NORTH OF CAPE FEAR THIS MORNING.
CONVECTIVE ACTIVITY SHOULD LARGELY SHIFT INLAND THIS AFTERNOON AS
THE SEABREEZE CIRCULATION BECOMES BETTER DEVELOPED.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 AM THURSDAY...ELEMENTS REMAIN THE SAME FOR THE COASTAL
WATERS THROUGH THE PERIOD AS BERMUDA HIGH PRESSURE AND THE PIEDMONT
TROUGH KEEP A SOUTHWESTERLY FLOW IN PLACE. SPEEDS REMAIN STABLE IN A
RANGE OF 10-15 KNOTS...WHICH IF ANYTHING MAY BE ON THE HIGHER END
SATURDAY AFTERNOON AS THE TROUGH STRENGTHENS. THE TEPID INCREASE IN
WINDS ISN/T ENOUGH TO IMPACT SIGNIFICANT SEAS...WHICH REMAIN IN A
2-3 FOOT RANGE.
LONG TERM /SUNDAY THROUGH MONDAY/...
AS OF 300 AM THURSDAY...DIFFUSE FRONT WILL REMAIN JUST INLAND...AT
LEAST LOOKING AT THE LATEST WPC FORECAST AND THIS WILL KEEP A RATHER
WEAK SOUTHWESTERLY FLOW IN PLACE. SPEEDS CONTINUE TO HOVER AROUND
TEN KNOTS OR BELOW. CAN/T RULE OUT BRIEF DISRUPTIONS IN THE SYNOPTIC
FLOW WITH INTERVALS OF CONVECTION EXPECTED BUT THIS OF COURSE IS ALL
BUT IMPOSSIBLE TO FORECAST THIS FAR OUT IN TIME. SIGNIFICANT SEAS
SHOW LITTLE CHANGE AS WELL WITH 2-3 FEET AND LITTLE IN THE WAY OF A
SWELL COMPONENT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TRA
NEAR TERM...TRA
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...43
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
638 AM EDT THU AUG 8 2013
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO RIDGE INTO THE CAROLINAS FROM THE
EAST OVER THE NEXT SEVERAL DAYS. WARMER AND MORE HUMID AIR WILL MOVE
INTO THE CAROLINAS ON SOUTH WINDS...ACCOMPANIED BY SCATTERED SHOWERS
AND THUNDERSTORMS. A COLD FRONT WILL STALL NEAR OR JUST NORTH OF THE
AREA MONDAY THROUGH WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM THURSDAY...LOW STRATUS DID NOT DEVELOP AT ALL INLAND
THIS MORNING...RATHER UNEXPECTED GIVEN THE VERY GOOD RADIATIONAL
COOLING CONDITIONS WE HAD. OVER THE NEXT 3 HOURS LOOK FOR SCATTERED
SHOWERS TO DEVELOP NEAR CAPE FEAR AND SPREAD NORTH ACROSS
SOUTHEASTERN NORTH CAROLINA. OTHERWISE NO SIGNIFICANT CHANGES HAVE
BEEN MADE TO THE FORECAST. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
AFTER ENJOYING SEVERAL DAYS OF BELOW-NORMAL TEMPERATURES AND
HUMIDITY...THE REALITY OF AUGUST RETURNS TO THE CAROLINAS TODAY. THE
SURFACE RIDGE AXIS THAT HELD OUR SURFACE WINDS EASTERLY OVER THE
PAST SEVERAL DAYS IS GONE. BERMUDA HIGH PRESSURE WILL ESTABLISH A
SOUTH FLOW ACROSS THE AREA TODAY WITH TEMPERATURES RISING TO AROUND
90 INLAND AND UPPER 80S NEAR THE COAST.
WITH NO SUBSIDENCE INVERSIONS TO DEAL WITH TODAY AND SURFACE-BASED
CAPE BUILDING TO AROUND 1000 J/KG...LOOK FOR SCATTERED SHOWERS AND A
FEW T-STORMS TODAY AS WELL. ACTIVITY COULD GET A VERY EARLY START
ALONG THE COAST AND PARTICULARLY IN THE CAPE FEAR REGION WHERE THE
LAST SEVERAL RUNS OF THE HRRR INDICATE SHOWERS MAY DEVELOP AS EARLY
AS SUNRISE NEAR SOUTHPORT AND WILMINGTON. BY LATE MORNING SCATTERED
CONVECTION SHOULD BE LINING UP ALONG THE DEVELOPING SEABREEZE
BOUNDARY...LIFTING SLOWLY INLAND THROUGH THE AFTERNOON HOURS.
FORECAST POPS RANGE FROM 20-40 PERCENT...HIGHEST ACROSS SE NORTH
CAROLINA.
FOR TONIGHT...INLAND CONVECTIVE ACTIVITY SHOULD GRADUALLY DIMINISH
DURING THE EVENING HOURS WITH SKIES BECOMING MOSTLY CLEAR TO PARTLY
CLOUDY. SOME LOW STRATUS MAY DEVELOP VERY LATE TONIGHT INLAND AS
SATURATION OCCURS WITHIN THE BOUNDARY LAYER BUT 1000-FOOT WINDS
REMAIN A LITTLE TOO STRONG FOR FOG. LOWS WILL FALL TO 72-74 INLAND
AND 73-78 NEAR THE COAST. SOME SOUTH-FACING BEACHES COULD SEE LOW
TEMPERATURES STRUGGLE TO DROP BELOW 80 IF THE ONSHORE WIND CONTINUES
THROUGH THE NIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 AM THURSDAY...MID LEVEL RIDGE WILL REMAIN ACROSS THE AREA
AS A WESTERLY PATTERN DEVELOPS AT THE MID LEVELS. HOWEVER THERE WILL
BE INTERVALS OF RICHER THETA-E AIR TRAVERSING THE ZONAL FLOW WHICH
WARRANTS AT LEAST LOW CHANCE POPS THROUGH THE PERIOD. THE NUMEROUS
CLUSTERS OF THUNDERSTORMS WE HAVE SEEN MOVING ACROSS THE TENNESSEE
VALLEY WILL NOW TAKE AIM ON THE CAROLINAS. THE PIEDMONT TROUGH WILL
BE ENHANCED WITH THE WESTERLY FLOW WHICH WILL ASSIST IN THE FORCING
AS WELL. I HAVE MAINTAINED THE CHANCE POPS...MAINLY ON A DIURNAL
BASIS THROUGH THE PERIOD. AS WE GET CLOSER TO THE WEEKEND...THERE
WILL BE TIMES WHEN LIKELY POPS WILL BE WARRANTED BUT THIS WILL BE
BETTER ADDRESSED WITH THE NEAR TERM FORECAST. TEMPERATURE TRENDS
REMAIN RELATIVELY UNCHANGED WITH THE STRONG RIDGE AND DOWNSLOPE
COMPONENT LEADING TO READINGS SLIGHTLY ABOVE CLIMATOLOGY.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 300 AM THURSDAY...MEDIUM RANGE GUIDANCE IS TRENDING TOWARD A
RATHER WET SCENARIO FOR THE EXTENDED PERIOD. ELONGATED MID LEVEL
RIDGE SHIFTS WEST AND TROUGHING DEVELOPS ACROSS THE OHIO VALLEY.
THE TROUGH REMAINS IN PLACE AS DOES THE FRONT ASSOCIATED WITH
IT...WHICH IS POSITIONED RIGHT ACROSS OUR AREA. THIS WILL PROVIDE
A GOOF FOCUSING MECHANISM FOR INTERVALS OF SHOWERS AND
THUNDERSTORMS. HAVE INCREMENTALLY INCREASED POPS TO REPRESENT THIS
TREND. TEMPERATURES FORECAST IS ALREADY SHOWING LOWER THAN USUAL
DIURNAL RANGE WITH THE MOISTURE AND NEEDED NO CHANGES WITH THE
MORNING UPDATE.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 06Z...ISOLATED SHRA OVER THE ATLANTIC SHOULD REMAIN JUST EAST
OF THE ILM AIRPORT THROUGH DAYBREAK. ANTICIPATE DEVELOPMENT OF MVFR
CIGS ALONG THE COAST...WITH POSSIBLE IFR/LIFR INLAND DUE TO FOG &
LOW CIGS AN HOUR OR TWO BEFORE DAYBREAK. FLIGHT CATEGORY SHOULD
IMPROVE TO VFR NO LATER THAN 13-14Z. CANNOT RULE OUT ISOLATED
SHOWERS...THUS HAVE OPTED TO INTRODUCE VCSH AT ALL SITES...BEGINNING
ALONG THE COAST FIRST. SHOWERS WILL TAPER OFF IN THE EVENING HOURS.
EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS
POSSIBLE THURSDAY THROUGH SATURDAY...BECOMING SCATTERED SUNDAY AND
MONDAY. OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM THURSDAY...SEAS HAVE BUILT TO 3 FT ABOUT 6 HOURS FASTER
THAN ANTICIPATED AT THE WRIGHTSVILLE BEACH NEARSHORE BUOY. ASIDE
FROM THIS CHANGE...THE PREVIOUS FORECAST REMAINS IN GOOD SHAPE.
PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
THE SURFACE RIDGE AXIS THAT HAS HELD OUR WIND DIRECTIONS EASTERLY
FOR THE PAST SEVERAL DAYS HAS FINALLY BROKEN DOWN. RATHER THAN
CANADIAN HIGH PRESSURE POKING DOWN FROM THE NORTHEAST...OUR WEATHER
TODAY AND TONIGHT WILL COME UNDER THE INFLUENCE OF BERMUDA HIGH
PRESSURE FROM THE EAST. THIS MEANS WINDS WILL BECOME SOUTHERLY TODAY
AND SOUTH-SOUTHWESTERLY TONIGHT...WITH SPEEDS AVERAGING 10-12 KNOTS.
SEAS ARE CURRENTLY 2-3 FT WITH PERIODS SPLIT BETWEEN A 6 SECOND WIND
WAVE AND A WEAK 9-10 SECOND SOUTHEAST SWELL. SEAS MAY BUILD HALF A
FOOT THROUGH TONIGHT AS SOUTH WINDS FURTHER DEVELOP THE WIND WAVE
COMPONENT.
RADAR CURRENTLY SHOWS ONLY ISOLATED SHOWERS OUT BEYOND 30 MILES FROM
SHORE...BUT MODELS ARE SHOWING WE SHOULD HAVE SCATTERED SHOWERS
DEVELOPING NEARSHORE NEAR AND NORTH OF CAPE FEAR THIS MORNING.
CONVECTIVE ACTIVITY SHOULD LARGELY SHIFT INLAND THIS AFTERNOON AS
THE SEABREEZE CIRCULATION BECOMES BETTER DEVELOPED.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 AM THURSDAY...ELEMENTS REMAIN THE SAME FOR THE COASTAL
WATERS THROUGH THE PERIOD AS BERMUDA HIGH PRESSURE AND THE PIEDMONT
TROUGH KEEP A SOUTHWESTERLY FLOW IN PLACE. SPEEDS REMAIN STABLE IN A
RANGE OF 10-15 KNOTS...WHICH IF ANYTHING MAY BE ON THE HIGHER END
SATURDAY AFTERNOON AS THE TROUGH STRENGTHENS. THE TEPID INCREASE IN
WINDS ISN/T ENOUGH TO IMPACT SIGNIFICANT SEAS...WHICH REMAIN IN A
2-3 FOOT RANGE.
LONG TERM /SUNDAY THROUGH MONDAY/...
AS OF 300 AM THURSDAY...DIFFUSE FRONT WILL REMAIN JUST INLAND...AT
LEAST LOOKING AT THE LATEST WPC FORECAST AND THIS WILL KEEP A RATHER
WEAK SOUTHWESTERLY FLOW IN PLACE. SPEEDS CONTINUE TO HOVER AROUND
TEN KNOTS OR BELOW. CAN/T RULE OUT BRIEF DISRUPTIONS IN THE SYNOPTIC
FLOW WITH INTERVALS OF CONVECTION EXPECTED BUT THIS OF COURSE IS ALL
BUT IMPOSSIBLE TO FORECAST THIS FAR OUT IN TIME. SIGNIFICANT SEAS
SHOW LITTLE CHANGE AS WELL WITH 2-3 FEET AND LITTLE IN THE WAY OF A
SWELL COMPONENT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TRA
NEAR TERM...TRA
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...SGL/TRA
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
320 AM EDT THU AUG 8 2013
.SYNOPSIS...
A GRADUAL TRANSITION TO WARMER TEMPERATURES AND INCREASED CHANCES
FOR RAIN WILL OCCUR THROUGH THE WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM THURSDAY...AFTER ENJOYING SEVERAL DAYS OF BELOW-NORMAL
TEMPERATURES AND HUMIDITY...THE REALITY OF AUGUST RETURNS TO THE
CAROLINAS TODAY. THE SURFACE RIDGE AXIS THAT HELD OUR SURFACE WINDS
EASTERLY OVER THE PAST SEVERAL DAYS IS GONE. BERMUDA HIGH PRESSURE
WILL ESTABLISH A SOUTH FLOW ACROSS THE AREA TODAY WITH TEMPERATURES
RISING TO AROUND 90 INLAND AND UPPER 80S NEAR THE COAST.
WITH NO SUBSIDENCE INVERSIONS TO DEAL WITH TODAY AND SURFACE-BASED
CAPE BUILDING TO AROUND 1000 J/KG...LOOK FOR SCATTERED SHOWERS AND A
FEW T-STORMS TODAY AS WELL. ACTIVITY COULD GET A VERY EARLY START
ALONG THE COAST AND PARTICULARLY IN THE CAPE FEAR REGION WHERE THE
LAST SEVERAL RUNS OF THE HRRR INDICATE SHOWERS MAY DEVELOP AS EARLY
AS SUNRISE NEAR SOUTHPORT AND WILMINGTON. BY LATE MORNING SCATTERED
CONVECTION SHOULD BE LINING UP ALONG THE DEVELOPING SEABREEZE
BOUNDARY...LIFTING SLOWLY INLAND THROUGH THE AFTERNOON HOURS.
FORECAST POPS RANGE FROM 20-40 PERCENT...HIGHEST ACROSS SE NORTH
CAROLINA.
FOR TONIGHT...INLAND CONVECTIVE ACTIVITY SHOULD GRADUALLY DIMINISH
DURING THE EVENING HOURS WITH SKIES BECOMING MOSTLY CLEAR TO PARTLY
CLOUDY. SOME LOW STRATUS MAY DEVELOP VERY LATE TONIGHT INLAND AS
SATURATION OCCURS WITHIN THE BOUNDARY LAYER BUT 1000-FOOT WINDS
REMAIN A LITTLE TOO STRONG FOR FOG. LOWS WILL FALL TO 72-74 INLAND
AND 73-78 NEAR THE COAST. SOME SOUTH-FACING BEACHES COULD SEE LOW
TEMPERATURES STRUGGLE TO DROP BELOW 80 IF THE ONSHORE WIND CONTINUES
THROUGH THE NIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 AM THURSDAY...MID LEVEL RIDGE WILL REMAIN ACROSS THE AREA AS A
WESTERLY PATTERN DEVELOPS AT THE MID LEVELS. HOWEVER THERE WILL BE
INTERVALS OF RICHER THETA-E AIR TRAVERSING THE ZONAL FLOW WHICH
WARRANTS AT LEAST LOW CHANCE POPS THROUGH THE PERIOD. THE NUMEROUS
CLUSTERS OF THUNDERSTORMS WE HAVE SEEN MOVING ACROSS THE TENNESSEE
VALLEY WILL NOW TAKE AIM ON THE CAROLINAS. THE PIEDMONT TROUGH WILL
BE ENHANCED WITH THE WESTERLY FLOW WHICH WILL ASSIST IN THE FORCING
AS WELL. I HAVE MAINTAINED THE CHANCE POPS...MAINLY ON A DIURNAL
BASIS THROUGH THE PERIOD. AS WE GET CLOSER TO THE WEEKEND...THERE
WILL BE TIMES WHEN LIKELY POPS WILL BE WARRANTED BUT THIS WILL BE
BETTER ADDRESSED WITH THE NEAR TERM FORECAST. TEMPERATURE TRENDS
REMAIN RELATIVELY UNCHANGED WITH THE STRONG RIDGE AND DOWNSLOPE
COMPONENT LEADING TO READINGS SLIGHTLY ABOVE CLIMATOLOGY.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 300 AM THURSDAY...MEDIUM RANGE GUIDANCE IS TRENDING TOWARD A
RATHER WET SCENARIO FOR THE EXTENDED PERIOD. ELONGATED MID LEVEL
RIDGE SHIFTS WEST AND TROUGHING DEVELOPS ACROSS THE OHIO VALLEY.
THE TROUGH REMAINS IN PLACE AS DOES THE FRONT ASSOCIATED WITH
IT...WHICH IS POSITIONED RIGHT ACROSS OUR AREA. THIS WILL PROVIDE
A GOOF FOCUSING MECHANISM FOR INTERVALS OF SHOWERS AND
THUNDERSTORMS. HAVE INCREMENTALLY INCREASED POPS TO REPRESENT THIS
TREND. TEMPERATURES FORECAST IS ALREADY SHOWING LOWER THAN USUAL
DIURNAL RANGE WITH THE MOISTURE AND NEEDED NO CHANGES WITH THE
MORNING UPDATE.
&&
.AVIATION /07Z THURSDAY THROUGH MONDAY/...
AS OF 06Z...ISOLATED SHRA OVER THE ATLANTIC SHOULD REMAIN JUST EAST
OF THE ILM AIRPORT THROUGH DAYBREAK. ANTICIPATE DEVELOPMENT OF MVFR
CIGS ALONG THE COAST...WITH POSSIBLE IFR/LIFR INLAND DUE TO FOG &
LOW CIGS AN HOUR OR TWO BEFORE DAYBREAK. FLIGHT CATEGORY SHOULD
IMPROVE TO VFR NO LATER THAN 13-14Z. CANNOT RULE OUT ISOLATED
SHOWERS...THUS HAVE OPTED TO INTRODUCE VCSH AT ALL SITES...BEGINNING
ALONG THE COAST FIRST. SHOWERS WILL TAPER OFF IN THE EVENING HOURS.
EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS
POSSIBLE THURSDAY THROUGH SATURDAY...BECOMING SCATTERED SUNDAY AND
MONDAY. OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM THURSDAY...THE SURFACE RIDGE AXIS THAT HAS HELD OUR
WIND DIRECTIONS EASTERLY FOR THE PAST SEVERAL DAYS HAS FINALLY
BROKEN DOWN. RATHER THAN CANADIAN HIGH PRESSURE POKING DOWN FROM THE
NORTHEAST...OUR WEATHER TODAY AND TONIGHT WILL COME UNDER THE
INFLUENCE OF BERMUDA HIGH PRESSURE FROM THE EAST. THIS MEANS WINDS
WILL BECOME SOUTHERLY TODAY AND SOUTH-SOUTHWESTERLY TONIGHT...WITH
SPEEDS AVERAGING 10-12 KNOTS. SEAS ARE CURRENTLY 2-3 FT WITH PERIODS
SPLIT BETWEEN A 6 SECOND WIND WAVE AND A WEAK 9-10 SECOND SOUTHEAST
SWELL. SEAS MAY BUILD HALF A FOOT THROUGH TONIGHT AS SOUTH WINDS
FURTHER DEVELOP THE WIND WAVE COMPONENT.
RADAR CURRENTLY SHOWS ONLY ISOLATED SHOWERS OUT BEYOND 30 MILES FROM
SHORE...BUT MODELS ARE SHOWING WE SHOULD HAVE SCATTERED SHOWERS
DEVELOPING NEARSHORE NEAR AND NORTH OF CAPE FEAR THIS MORNING.
CONVECTIVE ACTIVITY SHOULD LARGELY SHIFT INLAND THIS AFTERNOON AS
THE SEABREEZE CIRCULATION BECOMES BETTER DEVELOPED.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 AM THURSDAY...ELEMENTS REMAIN THE SAME FOR THE COASTAL WATERS
THROUGH THE PERIOD AS BERMUDA HIGH PRESSURE AND THE PIEDMONT TROUGH
KEEP A SOUTHWESTERLY FLOW IN PLACE. SPEEDS REMAIN STABLE IN A RANGE
OF 10-15 KNOTS...WHICH IF ANYTHING MAY BE ON THE HIGHER END SATURDAY
AFTERNOON AS THE TROUGH STRENGTHENS. THE TEPID INCREASE IN WINDS
ISN/T ENOUGH TO IMPACT SIGNIFICANT SEAS...WHICH REMAIN IN A 2-3 FOOT
RANGE.
LONG TERM /SUNDAY THROUGH MONDAY/...
AS OF 300 AM THURSDAY...DIFFUSE FRONT WILL REMAIN JUST INLAND...AT LEAST
LOOKING AT THE LATEST WPC FORECAST AND THIS WILL KEEP A RATHER WEAK
SOUTHWESTERLY FLOW IN PLACE. SPEEDS CONTINUE TO HOVER AROUND TEN
KNOTS OR BELOW. CAN/T RULE OUT BRIEF DISRUPTIONS IN THE SYNOPTIC
FLOW WITH INTERVALS OF CONVECTION EXPECTED BUT THIS OF COURSE IS ALL
BUT IMPOSSIBLE TO FORECAST THIS FAR OUT IN TIME. SIGNIFICANT SEAS
SHOW LITTLE CHANGE AS WELL WITH 2-3 FEET AND LITTLE IN THE WAY OF A
SWELL COMPONENT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SHK
NEAR TERM...TRA
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...SGL
AREA FORECAST DISCUSSION...CORRECTED
NWS BISMARCK ND
906 PM CDT FRI AUG 9 2013
.UPDATE...
ISSUED AT 906 PM CDT FRI AUG 9 2013
MAIN UPDATE THIS EVENING WAS TO REMOVE MENTION OF PRECIPITATION
THROUGH AT LEAST 08Z SATURDAY IN THE FAR SOUTHWEST. ALSO
REDUCED/DELAYED POPS SATURDAY MORNING ACROSS FAR SOUTH CENTRAL
NORTH DAKOTA. THE LATEST HIGH RESOLUTION MODELS (HRRR/RAP) ALONG
WITH THE 00Z NAM...ARE ALL INITIALIZING/INDICATING PRECIPITATION
IN AREAS WHERE...IN REALITY...NOTHING IS OCCURRING. THE MODELS
ALREADY HAVE PRECIPITATION EITHER UP TO AND/OR IN OUR SOUTHWEST
ZONES AS OF 01Z. BUT THIS IS NOT THE CASE...HENCE THEIR SOLUTIONS
ARE PRETTY MUCH OBSOLETE FOR THE OVERNIGHT PERIOD AND INTO
SATURDAY MORNING. THE GFS/ECMWF ACTUALLY HAVE THE BEST HANDLE ON
THE CURRENT PRECIPITATION AREA...AND BOTH MODELS KEEP THE BEST
LIFT/OMEGA/PRECIPITATION SOUTH OF OUR BORDER TONIGHT. A SHORTWAVE
IS FORECAST TO MOVE ALONG THE MONTANA/WYOMING BORDER OVERNIGHT
WITH VERTICAL MOTION FIELD CONCENTRATED IN SOUTH DAKOTA. THUS
SCALED BACK POPS...AND REMOVED MENTION OF THUNDER IN FAR SOUTH
CENTRAL NORTH DAKOTA UNTIL SATURDAY AFTERNOON...AS ONLY THE FAR
SOUTHWEST WOULD BE VULNERABLE TO THUNDER LATE TONIGHT THROUGH
SATURDAY MORNING.
UPDATE ISSUED AT 541 PM CDT FRI AUG 9 2013
THE LATEST WATER VAPOR IMAGERY SHOWS NORTHERN/CENTRAL NORTH DAKOTA
DOMINATED BY NORTHWEST FLOW ALOFT...WHILE FAR SOUTHWEST/SOUTHERN
NORTH DAKOTA ARE BECOMING DETACHED FROM THE DOMINATE NORTHWEST FLOW.
HERE...WEAK RIDGING WAS OBSERVED ON WATER VAPOR WHICH EXTENDED FROM
THE FRONT RANGE OF THE ROCKIES INTO THE PANHANDLE OF IDAHO. THIS IS
INDUCING A WEST TO WEAK NORTHWEST FLOW. COUPLE OF SHORTWAVES TO NOTE
FOR TONIGHT/SATURDAY...THE FIRST WAS ALONG THE NORTHERN WYOMING AND
MONTANA BORDER...A SECOND IN CENTRAL IDAHO...AND A THIRD IN EAST
CENTRAL ALBERTA. THESE SHORTWAVES WILL TOP THE RIDGE AND SHIFT EAST
TONIGHT/SATURDAY. THE STRONGEST OMEGA/LIFT FOR TONIGHT AND SATURDAY
REMAINS IN SOUTH DAKOTA...BUT DOES GRAZE WESTERN AND SOUTHERN NORTH
DAKOTA LATER TONIGHT THROUGH SATURDAY. THE LATEST HRRR REFLECTIVITY
SUGGESTS THAT CONVECTION NOW OVER SOUTH CENTRAL MONTANA WILL SHIFT
EAST TONIGHT ALLOWING FOR THE POSSIBILITY OF ISOLATED SHOWERS IN
THE FAR SOUTHWEST AND EDGING FAIRLY CLOSE TO OUR FAR SOUTH CENTRAL
ZONES...MAINLY TOWARD AND AFTER 05Z SATURDAY. WILL CONTINUE TO
WATCH THIS ACTIVITY THIS EVENING. LATEST BOWMAN RADAR IS JUST
BEGINNING TO SHOW SOME WEAK REFLECTIVITY`S IN FAR SOUTHEAST
MONTANA. FOR THIS UPDATE...HAVE INCREASED SKY GRIDS FOR THE EARLY
PART OF THIS EVENING BASED ON VISIBLE SATELLITE AND SURFACE
OBSERVATIONS. REST OF THE FORECAST HAS THE TRENDS HANDLED WELL.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 339 PM CDT FRI AUG 9 2013
THE MAIN FORECAST ISSUE IN THE NEAR TERM IS PRECIPITATION CHANCES
TONIGHT AND SATURDAY. A WARM FRONT WILL LIFT NORTH INTO SOUTH
DAKOTA TONIGHT AS A SHORT WAVE TROUGH TOPS THE UPPER RIDGE. RAIN
COVERAGE IS EXPECTED TO REMAIN RATHER LIMITED ACROSS THE SOUTHERN
COUNTIES SO 20/30 POPS SEEM REASONABLE. SHOWERS AND ISOLATED
STORMS WILL LIKELY PUSH A BIT FARTHER NORTH INTO THE STATE ON
SATURDAY AFTERNOON. THERE SHOULD BE ENOUGH ELEVATED INSTABILITY TO
SUPPORT A FEW THUNDERSTORMS...BUT NO SEVERE WEATHER IS ANTICIPATED.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 339 PM CDT FRI AUG 9 2013
THE EXTENDED WILL BE CHARACTERIZED BY A MID/UPPER LEVEL RIDGE SLOWLY
BUILDING FROM THE ROCKIES EARLY IN THE PERIOD INTO THE CENTRAL
PLAINS BY THE END OF THE PERIOD. THIS WILL GENERATE A GRADUAL
WARMING TREND TO NEAR NORMAL TEMPERATURES BY FRIDAY.
LINGERING CONVECTION ALONG AND SOUTH OF I-94 SATURDAY EVENING SHOULD
WANE WITH THE LOSS OF DAYTIME HEATING.
AS A MID/UPPER RIDGE BUILDS INTO THE REGION...UPPER LEVEL DYNAMICS
WILL BE ON THE DECREASE. HOWEVER...LINGERING MOISTURE AND
INSTABILITY WILL GENERATE A SLIGHT CHANCE OF DIURNALLY DRIVEN
CONVECTION PRIMARILY ALONG AND WEST OF THE MISSOURI RIVER DURING THE
AFTERNOON/EVENING HOURS SUNDAY THROUGH WEDNESDAY.
THE UPPER RIDGE IS PROGGED TO BREAK DOWN SOMEWHAT THURSDAY AS A
RIDGE RUNNER CRESTS OVER THE ANTICYCLONIC RIDGE AXIS. FOR NOW
INDICATED SLIGHT CHANCE POPS AREAWIDE. HOWEVER...POPS MAY NEED TO BE
INCREASED IF FUTURE RUNS ADD CREDENCE TO THE 12Z SUITE OF MODEL
GUIDANCE.
THE RIDGE RUNNER SHORTWAVE IS THEN PROGGED TO PUSH EAST OF THE REGION
FRIDAY WITH PRECIP CHANCES ENDING FROM WEST TO EAST. HIGHS FRIDAY
LOOK TO RANGE FROM THE LOWER 80S EAST TO THE UPPER 80S WEST.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 541 PM CDT FRI AUG 9 2013
KMOT AND KJMS WILL BEGIN WITH LOW VFR CIGS AT 00Z SATURDAY WITH
IMPROVEMENTS TO SCT VFR BY AROUND 03Z. OVERALL SCT/BKN LOW TO MID
LEVEL CLOUDS WILL DOMINATE THROUGH SATURDAY...WITH A VCSH IN
KDIK/KBIS/KJMS UNTIL THE PRECIPITATION AREA BECOMES BETTER APPARENT
FOR PREDOMINANT CONDITIONS. KISN/KMOT LOOK TO BE FAR ENOUGH REMOVED
FROM ANY MENTION OF PRECIPITATION NEXT 24HR.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...RP KINNEY
LONG TERM...TM
AVIATION...KS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
902 PM CDT FRI AUG 9 2013
.UPDATE...
ISSUED AT 902 PM CDT FRI AUG 9 2013
MAIN UPDATE THIS EVENING WAS TO REMOVE MENTION OF PRECIPITATION
THROUGH AT LEAST 08Z SATURDAY IN THE FAR SOUTHWEST. ALSO
REDUCED/DELAYED POPS SATURDAY MORNING ACROSS FAR SOUTH CENTRAL
NORTH DAKOTA. THE LATEST HIGH RESOLUTION MODELS (HRRR/RAP) ALONG
WITH THE 00Z NAM...ARE ALL INITIALIZING/INDICATING PRECIPITATION
IN AREAS WHERE...IN REALITY...NOTHING IS OCCURRING. THE MODELS
ALREADY HAVE PRECIPITATION EITHER UP TO AND/OR IN OUR SOUTHWEST
ZONES AS OF 01Z. BUT THIS IS NOT THE CASE...HENCE THEIR SOLUTIONS
ARE PRETTY MUCH OBSOLETE FOR THE OVERNIGHT PERIOD AND INTO
SATURDAY MORNING. THE GFS/ECMWF ACTUALLY HAVE THE BEST HANDLE ON
THE CURRENT PRECIPITATION AREA...AND BOTH MODELS KEEP THE BEST
LIFT/OMEGA/PRECIPITATION SOUTH OF OUR BORDER TONIGHT. A SHORTWAVE
IS FORECAST TO MOVE ALONG THE MONTANA/WYOMING BORDER OVERNIGHT
WITH VERTICAL MOTION FIELD CONCENTRATED IN SOUTH DAKOTA. THUS
SCALED BACK POPS...AND REMOVED MENTION OF THUNDER UNTIL SATURDAY
AFTERNOON AS LITTLE INSTABILITY IS FORECAST UNTIL THEN.
UPDATE ISSUED AT 541 PM CDT FRI AUG 9 2013
THE LATEST WATER VAPOR IMAGERY SHOWS NORTHERN/CENTRAL NORTH DAKOTA
DOMINATED BY NORTHWEST FLOW ALOFT...WHILE FAR SOUTHWEST/SOUTHERN
NORTH DAKOTA ARE BECOMING DETACHED FROM THE DOMINATE NORTHWEST FLOW.
HERE...WEAK RIDGING WAS OBSERVED ON WATER VAPOR WHICH EXTENDED FROM
THE FRONT RANGE OF THE ROCKIES INTO THE PANHANDLE OF IDAHO. THIS IS
INDUCING A WEST TO WEAK NORTHWEST FLOW. COUPLE OF SHORTWAVES TO NOTE
FOR TONIGHT/SATURDAY...THE FIRST WAS ALONG THE NORTHERN WYOMING AND
MONTANA BORDER...A SECOND IN CENTRAL IDAHO...AND A THIRD IN EAST
CENTRAL ALBERTA. THESE SHORTWAVES WILL TOP THE RIDGE AND SHIFT EAST
TONIGHT/SATURDAY. THE STRONGEST OMEGA/LIFT FOR TONIGHT AND SATURDAY
REMAINS IN SOUTH DAKOTA...BUT DOES GRAZE WESTERN AND SOUTHERN NORTH
DAKOTA LATER TONIGHT THROUGH SATURDAY. THE LATEST HRRR REFLECTIVITY
SUGGESTS THAT CONVECTION NOW OVER SOUTH CENTRAL MONTANA WILL SHIFT
EAST TONIGHT ALLOWING FOR THE POSSIBILITY OF ISOLATED SHOWERS IN
THE FAR SOUTHWEST AND EDGING FAIRLY CLOSE TO OUR FAR SOUTH CENTRAL
ZONES...MAINLY TOWARD AND AFTER 05Z SATURDAY. WILL CONTINUE TO
WATCH THIS ACTIVITY THIS EVENING. LATEST BOWMAN RADAR IS JUST
BEGINNING TO SHOW SOME WEAK REFLECTIVITY`S IN FAR SOUTHEAST
MONTANA. FOR THIS UPDATE...HAVE INCREASED SKY GRIDS FOR THE EARLY
PART OF THIS EVENING BASED ON VISIBLE SATELLITE AND SURFACE
OBSERVATIONS. REST OF THE FORECAST HAS THE TRENDS HANDLED WELL.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 339 PM CDT FRI AUG 9 2013
THE MAIN FORECAST ISSUE IN THE NEAR TERM IS PRECIPITATION CHANCES
TONIGHT AND SATURDAY. A WARM FRONT WILL LIFT NORTH INTO SOUTH
DAKOTA TONIGHT AS A SHORT WAVE TROUGH TOPS THE UPPER RIDGE. RAIN
COVERAGE IS EXPECTED TO REMAIN RATHER LIMITED ACROSS THE SOUTHERN
COUNTIES SO 20/30 POPS SEEM REASONABLE. SHOWERS AND ISOLATED
STORMS WILL LIKELY PUSH A BIT FARTHER NORTH INTO THE STATE ON
SATURDAY AFTERNOON. THERE SHOULD BE ENOUGH ELEVATED INSTABILITY TO
SUPPORT A FEW THUNDERSTORMS...BUT NO SEVERE WEATHER IS ANTICIPATED.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 339 PM CDT FRI AUG 9 2013
THE EXTENDED WILL BE CHARACTERIZED BY A MID/UPPER LEVEL RIDGE SLOWLY
BUILDING FROM THE ROCKIES EARLY IN THE PERIOD INTO THE CENTRAL
PLAINS BY THE END OF THE PERIOD. THIS WILL GENERATE A GRADUAL
WARMING TREND TO NEAR NORMAL TEMPERATURES BY FRIDAY.
LINGERING CONVECTION ALONG AND SOUTH OF I-94 SATURDAY EVENING SHOULD
WANE WITH THE LOSS OF DAYTIME HEATING.
AS A MID/UPPER RIDGE BUILDS INTO THE REGION...UPPER LEVEL DYNAMICS
WILL BE ON THE DECREASE. HOWEVER...LINGERING MOISTURE AND
INSTABILITY WILL GENERATE A SLIGHT CHANCE OF DIURNALLY DRIVEN
CONVECTION PRIMARILY ALONG AND WEST OF THE MISSOURI RIVER DURING THE
AFTERNOON/EVENING HOURS SUNDAY THROUGH WEDNESDAY.
THE UPPER RIDGE IS PROGGED TO BREAK DOWN SOMEWHAT THURSDAY AS A
RIDGE RUNNER CRESTS OVER THE ANTICYCLONIC RIDGE AXIS. FOR NOW
INDICATED SLIGHT CHANCE POPS AREAWIDE. HOWEVER...POPS MAY NEED TO BE
INCREASED IF FUTURE RUNS ADD CREDENCE TO THE 12Z SUITE OF MODEL
GUIDANCE.
THE RIDGE RUNNER SHORTWAVE IS THEN PROGGED TO PUSH EAST OF THE REGION
FRIDAY WITH PRECIP CHANCES ENDING FROM WEST TO EAST. HIGHS FRIDAY
LOOK TO RANGE FROM THE LOWER 80S EAST TO THE UPPER 80S WEST.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 541 PM CDT FRI AUG 9 2013
KMOT AND KJMS WILL BEGIN WITH LOW VFR CIGS AT 00Z SATURDAY WITH
IMPROVEMENTS TO SCT VFR BY AROUND 03Z. OVERALL SCT/BKN LOW TO MID
LEVEL CLOUDS WILL DOMINATE THROUGH SATURDAY...WITH A VCSH IN
KDIK/KBIS/KJMS UNTIL THE PRECIPITATION AREA BECOMES BETTER APPARENT
FOR PREDOMINANT CONDITIONS. KISN/KMOT LOOK TO BE FAR ENOUGH REMOVED
FROM ANY MENTION OF PRECIPITATION NEXT 24HR.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...RP KINNEY
LONG TERM...TM
AVIATION...KS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
457 PM CDT THU AUG 8 2013
.UPDATE...
ISSUED AT 457 PM CDT THU AUG 8 2013
LATEST WATER VAPOR IMAGERY SHOWS NORTHWEST FLOW CONTINUING WITH AN
UPSTREAM MID LEVEL SHORTWAVE LOCATED IN SOUTH CENTRAL SASKATCHEWAN.
REGIONAL RADAR SHOWS ISOLATED RAIN SHOWERS JUST NORTH OF THE MONTANA
BORDER MOVING SOUTHEAST WITH TIME. LIGHT RAIN AT SWIFT CURRENT PER
LATEST SURFACE OBSERVATIONS AND THE GFS HAS THE BEST HANDLE ON THE
PRECIPITATION AREA...WITH THE RAP NOT FAR BEHIND. THE GFS HOLDS A
THIN AREA OF LIGHT SHOWERS TOGETHER AS THEY MOVE INTO NORTHWESTERN
NORTH DAKOTA THIS EVENING AND WILL FOLLOW. THE RAP SHOWS A WEAKENING
OF THE SHOWERS AND KEEPS IT DRY. BASED ON THE LATEST RADAR AND
SURFACE OBSERVATIONS...THINK ENOUGH EVIDENCE UPSTREAM AND IN THE
GFS SOLUTION TO SOLIDIFY A MENTION OF ISOLATED SHOWERS NORTHWEST
INTO PORTIONS OF NORTH CENTRAL TONIGHT. THE GFS H7-H5 RELATIVE
HUMIDITY FIELD ALSO MATCHES THE VISIBLE SATELLITE IMAGERY WELL WHEN
OVERLAID AND THUS WILL INCREASE SKY GRIDS A BIT TO CAPTURE THIS.
ALSO AS MENTIONED FROM THE PREVIOUS DISCUSSION BELOW THE OTHER INTEREST
OVERNIGHT COULD BE OUR FAR SOUTHWEST ZONES...WHERE CONVECTION OVER
NORTHERN WYOMING THIS AFTERNOON IS FORECAST TO BUILD FURTHER NORTH
AND POSSIBLY SEEP INTO THE SOUTHWEST BY AROUND 04Z FRIDAY...PER
RAP MODEL. THE HRRR MODEL HAS CHANGED ITS COURSE BY KEEPING THE
REFLECTIVITY`S SOUTH WHEREAS EARLIER IT ALSO MAKE A TRACK INTO
SOUTHWEST NORTH DAKOTA. WILL CONTINUE TO MONITOR...OTHERWISE
MOSTLY CLEAR TO PARTLY CLOUDY SKIES CAN BE ANTICIPATED FOR THE
REST OF WESTERN AND CENTRAL NORTH DAKOTA THIS EVENING INTO TONIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 317 PM CDT THU AUG 8 2013
CURRENTLY...HIGH PRESSURE CONTINUES TO BUILD ACROSS WESTERN AND
CENTRAL NORTH DAKOTA. THE COOL HIGH PRESSURE SUPPRESS AND
THUNDERSTORM ACTIVITY LAT THIS AFTERNOON AND TONIGHT. BUT A FEW
SPRINKLES OR AN ISOLATED SHOWER CANNOT BE RULED OUT LATE THIS
AFTERNOON.
TONIGHT...THE SURFACE HIGH PRESSURE RIDGE REMAINS SITUATED
NORTHWEST TO SOUTHEAST ACROSS THE CWA...WHILE SHORTWAVE ENERGY
APPROACHES EASTERN NORTH DAKOTA AND ALSO SOUTHWEST NORTH DAKOTA.
THIS WILL LIKELY RESULT IN LITTLE MORE THAN INCREASING CLOUDS OVER
THE SOUTHWEST AND SOUTH CENTRAL LATE TONIGHT. SOME OF THE MODELS
ARE INDICATING VERY LIGHT QPF IN THE SOUTHWEST BETWEEN 06-12Z
FRIDAY. BUT FOR NOW KEPT WITH THE CURRENT DRY FORECAST. EXPECT A
COOL NIGHT WITH HIGHS RANGING FROM THE MID 40S FAR NORTH TO THE
LOW TO MID 50S FAR SOUTH.
SHORTWAVE ENERGY WORKING THROUGH A NORTHERN ROCKIES UPPER RIDGE
WILL SUPPORT SHOWERS AND THUNDERSTORMS ACROSS SOUTHEAST
MONTANA...NORTHERN WYOMING AND WESTERN SOUTH DAKOTA FRIDAY
AFTERNOON. IT IS POSSIBLE THAT A FEW OF THESE SHOWERS OR
THUNDERSTORMS COULD MOVE INTO THE SOUTHWEST FRIDAY AFTERNOON.
HOWEVER...GUIDANCE CONTINUES TO TREND FARTHER SOUTH SO WILL
CONTINUE WITH PERSISTENCE AND KEEP THINGS DRY ON FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 317 PM CDT THU AUG 8 2013
A SLOW WARMING TREND POTENTIALLY BACK TO NEAR NORMAL TEMPERATURES
NEXT WEEK WILL HIGHLIGHT THE EXTENDED FORECAST.
THE 12 UTC GUIDANCE SUITE IS IN GOOD AGREEMENT ON NORTHWEST FLOW
ALOFT CONTINUING THROUGH MONDAY...BEFORE A POTENTIAL SHIFT OF THE
UPPER LEVEL RIDGE AXIS ACROSS THE NORTHERN PLAINS TUESDAY ONWARD.
THIS WOULD SUPPORT A SLOW WARMING TREND FROM THE RECENT BELOW NORMAL
TEMPERATURES TO WIDESPREAD HIGHS IN THE 80S BY MID TO LATE NEXT
WEEK. IN REGARDS TO PRECIPITATION CHANCES...THERE IS CHANCE OF
THUNDERSTORMS SATURDAY AND SATURDAY NIGHT AS THE LAST OF THE
SIGNIFICANT WAVES EMBEDDED IN NORTHWEST FLOW PROPAGATES ACROSS THE
NORTHERN PLAINS. THEREAFTER...THUNDERSTORM CHANCES HOLD OFF UNTIL
MID TO LATE NEXT WEEK WITH INCREASING MOISTURE TRANSPORT UNDER THE
RIDGE AHEAD OF LEE SURFACE LOW PRESSURE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 457 PM CDT THU AUG 8 2013
VFR CIGS/VSBYS EXPECTED NEXT 24HR. A WEAK DISTURBANCE IN SOUTH
CENTRAL SASKATCHEWAN WILL GRAZE KISN WITH A VCSH THROUGH 06Z
TONIGHT AND A VCSH INTO KMOT BETWEEN 06Z-12Z FRIDAY. OTHERWISE SCT
TO BKN MID LEVEL CLOUDS WILL MOVE INTO WESTERN AND CENTRAL NORTH
DAKOTA TONIGHT WITH DRY WEATHER ANTICIPATED OVER KDIK/KBIS/KJMS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...TWH
LONG TERM...AYD
AVIATION...KS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1242 AM CDT THU AUG 8 2013
.UPDATE...
ISSUED AT 1242 AM CDT THU AUG 8 2013
LINGERING ISOLATED LIGHT RAIN SHOWERS OVER SOUTH CENTRAL NORTH
DAKOTA WERE ASSOCIATED WITH WEAK UPPER LEVEL IMPULSES MOVING
SOUTHEASTWARD ACROSS THE STATE. CURRENT FORECAST ON TRACK
REGARDING THIS...AS WELL AS WINDS AND TEMPERATURES FOR THE
OVERNIGHT HOURS.
UPDATE ISSUED AT 903 PM CDT WED AUG 7 2013
MAIN UPDATE WAS TO REMOVE MENTION OF THUNDER FOR ALL BUT THE
SOUTHWEST UNTIL MIDNIGHT...THEN REMOVE THUNDER ALTOGETHER. LATEST
WATER VAPOR IMAGERY SHOWED A SHORTWAVE NOW OVER WESTERN NORTH
DAKOTA...WITH A NARROW BAND OF LIFT/RAIN SHOWERS SOUTH OF HIGHWAY
2...FROM NEAR NEW TOWN EAST TO HARVEY. THIS AREA WAS CONTINUING TO
SAG SOUTH WHILE CONTINUING TO ADVANCE EAST. LOCAL RADAR WAS ALSO
SHOWING A WEAK LINE OF SHOWERS EXTENDING FROM GARRISON SOUTH TO
BISMARCK. SPC MESO-ANALYSIS SHOWS MID LEVEL LAPSE RATES INCREASING
IN RESPONSE TO THE SHORTWAVE IN WESTERN NORTH DAKOTA. WITH 50KT
0-6KM SHEAR IN THE SOUTHWEST...WILL CONTINUE TO MENTION ISOLATED
THUNDERSTORMS. A LACK OF INSTABILITY ELSEWHERE WILL INHIBIT ANY
THREAT OF THUNDERSTORMS. THE RAP AND 00Z NAM MAINTAIN THE IDEA THAT
ISOLATED SHOWERS WILL CONTINUE TO PUSH SOUTH TO THE BORDER THROUGH
12Z THURSDAY. CONCUR WITH THIS IDEA BASED ON THE POSITION AND
MOVEMENT OF THE AFOREMENTIONED SHORTWAVE. MINOR UPDATES TO
POPS/SKY/WX AND HOURLY TEMPERATURES.
UPDATE ISSUED AT 542 PM CDT WED AUG 7 2013
LATEST WATER VAPOR IMAGERY SHOWS A SHORTWAVE NOW WORKING ITS WAY
INTO NORTHEAST MONTANA FROM SOUTHERN SASKATCHEWAN. AN AREA OF RAIN
SHOWERS CONTINUE TO MOVE INTO NORTHWEST NORTH DAKOTA. THE LATEST
RAP HAS A GOOD READ ON THE ACTIVITY AS SCOOTS IT ACROSS THE NORTH
CENTRAL THIS EVENING. IN ADDITION...WILL WATCH FOR SHOWERS TO
DEVELOP IN THE WEST AND SOUTH CENTRAL EARLY TONIGHT PER RAP MODEL.
RADAR SHOWING A WEAK LINE TRYING TO GENERATE FROM NEAR WILLISTON
SOUTH TO TROTTERS AT THIS MOMENT. BEST FORCING REMAINS NORTH. THUS
WILL CONTINUE WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS NORTH
THIS EVENING AND ISOLATED SHOWERS/THUNDERSTORMS WEST AND CENTRAL
OVERNIGHT. GIVEN THE WEAK INSTABILITY...THUNDER SHOULD REMAIN
ISOLATED. MINOR UPDATES TO HOURLY TEMPS/DEWPOINTS AND CHANGED
UNCERTAINTY WORDING TO AREAL COVERAGE IN THE WEATHER GROUP BASED
ON RADAR.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 338 PM CDT WED AUG 7 2013
CURRENTLY...A STRONG UPPER LEVEL JET AND A SHORTWAVE IMPULSE
TRACKING ACROSS SOUTHERN SASKATCHEWAN IS RESPONSIBLE FOR PRODUCING
SCATTERED SHOWERS FROM NORTHEAST MONTANA INTO NORTHWEST NORTH
DAKOTA. THE SHOWERS ARE EXPECTED TO TRACK EAST AND SOUTH ACROSS
THE AREA LATE THIS AFTERNOON AND THIS EVENING. SIMILAR TO THE
TRACK OF A SHORTWAVE YESTERDAY. THE MAIN DIFFERENCE IS THE
ATMOSPHERE IS MORE STABLE TODAY. HOWEVER...WITH A STRONG UPPER
LEVEL JET AND SHORTWAVE...WE CANNOT RULE OUT A FEW THUNDERSTORMS
THIS AFTERNOON AND EARLY EVENING...WITH SMALL HAIL AND GUSTY
WINDS. HOWEVER IN THE FORECAST WE LIMITED THE BEST CHANCES TO THE
NORTH LATE THIS AFTERNOON...AND WITH LIMITED INSTABILITY AND
CAPPING ALOFT...WE KEPT A MENTION OF SHOWERS WITH ONLY ISOLATED
THUNDERSTORMS. EXPECT PRECIPITATION CHANCES TO DIMINISH AS THE
SYSTEM TRACKS SOUTHEAST. BUT THE LATEST RAP AND HRRR HOLD
REFLECTIVITIES TOGETHER AS THEY TRACK INTO THE SOUTHEAST CWA
AROUND MIDNIGHT.
MODELS HAVE TRENDED FARTHER SOUTH WITH THE NEXT WAVE COMING INTO
THE AREA AFTER MIDNIGHT. HAVE THEREFORE CONTINUED THE TREND OF
LOWERING POPS ACROSS THE AREA. CURRENTLY HAVE CHANCE POPS ACROSS
THE FAR SOUTHWEST AND SOUTH CENTRAL LATE TONIGHT...AND HAVE
DROPPED POPS ACROSS THE SOUTH ON THURSDAY MORNING. ANOTHER
SHORTWAVE MOVING ACROSS ALBERTA TONIGHT WILL DROP SOUTHEAST INTO
THE LOCAL AREA THURSDAY AFTERNOON. THIS COULD DEVELOP AN ISOLATED
SHOWERS ACROSS THE NORTH DURING THE AFTERNOON. TEMPERATURES WILL
REMAIN ON THE COOL SIDE WITH HIGHS RANGING FROM THE 60S NORTH TO
THE 70S SOUTH.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 338 PM CDT WED AUG 7 2013
CONTINUED BELOW NORMAL TEMPERATURES WILL HIGHLIGHT THE EXTENDED
FORECAST.
AS HAS BEEN THE PATTERN OVER THE LAST COUPLE WEEKS...NORTHWEST
FLOW ALOFT WILL CONTINUE ACROSS THE NORTHERN PLAINS THROUGH THE
EXTENDED. THIS FAVORS BELOW NORMAL TEMPERATURES WITH HIGHS
GENERALLY IN THE 70S...PERHAPS RECOVERING INTO THE LOWER 80S BY
MID NEXT WEEK. OVERALL...THE COOLER EDGE OF GUIDANCE HAS BEEN
HANDLING THIS PATTERN BETTER...AND THUS UTILIZED A BLEND OF THE
BIAS CORRECTED 12 UTC SUITE. IN REGARDS TO PRECIPITATION...WHILE
ISOLATED DIURNAL CONVECTION IS HARD TO RULE OUT ANY DAY UNDER
NORTHWEST FLOW...THE FAVORED PERIODS FOR PRECIPITATION ARE SATURDAY
WITH LEE SURFACE LOW PRESSURE AND AGAIN TUESDAY INTO WEDNESDAY AS
PACIFIC ENERGY CRESTS THE UPPER LEVEL INTERMOUNTAIN WEST RIDGE AND
PROPAGATES INTO THE NORTHERN PLAINS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1242 AM CDT THU AUG 8 2013
SCT TO BKN VFR CIGS EXPECTED THROUGH THE TAF PERIOD. NOT MUCH
CHANGE IN SYNOPTIC PATTERN THIS 24 HOUR TIME PERIOD WITH SURFACE
HIGH PRESSURE IN CANADA PUSHING SOUTHWARD FARTHER INTO NORTH
DAKOTA...AND UPPER LEVEL DISTURBANCES IN THE NORTHWEST FLOW ALOFT.
LIGHT EAST TO NORTHERLY WINDS WITH NO MENTION OF PRECIPITATION
EXCEPT FOR AT KJMS EARLY IN THE TAF PERIOD WITH LINGERING LIGHT
SHOWERS OVER SOUTH CENTRAL NORTH DAKOTA UNTIL AROUND 12Z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JV
SHORT TERM...TWH
LONG TERM...AYD
AVIATION...JV
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
423 PM EDT THU AUG 8 2013
.SYNOPSIS...
A SLOW MOVING FRONTAL SYSTEM WILL PUSH SOUTHEAST TOWARD THE OHIO
RIVER TONIGHT AND FRIDAY. THE FRONT WILL CONTINUE TO PUSH FARTHER
SOUTH FRIDAY NIGHT INTO SATURDAY AS HIGH PRESSURE AND DRIER AIR
BEGIN TO BUILD INTO THE GREAT LAKES. IN THE MEANTIME...A MOIST
AIRMASS WILL ACCOMPANY THE FRONT WITH THE THREAT OF SHOWERS AND
THUNDERSTORMS...AND LOCALLY HEAVY RAINFALL...EXPECTED THROUGH
FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
WILL RELY ON THE RAP AND HRRR MODELS FOR THE NEAR TERM. AS
HELPFUL AS THE MODELS HAVE BEEN IN THE IMMEDIATE NEAR TERM...THE
EVOLUTION OF CONVECTION OVERNIGHT INTO FRIDAY MORNING CONTINUES TO
OSCILLATE WITH EACH SUCCESSIVE RUN...SO WILL DISCUSS THE UNCERTAINTIES
IN THE FORECAST.
A FRONTAL BOUNDARY WAS NEARLY STATIONARY ACRS THE FORECAST AREA
THIS AFTERNOON. SYNOPTIC AND MESOSCALE ANALYSIS SHOWS THAT A WEAK
WAVE OF LOW PRESSURE WAS LOCATED BETWEEN DAYTON AND COLUMBUS. THIS
WAVE ALONG WITH WEAK FRONTAL CONVERGENCE...HAVE LED TO NUMEROUS
SHOWERS AND EMBEDDED THUNDERSTORMS IN THIS REGION WITH SCATTERED
CONVECTION TO THE SOUTH DUE TO THE DAYTIME HEATING AND A MOIST
AIRMASS. THIS WAVE IS EXPECTED TO RIPPLE TO THE NE THIS EVENING...ONLY
TO BE REPLACED BY ANOTHER WAVE OF LOW PRESSURE OVERNIGHT. THE
FOCUS FOR TONIGHT HAS BEEN PLACED ON AN APPARENT MCV CURRENTLY
OVER SRN ILLINOIS PER VISIBLE SATELLITE IMAGERY. THIS MCV IS
FORECAST TO DRIFT ENE THROUGH THE OHIO VALLEY OVERNIGHT. AS IT
DOES...IT SHOULD BE ACCOMPANIED BY A WEAK WAVE OF LOW PRESSURE AT
THE SFC. THE AIRMASS CONTINUES TO SUFFICIENTLY DESTABILIZE AHEAD OF
THIS FEATURE...AND PER MODELS...SHOULD RESULT IN AN UPTICK OF
CONVECTION TO OUR WEST LATE THIS AFTERNOON AND EARLY EVENING AS
THE MCV INTERACTS WITH THIS AIRMASS. THE QUESTION REMAINS HOW AND
WHERE WILL THE BEST FORCING OCCUR AS THE MCV TRAVERSES THE AREA
FROM WEST TO EAST OVERNIGHT. MODELS SUGGEST THAT A SUBTLE LOW
LEVEL JET AND THUS AN INCREASE IN 850 MB MOISTURE TRANSPORT SHOULD
OCCUR AS CONVECTION TRANSITIONS FROM SURFACE BASED TO ELEVATED
BASED. MODELS CONTINUE TO SHOW THAT PWATS WILL BE IN EXCESS OF 2
INCHES WITH THIS FEATURE...ALONG WITH WARM CLOUD DEPTHS IN EXCESS
OF 4 KMS...WHICH FAVORS A COLLISION/COALESCENCE PROCESS. AS A
RESULT...THE THREAT IS THERE FOR VERY HEAVY RAINFALL TO
OCCUR...ESPECIALLY WITH THE MORE INTENSE THUNDERSTORMS. IN
ADDITION...CONVECTION WILL BE SLOW MOVING AND COULD TRAIN OVER THE
SAME AREAS. ALL THESE INGREDIENTS POINT TO AN ENHANCED FLASH FLOOD
THREAT. DURING THE AFTN FORECAST PROCESS...THE RAP AND HRRR
INDICATED THAT THE MCV AND LOW LEVEL JET WOULD INTERACT WITH THE
FRONTAL BOUNDARY TO PRODUCE LIKELY POPS ACRS MUCH OF THE REGION
OVERNIGHT. AS SUCH...FELT AT THE TIME THAT A FFA WAS NEED FOR MOST
OF THE AREA EXCEPT THE FAR NORTHWEST COUNTIES. LATER HRRR AND RAP
RUNS HAVE NOW BEEN SUGGESTING THAT THE MAIN FOCUS MAIN BE MORE ALONG
AND SOUTH OF THE OHIO RIVER. WILL CONTINUE TO MONITOR THIS TO SEE
IF THIS CONTINUES TO TREND THIS WAY. OTHERWISE...WILL STICK TO
THE ORIGINAL THINKING. CONVECTION IS EXPECTED TO WANE TOWARD
MORNING FROM WEST TO EAST AS THE MCV AND SFC WAVE RIPPLE AND THE
FRONTAL BOUNDARY SLOWLY SETTLES TOWARD THE OHIO RIVER. IT MUST BE
POINTED OUT THAT ANOTHER MCV IS UPSTREAM OF THE CURRENT MCV AND IT
IS UNCERTAIN HOW THIS WILL INTERACT WITH THE REGION TOWARD MORNING.
ATTM...HAVE ISSUED A 2 SEGMENTED FFA WITH THE NW 1/2 DROPPING OFF BY
12Z FRIDAY AS CONVECTION SHOULD BECOME MORE FOCUSED TOWARD THE
OHIO RIVER VALLEY. THE SECOND SEGMENT WILL GO UNTIL 00Z SATURDAY.
LOWS TONIGHT WILL RANGE FROM THE MID 60S FAR NW TO THE LOWER 70S
ALONG AND SOUTH OF THE OHIO RIVER.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
FRONTAL BOUNDARY WILL SLOWLY DROP SOUTHEAST TOWARD THE OHIO RIVER ON
FRIDAY...THEN SOUTH OF THE OHIO RIVER BY SATURDAY MORNING. HAVE
CONTINUED WITH A CHANCE OF SHOWERS AND THUNDERSTORMS...WITH LIKELY
POPS GIVEN TO LOCATIONS ALONG AND SOUTHEAST OF THE FRONT FRIDAY
AFTERNOON DUE TO DIURNAL HEATING AND ANY POSSIBLE DISTURBANCES
ALOFT PASSING BY. AGAIN...THE THREAT OF HEAVY RAIN WILL CONTINUE
AND THIS IS WHY THE 2 SEGMENT FFA WILL CONTINUE UNTIL 00Z
SATURDAY. INTENSITY AND COVERAGE OF PCPN SHOULD WANE FRIDAY NIGHT
AS THE ATMOSPHERE STABILIZES...AND FRONTAL CONVERGENCE SHIFTS
FARTHER SOUTH. DRIER AIR WILL BEGIN TO BUILD INTO THE NRN ZONES
FRIDAY NIGHT AS HIGH PRESSURE MOVES INTO THE GREAT LAKES REGION.
HIGHS ON FRIDAY WILL BE CLOUD AND PCPN DEPENDENT BUT SHOULD RANGE
FROM THE LOWER TO MID 80S. LOWS FRIDAY NIGHT WILL RANGE FROM THE
LOWER 60S NW TO THE UPPER 60S ALONG AND SOUTH OF THE OHIO RIVER.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
COLD FRONT MAY STILL BE LINGERING IN THE FAR SOUTHERN PART OF THE
FORECAST AREA AT THE BEGINNING OF THE PERIOD BEFORE FINALLY PUSHING
OFF TO THE SOUTH. SO KEPT CHANCE POPS INTO SATURDAY NEAR THIS
BOUNDARY. WENT SLIGHTLY BELOW MOS FOR HIGHS AND THEN LEANED TOWARDS
COOLER NAM GUIDANCE FOR SATURDAY NIGHT LOWS.
HIGH PRESSURE WILL BUILD IN SUNDAY AND MOVE OFF TO THE EAST ON
MONDAY. TEMPERATURES WILL BE NEAR NORMAL DURING THIS TIME FRAME. A
DEVELOPING UPPER TROUGH WILL PUSH A COLD FRONT INTO THE REGION
MONDAY NIGHT INTO TUESDAY. THIS WILL RESULT IN THE NEXT CHANCE OF
SHOWERS AND THUNDERSTORMS. RIDGING WILL RETURN WEDNESDAY AND
THURSDAY AS HIGH PRESSURE SETTLES OVER THE GREAT LAKES BRINGING
ANOTHER COOL AND DRY AIR MASS.
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
MODERATELY UNSTABLE ATMOSPHERE HAS ACTIVATED AHEAD OF THE CDFNT
WORKING INTO THE REGION. EXPECT CONVECTION TO CONTINUE INTO THE
EVENING WITH THE WEAK FRONTAL CONVERGENCE AND BOUNDARIES ACTING AS
FORCING.
LOOKING TOWARDS OVERNIGHT HOURS...AFT 02Z..,GETTING A WHOLE BUNCH
OF DIFFERENT ANSWERS FROM THE MODELS. SYSTEM OUT OVER MO ATTM
HEADS EAST. MODELS ARE SHOWING DIFFERENT TIMING AND TRACK OF THE
SYSTEM HAS IT APPROACHES THE AREA. THE NAM WEAKENS AND SHUNTS THE
SYSTEM S OF THE TAFS...KEEPING THINGS PRETTY DRY ON FRIDAY. THE 2
CMC MODELS ALONG WITH THE ECMWF BRING IT IN TOWARDS 12Z AND GIVE THE
SRN TAFS THE BEST CHC OF PCPN. THE GFS MEANWHILE LIFTS SI UP RIGHT
ACROSS THE FA ON FRIDAY. LEANED TOWARDS THE MAJORITY FORECAST AND
BROUGHT VCTS/VCSH INTO THE KCVG/KLUK AROUND 09Z. ALSO ABOUT THIS
TIME REDEVELOPED THE FOG AND STRATUS AGAIN. THIS FAR OUT DID NOT
HAVE THE CONFIDENCE TO GO IFR...ESPECIALLY IF WE GET A LOT OF
MIXING FROM PCPN.
THREW A VCSH AT KDAY AND KILN AFT 15Z AS HEATING OF THE ATMOSPHERE
MAY ALLOW CONVECTION TO INITIATE AGAIN AFTER ST BEGINS TO LIFT.
OUTLOOK...THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE AT TIMES
THROUGH FRIDAY....THEN AGAIN MONDAY NIGHT INTO TUESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...FLASH FLOOD WATCH THROUGH FRIDAY MORNING FOR OHZ042>046-
051>056-060>065-070>072.
FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR OHZ073-074-
077>082-088.
KY...FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR KYZ089>100.
IN...FLASH FLOOD WATCH THROUGH FRIDAY MORNING FOR INZ050-058-059-
066-073-074.
FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR INZ075-080.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...HICKMAN
SHORT TERM...HICKMAN
LONG TERM...
AVIATION...SITES
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
208 AM EDT THU AUG 8 2013
.SYNOPSIS...
A COLD FRONT WILL SLOWLY PUSH INTO THE REGION TONIGHT AND THURSDAY.
THE FRONT WILL EVENTUALLY STALL CLOSE TO THE OHIO RIVER BY FRIDAY
MORNING. THIS FRONTAL BOUNDARY WILL THEN OSCILLATE NEAR THE OHIO
RIVER THROUGH THE WEEKEND. THE THREAT OF SHOWERS AND THUNDERSTORMS
WILL CONTINUE THROUGH THE PERIOD...ESPECIALLY FOR THOSE LOCATIONS
CLOSER TO THE FRONTAL BOUNDARY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
HAVE UPDATED PRIMARILY TO ACCOUNT FOR SHOWERS AND THUNDERSTORMS
OVER PORTIONS OF NORTHERN KENTUCKY SOUTH OF METRO CINCINNATI. A
WEAK INFLECTION RUNNING ALONG BUT JUST SOUTHEAST OF THE I-71
CORRIDOR MAY HAVE AN ENHANCED POTENTIAL FOR SHOWERS THIS EVENING
BUT ONLY FOR THE NEXT HOUR OR TWO. UPSTREAM STORMS OVER INDIANA DO
NOT POSE A THREAT TO US IN THE NEXT 3-5 HOURS AND THE STORMS OVER
KY WILL BE DYING OUT AS THEY SLOWLY MOVE ENE. BLENDED INTO THE
30ISH POPS TOWARDS DAYBREAK THAT WERE IN EARLIER FORECAST AND
TRIED TO PLAY DOWN THE THREAT ELSEWHERE...AT LEAST FOR THE EARLY
PART OF THE OVERNIGHT.
HAVE USED A BLEND OF THE HRRR AND NAM FOR THE NEAR TERM FORECAST.
A COLD FRONT WAS POISED TO OUR NORTHWEST THIS EVENING. THIS FRONT
IS FORECAST TO SLOWLY SINK SOUTHEAST TOWARD THE AREA OVERNIGHT.
CURRENT THINKING IS THAT CONVECTIVE ACTIVITY NEAR THE FRONT WILL
DIMINISH THIS EVENING WITH THE LOSS OF DAYTIME HEATING AND
FORCING. LATEST MODEL RUNS NOW SUGGEST THAT SUBTLE LOW LEVEL JET
AND ASSOCIATED UPR LVL DISTURBANCE WILL LIKELY STAY TO OUR SOUTH
AND SOUTHWEST OVERNIGHT. AS A RESULT...WITH VERY WEAK
FORCING...CAN NOT SEE GOING MUCH HIGHER THAN 30 POPS FOR ALL
LOCATIONS. WILL UPDATE THE ZONES TO REFLECT THIS. WILL ALSO REMOVE
HEAVY RAIN THREAT GIVEN SPARSE COVERAGE. AMPLE LOW LEVEL MOISTURE
AND DIMINISHING WINDS WILL MAKE FOG AND/OR STRATUS A CONCERN AFTER
MIDNIGHT...ESPECIALLY IF HOLES CAN DEVELOP IN THE MID AND UPPER
LEVEL CLOUDS. WILL CONTINUE TO MENTION AREAS OF FOG IN THE ZONES
AFTER MIDNIGHT AS WELL AS IN THE HWO. LOWS WILL RANGE FROM THE
UPPER 60S NW TO THE LOWER 70S ELSEWHERE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM FRIDAY/...
THE LOWER GREAT LAKES AND OHIO VALLEY REGION WILL BE BETWEEN A
LARGE ANOMALOUS UPR LVL LOW OVER ONTARIO AND A MID LVL SUBTROPICAL
RIDGE OVER THE SRN STATES THROUGH THE SHORT TERM PERIOD. THIS
SETUP WILL ONLY ALLOW AFOREMENTIONED FRONTAL SYSTEM TO MOVE EVER
SO SLOWLY TO SOUTHEAST...EVENTUALLY STALLING NEAR THE OHIO RIVER
BY FRIDAY MORNING AS MID LEVEL FLOW BECOMES ZONAL. THE FRONT WILL
PROVIDE THE FOCUS FOR SHOWERS AND STORMS THROUGH THE PERIOD...BUT
THE TIMING AND AREAL COVERAGE WILL BE PROBLEMATIC AS MODELS ARE
ESSENTIALLY OFFERING DIFFERENT SOLUTIONS. HAVE GONE WITH A
NAM/ECMWF BLEND WHICH IS FORECASTING A SLOWER FRONTAL MOVEMENT. AS
SUCH...THERE IS A HINT OF A FRONTAL WAVE RIPPLING ALONG THE FRONT
ON THURSDAY THROUGH THE HEART OF THE FORECAST AREA. THIS WAVE AND
ANY UPR LVL SUPPORT FROM AN ASSOCIATED DISTURBANCE OR MCV SHOULD
PROVIDE THE BEST CHANCE FOR SHOWERS AND STORMS ALONG AND SOUTHEAST
OF THE LOW. HAVE HIGHEST POPS MAINLY FOR POINTS ALONG AND
SOUTHEAST OF INTERSTATE 71 WITH THE DIURNAL CYCLE PLAYING A ROLE
IN TERMS OF BEST COVERAGE.
LOOKS LIKE WAVE MOVES OFF TO THE NORTHEAST THURSDAY NIGHT...WHICH
SHOULD RESULT IN A DOWN TICK IN SHOWER/THUNDERSTORMS COVERAGE IN
ITS WAKE.
THE AIRMASS WILL BE QUITE MOIST ALONG AND AHEAD OF THE FRONT WITH
PWATS OF 2 INCHES PLUS EXPECTED. IN ADDITION...WARM CLOUD DEPTHS
WILL BE CLOSE TO 4 KM WHICH WOULD FAVOR COLLISION/COALESCENCE
PROCESSES AND THE POTENTIAL FOR HEAVY RAIN. GIVEN THE UNCERTAINTY
IN PLACEMENT OF HEAVIEST RAIN WITH UPCOMING ROUNDS OF SHOWERS AND
STORMS...WILL CONTINUE TO HIGHLIGHT THE HEAVY RAIN THREAT/LOCAL
FLOODING ISSUES IN THE HWO WITH AN EMPHASIS PLACED ACRS THE SRN
CWFA CLOSER TO THE FRONTAL BOUNDARY.
HIGHS ON THURSDAY SHOULD BE HELD DOWN BY CLOUDS AND PCPN...WITH
LOWER TO MID 80S EXPECTED. LOWS THURSDAY NIGHT WILL RANGE FROM THE
MID 60S NW TO THE LOWER 70S SOUTH.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
MAIN FOCUS FOR THE FIRST PART OF THE EXTENDED PERIOD WILL BE A
SURFACE FRONTAL BOUNDARY THAT WILL ORIENT ITSELF ALONG THE OHIO
RIVER FRIDAY MORNING. WITH ZONAL FLOW ALOFT...THIS BOUNDARY WILL
VERY SLOWLY SAG SOUTHWARD THROUGH THE WEEKEND. ONE WAVE OF LOW
PRESSURE RIDING ALONG THE FRONT WILL BE EXITING TO THE NORTHEAST AT
THE START OF THE PERIOD...ONLY TO BE FOLLOWED BY ANOTHER RIPPLE
FRIDAY NIGHT INTO SATURDAY. SOUTHERN PORTIONS OF THE FA WILL SEE THE
GREATEST CHANCE FOR RAIN THROUGH THE WEEKEND AND LATEST
DETERMINISTIC RUNS CONTINUE TO INDICATE PW VALUES IN THE 150 TO 175
PERCENT OF NORMAL RANGE THERE THROUGH FRIDAY NIGHT. WITH SEVERAL
ROUNDS OF SHOWERS AND STORMS IN THE FORECAST...WILL CONTINUE TO
MONITOR THE POSSIBILITY OF SOME LOCALIZED FLOODING ACROSS THE SOUTH.
THE 12Z GFS AND ECMWF HAVE BOTH NUDGED QPF A TAD FURTHER SOUTH
FOR SATURDAY AND SUNDAY THAN THEY HAD IN EARLIER RUNS...SO OPTED TO
LOWER OR TAKE OUT POPS ACROSS THE NORTHERN HALF OF THE FA THROUGH
THE WEEKEND. KEPT CHANCE POPS IN ACROSS THE SOUTH WHILE THE FRONT
LINGERS NEAR THE OHIO RIVER. BY MONDAY A MID LEVEL TROUGH OVER
EASTERN CANADA WILL BEGIN TO AMPLIFY...RESULTING IN NW FLOW OVER THE
OHIO VALLEY BY THE MIDDLE OF NEXT WEEK. MEANWHILE SURFACE HIGH
PRESSURE WILL BUILD OVER THE GREAT LAKES WHICH SHOULD PROVIDE A
PERIOD OF DRIER WEATHER FOR TUESDAY AND WEDNESDAY. TEMPERATURES
THROUGH THE PERIOD WILL REMAIN A FEW DEGREES BELOW NORMAL WITH HIGHS
IN THE UPPER 70S TO LOWER 80S.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
SLOW MOVING COLD FRONT MOVING INTO NW OHIO WILL SLIP INTO CENTRAL
OHIO THIS AFTERNOON AND STALL OUT NEAR THE OHIO RIVER TONIGHT.
SCATTERED STORMS WERE DEVELOPING AHD OF THIS FRONT ACRS PORTIONS
OF CENTRAL AND SRN OHIO WHERE BLYR CAPE WERE APPROACHING 1000
J/KG. HAVE TEMPO MENTION OF STORMS WITH MVFR CONDITIONS AT
KDAY/KCMH AND KLCK WHERE COVERAGE LOOKS BEST.
FOG AND STRATUS IS EXPECTED AGAIN EARLY THIS MORNING IN MOIST
ENVIRONMENT. IFR CIGS/VSBYS ARE POSSIBLE IN ANY LOCATION BUT MORE
LIKELY AT KCVG/KLUK AND KILN.
GENERALLY EXPECT CONDITIONS LIFTING TO MVFR AFTER SUNRISE.
THUNDERSTORM CHANCES CONTINUE TO INCREASE WITH THE FRONT SLIPPING
A LTL FURTHER SOUTH AND BLYR LAYER CAPES OF 1200-1800 J/KG DURG
THE AFTN. HAVE MENTION OF VCTS AND THEN PLACED PREVAILING PRECIP
IN THE TIME FRAME WHEN THREAT APPEARS BEST. HOWEVER...UNCERTAINTY
EXISTS REGARDING TIMING AND PLACEMENT DUE TO MODEL SOLN DIFFERENCES
REGARDING FRONTAL MOVEMENT. GIVEN WESTERLY UPPER LEVEL FLOW WHICH
BACKS SLIGHTLY TONIGHT...PREFER SLOWER MOVEMENT MORE LIKE THE
GFS/ECMWF SOLNS WITH THE NAM APPEARING TO BE TOO FAST.
OUTLOOK...THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE AT TIMES
THROUGH FRIDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...FRANKS/HICKMAN
SHORT TERM...HICKMAN
LONG TERM...KURZ
AVIATION...AR
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
618 PM EDT THU AUG 8 2013
.SYNOPSIS...
MOIST SOUTHERLY FLOW WILL REMAIN ACROSS THE REGION THROUGH SATURDAY
KEEPING CHANCES FOR SHOWERS AND THUNDERSTORMS ENHANCED. A COLD
FRONT WILL MOVE INTO THE AREA FROM THE NORTH LATE ON SATURDAY INTO
SUNDAY MORNING KEEPING RAIN CHANCES ELEVATED THROUGH TUESDAY AS IT
SLOWLY MIGRATES SOUTHWARD. SOUTHERLY FLOW WILL RETURN BY WEDNESDAY
ALLOWING FOR A GRADUAL WARMING TREND AND INCREASING MOISTURE.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF LATE AFTERNOON...COVERAGE OF SHOWER ACTIVITY OVER THE WESTERN
CAROLINAS CONTINUES TO DECREASE...SO THE PRECIP CHANCES WERE WOUND
DOWN ACROSS MOST OF THE AREA. HOWEVER...AREA RADARS SHOW EXTENSIVE
THUNDERSTORM ACTIVITY IN SOUTHEASTERN TN...SO EXPECT SOME RESURGENCE
TO COVERAGE AT LEAST OVER THE SW AND SRN MOUNTAINS. NOT SURE IF THIS
WILL MAKE IT OVER OR AROUND THE MTNS...SO ANOTHER UPDATE MIGHT BE
REQUIRED TO BRING THE PRECIP CHANCE BACK UP OVER PARTS OF NE GEORGIA
AND THE UPSTATE THIS EVENING.
PREVIOUS DISCUSSION...
AS OF 235 PM EDT...THE FORECAST AREA WILL REMAIN IN MOSTLY ZONAL
FLOW BETWEEN SHALLOW HIGH PRESSURE ACROSS THE DEEP SOUTH AND A
BETTER BELT OF WESTERLIES FROM THE OH VALLEY NORTHWARD THROUGH THE
NEAR TERM. WEAK MID AND UPPER VORTICITY LOBES WILL CROSS THE AREA
THROUGH THE PERIOD...WITH SLIGHTLY BETTER FORCING AFFECTING THE NRN
TIER. AT LOWER LEVELS...S TO SW FLOW IN THE BOUNDARY LAYER WILL
CONTINUE TO TRIGGER SHOWERS AND TSTMS IN A MOSTLY DIURNAL PATTERN IN
THE MOST SOUTHERLY UPSLOPE FLOW PRONE LOCATIONS. INSTABILITY HAS
STAYED SOMEWHAT LIMITED DUE TO THE CLOUD COVER AND MOIST PROFILES
TODAY...SO ANY SEVERE TSTM THREAT WILL BE QUITE MARGINAL.
HOWEVER...HIGH PRECIPITABLE WATER VALUES AROUND 2 INCHES IN MORNING
RAOBS AND MODEL SOUNDINGS...WARM CLOUD LAYERS OF GENERALLY 12 TO 13
KFT...AND MBE VECTORS LESS THAN 10 KT WILL KEEP THE ISOLATED FLASH
FLOOD THREAT FAIRLY HIGH WITH ANY TRAINING CELLS. WE PLAN ON NO
CURRENT CHANGES TO THE FLASH FLOOD WATCH SINCE THE CURRENT WATCH
AREA APPEARS TO STILL HAVE THE BEST OVERLAP OF FOCUSED...TRAINING
POTENTIAL ALONG WITH SATURATED ANTECEDENT CONDITIONS.
DESPITE THE ABUNDANT...LINGERING MOISTURE AND WEAK...SPORADIC UPPER
WAVE ENERGY OVERNIGHT PRECIP COVERAGE SHOULD GRADUALLY TREND DOWN
OVERNIGHT AS THE MODEL PROFILES QUICKLY DEVELOP A LARGE NEGATIVE
BOUYANCY AREA FROM MID EVENING ONWARD. ANTICIPATE LOW CLOUDS AND FOG
DEVELOPING TOWARD DAYBREAK...BUT THE FOG SHOULD NOT BE PARTICULARLY
DENSE OUTSIDE OF ANY MOUNTAIN RIVER VALLEYS. EXPECT MIN TEMPS ABOVE
GUIDANCE GIVEN THE CLOUD COVER AND RECENT PERFORMANCE.
PROFILES REMAIN MOIST FRI WITH MODEL PWAT VALUES AROUND 2 INCHES
ALONG WITH FAIRLY WEAK STEERING FLOW. IT IS POSSIBLE THAT 850 MB
FLOW MAY BECOME A BIT MORE WESTERLY...AND THIS SLIGHT VEERING COULD
RELIEVE SOME OF THE SRLY UPSLOPE AREAS OF THE BEST CONVECTIVE PRECIP
FOCUS. HOWEVER...BL WINDS MAY CONTINUE MORE SW THROUGH FRI AFTN.
ONCE AGAIN...AN ISOLATED FLASH FLOOD THREAT WILL CONTINUE. WILL
FEATURE MAX TEMPS BELOW GUIDANCE GIVEN THE CLOUD COVER AND RECENT
VERIFICATION.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 200 PM EDT...CHANCES FOR SHOWERS AND THUNDERSTORMS WILL TAPER
OFF SLIGHTLY DURING THE OVERNIGHT HOURS FRIDAY EVENING AS DAYTIME
HEATING FADES. THUS...LOWERED POPS TO CHANCE LEVELS ACROSS THE AREA
WITH THE HIGHEST SOLID CHANCE POPS BEING ALONG THE HIGH TERRAIN
WHERE UPSLOPE FLOW WILL PROLONG THE ACTIVITY. FOR SATURDAY...WEAK
COLD FRONT ASSOCIATED WITH UPPER LOW LOCATED OVER EASTERN CANADA
WILL BE ORIENTED FROM WEST TO EAST AND MOVING SLOWLY OUT OF THE OHIO
VALLEY AND INTO THE TENNESSEE VALLEY REGION. MEANWHILE...DEEP
MOISTURE FETCH WILL REMAIN IN PLACE ACROSS THE SOUTHEASTERN UNITED
STATES AS BERMUDA HIGH DOMINATE THE FLOW. MODEL GUIDANCE REMAINS IN
GOOD AGREEMENT WITH REGARDS TO A DIURNAL TYPE TREND TO THE
CONVECTION ON SATURDAY. THERE WILL BE ENHANCEMENTS OVER THE HIGH
TERRAIN AS LOW LEVEL FLOW CONTINUES TO PROMOTE UPSLOPE COMPONENTS.
THEREFORE...HIGHLIGHTED SOLID CHANCE POPS ACROSS THE UPSTATE AND
NORTHEAST GA REGIONS WITH LIKELY POPS PREVAILING ACROSS MUCH OF
WESTERN NC. AS THE ABOVE MENTIONED SURFACE FRONT MOVES CLOSER TO
THE REGION...WOULD NOT BE SURPRISED TO SEE SOME ADDITIONAL
ENHANCEMENT ALONG THE BOUNDARY ACROSS NORTHWEST NC. DUE TO THE
AMOUNT OF ABUNDANT MOISTURE IN THE PROFILE YIELDING ABOVE CLIMO
PRECIPITABLE WATERS...THINK THE MAIN THREAT SATURDAY WILL BE
LOCALIZED HEAVY RAINFALL AS STEERING FLOW REMAINS WEAK.
MUCH OF THE SAME FOR SUNDAY AS QUASI STATIONARY SURFACE BOUNDARY
REMAINS DRAPED ACROSS THE SOUTHERN APPALACHIANS. MOISTURE CONTENT
THROUGH THE PROFILE WILL REMAIN HIGH...YET SLIGHTLY LESS THAN
PREVIOUS DAYS AS LOW LEVEL FLOW SHIFTS MORE WESTERLY. WITH THAT
BEING SAID...KEPT NEARLY THE SAME POP FORECAST AS SATURDAY WITH
LIKELY POPS RESIDING ACROSS MUCH OF WESTERN NC AND CHANCE POPS
ELSEWHERE. DUE TO SLIGHTLY LESS SKY COVER ACROSS THE REGION ON
SUNDAY...WOULD NOT BE SURPRISED TO SEE GREATER INSTABILITY AS MORE
SUNSHINE ALLOWS FOR ADDITIONAL HEATING. THUS...SOME SCATTERED
AFTERNOON THUNDERSTORMS ARE POSSIBLE. TEMPERATURES THROUGH THE
SHORT TERM PERIOD WILL REMAIN AT OR SLIGHTLY BELOW NORMAL.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 230 PM EDT...SURFACE FRONTAL BOUNDARY WILL MOVE SOUTHWARD INTO
THE LOW COUNTRY AND DRAPE WESTWARD ACROSS THE MID GULF COAST
STATES ON MONDAY. MEANWHILE...SLIGHTLY DRIER AIR WILL WORK ITS WAY
IN ACROSS THE REGION FOR THE START OF THE WORK WEEK.
HOWEVER...WESTERLY LOW LEVEL FLOW WILL ALLOW FOR ENHANCED UPSLOPE
CONVECTION ACROSS THE HIGH TERRAIN ON MONDAY WHERE LIKELY POPS WILL
PREVAIL. THE ABOVE MENTIONED BOUNDARY WILL PROVIDE A FOCUS FOR
THUNDERSTORM ACTIVITY ACROSS THE MIDLANDS AND PERHAPS INTO THE
UPSTATE OF SC THROUGH MIDWEEK. KEPT ABOVE CLIMO POPS IN THE
FORECAST THROUGH THE REMAINDER OF THE PERIOD AS SOUTHERLY FLOW
GRADUALLY RETURNS ALLOWING FOR INCREASING MOISTURE ACROSS THE AREA.
TEMPERATURES THROUGH THE EXTENDED PERIOD WILL REMAIN A FEW DEGREES
BELOW NORMAL.
&&
.AVIATION /22Z THURSDAY THROUGH TUESDAY/...
AT KCLT...THE LATEST HRRR MODEL RUN HAS CAPTURED THE LINE OF WEAK
CONVECTION W OF THE AIRFIELD THIS AFTN. STILL NOT SEEING ANY
LIGHTNING WITH THIS...BUT TEMPO TSRA WAS MOVED UP TO 19Z TO ACCOUNT
FOR EARLIER TRIGGERING AS THIS ACTIVITY MOVES E. GIVEN THE LOW
LCL/CCL...CIGS WILL LIKELY REMAIN LOWER VFR AND QUICKLY TOGGLE OVER
INTO MVFR WITH ANY SHOWERS AT THE AIRFIELD. CANNOT RULE OUT SOME
BRIEF IFR VSBY WITH ANY HEAVIER DOWNPOURS BUT CONFIDENCE IS TOO LOW
TO FORECAST THAT. ANTICIPATE COVERAGE TO DWINDLE GRADUALLY LATE THIS
EVENING THROUGH THE OVERNIGHT...WITH RESONABLE CHANCES OF AT LEAST
MVFR RESTRICTIONS EARLY FRI GIVEN THE LOW LEVEL MOISTURE. WILL
REINTRODUCE VCSH ALONG WITH GRADUAL IMPROVEMENT INTO VFR LATE FRI
MORNING AND WILL HOLD OFF ON ANY FRI THUNDER POTENTIAL UNTIL AFTER
18Z. WINDS SHOULD REMAIN SW AT LESS THAN 10 KT THROUGH THE
PERIOD...ASIDE FROM ANY TSTMS.
ELSEWHERE...COVERAGE OF WEAK CONVECTION IS GRADUALLY FILLING IN
ACROSS THE REGION THIS AFTN. HAVE STARTED TEMPO TSRA EARLIEST AT
KAVL...BUT WILL NEED SOME MENTION BY ABOUT 19Z AT THE FOOTHILL TAF
SITES AS WELL. EXPECT CIGS TO ALTERNATE BETWEEN MVFR AND VFR THROUGH
LATE DAY...WITH BRIEF IFR CONDITIONS POSSIBLE WITH ANY HEAVY
DOWNPOURS. COVERAGE WILL GRADUALLY DIMINISH TONIGHT...WITH A RETURN
OF MVFR CIGS LIKELY BY DAYBREAK AT THE UPSTATE TAFS...IFR AT KAVL BY
09Z...AND TEMPO IFR AT KHKY AT TIMES. EXPECT SLOW IMPROVEMENT
THROUGH LATE MORNING WITH VCSH RETURNING TO THE FORECAST. WILL ONLY
MENTION PROB30 FOR TSRA AT KAVL PRIOR TO 18Z GIVEN THE EARLIEST MTN
ONSET WITH TERRAIN UPSLOPE. EXPECT MAINLY LIGHT SW WINDS THROUGH THE
PERIOD...EXCEPT VRB NEAR TSTMS.
OUTLOOK...DEEP MOISTURE AND DAILY SHOWER/TSTM TRIGGERING WILL
CONTINUE THROUGH THE WEEKEND. IFR TO MVFR RESTRICTIONS LOOK LIKELY
LATE EACH NIGHT/EARLY EACH MORNING...WITH ADDITIONAL RESTRICTIONS
UNDER ANY CONVECTION. CONDITIONS MAY STAY UNSETTLED THROUGH EARLY
NEXT WEEK DEPENDING ON THE SWD PROGRESS OF A WEAK FRONT THROUGH THE
AREA.
CONFIDENCE TABLE...
22-04Z 04-10Z 10-16Z 16-22Z
KCLT HIGH 100% HIGH 91% HIGH 88% HIGH 100%
KGSP HIGH 93% MED 61% HIGH 81% HIGH 100%
KAVL MED 76% MED 66% MED 70% HIGH 89%
KHKY HIGH 81% MED 76% MED 75% HIGH 100%
KGMU HIGH 86% MED 63% HIGH 81% HIGH 94%
KAND HIGH 100% HIGH 95% HIGH 90% HIGH 83%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...FLASH FLOOD WATCH UNTIL 6 AM EDT FRIDAY FOR GAZ010-017-018-026-
028-029.
NC...FLASH FLOOD WATCH UNTIL 6 AM EDT FRIDAY FOR NCZ062>065-509-510.
SC...FLASH FLOOD WATCH UNTIL 6 AM EDT FRIDAY FOR SCZ001>007-010>012-
019.
&&
$$
SYNOPSIS...CDG
NEAR TERM...HG/PM
SHORT TERM...CDG
LONG TERM...CDG
AVIATION...HG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
241 PM EDT THU AUG 8 2013
.SYNOPSIS...
MOIST SOUTHERLY FLOW WILL REMAIN ACROSS THE REGION THROUGH SATURDAY
KEEPING CHANCES FOR SHOWERS AND THUNDERSTORMS ENHANCED. A COLD
FRONT WILL MOVE INTO THE AREA FROM THE NORTH LATE ON SATURDAY INTO
SUNDAY MORNING KEEPING RAIN CHANCES ELEVATED THROUGH TUESDAY AS IT
SLOWLY MIGRATES SOUTHWARD. SOUTHERLY FLOW WILL RETURN BY WEDNESDAY
ALLOWING FOR A GRADUAL WARMING TREND AND INCREASING MOISTURE.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF 235 PM EDT...THE FORECAST AREA WILL REMAIN IN MOSTLY ZONAL
FLOW BETWEEN SHALLOW HIGH PRESSURE ACROSS THE DEEP SOUTH AND A
BETTER BELT OF WESTERLIES FROM THE OH VALLEY NORTHWARD THROUGH THE
NEAR TERM. WEAK MID AND UPPER VORTICITY LOBES WILL CROSS THE AREA
THROUGH THE PERIOD...WITH SLIGHTLY BETTER FORCING AFFECTING THE NRN
TIER. AT LOWER LEVELS...S TO SW FLOW IN THE BOUNDARY LAYER WILL
CONTINUE TO TRIGGER SHOWERS AND TSTMS IN A MOSTLY DIURNAL PATTERN IN
THE MOST SOUTHERLY UPSLOPE FLOW PRONE LOCATIONS. INSTABILITY HAS
STAYED SOMEWHAT LIMITED DUE TO THE CLOUD COVER AND MOIST PROFILES
TODAY...SO ANY SEVERE TSTM THREAT WILL BE QUITE MARGINAL.
HOWEVER...HIGH PRECIPITABLE WATER VALUES AROUND 2 INCHES IN MORNING
RAOBS AND MODEL SOUNDINGS...WARM CLOUD LAYERS OF GENERALLY 12 TO 13
KFT...AND MBE VECTORS LESS THAN 10 KT WILL KEEP THE ISOLATED FLASH
FLOOD THREAT FAIRLY HIGH WITH ANY TRAINING CELLS. WE PLAN ON NO
CURRENT CHANGES TO THE FLASH FLOOD WATCH SINCE THE CURRENT WATCH
AREA APPEARS TO STILL HAVE THE BEST OVERLAP OF FOCUSED...TRAINING
POTENTIAL ALONG WITH SATURATED ANTECEDENT CONDITIONS.
DESPITE THE ABUNDANT...LINGERING MOISTURE AND WEAK...SPORADIC UPPER
WAVE ENERGY OVERNIGHT PRECIP COVERAGE SHOULD GRADUALLY TREND DOWN
OVERNIGHT AS THE MODEL PROFILES QUICKLY DEVELOP A LARGE NEGATIVE
BOUYANCY AREA FROM MID EVENING ONWARD. ANTICIPATE LOW CLOUDS AND FOG
DEVELOPING TOWARD DAYBREAK...BUT THE FOG SHOULD NOT BE PARTICULARLY
DENSE OUTSIDE OF ANY MOUNTAIN RIVER VALLEYS. EXPECT MIN TEMPS ABOVE
GUIDANCE GIVEN THE CLOUD COVER AND RECENT PERFORMANCE.
PROFILES REMAIN MOIST FRI WITH MODEL PWAT VALUES AROUND 2 INCHES
ALONG WITH FAIRLY WEAK STEERING FLOW. IT IS POSSIBLE THAT 850 MB
FLOW MAY BECOME A BIT MORE WESTERLY...AND THIS SLIGHT VEERING COULD
RELIEVE SOME OF THE SRLY UPSLOPE AREAS OF THE BEST CONVECTIVE PRECIP
FOCUS. HOWEVER...BL WINDS MAY CONTINUE MORE SW THROUGH FRI AFTN.
ONCE AGAIN...AN ISOLATED FLASH FLOOD THREAT WILL CONTINUE. WILL
FEATURE MAX TEMPS BELOW GUIDANCE GIVEN THE CLOUD COVER AND RECENT
VERIFICATION.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 200 PM EDT...CHANCES FOR SHOWERS AND THUNDERSTORMS WILL TAPER
OFF SLIGHTLY DURING THE OVERNIGHT HOURS FRIDAY EVENING AS DAYTIME
HEATING FADES. THUS...LOWERED POPS TO CHANCE LEVELS ACROSS THE AREA
WITH THE HIGHEST SOLID CHANCE POPS BEING ALONG THE HIGH TERRAIN
WHERE UPSLOPE FLOW WILL PROLONG THE ACTIVITY. FOR SATURDAY...WEAK
COLD FRONT ASSOCIATED WITH UPPER LOW LOCATED OVER EASTERN CANADA
WILL BE ORIENTED FROM WEST TO EAST AND MOVING SLOWLY OUT OF THE OHIO
VALLEY AND INTO THE TENNESSEE VALLEY REGION. MEANWHILE...DEEP
MOISTURE FETCH WILL REMAIN IN PLACE ACROSS THE SOUTHEASTERN UNITED
STATES AS BERMUDA HIGH DOMINATE THE FLOW. MODEL GUIDANCE REMAINS IN
GOOD AGREEMENT WITH REGARDS TO A DIURNAL TYPE TREND TO THE
CONVECTION ON SATURDAY. THERE WILL BE ENHANCEMENTS OVER THE HIGH
TERRAIN AS LOW LEVEL FLOW CONTINUES TO PROMOTE UPSLOPE COMPONENTS.
THEREFORE...HIGHLIGHTED SOLID CHANCE POPS ACROSS THE UPSTATE AND
NORTHEAST GA REGIONS WITH LIKELY POPS PREVAILING ACROSS MUCH OF
WESTERN NC. AS THE ABOVE MENTIONED SURFACE FRONT MOVES CLOSER TO
THE REGION...WOULD NOT BE SURPRISED TO SEE SOME ADDITIONAL
ENHANCEMENT ALONG THE BOUNDARY ACROSS NORTHWEST NC. DUE TO THE
AMOUNT OF ABUNDANT MOISTURE IN THE PROFILE YIELDING ABOVE CLIMO
PRECIPITABLE WATERS...THINK THE MAIN THREAT SATURDAY WILL BE
LOCALIZED HEAVY RAINFALL AS STEERING FLOW REMAINS WEAK.
MUCH OF THE SAME FOR SUNDAY AS QUASI STATIONARY SURFACE BOUNDARY
REMAINS DRAPED ACROSS THE SOUTHERN APPALACHIANS. MOISTURE CONTENT
THROUGH THE PROFILE WILL REMAIN HIGH...YET SLIGHTLY LESS THAN
PREVIOUS DAYS AS LOW LEVEL FLOW SHIFTS MORE WESTERLY. WITH THAT
BEING SAID...KEPT NEARLY THE SAME POP FORECAST AS SATURDAY WITH
LIKELY POPS RESIDING ACROSS MUCH OF WESTERN NC AND CHANCE POPS
ELSEWHERE. DUE TO SLIGHTLY LESS SKY COVER ACROSS THE REGION ON
SUNDAY...WOULD NOT BE SURPRISED TO SEE GREATER INSTABILITY AS MORE
SUNSHINE ALLOWS FOR ADDITIONAL HEATING. THUS...SOME SCATTERED
AFTERNOON THUNDERSTORMS ARE POSSIBLE. TEMPERATURES THROUGH THE
SHORT TERM PERIOD WILL REMAIN AT OR SLIGHTLY BELOW NORMAL.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 230 PM EDT...SURFACE FRONTAL BOUNDARY WILL MOVE SOUTHWARD INTO
THE LOW COUNTRY AND DRAPE WESTWARD ACROSS THE MID GULF COAST
STATES ON MONDAY. MEANWHILE...SLIGHTLY DRIER AIR WILL WORK ITS WAY
IN ACROSS THE REGION FOR THE START OF THE WORK WEEK.
HOWEVER...WESTERLY LOW LEVEL FLOW WILL ALLOW FOR ENHANCED UPSLOPE
CONVECTION ACROSS THE HIGH TERRAIN ON MONDAY WHERE LIKELY POPS WILL
PREVAIL. THE ABOVE MENTIONED BOUNDARY WILL PROVIDE A FOCUS FOR
THUNDERSTORM ACTIVITY ACROSS THE MIDLANDS AND PERHAPS INTO THE
UPSTATE OF SC THROUGH MIDWEEK. KEPT ABOVE CLIMO POPS IN THE
FORECAST THROUGH THE REMAINDER OF THE PERIOD AS SOUTHERLY FLOW
GRADUALLY RETURNS ALLOWING FOR INCREASING MOISTURE ACROSS THE AREA.
TEMPERATURES THROUGH THE EXTENDED PERIOD WILL REMAIN A FEW DEGREES
BELOW NORMAL.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
AT KCLT...THE LATEST HRRR MODEL RUN HAS CAPTURED THE LINE OF WEAK
CONVECTION W OF THE AIRFIELD THIS AFTN. STILL NOT SEEING ANY
LIGHTNING WITH THIS...BUT TEMPO TSRA WAS MOVED UP TO 19Z TO ACCOUNT
FOR EARLIER TRIGGERING AS THIS ACTIVITY MOVES E. GIVEN THE LOW
LCL/CCL...CIGS WILL LIKELY REMAIN LOWER VFR AND QUICKLY TOGGLE OVER
INTO MVFR WITH ANY SHOWERS AT THE AIRFIELD. CANNOT RULE OUT SOME
BRIEF IFR VSBY WITH ANY HEAVIER DOWNPOURS BUT CONFIDENCE IS TOO LOW
TO FORECAST THAT. ANTICIPATE COVERAGE TO DWINDLE GRADUALLY LATE THIS
EVENING THROUGH THE OVERNIGHT...WITH RESONABLE CHANCES OF AT LEAST
MVFR RESTRICTIONS EARLY FRI GIVEN THE LOW LEVEL MOISTURE. WILL
REINTRODUCE VCSH ALONG WITH GRADUAL IMPROVEMENT INTO VFR LATE FRI
MORNING AND WILL HOLD OFF ON ANY FRI THUNDER POTENTIAL UNTIL AFTER
18Z. WINDS SHOULD REMAIN SW AT LESS THAN 10 KT THROUGH THE
PERIOD...ASIDE FROM ANY TSTMS.
ELSEWHERE...COVERAGE OF WEAK CONVECTION IS GRADUALLY FILLING IN
ACROSS THE REGION THIS AFTN. HAVE STARTED TEMPO TSRA EARLIEST AT
KAVL...BUT WILL NEED SOME MENTION BY ABOUT 19Z AT THE FOOTHILL TAF
SITES AS WELL. EXPECT CIGS TO ALTERNATE BETWEEN MVFR AND VFR THROUGH
LATE DAY...WITH BRIEF IFR CONDITIONS POSSIBLE WITH ANY HEAVY
DOWNPOURS. COVERAGE WILL GRADUALLY DIMINISH TONIGHT...WITH A RETURN
OF MVFR CIGS LIKELY BY DAYBREAK AT THE UPSTATE TAFS...IFR AT KAVL BY
09Z...AND TEMPO IFR AT KHKY AT TIMES. EXPECT SLOW IMPROVEMENT
THROUGH LATE MORNING WITH VCSH RETURNING TO THE FORECAST. WILL ONLY
MENTION PROB30 FOR TSRA AT KAVL PRIOR TO 18Z GIVEN THE EARLIEST MTN
ONSET WITH TERRAIN UPSLOPE. EXPECT MAINLY LIGHT SW WINDS THROUGH THE
PERIOD...EXCEPT VRB NEAR TSTMS.
OUTLOOK...DEEP MOISTURE AND DAILY SHOWER/TSTM TRIGGERING WILL
CONTINUE THROUGH THE WEEKEND. IFR TO MVFR RESTRICTIONS LOOK LIKELY
LATE EACH NIGHT/EARLY EACH MORNING...WITH ADDITIONAL RESTRICTIONS
UNDER ANY CONVECTION. CONDITIONS MAY STAY UNSETTLED THROUGH EARLY
NEXT WEEK DEPENDING ON THE SWD PROGRESS OF A WEAK FRONT THROUGH THE
AREA.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 100% HIGH 100% MED 76% MED 79%
KGSP HIGH 100% MED 78% LOW 58% MED 75%
KAVL MED 76% MED 62% MED 67% MED 69%
KHKY MED 74% MED 64% MED 68% HIGH 87%
KGMU HIGH 97% MED 71% LOW 58% MED 70%
KAND HIGH 97% HIGH 100% MED 75% MED 65%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR GAZ010-017-018-026-
028-029.
NC...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR NCZ062>065-509-510.
SC...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR SCZ001>007-010>012-
019.
&&
$$
SYNOPSIS...CDG
NEAR TERM...HG
SHORT TERM...CDG
LONG TERM...CDG
AVIATION...HG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
219 PM EDT THU AUG 8 2013
.SYNOPSIS...
MOIST HIGH PRESSURE WILL REMAIN OVER THE AREA THROUGH SATURDAY. A
WEAK COLD FRONT WILL ARRIVE FROM THE NORTH ON SUNDAY. THIS FRONT
WILL SLOWLY CROSS THE AREA THROUGH TUESDAY...BEFORE MOVING SOUTH OF
THE AREA ON WEDNESDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF 215 PM EDT...THE FORECAST AREA WILL GENERALLY REMAIN IN ZONAL
FLOW BETWEEN SHALLOW HIGH PRESSURE ACROSS THE DEEP SOUTH AND A
BETTER BELT OF WESTERLIES FROM THE OH VALLEY NORTHWARD THROUGH THE
NEAR TERM. WEAK MID AND UPPER VORTICITY LOBES WILL CROSS THE AREA
THROUGH THE PERIOD...WITH SLIGHTLY BETTER FORCING AFFECTING THE NRN
TIER. AT LOWER LEVELS...S TO SW FLOW IN THE BOUNDARY LAYER WILL
CONTINUE TO TRIGGER SHOWERS AND TSTMS IN A MOSTLY DIURNAL PATTERN IN
THE MOST SOUTHERLY UPSLOPE FLOW PRONE LOCATIONS. INSTABILITY HAS
STAYED SOMEWHAT LIMITED DUE TO THE CLOUD COVER AND MOIST PROFILES
TODAY...SO ANY SEVERE TSTM THREAT WILL BE QUITE MARGINAL.
HOWEVER...HIGH PRECIPITABLE WATER VALUES AROUND 2 INCHES IN MORNING
RAOBS AND MODEL SOUNDINGS...WARM CLOUD LAYERS OF GENERALLY 12 TO 13
KFT...AND MBE VECTORS LESS THAN 10 KT WILL KEEP THE ISOLATED FLASH
FLOOD THREAT FAIRLY HIGH WITH ANY TRAINING CELLS. WE PLAN ON NO
CURRENT CHANGES TO THE FLASH FLOOD WATCH SINCE THE CURRENT WATCH
AREA APPEARS TO STILL HAVE THE BEST OVERLAP OF FOCUSED...TRAINING
POTENTIAL ALONG WITH SATURATED ANTECEDENT CONDITIONS.
DESPITE THE ABUNDANT...LINGERING MOISTURE AND WEAK...SPORADIC UPPER
WAVE ENERGY OVERNIGHT PRECIP COVERAGE SHOULD GRADUALLY TREND DOWN
OVERNIGHT AS THE MODEL PROFILES QUICKLY DEVELOP A LARGE NEGATIVE
BOUYANCY AREA FROM MID EVENING ONWARD. ANTICIPATE LOW CLOUDS AND FOG
DEVELOPING TOWARD DAYBREAK...BUT THE FOG SHOULD NOT BE PARTICULARLY
DENSE OUTSIDE OF ANY MOUNTAIN RIVER VALLEYS. EXPECT MIN TEMPS ABOVE
GUIDANCE GIVEN THE CLOUD COVER AND RECENT PERFORMANCE.
PROFILES REMAIN MOIST FRI WITH MODEL PWAT VALUES AROUND 2 INCHES
ALONG WITH FAIRLY WEAK STEERING FLOW. IT IS POSSIBLE THAT 850 MB
FLOW MAY BECOME A BIT MORE WESTERLY...AND THIS SLIGHT VEERING COULD
RELIEVE SOME OF THE SRLY UPSLOPE AREAS OF THE BEST CONVECTIVE PRECIP
FOCUS. HOWEVER...BL WINDS MAY CONTINUE MORE SW THROUGH FRI AFTN.
ONCE AGAIN...AN ISOLATED FLASH FLOOD THREAT WILL CONTINUE. WILL
FEATURE MAX TEMPS BELOW GUIDANCE GIVEN THE CLOUD COVER AND RECENT
VERIFICATION.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
AS OF 200 PM EDT...CHANCES FOR SHOWERS AND THUNDERSTORMS WILL TAPER
OFF SLIGHTLY DURING THE OVERNIGHT HOURS FRIDAY EVENING AS DAYTIME
HEATING FADES. THUS...LOWERED POPS TO CHANCE LEVELS ACROSS THE AREA
WITH THE HIGHEST SOLID CHANCE POPS BEING ALONG THE HIGH TERRAIN
WHERE UPSLOPE FLOW WILL PROLONG THE ACTIVITY. FOR SATURDAY...WEAK
COLD FRONT ASSOCIATED WITH UPPER LOW LOCATED OVER EASTERN CANADA
WILL BE ORIENTED FROM WEST TO EAST AND MOVING SLOWLY OUT OF THE OHIO
VALLEY AND INTO THE TENNESSEE VALLEY REGION. MEANWHILE...DEEP
MOISTURE FETCH WILL REMAIN IN PLACE ACROSS THE SOUTHEASTERN UNITED
STATES AS BERMUDA HIGH DOMINATE THE FLOW. MODEL GUIDANCE REMAINS IN
GOOD AGREEMENT WITH REGARDS TO A DIURNAL TYPE TREND TO THE
CONVECTION ON SATURDAY. THERE WILL BE ENHANCEMENTS OVER THE HIGH
TERRAIN AS LOW LEVEL FLOW CONTINUES TO PROMOTE UPSLOPE COMPONENTS.
THEREFORE...HIGHLIGHTED SOLID CHANCE POPS ACROSS THE UPSTATE AND
NORTHEAST GA REGIONS WITH LIKELY POPS PREVAILING ACROSS MUCH OF
WESTERN NC. AS THE ABOVE MENTIONED SURFACE FRONT MOVES CLOSER TO
THE REGION...WOULD NOT BE SURPRISED TO SEE SOME ADDITIONAL
ENHANCEMENT ALONG THE BOUNDARY ACROSS NORTHWEST NC. DUE TO THE
AMOUNT OF ABUNDANT MOISTURE IN THE PROFILE YIELDING ABOVE CLIMO
PRECIPITABLE WATERS...THINK THE MAIN THREAT SATURDAY WILL BE
LOCALIZED HEAVY RAINFALL AS STEERING FLOW REMAINS WEAK.
MUCH OF THE SAME FOR SUNDAY AS QUASI STATIONARY SURFACE BOUNDARY
REMAINS DRAPED ACROSS THE SOUTHERN APPALACHIANS. MOISTURE CONTENT
THROUGH THE PROFILE WILL REMAIN HIGH...YET SLIGHTLY LESS THAN
PREVIOUS DAYS AS LOW LEVEL FLOW SHIFTS MORE WESTERLY. WITH THAT
BEING SAID...KEPT NEARLY THE SAME POP FORECAST AS SATURDAY WITH
LIKELY POPS RESIDING ACROSS MUCH OF WESTERN NC AND CHANCE POPS
ELSEWHERE. DUE TO SLIGHTLY LESS SKY COVER ACROSS THE REGION ON
SUNDAY...WOULD NOT BE SURPRISED TO SEE GREATER INSTABILITY AS MORE
SUNSHINE ALLOWS FOR ADDITIONAL HEATING. THUS...SOME SCATTERED
AFTERNOON THUNDERSTORMS ARE POSSIBLE. TEMPERATURES THROUGH THE
SHORT TERM PERIOD WILL REMAIN AT OR SLIGHTLY BELOW NORMAL.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
AT 230 AM EDT THURSDAY...AN UPPER TROUGH WILL AMPLIFY ALONG THE EAST
COAST FROM SUNDAY THROUGH WEDNESDAY. A COLD FRONT WILL DROP VERY
SLOWLY SOUTH INTO THE NORTHERN PORTION OF THE AREA ON SUNDAY...
CROSSING MUCH OF WESTERN NC ON MONDAY...THE INTERSTATE 85 CORRIDOR
TUESDAY...AND FINALLY MOVING SOUTH OF THE AREA ON WEDNESDAY.
ALTHOUGH THIS BOUNDARY WILL SERVE AS A FOCUSING MECHANISM FOR
PRECIPITATION...SOUTHERLY INFLOW AHEAD OF THE FRONT IS EXPECTED TO
DECREASE BASED ON A REORIENTATION OF THE SURFACE RIDGE TO THE SOUTH.
UPSLOPE WILL BE LIMITED TO THE TN BORDER AREA TO BEGIN WITH AS LOW
LEVEL WINDS WILL BE WESTERLY...AND WILL DIMINISH IN THE LEE OF THE
MOUNTAINS AS THE FRONT SETTLES SOUTH AND WINDS VEER MORE TO THE
NORTHWEST. POPS WILL REMAIN ABOVE CLIMATOLOGY...AND WITH SOME
UNCERTAINTY AS TO THE TIMING OF THE FRONT...POPS WILL BE ALLOWED TO
REMAIN INTO WEDNESDAY. TEMPERATURES WILL DECREASE AS HEIGHTS FALL
ALOFT...BUT THE DIURNAL RANGE WILL REMAIN LIMITED DUE TO CLOUDS AND
MOISTURE.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AT KCLT...THE LATEST HRRR MODEL RUN HAS CAPTURED THE LINE OF WEAK
CONVECTION WEST OF THE AIRFIELD EARLY THIS AFTN. STILL NOT SEEING
ANY LIGHTNING WITH THIS...BUT HAVE MOVED THE TEMPO TSRA UP TO 19Z TO
ACCOUNT FOR EARLIER TRIGGERING AS THIS ACTIVITY MOVES EAST. GIVEN
THE LOW LCL/CCL...CIGS WILL LIKELY REMAIN LOWER VFR AND QUICKLY
TOGGLE OVER INTO MVFR WITH ANY SHOWERS AT THE AIRFIELD. CANNOT RULE
OUT SOME BRIEF IFR VSBY WITH ANY HEAVIER DOWNPOURS BUT CONFIDENCE IS
TOO LOW TO FORECAST THAT. ANTICIPATE COVERAGE TO DWINDLE GRADUALLY
LATE THIS EVENING THROUGH THE OVERNIGHT...WITH RESONABLE CHANCES OF
AT LEAST MVFR RESTRICTIONS EARLY FRI GIVEN THE LOW LEVEL MOISTURE.
WILL REINTRODUCE VCSH ALONG WITH GRADUAL IMPROVEMENT INTO VFR LATE
FRI MORNING AND WILL HOLD OFF ON ANY FRI THUNDER POTENTIAL UNTIL
AFTER 18Z. WINDS SHOULD REMAIN SW AT LESS THAN 10 KT THROUGH THE
PERIOD...ASIDE FROM ANY TSTMS.
ELSEWHERE...COVERAGE OF WEAK CONVECTION IS GRADUALLY FILLING IN
ACROSS THE REGION THIS AFTN. HAVE STARTED TEMPO TSRA EARLIEST AT
KAVL...BUT WILL NEED SOME MENTION BY ABOUT 19Z AT THE FOOTHILL TAF
SITES AS WELL. EXPECT CIGS TO ALTERNATE BETWEEN MVFR AND VFR THROUGH
LATE DAY...WITH BRIEF IFR CONDITIONS POSSIBLE WITH ANY HEAVY
DOWNPOURS. COVERAGE WILL GRADUALLY DIMINISH TONIGHT...WITH A RETURN
OF MVFR CIGS LIKELY BY DAYBREAK AT THE UPSTATE TAFS...IFR AT KAVL BY
09Z...AND TEMPO IFR AT KHKY AT TIMES. EXPECT SLOW IMPROVEMENT
THROUGH LATE MORNING WITH VCSH RETURNING TO THE FORECAST. WILL ONLY
MENTION PROB30 FOR TSRA AT KAVL PRIOR TO 18Z GIVEN THE EARLIEST MTN
ONSET WITH TERRAIN UPSLOPE. EXPECT MAINLY LIGHT SW WINDS THROUGH THE
PERIOD...EXCEPT VRB NEAR TSTMS.
OUTLOOK...DEEP MOISTURE AND DAILY SHOWER/TSTM TRIGGERING WILL
CONTINUE THROUGH THE WEEKEND. IFR TO MVFR RESTRICTIONS LOOK LIKELY
LATE EACH NIGHT/EARLY EACH MORNING...WITH ADDITIONAL RESTRICTIONS
UNDER ANY CONVECTION. CONDITIONS MAY STAY UNSETTLED THROUGH EARLY
NEXT WEEK DEPENDING ON THE SWD PROGRESS OF A WEAK FRONT THROUGH THE
AREA.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 100% HIGH 100% MED 76% MED 79%
KGSP HIGH 100% MED 78% LOW 58% MED 75%
KAVL MED 76% MED 62% MED 67% MED 69%
KHKY MED 74% MED 64% MED 68% HIGH 87%
KGMU HIGH 97% MED 71% LOW 58% MED 70%
KAND HIGH 97% HIGH 100% MED 75% MED 65%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR GAZ010-017-018-026-
028-029.
NC...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR NCZ062>065-509-510.
SC...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR SCZ001>007-010>012-
019.
&&
$$
SYNOPSIS...HG/JAT
NEAR TERM...HG
SHORT TERM...CDG
LONG TERM...JAT
AVIATION...HG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
729 AM EDT THU AUG 8 2013
.SYNOPSIS...
MOIST HIGH PRESSURE WILL REMAIN OVER THE AREA THROUGH SATURDAY. A
WEAK COLD FRONT WILL ARRIVE FROM THE NORTH ON SUNDAY. THIS FRONT
WILL SLOWLY CROSS THE AREA THROUGH TUESDAY...BEFORE MOVING SOUTH OF
THE AREA ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 700 AM EDT THURSDAY...ONLY A FEW LIGHT SHOWERS ARE CURRENTLY
OVER NE GA AND BACK ACROSS THE WRN NC PIEDMONT. POPS HAVE BEEN
TRIMMED TO MATCH THE CURRENT TRENDS. EVERYTHING ELSE LOOKS GOOD
RIGHT NOW.
PREVIOUS DISCUSSION...THE LATEST GSP-WSR88D WIND PROFILER DATA SHOW
NORTHERLY FLOW BETWEEN 9-13 KFT. WHILE AT THE TCLT TDWR THE FLOW AT
THIS LEVEL IS OUT OF THE WSW. THE TROUGH IS ALSO EVIDENT IN THE
REFLECTIVITIES AS PATCHY LIGHT SHOWERS ARE MOVING OUT OF THE NORTH
OVER THE CENTRAL PART OF THE UPSTATE...BUT THEY ARE MOVING FROM THE
SOUTH OVER TOWARD UNION AND GAFFNEY. WHILE THIS IS A WEAK FEATURE IT
MAY BE ENOUGH TO FINALLY KEEP IT DRY THROUGH SUNRISE ON THE BACK
SIDE OF THE TROUGH ACROSS THE BLUE RIDGE. A COUPLE CONVECTION
ALLOWING MODELS FIRE UP HEAVIER SHOWERS AND STORMS EAST OF THE
TROUGH AXIS PRIOR TO SUNRISE HOWEVER. I/M NOT CERTAIN THAT THIS
WON/T HAPPEN...BUT I DOUBT IT AT THIS POINT.
LATER IN THE MORNING THE NAM AND RUC DEVELOP CONVECTION BACK ACROSS
THE BLUE RIDGE AS A STRONGER MID-TROPOSPHERIC TROUGH APPROACHES.
THIS FEATURE IS CURRENTLY EVIDENT ON THE RUC...AND MODESTLY EVIDENT
ON WATER VAPOR IMAGERY...OVER MIDDLE TN AND SW KY. THE SHORT WAVE IS
EXPECTED TO TRIGGER NUMEROUS SHOWERS AND TSTMS OVER MOUNTAINS AND
FOOTHILLS TODAY. EVEN THE PIEDMONT MIGHT GET INTO THE ACT AS THE
LLVL FLOW IS A LITTLE MORE SOUTHWESTERLY TODAY. AS SEVERAL INCHES OF
RAIN HAS FALLEN OVER PARTS OF NE GA...UPSTATE SC AND THE SRN MTNS OF
NC OVER THE PAST 3 DAYS...I/VE ISSUED A FLASH FLOOD WATCH FOR THIS
AREA. I DID NOT TAKE IT ACROSS NRN MTNS...NRN FOOTHILLS OR THE WRN
NC/SC PIEDMONT AS ANTECEDENT CONDITIONS ARE DRIER. I HOPE I DON/T
REGRET THIS...BUT THE NEIGHBORING OFFICES ARE IN AGREEMENT ON THIS
APPROACH AS WELL.
OVERNIGHT THE AREA OF MID-LEVEL TROUGHING STRENGTHENS JUST A LITTLE
WITH SOUTHWESTERLY H5 WINDS INCREASING TO 25 KTS OVER THE WRN ZONES
ALONG WITH A COMMISERATE RESPONSE AND BACKING IN THE LLVL WIND
FIELD. THIS MAY SET THE STAGE FOR CONVECTION TO LAST A WAYS INTO THE
OVERNIGHT HOURS...OR EVEN REDEVELOP AT SOME POINT DURING THE THE
NIGHT. THE FLASH FLOOD WATCH WILL BE RUN THROUGH 6 AM FRIDAY TO
ACCOUNT FOR THIS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AT 230 AM EDT THURSDAY...AN UPPER RIDGE WILL EXTEND ACROSS THE
SOUTHEAST STATES ON FRIDAY...WHILE A CLOSED UPPER LOW CROSSES SOUTH
CENTRAL CANADA AND AN EASTERLY WAVE MOVES INTO THE SOUTHEAST GULF
OF MEXICO. THE RIDGE PERSISTS INTO SATURDAY...WHILE THE UPPER LOW
REACHES EASTERN CANADA...AND THE EASTERLY WAVE REACHES THE WESTERN
GULF.
AN ATLANTIC SURFACE RIDGE WILL MAINTAIN A HOLD ON THE CAROLINAS AND
GA ON FRIDAY...WHILE A RIVER OF GULF MOISTURE WILL EXTEND TO THE
SOUTHERN APPALACHIANS. ISENTROPIC UPGLIDE OVER THE RIDGE WILL BE
RATHER WEAK...AND UPSLOPE FLOW LIMITED BY THE SOUTHWESTERLY NATURE
OF THE WINDS. THE RIVER OF GULF MOISTURE BECOMES REORIENTED ON
SATURDAY AS THE EASTERLY WAVE AFFECTS THE GULF INFLOW...AND LOW
LEVEL WINDS VEER TO THE WEST...FAVORING THE TN BORDER FOR
PRECIPITATION. MEANWHILE...A SLOW MOVING COLD FRONT WILL OUT OF THE
OH RIVER VALLEY...APPROACHING OUR AREA FROM THE NORTH ON SUNDAY
NIGHT.
WITH DEEP MOISTURE REMAINING OVER OUR AREA...POPS WILL BE ABOVE
CLIMATOLOGY...AND WILL CONTINUE OVERNIGHT...DESPITE THE LACK OF WELL
DEFINED FORCING. ALTHOUGH QPF WILL BE LIMITED...ESPECIALLY AS FLOW
VEERS SATURDAY...THE LONG DURATION OF THE EVENT COULD PRODUCE RUNOFF
PROBLEMS IN AREAS THAT HAD GREATER RAINFALL EARLIER ON. A LIMITED
DIURNAL TEMPERATURE RANGE IS EXPECTED TO CONTINUE...WITH CLOUDS
KEEPING MAXIMUMS SLIGHTLY BELOW NORMAL...AND MINIMUMS SLIGHTLY ABOVE
NORMAL.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AT 230 AM EDT THURSDAY...AN UPPER TROUGH WILL AMPLIFY ALONG THE EAST
COAST FROM SUNDAY THROUGH WEDNESDAY. A COLD FRONT WILL DROP VERY
SLOWLY SOUTH INTO THE NORTHERN PORTION OF THE AREA ON SUNDAY...
CROSSING MUCH OF WESTERN NC ON MONDAY...THE INTERSTATE 85 CORRIDOR
TUESDAY...AND FINALLY MOVING SOUTH OF THE AREA ON WEDNESDAY.
ALTHOUGH THIS BOUNDARY WILL SERVE AS A FOCUSING MECHANISM FOR
PRECIPITATION...SOUTHERLY INFLOW AHEAD OF THE FRONT IS EXPECTED TO
DECREASE BASED ON A REORIENTATION OF THE SURFACE RIDGE TO THE SOUTH.
UPSLOPE WILL BE LIMITED TO THE TN BORDER AREA TO BEGIN WITH AS LOW
LEVEL WINDS WILL BE WESTERLY...AND WILL DIMINISH IN THE LEE OF THE
MOUNTAINS AS THE FRONT SETTLES SOUTH AND WINDS VEER MORE TO THE
NORTHWEST. POPS WILL REMAIN ABOVE CLIMATOLOGY...AND WITH SOME
UNCERTAINTY AS TO THE TIMING OF THE FRONT...POPS WILL BE ALLOWED TO
REMAIN INTO WEDNESDAY. TEMPERATURES WILL DECREASE AS HEIGHTS FALL
ALOFT...BUT THE DIURNAL RANGE WILL REMAIN LIMITED DUE TO CLOUDS AND
MOISTURE.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AT KCLT...MID-LEVEL CLOUDS AND LIGHT WINDS HELPED KEEP LOW STRATUS
FROM DEVELOPING THIS MORNING. AFTER SUNRISE...HOWEVER...ONCE THERE
IS A LITTLE HEATING SOME MVFR CIGS COULD DEVELOP...PROBABLY CLOSE TO
2KFT. WILL HINT THAT WAY WITH A SCT LAYER. SCT SHRA AND TSTMS ARE
EXPECTED IN THE AFTN...THOUGH CHANCES WILL CONTINUE TO BE HIGHER A
LITTLE CLOSER TO THE MOUNTAINS. STRATUS IS POSSIBLE AGAIN
TONIGHT...ESPECIALLY AS THE LOW LEVEL FLOW WILL BE A LITTLE
STRONGER. WENT WITH AN MVFR DECK TO ACCOUNT FOR THIS. CONFIDENCE
ISN/T VERY HIGH AS A LOT WILL DEPEND ON HOW MUCH PRECIPITATION FALLS
TODAY AND TONIGHT.
ELSEWHERE...HIGH CLOUDS AND LIGHT LLVL WINDS HAVE KEPT STRATUS FROM
DEVELOPING FOR THE MOST PART ACROSS MOST OF THE FOOTHILLS AND
PIEDMONT THIS MORNING. ASHEVILLE DID GO DOWN AND SHOULD GRADUALLY
LIFT OUT OF THE LIFR/VLIFR RANGE THIS MORNING. THERE IS STILL A
CHANCE THAT AN MVFR OR EVEN IFR DECK WILL DEVELOP ONCE THERE IS A
LITTLE HEATING AND MIXING AFTER SUNRISE. SCATTERED LAYERS WERE ADDED
OUTSIDE THE MOUNTAINS TO ACCOUNT FOR THIS. AN UPPER LOW WILL BRING A
GOOD CHANCE OF SHOWERS AND THUNDERSTORMS TO THE REGION THIS
AFTERNOON AND TEMPO GROUPS FOR THUNDER HAVE BEEN ADDED TO ALL THE
TAF SITES.
OUTLOOK...MOISTURE AND INSTABILITY CONTINUE THROUGH THE WEEKEND...
LEADING TO CONTINUED CHANCES FOR MAINLY DIURNAL CONVECTION. EARLY
MORNING PATCHY FOG AND LOW CLOUDS MAY OCCUR OVER AREAS OF RECENT
RAINFALL AND IN MTN VALLEYS.
CONFIDENCE TABLE...
11-17Z 17-23Z 23-05Z 05-11Z
KCLT MED 70% HIGH 81% HIGH 100% HIGH 85%
KGSP MED 67% MED 76% HIGH 87% LOW 54%
KAVL MED 63% HIGH 85% MED 63% MED 76%
KHKY MED 67% MED 74% MED 62% LOW 59%
KGMU MED 68% HIGH 81% HIGH 87% MED 63%
KAND LOW 57% HIGH 81% HIGH 100% HIGH 80%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR GAZ010-017-018-026-
028-029.
NC...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR NCZ062>065-509-510.
SC...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR SCZ001>007-010>012-
019.
&&
$$
SYNOPSIS...HG/JAT
NEAR TERM...MCAVOY
SHORT TERM...JAT
LONG TERM...JAT
AVIATION...HG/MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
315 AM EDT THU AUG 8 2013
.SYNOPSIS...
MOIST HIGH PRESSURE WILL REMAIN OVER THE AREA THROUGH SATURDAY. A
WEAK COLD FRONT ARRIVE FROM THE NORTH SUNDAY. THIS FRONT WILL SLOWLY
CROSS THE AREA THROUGH TUESDAY...BEFORE MOVING SOUTH OF THE AREA ON
WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE LATEST GSP-WSR88D WIND PROFILER DATA SHOW NORTHERLY FLOW BETWEEN
9-13 KFT. WHILE AT THE TCLT TDWR THE FLOW AT THIS LEVEL IS OUT OF
THE WSW. THE TROUGH IS ALSO EVIDENT IN THE REFLECTIVITIES AS PATCHY
LIGHT SHOWERS ARE MOVING OUT OF THE NORTH OVER THE CENTRAL PART OF
THE UPSTATE...BUT THEY ARE MOVING FROM THE SOUTH OVER TOWARD UNION
AND GAFFNEY. WHILE THIS IS A WEAK FEATURE IT MAY BE ENOUGH TO
FINALLY KEEP IT DRY THROUGH SUNRISE ON THE BACK SIDE OF THE TROUGH
ACROSS THE BLUE RIDGE. A COUPLE CONVECTION ALLOWING MODELS FIRE UP
HEAVIER SHOWERS AND STORMS EAST OF THE TROUGH AXIS PRIOR TO SUNRISE
HOWEVER. I/M NOT CERTAIN THAT THIS WON/T HAPPEN...BUT I DOUBT IT AT
THIS POINT.
LATER IN THE MORNING THE NAM AND RUC DEVELOP CONVECTION BACK ACROSS
THE BLUE RIDGE AS A STRONGER MID-TROPOSPHERIC TROUGH APPROACHES.
THIS FEATURE IS CURRENTLY EVIDENT ON THE RUC...AND MODESTLY EVIDENT
ON WATER VAPOR IMAGERY...OVER MIDDLE TN AND SW KY. THE SHORT WAVE IS
EXPECTED TO TRIGGER NUMEROUS SHOWERS AND TSTMS OVER MOUNTAINS AND
FOOTHILLS TODAY. EVEN THE PIEDMONT MIGHT GET INTO THE ACT AS THE
LLVL FLOW IS A LITTLE MORE SOUTHWESTERLY TODAY. AS SEVERAL INCHES OF
RAIN HAS FALLEN OVER PARTS OF NE GA...UPSTATE SC AND THE SRN MTNS OF
NC OVER THE PAST 3 DAYS...I/VE ISSUED A FLASH FLOOD WATCH FOR THIS
AREA. I DID NOT TAKE IT ACROSS NRN MTNS...NRN FOOTHILLS OR THE WRN
NC/SC PIEDMONT AS ANTECEDENT CONDITIONS ARE DRIER. I HOPE I DON/T
REGRET THIS...BUT THE NEIGHBORING OFFICES ARE IN AGREEMENT ON THIS
APPROACH AS WELL.
OVERNIGHT THE AREA OF MID-LEVEL TROUGHING STRENGTHENS JUST A LITTLE
WITH SOUTHWESTERLY H5 WINDS INCREASING TO 25 KTS OVER THE WRN ZONES
ALONG WITH A COMMISERATE RESPONSE AND BACKING IN THE LLVL WIND
FIELD. THIS MAY SET THE STAGE FOR CONVECTION TO LAST A WAYS INTO THE
OVERNIGHT HOURS...OR EVEN REDEVELOP AT SOME POINT DURING THE THE
NIGHT. THE FLASH FLOOD WATCH WILL BE RUN THROUGH 6 AM FRIDAY TO
ACCOUNT FOR THIS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AT 230 AM EDT THURSDAY...AN UPPER RIDGE WILL EXTEND ACROSS THE
SOUTHEAST STATES ON FRIDAY...WHILE A CLOSED UPPER LOW CROSSES SOUTH
CENTRAL CANADA AND AN EASTERLY WAVE MOVES INTO THE SOUTHEAST GULF
OF MEXICO. THE RIDGE PERSISTS INTO SATURDAY...WHILE THE UPPER LOW
REACHES EASTERN CANADA...AND THE EASTERLY WAVE REACHES THE WESTERN
GULF.
AN ATLANTIC SURFACE RIDGE WILL MAINTAIN A HOLD ON THE CAROLINAS AND
GA ON FRIDAY...WHILE A RIVER OF GULF MOISTURE WILL EXTEND TO THE
SOUTHERN APPALACHIANS. ISENTROPIC UPGLIDE OVER THE RIDGE WILL BE
RATHER WEAK...AND UPSLOPE FLOW LIMITED BY THE SOUTHWESTERLY NATURE
OF THE WINDS. THE RIVER OF GULF MOISTURE BECOMES REORIENTED ON
SATURDAY AS THE EASTERLY WAVE AFFECTS THE GULF INFLOW...AND LOW
LEVEL WINDS VEER TO THE WEST...FAVORING THE TN BORDER FOR
PRECIPITATION. MEANWHILE...A SLOW MOVING COLD FRONT WILL OUT OF THE
OH RIVER VALLEY...APPROACHING OUR AREA FROM THE NORTH ON SUNDAY
NIGHT.
WITH DEEP MOISTURE REMAINING OVER OUR AREA...POPS WILL BE ABOVE
CLIMATOLOGY...AND WILL CONTINUE OVERNIGHT...DESPITE THE LACK OF WELL
DEFINED FORCING. ALTHOUGH QPF WILL BE LIMITED...ESPECIALLY AS FLOW
VEERS SATURDAY...THE LONG DURATION OF THE EVENT COULD PRODUCE RUNOFF
PROBLEMS IN AREAS THAT HAD GREATER RAINFALL EARLIER ON. A LIMITED
DIURNAL TEMPERATURE RANGE IS EXPECTED TO CONTINUE...WITH CLOUDS
KEEPING MAXIMUMS SLIGHTLY BELOW NORMAL...AND MINIMUMS SLIGHTLY ABOVE
NORMAL.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AT 230 AM EDT THURSDAY...AN UPPER TROUGH WILL AMPLIFY ALONG THE EAST
COAST FROM SUNDAY THROUGH WEDNESDAY. A COLD FRONT WILL DROP VERY
SLOWLY SOUTH INTO THE NORTHERN PORTION OF THE AREA ON SUNDAY...
CROSSING MUCH OF WESTERN NC ON MONDAY...THE INTERSTATE 85 CORRIDOR
TUESDAY...AND FINALLY MOVING SOUTH OF THE AREA ON WEDNESDAY.
ALTHOUGH THIS BOUNDARY WILL SERVE AS A FOCUSING MECHANISM FOR
PRECIPITATION...SOUTHERLY INFLOW AHEAD OF THE FRONT IS EXPECTED TO
DECREASE BASED ON A REORIENTATION OF THE SURFACE RIDGE TO THE SOUTH.
UPSLOPE WILL BE LIMITED TO THE TN BORDER AREA TO BEGIN WITH AS LOW
LEVEL WINDS WILL BE WESTERLY...AND WILL DIMINISH IN THE LEE OF THE
MOUNTAINS AS THE FRONT SETTLES SOUTH AND WINDS VEER MORE TO THE
NORTHWEST. POPS WILL REMAIN ABOVE CLIMATOLOGY...AND WITH SOME
UNCERTAINTY AS TO THE TIMING OF THE FRONT...POPS WILL BE ALLOWED TO
REMAIN INTO WEDNESDAY. TEMPERATURES WILL DECREASE AS HEIGHTS FALL
ALOFT...BUT THE DIURNAL RANGE WILL REMAIN LIMITED DUE TO CLOUDS AND
MOISTURE.
&&
.AVIATION /07Z THURSDAY THROUGH MONDAY/...
AT KCLT...A SOLID DECK OF MID LEVEL CLOUDS HAS DEVELOPED UP AROUND
140KFT. THERE ARE A COUPLE OTHER LOWER DECKS AS WELL. SOME LIGHT
RAIN IS FALLING OUT OF SOME OF THESE CLOUDS. EXPECT IFR STRATUS TO
DEVELOP...BUT IT SHOULD TAKE A WHILE WITH ALL THE HIGHER LEVEL
CLOUDS. ALSO...A COUPLE COMPUTER MODELS DEVELOP THUNDERSTORMS AND
HEAVY RAIN STARTING IN A COUPLE HOURS. THERE HAS BEEN PLENTY OF
OVERNIGHT THUNDERSTORM ACTIVITY LATELY SO I/M NOT COMPLETELY
DISREGARDING THIS...BUT I HAVEN/T INCLUDED THAT IN THE TAFS.
STRATUS WILL SLOWLY BURN OFF DURING THE MORNING HOURS. SCT SHRA AND
TSTMS ARE EXPECTED IN THE AFTN...THOUGH CHANCES WILL CONTINUE TO BE
HIGHER A LITTLE CLOSER TO THE MOUNTAINS.
ELSEWHERE...SEVERAL DIFFERENT CLOUD LAYERS COVER THE REGION EARLY
THIS MORNING. THERE IS A DECK UP AROUND 140KFT AND SEVERAL LOWER
ONES AS WELL. HOWEVER...MOST OF THESE CLOUDS ARE IN THE VFR RANGE.
WITH A VERY MOIST ATMOSPHERE AND LIGHT SW WINDS WE SHOULD SEE IFR
STRATUS DEVELOP...THOUGH IT MAY BE PATCHY CONSIDERING THE HIGH CLOUD
COVER. I HAVE ACCOUNTED FOR THIS WITH A LONG PERIOD OF TEMPO
GROUPS. THE EXCEPTION MAY BE KAVL WHERE LIFR CIGS HAVE ALREADY
DEVELOPED. CLOUDS ARE NOT AS THICK OVER HKY WHICH WILL GIVE THEM A
BETTER CHANCE OF A SOLID IFR STRATUS DECK AND SOME FOG. SHRA AND
EVEN A FEW TSMTS MAY DEVELOP OVER THE REGION IN A FEW HOURS. BETTER
CHANCES WILL BE FOUND THIS AFTERNOON...UNLESS THE CONVECTION SIMPLY
KEEPS GOING TROUGH THE MORNING HOURS LIKE IT DID YDAY.
OUTLOOK...MOISTURE AND INSTABILITY CONTINUE THROUGH THE WEEKEND...
LEADING TO CONTINUED CHANCES FOR MAINLY DIURNAL CONVECTION. EARLY
MORNING PATCHY FOG AND LOW CLOUDS MAY OCCUR OVER AREAS OF RECENT
RAINFALL AND IN MTN VALLEYS.
CONFIDENCE TABLE...
07-13Z 13-19Z 19-01Z 01-07Z
KCLT HIGH 81% MED 74% HIGH 91% HIGH 100%
KGSP MED 76% MED 79% HIGH 85% HIGH 83%
KAVL HIGH 86% HIGH 83% HIGH 85% HIGH 80%
KHKY LOW 46% MED 79% MED 77% MED 78%
KGMU MED 71% MED 76% HIGH 87% HIGH 83%
KAND LOW 58% MED 69% HIGH 90% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR GAZ010-017-018-026-
028-029.
NC...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR NCZ062>065-509-510.
SC...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR SCZ001>007-010>012-
019.
&&
$$
SYNOPSIS...JAT
NEAR TERM...MCAVOY
SHORT TERM...JAT
LONG TERM...JAT
AVIATION...MCAVOY
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1238 PM CDT THU AUG 8 2013
.UPDATE...
SEE UPDATED AVIATION DISCUSSION BELOW.
MADE A FEW ADJUSTMENTS TO WX/POPS FOR TODAY...MAINLY JUST SHAVING
OFF THE NORTH END WHERE CONDITIONS LOOK TO BE DRY NORTH OF THE
STALLED FRONTAL BOUNDARY. ANY ADDITIONAL SHOWER AND STORM
DEVELOPMENT THROUGH THE DAY LOOKS TO BE MAINLY NEAR AND SOUTH OF
HWY 212. LATEST HRRR RUN AND LAST NIGHTS 00Z NSSL WRF RUN ALSO
SUGGESTING THIS. CURRENT HIGHS APPEAR ON TRACK AT THIS POINT AND
NO CHANGES THERE. READINGS WILL TOP OUT IN THE 70S FOR MOST
LOCATIONS...STILL BELOW NORMAL FOR THIS TIME OF YEAR.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH SATURDAY
AN AREA OF HIGH PRESSURE MOVING INTO THE REGION FROM THE NORTH
WILL PUSH A WEAK FRONTAL BOUNDARY DRAPED FROM WEST TO EAST ACROSS
CENTRAL SOUTH DAKOTA SOUTHWARD TODAY. MODELS GENERALLY AGREE WITH
PLACEMENT OF THIS FRONTAL BOUNDARY ACROSS SOUTHERN SOUTH DAKOTA
WHERE STORMS HAVE THE BEST POTENTIAL OF DEVELOPING LATER THIS
AFTERNOON. BECAUSE OF THE SOUTHERN PLACEMENT OF THE FRONTAL BOUNDARY
HAVE REMOVED POPS ACROSS THE NORTHERN PORTION OF THE CWA FOR THIS
AFTERNOON.
CANADIAN HIGH PRESSURE BUILDING INTO THE REGION TONIGHT WILL
PRODUCE DRY CONDITIONS THROUGH THE DAY ON FRIDAY. RETURN FLOW WILL
QUICKLY DEVELOP ON THE BACK SIDE OF THE HIGH PRESSURE ON FRIDAY
NIGHT OVER THE WESTERN DAKOTAS. A FAIRLY STRONG SHORT WAVE MOVING
ACROSS THE REGION WILL INTERACT WITH THE INCREASING LLM TO RESULT
IN EARLY MORNING CONVECTION FOR THE WESTERN CWA ON SATURDAY.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
DESPITE ALLBLENDS GENEROUS SMATTERING OF POPS OVER SEVERAL OF THE
EXTENDED FORECAST PERIODS...SATURDAY NIGHT/SUNDAY STILL STANDS THE
BEST CHANCE OF NUMEROUS/WIDESPREAD COVERAGE OF SHOWERS AND
THUNDERSTORMS. INSTABILITY/SHEAR AND FORCING IS ALL THERE IN
SUPPORT OF SOME SORT OF ORGANIZED CONVECTIVE SYSTEM
EVOLVING/MOVING ACROSS THE CWA SATURDAY NIGHT INTO SUNDAY MORNING.
BEYOND THAT...AS WAS PREVIOUSLY MENTIONED...DETAILS GET A LITTLE
BIT FUZZIER AS SOLUTIONS BEGIN TO DIVERGE ON THE HANDLING OF
PLACEMENT/STRENGTH OF THE WESTERN CONUS UPPER LEVEL RIDGE /AND ANY
SHORT-WAVE IMPULSES EMBEDDED WITHIN THE FLOW/ WHICH IS THOUGHT TO
BE SHIFTING A BIT EAST TOWARD THE DAKOTAS BY MID-WEEK.
ALSO STILL LOOKS AS THOUGH TEMPERATURES MAY TRY TO
MODERATE/WARM-UP A BIT TOWARD THE MID TO LATE PART OF THIS COMING
WEEK...AT LEAST...CLOSER TO NORMAL FOR AUGUST.
&&
.AVIATION...
18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
OTHER THAN SOME MVFR CIGS LINGERING OVER PARTS OF THE EASTERN CWA
INTO THE EARLY TO MID AFTERNOON HOURS...VFR CONDITIONS WILL
PREVAIL ACROSS THE AREA THROUGH MIDDAY FRIDAY.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...TMT
SHORT TERM...SD
LONG TERM...DORN
AVIATION...PARKIN
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
947 AM CDT THU AUG 8 2013
.UPDATE...REST OF TODAY
MADE A FEW ADJUSTMENTS TO WX/POPS FOR TODAY...MAINLY JUST SHAVING
OFF THE NORTH END WHERE CONDITIONS LOOK TO BE DRY NORTH OF THE
STALLED FRONTAL BOUNDARY. ANY ADDITIONAL SHOWER AND STORM
DEVELOPMENT THROUGH THE DAY LOOKS TO BE MAINLY NEAR AND SOUTH OF
HWY 212. LATEST HRRR RUN AND LAST NIGHTS 00Z NSSL WRF RUN ALSO
SUGGESTING THIS. CURRENT HIGHS APPEAR ON TRACK AT THIS POINT AND
NO CHANGES THERE. READINGS WILL TOP OUT IN THE 70S FOR MOST
LOCATIONS...STILL BELOW NORMAL FOR THIS TIME OF YEAR.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH SATURDAY
AN AREA OF HIGH PRESSURE MOVING INTO THE REGION FROM THE NORTH
WILL PUSH A WEAK FRONTAL BOUNDARY DRAPED FROM WEST TO EAST ACROSS
CENTRAL SOUTH DAKOTA SOUTHWARD TODAY. MODELS GENERALLY AGREE WITH
PLACEMENT OF THIS FRONTAL BOUNDARY ACROSS SOUTHERN SOUTH DAKOTA
WHERE STORMS HAVE THE BEST POTENTIAL OF DEVELOPING LATER THIS
AFTERNOON. BECAUSE OF THE SOUTHERN PLACEMENT OF THE FRONTAL BOUNDARY
HAVE REMOVED POPS ACROSS THE NORTHERN PORTION OF THE CWA FOR THIS
AFTERNOON.
CANADIAN HIGH PRESSURE BUILDING INTO THE REGION TONIGHT WILL
PRODUCE DRY CONDITIONS THROUGH THE DAY ON FRIDAY. RETURN FLOW WILL
QUICKLY DEVELOP ON THE BACK SIDE OF THE HIGH PRESSURE ON FRIDAY
NIGHT OVER THE WESTERN DAKOTAS. A FAIRLY STRONG SHORT WAVE MOVING
ACROSS THE REGION WILL INTERACT WITH THE INCREASING LLM TO RESULT
IN EARLY MORNING CONVECTION FOR THE WESTERN CWA ON SATURDAY.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY NIGHT
DESPITE ALLBLEND`S GENEROUS SMATTERING OF POPS OVER SEVERAL OF THE
EXTENDED FORECAST PERIODS...SATURDAY NIGHT/SUNDAY STILL STANDS THE
BEST CHANCE OF NUMEROUS/WIDESPREAD COVERAGE OF SHOWERS AND
THUNDERSTORMS. INSTABILITY/SHEAR AND FORCING IS ALL THERE IN
SUPPORT OF SOME SORT OF ORGANIZED CONVECTIVE SYSTEM
EVOLVING/MOVING ACROSS THE CWA SATURDAY NIGHT INTO SUNDAY MORNING.
BEYOND THAT...AS WAS PREVIOUSLY MENTIONED...DETAILS GET A LITTLE
BIT FUZZIER AS SOLUTIONS BEGIN TO DIVERGE ON THE HANDLING OF
PLACEMENT/STRENGTH OF THE WESTERN CONUS UPPER LEVEL RIDGE /AND ANY
SHORT-WAVE IMPULSES EMBEDDED WITHIN THE FLOW/ WHICH IS THOUGHT TO
BE SHIFTING A BIT EAST TOWARD THE DAKOTAS BY MID-WEEK.
ALSO STILL LOOKS AS THOUGH TEMPERATURES MAY TRY TO
MODERATE/WARM-UP A BIT TOWARD THE MID TO LATE PART OF THIS COMING
WEEK...AT LEAST...CLOSER TO NORMAL FOR AUGUST.
&&
.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
JUST A COUPLE OF WEAK SHOWERS LEFT ACROSS THE CWA THIS MORNING AS
FORCING/LIFT FOR CONVECTION IS DIMINISHING. CURRENT VFR
CONDITIONS...EXCEPT AT KATY /MVFR CIGS THERE/...ARE EXPECTED TO
CONTINUE TODAY AND TONIGHT. KATY SHOULD SEE CONDITIONS GRADUALLY
IMPROVING BY LATE THIS MORNING/EARLY AFTERNOON TO VFR. A FEW
SHOWERS AND THUNDERSTORMS COULD FIRE ALONG/SOUTH OF A SLOWLY
SAGGING FRONTAL BOUNDARY. KPIR COULD SEE A COUPLE OF THESE STORMS
NEARBY. BUT OVERALL...DRY CONDITIONS AMID GOOD VFR IS EXPECTED TO
PREVAIL.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...TMT
SHORT TERM...SD
LONG TERM...DORN
AVIATION...DORN
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
819 PM CDT FRI AUG 9 2013
.UPDATE...SCATTERED CONVECTION HAS BEEN TRENDING DOWNWARD IN
COVERAGE AND INTENSITY...AND SEE NO REASON FOR THIS TO CHANGE
THROUGH LATE EVENING. HAVE LOWERED POPS AND QPF ACROSS THE AREA
TO INDICATE "SCATTERED" THUNDERSTORMS OVERNIGHT AND AVERAGE
RAINFALL AMOUNTS UNDER ONE QUARTER INCH. OF COURSE...WITH THE VERY
MOIST AIR MASS STILL IN PLACE...LOCALIZED HEAVY RAINFALL IS STILL
A POSSIBILITY. SHORT RANGE MODELS INCLUDING LATEST HRRR SHOW ONLY
SCATTERED AT BEST OVERNIGHT...BUT DO HINT AT INCREASING ACTIVITY
TOWARD DAYBREAK COMING IN FROM THE NORTHWEST AS THE QUASI
STATIONARY FRONT DIPS A LITTLE CLOSER AND A SHEARING UPPER WAVE
APPROACHES. STILL EXPECT ACTIVITY TO BECOME MORE WIDESPREAD ON
SATURDAY WITH FRONT OVER THE REGION.
13
&&
.PREV DISCUSSION... /ISSUED 635 PM CDT FRI AUG 9 2013/
UPDATE...FOR 00Z AVIATION.
AVIATION...00Z TAF DISCUSSION.
SCATTERED SH/TS ONGOING AT ISSUANCE ACROSS NORTHERN MIDDLE TN.
MAINLY VC AT TAF TERMINALS BUT ALL SITES COULD SEE A BRIEF TS OR
SHRA THROUGH 03Z BEFORE THINGS BEGIN TO QUIET DOWN. FLIGHT
CATEGORIES WILL DROP AGAIN TONIGHT. IFR LIKELY AT CSV...WITH AT
LEAST MVFR AT BNA AND CKV...AND IMPROVING THROUGH THE MORNING
HOURS. RAINY PATTERN WILL CONTINUE WITH A WARM FRONT THAT IS
EXPECTED TO DIP FAR ENOUGH INTO THE AREA TO ALLOW WINDS TO SHIFT
AROUND TO THE NW BY MORNING...THOUGH THEY ARE EXPECTED TO BE
LIGHT. MORE RAINS WILL COME WITH THE WARM FRONT DRAPED ACROSS THE
MIDDLE PORTION OF THE STATE...BUT PINPOINTING A TIME WILL BE
DIFFICULT. WILL HANDLE WITH VC STARTING AS EARLY AS 10Z AT
CKV...SPREADING TO THE REST OF OUR TERMINALS THROUGH THE MORNING
HOURS...AND LIKELY REMAINING IN THE AREA THROUGH THE END OF THIS
TAF PERIOD.
UNGER
PREV DISCUSSION... /ISSUED 246 PM CDT FRI AUG 9 2013/
DISCUSSION...
TIGHT MESO CONVECTIVE VORTICITY CENTER CAN BE SEEN IN LATEST
VISIBLE LOOP NEARING POPLAR BLUFF MISSOURI AT 19Z. THIS FEATURE
HAS KICKED OFF A GRAVITY WAVE NOW EAST OF MISSISSIPPI RIVER. THE
GRAVITY WAVE WILL CONTINUE TO PROPAGATE EASTWARD AND INTO MIDDLE
TENNESSEE DURING THE AFTERNOON. 4000 PLUS SURFACE BASED CAPES
EXTEND FROM NORTHEAST MISSISSIPPI NORTHEASTWARD INTO NASHVILLE
THIS AFTERNOON WITH CONVECTION CONCENTRATED IN THIS AREA.
THE ATMOSPHERE ACROSS A BROAD SWATH FROM PLAINS THROUGH THE
TENNESSEE VALLEY IS LADEN WITH MOISTURE WITH THE BEST MOISTURE
TRANSPORT TONIGHT BEING FROM NORTHERN ARKANSAS ACROSS WEST
TENNESSEE AND THE NORTH HALF OF MIDDLE TENNESSEE WHERE LOCALLY ONE
INCH OR MORE OF RAIN COULD FALL AT JUST ABOUT ANY LOCATION IN
MIDDLE TENNESSEE OVERNIGHT WITH MORE LOCALLY HEAVY RAINFALL DURING
THE DAY ON SATURDAY AS SURFACE FRONT TO OUR NORTHWEST SAGS DOWN
INTO MIDDLE TENNESSEE BEFORE LIFTING BACK NORTHWARD AS WARM FRONT
BECOMING STATIONARY ALONG THE OHIO RIVER BY SUNDAY. FRONT FINALLY
PUSHES THROUGH MID STATE ON WEDNESDAY WITH HIGH PRESSURE CENTERED
OVER HIGH PLAINS MOVING INTO THE UPPER MID WEST BY THURSDAY. HIGH
TEMPS GET KNOCKED DOWN ABOUT 5 DEGREES BEGINNING ON WEDNESDAY.
BOYD
&&
.OHX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1145 PM CDT WED AUG 7 2013
.UPDATE...
UPDATED FOR 06Z AVIATION DISCUSSION.
&&
.PREV DISCUSSION... /ISSUED 740 PM CDT WED AUG 7 2013/
UPDATE...
DIFFICULT TO GET A HANDLE ON EXACTLY WHERE ANY SHOWERS AND
THUNDERSTORMS WILL DEVELOP THIS EVENING WITH MANY OF THE MODELS
BEING POOR IN HANDLING THE CURRENT SITUATION. A WEAK WARM EXTENDS
FROM NORTHEAST AR INTO SOUTHWEST TN AT EARLY EVENING. A FEW
SHOWERS AND THUNDERSTORMS HAVE DEVELOPED ALONG THE TN RIVER IN
WEST TN JUST NORTH OF THIS FRONT. THE HIGH RESOLUTION RAPID
REFRESH MODEL SEEMS TO BE DOING THE BEST JOB...AND THIS MODEL
INDICATE FURTHER DEVELOPMENT THIS EVENING NORTH OF THE FRONT
ACROSS PORTIONS OF NORTHEAST AR...THE MO BOOTHEEL...AND PORTIONS
OF WEST TN. UPDATED TO REMOVE MENTION OF RAIN THIS EVENING SOUTH
OF THIS AREA. ALSO ADJUSTED THE SKY COVER A LITTLE FOR THIS
EVENING...OTHERWISE LITTLE CHANGE MADE TO THE EARLIER FORECAST.
JCL
&&
.PREV DISCUSSION... /ISSUED 312 PM CDT WED AUG 7 2013/
THE OUTFLOW BOUNDARY GENERATED FROM THIS MORNINGS MCS CONTINUES TO
PUSH ACROSS NORTHERN MISSISSIPPI. SCATTERED SHOWERS AND THUNDERSTORMS
HAVE DEVELOPED ALONG AND IN ADVANCE OF THE BOUNDARY AND WILL
CONTINUE TO PUSH ACROSS THE REMAINDER OF NORTH MISSISSIPPI OVER
THE NEXT COUPLE OF HOURS. THESE STORMS COULD BE STRONG WITH GUSTY
WINDS AND HEAVY RAIN. THE BOUNDARY HAS LIMITED HIGH TEMPS ACROSS
THE DELTA THOUGH THE SOUTHERN MOST COUNTIES...FROM TALLAHATCHIE TO
MONROE...HAVE WARMED INTO THE MID 90S WITH HEAT INDEX VALUES
FLIRTING WITH 105 DEGREES. THE REMNANTS OF THE COLD POOL HAVE
RESULTED IN A RELATIVELY NICE DAY ACROSS MUCH OF EASTERN AR...THE
MO BOOTHEEL AND WEST TENNESSEE WHERE TEMPS ARE MOSTLY IN THE 80S
TO AROUND 90. THE AIRMASS STILL QUITE STABLE AND PRECIP FREE.
TONIGHT...LOOKING AT A FAIRLY QUIET EVENING GIVEN THE WORKED OVER
AIRMASS IN PLACE. WENT WITH A 20 POP OVER MOST OF THE AREA AND A
30 POP OVER NE ARKANSAS WHERE THE HRRR IS HINTING AT SOME
DEVELOPMENT BEFORE MIDNIGHT. LOOKING AT ANOTHER POTENTIAL MCS
SCENARIO LATER TONIGHT AS THE LOW LEVEL JET REDEVELOPS OVER
EASTERN OK AND WESTERN AR AND IMPINGES UPON THE WEAK STATIONARY
FRONT ACROSS THE AREA. THIS FRONT HAS BEEN HAVING TROUBLE LIFTING
NORTH OVER THE LAST COUPLE OF DAYS THANKS TO THE RECENT MCS
ACTIVITY AND ASSOCD COLD POOLS. AN AREA OF SHOWERS AND
THUNDERSTORMS SHOULD BLOSSOM OVER SRN MISSOURI AFTER MIDNIGHT AND
THEN HEAD ESE AND SKIRT THE NORTHERN TIER OF THE MIDSOUTH BY
MORNING. POPS WILL DECREASE SHARPLY TOWARD SOUTHERN AREAS OF THE
MIDSOUTH. ANOTHER MILD NIGHT ON TAP WITH LOWS IN THE MID 70S.
THURSDAY...EXPECT THE MCS TO SKIRT THE NORTHERN TIER AND WEAKEN AS
IT SPREADS EAST. BEST CHANCE WILL BE ACROSS NORTHERN AND EASTERN
SECTION WITH LESSER CHANCES TOWARD THE SOUTHWEST. MEX GUIDANCE
CONTINUES TO BE VERY WARM AND WENT CLOSER TO THE COOLER MET
GUIDANCE. EXPECT THAT ANOTHER OUTFLOW BOUNDARY MAY PUSH SOUTH WHICH
WILL HELP KEEP A LID ON TEMPS. AREAS SOUTHWEST OF MEMPHIS ARE
LIKELY TO GET THE WARMEST AND COULD FLIRT WITH HEAT ADVISORY
CRITERIA.
THURSDAY NIGHT THROUGH FRIDAY NIGHT...PATTERN REMAINS SIMILAR
WITH A BROAD UPPER RIDGE ACROSS THE SOUTHERN U.S AND A WEAK
STATIONARY FRONT ACROSS SOUTHERN MISSOURI. EXPECT MCS DEVELOPMENT
ALONG THIS FRONT EACH NIGHT WITH THE BEST CHANCES OF PRECIP ALONG
THE NORTHERN TIER OF THE MIDSOUTH. CONTINUED TO PREFER THE COOLER
MET GUIDANCE THOUGH PARTS OF NORTH MISSISSIPPI AND EAST CENTRAL
ARKANSAS WILL FLIRT WITH HEAT ADVISORY CRITERIA ON FRIDAY.
SATURDAY THROUGH SUNDAY...CONFIDENCE STARTING TO WANE AT THIS
POINT. UPPER RIDGE REMAINS ACROSS THE SOUTHERN U.S. WHILE THE WEAK
BOUNDARY TRIES TO SLIP SOUTH INTO THE MIDSOUTH BUT REALLY DOES
NOT MOVE MUCH. CHANCES FOR SHOWERS AND THUNDERSTORMS EXPECTED ACROSS
THE REGION. MEX STILL TOO WARM.
MONDAY THROUGH WEDNESDAY...MEDIUM RANGE MODELS INDICATE THAT AN
UPPER TROF WILL DEVELOP OVER THE EASTERN U.S. EARLY NEXT WEEK. THE
GFS IS NOT AS DEEP WITH THE TROF WHICH REESTABLISHES NORTHWEST
FLOW ACROSS THE REGION AND KEEPS THE SURFACE BOUNDARY IN THE AREA
RESULTING IN A RENEWED MCS PATTERN. THE ECMWF HAS A DEEPER TROF
AND ACTUALLY PUSHES THE FRONT SOUTH...SHUTTING OFF PRECIP
CHANCES. FOR NOW JUST WENT WITH A COMPROMISE OF 20 POPS AND
SLIGHTLY COOLER THAN NORMAL TEMPS.
SJM
&&
.AVIATION...
06Z TAF CYCLE
GROWING CONFIDENCE THAT THIS TAF PERIOD WILL BECOME A BIT MORE
ACTIVE THEN PREVIOUS 00Z THINKING...WITH SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS DEVELOPING IN THE MEM...JBR...MKL CORRIDOR
BEFORE SUNRISE WITH MVFR VISIBILITIES AT TIMES. BETTER CHANCES
FOR THUNDER WILL BE LATER IN THE DAY AS THE CURRENT DISTURBANCE IN
THE SOUTHERN PLAINS MOVES ACROSS THE OZARKS. FOR NOW...PLACED
TEMPO IN AT JBR...AND VCTS ELSEWHERE...BUT TIMING/COVERAGE COULD
EASILY CHANGE WITH LATER FORECASTS.
WINDS WILL BE LIGHT AND VARIABLE OVERNIGHT...WITH THE EXCEPTION
OF SOUTH WINDS AT MEM. OUTFLOW BOUNDARY FROM MORNING COMPLEX WILL
SHIFT THE WINDS MORE EASTERLY AT 6-8 KTS FOR MEM...MKL AND
JBR...WHILE TUP REMAINS SOUTH. WINDS WILL AGAIN BECOME LIGHT FROM
THE EAST AND SUTHEAST NEAR SUNSET.
JAB
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 77 93 78 94 / 30 30 10 30
MKL 73 88 74 91 / 50 60 30 40
JBR 75 90 75 92 / 50 40 30 40
TUP 75 93 75 93 / 20 40 10 40
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
620 PM CDT FRI AUG 9 2013
.DISCUSSION...
/See Aviation Discussion below/
&&
.AVIATION...
Primary aviation concerns the next 3 to 4 hours are local areas of
showers and isolated thunderstorms that may product gusty
surface winds to 45kt...brief heavy rain and hazardous lightning.
Currently some showers and thunderstorms...with measured
lightning...are noted in Shackelford...Jones...Coke and Sterling
counties.
Showers are associated with a very weak frontal boundary stretching
from east-northeast to west-southwest through Jones and Sterling
Counties. Satellite imagery...radar imagery and models concur...the
front will move slowly toward the south-southeast the next 24 hours
weakening as it goes...then nearly dissipate southeast of Junction
and Kimble County on Saturday. Winds across Junction... Sonora...
San Angelo and Brady will shift from light southerly ahead of the
front to light northerly as the front passes to the southeast.
.PREV DISCUSSION... /ISSUED 307 PM CDT FRI AUG 9 2013/
.SHORT TERM...
.Tonight and Saturday...
Isolated severe thunderstorms with damaging winds possible again
this afternoon and evening. The best potential will be in the Big
Country, along a weak cold front along the I-20 corridor.
Discussion:
Conditions are similar to yesterday with an inverted V sounding.
Instability was fairly high. RAP ML CAPES ranged from 2000-3000 J/KG
in the Big Country and Concho Valley, with the highest values near
Sweetwater. Focus for initial storm development will be a weak front
along the I-20 corridor...although a few storms will likely develop
farther south along thunderstorm outflow boundaries. Main
thunderstorm threat will be damaging winds. With weak steering
currents, storm movement will be slow. This may also bring
localized flooding in urban areas.
The front is expected to move south Saturday afternoon...becoming
stationary somewhere along the I-10 corridor...although placement is
uncertain. The main threat will be strong gusty winds and dangerous
lightning.
.LONG TERM...
.Saturday Night...
Slight chance of storms will linger into the evening hours.
Whatever is left of the weak cold front will remain somewhere across
West Central Texas, along with whatever outflow boundaries may still
be in the area. Any storms that develop during the heat of the day
will keep going until shortly after sunset before dissipating.
.Sunday into Wednesday...
A dry pattern will prevail, with temperatures not quite as hot.
Upper level ridge of high pressure takes a bigger role for early
next week, slowly shifting back to the west. Low level temperatures
and 850 mb readings are FORECASTED to be cooler by a few degrees, so
forecast highs at or hopefully just below the 100 degree mark. With
the ridge in place overhead and without a boundary to aid, getting
any thunderstorms to develop will be extremely tough. Will opt to
keep the forecast dry.
.Wednesday Night into Friday...
Storms will be possible again across the Big Country.
By late Wednesday, the upper level ridge will have shifted far
enough to the west to put West Central Texas into northwest flow.
This is typically a wetter pattern, as storms develop across the
Panhandle during the afternoon and move southeast into the area
during the overnight hours. Best chances look to be across the Big
Country and Heartland with the chances decreasing to the southwest.
Have inserted pops for the northeast portions of the area for now,
and leave the remainder of the area dry. But if the northwest flow
sets up as the models suggest, may have to expand the rainfall
coverage as we get into next week.
Otherwise, northwest flow is usually a little cooler as well. This
is shown in the model guidance, showing highs near climatology
normals in the mid to upper 90s.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 100 71 96 76 96 / 20 30 20 20 10
SAN ANGELO 103 71 99 74 97 / 20 30 20 20 10
JUNCTION 103 72 100 75 97 / 10 5 20 20 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
LYONS
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
752 AM EDT THU AUG 8 2013
.SYNOPSIS...
A COUPLE OF DISTURBANCES SHIFT ACROSS THE AREA THROUGH TONIGHT. A
FRONT MOVES INTO THE MOUNTAINS BY SATURDAY AND SLOWLY SHIFTS TO
THE SOUTH OF US AFTER THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 720 AM EDT THURSDAY...
POCKETS OF SHOWERS/ISOLATED THUNDER MOVING ACROSS SE WV AT THE
MOMENT WILL AFFECT THE ALLGHENY HIGHLANDS SOON...WITH ISOLATED
SHOWERS PUSHING ACROSS THE TRIAD OF NC. FURTHER WEST A LINE OF
SHOWERS AND STORMS EXTENDS FROM LONDON KY WSW TO NASHVILLE TN. THE
LATEST HRRR APPEARS TO BE PICKING THIS UP PRETTY WELL BUT LINGERS
IT GOING INTO THIS MORNING WITH ONLY SCATTERED SHOWERS AFFECTING
THE WESTERN CWA. THE 00Z ECM MODEL WAS STILL DOING A GOOD ENOUGH
JOB BRINGING EMBEDDED IMPULSE OVER WV THIS MORNING INTO THE
SHENANDOAH VALLEY THIS AFTERNOON...WHILE THE KY WAVE MOVING INTO
FAR SW VA INTO NE TN. MADE SOME MINOR ADJUSTMENTS TO POPS BUT
OVERALL CONFIDENT IN HIGH CHANCE TO LIKELYS WEST TO LOWER CHANCES
OUT EAST. IF THERE IS ANY SUN...THE THUNDERSTORM CHANCES WILL
INCREASE...BUT OVERALL LOOKS LIKE ANOTHER MOSTLY CLOUDY TO OVC
DAY IN THE GRAND SCHEME OF THINGS.
PREVIOUS VALID DISCUSSION...
WITH PWATS AROUND 2.0 THE STORMS WILL BE EFFICIENT HEAVY RAIN
PRODUCERS...BUT GIVEN LACK OF WIDESPREAD RAINFALL LATELY A FLASH
FLOOD WATCH IS NOT WARRANTED. HOWEVER...SOME PLACES LIKE SUMMERS
COUNTY WV WHICH SAW SOME HEAVY RAIN WEDNESDAY IS MORE LIKELY TO BE
IMPACTED IF HEAVY RAIN MOVES SLOWLY OVER THEM TODAY. WILL HOLD OFF
AND SEE HOW THE CONVECTION TRANSPIRES TODAY BEFORE ISSUING A
WATCH.
THE ONE MAIN VORT MOVES EAST OF THE CWA BY EVENING SO EXPECT SOME
WEAKENING/DIMINISHING TREND IN THE POPS OUT EAST. THE FLOW ALOFT AND
MODEL VORTICITY FIELDS OF THE ECMWF CONTINUE TO SHOW EMBEDDED WAVES
MOVING FROM KENTUCKY INTO VIRGINIA/WEST VIRGINIA TONIGHT...AND
POSSIBLY INTO NC. LIKE THE ECMWF IDEA OF MAINTAIN HIGHER POPS ACROSS
SE WV INTO FAR SW VA...WITH LESS IN THE SOUTHEAST.
FOR TEMPS TODAY AND TONIGHT KEPT CLOSE TO WEDNESDAYS HIGHS WITH
MID 70S NC MOUNTAINS TO NEAR 80S BLF-BCB AND LOWER TO MID 80S
EAST. TONIGHT...SAME AIRMASS SO LOW SHOULD BE IN THE MID TO UPPER
60S WEST TO LOWER 70S EAST.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
AS OF 400 AM EDT THURSDAY...
LOOKING AT AN INCREASED THREAT OF LOCALLY HEAVY RAIN AND POSSIBLY
FLASH FLOODING ON FRIDAY AS A STRONG SHORTWAVE TROUGH PASSES EAST
ACROSS THE GREAT LAKES DURING THE AFTERNOON AND EVENING. THE
COMBINATION OF DEEP ATMOSPHERIC MOISTURE BUILDING ALONG THE CENTRAL
APPALACHIAN CHAIN AHEAD OF THE TROUGH...MODEST INSTABILITY AND
RELATIVELY LIGHT WINDS ALOFT WILL RESULT IN SCATTERED SLOW MOVING
STORMS WITH HIGH RAINFALL RATES. THE NEED FOR A FLASH FLOOD WATCH
APPEARS LIKELY FOR SOME AREAS WEST OF THE BLUE RIDGE FOR FRIDAY...
BUT WHICH COUNTIES TO INCLUDE IN A WATCH REMAINS UNCLEAR. WOULD LIKE
TO SEE HOW RAINFALL DEVELOPS THURSDAY AFTERNOON AND EVENING BEFORE
FINALIZING ANY DETAILS OF A POTENTIAL WATCH. IN ANY EVENT...RAINFALL
WILL DIMINISH IN INTENSITY DURING LATE EVENING AS INSTABILITY
DECREASES AND WINDS SHIFT MORE WESTERLY...RESULTING IN MORE OF A
DOWNSLOPE WINDFLOW.
THE SHORTWAVE TROUGH WILL PASS RAPIDLY ACROSS EASTERN CANADA
SATURDAY MORNING...GIVING A SOUTHWARD PUSH TO A STATIONARY FRONT
NEAR THE OHIO RIVER VALLEY. THE FRONT WILL ADVANCE TO AROUND THE
INTERSTATE 81 CORRIDOR BY SATURDAY EVENING...AND INTO THE CAROLINAS
BY SUNDAY EVENING. SIGNIFICANTLY DRIER AIR WILL LAG BEHIND THE COLD
FRONT HOWEVER...AND WILL EXPECT REDEVELOPMENT OF SHOWERS AND
THUNDERSTORMS FOR SATURDAY AND SUNDAY AFTERNOON/EVENING...MORE
SPOTTY IN NATURE...WITH COVERAGE CONCENTRATED MORE ACROSS THE
MOUNTAINS...ESPECIALLY IN OUR NORTHWEST FLOW UPSLOPE AREAS. BY LATE
SUNDAY NIGHT...DRIER AIR WILL WORK ITS WAY INTO THE MOUNTAINS...
LOWERING DEWPOINTS INTO THE UPPER 50S AND LOW 60S.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 400 PM EDT WEDNESDAY...
WITH THE UPPER RIDGE CONSOLIDATING AND MOVING TO THE FOUR CORNERS
REGION...TROUGHING WILL DEEPEN AND STRENGTHEN ACROSS THE EAST AND
MIDDLE ATLANTIC. WITH THE COOLER TEMPS AND LESS MOISTURE...SHOWERS
AND STORMS WILL BECOME LESS LIKELY AND SUPPRESSED SOUTH AS THE WEEK
WEARS ON. HOWEVER...CAN`T TOTALLY RULE OUT A FEW POP UP SHOWERS
REGIONWIDE WITH SUCH CHILLY TEMPS ALOFT FOR THIS TIME OF YEAR.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AS OF 740 AM EDT THURSDAY...
GOING TO SEE SKIES STAYING BKN-OVC TODAY WITH MOSTLY VFR TAKING
PLACE. OVERALL LOOKING AT RAIN SHOWERS AND STORMS MOVING INTO THE
WV MTNS LATER THIS MORNING THEN INCREASING INTO THE BCB/ROA AREA
BY MIDDAY. HAVE ADDED PREDOMINANT SHOWERS AT THESE SITES WITH
CONFIDENCE HIGH THAT BLF/LWB WILL GET MVFR VSBYS WITH MODERATE
SHOWERS AND ISOLATED THUNDER DURING THE AFTERNOON. LOOKS LIKE
DANVILLE WILL BE THE ONLY SITE THAT HAS A LOWER THREAT SO KEPT
EVEN VCTS OUT THERE.
THE SHOWERS WILL BE LINGERING AS ANOTHER WAVE MOVES INTO THE
MOUNTAINS LATER TONIGHT. WILL BE ENOUGH CLOUD COVER FOR MVFR TO
POTENTIAL IFR CIGS AT ALL SITES TONIGHT WITH POTENTIAL FOG IF
LOWER CLOUDS CLEAR OUT SOME.
BY FRIDAY-MONDAY A FRONTAL BOUNDARY WILL BE IN THE VICINITY TO
SEE MORE COVERAGE OF SHOWERS/STORMS AREA WIDE. THIS WILL KEEP
TERMINALS DEALING WITH DELAYS DUE TO STORMS...BUT OVER HALF THE
TIME...IT SHOULD BE VFR. DRIER AIR PUSHES INTO NORTH ON MONDAY
WITH SCATTERED CONVECTION STILL POSSIBLE ESPECIALLY IN THE SOUTH.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WP
NEAR TERM...WP
SHORT TERM...NF
LONG TERM...KM
AVIATION...DS/WP
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1032 AM CDT THU AUG 8 2013
.UPDATE...
BROKEN CLOUD DECK OVER THE SOUTHWEST AREA AND BROKEN CLOUD DECK OVER
NORTHWEST WISCONSIN EXPECTED TO MIX OUT LATER THIS MORNING. BASED ON
CURRENT MOVEMENT AND RAP FORECAST 700 MB RH...THE CLOUD DECK TO THE
NORTHWEST LOOKS TO ARRIVE IN NORTHWEST SAUK AND MARQUETTE COUNTY BY
18Z. BY THEN THE DECK IS EXPECTED TO BE SCATTERED OUT.
HIGHS IN THE MID TO UPPER 70S STILL SEEM REASONABLE. RIGHT NOW HAVE
COOLER TEMPS FORECAST NEAR THE LAKE WITH THE EAST WINDS...BUT
MKE...RAC...AND ENW HAVE ALREADY REACHED 70 DEGREES...SO WOULDN/T BE
SURPRISED IF THEY MADE IT TO THE MID 70S THERE AS WELL.
&&
.AVIATION/18Z TAFS/...
MVFR CIGS ACROSS THE WESTERN HALF OF THE FORECAST AREA WILL LIKELY
SCATTER LATE THIS MORNING...WITH BASE HEIGHTS ALSO RISING. VFR
CONDITIONS ARE THEN EXPECTED THIS AFTERNOON THROUGH FRIDAY. COULD
SEE A FEW SHOWERS LATE TONIGHT INTO FRIDAY...BUT ANY PRECIP WOULD
BE LIGHT.
&&
.PREV DISCUSSION... /ISSUED 330 AM CDT THU AUG 8 2013/
SHORT TERM...
TODAY AND TONIGHT...FORECAST CONFIDENCE...HIGH
DRY HIGH PRESSURE SETTLES OVER SOUTHERN WISCONSIN TODAY. KEPT
TEMPERATURES CLOSE TO PREVIOUS FORECAST AS 925 MB TEMPERATURES
SUPPORT UPPER 70S INLAND...WITH COOLER READINGS ALONG AND EAST OF
THE KETTLE MORAINE DUE TO LIGHT EAST WINDS OFF OF LAKE MICHIGAN.
NAM IS THE MOST PRODUCTIVE MODEL WITH PRECIPITATION ALONG SURFACE
TROUGH TONIGHT. IN SPITE OF A SHARPER MID LEVEL TROUGH AND
..FRONTOGENETIC FORCING AND Q-VECTOR CONVERGENCE RELATIVELY WEAK
AND WITH OTHER MODELS BARELY SHOWING ANY FORCING OR PCPN WILL HOLD
POPS TO SCATTERED. WILL KEEP PRECIPITATION TYPE AS RAIN SHOWERS WITH
MINIMAL ELEVATED CAPE...THOUGH NAM HAS 200 J/KG...AND EQUILIBRIUM
LEVELS BARELY MAKING IT TO -10C. WHILE A RUMBLE OF THUNDER NOT OUT
OF THE QUESTION TOO LOW A PROBABILITY TO MENTION.
NAM HAS MORE OF A 925 MB THERMAL RIDGE PASSING THRU OVERNIGHT AND IS
ABOUT 1C TO 2C WARMER THAN GFS OR ECMWF. HOWEVER ALL MODELS SHOWING
COOLING TEMPS THROUGH 06Z OR SO THEN LEVELING OUT WITH INCREASING
CLOUDS AND WEAK WAA WITH SWLY WINDS AHEAD OF TROUGH.
FRIDAY...FORECAST CONFIDENCE MEDIUM TO HIGH.
THE SURFACE TROUGH IS EXPECTED TO CLEAR SOUTHEAST WI BY 18Z FRIDAY.
KEPT THE SCATTERED SHOWERS IN THERE UNTIL THAT TIME. SOME MODELS
MAINTAIN THAT THE FORCING WILL NOT BE STRONG ENOUGH TO SUSTAIN ANY
SHOWERS INTO SOUTHEAST WI FRIDAY MORNING...SO LOWER CONFIDENCE IN
THE POP VALUES.
EXPECT SOME SUNSHINE TO RETURN IN THE AFTERNOON AS DRY AIR AND HIGH
PRESSURE SPREAD BACK INTO THE REGION. TEMPS WILL REBOUND INTO THE
UPPER 70S.
SATURDAY THROUGH SUNDAY...FORECAST CONFIDENCE HIGH.
SURFACE HIGH PRESSURE WILL SETTLE OVER THE GREAT LAKES REGION ONCE
AGAIN WHILE THE 500MB FLOW REMAINS IN A PERSISTENT PATTERN WITH
RIDGING OVER THE WEST AND SLIGHT TROUGHING OVER THE EAST. 925MB
TEMPS WILL DROP TO AROUND 14C EARLY SATURDAY MORNING OVER SOUTHERN
WI...WITH FRI NIGHT LOWS DROPPING INTO THE LOWER 50S. HIGHS ON
SATURDAY WILL BE IN THE MID 70S ONCE AGAIN AND THERE SHOULD BE
PLENTY OF SUNSHINE. TEMPS WILL BE COOLER NEAR THE SHORE DUE TO A
LAKE BREEZE.
SUNDAY WEATHER WILL BE QUIET...BUT EXPECT INCREASING MID AND HIGH
CLOUDS WITH ANOTHER SYSTEM APPROACHING. HIGHS WILL BE JUST A BIT
WARMER WITH RETURN FLOW AROUND THE DEPARTING SURFACE HIGH.
LONG TERM...
SUNDAY NIGHT AND BEYOND...FORECAST CONFIDENCE MEDIUM.
THE NEXT CHANCE FOR SHOWERS AND THUNDERSTORMS WILL BE SUNDAY NIGHT
AND MONDAY AS A 500MB TROUGH SWINGS DOWN ACROSS WISCONSIN. THERE IS
DECENT SUPPORT FROM AN 850MB LOW LEVEL JET NOSING INTO WI AND UPPER
DIVERGENCE ASSOCIATED WITH THE RIGHT ENTRANCE REGION OF AN UPPER
JET MOVING ACROSS THE STATE. THE MODELS ARE ALL SHOWING MORE QPF
WITH THIS FEATURE NOW...SO THERE IS INCREASING CONFIDENCE IN AT
LEAST SCATTERED STORM DEVELOPMENT.
SURFACE HIGH PRESSURE WILL SETTLE BACK INTO WISCONSIN BY MONDAY
EVENING AS THE UPPER LEVEL TROUGH AMPLIFIES OVER THE NORTHEAST AND
THE UPPER LEVEL RIDGE AMPLIFIES OVER THE SOUTHWEST. THE ECMWF IS
CONTINUING TO BRING AN UPPER TROUGH THROUGH WI ON WED WHICH WOULD
GENERATE SHOWERS...WHILE THE GFS MAINTAINS UPPER RIDGING. SINCE THE
00Z ECMWF CAME IN DRY ACROSS SOUTHERN WI WITH ONLY LIGHT QPF ACROSS
NORTHERN WI...OPTED TO REMOVE THE MENTION OF PRECIP FROM THE MKX
AREA PER COORDINATION WITH SURROUNDING OFFICES. TEMPS WILL REMAIN
STEADY AND JUST A LITTLE BELOW NORMAL THROUGH THE END OF NEXT WEEK.
AVIATION/12Z TAFS/...
ONCE ANY PATCHY MVFR FOG LIFTS BY MID-MORNING...EXPECTING VFR
CONDITIONS THROUGH THE REMAINDER OF THE FORECAST. WILL SEE BRIEF
MVFR CONDITIONS WITH SCATTERED RAIN SHOWERS AFTER 06Z...MAINLY FOR
KMSN.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...MEB/DDV
TODAY/TONIGHT AND AVIATION/MARINE...REM
FRIDAY THROUGH WEDNESDAY...MRC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
615 AM CDT THU AUG 8 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 344 AM CDT THU AUG 8 2013
AT 3 AM...A RIDGE OF HIGH PRESSURE EXTENDED FROM NORTHWEST
MINNESOTA SOUTHEAST INTO THE UPPER MISSISSIPPI RIVER VALLEY. THIS
HIGH IS PRODUCING LIGHT WINDS ACROSS THE REGION. LOOKING OUT
ACROSS THE MISSISSIPPI RIVER...ONE CAN SEE THAT THE BOUNDARY LAYER
EXTENDS UP TO THE RIDGE TOPS AND IT IS SLOWLY MOISTENING. THERE IS
ALSO SIGNS THAT A STRATUS DECK STARTING TO DEVELOP AROUND 500 TO
600 FEET ABOVE THE VALLEY FLOOR. THE TEMPERATURE AND DEW POINT
SPREAD AT LA CROSSE HAS FALLEN TO 1 DEGREE AND THE VISIBILITY HAS
RECENTLY DROPPED TO 4 MILES. THERE IS STILL SOME CONCERN THAT THE
CLOUDS STREAMING OFF OF THE CONVECTION OVER SOUTH DAKOTA MIGHT
KEEP WIDESPREAD VALLEY FOG FROM DEVELOPING...SO JUST WENT WITH
AREAS OF FOG AT THIS TIME. WILL CONTINUE TO MONITOR THROUGH THE
REMAINDER OF THE NIGHT FROM THE ROAD AND OUR CAM.
FROM TODAY THROUGH TONIGHT...A COLD FRONT...CURRENTLY EXTENDING FROM
DULUTH MINNESOTA TO PIERRE SOUTH DAKOTA...WILL MOVE SLOWLY
SOUTH THROUGH CENTRAL MINNESOTA AND NORTHERN WISCONSIN TODAY...AND
THROUGH MUCH OF OUR FORECAST AREA TONIGHT. AREAS ALONG AND NORTH
OF THE INTERSTATE 90 CORRIDOR WILL REMAIN IN THE RIGHT ENTRANCE
REGION OF A 110 KNOT JET. ONE CAN SEE THE UNDULATIONS ASSOCIATED
WITH THIS JET FROM ABERDEEN SOUTH DAKOTA EAST TO THE TWIN CITIES.
IN ADDITION...THE ML CAPES CLIMB UP TO 500 J/KG IN THIS SAME AREA
BETWEEN 08.21Z AND 09.03Z...AND WEAK 900 TO 700 MB FRONTOGENESIS.
THIS IS ENOUGH FORCING AND INSTABILITY FOR SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS TO DEVELOP. THE DETERMINISTIC MODELS ARE
MUCH MORE ROBUST WITH THEIR PRECIPITATION CHANCES THAN WHAT THE
ARW OR NMM WOULD SUGGEST. AS A RESULT...JUST WENT WITH A 20 TO
40 PERCENT CHANCE OF RAIN ASSOCIATED WITH THIS FRONT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 251 AM CDT THU AUG 8 2013
ON FRIDAY MORNING...THE COLD FRONT WILL MOVE SOUTH THROUGH
NORTHEAST IOWA AND SOUTHWEST WISCONSIN. AS THIS IS OCCURRING...IT
WILL BE LOSING THE 900 TO 800 MB FRONTOGENESIS...BUT THERE WILL
STILL BE WEAK 800 TO 600 MB FRONTOGENESIS. AS A RESULT...KEPT A
20 TO 30 PERCENT CHANCE RAIN ACROSS THIS AREA.
FROM LATE SATURDAY NIGHT INTO MONDAY MORNING...THE 08.00Z
ECMWF...GEM...AND GFS ARE NOW IN AGREEMENT WITH THEIR TIMING OF A
COLD FRONT THROUGH THE AREA. BOTH THE GEM AND GFS HAVE BEEN VERY
CONSISTENT WITH THE TIMING OF THIS FRONT AND ITS UPPER LEVEL SHORT
WAVE. MEANWHILE THE ECMWF HAS SLOWED ITS PASSAGE OF THIS FRONT BY
NEARLY 24 HOURS FROM ITS 07.12Z RUN. AS A RESULT...MUCH UNCERTAINTY
STILL REMAINS WITH THIS SYSTEM. DUE TO THIS...STAYED WITH THE ALL
BLEND PRECIPITATION CHANCES. WHILE THERE HAS BEEN ISSUES WITH
TIMING...THE MODELS HAVE BEEN CONSISTENTLY SHOWING THAT THERE WILL
BE RATHER LIMITED 925 TO 850 MB MOISTURE TRANSPORT INTO THE
AREA...AND THAT THE ML CAPES WILL REMAIN LESS THAN 1000 J/KG. WITH
THE 0-3 KM AND 0-6 KM MARGINAL SHEAR...NOT ANTICIPATING ANY SEVERE
WEATHER WITH THIS FRONTAL PASSAGE.
FROM TUESDAY NIGHT INTO WEDNESDAY...BOTH THE GFS AND ECMWF ARE
SHOWING THAT MUCH OF THE FORECAST AREA WILL BE STILL UNDER THE
INFLUENCE OF A CANADIAN HIGH PRESSURE SYSTEM. THIS TREND HAS
BEEN RATHER CONSISTENT DURING THE LAST 3 RUNS OF ECMWF. THE ONLY
PLACE THAT MAY SEE SOME SHOWERS AND THUNDERSTORMS IS NORTH OF THE
INTERSTATE 90 WHERE A SHORT WAVE MOVING THROUGH NORTHERN MINNESOTA
AND UPPER MICHIGAN MAY PRODUCE ENOUGH LIFT AND MOISTURE TRANSPORT
INTO THE AREA FOR SOME SCATTERED SHOWERS AND THUNDERSTORMS TO
DEVELOP. SINCE IT LOOKS DRY...REMOVED THE PRECIPITATION CHANCES
THAT THE ALL BLEND PRODUCED ACROSS THE ENTIRE AREA ON TUESDAY
NIGHT...AND ACROSS NORTHEAST IOWA...AND CENTRAL AND SOUTHWEST
WISCONSIN ON WEDNESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 615 AM CDT THU AUG 8 2013
VALLEY FOG STILL A CONCERN AT KLSE. WHILE SFC WINDS HAVE BEEN LIGHT
TO CALM...JUST OFF THE SFC THE WINDS CONTINUE TO STIR...HAMPERING
DENSE FOG FORMATION. RAP BUFKIT SOUNDINGS HAVE TRENDED LIGHTER WITH
THE NEAR SFC WINDS...AND WINDS WERE LIGHT AT THE NWS ARX
OFFICE...600 FT OFF THE VALLEY FLOOR. VISUAL INTO THE VALLEY SHOWS
SOME LOW STRATUS HANGING ABOVE THE MISSISSIPPI. T/TD SPREAD HAS HELD
AT 2 F THROUGH THE OVERNIGHT. STILL...SEE SOME POTENTIAL IT COULD
DROP TO 1SM OR SO IN THE 12-14Z TIME FRAME...AND IF SO...WOULD
QUICKLY MIX OUT AFTER THAT. WILL MONITOR TRENDS UP TO TAF ISSUANCE.
BCFG MIGHT MOST APPROPRIATE.
EXPECT INCREASING CLOUDS FROM THE WEST TODAY INTO
TONIGHT...ASSOCIATED WITH AN APPROACHING SFC TROUGH AND UPPER LEVEL
ENERGY. ENOUGH LIFT TO TRIGGER SCT SHRA/TS...ALTHOUGH THE TS WILL
LIKELY BE MORE ISOLATED AS INSTABILITY IS LIMITED AND CONFINED TO
THE LATE AFTERNOON/EVENING HOURS. WILL CONTINUE VCSH MENTION IN THE
TAFS FOR NOW...ALLOWING FOR INCREASED CONFIDENCE TO REFINE TIMING
AND CONDITIONAL WORDING AS NEEDED. BUFKIT SOUNDINGS AND RH FIELDS DO
POINT TO A LOWERING OF CIG DECK/SWITCH IN WINDS AS THE TROUGH SINKS
SOUTH OVERNIGHT. WILL TREND THIS WAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM....BOYNE
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1016 AM MDT THU AUG 8 2013
.UPDATE...
ISSUED AT 1015 AM MDT THU AUG 8 2013
SYNOPTIC SITUATION FOR LATER TODAY IS SIMILAR TO THAT OF
WEDNESDAY. PRECIPITATABLE WATER VALUES ARE SLIGHTLY HIGHER AND
STILL CONSIDERABLE MID AND UPPER LEVEL MOISTURE REMAINS OVER
MUCH OF THE CWA. LOW CLOUDS HAVE BEEN SLOWLY ERODING OVER THE
AREA THROUGH MID MORNING WITH ONLY THE AREAS BETWEEN K82V AND
KSNY AND KSNY AND KAIA STILL REPORTING LOW CLOUDS. THAT TREND
SHOULD CONTINUE SLOWLY THROUGH THE REST OF THE DAY. THE
TEMPERATURES WILL BE SIMILAR TODAY AND BELOW NORMAL IN MANY
AREAS. THOSE COOL TEMPERATURES AND THE EXISTING CLOUD COVER
WILL AGAIN ACT TO HINDER STORM ACTIVITY LATER TODAY. HOWEVER...
MAY BE MORE BREAKS IN THOSE CLOUDS TODAY AND ALREADY SHOWERS
ARE DEVELOPING OVER CARBON COUNTY. AT THIS TIME...BELIEVE THE
ACTIVITY WILL BE MORE A BIT WIDESPREAD THAN THAT OF WEDNESDAY
AS A WEAK MID LEVEL CIRCULATION WILL MOVE NEAR THE SOUTH PART
OF THE CWA AND SURFACE FORCING WILL PERSIST. STRONGER STORMS MAY
BE MORE POSSIBLE IN THE NORTH PART OF THE CWA WHERE TEMPERATURES
WILL BE WARMER. IN GENERAL...THE STRONGER STORMS WILL PRODUCE
HEAVY RAIN...BRIEF WIND GUSTS TO 45 MPH AND SMALL HAIL AND WILL
BE SLOWL MOVING. PREVIOUS FORECAST IS IN GOOD SHAPE AND IN A
RECENT UPDATE TOOK OUT THE EARLY MORNING FOG AND ADDED HEAVY
RAIN AND SMALL HAIL MENTION TO THE STORMS LATER TODAY.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY AFTERNOON)
ISSUED AT 312 AM MDT THU AUG 8 2013
AREAS OF FOG HAVE DEVELOPED ACROSS FAR SOUTHEAST WY THIS MORNING IN
RESPONSE TO MOIST SOUTH-TO-SOUTHEAST LLVL FLOW ALONG AND EAST OF THE
LARAMIE RANGE. VSBYS AT KCYS HAVE BEEN REDUCED TO ONE QUARTER OF A
MILE AT TIMES OVER THE PAST FEW HOURS...AND AREA WEBCAMS SHOW DENSE
FOG TO BE FAIRLY WIDESPREAD ACROSS CENTRAL AND EASTERN PORTIONS OF
LARAMIE COUNTY. MAIN QUESTION IS HOW LONG THIS FOG WILL LAST AS
WINDS MAY DEVELOP A SLIGHT SOUTHWEST COMPONENT EARLY THIS AM...WHICH
WOULD TEND TO SCOUR OUR EXISTING LLVL MOISTURE. ASSOCIATED -DZ COULD
ALSO LIMIT DENSE FOG POTENTIAL. LATEST HRRR RUNS STILL SHOW VERY LOW
VSBYS THROUGH ABOUT 15Z THOUGH...SO HAVE ISSUED A DENSE FOG ADVISORY
FOR THE I80 CORRIDOR BETWEEN THE SUMMIT AND NEBRASKA STATE LINE
THROUGH MID AM TO COVER AT LEAST THE NEAR TERM THREAT FOR HAZARDOUS
TRAVEL.
EVEN IF FOG DOES NOT PERSIST...LOW STRATUS SHOULD CREATES A FORECAST
HEADACHE FOR THU AFTN AND EVE. 11-3.9 MICROMETER IR CHANNEL SUGGESTS
LLVL CLOUDS ARE BECOMING RATHER WIDESPREAD FROM THE LARAMIE RANGE
EWD INTO THE WESTERN NE PANHANDLE. MIGHT BE TOUGH TO BURN OFF CLOUD
COVER TODAY AS EASTERLY UPSLOPE FLOW BECOMES ESTABLISHED OVER THE
HIGH PLAINS. GIVEN THIS AND 700 MILLIBAR TEMPS TO BE PROGGED ABOUT
1-2 DEG COOLER THAN WED...HAVE TRENDED A FEW DEGREES BELOW MOS GUID
FOR FCST HIGHS WHERE CLOUDS SHOULD BE THICKEST. NATURALLY THIS ALSO
LEADS TO QUESTIONS WITH INSTABILITY AND POSSIBLE CONVECTION LATER
IN THE DAY ON TOP OF AN ALREADY COMPLICATED SYNOPTIC SETUP.
A DIRTY UPPER-LEVEL RIDGE WILL BUILD INTO SOUTH CENTRAL WY THIS AFTN
WITH NUMEROUS MIDLVL DISTURBANCES LIKELY INTERACTING WITH MONSOONAL
MOISTURE IN THE 700-300 MILLIBAR LAYER. THIS...ALONG WITH UPPER-LEVEL
DIVERGENCE IN THE RIGHT REAR QUADRANT OF A MIDWEST US JET STREAK AND
UPSLOPING LLVL FLOW SHOULD CONTRIBUTE TO SUFFICIENT LIFT FOR SHOWER
AND TSTM DEVELOPMENT LATER TODAY. THE BEST DYNAMICS APPEAR TO DROP
TO THE SOUTH WITH A STRONGER WAVE EVIDENT ON WATER VAPOR SATELLITE
OVER EASTERN UT AND WESTERN CO...WHICH COULD LIMIT OVERALL COVERAGE
OF PCPN IN OUR CWA. ESSENTIALLY BETWEEN SYSTEMS...FLOW ALOFT SHOULD
BE WEAK WITH ONLY AROUND 10-15 KTS OF 700-500 MILLIBAR FLOW. LESS
THAN 30 KTS OF EFFECTIVE SHEAR SHOULD KEEP SEVERE STORMS AT BAY...
EVEN IF THE MUCH MORE UNSTABLE NAM WOULD VERIFY WITH SURFACE CAPES
IN EXCESS OF 1500 J/KG. THINKING INSTABILITY WILL BE MODEST AT BEST
THOUGH WITH LIMITED DAYTIME HEATING...BUT MIDLVL COOLING WILL YIELD
SUFFICIENT ELEVATED INSTABILITY FOR TSTM DEVELOPMENT. OVERALL THREAT
FROM CONVECTION WILL BE HEAVY RAIN FROM SLOW MOVING STORMS...THOUGH
PWATS ARE NOT PARTICULARLY HIGH WITH SOME MOISTURE BEING ROBBED BY
THE SYSTEM TO THE SOUTH.
TRYING NOT TO SOUND LIKE A BROKEN RECORD...PERSISTENCE IS THE NAME
OF THE GAME AS WE HEAD INTO FRIDAY. SEVERAL WEAK DISTURBANCES ARE
LIKELY TO TRAVERSE THE FLOW ALONG THE EDGE OF THE CENTRAL ROCKIES
RIDGE...MOST OF WHICH ARE TOO WEAK TO ACCURATELY PREDICT WITH ANY
REASONABLE DEGREE OF ACCURACY. WITH ABUNDANT SUBTROPICAL MOISTURE
REMAINING IN PLACE OVER THE AREA...OVERALL PATTERN FAVORS ANOTHER
COOL DAY WITH SCATTERED SHOWERS AND STORMS WITH CONTINUED UPSLOPE
FLOW IN THE LLVLS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 342 AM MDT THU AUG 8 2013
ACTIVE WEATHER PATTERN TO REMAIN IN PLACE THROUGH THE EXTENDED
FORECAST PERIOD. THE ONLY POTENTIAL CHANGE IS FOR THE UPPER LEVEL
RIDGE CURRENTLY OVER THE ROCKIES TO EXPAND NORTHWARD. BOUTS OF
MONSOON MOISTURE SHOULD CONTINUE TO SNEAK UNDER THE RIDGE AND
INFLUENCE THE FORECAST AREA WITH CHANCES FOR AFTERNOON AND EVENING
SHOWERS AND THUNDERSTORMS...WHILE TEMPERATURES SHOULD BE NEAR TO
SLIGHTLY ABOVE NORMAL THROUGH THE PERIOD. WITH THE RIDGE IN PLACE
UPPER LEVEL WINDS WILL BE ON THE LIGHT SIDE WHICH SHOULD SERVE TO
MINIMIZE SEVERE WEATHER CHANCES. HIGH TEMPERATURES WILL MAINLY BE
IN THE 80S WITH LOWS IN THE 50S FOR AREAS OUTSIDE OF THE
MOUNTAINS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY MORNING)
ISSUED AT 1015 AM MDT THU AUG 8 2013
VISIBILITIES HAVE IMPROVED OVER THE SOUTH PART OF THE CWA AND
AS OF 15Z WERE VFR. STILL AREAS OF LOW CLOUDS BETWEEN K82V
AND KSNY AND KSNY AND KAIA. THE LOW CLOUDS SHOULD CONTINUE TO
SLOWLY ERODE AND CEILINGS LIFT WITH VFR CEILINGS BY THE MID TO
LATE AFTERNOON OVER THOSE AREAS.
A SCATTERED COVERAGE OF AFTERNOON AND EVENING SHOWERS WILL
AFFECT THE CWA AND WILL PRODUCE BRIEF MVFR CEILINGS AND
VISIBILITIES IN RAIN ALONG WITH GUSTY WINDS. THE MOUNTAINS MAY
BE OBSCURED AT TIMES.
AREAS OF LOW CLOUDS AND FOG WILL REDEVELOP OVER MAINLY THE
SOUTHERN PANHANDLE AFTER 08Z AND PERSIST THROUGH 15Z FRIDAY.
THEN ANOTHER ROUND OF SCATTERED SHOWERS AND STORMS WILL AFFECT
MUCH OF THE CWA FRIDAY AFTERNOON AND EVENING.
&&
.FIRE WEATHER...
ISSUED AT 312 AM MDT THU AUG 8 2013
FIRE WEATHER CONCERNS WILL BE MINIMAL OVER THE NEXT FEW DAYS AS
MONSOON MOISTURE REMAINS IN PLACE OVER THE REGION. TEMPERATURES
WILL BE NORMAL OR SLIGHTLY BELOW WITH AT LEAST SCATTERED SHOWERS
AND STORMS EACH AFTERNOON AND EVENING THROUGH FRIDAY. DRYING IS
EXPECTED ACROSS WESTERN CARBON AND CONVERSE COUNTIES DURING THE
WEEKEND WITH AFTERNOON RELATIVE HUMIDITY VALUES FALLING BELOW 15
PERCENT. HOWEVER WINDS ARE EXPECTED TO REMAIN BELOW THE CRITICAL
THRESHOLDS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...WEILAND
SHORT TERM...HAMMER
LONG TERM...LIEBL
AVIATION...WEILAND
FIRE WEATHER...HAMMER
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
533 AM MDT THU AUG 8 2013
.SHORT TERM...(TODAY THROUGH FRIDAY AFTERNOON)
ISSUED AT 312 AM MDT THU AUG 8 2013
AREAS OF FOG HAVE DEVELOPED ACROSS FAR SOUTHEAST WY THIS MORNING IN
RESPONSE TO MOIST SOUTH-TO-SOUTHEAST LLVL FLOW ALONG AND EAST OF THE
LARAMIE RANGE. VSBYS AT KCYS HAVE BEEN REDUCED TO ONE QUARTER OF A
MILE AT TIMES OVER THE PAST FEW HOURS...AND AREA WEBCAMS SHOW DENSE
FOG TO BE FAIRLY WIDESPREAD ACROSS CENTRAL AND EASTERN PORTIONS OF
LARAMIE COUNTY. MAIN QUESTION IS HOW LONG THIS FOG WILL LAST AS
WINDS MAY DEVELOP A SLIGHT SOUTHWEST COMPONENT EARLY THIS AM...WHICH
WOULD TEND TO SCOUR OUR EXISTING LLVL MOISTURE. ASSOCIATED -DZ COULD
ALSO LIMIT DENSE FOG POTENTIAL. LATEST HRRR RUNS STILL SHOW VERY LOW
VSBYS THROUGH ABOUT 15Z THOUGH...SO HAVE ISSUED A DENSE FOG ADVISORY
FOR THE I80 CORRIDOR BETWEEN THE SUMMIT AND NEBRASKA STATE LINE
THROUGH MID AM TO COVER AT LEAST THE NEAR TERM THREAT FOR HAZARDOUS
TRAVEL.
EVEN IF FOG DOES NOT PERSIST...LOW STRATUS SHOULD CREATES A FORECAST
HEADACHE FOR THU AFTN AND EVE. 11-3.9 MICROMETER IR CHANNEL SUGGESTS
LLVL CLOUDS ARE BECOMING RATHER WIDESPREAD FROM THE LARAMIE RANGE
EWD INTO THE WESTERN NE PANHANDLE. MIGHT BE TOUGH TO BURN OFF CLOUD
COVER TODAY AS EASTERLY UPSLOPE FLOW BECOMES ESTABLISHED OVER THE
HIGH PLAINS. GIVEN THIS AND 700 MILLIBAR TEMPS TO BE PROGGED ABOUT
1-2 DEG COOLER THAN WED...HAVE TRENDED A FEW DEGREES BELOW MOS GUID
FOR FCST HIGHS WHERE CLOUDS SHOULD BE THICKEST. NATURALLY THIS ALSO
LEADS TO QUESTIONS WITH INSTABILITY AND POSSIBLE CONVECTION LATER
IN THE DAY ON TOP OF AN ALREADY COMPLICATED SYNOPTIC SETUP.
A DIRTY UPPER-LEVEL RIDGE WILL BUILD INTO SOUTH CENTRAL WY THIS AFTN
WITH NUMEROUS MIDLVL DISTURBANCES LIKELY INTERACTING WITH MONSOONAL
MOISTURE IN THE 700-300 MILLIBAR LAYER. THIS...ALONG WITH UPPER-LEVEL
DIVERGENCE IN THE RIGHT REAR QUADRANT OF A MIDWEST US JET STREAK AND
UPSLOPING LLVL FLOW SHOULD CONTRIBUTE TO SUFFICIENT LIFT FOR SHOWER
AND TSTM DEVELOPMENT LATER TODAY. THE BEST DYNAMICS APPEAR TO DROP
TO THE SOUTH WITH A STRONGER WAVE EVIDENT ON WATER VAPOR SATELLITE
OVER EASTERN UT AND WESTERN CO...WHICH COULD LIMIT OVERALL COVERAGE
OF PCPN IN OUR CWA. ESSENTIALLY BETWEEN SYSTEMS...FLOW ALOFT SHOULD
BE WEAK WITH ONLY AROUND 10-15 KTS OF 700-500 MILLIBAR FLOW. LESS
THAN 30 KTS OF EFFECTIVE SHEAR SHOULD KEEP SEVERE STORMS AT BAY...
EVEN IF THE MUCH MORE UNSTABLE NAM WOULD VERIFY WITH SURFACE CAPES
IN EXCESS OF 1500 J/KG. THINKING INSTABILITY WILL BE MODEST AT BEST
THOUGH WITH LIMITED DAYTIME HEATING...BUT MIDLVL COOLING WILL YIELD
SUFFICIENT ELEVATED INSTABILITY FOR TSTM DEVELOPMENT. OVERALL THREAT
FROM CONVECTION WILL BE HEAVY RAIN FROM SLOW MOVING STORMS...THOUGH
PWATS ARE NOT PARTICULARLY HIGH WITH SOME MOISTURE BEING ROBBED BY
THE SYSTEM TO THE SOUTH.
TRYING NOT TO SOUND LIKE A BROKEN RECORD...PERSISTENCE IS THE NAME
OF THE GAME AS WE HEAD INTO FRIDAY. SEVERAL WEAK DISTURBANCES ARE
LIKELY TO TRAVERSE THE FLOW ALONG THE EDGE OF THE CENTRAL ROCKIES
RIDGE...MOST OF WHICH ARE TOO WEAK TO ACCURATELY PREDICT WITH ANY
REASONABLE DEGREE OF ACCURACY. WITH ABUNDANT SUBTROPICAL MOISTURE
REMAINING IN PLACE OVER THE AREA...OVERALL PATTERN FAVORS ANOTHER
COOL DAY WITH SCATTERED SHOWERS AND STORMS WITH CONTINUED UPSLOPE
FLOW IN THE LLVLS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 342 AM MDT THU AUG 8 2013
ACTIVE WEATHER PATTERN TO REMAIN IN PLACE THROUGH THE EXTENDED
FORECAST PERIOD. THE ONLY POTENTIAL CHANGE IS FOR THE UPPER LEVEL
RIDGE CURRENTLY OVER THE ROCKIES TO EXPAND NORTHWARD. BOUTS OF
MONSOON MOISTURE SHOULD CONTINUE TO SNEAK UNDER THE RIDGE AND
INFLUENCE THE FORECAST AREA WITH CHANCES FOR AFTERNOON AND EVENING
SHOWERS AND THUNDERSTORMS...WHILE TEMPERATURES SHOULD BE NEAR TO
SLIGHTLY ABOVE NORMAL THROUGH THE PERIOD. WITH THE RIDGE IN PLACE
UPPER LEVEL WINDS WILL BE ON THE LIGHT SIDE WHICH SHOULD SERVE TO
MINIMIZE SEVERE WEATHER CHANCES. HIGH TEMPERATURES WILL MAINLY BE
IN THE 80S WITH LOWS IN THE 50S FOR AREAS OUTSIDE OF THE
MOUNTAINS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 412 AM MDT THU AUG 8 2013
WIDESPREAD LOW CLOUDS AND FOG WILL BE FOUND OVER SOUTHEAST WYOMING
MAINLY EAST OF THE LARAMIE RANGE EARLY THIS MORNING WITH AREAS OF
DENSE FOG. CEILINGS WILL DROP TO ONLY A FEW HUNDRED FEET AGL WITH
VISIBILITIES 1/4 MILE OR LESS AT TIMES. FOG WILL ALSO BE FOUND
OVER PORTIONS OF THE NEBRASKA PANHANDLE. FOG WILL BEGIN TO LIFT
AFTER SUNRISE BUT SOME FOG AND LOW CLOUDS TO HANG THROUGH LATE
THIS MORNING. ATTENTION TURNS TO CHANCES FOR THUNDERSTORMS THIS
AFTERNOON. EXPECTING SCATTERED SHOWERS AND THUNDERSTORMS
DEVELOPING THIS AFTERNOON BUT ACTUAL COVERAGE WILL DEPEND ON HOW
LONG THE FOG HOLDS THIS MORNING. GUSTY WINDS AND SMALL HAIL
POSSIBLE WITH SOME THUNDERSTORMS THIS AFTERNOON AND EVENING. FOG
MAY REDEVELOP AFTER MIDNIGHT TONIGHT IN THE EAST.
&&
.FIRE WEATHER...
ISSUED AT 312 AM MDT THU AUG 8 2013
FIRE WEATHER CONCERNS WILL BE MINIMAL OVER THE NEXT FEW DAYS AS
MONSOON MOISTURE REMAINS IN PLACE OVER THE REGION. TEMPERATURES
WILL BE NORMAL OR SLIGHTLY BELOW WITH AT LEAST SCATTERED SHOWERS
AND STORMS EACH AFTERNOON AND EVENING THROUGH FRIDAY. DRYING IS
EXPECTED ACROSS WESTERN CARBON AND CONVERSE COUNTIES DURING THE
WEEKEND WITH AFTERNOON RELATIVE HUMIDITY VALUES FALLING BELOW 15
PERCENT. HOWEVER WINDS ARE EXPECTED TO REMAIN BELOW THE CRITICAL
THRESHOLDS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...DENSE FOG ADVISORY UNTIL 9 AM MDT THIS MORNING FOR WYZ117>119.
NE...NONE.
&&
$$
SHORT TERM...HAMMER
LONG TERM...LIEBL
AVIATION...LIEBL
FIRE WEATHER...HAMMER
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
254 AM CDT SAT AUG 10 2013
.DISCUSSION...
249 PM CDT
SYNOPSIS...A COLD FRONT PASSES THROUGH THE REGION TONIGHT WHILE AN
UPPER LEVEL LOW SHIFTS EAST INTO QUEBEC TONIGHT. COOL CONDITIONS
CONTINUE WITH A CHANCE OF RAIN EARLY NEXT WEEK.
REST OF TODAY THROUGH SATURDAY...
A COLD FRONT EXTENDS FROM GAYLORD MI THROUGH DUBUQUE IOWA AND IT
WILL SLOWLY PASS THROUGH THE REGION TONIGHT. ISOLATED SHOWERS WILL
DEVELOP ALONG THE FRONT THIS AFTERNOON...WITH A FEW ALREADY FORMING
WEST OF THE CWA IN FAR NW IL AND IA. KEPT THUNDER OUT OF THE
FORECAST THIS AFTERNOON AS CAPE IS 800 J/KG OR LESS ACROSS THE
REGION ACCORDING TO THE LATEST LAPS ANALYSIS. AS SUCH MAY SEE A
LIGHTNING STRIKE OR TWO BUT OVERALL JUST EXPECTING SPOTTY SHOWERS
THIS AFTERNOON AND EVENING. CLOUDS WILL THIN ALLOWING MIN TEMPS TO
FALL INTO THE UPPER 50S TO LOW 60S TONIGHT.
RELATIVELY ZONAL FLOW SETS UP ALOFT TOMORROW WHILE THE UPPER LEVEL
RIDGE BUILDS OVER THE WESTERN U.S. SURFACE HIGH PRESSURE ARRIVES
FROM THE NORTHWEST RESULTING IN SCATTERED CLOUD COVER AND TEMPS
AROUND 80. A LAKE BREEZE WILL KEEP HIGH TEMPS DOWNTOWN IN THE MID
70S.
SUNDAY THROUGH MONDAY NIGHT...
A SHORTWAVE PASSES OVER WISCONSIN LATE SATURDAY NIGHT INTO SUNDAY
MORNING PRODUCING AN AREA OF SHOWERS. PUT A SLIGHT CHANCE OF SHRA
ACROSS THE IL/WI STATE LINE DURING THE DAY ON SUNDAY BUT EXPECTING
THE MAJORITY OF PRECIP TO REMAIN CLOSER TO THE IMPULSE IN WI. MAY
ALSO SEE A FEW THUNDERSTORMS AS GUIDANCE SUGGESTS WE MAY HAVE AROUND
1500 J/KG OVER FAR NORTHERN IL SUNDAY AFTERNOON. BUT ONCE
AGAIN...THE BETTER FORCING WILL BE CLOSER TO THE SHORTWAVE IN WI SO
THINKING THE MORE WIDESPREAD THUNDERSTORM ACTIVITY WILL BE TO OUR
NORTH. PWAT VALUES WILL BE BTWN 1 AND 1.5 INCHES SO MODERATE TO
ISOLATED HEAVY SHOWERS ARE POSSIBLE.
AN UPPER LEVEL LOW ROTATES OVER HUDSON BAY AND NORTHERN ONTARIO
SUNDAY EVENING AND NIGHT...AND THE TROUGH AXIS PUSHES THROUGH THE
REGION MONDAY. AS THE TROUGH AXIS APPROACHES...SHOWERS AND
THUNDERSTORMS PUSH SOUTH THROUGH THE CWA WITH THE BEST FOCUS OF
PRECIP ALONG AND NORTH OF I-80 BY MONDAY MORNING.
HOWEVER...EXPECTING A CHANCE FOR PRECIP ACROSS THE ENTIRE CWA DURING
THE DAY ON MONDAY. 1-2 INCHES OF PWAT IS EXPECTED SO HOPEFULLY WE
WILL SEE THE SOAKING RAIN THAT IS NEEDED IN MANY PARTS OF THE CWA.
RAIN SHIFTS TO THE SOUTHEAST AHEAD OF THE TROUGH AXIS MONDAY NIGHT.
TEMPS REMAIN BELOW NORMAL WITH HIGHS AROUND 80...EXPECT COOLER BY
THE LAKE...AND LOWS IN THE LOW 60S.
EXTENDED...TUESDAY THROUGH NEXT THURSDAY...
THE UPPER LEVEL TROUGH SHIFTS EAST INTO QUEBEC USHERING IN ANOTHER
PUSH OF COOL AIR. NORTHWEST FLOW IS OVER THE AREA THROUGH THE END
OF NEXT WEEK AND A SURFACE HIGH MOVES OVER THE REGION TUESDAY
AFTERNOON. THE HIGH STAYS WITH US THROUGH THE REST OF NEXT WEEK
WITH DRY AND COOL CONDITIONS EXPECTED.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* NORTH-NORTHWEST WINDS TURNING NORTHEAST SOMETIME THIS MORNING.
MDB
//DISCUSSION...UPDATED 06Z...
A WEAK COOL FRONT CONTINUES TO SLOWLY MOVE SOUTHEAST ACROSS THE
TERMINALS EARLY TONIGHT. WINDS BEHIND THE FRONT ARE TURNING
NORTHWESTERLY...BUT THIS IS TAKING SOME TIME TO OCCUR WITH
MDW/DPA/GYY HOLDING WNW. EXPECT THESE SITES TO TURN NNW WITH TIME
OVERNIGHT WITH SPEEDS AROUND 6 KT OR LESS. LOWER LEVEL VFR CLOUDS
WILL STEADILY MOVE OUT OF THE AREA WITH A FAIRLY DENSE CIRRUS
SHIELD LINGERING THROUGH THE NIGHT BEFORE DEPARTING TOWARD
DAYBREAK. LATEST OBSERVED TRENDS AND GUIDANCE SUPPORTS A SHIFT TO
NORTHEAST WINDS AT ORD/MDW DURING THE MID/LATE MORNING HOURS SO
HAVE ADJUSTED TIMING FOR THIS IN THE TAFS. WINDS LOOK TO BECOME
LIGHT AND VARIABLE OR CALM THIS EVENING AS HIGH PRESSURE MOVES
RIGHT OVERHEAD.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN WINDS TURNING NORTHEAST WITH MEDIUM
CONFIDENCE IN TIMING.
MDB
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
* SUNDAY...CHANCE OF TSRA TOWARD EVENING.
* MONDAY...CHANCE OF TSRA. MVFR POSSIBLE. LAKE BREEZE/WIND SHIFT.
* TUESDAY THROUGH THURSDAY...DRY/VFR.
&&
.MARINE...
252 AM CDT
DEEPENING LOW PRESSURE IS MOVING EASTWARD ACROSS EASTERN QUEBEC THIS
MORNING. ONE AREA OF HIGH PRESSURE IS SPREAD ACROSS THE OHIO RIVER
VALLEY AND THE SOUTHEAST U.S. WHILE ANOTHER AREA OF HIGH PRESSURE IS
SPREAD FROM THE CANADIAN PRAIRIES TO THE CENTRAL PLAINS. THIS
NORTHERN HIGH WILL MOVE SOUTHEASTWARD AND ACROSS CENTRAL ILLINOIS
TONIGHT. A TROUGH OF LOW PRESSURE WILL THEN MOVE ACROSS THE AREA
EARLY MONDAY WITH STRONG CANADIAN HIGH PRESSURE BUILDING IN BEHIND
IT INTO TUESDAY. AS A RESULT...SOUTHERLY WINDS AHEAD OF THE FRONT
MONDAY WILL TURN NORTHERLY LATER MONDAY INTO TUESDAY AS LOW PRESSURE
BEGINS TO DEEPEN ACROSS NORTHERN NEW ENGLAND. EXPECT THAT WINDS WILL
COME UP TO AROUND 20 KT MONDAY NIGHT AND TUESDAY AS THE PRESSURE
GRADIENT TIGHTENS AND A PUSH OF COOLER AIR SPREADS IN. THIS WILL
KICK WAVES UP TO NEAR SMALL CRAFT ADVISORY CRITERIA BEFORE SUBSIDING
TUESDAY NIGHT OR WEDNESDAY MORNING. HIGH PRESSURE WILL THEN BE OVER
THE AREA WEDNESDAY THROUGH THE REST OF NEXT WEEK.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
[top]
Area Forecast Discussion
National Weather Service Lincoln IL
240 AM CDT Sat Aug 10 2013
.DISCUSSION...
ISSUED 240 AM CDT Sat Aug 10 2013
SHORT TERM...Today through Monday
Weak secondary cold front will continue to drop southward and
dissipate across central Illinois today, while main synoptic
boundary remains stalled from the Mid-Atlantic states W/SW into
the Southern Plains. Periods of showers and thunderstorms will
accompany the primary front, but will stay well south of the
KILX CWA. High-res HRRR hints at a few showers potentially
developing ahead of a weak short-wave across northern Indiana this
afternoon, but these would likely remain outside of central
Illinois as well. End result will be a partly to mostly sunny day
with high temperatures in the lower 80s.
High pressure will build southward into the region tonight, providing
cool/dry weather with lows dropping into the 50s. With high pressure
overhead, another pleasant summer day is in store for Sunday with
highs reaching the lower to middle 80s. Once the high begins to
slide off to the east, a light southerly return flow will allow a
warmer/more humid airmass to trickle back into the area Sunday
night into Monday. Forecast soundings indicate precipitable water
values climbing back over 1.50 inches while surface dewpoints
reach the 70-degree mark by Monday afternoon. Meanwhile...another
deep upper low will rotate southward from Hudson Bay, pushing a cold
front into Illinois. This front will interact with the increasingly
moist airmass to produce scattered showers and thunderstorms,
particularly during the afternoon and evening. Due to only modest
instability with CAPE values around 1500J/kg and best upper
support remaining further north across the Great Lakes, am not
expecting widespread convection. Will therefore maintain just
chance pops Monday into Monday night.
LONG TERM...Tuesday through Friday
Frontal boundary sags southward early next week, with model consensus
taking it south of the Ohio River by Tuesday morning. Will hold on
to just a slight chance POP across the far SE CWA into Tuesday in
case front slows. Otherwise, another cool/dry Canadian airmass
will settle southward into the region behind the departing front
for the remainder of next week. With upper flow becoming
prominently northwesterly, any potential MCS activity will likely
be shunted well W/SW of Illinois, leading to a dry forecast
through Friday. Temps next week will remain below normal, with
afternoon highs generally in the upper 70s/lower 80s and overnight
lows in the upper 50s/lower 60s.
BARNES
&&
.AVIATION...
ISSUED 1150 PM CDT Fri Aug 9 2013
Generally quiet/VFR aviation weather conditions expected across the
central Illinois terminals through the 06Z TAF valid time,
although there may be patchy MVFR fog overnight tonight. A weak
frontal boundary will settle south of the area tonight, allowing
high pressure to build into the area for Saturday. The majority of
the cloud cover will be of the mid/high level variety, but
scattered VFR level CU should develop with diurnal heating
Saturday.
BAK
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
205 AM EDT SAT AUG 10 2013
.UPDATE...
ISSUED AT 200 AM EDT SAT AUG 10 2013
HAVE ADJUSTED THE POP AND WX GRIDS TO REFLECT THE ONGOING CONVECTION
IN THE FAR NORTH AND SOME NEWER CELLS GOING UP IN THE CUMBERLAND
VALLEY. RUN TO RUN CONSISTENCY FROM THE HRRR MAKES ITS SOLUTION
QUESTIONABLE SO HAVE ONLY PARTIALLY SHADED THE FORECAST TOWARD ITS
IDEAS THAT ARE IN LINE WITH THE 00Z NAM12 AND CURRENT RADAR SCOPE.
ALSO...FINE TUNED THE T AND TD GRIDS PER THE LATEST OBS AND TRENDS.
UPDATES HAVE BEEN SENT TO THE NDFD AND WEB SERVERS WITH A FRESHENED
ZFP TO FOLLOW.
UPDATE ISSUED AT 720 PM EDT FRI AUG 9 2013
SHOWERS AND STORMS CONTINUE TO EXPAND ACROSS CENTRAL AND SOUTHERN
KENTUCKY WITH IMPRESSIVE RAINFALL RATES NEAR 2 INCHES PER HOUR FAIRLY
COMMON. GIVEN SOME LOWER FLASH FLOOD GUIDANCE VALUES IN SOME
AREAS...THIS COULD MEAN WE MAY EXCEED FLASH FLOOD GUIDANCE IN SOME
PLACES. THUS...FLOODING WILL CONTINUE TO BE A THREAT THROUGH THIS
EVENING. OPTING TO NOT FLIP FLOP ON ANY WATCH AND JUST ISSUE ANY
WARNINGS AS NEEDED. LOOKS LIKE THE SOUTHERN HALF OF THE CWA WILL BE
UNDER THE BIGGEST THREAT FOR ANY FLOODING. STILL UNCERTAIN WITH HOW
THE REST OF THE NIGHT WILL PAN OUT...BUT THE NEXT SEVERAL HOURS LOOKS
VERY ACTIVE WITH LOTS OF RAIN FOR SOME OF THE AREA. WILL UPDATE GRIDS
TO REFLECT THE BETTER RAIN CHANCES ACROSS THE SOUTH.
UPDATE ISSUED AT 606 PM EDT FRI AUG 9 2013
WITH THE FLOOD WATCH NOW HISTORY...SHOWERS AND STORMS ARE RAMPING UP
ACROSS SOUTHERN AND CENTRAL KENTUCKY. DO NOT HAVE A REAL GOOD FEEL
FOR HOW THINGS WILL EVOLVE THIS EVENING. MODELS ARE ALL HANDLING THIS
SYSTEM VERY POORLY...BUT BASED ON CURRENT RADAR TRENDS...IT LOOKS
LIKE SOME BETTER RAIN SHOULD MOVE INTO MUCH OF EASTERN KENTUCKY INTO
THE MID TO LATE EVENING HOURS. SOME OF THIS MAY WEAKEN AS WE LOSE THE
BETTER INSTABILITY...BUT WITH THE FRONTAL BOUNDARY PUSHING INTO
NORTHERN KENTUCKY...WE MAY SEE STUFF AT LEAST IN THE NORTH STAY
ACTIVE WELL INTO THE NIGHT. AGAIN...UPDATED WILL BE NEEDED THROUGH
THE NIGHT AS PRECIPITATION TRENDS BECOME BETTER DEFINED. FOR
NOW...GOING TO UPDATE THE NEXT FEW HOURS AND BLEND INTO THE OLD
FORECAST. MAY NEED TO WATCH THE POTENTIAL FOR FLOODING GIVEN THE
IMPRESSIVE RAINFALL RATES BEING RECEIVED UPSTREAM OVER SOUTH CENTRAL
KENTUCKY. GRIDS HAVE BEEN SENT TO THE NDFD.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 410 PM EDT FRI AUG 9 2013
A LINE OF CONVECTION WAS AT THE NORTHERN EDGE OF THE FORECAST AREA AT
MID AFTERNOON...WITH ADDITIONAL SCATTERED SHOWERS/THUNDERSTORMS OVER
TN. MOST OF THE FORECAST AREA WAS QUIET...ALTHOUGH A FEW SHOWERS WERE
STRUGGLING TO GET GOING. FORECAST SOUNDINGS LOOKED FAVORABLE FOR
ACTIVITY LATE TODAY...AND WILL CONTINUE WITH THIS IN THE FORECAST.
HOWEVER...THE BEST SHOT AT RAIN LOOKS LIKE IT WILL BE TONIGHT INTO
EARLY SATURDAY. MODELS IN GENERAL HAVE POINTED TO THIS...BUT HAVE
SHOWN POOR AGREEMENT/CONSISTENCY ON THE POTENTIAL FOR HEAVY PRECIP.
IN LIGHT OF THIS AND HISTORY SINCE THE WATCH WAS ISSUED...WILL CANCEL
THE WATCH WHICH WAS OTHERWISE SET TO EXPIRE AT 8 PM. WE ARE NOT
COMPLETELY OUT OF THE WOODS WITH THE THREAT...BUT CONFIDENCE IS NOT
THERE TO WARRANT AN EXTENSION.
THE FRONTAL BOUNDARY WHICH HAS BEEN HUNG UP JUST TO OUR NORTH MAY
SINK A BIT FURTHER SOUTH ON SATURDAY NIGHT...AND
SHOWERS/THUNDERSTORMS WILL STILL BE POSSIBLE. HOWEVER...GUIDANCE IN
GENERAL IS LIGHTER ON PRECIP AND MOS IS LOWER ON POPS...AND FOLLOWED
THEIR LEAD FOR THE FORECAST.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 410 PM EDT FRI AUG 9 2013
PRETTY GOOD AGREEMENT BETWEEN THE LONG TERM MODELS. THE CONSENSUS IS
FOR A LARGE UPPER LEVEL TROUGH TO MOVE ACROSS THE NORTHERN CONUS
FROM SUNDAY ONWARD...WITH ITS ATTENDANT SURFACE COLD FRONT GETTING
DRAGGED ACROSS THE OHIO AND TENNESSEE VALLEYS. BASED ON THE OVERALL
MOISTURE DISTRIBUTION...BOTH AT THE SURFACE AND ALOFT...ACROSS THE
AREA...SCATTERED SHOWERS AND STORMS WILL BE ON TAP DURING FRONTAL
PASSAGE. THE FRONT COULD GET HUNG UP A BIT AS IT ENCOUNTERS THE
APPALACHIAN MOUNTAINS...AND AS A RIDGE STUBBORNLY REMAINS IN PLACE
OFF THE SOUTHEAST COAST. A SURFACE RIDGE WILL FINALLY STRENGTHEN
ENOUGH BY THE END OF THE WEEK TO PUSH THE FRONT...AND ITS
PRECIPITATION OUT OF THE AREA. TEMPERATURES DURING THE UPCOMING WORK
WEEK WILL RUN AT OR SLIGHTLY BELOW NORMAL DUE TO EXTENSIVE CLOUD
COVER AND PERIODIC PRECIPITATION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 205 AM EDT SAT AUG 10 2013
DEVELOPING SHOWERS AND THUNDERSTORMS MAY AFFECT SOME OF THE TAF SITES
DURING THE NEXT FEW HOURS...BUT MOST WILL STAY IN THE CLEAR...ASIDE
FROM SOME PATCHY...MVFR FOG. EXPECT ADDITIONAL SHOWERS AND
THUNDERSTORMS TO TAKE SHAPE LATER IN THE MORNING. ANY OF THESE
STORMS...INTO THE DAY SATURDAY...WILL DROP VISIBILITIES AND CEILINGS
TO MVFR OR BRIEFLY LOWER AT THE TAF SITES. THE CONVECTION OF THE DAY
IS EXPECTED TO SETTLE DOWN LATER SATURDAY EVENING. OUTSIDE OF ANY
NEARBY STORM...WINDS WILL BE LIGHT AND VARIABLE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...HAL
LONG TERM...AR
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
144 AM EDT Sat Aug 10 2013
...Updated Aviation Discussion...
...Forecast Update...
Issued at 901 PM EDT Fri Aug 9 2013
Cluster of showers and storms currently across south central
Kentucky will continue to head off to the ENE through the next few
hours. Although trends with these storms have weakened, periods of
intense rainfall can still occur, especially with repeated
thunderstorms over the area. Use caution if traveling as flooding
problems will still be possible through late evening.
A pocket of drier air evident on water vapor imagery is working into
the region behind this last cluster of precipitation. Will go dry
for much of the late evening into the early morning hours, before
deeper moisture will again surge into the area and small chances for
a shower or storm will return. The concern for this dry period will
be for fog formation as skies will become mostly clear across much
of Kentucky. With the recent heavy rainfall, fog and even dense fog
will likely form. Actually already seeing some fog form on webcams.
Have include fog mention in the grids for now, but may need to
update if obs start showing dense fog development. As we move into
the pre-dawn hours, will likely see thicker cloud cover move back
over, which should improve the situation.
Issued at 533 PM EDT Fri Aug 9 2013
Updated the grids to reflect higher coverage of showers and storms
across SW portions of the CWA. Issued a Flood Advisory for areas
around Bowling Green as some training of showers and storms with
rainfall rates over 2 inches per hour at times will overspread the
area. Will need to watch for Flash Flood Warnings in the region over
the next couple of hours. Will also keep our eye on a cluster of
storms moving into the western fringes of our CWA in a couple of
hours. A few severe reports have come from the strongest storm,
however expect a weakening trend as the cluster moves in. Overall,
will mention numerous showers and storms early this evening in areas
where the biggest clusters are located, with isolated to scattered
coverage elsewhere. Please be aware that very heavy rainfall is
likely with any shower or storm and quick ponding of water on
roadways will occur.
.SHORT TERM (Now through Saturday Night)...
Issued at 305 PM EDT Fri Aug 9 2013
A line of showers and thunderstorms have begun to form along the
frontal boundary, currently draped along the Ohio River. As has been
the case this week, these are efficient rain producers, dumping a
lot of rain in a short amount of time. Traffic cameras in the
Louisville metro along with obs from SDF confirm the reduced
visibilities accompanying these cells. Thankfully, the line has been
moving relatively quickly off to the east-southeast so unless the
line really fills in, setting up a potential training effect,
flooding shouldn`t be a major concern, especially in north-central
KY where the rain has been much more hit and miss as of late. If it
is able to hold together and makes its way into the Bluegrass
region, there could be some localized problems since FFG is much
lower there due to the recent heavy rains and already saturated
soils. Unfortunately, the models aren`t handling it very well with
the exception of the latest NAM (but its performance this week has
been less than stellar) so its tough to get a solid idea of how this
will play out. While the HRRR doesn`t necessarily depict it well,
this has been one of the top performing models under this regime
and its showing scattered cells developing across much of the center
of the commonwealth. Later tonight, a mid-level wave traverses
through and the HRRR grabs onto it, bringing a cluster of showers
and embedded thunderstorms through northern KY and southern IN. This
may be a bit bullish but it would be the last hurrah for the
northern half of the forecast area as the boundary slowly sinks
south (assuming this scenario holds true).
By tomorrow, the focus for convection shifts to the south once again
along the quasi-stationary boundary. As it stands right now, any
storms that fire up during the heat of the day (despite the
continued cloud cover) should wane after sunset Saturday, allowing
for most of the area to remain dry. Under light to calm winds and
lingering low-level moisture, patchy fog could be a factor for not
only tonight (wherever it doesn`t rain) but for tomorrow night as
well. Overnight lows for both nights will range from the upper 60s
to the lower 70s from north to south, respectively. Under the
aforementioned cloud cover, highs tomorrow will again be below
normal, primarily in the mid 80s. Expect this tropical-feeling
airmass to remain in place for the entirety of this forecast period.
.LONG TERM (Sunday through Friday)...
Issued at 312 PM EDT Fri Aug 9 2013
The start of the long term period will feature generally zonal upper
flow, which will transition to an eastern trough/western ridge by
the end of the long term period. This pattern shift will allow for
drier conditions and cooler/less humid air by the middle of next
week.
A quasi-stationary frontal boundary will be draped from southwest to
northeast across southern Kentucky on Sunday. This will serve as
the focus for showers and thunderstorms to continue, mainly across
southern Kentucky as a shortwave trough rides along the boundary and
brings enhanced vertical motion. As winds turn northerly across
southern Indiana and northern Kentucky due to incoming high
pressure, think enough dry air will work in to actually keep much of
Sunday dry for those regions.
On Sunday night, the surface high will scoot east as another
shortwave trough dives through the Great Lakes region. Guidance
suggests this wave will pull the quasi-stationary front back north
which would give much more of central and northern KY decent
rainfall chances. However, am a bit skeptical of this solution as
the progged system does not appear strong enough to force the front
northward (especially if it`s continually being convectively
reinforced further south). Therefore, the more widespread activity
will likely remain across southern KY, with a general lull in
activity across northern KY and southern Indiana. Given the
continued moist atmosphere south of the front, localized flooding
will need to continue to be watched especially if areas receive
heavy rainfall through the short term period.
By Monday night into Tuesday, another surface front will approach
from the northwest. This front looks much more progressive as the
upper-level flow begins to transition to more northwesterly. As
mentioned in the previous discussion, am a bit skeptical on just how
much moisture will remain ahead of this secondary front, thus will
continue with 30-40 pops as it passes through on Tuesday. Given
the likely moist bias in guidance, instability along this front will
be less than currently progged, thus do not expect severe weather.
However, the drier air working in will help support a few healthy
downdrafts, which may lead to some sub-severe gusts in the
heavier storm cores.
The front will clear the region by Tuesday night, allowing Canadian
high pressure to build into the Ohio Valley. This will bring
welcomed relief from the muggy airmass we have seen of late, as
temperatures fall into the upper 70s/lower 80s with dewpoints in the
50s and lower 60s. This pleasant airmass will also get rid of any
additional storm potential, with dry weather expected Wednesday
through at least the end of next week.
&&
.AVIATION (06Z TAF Update)...
Issued at 140 AM EDT Sat Aug 10 2013
Surface analysis reveals a quasi-stationary boundary extending from
central Arkansas northeastward through central Kentucky and into
southern Ohio. Showers and isolated thunderstorms have redeveloped
along this boundary, with activity stretching from the Bluegrass, to
Louisville, and southwestward to Bowling Green. This activity should
be around through much of the early morning hours, with perhaps the
best coverage east and near the Ohio River toward dawn. Will carry
VCSH for all sites. Activity should diminish through the morning and
early afternoon hours, with perhaps additional development in the
afternoon. Will only try to nail down the next 12 hours as
confidence is low.
Cloud cover has build back across the sites, which is helping keep
visibilities manageable. Latest guidance continues to indicate at
least MVFR vis and cig restrictions for all sites as dawn nears. LEX
has dropped to LIFR already, but may improve near dawn as this early
morning precip nears that area. Otherwise, will hint at restrictions
in the SDF and BWG TAFs, especially with that boundary in the area.
If clouds diminish, then worse conditions could be experienced. Will
continue to monitor as clouds may be breaking up just to our west.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Update.........BJS
Short Term.....LG
Long Term......KJD
Aviation.......MJP
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
501 AM EDT SAT AUG 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM EDT SAT AUG 10 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL LOW OVER NRN
QUEBEC RESULTING IN WNW FLOW THROUGH THE NRN GREAT LAKES. THE MOST
PROMINENT UPSTREAM SHORTWAVE TROUGH WAS LOCATED OVER SW SASK. AT THE
SFC...A WEAK TROUGH EXTENDED FROM JAMES BAY INTO NE LAKE SUPERIOR
WHILE A RIDGE EXTENDED FROM ND INTO MN AND IA. IR LOOP SHOWED MAINLY
CLEAR SKIES OVER UPPER MICHIGAN WHICH HAS ALLOWED TEMPS TO DROP INTO
THE LOWER TO MID 40S INLAND. THE NRN EDGE OF A MORE EXTENSIVE AREA OF
CLOUD HAS REMAINED TO THE WEST AND SOUTH FROM NEAR ASX TO MNM.
TODAY...WITH THE WEAK 850-700 MB THERMAL TROUGH REMAINING NEAR THE
AREA...EXPECT SCT/BKN CU TO AGAIN DEVELOP THIS AFTERNOON. EVEN WITH
PROMINENT LAKE BREEZE BOUNDARIES THIS AFTERNOON IN THE RELATIVELY
LIGHT WIND FIELD...A STRONG CAP/INVERSION AROUND 700 MB...PER MDLS
SOUNDINGS AND AREA 00Z RAOBS...AND DRY LOW LEVELS WILL INHIBIT ANY
PCPN. NO MORE THAN A BRIEF SPRINKLE WOULD BE EXPECTED OUT OF THE
RELATIVELY SHALLOW CONVECTIVE CLOUDS. TEMPS WILL CLIMB TO NEAR
NORMAL...IN THE LOWER TO MID 70S.
TONIGHT...THE SASK SHRTWV WILL APPROACH UPPER MI TONIGHT BUT ANY
PCPN WITH THIS FEATURE IS EXPECTED TO REMAIN TO THE W OF THE CWA.
THE SIGNFICANT PCPN WILL REMAIN WELL TO THE SOUTH...CLOSER TO THE
850 MB FRONT OVER SRN MN. INCREASING MID CLOUDS LATE WILL KEEP TEMPS
FROM FALLING OFF AS MUCH WITH MIN READINGS IN THE MID 40S TO LOWER
50S.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 358 AM EDT SAT AUG 10 2013
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED SUNDAY
AFTERNOON AND MONDAY BEFORE BROAD HIGH PRESSURE GAINS CONTROL OF THE
REGION AND BRINGS AN EXTENDED PERIOD OF DRY WEATHER THROUGH THE
UPCOMING WEEK. TEMPERATURES WILL CONTINUE TO BE SLIGHTLY BELOW
NORMAL...WITH A COUPLE CHILLY NIGHTS EXPECTED FOR THE FIRST PART OF
THE WEEK.
SUNDAY...A BROAD MID-LEVEL TROUGH CENTERED OVER FAR NORTHERN
ONTARIO WILL BE MAKING A SOUTHWARD PUSH AT THE START OF THE PERIOD.
MAIN FORECAST FOCUS CONTINUES TO BE ON THE POTENTIAL FOR AFTERNOON
SHOWERS AND THUNDER ACROSS INTERIOR PORTIONS OF THE CWA. MODEL
GUIDANCE HAS BEEN QUITE PERSISTENT FOR SEVERAL NIGHTS NOW WITH
ADVERTISING THE PASSAGE OF A LEAD SHORTWAVE ACROSS UPPER MI ON
SUNDAY AFTERNOON AND EVENING. THIS WAVE IS A RESULT OF PHASING
BETWEEN SMALL PIECES OF ENERGY FROM WESTERN CANADA AND THE LARGER
TROUGH. THE ECMWF AND GEM ARE THE QUICKEST...AND HAVE THE TROUGH
OUTRUNNING PEAK HEATING BY CLEARING THE EASTERN CWA BY MID
AFTERNOON. THE NAM/LOCAL WRF/GFS ARE SLOWER...AND BRING THE WAVE
ACROSS THE CENTRAL CWA AROUND EARLY AFTERNOON. SUBTLE NW FLOW
FEATURES CAN BE QUITE FICKLE THIS TIME OF YEAR...SO AM NOT TOO
CONFIDENT IN JUMPING ON EITHER SOLUTION ATTM. GIVEN COMPETING
DYNAMICS BETWEEN THE MID-LEVEL WAVE AND THE LEFT ENTRANCE OF AN 80
KT UPPER JET...WILL MAINTAIN THE FOCUS FOR PRECIP CHANCES ACROSS THE
SOUTH CENTRAL AND INTERIOR EAST WHERE ASSISTANCE FROM LAKE BREEZE
CONVERGENCE WILL BOOST DIURNAL ACTIVITY.
ONE CONCERN WITH THUNDER POTENTIAL OVER THE PAST COUPLES DAYS HAS
BEEN LOWER INSTABILITY DUE TO CLOUDS FROM CONVECTION TO THE SOUTH.
WITH MLCAPE PEAKING AT ONLY 500 J/KG FAR SOUTH CENTRAL...THUNDER
COVERAGE WILL BE LIMITED. A DRY SUBCLOUD LAYER COULD STILL RESULT IN
SOME GUSTY WINDS TO 35 MPH WITH ANY SHOWERS THOUGH AS DOWNDRAFT CAPE
WILL BE OVER 500 J/KG.
SUNDAY NIGHT AND MONDAY...ANY ACTIVITY SUNDAY AFTERNOON SHOULD
DIMINISH WITH THE PASSAGE OF THE WAVE AND LOSS OF DAYTIME HEATING. A
WEAK SFC TROUGH ASSOCIATED WITH THE MID-LEVEL TROUGH WILL STILL BE
DRIFTING ACROSS THE EASTERN CWA INTO THE OVERNIGHT HOURS...BUT DO
NOT EXPECT ANY LINGERING SHOWERS GIVEN WEAK LIFT AND DRIER AIR. THE
MAIN TROUGH IS THEN PROGGED TO CROSS THE CWA DURING THE DAY ON
MONDAY. MID-LEVEL Q-VECTOR CONVERGENCE WITH A DECENT UPPER-LEVEL
NEGATIVE PV ANOMALY WILL BRING MODEST LIFT ACROSS THE NORTHERN CWA
AND LAKE SUPERIOR MONDAY AFTERNOON. ONCE AGAIN...DAYTIME HEATING
WILL ASSIST WITH PRECIP COVERAGE IN THE AFTERNOON. DO NOT EXPECT ANY
MORE COVERAGE THAN SUNDAY AFTERNOON AS MID-LEVEL CAPPING BEHIND
SUNDAYS TROUGH WILL LIMIT VERTICAL GROWTH OF ANY SHOWERS. WILL
MAINTAIN GOING FORECAST WITH BEST CHANCE POPS AND SLIGHT CHANCE OF
THUNDER SOUTH-CENTRAL AND INTERIOR EAST IN THE AFTERNOON.
TUESDAY THROUGH FRIDAY...HIGH PRESSURE WILL BUILD INTO THE CWA FROM
THE WEST BEGINNING MONDAY NIGHT AND SETTLE OVER THE REGION TUESDAY
NIGHT. PWAT VALUES OF 0.5 INCHES OR LESS AND LIGHT WINDS WILL LEAD
TO GREAT RADIATIONAL COOLING BOTH MONDAY AND TUESDAY NIGHTS.
GUIDANCE THAT HAS VERIFIED THE BEST OVER RECENT COOL NIGHTS PRODUCES
MIN TEMPS WELL INTO THE 40S INLAND...ESPECIALLY TUESDAY NIGHT. COULD
EVEN SEE SOME UPPER 30S TUESDAY NIGHT AT THE TYPICAL COOL
SPOTS...BUT DID NOT GO THAT LOW QUITE YET GIVEN UNCERTAINTY IN THE
EXACT PLACEMENT OF THE SFC HIGH. OVERALL...LOWERED TEMPS BY A COUPLE
DEGREES FOR BOTH NIGHTS. ALSO ADDED SOME PATCHY FOG ACROSS THE
INTERIOR WEST HALF MONDAY NIGHT SINCE THEY WILL HAVE SEEN A FEW
SHOWERS ON MONDAY AFTERNOON AND CROSSOVER TEMPS SHOULD BE SURPASSED
BY SEVERAL DEGREES.
ANOTHER WEAK TROUGH AXIS FROM THE MAIN EASTERN CANADIAN TROUGH WILL
SKIRT NE LAKE SUPERIOR THURSDAY. WITH MOISTURE LACKING AND BEST
DYNAMICS WELL NORTHEAST...KEPT PRECIP OUT OF THE FORECAST. A
PACIFIC-BASED WAVE COULD BEGIN AFFECTING THE WEST BY LATE
FRIDAY...BUT MODEL CONSISTENCY HAS BEEN POOR SO CONFIDENCE IS LOW IN
ANY PRECIP LATE IN THE WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 131 AM EDT SAT AUG 10 2013
VFR CONDITIONS ARE EXPECTED AT ALL THREE TAF SITES THIS FORECAST
PERIOD. KSAW WILL SEE A NE LAKE BREEZE SAT AFTERNOON.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 500 AM EDT SAT AUG 10 2013
HIGH PRESSURE MOVING INTO THE WRN GREAT LAKES WILL BRING RELATIVELY
LIGHT WINDS BELOW 20 KNOTS THROUGH THE WEEKEND. A WEAK TROUGH WILL
CROSS THE GREAT LAKES MONDAY...BUT AGAIN...WINDS WILL REMAIN LESS
THAN 20 KNOTS. HIGH PRESSURE WILL RESUME CONTROL OF THE WRN GREAT
LAKES TUESDAY THROUGH THE END OF THE WEEK TO KEEP WINDS GENERALLY
LIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KLUBER
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
318 AM CDT Sat Aug 10 2013
.SHORT TERM: (Through Late This Afternoon)
Issued at 317 AM CDT Sat Aug 10 2013
Early morning precipitation over eastern OK and southern MO was
being handled fairly well by the RAP. Based on RAP forecasts of H85
moisture convergence, SHRA/TSRA over southern MO/IL should begin to
taper off after 15Z. Heavy downpours are still possible this morning
since PW values remain near 2 inches. With a surface high pressure
center building into the region and a drier air mass spreading
southward today, any afternoon convection should be confined to
areas closer to the active quasistationary front near the MO/AR
border.
Kanofsky
.LONG TERM: (Tonight through Friday)
Issued at 317 AM CDT Sat Aug 10 2013
All of the 00z NWP output is much more aggressive with the southward
surge of the surface ridge into the mid Mississippi Valley tonight
and into Sunday. Not only will this mean lower dewpoints and
slightly cooler temps, but this will also give the stubborn
baroclinic zone that has been anchored over southern Missouri and
northern Arkansas a gentle but significant southward nudge. This
will greatly lessenthe threat of convection that has seeminly
been a nightly occurrance for almost a week over southern Missouri.
I have held onto some low pops in our southern counties both tonight
and Sunday just in case the later solutions back off on the
southward push of the ridge, but if 00z guidance verifies with its
trends any rainfall tonight and Sunday should primarily fall south
of our CWA.
Surface ridge still expected to retreat Sunday night into Monday,
allowing the resultant return flow to cause a northward return of
the warm and moist air. Have continued slight chance pops for most
areas on Sunday night, but it would appear better threat for
convection will hold off until Monday when shortwave energy will be
able to interact with a diurnal increase of instability. This
threat should continue into Monday night. These thunderstorm
chances should shut down with the arrival of the next front...which
the 00z guidance suggests will be about 12 hours slower that earlier
solutions. POPS should diminish from north to south Monday night and
Tuesday.
Consensus of tonight`s medium range guidance dovetails with that of
yesterday`s day shift, and indicates a fairly significant deepening
of the upper trof that is progged to form over the Great Lakes and
eastern U.S during the latter half of next week. This in turn means
stronger high pressure and a bit more of the associated Canadian
airmass backdooring into region. Going trends for the
Wednesday-Friday frame still look very good, with this early surge
of Canadian air providing the region with unseasonably low
humidities and cooler than average temperatures for mid August, and
little if any threat of rain.
Truett
&&
.AVIATION: (For the 06z TAFs through 06z Saturday Night)
Issued at 1050 PM CDT Fri Aug 9 2013
The focus for most of the convection late tonight and Saturday
should continue to be south of the taf sites. Much of the low-mid
level cloudiness may advect east-southeast of COU and UIN late
tonight and east-southeast of the St Louis metro area Saturday
morning. Patchy fog will develop late tonight/early Saturday
morning due to the light sfc winds...and especially in areas where
the clouds clear out. N-nely sfc wind will increase to around 7-8
kts by late Saturday morning and afternoon...then become light
again Saturday evening.
Specifics for KSTL: VFR low-mid level clouds will continue late
tonight...then advect east-southeast of STL Saturday morning. The
light sfc wind will increase to around 8 kts Saturday afternoon
from a nly direction...then diminish again Saturday night.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1111 PM CDT Fri Aug 9 2013
.UPDATE:
Issued at 935 PM CDT Fri Aug 9 2013
The highly unusual August pattern continues.
A weak cold front has since pushed further into central IL and
about halfway between KUIN and KSTL in MO. As a result, the old
line of SHRA/TSRA has dissipated, but it has helped to give more
form to the sprinkles that have been moving through the area, and
has resulted in isolated SHRA in parts of SW IL. This feature is
essentially going to merge with the upper level disturbance now
moving through east- central MO, where the SHRA there has all but
faded after sunset. Look for a continued low threat for SHRA into
the overnight between this upper level disturbance moving through
and the weak cold front that will primarily be focused on the IL
side of the MS river.
If clouds exit faster than anticipated, the low temp-dewpoint
spreads may result in another night of patchy fog. Current
indications are they will linger for much of the night, though.
Just south of the forecast area, an old frontal boundary exists
and has been the main focus for waves of rain for the past several
nights on the cool side. The next 24 hours will probably not be
much different, with another wave of SHRA/TSRA expected to move
into SE MO Saturday morning, the difference expected to be the
trend for rain further and further south with each day.
Temps look to be in the ballpark for mins in the 60s.
TES
&&
.SHORT TERM: (Through Late Tonight)
Issued at 317 PM CDT Fri Aug 9 2013
Area of rain extending from central Missouri into southwest Illinois
has persisted on the north side of a side of MCV that is currently
tracking through southeast Missouri. This rain will continue to
show a slow decrease in areal coverage and intensity as the vort
moves off to the east. Focus for additional showers and
thunderstorms this evening will then shift closer to a front over
southern Missouri into southern Illinois. RAP and Local WRF shows
low level forcing persisting along and north of this front most of
the night, so will keep chances of showers and thunderstorms mainly
in areas along and south of I-44 in Missouri and I-64 in
Illinois.
Britt
.LONG TERM: (Saturday through Next Friday)
Issued at 317 PM CDT Fri Aug 9 2013
Primary concern for Saturday through early next week continues to be
timing and intensity of precipitation as quasi-zonal/northwest flow
pattern continues to control our weather. Am continuing the
persistence forecast with high chance/likely pops across the eastern
Ozarks and extreme southwest Illinois, fading to low chance/slight
chance up along the I-70 corridor for Saturday. This morning`s
850mb analysis showed a strong dewpoint gradient along the I-70 with
northerly flow across northern Missouri and moist west-southwest
flow to the south of the gradient. This gradient along with the
northerly flow feeding it is probably at least partially responsible
for the lack of northward progress for today`s precipitation. All
short range guidance keeps the 850mb dewpoint gradient in basically
the same place, hence the persistence forecast. The gradient washes
out on Sunday allowing deeper moisture to filter back into the
region. However, there appears to be a general lack of dynamic
forcing on Sunday with just some weak isentropic lift on 10kt low
level southwest flow. With nothing obvious to focus convection,
will spread chance pops further north, but am not particularly
excited about going with pops higher than chance anywhere at this
time. On Monday, a strong shortwave is forecast to drop down into
the Great Lakes region which should amplify the eastern trof and
push a cold front into the mid Mississippi Valley with a
corresponding increase in pops across the area.
Medium range guidance shows a sprawling high pressure system
building down across the Upper Midwest into the Great Lakes region
late Tuesday into Wednesday. This airmass will be cooler and much
drier than is normal for mid August. 850mb temps on the GFS are
progged to be around 10-12C...which would mix down to the low to mid
70s. The ECMWF is somewhat warmer at 12-14C. Given the
discrepancy...have opted to to stick with ensemble guidance with
highs in the upper 70s to low 80s and lows in the upper 50s to low
to 60s.
Carney
&&
.AVIATION: (For the 06z TAFs through 06z Saturday Night)
Issued at 1050 PM CDT Fri Aug 9 2013
The focus for most of the convection late tonight and Saturday
should continue to be south of the taf sites. Much of the low-mid
level cloudiness may advect east-southeast of COU and UIN late
tonight and east-southeast of the St Louis metro area Saturday
morning. Patchy fog will develop late tonight/early Saturday
morning due to the light sfc winds...and especially in areas where
the clouds clear out. N-nely sfc wind will increase to around 7-8
kts by late Saturday morning and afternoon...then become light
again Saturday evening.
Specifics for KSTL: VFR low-mid level clouds will continue late
tonight...then advect east-southeast of STL Saturday morning. The
light sfc wind will increase to around 8 kts Saturday afternoon
from a nly direction...then diminish again Saturday night.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BILLINGS MT
327 AM MDT SAT AUG 10 2013
.SHORT TERM...VALID FOR TDY AND SUN...
A WARMING TREND WILL BEGIN TODAY AND CONTINUE INTO SUN WITH HEIGHT
RISES ALOFT...BUT LOW-LEVEL EASTERLY FLOW WILL KEEP SOME CHANCE OF
STORMS IN THE FORECAST...ESPECIALLY IN SOUTHEASTERN MT.
TODAY...WE WILL KEEP A MENTION OF PATCHY FOG IN THE FORECAST UNTIL
15 UTC FOR MOST OF THE AREA WITH SURFACE DEWPOINT DEPRESSIONS LESS
THAN 10 F OVER PARTS OF THE AREA AS OF 09 UTC. HOWEVER...NOT A LOT
OF SUPPORT EXISTS FOR ITS FORMATION IN GUIDANCE...INCLUDING RECENT
RUNS OF THE HRRR...WHICH OFTEN PICKS UP ON THIS SITUATION. WE ALSO
KEPT LOW POPS IN SOUTHEASTERN MT THROUGH 15 UTC TO ACCOUNT FOR THE
SLOW EXIT OF A WEAK SHORT WAVE IN THAT REGION. THE BIG PICTURE FOR
TODAY WILL FEATURE MODEST HEIGHT RISES ALOFT...AND A WARMING TREND
AT THE SURFACE. WE HAVE SLIGHT CHANCE POPS IN THE FORECAST FOR THE
AFTERNOON EVERYWHERE...BUT THAT WAS ACTUALLY A REDUCTION IN VALUES
FOR SOUTHEASTERN MT BECAUSE IT LOOKS LIKE FORCING FOR STORMS COULD
HOLD OFF UNTIL 00 UTC OR LATER IN THAT AREA. THE EASTERLY FLOW AND
MLCAPE TO 500 J/KG IN SOUTH CENTRAL MT MAY YIELD CONVECTION ACROSS
THE HIGHER TERRAIN THIS AFTERNOON TOO...WITH A TENDENCY FOR ANY OF
THAT ACTIVITY TO MOVE EASTWARD INTO THE LOWER ELEVATIONS SINCE THE
BOUNDARY LAYER SHOULD NOT BE TOO CAPPED. WE CHOSE TO LEAVE POPS IN
THE 20 PERCENT RANGE EVEN IN SOUTH CENTRAL MT THOUGH DESPITE QUITE
A BIT OF SUPPORT FOR STORMS IN HIGH-RESOLUTION GUIDANCE BECAUSE IT
IS POSSIBLE THAT THE SYNOPTIC-SCALE ENVIRONMENT /RISING HEIGHTS AT
500 HPA/ WILL INHIBIT MORE THAN ISOLATED DEVELOPMENT.
TONIGHT...CONFIDENCE IS INCREASING IN THUNDERSTORMS OVER SOUTHEAST
MT DURING THE EVENING AS THE CONVECTIVELY-ACTIVE SHORT WAVE TROUGH
OBSERVED OVER NORTHERN ID ON 09 UTC MOISTURE CHANNEL IMAGES SHEARS
SOUTHEAST INTO THE NORTHERN HIGH PLAINS. SEVERAL MEMBERS OF THE 00
UTC SPC SSEO KEY ON SOUTHEASTERN MT FOR CONVECTION IN THE 00 TO 06
UTC TIME FRAME...AND RECENT RAP RUNS ALSO SIMULATE CONVECTION OVER
THAT AREA /ALBEIT A BIT EARLIER/. FORECAST SOUNDINGS CALL FOR 1000
TO 1500 J/KG OF MLCAPE AND 0-6-KM BULK SHEAR NEAR 40 KT...WHICH IS
SUFFICIENT FOR ORGANIZED SEVERE STORMS. WE CHOSE TO INCLUDE A RISK
OF SEVERE STORMS IN THE FORECAST...BUT WE HAVE TO ADMIT IT REMAINS
VERY CONDITIONAL ON STORMS ACTUALLY FORMING. OTHERWISE...IF STORMS
DEVELOP OVER THE HIGHER TERRAIN IN SOUTH CENTRAL MT THIS AFTERNOON
THEN THEY WILL LIKELY CONTINUE SPREADING EAST THIS EVENING...WHICH
WILL BE THE HIGHEST PROBABILITY FOR BILLINGS TO SEE IMPACTS FROM A
STORM. DEEP-LAYER SHEAR IS WEAKER IN SOUTH CENTRAL MT...BUT WITH A
WELL-MIXED BOUNDARY LAYER...STRONG AND GUSTY WINDS ARE POSSIBLE IF
STORMS DO AFFECT THE AREA.
SUN...A MUCH DRIER AND MORE DEEPLY MIXED AIR MASS WILL SPREAD INTO
SOUTH CENTRAL MT...WITH FORECAST SOUNDINGS SUGGESTING MIXING COULD
LOWER DEWPOINTS INTO THE 20S F IN PLACES LIKE LIVINGSTON. EASTERLY
FLOW WILL MAINTAIN DEEPER MOISTURE OVER SOUTHEASTERN MT...WITH LOW
AND CONDITIONAL POPS FOR STORMS THUS WARRANTED IN THAT AREA. HIGHS
WILL TAKE ANOTHER MOVE UPWARD WITH MORE WARMING ALOFT. SCHULTZ
.LONG TERM...VALID FOR MON...TUE...WED...THU...FRI...
ONLY SMALL ADJUSTMENTS WERE MADE TO THE EXTENDED PERIOD FORECASTS
FOR THIS MORNINGS PACKAGE. CONFIDENCE IS HIGH IN AN AMPLIFIED
RIDGE OVER THE REGION WITH PRECIPITABLE WATER HIGHEST IN THE EAST
AND LOWEST IN THE WEST. THEREFORE...THE CHANCE OF MEASURABLE
PRECIPITATION WILL BE HIGHER IN THE EASTERN ZONES. WE CONTINUE TO
SEE PERIODS OF NOCTURNAL STORMS POSSIBLE IN THE CENTRAL AND EAST
DUE TO LOW LEVEL JET FORMATION. HIGH PRESSURE ALOFT DOES BREAK
DOWN AT MIDWEEK AS A SHORT WAVE ROUNDS THE RIDGE AND INTERACTS
WITH THE MOISTURE OVER THE EAST FOR A BETTER CHANCE OF
THUNDERSTORMS. THE RIDGE THEN STRENGTHENS LEADING TO ABOVE NORMAL
TEMPERATURES. I BEGAN TRENDING AFTERNOON HIGHS UP FOR THE LATTER
PART OF NEXT WEEK BASED ON THESE TRENDS. BT
&&
.AVIATION...
VFR CONDITIONS WILL GENERALLY PREVAIL OVER THE FORECAST TERMINALS
THROUGH 18Z. SHOWERS AND THUNDERSTORMS CAN BE EXPECTED TO DEVELOP
IN THE AFTERNOON HOURS WITH LOCALLY REDUCED VISIBILITY AND
CEILINGS IN THUNDERSTORMS. THUNDERSTORMS ACTIVITY IS EXPECTED TO
DIMINISH BY 03Z. BT
&&
.PRELIMINARY POINT TEMP/POPS...
TDY SUN MON TUE WED THU FRI
-------------------------------------------------------
BIL 086 059/089 060/089 060/087 060/087 059/091 059/092
2/T 31/U 12/T 22/T 22/T 21/U 10/U
LVM 088 051/090 051/088 051/088 052/087 052/089 051/090
2/T 21/U 12/T 22/T 22/T 21/U 11/U
HDN 088 057/092 059/091 060/089 059/089 058/092 059/095
2/T 32/T 12/T 32/T 22/T 21/U 11/U
MLS 085 060/087 063/089 063/088 061/088 060/091 062/094
2/T 42/T 22/T 22/T 23/T 31/U 11/U
4BQ 085 055/088 059/089 061/088 058/087 057/090 059/093
2/T 42/T 22/T 33/T 33/T 31/U 11/U
BHK 079 056/082 058/084 059/083 057/083 057/087 058/089
2/T 42/T 22/T 22/T 23/T 32/T 11/U
SHR 086 054/089 054/088 057/087 055/087 055/088 055/091
2/T 32/T 22/T 23/T 33/T 31/U 11/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
1055 PM MDT Fri Aug 9 2013
Aviation Section Updated.
.UPDATE...
Scattered afternoon thunderstorms dissipated with sunset. However,
an upper level shortwave feature lifting northward through western
Montana is associated with a line of thunderstorms from Missoula to
Helena and Bozeman. Evening HRRR guidance splits a portion of the
shortwave to the east and brings precipitation through N. central MT
through 12Z Saturday morning. Satellite and radar trends show this
split as thunderstorms in NW Montana are drifting NW while those in
the Helena area are drifting NE. RUC and NAM guidance do not support
this nocturnal activity as thunderstorms encounter the relatively
cooler and more stable air mass in place over N. central MT. Raised
POPs along the Rocky Mountain front for tonight to reflect these
trends. Nutter
&&
.AVIATION...
UPDATED 0455Z.
Late evening thunderstorm activity has spread a mid-level overcast
across north-central MT, with a line of rain showers over the
mountains southwest of KGTF. VFR conditions prevail except for
possible MFVR near these rain showers. Remaining cloud cover will
break after dawn, allowing the airmass to destabilize with another
round of scattered afternoon thunderstorms. Gusty surface winds
should be expected near thunderstorms but otherwise, winds will
remain light.
&&
.PREV DISCUSSION...
/ISSUED 550 PM MDT Fri Aug 9 2013/
Tonight through Sunday...Monsoonal moisture continues to be drawn
up and across southern Montana this afternoon resulting in the
development of scattered thunderstorms. Moisture is present as
well as decent CAPE values but the shear environment is marginal
at best. As a result, the storms are fairly slow moving and
generally low-topped. With precipitable water values continuing
around an inch or so, heavy rains are possible with these
thunderstorms. Convective activity should gradually end by
midnight with clearing skies. Saturday looks to be a similar day
to today as monsoonal moisture will continue to move north.
Thunderstorms will develop again Saturday afternoon and will be a
bit more widespread in areal coverage. Isolated to scattered
thunderstorms will continue Sunday afternoon and evening as
conditions will change little through the weekend. Temperatures
will warm over the weekend with readings slightly above seasonal
averages. Emanuel
Sunday night through Friday...Early in the week an upper ridge is
forecast to be over the Rockies with southwest to west flow aloft
over the forecast area. Expect a few weather disturbances to be
embedded in the flow aloft but the models are not in good agreement
with their details so will employ a broadbrush approach to the
forecast. There is some evidence from the models that southwest
Montana could have a drier airmass in comparison to locations
farther north so during the afternoon and evening will generally go
with isolated thunderstorms over southwest Montana and scattered
thunderstorms over northwest Montana. Also will play the diurnal
card and have lower chances of precipitation during the late night
and morning relative to during the afternoon and evening. Thursday
the latest GEM (Canadian) and ECMWF (European) model runs redevelop
the upper ridge west of the forecast area and then move it over the
forecast area by early Friday. The GFS (U.S.) model run does not
forecast this redevelopment and continues a southwest flow aloft.
However other forecast guidance from the GFS does show some support
for the ECMWF solution for Friday. Will go with slightly lower
chances of precipitation later in the week relative to early in the
week due to the possibility of an upper ridge over the forecast area
later in the week. Expect little day-to-day change in high
temperatures with highs in the 80s.
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 54 86 55 88 / 20 30 20 20
CTB 51 82 52 83 / 20 20 20 50
HLN 56 88 57 89 / 30 30 20 20
BZN 49 88 49 88 / 30 30 20 20
WEY 37 79 37 78 / 20 20 10 10
DLN 48 85 49 85 / 20 30 20 20
HVR 53 83 55 85 / 10 20 20 20
LWT 52 81 54 83 / 30 30 30 20
&&
$$
weather.gov/greatfalls
AREA FORECAST DISCUSSION
NWS HASTINGS NE
244 AM CDT SAT AUG 10 2013
.UPDATE...
ISSUED AT 242 AM CDT SAT AUG 10 2013
UPDATED THE FORECAST OVERNIGHT TO INCLUDE SOME SMALL CHANCES OF
SHOWERS IN THE FAR NORTHERN CWA...BUT THESE DO NOT APPEAR TO BE
LASTING LONG AND SHOWING SIGNS OF WANING.
UPDATE ISSUED AT 941 PM CDT FRI AUG 9 2013
TRIMMED BACK POPS FOR THE TONIGHT PERIOD...MAINLY TO AREAS
CONFINED TO OUR NORTHWESTERN COUNTIES. THESE SHOWERS SHOULD N0T
LAST PAST MIDNIGHT AS MESOSCALE ANALYSIS INDICATES AN INCREASE IN
CAPPING ACROSS AREAS WHERE CURRENT THUNDERSTORM ACTIVITY IS
ONGOING. ALSO TRIMMED BACK THE PATCHY FOG TO ACCOUNT FOR INCREASE
CLOUD COVER ACROSS OUR NORTH...WHICH SHOULD INHIBIT FOG IN THESE
AREAS. THE PATCHY FOG STILL INCLUDES THE TRI-CITIES AND AREAS
SOUTH OF I-80...WITH A TIME FRAME FROM ROUGHLY 08Z TO 13Z THIS
MORNING.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 345 PM CDT FRI AUG 9 2013
THE PRIMARY ISSUES DURING THE NEXT 24 HOURS INVOLVES ISOLATED AND
LIKELY NON-SEVERE SHOWER/STORM DEVELOPMENT INTO THIS
EVENING...AND WHETHER OR NOT ANY IMPACTFUL FOG MIGHT DEVELOP AGAIN
OVERNIGHT. HAVE MAINTAINED A SHOWER/STORM-FREE FORECAST CWA-WIDE
FROM LATE THIS EVENING THROUGH SATURDAY AFTERNOON.
20Z OBJECTIVE SURFACE ANALYSIS REVEALS A VERY SUBTLE...WEAK COLD
FRONT ALIGNED GENERALLY EAST-WEST ACROSS THE HEART OF THE NEB
CWA...ALTHOUGH ONE HAS TO LOOK PRETTY TO FIND IT...AS ALL IT
REALLY DOES IS SEPARATE A LIGHT EAST-NORTHEAST BREEZE FROM A LIGHT
EAST TO EAST-SOUTHEAST ONE. THIS LIGHT FLOW WITH SUSTAINED BREEZES
MOST ALL AREAS NO MORE THAN 5-10 MPH IS A RESULT OF BROAD SURFACE
HIGH PRESSURE OVER THE REGION...WITH THE CORE OF THE PARENT HIGH
AROUND 1027 MILLIBARS CENTERED WELL TO THE NORTH OVER
SASKATCHEWAN. ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL
DATA REVEALS RATHER WEAK FLOW ALOFT OVER THE CWA...GENERALLY
WESTERLY UP AT 300MB...NORTHERLY AT 500 MB...AND EVEN FARTHER DOWN
FROM THE EAST-NORTHEAST AT 700MB. ON THE LARGE SCALE...THE CENTRAL
PLAINS LIES IN THE INTERFACE BETWEEN A BROAD TROUGH AND EMBEDDED
VIGOROUS SHORTWAVE TRACKING EAST ACROSS SOUTHEAST CANADA...AND A
RIDGE AXIS EXTENDING EAST-WEST ACROSS THE SOUTHERN CONUS AND THEN
NORTHWARD INTO THE ROCKIES. ON A MORE REGIONAL LEVEL...A LOW-
AMPLITUDE MID LEVEL DISTURBANCE IS LIFTING OUT ACROSS EASTERN
KS/WESTERN MO. OTHER VERY SUBTLE DISTURBANCES APPEAR TO BE
RIPPLING OUT OF THE WY AREA TOWARD WESTERN NEB/SOUTHWEST SD...AND
HELPING TO KICK OFF STORMS IN THE NORTHERN PANHANDLE.
LOCALLY...JUST WITHIN THE PAST HOUR A FEW SMALL...ISOLATED
SHOWERS/POSSIBLY WEAK STORMS HAVE BUBBLED UP OVER DAWSON/BUFFALO
COUNTIES BUT HAVE SHOWED LITTLE SIGN OF MAINTAINING ORGANIZATION.
VISIBLE SATELLITE REVEALS PARTLY TO MOSTLY CLOUDY SKIES OVER THE
CWA AT MID-AFTERNOON...WITH A DECENT LOW LEVEL CUMULUS FIELD
ACROSS MUCH OF THE CENTRAL/WEST...AND SOME LINGERING HIGH CIRRUS
STILL GRADUALLY DEPARTING EASTERN COUNTIES. HIGH TEMPS APPEAR TO
BE FAIRLY WELL ON TRACK...WITH MOST AREAS LIKELY TO END UP IN THE
81-84 RANGE.
GOING FORWARD THROUGH THE LATE AFTERNOON HOURS THROUGH
03Z/10PM...HAVE OPTED TO KEEP THINGS SIMPLE AND ADVERTISE A SLIGHT
CHANCE OF SHOWERS/ISOLATED THUNDERSTORMS CWA-WIDE...ALTHOUGH WOULD
ANTICIPATE THE MOST LIKELY LOCALIZED DEVELOPMENT TO CONTINUE
TARGETING THE WESTERN HALF OF THE NEB CWA...WHERE LATEST MESO-
ANALYSIS INDICATES 0-1KM MLCAPE UP TO AROUND 1500 J/KG...AND WITH
LITTLE IF ANY CINH BUT ALSO VERY LIMITED FORCING FOR ASCENT. WITH
DEEP-LAYER SHEAR AVERAGING NO MORE THAN 15-20KT AND MID LEVEL
LAPSE RATES RATHER SHALLOW AT ONLY 5-6 C/KM...THE THREAT FOR
STRONG TO SEVERE STORMS APPEARS TO BE QUITE LIMITED IF NOT NON-
EXISTENT. POST-03Z/10PM...WILL AIM FOR A DRY REST OF THE
NIGHT...AS ANY DIURNAL SUPPORT FOR CONVECTION FROM AFTERNOON
HEATING WILL BE ON THE WANE...AND GIVEN THAT THE MAIN TRACK OF LOW
AMPLITUDE MID LEVEL DISTURBANCES OVERNIGHT SHOULD GENERALLY TARGET
THE NEB/SD BORDER AREA. FURTHERMORE...THE NOSE OF A MODEST 35KT
850MB LOW LEVEL JET CLEARLY AIMS INTO SOUTHERN SD/FAR NORTH CENTRAL
NEB OVERNIGHT...WHICH IS WHERE MOST MODELS INCLUDING THE NAM AND
4M WRF-NMM FOCUS CONVECTION. THAT BEING SAID...WILL HAVE TO KEEP
AN EYE ON THE NORTHWEST CWA AS THE LATEST HRRR MAINTAINS SOME
SANDHILLS CONVECTION WITHIN 50 MILES OF THE CWA THROUGH AROUND
MIDNIGHT...BUT FEEL THIS MAY BE A BIT CLOSER TO HOME THAN IT
ACTUALLY WILL BE. AT THE SURFACE TONIGHT...BREEZES WILL REMAIN
QUITE LIGHT AND AVERAGE UNDER 5 MPH...WHILE GRADUALLY TURNING TO A
SOUTHERLY DIRECTION. GIVEN THE LIGHT WIND SETUP...THERE IS AT
LEAST SOME CONCERN THAT FOG COULD AGAIN DEVELOP AND REDUCE
VISIBILITY TO 1 MILE OR LESS. HOWEVER...THE CONSENSUS OF
MODELS/GUIDANCE IS THAT TONIGHT/S FOG EVENT SHOULDN/T BE AS
DENSE/IMPACTFUL...POSSIBLY DUE TO SLIGHTLY BETTER BETTER MIXING
JUST ABOVE THE SURFACE. FOR NOW...WILL MAINTAIN THE GENERIC PATCHY
FOG MENTION CWA-WIDE FOR THE LATE NIGHT/EARLY MORNING HOURS
INTRODUCED BY THE PREVIOUS SHIFT...BUT WILL DEFER TO THE NEXT FEW
SHIFTS TO POTENTIALLY RAMP UP THIS FOG WORDING IF NEED BE. AS FOR
LOW TEMPS...ACTUALLY NUDGED DOWN 1-2 DEGREES FROM PREVIOUS IN MOST
SPOTS PER A GUIDANCE BLEND...WHICH PUTS MOST AREAS DOWN BETWEEN
57-61 DEGREES.
TURNING TO THE SATURDAY DAYTIME PERIOD 12Z-00Z/7AM-7PM...MAINTAINED
A RAIN-FREE FORECAST CWA-WIDE. IN THE MID/UPPER LEVELS...FAIRLY
WEAK TO MODEST WEST-NORTHWEST FLOW WILL MAINTAIN OVER THE CENTRAL
PLAINS AT/ABOVE 500MB...AND THERE SHOULD BE SOME SUBTLE HEIGHT
RISES AS WELL...AS THE SOUTHERN PLAINS/SOUTHERN ROCKIES RIDGE
EDGES NORTH JUST A BIT. THE PRIMARY MID LEVEL SHORTWAVE TROUGH
TRACK DURING THE DAY WILL BE FROM SD TOWARD SOUTHWEST MN/NORTHWEST
IA...AND THIS DISTURBANCE SHOULD TEAM WITH AN EAST-WEST QUASI-
STATIONARY FRONT SETTING UP NEAR THE NEB/SD BORDER TO FOCUS THE
VAST MAJORITY OF DAYTIME CONVECTION AT LEAST 50-100 MILES NORTH
AND POSSIBLY NORTHWEST OF THE CWA. THE ODDS OF CONVECTION FORMING
LOCALLY WITH DAYTIME HEATING SEEMS SMALLER THAN TODAY GIVEN
SLIGHTLY WARMER TEMPS EVIDENT AT 700MB...DESPITE MODEST MLCAPE
VALUES CLIMBING INTO THE 500-1000 J/KG RANGE PER THE 18Z NAM.
MODEL FORECASTS SOUNDINGS ALSO CLEARLY SHOW A WEAK BUT EVIDENT CAP.
OTHERWISE...ALTHOUGH BY NO MEANS WINDY...THE LATE MORNING-
AFTERNOON HOURS SHOULD FEATURE SOME OF THE MOST NOTICEABLE MODEST
BREEZES FELT IN MOST OF THE CWA IN SEVERAL DAYS...AS A TIGHTENED
PRESSURE GRADIENT TO THE EAST OF HIGH PLAINS LEE TROUGH SHOULD
PROMOTE SUSTAINED SOUTHERLY SPEEDS 10-15 MPH MOST AREAS. GIVEN THE
SOUTHERLY BREEZES...SLIGHTLY WARMER TEMPS AT 850MB...AND LIKELY NO
WORSE THAN PARTLY CLOUDY SKIES...SEE LITTLE REASON WHY HIGH TEMPS
SHOULDN/T BE AT LEAST A TOUCH HIGHER THAN TODAY. AS A
RESULT...NUDGED UP PREVIOUS HIGHS 1-2 DEGREES IN MOST AREAS...WITH
MOST OF THE CWA AIMED FOR FAIRLY UNIFORM HIGHS BETWEEN 83-86
DEGREES.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 344 PM CDT FRI AUG 9 2013
GUIDANCE SUGGESTS QUASI-ZONAL TO NORTHWESTERLY MID TO UPPER LEVEL
FLOW WILL PERSIST OVER THE CENTRAL PLAINS THROUGH MUCH OF THE LONG
TERM FORECAST PERIOD...WITH THE POSSIBILITY OF MULTIPLE MID LEVEL
PERTURBATIONS MOVING OVER THE AREA. PRECIPITATION CHANCES REMAIN
INTACT THROUGHOUT THE LONG TERM FORECAST PERIOD AS A RESULT.
STARTING SATURDAY NIGHT...THERE ARE SIGNS...PRIMARILY FROM THE
EC...OPERATIONAL GFS AND SREF-MEAN...THAT CENTRAL TO NORTHERN HIGH
PLAINS CONVECTION FROM SATURDAY AFTERNOON/EVENING MAY HOLD TOGETHER
LONG ENOUGH...PRIMARILY DUE TO LOW LEVEL THERMAL ADVECTION ALONG THE
AXIS OF A ~30KT 850MB JET STREAK...TO IMPACT NORTHERN PORTIONS OF
OUR CWA. CONFIDENCE IS NOT OVERLY HIGH THAT MEASURABLE PRECIPITATION
WILL BE REALIZED ACROSS OUR AREA SATURDAY NIGHT AND AS A
RESULT...POPS ONLY IN THE 20-30% RANGE CURRENTLY EXIST. HEADING INTO
THE DAY SUNDAY...LOW LEVEL CONVERGENCE ALONG A LOW LEVEL BAROCLINIC
ZONE/TROUGH COULD PROMOTE ENOUGH LIFT...ALONG WITH A PASSING MID
LEVEL PERTURBATION...TO PROMOTE PRECIPITATION PRODUCTION ACROSS
PORTIONS OF THE REGION. WHERE EXACTLY THE BOUNDARY POSITIONS ITSELF
IS THE BIGGEST QUESTION AT THIS TIME. THE NAM...EC...AND SREF-MEAN
ALL SUGGEST THE BOUNDARY WILL MOVE INTO NORTHERN OR CENTRAL PORTIONS
OF OUR CWA...WHILE THE OPERATIONAL GFS KEEPS THE BOUNDARY TO THE NORTH OF
OUR AREA. GIVEN THE UNCERTAINTY WITH RESPECT TO BOUNDARY
LOCATION...WENT NO HIGHER THAN 20-30% FOR THE DAY SUNDAY. CHANCES
FOR PRECIPITATION...ALBEIT LOW CHANCES DUE TO LOW CONFIDENCE...THEN
CONTINUE ACROSS MUCH OF OUR AREA SUNDAY NIGHT AS THE AXIS OF A
25-30KT 850MB JET STREAK DEVELOPS AND YET ANOTHER MID LEVEL
PERTURBATION POTENTIALLY MOVES OVER PORTIONS OF THE REGION. 20-30%
POPS REMAIN INTACT ACROSS THE AREA SUNDAY NIGHT AS A RESULT.
FINALLY...DURING THE DAY MONDAY...YET ANOTHER WEAK MID LEVEL
PERTURBATION MAY MOVE OVER THE AREA. CONFIDENCE IS LOW WITH RESPECT
TO ANY ONE LOCATION ACROSS THE AREA RECEIVING MEASURABLE
PRECIPITATION BUT RATHER THAN ELIMINATE POPS...WENT AHEAD AND
PRESENTED MOSTLY ~20% POPS TO MUCH OF OUR AREA FOR MONDAY.
MID LEVEL PERTURBATIONS MOVING OVER THE AREA WILL ALSO PROMOTE
CHANCES FOR PRECIPITATION ACROSS OUR AREA MONDAY NIGHT ONWARD AND AS
A RESULT...ALLBLEND PRESENTED POPS RANGING ANYWHERE FROM 20% TO 50%.
AFTER COORDINATION WITH SURROUNDING OFFICES...A FEW MINOR TWEAKS
WERE MADE TO TUESDAY POPS. OTHERWISE...ALLBLEND POPS WERE LEFT
UNCHANGED FOR THE MOST PART DUE TO THE LOW PROBABILITY OF IMPROVING
ON THE ALLBLEND SOLUTION.
DECENT LOW LEVEL MOISTURE...WITH SURFACE DEWPOINTS IN THE UPPER 60S
TO NEAR 70...WILL HELP PROMOTE RESPECTABLE LEVELS OF POTENTIAL
INSTABILITY BOTH SUNDAY AND MONDAY...WITH THE NAM AND OPERATIONAL GFS
BOTH SUGGESTING MUCAPE VALUES IN THE 2500-3500J/KG RANGE. DEEP LAYER
BULK SHEAR DOES NOT APPEAR AS THOUGH IT WILL BE OVERLY
IMPRESSIVE...GENERALLY IN THE 20-25KT RANGE...BUT GIVEN THE EXPECTED
POTENTIAL INSTABILITY WILL GO AHEAD AND OUTLOOK STRONG TO SEVERE
STORMS IN THE HWO FOR SUNDAY AND MONDAY. A SOMEWHAT DRIER LOW LEVEL
AIRMASS IS THEN EXPECTED TO INFILTRATE THE AREA TUESDAY ONWARD THUS
RESULTING IN LOWER POTENTIAL INSTABILITY VALUES. AS A RESULT...WILL
REFRAIN FROM ANY STRONG/SEVERE WEATHER WORDING IN THE HWO TUESDAY
AND BEYOND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 104 AM CDT SAT AUG 10 2013
EASING OFF THE REDUCED VISIBILITY FOR LATE TONIGHT AND EARLY
SATURDAY AS MOST LOCATIONS ARE NOT SHOWING MUCH DECLINE IN
VISIBILITY...AND ALSO...MODEL DATA ARE INDICATING THAT WE WILL NOT
TANK AS BADLY AS ONCE THOUGHT. THERE COULD BE A BIT OF A GUST FOR
SATURDAY AFTERNOON AND DECREASE SOMEWHAT FOR SATURDAY EVENING.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HEINLEIN
SHORT TERM...PFANNKUCH
LONG TERM...BRYANT
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS HASTINGS NE
135 AM CDT SAT AUG 10 2013
.UPDATE...
ISSUED AT 941 PM CDT FRI AUG 9 2013
TRIMMED BACK POPS FOR THE TONIGHT PERIOD...MAINLY TO AREAS
CONFINED TO OUR NORTHWESTERN COUNTIES. THESE SHOWERS SHOULD N0T
LAST PAST MIDNIGHT AS MESOSCALE ANALYSIS INDICATES AN INCREASE IN
CAPPING ACROSS AREAS WHERE CURRENT THUNDERSTORM ACTIVITY IS
ONGOING. ALSO TRIMMED BACK THE PATCHY FOG TO ACCOUNT FOR INCREASE
CLOUD COVER ACROSS OUR NORTH...WHICH SHOULD INHIBIT FOG IN THESE
AREAS. THE PATCHY FOG STILL INCLUDES THE TRI-CITIES AND AREAS
SOUTH OF I-80...WITH A TIME FRAME FROM ROUGHLY 08Z TO 13Z THIS
MORNING.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 345 PM CDT FRI AUG 9 2013
THE PRIMARY ISSUES DURING THE NEXT 24 HOURS INVOLVES ISOLATED AND
LIKELY NON-SEVERE SHOWER/STORM DEVELOPMENT INTO THIS
EVENING...AND WHETHER OR NOT ANY IMPACTFUL FOG MIGHT DEVELOP AGAIN
OVERNIGHT. HAVE MAINTAINED A SHOWER/STORM-FREE FORECAST CWA-WIDE
FROM LATE THIS EVENING THROUGH SATURDAY AFTERNOON.
20Z OBJECTIVE SURFACE ANALYSIS REVEALS A VERY SUBTLE...WEAK COLD
FRONT ALIGNED GENERALLY EAST-WEST ACROSS THE HEART OF THE NEB
CWA...ALTHOUGH ONE HAS TO LOOK PRETTY TO FIND IT...AS ALL IT
REALLY DOES IS SEPARATE A LIGHT EAST-NORTHEAST BREEZE FROM A LIGHT
EAST TO EAST-SOUTHEAST ONE. THIS LIGHT FLOW WITH SUSTAINED BREEZES
MOST ALL AREAS NO MORE THAN 5-10 MPH IS A RESULT OF BROAD SURFACE
HIGH PRESSURE OVER THE REGION...WITH THE CORE OF THE PARENT HIGH
AROUND 1027 MILLIBARS CENTERED WELL TO THE NORTH OVER
SASKATCHEWAN. ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL
DATA REVEALS RATHER WEAK FLOW ALOFT OVER THE CWA...GENERALLY
WESTERLY UP AT 300MB...NORTHERLY AT 500 MB...AND EVEN FARTHER DOWN
FROM THE EAST-NORTHEAST AT 700MB. ON THE LARGE SCALE...THE CENTRAL
PLAINS LIES IN THE INTERFACE BETWEEN A BROAD TROUGH AND EMBEDDED
VIGOROUS SHORTWAVE TRACKING EAST ACROSS SOUTHEAST CANADA...AND A
RIDGE AXIS EXTENDING EAST-WEST ACROSS THE SOUTHERN CONUS AND THEN
NORTHWARD INTO THE ROCKIES. ON A MORE REGIONAL LEVEL...A LOW-
AMPLITUDE MID LEVEL DISTURBANCE IS LIFTING OUT ACROSS EASTERN
KS/WESTERN MO. OTHER VERY SUBTLE DISTURBANCES APPEAR TO BE
RIPPLING OUT OF THE WY AREA TOWARD WESTERN NEB/SOUTHWEST SD...AND
HELPING TO KICK OFF STORMS IN THE NORTHERN PANHANDLE.
LOCALLY...JUST WITHIN THE PAST HOUR A FEW SMALL...ISOLATED
SHOWERS/POSSIBLY WEAK STORMS HAVE BUBBLED UP OVER DAWSON/BUFFALO
COUNTIES BUT HAVE SHOWED LITTLE SIGN OF MAINTAINING ORGANIZATION.
VISIBLE SATELLITE REVEALS PARTLY TO MOSTLY CLOUDY SKIES OVER THE
CWA AT MID-AFTERNOON...WITH A DECENT LOW LEVEL CUMULUS FIELD
ACROSS MUCH OF THE CENTRAL/WEST...AND SOME LINGERING HIGH CIRRUS
STILL GRADUALLY DEPARTING EASTERN COUNTIES. HIGH TEMPS APPEAR TO
BE FAIRLY WELL ON TRACK...WITH MOST AREAS LIKELY TO END UP IN THE
81-84 RANGE.
GOING FORWARD THROUGH THE LATE AFTERNOON HOURS THROUGH
03Z/10PM...HAVE OPTED TO KEEP THINGS SIMPLE AND ADVERTISE A SLIGHT
CHANCE OF SHOWERS/ISOLATED THUNDERSTORMS CWA-WIDE...ALTHOUGH WOULD
ANTICIPATE THE MOST LIKELY LOCALIZED DEVELOPMENT TO CONTINUE
TARGETING THE WESTERN HALF OF THE NEB CWA...WHERE LATEST MESO-
ANALYSIS INDICATES 0-1KM MLCAPE UP TO AROUND 1500 J/KG...AND WITH
LITTLE IF ANY CINH BUT ALSO VERY LIMITED FORCING FOR ASCENT. WITH
DEEP-LAYER SHEAR AVERAGING NO MORE THAN 15-20KT AND MID LEVEL
LAPSE RATES RATHER SHALLOW AT ONLY 5-6 C/KM...THE THREAT FOR
STRONG TO SEVERE STORMS APPEARS TO BE QUITE LIMITED IF NOT NON-
EXISTENT. POST-03Z/10PM...WILL AIM FOR A DRY REST OF THE
NIGHT...AS ANY DIURNAL SUPPORT FOR CONVECTION FROM AFTERNOON
HEATING WILL BE ON THE WANE...AND GIVEN THAT THE MAIN TRACK OF LOW
AMPLITUDE MID LEVEL DISTURBANCES OVERNIGHT SHOULD GENERALLY TARGET
THE NEB/SD BORDER AREA. FURTHERMORE...THE NOSE OF A MODEST 35KT
850MB LOW LEVEL JET CLEARLY AIMS INTO SOUTHERN SD/FAR NORTH CENTRAL
NEB OVERNIGHT...WHICH IS WHERE MOST MODELS INCLUDING THE NAM AND
4M WRF-NMM FOCUS CONVECTION. THAT BEING SAID...WILL HAVE TO KEEP
AN EYE ON THE NORTHWEST CWA AS THE LATEST HRRR MAINTAINS SOME
SANDHILLS CONVECTION WITHIN 50 MILES OF THE CWA THROUGH AROUND
MIDNIGHT...BUT FEEL THIS MAY BE A BIT CLOSER TO HOME THAN IT
ACTUALLY WILL BE. AT THE SURFACE TONIGHT...BREEZES WILL REMAIN
QUITE LIGHT AND AVERAGE UNDER 5 MPH...WHILE GRADUALLY TURNING TO A
SOUTHERLY DIRECTION. GIVEN THE LIGHT WIND SETUP...THERE IS AT
LEAST SOME CONCERN THAT FOG COULD AGAIN DEVELOP AND REDUCE
VISIBILITY TO 1 MILE OR LESS. HOWEVER...THE CONSENSUS OF
MODELS/GUIDANCE IS THAT TONIGHT/S FOG EVENT SHOULDN/T BE AS
DENSE/IMPACTFUL...POSSIBLY DUE TO SLIGHTLY BETTER BETTER MIXING
JUST ABOVE THE SURFACE. FOR NOW...WILL MAINTAIN THE GENERIC PATCHY
FOG MENTION CWA-WIDE FOR THE LATE NIGHT/EARLY MORNING HOURS
INTRODUCED BY THE PREVIOUS SHIFT...BUT WILL DEFER TO THE NEXT FEW
SHIFTS TO POTENTIALLY RAMP UP THIS FOG WORDING IF NEED BE. AS FOR
LOW TEMPS...ACTUALLY NUDGED DOWN 1-2 DEGREES FROM PREVIOUS IN MOST
SPOTS PER A GUIDANCE BLEND...WHICH PUTS MOST AREAS DOWN BETWEEN
57-61 DEGREES.
TURNING TO THE SATURDAY DAYTIME PERIOD 12Z-00Z/7AM-7PM...MAINTAINED
A RAIN-FREE FORECAST CWA-WIDE. IN THE MID/UPPER LEVELS...FAIRLY
WEAK TO MODEST WEST-NORTHWEST FLOW WILL MAINTAIN OVER THE CENTRAL
PLAINS AT/ABOVE 500MB...AND THERE SHOULD BE SOME SUBTLE HEIGHT
RISES AS WELL...AS THE SOUTHERN PLAINS/SOUTHERN ROCKIES RIDGE
EDGES NORTH JUST A BIT. THE PRIMARY MID LEVEL SHORTWAVE TROUGH
TRACK DURING THE DAY WILL BE FROM SD TOWARD SOUTHWEST MN/NORTHWEST
IA...AND THIS DISTURBANCE SHOULD TEAM WITH AN EAST-WEST QUASI-
STATIONARY FRONT SETTING UP NEAR THE NEB/SD BORDER TO FOCUS THE
VAST MAJORITY OF DAYTIME CONVECTION AT LEAST 50-100 MILES NORTH
AND POSSIBLY NORTHWEST OF THE CWA. THE ODDS OF CONVECTION FORMING
LOCALLY WITH DAYTIME HEATING SEEMS SMALLER THAN TODAY GIVEN
SLIGHTLY WARMER TEMPS EVIDENT AT 700MB...DESPITE MODEST MLCAPE
VALUES CLIMBING INTO THE 500-1000 J/KG RANGE PER THE 18Z NAM.
MODEL FORECASTS SOUNDINGS ALSO CLEARLY SHOW A WEAK BUT EVIDENT CAP.
OTHERWISE...ALTHOUGH BY NO MEANS WINDY...THE LATE MORNING-
AFTERNOON HOURS SHOULD FEATURE SOME OF THE MOST NOTICEABLE MODEST
BREEZES FELT IN MOST OF THE CWA IN SEVERAL DAYS...AS A TIGHTENED
PRESSURE GRADIENT TO THE EAST OF HIGH PLAINS LEE TROUGH SHOULD
PROMOTE SUSTAINED SOUTHERLY SPEEDS 10-15 MPH MOST AREAS. GIVEN THE
SOUTHERLY BREEZES...SLIGHTLY WARMER TEMPS AT 850MB...AND LIKELY NO
WORSE THAN PARTLY CLOUDY SKIES...SEE LITTLE REASON WHY HIGH TEMPS
SHOULDN/T BE AT LEAST A TOUCH HIGHER THAN TODAY. AS A
RESULT...NUDGED UP PREVIOUS HIGHS 1-2 DEGREES IN MOST AREAS...WITH
MOST OF THE CWA AIMED FOR FAIRLY UNIFORM HIGHS BETWEEN 83-86
DEGREES.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 344 PM CDT FRI AUG 9 2013
GUIDANCE SUGGESTS QUASI-ZONAL TO NORTHWESTERLY MID TO UPPER LEVEL
FLOW WILL PERSIST OVER THE CENTRAL PLAINS THROUGH MUCH OF THE LONG
TERM FORECAST PERIOD...WITH THE POSSIBILITY OF MULTIPLE MID LEVEL
PERTURBATIONS MOVING OVER THE AREA. PRECIPITATION CHANCES REMAIN
INTACT THROUGHOUT THE LONG TERM FORECAST PERIOD AS A RESULT.
STARTING SATURDAY NIGHT...THERE ARE SIGNS...PRIMARILY FROM THE
EC...OPERATIONAL GFS AND SREF-MEAN...THAT CENTRAL TO NORTHERN HIGH
PLAINS CONVECTION FROM SATURDAY AFTERNOON/EVENING MAY HOLD TOGETHER
LONG ENOUGH...PRIMARILY DUE TO LOW LEVEL THERMAL ADVECTION ALONG THE
AXIS OF A ~30KT 850MB JET STREAK...TO IMPACT NORTHERN PORTIONS OF
OUR CWA. CONFIDENCE IS NOT OVERLY HIGH THAT MEASURABLE PRECIPITATION
WILL BE REALIZED ACROSS OUR AREA SATURDAY NIGHT AND AS A
RESULT...POPS ONLY IN THE 20-30% RANGE CURRENTLY EXIST. HEADING INTO
THE DAY SUNDAY...LOW LEVEL CONVERGENCE ALONG A LOW LEVEL BAROCLINIC
ZONE/TROUGH COULD PROMOTE ENOUGH LIFT...ALONG WITH A PASSING MID
LEVEL PERTURBATION...TO PROMOTE PRECIPITATION PRODUCTION ACROSS
PORTIONS OF THE REGION. WHERE EXACTLY THE BOUNDARY POSITIONS ITSELF
IS THE BIGGEST QUESTION AT THIS TIME. THE NAM...EC...AND SREF-MEAN
ALL SUGGEST THE BOUNDARY WILL MOVE INTO NORTHERN OR CENTRAL PORTIONS
OF OUR CWA...WHILE THE OPERATIONAL GFS KEEPS THE BOUNDARY TO THE NORTH OF
OUR AREA. GIVEN THE UNCERTAINTY WITH RESPECT TO BOUNDARY
LOCATION...WENT NO HIGHER THAN 20-30% FOR THE DAY SUNDAY. CHANCES
FOR PRECIPITATION...ALBEIT LOW CHANCES DUE TO LOW CONFIDENCE...THEN
CONTINUE ACROSS MUCH OF OUR AREA SUNDAY NIGHT AS THE AXIS OF A
25-30KT 850MB JET STREAK DEVELOPS AND YET ANOTHER MID LEVEL
PERTURBATION POTENTIALLY MOVES OVER PORTIONS OF THE REGION. 20-30%
POPS REMAIN INTACT ACROSS THE AREA SUNDAY NIGHT AS A RESULT.
FINALLY...DURING THE DAY MONDAY...YET ANOTHER WEAK MID LEVEL
PERTURBATION MAY MOVE OVER THE AREA. CONFIDENCE IS LOW WITH RESPECT
TO ANY ONE LOCATION ACROSS THE AREA RECEIVING MEASURABLE
PRECIPITATION BUT RATHER THAN ELIMINATE POPS...WENT AHEAD AND
PRESENTED MOSTLY ~20% POPS TO MUCH OF OUR AREA FOR MONDAY.
MID LEVEL PERTURBATIONS MOVING OVER THE AREA WILL ALSO PROMOTE
CHANCES FOR PRECIPITATION ACROSS OUR AREA MONDAY NIGHT ONWARD AND AS
A RESULT...ALLBLEND PRESENTED POPS RANGING ANYWHERE FROM 20% TO 50%.
AFTER COORDINATION WITH SURROUNDING OFFICES...A FEW MINOR TWEAKS
WERE MADE TO TUESDAY POPS. OTHERWISE...ALLBLEND POPS WERE LEFT
UNCHANGED FOR THE MOST PART DUE TO THE LOW PROBABILITY OF IMPROVING
ON THE ALLBLEND SOLUTION.
DECENT LOW LEVEL MOISTURE...WITH SURFACE DEWPOINTS IN THE UPPER 60S
TO NEAR 70...WILL HELP PROMOTE RESPECTABLE LEVELS OF POTENTIAL
INSTABILITY BOTH SUNDAY AND MONDAY...WITH THE NAM AND OPERATIONAL GFS
BOTH SUGGESTING MUCAPE VALUES IN THE 2500-3500J/KG RANGE. DEEP LAYER
BULK SHEAR DOES NOT APPEAR AS THOUGH IT WILL BE OVERLY
IMPRESSIVE...GENERALLY IN THE 20-25KT RANGE...BUT GIVEN THE EXPECTED
POTENTIAL INSTABILITY WILL GO AHEAD AND OUTLOOK STRONG TO SEVERE
STORMS IN THE HWO FOR SUNDAY AND MONDAY. A SOMEWHAT DRIER LOW LEVEL
AIRMASS IS THEN EXPECTED TO INFILTRATE THE AREA TUESDAY ONWARD THUS
RESULTING IN LOWER POTENTIAL INSTABILITY VALUES. AS A RESULT...WILL
REFRAIN FROM ANY STRONG/SEVERE WEATHER WORDING IN THE HWO TUESDAY
AND BEYOND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 104 AM CDT SAT AUG 10 2013
EASING OFF THE REDUCED VISIBILITY FOR LATE TONIGHT AND EARLY
SATURDAY AS MOST LOCATIONS ARE NOT SHOWING MUCH DECLINE IN
VISIBILITY...AND ALSO...MODEL DATA ARE INDICATING THAT WE WILL NOT
TANK AS BADLY AS ONCE THOUGHT. THERE COULD BE A BIT OF A GUST FOR
SATURDAY AFTERNOON AND DECREASE SOMEWHAT FOR SATURDAY EVENING.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...GUERRERO
SHORT TERM...PFANNKUCH
LONG TERM...BRYANT
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1143 AM MDT THU AUG 8 2013
.AVIATION...
18Z TAF CYCLE
SHOWERS AND THUNDERSTORMS WILL FAVOR NORTH-CENTRAL AND NORTHEASTERN
NEW MEXICO THIS AFTERNOON AND EVENING WITH ISOLATED COVERAGE ELSEWHERE.
THE STRONGER SHOWERS AND THUNDERSTORMS WILL PRODUCE DOWNPOURS CAPABLE
OF REDUCING VISIBILITIES/CEILINGS BRIEFLY. CONVECTIVE COMPLEX OVER
NORTHEAST NM/SOUTHEAST CO WILL SEND A RAIN COOLED AIRMASS SOUTHWESTWARD
THROUGH THE PLAINS AND THROUGH THE CANYONS OF THE CENTRAL MTN CHAIN
LATE THIS EVENING. LIGHT TO MODERATE EAST/SOUTHEAST WINDS ARE
EXPECTED AT KSAF AND KABQ AROUND 06Z.
33
.PREV DISCUSSION...330 AM MDT THU AUG 8 2013...
SURFACE BOUNDARY ATTM IN APPROXIMATELY THE SAME LOCATION AS ONE 24
HOURS. STILL CONSIDERABLE MOISTURE LINGERING OVER THE STATE WITH
SIGNIFICANTLY DRIER DEWPOINTS AS WELL AS A MUCH DRIER AIR MASS
OVERALL ACROSS CENTRAL/WRN AZ. SOMEWHAT MORE ORGANIZED CLOUD COVER
ROTG SE OVER THE FOUR CORNERS REGION...AND RUC13 CONTINUES TO
ANALYZE A WEAK CLOSED CIRCULATION AT H5 OVER NW NM/SW CO THROUGH
EARLY THIS AFTERNOON. AS THE DAY PROGRESSES...A SURFACE BOUNDARY IS
FORECAST TO BECOME MORE DEFINED OVER NE NM. THEREFORE HAVE TRENDED
TOWARDS THE HIGHER GUIDANCE POPS TODAY FOR THE NORTHEAST THIRD TO
HALF OF THE FORECAST AREA. LATEST SPC OUTLOOK HAS SLIGHT RISK FOR
SVR STORMS IN AN AREA SIMILAR TO WHAT WAS PREDICTED 24 HOURS AGO.
HAVE NOT HIGHLIGHTED THAT POSSIBILITY IN THE WX GRIDS...SO LATER
SHIFTS WILL NEED TO MONITOR.
FRONT TO PLUNGE INTO THE EASTERN PLAINS TONIGHT BUT NOT MUCH
INDICATION MODEL WISE IT WILL REACH THE RGV. FRIDAY NIGHT APPEARS AS
IF THIS POSSIBILITY IS MORE LIKELY...TRENDING SHOWER AND STORM
CHANCES UPWARD AND WESTWARD. HIGHS TODAY WILL BE A FEW DEGREES
BELOW AVERAGE MAINLY NORTH OF INTERSTATE 40...AND MAINLY OVER THE
NORTHEAST QUARTER FRIDAY. WITH POTENTIAL FORECAST FOR A MONSOON
BURST...HIGHS SATURDAY ACROSS THE NORTHWEST HALF WILL BE SEVERAL
DEGREES BELOW AVERAGE.
ANOTHER TRANSITION FORECAST IN THE WEATHER PATTERN FOR NEXT
WEEK...WITH A TREND TOWARDS WARMER AND DRIER. THE UPPER HIGH CENTER
DRIFTS BACK OVER NEW MEXICO...AND FAR ENOUGH WESTWARD TO PUT THE
NORTHEAST UNDER NORTHWEST FLOW AS LEAST FOR A DAY OR TWO.
.FIRE WEATHER...
BACK DOOR COLD FRONT HAS MOVED INTO THE EASTERN PLAINS WITH A
REINFORCEMENT OF THIS BOUNDARY EXPECTED FRIDAY NIGHT. CURRENTLY THE
REMNANTS OF THE UPPER LOW FROM AZ CONTINUE TO BECOME LESS ORGANIZED
OVER SOUTHERN CO. MOISTURE AND LINGERING ENERGY FROM THE LEFTOVER
DISTURBANCE WILL KEEP THE BEST WETTING RAIN CHANCES OVER NORTH
CENTRAL TO NORTHEASTERN NM TODAY. MODELS CONTINUE TO ADVERTISE DRIER
AIR WORKING IN FROM THE WEST TODAY...AND WATER VAPOR SATELLITE
IMAGERY SUPPORTS THIS. THEREFORE...EXPECT MINIMAL SHOWER/STORM
COVERAGE IN THE CENTRAL TO WEST CENTRAL AND NORTHWESTERN ZONES
TODAY. MINIMUM RH WILL STILL STAY AOA 20 PERCENT WITH MODERATE
SURFACE BREEZES EXHIBITING A NORTHWESTERLY COMPONENT OVER MUCH OF
THE FORECAST AREA. EXCELLENT RH RECOVERY IS EXPECTED OVER THE
NORTHEASTERN HALF OF THE FORECAST AREA TONIGHT WITH STILL GOOD
RECOVERY OF 60-80 PERCENT FARTHER WEST. CONVECTION FROM THE LATE
EVENING MAY ATTEMPT TO SHOVE AN EAST WIND BEYOND THE CENTRAL
MOUNTAIN CHAIN TONIGHT...BUT MODELS ARE NOT ENTHUSIASTIC ABOUT IT.
AT THIS TIME NO STRONG GAP/CANYON WINDS HAVE BEEN BUILT INTO THE
FORECAST THROUGH FRIDAY MORNING.
MOISTURE WILL HAVE AT LEAST WORKED TOWARD THE CENTRAL MOUNTAIN CHAIN
EARLY ON FRIDAY WITH THE AFOREMENTIONED EASTERLY WINDS...AND THIS
MOISTURE PUSH WILL CONTINUE WESTWARD INTO THE AFTERNOON. STORMS WILL
BECOME A BIT MORE WIDESPREAD ALONG THE CENTRAL MOUNTAIN CHAIN AND
TOWARD THE CONTINENTAL DIVIDE AS TEMPERATURES WARM CLOSE TO AVERAGE
IN MOST ZONES. LOWEST MINIMUM RH VALUES WILL BE IN THE SAN JUAN
BASIN FRIDAY WHERE VALUES WILL SLIP TO 20 PERCENT OR JUST SLIGHTLY
BELOW. ANY CONVECTION LATE FRIDAY EAST OF THE CENTRAL MOUNTAINS WILL
AID THE PUSH OF A REINFORCING BACK DOOR FRONT. THIS WILL CONTINUE TO
CARRY MOISTURE WESTWARD WHILE ALSO PRODUCING MODERATE TO STRONG
GAP/CANYON WINDS NEAR CENTRAL VALLEY LOCATIONS THROUGH SATURDAY
MORNING.
BETTER LOW LAYER MOISTURE TRANSPORTED FROM THE EAST WILL COUPLE WITH
A MID LEVEL MONSOON PLUME SQUEEZING INTO NM...AND THIS WILL SET THE
STAGE FOR AN ACTIVE THUNDERSTORM DAY SATURDAY. NAM MODEL IS MOST
BULLISH WITH WETTING PRECIP CHANCES AND CONSEQUENTLY BOASTS MUCH
COOLER TEMPERATURES WHICH WOULD CERTAINLY MITIGATE ANY FIRE WX
CONCERNS. PLENTY OF LEFTOVER MOISTURE TO RECYCLE ON SUNDAY WILL ALSO
YIELD A GOOD CROP OF STORMS. INTO NEXT WEEK THE UPPER HIGH IS STILL
DEPICTED AS MOVING WESTWARD OVER OR CLOSE TO NM WHILE ELONGATING
SOME ON A WEST-EAST AXIS. ANOTHER BACK DOOR FRONT IN THE NORTHEAST
COULD KEEP CONVECTIVE ACTIVITY GOING IN THE NORTHEAST LATE TUESDAY.
52
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHY
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
528 AM MDT THU AUG 8 2013
.AVIATION...
12Z TAF CYCLE
SOME PATCHES OF LOW STRATUS CLOUDS AND FOG HAVE DEVELOPED OVER
SELECT PARTS OF NORTHERN NEW MEXICO...MAINLY WHERE HEAVIER RAIN
FELL YESTERDAY AND BEST LOW LAYER MOISTURE IS. GREATEST POTENTIAL
FOR MVFR/IFR CONDITIONS WILL BE IN THE NORTHEASTERN HIGHLANDS TO
NORTHEASTERN PLAINS...NEAR KLVS...KAXX...KRTN... KCAO...AND KTCC.
ANY LOW CLOUDS WILL BURN OFF BY 08/1600UTC. SHOWERS AND STORMS
WILL THEN FAVOR NORTH CENTRAL TO NORTHEASTERN SECTIONS OF NEW
MEXICO THIS AFTERNOON AND EVENING WITH MINIMAL COVERAGE
ELSEWHERE. BREEZES WILL REMAIN LIGHT TO MODERATE OUTSIDE OF
THUNDERSTORM OUTFLOWS...AND ANY STORM DOWNPOURS WILL BE CAPABLE OF
REDUCING VISIBILITIES/CEILINGS BRIEFLY.
52
&&
.PREV DISCUSSION...330 AM MDT THU AUG 8 2013...
SURFACE BOUNDARY ATTM IN APPROXIMATELY THE SAME LOCATION AS ONE 24
HOURS. STILL CONSIDERABLE MOISTURE LINGERING OVER THE STATE WITH
SIGNIFICANTLY DRIER DEWPOINTS AS WELL AS A MUCH DRIER AIR MASS
OVERALL ACROSS CENTRAL/WRN AZ. SOMEWHAT MORE ORGANIZED CLOUD COVER
ROTG SE OVER THE FOUR CORNERS REGION...AND RUC13 CONTINUES TO
ANALYZE A WEAK CLOSED CIRCULATION AT H5 OVER NW NM/SW CO THROUGH
EARLY THIS AFTERNOON. AS THE DAY PROGRESSES...A SURFACE BOUNDARY IS
FORECAST TO BECOME MORE DEFINED OVER NE NM. THEREFORE HAVE TRENDED
TOWARDS THE HIGHER GUIDANCE POPS TODAY FOR THE NORTHEAST THIRD TO
HALF OF THE FORECAST AREA. LATEST SPC OUTLOOK HAS SLIGHT RISK FOR
SVR STORMS IN AN AREA SIMILAR TO WHAT WAS PREDICTED 24 HOURS AGO.
HAVE NOT HIGHLIGHTED THAT POSSIBILITY IN THE WX GRIDS...SO LATER
SHIFTS WILL NEED TO MONITOR.
FRONT TO PLUNGE INTO THE EASTERN PLAINS TONIGHT BUT NOT MUCH
INDICATION MODEL WISE IT WILL REACH THE RGV. FRIDAY NIGHT APPEARS AS
IF THIS POSSIBILITY IS MORE LIKELY...TRENDING SHOWER AND STORM
CHANCES UPWARD AND WESTWARD. HIGHS TODAY WILL BE A FEW DEGREES
BELOW AVERAGE MAINLY NORTH OF INTERSTATE 40...AND MAINLY OVER THE
NORTHEAST QUARTER FRIDAY. WITH POTENTIAL FORECAST FOR A MONSOON
BURST...HIGHS SATURDAY ACROSS THE NORTHWEST HALF WILL BE SEVERAL
DEGREES BELOW AVERAGE.
ANOTHER TRANSITION FORECAST IN THE WEATHER PATTERN FOR NEXT
WEEK...WITH A TREND TOWARDS WARMER AND DRIER. THE UPPER HIGH CENTER
DRIFTS BACK OVER NEW MEXICO...AND FAR ENOUGH WESTWARD TO PUT THE
NORTHEAST UNDER NORTHWEST FLOW AS LEAST FOR A DAY OR TWO.
.FIRE WEATHER...
BACK DOOR COLD FRONT HAS MOVED INTO THE EASTERN PLAINS WITH A
REINFORCEMENT OF THIS BOUNDARY EXPECTED FRIDAY NIGHT. CURRENTLY THE
REMNANTS OF THE UPPER LOW FROM AZ CONTINUE TO BECOME LESS ORGANIZED
OVER SOUTHERN CO. MOISTURE AND LINGERING ENERGY FROM THE LEFTOVER
DISTURBANCE WILL KEEP THE BEST WETTING RAIN CHANCES OVER NORTH
CENTRAL TO NORTHEASTERN NM TODAY. MODELS CONTINUE TO ADVERTISE DRIER
AIR WORKING IN FROM THE WEST TODAY...AND WATER VAPOR SATELLITE
IMAGERY SUPPORTS THIS. THEREFORE...EXPECT MINIMAL SHOWER/STORM
COVERAGE IN THE CENTRAL TO WEST CENTRAL AND NORTHWESTERN ZONES
TODAY. MINIMUM RH WILL STILL STAY AOA 20 PERCENT WITH MODERATE
SURFACE BREEZES EXHIBITING A NORTHWESTERLY COMPONENT OVER MUCH OF
THE FORECAST AREA. EXCELLENT RH RECOVERY IS EXPECTED OVER THE
NORTHEASTERN HALF OF THE FORECAST AREA TONIGHT WITH STILL GOOD
RECOVERY OF 60-80 PERCENT FARTHER WEST. CONVECTION FROM THE LATE
EVENING MAY ATTEMPT TO SHOVE AN EAST WIND BEYOND THE CENTRAL
MOUNTAIN CHAIN TONIGHT...BUT MODELS ARE NOT ENTHUSIASTIC ABOUT IT.
AT THIS TIME NO STRONG GAP/CANYON WINDS HAVE BEEN BUILT INTO THE
FORECAST THROUGH FRIDAY MORNING.
MOISTURE WILL HAVE AT LEAST WORKED TOWARD THE CENTRAL MOUNTAIN CHAIN
EARLY ON FRIDAY WITH THE AFOREMENTIONED EASTERLY WINDS...AND THIS
MOISTURE PUSH WILL CONTINUE WESTWARD INTO THE AFTERNOON. STORMS WILL
BECOME A BIT MORE WIDESPREAD ALONG THE CENTRAL MOUNTAIN CHAIN AND
TOWARD THE CONTINENTAL DIVIDE AS TEMPERATURES WARM CLOSE TO AVERAGE
IN MOST ZONES. LOWEST MINIMUM RH VALUES WILL BE IN THE SAN JUAN
BASIN FRIDAY WHERE VALUES WILL SLIP TO 20 PERCENT OR JUST SLIGHTLY
BELOW. ANY CONVECTION LATE FRIDAY EAST OF THE CENTRAL MOUNTAINS WILL
AID THE PUSH OF A REINFORCING BACK DOOR FRONT. THIS WILL CONTINUE TO
CARRY MOISTURE WESTWARD WHILE ALSO PRODUCING MODERATE TO STRONG
GAP/CANYON WINDS NEAR CENTRAL VALLEY LOCATIONS THROUGH SATURDAY
MORNING.
BETTER LOW LAYER MOISTURE TRANSPORTED FROM THE EAST WILL COUPLE WITH
A MID LEVEL MONSOON PLUME SQUEEZING INTO NM...AND THIS WILL SET THE
STAGE FOR AN ACTIVE THUNDERSTORM DAY SATURDAY. NAM MODEL IS MOST
BULLISH WITH WETTING PRECIP CHANCES AND CONSEQUENTLY BOASTS MUCH
COOLER TEMPERATURES WHICH WOULD CERTAINLY MITIGATE ANY FIRE WX
CONCERNS. PLENTY OF LEFTOVER MOISTURE TO RECYCLE ON SUNDAY WILL ALSO
YIELD A GOOD CROP OF STORMS. INTO NEXT WEEK THE UPPER HIGH IS STILL
DEPICTED AS MOVING WESTWARD OVER OR CLOSE TO NM WHILE ELONGATING
SOME ON A WEST-EAST AXIS. ANOTHER BACK DOOR FRONT IN THE NORTHEAST
COULD KEEP CONVECTIVE ACTIVITY GOING IN THE NORTHEAST LATE TUESDAY.
52
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BISMARCK ND
149 AM CDT SAT AUG 10 2013
.UPDATE...
ISSUED AT 149 AM CDT SAT AUG 10 2013
WILL EXPAND THE AERIAL COVERAGE OF CHANCES FOR SHOWERS OVER THE
SOUTHWEST THIS MORNING. MODELS KEYING IN ON PRECIPITATION
DEVELOPMENT 9-12Z ASSOCIATED WITH THE S/WV OVER SOUTHEAST MONTANA.
DO NOT ANTICIPATE THUNDER WITH ALL INSTABILITY SOUTHWEST OF THIS
AREA. OTHER EDITS THROUGH 12Z MAINLY FOR ADJUSTING HOURLY TRENDS.
UPDATE ISSUED AT 906 PM CDT FRI AUG 9 2013
MAIN UPDATE THIS EVENING WAS TO REMOVE MENTION OF PRECIPITATION
THROUGH AT LEAST 08Z SATURDAY IN THE FAR SOUTHWEST. ALSO
REDUCED/DELAYED POPS SATURDAY MORNING ACROSS FAR SOUTH CENTRAL
NORTH DAKOTA. THE LATEST HIGH RESOLUTION MODELS (HRRR/RAP) ALONG
WITH THE 00Z NAM...ARE ALL INITIALIZING/INDICATING PRECIPITATION
IN AREAS WHERE...IN REALITY...NOTHING IS OCCURRING. THE MODELS
ALREADY HAVE PRECIPITATION EITHER UP TO AND/OR IN OUR SOUTHWEST
ZONES AS OF 01Z. BUT THIS IS NOT THE CASE...HENCE THEIR SOLUTIONS
ARE PRETTY MUCH OBSOLETE FOR THE OVERNIGHT PERIOD AND INTO
SATURDAY MORNING. THE GFS/ECMWF ACTUALLY HAVE THE BEST HANDLE ON
THE CURRENT PRECIPITATION AREA...AND BOTH MODELS KEEP THE BEST
LIFT/OMEGA/PRECIPITATION SOUTH OF OUR BORDER TONIGHT. A SHORTWAVE
IS FORECAST TO MOVE ALONG THE MONTANA/WYOMING BORDER OVERNIGHT
WITH VERTICAL MOTION FIELD CONCENTRATED IN SOUTH DAKOTA. THUS
SCALED BACK POPS...AND REMOVED MENTION OF THUNDER IN FAR SOUTH
CENTRAL NORTH DAKOTA UNTIL SATURDAY AFTERNOON...AS ONLY THE FAR
SOUTHWEST WOULD BE VULNERABLE TO THUNDER LATE TONIGHT THROUGH
SATURDAY MORNING.
UPDATE ISSUED AT 541 PM CDT FRI AUG 9 2013
THE LATEST WATER VAPOR IMAGERY SHOWS NORTHERN/CENTRAL NORTH DAKOTA
DOMINATED BY NORTHWEST FLOW ALOFT...WHILE FAR SOUTHWEST/SOUTHERN
NORTH DAKOTA ARE BECOMING DETACHED FROM THE DOMINATE NORTHWEST FLOW.
HERE...WEAK RIDGING WAS OBSERVED ON WATER VAPOR WHICH EXTENDED FROM
THE FRONT RANGE OF THE ROCKIES INTO THE PANHANDLE OF IDAHO. THIS IS
INDUCING A WEST TO WEAK NORTHWEST FLOW. COUPLE OF SHORTWAVES TO NOTE
FOR TONIGHT/SATURDAY...THE FIRST WAS ALONG THE NORTHERN WYOMING AND
MONTANA BORDER...A SECOND IN CENTRAL IDAHO...AND A THIRD IN EAST
CENTRAL ALBERTA. THESE SHORTWAVES WILL TOP THE RIDGE AND SHIFT EAST
TONIGHT/SATURDAY. THE STRONGEST OMEGA/LIFT FOR TONIGHT AND SATURDAY
REMAINS IN SOUTH DAKOTA...BUT DOES GRAZE WESTERN AND SOUTHERN NORTH
DAKOTA LATER TONIGHT THROUGH SATURDAY. THE LATEST HRRR REFLECTIVITY
SUGGESTS THAT CONVECTION NOW OVER SOUTH CENTRAL MONTANA WILL SHIFT
EAST TONIGHT ALLOWING FOR THE POSSIBILITY OF ISOLATED SHOWERS IN
THE FAR SOUTHWEST AND EDGING FAIRLY CLOSE TO OUR FAR SOUTH CENTRAL
ZONES...MAINLY TOWARD AND AFTER 05Z SATURDAY. WILL CONTINUE TO
WATCH THIS ACTIVITY THIS EVENING. LATEST BOWMAN RADAR IS JUST
BEGINNING TO SHOW SOME WEAK REFLECTIVITY`S IN FAR SOUTHEAST
MONTANA. FOR THIS UPDATE...HAVE INCREASED SKY GRIDS FOR THE EARLY
PART OF THIS EVENING BASED ON VISIBLE SATELLITE AND SURFACE
OBSERVATIONS. REST OF THE FORECAST HAS THE TRENDS HANDLED WELL.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 339 PM CDT FRI AUG 9 2013
THE MAIN FORECAST ISSUE IN THE NEAR TERM IS PRECIPITATION CHANCES
TONIGHT AND SATURDAY. A WARM FRONT WILL LIFT NORTH INTO SOUTH
DAKOTA TONIGHT AS A SHORT WAVE TROUGH TOPS THE UPPER RIDGE. RAIN
COVERAGE IS EXPECTED TO REMAIN RATHER LIMITED ACROSS THE SOUTHERN
COUNTIES SO 20/30 POPS SEEM REASONABLE. SHOWERS AND ISOLATED
STORMS WILL LIKELY PUSH A BIT FARTHER NORTH INTO THE STATE ON
SATURDAY AFTERNOON. THERE SHOULD BE ENOUGH ELEVATED INSTABILITY TO
SUPPORT A FEW THUNDERSTORMS...BUT NO SEVERE WEATHER IS ANTICIPATED.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 339 PM CDT FRI AUG 9 2013
THE EXTENDED WILL BE CHARACTERIZED BY A MID/UPPER LEVEL RIDGE SLOWLY
BUILDING FROM THE ROCKIES EARLY IN THE PERIOD INTO THE CENTRAL
PLAINS BY THE END OF THE PERIOD. THIS WILL GENERATE A GRADUAL
WARMING TREND TO NEAR NORMAL TEMPERATURES BY FRIDAY.
LINGERING CONVECTION ALONG AND SOUTH OF I-94 SATURDAY EVENING SHOULD
WANE WITH THE LOSS OF DAYTIME HEATING.
AS A MID/UPPER RIDGE BUILDS INTO THE REGION...UPPER LEVEL DYNAMICS
WILL BE ON THE DECREASE. HOWEVER...LINGERING MOISTURE AND
INSTABILITY WILL GENERATE A SLIGHT CHANCE OF DIURNALLY DRIVEN
CONVECTION PRIMARILY ALONG AND WEST OF THE MISSOURI RIVER DURING THE
AFTERNOON/EVENING HOURS SUNDAY THROUGH WEDNESDAY.
THE UPPER RIDGE IS PROGGED TO BREAK DOWN SOMEWHAT THURSDAY AS A
RIDGE RUNNER CRESTS OVER THE ANTICYCLONIC RIDGE AXIS. FOR NOW
INDICATED SLIGHT CHANCE POPS AREAWIDE. HOWEVER...POPS MAY NEED TO BE
INCREASED IF FUTURE RUNS ADD CREDENCE TO THE 12Z SUITE OF MODEL
GUIDANCE.
THE RIDGE RUNNER SHORTWAVE IS THEN PROGGED TO PUSH EAST OF THE REGION
FRIDAY WITH PRECIP CHANCES ENDING FROM WEST TO EAST. HIGHS FRIDAY
LOOK TO RANGE FROM THE LOWER 80S EAST TO THE UPPER 80S WEST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 149 AM CDT SAT AUG 10 2013
VFR CONDITIONS THROUGH THE 06Z TAF PERIOD. WILL SEE A CHANCE FOR
SHOWERS OR AN ISOLATED THUNDERSTORM ALL TERMINALS AT SOME POINT IN
THE PERIOD.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...RP KINNEY
LONG TERM...TM
AVIATION...NH
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1156 PM CDT FRI AUG 9 2013
.UPDATE...FOR 06Z AVIATION.
&&
.AVIATION...06Z TAF DISCUSSION.
LONE SHOWER IN MIDDLE TENNESSEE FINALLY COMING TO AN END NEAR
ISSUANCE TIME. WARM FRONT REMAINS DRAPED ACROSS NORTHERN MIDDLE
PORTIONS OF THE STATE AND HAS BEEN THE FOCUS FOR CONVECTION THIS
EVENING. THIS WILL CONTINUE TO BE THE CASE...HELPING TO SPARK
MORE SH/TS BY LATE MORNING...AS WELL AS HELP TO DROP FLIGHT
CATEGORIES LATER TONIGHT. SHOULD SEE IFR CONDITIONS AT
CSV/CKV...WITH INCREASE BACK TO VFR BY LATE MORNING. WINDS WILL
ACTUALLY SHIFT TO THE NW...AND IN SOME CASES NORTHERLY...AS THE
FRONT SAGS INTO THE SOUTHERN PORTIONS OF THE STATE ON SATURDAY.
UNGER
&&
.PREV DISCUSSION... /ISSUED 819 PM CDT FRI AUG 9 2013/
UPDATE...SCATTERED CONVECTION HAS BEEN TRENDING DOWNWARD IN
COVERAGE AND INTENSITY...AND SEE NO REASON FOR THIS TO CHANGE
THROUGH LATE EVENING. HAVE LOWERED POPS AND QPF ACROSS THE AREA
TO INDICATE "SCATTERED" THUNDERSTORMS OVERNIGHT AND AVERAGE
RAINFALL AMOUNTS UNDER ONE QUARTER INCH. OF COURSE...WITH THE VERY
MOIST AIR MASS STILL IN PLACE...LOCALIZED HEAVY RAINFALL IS STILL
A POSSIBILITY. SHORT RANGE MODELS INCLUDING LATEST HRRR SHOW ONLY
SCATTERED AT BEST OVERNIGHT...BUT DO HINT AT INCREASING ACTIVITY
TOWARD DAYBREAK COMING IN FROM THE NORTHWEST AS THE QUASI
STATIONARY FRONT DIPS A LITTLE CLOSER AND A SHEARING UPPER WAVE
APPROACHES. STILL EXPECT ACTIVITY TO BECOME MORE WIDESPREAD ON
SATURDAY WITH FRONT OVER THE REGION.
13
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
27
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
420 AM CDT SAT AUG 10 2013
.DISCUSSION...
COASTAL RADARS SHOW SCATTERED SHOWERS AND THUNDERSTORMS IN THE
GULF WATERS THIS MORNING. AIRMASS ALONG THE COAST AND IN THE NW
GULF HAS BECOME VERY MOIST WITH GOES SOUNDER PRECIP WATER IMAGERY
SHOWING 2-2.2 INCHES WHERE CONVECTION IS ONGOING. WATER VAPOR
IMAGERY SHOWS UPPER LOW IN THE EAST CENTRAL GULF WHICH WILL
CONTINUE TO MOVE WEST ACROSS THE GULF AND DRIVE DEEPER MOISTURE
INLAND TODAY. UPPER LEVEL RIDGE HAS WEAKENED SOME BUT STRETCHES
ACROSS TEXAS THROUGH THE SE US. THINK SUBSIDENCE FROM THE RIDGE
MAY HOLD OFF CONVECTION INLAND FOR A LITTLE WHILE THIS MORNING BUT
DAY TIME HEATING WILL BE TOO MUCH FOR SCATTERED SHOWERS AND
THUNDERSTORMS NOT TO FORM. THE 06Z HRRR SHOWS CONVECTIVE
DEVELOPMENT ALONG THE COAST MAINLY 14-18Z AND THEN SCATTERED
ACTIVITY FURTHER INLAND FROM 18-21Z. THINK POPS OF 40 ALONG THE
COAST TRIMMING TO 20 FAR INLAND LOOKS ON TRACK. MIGHT BE ENOUGH
ACTIVITY TO BRING 50 POPS INLAND ALONG THE COAST BUT WILL HOLD OFF
TO SEE WHAT KIND OF COVERAGE DEVELOPS THROUGH THE MORNING.
CONVECTION FOR SUNDAY COULD BE ABOUT THE SAME COVERAGE AS TODAY
BUT PERHAPS A LITTLE LESS. MOISTURE WILL NOT BE AS HIGH WITH
PRECIP WATER AROUND 1.9-2 INCHES INSTEAD OF 2.2 INCHES.
NAM/GFS/ECMWF ARE ALL IN PRETTY GOOD AGREEMENT WITH THE CENTER OF
THE UPPER LOW TRACKING TOWARDS THE RIO GRANDE VALLEY ON SUNDAY.
VORTICITY WITH THE SYSTEM ALSO WEAKENS AND SHEARS OUT AS IT MOVES
INLAND. STILL THINK 30/40 POPS LOOK ON TRACK WITH 20 POPS FOR MORE
INLAND AREAS. BUT IF NAM IS MORE RIGHT...COULD HAVE MORE ACTIVITY
ON SUNDAY THAN TODAY. THINK THE NAM IS OVERDOING THE CONVECTION ON
SUNDAY AS UPPER LEVEL SUPPORT WILL NOT BE AS FAVORABLE.
THINK RAIN CHANCES WILL BE LESS ON MONDAY WITH 20 POPS IN PLACE.
THERE IS STILL DECENT MOISTURE WITH PRECIP WATER OF 1.9 INCHES BUT
THE RIDGE MAY BEGIN TO RE-ESTABLISH ITSELF OVER TX AT THIS TIME.
AGAIN LOOKS LIKE DAY TIME HEATING WILL BE THE MAIN TRIGGER FOR
CONVECTION BUT MOST LIKELY TIME WILL BE DURING THE AFTERNOON.
THE MAIN HAZARDS THE NEXT COUPLE OF DAYS WILL BE BRIEF HEAVY
RAINFALL AND LIGHTNING. COULD SEE SOME GUSTY WINDS BUT OVERALL NOT
A SEVERE THREAT. RAINFALL AMOUNTS THROUGH THE WEEKEND WILL LIKELY
BE AROUND A QUARTER TO HALF INCH WITH ISOLATED 1 INCH AMOUNTS IN
STRONGER STORMS. RAINFALL WILL PROVIDE SOME AREAS WITH A LITTLE
BREAK IN THE DROUGHT BUT NO REAL RELIEF. THEN AGAIN THERE COULD BE
SOME AREAS THAT DO NOT PICK UP ANY RAINFALL FROM THIS ENVIRONMENT.
NONETHELESS THE CLOUD COVER SHOULD HELP KEEP TEMPS LOWER AND AS A
RESULT WILL NOT NEED A HEAT ADVISORY FOR TODAY. WE WILL BE BACK TO
NEEDING 2 CONSECUTIVE DAYS OF A 108F HEAT INDEX TO ISSUE AN
ADVISORY.
THERE DOES LOOK TO BE A PATTERN CHANGE FOR THE EXTENDED FORECAST.
UPPER LEVEL RIDGE SHOULD BUILD OVER TX TUE/WED BUT THEN BECOMES
MORE ESTABLISHED OVER THE S ROCKIES BY THUR. TROUGHING OVER THE
GREAT LAKES WILL STRETCH TOWARDS THE MISS RIVER VALLEY SO NW FLOW
ALOFT MAY SUPPORT A FRONT PUSHING INTO THE AREA. GFS/ECMWF ARE
SHOWING A STRONGER FRONT MOVING INTO THE AREA THUR/FRI NEXT WEEK
SO WILL KEEP SOME RAIN CHANCES IN THE FORECAST ASSOCIATED WITH THE
FRONT. DRIER AIR MAY KNOCK MIN/MAX TEMPS DOWN A COUPLE OF DEGREES.
MODELS AGREE WITH AMPLIFYING THE PATTERN NEXT WEEKEND SO THIS
PATTERN MAY PERSIST A BIT LONGER AND GIVE SE TX A DECENT BREAK
FROM THE HEAT.
39
&&
.MARINE...
SCATTERED SHOWERS ONGOING ACROSS THE COASTAL WATERS THIS MORNING
AS A WEAK EASTERLY WAVE APPROACHES THE REGION. THIS FEATURE AND
ANOTHER DISTURBANCE EXPECTED ON SUNDAY WILL KEEP SCATTERED SHOWERS
AND THUNDERSTORMS ACROSS THE MARINE ZONES THROUGH THE WEEKEND. 38
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 99 78 97 75 97 / 20 20 20 20 20
HOUSTON (IAH) 95 78 95 77 95 / 40 20 40 20 20
GALVESTON (GLS) 90 82 90 81 91 / 40 20 40 20 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...39
AVIATION/MARINE...38
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1126 PM CDT FRI AUG 9 2013
.DISCUSSION...
/See Aviation Discussion below/
&&
.AVIATION...
Showers and thunderstorms at all airport locations in the forecast
area have dissipated due to nighttime ground cooling. Mostly VFR
flying conditions will prevail the next 24 hours across the forecast
area.
A weak cold front currently along a line from near Brady to Sonora
is slowing down as it tries to push through the forecast area. Winds
north of the front have become northerly or northeasterly at 5 to
10kt.
The GFS model forecasts the front to continue to move south past the
forecast area by tomorrow morning and then stalls the front and then
lifts the front north back into the forecast area by Saturday night,
developing a few showers along the front. Similarly the NAM model
lingers the front across southern counties...and in association with
afternoon heating...flares up scattered showers and thunderstorms
along the stalled front in the vicinity of Junction...Sonora and
Brady airports. Current TAFS reflect a combination of both models
because the front has slowed its southeastward motion based on
satellite and radar imagery with a position expected to be between
both model forecasts.
.PREV DISCUSSION... /ISSUED 620 PM CDT FRI AUG 9 2013/
.DISCUSSION...
/See Aviation Discussion below/
&&
.AVIATION...
Primary aviation concerns the next 3 to 4 hours are local areas of
showers and isolated thunderstorms that may product gusty
surface winds to 45kt...brief heavy rain and hazardous lightning.
Currently some showers and thunderstorms...with measured
lightning...are noted in Shackelford...Jones...Coke and Sterling
counties.
Showers are associated with a very weak frontal boundary stretching
from east-northeast to west-southwest through Jones and Sterling
Counties. Satellite imagery...radar imagery and models concur...the
front will move slowly toward the south-southeast the next 24 hours
weakening as it goes...then nearly dissipate southeast of Junction
and Kimble County on Saturday. Winds across Junction... Sonora...
San Angelo and Brady will shift from light southerly ahead of the
front to light northerly as the front passes to the southeast.
.PREV DISCUSSION... /ISSUED 307 PM CDT FRI AUG 9 2013/
.SHORT TERM...
.Tonight and Saturday...
Isolated severe thunderstorms with damaging winds possible again
this afternoon and evening. The best potential will be in the Big
Country, along a weak cold front along the I-20 corridor.
Discussion:
Conditions are similar to yesterday with an inverted V sounding.
Instability was fairly high. RAP ML CAPES ranged from 2000-3000 J/KG
in the Big Country and Concho Valley, with the highest values near
Sweetwater. Focus for initial storm development will be a weak front
along the I-20 corridor...although a few storms will likely develop
farther south along thunderstorm outflow boundaries. Main
thunderstorm threat will be damaging winds. With weak steering
currents, storm movement will be slow. This may also bring
localized flooding in urban areas.
The front is expected to move south Saturday afternoon...becoming
stationary somewhere along the I-10 corridor...although placement is
uncertain. The main threat will be strong gusty winds and dangerous
lightning.
.LONG TERM...
.Saturday Night...
Slight chance of storms will linger into the evening hours.
Whatever is left of the weak cold front will remain somewhere across
West Central Texas, along with whatever outflow boundaries may still
be in the area. Any storms that develop during the heat of the day
will keep going until shortly after sunset before dissipating.
.Sunday into Wednesday...
A dry pattern will prevail, with temperatures not quite as hot.
Upper level ridge of high pressure takes a bigger role for early
next week, slowly shifting back to the west. Low level temperatures
and 850 mb readings are FORECASTED to be cooler by a few degrees, so
forecast highs at or hopefully just below the 100 degree mark. With
the ridge in place overhead and without a boundary to aid, getting
any thunderstorms to develop will be extremely tough. Will opt to
keep the forecast dry.
.Wednesday Night into Friday...
Storms will be possible again across the Big Country.
By late Wednesday, the upper level ridge will have shifted far
enough to the west to put West Central Texas into northwest flow.
This is typically a wetter pattern, as storms develop across the
Panhandle during the afternoon and move southeast into the area
during the overnight hours. Best chances look to be across the Big
Country and Heartland with the chances decreasing to the southwest.
Have inserted pops for the northeast portions of the area for now,
and leave the remainder of the area dry. But if the northwest flow
sets up as the models suggest, may have to expand the rainfall
coverage as we get into next week.
Otherwise, northwest flow is usually a little cooler as well. This
is shown in the model guidance, showing highs near climatology
normals in the mid to upper 90s.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 71 96 76 96 75 / 20 20 20 10 10
SAN ANGELO 71 99 74 97 74 / 20 20 20 10 10
JUNCTION 72 100 75 97 75 / 10 20 20 10 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
LYONS
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
406 AM EDT SAT AUG 10 2013
.SYNOPSIS...
UNSETTLED PATTERN TO CONTINUE THROUGH THE WEEKEND AS FRONT STAYS
SITUATED ACROSS THE MID ATLANTIC INTO THE MID MISSISSIPPI VALLEY.
THE FRONT WEAKENS MONDAY WITH ANOTHER FRONT SHIFTING ACROSS OUR
REGION TUESDAY. HIGH PRESSURE WILL BUILD ACROSS TO OUR NORTH MID
TO LATE NEXT WEEK BUT ENOUGH MOISTURE SITUATED ACROSS THE
SOUTHEAST WILL KEEP THE THREAT OF SHOWERS AND STORMS AROUND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 330 AM EDT SATURDAY...
UPPER TROUGH ACROSS THE GREAT LAKES AND MID MS VALLEY EXPECTED TO
TRACK EAST WITH MID LEVEL SHORTWAVES MOVING ACROSS WHILE A FRONT
SLOWLY SAGS SOUTHWARD INTO OUR AREA BY SUNDAY. FOR THIS MORNING WE
ARE SEEING SOME HEAVY RAIN SHOWERS/EMBEDDED THUNDER ACROSS THE FAR
SW VA CORRIDOR INTO PORTIONS OF NW NC. THIS IN ASSOCIATION WITH SFC
THETA-E CONVERGENCE ALONG WITH PREFRONTAL TROUGH. THE LATEST RAP/RUC
SHOWING THAT ACTIVITY SWINGS EAST THROUGH DAWN INTO THE PIEDMONT
ALTHOUGH SOME WEAKENING IN THE NEW RIVER VALLEY APPEARS TO LIMIT
WHAT THE RAP SHOWS. FURTHER UPSTREAM CONVECTION ACROSS KY/WV SHOULD
SETTLE TOWARD THE SOUTHEAST WV AREA BY DAWN AS WELL.
THE FORECAST AND MODELS THE LAST FEW DAYS ADVERTISED HIGH POPS WHICH
HAS NOT WORKED OUT AT TIMES BUT WITH IMPROVING LOW LVL CONVERGENCE
AND PROXIMITY OF UPPER SHORTWAVE AM HESITANT TO KEEP POPS LOW
TODAY. I LEANED TOWARD THE RAP THIS MORNING BUT TRANSITIONED
TOWARD THE GFS THIS AFTERNOON BLENDED WITH THE PREVIOUS FORECAST.
AM THINKING THE CORRIDOR ALONG I-64 EAST INTO THE SHENANDOAH
VALLEY WILL BE ACTIVE LATE THIS MORNING INTO EARLY AFTERNOON WITH
DENSITY OF STORMS SHIFTING CONVECTION WITH OUTFLOW SOUTHEAST INTO
THE FOOTHILLS AND PIEDMONT THIS AFTERNOON. SO FOR NOW WILL HAVE
INCREASING POPS IN THE NORTH GOING TOWARD LIKELY BY MIDDAY THEN
SHIFTING HIGHER POPS SWD THRU THE AFTERNOON. NOT GOING TO PLAY
WITH 30 VS 50-60 POPS AS AIRMASS SOUPY ENOUGH AND PLENTY OF LIFT
WITH SOME UPPER SUPPORT THE HIGHER POPS AREA WIDE.
AGAIN...THINNING OUT OF CLOUDS SHOULD ALLOW SOME SUN TO HEAT
THINGS UP ALTHOUGH JUST GOING TO BE ENOUGH CLOUD COVER ALL DAY TO
PREVENT THE TEMPS FROM WARMING TOO HIGH UNLIKE WHAT HAPPENED
FRIDAY. WENT MORE TOWARD MET MOS EAST WHICH HAS NEAR 90 WHICH IS
BETWEEN THE COOLER ECMWF AND WARMER MAV. WITH CONVECTION AND
CLOUDS MORE PREVALENT OVER THE NORTHWEST WENT THE COOLER
MET...WITH UPPER 70S TO LOWER 80S.
THOUGH HEAVY RAIN THREAT REMAINS...THE ISOLATED FLASH FLOOD THREAT
REMAINS THAT A WATCH IS NOT NEEDED YET...BUT WILL HAVE TO SEE HOW
STORMS LINE UP THIS AFTERNOON TO SEE IF WE NEED ONE. THERE IS ALSO A
SMALL RISK OF SVR STORMS WITH THE SRN BELT OF WESTERLIES ALLOWING
FOR SOME WIND THREAT.
SHOULD SEE SOME COVERAGE ENTERING TONIGHT AS MODELS KEEP SHORTWAVE
ENERGY MOVING FROM WV/KY INTO NRN VA. MODELS ARE SHOWING MORE
AGREEMENT IN HAVING BEST CHANCE WEST AND AND NORTH...ALTHOUGH SOME
SHIFT IT SOUTH INTO THE NC/VA BORDER AREA AS WEAK LOW MOVES ACROSS.
AT THIS TIME HAVE LIKELY POPS IN THE EARLY EVENING TAPERING TO 40-50
BY MIDNIGHT...WITH NO FOCUSED AREA FOR HIGHER OR LOWER POPS...AS
LOSS OF HEATING EXPECTED TO RESULT IN MORE SCATTERED COVERAGE.
STILL MUGGY WITH DRIER AIR WELL NORTH ACROSS WRN PA/NY INTO THE
GREAT LAKES STATES. LOWS WILL RANGE FROM THE MID TO UPPER 60S ACROSS
THE WEST TO AROUND 70 AT ROANOKE AND POINTS EAST.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
AS OF 320 AM EDT SATURDAY...
THE AREA WILL CONTINUE WITHIN A PROGRESSIVE REGIME WITH DISTINCT
BOUTS OF HEAVY SHOWER AND THUNDERSTORM CHANCES. THE FIRST OF THESE
WILL BE DURING THE DAY SUNDAY WHEN A COLD FRONT PASSES THROUGH THE
REGION. MOST OF THE ACTIVITY WILL HEAD SOUTH OF THE AREA BY SUNDAY
EVENING. SURFACE HIGH PRESSURE BUILDS IN BEHIND THE FRONT BRIEFLY BY
MONDAY MORNING. HOWEVER...THE AXIS OF THIS HIGH/RIDGE WILL SHIFT
EAST OF THE AREA BY MONDAY MORNING...AND THUS ALLOW FOR SOUTHEAST
LOW LEVEL FLOW TO BRING LINGERING MOISTURE BACK INTO THE SOUTHWEST
PARTS OF THE FORECAST AREA. REGIONS ALONG THE CREST OF THE BLUE
RIDGE FROM ROUGHLY FLOYD VA SOUTHWEST INTO THE NORTHERN MOUNTAINS OF
NC WILL HAVE THE GREATEST POTENTIAL FOR SHOWERS AND A FEW
THUNDERSTORMS ON MONDAY.
BY MONDAY EVENING...THERE WILL BE A DECREASE IN COVERAGE OF THE
PRECIPITATION WILL THE LOSS OF DAYTIME HEATING. HOWEVER...OUR NEXT
APPROACHING COLD FRONT WILL START TO ALLOW FOR A RETURN OF ISOLATED
TO SCATTERED SHOWERS ACROSS THE FAR WESTERN PARTS OF THE REGION BY
SUNRISE TUESDAY. DURING THE DAY TUESDAY THIS FRONT WILL CROSS THE
AREA WITH A GOOD COVERAGE OF SHOWERS AND STORMS. SHOWERS ARE LIKELY
WITH SCATTERED THUNDERSTORMS ALONG AND EAST OF THE CREST OF THE BLUE
RIDGE BY TUESDAY AFTERNOON. TUESDAY NIGHT THERE WILL BE A GRADUAL
DECREASE IN COVERAGE ACROSS THE AREA.
TEMPERATURES THROUGH THE PERIOD WILL EXPERIENCE LITTLE VARIATION
SUNDAY THROUGH TUESDAY. IT WILL NOT BE UNTIL TUESDAY NIGHT HEADING
INTO EARLY WEDNESDAY THAT A CHANGE TOWARD A SLIGHTLY DRIER...AND
THUS COOLER...AIRMASS TAKES PLACE.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 130 PM EDT FRIDAY...
LITTLE CHANGE IN THE LONG WAVE 500 MB PATTERN THROUGHOUT THIS TIME
PERIOD... WITH A RIDGE OVER THE WESTERN UNITED STATES AND TROUGHING
OVER THE EAST. MODELS NOT SHOWING GOOD TRENDS ON HOW AMPLIFIED
EASTERN TROF WILL BE.
MAIN SHORT WAVE ENERGY STAYS NORTH OF THE FORECAST AREA...BUT
WEAKER SHORT WAVES AROUND THE SOUTHERN EDGE OF THE TROF...ALONG
WITH LOW LEVEL CONVERGENCE ALONG ANY BOUNDARIES WILL PROVIDE
ENOUGH LIFT FOR THE RELATIVELY WET PATTERN TO CONTINUE.
WILL HAVE HIGHEST PROBABILITY OF PRECIPITATION IN THE AFTERNOON
AND EVENING ON THURSDAY AND FRIDAY WHEN SURFACE HIGH PRESSURE
MOVES OFFSHORE AND RETURN FLOW AROUND THE HIGH BRINGS MOISTURE
BACK INTO THE CENTRAL AND SOUTHERN APPALACHIANS.
TEMPERATURES BEHIND THE FRONT ON TUESDAY NIGHT THROUGH WEDNESDAY
NIGHT WILL BE BELOW NORMAL...BUT HOW COOL THEY GET WILL DEPEND ON
THE AMPLITUDE OF THE TROF AND HOW FAR 850 MB FRONT ADVANCES SOUTH OF
THE FORECAST AREA.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
AS OF 145 AM EDT SATURDAY...
SHOWERS WILL BE AFFECTING OR AT LEAST BE IN THE VICINITY OF THE
ROA/BCB/BLF/LWB TAF SITES THIS MORNING WITH CIGS/VSBYS SHIFTING
FROM VFR TO OCCASIONAL IFR WITH FOG.
FURTHER EAST WITH LESS STRATOCU WILL SEE LYH/DAN GET TO IFR VSBYS
AND/OR POSSIBLY CIGS AS WELL IN THE 09-12Z TIME FRAME.
AS WE HEAD INTO THE MORNING THE MODELS SHOWING GOOD THREAT OF
SHOWERS AND MOVING INTO MIDDAY/AFTERNOON THUNDERSTORMS. PROXIMITY
OF FRONT AND UPPER DISTURBANCE LEADS TO MODERATE CONFIDENCE THAT
ALL SITES GET SOME SHOWERS WITH THUNDER IN VICINITY. STILL TOO
EARLY TO PINPOINT AND ADD THUNDER TO PREDOMINANT WX GROUP BUT
BELIEVE THIS WILL CHANGE AS WE HEAD CLOSER TO MIDDAY. STILL LOOKS
LIKE OVERALL CIGS/VSBYS WILL BE VFR OUTSIDE OF CONVECTION.
TONIGHT...THE MODELS KEEP THE THREAT OF SHOWERS AROUND OVER THE
SOUTHERN HALF OF THE CWA FROM BLF-BCB-DAN SOUTH. WILL MAINTAIN
SOME VCSH AT LEAST INTO THE PIEDMONT AND BCB...BUT DRY IT OUT
ROA/BLF/LWB. WITH DEFINITE SHIFT SOUTH...THINK FOG WILL FORM IN
THE CLEARING AREAS NORTH SO OVERALL BY 06Z LWB/BLF SHOULD DROP TO
3SM.
EXTENDED DISCUSSION...THE FRONT SHIFTS SLOWLY SOUTHEAST THRU THE
WEEKEND AND KEEPS THE THREAT OF SHOWERS/STORMS AROUND. THE FRONT
MAY SLIP SOUTH OF THE AREA BY MONDAY...BUT RETURN NORTH AS A WARM
FRONT BY TUESDAY AS ANOTHER FRONT/TROUGH APPROACH FROM THE NW.
POTENTIAL FOR SHRA/TSRA ANY DAY AT DAN...POSSIBLY A BREAK
LWB/BLF/BCB MON...BUT RETURNING BY TUE TO ALL AREAS.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/WP
NEAR TERM...WP
SHORT TERM...DS
LONG TERM...AMS
AVIATION...WP
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
936 AM EDT SAT AUG 10 2013
.SYNOPSIS...
A FRONT JUST SOUTH OF THE REGION THIS MORNING WILL MOVE LITTLE OVER
THE NEXT FEW DAYS. A FEW WEAK AREAS OF LOW PRESSURE WILL RIDE ALONG
THE FRONT SUNDAY THROUGH TUESDAY. A COLD FRONT WILL CROSS THE AREA
LATER TUESDAY. HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT AND
REMAIN INTO LATE NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WITH THIS ESTF UPDATE, WE ARE GOING TO ADD A CHANCE OF SPRINKLES
SOUTH IN LINE CLOSEST WITH LATEST HRRR AND COSPA AS THEY ARE
FOLLOWING THE RADAR REFLECTIVITIES WELL. AS TO WHERE PCPN IS
REACHING THE GROUND, AOO FIRST NORTH OF MASON DIXON STATION TO
OBSERVE IT. MEASURABLE RAIN IS AS FAR EAST AS EASTERN WEST
VIRGINIA. THIS IS FARTHER EAST THAN THE LATEST RAP. THE IAD
SOUNDING IS DRY BLO 600MB AND WAL IS MOISTER BUT THAT AIR MASS IS
HEADING OUT TO SEA. IAD IN PARTICULAR CORROBORATES THE 06Z GFS
IDEA THAT OUR CWA WILL NOT BEING CONVECTIVELY ABLE TODAY. SO THE
QUESTION THEN BECOMES HOW MUCH OF THIS PCPN REACHES THE GROUND
FROM THE MID LEVEL CLOUD DECK. WE WILL FOLLOW IT THE REST OF THIS
MORNING, BUT FOR NOW FIGURE THERE WILL BE SOME "DROPS ON THE
WINDSHIELD SOUTH" AND NOT EXPECTING MORE THAN THAT. GIVEN THE
THICKER CLOUD COVER SOUTH, WE EDGED THE MAX TEMPS LOWER. OUR MAX
TEMPS ACROSS OUR CWA ARE FAIRLY UNIFORM OUTSIDE OF THE HIGHER
TERRAIN. WAL AND IAD FULL SUN SUPPORT MID 90S, BUT THE AIR MASS IS
CHILLING AND THE CLOUDS SHOULD PUT A FURTHER DAMPER ON MAX TEMPS.
THE ECHOES ARE ASSOCIATED WITH THE FIRST SHORT WAVE, THE SECOND
SHORT WAVE FARTHER WEST IN THE OHIO VALLEY IS NOT GENERATING ANY,
SO WE DID CUT OFF OUR SPRINKLE CHANCES EARLY IN THE AFTERNOON WITH
THE FIRST SHORT WAVE.
A CDFNT CLEARED THE REGION AND WILL STALL TO THE SOUTH. HIGH
PRESSURE WILL BUILD IN BEHIND THE FRONT. DRIER AIR WILL MAKE ITS
WAY IN BY AFTN AND DEW POINTS WILL DROP FROM WHERE THEY CURRENTLY
HAVE BEEN, THROUGH THE 60S AND WILL END UP AROUND 60 IN MANY
LOCATIONS BY EVENING, WITH LOWER 60S ACROSS THE S CLOSER TO THE
FRONT. THIS WILL MAKE TODAY A MUCH MORE COMFORTABLE DAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
NOT MUCH DIFFERENT TONIGHT. A GENLY DRY NIGHT WITH HIGH PRESSURE IN
CONTROL. AGAIN, A SHOWER CAN NOT BE RULED OUT OVER THE LWR
DELMARVA, BUT IT WILL BE MUCH MORE COMFORTABLE.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
A RATHER AMPLIFIED UPPER PATTERN FOR SUMMER CONTINUES WITH A DEEP
LOW PRESSURE SYSTEM ACROSS CANADA AND HIGH PRESSURE BANKED ACROSS
THE SOUTH. THE FRONT THE AFFECTED THE AREA FRIDAY WILL REMAIN TO THE
SOUTH AND A WAVE OF LOW PRESSURE WILL DEVELOP ALONG IT AND MOVE OFF
THE EAST COAST LATER SUNDAY INTO EARLY MONDAY. THIS WILL LEAD TO
SOME SLGT CHC OR LOW CHC POPS ACROSS SRN NJ AND THE DELMARVA FOR SUN
INTO SUN NIGHT. A WEAK S/W MOVING THRU MONDAY WILL LEAD TO A
CONTINUATION OF SLGT CHC POPS FOR THAT PERIOD. TEMPERATURES FOR THE
SUN-TUE PERIOD WILL MOSTLY BE NEAR NORMAL WITH HIGHS IN THE LOW TO
MID 80S AND LOWS MOSTLY IN THE 60S.
HIGH PRESSURE WILL BUILD OUT OF CANADA AND CAUSE A COLD FRONT TO
STRENGTHEN AND PUSH THROUGH THE AREA TUESDAY. THIS WILL PROLONG THE
CHCS FOR SHOWERS/SCT TSTMS FOR TUE AND INTO EARLY WED (SOUTH/EAST).
AS THIS HIGH BUILDS IN WED-FRI...A PERIOD OF DRY WEATHER AND BELOW
NORMAL TEMPERATURES IS EXPECTED. HIGHS FOR WED-FRI WILL BE MOSTLY IN
THE 70S ACROSS THE AREA WITH OVERNIGHT LOWS MID 50S TO LOW 60S.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
VFR CONDS ARE EXPECTED FOR THE TAF PD. DRIER AIR WILL BE MOVG IN
BEHIND A CFP. A GENL W TO NW FLOW IS EXPECTED WITH WIND 10 KTS OR
LESS DURG THE DAY AND DROPPING TO 5 KTS OR LESS AFTER SUNSET.
OUTLOOK...
SUN THRU MON NIGHT...MOSTLY VFR WITH SCT SHOWERS/TSTMS.
TUE AND TUE NIGHT...MOSTLY VFR BUT RESTRICTIONS POSSIBLE IN
SHOWERS/TSTMS.
WED...MOSTLY VFR.
&&
.MARINE...
RELATIVELY QUIET CONDS ON THE AREA WATERS WITH W TO NW FLOW AROUND
10 KTS AND SEAS DECREASING. SEAS WILL END UP IN THE 2 TO 3 FT RANGE
AFTER BEING AS HIGH AS 4 FT THIS MRNG. A CDFNT WILL CROSS THE AREA
WATERS LATER THIS MRNG AND THE WIND WILL SHIFT TO W THEN NW. NO
HEADLINES ARE ANTICIPATED THRU THE NR AND SHORT TERM PDS.
OUTLOOK...
SUB-SCA CONDITIONS ARE EXPECTED THROUGH THE LONGER TERM PART OF
THE FCST. A FEW SHOWERS/TSTMS ARE POSSIBLE SUN-TUE NIGHT.
&&
.CLIMATE...
A PHLRERGED WAS ISSUED EARLIER FOR A RECORD PCPN AT GEORGETOWN,
DE. MOUNT POCONO, PA ALSO SET A PCPN RECORD FRIDAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...O`HARA
NEAR TERM...GIGI/NIERENBERG
SHORT TERM...NIERENBERG
LONG TERM...O`HARA
AVIATION...NIERENBERG/O`HARA
MARINE...NIERENBERG/O`HARA
CLIMATE...O`O`HARA
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1055 AM CDT SAT AUG 10 2013
.DISCUSSION...
341 AM CDT
MAIN FORECAST CONCERN IS SHRA/TSRA CHANCES SUNDAY THROUGH MONDAY
EVENING. EARLY MORNING W/V IMAGERY SHOWS BROAD TROUGHING FROM
EASTERN INTO CENTRAL CANADA AND THE NORTHERN LAKES WITH RIDGING
OVER THE WESTERN CONUS AND SEVERAL WAVES CRESTING THE RIDGE OVER
THE NORTHERN ROCKIES THAT WILL PLAY A ROLE IN OUR SENSIBLE WEATHER
ON SUNDAY AND SUNDAY NIGHT AS THEY TRAVERSE DISTURBED WEST-
NORTHWEST FLOW ALOFT. AT THE SURFACE...HIGH PRESSURE WILL CENTER
OVER THE REGION TODAY...BEFORE SLOWLY SLIDING EAST SUNDAY. A COLD
FRONT WILL MOVE THROUGH THE AREA ON MONDAY.
COOLER AIR MASS WILL FILTER INTO AREA TODAY...NOTED WITH +10 AND +11
RESPECTIVELY AT 850 MB AT KMPX AND KGRB ON THE 00Z RAOBS. THE BACK
EDGE OF CIRRUS SHIELD OVER THE AREA WILL CLEAR OFF TO THE EAST OF
BY DAYBREAK OR SO...YIELDING EARLY MORNING CLEAR SKIES...BUT
GUIDANCE SHOWS MOISTURE FROM H9-H8 SEEPING IN FROM NORTH DURING
DAY...WHICH SHOULD ALLOW FOR SCATTERED TO POSSIBLY BROKEN CUMULUS BY
THE AFTERNOON AS LOW LEVEL LAPSE RATES STEEPEN. PROGGED H8 AND H9
TEMPS SUPPORTS HIGHS IN THE UPPER 70S TO POSSIBLY AROUND 80 NORTH OF
I-80 AND LOWER 80S SOUTH...WITH A FEW MID 80S READINGS. THE
EXCEPTION WILL BE THE LAKEFRONT WITH SYNOPTIC ONSHORE FLOW AND HIGHS
ONLY IN THE LOWER AND MID 70S. ALL IN ALL...IT WILL BE A SPECTACULAR
START TO THE WEEKEND. HIGH PRESSURE OVERHEAD TONIGHT AND MAINLY
CLEAR SKIES WILL RESULT IN COOL CONDITIONS IN THE LOWER AND MID 50S
OUTSIDE OF THE CHICAGO HEAT ISLAND.
THE INITIAL LEAD WAVE CURRENTLY OVER WYOMING LOOKS TO BE APPROACHING
THE REGION BUT LIKELY FOCUS NEAR OR NORTH OF THE WISCONSIN BORDER.
BY EARLY SUNDAY...A CLUSTER OF SHRA/TSRA COULD TRAVERSE THE UPPER
MISSISSIPPI VALLEY BUT IT SHOULD WEAKEN FARTHER EAST DUE TO THE
INFLUENCE OF THE HIGH PRESSURE RIDGE...LIMITED ELEVATED INSTABILITY
AND VERY WEAK LAPSE RATES ALOFT. DESPITE SOME CONSENSUS IN THE
GUIDANCE ON TRACKING THIS FEATURE TOWARD SOUTHERN WISCONSIN...HAVE
GENERALLY MAINTAINED CHANCE POPS ALONG THE BORDER. THE EXTENT OF
CLOUD COVER WITH THIS WAVE COULD LIMIT TEMPERATURES A BIT MORE THAN
CURRENTLY DEPICTED TO THE NORTH...BUT TO THE SOUTH...WHERE LESS
CLOUD COVER IS ANTICIPATED....850/925 TEMPS WILL SUPPORT HIGHS
APPROACHING THE MID 80S. GIVEN THE FACTORS THAT WILL LIKELY LEAD TO
WEAKENING OF THE PRECIP SHIELD ASSOCIATED WITH THE MID-LEVEL
WAVE...IT STILL REMAINS POSSIBLE THAT MOST OF THE AREA COULD HAVE A
DRY SUNDAY.
STRENGTHENING LOW LEVEL FLOW WILL RESULT IN DECENT MOISTURE
TRANSPORT AND CONVERGENCE FOCUSED INTO THE NORTHERN THIRD OF CWA
SUNDAY NIGHT WITH ANOTHER MID-LEVEL FEATURE WELL AHEAD OF SURFACE
COLD FRONT THAT WILL BE APPROACHING SLOWLY FROM THE NORTHWEST. EXACT
TRACK OF MIDLEVEL WAVE AND STRENGTH OF 850-925 FLOW WILL NEED TO BE
RESOLVED...BUT HAVE BUMPED UP POPS TO HIGH CHANCE RANGE ALONG THE
WISCONSIN BORDER...TAPERING TO A DRY FORECAST IN THE FAR SOUTHERN
FORECAST SOUNDINGS SHOWING SOME ELEVATED INSTABILITY AND WARM
ADVECTION PATTERN MEANS THERE WILL LIKELY BE AT LEAST EMBEDDED
THUNDER. CLOUD COVER AND WARM ADVECTION WILL RESULT IN MILDER LOW
TEMPS.
THE CONVECTIVE EVOLUTION ON SUNDAY NIGHT INTO EARLY MONDAY WILL
DICTATE TO A LARGE EXTENT WHAT HAPPENS WITH CONVECTIVE CHANCES ON
MONDAY AHEAD OF A COLD FRONT. FAVOR A SLOWER FRONTAL PASSAGE DURING
THE AFTERNOON...BUT NOT QUITE AS SLOW AS LATEST NAM. ASSUMING CLOUD
COVER DOES NOT HINDER WARMING TOO MUCH...H85 TEMPS AROUND +15 WILL
YIELD HIGHS IN THE LOWER 80S NORTH AND MID 80S SOUTH...WITH
DEWPOINTS RETURNING TO THE MID TO UPPER 60S. THIS COULD YIELD ~1500
J/KG OF CAPE PER FORECAST SOUNDINGS...WITH DECENT CONVERGENCE FROM
THE SURFACE TO 850 MB FAVORING AT LEAST SCATTERED COVERAGE OF
THUNDERSTORMS...BUT DID NOT GO HIGHER THAN MID CHANCE POPS DUE TO
UNCERTAINTY OVER CONVECTIVE EVOLUTION. IF ENOUGH INSTABILITY
DEVELOPS...WILL NEED TO WATCH FOR A SEVERE THREAT PRIMARILY IN THE
FORM OF DAMAGING WINDS...AS NORTHWESTERLY FLOW ALOFT WILL INCREASE
TO 40 KT DURING THE DAY AND STEEP LOW LEVEL LAPSE RATES WILL DEVELOP
AS WELL. HIGH FREEZING LEVELS AND MEAGER LAPSE RATES ABOVE 600 MB
WOULD LIKELY LIMIT THE HAIL THREAT.
ANY REMAINING SHRA/TSRA SHOULD CLEAR THE SOUTHERN CWA DURING THE
EVENING...WITH HIGH PRESSURE BUILDING FROM UPPER MIDWEST BEHIND COLD
FRONT. COOL NORTHERLY FLOW FROM THE SURFACE UP TO THE MID LEVELS
THANKS TO UPPER TROUGHING OVER EASTERN CANADA WILL SET UP A BELOW
NORMAL...BUT PLEASANT TUESDAY THROUGH FRIDAY PERIOD. AFTER HIGHS
LIKELY ONLY IN THE MID 70S AWAY FROM THE LAKE TUES AND
WEDS...READINGS WILL WARM SOME BY FRIDAY AS HEIGHTS BEGIN TO RISE
AND THERMAL PROFILES SLOWLY WARM. THE LAKEFRONT WILL BE KEPT COOLER
EACH DAY BY PERSISTENT ONSHORE FLOW.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* NONE IN NEAR TERM.
RATZER
//DISCUSSION...UPDATED 12Z...
HIGH PRESSURE IS BUILDING IN FROM THE NORTHWEST THIS MORNING
FOLLOWING THE PASSAGE OF A COOL FRONTAL BOUNDARY LAST EVENING.
LIGHT NNW WINDS HAVE BEEN REPORTED AT THE TERMINALS WITH
ORD/MDW/GYY EXPECTED TO TURN MORE NORTHEASTERLY THIS MORNING
THANKS TO A COMBINATION OF THE EVOLVING PRESSURE GRADIENT AND
INFLUENCE OF LAKE MICHIGAN. SPEEDS SHOULD GENERALLY BE AT OR BELOW
10 KT THROUGH THE DAY. SCATTERED TO PERHAPS PERIODICALLY BKN VFR
CLOUDS IN THE 4000-6000 FT RANGE ARE EXPECTED TO DEVELOP LATER
THIS MORNING WITH A FEW PATCHES OF MID CLOUDS POSSIBLY WORKING IN
FROM THE NORTHWEST AS WELL...BUT THE BULK OF THIS LOOKS TO REMAIN
TO THE NORTH. WINDS WILL DROP OFF TO LIGHT AND VARIABLE OR CALM
TONIGHT WITH THE HIGH MOVING OVERHEAD. THE HIGH WILL BE IN PLACE
SUNDAY AS WELL BUT START TO SHIFT TO THE EAST LATER IN THE DAY.
THIS WILL KEEP LIGHT AND VARIABLE WINDS IN PLACE FOR MUCH OF THE
DAY BUT THERE SHOULD BE A TENDENCY FOR A PREVAILING WEST TO
SOUTHWEST WIND DIRECTION. MID CLOUD WILL LIKELY INCREASE WITH SOME
CHANCE FOR SHOWERS BUT THIS LOOKS TO PRIMARILY OCCUR NORTH OF THE
TERMINALS SO WILL CONTINUE WITH A DRY FORECAST FOR NOW.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE ALL ELEMENTS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...CHANCE SHRA/TSRA.
MONDAY...CHANCE SHRA/TSRA. MVFR POSSIBLE.
TUESDAY THROUGH FRIDAY...DRY/VFR.
MDB
&&
.MARINE...
252 AM CDT
DEEPENING LOW PRESSURE IS MOVING EASTWARD ACROSS EASTERN QUEBEC THIS
MORNING. ONE AREA OF HIGH PRESSURE IS SPREAD ACROSS THE OHIO RIVER
VALLEY AND THE SOUTHEAST U.S. WHILE ANOTHER AREA OF HIGH PRESSURE IS
SPREAD FROM THE CANADIAN PRAIRIES TO THE CENTRAL PLAINS. THIS
NORTHERN HIGH WILL MOVE SOUTHEASTWARD AND ACROSS CENTRAL ILLINOIS
TONIGHT. A TROUGH OF LOW PRESSURE WILL THEN MOVE ACROSS THE AREA
EARLY MONDAY WITH STRONG CANADIAN HIGH PRESSURE BUILDING IN BEHIND
IT INTO TUESDAY. AS A RESULT...SOUTHERLY WINDS AHEAD OF THE FRONT
MONDAY WILL TURN NORTHERLY LATER MONDAY INTO TUESDAY AS LOW PRESSURE
BEGINS TO DEEPEN ACROSS NORTHERN NEW ENGLAND. EXPECT THAT WINDS WILL
COME UP TO AROUND 20 KT MONDAY NIGHT AND TUESDAY AS THE PRESSURE
GRADIENT TIGHTENS AND A PUSH OF COOLER AIR SPREADS IN. THIS WILL
KICK WAVES UP TO NEAR SMALL CRAFT ADVISORY CRITERIA BEFORE SUBSIDING
TUESDAY NIGHT OR WEDNESDAY MORNING. HIGH PRESSURE WILL THEN BE OVER
THE AREA WEDNESDAY THROUGH THE REST OF NEXT WEEK.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
[top]
Area Forecast Discussion
National Weather Service Lincoln IL
1039 AM CDT Sat Aug 10 2013
.DISCUSSION...
ISSUED 1035 AM CDT Sat Aug 10 2013
Mild weather in store for central Illinois through the weekend as
high pressure builds into the Midwest from the Plains. Warm and
sunny conditions expected with a few fair weather clouds possible
into the late morning and early afternoon hours. Going forecast
looks good. Have adjusted the high temperatures up a couple
degrees in the northern CWA to reflect a quicker warm up...as well
as a tweak to the hourly temperature forecast for the remainder of
the day. Adjustments are relatively slight and no updates to the
zone forecast are anticipated.
HJS
&&
.AVIATION...
ISSUED 609 AM CDT Sat Aug 10 2013
VFR conditions will prevail over the next 24 hours. May see a bit
of light fog near KCMI over the next hour as skies clear, and have
seen a slow decrease in visibilities since 08Z but any MVFR
conditions will be brief. Not much in the way of cloud cover
expected now that the extensive cloudiness has largely exited the
TAF sites, with subsidence expected to keep any diurnal
development to a minimum.
Geelhart
&&
.PREV DISCUSSION...
ISSUED 240 AM CDT Sat Aug 10 2013
SHORT TERM...Today through Monday
Weak secondary cold front will continue to drop southward and
dissipate across central Illinois today, while main synoptic
boundary remains stalled from the Mid-Atlantic states W/SW into
the Southern Plains. Periods of showers and thunderstorms will
accompany the primary front, but will stay well south of the
KILX CWA. High-res HRRR hints at a few showers potentially
developing ahead of a weak short-wave across northern Indiana this
afternoon, but these would likely remain outside of central
Illinois as well. End result will be a partly to mostly sunny day
with high temperatures in the lower 80s.
High pressure will build southward into the region tonight, providing
cool/dry weather with lows dropping into the 50s. With high pressure
overhead, another pleasant summer day is in store for Sunday with
highs reaching the lower to middle 80s. Once the high begins to
slide off to the east, a light southerly return flow will allow a
warmer/more humid air mass to trickle back into the area Sunday
night into Monday. Forecast soundings indicate precipitable water
values climbing back over 1.50 inches while surface dewpoints
reach the 70-degree mark by Monday afternoon. Meanwhile...another
deep upper low will rotate southward from Hudson Bay, pushing a cold
front into Illinois. This front will interact with the increasingly
moist air mass to produce scattered showers and thunderstorms,
particularly during the afternoon and evening. Due to only modest
instability with CAPE values around 1500J/kg and best upper
support remaining further north across the Great Lakes, am not
expecting widespread convection. Will therefore maintain just
chance pops Monday into Monday night.
LONG TERM...Tuesday through Friday
Frontal boundary sags southward early next week, with model consensus
taking it south of the Ohio River by Tuesday morning. Will hold on
to just a slight chance POP across the far SE CWA into Tuesday in
case front slows. Otherwise, another cool/dry Canadian air mass
will settle southward into the region behind the departing front
for the remainder of next week. With upper flow becoming
prominently northwesterly, any potential MCS activity will likely
be shunted well W/SW of Illinois, leading to a dry forecast
through Friday. Temps next week will remain below normal, with
afternoon highs generally in the upper 70s/lower 80s and overnight
lows in the upper 50s/lower 60s.
Barnes
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
637 AM CDT SAT AUG 10 2013
.DISCUSSION...
341 AM CDT
MAIN FORECAST CONCERN IS SHRA/TSRA CHANCES SUNDAY THROUGH MONDAY
EVENING. EARLY MORNING W/V IMAGERY SHOWS BROAD TROUGHING FROM
EASTERN INTO CENTRAL CANADA AND THE NORTHERN LAKES WITH RIDGING
OVER THE WESTERN CONUS AND SEVERAL WAVES CRESTING THE RIDGE OVER
THE NORTHERN ROCKIES THAT WILL PLAY A ROLE IN OUR SENSIBLE WEATHER
ON SUNDAY AND SUNDAY NIGHT AS THEY TRAVERSE DISTURBED WEST-
NORTHWEST FLOW ALOFT. AT THE SURFACE...HIGH PRESSURE WILL CENTER
OVER THE REGION TODAY...BEFORE SLOWLY SLIDING EAST SUNDAY. A COLD
FRONT WILL MOVE THROUGH THE AREA ON MONDAY.
COOLER AIR MASS WILL FILTER INTO AREA TODAY...NOTED WITH +10 AND +11
RESPECTIVELY AT 850 MB AT KMPX AND KGRB ON THE 00Z RAOBS. THE BACK
EDGE OF CIRRUS SHIELD OVER THE AREA WILL CLEAR OFF TO THE EAST OF
BY DAYBREAK OR SO...YIELDING EARLY MORNING CLEAR SKIES...BUT
GUIDANCE SHOWS MOISTURE FROM H9-H8 SEEPING IN FROM NORTH DURING
DAY...WHICH SHOULD ALLOW FOR SCATTERED TO POSSIBLY BROKEN CUMULUS BY
THE AFTERNOON AS LOW LEVEL LAPSE RATES STEEPEN. PROGGED H8 AND H9
TEMPS SUPPORTS HIGHS IN THE UPPER 70S TO POSSIBLY AROUND 80 NORTH OF
I-80 AND LOWER 80S SOUTH...WITH A FEW MID 80S READINGS. THE
EXCEPTION WILL BE THE LAKEFRONT WITH SYNOPTIC ONSHORE FLOW AND HIGHS
ONLY IN THE LOWER AND MID 70S. ALL IN ALL...IT WILL BE A SPECTACULAR
START TO THE WEEKEND. HIGH PRESSURE OVERHEAD TONIGHT AND MAINLY
CLEAR SKIES WILL RESULT IN COOL CONDITIONS IN THE LOWER AND MID 50S
OUTSIDE OF THE CHICAGO HEAT ISLAND.
THE INITIAL LEAD WAVE CURRENTLY OVER WYOMING LOOKS TO BE APPROACHING
THE REGION BUT LIKELY FOCUS NEAR OR NORTH OF THE WISCONSIN BORDER.
BY EARLY SUNDAY...A CLUSTER OF SHRA/TSRA COULD TRAVERSE THE UPPER
MISSISSIPPI VALLEY BUT IT SHOULD WEAKEN FARTHER EAST DUE TO THE
INFLUENCE OF THE HIGH PRESSURE RIDGE...LIMITED ELEVATED INSTABILITY
AND VERY WEAK LAPSE RATES ALOFT. DESPITE SOME CONSENSUS IN THE
GUIDANCE ON TRACKING THIS FEATURE TOWARD SOUTHERN WISCONSIN...HAVE
GENERALLY MAINTAINED CHANCE POPS ALONG THE BORDER. THE EXTENT OF
CLOUD COVER WITH THIS WAVE COULD LIMIT TEMPERATURES A BIT MORE THAN
CURRENTLY DEPICTED TO THE NORTH...BUT TO THE SOUTH...WHERE LESS
CLOUD COVER IS ANTICIPATED....850/925 TEMPS WILL SUPPORT HIGHS
APPROACHING THE MID 80S. GIVEN THE FACTORS THAT WILL LIKELY LEAD TO
WEAKENING OF THE PRECIP SHIELD ASSOCIATED WITH THE MID-LEVEL
WAVE...IT STILL REMAINS POSSIBLE THAT MOST OF THE AREA COULD HAVE A
DRY SUNDAY.
STRENGTHENING LOW LEVEL FLOW WILL RESULT IN DECENT MOISTURE
TRANSPORT AND CONVERGENCE FOCUSED INTO THE NORTHERN THIRD OF CWA
SUNDAY NIGHT WITH ANOTHER MID-LEVEL FEATURE WELL AHEAD OF SURFACE
COLD FRONT THAT WILL BE APPROACHING SLOWLY FROM THE NORTHWEST. EXACT
TRACK OF MIDLEVEL WAVE AND STRENGTH OF 850-925 FLOW WILL NEED TO BE
RESOLVED...BUT HAVE BUMPED UP POPS TO HIGH CHANCE RANGE ALONG THE
WISCONSIN BORDER...TAPERING TO A DRY FORECAST IN THE FAR SOUTHERN
FORECAST SOUNDINGS SHOWING SOME ELEVATED INSTABILITY AND WARM
ADVECTION PATTERN MEANS THERE WILL LIKELY BE AT LEAST EMBEDDED
THUNDER. CLOUD COVER AND WARM ADVECTION WILL RESULT IN MILDER LOW
TEMPS.
THE CONVECTIVE EVOLUTION ON SUNDAY NIGHT INTO EARLY MONDAY WILL
DICTATE TO A LARGE EXTENT WHAT HAPPENS WITH CONVECTIVE CHANCES ON
MONDAY AHEAD OF A COLD FRONT. FAVOR A SLOWER FRONTAL PASSAGE DURING
THE AFTERNOON...BUT NOT QUITE AS SLOW AS LATEST NAM. ASSUMING CLOUD
COVER DOES NOT HINDER WARMING TOO MUCH...H85 TEMPS AROUND +15 WILL
YIELD HIGHS IN THE LOWER 80S NORTH AND MID 80S SOUTH...WITH
DEWPOINTS RETURNING TO THE MID TO UPPER 60S. THIS COULD YIELD ~1500
J/KG OF CAPE PER FORECAST SOUNDINGS...WITH DECENT CONVERGENCE FROM
THE SURFACE TO 850 MB FAVORING AT LEAST SCATTERED COVERAGE OF
THUNDERSTORMS...BUT DID NOT GO HIGHER THAN MID CHANCE POPS DUE TO
UNCERTAINTY OVER CONVECTIVE EVOLUTION. IF ENOUGH INSTABILITY
DEVELOPS...WILL NEED TO WATCH FOR A SEVERE THREAT PRIMARILY IN THE
FORM OF DAMAGING WINDS...AS NORTHWESTERLY FLOW ALOFT WILL INCREASE
TO 40 KT DURING THE DAY AND STEEP LOW LEVEL LAPSE RATES WILL DEVELOP
AS WELL. HIGH FREEZING LEVELS AND MEAGER LAPSE RATES ABOVE 600 MB
WOULD LIKELY LIMIT THE HAIL THREAT.
ANY REMAINING SHRA/TSRA SHOULD CLEAR THE SOUTHERN CWA DURING THE
EVENING...WITH HIGH PRESSURE BUILDING FROM UPPER MIDWEST BEHIND COLD
FRONT. COOL NORTHERLY FLOW FROM THE SURFACE UP TO THE MID LEVELS
THANKS TO UPPER TROUGHING OVER EASTERN CANADA WILL SET UP A BELOW
NORMAL...BUT PLEASANT TUESDAY THROUGH FRIDAY PERIOD. AFTER HIGHS
LIKELY ONLY IN THE MID 70S AWAY FROM THE LAKE TUES AND
WEDS...READINGS WILL WARM SOME BY FRIDAY AS HEIGHTS BEGIN TO RISE
AND THERMAL PROFILES SLOWLY WARM. THE LAKEFRONT WILL BE KEPT COOLER
EACH DAY BY PERSISTENT ONSHORE FLOW.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* NNW WINDS TURNING NE THIS MORNING.
MDB
//DISCUSSION...UPDATED 12Z...
HIGH PRESSURE IS BUILDING IN FROM THE NORTHWEST THIS MORNING
FOLLOWING THE PASSAGE OF A COOL FRONTAL BOUNDARY LAST EVENING.
LIGHT NNW WINDS HAVE BEEN REPORTED AT THE TERMINALS WITH
ORD/MDW/GYY EXPECTED TO TURN MORE NORTHEASTERLY THIS MORNING
THANKS TO A COMBINATION OF THE EVOLVING PRESSURE GRADIENT AND
INFLUENCE OF LAKE MICHIGAN. SPEEDS SHOULD GENERALLY BE AT OR BELOW
10 KT THROUGH THE DAY. SCATTERED TO PERHAPS PERIODICALLY BKN VFR
CLOUDS IN THE 4000-6000 FT RANGE ARE EXPECTED TO DEVELOP LATER
THIS MORNING WITH A FEW PATCHES OF MID CLOUDS POSSIBLY WORKING IN
FROM THE NORTHWEST AS WELL...BUT THE BULK OF THIS LOOKS TO REMAIN
TO THE NORTH. WINDS WILL DROP OFF TO LIGHT AND VARIABLE OR CALM
TONIGHT WITH THE HIGH MOVING OVERHEAD. THE HIGH WILL BE IN PLACE
SUNDAY AS WELL BUT START TO SHIFT TO THE EAST LATER IN THE DAY.
THIS WILL KEEP LIGHT AND VARIABLE WINDS IN PLACE FOR MUCH OF THE
DAY BUT THERE SHOULD BE A TENDENCY FOR A PREVAILING WEST TO
SOUTHWEST WIND DIRECTION. MID CLOUD WILL LIKELY INCREASE WITH SOME
CHANCE FOR SHOWERS BUT THIS LOOKS TO PRIMARILY OCCUR NORTH OF THE
TERMINALS SO WILL CONTINUE WITH A DRY FORECAST FOR NOW.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* HIGH CONFIDENCE IN WINDS TURNING NE...MEDIUM-HIGH CONFIDENCE IN
TIMING.
MDB
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...CHANCE SHRA/TSRA.
MONDAY...CHANCE SHRA/TSRA. MVFR POSSIBLE.
TUESDAY THROUGH FRIDAY...DRY/VFR.
MDB
&&
.MARINE...
252 AM CDT
DEEPENING LOW PRESSURE IS MOVING EASTWARD ACROSS EASTERN QUEBEC THIS
MORNING. ONE AREA OF HIGH PRESSURE IS SPREAD ACROSS THE OHIO RIVER
VALLEY AND THE SOUTHEAST U.S. WHILE ANOTHER AREA OF HIGH PRESSURE IS
SPREAD FROM THE CANADIAN PRAIRIES TO THE CENTRAL PLAINS. THIS
NORTHERN HIGH WILL MOVE SOUTHEASTWARD AND ACROSS CENTRAL ILLINOIS
TONIGHT. A TROUGH OF LOW PRESSURE WILL THEN MOVE ACROSS THE AREA
EARLY MONDAY WITH STRONG CANADIAN HIGH PRESSURE BUILDING IN BEHIND
IT INTO TUESDAY. AS A RESULT...SOUTHERLY WINDS AHEAD OF THE FRONT
MONDAY WILL TURN NORTHERLY LATER MONDAY INTO TUESDAY AS LOW PRESSURE
BEGINS TO DEEPEN ACROSS NORTHERN NEW ENGLAND. EXPECT THAT WINDS WILL
COME UP TO AROUND 20 KT MONDAY NIGHT AND TUESDAY AS THE PRESSURE
GRADIENT TIGHTENS AND A PUSH OF COOLER AIR SPREADS IN. THIS WILL
KICK WAVES UP TO NEAR SMALL CRAFT ADVISORY CRITERIA BEFORE SUBSIDING
TUESDAY NIGHT OR WEDNESDAY MORNING. HIGH PRESSURE WILL THEN BE OVER
THE AREA WEDNESDAY THROUGH THE REST OF NEXT WEEK.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Lincoln IL
610 AM CDT Sat Aug 10 2013
.DISCUSSION...
ISSUED 240 AM CDT Sat Aug 10 2013
SHORT TERM...Today through Monday
Weak secondary cold front will continue to drop southward and
dissipate across central Illinois today, while main synoptic
boundary remains stalled from the Mid-Atlantic states W/SW into
the Southern Plains. Periods of showers and thunderstorms will
accompany the primary front, but will stay well south of the
KILX CWA. High-res HRRR hints at a few showers potentially
developing ahead of a weak short-wave across northern Indiana this
afternoon, but these would likely remain outside of central
Illinois as well. End result will be a partly to mostly sunny day
with high temperatures in the lower 80s.
High pressure will build southward into the region tonight, providing
cool/dry weather with lows dropping into the 50s. With high pressure
overhead, another pleasant summer day is in store for Sunday with
highs reaching the lower to middle 80s. Once the high begins to
slide off to the east, a light southerly return flow will allow a
warmer/more humid air mass to trickle back into the area Sunday
night into Monday. Forecast soundings indicate precipitable water
values climbing back over 1.50 inches while surface dewpoints
reach the 70-degree mark by Monday afternoon. Meanwhile...another
deep upper low will rotate southward from Hudson Bay, pushing a cold
front into Illinois. This front will interact with the increasingly
moist air mass to produce scattered showers and thunderstorms,
particularly during the afternoon and evening. Due to only modest
instability with CAPE values around 1500J/kg and best upper
support remaining further north across the Great Lakes, am not
expecting widespread convection. Will therefore maintain just
chance pops Monday into Monday night.
LONG TERM...Tuesday through Friday
Frontal boundary sags southward early next week, with model consensus
taking it south of the Ohio River by Tuesday morning. Will hold on
to just a slight chance POP across the far SE CWA into Tuesday in
case front slows. Otherwise, another cool/dry Canadian air mass
will settle southward into the region behind the departing front
for the remainder of next week. With upper flow becoming
prominently northwesterly, any potential MCS activity will likely
be shunted well W/SW of Illinois, leading to a dry forecast
through Friday. Temps next week will remain below normal, with
afternoon highs generally in the upper 70s/lower 80s and overnight
lows in the upper 50s/lower 60s.
Barnes
&&
.AVIATION...
ISSUED 609 AM CDT Sat Aug 10 2013
VFR conditions will prevail over the next 24 hours. May see a bit
of light fog near KCMI over the next hour as skies clear, and have
seen a slow decrease in visibilities since 08Z but any MVFR
conditions will be brief. Not much in the way of cloud cover
expected now that the extensive cloudiness has largely exited the
TAF sites, with subsidence expected to keep any diurnal
development to a minimum.
Geelhart
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1022 AM EDT SAT AUG 10 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 339 AM EDT SAT AUG 10 2013
A SECONDARY COLD FRONT WILL TRAVERSE CENTRAL INDIANA
TODAY...BRINGING A SLIGHT CHANCE FOR SOME SCATTERED SHOWERS
THIS MORNING AND ISOLATED THUNDERSTORMS THIS AFTERNOON. HIGH
PRESSURE WILL RESULT IN DRY CONDITIONS FROM TONIGHT THROUGH
SUNDAY. HOWEVER...A WEAK SURFACE LOW WILL TRY TO ENTER CENTRAL
INDIANA FROM THE SOUTH ON MONDAY...FOLLOWED BY A STRONGER COLD
FRONT THAT NIGHT WHICH WILL BRING ADDITIONAL SHOWER AND
THUNDERSTORM CHANCES INTO TUESDAY MORNING.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 955 AM EDT SAT AUG 10 2013
MID AND HIGH LEVEL CLOUDS PERSISTING SO FAR THIS MORNING ACROSS
ALL BUT NORTHERN PORTIONS OF THE FORECAST AREA. A FEW LIGHT
SHOWERS CONTINUE TO GRAZE FAR SOUTHERN COUNTIES AS A WEAK WAVE
ALOFT PASSES THROUGH THE LOWER OHIO VALLEY. TEMPS WERE GENERALLY
IN THE LOWER AND MIDDLE 70S AS OF 13Z.
FORECAST IN GOOD SHAPE THIS MORNING WITH JUST MINOR CHANGES
NEEDED. WEAK SURFACE WAVE ALONG SECONDARY FRONT NOTED ACROSS
NORTHEAST INDIANA WITH THE BOUNDARY EXTENDING SOUTHWEST INTO
CENTRAL ILLINOIS. THE BOUNDARY WILL PROGRESS SLOWLY SOUTH ACROSS
THE FORECAST AREA THROUGH THE AFTERNOON AND EVENING. WHILE FORCING
ALOFT REMAINS VERY WEAK...PRESENCE OF LOW LEVEL MOISTURE AND WEAK
INSTABILITY AHEAD OF THE BOUNDARY WILL LIKELY BE ENOUGH TO
GENERATE ISOLATED CONVECTION THROUGH THE AFTERNOON AND EARLY
EVENING...ESPECIALLY OVER THE SOUTHEAST HALF OF THE FORECAST AREA.
CURRENT HRRR CAPTURES THIS IDEA WELL...HINTING AT BEST POTENTIAL
FOR CONVECTIVE DEVELOPMENT OVER EASTERN COUNTIES WHICH MAKES SENSE
WITH SLIGHTLY BETTER FORCING ALOFT TO THE EAST OVER OHIO. WILL
MAINTAIN LOW CHANCE POPS THROUGH THE AFTERNOON OVER ALL BUT THE
NORTHERN WABASH VALLEY...AND INTO THE EVENING OVER FAR SOUTHERN
COUNTIES.
BUMPED UP HIGHS IN NORTHERN COUNTIES BY A DEGREE OR TWO...
ESPECIALLY WITH A MAINLY SUNNY START BEFORE CU FIELD DEVELOPS
LATER TODAY. OTHERWISE FORECAST HIGH TEMPS LOOK REASONABLE.
ZONE AND GRID UPDATES OUT.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
ISSUED AT 339 AM EDT SAT AUG 10 2013
HIGH PRESSURE WILL BUILD INTO CENTRAL INDIANA TONIGHT...INFLUENCING
THE AREA THROUGH SUNDAY NIGHT. THE NEXT CHANCE FOR ANY MEASURABLE
PRECIP WILL BE MONDAY/MONDAY NIGHT AS A COLD FRONT ENTERS FROM THE
NORTHWEST. THIS FRONT WILL COMBINE WITH SOME MOISTURE RETROGRADING
BACK INTO THE REGION. AS A RESULT...CHANCE POPS SEEM REASONABLE AT
THIS TIME DURING THE MONDAY/MONDAY NIGHT TIME FRAME.
TEMPS...MODELS ARE SHOWING SOME INCONSISTENCY WITH REGARD TO
CHANGING WEATHER PATTERN AT END OF SHORT TERM PERIOD. WENT WITH A
BLEND FROM TONIGHT THROUGH SUNDAY NIGHT...AND THEN LEANED TOWARD
THE WARMER GFS ON MONDAY TO CAPTURE ANY WARM AIR ADVECTION WITH A
SURFACE WARM FRONT.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
ISSUED AT 339 AM EDT SAT AUG 10 2013
ENSEMBLES INDICATE A RATHER STABLE WEATHER PATTERN DURING THIS
PERIOD. SUBTROPICAL RIDGE REMAINS ALONG THE GULF COAST/SOUTHERN
PLAINS REGION...WHILE UPPER TROUGHING CONTINUES OVER THE GREAT LAKES
AND NEW ENGLAND.
ENSEMBLES SUGGEST AN UPPER DISTURBANCE WILL BE IN THE PROCESS OF
PASSING OVER THE GREAT LAKES ON TUESDAY. WILL KEEP SOME CHANCE POPS
IN THE FORECAST ON TUESDAY TO COVER THIS FEATURE.
OTHERWISE...ENSEMBLES INDICATING LITTLE THREAT FOR PRECIPITATION FOR
THE REST OF THE EXTENDED...SO WILL GO DRY AFTER TUESDAY.
&&
.AVIATION /DISCUSSION FOR THE 101500Z TAF UPDATE/...
ISSUED AT 1022 AM EDT SAT AUG 10 2013
BACK EDGE OF AC DECK IS ALMOST TO KIND. AFTER THAT MOVES THROUGH
EXPECT SCATTERED CU AND AC.
PREVIOUS DISCUSSION FOLLOWS...
SOME SPRINKLES POSSIBLE IN THE VICINITY OF THE TAF SITES THROUGH
ABOUT MID MORNING...OTHERWISE CONVECTIVE PARAMETERS SUGGEST ANY DEEP
CONVECTION WILL BE SOUTH OF THE TAF SITES TODAY.
SOME DIURNAL CLOUDS BASED AROUND 030 EXPECTED TO DEVELOP TOWARDS THE
MIDDAY HOURS.
NO VISIBILITY OR WIND ISSUES EXPECTED AT THE TAF SITES THROUGH
110000Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...RYAN
SHORT TERM...TDUD
LONG TERM....JAS
AVIATION...JAS/50
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
955 AM EDT SAT AUG 10 2013
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 339 AM EDT SAT AUG 10 2013
A SECONDARY COLD FRONT WILL TRAVERSE CENTRAL INDIANA
TODAY...BRINGING A SLIGHT CHANCE FOR SOME SCATTERED SHOWERS
THIS MORNING AND ISOLATED THUNDERSTORMS THIS AFTERNOON. HIGH
PRESSURE WILL RESULT IN DRY CONDITIONS FROM TONIGHT THROUGH
SUNDAY. HOWEVER...A WEAK SURFACE LOW WILL TRY TO ENTER CENTRAL
INDIANA FROM THE SOUTH ON MONDAY...FOLLOWED BY A STRONGER COLD
FRONT THAT NIGHT WHICH WILL BRING ADDITIONAL SHOWER AND
THUNDERSTORM CHANCES INTO TUESDAY MORNING.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 955 AM EDT SAT AUG 10 2013
MID AND HIGH LEVEL CLOUDS PERSISTING SO FAR THIS MORNING ACROSS
ALL BUT NORTHERN PORTIONS OF THE FORECAST AREA. A FEW LIGHT
SHOWERS CONTINUE TO GRAZE FAR SOUTHERN COUNTIES AS A WEAK WAVE
ALOFT PASSES THROUGH THE LOWER OHIO VALLEY. TEMPS WERE GENERALLY
IN THE LOWER AND MIDDLE 70S AS OF 13Z.
FORECAST IN GOOD SHAPE THIS MORNING WITH JUST MINOR CHANGES
NEEDED. WEAK SURFACE WAVE ALONG SECONDARY FRONT NOTED ACROSS
NORTHEAST INDIANA WITH THE BOUNDARY EXTENDING SOUTHWEST INTO
CENTRAL ILLINOIS. THE BOUNDARY WILL PROGRESS SLOWLY SOUTH ACROSS
THE FORECAST AREA THROUGH THE AFTERNOON AND EVENING. WHILE FORCING
ALOFT REMAINS VERY WEAK...PRESENCE OF LOW LEVEL MOISTURE AND WEAK
INSTABILITY AHEAD OF THE BOUNDARY WILL LIKELY BE ENOUGH TO
GENERATE ISOLATED CONVECTION THROUGH THE AFTERNOON AND EARLY
EVENING...ESPECIALLY OVER THE SOUTHEAST HALF OF THE FORECAST AREA.
CURRENT HRRR CAPTURES THIS IDEA WELL...HINTING AT BEST POTENTIAL
FOR CONVECTIVE DEVELOPMENT OVER EASTERN COUNTIES WHICH MAKES SENSE
WITH SLIGHTLY BETTER FORCING ALOFT TO THE EAST OVER OHIO. WILL
MAINTAIN LOW CHANCE POPS THROUGH THE AFTERNOON OVER ALL BUT THE
NORTHERN WABASH VALLEY...AND INTO THE EVENING OVER FAR SOUTHERN
COUNTIES.
BUMPED UP HIGHS IN NORTHERN COUNTIES BY A DEGREE OR TWO...
ESPECIALLY WITH A MAINLY SUNNY START BEFORE CU FIELD DEVELOPS
LATER TODAY. OTHERWISE FORECAST HIGH TEMPS LOOK REASONABLE.
ZONE AND GRID UPDATES OUT.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
ISSUED AT 339 AM EDT SAT AUG 10 2013
HIGH PRESSURE WILL BUILD INTO CENTRAL INDIANA TONIGHT...INFLUENCING
THE AREA THROUGH SUNDAY NIGHT. THE NEXT CHANCE FOR ANY MEASURABLE
PRECIP WILL BE MONDAY/MONDAY NIGHT AS A COLD FRONT ENTERS FROM THE
NORTHWEST. THIS FRONT WILL COMBINE WITH SOME MOISTURE RETROGRADING
BACK INTO THE REGION. AS A RESULT...CHANCE POPS SEEM REASONABLE AT
THIS TIME DURING THE MONDAY/MONDAY NIGHT TIME FRAME.
TEMPS...MODELS ARE SHOWING SOME INCONSISTENCY WITH REGARD TO
CHANGING WEATHER PATTERN AT END OF SHORT TERM PERIOD. WENT WITH A
BLEND FROM TONIGHT THROUGH SUNDAY NIGHT...AND THEN LEANED TOWARD
THE WARMER GFS ON MONDAY TO CAPTURE ANY WARM AIR ADVECTION WITH A
SURFACE WARM FRONT.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
ISSUED AT 339 AM EDT SAT AUG 10 2013
ENSEMBLES INDICATE A RATHER STABLE WEATHER PATTERN DURING THIS
PERIOD. SUBTROPICAL RIDGE REMAINS ALONG THE GULF COAST/SOUTHERN
PLAINS REGION...WHILE UPPER TROUGHING CONTINUES OVER THE GREAT LAKES
AND NEW ENGLAND.
ENSEMBLES SUGGEST AN UPPER DISTURBANCE WILL BE IN THE PROCESS OF
PASSING OVER THE GREAT LAKES ON TUESDAY. WILL KEEP SOME CHANCE POPS
IN THE FORECAST ON TUESDAY TO COVER THIS FEATURE.
OTHERWISE...ENSEMBLES INDICATING LITTLE THREAT FOR PRECIPITATION FOR
THE REST OF THE EXTENDED...SO WILL GO DRY AFTER TUESDAY.
&&
.AVIATION /DISCUSSION FOR THE 101200Z TAFS/...
ISSUED AT 640 AM EDT SAT AUG 10 2013
SOME SPRINKLES POSSIBLE IN THE VICINITY OF THE TAF SITES THROUGH
ABOUT MID MORNING...OTHERWISE CONVECTIVE PARAMETERS SUGGEST ANY DEEP
CONVECTION WILL BE SOUTH OF THE TAF SITES TODAY.
SOME DIURNAL CLOUDS BASED AROUND 030 EXPECTED TO DEVELOP TOWARDS THE
MIDDAY HOURS.
NO VISIBILITY OR WIND ISSUES EXPECTED AT THE TAF SITES THROUGH
110000Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...RYAN
SHORT TERM...TDUD
LONG TERM....JAS
AVIATION...JAS
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
745 AM EDT SAT AUG 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM EDT SAT AUG 10 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL LOW OVER NRN
QUEBEC RESULTING IN WNW FLOW THROUGH THE NRN GREAT LAKES. THE MOST
PROMINENT UPSTREAM SHORTWAVE TROUGH WAS LOCATED OVER SW SASK. AT THE
SFC...A WEAK TROUGH EXTENDED FROM JAMES BAY INTO NE LAKE SUPERIOR
WHILE A RIDGE EXTENDED FROM ND INTO MN AND IA. IR LOOP SHOWED MAINLY
CLEAR SKIES OVER UPPER MICHIGAN WHICH HAS ALLOWED TEMPS TO DROP INTO
THE LOWER TO MID 40S INLAND. THE NRN EDGE OF A MORE EXTENSIVE AREA OF
CLOUD HAS REMAINED TO THE WEST AND SOUTH FROM NEAR ASX TO MNM.
TODAY...WITH THE WEAK 850-700 MB THERMAL TROUGH REMAINING NEAR THE
AREA...EXPECT SCT/BKN CU TO AGAIN DEVELOP THIS AFTERNOON. EVEN WITH
PROMINENT LAKE BREEZE BOUNDARIES THIS AFTERNOON IN THE RELATIVELY
LIGHT WIND FIELD...A STRONG CAP/INVERSION AROUND 700 MB...PER MDLS
SOUNDINGS AND AREA 00Z RAOBS...AND DRY LOW LEVELS WILL INHIBIT ANY
PCPN. NO MORE THAN A BRIEF SPRINKLE WOULD BE EXPECTED OUT OF THE
RELATIVELY SHALLOW CONVECTIVE CLOUDS. TEMPS WILL CLIMB TO NEAR
NORMAL...IN THE LOWER TO MID 70S.
TONIGHT...THE SASK SHRTWV WILL APPROACH UPPER MI TONIGHT BUT ANY
PCPN WITH THIS FEATURE IS EXPECTED TO REMAIN TO THE W OF THE CWA.
THE SIGNFICANT PCPN WILL REMAIN WELL TO THE SOUTH...CLOSER TO THE
850 MB FRONT OVER SRN MN. INCREASING MID CLOUDS LATE WILL KEEP TEMPS
FROM FALLING OFF AS MUCH WITH MIN READINGS IN THE MID 40S TO LOWER
50S.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 358 AM EDT SAT AUG 10 2013
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED SUNDAY
AFTERNOON AND MONDAY BEFORE BROAD HIGH PRESSURE GAINS CONTROL OF THE
REGION AND BRINGS AN EXTENDED PERIOD OF DRY WEATHER THROUGH THE
UPCOMING WEEK. TEMPERATURES WILL CONTINUE TO BE SLIGHTLY BELOW
NORMAL...WITH A COUPLE CHILLY NIGHTS EXPECTED FOR THE FIRST PART OF
THE WEEK.
SUNDAY...A BROAD MID-LEVEL TROUGH CENTERED OVER FAR NORTHERN
ONTARIO WILL BE MAKING A SOUTHWARD PUSH AT THE START OF THE PERIOD.
MAIN FORECAST FOCUS CONTINUES TO BE ON THE POTENTIAL FOR AFTERNOON
SHOWERS AND THUNDER ACROSS INTERIOR PORTIONS OF THE CWA. MODEL
GUIDANCE HAS BEEN QUITE PERSISTENT FOR SEVERAL NIGHTS NOW WITH
ADVERTISING THE PASSAGE OF A LEAD SHORTWAVE ACROSS UPPER MI ON
SUNDAY AFTERNOON AND EVENING. THIS WAVE IS A RESULT OF PHASING
BETWEEN SMALL PIECES OF ENERGY FROM WESTERN CANADA AND THE LARGER
TROUGH. THE ECMWF AND GEM ARE THE QUICKEST...AND HAVE THE TROUGH
OUTRUNNING PEAK HEATING BY CLEARING THE EASTERN CWA BY MID
AFTERNOON. THE NAM/LOCAL WRF/GFS ARE SLOWER...AND BRING THE WAVE
ACROSS THE CENTRAL CWA AROUND EARLY AFTERNOON. SUBTLE NW FLOW
FEATURES CAN BE QUITE FICKLE THIS TIME OF YEAR...SO AM NOT TOO
CONFIDENT IN JUMPING ON EITHER SOLUTION ATTM. GIVEN COMPETING
DYNAMICS BETWEEN THE MID-LEVEL WAVE AND THE LEFT ENTRANCE OF AN 80
KT UPPER JET...WILL MAINTAIN THE FOCUS FOR PRECIP CHANCES ACROSS THE
SOUTH CENTRAL AND INTERIOR EAST WHERE ASSISTANCE FROM LAKE BREEZE
CONVERGENCE WILL BOOST DIURNAL ACTIVITY.
ONE CONCERN WITH THUNDER POTENTIAL OVER THE PAST COUPLES DAYS HAS
BEEN LOWER INSTABILITY DUE TO CLOUDS FROM CONVECTION TO THE SOUTH.
WITH MLCAPE PEAKING AT ONLY 500 J/KG FAR SOUTH CENTRAL...THUNDER
COVERAGE WILL BE LIMITED. A DRY SUBCLOUD LAYER COULD STILL RESULT IN
SOME GUSTY WINDS TO 35 MPH WITH ANY SHOWERS THOUGH AS DOWNDRAFT CAPE
WILL BE OVER 500 J/KG.
SUNDAY NIGHT AND MONDAY...ANY ACTIVITY SUNDAY AFTERNOON SHOULD
DIMINISH WITH THE PASSAGE OF THE WAVE AND LOSS OF DAYTIME HEATING. A
WEAK SFC TROUGH ASSOCIATED WITH THE MID-LEVEL TROUGH WILL STILL BE
DRIFTING ACROSS THE EASTERN CWA INTO THE OVERNIGHT HOURS...BUT DO
NOT EXPECT ANY LINGERING SHOWERS GIVEN WEAK LIFT AND DRIER AIR. THE
MAIN TROUGH IS THEN PROGGED TO CROSS THE CWA DURING THE DAY ON
MONDAY. MID-LEVEL Q-VECTOR CONVERGENCE WITH A DECENT UPPER-LEVEL
NEGATIVE PV ANOMALY WILL BRING MODEST LIFT ACROSS THE NORTHERN CWA
AND LAKE SUPERIOR MONDAY AFTERNOON. ONCE AGAIN...DAYTIME HEATING
WILL ASSIST WITH PRECIP COVERAGE IN THE AFTERNOON. DO NOT EXPECT ANY
MORE COVERAGE THAN SUNDAY AFTERNOON AS MID-LEVEL CAPPING BEHIND
SUNDAYS TROUGH WILL LIMIT VERTICAL GROWTH OF ANY SHOWERS. WILL
MAINTAIN GOING FORECAST WITH BEST CHANCE POPS AND SLIGHT CHANCE OF
THUNDER SOUTH-CENTRAL AND INTERIOR EAST IN THE AFTERNOON.
TUESDAY THROUGH FRIDAY...HIGH PRESSURE WILL BUILD INTO THE CWA FROM
THE WEST BEGINNING MONDAY NIGHT AND SETTLE OVER THE REGION TUESDAY
NIGHT. PWAT VALUES OF 0.5 INCHES OR LESS AND LIGHT WINDS WILL LEAD
TO GREAT RADIATIONAL COOLING BOTH MONDAY AND TUESDAY NIGHTS.
GUIDANCE THAT HAS VERIFIED THE BEST OVER RECENT COOL NIGHTS PRODUCES
MIN TEMPS WELL INTO THE 40S INLAND...ESPECIALLY TUESDAY NIGHT. COULD
EVEN SEE SOME UPPER 30S TUESDAY NIGHT AT THE TYPICAL COOL
SPOTS...BUT DID NOT GO THAT LOW QUITE YET GIVEN UNCERTAINTY IN THE
EXACT PLACEMENT OF THE SFC HIGH. OVERALL...LOWERED TEMPS BY A COUPLE
DEGREES FOR BOTH NIGHTS. ALSO ADDED SOME PATCHY FOG ACROSS THE
INTERIOR WEST HALF MONDAY NIGHT SINCE THEY WILL HAVE SEEN A FEW
SHOWERS ON MONDAY AFTERNOON AND CROSSOVER TEMPS SHOULD BE SURPASSED
BY SEVERAL DEGREES.
ANOTHER WEAK TROUGH AXIS FROM THE MAIN EASTERN CANADIAN TROUGH WILL
SKIRT NE LAKE SUPERIOR THURSDAY. WITH MOISTURE LACKING AND BEST
DYNAMICS WELL NORTHEAST...KEPT PRECIP OUT OF THE FORECAST. A
PACIFIC-BASED WAVE COULD BEGIN AFFECTING THE WEST BY LATE
FRIDAY...BUT MODEL CONSISTENCY HAS BEEN POOR SO CONFIDENCE IS LOW IN
ANY PRECIP LATE IN THE WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 743 AM EDT SAT AUG 10 2013
VFR CONDITIONS ARE EXPECTED AT ALL THREE TAF SITES THIS FORECAST
PERIOD. KSAW WILL SEE A NE LAKE BREEZE SAT AFTERNOON. &&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 500 AM EDT SAT AUG 10 2013
HIGH PRESSURE MOVING INTO THE WRN GREAT LAKES WILL BRING RELATIVELY
LIGHT WINDS BELOW 20 KNOTS THROUGH THE WEEKEND. A WEAK TROUGH WILL
CROSS THE GREAT LAKES MONDAY...BUT AGAIN...WINDS WILL REMAIN LESS
THAN 20 KNOTS. HIGH PRESSURE WILL RESUME CONTROL OF THE WRN GREAT
LAKES TUESDAY THROUGH THE END OF THE WEEK TO KEEP WINDS GENERALLY
LIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KLUBER
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
635 AM CDT Sat Aug 10 2013
.SHORT TERM: (Through Late This Afternoon)
Issued at 317 AM CDT Sat Aug 10 2013
Early morning precipitation over eastern OK and southern MO was
being handled fairly well by the RAP. Based on RAP forecasts of H85
moisture convergence, SHRA/TSRA over southern MO/IL should begin to
taper off after 15Z. Heavy downpours are still possible this morning
since PW values remain near 2 inches. With a surface high pressure
center building into the region and a drier air mass spreading
southward today, any afternoon convection should be confined to
areas closer to the active quasistationary front near the MO/AR
border.
Kanofsky
.LONG TERM: (Tonight through Friday)
Issued at 317 AM CDT Sat Aug 10 2013
All of the 00z NWP output is much more aggressive with the southward
surge of the surface ridge into the mid Mississippi Valley tonight
and into Sunday. Not only will this mean lower dewpoints and
slightly cooler temps, but this will also give the stubborn
baroclinic zone that has been anchored over southern Missouri and
northern Arkansas a gentle but significant southward nudge. This
will greatly lessen the threat of convection that has seemingly
been a nightly occurrence for almost a week over southern Missouri.
I have held onto some low pops in our southern counties both tonight
and Sunday just in case the later solutions back off on the
southward push of the ridge, but if 00z guidance verifies with its
trends any rainfall tonight and Sunday should primarily fall south
of our CWA.
Surface ridge still expected to retreat Sunday night into Monday,
allowing the resultant return flow to cause a northward return of
the warm and moist air. Have continued slight chance pops for most
areas on Sunday night, but it would appear better threat for
convection will hold off until Monday when shortwave energy will be
able to interact with a diurnal increase of instability. This
threat should continue into Monday night. These thunderstorm
chances should shut down with the arrival of the next front...which
the 00z guidance suggests will be about 12 hours slower that earlier
solutions. POPS should diminish from north to south Monday night and
Tuesday.
Consensus of tonight`s medium range guidance dovetails with that of
yesterday`s day shift, and indicates a fairly significant deepening
of the upper trof that is progged to form over the Great Lakes and
eastern U.S during the latter half of next week. This in turn means
stronger high pressure and a bit more of the associated Canadian
airmass backdooring into region. Going trends for the
Wednesday-Friday frame still look very good, with this early surge
of Canadian air providing the region with unseasonably low
humidities and cooler than average temperatures for mid August, and
little if any threat of rain.
Truett
&&
.AVIATION: (For the 12z TAFs through 12z Sunday Morning)
Issued at 620 AM CDT Sat Aug 10 2013
Patchy light fog will quickly dissipate this morning, leaving VFR
conditions for the rest of the TAF period. Precipitation should
remain well to the south of the terminals since the active frontal
boundary is near the MO/AR border.
Specifics for KSTL: VFR through the period with light northerly
winds.
Kanofsky
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS GLASGOW MT
944 AM MDT SAT AUG 10 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH MONDAY...
UPDATE...
PLACED THE ENTIRE CWA IN ISOLATED POPS THIS MORNING WITH THUNDER
MENTION GIVEN CURRENT RADAR OBSERVATIONS. FORECAST SOUNDINGS
INDICATE HIGHEST CAPE THIS AFTERNOON/EVENING ACROSS THE
SOUTHEASTERN ZONES. HRRR INDICATES CONVECTION INITIATION ACROSS
THE CWA AND PUSHING THROUGH THE EAST/SOUTHEAST AS WELL. THIS HAS
ADDITIONAL SUPPORT FROM THE 10/00Z ECMWF AS WELL AS 10/12Z NAM/GFS
WHICH ALL HAVE QPF IN THE SOUTHEAST TODAY. WILL PLACE THESE AREAS
IN SCATTERED SHOWERS AND THUNDERSTORMS. VISIBLE SATELLITE IMAGERY
SHOWS MORE IN THE WAY OF SUNSHINE THERE AS WELL THIS MORNING WHICH
COULD CONTINUE TO DESTABILIZE THE ENVIRONMENT...MAKING IT MORE
CONDUCIVE FOR A FEW STORMS TO BECOME ON THE STRONGER SIDE. THE
SSEO FROM SPC SHOWS BEST POTENTIAL FOR SEVERE STORMS TO BE JUST TO
THE SOUTH AND EAST OF THE CWA SO WILL NOT INCLUDE SEVERE WORDING
IN THE GRIDS. DID PLACE GUSTY WINDS/SMALL HAIL HOWEVER...MAINLY
SOUTH OF THE MISSOURI RIVER. BEST CONFIDENCE FOR STRONGER STORMS
IS AGAIN IN THE SOUTHEASTERN PORTIONS OF THE CWA FOR THIS
AFTERNOON AND EVENING. MALIAWCO
PREVIOUS SHORT TERM DISCUSSION... WATER VAPOR IMAGERY AND 500 MB
HEIGHT FIELD SHOWS THE SLOWLY EVOLVING WEATHER PATTERN ACROSS THE
CONUS. THE CLOSED UPPER LOW PRESSURE SYSTEM OVER THE PACIFIC
COASTLINE IS SLOWLY WEAKENING AS IT MOVES NORTHWARD. THE STRONGER
WAVES OF THE HUDSON BAY UPPER LOW COMPLEX ARE SPINNING A BIT
FURTHER EASTWARD THAN THEY WERE BEFORE TODAY. BOTH OF THESE
MOVEMENTS ALLOWS THE RIDGE OF HIGH PRESSURE OVER THE SOUTHERN HIGH
PLAINS AND SOUTHERN ROCKIES REGIONS TO SLOWLY BUILD NORTHWARD.
THIS WEATHER REGIME EVOLVEMENT IS EXPECTED TO CONTINUE...PLACING
THE UPPER LEVEL RIDGE AXIS OVER MONTANA BY THE END OF THIS
FORECAST PERIOD...WHICH WILL GENERALLY ALLOW TEMPERATURES TO CLIMB
ABOVE NORMAL THROUGH THE END OF NEXT WEEK.
THE FORECAST CHALLENGES WILL FOCUS ON THE TIMING...PLACEMENT...AND
INTENSITY OF ANY THUNDERSTORMS WHICH DO HAPPEN TO DEVELOP.
ALTHOUGH ALL BUT THE NORTHEASTERN THIRD OF OUR CWA IS OUTLINED FOR
GENERAL THUNDERSTORMS LATER TODAY AND TONIGHT...THE LACK OF
CONSISTENCY BETWEEN DIFFERENT MODEL SOLUTIONS AND EVEN BETWEEN ANY
INDIVIDUAL MODELS SUBSEQUENT RUNS SIGNIFICANTLY REDUCES THE
FORECAST CONFIDENCE. FEEL IT WOULD BE MOST PRUDENT TO EMPHASIZE
THE FEW SIMILARITIES WITH SLIGHTLY HIGHER POPS...BUT FILL IN THE
REST WITH ISOLATED SPRINKLES AT TIMES.
FOR EXAMPLE...THE NAM AND EC ARE EMPHASIZING THE STORMS TONIGHT
MORE WHILE THE GFS IS VIRTUALLY QUIET. THIS SAME SCENARIO SETS UP
FOR SUNDAY NIGHT AS WELL. EVEN THOUGH SOME INSTABILITY IS
PRESENT...I WOULD NOT IMAGINE MUCH WILL COME OF IT GIVEN THE LACK
OF MODEL AGREEMENT. BMICKELSON
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...
UPPER RIDGE GRADUALLY BUILDS INTO MONTANA DURING THE EXTENDED
PERIOD.
FOR TUESDAY AND WEDNESDAY...THERE WILL BE A SLOW MOVING WARM FRONT
WHICH WILL BE THE FOCUS FOR SHOWERS AND THUNDERSTORMS AT TIMES.
THE STORMS WILL BE PARTLY DRIVEN BY DAYTIME INSTABILITY AND PARTLY
DRIVEN BY SHORTWAVES THAT OVERTOP THE RIDGE AXIS. MODELS TIME THE
WAVES DIFFERENTLY WHICH RESULTS IN MODELS TIMING THE STORMS
DIFFERENTLY. AT THIS POINT... IT LOOKS LIKE THE BEST CHANCE FOR
STORMS WILL BE WEDNESDAY AFTERNOON AND EVENING WHEN THE WARM FRONT
IS OVER EASTERN MONTANA. IT MAY BE UNSTABLE ENOUGH FOR SEVERE
STORMS ON WEDNESDAY. THE CHANCES OF SHOWERS AND THUNDERSTORMS
COULD LINGER INTO THURSDAY DEPENDING ON HOW FAST THE FRONT MOVES
EAST.
BY FRIDAY...THE UPPER RIDGE TAKES CONTROL OF THE WEATHER.
TEMPERATURES WILL WARM TO NEAR 90 POSSIBLY WARMER BOTH FRIDAY AND
SATURDAY WITH LITTLE OR NO CHANCE OF PRECIPITATION. FORRESTER
&&
.AVIATION...
VFR. EXPECT SCATTERED SHOWERS AND/OR THUNDERSTORMS LATER
TODAY...ESPECIALLY TO KGDV. EXPECT GUSTY/ERRATIC WINDS...BRIEF
HEAVY RAIN AND POSSIBLY HAIL. TFJ
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS PORTLAND OR
259 AM PDT SAT AUG 10 2013
.SYNOPSIS...AN UPPER LOW OVER THE NORTHERN CALIFORNIA COAST
WILL MOVE NORTH ALONG THE OREGON COAST THROUGH TONIGHT
...AND ALONG THE WASHINGTON COAST LATE SUNDAY INTO MONDAY. THIS WILL
CONTINUE THE THREAT OF SHOWERS AND THUNDERSTORMS THROUGH THE WEEKEND.
DRIER WEATHER WITH SEASONABLE TEMPERATURES WILL RETURN AS THE LOW
DEPARTS THE AREA ON MONDAY AND CONTINUE THROUGH MOST OF NEXT WEEK.
&&
SHORT TERM...TODAY THROUGH SUNDAY...NEARLY STATIONARY UPPER LEVEL LOW
PRESSURE ALONG THE COAST IS BEGINNING TO MAKE A NORTHWARD MOVEMENT
TODAY. WE CURRENTLY HAVE SOME SHOWERS DRIFTING EASTWARD THROUGH THE
NORTHERN HALF OF THE AREA EARLY THIS MORNING...WITH THUNDERSTORM
ACTIVITY CONFINED ALL AROUND US WHERE GREATER INSTABILITY WAS
LOCATED. THERE ARE STORMS NORTH AND EAST OF THE COUNTY WARNING AREA
IN WEST CENTRAL WASHINGTON WITH A REMOVED WEAKENED CLUSTER OF
THUNDERSTORMS IN NORTH CENTRAL/EASTERN OREGON WHERE A SHORTWAVE IS
MOVING THROUGH...AND SOUTH OF THE AREA CLOSER TO THE UPPER LOW. SPC
WRF AND HRRR SUGGEST THAT THE ACTIVITY ALONG THE NORTHERN TIER WILL
CONTINUE TO TRACK EASTWARD WITH THE SHOWER ACTIVITY MOVING OFFSHORE
AT DAYBREAK. THE ELEVATED SHOWERS/ISOLATED T-STORMS IN SOUTHERN
OREGON MAY MAKE A RUN AT OUR SOUTHERN ZONES THIS MORNING AS ANOTHER
WAVE WRAPS AROUND THE UPPER LOW...LIKELY GETTING IN AFTER DAYBREAK.
ADDITIONAL CONVECTION IN SOUTH CENTRAL OREGON WILL HEAD TOWARD THE N
OR/ S WA CASCADES LATER THIS MORNING THOUGH GUIDANCE IS MIXED AS TO
WHETHER THIS WILL SNEAK IN.
MEANWHILE...STRATUS HAS RETURNED INLAND UP THE COLUMBIA RIVER AND IS
NOW AT KELSO...AND BREAKS IN THE HIGHER CLOUDS IS ALLOWING THE FOG
PRODUCT TO MAKE OUT SOME LOW CLOUDS ALONG THE FOOTHILLS AS WELL. THE
REMAINDER OF THE AREA JUST HAS A MIX OF MID CLOUDS THUS FAR. IT IS
MOIST OUT THERE WITH DEWPOINTS IN THE MID 50S TO LOW 60S.
OUR ATTENTION WILL THEN FOCUS ON THE UPPER LOW AS IT WILL BE MOVING
NORTH ALONG THE COAST THROUGH THE AFTERNOON. THIS IS ABOUT AS GOOD OF
A SETUP AS IT GETS FOR THUNDER WEST OF THE CASCADES IN NORTHWEST
OREGON AND SOUTHWEST WASHINGTON. THE TRIGGER/INITIATION POINT FOR
MORE WIDESPREAD CONVECTION WILL BE ALOT CLOSER TODAY WITH THE UPPER
LOW FARTHER NORTH AND WEST THAN IT HAS BEEN IN DAYS PAST...AND AIDED
WITH THE MOMENTUM/NEGATIVE TILT OF THE LOW AND NOT JUST IMPULSES
ROTATING OUT AHEAD OF IT. HI-RES GUIDANCE SHOWS CONVECTIVE INITIATION
OVER THE CENTRAL OREGON CASCADES AND FOOTHILLS INTO CENTRAL AND
SOUTHERN OREGON IN THE EARLY AFTERNOON AS DIURNAL HEATING COMBINES
WITH GOOD FORCING FOR ASCENT ON THE NORTH AND EAST SIDE OF THE UPPER
LOW. SOUTH-SOUTHEAST STEERING FLOW REMAINS IN PLACE TO AID IN
DRIFTING STORMS OFF THE CASCADES WHERE THEY MAY NOT QUITE GET SURFACE
BASED. AREAS FARTHEST WEST WILL BE BATTLING THE STRONG ONSHORE
FLOW...THOUGH NO AREA IS IMMUNE TO A CHANCE.
INSTABILITY PARAMETERS ARE RIGHT ON PAR FOR THE CASCADES AND MUCH
BETTER FOR THE VALLEY THAN FRIDAY`S VALUES. MID LEVEL LAPSE RATES
OVER THE VALLEY ARE BETTER...AND CAPPING IS SIGNIFICANTLY LESS.
HAZARDS INCLUDE THE POTENTIAL FOR HAIL...GUSTY WINDS...AND HEAVY
RAIN...IN ADDITION TO ANOTHER ROUND OF ABUNDANT LIGHTNING. CAPE IN
THE -10 TO -30 C LEVEL IS FAVORABLE FOR HAIL PRODUCTION GIVEN THE
STEEP MID LEVEL LAPSE RATES THAT TYPICALLY OCCUR IN PROXIMITY TO THE
UPPER LOW. FREEZING LEVELS WILL BE AROUND 11-12K FT...SO ANY 50DBZ
ECHOES ABOVE ROUGHLY 30K FT AGL HAVE THE POTENTIAL FOR SEVERE HAIL.
FORECAST SOUNDINGS DEPICT SOMEWHAT DRY SUBCLOUD LAYERS WHICH
CONTRIBUTES TO MODEST DOWNDRAFT CAPE VALUES INCREASING THE WIND
THREAT. AND CORFIDI VECTORS SUGGEST LOW TO MODERATE STORM
MOTION....AND THIS COUPLED WITH A SLOW MOVING UPPER LOW AND
PRECIPITABLE WATER VALUES ABOVE 1 INCH TO EVEN AS HIGH AS 1.25 INCHES
WILL BRING THE POTENTIAL FOR VERY MODERATE TO HEAVY RAIN UNDER ANY
THUNDERSTORMS.. SPC`S DAY 1 OUTLOOK SUMS THINGS UP WELL...AND EXPECT
DISCRETE STORMS TO DEVELOP INTO A FEW MULTICELL CLUSTERS CAPABLE OF
MARGINALLY SEVERE HAIL AND ISOLATED DAMAGING WINDS.
THE LOW WILL EVENTUALLY REACH THE SOUTH WASHINGTON COAST LATE SUNDAY
AND SUNDAY NIGHT. THIS SHOULD CONTINUE TO SPREAD SOME SHOWERS AND
THUNDERSTORMS ON SUNDAY MAINLY INTO THE CASCADES WHERE THE MODELS
SHOW LINGERING INSTABILITY AND MODEST SHEAR...THOUGH MOISTURE
PARAMETERS ARE WEAKER AS IS FORCING. AFTER THE LEFTOVER CLOUDS AND
SHOWERS FROM THE CONVECTION OF SATURDAY NIGHT MOVE OUT SUNDAY
MORNING...EXPECT ONSHORE FLOW WEST OF THE CASCADES TO BE FAIRLY
STRONG BRINGING MORE AND DEEPER LOW CLOUDS...AND KEEPING THE NOW
SMALLER THUNDER CHANCES TO THE HIGH TERRAIN.
WITH THE LOW OFF THE WASHINGTON COAST ON MONDAY...EXPECT A BIT MORE
SUNSHINE ON MONDAY AFTERNOON AFTER THE MORNING CLOUDS BURN OFF. THE
BEST CHANCE OF ANY THUNDER ON MONDAY WILL BE IN THE HIGHER CASCADES.
NOT MUCH WAS CHANGED ON THE FORECAST BEYOND THE SHORT TERM...GIVEN
THE FOCUS ON THE HIGH IMPACT SHORT TERM FORECAST. KMD
.LONG TERM...MONDAY NIGHT THROUGH THURSDAY...THE MODELS SHOW THE LOW
FROM THE WEEKEND WELL NORTH AND OFF THE COAST THROUGH THE PERIOD...
WITH ANOTHER LOW SETTING UP WELL OFFSHORE OUT NEAR 140W OR SO. THIS
PUTS SOUTHWEST WASHINGTON AND NORTHWEST OREGON IN LIGHT SOUTHWEST
FLOW THAT SHOULD MAINTAIN LIGHT ONSHORE FLOW AND SEASONABLE TO
SLIGHTLY ABOVE NORMAL TEMPS. THE MAIN THUNDERSTORM THREAT MAY STAY
JUST TO OUR EAST. THE ECMWF AND GEM START TO ALLOW THE OFFSHORE LOW
TO APPROACH OUR AREA BY NEXT THURSDAY...BUT FOR NOW WILL HOLD OFF ON
ANY PRECIPITATION OR TOO MUCH COOLING UNTIL THIS TREND BECOMES MORE
ESTABLISHED. TOLLESON
&&
.AVIATION...IFR CONDITIONS WILL CONTINUE ALONG THE COAST TODAY AND
TONIGHT...WITH PERHAPS SOME BRIEF IMPROVEMENT TO MVFR ALONG THE
NORTH COAST DURING THE AFTERNOON. ONSHORE FLOW SHOULD BRING MVFR
STRATUS TO MOST OF THE WILLAMETTE VALLEY AND THE SOUTHWEST
WASHINGTON LOWLANDS THIS MORNING. VFR CONDITIONS WILL LIKELY
RETURN BY 18-20Z. THERE WILL LIKELY BE A THREAT OF SHOWERS AND
THUNDERSTORMS THIS AFTERNOON AND EVENING...PARTICULARLY ACROSS
NORTHERN PARTS OF THE DISTRICT.
KPDX AND APPROACHES...MVFR CONDITIONS WILL LIKELY DEVELOP AROUND
12Z THIS MORNING AND CONTINUE THROUGH 18-19Z. EXPECT VFR
CONDITIONS THEREAFTER. SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE
LATER TODAY...PARTICULARLY AFTER 20Z.
&&
.MARINE...LITTLE CHANGE EXPECTED THROUGH EARLY NEXT WEEK WITH N
TO NW WINDS GENERALLY REMAINING IN THE 10 TO 20 KT RANGE.
OTHERWISE...A 4 TO 6 FT WESTERLY SWELL WILL SLOWLY SUBSIDE TODAY
AND SUNDAY...DROPPING SEAS BACK DOWN INTO THE 3 FT RANGE FOR
EARLY NEXT WEEK.
&&
.FIRE WEATHER...RED FLAG WARNING FOR ZONES 606 AND 608 HAS EXPIRED AS
THERE WERE WETTING RAINS IN PORTIONS OF THIS AREA. THE RED FLAG
REMAINS IN ZONES 660...605 AND 607 THROUGH SATURDAY AT THIS
POINT...DUE TO VERY ABUNDANT LIGHTNING EXPECTED AS WAS SEEN ON
FRIDAY...THOUGH THERE WERE SOME WETTING RAINS HERE TOO.
THUNDERSTORMS WILL INCREASINGLY SPREAD NORTH AND BECOME INCREASINGLY
WET AGAIN THIS AFTERNOON AND EVENING.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...RED FLAG WARNING UNTIL 11 PM PDT SATURDAY FOR ZONE 605-ZONE 607.
WA...RED FLAG WARNING UNTIL 11 PM PDT SATURDAY FOR ZONE 660.
PZ...NONE.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.PORTLAND.GOV
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1027 AM CDT SAT AUG 10 2013
.UPDATE...
CLUSTERS OF SHOWERS WITH EMBEDDED STORMS PASSING ACROSS THE
SOUTHEASTERN CWA THIS MORNING...THE MAJORITY OF THIS MORNING`S
ACTIVITY OCCURRING SOUTH OF THE I-10 / EAST OF THE I-45 CORRIDORS.
GENERALLY...THE SOUTHERN THIRD OF THE FORECAST AREA WILL EXPERIENCE
PERIODIC SHOWERS AND THUNDER THROUGH MID-LATE AFTERNOON...LOCALLY
HEAVY RAIN ACCUMULATIONS OF BETWEEN A HALF AN INCH TO AN INCH.
A 2.2 TO 2.4 INCH PWAT MOISTURE RIDGE NOSING UP INTO THE NORTHWESTERN
GULF...WITH DECENT MID-UPPER CONVERGENCE ALONG THE WESTERN EDGE OF
THIS CENTRAL GULF CYCLONIC CIRCULATION...WILL KEEP MODERATE TO
HIGH PRECIPITATION CHANCES IN PLACE THROUGH THE WARMTH OF THE DAY.
RELATIVELY LOW CONVECTIVE TEMPERATURES IN THE MID TO UPPER 80S AND
LOCAL AREA SOUNDINGS DISPLAYING MU CAPES OF ABOVE 3K J/KG INDICATE
CONTINUED INLAND CONVECTIVE COVERAGE. EARLY SKC UP NORTH SHOULD
GIVE THOSE ACROSS THE NORTHERN CWA A HEAD START IN ACHIEVING UPPER
90F MAXIMUM TEMPERATURES...LOWER 90 MAX TEMPS ACROSS (NEAR) COASTAL
REGIONS THAT WILL BE UNDER OVERCAST SKIES/PERIODIC -TSRA FOR A GOOD
PART OF THE DAY. 31
&&
.PREV DISCUSSION... /ISSUED 622 AM CDT SAT AUG 10 2013/
AVIATION...
SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE COASTAL WATERS HAVE
REACHED THE COAST AND ARE BEGINNING TO PUSH INLAND ACROSS
SOUTHEAST TEXAS. THIS ACTIVITY WILL AFFECT MOST SITES BEFORE
DISSIPATING LATE THIS AFTERNOON. EXPECT A SIMILAR SITUATION ON
SUNDAY AS ANOTHER WEAK DISTURBANCE MOVES ACROSS THE COASTAL
WATERS. 38
&&
PREV DISCUSSION... /ISSUED 420 AM CDT SAT AUG 10 2013/
DISCUSSION...
COASTAL RADARS SHOW SCATTERED SHOWERS AND THUNDERSTORMS IN THE
GULF WATERS THIS MORNING. AIRMASS ALONG THE COAST AND IN THE NW
GULF HAS BECOME VERY MOIST WITH GOES SOUNDER PRECIP WATER IMAGERY
SHOWING 2-2.2 INCHES WHERE CONVECTION IS ONGOING. WATER VAPOR
IMAGERY SHOWS UPPER LOW IN THE EAST CENTRAL GULF WHICH WILL
CONTINUE TO MOVE WEST ACROSS THE GULF AND DRIVE DEEPER MOISTURE
INLAND TODAY. UPPER LEVEL RIDGE HAS WEAKENED SOME BUT STRETCHES
ACROSS TEXAS THROUGH THE SE US. THINK SUBSIDENCE FROM THE RIDGE
MAY HOLD OFF CONVECTION INLAND FOR A LITTLE WHILE THIS MORNING BUT
DAY TIME HEATING WILL BE TOO MUCH FOR SCATTERED SHOWERS AND
THUNDERSTORMS NOT TO FORM. THE 06Z HRRR SHOWS CONVECTIVE
DEVELOPMENT ALONG THE COAST MAINLY 14-18Z AND THEN SCATTERED
ACTIVITY FURTHER INLAND FROM 18-21Z. THINK POPS OF 40 ALONG THE
COAST TRIMMING TO 20 FAR INLAND LOOKS ON TRACK. MIGHT BE ENOUGH
ACTIVITY TO BRING 50 POPS INLAND ALONG THE COAST BUT WILL HOLD OFF
TO SEE WHAT KIND OF COVERAGE DEVELOPS THROUGH THE MORNING.
CONVECTION FOR SUNDAY COULD BE ABOUT THE SAME COVERAGE AS TODAY
BUT PERHAPS A LITTLE LESS. MOISTURE WILL NOT BE AS HIGH WITH
PRECIP WATER AROUND 1.9-2 INCHES INSTEAD OF 2.2 INCHES.
NAM/GFS/ECMWF ARE ALL IN PRETTY GOOD AGREEMENT WITH THE CENTER OF
THE UPPER LOW TRACKING TOWARDS THE RIO GRANDE VALLEY ON SUNDAY.
VORTICITY WITH THE SYSTEM ALSO WEAKENS AND SHEARS OUT AS IT MOVES
INLAND. STILL THINK 30/40 POPS LOOK ON TRACK WITH 20 POPS FOR MORE
INLAND AREAS. BUT IF NAM IS MORE RIGHT...COULD HAVE MORE ACTIVITY
ON SUNDAY THAN TODAY. THINK THE NAM IS OVERDOING THE CONVECTION ON
SUNDAY AS UPPER LEVEL SUPPORT WILL NOT BE AS FAVORABLE.
THINK RAIN CHANCES WILL BE LESS ON MONDAY WITH 20 POPS IN PLACE.
THERE IS STILL DECENT MOISTURE WITH PRECIP WATER OF 1.9 INCHES BUT
THE RIDGE MAY BEGIN TO RE-ESTABLISH ITSELF OVER TX AT THIS TIME.
AGAIN LOOKS LIKE DAY TIME HEATING WILL BE THE MAIN TRIGGER FOR
CONVECTION BUT MOST LIKELY TIME WILL BE DURING THE AFTERNOON.
THE MAIN HAZARDS THE NEXT COUPLE OF DAYS WILL BE BRIEF HEAVY
RAINFALL AND LIGHTNING. COULD SEE SOME GUSTY WINDS BUT OVERALL NOT
A SEVERE THREAT. RAINFALL AMOUNTS THROUGH THE WEEKEND WILL LIKELY
BE AROUND A QUARTER TO HALF INCH WITH ISOLATED 1 INCH AMOUNTS IN
STRONGER STORMS. RAINFALL WILL PROVIDE SOME AREAS WITH A LITTLE
BREAK IN THE DROUGHT BUT NO REAL RELIEF. THEN AGAIN THERE COULD BE
SOME AREAS THAT DO NOT PICK UP ANY RAINFALL FROM THIS ENVIRONMENT.
NONETHELESS THE CLOUD COVER SHOULD HELP KEEP TEMPS LOWER AND AS A
RESULT WILL NOT NEED A HEAT ADVISORY FOR TODAY. WE WILL BE BACK TO
NEEDING 2 CONSECUTIVE DAYS OF A 108F HEAT INDEX TO ISSUE AN
ADVISORY.
THERE DOES LOOK TO BE A PATTERN CHANGE FOR THE EXTENDED FORECAST.
UPPER LEVEL RIDGE SHOULD BUILD OVER TX TUE/WED BUT THEN BECOMES
MORE ESTABLISHED OVER THE S ROCKIES BY THUR. TROUGHING OVER THE
GREAT LAKES WILL STRETCH TOWARDS THE MISS RIVER VALLEY SO NW FLOW
ALOFT MAY SUPPORT A FRONT PUSHING INTO THE AREA. GFS/ECMWF ARE
SHOWING A STRONGER FRONT MOVING INTO THE AREA THUR/FRI NEXT WEEK
SO WILL KEEP SOME RAIN CHANCES IN THE FORECAST ASSOCIATED WITH THE
FRONT. DRIER AIR MAY KNOCK MIN/MAX TEMPS DOWN A COUPLE OF DEGREES.
MODELS AGREE WITH AMPLIFYING THE PATTERN NEXT WEEKEND SO THIS
PATTERN MAY PERSIST A BIT LONGER AND GIVE SE TX A DECENT BREAK
FROM THE HEAT. 39
&&
MARINE...
SCATTERED SHOWERS ONGOING ACROSS THE COASTAL WATERS THIS MORNING
AS A WEAK EASTERLY WAVE APPROACHES THE REGION. THIS FEATURE AND
ANOTHER DISTURBANCE EXPECTED ON SUNDAY WILL KEEP SCATTERED SHOWERS
AND THUNDERSTORMS ACROSS THE MARINE ZONES THROUGH THE WEEKEND. 38
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 99 78 98 75 97 / 20 20 20 20 20
HOUSTON (IAH) 93 78 95 77 95 / 40 20 40 20 20
GALVESTON (GLS) 88 83 90 81 91 / 60 30 40 20 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...31
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
933 AM CDT SAT AUG 10 2013
.DISCUSSION...MORNING SOUNDING AND SATELLITE DERIVED PRECIPITABLE
WATER ESTIMATES CONTINUE TO INDICATE A VERY SATURATED
AIRMASS...ASSOCIATED WITH A TROPICAL WAVE MOVING WESTWARD ACROSS
THE WEST CENTRAL GULF HAS MOVED INTO THE AREA. RAP AND MODIFIED
MORNING FORECAST SOUNDINGS INDICATE WE ARE APPROACHING CONVECTIVE
TEMPERATURE WITH LITTLE LOWER TROPOSPHERIC WARMING EXPECTED DUE TO
THE SATURATED AIRMASS AND CU STREAKS AND CONVERGENCE ZONES ARE
BECOMING READILY APPARENT ON VISIBLE SATELLITE IMAGERY. THE TWO
STRONGEST ZONES ARE ASSOCIATED WITH THE SEABREEZE IN EASTERN
CAMERON AND WILLACY COUNTY...AND DEVELOPING SHOWER ACTIVITY NEAR
WESLACO. A GENERALLY DIFFLUENT UPPER LEVEL PATTERN JUST OFFSHORE
IS PRODUCING WIDESPREAD SHOWERS AND A FEW THUNDERSTORMS OVER OUR
COASTAL WATERS FOCUSED ALONG WEAK SURFACE TROUGHING MOVING SLOWLY
WESTWARD UNDER THIS FEATURE.
ALL THAT BEING SAID EXPECTING CONVECTIVE DEVELOPMENT TO INCREASE
MARKEDLY OVER THE NEXT TWO TO THREE HOURS WITH SCATTERED TO
NUMEROUS SHOWERS AND STORMS DEVELOPING...POSSIBLY BECOMING
WIDESPREAD IF THE MORE FAVORABLE UPPER LEVEL ENVIRONMENT OVER THE
GULF MOVES ONSHORE. HOWEVER NEAR AND SHORT TERM GUIDANCE HAS BEEN
CONSISTENTLY SHOWING WEAKENING OF THIS FEATURE AS IT MOVES INLAND.
NEVERTHELESS THE CURRENT THERMODYNAMIC AND MOISTURE PROFILE WILL
PROVIDE SHRA/TSRA. THE SHOWERS SHOULD GREATLY OUTNUMBER THE STORMS
BUT THERE WILL PROBABLY BE A FEW RUMBLES OF THUNDER.
THE STRONGEST CELLS WILL PRODUCE EXCEPTIONALLY EFFICIENT RAINFALL
RATES...ON THE ORDER OF TWO TO THREE INCHES PER HOUR AS THEY MOVE
WEST AT AROUND 15 MPH. MOST CONVECTION WILL PROBABLY BE LESS
INTENSE HOWEVER...AND PRODUCE RAINFALL RATES CLOSER TO ONE HALF TO
TWO INCHES PER HOUR. TOTAL ACCUMULATIONS AT ANY ONE LOCATION WILL
LIKELY BE LESS AS THE ACTIVITY MOVES SLOWLY WESTWARD. THE GRIDDED
FORECASTS SHOW THE ANTICIPATED EVOLUTION WELL AND NO SIGNIFICANT
CHANGES ARE PLANNED FOR NOW. /68-JGG/
&&
.PREV DISCUSSION... /ISSUED 634 AM CDT SAT AUG 10 2013/
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
AVIATION...EXPECTING CONVECTION TO DEVELOP LATER THIS MORNING
FIRST ALONG THE COAST AND THEN MOVE INLAND THIS AFTERNOON.
EXPECTING BEST CHANCES AND COVERAGE BETWEEN 16-21Z IN THE EAST
AND 18-23Z IN THE CENTRAL AND WEST. VFR CONDITIONS TO PREVAIL
OUTSIDE OF THE CONVECTION WITH TEMPORARY MVFR CIGS VSBY IN AND
NEAR THE SCATTERED THUNDERSTORMS AND SHOWERS. MOISTURE VALUES TO
REMAIN RATHER HIGH SO EXPECT A LAYER OF STRATUS TO DEVELOP
OVERNIGHT AOA MVFR. SURFACE WIND TO REMAIN LIGHT FROM A GENERAL
EAST DIRECTION.
PREV DISCUSSION... /ISSUED 403 AM CDT SAT AUG 10 2013/
SHORT TERM /NOW THROUGH SUNDAY/...SATELLITE AND RADAR LOOPS
INDICATE MOISTURE IS BEGINNING TO MOVE INTO COASTAL WATERS.
SHOWERS AND AN ISOLATED THUNDERSTORM OR TWO HAVE BEEN MOVING INTO
NORTHEAST MEXICO SINCE 1AM IN ADVANCE OF THE LARGE SCALE MID TO
UPPER LEVEL TROUGH CENTERED JUST NORTH OF THE YUCATAN.
FOR TODAY...LOOKING AT SHOWERS THIS MORNING TO FAVOR THE IMMEDIATE
COASTAL AREAS AND THE GULF WATERS. NOT UNTIL THE MOISTURE COLUMN
BECOMES NEARLY SATURATED AROUND OR AFTER 18Z AND PWATS EXCEED 2.25
INCHES WILL WE SEE CONVECTION DEVELOP FARTHER INLAND. A DEEPENING
EASTERLY FLOW TO ENHANCE SURFACE CONVERGENCE ALONG THE SEABREEZE AND
DESTABILIZATION OF THE ATMOSPHERE AS SURFACE HEATING GETS GOING THIS
MORNING BEFORE THE CLOUDS INCREASE TO GIVE THE LOWER AND MID VALLEY
THE BEST AND HIGHEST CHANCE OF RAIN IN LONG WHILE. INHERITED
FORECAST LOOKS GOOD AND REMAINS IN LINE WITH LATEST GUIDANCE. DID
NOT MENTION HEAVY RAIN IN THE FORECAST WITH THE ANTICIPATION OF
CELLS TO MOVE STEADILY EAST TO WEST UNDER A 15 TO 20 KNOT MID LAYER
FLOW. SURFACE TROUGHING LOOKS TO REMAIN JUST OFFSHORE ALONG WITH
UPPER DIVERGENCE KEEPING CONVECTION INITIATION EAST OF THE COAST
WITH THE HEAVIEST AND MOST CONCENTRATED AREA OF RAIN OFFSHORE.
WITH THIS SAID POCKETS OF HEAVY RAIN ARE STILL POSSIBLE INLAND...AS
MOISTURE INCREASES...AND ANY WESTWARD SHIFT OF THE TROUGH COULD PUSH
THE HEAVIER RAIN INLAND. TEMPERATURES TO CLIMB QUICKLY WITH SUNNY
CONDITIONS EARLY ON ESPECIALLY OUT WEST. THEN THEY ARE LIKELY TO
FALL AS RAIN DEVELOPS.
TONIGHT...UPPER TROUGH CONTINUES TO TRACK WESTWARD. CONVECTION TO
WANE INLAND AS STABILIZATION OCCURS WITH WESTERN AREAS SEEING SOME
RAIN LINGER PASS SUNSET. CONVECTION TO REFIRE OVERNIGHT OFFSHORE AS
THE UPPER TROUGH AXIS NEARS THE COAST AND NOCTURNAL DESTABILIZATION
OCCURS. SOME SHOWERS TO WORK THEIR WAY INLAND ACROSS THE LOWER
VALLEY AS THE SURFACE TROUGH NEARS THE COAST.
SUNDAY...ANOTHER GOOD CHANCE OF SHOWERS AND THUNDERSTORMS AS THE
UPPER TROUGH AXIS MOVES OVERHEAD. SOUTH TEXAS WILL BE ON THE
NORTHERN PERIPHERY OF THE TROUGH WITH BETTER CONVERGENCE AND
INSTABILITY SHIFTING FARTHER TO THE SOUTH WITH THE CENTER OF THE
TROUGH. IN ANY CASE...MOISTURE VALUES AND DEEP EASTERLY TO KEEP RAIN
CHANCES RATHER HIGH CONSIDERING THE LAST TWO WEEKS. FORECAST REMAINS
IN RANGE OF MAV/GFS GUIDANCE WITH MET/NAM LOOKING TO HIGH WITH A
MORE ROBUST SURFACE DEVELOPMENT WHICH DOES ON LOOK REASONABLE.
DAYTIME DESTABILIZATION TO TAKE PLACE BUT COULD BE LIMITED WITH
MULTI LAYERED CLOUD COVER LIMITED SURFACE HEATING. WITH THIS SAID
TEMPERATURES TO BE 7 TO 10 DEGREES COOLER THEN THE EXTREME HEAT THAT
WE HAVE EXPERIENCED.
LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...BY SUNDAY NIGHT THE
INVERTED TROUGH AXIS WILL BE TO THE WEST OF THE VALLEY. MOISTURE
WILL STILL BE SUBSTANTIAL...WITH PW VALUES BEGINNING THE PERIOD AT
2 INCHES...SLOWLY FALLING TO 1.6 BY TUESDAY MORNING. WITH THE
ABUNDANCE OF MOISTURE STILL PRESENT...STILL FEEL THAT SEABREEZE
SHOWERS WILL SPARK DURING THE AFTERNOON MONDAY...ALBEIT NOT AS
WIDESPREAD AS OVER THE WEEKEND. H5 RIDGE REBUILDS ACROSS TEXAS IN
THE WAKE OF THE TROUGH ON TUESDAY...WITH PW VALUES AOB 1.5 INCHES
THROUGH THE REST OF THE WEEK. THIS PRECLUDES THE CHANCE OF ANY
SEABREEZE ACTIVITY. TEMPERATURES WILL START TO RECOVER ON
MONDAY...JUMPING BACK INTO THE UPPER 90S AND LOW 100S. A GRADUAL
RETURN TO WIDESPREAD 100 DEGREE TEMPERATURES WILL CONTINUE THROUGH
THE REST OF THE WEEK.
MARINE...
NOW THROUGH SUNDAY...THE APPROACH OF THE UPPER TROUGH AND A
SURFACE TROUGH TO KEEP AN EAST WIND AT LIGHT TO MODERATE LEVELS
TODAY THROUGH SUNDAY. SHOWERS AND THUNDERSTORMS TO INCREASE IN
COVERAGE AND INTENSITY THROUGH THE PERIOD PRODUCING A SLIGHTLY
HIGHER SEA TONIGHT AND SUNDAY. NO SMALL CRAFT ADVISORIES ARE
ANTICIPATED.
MONDAY NIGHT THROUGH THURSDAY...WEAK GRADIENT WILL BE THE RULE
ACROSS THE MARINE ZONES THROUGH THE WEEK...WITH ONSHORE FLOW OF 10
TO 15 KNOTS EXPECTED EACH DAY. SEAS WILL GENERALLY RUN 2 TO 4
FEET...APPROACHING 5 FEET INITIALLY MONDAY NIGHT INTO TUESDAY. NO
ADVISORIES ARE EXPECTED.
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
68/67
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
622 AM CDT SAT AUG 10 2013
.DISCUSSION...
SEE AVIATION FOR 12Z TAF DISCUSSION
&&
.AVIATION...
SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE COASTAL WATERS HAVE
REACHED THE COAST AND ARE BEGINNING TO PUSH INLAND ACROSS
SOUTHEAST TEXAS. THIS ACTIVITY WILL AFFECT MOST SITES BEFORE
DISSIPATING LATE THIS AFTERNOON. EXPECT A SIMILAR SITUATION ON
SUNDAY AS ANOTHER WEAK DISTURBANCE MOVES ACROSS THE COASTAL
WATERS. 38
&&
.PREV DISCUSSION... /ISSUED 420 AM CDT SAT AUG 10 2013/
DISCUSSION...
COASTAL RADARS SHOW SCATTERED SHOWERS AND THUNDERSTORMS IN THE
GULF WATERS THIS MORNING. AIRMASS ALONG THE COAST AND IN THE NW
GULF HAS BECOME VERY MOIST WITH GOES SOUNDER PRECIP WATER IMAGERY
SHOWING 2-2.2 INCHES WHERE CONVECTION IS ONGOING. WATER VAPOR
IMAGERY SHOWS UPPER LOW IN THE EAST CENTRAL GULF WHICH WILL
CONTINUE TO MOVE WEST ACROSS THE GULF AND DRIVE DEEPER MOISTURE
INLAND TODAY. UPPER LEVEL RIDGE HAS WEAKENED SOME BUT STRETCHES
ACROSS TEXAS THROUGH THE SE US. THINK SUBSIDENCE FROM THE RIDGE
MAY HOLD OFF CONVECTION INLAND FOR A LITTLE WHILE THIS MORNING BUT
DAY TIME HEATING WILL BE TOO MUCH FOR SCATTERED SHOWERS AND
THUNDERSTORMS NOT TO FORM. THE 06Z HRRR SHOWS CONVECTIVE
DEVELOPMENT ALONG THE COAST MAINLY 14-18Z AND THEN SCATTERED
ACTIVITY FURTHER INLAND FROM 18-21Z. THINK POPS OF 40 ALONG THE
COAST TRIMMING TO 20 FAR INLAND LOOKS ON TRACK. MIGHT BE ENOUGH
ACTIVITY TO BRING 50 POPS INLAND ALONG THE COAST BUT WILL HOLD OFF
TO SEE WHAT KIND OF COVERAGE DEVELOPS THROUGH THE MORNING.
CONVECTION FOR SUNDAY COULD BE ABOUT THE SAME COVERAGE AS TODAY
BUT PERHAPS A LITTLE LESS. MOISTURE WILL NOT BE AS HIGH WITH
PRECIP WATER AROUND 1.9-2 INCHES INSTEAD OF 2.2 INCHES.
NAM/GFS/ECMWF ARE ALL IN PRETTY GOOD AGREEMENT WITH THE CENTER OF
THE UPPER LOW TRACKING TOWARDS THE RIO GRANDE VALLEY ON SUNDAY.
VORTICITY WITH THE SYSTEM ALSO WEAKENS AND SHEARS OUT AS IT MOVES
INLAND. STILL THINK 30/40 POPS LOOK ON TRACK WITH 20 POPS FOR MORE
INLAND AREAS. BUT IF NAM IS MORE RIGHT...COULD HAVE MORE ACTIVITY
ON SUNDAY THAN TODAY. THINK THE NAM IS OVERDOING THE CONVECTION ON
SUNDAY AS UPPER LEVEL SUPPORT WILL NOT BE AS FAVORABLE.
THINK RAIN CHANCES WILL BE LESS ON MONDAY WITH 20 POPS IN PLACE.
THERE IS STILL DECENT MOISTURE WITH PRECIP WATER OF 1.9 INCHES BUT
THE RIDGE MAY BEGIN TO RE-ESTABLISH ITSELF OVER TX AT THIS TIME.
AGAIN LOOKS LIKE DAY TIME HEATING WILL BE THE MAIN TRIGGER FOR
CONVECTION BUT MOST LIKELY TIME WILL BE DURING THE AFTERNOON.
THE MAIN HAZARDS THE NEXT COUPLE OF DAYS WILL BE BRIEF HEAVY
RAINFALL AND LIGHTNING. COULD SEE SOME GUSTY WINDS BUT OVERALL NOT
A SEVERE THREAT. RAINFALL AMOUNTS THROUGH THE WEEKEND WILL LIKELY
BE AROUND A QUARTER TO HALF INCH WITH ISOLATED 1 INCH AMOUNTS IN
STRONGER STORMS. RAINFALL WILL PROVIDE SOME AREAS WITH A LITTLE
BREAK IN THE DROUGHT BUT NO REAL RELIEF. THEN AGAIN THERE COULD BE
SOME AREAS THAT DO NOT PICK UP ANY RAINFALL FROM THIS ENVIRONMENT.
NONETHELESS THE CLOUD COVER SHOULD HELP KEEP TEMPS LOWER AND AS A
RESULT WILL NOT NEED A HEAT ADVISORY FOR TODAY. WE WILL BE BACK TO
NEEDING 2 CONSECUTIVE DAYS OF A 108F HEAT INDEX TO ISSUE AN
ADVISORY.
THERE DOES LOOK TO BE A PATTERN CHANGE FOR THE EXTENDED FORECAST.
UPPER LEVEL RIDGE SHOULD BUILD OVER TX TUE/WED BUT THEN BECOMES
MORE ESTABLISHED OVER THE S ROCKIES BY THUR. TROUGHING OVER THE
GREAT LAKES WILL STRETCH TOWARDS THE MISS RIVER VALLEY SO NW FLOW
ALOFT MAY SUPPORT A FRONT PUSHING INTO THE AREA. GFS/ECMWF ARE
SHOWING A STRONGER FRONT MOVING INTO THE AREA THUR/FRI NEXT WEEK
SO WILL KEEP SOME RAIN CHANCES IN THE FORECAST ASSOCIATED WITH THE
FRONT. DRIER AIR MAY KNOCK MIN/MAX TEMPS DOWN A COUPLE OF DEGREES.
MODELS AGREE WITH AMPLIFYING THE PATTERN NEXT WEEKEND SO THIS
PATTERN MAY PERSIST A BIT LONGER AND GIVE SE TX A DECENT BREAK
FROM THE HEAT.
39
MARINE...
SCATTERED SHOWERS ONGOING ACROSS THE COASTAL WATERS THIS MORNING
AS A WEAK EASTERLY WAVE APPROACHES THE REGION. THIS FEATURE AND
ANOTHER DISTURBANCE EXPECTED ON SUNDAY WILL KEEP SCATTERED SHOWERS
AND THUNDERSTORMS ACROSS THE MARINE ZONES THROUGH THE WEEKEND. 38
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 99 78 97 75 97 / 20 20 20 20 20
HOUSTON (IAH) 95 78 95 77 95 / 40 20 40 20 20
GALVESTON (GLS) 90 82 90 81 91 / 40 20 40 20 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...39
AVIATION/MARINE...38
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
754 AM EDT SAT AUG 10 2013
.SYNOPSIS...
UNSETTLED PATTERN TO CONTINUE THROUGH THE WEEKEND AS FRONT STAYS
SITUATED ACROSS THE MID ATLANTIC INTO THE MID MISSISSIPPI VALLEY.
THE FRONT WEAKENS MONDAY WITH ANOTHER FRONT SHIFTING ACROSS OUR
REGION TUESDAY. HIGH PRESSURE WILL BUILD ACROSS TO OUR NORTH MID
TO LATE NEXT WEEK BUT ENOUGH MOISTURE SITUATED ACROSS THE
SOUTHEAST WILL KEEP THE THREAT OF SHOWERS AND STORMS AROUND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 330 AM EDT SATURDAY...
UPPER TROUGH ACROSS THE GREAT LAKES AND MID MS VALLEY EXPECTED TO
TRACK EAST WITH MID LEVEL SHORTWAVES MOVING ACROSS WHILE A FRONT
SLOWLY SAGS SOUTHWARD INTO OUR AREA BY SUNDAY. FOR THIS MORNING WE
ARE SEEING SOME HEAVY RAIN SHOWERS/EMBEDDED THUNDER ACROSS THE FAR
SW VA CORRIDOR INTO PORTIONS OF NW NC. THIS IN ASSOCIATION WITH SFC
THETA-E CONVERGENCE ALONG WITH PREFRONTAL TROUGH. THE LATEST RAP/RUC
SHOWING THAT ACTIVITY SWINGS EAST THROUGH DAWN INTO THE PIEDMONT
ALTHOUGH SOME WEAKENING IN THE NEW RIVER VALLEY APPEARS TO LIMIT
WHAT THE RAP SHOWS. FURTHER UPSTREAM CONVECTION ACROSS KY/WV SHOULD
SETTLE TOWARD THE SOUTHEAST WV AREA BY DAWN AS WELL.
THE FORECAST AND MODELS THE LAST FEW DAYS ADVERTISED HIGH POPS WHICH
HAS NOT WORKED OUT AT TIMES BUT WITH IMPROVING LOW LVL CONVERGENCE
AND PROXIMITY OF UPPER SHORTWAVE AM HESITANT TO KEEP POPS LOW
TODAY. I LEANED TOWARD THE RAP THIS MORNING BUT TRANSITIONED
TOWARD THE GFS THIS AFTERNOON BLENDED WITH THE PREVIOUS FORECAST.
AM THINKING THE CORRIDOR ALONG I-64 EAST INTO THE SHENANDOAH
VALLEY WILL BE ACTIVE LATE THIS MORNING INTO EARLY AFTERNOON WITH
DENSITY OF STORMS SHIFTING CONVECTION WITH OUTFLOW SOUTHEAST INTO
THE FOOTHILLS AND PIEDMONT THIS AFTERNOON. SO FOR NOW WILL HAVE
INCREASING POPS IN THE NORTH GOING TOWARD LIKELY BY MIDDAY THEN
SHIFTING HIGHER POPS SWD THRU THE AFTERNOON. NOT GOING TO PLAY
WITH 30 VS 50-60 POPS AS AIRMASS SOUPY ENOUGH AND PLENTY OF LIFT
WITH SOME UPPER SUPPORT THE HIGHER POPS AREA WIDE.
AGAIN...THINNING OUT OF CLOUDS SHOULD ALLOW SOME SUN TO HEAT
THINGS UP ALTHOUGH JUST GOING TO BE ENOUGH CLOUD COVER ALL DAY TO
PREVENT THE TEMPS FROM WARMING TOO HIGH UNLIKE WHAT HAPPENED
FRIDAY. WENT MORE TOWARD MET MOS EAST WHICH HAS NEAR 90 WHICH IS
BETWEEN THE COOLER ECMWF AND WARMER MAV. WITH CONVECTION AND
CLOUDS MORE PREVALENT OVER THE NORTHWEST WENT THE COOLER
MET...WITH UPPER 70S TO LOWER 80S.
THOUGH HEAVY RAIN THREAT REMAINS...THE ISOLATED FLASH FLOOD THREAT
REMAINS THAT A WATCH IS NOT NEEDED YET...BUT WILL HAVE TO SEE HOW
STORMS LINE UP THIS AFTERNOON TO SEE IF WE NEED ONE. THERE IS ALSO A
SMALL RISK OF SVR STORMS WITH THE SRN BELT OF WESTERLIES ALLOWING
FOR SOME WIND THREAT.
SHOULD SEE SOME COVERAGE ENTERING TONIGHT AS MODELS KEEP SHORTWAVE
ENERGY MOVING FROM WV/KY INTO NRN VA. MODELS ARE SHOWING MORE
AGREEMENT IN HAVING BEST CHANCE WEST AND AND NORTH...ALTHOUGH SOME
SHIFT IT SOUTH INTO THE NC/VA BORDER AREA AS WEAK LOW MOVES ACROSS.
AT THIS TIME HAVE LIKELY POPS IN THE EARLY EVENING TAPERING TO 40-50
BY MIDNIGHT...WITH NO FOCUSED AREA FOR HIGHER OR LOWER POPS...AS
LOSS OF HEATING EXPECTED TO RESULT IN MORE SCATTERED COVERAGE.
STILL MUGGY WITH DRIER AIR WELL NORTH ACROSS WRN PA/NY INTO THE
GREAT LAKES STATES. LOWS WILL RANGE FROM THE MID TO UPPER 60S ACROSS
THE WEST TO AROUND 70 AT ROANOKE AND POINTS EAST.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
AS OF 320 AM EDT SATURDAY...
THE AREA WILL CONTINUE WITHIN A PROGRESSIVE REGIME WITH DISTINCT
BOUTS OF HEAVY SHOWER AND THUNDERSTORM CHANCES. THE FIRST OF THESE
WILL BE DURING THE DAY SUNDAY WHEN A COLD FRONT PASSES THROUGH THE
REGION. MOST OF THE ACTIVITY WILL HEAD SOUTH OF THE AREA BY SUNDAY
EVENING. SURFACE HIGH PRESSURE BUILDS IN BEHIND THE FRONT BRIEFLY BY
MONDAY MORNING. HOWEVER...THE AXIS OF THIS HIGH/RIDGE WILL SHIFT
EAST OF THE AREA BY MONDAY MORNING...AND THUS ALLOW FOR SOUTHEAST
LOW LEVEL FLOW TO BRING LINGERING MOISTURE BACK INTO THE SOUTHWEST
PARTS OF THE FORECAST AREA. REGIONS ALONG THE CREST OF THE BLUE
RIDGE FROM ROUGHLY FLOYD VA SOUTHWEST INTO THE NORTHERN MOUNTAINS OF
NC WILL HAVE THE GREATEST POTENTIAL FOR SHOWERS AND A FEW
THUNDERSTORMS ON MONDAY.
BY MONDAY EVENING...THERE WILL BE A DECREASE IN COVERAGE OF THE
PRECIPITATION WILL THE LOSS OF DAYTIME HEATING. HOWEVER...OUR NEXT
APPROACHING COLD FRONT WILL START TO ALLOW FOR A RETURN OF ISOLATED
TO SCATTERED SHOWERS ACROSS THE FAR WESTERN PARTS OF THE REGION BY
SUNRISE TUESDAY. DURING THE DAY TUESDAY THIS FRONT WILL CROSS THE
AREA WITH A GOOD COVERAGE OF SHOWERS AND STORMS. SHOWERS ARE LIKELY
WITH SCATTERED THUNDERSTORMS ALONG AND EAST OF THE CREST OF THE BLUE
RIDGE BY TUESDAY AFTERNOON. TUESDAY NIGHT THERE WILL BE A GRADUAL
DECREASE IN COVERAGE ACROSS THE AREA.
TEMPERATURES THROUGH THE PERIOD WILL EXPERIENCE LITTLE VARIATION
SUNDAY THROUGH TUESDAY. IT WILL NOT BE UNTIL TUESDAY NIGHT HEADING
INTO EARLY WEDNESDAY THAT A CHANGE TOWARD A SLIGHTLY DRIER...AND
THUS COOLER...AIRMASS TAKES PLACE.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 130 PM EDT FRIDAY...
LITTLE CHANGE IN THE LONG WAVE 500 MB PATTERN THROUGHOUT THIS TIME
PERIOD... WITH A RIDGE OVER THE WESTERN UNITED STATES AND TROUGHING
OVER THE EAST. MODELS NOT SHOWING GOOD TRENDS ON HOW AMPLIFIED
EASTERN TROF WILL BE.
MAIN SHORT WAVE ENERGY STAYS NORTH OF THE FORECAST AREA...BUT
WEAKER SHORT WAVES AROUND THE SOUTHERN EDGE OF THE TROF...ALONG
WITH LOW LEVEL CONVERGENCE ALONG ANY BOUNDARIES WILL PROVIDE
ENOUGH LIFT FOR THE RELATIVELY WET PATTERN TO CONTINUE.
WILL HAVE HIGHEST PROBABILITY OF PRECIPITATION IN THE AFTERNOON
AND EVENING ON THURSDAY AND FRIDAY WHEN SURFACE HIGH PRESSURE
MOVES OFFSHORE AND RETURN FLOW AROUND THE HIGH BRINGS MOISTURE
BACK INTO THE CENTRAL AND SOUTHERN APPALACHIANS.
TEMPERATURES BEHIND THE FRONT ON TUESDAY NIGHT THROUGH WEDNESDAY
NIGHT WILL BE BELOW NORMAL...BUT HOW COOL THEY GET WILL DEPEND ON
THE AMPLITUDE OF THE TROF AND HOW FAR 850 MB FRONT ADVANCES SOUTH OF
THE FORECAST AREA.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 745 AM EDT SATURDAY...
SHOWERS MOVING INTO THE LWB-BLF CORRIDOR THIS MORNING MAY BRING
VSBYS/CIGS DOWN TO IFR OR LOWER BEFORE THE MIXING KICKS IN AND
CIGS RISE. AT THE MOMENT THE MODELS HAVE THE PRECIP AROUND THROUGH
MOST OF THE DAY AT BLF/LWB WITH PERIODS OF MODERATE TO HEAVY RAIN.
FOR NOW I AM HESITANT TO GO TO LOW ON VSBYS/CIGS AND HAVE -SHRA
AND VCTS.
FURTHER EAST WE WILL SEE SHOWERS AND STORMS FIRE UP IN THE 15-19Z
TIME FRAME WITH DANVILLE LAST TO SEE SHOWERS. AS WITH ANY STORM
HEAVY RAIN WILL BRING SOME IFR CIGS/VSBYS BUT EXPECT THAT VFR WILL
BE THE RULE MOST OF THE TIME.
TONIGHT...THE MODELS KEEP THE THREAT OF SHOWERS AROUND OVER THE
ENITRE CWA ESPECIALL ALONG AND SOUTH FROM BLF-BCB-DAN.
EXTENDED DISCUSSION...THE FRONT SHIFTS SLOWLY SOUTHEAST THRU THE
WEEKEND AND KEEPS THE THREAT OF SHOWERS/STORMS AROUND. THE FRONT
MAY SLIP SOUTH OF THE AREA BY MONDAY...BUT RETURN NORTH AS A WARM
FRONT BY TUESDAY AS ANOTHER FRONT/TROUGH APPROACH FROM THE NW.
POTENTIAL FOR SHRA/TSRA ANY DAY AT DAN...POSSIBLY A BREAK
LWB/BLF/BCB MON...BUT RETURNING BY TUE TO ALL AREAS.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/WP
NEAR TERM...WP
SHORT TERM...DS
LONG TERM...AMS
AVIATION...WP
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
207 PM PDT SAT AUG 10 2013
.DISCUSSION...AS OF 2:06 PM PDT SATURDAY...AN UPPER LOW OFF THE
NORTHERN CA COASTLINE CONTINUES TO DOMINATE THE WEATHER
PATTERN...WITH MODERATE ONSHORE FLOW AND BELOW SEASONABLE NORMAL
TEMPERATURES. THIS AFTERNOON...TEMPERATURES ROSE INTO THE 60S
ALONG THE COAST...TO THE 70S INLAND. ONE OF THE WARMEST SPOTS OF
THE DAY WAS PINNACLES NATIONAL PARK...AT 87 DEGREES. TEMPERATURES
ARE FORECAST TO RISE ANOTHER FEW DEGREES BEFORE SUNSET. THESE
TEMPERATURES ARE BETWEEN 5 AND 10 DEGREES BELOW NORMAL FOR THE
MIDDLE OF AUGUST.
THE MARINE LAYER...CURRENTLY AROUND 1500 FEET...IS FORECAST TO
DEEPEN TO AROUND 2000 FEET AGAIN OVERNIGHT...WITH ABUNDANT STRATUS
INLAND. PATCHY COASTAL DRIZZLE IS ALSO POSSIBLE AGAIN
OVERNIGHT...AS BOTH THE NAM AND HRRR INDICATE MANY AREAS OF 0.01"
OF ACCUMULATION LATE TONIGHT/EARLY SUNDAY MORNING. TEMPERATURES
ARE FORECAST TO FALL INTO THE 50S OVERNIGHT...SIMILAR TO THOSE
OBSERVED LAST NIGHT.
A SUBTLE WARMING TREND IS FORECAST TO TAKE PLACE TOMORROW THROUGH
AT LEAST THE MIDDLE OF NEXT WEEK...AS THE UPPER LOW SHIFTS SLOWLY
NORTH WITH UPPER LEVEL HIGH PRESSURE OVER THE SOUTHWEST US NUDGING
NORTHWEST INTO THE AREA. 850 MB TEMPERATURES ARE FORECAST TO RISE
BETWEEN 1 AND 2 DEGREES C BETWEEN THIS AFTERNOON AND SUNDAY
AFTERNOON...RESULTING IN INLAND TEMPERATURES WARMING INTO THE MID
70S TO MID 80S. IN FACT...SOUTHERN MONTEREY AND SAN BENITO
COUNTIES ARE FORECAST TO REACH THE MID 90S.
THE MARINE LAYER WILL ALSO COMPRESS BEGINNING SUNDAY NIGHT AND
CONTINUING OVER THE NEXT FEW DAYS...AIDING IN THE WARMING TREND.
BY WEDNESDAY...TEMPERATURES INLAND WILL RISE INTO THE UPPER 70S TO
UPPER 80S...NEAR NORMAL FOR THE MIDDLE OF AUGUST.
ON A SIDE NOTE...THE CLIMATE PREDICTION CENTER 8 TO 14 DAY OUTLOOK
(VALID FROM AUGUST 18TH THROUGH AUGUST 24TH) CALL FOR SLIGHTLY
ABOVE NORMAL TEMPERATURES...MAINLY FOR THE INLAND LOCATIONS.
&&
.AVIATION...AS OF 11:21 AM PDT SATURDAY...AN UPPER LEVEL LOW
PRESSURE SYSTEM THAT HAS AFFECTED OUR REGION OVER THE LAST FEW
DAYS HAS SHIFTED TO OUR NORTH AS A RIDGE OF HIGH PRESSURE
ORIGINATED IN THE DESERT SOUTHWEST BEGINS TO BUILD INTO
CALIFORNIA. STRATUS IS EXPECTED TO CLEAR BY EARLY THIS AFTERNOON
FOR ALL TERMINALS. GENERALLY LIGHT WINDS ARE EXPECTED FOR THE
MAJORITY OF THE FORECAST REGION THROUGHOUT THE DAY. STRATUS IS
EXPECTED TO RETURN BY THIS EVENING. ALL TERMINALS ARE EXPECTED TO
HAVE LOW CEILINGS BY LATE THIS EVENING AND INTO THE MORNING HOURS.
PATCHY DRIZZLE IS LIKELY. CLEARING TIMES TOMORROW WILL BE SIMILAR
TO TODAY.
VICINITY OF KSFO...MVFR CONDITIONS ARE EXPECTED TO IMPROVE TO VFR
CONDITIONS BY MID-DAY. WIND SPEEDS WILL INCREASE TO 15KT
AND GUSTS TO 20KT BY THIS AFTERNOON. CONDITIONS ARE FORECAST TO
DIMINISH TO MVFR BY LATE THIS EVENING AS THE STRATUS RETURNS.
CONDITIONS ARE EXPECTED TO IMPROVE TO VFR TOMORROW AT AROUND THE
SAME TIME AS TODAY...IF NOT SLIGHTLY EARLIER.
KSFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY AREA TERMINALS...MVFR CONDITIONS AT THE MONTEREY
TERMINAL ARE EXPECTED TO IMPROVE TO VFR BY MID-DAY. BOTH
TERMINALS ARE FORECAST TO HAVE LIGHT WINDS AND VFR CONDITIONS THROUGH
THE DAY THAT WILL LAST INTO THE EARLY EVENING WHEN CONDITIONS ARE
EXPECTED TO DIMINISH TO MVFR. CONDITIONS WILL FURTHER DEGRADE TO
VFR OVERNIGHT IN THE EARLY MORNING HOURS WITH DRIZZLE LIKELY NEAR
THE COAST.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TNGT...NONE.
$$
PUBLIC FORECAST: RILEY
AVIATION/MARINE: SIERRA/SIMS
VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO
FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.SANFRANCISCOBAYAREA.GOV
WWW.TWITTER.COM/NWSBAYAREA
WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1126 AM MDT SAT AUG 10 2013
.UPDATE...
ISSUED AT 1052 AM MDT SAT AUG 10 2013
STILL A THREAT FOR SOME LOCALLY HEAVY RAIN THIS AFTERNOON AND
EVENING. LOW CLOUDS ALONG PORTIONS OF THE INTERSTATE 25 CORRIDOR
HAVE DELAYED SURFACE HEATING. MESONET OBSERVATIONS SUGGEST SOME
DRIER MID LEVEL AIR IS OVER THE EASTERN MOUNTAINS OF
COLORADO...BUT BELIEVE SOME MOISTURE MAY ADVECT INTO THE REGION
FROM THE SOUTH THIS AFTERNOON. SHORTWAVE APPEARS TO BE MOVING INTO
SOUTHWEST COLORADO AND IS CONTINUING TO MOVE NORTHEAST. WITH THE
LESS HEATING AND SHORTWAVE OVER EXTREME SOUTHWEST
COLORADO...BELIEVE CONVECTION OVER EASTERN MOUNTAINS WILL BE
DELAYED. HRRR AND LOCAL WRF SUGGEST CONVECTION WILL DEVELOP OVER
THE EASTERN MOUNTAINS...INCLUDING WALDO CANYON REGION...AROUND 3
TO 4 PM TODAY. GIVEN VERY MOIST SOIL CONDITIONS AND POTENTIAL FOR
LOCALLY HEAVY DOWNPOURS...WILL CONTINUE FLASH FLOOD WATCH. WATCH
MAY START TOO EARLY...BUT WILL LEAVE IT ALONE TO AVOID ANY
CONFUSION. SHORTWAVE MOVING INTO WESTERN COLORADO WILL DEVELOP
CONVECTION AROUND WEST FORK COMPLEX AROUND 2 PM.
.UPDATE ISSUED AT 737 AM MDT SAT AUG 10 2013
UPDATED SHORT TERM FORECASTS TO REFLECT CURRENT CONDITIONS. LW
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 555 AM MDT SAT AUG 10 2013
...ANOTHER ROUND OF STORMS TODAY WITH HEAVY RAIN POTENTIAL...
PATTERN TODAY SHAPING UP VERY SIMILAR TO YESTERDAY. AN ACTIVE
DISTURBANCE VISIBLE IN SATELLITE PICTURES OVER NEW MEXICO THIS
MORNING IS POISED TO WORK ITS WAY NORTHWARD INTO WESTERN COLORADO
LATER THIS MORNING...AND THEN EASTWARD ACROSS THE PIKES PEAK REGION
IN THE AFTERNOON. HI RES MODELS SHOW ANOTHER ROUND OF CONVECTION
DEVELOPING OVER TELLER AND EL PASO COUNTIES BETWEEN APPROXIMATELY 3
AND 6 PM. GIVEN THIS INFORMATION...AND THE FACT THAT THE SOILS ON
THE WALDO ARE CURRENTLY SATURATED AND UNSTABLE FROM THE HEAVY RAIN
THAT FELL YESTERDAY...WE WILL POST A FLASH FLOOD WATCH FOR THE WALDO
CANYON BURN SCAR AREA FROM NOON UNTIL 9 PM MDT TODAY.
SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER MOST OF THE
AREA AGAIN THIS AFTERNOON AND EVENING. AGAIN...THE MONSOON REMAINS
ACTIVE WITH THE PLUME SENDING DISTURBANCES OUR WAY. IN ADDITION...
THE LOWER LEVELS OF THE ATMOSPHERE CONTAIN PLENTY OF MOISTURE TO
WORK WITH...WITH SURFACE DEWPOINTS AROUND THE AREA WIDESPREAD IN THE
50S ACROSS THE PLAINS...AND MOSTLY IN THE 40S IN THE HIGH COUNTRY.
SO...ONCE AGAIN TODAY...THE PRIMARY WEATHER CONCERN WILL BE LOCALLY
HEAVY RAIN...WITH THE POTENTIAL FOR FLASH FLOODING...ESPECIALLY IN
AND NEAR AREA BURN SCARS...MOST NOTABLY INCLUDING THE WALDO CANYON
BURN SCAR WHERE IT RAINED SO HARD YESTERDAY AND THE SOILS ARE
ALREADY SATURATED AND UNSTABLE.
HIGH WATER LEVELS ARE OCCURRING IN MANY PARTS OF SOUTHERN COLORADO
AT THIS TIME. MANY EPHEMERAL STREAMS...OR STREAMS THAT TYPICALLY
ONLY FLOW BRIEFLY DURING AND FOLLOWING A PERIOD OF RAINFALL...ARE
CURRENTLY RUNNING FULL. MANY SMALL STREAMS AND ARROYOS HAVE SEEN
HIGH WATER OR FLOODING IN RECENT DAYS. A NUMBER OF SMALLER EARTHEN
DAMS AND AGRICULTURAL DIVERSIONS ARE SEEING STRESS THAT THEY HAVEN`T
SEEN FOR A WHILE. THE PAST SEVERAL DAYS OF THE MONSOON HAVE BEEN
RATHER EXCEPTIONAL BY SOUTHERN COLORADO STANDARDS...WITH NUMEROUS
REPORTS OF FLOODING COMING IN FROM ALL AREAS...BOTH URBAN AND RURAL.
ADDITIONAL RAINS COMING IN THE DAYS AHEAD WILL ONLY EXACERBATE THE
SITUATION. IF YOU HAVEN`T ALREADY DONE SO...NOW IS A GOOD TIME TO
MAKE PREPARATIONS FOR HIGH WATER AND FLOODING. WHAT WOULD YOU DO
IF WATER WAS SUDDENLY SURROUNDING YOUR HOUSE OR VEHICLE? THINK
ABOUT IT NOW...SO YOU KNOW WHAT TO DO THEN.
OTHER POTENTIAL WEATHER HAZARDS WITH STORMS TODAY WILL INCLUDE
LIGHTNING...STRONG GUSTY WINDS TO AROUND 50 MPH...AND SMALL
HAIL. LW
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 555 AM MDT SAT AUG 10 2013
LONGER TERM METEOROLOGICAL CONDITIONS CONTINUE TO BE IMPACT
ADDITIONAL PRECIPITATION WILL HAVE ON AREA BURN SCARS(ESPECIALLY
THE WALDO CANYON BURN AND BLACK FOREST BURN SCARS)...TEMPERATURES
AND POPS.
WARMER AND SOMEWHAT DRIER CONDITIONS ARE STILL EXPECTED TO
DEVELOP OVER THE FORECAST DISTRICT FROM SUNDAY INTO EARLY MONDAY
WITH MODEL SOUNDING PRECIPITABLE WATER VALUES EXPECTED TO REMAIN
UNDER ONE INCH OVER AREAS SUCH AS THE I-25 CORRIDOR DURING THIS
TIME-FRAME.
AS MENTIONED IN PREVIOUS DISCUSSIONS...ALTHOUGH A SOMEWHAT DRIER
AIRMASS WILL BE LOCATED OVER SOUTHERN COLORADO...STILL ANTICIPATE
THAT ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS IN
COMBINATION WITH WARMER TEMPERATURES WILL BE NOTED OVER THE CWFA
FROM THIS WEEKEND INTO EARLY MONDAY AFTERNOON. PLEASE REMEMBER
THAT SOME OF THE STRONGER THUNDERSTORMS WILL BE CAPABLE OF
PRODUCING LOCALIZED HEAVY RAINFALL AS WELL AS POTENTIAL BURN SCAR
FLOODING ISSUES DURING THE PERIOD.
RECENT FORECAST MODEL SOUNDINGS AND COMPUTER SIMULATIONS CONTINUE
TO INDICATE THAT INCREASINGLY MOIST EASTERLY FLOW WILL ALLOW
PRECIPITABLE WATER VALUES TO EXCEED ONE INCH AT TIMES AGAIN OVER
PORTIONS OF THE EASTERN MOUNTAINS AND THE I-25 CORRIDOR(INCLUDING
THE WALDO CANYON AND NEARBY BURN SCARS)...ESPECIALLY DURING THE
AFTERNOON AND EVENING HOURS.
THIS WILL ALLOW FOR INCREASED POPS IN COMBINATION WITH NEAR
SEASONAL MID-AUGUST TEMPERATURES FROM LATER MONDAY INTO AT LEAST
WEDNESDAY. LOCALLY HEAVY RAINFALL WILL AGAIN BE POSSIBLE DURING
THIS TIME-FRAME AND ANOTHER ROUND OF BURN SCAR FLOODING ISSUES
WILL BE POSSIBLE DURING THIS PERIOD. WFO PUEBLO WILL CONTINUE TO
MONITOR CLOSELY.
LATEST LONGER TERM DATA STILL SUGGESTS THAT THE HIGHEST POTENTIAL
FOR LOCALIZED HEAVY RAIN NEXT WEEK SHOULD BE NOTED FROM LATER
MONDAY INTO WEDNESDAY BEFORE SOMEWHAT DRIER AND WARMER CONDITIONS
ATTEMPT TO DEVELOP OVER THE MAJORITY OF THE FORECAST DISTRICT FROM
THURSDAY INTO EARLY FRIDAY AFTERNOON IN ADVANCE OF NEXT RELATIVELY
MOIST NORTH-NORTHEASTERLY SURGE BY LATER FRIDAY/FRIDAY NIGHT.
FINALLY...LOW-GRADE GRADIENT WINDS ARE ANTICIPATED OVER THE
MAJORITY OF THE FORECAST DISTRICT FROM SUNDAY INTO NEXT FRIDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1052 AM MDT SAT AUG 10 2013
ANOTHER DAY WITH THE MONSOON PLUME OVER THE REGION AND SOME LOW
LEVEL MOISTURE ON THE PLAINS. THUNDERSTORMS WILL DEVELOP OVER THE
MOUNTAINS AND HIGH VALLEYS AROUND 19Z TO 20Z. CONVECTION IS
EXPECTED TO DEVELOP OVER PORTIONS OF THE EASTERN MOUNTAINS AROUND
21Z AND MOVE TO THE EAST. CONVECTION SHOULD END BY MID EVENING AS
A SHORTWAVE PASSES THROUGH THE REGION. LOWER LEVELS SHOULD BE DRIER
TONIGHT ON THE PLAINS AND DO NOT ANTICIPATE ANY LOW CLOUDS OR FOG
AT KCOS AND KPUB.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 9 PM MDT THIS EVENING FOR COZ081-084-085.
&&
$$
UPDATE...PGW
AVIATION...PGW
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
254 PM CDT SAT AUG 10 2013
.DISCUSSION...
341 AM CDT
MAIN FORECAST CONCERN IS SHRA/TSRA CHANCES SUNDAY THROUGH MONDAY
EVENING. EARLY MORNING W/V IMAGERY SHOWS BROAD TROUGHING FROM
EASTERN INTO CENTRAL CANADA AND THE NORTHERN LAKES WITH RIDGING
OVER THE WESTERN CONUS AND SEVERAL WAVES CRESTING THE RIDGE OVER
THE NORTHERN ROCKIES THAT WILL PLAY A ROLE IN OUR SENSIBLE WEATHER
ON SUNDAY AND SUNDAY NIGHT AS THEY TRAVERSE DISTURBED WEST-
NORTHWEST FLOW ALOFT. AT THE SURFACE...HIGH PRESSURE WILL CENTER
OVER THE REGION TODAY...BEFORE SLOWLY SLIDING EAST SUNDAY. A COLD
FRONT WILL MOVE THROUGH THE AREA ON MONDAY.
COOLER AIR MASS WILL FILTER INTO AREA TODAY...NOTED WITH +10 AND +11
RESPECTIVELY AT 850 MB AT KMPX AND KGRB ON THE 00Z RAOBS. THE BACK
EDGE OF CIRRUS SHIELD OVER THE AREA WILL CLEAR OFF TO THE EAST OF
BY DAYBREAK OR SO...YIELDING EARLY MORNING CLEAR SKIES...BUT
GUIDANCE SHOWS MOISTURE FROM H9-H8 SEEPING IN FROM NORTH DURING
DAY...WHICH SHOULD ALLOW FOR SCATTERED TO POSSIBLY BROKEN CUMULUS BY
THE AFTERNOON AS LOW LEVEL LAPSE RATES STEEPEN. PROGGED H8 AND H9
TEMPS SUPPORTS HIGHS IN THE UPPER 70S TO POSSIBLY AROUND 80 NORTH OF
I-80 AND LOWER 80S SOUTH...WITH A FEW MID 80S READINGS. THE
EXCEPTION WILL BE THE LAKEFRONT WITH SYNOPTIC ONSHORE FLOW AND HIGHS
ONLY IN THE LOWER AND MID 70S. ALL IN ALL...IT WILL BE A SPECTACULAR
START TO THE WEEKEND. HIGH PRESSURE OVERHEAD TONIGHT AND MAINLY
CLEAR SKIES WILL RESULT IN COOL CONDITIONS IN THE LOWER AND MID 50S
OUTSIDE OF THE CHICAGO HEAT ISLAND.
THE INITIAL LEAD WAVE CURRENTLY OVER WYOMING LOOKS TO BE APPROACHING
THE REGION BUT LIKELY FOCUS NEAR OR NORTH OF THE WISCONSIN BORDER.
BY EARLY SUNDAY...A CLUSTER OF SHRA/TSRA COULD TRAVERSE THE UPPER
MISSISSIPPI VALLEY BUT IT SHOULD WEAKEN FARTHER EAST DUE TO THE
INFLUENCE OF THE HIGH PRESSURE RIDGE...LIMITED ELEVATED INSTABILITY
AND VERY WEAK LAPSE RATES ALOFT. DESPITE SOME CONSENSUS IN THE
GUIDANCE ON TRACKING THIS FEATURE TOWARD SOUTHERN WISCONSIN...HAVE
GENERALLY MAINTAINED CHANCE POPS ALONG THE BORDER. THE EXTENT OF
CLOUD COVER WITH THIS WAVE COULD LIMIT TEMPERATURES A BIT MORE THAN
CURRENTLY DEPICTED TO THE NORTH...BUT TO THE SOUTH...WHERE LESS
CLOUD COVER IS ANTICIPATED....850/925 TEMPS WILL SUPPORT HIGHS
APPROACHING THE MID 80S. GIVEN THE FACTORS THAT WILL LIKELY LEAD TO
WEAKENING OF THE PRECIP SHIELD ASSOCIATED WITH THE MID-LEVEL
WAVE...IT STILL REMAINS POSSIBLE THAT MOST OF THE AREA COULD HAVE A
DRY SUNDAY.
STRENGTHENING LOW LEVEL FLOW WILL RESULT IN DECENT MOISTURE
TRANSPORT AND CONVERGENCE FOCUSED INTO THE NORTHERN THIRD OF CWA
SUNDAY NIGHT WITH ANOTHER MID-LEVEL FEATURE WELL AHEAD OF SURFACE
COLD FRONT THAT WILL BE APPROACHING SLOWLY FROM THE NORTHWEST. EXACT
TRACK OF MIDLEVEL WAVE AND STRENGTH OF 850-925 FLOW WILL NEED TO BE
RESOLVED...BUT HAVE BUMPED UP POPS TO HIGH CHANCE RANGE ALONG THE
WISCONSIN BORDER...TAPERING TO A DRY FORECAST IN THE FAR SOUTHERN
FORECAST SOUNDINGS SHOWING SOME ELEVATED INSTABILITY AND WARM
ADVECTION PATTERN MEANS THERE WILL LIKELY BE AT LEAST EMBEDDED
THUNDER. CLOUD COVER AND WARM ADVECTION WILL RESULT IN MILDER LOW
TEMPS.
THE CONVECTIVE EVOLUTION ON SUNDAY NIGHT INTO EARLY MONDAY WILL
DICTATE TO A LARGE EXTENT WHAT HAPPENS WITH CONVECTIVE CHANCES ON
MONDAY AHEAD OF A COLD FRONT. FAVOR A SLOWER FRONTAL PASSAGE DURING
THE AFTERNOON...BUT NOT QUITE AS SLOW AS LATEST NAM. ASSUMING CLOUD
COVER DOES NOT HINDER WARMING TOO MUCH...H85 TEMPS AROUND +15 WILL
YIELD HIGHS IN THE LOWER 80S NORTH AND MID 80S SOUTH...WITH
DEWPOINTS RETURNING TO THE MID TO UPPER 60S. THIS COULD YIELD ~1500
J/KG OF CAPE PER FORECAST SOUNDINGS...WITH DECENT CONVERGENCE FROM
THE SURFACE TO 850 MB FAVORING AT LEAST SCATTERED COVERAGE OF
THUNDERSTORMS...BUT DID NOT GO HIGHER THAN MID CHANCE POPS DUE TO
UNCERTAINTY OVER CONVECTIVE EVOLUTION. IF ENOUGH INSTABILITY
DEVELOPS...WILL NEED TO WATCH FOR A SEVERE THREAT PRIMARILY IN THE
FORM OF DAMAGING WINDS...AS NORTHWESTERLY FLOW ALOFT WILL INCREASE
TO 40 KT DURING THE DAY AND STEEP LOW LEVEL LAPSE RATES WILL DEVELOP
AS WELL. HIGH FREEZING LEVELS AND MEAGER LAPSE RATES ABOVE 600 MB
WOULD LIKELY LIMIT THE HAIL THREAT.
ANY REMAINING SHRA/TSRA SHOULD CLEAR THE SOUTHERN CWA DURING THE
EVENING...WITH HIGH PRESSURE BUILDING FROM UPPER MIDWEST BEHIND COLD
FRONT. COOL NORTHERLY FLOW FROM THE SURFACE UP TO THE MID LEVELS
THANKS TO UPPER TROUGHING OVER EASTERN CANADA WILL SET UP A BELOW
NORMAL...BUT PLEASANT TUESDAY THROUGH FRIDAY PERIOD. AFTER HIGHS
LIKELY ONLY IN THE MID 70S AWAY FROM THE LAKE TUES AND
WEDS...READINGS WILL WARM SOME BY FRIDAY AS HEIGHTS BEGIN TO RISE
AND THERMAL PROFILES SLOWLY WARM. THE LAKEFRONT WILL BE KEPT COOLER
EACH DAY BY PERSISTENT ONSHORE FLOW.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* WIND REMAINING PRIMARILY NORTHEAST THIS AFTERNOON...THOUGH WITH
SOME MINOR VARIABILITY FROM NNE TO ENE AT TIMES.
* VARIABILITY IN WIND DIRECTION ALSO POSSIBLE SUNDAY...THOUGH
SHOULD GO FROM LIGHT WEST TO A LIGHT EAST-SOUTHEAST LAKE BREEZE
BY LATE AFTERNOON.
* SOME POTENTIAL FOR -RA/SHRA SUNDAY AFTERNOON...THOUGH
PROBABILITY HIGHER WEST/NORTH OF ORD/MDW TERMINALS.
RATZER
//DISCUSSION...UPDATED 18Z...
SURFACE HIGH PRESSURE WAS CENTERED NEAR KDSM AT 17Z...AND WILL
CONTINUE TO SLOWLY DRIFT SOUTHEAST ACROSS THE MIDWEST THROUGH
SUNDAY. EAST OF THE HIGH CENTER ACROSS NORTHERN IL...WINDS WERE
GENERALLY LIGHT NORTHERLY...WITH A NORTHEAST COMPONENT OFF OF THE
LAKE ACROSS THE CHICAGO METRO TERMINALS. WIND DIRECTION HAS
BECOME SOMEWHAT VARIABLE ACROSS ORD/MDW AREAS AT MIDDAY...BUT
EXPECT LAKE BREEZE PUSH THIS AFTERNOON WILL REESTABLISH A MORE
SOLID EAST-SOUTHEAST SFC WIND. WEAK PRESSURE GRADIENT TONIGHT AS
SURFACE RIDGE MOVES ACROSS THE AREA WILL ALLOW LIGHT/VARIABLE OR
CALM WINDS TO DEVELOP BY LATE EVENING AND CONTINUE INTO EARLY
SUNDAY MORNING. THE HIGH CENTER SHOULD MOVE JUST OFF TO THE SOUTH
OF THE TERMINALS SUNDAY...WHICH SHOULD RESULT IN A WEST-NORTHWEST
WIND INITIALLY...THOUGH THE WEAK GRADIENT WILL LIKELY ALLOW FOR
SOME VARIABILITY ONCE AGAIN AND AN EAST-SOUTHEAST LAKE BREEZE IN
THE MID/LATE AFTERNOON HOURS.
SCATTERED TO BROKEN DECK OF DIURNAL CU OVER AREA WILL FADE WITH
SUNSET. FOCUS FOR ADDITIONAL CLOUD AND PRECIP DEVELOPMENT WILL
THEN FOCUS TO OUR NORTHWEST TONIGHT WITH A MID-LEVEL DISTURBANCE
MOVING INTO MINNESOTA AND NORTHERN IA. SHRA/TSRA ARE EXPECTED TO
DEVELOP ACROSS SOUTHERN MN AND MOVE SLOWLY EAST TOWARD THE IL/WI
BORDER REGION SUNDAY. AT THIS TIME IT APPEARS RFD WILL HAVE THE
BEST POTENTIAL FOR SOME SHRA BY MID-LATE MORNING. GRADUAL
WEAKENING IS EXPECTED FARTHER TO THE EAST DURING THE DAY...SO
HAVE HELD OFF FROM INTRODUCING PRECIP INTO ORD 24-30 HOUR SECTION
OF TAF WITH OVERALL LOW CONFIDENCE AT THIS TIME. HOWEVER WOULD
EXPECT THERE COULD BE SOME SHRA MAINLY NORTH/WEST OF ORD AT SOME
POINT SUNDAY AFTERNOON.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN PREVAILING WIND DIRECTION FROM THE NORTHEAST
THIS AFTERNOON.
* HIGH CONFIDENCE IN VFR CONDITIONS THROUGH SUNDAY MORNING.
* MEDIUM CONFIDENCE IN SHRA REMAINING NORTH/WEST OF ORD/MDW
THROUGH 18Z SUNDAY.
* MEDIUM-LOW CONFIDENCE IN LIGHT WIND DETAILS SUNDAY.
RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...CHANCE SHRA/TSRA.
MONDAY...CHANCE SHRA/TSRA. MVFR POSSIBLE.
TUESDAY THROUGH FRIDAY...DRY/VFR.
MDB
&&
.MARINE...
252 AM CDT
DEEPENING LOW PRESSURE IS MOVING EASTWARD ACROSS EASTERN QUEBEC THIS
MORNING. ONE AREA OF HIGH PRESSURE IS SPREAD ACROSS THE OHIO RIVER
VALLEY AND THE SOUTHEAST U.S. WHILE ANOTHER AREA OF HIGH PRESSURE IS
SPREAD FROM THE CANADIAN PRAIRIES TO THE CENTRAL PLAINS. THIS
NORTHERN HIGH WILL MOVE SOUTHEASTWARD AND ACROSS CENTRAL ILLINOIS
TONIGHT. A TROUGH OF LOW PRESSURE WILL THEN MOVE ACROSS THE AREA
EARLY MONDAY WITH STRONG CANADIAN HIGH PRESSURE BUILDING IN BEHIND
IT INTO TUESDAY. AS A RESULT...SOUTHERLY WINDS AHEAD OF THE FRONT
MONDAY WILL TURN NORTHERLY LATER MONDAY INTO TUESDAY AS LOW PRESSURE
BEGINS TO DEEPEN ACROSS NORTHERN NEW ENGLAND. EXPECT THAT WINDS WILL
COME UP TO AROUND 20 KT MONDAY NIGHT AND TUESDAY AS THE PRESSURE
GRADIENT TIGHTENS AND A PUSH OF COOLER AIR SPREADS IN. THIS WILL
KICK WAVES UP TO NEAR SMALL CRAFT ADVISORY CRITERIA BEFORE SUBSIDING
TUESDAY NIGHT OR WEDNESDAY MORNING. HIGH PRESSURE WILL THEN BE OVER
THE AREA WEDNESDAY THROUGH THE REST OF NEXT WEEK.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Lincoln IL
1258 PM CDT Sat Aug 10 2013
.DISCUSSION...
ISSUED 1035 AM CDT Sat Aug 10 2013
Mild weather in store for central Illinois through the weekend as
high pressure builds into the Midwest from the Plains. Warm and
sunny conditions expected with a few fair weather clouds possible
into the late morning and early afternoon hours. Going forecast
looks good. Have adjusted the high temperatures up a couple
degrees in the northern CWA to reflect a quicker warm up...as well
as a tweak to the hourly temperature forecast for the remainder of
the day. Adjustments are relatively slight and no updates to the
zone forecast are anticipated.
&&
.AVIATION...
ISSUED 1255 PM CDT Sat Aug 10 2013
Not much in the way of significant weather changes for the
aviation forecast. Light and variable winds...a few cu...and
repeat tomorrow. Overnight should be light and mostly northerly
winds with clearing for the region. The clearing is the only
question mark for the forecast with regards to potential for
fog/BR in the early morning. Not confident enough to add it to the
TAFs at this time...though guidance hints in that direction. Will
monitor this afternoons dewpoints and how much of that moisture
will mix out and erode in the boundary layer. As of now...VFR throughout.
HJS
&&
.PREV DISCUSSION...
ISSUED 240 AM CDT Sat Aug 10 2013
SHORT TERM...Today through Monday
Weak secondary cold front will continue to drop southward and
dissipate across central Illinois today, while main synoptic
boundary remains stalled from the Mid-Atlantic states W/SW into
the Southern Plains. Periods of showers and thunderstorms will
accompany the primary front, but will stay well south of the
KILX CWA. High-res HRRR hints at a few showers potentially
developing ahead of a weak short-wave across northern Indiana this
afternoon, but these would likely remain outside of central
Illinois as well. End result will be a partly to mostly sunny day
with high temperatures in the lower 80s.
High pressure will build southward into the region tonight, providing
cool/dry weather with lows dropping into the 50s. With high pressure
overhead, another pleasant summer day is in store for Sunday with
highs reaching the lower to middle 80s. Once the high begins to
slide off to the east, a light southerly return flow will allow a
warmer/more humid air mass to trickle back into the area Sunday
night into Monday. Forecast soundings indicate precipitable water
values climbing back over 1.50 inches while surface dewpoints
reach the 70-degree mark by Monday afternoon. Meanwhile...another
deep upper low will rotate southward from Hudson Bay, pushing a cold
front into Illinois. This front will interact with the increasingly
moist air mass to produce scattered showers and thunderstorms,
particularly during the afternoon and evening. Due to only modest
instability with CAPE values around 1500J/kg and best upper
support remaining further north across the Great Lakes, am not
expecting widespread convection. Will therefore maintain just
chance pops Monday into Monday night.
LONG TERM...Tuesday through Friday
Frontal boundary sags southward early next week, with model consensus
taking it south of the Ohio River by Tuesday morning. Will hold on
to just a slight chance POP across the far SE CWA into Tuesday in
case front slows. Otherwise, another cool/dry Canadian air mass
will settle southward into the region behind the departing front
for the remainder of next week. With upper flow becoming
prominently northwesterly, any potential MCS activity will likely
be shunted well W/SW of Illinois, leading to a dry forecast
through Friday. Temps next week will remain below normal, with
afternoon highs generally in the upper 70s/lower 80s and overnight
lows in the upper 50s/lower 60s.
Barnes
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
210 PM EDT SAT AUG 10 2013
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 339 AM EDT SAT AUG 10 2013
A SECONDARY COLD FRONT WILL TRAVERSE CENTRAL INDIANA
TODAY...BRINGING A SLIGHT CHANCE FOR SOME SCATTERED SHOWERS
THIS MORNING AND ISOLATED THUNDERSTORMS THIS AFTERNOON. HIGH
PRESSURE WILL RESULT IN DRY CONDITIONS FROM TONIGHT THROUGH
SUNDAY. HOWEVER...A WEAK SURFACE LOW WILL TRY TO ENTER CENTRAL
INDIANA FROM THE SOUTH ON MONDAY...FOLLOWED BY A STRONGER COLD
FRONT THAT NIGHT WHICH WILL BRING ADDITIONAL SHOWER AND
THUNDERSTORM CHANCES INTO TUESDAY MORNING.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 955 AM EDT SAT AUG 10 2013
MID AND HIGH LEVEL CLOUDS PERSISTING SO FAR THIS MORNING ACROSS
ALL BUT NORTHERN PORTIONS OF THE FORECAST AREA. A FEW LIGHT
SHOWERS CONTINUE TO GRAZE FAR SOUTHERN COUNTIES AS A WEAK WAVE
ALOFT PASSES THROUGH THE LOWER OHIO VALLEY. TEMPS WERE GENERALLY
IN THE LOWER AND MIDDLE 70S AS OF 13Z.
FORECAST IN GOOD SHAPE THIS MORNING WITH JUST MINOR CHANGES
NEEDED. WEAK SURFACE WAVE ALONG SECONDARY FRONT NOTED ACROSS
NORTHEAST INDIANA WITH THE BOUNDARY EXTENDING SOUTHWEST INTO
CENTRAL ILLINOIS. THE BOUNDARY WILL PROGRESS SLOWLY SOUTH ACROSS
THE FORECAST AREA THROUGH THE AFTERNOON AND EVENING. WHILE FORCING
ALOFT REMAINS VERY WEAK...PRESENCE OF LOW LEVEL MOISTURE AND WEAK
INSTABILITY AHEAD OF THE BOUNDARY WILL LIKELY BE ENOUGH TO
GENERATE ISOLATED CONVECTION THROUGH THE AFTERNOON AND EARLY
EVENING...ESPECIALLY OVER THE SOUTHEAST HALF OF THE FORECAST AREA.
CURRENT HRRR CAPTURES THIS IDEA WELL...HINTING AT BEST POTENTIAL
FOR CONVECTIVE DEVELOPMENT OVER EASTERN COUNTIES WHICH MAKES SENSE
WITH SLIGHTLY BETTER FORCING ALOFT TO THE EAST OVER OHIO. WILL
MAINTAIN LOW CHANCE POPS THROUGH THE AFTERNOON OVER ALL BUT THE
NORTHERN WABASH VALLEY...AND INTO THE EVENING OVER FAR SOUTHERN
COUNTIES.
BUMPED UP HIGHS IN NORTHERN COUNTIES BY A DEGREE OR TWO...
ESPECIALLY WITH A MAINLY SUNNY START BEFORE CU FIELD DEVELOPS
LATER TODAY. OTHERWISE FORECAST HIGH TEMPS LOOK REASONABLE.
ZONE AND GRID UPDATES OUT.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
ISSUED AT 339 AM EDT SAT AUG 10 2013
HIGH PRESSURE WILL BUILD INTO CENTRAL INDIANA TONIGHT...INFLUENCING
THE AREA THROUGH SUNDAY NIGHT. THE NEXT CHANCE FOR ANY MEASURABLE
PRECIP WILL BE MONDAY/MONDAY NIGHT AS A COLD FRONT ENTERS FROM THE
NORTHWEST. THIS FRONT WILL COMBINE WITH SOME MOISTURE RETROGRADING
BACK INTO THE REGION. AS A RESULT...CHANCE POPS SEEM REASONABLE AT
THIS TIME DURING THE MONDAY/MONDAY NIGHT TIME FRAME.
TEMPS...MODELS ARE SHOWING SOME INCONSISTENCY WITH REGARD TO
CHANGING WEATHER PATTERN AT END OF SHORT TERM PERIOD. WENT WITH A
BLEND FROM TONIGHT THROUGH SUNDAY NIGHT...AND THEN LEANED TOWARD
THE WARMER GFS ON MONDAY TO CAPTURE ANY WARM AIR ADVECTION WITH A
SURFACE WARM FRONT.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
ISSUED AT 210 PM EDT SAT AUG 10 2013
MODELS CONTINUE TO BE CLOSE ENOUGH THAT THE ALLBLEND INITIALIZATION
CAN BE USED WITH LITTLE CHANGE.
CENTRAL INDIANA WILL REMAIN UNDER AN UPPER TROUGH THROUGH THE
PERIOD. COOL CANADIAN HIGH PRESSURE AT THE SURFACE WILL PROVIDE DRY
CONDITIONS WITH BELOW AVERAGE TEMPERATURES THROUGH THE PERIOD.
&&
.AVIATION /DISCUSSION FOR THE 101800Z TAFS/...
ISSUED AT 1253 PM EDT SAT AUG 10 2013
GENERALLY VFR CONDITIONS THROUGH THIS EVENING...THEN IFR FOG
DEVELOPING AT MOST SITES OVERNIGHT. VFR RETURNS SUNDAY MID-MORNING.
CU WILL CONTINUE TO DEVELOP...AND CEILINGS FROM THE CU MAY OCCUR AT
TIMES AT THE SITES.
CU WILL DISSIPATE AFTER SUNSET LEAVING CLEAR SKIES. WITH LIGHT WINDS
AND LINGERING LOW LEVEL MOISTURE...EXPECT FOG TO DEVELOP. WILL
CONTINUE WITH IFR FORECAST FOR ALL BUT KIND. FOG WILL BURN OFF
SUNDAY MORNING.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...RYAN
SHORT TERM...TDUD
LONG TERM....50
AVIATION...50
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1253 PM EDT SAT AUG 10 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 339 AM EDT SAT AUG 10 2013
A SECONDARY COLD FRONT WILL TRAVERSE CENTRAL INDIANA
TODAY...BRINGING A SLIGHT CHANCE FOR SOME SCATTERED SHOWERS
THIS MORNING AND ISOLATED THUNDERSTORMS THIS AFTERNOON. HIGH
PRESSURE WILL RESULT IN DRY CONDITIONS FROM TONIGHT THROUGH
SUNDAY. HOWEVER...A WEAK SURFACE LOW WILL TRY TO ENTER CENTRAL
INDIANA FROM THE SOUTH ON MONDAY...FOLLOWED BY A STRONGER COLD
FRONT THAT NIGHT WHICH WILL BRING ADDITIONAL SHOWER AND
THUNDERSTORM CHANCES INTO TUESDAY MORNING.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 955 AM EDT SAT AUG 10 2013
MID AND HIGH LEVEL CLOUDS PERSISTING SO FAR THIS MORNING ACROSS
ALL BUT NORTHERN PORTIONS OF THE FORECAST AREA. A FEW LIGHT
SHOWERS CONTINUE TO GRAZE FAR SOUTHERN COUNTIES AS A WEAK WAVE
ALOFT PASSES THROUGH THE LOWER OHIO VALLEY. TEMPS WERE GENERALLY
IN THE LOWER AND MIDDLE 70S AS OF 13Z.
FORECAST IN GOOD SHAPE THIS MORNING WITH JUST MINOR CHANGES
NEEDED. WEAK SURFACE WAVE ALONG SECONDARY FRONT NOTED ACROSS
NORTHEAST INDIANA WITH THE BOUNDARY EXTENDING SOUTHWEST INTO
CENTRAL ILLINOIS. THE BOUNDARY WILL PROGRESS SLOWLY SOUTH ACROSS
THE FORECAST AREA THROUGH THE AFTERNOON AND EVENING. WHILE FORCING
ALOFT REMAINS VERY WEAK...PRESENCE OF LOW LEVEL MOISTURE AND WEAK
INSTABILITY AHEAD OF THE BOUNDARY WILL LIKELY BE ENOUGH TO
GENERATE ISOLATED CONVECTION THROUGH THE AFTERNOON AND EARLY
EVENING...ESPECIALLY OVER THE SOUTHEAST HALF OF THE FORECAST AREA.
CURRENT HRRR CAPTURES THIS IDEA WELL...HINTING AT BEST POTENTIAL
FOR CONVECTIVE DEVELOPMENT OVER EASTERN COUNTIES WHICH MAKES SENSE
WITH SLIGHTLY BETTER FORCING ALOFT TO THE EAST OVER OHIO. WILL
MAINTAIN LOW CHANCE POPS THROUGH THE AFTERNOON OVER ALL BUT THE
NORTHERN WABASH VALLEY...AND INTO THE EVENING OVER FAR SOUTHERN
COUNTIES.
BUMPED UP HIGHS IN NORTHERN COUNTIES BY A DEGREE OR TWO...
ESPECIALLY WITH A MAINLY SUNNY START BEFORE CU FIELD DEVELOPS
LATER TODAY. OTHERWISE FORECAST HIGH TEMPS LOOK REASONABLE.
ZONE AND GRID UPDATES OUT.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
ISSUED AT 339 AM EDT SAT AUG 10 2013
HIGH PRESSURE WILL BUILD INTO CENTRAL INDIANA TONIGHT...INFLUENCING
THE AREA THROUGH SUNDAY NIGHT. THE NEXT CHANCE FOR ANY MEASURABLE
PRECIP WILL BE MONDAY/MONDAY NIGHT AS A COLD FRONT ENTERS FROM THE
NORTHWEST. THIS FRONT WILL COMBINE WITH SOME MOISTURE RETROGRADING
BACK INTO THE REGION. AS A RESULT...CHANCE POPS SEEM REASONABLE AT
THIS TIME DURING THE MONDAY/MONDAY NIGHT TIME FRAME.
TEMPS...MODELS ARE SHOWING SOME INCONSISTENCY WITH REGARD TO
CHANGING WEATHER PATTERN AT END OF SHORT TERM PERIOD. WENT WITH A
BLEND FROM TONIGHT THROUGH SUNDAY NIGHT...AND THEN LEANED TOWARD
THE WARMER GFS ON MONDAY TO CAPTURE ANY WARM AIR ADVECTION WITH A
SURFACE WARM FRONT.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
ISSUED AT 339 AM EDT SAT AUG 10 2013
ENSEMBLES INDICATE A RATHER STABLE WEATHER PATTERN DURING THIS
PERIOD. SUBTROPICAL RIDGE REMAINS ALONG THE GULF COAST/SOUTHERN
PLAINS REGION...WHILE UPPER TROUGHING CONTINUES OVER THE GREAT LAKES
AND NEW ENGLAND.
ENSEMBLES SUGGEST AN UPPER DISTURBANCE WILL BE IN THE PROCESS OF
PASSING OVER THE GREAT LAKES ON TUESDAY. WILL KEEP SOME CHANCE POPS
IN THE FORECAST ON TUESDAY TO COVER THIS FEATURE.
OTHERWISE...ENSEMBLES INDICATING LITTLE THREAT FOR PRECIPITATION FOR
THE REST OF THE EXTENDED...SO WILL GO DRY AFTER TUESDAY.
&&
.AVIATION /DISCUSSION FOR THE 101800Z TAFS/...
ISSUED AT 1253 PM EDT SAT AUG 10 2013
GENERALLY VFR CONDITIONS THROUGH THIS EVENING...THEN IFR FOG
DEVELOPING AT MOST SITES OVERNIGHT. VFR RETURNS SUNDAY MID-MORNING.
CU WILL CONTINUE TO DEVELOP...AND CEILINGS FROM THE CU MAY OCCUR AT
TIMES AT THE SITES.
CU WILL DISSIPATE AFTER SUNSET LEAVING CLEAR SKIES. WITH LIGHT WINDS
AND LINGERING LOW LEVEL MOISTURE...EXPECT FOG TO DEVELOP. WILL
CONTINUE WITH IFR FORECAST FOR ALL BUT KIND. FOG WILL BURN OFF
SUNDAY MORNING.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...RYAN
SHORT TERM...TDUD
LONG TERM....JAS
AVIATION...50
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
315 PM CDT Sat Aug 10 2013
...updated long term...
.SYNOPSIS...
ISSUED AT 1220 PM CDT SAT AUG 10 2013
At 12z Saturday a 500mb -17c upper low was located just off the
northern California coast. Just east of this upper low the 500mb
low an upper level ridge axis extended from northern Idaho into
west Texas and 500mb thermal trough was located near the four
corners region. An 250mb jet extended from Baja California to New
Mexico. Across eastern Canada an upper low was located near Hudson
bay with one short wave trough located west of this upper low over
Manitoba. An area of higher 700mb dewpoints were located just
northeast of a +4 to +8c temperature gradient extended from
eastern Montana into northeast Kansas. A surface to 850mb high
this morning extended from Iowa into northeast New Mexico.
&&
.SHORT TERM...(This evening through Sunday)
ISSUED AT 217 PM CDT SAT AUG 10 2013
Southeast winds will continue overnight at 10 to 15 mph as a
trough of low pressure at the surface along the lee of the Rockies
deepens. This southeasterly flow will draw low to mid 60 dewpoints
back into southwest Kansas overnight which will give rise to some
patchy fog by morning. Bufr soundings however indicating the low
level moisture will be shallow and low level winds above the
surface will be at 15 to 20kts. In addition high clouds are
expected to spread into the area from the west after midnight. As
a result do not think widespread dense fog will be an issue late
tonight/early Sunday. Lows tonight in the low to mid 60s still
look on track based on the return of low level moisture and
increasing high clouds.
850mb temperatures warm 3-6c between 00z Sunday and 00z Monday,
especially in southwest Kansas. Both the NAM and GFS model
soundings suggest highs on Sunday will climb into the upper 80s to
lower 90s. The upper level disturbance that was located near the
four corners region at 12z Saturday is forecast to rotate around
the upper level ridge axis Saturday night and move across
northeast Colorado/northwest Kansas Sunday afternoon. Mid level
instability will be present across western Kansas by late day and
based on the track of this upper level system a few late day
thunderstorms will be possible after 21z across west central and
north central Kansas.
.LONG TERM...(Sunday night through Saturday)
ISSUED AT 309 PM CDT SAT AUG 10 2013
Thunderstorms are likely to build upscale Sunday night across north
central and central Kansas along the instability axis. The
thunderstorm activity would be driven/aided by a transient middle
level wave. farther southwest toward Elkhart and Liberal, any
convection would Likely be more isolated in nature rather than
widespread. precipitation chances will then be tapered off Monday
morning across the area, and ramped up again Monday evening in
association with the warm front straddled across central Kansas in
vicinity of the central High Plains surface low. best
precipitation/thunderstorm chances will again favor he evening hours
as storms this time may be driven though surface convergence
processes through the evening or overnight (timing of such a feature
is of low forecaster confidence). Temperature trends during this
timeframe range from warm across the region Monday to considerable
cooler behind the increasingly back door high pressure airmass by
Wednesday. By Wednesday, models are depicting considerable clouds if
not scattered upslope induced showers and thunderstorm during the day
as instability increases. The ALLBLEND forecast method carries 40
PoPs for this period.
As northwest flow is maintained aloft, thunderstorms driven/steered
from western initiation points cannot be ruled out anytime during the
period through the weekend. The better odds will be focused along
the high plains region from western Colorado, as diurnal driven
storms initiate along the Palmer divide and sangre de cristo
mountains, and into the Texas panhandle.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
ISSUED AT 1220 PM CDT SAT AUG 10 2013
A trough of low pressure at the surface will develop along the
lee of the Rockies as a surface high slides east across central
Kansas. Southeast winds at around 10kts are expected this
afternoon and overnight. Status was observed across portions of
southwest Kansas earlier this morning and has been slow to erode.
Based on the latest RAP the low clouds will dissipate after 21z as
high level moisture begins to spread into the area from the west.
Moist upslope flow overnight may give rise to some areas of fog
and possibly status after midnight, however based on 12z soundings
IFR/LIFR vsbys from the fog is not anticipated.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 64 89 68 91 / 10 10 30 20
GCK 63 90 67 89 / 10 10 20 10
EHA 63 91 67 91 / 10 10 20 20
LBL 64 91 68 93 / 10 10 20 20
HYS 63 88 67 88 / 10 10 60 20
P28 67 89 71 93 / 10 10 60 30
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BURGERT
SHORT TERM...BURGERT
LONG TERM...RUSSELL
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
218 PM CDT Sat Aug 10 2013
...UPDATED SHORT TERM DISCUSSION...
.SYNOPSIS...
ISSUED AT 1220 PM CDT SAT AUG 10 2013
At 12z Saturday a 500mb -17c upper low was located just off the
northern California coast. Just east of this upper low the 500mb
low an upper level ridge axis extended from northern Idaho into
west Texas and 500mb thermal trough was located near the four
corners region. An 250mb jet extended from Baja California to New
Mexico. Across eastern Canada an upper low was located near Hudson
bay with one short wave trough located west of this upper low over
Manitoba. An area of higher 700mb dewpoints were located just
northeast of a +4 to +8c temperature gradient extended from
eastern Montana into northeast Kansas. A surface to 850mb high
this morning extended from Iowa into northeast New Mexico.
&&
.SHORT TERM...(This evening through Sunday)
ISSUED AT 217 PM CDT SAT AUG 10 2013
Southeast winds will continue overnight at 10 to 15 mph as a
trough of low pressure at the surface along the lee of the Rockies
deepens. This southeasterly flow will draw low to mid 60 dewpoints
back into southwest Kansas overnight which will give rise to some
patchy fog by morning. Bufr soundings however indicating the low
level moisture will be shallow and low level winds above the
surface will be at 15 to 20kts. In addition high clouds are
expected to spread into the area from the west after midnight. As
a result do not think widespread dense fog will be an issue late
tonight/early Sunday. Lows tonight in the low to mid 60s still
look on track based on the return of low level moisture and
increasing high clouds.
850mb temperatures warm 3-6c between 00z Sunday and 00z Monday,
especially in southwest Kansas. Both the NAM and GFS model
soundings suggest highs on Sunday will climb into the upper 80s to
lower 90s. The upper level disturbance that was located near the
four corners region at 12z Saturday is forecast to rotate around
the upper level ridge axis Saturday night and move across
northeast Colorado/northwest Kansas Sunday afternoon. Mid level
instability will be present across western Kansas by late day and
based on the track of this upper level system a few late day
thunderstorms will be possible after 21z across west central and
north central Kansas.
.LONG TERM...(Sunday through Friday)
ISSUED AT 321 AM CDT SAT AUG 10 2013
Sunday:
Medium range models are in fair agreement with a frontal boundary located
across Nebraska Sunday afternoon with an associated lee trof across
eastern Colorado. These boundaries could be the impetus for convection
by late afternoon and evening. As such, have the highest precipitation
probabilities across the western and northern zones by afternoon and
then spreading values southeast in case a MCS comes into fruition. Southwest
Kansas will be in the warm sector with 850 hPa temperatures forecast
in the lower 20sC. This should support mix down temperatures around
the 90F mark. Overnight minimums will be more mild compared to the previous
morning as a result of low level dewpoint advection and southerly winds
with minimum values in the 60s/70sF.
Monday:
The aforementioned front will sink southward during Monday. Again, this
front could be the impetus for convection during the afternoon and evening.
Tried to put some temporal details in the precipitation chances as convection
will be diurnally driven and not much activity is expected during the
morning hours. We could see slightly cooler maximums with more upper
80sF, but confidence is low due to wherever the warm sector ends up.
Minimums will be similar to the night before - 60s/70sF.
Tuesday and beyond:
An upslope flow pattern is expected Tuesday. This favors cooler temperatures
and a continued threat for MCS formation. This activity should be more
orographically induced - drifting across the Kansas prairies during
the evening. Maximums Tuesday will be pleasant and in the lower 80sF.
Beyond Tuesday, there cold be more isolated storms through midweek.
Will continue with the weighted blend solution in the extended as far
as precipitation chances and temperatures are concerned.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
ISSUED AT 1220 PM CDT SAT AUG 10 2013
A trough of low pressure at the surface will develop along the
lee of the Rockies as a surface high slides east across central
Kansas. Southeast winds at around 10kts are expected this
afternoon and overnight. Status was observed across portions of
southwest Kansas earlier this morning and has been slow to erode.
Based on the latest RAP the low clouds will dissipate after 21z as
high level moisture begins to spread into the area from the west.
Moist upslope flow overnight may give rise to some areas of fog
and possibly status after midnight, however based on 12z soundings
IFR/LIFR vsbys from the fog is not anticipated.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 64 88 68 88 / 10 30 30 40
GCK 63 89 67 90 / 10 30 40 40
EHA 63 91 67 91 / 10 30 40 40
LBL 64 91 68 92 / 10 30 30 40
HYS 63 88 67 85 / 10 30 40 40
P28 67 89 71 90 / 10 20 40 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BURGERT
SHORT TERM...BURGERT
LONG TERM...Sugden
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1225 PM CDT Sat Aug 10 2013
...UPDATED SYNOPSIS AND AVIATION DISCUSSION...
.SYNOPSIS...
ISSUED AT 1220 PM CDT SAT AUG 10 2013
At 12z Saturday a 500mb -17c upper low was located just off the
northern California coast. Just east of this upper low the 500mb
low an upper level ridge axis extended from northern Idaho into
west Texas and 500mb thermal trough was located near the four
corners region. An 250mb jet extended from Baja California to New
Mexico. Across eastern Canada an upper low was located near Hudson
bay with one short wave trough located west of this upper low over
Manitoba. An area of higher 700mb dewpoints were located just
northeast of a +4 to +8c temperature gradient extended from
eastern Montana into northeast Kansas. A surface to 850mb high
this morning extended from Iowa into northeast New Mexico.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 257 AM CDT SAT AUG 10 2013
Western Kansas will be in the cool, but modifying airmass in between
two frontal systems. As a result, high temperatures today will be
below average by about 7 to 9 degrees across much of the southwest
Kansas region. Today will be a much appreciated drying out day
(which is unbelievable to say amidst this long-term drought!) with
fairly light winds by western Kansas standards. The surface ridge
will shift to the southeast by afternoon and winds will become
southeasterly with an increase to the 10-15 mph range by mid to late
afternoon. There will terrain-generated thunderstorm activity across
Colorado this afternoon, and mid-upper level flow from the west will
carry any storms that form off the Palmer Divide east toward the
Kansas line by the evening hours. Should any storm survive that far
east, it is most likely to be across far northwest Kansas. As a
result of the very low probability of a storm surviving to
Morton-Stanton-Hamilton County, will decrease POPs to below 15
percent which will essentially come out as a dry forecast. Tonight,
the low level flow off the surface in the 925-850mb layer will
advect higher moisture air from Oklahoma into southern Kansas,
leading to low stratus development in the 09-12z time frame late
tonight. Will increase the Sky grids to mostly cloudy/cloudy
territory mainly across the eastern counties (along/east of Hwy
183). Low temperatures tonight will be in the lower 60s, which is a
bit lower than previous forecast.
.LONG TERM...(Sunday through Friday)
ISSUED AT 321 AM CDT SAT AUG 10 2013
Sunday:
Medium range models are in fair agreement with a frontal boundary located
across Nebraska Sunday afternoon with an associated lee trof across
eastern Colorado. These boundaries could be the impetus for convection
by late afternoon and evening. As such, have the highest precipitation
probabilities across the western and northern zones by afternoon and
then spreading values southeast in case a MCS comes into fruition. Southwest
Kansas will be in the warm sector with 850 hPa temperatures forecast
in the lower 20sC. This should support mix down temperatures around
the 90F mark. Overnight minimums will be more mild compared to the previous
morning as a result of low level dewpoint advection and southerly winds
with minimum values in the 60s/70sF.
Monday:
The aforementioned front will sink southward during Monday. Again, this
front could be the impetus for convection during the afternoon and evening.
Tried to put some temporal details in the precipitation chances as convection
will be diurnally driven and not much activity is expected during the
morning hours. We could see slightly cooler maximums with more upper
80sF, but confidence is low due to wherever the warm sector ends up.
Minimums will be similar to the night before - 60s/70sF.
Tuesday and beyond:
An upslope flow pattern is expected Tuesday. This favors cooler temperatures
and a continued threat for MCS formation. This activity should be more
orographically induced - drifting across the Kansas prairies during
the evening. Maximums Tuesday will be pleasant and in the lower 80sF.
Beyond Tuesday, there cold be more isolated storms through midweek.
Will continue with the weighted blend solution in the extended as far
as precipitation chances and temperatures are concerned.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
ISSUED AT 1220 PM CDT SAT AUG 10 2013
A trough of low pressure at the surface will develop along the
lee of the Rockies as a surface high slides east across central
Kansas. Southeast winds at around 10kts are expected this
afternoon and overnight. Status was observed across portions of
southwest Kansas earlier this morning and has been slow to erode.
Based on the latest RAP the low clouds will dissipate after 21z as
high level moisture begins to spread into the area from the west.
Moist upslope flow overnight may give rise to some areas of fog
and possibly status after midnight, however based on 12z soundings
IFR/LIFR vsbys from the fog is not anticipated.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 84 62 88 68 / 10 10 30 30
GCK 84 62 89 67 / 10 10 30 40
EHA 86 64 91 67 / 10 10 30 40
LBL 86 62 91 68 / 10 10 30 30
HYS 83 63 88 67 / 10 10 30 40
P28 85 65 89 71 / 10 10 20 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BURGERT
SHORT TERM...UMSCHEID
LONG TERM...Sugden
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
134 PM EDT SAT AUG 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM EDT SAT AUG 10 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL LOW OVER NRN
QUEBEC RESULTING IN WNW FLOW THROUGH THE NRN GREAT LAKES. THE MOST
PROMINENT UPSTREAM SHORTWAVE TROUGH WAS LOCATED OVER SW SASK. AT THE
SFC...A WEAK TROUGH EXTENDED FROM JAMES BAY INTO NE LAKE SUPERIOR
WHILE A RIDGE EXTENDED FROM ND INTO MN AND IA. IR LOOP SHOWED MAINLY
CLEAR SKIES OVER UPPER MICHIGAN WHICH HAS ALLOWED TEMPS TO DROP INTO
THE LOWER TO MID 40S INLAND. THE NRN EDGE OF A MORE EXTENSIVE AREA OF
CLOUD HAS REMAINED TO THE WEST AND SOUTH FROM NEAR ASX TO MNM.
TODAY...WITH THE WEAK 850-700 MB THERMAL TROUGH REMAINING NEAR THE
AREA...EXPECT SCT/BKN CU TO AGAIN DEVELOP THIS AFTERNOON. EVEN WITH
PROMINENT LAKE BREEZE BOUNDARIES THIS AFTERNOON IN THE RELATIVELY
LIGHT WIND FIELD...A STRONG CAP/INVERSION AROUND 700 MB...PER MDLS
SOUNDINGS AND AREA 00Z RAOBS...AND DRY LOW LEVELS WILL INHIBIT ANY
PCPN. NO MORE THAN A BRIEF SPRINKLE WOULD BE EXPECTED OUT OF THE
RELATIVELY SHALLOW CONVECTIVE CLOUDS. TEMPS WILL CLIMB TO NEAR
NORMAL...IN THE LOWER TO MID 70S.
TONIGHT...THE SASK SHRTWV WILL APPROACH UPPER MI TONIGHT BUT ANY
PCPN WITH THIS FEATURE IS EXPECTED TO REMAIN TO THE W OF THE CWA.
THE SIGNFICANT PCPN WILL REMAIN WELL TO THE SOUTH...CLOSER TO THE
850 MB FRONT OVER SRN MN. INCREASING MID CLOUDS LATE WILL KEEP TEMPS
FROM FALLING OFF AS MUCH WITH MIN READINGS IN THE MID 40S TO LOWER
50S.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 358 AM EDT SAT AUG 10 2013
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED SUNDAY
AFTERNOON AND MONDAY BEFORE BROAD HIGH PRESSURE GAINS CONTROL OF THE
REGION AND BRINGS AN EXTENDED PERIOD OF DRY WEATHER THROUGH THE
UPCOMING WEEK. TEMPERATURES WILL CONTINUE TO BE SLIGHTLY BELOW
NORMAL...WITH A COUPLE CHILLY NIGHTS EXPECTED FOR THE FIRST PART OF
THE WEEK.
SUNDAY...A BROAD MID-LEVEL TROUGH CENTERED OVER FAR NORTHERN
ONTARIO WILL BE MAKING A SOUTHWARD PUSH AT THE START OF THE PERIOD.
MAIN FORECAST FOCUS CONTINUES TO BE ON THE POTENTIAL FOR AFTERNOON
SHOWERS AND THUNDER ACROSS INTERIOR PORTIONS OF THE CWA. MODEL
GUIDANCE HAS BEEN QUITE PERSISTENT FOR SEVERAL NIGHTS NOW WITH
ADVERTISING THE PASSAGE OF A LEAD SHORTWAVE ACROSS UPPER MI ON
SUNDAY AFTERNOON AND EVENING. THIS WAVE IS A RESULT OF PHASING
BETWEEN SMALL PIECES OF ENERGY FROM WESTERN CANADA AND THE LARGER
TROUGH. THE ECMWF AND GEM ARE THE QUICKEST...AND HAVE THE TROUGH
OUTRUNNING PEAK HEATING BY CLEARING THE EASTERN CWA BY MID
AFTERNOON. THE NAM/LOCAL WRF/GFS ARE SLOWER...AND BRING THE WAVE
ACROSS THE CENTRAL CWA AROUND EARLY AFTERNOON. SUBTLE NW FLOW
FEATURES CAN BE QUITE FICKLE THIS TIME OF YEAR...SO AM NOT TOO
CONFIDENT IN JUMPING ON EITHER SOLUTION ATTM. GIVEN COMPETING
DYNAMICS BETWEEN THE MID-LEVEL WAVE AND THE LEFT ENTRANCE OF AN 80
KT UPPER JET...WILL MAINTAIN THE FOCUS FOR PRECIP CHANCES ACROSS THE
SOUTH CENTRAL AND INTERIOR EAST WHERE ASSISTANCE FROM LAKE BREEZE
CONVERGENCE WILL BOOST DIURNAL ACTIVITY.
ONE CONCERN WITH THUNDER POTENTIAL OVER THE PAST COUPLES DAYS HAS
BEEN LOWER INSTABILITY DUE TO CLOUDS FROM CONVECTION TO THE SOUTH.
WITH MLCAPE PEAKING AT ONLY 500 J/KG FAR SOUTH CENTRAL...THUNDER
COVERAGE WILL BE LIMITED. A DRY SUBCLOUD LAYER COULD STILL RESULT IN
SOME GUSTY WINDS TO 35 MPH WITH ANY SHOWERS THOUGH AS DOWNDRAFT CAPE
WILL BE OVER 500 J/KG.
SUNDAY NIGHT AND MONDAY...ANY ACTIVITY SUNDAY AFTERNOON SHOULD
DIMINISH WITH THE PASSAGE OF THE WAVE AND LOSS OF DAYTIME HEATING. A
WEAK SFC TROUGH ASSOCIATED WITH THE MID-LEVEL TROUGH WILL STILL BE
DRIFTING ACROSS THE EASTERN CWA INTO THE OVERNIGHT HOURS...BUT DO
NOT EXPECT ANY LINGERING SHOWERS GIVEN WEAK LIFT AND DRIER AIR. THE
MAIN TROUGH IS THEN PROGGED TO CROSS THE CWA DURING THE DAY ON
MONDAY. MID-LEVEL Q-VECTOR CONVERGENCE WITH A DECENT UPPER-LEVEL
NEGATIVE PV ANOMALY WILL BRING MODEST LIFT ACROSS THE NORTHERN CWA
AND LAKE SUPERIOR MONDAY AFTERNOON. ONCE AGAIN...DAYTIME HEATING
WILL ASSIST WITH PRECIP COVERAGE IN THE AFTERNOON. DO NOT EXPECT ANY
MORE COVERAGE THAN SUNDAY AFTERNOON AS MID-LEVEL CAPPING BEHIND
SUNDAYS TROUGH WILL LIMIT VERTICAL GROWTH OF ANY SHOWERS. WILL
MAINTAIN GOING FORECAST WITH BEST CHANCE POPS AND SLIGHT CHANCE OF
THUNDER SOUTH-CENTRAL AND INTERIOR EAST IN THE AFTERNOON.
TUESDAY THROUGH FRIDAY...HIGH PRESSURE WILL BUILD INTO THE CWA FROM
THE WEST BEGINNING MONDAY NIGHT AND SETTLE OVER THE REGION TUESDAY
NIGHT. PWAT VALUES OF 0.5 INCHES OR LESS AND LIGHT WINDS WILL LEAD
TO GREAT RADIATIONAL COOLING BOTH MONDAY AND TUESDAY NIGHTS.
GUIDANCE THAT HAS VERIFIED THE BEST OVER RECENT COOL NIGHTS PRODUCES
MIN TEMPS WELL INTO THE 40S INLAND...ESPECIALLY TUESDAY NIGHT. COULD
EVEN SEE SOME UPPER 30S TUESDAY NIGHT AT THE TYPICAL COOL
SPOTS...BUT DID NOT GO THAT LOW QUITE YET GIVEN UNCERTAINTY IN THE
EXACT PLACEMENT OF THE SFC HIGH. OVERALL...LOWERED TEMPS BY A COUPLE
DEGREES FOR BOTH NIGHTS. ALSO ADDED SOME PATCHY FOG ACROSS THE
INTERIOR WEST HALF MONDAY NIGHT SINCE THEY WILL HAVE SEEN A FEW
SHOWERS ON MONDAY AFTERNOON AND CROSSOVER TEMPS SHOULD BE SURPASSED
BY SEVERAL DEGREES.
ANOTHER WEAK TROUGH AXIS FROM THE MAIN EASTERN CANADIAN TROUGH WILL
SKIRT NE LAKE SUPERIOR THURSDAY. WITH MOISTURE LACKING AND BEST
DYNAMICS WELL NORTHEAST...KEPT PRECIP OUT OF THE FORECAST. A
PACIFIC-BASED WAVE COULD BEGIN AFFECTING THE WEST BY LATE
FRIDAY...BUT MODEL CONSISTENCY HAS BEEN POOR SO CONFIDENCE IS LOW IN
ANY PRECIP LATE IN THE WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 134 PM EDT SAT AUG 10 2013
VFR CONDITIONS ARE EXPECTED AT ALL THREE TAF SITES THIS FORECAST
PERIOD. THERE IS A CHANCE OF SOME ISOLATED TO SCATTERED RAIN SHOWERS
AT IWD AND SAW TOWARD THE END OF THE TAF PERIOD...BUT CONFIDENCE IS
TOO LOW AT THIS TIME TO INCLUDE IN THE FORECAST.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 500 AM EDT SAT AUG 10 2013
HIGH PRESSURE MOVING INTO THE WRN GREAT LAKES WILL BRING RELATIVELY
LIGHT WINDS BELOW 20 KNOTS THROUGH THE WEEKEND. A WEAK TROUGH WILL
CROSS THE GREAT LAKES MONDAY...BUT AGAIN...WINDS WILL REMAIN LESS
THAN 20 KNOTS. HIGH PRESSURE WILL RESUME CONTROL OF THE WRN GREAT
LAKES TUESDAY THROUGH THE END OF THE WEEK TO KEEP WINDS GENERALLY
LIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KLUBER
AVIATION...TITUS
MARINE...JLB
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1242 PM CDT Sat Aug 10 2013
.UPDATE:
Issued at 1224 PM CDT Sat Aug 10 2013
A band of strato-cu has developed stretching from near Vichy Missouri to
just south of Taylorville Illinois. Some of the clouds look to
have some decent vertical development so would not be surprised to
see some showers pop out. Have updated the forecast to account for
this. Elsewhere and otherwise the forecast looks good for the rest
of the afternoon.
Carney
&&
.SHORT TERM: (Through Late This Afternoon)
Issued at 317 AM CDT Sat Aug 10 2013
Early morning precipitation over eastern OK and southern MO was
being handled fairly well by the RAP. Based on RAP forecasts of H85
moisture convergence, SHRA/TSRA over southern MO/IL should begin to
taper off after 15Z. Heavy downpours are still possible this morning
since PW values remain near 2 inches. With a surface high pressure
center building into the region and a drier air mass spreading
southward today, any afternoon convection should be confined to
areas closer to the active quasistationary front near the MO/AR
border.
Kanofsky
.LONG TERM: (Tonight through Friday)
Issued at 317 AM CDT Sat Aug 10 2013
All of the 00z NWP output is much more aggressive with the southward
surge of the surface ridge into the mid Mississippi Valley tonight
and into Sunday. Not only will this mean lower dewpoints and
slightly cooler temps, but this will also give the stubborn
baroclinic zone that has been anchored over southern Missouri and
northern Arkansas a gentle but significant southward nudge. This
will greatly lessen the threat of convection that has seemingly
been a nightly occurrence for almost a week over southern Missouri.
I have held onto some low pops in our southern counties both tonight
and Sunday just in case the later solutions back off on the
southward push of the ridge, but if 00z guidance verifies with its
trends any rainfall tonight and Sunday should primarily fall south
of our CWA.
Surface ridge still expected to retreat Sunday night into Monday,
allowing the resultant return flow to cause a northward return of
the warm and moist air. Have continued slight chance pops for most
areas on Sunday night, but it would appear better threat for
convection will hold off until Monday when shortwave energy will be
able to interact with a diurnal increase of instability. This
threat should continue into Monday night. These thunderstorm
chances should shut down with the arrival of the next front...which
the 00z guidance suggests will be about 12 hours slower that earlier
solutions. POPS should diminish from north to south Monday night and
Tuesday.
Consensus of tonight`s medium range guidance dovetails with that of
yesterday`s day shift, and indicates a fairly significant deepening
of the upper trof that is progged to form over the Great Lakes and
eastern U.S during the latter half of next week. This in turn means
stronger high pressure and a bit more of the associated Canadian
airmass backdooring into region. Going trends for the
Wednesday-Friday frame still look very good, with this early surge
of Canadian air providing the region with unseasonably low
humidities and cooler than average temperatures for mid August, and
little if any threat of rain.
Truett
&&
.AVIATION: (For the 18z TAFs through 18z Sunday Afternoon)
Issued at 1224 PM CDT Sat Aug 10 2013
Expect VFR flight conditions and light northerly flow for the rest
of the day. There is a band of strato-cu stretching from near KVIH
to KMTO across the area. Wouldn`t be surprised to see some showers
pop out of these clouds a little later in the day. Also...some
scattered thunderstorms remain possible over parts of the eastern
Ozarks through early evening. Tonight...river valley fog is
possible...tho the chance may be diminished by drier air moving in
from the north.
Specifics for KSTL:
Expect VFR flight conditions and light northerly flow through
Sunday. There is a band of strato-cu stretching from near KVIH
to KMTO across the area. Wouldn`t be surprised to see some showers
pop out of these clouds a little later in the day...but it looks
like any rain should stay south of the terminal.
Carney
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS GLASGOW MT
231 PM MDT SAT AUG 10 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH MONDAY...
MAIN FORECAST CHALLENGE THIS AFTERNOON AND EVENING SURROUNDS THE
CONVECTIVE POTENTIAL ACROSS NORTHEAST MONTANA WITH VIGOROUS
SHORTWAVE DROPPING DOWN FROM SASKATCHEWAN. PERSISTENT GENERAL
SHOWERS AND THUNDERSTORMS HAVE BEEN ONGOING THROUGHOUT THE
NORTHEASTERN ZONES SINCE LATE THIS MORNING. A FEW OF THESE STORMS
HAVE PRODUCED SMALL HAIL AND BRIEF HEAVY DOWNPOURS. BEST
INSTABILITY WITH HIGHEST CAPE VALUES APPEAR TO BE IN THE
SOUTHEASTERN PORTIONS OF THE CWA. HOWEVER...MODEL FORECAST
SOUNDINGS SHOW A CAP IN PLACE. IN ADDITION...HIGH CLOUDINESS HAS
FILTERED OUT SOME SUNSHINE EARLY THIS AFTERNOON REDUCING
INSOLATION. THIS PLACES A BIG QUESTION MARK IN THIS PART OF THE
FORECAST. ANY STORMS THAT DEVELOPED IN THIS AREA WERE EXPECTED TO
BECOME STRONG. IT IS STILL UNCLEAR HOW THE LATE AFTERNOON AND
EVENING WILL UNFOLD. MODEL GUIDANCE CONTINUES TO SHOW SUPPORT FOR
CONVECTION BUT RECENT HRRR SOLUTIONS HAVE BACKED DOWN JUST A BIT.
WILL KEEP THE FORECAST GOING FOR NOW AS IS BUT WILL NEED TO
MONITOR FOR CHANGES. GIVEN INSTABILITY...ANY STORMS THAT DEVELOP
AND/OR PUSH INTO THE SOUTHEAST LATER THIS AFTERNOON OR EVENING MAY
BE CAPABLE OF SMALL HAIL AND GUSTY WINDS. CUMUMULUS FIELD
BEGINNING TO SHOW UP IN VISIBLE SATELLITE IMAGERY ACROSS RICHLAND
COUNTY. THERE WAS MUCH MORE IN THE WAY OF SUNSHINE IN
RICHLAND...NORTHERN DAWSON...AND NORTHERN WIBAUX COUNTY AND THIS
IS THE AREA THAT WILL NEED TO BE WATCHED MOST CLOSELY FOR STRONGER
STORMS. NOT GOING TO INTRODUCE SEVERE WORDING INTO THE GRIDS AS
THERE IS JUST TOO MUCH UNCERTAINTY. IN ADDITION...SPC SSEO
SUGGESTS SEVERE POTENTIAL WOULD BE FURTHER SOUTH AND EAST OF THE
FORECAST REGION. WILL NOT RULE OUT AN ISOLATED SEVERE THUNDERSTORM
TODAY BUT POTENTIAL FOR THAT SHOULD BE BETTER TO THE SOUTH AND
EAST OF THE CWA. ASIDE FROM THE ROBUST SHORTWAVE PUSHING THROUGH FROM
SASKATCHEWAN...ADDITIONAL SHOWERS/THUNDERSTORMS ARE POSSIBLE
ACROSS PHILLIPS COUNTY WITH A VERY WEAK SHORTWAVE EMBEDDED IN THE
UPPER FLOW PATTERN PUSHING THROUGH THIS EVENING. WILL KEEP
ISOLATED SHOWERS/STORMS IN THOSE LOCATIONS THIS EVENING.
SUNDAY INTO MONDAY...10/12Z MODEL GUIDANCE CONTINUES TO BRING UPPER
RIDGE CLOSER INTO THE CWA. THIS SHOULD PROMOTE LARGE SCALE
SUBSIDENCE. WILL NOT RULE OUT DIURNALLY DRIVEN CONVECTION BUT WITH
LITTLE MOISTURE AND NOT LIFTING MECHANISM...NOTHING MORE THAN
ISOLATED IS ANTICIPATED. TEMPERATURES SHOULD ALSO GRADUALLY
INCREASE WITH RISING HEIGHTS AND WARMING 850MB TEMPERATURES WITH
THE RIDGE BUILDING IN. MALIAWCO
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...
UPPER RIDGE GRADUALLY BUILDS INTO MONTANA DURING THE EXTENDED
PERIOD.
FOR TUESDAY AND WEDNESDAY...THERE WILL BE A SLOW MOVING WARM FRONT
WHICH WILL BE THE FOCUS FOR SHOWERS AND THUNDERSTORMS AT TIMES.
THE STORMS WILL BE PARTLY DRIVEN BY DAYTIME INSTABILITY AND PARTLY
DRIVEN BY SHORTWAVES THAT OVERTOP THE RIDGE AXIS. MODELS TIME THE
WAVES DIFFERENTLY WHICH RESULTS IN MODELS TIMING THE STORMS
DIFFERENTLY. AT THIS POINT... IT LOOKS LIKE THE BEST CHANCE FOR
STORMS WILL BE WEDNESDAY AFTERNOON AND EVENING WHEN THE WARM FRONT
IS OVER EASTERN MONTANA. IT MAY BE UNSTABLE ENOUGH FOR SEVERE
STORMS ON WEDNESDAY. THE CHANCES OF SHOWERS AND THUNDERSTORMS
COULD LINGER INTO THURSDAY DEPENDING ON HOW FAST THE FRONT MOVES
EAST.
BY FRIDAY...THE UPPER RIDGE TAKES CONTROL OF THE WEATHER.
TEMPERATURES WILL WARM TO NEAR 90 POSSIBLY WARMER BOTH FRIDAY AND
SATURDAY WITH LITTLE OR NO CHANCE OF PRECIPITATION. FORRESTER
&&
.AVIATION...
VFR. SCATTERED THUNDERSTORMS WILL BE AFFECTING SOME OF THE AIRPORTS
THIS AFTERNOON. EXPECT GUSTY/ERRATIC WINDS...BRIEF HEAVY RAIN AND
POSSIBLY HAIL. CLEARING AND LIGHT WINDS MAY LEAD TO PATCHY FOG
LATE TONIGHT. TFJ
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
1003 AM MDT SAT AUG 10 2013
.UPDATE...
NO MAJOR ADJUSTMENTS TO THE FORECAST THIS MORNING. TWEAKED POPS
TO LINE UP BETTER WITH SURROUNDING OFFICES...ADJUSTED WINDS AND
CLOUD COVER FOR CURRENT TRENDS. RIDGE OF HIGH PRESSURE WILL BUILD
TO THE WEST OF THE AREA TODAY...CLIPPING WESTERN ZONES WITH DRIER
AND WARMER AIR. AS THE RIDGE BUILDS TO THE WEST WILL SEE SOME
HEIGHT FALLS TO THE EAST ALLOWING A WEAK DISTURBANCE OVER
NORTHWEST MONTANA TO SLIDE SOUTHEAST AND STRENGTHEN JUST A BIT.
THE APPROACH OF THIS WAVE ALONG WITH WARMER TEMPERATURES TO THE
WEST WILL DEEPEN SURFACE LOW PRESSURE OVER WESTERN ZONES ALLOWING
SLIGHTLY COOLER AIR AND NORTHEAST WINDS TO PUSH WESTWARD THIS
AFTERNOON AND EVENING. THE COMBINATION OF THIS WEAK SURFACE
BOUNDARY AND THE WAVE ALOFT HAS THE MODELS DEVELOPING SCATTERED
CONVECTION OVER THE AREA THIS AFTERNOON AND EVENING. STORMS TO THE
WEST WILL BE HIGH BASED AND LOOK PRETTY DRY SO GUSTY WINDS WILL BE
THE MAIN THREAT WEST OF A HARLOWTON TO COLUMBUS LINE WITH ANY
STORMS. TO THE EAST OF THE LINE HIGHER RH VALUES WILL KEEP STORMS
WET AND HEAVY RAINFALL IS A POSSIBILITY WITH ANY STORMS. OVER FAR
EASTERN ZONES SHEAR PROFILES ARE STRONGER AS THIS AREA CATCHES THE
TAIL END OF AN UPPER LEVEL JET. SHEAR LOOKS TO BE IN THE 30 TO 40
KT RANGE WITH A FEW HI RES MODELS SHOWING STRONGER POCKETS.
HODOGRAPHS SHOW STORM SPLITTING PROFILE WITH RIGHT MOVERS MOVING
PERPENDICULAR TO THE LOW LEVEL INFLOW WHICH MEANS THAT A FEW
LONGER LIVED AND THUS STRONGER CELLS ARE POSSIBLE. CERTAINLY NOT A
HIGH END THREAT BUT WOULD EXPECT A FEW WARNING CALIBER STORMS TO
BE MIXED IN WITH SCATTERED STORM COVERAGE THIS AFTERNOON FOR AREAS
EAST OF ROSEBUD COUNTY. TEMPERATURES TODAY WILL BE IN THE MID TO
UPPER 80S WEST WITH LOW 80S TO MAYBE UPPER 70S EAST. LOTS OF
OUTDOOR EVENTS THIS WEEKEND ACROSS THE AREA SO MAKE SURE TO HAVE A
PLAN TO GET TO SHELTER SHOULD STRONG STORMS DEVELOP TODAY.
CHAMBERS
&&
.SHORT TERM...VALID FOR TDY AND SUN...
A WARMING TREND WILL BEGIN TODAY AND CONTINUE INTO SUN WITH HEIGHT
RISES ALOFT...BUT LOW-LEVEL EASTERLY FLOW WILL KEEP SOME CHANCE OF
STORMS IN THE FORECAST...ESPECIALLY IN SOUTHEASTERN MT.
TODAY...WE WILL KEEP A MENTION OF PATCHY FOG IN THE FORECAST UNTIL
15 UTC FOR MOST OF THE AREA WITH SURFACE DEWPOINT DEPRESSIONS LESS
THAN 10 F OVER PARTS OF THE AREA AS OF 09 UTC. HOWEVER...NOT A LOT
OF SUPPORT EXISTS FOR ITS FORMATION IN GUIDANCE...INCLUDING RECENT
RUNS OF THE HRRR...WHICH OFTEN PICKS UP ON THIS SITUATION. WE ALSO
KEPT LOW POPS IN SOUTHEASTERN MT THROUGH 15 UTC TO ACCOUNT FOR THE
SLOW EXIT OF A WEAK SHORT WAVE IN THAT REGION. THE BIG PICTURE FOR
TODAY WILL FEATURE MODEST HEIGHT RISES ALOFT...AND A WARMING TREND
AT THE SURFACE. WE HAVE SLIGHT CHANCE POPS IN THE FORECAST FOR THE
AFTERNOON EVERYWHERE...BUT THAT WAS ACTUALLY A REDUCTION IN VALUES
FOR SOUTHEASTERN MT BECAUSE IT LOOKS LIKE FORCING FOR STORMS COULD
HOLD OFF UNTIL 00 UTC OR LATER IN THAT AREA. THE EASTERLY FLOW AND
MLCAPE TO 500 J/KG IN SOUTH CENTRAL MT MAY YIELD CONVECTION ACROSS
THE HIGHER TERRAIN THIS AFTERNOON TOO...WITH A TENDENCY FOR ANY OF
THAT ACTIVITY TO MOVE EASTWARD INTO THE LOWER ELEVATIONS SINCE THE
BOUNDARY LAYER SHOULD NOT BE TOO CAPPED. WE CHOSE TO LEAVE POPS IN
THE 20 PERCENT RANGE EVEN IN SOUTH CENTRAL MT THOUGH DESPITE QUITE
A BIT OF SUPPORT FOR STORMS IN HIGH-RESOLUTION GUIDANCE BECAUSE IT
IS POSSIBLE THAT THE SYNOPTIC-SCALE ENVIRONMENT /RISING HEIGHTS AT
500 HPA/ WILL INHIBIT MORE THAN ISOLATED DEVELOPMENT.
TONIGHT...CONFIDENCE IS INCREASING IN THUNDERSTORMS OVER SOUTHEAST
MT DURING THE EVENING AS THE CONVECTIVELY-ACTIVE SHORT WAVE TROUGH
OBSERVED OVER NORTHERN ID ON 09 UTC MOISTURE CHANNEL IMAGES SHEARS
SOUTHEAST INTO THE NORTHERN HIGH PLAINS. SEVERAL MEMBERS OF THE 00
UTC SPC SSEO KEY ON SOUTHEASTERN MT FOR CONVECTION IN THE 00 TO 06
UTC TIME FRAME...AND RECENT RAP RUNS ALSO SIMULATE CONVECTION OVER
THAT AREA /ALBEIT A BIT EARLIER/. FORECAST SOUNDINGS CALL FOR 1000
TO 1500 J/KG OF MLCAPE AND 0-6-KM BULK SHEAR NEAR 40 KT...WHICH IS
SUFFICIENT FOR ORGANIZED SEVERE STORMS. WE CHOSE TO INCLUDE A RISK
OF SEVERE STORMS IN THE FORECAST...BUT WE HAVE TO ADMIT IT REMAINS
VERY CONDITIONAL ON STORMS ACTUALLY FORMING. FINALLY..IF STORMS DO
DEVELOP OVER THE HIGHER TERRAIN IN SOUTH CENTRAL MT THIS AFTERNOON
THEN THEY WILL LIKELY CONTINUE SPREADING EAST THIS EVENING...WHICH
WILL BE THE HIGHEST PROBABILITY FOR BILLINGS TO SEE IMPACTS FROM A
STORM. DEEP-LAYER SHEAR IS WEAKER IN SOUTH CENTRAL MT...BUT WITH A
WELL-MIXED BOUNDARY LAYER...STRONG AND GUSTY WINDS ARE POSSIBLE IF
STORMS DO AFFECT THE AREA.
SUN...A MUCH DRIER AND MORE DEEPLY MIXED AIR MASS WILL SPREAD INTO
SOUTH CENTRAL MT...WITH FORECAST SOUNDINGS SUGGESTING MIXING COULD
LOWER DEWPOINTS INTO THE 20S F IN PLACES LIKE LIVINGSTON. EASTERLY
FLOW WILL MAINTAIN DEEPER MOISTURE OVER SOUTHEASTERN MT...WITH LOW
AND CONDITIONAL POPS FOR STORMS THUS WARRANTED IN THAT AREA. HIGHS
WILL TAKE ANOTHER MOVE UPWARD WITH MORE WARMING ALOFT. SCHULTZ
.LONG TERM...VALID FOR MON...TUE...WED...THU...FRI...
ONLY SMALL ADJUSTMENTS WERE MADE TO THE EXTENDED PERIOD FORECASTS
FOR THIS MORNINGS PACKAGE. CONFIDENCE IS HIGH IN AN AMPLIFIED
RIDGE OVER THE REGION WITH PRECIPITABLE WATER HIGHEST IN THE EAST
AND LOWEST IN THE WEST. THEREFORE...THE CHANCE OF MEASURABLE
PRECIPITATION WILL BE HIGHER IN THE EASTERN ZONES. WE CONTINUE TO
SEE PERIODS OF NOCTURNAL STORMS POSSIBLE IN THE CENTRAL AND EAST
DUE TO LOW LEVEL JET ACTIVITY. HIGH PRESSURE ALOFT DOES BREAK
DOWN AT MIDWEEK AS A SHORT WAVE ROUNDS THE RIDGE AND INTERACTS
WITH THE MOISTURE OVER THE EAST FOR A BETTER CHANCE OF
THUNDERSTORMS. THE RIDGE THEN STRENGTHENS LEADING TO ABOVE NORMAL
TEMPERATURES. I BEGAN TRENDING AFTERNOON HIGHS UP FOR THE LATTER
PART OF NEXT WEEK BASED ON THESE TRENDS. BT
&&
.AVIATION...
EXPECT ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS TO IMPACT
THE AREA THIS AFTERNOON AND EVENING...WITH LOCALLY REDUCED
VISIBILITIES AND CEILINGS. VFR CONDITIONS WILL PREVAIL OTHERWISE
TODAY. PATCHY FOG IS POSSIBLE AGAIN LATE TONIGHT FROM KBIL EAST.
JKL
&&
.PRELIMINARY POINT TEMP/POPS...
TDY SUN MON TUE WED THU FRI
-------------------------------------------------------
BIL 084 059/089 060/089 060/087 060/087 059/091 059/092
2/T 31/U 12/T 22/T 22/T 21/U 10/U
LVM 086 051/090 051/088 051/088 052/087 052/089 051/090
2/T 21/U 12/T 22/T 22/T 21/U 11/U
HDN 087 057/092 059/091 060/089 059/089 058/092 059/095
2/T 32/T 12/T 32/T 22/T 21/U 11/U
MLS 083 060/087 063/089 063/088 061/088 060/091 062/094
2/T 42/T 22/T 22/T 23/T 31/U 11/U
4BQ 084 055/088 059/089 061/088 058/087 057/090 059/093
2/T 42/T 22/T 33/T 33/T 31/U 11/U
BHK 078 056/082 058/084 059/083 057/083 057/087 058/089
2/T 42/T 22/T 22/T 23/T 32/T 11/U
SHR 084 054/089 054/088 057/087 055/087 055/088 055/091
2/T 32/T 22/T 23/T 33/T 31/U 11/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS MEDFORD OR
221 PM PDT SAT AUG 10 2013
.DISCUSSION...THE UPPER LOW CONTINUES TO SPIN OVER SOUTHWEST
OREGON WITH SEVERAL SHORTWAVES MOVING THROUGH TODAY. THUNDERSTORMS
ARE ALREADY BLOWING UP ALONG THE CASCADES AND EASTERN DOUGLAS
COUNTY. MEANWHILE THE MID LEVEL CLOUD SHIELD IN WESTERN SISKIYOU
COUNTY IS ERODING...SO IT COULD BE A TIMING ISSUE AS TO HOW MUCH
THUNDERSTORM ACTIVITY DEVELOPS IN NORTHERN CAL...JOSEPHINE AND
JACKSON COUNTIES. FURTHER NORTH THUNDERSTORMS WILL CONTINUE TO
INCREASE IN COVERAGE THROUGH EARLY THIS EVENING WITH SOME THAT COULD
BE MODERATE TO SEVERE PRODUCING MODERATE TO HEAVY RAIN...HAIL AND
GUSTY OUTFLOW WINDS. MODIFIED THE MORNING SOUNDING FOR THAT IT`S
EXPECTED TO LOOK LIKE THIS AFTERNOON AND IT`S SHOWING CAPE VALUES
NEAR 1400 J/KG AND PRECIPITABLE WATER VALUES NEAR AN INCH AND LIFTED
INDICES NEAR -6. THE RAP 13 AND LOCAL HRRR MODELS PUT MOST OF THE
QPF ALONG AND WEST OF THE CASCADES AND HAVE THUS INCREASED POPS AND
QPF IN THESE AREAS. HOWEVER MID LEVEL MOISTURE WILL INCREASE IN
NORTHERN KLAMATH AND LAKE COUNTIES WITH AT THE SAME TIME SHORTWAVES
ARE APPROACHING. SO EXPECT THIS AREA TO SEE INCREASED ACTIVITY AS
WELL.
RIGHT NOW...NOT MUCH IS GOING ON IN MODOC AND SOUTHERN LAKE
COUNTY...BUT WERE GETTING CUMULUS DEVELOPMENT AND EXPECT SOME
ACTIVITY THERE LATE THIS AFTERNOON.
THE UPPER LOW WILL MOVE INTO THE NORTHWEST PART OF THE FORECAST AREA
TONIGHT WITH A SOUTHWEST FLOW ALOFT DEVELOPING. THUNDERSTORMS SHOULD
DECREASE LATER THIS EVENING...THEN THE FOCUS FOR STORMS TONIGHT IS
EXPECTED TO SHIFT OVER THE NORTHERN CASCADES...NORTHERN LAKE AND
KLAMATH COUNTIES.
THE UPPER LOW FINALLY MOVES NORTH OF THE AREA SUNDAY AND WE`LL GET
INTO A SOUTHWEST FLOW ALOFT. THE CASCADES...EASTSIDE AND PARTS OF
THE SISKIYOUS HAVE THE BEST CHANCE OF GETTING THUNDERSTORMS IN THE
AFTERNOON AND EARLY EVENING...BUT IT`S POSSIBLE ISOLATED STORMS
COULD DEVELOP ALONG THE SISKIYOUS.
THE UPPER LOW CONTINUES TO MOVE NORTH AND WEAKEN MONDAY WITH A
CONTINUED SOUTHWEST FLOW OVER THE AREA. THE HIGHEST CHANCE FOR
THUNDERSTORMS WILL BE ALONG THE CASCADES INTO NORTHERN LAKE AND
KLAMATH COUNTIES. EVEN THEN WERE NOT EXPECTING ANYTHING SIGNIFICANT.
THE EC AND GFS SHOW ANOTHER UPPER LOW SETTING SHOP WEST OF THE GULF
OF ALASKA WITH A CONTINUES SOUTHWEST FLOW OVER THE AREA. THIS WILL
RESULT IN DRY CONDITIONS WITH TEMPERATURES NEAR NORMAL. WHILE I
CANNOT RULE OUT ANY CHANCE OF PRECIPITATION EAST OF THE
CASCADES...THE ODDS ARE LOW THAT WE`LL GET ANYTHING. -PETRUCELLI
&&
.AVIATION...BASED ON THE 08/18Z TAF CYCLE.
MAIN CONCERN THROUGH THIS EVENING WILL BE SCATTERED THUNDERSTORMS
FOR INLAND LOCATIONS. SOME OF THESE STORMS COULD BECOME SEVERE
PRODUCING GUSTY OUTFLOW WINDS IN THE VICINITY OF STORMS AND HAIL.
THERE IS ALSO A CHANCE FOR BRIEF MVFR CIGS AND REDUCTION IN VIS IN
HEAVIER STORMS BETWEEN 22-03Z. STORMS MOVEMENT WILL GENERALLY MOVE
FROM EAST TO WEST AFFECTING THE WESTSIDE TERMINALS.
AT THE COAST...EXPECT IFR CIGS TO RETURN BETWEEN 2-3Z AND CONTINUE
INTO SATURDAY MORNING. THERE IS A CHANCE FOR SOME ELEVATED
CONVECTION TO BE IN THE VICINITY OF KOTH BETWEEN 22-2Z.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...RED FLAG WARNING UNTIL 11 PM PDT THIS EVENING FOR
ORZ023>026-028-029.
RED FLAG WARNING UNTIL 11 PM PDT SUNDAY FOR ORZ027-030-031.
CA...RED FLAG WARNING UNTIL 11 PM PDT THIS EVENING FOR CAZ080.
PACIFIC COASTAL WATERS...NONE.
$$
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
242 PM MDT SAT AUG 10 2013
.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 119 PM MDT SAT AUG 10 2013
CURRENT SURFACE ANALYSIS PLACES HIGH OVER THE MIDWEST WITH LOW
OVER THE CENTRAL ROCKIES WHILE FRONTAL BOUNDARY CONTINUES TO
STRETCH ALONG THE NEBRASKA/SOUTH DAKOTA BORDER. UPPER LEVEL
ANALYSIS PLACES LOW SPINNING ALONG THE NRN CALIFORNIA/SRN OREGON
COAST WHILE NEGATIVELY TILTED RIDGE STRETCHES FROM THE SRN PLAINS
UP INTO THE NRN ROCKIES. SERIES OF SHORT WAVES CONTINUE TO LIFT
THROUGH THE RIDGE.
FOR THE REST OF THIS AFTERNOON INTO THIS EVENING...NEXT WAVE
PUSHING THROUGH CENTRAL WYOMING CONTINUES IT SLOW APPROACH TOWARDS
THE AREA WHICH WILL RESULT IN SOME STORMS DEVELOPING. THIS WAVE
APPEARS TO BE MORE SUBTLE THAN LAST NIGHTS...SO EXPECT STORMS TO
BE MORE ISOLD/SCT. THERE IS A SEVERE CONCERN...THOUGH...AS ~30-40
KTS 0-6KM BULK SHEAR WILL IN PLACE COMBINED WITH CAPE VALUES ~1-2
KJ/KG. THEREFORE WILL HAVE TO KEEP AN EYE ON ANY STORMS THAT DO
DEVELOP. ALSO...IF AFOREMENTIONED SFC BOUNDARY CREEPS A BIT MORE
NORTH MAY HAVE TO KEEP AN EYE OF STORMS THAT MOVE ALONG IT FOR A
BRIEF TORNADIC THREAT...THOUGH THIS DOES REMAIN QUITE LOW. MOST
STORMS SHOULD DISSIPATE BY LATE TONIGHT BUT HAVE KEEP SOME LOW
POPS IN LATE AS HIGH RES MODELS HAVE BEEN CONSISTENT WITH THE
POSSIBILITY OF A FEW STORMS LOITERING AROUND. GIVEN THE PERSISTENT
PATTERN OF LATE NIGHT CONVECTION HAVE A HARD TIME RULING THIS OUT.
WITH THE AMPLE LOW LEVEL MOISTURE IN PLACE COMBINED WITH THE LIGHT
EASTERLY FLOW...EXPECT SOME PATCHY FOG MAY DEVELOP LATE ALONG THE
EASTERN FLANKS OF THE BLACK HILLS INTO THE PLAINS A BIT.
ON SUNDAY...AFOREMENTIONED FOG SHOULD DISSIPATE EARLY.
OTHERWISE...QUIET CONDITIONS ARE EXPECTED UNTIL AFTERNOON WHEN THE
NEXT IN OUR LITTLE PARADE OF SHORT WAVES SLIDE THROUGH THE
PERSISTENT PATTERN. AGAIN...SEVERE THREAT REMAINS WITH INCREASING
INSTABILITY THOUGH SHEAR WILL BE MODEST. MAIN CONCERN MAY BE NEAR
SFC BOUNDARY TOWARDS THE NEBRASKA BORDER.
&&
.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 119 PM MDT SAT AUG 10 2013
MEAN WESTERN NOAM RIDING TO REMAIN IN THE PERIOD...WITH
DOWNSTREAM NEGATIVE HEIGHT ANOMALIES LINGERING IN EASTERN NOAM. NE
PAC TROUGHING WILL SUPPORT NUMEROUS SUBTLE IMPULSES IN THE
FLOW...WITH A MORE SUBSTANTIAL WAVE POSSIBLE TOWARD THE END OF NEXT
WEEK...SUPPORTING AN EASTERN BIAS TO THE WESTERN CONUS RIDGE.
MEANWHILE A NORTHERN STREAM UPPER TROUGH WILL GRAZE THE REGION
MONDAY...SUPPORTING A PSEUDO BACKDOOR FRONT INTO THE AREA...STALLING
OVER THE WESTERN HALF OF THE AREA...AND PROVIDING A PATHWAY FOR
PERTURBED WNW FLOW THROUGH MID WEEK. MEAN ENSEMBLES AS WELL AS THE
ECMWF ARE SUPPORTING A REMOVAL OF THE HIGH LATITUDE BLOCKING RIDGE
WITH MORE PROGRESSIVE TENDENCIES TO THE FLOW OVER WESTERN CANADA
TOWARD THE END OF THE WEEK. HOWEVER...ECMWF AND GFS DETERMINISTIC
RUNS SUPPORT ANOTHER ROUND OF STAUNCH WESTERN NOAM RIDGING MUCH MORE
PRONOUNCED THAN THE CURRENT WESTERN NOAM RIDGE...WITH NEGATIVE
HEIGHT TENDENCIES OVER SE CANADA ONCE AGAIN. IF LL MOISTURE REMAINS
AS IN THE ECMWF PROGS...AN ACTIVE PATTERN COULD CERTAINLY RETURN TO
THE REGION...ESP IF DOWNSTREAM BLOCKING DEVELOPS ONCE AGAIN.
RETAINED LOW PRECIP CHANCES THROUGH THUR...CONTINUED WITH A DRY
FRIDAY AND SAT GIVEN FLOW RE-ADJUSTMENT AND UPPER RIDGING/WARMING.
TEMPS WILL REMAIN AROUND SEASONAL NORMS THROUGH MID WEEK WITH A
WARMING TREND INTO NEXT WEEKEND AS THE UPPER RIDGE SHIFTS EAST.
&&
.AVIATION...FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON
ISSUED AT 119 PM MDT SAT AUG 10 2013
WEAK IMPULSE COUPLED WITH DIURNAL HEATING WILL SUPPORT
SCT SHRA/TS ACTIVITY OVER THE BLACK HILLS THIS AFTERNOON...AND THE
REMAINDER OF NE WY AND WESTERN SD LATE THIS AFTERNOON/EVENING. HAVE
OPTED FOR JUST A VCTS MENTION AT THE TERMINALS GIVEN EXPECTED LOW
COVERAGE. SCT MVFR CIGS MAY PERSIST INTO EARLY THIS AFTERNOON OVER
THE EASTERN BH FOOTHILLS...GIVEN UPSLOPE FLOW WITH A MOIST BL. HAVE
ADDED A TEMPO AT KRAP FOR THIS. OTHERWISE...IFR CIGS ARE POSSIBLE
TOWARD THE END OF THE PERIOD...AFT 10Z SUNDAY. THERE IS A PRETTY
STRONG SIGNAL FOR LOW STRATUS DEVELOPMENT OVER MUCH OF WRN/CNTRL SD
AS MOIST UPSLOPE FLOW PERSISTS. THIS IS HINTED AT BOTH IN THE SREF
AND MET GUIDANCE. HAVE TRENDED TO SCT IFR CIGS AT RAP FOR NOW.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
SHORT TERM...77
LONG TERM...JC
AVIATION...JC
AREA FORECAST DISCUSSION
NWS MIDLAND/ODESSA TX
247 PM CDT SAT AUG 10 2013
.DISCUSSION...
A weak cold front that had moved into the region yesterday had a bit
of a push this morning from overnight convection and is now stalled
from the Big Bend eastward into central TX. The NAM and RUC have
convection developing along southern portions of the boundary and
rapidly developing CU marking this boundary can be seen on visible
satellite. A few showers already showing up across the southeastern
zones and went ahead and added isolated mention to this area for the
remainder of today. Otherwise, easterly upslope flow and a
persistent theta e ridge may result in showers and thunderstorms
across the higher terrain and SE New Mexico this evening and could
linger overnight with upper level weaknesses moving through New
Mexico on the western periphery of the upper ridge. Will keep
chance POPs going across these areas during this time.
The NAM has convection developing once again Sunday across much of
the region. It is the most aggressive with QPF output and will only
include slight chance across most of the area. Think highest chances
will remain across SE NM as another disturbance moves east through
the TX Panhandle Sunday afternoon. Rain chances will continue into
the overnight hours mainly across the Permian Basin. PWATs will
remain higher through the weekend so will keep mention of potential
heavy rainfall. Monday, the upper ridge begins to move back west and
rain chances decrease for our area for at least a few days. In
general, temperatures will remain cooler than what we experienced
last week.
By mid week, the upper ridge will be centered over the Desert
Southwest leaving west TX and SE NM under weak NW flow aloft. Hard
to tell if any disturbances moving SE in the flow aloft will affect
us just yet but will keep an eye on it. Models are hanging onto a
weak cold front sagging into the region Wednesday afternoon/evening,
increasing rain chances across the northern PB through Thursday
morning. For now, will hold off on increasing POPs in the grids.
Expect temperatures to cool toward normals for the end of the work
week.
&&
.PRELIMINARY POINT TEMPS/POPS...
ANDREWS TX 71 94 73 95 / 30 10 20 10
BIG SPRING TX 73 96 74 96 / 20 10 20 10
CARLSBAD NM 69 91 72 95 / 30 20 10 10
DRYDEN TX 77 99 76 98 / 20 20 10 10
FORT STOCKTON TX 72 95 72 96 / 20 20 10 10
GUADALUPE PASS TX 65 87 67 89 / 30 20 10 10
HOBBS NM 67 89 71 92 / 30 20 20 10
MARFA TX 62 86 63 86 / 30 20 10 10
MIDLAND INTL AIRPORT TX 72 95 73 96 / 20 10 20 10
ODESSA TX 73 95 74 95 / 20 10 20 10
WINK TX 74 96 75 98 / 30 20 20 10
&&
.MAF WATCHES/WARNINGS/ADVISORIES...
NM...NONE.
TX...NONE.
&&
$$
44/27
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
1219 PM CDT SAT AUG 10 2013
.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
&&
.AVIATION...HRL AIRPORT WILL BE IN A FAVORED AREA FOR NEW
SHOWER/THUNDERSTORM DEVELOPMENT FOR THE NEXT FEW HOURS. AREA OF
CONVECTIVE ACTIVITY WILL MOVE TOWARDS MFE AND PERSIST FOR ANOTHER
2 TO 3 HOURS. BROWNSVILLE IS LESS LIKELY TO SEE NEW THUNDERSTORM
DEVELOPMENT...BUT SUN WILL LIKELY RETURN LATER AND MAY AID IN
DEVELOPING NEW ACTIVITY IN 2 TO 4 HOURS.
MAIN BAND OF DEEPER CONVECTION/15 TO 20 MINUTES OF MVFR TO IFR VIS/
WILL PERSIST BETWEEN THE 77 AND 281 CORRIDOR AND SLOWLY SHIFT
WESTWARD THROUGH MID TO LATE AFTERNOON. OFF AND ON SHOWERS WILL BE
POSSIBLE THROUGHOUT THE ENTIRE AREA THROUGH THE AFTERNOON.
STRONGER WIND GUSTS WILL BE POSSIBLE IN THE WESTERN 3 COUNTIES OF
DEEP SOUTH TEXAS WITH ANY THUNDERSTORMS.
A GENERAL DOWNWARD TREND IS EXPECTED THIS EVENING WITH MORE
ISOLATED SHOWERS OVERNIGHT BEFORE ANOTHER ROUND OF CONVECTION
BEGINS DEVELOPING BY 9 TO 10 AM SUNDAY MORNING. WINDS SHOULD BE
LIGHT TO MODERATE OUT OF THE EAST TO NORTHEAST. OUTSIDE OF
THUNDERSTORMS EXPECTING PREVAILING VFR CONDITIONS THROUGH THE TAF
PERIOD. /68-JGG/
&&
.PREV DISCUSSION... /ISSUED 1206 PM CDT SAT AUG 10 2013/
DISCUSSION...RADAR SHOWS SCATTERED TO NUMEROUS CONVECTIVE CELLS
ALONG AND JUST WEST OF A WEAK CONVERGENCE ZONE SET UP JUST EAST OF
HIGHWAY 77 WHERE SOMEWHAT STRONGER EASTERLY ONSHORE WINDS MET
LIGHTER WINDS OVER LAND. EXPECTING THE CELLS THAT HAVE INITIATED
TO CONTINUE MOVING JUST SOUTH OF WEST AT AROUND 15 MPH WITH NEW
DEVELOPMENT ALONG THE BOUNDARY FOR ANOTHER FEW HOURS. AN OUTFLOW
BOUNDARY ALSO IS EVIDENT BETWEEN HARLINGEN AND BROWNSVILLE...AND
THE REMNANT OF PREVIOUS CONVECTION OVER THE GULF SHOWS WEAK
CONVERGENCE ON DOPPLER VELOCITIES IN A WEAK MCV TYPE FORM AS IT
MOVES SLOWLY WEST ONSHORE NEAR SOUTH PADRE ISLAND. THIS FEATURE COULD
INITIATE NEW CONVECTION AS IT MOVES INTO MORE UNSTABLE AIR INLAND.
COLUMN CONTINUES TO SATURATE FURTHER AMID DEEP EASTERLY ONSHORE
WINDS...INCREASING CLOUD COVER FROM CU AND ANVIL DEBRIS IS SLOWING
THE INCREASE OF HEATING AND INSTABILITY BUT EXPECT THE BEST
CONVERGENCE TO SLOWLY MOVE WEST THROUGH THE DAY MOVING TO NEAR
HIGHWAY 281 BY 2 TO 3 PM AND A CHANCE CONTINUES FOR CONVECTION TO
MOVE WEST INTO STARR/ZAPATA/JIM HOGG COUNTY LATER THIS AFTERNOON.
TWEAKED NEAR TERM TEMP GRIDS/AFTERNOON MAX TS WHERE CONVECTION WAS
PLAYING A ROLE AND MADE MINOR TIMING/POP ADJUSTMENTS TO THE
FORECAST. /68-JGG/
PREV DISCUSSION... /ISSUED 933 AM CDT SAT AUG 10 2013/
DISCUSSION...MORNING SOUNDING AND SATELLITE DERIVED PRECIPITABLE
WATER ESTIMATES CONTINUE TO INDICATE A VERY SATURATED
AIRMASS...ASSOCIATED WITH A TROPICAL WAVE MOVING WESTWARD ACROSS
THE WEST CENTRAL GULF HAS MOVED INTO THE AREA. RAP AND MODIFIED
MORNING FORECAST SOUNDINGS INDICATE WE ARE APPROACHING CONVECTIVE
TEMPERATURE WITH LITTLE LOWER TROPOSPHERIC WARMING EXPECTED DUE TO
THE SATURATED AIRMASS AND CU STREAKS AND CONVERGENCE ZONES ARE
BECOMING READILY APPARENT ON VISIBLE SATELLITE IMAGERY. THE TWO
STRONGEST ZONES ARE ASSOCIATED WITH THE SEABREEZE IN EASTERN
CAMERON AND WILLACY COUNTY...AND DEVELOPING SHOWER ACTIVITY NEAR
WESLACO. A GENERALLY DIFFLUENT UPPER LEVEL PATTERN JUST OFFSHORE
IS PRODUCING WIDESPREAD SHOWERS AND A FEW THUNDERSTORMS OVER OUR
COASTAL WATERS FOCUSED ALONG WEAK SURFACE TROUGHING MOVING SLOWLY
WESTWARD UNDER THIS FEATURE.
ALL THAT BEING SAID EXPECTING CONVECTIVE DEVELOPMENT TO INCREASE
MARKEDLY OVER THE NEXT TWO TO THREE HOURS WITH SCATTERED TO
NUMEROUS SHOWERS AND STORMS DEVELOPING...POSSIBLY BECOMING
WIDESPREAD IF THE MORE FAVORABLE UPPER LEVEL ENVIRONMENT OVER THE
GULF MOVES ONSHORE. HOWEVER NEAR AND SHORT TERM GUIDANCE HAS BEEN
CONSISTENTLY SHOWING WEAKENING OF THIS FEATURE AS IT MOVES INLAND.
NEVERTHELESS THE CURRENT THERMODYNAMIC AND MOISTURE PROFILE WILL
PROVIDE SHRA/TSRA. THE SHOWERS SHOULD GREATLY OUTNUMBER THE STORMS
BUT THERE WILL PROBABLY BE A FEW RUMBLES OF THUNDER.
THE STRONGEST CELLS WILL PRODUCE EXCEPTIONALLY EFFICIENT RAINFALL
RATES...ON THE ORDER OF TWO TO THREE INCHES PER HOUR AS THEY MOVE
WEST AT AROUND 15 MPH. MOST CONVECTION WILL PROBABLY BE LESS
INTENSE HOWEVER...AND PRODUCE RAINFALL RATES CLOSER TO ONE HALF TO
TWO INCHES PER HOUR. TOTAL ACCUMULATIONS AT ANY ONE LOCATION WILL
LIKELY BE LESS AS THE ACTIVITY MOVES SLOWLY WESTWARD. THE GRIDDED
FORECASTS SHOW THE ANTICIPATED EVOLUTION WELL AND NO SIGNIFICANT
CHANGES ARE PLANNED FOR NOW. /68-JGG/
PREV DISCUSSION... /ISSUED 634 AM CDT SAT AUG 10 2013/
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
AVIATION...EXPECTING CONVECTION TO DEVELOP LATER THIS MORNING
FIRST ALONG THE COAST AND THEN MOVE INLAND THIS AFTERNOON.
EXPECTING BEST CHANCES AND COVERAGE BETWEEN 16-21Z IN THE EAST
AND 18-23Z IN THE CENTRAL AND WEST. VFR CONDITIONS TO PREVAIL
OUTSIDE OF THE CONVECTION WITH TEMPORARY MVFR CIGS VSBY IN AND
NEAR THE SCATTERED THUNDERSTORMS AND SHOWERS. MOISTURE VALUES TO
REMAIN RATHER HIGH SO EXPECT A LAYER OF STRATUS TO DEVELOP
OVERNIGHT AOA MVFR. SURFACE WIND TO REMAIN LIGHT FROM A GENERAL
EAST DIRECTION.
PREV DISCUSSION... /ISSUED 403 AM CDT SAT AUG 10 2013/
SHORT TERM /NOW THROUGH SUNDAY/...SATELLITE AND RADAR LOOPS
INDICATE MOISTURE IS BEGINNING TO MOVE INTO COASTAL WATERS.
SHOWERS AND AN ISOLATED THUNDERSTORM OR TWO HAVE BEEN MOVING INTO
NORTHEAST MEXICO SINCE 1AM IN ADVANCE OF THE LARGE SCALE MID TO
UPPER LEVEL TROUGH CENTERED JUST NORTH OF THE YUCATAN.
FOR TODAY...LOOKING AT SHOWERS THIS MORNING TO FAVOR THE IMMEDIATE
COASTAL AREAS AND THE GULF WATERS. NOT UNTIL THE MOISTURE COLUMN
BECOMES NEARLY SATURATED AROUND OR AFTER 18Z AND PWATS EXCEED 2.25
INCHES WILL WE SEE CONVECTION DEVELOP FARTHER INLAND. A DEEPENING
EASTERLY FLOW TO ENHANCE SURFACE CONVERGENCE ALONG THE SEABREEZE AND
DESTABILIZATION OF THE ATMOSPHERE AS SURFACE HEATING GETS GOING THIS
MORNING BEFORE THE CLOUDS INCREASE TO GIVE THE LOWER AND MID VALLEY
THE BEST AND HIGHEST CHANCE OF RAIN IN LONG WHILE. INHERITED
FORECAST LOOKS GOOD AND REMAINS IN LINE WITH LATEST GUIDANCE. DID
NOT MENTION HEAVY RAIN IN THE FORECAST WITH THE ANTICIPATION OF
CELLS TO MOVE STEADILY EAST TO WEST UNDER A 15 TO 20 KNOT MID LAYER
FLOW. SURFACE TROUGHING LOOKS TO REMAIN JUST OFFSHORE ALONG WITH
UPPER DIVERGENCE KEEPING CONVECTION INITIATION EAST OF THE COAST
WITH THE HEAVIEST AND MOST CONCENTRATED AREA OF RAIN OFFSHORE.
WITH THIS SAID POCKETS OF HEAVY RAIN ARE STILL POSSIBLE INLAND...AS
MOISTURE INCREASES...AND ANY WESTWARD SHIFT OF THE TROUGH COULD PUSH
THE HEAVIER RAIN INLAND. TEMPERATURES TO CLIMB QUICKLY WITH SUNNY
CONDITIONS EARLY ON ESPECIALLY OUT WEST. THEN THEY ARE LIKELY TO
FALL AS RAIN DEVELOPS.
TONIGHT...UPPER TROUGH CONTINUES TO TRACK WESTWARD. CONVECTION TO
WANE INLAND AS STABILIZATION OCCURS WITH WESTERN AREAS SEEING SOME
RAIN LINGER PASS SUNSET. CONVECTION TO REFIRE OVERNIGHT OFFSHORE AS
THE UPPER TROUGH AXIS NEARS THE COAST AND NOCTURNAL DESTABILIZATION
OCCURS. SOME SHOWERS TO WORK THEIR WAY INLAND ACROSS THE LOWER
VALLEY AS THE SURFACE TROUGH NEARS THE COAST.
SUNDAY...ANOTHER GOOD CHANCE OF SHOWERS AND THUNDERSTORMS AS THE
UPPER TROUGH AXIS MOVES OVERHEAD. SOUTH TEXAS WILL BE ON THE
NORTHERN PERIPHERY OF THE TROUGH WITH BETTER CONVERGENCE AND
INSTABILITY SHIFTING FARTHER TO THE SOUTH WITH THE CENTER OF THE
TROUGH. IN ANY CASE...MOISTURE VALUES AND DEEP EASTERLY TO KEEP RAIN
CHANCES RATHER HIGH CONSIDERING THE LAST TWO WEEKS. FORECAST REMAINS
IN RANGE OF MAV/GFS GUIDANCE WITH MET/NAM LOOKING TO HIGH WITH A
MORE ROBUST SURFACE DEVELOPMENT WHICH DOES ON LOOK REASONABLE.
DAYTIME DESTABILIZATION TO TAKE PLACE BUT COULD BE LIMITED WITH
MULTI LAYERED CLOUD COVER LIMITED SURFACE HEATING. WITH THIS SAID
TEMPERATURES TO BE 7 TO 10 DEGREES COOLER THEN THE EXTREME HEAT THAT
WE HAVE EXPERIENCED.
LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...BY SUNDAY NIGHT THE
INVERTED TROUGH AXIS WILL BE TO THE WEST OF THE VALLEY. MOISTURE
WILL STILL BE SUBSTANTIAL...WITH PW VALUES BEGINNING THE PERIOD AT
2 INCHES...SLOWLY FALLING TO 1.6 BY TUESDAY MORNING. WITH THE
ABUNDANCE OF MOISTURE STILL PRESENT...STILL FEEL THAT SEABREEZE
SHOWERS WILL SPARK DURING THE AFTERNOON MONDAY...ALBEIT NOT AS
WIDESPREAD AS OVER THE WEEKEND. H5 RIDGE REBUILDS ACROSS TEXAS IN
THE WAKE OF THE TROUGH ON TUESDAY...WITH PW VALUES AOB 1.5 INCHES
THROUGH THE REST OF THE WEEK. THIS PRECLUDES THE CHANCE OF ANY
SEABREEZE ACTIVITY. TEMPERATURES WILL START TO RECOVER ON
MONDAY...JUMPING BACK INTO THE UPPER 90S AND LOW 100S. A GRADUAL
RETURN TO WIDESPREAD 100 DEGREE TEMPERATURES WILL CONTINUE THROUGH
THE REST OF THE WEEK.
MARINE...
NOW THROUGH SUNDAY...THE APPROACH OF THE UPPER TROUGH AND A
SURFACE TROUGH TO KEEP AN EAST WIND AT LIGHT TO MODERATE LEVELS
TODAY THROUGH SUNDAY. SHOWERS AND THUNDERSTORMS TO INCREASE IN
COVERAGE AND INTENSITY THROUGH THE PERIOD PRODUCING A SLIGHTLY
HIGHER SEA TONIGHT AND SUNDAY. NO SMALL CRAFT ADVISORIES ARE
ANTICIPATED.
MONDAY NIGHT THROUGH THURSDAY...WEAK GRADIENT WILL BE THE RULE
ACROSS THE MARINE ZONES THROUGH THE WEEK...WITH ONSHORE FLOW OF 10
TO 15 KNOTS EXPECTED EACH DAY. SEAS WILL GENERALLY RUN 2 TO 4
FEET...APPROACHING 5 FEET INITIALLY MONDAY NIGHT INTO TUESDAY. NO
ADVISORIES ARE EXPECTED.
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
68/67
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
1206 PM CDT SAT AUG 10 2013
.DISCUSSION...RADAR SHOWS SCATTERED TO NUMEROUS CONVECTIVE CELLS
ALONG AND JUST WEST OF A WEAK CONVERGENCE ZONE SET UP JUST EAST OF
HIGHWAY 77 WHERE SOMEWHAT STRONGER EASTERLY ONSHORE WINDS MET
LIGHTER WINDS OVER LAND. EXPECTING THE CELLS THAT HAVE INITIATED
TO CONTINUE MOVING JUST SOUTH OF WEST AT AROUND 15 MPH WITH NEW
DEVELOPMENT ALONG THE BOUNDARY FOR ANOTHER FEW HOURS. AN OUTFLOW
BOUNDARY ALSO IS EVIDENT BETWEEN HARLINGEN AND BROWNSVILLE...AND
THE REMNANT OF PREVIOUS CONVECTION OVER THE GULF SHOWS WEAK
CONVERGENCE ON DOPPLER VELOCITIES IN A WEAK MCV TYPE FORM AS IT
MOVES SLOWLY WEST ONSHORE NEAR SOUTH PADRE ISLAND. THIS FEATURE COULD
INITIATE NEW CONVECTION AS IT MOVES INTO MORE UNSTABLE AIR INLAND.
COLUMN CONTINUES TO SATURATE FURTHER AMID DEEP EASTERLY ONSHORE
WINDS...INCREASING CLOUD COVER FROM CU AND ANVIL DEBRIS IS SLOWING
THE INCREASE OF HEATING AND INSTABILITY BUT EXPECT THE BEST
CONVERGENCE TO SLOWLY MOVE WEST THROUGH THE DAY MOVING TO NEAR
HIGHWAY 281 BY 2 TO 3 PM AND A CHANCE CONTINUES FOR CONVECTION TO
MOVE WEST INTO STARR/ZAPATA/JIM HOGG COUNTY LATER THIS AFTERNOON.
TWEAKED NEAR TERM TEMP GRIDS/AFTERNOON MAX TS WHERE CONVECTION WAS
PLAYING A ROLE AND MADE MINOR TIMING/POP ADJUSTMENTS TO THE
FORECAST. /68-JGG/
&&
.PREV DISCUSSION... /ISSUED 933 AM CDT SAT AUG 10 2013/
DISCUSSION...MORNING SOUNDING AND SATELLITE DERIVED PRECIPITABLE
WATER ESTIMATES CONTINUE TO INDICATE A VERY SATURATED
AIRMASS...ASSOCIATED WITH A TROPICAL WAVE MOVING WESTWARD ACROSS
THE WEST CENTRAL GULF HAS MOVED INTO THE AREA. RAP AND MODIFIED
MORNING FORECAST SOUNDINGS INDICATE WE ARE APPROACHING CONVECTIVE
TEMPERATURE WITH LITTLE LOWER TROPOSPHERIC WARMING EXPECTED DUE TO
THE SATURATED AIRMASS AND CU STREAKS AND CONVERGENCE ZONES ARE
BECOMING READILY APPARENT ON VISIBLE SATELLITE IMAGERY. THE TWO
STRONGEST ZONES ARE ASSOCIATED WITH THE SEABREEZE IN EASTERN
CAMERON AND WILLACY COUNTY...AND DEVELOPING SHOWER ACTIVITY NEAR
WESLACO. A GENERALLY DIFFLUENT UPPER LEVEL PATTERN JUST OFFSHORE
IS PRODUCING WIDESPREAD SHOWERS AND A FEW THUNDERSTORMS OVER OUR
COASTAL WATERS FOCUSED ALONG WEAK SURFACE TROUGHING MOVING SLOWLY
WESTWARD UNDER THIS FEATURE.
ALL THAT BEING SAID EXPECTING CONVECTIVE DEVELOPMENT TO INCREASE
MARKEDLY OVER THE NEXT TWO TO THREE HOURS WITH SCATTERED TO
NUMEROUS SHOWERS AND STORMS DEVELOPING...POSSIBLY BECOMING
WIDESPREAD IF THE MORE FAVORABLE UPPER LEVEL ENVIRONMENT OVER THE
GULF MOVES ONSHORE. HOWEVER NEAR AND SHORT TERM GUIDANCE HAS BEEN
CONSISTENTLY SHOWING WEAKENING OF THIS FEATURE AS IT MOVES INLAND.
NEVERTHELESS THE CURRENT THERMODYNAMIC AND MOISTURE PROFILE WILL
PROVIDE SHRA/TSRA. THE SHOWERS SHOULD GREATLY OUTNUMBER THE STORMS
BUT THERE WILL PROBABLY BE A FEW RUMBLES OF THUNDER.
THE STRONGEST CELLS WILL PRODUCE EXCEPTIONALLY EFFICIENT RAINFALL
RATES...ON THE ORDER OF TWO TO THREE INCHES PER HOUR AS THEY MOVE
WEST AT AROUND 15 MPH. MOST CONVECTION WILL PROBABLY BE LESS
INTENSE HOWEVER...AND PRODUCE RAINFALL RATES CLOSER TO ONE HALF TO
TWO INCHES PER HOUR. TOTAL ACCUMULATIONS AT ANY ONE LOCATION WILL
LIKELY BE LESS AS THE ACTIVITY MOVES SLOWLY WESTWARD. THE GRIDDED
FORECASTS SHOW THE ANTICIPATED EVOLUTION WELL AND NO SIGNIFICANT
CHANGES ARE PLANNED FOR NOW. /68-JGG/
PREV DISCUSSION... /ISSUED 634 AM CDT SAT AUG 10 2013/
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
AVIATION...EXPECTING CONVECTION TO DEVELOP LATER THIS MORNING
FIRST ALONG THE COAST AND THEN MOVE INLAND THIS AFTERNOON.
EXPECTING BEST CHANCES AND COVERAGE BETWEEN 16-21Z IN THE EAST
AND 18-23Z IN THE CENTRAL AND WEST. VFR CONDITIONS TO PREVAIL
OUTSIDE OF THE CONVECTION WITH TEMPORARY MVFR CIGS VSBY IN AND
NEAR THE SCATTERED THUNDERSTORMS AND SHOWERS. MOISTURE VALUES TO
REMAIN RATHER HIGH SO EXPECT A LAYER OF STRATUS TO DEVELOP
OVERNIGHT AOA MVFR. SURFACE WIND TO REMAIN LIGHT FROM A GENERAL
EAST DIRECTION.
PREV DISCUSSION... /ISSUED 403 AM CDT SAT AUG 10 2013/
SHORT TERM /NOW THROUGH SUNDAY/...SATELLITE AND RADAR LOOPS
INDICATE MOISTURE IS BEGINNING TO MOVE INTO COASTAL WATERS.
SHOWERS AND AN ISOLATED THUNDERSTORM OR TWO HAVE BEEN MOVING INTO
NORTHEAST MEXICO SINCE 1AM IN ADVANCE OF THE LARGE SCALE MID TO
UPPER LEVEL TROUGH CENTERED JUST NORTH OF THE YUCATAN.
FOR TODAY...LOOKING AT SHOWERS THIS MORNING TO FAVOR THE IMMEDIATE
COASTAL AREAS AND THE GULF WATERS. NOT UNTIL THE MOISTURE COLUMN
BECOMES NEARLY SATURATED AROUND OR AFTER 18Z AND PWATS EXCEED 2.25
INCHES WILL WE SEE CONVECTION DEVELOP FARTHER INLAND. A DEEPENING
EASTERLY FLOW TO ENHANCE SURFACE CONVERGENCE ALONG THE SEABREEZE AND
DESTABILIZATION OF THE ATMOSPHERE AS SURFACE HEATING GETS GOING THIS
MORNING BEFORE THE CLOUDS INCREASE TO GIVE THE LOWER AND MID VALLEY
THE BEST AND HIGHEST CHANCE OF RAIN IN LONG WHILE. INHERITED
FORECAST LOOKS GOOD AND REMAINS IN LINE WITH LATEST GUIDANCE. DID
NOT MENTION HEAVY RAIN IN THE FORECAST WITH THE ANTICIPATION OF
CELLS TO MOVE STEADILY EAST TO WEST UNDER A 15 TO 20 KNOT MID LAYER
FLOW. SURFACE TROUGHING LOOKS TO REMAIN JUST OFFSHORE ALONG WITH
UPPER DIVERGENCE KEEPING CONVECTION INITIATION EAST OF THE COAST
WITH THE HEAVIEST AND MOST CONCENTRATED AREA OF RAIN OFFSHORE.
WITH THIS SAID POCKETS OF HEAVY RAIN ARE STILL POSSIBLE INLAND...AS
MOISTURE INCREASES...AND ANY WESTWARD SHIFT OF THE TROUGH COULD PUSH
THE HEAVIER RAIN INLAND. TEMPERATURES TO CLIMB QUICKLY WITH SUNNY
CONDITIONS EARLY ON ESPECIALLY OUT WEST. THEN THEY ARE LIKELY TO
FALL AS RAIN DEVELOPS.
TONIGHT...UPPER TROUGH CONTINUES TO TRACK WESTWARD. CONVECTION TO
WANE INLAND AS STABILIZATION OCCURS WITH WESTERN AREAS SEEING SOME
RAIN LINGER PASS SUNSET. CONVECTION TO REFIRE OVERNIGHT OFFSHORE AS
THE UPPER TROUGH AXIS NEARS THE COAST AND NOCTURNAL DESTABILIZATION
OCCURS. SOME SHOWERS TO WORK THEIR WAY INLAND ACROSS THE LOWER
VALLEY AS THE SURFACE TROUGH NEARS THE COAST.
SUNDAY...ANOTHER GOOD CHANCE OF SHOWERS AND THUNDERSTORMS AS THE
UPPER TROUGH AXIS MOVES OVERHEAD. SOUTH TEXAS WILL BE ON THE
NORTHERN PERIPHERY OF THE TROUGH WITH BETTER CONVERGENCE AND
INSTABILITY SHIFTING FARTHER TO THE SOUTH WITH THE CENTER OF THE
TROUGH. IN ANY CASE...MOISTURE VALUES AND DEEP EASTERLY TO KEEP RAIN
CHANCES RATHER HIGH CONSIDERING THE LAST TWO WEEKS. FORECAST REMAINS
IN RANGE OF MAV/GFS GUIDANCE WITH MET/NAM LOOKING TO HIGH WITH A
MORE ROBUST SURFACE DEVELOPMENT WHICH DOES ON LOOK REASONABLE.
DAYTIME DESTABILIZATION TO TAKE PLACE BUT COULD BE LIMITED WITH
MULTI LAYERED CLOUD COVER LIMITED SURFACE HEATING. WITH THIS SAID
TEMPERATURES TO BE 7 TO 10 DEGREES COOLER THEN THE EXTREME HEAT THAT
WE HAVE EXPERIENCED.
LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...BY SUNDAY NIGHT THE
INVERTED TROUGH AXIS WILL BE TO THE WEST OF THE VALLEY. MOISTURE
WILL STILL BE SUBSTANTIAL...WITH PW VALUES BEGINNING THE PERIOD AT
2 INCHES...SLOWLY FALLING TO 1.6 BY TUESDAY MORNING. WITH THE
ABUNDANCE OF MOISTURE STILL PRESENT...STILL FEEL THAT SEABREEZE
SHOWERS WILL SPARK DURING THE AFTERNOON MONDAY...ALBEIT NOT AS
WIDESPREAD AS OVER THE WEEKEND. H5 RIDGE REBUILDS ACROSS TEXAS IN
THE WAKE OF THE TROUGH ON TUESDAY...WITH PW VALUES AOB 1.5 INCHES
THROUGH THE REST OF THE WEEK. THIS PRECLUDES THE CHANCE OF ANY
SEABREEZE ACTIVITY. TEMPERATURES WILL START TO RECOVER ON
MONDAY...JUMPING BACK INTO THE UPPER 90S AND LOW 100S. A GRADUAL
RETURN TO WIDESPREAD 100 DEGREE TEMPERATURES WILL CONTINUE THROUGH
THE REST OF THE WEEK.
MARINE...
NOW THROUGH SUNDAY...THE APPROACH OF THE UPPER TROUGH AND A
SURFACE TROUGH TO KEEP AN EAST WIND AT LIGHT TO MODERATE LEVELS
TODAY THROUGH SUNDAY. SHOWERS AND THUNDERSTORMS TO INCREASE IN
COVERAGE AND INTENSITY THROUGH THE PERIOD PRODUCING A SLIGHTLY
HIGHER SEA TONIGHT AND SUNDAY. NO SMALL CRAFT ADVISORIES ARE
ANTICIPATED.
MONDAY NIGHT THROUGH THURSDAY...WEAK GRADIENT WILL BE THE RULE
ACROSS THE MARINE ZONES THROUGH THE WEEK...WITH ONSHORE FLOW OF 10
TO 15 KNOTS EXPECTED EACH DAY. SEAS WILL GENERALLY RUN 2 TO 4
FEET...APPROACHING 5 FEET INITIALLY MONDAY NIGHT INTO TUESDAY. NO
ADVISORIES ARE EXPECTED.
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
68/59